Capacitance Touch Sensor Folded Electrode Slit Design
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Solution Overview
Problem
Pressure-sensitive touch sensors may erroneously detect touches on an operation surface, leading to incorrect recognition of operations.
Innovation Solution
A capacitance-type pressure-sensitive touch sensor module with a base material sheet, first and second electrodes, and an elastic layer, where the base material sheet is folded with a slit at the fold line to weaken the force trying to return to its original state, maintaining a stable distance between the electrodes and reducing erroneous detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the base material sheet is folded to bring electrodes closer for pressure detection, then the pressure-sensitive detection function is improved, but the folded part generates a strong restoring force that causes erroneous touch detection
Solution Approach 1:
The harmful restoring force generated by the folded base material sheet is extracted and removed by introducing a slit at the fold line portion. The slit allows the folded part to be separated into independent sections, preventing the generation of continuous restoring force across the entire folded structure, thereby eliminating the source of erroneous detection.
Solution Approach 2:
An elastic layer is introduced as an intermediary between the first and second electrodes. This elastic layer serves as a mediator that transmits the pressing force from the operation surface to the electrodes while maintaining stable electrode spacing. The elastic layer's properties allow it to deform under pressure without generating harmful restoring forces like the folded base material does.
2Measurement precision
If the distance between electrodes is reduced for better capacitance detection, then the sensitivity is improved, but the stability of electrode distance is compromised
Solution Approach 1:
The elastic layer acts as an intermediary that maintains stable spacing between the first and second electrodes. It provides a consistent mechanical interface that keeps electrodes at a fixed distance while still allowing controlled deformation under pressure, thus preserving both stability and sensitivity.
Solution Approach 2:
The elastic layer's physical properties (elastic modulus, thickness) are optimized to achieve the desired balance. By carefully selecting these parameters, the system achieves sufficient electrode proximity for sensitive capacitance detection while maintaining adequate distance stability through the elastic layer's restoring characteristics.
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 solution effectively reduces erroneous detection of touches on the operation surface, enhancing the accuracy of capacitance change detection and improving the reliability of operation recognition.
Implementation Method 1
the elastic layer is compressed and deformed in a thickness direction by a pressing force to reduce a distance between the first electrode and the second electrode
Implementation Method 2
The pressing on the operation surface is detected based on a change in capacitance, which is caused when the elastic layer is compressed and deformed
Data Source
AI summary
In a pressure-sensitive touch sensor of a capacitance type, a first electrode and a second electrode are provided on a first surface of a base material sheet. The base material sheet is folded between the first electrode and the second electrode so that a surface of the first electrode and a surface of the second electrode face each other. The base material sheet is folded at a fold line portion in which a slit is formed. An elastic layer is provided between folded parts of the base material sheet. The pressure-sensitive touch sensor is configured to detect pressing on the operation surface based on a change in capacitance, which is caused when the elastic layer is compressed and deformed in a thickness direction by a pressing force to reduce a distance between the first electrode and the second electrode.