发明名称 |
Apparatus and method for measuring focusing characteristics of optical pickup and/or optical disc and apparatus and method for recording and/or reproducing optical disc |
摘要 |
A device for measuring focusing characteristics of an optical pickup and/or an optical disc capable of measuring characteristics of focusing states with high accuracy by a simplified circuit. An arithmetic-logic unit 12d controls an offset supplying circuit 23 for applying an offset voltage to a focusing servo control signal. This arithmetic-logic unit 12d detects an error rate of the playback data in such a state in which the focusing position of the laser light is deviated by a pre-set offset amount. The arithmetic-logic unit 12d sequentially varies the offset voltage to repeat the above processing for detecting the error rate. The arithmetic-logic unit 12d approximates the relationship of the error rate to the offset amount by a quadratic curve based on detected data. The offset amount which minimizes the error rate is found from this equation of approximation.
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申请公布号 |
US6246041(B1) |
申请公布日期 |
2001.06.12 |
申请号 |
US19980182845 |
申请日期 |
1998.10.29 |
申请人 |
SONY PRECISION ENGINEERING CENTER (SINGAPORE) PTE LTD.;DISK WARE CO. LTD. |
发明人 |
NAKAYAMA AKIHITO;SHINTANI KENJI;KOHAMA SHUNSUKE;HASHIMOTO YUKARI |
分类号 |
G01M11/00;G11B7/00;G11B7/005;G11B7/085;G11B7/09;G11B20/18;(IPC1-7):G02B27/40;G11B11/00 |
主分类号 |
G01M11/00 |
代理机构 |
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代理人 |
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主权项 |
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