| 摘要 |
[Problem] To provide a reflection-type encoder which is capable of detecting both a movement amount and a movement direction using a single light source, which has high reliability using a simple construction, and which can easily be made compact. [Solution] In relation to a reference beam of a reflection-type encoder in which an interference optical system is sandwiched between a diffraction grating provided on a rotor or a linear scale, and a laser oscillator and a light receiving unit, by setting an optical path length of the reference beam to at most 4 mm, the overall size of the reflection-type encoder can be reduced while maintaining the reliability and accuracy of the encoder. |
