Abstract:
A camera module includes a voice coil motor comprising a fixing assembly, a movable assembly, an elastic member connecting the movable assembly to the fixing assembly, and a pivoting member located between the fixing assembly and the movable assembly; a lens assembly and an image sensor received in the movable assembly; a plurality of Hall sensors capable of detecting movement distances of the movable assembly; and a control module comprising a current distributor, and a processor electrically connected to the Hall sensors. Wherein when shaking occurs, the housing is driven to move along the central axis and at the same time is rotated a desired angles pivoting on the pivoting member, the processor configured for calculating rotated angles of the movable assembly base on movement distances of the movable assembly relative to the respective Hall sensors.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The present disclosure relates to camera modules, and particularly, to an anti-shake camera module. 
         [0003]    2. Description of Related Art 
         [0004]    Lens modules and image sensors are key components of camera modules. In normal use of a camera module, light rays coming from an object, transmit through the lens module along a predetermined path and fall on a central region of the image sensor. That is, an image plane of the object is precisely on the image sensor, and thus a clear image is obtained. However, inadvertent shaking of the camera module may occur during the time that an image is captured. When this happens, either or both of the lens module and the image sensor may move slightly relative to the object. In such case, the light rays from the object may not accurately fall on the image sensor. That is, the image plane of the object may not be precisely on the image sensor, resulting in a blurry image. 
         [0005]    What is needed, therefore, is a camera module which can overcome the above shortcomings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    Many aspects of the present camera module can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present camera module. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
           [0007]      FIG. 1  is a schematic view of a camera module in accordance with an embodiment. 
           [0008]      FIG. 2  is an exploded view of the camera module of  FIG. 1 . 
           [0009]      FIG. 3  is a cross-sectional view of the camera module of  FIG. 1 , taken along line 
           [0010]      FIG. 4  is a cross-sectional view of the camera module of  FIG. 1 , taken along line IV-IV. 
           [0011]      FIGS. 5 and 6  are similar to  FIGS. 3 and 4 , respectively, but each showing a movable assembly of the camera module could be rotated according to need. 
           [0012]      FIG. 7  is similar to  FIG. 3 , but showing that a deflection of light occurs when shaking of the camera module occurs. 
           [0013]      FIG. 8  shows the movable assembly of the camera module is rotated to anti-shake. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0014]    Embodiments of the present camera module will now be described in detail below and with reference to the drawings. 
         [0015]    Referring to  FIGS. 1 and 2 , an exemplary camera module  10 , includes a voice coil motor  100 , a lens assembly  200 , an image sensor  300 , a circuit board  400 , a first Hall sensor  510 , a second Hall sensor  520 , a third Hall sensor  530  and a control module  600 . 
         [0016]    The voice coil motor  100  includes a fixing assembly  110 , a movable assembly  120 , an elastic member  130  connecting the movable assembly  120  to the fixing assembly  110 , a first magnetic member  141 , a second magnetic member  151 , a third magnetic member  142 , a fourth magnetic member  152 , a fifth magnetic member  143 , a sixth magnetic member  153 , and a pivoting member  160  located between the fixing assembly  110  and the movable assembly  120 . 
         [0017]    The fixing assembly  110  includes a frame  111  and a fastening plate  112 . The frame  111  has a quadrate configuration, and includes a first sidewall  1111 , a second sidewall  1112  opposite to the first sidewall  1111 , a third sidewall  1113 , and a fourth sidewall  1114  opposite to the third sidewall  1113 . A receiving space  1115  is defined in the frame  111 , surrounded by the first, second, third and fourth sidewalls  1111 ,  1112 ,  1113 , and  1114 . A first opening  1116  is formed in the second sidewall  1112 , a second opening  1117  is formed in the third sidewall  1113 , and a third opening  1118  is formed in the fourth sidewall  1114 . A first cutout  1119  is formed in the first sidewall  1111  at a top of the first sidewall  1111 . Two second cutouts  1110  are formed in the third sidewall  1113  and the fourth sidewall  1114 , respectively, and two protrusions  1100  are formed at the two corners of the first sidewall  1111 . 
