Abstract:
An Optical Image Stabilization unit including a wire connecting a housing to a holder module, a bobbin disposed inside the outer blade, a spring member disposed at the outer blade to support a movement of the bobbin in a direction along an optical axis, a first coil disposed at a periphery of the bobbin, a magnet moving the bobbin relative to the holder module by interacting with the first coil, a second coil moving the holder module relative to the housing by interacting with the magnet, a first solder portion disposed at a distal end of the wire to couple the wire to the housing, a second solder portion disposed at the other distal end of the wire to couple the wire to the holder module, and a buffer portion disposed at a part of the wire by being distanced from at least one of the first solder portion and the second solder portion to restrict a movement of the holder module relative to the housing by being coupled to at least one of the housing and the holder module.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a Continuation of co-pending U.S. application Ser. No. 14/583,422 filed on Dec. 26, 2014, which is a Continuation of U.S. application Ser. No. 14/203,263 filed on Mar. 10, 2014 (now U.S. Pat. No. 8,953,096 issued on Feb. 10, 2015), which is a Continuation of U.S. application Ser. No. 13/550,057 filed on Jul. 16, 2012 (now U.S. Pat. No. 8,698,952 issued on Apr. 15, 2014), which claims priority to Korean Patent Application No. 10-2011-0112190 filed on Oct. 31, 2011 and Korean Patent Application No. 10-2011-0115804 filed on Nov. 8, 2011, the entire disclosures of which are expressly incorporated by reference herein in their entireties. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a camera module. 
         [0004]    2. Background of the Related Art 
         [0005]    A camera module mounted on a small-sized electronic product may be frequently subject to a shock while in use. The camera module may be minutely shaken by a user&#39;s hand shaking during photographing. In view of the above problems, there is recently being disclosed a camera module having hand-shaking prevention means. 
         [0006]    For example, Korean Registration Patent No. 10-0741823 (registered on Jul. 16, 2007) discloses a method of installing a gyro sensor IC or an angular velocity sensor within a device on which a camera module is mounted, such as a mobile phone in order to correct a hand shaking phenomenon. 
         [0007]    If an additional angular velocity sensor is provided as described above, an additional sensor must be provided in order to implement the hand-shaking prevention function. Accordingly, there are problems in that manufacture costs are increased and an additional space where a hand-shaking prevention device will be constructed and installed must be provided in addition to the camera module. 
       SUMMARY OF THE INVENTION 
       [0008]    It is an object of the present invention to provide a camera module having an optical image stabilizer function. 
         [0009]    A camera module according to the present invention includes a first Printed Circuit Board (PCB) configured to have an image sensor mounted thereon; a housing unit disposed over the first PCB; a holder module spaced apart from a bottom surface within the housing unit at a specific interval and configured to have first coils wound on its outer circumferential face and to include at least lens therein; a second PCB combined with the bottom surface of the holder module; a third PCB disposed over the holder module; a plurality of wire springs each configured to have one end connected to the second PCB and the other end connected to the third PCB; and buffer units provided at the connection units of the wire springs and the third PCB and configured to surround the connection units of the wire springs and the third PCB. 
         [0010]    It is preferred that each of the buffer units include at least one injection hole formed to penetrate the third PCB around a through hole to which the wire spring is connected and a second wire spring through hole formed to penetrate the housing unit in a form taped downwardly so that the second wire spring through hole is placed on the same axis as a through hole formed in the third PCB; and formed to communicate with the injection hole through an upper opening. 
         [0011]    A camera module according to an exemplary embodiment of the present invention preferably may include an adhesive substance injected into the second wire spring through hole through the injection hole. 
         [0012]    Furthermore, the wire springs and the third PCB are coupled through the through hole. Here, it is preferred that the wire springs be connected to the top and bottom surfaces of the third PCB through the through hole by a connection substance and the connection substance include a conductive substance, such as lead. 
         [0013]    Furthermore, it is preferred that each of the buffer units include a pair of injection holes formed to penetrate the third PCB on both sides of a first wire spring through hole to which the wire spring is soldered and a second wire spring through hole formed to penetrate the housing unit in a form taped downwardly so that the second wire spring through hole is placed on an axis identical with the first wire spring through hole of the third PCB and to communicate with the pair of injection holes through an upper opening. 
