| 摘要 |
PROBLEM TO BE SOLVED: To provide an absolute position measuring device made to indicate absolute position from the beginning of power turning-on. SOLUTION: A moving grating means 2 having a first optical grating 3 forming a reference length scale with specified intervals, and a second optical grating 4 forming an absolute position pattern at every plurality of the reference length scales provided in parallel to the first optical grating 3; a light reception means 6 having a first light reception means 7 for receiving the light beam having passed the first optical grating 3, and converting to electric signal and a second light reception means 8 for receiving the light beam having passed the second optical grating 4 and converting to electric signal; a relative position operating means 11 for obtaining a period function from the electric output signal of the first light reception means 7, and operating a phase position from the period function; a coarse absolute position operating means 12 for operating the absolute position at every specific interval from the absolute position pattern obtained from the electric output signal of the second light reception means 8; and a fine absolute position operating means 13 for operating the fine absolute position from the output of the relative position operation means 11, and the output of the coarse absolute position operating means 12; are provided.
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