| 摘要 |
PROBLEM TO BE SOLVED: To use substantially as a reflection type encoder by configuring diffraction gratings of a main scale together with an index scale of transmission type. SOLUTION: The optical encoder is equipped with a main scale 10 formed with transmission type diffraction gratings, a light source 12 for vertically irradiating a parallel light beam on the main scale, a reflecting surface 14 arranged in parallel on the opposite side of the light source with respect to the main scale, an index scale 16 formed with the transmission type diffraction gratings arranged in parallel on the same side of the light source with respect to the main scale, light receiving elements 18, 20 for sensing an interference light formed after the light transmitted during being vertically irradiated on the main scale has been reflected by combining first diffracted lights L(0,1) L(0,-1) and second diffracted lights L(1,-1) L(-1,1) formed due to diffraction at different position on the main scale using the index scale. COPYRIGHT: (C)2004,JPO
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