Lens driving device and camera

• US 9,933,628 B2
• Filed: 02/14/2013
• Issued: 04/03/2018
• Est. Priority Date: 02/14/2012
• Status: Expired due to Fees

• Current Assignee: Mitsumi Electric Co., Ltd. (MinebeaMitsumi Inc.)
• Original Assignee: Mitsumi Electric Co., Ltd. (MinebeaMitsumi Inc.)
• Inventors: Ariji, Makoto
• Primary Examiner(s): Pham, Thomas K
• Assistant Examiner(s): Pasko, Nicholas R
• Application Number:
  US14/377,185
• Publication Number:
  US 20160025995A1
• Time in Patent Office: 1,874 Days
• Field of Search: 359694-706, 359811-830
• CPC Class Codes: G02B 13/001 Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras G02B23/243 takes precedence
• CPC Class Codes: G02B 27/646 compensating for small deviations, e.g. due to vibration or shake movement of one or more optical elements for control of motion blur in cameras, projectors or printers G03B2205/0007; image stabilisation in cameras peculiar to the presence or use of an electronic image sensor H04N23/68
• CPC Class Codes: G02B 7/023 permitting adjustment
• CPC Class Codes: G02B 7/08 adapted to co-operate with a remote control mechanism
• CPC Class Codes: G02B 7/09 adapted for automatic focusing or varying magnification
• CPC Class Codes: G03B 2205/0007 Movement of one or more optical elements for control of motion blur imaging systems in general using optical elements for stabilisation of the position of the image G02B27/64
• CPC Class Codes: G03B 2205/0069 using electromagnetic actuators, e.g. voice coils
• CPC Class Codes: G03B 3/10 Power-operated focusing
• CPC Class Codes: G03B 3/12 adapted for remote control
• CPC Class Codes: G03B 5/02 Lateral adjustment of lens
• CPC Class Codes: G03B 5/04 Vertical adjustment of lens; Rising fronts
• CPC Class Codes: H04N 23/57 Mechanical or electrical details of cameras or camera modules specially adapted for being embedded in other devices
• CPC Class Codes: H04N 23/687 by shifting the lens or sensor position

Abstract

A lens driving device includes: a lens holder; a first coil wound onto the lens holder around the optical axis direction; a plurality of magnets having a first surface and a second surface perpendicular to the first surface, the magnets being disposed in a state in which the first surface opposes a circumferential surface of the first coil; a magnet holder that fixes the magnets apart from each other; a yoke constituting, together with the magnets, a magnetic circuit having a magnetic flux that traverses the first coil; a second coil provided opposite the second surface of the magnets; and a base on which the second coil is disposed. An auto-focus lens driving part that includes the lens holder, the first coil, the magnets, the magnet holder, and the yoke is held on the base so as to allow relative displacement in a direction perpendicular to the optical axis.

Claims

1. A lens driving device, comprising:

a lens holder to which a lens barrel is mounted, the lens holder being movable in a direction of an optical axis;

a first coil for auto-focusing wound around the lens holder about the optical axis;

a plurality of magnets that each have a rectangular shape extending in a longitudinal direction and a short-side direction orthogonal to the longitudinal direction while being magnetized in the short-side direction, wherein each of the plurality of magnets has a first surface that extends in the longitudinal direction and magnetized to a south pole or a north pole and a second surface that is perpendicular to the first surface and the optical axis, the first surface of the plurality of magnets facing a circumferential face of the first coil;

a magnet holder that fixes the plurality of magnets apart from each other;

a yoke comprising, together with the plurality of magnets, a magnetic circuit that generates a magnetic flux that crosses the first coil;

a second coil for image stabilizing that comprises a plurality of image stabilizer coil portions, each provided such that a coil plane thereof faces the second surface of a corresponding one of the plurality of magnets and each having a shape extending in the longitudinal direction of the magnet, which is opposite thereto; and

a base on which the second coil is disposed,

wherein an auto-focusing lens driving portion that includes the lens holder, the first coil, the plurality of magnets, the magnet holder and the yoke is held so as to be relatively movable in first and second directions perpendicular to the optical axis with respect to the base,

a position detection arrangement that detects a position of the auto-focusing lens driving portion with respect to the base, comprising;

a plurality of Hall elements, each provided facing the second surface of a corresponding one of the plurality of magnets,

wherein the plurality of image stabilizer coil portions include specific image stabilizer coil portions disposed in the first and the second directions, each of the specific image stabilizer coil portions being divided into a plurality of coil parts disposed along the longitudinal direction of the magnet, which is opposite thereto, and

wherein each Hall element of the plurality of Hall elements is disposed on an imaginary line parallel to the optical axis and passing between two of the plurality of coil parts of each of the specific image stabilizer coil portions.

2. The lens driving device according to claim 1, wherein the magnet holder is a polygonal frame body.

3. The lens driving device according to claim 2, wherein the plurality of magnets are fixed to the magnet holder at positions such that adjacent magnets are in a perpendicular relationship with respect to each other.

4. The lens driving device according to claim 3, wherein a number of the magnets is four.

5. The lens driving device according to claim 1, wherein a number of the first yoke portions is four.

6. The lens driving device according to claim 1, wherein the yoke is fixed to the magnet holder.

7. The lens driving device according to claim 1, wherein:

the yoke comprises further a plurality of members; and

a predetermined part of the lens holder is located in a space between two of the plurality of members.

8. The lens driving device according to claim 1, wherein an image pickup device is mounted on the base.

9. A camera comprising the lens driving device according to claim 1 incorporated therein.

10. The lens driving device according to claim 1, wherein the yoke further comprises a plurality of first yoke portions disposed apart from each other, and a frame-shaped second yoke portion, one of the plurality of the first yoke portions extending from an inner edge of the second yoke portion so as to correspond to a separation part between adjacent magnets and being disposed so that the first coil is positioned between the one of the plurality of the first yoke portions and the adjacent magnets, the second yoke portion being disposed facing a third surface opposite to the second surface of the plurality of magnets, and

wherein the one of the plurality of the first yoke portion comprises a first wall surface that faces a separation part between the adjacent magnets, and second wall surfaces that face end portions of the adjacent magnets, respectively.