OPTICAL ELEMENT DRIVING DEVICE AND IMAGING APPARATUS

• US 20090128928A1
• Filed: 11/12/2008
• Published: 05/21/2009
• Est. Priority Date: 11/16/2007
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Ito, Daisuke
• Granted Patent: US 7,715,124 B2
• Time in Patent Office: Days
• US Class Current: 359/814
• CPC Class Codes: G02B 7/023 permitting adjustment
• CPC Class Codes: G02B 7/102 controlled by a microcomputer cameras with interchangeable lenses G03B17/14
• CPC Class Codes: H02K 2201/18 Machines moving with multiple degrees of freedom
• CPC Class Codes: H02K 41/0356 moving along a straight path

Abstract

A lens driving device includes a lens, a moving member that supports the lens, a stationary member that movably supports the moving member, a pitch drive mechanism that drives the moving member in the pitch correction direction, and a yaw drive mechanism that drives in the yaw correction direction. The pitch drive mechanism has first and second magnets provided to the stationary member, and first and second coils provided to the moving member. The yaw drive mechanism has a third magnet provided to the stationary member, and a third coil provided to the moving member. The first and second coils are arranged on opposite sides of the lens when viewed in a third direction that is perpendicular to the pitch and yaw correction directions, and the third coil is arranged on the same side as the first coil with respect to the lens when viewed in the third direction.

Claims

1. An optical element driving device comprising:

at least one optical element;

a moving member configured to support the optical element;

a stationary member configured to support the moving member to be movable in a first direction and a second direction intersecting the first direction;

a first direction drive mechanism having first and second drive parts provided to the stationary member, and first and second driven parts provided to the moving member and movable upon receiving a drive force from the first and second drive parts, and the first direction drive mechanism configured to drive the moving member in the first direction; and

a second direction drive mechanism having a third drive part provided to the stationary member, and a third driven part provided to the moving member and movable upon receiving a drive force form the third drive part, and the second direction drive mechanism configured to drive the moving member in the second direction,

the first and second driven parts arranged on opposite sides of the optical element when viewed in a third direction perpendicular to the first and second directions, and

the third driven part arranged on the same side of the optical element as the first driven part when viewed in the third direction.

2. The optical element driving device according to claim 1,

wherein, near a center of gravity of a portion of the optical element driving device that moves including the moving member,

a first moment that acts on the first driven part upon receiving the drive force of the first drive part and a second moment that acts on the second driven part upon receiving the drive force of the second drive part both act to substantially cancel each other out.

3. The optical element driving device according to claim 2,

wherein the first moment and the second moment completely cancel each other out.

4. The optical element driving device according to claim 3,

wherein the drive force of the first drive part is smaller than the drive force of the second drive part.

5. The optical element driving device according to claim 4,

wherein the third driven part is disposed closer than the first driven part to a first imaginary line parallel to the second direction and passing through the center of gravity.

6. The optical element driving device according to claim 5,

wherein the first and second driven parts are provided on opposite sides of the first imaginary line when viewed in the third direction.

7. The optical element driving device according to claim 6,

wherein the third driven part is disposed to be aligned with the first driven part in the first direction.

8. The optical element driving device according to claim 7,

further comprising a first guide part disposed between the center of gravity and the first driven part in the second direction, and configured to guide the moving member in the first direction with respect to the stationary member.

9. The optical element driving device according to claim 8,

further comprising a first position sensor arranged on the same side of the optical element as the first driven part, and configured to detect the position of the moving member in the first direction with respect to the stationary member.

10. The optical element driving device according to claim 9,

wherein the center of gravity overlaps the optical element when viewed in the third direction.

11. The optical element driving device according to claim 10,

wherein the first and second direction drive mechanisms are electromagnetic linear actuators,

the first, second and third driven parts have first, second and third coils provided to the moving member, respectively, and

the first, second and third drive parts have first, second and third magnets provided to the stationary member to be capable of being disposed opposite to the first, second and third coils, respectively.

12. The optical element driving device according to claim 11,

wherein the first magnet and the third magnet are formed integrally,

the first magnet is magnetized to different magnetic poles at a first boundary parallel to the second direction, and

the third magnet is magnetized to different magnetic poles at a third boundary parallel to the first direction.

13. The optical element driving device according to claim 12,

wherein the second drive part further has a fourth magnet that is magnetized tow different magnetic poles at a fourth boundary parallel to the first direction, and that is provided on the other side of the optical element than the third magnet,

the second magnet and the fourth magnet are formed integrally, the second magnet is magnetized to different magnet poles at a second boundary parallel to the second direction and the fourth magnet is magnetized to different magnetic poles at a fourth boundary parallel to the first direction, and

the first magnet and the second magnet are provided arranged on opposite sides of the first imaginary line.

14. The optical element driving device according to claim 13,

wherein the second direction drive mechanism further has a fourth coil disposed opposite the fourth magnet.

15. The optical element driving device according to claim 14,

further comprising a second guide part configured to guide the moving member in the second direction with respect to the stationary member,

wherein the moving member has:

a first moving frame that is mounted on the stationary member and is guided in the first direction by the first guide part, and

a second moving frame having a support part supporting the optical element, the second moving frame is mounted on the first moving frame and is guided in the second direction by the second guide part, and

the second guide part is disposed on the first moving frame at a position that does not overlap the third drive part in the first direction.

16. The optical element driving device according to claim 1,

wherein the drive force of the first drive part is smaller than the drive force of the second drive part.

17. The optical element driving device according to claim 1,

wherein the third driven part is disposed closer than the first driven part to a first imaginary line parallel to the second direction and passing through the center of gravity.

18. The optical element driving device according to claim 1,

wherein the first and second driven parts are provided on opposite sides of the first imaginary line when viewed in the third direction.

19. The optical element driving device according to claim 1,

wherein the third driven part is disposed to be aligned with the first driven part in the first direction.

20. (canceled)

21. An imaging apparatus capable of photographing a subject, the imaging apparatus comprising:

an imaging element configured to convert an optical image of the subject into an image signal;

an imaging optical system including a lens disposed opposite to the imaging element and configured to emit an optical image of the subject to the imaging element;

an optical image driving device configured to drive either the lens or the imaging element; and

a main body configured to house the imaging element, the imaging optical system and the optical element driving device;

wherein the optical image driving device includes;

a moving member configured to support either the lens or the imaging element;

a stationary member configured to support the moving member to be movable in a first direction and a second direction intersecting the first direction;

a first direction drive mechanism having first and second drive parts provided to the stationary member, and first and second driven parts provided to the moving member and movable upon receiving a drive force from the first and second drive parts, and the first direction drive mechanism configured to drive the moving member in the first direction; and

a second direction drive mechanism having a third drive part provided to the stationary member, and a third driven part provided to the moving member and movable upon receiving a drive force form the third drive part, and the second direction drive mechanism configured to drive the moving member in the second direction,

the first and second driven parts arranged on opposite sides of the optical element when viewed in a third direction perpendicular to the first and second directions, and

the third driven part arranged on the same side of the optical element as the first driven part when viewed in the third direction.