| 摘要 |
PURPOSE:To stabilize the characteristics of recording and erasing and to obviate the generation of cracks in a crystallization treatment by providing protective layers and a reflection layer which reflects light again to a recording layer on the protective layer on the side where the light transmits the recording layer, imparting the internal stress of compression to the protective layers and imparting the internal stress of tension on the reflection layer. CONSTITUTION:The 1st protective layer 2, the recording layer 3, the 2nd protective layer 4, and the reflection layer 5 are successively laminated by, for example, sputtering method on a substrate 1. The recording layer 3 is heated by irradiation with argon laser beam and the thermal stresses are generated in the respective layers at the time of subjecting the recording layers 3 to the crystallization treatment. The reflecting layer material has the coefft. of thermal expansion larger than the coefft. of thermal expansion of the recording layer material and the protective layer material and, therefore, this material elongates more than the layers adjacent thereto. Then, the force in the tensile direction acts on the protective layers 2, 4 and conversely, the force in the compressing direction acts on the reflection layer 5. The deformation of the optical information recording medium by thermal expansion is thus suppressed. The characteristics of recording and erasing are stabilized from the beginning in this way and the generation of the cracks is obviated even if the crystallization treatment is executed with this power. |
