Lens Driving Device and Camera Module Comprising Same

Patent metadata

Field	Value
Publication number	US-2017017056-A1
Application number	US-201515123906-A
Country	US
Kind code	A1
Filing date	Feb 25, 2015
Priority date	Mar 5, 2014
Publication date	Jan 19, 2017
Grant date	—

Abstract

A lens driving device according to an embodiment comprises: a movable unit on which at least one lens is mounted; a first coil and a driving magnet which face and interact with each other such that the movable unit is moved in the optical axis direction of the lens; a position sensor for sensing the position of the movable unit in the optical axis direction or a driver comprising the position sensor; and a positively magnetized magnet arranged to face the position sensor or the driver, wherein the positively magnetized magnet comprises a first side surface, which faces the position sensor and has a first polarity, and a second side surface, which faces the position sensor, which is arranged to be spaced from the first side surface in a direction parallel with the optical axis direction or arranged to abut the first side surface, and which has a second polarity that is the opposite of the first polarity of the first side surface, and the length of the first side surface in the optical axis direction may be equal to or larger than the length of the second side surface in the optical axis direction.

First claim

1 . A lens driving device, comprising:
a bobbin, at least one lens being mounted to the bobbin and a coil unit being disposed around an outer peripheral surface of the bobbin; a housing member, driving magnets being mounted to positions corresponding to the coil unit in the housing member; upper and lower elastic members resiliently supporting movement of the bobbin in a direction parallel to an optical axis direction of the lens, the upper elastic member having one end coupled to a top surface of the bobbin and the lower elastic member having one end coupled to a bottom surface of the bobbin; and a sensing unit sensing movement of the bobbin in the direction parallel to the optical axis direction, wherein the sensing unit includes: a sensing magnet mounted to the outer peripheral surface of the bobbin; and a circuit board mounted to a side wall of the housing member, a position sensor being disposed on an inner side surface thereof facing the sensing magnet.

2 . The lens driving device according to claim 1 , wherein the bobbin includes a magnet-mounting portion protruding from the outer peripheral surface thereof so that the sensing magnet is mounted to the magnet-mounting portion.

3 . The lens driving device according to claim 2 , wherein the magnet-mounting portion is disposed at a position capable of avoiding interference with the coil unit.

4 . The lens driving device according to claim 2 , wherein the magnet-mounting portion is disposed above the coil unit.

5 . The lens driving device according to claim 1 , wherein the driving magnets are disposed on two opposing surfaces of the housing member so as to be parallel to each other, and
the sensing magnet and the driving magnets are disposed on different surfaces so as not to face each other.

6 . A lens driving device, comprising:
a housing member having a hollow column shape for supporting driving magnets; a bobbin, a coil being mounted to an outer peripheral surface of the bobbin so as to face the driving magnets, and being configured to be moved in a first direction parallel to an optical axis in the housing member by electromagnetic interaction between the driving magnets and the coil; and a sensing unit sensing a first displacement value of the bobbin in the first direction.

7 . The lens driving device according to claim 6 , wherein the sensing unit includes:
a sensing magnet provided at the bobbin in a mounting, inserting, seating, contacting, coupling, securing, provisional securing, supporting or disposing manner; and a displacement sensing part provided at the housing member, at a position corresponding to the sensing magnet, in a mounting, inserting, seating, contacting, coupling, securing, supporting or disposing manner.

8 . The lens driving device according to claim 7 , wherein first and second driving magnets are provided on two opposing side surfaces of the housing member in a mounting, inserting, seating, contacting, coupling, securing, supporting or disposing manner, and
wherein the displacement sensing part is provided on a side surface perpendicular to the two side surfaces of the housing member or on a surface other than the two side surfaces of the housing member in a mounting, inserting, seating, contacting, coupling, securing, supporting or disposing manner.

9 . The lens driving device according to claim 7 , wherein the bobbin includes an accommodation recess formed to a predetermined depth in an inward direction from the outer peripheral surface of the bobbin so as to accommodate the sensing magnet.

10 . The lens driving device according to claim 9 , wherein the accommodation recess further includes:
an inner surface supporting one surface of the sensing magnet; and an adhesion recess formed concave to a predetermined depth in the inward direction from the inner surface so that an adhesive is injected into the adhesion recess.

11 . The lens driving device according to claim 10 , wherein the accommodation recess further includes a first additional recess extending from the adhesion recess, and
wherein an overall length of the adhesion recess and the first additional recess is longer than a length of the sensing magnet in a vertical thickness direction of the bobbin.

12 . The lens driving device according to claim 10 , wherein the accommodation recess further includes:
an opening formed in one of a bottom surface and a top surface of the bobbin so as to communicate with the accommodation recess; and a second additional recess extending from the adhesion recess and formed to a predetermined depth in the inward direction of the bobbin from the opening.

13 . The lens driving device according to claim 9 , wherein the bobbin further includes:
an additional accommodation recess formed to a predetermined depth in the inward direction from the outer peripheral surface of the bobbin, opposite the outer peripheral surface having the accommodation recess formed therein, at a position symmetrical to the accommodation recess about a center of the bobbin; and a weight-balancing member accommodated in the additional accommodation recess and having the same weight as the sensing magnet.

14 . A lens driving device, comprising:
a movable unit, at least one lens being mounted to the movable unit; a first coil and driving magnets arranged to face each other so as to move the movable unit in an optical axis direction of the lens through interaction therebetween; a position sensor sensing a position of the movable unit in the optical axis direction or a driver including the position sensor; and a bipolar-magnetized magnet disposed to face the position sensor or the driver, wherein the bipolar-magnetized magnet includes: a first side surface facing the position sensor and having a first polarity; and a second side surface facing the position sensor, disposed to be spaced apart from or in contact with the first side surface in a direction parallel to the optical axis direction, and having a second polarity opposite the first side surface, and wherein a length of the first side surface in the optical axis direction is equal to or longer than a length of the second side surface in the optical axis direction.

15 . The lens driving device according to claim 14 , wherein the bipolar-magnetized magnet includes:
first and second sensing magnets arranged to be spaced apart from each other; and a non-magnetic partition wall disposed between the first and sensing magnets.

16 . The lens driving device according to claim 15 , wherein the first side surface is positioned above the second side surface, and in an initial state before the lens is moved in the optical axis direction, a height of a middle portion of the position sensor is located on an imaginary horizontal plane extending from a top of the first side surface in a magnetization direction.

17 . The lens driving device according to claim 16 , wherein, in the initial state before the lens is moved in the optical axis direction, the height of the middle portion of the position sensor is aligned with a first point on the first side surface in the magnetization direction.

18 . The lens driving device according to claim 17 , wherein, in the initial state before the lens is moved in the optical axis direction, the height of the middle portion of the position sensor is aligned with a second point in the magnetization direction, the second point being located above the first point.

19 . The lens driving device according to claim 18 , wherein a difference between the second point and th

Assignees

• Lg Innotek Co Ltd

Inventors

• Park Sang Ok
• Son Byung Wook
• Lee Seong Min
• Lee Jun Taek

Classifications

• H02K41/0356

  moving along a straight path · CPC title

• G03B2205/0069

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

• G03B3/10

  Power-operated focusing · CPC title

• G02B7/08 Primary

  adapted to co-operate with a remote control mechanism · CPC title