High density connector for balanced transmission lines

[0002] 1. Field of the Invention

[0003] The present invention relates generally to an electrical connecting device and, more particularly, to a connector used for high speed transmission lines. The present invention further relates to a connector assembly including such a connector. The present invention is effectively used for connecting balanced transmission lines.

[0004] 2. Description of the Related Art

[0005] Various types of connector systems used for connecting high speed transmission lines are well known in the art. One example of conventional connector systems for high speed transmission includes jack and plug connectors, each of which includes a plurality of signal contacts arranged in several rows in an electro-insulating body. In this type of conventional connector system or assembly, the signal lines structured by the mutually engaged contacts of the mutually assembled jack and plug connectors are partially shielded through the ground potential lines located between the rows of the signal contacts. To this end, each of the jack and plug connectors further includes a row of plural ground contacts arranged between the rows of signal contacts, which act as a shielding to reduce a crosstalk between the rows of signal contacts.

[0006] The above conventional connector assembly is effectively used for a single-ended transmission. However, this connector assembly cannot reduce a crosstalk between the signal lines arranged side by side in each row of contacts. Therefore, it is difficult to use this connector assembly for significantly high speed transmission, such as 1 gigabit/sec or more. Also, this structure of connector assembly makes it difficult to reduce a dimension of the insulator body and to increase the density of the signal lines.

[0007] Recently, a balanced data transmission system using balanced signals, that is, a differential data transmission system, has been developed for a high speed transmission, and it has been desired to provide a new connector system which can be effectively used for such a balanced data transmission.

[0008] It is therefore an object of the present invention to provide a connector which can be used for significantly high speed transmission.

[0009] It is another object of the present invention to provide a connector which can be effectively used for a balanced data transmission system.

[0010] It is further object of the present invention to provide a connector assembly including such a connector.

[0011] In accordance with the present invention, there is provided a connector, comprising: plural pairs of signal contact elements, the pairs being arranged parallel with each other in an array, and the signal contact elements of each of the pairs being arranged opposite to each other; plural ground contact elements, each of which is used as a shield to reduce a crosstalk between two parallel pairs of signal contact elements arranged side by side, the plural pairs of signal contact elements and the plural ground contact elements being alternately arranged in a row; and an electro-insulating body for supporting the signal contact elements and the ground contact elements in a mutually insulated arrangement.

[0012] In the preferred aspect of the present invention, the each pair of signal contact elements is used for a balanced transmission line.

[0013] It is advantageous that the profile of a portion of each of the ground contact elements substantially corresponds to a profile of the each pair of signal contact elements.

[0014] It is preferred that at least one of the ground contact elements is disposed at at least one of opposed outermost positions in the row.

[0015] It is also advantageous that the connector further comprises at least one shield plate disposed outside of the row to reduce crosstalk between the pairs of signal contact elements and the exterior of the connector.

[0016] Each pair of signal contact elements may define a jack-type contact pair, and each of the ground contact elements may define a jack contact.

[0017] Alternatively, the each pair of signal contact elements may define a plug-type contact pair, and each of the ground contact elements may define a plug contact.

[0018] It is also preferred that each of the signal contact elements includes a first contact end adapted to be slidably connected with a counterpart contact of another connector and a second contact end adapted to be fixedly connected with a signal line provided on a circuit board.

[0019] In this arrangement, the second contact end may extend parallel to the first contact end.

[0020] Alternatively, the second contact end may extend orthogonaly to the first contact end.

[0021] Each of the ground contact elements may include a first contact end adapted to be slidably connected with a counterpart contact of another connector and a second contact end adapted to be fixedly connected with a ground provided on a circuit board.

[0022] In this arrangement, the second contact end of the each ground contact element may extend parallel to the first contact end of the each ground contact element.

[0023] Alternatively, the second contact end of the each ground contact element may extend orthogonaly to the first contact end of the each ground contact element.

[0024] In this arrangement, the connector may further include a locator for holding second contact ends of the signal contact elements and of the ground contact elements at mutually spaced positions.

[0025] It is also preferred that each of the signal contact elements includes a first contact end adapted to be slidably connected with a counterpart contact of another connector and a second contact end adapted to be fixedly connected with a signal line provided in a cable.

[0026] In this arrangement, each of the ground contact elements may include a first contact end adapted to be slidably connected with a counterpart contact of another connector and a second contact end adapted to be fixedly connected with a ground provided in a cable.

