Sony Corporation

Tatsuo Hakuta

Junichi Toyoda

Toshiyuki Imagawa

An ultrasonic-wave distance measuring apparatus of the separate transmission and reception type reflection system capable of making the measurable distance longer and improving the precision of the measuring, wherein a distance measurement calculation control circuit in an ultrasonic-wave transmitter starts counting a time simultaneously with the start of vibration of an ultrasonic-wave transmission sensor, the ultrasonic-wave emitted from the ultrasonic-wave transmission sensor is reflected at the object to be measured and detected by an ultrasonic-wave reception sensor, a distance measurement sensitivity correction circuit corrects the sensitivity of the signal from the ultrasonic-wave reception sensor based on sensitivity correction data predetermined in accordance with a type of object and a measurement distance, the signal after the sensitivity correction by the distance measurement sensitivity correction circuit is detected in a detection circuit, and the distance measurement calculation control circuit stops counting when the detection signal exceeds a predetermined level, measures the time from the start of vibration of the ultrasonic-wave transmission sensor to the reception by the ultrasonic-wave reception sensor, and calculates the distance between the object to be measured and the ultrasonic-wave transmission sensor based on the obtained time.

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Tokyo, Japan

Tatsuo Hakuta