Quantum Dot Photocurable Formulations for Precise Micro-LED Color Conversion
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Solution Overview
Problem
Current methods for fabricating micro-LED displays face challenges in precisely and cost-effectively integrating color conversion agents onto micro-LED panels, particularly due to alignment accuracy issues with shadow masks and resolution, accuracy, and throughput problems with inkjet and aerosol jet techniques.
Innovation Solution
A photocurable composition is developed, comprising nanomaterials that emit radiation in a specific wavelength band in response to absorption of UV or visible light, combined with thiol crosslinkers and photoinitiators, which are used to form a photopolymer that enhances the efficiency and completeness of color conversion layers through thiol-ene polymerization, reducing oxygen inhibition and improving surface curing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If shadow masks are used for selective deposition of color conversion agents, then deposition precision is improved, but alignment accuracy deteriorates and scalability is limited
Solution Approach 1:
The patent replaces the mechanical shadow mask system with a photopolymerization-based selective deposition system. UV-LEDs are activated in specific pixel patterns to initiate photopolymerization of a photocurable composition containing color conversion agents, eliminating the need for physical shadow masks and their associated alignment issues.
Solution Approach 2:
The patent changes the deposition mechanism from mechanical blocking (shadow masks) to photochemical activation (UV-LED patterned illumination). By controlling the wavelength and intensity of UV-LED light, the system achieves precise spatial control over color conversion agent deposition without mechanical alignment constraints.
2Device complexity
If inkjet or aerosol jet printing is used for selective deposition of color conversion agents, then device complexity is reduced, but resolution and placement accuracy deteriorate
Solution Approach 1:
The patent replaces inkjet/aerosol jet printing mechanisms with a photopolymerization-based system. Instead of mechanically ejecting material droplets, the system uses UV-LED activated photopolymerization to selectively solidify and retain color conversion agents at desired pixel locations, achieving higher precision without complex printing hardware.
3Device complexity
If conventional acrylate polymerization is used without thiol crosslinkers, then formulation simplicity is maintained, but surface curing completeness deteriorates due to oxygen inhibition
Solution Approach 1:
The patent creates a composite photopolymerization system combining acrylate monomers with thiol crosslinkers. This composite formulation leverages the complementary mechanisms of free radical polymerization (acrylate) and thiol-ene click chemistry (thiol), where the thiol component specifically counteracts oxygen inhibition to achieve complete surface curing while maintaining formulation practicality.
Solution Approach 2:
The thiol crosslinker acts as an intermediary that mediates between oxygen (the harmful factor) and the acrylate polymerization process. The thiol preferentially reacts with oxygen-derived radicals, protecting the acrylate polymerization from inhibition and enabling complete surface curing.
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 enables precise and efficient deposition of color conversion layers, improving the yield and throughput of micro-LED displays by ensuring complete and uniform curing of the photopolymer, thereby enhancing the color conversion efficiency and stability of the micro-LED panels.
Implementation Method 1
a photoinitiator that initiates polymerization of the one or more (meth)acrylate monomers in response to absorption of radiation in the second wavelength band
Implementation Method 2
a nanomaterial selected to emit radiation in a first wavelength band in the visible light range in response to absorption of radiation in a second wavelength band
Implementation Method 3
one or more thiol crosslinkers, wherein the thiol crosslinkers provide for complete network formation upon curing of the photocurable composition
Data Source
AI summary
A photocurable composition includes a nanomaterial selected to emit radiation in a first wavelength band in the visible light range in response to absorption of radiation in a second wavelength band in the UV or visible light range. The second wavelength band is different than the first wavelength band. The photocurable composition further includes one or more (meth)acrylate monomers, a thiol crosslinker, and a photoinitiator that initiates polymerization of the one or more (meth)acrylate monomers in response to absorption of radiation in the second wavelength band. A light-emitting device includes a plurality of light-emitting diodes and the cured photocurable composition in contact with a surface through which radiation in a first wavelength band in the UV or visible light range is emitted from each of the light-emitting diodes.