Touch Substrate Corner Lead Structure for Bend Crack Prevention
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Solution Overview
Problem
The challenge of cracking in touch signal wires at the corners of flexible touch display screens due to large-angle cover plate attachment, which reduces yield and increases production costs.
Innovation Solution
A touch substrate design with corner leads located entirely in the bending region and first lead portions extending from the bending region to the flat region, avoiding overlap with the bending boundary, and incorporating a stacked lead layer structure with via holes to relieve stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If corner leads are positioned at corners of the touch substrate to provide signals for touch electrodes, then signal transmission is enabled, but the leads overlap with the bending boundary causing cracking during large-angle cover plate attachment
Solution Approach 1:
The patent extracts the corner lead from the bending boundary region and relocates it entirely within the flat region. This separation removes the lead from the harmful bending stress zone, preventing cracking while maintaining signal transmission functionality to the touch electrodes.
Solution Approach 2:
The patent changes the spatial arrangement of the corner lead by extending it along the second edge direction rather than positioning it at the corner intersection. This dimensional repositioning moves the lead away from the bending boundary into the flat region, eliminating stress concentration while preserving electrical connection.
2Adaptability or versatility
If the touch substrate is designed with bending regions for flexible display, then flexibility and narrow bezel are achieved, but touch leads crossing the bending boundary experience cracking during assembly
Solution Approach 1:
The patent applies different spatial zones with different functional qualities: the flat region accommodates leads requiring mechanical stability, while the bending region is reserved for flexibility without leads. This local differentiation ensures leads remain in stable zones while the substrate maintains flexibility through controlled bending in lead-free zones.
3Productivity
If corner leads are positioned to enable signal transmission for touch electrodes, then touch functionality is achieved, but production yield decreases due to cracking during cover plate attachment
Solution Approach 1:
By extracting the corner lead from the bending boundary region and relocating it to the flat region, the patent eliminates the source of cracking during cover plate attachment. This prevents assembly failures and improves production yield while maintaining touch signal transmission functionality.
Data Source
AI summary
A touch substrate includes multiple touch electrodes and multiple touch leads, and has a touch region and a non-touch region. The touch electrodes are located in the touch region, and the touch leads are located in the non-touch region and provide signals for the touch electrodes. The touch substrate is divided into a flat region and a bending region(s) by a bending boundary. The touch substrate includes: a first side, a second side and a corner between the first side and the second side. The bending boundary substantially extends in the extension direction of the first edge and intersects with the second edge. A touch lead includes: a corner lead, an end of the corner lead is connected with a first lead portion, and the corner lead is completely located in the bending region and does not overlap with the bending boundary.