| 摘要 |
PROBLEM TO BE SOLVED: To detect the distance and direction of an object in a detection area with a wide field of view by increasing an S/N ratio without reinforcing an ultrasonic transmitter circuit. SOLUTION: The object detector comprises: a wave transmitter 1 for transmitting an ultrasonic wave; a plurality of wave receiving elements 2 for receiving a reflected wave and converting it into a wave reception signal; and a detection section for determining the distance to an object under measurement corresponding to the time elapsed from the transmission to the reception of the ultrasonic wave on the basis of the wave reception signal and determining the direction of the object under measurement corresponding to the time difference of the reception signal in the wave receiving elements 2 to detect the object under measurement. The object detector further comprises an ultrasonic lens 4 which changes the wave transmission direction and narrows the detection area when it is placed forward of the wave transmitter 1. The detection section 3 performs object detection without the ultrasonic lens 4 placed forward of the wave transmitter 1 and then performs object detection with the ultrasonic lens 4 placed forward of the wave transmitter 1 so that the directivity of the ultrasonic wave transmitted by the wave transmitter 1 is increased. COPYRIGHT: (C)2007,JPO&INPIT
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