Blue Color Conversion Layer for Precise Micro-LED Patterning
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Solution Overview
Problem
The integration of multiple color micro-LEDs onto a single panel is challenging due to the need for precise placement and the limitations of existing color conversion methods, such as shadow masks, inkjet, and aerosol jet printing, which face issues with accuracy, scalability, and throughput in manufacturing micro-LED displays.
Innovation Solution
A photocurable composition comprising a blue photoluminescent material, monomers, and a photoinitiator is used to form a color conversion layer by selective deposition and in-situ curing, allowing for precise and cost-effective application of blue color converters on micro-LEDs, converting ultraviolet light into blue light with high photoluminescence quantum yield and long shelf lifetime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If shadow masks are used for selective deposition of color conversion agents, then color conversion can be achieved, but alignment accuracy and scalability are compromised
Solution Approach 1:
The patent replaces the mechanical shadow mask system with a photolithography-based chemical system. Instead of physically blocking light with masks, the invention uses photomasks and photoresist materials where UV light patterns are used to selectively cure polymer matrices containing color conversion agents only in desired pixel locations, achieving both precision and scalability.
Solution Approach 2:
The invention changes the state of the color conversion agent material from a static deposited layer to a photocurable fluid that transitions from liquid to solid state upon UV exposure. This parameter change (phase transition via photopolymerization) enables precise spatial control and eliminates alignment issues inherent in mechanical mask systems.
2Manufacturing precision
If inkjet printing is used for selective deposition of color conversion agents, then deposition can be performed, but resolution and accuracy are limited
Solution Approach 1:
The patent uses photomasks that are optical copies or patterns transferred through light to define pixel locations. The UV light pattern acts as a template that reproduces the desired color conversion layer geometry, achieving high resolution and accuracy without the mechanical limitations of inkjet droplet placement.
3Manufacturing precision
If aerosol jet printing is used for selective deposition of color conversion agents, then deposition can be achieved, but throughput is reduced
Solution Approach 1:
The photolithography process described in the patent is inherently continuous - UV light can be applied across the entire substrate simultaneously through a photomask, and the photocurable fluid cures continuously upon exposure. This eliminates the sequential nature of aerosol jet printing, dramatically improving throughput while maintaining precision.
4Adaptability or versatility
If monochrome LEDs are used with color conversion agents, then integration of multiple colors can be achieved, but the conversion efficiency and lifetime of blue color converters are insufficient
Solution Approach 1:
The patent employs composite material formulations where color conversion agents (such as quantum dots or phosphors) are embedded within a photocurable polymer matrix. This composite structure protects the color conversion agents, improves their stability and lifetime, while maintaining high conversion efficiency through optimized material composition and photopolymerization conditions.
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 enables high-efficiency blue color conversion with improved accuracy and scalability, enhancing the manufacturing process for micro-LED displays by providing a reliable and long-lasting blue color conversion layer.
Implementation Method 1
a blue photoluminescent material 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
Implementation Method 2
a photoinitiator that initiates polymerization of the one or more monomers in response to absorption of the ultraviolet light
Data Source
AI summary
A photocurable composition includes a blue photoluminescent material, one or more monomers, and a photoinitiator that initiates polymerization of the one or more monomers in response to absorption of the ultraviolet light. 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%.