Multilayer Color Filter Spacers for LCD Height Control
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Solution Overview
Problem
Conventional liquid crystal display devices face challenges in maintaining optimal spacing between TFT and facing substrates, leading to reduced contrast and increased liquid crystal usage, which affects cost and reliability due to the difficulty in controlling spacer height and thermal stress.
Innovation Solution
The use of multilayer spacers formed from color filters, where the height is finely controlled by varying the area or layering order of color filters, allowing for different spacer heights and reducing liquid crystal usage by placing them between non-image-contributing pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multilayer spacers are formed using conventional photolithographic processes, then spacer height can be controlled, but manufacturing complexity and cost increase
Solution Approach 1:
The invention merges the spacer formation process with the existing color filter formation process. By forming spacers and color filters simultaneously in the same photolithographic steps using the same photoresist patterns, the patent eliminates separate spacer formation processes, reducing manufacturing complexity while maintaining precise spacer height control through the multilayer color filter structure.
Solution Approach 2:
The color filter layers serve dual functions: they provide the necessary color filtering function and simultaneously form the spacer structure. This multi-functionality eliminates the need for dedicated spacer materials and separate formation processes, reducing device complexity while maintaining manufacturing precision through the inherent structural control of the color filter layers.
2Ease of manufacture
If uniform spacer height is used throughout the display panel, then manufacturing is simplified, but optimal spacing cannot be achieved in different regions
Solution Approach 1:
The invention implements local quality by forming color filter layers with different thicknesses in different regions of the display panel. The first color filter layer has a first thickness in a first region and a second thickness in a second region, allowing each region to have the optimal spacer height for its specific requirements while using the same manufacturing process.
Solution Approach 2:
The spacer height is made dynamic and adaptable to different regions through the multilayer color filter structure. By controlling the thickness of individual color filter layers in different regions, the system can optimize the spacer height locally without changing the overall manufacturing process, achieving both ease of manufacture and manufacturing precision.
3Length of stationary object
If beads are dispersed to create space between substrates, then space definition is achieved, but light scattering occurs and contrast decreases
Solution Approach 1:
The invention extracts the spacer function from discrete bead particles and integrates it into the continuous color filter layer structure. By forming spacers as part of the color filter layers rather than using separate dispersed beads, the patent eliminates light scattering issues while maintaining the necessary space between substrates, thus preserving contrast and illumination quality.
4Ease of manufacture
If liquid crystal is dropped to fill the space, then filling is simplified, but bead movement creates non-uniform spacing
Solution Approach 1:
The invention performs preliminary action by forming the spacer structure (through multilayer color filter formation) before the liquid crystal filling process. The spacers are pre-positioned and fixed as part of the color filter layers, preventing any movement during liquid crystal dropping, thus maintaining space uniformity while allowing simplified liquid crystal filling.
5Reliability
If more liquid crystal is used to ensure proper filling, then filling reliability improves, but thermal stress increases
Solution Approach 1:
The invention uses the color filter layer pattern as a template or copy to define spacer positions and heights. By replicating the color filter structure to form spacers, the system ensures proper spacing and filling without requiring excess liquid crystal, thus maintaining filling reliability while reducing thermal stress from overfilling.
Data Source
AI summary
A liquid crystal display device includes a TFT substrate, a facing substrate and liquid crystal sandwiched therebetween. First pixels for displaying a first color according to a first color filter, second pixels for displaying a second color according a second color filter and third pixels for displaying a third color according to a third color filter are aligned in a longitudinal direction on the facing substrate, respectively. The first color filters, the second color filters, and the third color filters extend in stripes in the longitudinal direction so as to cover the first, second and third pixels, respectively. First spacers are formed between the first pixels by layering a number of color filters, including the first color filters, and second spacers are formed of a number of color filters, including the second color filters, between the second pixels. The first color filters which are formed between the second pixels are circular in plan view.