Electrophoretic Display Light Fastness Additive
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Solution Overview
Problem
Existing electrophoretic displays using organic pigments suffer from reduced long-term color stability due to exposure to ultraviolet and visible light, which affects the quality of images over time.
Innovation Solution
Incorporating an electron acceptor molecule, such as a substituted 1,4-benzoquinone, into the electrophoretic medium of the display, which improves the light fastness of the color electro-optic display images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If organic pigment particles are used in electrophoretic displays, then color saturation and visual quality are improved, but long-term color stability deteriorates due to light exposure
Solution Approach 1:
The patent introduces an electron acceptor molecule as an intermediary substance in the electrophoretic medium. This mediator captures electrons generated by photoexcitation of organic pigments, preventing electron transfer between pigment molecules that would otherwise cause photochemical degradation. The electron acceptor thus protects the organic pigments while allowing them to maintain their color saturation.
Solution Approach 2:
The patent converts the harmful effect of light exposure (which generates electrons that degrade pigments) into a beneficial process by introducing electron acceptors. These acceptors deliberately capture the photo-generated electrons, transforming the degradation mechanism into a protected state where the pigments remain stable under light exposure while maintaining their visual properties.
2Ease of operation
If electrophoretic medium contains charged pigment particles, then display functionality is achieved, but light fastness deteriorates due to photochemical reactions
Solution Approach 1:
The electron acceptor molecule serves as a protective intermediary between light and the charged pigment particles. It intercepts electrons generated during photoexcitation, preventing these electrons from participating in harmful photochemical reactions that would degrade the pigment particles and reduce light fastness.
Solution Approach 2:
The patent modifies the chemical environment of the electrophoretic medium by adding electron acceptor molecules. This changes the electron transfer parameters and redox conditions in the medium, creating a protective chemical atmosphere that prevents photochemical degradation while maintaining the electrical functionality of the charged pigment particles.
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
The addition of the electron acceptor significantly enhances the long-term color quality and stability of the display images, reducing color gamut loss when exposed to light.
Implementation Method 1
Incorporating an electron acceptor molecule, such as a substituted 1,4-benzoquinone, into the electrophoretic medium of the display, which improves the light fastness of the color electro-optic display images
Implementation Method 2
The electrophoretic medium comprises a plurality of first type of charged pigment particles, a plurality of second type of charge pigment particles, a light fastness additive, and a non-polar liquid
Data Source
AI summary
A color electro-optic display is disclosed that comprises an electrophoretic medium including charged pigment particles, a light fastness additive, and a non-polar solvent, an organic electroactive compound, and a non-polar liquid. The light fastness additive is an electron acceptor and it improves the light fastness of the color electrophoretic display.