Patent ID: 7907498

Claim:
An optical pickup comprising: a light source to emit a light beam of a predetermined wavelength; an objective lens to focus the light beam emitted from the light source onto the signal recording surface of an optical disk; a liquid-crystal optical element provided between the light source and objective lens to correct spherical aberration, astigmatism and coma by varying a refractive index of the liquid-crystal optical element; and a photodetector to detect return light from the signal recording surface of the optical disk, the liquid-crystal optical element having a pair of electrodes disposed opposite to each other in the optical-axial direction; and the liquid-crystal optical element having a pattern to correct spherical aberration, a pattern to correct astigmatism and a pattern to correct coma, the patterns being disposed dispersedly on the pair of electrodes to divide the electrode pair into a plurality of zones, and the plurality of zones resulting from division of the electrode pair by the patterns being used in combination to correct the spherical aberration, astigmatism and coma, wherein one of the pair of electrodes has a first pattern that divides the one electrode into a plurality of zones to correct spherical aberration and a second pattern disposed outside the first pattern to correct astigmatism; and the other electrode has a third pattern that divides the other electrode into a plurality of zones to correct spherical aberration and a fourth pattern disposed outside and inside the third pattern to correct coma.