| 摘要 |
PURPOSE:To provide the phase transition type optical disk medium which can execute recording and reproducing at a high density by using a laser beam of two wavelengths. CONSTITUTION:A sub-surface protective layer 2, a recording layer 3, a super- surface protective layer 4 and a metallic reflection layer 5 are laminated and formed in this order on a transparent substrate 1. A GeSbTe alloy film is used for this recording layer 3. Transparent dielectric films having 1.9 to 2.2 refractive index are used for the super-surface protective layer 4 and the sub-surface protective layer 2. The thickness of the recording layer 3 of such optical recording medium A1 is specified to a 15 to 30nm range, the thickness of the super- surface protective layer 4 to 140 to 200n and the thickness of the sub-surface protective layer 2 to 100 to 140nm or 280 to 320nm. |
