| 摘要 |
<P>PROBLEM TO BE SOLVED: To satisfactorily correct spherical aberration, and efficiently correct astigmatism caused by the correction of spherical aberration. <P>SOLUTION: An optical pickup 12 includes: a laser light source 14 which can emit blue laser; an objective lens 10 which the blue laser emitted from the laser light source 14 enters; and a liquid crystal element 1 provided on an optical path of the blue laser emitted from the laser light source 14 and between the laser light source 14 and the objective lens 10. The liquid crystal element 1 has, on one surface thereof, a spherical aberration correction electrode group 5 including at least nine concentric electrodes 5a-5i, and on the other surface thereof, an astigmatism correction electrode group 6 including a plurality of electrodes 6a-6h for correcting astigmatism caused by the correction of spherical aberration, where the electrodes 6a-6h have a shape obtained by dividing a circle with dividing lines extending in radial directions. <P>COPYRIGHT: (C)2011,JPO&INPIT |
