Abstract:
Optical transceiver modules which may be attached to printed circuit boards or other planar supports are presented. The optical transceiver module includes a housing mountable on a board such that a first portion of the housing is above a plane of the board and a second portion of the housing is below the plane of the board. The board may be any planar support, including a circuit board. The plane may be any plane in the board such as a center plane, for example.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to an optical transceiver housing that mounts and secures to a circuit board and in particular, an optical transceiver housing that efficiently utilizes the available space. 
   2. Discussion of Related Art 
   Optical transmission of data is a common method used for telecommunications and data communications. A fiber optic cable is capable of transmitting several wavelengths of light which can carry different channels for different data simultaneously. Optical transceivers translate this optical data from a fiber optic cable into an electrical signal, and vice versa, translating electrical signals into optical data. 
   Typically, an optical transceiver would be mounted onto one surface of a circuit board. This circuit board is commonly one of many circuit boards mounted in a rack stiffener assembly connected to a backplane and anteriorly secured with a face plate. The clearance between circuit boards is usually small. As optical transceiver technology evolves, more hardware is placed in the optical transceiver module to provide greater functionality. This in turn creates an optical transceiver with a greater size. Unfortunately, the clearance space between circuit boards remains small. Therefore, there is a need for optical transceivers that optimally utilize available space. 
   SUMMARY 
   Optical transceiver modules which may be attached to printed circuit boards or other planar supports are presented. 
   In some embodiments, an optical transceiver module includes a housing mountable on a board such that a first portion of the housing is above a plane of the board and a second portion of the housing is below the plane of the board. The board may be any planar support, including a circuit board. The plane may be any plane in the board such as a center plane, for example. 
   In some embodiments, an optical transceiver module includes at least a part of a notch and rail system. The notch may be provided by the housing and the rail provided by the board. The inverse is also possible, where the notch may be provided by the board and the rail provided by the housing. The housing slides onto the board via the notch and rail system. In some embodiments, the notch and rail system is adjustable in height. This can be accomplished, for example, using a rack and pinion system. In one implementation the rack is located on a lateral wall of the notch and the pinion impinges upon the rack. When the pinion is turned the rack moves, thereby changing the width of the notch. 
   In some embodiments, the housing is in a shape of wedge. The wedge shape aids in guiding and securing the optical transceiver module into the board. 
   In some embodiments, the housing includes a securing mechanism at an interfacing surface of the housing with the board to hold the housing in place against the board. In some implementations, the securing mechanism is a spring clip. Tension provided by the spring clip holds the housing against the board. 
   In some embodiments, the housing includes at least one attaching mechanism located posteriorly to hold the housing in place in a cut out of the board. In one embodiment, the attaching mechanism includes at least part of a notch and rail system. In another embodiment, the attaching mechanism includes a latch arm that secures to the board through a hole in the board. In another embodiment, the attaching mechanism includes a screw that screws into a threaded piece attached to the board. 
   In some embodiments of the invention, the housing includes a heat sink coupled to an exposed surface. The heat sink is made of a heat conductive material and may include heat fins. 
   An optical transceiver module which can be mounted through the center plane of a circuit board or other planar support allows the optical transceiver module to better reside in a rack stiffener assembly which has limited clearance between circuit boards. In particular, such a transceiver module can be larger than conventional transceiver modules and thus accommodate more functionality and still fit into the space between boards. 
   These and other embodiments of the invention are further discussed below with respect to the following figures. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1A  is a perspective view of an embodiment of an optical transceiver housing coupled to an electrical connector. 
       FIG. 1B  is a block diagram of an optical transceiver that may be mounted in a housing according to the various embodiments. 
       FIG. 1C  is a perspective, partially transparent view of an embodiment of an optical transceiver housing. 
       FIG. 1D  is a perspective view of an optical transceiver housing as shown in  FIG. 1C  mounted onto a board. 
