Abstract:
An electrical connector of the present invention includes an insulative housing ( 10 ) and a contact insert ( 12 ) attached to the housing. The contact insert includes eight singnal contacts ( 26   a-   26   h ) and two grounding contacts ( 28   a,    28   b ) arranged side by side and an upper printed substrate ( 30 ) and a lower printed substrate ( 32 ) sandwiching the singnal contacts and the grounding contacts therebetween. Two selected singnal contacts ( 26   c,    26   f ) each are severed into three pieces but the other contacts ( 26   a,    26   b,    26   d,    26   e,    26   g,  and  26   h ) are not severed. Two end portions ( 58   a,    58   b;    56   a,    56   b ) of the severed contacts are re-routed by conductive traces on the upper lower printed substrates, while the middle portions ( 58   c,    56   c ) are grounded. Therefore, lengths inducing electrical capacitances between the severed contacts and the adjacent contacts can be reasonably reduced, thereby reducing crosstalk between the severed contacts and the adjacent contacts.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application is a Continuation-In-Part (CIP) application of co-pending application Ser. No. 09/863,942, filed on May 22, 2001. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an RJ modular connector, and more particularly to an RJ modular connector having a printed circuit board (PCB) provided therein to reduce crosstalk between terminals. 
     2. Description of Related Art 
     RJ modular connector has been widely used in telecommunication system since it was firstly created. A so-called RJ45 modular connector is a typical example for this kind of connector. 
     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 as to their dimension and size. One of the negative consequences or problems created from miniaturization is crosstalk between terminals. When the RJ connector is used in low speed signal transmission, the crosstalk between adjacent terminals can be ignored in light of its effect. However, when the RJ connector is used for high-speed signal transmission, the crosstalk between adjacent terminals creates a great problem. Unless the crosstalk 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. 
     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 of opposite polarity. By this arrangement, a majority of the noise received between the two terminals of a differential pair can be subtracted in a data processing unit. 
     There are at least eight different standards having reference in selecting terminals as differential pairs namely 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 a crosstalk issue that needs to be solved. 
     Among those standards, T568A and T568B are widely used and in T568A, terminals  1 ,  2  configure 3rd pair, terminals  3 ,  6  configure 2nd pair, terminals  4 ,  5  configure 1st pair, while terminals  7 ,  8  configure 4th pair. In T568B, terminals  1 ,  2  configure 2nd pair, terminals  3 ,  6  configure 3rd pair, terminals  4 ,  5  configure 1st pair, while terminals  7 ,  8  configure 4th pair. 
     Since those eight terminals are equally spaced, electrical capacitances between terminals will surely create some problems, i.e. crosstalk. For example, terminal  3  will naturally pick up energy induced 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 induced from terminals  5  and  7 . However, energy induced into terminals  3 ,  6  from terminals  2  and  7  can not be suitably eliminated because terminals  3 ,  6  is unlikely to establish equal capacitances between terminal  1  and terminal  8  to balance the capacitances 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 induced thereto from terminals  4 ,  5  and which capacitances should be also carefully taken to avoid certain noises. 
     In order to decrease the effects of electrical capacitance between the (3rd, 4th) and (3rd, 2nd) terminals, and (6th, 5th) and (6th, 7th) terminals, many approaches have been provided, such as creating electrical capacitances between 3rd and 1st terminals and 3rd and 5th terminals, to balance the electrical capacitance between the 3rd and 2nd terminals and 3rd and 4th terminals, and creating electrical capacitance between 6th and 8th terminals and 6th and 4th terminals to balance the electrical capacitances between the 6th and 7th terminals and 6th and 5th terminals. 
     To solve the above issue, the terminals should be rearranged or new electrical capacitances should be added. 
     one known solution is to have 6th and 2nd terminals arranged in the first layer, while 8th, 5th, 4th, and 1st terminals are arranged in the second layer, and 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 terminal  3  in the third layer also has a rectangular loop having its longitudinal sides aligned with terminals 5th and 1st located in the second layer. 
