| 摘要 |
PROBLEM TO BE SOLVED: To miniaturize an optical encoder and make it high accuracy, and herewith enhance a coefficient of utilization of light. SOLUTION: A plurality of lenses 4 arranged at constant pitches along a movement direction on a surface of a movement plate 3 are formed. Mountain shaped prisms 5A, 5B are formed continuously in the movement direction on a backside of the plate 3. By light-emitting elements 1A, 1B, a luminous flux modulated in intensity through the leneses 4 passing through with a moving of the plate 4 is incident on the prisms 5A, 5B. Light-receiving elements 2A, 2B receives the luminous flux radiated from the prisms 5A, 5B through the lenses 4 passing through with the moving of the plate 3 in the same way to output a detection signal expressing a movement amount of the plate 3. The plate 3 is provided with two trucks separated in a width direction and extended in the movement direction. Two lines of the prisms 5A, 5B corresponding to the two trucks are formed. The receiving elements 2A, 2B corresponding to two trucks separated and arranged by two pieces in the width direction, and respectively receive the flux independently radiated from two trucks to output the movement amount of the plate 3 and therewith the detection signal expressing the movement direction.
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