Display Repair Structure with Redundant Transistor and Welding Pattern
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Solution Overview
Problem
Defective pixels in display devices, caused by minute foreign substances during manufacturing, lead to lightened or blackened pixels, resulting in degraded fabrication yield and increased costs, with existing repair processes being ineffective and often leading to discarding of display panels.
Innovation Solution
A display device with a repair structure that includes a series or parallel connection of transistors, where a second transistor can operate as a redundancy to replace a defective first transistor, and a welding pattern is used to connect or disable nodes to enable current flow, allowing the defective pixel to function as a normal pixel, with luminance compensation through data voltage adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a repair process is performed on defective pixels, then the defective pixel can be restored to operate as a normal pixel, but the manufacturing complexity and process difficulty increase
Solution Approach 1:
A second transistor is preliminarily configured in parallel with the first transistor before manufacturing defects occur. This redundant transistor remains inactive during normal operation but can be activated through a repair process if the first transistor becomes defective, allowing restoration of pixel functionality without requiring complete pixel replacement
Solution Approach 2:
The electrical connection state of the second transistor is changed from disconnected to connected through a welding repair process. By controlling the welding parameters, the second transistor can be selectively activated to replace the defective first transistor, enabling parameter-based switching between operational and standby states
2Ease of operation
If a welding pattern is used to connect or disable transistor nodes, then current flow can be controlled to enable defective pixel operation, but the manufacturing precision requirements increase
Solution Approach 1:
A welding pattern serves as an intermediary element between the first and second transistors. This welding pattern can be selectively connected or disconnected to control current flow paths, enabling the second transistor to replace the first transistor when defective. The welding pattern acts as a controllable switch that mediates the operational state without requiring direct modification of the transistor structures themselves
3Reliability
If the second transistor is used to replace the defective first transistor, then pixel functionality is restored, but luminance compensation is required
Solution Approach 1:
The luminance output of pixels using the second transistor is monitored and compared against reference pixels. Based on this feedback, compensation values are calculated and applied to adjust the driving voltages or emission parameters of the repaired pixels, ensuring their luminance matches that of non-repaired pixels and maintaining overall display uniformity
Data Source
AI summary
A display device having a repair structure that makes a defective pixel operate as a normal pixel in a display panel.