Cover Electrode Overlap Width for Laser Repair Margin
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Solution Overview
Problem
The success rate of repairs in liquid display apparatuses is decreased due to short circuits occurring when drain-neck-cutting is performed in areas with cover electrodes, leading to inefficiencies in manufacturing and quality issues.
Innovation Solution
A display substrate design with a cover electrode that overlaps the gate line by a specific width, ensuring enough margin for laser repair and reducing the likelihood of short circuits, includes a capping layer and organic layer configurations that enhance repair success rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If drain-neck-cutting is performed in an area with cover electrode, then repair can be attempted, but short circuit between data line and cover electrode occurs
Solution Approach 1:
The patent extracts the cover electrode from directly over the data line area by positioning it only over the pixel electrode region. This separation removes the interfering element (cover electrode) from the repair zone, allowing laser cutting to proceed without creating short circuits while maintaining the cover electrode's protective function over the pixel electrode.
Solution Approach 2:
The patent applies different spatial configurations to different electrodes: the cover electrode is positioned to overlap the pixel electrode for protection, but deliberately does not overlap the data line area. This local differentiation allows the same cover electrode structure to provide protection where needed while avoiding interference with repair operations in the data line region.
2Ease of repair
If cover electrode overlaps gate line by specific width, then margin for laser repair is ensured, but device structure becomes more constrained
Solution Approach 1:
The patent performs preliminary positioning of the cover electrode during the manufacturing process, establishing a fixed overlap width with the gate line before repair operations are needed. This advance configuration ensures adequate margin for laser repair without requiring complex adjustments during the repair process itself.
Solution Approach 2:
The patent specifies a particular overlap width parameter between the cover electrode and gate line to optimize repair margins. By controlling this geometric parameter within a specific range, the design balances repair accessibility with manufacturing feasibility, transforming a qualitative design challenge into a quantifiable parameter specification.
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
The design increases the success rate of repairs and improves the quality of display apparatuses by providing sufficient margins for laser repair and minimizing short circuits, thus reducing failure rates.
Implementation Method 1
a laser repair is used to disconnect a wiring. Particularly, a failure due to a short of a gate line and a data line is occurred, a drain-neck-cutting is used as a method of repair. The drain-neck-cutting is performed by cutting a line extending from the data line to a transistor by a laser.
Data Source
AI summary
A display substrate includes a first switching element, an organic layer disposed on the first switching element, a capping layer disposed on the organic layer and a cover electrode covering the first emission hole. The first switching element is electrically connected to a gate line extending in a first direction, a data line extending in a second direction crossing the first direction and the pixel electrode disposed adjacent to the data line. The capping layer includes a first emission hole. The cover electrode overlaps the gate line as a first width. The cover electrode overlaps the first switching element as a second width. The second width is smaller than the first width.