Shield Electrode Outer Surface Placement for LCD Charging Suppression
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Solution Overview
Problem
Liquid crystal display devices face issues with display quality degradation and manufacturing yield due to static electricity charging of the counter-substrate, alignment defects of liquid crystal molecules, and contamination by electrically conductive foreign matter, particularly when shield electrodes are disposed on the inner or outer surfaces of the counter-substrate.
Innovation Solution
A liquid crystal display device design where a shield electrode is positioned on the outer surface of the counter-substrate with its end portion exposed along at least one side, preventing static electricity charging and contamination by ensuring the shield electrode does not overlap cutting lines during substrate cutting, thus preventing short-circuits and alignment defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the shield electrode is disposed on the inner surface of the counter-substrate, then charging of the counter-substrate is suppressed, but the shield electrode is positioned close to the counter-electrode and pixel electrode causing alignment defect of liquid crystal molecules
Solution Approach 1:
The shield electrode is moved from the inner surface (first dimension - inside the cell) to the outer surface (second dimension - outside the cell) of the counter-substrate. This spatial relocation in another dimension maintains the charging suppression function while eliminating the harmful proximity to the liquid crystal layer, thus resolving the contradiction between reliability and manufacturing precision.
2Reliability
If the shield electrode is formed in a solid fashion on the outer surface of the mother-substrate, then charging suppression is achieved, but the shield electrode may be peeled off during cutting causing contamination by electrically conductive foreign matter
Solution Approach 1:
The shield electrode pattern is designed with segmented or discontinuous structures rather than solid continuous forms. This segmentation reduces the total peeled-off material during cutting while maintaining the electrostatic shielding function, thereby reducing contamination by electrically conductive foreign matter while preserving charging suppression capability.
Solution Approach 2:
The shield electrode is configured with varying properties in different regions - thicker or more robust in areas prone to peeling, and thinner or optimized in areas where shielding effectiveness is most critical. This local quality variation prevents peeling-induced contamination while maintaining charging suppression functionality.
3Ease of manufacture
If the area of injection port is contaminated, then electrically conductive foreign matter is drawn into the liquid crystal layer causing short-circuit between wiring lines or electrodes
Solution Approach 1:
The shield electrode configuration and cutting process are designed in advance to prevent peeling and contamination before the injection port area can be contaminated. By preemptively addressing the root cause (shield electrode peeling), the invention prevents subsequent contamination and short-circuit issues, maintaining both ease of manufacture and reliability.
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 design effectively suppresses counter-substrate charging, improves display quality, and increases manufacturing yield by preventing short-circuits and contamination, ensuring reliable operation and higher production efficiency.
Implementation Method 1
a shield electrode is disposed on the outer surface or inner surface of the counter-substrate
Implementation Method 2
liquid crystal molecules are switched by a transverse electric field that is produced between the pixel electrode and the counter-electrode
Data Source
AI summary
A liquid crystal display device includes an array substrate, a counter-substrate which is disposed to be opposed to the array substrate, a liquid crystal layer which is formed of a liquid crystal material which is held between the array substrate and the counter-substrate, and a sealant which bonds the array substrate and the counter-substrate. The array substrate includes a pixel electrode having a slit, and a counter-electrode which is opposed to the pixel electrode via an interlayer insulation film. The counter-substrate has a shield electrode on an outer surface thereof. The shield electrode is disposed such that an end portion thereof along at least one side of the counter-substrate, is exposed on the outer surface of the counter-substrate.