JP2004048873A5

JP2004048873A5 -

Info

Publication number: JP2004048873A5
Application number: JP2002200992A
Authority: JP
Filing date: 2002-07-10
Publication date: 2005-10-20
Anticipated expiration: 2022-07-10

Claims

A rotatable hollow cylindrical magnet whose outer peripheral surface is divided in the circumferential direction and alternately magnetized to different poles, a coil disposed in the direction of the rotation axis of the magnet , a tooth-shaped outer magnetic pole portion and an inner magnetic pole The optical axis is linked to the rotation of the magnet, with a portion facing the outer peripheral surface and the inner peripheral surface of the magnet, a stator excited by the coil, and a lens having an opening on the inner diameter side of the inner magnetic pole portion as an optical path. A lens driving device having a lens positioning mechanism for moving the lens in the direction to change the position of the lens in the optical axis direction,
A first position where a rotational position of the magnet is held by an attractive force between the magnet and the outer magnetic pole when no power is supplied to the coil; and a position where the magnet is rotated by a predetermined angle from the first position. And having a regulating member for regulating a second position where the rotational position of the magnet is held by the attractive force between the magnet and the outer magnetic pole portion when the coil is not energized. A lens driving device that switches between a position of 1 and the second position .

The outer magnetic pole portion is opposed to the outer peripheral surface of the magnet at a predetermined angle, and a ratio of the predetermined angle of the outer magnetic pole portion facing the magnet to an angle per one pole of the magnet is set. Y, where X is the ratio of the circumferential length per pole of the magnet to the radial thickness of the magnet
-0.3X + 0.63> Y
The lens driving device according to claim 1, wherein the following condition is satisfied .

The restricting member restricts the rotation range of the magnet so that it can rotate from one to the other between the first position and the second position, and the magnet is moved to the first position or the first position. In the state of reaching the position 2, the center of one pole of the magnet forms a certain angle with respect to the center of each magnetic pole part, and when the coil is de-energized in this state, Restricting the relationship of the magnet with respect to the outer magnetic pole part so that a magnetic force that opposes the center of one pole of the magnet to the center acts as a force for maintaining the state of the first position or the second position;
The lens positioning mechanism moves the lens in the first lens position or the second lens position in conjunction with rotation of the magnet from one to the other between the first position and the second position. The lens driving device according to claim 1 , wherein the lens driving device is changed to any one of the above.

The lens positioning mechanism comprises a male helicoid part and a female helicoid part coupled to the male helicoid part,
One of the male helicoid part and the female helicoid part is formed on a cylindrical holding member that holds the lens, and the other is formed on a member that is fixed to the inner wall surface of the inner magnetic pole part .
2. The lens according to claim 1, wherein the lens moves in the optical axis direction by the action of the male helicoid part and the female helicoid part as the holding member rotates in conjunction with rotation of the magnet. 3. Drive device.

The lens positioning mechanism comprises a male helicoid part and a female helicoid part coupled to the male helicoid part,
One of the male helicoid part and the female helicoid part is formed on a cylindrical holding member that holds the lens, and the other is an inner wall surface of a fixing member that is concentric with the stator and arranged in an axial direction. Formed into
2. The lens drive according to claim 1, wherein the lens is moved in the optical axis direction by the action of the male helicoid part and the female helicoid part as the holding member rotates in accordance with the rotation of the magnet. apparatus.