Color Filter Substrate Gray Scale Mask Reduces Horn Section
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Solution Overview
Problem
Traditional color filter substrates in TFT-LCD panels suffer from undulating topography due to serious color resist stacking, affecting liquid crystal performance and increasing material costs and production time.
Innovation Solution
A color filter substrate with a photo mask featuring a light shielding region and a semi-transparent gray scale mask area, where the shading pattern is disposed near the transmission region to form a semi-transparent gray scale mask area, allowing the color resist layer to thin gradually at the edges, reducing the horn section in overlapping regions and eliminating the need for an OC flat layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional RGB pixel photo mask with whole transmission area is used, then the color filter substrate can be manufactured, but serious color resist stacking occurs in overlapping areas causing undulating topography that affects liquid crystal performance
Solution Approach 1:
The photo mask introduces a gray scale mask area with different light transmission characteristics in specific regions (overlapping areas of color resist patterns). This creates local variation in color resist thickness, making the edge areas thinner to reduce stacking effects while maintaining uniform thickness in non-overlapping areas, thus resolving the topography issue without affecting overall manufacturing quality
Solution Approach 2:
The gray scale mask area is designed into the photo mask structure before the coloring process. This preliminary patterning prevents serious color resist stacking by controlling the exposure dose distribution, thereby preventing the formation of undulating topography before the color resist is even applied and developed
2Manufacturing precision
If OC flat layer is coated on RGB pixel filter film to reduce horn section, then the surface flatness is improved, but material cost increases and process period extends reducing productivity
Solution Approach 1:
The invention extracts and removes the OC flat layer from the manufacturing process by incorporating the flatness control function directly into the photo mask design. The gray scale mask area creates the necessary thickness variation during the coloring process itself, eliminating the need for the separate OC flat layer coating step, thus reducing material cost and process time while maintaining surface flatness
Solution Approach 2:
The flatness control function is merged with the coloring process by integrating the gray scale mask area into the photo mask. This combines two previously separate functions (coloring and flatness control) into a single process step, eliminating the need for the OC flat layer and improving productivity
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
The solution improves liquid crystal performance, reduces production costs, and simplifies the manufacturing process by maintaining a flat surface without the OC flat layer, enhancing productivity.
Implementation Method 1
exposing a color resist layer by a photo mask, wherein the photo mask comprises a light shielding region and a transmission region surrounded by the light shielding area, and a spaced shading pattern being disposed in an edge of the light shielding region near the transmission region to form a semi-transparent gray scale mask area; developing the color resist layer after exposing to obtain a color resist pattern
Data Source
AI summary
A color filter substrate used in a display and the method thereby, and the photo mask of the color filter substrate are disclosed. The color filter substrate comprises a main body and a plurality color resist patterns on the main body. The adjacent color resist patterns partially overlap wherein in the overlapping region, the thickness of bottom color resist pattern is gradually thinning in its edge direction. Through the above way, the horn section in the overlapping region of the adjacent RGB color resist patterns of the color filter substrate is reduced. The performance of the liquid crystals is improved. Moreover, the OC flat layer does not need to be built on RGB the color resist pattern. The production cost of the liquid crystal display device is reduced and the productivity is improved.