Reflective and Absorption Electrode Layers for Electrophoretic Display Light Leakage
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Solution Overview
Problem
Electrophoretic display devices suffer from light leakage through the binder between microcapsules, which reduces contrast ratio and brightness, and lack a black matrix to block external light, leading to increased power consumption.
Innovation Solution
A display substrate with a reflective electrode layer made of chromium or molybdenum and an absorption electrode layer with an optical density of at least 3.6, such as chromium oxide or molybdenum oxide, is used to prevent light leakage, along with an opaque organic layer to absorb light and enhance contrast.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the size of microcapsules is reduced to reduce light leakage space, then light leakage is reduced, but collisions between adjacent microcapsules occur
Solution Approach 1:
The patent introduces a binder as an intermediary substance between adjacent microcapsules. This binder fills the gaps and prevents direct contact/collisions between microcapsules while maintaining the reduced microcapsule size that minimizes light leakage pathways.
Solution Approach 2:
The patent applies different properties to different regions: microcapsules are kept small in the display region to reduce light leakage, while the binder provides structural support and spacing in the interstitial regions between microcapsules, creating a differentiated functional structure.
2Object-affected harmful factors
If a black matrix is added to block external light, then light blocking is improved, but device complexity increases
Solution Approach 1:
The patent merges the light-blocking function with the existing electrode structure and substrate. The black matrix is integrated into the display substrate architecture, combining multiple functions (structural support, electrical connection, and light blocking) into a unified structure rather than adding a completely separate component.
Solution Approach 2:
The substrate and electrode structures are designed to serve multiple functions simultaneously: providing mechanical support, enabling electrical connections for electrophoretic operation, and blocking external light through the integrated black matrix regions.
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 solution effectively reduces light leakage and current leakage, improving the display quality by increasing brightness and contrast ratio while minimizing power consumption.
Implementation Method 1
a reflective electrode layer which reflects light
Implementation Method 2
an absorption electrode layer which absorbs light, and an optical density of the absorption electrode layer is greater than or equal to about 3.6
Data Source
AI summary
A display substrate includes an insulation substrate, a gate line formed on the insulation substrate, a data line formed on the insulation substrate and crossing the gate line, a switching element formed on the insulation substrate and electrically connected to the gate line and the data line, and a pixel electrode formed on the insulation substrate. The pixel electrode is electrically connected to the switching element and includes a reflective electrode layer which reflects light and an absorption electrode layer which absorbs light.