Capacitive Sensor Array with Integrated Diode Temperature Sensing
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Solution Overview
Problem
Existing capacitive sensor arrays are limited in their ability to measure all six components of forces and moments, and they lack integrated temperature sensing capabilities, which are essential for comprehensive force and moment analysis.
Innovation Solution
The integration of silicon diodes as temperature sensors into the capacitive sensor array, allowing for simultaneous force and temperature sensing without additional signal traces, using a multiplexer to select between electrical pulses and currents for delivery to the drive plates, and circuitry to differentiate between force and temperature measurements using the same input amplifier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If capacitive sensor arrays are configured to measure all six components of forces and moments, then measurement capability is improved, but device complexity increases due to requiring at least 10 separate electrically conductive nodes
Solution Approach 1:
The patent combines force sensing and temperature sensing into a single integrated sensor array structure. Temperature sensors (thermistors or diodes) are embedded within the dielectric layer between drive plates and sense plates, allowing both force and temperature measurements to be obtained from the same physical structure without requiring separate sensor systems.
Solution Approach 2:
The sensor array is designed to perform multiple functions: measuring all six components of forces and moments through capacitance changes, while simultaneously measuring temperature through embedded temperature sensors. This multi-functional design allows a single device to provide comprehensive environmental and mechanical data.
2Adaptability or versatility
If temperature sensors are added to capacitive sensor arrays, then temperature measurement capability is improved, but device complexity increases due to requiring additional signal traces
Solution Approach 1:
The temperature sensing elements are embedded within the dielectric layer of the capacitive sensor structure, merging temperature sensing functionality into the existing force sensing architecture. This integration allows temperature measurement without adding separate signal traces outside the existing capacitor structure.
Solution Approach 2:
Temperature sensors (thermistors or diodes) are nested within the dielectric layer between the drive plates and sense plates. This nesting approach places the temperature sensors inside the existing sensor structure, utilizing the same physical space and signal paths rather than requiring additional external components and traces.
3Measurement precision
If multiple electrodes are used to measure all force components, then measurement precision is improved, but manufacturing complexity increases
Solution Approach 1:
The sensor plates are divided into multiple segments or zones, with each segment capable of detecting specific force components. This segmentation allows precise measurement of all six force and moment components while maintaining a regular, manufacturable plate structure that can be produced using standard fabrication techniques.
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
Enables the accurate measurement of both axial and shear forces, as well as temperature changes, with increased spatial sensitivity and reduced error from sneak current paths, facilitating early warning systems for diabetic foot ulcers and other applications.
Implementation Method 1
A diode with a forward junction voltage is connected between at least one of the drive plates and at least one of the sense plates. Circuitry is provided for sensing a temperature resulting from a change in the forward junction voltage of the diode when the current is delivered.
Implementation Method 2
The sensor includes an array of drive plates, an array of sense plates corresponding the drive plates, and a layer of dielectric material separating the drive plates and the sense plates. Circuitry is provided for sensing an applied force resulting from a change in capacitance between the at least one drive plate and the at least one sense plate.
Implementation Method 3
A multiplexer is operative to select between an electrical pulse or an electrical current for delivery to the at least one drive plate.
Data Source
AI summary
A combined force- and temperature-sensing array includes an array of drive plates, an array of sense plates corresponding the drive plates, and a layer of dielectric material separating the drive and sense plates. A diode with a forward junction voltage is connected between at least one of the drive plates and at least one of the sense plates. A multiplexer is operative to select between an electrical pulse or an electrical current for delivery to the at least one drive plate. Circuitry is provided for sensing an applied force resulting from a change in capacitance between the at least one drive plate and the at least one sense plate when the electrical pulse is delivered, and for sensing a temperature resulting from a change in the forward junction voltage of the diode when the current is delivered. The sensor array may be provided as a shoe insert for diabetics with neuropathy.