| 摘要 |
PURPOSE:To improve recording density and transfer speed by forming the films of a recording layer which is subjected to recording or reproducing by light signals and a protective layer on a hollow cylindrical substrate surface consisting of a transparent material. CONSTITUTION:This recording medium 1 is formed by using the transparent material such as plastics formed to a cylindrical shape as the substrate 4 and forming the recording layer 5, the protective layer 6, and an over coat layer 7 successively on the outside surface thereof. Optical recording or reproducing is executed by using such cylindrical medium for optical recording and reproducing and causing the medium to be irradiated by light from the surface of the substrate 4 on the side where the recording layer 5 and the protective layer 6 are not formed. Since the recording medium is irradiated by the light through the substrate 4, the degradation in the reliability of recording by dust and dirt is obviated. Since the substrate 4 is cylindrical, the required area per information unit is equally set in the respective parts of the recording medium and the efficient recording is executed. The efficient recording with the high reliability, recording density and information transfer speed is thus executed. |
