Patent ID: 8767516
Filing Date: 2014-07-01
Classification: G11B

Abstract:
1. A reproduction method for reproducing an optical information storage medium in which a plurality of information recording layers are laminated, each of the plurality of information recording layers including a recording mark having a length shorter than an optical system resolution limit, the optical information storage medium having an internal opening in the vicinity of which medium information is stored by a recording mark longer than the optical system resolution limit, the medium information indicating whether or not the optical information storage medium is a multi layer super resolution optical information storage medium, the method comprising the steps of: reading the medium information, recorded by the recording mark longer than the optical system resolution limit, which indicates whether or not the optical information storage medium is a multi-layer super resolution optical information storage medium; and in reading an information recording layer closest to a reproduction-laser-incident surface of the optical information storage medium on the basis of the medium information indicating whether or not the optical information storage medium is a multi-layer super resolution optical information storage medium, the information recording layer including a recording mark having a length shorter than an optical system resolution limit, reading the information recording layer with reproduction laser power that is set to be lower than reproduction laser power for reading an information recording layer farthest from the reproduction-laser-incident surface, wherein the reproduction laser power for reading the information recording layer closest to the reproduction-laser-incident surface is set to be 0.6 mW to 1.2 mW.