[0027] In another aspect of the present invention, there is provided a connector assembly, comprising: a jack connector including: plural jack-type pairs of signal contact elements, the jack-type pairs being arranged parallel with each other in an array, and the signal contact elements of each of the jack-type pairs being arranged opposite to each other; plural jack-type ground contact elements, each of which is used as a shield to reduce crosstalk between two parallel jack-type pairs of signal contact elements arranged side by side, the plural jack-type pairs of signal contact elements and the plural jack-type ground contact elements being alternately arranged in a row; and a jack-type electro-insulating body for supporting the jack-type pairs of signal contact elements and the jack-type ground contact elements in a mutually insulated arrangement; a plug connector including: plural plug-type pairs of signal contact elements, the plug-type pairs being arranged parallel with each other in an array, and the signal contact elements of each of the plug-type pairs being arranged opposite to each other; plural plug-type ground contact elements, each of which is used as a shield to reduce crosstalk between two parallel plug-type pairs of signal contact elements arranged side by side, the plural plug-type pairs of signal contact elements and the plural plug-type ground contact elements being alternately arranged in a row; and a plug-type electro-insulating body for supporting the plug-type pairs of signal contact elements and the plug-type ground contact elements in a mutually insulated arrangement; and wherein each of the jack-type pairs of signal contact elements of the jack connector includes a contact end used to be slidably engaged with another contact end of each of the plug-type pairs of signal contact elements of the plug connector; and wherein each of the jack-type ground contact elements of the jack connector includes a contact end used to be slidably engaged with another contact end of each of the plug-type ground contact elements of the plug connector.

[0028] It is advantageous that the each jack-type pair of signal contact elements and each plug-type pair of signal contact elements are used for a balanced transmission line.

[0029] The above and other objects, features, and advantages of the present invention will become more apparent from the following description of preferred embodiments in connection with the accompanying drawings, in which:

[0030] FIG. 1 is a partial cross sectioned, perspective view of a connector assembly, in a separated state, according to a first embodiment of the present invention;

[0031] FIGS. 2A and 2B show a signal contact element of the jack connector of the connector assembly of FIG. 1;

[0032] FIG. 3 shows a ground contact element of the jack connector of the connector assembly of FIG. 1;

[0033] FIG. 4A is a plan view of an electro-insulating body of the jack connector of FIG. 1;

[0034] FIG. 4B is a sectional view taken along line b—b of FIG. 4A;

[0035] FIG. 4C is a sectional view taken along line c—c of FIG. 4A;

[0036] FIG. 5A is a sectional view for illustrating the assembling process of the jack connector of FIG. 1;

[0037] FIG. 5B is a sectional view for illustrating the assembling process of the jack connector of FIG. 1;

[0038] FIG. 6 is a perspective view of a signal contact element of the plug connector of the connector assembly of FIG. 1;

[0039] FIG. 7 is a perspective view of a ground contact element of the jack connector of the connector assembly of FIG. 1;

[0040] FIG. 8A is a plan view of an electro-insulating body of the jack connector of FIG. 1;

[0041] FIG. 8B is a sectional view taken along line b—b of FIG. 8A;

[0042] FIG. 8C is a sectional view taken along line c—c of FIG. 8A;

[0043] FIG. 9 is a sectional view for illustrating the assembling process of the plug connector of FIG. 1;

[0044] FIG. 10 is a sectional view of a connector assembly, in a separated state, according to a second embodiment of the present invention;

[0045] FIG. 11 shows two types of signal contact elements of the plug connector of the connector assembly of FIG. 10;

[0046] FIG. 12 shows a ground contact element of the plug connector of the connector assembly of FIG. 10;

[0047] FIG. 13A is a plan view of an electro-insulating body of the plug connector of FIG. 10;

[0048] FIG. 13B is a sectional view taken along line b—b of FIG. 13A;

[0049] FIG. 14 is a perspective view of a locator of the plug connector of FIG. 10;

[0050] FIG. 15 is a sectional view for illustrating the assembling process of the plug connector of FIG. 10;

[0051] FIG. 16 is a sectional view of a connector assembly, in a separated state, according to a third embodiment of the present invention;

[0052] FIG. 17A is a perspective view of a connector, according to another embodiment of the present invention; and

[0053] FIG. 17B is a sectional view of a cable.

[0054] Referring to the drawings, FIG. 2 shows a first embodiment of a connector assembly, according to the present invention, as a high density connector assembly used for high speed transmission. The connector assembly 3 is suitably used for connection between two circuit boards arranged parallel to each other. The connector assembly 3 includes a jack connector 31 and a plug connector 32, which are mounted on circuit boards 16, 17, respectively.

[0055] The jack connector 31 includes a plurality of jack-type pairs of signal contact elements 311, a plurality of jack-type ground contact elements 312 and a jack-type electro-insulating body 313. The plural pairs of signal contact elements 311 are arranged in parallel with each other in an array. Each pair of signal contact elements 311 defines a jack contact pair and is used for a balanced transmission line. The plural ground contact elements 312 are also arranged in parallel with each other in an array. The plural pairs of signal contact elements 311 and the plural ground contact elements 312 are alternately arranged in a single row. Each ground contact element 312 is used as a shield to reduce or suppress crosstalk between two pairs of signal contact elements arranged side by side in the row. The jack-type electro-insulating body 313 holds the jack-type pairs of signal contact elements 311 and the jack-type ground contact elements 312, as well as two opposed signal contact elements 311 of each pair, in a mutually insulated arrangement.

