Guard Electrode Force Sensor Layout for Crosstalk Reduction
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Solution Overview
Problem
Force sensors with a sensor layer on the array substrate experience crosstalk due to current flow in the plane parallel to the sensor layer, which is not ideal for dynamic range considerations.
Innovation Solution
The force sensor incorporates a guard electrode on the array substrate and a conductive elastomer sensor layer, with the guard electrode and array electrodes maintained at equipotential, preventing current flow between adjacent electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a sensor layer made of conductive elastomer is provided on the array electrode, then the manufacturing process is simplified and bonding accuracy is improved, but current flows in the direction parallel to the sensor layer causing crosstalk
Solution Approach 1:
A guard electrode is introduced as an intermediary element between the array electrodes. This guard electrode acts as a mediator that captures and redirects stray current paths, preventing direct crosstalk between adjacent array electrodes while maintaining the beneficial conductive elastomer sensor layer configuration.
Solution Approach 2:
The guard electrode is maintained at the same potential as the array electrodes through proper electrical connection. This equipotential configuration eliminates potential differences that would drive crosstalk current, while still allowing the conductive elastomer to function effectively for force sensing.
2Object-generated harmful factors
If an anisotropic conductive film is used as the sensor layer to prevent crosstalk, then current flow is restricted to the thickness direction, but the dynamic range is compromised
Solution Approach 1:
The guard electrode serves as a mediator that enables the use of isotropic conductive elastomer material while achieving crosstalk prevention. By providing an intermediate electrical pathway, the system gains both the dynamic range benefits of elastomer and the crosstalk prevention normally requiring anisotropic materials.
Solution Approach 2:
The electrical parameters of the sensor system are modified by introducing the guard electrode configuration. This changes the current distribution pattern without altering the fundamental properties of the conductive elastomer, allowing isotropic materials to achieve anisotropic-like crosstalk prevention performance.
3Measurement precision
If the sensor layer is separated from the array substrate when no force is input, then the sensor layer contacts the array electrodes only when force is applied, but this configuration does not prevent crosstalk when the sensor layer is on the array electrode
Solution Approach 1:
The guard electrode acts as an intermediary that prevents crosstalk even when the sensor layer is in continuous contact with the array electrodes. By providing a controlled electrical pathway, it eliminates harmful current leakage between adjacent electrodes while maintaining the sensor's measurement precision.
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 configuration effectively reduces crosstalk by ensuring current flows only through the intended electrode, maintaining accurate signal detection and enhancing dynamic range.
Implementation Method 1
The electric resistance of the conductive elastomer decreases when the conductive elastomer deforms
Implementation Method 2
a guard electrode disposed on the first surface and extending between the array electrodes... The array substrate and the guard electrode are equipotential
Data Source
AI summary
A force sensor includes an array substrate having a first surface provided with a plurality of array electrodes, a counter substrate having an opposite surface facing the first surface, a guard electrode disposed on the first surface and extending between the array electrodes, a sensor layer made of a conductive elastomer and placed over the first surface, the array electrodes, and the guard electrode, and a common electrode provided on the opposite surface. The array substrate and the guard electrode are equipotential.