Color Film Substrate With Overlapping Black Matrices for High-PPI Displays
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Solution Overview
Problem
The challenge of BM remains in high PPI display panels due to small opening sizes during the development process, leading to defects like half-pixel dark spots and reduced product yield.
Innovation Solution
A color film substrate design involving a first black matrix and a second black matrix that partially overlap, forming a grid pattern with larger openings to facilitate easier removal of BM material during development, reducing the occurrence of BM remains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the opening size of the black matrix is reduced to increase PPI, then the pixel density is improved, but the BM material cannot be completely removed during development causing BM remains
Solution Approach 1:
The black matrix is divided into two separate layers: a first black matrix layer and a second black matrix layer. Each layer has its own opening pattern, and both layers are processed separately during development. This segmentation allows each layer to have larger individual opening sizes that can be properly developed, while the combined effect still achieves the desired high PPI shading performance.
Solution Approach 2:
The solution transitions from a single-layer black matrix design to a two-layer stacked design. By adding the vertical dimension (stacking two layers), the patent achieves both high PPI (through the combined small opening pattern) and complete BM removal (by having each individual layer with larger openings that can be properly developed).
2Measurement precision
If the opening size of the black matrix is reduced to increase PPI, then the pixel density is improved, but the development process becomes difficult causing BM remains
Solution Approach 1:
The development process is segmented into two separate steps: first developing the first black matrix layer, then developing the second black matrix layer. Each development step works with larger opening sizes that are easier to process, avoiding the difficulties of developing single small openings while still achieving the high PPI final structure.
Solution Approach 2:
The first black matrix layer is formed and developed first, establishing a preliminary structure with larger openings that are easy to process. Then the second black matrix layer is added and developed, building upon the first layer. This preliminary action allows each step to be performed under favorable conditions.
3Device complexity
If a single black matrix layer is used to achieve high PPI, then the structure is simple, but BM remains occur due to small opening sizes
Solution Approach 1:
The single black matrix layer is segmented into two separate layers, each with its own opening pattern. This segmentation eliminates BM remains by ensuring each layer has sufficiently large openings for complete development, thereby improving product yield and reliability while accepting increased structural complexity.
Solution Approach 2:
The patent uses a composite structure of two black matrix layers with different opening patterns. This composite approach combines the advantages of both layers to achieve complete BM removal and high PPI, improving reliability through the synergistic effect of the two-layer design.
Data Source
AI summary
Embodiments of the present disclosure provide a color film substrate and a method for preparing the same, and a display device. The color film substrate comprises a substrate; a first black matrix located on the substrate; and a second black matrix partially overlapping with the first black matrix, wherein at an overlapping position of the first black matrix and the second black matrix, the second black matrix overlays the first black matrix in a direction perpendicular to the substrate, and wherein a size of an opening defined by either of the first black matrix and the second black matrix is larger than a size of an opening defined by the first black matrix and the second black matrix together.