Abstract:
A receptacle connector ( 100 ) including a number of frames  12  transversely stacked together, each frame comprising: a conductive housing ( 120 ); a number of insulating stabilizers ( 3 ) mounted in the conductive housing; and plural differential pairs of contacts ( 4 ) each separately molded in a corresponding stabilizer, each contact of a differential pair of contacts having an outer edge ( 404 ) embedded into the stabilizer, an opposing inner edge ( 405 ), and two side edges ( 406 ) each connecting the inner edge and the outer edge, said side edge at least partially exposing to air; wherein each differential pair of contacts have different regions spaced different distances.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application relates to U.S. application Ser. No. 13/772,232, filed Feb. 20, 2013. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present disclosure relates to a backplane receptacle connector, and more particularly to a backplane receptacle connector having an improved frame. 
         [0004]    2. Description of Related Art 
         [0005]    U.S. Pat. No. 6,379,188 issued to Cohen et al. on Apr. 30, 2002 discloses a receptacle connector mounted on a daughter board for transferring differential signals to and from a header on a backplane or main circuit board. The receptacle connector has plural lead frames transversely stacked together. Each lead frame has a plurality of signal contacts or leads molded in a plastic housing. Windows are provided over leads to equalize the delay for signals traveling in long leads of each differential pair. As disclosed, it is not necessary that the “window” extend all the way to the surface of the conducting signal contact. Also, the “window” could be partially filled with plastic and partially filled with air, which would still have the effect of lowering the effective dielectric constant of the material above the long leg. Moreover, to counter one drawback of placing a window in the dielectric material, namely changing the impedance of the signal contact in the region below the window, other adjustments can be made to keep the impedance constant along the length of the signal conductors. One way that the impedance can be kept constant is by changing the width of the signal conductors. The signal conductors may have a width in one region and a broader width in the region of the windows. The dimensions are chosen to match the impedance based on the relative dielectric constant between the two regions. The technique of altering the width of the signal contacts in window regions is useful regardless of why the window is formed in the connector and is not limited to windows formed to equalize delay. As disclosed, some prior art connectors use windows over substantial portions of all the signal contacts to increase impedance of all the signal contacts. 
         [0006]    U.S. Pat. No. 6,293,827 issued to Stokoe on Sep. 25, 2001 discloses a receptacle connector including a plurality of wafers or frames. The frame has a plurality of differential pairs of signal conductors. Air space may be provided between intermediate portions of each pair to increase the coupling between the signal conductors in a pair, which might reduce noise in a differential configuration. Alternatively, air space might increase the impedance of the differential pair. As disclosed, in connector design, it is often desirable for the impedance of the signal conductors to match the impedance of traces in a printed circuit board to which the connector is attached. Thus, in some cases it will be desirable to adjust the shape of the housings in the vicinity of the signal conductors in order to adjust the impedance. 
         [0007]    A receptacle connector having an improved frame structure is desired. 
       SUMMARY OF THE INVENTION 
       [0008]    Accordingly, an object of the present invention is to provide a receptacle connector having an improved lead frame. 
         [0009]    In order to achieve the object set forth, a receptacle connector comprises a plurality of frames transversely stacked together, each frame comprising: a conductive housing; a plurality of insulating stabilizers mounted in the conductive housing; and plural differential pairs of contacts each separately molded in a corresponding stabilizer, each contact of a differential pair of contacts having an outer edge embedded into the stabilizer, an opposing inner edge, and two side edges each connecting the inner edge and the outer edge, said side edge at least partially exposing to air; wherein each differential pair of contacts have different regions spaced different distances. 
         [0010]    Each differential pair of contacts are spaced: a first distance between the inner edges where each contact has both side edges partially exposed to air and the inner edge totally exposed to air; a second distance between the inner edges where each contact has one side edge partially exposed to air and the inner edge at least partially exposed to air; and a third distance between the inner edges where each contact has only one side edge partially exposed to air; wherein the first distance is less than the second distance, and the second distance is less than the third distance. 
         [0011]    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 
         [0012]      FIG. 1  is an assembled perspective view showing a receptacle connector in accordance with the present invention; 
           [0013]      FIG. 2  is an assembled perspective view showing a header for mating with the receptacle connector; 
           [0014]      FIG. 3  is a partially assembled perspective view showing the receptacle connector of  FIG. 1 , with one frame thereof separated out; 
           [0015]      FIG. 4  is an exploded view showing the frame as shown in  FIG. 3 ; 
           [0016]      FIG. 5  is another exploded view of the frame as shown in  FIG. 3 ; 
           [0017]      FIG. 6  is an exploded view showing a conductive housing and an insulating spacer seen in  FIG. 4 ; 
           [0018]      FIG. 7  shows a contact module as shown in  FIG. 4 ; 
           [0019]      FIG. 8  is a side view of the contact module as shown in  FIG. 7 ; 
           [0020]      FIG. 9  is a view similar to  FIG. 8 , omitting an insulating stabilizer thereof; 
           [0021]      FIG. 10A  is a cross-sectional view of the contact module taken along line A-A in  FIG. 8 ; 
           [0022]      FIG. 10B  is a cross-sectional view of the contact module taken along line B-B in  FIG. 8 ; 
           [0023]      FIG. 10C  is a cross-sectional view of the contact module taken along line C-C in  FIG. 8 ; 
           [0024]      FIG. 10D  is a cross-section of the contact module taken along line D-D in  FIG. 8 ; and 
           [0025]      FIG. 11A-11D  are views similar to  FIG. 10B , showing respective cross-sections of varied designs of the insulating stabilizer according to various embodiments of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0026]    Reference will now be made in detail to the preferred embodiment of the present invention. 
