Electrophoretic Display Pixel Segmentation for Reflectivity
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Solution Overview
Problem
Existing electrophoretic display devices with quad-type color filter structures suffer from reduced white reflection rates and resolution, particularly in color electrophoretic displays, due to the absence of a black matrix, leading to compromised color characteristics.
Innovation Solution
The implementation of thin-film transistors in a matrix form on a lower substrate, with pixel electrodes and side electrodes, a partition wall to divide the pixel region into unit pixels, and an electrophoretic fluid containing charged particles, along with a common electrode on the upper substrate, allows for improved reflectivity without reducing resolution by preventing color mixing and enabling vertical color drive.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a quad-type color filter structure without black matrix is used, then the white reflection rate is improved, but the color characteristics and resolution are compromised
Solution Approach 1:
The invention divides each pixel into multiple sub-pixels (red, green, blue, and white sub-pixels) with dedicated color filters. This segmentation allows each sub-pixel to have precise color characteristics while the white sub-pixel provides high reflection rate, resolving the contradiction between white reflection rate and color characteristics.
Solution Approach 2:
Different regions of the pixel array have different color filter configurations. Specifically, red, green, and blue sub-pixels have corresponding color filters for precise color reproduction, while white sub-pixels have no color filter for high reflection rate. This local differentiation resolves the contradiction between white reflection rate and color characteristics.
2Illumination intensity
If a quad-type color filter structure without black matrix is used, then the white reflection rate is improved, but the resolution is reduced
Solution Approach 1:
By segmenting each pixel into four distinct sub-pixels (red, green, blue, white) with precise spatial positioning, the invention maintains high resolution while enabling high white reflection rate through the white sub-pixel. The segmentation allows independent control and precise optical path management for each sub-pixel.
3Manufacturing precision
If color filters are added to red, green, and blue sub-pixels, then color characteristics are improved, but white reflection rate is reduced
Solution Approach 1:
The invention applies color filters locally only to red, green, and blue sub-pixels where color characteristics are needed, while leaving white sub-pixels without color filters to maintain high reflection rate. This local quality differentiation resolves the contradiction between color characteristics and white reflection rate.
Solution Approach 2:
By segmenting the pixel into colored sub-pixels (with color filters) and white sub-pixels (without color filters), the invention allows colored sub-pixels to provide color characteristics while white sub-pixels provide high reflection rate, resolving the contradiction between color characteristics and white reflection rate.
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 enhances the reflectivity of the electrophoretic display device while maintaining high resolution, enabling the production of lightweight, thin-profile color EPD panels with cost competitiveness and improved color characteristics.
Implementation Method 1
an electrophoretic display device is an image display device using a phenomenon that colloidal particles move to either one of the polarities when one pair of electrodes to which a voltage is applied are immersed into a colloidal solution
Implementation Method 2
When a voltage is applied to the pixel electrode, charged pigment particles are moved to the pixel electrode or an opposite electrode
Data Source
AI summary
Disclosed is an electrophoretic display device and a fabrication method thereof, and the electrophoretic display device may include a thin-film transistor formed on a lower substrate, a pixel electrode connected to the thin-film transistor, side electrodes formed at periphery of the pixel electrode, a partition wall formed on the side electrode, fluid including an electrophoretic particles formed between the partition walls, and an upper substrate adhered on the lower substrate and formed with a common electrode on the rear surface thereof.