Luminosity and Chromaticity: On Light and Color

Luminosity and Chromaticity: On Light and Color

Key Terms and Ideas

  • Luminosity and Chromaticity
  • Light and Color
  • Diwali (Festival of Light) and Holi (Festival of Colors)
  • Rama and Krishna
  • Non Dual Vedanta and Trika Philosophy
  • 1 and 3
  • Verticalism and Horizontalism
  • Vedic and Tantric
  • Flute of Krishna and Shiva Jyotir Linga
  • Bow and Arrow of Ram
  • Ram Parivar and Shiv Parivar
  • Shiv Ratri
  • Plato and Aristotle
  • Sun, Moon, Earth and Mars
  • Rods and Cones in Retina
  • Color Temperature
  • Lok and Kosh
  • Seven Chakra
  • Trishool
  • Ram, Lakshman, Sita, Hanuman
  • Achromatic and Chromatic
  • Grey scale and Color Primaries
  • Mind and Moon
  • Moon and Emotions
  • Tone Circle
  • Color Circle
  • Pythagoras
  • 3 and 7
  • 137
  • 007
  • Prism
  • Seven Colors
  • 4 + 3 = 7
  • 4 x 3 = 12
  • Pentatonic
  • Heptatonic
  • Diatonic Scale
  • Chromatic Scale

Newton’s Color Circle

Source: http://winlab.rutgers.edu/~trappe/Courses/ImageVideoS06/MollonColorScience.pdf

Color Circle in Opticks of I.Newton

Source: Reprint of Opticks by Project Gutenberg

Color Sensation

Source: Understanding color & the in-camera image processing pipeline for computer vision

Electromagnetic Spectrum

Source: Notes for the course of Color Digital Image Processing

Color Temperature

Source: Understanding color & the in-camera image processing pipeline for computer vision

Color Temperatures of the Stars

Luminosity Function

Source: Understanding color & the in-camera image processing pipeline for computer vision

CIE 1931 XYZ

Source: Understanding color & the in-camera image processing pipeline for computer vision

Luminance

Source: Human Vision and Color

Brightness, Lightness,Hue, Saturation, and Luminosity

Source: The Brightness of Colour

Brightness has been defined as the perceived intensity of a visual stimulus, irrespective of its source. Lightness, on the other hand, is defined as the apparent brightness of an object relative to the object’s reflectance. Thus increasing the intensity of light falling on an object will increase its apparent brightness but not necessarily its apparent lightness, other things being equal [1]. Saturation is a measure of the spectral ‘‘purity’’ of a colour, and thus how different it is from a neutral, achromatic stimulus. Hue is the perception of how similar a stimulus is to red, green, blue etc. Luminous efficiency, or luminosity, measures the effect that light of different wavelengths has on the human visual system. It is a function of wavelength, usually written as V(l) [2], and is typically measured by rapidly alternating a pair of stimuli falling on the same area of the retina; the subject alters the physical radiance of one stimulus until the apparent flickering is minimised. Thus luminance is a measure of the intensity of a stimulus given the sensitivity of the human visual system, and so is integrated over wavelength [3]. Luminance is thought to be used by the brain to process motion, form and texture [4].

Clearly, brightness is monotonically related to luminance in the simplest case: the more luminant the stimulus is, the brighter it appears to be. However, the Helmholtz-Kohlrausch (HK) effect shows that the brightness of a stimulus is not a simple representation of luminance, since the brightness of equally luminant stimuli changes with their relative saturation (i.e. strongly coloured stimuli appear brighter than grey stimuli), and with shifts in the spectral distribution of the stimulus (e.g. ‘blues’ and ‘reds’ appear brighter than ‘greens’ and ‘yellows’ at equiluminance) [1; 5–6].

The HK effect has been measured in a variety of psychophysical studies [7–8] and is often expressed in terms of the (variable) ratio between brightness and luminance. 

Chromaticity

Source: Human Vision and Color

Human Eye

Source: Human Vision and Color

Human Retina

Source: Human Vision and Color

Rods and Cones Photoreceptors

Source: Human Vision and Color

Color Receptors

Source: Human Vision and Color

Tristimulus Color

Source: Color/CMU

Visual Sensitivity

Source: Human Vision https://people.cs.umass.edu/~elm/Teaching/ppt/691a/CV%20UNIT%20Light/691A_UNIT_Light_1.ppt.pdf

Light and Color (Photometry and Colorimetry) I

Source: Interactive Computer Graphics/UOMichigan

Light and Color (Photometry and Colorimetry) II

Source: Interactive Computer Graphics/UOMichigan

Two Types of Light Sensitive Cells

Source: Interactive Computer Graphics/UOMichigan

Cones and Rod Sensitivity

Source: Interactive Computer Graphics/UOMichigan

Distribution of Cones in Retina

Source: DIVERSE CELL TYPES, CIRCUITS, AND MECHANISMS FOR COLOR VISION IN THE VERTEBRATE RETINA

Types of Color Stimuli

Source: Perceiving Color. https://www.ics.uci.edu/~majumder/vispercep/chap5notes.pdf

Color Perception

Source: Perceiving Color. https://www.ics.uci.edu/~majumder/vispercep/chap5notes.pdf

CIE XYZ Model

Source: Human Vision and Color

Luminance and Chromaticity Space

Source: Understanding color & the in-camera image processing pipeline for computer vision

1931 CIE Chromaticity Chart

CIE 1931 Chromaticity Diagram

Source: Human Vision and Color

Source: Notes for the course of Color Digital Image Processing

Additive Colors

Source: Human Vision and Color

Subtractive Colors

Source: Human Vision and Color

Color Mixing

Source: Human Vision and Color

Color Appearance Models
  • RGB
  • CMY
  • CIE XYZ
  • CIE xyY
  • CIE LAB
  • Hunter LAB
  • CIE LUV
  • CIE LCH
  • HSB
  • HSV
  • HSL
  • HSI
  • YIQ for NTSC TVs in USA
  • YUV for PAL TVs in EU
  • YCbCr for digital TVs
  • Munsell Color System

Color Models are device independent. For discussion of device dependent color spaces, please see my post Digital Color and Imaging.

LMS, RGB, and CIE XYZ Color Spaces

Source: Color/CMU

HSV Color Space

My Related Posts

Reflective Display Technology: Using Pigments and Structural Colors

Color Science and Technology in LCD and LED Displays

Color Science of Gem Stones

Nature’s Fantastical Palette: Color From Structure

Optics of Metallic and Pearlescent Colors

Color Change: In Biology and Smart Pigments Technology

Color and Imaging in Digital Video and Cinema

Digital Color and Imaging

On Luminescence: Fluorescence, Phosphorescence, and Bioluminescence

On Light, Vision, Appearance, Color and Imaging

Understanding Rasa: Yoga of Nine Emotions

Shapes and Patterns in Nature

Key Sources of Research

What Are The Characteristics Of Color?

https://www.pantone.com/articles/color-fundamentals/what-are-the-characteristics-of-color

Birren Color Theory

by ADMIN on MARCH 11, 2012

http://www.wonderfulcolors.org/blog/birren-color-theory/

Light, Color, Perception, and Color Space Theory

Professor Brian A. Barsky

barsky@cs.berkeley.edu

Computer Science Division
Department of Electrical Engineering and Computer Sciences University of California, Berkeley

Understanding Color Spaces and Color Space Conversion

https://www.mathworks.com/help/images/understanding-color-spaces-and-color-space-conversion.html

The Human Visual System and Color Models

Click to access Carmody_Visual&ColorModels.pdf

Defining and Communicating Color: The CIELAB System

Color Vision and Arts

http://www.webexhibits.org/colorart/index.html

PRECISE COLOR COMMUNICATION: COLOR CONTROL FROM PERCEPTION TO INSTRUMENTATION

KonicaMinolta

A short history of color theory

https://programmingdesignsystems.com/color/a-short-history-of-color-theory/index.html

Let’s Colormath

Understanding the formulas of color conversion

https://donatbalipapp.medium.com/colours-maths-90346fb5abda

A History of Human Color Vision—from Newton to Maxwell

Barry R. Masters

Optics and Photonics January 2011

https://www.osa-opn.org/home/articles/volume_22/issue_1/features/a_history_of_human_color_vision—from_newton_to_max/

The Difference Between Chroma and Saturation

Munsell Color

Charles S. Peirce’s Phenomenology: Analysis and Consciousness

By Richard Kenneth Atkins

The Evolution of Human Color Vision/ Jeremy Nathans

Jeremy Nathans Lecture on Color Vision

JEREMY NATHANS LECTURE ON COLOR VISION

JEREMY NATHANS LECTURE ON COLOR VISION

JEREMY NATHANS LECTURE ON COLOR VISION

The Genes for Color Vision

Jeremy Nathans

SCIENTIFIC AMERICAN FEBRUARY 1989

A Short History of Color Photography

Photography  |  Angie Kordic

https://www.widewalls.ch/magazine/color-photography

Blue: The History of a Color (2001)

followed by Black: The History of a Color (2009) and then Green: The History of a Color (2014), all produced by the same publisher. A fifth, devoted to yellow, should come next. 

Historic Look on Color Theory 

Steele R. Stokley

The evolution of colour in design from the 1950s to today

Francesca Valan

Journal of the International Colour Association (2012): 8, 55-60

Greek Color Theory and the Four Elements

J.L. Benson

University of Massachusetts Amherst

A SHORT HISTORY OF COLOUR PHOTOGRAPHY

https://blog.scienceandmediamuseum.org.uk/a-short-history-of-colour-photography/

History of Color System

The Origins of Modern Color Science

J D Mollon

Click to access MollonColorScience.pdf

The History of Colors

Tobias Kiefer

Click to access Assignment_History_of_Colors.PDF

Notes for the course of Color Digital Image Processing

Edoardo Provenzi

Understanding color & the in-camera image processing pipeline for computer vision

Dr. Michael S. Brown

Canada Research Chair Professor York University – Toronto

ICCV 2019 Tutorial – Seoul, Korea

Chapter 2
Basic Color Theory

Click to access t3.pdf

Color Science

CS 4620 Lecture 26

Click to access 26color.pdf

Color Image Perception, Representation and Contrast Enhancement

Yao Wang
Tandon School of Engineering, New York University

A GUIDE TO LIGHT AND COLOUR DEMONSTRATIONS

Arne Valberg, Bjørg Helene Andorsen, Kine Angelo, Barbara Szybinska Matusiak and Claudia Moscoso

Norwegian University of Science and Technology Trondheim, Norway

https://www.ntnu.edu/documents/1272527942/1272817015/2015-09-08+DEMO+web.pdf/f1695ca5-b834-4d05-a011-a185f6562e32

A Primer to Colors in Digital Design

Archit Jha

Jul 16, 2017

https://uxdesign.cc/a-primer-to-colors-in-digital-design-7d16bb33399e

Chapter 7 ADDITIVE COLOR MIXING

Click to access 07_additive-color.pdf

Computergrafik

Matthias Zwicker Universität Bern Herbst 2016

Color

Click to access ColorPerception.pdf

Introduction to Computer Vision

The Perception of Color

In: Webvision: The Organization of the Retina and Visual System [Internet]. Salt Lake City (UT): University of Utah Health Sciences Center; 1995–.2005 May 1 [updated 2007 Jul 9]

https://pubmed.ncbi.nlm.nih.gov/21413396/

Visual Pigment Gene Structure and Expression in Human Retinae 

Tomohiko Yamaguchi,  Arno G. Motulsky,  Samir S. Deeb

Human Molecular Genetics, Volume 6, Issue 7, July 1997, Pages 981–990, https://doi.org/10.1093/hmg/6.7.981

https://academic.oup.com/hmg/article/6/7/981/572151

The Difference Between Chroma and Saturation

LUMINANCE AND CHROMATICITY

https://colorusage.arc.nasa.gov/lum_and_chrom.php

Number by Colors

A Guide to Using Color to Understand Technical Data
  • Brand Fortner
  • Theodore E. Meyer

Chapter 5 Perceiving Color

The Practical Guide To Color Theory For Photographers

History of the Bauhaus

https://bauhaus.netlify.app/form_color/color/

The Digital Artist’s Complete Guide To Mastering Color Theory

byLeigh G

BASIC COLOR THEORY

Anthony Holdsworth

Molecular Genetics of Color Vision and Color Vision Defects

Maureen Neitz, PhDJay Neitz, PhD

Arch Ophthalmol. 2000;118(5):691-700. doi:10.1001/archopht.118.5.691

https://jamanetwork.com/journals/jamaophthalmology/fullarticle/413200

Color Theory: Introduction to Color Theory and the Color Wheel

https://blog.thepapermillstore.com/color-theory-introduction-color-wheel/

Color Spaces and Color Temperature

https://tigoe.github.io/LightProjects/color-spaces-color-temp.html

The Brightness of Colour

David Corney1, John-Dylan Haynes2, Geraint Rees3,4, R. Beau Lotto1*

EECS 487: Interactive Computer Graphics

Colorimetry

KonicaMinolta

Basics of Color Theory

THE BASICS OF COLOR PERCEPTION AND MEASUREMENT

Hunterlab

https://www.hunterlab.com/color-measurement-learning/glossary/

Color Matching and Color Discrimination

The Science of Color

2003

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.457.9467&rep=rep1&type=pdf

1.3 Color Temperature

https://www.mat.univie.ac.at/~kriegl/Skripten/CG/CG.html

https://www.mat.univie.ac.at/~kriegl/Skripten/CG/node10.html

Color Spaces and Color Temperature

https://tigoe.github.io/LightProjects/color-spaces-color-temp.html

Digital Camera Sensor Colorimetry

Douglas A. Kerr

Click to access Sensor_Colorimetry.pdf

Chromatic luminance, colorimetric purity, and optimal aperture‐color stimuli

DOI: 10.1002/col.20356

https://www.researchgate.net/publication/230164581_Chromatic_luminance_colorimetric_purity_and_optimal_aperture-color_stimuli

Title: A Review of RGB Color Spaces …from xyY to R’G’B’

The CIE XYZ and xyY Color Spaces

Douglas A. Kerr

Click to access CIE_XYZ.pdf

DIVERSE CELL TYPES, CIRCUITS, AND MECHANISMS FOR COLOR VISION IN THE VERTEBRATE RETINA

Wallace B. Thoreson and Dennis M. Dacey

Department of Ophthalmology and Visual Sciences, Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, Nebraska; and Department of Biological Structure, Washington National Primate Research Center, University of Washington, Seattle, Washington

Physiol Rev 99: 1527–1573, 2019 Published May 29, 2019; doi:10.1152/physrev.00027.2018

https://journals.physiology.org/doi/pdf/10.1152/physrev.00027.2018

Human Vision

Introduction to color theory

https://graphics.stanford.edu/courses/cs178-10/applets/locus.html

COLOR WHEELS

https://www2.bellevuecollege.edu/artshum/materials/art/tanzi/Winter04/111/111CLRWHLSW04.htm

Human Vision and Color

UT

Click to access 121.pdf

COLOR VISION MECHANISMS

Andrew Stockman

Department of Visual Neuroscience UCL Institute of Opthalmology London, United KIngdom

David H. Brainard

Department of Psychology University of Pennsylvania Philadelphia, Pennsylvania

Color

CMU

Click to access lecture15.pdf

What Are The Characteristics Of Color?

Pantone

https://www.pantone.com/articles/color-fundamentals/what-are-the-characteristics-of-color

A Guide to Color


Guide C-316
Revised by Jennah McKinley

https://aces.nmsu.edu/pubs/_c/C316/welcome.html

A History of Color

The Evolution of Theories of Lights and Color
  • Robert A. Crone

https://link.springer.com/book/10.1007/978-94-007-0870-9

The Brilliant History of Color in Art

Victoria Finlay

A History of Light and Colour Measurement
Science in the Shadows

Sean F Johnston

University of Glasgow, Crichton Campus, UK

Color codes: modern theories of color in philosophy, painting and architecture, literature, music and psychology

Charles Riley

Chapter 6 Colour

History of Color Systems

Reflective Display Technology: Using Pigments and Structural Colors

Reflective Display Technology: Using Pigments and Structural Colors

Source: E-Ink Inc.

Key Terms

  • E Ink
  • E Paper
  • ACeP (Advanced Colors e Paper)
  • E Readers
  • Note/Writing Pads
  • E Labels
  • E TAG
  • E Newspaper
  • E Whiteboard
  • ESL (Electronic Shelf Label)
  • Signage
  • Displays
  • Reflective Displays
  • Flexible Displays
  • LCD/LED Displays
  • QLED
  • OLED (Organic Light Emitting Diodes)
  • AM-OLED
  • Electrowetting Display (EWD)
  • Glass Based e Paper
  • Flexible e Paper
  • CLEARInk (E Ink + LCD)
  • CFA (Color Filter Array)
  • Electrophoretic display (EPD)
  • OTFT (Organic Thin Film Transistors)
  • Flexible AM OLED
  • Flexible AM EPD
  • Active Matrix OLED (AM-OLED)
  • Organic Electronics
  • Flexible Electronics
  • Printed Electronics
  • Conjugated Conducting Polymers
  • Transparent Displays
  • Luminescent Displays
  • Passive Matrix (PM)
  • Reflective LCD
  • Transmissive LCD
  • Transflective LCD
  • Cholesteric Liquid Crystals
  • ElectroChromic Displays (ECD)
  • ElectroFluidic Displays (EFD)
  • Photonic Crystals Displays
  • Plasmonic Colors Displays

Source: Active control of plasmonic colors: emerging display technologies

Source: Review of Paper-Like Display Technologies

Technology of Dyes, Pigments, and Structural Colors

Source: Chromic Phenomena: Technological Applications of Colour Chemistry

Reflective Color Generation Technology in Displays

  • Pigmentation
  • Structural

Source: DYNAMICALLY TUNABLE PLASMONIC STRUCTURAL COLOR

Review Paper: A critical review of the present and future prospects for electronic paper

Review Paper: A critical review of the present and future prospects for electronic paper

Types of Reflective e-Paper Technologies
(Color and Monochrome)

  • Electrophoretic
  • In-plane Electrophoretic
  • Electrokinetic
  • Liquid Powder
  • Electrochromic
  • Electrowetting
  • Electrofluidic
  • MEMS (electromechanical interference modulation)
  • Cholesteric liquid-crystal displays (Kent Displays)

Source: Review of Display Technologies Focusing on Power Consumption

Electronic paper, popularly known as e-paper, can be defined as a dynamic display technology that emulates traditional paper. As LCD, e-paper belongs to the non-emissive display category but, in this case, no backlight is needed since the ambient light from the environment is enough.

The display is composed of millions of microcapsules containing positively charged white and negatively charged black particles suspended in a clear liquid, which are capable of producing the resolution only found in print. As they are bi-stable, they only consume power while the display is being updated. The power required for the update process depends on the size of the display.

The first commercial success of monochrome e-paper devices was due to the Electrophoretics technology, wrongly referred to as electronic paper displays (EPD), whose main exponent is microencapsulated electrophoretic displays, also known as e-ink [35]. Another similar approach, microcellular electrophoretic display films (SiPix), was bought by e-ink. There are other proprietary electrophoretic displays, which include Quick-Response Liquid Powder Display (QR-LPD) by Bridgestone [36], bichromal beads [37] by Xerox (Gyricon), or reverse emulsion electrophoretic display (REED) used by Zikon Corp.

Cholesteric liquid crystal (ChLCD), already mentioned as a subgroup of LCD, is generally classified as e-paper because of its zero consumption when it is not receiving screen updates.

Source: Review of Display Technologies Focusing on Power Consumption

A next generation of flexible, color and video e-paper is currently emerging. The most promising seems to be the electro-wetting approach (EWD) [38]. Its main component, liquavista (see Figure 3b), was developed by Philips but currently belongs to Amazon. Another interesting technology based on Interferometric Modulation (IMOD) is microelectromechanical sytems (MEMS) [39], whose potential has been demonstrated through several prototypes (trademarked Mirasol [40]) developed by Qualcomm.

Some other remarkable developments are the in-plane electrophoretics (IPE) patented by Canon [41] and HP’s Electrokinetic (EKD) [42], although they are at least several years away from a general market uptake [43].

Another less matured technology is electrofluidic [44], which presents the main novelty of using a three-dimensional microfluidic device structure and offering brilliantly colored aqueous pigment dispersions. Recently, other lines of investigation have aimed to simulate traditional paper through electronic paper made from microbial cellulose [45].

Source: Biological versus electronic adaptive coloration: how can one inform the other?

Other reflective liquid-crystal displays
  • Conventional reflective polarizer-based liquid crystal
  • Transflective liquid-crystal displays
  • Electromagnetic (EMD ) displays

  • Photonic Crystals Displays (P -Ink)
  • Plasmonic Structural Colors

Other Display Technologies
  • Bistable LCDs – Reflective – Cholesteric
  • Nemoptic – BiNem/OLED dual Mode Display- Sold rights to Seiko Japan
  • ZBD Display – PM-LCD Reflective Display – Acquired by New Vision Display China
  • Fujitsu’s Color E-paper Mobile Display – FLEPia – Discontinued 2010 

Reflective Displays using Pigments

  • Electrophoretic Displays
  • Electrowetting Displays
  • Electrochromic Displays

Electrophoretic Displays – Reflective

(eReaders and Note taking/Writing Pads)

(Monochrome and Color)

(EPD)

  • E ink
  • E Paper
  • Yotaphone
  • E Ink Triton
  • E Ink Triton 2
  • E Ink Kaleido
  • E Ink Kaleido 2
  • Hisense
  • Pocketbook
  • Onyx Boox Poke 2
  • Onyx Max Lumi
  • Quirk logic Papyr
  • Ratta Supernote A5X
  • Onyx Note Air
  • iReader
  • iFLYTEK
  • Amazon Kindle
  • Etch a Sketch
  • Magna Doodle
  • Remarkable 2
  • Ricoh Whiteboard 42 inch
  • Hisense A7 CC 6.7 Inch Smartphone
  • Kobo Libra H20
  • Amazon Paperwhite
  • Amazon Oasis
  • Bigme S3 7.8 Color E-reader
  • Kobo Nia e Readers
  • Boyue Likebook
  • Pocketbook Inkpad Color
  • Onyx Boox Poke 2 Color

Electrophoretic Displays – Reflective

Source: Stretchable and reflective displays: materials, technologies and strategies

Electrophoretic Display

Source: Review Paper: A critical review of the present and future prospects for electronic paper

In-plane Electrophoretic Display

Source: Review Paper: A critical review of the present and future prospects for electronic paper

ElectroKinetic Displays

Source: Review Paper: A critical review of the present and future prospects for electronic paper

Liquid Powder Display

Source: Review Paper: A critical review of the present and future prospects for electronic paper

Companies manufacturing Reflective Displays

The key players in the global e-paper display market are

  • Displaydata Ltd. (UK) 
  • Display Innovations (UK) 
  • Kent Displays, Inc. (USA) 
  • LANCOM Systems GmbH (Germany) 
  • Liquavista B.V. (The Netherlands) 
  • Xerox Corp. (USA) 
  • Zikon, Inc. (USA)
  • Qualcomm
  • Gamma Dynamics
  • ITRI
  • GUANGZHOU OED TECHNOLOGIES CO., LTD
  • InkCase Enterprise Pte Ltd
  • Plastic Logic HK Ltd
  • GDS Holding S.r.l.
  • Epson Europe Electronics GmbH
  • GDS S.p.a
  • Motion Display
  • MPicoSys Low Power Innovators
  • Omni-ID
  • Solomon Systech
  • E Ink Holdings Inc (Taiwan)
  • Sony Corporation (Japan)
  • Pervasive Display Inc (Taiwan)
  • Samsung Display Co, Ltd (South Korea)
  • LG Display Co Ltd. (South Korea)
  • Plastic Logic GmbH (Germany)
  • Cambrios Technologies Corporation (US)
  • Bridgestone Corporation (Japan)
  • Visionect (Slovenia)
  • CLEARink Displays (US)

Global E-Paper Display Market Scope and Market Size

E-paper display market is segmented on the basis of product, type, technology and end user. The growth among segments helps you analyse niche pockets of growth and strategies to approach the market and determine your core application areas and the difference in your target markets.
• E-paper display market on the basis of product has been segmented as e-readers, mobile devices, smart cards, poster & signage, auxiliary displays and electronic shelf label, and wearables.
• Based on technology, e-paper display market has been segmented into electrophoretic display, electrowetting display, cholesteric display, interferometric modular display, and others.
• On the basis of type, e-paper display market has been segmented into flat EPDs, curved EPDs, flexible EPDs, and foldable EPDs
• E-paper display has also been segmented on the basis of end user into automotive, consumer electronics, retail, healthcare and media & entertainment.

E-PAPER DISPLAYS EXPLAINED
We so often eulogise about the limitless possibilities e-paper displays enable and the exciting opportunities the technology creates for market growth, differentiation and competitive advantage — but for the uninitiated reader, we thought it might be helpful in this blog to take a step back and look at how e-paper works.

E-paper goes by many names and spellings — electronic paper, ePaper, electronic ink, e ink, electrophoretic displays, EPD — but all these terms effectively describe the same thing: an electrically-charged surface that replicates the look and experience of ink on paper.

Instead of a traditional display that uses backlighting to illuminate pixels, e-paper is based on the science of “electrophoresis” — i.e. the movement of electrically charged molecules in an electric field.

In every e-paper display there are millions of tiny microcapsules containing (negatively charged) black and (positively charged) white pigments suspended in a clear fluid. This encapsulated ‘ink’ is then printed onto a plastic film and laminated on to a layer of circuitry, or — to be even more specific — a transistor matrix layer. The circuitry forms a pattern of pixels that is then controlled by a display driver (EPD controller).

When a negative electric field is applied to the ‘ink’, the white particles move to the top of the capsule making the surface appear white at that specific spot. Reverse this process and the black particles appear at the top making the surface of the capsule appear dark. The technology can also work in colour in just the same way but using a combination of different colour pigments and electric charges, or just by adding a colour filter on top of the display.

The way e-paper works differs from traditional displays in two key ways:

E-paper screens are reflective — light from the environment is reflected from the surface of the e-paper display towards the user’s eyes, just like with traditional paper. This gives e-paper a wide viewing angle that is readable in direct sunlight.
E-paper screens are bi-stable — unlike conventional backlit flat panel LCD displays, which refresh about 30 times per second and require a constant power supply to maintain content, e-paper displays will hold a static image ‘forever’, even without electricity. E-paper only consumes power when the content on it changes – for example if an e-paper shelf label in a supermarket is updated with a new price. The rest of the time the display will simply show the content you want it to, where it doesn’t draw any power until the next update.

Making e-paper flexible

Here at Plastic Logic Germany, we took e-paper one stage further and successfully industrialised a process to create glass-free backplanes, which represents the transistor matrix layer mentioned above. We are the first company worldwide able to manufacture transistor arrays on plastic. Instead of using traditional silicon transistors, our active-matrix backplane consists of organic thin film transistors (OTFTs) made from the same plastic used to for cola bottles (PET). This means we can couple a flexible backplane with a flexible display medium, such as flexible OLED or flexible electrophoretic layer, to create a fully flexible display with limitless possibilities. In addition to the flexibility, our glass-free electrophoretic displays also more robust, shatterproof and lightweight compared to glass-based displays.

If you want to know more about flexible plastic e-paper display technology’s suitability for a given use case and to get some inspiration via the applications which are already successfully showcasing the opportunities and rewards achievable through flexible e-paper innovation check out our latest flexible e-paper whitepaper.

By Plastic Logic

Flexible Displays
  • Flat
  • Curved
  • Foldable
  • Rollable
  • Printable
  • Without Glass
  • On Plastic

Electrowetting Displays (EWD)
  • LiquaVista
  • Etulipa
  • ADT

CMY Colors vs RGB Colors

Source: Current commercialization status of electrowetting-on-dielectric (EWOD) digital microfluidics

The emergence of electrowetting-on-dielectric (EWOD) in the early 2000s made the once-obscure electrowetting phenomenon practical and led to numerous activities over the last two decades. As an eloquent microscale liquid handling technology that gave birth to digital microfluidics, EWOD has served as the basis for many commercial products over two major application areas: optical, such as liquid lenses and reflective displays, and biomedical, such as DNA library preparation and molecular diagnostics. A number of research or start-up companies (e.g., Phillips Research, Varioptic, Liquavista, and Advanced Liquid Logic) led the early commercialization efforts and eventually attracted major companies from various industry sectors (e.g., Corning, Amazon, and Illumina). Although not all of the pioneering products became an instant success, the persistent growth of liquid lenses and the recent FDA approvals of biomedical analyzers proved that EWOD is a powerful tool that deserves a wider recognition and more aggressive exploration. This review presents the history around major EWOD products that hit the market to show their winding paths to commercialization and summarizes the current state of product development to peek into the future. In providing the readers with a big picture of commercializing EWOD and digital microfluidics technology, our goal is to inspire further research exploration and new entrepreneurial adventures.

Source: Stretchable and reflective displays: materials, technologies and strategies

Liquavista technology was acquired by Samsung and then later was sold to Amazon. Amazon has put it on shelves.

Source: Biological versus electronic adaptive coloration: how can one inform the other?

Electrowetting Display

Source: Review Paper: A critical review of the present and future prospects for electronic paper

ElectroFluidic Display

Source: Review Paper: A critical review of the present and future prospects for electronic paper

Electrochromic Displays

  • mECD by RICOH
  • Transprint method

Source: IllumiPaper: Illuminated Interactive Paper

In general, display technologies can be classified in pixel-addressable high-resolution displays (e.g. OLED, e-paper) and in segment displays, which highlight predefined shapes based on electrochromism (EC) [2], thermochromism (TE) [31] or electroluminescence (EL) [1, 46]. Although advanced display types, such as e-paper, have promising properties (e.g., preserving content without battery), we focus on lightweight, low-current-consuming, segment-based EL and EC displays, which are robust, inexpensive and easy to integrate with pen interaction.

RDOT Tech

Source: Stretchable and reflective displays: materials, technologies and strategies

Electrochromic Displays

Source: Review Paper: A critical review of the present and future prospects for electronic paper

This technology was formerly by Swedish company Rdot, which was co-founded by Karlsson, and bought by Ynvisible Interactive of Vancouver. The company has prototyping capabilities in Linköping, Sweden and in Almada, Portugal, roll-to-roll production in Sweden, and R&D in Freiburg, Germany.

