IPS LCD Comb Tooth Electrode Bending for Dark Corner Mitigation
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Solution Overview
Problem
Liquid crystal display devices in IPS mode suffer from viewing angle characteristics issues, leading to luminance and chromaticity changes when viewed from different angles, resulting in dark unevenness due to ion migration and accumulation on the peripheral portions of the screen.
Innovation Solution
The implementation of a configuration with comb tooth pixel electrodes on both the display and dummy pixel regions, where the pixel electrodes are bent in opposite directions and the TFTs are positioned accordingly to counteract ion migration, preventing ion accumulation and maintaining evenness across the screen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a pixel electrode is bent in a dual domain mode to uniformize viewing angle characteristics, then viewing angle characteristics are improved, but ion migration causes dark unevenness on the corner portion of the display region
Solution Approach 1:
The invention divides the display region into multiple regions (first region, second region, third region, fourth region) with different pixel electrode bending directions. Each region has pixels with electrodes bent in specific directions (e.g., upper right, lower right, lower left, upper left) to distribute ion migration effects across different areas, preventing concentration of dark unevenness in any single corner.
Solution Approach 2:
Different regions of the display panel are assigned different pixel electrode configurations. The pixel electrode bending direction varies by region: first region (upper right bend), second region (lower right bend), third region (lower left bend), fourth region (upper left bend). This local differentiation ensures that ion migration affects different areas differently, balancing the overall display uniformity.
2Illumination intensity
If a pixel electrode is bent to improve viewing angle characteristics, then luminance uniformity is improved, but ion accumulation occurs on the peripheral portion causing dark corners
Solution Approach 1:
Instead of bending all pixel electrodes in the same direction to improve viewing angles, the invention inverts the bending direction in different regions. Adjacent regions have opposite bending directions (e.g., first region bends upper right, second region bends lower right), causing ions to migrate toward different peripheral areas. This inversion strategy distributes the harmful ion accumulation effect across all corners rather than concentrating it in one location.
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 effectively prevents dark unevenness by directing ion flow in opposite directions between the display and dummy pixel regions, ensuring consistent viewing angles and improved display quality.
Implementation Method 1
an IPS (In Plane Switching) mode has more excellent characteristics in which liquid crystal molecules are operated with a horizontal electric field
Implementation Method 2
ions in a liquid crystal are moved in the orientation of an arrow illustrated in FIG. 18, and dark unevenness 15 is produced on the upper right corner portion of a display region 10
Data Source
AI summary
In an IPS mode liquid crystal display device, measures are taken against dark unevenness at the corner portion of a screen. The problem can be solved by a liquid crystal display device in which a comb tooth pixel electrode is formed on a common electrode formed in a flat surface through an interlayer insulating film; a TFT substrate is formed with a dummy pixel region and a display region surrounding the display region; a pixel on the display region is formed with a comb tooth display region pixel electrode bent in a projection in the first direction; and a pixel on the dummy pixel region is formed with a comb tooth dummy pixel region pixel electrode bent in a projection in a direction opposite to the first direction at an angle of 180 degrees.