发明名称 |
Process and system for optical recording and reading on a mobile data carrier |
摘要 |
A process and device for focussing a light energy beam on a data carrier comprising sites formed of virgin areas free from any data recording provided along tracks and serving as reference plane for said focussing. In a preferred variation, these areas are preceded by flags associated with a specific code. Control is achieved by measuring the deviation between the plane of focussing of a beam into a spot scanning the tracks and the reference plane formed by the surface of the virgin areas. Between two passages of these areas the measurements are stored. The focussing error signal is obtained by filtering these measurements.
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申请公布号 |
US4561082(A) |
申请公布日期 |
1985.12.24 |
申请号 |
US19830503655 |
申请日期 |
1983.06.13 |
申请人 |
THOMSON-CSF |
发明人 |
GERARD, JEAN-LOUIS;BERTHET, PIERRE;BRICOT, CLAUDE;AUDOIN, MICHEL |
分类号 |
G02B7/28;G11B7/007;G11B7/013;G11B7/08;G11B7/09;G11B7/24;(IPC1-7):G11B7/00 |
主分类号 |
G02B7/28 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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