High NA objective lens for optical pick-up
AssigneeAsahi Kogaku Kogyo Kabushiki Kaisha
InventorKoichi Maruyama
Life of this patent
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Abstract
A single-element objective lens is employed in an optical pick-up. The objective lens directs an incident light beam to a data recording surface of an optical disc through a cover layer to form a beam spot thereon. A numerical aperture of the objective lens is 0.7 or more. The objective lens is configured such that a characteristic of aberration which is generated due to decentering of surfaces of the objective lens is substantially comparable to a characteristic of aberration due to an inclination of an optical axis of the objective lens and an inclination of a central axis of the light beam incident on the data recording surface of the optical disc with respect to the optical disc.
Claims12
A single-element objective lens for an optical pick-up, said objective lens directing an incident light beam to a data recording surface of an optical disc through a cover layer to form a beam spot, a numerical aperture of said objective lens being 0.7 or more,
- said objective lens being configured such that a characteristic of aberration due to decentering of surfaces of said objective lens is substantially comparable to a characteristic of aberration due to an inclination of an optical axis of said objective lens and a central axis of the light beam incident on the data recording surface of the optical disc with respect to the optical disc.
An optical pick-up, comprising:
- a laser source that emits a laser beam;
- a single-element objective lens, said objective lens directing the laser beam emitted by said laser source to a data recording surface of an optical disc through a cover layer to form a beam spot, a numerical aperture of said objective lens being 0.7 or more;
- and
- an inclination adjusting mechanism which adjusts an inclination of an optical axis of said objective lens and a central axis of the laser beam Incident on the cover layer with respect to the optical disc,
- wherein said objective lens is configured such that a characteristic of aberration due to decentering of surfaces of said objective lens is substantially comparable to a characteristic of aberration due to an inclination of an optical axis of said objective lens and a central axis of the light beam incident on the data recording surface of the optical disc with respect to the optical disc.
Dependencies are inferred from the claim text.