| 摘要 |
PURPOSE: An encoder is provided to easily manufacture a code wheel, improve an accuracy and reliability to a signal detection, and realize a compact component by using a code allowing a reflector to adhere to a circulating plate, utilizing a surface emitting laser(SEL) diode as a light source and a hologram device as a condensing and a light path change unit, and modulating the SEL. CONSTITUTION: A circulating plate(200) is comprised of a reflector(210) sequentially and continuously arranged with a reflection surface and non-reflection surface at an edge of a side surface and is installed on the axis of rotation so that a circulation becomes possible. A light source discharges a light beam at the reflector(210). A first optical unit performs a focusing operation on the reflector(210) by condensing the light beam discharged from the light source. A second optical unit is provided on the light path between the reflector(210) and the first optical unit to condenses the light beam discharged from the light source. The second optical unit performs a focusing operation on the reflector and, at the same time, changes the path of the light beam reflected by the reflector(210). A light detection unit receives the light beam whose path is changed by the second optical unit. The light source, the optical unit, the second optical unit and the light detection unit are mounted on a lead frame(500) and packaged to a module with a resin molding.
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