OLED Display Substrate Repair Electrode for Bright Spot Defects
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for repairing defective bright spots in OLED display substrates, particularly top emission type, have low success rates due to the overlap of light-emitting and driving circuit regions, making it difficult to weld or cut power lines without damaging the circuit.
Innovation Solution
A display substrate design with a pre-arranged repair electrode that connects the drain electrode of the driving transistor with the auxiliary cathode line, allowing for short-circuiting of the anode and cathode of the light-emitting structure layer using laser irradiation, effectively repairing bright spots without damaging the pixel driving circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional repair methods (welding or cutting power lines) are used to repair defective bright spots, then the bright spot defect can be addressed, but the pixel driving circuit is damaged due to the overlap of light-emitting and driving circuit regions
Solution Approach 1:
The patent segments the repair function from the main circuit by introducing a dedicated repair electrode that is spatially separated from the driving transistor. The repair electrode is positioned in the light-emitting region and connected to the auxiliary cathode line, allowing independent repair operations without affecting the driving circuit. This segmentation enables the repair process to target only the defective light-emitting structure while leaving the driving circuit intact.
Solution Approach 2:
The patent introduces an auxiliary cathode line as an intermediary element that facilitates repair operations. The auxiliary cathode line is specifically designed to connect with the repair electrode and provide a safe pathway for current during repair, acting as a mediator between the repair electrode and the cathode of the light-emitting structure. This intermediary structure enables defect repair without requiring direct modification of the driving circuit.
2Productivity
If the light-emitting region overlaps with the driving circuit to achieve high aperture ratio, then the aperture ratio is improved, but the difficulty of repairing defective bright spots increases
Solution Approach 1:
The patent resolves the spatial conflict by transitioning to a multi-dimensional structure. The repair electrode is placed in a different layer (light-emitting region) than the driving circuit, utilizing the vertical dimension to separate repair functions from driving functions. The auxiliary cathode line provides vertical connectivity between these layers, enabling repair access from the light-emitting region without interfering with the horizontally arranged driving circuit.
Solution Approach 2:
The patent incorporates the auxiliary cathode line and repair electrode into the initial substrate structure during manufacturing. These repair components are pre-positioned and connected to appropriate circuit nodes before any defects occur. This preliminary arrangement ensures that when bright spot defects arise, the repair infrastructure is already in place and accessible, eliminating the need for complex circuit modifications during repair operations.
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 achieves a high repair success rate for top emission type OLED substrates, preventing product scrapping and improving yield, while maintaining the integrity of the pixel driving circuit.
Implementation Method 1
irradiating the first overlapping region and the second overlapping region with laser from a side of the substrate far away from the driving circuit layer, welding and connecting the repair electrode with the drain electrode of the driving transistor
Implementation Method 2
irradiating the first overlapping region and the second overlapping region with laser from a side of the substrate far away from the driving circuit layer, welding and connecting the repair electrode with the auxiliary cathode line
Data Source
AI summary
A display substrate, a preparation method and a repair method thereof, and a display apparatus. The display substrate includes a driver circuit layer and an emissive structure layer overlappingly disposed on a base, the driver circuit layer including a drive transistor, an auxiliary cathode wire and a repair electrode, an anode of the emissive structure layer being connected to a drain electrode of the drive transistor, a cathode of the emissive structure layer being connected to the auxiliary cathode wire, and the repair electrode being configured so as to connect the drain electrode of the drive transistor and the auxiliary cathode wire when repairing a bright spot defect.