| 摘要 |
PURPOSE:To improve the repetitive characteristic by increasing the temperature of a part of a recording medium to be erased to a setting temperature by a light beam of a high power density region, and erasing the recording while the setting temperature is maintained by the light beam of a low power density region to prevent the deterioration of the performance of the optical disk due to thermal damage. CONSTITUTION:Erasure is applied by using an erasure beam with a beam profile where the temperature of the recording medium is increased to the setting temperature by the light provided with a high power density region at first, and the power is decreased gradually up to the lower power density region reaching the setting temperature at the steady-state to keep the setting temperature. Thus, an amorphous recording pit is converted into the state of liquid crystal, that is, unrecorded state on the recording film to apply erasure, and the film is not subjected to extreme high temperature even with the total power fluctuated because the temperature range of the setting temperature is set to a small power. Thus, the performance deterioration in the optical disk due to thermal damage is prevented to improve the repetitive characteristic.
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