| 摘要 |
PURPOSE:To obtain a compact and thin encoder, whose assembling accuracy is tolerant, by a consititution, wherein a light emitting element and a light receiving element are provided on one side of a slit plate side by side, and the first and second reflecting mirrors are fixed on the other side of the slit plate. CONSTITUTION:A moving slit plate 13, which has slits 12 provided as a specified interval, is an annular body that is attached to a rotary shaft. The plate 13 is moved in the direction X shown by an arrow, with the rotation of the rotary shaft. Light from a light emitting element 2 is reflected by a reflecting surface 16a of a first reflecting mirror and a second reflecting mirror 17 by way of a slit 12a, and received by a light receiving element 3 by way of a slit 12b. When the light has passed the slit 12a in the oblique direction, the light is dispersed by notched parts 19 and does not reach the second reflecting mirror 17. Therefore, accurate reading can be performed without fixed slits for obtaining a shutter effect. Since the light emitting element 2 and the light receiving element 3 are provided on one side of the slit plate 13, the device can be made thin. |
