Blocking Structure for Alignment Mark in Display Substrate
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Solution Overview
Problem
The formation of zigzag residues at the edge of alignment marks on display substrates due to residual particles during the rubbing process leads to inaccurate cell alignment in TFT-LCDs, resulting in defects such as Mura and Zara defects.
Innovation Solution
A blocking structure is introduced around the alignment mark on the display substrate to prevent residual particles from being stacked, ensuring accurate alignment by blocking these particles during the rubbing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If rubbing process is performed on display substrate, then alignment mark profile is formed, but residual particles stack on alignment mark causing zigzag residues
Solution Approach 1:
A blocking structure is introduced as an intermediary element between the rubbing roller and the alignment mark. This blocking structure intercepts residual particles carried by the rubbing roller, preventing them from stacking on the alignment mark. The blocking structure serves as a mediator that sacrifices itself to protect the alignment mark from contamination, thereby resolving the contradiction between achieving alignment mark profile through rubbing and preventing residual particle contamination.
2Measurement precision
If alignment mark is used for cell alignment, then cell alignment accuracy is achieved, but zigzag residues cause alignment blur and offset
Solution Approach 1:
The blocking structure converts the harmful effect of residual particles into a beneficial outcome. By intentionally placing the blocking structure near the alignment mark, residual particles that would otherwise cause zigzag residues are redirected to stack on the blocking structure instead. This transforms the harmful contamination into a controlled feature that protects the alignment mark's integrity, ensuring accurate alignment mark identification and reliable cell alignment.
3Manufacturing precision
If blocking structure is added around alignment mark, then alignment accuracy is improved, but device complexity increases
Solution Approach 1:
The blocking structure is implemented with local quality by positioning it specifically in the preset region around the alignment mark where residual particles tend to stack, rather than uniformly across the entire substrate. The blocking structure's shape and position are optimized locally to intercept particles without interfering with the alignment mark's function or requiring complex modifications to the overall substrate design, thus improving alignment accuracy while minimizing device complexity.
Data Source
AI summary
A display substrate and a display device including the display substrate are provided. The display substrate includes an alignment mark in an alignment region of the display substrate; and a blocking structure in a preset region around the alignment mark, wherein the blocking structure is arranged to block residual particles carried by a rubbing roller during rubbing.