[0056] The plug connector 32 includes a plurality of plug-type pairs of signal contact elements 321, a plurality of plug-type ground contact elements 322 and a plug-type electro-insulating body 323. The plural pairs of signal contact elements 321 are arranged parallel with each other in an array. Each pair of signal contact elements 321 defines a plug contact pair and is used for a balanced transmission line. The plural ground contact elements 322 are also arranged parallel with each other in an array. The plural pairs of signal contact elements 321 and the plural ground contact elements 322 are alternately arranged in a single row. Each ground contact element 322 is used as a shield to reduce or suppress crosstalk between two pairs of signal contact elements 321 arranged side by side in the row. The plug-type electro-insulating body 323 holds the plug-type pairs of signal contact elements 321 and the plug-type ground contact elements 322, as well as two opposed signal contact elements 321 of each pair, in a mutually insulated arrangement.

[0057] Each signal contact element 311 (or a jack signal contact 311) of the jack connector 31 includes a contact end 311aused to be slidably engaged with a contact end 321aof each counterpart signal contact element 321 (or a plug signal contact 321) of the plug connector 32. Also, each ground contact element 312 (or a jack ground contact 312) of the jack connector 31 includes a contact end 312aused to be slidably engaged with a contact end 322aof each ground contact element 322 (or a plug ground contact 322) of the plug connector 32.

[0058] FIG. 2A shows a blank 311′ of the jack signal contact 311, prepared by a conventional press-stamping process, and FIG. 2B shows a detail of the jack signal contact 311 obtained from the blank 311′. A plurality of blanks 311′ are joined together by a connecting part 311″ into a comb shape. The jack signal contact 311 includes the contact end 311aformed along an edge of one end portion of the contact 311, which is curved convexly toward one lateral side of the contact 311, an intermediate, insulator engagement section 311badjacent to the contact end 311a, and an external terminal 311cadjacent to the section 311bat the other end of the contact 311. A narrow extension having the contact end 311aextends from the engagement section 311balong one lateral edge of the section 311b, and another narrow extension having the external terminal 311cextends oppositely from the engagement section 311balong the other lateral edge of the section 311b.

[0059] In the blank 311′, the external terminal 311cis joined to the connecting part 311″, and thus the contact 311 is formed by cutting off the external terminal 311cfrom the connecting part 311″. The engagement section 311bis provided at both lateral edges thereof with two pairs of bulges or projections 311b′, which act to fasten the engagement section 311bto the jack-type electro-insulating body 313 (or a jack insulator 313).

[0060] FIG. 3 shows a blank 312′ of the jack ground contact 312, prepared by a conventional press-stamping process. A plurality of blanks 312′ are joined together by a connecting part 312″ into a comb shape. The jack ground contact 312, obtained from the blank 312′, includes a pair of contact ends 312a, each of which has a same shape and structure as the contact end 311aof the jack signal contact 311 and thus is curved convexly toward the opposed contact, an intermediate, insulator engagement section 312badjacent to the contact ends 312a, which has a same size in a longitudinal direction of the contact as the insulator engagement section 311bof the jack signal contact 311, and a pair of external terminals 312cadjacent to the section 312b, each of which has a same shape as the external terminal 311cof the jack signal contact 311. Narrower extensions having the contact ends 312aextend from the engagement section 312balong both lateral edges of the section 312b, and narrower extensions having the external terminals 312cextend oppositely from the engagement section 312balong the both lateral edges of the section 312b.

[0061] In the blank 312′, the external terminals 312care joined to the connecting part 312″, and thus the contact 312 is formed by cutting off the external terminals 312cfrom the connecting part 312″. The engagement section 312bis provided at both lateral edges thereof with two-pairs of bulges or projections 312b′, which act to fasten the engagement section 312bto the jack insulator 313.

[0062] A distance “g” between two contact ends 312ais selected to be equal to a distance between two contact ends 311aof one pair of opposed jack signal contacts 311 inserted into opposed slits 313d(FIG. 4A) formed in the jack insulator 313. Also, the length of each extension having the contact end 312aand the length of each external terminal 312cof the jack ground contact 312 are substantially equal, respectively, to the length of extension having the contact end 311aand the length of external terminal 311cof the jack signal contact 311.

[0063] That is, in the jack connector 31, each of the ground contact elements 312 has a portion, a profile of which substantially corresponds to a profile of each pair of signal contact elements 311. Therefore, each ground contact element 312 can overlap two pairs of signal contact elements 311 arranged side by side in the row in the jack insulator 313, and thus acts as a shield to reduce or suppress crosstalk between the two pairs of signal contact elements 311.

[0064] FIGS. 4A to 4C show the jack insulator 313 in a plan view, a b—b section and a c—c section, respectively. The jack insulator 313 is shaped as a bottomed box provided with a peripheral wall 313ahaving a height slightly larger than the length of each extension for the contact end 311a, 312aof the jack signal contact 311 and the jack ground contact 312. On the longitudinal, inner opposed surfaces of the peripheral wall 313a, a plurality of grooves 313b, extending from the open end to the inner surface of the bottom wall of the insulator 313, are formed in parallel to and oppositely aligned to each other in a pitch “p/2” i.e. half the pitch “p” of the plural pairs of the jack signal contact 311.

