Abstract:
An actuator includes a stationary member defining a first receiving room and a center axis, a moveable member received in the first receiving room and being apart from the stationary member, a driving member, and a resilient spring assembly. The moveable member is coaxial with the stationary member. The driving member comprises a first magnetic assembly fixed to the stationary member and a second magnetic assembly fixed to the moveable member. The first magnetic assembly faces the second magnetic assembly. The driving member is configured for driving the moveable member to move along a first axis and a second axis perpendicular to the first axis. The first axis and the second axis are perpendicular to the central axis. The spring assembly is positioned between the stationary member and the moveable member and connects the moveable member to the stationary member. The spring assembly elastically deforms when the moveable member moves.

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure relates to imaging technologies and, particularly, to an actuator and an anti-vibration camera module having such actuator. 
     2. Description of Related Art 
     With ongoing developments in imaging and multimedia technology, camera modules have become widely used in many kinds of consumer electronic devices, such as cellular phones, laptops, digital cameras, personal digital assistants (PDAs), etc. Generally, a camera module includes a lens module, an image sensor such as a charge-coupled device (CCD) or a complementary metal oxide semiconductor (COMS). Light reflected by an object passes through the lens module to impinge on the image sensor. The image sensor is configured for capturing an image of the object by receiving the light. 
     However, image quality of these electronic devices is negatively affected when subjected to vibration from external forces. Such vibration causes deflection of the optical axis of the camera module, resulting in a blurred image being captured. 
     Therefore, what is needed is an actuator and an anti-vibration camera module using the same which can overcome the above-mentioned problems. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Many aspects of the present actuator and the present anti-vibration camera module can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, the emphasis instead being placed upon clearly illustrating the principles of the actuator and the anti-vibration camera module. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
         FIG. 1  is a schematic, isometric view of an actuator including a moveable member and a resilient spring assembly, according to a first exemplary embodiment. 
         FIG. 2  is an exploded view of the actuator of  FIG. 1 . 
         FIG. 3  is an enlarged view of the moveable member and the spring assembly of  FIG. 2 . 
         FIG. 4  is a schematic view of a working principle of the actuator of  FIG. 1 , showing movement of the moveable member along an X axis. 
         FIG. 5  is similar to  FIG. 4 , but showing movement of the moveable member along a Y axis. 
         FIG. 6  is an exploded view of an actuator, according to a second exemplary embodiment. 
         FIG. 7  is a schematic view of a working principle of the actuator of  FIG. 6 , showing movement of a moveable member along an X axis. 
         FIG. 8  is a sectional view of an anti-vibration camera module, according to a third exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1 and 2 , an actuator  100 , according to a first exemplary embodiment, includes a stationary member  10 , a moveable member  20 , a driving member  30 , and a resilient spring assembly  40 . 
     The stationary member  10  is an approximately cuboid frame and includes an upper frame  11 , a lower frame  12 , a first post  14 , a second post  16 , a third post  17 , and a fourth post  18 . The upper frame  11  and the lower frame  12  are positioned at opposite sides of the stationary member  10 . The four posts  14 ,  16 ,  17  and  18  connect the upper frame  11  to the lower frame  12  at respective four corners of the upper frame  11  and the lower frame  12 . 
     A central axis (Z axis) and a first receiving room  19  are defined in the stationary member  10 . A first receiving hole  102 , a second receiving hole  104 , a third receiving hole  106 , and a fourth receiving hole  108  are respectively defined in four sides of the stationary member  10 . The first receiving hole  102  and the third receiving hole  106  are at opposite sides of the stationary member  10 . The second receiving hole  104  and the fourth receiving hole  108  are at the other opposite sides of the stationary member  10 . The four receiving holes  102 ,  104 ,  106  and  108  are in communication with the first receiving room  19 . 
     A first protrusion  142  is formed on a side of the first post  14  in the fourth receiving hole  108 . A second protrusion  172  is formed on a side of the third post  17  in the second receiving hole  104 . In this embodiment, the two protrusions  142  and  172  are nearer to the upper frame  11  than to the lower frame  12 . The two protrusions  142  and  172  are cylinder. 
