Ribbed Micro-Cavity Imprinting for Uniform Color Filter Arrays
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Solution Overview
Problem
Current methods for forming large-format color filter arrays are inefficient due to high costs, material wastage, and difficulty in achieving uniformity and high fill factors, particularly in imprint-and-fill processes which struggle with capillary flow and differential evaporation issues.
Innovation Solution
A method involving a substrate with a curable layer imprinted to form micro-cavities and ribs, allowing for uniform filling and curing of curable materials within these structures, which increases manufacturing speed and reduces material requirements, enabling larger fill-factor substrates with improved uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photolithographic processes are used to form color filter arrays, then color filters can be formed on substrates, but the process is expensive, time consuming, and wasteful of materials
Solution Approach 1:
The patent replaces the photolithographic process (optical/mechanical system involving light exposure, photoresist, and etching) with a direct imprinting process using a stamp or mold. The curable material is mechanically pressed into cavities formed in the stamp, eliminating the need for photoresist coating, UV exposure, and chemical etching steps. This substitution dramatically reduces manufacturing time and material waste while maintaining pattern accuracy.
Solution Approach 2:
The patent extracts and eliminates unnecessary intermediate steps from the photolithographic process. Specifically, it removes the photoresist layer, the UV exposure step, and the chemical etching step by directly forming cavities in the curable material through mechanical imprinting. This extraction of redundant steps simplifies the process and improves productivity.
2Productivity
If imprinting processes are used to form large-format structures, then manufacturing speed increases, but uniformity and fill factor are difficult to achieve due to capillary flow and differential evaporation
Solution Approach 1:
The patent segments the large-format substrate into multiple smaller cavities arranged in an array, with each cavity sized to prevent capillary flow issues. By dividing the continuous large-area imprinting into discrete smaller units, uniform filling is achieved while maintaining large overall substrate coverage and high fill factors.
Solution Approach 2:
The patent optimizes the local geometry of each cavity (size, shape, depth) to control capillary forces and prevent differential evaporation. The cavities are designed with specific dimensional characteristics that ensure uniform material distribution, addressing the local quality issue while achieving global uniformity across the large substrate.
3Manufacturing precision
If subtractive photolithographic processes are used, then color filters can be formed, but material wastage is high due to etching and additional material requirements
Solution Approach 1:
The patent inverts the traditional subtractive approach by using an additive process. Instead of starting with a continuous layer and removing material through etching, the curable material is directly formed into cavities through imprinting. This inversion from subtraction to addition eliminates material waste from etching processes and removes the need for photoresist and other consumable materials.
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 approach results in larger, uniformly filled imprinted structures with increased manufacturing efficiency and reduced material usage, effectively addressing the limitations of existing technologies by ensuring consistent color filtration across larger areas.
Implementation Method 1
The curable layer is imprinted and cured to form a cured layer including a layer surface and one or more micro-cavities
Data Source
AI summary
A method of making a filled large-format imprinted structure includes providing a substrate, locating a curable layer over the substrate, imprinting the curable layer, and curing the curable layer to form a cured layer including a layer surface and one or more imprinted micro-cavities. Each micro-cavity has a micro-cavity depth and a micro-cavity width and one or more ribs extending from the bottom of the micro-cavity toward the top of the micro-cavity. Each rib has a rib width that is less than one half of the micro-cavity width, a rib height that is less than the micro-cavity depth, and each rib separates the micro-cavity into portions, each portion having a portion width less than or equal to 20 microns. A curable material is located in each micro-cavity and cured to form cured material located in each micro-cavity, thereby defining a filled large-format imprinted structure.