Touch Sensor Driving Electrode Segmentation for Bezel Reduction
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Solution Overview
Problem
Touch sensors face challenges in reducing the size of the non-display area, known as the bezel, which increases with the number of receiving channels, leading to higher wiring resistance and deteriorated electrical characteristics, limiting the ability to minimize the bezel width and improve touch sensitivity and recognition time.
Innovation Solution
The touch sensor design includes driving electrodes with at least two divided areas connected to separate driving channels and receiving electrodes with unit patterns connected to separate receiving channels, with careful wiring arrangements to minimize channel crossings and reduce the number of channels, allowing for reduced bezel width and improved sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the number of receiving channels is increased to sense touch positions over the entire area, then the touch sensing coverage is improved, but the size of the non-display area (bezel) is increased
Solution Approach 1:
The touch sensor is divided into multiple divided areas, with driving electrodes and receiving electrodes arranged in a grid pattern across these areas. This segmentation allows comprehensive touch sensing coverage while organizing the electrode structure to minimize wiring requirements and reduce bezel width.
2Length of stationary object
If the wiring width of the wiring lines is reduced to decrease the non-display area, then the bezel width is reduced, but the wiring resistance is increased and electrical characteristics are deteriorated
Solution Approach 1:
The electrode patterns are designed with extended structures that span multiple divided areas, allowing wiring to be distributed more efficiently across the sensor surface. This dimensional arrangement reduces the total wiring length required in the bezel area while maintaining adequate wire width for acceptable resistance levels.
3Measurement precision
If the number of channels is increased to improve touch sensing precision, then the touch position detection accuracy is improved, but the device complexity is increased
Solution Approach 1:
Adjacent receiving electrodes in different divided areas are connected to the same receiving channel, merging their sensing functions. This reduces the total number of channels required while maintaining comprehensive touch position detection capability across the entire sensor area through coordinate mapping.
4Reliability
If the wiring lines are arranged to connect all electrodes to separate channels, then the electrical characteristics are maintained, but the non-display area size is increased
Solution Approach 1:
Multiple receiving electrodes serve the same receiving channel, making the channel universal for detecting touches across different divided areas. This multi-functional arrangement reduces the total number of channels and wiring lines required, thereby reducing the non-display area while maintaining electrical performance.
Data Source
AI summary
A touch sensor includes a driving electrode which includes at least two divided areas electrically separated from each other, wherein each divided area includes first patterns connected to each other in a first direction and second patterns extending from the first pattern in a second direction, and a receiving electrode which is formed on the same plane as the driving electrode in the second direction, wherein the driving electrodes are respectively connected to separate driving channels by driving electrode wirings for each divided area, such that it is possible to sense touch positions over the entire area only by a smaller number of channels. Thereby, it is possible to significantly reduce the bezel width, and may maintain excellent touch sensitivity while significantly shortening the touch recognition time.