Development of sensor devices using piezoelectric vibration in low frequency ultrasonic region

The sensor devices operated in low frequency ultrasonic region usually contain the piezoelectric element driven by flexure vibration mode. Two successful examples of these devices as piezoelectric vibration gyroscope and SMD type ultrasonic transducer are reviewed. In both cases, reversibility of piezoelectricity has play an important role for simplifying the structure and cost reduction. Designed structure to minimize the leak of vibration generated by flexure vibration is key factor for improved performance and reliability which must be critical in miniature size. © 2020 Japan Society of Powder and Powder Metallurgy.