Abstract:
An adapter having a plurality of receptacles in which optical connector plugs are housed, and connected to the optical connector plug housed in any of the receptacles. The adapter has a member made of a conductive material and disposed between the plurality of receptacles. The member has a opening in its central portion, and a grounding piece formed in a desired position.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to an adapter.  
         BACKGROUND OF THE INVENTION  
         [0002]    Conventionally, in an optical module, for example, a semiconductor laser module, the intensity of electromagnetic waves radiated from the semiconductor laser module has been negligible because the optical power output from the semiconductor laser has been small.  
           [0003]    However, with the advancement of optical communication technologies, recent optical modules are required to provide high power, so that large currents flow in electronic circuits contained therein, thereby causing an increasingly higher intensity of electromagnetic waves radiated to the outside. Thus, some optical modules may exert electromagnetic influences on electronic circuits disposed therearound.  
           [0004]    In an optical module which is provided with a receptacle at an end for connection with an optical connector, a shielding measure is taken for removing such electromagnetic influences.  
           [0005]    However, no adapters used in connecting optical connectors to each other have been provided with such shielding measures as mentioned above. Moreover, since the adapters are mounted on wiring boards and the like, there is a need for taking such shielding measures as mentioned above simply and inexpensively.  
         SUMMARY OF THE INVENTION  
         [0006]    It is an object of the present invention to provide an adapter which makes it possible to take shielding measures simply and inexpensively to remove electromagnetic influences.  
           [0007]    To achieve the above object, an adapter of the present invention has a plurality of receptacles in which optical connector plugs are housed and is connected to the optical connector plug housed in any of the receptacles. The adapter comprises a member made of a conductive material and disposed between the plurality of receptacles. The member has an opening in its central portion, and a grounding piece formed in a desired position.  
           [0008]    Also, to achieve the above object, an adapter of the present invention has a plurality of receptacles in which optical connector plugs are housed and is connected to the optical connector plug housed in any of the receptacles. The adapter comprises a housing made of a conductive material and attached to at least one of the plurality of receptacles.  
           [0009]    The above and other objects, features and advantages of the present invention will be clearer from the following detailed description based on the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    [0010]FIG. 1 is an exploded perspective view illustrating a first embodiment of an adapter according to the present invention;  
         [0011]    [0011]FIG. 2 is an exploded perspective view illustrating an exemplary modification to the adapter of FIG. 1;  
         [0012]    [0012]FIG. 3 is an exploded perspective view illustrating another exemplary modification to the adapter of FIG. 1;  
         [0013]    [0013]FIG. 4 is a perspective view illustrating a second embodiment of the adapter according to the present invention, before a housing is attached to one receptacle of the adapter;  
         [0014]    [0014]FIG. 5 is a perspective view illustrating the adapter of FIG. 4 with the housing attached to one receptacle of the adapter; and  
         [0015]    [0015]FIG. 6 is a perspective view illustrating the adapter of FIG. 4 with housings attached to both receptacles of the adapter. 
     
    
     DETAILED DESCRIPTION  
       [0016]    In the following, a first embodiment of an adapter according to the present invention will be described in detail with reference to FIGS. 1 through 3.  
         [0017]    An adapter  1  comprises a conductive plate  3  between two receptacles  2 . Here, optical connector plugs are housed in the receptacles  2  of the adapter  1  from both sides and connected with each other.  
         [0018]    Each of the receptacles  2  is molded of a synthetic resin such as polybutyleneterephthalate (PBT), polyphenylenesulphide (PPS) or the like, and comprises a prismatic body  2   a ; an opening  2   b  formed in a front portion of the body  2   a  for receiving a plug or a multifiber connector, for example, an MPO (Multifiber Push-On) connector or the like which is inserted through the opening  2   b ; and flanges  2   c  formed in a rear portion of the body  2   b  and extending on both sides of the body  2   b . Each of the flanges  2   c  is formed with a screw hole  2   d  for fixation to a panel of a wiring board, not shown. Here, the panel of the wiring board is made of a conductive metal, and is grounded beforehand.  
         [0019]    The conductive plate  3  is molded in plate shape using a conductive resin which comprises, for example, carbon powder, or conductive metal powder such as copper, aluminum, silver or the like uniformly mixed in a synthetic resin such as polybutyleneterephthalate (PBT), polyphenylenesulphide (PPS) or the like, or a conductive metal such as copper, aluminum, silver or the like. The conductive plate  3  is formed with an opening  3   a  in its central portion, and is provided with grounding pieces  3   b  on both sides, one of which protrudes to the front and the other to the rear of the conductive plate  3 . The conductive plate  3  is formed with screw holes  3   c  through which screws are inserted on both sides of the opening  3   a . The opening  3   a  is formed slightly larger than a cover which covers a ferrule of the MPO connector. Each of the grounding pieces  3   b  is formed with a screw hole  3   d  in a position corresponding to the screw hole  3   c  for fixation to a panel of a wiring board, not shown.  
         [0020]    The adapter  1  is constructed as described above, and is integrated by inserting each of the flanges  2   c  into each grounding piece  3   b , positioning the two receptacles  2  on both surfaces of the conductive plate  3 , matching the corresponding screw holes  2   d  and  3   d , depositing portions of the receptacles  2 , or bonding them using an adhesive or the like. Then, the adapter  1  is disposed in an opening (not shown) formed in the panel for mounting the adapter  1 , and the adapter  1  is fixed to the panel by screws inserted through the screw holes  2   d ,  3   c ,  3   d . In this manner, the conductive plate  3  of the adapter  1  is grounded through the panel.  
