LCD Spacer Area Ratios for Uniform Alignment Film Coating
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Solution Overview
Problem
In liquid crystal display devices, the uneven coating of alignment film material due to the larger area of pedestal portions compared to spacers leads to display failures, especially when sub-spacers are densely arranged, causing coating unevenness and making it difficult to form alignment films uniformly.
Innovation Solution
A liquid crystal display device configuration with a main spacer and sub-spacer on one substrate, and a main pedestal portion and sub-pedestal portion on the opposing substrate, where the area of the main pedestal portion is greater than the main spacer and the sub-pedestal portion is smaller than the sub-spacer, with a higher arrangement density of sub-pedestal portions, to ensure proper alignment and prevent excessive deformation under pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the area of pedestal portions is made larger than spacers to ensure proper alignment and load resistance, then the load-resistant properties are improved, but the alignment film coating becomes uneven leading to display failures
Solution Approach 1:
The invention applies different area ratios to different types of spacers and pedestal portions. Specifically, the main spacer has a larger area relative to its pedestal portion compared to sub-spacers. This local differentiation allows the main spacer to provide sufficient alignment tolerance while sub-spacers maintain smaller areas that minimize coating interference, thus resolving the contradiction between load resistance and coating uniformity.
Solution Approach 2:
The invention segments the spacer system into two distinct categories: main spacers with larger area ratios (0.5-2.0 times the pedestal portion area) and sub-spacers with smaller area ratios (0.1-0.5 times the pedestal portion area). This segmentation allows different functional requirements to be met simultaneously - main spacers handle alignment and primary load bearing, while sub-spacers provide secondary support with minimal coating interference.
2Strength
If a large number of sub-spacers are disposed to ensure strength, then the load-resistant properties are improved, but the spacing between adjacent pedestal portions is decreased causing coating unevenness
Solution Approach 1:
The invention applies different area ratios to different types of spacers and pedestal portions. Specifically, the main spacer has a larger area relative to its pedestal portion compared to sub-spacers. This local differentiation allows the main spacer to provide sufficient alignment tolerance while sub-spacers maintain smaller areas that minimize coating interference, thus resolving the contradiction between load resistance and coating uniformity.
Solution Approach 2:
The invention segments the spacer system into two distinct categories: main spacers with larger area ratios (0.5-2.0 times the pedestal portion area) and sub-spacers with smaller area ratios (0.1-0.5 times the pedestal portion area). This segmentation allows different functional requirements to be met simultaneously - main spacers handle alignment and primary load bearing, while sub-spacers provide secondary support with minimal coating interference.
Data Source
AI summary
A liquid crystal display device includes a first substrate, a second substrate, and a liquid crystal layer supported between the first substrate and the second substrate, wherein the first substrate includes a main spacer and a sub-spacer protruding toward the liquid crystal layer, a height of the main spacer is greater than a height of the sub-spacer, the second substrate includes, on a surface facing the liquid crystal layer, an alignment film, a main pedestal portion that comes into contact with the main spacer, and a sub-pedestal portion opposite the sub-spacer, an area of a top portion of the main pedestal portion is greater than an area of a top portion of the main spacer, and an area of a top portion of the sub-pedestal portion is less than an area of a top portion of the sub-spacer.