Lens driving device and camera module comprising same

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.

The invention claimed is: 
     
       1. A lens driving device, comprising:
 a cover member comprising: a first lateral plate, a second lateral plate disposed opposite to the first lateral plate, a third lateral plate, and a fourth lateral plate disposed opposite to the third lateral plate; 
 a first lateral plate: 
 a second lateral plate disposed opposite to the first lateral plate; 
 a third lateral plate; and 
 a fourth lateral plate disposed opposite to the third lateral plate; 
 a bobbin disposed in the cover member; 
 a housing member disposed in between the cover member and the bobbin; 
 a bobbin disposed in the housing member; 
 a coil unit disposed around an outer peripheral surface of the bobbin; 
 first and second driving magnets facing the coilunit, wherein the first and second driving magnets are coupled to the first lateral plate and the second lateral plate of the cover member, respectively; 
 an upper elastic member coupled to an upper surface of the bobbin; 
 a lower elastic member coupled to a lower surface of the bobbin; 
 a sensing magnet disposed on a side wall of the bobbin, overlapped with the third lateral plate of the cover member; and 
 a position sensor facing disposed opposite to the sensing magnet and being configured to sense a movement of the sensing magnet in a z-direction first direction along an optical axis, 
 wherein the side wall of the bobbin is overlapped with the third lateral plate of the cover member in an x-axis direction perpendicular to the z-axis direction and perpendicular to the fourth lateral plate, and 
 wherein the sensing magnet is not overlapped with the coil unit and the third lateral plate of the cover member in the x-axis direction 
 wherein the sensing magnet is disposed on a first surface of the bobbin corresponding with the third lateral plate of the cover member, and 
 wherein the sensing magnet is overlapped with the coil in the first direction. 
 
     
     
       2. The lens driving device according to  claim 1 , wherein the bobbin comprises a recess formed on the side wall first surface of the bobbin, and
 wherein the sensing magnet is disposed in on the recess of the bobbin. 
 
     
     
       3. The lens driving device according to  claim 1 , wherein the lower elastic member comprises a first lower elastic member and a second lower elastic member spaced apart from the first lower elastic member, and
 wherein the first and second lower elastic members are connected to two ends of the coil unit, respectively. 
 
     
     
       4. The lens driving device according to  claim 1 , wherein the sensing magnet is disposed above the coil unit in the z-axis first direction. 
     
     
       5. The lens driving device according to  claim 1 , wherein
 at least a portion of the sensing magnet is disposed more inwardly toward the optical axis than is the coilunit as measured from the outer peripheral surface of the bobbin. 
 
     
     
       6. The lens driving device according to  claim 1 , wherein the sensing magnet comprises a bipolar-magnetized magnet:
 a first portion facing the position sensor and having a first polarity; and 
 a second portion facing the position sensor, disposed to be spaced apart from or in contact with the first portion in the first direction, and having a second polarity opposite the first polarity. 
 
     
     
       7. The lens driving device according to  claim 1 , wherein an opening is formed at the third lateral plate of the cover member, and
 wherein the sensing magnet is overlapped with the opening in the x-axis a second direction perpendicular to the first direction and perpendicular to the fourth lateral plate. 
 
     
     
       8. The lens driving device according to  claim 7 , wherein the opening is a hole. 
     
     
       9. The lens driving device according to  claim 1 , further comprising:
 a circuit board coupled with the position sensor; and 
 a base coupled with the cover member, 
 wherein the circuit board comprises a plurality of terminals, 
 wherein the first and second driving magnets are disposed on the housing member in a y-axis direction perpendicular to each of the z-axis and x-axis directions, so as to be in parallel to each other, and 
 wherein the circuit board is disposed at a position corresponding to a position of a side wall of at least one of the bobbin, the housing member, and the cover member in the x-axis direction, and 
 wherein the lower elastic member is electrically connected to the circuit board. 
 
     
     
       10. The lens driving device according to  claim 2 , wherein the bobbin further comprises an additional recess disposed opposite to the recess; and
 wherein a weight-balancing member is disposed in on the additional recess and has a weight same as that of the sensing magnet. 
 
