| 摘要 |
PURPOSE:To obtain an optical magnetic memory medium whose read characteristic is excellent in a wide waveform range by setting the film thickness of a dielectric layer thinner than that whose read performance index F can be maximized under light with a wavelength of 800nm and making the F under a light of a 600nm wavelength more than 75% of 800nm. CONSTITUTION:A transparent substrate arranged on the light incident side, the dielectric layer with at least one layer and a magnetic layer with at least one layer are provided in that order. The film thickness of the dielectric layer is made thinner than that where the read performance index F can be maximized under the light with a 800nm wavelength, and the F under the light with a 600nm wavelength more than 75% of the value of 800nm. The dielectric layer is to improve its read characteristic by the interference action of reproduced light. As long as the material of said dielectric layer is substantially transparent with respect to recorded and reproduced light, any type will do. Thus the read characteristic can be excellent in the wide range of reproduced light wavelength with less fluctuation. |
