INFORMATION RECORDING MEDIUM

摘要

PROBLEM TO BE SOLVED: To provide good recording and reproducing characteristics in recording and reproduction with blue laser by disposing an information recording thin film which records information by a change of its atomic arrangement caused by irradiation with light as a recording layer on a substrate and making the refractive index of the recording thin film in the amorphous state at wavelength for reproduction higher than that in the crystalline state. SOLUTION: An information recording thin film which records information by a change of its atomic arrangement caused by irradiation with light is disposed on a substrate and the refractive index of the recording thin film in the amorphous state at wavelength for reproduction is made higher than that in the crystalline state. When recording is carried out on the recording thin film, the reflectance in the amorphous state is lower than that in the crystalline state and recording starting power in the recording of the shortest mark on the amorphous state is equal to or smaller than that in the recording of the shortest mark on the crystalline state under the same conditions. When the recording thin film is used for a high density rewritable phase change type information recording medium for blue laser, good recording characteristics are provided.