| 摘要 |
PURPOSE:To enable a distance to be measured with a high accuracy by inputting the output of first and second photosensors to an arithmetic control unit and slidingly controlling a condenser lens so that calculated values obtained from the output of the photosensors become prescribed values determined in advance. CONSTITUTION:A condenser lens 10 collects a laser beam from a semiconductor laser 1 and irradiates the beam onto an object 11 to be measured. On the other hand, a measuring optical system 20 overlaps reflected beam from the object 11 to be measured and that from a reference reflector 17 to generate a measuring beat wave and a reference optical system 21 overlaps laser beams reflected from reference reflectors 24 and 26 to generate a reference beat wave. An arithmetic sequence unit 15 calculates and measures a distance to the object 11 to be measured from the ratio between the numbers of the measuring waves and the reference waves generated by the optical systems 20 and 21, respectively, and the known distances to the reflectors. The output of a photosensor 50 disposed inside the focus of a lens 46 and the output of another photosensor 51 disposed outside the focus of a lens 47 are inputted to the unit 15 and the condenser lens 10 is controlled by driving means 55 so that a calculated value obtained from the output of the photosensors has a prescribed one.
|
