US 2003/0193877 A1 · Recording/reproducing apparatus having an optical pickup device to read from and record information to disks of different thicknesses

Abstract

A recording/reproducing apparatus having an optical pickup device which is efficient in light use having little spherical aberration. The recording and/or reproducing apparatus includes an optical pickup having an objective lens, disposed opposite a disk, having a light passing region divided into central, intermediate and periphery regions corresponding to a near axis area, an intermediate axis area and a far axis area of incident light, where the curvature of the central and peripheral regions is optimized for a thin disk and that of the intermediate region is optimized for a thick disk, a light source irradiating light toward a disk through the objective lens; a photo detector for detecting light reflected from the disk, and a beam splitter, disposed between the objective lens and the light source, for transmitting light from the light source toward the objective lens and for diffracting light reflected from the disks toward the photo detector; and a processing unit to process an information signal to control the incident light generated by the light source, and to process the detected light from the photodetector. Therefore, the optical pickup device can be used for both compact disks (CDs) that are thick using light beam passing the near and intermediate regions of said objective lens, and digital video disks (DVDs) that are thin using light beam passing the near and far axis regions of said objective lens, and detect signals without picking up noise regardless of the thickness of the disk.

Claims16

Dependent claims

An objective lens for use with disks of different thicknesses, comprising:

a first region having an optical characteristic useable with recording and/or reproducing data with respect to a plurality of the disks independent of the thickness;
and
a second region having an optical characteristic useable with recording and/or reproducing data with respect to less than all of the plurality of disks having different thicknesses.

An objective lens to form beam spots of first and second sizes on first and second recording media using corresponding first and second light beams, the objective lens comprising:

an inner region including an optical center of the objective lens which has an optical property to focus the first light beam onto the first optical recording medium of a first thicknesses and to focus the second light beam onto the second optical recording medium of a second thickness other than the first thickness;
and
a second region surrounding said inner region and comprising an optical property optimized so as to selectively direct the first and second light beams so as to change a numerical aperture of the objective lens and to form the first and second light spots on the corresponding first and second recording media.

Dependencies are inferred from the claim text.

Recording/reproducing apparatus having an optical pickup device to read from and record information to disks of different thicknesses

Life of this patent

Recording/reproducing apparatus having an optical pickup device to read from and record information to disks of different thicknesses

Life of this patent

Abstract

Claims16