CN1099738C - Electrical connector with enhanced grounding characteristics - Google Patents

Abstract

An electrical connector 1 having enhanced grounding characteristics utilizes an insulating housing 2 with a plurality of conductive terminals 3 mounted inside, and a metal grounding shield 4 covering the connector housing. The grounding shield has at least one grounding lead piece 9 formed integrally therewith and bent inward. The grounding lead extends into contact with a selected terminal inside of the connector to thereby function as a grounding terminal to provide a convenient grounding path in close proximity to the grounding circuit when high-frequency current signals are induced in the grounding shield.

Description

Electrical connectors with reinforced grounding characteristics

This invention relates generally to electrical connectors, and more particularly to electrical connectors having enhanced grounding characteristics suitable for use in high frequency circuits.

Electrical connectors are commonly used to join printed circuit boards together. In the construction of such connectors, it is known to use metal shields around the insulating case in order to prevent leakage of high frequency signals from the printed circuit board or the joints where the associated electrical parts are connected together. Examples of high frequency connectors using metal shields are disclosed in Japanese Patent Application Laid-open Nos. 4-255678 and 5-217630. These high frequency connectors utilize an insulated box with multiple terminals secured inside the box and a metal shield secured outside the box. The connector design utilizes the metal shield so that any high frequency signal present on any terminal is grounded. The inner terminal, the outer shield and the insulating box in the middle are combined to act as a capacitor, and capacitive coupling occurs to transmit the high-frequency signal from the terminal to the ground shield.

However, there is concern that in this type of structure, the local high-frequency channel that appears between the terminal and the metal shield acts as an antenna, causing high-frequency signals to be emitted to adjacent terminals. In order to avoid interference between terminals arranged along opposite length sides of the connector when carrying high-frequency signals as much as possible, the outer metal shield is grounded at opposite ends of the connector. However, as the length of the connector increases and the number of terminals extending along the length of the connector increases, the likelihood of antenna interaction between the metal shield and the terminals also increases. The increase in connector size and the increase in the number of terminals increases the likelihood of inducting unwanted signals as the ground end of the connector moves farther from the high-frequency terminal and as high-frequency signals seek a low-frequency path. Impedance paths to ground, they tend to propagate through nearby terminals, and through the circuitry of the printed circuit board, rather than through the ground path at the end of the connector.

The purpose of the present invention is to improve the connector so that it avoids the disadvantages mentioned above and by increasing the number of ground paths along the length of the connector, it reduces the antenna effect which may cause high frequency signal emission.

It is an object of the present invention to provide an electrical connector having enhanced grounding characteristics for high frequency signals.

Another object of the present invention is to provide an electrical connector having an insulating housing, an internal recess for receiving a plurality of conductive terminals along its length, and an external ground shield having a plurality of ground connections , extending to contact the select terminal of the connector, thus increasing the number of ground paths along the length of the connector.

Still another object of the present invention is to provide an electrical connector, which has a connector body made of insulating material, longitudinal grooves are arranged in the connector body, and a plurality of terminals are arranged in the grooves in sequence spaced apart from each other, and has a solder tail portion that extends to the outside of the connector body portion, a metal ground shield is disposed on the outside of the connector body, the ground shield has a plurality of ground terminals spaced from each other along the length of the connector, and it extends inwardly , through the contact of the connector body and selected connector terminals, thereby defining a series of grounding channels arranged along the length of the connector.

To achieve these and other objects, the present invention provides an electrical connector having an elongated connector housing made of insulating material, the housing having a groove extending lengthwise between its inner facing end faces, The recess of the housing is at least partially defined by a pair of side walls of the connector, a plurality of conductive terminals are arranged along facing inner surfaces of the side walls of the connector, and a metallic ground shield is disposed on the outer surface of the connector , which is centered with the terminals, wherein: at least one of the conductive terminals is a ground terminal, and the connector housing includes at least one hole formed in a side wall thereof, the at least one hole is grounded with the connector In the terminal pair, the ground shield has a body portion having a window-like U-shaped opening formed therein defining at least one ground lead, the connector housing aperture being centered with the at least one ground lead And oppositely, the at least one grounding lead has a free end and a tail end defined in the window-like U-shaped opening, the tail end of the grounding lead is integrally formed with the body part of the ground shield, and the grounding lead A free end defines a ground path between the ground shield and the ground terminal by extending through the connector housing aperture and in electrical contact with the ground terminal of the connector terminal.