Printed Electrochromics boldly goes where no display has gone before

Ron Mertens

This is a sponsored post by Ynvisible

Example use-case for printed electrochromics, Ynvisible
Fig.1 Example use case for printed electrochromics: a shock detector smart label with an interactive printed interface.

Expanding Need for Simple Electronic Display Functionality

Rapid advances in the miniaturization and reduction of costs in computing, electronic sensing, and communications have allowed the integration of “smart” electronic functionality into almost everything. ”Intelligence” is now embedded into a wide range of everyday objects, and spread throughout our working and living environments. Much of this intelligence, data collection and transfer is hidden from the human senses, requiring little or no human involvement. But as the number of human daily touch points and interactions with smart devices grows, so too does the importance of user experience design and the role of displays.

Conventional electronic displays cannot be economically and sustainably applied into all smart objects and environments and can often times be functionality overkill for the simple display requirements of many everyday objects. Also, user experiences built around the need for extensive use of separate reading devices, e.g. RFID or Bluetooth readers in smart phones, can be increasingly challenging especially with the high number of distractions and strong competition for attention on mobile screens. Further with a doubling of screen time over the past four years among certain user demographics, there is also a growing sense of screen fatigue leading to people “detoxing” from light emitting screens while still valuing user interfaces that are useful yet unobtrusive.

“As technology becomes ubiquitous, it also becomes invisible.“
– Kevin Kelly, Wired magazine Founding Executive Editor

When technology becomes ubiquitous, it needs to seamlessly blend into the product and our surroundings. The user experience should be effortless. As the “computing” or intelligence blends into smart objects and environments, also the displays need to become more practical: i) eliminating the need for recharging or replacing of batteries, ii) eliminating the amount of effort to access information, and iii) be inexpensive for intended purpose.

Printed Electrochromics Brings Everyday Printable Objects and Surfaces to Life

Electrochromic devices (ECD) are electrochemical cells where color changes occur upon electrochemical reactions of two or more redox active electrochromic materials electrically connected by an external circuit and physically separated by an ionic conducting layer (electrolyte layer). Electrochromic materials and devices can be controlled to change their color and opacity by the application of electrical stimuli. ECDs are a non-light emitting reflective technology. Materials for ECD manufacture can be taken into the form of printable inks and the manufacturing processes made compatible with standard graphic printing and converting processes. The resulting device can be made thin, flexible, transparent, robust, and ultra low-power. As ECDs can be produced into a wide range of different shapes and sizes, they offer a wide range of advantages for product design and integration.

Ynvisible R2R production line at Linkoping, Sweden

Fig.2 Electrochromic devices can be printed in sheet-to-sheet or roll-to-roll. 
Ynvisible Production R2R line in Linköping, Sweden.

R&D toward printed electrochromics began in the 1990s. In recent years, with strong advances in printed electronic and hybrid electronic systems, developments of ECDs have made strong technical progress into mass-manufacturability. Electrochromic displays and visual indicators are now entering markets that are considered “blue ocean” from the perspective of the electronic display industry. In these market spaces conventional printed products and surfaces now meet electronics. The over 800 billion USD per year printing industry, and particularly the industrial printing sub-sector, are welcoming printed electronic systems with high level of interest.

Things Alive

Today Ynvisible Interactive Inc. (“Ynvisible”) is leading the charge to bring printed electrochromics into market. Ynvisible was established with the vision to bring everyday objects and surfaces to life benefitting people in a smart and connected world. The company’s mission is to provide practical human interfaces to smart everyday objects and ambient intelligence.
After early explorations into different chromogenic systems the company focused on developing electrochromics into a mass producible, ultra-low power consuming visual interface technology. The company now develops and commercializes different printed electrochromic systems on film materials. By combining other printed electronic components and microelectronics into the electrochromic system, the company designs and produces interactive graphic solutions for everyday smart objects and surfaces.

Ynvisible aims to be the leading supplier of design tools, inks and quality control systems for the design and production of interactive printed graphics based on printed electrochromics and other printed electronics technologies. The company is building its technology and products platform under the ynvisible™ brand (ynvisible is a registered trademark in certain countries and territories).

Temperature label electrochromic displays, Ynvisible

Fig. 3 Electrochromic displays on a temperature label provide clear visual indication and are 
easy to implement – user friendly and available in high volumes.

Ynvisible’s primary focus is on applications in retail and logistics (where ECDs are printed onto RFID tags and RF-based smart labels), premium consumer brand products, and healthcare and wellness (in particular medical and diagnostic devices). Today the company offers a full services package to help product developers and designers get started with printed electrochromics. Ynvisible’s design, prototyping, customer training and sheet-to-sheet production services are based in Almada, Portugal. The company’s inks development and R&D services are based in Freiburg, Germany. In Linköping, Sweden the company operates a roll-to-roll production facility with extensive printing, converting, and quality control system capabilities. In addition to high volume ECD printing, the high capacity production line is utilized for printing of other printed electronic components and systems. Ynvisible sells printed electronics production upscaling services to other product owning companies.

Ynvisible Interactive Inc. is a publicly traded company, listed in the Toronto Stock Exchange Venture list [TSXV:YNV], the OTC Markets [OTCQB:YNVYF] and the Frankfurt Stock Exchange [FRA:1XNA]

Getting Started With Printed Electrochromics

To learn more about Printed Electrochromics, Ynvisible is hosting a free webinar on Apr 2, 2020 12:00-1:00 PM in Eastern Time (US and Canada). The one hour webinar includes speakers from the Georgia Institute of Technology, NXN-IP and the University of Lapland. To register see: https://www.ynvisible.com/events

Printed paper label - with NFC antenna and a printed electrochromic display, Ynvisible

Fig.4 Printed paper label with printed NFC antenna and printed electrochromic display on the same substrate.
A collaboration between Arjowiggins and Ynvisible.

Worldwide Industry for Electrochromic Materials to 2025 – Impact of COVID-19

https://www.globenewswire.com/news-release/2021/01/11/2156399/0/en/Worldwide-Industry-for-Electrochromic-Materials-to-2025-Impact-of-COVID-19.html

Electrochromic Materials Market Landscape

Technology launches, acquisitions, and R&D activities are key strategies adopted by players in the electrochromic materials market. In 2019, the market of electrochromic materials has been consolidated by the top ten players accounting for 65.4% of the share. Major players in the electrochromic materials market are Gentex corporation, Saint Gobain, View, Inc., ChromoGenics, AGC, Inc., Changzhou Yapu New Materials Co. Ltd., Magna Glass and Window Company Inc., Econtrol-Glass Gmbh & Co. KG, Nikon Corporation, and Zhuhai Kaivo Optoelectronic Technology Co. Ltd. among others.

  • Electrochromic Materials
    • Metal Oxides
    • Viologens
    • Conducting Polymers
    • Prussian Blue
    • Others
  • Electrochromic Materials Market
    • Automotive Rear View Mirrors
    • Smart Glass Windows
    • Displays
    • Others

https://www.alliedmarketresearch.com/electrochromic-glass-market

ElectroChromic Glass Markets

Region wise, the market is segmented into North America, Europe, Asia-Pacific, and LAMEA. Europe was the highest revenue contributor in 2019. The presence of leading automotive manufacturers using electrochromic glass is expected to drive the growth of the market. Electrochromic glasses yield better energy savings and comfort and are increasingly used in panoramic roofing in cars. It is already being used in Mercedes-Benz SLK and SL roadsters. Similarly, in 2019, AGP Group, one of the world’s leading glazing manufacturers, opened its automotive glazing plant in Belgium for producing panoramic roofs with electrochromic glass. This trend indicates a growing market for electrochromic glasses in automotive applications.

Smartphone manufacturers are developing phones containing electrochromic glasses to increase their share in the global electrochromic glass market share. For instance, at CES 2020, Chinese phone maker, OnePlus announced Concept One phone that uses electrochromic glasses to hide its rear triple cameras, when not in use. This phone is not expected to be mass produced but it opens a new end-use for electrochromic glass in the smartphone market, which is largely dominated by countries such as China, India, and Japan. Further, China is one of the world’s largest smartphone makers.  

The major electrochromic glass manufacturers analyzed in this report include AGC Inc., ChromoGenics AB, Compagnie de Saint-Gobain S.A., Hitachi Chemical Co. Ltd., Kinestral Technologies Inc., Pleotint LLC, Polytronix Inc., Research Frontiers Inc., Smartglass International Ltd., and View Inc. To stay competitive, these market players are adopting different strategies such as product launch, partnership, merger, and acquisition. For instance, on December 2017, AGC, Kinestral Technologies Inc. and G-Tech Optoelectronics Corp. announced a joint venture that will sell, distribute, and service Halio smart glasses to the global market. The new ventures are Halio North America, Halio International, and Halio China. The joint venture helped AGC to increase its market revenue. 

Multilayered ECD by Ricoh using CMY Colors

Source: Multi-Layered Electrochromic Display

Reflective Displays based on Conventional LCD
  • Reflective LCD
  • Japan Display Inc – MIP Reflective LCD
  • Samsung – SR (Super Reflectance) LCD Technology

Types of Reflective LCDs

  • Direct View
  • Projection

Japan Display Inc.

Japan Display Inc (JDI) is an LCD technology joint venture by Sony, Toshiba, and Hitachi since 2012.

Memory-in-pixel (MIP) Reflective Color LCD

Japan Display Inc. (JDI), a leading global supplier of small- and medium-sized displays, has announced the start of sales of a standard line-up of memory-in-pixel (MIP) reflective-type color LCD modules for wristwatch-type wearable devices which realize ultra-low power consumption. Power consumption of these reflective-type LCD modules is less than 0.5%*1 that of transparent-type LCD modules.

Source: Japan Display Inc.

Source: JAPAN DISPLAY SHOWS LOW-POWER REFLECTIVE LCD THAT DOES COLOR, VIDEO

Emerging Display Technologies

  • MIP Reflective Color LCD for Ultra Low Power Consumption
  • Organic Electro-Luminescent (EL) display for High Contrast and Thin Structure
  • Transparent Display
  • Light field display (LFD) for 3D Definition (Holographic)
  • Micro LED display
  • Hybrid OLED and Reflective LCD

Transflective LCD Displays

Transflective LCDs combine elements of both transmissive and reflective characteristics. Ambient light passes through the LCD and hits the semi-reflective layer. Most of the light is then reflected back through the LCD. However some of the light will not be reflected and will be lost. Alternately a backlight can be used to provide the light needed to illuminate the LCD if ambient light is low. Light from the backlight passes through a semi-reflective layer and illuminates the LCD. However as with ambient lighting some of the light does not penetrate the semi-reflective layer and is lost.

Depends both on Transmission and Reflection.

Types of Transflective LCDs

Source: Fundamentals of Liquid Crystal Devices

Based on the light modulation mechanisms, transflective LCDs can be classified into four categories:

  • absorption type
  • scattering type
  • reflection type
  • phase retardation type

https://pid.samsungdisplay.com/en/learning-center/blog/reflective-display-technology

https://pid.samsungdisplay.com/en/learning-center/blog/reflective-display-technology

Color-reflective LCD based on cholesteric liquid crystals
  • Kent Displays Inc.
  • Cholesteric liquid crystal (CLC)
  • Kent State University/Deng-Ke Yang

Cholesteric liquid crystals (hereafter Ch LCs) are self-assembled systems consisting of elongated chiral organic molecules. They possess a helical structure where the local average direction of the molecules twists spatially around an orthogonal helical axis. Their refractive index varies periodically, and thus exhibits a Bragg reflection band centered at the wavelength λ = [(ne + no)/2]P and with the bandwidth Δλ = (ne – no)P, where ne and no are the extraordinary and ordinary refractive indices of the LC, respectively, and P is the helical pitch. They can be used to make reflective displays which do not need polarizers and have high reflectance.

Dr. J. William Doane is a world renowned expert in the field of liquid crystal materials and devices. Together with William Manning he co-founded Kent Displays, Inc. in 1993 and the company is now famous for its Cholesteric LCD based Boogie Board writing tablets that use Dr Doane’s inventions. Dr. Doane, was the director of the world-renowned Liquid Crystal Institute at Kent State University from 1983-1996 and led the effort during that time to establish the National Science Foundation Center for Advanced Liquid Crystalline Optical Materials (ALCOM). As an active member of the international science community, he has held visiting appointments and maintained cooperative research programs in several countries. Dr. Doane was instrumental in formalizing the International Liquid Crystal Society and served as the organization’s first treasurer from 1990-1996. Dr. Doane was named a Fellow of the American Physical Society in 1982 and retired from the Kent State University in 1996 after a 31-year teaching and administrative career. Dr. Doane received the first ever presentation of the Slottow-Owaki Prize for Display Education, by SID.

Source: Bistable Liquid Crystal Displays

Cholesteric LCD Display

Source: Review Paper: A critical review of the present and future prospects for electronic paper

Reflective Displays Using Structural Colors

  • Interferometric Modulator Display (IMOD)
  • Photonic crystal displays (P-Ink)
  • Plasmonic Structural Colors Displays

Source: : E SKIN Displays

A wide range of reflective displays have recently been developed, and Fig. XX compares several of the most prominent. Much like color generation in animals, reflective displays can be separated into the same two main categories; pigmentation and structural color. Under the tent of pigmentation are products such as e-ink based “E-readers”, and color filter based liquid crystal displays. E-readers use the translocation of 3 charged pigmented beads, and as such, require seconds to switch between images. Due to the macroscopic size of each pixel, resolution and color reproduction are also limited. Reflective liquid crystal displays are much quicker, taking only milliseconds to switch states, but are limited in brightness as polarizers immediately halve the amplitude of the reflected light. Many structural color based displays are currently in development and have only recently entered the market. One such device is an interferometric modulator produced by Qualcomm where within each pixel, a cavity is formed between a Bragg stack and a MEMs mirror. By controlling the cavity spacing, the reflected light experiences either constructive or destructive interference resulting in a bright color or dark state. While producing the signature bright vivid colors of Bragg reflection, the device is inherently angle sensitive and limited to rigid substrates. Another emerging structural color based device uses a photonic crystal made from silica spheres submerged within an electro-active polymer, and is branded Photonic Ink (P-ink). The polymer stretches as a field is applied, increasing the period of the photonic crystal and therefore the wavelength of reflected light. Though the colors are vivid and tunable, the response time of the polymer is tens of seconds, making video impossible. Cholesteric and blue phase LC displays behave in a similar manner. Helixes of LC form periodic nanostructures which produce Bragg reflections at desired wavelengths. The LC structures can be switched through an external field thereby producing dark and light states. While producing vivid color, these devices are limited in brightness as the helical structures only reflect circular light of the same handedness of the LC. By assessing current technologies we determine there is much to understand and develop in order to truly mimic color generation in nature. A fast response, angle independent LC-metasurface based display which can actively shift the color of its pixels from RGB to black holds the promise for development of truly thin-film flexible displays.

Interferometric Modulator Display (IMOD)

(Structural Interference Colors)

  • Qualcomm Mirasol
  • MEMS Micro-Electro-Mechanical-Systems

MEMS Display

Source: Review Paper: A critical review of the present and future prospects for electronic paper

Source: Biological versus electronic adaptive coloration: how can one inform the other?

Photonic crystal displays (P-Ink)

(Structural Colors)

  • Opalux
  • Nanobrick

Photonic Crystals Display

Source: Review Paper: A critical review of the present and future prospects for electronic paper

Source: Review Paper: A critical review of the present and future prospects for electronic paper

Photonic crystals refer to a class of structures that consist of periodic nanostructures with a spacing that interacts with the propagation of electromagnetic waves. Based on the spacing of the nanostructures, certain energy bands are allowed or forbidden for propagation, which can lead to the selective transmission or reflection of light. Dynamically changing the spacing of the nanostructures can change these propagation properties, leading to the modulation necessary to build a display. The term photonic crystal in displays is usually associated with three-dimensional periodic lattices, and the previously described MEMS interferometry (Sec. 1) is a special one-dimensional case of a photonic crystal.

Currently, there are two different photonic-crystal- based modulation approaches in development. Opalux is fabricating electrically color-tunable photonic crystals by embedding the lattices of 200-nm-diameter silica beads within an expandable electroactive polymer, which they call Photonic Ink or P-Ink.142 Opalux has demonstrated bistable P-Ink with a reflectance >50% and switching speed ~0.1 sec.143 The company has not described the viewing-angle dependence of their technology; photonic-crystal structures that possess highly regular crystal structures can show sharp dependences on illumination and viewing angles.

The company Nanobrick is developing systems that control the inter-particle distance of SiOx-encapsulated metal nanoparticles (20–30 wt.%) in electrophoretic colloidal suspension.144 These photonic crystal structures respond to signals of a few volts, shifting the reflected color through a continuous range as the average spacing changes. This enables full-spectrum tunability using a single electro-optic layer without requiring individual primary-color subpixels to generate color. It appears that the electrophoresis tends to randomize the structure somewhat, leading to reasonably wide viewing angles. Nanobrick has demonstrated a Color Tunable Photonic Crystal Display (CPD) with angle-independent optical responses (0–40°) using quasi-amorphous photonic pixels with response time <50 msec.145

While single-layer color tuning is a unique capability of the photonic-crystal approaches, the technology focus thus far has been limited to unit pixel or simple segments and still needs refinement in terms of the white state, reflectance vs. illumination condition, and demonstration with matrix addressing. Even though, in theory, colors such as red can be displayed at all pixels, white is still challenged because white will likely require additive display of side-by-side RGB pixels [similar to Fig. 2(b)]. Additionally, since pixels currently do not possess inherent gray scale, that means gray scale at the display level will require halftoning approaches.

Source: Stretchable and reflective displays: materials, technologies and strategies

Source: Stretchable and reflective displays: materials, technologies and strategies

Source: P-Ink and Elast-Ink from lab to market

Plasmonic Structural Colors Displays

Source: Dynamic plasmonic color generation enabled by functional materials

Structural colors, well known from coloration in nature (7), can overcome these limitations. Different from dyes and pigments, structural colors are generated by the interaction of light with micro- and nanostructures. Vibrant colors can be produced with the same materials (e.g., metals or dielectrics) by changing the geometries, dimensions, or arrangements of the structures through the fabrication process or even after fabrication (8). Compared to pigment or dye-based coloration, colors created in this case are much brighter due to their inherently high scattering/absorption efficiencies. As a result, thin layers, or more precisely tiny volumes, are sufficient for brilliant coloration. The benefit of these small coloration volumes is obvious. Ultrahigh-resolution images composed of subwavelength pixels with sizes down to the smallest coloring unit, e.g., a single micro- or nanostructure, can be printed (9). In addition, structural colors do not fade over time but provide a basically everlasting coloration due to the stability of the coloring structures. These appealing advantages have attracted great interest and stimulated intensive research on various structural coloration schemes based on metal nanostructures, dielectric metasurfaces, photonic crystals, and Fabry-Perot (FP) resonances (61017).

Source: Plasmonic Color Makes a Comeback

Plasmonic color is a subset of structural color, which is color resulting when the micro- or nanostructure of a material causes light scattering and interference. One form of structural color is the iridescent blue of the Morpho butterfly’s wings, whose scales have branched nanostructures that scatter light in complex ways. In plasmonic color, the color arises from light absorption and scattering off of the nanoparticles themselves. As with other forms of structural color, size, shape, and patterning create the color rather than chemical composition.

Source: Plasmonic Color Makes a Comeback

The Naval Research Laboratory’s Fontana has a different approach to making dynamic plasmonic displays: using self- assembled colloidal gold nanorods suspended in toluene. By placing an electric field across the suspension, the nanorods align in the direction of the applied field, producing intense plasmonic color, Fontana explains. The system is fast; it can switch at least 1,000 times as quickly as a conventional liquid-crystal pixel, potentially cutting down on motion blur, which is a problem with LCD displays.

Source: Plasmonic Color Makes a Comeback

In current commercial displays, each pixel is actually made of a red, green, and blue subpixel. Different amounts of light from each subpixel mix to create the perception of any color desired. One ambition for those developing plasmonic color systems is to flip one pixel between red, green, and blue rather than needing three separate subpixels that would require less space, allowing for much smaller pixels and higher definition screens. A system that can do just that has been created in the lab of Jeremy Baumberg at the University of Cambridge. It uses gold nanoparticles coated in the conducting polymer polyaniline and sprayed onto a flexible mirrored surface. The mirrored surface amplifies the plasmonic resonance, resulting in a more intense, uniform color with no viewing-angle dependence.

The color of each pixel is tuned by the reversible oxidation and reduction of the polymer, which changes the polymer’s refractive index and shifts the system’s plasmonic resonance. Each nanoparticle can theoretically be tuned independently, providing a potential spatial resolution of less than 100 nm. So far, the researchers have created pixels that switch only between red and green, but they are working on blue. Silver or aluminum particles could potentially show blue color, but “there is always a trade- off, as silver and aluminum materials are chemically [more] unstable [than gold],” says Hyeon-Ho Jeong, who formerly worked as a postdoc with Baumberg at Cambridge and is now at Gwangju Institute of Science and Technology.

Key Terms

  • Plasmonic Metasurfaces
  • Plasmonic Nanostructures
  • Conjugated Polymers
  • Plasmons
  • Metallic Nanostructures
  • Functional Materials
  • Plasmonic Resonances
  • Liquid Crystals plus plasmonic nanostructure
  • Metal surface plasmonics
  • Nanowire waveguides
  • Meta-materials
  • Quantum dots (QDs)
  • Nano Hole Array NHA
  • Dielectric Metasurfaces
  • Tunable Color Filters
  • Metal-Insulator-Metal Resonators (MIM)
  • Sub Wavelength Grating SWG
  • Subwavelength metal–insulator–metal stack arrays
  • Nanowire Color Filter
  • Metasurface Color Filter
  • Quantum Dot Color Filter
  • Plasmonic hole array color filters

  • Debashis Chanda, a nanophotonics scientist at the University of Central Florida
  • E-skin Displays, in 2017

Source: Plasmonic Metasurfaces with Conjugated Polymers for Flexible Electronic Paper in Color

Transmissive Displays

Emmisive Displays
  • LED
  • True QLED
  • OLED
  • AM-OLED
  • Mini-LED
  • Micro LED

All QLED panels are made by Samsung. QLED really is LCD panel It requires back lighting.

All OLED panels are made by LG Displays.

Please see my post on LCD and LED displays.

Transmitive Displays
  • LCD
  • AM LCD
  • PMLCD

Please see my post on LCD and LED displays.

Transmissive liquid crystal displays (LCDs) have been widely used in laptop computers, desktop monitors, and high-definition televisions (HDTVs).

TFT- AMLCD

Source: Review of Display Technologies Focusing on Power Consumption

In AMLCD, a switch is placed at each pixel which decouples the pixel-selection function. Thin Film Transistor (TFT), the main technology of the AMLCD subgroup, can also be divided regarding the material used for its elaboration, into amorphous silicon (a-Si), continuous grain silicon (CGS) and low temperature polycrystalline silicon (LTPS TFT). A new approach is the indium-gallium-zinc- oxide (IGZO) technology developed by Sharp.

Another issue to take into account is the liquid crystal alignment mode, where Twisted Nematic (TN) and Super-Twisted Nematic (STN) types are the simplest and least expensive, but offering a poor viewing angle (of approx. 45 degrees). Vertical Alignment (VA) technology generally appears under various trade names (ASV by Sharp, PVA by Samsung, etc.) and tries to improve the viewing angle of the device (for instance, Ampire VA device offers 160 degrees versus the 45 of the TN device by AUO). In-plane switching (IPS TFT), as the Hitachi module from the table shows, also has a better viewing angle than TN and the color and contrast is also improved.

My related posts

On Light, Vision, Appearance, Color and Imaging

Digital Color and Imaging

Color and Imaging in Digital Video and Cinema

Shapes and Patterns in Nature

Growth and Form in Nature: Power Laws and Fractals

On Luminescence: Fluorescence, Phosphorescence, and Bioluminescence

Color Change: In Biology and Smart Pigments Technology

Optics of Metallic and Pearlescent Colors

Nature’s Fantastical Palette: Color From Structure

Color Science of Gem Stones

Color Science and Technology in LCD and LED Displays

Key Sources of Research

CLEARink

Waveshare

A Review of Electronic Paper Display Technologies from the Standpoint of SID Symposium Digests

Tatsumi Takahashi

TCL NXTPAPER wants to compete against E INK

September 3, 2020 By Michael Kozlowski 

Review of Paper-Like Display Technologies

Peng Fei Bai1, Robert A. Hayes1, Ming Liang Jin1, Ling Ling Shui1, Zi Chuan Yi1, L. Wang1, Xiao Zhang1, and Guo Fu Zhou1, 2

Progress In Electromagnetics Research, Vol. 147, 95–116, 2014

Stretchable and reflective displays: materials, technologies and strategies

Nano Convergence volume 6, Article number: 21 (2019)

https://nanoconvergencejournal.springeropen.com/articles/10.1186/s40580-019-0190-5

Review Paper: A critical review of the present and future prospects for electronic paper

Jason Heikenfeld (SID Senior Member) Paul Drzaic (SID Fellow)
Jong-Souk Yeo (SID Member)
Tim Koch (SID Member)

Journal of the SID 19/2, 2011

Electrowetting-Based Displays: Bringing Microfluidics Alive On-Screen

B. J. Feenstra1, R. A. Hayes, R. van Dijk, R. G. H. Boom, M. M. H. Wagemans, I. G. J. Camps, A. Gi- raldo and B. v.d. Heijden
Philips Research Laboratories, Prof. Holstlaan 4, 5656 AA, Eindhoven, The Netherlands

Biological versus electronic adaptive coloration: how can one inform the other?

Eric Kreit1, Lydia M. Ma ̈thger2, Roger T. Hanlon2, Patrick B. Dennis3, Rajesh R. Naik3, Eric Forsythe4 and Jason Heikenfeld1

J R Soc Interface 10: 20120601.

https://royalsocietypublishing.org/doi/pdf/10.1098/rsif.2012.0601

Transmissive/Reflective Structural Color Filters: Theory and Applications


Yan Yu,1,2 Long Wen,2 Shichao Song,2 and Qin Chen

Volume 2014 |Article ID 212637 | https://doi.org/10.1155/2014/212637

https://www.hindawi.com/journals/jnm/2014/212637/

Interferometric modulator display

https://en.wikipedia.org/wiki/Interferometric_modulator_display

Qualcomm resurrects Mirasol reflective displays with new 576 ppi smartphone panel

https://www.theverge.com/2013/5/22/4354642/high-res-mirasol-display-for-smartphones-demonstrated

Iridescence-controlled and flexibly tunable retroreflective structural color film for smart displays

  • Wen Fan
  • Jing Zeng
  • Qiaoqiang Gan
  • Dengxin Ji
  • Haomin Song
  • Wenzhe Liu
  • Lei Shi
  • Limin Wu

Science Advances  09 Aug 2019:
Vol. 5, no. 8, eaaw8755
DOI: 10.1126/sciadv.aaw8755

https://advances.sciencemag.org/content/advances/5/8/eaaw8755.full.pdf

Artificial Structural Color Pixels: A Review 

by Yuqian Zhao 1Yong Zhao 1,*Sheng Hu 1Jiangtao Lv 1Yu Ying 2Gediminas Gervinskas 3 and Guangyuan Si 

Materials 201710(8), 944; https://doi.org/10.3390/ma10080944

https://www.mdpi.com/1996-1944/10/8/944/htm

Dynamically Tunable Plasmonic Structural Color

Daniel Franklin
University of Central Florida 2018

PHD Thesis

https://stars.library.ucf.edu/cgi/viewcontent.cgi?article=6880u0026amp;context=etd

Colors with plasmonic nanostructures: A full-spectrum review 

Applied Physics Reviews 6, 041308 (2019); https://doi.org/10.1063/1.5110051

https://aip.scitation.org/doi/abs/10.1063/1.5110051?journalCode=are

Dynamic plasmonic color generation enabled by functional materials

Frank Neubrech1,2, Xiaoyang Duan1,2, Na Liu3,4*

Bright and Vivid Diffractive–Plasmonic Reflective Filters for Color Generation

  • Emerson G. Melo, 
  • Ana L. A. Ribeiro, 
  • Rodrigo S. Benevides, 
  • Antonio A. G. V. Zuben, 
  • Marcos V. Puydinger dos Santos, 
  • Alexandre A. Silva, 
  • Gustavo S. Wiederhecker, and 
  • Thiago P. M. Alegre*

ACS Appl. Nano Mater. 2020, 3, 2, 1111–1117Publication Date:December 31, 2019 https://doi.org/10.1021/acsanm.9b02508

https://pubs.acs.org/doi/full/10.1021/acsanm.9b02508

Active control of plasmonic colors: emerging display technologies

Kunli Xiong, Daniel Tordera, Magnus Jonsson and Andreas B. Dahlin

Rep Prog Phys. 2019 Feb;82(2):024501.

doi: 10.1088/1361-6633/aaf844.

https://pubmed.ncbi.nlm.nih.gov/30640724/

Self-assembled plasmonics for angle-independent structural color displays with actively addressed black states

Daniel Franklina,b, Ziqian Hec, Pamela Mastranzo Ortegab, Alireza Safaeia,b, Pablo Cencillo-Abadb, Shin-Tson Wuc, and Debashis Chandaa,b,c,1

https://www.pnas.org/content/117/24/13350

Bio-inspired intelligent structural color materials

Luoran Shang, Weixia Zhang, Ke Xuc and Yuanjin Zhao

Mater. Horiz., 2019,6, 945-958 

https://pubs.rsc.org/en/content/articlelanding/2019/mh/c9mh00101h#!divAbstract

Advanced Plasmonic Materials for Dynamic Color Display

DOI: 10.1002/adma.201704338

https://www.researchgate.net/publication/320997060_Advanced_Plasmonic_Materials_for_Dynamic_Color_Display

Polarization-independent actively tunable colour generation on imprinted plasmonic surfaces

Nature Communications volume 6, Article number: 7337 (2015)

https://www.nature.com/articles/ncomms8337

Tunable plasmonic color filter 

Rosanna Mastria, Karl Jonas Riisnaes, Monica Craciun, and Saverio Russo

Frontiers in Optics / Laser Science OSA Technical Digest (Optical Society of America, 2020),paper JTh4B.7•

https://doi.org/10.1364/FIO.2020.JTh4B.7

https://www.osapublishing.org/abstract.cfm?uri=FiO-2020-JTh4B.7

Reflective Display Technology

Samsung 2017

https://pid.samsungdisplay.com/en/learning-center/blog/reflective-display-technology

Modeling of Oil/Water Interfacial Dynamics in Three-Dimensional Bistable Electrowetting Display Pixels

Guisong Yang, Lei Zhuang, Pengfei Bai,* Biao Tang, Alex Henzen, and Guofu Zhou

CS Omega 2020, 5, 10, 5326–5333Publication Date:March 3, 2020https://doi.org/10.1021/acsomega.9b04352

https://pubs.acs.org/doi/10.1021/acsomega.9b04352

The E-Paper Revolution Has Begun

Mon, September 09, 2019

https://www.radiantvisionsystems.com/blog/e-paper-revolution-has-begun

Global E-Paper Display Market Growth Prospects, Key Vendors, Future Scenario Forecast To 2027 | CLEARink Displays, Inc., E Ink Holdings Inc

07-07-2020

https://www.openpr.com/news/2086154/global-e-paper-display-market-growth-prospects-key-vendors

e-Paper Display Markets 2016-2024: e-Readers, Signage/Poster Devices, Mobile Phones, & Others – Global Analysis, Trends, and Forecasts Report 2019

2019

https://www.globenewswire.com/news-release/2019/05/31/1860959/0/en/e-Paper-Display-Markets-2016-2024-e-Readers-Signage-Poster-Devices-Mobile-Phones-Others-Global-Analysis-Trends-and-Forecasts-Report-2019.html

Worldwide E-Paper Display Market Share, Growth, Statistics, by Application, Production, Revenue & Forecast up to 2027

https://www.mccourier.com/worldwide-e-paper-display-market-share-growth-statistics-by-application-production-revenue-forecast-up-to-2027/

Clearink Displays

https://www.clearinkdisplays.com/about-us

What Happened to Liquavista Electrowetting Display?

https://lookgadgets.com/liquavista/

Etulipa brings its electrowetting display off-the-grid

23 October 2019
BART BROUWERS

How Electronic Ink Was Invented

OLED vs. LED: Which kind of TV display is better?

