Optical pickup

Abstract

In an objective lens driving means of an optical pickup, the accuracy of the boundary position of magnets is improved, the generation of angular moment through coils is suppressed, and the inclination of the objective lens is reduced. An optical pickup for reading or writing information on an optical disc using an objective lens includes a lens holder for holding an objective lens, three magnets disposed facing to each of the two sides of the lens holder that are parallel to the focusing direction and the tracking direction, and a yoke for mounting these magnets. The yoke includes a central yoke surface for mounting the central one of the three magnets, and outer yoke surfaces for mounting the outer two of the three magnets. A step is formed between the central yoke surface and each of the outer yoke surfaces.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an embodiment of an objective lens driving means of an optical pickup according to the invention.

FIG. 2 shows a yoke of the objective lens driving means shown in FIG. 1.

FIG. 3A, FIG. 3B, FIG. 3C and FIG. 3D show how the yoke and magnets of the objective lens driving means of FIG. 1 are assembled.

FIG. 4 shows the magnets of the objective lens driving means shown in FIG. 1 having different dimensions from those of FIG. 1.

FIG. 5 shows an arrangement of a yoke and magnets of an objective lens driving means different from that of the invention.

FIG. 6 shows an arrangement of a yoke and magnets of an objective lens driving means different from that of the invention.

FIG. 7 shows a block diagram of an optical disc drive according to the present invention.

Claims

1. An optical pickup for reading and writing information on an optical disc using an objective lens, comprising: a lens holder for holding an objective lens;three magnets disposed facing to each of the two sides of the lens holder that are parallel to a focusing direction and a tracking direction; anda yoke for mounting the magnets,wherein the yoke includes, for each of the two sides of the lens holder, a central yoke surface for mounting a central one of the three magnets and outer yoke surfaces for mounting the two outer magnets of the three magnets, wherein a step is formed between the central yoke surface and each of the outer yoke surfaces.

2. The optical pickup according to claim 1, wherein the outer magnets are disposed while they are abutted against their respective steps of the yoke.

3. The optical pickup according to claim 1 or 2, wherein the width of the central magnet in the tracking direction is equal to or smaller than the width of the central yoke surface of the yoke in the tracking direction, and wherein the central magnets are abutted against their respective outer magnets disposed on a diagonal with the objective lens in the center of their outer magnets.

4. The optical pickup according to any one of claims 1 to 3, wherein the thickness of the central magnet is smaller than the thickness of the outer magnets, and wherein the surfaces of the three magnets facing to the side of the lens holder parallel to the focusing direction and the tracking direction lie substantially in the same plane.