Abstract:
A RJ modular connector ( 1 ) comprises a housing ( 10 ) defining a plug receiving section ( 11 ) and a terminal insert receiving section ( 12 ). A terminal insert ( 20 ) includes a plurality of terminals ( 21, 22, 23, 24, 25, 26, 27, 28 ) and a pair of grounding terminals ( 30 ) beside the plurality of terminals. An electrical connection is established between the grounding terminals and grounding traces ( 351, 371, 381, 391, 451, 471, 481, 491 ) defined between selected pairs of signal terminals through a grounding layer ( 31   b,    41   a ) and a pair of ground pads ( 329, 429 ) defined on a printed circuit board.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of commonly assigned U.S. patent application Ser. No. 09/863,942, filed May 22, 2001 is now U.S. Pat. No. 6,413,121. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     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 and having at least one grounding terminal to eliminate noises. 
     2. Description of the Prior Art 
     A 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. 
     The RJ45 modular connector includes totally eight terminals. Resulted 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 problems resulted from miniaturization is electrical couplings between terminals. Unless the electrical coupling can be effectively controlled within an accepted level, it is unlikely that the RJ45 modular connector can be used in the high-speed signal transmission. 
     As mentioned above, there are totally eight terminals within the RJ45 connector. There are two different approaches for configuring terminal pair. In the first approach, terminals  1 ,  2  configure the 3rd pair, terminals  3 ,  6  configure the 2nd pair, terminals  4 ,  5  configure the 1st pair, and terminals  7 ,  8  configure the 4th pair. In the second approach, terminals  1 ,  2  configure the 2nd pair, terminals  3 ,  6  configure the 3rd pair, terminals  4 ,  5  configure the 1st pair, and terminals  7 ,  8  configure the 4th pair. 
     The benefit for selecting two terminals as a differential pair, carrying the same signal but with different phases, is if both terminals are affected by the same amount of noise, these noises can be subtracted when both signals arrive at their destination. 
     Since those eight terminals are equally spaced, electrical coupling 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 be imposed with energy from terminals  2  and  4  which are closer to terminal  3 . On the other hand, terminal  6 , which carries signal having an inverted phase of the signal carried by terminal  3 , will also be imposed with energy from terminals  5  and  7 . The energy imposed to terminals  3 ,  6  from respective terminals  4 ,  5  can be ultimately eliminated because terminals  4 ,  5  carry the same, but inverted signals. However, energy imposed to terminals  3 ,  6  from respective terminals  2  and  7  can not be suitably eliminated because terminals  3 ,  6  is unlikely to establish couplings between terminals  1 ,  3  and terminals  6 ,  8  to balance the couplings between terminals  2 ,  3  and  6 ,  7 . Accordingly, signals transmitted by terminals  3 ,  6  carry noises resulted from their adjacent terminals  2 ,  7 . 
     In order to decrease the unwanted electrical coupling between the (3rd, 4th) and (3rd, 2nd) terminals, and (6th, 5th) and (6th, 7th) terminals, many approaches have been provided, such as creating an electrical coupling between 3rd and 1st terminals to balance the unwanted electrical coupling between the 3rd and 2nd, and creating electrical coupling between 6th and 8th terminals to balance the unwanted electrical coupling between the 6th and 7th terminals. 
     However, as mentioned above, since those eight terminals are arranged in a common plane, it is impossible to create those balancing electrical couplings, i.e. (1st, 3rd), (3rd, 5th), and (4th, 6th), (6th, 8th) terminals and it is unlikely to create any electrical channels therebetween to create those positive electrical couplings accordingly. 
     The Siemon Company, a US company, discloses a solution posted on the Internet. A hard copy thereof is herein attached for reference. 
     As clearly shown in FIG. 4 of that reference, the 6th and 2nd terminals are arranged in the first layer, the 8th, 5th, 4th, and 1st terminals are arranged in the second layer, and the 7th and 3rd terminals are arranged in the third layer. 