[0065] In the bottom wall of the insulator 313, a plurality of slits 313c, 313dare formed to penetrate the bottom wall and to be aligned with the respective grooves 313b. Each slit 313c, 313dhas a same thickness as the each groove 313b, and the thickness of each of the slits 313c, 313dand grooves 313bis slightly larger than the thickness of each of the jack signal and ground contacts 311, 312. Each of the larger slits 313cextends laterally between opposed grooves 313band can fixedly receive the engagement section 312bof the jack ground contact 312, and each of the smaller slits 313dextends laterally from respective one of remaining grooves 313bto a midway of the bottom wall and can fixedly receive the engagement section 311bof the jack signal contact 311. The plural larger slits 313cand the plural pairs of opposed smaller slits 313dare alternately arranged in a row.

[0066] As shown in FIGS. 5A and 5B, the plural pairs of jack signal contacts 311 are inserted into the respective slits 313d, in such an arrangement that the contact ends 311aof each pair are opposed to each other, with the contact ends 311abeing leading ends in a direction shown by an arrow E₁, and the engagement sections 311bare press-fit in the slits 313d. Also, the plural jack ground contacts 312 are inserted into the respective slits 313cwith the contact ends 312abeing leading ends in a direction shown by an arrow E₂, and the engagement sections 312bare press-fit in the slits 313c.

[0067] When the jack ground contacts 312 are fastened into the respective slits 313cand the jack signal contacts 311 are fastened into the respective slits 313d, the contact ends 311aof the jack signal contacts 311 are aligned with each other in the longitudinal direction of the jack insulator 313.

[0068] In the jack connector 31 of the first embodiment assembled in this manner, the contact ends 311aof the jack signal contacts 311 and the contact ends 312aof the jack ground contacts 312 are aligned with each other in the direction of the row of these contacts 311, 312 while maintaining the distance “g” between the opposed pair of contact ends 311a, 312a. On the other hand, the external terminals 311cof the jack signal contacts 311 and the external terminals 312cof the jack ground contacts 312 are arranged in a staggered manner in four separate rows of the terminals 311c, 312c.

[0069] The circuit board 16 (FIG. 1) is provided with a plurality of through holes 16ain an array corresponding to the staggered array of the terminals 311c, 312c. Accordingly, it is possible to mount the jack connector 31 on the surface of the circuit board 16 by inserting the terminals 311c, 312cinto the respective through holes 16a. Then, the terminals 311cof the jack signal contacts 311 are fixedly connected with signal lines provided on the circuit board 16, and the terminals 312cof the jack ground contacts 312 are fixedly connected with a ground provided on the circuit board 16.

[0070] FIG. 6 shows a detail of the plug signal contact 321, prepared by a conventional press-stamping and bending process. The plug signal contact 321 includes the contact end 321aformed on a flat surface of one end portion of the contact 321, an intermediate insulator engagement section 321badjacent to the contact end 321a, and an external terminal 321cadjacent to the section 321bat the other end of the contact 321. An extension having the contact end 321aextends from the engagement section 321bparallel to the section 321b, and another extension having the external terminal 321cextends oppositely from the engagement section 321borthogonally to the section 321b.

[0071] The plug signal contact 321 has a constant lateral size throughout the entire length thereof, which is larger than the thickness of the jack signal contact 311. Also, the extension having the contact end 321ahas a length shorter than the length of the extension having the contact end 311aof the jack signal contact 311. The engagement section 321bis provided at both lateral edges thereof with two bulges or projections 321b′, which act to fasten the engagement section 321bto the plug-type electro-insulating body 323 (or a plug insulator 323).

[0072] FIG. 7 shows a detail of the plug ground contact 322, prepared by a conventional press-stamping and bending process from a blank material thicker than that of the jack ground contact 312. The plug ground contact 322 includes a pair of contact ends 322aformed along opposed lateral edges of one end portion of the contact 322, an intermediate insulator engagement section 322badjacent to the contact ends 322a, which has a same size in a longitudinal direction of the contact as the insulator engagement section 321bof the plug signal contact 321, and an external terminal 322cadjacent to the section 322b. An extension having the contact ends 322aextends from the engagement section 322bparallel to the section 322b, and the external terminal 322cis formed as a pad on the lower edge of the engagement section 322b. The engagement section 322bis provided at both lateral edges thereof with two pairs of bulges or projections 322b′, which act to fasten the engagement section 322bto the plug insulator 323.

[0073] A lateral distance between two contact ends 322ais selected to be equal to a distance between two contact ends 321aof one pair of opposed plug signal contacts 321 inserted into opposed slits 323d(FIG. 8A) formed in the plug insulator 323. Also, the length of the extension having the contact ends 322ais substantially equal to the length of extension having the contact end 321aof the plug signal contact 321.

[0074] That is, in the plug connector 32, a portion of a profile of each of the ground contact elements 322 substantially corresponds to a profile of each pair of signal contact elements 321. Therefore, each ground contact element 322 can overlap two pairs of signal contact elements 321 arranged side by side in the row in the plug insulator 323, and thus acts as a shield to reduce or suppress crosstalk between the two pairs of signal contact elements 321.

