| 摘要 |
PROBLEM TO BE SOLVED: To provide a recording medium layer consisting of material which gives rise to a reversible change between an optically identifiable states by irradiation with a laser beam on a substrate and means giving a suitable thermal conductivity in at least one dielectric substance above and below this layer and preventing the deterioration in the recording characteristics after preservation under high-temp. and high-humidity conditions. SOLUTION: The material consisting essentially of Zn, S, Si and O is used as the dielectric layer 4 held by a recording layer 3 and a reflection layer 5. The compsn. ratio of the S to the Zn in the film is smaller than 1. More particularly, the compsn. ratio of the O to the Si is preferably smaller than 2. The compsn. ratio of the Zn and the S is preferably made larger than 1 on the main surface of the recording layer 3 of the side opposite to the reflection layer 5 for the number of cycle recording times. Further, if the nitride or nitrooxide of either of Ge or the recording layer 3 material is used as the boundary phase therebetween, a desirable result is obtd. as the number of cycle recording times is improved and the weatherability is stabilized. |
