| 摘要 |
PURPOSE:To enable high-density recording and reproducing by laminating and forming an under coat layer, a recording layer, an over coat layer and a metallic reflection layer successively from below in the order on a transparent substrate and setting the thicknesses of the respective layers at combinations of a specific range. CONSTITUTION:The under coat layer 2 consisting of a transparent dielectric film having 1.9 to 2.2 refractive index, the recording layer 3 consisting of a GeSbTe alloy film, the over coat layer 4 consisting of the transparent dielectric film like wise having 1.9 to 2.2 refractive index and the metallic reflection layer 5 are successively laminated and formed from below on the transparent substrate 1. The thicknesses of the respective layers mentioned above are limited to the properly selected and combined thicknesses, i.e., the thickness of the under coat layer 2 is 160 to 220nm and the thickness of the recording layer is 15 to 30nm, more preferably 200 to 280nm. The short wavelength phase transition optical disk medium relating to the structure can make recording and reproducing at 450 to 670nm wavelength. The high-=density recording and reproducing are thus attained. |
