Capacitive Touch Panel Edge Detection Accuracy
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Solution Overview
Problem
Capacitive touch panels exhibit poor accuracy in coordinate detection at the edge regions compared to the intermediate regions due to the uniform pitch of detection electrodes.
Innovation Solution
The pitch of the endmost detection electrodes is reduced in the edge regions, allowing for improved coordinate detection accuracy by altering the electrode patterns, which includes changing the pitch and width of the endmost electrodes, and incorporating dummy electrodes to enhance sensitivity and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If detection electrodes are arranged at uniform pitch across the panel, then manufacturing is simplified and device complexity is reduced, but coordinate detection accuracy in edge regions deteriorates
Solution Approach 1:
The patent applies local quality by differentiating the pitch of detection electrodes based on their position. Edge region detection electrodes are arranged at a first pitch, while intermediate region detection electrodes are arranged at a second pitch (different from the first). This localized variation in electrode spacing optimizes coordinate detection accuracy in edge regions without compromising the simplicity of manufacturing, as the pitch differentiation follows a clear regional pattern that can be implemented through standard photolithography processes.
2Measurement precision
If endmost detection electrodes are arranged at smaller pitch, then coordinate detection accuracy in edge regions is improved, but device complexity increases due to non-uniform electrode patterns
Solution Approach 1:
The patent segments the detection electrode arrangement into distinct regions: edge regions with a first pitch and intermediate regions with a second pitch. This segmentation allows the system to optimize for edge detection accuracy by using a smaller pitch in edge regions while maintaining a larger pitch in intermediate regions. The segmentation is implemented through region-defining lines that divide the panel into edge and intermediate zones, enabling differentiated electrode spacing that improves overall measurement precision without creating excessive complexity.
Solution Approach 2:
The patent implements local quality by assigning different pitch values to different spatial locations on the panel. Specifically, detection electrodes in edge regions are spaced at a first pitch optimized for accurate coordinate detection near the panel boundaries, while detection electrodes in intermediate regions are spaced at a second pitch. This localized optimization ensures that each region's electrode arrangement is tailored to its specific detection requirements, improving coordinate detection accuracy in edge regions without uniformly increasing device complexity across the entire panel.
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
This approach enhances the accuracy of coordinate detection at the edge regions, ensuring precise touch input even near the panel edges without distortion, by adjusting the electrode patterns and sensitivity correction methods.
Implementation Method 1
A touch panel of a type in which a capacitance variation can be detected is, specifically, a touch panel configured to detect a variation in the capacitance between a pair of electrodes disposed with an insulating film in between
Data Source
AI summary
In a capacitive touch panel, edge regions of the panel display generally have poor accuracy of coordinate detection of a touch point as compared to the intermediate region of the panel display. A display device includes a plurality of first electrodes arranged at predetermined pitches and extending in a X-direction; and a plurality of second electrodes arranged at predetermined pitches and extending in a Y-direction, wherein both endmost first electrodes of the plurality of first electrodes have a smaller pitch than the other first electrodes, both endmost second electrodes of the plurality of second electrodes have a smaller pitch than the other second electrodes, and the display device is configured to detect a touch based on a capacitance variation at one or more of intersections of the plurality of first electrodes with the plurality of second electrodes.