发明名称 |
Disc focus servo-circuit with ordered reference level setting means |
摘要 |
In order to focus light beams which are projected onto an optical recording medium, the focusing optical system is moved in a vertical direction to the surface of the recording medium. A focus error signal produced by receiving the light returning from the recording medium is compared in turn with a predetermined plurality of reference levels. A focus servo-means is operated when this signal reaches the reference level within the focus pull-in region after passing through a predetermined order of reference levels.
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申请公布号 |
US4740679(A) |
申请公布日期 |
1988.04.26 |
申请号 |
US19860832810 |
申请日期 |
1986.02.25 |
申请人 |
OLYMPUS OPTICAL CO., LTD. |
发明人 |
DOI, MASANORI |
分类号 |
G11B7/085;(IPC1-7):G01J1/20 |
主分类号 |
G11B7/085 |
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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