| 摘要 |
PURPOSE:To record rewritable information and non-rewritable information on the same medium by providing a board and a recording medium exhibiting a phase transition at lower than crystallizing temperature with low melting point metal formed on the board and exhibiting 2-phase separation if heating at the crystallizing temperature or higher. CONSTITUTION:An optical disk has a board 1, and a recording film 2. The board 1 is formed, for example, of polycarbonate resin, and the film 2 is formed, for example, of InSe of low melting point metal. When the film 2 is heated by a laser light and then quenched, it becomes a noncrystalline amorphous part 3, while when it is gradually cooled, it becomes a crystalline part 4 of crystalline state. The state is reversible, and can be reversed several times. The film 2 exhibits about 10% of reflectivity on the part 3 and about 20% on the part 4. When the film 2 is heated to a crystallizing temperature or higher, it is separated to two states to become two-phase separated part 5. The part 5 does not change its state, and exhibits a reflectivity of intermediate between those of the crystalline state and the amorphous state. This film is used to record nonrewritable and rewritable information on the same medium. |
