Piezoelectric polymer material, process for producing the same and an ultrasonic transducer utilizing the same.

摘要

A piezoelectric polymer material consisting of a copolymer of vinylidene fluoride and ethylene trifluoride having the value of the thickness extentional electromechanical coupling factor (K<Sub>t</Sub>) of at least 0.05. A process for producing the piezoelectric: polymer material which comprises heat-treating a shaped article comprising a copolymer of 65-95 mol % of vinylidene fluoride and 35-5 mol % of ethylene trifluoride at a heat-treating temperature being in the range of from [crystal phase transition temperature T'<Sub>m</Sub> -5]°C to [melting point temperature Tm]°C before or during poling the shaped article. An ultrasonic transducer utilized the piezoelectric polymer material as a vibrating element. The ultrasonic transducer may be preferably used in an ultrasonic diagnosis.