| 摘要 |
A phase change mode optical disk comprising a transparent substrate, a recording layer provided on the transparent substrate and subjected to crystalline-amorphous phase change on radiation by laser power, and protective layers provided directly below and above the recording layer, the recording layer being expressed by a general formula (SbaTebGec)100-d.Sd in which ratios of the number of atoms of the components satisfy the relations, 5 <= a <= 60, 35 <= b <= 65, 5 <= c <= 65, a+b+c=100 and 0 /< d <= 40, or/and either one or both of the protective layers being formed by a mixture of Zn(1-x)Sx and at least one kind of substance (when a metal is zinc, sulfide is excluded) selected from oxide, nitride, fluoride, carbide and sulfide of a metal or a metalloid, a ratio x of the number of atoms of sulfur in Zn(1-x)Sx being x > 0.50. The optical disk according to the present invention enables the repetition characteristics of recording and erasure, i.e a possible number of repetitions and a possible number of readings to be improved, and the deterioration of a recording mark, which is ascribed to many-hour reproduction, to be substantially prevented.
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