| 摘要 |
PURPOSE:To reduce the blur of a spot by setting the power of a semiconductor laser, with which a sample area is irradiated, to intermediate power between reproducing power and recording power at the time of using a recording mode. CONSTITUTION:When the sample area is irradiated with the semiconductor laser at the time of using the recording mode, the power of the semiconductor laser is set to the intermediate power between the reproducing power and recording power. For example, at the time of the recording mode, a light flux, with which a sector is irradiated, is changed in three stages such as recording power Pw, reproducing power Pr and intermediate power Ps according to the emitting power of the semiconductor laser as a light source. In such a case, the influence of chromatic abberation to a focusing state is mutually distributed in a reverse direction to the recording power and reproducing power. Although the blur of the spot is generated to the recording power and reproducing power, the degree of the blur is reduced. |