     Referring to  FIG. 3  together with  FIG. 2 , the moveable member  20  is an approximately cuboid frame and received in the first receiving room  19 . The moveable member  20  includes a first frame  21 , a second frame  22 , a first pole  24 , a second pole  26 , a third pole  27  and a fourth pole  28 . The first frame  21  and the second frame  22  are positioned at opposite sides of the moveable member  20 . The four poles  24 ,  26 ,  27  and  28  connect the first frame  21  to the second frame  22  at the respective four corners of the first frame  21  and the second frame  22 . 
     A second receiving hole  29  is defined in the moveable member  20  and configured for receiving an image sensor (not shown) or a lens module (not shown) or both the image sensor and the lens module. A first receiving groove  202 , a second receiving groove  204 , a third receiving groove  206  and a fourth receiving groove  208  are respectively defined on the four sides of the moveable member  20 . The four receiving grooves  202 ,  204 ,  206  and  208  align with the four receiving holes  102 ,  104 ,  106  and  108 , respectively. 
     The driving member  30  is configured for driving the moveable member  20  to move along an X axis or a Y axis perpendicular to the X axis. The X axis and the Y axis are perpendicular to the Z axis. The driving member  30  includes a first magnetic assembly  32  and a second magnetic assembly  34 . The first magnetic assembly  32  is fixed to the stationary member  10 . The second magnetic assembly  34  is fixed to the moveable member  20  facing the first magnetic assembly  32 . 
     The first magnetic assembly  32  includes a first coil  322 , a second coil  324 , a third coil  326  and a fourth coil  328 . The four coils  322 ,  324 ,  326  and  328  are rectangular. The first coil  322  is received in the first receiving hole  102  and includes a first upper side  3222  and a first lower side  3224  opposite to the first upper side  3222 . The second coil  324  is received in the second receiving hole  104  and includes a second upper side  3242  and a second lower side  3242  opposite to the second upper side  3242 . The third coil  326  is received in the third receiving hole  106  and includes a third upper side  3262  and a third lower side  3264  opposite to the third upper side  3262 . The fourth coil  328  is received in the fourth receiving hole  108  and includes a fourth upper side  3282  and a fourth lower side  3284  opposite to the fourth upper side  3282 . An electric current can be applied to the four coils  322 ,  324 ,  326  and  328 . 
     The second magnetic assembly  34  includes a first magnet unit  342 , a second magnet unit  344 , a third magnet unit  346 , and a fourth magnet  348 . 
     The first magnet unit  342  is received in the first receiving groove  202  to face the first coil  322 . The first magnet unit  342  includes a first upper magnet  3422 , a first middle magnet  3424 , and a first lower magnet  3426 . The three magnets  3422 ,  3424  and  3426  are adhesively attached to each other. The magnetic north of the first upper magnet  3422  faces the first coil  322 . The magnetic south of the first middle magnet  3424  faces the first coil  322 . The magnetic north of the first lower magnet  3426  faces the first coil  322 . 
     The second magnet unit  344  is received in the second receiving groove  204  to face the second coil  324 . The second magnet unit  344  includes a second upper magnet  3442 , a second middle magnet  3444 , and a second lower magnet  3446 . The three magnets  3442 ,  3444  and  3446  are adhesively attached to each other. The third magnet unit  346  is received in the third receiving groove  206  to face the third coil  326 . The third magnet unit  346  includes a third upper magnet  3462 , a third middle magnet  3464 , and a third lower magnet  3466 . The three magnets  3462 ,  3464  and  3466  are adhesively attached to each other. The fourth magnet unit  348  is received in the fourth receiving groove  208  to face the fourth coil  328 . The fourth magnet unit  348  includes a fourth upper magnet  3482 , a fourth middle magnet  3484 , and a fourth lower magnet  3486 . The fourth magnets  3482 ,  3484 , and  3486  are adhesively attached to each other. The magnetic pole distribution of the second magnet unit  344 , the third magnet unit  346 , and the fourth magnet unit  348  are the same as the first magnet unit  342 . 
     The spring assembly  40  is positioned between the stationary member  10  and the moveable member  20 . The spring assembly  40  includes a first elastic member  42  and a second elastic member  44 . 
