ULTRASONIC TRANSDUCER USING RELAXOR FERROELECTRIC POLYMERS

摘要

The present invention relates to an ultrasonic transducer using a relaxor ferroelectric polymer. The present invention provides an ultrasonic transducer using a relaxor ferroelectric polymer which comprises a piezoelectric layer formed of a relaxor ferroelectric polymer material to transmit and receive an ultrasonic wave to and from an examined object; first and second electrodes laminated on the upper and lower surfaces of the piezoelectric layer, respectively; an AC voltage part for applying or sensing an AC voltage between the first and second electrodes; and a DC voltage part for applying a DC bias voltage between the first and second electrodes. The inner polarization of the piezoelectric layer is aligned in a thickness direction when the DC bias voltage is applied to the piezoelectric layer, so that an electromechanical coupling coefficient is increased. According to the ultrasonic transducer using a relaxor ferroelectric polymer,a relaxor ferroelectric polymer of P(VDF-TrFE-CFE) or P(VDF-TrFE-CFE) is used as piezoelectric material, so that the electromechanical coupling coefficient is high and thermal stability is enhanced. In addition, high sensitivity and a large bandwidth are provided so that performance of the ultrasonic transducer can be greatly improved.