| 摘要 |
PURPOSE:To increase the degree of freedom of design when a position detector is fitted to various machineries by providing a moving slit plate with plural origin display slit parts and a detecting mechanism for optional specific positions of the slit parts. CONSTITUTION:The moving slit plate 2 is provided with plural origin display slit parts 7, the detection part 11 of the optional specific position detecting mechanism for the slit plates 2, etc. Then when a photodetector 13 is irradiated with light from a light source 12 through a specific position detection slit part 10, the presence of the slit plate 2 at a specific position is detected from the fixed position of the detection part 11. Further, the light from the light source 1 is further projected on a photodetector 5 through the origin display slit part 9 of a fixed slit plate 3 to detect the slit plate 2 being at the position of a slit part 7. For the purpose, the detection part 11 is so fixed as to detect the slit part 10 while detecting the position of a slit part 7 used as an origin among the positions of the plural slit parts 7, and the position where those two kinds of detection signals are detected at the same time is used as the origin to select one point among plural origin candidates.
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