EP0852414B1

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Info

Publication number: EP0852414B1
Application number: EP97122940A
Authority: EP
Inventors: Bernardus L. Paagman
Original assignee: Berg Electronics Manufacturing BV
Current assignee: FCI SA
Priority date: 1997-01-07
Filing date: 1997-12-29
Publication date: 2004-11-24
Anticipated expiration: 2017-12-29
Also published as: JP4565673B2; CA2225151C; TW385579B; CN1190807A; EP0852414A3; DE69731719T2; JPH10270133A; CA2225151A1; DE69731719D1; SG71746A1; EP0852414A2

Description

The present invention relates to an electricalconnector as defined in the preamble ofclaim 1. The present invention relatesspecifically to high speed, shielded connectors having oneor more integrated PCB assemblies.
Connectors, havinginsulative bodies and individual metal terminals are now widely used andavailable in many different configurations. For most connector structuresthe usual method of manufacture comprises stitching or insert moldingterminals into a suitable housing. The manufacturing process may alsoinclude a terminal tail bending operation, especially for right angleconnectors. Connectors for high-frequency applications presentadditional requirements. In this regard, controlled-impedance terminalsections with ground shielding options are preferred. Towards this end, itis known to subdivide the manufacture of such a connector into one partfor accommodating contact terminals for mating contact with the contactterminal of a mating connector and a separate part for the tail end.Separate shielding casings, if required in a right angled configuration,may be provided around each of the terminals within the connector.Although connectors manufactured as described above operatesatisfactorily, the manufacturing costs are high.
U.S. Patent No. 4,571,014 shows a different approach for makingbackplane connectors using one or more PCB assemblies. Each of thePCB assemblies comprises one insulated substrate, one spacer, and onecover plate, all of which are attached to one another. The insulatingsubstrate is provided with a predetermined pattern of conducting tracks,while ground tracks are provided between the conducting tracks. Theconducting tracks are connected at one end to a female contact terminaland at the other end to a male contact terminal. Each of the cover platesis a conductive shield member.
In the arrangement according to U.S. Patent No. 4,571,014, thecircuit substrates are arranged with the sides bearing the conductivetracks all facing in the same direction. The cover plates/shields are eachinterleaved between adjacent substrates. While such an arrangementproduces a plurality of individual shielded tracks, it does not present thepossibility for creating impedance matched pairs of conductive tracksthrough the connector, in a twinax configuration. Twinax connectors areoften utilized in combination with twisted pair cable. Such twisted paircables usually have a plurality of pairs of identical conductors twistedalong the signal transmission length. Such a conductor pair has thesignal over the two conductors as differential pair; this conductor pair(and possibly several twisted pairs) is enclosed within an outer coppershielding braid to form a cable. Often each twisted pair may have an individual drain wire. Because the electromagnetic flux generated on thetwisted pair of a conductor are equal in magnitude and opposite indirection, effectively they cancel each other. Extending this concept to apair of twinax connector contacts, this can be envisaged as two adjacent,spaced contact elements contained within an outer (rectangular cross-section)grounding shell. This is a relatively inexpensive method tomaintain signal quality through an interconnection. Often this is referredto a "balanced pair" interconnection. Use of such twinax interconnectiontermination is often related to the use of cable, but similarly a twinaxconnector may be terminated on a PCB. In the latter case, instead of thecable twisting, the connector can be mounted on a PCB having pairs ofidentical tracks which are located spatially adjacent to each other, usuallyas part of a multi-layered structure.
Further, U.S. Patent No. 4,571,014 discloses primarily a backplaneinterconnection and not a cable-to-cable or cable-to-boardinterconnection.
Published European Patent No. 0 442 643 discloses a cableconnector formed of a plurality of shielded PCB assemblies. However, thisconnector does not use mirror image PCB orientation for forming twinaxconnectors. Further, this design utilizes a metal shield that envelopseach PCB assembly.
The PCT Patent Application WO97/02627 which was publishedthe 23 January 1997 after the priority date the 7 January 1997 of the present applicationdiscloses board to board connectors made from stacked modules, eachmodule being formed of a printed circuit board assembly and a cover.This application discloses high speed board to board connectors that haverelatively low manufacturing costs.
The object of the present invention is to provide a connector whichovercomes the disadvantages described above.
This object is obtained by the present invention by providing an electricalconnector according toclaim 1.
In order to provide shielding for matched pairs of conducting trackson the PCB, ground tracks may be provided between the conductingtracks on a first surface and a ground layer may be provided on a secondsurface opposite the first surface.