         [0027]    Referring to  FIGS. 1-3 , a receptacle connector  100  in accordance with the present invention is designed to be mounted to a printed circuit board  500  and mated with a header  200 . The header  200  includes a U-shaped base housing  220 , a plurality of terminal module  210  each having a pair of terminals  211  molded therein, and a plurality of shielding blades  230 . 
         [0028]    The receptacle connector  100  includes a number of frames  12  transversely stacked together, a L-shaped retainer  11 , and a number of grounding bridges  17 . The retainer  11  is preferably punched from a metal plate. The retainer  11  comprises a top wall  111  and a rear wall  112 . The retainer  11  defines a number of cutouts  1110  on a front edge of the top wall  111 , a number of cutouts  1121  on a lower edge of the rear wall  112 , and a number of cutouts  1122  between the top wall  111  and the rear wall  112 . The grounding bridge  17  has a base portion  170 , and a plurality of grounding legs  171  each extending downwardly from the base portion  170  configured for mounting into a mounting hole  501  on the printed circuit board  500 . 
         [0029]    Referring to  FIGS. 4-9 , each frame  12  includes a conductive housing  120  having a first side  128  and an opposite second side  129 . The conductive housing  120  is made from die casting metal or conductive plastic, or insulating piece plated with metal plating. In a preferred embodiment, the conductive housing  120  is made from thermoplastic plated with metal material, such as Chromium, Copper, Tin or Gold. The first side  128  defines a plurality of grooves  1282  thereon. The frame  12  further includes a plurality of contact modules  30  and a plurality of insulating spacers  16 . The contact module  30  comprises an insulating stabilizer  3  and a pair of differential contact  4  insert-molded therein. The insulating spacer  16  is mounted in the groove  1282  and aligned to a front side of the insulating stabilizer  3 , such that the groove  1282  is filled with a contact module  30  and an insulating spacer  16 . 
         [0030]    The differential contact  4  includes a first contact  41  and a second contact  42  separately fixed by the insulating stabilizer  3 . The differential contact  4  comprises a mounting portion  401  vertically extending out of a bottom side of the stabilizer  3  configured for connecting with the circuit board  500 , a mating portion  402  horizontally extending out of a front side of the stabilizer  3  configured for mating with the header  200 , and an intermediate portion  403  connecting the mounting portion  401  and the mating portion  402 . Both the first contact  41  and the second contact  42  are embedded into the insulating stabilizer  3  at the intermediate portion  403  and at least partially exposed to air from the intermediate portion  403 . 
         [0031]    The first contact  41  and the second contact  42  are positioned parallel with each other in a first distance Si and a second distance S 2  along the intermediate portion  403 . The first distance Si is smaller than the second distance S 2 . The second distance S 2  is smaller than the third distance S 3 . The second distance S 2  is smaller than the fourth distance S 4  too. The intermediate portion  403  has a front portion  432  adjacent to a front side of the insulating stabilizer  3 , and a lower portion  431  adjacent to a bottom side of the insulating stabilizer  3 . The front portion  432  has a third distance S 3  between the first contact  41  and the second contact. The lower portion  432  has a fourth distance S 4  between the first contact  41  and the second contact  42 . Both the third distance S 3  and the fourth distance S 4  are larger than the second distance S 2 . Preferablely, the fourth distance S 4  is larger than the third distance S 3 , due to the mouting portion  401  should to be stronger than the mating portion  402 . 
         [0032]    The conductive housing  120  further has a front edge  121 , a rear edge  124  apposing the front edge  121 , a top edge  122 , and a lower edge  123  apposing the top edge  122 . A flange  1242  is formed on the rear edge  124  adapted to assemble with the cutout  1121  of the retainer  11 . A flange  1242  is formed on the rear edge  124  adjacent to the top edge  122  adapted to assemble with the cutout  1122 . The top edge  122  has a flange  1221  received by the cutout  1110  of the retainer  11 , a covering portion  1222  extending out of the flange  1221  configured for covering the cutout  1110 , and a upper leading edge  1223  configured for leading the header  200 . The lower edge  123  has a number of slit  1231 , an extending portion  1230 , and a lower leading edge  1232  configured for leading the header  200 . Each grounding bridge  17  is mounted into the aligned slits  1231  after the frames  12  are stacked. 
