Abstract:
An electrical connector module including a housing and an array of electrical contacts within the housing. The electrical contacts include a plurality of signal conductors and a plurality of ground conductors. Ground coupling bars are used with at least two contact portions for contacting ground conductors. The connector includes slots enabling insertion of the ground coupling bar in a longitudinal direction of the ground coupling bar.

Description:
FIELD OF THE DISCLOSURE 
     In general, the invention relates to the field of electrical connectors, in particular to a high speed electrical connector comprising an insulating housing and a plurality of electrical conductors. 
     BACKGROUND OF THE DISCLOSURE 
     Electrical connectors provide signal connections between electronic devices using signal conductors. Often, the signal conductors are so closely spaced that undesirable interference, or “cross talk”, occurs between adjacent signal conductors. Cross talk occurs when a signal in one signal conductor induces electrical interference in an adjacent signal conductor due to interfering electrical fields, thereby compromising signal integrity. Cross talk may also occur between differential signal pairs. Cross talk increases with reduced distance between the interfering signal conductors. Cross talk may be reduced by separating adjacent signal conductors or adjacent differential signal pairs with ground conductors. 
     With electronic device miniaturization and high speed signal transmission, high signal integrity electronic communications and the reduction of cross talk become a significant factor in connector design. It is desired to provide an improved connector reducing the problematic occurrence of cross talk, especially for high speed connectors. It is further desired to provide a connector allowing easy assembly and customizing of grounding provisions. 
     SUMMARY OF THE DISCLOSURE 
     In an aspect of the invention an electrical connector assembly is provided, comprising a housing and a plurality of electrical conductors within the housing. The electrical conductors include a plurality of signal conductors and a plurality of ground conductors. The housing comprises at least one slot enabling insertion of a ground coupling bar from outside in a longitudinal direction of the ground coupling bar. The at least one slot is positioned adjacent a line, e.g., a column or a row, of conductors including ground conductors. The ground coupling bar comprises contact portions for contacting the ground conductors when inserted in the slot. 
     This way the frequency of a cross talk resonance may be shifted by establishing an additional contact to ground for the ground conductors. Since the ground bar can be inserted in its longitudinal direction from outside, it is possible to provide a slot which is easily accessible for placing, removing or rearranging ground coupling bars. The ground coupling bar can selectively be placed or removed during or after assembly of the connector. The arrangement of ground contacts and signal contacts can be customized by a user by selectively positioning ground coupling bars in selected slots. 
     A connector according to claim  3  and/or  4  achieves better contact between the ground coupling bar and the ground conductors. 
     The slot can be positioned between two lines of conductors, wherein the conductors of at least one of the two lines comprise ground conductors configured to contact the ground coupling bar when inserted in the slot. In such a case, a connector according to claim  4  or  5  can be used. Ground conductors of two adjacent columns or rows of ground conductors can be contacted by the same ground coupling bar. 
     With the connector of claim  6  a shouldered top end forms a stop for the ground coupling bar. 
     With the connector of claim  7  erratic positioning of the ground coupling bar can effectively be prevented. The polarization features can for instance include a matching asymmetrical configuration of the shouldered top end and the slot in the housing. 
     With a connector according to claim  8  or  9 , a connector is provided comprising a plurality of subassemblies or modules adapted for connection to a contact panel having a ground conductor. The modules can for instance be planar and be arranged substantially parallel and in side by side relationship and comprise a module housing and a plurality of signal conductors and/or ground conductors. At least a portion of the conductors can be arranged in the module housing, e.g., in a plurality of pairs for differential signal transmission and a plurality of ground conductors separating different pairs. 
     Such a connector accommodates a relatively large number of mutually adjacent differential signal pairs with reduced cross talk at one or more predetermined signal frequencies. 
     Thus, a connector is provided which allows a relatively large number of differential signal pairs, while cross talk between adjacent differential signal pairs may be substantially reduced. 
     The contact ends of such a connector may include a mounting end, e.g., for mounting on a circuit board, and/or a mating end, e.g., for cooperation with a matching counterconnector. 
     With the connector of claim  10  or  11  a direct contact can be established between the ground coupling bars and the ground shield. 
     In a connector of claim  12 , the ground coupling bars are fixated after insertion by the resilient members of the ground shield. 
     With the connector of claim  13  the resilient blades of the ground shield contribute to the shielding at the location of the openings in the ground shield. 
     In a further aspect a ground coupling bar is disclosed, which can for instance be or comprise a metal sheet part. 
     In a further aspect a tool is provided according to claim  14 . This tool can be used to push one or more ground coupling bars out of the connector, e.g., against the action of resilient members of the ground shield engaging the top ends of the ground coupling bars. Such a tool is particularly useful for connectors having ground coupling bar receiving slots which are accessible from outside from opposite ends. 
