Abstract:
A communications connector with a flexible printed circuit board is provided. The flexible printed circuit board is electronically and mechanically connected to the plug interface contacts of the jack near the plug/jack interface, in order to provide effective crosstalk compensation. The flexible printed circuit board has fingers at one end allowing it to flex as individual plug interface contacts are depressed when a plug is installed into the jack. The flexible printed circuit board, or a flexible portion of a printed circuit board, is provided with elongated extensions for certain conductors to accommodate the connection of six-contact or eight-contact plugs to the connector.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit of U.S. Provisional Patent Application No. 60/699,823 filed Jul. 15, 2005. This application incorporates by reference in their entireties U.S. patent application Ser. No. 11/014,097, filed Dec. 15, 2004; U.S. patent application Ser. No. 11/055,344, filed Feb. 20, 2005; U.S. patent application Ser. No. 11/078,816, filed Mar. 11, 2005; U.S. patent application Ser. No. 11/099,110, filed Apr. 5, 2005; U.S. Provisional Application No. 60/587,416, filed Jul. 13, 2004; U.S. Provisional Application No. 60/637,024, filed Dec. 17, 2004. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates generally to electrical connectors, and more particularly, to a communication jack having crimped contacts secured to a flexible printed circuit.  
       BACKGROUND OF THE INVENTION  
       [0003]     In the communications industry, as data transmission rates have steadily increased, crosstalk due to capacitive and inductive couplings among the closely spaced parallel conductors within the jack and/or plug has become increasingly problematic. Modular connectors with improved crosstalk performance have been designed to meet the increasingly demanding standards. Many of these improved connectors have included concepts disclosed in U.S. Pat. No. 5,997,358, the entirety of which is incorporated by reference herein. In particular, recent connectors have introduced predetermined amounts of crosstalk compensation to cancel offending near end crosstalk (NEXT). Two or more stages of compensation are used to account for phase shifts from propagation delay resulting from the distance between the compensation zone and the plug/jack interface. As a result, the magnitude and phase of the offending crosstalk is offset by the compensation, which, in aggregate, has an equal magnitude, but opposite phase.  
         [0004]     Recent transmission rates, including those in excess of 500 MHz, have exceeded the capabilities of the techniques disclosed in the &#39;358 patent. Thus, improved compensation techniques are needed.  
     
    
     BRIEF DESCRIPTION OF FIGURES ILLUSTRATING PREFERRED EMBODIMENTS  
       [0005]      FIG. 1  is a front perspective view of a communications jack;  
         [0006]      FIG. 2  is an exploded perspective view of a contact assembly showing the use of a printed circuit board having a flexible portion;  
         [0007]      FIG. 3  is a plan view of a flexible portion of a printed circuit board;  
         [0008]      FIG. 4  is a perspective view of an upper conductive trace of the flexible portion of  FIG. 3 ;  
         [0009]      FIG. 5  is a perspective view of a lower conductive trace of the flexible portion of  FIG. 3 ;  
         [0010]      FIG. 6  is a cross-sectional view along the line  6 - 6  of  FIG. 3 ;  
         [0011]      FIG. 7  is a cross-sectional view along the line  7 - 7  of  FIG. 3 ;  
         [0012]      FIG. 8  is a plan view of a printed circuit board showing a flexible portion and a rigid portion;  
         [0013]      FIG. 9  is a diagram showing a side view and a plan view of jack contact points of a flexible portion of a printed circuit, with first and eighth connection extensions shown in extended positions;  
         [0014]      FIG. 10  is a diagram showing a side view and a plan view of jack contact points of a flexible portion of a printed circuit, with first and eighth connection extensions shown in bent positions;  
         [0015]      FIG. 11  is a side cross-sectional view of a communications jack showing the attachment of a flexible portion of a printed circuit board to plug interface contacts;  
         [0016]      FIG. 12  is a view of the detail “A” of  FIG. 11 ;  
         [0017]      FIG. 13  is a side cross-sectional view of a communications jack showing the bending of plug interface contacts upon insertion of a six-contact plug;  
         [0018]      FIG. 14  is a view of the detail “B” of  FIG. 13 ;  
         [0019]      FIGS. 15-17  are step-by-step side views showing the attachment of a flexible portion of a printed circuit board to crimped and welded plug interface contacts;  
         [0020]      FIG. 18  is a detailed view showing the jack contact point of a flexible portion of a printed circuit board held within a crimped and welded plug interface contact;  
         [0021]      FIG. 19  is a side view of a plug interface clip contact; and  
         [0022]      FIG. 20  is a side view of a plug interface clip contact with a flexible printed circuit clipped to the contact.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0023]      FIG. 1  is a perspective view of a communications jack  10  according to one embodiment of the present invention. The jack  10  includes a main jack housing  12  and a rear jack housing  14  attached to the main jack housing  12 , for example via housing clips  16 . The rear jack housing  14  may be provided with passageways for insulation-displacement contacts (IDCs)  18  (shown in  FIG. 2 ). A wire cap  20  provides an interface to a twisted pair communication cable. Alternatively, a punch-down block may be incorporated into the communications jack  10 . The main jack housing  12  comprises a receptacle  22  for receiving a communications plug, and plug interface contacts  24  within the receptacle  22  make contact with contacts of the plug.  