[0075] FIGS. 8A to 8C show the plug insulator 323 in a plan view, a b—b section and a c—c section, respectively. The plug insulator 323 is shaped as a bottomed box provided with a peripheral wall 323ahaving a height slightly larger than the length of each extension for the contact end 321a, 322aof the plug signal contact 321 and the plug ground contact 322. The peripheral wall 323ahas an inner surface capable of fitting with the outer surface of the peripheral wall 313aof the jack insulator 313.

[0076] In the bottom wall of the plug insulator 323, a plurality of slits 323bare formed to penetrate the bottom wall and to be aligned with the respective slits 313cof the jack insulator 313 when the plug insulator 323 is fitted with the jack insulator 313 under an interengagement between the peripheral walls 323aand 313a. Each slit 323bextends laterally in a center region of the bottom wall of the plug insulator 323 and can fixedly receive the engagement section 322bof the plug ground contact 322.

[0077] Also, in the center region of the bottom wall of the plug insulator 323, a plurality of partition walls 323cis formed to project from the bottom wall and to be aligned with the respective slits 313dof the jack insulator 313 when the plug insulator 323 is fitted with the jack insulator 313. Each partition wall 323chas a height slightly lower than that of the peripheral wall 323aand a lateral size slightly smaller than that of the slit 323b. On both lateral sides of each partition wall 323c, slits 323dare formed to penetrate through the bottom wall. Each slit 323dcan fixedly receive the engagement section 321bof the plug signal contact 321. The plural slits 323cand the plural pairs of opposed slits 323dare alternately arranged in a row.

[0078] As shown in FIG. 9, the plural pairs of plug signal contacts 321 are inserted into the respective slits 323d, in such an arrangement that the extensions having the contact ends 321aof each pair are abutted onto the opposed side faces of the partition wall 323cand the external terminals 321cof each pair extend away from each other, with the contact ends 321abeing leading ends in a direction shown by arrows F₁, and the engagement sections 321bare press-fit in the slits 323d. Also, the plural plug ground contacts 322 are inserted into the respective slits 323bwith the contact ends 322abeing leading ends in a direction shown by an arrow F₂, and the engagement sections 322bare press-fit in the slits 323b.

[0079] When the plug ground contacts 322 are fastened into the respective slits 323cand the plug signal contacts 321 are fastened into the respective slits 323d, the contact ends 321aof the plug signal contacts 321 are aligned with each other in the longitudinal direction of the plug insulator 323, and the contact ends 322aof the plug ground contacts 322 are located between and parallel to the partition wall 323c. In the plug connector 32 of the first embodiment assembled in this manner, the contact ends 321aof the plug signal contacts 321 and the contact ends 322aof the plug ground contacts 322 are aligned with each other in the direction of the row of these contacts 321, 322 while maintaining the distance between the opposed pair of contact ends 321a, 322a. On the other hand, the external terminals 321cof the plug signal contacts 321 and the external terminals 322cof the plug ground contacts 322 are arranged, in a staggered manner, in three separate rows of the terminals 321c, 322c.

[0080] The circuit board 17 (FIG. 1) is provided with a plurality of signal electrodes 17aand a single ground electrode 17bin an array corresponding to the staggered array of the terminals 321c, 322c. Accordingly, it is possible to mount the plug connector 32 on the surface of the circuit board 17 by putting the terminals 321c, 322conto the respective electrodes 17a, 17b. Then, the terminals 321cof the plug signal contacts 321 are fixedly connected with signal electrodes 17aprovided on the circuit board 17, and the terminals 322cof the plug ground contacts 322 are fixedly connected with a ground electrode 17bprovided on the circuit board 17.

[0081] When the plug connector 32 is suitably fitted with the jack connector 31 as shown by an arrow D in FIG. 1, it is possible to provide the high-speed transmission connector assembly 3, wherein the plural pairs of plug signal contacts 321 of the plug connector 32 are connected with the corresponding, plural pairs of jack signal contacts 311 of the jack connector 31, to define plural pairs of signal transmission contact lines, and the plural plug ground contacts 322 of the plug connector 32 are connected with the plural jack ground contacts 312 of the jack connector 31, to define plural ground contact lines.

[0082] In such a high-speed transmission connector assembly 3, each ground contact line, structured from the mutually connected jack and plug ground contacts 312, 322, is interposed as a shield between two pairs of signal transmission contact lines, structured from the mutually connected jack and plug signal contacts 311, 321, arranged side by side in the row of contacts, and thereby it is possible to reduce or suppress the crosstalk between the two pairs of signal transmission contact lines. Also, it is possible to eliminate the crosstalk between the laterally opposed signal transmission contact lines of each pair, by connecting these opposed signal transmission contact lines with a balanced transmission line, since the balanced transmission line causes a virtual ground plane between a pair of signal lines used therefor.

[0083] FIG. 10 illustrates a second embodiment of a connector assembly, according to the present invention, as a high density connector assembly used for high speed transmission. The connector assembly 4 is suitably used for connection between two circuit boards arranged orthogonal to each other. The connector assembly 4 includes a jack connector 31 and a plug connector 42, which are mounted on circuit boards 16, 18, respectively.

