| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical disk drive and an optical disk type discrimination method which can discriminate, in a short period of time, the type of an arbitrary optical disk among optical disks in which the thickness of substrates formed with recording layers are equal to each other, in particular, the type of an optical disk in which two or more recoding layers are provided. SOLUTION: The optical disk drive identifies the types of the recording media of two or more standards and different in recording density, and the optical disk drive device has: a light source outputting light of the predetermined wavelength; a photodetector 29 detecting reflected light reflected from one information recording layer of a recording medium having at least two layers of information recording layers to which either recording density out of first recording density or second recording density being higher than the first recording density is given; a lens 27 condensing light from the light source to present the minimum spot on one of the information recording layer of the recording medium; and a signal processing circuit 11 discriminating recording density of the recording medium by acquiring a component containing a characteristics peculiar to the information recording layer of the recording medium having the second recording density out of reflected light detected by the photodetector. COPYRIGHT: (C)2008,JPO&INPIT
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