ULTRASONIC SENSOR DEVICE

摘要

An ultrasonic sensor device includes a substrate, a piezoelectric vibrator, and a Q-factor adjuster. The piezoelectric vibrator includes a pair of detection electrodes that face each other in a thickness direction of the substrate and a piezoelectric body interposed between the electrodes. The piezoelectric vibrator provides a membrane structure which is formed on a surface of the substrate and has rigidity lower than that of a remaining portion of the substrate. An ultrasonic wave is transmitted by the piezoelectric vibrator, and its reflected wave is received by the same piezoelectric vibrator. The Q-factor adjuster adjusts a Q-factor of the piezoelectric vibrator so that the Q-factor can be larger during a transmission period where the piezoelectric vibrator transmits the ultrasonic wave than during a reception period where the piezoelectric vibrator receives the ultrasonic wave.

主权项

1. An ultrasonic sensor device comprising:
an ultrasonic sensor including a substrate and a piezoelectric vibrator, and a Q-factor adjuster, wherein the piezoelectric vibrator includes a piezoelectric body interposed between a pair of detection electrodes that face each other in a thickness direction of the substrate, the piezoelectric vibrator provides a membrane structure that is formed on a first surface of the substrate and has rigidity lower than that of a remaining portion of the substrate, the ultrasonic sensor transmits an ultrasonic wave by the piezoelectric vibrator and receives its reflected wave by the same piezoelectric vibrator, and the Q-factor adjuster adjusts a Q-factor of the piezoelectric vibrator so that the Q-factor is larger during a transmission period where the piezoelectric vibrator transmits the ultrasonic wave than during a reception period where the piezoelectric vibrator receives the ultrasonic wave.