     
     
       11. The lens driving device according to  claim 6 , wherein the bipolar-magnetized magnet comprises:
 a first portion facing the position sensor and having a first polarity; and 
 a second portion facing the position sensor, disposed to be spaced apart from or in contact with the first portion in the z-axis direction, and having a second polarity opposite the first polarity, and 
 wherein a length of the first portion of the sensing magnet in the z-axis first direction is equal to or greater than a length of the second portion of the sensing magnet in the z-axis first direction. 
 
     
     
       12. The lens driving device according to  claim 1 , wherein the first and second driving magnets are bonded and fixed to the first and second lateral plates of the cover member, respectively, and
 wherein a size of the sensing magnet is smaller than that of each of the first and second driving magnets. 
 
     
     
       13. The lens driving device according to  claim 1 , further comprising an inner yoke integrally formed with the cover member,
 wherein the inner yoke is disposed at a position corresponding to that of a corner of the housing member, and 
 wherein the inner yoke comprises: comprises a bent portion bent downwardly from the cover member, and a bottleneck section formed at positions adjacent to the bent portion 
 a bent portion bent downwardly from the cover member; and 
 a bottleneck section formed at positions adjacent to the bent portion, the bottleneck section of the inner yoke being symmetrically formed. 
 
     
     
       14. The lens driving device according to  claim 3 , wherein the two ends of the coil unit are arranged disposed on opposite sides with respect to the optical axis. 
     
     
       15. The lens driving device according to  claim 1 , wherein the bobbin comprises a plurality of lower support protrusions protruded protruding from the lower surface thereof,
 wherein the lower elastic member comprises a plurality of through holes formed at positions corresponding to positions of the lower support protrusions, and 
 wherein the lower support protrusions are secured to the through holes and are arranged disposed in a symmetrical manner with respect to the optical axis. 
 
     
     
       16. A camera module, comprising:
 a cover member comprising a first lateral plate, a second lateral plate disposed opposite to the first lateral plate, a third lateral plate, and a fourth lateral plate disposed opposite to the third lateral plate;   a housing member disposed in the cover member;   a bobbin disposed in the housing member;   a lens coupled to the bobbin;   a coil unit disposed around an outer peripheral surface of the bobbin;   first and second driving magnets facing the coil unit, wherein the first and second driving magnets are coupled to the first lateral plate and the second lateral plate of the cover member, respectively;   an upper elastic member coupled to an upper surface of the bobbin;   a lower elastic member coupled to a lower surface of the bobbin;   a sensing magnet disposed on a side wall of the bobbin and overlapped with the third lateral plate of the cover member;   a position sensor facing the sensing magnet and being configured to sense a movement of the sensing magnet in a z-axis direction along an optical axis,   a first circuit board; and   an image sensor coupled to the first circuit board,   wherein the side wall of the bobbin is overlapped with the third lateral plate of the cover member in an x-axis direction perpendicular to the z-axis direction and perpendicular to the fourth lateral plate, and   wherein the sensing magnet is not overlapped with the coil unit and the third lateral plate of the cover member in the x-axis direction.   
     
     
       17. The camera module according to  claim 16 , wherein an opening is formed at the third lateral plate of the cover member, and
 wherein the sensing magnet is overlapped with the opening in the x-axis direction.   
     
     
       18. The camera module according to  claim 17 , wherein the opening is a hole. 
     
     
       19. The camera module according to  claim 16 , further comprising:
 a second circuit board coupled with the position sensor; and   a base coupled with the cover member,   wherein the second circuit board comprises a plurality of terminals, and   wherein the lower elastic member is connected to the second circuit board.   
     
     
       20. A lens driving device, comprising:
 a cover member comprising a first lateral plate, a second lateral plate disposed opposite to the first lateral plate, a third lateral plate, and a fourth lateral plate disposed opposite to the third lateral plate; 
 a housing member disposed in the cover member; 
 a bobbin disposed in the housing member; 
 a coil unit disposed around wound on an outer peripheral surface of the bobbin; 
 first and second driving magnets facing the coil unit, wherein the first and second driving magnets are coupled to the first lateral plate and the second lateral plate of the cover member, respectively; 
 a sensing magnet disposed on a side wall of the bobbinand overlapped with the third lateral plate of the cover member; 
 a position sensor facing disposed opposite to the sensing magnet and being configured to sense a movement of the sensing magnet in a z-axis direction along an optical axis, and 
 an opening formed at the third lateral plate of the cover member, 
 wherein the side wall of the bobbin is overlapped with the third lateral plate of the cover member in an x-axis direction perpendicular to the z-axis direction and perpendicular to the fourth lateral plate, and 
 wherein the sensing magnet is not overlapped with the coil unit and is overlapped with the opening in the x-axis direction, and 
 wherein the sensing magnet is overlapped with the coil in the z-axis direction. 
 
