Electromagnetic actuator and optical disk apparatus incorporating the same

An apparatus for recording/reproducing information upon an optical recording medium with a light beam, comprising:

• means for generating the light beam;
• means for converging the light beam onto the optical recording medium;
• means for movably suspending the converging means;
• means for carrying the suspending means;
• and
• first and second magnetic circuits for generating first driving force for moving the carrying means in a first direction and second driving force for moving the suspending means in a second direction perpendicular to the first direction, the first and second magnetic circuit being separately arranged and the carrying means located between the first and second magnetic circuits;
• each of the magnetic circuit including:
• a first magnetic yoke having first and second flat surfaces and a first side surface;
• first permanent magnets for generating first magnetic fluxes, which are separately fixed on the first flat surface of the first yoke;
• plurality of second permanent magnets for generating second magnetic fluxes, which are separately fixed on the second flat surface of the first yoke;
• a second magnetic yoke having a second side surface and a flat surface faced to the first flat surface of the first yoke with a first magnetic gap between the first permanent magnets, and fixed on the first permanent magnets, the first magnetic fluxes being guided to the first magnetic gap through the first and second magnetic yokes;
• a third magnetic yoke having a third side surface and a flat surface faced to the second flat surface of the first yoke with a second magnetic gap between the second permanent magnets, and fixed on the second permanent magnets, the second magnetic fluxes being guided to the second magnetic gap through the first and third magnetic yokes;
• third, fourth and fifth permanent magnets generating third magnetic fluxes, which are fixed to the side surfaces of the first, second and third magnetic yokes, respectively;
• first coil fixed to the carrying means and extending in the first and second gaps, in which a first current is supplied;
• and
• second and third coil fixed to the suspending means and faced to the third, fourth and fifth permanent magnets with a traveling space along the first direction, in which a second current is supplied, a first driving force causing the first unit to move in the first direction being generated due to an interaction between the first current and the first, second and third magnetic fluxes penetrating the first coil in the first and second gaps and the traveling space, and a second driving force causing the second unit to move in the second direction being generated due to an interaction between the second current and the third magnetic fluxes penetrating the second and third coils in the traveling space.