Blue Color Conversion Layer for Self-Aligned Micro-LED Fabrication
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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 for different colors onto micro-LEDs, particularly due to alignment accuracy issues with shadow masks and resolution and throughput problems with inkjet and aerosol jet techniques.
Innovation Solution
A photocurable composition including a blue photoluminescent material, monomers, and a photoinitiator is used for self-aligned in-situ curing to form color conversion layers, which absorbs ultraviolet light and emits blue light with high photoluminescence quantum yield, allowing for precise deposition of blue color conversion agents without the need for quantum dots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If shadow masks are used for selective deposition of color conversion agents, then deposition coverage is achieved, but alignment accuracy deteriorates
Solution Approach 1:
The patent combines the color conversion agent deposition with the encapsulant application into a single step. The encapsulant material itself serves as the medium for incorporating and depositing the blue color conversion agent, eliminating the need for separate shadow mask deposition processes and achieving both encapsulation and color conversion in one operation.
Solution Approach 2:
The patent removes the shadow mask component entirely from the fabrication process. Instead of using a shadow mask to define deposition patterns, the invention uses direct photolithographic patterning of the encapsulant layer to achieve the same selective deposition effect without the alignment issues associated with shadow masks.
2Manufacturing precision
If inkjet or aerosol jet printing is used for selective deposition, then resolution can be achieved, but throughput deteriorates
Solution Approach 1:
The patent replaces the mechanical inkjet or aerosol jet printing system with a photolithographic approach. Instead of using mechanical dispensing to achieve selective deposition, the invention uses light-based patterning through photomasks to define the encapsulant regions, which simultaneously determines where the color conversion agent is incorporated, thereby achieving high resolution with much higher throughput.
3Manufacturing precision
If quantum dots are used for blue color conversion, then color accuracy is achieved, but lifetime deteriorates
Solution Approach 1:
The patent changes the material parameter from quantum dots to organic blue photoluminescent materials. This material substitution maintains the desired color accuracy (emission peak in the blue range) while dramatically improving shelf lifetime and stability, as the organic materials are less prone to degradation and aggregation issues that plague quantum dot systems.
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 provides high photoluminescence quantum yield, long lifetime, and long shelf lifetime for blue color conversion agents, enhancing the efficiency and accuracy of micro-LED display fabrication.
Implementation Method 1
a photoinitiator that initiates polymerization of the one or more monomers in response to absorption of the ultraviolet light
Implementation Method 2
The blue photoluminescent material is selected to absorb ultraviolet light with a maximum wavelength in a range of about 300 nm to about 430 nm and to emit blue light
Data Source
AI summary
A display includes a light emitting diode and a color conversion layer that includes a polymer matrix, a blue photoluminescent material, and a components of a photoinitiator that initiated polymerization to form the polymer matrix. The blue photoluminescent material is selected to absorb ultraviolet light with a maximum wavelength in a range of about 300 nm to about 430 nm and to emit blue light. The blue photoluminescent material also has an emission peak in a range of about 420 nm to about 480 nm. The full width at half maximum of the emission peak is less than 100 nm, and the photoluminescence quantum yield is in a range of 5% to 100%.