| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical encoder which uses a reflecting lattice and a light transmission-type lattice, which is based on the theory of three lattices, which is small and compact and whose resolution is high. SOLUTION: In this optical linear encoder 1, light from an LED 2 passes a light transmission moving lattice 31 formed on a semiconductor moving plate 3 so as to be then reflected by a reflecting grating 41 on a reflecting grating plate 4. A reflected grating image is detected by a lattice-shaped photodiode 32 formed on the semiconductor moving plate 3. The moving lattice 31 and the photodiode 32 are formed on a common semiconductor substrate, and lens effect is obtained by the lattice-shaped photodiode 32. As a result, a lens optical system is not required, and the encoder which is small and compact can be realized. In addition, on the basis of the theory of three lattices, whether the interval between the reflecting grating and the moving grating is wide or narrow and a change in the interval do not have a bad influence on the detecting accuracy of the encoder. As a result, the components can be attached simply, and the restriction on the mounting position of the components is relaxed.
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