| 摘要 |
PURPOSE:To obtain an optical information recording medium which is capable of recording with high density and large capacity and can facilitate random access together with use of a magneto-optical recording film, by forming a head guide groove having its section of a gentle curved surface such as a semicircular or a semioval shape on the surface of a substrate. CONSTITUTION:A head guide groove 42 having its section of a curved surface such as a semicircular or semioval shape is formed spirally or concentrically on the surface of a substrate 41. Then a magneto-opical recording film 43 which is capable of optical recording, reproduction and re-recording and has an axis easy for magnetization in the direction vertical to the film surface is formed evenly on the substrate 41. The film 43 is made of an amorphous alloy containing rare earth metals such as Gd, Tb, Dy, Ho, etc. and the transition metals like Fe, Co, etc. The groove 42 has no corner part and therefore has no discontinued part since the film 43 is formed evenly on any surface of the groove 42. As a result, no anisotropy is produced and therefore an axis easy for magnification and vertical to the film surface is formed safely at any place of the film 43. Thus it is possible to detect the rotation of the plane of polarization of the reflected light of an illumination light beam which is due to the inversion of said axis in a reproduction mode. |
