Electrophoretic Display Color Filter Extension for Fringe Field Control
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Solution Overview
Problem
Electrophoretic display devices face issues with color mixing and reduced brightness due to fringe electric fields influencing adjacent pixel areas, which deteriorate color reproducibility and reflection ratio.
Innovation Solution
The design includes a first substrate with pixel areas and a first electrode, a second substrate with a second electrode and a color filter, and an electrophoretic layer between them, where the color filter extends beyond the electrode, forming an electric field that minimizes fringe field influence on adjacent pixels, thereby preventing color mixing and improving color reproducibility and reflection ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the electrode and color filter are aligned precisely, then the device structure is simple, but fringe electric fields influence adjacent pixel areas causing color mixing and reduced brightness
Solution Approach 1:
The color filter is designed with different extension lengths in different directions: it extends beyond the electrode in the first direction (where no adjacent pixel exists) but not in the second direction (where adjacent pixels exist). This local differentiation ensures that fringe electric fields cannot couple adjacent pixels, while maintaining simple overall structure.
2Manufacturing precision
If the color filter extends beyond the electrode, then color mixing is prevented and color reproducibility improves, but manufacturing precision requirements increase
Solution Approach 1:
The color filter is segmented into different regions with different extension characteristics. The portion extending beyond the electrode is specifically designed to prevent fringe field coupling, while the portion aligned with the electrode maintains simple manufacturing. This segmentation allows precise control where needed without compromising ease of manufacture overall.
3Illumination intensity
If the electrode area is increased to improve brightness, then light emission area increases, but fringe electric field influence on adjacent pixels worsens
Solution Approach 1:
The color filter is designed with different extension lengths in different directions: it extends beyond the electrode in the first direction (where no adjacent pixel exists) but not in the second direction (where adjacent pixels exist). This local differentiation ensures that fringe electric fields cannot couple adjacent pixels, while maintaining simple overall structure.
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 color reproducibility and reflection ratio by reducing the impact of fringe electric fields on adjacent pixels, leading to improved image quality and reduced power consumption.
Implementation Method 1
The electrophoretic layer is disposed between the first substrate and the second substrate and is controlled by the electric field formed by the first electrode and the second electrode to display an image
Data Source
AI summary
An electrophoretic display (EPD) device and a method of manufacturing the EPD are disclosed. An EPD device includes a first substrate, a second substrate, and an electrophoretic layer. The first substrate includes a plurality of pixel areas, and each pixel area includes a first electrode. The second substrate faces the first substrate and includes a second electrode to form an electric field with the first electrode and a color filter corresponding to the first electrode. The electrophoretic layer is disposed between the first substrate and the second substrate and is controlled by an electric field formed by the first electrode and the second electrode to display an image. An end portion of the color filter extends beyond an end portion of the first electrode.