Stacked Transparent Substrate Repair for Defective Micro LED Displays
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Solution Overview
Problem
Existing micro LED repair methods are costly and labor-intensive due to the need for delicate removal and re-mounting processes that require avoiding damage to interconnect patterns, complicating the repair process.
Innovation Solution
A display device and repair method involving a stacked transparent substrate with a repair LED arranged to correspond to defective LEDs on a first substrate, allowing simultaneous driving of LEDs on both substrates to compensate for defects without removing the defective LEDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the defective micro LED is removed by heating with a laser, then the defective LED can be eliminated, but the interconnect pattern may be damaged and the process becomes complex and costly
Solution Approach 1:
The patent transitions from a two-dimensional planar repair approach (removing defective LEDs from the substrate) to a three-dimensional stacked approach (placing a repair substrate above the defective substrate). This dimensional change allows the repair LED to be positioned directly above the defective LED without requiring removal, thus avoiding damage to interconnect patterns while eliminating the defective LED's visual impact.
Solution Approach 2:
The patent introduces a transparent repair substrate as an intermediary layer between the viewer and the defective substrate. This intermediary contains repair LEDs that are positioned to correspond with defective LEDs, allowing the repair function to be performed without directly manipulating or removing components from the original substrate, thereby preserving interconnect integrity.
2Reliability
If the defective micro LED is removed by heating with a laser, then the defective LED can be eliminated, but delicate work and many steps are required resulting in great increase in cost
Solution Approach 1:
By moving the repair operation to a third dimension (stacking the repair substrate above the defective substrate), the patent eliminates the need for complex laser heating and removal processes. The repair LED is simply mounted on the transparent substrate at the corresponding position, dramatically simplifying the manufacturing process and reducing costs.
Solution Approach 2:
The patent creates a copy of the substrate structure (repair substrate with repair LED) that mirrors the original substrate's LED arrangement. This copying approach allows the repair function to be implemented by placing a duplicate structure above the defective one, avoiding the need for complex removal and reassembly operations.
3Ease of repair
If a transparent substrate is stacked on the first substrate with a repair LED at the corresponding position, then the repair process is simplified and costs are reduced, but the structure becomes more complex
Solution Approach 1:
The transparent repair substrate serves multiple functions simultaneously: it acts as a structural support for the repair LED, provides optical transparency to allow viewing through the display, and positions the repair LED precisely above the defective LED. This multi-functionality reduces the need for additional components and simplifies the overall repair structure despite the stacked configuration.
Data Source
Figure 1~2
Figure 3
Figure 4A~4B
AI summary
A display device includes a first substrate including a plurality of light-emitting elements arranged two-dimensionally, and a second substrate stacked on the first substrate. At least the second substrate is transparent. The second substrate includes a repair light-emitting element arranged on the second substrate at a position thereon that corresponds to a defective light-emitting element on the first substrate.