| 摘要 |
PROBLEM TO BE SOLVED: To prevent the splashing of optical recording layer components and to enable a higher density and higher speed access by determining the thicknesses of a magnetic layer consisting of ferromagnetic metallic powder and binder disposed on one surface of a base and an optical recording layer disposed on the other surface in respective spectacle ranges and having a protective layer contg. inorg. material of a specific hardness range on this optical recording layer. SOLUTION: The thickness of the magnetic layer is determined in a range of 0.05 to 2 μm, preferably 0.07 to 1.5 μm, further preferably 0.1 to 1.0 μm and the thickness of the optical recording layer in 0.05 to 1 μm, preferably 0.1 to 0.8 μm, further preferably 0.2 to 0.5 μm. These thicknesses are specified in the ranges described above, by which the contact with a recording medium head is improved and the occurrence of head clogging, etc., is averted. The protective layer disposed on the optical recording layer contains the inorg. material of Mohs hardness of 6 to 8 and this inorg. material is disposed on the optical recording medium layer by coating thereof together with the binder or only the inorg. material is deposited on the optical recording layer. |
