Electrical connectors

Abstract: An electrical connector (10) is disclosed which includes a dielectric housing (16) with passages for receiving a plurality of signal terminals (26). A common ground member (20) is disposed in the dielectric housing with portions (34) thereof disposed between the individual signal terminals. The ground member has a passage (30) for receiving a ground terminal (32).

Description: Field of the Invention This invention generally relates to the art of electrical connectors and, particularly, to a hybrid electrical connector for accommodating both high frequency transmission as well as lower frequency transmissions. Background of the Invention Electrical connectors are used to interconnect signal transmission lines to printed circuit boards, other electronic devices or to other complementary connectors. The transmission lines transmit signals through a plurality of conductors which, preferably, are physically separated and electromagnetically isolated along their length. In the electronics industry, particularly the computer industry, the predominant system embodies a plurality of plug-in type connectors in mating engagement with receptacle connectors on the computer, its main printed circuit board or other electronic devices. The transmission lines typically include coaxial electrical cables, either in round or flat form, and round cables are presently being used predominantly in relatively high frequency applications between various system components. Classical coaxial designs derive their characteristic impedance from the geometrical relationship between the inner signal conductors and the outer shield member and the intervening dielectric constant. For a given impedance, signal conductor size and dielectric material, an overall outside dimension is defined. In order to increase signal density and reduce the overall outside dimensions of a transmission line connector system, alternate geometries and/or dielectric materials are required. For data processing purposes, cables usually utilize twisted pairs of conductors to achieve the necessary characteristics, particularly impedance control and cross talk control. Coaxial cables are used in singular conductor configurations in high frequency applications, such as to a high-speed video monitor. Most often, the lower speed data transmission lines are separated from the high speed signal transmission lines. Consequently, different electrical connectors are often used for the lower speed data transmission lines than for the high speed signal lines. This adds to the problem of requiring multiple connectors in ever-increasing miniaturized and high density application. An electrical connector according to the preamble of claim 1 is already known from US-A-4,846,711 wherein the second terminals are formed by three coaxial connectors arranged side by side, each having an axial cylindrical shell and a conductor center contact. Such an arrangement however consumes a considerable amount of space and requires separate terminations. This invention is directed to solving such problems by providing an electrical connector which terminates both high speed signal transmission lines and the slower data transmission lines in a unique manner providing a common ground for the signal transmission lines. Summary of the Invention An object, therefore, of the invention is to provide a new and improved system, as well as an electrical connector, for interconnecting signal transmission lines in electronic devices, such as computers or the like. The invention is defined in claim 1. According to an aspect of the invention, an electrical connector is provided as an interface between a plurality of high speed transmission lines and an electronic device, particularly a printed circuit board of the device. The connector includes a common ground system for all of the high frequency conductors to reduce the number of interconnections predominant in the prior art and to increase signal density while maintaining a desired impedance level. As disclosed herein, the interconnection with the high frequency conductors is combined with terminals for interconnection to a plurality of slower data transmission lines to create a matrix-type hybrid connector. Other objects, features and advantages of the invention will be apparent from the following detailed description taken in connection with the accompanying drawings. Brief Description of the Drawings The features of this invention which are believed to be novel are set forth with particularity in the appended claims. The invention, together with its objects and the advantages thereof, may be best understood by reference to the following description taken in conjunction with the accompanying drawings, in which like reference numerals identify like elements in the figures and in which: FIGURE 1 is a front elevational view of a connector embodying the present invention; FIGURE 2 is a perspective view of the insulators used in the connector of Figure 1; FIGURE 3 is a vertical section through one of the insulators shown in Figure 2, namely the bottom right-hand insulator of Figure 2; FIGURE 4 is a perspective view similar to that of Figure 3, with a contact loaded into the insulator; FIGURE 5 is a vertical section taken generally along line 5-5 of Figure 1; FIGURE 6 is a fragmented elevational view of an alternate embodiment of the invention in comparison to that shown in Figure 1; FIGURE 7 is a perspective view of the housing utilized in Figure 6; FIGURE 8 is a perspective view of a tail aligner that could be utilized with the housing of Figure 7 or the connector of Figure 1; FIGURE 9 is a perspective view of a ground member utilized in Figure 6; FIGURE 10 is a perspective view showing another alternative embodiment of the invention as compared to Figure 6; and FIGURE 11 is an elevational view of a further embodiment of the invention in comparison to the embodiments illustrated in Figures 1 and 6. Detailed Description of the Preferred Embodiment Referring to the drawings in greater detail and first