| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent such the situation that fine adjustment is not performed appropriately by performing the coarse adjustment of a spherical aberration correction value with a tracking error signal amplitude value as an evaluation index, which is performed prior to the fine adjustment of spherical aberration correction value-focus bias. <P>SOLUTION: An optimum (e,g, a TE amplitude value is made the maximum) astigmatism correction value is searched in a state in which the spherical aberration correction value-focus bias are fixed based on the result in which the amplitude value of the tracking error signal TE obtained when the astigmatism correction value is changed is obtained, and astigmatism correction is performed by the correcting value. Thereby, a reproduction performance optimum point and a tracking performance optimum point of the focus bias-spherical aberration correction value can be approached so as to coincide, appropriate fine adjustment is performed based on the coarse adjustment result. <P>COPYRIGHT: (C)2009,JPO&INPIT |
