Patent ID: 6778485
Filing Date: 2004-08-17
Classification: G02F,G11B

Abstract:
An optical storage device comprising:a light source; an irradiation optical system for leading light emitted from said light source to condense on a predetermined optical storage medium; a photo detector for picking up a signal light carrying information stored in said optical storage medium to read the information, said signal light being condensed onto said optical storage medium and reflected on said optical storage medium; a pick-up optical system for leading said signal light to said photo detector; a liquid crystal device having first and second liquid crystal layers disposed in an optical path of said irradiation optical system and extending in parallel with a direction intersecting said optical path, a plurality of first electrodes for driving said first liquid crystal layer, said plurality of first electrodes extending in a predetermined x-direction intersecting said optical path and arranged in a y-direction intersecting both said optical path and said x-direction, and a plurality of second electrodes for driving said second liquid crystal layer, said plurality of second electrodes extending the y-direction and arranged in the x-direction; a &lgr;/2 plate between said first and second liquid crystal layers; and a liquid crystal driver for applying controlled voltages to said plurality of first electrodes and said plurality of second electrodes of said liquid crystal device to correct an aberration of light to be condensed on said optical storage medium; wherein said irradiation optical system is an optical system which permits light beams emitted from said light source to pass through said liquid crystal device on a reciprocation basis while the light beams are condensed on said optical storage medium, and said first and second liquid crystal layers of said liquid crystal device have a thickness such that phases of light emitted from said light source passing through said first and second liquid crystal layers one time vary between 0 and &pgr; under control of voltages applied to said first electrodes and said second electrodes, respectively.