Liquid Crystal Display Color Layer Thickness Uniformity
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Solution Overview
Problem
The existing methods for producing liquid crystal display apparatuses face challenges in maintaining uniform cell gaps due to thickness differences caused by the overlap and positional shifts of exposure masks during the photolithography process, leading to potential decreases in display quality.
Innovation Solution
A method involving the use of specific exposure masks with mask patterns that transfer color layers to the color material layer in a way that minimizes mask joints, ensuring spacers are placed in regions with small thickness differences, thereby avoiding the adverse effects of mask joint-induced thickness variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If exposure masks are used with overlapping mask patterns to form color layers, then the color layer formation is achieved, but thickness differences are generated at mask joint regions
Solution Approach 1:
The patent applies local quality by making different regions of the mask pattern have different properties: the first mask pattern has openings with a first size while the second mask pattern has openings with a second size (different from the first size). This creates a gradient in opening sizes across the mask joint region, which compensates for the thickness difference generated by the overlapping mask patterns, thereby achieving uniform color layer thickness while maintaining the ease of manufacture through photolithography.
2Manufacturing precision
If spacers are placed in mask joint regions to maintain cell gap, then cell gap uniformity is attempted, but display quality decreases due to thickness differences
Solution Approach 1:
The patent applies preliminary action by pre-designing the mask patterns with different opening sizes before the photolithography process. The first mask pattern includes openings of a first size and the second mask pattern includes openings of a second size, creating a predetermined gradient that compensates for future thickness differences. This allows spacers to be placed in mask joint regions without compromising display quality, as the thickness difference is already compensated for by the different opening sizes.
3Ease of manufacture
If mask patterns are shifted to form color layers, then color layer patterning is achieved, but thickness variations are introduced
Solution Approach 1:
The patent applies parameter changes by varying the opening size parameter across different mask patterns. The first mask pattern uses openings of a first size while the second mask pattern uses openings of a second size. This parameter change creates a gradual transition in opening sizes at the mask joint, which compensates for the thickness variation introduced by the positional shift between masks, thereby achieving both ease of manufacture and thickness consistency.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach ensures uniform cell gaps and improves the display quality by strategically placing spacers in non-mask joint regions, reducing the impact of thickness differences and maintaining consistent pixel spacing.
Implementation Method 1
performing photolithography by use of a first exposure mask having a first mask pattern corresponding to a color layer of one color among the color layers, thereby transferring the first mask pattern to a first area of the color material layer
Data Source
AI summary
A method produces a liquid crystal display. The display includes a plurality of pixels having sub-pixels that include one opening and one color layer. Some of the sub-pixels having the same color are continuously spaced in one direction. In the method, overlapping photolithographic patterns produce mask openings in which a color layer in two spaced adjacent sub-pixels is to be formed. The mask openings each have a size corresponding to two or more adjacent sub-pixels; and the number of sub-pixels of the same color that are continuously arranged in the one direction is at least twice the total number of sub-pixels of the same color included in each of the pixels.