       FIG. 1E  is a perspective view of another embodiment of an optical transceiver housing coupled to an electrical connector. 
       FIG. 2  is a perspective, partially transparent view of an embodiment of an optical transceiver housing that provides part of an adjustable notch and rail system. 
       FIG. 3  is a lateral view of an embodiment of an optical transceiver housing that may be secured to a board using a posterior notch. 
       FIG. 4  is a lateral view of an embodiment of an optical transceiver housing that may be secured to a board using an adjustable posterior notch. 
       FIG. 5A  is a lateral view of an embodiment of an optical transceiver housing that includes a securing mechanism. 
       FIG. 5B  a top view of a board to which the embodiment of  FIG. 5A  may be attached 
       FIG. 5C  is a lateral view of another embodiment of an optical transceiver housing that includes a securing mechanism. 
       FIG. 6  is a top view of another embodiment of an optical transceiver housing attached to a board. 
       FIG. 7  is a perspective view of the optical transceiver housing depicted in  FIG. 6  mounted on a board. 
       FIG. 8A  is a lateral view of a securing mechanism in one embodiment. 
       FIG. 8B  is a top view of the securing mechanism depicted in FIG.  8 A. 
       FIG. 9  is a lateral view of an embodiment of an optical transceiver housing that includes heat fins. 
       FIG. 10  is a perspective view of the optical transceiver housing of  FIG. 9  partially inserted in a chassis. 
   

   It should be noted that the dimensions in the figures are not necessarily to scale. Like reference numbers in the various figures denote like parts in the various embodiments. 
   DETAILED DESCRIPTION 
     FIG. 1A  shows an embodiment of an optical transceiver housing  100  mounted on a board  115 . This particular embodiment shows the conventional input and output of an optical transceiver with fiber optic  111  input through anterior side  101  of housing  100 . In addition, electrical output from the optical transceiver occurs through transceiver mounted plug  112  which docks onto board mounted plug  113  on posterior side  102  of housing  100 . 
   In some embodiments, the bottom surface of transceiver mounted plug  112  electrically interfaces with the top surface of board mounted plug  113 . One skilled in the art will recognize a number of connectors for coupling electrical signals from housing  100  to circuitry on or in board  115 . The electrical output signals exit board mounted plug  113  through electrical leads  114 , which can be coupled to electrical conductors on board  115 . 
     FIG. 1B  shows a block diagram of an embodiment of an optical transceiver. Optical fiber  111  provides optical data signals to or receives optical data signals from the optical transceiver&#39;s detector/source  116 . When receiving data signals from fiber optic cable  111  the detector/source  116  is a detector of the light emitted from fiber optic cable  111 . The optical data input signals are translated into electrical data which are then transmitted electrically to the transceiver&#39;s driver  117 . Driver  117  drives the electrical data signals through the electrical output conductors  118 . As a transmitter, electrical data signals are provided through electrical conductors  118  to driver  117 . Driver  117  drives optical source  116  to emit optical signals which are coupled into optical fiber  11 . The data signals exit the optical transceiver through fiber optic cable  111 . Detector/source  116 , driver  117 , and other components of an optical transceiver may be housed in embodiments of optical transceiver housing  100  disclosed herein. 
     FIG. 1E  shows another embodiment similar to that of FIG.  1 A. In this embodiment a circuit board  121  posteriorly extends from housing  100  into a card edge connector  113  mounted on board  15 . Electrical output signals from the optical transceiver are conducted through circuit board  121  which docks into card edge connector board mounted plug  113 . As in  FIG. 1A , electric output signals exit card edge connector board mounted plug  113  through electrical leads  114  which can be connected to conductors on board  15 . 