         [0033]    The groove  1282  has a front notch  1281  adjacent to the front edge  121  comprising a pair of side walls  1286  and a bottom wall  1287 . A number of bulges  1291  extending out of the second side  129  of the conductive housing  120 . Each bulge  1291  is formed opposing to the front notch  1281  of the groove  1282 . The bulge  1291 extends into a front notch  1281  of another adjacent-stacked frame  12  configured for forming a mating room  160  therebetween. The bulge  1291  has a bezel  1292  configured for leading the shielding blades  230  when the receptacle connector  100  is mating with the header  200 . 
         [0034]    The insulating spacer  16  has a pair of receiving space  162  configured for receiving the mating portion  402  of each pair of the differential contact  4 . The insulating spacer  16  is mounted into the groove  1282  adjacent to the front side of the insulating stabilizer  3 . Each insulating spacer  16  has at least a rib  161  engaged with a slot  1285  defined on one of the side walls  1286  of the front notch  1281 . 
         [0035]    The conductive housing  120  further has a recess  1283  on the first side  128 . The recess  1283  defines at least a mounting hole  1284  thereon. The frame  12  further includes a shielding plate  15  mating with the recesses  1283 . The shielding plate  15  has at least a mounting leg  152  adapted to mate with the mounting hole  1284 . The mounting leg  152  forms a barb  1520  thereon configured for mating with the mounting hole  1284  tightly. The shielding plate  15  and the grooves  1282  of the conductive housing  120  define a number of shielding passages (not numbered) to shield each differential contacts  4 , such that the differential signal&#39;s cross talk reduced. 
         [0036]    Referring to  FIGS. 8 ,  9  and  10 A- 10 D, the insulating stabilizer  3  has a front portion  32  configured for embedding the front portion  432  of the differential contact  4 , a rear portion  31  configured for embedding the lower portion of the differential contact  4 , and a middle portion  33  connecting the first contact  41  and the second contact  42  over the intermediate portion  403 . The front portion  32  of the insulating stabilizer  3  has a front connective part  320  projecting between the first contact  41  and the second contact  42 . The rear portion  31  of the insulating stabilizer  3  has a rear connective part  310  projecting between the first contact  41  and the second contact  42 . The insulating stabilizer  3  further has a middle connective part  330  connecting the first contact  41  and the second contact  42  at the intermediate portion  403  under the second distance S 2 . All of the rear connective part  310 , front connective part  320  and middle connective part  330  are configured for strengthening the structure of the differential contact  4 . 
         [0037]    In order to improve the performance of the high speed signal transmission of the differential contact  4 , the thickness of the middle connective part  330  along the transverse direction is smaller than the rear connective part  310 , and smaller than the front connective part  320 . In another words, the cross section of the insulating stabilizer  3  along the transverse direction under the first distance  51  ( FIG. 10A ) is smaller than the cross section of the middle connective part  330  ( FIG. 10B ). The cross section of the middle connective part  330  along the transverse direction is smaller than the cross section of the rear connective part  310  ( FIG. 10D ) and the front connective part  320  ( FIG. 10C ). The cross section of the front connective part  320  along the transverse direction is smaller than the cross section of the rear connective part  310 . 
         [0038]    The middle connective part  330  is formed for keeping the distance between the first contact  41  and the second contact  42  (including the first distance S 1  and the second distance S 2 ), however, the thickness of the middle connective part  330  influences the impedance of the differential contact  4 . The middle connective part  330  could be changed into different configurations (see  FIG. 11A-11D ), so that the middle connective part  330  could keep impedance matched with the other part of the differential contact  4 . 
         [0039]    The first contact  41  and the second contact  42  are integrate punched from a metal plate (not shown) and kept in a planar shape. Each of the first contact  41  and the second contact  42  has an outer edge  404  opposing to each other and embedded into the stabilizer  3 , an inner edge  405  facing to each other, and two side edges  406  connecting the inner edge  405  and the outer edge  404 . The side edge  406  is partially exposed to air along the intermediate portion  403 . The differential contact  4  having a first distance S 1  between the inner edges  405  when each of the differential contact  4  has two side edges partially and the inner edge totally exposed to the air. The differential contact  4  has a second distance S 2  between the inner edges  405  when each of the differential contact  4  has one side edge  406  partially and the inner edge  405  totally exposed to the air. The differential contact  4  has a third distance S 3  between the inner edges  405  when each of the differential contact  4  only has one side edge  406  partially exposed to the air. As described before, the first distance S 1  is smaller than the second distance S 2 , and the second distance S 2  is smaller than the third distance S 3 . 
         [0040]    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.