Patent ID: 7692367

Claim:
An ultrasonic transducer comprising: an outer case having a tubular shape including a bottom; a piezoelectric device attached to an inner bottom surface of the outer case; an inner case disposed within the outer case and having a surface arranged to face the inner bottom surface of the outer case so as to define an ultrasonic vibration acting surface arranged such that a mass of the inner case is arranged to restrain vibration of the outer case, the vibration being generated by the piezoelectric device; and terminals electrically connected to the piezoelectric device; wherein the inner case includes a first cutout provided in a portion of the ultrasonic vibration acting surface, the first cutout being arranged to face the piezoelectric device and to flatten an ultrasonic beam generated by vibrations of the piezoelectric device and the outer case; and the inner case includes at least two second cutouts provided in portion of the ultrasonic vibration acting surface that are spaced away from the first cutout.