[0084] In this embodiment, the jack connector 31 and the circuit board 16 have a structure identical to those in the first embodiment, and thus the description thereof is not repeated.

[0085] The plug connector 42 includes a plurality of plug-type pairs of right-angled signal contact elements 421, a plurality of plug-type right-angled ground contact elements 422 and a plug-type electro-insulating body 423. The plural pairs of signal contact elements 421 are arranged parallel with each other in an array. Each pair of signal contact elements 421 defines a plug contact pair and is used for a balanced transmission line. The plural ground contact elements 422 are also arranged parallel with each other in an array. The plural pairs of signal contact elements 421 and the plural ground contact elements 422 are alternately arranged in a single row. Each ground contact element 422 is used as a shield to reduce or suppress crosstalk between two pairs of signal contact elements 421 arranged side by side in the row. The plug-type electro-insulating body 423 holds the plug-type pairs of signal contact elements 421 and the plug-type ground contact elements 422, as well as two opposed signal contact elements 421 of each pair, in a mutually insulated arrangement.

[0086] Each signal contact element 421 (or a plug signal contact 421) includes a contact end 421aand an insulator engagement section 421b, both having the same structure of the contact end 321aand the insulator engagement section 321b, respectively, of the plug signal contact 321 of the first embodiment. Also, each ground contact element 422 (or a plug ground contact 422) of the plug connector 42 includes contact ends 422aand an insulator engagement section 422b, both having the same structure of the contact ends 322aand the insulator engagement section 322b, respectively, of the plug ground contact 322 of the first embodiment. The description of these same or similar structures of the contacts 421, 422 are not repeated.

[0087] FIG. 11 shows a detail of the right-angled plug signal contact 421, prepared by a conventional press-stamping and bending process. The right-angled plug signal contact 421 includes the contact end 421a, the insulator engagement section 421b, and an extension 421dadjacent to the section 421band bent at a right angle to define an external terminal 421cat the other end of the contact 421. The contact end 421aextends parallel to the section 421b, and the external terminal 421cextends orthogonally to the section 421b. Each pair of plug signal contacts 421 includes a shorter one 421-1 having a shorter extension 421dand a longer one 421-2 having a longer extension 421d.

[0088] The right-angled plug signal contact 421 has a constant lateral size throughout the entire length thereof, which is larger than the thickness of the jack signal contact 311. Also, the extension having the contact end 421ahas a length shorter than the length of the extension having the contact end 311aof the jack signal contact 311.

[0089] FIG. 12 shows a detail of the right-angled plug ground contact 422, prepared by a conventional press-stamping and bending process from a blank material thicker than that of the jack ground contact 312. The right-angled plug ground contact 422 includes the pair of contact ends 422a, the insulator engagement section 422b, and an extension 422dadjacent to the section 422band having a pair of external terminals 422cextend at a right angle from one lateral side of the section 422b. The contact end 422aextends parallel to the section 422b, and the external terminals 422cextend orthogonally to the section 422b.

[0090] A lateral distance between two contact ends 422ais selected to be equal to a distance between two contact ends 421aof one pair of opposed plug signal contacts 421 inserted into opposed slits 423d(FIG. 13A) formed in the plug-type electro-insulating body 423 (or a plug insulator 423). Also, the length of the extension having the contact ends 422ais substantially equal to the length of the extension having the contact end 421aof the plug signal contact 421.

[0091] That is, in the plug connector 42, a portion of the profile of each of the ground contact elements 422 substantially corresponds to a profile of each pair of signal contact elements 421. Therefore, each ground contact element 422 can overlap two pairs of signal contact elements 421 arranged side by side in the row in the plug insulator 423, and thus acts as a shield to reduce or suppress crosstalk between the two pairs of signal contact elements 421.

[0092] FIGS. 13A and 13B show the plug insulator 423 in a plan view and a b—b section, respectively. The plug insulator 423 has generally the same structure as the plug insulator 323 of the first embodiment, except that an extension wall 423eis added to the upper section identical to the plug insulator 323. The extension wall 423eextends from the bottom wall of the upper section along three edges of the bottom wall, and acts to cover the right-angled extensions 421d, 422dof the signal and ground contacts 421, 422 held in positions in the plug insulator 423. The description of the same or similar structures of the plug insulator 423 are not repeated.

[0093] The plug connector 42 further includes a locator 424 for positioning and holding the external terminals 421c, 422cof the right-angled plug signal and ground contacts 421, 422 at mutually spaced positions. As shown in FIG. 14, the locator 424 is shaped as a flat rectangular plate and is mounted to the extension wall 423eof the plug insulator 423 along the remaining edge of the bottom wall of the insulator 423. The locator 424 is provided with a plurality of holes 424aat positions corresponding to the external terminals 421c, 422cof the right-angled plug signal and ground contacts 421, 422, both incorporated into the plug insulator 423. Each terminal hole 424ahas a dimension allowing the external terminal 421c, 422cto be somewhat loosely inserted into the same.

