Sensitivity improvement of diaphragm type ultrasonic sensors by complementary piezoelectric polarization

A simple electrode configuration of piezoelectric ultrasonic sensor has been proposed and the sensitivity has been improved. The new electrode configuration enables to use two parts of both the positive and negative piezoelectric polarizations and to improve the sensitivity compared to conventional sensors by summing up both the absolute outputs. Optimal electrode sizes have been found by theoretical calculation and the sensor with the optimal configuration has been fabricated. The sensitivity of the new sensor has been improved 50% compared with that of conventional sensors.