         [0024]     The plug interface contacts  24  are held within a contact carrier assembly  26  shown in  FIG. 2 . The contact carrier assembly  26  comprises a contact sled  28  and a vertical support  30  adapted to hold a printed circuit board (PCB)  32 . The printed circuit board  32  comprises a flexible portion  34  having jack contact points  36  for attachment to the plug interface contacts  24 . The PCB  32  further comprises a rigid portion  38  to which the IDCs  18  are electrically and mechanically attached (for example, via compliant pins). The PCB  32  provides electrical connection between the plug interface contacts  24  and the IDCs  18 , and further provides crosstalk compensation for communication signals traveling through the communications jack  10 .  
         [0025]     A plan view of the flexible portion  34  of the PCB  32  is shown in  FIG. 3 . Jack contact points  36   a - 36   h  correspond to first through eighth plug interface contacts  24 . Each of the first through eighth jack contact points  36   a - 36   h  has a corresponding conductive trace  1 - 8  on the PCB  32 . In the plan view of  FIG. 3 , conductive traces along the top of the flexible portion  34  are shown with solid lines, and conductive traces along the bottom of the flexible portion  34  are shown with dotted lines.  
         [0026]     The compensating circuitry of the PCB  32  is divided into zones similarly to the division shown in pending U.S. patent application Ser. No. 11/078,816 filed on Mar. 11, 2005. Specifically, the compensating circuitry of the present invention is divided into six Zones, A-F, as described in the &#39;816 application, and further incorporates a seventh zone, Zone G.  
         [0027]     Zone A is a transition zone from the jack contact points  36   a - 36   h  to the near-end crosstalk (NEXT) compensation zone.  
         [0028]     Zone B is the NEXT compensation zone.  
         [0029]     Zone C is a transition zone from the NEXT compensation zone to the NEXT crosstalk zone.  
         [0030]     Zone D is a compensation zone to compensate for the jack contacts.  
         [0031]     Zone E is a NEXT crosstalk zone.  
         [0032]     Zone F is a neutral zone which connects the NEXT crosstalk zone to IDC sockets  40  as shown in  FIG. 8 .  
         [0033]     Zone G is a variable compensation zone which reduces NEXT compensation as frequency increases.  
         [0034]      FIG. 3  shows the approximate lengths of Zones A, B, C, and E in inches.  
         [0035]     Within Zones B, D, and F, some conductive traces have capacitive plates that allow for capacitive compensation between conductors. These capacitive couplings are labeled in  FIG. 3  as “C x,y ” where x is the corresponding conductive trace along the top of the flexible portion  34  and y is the corresponding conductive trace along the bottom of the flexible portion  34  that is capacitively coupled at that coupling. For example, C 2,5  as shown in  FIG. 3  is a capacitive coupling between the second conductive trace on the top and the fifth conductive trace on the bottom.  
         [0036]     All of the conductive traces except the first, the seventh, and the eighth transfer between the top and bottom of the flexible portion  34  through conductive vias  46   a - g  as shown in  FIGS. 3-5 .  
         [0037]     The flexible portion  34  of the PCB  32  of the present invention incorporates additional features that help to accommodate the use of either six- or eight-contact plugs in the communications jack  10 . As shown in  FIG. 3  and as described in more detail below, elongated connection extensions  42   a  and  42   h  are provided for the first and eighth jack contact points  36   a  and  36   h.  Further, first and second slits  44   a  and  44   b  are cut into the flexible portion  34  to allow the elongated connection extensions  42   a  and  42   h  to bend more than the connection extensions of the second through seventh jack contact points  36   b - 36   g.    
