Micro-LED Transfer Layout Using Expansion Film and Laser Positioning
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Solution Overview
Problem
Current display device manufacturing methods face challenges in accurately transferring light emitting elements to pixels without losing elements and in reducing defective transfer rates, due to the complexity of spacing and positioning these elements during the transfer process.
Innovation Solution
A manufacturing apparatus and method that involves transferring light emitting elements onto a first film, expanding the film to create sufficient distance between elements, retransferring them to a second film, and using a guide laser to determine positions, allowing for precise transfer of one light emitting element per pixel with a single laser shot, thereby reducing element loss and defective transfers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If light emitting elements are transferred directly from growth substrate to pixel substrate without expansion, then transfer process is simpler, but spacing and positioning precision deteriorates causing element loss and defective transfers
Solution Approach 1:
The patent introduces an expansion film as an intermediary carrier between the growth substrate and the final pixel substrate. The light emitting elements are first transferred to the expansion film, which provides a controlled environment for spacing adjustment through expansion, before final transfer to the pixel substrate. This intermediary step resolves the positioning precision problem without requiring direct complex manipulation.
Solution Approach 2:
The expansion film allows preliminary spacing adjustment of light emitting elements before final transfer to the pixel substrate. By expanding the film after initial transfer but before final placement, the system pre-establishes correct spacing and positioning, simplifying the subsequent final transfer process and improving overall positioning precision.
2Productivity
If multiple light emitting elements are transferred simultaneously, then productivity increases, but positioning accuracy and element integrity deteriorates
Solution Approach 1:
The transfer process is segmented into distinct phases: initial batch transfer to expansion film, expansion/spacing adjustment phase, and final individual placement on pixel substrate. This segmentation allows simultaneous transfer of multiple elements in the first phase while ensuring individual positioning accuracy in the final phase through the intermediary expansion step.
3Reliability
If spacing between light emitting elements is insufficient, then device area is reduced, but transfer reliability deteriorates due to difficulty in precise positioning
Solution Approach 1:
The expansion film provides dynamic spacing adjustment capability. Initially, elements can be transferred with minimal spacing to maintain compact area, then the film is expanded to increase spacing between elements, improving positioning reliability during final transfer. This dynamic adjustment resolves the contradiction between compact area and reliable positioning.
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 enables a more efficient and accurate transfer process, reducing the number of lost light emitting elements and defective transfers, while allowing for precise control of the laser shot position, resulting in improved manufacturing efficiency and quality.
Implementation Method 1
a seventh unit configured to transfer one light emitting element to a bonding electrode of one pixel by irradiating a laser beam using a laser shot
Data Source
AI summary
A manufacturing apparatus of a display device, includes: a first unit to transfer a plurality of light emitting elements on a growth substrate to a first film; a second unit to expand the first film; a third unit to retransfer the plurality of light emitting elements to a second film; a fourth unit to determine positions of the plurality of light emitting elements on the second film; a fifth unit to bin the light emitting elements on the second film, and determine an effective light source from among the light emitting elements; a sixth unit to form a plurality of pixels on a substrate, each pixel including a first bonding electrode; a seventh unit to remove the second film after transferring one light emitting element to the first bonding electrode of one pixel; and an eighth unit to form a second electrode on the one light emitting element.