Abstract:
An AOC assembly comprising two printed circuit boards (PCB) ( 63 ), a board holder ( 61 ) and two heat conducting covers ( 64 ) with integrated head spreader. Each of the two PC boards has a lower edge ( 632 ) extending in a longitudinal direction with circuit pads on opposite sides of PCB thereof. The board holder has two opposite vertical datum faces with two of said PC boards respectively positioned thereon. The two heat conducting covers oppositely fixed to the holder in a transverse direction perpendicular to the PC boards. When assembled, the integrated heat spreader of heat conducting shell would dissipate heat from the active electronic components on the PCB.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This patent application is related to a pending U.S. patent application Ser. No. 13/858,932, filed on Apr. 8, 2013, and entitled “OPTO-ELECTRONIC DEVICE ASSEMBLY”, which is assigned to the same assignee with this application. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to opto-electronic (OE) device assemblies, and more specifically to integrating multiple OE modules with waveguide, e.g., Fiber or Polymer Waveguide (PWG), as an OE sub-assembly to further reduce user&#39;s installation and testing costs. 
     2. Description of Related Art 
     Most computer and communication networks today rely on copper wire to transmit data between nodes in the network. Since the data transmitted over the copper wire and the data processed within the nodes are both represented in the form of electrical signals, the transfer of data at the node-copper wire interface is straight forward. Other than perhaps level shifts and signal amplification, no other signal processing is required for data transmitted over the copper wire to be decoded by the node. The drawback with using copper wire is its relatively narrower bandwidth. Copper&#39;s ability to transmit data is significantly limited compared to other mediums, such as fiber optics. Accordingly much of the computer and communication networks built today, including the Internet, are using fiber optic cable instead of copper wire. 
     With fiber optic cable, data is transmitted using light wave, rather than electrical signals. For example, a logical one (1) may be represented by a light pulse of a specific duration and a logical zero (0) may be represented by the absence of a light pulse for the same duration. In addition, it is also possible to transmit at the same time multiple colors of light over a single strand of optic fiber, with each color of light representing a distinct data stream. Since light is attenuated less in fiber than electrons traveling through copper, and multiple data streams can be transmitted at one time, the bandwidth of optic fiber is significantly greater than copper. 
     While fiber optic data transmission has proven very efficient, substantial problems have been encountered when applying these light signals to process data. Transferred data is typically stored in various locations before, during and after it is processed by a computer. Since there is currently no efficient technique to “store” these light packets of data, networks will likely continue to use fiber optics for transmitting data between nodes and silicon chips to process the data within the nodes for the foreseeable future. Building such networks requires opto-electronic transceivers, which connect optical transmission devices to electronic computing devices through devices that transform optical signals to electronic signals, and vice-versa. 
     Ideally, such opto-electronic transceivers should provide secured and reliable connections between the various devices and should be compact in size. Secured connections ensure that the individual devices do not disconnect and therefore cause a failure in the opto-electronic transformation process. Compactly sized transceiver modules allow a higher density of optical cables to be attached to an electronic printed circuit board, thereby increasing the bandwidth available to the computing system. 
     While the transceiver design adequately ensures a secure connection between optical and electronic devices, assembly of its individual sub-assemblies is mechanically complex. 
     In view of the foregoing, a simple and compact opto-electronic transceiver capable of providing secure connections between optical and electronic devices would be desirable. Specifically, this instant invention is to replace the current ceramic substrate which is implanted with 56 Duece modules thereon. 
     SUMMARY OF THE INVENTION 
     Accordingly, an object of the present invention is to provide a new modular active optical interconnect system for replacing the traditional ceramic substrate implanted with a plurality of OE modules. The modular active optical interconnect system includes a simple and compact flat-top heat conducting shell to receive water-cooling manifold and a plastic molded PCB holder having enhance features in contacts that will improve the overall cooling efficiency in the system. 
     In brief, technically speaking the prior art is to install a plurality of OE module in a LGA socket which is for electrical interface. After the OE module converting the electrical signal into optical signal and vice versa, an optical connector with waveguide is to attach to the optical interface of OE module for optical signal transmission or receiving. Due to the active components of OE module which generates heat, a heat sink/spreader is required for heat dissipation. In the field, it is troublesome to install all those components, inspection, testing and field service. The invention is to put all those troublesome behind by organizing all those components in an Active Optical Cable (AOC) package. The user just plugs in the AOC into socket or unplug just like an ordinary cable assembly. An organizer is to allow a plurality of AOC to align with the socket to form a compact package in a dense area. It makes easy installation and field serviceable. 
