| 摘要 |
PROBLEM TO BE SOLVED: To provide a photoelectric encoder which reduces degradation in measurement accuracy due to variation in temperature and humidity.SOLUTION: A photoelectric encoder includes: an irradiation part which radiates first and second irradiation light beams of a first linear polarization; a scale which diffracts the first irradiation light beam to produce a first diffraction light beam of the first linear polarization and diffracts the second irradiation light beam to produce a second diffraction light beam of the first linear polarization; a polarization part which converts the first diffraction light beam to a third diffraction light beam of a second linear polarization perpendicular to the first linear polarization, combines the second diffraction light beam and the third diffraction light beam so as to produce a first combined light beam and a second combined light beam, and converts the first combined light beam to a third combined light beam of circular polarization; and a light beam receiver which receives each of the second combined light beam and the third combined light beam. The scale includes a glass plate having a grating-shaped surface. |