The covers are made of insulating material and may hold one ormore insulating substrates with conductive traces in opposed relationshipto form matched pairs of conductive traces. The covers, together with one or more associated PCB's, may form modules that are assembled in side-by-siderelationship in a housing to form a completed connector.
The connector may also comprise an insulating connector bodyaccommodating each of said one or more integrated PCB assemblies andprovided with a metallized shielding layer on its outer surface. Thereby,the electromagnetic interference caused by such a connector to theenvironment is further reduced. The connector body desirably includesstructure for receiving and securing PCB modules in alignment.
According to another feature of the invention, the PCB modulesinclude structure for retaining flexible conductors, such as wires orcables, in a position to be secured to traces on the PCB. The covers caninclude such retaining structures.

Brief Description of the Drawings

The present invention will be further illustrated with reference tothe drawings which are meant for illustration purposes only and notintended to limit the scope of the present invention.
In the drawings:
Figs. 1a - 1c show construction techniques broadly applicableto connectors embodying the invention;
Fig. 2 is a side elevational view of a PCB assembly according toone embodiment of the invention;
Figs. 3, 4 and 5 are fragmentary views showing the mounting ofterminals on the PCB assembly shown in Figure 2;
Figs. 6 - 6d show different views of an insulative cover to be usedin conjunction with the PCB assembly of Fig. 2 to form aterminal column module;
Figs. 7 - 7e illustrate an assembled terminal module formed of aPCB assembly as shown in Fig. 2 and a cover as shown in Fig. 6;
Figs. 8 - 8a and 9 are enlarged views showing portions of theintegrated terminal column module shown in Fig. 7;
Figs. 10 - 10c shown views of a connector housing for receiving aplurality of modules as illustrated in Fig. 7;
Figs. 11 - 11a and 11b show various views of a lead-in plate forthe housing shown in Fig. 10.
Fig. 12 illustrates two PCB assemblies having a mirror-imagerelationship;
Fig. 13 is a generalized cross-section of two PCB assembliespositioned in back-to-back relationship to form matched pair ortwinax conductor paths;
Fig. 14 shows a shielded pair module with spaced PCBassemblies;
Fig.15 is a rear view of an assembled connector having aplurality of shielded pair PCB assemblies;
Fig 16 is a rear view of an assembled connector havingindividually shielded signal traces;
Fig. 17a, 17b and 17c show several PCB arrangements forforming shielded connectors;
Figs. 18a and 18b are schematic circuit diagrams of thearrangements shown in Figs. 17a - 17b and Fig. 17c,respectively;
Figs. 19, 19a and 19b show a cover for use with cableconnectors;
Fig. 20a is an exploded isometric view of a twinax cableconnector module;
Fig. 20b is an isometric view of the module of Fig. 20a inassembled form and positioned for insertion into a connectorhousing;
Fig. 20c is an isometric view of a completed right angle cableconnector;
Fig. 21a is an exploded isometric view of a twinax straight cableconnector module;
Fig. 21b is an isometric view of the module of Fig. 21a inassembled form and positioned for insertion into a connectorhousing; and
Fig. 21c is an isometric view of a completed straight cableconnector.

Detailed Description of the Preferred Embodiments

Figures 1a - 1c generally show manufacturing steps for producing aright angle connector according to the invention in which standardmethods of producing printed circuit boards are used.
Figure 1a shows an insulatingsubstrate 16, formed for example ofconventional flat PCB material provided with several parallel conductingsignal tracks 11. Conducting ground tracks 10 may be provided betweenadjacent tracks 11. The outer mostconducting ground track 10 isprovided with aground contact terminal 7 to be connected to groundthrough the printed circuit board on which the connector is to bemounted. Methods of producing an insulatingsubstrate 16 with parallelconducting tracks 10, 11 are widely known in the field of manufacturingprinted circuit boards and need not be explained here.
Each of the conducting tracks 11 is connected to boardcontactterminals 7, theboard contact portions 15 of which extending beyond thecircuit substrate 16. Although theboard contact portions 15 are shownas press-fit terminals they might be replaced by suitable solder tailterminals. The other ends of the conducting tracks 11 are connected tosuitable contact terminals 4. Preferably, theterminals 4 and 7,respectively are fixed onto suitable solder pads formed at the ends oftraces 11. This can be achieved by conventional surface mount solderingtechniques.
