Color Filter Edge Overlap Exposure Control
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Solution Overview
Problem
The formation of color filters with overlapping portions in display devices leads to unevenness, which reduces contrast due to rubbing defects and necessitates the additional step of forming a leveling film, increasing the number of manufacturing steps.
Innovation Solution
A manufacturing method where color filters are patterned with varying exposure quantities at their edge portions to ensure physical contact and overlap, eliminating the need for a leveling film by making the overlapping surfaces flat without additional processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If color filters are formed with overlapping portions to eliminate the need for light blocking films, then the device complexity is reduced, but unevenness occurs at the overlapping portions causing rubbing defects and contrast reduction
Solution Approach 1:
The patent applies different exposure quantities to different regions of the color resist film. Specifically, the exposure quantity in the overlapping region is controlled to be different from the non-overlapping regions, creating local variations in the developed film thickness. This local quality control enables the overlapping portions to have flat surfaces while maintaining the overall overlapping structure, thus resolving the contradiction between simplified device structure and surface flatness.
2Manufacturing precision
If a leveling film is formed to cover the color filters and reduce unevenness, then the surface flatness is improved, but the number of manufacturing steps is increased
Solution Approach 1:
The patent performs the leveling action during the color filter formation process itself by controlling the exposure quantity in advance. By adjusting the exposure parameters before development, the color resist film is formed with the desired flat surface profile directly, eliminating the need for subsequent leveling films. This preliminary action integrates the leveling function into the existing manufacturing process, maintaining productivity while achieving surface flatness.
3Manufacturing precision
If exposure quantity is varied at edge portions of color filters during patterning, then unevenness at overlapping portions is reduced, but the manufacturing process complexity is increased
Solution Approach 1:
The patent changes the exposure parameter (exposure quantity) as a function of position on the color resist film. By varying the exposure quantity across different regions, particularly at the edge portions that form overlapping areas, the development process produces color filters with controlled surface profiles. This parameter change approach achieves flat overlapping surfaces through a single patterning step without adding complex multi-step processes, thus resolving the contradiction between manufacturing precision and process complexity.
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 method reduces unevenness at the overlapping portions of color filters, maintaining contrast and reducing the number of manufacturing steps by eliminating the need for a leveling film, thereby simplifying the process.
Implementation Method 1
a second exposure step in which a second color resist film is exposed after the second color resist film is applied
Data Source
AI summary
Disclosed is a manufacturing method of a liquid crystal display device where first color filters, second color filters and third color filters which are formed adjacent to each other are provided, the first color filter and the second color filter are patterned in such a manner that one edge portion of the second color filter overlaps an edge portion of the first color filter, and the second color filter and the third color filter are patterned in such a manner that an edge portion of the third color filter overlaps the other edge portion of the second color filter wherein in an exposure step for patterning the second color filter, an exposure quantity in a region corresponding to one edge portion and an exposure quantity in a region corresponding to the other edge portion differ from each other.