| 摘要 |
PROBLEM TO BE SOLVED: To suppress a side lobe and to sharpen the wave transmitting-receiving direction characteristic in an ultrasonic sensor which is used for crime prevention or the like. SOLUTION: An ultrasonic vibrator T for wave transmission and an ultrasonic vibrator R for wave reception are arranged at a reflector 10 so as to have an orthogonal relationship. Ultrasonic waves which are outputted from the ultrasonic vibrator T for wave transmission are reflected in a region T so as to be wave-transmitted in the direction to a main sensor. Ultrasonic waves which are reflected by a reflecting object Q are reflected in a region R so as to be wave-received by the ultrasonic vibrator R for wave reception. The beam cross section of a wave transmitting beam and that of a wave receiving beam are flat, and both beam overlap each other partially by using their beam axis as the center. Thereby, when both beams are integrated as a result, a sharp wave transmitting-receiving direction characteristic is obtained. In addition, a side lobe is reduced. A composite sensor can be constituted by combining an ultrasonic sensor with an infrared sensor.
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