     
     
       21. The lens driving device according to claim 20, wherein the bobbin comprises a recess formed on the side wall of the bobbin, and
 wherein the sensing magnet is disposed on the recess of the bobbin.   
     
     
       22. The lens driving device according to claim 21, wherein the lower elastic member comprises a first lower elastic member and a second lower elastic member spaced apart from the first lower elastic member, and
 wherein the first and second lower elastic members are connected to two ends of the coil, respectively.   
     
     
       23. The lens driving device according to claim 22, comprising:
 a circuit board coupled with the position sensor; and   a base coupled with the cover member,   wherein the circuit board comprises a plurality of terminals,   wherein the first and second driving magnets are disposed on the housing member so as to be in parallel to each other, and   wherein the lower elastic member is electrically connected to the circuit board.   
     
     
       24. A camera module, comprising:
 a printed circuit board;   an image sensor disposed on the printed circuit board;   the lens driving device of claim 20; and   a lens coupled to the bobbin of the lens driving device and spaced apart from the image sensor.   
     
     
       25. A lens driving device, comprising:
 a cover member comprising a first lateral plate, a second lateral plate disposed opposite to the first lateral plate, a third lateral plate, and a fourth lateral plate disposed opposite to the third lateral plate;   a bobbin disposed in the cover member;   a housing member disposed between the cover member and the bobbin;   a coil wound on an outer peripheral surface of the bobbin;   first and second driving magnets facing the coil, wherein the first and second driving magnets are coupled to the first lateral plate and the second lateral plate of the cover member, respectively;   an upper elastic member coupled to an upper surface of the bobbin;   a lower elastic member coupled to a lower surface of the bobbin;   a sensing magnet disposed on the bobbin; and   a position sensor disposed opposite to the sensing magnet and being configured to sense a movement of the sensing magnet in a direction along an optical axis,   wherein the sensing magnet is disposed on a first surface of the bobbin corresponding with the third lateral plate of the cover member, and   wherein the third lateral plate of the cover member comprises an opening formed at a position corresponding to the sensing magnet.   
     
     
       26. The lens driving device according to claim 25, wherein the bobbin comprises a recess formed on the first surface of the bobbin, and
 wherein the sensing magnet is disposed on the recess of the bobbin.   
     
     
       27. The lens driving device according to claim 26, wherein the lower elastic member comprises a first lower elastic member and a second lower elastic member spaced apart from the first lower elastic member, and
 wherein the first and second lower elastic members are connected to two ends of the coil, respectively.   
     
     
       28. The lens driving device according to claim 27, comprising:
 a circuit board coupled with the position sensor; and   a base coupled with the cover member,   wherein the circuit board comprises a plurality of terminals,   wherein the first and second driving magnets are disposed on the housing member so as to be in parallel to each other, and   wherein the lower elastic member is electrically connected to the circuit board.   
     
     
       29. A camera module, comprising:
 a printed circuit board;   an image sensor disposed on the printed circuit board;   the lens driving device of claim 25; and   a lens coupled to the bobbin of the lens driving device and spaced apart from the image sensor.   
     
     
       30. The lens driving device according to claim 1, wherein the coil surrounds the outer peripheral surface of the bobbin, and
 wherein the sensing magnet is not overlapped with the coil and the third lateral plate of the cover member in a second direction perpendicular to the first direction and perpendicular to the fourth latera plate.   
     
     
       31. The lens driving device according to claim 1, wherein the sensing magnet is fixed to the bobbin by an adhesive and does not protrude outside the bobbin. 
     
     
       32. A camera module, comprising:
 a printed circuit board;   an image sensor disposed on the printed circuit board;   the lens driving device of claim 1; and   a lens coupled to the bobbin of the lens driving device and spaced apart from the image sensor.   
     
     
       33. A mobile phone comprising the camera module of claim 32.