     In addition, the right longitudinal loop side of the terminal 6th further includes a square corresponding to a square formed in terminal 4th. The left longitudinal loop side of the terminal  3  includes also a square with respect to the square formed on terminal 5th. 
     The above arrangements are to increase the capacitances between (1st, 3rd), (3rd, 5th), and (4th, 6th), (6th, 8th) terminals thereby helping to balance electrical capacitances of the terminals. 
     However, those eight or four sets of terminals are arranged in three different layers, and each set of terminals are separately divided by an insulative sheet material. U.S. Pat. No. 5,769,647 of Tulley et al. discloses such structure. This will no doubt increase the complexity of the connector. 
     In addition, there are different shapes and configurations among those eight terminals. Each terminal has its own shape which is different from each other, especially the 3rd and 6th terminals, each including the rectangular loop portion which overlaps to corresponding terminals to create desired electrical couplings. Each loop further forms the square to increase the electrical capacitances with corresponding terminals having the square. The electrical capacitances created can help to meet higher system requirements. The eight different configurations of the terminals will surely increase the difficulty and complexity in production. 
     There are some other approaches that include routing terminal tails of those 3rd, 6th and 4th, 5th terminals to alter their position and affect capacitances between 3rd, 2nd and 3rd, 4th; and 6th, 5th, and 6th, 7th terminals. However routing terminal tails will inevitably increase the manufacturing cost. 
     U.S. Pat. No. 6,120,329 of Steinman discloses another approach to solve the above-addressed problem. Again, terminals are configured with different shapes and dimensions making the production complex. 
     U.S. Pat. No. 5,069,641 of Sakamoto et al. discloses a suggestion of using substrate in the RJ modular housing; however, it addresses different issues. 
     SUMMARY OF THE INVENTION 
     A first object of this invention is to provide an RJ modular connector, and more particularly to an RJ modular connector having a printed circuit board (PCB) with conductive traces thereon to reduce crosstalk between contacts thereof. 
     A second object of this invention is to provide a method of manufacturing the above RJ modular connector. 
     A third object of the present invention is to provide a method of reducing crosstalk between contacts of an RJ modular connector. 
     To obtain the above objects, an RJ connector includes an insulative housing and a contact insert attached to the housing. The contact insert includes eight signal contacts and two grounding contact arranged side by side and an upper printed substrate and a lower printed substrate sandwiching the signal contacts and the grounding contacts therebetween. There is a grounded conductive material between at least two selected adjacent signal contacts for reducing capacitance between the two selected adjacent signal contacts. 
     As a second aspect of this invention, at least one selected signal contact is severed into pieces and two of the pieces are re-routed by conductive traces on a printed circuit board (PCB) but adjacent contacts are not severed. Therefore, length inducing electrical capacitance between the severed contact and the adjacent contacts can be reasonably reduced, thereby reducing crosstalk between the severed contact and the adjacent contacts. 
     As a third aspect of this invention, at least one selected signal contact is severed into three pieces and two end portions of the pieces are re-routed by conductive traces on a printed circuit board (PCB) and the middle portion is connected to a grounding trace. Therefore, the middle portion can provide grounding contact function to the severed and the adjacent signal contacts, thereby reducing crosstalk between the severed contact and the adjacent contacts. 
