Capacitive Pressure Sensor Elastic Layers for Low Hysteresis
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Solution Overview
Problem
Capacitive pressure-sensitive sensors using soft elastic materials with low resilience and high hysteresis loss ratios, which cause prolonged recovery periods and are not adequately addressed by existing technologies.
Innovation Solution
A capacitive pressure-sensitive sensor design incorporating two types of elastic layers with different stress characteristics, specifically a first and second elastic layer with a stress difference of 3 kPa or more, to control hysteresis loss and facilitate faster recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a soft elastic material with small Young's modulus is used as a dielectric elastic material, then the sensitivity of the capacitive pressure-sensitive sensor is improved, but the hysteresis loss ratio increases and resilience decreases
Solution Approach 1:
The patent uses a composite structure with two different elastic materials (first elastic material and second elastic material with different physical properties) to create the elastic layers. This composite approach allows combining the high sensitivity of soft materials with the low hysteresis characteristics of other elastic materials, resolving the contradiction between sensitivity and hysteresis loss.
Solution Approach 2:
The patent applies different elastic materials to different layers (first elastic layer and second elastic layer with different configurations). By optimizing the physical properties of each layer locally, the sensor achieves both high sensitivity in the detection region and low hysteresis in the supporting structure, preventing the uniform material limitation.
2Measurement precision
If a soft elastic material is used as a dielectric elastic material, then the sensitivity of the capacitive pressure-sensitive sensor is improved, but the recovery period is prolonged
Solution Approach 1:
The patent employs a composite elastic structure where the second elastic material has different physical properties from the first elastic material. This composite design enables the sensor to maintain high sensitivity while achieving faster recovery by selecting materials with appropriate elastic recovery characteristics.
Solution Approach 2:
The patent changes the physical parameters of the elastic materials used in different layers. By selecting materials with different Young's moduli, density, and elastic recovery rates for the first and second elastic layers, the sensor achieves both high sensitivity and short recovery period through parameter optimization.
3Adaptability or versatility
If the Young's modulus of the second dielectric layer is made larger than that of the first dielectric layer, then a wide dynamic range of measurable loads is realized, but the hysteresis loss ratio problem is not solved
Solution Approach 1:
The patent uses composite elastic materials in the elastic layers rather than relying solely on dielectric layers with different Young's moduli. The combination of first and second elastic materials with different physical properties directly addresses both the dynamic range requirement and the hysteresis loss problem in the elastic deformation region.
Solution Approach 2:
The patent optimizes the physical properties of different elastic layers locally. The first elastic layer and second elastic layer have different configurations and material properties tailored to specific functions: one optimized for sensitivity, the other for reducing hysteresis and enabling wide dynamic range measurement.
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 achieves reduced hysteresis loss ratios and shorter recovery periods, making it suitable for repeated measurements by controlling stress differences between elastic layers.
Implementation Method 1
when a compressive force acts on the sensor, a dielectric elastic material is compressed, and the capacitance increases between electrodes separated by the dielectric elastic material
Implementation Method 2
a dielectric elastic material is compressed
Implementation Method 3
the capacitive hysteresis loss ratio is reduced by controlling the stress difference between elastic layers
Implementation Method 4
the first elastic layer and the second elastic layer exhibit different stresses as measured during compression and decompression
Data Source
AI summary
An object of the present invention is to reduce the hysteresis loss ratio of a capacitive pressure-sensitive sensor by forming elastic layers from two types of elastic materials (i.e., a certain elastic material and an additional specific elastic material) when the hysteresis loss ratio is high in the capacitive pressure-sensitive sensor including the elastic layers formed only of the certain elastic material.The capacitive pressure-sensitive sensor includes a first electrode, a first elastic layer, a second electrode, a second elastic layer, and a third electrode that are laminated in this order. The first elastic layer and the second elastic layer exhibit different stresses as measured during compression and decompression at a rate of 0.5 mm/minute at 23° C. when the capacitive hysteresis loss ratio is the maximum, and the stress difference is 3 kPa or more.