         [0021]    With the foregoing structure, even if the adapter  1  is connected to a multifiber connector which is connected to a high power optical module, the conductive plate  3  allows strong electromagnetic waves to escape to the ground through the panel, thereby making it possible to remove the electromagnetic influences simply and inexpensively.  
         [0022]    In the adapter  1  described above, a conductive plate  4  illustrated in FIG. 2 may be used in place of the conductive plate  3 . Specifically, the conductive plate  4  is formed, in place of the opening  3   a , with an opening  4   a , in its central portion, which is slightly larger than the profile of the ferrule of the MPO connector and smaller than the opening  3   a , and is provided with grounding pieces  4   b  on both sides, one of which protrudes to the front side and the other to the rear of the conductive plate. The conductive plate  4  is formed with screw holes  4   c  on both sides of the opening  4   a , through which screws are inserted. Each of the grounding pieces  4   b  is formed with a screw hole  4   d  at a position corresponding to the screw hole  4   c  for fixation to a panel of a wiring board, not shown.  
         [0023]    Alternatively, as a conductive plate  5  illustrated in FIG. 3, the adapter  1  may be provided with grounding pieces  5   b  on both sides of an opening  5   a , both of which protrude on one side of the conductive plate  5 . In this event, as is the case with the conductive plates  3 ,  4 , the conductive plate  5  is formed with screw holes  5   c  on both sides of the opening  5   a , through which screws are inserted. Each of the grounding pieces  5   b  is formed with a screw hole  5   d  at a position corresponding to the screw hole  5   c.    
         [0024]    Further alternatively, the adapter  1  may be fabricated by setting the conductive plate  3 ,  4 ,  5 , when the conductive plate  3 ,  4 ,  5  is a metal, in a mold, and integrally molding the receptacles  2  on both sides of the conductive plate  3 ,  4 ,  5  by insert molding or the like.  
         [0025]    In the adapter  1 , means for fixing the adapter  1  to the panel is not limited to screws, as long as the conductive plate  3 ,  4 ,  5  can be grounded through the panel.  
         [0026]    Next, a second embodiment of the adapter according to the present invention will be described in detail with reference to FIGS. 4 through 6.  
         [0027]    As illustrated in FIG. 4, the adapter  10  is integrally formed by depositing two receptacles  11  or bonding them with an adhesive or the like. A housing  15  is attached to at least one of the receptacles  11 . In this event, optical connector plugs are inserted into the receptacles  11  of the adapter  10  from both sides thereof and connected with each other.  
         [0028]    The receptacle  11  comprises a prismatic body  11   a ; an opening  11   b  formed in a front portion of the body  11   a  for receiving a multifiber connector, for example, an MPO (Multifiber Push-On) connector or the like which is inserted through the receptacle  11 ; and flanges  11   c  formed in a rear portion of the body  11   b  and extending on both sides of the body  11   b . Each of the flanges  11   c  is formed with a screw hole  11   d  for fixation to a panel of a wiring board, not shown. Here, the panel of the wiring board is made of a conductive metal, and is grounded beforehand.  
         [0029]    The housing  15  is molded substantially in the same shape as the receptacle  11  using the same conductive material as the conductive plate  3 , and covers the receptacle  11 . The housing  15  comprises a prismatic body  15   a ; an opening  15   b  formed in a front portion of the body  15   a ; and flanges  15   c  extending on both sides in a rear portion of the body  15   a  and formed with screw holes  15   d . The opening  15   b  is sized such that a multifiber connector can be inserted therethrough. The opening  15   b , when excessively large, causes a reduced shielding effect for electromagnetic waves, and when excessively small, prevents a multifiber connector from being inserted therethrough.  
         [0030]    The adapter  10  is constructed as described above, and for example, when the two receptacles  11  have been previously fixed on a panel of a wiring board, the housing  15  is retrofitted to one receptacle  11 , as illustrated in FIG. 5. This causes the adapter  10  to sandwich the panel of the wiring board between the flange  11   c  of the one receptacle  11  and the flange  15   c , so that the housing  15  is grounded through the panel.  
         [0031]    Thus, even if the adapter  10  is connected to a multifiber connector connected to a high power optical module, the housing  15  shields strong electromagnetic waves. In this manner, the adapter  10  can remove electromagnetic influences simply and inexpensively.  
         [0032]    Alternatively, when the adapter  10  is newly mounted to the panel of the wiring board, the adapter  10  may be fixed to the panel by fitting the housing  15  on one receptacle  11 , inserting the other receptacle  11  into an opening (not shown) formed in the panel for mounting, and inserting screws through the screw holes  11   d ,  15   d  of the flanges  11   c ,  15   c  from the screw holes  15   d  of the housing  15 .  
         [0033]    Here, in the adapter  10 , means for fixing the adapter  10  to the panel is not limited to screws, as long as the housing  15  can be grounded through the panel.  
         [0034]    As illustrated in FIG. 6, when the housings  15  are attached to both receptacles  11 , the adapter  10  provides a further improved shielding effect for electromagnetic waves.  
         [0035]    While the foregoing embodiments have been described for an adapter for a multifiber connector which is an MPO connector, it should be understood that a multifiber connector connected to the adapter is not limited to the MPO connector. Also, the adapter of the present invention can be applied to an adapter for a single-fiber connector.  
         [0036]    Additionally, the adapter  10  may be manufactured by previously molding the two receptacles  11  integrally beforehand, other than integrally forming the two receptacles  11  by depositing them, or bonding them with an adhesive or the like, as in the foregoing embodiments.