Patent ID: 7804971
Filing Date: 2010-09-28
Classification: H04R,Y10T

Abstract:
1. An electrostatic ultrasonic transducer comprising: a first electrode provided with a through hole; a second electrode provided with a through hole forming a pair with the through hole of the first electrode wherein an alternating current signal is applied between the first electrode and the second electrode; an oscillation film sandwiched between the pair of electrodes and having a conductive layer wherein a direct current bias voltage is applied to the conductive layer; and a holding member for holding the pair of electrodes and the oscillation film, wherein a value “a” of one side amplitude of the film oscillation is obtained by the following formula: wherein I a height of a step part provided in an outer circumference of the through hole on the respective oscillation film sides of the pair of electrodes in a direction of the oscillation film side is set at a value exceeding and close to the one side amplitude value “a”.