Patent Publication Number: US-2015062424-A1

Title: Camera module and method for assembling same

Description:
FIELD 
     The present disclosure relates to a camera module and a method for assembling the camera module. 
     BACKGROUND 
     In recent years, anisotropic conductive films (ACFs) are used in assembling of camera modules. The camera module generally includes a lens module, a lens holder, an image sensor, a substrate, and a connecting board. In assembly, the lens modules a received in the lens holder, the image sensor is electrically connected to the substrate, a bottom end of the lens holder is attached on the substrate, and the substrate is electrically and mechanically connected to the connecting board by an ACF. In an assembling process, a pressing force should be applied on the camera module to process the substrate on the connecting board. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       The components of the drawing are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the embodiments of the present disclosure. 
         FIG. 1  is an exploded view of an exemplary embodiment of a camera module. 
         FIG. 2  is similar to  FIG. 1 , but showing the camera module from another angle. 
         FIG. 3  is an assembled view of the camera module of  FIG. 1 . 
         FIG. 4  is a flowchart of an exemplary embodiment of a method for assembling the camera module. 
         FIG. 5  is an isometric view of a substrate with a mounting adhesive distributed thereon. 
         FIG. 6  is an isometric view of the substrate of  FIG. 5  with an image sensor mounted thereon. 
         FIG. 7  is an isometric view of a lens holder and a lens module, the lens module being received into the lens holder. 
         FIG. 8  is an isometric view of the substrate and the image sensor of  FIG. 6  with a first adhesive distributed thereon. 
         FIG. 9  is an isometric view of an assembly of the lens holder and the lens module of  FIG. 7 , and the substrate of  FIG. 8 . 
         FIG. 10  is an isometric view of a connecting board with an ACF positioned thereon. 
         FIG. 11  is an isometric view of an assembly of the assembly of  FIG. 9  and the connecting board of  FIG. 10 . 
     
    
    
