Laser Transfer of Phosphor Patterns on LED Substrates
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Solution Overview
Problem
Conventional methods for manufacturing solid-state lighting devices with light-converting materials, such as phosphors, face challenges in controlling chromaticity variations and efficient use of rare earth elements, leading to high manufacturing costs and reduced yields due to poor control over phosphor distribution and recycling.
Innovation Solution
A method and apparatus for precisely coupling light-emitting elements with light-converting materials using a donor substrate that transfers phosphors to a target substrate upon energization, allowing for controlled patterning and reduced waste of rare earth elements by reusing unused donor substrate material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional bulk manufacturing processes are used to apply phosphor coatings to LEDs, then manufacturing simplicity is maintained, but chromaticity control precision deteriorates due to substantial variations in phosphor distribution and LED characteristics
Solution Approach 1:
The patent creates a master template with phosphors pre-arranged in precise patterns before transfer. This preliminary action allows the phosphor distribution to be controlled with high precision, compensating for LED variations without requiring complex real-time adjustment during the coating process.
Solution Approach 2:
The patent introduces a master template as an intermediary carrier that holds the phosphor arrangement. This template serves as a mediator between the phosphor source and the LED, enabling precise phosphor placement while simplifying the actual coating process through a standardized transfer mechanism.
2Manufacturing precision
If phosphors are dispensed in binder solution into cavities, then ease of manufacture is maintained, but phosphor distribution control deteriorates leading to poor conversion efficiency control
Solution Approach 1:
The patent replaces the conventional mechanical dispensing system with a laser-based transfer system. The laser selectively activates adhesive regions on the master template, causing phosphors to transfer to the LED cavity. This substitution enables precise phosphor placement control while maintaining manufacturing simplicity through automation.
Solution Approach 2:
The patent changes the state of the adhesive from permanently bonded to temporarily activated. By using laser energy to locally activate the adhesive in specific patterns, the system achieves precise control over where phosphors are released, transforming the manufacturing process from bulk dispensing to targeted placement.
3Loss of substance
If conventional phosphor dispensing is used, then process simplicity is maintained, but material utilization efficiency deteriorates due to waste of expensive rare earth elements in binder solution
Solution Approach 1:
The patent enables recovery and reuse of the master template after phosphor transfer. The template can be reloaded with phosphors and used again, significantly reducing waste of expensive rare earth elements compared to conventional single-use dispensing methods.
Solution Approach 2:
The patent extracts the phosphor from the binder solution context and places it directly onto the master template in a dry or minimal-binder state. This extraction eliminates the need to dispose of large volumes of binder solution containing wasted phosphors, as the phosphors are precisely placed only where needed.
4Productivity
If LED chromaticity variations are not controlled, then manufacturing cost is reduced through simpler processes, but product quality deteriorates requiring testing and binning that reduces yield
Solution Approach 1:
The patent applies different phosphor patterns to different regions of the master template, which are then transferred to correspond with specific LED characteristics. This local customization approach ensures each LED receives the appropriate phosphor distribution for its specific chromaticity profile, improving overall yield without requiring extensive binning.
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 provides fine control over chromaticity and reduces manufacturing costs by minimizing the use of rare earth elements, achieving high manufacturing yields and enabling the reuse of donor substrate materials.
Implementation Method 1
A laser or other source is used to energize one or more selected locations of the donor substrate, thereby transferring the light-converting material from the donor substrate to the target substrate at the one or more selected locations
Data Source
AI summary
Light-emitting elements such as LEDs are associated with light-converting material such as phosphor and/or other material. A donor substrate comprising the light-converting and/or other material is suitably placed relative to a target substrate associated with the light-emitting elements. A laser or other energy source is then used to transfer the light-converting and/or other material in a pattern via writing or masking from the donor substrate to the target substrate in accordance with the pattern. Addressability and targetability of the transfer process facilitates precise patterning of the target substrate.