| 摘要 |
PURPOSE: An actuator for optical pickup is provided to minimize a phase change of an objective lens by changing moment of force to affect to driving part and to be generated from a coil of the outside of effective magnetic space. CONSTITUTION: A driving part of asymmetric conformation is formed centering on a lens. Driving force of a driving part is generated from a magnetic circuit which is composed of a permanent magnet(46), a yoke(48) and a coil. A sub-coil is located at around the magnetic circuit. A magnetic flux control member controls leakage flux to be generated from the magnetic circuit and to cross the sub-coil. The magnetic flux control member is cap member which shields an opening part formed at the upper side of the yoke. A lens protrusive actuator is divided into the driving part to include an objective lens, a bobbin, a tracking coil, a focusing coil(52) and a wire spring and a fixing part to include the permanent magnet(46), the yoke(48), a cap(58), and a frame. The magnetic flux generated from the permanent magnet(46) crosses the main focusing coil(52a) and the tracking coil, and generates driving force of a focusing direction and a tracking direction while its part is leaked toward a sub-focusing coil(52b).
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