| 摘要 |
PROBLEM TO BE SOLVED: To obtain a sufficiently large reproduced signal amplitude by specifying the film thickness of a first protective layer to a thickness within the first period of the change in the difference in reflected light quantity between the crystalline and amorphous states induced by an interference effect when the surface of a substrate is irradiated with reproducing light. SOLUTION: The first protective layer 13, the recording layer 14, the second protective layer 15 and a reflection layer 16 are successively formed in the groove part 12 of the polycarbonate(PC) substrate 11. The information recording medium has the groove part 12 which is formed on the substrate 11, the first protective layer 13 which has a sectional shape nearly identical to the sectional shape of the groove part 12, the recording layer 14 which is formed on the protective layer 13 and records information by the phase transition occurring between the crystalline state and the amorphous state according to the irradiation quantity of a light beam, the second protective layer 15 which is formed on the first recording layer 13 and the reflection layer 16 which is formed on the second protective layer 15. The film thickness of the first protective layer 13 of the information recording medium is specified to a thickness within the first period of the change in the difference in the reflected light quantity between the crystalline and amorphous states induced by the interference effect when the surface of the substrate 11 is irradiated with the reproducing light. |
