Patent ID: 6804186
Filing Date: 2004-10-12
Classification: G11B

Abstract:
An optical pick-up composed of an objective lens and a liquid crystal element in combination, for recording and reproduction of optical discs having different recording densities,the liquid crystal element having five zones in total, including: zones 2, 4 located in center parts of half circles of a small diameter beam for a low density optical disc, zones 3, 5 laid along the outer peripheries of the zones 2, 4 within the half circles, respectively, so as to surround the zones 2, 4, respectively, and a first zone which is a remaining zone other than the zones 2, 3, 4, 5 and including a diameter, wherein the direction of the diameter included in the first zone 1 is at right angles to a tilt direction to be corrected.