Abstract:
An optical connector having alignment members for aligning with a connector on two mutually perpendicular axis with the optical connector including a displaceable block carrying optical fibers therein that is spatially positionable along a third axis to provide optical communication through the optical connector even though the optical connector may not have continuous optical fibers extending therethrough.

Description:
FIELD OF THE INVENTION 
   This invention relates in general to connectors and more specifically to optical connectors having a displaceable connector block that is axially displaceable to provide optical communication through one or more optical fibers carried by optical connector. 
   CROSS REFERENCE TO RELATED APPLICATIONS 
   None 
   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
   None 
   REFERENCE TO A MICROFICHE APPENDIX 
   None 
   BACKGROUND OF THE INVENTION 
   The use of optical fibers for connecting circuit boards and the like to other circuit boards or to other devices such as a backplane is known in the art. Typically, one end of a flexible optical cable is secured to the circuit board and another end having a connector is secured to the external device such as a backplane connector. These type of flexible connectors are referred to in the industry as “pigtail connectors”. While these type of flexible cable connectors provide an optical connection between the circuit board and the backplane they also require additional space in the compartment since the “pigtail connectors” have excess length, which forms a U-shaped loop in the flexible cable, that must be accommodated for by having extra space around the circuit board or the backplane connector. 
   While rigid optical connectors could be included on both the circuit board and the backplane connector such connectors would require extremely close tolerance to properly position the circuit board with respect to the backplane connector thus making such rigid connections unsuitable for most applications. 
   The present invention provides an optical connector that can be secured to a circuit board or the like with the optical connector including a displaceable connector block that allows one to connect the circuit board to the backplane connector without the need for precise three dimensional alignment between the circuit board and the backplane connector. As a result the present invention simplifies the manufacturing process while reducing the module area and the cost in providing optical connections between portions of a system such as a circuit board and a backplane. A further benefit is the optical connector of the present invention provides improved maintainability of the connection as well as improved reliability. 
   SUMMARY OF THE INVENTION 
   An optical connector having guide pins for aligning with a connector along two mutually perpendicular axis with the optical connector including a displaceable block carrying optical fibers therein that is spatially positionable along a third axis to provide optical communication across a gap in the optical connector. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a cutaway view of the optical connector of the present invention in the unmated condition; 
       FIG. 2  is a cutaway view of the optical connector of  FIG. 1  in a mated condition; 
       FIG. 3  is an end view of the optical connector of  FIG. 1 ; 
       FIG. 4  is a sectional view taken along lines  4 — 4  of  FIG. 2 ; 
       FIG. 5  is a plane view of a circuit board with an optical connector in an unmated condition with a receptacle on a backplane connector; 
       FIG. 6  is a plane view of a circuit board with an optical connector of  FIG. 5  in a mated condition with a receptacle on a backplane connector; and 
       FIG. 7  is a cut away of the receptacle and the optical connector illustrating the face contact between the optical connector and the receptacle. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1  is a cutaway view of an optical connector  10  in an unmated condition. Optical connector  10  comprises a base  11  for securing to optical connections on a circuit board or the like, a flange  12  and a shroud  13 . A first guide pin  15  extends from flange  12  through one side of a displaceable connector block  14  and a second guide pin  16  extends from flange  12  through the other side of displaceable connector block  14 . Displaceable connector block  14  is slideable along guide pins  15  and  16 . A first compression spring  19  located around guide pin  15  coacts with a second compression spring  18 , which is located around guide pin  16  to provide a separation force to resiliently maintain block  14  in a spaced condition from a lens array in face  11   a  of base  11  as illustrated in FIG.  1 . The lens array located in face  11   a  includes a set of optical fibers  20   a ,  21   a  and  22   a  with respective micro lenses  20 ,  21  and  22 , that are directed toward a corresponding set of lenses  14   m ,  14   n  and  14   o  that respectively connect to optical fibers  14   x ,  14   y  and  14   z  in displaceable block  14 . The micro lenses  20 ,  21  and  22  respectively convert the light from the fibers  20 ,  21   a  and  22   a  into collimated free space optical transmissions that are received respectively by lenses  14   m    14   n  and  14   o.    
     FIG. 2  is a cutaway view of the optical connector  10  as it would appear with displaceable block  14  in the mated condition. In a mated or optical transmission condition the displaceable block  14  slides toward face  11   a  with the flange  14   a  on block  14  slidingly engaging the interior of shroud  13 . That is, block  14  is axially sliding along guide pins  15  and  16 . The purpose of guide pins  15  and  16  are two fold. First, they maintain block  14  and the set of optical fibers  14   x ,  14   y  and  14   z  in block  14  in optical alignment with the optical lenses  20 ,  21 , and  22  in face  11   a . Second, the guide pins  15  and  16  comprise alignment members to provide two dimensional location of the connector  10  with respect to an attachment device. Consequently, only two-dimensional positioning is needed to mate the optical connector  14  with an external connector  35 . Alignment in the third dimension is rendered less critical as block  14  can be displaced along guide pins  15  and  16  to accommodate alignment in the third mutual perpendicular axis. That is, the optical free transmissions from the connector face  11   a  are maintained in optical alignment with the corresponding lenses  14   m ,  14   n  and  14   o  fibers in block  14  allowing optical signals to traverse a gap between the face  11   a  and the face  14   b  of block  14 . 