     DETAILED DESCRIPTION 
     The disclosure is illustrated by way of example and not by way of limitation in the figures of the accompanying drawings in which like references indicate similar elements. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references mean “at least one.” The references “a plurality of” and “a number of” mean “at least two.” 
       FIGS. 1-3  illustrate an exemplary embodiment of a camera module  100 . The camera module  100  includes a substrate  10 , an image sensor  20 , a lens holder  30 , a lens module  40 , and a connecting board  50 . 
     The substrate  10  includes a supporting surface  11  and a connecting surface  12  apposite to the supporting surface  11 . The supporting surface  11  supports the image sensor  20  thereon. The substrate  11  may have a circuit (not shown) for transmitting electrical power and electrical signals therethrough. The substrate  10  includes a number of first connecting pads  121  connecting to the circuit. In this embodiment, the substrate  10  is a rigid printed circuit board (PCB). 
     The image sensor  20  is substantially rectangular-shaped. Te image sensor  20  is electrically connected to the supporting surface  11  of the substrate  10 . The image sensor  20  includes a sensing surface  21 , two first side surfaces  22 , and two second side surfaces  23 . The first side surfaces  22  and the second side surfaces  23  are perpendicularly connected to the sensing surface  21 . The first side surfaces  22  are substantially parallel to each other, the second side surfaces  23  are substantially parallel to each other, and the first side surfaces  22  are substantially perpendicular to the second side surface  23 . In this embodiment, the image sensor  20  can be a charge-coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) sensor. 
     The lens holder  30  defines a chamber for receiving the lens module  40  and the image sensor  20 . The lens holder  30  includes a receiving end  31  and an assembling end  31  connected to the receiving end  31 . The lens holder  30  defines a receiving hole  311  in the receiving end  31 . In this embodiment, the receiving hole  311  is a substantially circular hole. A shape of the assembling end  31  corresponds to that of the substrate  10 . The assembling end  32  includes connecting surface  321  facing away from the receiving end  31 . 
     The lens module  40  captures images of objects and projects the images on the image sensor  20 . 
     The connecting board  50  is configured for connecting the substrate  10  to an outer circuit. The connecting board  50  includes a connecting portion  51  and an extending portion  52  connected to the connecting portion  51 . The connecting portion  51  includes a number of second connecting pads  511  corresponding to the first connecting pads  121  formed on the substrate  10 . The extending portion  52  includes a number of third connecting pads  521  for connecting to the outer circuit. In this embodiment, the connecting board  50  is a flexible PCB. 
     In assembly, the image sensor  20  is fixedly connected to the supporting surface  11  of the substrate  10 , in detail, the image sensor  20  and the substrate  10  are connected to each other by a thermosetting adhesive (not shown). After the image sensor  20  is connected to the substrate, a first adhesive  60  is distributed on each corner of the image sensor  20 . Each first adhesive  60  is distributed on a first surface  22 , a second surface  23 , and the supporting surface  11 . The lens module  40  is received in the receiving hole  311 , and the assembling end  32  is connected to the substrate  10 . The lens holder  40  is connected to the substrate  10  by a second adhesive  70 . In a process for assembling the lens holder on the substrate  10 , the second adhesive  70  is pre-distributed on the supporting surface  11  surrounding the image sensor. Alternatively, the second adhesive  70  can also be pre-distributed on the connecting surface  321  of the lens holder  30 . After the lens holder  40  is connected to the substrate  10 , the substrate  10  and the connecting board  50  are electrically and mechanically connected to each other by an ACF  80 . In detail, a force is applied for press the substrate  10  and the connecting board together each other, thus the first connecting pads  121  are electrically connected to the second connecting pads  511  by the ACF  80 , respectively. 
     In this embodiment, the first adhesive  60  and the second adhesive  70  are thermosetting adhesive. 
     Referring to  FIG. 4 , a flowchart of a method for assembling a camera module is presented in accordance with an example embodiment. The example method is provided by way of example, as there are a variety of ways to carry out the method. The method described below can be carried out using the configurations illustrated in  FIGS. 5-11 , for example, and various elements of these figures are referenced in explaining example method. Each block shown in  FIG. 4  represents one or more processes, methods or subroutines, carried out in the example method. Furthermore, the illustrated order of blocks is illustrative only and the order of the blocks can change according to the present disclosure. Additional blocks can be added or fewer blocks may be utilized, without departing from this disclosure. The example method can begin at block S 1 . 
     At block  001 , referring also to  FIG. 5 , a substrate  10  is provided, and a mounting adhesive  90  is distributed on a predetermined position of a surface of the substrate  10 . The predetermined position is a position to mount an image sensor. In this embodiment, the mounting adhesive  90  is thermosetting adhesive. 
     At block  002 , referring also to  FIG. 6 , an image sensor  20  is provided, and the image sensor  20  is mounted on the predetermined position of the substrate  10 . 
     At block  003 , the mounting adhesive  90  is solidified to adhere the image sensor  20  on the substrate  10 . 
     At block  004 , the image sensor  20  is electrically connected to the substrate  10 . In this embodiment, the image sensor  20  is electrically connected to the substrate  10  by a wire bonding process. 
     At block  005 , referring also to  FIG. 7 , a lens holder  30  and a lens module  40  are provided. The lens module  40  is mounted into the lens holder  30 . 
     At block  006 , referring also to  FIG. 8 , a first adhesive  60  is distributed on each corner of the image sensor  20 , and a second adhesive  70  is distributed on the surface of the substrate  10  surrounding the image sensor  20 . The first adhesive  60  is distributed on the surface of the substrate  10  and the side surfaces of the image sensor  20 . In this embodiment, the first adhesive  60  and the second adhesive  70  are thermosetting adhesive. 
     At block  007 , referring also to  FIG. 9 , the lens holder  30  is mounted on the substrate  10 , and the second adhesive  70  is sandwiched between the substrate  10  and the lens holder  30 . 
     At block  008 , the first adhesive  60  and the second adhesive  70  are solidified to fixedly connect the lens holder  30  and substrate  10  to each other and enhance a connection strength between the image sensor  20  and the substrate  10 . 
     At block  009 , referring also to  FIG. 10 , a connecting board  50  is provided, and an ACF  10  is positioned on a surface of the connecting board  50 . 
     At block  010 , referring also to  FIG. 11 , the substrate  10  is pressed on the position of the connecting board  50  with the ACF positioned thereon to make an electrical connection between the connecting board  50 . 
     Because the first adhesive  60  is distributed to connect the side surfaces of the image sensor  20  and surface of the substrate  10 , a connection strength between the image sensor  20  and the substrate  10  is enhanced, therefore, a warp of an edge of the image senor  10  relative to the substrate  10  in a pressing process can be avoided. Thus an assembling precision of the camera module is ensured. 
     It is believed that the present embodiments and their advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the scope of the disclosure or sacrificing all of its material advantages, the examples hereinbefore described merely being exemplary embodiments of the disclosure.