| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical encoder having a small output phase fluctuation caused by eccentricity of a rotary slit and high utilization efficiency of light. SOLUTION: A rotor plate 1 of this optical encoder has slits 11 formed thereon along the circumferential direction, and transmits intermittently light from a light emitting element 3 following rotation. A fixed plate 2 has apertures 21A, 21B, and separates the light transmitted through the rotor plate 1 into at least two beams having mutually shifted intermittent phases. Light receiving elements 4A, 4B receive the beams respectively, and output at least two electric signals having frequencies corresponding to intermittence and the mutually shifted phases. Light guide members 5A, 5B guide light from the fixed plate 2 to the light receiving elements 4A, 4B, while enlarging the interval between the adjacent beams, to thereby enable to arrange the light receiving elements 4A, 4B at the enlarged interval. The light guide members 5A, 5B wherein incident faces 51A, 51B for taking the beams comprise projecting curved faces bundle the beams and guide the beams efficiently to outgoing faces 52A, 52B. COPYRIGHT: (C)2004,JPO&NCIPI
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