to Figure 1, the invention contemplates a hybrid electrical connector that terminates both the conductors for data transmission lines and the conductors of high frequency transmission lines. More particularly, electrical connector 10, includes receptacle portion 12 having contact portions 14 of a plurality of terminals mounted therein exposed for engagement with appropriate contacts of a complementary mating male or plug-in connector. The left-hand portion or section of electrical connector 10 shown in Figure 1 forms a standard data connector. However, the right-hand portion or section of connector 10 provides a high frequency connector. Still referring to Figure 1, connector 10 includes a dielectric housing 16 surrounded by a conductive shield 18 which spans substantially the entire length of the connector. An alternate embodiment of the housing is shown in Figure 7. A single or common ground member 20 of die-cast metal material, or the like, surrounds four quadrants which are filled by separate insulator members 22. Each insulator member 22 has a passage 24 for receiving signal contacts or terminals 26. Such passage 24 can be positioned within insulator 22 and with respect to ground member 20 in order to provide controlled impedance. Ground member 20 has a central circular portion 28 surrounding a passage 30 for receiving a ground contact or terminal 32. Ground member 20 is shaped to have spokes or webs 34 dividing the interior of the ground member into the quadrants. Therefore, it can be seen in Figure 1 that all of signal contacts 26 and ground contact 32 are surrounded by the single ground member 20. This is in striking contrast to prior systems wherein typical coaxial interface designs use separate or discrete ground connections which consume a considerable amount of space and require separate terminations. With the single ground member 20 surrounding all of the contacts, a common ground plane is provided to control impedance, emissions of radiation and cross talk between the contacts. Figure 2 shows all four insulators 22 in a perspective depiction as they are located within ground member 20. Figure 3 shows a section through one of the insulators 22 to illustrate the configuration of passage 24 therethrough. It can be seen that the passage has an entry end 40 for receiving a contact of a complementary connector, a back wall 42, a through passage portion 44 and a shoulder 46. With the above-described configuration of the interior passages of each insulator 22 in relation to Figure 3, reference is made to Figures 4 and 5 wherein a signal contact, generally designated 26, is shown positioned in passages 24. Each contact 26 includes a contact end 50 and a solder tail end 52. The contact end is disposed in passage 24 and the solder tail is provided for interconnection to a circuit trace on a printed circuit board as is known in the art. Contact end 50 is fabricated by a plurality of contact spring arms which are "crowned" for high hertzian interfacing with a receptacle-contact of the complementary connector. Each contact 26 is securely locked into position within its respective insulator 22 by means of a base portion 54 of the contact engaging back wall 42 of the insulator, and the base portion is provided with a locking barb 56 for snapping behind shoulder 46 of its insulator. In assembly of contacts 26 into insulators 22, solder tail portion 52 initially extends parallel to the axis of the contact end 50 so that the contacts can be loaded into insulators 22 in the direction of arrows "A" in Figure 5. When base portions 54 of the contacts engage back walls 42 of the insulators, locking barbs 56 snap behind shoulders 44 of the insulators. Solder tails 52 then are bent downwardly as shown in Figures 4 and 5. Figure 5 also shows the positioning of shield 18 and how it surrounds housing 16 and common ground member 20. Shield 18 includes locking projections 59 which extend through openings in the dielectric housing 16, in the ground member 20 and in the back cover shielding member 64 to be engaged in openings similar to those (60) in Figure 7 in the dielectric housing 16′. The back cover shielding member 64 is made from a conductive material. These components are dimensioned so that the shield 18, ground member 20 and back cover 64 are mechanically and electrically secured to complete the ground circuit between them. Back cover 64 covers and shields the rear portion of the connector and the tail portions of the terminals. Solder tail portions 52 are shown extending through passages in tail aligner 66. The solder tail portions 52 of the terminals 26, 32 have three different lengths. The longest solder tails are connected to the upper terminals 26 and extend through holes 68 in the tail aligner 66 (Fig. 8). The shortest solder tails are connected to the lower terminals 26 and extend through holes 70 in the tail aligner 66. The solder tail of ground terminal 32 has a length between those of the upper terminals and lower terminals and extend through hole 72 in the tail aligner 66. In order to compensate for the resulting difference in path lengths, the tail aligner (Figs. 5 and 8) may include stepped portion 67. The stepped tail aligner 66 is dimensioned so as to balance the impedance of each line to a desired value. Figure 6 shows an alternate form of the invention in regard to the right-hand end or high frequency portion of electrical connector 10 described in relation to and in comparison to Figure 1. In Figure 6, the connector is designated 10′ and like numerals have been applied to designate like components in comparison to the embodiment of Figure 3. Similar but not identical components are designated with a " ′ ". More particularly, electrical connector 10′ also includes a common ground member, generally designated 20′ for surrounding ground contact 32 and electrically isolating contacts 26. Again, ground member 20′ provides a common ground plane to control impedance, emissions of radiation and cross-talk between the contacts. In this embodiment, it can be seen that the