Patent ID: 7054078
Filing Date: 2006-05-30
Classification: G11B

Abstract:
1. An objective lens driving device comprising: a lens holder including an objective lens for condensing a light emanated from a light source onto an optical disk medium, a focusing coil for driving the objective lens in a light axis direction, a tracking coil for driving the objective lens in a radial direction, and tilt coils for driving the objective lens in a rotational direction within a plane including two axes of said light axis direction and said radial direction; a fixed block for supporting said lens holder by supporting members of supporting said lens holder; focusing and tracking magnets for generating an electromagnetic force acting on said focusing coil and said tracking coil; tilt magnets for generating an electromagnetic force acting on said tilt coils; wherein said tilt coils are wound in a multilayer and has an inner peripheral shape of a substantial rectangle, said tilt coils being mounted on opposite side surfaces of said lens holder in the radial direction, wherein said tilt magnets are located to put said lens holder between said tilt magnets in the radial direction and to oppose to said tilt coils, respectively, each of said tilt magnets being divided into two parts in a direction parallel to said light axis direction, said two parts being magnetized to have different polarities in the radial direction, respectively, and wherein when said lens holder is in a neutral position, a ratio of a gap between opposing surfaces of one tilt magnet and one tilt coil which oppose to each other, to a radial direction thickness of the tilt magnet, is in the range of 1/1.5 to 1/3.