Lens driving device, camera module, and camera-equipped portable terminal

• US 10,401,589 B2
• Filed: 07/08/2015
• Issued: 09/03/2019
• Est. Priority Date: 07/11/2014
• Status: Active Grant

• Current Assignee: Mitsumi Electric Co., Ltd. (MinebeaMitsumi Inc.)
• Original Assignee: Mitsumi Electric Co., Ltd. (MinebeaMitsumi Inc.)
• Inventors: Murakami, Tomoyuki
• Primary Examiner(s): Nguyen, Thong Q
• Application Number:
  US15/325,275
• Publication Number:
  US 20170192195A1
• Time in Patent Office: 1,518 Days
• 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 7/005 Motorised alignment
• CPC Class Codes: G02B 7/026 using retaining rings or springs G02B7/027 takes precedence
• CPC Class Codes: G02B 7/04 with mechanism for focusing or varying magnification
• CPC Class Codes: G02B 7/08 adapted to co-operate with a remote control mechanism
• CPC Class Codes: G03B 2205/0015 by displacing one or more optical elements normal to the optical axis
• CPC Class Codes: G03B 2205/0069 using electromagnetic actuators, e.g. voice coils
• CPC Class Codes: G03B 2217/005 Blur detection
• CPC Class Codes: G03B 3/10 Power-operated focusing
• CPC Class Codes: G03B 30/00 Camera modules comprising integrated lens units and imaging units, specially adapted for being embedded in other devices, e.g. mobile phones or vehicles
• CPC Class Codes: G03B 5/00 Adjustment of optical system relative to image or object surface other than for focusing

Abstract

A lens driving device comprising: an autofocus driving unit in which an autofocus movable part is elastically supported by an autofocus fixed part due to an elastic support part; and an auxiliary magnet which, in a reference position of the autofocus movable part, has a movement direction action force of zero relative to the autofocus movable part and which generates the movement direction action force in the opposite direction to a restoring force of the elastic support part when the autofocus movable part has moved.

Claims

1. A lens driving device comprising:

an auto-focusing driving part, and

an auxiliary magnet,

the auto-focusing driving part including;

an auto-focusing coil part disposed at a periphery of a lens part;

an auto-focusing magnet part having a yoke part and disposed separately from the auto-focusing coil part in a radial direction; and

an elastic supporting part configured to elastically support an auto focus movable part including the auto-focusing coil part with respect to an auto focus fixing part including the auto-focusing magnet part;

the auto-focusing driving part being configured to perform automatic focusing by moving the auto focus movable part in a light axis direction with respect to the auto focus fixing part by utilizing a driving force of a voice coil motor composed of the auto-focusing coil part and the auto-focusing magnet part;

the auxiliary magnet being configured to have no acting force in a movement direction with respect to the auto focus movable part at a reference position of the auto focus movable part, and being configured to generate an acting force in a movement direction in a direction opposite to a direction of a restoration force of the elastic supporting part when the auto focus movable part is moved, wherein

the auto-focusing magnet part is composed of four permanent magnets which are disposed in a square frame shape, each of the permanent magnets including the yoke part at an end surface in a longitudinal direction and being configured to be magnetized in a short direction; and

the auxiliary magnet includes;

a first auxiliary magnet disposed separately from the auto-focusing magnet part in the light axis direction at a position corresponding to one diagonal part of the auto-focusing magnet part; and

a second auxiliary magnet having a configuration similar to that of the first auxiliary magnet and disposed at a position symmetrical with a position of the first auxiliary magnet about the light axis direction.

2. The lens driving device according to claim 1, wherein the yoke parts adjacent to each other are coupled with each other.

3. The lens driving device according to claim 1, wherein the auto focus movable part includes a lens holder, the lens holder includes:

a coil winding part for disposing the auto-focusing coil part;

a tying part for tying both ends of the auto-focusing coil part; and

wherein the tying part is formed to protrude outward in a radial direction and has a tapered shape whose diameter is reduced toward an inner side in the radial direction.

4. The lens driving device according to claim 1 further comprising a shake-correcting driving part, the shake-correcting driving part including:

a shake-correcting magnet part disposed at an auto focus unit including the auto focus movable part and the auto focus fixing part; and

a shake-correcting coil part disposed separately from the shake-correcting magnet part in the light axis direction;

the shake-correcting driving part being configured to perform shake correction by swinging a shake-correcting movable part including the shake-correcting magnet part in a plane orthogonal to the light axis direction with respect to a shake-correcting fixing part including the shake-correcting coil part by utilizing a driving force of a voice coil motor composed of the shake-correcting coil part and the shake-correcting magnet part.

5. The lens driving device according to claim 4, wherein the auto-focusing magnet part serves also as the shake-correcting magnet.

6. A camera module comprising:

the lens driving device according to claim 1;

a lens part mounted to the auto focus movable part; and

an image capturing part configured to capture a subject image imaged by the lens part.

7. A camera-equipped mobile terminal comprising the camera module according to claim 6.