     The 6th terminal in the first layer has a rectangular loop having its longitudinal sides aligned with terminals 4th and 8th located in the second layer, while the 3rd terminal in the third layer also has a rectangular loop having its longitudinal sides aligned with 5th and 1st terminals located in the second layer. 
     In addition, the right longitudinal loop side of the 6th terminal further includes a square corresponding to a square formed on the 4th terminal. The left longitudinal loop side of the 3rd terminal also includes a square corresponding to a square formed on the 8th terminal. 
     All arrangements suggested by Siemon are to increase the couplings between (1st, 3rd), (3rd, 5th), and (4th, 6th), (6th, 8th) terminals thereby reducing electrical couplings of the 3rd and 6th terminals corresponding to their adjacent terminals (2nd, 4th) and (5th, 7th) respectively. By this arrangement, it is assumed that the noises imposed on terminals  3 ,  6  from respectively terminals  2 ,  7  can be adequately balanced by couplings between terminals  3 ,  1 , and terminals  6 ,  8 . 
     However, those three sets of terminals are arranged in three different layers, and an insulative material separates either of two adjacent sets of terminals. This will no doubt increase the complexity of the connector. 
     In addition, there are eight different shapes and configurations among those eight terminals. Each terminal has its own shape which is different from other, especially to the 3rd and 6th terminals, each including the rectangular loop portion which overlaps corresponding terminals to create wanted electrical couplings. Each loop further forms the square to increase the electrical couplings with corresponding terminals having the square. Even the electrical couplings can be created according to the requirement, those eight different configurations of the terminals will surely increase the difficulty and complexity in production. 
     On the other hand, it has not provided a grounding plane for grounding protections because the eight terminals are insert molded with the terminal material. When the terminals transmit signals, the crosstalk and the electromagnetic interfere (EMI) often happen. Since there is no grounding plane, the integrity of signals is not ensured. 
     Hence, an improved RJ modular connector is desired to overcome the disadvantages of the prior art connector. 
     SUMMARY OF THE INVENTION 
     It is an object of this invention to provide a RJ modular connector, and more particularly to a RJ modular connector having a substrate with conductive traces provided thereon to balance electrical couplings between terminals. 
     It is another object of this invention to provide a RJ modular connector, and more particularly to a RJ modular connector having a pair of grounding terminals to eliminate noise. 
     It is yet another object of this invention to provide a RJ modular connector which can be easily manufactured and assembled. 
     In order to achieve the objects set forth, a RJ modular connector in accordance with the present invention comprises a housing defining a plug receiving section and a terminal insert receiving section. A terminal insert is received in the terminal insert receiving section and includes a plurality of terminals and a pair of grounding terminals beside the plurality of terminals. A substrate provides conductive traces, a plurality of grounding traces, a grounding layer and a pair of ground pads thereon. The terminals are securely mounted onto the substrate. An electrical connection is established between one of the grounding terminals and the grounding traces for reducing the noise through the grounding layer and the ground pad. 
