| 摘要 |
PROBLEM TO BE SOLVED: To achieve both the high-speed detection of objects and the high-resolution measurement of physical quantities. SOLUTION: A physical quantity sensor includes a semiconductor laser 1; a photo-diode 2 for receiving a laser beam radiated from the semiconductor laser 1 and its optical return; an object detection device 11 for detecting the period of an interference waveform contained in output signals of the photo-diode 2 and generated by the self-mixing effect of the laser beam radiated from the semiconductor laser and its optical return and determining the presence of an object 12 in the radiating direction of the laser beam when the interference waveform having a period different from the period of an interference waveform by a reflecting wall surface 10 satisfies prescribed conditions; and measuring means (a current-voltage converting amplifier 5, a filter circuit 6, a counter 7; and an arithmetic unit 8) for measuring the physical quantity of the object 12 on the basis of interferences contained in output signals of the photo-diode 2. COPYRIGHT: (C)2009,JPO&INPIT |
