Abstract:
A photoelectric coupling module includes a substrate, a photoelectric unit, and a lens module. The substrate carries at least two alignment marks for correct and absolute positioning of the lens module on the substrate. The photoelectric unit is positioned on the substrate. The lens module defines at least two through holes aligned with the alignment marks.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The present disclosure relates to photoelectric technologies and, particularly to a photoelectric coupling module. 
         [0003]    2. Description of Related Art 
         [0004]    Photoelectric coupling modules may include a lens module, optical fibers, and a photoelectric unit. The lens module optically couples the optical fibers with the photoelectric unit. However, if the photoelectric unit is misaligned with lenses of the lens module because of manufacturing imprecision, an optical coupling efficiency of the photoelectric coupling module is decreased. 
         [0005]    Therefore, it is desirable to provide a photoelectric coupling module that can overcome the limitations described. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a schematic view of a photoelectric coupling module in accordance with an exemplary embodiment. 
           [0007]      FIG. 2  is an exploded and schematic view of the photoelectric coupling module of  FIG. 1 . 
           [0008]      FIG. 3  is a cross-sectional view taken along a line III-III of  FIG. 1 . 
           [0009]      FIG. 4  is a cross-sectional view taken along a line V-V of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0010]    Embodiments of the disclosure will be described with reference to the drawings. 
         [0011]      FIGS. 1-4  show a photoelectric coupling module  10  according to an exemplary embodiment. The photoelectric coupling module  10  includes a substrate  11 , a photoelectric unit  12 , and a lens module  13 . 
         [0012]    The substrate  11  is a printed circuit board and includes a bearing surface  111 . At least two alignment marks  112  are formed on the bearing surface  111 . The alignment marks  112  can be recesses defined in the bearing surface  111 , protrusions protruding from the bearing surface  111 , or coatings coated on the bearing surface  111 . In the embodiment, the number of the alignment marks  112  is two. The alignment marks  112  can be integrally molded with the substrate  11 , or be separately formed and then combined. 
         [0013]    The photoelectric unit  12  is positioned on the bearing surface  111 , and includes at least one light emitter  121 , such as a laser diode, and at least one light receiver  122 , such as a photo diode. The at least one light emitter  121  is electrically connected to the substrate  11 , and converts electronic signals into light signals. The at least one light receiver  122  is electrically connected to the substrate  11 , and receives and converts light signals into electronic signals. The number of the at least one light emitter  121  is equal to the number of the at least one light receiver  122 . The at least one light emitter  121  and the at least one light receiver  122  are linearly arranged between the two alignment marks  112 . In the embodiment, the photoelectric unit  12  includes one light emitter  121  and one light receiver  122 . 
         [0014]    The lens module  13  is substantially rectangular and is made of transparent material, such as plastic or glass. The lens module  13  is supported on the substrate  11 . The lens module  13  includes a top surface  131 , a bottom surface  132 , and a side surface  133 . The bottom surface  132  is opposite to the top surface  131 , and the side surface  133  is substantially perpendicularly connected between the top surface  131  and the bottom surface  132 . 
         [0015]    The lens module  13  defines an elongated first recess  1311  in the top surface  131  which is substantially parallel to a line between the alignment marks  112 . A cross-section of the first recess  1311  is triangular. The first recess  1311  includes an inner surface  1312  substantially perpendicular to the top surface  131  and a reflection surface  1313  tilting about 45 degrees up from the inner surface  1312 . 
         [0016]    The lens module  13  defines a substantially rectangular second recess  1321  in the bottom surface  132 . The second recess  1321  includes a lower surface  1322  substantially parallel to the top surface  131 . At least two first lenses  1123  are formed on the lower surface  1322 , located within an orthogonal projection of the reflection surface  1313  onto the bottom surface  132 . In the embodiment, the first lenses  1323  are convex lenses. The first lenses  1323  are linearly arrayed and are axially directed towards the reflection surface  1313 . The number of the first lenses  1323  is equal to the total number of the at least one light emitter  121  and the at least one light receiver  122 . In the embodiment, the lens module  13  includes two first lenses  1323 . 
         [0017]    The lens module  13  defines a substantially rectangular third recess  1331  in the side surface  133 . The third recess  1331  includes an end surface  1332  parallel with the side surface  133 . At least two second lenses  1333  are formed on the end surface  1332 , located within an orthogonal projection of the reflection surface  1313  onto the side surface  133 . In the embodiment, the second lenses  1333  are convex lenses. The second lenses  1333  are linearly arrayed and axially directed towards the reflection surface  1313 . The second lenses  1333  are received in the third recess  1331 . 
         [0018]    The number of the second lenses  1333  is equal to the number of the first lenses  1323 . An optical axis of each second lens  1333  is perpendicular to an optical axis of each first lens  1323 . The optical axes of the first lenses  1323  cross the optical axes of the second lenses  1333  on the reflection surface  1313 . In the embodiment, the lens module  13  includes two second lenses  1337 . 
         [0019]    The lens module  13  defines at least two through holes  134  running through the top surface  131  and the bottom surface  132 . In the embodiment, the number of the through holes  134  is two. The two through holes  134  are positioned at ends of the first recess  1311 . The two through holes  134  are linearly arrayed to be parallel to and correspond with the alignment marks  112 . The through holes  134  communicate with the second recess  1321 . 
         [0020]    In assembly, the light emitter  121  and the light receiver  122  are mounted on the bearing surface  111  by a surface-mount technology (SMT). The lens module  13  is positioned on the substrate  11 . The alignment marks  112  align with the through holes  134 . The alignment marks  112  are wholly exposed from the through holes  134  when the respective optical axes of the first lenses  1323  are correctly aligned with the light emitter  121  and the light receiver  122 . 
         [0021]    During the signal-transmission process, the light emitter  121  emits light rays to the first lenses  1323  along a direction perpendicular to the bottom surface  1322 . The light rays are converged by the first lenses  1323 , and are projected onto the reflection surface  1313 . The reflection surface  1313  reflects the light rays to the second lenses  1337 . 
         [0022]    During the same process, the light rays enter into the lens module  13  through the second lenses  1333 . The light rays are converged by the second lenses  1333 , and are projected onto the reflection surface  1313 . The reflection surface  1313  reflects the light rays to the first lenses  1323 . The light rays are converged by the first lenses  1323 , and are projected to the light receiver  122 . The light receiver  122  converts the light rays into electronic signals, and the electronic signals are transmitted to the substrate  11 . 
         [0023]    Particular embodiments are shown and described by way of illustration only. The principles and the features of the present disclosure may be employed in various and numerous embodiments thereof without departing from the scope of the disclosure as claimed. The above-described embodiments illustrate the scope of the disclosure but do not restrict the scope of the disclosure.