By Michael Bizzaco Simon Cohen and Tyler LacomaJanuary 21, 2021

https://www.digitaltrends.com/home-theater/oled-vs-led/

E-INK AND E-PAPER: A HISTORY, ROOM SIGNS AND MORE

https://www.visix.com/resources/blog/e-ink-and-e-paper-a-history-room-signs-and-more/

11 Myths About E-paper Displays

https://www.electronicdesign.com/technologies/embedded-revolution/article/21805149/11-myths-about-epaper-displays

Good E Reader.com

https://goodereader.com/blog/

DKE E PAPER Manufacturer

E Ink.com

Pervasive Displays

https://www.pervasivedisplays.com

World’s Largest ePaper E Ink Sign Unveiled at UN Headquarters

https://www.mpicosys.com/news/worlds-largest-epaper-e-ink-sign-unveiled-un-headquarters/

ONYX BOOX

https://www.boox.com

Plastic Logic

E Paper Displays Explained

E Ink, Innolux deliver 28-inch ePaper

https://www.digitalsignagetoday.com/news/e-ink-innolux-deliver-28-inch-epaper/

E Ink and Plastic Logic Partner to Provide the World’s First Flexible Advanced Color ePaper (ACeP™)-Based Display

https://www.businesswire.com/news/home/20201203005052/en/E-Ink-and-Plastic-Logic-Partner-to-Provide-the-World’s-First-Flexible-Advanced-Color-ePaper-ACeP™–Based-Display

Ossia, E-PEAS, and E Ink Debut E-Paper Electronic Shelf Label Powered by Wireless Energy Harvesting

July 28, 2019 by Scott McMahan

https://eepower.com/news/ossia-e-peas-and-e-ink-debut-e-paper-electronic-shelf-label-powered-by-wireless-energy-harvesting/#

PicoSign

Visionect and E Ink Launch Prototyping System for Developing Large-Format ePaper Signs

the-ebook-reader.com

https://www.the-ebook-reader.com/e-ink.html

Electronic Ink

http://www2.units.it/ramponi/teaching/DIP/materiale/z04_disp_e-ink.pdf

E -Ink

https://www.eink.com/

Invited Paper: TFT Technologies for Flexible Displays

Jin Jang Min Hee Choi Jun Hyuk Cheon

First published: 05 July 2012 

https://doi.org/10.1889/1.3499860

https://onlinelibrary.wiley.com/doi/abs/10.1889/1.3499860

A Review In Preparation of Electronic Ink for Electrophoretic Displays

S.KholghiEshkalak*, M.Khatibzadeh

PROCEEDINGS OF THE INTERNATIONAL CONFERENCE NANOMATERIALS:APPLICATIONS AND PROPERTIES

Vol.3 No2,02 NAESF06 (5pp)(2014)

https://core.ac.uk/reader/141442140

Flexible Electronics Development in Taiwan

Dr. Janglin (John) Chen
Vice President & General Director Display Technology Center

ITRI

2010

TFT Technology for Flexible Display Applications

Chang-Dong Kim, In Byeong Kang, and In-Jae Chung

LCD R&D Center, LG.Philips LCD, 533, Hogae-dong, Dongan-gu, Anyang-shi, Kyoungki-do, 431-080, KOREA

Progress and Challenges in Commercialization of Organic Electronics

Yueh-Lin Loo and Iain McCulloch, Guest Editors

MRS BULLETIN • VOLUME 33 • JULY 2008

Evaluating Display Reflections in Reflective Displays and Beyond

https://onlinelibrary.wiley.com/doi/pdf/10.1002/msid.1099

Active Matrix Electrophoretic E-Book Display

Guofu Zhouand Mark Johnson
Philips Research, High Tech Campus, Building 34, Eindhoven 5656 AE, The Netherlands

Karl Amundson and Robert W Zehner
E Ink Corporation, 733 Concord Avenue, Cambridge, MA 02138 USA

Alex Henzen and Jan van de Kamer
IRex Technologies BV, High Tech Campus, Building 46, Eindhoven 5656 AE, The Netherlands

Inkjet-printed polymer-based electrochromic and electrofluorochromic dual-mode displays†

Manuel Pietsch, Tobias Rödlmeier, Stefan Schlisske

Johannes Zimmermann, Carlos Romero-Nieto and Gerardo Hernandez-Sosa

J. Mater. Chem. C, 2019, 7, 7121

https://pubs.rsc.org/en/content/articlehtml/2019/tc/c9tc01344j

Invited Paper: International Standards Development of Electronic Paper Displays

Tatsumi Takahashi

First published: 29 May 2019

SID Volume50, Issue1
June 2019
Pages 398-401

https://onlinelibrary.wiley.com/doi/abs/10.1002/sdtp.12941

Dyed Polymeric Microparticles for Colour Rendering in Electrophoretic Displays

Mark Goulding, Louise Farrand, Ashley Smith, Nils Greinert, Henry Wilson, Claire Topping, Roger Kemp, Emily Markham, Mark James, Johannes Canisius, Dan Walker
Merck Chemicals Ltd., Advanced Technologies, Chilworth Technical Centre, University Parkway, Southampton, Hampshire, SO16 7QD, UK

Richard Vidal, Sihame Khoukh

Merck Chimie, Center Production ESTAPOR, Zone Industrielle, Rue du Moulin de la Canne, 45 300 Pithiviers, France.

Seung-Eun Lee, Hee-Kyu Lee

Merck Advanced Technologies, Poseung Technical Center, 1173-2 Wonjyung-ri, Poseung-myun, Pyungtaek-si, Kyungki-do, Korea

E-paper Display (EPD) Market Size 2020-2024 Industry News Analysis, Upstream Raw Material Suppliers, Major Players and Product Types

2020

https://www.wfmj.com/story/42526423/e-paper-display-epd-market-size-2020-2024-industry-news-analysis-upstream-raw-material-suppliers-major-players-and-product-types

E Ink Holdings, electronic ink technology, and Fujitsu Semiconductor have developed a reference design board for battery-less ePaper tags using E Ink’s ePaper and Fujitsu’s UHF (Ultra High Frequency) band.

Printing Technologies for Organic TFT Array for Electronic Paper

Ryohei Matsubara, Yukari Harada, Kaoru Hatta,

Takumi Yamamoto, Manabu Takei, Mamoru Ishizaki,

Mitsuyoshi Matsumura, Kenich Ota, and Manabu Ito

Display Research Laboratory, Technical Research Institute, Toppan Printing Co., Ltd., Saitama, Japan

CYM and RGB colored electronic inks based on silica-coated organic pigments for full-color electrophoretic displays 

Peipei Yin,aGang Wu,*aWenlong Qin,aXiaoqiang Chen,aMang Wanga  and  Hongzheng Chen*a

https://pubs.rsc.org/no/content/articlelanding/2013/tc/c2tc00344a/unauth#!divAbstract

Hisense A7CC 5G smartphone integrates a 6.7-inch color E-Ink display

Bistable electrowetting displays

Karlheinz Blankenbach

Juergen Rawert

January 2011
DOI: 10.1117/2.1201012.003407

https://www.researchgate.net/publication/315169299_Bistable_electrowetting_displays

Current commercialization status of electrowetting-on-dielectric (EWOD) digital microfluidics

Jia Li and Chang-Jin “CJ” Kim

Lab Chip, 2020,20, 1705-1712 

https://pubs.rsc.org/en/content/articlelanding/2020/lc/d0lc00144a/unauth#!divAbstract

The complete history of E INK Color E-Paper

November 22, 2020 

A Short History of E-Paper and the eReader Revolution

August 11, 2017 By Michael Kozlowski

https://goodereader.com/blog/electronic-readers/a-short-history-of-e-ink-and-the-ereader-revolution

A Short History of E-Ink: How E Ink managed to become the last man standing and dominated the e-reader revolution!

by Michael Kozlowski

book

2018

Electrochromic Plasmonic Metasurfaces for Reflective Displays 

By Kunli Xiong

2017

https://core.ac.uk/display/128708224

Switching Colors with Electricity

BY  ROGER J. MORTIMER

https://www.americanscientist.org/article/switching-colors-with-electricity

MicroLED vs OLED: the battle of the high-end display tech

Can the next-gen TV tech microLED beat out OLED?

https://www.techradar.com/news/microled-vs-oled-the-battle-of-the-high-end-display-tech

OLED vs QLED: the premium TV panel technologies compared

https://www.techradar.com/news/oled-vs-qled

LG’s new ‘QNED’ TVs will have up to nearly 30,000 tiny LEDs behind the screen

The Verge

https://www.theverge.com/2020/12/28/22203910/lg-qned-mini-led-4k-8k-lcd-tv-announced-ces-2021

Performance of reflective color displays in Out Of Home applications

ETulipa

Plasmonic Color Makes a Comeback

ACS Cent. Sci. 2020, 6, 332−335

https://pubs.acs.org/doi/pdf/10.1021/acscentsci.0c00259

Structural Colors for Display and E-paper Applications

L. Jay Guo

Department of Electrical Engineering and Computer Science The University of Michigan, Ann Arbor, Michigan, USA

https://deepblue.lib.umich.edu/bitstream/handle/2027.42/107993/sdtp00205.pdf;jsessionid=4ECB722ACF8896CFECA475935B750BD0?sequence=1

Stretchable and reflective displays: materials, technologies and strategies

Nano Convergence volume 6, Article number: 21 (2019)

https://nanoconvergencejournal.springeropen.com/articles/10.1186/s40580-019-0190-5

Transmissive/Reflective structural color filters: theory and applications

Journal of Nanomaterials January 2014 Article No.: 6 https://doi.org/10.1155/2014/212637

https://dl.acm.org/doi/abs/10.1155/2014/212637

https://dl.acm.org/doi/pdf/10.1155/2014/212637

Plasmonic Metasurfaces with Conjugated Polymers for Flexible Electronic Paper in Color

Kunli Xiong, Gustav Emilsson, Ali Maziz, Xinxin Yang, Lei Shao, Edwin W. H. Jager and Andreas B. Dahlin.

Reflective–emissive photoluminescent cholesteric liquid crystal display

Jang-Kyum Kim, Suk-Hwan Joo, and Jang-Kun Song

Applied OpticsVol. 52,Issue 34,pp. 8280-8286(2013)

Mobile Displays: Technology and Applications

edited by Achintya K. Bhowmik, Zili Li, Philip J. Bos

Book

Reflective cholesteric liquid crystal displays

D.-K. Yang Kent State Univ

in Mobile Displays,

Reflective and Transflective Liquid Crystal Displays

  • September 2014

DOI: 10.1002/9781118751992.ch9

  • In book: Fundamentals of Liquid Crystal Devices, Second Edition (pp.285-319)

Deng‐Ke Yang
Shin-Tson Wu

Full-color reflective display based on narrow bandwidth templated cholesteric liquid crystal film

DOI: 10.1364/OME.7.000016

https://www.researchgate.net/publication/311358302_Full-color_reflective_display_based_on_narrow_bandwidth_templated_cholesteric_liquid_crystal_film

Electrophoretic liquid crystal displays: How far are we?

Susanne Klein

HP Laboratories HPL-2013-23

How Liquid Crystal Displays Work in an eWriter

By Monica Kanojia May 04, 2012

https://www.livescience.com/20104-boogie-board-ewriter-nsf-bts.html

Dynamic plasmonic color generation enabled by functional materials

  1. Frank Neubrech
  2. Xiaoyang Duan
  3. Na Liu

Science Advances  04 Sep 2020:
Vol. 6, no. 36, eabc2709
DOI: 10.1126/sciadv.abc2709

https://advances.sciencemag.org/content/6/36/eabc2709

Reflective Liquid Crystal Displays

Shin-Tson Wu, Hughes Research Laboratories
Deng-ke Yang, Kent State University

The evolution of portable communications applications has been facilitated largely by the development of reflective LCD technology. Offering a unique insight into state-of-the art display technologies, Reflective Liquid Crystal Displays covers the basic operations principles, exemplary device structures and fundamental material properties of device components.

Featuring:

  • Direct-view, projection and micro (virtual projection) reflective displays in the context of multi-media projectors, mobile internet and personal entertainment displays.
  • Optimization of critical display attributes: fast response time, low voltage operation and wide angle viewing.
  • Description of the basic properties of liquid crystal materials and their incorporation into configurations for transmissive and reflective applications.
  • Examination of the various operations modes enabling the reader to select the appropriate display type to meet a variety of needs.
  • Overview and comparison of the complete range of reflective display technologies, and reflective LCD effects.

Product Demographics
Author:    Shin-Tson Wu, Deng-Ke Yang
Publisher:    John Wiley & Sons, Ltd
Date of Publication:    04/01/2001
ISBN Number:    0-471-49611-1
Format:    Hardback
Pages:    352

Reflective liquid crystal display with fast response time and wide viewing angle

Xiao-Qing GuaFan ChuaLi-Lan TianaRui LiaWen-Yi HouaXiang-Yu Zhoua Qiong-HuaWang

Received 29 August 2019, Revised 5 November 2019, Accepted 16 November 2019, Available online 20 November 2019.

Optics Communications. Volume 459, 15 March 2020, 124970

https://www.sciencedirect.com/science/article/abs/pii/S0030401819310466

RDot AB ElectroChromic Displays

https://rdotdisplays.com/displays

Review of nanostructure color filters Felix Gildas and Yaping Dan*

University of Michigan–Shanghai Jiao Tong University Joint Institute, Shanghai, China

J. Nanophoton. 13(2), 020901 (2019), doi: 10.1117/1.JNP.13.020901.

http://yapingd.sjtu.edu.cn/upload/editor/file/20190708/20190708084242_36263.pdf

Nanostructured Color Filters: A Review of Recent Developments

Ayesha Shaukat 1,2 , Frazer Noble and Khalid Mahmood Arif 1,*

Received: 21 June 2020; Accepted: 23 July 2020; Published: 7 August 2020

Liquid-crystal tunable color filters based on aluminum metasurfaces

Zu-Wen Xie, Jhen-Hong Yang, Vishal Vashistha, Wei Lee, and Kuo-Ping Chen

 Optics Express > Volume 25 > Issue 24 > Page 30764

Structural Colors: From Plasmonic to Carbon Nanostructures

Ting XuHaofei ShiYi‐Kuei WuAlex F. KaplanJong G. OkL. Jay Guo

First published: 20 September 2011 

Small, 7, 3128 (2011)

https://doi.org/10.1002/smll.201101068

https://www.semanticscholar.org/paper/Structural-colors%3A-from-plasmonic-to-carbon-Xu-Shi/53a8c9085eec0bf86300a1feb54004c7085b2448

A New Full Color Reflective Display Based on Cholesteric Liquid Crystals

https://www.displaydaily.com/paid-news/ldm-mdm/technology/a-new-full-color-reflective-display-based-on-cholesteric-liquid-crystals

Reflective Display Technology 

22 Dec 2017 Samsung

https://pid.samsungdisplay.com/en/learning-center/blog/reflective-display-technology

Electrochromic Displays

Kobayashi N. (2015)

In: Chen J., Cranton W., Fihn M. (eds) Handbook of Visual Display Technology. Springer, Berlin, Heidelberg.

https://doi.org/10.1007/978-3-642-35947-7_188-1

Transparent inorganic multicolour displays enabled by zinc-based electrochromic devices

Light: Science & Applicationsvolume 9, Article number: 121 (2020) 

https://www.nature.com/articles/s41377-020-00366-9

Electrochromic Device

https://www.sciencedirect.com/topics/materials-science/electrochromic-device

What is an Electrochromic Display?

Ynvisible

https://www.ynvisible.com/news-inspiration/what-is-an-electrochromic-display

Rollable and transparent subpixelated electrochromic displays using deformable nanowire electrodes with improved electrochemical and mechanical stability

Jong-WooKimDo-KyunKwonJae-MinMyoung

Department of Materials Science and Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea

Received 22 November 2019, Revised 26 December 2019, Accepted 15 January 2020, Available online 18 January 2020.

https://doi.org/10.1016/j.cej.2020.124145

https://www.sciencedirect.com/science/article/abs/pii/S1385894720301364

Performance studies of electrochromic displays

Proceedings Volume 9258, Advanced Topics in Optoelectronics, Microelectronics, and Nanotechnologies VII; 925833 (2015)

https://doi.org/10.1117/12.2072317

https://www.spiedigitallibrary.org/conference-proceedings-of-spie/9258/1/Performance-studies-of-electrochromic-displays/10.1117/12.2072317.short?SSO=1

Flexible and Transparent Electrochromic Displays with Simultaneously Implementable Subpixelated Ion Gel‐Based Viologens by Multiple Patterning

Jong‐Woo KimJae‐Min Myoung

First published: 04 February 2019 

https://doi.org/10.1002/adfm.201808911

https://onlinelibrary.wiley.com/doi/abs/10.1002/adfm.201808911

Greyscale and Paper Electrochromic Polymer Displays by UV Patterning 

by Robert Brooke 1,2Jesper Edberg 1,2Xavier Crispin 1Magnus Berggren 1Isak Engquist 1 and Magnus P. Jonsson 1,*1

Laboratory of Organic Electronics, Department of Science and Technology, Linkoping University, SE-601 74 Norrkoping, Sweden2RISE Acreo, ICT Department, Printed Electronics, Research Institutes of Sweden, Acreo, 601 17 Norrkoping, Sweden

 Polymers201911(2), 267; https://doi.org/10.3390/polym11020267

https://www.mdpi.com/2073-4360/11/2/267

Printed Electrochromics boldly goes where no display has gone before

Ron Mertens

https://www.oled-info.com/printed-electrochromics-boldly-goes-where-no-display-has-gone

Multi-Layered Electrochromic Display

Yoshihisa Naijoh, Tohru Yashiro, Shigenobu Hirano, Yoshinori Okada, SukChan Kim, Kazuaki Tsuji, Hiroyuki Takahashi, Koh Fujimura, Hitoshi Kondoh

RICOH Company, Ltd., Research and Development Group, 16-1 Shinei-cho, Tsuzuki-ku, Yokohama-shi, Kanagawa, Japan

High Resolution Technology for Multi-Layered Electrochromic Display

Yoshinori Okada, Tohru Yashiro, Yoshihisa Naijoh, Shigenobu Hirano, SukChan Kim, Kazuaki Tsuji, Hiroyuki Takahashi, Koh Fujimura, Hitoshi Kondoh

RICOH Company, Ltd., Research and Development Group, 16-1 Shinei-cho, Tsuzuki-ku, Yokohama, Kanagawa, Japan

Flexible Electrochromic Display

Tohru Yashiro, Yoshinori Okada, Yoshihisa Naijoh, Shigenobu Hirano, Toshiya Sagisaka, Daisuke Gotoh, Mamiko Inoue, SukChan Kim, Kazuaki Tsuji, Hiroyuki Takahashi, and Koh Fujimura

RICOH Company, Ltd., Research and Development Group, 16-1 Shinei-cho, Tsuzuki-ku, Yokohama, Kanagawa, Japan

5.3: Novel Design for Color Electrochromic Display

Tohru Yashiro, Shigenobu Hirano, Yoshihisa Naijoh, Yoshinori Okada, Kazuaki Tsuji, Mikiko Abe, Akishige Murakami, Hiroyuki Takahashi, Koh Fujimura, Hitoshi Kondoh

Ricoh Company, Ltd.Research and Development Group 16-1 Shinei-cho, Tsuzuki-ku Yokohama, Kanagawa, Japan

Electrokinetic pixels with biprimary inks for color displays and color-temperature-tunable smart windows

S. MUKHERJEE,1 W. L. HSIEH,3 N. SMITH,2 M. GOULDING,2 AND J. HEIKENFELD1,*

1Department of Electrical Engineering and Computing Systems, University of Cincinnati, Cincinnati, Ohio 45221, USA 2Merck Chemicals Ltd., Chilworth Technical Centre, Southampton, Hampshire SO16 7QD, UK
3Institute of Applied Mechanics, National Taiwan University, Taipei 106, Taiwan
*Corresponding author: heikenjc@ucmail.uc.edu

Received 11 March 2015; revised 5 May 2015; accepted 11 May 2015; posted 18 May 2015 (Doc. ID 235176); published 10 June 2015

Vol. 54, No. 17 / June 10 2015 / Applied Optics

TransPrint: A Method for Fabricating Flexible Transparent Free-Form Displays


Walther Jensen,1 Ashley Colley,2 Jonna Häkkilä,2 Carlos Pinheiro,3 and Markus Löchtefeld1

1Aalborg University, 9000 Aalborg, Denmark

2University of Lapland, 96300 Rovaniemi, Finland

3Ynvisible Interactive Inc., 2820-690 Charneca da Caparica, Portugal

Advances in Human-Computer Interaction, vol. 2019, Article ID 1340182, 14 pages,2019. https://doi.org/10.1155/2019/1340182

https://www.hindawi.com/journals/ahci/2019/1340182/

IllumiPaper: Illuminated Interactive Paper

Konstantin Klamka, Raimund Dachselt

Interactive Media Lab Dresden Technische Universita ̈t Dresden, Germany {klamka, dachselt}@acm.org

Electrofluidic Imaging Films for Brighter, Faster, and Lower‐Cost e‐Paper

Matthew Hagedon Jason Heikenfeld Kenneth A. Dean Eric Kreit Kaichang Zhou John Rudolph

First published: 01 July 2013

SID

Volume44, Issue1 June 2013 Pages 111-114

https://doi.org/10.1002/j.2168-0159.2013.tb06154.x

https://onlinelibrary.wiley.com/doi/abs/10.1002/j.2168-0159.2013.tb06154.x

The Biprimary Color System for E‐Paper: Doubling Color Performance Compared to RGBW

Sayantika Mukherjee Jason Heikenfeld Nathan Smith Mark Goulding Claire Topping Sarah Norman Qin Liu Laura Kramer

Volume45, Issue1 San Diego, CA, June 1–6, 2014
June 2014 Pages 869-872. First published: 07 July 2014

https://doi.org/10.1002/j.2168-0159.2014.tb00229.x

https://onlinelibrary.wiley.com/doi/abs/10.1002/j.2168-0159.2014.tb00229.x

Fundamentals and Applications of Large Area Multi-spectral state Electrophoretic Panels for Displays and Smart Windows

PhD Thesis 2015

Sayantika Mukherjee

Printed Multi-color Devices using Oxidative Electrochromic Materials

Daisuke Goto*, Satoshi Yamamoto, Toshiya Sagisaka, Masato Shinoda, Fuminari Kaneko, Keiichiro Yutani, Keigo Takauji, Yoshinori Okada, and Tohru Yashiro

Ricoh Institute of Future Technology, Ricoh Co., Ltd.
16-1 Shinei-cho, Tsuduki-ku, Yokohama, Kanagawa 224-0035, Japan

*daisuke.dg.gotoh@nts.ricoh.co.jp

Journal of Photopolymer Science and Technology

Volume 30, Number 4 (2017) 489-493 

https://www.jstage.jst.go.jp/article/photopolymer/30/4/30_489/_pdf

Novel organic multi-color electrochromic device for e-paper application

Authors: Kobayashi, Norihisa; Yukikawa, Masahiro; Liang, Zhuang; Nakamura, Kazuki
Source: NIP & Digital Fabrication Conference, Volume 2017, Number 1, November 2017, pp. 111-114(4)
Publisher: Society for Imaging Science and Technology

https://www.ingentaconnect.com/contentone/ist/nipdf/2017/00002017/00000001/art00026

Scalable electrochromic nanopixels using plasmonics

  1. Jialong Peng
  2. Hyeon-Ho Jeong
  3. Qianqi Lin
  4. Sean Cormier1
  5. Hsin-Ling Liang2
  6. Michael F. L. De Volder2
  7. Silvia Vignolini3 and 
  8. Jeremy J. Baumberg1,
  1. 1NanoPhotonics Centre, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, UK.
  2. 2NanoManufacturing Group, Department of Engineering, University of Cambridge, Cambridge CB3 0FS, UK.
  3. 3Bio-inspired Photonics Group, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK.

Science Advances  10 May 2019:
Vol. 5, no. 5, eaaw2205
DOI: 10.1126/sciadv.aaw2205

https://advances.sciencemag.org/content/5/5/eaaw2205

Electrochromic display

Innoscentia adopts Ynvisible displays for dynamic food labels

https://www.e-ink-info.com/tags/electrochromic-display

Low energy switching driver for printed electrochromic displays

Ciprian Ionescu, Robert Alexandru Dobre

Proceedings Volume 10010, Advanced Topics in Optoelectronics, Microelectronics, and Nanotechnologies VIII; 100100I (2016) https://doi.org/10.1117/12.2246104

Event: Advanced Topics in Optoelectronics, Microelectronics, and Nanotechnologies 2016, 2016, Constanta, Romania

https://www.spiedigitallibrary.org/conference-proceedings-of-spie/10010/1/Low-energy-switching-driver-for-printed-electrochromic-displays/10.1117/12.2246104.short

Electrochromic materials and devices: present and future 

Prakash R. Somani a,∗, S. Radhakrishnan b

Photonics and Advanced Materials Laboratory, Centre for Materials for Electronics Technology (C-MET), Panchawati, Off Pashan Road, Pune 411008, India
National Chemical Laboratory (NCL), Polymer Science and Chemical Engineering, Pune 411008, India

Received 17 May 2001; received in revised form 10 September 2001; accepted 26 September 2001

Materials Chemistry and Physics 77 (2002) 117–133

A high speed electrically switching reflective structural color display with large color gamut

Wenqiang Wang,aZhiqiang Guan *a  and  Hongxing Xu*ab

Nanoscale, 2021,13, 1164-1171 

https://pubs.rsc.org/en/content/articlelanding/2021/nr/d0nr07347d/unauth#!divAbstract

Mechanochromism in Structurally Colored Polymeric Materials

Jess M. Clough,* Christoph Weder, and Stephen Schrettl

Macromol. Rapid Commun. 202142, 2000528

https://onlinelibrary.wiley.com/doi/full/10.1002/marc.202000528

Transparent inorganic multicolour displays enabled by zinc-based electrochromic devices

by Light Publishing Center, Changchun Institute of Optics, Fine Mechanics And Physics, Chinese Academy

https://phys.org/news/2020-07-transparent-inorganic-multicolour-enabled-zinc-based.html

Transparent inorganic multicolour displays enabled by zinc-based electrochromic devices

Light: Science & Applications volume 9, Article number: 121 (2020)

https://www.nature.com/articles/s41377-020-00366-9

The Rdot Display

https://rdotdisplays.com/displays#technology-overview

Flexible displays for smart clothing: Part II— Electrochromic displays

Ludivine MeunierFern M. Kelly,  V. Koncar

Published 2011

https://www.semanticscholar.org/paper/Flexible-displays-for-smart-clothing%3A-Part-II—-Meunier-Kelly/416ae224096d852d4e804f023344cfd77f8a0955

Electrochromic displays

The new black

Nature Materials volume 7, pages766–767(2008)

https://www.nature.com/articles/nmat2282

Intrinsically stretchable polymer based electrochromic devices for soft electronic displays

Preston, Garth Eden Claire

2020 PhD Thesis UBC, Canada

https://open.library.ubc.ca/cIRcle/collections/ubctheses/24/items/1.0394053

TiO2 Nanostructured Films for Electrochromic Paper Based-Devices

by Daniela Nunes , Tomas Freire, Andrea Barranger 1, João Vieira 1, Mariana Matias 1, Sonia Pereira 1, Ana Pimentel 1, Neusmar J. A. Cordeiro 1,2, Elvira Fortunato 1 and Rodrigo Martins 1,

Appl. Sci. 2020, 10(4), 1200; https://doi.org/10.3390/app10041200

https://www.mdpi.com/2076-3417/10/4/1200/htm

Printable All‐Organic Electrochromic Active‐Matrix Displays

P. Andersson R. Forchheimer P. Tehrani M. Berggren
First published: 31 August 2007

https://doi.org/10.1002/adfm.200601241

Advanced Functional Materials Volume17, Issue16
November, 2007
Pages 3074-3082

https://onlinelibrary.wiley.com/doi/epdf/10.1002/adfm.200601241

Development and Manufacture of Polymer‐Based Electrochromic Devices

Jacob Jensen Markus Hösel Aubrey L. Dyer Frederik C. Krebs

Advanced Functional Materials Volume25, Issue14
April 8, 2015
Pages 2073-2090

First published: 26 February 2015 https://doi.org/10.1002/adfm.201403765

https://onlinelibrary.wiley.com/doi/abs/10.1002/adfm.201403765

In-Glass Display Applications

Lumineq

Greyscale and Paper Electrochromic Polymer Displays by UV Patterning 

by Robert Brooke 1,2Jesper Edberg 1,2Xavier Crispin 1Magnus Berggren 1Isak Engquist 1 and Magnus P. Jonsson 1,*1

Laboratory of Organic Electronics, Department of Science and Technology, Linkoping University, SE-601 74 Norrkoping, Sweden2

RISE Acreo, ICT Department, Printed Electronics, Research Institutes of Sweden, Acreo, 601 17 Norrkoping, Sweden

 

Polymers 201911(2), 267; https://doi.org/10.3390/polym11020267

https://www.mdpi.com/2073-4360/11/2/267

Ynvisible

https://www.ynvisible.com/products

Novel Color-Sequential Transflective Liquid Crystal Displays 

Ju-Hyun Lee, Xinyu Zhu, and Shin-Tson Wu, Fellow, IEEE

JOURNAL OF DISPLAY TECHNOLOGY, VOL. 3, NO. 1, MARCH 2007

Control of Reflectivity and Bistability in Displays Using Cholesteric Liquid-Crystals

Deng-Ke Yang

Kent State University – Kent Campus

John L. West

Kent State University – Kent Campus

Liang-Chy Chien
Kent State University – Kent Campus, lchien@kent.edu

J. William Doane

Kent State University – Kent Campus

1994

Journal of Applied Physics 76(2), 1331-1333. doi: 10.1063/1.358518

A Polymer-Stabilized Single-Layer Color Cholesteric Liquid Crystal Display with Anisotropic Reflection. 

