Display Substrate Electrode Layout for TN Bright Spot Suppression
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Solution Overview
Problem
TN-type display devices experience local bright spots due to lateral flow and squeezing of liquid crystal molecules, particularly at positions with small lateral dimensions, leading to microscopic bright blue lines when the display panel is pressed.
Innovation Solution
The display substrate design includes specific configurations for the common and pixel electrodes, with a protrusion on the common electrode increasing the area and capacitance of sub-pixel structures, and the use of a half via-hole structure and black matrix to adjust liquid crystal flow and prevent bright spots by increasing the minimum distance between electrode portions and providing additional lateral flow space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the display panel is pressed, then the liquid crystal molecules are squeezed and lateral flow occurs, but this leads to optical rotation anomalies and local bright spots
Solution Approach 1:
The patent applies local quality by creating asymmetric electrode configurations specifically targeted at the target sub-pixel structure. The common electrode includes a first portion, second portion, third portion, and fourth portion with specific spatial relationships, while the pixel electrode has corresponding asymmetric portions. This localized asymmetric structure is designed to counteract the lateral flow and squeezing effects of liquid crystal molecules in specific regions, thereby preventing bright spots without affecting other areas of the display panel.
Solution Approach 2:
The patent implements asymmetry through the non-symmetric arrangement of electrode portions. The first portion and second portion of the common electrode are arranged along a first direction and extend along a second direction, with the fourth portion coupled to the first portion at a specific side. This asymmetric electrode configuration creates non-uniform electric fields that compensate for the asymmetric lateral flow of liquid crystal molecules under pressure, preventing optical rotation anomalies and bright spot formation.
2Reliability
If the common electrode and pixel electrode are configured with multiple portions, then the lateral flow space for liquid crystals is increased, but the device structure becomes more complex
Solution Approach 1:
The patent applies segmentation by dividing both the common electrode and pixel electrode into multiple distinct portions. The common electrode is segmented into a first portion, second portion, third portion, and fourth portion, while the pixel electrode is segmented into corresponding first portion, second portion, third portion, and fourth portion. Each segment serves a specific function in managing liquid crystal flow patterns, allowing precise control over lateral flow without requiring complete structural redesign of the entire electrode system.
Solution Approach 2:
The patent applies local quality by creating asymmetric electrode configurations specifically targeted at the target sub-pixel structure. The common electrode includes a first portion, second portion, third portion, and fourth portion with specific spatial relationships, while the pixel electrode has corresponding asymmetric portions. This localized asymmetric structure is designed to counteract the lateral flow and squeezing effects of liquid crystal molecules in specific regions, thereby preventing bright spots without affecting other areas of the display panel.
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
Prevents the occurrence of bright spots by ensuring sufficient space for liquid crystal molecules, maintaining display quality and capacitance, and optimizing the display panel's structure to reduce the likelihood of molecular squeezing.
Implementation Method 1
nematic liquid crystals form a 90° twisted alignment structure in a display screen
Implementation Method 2
the twisted structure disappears, and an optical rotation phenomenon disappears too
Implementation Method 3
liquid crystal molecules return to be arranged in the original twisted manner under the effect of an anchoring force generated at a surface of an alignment film
Implementation Method 4
Through controlling a magnitude of the applied voltage, it is able to control a twist degree of the TN liquid crystal molecules, thereby to control the brightness of light transmitted through the liquid crystals
Data Source
AI summary
The present disclosure provides a display substrate and a display device. The display substrate includes a first substrate, and scanning lines and data lines arranged on the first substrate. The display substrate includes a plurality of pixel structures, each pixel structure includes a plurality of sub-pixel structures, each sub-pixel structure includes a common electrode and a pixel electrode, and an orthogonal projection of the common electrode onto the first substrate overlaps with an orthogonal projection of the pixel electrode onto the first substrate. The sub-pixel structures include a target sub-pixel structure, the common electrode of the target sub-pixel structure includes a first portion, a second portion, a third portion, and a fourth portion, and the first portion and the second portion are arranged along a first direction and extend along a second direction.