| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve efficiency in preparation work for correcting spherical aberration included in return light from a multilayer optical disk by carrying out the preparation work easily and speedily. <P>SOLUTION: An optical disk inspection device continuously displaces an objective lens 26 from a lower limit position toward an upper limit position within a displaceable range with an objective lens movement signal output from an objective lens movement signal generation circuit 56, and calculates respective distances D1, D2, and D3 from the surface L0 of a cover layer to respective recording layers L1, L2, and L3 using a focus-error signal at the displacement of the objective lens 26. Then, spherical aberration correction quantities R1, R2, and R3 according to the respective distances D1, D2, and D3 are memorized respectively. In reproducing a signal from an optical disk DK, spherical aberration is corrected by controlling the position of a convex lens 24a using the spherical aberration correction quantities R1, R2, and R3 corresponding to a recording layer in which an optical spot is formed. <P>COPYRIGHT: (C)2007,JPO&INPIT |
