Patent Publication Number: US-6663428-B1

Title: Electrical connector with improved grounding terminal arrangement

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This patent application is related to U.S. Pat. No. 6,589,066 filed Jul. 30, 2002, titled “ELECTRICAL CONNECTOR HAVING LATCHING MECHANISM”, both of which assigned to the common assignee and which are hereby fully incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an electrical connector, and in particular to an electrical connector which provides suitable impedance for balanced transmission. 
     2. Description of Related Art 
     With the development of communication and computer technology, high density electrical connectors with conductive elements in a matrix arrangement are desired to construct a large number of signal transmitting paths between two electronic devices. Such high density electrical connectors are widely used in internal connecting systems of severs, routers and the like devices requiring high speed data processing and communication. 
     U.S. Pat. No. 6,183,302 issued to Osamu Daikuhara et al. and on Feb. 6, 2001 discloses a high density connector which includes a dielectric housing, a plurality of signal and grounding contacts alternately disposed in the dielectric housing, wherein the first and second signal contacts can provide about 50 Ω impedance. However, in this way, the impedance of each signal contact cannot be accurately controlled in a suitable range. Specially, in differential pair technique, the steady impedance is the key to balanced transmission. By the way, the differential pair of technique means that a signal is transmitted via two paths, wherein each path has the same length as the other path. Furthermore, even we can improve impedance function of the signal contacts via modifying shape or size of the signal contacts, but these methods are wasteful, which cannot be easily used in any condition, specially for some connectors having definite standard. 
     It is thus desirable to provide an electrical connector which can resolve above problem in prior art. 
     SUMMARY OF THE INVENTION 
     Accordingly, an object of the present invention is to provide an electrical connector which can satisfy the impedance needs of application. 
     In order to achieve the object set forth, an electrical connector in accordance with the present invention comprises an upper housing, a bottom housing and a terminal module. The upper housing and the bottom housing together define a space and a mating port positioned near the space. The terminal module has a base, a tongue extending in the mating port from the base, and a plurality of signal and grounding terminals therein. The signal terminals are disposed opposite sides of the tongue in pairs. A square hole is formed in the tongue and parallel to the signal terminals. 
     Furt hermore, the tongue defines a plurality of through grooves and grooves arranged alternately to each other. The terminal module may comprise a circuit board for engaging with the first grounding terminals and signal terminals. The grounding terminals consist of first grounding terminals for engaging with a mating connector and second grounding terminals for shielding the signal terminal. 
    
