Liquid Crystal Display Black Matrix Spacer Alignment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Liquid crystal display devices face issues with display non-uniformity due to spacers, leading to variations in cell gap and alignment of liquid crystal molecules, which affect the contrast ratio and transmittance.
Innovation Solution
The placement of a columnar spacer at specific intersections of the black matrix's light-shield portions, along with a larger area for the black matrix below the spacer, helps in uniform alignment and reduces light leakage, while the color filter's single layer configuration stabilizes the spacer's shape and load distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a spacer is disposed between the array substrate and the counter-substrate to create a cell gap, then the cell gap is maintained, but display non-uniformity occurs due to spacer displacement and defective alignment areas
Solution Approach 1:
The black matrix is designed with different structures at different locations: a first light-shield portion with a specific structure and a second light-shield portion with a different structure. This local differentiation allows the black matrix to serve multiple functions: maintaining cell gap uniformity where needed while suppressing light leakage in specific areas, thereby resolving the contradiction between cell gap precision and display uniformity.
Solution Approach 2:
The black matrix is divided into multiple segments (first light-shield portion and second light-shield portion) with different configurations. The first light-shield portion has a structure that maintains cell gap, while the second light-shield portion has a structure that suppresses light leakage. This segmentation allows each part to optimize for its specific function, resolving the contradiction between maintaining cell gap uniformity and ensuring display uniformity.
2Object-generated harmful factors
If the black matrix area is increased to suppress light leakage, then light leakage is reduced, but the aperture ratio decreases affecting transmittance
Solution Approach 1:
The black matrix implements local quality by having different light-shield portions with different structures in different locations. The first light-shield portion is configured to suppress light leakage effectively, while the second light-shield portion is optimized to minimize impact on aperture ratio. This allows light leakage suppression without proportionally sacrificing transmittance.
Solution Approach 2:
The black matrix is segmented into multiple functional regions: the first light-shield portion that provides strong light shielding where needed, and the second light-shield portion that provides lighter shielding to preserve aperture ratio. This segmentation enables selective light leakage suppression without uniformly reducing the aperture ratio across the entire display area.
3Manufacturing precision
If the alignment treatment direction is parallel to the long side of the pixel electrode, then liquid crystal alignment is improved, but light leakage occurs in the defective alignment area
Solution Approach 1:
The patent converts the harmful effect of light leakage in defective alignment areas into a benefit by strategically positioning the second light-shield portion of the black matrix to cover these specific defective areas. The alignment treatment direction is optimized for overall liquid crystal alignment, while the black matrix's second light-shield portion compensates for the light leakage that occurs in the resulting defective areas, thus converting the harm into an acceptable solution.
Solution Approach 2:
The black matrix provides localized light shielding specifically in the defective alignment areas where light leakage occurs, while maintaining the overall alignment treatment direction parallel to the long side of the pixel electrode for optimal liquid crystal alignment. This local intervention suppresses light leakage without changing the global alignment configuration.
Data Source
AI summary
According to one embodiment, a liquid crystal display device includes a first substrate including a common electrode, an insulation film, and a pixel electrode, and a second substrate including a black matrix which includes a first light-shield portion, a second light-shield portion and a third light-shield portion, a first crossing portion at which the first light-shield portion and the second light-shield intersect, a second crossing portion at which the first light-shield portion and the third light-shield portion intersect, and a columnar spacer extending from a position overlapping the first crossing portion toward the first substrate.