Grayscale Color Electronic Paper Two-Layer Structure
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Solution Overview
Problem
Current color electronic paper technologies face challenges with narrow color gamut, low grayscale levels, and high costs, particularly in terms of repeatability, temperature sensitivity, and reflectivity, limiting their application in cost-effective displays.
Innovation Solution
A two-layer structure comprising a base color layer and a grayscale adjusting layer, where the base color layer displays primary colors and the grayscale layer adjusts the grayscale levels, achieving high-level grayscale and wide color gamut through a combination of reflective and transmissive structures, with each layer having a steady state at zero electric field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If particle type color electronic paper is used, then color display capability is improved, but grayscale repeatability deteriorates
Solution Approach 1:
The pixel is divided into multiple sub-pixels, each containing particles of a single color (red, green, blue, cyan, magenta, yellow). This segmentation allows independent control of each color component, improving grayscale repeatability while maintaining color display capability through additive color mixing of the sub-pixels.
2Illumination intensity
If three-layer superposition of cholesteric liquid crystal is used, then color gamut is improved, but cost increases and reflectivity deteriorates
Solution Approach 1:
The patent replaces expensive cholesteric liquid crystal materials with conventional electrophoretic particles and color particles that are cheaper and more readily available. The system achieves color display through the combination of electrophoretic grayscale control and color particle distribution, eliminating the need for costly cholesteric liquid crystal layers while maintaining acceptable color gamut.
3Illumination intensity
If color particles are increased in a single pixel, then color gamut is improved, but motion sensitivity to temperature and waveform change deteriorates
Solution Approach 1:
By dividing the pixel into multiple sub-pixels with fewer particle types each, the system reduces the complexity of particle motion control. Each sub-pixel contains only red, green, blue, cyan, magenta, or yellow particles, making the electrophoretic motion less sensitive to temperature and waveform variations while still achieving wide color gamut through combination.
4Illumination intensity
If two-layer structure with base color layer and grayscale adjusting layer is used, then grayscale level and color gamut are improved, but device complexity increases
Solution Approach 1:
The patent combines the base color layer and grayscale adjusting layer into a single integrated electrophoretic display structure. Both layers use the same electrophoretic mechanism and can be controlled by a unified driving circuit, reducing overall device complexity despite the enhanced display capabilities. The color particles and grayscale particles work together in the same electrophoretic medium.
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 balances manufacturing complexity and cost, enabling high-standard color displays with improved grayscale and color gamut, suitable for applications like newspapers and magazines, while reducing overall costs and enhancing display performance.
Implementation Method 1
the base color layer is a reflective structure. When black or white or some color is displayed, the color is formed through reflecting the light transmitted through the grayscale adjusting layer.
Implementation Method 2
the grayscale adjusting layer is a transmissive structure. The light is incident in the base color layer through the grayscale adjusting layer
Data Source
Figure 1~2
Figure 3
AI summary
A grayscale color electronic paper, each pixel structural unit of the electronic paper comprising a base color layer (2) and a grayscale adjusting layer (1), the base color layer (2) being able to display two or more colors, the colors displayed by the grayscale adjusting layer (1) corresponding one to one to the colors displayed by the base color layer (2), and the base color layer (2) and the grayscale adjusting layer (1) having respective driving structures. The base color layer (2) can display colors such as black, white, red, green, blue, cyan, magenta and yellow; and the grayscale adjusting layer (1) has multi-level gray scales, each level of gray scale having a steady state at a zero electric field. The electronic paper balances the degree of difficulty in manufacturing a driving source device and a display structure, reduces manufacturing costs, can achieve a stable display in multi-level gray scales, has a good color gamut range, and can be applied to more application fields.