| 摘要 |
PROBLEM TO BE SOLVED: To discriminate the type of many types of optical disks quickly. SOLUTION: Each part is set to be in an HD DVD mode, and a light beam of 405 nm is generated by a laser light emitter 61 in an optical pickup 60 to be condensed on an optical disk 1 by an objective lens 67 with a numerical aperture of 0.65. When focus servo ON and tracking servo ON are successful by FE, TE for HD DVDs created from the output of a photo detector 69 where reflection beams enter, the medium is identified as an HD DVD. When only the focus servo ON is successful, the medium is identified as a BD. When the focus servo ON fails, a DVD mode is set, a light beam of 650 nm is generated in a laser light-emitting/light-receiving unit 70 to be condensed on an optical disk 1 by the objective lens 67 while the numerical aperture stays at 0.65. When the focus servo ON and tracking servo ON are successful by FE, TE for DVDs created from the output of the laser light-emitting/light-receiving unit 70 where reflection beams enter, the medium is identified as a DVD. When only the focus servo ON is successful, the medium is identified as a CD. COPYRIGHT: (C)2008,JPO&INPIT
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