Objective lens for optical pickup and optical pickup apparatus having the same
AssigneeSamsung Electronics Co., Ltd.
InventorsSeong-su Park, Soo-han Park, Woo-chang Chun
Life of this patent
Estimating the term…
Abstract
An objective lens for optical pickup and an optical pickup apparatus having the same are provided. The objective lens for optical pickup includes a light source side lens surface and a disc side lens surface. The light source side lens surface and the disc side lens surface each include an effective region disposed at a central region of the objective lens and a non-effective region disposed outside the effective region. An optical path changing element, disposed in the non-effective region of at least one of the light source side lens surface and the disc side lens surface, changes a path of light incident thereon.
Claims20
An objective lens for optical pickup, comprising:
- a light source side lens surface and a disc side lens surface,
- wherein the light source side lens surface and the disc side lens surface each comprise an effective region, which is disposed at a central region of the objective lens, and a non-effective region which is disposed outside the effective region, and
- an optical path changing element, disposed in the non-effective region of at least one of the light source side lens surface and the disc side lens surface, which changes a path of light incident thereon;
- wherein a distance between a focal point of light incident on the non-effective region and the focal point of light incident on the effective region is dx1, a distance from a surface of the disc to a deepest recording layer of the disc is Dmax, a distance from the surface of the disc to a most shallow recording layer of the disc is Dmin, and the distance dx1 is within a range represented by the following formula:
- 2×Dmax−Dmin+10 μm≦dx1≦600 μm.
An optical pickup apparatus, comprising:
- a light source which generates light for recording information on a disc or reproducing information from the disc;
- an objective lens which focuses light from the light source onto the disc, the objective lens comprising a light source side lens surface and a disc side lens surface,
- wherein the light source side lens surface and the disc side lens surface each comprise an effective region, disposed at a central region of the objective lens, and a non-effective region, disposed outside the effective region;
- and
- an optical path changing element, disposed in the non-effective region of at least one of the light source side lens surface and the disc side lens surface, which changes a path of light incident thereon;
- wherein a distance between a focal point of light incident on the non-effective region and the focal point of light incident on the effective region is dx1, a distance from a surface of the disc to a deepest recording layer of the disc is Dmax, a distance from the surface of the disc to a most shallow recording layer of the disc is Dmin, and the distance dx1 is within a range represented by the following formula:
- 2×Dmax−Dmin+10 μm≦dx1≦600 μm.
Dependencies are inferred from the claim text.