Optical Pick-up Apparatus
AssigneeKonica Corporation
InventorsTohru Kimura, Kohei Ota
Life of this patent
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Abstract
An optical pickup apparatus for conducting recording and/or reproducing information of an optical information recording medium, comprises a light source; a converging optical system having an objective lens; and a photo-detector. The converging optical system comprises a plastic lens and a spherical aberration deviation correcting element to correct deviation of a spherical aberration of the converging optical system. A numerical aperture of the objective lens at an image-side is 0.65 or more.
Claims48
An optical pickup apparatus for conducting recording and/or reproducing information of an optical information recording medium, comprising:
- a light source;
- a converging optical system to converge light flux emitted from the light source on an information recording plane of the optical information recording medium so as to conduct reproducing and/or recording information of the optical information recording medium, the converging optical system having an objective lens;
- and
- a photo-detector to receive reflected light flux from the information recording plane;
- wherein the converging optical system comprises at least a plastic lens and a spherical aberration deviation correcting element to correct deviation of a spherical aberration of the converging optical system and a numerical aperture of the objective lens at an image-side is 0.65 or more.
An optical information recording medium recording and/or reproducing apparatus for conducting recording and/or reproducing information of an optical information recording medium, comprising:
- an optical pickup apparatus comprising:
- a light source;
- an converging optical system to converge light flux emitted from the light source on an information recording plane of the optical information recording medium so as to conduct reproducing and/or recording information of the optical information recording medium, the converging optical system having an objective lens;
- and
- a photo-detector to receive reflected light flux from the information recording plane;
- wherein the converging optical system comprises at least a plastic lens and a spherical aberration deviation correcting element to correct deviation of a spherical aberration of the converging optical system and a numerical aperture of the objective lens at an image-side is 0.65 or more.
A spherical aberration deviation correcting element for use in an optical pickup apparatus for recording and/or reproducing information of the optical information recording medium, comprising:
- a positive lens group having at least a positive lens;
- and
- a negative lens group having at least a negative lens, wherein at least one of the positive lens group and the negative lens group is a movable element movable in a direction of an optical axis and the movable element can change the slope angle of the marginal ray of an exit light flux by moving in a direction of the optical axis, and wherein each positive lens of the spherical aberration deviation correcting element has Abbe's numbers of 70 or less or each negative lens of the spherical aberration deviation correcting element has Abbe's numbers of 40 or more and the spherical aberration deviation correcting element comprise at least a diffractive surface having a ring-shaped diffractive structure.
Dependencies are inferred from the claim text.