     The first elastic member  42  includes a first arm  422  and a second arm  424  connected to the first arm  422 . An included angle between the first arm  422  and the second arm  424  is an obtuse angle. A first through hole  4224  is defined in a distal end  4222  of the first elastic member  42  for fixedly receiving the first protrusion  142 . 
     The second elastic member  44  includes a third arm  442  and a fourth arm  444  connected to the third arm  442 . An included angle between the third arm  442  and the fourth arm  444  is an obtuse angle. A second through hole  4444  is defined in a distal end  4442  of the second elastic member  44  for fixedly receiving the second protrusion  172 . 
     The first protrusion  142  extends through the first through hole  4224 . The distal end  4222  of the first elastic member  42  is fixed to the first post  14  and a distal end  4226  of the first elastic member  42  is fixed to the third pole  27 . The second protrusion  172  extends through the second through hole  4444 . The distal end  4442  of the second elastic member  44  is fixed to the third post  17  and a distal end  4446  of the second elastic member  44  is fixed to the first pole  24 . Thereby, the spring assembly  40  connects the moveable member  20  to the stationary member  10 . 
     Referring to  FIG. 4  and together with  FIG. 2 , when in use, an electrical current is applied to the first coil  322  and the third coil  326 . Directions of the electric current of the first coil  322  and the third coil  326  are counterclockwise shown as an arrow, viewing from an X axis. The first upper side  3222  and the first lower side  3224  produce magnetic fields. According to Ampere&#39;s rule, viewing from Y axis, the direction of a magnetic induction line generated by the first upper side  3222  is clockwise, and a direction of the magnetic induction line generated by the first lower side  3224  is counterclockwise. The direction of the magnetic induction line between the first upper magnet  3422  and the first middle magnet  3424  is counterclockwise, and the direction of the magnetic induction line between the first middle magnet  3424  and the first lower magnet  3426  is clockwise. Therefore, a repulsion force F 1  is produced between the first coil  322  and the first magnetic unit  342 . According to the same principle as detailed above, an attractive force F 2  is produced between the third coil  326  and the third magnetic unit  346 . As a result, the moveable member  20  has a movement along the negative direction of the X axis. 
     Referring to  FIG. 5  and together with  FIG. 2 , an electrical current is applied to the second coil  324  and the fourth coil  328 . Direction of the electric current of the second coil  324  and the fourth coil  328  are clockwise shown as an arrow, viewing from a Y axis. According to the same principle as detailed above, viewing from X axis, a repulsion force F 3  is produced between the fourth coil  328  and the fourth magnetic unit  348 . An attractive force F 4  is produced between the second coil  324  and the second magnetic unit  344 . As a result, the moveable member  20  has a movement along the positive direction of the Y axis. Therefore, the driving member  30  moves the lens module or image sensor received in the moveable member  20  along the X axis or the Y axis to compensate for vibration. At the same time, the spring assembly  40  is deformable by a force between the moveable member  20  and the stationary member  10 . After compensating for vibration, the current applied to the four coils  322 ,  324 ,  326  and  328  is canceled, the moveable member  20  is drawn back to align with the stationary member  10  by the spring assembly  40 . 
     It is to be understand that electrical current can be applied to the four coils  322 ,  324 ,  326  and  328  at the same time, the moveable member  20  then moves along the X axis and the Y axis simultaneously. 
     Referring to  FIG. 6 , an actuator  500 , according to a second exemplary embodiment is shown. The difference between the actuator  500  of this embodiment and the actuator  100  of the first embodiment are that: the first magnetic assembly  62  includes a first coil unit  622 , a second coil unit  624 , a third coil unit  626  and a fourth coil unit  628 . The first coil unit  622  includes a first upper coil  6222  and a first lower coil  6224 . The lower side  6223  of the first upper coil  6222  is positioned on the upper side  6225  of the first lower coil  6224 . The second coil unit  624  includes a second upper coil  6242  and a second lower coil  6244 . The lower side  6243  of the second upper coil  6242  is positioned on the upper side  6245  of the second lower coil  6244 . The third coil unit  626  includes a third upper coil  6262  and a third lower coil  6264 . The lower side  6263  of the third upper coil  6262  is positioned on the upper side  6265  of the third lower coil  6264 . The fourth coil unit  628  includes a fourth upper coil  6282  and a fourth lower coil  6284 . The lower side  6283  of the fourth upper coil  6282  is positioned on the upper side  6285  of the fourth lower coil  6284 . 