     FIGS. 1C and 1D  show an optical transceiver housing  100  according to some embodiments of the present invention. In these embodiments, optical transceiver housing  100  includes part of a notch and rail system  110  comprising one or more notches  104  and a one or more rails  106 . Notches  104  reside on the lateral sides of the optical transceiver housing. Rails  106  are provided by lateral edges  108  of a cutout portion of board  115 . In the illustrated embodiment, notches  104  allow optical transceiver housing  100  to slide onto board  115  using edges  108  of the board as rails  106 . As shown in  FIG. 1D , optical transceiver housing  100  slidably mounts onto board  115  and has an upper portion  120  above a plane  119  of board  115  and a lower portion  130  below plane  19  of board  115 . Plane  119  is a plane located anywhere within board  115 . 
   Notch and rail system  10  may be implemented in other ways, as well. For example, housing  100  could provide a rail similar to rail  106  that would fit into a notch provided by board  115  similar to notch  104 . In another example, pins that fit in notch  104  replace rail  106  to provide similar supporting and guiding functions. In another embodiment, the notch and rail system does not run the full length or width of housing  100 . 
     FIG. 2  shows an embodiment in which notch and rail system  10  is adjustable by a rack and pinion system  200 . In this embodiment, housing  100  includes a sub housing  100 A with a T-shaped cross-section and a sub-housing  100 B with a U-shaped cross-section. Sub-housing  100 A includes a tongue  152  that fits vertically into a groove  154  defined by sub-housing  100 B. Rack and pinion system  200  controls the depth at which sub-housing  100 A is inserted into sub-housing  100 B, thereby adjusting the height of notch  104  formed between two opposing surfaces of sub-housings  100 A and  100 B. Rack and pinion system  200  includes a rack  210  formed on a lateral surface of sub housing  100 A and a pinion gear  220  rotatably mounted to sub-housing  100 B and engaged to rack  210 . When pinion gear  220  is turned against rack  210 , sub-housing  100 A is moved relative to sub-housing  100 B to adjust the height of notch  104 . The rack and pinion system  200  in this embodiment allows notch  104  to adjust for a thicker or thinner rail  106   FIG. 1C ) provided by any size board. Alternatively, a similar adjustable notch system can be attached to board  115  to accommodate any size rail provided by optical transceiver housing  100 . Such a notch system may include adjustable clamps fixed to a board providing notches that can engage rails provided by an embodiment of housing  100  (not shown). Another alternative (not shown) may provide a rack and pinion system similar to rack and pinion system  200  attached to a board which provides an adjustable shelf on which optical transceiver housing  100  may rest, with an upper portion  120  and a lower portion  130  extending from board  115 . 
     FIG. 3  shows a lateral view of optical transceiver housing  100  according to another embodiment. In this embodiment, housing  100  may be attached at its posterior side  102  to a board such as board  115  shown in FIGS.  1 A and  1 C- 1 E.  FIG. 3  shows a notch  104  on the posterior side of housing  100  that may secure housing  100  to a rail provided, for example, by an edge of the board.  FIG. 3  also shows anterior side  101  of housing  100  attached by screws  310  to a face plate  300  of a chassis, for example, in which the board is mounted. Optical transceiver housing  100  may include a flange  160  as shown in FIG.  3 . In such embodiments, optical transceiver housing  100  may be inserted through an opening in face plate  300  and positioned such that flange  160  is flush with face plate  300 . Screws  310  may then be passed through holes in flange  160  to attach housing  100  to face plate  300 . 
     FIG. 4  shows another embodiment similar to that of FIG.  3 . In this embodiment, rack and pinion system  200  may be used to adjust the height of a notch on the posterior side  102  of housing  100 . This notch may be used to secure housing  100  to a rail provided, for example, by the edge of a circuit board. As in the embodiment illustrated in  FIG. 3 , anterior side  101  of housing  100  may be attached to a face plate  300  with, for example, screws  310  and  400 . In this embodiment, screw  400  may be coupled to pinion gear  200  so that the height of the notch in posterior side  102  of housing  100  may be adjusted by turning screw  400 . Alternatively, a rack and pinion system located on a board to which housing  100  is to be mounted may be operated by screw  400 . In such embodiments, screw  400  may be operated to adjust the height of a notch provided by the board and located to engage a rail provided on posterior side  102  of housing  100 . 