Lu, Shin-Ying and Chien, Liang-Chy (2007).

Applied Physics Letters 91(13). doi: 10.1063/1.2790499

Electrofluidic Imaging Films for Brighter, Faster, and Lower‐Cost e‐Paper

Matthew HagedonJason HeikenfeldKenneth A. DeanEric KreitKaichang ZhouJohn Rudolph

First published: 01 July 2013 

https://doi.org/10.1002/j.2168-0159.2013.tb06154.x

SID Digest Volume44, Issue1
June 2013
Pages 111-114

https://onlinelibrary.wiley.com/doi/abs/10.1002/j.2168-0159.2013.tb06154.x

POLYMER STABILIZED BLACK-WHITE CHOLESTERIC REFLECTIVE DISPLAY

Inventors:Deng-KeYang, Hudson; Ruiqing Ma, Kent, both of Ohio

Asigne:Kent State University, Kent, Ohio

Patent Number: 5,847,798

Date of Patent: Dec.8,1998

BISTABLE POLYMER DISPERSED CHOLESTERIC LIQUID CRYSTAL DISPLAYS

Inventors:Deng-KeYang, Stow,Ohio;

Zhijian Lu,Yorktown Heights, N.Y.;

J.William Doane, Kent, Ohio

Assignee: Kent State University, Kent, Ohio

Patent Number: 6,061,107

Date of Patent: May9,2000

HOLOGRAPHICALLY FORMED REFLECTIVE DISPLAY, LIQUID CRYSTAL DISPLAY AND PROJECTION SYSTEM AND METHODS OF FORMING THE SAME

Inventors: Louis D.Silverstein, Scotsdale, Ariz.,

Thomas G. Fiske, Campbell, Calif.;

Greg P. Crawford, Providence, R.I.

Assignee: Xerox Corporation, Stamford, Conn.

Patent Number: 6,133,971

Date of Patent: Oct.17,2000

Japan Display shows low-power reflective LCD that does color, video

https://www.engadget.com/2012-11-05-japan-display-shows-low-power-reflective-lcd.html

Japan Display Introduces Paper-like Color Reflective LCD

https://www.cdrinfo.com/d7/content/japan-display-introduces-paper-color-reflective-lcd

https://www.hardwarezone.com.sg/tech-news-japan-display-showcases-7-inch-paper-reflective-lcd-panel

Overview on reflective liquid crystal displays using one polarizer

Shin-Tson Wu

Proceedings Volume 3421, Display Technologies II; (1998) https://doi.org/10.1117/12.311049
Event: Asia Pacific Symposium on Optoelectronics ’98, 1998, Taipei, Taiwan

https://www.spiedigitallibrary.org/conference-proceedings-of-spie/3421/0000/Overview-on-reflective-liquid-crystal-displays-using-one-polarizer/10.1117/12.311049.short?SSO=1

Reflective Liquid-Crystal Displays

Published online by Cambridge University Press:  31 January 2011

Tatsuo Uchida  and Takahiro Ishinabe

MRS Bulletin , Volume 27 , Issue 11: Advanced Flat-Panel Displays and Materials , November 2002 , pp. 876 – 879

DOI: https://doi.org/10.1557/mrs2002.276

https://www.cambridge.org/core/journals/mrs-bulletin/article/abs/reflective-liquidcrystal-displays/61677377AAC957316F367A6B4612E0A1

Reflective Liquid Crystal Displays

Shin-Tson Wu, Hughes Research Laboratories
Deng-ke Yang, Kent State University

The evolution of portable communications applications has been facilitated largely by the development of reflective LCD technology. Offering a unique insight into state-of-the art display technologies, Reflective Liquid Crystal Displays covers the basic operations principles, exemplary device structures and fundamental material properties of device components.

Display engineers, scientists and technicians active in the field will welcome this unique resource, as will developers of a wide range of systems and applications. Graduate students and researchers will appreciated the introduction and technical insight into this exciting technology.

Featuring:

  • Direct-view, projection and micro (virtual projection) reflective displays in the context of multi-media projectors, mobile internet and personal entertainment displays.
  • Optimization of critical display attributes: fast response time, low voltage operation and wide angle viewing.
  • Description of the basic properties of liquid crystal materials and their incorporation into configurations for transmissive and reflective applications.
  • Examination of the various operations modes enabling the reader to select the appropriate display type to meet a variety of needs.
  • Overview and comparison of the complete range of reflective display technologies, and reflective LCD effects.


Author:    Shin-Tson Wu, Deng-Ke Yang
Publisher:    John Wiley & Sons, Ltd
Date of Publication:    04/01/2001
ISBN Number:    0-471-49611-1
Format:    Hardback
Pages:    352

https://www.sid.org/Publications/Bookstore/tabid/836/c/book/p/reflective-liquid-crystal-displays/Default.aspx

Reflective liquid crystal display with fast response time and wide viewing angle

Xiao-QingGuaFanChuaLi-LanTianaRuiLiaWen-YiHouaXiang-YuZhouaQiong-HuaWangb

Optics Communications
Volume 459, 15 March 2020, 124970

https://www.sciencedirect.com/science/article/abs/pii/S0030401819310466

TRANSPARENT REFLECTIVE LIQUID CRYSTAL DISPLAY

Inventors:Jong Weon Moon, Seoul (KR);Yong Beom Kim, Seoul (KR)

US202/089623A1

July 2002

What LCD Modes Mean: Reflective, Transmissive, Transflective

March 14, 2017

Reflective Liquid Crystal Displays: The Next Major Paradigm Shift in Display Technology

Gregory P. Crawford Brown University, Providence, RI

Power generating reflective-type liquid crystal displays using a reflective polariser and a polymer solar cell. 

Ho Huh, Y. and Park, B.

Sci. Rep. 5, 11558; doi: 10.1038/srep11558 (2015).

https://www.nature.com/articles/srep11558

Achromatic Dye-type Polarizer for Paper White Reflective Liquid Crystal Displays

ITE Trans. on MTA Vol. 6, No. 4, pp. 262-268 (2018)

Noriaki Mochizuki†1, Takahiro Ishinabe†2 (member), Daichi Fujiwara†3, Daisuke Nakamura†3, Norio Koma†3, Hideo Fujikake†2 (member)

https://www.jstage.jst.go.jp/article/mta/6/4/6_262/_article/-char/en

Types of LCD Displays

https://www.eeeguide.com/types-of-lcd-displays/

Reflective LCD Display:

https://www.eeeguide.com/reflective-lcd-display/

Color OLED/reflective LCD hybrid display can be easily seen in full sunlight

Display demoed at SID 2016 is suitable in size for a cell phone.

Jun 27th, 2016

https://www.laserfocusworld.com/detectors-imaging/article/16558979/color-oledreflective-lcd-hybrid-display-can-be-easily-seen-in-full-sunlight

Reflective LCD Display

Sun Vision Display

https://www.sunvisiondisplay.com/technology

FLEx Lighting Sets Out to Transform Reflective LCD

https://www.displaysupplychain.com/blog/flex-lighting-sets-out-to-transform-reflective-lcd

Reflective liquid crystal display using cholesteric polymers

US-0883021 (2001-06-15)

JDI Reflective Display is For Digital Signage

https://www.displaydaily.com/paid-news/ldm/ldm-event-reports/ldm-company-event-reports/jdi-shows-reflective-display-for-digital-signage

Japan Display Inc. to start mass production of ultra-low power consumption Memory-In-Pixel reflective-type LCD module

Posted By itersnews On January 13, 2014 

http://itersnews.com/?p=64732

MONOCHROME AND COLOR MEMORY-IN-PIXEL DISPLAYS (MIP)

https://www.data-modul.com/en/displays/mip-displays.html

Reflective liquid-crystal displays with asymmetric incident and exit angles

Zhibing Ge, Thomas X. Wu, Xinyu Zhu, and Shin-Tson Wu

Journal of the Optical Society of America A Vol. 22, Issue 5, pp. 966-977 (2005) •https://doi.org/10.1364/JOSAA.22.000966

https://www.researchgate.net/publication/7842095_Reflective_liquid-crystal_displays_with_asymmetric_incident_and_exit_angles

Analyses and Improvements of Whiteness of Reflective Liquid Crystal Displays

Yi-Pai Huang1, Liang-San Chu1 and Han-Ping D. Shieh1

Published 9 September 2004 • Copyright (c) 2004 The Japan Society of Applied Physics
Japanese Journal of Applied PhysicsVolume 43Number 9R

Citation Yi-Pai Huang et al 2004 Jpn. J. Appl. Phys. 43 6162

Reflective liquid-crystal display using an in-plane-switching super-twisted nematic cell

Y. SunHong-mei Ma, +1 author S. Wu

Published 2002

Journal of Applied Physics

https://www.semanticscholar.org/paper/Reflective-liquid-crystal-display-using-an-nematic-Sun-Ma/51d4591feb27bad6fe47d5ceb7872a0de2c4b79d

Color Reflective Display Technology

Ricoh

https://www.ricoh.com/technology/tech/031_epaper

Liquid Crystal Display (LCD) Modes

Hitachi

http://www.koe.j-display.com/upload/file/AN-005_Display_Modes.pdf

Review of Display Technologies Focusing on Power Consumption

María Rodríguez Fernández 1,†, Eduardo Zalama Casanova 2,* and Ignacio González Alonso 3,†

Sustainability 2015, 7, 10854-10875; doi:10.3390/su70810854

Fujitsu Dramatically Enhances Color Electronic Paper Functionality

https://www.fujitsu.com/global/about/resources/news/press-releases/2010/0507-01.html

https://en.wikipedia.org/wiki/FLEPia

What are ZBD LCDs?

December 19, 2019

New Vision Display Acquires ZBD LCD Technology and Malvern, UK Facility

https://www.displaydaily.com/article/press-releases/new-vision-display-acquires-zbd-lcd-technology-and-malvern-uk-facility

Large Area, High Resolution Portable ZBD Display

DOI: 10.1889/1.1830238

https://www.researchgate.net/publication/250999021_51_Large_Area_High_Resolution_Portable_ZBD_Display

Nemoptic OLED/BiNem combo display gets video demo

Chris Davies – Oct 11, 2010, 4:12am CDT

https://www.slashgear.com/nemoptic-oledbinem-combo-display-gets-video-demo-11107018/

https://www.oled-info.com/nemoptic-unvies-oled-coupled-bistable-nematic-lcd-display

https://www.sii.co.jp/en/news/release/2008/12/04/10150/

Bistable Reflective LCDs

https://focuslcds.com/journals/bistable-display-new-custom-lcd-technology-qa/

Bistable Liquid Crystal Displays

  • January 2016
  • Cliff Jones

DOI: 10.1007/978-3-319-14346-0_92

https://www.researchgate.net/publication/310481389_Bistable_Liquid_Crystal_Displays

The Zenithal Bistable Display: From concept to consumer

DOI: 10.1889/1.2835021

https://www.researchgate.net/publication/245414219_The_Zenithal_Bistable_Display_From_concept_to_consumer

A Nematic-Cholesteric Bistable Liquid Crystal Display For Projectors

A. MochizukiM. IwasakiY. YamagishiH. GondoH. Yamaguchi

Global Bistable LCD Market: Industry Analysis 2013-2018 and Opportunity Assessment 2018-2023

https://industryresearchcity.wordpress.com/2019/05/22/global-bistable-lcd-market-industry-analysis-2013-2018-and-opportunity-assessment-2018-2023/

CLEARink Displays

https://www.clearinkdisplays.com

Recent Trend of Display Devices

Fumiaki Funada*1 Masaya Hijikigawa*2

1997

Electrofluidic Displays: Multi-stability and Display Technology Progress

Kenneth A. Dean, Kaichang Zhou, Steve Smith, Brian Brollier, Hari Atkuri and John Rudolph
Gamma Dynamics, Cincinnati, OH 45229, U.S.A.

Shu Yang, Stephanie Chevalliot, Eric Kreit, and Jason Heikenfeld

Novel Devices Lab, University of Cincinnati, Cincinnati, OH 45221, U.S.A.

Photonic-crystal full-colour displays

́
ANDRE C. ARSENAULT1,2*, DANIEL P. PUZZO1,2, IAN MANNERS3* AND GEOFFREY A. OZIN1*

1Department of Chemistry, University of Toronto, 80 St George Street, Toronto M5S 3H6, Canada 2Opalux Incorporated, 80 St George Street, Toronto M5S 3H6, Canada
3School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, UK
*e-mail: andre.arsenault@opalux.com; Ian.Manners@bristol.ac.uk; gozin@chem.utoronto.ca

nature photonics | VOL 1 | AUGUST 2007 | www.nature.com/naturephotonics

P-Ink displays: Flexible, low power, reflective color

Andre C ArsenaultHai WangEric HendersonFergal KerinsUlrich KampLeonardo Da Silva BonifacioPak Hin LawGeoffrey A. Ozin

Proceedings Volume 8613, Advanced Fabrication Technologies for Micro/Nano Optics and Photonics VI; 86130R (2013) 

https://doi.org/10.1117/12.2006468
Event: SPIE MOEMS-MEMS, 2013, San Francisco, California, United States

https://www.spiedigitallibrary.org/conference-proceedings-of-spie/8613/86130R/P-Ink-displays-Flexible-low-power-reflective-color/10.1117/12.2006468.short

P-Ink and Elast-Ink from lab to market

Geoffrey A.OzinaAndre C.Arsenaultba

Center for Inorganic and Polymeric Nanomaterials, Chemistry Department, University of Toronto, 80 St George Street, Toronto, Ontario, Canada M5S3H6b

Opalux Incorporated, 80 St George Street, Toronto, Ontario, Canada M5S 3H6

Materials Today Volume 11, Issues 7–8, July–August 2008, Pages 44-51

https://www.sciencedirect.com/science/article/pii/S1369702108701482

A Polychromic, Fast Response Metallopolymer Gel Photonic Crystal with Solvent and Redox Tunability: A Step Towards Photonic Ink (P‐Ink)

A.C. Arsenault. H. Míguez V. Kitaev G.A. Ozin I. Manners

First published: 20 March 2003 

https://doi.org/10.1002/adma.200390116

https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.200390116

Nanobrick

http://www.nanobrick.co.kr/en/home_en

Opalux

ESKIN Displays

http://www.eskindisplays.com

Structural Colors: From Plasmonic to Carbon Nanostructures

Ting Xu, Haofei Shi, Yi-Kuei Wu, Alex F. Kaplan, Jong G. Ok, and L. Jay Guo

http://oknano.org/doc/paper/international/012_2011_Small_structuralcolors_review.pdf

Liquid-crystal tunable color filters based on aluminum metasurfaces

ZU-WEN XIE,1 JHEN-HONG YANG,2 VISHAL VASHISTHA,3 WEI LEE,4 AND KUO-PING CHEN4,*

1Institute of Lighting and Energy Photonics, National Chiao Tung University, Guiren Dist, Tainan 71150, Taiwan
2Institute of Photonic System, National Chiao Tung University, Guiren Dist., Tainan 711, Taiwan 3Faculty of Physics, Adam Mickiewicz University in Poznan, Poland

4Institute of Imaging and Biomedical Photonics, National Chiao Tung University, Guiren Dist., Tainan 71150, Taiwan

Full-Color Realization of Micro-LED Displays 

Yifan Wu, Jianshe Ma, Ping Su * , Lijun Zhang and Bizhong Xia

Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; wuyf19@mails.tsinghua.edu.cn (Y.W.); ma.jianshe@sz.tsinghua.edu.cn (J.M.); zhanglj18@mails.tsinghua.edu.cn (L.Z.); xiabz@sz.tsinghua.edu.cn (B.X.)
Correspondence: su.ping@sz.tsinghua.edu.cn

Nanomaterials 202010, 2482; doi:10.3390/nano10122482

Plasmonic Color Makes a Comeback

Rachel Brazil

ACS Central Science 2020 6 (3), 332-335 DOI: 10.1021/acscentsci.0c00259

https://pubs.acs.org/doi/pdf/10.1021/acscentsci.0c00259

Plasmonic Metasurfaces with Conjugated Polymers for Flexible Electronic Paper in Color

Kunli Xiong, Gustav Emilsson, Ali Maziz, Xinxin Yang, Lei Shao, Edwin Jager and Andreas B. Dahlin

Advanced Materials, 2016. 28(45), pp.9956-9960. http://dx.doi.org/10.1002/adma.201603358

Dynamic plasmonic color generation enabled by functional materials


Frank Neubrech1,2, Xiaoyang Duan1,2, Na Liu3,4*

Neubrech et al., Sci. Adv. 2020; : eabc2709 4 September 2020

Scalable electrochromic nanopixels using plasmonics

Jialong Peng1*, Hyeon-Ho Jeong1*, Qianqi Lin1, Sean Cormier1, Hsin-Ling Liang2, Michael F. L. De Volder2, Silvia Vignolini3, Jeremy J. Baumberg1†

Peng et al., Sci. Adv. 2019;5:eaaw2205 10 May 2019

Actively addressed single pixel full-colour plasmonic display


Daniel Franklin1,2, Russell Frank2, Shin-Tson Wu3 & Debashis Chanda1,2,3

2016

NATURE COMMUNICATIONS | 8:15209 | DOI: 10.1038/ncomms15209 | http://www.nature.com/naturecommunications

https://www.nature.com/articles/ncomms15209.pdf?origin=ppub

Super Ultra-High Resolution Liquid-Crystal-Display Using Perovskite Quantum-Dot Functional Color-Filters

Scientific Reports volume 8, Article number: 12881 (2018)

https://www.nature.com/articles/s41598-018-30742-w

Micro-light-emitting diodes with quantum dots in display technology

Light: Science & Applicationsvolume 9, Article number: 83 (2020)

https://www.nature.com/articles/s41377-020-0268-1

Plasmonic Color Filters for CMOS Image Sensor Applications

Sozo Yokogawa,†,‡,§ Stanley P. Burgos,†,§ and Harry A. Atwater*,†
†Thomas J. Watson Laboratories of Applied Physics, California Institute of Technology, Pasadena, California 91125, United States

‡Sony Corporation, Atsugi Tec. 4-14-1 Asahi-cho, Atsugi, Kanagawa, 243-0014, Japan

dx.doi.org/10.1021/nl302110z | Nano Lett.

Review of nanostructure color filters 

Felix Gildas and Yaping Dan*

University of Michigan–Shanghai Jiao Tong University Joint Institute, Shanghai, China

Journal of Nanophotonics 020901-1 Apr–Jun 2019 • Vol. 13(2)

http://yapingd.sjtu.edu.cn/upload/editor/file/20190708/20190708084242_36263.pdf

Electroactive Inverse Opal: A Single Material for All Colors

Daniel P. PuzzoAndre C. ArsenaultIan MannersGeoffrey A. Ozin

First published: 13 January 2009 

https://doi.org/10.1002/anie.200804391

Angewandte Volume48, Issue5 January 19, 2009 Pages 943-947

https://onlinelibrary.wiley.com/doi/epdf/10.1002/anie.200804391

Electrically tunable block copolymer photonic crystals with a full color display

Yijie Lu,a Hongwei Xia,a Guangzhao Zhang*a and Chi Wuab

Received 23rd March 2009, Accepted 3rd June 2009
First published as an Advance Article on the web 30th June 2009 DOI: 10.1039/b905760a

J. Mater. Chem., 2009, 19, 5952–5955

DYNAMICALLY TUNABLE PLASMONIC STRUCTURAL COLOR

by

DANIEL FRANKLIN
B.S. Missouri University of Science and Technology, 2011

A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy
in the Department of Physics
in the College of Sciences
at the University of Central Florida
Orlando, Florida

Spring Term 2018

Major Professor: Debashis Chanda

http://etd.fcla.edu/CF/CFE0007001/Franklin_Thesis.pdf

Progress in polydopamine-based melanin mimetic materials for structural color generation

Michinari Kohri

Department of Applied Chemistry and Biotechnology, Graduate School of Engineering, Chiba University, Chiba, Japan

SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS 2021, VOL. 21, NO. 1, 833–848 https://doi.org/10.1080/14686996.2020.1852057

https://pubmed.ncbi.nlm.nih.gov/33536837/

Photoresponsive Structural Color in Liquid Crystalline Materials

Michael E. McConneyMariacristina RumiNicholas P. GodmanUrice N. TohghaTimothy J. Bunning

First published: 24 May 2019 https://doi.org/10.1002/adom.201900429

Adv Optical Materials Volume7, Issue16
Special Issue: Light‐Responsive Smart Soft Matter Technologies
August 19, 2019
1900429

https://onlinelibrary.wiley.com/doi/abs/10.1002/adom.201900429

Liquid-crystal materials find a new order in biomedical applications

Scott J Woltman 1Gregory D JayGregory P Crawford

Nat Mater
. 2007 Dec;6(12):929-38. doi: 10.1038/nmat2010. Epub 2007 Nov 18.

https://pubmed.ncbi.nlm.nih.gov/18026108/

Color Science and Technology in LCD and LED Displays

Color Science and Technology in LCD and LED Displays

Key Terms

  • Liquid Crystals Display (LCD)
  • Light Emitting Diodes (LED)
  • Organic LED (OLED)
  • Active Matrix (AM)
  • Active Matrix OLED (AMOLED)
  • Quantum light-emitting diode (QLED)
  • Quantum Dot LED
  • Quantum dots nanorod LED (QNED)
  • Mini LED
  • Micro LED
  • Color Filters (CFA)
  • Backlighting
  • Liquid Crystals
  • Light Polarization
  • Pixels
  • Sub-Pixels
  • RGB (Red Green Blue)
  • White Light
  • Blue LEDs
  • Flat Panel Display
  • CRT (Cathode Ray Tube)
  • Phosphores
  • Pigments
  • Thin Film Transistors (TFT)
  • Active Matrix TFT
  • Twisted Nematic (TN)
  • In Panel Switching displays (IPS Panels)
  • Vertical Alignment Panels (VA Panels)
  • Advanced Fringe Field Switching (AFFS)
  • AM-LCD
  • Plasma based Displays
  • CCFL Fluorescent Lamps
  • Flexible Displays
  • FPD Flat Panel Display
  • QD-OLED
  • QD-LCD
  • White LEDs
  • RGB LED Lighting
  • White LED Lighting
  • QDEF Quantum Dot Enhanced Film
  • LCM LC Module
  • QD-CF QD Color Filter
  • QD-LED based on Electroluminescence
  • miniLED Backlit LCD
  • Mini/Micro LED Emissive Displays
  • Linear Polarizer in LCD
  • Circular Polarizer in OLED
  • Perovskite LEDs
  • GB-R LED Green Blue LED + Red Phosphor
  • RB – G LED Red Blue LED + Green Phosphor
  • WCG-CCFL
  • Color Resist
  • Photo Mask
  • Optical Film
  • Neo QLED (mini LED)
  • HDR and Rec.2020 compliant displays
  • Adobe RGB Color Space
  • Rec 709 Color Space
  • DCI P3 Color Space
  • Rec 2020 Color Space
  • Color Gamut
  • Contrast Ratio
  • Brightness
  • Luminescence
  • High Dynamic Range HDR
  • Color Volume
  • Chromaticity
  • 1pc-WLED Phosphor Converted White LED
  • 2pc-WLED Phosphor Converted White LED
  • Color Crosstalk
  • Blue LED-pumped red and green QDs backlight
  • Color Converted Film CCF
  • Luminance
  • GaN – Gallium Nitride
  • lnGaN
  • Colloidal Semiconductor QDs
  • Semiconductor nanocrystal quantum-dot-integrated white- light-emitting diodes (QD-WLEDs)
  • (Low Temperature PolySilicon LCD) LTPS LCD
  • Poly-silicon (poly-Si)
  • Amorphous silicon (a-Si)
  • Organic–inorganic perovskite (OIP)
  • Photo Resist

LCD (Liquid Crystal Display)

Definition

LCD (Liquid Crystal Display) is a type of flat panel display which uses liquid crystals in its primary form of operation. LEDs have a large and varying set of use cases for consumers and businesses, as they can be commonly found in smartphones, televisions, computer monitors and instrument panels.

LCDs were a big leap in terms of the technology they replaced, which include light-emitting diode (LED) and gas-plasma displays. LCDs allowed displays to be much thinner than cathode ray tube (CRT) technology. LCDs consume much less power than LED and gas-display displays because they work on the principle of blocking light rather than emitting it. Where an LED emits light, the liquid crystals in an LCD produces an image using a backlight.

As LCDs have replaced older display technologies, LCDs have begun being replaced by new display technologies such as OLEDs.

How LCDs work

A display is made up of millions of pixels. The quality of a display commonly refers to the number of pixels; for example, a 4K display is made up of 3840 x2160 or 4096×2160 pixels. A pixel is made up of three subpixels; a red, blue and green—commonly called RGB. When the subpixels in a pixel change color combinations, a different color can be produced. With all the pixels on a display working together, the display can make millions of different colors. When the pixels are rapidly switched on and off, a picture is created.

The way a pixel is controlled is different in each type of display; CRT, LED, LCD and newer types of displays all control pixels differently. In short, LCDs are lit by a backlight, and pixels are switched on and off electronically while using liquid crystals to rotate polarized light. A polarizing glass filter is placed in front and behind all the pixels, the front filter is placed at 90 degrees. In between both filters are the liquid crystals, which can be electronically switched on and off.

 LCDs are made with either a passive matrix or an active matrix display grid. The active matrix LCD is also known as a thin film transistor (TFT) display. The passive matrix LCD has a grid of conductors with pixels located at each intersection in the grid. A current is sent across two conductors on the grid to control the light for any pixel. An active matrix has a transistor located at each pixel intersection, requiring less current to control the luminance of a pixel. For this reason, the current in an active matrix display can be switched on and off more frequently, improving the screen refresh time.

Some passive matrix LCD’s have dual scanning, meaning that they scan the grid twice with current in the same time that it took for one scan in the original technology. However, active matrix is still a superior technology out of the two.

Types of LCDs

Types of LCDs include:

  • Twisted Nematic (TN)- which are inexpensive while having high response times. However, TN displays have low contrast ratios, viewing angles and color contrasts.
  • In Panel Switching displays (IPS Panels)- which boast much better contrast ratios, viewing angles and color contrast when compared to TN LCDs.
  • Vertical Alignment Panels (VA Panels)- which are seen as a medium quality between TN and IPS displays.
  • Advanced Fringe Field Switching (AFFS)- which is a top performer compared IPS displays in color reproduction range.

LCD vs OLED vs QLED

LCDs are now being outpaced by other display technologies, but are not completely left in the past. Steadily, LCDs have been being replaced by OLEDs, or organic light-emitting diodes.

 OLEDs use a single glass or plastic panels, compared to LCDs which use two. Because an OLED does not need a backlight like an LCD, OLED devices such as televisions are typically much thinner, and have much deeper blacks, as each pixel in an OLED display is individually lit. If the display is mostly black in an LCD screen, but only a small portion needs to be lit, the whole back panel is still lit, leading to light leakage on the front of the display. An OLED screen avoids this, along with having better contrast and viewing angles and less power consumption. With a plastic panel, an OLED display can be bent and folded over itself and still operate. This can be seen in smartphones, such as the controversial Galaxy Fold; or in the iPhone X, which will bend the bottom of the display over itself so the display’s ribbon cable can reach in towards the phone, eliminating the need for a bottom bezel.

However, OLED displays tend to be more expensive and can suffer from burn-in, as plasma-based displays do.

QLED stands for quantum light-emitting diode and quantum dot LED. QLED displays were developed by Samsung and can be found in newer televisions. QLEDs work most similarly to LCDs, and can still be considered as a type of LCD. QLEDs add a layer of quantum dot film to an LCD, which increases the color and brightness dramatically compared to other LCDs. The quantum dot film is made up of small crystal semi-conductor particles. The crystal semi-conductor particles can be controlled for their color output. 

When deciding between a QLED and an OLED display, QLEDs have much more brightness and aren’t affected by burn-in. However, OLED displays still have a better contrast ratio and deeper blacks than QLEDs.

This was last updated in September 2019

Source: https://www.thoughtco.com/liquid-crystal-display-history-lcd-1992078

The History of Liquid Crystal Display

By Mary Bellis Updated March 02, 2019

hudiemm/Getty Images

An LCD or liquid crystal display is a type of flat panel display commonly used in digital devices, for example, digital clocks, appliance displays, and portable computers.

How an LCD Works 

Liquid crystals are liquid chemicals whose molecules can be aligned precisely when subjected to electrical fields, much in the way metal shavings line up in the field of a magnet. When properly aligned, the liquid crystals allow light to pass through.

A simple monochrome LCD display has two sheets of polarizing material with a liquid crystal solution sandwiched between them. Electricity is applied to the solution and causes the crystals to align in patterns. Each crystal, therefore, is either opaque or transparent, forming the numbers or text that we can read. 

History of Liquid Crystal Displays 

In 1888, liquid crystals were first discovered in cholesterol extracted from carrots by Austrian botanist and chemist, Friedrich Reinitzer.

In 1962, RCA researcher Richard Williams generated stripe patterns in a thin layer of liquid crystal material by the application of a voltage. This effect is based on an electrohydrodynamic instability forming what is now called “Williams domains” inside the liquid crystal.