An insulatingspacer 17 can be provided having a first series ofopenings 24 for accommodating the contact terminals 4 and a secondseries ofopenings 25 for accommodating at least part of theboard contactterminals 7. The recess 2 in themodule 1 is formed at the interface ofadjacent layers or laminations. That is, the recesses 2, for example, arebounded by thecircuit substrate 16, the edges ofopenings 24 or 25 andthecover 18. This allows the contacts to be secured onsubstrate 16 byconventional surface mounting or other bonding techniques.
An insulatingcover 18, optionally provided with a fully metallizedground layer 9, overlies thecircuit substrate 16. Preferably, thecover 18andspacer 17 are combined into a single molded part.
Figure 1b shows one integrated PCB assembly manufactured fromthe components shown in Figure 1a, i.e. an insulatingsubstrate 16 towhich an insulatingspacer 17 is attached and an insulatingcover plate18 attached to the insulatingspacer 17. The first series ofopenings 24 inthe insulatingspacer 17 form recesses 2, in which the receptacleterminals 4 are disposed to receive contact terminals of a matingconnector (not shown). It is to be understood that the receptacleterminals 4 shown in Figure 1a may be replaced by pins or hermaphroditecontact terminals.
As previously mentioned, instead of providing both a spacer and acover plate 18, only a cover plate could be provided in which suitablerecesses are made for accommodating the contact terminals 4 and theboard contact terminals 7. Such recesses would serve the same purposeasopenings 24, 25 inspacer 17 shown in Figure 1a. Alternatively, butless desirably from a cost standpoint, such recesses could be provided insubstrate 16.
Figure 1c shows several integrated PCB modules as shown inFigure 1b arranged parallel, side-by-side relationship for insertion into aconnector body 19. Theconnector body 19 may be made of any insulatingmaterial and may be provided with a metallized inner surface to enhancethe shielding effectiveness. Theconnector body 19 may be provided withsuitable guidingridges 23 and one ormore guiding extensions 22 forproperly connecting the assembled connector to a mating connector (notshown).
As is conventional, one or more locating and securingposts 21,receivable within a hole in a printed circuit board to which the connectorsto be connected, is provided at the bottom side of theconnector body 19.
Theconnector body 19 is provided with suitable lead-inholes 20 incorresponding relationship with each of the contact terminals 4. Each ofthe lead-inholes 20 is suitable for receiving a mating pin terminal of amating connector (not shown). The lead-inholes 20 are arranged incolumns and rows as is designated by arrows c and r.
Referring to Figure 2, thePCB assembly 30 comprises an insulatingsubstrate 31 of a material commonly commercially used for making PCBs.Thesubstrate 31 can be a resin impregnated fiber material, such as is sold under the designation FR4, having a thickness 0.4 mm, for example.On a first surface of thesubstrate 31, a plurality of signal traces 32 areformed by conventional PCB techniques. Eachtrace 32 extends from afirst portion of thesubstrate 31, for example adjacent the front edge asshown in Figure 2, to a second area or region of thesubstrate 31, such asthe bottom edge as shown in Figure 2. Thetraces 32 include contactpads at each end adapted to have metal terminals secured to them, as byconventional surface mounting techniques using solder. A plurality ofground or shielding traces 33 are also be applied to thesubstrate 31. Theshielding traces 33 are preferably disposed between each of the circuittraces 32. A terminal, such as acontact terminal 34 is mounted at thefirst end of eachtrace 32 and a connector mountingside terminal 35 ismounted on the second end of eachcircuit trace 32. An additionalshielding orground layer 36 may be applied to the remainder of thesubstrate 31. Aground terminal 37 is fixed onto theground layer 36, inalignment with theterminals 35.
A locatinghole 39 may be appropriately placed in thesubstrate 31.The locatinghole 39 preferably comprises a plated through hole forestablishing electrical connection with a grounding layer 38 (Figure 5)that may extend substantially over the entire back surface of thesubstrate 31. Small vias forming plated through-holes (not shown inFig.2) may be disposed in each of the ground tracks 33 so that the ground tracks 33, theshield layer 36 and theback shield layer 38 form ashielding structure for the signal traces 32 and associated terminals. Ifno shielding or limited shielding is desired, one or more of the shieldingstructures 33, 36 or 38 can be eliminated.
As shown in the fragmentary views of Figures 3 and 4,contactterminals 34 are formed as a one-piece stamping and can comprise a dualbeam contact having abase section 40 having an opposed pair ofupstanding portions 41. Aspring section 42 is cantilevered from each oftheupstanding portions 41 to define an insertion axis for a matingterminal, such as a pin from a pin header. Such a mating pin wouldengage thecontact portions 43 disposed at the end of eachcantileveredarm 42. The contact terminals also include a mounting section, such astheplanar member 44, that is adapted to be secured onto the end of thecircuit trace 32, typically bysolder 46. The latter can be accomplished byconventional surface mounting or other bonding techniques. As can berealized by the above description, the cantileveredarms 42 andcontactportions 43 define a contact mating or pin insertion axis that is generallyparallel to the plane ofsubstrate 31, but is offset from the surfacecarrying the conductive traces 32.
