| 摘要 |
PURPOSE:To obtain a large reproducing C/N without damaging recording information by storing data of the optimum impression magnetic field at the time of reproduction and the optimum power of a laser beam for reproduction in a specific area on a disk. CONSTITUTION:By setting an impression magnetic field Hex in a direction opposite to that of a leakage magnetic field Hl at the time of reproduction and setting the magnetic field Hex at a specific range, an effective magnetic field added onto a laser illumination part is suppressed by an offset effect. Therefore, critical coercive force Hc whose recording magnetic domain deforms is decreased, and a deformation critical laser power Pc is increased, then, the C/N of a reproducing signal can be improved. And by setting reproducing laser power P less than the power Pc, the deformation of the magnetic domain can be prevented from being generated. And the optimum magnetic field Hex at the time of reproduction and the data in which the power P is tested are recorded in a read-in area 3, and it is read out at the time of reproduction, then, automatic setting is performed. In such a way, it is possible to heighten the C/N without damaging the recording information. |
