Optical pickup, aberration correction unit and astigmatism measurement method
AssigneePioneer Electronic Corporation
InventorsMasakazu Ogasawara, Yoshitsugu Araki, Sakashi Ootaki, Junichi Furukawa, Kiyoshi Tateishi
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Abstract
An optical pickup includes: a light source, an object lens, and an aberration correction unit for correcting aberration by giving a phase difference to a light beam. The aberration correction unit corrects astigmatism caused by an optical system of the optical pickup.
Claims28
An optical pickup comprising:
- a light source for emitting a light beam;
- an object lens for processing the light beam from the light source;
- and
- aberration correction means for correcting aberration by giving a phase difference to the light beam, said aberration correction means correcting astigmatism caused by an optical system of said optical pickup, said aberration correction means having an area substantially corresponding to a wave front aberration distribution of the astigmatism, optical properties of the area being changed so as to cancel the astigmatism.
An aberration correction unit for giving a phase difference to a light beam emitted from a light source and applied through an object lens to a recording medium, thereby correcting aberration, said aberration correction unit comprising:
- an electrode including a plurality of division electrodes corresponding to a plurality of division areas through which the light beam passes and which are divided in accordance with a distribution of astigmatism caused by an optical system,
- wherein a voltage is applied to each division electrode provided in each division area in response to directionality of the astigmatism so that a phase difference is given to the light beam passing through each division area in response to change in the voltage for correcting the astigmatism.
An astigmatism detection method, for an aberration correction unit in which an area through which a light beam emitted from a light source and applied through an object lens to a recording medium passes is divided into a plurality of division areas corresponding to a distribution of astigmatism caused by an optical system, and an electrode to which a voltage is applied is provided in each division area, said astigmatism detection method comprising the steps of:
- adjusting a drive pattern of the division areas and the voltage applied to each electrode;
- and
- detecting a direction and size of the astigmatism.
A aberration correction method comprising the steps of:
- preparing an electrode through which a light beam passes, said electrode including a plurality of division electrodes;
- applying voltage to said division electrodes in accordance with a distribution of astigmatism so as to give a phase difference to the light beam, to thereby correct the astigmatism.
An optical pickup comprising:
- a light source for emitting a light beam;
- an object lens for processing the light beam from the light source;
- and
- an aberration correction unit correcting aberration by giving a phase difference to the light beam, said aberration correction unit correcting astigmatism caused by an optical system of said optical pickup, said aberration correction unit having an area substantially corresponding to a wave front aberration distribution of the astigmatism, optical properties of the area being changed so as to cancel the astigmatism.
Dependencies are inferred from the claim text.