As illustrated in Figure 5, one preferred form ofconnector mountingterminal 35 includes a press-fit section 48 and a board mounting section49. The board mounting section 49 includes a generallyplanar base 50 with an upturnedtop tang 52 disposed along a top edge. A pair ofopposed side tangs 53 are also upturned from thebase 50. The mountingportion 49 is retained on thecircuit trace 32 bysolder fillets 54, againformed by conventional surface mounting solder techniques. Preferably,thetop tang 52 is spaced closely adjacent to or rests on the top surfacesof the side tangs 53 as shown in Figure 5.
Figures 6, 6a, 6b, 6c and 6d illustrate an insulative cover/spacermember 56, preferably molded from an appropriate polymeric insulatingmaterial. The cover includes a plurality of contact recesses 57 formedalong one edge. Each of therecesses 57 includes acontact preload rib58. A largecentral recess 59 may also be formed in the cover. A secondplurality ofterminal recesses 60 is formed along a second edge of thecover. Further, a locatingboss 62 is integrally formed with the cover andis sized and shaped to be received, with limited clearance, in the locatingopening 39 in thesubstrate 31. The cover further includes anupper rim63 extending from the rear of the cover to a location near therecesses 57.A bottom rim orsupport member 64 is formed on a portion of the bottomsurface of the cover. Thecover 56 further includes an upper locating andmountingrib 65, preferably in the form of a dove tail rib as shown. Asimilar but shorter mounting and locatingrib 66 is disposed on thebottom edge of the cover. Thesurfaces 67a and 67b form board restsurfaces against which asubstrate 31 is placed. Thesurfaces 67a and67b may carry an adhesive or alternately a double sided adhesive coated film (not shown) may be applied to extend from surface 67a tosurface67b.
It is noted that a half of one type of twinax contact module may beformed by associating aPCB assembly 30 with acover 56 to form amodule 69. Figure 7 is substantially an x-ray view through thecover 56ofcolumn terminal module 69. For ease in showing the location of theelements onsubstrate 31, with respect to features of thecover 56, theconductive traces and terminals are rendered in full line rather thanphantom view. ThePCB assembly 30 is located in the vertical directionby the upper and lower rim or mountingmembers 63, 64 and is located ina longitudinal manner by the locating boss 62 (see also Figure 7e). Thecontact terminals 34 are located in the contact recesses 57 and theconnector mounting terminals 35 are located in therecesses 60. Thepreviously mentioned adhesive or adhesive coated films onsurface 67aand 67b maintain the PCB assembly and cover 56 together.
Figure 7a is a sectional view taken along line AA of Figure 7 andshows thecontact terminals 34 located in the contact recesses 57. Theterminals 34 are positioned so that thecontact portions 43 bear againstthepreload ribs 58 to impart a desired preload on the cantileveredspringarms 42.
Figure 7b is a sectional view taken along line BB of Figure 7. Asshown in Figure 7b, thesubstrate 31 is essentially located in a verticalposition by therims 63 and 64.
As illustrated in Figure 7c, eachconnector mounting terminal 35has its mounting portion received within a correspondingrecess 60. Ifthe board mounting terminal is of a type that is likely to have a relativelyhigh axial force applied to it, such as a press-fit terminal, the surface 68(Figure 6d) of therecess 60 is advantageously located so that it bearsagainst theupturned tang 52 of the terminal. The views in Figures 7cand Figure 9 (discussed below) are taken substantially along section linecc of Figure 7.
Figure 7d is a fragmentary cross sectional view taken along line DDof Figure 7, showing the positioning of groundingterminal 37 in a similarfashion toterminals 35 shown in Figures 7c and Figure 9 (discussedbelow).
Figure 7e is a view of the back end of themodule 69 showing inphantom views the locatingboss 62 and the mounting portion ofterminal 37.
Figures 8 and 8a illustrate enlarged views of theconnector contacts34 located inrecesses 57 of thecover 56. Figure 8a is a cross sectionalview taken along line GG of Figure 8 and shows the positioning of thepreloadrib 58 with respect to thecontact portions 43.
