| 摘要 |
PURPOSE:To obtain a long life magnetic modulation type rewritable optical disk by using plural semiconductor lasers and heating spots of a recording film in turn at more than Curie point with a multibeam in a medium output. CONSTITUTION:The recording film 15 is irradiated in such a manner that after a laser beam 17 passes through an optical disk 1, a laser beam 18 is positioned to pass over it. A spot irradiated by the beam 17 is raised in temperature but not to reach the Curie point, and when the same spot is irradiated successively by the beam 18 it is additionally heated so as to reach the Curie point. A spot heated more than the Curie point is reduced in its coercive force of the corresponding recording film 15, and the magnetization of the recording film 15 is reversed in accordance with an external magnetic field, thus performing the recording and erasing. By this method, a long life magnetic modulation system device can be obtained with semiconductor lasers having a medium light output respectively. |
