When the pulse voltage is supplied to the electrodes 40, 42 of the transducer elements 36 through the printed circuit 48 and ground electrodes 46, {HEAD ~ the piezoelectric element} 38 of each transducer element 36 is actuated to issue {TAIL ~ an ultrasonic wave} 
is actuated to issue
When the pulse voltage is supplied to the electrodes 40 , 42 of the transducer elements 36 through the printed circuit 48 and ground electrodes 46 , { HEAD ~ the piezoelectric element } 38 of each transducer element 36 is actuated to issue { TAIL ~ an ultrasonic wave }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH REL REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL