Display Device Spacer Configuration for Uniform Cell Gap
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Solution Overview
Problem
Liquid crystal display devices experience non-uniform cell gaps due to differences in spacer heights between the edge and inner areas, leading to the edge stain phenomenon where the edge area appears brighter than the inner area, affecting display quality.
Innovation Solution
The implementation of a display device design with main and sub column spacers, where the main spacers are only in the inner area and the sub spacers are in both the inner and edge areas, maintaining uniform spacing between substrates and adjusting the light blocking pattern thickness to prevent non-uniform cell gaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If column spacers are formed using conventional methods, then the display area can be manufactured, but non-uniform cell gaps occur between edge and inner areas leading to edge stain phenomenon
Solution Approach 1:
The display area is divided into an inner area and an edge area, with different spacer configurations for each region. Main column spacers are placed only in the inner area, while sub column spacers are placed in both the inner and edge areas, creating region-specific solutions to achieve uniform cell gaps across the entire display area.
Solution Approach 2:
Different types of spacers with different heights are used in different regions of the display area. The sub column spacers in the edge area have a first height, while the main column spacers in the inner area have a second height different from the first height, allowing local optimization of cell gap uniformity in each region.
2Ease of manufacture
If spacers of uniform height are used across the entire display area, then manufacturing is simplified, but non-uniform cell gaps occur in the edge area adjacent to the non-display area
Solution Approach 1:
The spacer system is segmented into two distinct types: sub column spacers for the edge area and main column spacers for the inner area. This segmentation allows each spacer type to be optimized for its specific region, with sub column spacers preventing edge stain and main column spacers maintaining appropriate cell gap in the inner area.
Solution Approach 2:
The invention applies the local quality principle by using spacers with different heights in different regions. Sub column spacers with a first height are used in the edge area to compensate for the thickness difference, while main column spacers with a second height are used in the inner area, achieving local optimization of cell gap uniformity.
3Manufacturing precision
If the cell gap is reduced in the edge area to match the inner area, then uniform liquid crystal filling is achieved, but the thickness difference between display and non-display areas causes spacer height mismatch
Solution Approach 1:
The invention resolves the height mismatch by applying local quality: sub column spacers in the edge area have a first height that accommodates the reduced cell gap, while main column spacers in the inner area have a second height for the normal cell gap. This region-specific spacer height design allows uniform liquid crystal filling while maintaining spacer shape consistency within each region.
Data Source
AI summary
A display device includes a first substrate, thin film transistors, a color filter layer, a light blocking pattern, a second substrate, pixel electrodes, and, a plurality of first spacers. The first substrate includes a display area having a plurality of pixel areas and a non-display area surrounding at least part of the display area, the display area including an interior area and at least one peripheral area disposed exteriorly of the interior area. The second substrate defines with the first substrate a space to contain light transmittance material. The plurality of first spacers is disposed in the light transmittance space between the first and second substrates and only in the interior area of the display area.