According to the IEEE, “Between 1964 and 1968, at the RCA David Sarnoff Research Center in Princeton, New Jersey, a team of engineers and scientists led by George Heilmeier with Louis Zanoni and Lucian Barton, devised a method for electronic control of light reflected from liquid crystals and demonstrated the first liquid crystal display. Their work launched a global industry that now produces millions of LCDs.”

Heilmeier’s liquid crystal displays used what he called DSM or dynamic scattering method, wherein an electrical charge is applied which rearranges the molecules so that they scatter light.

The DSM design worked poorly and proved to be too power hungry and was replaced by an improved version, which used the twisted nematic field effect of liquid crystals invented by James Fergason in 1969.

James Fergason 

Inventor James Fergason holds some of the fundamental patents in liquid crystal displays filed in the early 1970s, including key US patent number 3,731,986 for “Display Devices Utilizing Liquid Crystal Light Modulation”

In 1972, the International Liquid Crystal Company (ILIXCO) owned by James Fergason produced the first modern LCD watch based on James Fergason’s patent.

Liquid Crystals in a Display

Source: Japan Display Inc.

LCD Basics

Liquid crystal

Liquid crystal refers to the intermediate status of a substance between solid (crystal) and liquid. When crystals with a high level of order in molecular sequence are melted, they generally turn liquid, which has fluidity but no such order at all. However, thin bar-shaped organic molecules, when they are melted, keep their order in a molecular direction although they lose it in molecular positions. In the state in which molecules are in a uniform direction, they also have refractive indices, dielectric constants and other physical characteristics similar to those of crystals, depending on their direction, even though they are liquid. This is why they are called liquid crystal. The diagram below shows the structure of 5CB (4-pentyl-4’-Cyanobiphenyl) as an example of liquid crystal molecules. 

An example of a liquid crystal molecule

Principle of liquid crystal display

A liquid crystal display (LCD) has liquid crystal material sandwiched between two sheets of glass. Without any voltage applied between transparent electrodes, liquid crystal molecules are aligned in parallel with the glass surface. When voltage is applied, they change their direction and they turn vertical to the glass surface. They vary in optical characteristics, depending on their orientation. Therefore, the quantity of light transmission can be controlled by combining the motion of liquid crystal molecules and the direction of polarization of two polarizing plates attached to the both outer sides of the glass sheets. LCDs utilize these characteristics to display images.

Working principle of an LCD

TFT LCD

An LCD consists of many pixels. A pixel consists of three sub-pixels (Red/Green/Blue, RGB). In the case of Full-HD resolution, which is widely used for smartphones, there are more than six million (1,080 x 1,920 x 3 = 6,220,800) sub-pixels. To activate these millions of sub-pixels a TFT is required in each sub-pixel. TFT is an abbreviation for “Thin Film Transistor”. A TFT is a kind of semiconductor device. It serves as a control valve to provide an appropriate voltage onto liquid crystals for individual sub-pixels. A TFT LCD has a liquid crystal layer between a glass substrate formed with TFTs and transparent pixel electrodes and another glass substrate with a color filter (RGB) and transparent counter electrodes. In addition, polarizers are placed on the outer side of each glass substrate and a backlight source on the back side. A change in voltage applied to liquid crystals changes the transmittance of the panel including the two polarizing plates, and thus changes the quantity of light that passes from the backlight to the front surface of the display. This principle allows the TFT LCD to produce full-color images.

Structure of a TFT LCD

Source: https://madhavuniversity.edu.in/liquid-crystalline-materials.html

Source: Merck KGaA

Source: Merck KGaA

After over 120 years of research in liquid crystals, a large number of liquid crystal phases have been discovered. Liquid crystal phases have a range of different structures, but all have one thing in common: they flow in a similar way to viscous liquids, but show the physical behavior of crystals. Their appearance depends on various criteria, including molecular structure and temperature, as well as their concentration and the solvent.

A crystal can be described using a coordinate system. Each atom of a molecule has its specific position. The structure of a crystal can be reduced to a tiny unit, the primitive cell, which is repeated periodically in all three dimensions. This periodicity describes the long-range order of a crystal. A crystal is a highly ordered system in which the physical properties have different characteristics according to the viewing angle. This is called anisotropy. The properties of a liquid crystal phase are also anisotropic, although the structure can no longer be described in a coordinate system. The periodicity and thus the long-range order are lost. Molecules orient themselves by their neighboring molecules, so that only short-range order can be observed. In contrast, a liquid is a completely disordered system, in which the physical properties are isotropic, i.e. directionally independent. What a liquid crystal phase and a liquid have in common is fluidity.

THERMOTROPIC NEMATIC PHASE

In LCD technology, the thermotropic nematic phase is by far the most significant phase. It is formed from rod-shaped (calamitic) molecules that arrange themselves approximately parallel to each other. These molecules can also form smectic phases, which exist in multiple manifestations. Smectic phases are more ordered than nematic phases: as well as the parallel alignment of the molecules, they also form layers.

As the temperature rises, the order of a system decreases. The temperature at which a liquid crystal phase is converted to the isotropic liquid is called the clearing point. A substance may form one or more liquid crystal phases if the structural conditions allow this. However, the appearance of liquid crystal phases is not necessarily a consequence of the molecular structure.

Source: Liquid Crystalline materials used in LCD display

Source: https://madhavuniversity.edu.in/liquid-crystalline-materials.html

Types of LCD Technologies

Source: Merck KGaA

  • Twisted nematic (TN)
  • Vertical alignment (VA)
  • Polymer stabilized VA variant (PS-VA)
  • Self alignment vertical alignment (SA-VA)
  • In-plane switching (IPS)
  • Fringe field switching (FFS)
  • Ultra-brightness fringe field switching (UB-FFS)
  • Blue Phase

Source: Merck KGaA

Components of a LCD Panel

In Plane Switching IPS Technology

  • Unpolarized Light
  • Polarizer
  • Glass Substrate
  • Thin Film Transistor
  • TFT Electrode
  • Orientation Layer
  • Liquid Crystals
  • Polarized Light
  • Orientation Layer
  • Color Filter
  • Glass Substrate
  • Analyzer
  • Emitted Light

Vertical Alignment VA Technology

  • Back Lighting Unit (BLU) – Source of Unpolarized Light
  • 1 st Polarizing Filter – Input Polarizer
  • Glass Substrate – backbone
  • Thin Film Transistor (TFT)
  • TFT Electrode
  • Orientation Layer – Thin Film Transistors
  • RM/additive Polymer layer – orientation of liquid crystal molecules and for fixing “pretilt angle”
  • RM Polymer Layer
  • Liquid Crystals
  • Polarized Light
  • RM/additive polymer layer
  • RM Polymer layer
  • Orientation layer
  • Electrode
  • Color filter
  • Glass Substrate
  • 2 nd Polarizing filter

Materials used in making Displays

Source: Merck KGaA Germany

  • Liquid Crystals
  • OLED Materials
  • Photoresists
  • Siloxanes
  • Silozanes
  • LED Phosphores
  • Quantum Materials
  • Reactive Mesogens

Three main components of a LCD Panel are discussed below in some detail.

  • Backplane Technology
  • Color Filter
  • Backlighting

Backplane Technology

What Is An LTPS LCD?

August 10, 2019

Low-temperature polycrystalline silicon (or LTPS) LCD—also called LTPS TFT LCD—is a new-generation technology product derived from polycrystalline silicon materials. Polycrystalline silicon is synthesised at relatively low temperatures (~650°C and lower) as compared to traditional methods (above 900°C).

Standard LCDs found in many consumer electronics, including cellphones, use amorphous silicon as the liquid for the display unit. Recent technology has replaced this with polycrystalline silicon, which has boosted the screen resolution and response time of devices.

Row/column driver electronics are integrated onto the glass substrate. The number of components in an LTPS LCD module can be reduced by 40 per cent, while the connection part can be reduced by 95 per cent. The LTPS display screen is better in terms of energy consumption and durability, too.

LTPS LCDs are increasingly becoming popular these days. These have a high potential for large-scale production of electronic devices such as flat-panel LCD displays or image sensors.

Amorphous silicon lacks crystal structure, whereas polycrystalline silicon consists of various crystallites or grains, each having an organised lattice (Fig. 1).

Amorphous silicon versus polycrystalline silicon (Credit: Wikipedia)
Fig. 1: Amorphous silicon versus polycrystalline
silicon (Credit: Wikipedia)

Advantages of an LTPS LCD display are:

  • Dynamic and rich colours
  • Fast response and less reflective
  • High picture resolution

Some of its disadvantages are:

  • Deteriorates faster than other LCDs
  • High cost

Display technology explained: A-Si, LTPS, amorphous IGZO, and beyond

ultra slim bezel tablet

LCD or AMOLED1080p vs 2K? There are plenty of contentious topics when it comes to smartphone displays, which all have an impact on the day to day usage of our smartphones. However, one important topic which is often overlooked during analysis and discussion is the type of backplane technology used in the display.

Display makers often throw around terms like A-Si, IGZO, or LTPS. But what do these acronyms actually mean and what’s the impact of backplane technology on user experience? What about future developments?

For clarification, backplane technology describes the materials and assembly designs used for the thin film transistors which drive the main display. In other words, it is the backplane that contains an array of transistors which are responsible for turning the individual pixels on and off, acting therefore as a determining factor when it comes to display resolution, refresh rate, and power consumption.Display Panel TransistorsNote the transistors at the top of each colored pixel.

Examples of backplane technology include amorphous silicon (aSi), low-temperature polycrystalline silicon (LTPS) and indium gallium zinc oxide (IGZO), whilst LCD and OLED are examples of light emitting material types. Some of the different backplane technologies can be used with different display types, so IGZO can be used with either LCD or OLED displays, albeit that some backplanes are more suitable than others.

a-Si

Amorphous silicon has been the go-to material for backplane technology for many years, and comes in a variety of different manufacturing methods, to improve its energy efficiency, refresh speeds, and the display’s viewing angle. Today, a-Si displays make up somewhere between 20 and 25 percent of the smartphone display market.Poly-Si-TFT-vs-a-SiH-TFT-vs-Oxide-TFTA spec comparison of common TFT types.

For mobile phone displays with a pixel density lower than 300 pixels per inch, this technology remains the preferable backplane of choice, mainly due to its low costs and relatively simple manufacturing process. However, when it comes to higher resolution displays and new technologies such as AMOLED, a-Si is beginning to struggle.

AMOLED puts more electrical stress on the transistors compared with LCD, and therefore favours technologies that can offer more current to each pixel. Also, AMOLED pixel transistors take up more space compared with LCDs, blocking more light emissions for AMOLED displays, making a-Si rather unsuitable. As a result, new technologies and manufacturing processes have been developed to meet the increasing demands made of display panels over recent years.

LTPS

LTPS currently sits as the high-bar of backplane manufacturing, and can be spotted behind most of the high end LCD and AMOLED displays found in today’s smartphones.  It is based on a similar technology to a-Si, but a higher process temperature is used to manufacture LTPS, resulting in a material with improved electrical properties.Backplane currentsHigher currents are required for stable OLED panels, which a-Si falls short of.

LTPS is in fact the only technology that really works for AMOLED right now, due to the higher amount of current required by this type of display technology. LTPS also has higher electron mobility, which, as the name suggests, is an indication of how quickly/easily an electron can move through the transistor, with up to 100 times greater mobility than a-Si.

For starters, this allows for much faster switching display panels. The other big benefit of this high mobility is that the transistor size can be shrunk down, whilst still providing the necessary power for most displays. This reduced size can either be put towards energy efficiencies and reduced power consumption, or can be used to squeeze more transistors in side by side, allow for much greater resolution displays. Both of these aspects are becoming increasingly important as smartphones begin to move beyond 1080p, meaning that LTPS is likely to remain a key technology for the foreseeable future.display technology revenue sharesLTPS is by far the most commonly used backplane technology, when you combine its use in LCD and AMOLED panels.

The drawback of LTPS TFT comes from its increasingly complicated manufacturing process and material costs, which makes the technology more expensive to produce, especially as resolutions continue to increase. As an example, a 1080p LCD based on this technology panel costs roughly 14 percent more than a-Si TFT LCD. However, LTPS’s enhanced qualities still mean that it remains the preferred technology for higher resolution displays.

IGZO

Currently, a-Si and LTPS LCD displays make up the largest combined percentage of the smartphone display market. However, IGZO is anticipated as the next technology of choice for mobile displays. Sharp originally began production of its IGZO-TFT LCD panels back in 2012, and has been employing its design in smartphones, tablets and TVs since then. The company has also recent shown off examples of non-rectangular shaped displays based on IGZO. Sharp isn’t the only player in this field — LG and Samsung are both interested in the technology as well.IGZO vs aSi 1Smaller transistors allow for higher pixel densities

The area where IGZO, and other technologies, have often struggled is when it comes to implementations with OLED. ASi has proven rather unsuitable to drive OLED displays, with LTPS providing good performance, but at increasing expense as display size and pixel densities increase. The OLED industry is on the hunt for a technology which combines the low cost and scalability of a-Si with the high performance and stability of LTPS, which is where IGZO comes in.

Why should the industry make the switch over to IGZO? Well, the technology has quite a lot of potential, especially for mobile devices. IGZO’s build materials allow for a decent level of electron mobility, offering 20 to 50 times the electron mobility of amorphous silicon (a-Si), although this isn’t quite as high as LTPS, which leaves you with quite a few design possibilities. IGZO displays can therefore by shrunk down to smaller transistor sizes, resulting in lower power consumption, which provides the added benefit of making the IGZO layer less visible than other types. That means you can run the display at a lower brightness to achieve the same output, reducing power consumption in the process.

IGZO vs aSi 2

One of IGZO’s other benefits is that it is highly scalable, allowing for much higher resolution displays with greatly increased pixel densities. Sharp has already announced plans for panels with 600 pixels per inch. This can be accomplished more easily than with a-Si TFT types due to the smaller transistor size.

Higher electron mobility also lends itself to improved performance when it comes to refresh rate and switching pixels on and off. Sharp has developed a method of pausing pixels, allowing them to maintain their charge for longer periods of time, which again will improve battery life, as well as help create a constantly high quality image.

IGZO vs aSi 3

Smaller IGZO transistors are also touting superior noise isolation compared to a-Si, which should result in a smoother and more sensitive user experience when used with touchscreens. When it comes to IGZO OLED, the technology is well on the way, as Sharp has just unveiled its new 13.3-inch 8K OLED display at SID-2014.

Essentially, IGZO strives to reach the performance benefits of LTPS, whilst keeping fabrications costs as low as possible. LG and Sharp are both working on improving their manufacturing yields this year, with LG aiming for 70% with its new Gen 8 M2 fab. Combined with energy efficient display technologies like OLED, IGZO should be able to offer an excellent balance of cost, energy efficiency, and display quality for mobile devices.

What’s next?

Innovations in display backplanes aren’t stopping with IGZO, as companies are already investing in the next wave, aiming to further improve energy efficiency and display performance. Two examples worth keeping an eye are on are Amorphyx’ amorphous metal nonlinear resistor (AMNR) and CBRITE.lg g3 aa (7 of 22)Higher resolution smartphones, such as the LG G3, are putting increasing demands on the transistor technology behind the scenes.

Starting with AMNR, a spin-off project which came out of Oregon State University, this technology aims to replace the common thin-film transistors with a simplified two-terminal current tunnelling device, which essentially acts as a “dimmer switch”.

This developing technology can be manufacturing on a process that leverages a-Si TFT production equipment, which should keep costs down when it comes to switching production, whilst also offering a 40 percent lower cost of production compared with a-Si. AMNR is also touting better optical performance than a-Si and a complete lack of sensitivity to light, unlike IGZO. AMNR could end up offering a new cost effective option for mobile displays, while making improvements in power consumption too.

CBRITE, on the other hand, is working on its own metal oxide TFT, which has a material and process that delivers greater carrier mobility than IGZO. Electron mobility can happily reach 30cm²/V·sec, around the speed of IGZO, and has been demonstrated reaching 80cm²/V·sec, which is almost as high as LTPS. CBRITE also appears to lend itself nicely to the higher resolution and lower power consumption requirements of future mobile display technologies.LTPS vs CBRITE performance with OLEDLTPS vs CBRITE spec comparison for use with OLED displays

Furthermore, this technology is manufactured from a five-mask process, which reduces costs even compared to a-Si and will certainly make it much cheaper to manufacture than the 9 to 12 mask LTSP process. CBITE is expected to start shipping products sometime in 2015 or 2016, although whether this will end up in mobile devices so soon is currently unknown.

Smartphones are already benefiting from improvements in screen technology, and some would argue that things are already as good as they need to be, but the display industry still has plenty to show us over the next few years.

Color Filter Array (CFA)

Source: BASF

Source: BASF

Cathode ray tube television sets have long had their day. Flat screen TVs now provide energy-efficient, low-emission entertainment in three out of four German households, according to the Federal Statistical Office. And this figure is rising, Germans are estimated to have purchased eight million flat screen television sets in 2015, most of which are LCDs. LCD technology is also the basis for many other contemporary communication devices, including smartphones, laptops and tablets. After all, with experts forecasting six percent global annual sales growth for flat-panel displays until 2020.

LCD stands for liquid crystal display. Liquid crystals form the basis for billions of flat-panel displays. The American, George H. Heilmeier, unveiled the first monochrome LCD monitor to the expert community in 1968. Commercialization of the first color monitors took another 20 years. Flat screen TVs started sweeping the world in the 1990s, mainly because of the availability of high-performance color filter materials.

The images on a liquid crystal display with the standard resolution are made up of about two million picture elements, better known as pixels. The color filter pigments attached to the liquid crystal cells are what give each pixel its color. Screen contrast and color purity remain a challenge, however. 

Pigment properties make all the difference

Red, green, and blue: Every pixel contains these three primary colors. The colors are composed of tiny crystals about a thousand times smaller in diameter than a human hair. The crystals act as a filter for the white backlight and only allow light waves from a selected range of the visible spectrum to pass through. These light waves show one of the three colors in its purest possible form. The filters block all the other wavelengths. “A good pigment has a significant impact on the brilliance of the colors the viewer sees,” said Dr. Hans Reichert, head of colorants research at BASF.

“Although perfect color selection is not feasible with absorbing materials, we come fairly close to perfection with our red filters.” Color purity also has an impact on the range of colors available. The greater the purity of the three primary colors, the more permutations that can be achieved by mixing them – and the more colorful the image.

The picture shows a chemical reaction in the lab yielding diketopyrrolopyrroles, the substances BASF’s red filter pigments are made of. Diketopyrrolopyrroles are aromatic organic ring compounds mainly consisting of carbon, nitrogen and oxygen.

The basic principle is simple. When the color red appears on the screen, the corresponding subpixel lets the red portion of light pass through and absorbs the rest. The other two subpixels – for blue and green – are deactivated when this happens. If, on the other hand, light penetrates through the red and green subpixel while the blue is deactivated, the colors combine to give a rich yellow. Fine-tuning the portions of the three primary colors in this manner produces millions of hues.

The liquid crystals fine-tune the blend of colors by twisting the plane of oscillation of the light waves. “This determines the brightness and color of the subpixels,” said Ger de Keyzer, in charge of applications engineering for color filter materials at BASF. “The liquid crystals change direction, and in that way alter their optical properties depending on the voltage applied.” They rotate the plane of oscillation of light waves to allow the light to pass through the second polarization filter. When an electrical field is applied, however, the crystals prevent some or all of the light from getting through.

To ensure that subpixels switch on and off the way they are supposed to, it is essential to prevent interferences from the color filter pigments. Any interferences resulting in scattering and depolarization of light will allow the light to pass uncontrolled through the filter. This contaminates the colors and compromises the contrast.

Smaller the better

“A good rule of thumb is: The smaller and more regular the crystals, the lower the scattering and the better the LCD image quality,” de Keyzer said. Researchers control the process mainly by managing the conditions in which pigment crystallization takes place. The underlying molecular structure is what determines which parts of the color spectrum are filtered out.

The organic red pigments that BASF manufactures consist mainly of carbon, nitrogen, and oxygen, and belong to the class of diketopyrrolopyrroles (DPPs). Blue and green pigments are phthalocyanine metal complex compounds. The raw product produced through chemical synthesis is mainly composed of irregular particles. They must then be brought into the ideal size and shape. This is done by a process called pigment finishing. Crystals that are too small are dissolved and precipitated onto the larger crystals. Crystals that are too large are broken into smaller pieces by a mechanical process until the balance is right. Dr. Roman Lenz, BASF lab team leader in charge of new color filter material synthesis, explained: “Our technology gives us color particles of 20 to 40 nanometers – small enough to reduce light scattering to an absolute minimum but large enough to provide a high degree of stability.” BASF has honed the technology almost to perfection with its products. The color particles in the latest generation of the Irgaphor® Red product suite are smaller than 0.00004 millimeters, and have double the contrast performance of their predecessors.

Tomorrow’s television screens will have to meet even higher expectations in terms of resolution and color purity. In anticipation of the new demands, Lenz and his colleagues are taking their lab experiments one step further. Their aim is to find new materials that will show colors in an even more natural light.

Source: STRUCTURE OF COLOR FILTERS/Toppan

Market Demands for Color Filters

Source: Toppan Japan

Source: STRUCTURE OF COLOR FILTERS/Toppan

Manufacturing Process of Color Filters

Source: Toppan Japan

Dyes and Pigments Used in Color Filters

  • Red Pigment/Dye
  • Green Pigment/Dye
  • Blue Pigment/Dye

High Transmittance, Low Scattering

Source: Past, present, and future of WCG technology in display

Dyes/Pigment Suppliers

  • DIC/Sun Chemicals. – Green and Blue
  • BASF – Red
  • Merck KGaA
  • Solvay
  • Clariant
  • Sumitomo Chemicals

Source: DIC Japan

Pigments for Color Filters Used in LCDs and OLED Displays(Functional Pigments)

Pigments for Color Filters Used in LCDs and OLED Displays(Functional Pigments)

Value Creation Global market-leading pigments that deliver outstanding brightness and picture quality

Color images on liquid crystal displays (LCDs) used in LCD televisions, computers and smartphones are produced using the three primary colors of light—red (R), green (G) and blue (B). These colors are created using pigments. LCDs produce images by transmitting light emitted from a backlight lamp through a color filter to which an RGB pattern has been applied. As a consequence, the pigments used in the color filter are crucial to picture quality.
With Japan’s shift to digital terrestrial television driving up demand for flatpanel LCD televisions and the popularity of smartphones increasing, in 2007 DIC launched the G58 series of green pigments, which achieved a remarkable increase in brightness. The series includes FASTOGEN GREEN A350, a green pigment characterized by outstanding brightness and contrast that ensures excellent picture quality even with little light from the backlight. In fiscal year 2014, DIC developed the G59 series of green pigments for wide color gamut color filters, which deliver superior brightness and color reproduction, making them suitable for use in filters for next-generation high-definition displays, including those for ultra-high-definition (UHD) televisions. DIC currently enjoys an 85%- plus share of the global market for green pigments for color filters, making its products the de facto standard. DIC also manufactures blue pigments for color filters. In 2012, the Company developed the A series, which boasts a superb balance between brightness and contrast. The optical properties of pigments in this series have earned high marks from smartphone manufacturers and boosted DIC’s share of the global market for blue pigments to approximately 50%.
DIC’s pigments for color filters, which satisfy the diverse performance requirements of displays used in LCD televisions, smartphones, tablets and notebook computers while at the same time adding value, have been adopted for use by many color filter manufacturers. In addition to improving picture quality, these pigments reduce energy consumption and, by extension, lower emissions of CO2. Having positioned pigments for color filters as a business that it expects to drive growth, DIC continues working to reinforce its development and product supply capabilities.

Applying technologies amassed through the production of printing inks to the development and expansion of functional pigments that have become the de facto standard worldwide

DIC first succeeded in developing offset printing inks in-house in 1915 and 10 years later began production of organic pigments for its own use. Over subsequent years, the Company amassed development and design capabilities, as well as production technologies, crucial to the manufacture of fine chemicals and in 1973 commercialized revolutionary high-performance, long-lasting nematic LCs, which were adopted by Sharp Corporation for use in the world’s first pocket calculator incorporating an LCD. DIC’s passion and development prowess are also evident in its pigments for color filters.
Large-screen LCD televisions are expected to deliver superbly realistic and accurate color reproduction. The small LCDs used in smartphones and other devices must be clear, easy to read and bright enough to ensure legibility even with less light. This is because reduced light requirements results in longer battery life. Increasing brightness requires making color filters thinner and more transparent, but this alone will not deliver vivid colors and resolution. With the question of how best to realize both high brightness and vivid colors on ongoing challenge for display manufacturers, DIC has responded by developing innovative pigments for this application.
Copper has traditionally been the central material used in green pigments. In developing its green pigments for color filters, DIC defied conventional wisdom by exploring the use of a different central material with the goal of further enhancing performance characteristics. Through a process of trial and error, the Company narrowed down the list of suitable materials from a wide range of candidates, eventually choosing zinc. DIC also significantly improved transparency by reducing the size of pigment particles, thereby achieving a dramatic increase in contrast, which ensures a bright, clear picture quality even with less light. The outcome of these efforts was the groundbreaking G58 series.

Picture quality is influenced significantly by the brightness and contrast of the pigment used in the color filter. (Left: High brightness and high contrast; Right: Low brightness and low contrast)

In the area of blue pigments for color filters, DIC also leveraged its superior molecular design capabilities to achieve outstanding tinting strength and precise particle size control. To develop the A series of blue pigments for color filters, the Company also employed specialty particle surface processing to ensure highly stable dispersion, realizing an excellent balance between brightness and contrast. Products in the A series currently dominate the market for blue pigments for color filters, delivering excellent optical properties that continue to earn solid marks from smartphone manufacturers.
DIC’s success in developing a steady stream of pioneering functional pigments is supported by the seamless integration of basic technologies amassed in various fields as a manufacturer of color materials, the crossbusiness R&D configuration of its Central Research Laboratories and production technologies that facilitate the mass production of products with performance characteristics realized in the laboratory.

KEY PERSON of DIC

We are making full use of the DIC Group’s global network at all stages, from the promotion of product strategies through to the expansion of sales channels.

Manager, Pigments Sales Department 2, Pigments Product Division Naoto Akiyama

The value chain extending from functional pigments through to color filters for LCDs encompasses manufacturers of pigments, pigment dispersions, resist inks, color filters and LCDs. In developing pigments for color filters, we gather information on the latest trends from LCD manufacturers, which we apply to the formulation of nextgeneration product strategies.
Production of pigment dispersions, color filters and LCDs is concentrated primarily in East Asia. Recent years have seen a particularly sharp increase in the People’s Republic of China (PRC), which is on the verge of overtaking the Republic of Korea (ROK) as No. 1 in terms of volume produced. We are making full use of the DIC Group’s global network by working closely with local Group companies to bolster the adoption of DIC pigments for color filters for use in LCDs.

Manager, Pigments Sales Department 2, Pigments Product Division Naoto Akiyama

Source: Emperor Chemicals China

Color filter (CF, COLOR FILTER) is one of the most important components of a color liquid crystal display, which directly determines the quality of the color image of the display. The rapid growth of LCD displays is supported by the strong demand for flat-panel color displays from notebooks (PCs, Personal Computers). The portable characteristics of the LCD, such as small outline size, thinness, lightness, high definition, and low power consumption, greatly meet the needs of notebook PCs. It is believed that in the multimedia age, TFT-LCD will have a huge advantage. Color filters are the key elements that make up a color image.

The color of the color filter may be dyed with a water-soluble dye, or a pigment dispersion method in which a pigment is colored. The pigment dispersion method includes the use of UV-curable phtoresists: colored pigments, UV-curable carrier resins, photo initiators, organic solvents, dispersants and other ingredients, among which organic pigments are colored The requirements for coloring properties of the agent, such as high vividness, specific primary color (RGB), three spectral hue, durability, chemical resistance and high transparency, etc., are mainly the selection of high-grade organic pigments through efficient dispersion Treatment process to obtain a pigment dispersion with a fine and stable particle size, and to prepare photoresist inks for color filters. Compared with the dyeing method, it has excellent moisture resistance, light fastness, and heat stability, but the pigment dispersion must be further improved Technology to prepare color filters with high transparency and pigment purity.

The color filter in the liquid crystal display adopts the principle of additive method, and uses blue, green and red organic pigments. Based on the spectral color and durability requirements of colorants, pigments for blue and green color photoresist inks are usually selected: phthalocyanine CI pigment blue 15: 1, pigment blue 15 :0, pigment blue 15: 3, Pigment Blue 15: 4, Pigment Blue 15: 6, and anthraquinone-based pigments such as CI Pigment Blue 60 and the like. Green tone C.I. Pigment Green 36.

In particular, the spectral absorption characteristics of CI Pigment Blue 15: 6 and CI Pigment Green 36 are well matched with the wavelengths and emission intensities of the blue, green, and red fluorescence emission spectra (fluorescence lamp for LCD backlight) in liquid crystal displays. In order to further improve the spectral characteristics, it is possible to adjust by adding a small amount of pigments of other colors, such as adding CI Pigment Violet 23 to obtain a stronger red light blue, and adding CI Pigment Yellow 150 to obtain a stronger yellow light green.

The selection of pigments should be based on obtaining a high-definition spectrum, eliminating unnecessary wavelength spectra, and retaining only the necessary color light. Selecting the organic pigment varieties required by the appendix, the color light purity and transmittance of the color filter can also be improved.

In order to adjust the spectral characteristics of the color filter, such as hue, tinting strength and contrast, for red, green and blue spectrum pigments, a second pigment component is often added to fight the color. For example, select some yellow with excellent durability, Purple organic pigment varieties, CI Pigment Yellow 138, CI Pigment Yellow 139, CI Pigment Yellow 150, CI Pigment Yellow 180, CI Pigment Purple 23 and other varieties.

Recommended organic pigments of three primary colors of red, blue and green are as follows:

Red organic pigments: The main varieties are high-grade organic pigments such as: C.I. Pigment Red 122, C.I. Pigment Red 177, C.I. Pigment Red 242, C.I. Pigment Red 254, and specific yellow organic pigment varieties are added if necessary.

Green organic pigments: C.I. Pigment Green 7, C.I. Pigment Green 36 is mainly selected, and specific yellow organic pigment varieties are matched, and specific yellow organic pigment varieties are added if necessary.

