| 摘要 |
<P>PROBLEM TO BE SOLVED: To stably determine media type in an optical disk device that has a means for detecting difference and sum signals generated from a plurality of beams. <P>SOLUTION: A servo controller 104 detects the thickness of a transparent layer from a light incident surface to a recording surface of an optical disk 101 using a sub sum signal that is generated based on reflected light of sub beams intoto which reflected light of main beams has leaked, determines the type of the optical disk 101 based on the thickness of the transparent layers, and detects the number of recording layers of the optical disk 101 using a focus S-signal. <P>COPYRIGHT: (C)2012,JPO&INPIT |
