Electrical connector having improved shielding means

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BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an electrical connector used to interconnect printed circuit boards, and particularly to such an electrical connector which is provided with an improved shield means.

2. Description of Prior Art

Backplane connectors are commonly used in backplane systems to electrically interconnect a daughter board or an inserted card to a backplane or a mother board which are substantially located at a right angle with respect to each other for transmitting high speed signals or data between the two boards. A backplane connector generally comprises a receptacle connector, usually named as a pin header, mounted on a backplane, and a plug connector mounted on a daughter board for mating with the receptacle connector. Such backplane connectors are disclosed in U.S. Pat. Nos. 5,993,259, 5,860,816 and 5,980,321. A receptacle connector comprises a plurality of wafers stacked side-by-side and each wafer includes a dielectric body, a number of signal terminals integrally formed in the dielectric body and a conductive shield covering on the dielectric body for providing Electro Magnetic Interference (EMI) shielding for the signal terminals of adjacent wafers. With the development trend in computers, backplane connectors are becoming more and more miniature while transmitting signals or logics with higher and higher speed in backplane systems, therefore, signal terminals of the backplane connector are becoming higher and higher in density. Therefore, to effectively overcome EMI or cross talk between adjacent signal terminals of the backplane connector is an important issue. However, the above-mentioned U.S. patents only disclose EMI shielding for the signal terminals between adjacent wafers by the conductive shield, but do not disclose EMI shielding between adjacent signal terminals within each wafer. Hence, a backplane connector with improved EMI shielding is desired.

BRIEF SUMMARY OF THE INVENTION

A first object of the present invention is to provide an electrical connector which is provided with an excellent shielding function;

A second object of the present invention is to provide an electrical connector having a shielding mechanism which is easy manufactured and low in cost.

To fulfill the above-mentioned objects, an electrical connector in accordance with the present invention used in backplane systems comprises a plurality of wafers side-by-side staked with each other. Each Wafer includes a signal piece and a shield piece covered onto the signal piece. The signal piece is formed with a dielectric body and a plurality of signal terminals insert molded with the dielectric body. The dielectric body defines a plurality of through slots and a corresponding number of undercuts corresponding to the through slots both extending from one side to the other side thereof. The shield piece comprises a metal plate which is integrally formed with a plurality of first ribs and a corresponding number of second ribs corresponding to the first ribs formed through die-case for tightly insertion into corresponding through slots and undercuts of the signal piece, respectively. In addition, lower tip ends of the first ribs and top tip ends of the second ribs are overlapped or at least located on a common plane to effective block EMI among the signal terminals within each wafer.

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 an exploded view of a unit of an electrical connector in accordance with the first embodiment of the present invention;

FIG. 2 is a perspective view of a shield piece of FIG. 1;

FIG. 3 is an exploded perspective view of an electrical connector in accordance with the first embodiment of the present invention;

FIG. 4 is an assembled view of FIG. 3;

FIG. 5 is a front view of FIG. 4;

FIG. 6 is a cross-sectional view taken on line 6--6 of FIG. 4;

FIG. 7 is a cross-sectional view taken on line 7--7 of FIG. 4; and

FIG. 8 is a front view of an electrical connector in accordance with a second embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made to drawings, and first to FIGS. 3 and 4, an electrical connector 1 in accordance with the first embodiment of the present invention, generally named as plug connector, is used to be mounted on a daughter board (not shown). The connector 1 is adapted for mating with a header connector (not shown) mounted on a backplane or mother board located substantially at an right angle with respect to the daughter board, thereby electrically interconnecting the daughter and mother boards. The electrical connector 1 comprises multiple wafers 10 which have an identical structure with each other and are stacked together side by side. Thus, only one wafer 10 will be described below.

Referring to FIGS. 1 and 2, the wafer 10 includes a signal piece 11 and a shield piece 21 attached to the signal piece 11 for providing EMI shielding function. The signal piece 11 comprises a dielectric body 12 and a plurality of signal terminals 14 insert molded in the dielectric body 12. In the prefer embodiment of the present invention, there are total eight signal terminals 14 insert molded in each dielectric body 12 and each terminal 14 includes a retaining portion embedded in the dielectric body 12, a press-fit tail 142 and a fork-like mating portion 144 extending from opposite ends of the retaining portion, respectively. The detail of the signal terminal 14 is described in the application cross-referenced. The press-fit tail 142 extends beyond a side face 122 of the body 12 for insertion into a corresponding hole (not shown) defined in the daughter board, and the fork-like mating portion extends from a bottom face 124 of the body 12 for engaging with a corresponding terminal pin (not shown) of the header connector mounted on the mother board. The dielectric body 12 defines several through slots 15 extending through opposite side surfaces 127 thereof for dividing the body 12 into a corresponding number of sections. In the prefer embodiment of the present invention, there are three through slots 15 dividing the body 12 into four sections 121, each section 121 including two terminals 14 therein. The body 15 further defines three undercuts 16 corresponding to the three slots 15 at a bottom side 124 thereof and leaves a slim bridge 123 interconnecting each undercut 16 to a corresponding slot 15. Further referring to FIG. 5, bottom tips 152 of the slots 15 and top tips 162 of the undercuts 16 are substantially located on a common plane, designated as a dotted line 20, which is substantially vertical to the electrical connector 1.

