发明名称 |
Information reproducing method and information reproducing apparatus of multilayer optical disk |
摘要 |
When reproducing a multilayer optical disk using a high-numerical-aperture objective, the period of time required before the disk is reproduced is reduced by discriminating recording layers. A spherical aberration signal is detected as a differential signal between focus position fluctuation signals respectively in a central section and in a peripheral section of a reproduced flux of light. A recording layer is discriminated using a quantity of correction of spherical aberration at a zero-crossing point of a level or a spherical aberration signal associated with the differential signal. After adding the spherical aberration for the correction of the discriminated layer, residual spherical aberration is corrected by feedback control using a residual spherical aberration signal.
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申请公布号 |
US7123565(B2) |
申请公布日期 |
2006.10.17 |
申请号 |
US20030368415 |
申请日期 |
2003.02.20 |
申请人 |
HITACHI, LTD. |
发明人 |
ARIYOSHI TETSUO;SHIMANO TAKESHI;MIYAMOTO HARUKAZU |
分类号 |
G11B7/00;G11B7/24;G11B7/005;G11B7/085;G11B7/09;G11B7/095;G11B7/125;G11B7/13;G11B7/135 |
主分类号 |
G11B7/00 |
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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