Patent ID: 7102966

Claim:
A lens actuator comprising: a lens holder to support an objective lens, said lens holder having a pair of first side surfaces in a tracking direction and a pair of second side surfaces in a tangential direction; wire springs, provided on the first side surfaces of the lens holder, to support the lens holder; a pair of fixed magnets disposed to confront the second side surfaces of the lens holder, each of the magnets having four regions which are defined by mutually perpendicular first and second magnetic boundary lines and have approximately the same area and are magnetic, such that magnetic directions of the four regions are perpendicular to a plane including a focusing direction and the tracking direction but are in opposite directions between two mutually adjacent regions, said first magnetic boundary line extending in the focusing direction, said second magnetic boundary line extending in the tracking direction; a pair of yokes having a predetermined thickness and having the corresponding magnets fixed thereon; first coils disposed between each second surface of the lens holder and each magnet and arranged on both sides of the first magnetic boundary line along the second magnetic boundary line of each magnet, said first coils being arranged symmetrically with respect to an optical axis of the objective lens; and second coils disposed between each second surface of the lens holder and each magnet and arranged on both sides of the second magnetic boundary line along the first magnetic boundary line of each magnet, said second coils being arranged symmetrically with respect to the optical axis of the objective lens, a first pair of diagonally arranged first coils generating thrusts in the same direction and a second pair of diagonally arranged first coils generating thrusts in mutually opposite directions, in response to power supplied independently thereto.