| 摘要 |
PURPOSE:To enlarge a recordable region, facilitate the size reduction of a driving device and improve portability by a method wherein chucking is applied to the outer circumferential part of a disc-shaped substrate on which a recording medium layer is provided to eliminate a sensing hub which is normally required. CONSTITUTION:When a recording medium layer 3 is formed on the surface of a disc-shaped substrate 2, a hole is not formed at the center part of the substrate 2. The substrate 2 is made of material having excellent optical characteristics such as polycarbonate, acrylic resin or glass and the recording agent of the medium 3 is selected in accordance with the wavelength of employed laser beam. For instance, if the substrate is composed of an organic thin film, azo pigment, methylene pigment, etc., is employed and dichloroethane, methylethylketone, etc., is employed as recording medium solvent. Further, an abrasion--resistant layer 4 which is made of compound plastic, metal oxide, etc., and provides a contact with a driving device 5 is formed on the circumferential part of the substrate 2. For instance, the layer 4 is made of ultraviolet-cured aromatic polyamide fibers, Al2O3, etc. Then the layer 4 is driven by a circular piezoelectric ceramics 6 provided in the device 5. |