     The second magnetic assembly  64  includes a first magnet unit  642 , a second magnet unit  644 , a third magnet unit  646  and a fourth magnet unit  648 . The first magnet unit  642  includes a first upper magnet  6422 , a first middle magnet  6424 , a first sub-magnet  6426  and a first lower magnet  6428 . The four magnets  6422 ,  6424 ,  6426 , and  6428  are adhesively attached to each other. The magnetic south of the first upper magnet  6422  faces the first coil unit  622 . The magnetic north of the first middle magnet  6424  faces the first coil unit  622 . The magnetic south of the first sub-magnet  6426  faces the first coil unit  622 . The magnetic north of the first lower magnet  6428  faces the first coil unit  622 . The structure and the magnetic pole distribution of the second magnet unit  644 , the third magnet unit  646 , and the fourth magnet unit  648  are the same as the first magnet unit  642 . 
     Referring to  FIG. 7  together with  FIG. 6 , when in use, an electrical current is applied to the first coil unit  622  and the third coil unit  626  shown as arrow. The first coil unit  622  and the third coil unit  626  produce magnetic fields. According to Ampere&#39;s rule, viewing from the Y axis, the direction of the magnetic induction line generated by the upper side  6221  of the first upper coil  6222  is clockwise. The directions of the magnetic induction line generated by the lower side  6223  of the first upper coil  6222  and the upper side  6225  of the first lower coil  6224  are counterclockwise, and the direction of the magnetic induction line generated by the lower side  6227  of the first lower coil  6227  is clockwise. The direction of the magnetic induction line between the first upper magnet  6422  and the first middle magnet  6424  is clockwise. The direction of the magnetic induction line between the first sub-magnet  6426  and the first middle magnet  6424  is counterclockwise, and the direction of the magnetic induction line between the first sub-magnet  6426  and the first lower magnet  6428  is clockwise. Therefore, an attractive force F 5  is produced between the first coil unit  622  and the first magnetic unit  642 . According to the same principle as detailed above, a repulsion force F 6  is produced between the third coil unit  626  and the third magnetic unit  646 . As a result, the moveable member  20  has movement along the positive direction of X axis. 
     According to the same principle as detailed above, an attractive force is produced between the fourth coil unit  628  and the fourth magnetic unit  648 . A repulsion force is produced between the second coil unit  624  and the second magnetic unit  644 . As a result, the moveable member  20  has movement along the negative direction of Y axis. 
     Advantages of the actuator  500  of the second embodiment are similar to those of the actuator  100  of the first embodiment. Further, if the same electrical current is applied to the actuator  500  and the actuator  100 , the driving force applied to the actuator  500  is bigger than that of the actuator  100 . 
     Referring to  FIG. 8 , an anti-vibration camera module  70 , according to a third embodiment, is shown. The anti-vibration camera module  70  includes a lens module  702 , an image sensor  704 , and the actuator  100  of the first embodiment. The lens module  702  is received in the second receiving room  29  of the moveable member  20 . The image sensor  704  is aligned with the lens module  702  and fixed on a base (not shown) outside of the actuator  100 . The actuator  100  can drive the lens module  702  to move along X axis or Y axis to compensate for vibration. 
     It is to be understood that the image sensor  704  may be fixed to the actuator  100 , the actuator  100  can drive the image sensor  704  to move along the X axis or the Y axis to compensate for vibration. In other embodiment, the actuator  500  of the second embodiment may be used in the anti-vibration camera module  70 . 
     Advantages of anti-vibration camera module  70  of the third embodiment are similar to those of the above embodiment. 
     It is to be understood, however, that even though numerous characteristics and advantages of the present embodiments have been set fourth in the foregoing description, together with details of the structures and functions of the embodiments. The disclosure is illustrative only, and changes may be made in details, especially in matters of shape, size, and arrangement of parts within the principles of the disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.