     A preferred advantage of the present invention is to provide an AOC plug comprising one or more PC boards each equipped with OE components and having a lower edge extending in a longitudinal direction with circuit pads on opposite side thereof; a board holder having two opposite vertical datum faces with two of said PC boards respectively positioned thereon; two heat conducting covers oppositely fixed to said holder in a transverse direction perpendicular to the PC boards. The integrated heat spreader of heat conducting shell would dissipate heat from the active electronic components on the PCB after assembly. 
     Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a top view showing the substrate of the present preferred embodiment of the instant invention wherein one side of the connectors are removed to show the area is same as that arranged for the conventional 4×7 OE module socket of the prior art. 
         FIG. 2  is a perspective view of a frame with therein the substrate of the  FIG. 1  while without the organizer and the connectors attached to the ceramic substrate. 
         FIG. 3  is a top view of the substrate of  FIG. 1  without the organizer and the connectors attached thereto. 
         FIG. 4  is a partial perspective view of  FIG. 2  to show how the organizer is ready to be assembled to the base. 
         FIG. 5  is a partial perspective view of  FIG. 4  to show the organizer is assembled to the base so as to have the associated connectors electrically and mechanically connected to the ceramic substrate. 
         FIG. 6  is a top view to show the organizer with the connectors therein. 
         FIG. 7  is a perspective view to show the organizer with the connectors therein. 
         FIG. 8  is an upside down perspective view to show the assembling direction of the connector with regard to the organizer. 
         FIG. 9  is a top view of the connector to show two receiving slots therein. 
         FIG. 10  is an enlarged partial view of  FIG. 9  to show the staggered arrangement of the contacts by two sides of the corresponding receiving slot. 
         FIG. 11  is a perspective view of the connector. 
         FIG. 12  is an illustrative elevational view to show the LGA type and paddle card type contact interfaces. 
         FIG. 13  is a perspective view to show the AOC module. 
         FIG. 14  is a top view to show the AOC module. 
         FIG. 15  is another perspective view to show the AOC module of  FIG. 13 . 
         FIG. 16  is a partially exploded view of the AOC module of  FIG. 13 . 
         FIG. 17  is another partially exploded view of the AOC module of  FIG. 13 . 
         FIG. 18  is another partially exploded view of the AOC module of  FIG. 13 . 
         FIG. 19  is a partially exploded view of AOC module of  FIG. 13  with two heat conducting covers and a board holder removed. 
         FIG. 20  is a side view the AOC module of  FIG. 13  with one heat conducting cover and one PC board removed. 
         FIG. 21  is a cross section view of the AOC module of  FIG. 20  taken alone the line  21 - 21 . 
         FIG. 22  is a cross section view of the AOC module of  FIG. 20  taken alone the line  22 - 22 . 
         FIG. 23  is a cross section view of the AOC module of  FIG. 20  taken alone the line  23 - 23 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Reference will now be made in detail to the preferred embodiment of the present invention. 
     Referring  FIGS. 1-23 , an aluminum frame  10  defines a ceramic substrate receiving area to receive a ceramic substrate  12  therein. The ceramic substrate  12  defines two connector areas  14 , on two opposite ends in a longitudinal direction, forming LGA (Land Grid Array) pads  16  thereon. A modular SLC (Surface Laminate Circuit) interconnect system  18  is fastened to the aluminum frame  10  around each of the connector areas  14 , and includes an aluminum organizer  20  defining a plurality of elongated cavities  22  in a transverse direction perpendicular to the longitudinal direction while each of the cavities  22  extends along the longitudinal direction. The aluminum organizer  20  defines a plurality of fastening holes  24  and a plurality of locating holes  26  to receive corresponding screws  28  and dowel pins  30  for locating and fastening the organizer  20  upon the aluminum frame  10 . The organizer  20  further includes a pair of tower structures  32  on two lateral sides in the transverse direction to commonly defines plural pairs of vertical guide channels  34 . A plurality of card edge connectors (receptacle)  36  are respectively disposed in the corresponding cavities  22 . The cavity  22  is configured to allow the connector  36  to be assembled thereinto in only an upper direction. 
     Each connector  36  includes an insulative housing  38  defines a pair of card receiving slots  40  in the transverse direction while each card receiving slot  40  extends along the longitudinal direction. A plurality of passageways  42  are formed in the housing  38  and by two sides of the corresponding card receiving slot  40  in a staggered manner along the transverse direction. A plurality of contacts  44  are disposed in the corresponding passageways  42 , respectively. Each contact  44  includes an upper contacting section  46  extending into the corresponding card receiving slot  40 , a middle retaining section  48  retained to the housing  38 , and a lower tail section  50  for contacting the corresponding LGA pad  16  wherein in a side view the upper contacting sections  46  of the contacts  44  which share the same card receiving slot  40 , are symmetrically arranged with each other while the lower tail sections  50  of the contacts  44  sharing the same card receiving slot  40  are arranged same with each other but commonly symmetrically arranged with the lower tail sections of the contacts sharing the other card receiving slot  40 . It is noted that the distance or pitch between the pair of card receiving slots  40  is 3.0 mm for compliance with the traditional SLC to SLC arrangement, and the pitch between the adjacent two contacts on the same side is 0.6 mm. 
