Micro-LED Transfer Substrate Recess Geometry for High-Yield Assembly
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Solution Overview
Problem
The productivity of micro-LED display apparatus manufacturing decreases as the size of micro-LEDs decreases and the size of displays increases, due to the inefficiencies of the pick and place method used in transferring micro-LEDs.
Innovation Solution
A device transfer substrate with recesses having specific geometric configurations, allowing for high-yield transfer and arrangement of light emitting devices using fluidic or dry self-assembly methods, ensuring each recess accommodates only one device and facilitates electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pick and place method is used to transfer micro-LEDs, then the transfer process can be performed, but productivity decreases as the size of micro-LEDs decreases and the size of displays increases
Solution Approach 1:
The device transfer substrate is divided into multiple recesses, each capable of receiving and holding a micro-LED device. This segmentation allows simultaneous transfer of multiple devices in one operation, dramatically improving productivity compared to sequential pick-and-place methods while reducing the total number of devices needed for the transfer process
Solution Approach 2:
The device transfer substrate acts as an intermediary carrier that temporarily holds multiple micro-LED devices in its recesses. This intermediary structure enables batch transfer operations, improving productivity by transferring multiple devices at once rather than one by one, while the substrate itself is not consumed in the process
2Reliability
If the pick and place method is used to transfer micro-LEDs, then the transfer process can be performed, but the transfer yield decreases
Solution Approach 1:
Each recess in the device transfer substrate is specifically designed with dimensions and geometry that correspond to the micro-LED device size. This segmentation into precisely configured recesses ensures high transfer yield by providing dedicated holding positions for each device, preventing loss or misplacement during transfer operations
Solution Approach 2:
The recesses are designed to automatically hold and position micro-LED devices through their geometric configuration alone, without requiring additional mechanical gripping or positioning mechanisms. This self-service approach improves both transfer yield and productivity by enabling reliable device holding through the recess geometry itself
3Reliability
If redundant light emitting devices are used in the transfer process, then device loss is compensated, but the amount of light emitting devices needed increases
Solution Approach 1:
The substrate is segmented into multiple discrete recesses, each designed to hold exactly one micro-LED device. This precise segmentation eliminates the need for excessive redundancy while maintaining high transfer yield, as each recess provides a dedicated, secure position for its corresponding device
Solution Approach 2:
The recess geometry is designed as a precise copy or template of the micro-LED device footprint. By creating recesses that exactly match device dimensions, the system achieves high transfer yield without requiring additional redundant devices, as each recess securely holds its designated device
Data Source
AI summary
A device transfer substrate includes a plurality of recesses, wherein each of the plurality of recesses includes a first region having a shape of a first figure, a second region having a shape of a second figure, and an overlapping region formed as a portion of the first region partially overlaps a portion of the second region, wherein a maximum width of the overlapping region in a direction intersecting with a straight line passing through a center of the first figure and a center of the second figure is less than a diameter or a diagonal length of the first figure and less than a diameter or a diagonal length of the second figure.