Patent ID: 7193937

Claim:
An objective lens driving device comprising: an objective lens for focusing a light beam on a disk; a lens holder for holding the objective lens; a support for supporting the lens holder with respect to a fixing portion in a manner translatable in a focusing direction and a tracking direction and rotatable in a radial tilting direction; and a driving system for driving the lens holder along three axes of the focusing direction, the tracking direction and the radial tilting direction, the driving system comprising two focusing coils that are each wound in a substantially rectangular toroidal shape around a winding axis parallel with an optical axis direction of the objective lens, a tracking coil that is wound around a winding axis parallel with a circumferential direction of the disk and attached to outer surfaces of the focusing coils, a first magnet that has a magnetic pole direction parallel with the circumferential direction of the disk and is arranged inside one of the focusing coils, a second magnet that has a magnetic pole direction opposite to that of the first magnet and is arranged inside the other focusing coil, a third magnet and a fourth magnet that are arranged facing the first magnet and the second magnet respectively while forming a magnetic gap such that the tracking coil and the focusing coils are located in the magnetic gap, a first yoke that is located outside the magnetic gap and holds the first magnet, a second yoke that is located outside the magnetic gap and holds the second magnet, and a bridging yoke for connecting an open end of the first yoke and an open end of the second yoke.