COT LCD White Pattern and Column Spacer Integration
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Solution Overview
Problem
The production cost and productivity of color filter on transistor (COT) type liquid crystal display devices are hindered by the high number of mask processes and the expense of black resin used for black column spacers in existing manufacturing methods.
Innovation Solution
The COT-type LCD design incorporates red, green, and blue color filters with a white pattern on a substrate, featuring a planarization layer and column spacers made of the same organic material, reducing the number of mask processes and using a less expensive material for the column spacers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If white color filter is added to increase transmittance, then transmittance is improved, but the number of mask processes increases and productivity decreases
Solution Approach 1:
The patent combines the white pattern formation and column spacer formation into a single mask process. The organic material is coated and patterned to simultaneously create both the white pattern in the white pixel region and the column spacer structure, eliminating the need for separate mask processes that would otherwise be required for each component.
Solution Approach 2:
The organic material serves multiple functions: it forms the white pattern that increases transmittance in white pixels, simultaneously forms the column spacer that maintains cell gap, and replaces the expensive black resin. This multi-functional approach allows a single material and process to achieve multiple objectives that traditionally required separate processes.
2Strength
If black resin is used for column spacer, then structural integrity is maintained, but production cost increases
Solution Approach 1:
The patent replaces expensive black resin with a cost-effective organic material for forming the column spacer. The organic material, which is already used for the white pattern, provides sufficient structural integrity to maintain the cell gap between substrates while significantly reducing material costs compared to traditional black resin.
Solution Approach 2:
The patent uses the same organic material for both the white pattern and the column spacer, creating homogeneity in material composition. This approach simplifies the manufacturing process by using a single material system and reduces costs by eliminating the need for expensive black resin, while the organic material maintains adequate mechanical properties for spacer functionality.
3Manufacturing precision
If multiple mask processes are used to form white pattern and column spacer separately, then manufacturing precision is improved, but production time increases
Solution Approach 1:
The patent merges the white pattern formation and column spacer formation into a single mask process. By coating the organic material over the entire substrate and then performing a single patterning step, both structures are created simultaneously, reducing the number of mask processes from multiple sequential steps to one integrated process.
Solution Approach 2:
The organic material is coated in advance over the entire substrate before patterning. This preliminary coating ensures that both the white pattern and column spacer regions are covered with the material, allowing a single subsequent patterning step to define both structures simultaneously, thereby reducing total process time.
Data Source
AI summary
Disclosed is a color filter on transistor (COT) type liquid crystal display device that may include red, green, blue and white pixels on a substrate; red, green and blue color filters in the red green and blue pixels, respectively, and a white pattern in the white pixel; a planarization layer on the red, green and blue color filters; and a column spacer on the planarization layer, wherein the column spacer and the white pattern are made of the substantially same material.