Patent ID: 7414950
Filing Date: 2008-08-19
Classification: G11B

Abstract:
1. An aberration correction liquid crystal device to be mounted in an optical pickup apparatus for applying a laser beam emitted from a laser light source onto different types of optical discs, and to be disposed on an optical axis of the laser beam, the device comprising: a first electrode section to be placed on the side of the laser light source and having a first electrode pattern for correcting aberration concerning a first optical disc, the first electrode pattern being defined by a first group of electrodes; a second electrode section to be placed on the side of the optical disc and having a second electrode pattern for correcting aberration concerning a second optical disc different from the first optical disc in type, the second electrode pattern being defined by a second group of electrodes; and a liquid crystal being sandwiched between the first and the second electrode sections, wherein in correcting the aberration concerning the first optical disc, the first electrode pattern is applied with a voltage and all of the second group of electrodes are placed in equipotential state, and wherein in correcting the aberration concerning the second optical disc, the second electrode pattern is applied with a voltage and all of the first group of electrodes are placed in equipotential state.