Capacitive Electrode Segmentation for Electrophoretic Display Leakage
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Solution Overview
Problem
Electrophoretic display devices with capacitive electrodes face issues of electric field leakage between adjacent pixel electrodes, leading to malfunction and display quality degradation.
Innovation Solution
A display device configuration featuring a multilayer scanning line with conductive layers, a capacitive portion in the same layer as the conductive layers, and inorganic insulating films between these components, which reduces parasitic capacitance and electric field leakage, ensuring uniform electric field intensity and suppressing malfunctions of the electrophoretic element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a capacitive electrode is formed substantially over the entire surface of the display portion with all pixel electrodes overlapping it, then the display device can achieve simple structure and ease of manufacture, but electric field leakage occurs in gaps between adjacent pixel electrodes causing malfunction and display quality degradation
Solution Approach 1:
The capacitive electrode is divided into multiple separate capacitive portions, each corresponding to one pixel electrode. This segmentation prevents electric field leakage between pixels while maintaining the capacitive function for each pixel, resolving the contradiction between manufacturing simplicity and display reliability.
Solution Approach 2:
The capacitive electrode structure is optimized locally for each pixel region. Each pixel has its own dedicated capacitive portion positioned directly beneath it, providing localized electric field control. This local optimization eliminates the electric field leakage problem that occurs with a continuous capacitive electrode while maintaining ease of manufacture through standardized pixel structures.
2Stability of the object's composition
If a capacitive electrode is formed substantially over the entire surface of the display portion, then the display device achieves uniform capacitive distribution, but electric field leakage between adjacent pixel electrodes causes malfunction
Solution Approach 1:
The continuous capacitive electrode is segmented into discrete capacitive portions, each aligned with a specific pixel electrode. This segmentation eliminates the harmful electric field leakage between adjacent pixels while maintaining uniform capacitive distribution across the display, as each pixel receives consistent capacitive coupling from its dedicated portion.
Solution Approach 2:
The harmful electric field leakage between pixels is extracted and eliminated by removing the continuous connection between capacitive portions. Each capacitive portion is electrically isolated from its neighbors, preventing the leakage paths that would otherwise form through a continuous capacitive electrode structure.
3Manufacturing precision
If pixel electrodes are placed close to each other to increase display resolution, then high-definition display is achieved, but electric field leakage in gaps between pixel electrodes increases causing malfunction
Solution Approach 1:
The capacitive electrode is segmented into discrete portions for each pixel, creating electrical isolation between adjacent pixels. This allows pixel electrodes to be placed close together for high resolution without the risk of electric field leakage between them, as each capacitive portion is independently controlled and isolated from its neighbors.
Solution Approach 2:
The segmented capacitive portions act as intermediaries between the common electrode and pixel electrodes. Each capacitive portion is positioned to provide controlled electric field coupling only to its corresponding pixel electrode, preventing electric field leakage to adjacent pixels even when they are closely spaced for high resolution.
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 configuration effectively suppresses electric field leakage, maintains display quality, and reduces manufacturing complexity and costs by integrating capacitive components with the conductive layers, ensuring reliable operation and high-definition display.
Implementation Method 1
the first inorganic insulating film 11 is located between the first conductive layer 121 and the second conductive layer 122 and between the first capacitive portion 111 and the second capacitive portion 112
Implementation Method 2
an electrophoretic element 20 located between the pixel electrode 21 and the common electrode 22
Data Source
AI summary
According to one embodiment, a display device includes a first conductive layer, a second conductive layer overlapping the first conductive layer, a first capacitive portion located in a same layer as the first conductive layer, a second capacitive portion located in a same layer as the second conductive layer and overlapping the first capacitive portion, a first inorganic insulating film located between the first conductive layer and the second conductive layer and between the first capacitive portion and the second capacitive portion, a drain electrode electrically connected to the second capacitive portion, a pixel electrode electrically connected to the drain electrode.