Sub-Pixel LED Repair Layout to Prevent Display Short Circuits
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Solution Overview
Problem
Existing display devices face challenges in reducing manufacturing costs and preventing short circuits during the repair of defective light emitting diodes, particularly in organic light emitting display (OLED) devices.
Innovation Solution
The display device incorporates a substrate with sub-pixels featuring a first and second area, where a first light emitting diode is initially integrated, and a second light emitting diode is added during repair, with the bottom surfaces of these diodes on different planes, and a step structure on the electrode connection to facilitate repair and prevent short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If a repair light emitting diode is transferred to replace a defective diode in the same plane, then the repair process is simplified, but short circuit problems occur between the repair diode and existing electrodes
Solution Approach 1:
The patent positions the repair light emitting diode on a different plane (higher or lower z-position) than the original light emitting diodes, rather than replacing in the same plane. This dimensional separation prevents short circuits with existing electrodes while maintaining electrical connectivity through vertically extending connection electrodes, thus resolving the contradiction between repair simplicity and short circuit prevention
Solution Approach 2:
The patent introduces intermediate connection electrodes that extend vertically between different planes to connect the repair light emitting diode with the existing electrode structure. These intermediary electrodes act as mediators that enable electrical connection while maintaining spatial separation, preventing direct short circuits between the repair diode and other components
2Reliability
If the bottom surfaces of first and second light emitting diodes are on different planes, then short circuits are prevented, but manufacturing complexity increases
Solution Approach 1:
The patent designs the connection electrodes to serve multiple functions: they provide electrical connectivity, extend across different planes, and structurally support the repair light emitting diode. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in manufacturing complexity despite the multi-plane configuration
3Ease of repair
If repair light emitting diodes are integrated into the display device structure, then repair capability is enabled, but process costs increase
Solution Approach 1:
The patent pre-integrates repair light emitting diodes and their connection structures into the display device during initial manufacturing, rather than adding them later. This preliminary action enables repair capability to be built-in at no additional post-manufacturing cost, though it does increase initial process complexity and cost, which is traded off against long-term repairability and device reliability
Data Source
AI summary
A display device is disclosed that comprises a substrate and sub-pixels on the substrate that each include a first area and a second area is defined. The display device comprises a plurality of reflective electrodes on the substrate. The display device comprises a plurality of transistors in each of the plurality of sub-pixels on the substrate. The display device comprises a plurality of first light emitting diodes each in the first area of a corresponding sub-pixel. The display device comprises a second light emitting diode in the second area in at least one of the plurality of sub-pixels and is different from the plurality of first light emitting diodes. A bottom surface of the second light emitting diode and bottom surfaces of the plurality of first light emitting diodes are on different planes.