Referring to FIGS. 1 and 2 again, the shield piece 21 is stamped and formed from a metal sheet and is constructed in a structure corresponding to the signal piece 1. The shield piece 21 is formed with a metal plate 22 with a plurality of slits 221 and openings 223 corresponding to the contours of the slots 15 and undercuts 16, respectively, as shown in FIGS. 6 and 7. Then, each slit 221 or an opening 223 is further formed with a first rib 23 or second rib 25 through the die-cast molding. Further referring to FIGS. 5 to 7, the first ribs 23 and second ribs 25 have substantially the same structures as the slots 15 and the shorter slots 16, respectively, and both are symmetric about the metal plate 22 and have an identical width substantially equal to that of the slot 15 or the undercut 16. Thus, each first rib 23 or second rib 25 is inserted into substantially a half depth of a corresponding through slot 15 or undercut 16 of the signal piece 11. A passageway 222 is left between a lower tip 234 of each first rib 23 and an upper tip 254 of a corresponding second rib 25. The lower tips 234 of the first ribs 23 are located on a first common plane 20 and upper tips 254 of the second ribs 25 are located on a second common plane 20', wherein the first and second common planes 20, 20' are overlapped. A plurality of grounding tails 24, shaped in press-fit type, extend from a lateral side of the metal plate 22 for press-fitting into a corresponding grounding hole (not shown) defined in the daughter board. Several pairs of grounding legs 26 are formed on a bottom side 27 of the metal plate 22 for mating with corresponding grounding pins (not shown) of the mating header connector and are seperated from each other by a corresponding number of tabs 29. The metal plate 22 is further formed with a plurality of peripheral wedges(flanges) 30 substantially extending at an right angle with respect to the metal plate 22, thereby jointly defining a receiving space 31 for snugly covering on the signal piece 11.

In assembly, referring to FIGS. 3 to 7, each signal piece 11 and a corresponding shield piece 21 are first side-by-side assembled with each other with halves of the first ribs 23 or the second ribs 25 on one side opposite to the peripheral wedges 30 thereof being inserted into substantially half depth of a corresponding slot 15 or undercut 16 of the signal piece 11, resulting in each wafer 10. Then, the plural wafers 10 are side-by-side stacked together with halves of the first ribs 23 and second ribs 25 on the other side of each wafer 10 inserted into the other half depths of the corresponding slots 15 and shorter slots 16 of an adjacent wafer 10, respectively. Additionally, the peripheral wedges 30 of one wafer 10 is snugly covered on a corresponding signal piece 11 of the adjacent wafer 10, thereby forming the whole electrical connector 1, as shown in FIG. 4.

Using this arrangement, the electrical connector 1 in accordance with the present invention is provide with an excellent EMI shielding function for each wafer 10 thereof. As shown in FIG. 4, the signal pieces 11 are securely shielded from each other by the metal plates 22 of the shield pieces 21 arranged among them. Especially, further referring to FIGS. 6 and 7, within each signal piece 11, every two signal terminals 14 within each section 121 thereof are totally shielded from each other by the first ribs 23 and second ribs 25 of the two associated shield pieces 21 being totally blocked within a corresponding slot 15 and a undercut 16, respectively. Furthermore, as shown in FIG. 5, since the first ribs 23 and the corresponding second ribs 25 are located in the common plane 20, they totally shield cross-talk or EMI for the signal terminals 14 of each section 121 from each other.

Referring to FIG. 8, an electrical connector 1' in accordance with a second embodiment of the present invention is shown. The electrical connector 1' has substantially the same structure as that of the electrical connector 1 except for slots 15' and undercuts 16' of the signal piece 11', and first and second ribs 23', 25' of the shield piece 21', thus only the different structures therebetween are illustrated hereinafter. Each slot (first rib) 15'(23') and a corresponding undercut (second rib) 16'(25') respectively have a lower tip end 152'(234') and an upper tip end 162 (254') which are overlapped to provide a more effective EMI or cross-talk shielding for the signal terminals 14' within each section 121' of the signal piece 11'.

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.

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