    
     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 
     FIG. 1 is a perspective view of an electrical connector in accordance with the present invention; 
     FIG. 2 is an exploded view of the electrical connector shown in FIG. 1; 
     FIG. 3 is a perspective view of a terminal module of the connector with a circuit board removed from the terminal module to facilitate the illustration; 
     FIG. 4 is a cross-sectional view of FIG. 3 taken along line  4 — 4  of FIG. 3; 
     FIG. 5 is a cross-sectional view of FIG. 3 taken along line  5 — 5 ; 
     FIG. 6 is a cross-sectional view similar to FIG. 5 but taken along line  6 — 6  of FIG. 3; 
     FIG. 7 is an exploded view of the terminal module shown in FIG. 3; and 
     FIG. 8 is a perspective view of the terminal module with grounding terminals about to be inserted into the module. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIGS. 1 and 2, an electrical connector  1  in accordance with the present invention comprises an upper housing  2 , a bottom housing  3 , and a terminal module  4  located between the upper and bottom housings  2  and  3 . The upper housing  2  defines a mating port  20  and a push bar  22  at opposite ends thereof. The bottom housing  3  defines an ejector mechanism  30  for retention of a complement connector (not shown), and an opening  32  for extension of a cable at rear portion thereof. 
     Referring to FIGS. 3 and 4, the terminal module  4  comprises a base  400 , a tongue  41  projecting forward from the base  400  for mating, a pair of leading arms  42  extending from both sides of the base  400  and an inner circuit board  43  (FIG. 2) disposed between the pair of leading arms  42  and adjacent to rear portion of the base  40 . The base  400  forms a plurality of protrusions  400  beyond two sidewalls  403  and an upper surface  405  thereof, and a pair of ribs  401  extending rearward from the base  400 . The ribs  401  further define a rear surface  402  facing the circuit board  43 . The tongue  41  defines a front surface  410  parallel to the rear surface  402  and facing to the complement connector. A plurality of through grooves  414  are defines in the tongue  41 , and a plurality of grooves  416  are formed between every two adjacent through grooves  414  and positioned at both side of the tongue  41  in pairs. In addition, the tongue  41  has a plurality of square holes  418  between every pair grooves  416 , wherein the square holes  418  not extend into the base  40 . In this preferable embodiment, each square hole  418  is aligned with a pair of grooves  416 , but the hole  418  needn&#39;t always be aligned with the pair of grooves  416 . Generally, the terminal module is mold in plastics, which has better insulative than the air. Thus, whole impedance of the connector  1  molded mainly by plastics cannot meet with serious signal transmission in high speed and high density condition. While via the square holes  418 , there are filled with air, which has better electrical conductivity to ensure balanced impedance. In other words, due to providing square holes  418  in the terminal module  4 , the whole impedance of the connector  1  is controlled in a rational range. 
     Referring to FIGS. 5-7, each rib  401  forms a plurality of recesses  404 . A plurality of passageways  406  is formed through the base  40  and communicates with corresponding through grooves  414 . A plurality of passages  408  are formed through the base  40  and each communicates with a corresponding groove  416 . Specially, each recess  404  is aligned with a corresponding passageway  406  in a vertical direction. Each passageway  406  has a smaller width at middle portion and has bigger width at both ends thereof. Furthermore, the tongue  41  defines a plurality of holes  412  to provide each through groove  414  an opening to the front surface  410 . The through grooves  414  and the passageways  406  together define a terminal-receiving space for receiving grounding terminals, and the grooves  416  and passages  408  together define a contact-receiving space for receiving signal terminals. 
     A plurality of terminals are received in the terminal module  4  and divided into first grounding terminals  5 , second grounding terminals  6 , first signal terminals  7  and second signal terminals  8 . Referring to FIG. 7 please, each first grounding terminal  5  includes a limb  50  and a pair of wings  52  extending from an end of the limb  50 . At opposite ends of the limb  50 , there defines a tip  500  to cooperate with the hole  412  and a needle hole  502  to create flexible contact force, respectively. Each wing  52  defines an engaging portion  520 . Each second grounding terminal  6  includes a retention portion  60  for retaining the terminal  6  in the terminal module  4 , and a contact portion  62  for engaging the circuit board  43 . Each first signal terminal  7  includes a retention portion  70 , and a contact portion  72  and a curved portion  74  extending in opposite directions and from the retention portion  70 . The curved portion  74  further defines an engaging portion  740  for connecting the circuit board  43 . Each second signal terminal  8  includes a retention portion  80 , and a contact portion  82  and a curved portion  84  extending in opposite directions and from the retention portion  80 . The curved portion  84  further defines an engaging portion  840  for connecting the circuit board  43 . In addition, the length of the second grounding terminals  6  is equal to the length of the retention portion plus the contact portion of each first and second signal terminal  7  and  8 . Furthermore, in assembly, the contact portion of the second grounding terminals  6  and the first and second signal terminals  7 ,  8  has flat shape and is parallel to the upper surface  405  of the base  40 , while the limb  50  of the first grounding terminals  5  has also flat shape but being arranged perpendicular to the upper surface  405  of the base  40 . 
     Referring back to FIGS. 5 and 6 in conjunction with FIG. 8, in assembly, the second grounding terminals  6  are firstly inserted into the passageways  406  of the base  40  and further entirely in the through grooves  414  of the tongue  41  in pairs. The first and second signal terminals  7  and  8  are inserted into passages  408  of the base  40  and further in the grooves  416  of the tongue  41 . The flat contact portions  62 ,  72  and  82  are arranged in both side of the tongue  41  thereby providing enough surfaces for mating with the complement connector. Subsequently, the first grounding terminals  5  are inserted into the passageways  406  of the base  40  in the direction of arrow “A” which represents the “insertion direction” of the terminals, and further into the through grooves  414  until the tip  500  extends into corresponding hole  412  of the tongue  41 , wherein the limb  50  engages every adjacent pair of first grounding terminals  5  and the wings  52  are retained in the recesses  404  to prevent unnecessary deformation. Specially, the needle hole  502  provides flexible contact force between the first and second grounding terminals  5 ,  6 . Then the wings  52  of the second grounding terminals  5 , and the curved portions  74  and  84  of the first and second signal terminals  7  and  8  are disposed in the receiving cavity  403  of the base  40  and beyond the rear surface  402 . Thus, the circuit board  43  (FIG. 2) can be retained between the pair of leading arms  42 , and between the wings  52  and the curved portions  74  and  84  via interfering with the engaging portions  520 ,  740  and  840 . In addition, along with insertion direction and perpendicular to the upper surface  405 , the wings  50  each has bigger surface relative to the curved portions  74  and  84  thereby providing better grounding protection for signal transmission. 
     Referring back to FIGS. 1 and 2, the terminal module  4  is entirely received in a space defined by the upper and bottom housings  2  and  3 , wherein the tongue  41  extends in the mating port  20 . The ejector mechanism  30  provides a way to exit the complement connector. A cable (not shown) can extend through the opening  32  and further contact with the circuit board  3  of the terminal module  4 . 
     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.