Quantum Dot Color Filter Substrate Manufacturing via Grey Level Photoresist Patterning
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Solution Overview
Problem
The development of quantum dot color filter substrates for TFT-LCDs is hindered by the reactivity of nanometer quantum dots with photo initiators in traditional photoresist materials, leading to reduced light emission efficiency and material waste, and the complexity of photolithography processes.
Innovation Solution
A method involving the use of grey level patterns on a photo mask to form pixel barrier walls and spacers through exposure and development, followed by inkjet printing of patterned quantum dot layers, which simplifies operations, reduces material waste, and enhances the accuracy and efficiency of quantum dot placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If quantum dots are dispersed in traditional photoresist for photolithography, then color filter layers can be formed, but light emission efficiency is reduced due to reaction between quantum dots and photo initiators
Solution Approach 1:
The patent extracts quantum dots from the photoresist composition entirely, using them only as inkjet printing materials to form color filter layers, thereby eliminating the harmful interaction between quantum dots and photo initiators while maintaining manufacturing capability
Solution Approach 2:
The patent introduces a dual-layer photoresist system where a black photoresist layer serves as an intermediary that absorbs UV light and prevents it from reaching the quantum dot-containing transparent photoresist layer, thereby protecting quantum dots from photo initiator reaction while still enabling photolithography processing
2Manufacturing precision
If photolithography development process is used to form color filter patterns, then precise patterning can be achieved, but quantum dot material is wasted due to removal of unnecessary portions
Solution Approach 1:
The patent performs preliminary patterning of the transparent photoresist layer using photolithography to define precise patterns, then uses inkjet printing to deposit quantum dots only in the required areas, thereby achieving precise patterning without wasting quantum dot material in subsequent development removal
Solution Approach 2:
The patent replaces the chemical development process that removes material with a selective deposition process using inkjet printing, where quantum dots are deposited only where needed based on pre-defined patterns, eliminating material waste associated with development removal
3Loss of substance
If inkjet printing is used to deposit quantum dot ink, then material utilization is improved, but circular print dots are formed instead of desired sub-pixel shapes
Solution Approach 1:
The patent performs preliminary patterning of the transparent photoresist layer using photolithography with grey level patterns that define the precise sub-pixel shapes, then uses inkjet printing to deposit quantum dots that conform to these pre-defined patterns, thereby achieving both material efficiency and shape accuracy
Solution Approach 2:
The patent applies different properties to different regions: the transparent photoresist layer contains quantum dots and is patterned with precise geometries, while the black photoresist layer provides UV absorption. The inkjet printing deposits quantum dots with local precision matching the underlying pattern, achieving shape accuracy without material waste
4Productivity
If grey level patterns are used in photo mask for exposure, then pixel barrier walls and spacers are formed in one process, but process complexity increases
Solution Approach 1:
The patent designs the photo mask with grey level patterns that serve multiple functions simultaneously: defining pixel barrier wall positions, determining spacer locations, and controlling photoresist thickness variations. This multi-functionality consolidates what would otherwise require multiple separate patterning steps into one exposure process, improving productivity despite increased mask design complexity
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 method improves the accuracy of inkjet printing, reduces facility installation costs, and optimizes the utilization of quantum dot materials, resulting in a more efficient and cost-effective manufacturing process for quantum dot color filter substrates with high light emission efficiency.
Implementation Method 1
coating and forming a black photoresist layer on the backing plate... wherein the black photoresist layer has a light absorption capability
Implementation Method 2
subjecting the transparent photoresist layer to exposure with ultraviolet light through the photo mask
Implementation Method 3
forming patterned quantum dot layers in zones delimited and surrounded by the pixel barrier walls through inkjet printing
Data Source
AI summary
The present invention provides a method for manufacturing a quantum dot color filter substrate, in which a black photoresist layer and a transparent photoresist layer are first coated and formed on a backing plate in sequence and then, first, second, and third patterns of a photo mask having different grey levels are used to pattern the black photoresist layer and the transparent photoresist layer to obtain a plurality of transparent barrier walls corresponding to the first pattern, sub spacers corresponding to the second pattern and located on the transparent barrier walls, and main spacers corresponding to the third pattern and located on the transparent barrier walls and also to obtain a plurality of black barrier walls covered by the plurality of transparent barrier walls, the plurality of black barrier walls and the plurality of transparent barrier walls located thereon collectively defining a plurality of pixel barrier walls; and then, patterned quantum dot layers are formed in sub-pixel zones that are delimited and surrounded by the plurality of pixel barrier walls by means of inkjet printing such that accuracy of inkjet printing is greatly improved.