Microstructured Force Sensor for Low-Hysteresis Printed Sensing
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Solution Overview
Problem
Printed piezoresistive sensors face challenges with calibration difficulties, time drift, hysteresis, and resolution issues due to material deformation and lack of microstructures that can be manufactured at low cost and scaled for large production.
Innovation Solution
A force sensor with interdigital electrodes and microstructured conductive layers allows for easy calibration without applying a reference force, enhancing sensitivity, resolution, and reducing hysteresis through a parallel-mode configuration using printed materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If printed piezoresistive sensors are manufactured using conventional inks and printing processes, then manufacturing cost and scalability are improved, but measurement precision and material stability deteriorate due to plastic and viscoelastic deformation
Solution Approach 1:
The patent changes the material parameters by using elastomeric materials with predominantly elastic deformation behavior instead of plastic/viscoelastic materials. This parameter change maintains measurement precision while preserving the benefits of printed sensor manufacturing
Solution Approach 2:
The patent employs composite material structures including elastomeric materials combined with conductive fillers (such as carbon black, graphite, or metal particles) to create sensor materials that exhibit stable elastic deformation characteristics while maintaining electrical conductivity for measurement functions
2Measurement precision
If microstructures are implemented to improve sensitivity and reduce hysteresis, then measurement precision is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent segments the sensor structure into distinct functional layers including elastomeric substrate layers and conductive material layers. This segmentation allows each layer to be optimized independently for its specific function while maintaining overall measurement precision without excessive complexity
Solution Approach 2:
The patent applies local quality by implementing conductive material patterns specifically in regions where electrical measurement functions are needed, while other regions use pure elastomeric materials for mechanical deformation. This localized approach improves sensitivity where needed without increasing overall device complexity
3Ease of manufacture
If conventional printed sensor structures are used, then ease of manufacture is improved, but calibration difficulty increases due to infinitely large resistance in unloaded state
Solution Approach 1:
The patent extracts the calibration problem by introducing a separate reference resistance element that is mechanically decoupled from the measurement function. This reference resistance provides a stable baseline for calibration without being affected by the elastic deformation of the elastomeric material, enabling easy calibration while maintaining manufacturing simplicity
4Measurement precision
If elastomeric materials with elastic deformation are used, then measurement precision and material stability are improved, but device complexity increases compared to simple printed structures
Solution Approach 1:
The patent applies universality by designing the elastomeric material structure to simultaneously serve multiple functions: mechanical deformation sensing, electrical insulation, and structural support. This multi-functionality approach improves measurement precision without proportionally increasing device complexity, as the same material structure performs multiple roles
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 sensor provides reliable force measurement with improved sensitivity, resolution, and reduced hysteresis, enabling easy calibration and continuous operability testing, while maintaining a finite resistance in the unloaded state.
Implementation Method 1
The elastic substrates are compressed between the first and the second contact surfaces. The contact surfaces are defined as the surfaces of the two elastic substrates that are disposed opposite to each other.
Implementation Method 2
a first conductive layer, disposed on the first substrate and conductively connecting the first electrode and the second electrode with a first layer resistance
Data Source
AI summary
A force sensor (10) and a method for measuring a force are disclosed. The force sensor (10) comprises a first non-conductive substrate (1) and a second non-conductive substrate (4). A first electrode (2a) and a second electrode (2b) are disposed on the first substrate (1) and offset to each other. A first conductive layer (3) is disposed on the first substrate (1) and is conductively connecting the first electrode (2a) and the second electrode (2b) with a first layer resistance (R1). A second conductive layer (5) is disposed on the second substrate (4). The second conductive layer (5) is configured to conductively connect the first electrode (2a) and the second electrode (2b) via the second conductive layer (5) with a second layer resistance (R2) when the first non-conductive substrate (1) and the second non-conductive substrate (4) approach each other.