     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. 1 is a front perspective view of a modular jack connector of the present invention; 
     FIG. 2 is front planar view of FIG. 1; 
     FIG. 3 is a rear perspective view of the modular jack connector shown in FIG. 1; 
     FIG. 4 is a view similar to FIG. 3 except that a contact insert of the connector is disassembled from a housing; 
     FIG. 5 is an exploded perspective view of the contact insert shown in FIG. 4; 
     FIGS. 6 and 7 are planar view of opposite surfaces of an upper printed substrate; 
     FIGS. 8 and 9 are planar view of opposite surfaces of a lower printed substrate; 
     FIG. 10 is an enlarged bottom perspective view of the contact insert while the lower printed substrate is removed to clearly illustrate the attachment of the contacts onto the upper printed substrate; 
     FIG. 11 is a cross-sectional view of the contact insert taken along line XI—XI of FIG. 14; 
     FIG. 12 is a perspective view of a contact carrier stamped and formed during the manufacturing of the modular jack connector; 
     FIG. 13 is a view similar to FIG. 12 while the upper and the lower printed substrates sandwich the contact carrier; 
     FIG. 14 is a perspective view of the contact insert; and 
     FIG. 15 is a view similar to FIG. 14 but illustrating a second embodiment of the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS. 1,  2  and  3 , an electrical connector  1  in accordance with the present invention is illustrated from front and back perspectives. 
     Referring to FIG. 4, the connector  1  includes an insulative housing  10  and a contact insert  12  attached to the housing  10  from a back  14  of the housing  1 . The housing defines a chamber  18  through the back  14  and a front  16  of the housing  10  for engageably receiving the contact insert  12  therein. Above the chamber  18 , there are eight slots  20  isolated from each other except for bottom sections thereof communicating with the chamber  18  for receiving respective contacts (described later) of the contact insert  12 . Further above the chamber  18 , there are two channels  22  adjacent to respective two opposite side walls  24  of the housing  10  for engageably receiving two Light Emitting Diodes (LEDs) therein. 
     In the upcoming paragraphs, the configuration of the contact insert  12  will be illustrated in great detail, which illustrates the core of the present invention. 
     Referring to FIG. 5, the contact insert  12  generally includes eight signal contacts, designated by  26   a,    26   b,    26   c,    26   d,    26   e,    26   f,    26   g  and  26   h,  two grounding contacts, designated by  28   a  and  28   b,  and an upper printed substrate  30  and a lower substrate  32  sandwiching the eight signal contacts and the two grounding contacts therebetween. The signal contacts  26   a  and  26   b  are differential contacts that transmit simultaneous signals of opposite polarity. The signal contacts  26   d  and  26   e,    26   c  and  26   f,    26   g  and  26   h  are all differential contacts, and such arrangement is illustrated in the FIG.  3 ( a ) of the U.S. Pat. No. 5,941,734, issued to Matsushita Electric Works, Ltd. As shown in FIG. 5, a very important feature of the present invention is that the contacts  26   c  and  26   f  each are broken into three pieces, which will be illustrated in great detail later. 
     Referring to FIGS. 6 and 7, the upper printed substrate  30  has a first surface  34  and an opposite second surface  36 . On the first surface  34 , there are ten solder pads, generally designated by labels  38   a,    38   b,    38   c,    38   c ′,  38   d,    38   e,    38   f,    38   f ′,  38   g  and  38   h,  for electrically connecting the respective signal contacts  26   a,    26   b  . . .  26   h,  wherein the solder pads  38   c  and  38   c ′ connect the signal contact  26   c  and the solder pads  38   f  and  38   f ′ connect the signal contact  26   f.  The solder pads  38   a,    38   b,    38   c,    38   d,    38   e,    38   f,    38   g  and  38   f  are arranged side by side and are staggered along the two perpendicular directions of the first surface  34  except that the solder pad  38   c ′ generally locates at a same line with the solder pad  38   c,  and the solder pad  38   f ′ generally locates at a same line with the solder pad  38   f.  Between the solder pads  38   c  and  38   c ′ is a block of conductive plate  40   a  which has a width wider than the solder pad  38   c  and has two pieces  42   a,    42   b  extending to be located respectively at opposite sides of the solder pad  38   c.  Between the solder pads  38   f  and  38   f ′ is a block of conductive plate  40   b  which is a mirror of the conductive plate  40   a.  The conductive plate  40   b  has two pieces  44   a  and  44   b  positioned at two opposite sides of the solder pad  38   f.  There are two conductive bars  46   a  and  46   b  mounted on the first surface  34  and adjacent to opposite sides of the upper printed substrate  30 . 
