Abstract:
A photoelectric converting module includes a circuit board, at least one light emitting/receiving unit and an optical coupler both mounted on the circuit board. Each light emitting/receiving unit includes a light emitter and a light receiver, the light emitter and the light receiver each include at least one positioning projection. The optical coupler includes positioning parts to engage with the positioning projections for aligning the optical coupler with the light emitting/receiving unit precisely.

Description:
FIELD 
       [0001]    The present disclosure relates to communications technology, particularly to optical communications. 
       BACKGROUND 
       [0002]    A photoelectric converting module usually includes a circuit board, a light emitting/receiving unit mounted on the circuit board, and an optical coupler. The optical coupler must be precisely aligned with the light emitting/receiving unit. Yet, it is not easy to precisely align the optical coupler with the light emitting/receiving unit during assembly. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0003]    Many aspects of the embodiments 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. 
           [0004]      FIG. 1  is a diagrammatic, top plan view of a photoelectric converting module according to an exemplary embodiment of the present disclosure. 
           [0005]      FIG. 2  is a cross-sectional view of the photoelectric converting module taken along II-II line of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0006]    It will be appreciated that for simplicity and clarity of illustration, where appropriate, reference numerals have been repeated among the different figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the embodiments described herein. However, it will be understood by those of ordinary skill in the art that the embodiments described herein can be practiced without these specific details. In other instances, methods, procedures, and components have not been described in detail so as not to obscure the related relevant feature being described. Also, the description is not to be considered as limiting the scope of the embodiments described herein. The drawings are not necessarily to scale and the proportions of certain parts may be exaggerated to better illustrate details and features of the present disclosure. 
         [0007]    Several definitions that apply throughout this disclosure will now be presented. 
         [0008]    The term “substantially” is defined to be essentially conforming to the particular dimension, shape, or other feature that the term modifies, such that the component need not be exact. For example, “substantially cylindrical” means that the object resembles a cylinder, but can have one or more deviations from a true cylinder. The term “comprising,” when utilized, means “including, but not necessarily limited to”; 
         [0009]    it specifically indicates open-ended inclusion or membership in the so-described combination, group, series, and the like. 
         [0010]    The present disclosure is described in relation to a light emitting device and a backlight module including the light emitting device. 
         [0011]      FIGS. 1 and 2  illustrate a photoelectric converting module  100  including a circuit board  10 , at least one light emitting/receiving unit  20 , and an optical coupler  30 . 
         [0012]    In this embodiment, there are two light emitting/receiving units  20 . Each light emitting/receiving unit  20  includes a light emitter  21  and a light receiver  22 . The light emitter  21  is a laser diode, and the light receiver  22  is a photodiode. The light emitter  21  and the light receiver  22  are located on the circuit board  10  along a straight line and are electrically connected with the circuit board  10 . 
         [0013]    The light emitter  21  includes a bottom surface  211 , a top surface  212  opposite to and in parallel with the bottom surface  211 , and a side surface  213  connecting the top surface  212  to the bottom surface  211 . The top surface  212  defines an optical window  214  at a center thereof. The light emitter  21  further includes two positioning projections  215 , adjacent to two opposite sides of the optical window  214  and located on the top surface  212 . The positioning projections  215  can be made of a plastic, a metal, a glass, or other material. In this embodiment, the positioning projections  215  are made of a metal, such as copper, aluminum, nickel, or silver and are formed on the top surface  212  by means of electro-plating. 
         [0014]    A structure of the light receiver  22  is similar to a structure of the light emitter  21  and a detailed description of the light receiver  22  is omitted. 
         [0015]    The optical coupler  30  includes a substrate  31 , at least one first converging lens unit  32 , and at least one second converging lens unit  33  and a reflector  34 . 
         [0016]    The substrate  31  is substantially rectangular, and defines a receiving space  311  for receiving the light emitting/receiving unit  20 . The receiving space  311  includes a top wall  312  opposite to the circuit board  10  and a side wall  313  perpendicularly connected to the top wall  312 . The top wall  312  includes an inner surface  312   a  facing the circuit board  10 . Four pairs of positioning parts  35  are formed on the inner surface  312   a.  Each positioning part  35  defines a groove  351  for receiving one of the positioning projections  215 , to precisely align the optical coupler  30  with the light emitting/receiving unit  20 . The side wall  313  includes an outer surface  313   a.    
         [0017]    Each first converging lens unit  32  includes two first converging lenses  321 . Each first converging lens  321  is aligned with one of the optical windows  214  and is located between two positioning parts  35 . Each second converging lens unit  33  includes two second converging lenses  331 . The second converging lenses  331  are formed on the outer surface  313   a  and each corresponds to a first converging lens  321 . 
         [0018]    The reflector  34  is inserted into the top wall  312  for changing a transmission direction of light incident on the reflector  34 . The light emitting/receiving unit  20 , the optical window  214 , the first converging lens  321 , the reflector  34 , and the second converging lens  331  cooperatively form an optical path. 
         [0019]    As the photoelectric converting module  100  includes engaging the positioning projections  215  and positioning parts  35 , the optical coupler  30  can be precisely aligned with the light emitting/receiving unit  20 . 
         [0020]    It will be understood that the above particular embodiments are shown and described by way of illustration only. The principles and the features of the present disclosure can be employed in various and numerous embodiments thereof without departing from the scope of the disclosure. The above-described embodiments illustrate the scope of the disclosure but do not restrict the scope of the disclosure.