     FIGS. 5A ,  5 B, and  5 C illustrate other embodiments that allow optical transceiver housing  100  to be attached posteriorly to a board.  FIGS. 5A and 5B  show a particular embodiment that is similar to the embodiment described in  FIG. 4 , except screw  400  is coupled to a latch arm  500  which can be rotated through a hole  510  in board  115  (see  FIG. 5B ) to lock housing  100  to board  115 . Other mechanisms controlled by screw system  400  can be used to achieve the same function, such as that shown by FIG.  5 C.  FIG. 5C  shows an embodiment in which screw  400  has a threaded end  512  that passes through housing  100  and screws into a threaded piece  511  attached to board  115 , thereby securing housing  100  to board  115 . 
   In other embodiments an optical transceiver housing  100  may include combinations of the features described above. For example, an embodiment can include a lateral notch and rail system ( FIG. 1C , for example) in addition to a posterior notch and rail system ( FIG. 3 , for example). Either or both notch and rail systems may be adjustable by rack and pinion systems ( FIGS. 2 and 4 , for example). 
     FIGS. 6 and 7  show an embodiment in which optical transceiver housing  100  has a wedge shape.  FIG. 6  is a top view of the housing  100  mounted on a board  115 . The wedge shape can aid in guiding the optical transceiver onto board  115  and provide optimal docking of a transceiver to electrical leads on board  115 . Such embodiments may be similar to the embodiments describe above, for example, but for the wedge shape of housing  100 . 
   In the embodiment shown in  FIGS. 8A and 8B , a securing mechanism  800  is located in notch  104  of optical transceiver housing  100 .  FIGS. 8A and 8B  show, respectively, side and top views in which securing mechanism  800  is implemented as a spring clip. Securing mechanism  800  provides tension at the interface between notch  104  of optical transceiver housing  100  and rail  106  of board  115 . Any number of mechanisms  800  may be attached to either housing  100  or board  115 . In other embodiments a securing mechanism  800  may include a spring covered by a button embedded in either interfacing surface (housing  100  or board  115 ). 
     FIG. 9  is a lateral view of another embodiment of housing  100 . In this embodiment, housing  100  includes heat fins  900  that can be used to dissipate heat generated by the optical transceiver. Heat fins  900  can be located on the top surface of housing  100  (as shown), the bottom surface of housing  100  (not shown), or both top and bottom surfaces (not shown). Also shown in this particular embodiment are screws  310  used to anteriorly secure the optical transceiver housing  100  to face plate  300  of a chassis  320  in which board  115  is mounted. Housing  100  is laterally secured to board  115  using notch and rail system  110 . Upper portion  120  of housing  100  is positioned above a plane of board  115 . Lower portion  130  of housing  100  is positioned below the plane of board  115 . 
     FIG. 10  is a perspective view showing the optical transceiver housing  100  of  FIG. 9  partially inserted into a chassis  320  in which board  115  is mounted. Notch  104  on housing  100  has engaged rails  106  formed by the edge of a cut out portion of board  115 . In this embodiment, optical transceiver housing  100  (and the transceiver it contains) may be installed in chassis  320  by sliding transceiver housing  100  along board  115  until flange  160  is flush with face plate  300  and circuit board  121  extending from optical transceiver housing  100  (visible in  FIG. 9 ) docks with card edge connector  113 . Screws  310 , which pass through flange  160  of optical transceiver housing  100 , may then be tightened to engage threads in tapped holes  315  of face plate  300 . Optical fibers may be coupled to a transceiver in transceiver housing  100  using, for example, conventional fiber optic receptacles  325 . 
   The particular embodiments discussed above are illustrative only and are not intended to be limiting. One skilled in the art will recognize various alternatives which are intended to be within the spirit and scope of this disclosure. As such, the invention is limited only by the following claims.