发明名称 Optical information reproduction method and apparatus
摘要 In an optical information reproduction apparatus having optical beam sources having at least two types of wavelengths, an object lens may be damaged by colliding with an information recording medium while driving a focus servo, which is caused by a fake signal generated due to an incompatibility of the wavelength in use with the information recording medium. To solve such a problem, in case the type of the information recording medium is unrecognizable and a focus servo is led in by using the optical beam source having the first wavelength, the focus servo is led in by using the second focus servo lead-in unit which is driven by an output of a near focus point detection unit during an operation of a second focus search unit which renders the object lens move away from the information recording medium.
申请公布号 US7362667(B2) 申请公布日期 2008.04.22
申请号 US20040986300 申请日期 2004.11.12
申请人 MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD. 发明人 KITANO EMI;NAKAMURA MASAYOSHI;NAKAYAMA YOSHIYASU;UEDA YASUO
分类号 G11B7/00;G11B5/58;G11B7/085;G11B7/09;G11B7/12 主分类号 G11B7/00
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