Figure 9 illustrates the interaction of thecover 56 with theboardconnection terminal 35 when a downward force F is applied to the topedge of themodule 69. That force is transmitted by the cover to thepressing surface 68 formed by the top surface of therecess 60. As aresult, a vertical insertion force that is used to push the press-fit 48section into the hole T is applied directly to theupper tang 52 and theside tangs 53. In this manner, shear stress occurring at the solderconnection between the base 50 of the terminal and thecircuit trace 32 isminimized. In this manner, loosening or detachment of the terminal 35 isavoided. This is achieved, at least in part, by positioning thesurface 68so that it will engagetang 52 before therim 63 begins applying a verticalforce to the upper edge of thesubstrate 31. One way to accomplish this isto provide an initial, small clearance between therim 63 and the adjacentedge ofsubstrate 31. Additionally, the cover is designed so that asignificant proportion of the insertion force is applied directly to terminal35 so that stress at the terminal/conductive track interface is minimized.The structure disclosed is designed to withstand required press-fit pininsertion forces of 35-50 Newtons per pin.
Figure 10 is a cross sectional view taken along line HH of Figure10a and shows aconnector housing 70 having atop wall 72, abottom wall 76 and afront wall 78. Thetop wall 72 includes a plurality oflocating slots, for example thedove tail slots 73. One or more guidingridges 74 may be formed on a top surface of the top 72. The bottom 76also includes locating slots, for example thedove tail slots 77. Thefrontwall 78 includes a plurality ofopenings 79. Additional shielding can beprovided by metallizing appropriate surfaces of thehousing 70. Figure10c shows a bottom view of thehousing 70 shown in Figure 10.
Figure 11 is a front elevational view of a lead-inface plate 80 havinga plurality of tapered lead-insections 84 arranged in the form of a grid.Each of the lead-inportions 84 extends to apin insertion port 85. Aplurality of sleeves orhollow bosses 86 extend from the rear surface of theface plate 80 and are shaped and sized to be positioned and retained intheopenings 79 in thefront wall 78 ofhousing 70. The use of a separatelead-in plate is desirable when the interior surfaces of thehousing 70 areto be fully metallized. However, thehousing 70 can also be formed withthe lead-in plate integrally molded, where selective metallization or nometallization is utilized.
Figure 12 illustrates printed circuit board modules configured toprovide connectors having shield pairs of terminals. Themodule 30shown in the lower portion of Figure 12 is essentially the same as themodule illustrated in Figure 7 wherein the dotted lines illustrate thelocation of structures on the side ofcover 56 located on the reverse side of the cover adjacent PCB 31 (Figure 7C). For purposes of clarity, traces 32and 33 have been shown in full line rather than dotted or phantom form.The elements forming themodule 30 are the same as those discussed inconnection with Figures 2 - 9 and no further description thereof isbelieved necessary. PCB module 30' includes essentially the sameelements asmodule 30 and these have been designated by thedesignation. Module 30' differs frommodule 30 essentially in the aspectthat the elements of this module are arranged to constitute a mirror-imagewith a respect to line L.
Figure 13 illustrates a generalized cross-sectional view ofmodules30 and 30' arranged in back to back relationship to form a completeshielded pair module that can be placed in side by side relationship withsimilar modules to form a connector. In this arrangement, the backshielding layers 38, 38' of thePCBs 31, 31' are arranged adjacent oneanother to form the shielded pair module. Themodules 30, 30' can beheld in the illustrated relationship by insertion into housing 70 (Figure10) or, if desired, by a conductive adhesive layer applied to adjacent outersurfaces of shieldinglayers 38, 38'. In the shielded pair modules shownin Figure 13, the dimension X represents the centerline distance betweentheterminals 34 and 34', which essentially constitutes the contact pitchbetween the terminals. The dimension A represents the overall thicknessof the shielded pair module. As illustrated, the dimension A is twice thethickness of one of thePCB modules 30, 30. Preferably, the dimension A is chosen so that the terminal pitch X is maintained between adjacentshielded pair modules. Referring to Figure 14,spacers 90 having athickness represented by the dimension B may be placed betweenPCBmodules 30 and 30' to achieve a desired terminal pitch X.
Figure 15 is a rear view of a completed 5 x 6 connector (rows xcolumns) formed by juxtaposing three shielded pair modules arranged inside by side relationship withinhousing 70. Eachmodule 90 includes apair of juxtaposed PCB's 31, 31' on which press-fit terminals (such asshield terminals) 37, 37', are mounted. EachPCB 31, 31' is held by anassociatedinsulative cover 56, 56'. Thecovers 56, 56' have dove-tail ribs65, 65' fitted within dove-tail slots 73 in the housing. The dottedsquares92 represent the locations of theterminals 34, 34' and generallycorrespond to the location of theopenings 85 in the face-plate 80 (Figure11). The contact pitch X existing between adjacent columns at theintermating face of the connector also exists at the board mountinginterface atterminals 37. Each of these shieldedpair modules 90 carryfive shielded pairs of terminals and terminal leads in the 5 x 6configuration illustrated in Figure 15.
