Abstract:
A lens module is disclosed. The lens module includes a lens barrel including a first barrel wall extended horizontally and a second barrel wall extended from the first barrel wall; a lens group including at least one lens, the lens includes a first slope; a stop on the first barrel wall and forming a light hole for the lens, and a pressing ring attached to the stop. The first barrel wall of the lens barrel includes a second slope abutting against the first slope for ensuring the concentricity.

Description:
FIELD OF THE DISCLOSURE 
     The present utility relates to a lens module, particularly to the lens module of mobile phones, digital cameras, PDAs, note books and other electronic products. 
     BACKGROUND 
     As the photographic technology and the electronic products with photographic function are developed in recent years, optical camera lens module is used widely in many kinds of products. In order to follow the current trend that the size of electronic products is smaller, the lens module shall also be smaller. 
     In the existing technology, the lens module comprises a lens barrel having a central axis, lenses installed in the lens barrel and a stop clamped between the lenses. The lens barrel comprises a first barrel wall extended horizontally, i.e., at right angles to the central axis and a second barrel wall extended from the first barrel wall along the central axis direction. A light hole is created on the first barrel wall for the lens. However, the light hole on the first barrel wall requires the barrel wall with a certain thickness, therefore, the wall thickness of the barrel wall is increased, and the height and weight of the entire lens module is increased. It will be more difficult to produce the lens barrel. In the existing technology, a slope is also provided on the first barrel wall at the position of the light hole, so, the difficulty of production is increased further. 
     For this reason, it is necessary to provide a novel lens module to overcome the shortcomings above. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Many aspects of the 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 disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
         FIG. 1  is an illustration of a lens module in accordance with an exemplary embodiment of the present disclosure. 
         FIG. 2  is an illustration of a lens barrel of the lens module in  FIG. 1 . 
         FIG. 3  is an illustration of the lens group in the lens module in  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure will be described in detail below with reference to the attached drawings and an exemplary embodiment thereof. 
     As shown in  FIG. 1 , a lens module  100  in accordance with an exemplary embodiment of the present disclosure comprises a lens barrel  1  having a central axis O, a lens group  2  (see  FIG. 3 ) installed in the lens barrel  1 , a stop  3  installed on the lens barrel  1 , and a pressing ring  4  attached to the stop  3 . 
     As shown in  FIG. 2 , the lens barrel  1  comprises a first barrel wall  11  extended horizontally and a second barrel wall  12  extended downward from the first barrel wall  11 . A receiving space  13  is formed by the first barrel wall  11  and the second barrel wall  12 . The lens barrel  1  is provided with a lug  14  extended from the inner surface of the first barrel wall  11  to the central axis of the lens barrel  1 . A groove  15  is created by the lug  14  and the inner surface of the lens barrel  1 . The groove  15  communicates with the receiving space  13 . The stop  3  is located partially in the groove  15 . The lug  14  on the first barrel wall  11  creates a hole  111  which is connected to the receiving space  13 . The lug  14  is provided with a second slope  112 . 
     As shown in  FIG. 3 , the lens group  2  comprises a first lens  21  and a second lens  22  which is stacked on the first lens  21 . The lens group  2  in this embodiment comprises two lenses. In other embodiments, the lens group can comprise one lens or more than two lenses. The first lens  21  comprises a first surface  211  far from the second lens  22  and a second surface  212  opposite to the first surface. The first lens  21  comprises a protruding central portion  213  and a peripheral portion  214  around the protruding central portion  213 . The first surface  211  of the first lens  21  comprises, in turn from external to internal, a first flat surface  215  extended horizontally, a first slope  216  against the second slope  112 , a second flat surface  217  extended horizontally, and a first optical surface  218 . The first flat surface  215 , the first slope  216  and the second flat surface  217  are located at the peripheral portion  214  of the first lens  21 . The first optical surface  218  is a circular arc surface and is located on the protruding central portion  213  of the first lens  21 . The inclination of the first slope  216  and the inclination of the second slope  112  are the same so that the first slope  216  and the second slope  112  fit in fully with each other. A gap is created between the second flat surface  217  and the stop  3 . In other embodiments, the second flat surface  217  and the stop  3  can fit in fully with each other. The peripheral portion  214  of the first lens  21  is clamped between the first barrel wall  11  and the second lens  22 . The optical axis of the first lens  21 , the optical axis of the second lens  22  and the central axis of the lens barrel  1  are aligned in one straight line. 