         [0014]    Furthermore, a camera module according to an exemplary embodiment of the present invention further includes an adhesive substance injected into the second wire spring through hole through the pair of injection holes. It is preferred that the adhesive substance cover all the connection units formed within the second wire spring through hole and on the top of the third PCB. Here, the adhesive substance preferably may be epoxy. 
         [0015]    It is preferred that the second wire spring through hole include the upper opening provided in the housing unit in a funnel form taped downwardly and a wire spring support hole provided axially with the through hole. 
         [0016]    The second wire spring through hole may have a diameter equal to or greater than the through hole. 
         [0017]    It is preferred that the housing unit include a first housing disposed on the upper side of the first PCB; a second housing disposed on the upper side of the first housing and configured to have the third PCB disposed thereon; first and second permanent magnets interposed between the first and the second housings; and yoke each disposed between the first and the second permanent magnets or placed on the inside of the first and the second housing and configured to transfer magnetic force to the holder module. 
         [0018]    It is preferred that the yoke have a central part protruded toward the holder module. 
         [0019]    The second housing and the third PCB preferably may be fixed by a double-sided tape. 
         [0020]    Furthermore, a camera module according to an exemplary embodiment of the present invention preferably may include a shield can formed to have a through hole at a position where the connection unit of the third PCB and the wire spring corresponds to a lens module and to surround the housing unit. 
         [0021]    The holder module includes an outer blade formed to have first coils wound on its outer faces; a bobbin elastically supported by an elastic member on the upper side of the outer blade, disposed to be movable up and down within the outer blade, and configured to have a second coil wound on its outer circumferential face and to have at least one lens installed therein; and upper and lower elastic members disposed on respective upper and lower sides of the bobbin and configured to elastically support the bobbin against the outer blade. A space unit may be formed at the center of each of the first coils so that magnetic force is applied toward the second coil. 
         [0022]    The wire springs preferably may be made of metal material and conductive with the second and the third PCBs. 
         [0023]    The number of the wire springs preferably may be at least 6 so that a power source of two polarities for auto-focusing control and a power source of four polarities for optical image stabilizer are supplied to the holder module through connection between the wire springs and the second and the third PCBs. 
         [0024]    Furthermore, four pairs of the wire springs having the same length may be disposed at the respective corners of the holder module. 
         [0025]    A camera module according to another exemplary embodiment of the present invention includes a first Printed Circuit Board (PCB) configured to have an image sensor mounted thereon; a housing unit disposed over the first PCB; a holder module spaced apart from a bottom surface within the housing unit at a specific interval and configured to have first coils wound on its outer circumferential face and to include at least lens therein; a second PCB combined with the bottom surface of the holder module; a third PCB disposed over the holder module; and a plurality of wire springs each configured to have one end connected to the second PCB and the other end connected to the third PCB, wherein the wire springs and the third PCB are connected through through holes formed to penetrate the third PCB so that the top and bottom surfaces of the third PCB are connected by a connection substance. 
         [0026]    Meanwhile, a camera module according to the present invention may further include surface processing units formed at both ends of each of the wire springs and configured to increase bonding force between the wire springs and the second and the third PCBs. 
         [0027]    The surface processing unit may be coarsely formed by polishing a surface of the wire spring or may be formed by removing the coating film of the wire spring. 
         [0028]    In accordance with the present invention, the wire springs can be firmly connected to the connection units of the PCBs because the buffer units for absorbing load repeatedly applied to the wire springs are provided. 
         [0029]    Furthermore, although excessive force is applied to the wire springs in a process of assembling the lens module, the buffer units can absorb the excessive force. Accordingly, an assembly property can be improved, and the loss of parts due to poor assembly can be minimized. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0030]    Further objects and advantages of the invention can be more fully understood from the following detailed description taken in conjunction with the accompanying drawings in which: 
           [0031]      FIG. 1  is a schematic plan view of a camera module according to an embodiment of the present invention; 
           [0032]      FIG. 2  is a sectional view of the camera module taken along line A-A of  FIG. 1 ; 
           [0033]      FIGS. 3 and 4  are side views of the camera module according to the embodiment of the present invention; 
           [0034]      FIG. 5  is an enlarged view of a part B of  FIG. 2  according to a first embodiment of the present invention; 
           [0035]      FIG. 6  is an enlarged view of a part B of  FIG. 2  according to a second embodiment of the present invention; 
           [0036]      FIG. 7  is an enlarged view of a part B of  FIG. 2  according to third and fourth embodiments of the present invention; 
           [0037]      FIG. 8  is a diagram showing shows the surface processing units of a wire spring according to the third embodiment of the present invention; and 
           [0038]      FIG. 9  is a diagram showing shows the surface processing units of a wire spring according to a fourth embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0039]    Hereinafter, some exemplary embodiments of the present invention are described in detail with reference to the accompanying drawings. 