         [0018]    The fastening plate  112  includes a first bar  1124 , a second bar  1123 , a third bar  1122  interconnecting the first bar  1124  and the second bar  1123 , an extending portion  1121  and two recesses  1126 . The first, second and third bars  1124 ,  1123 , and  1122  cooperatively form a “U” configuration, and the two recesses  1125  are formed at the bottom of the “U” configuration. The extending portion  1121  extends downwards from a bottom of the third bar  1122 , and the extending portion  1121  is substantially perpendicular to the “U” configuration. The first and second bars  1124  and  1123  are engaged with the second cutouts  1110 , the recesses  1126  are engaged with the protrusions  1100 , and the third bar  1122  together with the extending portion  1121  is engaged in the cutout  1119 , thereby fastening the fastening plate  112  to the frame  111 . A spherical recess  1125  is formed in a surface of the extending portion  1121 , which faces the receiving space  1115  of the frame  111 . 
         [0019]    The movable assembly  120  includes a housing  121  and a connecting block  122 . The housing  121  is received in the receiving space  1115  of the frame  111 . The housing  121  includes a first sidewall  1211 , an opposite second sidewall  1212 , a third sidewall  1213 , an opposite fourth sidewall  1214 , and a cover  1215 . A housing space  1216  is defined in the housing  121 , and surrounded by the first, second, third and fourth sidewall  1211 ,  1212 ,  1213 ,  1214  and the cover  1215 . The housing space  1216  receives the lens assembly  200  therein. 
         [0020]    A cross sectional shape of the connecting block  122  is similar to “L”. The connecting block  122  includes a first arm  1223  fixed to the cover  1215  of the housing  121 , and a second arm  1221  fixed to the first sidewall  1211 . The second arm  1221  faces the fastening plate  112  and is spaced apart from the fastening plate  112 . A spherical recess  1222  is formed in the second arm  1221 , and the spherical recess  1222  aligns with the spherical recess  1125  of the fastening plate  112 . The pivoting member  160  is a ball bearing, and is received the spherical recesses  1222  and  1125 . 
         [0021]    The elastic member  130  includes a first portion  131 , a second portion  132 , a third portion  133 , a first connecting portion  134  connecting the first portion  131  to the third portion  133 , and a second connecting portion  135  connecting the first portion  131  to the second portion  132 . Two through holes  138  are formed in the first and second portions  131  and  132 , respectively. The first portion  131  is fixed to the cover  1215 , the second portion  132  is sandwiched between the second bar  1123  of the fastening plate  112  and the fourth sidewall  1114  of the frame  111 . The third portion  133  is sandwiched between the first bar  1124  of the fastening plate  112  and the third sidewall  1113  of the frame  111 . The through holes  138  are engaged with the protrusions  1100  of the frame. The connecting block  122  may contact with the elastic member  130 . The first and second connecting portions  134  and  135  are substantially “U” shaped. The openings of the “U” configuration of the first and second connecting portions  134  and  135  both face to the second sidewall  1112  of the frame  111 . A gap is maintained between any adjacent two of the portions. The first and second connecting portions  134  and  135  provide elasticity for the first portion  131 . 
         [0022]    The first magnetic member  141 , the third magnetic member  142 , and the fifth magnetic member  143  are electromagnetic members, e.g., coils of wire. The first magnetic member  141  is retained in the first opening  1116 , the third magnetic member  142  is retained in the second opening  1117 , and the fifth magnetic member  143  is retained in the third opening  1118 . 
         [0023]    The second magnetic member  151  is fixed to the second sidewall  1212 , the fourth magnetic member  152  is fixed to the third sidewall  1213 , and the sixth magnetic member  153  is fixed to the fourth sidewall  1214 . The second, fourth and sixth magnetic members  151 ,  152 , and  153  each include a top permanent magnet  1511 ,  1521 , and  1531  and a bottom permanent magnet  1512 ,  1522 , and  1532 , respectively. In the present embodiment, each of the top permanent magnets  1511 ,  1521 , and  1531  has a single S polarity side adjacent to the housing  121 , and a single N polarity side opposite to the S polarity side. Each of the bottom permanent magnet  1512 ,  1522 , and  1532  has a single N polarity side adjacent to the housing  121 , and a single S polarity side opposite to the N polarity side. Each of the top permanent magnet  1511 ,  1521 , and  1531  and the bottom permanent magnet  1512 ,  1522 , and  1532  can be made by a magnetization method. With the above configuration, when a current is applied to each of the first magnetic member  141 , the third magnetic member  142  and the fifth magnetic member  143 , the second magnetic member  151 , the fourth magnetic member  152  and the sixth magnetic member  153  cooperatively are able to move along the Z axis as defined. That is, under the driving force given by all of the second magnetic members  151 , the fourth magnetic member  152  and the sixth magnetic member  153 , the housing  121  moves substantially along the Z axis. 
