Piezoelectric Sensor With Porous Elastic Layers for Surface Motion
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Solution Overview
Problem
Existing piezoelectric sensors lack elastic properties in the surface direction, preventing them from accurately measuring movements on deformable surfaces such as the human skin, limiting their application to wearable devices.
Innovation Solution
A piezoelectric sensor comprising a porous synthetic resin sheet with conductive fine particles and a binder resin, integrated with elastic signal and ground electrode layers, allowing it to follow surface stretching and contraction, enhancing detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a piezoelectric sensor uses a film of insulating polymer material (such as polyethylene terephthalate and polyethylene naphthalate) as an insulating film, then the sensor structure is stable and electrodes are well-supported, but the sensor lacks elastic properties in surface direction and cannot follow stretching of the body
Solution Approach 1:
The patent changes the physical and chemical parameters of the insulating film by using a porous synthetic resin sheet instead of a dense polymer film. This porous structure allows the material to exhibit elastic properties while maintaining its insulating function, enabling the sensor to follow stretching of the body surface.
Solution Approach 2:
The patent employs a composite structure where the porous synthetic resin sheet serves as both the insulating film and the elastic substrate. This composite material integrates the insulating properties needed for electrode support with the elastic properties needed for stretching followability, resolving the contradiction between structural stability and adaptability.
2Ease of manufacture
If the piezoelectric sensor uses a rigid insulating film structure, then manufacturing and electrode integration are simplified, but the sensor cannot accurately measure movements on deformable surfaces such as human skin
Solution Approach 1:
The patent modifies the mechanical parameters of the insulating film by selecting a porous synthetic resin with appropriate porosity and elasticity. This allows the film to deform with the underlying surface while maintaining its insulating properties, thereby enabling accurate movement detection on deformable surfaces like human skin.
Solution Approach 2:
The patent specifically uses a porous synthetic resin sheet as the insulating film. The porous structure provides both mechanical flexibility for following surface deformations and electrical insulation for sensor operation, thus achieving both ease of manufacture and measurement precision on deformable surfaces.
3Ease of manufacture
If the piezoelectric sensor uses conventional non-elastic electrode layers, then electrode fabrication is straightforward, but the sensor cannot maintain adhesion and follow stretching of the body surface
Solution Approach 1:
The patent changes the mechanical properties of the electrode layers by forming them on the porous synthetic resin sheet. The porous substrate allows the electrode materials to conform to surface deformations while maintaining electrical connectivity and adhesion, thus achieving both ease of fabrication and reliability during stretching.
Solution Approach 2:
The patent creates a composite electrode structure where conductive materials are integrated with the porous synthetic resin sheet. This composite approach allows the electrodes to inherit the elastic and adhesive properties of the porous substrate while maintaining their electrical functionality, resolving the contradiction between fabrication simplicity and adhesion reliability.
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 maintains adhesion and accurately measures surface movements, enabling applications like wearable devices and structural health monitoring by detecting vital signals and cracks.
Implementation Method 1
a piezoelectric sheet including a porous synthetic resin sheet
Data Source
Figure 1~3
AI summary
The present invention provides a piezoelectric sensor that has elastic properties in a surface direction thereof, and can smoothly follow stretching of a body to be measured to accurately measure movement of the body to be measured, and detect movement in a surface direction of a surface of the body to be measured on which the piezoelectric sensor is disposed. The piezoelectric sensor of the present invention includes: a piezoelectric sheet including a porous synthetic resin sheet; a signal electrode layer that is layered on a surface of the piezoelectric sheet and contains conductive fine particles and a binder resin having elastic properties; and a ground electrode layer that is layered on another surface of the piezoelectric sheet and contains conductive fine particles and a binder resin having elastic properties.