Patent ID: 8169855

Claim:
An ultrasonic sensor unit comprising: a transmission base plate including an ultrasonic transmission sensor array having a plurality of ultrasonic transmission sensors configured and arranged to transmit ultrasonic waves; and a reception base plate including an ultrasonic reception sensor array having a plurality of ultrasonic reception sensors configured and arranged to receive the ultrasonic waves, the reception base plate and the transmission base plate being layered together so that the ultrasonic transmission sensors and the ultrasonic reception sensors do not overlap as viewed in a planar direction and as viewed in a normal direction of the transmission base plate and the reception base plate, one of the transmission base plate and the reception base plate defining a plurality of through-holes at positions corresponding to one of the ultrasonic transmission sensors and the ultrasonic reception sensors provided in the other of the transmission base plate and the reception base plate so that the one of the ultrasonic transmission sensors and the ultrasonic reception sensors are exposed through the through-holes.