         [0040]      FIG. 1  is a schematic plan view of a camera module according to an embodiment of the present invention,  FIG. 2  is a sectional view of the camera module taken along line A-A of  FIG. 1 ,  FIGS. 3 and 4  are side views of the camera module according to the embodiment of the present invention, and  FIG. 5  is an enlarged view of a part B of  FIG. 2  according to a first embodiment of the present invention. 
         [0041]    As shown in  FIG. 1  showing the schematic plan view and  FIG. 2  showing the schematic side view of line A-A in  FIG. 1 , the camera module according to the present invention includes a first Printed Circuit Board (hereinafter referred to as a PCB)  10 , a housing unit  20 , a holder module  30 , a second PCB  40 , a third PCB  50 , wire springs  60 , and buffer units  100 . 
         [0042]    It is preferred that an image sensor  11  be mounted approximately on the central part of the first PCB  10 . Elements for driving the image sensor  11  may be disposed in the first PCB  10  or a plurality of terminal units for supplying power and outputting information from the image sensor  11  may be provided in the first PCB  10 . 
         [0043]    The housing unit  20  is disposed over the first PCB  10 , and it forms the framework of the camera module. In accordance with an exemplary embodiment of the present invention, the housing unit  20  includes a first housing  21 , a second housing  22 , pairs of first and second permanent magnets  23  and  24 , and a plurality of yokes  25 . 
         [0044]    The first housing  21  is a base and is disposed on the top of the first PCB  10  and spaced apart from the image sensor  11  at a specific interval. A filter member for filtering an image phase incident on the image sensor  11  may be further included in the first housing  21  as occasion demands. 
         [0045]    The second housing  22  is disposed on the top of the first housing  21  and is configured to cover the first housing  21 . An opening is formed approximately at the center of the second housing  22  so that an image can be transferred to the image sensor  11 . The third PCB  50  is adhered and fixed to the upper lateral face of the second housing  22  using a fixing member to be described later, such as a double-sided tape or an adhesive, but not limited thereto. In some embodiments, however, an additional third housing, such as a casing or a shield can, may be provided, and the third PCB  50  may be fixed to the inside of the additional third housing using the fixing member according to a product design. If the third housing is provided, the third housing may press and support the third PCB  50  without an additional fixing member. 
         [0046]    The first and the second permanent magnets  23  and  24  are interposed between the first and the second housings  21  and  22  and are configured to apply magnetic force to the holder module  30 . It is preferred that the first and the second permanent magnets  23  and  24  have the same size. Furthermore, the first and the second permanent magnets  23  and  24  and the yoke  25  may be disposed on the inside of the first and the second housing  21  and  22 , if possible, within a design tolerance limit. 
         [0047]    Meanwhile, if the size of the first and the second permanent magnets  23  and  24  is increased, OIS driving is increased even by low current. If the first and the second permanent magnets  23  and  24  are configured to have a specific size, OIS driving is increased as current flowing into first and the second coils  31   a  to  31   d  and  32   a  disposed at positions corresponding to the first and the second permanent magnets  23  and  24  is increased. Consequently, OIS driving becomes better according to an increase of the first and the second permanent magnets  23  and  24 , but it is preferred that the first and the second permanent magnets  23  and  24  have an optimized size within a design tolerance limit. 
         [0048]    Each of the yokes  25  is interposed between each of the pairs of first and the second permanent magnets  23  and  24 . Furthermore, the central portion of the yoke  25  is configured to have a protruded shape so that the pair of first and second permanent magnets  23  and  24  may apply magnetic force to the internal space of the holder module  30 . It is preferred that the yoke  25  be configured to the same width as the pair of first and second permanent magnets  23  and  24 , the center of the yoke  25  be protruded in a specific size, and the pair of first and second permanent magnets  23  and  24  and the yoke  25  have an approximately ‘T’ shape. 