     Other objects, advantages and novel features of the invention will become more apparent from the following detailed description of the present embodiment when taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1A is a perspective view of a RJ modular connector in accordance with the present invention; 
     FIG. 1B is a front view of FIG. 1A; 
     FIG. 1C is similar to FIG. 1A but viewed from a reverse direction; 
     FIG. 1D is a front view of FIG. 1C; 
     FIG. 1E is an exploded view of FIG. 1C; 
     FIG. 2A is a bottom view of a top substrate; 
     FIG. 2B is a top view of the top substrate shown in FIG. 2A; 
     FIG. 2C is a top view of a bottom substrate; 
     FIG. 2D is a bottom view of the bottom substrate shown in FIG. 2C; 
     FIG. 3A is an exploded view of a terminal insert in accordance with the present invention; 
     FIG. 3B is similar to FIG. 3A but with terminals attached to the bottom substrate; 
     FIG. 3C is an assembled view of FIG. 3A; 
     FIG. 3D is an assembled view of FIG. 3A but taken from a reverse direction of FIG. 3C; 
     FIG. 3E is a cross sectional view taken along line  3   e - 3   e  of FIG. 3C; and 
     FIG. 3F is an exploded view of the terminal insert with a carrier attached thereto. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     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 section  11 , and a terminal insert receiving section  12  in which a modular terminal insert  20  securely attached therein and with contacting portions  21   b,    22   b,    23   b,    24   b,    25   b,    26   b,    27   b  and  28   b  extending into the plug receiving section  11 , while leg portions  21   c,    22   c,    23   c,    24   c,    25   c,    26   c,    27   c,    28   c  extending away from the housing  10  and a pair of grounding terminals  30  on opposite sides of the eight leg portions. 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 in providing the modular terminal insert  20  which can be easily manufactured and assembled in a cost-effective manner. In addition, the modular terminal insert  20  is arranged in such a manner that positive electrical couplings can be created between selected terminals to balance negative electrical couplings between selected terminals. By this arrangement, cross talk between certain terminals can be effectively eliminated or reduced. 
     Referring to FIGS. 2A to  2 D in conjunction with FIGS. 3A to  3 F, the terminal insert  20  in accordance with the present invention includes a plurality of terminals  21 ,  22 ,  23 ,  24 ,  25 ,  26 ,  27 , and  28  sandwiched between lower and upper printed circuit boards  31  and  41 . Among the terminals, terminals  21 ,  22  configure a first pair, terminals  23 ,  26  configure a second pair, terminals  24 ,  25  configure a third pair, and terminals  27 ,  28  configure a fourth pair. 
     Referring to FIGS. 2C and 2D, the lower printed circuit board  31  defines first and second faces  31   a,    31   b  and with conductive footprints  321 ,  322 ,  323   a,    323   b,    324 ,  325 ,  326   a,    326   b,    327  and  328  and a pair of ground pads  329  formed on the first face  31   a.  The second face  31   b  is a grounding surface. A conductive trace  33  is rectangular and formed on the second face  31   b.  The conductive trace  33  is electrically connected to the conductive footprints  326  by means of vias  33   a.  Since the via  33   a  is formed by a through-hole coated with conductive material, such as solder, and is known to one of ordinary skill in the art, no details are given herein. In addition, the lower printed circuit board  31  also defines a plurality of vias  35 ,  36 ,  37 ,  38 ,  39 . The vias  35 ,  37 ,  38 ,  39  have conductive materials therein and respectively connect with a narrow grounding trace  351 ,  371 ,  381 ,  391 . These narrow grounding traces are respectively defined between the footprints of the lower printed circuit board  31  and can connect with the second face  31   b  through the vias  35 ,  37 ,  38 ,  39 . 
     Referring to FIGS. 2A and 2B, the upper printed circuit board  41  defines first and second faces  41   a,    41   b  and with conductive footprints  421 ,  422 ,  423   a,    423   b,    424 ,  425 ,  426   a,    426   b,    427  and  428  and a pair of ground pads  429  formed on the second face  41   b.  The first face  41   a  is a grounding surface. A conductive trace  43  is rectangular and formed on the first face  41   a.  The conductive trace  43  is electrically connected to the conductive footprints  423   a,    423   b  by means of vias  43   a  which is identical to the vias  33   a.  In addition, the upper printed circuit board  41  also defines a plurality of vias  45 ,  46 ,  47 ,  48 ,  49  and a plurality of narrow grounding traces  451 ,  471 ,  481 ,  491  which are identical to those of the lower printed circuit board  31 . 
     Among the footprints  321 ,  322 ,  323   a,    323   b,    324 ,  325 ,  326   a,    326   b,    327  and  328 , the footprint corresponding to terminal  23  includes first and second portions  323   a,    323   b;  while the footprint corresponding to terminal  26  also includes first and second portions  326   a,    326   b.  Among the footprints  421 ,  422 ,  423   a,    423   b,    424 ,  425 ,  426   a,    426   b,    427  and  428 , the footprint corresponding to the terminal  26  includes first and second portions  426   a,    426   b;  while the footprint corresponding to the terminal  23  also includes first and second portions  423   a,    423   b.    
