US Patent 7256926 Optical deflector

An optical deflector includes a magnet unit, which generates a magnetic field, and a movable plate unit, which is placed in the magnetic field. The movable plate unit has an inner movable plate having a reflecting surface, an outer movable plate, two inner torsion bars connecting the inner and outer movable plates, a support located outside the outer movable plate, and two outer torsion bars connecting the outer movable plate and support. The movable plate unit has two inner drive wiring portions that extend along by a periphery of the inner movable plate. The magnet unit includes magnets, two adjacent magnets of which are opposite in magnetic polarity direction. The inner drive wiring portions extend almost parallel to boundaries between the two adjacent magnets and are respectively located substantially immediately above the boundaries. Currents of the same direction are applied to the two inner drive wiring portions.