Liquid Crystal Panel Pixel Electrode Design for Brightness Uniformity
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Solution Overview
Problem
Thin Film Transistor-Liquid Crystal Displays (TFT-LCDs) suffer from a 'two pale lateral areas' issue due to distorted scanning driving voltage, resulting in lower brightness at the edges compared to the center, especially at low grayscale values.
Innovation Solution
The design of the liquid crystal panel includes pixel cells with strip-like gaps and electrode patterns that gradually decrease in width and increase in size from the center to the edges, maintaining a constant sum, which connects to scanning and data lines, and features a specific arrangement of electrode areas to optimize light transmission and reduce brightness differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If scanning driving voltage is inputted from two lateral sides of the liquid crystal panel, then the central area can be driven, but the scanning voltage becomes distorted due to RC delay, resulting in lower brightness at the central area compared to lateral areas
Solution Approach 1:
The patent applies local quality by making the pixel electrode patterns asymmetric: the sum of dimensions of first electrode patterns is gradually decreased from central area toward lateral areas, while the sum of dimensions of second electrode patterns is gradually increased from central area toward lateral areas. This local variation in electrode configuration compensates for the RC delay effect, ensuring uniform brightness across the display panel.
Solution Approach 2:
The patent changes the physical parameters of the pixel electrode patterns by adjusting the sum of dimensions of first and second electrode patterns in different regions. Specifically, the width and length of electrode patterns are varied across the panel to compensate for voltage distortion, transforming the uniform electrode design into a non-uniform design that accounts for spatial variations in electrical characteristics.
2Illumination intensity
If the sum of dimension of first electrode patterns is decreased from central area toward lateral areas, then brightness uniformity is improved, but the electrode pattern complexity increases
Solution Approach 1:
The patent divides the display panel into different regions (central area and lateral areas) and applies different electrode pattern configurations to each region. The first electrode patterns have gradually decreased sum of dimensions from center to edges, while second electrode patterns have gradually increased sum of dimensions, creating locally optimized patterns for each region to achieve overall brightness uniformity.
Solution Approach 2:
The patent introduces asymmetry in the pixel electrode design by using two sets of electrode patterns (first and second) with different dimensional characteristics. The first electrode patterns are configured with decreasing sum of dimensions from center to lateral areas, while second electrode patterns have increasing sum of dimensions, creating an asymmetric overall structure that compensates for the symmetric RC delay problem.
Data Source
AI summary
A liquid crystal panel and the array substrate thereof are disclosed. Each pixel cells of the liquid crystal panel includes one pixel electrode having a plurality of strip-like gaps and a plurality of strip-like first electrode patterns interleaved with each other. For all of the pixel cells, a sum of the dimension of the first electrode patterns of the pixel cell is gradually decreased along a direction from a central area toward two lateral areas of the liquid crystal panel. In this way, the brightness of the liquid crystal panel is uniform and the “two pale lateral areas” issue may be eased or eliminated.