Patent ID: 7643386
Filing Date: 2010-01-05
Classification: G11B

Abstract:
1. An optical pickup actuator comprising: a lens holder comprising an object lens for focusing a laser beam onto an optical information storage medium, the lens holder being movably supported by a support member and having a coil mounting portion with a closed upper side being mounted therein; and a magnetic circuit driving the lens holder in a focusing direction and a tilt direction independently; wherein the magnetic circuit comprises: a focusing coil disposed in an inner wall of the coil mounting portion of the lens holder; a pair of tilt coils disposed in the inner wall of the coil mounting portion of the lens holder and being overlapped with the focusing coil in the focusing direction and driven independently; a plurality of track coils supported by the lens holder to drive the lends holder in the track direction independently; an inner yoke disposed inside the focusing coil and the tilt coils; an outer yoke disposed outside the focusing coil and the tilt coils; and a magnet part generating a driving force in the focusing direction due to an interaction with the focusing coil and generating a driving force in the tilt direction due to an interaction with the tilt coils; wherein the magnet part comprises a pair of single-pole magnets facing to each other with respect to the lens holder, the single-pole magnets generating an electromagnetic force in the track direction at the neighboring sides of the track coil in the focusing direction; and wherein the outer yoke encloses an outer side of each single-pole magnet which is exposed in the track direction, to generate a magnetic flux in an opposite direction to a direction of magnetic flux of the single-pole magnets.