Stretchable Pressure Sensor with Gas Pocket for Textile Integration
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Solution Overview
Problem
Existing pressure sensors, particularly force sensing resistors (FSR), face challenges such as complex wiring schemes, high manufacturing costs, and reduced sensitivity due to non-uniform force-resistance relations, making them difficult to integrate into textile products while maintaining long-term repeatability and comfort.
Innovation Solution
A pressure sensor design featuring stretchable carriers with adjacent electrically conductive leads and a resistive layer, forming a pocket structure with a gas confining structure that counteracts force, utilizing microstructured bumps for pressure distribution and a thermoplastic polymer for flexibility and comfort, allowing for integration into textiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a gas confining structure is introduced to counteract applied force, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent applies pneumatic principles by introducing a gas confining structure (pocket) between the first and second carriers that traps and compresses gas to counteract the applied force. This pneumatic counterforce mechanism improves measurement precision by compensating for force applied to the sensor, while the gas pocket integrates seamlessly into the existing carrier structure rather than adding external components.
Solution Approach 2:
The gas confining structure is nested within the space between the first and second carriers, utilizing the existing structural volume. The pocket structure is formed by the carriers themselves and optional spacers, integrating the gas containment function into the existing sensor architecture rather than adding separate external components.
2Measurement precision
If carriers are made stretchable to reduce separation distance, then sensitivity is improved, but manufacturing precision becomes more difficult to maintain
Solution Approach 1:
The patent changes the mechanical parameter of the carriers from rigid to stretchable/elastomeric. This allows the carriers to dynamically adjust their separation distance in response to applied pressure, improving sensitivity. The stretchable nature accommodates manufacturing tolerances by allowing elastic deformation that brings the carriers into proper contact under operating conditions.
Solution Approach 2:
The carriers are constructed from composite or elastomeric materials that combine structural integrity with stretchability. This allows the carriers to maintain their shape and alignment during manufacturing while being capable of elastic deformation during operation to achieve the desired separation distance reduction and sensitivity.
3Reliability
If microstructured bumps are added for pressure distribution, then reliability is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies microstructured bumps only to specific contact surfaces of the carriers where pressure distribution is needed. This localized application improves reliability by ensuring uniform pressure distribution at critical interfaces, while the rest of the carrier surfaces remain simple and easy to manufacture. The bumps are typically applied only to the surfaces that directly contact or face each other across the gap.
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 provides improved sensitivity, comfort, and long-term repeatability by reducing the separation distance between carriers, compressing gas to counteract force, and using thermoplastic polymers for flexible integration into textiles, enhancing the sensor's performance and manufacturing feasibility.
Implementation Method 1
a gas confining structure that is filled with a gas that at least partly counters a force (F) exerted on the pressure sensor
Implementation Method 2
an electrically resistive layer formed of a composite material for shunting the at least two adjacent electrically conductive leads... results in a pressure dependent electrical resistance between the conductive leads
Implementation Method 3
The stretchable first carrier and the stretchable second carrier... upon receiving the force (F), exerted in a direction across the gap, the gap is reduced between the electrically resistive layer and the at least two adjacent electrically conductive leads
Data Source
AI summary
The present disclosure concerns a pressure sensor, comprising at least two adjacent electrically conductive leads disposed in a pattern on a face of a first elastomeric carrier; and an electrically resistive layer formed of a electrically resistive composite material for shunting the at least two adjacent electrically conductive leads, said electrically conducting layer disposed on a face of a second elastomeric carrier. The first and second carriers are stacked across a spacer such that the at least two adjacent electrically conductive leads faces the electrically resistive layer across a gap defined by the spacer. The gap is formed by a pocket between the carriers. The first carrier including the at least two adjacent electrically conductive leads and/or the second carrier including the electrically resistive layer are stretchable such as to upon receiving a force, exerted in a direction across the gap, reduce the gap between the electrically resistive layer and the at least two adjacent electrically conductive leads. Upon closing the gap the adjacent electrically conductive leads are shunted over a force dependent contact area and contact resistance. A gas in a gas confining structure between the carriers at least partly counteracts the exerted force.