MicroLED Transfer Assembly for Selective Pixel Repair
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Solution Overview
Problem
Current methods for assembling microLED displays face challenges in achieving high pixel yield due to the inability to selectively transfer and replace defective microLEDs, leading to inefficiencies in manufacturing and low yield rates.
Innovation Solution
A system and method utilizing a transfer substrate with temperature-responsive transfer elements that can selectively pick up and release microLED chips, allowing for the transfer of only functional chips and the replacement of defective ones, enabling parallel pixel repair and vacancy filling on demand.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional assembly methods are used to transfer microLED chips, then the assembly process can be completed, but the pixel yield is low due to inability to selectively replace defective microLEDs
Solution Approach 1:
The patent applies preliminary action by performing defect detection and selective transfer of functional microLEDs before final assembly. The system identifies defective chips early in the process and replaces them proactively, ensuring high pixel yield before the display is completed. This prevents defective chips from being permanently bonded into the final product.
Solution Approach 2:
The patent uses an intermediary temporary substrate as a mediator between the microLED source and the final display substrate. This temporary substrate allows for selective transfer and replacement of microLEDs without permanent bonding, enabling defect correction and optimization of pixel yield before final assembly.
2Reliability
If all microLED chips are transferred without selection, then the transfer process is simple, but defective chips cannot be replaced leading to low yield rates
Solution Approach 1:
The patent applies local quality by enabling selective transfer of individual microLED chips or specific groups based on their functional status. The system can choose to transfer only functional chips to specific locations on the temporary substrate, while leaving defective chips behind for replacement with functional ones, thereby optimizing yield rate through localized quality control.
Solution Approach 2:
The patent implements dynamics by making the transfer process adaptable and reconfigurable. The system can dynamically adjust which chips are transferred based on real-time defect detection, allowing multiple transfer cycles with different selection criteria. This dynamic approach enables optimization of yield rate by replacing defective chips with functional ones in subsequent transfer cycles.
3Ease of repair
If permanent bonding is used for microLED assembly, then the assembly is stable, but defective microLEDs cannot be replaced
Solution Approach 1:
The patent applies preliminary action by performing all selective transfer and replacement operations on a temporary substrate before final permanent bonding to the display substrate. This allows defect replacement capability to be exercised while maintaining assembly stability during the temporary phase, and then achieves permanent stable bonding only after all replacements are complete.
Solution Approach 2:
The patent uses a temporary substrate as an intermediary that provides both stability and replaceability during the assembly process. This mediator allows defective microLEDs to be replaced while maintaining stable temporary bonds, and only after all replacements are complete does the system proceed to permanent bonding, thus achieving both ease of repair and assembly stability.
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 enhances the microLED display assembly process by improving yield rates and reducing manufacturing costs through selective and efficient transfer of microLEDs, ensuring high-quality pixel assembly without permanent bonding.
Implementation Method 1
A system and method utilizing a transfer substrate with temperature-responsive transfer elements that can selectively pick up and release microLED chips
Implementation Method 2
The first coupon substrate has a first, soft adhesive layer that temporarily holds the microLED chips
Data Source
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AI summary
MicroLED chips are transferred from an epitaxy wafer to a first coupon substrate. The first coupon substrate has a first, soft adhesive layer that temporarily holds the microLED chips. Using a first transfer substrate, a subset of the microLED chips are transferred from the first coupon substrate to a second coupon substrate having a second, soft adhesive layer. A pattern of microLED chips are transferred from another substrate to the second coupon substrate via a second transfer substrate to fill vacancies in the subset of microLED chips. The transfer substrates are operable to hold and release pluralities of micro objects.