Abstract:
A RJ modular connector ( 1 ) includes a housing ( 10 ) defining a plug receiving section, and a terminal core receiving section. A terminal core is ( 20 ) received in the terminal core receiving section and includes a number of terminals. A first and a second substrates ( 31, 41 ) are provided having a first and a second conductive traces thereon, respectively. The terminals are securely mounted onto the substrates. An electrical connection is established between a first and a second terminals and the first and second conductive traces, respectively, and portions of the conductive traces are arranged to create a first and a second electrical couplings between the first and a third terminals and the second and a fourth terminals. The third and the fourth terminals are arranged between the first and the second terminals and are located close to each other but far from the first and the second terminals, respectively.

Description:
[0001]    This is a continuation-in-part of the copending application Ser. No. 09/863,942 filed  
       on May 22, 2001. 
    
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention relates to a RJ modular connector, and more particularly to a RJ modular connector having a substrate provided therein to balance electrical couplings between terminals.  
           [0004]    2. Description of the Related Art  
           [0005]    RJ modular connector has been widely used in telecommunication system since it was firstly created. A so-called RJ45 modular connector has been widely used in the network system.  
           [0006]    The RJ45 modular connector includes a total of eight terminals. Resulting from miniaturization of the computer, all corresponding components, including connectors, have to be reduced for their dimension and size. One of the negative consequences or problem created from miniaturization is electrical coupling between terminals. When the RJ connector is used in low speed signal transmission, the couplings between adjacent terminals can be ignored in light of its effect. However, when the RJ connector is used for high speed signal transmission, the couplings between adjacent terminals create a great problem. Unless the electrical coupling can be effectively controlled within an accepted level, it is unlikely that the RJ 45 modular connector can be used in the high-speed signal transmission.  
           [0007]    One of the approaches is to select a pair of terminals as a differential pair. In the differential pair, two terminals transmit the same signal but with inverted phase. By this arrangement, the couplings coupled thereto can be finally subtracted in a data processing unit.  
           [0008]    As shown in an attached catalog from The Siemon Company, there are at least eight different patterns in selecting terminals as differential pair, i.e. T568A, T568B, USOC 4-pair, USOC 1-, 2- or 3-pair, 10BASE-T (802.3), Token Ring (802.5), 3-pair (MMJ), and TP-PMD (X3T9.5) and ATM. In each implementation, two terminals are selected as a pair in which some are close to each other, while some are apart from each other. Each pattern has its own uniqueness, while each also carries with it a coupling issue to be addressed.  
           [0009]    Among those patterns, T568A and T568B are widely used and in T568A, terminals 1, 2 configure 3 rd  pair, terminals 3, 6 configure 2 nd  pair, terminals 4, 5 configure 1 st  pair while terminals 7, 8 configure 4 th  pair. In T568B, terminals 1, 2 configure 2 nd  pair, terminals 3, 6 configure 3 rd  pair, terminals 4, 5 configure 1 st  pair, while terminals 7, 8 configure 4 th  pair.  
           [0010]    Since those eight terminals are equally spaced, electrical couplings between terminals will surely create some problems, i.e. coupling or cross-talk. For example, if we take terminal 3 into consideration, terminal 3 will naturally pick up energy coupled from terminals 2 and 4 which are close to terminal 3. On the other hand, terminal 6, which carries signal having inverted phase of the signal carried by terminal 3, will also pick up energy coupled from terminals 5 and 7. However, energy coupled into terminals 3, 6 from terminals 2 and 7 can not be suitably eliminated because terminals 3, 6 is unlikely to establish couplings between terminal 1 and terminal 8 to balance the couplings between terminals 2, 3 and 6, 7. Accordingly, signals transmitted by terminals 3, 6 carry noises generated by their adjacent terminals 2, 7. In addition, terminals 3 and 6 will also carry noises coupled thereto from terminals 4, 5 and which couplings should be also carefully taken care of in order to avoid certain noises.  