     FIG. 3  is an end view of the optical connector  10  showing the displaceable block  14  confined by shroud  13 . Shroud  13  prevents interference with optical connections therethrough by preventing objects or external optical signals from contaminating the optical path in the gap between face  11   a  and face  14   b . Located between the guide pins  15  and  16  are optical lenses  14   m ,  14   n  and  14   o . Block  14  includes a cylindrical surface  15   a  that slidingly engage pin  15  and a cylindrical surface  16   a  that slidingly engages pin  16 . 
     FIG. 4  is a sectional view taken along lines  4 — 4  of  FIG. 2  showing the face  14   b  of block  14  with the optical fibers  20   a ,  21   a  and  22   a  each having a lens visible in face  14   b . A reference to  FIG. 2  shows dotted lines projecting from optical lenses  20 ,  21 , and  22  to optical lenses  14   m ,  14   n  and  14   o  which are included to indicate that an optical signal from optical fiber  20   a  is in optical communication with optical fiber  14   x  across an open gap and that optical fiber  21   a  is in optical communication with optical fiber  14   y  across an open gap and the optical fiber  22   a  is in optical communication with optical fiber  14   z  across an open gap. 
     FIG. 5  is a plane view of a circuit board  30  with an optical connector  10  in an unmated condition with respect to a backplane receptacle  35  on a backplane  31 . 
     FIG. 6  is a plane view of a circuit board  30  with an optical connector  10  of  FIG. 5  in a mated condition with a backplane connector  35 . Circuit board  30  connects externally through base  11  and optical connector  10 . In operation it is desired to form an optical connection from circuit board  30  to backplane connector  35  which is mounted in back backplane  31 . An optical cable  36  provides for optical connection to another portion of the system. In the embodiment shown in  FIG. 5  it is noted that the optical connector  10  and circuit board  30  are in a spaced or unmated condition from backplane connector  35  while in  FIG. 6  the optical connector  10  is in a mated condition or in optical connection with backplane connector  35 . 
   A retention mechanism can also be a part of connector  35  or  10  such as locking levers, latches or other retentions members such as wedge locks. (not shown) 
   The mated condition of optical connector  10  is more fully illustrated in  FIG. 2  which shows the shroud  13  partially cutaway to reveal the parallel optical paths between the block  14  and the receptacle  35 . This optical connection is present regardless of the position of the block within optical connector  10 . 
   In order to reveal how the optical communication is formed between optical receptacle  35  and block  14 , reference should be made to  FIG. 7 , which shows a partial sectional view of a portion of block  14  and receptacle  35 .  FIG. 7  shows that guide pin  15  extends into socket  35   a  and guide pin  16  extends into socket  35   b  in receptacle  35  to provide two-dimensional alignment of receptacle  35  with block  14 . In the condition shown an external face on block  14  comprising a contact face  14   b  is in contact with an external face also comprising a contact face  35   c  of receptacle  35 . In this condition optical fiber  14   m  is in optical communication with optical fiber  20   b . Similarly, optical fiber  14   n  is in optical communication with optical fiber  21   b  and optical fiber  14   o  is in optical communication with optical fiber  22   b . Thus in this embodiment the connector  35  and block  14  are in face-to-face contact to provide a continuous optical signal path through the connector to the receptacle  35 . The use of springs  18  and  19  permit the connector  10  and receptacle to be brought into pressure contact with each other and to be maintained in pressure contact thereby ensuring that the face to face contact between contact face  14   b  and external face  35   c  is maintained during use of the optical connectors. 
   A further aspect of the invention is the method of making an optical connection between a first device and a second device comprising the steps of mounting a connector or receptacle  35  on the second device such as a backplane  31  and mounting an optical connector  10  on the first device, such as a circuit board  30  with the optical connector having two dimensional alignment members such as pins  15  and  16 . By placing each of the alignment members  15  and  16  in a socket in the receptacle  35  one can provide two dimensional alignment of the optical connector  10  and the receptacle  35  and by continuing to bring the optical connector  10  toward the receptacle  35  until an external face  14   b  of the optical connector and an external face  35   b  of the receptacle are in contact and then by maintaining the optical connector and receptacle in position one can form an optical connection between the receptacle  35  and a displaceable block  14  in the optical connector  10 .