ULTRASONIC SENSOR, ELECTRONIC UNIT PROVIDED WITH THE SAME AND VEHICLE REAR SONAR

摘要

PROBLEM TO BE SOLVED: To provide an ultrasonic sensor which narrows the half attenuation angle in the directivity characteristic of ultrasonic wave while keeping a reverbation characteristic stable. SOLUTION: The boom part of a cylindrical sensor case 4 is adopted as a diaphragm 5 and a piezoelectric vibrating element 7 is mounted at the nearly center of the inner surface of the diaphragm 5 in the ultrasonic sensor. In the sensor, a carved part whose depth in the direction at right angles to the vibrating surface of the diaphragm 5 is at least equal to or larger than the bottom thickness is formed in the outer peripheral edge of the bottom at the side part of the sensor case 4.