     In another aspect, a method is provided for assembling a connector comprising a plurality of conductors, including a plurality of signal conductors and a plurality of ground conductors. The conductors are arranged in modules, e.g. planar modules, carrying one or more lines of conductors having contacting ends and a lead frame portion extending between the contacting ends. The modules are arranged within a housing, wherein recesses in adjacent modules jointly define a ground coupling bar receiving slot, which is in line with an opening in the housing. In the recesses the conductors are at least partly uncovered. Subsequently a ground coupling bar is inserted into the ground coupling bar receiving slot via the corresponding opening in the housing. The ground coupling bar is configured to contact one or more of the uncovered parts of the conductors. With such an assembly method the ground coupling bar locks the modules within the housing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The drawings show embodiments of a connector and connector modules by way of example, the drawings being explained in more detail below. In the drawings: 
         FIG. 1A  shows an exemplary embodiment of a connector in perspective view; 
         FIG. 1B  shows the connector of  FIG. 1B  without ground shield; 
         FIG. 2  shows a cross section of the connector along line II-II in  FIGS. 1A and 1B ; 
         FIG. 3A  shows a first exemplary embodiment of a ground coupling bar; 
         FIG. 3B  shows a second exemplary embodiment of a ground coupling bar; 
         FIG. 4A and 4B  show an exemplary embodiment of a subassembly of the connector of  FIGS. 1A and 1B ; 
         FIG. 5  shows an exemplary embodiment of a removal tool; 
         FIG. 6  shows the connector of  FIGS. 1A and 1B  during removal of the ground coupling bars. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       FIGS. 1A and 1B  show different perspective views of an exemplary right angle electrical receptacle connector  1  adapted to electrically connect one device to another device, such as printed circuit boards, electronic apparatus and/or cables, provided with a corresponding header (not shown). A suitable connector may take other forms such as a vertical or horizontal electrical connector or one connecting devices at different angles. 
     The shown receptacle connector  1  has a mating end  2 , and a mounting end  3 . The mating end  2  can for instance be configured to cooperate with a header. The mounting end  3  can for instance be configured to contact a panel or printed circuit board. 
     The connector  1  comprises a plurality of modules or subassemblies  4 , shown in more detail in  FIGS. 4A and 4B . The subassemblies  4  are retained in an insulating connector housing  6  covered with a ground shield  7  with clips  8  for engaging the ground shield of a mating header connector (not shown). 
     As shown in  FIGS. 4A and 4B  each subassembly  4  comprises a column of conductors  10  extending between the mating end  2  and the mounting end  3 . At the mating end  2 , the subassembly  4  comprises a front section  11  extending below a back section  12  of the subassembly  4 . At the upper side the front and back sections  11 ,  12  are substantially flush. 
     At the mating end the conductors  10  comprise two opposite flexible beams  13 ,  14  projecting from the front section  11 . The flexible beams  13 ,  14  provide a dual beam mating end for mechanically and electrically engaging the contacts of a mating header (not shown). The beams  13 ,  14  have free ends  15  curved towards each other to clamp the mating header contact (not shown). The other ends of the beams  13 ,  14  are spaced by a web portion  16 . 
     Each subassembly  4  comprises a first and a second interconnected insert moulded lead frame assembly (IMLA)  17 ,  18 . As is particularly shown in the cross section in  FIG. 2 , each first lead frame subassembly  17  comprises an upper rib  19  at its upper edge and a lower rib  20  at the lower edge of the front section  11 . Each second lead frame assembly  18  is held between the ribs  19 ,  20  of the first lead frame assembly  17 . In the exemplary embodiment of the drawings the first lead frame assembly  17  comprises a column of three conductors  10  having their web portion  16  at their left side. The second lead frame assembly  18  comprises a column of two conductors  10  having their web portion  16  at their right side. This way, the flexible beams  13 ,  14  held by the first lead frame assembly  17  are in line with the beams  13 ,  14  with the second lead frame assembly  18 . 
     At the mounting end  3  the conductors  10  are provided with any suitable terminal for establishing an electrical and mechanical connection with an electrical device. In the shown exemplary embodiment, the terminals  21  include eye-of-the-needle press fit contacts for circuit board mounting. Alternatively, these terminals may comprise a solder ball soldered to a solder pad on the electrical device, or be configured to be inserted into a plated through-hole. 
