Lens drive device and electromagnetic drive unit
AssigneeTDK Corporation
InventorShusuke Ichihashi
Life of this patent
Estimating the term…
Abstract
A lens drive device includes a movable portion, a fixed portion, and a nonmagnetic case. The movable portion includes a double-pole magnet having two pairs of magnetic poles, a first coil opposing to the double-pole magnet in a perpendicular direction to a light axis, and a lens holder being movable to the double-pole magnet in a direction of the light axis. The fixed portion includes a second coil arranged so as to oppose to the double-pole magnet in the direction of the light axis. The nonmagnetic case is attached to the fixed portion so as to cover the movable portion. The double-pole magnet includes a first section and a second section. L1/L2 is 0.9 to 1.1, where L1 and L2 are respectively a length of the first and second sections in the direction of the light axis.
Claims17
A lens drive device comprising:
- a movable portion including a double-pole magnet having two pairs of magnetic poles, a first coil opposing to the double-pole magnet in a perpendicular direction to a light axis, and a lens holder holding the first coil and a lens and being movable to the double-pole magnet in a direction of the light axis;
- a fixed portion including a second coil arranged so as to oppose to the double-pole magnet in the direction of the light axis;
- a support portion configured to support the movable portion so that the movable portion is movable relatively to the fixed portion in the perpendicular direction to the light axis;
- and
- a nonmagnetic case provided with a through hole where light enters into the lens and attached to the fixed portion so as to cover the movable portion,
- wherein the double-pole magnet includes a first section having a first magnetization direction and opposing to the first coil and a second section having a second magnetization direction different from the first magnetization direction and opposing to the second coil, and
- L1/L2 is 0.9 to 1.1, where L1 is a length of the first section in the direction of the light axis, and L2 is a length of the second section in the direction of the light axis.
Dependencies are inferred from the claim text.