Blue organic pigments: C.I.Pigment Blue 5, C.I.Pigment Blue 15: 3, C.I.Pigment Blue 15: 6, C.I.Pigment Blue 60, etc., if necessary, specific yellow pigments and pigment violet 23.

Color Filter Less Technology

The liquid crystal display (LCD)is a thin, flat display device, which is made up of many number of color or monochrome pixels arrayed in front of a light source or reflector. It is prized for its superb image quality, such as low-voltage power source, low manufacturing cost, compared with other display device including CRT, plasma, projection, etc. Today the LCD device has been widely used in portable electronics such as cell phones, personal computers, medium and also in large size television display.

The LCD device consists of two major components, TFT-LCD panel and Back Light Unit (BLU). As LCD device can not light actively itself, thus a form of illumination, back light unit is needed for its display. While one of the key parts in LCD panel is color filter. The color filter is a film frame consists of RGB primary colors, and its function is to generate three basic colors from the back light source for LCD display. As a whole, back light and color filter are the two vital components of the perfect color display for LCD device.

Traditionally people use the cold cathode fluorescent lamp (CCFL)as the back light source for medium and large size LCD device. However CCFL has several disadvantages. For example, narrow color representation, low efficiency, complex structure, limited life, and the CCFL needs to be driven by a high-voltage inverter, consequently requires more space. Another disadvantage is the environmental problem for the mercury inside it. So people try to find an ideal back light module for LCD display.

Nowadays, the back light technology for LCD device towards the trend of using light emitting devices (LED). For its excellent advantages, the LCD device based on LED back light owns promoted display performance. As a new generation of solid-state light source, LED can produce very narrow spectrum, thus can generate a high color saturation, as a result it provides LCD device delivering a wider color gamut of above 100% of NTSC specification than the only 70% of CCFL back light. Moreover the LED only need DC power drive instead of a DC-AC inverter, so simplifies the back light structure. In a word, LED back light makes LCD obtain quite a higher display quality than the conventional CCFL back light. Despite of these advantages, there are also several challenges for LED back light technology currently, such as efficiency, stable ability, heat dissipation and cost etc. so people are trying to get some substantial breakthrough at the technical problems above to make LED back light as the key technology part for LCD device.

Color filter is another key component of the LCD device. As a sophisticated part, its fabrication takes an extremely complicated process, consequently the color filter occupies quite a large proportion of the production cost of the LCD devices. While a serious deficiency is its greatly influence on the light utilization rate. Generally speaking, only about 30% the amount of the light emitted from the back light can be delivered, while the rest of the light is wasted while passing the color filter.

For this, people prefer to designing a new form of LCD module which can get rid of the color filter, to promote the efficiency of light utilization. So an idea of Color Filter-Less (CFL) technology was put forward. The Field Sequential color LCD designed by Sumsang company is the first form of Color Filter-Less technology which is an idea of changing the space color mixing into the time color mixing.

Especially, we design a film frame which is patterned of red and green emitting phosphors, then make it be excited by blue light from a blue LED panel we fabricated. For its special emitting mechanism, this phosphor film can generate red and green emissions respectively. Meanwhile not all the blue light is absorbed by the phosphors, the remnant blue light can pass the film frame, therefore we can achieve a panel frame on which the RGB colors mixed together, thus to replace of the color filter in LCD device.

Backlighting

  • CCFL Cold Cathode Fluorescent Lamp
  • LED
    • RGB LED Backlighting
    • An Edge backlight with white LEDs
    • A flat backlight based on white LEDs

Source: TFTCentral.co.UK

Recent Technological Innovations

  • LCD with LED Backlighting
  • Mini LED
  • Micro LED
  • LCD with Quantum Dot QDEF
  • Wide Color Gamut WCG
  • Color Filter Less LCD
  • Vertically Stacked OLED Layers (SOLED)
  • Quantum Dot Color Filter QDCF
  • RGBW LED 4 colors
  • Bright Dyes and Pigments
  • Color Filters using Structural Colors
  • Transreflective Displays
  • Reflective Displays
  • Blue LED plus Red Green Color Filter
  • Flexible displays -bendable, rollable, fixed, curved, foldable
  • Touch Screens
  • Transparent Displays

Vertically Stacked RGB OLED layers (SOLED)

Source: Three-terminal RGB full-color OLED pixels for ultrahigh density displays

https://www.nature.com/articles/s41598-018-27976-z

TFT based Vertically stacked OLEDs

Source: Thin-film transistor-driven vertically stacked full-color organic light-emitting diodes for high-resolution active-matrix displays

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7264127/

Supply Chain for TFT-LCD Manufacturing

Light Emitting Diodes (LEDs)

Source: https://www.lighting.philips.com/main/support/support/faqs/white-light-and-colour/what-are-the-different-types-of-rgb-leds

What are the different types of RGB LEDs?

The following are the different types of RGB LEDs:

  • R/G/B/W – Has an additional white LED. This is often used where you need a pure white as well other combined colors.
  • RGB / 3 in 1 LED – Uses a red, a blue and a green LED chip are mounted within a common light engine and focused through a lens to produce a more uniform hue across the beam of light.
  • RGBW / 4 in 1 LED – similar to the RGB LED but with a warm white LED integrated in the light engine to offer more color tones.
  • RGBA – Has an additional amber LED chip.

White vs RGB LEDs

White LED’s are actually blue leds with a yellow phosphor, and thus creating an white impression. This technique allows a colour gamut slightly wider than sRGB, but not very “colourfull”. RGB leds consist of 3 individual colour leds, red, green and blue. These allow an enourmous colour gamut that covers most standards like AdobeRGB and NTSC. Panels with RGB LED’s are much more expensive, as they need much more calibration logic. It is very hard to tame extreme gamut for say sRGB use, and the ballance of the colours is constantly monitored. RGB LED displays are doing twice the price of WLED’s with ease.

Composition of OLED Display

  • RGB OLED
  • White OLED

Source: Past, present, and future of WCG technology in display

OLED Technologies

  • Shadow Mask Patterning Method
  • Color Filter Method

Source: https://global.pioneer/en/corp/group/tohokupioneer/mainbusinesses/oled/introduction/

Color Patterning Technologies

Ink Jet and Photolithography are methods of making color filters.

Source: https://onlinelibrary.wiley.com/doi/10.1002/9781119187493.ch5

This chapter discusses the color patterning technologies, which gives major contribution to cost and productivity. The technologies discussed include shadow mask patterning, white‐color filter method, laser‐induced thermal imaging method, radiation‐induced sublimation transfer method, and dual‐plate OLED display method. Low material utilization can bring high cost, so it is very critical to suppress material consumption during OLED display manufacturing. To address this, various high‐material‐utilization next‐generation OLED manufacturing processes, such as the vapor injection source technology (VIST) method, hot‐wall method, and organic vapor‐phase deposition (OVPD) have been proposed and are discussed in the chapter.

Source: https://www.findlight.net/blog/2020/01/22/oled-production-composition-and-color-patterning-techniques/

OLED Production: Composition and Color Patterning Techniques

Last updated on January 22, 2020

Organic Light-Emitting Diodes (OLEDs) are most famously known for their use in foldable smart phone displays. From the Samsung Galaxy Fold to the Huawei Mate X (2019), these devices offer huge screens that can fold down to the size of a more traditional smartphone screen. This revolutionary new technology is made possible by the properties and composition of OLED screens. In traditional Liquid Crystal Display (LCD) screens, a glass pane covers the actual liquid crystal display that emits the light. On the other hand, OLED screens have the light emitting technology already built into them. Thus, when you touch interact with an OLED device, you are touching the actual display too. OLED screens are often made of a type of plastic, which allows for flexibility and folding screens. These devices also require OLED color patterning techniques in order to integrate color into the display devices, which we will describe further in the upcoming sections.

Intro to OLED Composition

Now, we will brief on the composition and integration of OLED technology in this plastic screen. OLEDs are made of two or three organic layers sandwiched between two electrodes (cathode and anode) on top of a substrate layer. The organic layers and electrodes emit light in response to an electric current. One of the most difficult processes in manufacturing these OLEDs is attaching the organic layers to the substrate. For example, organic vapor phase deposition and inkjet printing are both efficient methods that can reduce the cost of producing OLED displays.OLED cell structure diagram

OLED components include organic layers that are made of organic molecules or polymers. This diagram is a two (organic) layer model.
Courtesy of HowStuffWorks.

Another big part of OLED manufacturing is the color patterning step, which allows the OLED device to display color. There are various methods in use for OLED color patterning, including photolithography. Lithography is commonly used for semiconductors and TFTs, but presents challenges for OLEDs. This is due to the high temperature and humid conditions required for attaching OLED layers together. In this article we will explore three different color patterning technologies that have arisen for more efficient and accurate OLED optical manufacturing.

OLED Color Patterning and Masking Techniques

First, we have the “Shadow Mask Patterning Method” consists of placing red, green, and blue light emitting layers in a pattern in each pixel of the OLED device. Further, this has the advantage that each subpixel gets appointed a single, distinct color which produces great clarity of images. Unlike the other methods, there are no outer color filters required to produce the images. Thus, this method saves energy and is one of the most efficient. However, utilizing shadow masks can be an error filled process because the RBG subpixel pattern is outlined with a physical mask a.k.a stencil. We show an example of an accuracy error and its effects in the images below.Shadow RBG mask error

Error produced in processing an OLED with a red pixel mask. We can see that the spacing in the pattern is off around the red arrow. Courtesy of Tsujimura.OLED screen color variation

The resulting color variation in OLED screen due to shadow mask deformation. shown above. Courtesy of Tsujimura.

Second, we have the “Color Filter Method” a.k.a. “White+Color Filter Patterning” method. In this method, the OLED itself is also designed and manufactured with all three color elements in each pixel. However, different from the “Shadow Mask Patterning” method, these OLEDs only produce white light. Next, additional red, green, and blue color filters are utilized to match the desired color output. Accordingly, this process allows for a dynamic range of colors to be emitted with different levels of filtering. However, a big consequence of using color filters is that the purity of the image may be compromised due to interactions of the OLED light and physical color filters. Equally important is the high power consumption this method eats up. Because the color filters absorb most of the light intensity, the process requires a constant, powerful back light.OLED white + color filter method

Schematic diagram of White+Color filter patterning method for OLEDs. Courtesy of Tsujimura.

Rising OLED Color Patterning Techniques: Electron Beams

In 2016, a new approach for OLED color patterning was developed at the Fraunhofer Institute for Organic Electronics. Researchers utilized electron beam technology to color pattern the organic layers in the OLED. Because this process acted on the micro-scale, it produced extremely accurate, high-resolution results, even with the help of color filters. Further, it also allowed for complex patterns and high-definition (HD) grayscale images. Since then, this technology has been developed and advanced to that of full-color working OLED displays, without the use of external filters.

Now, we will discuss an overview about how the electron beam process works. First, an OLED is produced containing all three RGB organic emitting layers. Akin to the previously mentioned processes, this OLED is designed to produce only white light. Next, a thermal electron beam is directed on the white emitting OLED. The electron beam excites certain molecules in the organic layer of the OLED, which causes the molecules or atoms to separate and become structured. Consequently, the thickness of different areas in the OLED organic layer changes and pixels with distinct colors (RGB) are formed. Moreover, the electron beam patterning process allows for microstructuring into color pixels without perturbing the other substrate and electrode layers.OLED color patterning probe station

Probe station with patterned OLEDs in the clean room.
Courtesy of Fraunhofer FEP.

Conclusion

As more AMOLED, and flexible displays enter the market, OLED technology will continue to become more popular and widespread. One of the most important considerations for OLED availability in mass market, is in screen color production. Rising techniques such as the Electron Beam Patterning method can produce high quality, low cost, and energy efficiency. Another key consideration in OLED screen production is low material consumption. Further rising techniques in research that allow for low material costs include the vapor injection source technology (VIST) method, hot‐wall method, and organic vapor‐phase deposition (OVPD) [1].

This article is made possible by Gentec-EO, the market leader in the manufacture of light detection devices.

Further Reading

[1] https://onlinelibrary.wiley.com/doi/10.1002/9781119187493.ch5

Supply Chains of OLED Displays

Cover Glass

  • Corning Glass
  • Samsung Corning Advanced Glass

TFT Backplane

  • Samsung UBE Materials
  • Sumitomo Chemicals

Frontplane

  • Universal Display Corporation UDC USA

Encapsulation

  • Samsung SDI for Flex OLED
  • KYORITSU CHEMICAL Japan

IC Driver

  • Samsung Semiconductors
  • Synaptics USA

Global Supply Chains for OLED Displays

Silica Sand

  1. Sibelico (Belgium)
  2. US Silica (US)
  3. Emerge Energy (US)
  4. Badger Mining (US)
  5. Wuxi Quechen Silicon Chemical Co. (China)

Display Glass

  1. Corning (US)
  2. Asahi Glass (Japan)
  3. Nippon Electric Glass (Japan)

IC Driver

  1. Samsung (South Korea)
  2. Novatek (Taiwan)
  3. Himax (Taiwan)
  4. Silicon Works (South Korea)
  5. Synaptics (US)

OLED Materials

  1. UDC (US)
  2. Dow DuPont (US)
  3. Merck (US)
  4. Idemitsu Kosan (Japan)
  5. LG Chem (South Korea)

QLED, QDLED, QDOLED, Mini-LED, Micro-LED: What is in the name?

Source: https://www.displayninja.com/mini-led-vs-microled/

Micro LED and Mini LED

MicroLED is the next generation of display technology. Just like OLED, it produces its own light and therefore is capable of infinite contrast ratio. However, since it doesn’t use organic materials, it won’t deteriorate or burn-in over time.

What’s more, MicroLED displays will be brighter than OLED displays, and you will be able to customize their size, aspect ratio, and resolution (modular displays).

Mini-LED, on the other hand, improves on the existing LCDs by replacing their LED backlights with mini-LED backlights, which consist of more efficient and numerous light-emitting diodes that will increase contrast ratio, uniformity, response time, etc.

Although similar in name, microLED and mini-LED technologies are fundamentally diverse.

What is MicroLED?

MicroLED is the leading-edge display technology that is yet to be adjusted to the consumer market; in simpler terms, it’s the display technology of the not-so-distant future.

Similarly to OLED (Organic Light Emitting Diode) technology, MicroLED doesn’t rely on a backlight to produce light. Instead, it uses self-emissive microscopic LEDs, which allow for infinite contrast ratio, just like on OLED displays.

However, unlike OLED, MicroLED technology has no organic materials, so it won’t degrade over time, and you won’t have to worry about image burn-in.

Further, MicroLED displays are capable of higher luminance emission in comparison to OLEDs, which will allow for better details in highlights of the picture for a superior HDR (High Dynamic Range) viewing experience.

Lastly, they can have a unique modular characteristic that would allow you to customize the display’s screen size, resolution, and aspect ratio to your liking by arranging and connecting more panels together.Shop Related Products

What is Mini-LED?

Mini-LED technology improves on the existing LCDs.

It replaces their LED backlights with Mini-LED backlights, which consist of more LEDs that can offer a higher contrast ratio, better uniformity, faster response times, etc.

Mini-LED displays will be cheaper than OLEDs, but not better than them. So, Mini-LED is sort of a display technology in-between the standard LED-backlight LCDs and OLED displays.

The ASUS PG27UQX will feature 2,304 mini LEDs divided into 576 zones (4 LEDs per zone), whereas the original model has 384 zones for local dimming in comparison.

This will significantly alleviate one of the main issues of the PG27UQ, which is image bloom/halo.

When one zone is fully illuminated, but the zones surrounding it are dim, a certain amount of light will bleed from the lit zone to the dim zones, which generates the halo/bloom effect.

Since the PG27UQX has more zones, this issue will be decreased by ~33%. At the same time, the monitor will consume 7% less power and be (relatively) only slightly pricier than the PG27UQ model.

Source: https://www.radiantvisionsystems.com/blog/display-landscape-mini-and-microleds?gclid=EAIaIQobChMItvP3pdvR7gIVqf_ICh1jxwFJEAMYASAAEgL5PPD_BwE

The Display Landscape of Mini- and Micro-LEDs

First there was LED (light emitting diode) display technology, commercialized in 1994. OLED (organic LED) products came on the market in 1997. Then microLEDs began to emerge in 2010. And now we’ve been hearing about a new display technology category: miniLEDs, poised to enter the market in 2019.1

As the name would imply, a miniLED is small—but not as small as a microLED (µLED). While there are no official definitions, microLEDs are typically less than 50 micrometers (µm) square, with most falling in the 3–15 µm size range. Generally, the term miniLED (sometimes also called “sub-millimeter light emitting diodes”) refers to LEDs that are roughly 100 µm square (0.1 mm square), although “mini” can also simply describe any LED between micro and traditional size.

LED landscape as of 2018. Image Source: “MiniLED for Display Applications: LCD and Digital Signage” report by Yole Développement, October 2018.

Though they share many similarities, miniLEDs and microLEDs are also different in some key ways. MicroLEDs are not just shrunken versions of their miniLED sisters. The two LED types have different performance and structures. LEDinside characterized the difference as follows: “Micro LED is a new-generation display technology, a miniaturized LED with matrix. In simple terms, the LED backlight is thinner, miniaturized, and arrayed, with the LED unit smaller than 100 micrometers. Each pixel is individually addressed and driven to emit light (self-emitting), just like OLED…Mini LED is a transitional technology between traditional LED and Micro LED, and is an improved version of traditional LED backlight.”2

Additionally, a driving factor in the recent emergence of miniLEDs is that they are less expensive to produce, largely because current fabrication facilities can more quickly be switched over to miniLED production. MiniLEDs are essentially a variation of already mature LED technology.

MicroLED Fabrication Challenges

MicroLEDs are typically made from Gallium-nitride-based LED materials, which create brighter displays (many times brighter than OLED) with much greater efficiency than traditional LEDs. This makes them attractive for applications that need both brightness and efficiency such as smart watches, and particularly for head-up displays (HUDs) and augmented reality systems that are likely to be viewed against ambient light backgrounds

OLED screen manufacturing has been somewhat costly to date, limiting its adoption primarily to smaller screen sizes like smart phones. Likewise, producing an entire television screen out of microLED chips has so far proven to be challenging. MicroLEDs require new assembly technologies, die structure, and manufacturing infrastructure. For commercialization, fabricators must find methods that yield high quality with microscopic accuracy while also achieving mass-production speeds. For starters, a miniLED backlight screen may be made up of thousands of individual miniLED units; a microLED screen is composed of millions of tiny LEDs.

To fabricate a display, each individual microLED must be transferred to a backplane that holds the array of units in place. The transfer equipment used to place microLED units is required to have a high degree of precision, with placement accurate to within +/- 1.5 µm. Existing pick & place LED assembly equipment can only achieve +/- 34 µm accuracy (multi-chip per transfer). Flip chip bonders typically feature accuracy of +/-1.5 µm—but only for a single unit at a time. Both of these traditional LED transfer methods are not accurate enough for mass production of microLEDs. 

New transfer solutions are under development, including fluid assembly, laser transfer, and roller transfer. Researchers are also working to resolve the challenges associated with integrating compound semiconductor microLEDs with silicon-based integrated circuit devices that have very different material properties and fabrication processes. Traditional chip bonding and wafer bonding processes don’t provide efficient mass transfer for microLED, so various thin-film-transfer technologies are being explored.

Despite Samsung’s introduction of a prototype 75-inch microLED television at the recent CES show (below), microLED products are not expected to reach the general market until 2021.3

Han Jong-hee, president of Samsung Electronics’s video display business, introduces a new 75-inch microLED TV in Las Vegas on January 6, 2019. Photo Source: Business Korea

MiniLED Advantages

By contrast, miniLED chips do not present similar production complications. Because they are just smaller versions of traditional LEDs, they can be manufactured in existing fabrication facilities with minimal reconfiguration. This ease means miniLED production is already underway and devices will reach the market this year for applications in gaming displays and signage, followed by backlight products such as smartphones, TVs, virtual reality devices, and automotive displays.

For example, miniLEDs can be used to upgrade existing LCD displays with “ultra-thin, multi-zone local dimming backlight units (BLU) that enable form factors and contrast performance”4 that rival the quality of OLED displays. MiniLEDs also have an advantage as a cost-effective solution for narrow-pixel-pitch LED direct-view displays such as indoor and outdoor digital signage applications.

MiniLED backlight television from Chinese manufacturer TLC displayed at CES 2019. Photo Source: FlatpanelsHD.

 MicroLEDs do offer high luminous efficiency, brightness, contrast, reliability and a short response time, but they are likely to be priced at more than three times traditional LED screens during initial the initial stages of mass production. MiniLEDs, while they perform more like traditional LEDs, do have advantages when it comes to HDR and notched or curved display designs, and could launch at just 20% above standard LCD panel prices.5 According to PCWorld, “at this stage, the biggest difference between microLED and miniLED for consumers is that microLED is likely to make it to market as a fully-fledged next-generation display technology of its own while miniLED is likely to mostly be used by manufacturers to enhance existing display technologies.”6

Together, microLEDs and miniLEDs are expected to have roughly equal shares of a $1.3 billion market by 2022.7

Quality Assurance for All LED Types

Whether LED or OLED, micro- or mini-, LED display products of all types are jostling for room in a highly competitive marketplace, where customers expect a perfect viewing experience right out of the box. Defects, variations in color or brightness, and other irregularities can quickly deflate buyer satisfaction,  hurt brand reputation, and erode market share.

To ensure the absolute quality of OLED- and LED-based devices, Radiant’s ProMetric® Imaging Photometers and Colorimeters measure display performance and uniformity down to the pixel and subpixel level, matching the acuity and discernment of human visual perception.

CITATIONS:

  1. YiningChen, “Mini LED Applications to be Launched in 2019 and Micro LED Displays in 2021.” LEDinside, October 19, 2018.  LINK
  2. Evangeline H, “Difference between Micro LED and Mini LED.” LEDinside,May 8, 2018. LINK
  3. YiningChen, “Mini LED Applications to be Launched in 2019 and Micro LED Displays in 2021.” LEDinside, October 19, 2018.  LINK
  4. “MiniLED for Display Applications: LCD and Digital Signage” report by Yole Développement, October 2018, as reported in “Mini-LED adoption driven by high-end LCD displays and narrow-pixel-pitch LED direct-view digital signage”. Semiconductor Today, November 28, 2018. LINK
  5. Evangeline H, “Difference between Micro LED and Mini LED.” LEDinside,May 8, 2018. LINK
  6. Halliday, F. “MicroLED vs Mini-LED: What’s the difference?” PCWorld, September 11, 2018. LINK
  7. YiningChen, “Micro LED & Mini LED Market Expects Explosive Business Opportunities, with an Estimated market Value of $1.38 Billion by 2022”. LEDinside (a division of market research company TrendForce), June 20, 2018. LINK

LED TV, QLED TV with QDEF-CF, and QLED TV with QD-CF

Source: Environmentally friendly quantum-dot color filters for ultra-high-definition liquid crystal displays

Source: Samsung Displays – Public Information Display

QLED – Quantum Dot LED

QLED stands for Quantum Dot Light-Emitting Diode, also referred to as quantum dot-enhanced LCD screen. While similar in working principle to conventional LCDs, QLEDs are using the properties of quantum dot particles to advance color purity and improve display efficiency. Quantum dots are integrated with the backlight system of the LCD screen, most commonly with the help of Quantum Dot Enhancement Film (QDEF) that takes place of the diffuser film. Blue LEDs illuminate the film, and quantum dots output the appropriate color, based on their size.

OLED – Organic LED

OLED stands for Organic Light-Emitting Diode, which is self-emitting. Not all OLEDs are using the same tech though. The OLED technology used in phone screens is RGB-OLED, which is completely different from the White OLED (also referred to as W-OLED) used in TVs and large format displays.

RGB-OLED vs. White OLED

RGB-OLEDs use individual sub-pixels emitting red, green, and blue light. RGB-OLEDs yield excellent color reproduction but are unfit for performance requirements of large format displays. With the evolution of materials and a difference in use cases comparing to TVs, RGB-OLED is a preferred technology for the smartphone use.

White OLEDs, in turn, emit white light, which then is passed through a color filter to generate red, green, and blue—similar to how LCDs function. Modern W-OLED color filters use RGBW (red, green, blue, white) structure, adding an additional white sub-pixel to the standard RGB to improve on the power efficiency, enhance brightness, and to mitigate issues with the OLED burn-in. Although having more complex circuit requirements than LCDs (emission is current-driven rather than voltage-driven), W-OLEDs can be utilized for large-scale displays.

QD-OLED vs OLED vs QLED vs Mini LED TVs: What’s the difference?

Deepak SinghFebruary 2, 2021

Quantum Dot OLED TVs are expected to finally go real in 2021. As the name suggests, these TV displays will use Quantum Dot technology to enhance and improve the existing OLED panels. 

How exactly are QD-OLED displays different from current OLED display panels manufactured by LG Displays and from Samsungs existing QLED TVs? The next year will also see a surge in mini LED TVs which will be priced a little below OLED TVs. So let’s compare these different TV technologies to better understand which one is better and why. 

OLED on TVs and OLED on Phones are not the same 

To understand the difference between these display technologies and why they exist, it must first be cleared that the OLED displays on TVs are not the same as OLED displays on phones. 

On your phones, the OLED panels have red, green, and blue subpixels that are self-emissive or emit their own red, green, and blue colors – and can be individually powered on or powered off. 

Making similar OLED panels for large TVs with individual Red, Green and Blue subpixels, however, poses several manufacturing and longevity challenges. In fact, only one such TV was ever launched – the Samsung KE55S9C 55-inch UHD OLED- which was introduced in 2013. 

Samsung KE55S9C 55-inch UHD OLED TV with true RGB colors

The technology wasn’t scalable for larger resolution or bigger displays and thus Samsung shifted to Quantum Dots based QLED technology for its premium TVs. 

Meanwhile, LG Displays developed OLED for TVs where all subpixels are white and not RGB.

The white OLED light is achieved by using Blue and Yellow substrate. Different colors for four sub-pixels (R, G, B, W) are achieved by using a RGBW color filter layer over the essentially white OLED subpixels.  This works because a single color OLED panel is easier to manufacture and decays uniformly – which is to say that your TV will age to be less bright but the backplane light shall still remain uniformly blue or uniformly yellow. 

The color filter film used in front of OLED subpixels, however, is not an ideal solution. The filters work by blocking particular colors of light thus reducing brightness, and as the Blue OLED material decays over time, Red, Green, and Blue colors are affected differentially (the decay is not the same for all three colors resulting in color shifts, burn-in and other issues). 

QD OLED or Quantum Dot OLED TVs aim to fix these issues by using a quantum dots layer for color conversion instead of a color filter.

Also Read: Best 4K TVs to buy in India 

What are Quantum Dots and why they are better than color filters?

Quantum dots are small nanocrystals. When a high-energy light photon strikes quantum dots, they absorb it and emit a new photon. The color of this emitted photon depends on the size of the quantum dot – so manufacturers have to use the same material (just different sizes) for all colors, which makes manufacturing simpler and helps with uniform aging. 

Source: Nanosys

In TVs, Quantum Dots are excited by higher energy or lower wavelength light than the emission color of the dot. To excite green and red color quantum dots, TV manufacturers thus use blue light and for blue subpixels, they let the blue light pass through as-is.

The same result can perhaps be obtained by using blue, red and green quantum dots and exciting them using ultraviolet light.  However, Blue quantum dots are not as easy to develop as green and red (Samsung does have blue Quantum dot technology, but it is not yet being used commercially). 

Quantum dots act as an excellent color converter and have almost 100 percent quantum efficiency. Thus unlike color filters, the Quantum dots layer doesn’t block lights of particular wavelengths or colors and let the entire luminance pass through.

QD-OLED vs OLED: Why QD-OLED displays are better

QD-OLED TV Layers (source: Nanosys)
OLED TV layers

As mentioned above, color conversion in QD-OLED displays is done by quantum dots that are placed or patterned at a sub-pixel level over Blue OLEDs. 

So, we have a blue emissive layer in the backplane where all pixels are blue. And then green and red quantum dot materials are printed on pixels that are needed to be green or red. 

White OLED vs QD -OLED (Source: Nanosys)

Colors are converted on red sub-pixels by red quantum dots and green sub-pixel by green quantum dots. Using this technology, the end result is similar to what you’d get with individual Red, Green, and Blue sub-pixels as with AMOLED displays on phones. 

QD-OLED vs OLED color gamut

Quantum Dots as color converters are highly efficient and way better than color filters that can block up to 60% light. 

Another benefit of this implementation over color filter is that as the Blue OLED lights get dimmer with time, the red and green light getting out of the quantum dots will dim proportionally. 

So, over the lifetime of your TV, its display may get less bright but colors shall remain mostly unaffected. The use of Quantum dot also helps with wider color gamuts with fewer image artifacts, better brightness, and better HDR. 

OLED TVs today use LG Display panels that have a white pixel along with red, green, and blue sub-pixels (and are also referred to as White OLED). This is used for enhancing brightness but reduces color vibrance. Upcoming QD-OLED panels will, in a way, re-instate RGB OLED with deeper, brighter, and more vibrant colors. 

OLED technology is known to have problems with aging, but the current crop of OLED TVs handle this remarkably well. There are negligent chances that users will face issues like OLED burn-ins over a life span of 5 to 8 years. 

Disadvantages of QD-OLED Displays

We discussed a few theoretical advantages of QD OLED above and let’s now talk about some disadvantages of the technology. 

Samsung is currently developing QD OLED panels that we will see in the first wave of QD OLED televisions and they won’t be perfect.

One problem is that Quantum dots on the QD OLED TVs get excited by UV light falling on the TV from the outside. Secondly, Quantum Dot color conversion materials don’t always capture the entire blue light that is used to excite them and some of it may bleed into Red and Green subpixels. 

To counter these problems, Samsung Displays is likely to use some sort of color filter which is likely to be eliminated as we progress to second or third-generation QD-OLED panels. It remains to be seen how much brightness penalty is incurred meanwhile. 

QLED vs QD-OLED: What’s different?
QLED layers

Now that we have discussed how Quantum dots are enhancing existing OLED TVs, you might be wondering how the Quantum Dot technology is implemented on existing Samsung QLED TVs.

Unlike QD-OLED TVs, QLED TVs use Quantum dots as a backplane technology behind the LCD. 