         [0024]    The image sensor  300  is mounted at a bottom of the housing  121 , facing the lens assembly  200 . The circuit board  400  is mounted at a bottom of the frame  111 , and has the first Hall sensor  510 , second Hall sensor  520 , third Hall sensor  530  and the control module  600  mounted thereon. 
         [0025]    The first Hall sensor  510  aligns with the second magnetic member  151 , the second Hall sensor  520  aligns with the fourth magnetic member  152 , and the third Hall sensor  530  aligns with the sixth magnetic member  153 . The first, second and third Hall sensors  510 ,  520 , and  530  each work based on the Hall Effect. A voltage output by each of the first, second and third Hall sensors  510 ,  520 , and  530  are determined by the intensity of the magnetic field applied thereon. That is, a distance between the first Hall sensor  510  and the second magnetic member  151  would influence the voltage output of the first Hall sensor  510 . A distance between the second Hall sensor  520  and the fourth magnetic member  152  would influence the voltage output by the second Hall sensor  520 , and a distance between the third Hall sensor  530  and the sixth magnetic member  153  would influence the voltage output by the third Hall sensor  530 . 
         [0026]    The control module  600  is configured to receive signals from the first, second and third Hall sensors  510 ,  520 , and  530 , and then supply currents to the first magnetic member  141 , third magnetic member  142  and the fifth magnetic member  143 . The control module  600  may include a current distributor  602  and a processor  603  therein. The current distributor  602  is electrically connected to the first magnetic member  141 , third magnetic member  142  and the fifth magnetic member  143 . The processor  603  is electrically connected to the first, second and third Hall sensors  510 ,  520 , and  530 . 
         [0027]    Referring also to  FIGS. 3 and 4 , a predetermined distance between the first Hall sensor  510  and the second magnetic member  151  is D 1 , a predetermined distance between the second Hall sensor  520  and the fourth magnetic member  152  is D 2 , and a predetermined distance between the third Hall sensor  530  and the sixth magnetic member  153  is D 3 . The Hall sensor  510  is spaced apart from a central axis of the fixing assembly  110  a distance L 1 , and the second Hall sensor  520  is spaced apart from the third Hall sensor  530  a distance L 2 . 
         [0028]    Referring also to  FIGS. 5 and 6 , when one of the second magnetic members  151 , the fourth magnetic member  152  and the sixth magnetic member  153  is subject to a force substantially along a direction of the Z axis, i.e., the corresponding one of the first magnetic member  141 , the third magnetic member  142  and the fifth magnetic member  143  has a current applied, due to the pivoting member  160 , the housing  121  together with the lens assembly  200  may rotate certain angles about the Y axis or the X axis. The distance between the first Hall sensor  510  and the second magnetic member  151  may change to D 1 ′, the distance between the second Hall sensor  520  and the fourth magnetic member  152  may change to D 2 ′, and the distance between the third Hall sensor  530  and the sixth magnetic member  153  may change to D 3 ′. A ratio between the L 1  and a difference between the D 1 ′ and the D 1  may substantially reflect the rotated angles about the X axis, and a ratio between the L 2  and a difference between the D 3 ′ and the D 2 ′ may substantially reflect the rotated angles about the Y axis. The processor  603  is in charge of the ratio calculation. That is, the rotated angles of the housing  121  can be monitored. 
         [0029]    It is understood that when two and not all of the second magnetic members  151 , the fourth magnetic member  152  and the sixth magnetic member  153  are subject to a force substantially along a direction of the Z axis, due to the pivoting member  160 , the housing  121  together with the lens assembly  200  may also rotate certain angles about the Y axis or the X axis. 
         [0030]    Referring also to  FIG. 7 , in application, when a shaking of the entire camera module  10  occurs, the shaking may lead to rotations of the entire camera module  10  along the X axis and the Y axis, thus resulting a deflection of light when it passes through the lens assembly  200 . 
         [0031]    To work in the anti-shake function, for example, assuming that the rotations result in rotating the housing  121  along with the lens assembly  200  and the image sensor  300 , to move upwards along the Z axis. The current distributor  602  of the control module  600  distributes a current to the corresponding first magnetic member  141 , the third magnetic member  142 , and the fifth magnetic member  143  to move the housing  121  downwards along the Z axis. That is, it rotates the movable assembly  120  to the desired angles, then the light will not deflect when it passes through the lens assembly  200  (see  FIG. 8 ). That is, the camera module  10  has the anti-shake function. 
         [0032]    It is understood that the above-described embodiments are intended to illustrate rather than limit the disclosure. Variations may be made to the embodiments and methods without departing from the spirit of the disclosure. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the disclosure.