| 摘要 |
PURPOSE:To increase reflectance and contrast by a relatively simple structure of layers and an easy sputtering method. CONSTITUTION:At least an intermediate layer formed by laminating two or more thin films different from each other in refractive index, a phase shift type optical recording layer, an upper dielectric layer and a reflecting layer are successively laminated on a substrate. The reflectance of the resulting medium is >=65% when the recording layer is in a crystalline state and it is <35% when the recording layer is in an amorphous state. A high refractive index thin film as one of the thin films constituting the intermediate layer is made of a semiconductor having a specified complex index of refraction to the wavelength of light for recording and reproduction. The absolute value of the imaginary part of the complex index of refraction is <0.1 and the real part is >=2.5. |