     On the second surface  36 , there are three continuous loops, respectively designated by an inner loop  48   a,  a middle loop  48   b  and an outer loop  48   c.  Both the inner loop  48   a  and the outer loop  48   c  are insulative while the middle loop  48   b  is conductive. There are a first conductive panel  50   a  surrounded by the inner loop  48   a  and a second conductive panel  50   b  out of the outer loop  48   c  on the second surface  36 . 
     There are a plurality of dots which are actually conductive vias traveling through the upper printed substrate  30  for electrically connecting the conductive elements on the first surface  34  to the conductive elements on the second surface  36 . Two of the conductive vias, designated by  52   a  and  52   b,  are located on the middle loop  48   b  and respectively connect with the solder pads  38   f  and  38   f ′, thereby establishing a conductive route from the solder pads  38   f  through the via  52   a,  the middle loop  48   b  and the via  52   b  to the solder pad  38   f ′. It is clearly shown in FIG. 7 that the middle loop  48   b  has a first side section  49   a  and a second side section  49   b  respectively disposed to be in spatial registry with the solder pads  38   d,    38   h  for purpose described later. The other vias, designated by  54   a,    54   a ′,  54   b,    54   b ′,  54   c,    54   d,    54   e,    54   e ′,  54   f  and  54   f ′, electrically connecting the conductive bars  46   a,    46   b  and the conductive plates  40   a,    40   b  together through the conductive panels  50   a,    50   b,  thereby establishing a conductive route from the conductive panel  50   a  through the vias  54   b,    54   b ′, the conductive plates  40   b,  the via  54   c,  the conductive panel  50   b,  the vias  54   a,    54   a ′,  54   f  and  54   f ′, to the conductive bars  46   a,    46   b,  and a conductive route from the conductive plate  40   a  through the vias  54   e,    54   e ′ and  54   d,  the conductive panel  50   b  and the vias  54   a,    54   a ′,  54   f  and  54   f ′, to the conductive bars  46   a,    46   b.  The conductive panels  50   a,    50   b  may provide EMI shielding function when the conductive bars  46   a,    46   b  are grounded. 
     Referring to FIGS. 8 and 9, the lower printed substrate  32  has topologies on opposite surfaces thereof exactly the same as that of the upper printed substrate  30 . So, for concision, the lower printed substrate  32  is not described in great detail. 
     Now referring to FIG. 10 in conjunction with FIGS. 6 and 7, the two grounding contacts  28   a,    28   b  which are electrically connected to zero voltage via a grounding trace (not shown) are electrically attached to the conductive bars  46   a,    46   b.  The signal contacts  26   a,    26   b . . .    26   h  are respectively attached to the solder pads  38   a,    38   b . . .    38   h,  wherein the signal contact  26   c  is attached to the both solder pads  38   c,    38   c ′ and the signal contact  26   f  is attached to the both solder pads  38   f,    38   f ′. The signal contact  26   c  is severed into three pieces, designated by a mating portion  56   a,  a mounting portion  56   b  and a middle portion  56   c  between the mating portion  56   a  and the mounting portion  56   b.  The signal contact  26   f  is also severed into three pieces, designated by a mating portion  58   a,  a mounting portion  58   b  and a middle portion  58   c  between the mating portion  58   a  and the mounting portion  58   b.  The mating portion  58   a  is electrically connected to the mounting portion  58   b  through the route between the solder pads  38   f,    38   f ′ as clearly disclosed above. Therefore, signals transmitting through the signal contact  26   f  are rerouted to transmit through the first side section  49   a  and the second side section  49   b  of the middle route  48   b.    
