Patent Publication Number: US-2011075277-A1

Title: Camera module

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure relates to optical imaging, and particularly to a camera module. 
     2. Description of Related Art 
     A typical camera module includes a holder and a barrel. In assembly, the barrel is screwed to the holder. Friction between internal threads of the holder and external threads of the barrel may produce some particles, in assembly. The particles may fall into optical elements (e.g., lenses, an infrared-cut filter) in the barrel, thus deteriorating imaging quality of the camera module. 
     Therefore, a new camera module is desired to overcome the above-mentioned problem. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Many aspects of the present embodiment 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 embodiment. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
         FIG. 1  is an exploded perspective view of a camera module according to an exemplary embodiment. 
         FIG. 2  is a cross-sectional view of the assembled camera module of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     An embodiment will now be described in detail below with reference to the drawings. 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. 
     Referring to  FIGS. 1-2 , a camera module  20  according to an exemplary embodiment is shown. The camera module  20  includes a barrel  201 , a holder  202 , and a plurality of optical elements (e.g., lenses; not shown) received in the barrel  201 . 
     The barrel  201  includes a first threaded part  2011  and a first cylindrical part  2012  in that order from the object side to the image side. The first threaded part  2011  has an opening  2010  defined in one end and a plurality of external threads  2013  formed on the outer cylindrical surface. The opening  2010  allows light incident into the barrel  201 . An outer diameter of the first threaded part  2011  is less than that of the first cylindrical part  2012 . It is noteworthy that in other embodiments, the outer diameter of the first threaded part  2011  is equal to that of the first cylindrical part  2012 . 
     The barrel  201  further includes a plurality of recesses  2017  defined in one end surface facing the image side. In assembly of the camera module  20 , the barrel  201  can be held in place by a tool (not shown), such as a clamp used on the recesses  2017 . 
     The holder  202  is hollow and includes a through hole. The barrel  201  is received in the through hole. The holder  202  includes a second threaded part  2023 , a second cylindrical part  2024 , and a base  2021  from the object side to the image side. The complete outer cylindrical surface of the first cylindrical part  2012  is in contact with the inner cylindrical surface of the second cylindrical part  2024 . The second threaded part  2023  includes a plurality of internal threads  2022 . The barrel  201  engages with the holder  202  via the external threads  2013  and the internal threads  2022 . An inner diameter of the second cylindrical part  2024  is larger than an outer diameter of the second threaded part  2023 . The outer cylindrical surface of the first cylindrical part and the inner cylindrical surface of the second cylindrical part are both smooth surfaces. 
     In assembly, the barrel  201  is inserted into the through hole of the holder  202  in a direction pointing from the second cylindrical part  2024  to the second threaded part  2023 , and then is screwed into the holder  202 . Because the inner cylindrical surface of the second cylindrical part  2024  is in full contact with the outer cylindrical surface of the first cylindrical part  2012 , most of small particles produced in screwing are sealed in a gap (not labeled) between the barrel  201  and the holder  202 , and prevented from polluting optical elements in the barrel  201 . 
     While certain embodiment have been described and exemplified above, various other embodiment from the foregoing disclosure will be apparent to those skilled in the art. The present disclosure is not limited to the particular embodiment described and exemplified but is capable of considerable variation and modification without departure from the scope and spirit of the appended claims.