| 摘要 |
PURPOSE:To prevent the reproduction defect of information and off-tracking by selectively forming reflection films only in the ROM region in such a manner that the reflectivity of the ROM region attains the reflectivity equal to or higher than the reflectivity of a RAM region. CONSTITUTION:The optical disk is formed by being divided to the RAM region 1 and the ROM region 2. Pregrooves 3 are formed in the RAM region 1 and prepits 4 are formed in addition to the pregrooves in the ROM region 2. A recording film 6 is formed on the surface of a substrate 5 across such RAM region 1 and ROM region 2. Further, the Ni films as the reflection layers 7 are laminated on the surface of the recording film 6 where the reflectivity of the RAM region 1 corresponds to the ROM region 2 in such a manner as to attain the reflectivity equal to or higher than the reflectivity of the RAM region 1. The stability of the tracking control and focus control is improved in this way and the troubles, such as the reproduction defect of information and the offtracking, are eliminated. |