           [0011]    In order to decrease the effects of electrical coupling between the (3 rd , 4 th ) and (3 rd , 2 nd ) terminals, and (6 th , 5 th ) and (6 th , 7 th ) terminals, many approaches have been provided, such as creating electrical couplings between 3 rd  and 1 st  terminals and 3 rd  and 5 th  terminals to balance the electrical coupling between the 3 rd  and 2 nd  terminals and 3 rd  and 4 th  terminals, and creating electrical coupling between 6 th  and 8 th  terminals and 6 th  and 4 th  terminals to balance the electrical couplings between the 6 th  and 7 th  terminals and 6 th  and 5 th  terminals.  
           [0012]    However, as mentioned above, those eight terminals are arranged in a common plane, it is impossible to create those balancing electrical couplings, i.e. (1 st , 3 rd ), (3 rd , 5 th ), and (4 th , 6 th ), (6 th , 8 th ) terminals when all terminals are located in the same level, it is unlikely to create any electrical channels therebetween to create those electrical couplings accordingly.  
           [0013]    The Siemon Company, a US company, discloses a solution posted on the Internet, http://www.siemon.com/white_papers/99-08-30-through-hole.asp. A hard copy thereof is herein attached for reference.  
           [0014]    As clearly shown in FIG. 4 of that reference, 6 th  and 2 nd  terminals are arranged in the first layer, while 8 th , 5 th , 4 th , and 1 st  terminals are arranged in the second layer, and 7 th  and 3 rd  terminals are arranged in the third layer.  
           [0015]    The 6 th  terminal in the first layer has a rectangular loop having its longitudinal sides aligned with terminals 4 th  and 8 th  located in the second layer, while terminal 3 in the third layer also has a rectangular loop having its longitudinal sides aligned with terminals 5 th  and 1 st  located in the second layer.  
           [0016]    In addition, the right longitudinal loop side of the terminal 6 th  further includes a square corresponding to a square formed in terminal 4 th . The left longitudinal loop side of the terminal 3 includes also a square with respect to the square formed on terminal 8 th .  
           [0017]    Arrangements suggested by Siemon are to increase the couplings between (1 st , 3 rd ), (3 rd , 5 th ), and (4 th , 6 th ), (6 th , 8 th ) terminals thereby helping to balance electrical couplings of the terminals.  
           [0018]    However, those eight or four set sets of terminals are arranged in three different layers, and each set of terminals are separately divided by an insulative sheet material. This will no doubt increase the complexity of the connector.  
           [0019]    In addition, there are five different shapes and configurations among those eight terminals. Each terminal has its own shape which is different from each other, especially the 3 rd  and 6 th  terminals, each including the rectangular loop portion which overlaps corresponding terminals to create desired electrical couplings. Each loop further forms the square to increase the electrical couplings with corresponding terminals having the square. The electrical couplings created can help to meet higher system requirement. The eight different configuration of the terminals will surely increase the difficulty and complexity in production.  
           [0020]    There are some other approaches, including routing terminal tails of those 3 rd , 6 th  and 4 th , 5 th  terminals to alter their position and affect couplings between 3 rd , 2 nd  and 3 rd , 4 th ; and 6 th , 5 th , and 6 th , 7 th  terminals. However routing terminal tails will inevitably increase the manufacturing cost.  
           [0021]    U.S. Pat. No. 6,120,329, issued to Steinman on Sep. 19, 2000, discloses another approach to solve the above-addressed problem. Again, terminals are configured with different shapes and dimensions making the production complex.  
           [0022]    U.S. Pat. No. 5,069,641 issued to Sakamoto et al. discloses a suggestion of using printed circuit board in the RJ modular housing, however, it addresses different issues.  
         SUMMARY OF THE INVENTION  
         [0023]    It is an object of this invention to provide an RJ modular connector, and more particularly to an RJ modular connector having a substrate with conductive traces provided therein to balance electrical couplings between terminals.  
           [0024]    It is still an object of this invention to provide a RJ modular connector which can be easily manufactured.  
           [0025]    In order to achieve the objective set forth, an RJ modular connector in accordance with the present invention comprises a housing defining a plug receiving section, and a terminal core receiving section. A terminal core is received in the terminal core receiving section and includes a plurality of terminals. A first and a second substrates are provided having first and second conductive traces thereon, respectively. The terminals are securely mounted onto the substrates. A first and a second electrical connections are established between a first and a second terminals and the first and second conductive traces, and a portion of each conductive trace is arranged to create a first and a second electrical couplings between the first and second terminals and a third and a fourth terminals, respectively. The third and the fourth terminals are arranged between the first and the second terminals and configure a differential pair located far from the first and the second terminals.  
