发明授权
- 专利标题: Optical encorder for detection having a moving reference point
- 专利标题(中): 具有移动参考点的用于检测的光学记录仪
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申请号: US859321申请日: 1997-05-20
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公开(公告)号: US5981941A公开(公告)日: 1999-11-09
- 发明人: Kazumasa Takata , Kanji Nishii , Kenji Takamoto , Masami Ito , Atsushi Fukui , Tomohisa Kishi
- 申请人: Kazumasa Takata , Kanji Nishii , Kenji Takamoto , Masami Ito , Atsushi Fukui , Tomohisa Kishi
- 申请人地址: JPX
- 专利权人: Matsushita Electric Industrial Co., Ltd.
- 当前专利权人: Matsushita Electric Industrial Co., Ltd.
- 当前专利权人地址: JPX
- 优先权: JPX8-123848 19960520; JPX8-323127 19961203
- 主分类号: G01D5/38
- IPC分类号: G01D5/38 ; G01D5/34
摘要:
The present invention provides an optical encoder capable of using the recesses and convexes of a movable plate and a fixed plate to accurately generate a Z phase signal in synchronism with an A/B phase signal. Phase type diffraction gratings on the moving and fixed plates including a plurality of tracks with different grating pitches cause parallel coherent beams to interfere with one another, and a light receiving part detects the intensity of light to obtain a plurality of synchronous signals with different periods. On the other hand, the light receiving part detects light spots formed by condensing elements on the movable plate to generates a single pulse per rotation as a reference position. One of the plurality of synchronous signals that has the shortest period is selected as an A/B phase signal that depends on the movement of the movable plate. The conjunction of the reference position signal and the plurality of synchronous signals is determined as a Z phase signal indicating the origin of the movable plate, thereby obtaining a Z phase signal in synchronism with one pulse of the A/B phase signal.
公开/授权文献
- US5325932A Down reaming apparatus 公开/授权日:1994-07-05