         [0049]    The holder module  30  is spaced apart from the bottom surface of the inside of the housing unit  20  and is formed of an outer blade  31  and a bobbin  32 . The holder module  30  may perform a pendulum movement in the front/rear, left/right, and diagonal directions with it dangled from the wire springs  60 . 
         [0050]    Spring members  35  and  36  are provided in the upper and lower parts of the outer blade  31 , respectively. The outer blade  31  is elastically supported by the spring member  35  so that the bobbin  32  is moved up and down. 
         [0051]    As shown in  FIG. 1 , a total of four first coils  31   a  to  31   d  are wound on the four outer faces of the outer blade  31 , respectively, and the central part of each of the four outer faces of the outer blade  31  on which the first coils  31   a  to  31   d  are wound is perforated without a coil. Each of the yokes  25  is disposed at a position corresponding to the perforated space unit, and thus the yoke  25  may be partially inserted into the space unit. 
         [0052]    The second PCB  40  may be fixed to the bottom of the outer blade  31  using a fixing member  33 , such as a double-sided tape or an adhesive. The outer blade  31  is dangled from the plurality of wire springs  60  so that the outer blade  31  can move in the front/rear and left/right directions or in a diagonal line according to an interaction between the magnetic force of the first and the second permanent magnets  22  and  23  and the first coils  31   a , as indicated by an arrow of  FIG. 2 . Furthermore, the outer blade  31  is spaced apart from the bottom surface of the first housing  21  at a specific interval. 
         [0053]    Furthermore, a plurality of spring through holes  37  may be provided in the outer blade  31  so that the wire springs  60  are connected to the second PCB  40  through the spring through holes  37 . 
         [0054]    The bobbin  32  is disposed within the outer blade  31  so that it is movable up and down. At least one lens  34  is installed within the bobbin  32 . The second coil  32   a  is wound on the outer circumferential face of the bobbin  32 . The second coil  32   a  performs an operation of raising up and lowering the bobbin  32  through an interaction with the magnetic force applied through the perforated spaces without the first coils  31   a  to  31   d  of the outer blade  31  through the yokes  25 . As the size of the yoke  25  increases, AF driving may become better, but may be changed according to an optimal design value. It is possible to automatically control the focus of an image transferred to the image sensor  11  through the raising action of the bobbin  32 . 
         [0055]    The second PCB  40  is disposed at the bottom surface of the outer blade  31  as described above and is connected to the wire springs  60  so that it can supply a power source to the first and the second coils  31   a  to  31   d  and  32   a . This connection method may include any method if soldering or other conductive substances may be used. That is, the connection units w′ of the second PCB  40  are connected to the first coils  31   a  to  31   d , respectively, and the second coil  32   a , as shown in,  FIG. 2 . Thus, a power source supplied through the wire springs  60  is transferred to the first and the second coils  31   a  to  31   d  and  32   a , thus forming electromagnetic force. 
         [0056]    Here, the second coil  32   a  may be directly connected to the second PCB  40 , or the second coil  32   a  may be connected to the lower spring  36  and the lower spring  36  may be then connected to the second PCB  40  as shown in  FIG. 2 . 
         [0057]    The third PCB  50  is fixed to the top of the second housing  22  using the fixing member, such as a double-sided tape or an adhesive member, as described above. A power source transferred through the terminal unit  52  of the third PCB  50  connected to the first PCB  10  is transferred to the second PCB  40  through the wire springs  60  connected to the second PCB  40 . This connection method may include any method if soldering or other conductive substances may be used. 
         [0058]    The third PCB  50  may be provided to cover the walls of the first and the second housings  21  and  22  on one side, as shown in  FIGS. 3 and 4 . Here, a window  55  may be formed in a surface of the third PCB  50  where the third PCB  50  faces the first and the second permanent magnets  23  and  24  and the yoke  25  in order to avoid interference therebetween. 
         [0059]    The window  55  functions to prevent the third PCB  50  from being influenced by coupling portions because the first and the second permanent magnets  23  and  24  and the yoke  25  are directly adhered to a shield can  70  (described later) by using the fixing means, such as epoxy. 
