Patent Publication Number: US-8523611-B2

Title: Electrical connector having contact modules with differential pairs on both sides of a printed circuit board

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an electrical connector of high density with lower profile. 
     2. Description of Related Art 
     U.S. Pat. No. 6,899,566, issued to Kline et al. on May 31, 2005, discloses a backplane connector mounted on one side of a daughter card. However, there is no disclosure about how to arrange the connector on both sides of the daughter card to achieve a low profile. 
     U.S. Pat. No. 4,871,321, issued to Johnson et al. on Oct. 3, 1989, discloses a backplane connector in which contact pins extending from separate portions thereof are adapted to enter a circuit board from both sides. The connector has two connector portions mounted on opposite sides of a daughter card. However, a pair of pins are used to latch the two connector portions which increases the profile of the connector. 
     U.S. Pat. No. 6,663,415, issued to Wu on Dec. 16, 2003, discloses a high speed cable assembly in which two rows of contacts define a slot receiving a printed circuit board. However, the contact density is very limited. 
     Additionally, the contacts disclosed in latter two prior art references are prone to damage since the contacts are exposed to outside during most of the manufacturing processes of the connector. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a cable assembly comprising a cable and an electrical connector connected to an end of the cable. The electrical connector further comprises a printed circuit board having a rear edge connected to the cable and a front edge opposite to the rear edge, a plurality of upper contact modules stacked along the front edge on a top side of the printed circuit board, and a plurality of lower contact modules stacked along the front edge on a bottom side of the printed circuit board. Each of the upper contact modules has at least one first conductor pairs for transferring signal differential pairs lined along a column perpendicular to the printed circuit board and a first insulator encapsulating a center portion of each first conductor of the first conductor pairs. Each first conductor of the first conductor pairs further comprises a front portion for mating with a complementary connector and a rear portion mounted onto the printed circuit board. Each of the lower contact modules has a plurality second conductor pairs for transferring signal differential pairs lined along a column perpendicular to the printed circuit board and a second insulator encapsulating a center portion of each second conductor of the second conductor pairs. Each second conductor of the second conductor pairs further comprises a front portion for mating with the same complementary connector and a rear portion mounted onto the printed circuit board. 
     Another object of the present invention is to provide an electrical connector comprising a printed circuit board, a plurality of stacked upper contact modules mounted on a top side of the printed circuit board, and a plurality of stacked upper contact modules mounted on a bottom side of the printed circuit board. The printed circuit board has a front edge defining a plurality of first plated through holes disposed in a rear area and a plurality of second plated through holes disposed in a front area. Each of the upper contact modules has at least one first conductor pairs for transferring signal differential pairs lined along a column perpendicular to the printed circuit board and a first insulator encapsulating a center portion of each first conductor of the first conductor pairs. Each first conductor of the first conductor pairs further comprises a front portion for mating with a complementary connector and a rear portion mounted into corresponding first plated through hole of the printed circuit board. Each of the lower contact modules has at least one second conductor pairs for transferring signal differential pairs lined along a column perpendicular to the printed circuit board and a second insulator encapsulating a center portion of each second conductor of the second conductor pairs. Each second conductor of the second conductor pairs further comprises a front portion for mating with the same complementary connector and a rear portion mounted into corresponding second plated through hole of the printed circuit board. 
     Since the contact modules are disposed on opposite sides of the printed circuit board, the height of the electrical connector could be lowered and the space on opposite side of the printed circuit board is fully used to receive the conductor pairs and the cable end soldered onto the printed circuit board. Furthermore, the qualified impedance of the conductor pairs is easier to obtained since the rear portions of the conductor pair are disposed one adjacent to the other. 
     Other objects, advantages and novel features of the invention will become more apparent from the following detailed description of a preferred embodiment when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a cable assembly according to an embodiment of the present invention; 
         FIG. 2  is a perspective view of the cable assembly shown in  FIG. 1  except that a top conductive cover is removed away; 
         FIG. 3  is a bottom perspective view of the top conductive cover shown in  FIG. 2 ; 
         FIG. 4  is a perspective view of the cable assembly shown in  FIG. 1  except that a cable, a protecting insulator and conductive covers are removed; 
         FIG. 5  is an exploded view of the subassembly shown in  FIG. 4 ; 
         FIG. 6  is an exploded view of an upper contact module and an adjacent conductive plate with shown in  FIG. 5 ; 
         FIG. 7  is an exploded view of a lower contact module and an adjacent conductive plate with shown in  FIG. 5 ; and 
         FIG. 8  is a diagram showing the engagement of the conductor and the printed circuit board. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference will now be made to the drawing figures to describe the present invention in detail. 