A QLED TV works just like LCD TVs, but a Quantum Dot Enhancement Film( QDEF) is used in front of the Blue LED backlight to convert portions of the blue light to Red and Green in order to get pure White light. This helps enhance brightness and achieve a wider color gamut for better HDR performance.

QLED TVs are better at avoiding the backlight bleed into the display colors as compared to conventional LED or mini LED TVs. Samsung’s high-end QLED models can also get brighter than TV OLED displays. Color conversion is still done using a color filter in front of the LCD module. 

And what about Mini LEDs?

LED TVs don’t have self-emissive pixels and it’s not possible to turn off individual pixels. The LCD substrate merely blocks the white light from the backlight to portray blacks, resulting in slightly greyish blacks more noticeable in dark ambiance. The contrast and black level can however be improved by turning off a portion or zone of the backlight. 

That’s where mini LED TVs come in. These TVs have an array of mini LEDs behind the screen which can be individually turned off for a section of the screen. These mini LEDs don’t map pixels one to one, but having more zones helps with better local dimming control and thus enhances quality over conventional edge-lit LED displays. 

Manufacturers are working on adding quantum dot enhancements to microLED backlighting as well (similar to QD enhancements in QLED TVs). 

When will we see QD OLED TVs? 

Samsung Displays is manufacturing QD-OLED displays but Samsung Electronics isn’t keen on adopting the technology. That’s because Samsung has been marketing QLED as superior to OLED panels for years and transitioning back to OLED or OLED-based TVs will make them lose face. 

QD OLED panels are however being provided to a number of other manufacturers including Sony and we will most probably see QD-OLED TVs in 2021.

QD-BOLED

Source: Inkjet printed uniform quantum dots as color conversion layers for full-color OLED displays

Quantum dots (QDs) have shown great potential for next generation displays owing to their fascinating optoelectronic characteristics. In this work, we present a novel full-color display based on blue organic light emitting diodes (BOLEDs) and patterned red and green QD color conversion layers (CCLs). To enable efficient blue-to-green or blue-to-red photoconversion, micrometer-thick QD films with a uniform surface morphology are obtained by utilizing UV-induced polymerization. The uniform QD layers are directly inkjet printed on red and green color filters to further eliminate the residual blue emissions. Based on this QD-BOLED architecture, a 6.6-inch full-color display with 95% Broadcasting Service Television 2020 (BT.2020) color gamut and wide viewing-angles is successfully demonstrated. The inkjet printing method introduced in this work provides a cost-effective way to extend the applications of QDs for full-color displays.

My Related Posts

Color Science of Gem Stones

Nature’s Fantastical Palette: Color From Structure

Optics of Metallic and Pearlescent Colors

Color Change: In Biology and Smart Pigments Technology

Color and Imaging in Digital Video and Cinema

Digital Color and Imaging

On Luminescence: Fluorescence, Phosphorescence, and Bioluminescence

On Light, Vision, Appearance, Color and Imaging

Key Sources of Research

Light responsive liquid crystal soft matters: structures, properties, and applications

Dae-Yoon Kim & Kwang-Un Jeong

Dae-Yoon Kim & Kwang-Un Jeong (2019)

Liquid Crystals Today, 28:2, 34-45, DOI: 10.1080/1358314X.2019.1653588

https://www.tandfonline.com/doi/pdf/10.1080/1358314X.2019.1653588?needAccess=true

LIQUID CRYSTAL DISPLAY APPLICATIONS: Past, Present & Future

Joseph A Castellano PhD

Liquid Crystals Today, 1:1, 4-6, DOI: 10.1080/13583149108628568

https://www.tandfonline.com/doi/pdf/10.1080/13583149108628568?needAccess=true

The fiftieth anniversary of the liquid crystal display 

J. Cliff Jones

Liquid Crystals Today, 27:3, 44-70, DOI: 10.1080/1358314X.2018.1529129

https://www.tandfonline.com/doi/pdf/10.1080/1358314X.2018.1529129?needAccess=true

Advanced liquid crystal displays with supreme image qualities

Haiwei Chen & Shin-Tson Wu

Liquid Crystals Today, 28:1, 4-11, DOI: 10.1080/1358314X.2019.1625138

https://www.tandfonline.com/doi/pdf/10.1080/1358314X.2019.1625138?needAccess=true

Plenary Lecture. Some pictures of the history of liquid crystals

Hans Kelker  & Peter M. Knoll Pages 19-42 | Published online: 24 Sep 2006

https://www.tandfonline.com/doi/abs/10.1080/02678298908026350?src=recsys

Liquid crystal display and organic light-emitting diode display: present status and future perspectives

Hai-Wei Chen1, Jiun-Haw Lee2, Bo-Yen Lin2, Stanley Chen3 and Shin-Tson Wu1

Light: Science & Applications (2018) 7, 17168; doi:10.1038/lsa.2017.168

https://www.nature.com/articles/lsa2017168.pdf?origin=ppub

Going beyond the limit of an LCD’s color gamut 

Hai-Wei Chen1, Rui-Dong Zhu1, Juan He1, Wei Duan2, Wei Hu2, Yan-Qing Lu2, Ming-Chun Li3, Seok-Lyul Lee3, Ya-Jie Dong1,4 and Shin-Tson Wu1

Light: Science & Applications (2017) 6, e17043; doi:10.1038/lsa.2017.43

https://www.semanticscholar.org/paper/Going-beyond-the-limit-of-an-LCD’s-color-gamut-Chen-Zhu/523719d14139b9a9e8ada8c1599ac9aa8f67c8ec

An overview about monitors colors rendering

January 2010

TOADERE FLORIN, NIKOS E. MASTORAKIS

WSEAS Transactions on Circuits and Systems 9(1)

https://www.researchgate.net/publication/228666667_An_overview_about_monitors_colors_rendering

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.664.9593&rep=rep1&type=pdf

The History of Liquid-Crystal Displays

HIROHISA KAWAMOTO, FELLOW, IEEE

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.998.7087&rep=rep1&type=pdf

LCD (Liquid Crystal Display)

https://whatis.techtarget.com/definition/LCD-liquid-crystal-display

What is QLED? Samsung’s quantum dot TV tech explained

By Henry St Leger 

https://www.techradar.com/news/samsung-qled-samsungs-latest-television-acronym-explained

OLED vs QLED: the premium TV panel technologies compared

By Henry St Leger

https://www.techradar.com/news/oled-vs-qled

Liquid Crystals Displays

SCIFUN

http://www.scifun.org/chemweek/LCD/LCDs2019.html

The Liquid Crystal Display (LCD) Technology Turns 50

https://www.corning.com/worldwide/en/innovation/materials-science/glass/liquid-crystal-display-turns-50.html

Color Reproduction Characteristics of Liquid Crystal Display Panels and New Compensation Methods for Them

Yukio Okano* Nozomu Shiotani*

http://cgi.global.sharp/corporate/info/rd/tj3/pdf/9.pdf

COLOR IN DISPLAYS

WOO SUB SHIM

TC 706 COLOR SCIENCE

ADVISOR: DR. RENZO SHAMEY

OCTOBER 28 2008

Color science of nanocrystal quantum dots for lighting and displays

De Gruyter | 2013

https://www.degruyter.com/document/doi/10.1515/nanoph-2012-0031/html

Structural Colors for Display and E-paper Applications

L. Jay Guo

Department of Electrical Engineering and Computer Science The University of Michigan, Ann Arbor, Michigan, USA

https://deepblue.lib.umich.edu/bitstream/handle/2027.42/107993/sdtp00205.pdf;jsessionid=4ECB722ACF8896CFECA475935B750BD0?sequence=1

The Liquid Crystal Display Story

50 Years of Liquid Crystal R&D that lead The Way to the Future

Editors: Koide, Naoyuki (Ed.)

Book 2014

https://www.springer.com/gp/book/9784431548584

Chemistry On Display

Katherine Bourzac, contributor to C&EN

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4827559/

How Liquid Crystal Displays Work in an eWriter

By Monica Kanojia May 04, 2012

https://www.livescience.com/20104-boogie-board-ewriter-nsf-bts.html

Liquid Crystalline materials used in LCD display

https://madhavuniversity.edu.in/liquid-crystalline-materials.html

Electrophoretic liquid crystal displays: How far are we?

Susanne Klein

HP Laboratories HPL-2013-23

Who will win the future of display technologies?

By Hepeng Jia

National Science Review

5: 427–431, 2018 doi: 10.1093/nsr/nwy050

Advance access publication 23 April 2018

ENERGY EFFICIENT LED DISPLAYS


John Mani Kumar Jupalli

MS Thesis

Univ of Nevada 2010

From the theory of liquid crystals to LCD-displays

Nobel Price in Physics 1991: Pierre-Gilles de Gennes

Alexander Kleinsorge FHI Berlin, Dec. 7th 2004

Quantum Dot Display Technology and Comparison with OLED Display Technology

Askari Mohammad Bagher

Visual gamma correction for LCD displays

Kaida Xiao a,⇑, Chenyang Fu a, Dimosthenis Karatzas b, Sophie Wuerger a

Displays 32 (2011) 17–23

http://www.cvc.uab.es/people/dimos/papers/DISPLAYS2011_Xiao.pdf

Mini-LED, Micro-LED and OLED displays: present status and future perspectives

December 2020

Light: Science & Applications 9(1)

https://www.researchgate.net/publication/342274780_Mini-LED_Micro-LED_and_OLED_displays_present_status_and_future_perspectives

Mini-LED and Micro-LED: Promising Candidates for the Next Generation Display Technology

https://www.researchgate.net/publication/327470132_Mini-LED_and_Micro-LED_Promising_Candidates_for_the_Next_Generation_Display_Technology

Mini-LED, Micro-LED and OLED displays: present status and future perspectives

Yuge Huang, En-Lin Hsiang, Ming-Yang Deng & Shin-Tson Wu

Light: Science & Applications

volume 9, Article number: 105 (2020)

https://www.nature.com/articles/s41377-020-0341-9

https://www.semanticscholar.org/paper/Mini-LED%2C-Micro-LED-and-OLED-displays%3A-present-and-Huang-Hsiang/c6178d60899dc59e927e0c2e3f4336af6aecbe0f

Prospects and challenges of mini‐LED and micro‐LED displays

Yuge Huang Guanjun Tan SID
Fangwang Gou Ming‐Chun Li Seok‐Lyul Lee Shin‐Tson Wu

The Display Landscape of Mini- and MicroLEDs

Mon, January 21, 2019

https://www.radiantvisionsystems.com/blog/display-landscape-mini-and-microleds?gclid=EAIaIQobChMItvP3pdvR7gIVqf_ICh1jxwFJEAMYASAAEgL5PPD_BwE

CHALLENGES AND SOLUTIONS FOR ADVANCED MICROLED DISPLAYS

François Templier
Strategic Marketing, Displays and Displays Systems Optics and Photonics Department

CEA-LETI, Grenoble , France

How to Know the Differences Between an LED Display and LCD Monitor

Zach Cabading|May 11, 2020

https://store.hp.com/us/en/tech-takes/differences-between-led-display-and-lcd-monitor

Colorimetric Characterization of
Three Computer Displays (LCD and CRT)

Jason E. Gibson and Mark D. Fairchild January, 2000

http://www.sgidepot.co.uk/vw/PDFs/Colorimetric_Characterization.pdf

Display Considerations for Improved Night Vision Performance

Allan G. RempelRafał Mantiuk1,2 Wolfgang Heidrich1 1The University of British Columbia, 2Bangor University

Liquid Crystal Display: Environment & Technology Ankita Tyagi1, Dr. S. Chatterjee 2

1Centre for Development of Advanced Computing, New Delhi, India
2 Department of Electronics and Information Technology Ministry of Communication and Information Technology New Delhi, India

http://www.ijestr.org/IJESTR_Vol.%201,%20No.%207,%20July%202013/Liquid%20Crystal%20Display.pdf

A Study on Liquid Crystal Display (LCD) in Optoelectronics

Research Paper (Postgraduate), 2011

https://www.grin.com/document/213415

Color Converting Film With Quantum-Dots for the Liquid Crystal Displays Based on Inkjet Printing

Volume 11, Number 3, June 2019

Bing-Le Huang Tai-Liang Guo Sheng Xu Yun Ye. En-Guo Chen Zhi-Xian Lin

https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=8692730

Development of Color Resists Containing Novel Dyes for Liquid Crystal Displays

Liquid Crystal Display (LCD)

http://www.madehow.com/Volume-1/Liquid-Crystal-Display-LCD.html

James Fergason, a Pioneer in Advancing of Liquid Crystal Technology

Amelia Carolina Sparavigna

Understand color science to maximize success with LEDs 

https://www.ledsmagazine.com/home/article/16698622/understand-color-science-to-maximize-success-with-leds-magazine

Understand color science to maximize success with LEDs – part 2 

https://www.ledsmagazine.com/smart-lighting-iot/white-point-tuning/article/16695431/understand-color-science-to-maximize-success-with-leds-part-2-magazine

Understand color science to maximize success with LEDs – part 3 

https://www.ledsmagazine.com/smart-lighting-iot/white-point-tuning/article/16695448/understand-color-science-to-maximize-success-with-leds-part-3

Understand color science to maximize success with LEDs – part 4 

https://www.ledsmagazine.com/smart-lighting-iot/white-point-tuning/article/16695085/understand-color-science-to-maximize-success-with-leds-part-4-magazine

Full-color micro-LED display with high color stability using semipolar (20-21) InGaN LEDs and quantum-dot photoresist

High performance color‐converted micro‐LED displays

Fangwang Gou  | En‐Lin Hsiang  | Guanjun Tan  | Yi‐Fen Lan | Cheng‐Yeh Tsai | Shin‐Tson Wu

J Soc Inf Display. 2019;27:199–206.

Plasmonic Metasurfaces with Conjugated Polymers for Flexible Electronic Paper in Color

27 September 2016 https://doi.org/10.1002/adma.201603358

https://onlinelibrary.wiley.com/doi/epdf/10.1002/adma.201603358

Flexible electronic ‘paper’ display color spectrum rivals LED and uses less energy

http://www.chalmers.se/en/departments/chem/news/Pages/Bendable-electronic-paper-shows-full-colour-scale-.aspx

Plasmonic Color Makes a Comeback

ACS Cent. Sci. 2020, 6, 332−335

https://pubs.acs.org/doi/pdf/10.1021/acscentsci.0c00259

https://pubs.acs.org/doi/10.1021/acscentsci.0c00259

Performance of reflective color displays in Out Of Home applications

Etulipa

How Does a Color Changing LED Work

https://www.hunker.com/12000414/how-does-a-color-changing-led-work

The science of colour is upending our relationship with screens

https://www.wired.co.uk/article/project-crayon

Then and Now: The History of Display and LED Technology

Konica Minolta

https://sensing.konicaminolta.us/us/blog/then-and-now-the-history-of-display-and-led-technology/


A Novel RGBW Pixel for LED Displays

Year: 2008, Volume: 1, Pages: 407-411

https://www.computer.org/csdl/proceedings-article/icseng/2008/3331a407/12OmNywfKDb

LED Color Mixing: Basics and Background

Color Part 2:
Color Spaces and Color Perception 

by Roger N. Clark

https://clarkvision.com/articles/color-spaces/

Color Science

Cornell

http://www.cs.cornell.edu/courses/cs4620/2017sp/slides/26color.pdf

High performance color‐converted micro‐LED displays

Fangwang GouEn-Lin Hsiang, +3 authors S. Wu

Published 2019 Journal of The Society for Information Display

https://www.semanticscholar.org/paper/High-performance-color%E2%80%90converted-micro%E2%80%90LED-displays-Gou-Hsiang/b71e36bc6c999877040d88384598c45a8427925c

Choosing a Light and Color Measurement System for LEDs

https://www.radiantvisionsystems.com/learn/articles/choosing-light-and-color-measurement-system-leds

https://www.aerodefensetech.com/component/content/article/tb/pub/features/application-briefs/26901

Color in Electronic Display Systems

Advantages of Multi-primary Displays

Authors: Miller, Michael E.

Book, 2019

https://www.springer.com/gp/book/9783030028336

Color science of nanocrystal quantum dots for lighting and displays

2013

Talha Erdem and Hilmi Volkan Demir

Nanophotonics 2013; 2(1): 57–81

http://repository.bilkent.edu.tr/bitstream/handle/11693/12119/10.1515-nanoph-2012-0031.pdf?sequence=1&isAllowed=y

https://www.researchgate.net/publication/258807123_Color_science_of_nanocrystal_quantum_dots_for_lighting_and_displays

Full-Color Realization of Micro-LED Displays

Yifan Wu, Jianshe Ma, Ping Su, Lijun Zhang and Bizhong Xia

Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China

Nanomaterials 2020, 10(12), 2482; https://doi.org/10.3390/nano10122482

https://www.mdpi.com/2079-4991/10/12/2482/htm

Variation of LED Display Color Affected by Chromaticity and Luminance of LED Display Primary Colors

Xinyue Mao, Xifeng Zheng, Ruiguang Wang , Hongbin Cheng,1 and Yu Chen

Hindawi
Mathematical Problems in Engineering Volume 2020, Article ID 1612931, 14 pages

https://doi.org/10.1155/2020/1612931

Full-color micro-LED display with high color stability using semipolar (20-21) InGaN LEDs and quantum-dot photoresist

Vol. 8, No. 5 / May 2020 / Photonics Research

The Display Landscape of Mini- and MicroLEDs

2019 Radiant Visions

https://www.radiantvisionsystems.com/blog/display-landscape-mini-and-microleds?gclid=EAIaIQobChMItvP3pdvR7gIVqf_ICh1jxwFJEAMYASAAEgL5PPD_BwE

Flat screens show their true colors

Innovative pigments from BASF improve television image quality

https://www.basf.com/us/en/media/science-around-us/color-filter.html

THE HISTORY OF LC DISPLAYS

Merck KGaA

https://www.emdgroup.com/en/expertise/displays/solutions/liquid-crystals/history-of-lcd-displays.html

Comparative Evaluation of Color Characterization and Gamut of LCDs versus CRTs

Gaurav Sharma
Xerox Corp., MS0128-27E, 800 Phillips Rd., Webster, NY 14580

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.299.1580&rep=rep1&type=pdf

Calibrated color mapping between LCD and CRT displays: A case study

  • December 2005
  • Color Research & Application 30(6):438 – 447

DOI: 10.1002/col.20156

https://www.researchgate.net/publication/227604704_Calibrated_color_mapping_between_LCD_and_CRT_displays_A_case_study

Colorimetric characterization of the Apple studio display (Flat panel LCD)

Mark Fairchild David Wyble

The History of Liquid Crystal Display

https://www.thoughtco.com/liquid-crystal-display-history-lcd-1992078

Self-assembled plasmonics for angle-independent structural color displays with actively addressed black states

Daniel Franklin, Ziqian He, Pamela Mastranzo Ortega, Alireza Safaei, Pablo Cencillo-Abad,  Shin-Tson Wu, and Debashis Chanda

PNAS June 16, 2020 117 (24) 13350-13358; first published June 3, 2020; https://doi.org/10.1073/pnas.2001435117

https://www.pnas.org/content/117/24/13350

Liquid Crystals in Displays

MIT Open Course ware

Liquid Crystal Display (LCD)

http://www.madehow.com/Volume-1/Liquid-Crystal-Display-LCD.html

Liquid crystal display and organic light-emitting diode display: present status and future perspectives

Hai-Wei Chen1, Jiun-Haw Lee2, Bo-Yen Lin2, Stanley Chen3 and Shin-Tson Wu1

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6060049/

Color Converting Film With Quantum-Dots for the Liquid Crystal Displays Based on Inkjet Printing

B. Huang, T. Guo, S. Xu, Y. Ye, E. Chen and Z. Lin,

in IEEE Photonics Journal, vol. 11, no. 3, pp. 1-9, June 2019, Art no. 7000609,

doi: 10.1109/JPHOT.2019.2911308.

https://ieeexplore.ieee.org/document/8692730?denied=

CRT Versus LCD Monitors for Soft Proofifing: Quantitative and Visual Considerations

Chovancova

(2003). Master’s Theses. 4982.


https://scholarworks.wmich.edu/masters_theses/4982

A Color Gamut Description Algorithm for Liquid Crystal Displays in CIELAB Space


Bangyong Sun,1,2 Han Liu,2 Wenli Li,1 and Shisheng Zhou1

Hindawi Publishing Corporation
e Scientific World Journal
Volume 2014, Article ID 671964, 9 pages

http://dx.doi.org/10.1155/2014/671964

https://www.hindawi.com/journals/tswj/2014/671964/

Colour Characterisation of LCD Display Systems

Marjan Vazirian

PhD Thesis

School of Design The University of Leeds

http://etheses.whiterose.ac.uk/20850/1/Marjan_Vazirian_2018.pdf

Camouflaging metamaterials create the LCD color display of the future

The secret: precision placement of plasmonic aluminum nanorods

September 16, 2014

https://www.kurzweilai.net/camouflaging-metamaterials-create-the-lcd-color-display-of-the-future


Vivid, full-color aluminum plasmonic pixels

Jana Olson, Alejandro Manjavacas, Lifei Liu, Wei-Shun Chang, Benjamin Foerster, Nicholas S. King, Mark W. Knight, Peter Nordlander, Naomi J. Halas, and Stephan Link


PNAS first published September 15, 2014; https://doi.org/10.1073/pnas.1415970111

Contributed by Naomi J. Halas, August 19, 2014 (sent for review June 16, 2014)

Who will win the future of display technologies?

By Hepeng Jia

National Science Review 5: 427–431, 2018

doi: 10.1093/nsr/nwy050

Advance access publication 23 April 2018

https://academic.oup.com/nsr/article/5/3/427/4982784

Wide color gamut LCD with a quantum dot backlight

Zhenyue Luo, Yuan Chen, and Shin-Tson Wu

Full-Color Realization of Micro-LED Displays 

by Yifan WuJianshe MaPing Su *Lijun Zhang and Bizhong Xia

Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China

Nanomaterials202010(12), 2482; https://doi.org/10.3390/nano10122482

Received: 25 October 2020 / Revised: 23 November 2020 / Accepted: 7 December 2020 / Published: 10 December 2020

https://www.mdpi.com/2079-4991/10/12/2482/htm

Color science of nanocrystal quantum dots for lighting and displays

DOI: 10.1515/nanoph-2012-0031

https://www.researchgate.net/publication/258807123_Color_science_of_nanocrystal_quantum_dots_for_lighting_and_displays

Plasmonic Color Makes a Comeback

The phenomenon behind the earliest photographs is inspiring new research in color printing and displays.

  • Rachel Brazil

ACS Cent. Sci. 2020, 6, 3, 332–335Publication Date:March 16, 2020

https://doi.org/10.1021/acscentsci.0c00259

https://pubs.acs.org/doi/10.1021/acscentsci.0c00259

Plasmonic Metasurfaces with Conjugated Polymers for Flexible Electronic Paper in Color

Kunli Xiong Gustav Emilsson Ali Maziz Xinxin Yang Lei Shao Edwin W. H. Jager. Andreas B. Dahlin

First published: 27 September 2016

 https://doi.org/10.1002/adma.201603358

https://onlinelibrary.wiley.com/doi/epdf/10.1002/adma.201603358

Merck KGaA Germany

https://www.emdgroup.com/en/company.html

Pigments for Color Filters Used in LCDs and OLED Displays(Functional Pigments)

DIC Global

https://www.dic-global.com/en/csr/special/2018/special01.html

Development of Color Resists Containing Novel Dyes for Liquid Crystal Displays

Sumitomo Chemical Co., Ltd.
IT-Related Chemicals Research Laboratory

Masato INOUE Toru ASHIDA

Flat screens show their true colors

BASF

https://www.basf.com/us/en/media/science-around-us/color-filter.html

Color filter-less technology of LED back light for LCD-TV – art. no. 68410G

DOI: 10.1117/12.760045

https://www.researchgate.net/publication/241574165_Color_filter-less_technology_of_LED_back_light_for_LCD-TV_-_art_no_68410G

Synthesis and Characterization of Modified Dyes for Dye-Based LCD Color Filters

Cheol Jun Song , Wang Yao  & Jae Yun Jaung Pages 115-124 | Published online: 16 Dec 2013

Molecular Crystals and Liquid Crystals
Volume 583, 2013 – Issue 1: Proceedings of the Advanced Display Materials and Devices 2012 (ADMD 2012)

https://www.tandfonline.com/doi/abs/10.1080/15421406.2013.852895

A study on the fluorescence property and the solubility of the perylene derivatives and their application on the LCD color filter

Jeong Yun Kim

https://s-space.snu.ac.kr/handle/10371/136759

Synthesis and characterization of novel triazatetrabenzcorrole dyes for LCD color filter and black matrix

JunChoi WoosungLee Jin Woong NamgoongTae-Min KimJae PilKim

Dyes and Pigments
Volume 99, Issue 2, November 2013, Pages 357-365

https://www.sciencedirect.com/science/article/abs/pii/S0143720813001976

HIGH EFFICIENCY AND WIDE COLOR GAMUT LIQUID CRYSTAL DISPLAYS

ZHENYUE LUO

2015 Univ of Central Florida PhD Thesis

http://etd.fcla.edu/CF/CFE0006225/Zhenyue_Luo_Dissertation.pdf

A Simple Filter Could Make LCDs More Efficient

The new approach wastes far less light, saving energy.by 

  • Katherine Bourzac
  • 2010

https://www.technologyreview.com/2010/08/30/200821/a-simple-filter-could-make-lcds-more-efficient/

Past, present, and future of WCG technology in display

Musun Kwak | Younghoon Kim | Sanghun Han | Ahnki Kim | Sooin Kim | Seungbeom Lee | Mike Jun | Inbyeong Kang

Color Team, Panel Performance Division, LG Display, LG Science Park, Seoul, Korea

Musun Kwak, Color Team, Panel Performance Division, LG Display, LG Science Park, Magokjungang, Gangseogu, 10‐ro, Seoul, Korea.
Email: musunkwak@lgdisplay.com

https://onlinelibrary.wiley.com/doi/pdf/10.1002/jsid.843

https://www.toppan.co.jp/electronics/english/display/lcd/structure/

Improving the Color Gamut of a Liquid-crystal Display by Using a Bandpass Filter

Yan Sun1, Chi Zhang1, Yanling Yang1, Hongmei Ma1, and Yubao Sun1,2

Current Optics and Photonics 

ISSN: 2508-7266(Print) / ISSN: 2508-7274(Online) 

Vol. 3, No. 6, December 2019, pp. 590-596

Environmentally friendly quantum-dot color filters for ultra-high-definition liquid crystal displays

Yun-Hyuk Ko, Prem Prabhakaran, Sinil Choi, Gyeong-Ju Kim, Changhee Lee & Kwang-Sup Lee

Scientific Reports volume 10, Article number: 15817 (2020)

https://www.nature.com/articles/s41598-020-72468-8

Color filter technology for liquid crystal displays

Ram W Sabnis

Displays

Volume 20, Issue 3, 29 November 1999, Pages 119-129

https://www.sciencedirect.com/science/article/abs/pii/S014193829900013X

Designs of High Color Purity RGB Color Filter for Liquid Crystal Displays Applications Using Fabry–Perot Etalons

DOI: 10.1109/JDT.2011.2172914

https://www.researchgate.net/publication/239766666_Designs_of_High_Color_Purity_RGB_Color_Filter_for_Liquid_Crystal_Displays_Applications_Using_Fabry-Perot_Etalons

Synthesis of yellow pyridonylazo colorants and their application in dye–pigment hybrid colour filters for liquid crystal display

Jong Min Park, Chang Young Jung, Wang Yao, Cheol Jun Song and Jae Yun Jaung*

Department of Organic and Nano Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul, 133791, South Korea
Email: jjy1004@hanyang.ac.kr

Received: 9 June 2015; Accepted: 29 September 2015

https://www.researchgate.net/publication/312418853_Synthesis_of_yellow_pyridonylazo_colorants_and_their_application_in_dye-pigment_hybrid_colour_filters_for_liquid_crystal_display

A study on the fluorescence property and the solubility of the perylene derivatives and their application on the LCD color filter

Jeong Yun Kim 2017

https://s-space.snu.ac.kr/handle/10371/136759

Colour filters for LCDs

K.Tsuda

Dai Nippon Printing Co. Ltd, 1-5 Kiyokucho, Kuki City, Saitama Prefecture 346, Japan

Displays

Volume 14, Issue 2, April 1993, Pages 115-124

https://www.sciencedirect.com/science/article/abs/pii/014193829390078J

Liquid crystal display and organic light-emitting diode display: present status and future perspectives

Light: Science & Applications

volume 7, page17168(2018)

https://www.nature.com/articles/lsa2017168

Synthesis and Characterization of Modified Dyes for Dye-Based LCD Color Filters

Cheol Jun Song , Wang Yao  & Jae Yun Jaung Pages 115-124 | Published online: 16 Dec 2013

Molecular Crystals and Liquid Crystals
Volume 583, 2013 – Issue 1: Proceedings of the Advanced Display Materials and Devices 2012 (ADMD 2012)

https://www.tandfonline.com/doi/abs/10.1080/15421406.2013.852895

Textile materials inspired by structural colour in nature

Celina Jones, Franz J. Wortmann, Helen F. Gleeson and Stephen G. Yeatesc

RSC Adv., 2020,10, 24362-24367 

https://pubs.rsc.org/en/content/articlelanding/2020/ra/d0ra01326a#!divAbstract

Structure of Color Filters

Toppan Printing Company Japan

https://www.toppan.co.jp/electronics/english/display/lcd/structure/

Quantum Dot Conversion Layers Through Inkjet Printing

Ernest Lee, Ravi Tangirala, Austin Smith, Amanda Carpenter, Charlie Hotz, Heejae Kim, Jeff Yurek, Takayuki Miki*, Sunao Yoshihara*, Takeo Kizaki*, Aya Ishizuka*, Ikuro Kiyoto*

Nanosys, Inc., Milpitas, CA

*DIC Corporation, Sakura, Chiba, JAPAN

https://www.nanosysinc.com/white-papers/2018/11/28/quantum-dot-conversion-layers-through-inkjet-printing

