Micro LED Bonding Layout for Defective Pixel Repair
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Solution Overview
Problem
The manufacturing process of micro LED displays is hindered by mechanical transfer errors, leading to alignment and damage issues during the transfer and placement of micro LEDs, resulting in defective pixels and a need for complex repair processes.
Innovation Solution
A display device design that includes a circuit substrate with sub-pixels having specific bonding areas, where light-emitting elements are bonded using solder structures and conductive adhesive structures, allowing for efficient removal and replacement of faulty elements to minimize defective pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If mechanical transfer operations are used to transfer micro LEDs to circuit substrate, then transfer efficiency can be improved, but alignment accuracy and placement precision deteriorate due to machine operation errors
Solution Approach 1:
The patent replaces the mechanical transfer system with a direct growth transfer method where micro LEDs are grown directly on the circuit substrate in predetermined positions. This eliminates mechanical transfer operations entirely, thereby resolving the contradiction between transfer efficiency and alignment accuracy by removing the source of machine operation errors while maintaining high productivity through direct in-situ growth and activation of multiple micro LEDs simultaneously
2Productivity
If mechanical transfer operations are used to place micro LEDs on substrate, then placement speed can be improved, but placement precision deteriorates due to machine operation errors
Solution Approach 1:
The patent replaces mechanical placement operations with a direct growth method where micro LEDs are formed directly at their final positions on the circuit substrate. This eliminates the need for mechanical placement while achieving high productivity through parallel growth processes and simultaneous activation of multiple micro LEDs, thereby resolving the contradiction between placement speed and placement precision
3Ease of manufacture
If conventional bonding methods are used for light-emitting elements, then manufacturing process is simpler, but repair capability is reduced due to inability to easily remove and replace faulty elements
Solution Approach 1:
The patent segments the bonding process into two distinct stages: first, a preliminary bonding stage using conductive adhesive to temporarily secure micro LEDs, and second, a final bonding stage using soldering to create permanent connections. This segmentation allows faulty micro LEDs to be easily removed and replaced during the preliminary bonding stage before final soldering, thereby resolving the contradiction between manufacturing simplicity and repair capability by introducing a reversible intermediate step
Solution Approach 2:
The patent performs preliminary bonding with conductive adhesive before final soldering, creating a temporary but functional connection that allows for easy removal and replacement of micro LEDs. This preliminary action enables repair operations to be performed before the final irreversible bonding step, resolving the contradiction between manufacturing simplicity and repair capability by providing a window of opportunity for corrections
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 reduces the number of defective pixels by enabling effective repair processes through the strategic use of bonding areas and adhesive structures, improving the yield and reliability of micro LED display manufacturing.
Implementation Method 1
bonded to the circuit substrate through a first solder structure
Implementation Method 2
bonded to the circuit substrate through a first conductive adhesive structure
Data Source
AI summary
A display device includes a circuit substrate and first to third light-emitting elements. The circuit substrate has first to third sub-pixels. Each of the first to third sub-pixels has a first bonding area and a second bonding area. The first light-emitting element is located in the first bonding area of the first sub-pixel, and is bonded to the circuit substrate through a first solder structure. The second light-emitting element is located in the second sub-pixel. There is first residual solder on the first bonding area of the second sub-pixel. The third light-emitting element is located on one of the first bonding area and the second bonding area of the third sub-pixel, and is bonded to the circuit substrate through a conductive adhesive structure.