发明授权
- 专利标题: Focus control system for optical read-out apparatus
- 专利标题(中): 光学读出装置的对焦控制系统
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申请号: US19596申请日: 1979-03-12
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公开(公告)号: US4243848A公开(公告)日: 1981-01-06
- 发明人: Yoshihiro Utsumi
- 申请人: Yoshihiro Utsumi
- 申请人地址: JPX Tokyo
- 专利权人: TEAC Corporation
- 当前专利权人: TEAC Corporation
- 当前专利权人地址: JPX Tokyo
- 优先权: JPX53/32019 19780320
- 主分类号: H04N5/85
- IPC分类号: H04N5/85 ; G02B7/28 ; G11B7/09 ; G11B7/12
摘要:
In a video and/or audio disc player wherein a laser beam is focused by an objective on a record disc for scanning same along a spiral information track thereon, a focus control is provided which comprises a converging lens disposed across the path of the information-modulated laser beam. Two or three photodetector elements are disposed on one of the conjugate planes of the converging lens the other of which substantially coincides with a focal plane of the objective. Aligned in the direction in which the successive images of pits on the record disc travel thereover, the photodetector elements produce electrical outputs having a phase relationship representative of the variable distance between record disc and objective. A focus control circuit produces an output signal corresponding to the phase relationship of the outputs from the photodetector elements, for delivery to a drive coil capable of electromagnetically moving the objective toward and away from the record disc for readjustment of the distance therebetween.
公开/授权文献
- US6122550A Device for therapeutic action on human organism 公开/授权日:2000-09-19
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