| 摘要 |
PROBLEM TO BE SOLVED: To reduce uneven initialization caused by optical interference generated during initializing without any deterioration of the information recording/ reproducing signal characteristic of a recording layer. SOLUTION: For a multilayer optical disk constructed by laminating at least first and second information recording layers on a substrate through an intermediate layer, an initializing light is radiated from the first information recording layer side to initialize the first recording layer using a phase transition material as a recording material. In this case, when the numerical aperture of an objective lens used for initializing light irradiation is NA, the length of the longitudinal beam of the initializing light is L, the thickness of a middle layer is D, and the rate of a light quantity transmitted through the first information recording layer, reflected on the second information recording layer and then radiated to the first information recording layer again with respect to a light quantity made incident on the first information recording layer is R1, the initializing light is radiated to satisfy the relation of L×R1<=25[1-exp(-0.0004×NA4×D2)] at the wavelength λi of the initializing light. |
