Bead Spacer Configuration for LCD Cell Gap Control
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Solution Overview
Problem
In liquid crystal displays (LCDs), bead spacers can cause light leakage and damage to the alignment layer due to their irregular distribution and movement, leading to defective alignment and increased manufacturing time and cost, as they can act as foreign particles and contaminate the liquid crystal material during assembly.
Innovation Solution
The use of two groups of bead spacers with different sizes and elasticity coefficients, where the first group is smaller and less elastic, and the second group is larger and more elastic, are strategically placed to maintain a constant cell gap and control the liquid crystal material's velocity, preventing it from contacting the unhardened sealant and ensuring uniform distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If bead spacers are spread irregularly before combining display panels, then the assembly process is simple, but the bead spacers may move and damage the alignment layer, causing defective alignment
Solution Approach 1:
The patent applies preliminary action by forming a dam structure on the first display panel before spreading the bead spacers. This dam is created in advance to prevent liquid crystal material from contacting the unhardened sealant, thereby solving the alignment problem before the assembly process begins while maintaining the simplicity of spreading bead spacers
2Reliability
If a dam is formed to prevent liquid crystal material from contacting unhardened sealant, then contamination is prevented, but the dam may have non-uniform height allowing liquid crystal to move through low portions
Solution Approach 1:
The patent applies parameter changes by varying the height of the dam structure at different locations. The dam has a first height at the circumferential edge and a second height at the display area, with the first height being greater than the second height. This gradient structure prevents liquid crystal from overflowing while maintaining effective containment throughout the assembly process
3Reliability
If additional processes are added to manufacture the dam uniformly, then contamination prevention is improved, but manufacturing time and cost increase
Solution Approach 1:
The patent merges the dam formation process with the existing display panel manufacturing process. The dam is formed as part of the color filter array panel fabrication using the same coating and patterning steps, eliminating the need for separate dam manufacturing processes and maintaining high production efficiency while ensuring uniform and reliable contamination prevention
4Length of stationary object
If bead spacers are used to maintain cell gap, then the cell gap is sustained, but the irregular distribution causes light leakage and deteriorates contrast ratio
Solution Approach 1:
The patent applies local quality by positioning bead spacers specifically within the display area rather than distributing them uniformly across the entire panel. The bead spacers are arranged in regions corresponding to pixel structures, providing localized cell gap maintenance where needed while avoiding light leakage in the peripheral areas, thereby improving contrast ratio
Data Source
AI summary
A liquid crystal display includes a first substrate having a display area and a peripheral area and including a plurality of pixels formed in the display area, a second substrate facing the first substrate, and a plurality of first groups of bead spacers and a plurality of second groups of bead spacers disposed between the first substrate and the second substrate. The first groups of bead spacers have a different size or different elasticity coefficient than the second groups of bead spacers, and include a plurality of bead spacers, respectively.