     The stop  3  is located partially in the groove  15  on the first barrel wall  11  of the lens barrel  1  and extended horizontally and inwardly beyond the lug  14 . The stop  3  compromises a light hole  31  for the protruding central portion  213  of the first lens  21 . The stop  3  is a hollow ring. The aperture of the light hole  31  is smaller than the aperture of the hole  111 . The central axis of the stop  3 , the optical axis of the lens group  2  and the central axis of the lens barrel  1  are aligned in one straight line. The stop  3  contacts the first optical surface  218  of the first lens  21 . 
     The press ring  4  is installed in the groove  15  of the lens barrel  1  and is pressed on the stop  3 , thereby the stop  3  is fixed more stably. A third slope  41  is provided at the edge of the press ring  4 . The third slope  41  and the inner surface of the lens barrel  1  create the glue groove  42 . The press ring  4  is fixed by glue  5  on the lens barrel  1 , and then the stop  3  is clamped between the press ring  4  and the lens barrel  1 . The press ring  4  can also be installed with an interval to the lens barrel  1  in horizontal direction, so that a gap is created between the press ring and the lens barrel. A glue groove for receiving the glue is created by the outer wall of the press ring and the inner surface of the lens barrel and the stop. The stop can be fixed directly by glue on the lens barrel. The press ring  4  is made of plastic or metal. 
     When assembling the lens module  100 , the lens barrel  1  and the stop  3  are installed first. The stop  3  is installed in the groove  15  of the lens barrel  1 . The press ring  4  is pressed on the stop  3  and fixed by glue  5  in the glue groove  41  created by the inner surface of the first barrel wall  11 . The central axis of the stop  3  and the central axis of the lens barrel  1  are aligned in one straight line. The first lens  21  is installed in the lens barrel  1 . The first flat surface  215  of the first lens  21  is abutted against the first barrel wall  11  of the lens barrel  1 . The first slope  216  of the first lens  21  is abutted against the second slope  112  of the first barrel wall  11 . The fit between the slopes ensures the concentricity between the first lens  21  and the lens barrel  1 . The first lens  21  can be pressed precisely into the lens barrel  1 . The first optical surface  218  of the first lens  21  is extended beyond the light hole  31  of the stop  3 . The edge of the first lens  21  has press fit with the inner surface of the second barrel wall  12  of the lens barrel  1 . The second lens  22  is installed under the first lens  21 . The edge of the second lens  22  has press fit with the inner surface of the second barrel wall  12  of the lens barrel  1 . Certainly, the first lens  21  and the second lens  22  can be also put directly into the lens barrel  1  and no press fit on the inner surface of the lens barrel  1 . At last, the second lens  22  is fixed further by glue in the lens barrel  1 . At this point, the assembling of the lens module  100  is finished. 
     The stop  3  can block off stray light, moreover, the stop  3  can create directly the light hole  31  for the protruding central portion  213  of the first lens  21 . The wall thickness of the first barrel wall  11  can be very thin, thereby the height and weight of entire lens module  100  are reduced, conforming to the miniaturization trend of equipment at present. At the same time, the lens barrel  1  with smaller wall thickness is convenient to be produced with high yield of qualified products and other advantages. 
     It is to be understood, however, that even though numerous characteristics and advantages of the present embodiment have been set forth in the foregoing description, together with details of the structures and functions of the embodiment, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.