ULTRASONIC TRANSDUCER, ULTRASONIC DIAGNOSTIC SYSTEM AND ULTRASONIC MICROSCOPE

摘要

PROBLEM TO BE SOLVED: To provide a capacitance type ultrasonic transducer, an ultrasonic diagnostic system and an ultrasonic microscope which can transmit and receive ultrasound waves with a sufficient acoustic pressure and sensitivity while removing the necessity for application of DC bias voltage by providing an electret.

SOLUTION: The ultrasonic transducer consists of a transducer cell which is composed of a first electrode, a vibrating membrane arranged on the first electrode through an air gap and a second electrode supported by the vibrating membrane and an electret layer which retains electric charges and provides a specific potential between the first electrode and the second electrode. In this case, the electret layer is arranged in a region which is separated from the transducer cell when it is viewed from the direction of transmission of ultrasound waves generated by vibration of the vibrating membrane.

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