     Since the first side section  49   a  of the middle route  48   b  is electrically connected to the signal contact  26   f  and is in spatial registry with the signal contact  26   d,  the capacitance between the signal contacts  26   f  and  26   d  is increased via the first side section  49   a  thereby being balanced with the capacitance between the signal contacts  26   f  and  26   e.  Same conditions happen between the signal contacts  26   f,    26   g  and  26   h.  When the lower printed substrate  32  mounts to the contacts, same conditions also happen between the signal contacts  26   c,    26   b  and  26   a,  and the signal contacts  26   c,    26   d  and  26   e.  Therefore, crosstalk between the signal contacts can be reduced. 
     As clearly shown in FIG. 10, since the middle portion  58   c  of the signal contact  26   f  is isolated from the mating portion  58   a  and the mounting portion  58   b  and no signal transmits therethrough, the signal contact  26   f  has a short length inducing capacitance with the adjacent signal contacts  26   e  and  26   g,  thereby reducing the capacitance between the signal contact  26   f  and the adjacent signal contacts  26   e  and  26   g.  This is helpful for balancing the capacitance between the signal contact  26   f  and the adjacent signal contacts  26   e  and  26   g  with the capacitance between the signal contact  26   f  and the far away signal contacts  26   d  and  26   h.  Same conditions also happen to the signal contacts  26   a,    26   b,    26   c,    26   d  and  26   e.  Therefore, crosstalk between the signal contacts can be further reduced. 
     Also as clearly shown in FIG. 10, between the signal contact  26   g  and the mating portion  58   a  of the signal contact  26   f  is the piece of conductive material  44   b.  Since the piece of conductive material  44   b  is connected to zero voltage, it provides a function grounding to reduce the crosstalk between the signal contacts  26   f  and  26   g.  Therefore, crosstalk between the signal contacts can be further reduced. 
     Also as clearly shown in FIG. 10, the middle section  58   c  of the signal contact  26   f  and the middle section  56   c  of the signal contact  26   c  are connected to zero voltage, thereby providing grounding function. This structure is also helpful for reducing crosstalk between the signal contacts. 
     FIG. 11 illustrates the conductive pads and the vias described above and the contacts arrangement. It is clearly shown that all the signal contacts  26   a,    26   b . . .    26   h  and the grounding contacts  28   a,    28   b  are disposed in a same layer or plane, thereby reducing the thickness of the contact insert  12 . 
     Referring to FIGS. 12-14, during the manufacture of the connector  1 , a metal sheet is stamped and formed to form a contact carrier  60  having eight signal pins  62   a,    62   b . . .    62   h  arranged side by side and two grounding pins  64   a,    64   b  disposed at outmost sides thereof, and two pieces of carrier strips  66   a,    66   b  connecting opposite ends of the signal pins and the grounding pins. The upper and lower printed substrates  30 ,  32  are securely attached to and sandwich the contact carrier  60  therebetween with the signal pins  62   a,    62   b . . .    62   h  and the grounding pins  64   a,    64   b  electrically connecting corresponding solder pads  38   a,    38   b . . .    38   h  on the upper and the lower printed substrates  30 ,  32 . Then a semi-insert  68  is formed, which is shown in FIG.  13 . The signal pins  62   c  and  62   f  each are then severed into three pieces. The carrier strips  66   a,    66   b  are severed from the contact carrier  60  and the signal pins  62   a,    62   b . . .    62   h  are reformed to form the contact insert  12 . After that, assembling the contact insert  12  to the housing  10 . 
     Referring to FIG. 15, a second embodiment of the present invention is illustrated. The connector is similar to that of the first embodiment except that a contact insert  70  has a small difference from the contact insert  12  of the first embodiment. The contact insert  70  has an upper printed substrate  72 , a lower printed substrate  74  and eight signal terminals, designated by  76   a,    76   b . . .    76   h,  arranged side by side and sandwiched between the upper and the lower printed substrates  72 ,  74 . The signal terminals  76   c,    76   f  each are severed to three pieces and the middle pieces are removed away from the contact insert  70  and leave two elongate slits  78   a,    78   b.    
     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.