| 摘要 |
PURPOSE:To perform stable tracking reproducing on a magnetic disc without pregroups by recording information on an information medium, where a magnetic thin film magnetized preliminarily in one direction is vapor-deposited, while applying a magnetic field in the direction opposite to the direction of this magnetization of the thin film. CONSTITUTION:When a magnetic thin film 38 is irradiated with a laser beam 39 modulated by an information signal, a bubble row 41 where magnetization is inverted is generated in accordance with the level of the signal. When a laser beam 40 having a certain intensity is irradiated to a part slightly distant from the bubble row 41 simultaneously with the irradiation of the laser beam 39, magnetization is inverted continuously to record a continuous track 42. A pitch is so set that a gap 44 is provided between the bubble row 41 and a next signal track 43 generated by one rotation of the magnetic disc. Consequently, the original magnetization row which is directed upward remains in the gap 44 between signal tracks as it is. In case of reproducing, the beam 39 is irradiated to the signal row 41, and beams 40 and 45 are irradiated to tracks 42 and 44, their reflected lights are detected as a change of the intensity of light after passing a polarizing plate. |