           [0026]    Other objects and further features of the present invention will be apparent from the following detailed description when read in conjunction with the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0027]    [0027]FIG. 1A is a perspective view of a RJ modular connector in accordance with the present invention;  
         [0028]    [0028]FIG. 1B is a front view of FIG. 1A;  
         [0029]    [0029]FIG. 1C is similar to FIG. 1A except viewed from a reverse direction;  
         [0030]    [0030]FIG. 1D is a front view of FIG. 1C;  
         [0031]    [0031]FIG. 1E is an exploded view of FIG. 1C;  
         [0032]    [0032]FIG. 2A is a bottom view of a top substrate;  
         [0033]    [0033]FIG. 2B is a top view of FIG. 2A;  
         [0034]    [0034]FIG. 2C is a top view of a lower substrate;  
         [0035]    [0035]FIG. 2D is a bottom view of FIG. 2C;  
         [0036]    [0036]FIG. 3A is an exploded view of a terminal core in accordance with the present invention;  
         [0037]    [0037]FIG. 3B is similar to FIG. 3A with terminals attached to the lower substrate;  
         [0038]    [0038]FIG. 3C is an assembled perspective view of the terminal core;  
         [0039]    [0039]FIG. 3D is another perspective view of the terminal core;  
         [0040]    [0040]FIG. 3E is a cross sectional view of the terminal core; and  
         [0041]    [0041]FIG. 3F is an exploded view of the terminal core with carrier attached thereto. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0042]    Referring to FIGS. 1A to  1 E, a RJ modular connector  1  in accordance with the present invention includes a housing  10  defining a plug receiving space  11 , and a terminal core receiving space  12  in which a modular terminal core  20  securely attached therein. The RJ modular connector  1  has a general dimension and shape corresponding to existing industry specifications. Accordingly, no details are given thereto. The unique feature of the present invention resides on providing the modular terminal core  20  which can be simply made in a cost-effective manner. In addition, the modular terminal core  20  is arranged such that electrical couplings can be created between selected terminals to balance electrical couplings between selected terminals. By this arrangement, cross-talk between certain terminals can be effectively eliminated or reduced.  
         [0043]    Referring to FIGS. 2A to  2 D in conjunction with FIGS. 3A to  3 F, the terminal core  20  in accordance with the present invention includes a plurality of terminals  21 ,  22 ,  23 ,  24 ,  25 ,  26 ,  27 , and  28  and lower and upper or first and second printed circuit boards  31  and  41 . The terminals  21 ,  22 ,  23 ,  24 ,  25 ,  27  and  28  respectively have contacting portions  21   b ,  22   b ,  23   b ,  24   b ,  25   b ,  26   b ,  27   b , and  28   b  extending into the plug receiving space  11 , leg portions  21   c ,  22   c ,  23   c ,  24   c ,  25   c ,  26   c ,  27   c  and  28   c  extending away from the housing  10 , and connecting portions  21   a ,  22   a ,  23   a ,  24   a ,  25   a ,  26   a ,  27   a  and  28   a  connecting the contacting and leg portions  21   b ,  22   b ,  23   b ,  24   b ,  25   b ,  26   b ,  27   b , and  28   b  and  21   c ,  22   c ,  23   c ,  24   c ,  25   c ,  26   c ,  27   c  and  28   c  and being sandwiched in a common plane between the lower and upper printed circuit boards  31 ,  41 . Among the terminals, terminals  21 ,  22  configures a first pair, terminals  23 ,  26  configures a second pair, terminals  24 ,  25  configures a third pair, while terminals  27 ,  28  configures a fourth pair. The contacting portions  21   b ,  22   b ,  23   b ,  24   b ,  25   b ,  26   b ,  27   b , and  28   b  are so formed as to be equally spaced from each other and the leg portions  21   c ,  22   c ,  23   c ,  24   c ,  25   c ,  26   c ,  27   c  and  28   c  are so configured as also to be equally spaced from each other, while the connecting portions  21   a ,  22   a ,  23   a ,  24   a ,  25   a ,  26   a ,  27   a  and  28   a  are differently configured so that the connecting portions  23   a ,  26   a  are located a little far from the adjacent connecting portions  22   a  and  24   a ,  25   a  and  27   a  whereby the terminal pairs  21   a  and  22   a ,  24   a  and  25   a , and  27   a  and  28   a  are respectively closely arranged with respect to each other, thereby enhancing energy couplings and decreasing cross talk therebetween. In other words, in the present invention, the distance between the two connecting portions  21   a  and  22   a , or  24   a  and  25   a , or  27   a  and  28   a , in the differential pair of the terminals  21  and  22 , or  24  and  25 , or  27  and  28 , is smaller than the distance between the two connecting portions  22   a  and  23   a ,  23   a  and  24   a ,  25   a  and  26   a ,  26   a  and  27   a.    
