Color Filter Substrate With Concave-Convex Planarization For Grating Formation
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Solution Overview
Problem
Existing color filter substrates face challenges in forming a polarizing film layer through imprint lithography due to a large step between the black bank and the color filter layer, which prevents complete planarization and affects the formation of a grating structure.
Innovation Solution
A color filter substrate design featuring a base substrate with a black matrix, a color filter layer, and multiple planarization layers, where the second planarization layer has a concave-convex structure to accommodate the black bank and color filter layer, allowing for improved wettability and enabling the formation of a grating layer through nano-imprint lithography.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single planarization layer is used to cover the black bank and color filter layer, then the structure is simple, but the large step between the black bank and color filter layer prevents complete planarization and affects grating structure formation
Solution Approach 1:
The planarization layer is divided into two separate layers: a first planarization layer covering the color filter layer, and a second planarization layer covering the black bank. This segmentation allows each layer to be optimized independently for its specific region, enabling complete planarization despite the large step difference between the black bank and color filter layer, thereby resolving the contradiction between structural simplicity and planarization completeness.
2Strength
If the black bank protrudes significantly above the first planarization layer, then the color filter layer is well-supported, but the large step prevents formation of a complete grating structure through imprint lithography
Solution Approach 1:
The second planarization layer acts as an intermediary element that bridges the height difference between the protruding black bank and the required planar surface for grating formation. By providing this intermediate layer, the black bank maintains its supportive protrusion while the second planarization layer creates a uniform surface that enables complete grating structure formation through imprint lithography, thus resolving the contradiction between support strength and manufacturing ease.
3Ease of manufacture
If the second planarization layer has uniform thickness, then the manufacturing process is simple, but it cannot accommodate both the protruding bank and provide a planar surface for grating layer formation
Solution Approach 1:
The second planarization layer is designed with non-uniform thickness, where the thickness varies to accommodate the protruding black bank while maintaining a planar upper surface. This local variation in thickness allows the layer to adapt to different underlying topographies (protruding bank versus recessed areas), providing both structural accommodation and a uniform surface for grating formation, thereby resolving the contradiction between manufacturing simplicity and adaptability.
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 design eliminates the step between the bank and the color filter layer, facilitating the formation of a complete grating structure and enhancing the performance of the color filter substrate by improving material wettability and contact angles, thus enabling strong color reduction capability and high color gamut in display devices.
Implementation Method 1
a material wettability of the first surface of the first planarization layer to the second planarization layer is greater than a material wettability of the first surface of the bank to the second planarization layer
Data Source
AI summary
A color filter substrate, a manufacturing method thereof and a display device are provided. The color filter substrate includes: a base substrate; a black matrix on the base substrate, the black matrix including a plurality of openings and a bank surrounding each opening; a color filter layer in each opening; a first planarization layer covering the color filter layer, and the bank protruding relative to the first planarization layer in a direction away from the base substrate; a second planarization layer covering both the first planarization layer and the bank, the second planarization layer including a first surface distal to the base substrate; and a grating layer on the second planarization layer. The first surface of the second planarization layer includes a first portion and a second portion, an orthographic projection of the first portion on the base substrate at least partially overlaps with an orthographic projection of the plurality of openings on the base substrate, an orthographic projection of the second portion on the base substrate at least partially overlaps with an orthographic projection of the bank on the base substrate, and a vertical distance between the first portion and a surface of the base substrate close to the second planarization layer is greater than a vertical distance between the second portion and the surface of the base substrate close to the second planarization layer.