Figure 16 is a rear view of a connector essentially as illustrated inprior co-pending International Application Serial No. PCT/US96/11214filed 02 July, 1996. In this arrangement, thePCB modules 30 arearranged in theconnector housing 70 so that all of thePCB assemblies 30are oriented in the same way, for example, with thecover 56 disposed on the left-hand side and thePCB 31 disposed on the right-hand side. Thisresults in a connector having each terminal being substantially fullyelectrically isolated from all others in the connector. For comparison,Figures 17a, 17b, and 17c illustrate connectors embodying an aspect ofthe present invention. Figure 17a illustrates from a rear view one form oftwinax connector having shielded pairs of terminals and terminal leads.This arrangement differs essentially from that shown in Figure 15 byhaving the relative positions of thecovers 56, 56' and PCB's 31, 31'reversed. In this connector, the terminal pair modules 91 are formed byplacing thecovers 56, 56' in back to back relationship with the PCB's 31,31' forming the exterior surfaces of the module. In this arrangement, thesignal and ground traces 32, 32' and 33, 33', respectively are located infacing mirror-image relationship on the interior surfaces of the PCB's 31,31', with the outer-shieldinglayers 38, 38' disposed outwardly. Such anarrangement forms twinax pairs 93 of terminals that are substantiallyparallel through the conductor and have essentially identical electricalcharacteristics. These pairs are shown by the dottedenclosures 93 forthe left-hand most module 91. The connector shown in Figure 17b isessentially the same arrangement as that shown in Figure 17a, with theexception that instead of twocovers 56, 56', asingle insulative member57 is utilized to hold the opposedPCBs 31, 31'. In each of the modules91 the outer surfaces of themember 57 are configured similarly to theinterior surfaces of thecovers 56, 56'. Figure 17c essentially illustrates the arrangement previously discussed with respect to Figure 15. Insteadof using two PCBs, a single multi-layer PCB 31''may be employed havinga centrally located, substantially continuous central shield layer, with thesignal and shielding traces formed on opposed sides of the 31 in mirror-imagerelationship.
Figures 18a and 18b are schematic representations designed toillustrate the electrical differences between the Figures 17a-b type ofconnectors and the Figure 17c type of connector. Referring to Figure 18a,the pair ofinterconnection terminals 94 are electrically isolated by acommon shield S. Whereas, in Figure 18b each of theinterconnections94 of the pair are individually shielded. In either case, an electricallymatched pair of interconnections are formed to maintain essentially atwinax relationship through the interconnection.
The foregoing descriptions have been in the context of connectorsthat are attached to printed circuit boards. Figure 19 illustrates anarrangement for cable connectors. Figure 19 shows acover 100 for usewith a circuit board generally of the type previously described. The upperportion of thecover 100 is substantially similar to thecover 56 shown inthe previous embodiments. It includes on its upper and lower surfacesdove-tail ribs 165 and 166 that are designed to be received incorresponding dove-tail grooves in a housing, such ashousing 70 shownin Figure 10. A printed circuit board has a plated through hole for receiving the locatinglug 162. The locatingribs 163 and 164 are theequivalent of locatingribs 63 and 64 shown in Figure 6C and serve tolocate the PCB in the same manner. The PCB assembly to be associatedwith thecover 100 differs from those previously described essentially bythe absence of press-fit terminals 35 and 37.
Thecover 100 includes a retainingstructure 102 for retaining aflexible conductor, for example, a cable formed of a plurality of individualwires. The retainingstructure 102 includes anopening 104 for receivingthe cable. A suitable strain relief element or elements may be provided atthe location of opening 104 to enhance cable retention. The retainingstructure 102 preferably includes a plurality of routing pegs 106 that areuseful to separate individual wires that are to be attached to the PCB.Such individual wires are schematically illustrated by the dottedlines 108in Figure 19. The ends of thewires 108, 109 may be soldered to contactpads on the PCB that are coincident with the recesses 110 in thecover100. Subsequent to soldering thewires 108, 109 to the PCB, the PCB isassembled to thecover 100 and theindividual wires 108 are arrangedbetween thepegs 106. If the cable (not shown) includes one or moredrain lines, which can be represented by theline 109, these drain linescan be soldered to the shielding structures of the printed circuit boardsuch astraces 33,layer 36 and 38 by connection at an appropriatelocation, for example, the right hand at most location of the PCB that in the previous embodiment corresponds to the location of press-fit shieldterminal 37. For twinax cable connectors, shielded pair modules employtwocovers 100, one of which is a mirror-image of the other. Each one ofa twisted wire pair is connected to corresponding traces on each of theprinted circuit boards.