         [0060]    Meanwhile, a flexible PCB (FPCB), a PCB, or a rigid FPCB integration type (R-FPCB) may be used as each of the second PCB  40  and the third PCB  50 , but not limited thereto. Any board may be used as the second PCB  40  and the third PCB  50  if the board enables electrical connection. 
         [0061]    Each of the wire springs  60  has both ends connected to the second and the third PCBs  40  and  50 . Here, one end of the wire spring  60  is connected to a pad  51  formed in the third PCB  50  as shown in  FIG. 5 . A through hole  53  through which the wire spring  60  passes is formed at the center of the pad  51 . In this case, a connection method may include any method if soldering or other conductive substances may be used. Meanwhile, a Solder Register (SR) is provided around the pad  51 , thus protecting a surface of the third PCB  50 . The area of the pad  51  may be connected by opening the SR so that the area is conductive. 
         [0062]    The wire spring  60  connected at the pad  51  as described above supplies the power source from the terminal unit  52  to the second PCB  40 , so that the first and the second coils  31   a  to  31   d  and  32   a  may interact with the first and the second permanent magnets  23  and  24 . 
         [0063]    Furthermore, the other end of the wire spring  60  is connected to the second PCB  40 , provided at the bottom surface of the outer blade  31 , through the spring through hole  37  formed in the outer blade  31 , as shown in  FIG. 2 . As in the third PCB  50 , the other end of the wire spring  60  is connected at a pad (not shown) formed in the second PCB  40 , although not shown. A through hole (not shown) through which the wire spring  60  passes is formed at the center of the pad (not shown). In this case, a connection method may include any method if soldering or other conductive substances may be used. In this construction, the outer blade  31  may be dangled from the wire springs  60  and may be spaced apart from the bottom surface of the first housing  21 . In this case, the outer blade  31  performs a pendulum movement according to an interaction between the first coils  31   a  to  31   d  and the first and the second permanent magnets  23  and  24 . Accordingly, the vibration of the outer blade  31  due to hand shaking can be corrected by the interaction between the first coils  31   a  to  31   d  and the first and the second permanent magnets  23  and  24 . To this end, it is preferred that the wire spring  60  be made of metal material that has elasticity enough to withstand a shock and conductivity. 
         [0064]    Meanwhile, as the thickness of the wire spring  60  is reduced, optical image stabilizer motility becomes better even at a low current, but may be changed according to an optimal design value. It is preferred that the thickness of the wire spring  60  be several μm to several hundreds of μm, more preferably, 1 to 100 μm. 
         [0065]    Furthermore, it is preferred that the number of wire springs  60  be at least six. It is necessary to supply a power source of two polarities for auto-focusing control and a power source of four polarities for optical image stabilizer to the holder module  30  through connection between the wire springs  60  and the second and the third PCBs  40  and  50 . 
         [0066]    In accordance with an exemplary embodiment of the present invention, it is preferred that four pairs of the wire springs  60  having the same length are disposed at the respective corners of the holder module  30  in order to keep the balance, as shown in  FIGS. 1 and 2 . 
         [0067]    Meanwhile, if an additional third housing, such as the shield can  70 , is included as shown in  FIG. 2 , the windows  55  for covering the walls of the first and the second housings  21  and  22  are formed in the third PCB  50  in order to avoid the coupling parts because the first and the second permanent magnets  23  and  24  and the yokes  25  are fixed to the shield can  70  using epoxy, as described above. 
         [0068]    If the shield can  70  is omitted, the first and the second permanent magnets  23  and  24  and the yokes  25  may be attached and fixed within the third PCB  50 . In some embodiments, the windows  55  may be formed in the third PCB  50  as described above, and the first and the second permanent magnets  23  and  24  and the yokes  25  may be inserted into the windows  55 . Reinforcement may be additionally performed outside the third PCB  50  using a shielding tape. 
         [0069]    Buffer units  100  function to absorb a shock and repeated load applied to the wire springs  60  by surrounding connection units w where the wire springs  60  are connected to the third PCB  50 . 
         [0070]    In accordance with an exemplary embodiment of the present invention, each of the buffer units  100  includes an injection hole  110  and a second wire spring through hole  120 . 
