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OPTICAL ENTIRE-CIRCUMFERENCE ENCODER AND MOTOR SYSTEM

  • US 20110227518A1
  • Filed: 03/15/2011
  • Published: 09/22/2011
  • Est. Priority Date: 03/19/2010
  • Status: Active Grant
First Claim
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1. An optical entire-circumference encoder comprising:

  • a rotation track which is rotatable to follow a rotor rotatable around a rotation axis and which is provided to be in a ring shape around the rotation axis as a center;

    a plurality of rotation slits provided to transmit light at an equal pitch radially around the rotation axis as the center in the rotation track;

    a fixed track which is fixedly set in a ring shape in correspondence with the rotation track on one side of the rotation track and which is divided into a plurality of regions in a circumferential direction of the fixed track;

    a plurality of fixed slits provided to transmit light at an equal pitch in the plurality of regions radially around the rotation axis as the center in the fixed track;

    a light guide to guide light which passed through the plurality of fixed slits and the plurality of rotation slits toward a vicinity of the rotation axis while condensing the light; and

    a plurality of light receivers disposed in the vicinity of the rotation axis to receive the light guided by the light guide in the plurality of regions respectively, the plurality of fixed slits in one of the plurality of regions and the plurality of fixed slits in another region adjacent to the one of the plurality of regions among the plurality of regions in the fixed track being formed so that a phase difference by which a rotation direction of the rotor is determined occurs between light reception signals of the plurality of light receivers.

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