Patent attributes
An ultrasonic element has a membrane formed as a thin walled portion of a substrate, on which a piezoelectric vibrator is formed. The piezoelectric vibrator comprises a piezoelectric thin film and metal electrode films, which are formed into a sandwiched structure. The piezoelectric vibrator resonates with the membrane at a predetermined ultrasonic wave-band frequency. A hollow-out pattern is formed in the piezoelectric thin film to divide the piezoelectric vibrator into multiple portions, wherein the hollow-out pattern is formed in such an area corresponding to stress concentrated area which appears in vibrations of the membrane in diametrical directions thereof. The membrane is made to be easily deformed in response to vibration of the piezoelectric vibrator, so that an ultrasound of a higher sound pressure can be emitted.
