| 摘要 |
PROBLEM TO BE SOLVED: To detect an object speedily, and to measure the physical quantity of the object with high resolution. SOLUTION: A physical quantity sensor comprises: a semiconductor laser 1; a photoelectric sensor 10; an object detector 11 for detecting an object 13, based on the output of the photoelectric sensor 10; a modulation mode switching device 12 for radiating modulation light having a first period from the laser 1 in a detection mode and radiating modulation light having a second period longer than the first period from the laser 1 in a measurement mode after detecting the object 13; and measurement means (current-voltage conversion amplifier 5, filter circuit 6, counter 7 and arithmetic unit 8) for measuring the physical quantity of an object from information on interference caused by the self-coupling effect between laser beams radiated from the laser 1 and return light from the object 13 included in the output signal of a photodiode 2. COPYRIGHT: (C)2009,JPO&INPIT |
