| 摘要 |
PURPOSE:To obtain highly accurate resolving power, by such a simple structure that a plurality of light source, a pair of light receiving parts, an encoder and a pair of optical elements, etc. are provided. CONSTITUTION:A light source mount plate 10 has a plurality of light sources, for example, four light source i-iv arranged thereto at an equal interval of 90 deg. and pair of light receiving parts 50, which are constituted of light receiving windows I1, IA-IVd, IVD arranged on a light receiving window mount plate 6, receive one of lights emitted from the light sources i-iv to output a pulse signal P0 having predetermined phase difference. An encoder plate 30, which is provided with optical element slits a, A-e, E capable of transmitting lights emitted from the light source i-iv to the light receiving part 50 one at a time in succession, is provided between the light source mount plate 1 and the light receiving window mount plate 6. These slits a, A-e, E form pair constitution having predetermined position difference so that electric row signals having predetermined phase difference are outputted from the light receiving parts 50 and the arrangement number of said slits are set so as to becomes more than the number of the light sources i-iv by one piece and mechanical displacement is converted to an electric signal with high resolving power and high accuracy.
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