If each twisted pair has an individual drain, the drain wire can beconnected to anappropriate shielding trace 33.
Figures 20a - 20c illustrate the components of a typical cableconnector. The connector illustrated is a twinax connector but otherconfigurations are possible by varying the relative orientation and layoutof the modules. In this connector there are two mirror image PCB's 31and 31' placed in back to back relationship with shielding layers placednext to each other.Signal wires 108 are each attached to one of theconductive signal traces 32 on each of thePCBs 31 and 31', along abottom edge of each PCB. In a twinax connector, conductors from eachtwisted pair would be attached to corresponding signal traces on each ofthePCBs 31 and 31'. If a drain or shield 109 is present in the cable, itcan be secured to theshield portion 36. The securing of the variouswires to the PCB's is accomplished by conventional means, such assoldering or welding.
The shield traces 33 andshield portion 36 are interconnected to theshield layers 38 and 38' by plated vias 112 and the platedlocation hole39 as previously described.Covers 100 and 100' are secured onto therespective PCBs 31 and 31'. The retainer sections of each coversurround the ends of the wires attached to thePCBs 31 and 31'. Theretaining sections include thepegs 106, which provide strain relief andwire support functions.
The PCB's 31 and 31' may be held together by a conductiveadhesive or may be closely held together by the effect of thedove tail ribs165 and 165' and corresponding dovetail slots 73 and 77 in thehousing70, as the module is assembled in thehousing 70 as shown in Figure20b. A plurality of modules are arranged in the moldedplastic housing70, the interior surfaces of which may be metallized to provide additionalshielding. Theface plate 80 is secured tohousing 70 to form thecompleted right angle cable connector shown in Figure 20c.
Figures 21a - 21c show essentially the same elements illustrated inFigures 20a - 20c with the exception that thePCBs 33 and 33' areconfigured to provide a cable connection end at the rear edge of the PCB'srather than the bottom edge. The insulating covers 100 and 100' aremodified correspondingly to situate thecable retaining sections 102 and102' at the rear edges of the PCBs. The covers includepegs 106 forproviding support, organization, and strain relief. Thecovers 100 and100' may be secured together at engaging edges along the PCB's and atthe retaining sections, for example by adhesives or solvent or heatwelding.
The modules are then inserted intohousing 70 as shown in Figure21b and are retained in the housing as previously described. A completedstraight connector is formed by the insertion of a plurality of modules inside by side relationship into thehousing 70 and securing aface plate 80on the housing, as illustrated in Figure 21c.
The foregoing constructions yield connectors with excellent highspeed characteristics at relatively low manufacturing costs.
While the present invention has been described in connection withthe preferred embodiments illustrated in the various figures, it is to beunderstood that other similar embodiments may be used or modificationsand additions may be made to the described embodiment for performingthe same function of the present invention without deviating therefrom.Therefore, the present invention should not be limited to any singleembodiment, but rather construed in breadth and scope in accordancewith the recitation of the appended claims.

Claims

An electrical connector comprising:
a housing (70)
a circuit module (1; 30) mountable in the housing (70) comprising a pair of substantiallyparallel signal conductors (11, 32) disposed within the module (1; 30), eachextending from a first region of the module (1; 30) to a second region of themodule (1; 30), at least two electrical contact terminals (34), each terminal (34) beingelectrically connected to one of the signal conductors (11, 32) in the first region,said signal conductors (11, 32) being arranged substantially symmetricallyabout a longitudinal plane of the module (1;30), whereby the conductors (11, 32)constitute substantial mirror-images of each other about said longitudinalplane.
An electrical connector as in Claim 1, wherein each of the conductors (11; 32)comprise a circuit trace disposed on a circuit substrate (16; 31) included in themodule (1; 30).
An electrical connector as in Claim 2, wherein the traces are printedtraces.
An electrical connector as in Claim 2, wherein a pair module (30; 30') includes atleast two circuit substrates (31, 31') and each of the traces (32, 32') is disposed on oneof the circuit substrates (31, 31'), each of the circuit substrates (31, 31') being substantiallyplanar and parallel to the other.