         [0071]    The injection hole  110  is formed around the through hole  53  to which the wire spring  60  passing through the third PCB  50  is soldered. In accordance with the first embodiment of the present invention, the number of injection holes  110  may be one, as shown in  FIG. 5 . 
         [0072]    The second wire spring through hole  120  is provided in the second holder  22 . The second wire spring through hole  120  includes an upper opening  121  and a support hole  122 . 
         [0073]    The upper opening  121  has a structure that is taped downwardly. It is preferred that the upper opening  121  have a conical funnel shape that is downwardly tapered, as shown in  FIGS. 5 and 6 . The support hole  122  is formed in the same axis as the through hole  53 . It is preferred that the support hole  122  have a diameter equal to or greater than the through hole  53 . 
         [0074]    It is preferred that the through hole  53  have a diameter slightly greater than the wire spring  60 . When the wire spring  60  is connected at the pad  51  formed in the third PCB  50 , a connection substance  101 , such as soldering or another conductive substance, flows out through the through hole  53 . The connection substance  101  may be connected to the wire spring  60  in the top and bottom surfaces of the third PCB  50 , as shown in  FIGS. 5 and 6 . 
         [0075]    It is preferred that the diameter of the support hole  122  be slightly greater than the diameter of the wire spring  60 . The diameter of the support hole  122  may be equal to or greater than the diameter of the through hole  53 . That is, the diameter of the support hole  122  may be designed so that the wire spring  60  does not interfere with the second holder  22  near the support hole  122  through contact with the second holder  22 . 
         [0076]    A shown in  FIG. 5 , an adhesive substance  130  is injected through the injection hole  110  and then filled in the internal space unit of the second wire spring through hole  120 . The adhesive substance  130  may further cover the connection unit w of the third PCB  50 . The adhesive substance  130  filled in the second wire spring through hole  120  may absorb a shock and load transferred to the connection unit w of the wire spring  60  and the third PCB  50  and may prevent the wire spring  60  from being shaken within the upper opening  121  of the second wire spring through hole  120 . Epoxy may be used as the adhesive substance  130 , but not limited thereto. Any material that may support elasticity through adhesion may be used as the adhesive substance  130 . 
         [0077]    In accordance with a second embodiment of the present invention, the buffer unit  100  may be configured like in the first embodiment, but a pair of the injection holes  110  may be provided in the buffer unit  100 . In this case, the pair of the injection holes  110  may be disposed on both sides of the through hole  53  or may be symmetrically disposed each other, but not limited to the positions. 
         [0078]    In this case, the adhesive substance  130  injected through the pair of injection holes  110  may fully cover not only the inside of the upper opening  121  of the second wire spring through hole  120 , but also the connection unit w formed on the top of the third PCB  50 , as shown in  FIG. 4 . 
         [0079]    In accordance with this construction, there are additional effects that the connection unit w of the third PCB  50  exposed at the top can be prevented from being damaged by an external shock and the connection unit w is insulated. 
         [0080]    Meanwhile, in a common assembly process, after the bobbin  32  and the outer blade  31  are combined, the second housing  22 , the second and the third PCBs  40  and  50 , and the wire springs  60  are coupled, the bobbin  32  including a lens barrel is combined, the first housing  21  is connected, and the first housing  21  is then mounted on the first PCB  10  by using a jig. Alternatively, the permanent magnets and the yokes may be combined before the first housing  21  is connected. The sequence of the above assembly may be changed as occasion demands. In other words, the assembly may be directly performed in equipment without a jig. In this process, although force for inserting and combining the bobbin  32  including the lens barrel is excessively great and the connection units w are adversely affected by the excessive force, the buffer units  100  may absorb the excessive force. 
         [0081]    In other words, the transformation energy of the buffer unit  100  absorbs load that is generated in the wire spring  60  around the connection unit w of the wire spring  60  and the third PCB  50  and thus pulled in the direction of gravity and load generated when the wire spring  60  is shaken left and right, as shown in  FIGS. 2, 5, and 6 . 
         [0082]    Accordingly, a problem that the connection task has to be performed again or that a damaged product cannot be used because the connection unit w is broken during the assembly process can be avoided. It is thus possible to produce a reliable camera module. 
         [0083]    Surface processing units  1100  are formed at both ends of each of the wire springs  60 , thereby improving a coupling property between the second and the third PCBs  40  and  50  and the wire spring  60 . 
