Grooved On-Cell Touch Panel for Stable Folding Capacitance
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Solution Overview
Problem
Touch electrodes in flexible display devices experience deformation-related issues such as resistance and capacitance changes, disconnection, and unstable touch performance during stretching, rolling, and folding, limiting the deformation amount and accuracy of touch position judgment.
Innovation Solution
A touch panel design with insulated first and second touch electrodes on a substrate, featuring grooves that prevent overlap with electrode projections, and an encapsulation layer and buffer layer in the grooves, along with a bridge connection between adjacent electrodes, to manage deformation and maintain capacitance stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If touch electrodes are disposed on an upper glass substrate of display panel (on-cell touch), then small RC delay and no shading are achieved, but the touch electrodes are deformed during flexible deformation leading to unstable touch performance
Solution Approach 1:
The touch electrode pattern is segmented into multiple isolated conductive regions (first touch electrode regions and second touch electrode regions) that are electrically insulated from each other. This segmentation prevents continuous deformation propagation and maintains touch performance stability during flexible deformation while preserving the on-cell touch advantages of small RC delay and no shading.
Solution Approach 2:
Different regions of the touch panel are assigned different electrical properties through the insulating layer configuration. The first touch electrode regions and second touch electrode regions are locally differentiated and insulated from each other, creating localized electrical zones that maintain stable capacitance characteristics during deformation.
2Reliability
If touch electrodes are made continuous for good electrical connection, then electrical conductivity is improved, but the electrodes may be partially disconnected after repeated deformation
Solution Approach 1:
The continuous touch electrode structure is divided into multiple segmented conductive regions separated by insulating layers. This segmentation prevents crack propagation and partial disconnection during repeated deformation while maintaining reliable electrical connections within each segmented region.
Solution Approach 2:
The insulating layer is pre-configured between adjacent touch electrode regions to provide mechanical cushioning and electrical insulation before deformation occurs. This preventive measure protects against electrode disconnection and maintains electrical connection stability during flexible deformation.
3Adaptability or versatility
If the touch panel allows large deformation for flexibility, then adaptability is improved, but resistance and capacitance of the touch electrode change significantly
Solution Approach 1:
The touch electrode system is segmented into multiple insulated regions that can independently accommodate deformation. This segmentation allows the touch panel to achieve large deformation for flexibility while maintaining stable resistance and capacitance values in each segmented region, preserving touch position judgment accuracy.
Solution Approach 2:
The insulating layer configuration enables the touch electrode structure to adapt its electrical parameters (resistance and capacitance) locally in response to deformation, allowing the touch panel to maintain stable electrical characteristics across different deformation states.
Data Source
AI summary
A touch panel, a preparation method therefor, and a display device. The touch panel comprises a substrate, a plurality of spaced apart first touch electrodes and a plurality of spaced apart second touch electrodes that are arranged on the same layer on the substrate. The first touch electrodes and the second touch electrodes are insulated from each other. The substrate is also provided with a plurality of grooves, and the orthographic projection of the first touch electrodes and the second touch electrodes on the substrate do not overlap with the orthographic projection of the grooves in the substrate.