[0094] As shown in FIG. 15, the plural pairs of right-angled plug signal contacts 421-1, 421-2 are inserted into the respective slits 423dof the plug insulator 423, in such an arrangement that the extensions having the contact ends 421aof each pair abut the opposed side faces of the partition wall 423cand the external terminals 421cof each pair are extend in the same direction, with the contact ends 421abeing leading ends in a direction shown by arrows H₁, H₂, and the engagement sections 421bare press-fit in the slits 423d. Also, the plural right-angled plug ground contacts 422 are inserted into the respective slits 423bwith the contact ends 422abeing leading ends in a direction shown by an arrow H₃, and the engagement sections 422bare press-fit in the slits 423b.

[0095] When the plug ground contacts 422 are fastened into the respective slits 423cand the plug signal contacts 421-1, 421-2 are fastened into the respective slits 423d, the contact ends 421aof the plug signal contacts 421 are aligned with each other in the longitudinal direction of the plug insulator 423, and the contact ends 422aof the plug ground contacts 422 are located between, and parallel to, the partition wall 423c. In the plug connector 42 of the second embodiment assembled in this manner, the contact ends 421aof the plug signal contacts 421 and the contact ends 422aof the plug ground contacts 422 are aligned with each other in the direction of the row of these contacts 421, 422 while maintaining a distance between the opposed pair of contact ends 421a, 422a. On the other hand, the external terminals 421cof the plug signal contacts 421 and the external terminals 422cof the plug ground contacts 422 are arranged in a staggered manner in four separate rows of the terminals 421c, 422c.

[0096] Then, the locator 424 is mounted to the plug insulator 423 as shown by an arrow H₄at a position for enabling the holes 424aof the locator 424 to receive the right-angled terminals 421c, 422c. In this manner, it is possible to obtain the plug connector 42 as shown in FIG. 10, wherein the external terminals 421bof the plug signal contacts 421 and the external terminals 422bof the plug ground contact 422bare arranged and positioned in a staggered manner.

[0097] The circuit board 18 (FIG. 10) is provided with a plurality of through holes 18ain an array corresponding to the staggered array of the terminals 421c, 422c. Accordingly, it is possible to mount the plug connector 42 on the surface of the circuit board 18 by inserting the terminals 421c, 422cinto the respective through holes 18a. Then, the terminals 421cof the plug signal contacts 421 are fixedly connected with signal lines provided on the circuit board 18, and the terminals 422cof the jack ground contacts 422 are fixedly connected with a ground provided on the circuit board 18.

[0098] When the plug connector 42 is suitably fitted with the jack connector 31 as shown by an arrow G in FIG. 10, it is possible to provide the high-speed transmission connector assembly 4, wherein the plural pairs of plug signal contacts 421 of the plug connector 42 are connected with the corresponding plural pairs of jack signal contacts 311 of the jack connector 31, to define plural pairs of signal transmission contact lines, and the plural plug ground contacts 422 of the plug connector 42 are connected with the plural jack ground contacts 312 of the jack connector 31 to define plural ground contact lines.

[0099] In such a high-speed transmission connector assembly 4, each ground contact line, structured from the mutually connected jack and plug ground contacts 312, 422, is interposed as a shield between two pairs of signal transmission contact lines, structured from the mutually connected jack and plug signal contacts 311, 421, arranged side by side in the row of contacts, and thereby it is possible to reduce or suppress the crosstalk between the two pairs of signal transmission contact lines. Also, it is possible to eliminate the crosstalk between the laterally opposed signal transmission contact lines of each pair, by connecting these opposed signal transmission contact lines with a balanced transmission line, since the balanced transmission line causes a virtual ground plane between the pair of signal lines used therefor.

[0100] FIG. 16 illustrates a third embodiment of a connector assembly, according to the present invention, as a high density connector assembly used for high speed transmission. The connector assembly 5 is suitably used for connection between two circuit boards arranged parallel to each other. The connector assembly 5 includes a jack connector 51 and a plug connector 52, which are mounted on circuit boards 19, 20, respectively.

[0101] In this embodiment, the jack connector 51 and the circuit board 19 have a similar structure to those in the first embodiment, except that separate shielding plates are provided in the jack connector 51. Also, the plug connector 52 and the circuit board 20 have a similar structure to those in the first embodiment, except that separate shielding plates are provided in the plug connector 52. The description of the similar portion is not repeated.

[0102] The jack connector 51 of the third embodiment has a pair of first shield plates 514 attached to the respective lateral outer surfaces of the peripheral wall 313aof the jack insulator 313. The first shield plates 514 extend alongside the row of the contacts 311, 312 over the entire area of the lateral outer surfaces. The first shield plates 514 may be bonded to the outer surfaces of the jack insulator 313 by, e.g., an adhesive. Each shield plate 514 has a plurality of tongues 514bextending from an edge 514athereof towards the circuit board 19 and a plurality of small projections 514cformed on an outer surface thereof.

