| 摘要 |
PURPOSE:To obtain the DRAW type optical disk which allows reproduction with a reproduction-only optical disk device by successively laminating a 1st layer constituting of a metal and a 2nd layer consisting of an org. dye having a near IR absorptiveness on a substrate and determining the film thicknesses of the respective layers in such a manner that the reflectivity at a reproduction wavelength is higher than the reflectivity at a recording wavelength. CONSTITUTION:A low melting metallic layer 2 having 200 to 800 deg.C m. p. and an org. dye layer 3 having near IR absorptiveness are successively laminated on the substrate 1 and the film thicknesses of the respective layers are optimized so as to attain >=70% reflectivity at 780nm reproducing wavelength and >=10% and <=50% reflectivity at 600nm recording wavelength. The absorptivity decreases and the recording is infeasible if the reflectivity is increased and, therefore, the light beam wavelength at the time of recording is varied from the light beam wavelength at the time of reproducing to the wavelength of the high absorptivity, i.e., low reflectivity. Further, throttling of the light beam 4 is possible and the shorter recording pits are formable as the wavelength is shorter; therefore, the light beam wavelength at the time of recording is made shorter than the light beam wavelength at the time of reproducing. The DRAW type optical disk which allows reproduction with the reproduction-only optical disk as well is obtd. in this way. |