     As shown in FIGS. 3A-3D, 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   a,    323   b,    324 ,  325 ,  326   a,    326   b,    327 ,  328  and footprints  421 ,  422 ,  423   a,    423   b,    424 ,  425 ,  426   a,    426   b,    427 ,  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   a,    323   b,    324 ,  325 ,  326   a,    326   b,    327 ,  328  of the lower printed circuit board  31  and footprints  421 ,  422 ,  423   a,    423   b,    424 ,  425 ,  426   a,    426   b,    427 ,  428  of the upper printed circuit board  41 . 
     As clearly shown in FIGS. 2B,  2 D and  3 E, the conductive trace  33  formed on the second face  31   b  of the lower printed circuit board  31  includes first and second portions  33   b  and  33   c  which are respectively aligned with terminals  28  and  24 , while the conductive trace  43  formed on the first face  41   a  of the upper printed circuit board  41  includes first and second portions  43   b  and  43   c  which are respectively aligned with terminals  25  and  21 . Accordingly, electrical couplings will be generated between the first portion  33   b  and the terminal  28 , and the second portion  33   c  and the terminal  24 . By the same reason, electrical couplings will be generated between the first portion  43   b  and the terminal  25 , and the second portion  43   c  and the terminal  21 . 
     As it can be readily appreciated that, the electrical coupling between the third terminal  23  and the first terminal  21  by means of the conductive trace  43  (via first portion  43   c ) will 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  33  (via second portion  33   b ) will help to balance the electrical coupling between the sixth terminal  26  and the seventh terminal  27 . As a result, the energy imposed on terminals  23 ,  26  by respectively terminals  22 ,  27  can be more balanced by the introduction of the electrical couplings between the terminals  23 ,  26  and terminals  21 ,  28 , respectively. 
     As it can be readily seen from FIG. 3F, the manufacturing of the terminal insert  20  is comparatively simple as compared to the prior art in which the terminals are integrally molded 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 printed circuit boards  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 printed circuit boards  31  and  41 . 
     In addition, it can be readily appreciated that, during the stamping process of the terminals  21  to  28 , a pair of retaining beam  29  having barbs  29   a  can also be formed on the sheet metal  70 . The retaining beams  29  can be securely sandwiched between the printed circuit boards  31 ,  41  by applying solder pastes on the ground pads  329  and  429 , and then reflowing the solder pastes such that the retaining beams  29  are completely and securely attached to the ground pads  329  of the lower printed circuit board  31  and ground pads  429  of the upper printed circuit board  41 . Accordingly, the terminal insert  20  resulted therefrom can be easily inserted into the terminal insert receiving section  12  and securely retained therein by the barbs  29   a.  A pair of grounding terminals  30  is respectively connected with the retaining beams  29  (referring to FIGS. 3A to  3 D) for being connected to the grounding traces of a motherboard on which the RJ modular connector  1  is mounted. When the noise among the terminals happens, the narrow grounding traces  351 ,  371 ,  381 ,  391 ,  451 ,  471 ,  481 ,  491  respectively defined between the footprints can ground the noise to the grounding layer  31   b,    41   a  through the vias  35 ,  37 ,  38 ,  39 ,  45 ,  47 ,  48 ,  49 . Then, the grounding layer grounds the noise to the ground pads  329 ,  429  through the vias  36 ,  46 . Finally, the noise is grounded to the grounding traces of the motherboard via the grounding terminals  30 . In light of this, all terminals are more or less covered by ground path such that the noise and cross talks can be reduced. Furthermore, using the retaining beams  29  connected with the grounding terminals  30  to attach the printed circuit board  31  and  41  to the housing  10  can increase the bonding between the upper and lower boards  31 ,  41 . 
     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.