[0103] The circuit board 19 is provided with a plurality of through holes 19ain an array corresponding to the staggered array of the terminals 311c, 312c(FIGS. 5A, 5B). The circuit board 19 is also provided with holes 19bconnected to a ground voltage, at positions corresponding to the tongues 514bof the first shield plates 514. Accordingly, it is possible to mount the jack connector 51 on the surface of the circuit board 19 by inserting the terminals 311c, 312cinto the respective through holes 19a, and also inserting the tongues 514binto the respective holes 19b. Then, the terminals 311cof the plug signal contacts 311 are fixedly connected with signal lines provided on the circuit board 19, and the terminals 312cof the jack ground contacts 312 as well as the tongues 514bof the first shield plates 514 are fixedly connected with a ground provided on the circuit board 19.

[0104] The plug connector 52 of the third embodiment has a pair of second shield plates 524 attached onto the respective lateral inner surfaces of the peripheral wall 323aof the plug insulator 323. The second shield plates 524 extend alongside the row of the contacts 321, 322 over the entire area of the lateral inner surfaces. The second shield plates 524 may be bonded to the inner surfaces of the plug insulator 323 by, e.g., an adhesive. Each shield plate 524 has a plurality of tongues 524bextending from an edge 524athereof and penetrating though the bottom wall of the plug insulator 323.

[0105] The circuit board 20 is provided with a plurality of signal electrodes 20aand ground electrodes 20bin an array corresponding to the staggered array of the terminals 321c, 322c(FIG. 9). The circuit board 20 is also provided with holes 20c, connected to a ground voltage, at positions corresponding to the tongues 524bof the second shield plates 524. Accordingly, it is possible to mount the plug connector 52 on the surface of the circuit board 20 by putting the terminals 321c, 322conto the respective electrodes 20a, 20b, and inserting the tongues 524binto the respective holes 20c. Then, the terminals 321cof the plug signal contacts 321 are fixedly connected with signal electrodes 20aprovided on the circuit board 20, the terminals 322cof the plug ground contacts 322 are fixedly connected with a ground electrodes 20bprovided on the circuit board 20, and tongues 524bof the second shield plates 524 are fixedly connected with the holes 20c.

[0106] When the plug connector 52 is suitably fitted with the jack connector 51 as shown by an arrow I in FIG. 16, it is possible to provide the high-speed transmission connector assembly 5, wherein the plural pairs of plug signal contacts 321 of the plug connector 52 are connected with the corresponding, plural pairs of jack signal contacts 311 of the jack connector 51, to define plural pairs of signal transmission contact lines, and the plural plug ground contacts 322 of the plug connector 52 are connected with the plural jack ground contacts 312 of the jack connector 51, to define plural ground contact lines. Also, in this embodiment, when the plug connector 52 is suitably fitted with the jack connector 51, the first shield plates 514 are connected with the second shield plates 524 through the projections 514cto define a frame ground surrounding the row of the contact lines.

[0107] In such a high-speed transmission connector assembly 5, each ground contact line, structured from the mutually connected jack and plug ground contacts 312, 322, is interposed as a shield between two pairs of signal transmission contact lines, structured from the mutually connected jack and plug signal contacts 311, 321, arranged side by side in the row of contacts, and thereby it is possible to reduce or suppress the crosstalk between the two pairs of signal transmission contact lines. Also, it is possible to eliminate the crosstalk between the laterally opposed signal transmission contact lines of each pair, by connecting these opposed signal transmission contact lines with a balanced transmission line, since the balanced transmission line causes a virtual ground plane between the pair of signal lines used therefor.

[0108] Further, it is possible to eliminate the crosstalk between all the signal transmission contact lines and the exterior of the connector assembly 5 by the frame ground structured from the first and second shield plates 514, 524. In this respect, it is preferred that the ground contact line, structured from the mutually connected jack and plug ground contacts 312, 322, is disposed at respective one of opposed outermost positions in the row of the contact lines.

[0109] Such shield plates used for the frame ground may also be incorporated into the connector assembly 4 of the second embodiment. In this case, it is apparent that the same effect as in the connector assembly 5 may be obtained.

[0110] FIG. 17A shows another embodiment of a connector, according to the present invention, as a high density connector used for high speed transmission. The connector 62 of this embodiment is suitably used for connection of a balanced transmission cable 63. The structure and function of the connector 62 are similar to those of the plug connectors of the above embodiments, and are not described in detail. The connector 62 may be fixed to the cable 63 by a resinous mold 64.

[0111] As shown in FIG. 17B, the balanced transmission cable 63 includes plural balanced transmission lines 65, plural grounds 66 respectively surrounding each balanced transmission line (or a line pair) 65, a shield 67 enclosing all the balanced transmission lines 65 and grounds 66, and a sheath 68 surrounding the shield 67. The signal contact elements of the connector 62 are fixedly connected with the respective balanced transmission lines 65, and the ground contact elements of the connector 62 are fixedly connected with the respective grounds 66.

[0112] In the above embodiments of the high speed transmission connectors, the signal contact elements are arranged in two rows. However, the present invention should not be limited thereto, but may be applied to any other connectors having an even number of rows of signal contact elements.

[0113] While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention. The scope of the invention is therefore to be determined solely by the appended claims.