     A plurality of SLC or AOC modules  60  (AOC plug) are assembled to the organizer  20  and the associated connectors  36 , respectively. Each SLC module  60  includes two opposite SLC or AOC assemblies  62 , an insulating board holder  61  sandwiched by the opposite AOC assemblies  62  and a pair of heat conducting covers  64  closed to receiving the AOC assemblies  62 , and an optical cable assembly  66 . 
     Each of the SLC or AOC assemblies  62  comprises an SLC board  63  capable of transmission of twelve pairs Tx and twelve pairs Rx with 0.6 mm pitch thereof and equipped with a micro-controller, two OE glass lenses, a Tx IC chip, a Rx IC chip, a plurality of VCSEL and PD arrays (VCSEL and PD could be named OE components). The plurality of VCSEL and PD arrays are respectively coupled to the optical cable assembly  66  by the two OE glass lenses. Each of SLC boards  63  has a lower edge  632  extending in a longitudinal direction with circuit pads  636  on opposite side thereof. 
     The board holder  61  has a longitudinally extending bottom wall  610 , two end walls  612  extending downwardly to connect to longitudinal ends of the bottom wall  610 , two inner walls  614  protruding toward each other from inner sides of the two end walls  612  in the longitudinal direction, two longitudinal blocks  616  bumping out from outer sides of the two end walls  614  and an intermediate protrusion  611  upwardly extending from the bottom wall  610 . The intermediate protrusion  611  has a scaled portion  615  jointly with the two inner walls  614  defining two opposite vertical datum faces with said SLC boards  63  respectively positioned thereon. The scaled portion  615  is spaced from the bottom wall  610  with a pair of cutaway  613  defined therebetween. The bottom wall  610  defines two long and narrow passageways  617  for receiving the SLC boards  63  respectively. When assembled, the intermediate protrusion  611  and the two inner walls  614  are sandwiched by the two SLC boards  63 , the SLC boards  63  are longitudinally positioned between the two end walls  612  with the lower edges  632  extending downwardly through the long and narrow passageways  617 . 
     The pair of heat conducting covers  64  are screwed to each other with the board holder  61  and the two SLC boards  63  sandwiched therebetween in a transverse direction perpendicular to the SLC boards  63 . The heat conducting covers  64  have horizontal top walls  642  extending toward each other and overlapped with each other in the vertical direction. A first one of the two heat conducting covers  64  defines a first slope  646  guiding the second one downwardly and a second slope  648  guiding the second one upwardly when the two heat conducting covers  64  are transversely approaching to each other. The two heat conducting covers  64  could also be hinged to each other, which is shown in  FIG. 16 . Each of the two heat conducting covers  64  forms two protrusions  644  and two standoffs  640 . The two protrusions  644  of each heat conducting covers  64  extend into two through holes  630  defined in a corresponding SLC boards  63  around which high power components  638  (shown in  FIG. 22 ) are mounted. The standoffs  640  of the heat conducting covers  64  extending through concaves  634  defined in corresponding SLC PCB  63  and are supported by the inner walls  614  of the board holder  61 . A threaded bolt  652  extends through a through hole  643  defined in one standoffs  640  of the first heat conducting covers  64  and a through hole  619  defined in one inner walls  614  of the board holder  61  and then is screwed into a threaded hole  641  defined in one standoffs  640  of the second heat conducting cover  64 . A second threaded bolt  652  extends through a through hole  643  defined in the other standoffs  640  of the second heat conducting covers  64  and a through hole  619  defined in the other inner walls  614  of the board holder  61  and then is screwed into a threaded hole  641  defined in the other standoffs  640  of the first heat conducting cover  64 . 
     The optical cable assembly  66  has four sets of optical cables  660 , a strain-relief cable holder  662  holding the four sets of optical cables  660  and four molded lens mechanism  68  each positioning and coupling one set of optical cables  660  to one of the OE glass lenses of the two AOC assemblies  62 . The strain-relief cable holder  662  is secured in a slot  618  defined in one of the end walls  612  of the board holder  662 . 
     When assembled, for each SLC module  60 , the optical cable assembly  66  is assembled to the two corresponding SLC boards  63 . The SLC boards  63  is inserted into the corresponding card received slots  40  at the bottom after assembled to the heat conducting covers  64  and the board holder  63  via mounting screws  652 ,  654 . The board holder  63  is assembled to the organizer  20  via engagement between the bumping blocks  616  of the board holder  63  and guide channels  34  of the organizer  20 . 
     It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.