         [0038]      FIGS. 6 and 7  show cross-sectional views of the flexible portion  34 , respectively, along the lines  6 - 6  and  7 - 7  of  FIG. 3 .  FIG. 6  shows a cross-section through a contact point via  48  where the first jack contact point  36   a  is connected to the first plug interface contact  24 . The cross-section shows a flexible core  50  manufactured, for example, of KAPTON polyimide film. Contact pads  52  are provided along the top and bottom layers in the area of the jack contact points  36 . The via  48  is conductive and may be copper plated.  FIG. 7  shows a cross-section through connection extensions  42   a  and  42   b,  respectively associated with the first and second conductors as shown in  FIG. 3 . Each of the cross-sections shows a flexible core. A trace  1  associated with the first conductor is shown on the bottom layer in  FIG. 7 , and a trace  2  associated with the second conductor is shown on the top layer.  
         [0039]      FIG. 8  is a plan view of the printed circuit board  32  showing the flexible portion  34  and the rigid portion  38 . The rigid portion includes the IDC sockets  40  and the conductive traces of Zone F.  
         [0040]     Turning now to  FIGS. 9 and 10 , two diagrams illustrate the adaptation of the flexible portion  34  of the PCB to accommodate both six- and eight-conductor plugs. As described in U.S. patent application Ser. No. 11/078,816 and further as shown in  FIG. 10 , the plug-jack interface is disposed directly above the contact between the plug interface contacts  24  and a flexible circuit board (or flexible portion of a circuit board). These contact locations are approximately located on a straight line when no plug is installed (as shown in  FIGS. 11 and 12 ) or when a standard eight-contact plug is installed. However, when a six-contact plug is installed (as shown in  FIGS. 13 and 14 ), contacts  1  &amp;  8  deflect more than contacts  2  to  7 .  
         [0041]     The Zone A connection extensions  42   a  and  42   h  which connect traces  1  and  8  to jack contacts  1  and  8  have been lengthened—as shown in  FIG. 9 —and an “S” bend—as shown in  FIG. 10 —has been incorporated to facilitate the additional deflection of contacts  1  and  8  compared to the deflection of contacts  2  to  7  when a six-contact plug is installed in the jack.  
         [0042]     As shown in  FIGS. 13 and 14 , the longer connection extension  42   h  associated with the eighth trace allows for the greater deflection of the plug interface contact  24   h  (associated with the eighth conductor) when a six-contact plug is inserted into the receptacle  22 .  
         [0043]     A preferred design of the mechanical and electrical connection of the flexible portion  34  of the PCB  32  to the plug interface contacts  24  adjacent to and on the opposite side of the plug-jack interface  54  is shown in  FIGS. 15-17 . The connection is made by bending the free tips  56  of the plug interface contacts  24  back on themselves, as shown in  FIG. 15 , and by spot-welding two sections  58  and  60  of each contact together adjacent to the connection extensions  42  of the flexible portion  34  of the PCB  32 . The connection extensions  42  are sandwiched between the two sections  58  and  60  of each contact. The spot-welding step as shown in  FIGS. 16 and 17  may be performed with welding electrodes  62   a  and  62   b.    
         [0044]     Crimping and welding the contacts as described provides frictional force allowing the plug interface contacts to grip the connection extensions  42 . As shown in  FIG. 18 , the plug interface contacts  24  may be provided with gripping features  64  in the region where they contact the contact point via  48 , beneath the plug-jack interface  54 . The grip of the plug interface contacts  24  on the via  48  can be enhanced by a number of methods such as coining, serrating, or abrading the contacts or roll-forming teeth on the contacts  24 .  
         [0045]      FIGS. 19 and 20  show an alternative way to connect a flexible printed circuit board or a flexible portion  34  of a circuit board to a jack contact. In this embodiment, the jack contacts are clip contacts  66  that are provided with first and second bends  68  and  70 . The connection extensions  42  of the flexible portion  34  of a circuit board are held beneath the plug-jack interface by friction between the second bends  70  of the clip contacts  66  and straight portions  72  of the clip contacts.  
         [0046]     While the discussion above addresses the connection of a flexible portion of a PCB to plug interface contacts, it is to be understood that this connection method may also be used with flexible printed circuits (FPCs) that do not contain rigid portions.  
         [0047]     While the particular preferred embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the teaching of the invention. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only and not as limitation.