       FIG. 2  shows a cross section along line II-II in  FIG. 1 . The insulating connector housing  6  comprises partitions  22  partitioning the inner space of the housing  6  into cells  23 , each cell  23  encasing two subassemblies  4 . In each cell  23  the ribs  19 ,  20  of the first lead frame assemblies  17  point in the same direction, which is opposite to the pointing direction of the ribs  19 ,  20  of the first lead frame assemblies  17  in an adjacent cell  23 . Conductors  10  arranged close to the partitions  22  of the cell  23  form signal conductors  24 . Two signal conductors  24  at opposite sides of a partition form a differential pair (encircled in  FIG. 2 ). Conductors  10  in the two middle columns in a cell  23  form ground conductors  25 . Each differential pair of signal conductors  24  are flanked by ground conductors  25 . 
     The conductors  10  in the lead frame assemblies  17 ,  18  are embedded in a casing  26  of an insulating material. The cross section of  FIG. 2  shows the subassemblies  4  at a point where a recess  27  (see  FIG. 4B ) interrupts the insulating casing  26  uncovering lead portions  28  of the conductors  10 . 
     A T-shaped sheet metal ground coupling bar  29  is inserted between the two subassemblies  4  in each cell  23  via the recesses  27 .  FIG. 3A  shows an exemplary embodiment of such a ground coupling bar  29 . The ground coupling bar  29  comprises a longitudinal main body  30  with a broadened head  31  on its top end. The main body  30  comprises one side with three cut-outs  32  having an inverse J-shaped outline defining resilient fingers  33  which can be resiliently bent in a lateral direction. At the opposite side the main body  30  is provided with similar cut-outs  34  and resilient fingers  35 , which are mirrored and arranged in a staggered manner relative to the cut-outs  32  and fingers  33  of the first side of the main body  30 . To reduce the contact surface between the resilient fingers  35  and the ground conductors  25  the free ends of the resilient fingers  35  are provided with a flattened or coined bulged end  36 . 
     The insulating housing  6  comprises openings  37  (see  FIG. 2 ) allowing passage of the ground coupling bars  29 . The ground shield  7  also comprises openings  38  in line with the openings  37  in the housing  6 . The openings  37  in the housing  6  and the heads  31  of the ground coupling bars  29  are asymmetrically configured to form a polarized fit, so the heads  31  of the ground coupling bars  29  can only fit into the openings  37  in a single orientation. In this orientation the three fingers  33  at the first side of the ground coupling bar  29  engage the three lead portions  28  embedded in a first lead frame assembly  17 , while the free ends  36  of the two fingers  35  at the opposite side of the ground coupling bar  29  engage the two lead portions  28  in a second lead frame assembly  18 . This way, the ground coupling bar  29  connects the ground conductors. 
     A second example of a ground coupling bar is shown in  FIG. 3B . This ground coupling bar  40  has only one side with two inverse J-shaped cut outs  34  and fingers  35 . At the opposite side, the ground coupling bar  40  is provided with two spacers  41 . These spacers  41  are positioned in such a way that they contact the adjacent second lead frame assembly  18  at a position centrally between two conductors  10 . 
     The ground shield  7  covering the insulating housing  6  of the connector  1  is provided with resilient contacting blades  42  positioned to engage the heads  31  of the ground coupling bars  29 ,  40 . The heads  31  abut the top surface of the ribs  19  of the respective first lead frame assembly  17 . In line with the opposite ends of the ground coupling bars  29 ,  40  the housing comprises a further opening  43  (see  FIG. 2 ). 
       FIG. 5  shows a pressure tool  48  for removal of the ground coupling bars  29 ,  40 . The pressure tool  48  comprises a main body  49  with a row of equidistantly arranged teeth  50 . The teeth  50  fit into the openings  43  in the housing  6  near the lower ends of the ground coupling bars  29 ,  40 . The distance between the teeth  50  corresponds to the distance between the openings  43 . This way, the teeth  50  can be inserted in the openings  43  to push against the lower ends of the ground coupling bars  29 ,  40 . 
       FIG. 6  shows the connector  1  during removal of the ground coupling bars  29 ,  40 . With the aid of the tool  48 , the ground coupling bars  29 ,  40  are pushed against the action of the resilient blades of the ground shield  7  until they are out of the openings  37 . 
     It should be noted that the illustrations and discussions of the embodiment shown in the figures are for exemplary purposes only, and should not be construed limiting the disclosure, e.g., references to directions such as “horizontal” or “vertical” only relate to the orientation of parts as shown in the figures unless stated otherwise. The skilled person will appreciate that several variations are comprised within the scope of the appended claims. Additionally, it should be understood that the concepts described above with the above-described embodiments may be employed alone or in combination with any of the other embodiments described above. It should be further appreciated that the various alternative embodiments described above with respect to one illustrated embodiment can apply to all embodiments as described herein, unless otherwise indicated. 
     It should further be noted that in the appended claims, the word “comprise” does not exclude other elements and the indefinite article “a” or “an” does not exclude a plurality.