| 摘要 |
PURPOSE:To use a low-output laser, to make it long-lived and to simplify an optical head by providing a heater to preheat a medium before the convergence spot of a semiconductor laser beam for recording and erasing. CONSTITUTION:A laser beam 32 irradiating from an optical head 21 is converged on a medium as the spot. When recording or erasing, a heater 31 provided ahead of the convergence spot of the beam 32 in the direction of the rotation of the medium 6. Next, the temperature is raised to a temperature at which the recording and erasing of the medium 6 is attained by the convergence spot. When the temperature of the medium 6 rises to the prescribed temperature, the direction of a magnetic force line 34 is changed by an electromagnet 27 and thus, the recording and erasing are performed. By preheating the medium before the convergence spot like this, the low-output laser can be used, it is made long-lived, it is unnecessary to use to lasers and the optical head is simplified. |
