| 摘要 |
<P>PROBLEM TO BE SOLVED: To perform spherical aberration correction using a spherical aberration detection method which does not utilize a reproduction signal from a medium and a detection result concerned. <P>SOLUTION: An optical disk drive which performs correction of spherical aberration is provided with: a means which receives a laser beam reflected from an optical disk by a light receiving section that has been divided into a plurality of concentric circles; a means to calculate spherical aberration information from focus position information on each divided light receiving section; a polarizing surface division polarization means which is surface divided in shapes of a plurality of concentric circles; a liquid crystal polarization means which performs polarization control based on the spherical aberration information; and a liquid crystal polarizing plate control means which switches the above liquid crystal polarization means by changing a control potential and a control determination period according to liquid crystal neighborhood temperature. <P>COPYRIGHT: (C)2007,JPO&INPIT |