         [0044]    The lower printed circuit board  31  defines first (top) and second (bottom) surfaces  31   a ,  31   b  and with conductive footprints or conductive pads  321 ,  322 ,  323 ,  324 ,  325 ,  326 ,  327  and  328  formed on the first face  31   a . A conductive loop  33  is formed on the second face  31   b  and surrounded by a grounding plane  34 . The conductive loop  33  is electrically connected to the conductive footprints  323  by means of tunnels  33   a . Since the tunnel  33   a  is configured by a through-hole coated with conductive material, such as solder, and is known to the skill in the art, no details are given herebelow.  
         [0045]    The upper printed circuit board  41  defines first (top) and second (bottom) surfaces  41   a ,  41   b  and with conductive footprints or conductive pads  421 ,  422 ,  423 ,  424 ,  425 ,  426 ,  427  and  428  formed on the second face  41   b . A conductive loop  43  is formed on the first face  41   a  and surrounded by a grounding plane  44 . The conductive loop  43  is electrically connected to the conductive footprints  426  by means of tunnels  43   a  which is identical to the tunnels  33   a.    
         [0046]    Among the footprints  321 ,  322 ,  323 ,  324 ,  325 ,  326 ,  327  and  328 , the footprint  323  corresponding to terminal  23  includes first and second portions  323   a ,  323   b ; while footprint  326  with respect to terminal  26  includes also first and second portions  326   a ,  326   b . Among the footprints  421 ,  422 ,  423 ,  424 ,  425 ,  426 ,  427  and  428 , the footprint  426  with respect to the terminal  26  includes first and second portions  426   a ,  426   b ; while footprint  423  with respect to the terminal  23  includes also first and second portions  423   a ,  423   b.    
         [0047]    The connecting portions  21   a ,  22   a ,  23   a ,  24   a ,  25   a ,  26   a ,  27   a , and  28   a  of the terminals  21 ,  22 ,  23 ,  24 ,  25 ,  26 ,  27 , and  28  can be securely sandwiched between the printed circuit boards  31 ,  41  by applying solder pastes on the footprints  321 ,  322 ,  323 ,  324 ,  325 ,  326 ,  327  and  328  and the footprints  421 ,  422 ,  423 ,  424 ,  425 ,  426 ,  427  and  428 , and then reflowing the solder pastes such that the terminals  21 ,  22 ,  23 ,  24 ,  25 ,  26 ,  27 , and  28  are completely and securely attached to the footprints  321 ,  322 ,  323 ,  324 ,  325 ,  326 ,  327  and  328  of the lower printed circuit board  31 ; and footprints  421 ,  422 ,  423 ,  424 ,  425 ,  426 ,  427  and  428  of the upper printed circuit board  41 .  
         [0048]    As clearly shown in FIGS. 2B, 2D and  3 E, the conductive trace  33  formed on the bottom (second) face of the first substrate  31  includes first and second portions  33   b ,  33   c  which are aligned with terminals  21  and  25 , while the conductive trace  43  formed on upper (first) face of the substrate  41  includes first and second portions  43   b ,  43   c  which are aligned with terminals  24  and  28 . Accordingly, electrical couplings will be generated between the first portion  33   b  and the terminal  21 , and the second portion  33   c  and the terminal  25 . By the same reason, electrical couplings will be generated between the first portion  43   b  and the terminal  24 , and the second portion  43   c  and the terminal  28 . On the other hand, since the connecting portions  23   a  and  26   a  are respectively located far from the connecting portions  24   a  and  25   a , the second portion  33   c  and the first portion  43   b  would add little influence on signal transmission of the terminals  26  and  23 . However, if the connecting portions  21   a ,  22   a ,  23 ,  24   a ,  25   a ,  26   a ,  27   a  and  28   a  are equally spaced from each other, due to the closeness therebetween, the second portion  33   c  and the first portion  43   b , while as desired are coupled to the terminals  25  and  24 , respectively, are more or less coupled unwantedly to the terminals  26  and  23 , which adversely affects couplings between the terminals  23  and  26  and increases cross talk therebetween.  
