Original document(17 pages)  中文版
    The present invention relates to a focus control apparatus and method of controlling focus of a radiation beam onto a first spatial level of a record carrier, wherein a focus control loop is locked onto a reflection signal obtained from a second spatial level located at a predetermined distance from said first spatial level, and is then opened to move an objective means towards the second spatial level by a predetermined amount related to the predetermined distance. This stepwise procedure enlarges the margin for mechanical overshoot and hence reduces the risk of bumping into the disc. Additionally, no ambiguous focus error signals are detected and robustness of initial focusing is improved if a thin transparent cover layer is present.
Application Number
申请号
200580002747 Application Date
申请日
2005.01.10
Title 名称 Focus control scheme with jumping focal point
Publication Number
公开号
1910666 Publication Date
公开日
2007.02.07
Approval Pub. Date Granted Pub. Date
International Classification 分类号 G11B7/085
Applicant(s) Name
申请人
Koninkl Philips Electronics NV
Address 地址
Inventor(s) Name 发明人 Zijp Ferry;Van Der Mark Martinus B.
Attorney & Agent 代理人 li jinglan chen jingjun
More information 更  多  信  息


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