Voice coil motor

Patent metadata

Field	Value
Publication number	US-9766532-B2
Application number	US-201514827964-A
Country	US
Kind code	B2
Filing date	Aug 17, 2015
Priority date	Nov 16, 2011
Publication date	Sep 19, 2017
Grant date	Sep 19, 2017

Abstract

A VCM is disclosed, the motor including a stator including a first driving unit, a rotor arranged inside the stator, including a second driving unit responding to the first driving unit and mounted therein with a lens, a base fixing the stator, and an elastic member coupled to the rotor to float the rotor from the base in a case a driving signal for driving the first and second driving units is not applied to the first and second driving units.

First claim

What is claimed is:

1. A lens driving device comprising:
a base;
a bobbin movably disposed over the base;
a cover disposed over the bobbin;
a first driving unit disposed at the bobbin; and
a second driving unit facing the first driving unit and configured to move the first driving unit by electromagnetic interaction,
wherein the bobbin is distanced from the base at an initial position;
wherein the bobbin includes a first stopper configured to contact the cover in a first direction, and a second stopper configured to contact the base in a second direction; and
wherein, at the initial position, a first distance between the first stopper and the cover is different from a second distance between the second stopper and the base.

2. The lens driving device of claim 1 , wherein the first distance is shorter than the second distance.

3. The lens driving device of claim 1 , wherein the first distance is longer than the second distance.

4. The lens driving device of claim 1 , wherein the cover includes an upper plate having an opening, and a lateral plate extended from an edge of the upper plate toward the base, and
wherein the lateral plate is coupled to the base.

5. The lens driving device of claim 1 , wherein the lens driving device is configured to move less than the first distance in the first direction when a first driving signal is applied to the first driving unit or the second driving unit, and the lens driving device is configured to move less than the second distance in the second direction when a second driving signal is applied to the first driving unit or the second driving unit.

6. The lens driving device of claim 5 , wherein the first driving signal is a positive current and the second driving signal is a negative current.

7. The lens driving device of claim 1 , wherein the first driving unit includes a coil block, and the second driving unit includes a magnet.

8. The lens driving device of claim 1 , wherein the first driving unit includes a magnet, and the second driving unit includes a coil block.

9. The lens driving device of claim 1 , wherein the first distance between the first stopper and the cover is a maximum of a first stroke length of the bobbin in the first direction, and the second distance between the second stopper and the base is a maximum of a second stroke length of the bobbin in the second direction.

10. The lens driving device of claim 1 , wherein the bobbin includes a hole formed therethrough and has a screw thread on an inner surface thereof for fixing a lens.

11. The lens driving device of claim 1 , wherein a groove is concavely formed on an upper surface of the base, and a portion of the bobbin is partially disposed in the groove.

12. The lens driving device of claim 1 , wherein the second direction is a direction approaching the base, and the first direction is a direction distancing from the base.

13. The lens driving device of claim 1 , wherein the first distance is from two to three times longer than the second distance.

14. The lens driving device of claim 1 , further comprising at least any one of a first shock absorber disposed between the first stopper and the cover, and a second shock absorber disposed between the second stopper and the base.

15. A The lens driving device of claim 1 , wherein the initial position is a position when no current is applied to the first driving unit and the second driving unit.

16. The lens driving device of claim 1 , wherein the bobbin is in a stationary state at the initial position when no driving signal is applied to the first driving, unit and the second driving unit.

17. A camera module, comprising:
a base;
a bobbin movably disposed over the base;
a lens coupled to the bobbin;
a cover disposed over the bobbin;
a coil block disposed at the bobbin;
a magnet facing the coil block and configured to move the coil block by electromagnetic interaction,
an image sensor disposed below the base; and
a filter disposed over the image sensor;
wherein the lens is distanced from the base at an initial position,
wherein the bobbin includes a first stopper configured to contact the cover in a first direction, and a second stopper configured to contact the base in a second direction,
wherein the bobbin moves from the initial position to an infinite focus position in the second direction, and from the initial position to a close-up focus position in the first direction opposite to the second direction, and
wherein a second stroke length between the initial position and the infinite focus position is different from a first stroke length between the initial position and the close-up focus position.

18. A digital apparatus comprising the camera module of claim 17 .

19. The camera module of claim 17 , wherein the second stroke length is shorter than the first stroke length.

20. The camera module of claim 19 , wherein the lens moves bi-directionally by PWM control.

Assignees

• Lg Innotek Co Ltd

Inventors

• Park Sang Ok
• Lee Seong Min

Classifications

• G02B7/102

  controlled by a microcomputer (cameras with interchangeable lenses G03B17/14) · CPC title

• H02K37/12

  with stationary armatures and rotating magnets · CPC title

• G02B13/001

  Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras (G02B23/243 takes precedence) · CPC title

• G03B2205/0069

  using electromagnetic actuators, e.g. voice coils · CPC title

• H02K41/0356

  moving along a straight path · CPC title