Patent Publication Number: US-2012044412-A1

Title: Camera module and assembly method the same

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure relates to an image capture, and more particularly, to a camera module used for an electronic device and an assembly method the same. 
     2. Description of Related Art 
     Camera modules are widely used in electronic devices such as personal digital assistants, mobile phones, portable computers, and others. 
     A typical cameral module includes a circuit board, a holder, a lens module, an image sensor chip, and a filter. The holder includes a sleeve and a base connected to an end of the sleeve. The lens module is received in the sleeve. The holder is mounted on the circuit board. The base is a hollow chamber. The image sensor chip is electrically fixed to the first circuit board and received on the base. The filter is received in the base corresponding to the image sensor chip. Incident light is capable of passing through the lens module and the filter in that order, and finally projecting on the image sensor. The camera module further includes a plurality of electronic elements and integrated circuits disposed on the circuit board. 
     However, a distribution density of the electronic elements and the integrated circuits on the circuit board is very high such that the circuit board must be large, and as a result, the volume of the camera module is also large. 
     Therefore, there is room for improvement within the art. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The components in the drawings are not necessarily drawn to scale, the emphasis instead being positioned upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the views. 
         FIG. 1  is cross section of a first embodiment of a camera module. 
         FIG. 2  is cross section of a second embodiment of a camera module. 
         FIG. 3  is a flowchart of an assembly method for a camera module, such as, for example, that of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , a first embodiment of a camera module  200  includes a holder  21 , a lens module  23 , a first circuit board  25 , an image sensor chip  27 , a second circuit board  29 , and a filter  31 . The lens module  23  is partially received in the holder  21 . The holder  21  is mounted on the first circuit board  25 . The image sensor chip  27 , the second circuit board  29 , and the filter  31  are received in the holder  21 . 
     The holder  21  includes a sleeve  212  and a base  214  connected to an end of the sleeve  212 . The sleeve  212  is hollow and substantially cylindrical, and forms an internal thread  2121  on an inner surface of the sleeve  212 . The base  214  is substantially rectangular and defines a receiving portion  2141 . The receiving portion  2141  is a substantially rectangular groove depressed from an end of the base  214  away from the sleeve  212 . The receiving portion  2141  communicates with the sleeve  212 . The base  214  includes a fixing end  2143  at an end of the base  214  away from the sleeve  212 . 
     The lens module  23  includes a lens barrel  231  and at least one lens  233  received in the lens barrel  231 . The lens barrel  231  forms an external thread  2312  on an outer surface of the lens barrel  231 . The lens module  23  is threaded into the sleeve  212  of the holder  21 . 
     The holder  21  is mounted on the first circuit board  25  by fixing the fixing end  2143  to the first circuit board  25 . The first circuit board  25  may be a rigid printed circuit board, a flexible printed circuit board, or a rigid flex printed circuit board. The image sensor chip  27  is received in the receiving portion  2141 , and electrically fixed to a middle portion of the first circuit board  25  by wires  272  corresponding to the lens  233 . The image sensor chip  27  may be a charge coupled device (CCD), or complementary metal oxide semiconductor (CMOS). 
     The second circuit board  29  is smaller than the first circuit board  25 . The second circuit board  29  defines a light port  292  in a middle portion thereof. The camera module  200  further includes a plurality of adhesive blocks  294 . The second circuit board  29  is received in the receiving portion  2141  and fixed to the first circuit board  25  by the adhesive blocks  294  with the light port  292  corresponding to the lens  233 . The image sensor chip  27  is positioned between the first circuit board  25  and the second circuit board  29 . It should be pointed out that the second circuit board  29  may be fixed to the image sensor chip  27  alternatively. The second circuit board  29  is electrically connected to the first circuit board  25  by wires  296 . The second circuit board  29  may also be a rigid printed circuit board, a flexible printed circuit board, or a rigid flex printed circuit board. 