An electrical connector as in Claim 2, wherein the circuit traces (32, 32') aredisposed on opposite sides of a single circuit substrate (16; 31).
An electrical connector as in Claim 1, wherein each conductor (31, 32) isflanked substantially over its length by a pair of shielding conductors (10, 33).
An electrical connector as in Claim 6, wherein the signal conductors (11, 32)and the shielding conductors (10, 33) comprise circuit traces on a circuitsubstrate (16, 31) and wherein the module (1, 30) further comprises at least one metallicshielding layer (30) disposed between the substantially symmetrically arranged signal conductor traces (11, 32).
An electrical connector as in Claim 7, wherein the module (1, 30) furthercomprises a pair of opposed shield layers (36, 38), each shield layer (36, 38) beingdisposed on one of two opposed exterior surfaces of the module (1, 30).
An electrical connector as in Claim 1, wherein a pair module (30; 30') comprisesa pair of spaced circuit substrates (31, 31') supported in facing relationship witheach signal conductor (32, 32') comprising a circuit trace disposed on one of thefacing surfaces, and wherein the module (30, 30') further comprises a commonsupport member (64, 67a, 67b) for supporting both of said circuit substrates (31, 31').
An electrical connector as in Claim 4, wherein the pair module (30; 30') furthercomprises a pair of support members (64, 67a, 67b) arranged in side by side relationship,each of the support members (64, 67a, 67b) carrying one of the circuit substrates(31, 31'), or wherein the pair module (30, 30') comprises a pair of circuit substrates (31, 31') arranged in a side by side relationship, each having an outwardlyfacing surface and the signal conductors (32, 32') comprise circuit traces, eachof the circuit traces being disposed on one of said outwardly facingsurfaces, and a pair of support members (64, 67a, 67b), each support member (64, 67a, 67b) beingdisposed adjacent one of the outwardly facing surfaces, or comprisingat least one additional circuit module (1; 30) mounted on the housing (70), saidadditional circuit module (1; 30) being substantially similar to the first mentionedcircuit module (30, 30').
A pair module (30, 30') for an electrical connector according to claim 4 comprising:
(a) a first circuit (31) substrate having a circuit trace (32) disposed thereon,the circuit trace (32) extending from a first region of the circuitsubstrate (31) to a second region of the circuit substrate (31) spacedfrom the first region;
(b) a second circuit substrate (31') having a second circuit trace (32') disposedtherein and extending from a first region of the secondsubstrate (31') to a second region thereof spaced from the firstregioncharacterized in that, the second circuit trace (32') being substantially in spacedmirror-image relationship with respect to the first circuit trace (32),said first and second circuit traces (32, 32') forming a twinax pair ofconductors.
A pair module (30, 30') as in Claim 11, and further comprising a substantially planarshield structure (38, 38') for electrically shielding the conductive traces (32, 32'), orwherein the first substrate (31) and the second substrate (31') comprise a pair ofcircuit boards, each board having two primary sides, with one of saidcircuit traces (32, 32') disposed on one of said primary sides of each circuitboard and a shield layer (38, 38') disposed on an opposite primary side of eachcircuit board, the circuit boards being arranged with the shield layer (38, 38') ofeach board in back to back relationship, or in opposed relationship, or wherein the first and second substrates (31, 31') comprise opposite sides of acircuit board.
A pair module (30, 30') as in Claim 12, wherein the circuit board further comprisesa shield layer (38, 38') disposed between the first and second sides.
A pair module (30, 30') as in Claim 11, and further comprising a common supportmember (64, 67a, 67b) for holding the first and second in said substantially opposedrelationship, the support member (64, 67a, 67b) including structure (63, 65, 66), for mounting themodule in a housing.
An electrical connector as in any one of the claims 1-10 comprising:
a plurality of circuit board modules (30), the modules (30) including at least one ofa shielded pair of twinax of conductive traces (32) each of said pair ofconductors (32) being located on a different module (30); and
a means for mounting the plurality of modules in substantially side byside relationship.
An electrical connector as in Claim 15, wherein each module (30) includesa cover element (100) for holding the circuit substrate (31) and said cover (100) includesretaining structure (102) for retaining flexible conductors (108) adjacent aregion of the circuit board, said retaining structure (102) being integrallyformed with the cover (100).
An electrical connector as in one or more of Claims 1 to 10 and 15to 16 comprising a cover (100) for covering each of the circuit substrates (31),each cover incorporating retaining means (102) for retaining flexible conductors(108) adjacent a region of each circuit board.