Pickup device and recording medium drive unit

A recording medium drive unit including a pickup device,

• wherein the pickup device comprises:
• a fixed portion;
• a movable portion holding an objective lens and adapted to move in at least one direction of a focus direction along an optical axis of a light beam incident on the objective lens and a tracking direction substantially orthogonal to the focus direction;
• a linear resilient member with ends connected to the movable portion and the fixed portion;
• a coil, wherein only one lateral side of the movable portion is attached to the coil;
• and
• a flux providing unit providing a magnetic flux that generates respective driving forces on a plurality of driven coil portions positioned away from a center of gravity of the movable portion,
• the directions of the driving forces being non-parallel and crossing with each other such that respective torques generated on the movable portion by driving the driven coil portions counteract one another;
• wherein the plurality of driven coil portions are located on the same side of a plane passing through the center of gravity of the movable portion and extending, parallel to the one lateral side, in a direction in which the movable portion is driven;
• and
• wherein the flux providing unit includes:
• a first magnet having a first pole and a second pole with different polarities and disposed opposite to the coil, the first magnet being spaced apart from the coil;
• and
• a second magnet disposed adjacent to the first magnet in such a manner that a second pole thereof is positioned close to the first pole of the first magnet opposing the coil and a first pole thereof is positioned close to the second pole of the first magnet opposing the coil,
• the coil including a tracking coil and being provided on the one lateral side of the movable portion, facing the fixed portion;
• wherein the first magnet has a first opposing surface facing the one lateral side of the movable portion and the second magnet has a second opposing surface facing a side of the movable portion that is perpendicular to the one lateral side of the movable portion, and
• wherein the first magnet and the second magnet are disposed with the first opposing surface and the second opposing surface being perpendicular to each other.

A pickup device comprising:

• a fixed portion;
• a movable portion holding an objective lens and adapted to move in at least one direction of a focus direction along an optical axis of a light beam incident on the objective lens and a tracking direction substantially orthogonal to the focus direction;
• a linear resilient member with ends connected to the movable portion and the fixed portion;
• a coil, wherein only one lateral side of the movable portion is attached to the coil;
• and
• a flux providing unit providing a magnetic flux that applies respective driving forces to a plurality of driven coil portions located at respective positions located away from a center of gravity of the movable portion,
• the directions of the driving forces being non-parallel and crossing with each other such that respective torques generated on the movable portion by driving the driven coil portions counteract one another;
• wherein the plurality of driven coil portions are located on the same side of a plane passing through the center of gravity of the movable portion and extending, parallel to the one lateral side, in a direction in which the movable portion is driven;
• and
• wherein the flux providing unit includes:
• a first magnet having a first pole and a second pole with different polarities, the first magnet facing the coil;
• and
• a yoke disposed adjacent to the first magnet, the yoke including:
• a first yoke portion in which a second pole thereof with a polarity opposite to the first pole of the first magnet is positioned close to the first pole of the first magnet opposing the coil;
• and a second yoke portion in which a first pole thereof with a polarity opposite to the second pole of the first magnet is positioned close to the second pole of the first magnet opposing the coil,
• wherein the first magnet has a first opposing surface facing the one lateral side of the movable portion and the yoke has a second opposing surface facing a side of the movable portion that is perpendicular to the one lateral side of the movable portion, and
• wherein the first magnet and the yoke are disposed with the first opposing surface and the second opposing surface being perpendicular to each other.

A recording medium drive unit including a pickup device,

• wherein the pickup device comprises:
• a fixed portion;
• a movable portion holding an objective lens and adapted to move in at least one direction of a focus direction along an optical axis of a light beam incident on the objective lens and a tracking direction substantially orthogonal to the focus direction;
• a linear resilient member with ends connected to the movable portion and the fixed portion;
• a coil, wherein only one lateral side of the movable portion is attached to the coil;
• and
• a flux providing unit providing a magnetic flux that generates respective driving forces on a plurality of driven coil portions positioned away from a center of gravity of the movable portion,
• the directions of the driving forces being non-parallel and crossing with each other such that respective torques generated on the movable portion by driving the driven coil portions counteract one another;
• wherein the plurality of driven coil portions are located on the same side of a plane passing through the center of gravity of the movable portion and extending, parallel to the one lateral side, in a direction in which the movable portion is driven;
• and
• wherein the flux providing unit includes:
• a first magnet having a first pole and a second pole with different polarities, the first magnet facing the coil;
• and
• a yoke disposed adjacent to the first magnet, the yoke including:
• a first yoke portion in which a second pole thereof with a polarity opposite to the first pole of the first magnet is positioned close to the first pole of the first magnet opposing the coil;
• and a second yoke portion in which a first pole thereof with a polarity opposite to the second pole of the first magnet is positioned close to the second pole of the first magnet opposing the coil,
• wherein the first magnet has a first opposing surface facing the one lateral side of the movable portion and the yoke has a second opposing surface facing a side of the movable portion that is perpendicular to the one lateral side of the movable portion, and
• wherein the first magnet and the yoke are disposed with the first opposing surface and the second opposing surface being perpendicular to each other.