Micro-LED Transfer Substrates for Higher Yield Pixel Placement
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Solution Overview
Problem
The manufacturing process of micro-LED displays faces challenges in transfer yield and cost due to variations in the transfer process, necessitating methods to enhance transfer efficiency and reduce costs.
Innovation Solution
The use of micro-LED transferring substrates with multiple transfer regions of varying sizes and shapes, allowing for sequential transfer of micro-LEDs of different sizes and shapes, including polygon and circular forms, to increase transfer efficiency and reduce the need for repair processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a wet transfer method is used to transfer micro-LEDs, then transfer cost is reduced, but transfer yield varies and may decrease
Solution Approach 1:
The transferring substrate is divided into multiple transfer regions (first transfer region, second transfer region, third transfer region) with different sizes and shapes. Each region is optimized for transferring micro-LEDs of specific sizes, allowing systematic coverage of all sub-pixel regions and improving overall transfer yield while maintaining cost-effectiveness of the wet transfer method
Solution Approach 2:
Different transfer regions are designed with locally optimized characteristics - the first transfer region has a size matching the largest micro-LEDs, the second transfer region targets medium-sized micro-LEDs, and the third transfer region handles smallest micro-LEDs. This local optimization ensures high transfer yield for each micro-LED size category while maintaining overall process simplicity
2Ease of manufacture
If micro-LEDs of uniform size and shape are used, then manufacturing process is simplified, but transfer efficiency decreases due to untransferred regions
Solution Approach 1:
The patent employs micro-LEDs with varied size parameters (large, medium, small) and shape parameters (polygonal, circular) to match different transfer region dimensions. This parameter variation enables complete coverage of all sub-pixel regions without leaving untransferred gaps, thereby maximizing transfer efficiency while maintaining a relatively simple manufacturing process
3Productivity
If transfer regions are designed with varying sizes and shapes, then transfer efficiency increases, but device complexity increases
Solution Approach 1:
The transferring substrate is segmented into distinct transfer regions with defined boundaries and characteristics. This segmentation approach systematically organizes the complexity by creating clearly defined zones for different micro-LED sizes, making the complex structure manageable and manufacturable while achieving high transfer efficiency
Solution Approach 2:
The transferring substrate serves multiple functions simultaneously: it acts as a transfer carrier, a sorting mechanism for different micro-LED sizes, and a placement template for various sub-pixel regions. This multi-functionality consolidates what could be multiple separate processes into a single versatile substrate design
Data Source
AI summary
Provided is a micro-LED display, a micro-LED transferring substrate, and a method of transferring micro-LEDs using the micro-LED transferring substrate. The micro-LED includes a backplane substrate; and a plurality of sub-pixels provided on the backplane substrate, wherein at least one sub-pixel from among the plurality of sub-pixels includes a first micro-LED; and a second micro-LED different from the first micro-LED.