         [0084]    In accordance with third and fourth embodiments of the present invention, each of the surface processing units  1100  may be coarsely formed by polishing a surface of the wire spring  60  as shown in  FIG. 5  or may be formed by partially removing a coating film formed on the surface of the wire spring  60  using a method, such as corrosion, as shown in  FIG. 6 . If the surface processing unit  1100  is formed as described above, bonding force between lead and the wire spring  60  can be improved when a soldering process using lead as the connection substance is performed. 
         [0085]    Meanwhile, a second wire through hole  120  is provided in the second holder  22 , as shown in  FIG. 7 . The second wire through hole  120  includes an upper opening  121  and a wire spring support hole  122 . 
         [0086]    The upper opening  121  has a conical funnel shape that is downwardly tapered. The wire spring support hole  122  is formed on the same axis as the first wire through hole  53 . It is preferred that the wire spring support hole  122  have a diameter equal to or greater than the first wire through hole  53 . 
         [0087]    Here, the diameter of the first wire through hole  53  may be slightly greater than the diameter of the wire spring  60 . The diameter of the first wire through hole  53  may be designed so that, when the wire spring  60  is connected to the pad  51  formed in the third PCB  50 , a connection substance, such as soldering or other conductive substances, flows down through the first wire through hole  53  and the connection substance is then connected and fixed to the wire spring  60  on the top and bottom surfaces of the third PCB  50 . 
         [0088]    Furthermore, the diameter of the wire spring support hole  122  may be slightly greater than the diameter of the wire spring  60 . The wire spring support hole  122  may have a diameter equal to or greater than the first wire through hole  53 . That is, the diameter of the wire spring support hole  122  may be designed so that the wire spring  60  does not interfere with the second holder  22  near the support hole  122  through contact with the second holder  22 . 
         [0089]    In accordance with this construction, the wire springs  60  can be combined with the second and the third PCBs  40  and  50  more firmly. Furthermore, a reliability problem (e.g., the separation or disconnection of the wire springs  60  that may occur owing to external force, such as a drop) can be improved. 
         [0090]    That is, the surface processing units  1100  increase the frictional force of the connection units w and w′ between the wire springs  60  and the second and the third PCBs  40  and  50 , so that the surface processing units  1100  withstand load in the direction of gravity applied to the wire springs  60  at the connection units w and w′ and load that may occur when the wire springs  60  are shaken left and right, as shown in  FIGS. 2, 8, and 9 . 
         [0091]    Accordingly, a problem that the connection task has to be performed again or that a damaged product cannot be used because the connection unit w is broken during the assembly process can be avoided. It is thus possible to produce a more reliable camera module. 
         [0092]    Meanwhile, the surface processing unit  1100  may be formed only at the end of one side of the wire spring  60 , although not shown. That is, the surface processing unit  1100  may be formed only at the connection unit w with the third PCB  50  to which heavy load is repeatedly applied or at the connection unit w′ with the second PCB  40 . 
         [0093]    Meanwhile, the shield can  70  may be further provided to have a through hole at a position corresponding to the lens module  30  near the connection units w of the third PCB  50  and the wire springs  60  and configured to surround the housing units  21  and  22 . In this case, the third PCB  50  may be attached and fixed to the inside of the shield can  70  as described above. Meanwhile, the shield can  70  is not a requisite and may be omitted according to constructions of the housing units  21  and  22 . 
         [0094]    Meanwhile, as shown in  FIG. 2 , in order to fix the shield can  70  to the first housing  21 , a hook unit  80  may be provided at each of the four faces or at one or more faces. The position of the hook unit  80  may be within a range in which the center or corner design is allowed. The number of hook units  80  may be one or more. 
         [0095]    The hook unit  80  may include a hook  81  protruded into the first housing  21  and a hook hole  82  formed to penetrate the shield can  70  facing the hook  81 , and an opposite construction is possible as an occasion demands. 
         [0096]    The embodiments of the present invention described above and shown in the drawings should not be construed as limiting the technical spirit of the present invention. The scope of the present invention is restricted by only the claims, and a person having ordinary skill in the art to which the present invention pertains may improve and modify the technical spirit of the present invention in various forms. Accordingly, the modifications and modifications will fall within the scope of the present invention as long as they are evident to those skilled in the art.