To solve a problem of a conventional flexible piezoelectric element wherein the ambient temperature of a piezoelectric element must be managed by means of an extra temperature sensor.
The flexible piezoelectric element comprises a composite piezoelectric sheet 23 produced by admixing a polymer parent material 21 with piezoelectric ceramic power 22, flexible electrodes 24 arranged on the opposite sides of the composite piezoelectric sheet 23, an output voltage detecting means 27 connected with both flexible electrodes 24, an insulation layer 25 provided on at least one side of the flexible electrode 24, a shield electrode 26 provided on the surface of the insulation layer 25, and means 28 for detecting the capacitance of the composite piezoelectric sheet 23. Since the temperature of the flexible piezoelectric element can be detected by measuring the capacitance of the composite piezoelectric sheet 23 through the means 28 for detecting the capacitance, a flexible piezoelectric element having a high detection accuracy and capable of temperature detection can be realized through a simple arrangement.
NAGAI TAKESHI
KANAZAWA SHIGETOSHI
ITO MASAHIKO
