Micro LED Mass Transfer via Intermediary Substrates
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Solution Overview
Problem
Existing mass transfer methods for micro light emitting diodes (micro LEDs) face challenges in efficiently and cost-effectively transferring millions of small micro LEDs from a component substrate to a circuit substrate, particularly in achieving high resolution and brightness while minimizing power consumption.
Innovation Solution
The proposed method involves a two-step process using a first medium load substrate with patterned bonding structures to pick up micro LEDs from a component substrate and transfer them to a second medium load substrate, which then aligns with a target substrate for direct transfer into sub-pixels, utilizing techniques such as laser or heating drying for separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional direct transfer methods are used to move micro LEDs from component substrate to circuit substrate, then the process is simple, but transfer efficiency is low and precision is insufficient for high resolution displays
Solution Approach 1:
The patent introduces a medium load substrate as an intermediary carrier between the component substrate and circuit substrate. This mediator enables indirect transfer of micro LEDs in two stages: first from component substrate to medium load substrate, then from medium load substrate to circuit substrate. This intermediary approach resolves the contradiction by achieving high transfer efficiency and precision through the bonding structures on the medium load substrate, while keeping each individual transfer step manageable in complexity.
Solution Approach 2:
The transfer process is divided into two separate stages using the medium load substrate. The first stage transfers micro LEDs from the component substrate to the medium load substrate, and the second stage transfers them from the medium load substrate to the circuit substrate. This segmentation allows each stage to be optimized independently, achieving high overall transfer efficiency and precision without overwhelming process complexity.
2Manufacturing precision
If multiple substrates are used to ensure high precision transfer, then transfer precision improves, but the number of substrates and costs increase
Solution Approach 1:
The medium load substrate serves multiple functions: it acts as a temporary carrier for micro LEDs, provides a platform for forming precise bonding structures, and facilitates the transfer process. This multi-functional design achieves high transfer precision without requiring an excessive number of specialized substrates, as the medium load substrate handles multiple roles in the transfer process.
Solution Approach 2:
The medium load substrate is used temporarily during the transfer process and then discarded or reused. This approach allows high precision transfer to be achieved with a limited number of substrates, as the medium load substrate can be recovered or replaced without requiring permanent retention of multiple specialized substrates, thereby reducing the overall quantity of substrates needed.
3Reliability
If bonding structures are formed on each substrate, then transfer reliability improves, but manufacturing complexity and costs increase
Solution Approach 1:
The bonding structures are formed on the medium load substrate and used for both transfer stages. This merging of the bonding function onto a single substrate reduces the overall manufacturing complexity compared to forming separate bonding structures on each substrate, while maintaining high transfer reliability through the repeated use of the same bonding structures.
Solution Approach 2:
The bonding structures on the medium load substrate are used temporarily for the transfer process and then the medium load substrate can be discarded or the bonding structures recovered. This approach achieves high transfer reliability through proper bonding while avoiding the need for permanent, complex bonding structures on every substrate, thereby improving manufacturing ease.
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 enhances transfer efficiency by allowing selective and repeated use of bonding structures, reduces the number of substrates needed, and minimizes costs, while ensuring high precision and stability in transferring micro LEDs into sub-pixels on the target substrate.
Implementation Method 1
bonding structures on a first medium load substrate to pick up the micro light emitting diodes
Implementation Method 2
separating the component substrate from the to-be-picked-up micro light emitting diodes by adopting a laser or heating drying process
Data Source
Figure 1
Figure 2a
Figure 2b~3a
AI summary
The present disclosure discloses a mass transfer method and system for micro light emitting diodes, wherein the mass transfer method includes: providing a component substrate on which a plurality of micro light emitting diodes are formed; picking up the micro light emitting diodes on the component substrate at least once by a plurality of bonding structures on a first medium load substrate, and transferring micro light emitting diodes picked up every time to a second medium load substrate; and transferring the micro light emitting diodes on the second medium load substrate into corresponding sub-pixels on a target substrate at one time, wherein one of the micro light emitting diodes on the second medium load substrate corresponds to one of the sub-pixels on the target substrate.