     The filter  31  is fixed to a side of the second circuit board  29  away from the image sensor chip  25  and shields the light port  292 . Incident light passes through the lens  233  of the lens module  23  and the filter  31  in order, and is incident on the image sensor chip  27 . The camera module  200  further includes a plurality of electronic elements and integrated circuits (not shown) selectively disposed on the first circuit board  27  or the second circuit board  29 . It should be pointed out that the filter  31  may be fixed to the base  214  directly, as long as the filer  31  corresponds to the image sensor chip  27  and the lens  233 . 
     The camera module  200  further includes a substrate  33  attached to a side surface of the first circuit board  25  away from the holder  21  to support the first circuit board  25 . 
     The electronic elements and integrated circuits of the camera module  200  may be selectively disposed on the first circuit board  27  or on the second circuit board  29 . As a result the camera module  200  has a compact configuration with a relatively low distribution density of electronic elements and integrated circuits, and the camera module  200  may be easily manufactured. 
     Referring to  FIG. 2 , a second embodiment of a camera module  300  differs from the first embodiment of the camera module  200  only in that the camera module  300  includes two second circuit boards  39 . The two second circuit boards  39  are spaced apart to cooperatively define a gap  392  corresponding to the image sensor chip  41 . The filter  41  interconnects the two second circuit boards  39 . 
       FIG. 3  shows an assembly method of a camera module such as, for example, that of the first embodiment. The steps are not limited in the illustrated order and some steps may be performed simultaneously or partially simultaneously. 
     In step S 501 , a substrate  33  and a first circuit board  25  are provided, and the first circuit board  25  is attached to a side surface of the substrate  33 . A part of the electronic elements and integrated circuits of the camera module  200  are disposed on the first circuit board  25 . 
     In step S 503 , an image sensor chip  27  is provided, and fixed to a side surface of the first circuit board  25  opposite to the substrate  33 . 
     In step S 505 , the image sensor chip  27  is electrically connected to the first circuit board  25 . In the illustrated embodiment, the image sensor chip  27  is connected to the first circuit board  25  by wires  272 . 
     In step S 507 , a second circuit board  29  is provided, the second circuit board  29  defines a light port  292  at a middle portion thereof. Other parts of the electronic elements and integrated circuit of the camera module  200  are disposed on the second circuit board  29 . 
     In step S 509 , the second circuit board  29  is fixed to a side of the first circuit board  25  with the image sensor chip  27  positioned between the first circuit board  25  and the second circuit board  29 . The light port  292  corresponds to the image sensor chip  27 . In the illustrated embodiment, the second circuit board  29  is fixed to the first circuit board  25  by the adhesive blocks  294  to space the first circuit board  25  and the second circuit board  29  apart. 
     In step S 511 , the second circuit board  29  is electrically connected to the first circuit board  25  by wires  296 . 
     In step S 513 , a filter  31  is provided, and fixed to a side of the second circuit board  29  away from the first circuit board  25 . The filter  31  shields the light port  292 . 
     In step S 515 , a lens module  23  is provided. The lens module  23  includes a lens barrel  231  and at least one lens  233  received in the lens barrel  231 . The lens barrel  231  forms an external thread  2312  on the outer surface of the lens barrel  231 . 
     In step S 517 , a holder  21  is provided. The holder  21  includes a sleeve  212  and a base  214  connected to an end of the sleeve  212 . The sleeve  212  is substantially hollow and cylindrical, and forms an internal thread  2121  thereon. The lens module  23  is threaded into the sleeve  212  of the holder  21 . The base  214  defines a receiving portion  2141  communicating with the sleeve  212 . 
     In step S 519 , the base  214  is mounted on the first circuit board  29  with the sleeve  212  corresponding to the filter  31 . The image sensor chip  27 , the second circuit board  29 , and the filter  31  are received in the receiving portion  2141 . 
     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 spirit and scope of the disclosure or sacrificing all of its material advantages.