Display Substrate Black Matrix Alignment for LCD
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Solution Overview
Problem
Aligning errors between the array substrate and the color filter substrate in liquid crystal display (LCD) panels lead to color mixing and reduced transmittance due to misalignment of pixel electrodes and black matrices, resulting in undesirable display effects.
Innovation Solution
A display substrate with gate lines and data lines arranged in a crisscrossed pattern, including pixel units with thin film transistors and pixel electrodes, a color filter layer with specific color regions, and a black matrix that completely covers the gate lines, data lines, and thin film transistors, ensuring precise alignment and optimal light transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the array substrate and color filter substrate are assembled separately, then the manufacturing process is simplified, but aligning errors occur between pixel electrodes and color filter layer causing color mixing
Solution Approach 1:
The patent combines the color filter layer and black matrix into a single integrated color filter substrate structure. The color filter layer and black matrix are formed on the same substrate with precise spatial relationships established during manufacturing, eliminating the need for separate alignment operations and preventing color mixing while maintaining manufacturing simplicity
Solution Approach 2:
The patent introduces a common substrate as an intermediary platform that integrates both the color filter layer and black matrix. This common reference frame serves as a mediator that ensures precise relative positioning between the color filter regions and black matrix regions, eliminating aligning errors that would occur with separate substrates
2Illumination intensity
If the black matrix does not completely cover the gate lines and data lines, then the transmittance is improved, but light leakage occurs reducing display quality
Solution Approach 1:
The patent applies local quality by making the black matrix selectively opaque only in regions where gate lines and data lines are located, while maintaining transparency in pixel electrode regions. The black matrix is designed with spatially varying properties: opaque over conductive lines to prevent light leakage, and transparent over pixel areas to maximize light transmittance
3Manufacturing precision
If the pixel electrode faces multiple color regions, then the manufacturing tolerance is relaxed, but color mixing occurs causing poor display
Solution Approach 1:
The patent segments the color filter layer into distinct color regions (red, green, blue) that are spatially separated and each corresponds to a specific pixel electrode. The black matrix further segments the substrate by creating opaque boundaries between regions. This segmentation ensures that light passing through each pixel electrode encounters only its designated color region, preventing color mixing while maintaining clear manufacturing boundaries
Data Source
AI summary
Disclosed is a display substrate, including: a substrate; gate lines and data lines arranged in a crisscrossed pattern on the substrate; pixel units surrounded by the gate lines and the data lines, each of which includes a thin film transistor and a pixel electrode; a color filter layer disposed on the substrate and including at least one color region, a vertical projection of the pixel electrode within one of the pixel units on the substrate being within a vertical projection of one color region of the color filter layer on the substrate; and a black matrix disposed over the gate lines, the data lines and the thin film transistors, a vertical projection of all of the gate lines, the data lines and the thin film transistors on the substrate being within a vertical projection of the black matrix on the substrate.