Patent ID: 6914865

Claim:
An optical pickup, comprising: a light emitting unit used for emitting light, an object lens used for collimating the light from the light emitting unit to form a beam of light and focusing the beam of light to a recording surface of an optical disc, and a correction unit used for correcting an aberration caused by a tilt of an optical axis of the beam of light relative to the recording surface of the optical disc, wherein said correction unit has a light transmitting surface capable of allowing a transmission of the light from the light emitting unit, with a plurality of electrodes arranged on a plurality of divided areas of the light transmitting surface, said correction unit correcting the aberration by applying voltages, corresponding to said tilt of the optical axis of the beam of light relative to the recording surface of the optical disc, to said electrodes and changing phases of the bean of light passing through the divided areas of the light transmitting surface, said electrodes consisting of: a first electrode arranged on at least one area of the light transmitting surface of said correction unit at a position maximizing an aberration, caused by a radial tilt of the optical axis of the beam of light relative to the recording surface of the optical disc in a radial direction of the disc; and a second electrode arranged on at least one area of the light transmitting surface of said correction unit at a position minimizing the aberration, caused by the radial tilt of the optical axis of the beam of light relative to the recording surface of the optical disc, and a summed length of said first and second electrodes in the radial direction of the optical disc ranges from 50% to 70% of a diameter of said object lens, and a length of said first or second electrode in a tangential direction of the optical disc ranges from 40% to 50% of the diameter of said object lens.