Monochromatic Filter Layer Overlap for COE Black Matrix Elimination
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Solution Overview
Problem
Current Color Filter on Encapsulation (COE) structures face issues such as black matrix (BM) peeling, BM remain, and difficulty in BM exposure alignment during the manufacturing process, leading to problems like color shift at large viewing angles due to inconsistent luminance decay angles of red, green, and blue light.
Innovation Solution
A display substrate design featuring a color filter layer with sub-color filters and a monochromatic filter layer, where the monochromatic filter layer overlaps with the sub-color filters, forming a light-shielding region that reduces BM size and increases color filter thickness, thereby mitigating BM peeling and color shift issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a black matrix layer is used in the COE structure to replace the polarizer, then the anti-reflection function and flexibility are improved, but manufacturing problems occur including BM peeling, BM remain, and difficulty in BM exposure alignment
Solution Approach 1:
The patent extracts and removes the black matrix layer from the COE structure entirely. Instead of using BM to define pixel regions, the invention uses the color filter layers themselves (with transparent regions between them) to serve the light-shielding function, thereby eliminating the manufacturing problems associated with BM while maintaining the anti-reflection and flexibility benefits
Solution Approach 2:
The patent merges the functions of the black matrix layer and the color filter layers. The color filter layers are extended to overlap with each other in the thickness direction, creating overlapping regions that serve as the light-shielding regions previously provided by BM, thereby combining the light-shielding function with the color filtering function
2Productivity
If the black matrix layer is patterned using semiconductor processes, then the COE structure can be manufactured, but problems such as BM peeling and BM remain occur
Solution Approach 1:
The patent removes the black matrix layer entirely from the structure, eliminating the adhesion problems associated with BM patterning. The light-shielding function is achieved through the overlapping color filter layers instead, which are formed using the same semiconductor processes but without the peeling and remain issues
Solution Approach 2:
The patent creates a composite structure where multiple color filter layers overlap in the thickness direction. This composite arrangement of RGB color filter layers creates effective light-shielding regions without requiring a separate BM layer, thereby maintaining manufacturing capability while improving adhesion reliability
3Manufacturing precision
If the black matrix layer is used to define pixel regions, then the color filter layers can be patterned, but the luminance decay angles of red, green, and blue light become inconsistent, causing color shift at large viewing angles
Solution Approach 1:
The patent transitions from defining pixel regions in the planar direction using BM to defining them through overlapping regions in the thickness direction. The color filter layers overlap with each other vertically, and this overlapping arrangement in the thickness dimension creates the light-shielding effect while maintaining consistent luminance decay angles across different colors, thereby eliminating color shift at large viewing angles
Solution Approach 2:
The patent applies different transparency characteristics to different regions of the color filter layers. The overlapping regions have effective light-shielding properties (equivalent to BM), while the non-overlapping regions maintain color transmission. This local differentiation of quality within the color filter layers achieves both precise pixel region definition and consistent color performance
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 effectively reduces BM peeling and reflectivity, improves adhesion, and minimizes color shift at large viewing angles by increasing the color filter thickness and reducing BM size, enhancing the display effect and energy efficiency.
Implementation Method 1
the monochromatic filter layer is formed as a filter layer with a fourth primary color
Implementation Method 2
forming a light-shielding region that reduces BM size and increases color filter thickness
Data Source
AI summary
The present disclosure provides a display substrate, a method of manufacturing a display substrate, and a display device. The display substrate includes: a base substrate; a color filter layer arranged on the base substrate, wherein the color filter layer includes a plurality of sub-color filters; and a monochromatic filter layer arranged on a side of the color filter layer away from the base substrate, wherein the monochromatic filter layer is formed as a filter layer with a fourth primary color, one of the first primary color, the second primary color and the third primary color is the same as the fourth primary color, or the first primary color, the second primary color, the third primary color and the fourth primary color are different from each other.