Liquid Crystal Display Cell Gap Control via Segmented Pillar Spacers
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Solution Overview
Problem
Liquid crystal display devices in OCB mode face challenges in maintaining accurate cell gap, which can lead to display unevenness due to impurity distribution and shifting cell gaps, especially in the shield area, affecting the active display area's cell gap and image quality.
Innovation Solution
The implementation of a liquid crystal display device structure with a first and second pillar-shaped spacer, supported by corresponding seat layers including shield and color filter layers, ensures a consistent cell gap in both the active and shield areas, using a multi-gap structure to optimize retardation and absorb impurities, thereby controlling display unevenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a pillar-shaped resin spacer is formed on the colored layer in the active region, then the cell gap can be maintained, but display unevenness occurs due to impurity distribution and shifting cell gaps in the shield area
Solution Approach 1:
The invention divides the spacer structure into two segments: a first pillar-shaped spacer in the active region and a second pillar-shaped spacer in the shield area. This segmentation allows independent optimization of each region's cell gap, preventing impurity distribution from affecting the active region and eliminating display unevenness while maintaining manufacturing precision.
Solution Approach 2:
The invention applies different spacer configurations to different regions: the first pillar-shaped spacer is positioned where liquid crystal molecules are densely distributed in the active region, while the second pillar-shaped spacer is positioned in the shield area. This local differentiation ensures that each region's specific requirements are met, maintaining cell gap accuracy and display uniformity simultaneously.
2Manufacturing precision
If the cell gap is controlled in the active area, then display quality is improved, but cell gap shifting in the shield area affects the active display area
Solution Approach 1:
The invention extracts the cell gap control function from the active region only and extends it to the shield area by adding a second pillar-shaped spacer. This extraction isolates the cell gap stability requirement to both regions independently, preventing harmful cell gap shifting from the shield area from affecting the active display area, thereby maintaining manufacturing precision throughout the entire device.
3Manufacturing precision
If a multi-gap structure is used to optimize retardation, then image quality is improved, but device complexity increases
Solution Approach 1:
The invention makes the second pillar-shaped spacer in the shield area serve multiple functions: it maintains cell gap accuracy in the shield area, prevents impurity distribution, and optimizes retardation for the active region through its multi-gap structure. This multi-functionality allows the spacer structure to achieve retardation optimization and image quality improvement without proportionally increasing device complexity.
Data Source
AI summary
In one embodiment, a liquid crystal display device includes a first substrate having a first pixel electrode and a first pillar-shaped spacer arranged in an active area, and a second pixel electrode and a second pillar-shaped spacer arranged in a shield area surrounding the active area. A shield layer is formed in the shape of a belt crossing above the first pillar-shaped spacer in the active area and extending to the shield area including a portion above the second pillar-shaped spacer. The height of a first seat layer formed above the first pillar-shaped spacer and including the shield layer, a first color filter layer and an overcoat layer is substantially the same as that of a second seat layer formed above the second pillar-shaped spacer and including the shield layer, a second color filter layer and the overcoat layer.