         [0049]    As can be readily appreciated, the electrical coupling between the third terminal  23  and the first terminal  21  by means of the conductive trace  33  (via first portion  33   b ) will properly help to balance the electrical coupling between the third terminal  23  and the second terminal  22 . While, the electrical coupling between the sixth terminal  26  and the eighth terminal  28  by means of the conductive trace  43  (via second portion  43   c ) will also properly help to balance the electrical coupling between the sixth terminal  26  and the seventh terminal  27 . As a result, the energy coupled into terminals  23 ,  26  from terminals  22 ,  27  can be more properly balanced by the introduction of the electrical couplings between the terminals  23 ,  26  with respect to the terminals  21  and  28 , respectively. As a result, the signal transmitted through the differential pair terminals  23 ,  26  benefits from balanced coupling from its adjacent terminals, such as terminals  22  and  27 . Furthermore, due to the unique arrangement of the connecting portions  21   a ,  22   a ,  23   a ,  24   a ,  25   a ,  26   a ,  27   a , and  28   a , the terminals  21  and  22 ,  24  and  25 ,  27  and  28  in each differential pair are more closely located than when the eight terminals as usually are equally spaced from one another, thereby enhancing coupling and decreasing cross talk therebetween. As to the differential pair of the terminals  23  and  26 , since they are located relatively fartherly from adjacent terminals  22 ,  24 ,  25  and  27  and in turn are located fartherly from the second portion  33   c  and the first portion  43   b  of the conductive traces  33  and  43  than those conventional equally spaced terminals, they are minimally affected by adjacent terminals and the conductive traces and the coupling between them are ensured, thereby guaranteeing high speed signal transmission in the two terminals  23 ,  26 .  
         [0050]    As can be readily seen from FIG. 3F, the manufacturing of the terminal core  20  is comparatively simple as compared to the prior art in which the terminals  21  to  28  are integrally molded or assembled together. In the present invention, the terminals  21  to  28  can be simply stamped from a sheet metal  70 . Then the terminals  21  to  28  can be easily sandwiched by the first and second substrate  31 ,  41 . The carrier  70   a  can be simply trimmed off after the terminals  21  to  28  are securely attached and sandwiched between the first and second substrates  31  and  41 .  
         [0051]    In addition, it can be readily appreciated that during the stamping of the terminals  21  to  28 , retaining beam  29  having barbs  29   a  can be also formed on the sheet metal  70  and which are also attached and sandwiched between the first and second substrates  31  and  41  by solder. Accordingly, the terminal core  20  resulted therefrom can be easily inserted into the terminal core receiving space  11  and securely attached therein by the barbs  29   a.    
         [0052]    Even the above embodiment uses patterns of T568A and T568B to illustrate the spirit of the present invention, it can be readily appreciated that coupling issues from other patterns, such as 3-Pair MMJ, USOC 4-pair, and TP-PMD (X3T9.5) and ATM can also be helped out by the teaching of the present invention without creating complex configuration of the terminals. By the teaching of the present invention, the terminals can be made as simple as existing terminals, while the coupling issue can be taken care by the printed circuit board.  
         [0053]    Even the present invention illustrates its best mode of embodiments by establishing electrical couplings between conductive loops and corresponding terminals, it can be readily appreciated that the electrical couplings can be also created via conductive loops and conductive pads on which terminals are electrically connected thereto, i.e. terminal heads and tails are connected to the conductive pads extending through a substrate, while the conductive loop and the conductive pads are arranged to create electrical coupling to balance electrical couplings among terminals.  
         [0054]    It will be understood that the invention may be embodied in other specific forms without departing from the spirit or central characteristics thereof. The present examples and embodiments, therefore, are to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details given herein.