Capacitive Touch Panel With Segmented Pressure Electrodes
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Solution Overview
Problem
Conventional capacitive touch panels with cover members suffer from decreased pressure detection sensitivity due to the cover member preventing deformation and changes in capacitance between electrodes.
Innovation Solution
A capacitive touch panel design with alternately arranged pressure and position detecting electrodes, where the pressure detecting electrodes have larger areas and specific distance configurations to enhance sensitivity, and a cover member is used to maintain structural integrity while allowing increased pressure detection sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cover member is provided to protect the touch panel, then the structural integrity is improved, but the pressure detection sensitivity deteriorates
Solution Approach 1:
The pressure detecting electrode is divided into multiple pressure detecting sections arranged in the second direction, allowing independent detection from each section. This segmentation enables the system to maintain structural integrity with the cover member while achieving sufficient pressure detection sensitivity through combined signals from multiple sections.
Solution Approach 2:
The pressure detecting sections are positioned to overlap with drive electrodes in specific regions, creating local areas of enhanced capacitance coupling. This local quality optimization ensures that pressure detection sensitivity is maintained in critical areas despite the presence of the cover member.
2Manufacturing precision
If the distance between drive electrode and pressure sensing electrode is increased, then the manufacturing precision is improved, but the capacitance coupling deteriorates
Solution Approach 1:
Multiple pressure detecting sections are combined to form a single pressure detecting electrode, and their collective capacitance coupling with the drive electrode compensates for the reduced coupling strength due to increased distance. This merging allows greater manufacturing tolerance while maintaining overall detection sensitivity.
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 design improves pressure detection sensitivity by increasing the area of pressure detecting sections and optimizing electrode distances, reducing the impact of the cover member on capacitance changes and enhancing detection accuracy.
Implementation Method 1
a drive electrode 11a to which a drive signal is supplied
Implementation Method 2
the shortening of the distance between the drive electrode and the pressure sense electrode due to the pressing of the capacitive touch panel by the pointer causes an increase in capacitance between the drive electrode and the pressure sense electrode
Data Source
AI summary
A touch panel include a cover member, a drive electrode, a pressure detecting electrode, and a position detecting electrode. The pressure detecting electrode and the position detecting electrode are alternately arranged in a first direction. The pressure detecting electrode includes a plurality of pressure detecting sections, arranged side by side in a second direction orthogonal to the first direction, that each independently detect a pressure. The position detecting electrode includes a plurality of position detecting sections, arranged side by side in the second direction, that each independently detect a touched position. The area of a pressure detecting section is larger than the area of a position detecting section.