| 摘要 |
PROBLEM TO BE SOLVED: To lower the double refractiveness of a transparent resin layer and to obtain reproduction signals having high quantity by allowing a material having the double refractiveness reverse from the double refractiveness of the transparent resin material to exist between first and second signal layers. SOLUTION: The optical disk is formed by sticking a transparent substrate 1 and a transparent substrate 2 with the transparent resin layer consisting of a UV curing resin as a transparent resin material. The first signal layer 3 is formed on the surface on the inner side of the substrate 1 and the second signal layer 4 is formed on the surface on the inner side of the substrate 2. The reproduction of the signal layer 3 is executed by converging a laser beam 6 with an objective lens 8, condensing this laser beam onto the signal layer 3 and detecting the reflected light thereof. At the time of reproduction of the signal layer 4, a laser beam 7 is converged and is condensed onto the signal layer 4 in the same manner as described above and the reflected light thereof is detected, by which the reproduction is executed. At this time, the laser beam 7 arrives at the signal layer 4 through the inside of the resin layer 5. Then, the quality of the regenerative signals is deteriorated if the resin layer 5 has the double refractiveness with the transparent resin material alone. The material having the double refractiveness reverse from the double refractiveness of the transparent resin material is, thereupon, added and mixed to and with the resin layer 5. |
