Electro-optical Switching Element with Micro Lens Array

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing electro-optical switching elements fail to achieve high luminance, clear visibility under bright ambient light conditions with low power consumption and a wide process window simultaneously due to compatibility issues between light emitting moieties and liquid crystal materials, leading to poor uniformity and inefficient light emission.

Innovation Solution

The electro-optical display incorporates a micro lens array as a light direction changing layer between the light reflection and switching layers, utilizing reflected ambient light and backlight light efficiently, with a light reflection layer that selectively reflects specific wavelengths and a light conversion layer that enhances chromaticity and suppresses short-wavelength light, while using cholesteric liquid crystals and organic/inorganic phosphors to control light transmission and emission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If light emitting moieties (laser dyes) are used in liquid crystal materials, then light emission capability is improved, but compatibility and uniformity deteriorate

Engineering Contradiction:
Improvelight emission capabilityVSAvoidcompatibility and uniformity
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent separates the light emitting function from the liquid crystal material by placing light emitting moieties in a distinct encapsulated structure (well or chamber) rather than mixing them throughout the liquid crystal medium. This segmentation prevents compatibility issues while maintaining light emission capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary encapsulated structure (well or chamber) that contains the light emitting moieties and separates them from the liquid crystal material. This intermediary structure allows light emission while preventing direct interaction that would cause compatibility and uniformity problems.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If conventional light conversion means are used, then wavelength shifting is achieved, but light efficiency and luminance deteriorate

Engineering Contradiction:
Improvewavelength conversion capabilityVSAvoidlight efficiency and luminance
Core Design Contradiction:
Adaptability or versatilityVSIllumination intensity

Solution Approach 1:

The patent uses fluorescent materials that absorb light at one wavelength and emit at another wavelength, effectively creating a copied version of the light at a different wavelength. This allows efficient wavelength conversion while maintaining high luminance through the fluorescent emission process.

Inventive Principle:
Principle #26Copying

3Illumination intensity

If high energy radiation (UV, blue light) is used for illumination, then light emission is improved, but material degradation and reliability worsen

Engineering Contradiction:
Improvelight emissionVSAvoidmaterial stability
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent converts the potentially harmful high energy UV/blue light into beneficial lower energy visible light through fluorescent wavelength conversion. The fluorescent materials absorb the high energy radiation and re-emit it at safer, lower energies while still providing sufficient illumination intensity.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

4Illumination intensity

If ambient light reflection is utilized, then visibility under bright conditions is improved, but device complexity increases

Engineering Contradiction:
Improvevisibility under bright ambient lightVSAvoidoptical element arrangement
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The patent designs the display device to perform multiple functions with the same optical components. The light reflecting layer and light direction changing layers work both with ambient light (reflecting it) and with backlight (directing it), allowing the device to adapt to different lighting conditions without requiring separate systems for each function.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration results in bright, clear images with low power consumption and improved uniformity, effectively addressing the limitations of previous technologies by optimizing light usage and emission across a wide range of ambient conditions.

Implementation Method 1

one light direction changing layer, namely a micro lens array, between the light reflection layer and the electro optical element

Methodology Applied
Scientific EffectLight refraction and focusing: Lens

Implementation Method 2

Said light reflection means is capable to selectively reflect light of particular wavelength region

Methodology Applied
Scientific EffectSelective light reflection: Reflection

Implementation Method 3

Electro-optical switching elements using a liquid crystal material with a helical structure... as lighting and/or reflecting material

Methodology Applied
Scientific EffectCholesteric liquid crystal selective reflection: Cholesteric Liquid Crystal

Implementation Method 4

a light conversion layer, which comprises one or more light emitting moieties... being capable to shift the wavelength of the light to longer values

Methodology Applied
Scientific EffectFluorescence wavelength conversion: Fluorescence

Implementation Method 5

being capable to convert the state of polarization of the light from non-polarized light either to linear polarized light or to circular polarized light

Methodology Applied
Scientific EffectPolarization conversion: Polarisation

Data Source

PatentEP2839335B1Electro-optical switching element and electro-optical display
Publication Date: 2019.04.03 MERCK PATENT GMBH
  • EP2839335B1 patent drawingFigure 1~2
  • EP2839335B1 patent drawingFigure 3(a)~4

AI summary

The present invention relates to electro-optical switching elements and displays comprising them. In particular, it relates to electro- optical switching elements comprising at least a light reflecting layer (1), a light switching layer (2), and a light conversion layer (3), which comprises one or more light emitting substances (4), in particular, a light reflecting layer (1), which selectively reflects visible light, a light controlling element (2) that controls the amount of light transmitted (6) and/or reflected (8) by the light reflecting layer (1), and a light converting layer (3) that shifts the wavelength of the light (6,8) transmitted by the light controlling element (2) to longer values. The displays give bright images under either bright or dark conditions with small power consumption. They are particularly suitable for so called liquid crystal, electronic paper (e-paper) and MEMS switching applications.