发明名称 |
APPARATUS FOR PROJECTING LIGHT BEAM ON OPTICALLY READABLE MEMORY MEDIUM |
摘要 |
An apparatus for playing optical discs is described, in which for a smoother locking-in of the focus servo control the focussing error signal is initially derived from the amplitude of the h.f. signal, followed by a gradual change-over to a difference signal derived by means of subdetectors. In this way the focus control point with the servo loop closed is shifted towards the desired in-focus point. |
申请公布号 |
JPS61278042(A) |
申请公布日期 |
1986.12.08 |
申请号 |
JP19860119396 |
申请日期 |
1986.05.26 |
申请人 |
PHILIPS GLOEILAMPENFAB:NV |
发明人 |
MARUCHINASU PETORASU MARIA BIIRUHOTSUFU;HABERUTASU MASHIASU MARIA RONIE |
分类号 |
G02B7/28;G11B7/085;G11B7/09 |
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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