| 摘要 |
PURPOSE:To measure a wide speed range accurately by branching incident reflected light an photodetecting each branched light beam by an individual photoelectric converting element, and providing a grating-shaped slit with a different slit interval on the front surface of each photoelectric converting element individually. CONSTITUTION:A half-mirror 11, the 1st and the 2nd grating-shaped slits 12 and 13, lenses 14 and 15, and the 1st and the 2nd photoelectric converting elements 16 and 17 are installed in a light-shielding case 5. The incident light 4 based upon reflected light 3 is branched by the half-mirror 11; one branched light beam is photodetected by the photoelectric converting element 16 through the grating-shaped slit 12 and lens 14, and the other beam is photodetected by the photoelectric converting element 17 through the grating-shaped slit 13 and lens 15. |