     Referring to  FIG. 1 , a cable assembly  100  comprises a cable  10  and an electrical connector connected to an end of the cable  10 . 
     Referring to  FIGS. 2-5 , the electrical connector further comprises a printed circuit board  12  having a rear edge connected to the cable  10  and a front edge opposite to the rear edge, a plurality of upper contact modules  21  stacked along the front edge on a top side  122  of the printed circuit board  12 , and a plurality of lower contact modules  22  stacked along the front edge on a bottom side  124  of the printed circuit board  12 . The cable  10  has a plurality of conductors (not shown) soldered onto opposite sides of the printed circuit board  12 , and then the soldered portions are over-molded with a protecting insulator  102 . Each of the upper contact modules  21  has a first conductor pairs  141 ,  142  for transferring signal differential pairs lined along a column perpendicular to the printed circuit board  12  and a first insulator  152  encapsulating a center portion of each first conductor of the first conductor pairs  141 ,  142 . Each first conductor  141 ,  142  further comprises a front portion for mating with a complementary connector (not shown) and a rear portion  146  mounted onto the printed circuit board  12 . Each of the lower contact modules  22  has a second conductor pairs  143 ,  144  for transferring signal differential pairs lined along a column perpendicular to the printed circuit board  12  and a second insulator  156  encapsulating a center portion of each second conductor  143 ,  144  of the second conductor pairs. Each second conductor  143 ,  144  further comprising a front portion for mating with the complementary connector and a rear portion  146  mounted onto the printed circuit board  12 . 
     Referring to  FIGS. 5-7 , the electrical connector further comprises a first front housing  31  and a second front housing  32 . The first front housing  31  receives the front portions of the first conductors  141 ,  142  of each upper contact modules and engages with the first insulators  152 . The second front housing  32  receives the front portions of the second conductors  143 ,  144  of each lower contact modules  22  and engages with the second insulators  156 . The electrical connector further comprises a plurality of conductive plates  25 ,  26  adjacent each upper contact module  21  and lower contact module  22 . Each of the conductive plates  25 ,  26  has a plurality of front portions (not labeled) for mating with the complementary connector. The insulator  152 ,  156  of each contact module  21 ,  22  defines a recess (not labeled) to receiving the adjacent conductive plate  25 ,  26  and the conductive plate  25 ,  26  is fixed to said contact module  21 ,  22 . 
     Referring to  FIGS. 4 ,  5  and  8 , the printed circuit board  12  defines a plurality of first plated through holes  123  disposed in a rear area receiving the rear portions  146  of the first conductors  141 ,  142  and a plurality of second plated through holes  123  disposed in a front area receiving the rear portions  146  of the second conductors  143 ,  144 . The first plated through holes  123  corresponding to an upper contact module  21  and the second plated through holes  123  corresponding to a lower contact module  22  are disposed in a line. The printed circuit board  12  defines a pair of holes  126  filled by plastic material of the protecting insulator  102  so that the printed circuit board  12  is firmly secured by the protecting insulator  102 . 
     The electrical connector further comprises a top conductive cover  104  and a bottom conductive cover  106  closed together. The top conductive cover  104  and the bottom conductive cover  106  define a cavity there between and the protecting insulator  102 , the printed circuit board  12  and the plurality of upper and lower contact modules  21 ,  22  are received therein. The top conductive cover  104  forms a protrusion  105  including a rib  109  and two tabs  107 . The rib  109  forwardly abuts the first insulator  152  of each upper contact modules  21 . The stacked upper contact modules  21  are positioned between the two tabs  107 . The bottom conductive cover  106  forms a rib and two tabs (not shown) similar to the top conductive cover  104 . The top conductive cover  104  and the lower conductive  106  forms a plurality of block  108  (shown in  FIG. 3 ) for abutting the protecting insulator  102  thereby firmly securing the protecting insulator  102  therein. 
     The disclosure is illustrative only, changes may be made in detail, especially in matter of shape, size, and arrangement of parts within the principles of the invention.