Patent ID: 7110343
Filing Date: 2006-09-19
Classification: G11B

Abstract:
1. An aberration correction apparatus for correcting aberration generated by reflection of a light beam reflected from a recording layer of a recording medium which is irradiated with the light beam, comprising: a first aberration correction element having a plurality of aberration correction portions and causing a phase change in a transmitting light beam upon application of voltage, a second aberration correction element which causes a phase change in a transmitting light beam such that the wave front of the transmitted light beam has a blaze hologram shape, a discriminator which receives the reflected light beam to discriminate the aberration of the reflected light beam, a coarse phase adjuster which drives the second aberration correction element on the basis of the magnitude of the aberration of the reflected light beam to perform an aberration correction, and a fine phase adjuster which adjusts the applied voltage to the aberration correction portions of the first aberration correction element to correct aberration remained after the aberration correction by the coarse phase adjuster.