Foil Force Sensor Layout for Thin Flexible Static Load Detection
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Solution Overview
Problem
Existing force sensors face challenges in miniaturization and flexibility, with issues related to precise calibration and resilience against environmental factors such as temperature and humidity.
Innovation Solution
A foil sensor with a direct force transducer and conductive electrode traces on a polymer foil, partially covered by a polymer nanocomposite, allowing for elastic deformation and impedance/resistance measurement to detect forces, adaptable to various applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional force sensors are miniaturized, then the sensor size is reduced, but the installation height cannot be sufficiently reduced and flexibility is limited
Solution Approach 1:
The patent uses a polymer foil as the base substrate with conductive electrode traces printed directly on it, creating a flexible, thin-film sensor structure. This approach eliminates rigid housing and allows the sensor to conform to curved surfaces, significantly reducing installation height while maintaining structural integrity and force detection capability.
2Measurement precision
If strain gauge sensors are used, then high sensitivity and good linearity are achieved, but temperature dependence and calibration requirements increase device complexity
Solution Approach 1:
The patent combines the force sensing element (polymer foil with electrode traces) and the measurement element (electrode traces) into a single integrated structure. The conductive traces serve dual purposes as both structural components and sensing elements, eliminating the need for separate strain gauges and reducing calibration complexity while maintaining high sensitivity through direct resistance change measurement.
3Speed
If piezoelectric sensors are used, then high sensitivity and fast response time are achieved, but suitability for static force measurements decreases
Solution Approach 1:
The patent employs a polymer foil with conductive electrode traces where the electrical resistance changes in response to applied force. This resistive sensing mechanism works effectively for both dynamic and static force measurements, providing fast response times for dynamic applications while maintaining stable readings for static forces, thus achieving versatility across different measurement scenarios.
4Measurement precision
If capacitive sensors are used, then high accuracy and low hysteresis are achieved, but sensitivity to environmental influences increases
Solution Approach 1:
The patent uses a simple polymer foil with printed conductive traces that is inherently robust against environmental factors. The polymer material and conductive inks are chosen for their stability against humidity and temperature variations, creating a sensor that maintains accurate measurements in diverse environmental conditions without requiring complex protection or calibration systems.
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 flexible force detection with reduced installation height, high sensitivity, and adaptability to different sensory applications through elastic deformation and electrical resistance changes.
Implementation Method 1
The direct force sensor (21) detects the mechanical forces acting on the surface and deforms elastically under the influence of force
Implementation Method 2
This compression change of the polymer nanocomposite results in a change in the electric field and/or the electrical resistance implied by the conductive electrode traces
Data Source
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AI summary
The present invention relates to a foil force detection sensor with a direct force transducer, comprising a corresponding electrical contact line for detecting forces and force loads, wherein an electrical signal can be derived from the foil force detection sensor with direct force transducer. At least two conductive electrodes (12) are applied to the plastic foil material (11), which have a contact area (13) on the connecting leads. A direct force transducer (21) is applied to this surface of the plastic foil material (11) facing the conductive electrodes (12), which detects the mechanical forces acting on the surface and deforms elastically under the influence of force. The direct force transducer (21) does not cover the conductive electrodes (12) or only partially covers them, and furthermore, the direct force transducer (21) does not cover the contact area (13).A polymer nanocomposite material (31) is also applied to this surface of the plastic film material (11) facing the conductive electrodes (12), in particular such that the conductive electrodes (12) are completely or predominantly covered by the polymer nanocomposite material (31). The polymer nanocomposite material (31) does not touch the direct force sensor (21) or only partially, thus creating a free space (32) between the polymer nanocomposite material (31) and the direct force sensor (21). The elastic material compression of the polymer nanocomposite material (31) can be detected by means of an impedance and/or electrical resistance measurement across the conductive electrodes (12).