Colors with plasmonic nanostructures: A full-spectrum review 

Applied Physics Reviews 6, 041308 (2019); https://doi.org/10.1063/1.5110051

Maowen Song1,2 Di Wang1 Samuel Peana1Sajid Choudhury1 Piotr Nyga1,3Zhaxylyk A. Kudyshev1Honglin Yu2Alexandra Boltasseva1Vladimir M. Shalaev1, and Alexander V. Kildishev1,a)

https://aip.scitation.org/doi/pdf/10.1063/1.5110051

Transmissive/Reflective structural color filters: theory and applications

Journal of Nanomaterials January 2014  Article No.: 6 

https://doi.org/10.1155/2014/212637

https://dl.acm.org/doi/abs/10.1155/2014/212637

Review of nanostructure color filters Felix Gildas and Yaping Dan*

University of Michigan–Shanghai Jiao Tong University Joint Institute, Shanghai, China

J. Nanophoton. 13(2), 020901 (2019), doi: 10.1117/1.JNP.13.020901.

http://yapingd.sjtu.edu.cn/upload/editor/file/20190708/20190708084242_36263.pdf

Nanostructured Color Filters: A Review of Recent Developments

Ayesha Shaukat,1,2Frazer Noble,1 and  Khalid Mahmood Arif1,*

Nanomaterials (Basel). 2020 Aug; 10(8): 1554.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7466596/

Bright and Vivid Diffractive-Plasmonic Structural Colors

https://pubs.acs.org/doi/10.1021/acsanm.9b02508

Transmissive metamaterial color filters

Yoshiaki Kanamori, Daisuke Ema, and Kazuhiro Hane

JSAP-OSA Joint Symposia 2017 Abstracts(Optical Society of America, 2017),paper 5p_A410_5

https://www.osapublishing.org/abstract.cfm?uri=JSAP-2017-5p_A410_5

Three-terminal RGB full-color OLED pixels for ultrahigh density displays

Scientific Reports volume 8, Article number: 9684 (2018) 

https://www.nature.com/articles/s41598-018-27976-z

Application organic pigment for color filter of LCD

Emperor Chemicals China

https://pigmentpigment.com/news/application-organic-pigment-for-color-filter-of-lcd–9.html

Liquid-crystal tunable color filters based on aluminum metasurfaces

Zu-Wen Xie, Jhen-Hong Yang, Vishal Vashistha, Wei Lee, and Kuo-Ping Chen

Optics ExpressVol. 25,Issue 24,pp. 30764-30770(2017)

Preparation of Colour Filter Photo Resists for Improving Colour Purity in Liquid Crystal Displays by Synthesis of Polymeric Binder
and Treatment of Pigments

Chun Yoonand Jae-hong Choi

Department ofChemistry, Sejong University, Seoul 143-747, Korea. *E-mail: chuny@sejong.ac.kr ‘Department of Textile System Engineering, Kyungpook National University, Daegu 702-701, Korea Received May 04, 2009, Accepted July 03, 2009

Bull. Korean Chem. Soc. 2009, Vol. 30, No. 8

THE SCIENCE OF COLOR AND LIGHT

By Michael Cassera 9. June 2020

https://newsandviews.dataton.com/the-science-of-color-and-light

Image Display Technology

http://www.marcelpatek.com/LCD.html

Past, present, and future of WCG technology in display

Musun Kwak Younghoon Kim Sanghun Han Ahnki Kim Sooin Kim Seungbeom Lee Mike Jun Inbyeong Kang

 First published: 02 October 2019 

Volume27, Issue11 November 2019. Pages 691-699

https://onlinelibrary.wiley.com/doi/full/10.1002/jsid.843

Panel Technologies

Simon Baker, updated  17 March 2015

https://www.tftcentral.co.uk/articles/panel_technologies.htm

https://www.tftcentral.co.uk/articles/panel_technologies.htm

LED Backlighting

Simon Baker, 11 November 2010

https://www.tftcentral.co.uk/articles/led_backlighting.htm

The Evolution of LED Backlights

Author: Adam Simmons
Last updated: February 8th 2021

PCmonitors.info

OLED Production: Composition and Color Patterning Techniques

Last updated on January 22, 2020

https://www.findlight.net/blog/2020/01/22/oled-production-composition-and-color-patterning-techniques/

OLED Color Patterning Technologies

Book Author(s): Takatoshi TsujimuraFirst published: 04 March 2017 

OLED Display Fundamentals and Applications, Second Edition

https://onlinelibrary.wiley.com/doi/pdf/10.1002/9781119187493.ch5

OLED Technologies

Tohoku Pioneer Corporation

https://global.pioneer/en/corp/group/tohokupioneer/mainbusinesses/oled/introduction/

Directly Patterened 2645 PPI Full Color OLED Microdisplay for Head Mounted Wearables

DOI: 10.1002/sdtp.10805

https://www.researchgate.net/publication/303535486_62-1_Invited_Paper_Directly_Patterened_2645_PPI_Full_Color_OLED_Microdisplay_for_Head_Mounted_Wearables

The Progress of QD Color Filters

https://avantama.com/the-progress-of-qd-color-filters/

19.2: Color Filter Formulations for Full‐Color OLED Displays: High Color Gamut Plus Improved Efficiency and Lifetime

Margaret J. HelberPaula J. AlessiMitchell BurberrySteven EvansM. Christine BrickDonald R. DiehlRonald Cok

SID

First published: 05 July 2012 https://doi.org/10.1889/1.2785479

https://onlinelibrary.wiley.com/doi/pdf/10.1889/1.2785479

Can OLED displays be brighter?

Structure of Color Filters

Toyo Visual

https://www.toyo-visual.com/en/products/fpdcf/colorfilter.html

QLED vs. W-OLED: TV Display Technology Shoot-Out

Samsung Display

https://pid.samsungdisplay.com/en/printpdf/learning-center/blog/qled-vs-oled-tv-display-technology

Thin-film transistor-driven vertically stacked full- color organic light-emitting diodes for high- resolution active-matrix displays

Sukyung Choi 1, Chan-mo Kang1, Chun-Won Byun1, Hyunsu Cho1, Byoung-Hwa Kwon1, Jun-Han Han1, Jong-Heon Yang1, Jin-Wook Shin1, Chi-Sun Hwang 1, Nam Sung Cho1, Kang Me Lee1, Hee-Ok Kim1, Eungjun Kim2, Seunghyup Yoo2 & Hyunkoo Lee

Nat Commun. 2020; 11: 2732. Published online 2020 Jun 1.

doi: 10.1038/s41467-020-16551-8

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7264127/

QD-OLED vs OLED vs QLED vs Mini LED TVs: What’s the difference?

By Deepak Singh – Updated On 

Inkjet printed uniform quantum dots as color conversion layers for full-color OLED displays

Zhiping Hu,*abYongming Yin,  abMuhammad Umair Ali,  cWenxiang Peng,bShijie Zhang,bDongze Li,bTaoyu Zou,aYuanyuan Li,bShibo Jiao,bShu-jhih Chen,bChia-Yu Lee,bHong Menga  and  Hang Zhou

Nanoscale, 2020,12, 2103-2110 

https://pubs.rsc.org/en/content/articlelanding/2020/nr/c9nr09086j#!divAbstract

Understand RGB LED mixing ratios to realize optimal color in signs and displays

https://www.ledsmagazine.com/smart-lighting-iot/color-tuning/article/16695054/understand-rgb-led-mixing-ratios-to-realize-optimal-color-in-signs-and-displays-magazine

Mini-LED vs MicroLED – What Is The Difference?

BY ROB SHAFER OCTOBER 1, 2020

https://www.displayninja.com/mini-led-vs-microled/

The Progress of QD Color Filters

https://avantama.com/the-progress-of-qd-color-filters/

What are the different types of RGB LEDs?

https://www.lighting.philips.com/main/support/support/faqs/white-light-and-colour/what-are-the-different-types-of-rgb-leds

OLED Production: Composition and Color Patterning Techniques

https://www.findlight.net/blog/2020/01/22/oled-production-composition-and-color-patterning-techniques/

OLED Color Patterning Technologies

Book Author(s): Takatoshi Tsujimura

First published: 04 March 2017 

OLED Display Fundamentals and Applications, Second Edition

Can OLED display be brighter?

Structure of Color Filters

https://www.toyo-visual.com/en/products/fpdcf/colorfilter.html

QD-OLED vs OLED vs QLED vs Mini LED TVs: What’s the difference?

By Deepak Singh – Updated On 

Liquid crystal display and organic light-emitting diode display: present status and future perspectives

Hai-Wei Chen1, Jiun-Haw Lee2, Bo-Yen Lin2, Stanley Chen3 and Shin-Tson Wu1

Light: Science & Applications (2018) 7, 17168; doi:10.1038/lsa.2017.168

Beyond OLED: Efficient Quantum Dot Light-Emitting Diodes for Display and Lighting Application

Yizhe Sun 1 2Yibin Jiang 2 3Xiao Wei Sun 2Shengdong Zhang 1Shuming Chen 2

https://pubmed.ncbi.nlm.nih.gov/30698895/

Full-Color Realization of Micro-LED Displays

Yifan Wu 1Jianshe Ma 1Ping Su 1Lijun Zhang 1Bizhong Xia 1

Nanomaterials (Basel)
. 2020 Dec 10;10(12):2482.

doi: 10.3390/nano10122482.

https://pubmed.ncbi.nlm.nih.gov/33322057/

Color Converting Film With Quantum-Dots for the Liquid Crystal Displays Based on Inkjet Printing

Volume 11, Number 3, June 2019
IEEE Photonics Journal 

Bing-Le Huang Tai-Liang Guo Sheng Xu Yun Ye. En-Guo Chen Zhi-Xian Lin

https://ieeexplore.ieee.org/document/8692730?denied=

Who will win the future of display technologies?

By Hepeng Jia

National Science Review. 5: 427–431, 2018

doi: 10.1093/nsr/nwy050

https://academic.oup.com/nsr/article/5/3/427/4982784

Wide color gamut LCD with a quantum dot backlight

Zhenyue Luo, Yuan Chen, and Shin-Tson Wu

Optics Express > Volume 21 > Issue 22 > Page 26269

Prospects and challenges of mini‐LED and micro‐LED displays

Yuge Huang | Guanjun Tan | Fangwang Gou | Ming‐Chun Li2 | Seok‐Lyul Lee | Shin‐Tson Wu

J Soc Inf Display. 2019;27:387–401.

Full-color micro-LED display with high color stability using semipolar (20-21) InGaN LEDs and quantum-dot photoresist

Sung-Wen Huang Chen, Yu-Ming Huang, Konthoujam James Singh, Yu-Chien Hsu, Fang-Jyun Liou, Jie Song, Joowon Choi, Po-Tsung Lee, Chien-Chung Lin, Zhong Chen, Jung Han, Tingzhu Wu, and Hao-Chung Kuo

Photonics Research > Volume 8 > Issue 5 > Page 630

Full-Color Realization of Micro-LED Displays

by Yifan Wu, Jianshe Ma, Ping Su *OrcID, Lijun Zhang and Bizhong Xia

Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China

Nanomaterials 2020, 10(12), 2482; https://doi.org/10.3390/nano10122482

https://www.mdpi.com/2079-4991/10/12/2482/htm

Color science of nanocrystal quantum dots for lighting and displays

February 2013. Nanophotonics 2(1):57-81
DOI: 10.1515/nanoph-2012-0031

Project: Colloidal organic and inorganic nanoparticles for lighting and displays

https://www.researchgate.net/publication/258807123_Color_science_of_nanocrystal_quantum_dots_for_lighting_and_displays

High performance color‐converted micro‐LED display

Fangwang Gou | En‐Lin Hsiang  | Guanjun Tan  | Yi‐Fen Lan | Cheng‐Yeh Tsai | Shin‐Tson Wu

QD-OLED

https://www.oled-info.com/qd-oled

Environmentally friendly quantum-dot color filters for ultra-high-definition liquid crystal displays

Scientific Reports volume 10, Article number: 15817 (2020)

https://www.nature.com/articles/s41598-020-72468-8

Color filter technology for liquid crystal displays

Ram W Sabnis

Displays
Volume 20, Issue 3, 29 November 1999, Pages 119-129

https://www.sciencedirect.com/science/article/abs/pii/S014193829900013X

Stretchable and reflective displays: materials, technologies and strategies

Do Yoon Kim, Mi-Ji Kim, Gimin Sung & Jeong-Yun Sun

Nano Convergence volume 6, Article number: 21 (2019)

https://nanoconvergencejournal.springeropen.com/articles/10.1186/s40580-019-0190-5

LTPS LCD

https://www.pcmag.com/encyclopedia/term/ltps-lcd

LCD Basics

https://www.j-display.com/english/technology/lcdbasic.html

Characterization of TFT and LTPS TFT-LCD Display Panels by Spectroscopic Ellipsometry

https://www.horiba.com/en_en/applications/information-technology/semiconductors/display-technologies/characterization-of-tft-and-ltps-tft-lcd-display-panels-by-spectroscopic-ellipsometry/

Display technology explained: A-Si, LTPS, amorphous IGZO, and beyond

LTPS Process

AUO

https://auo.com/en-global/TFT-LCD_Introduction/index/LTPS_TFT_LCD

What Is An LTPS LCD?

https://www.electronicsforu.com/technology-trends/learn-electronics/ltps-lcd

Mini-LED vs MicroLED – What Is The Difference?

BY ROB SHAFER. OCTOBER 1, 2020

https://www.displayninja.com/mini-led-vs-microled/

LIQUID CRYSTAL DISPLAY APPLICATIONS Past, Present & Future

by Joseph A Castellano, PhD Stanford Resources Inc.
PO Box 20324, San Jose, CA 95160

https://www.tandfonline.com/doi/pdf/10.1080/13583149108628568?needAccess=true

The fiftieth anniversary of the liquid crystal display,

J. Cliff Jones (2018)

Liquid Crystals Today, 27:3, 44-70,

DOI: 10.1080/1358314X.2018.1529129

https://www.tandfonline.com/doi/pdf/10.1080/1358314X.2018.1529129?needAccess=true

Plenary Lecture. Some pictures of the history of liquid crystals, 

Hans Kelker & Peter M. Knoll (1989) 

Liquid Crystals, 5:1, 19-42, DOI: 10.1080/02678298908026350

Liquid crystal display and organic light-emitting diode display: present status and future perspectives

Hai-Wei Chen1, Jiun-Haw Lee2, Bo-Yen Lin2, Stanley Chen3 and Shin-Tson Wu1

Light: Science & Applications (2018) 7, 17168; doi:10.1038/lsa.2017.168; 

https://www.nature.com/articles/lsa2017168.pdf?origin=ppub

An overview about monitors colors rendering

https://www.researchgate.net/publication/228666667_An_overview_about_monitors_colors_rendering

The History of Liquid-Crystal Displays

HIROHISA KAWAMOTO, FELLOW, IEEE

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.998.7087&rep=rep1&type=pdf

From the theory of liquid crystals to LCD-displays

Nobel Price in Physics 1991: Pierre-Gilles de Gennes

Alexander Kleinsorge FHI Berlin, Dec. 7th 2004

Mini-LED, Micro-LED and OLED displays: present status and future perspectives

Light: Science & Applications volume 9, Article number: 105 (2020) 

https://www.nature.com/articles/s41377-020-0341-9

OLED vs QLED: the premium TV panel technologies compared

https://www.techradar.com/news/oled-vs-qled

The Liquid Crystal Display (LCD) Technology Turns 50

https://www.corning.com/worldwide/en/innovation/materials-science/glass/liquid-crystal-display-turns-50.html

COLOR IN DISPLAYS

The Liquid Crystal Display Story

50 Years of Liquid Crystal R&D that lead The Way to the Future

Editors: Koide, Naoyuki (Ed.)

2014

https://www.springer.com/gp/book/9784431548584

Chemistry On Display

Katherine Bourzac, contributor to C&EN

Mini-LED, Micro-LED and OLED displays: present status and future perspectives

DOI: 10.1038/s41377-020-0341-9

https://www.researchgate.net/publication/342274780_Mini-LED_Micro-LED_and_OLED_displays_present_status_and_future_perspectives

Mini-LED and Micro-LED: Promising Candidates for the Next Generation Display Technology

DOI: 10.3390/app8091557

https://www.researchgate.net/publication/327470132_Mini-LED_and_Micro-LED_Promising_Candidates_for_the_Next_Generation_Display_Technology

CHALLENGES AND SOLUTIONS FOR ADVANCED MICROLED DISPLAYS

François Templier
Strategic Marketing, Displays and Displays Systems Optics and Photonics Department

CEA-LETI, Grenoble , France

Three-terminal RGB full-color OLED pixels for ultrahigh density displays

Scientific Reports volume 8, Article number: 9684 (2018)

https://www.nature.com/articles/s41598-018-27976-z

Past, present, and future of WCG technology in display

Musun KwakYounghoon KimSanghun HanAhnki KimSooin Kim… See all authors 

First published: 02 October 2019

 https://doi.org/10.1002/jsid.843

https://onlinelibrary.wiley.com/doi/full/10.1002/jsid.843

Thin-film transistor-driven vertically stacked full-color organic light-emitting diodes for high-resolution active-matrix displays

Sukyung Choi,1Chan-mo Kang,1Chun-Won Byun,1Hyunsu Cho,1Byoung-Hwa Kwon,1Jun-Han Han,1Jong-Heon Yang,1Jin-Wook Shin,1Chi-Sun Hwang,1Nam Sung Cho,1Kang Me Lee,1Hee-Ok Kim,1Eungjun Kim,2Seunghyup Yoo,2 and  Hyunkoo Lee1,3

Nat Commun. 2020; 11: 2732. Published online 2020 Jun 1. 

doi: 10.1038/s41467-020-16551-8

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7264127/

Realizing Rec. 2020 color gamut with quantum dot displays

Ruidong Zhu,1 Zhenyue Luo,1 Haiwei Chen,1 Yajie Dong,1,2 and Shin-Tson Wu1,*

1CREOL, The College of Optics and Photonics, University of Central Florida, Orlando, Florida 32816, USA 2NanoScience Technology Center, University of Central Florida, Orlando, Florida 32826, USA

Full-color micro-LED display with high color stability using semipolar (20-21) InGaN LEDs and quantum-dot photoresist

SUNG-WEN HUANG CHEN,1 YU-MING HUANG,1,2 KONTHOUJAM JAMES SINGH,1 YU-CHIEN HSU,1 FANG-JYUN LIOU,1 JIE SONG,3 JOOWON CHOI,3 PO-TSUNG LEE,1 CHIEN-CHUNG LIN,2
ZHONG CHEN,4 JUNG HAN,5 TINGZHU WU,4,6 AND HAO-CHUNG KUO1,7

Vol. 8, No. 5 / May 2020 / Photonics Research

Color Science of Gem Stones

Color Science of Gem Stones

Key Terms

  • Iridescence Orient
  • Play-of-color Labradorescence
  • Chatoyancy (“cat’s-eye”) Asterism
  • Adularescence
  • Aventurescence
  • Change-of- color (“Alexandrite effect”)
  • Pearlescence
  • Opalescence

Causes of Color in Gemstones

Sourcez: AN UPDATE ON COLOR IN GEMS. PART 1: INTRODUCTION AND COLORS CAUSED BY DISPERSED METAL IONS

Three most common causes of color in gem materials:

  • Dispersed metal ions
  • Charge transfers and other processes that involve multiple ions, and colorcenters.
  • Coloration that are less often seen in gems, such as those that result from physical phenomena (asin opal) or from semiconductor-like properties (as in natural blue diamond).

Source: http://www.scifun.org/chemweek/ColorOfGemstones2017.pdf

THE COLORS OF GEMSTONES

The most common cause of color in gemstones is the presence of a small amount of a transition metal ion. These transition metal ions have an incomplete set of 3electrons. Changes in the energy of these electrons correspond to the energy of visible light. When white light passes through a colored gemstone or is reflected by it, some of the energy of the visible light is absorbed, causing 3electrons in the transition metal ion to undergo an energy change. The light that is transmitted or reflected appears colored, because those colors corresponding to 3d– electron energy transitions have been absorbed. The table lists several common gemstones, their chemical compositions, colors, and the origins of these colors.

A ruby is a crystal of alumina, aluminum oxide, containing a trace of chromium(III) ions replacing some of the aluminum ions. In ruby, each Al3+ ion and Cr3+ ion is surrounded by six oxide ions in an octahedral arrangement.

GemFormulaColorOrigin of color
RubyAl2O3RedCr3+ replacing Al3+ in octahedral sites
EmeraldBe3Al2(SiO3)6page1image48667408 page1image48670688Greenpage1image48674080Cr3+ replacing Al3+ in octahedral site
AlexandriteAl2BeO4page1image48684352 page1image48679952Red/Greenpage1image46942720Cr3+ replacing Al3+ in octahedral site
GarnetMg3Al2(SiO4)3page1image46978464 page1image46979040Redpage1image46980384Fe2+ replacing Mg2+ in 8- coordinate site
page1image47140576 page1image47141088PeridotMg2SiO4Yellow-greenFe2+ replacing Mg2+ in 6- coordinate site
page1image47154784 page1image47155296T ourmalinepage1image47156576 page1image47157088Na3Li3Al6(BO3)3(SiO3)6F4PinkMn2+ replacing Li+ and Al3+ in octahedral site
TurquoiseAl6(PO4)4(OH)84H2OBlue-greenCu2+ coordinated to 4 OH and 2 H2O
Sapphirepage1image88097760 page1image88100240Al2O3BlueIntervalence transition between Fe2+ and Ti4+ replacing Al3+ in adjacent octahedral sites

This arrangement splits the five 3orbitals of Cr3+ into two sets, the dxy, dxz, dyz orbitals and the dx2-y2 and dz2 orbitals. These two sets have different energies. The energy difference between these sets corresponds to the energy of visible light. When white light strikes a ruby, the gem absorbs the light of energy corresponding to the transition of an electron from the lower-energy set of 3orbitals to the higher-energy set. The ruby reflects or transmits the remainder of the light. Because this light is deficient in some energies (those that were absorbed), the light appears colored.

The origin of the color of emeralds is similar to that of the color of rubies. However, the bulk of an emerald crystal is composed of beryl, beryllium aluminum silicate, instead of the alumina which forms rubies. The color is produced by chromium(III) ions, which replace some of the aluminum ions in the crystal. In emeralds, the Cr3+ is surrounded by six silicate ions, rather than the six oxide ions in ruby. These silicate ions also split the 3orbitals of Cr3+ into two sets. However, the magnitude of the energy difference between the sets is different from that produced by the oxide ions in ruby. Therefore, the color of emeralds is different from that of ruby.

Chromium(III) also produces color in alexandrite. The color of this gem is very unusual, because in bright sunlight it appears green, but in incandescent light it appears red. This unusual behavior is a result of the way human vision works. Our eyes are most sensitive to green light. Alexandrite reflects both green and red light. In bright sunlight, the proportion of green light is greater than it is in the light from an incandescent lamp. The light reflected by alexandrite in bright sunlight is rich in green light, to which our eyes are most sensitive, and we perceive the gem as green. The light reflected by alexandrite in incandescent light is much richer in red, and we see the stone as red under these conditions.

Energy transition of the 3orbitals of other transition metal ions are responsible for the colors of other gemstones. Iron(II) produces the red of garnets and the yellow-green of peridots. Manganese(II) is responsible for the pink coloration of tourmaline, and copper(II) colors turquoise.

In some gemstones, the color is caused not by energy changes in a single transition metal ion, but by the exchange of electrons between two adjacent transition metal ions of differing oxidation states. The energy needed to transfer an electron from one ion to another corresponds to the energy of visible light. An example is sapphire. The bulk of sapphire is alumina, as in rubies, but some adjacent pairs of Al3+ ions are replaced by an Fe2+ ion and a Ti4+. When light of the appropriate energy strikes the crystal, energy is absorbed, and an electron moves from the Fe2+ to the Ti4+. Such a movement is called an intervalence transition. An intervalence transition is also responsible for the blue color of aquamarine. In aquamarine, adjacent Al3+ ions in beryl are replaced by an Fe2+ ion and an Fe3+ ion.

Not all gem colors are produced by transition metal ions. In some gemstones, the colors are produced by the presence of foreign atoms with a different number of valence electrons than the ones they replace. These foreign atoms are called color centers. Because the replacement atoms have the wrong number of valence electrons, they can supply or receive an electron from another atom by an intervalence transition. These color centers are often produced by nuclear transformation. An example of such a transformation is the change of a radioactive carbon- 14 atom in diamond into a nitrogen atom through beta particle emission. This leaves an atom of nitrogen in place of the original carbon atom. The nitrogen atom has one more valence electron than the carbon atom. These nitrogen atoms are the cause of the coloration of blue and yellow diamonds. Color centers can be caused artificially as well, by irradiating the gem in a nuclear reactor. Many bright blue and bright yellow diamonds are produced artificially in this manner.

REFERENCES

Chemistry in Britain, 1983, page 1004.
Gems and Gemology, Volume 17, 1981, page 37. Scientific American, October 1980, page 124.

Precious Stones

  • The Diamond
  • The Pearl
  • The Ruby
  • The Sapphire
  • The Emerald
  • The Oriental Cateye
  • The Alexandrite

RGB Colors of Gemstones

Blue Sapphire

Emerald

Ruby

Pearl

Tahitian Cultured Pearls

Diamond

Chrysoberyl (Oriental Cat’s Eye)

Alexandrite

Change in Color due to change in Illuminant

Semi Precious stones

  • The Amethyst
  • The Topaz
  • The Tourmaline
  • The Aquamarine
  • The Chrysoprase
  • The Peridot
  • The Opal
  • The Zircon
  • The Jade
  • The Garnet
  • The Lapis lazuli
  • The Moonstone
  • The Spinel
  • The Turquoise
  • The Agate
  • The Coral
  • The Citrine
  • The Onyx
  • The Chrysolite
  • The Amber
  • The Chrysoberyl
  • The Chalcedony
  • The Morganite
  • The Quartz
  • The Tanzanite

Amethyst

Topaz

London Blue Topaz

Blue Topaz

Tourmaline

The Aquamarine

Chrysoprase

The Peridot

The Opal

The Zircon

The Jade

Garnet

Lapis lazuli

The MoonStone

White Moonstone

Grey Moonstone

The Spinel

Turquoise

Agate

Red Agate

Citrine

Onyx Black

 Chalcedony

Rose Quartz

Color Chemistry of Gemstones

Healing Power of Gemstones and Crystals

Precious Stones and Semi Precious Stones arranged by Color

Precious and Semi Precious Stones and their characteristics

Birthstones by Month

Source: AN UPDATE ON COLOR IN GEMS. PART 3: COLORS CAUSED BY BAND GAPS AND PHYSICAL PHENOMENA

My Related Posts

Nature’s Fantastical Palette: Color From Structure

Optics of Metallic and Pearlescent Colors

Color Change: In Biology and Smart Pigments Technology

Color and Imaging in Digital Video and Cinema

Digital Color and Imaging

On Luminescence: Fluorescence, Phosphorescence, and Bioluminescence

On Light, Vision, Appearance, Color and Imaging

Key Sources of Research

COLOR IN GEMS: THE NEW TECHNOLOGIES

By George R. Rossman

https://www.semanticscholar.org/paper/Color-in-Gems%3A-The-New-Technologies-Rossman/6202b8b7c6bf5db326a4f173813f0e7bd4943c69

A Primer of Gemstones

Nova

https://www.pbs.org/wgbh/nova/article/gemstone-primer/

THE COLORS OF GEMSTONES

http://www.scifun.org/chemweek/ColorOfGemstones2017.pdf

An UPDATE ON COLOR IN GEMS. PART 1: INTRODUCTION AND COLORS CAUSED BY DISPERSED METAL IONS

By Emmanuel Fritsch and George R. Rossman

AN UPDATE ON COLOR IN GEMS. PART 2: COLORS INVOLVING MULTIPLE
ATOMS AND COLOR CENTERS

By Emmunuel Fritsch and George R. Rossinun

AN UPDATE ON COLOR IN GEMS. PART 3: COLORS CAUSED BY BAND GAPS AND
PHYSICAL PHENOMENA

By Emmanuel Fritsch and George R. Rossman

What Causes the Colour of Gemstones?

https://www.compoundchem.com/2014/06/29/what-causes-the-colour-of-gemstones/

Concerning Precious Stones and Jewels

Issued by Theodore A. Kohn & Son
Jewellers, New York

Palagems

http://www.palagems.com/concerning-precious-stones

7 Gemstone Legends That Will Blow Your Mind

Angara

GEOSC 110H: The Science of Gemstones

Penn State

Gemstones

LEE ANDREW GROAT

https://www.americanscientist.org/article/gemstones

Source of many Images

https://www.leibish.com/rings-jewelry/mozambique-no-heat-pigeon-blood-ruby-three-stone-ring-28510

The origins of color in minerals

KURT NASSAU

Bell Laboratories

Murray Hill, New Jersey 07974

American Mineralogist

Volume 63, pages 219-229, 1978

http://www.minsocam.org/MSA/collectors_corner/arc/color.htm

THE EARLY HISTORY OF GEMSTONE TREATMENTS

By Kurt Nassau

A QUICK GUIDE TO PEARL COLORS

DNA Fingerprinting of Pearls to Determine Their Origins

DOI: 10.1371/journal.pone.0075606

https://www.researchgate.net/publication/257840043_DNA_Fingerprinting_of_Pearls_to_Determine_Their_Origins

New developments in cultured pearl production: use of organic and baroque shell nuclei


January 2013
Authors: Laurent E Cartier University of Lausanne
Michael S. Krzemnicki at University of Basel

https://www.researchgate.net/publication/276269725_New_developments_in_cultured_pearl_production_use_of_organic_and_baroque_shell_nuclei

Blue Nile

https://www.bluenile.com/

Alexandrite Effect: Gemstones That Change Color in Different Light

http://www.geologyin.com/2017/03/alexandrite-effect-not-all-white-light.html

What is Chrysoprase?

http://geologylearn.blogspot.com/2016/12/chrysoprase-gemstone.html

10 World Famous Gemstones

PUBLISHED FRI, JUL 11 200810:07 AM EDTUPDATED WED, JAN 29 20143:11 PM EST

Jessica Mark

https://www.cnbc.com/2008/07/11/10-World-Famous-Gemstones.html

The Causes of Color

Kurt Nassau

Gem Diamonds: Causes of Colors

Hiroshi Kitawaki

Gemmological Association of All Japan, Ueno 5-25-11, Taito-ku, Tokyo 110-0005, Japan (Received 9 May 2007; accepted 1 August 2007)

New Diamond and Frontier Carbon Technology

Vol. 17, No. 3 2007 MYU Tokyo

NDFCT536_full.pdf

Causes of Color in Minerals and Gemstones 

Paul F. Hlava, Sandia National Laboratories pfhlava@sandia.gov