Conductive Repairing Pattern Layers for Capacitive Touch Panel Defect Resolution
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Solution Overview
Problem
Capacitive touch display panels, especially the integrated/in-cell type, face low yield rates due to electrostatic discharge damage to touch-control circuits during fabrication and use, leading to short or open defects in metal bridge lines at crossover regions, which are difficult to repair effectively.
Innovation Solution
A touch panel design incorporating conductive repairing pattern layers that are electrically floating and overlapped with adjacent sensing pads, allowing for repair of defects through methods like laser cutting and welding, ensuring normal sensing operation by reconnecting isolated sensing pads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal bridge lines are used to couple adjacent sensing pads in the crossover region, then the sensing series can avoid short circuits, but the metal bridge lines can be burned by electrostatic discharge causing short or open defects
Solution Approach 1:
The patent introduces a conductive repairing pattern layer as an intermediary component positioned between the metal bridge lines and the sensing pads. This repairing pattern layer serves as a protective mediator that can be damaged instead of the critical sensing pads, allowing for selective replacement while preserving the original metal bridge line structure and sensing pad integrity.
Solution Approach 2:
The conductive repairing pattern layer is pre-formed on the substrate before the metal bridge lines and sensing pads are created. This preliminary positioning of the repairing pattern layer allows it to serve as a sacrificial protective element that can be damaged by electrostatic discharge without affecting the underlying sensing series, enabling subsequent selective removal and replacement.
2Reliability
If electrostatic discharge occurs during fabrication or use, then the touch-control circuit may be damaged, but the damage is difficult to repair effectively
Solution Approach 1:
The conductive repairing pattern layer acts as a sacrificial intermediary that absorbs electrostatic discharge damage. When ESD occurs, the repairing pattern layer is damaged instead of the critical sensing pads or metal bridge lines. This allows the system to be repaired by selectively removing the damaged repairing pattern layer and replacing it, while preserving the integrity of the underlying sensing series.
Solution Approach 2:
The patent segments the protective function from the critical sensing functionality by separating the conductive repairing pattern layer from the metal bridge lines and sensing pads. This segmentation allows independent replacement of the repairing pattern layer without affecting the sensing series, simplifying the repair process and improving repair effectiveness.
3Ease of manufacture
If the integrated/in-cell type touch display panel is fabricated by forming touch-control circuit first then color filter thin film, then the panel can be manufactured, but the touch-control circuit is often damaged due to electrostatic discharge during color filter thin film formation
Solution Approach 1:
The conductive repairing pattern layer is formed on the substrate before the touch-control circuit and color filter thin film are created. This preliminary formation of the repairing pattern layer provides protective coverage to the sensing pads during the subsequent fabrication process, including the color filter thin film formation step where electrostatic discharge most commonly occurs.
Solution Approach 2:
The conductive repairing pattern layer serves as a sacrificial protective layer that is positioned beforehand to cushion against electrostatic discharge during fabrication. When ESD occurs during color filter thin film formation, the repairing pattern layer absorbs the damage instead of the touch-control circuit, enabling the panel to continue manufacturing or be easily repaired.
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 solution significantly improves the yield and simplifies the repair process for capacitive touch panels, particularly for integrated/in-cell type panels, by enabling effective repair of defects caused by electrostatic discharge, reducing waste and production costs.
Implementation Method 1
Each of the conductive repairing pattern layers is overlapped with two adjacent first sensing pads in the same first sensing series, and each conductive repairing pattern layer locates around the crossover region of the first sensing series and the second sensing series. The conductive repairing pattern layers are electrically floating, and can connect the two adjacent sensing pads after the repair procedure is finished.
Data Source
AI summary
A touch panel including a substrate, a plurality of first and second sensing series, and a plurality of conductive repairing pattern layers is provided. The first sensing series are disposed on the substrate and extended along a first direction. Each of the first sensing series includes a plurality of first sensing pads and first bridge lines, and the first bridge lines serially connect two adjacent first sensing pads. The second sensing series are disposed on the substrate and extended along a second direction. Each of the second sensing series includes a plurality of second sensing pads and second bridge lines, and the second bridge lines serially connect two adjacent second sensing pads. Each conductive repairing pattern layer electrically floating locates around the crossover region of the first and second sensing series. Two adjacent sensing pads are connected by the conductive repairing pattern layer after a repair procedure is finished.