Display Substrate Flat Surface via Reverse-Tapered Edge Overlap
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Solution Overview
Problem
The photolithography process for flat-panel display substrates is time-consuming and costly, and it often results in step differences in elevation between the light blocking layer and color filters, requiring an additional overcoat layer to achieve a flat surface.
Innovation Solution
A display substrate with a base substrate having pixel areas, light blocking layer patterns, and color filter patterns where the upper surfaces collectively form a flat surface, with reverse-tapered edge portions that overlap, eliminating the need for an exposure process and simplifying the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photolithography process is used to apply organic material to light blocking layer and color filters, then manufacturing precision is improved, but manufacturing time and cost increase
Solution Approach 1:
The patent extracts the exposure and development steps from the traditional photolithography process. Instead of using photosensitive organic materials that require multi-step photolithography processing, the invention uses non-photosensitive organic materials that can be directly coated and patterned, eliminating time-consuming exposure and development processes while maintaining precise material application
Solution Approach 2:
The patent employs a simple coating process instead of expensive photolithography equipment and materials. By using non-photosensitive organic materials that don't require complex processing, the invention reduces manufacturing cost and time while achieving the desired precision in organic material application
2Manufacturing precision
If photolithography process is used to apply organic material to light blocking layer and color filters, then manufacturing precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent removes the expensive exposure and development steps from the manufacturing process. By using non-photosensitive organic materials that can be directly coated and patterned without complex photolithography equipment, the invention significantly reduces manufacturing cost while maintaining the precision needed for organic material application
Solution Approach 2:
The invention replaces expensive photolithography processes with simple coating methods using non-photosensitive materials. This substitution eliminates the need for costly exposure equipment, photoresists, and multi-step processing, thereby reducing manufacturing cost while achieving adequate precision
3Manufacturing precision
If organic material is applied to color filters and light blocking layer, then color filter formation is improved, but step difference in elevation occurs requiring additional overcoat layer
Solution Approach 1:
The patent applies different thicknesses of non-photosensitive organic material to different regions. The organic material is coated to a greater thickness in the light blocking layer region compared to the color filter region, which compensates for the height difference and creates a substantially flat overall surface without requiring additional overcoat layers
Solution Approach 2:
The patent performs preliminary thickness adjustment during the coating process itself. By controlling the coating parameters and using appropriate coating methods, the desired thickness distribution is achieved directly during the initial coating step, preventing step differences before they occur and eliminating the need for subsequent overcoat processes
Data Source
AI summary
A display panel includes a base substrate having a plurality of pixel areas, in which each pixel area includes a plurality of sub-pixel areas, a light blocking layer pattern generally defining the sub-pixel areas, and a plurality of color filter patterns. Upper surfaces of the light blocking layer pattern and the plurality of color filter patterns collectively form a generally flat surface.