ULTRASONIC SENSOR

摘要

PROBLEM TO BE SOLVED: To provide an ultrasonic sensor for efficiently transmitting and receiving ultrasonic waves. SOLUTION: The ultrasonic sensor 1 comprises a case 2 having an opening at a part that opposes a sound source; a plate 3 that is arranged at the opening of the case 2 and has a pattern where light is alternately transmitted or is not transmitted in a plurality of annular regions formed by a plurality of concentric circles; and a horn 4 that is arranged inside the case 2 while a reciving surface is made to face the opening and receives ultrasonic waves from the sound source. COPYRIGHT: (C)2004,JPO