Patent ID: 6587284
Filing Date: 2003-07-01
Classification: G11B

Abstract:
An objective lens driving apparatus comprising:an objective lens (1) for focusing a light beam on a disc for recording and reproducing information on said disc; a lens holder (2) for holding said objective lens; a plurality of supporting members (3a-3d) for supporting said lens holder so as to be movable in a focusing direction (Fo) of the optical axis direction of said objective lens, and also in a tracking direction (Tk) of a radial direction of said disc; a coil assembly (4a) having a focusing coil (5a) formed so as to include a line of intersection of the plane of the focusing coil and the plane being perpendicular to the tracking direction (Tk) and including the optical axis of said objective lens as a center line and at least two tracking coils (46-49) arranged on both sides of said focusing coil symmetrically to a center line being parallel to said tracking direction of said focusing coil and aligned in a direction normal to said center line on a plane including the focusing direction and the tracking direction of said lens holder; and a magnet assembly (8a) including: a first magnet (8a1), disposed opposite to said focusing coil, edges of said first magnet extending parallel to said focusing direction passing through the centers of said tracking coils facing one-half region of each of said tracking coils, said first magnet having magnetic poles arranged at positions opposite to winding portions of said focusing coil extending in a direction intersecting said focusing direction; and a second magnet (8a2) disposed so as to face the remaining one-half region of each of said tracking coils, and having magnetic poles arranged at positions opposite to winding portions of said tracking coils extending in a direction intersecting said tracking direction.