PVDF Piezoelectric Coaxial Sensor Jacketing Without Polarization Loss
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Solution Overview
Problem
Piezoelectric coaxial sensors using PVDF experience deterioration of output characteristics due to polarization decrease during the formation of the jacket layer, particularly when adhesives with thermoplastic resins are used in the manufacturing process.
Innovation Solution
The jacket layer is formed using a film with a tape shape that is adhered using a thermoplastic resin with a melting point of 120°C or lower, allowing the jacket layer to be formed without significant polarization loss in PVDF, and additional jacket layers provide noise resistance and ease of handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a thermoplastic resin adhesive is used to adhere the jacket layer during manufacturing, then the jacket layer can be securely fixed, but the polarization of PVDF decreases causing deterioration of output characteristics
Solution Approach 1:
The patent changes the temperature parameter during the adhesion process by using a thermoplastic resin with a low melting point (100°C or lower). This allows the adhesive to be applied at temperatures that do not degrade the PVDF polarization, thus maintaining output characteristics while achieving secure adhesion of the jacket layer.
2Ease of manufacture
If the jacket layer is formed by extrusion molding, then the manufacturing process is simplified, but the polarization of PVDF decreases causing small output
Solution Approach 1:
The patent changes the thermal parameter by specifying a thermoplastic resin with a melting point of 100°C or lower. This allows the jacket layer to be formed by tape winding with low-temperature adhesion, avoiding the high temperatures of extrusion molding that degrade PVDF polarization, while still achieving a manufacturable process.
3Strength
If the jacket layer is formed by tape winding with high-temperature adhesive, then secure adhesion is achieved, but PVDF polarization decreases due to heating
Solution Approach 1:
The patent changes the temperature parameter by using a thermoplastic resin adhesive with a melting point of 100°C or lower. This enables secure adhesion of the jacket layer through tape winding while maintaining the heating temperature below the threshold that would degrade PVDF polarization, thus resolving the contradiction between adhesion strength and temperature control.
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 method suppresses deterioration of output characteristics by maintaining PVDF polarization and enhances noise resistance and handling properties of the piezoelectric coaxial sensor.
Implementation Method 1
an adhering step of heating the sensor portion around which the film to be the jacket layer exposed to the outside is wound at 120° C. or lower to adhere the film to the member by the adhesive layer
Implementation Method 2
a piezoelectric element is arranged between a center conductor and an outer conductor of a coaxial cable. The piezoelectric coaxial sensor, by sensing a voltage of the piezoelectric element generated when a force is applied from an outer peripheral surface of the sensor via the center conductor and the outer conductor, detects the force.
Data Source
AI summary
A piezoelectric coaxial sensor includes: a sensor portion including a center conductor having a linear shape, a polymer piezoelectric layer containing polyvinylidene fluoride and that covers an outer peripheral surface of the center conductor, and a first outer conductor that surrounds an outer peripheral surface of the polymer piezoelectric layer; and jacket layers that each include a film having a tape shape wound to surround an outer peripheral surface of the sensor portion. The film of at least one of the jacket layers exposed to the outside of the piezoelectric coaxial sensor among the other jacket layers is adhered to a member in contact with an adhesive layer by the adhesive layer. The adhesive layer includes a thermoplastic resin having a melting point of 120° C. or lower.