OPTICAL INFORMATION RECORDING, REPRODUCING AND ERASING MEMBER

摘要

PURPOSE:To improve recording and erasing characteristics and to stabilize cycle characteristics by changing the material of a dielectric layer of a rear surface and a dielectric layer of a front surface and adopting the constitution to select the film thickness on a substrate side large and the thermal conductivity small on the rear surface side. CONSTITUTION:The 1st inorg. dielectric layer 1 on the rear surface which has the heat conductivity as small as 1.6.10<3>Cal/Cm. deg.C and consists essentially of ZnS is previously formed as the dielectric material having excellent heat resistance on, for example, the front surface and an alloy thin film 2 consisting of Te-Ge-Sb is formed thereon. The 2nd inorg. dielectric layer 3 of the front surface is further provided on this recording thin film layer and the different dielectric material is used. Particularly the film essentially consisting of AIN having the large heat conductivity is selected. A reflecting layer 4 above-mentioned consisting of Al is provided thereon and the dielectric material 1 for the rear surface is selected at <=200nm as the film thickness. The dielectric material 3 of the front surface is selected at <=100nm. The C/N of the recording signal obtd. in this way is >=55dB and the erasing characteristics obtd. are >=30dB overwriting erasing.