Pixel Electrode Segmentation for Display Brightness Uniformity
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Solution Overview
Problem
In display array substrates, particularly in VA, IPS, and FFS types, the uneven brightness distribution causes mura due to difficulties in controlling the line width of indium tin oxide (ITO) slits during exposure and etching, leading to unstable transmittance and segment differences between subpixels.
Innovation Solution
A pixel structure with subpixels divided into multiple compensation areas for the first, second, third, and fourth subpixel electrodes, where each electrode is divided into inner-layer, intermediate-layer, and outer-layer components, with line widths adjusted to 80% to 120% of the primary subpixel electrodes, and various geometric forms like rectangles, circles, or rhombuses are used to correct electrode line widths and mitigate brightness differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pixel electrode is designed with a slit form to control line width, then liquid crystal efficiency is improved, but manufacturing precision deteriorates due to severe segment difference and difficulty in controlling ITO slit line width during exposure and etching
Solution Approach 1:
The fourth subpixel electrode is divided into four separate pixel electrodes (first, second, third, and fourth pixel electrodes) positioned in four different areas. Each pixel electrode is further divided into multiple compensation areas with different line widths. This segmentation allows independent optimization of each region to compensate for manufacturing variations and maintain consistent liquid crystal efficiency across the entire subpixel.
Solution Approach 2:
Different compensation areas within each pixel electrode are assigned different line widths (ranging from 80% to 120% of the reference line width) based on their specific location and manufacturing variation characteristics. This local quality adjustment ensures that each region has the optimal line width for its specific conditions, thereby compensating for segment differences and maintaining uniform liquid crystal efficiency.
2Reliability
If the ITO slit line width is controlled during exposure and etching, then transmittance stability is improved, but device complexity increases due to the need for precise process control
Solution Approach 1:
The pixel electrode pattern is designed in advance with compensation areas having predetermined different line widths (80%, 90%, 100%, 110%, 120% of reference width) before manufacturing. This preliminary design incorporates the compensation strategy into the electrode structure itself, eliminating the need for complex real-time process control during exposure and etching, while still achieving transmittance stability.
3Illumination intensity
If compensation areas with different line widths are used to correct electrode variations, then brightness difference is reduced, but device complexity increases due to multiple electrode components
Solution Approach 1:
The four pixel electrodes and their multiple compensation areas are merged into a single continuous fourth subpixel electrode structure. This unified structure maintains the functional benefits of different line widths for brightness uniformity while simplifying the overall device architecture by eliminating the need for separate electrode components and reducing fabrication steps.
Data Source
AI summary
This application provides a pixel structure of display array substrate and a display device applied thereto. The pixel structure of display array substrate includes a plurality of pixel units arranged in an array manner. Each pixel unit includes a first subpixel, a second subpixel, and a fourth subpixel. Each pixel unit further includes: a first subpixel electrode and a second subpixel electrode, respectively located in the first subpixel and the second subpixel; and a fourth subpixel electrode, where the fourth subpixel electrode includes a first pixel electrode, a second pixel electrode, a third pixel electrode, and a fourth pixel electrode located in four areas of the fourth subpixel, respectively, and each the first pixel electrode, the second pixel electrode, the third pixel electrode, and the fourth pixel electrode are divided into at least two compensation area.