| 摘要 |
PURPOSE:To obtain high measurement accuracy with less number of optical fibers by providing a vernier part consisting of n+ or -1 pieces of optical fibers relatively movably to a normal scale part consisting of n pieces of regions reflecting to specific wavelengths. CONSTITUTION:The white light from a white light source 16 is allowed to arrive at an optical branching and combining device 14 as well as a branching filter 17 connected to a decoder 20, a binary coding circuit 19 and a photodetector array 18, by way of a half mirror 15. Four pieces of optical fibers disposed at constant intervals to a vernier part 12 are connected to the device 14, and a normal scale part 11 consisting of mirrors M1-Mp which reflect respectively different wavelengths lambda1- lambdap and are of the equally divided length of the length slightly different from the intervals of the optical fibers 13 is opposed to the vernier part 12. When the normal scale part 11 moves vertically, the combinations of the wavelengths reflected from the mirrors and inputting to the fibers 13 change, and said combinations correspond to the rates of displacement of the normal scale part 11; therefore, the rates of displacement are measured by detecting the combination of the wavelengths with the branching filter 17. |
