| 摘要 |
PURPOSE:To perform a crystallizing recording wide to a groove width and to obtain a high-quality signal by offsetting the operating point of a focus from a position in focus and changing a crystallizing laser beam profile and an amorphous laser beam profile. CONSTITUTION:The sigmoidal characteristic of focus control is a normal focus range 14, a normal operating point or a position in focus 15 and an offset position 16 in the case of this crystallizing recording. At the time of the normal crystallizing recording is a profile 6 and a B point is the critical temperature of crystallization. When the operating point of the focus is selected at the point shown by the 16, the laser beam becomes wider than the case in focus, the highest value of laser power lowers and it becomes a profile shown by a code 17. That is to say, a range in which the crystallization occurs widens from a conventional range shown by a code 8 to a range shown by a code 18. Thus, the crystallizing recording wide to the groove width can be performed and the high-quality signal can be obtained. |