separate insulators 22 of the embodiment of Fig. 1 have been eliminated, and main dielectric housing 16′ extends entirely about the signal contacts 26. The housing 16′ is shown isolated in Figure 7. The housing has passages for 24′ for receiving the signal contacts 26. The interior of the passages may be similar to the configuration of passages 24 (Fig. 3) in insulators 22. In the embodiment of Figure 6, common ground member 20′ includes a central circular portion 28 (Fig. 9) surrounding ground contact 32, and four spoke portions 34 radiate outwardly from circular portion 28 between signal contacts 26. Openings 62 (Fig. 9) in member 20′ serve for cooperating with locking projections of the outer shield 18 similar to projections 59 of the Figs. 1-5 embodiment. As seen in Figure 7, housing 16′ has internal passage means 76 of a shape corresponding to the cross-section of the spoked portion of common ground member 20′. Although the ground member 20′ in the embodiment of Figure 6 does not completely surround signal contacts 26 as does ground member 20 (Fig. 1), the ground member 20′ is the closest conductor to each signal terminal 26 and therefore acts as the primary ground reference in order to control the impedance. It further isolates each of the signal contacts from the outer signal contacts. In addition, this embodiment has the advantage of using main housing 16′ as the insulating means surrounding the signal contacts 26 which simplifies the assembly of the conductor. It should be understood that in many applications, only three signal contacts 26 would be provided, such as the "red", "green" and "blue" signals to a video monitor. The passage in the fourth quadrant, for such applications, could be provided for other functions, such as a keying receptacle 80 (Fig. 10). Such passage could either be formed in the ground member 20′ or in the dielectric housing 16′. A plug (not shown) dimensioned to mate only with the keying receptacle is provided on the connector that mates with connector 10′. Figure 11 shows a further embodiment of the invention wherein an electrical connector 10″ (corresponding to connectors 10 and 10′) has the three high frequency signal contacts arranged in a vertically stacked array. Each contact is surrounded by a cylindrical insulator 82 which, in turn, is surrounded by a common conductive ground member 84 corresponding in function to the ground members 20 and 20′ in the embodiments of Figure 1 and 8, respectively. It can be seen that no separate ground contact (32 in Figs. 1 and 6) is incorporated in this embodiment. It will be understood by those skilled in the art that connectors 10, 10′ and 10″ will be utilized with similarly configured male connectors which are not described herein. It will further 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.

Claims: A generally rectangular, shielded electrical connector (10, 10′) for mating with another electrical connector along a mating axis (A), said shielded connector including a dielectric housing (16, 16′) having a mating face generally perpendicular to said mating axis and a face opposite said mating face, an outer conductive shield member (18) generally surrounding a region of said housing (10, 10′) for mating with said another electrical connector, a first portion (12) of said housing having mounted therein a plurality of first terminals (14) in a first given array for interconnection with a plurality of first terminals of said another electrical connector, and a second portion of said housing (10, 10′) having mounted therein a plurality of second terminals (26) in a second given array for interconnection with a plurality of second terminals of said another electrical connector, characterized in that a common conductive ground member (20, 20′) is mounted to said second portion of said housing (10, 10′) with portions (28, 34) of the ground member (20, 20′) disposed between the second terminals (26); and access means (76) adjacent said second portions of said housing (10, 10′) extend through an outer surface of said housing to permit insertion of said ground member (20, 20′) into said housing. The electrical connector of claim 1 wherein said common ground member (20) includes a portion (28) thereof having passage means (30) therethrough for receiving and surrounding a ground terminal (32). The electrical connector of claim 2 wherein said portion of the common ground member (20, 20′) for receiving the ground terminal (32) is located centrally of the common ground member (20, 20′). The electrical connector of claim 3 wherein said common ground member (20) includes a plurality of spoke-like portions (34) radiating outwardly of the ground terminal and disposed between respective adjacent ones of the second terminals (26). The electrical connector of claim 4 wherein said common ground member (20) has peripheral portions (34) joining the distal ends of the spoke-like portions whereby the common ground member surrounds each of the second terminals. The electrical connector of claim 1 wherein said housing (16) is a one-piece, molded member, said ground member (20) is a one-piece member and said access means (76) is a slot that permits insertion of said one-piece ground member along an axis generally parallel to said mating axis, through one of said faces and into said housing. The electrical connector of claim 6 wherein said common ground member (20) includes a portion thereof having passage means (30) therethrough for receiving and surrounding a ground terminal (32). The electrical connector of claim 6 wherein said outer conductive shield member (18) is mechanically and electrically connected to said conductive ground member (20). The electrical connector of claim 8 further comprising staking means (59) for mechanically and electrically securing the conductive ground member to the outer shield member (18).

Inventors: BRUNDER DAVID L, LOPATA JOHN E, BRUNDER, DAVID L., LOPATA, JOHN E.
Applicants: MOLEX INC, MOLEX INCORPORATED
Application year: 1992
Main classification: H01R13
IPC codes: H01R13, H01R12, H01R24