The invention is equally applicable to any surface mount connector such as plug or socket type connector elements as well as circuit board connectors, edge board connectors and the like.

In an electrical connector constructed in accordance with the principles of the present invention, the selective terminal contacting the metal shield lead can be used as a ground terminal, thus allowing any high frequency current induced in the metal shield to propagate along the shortest possible path to the associated ground circuit. Therefore, when a high-frequency current is induced in the metal shield, the antenna effect that may locally occur therein can be greatly reduced, so that undesired transmission of high-frequency signals through other terminals can be prevented.

These and other objects, features and advantages of the present invention will be clearly understood from the following detailed description.

In the following detailed description, reference will be made to the accompanying drawings in which like reference numerals indicate like parts:

1 is a cross-sectional view of a connector element such as a plug connector constructed in accordance with the principles of the present invention;

Fig. 2 is the sectional view of another kind of connector element such as receptacle connector that constitutes according to the principle of the present invention;

Figure 3 is an enlarged cross-sectional view of a connector assembly utilizing two interengaging connector elements constructed in accordance with the principles of the present invention, wherein one connector element is a pin connector constructed in accordance with the principles of the present invention and the other connects The device element is a conventional socket connector;

Figure 4 is a front view of the plug connector element of the electrical connector assembly of Figure 3;

Figure 5 is a front view of the receptacle connector element of the electrical connector assembly of Figure 3;

6 is a schematic diagram of a prior art grounding connector;

FIG. 7 is a schematic diagram of the connector in FIG. 3 .

Referring now to FIG. 1, there is shown a cross-sectional view of a plug connector 1 with enhanced grounding characteristics formed in accordance with the principles of the present invention, which includes an elongated insulating outer box 2 with a pair of outer box side walls 5 defined therein. The internal groove 50. Recess 50 is sized to receive opposing interengaging connector elements and, in other embodiments, circuit cards to be received therein. A plurality of terminals 3 are arranged at regular intervals along the length direction on the facing inner surface 54 of the connector side wall 5 . A conductive shield 4 , preferably a metal shield, surrounds the side wall 5 of the connector housing 2 .

The terminals 3 each include a contact portion 3b which is located in a recess 50 and extends vertically from the middle body portion 3a of the terminal 3 to near the top of the recess 50 . The solder tail portion 3c extends outwardly from the central body portion 3a in a horizontal manner out of the connector 1 so as to enable the connector 1 to be mounted on an associated stationary flat panel, such as a circuit board 60, wherein the solder tail portion 3c is facing , engages on the contact pads 62 of the circuitry of the circuit board 60.

An important aspect of the present invention is that the connector housing 2 has a series of holes 7, preferably slot-shaped, formed therein. These holes 7 can be located on any side wall of the connector, or located at the base or body part of the connector housing 2, and are aligned with some prescribed terminals 3, for example every fifth or tenth alignment. The metallic ground shield 4 has a series of respective ground leads 9 formed along the horizontal extension 8 of the shield, each such ground lead 9 being preferably stamped and formed in the form of a window in the horizontal body portion 8 of the shield 4. The opening 61 (shown in FIG. 4 as having a U-shape). The opening 61 defines a facing free end 64 and a tail end 66 of each ground lead 9 . The grounding leads 9 are integrally attached to the grounding shield 4, their free ends 64 are not attached thereto, so that they can be easily formed, such as bent inwards and placed, in contact with selected associated terminals 3, Fig. 1 The contact shown in FIG. 2 occurs between the body portion 3 a of the terminal 3 and the contact portion 68 formed on the free end portion 64 of the ground lead 9 .

Referring now to FIG. 2, there is shown a receptacle connector 11 having enhanced grounding features constructed in accordance with the principles of the present invention. According to one embodiment, it comprises an elongated insulating housing 12 with a plurality of terminals 13 arranged at regular intervals along the length on facing inner surfaces of connector side walls 15 of the housing 12 . A metallic conductive shield 14 surrounds the wall 15 of the connector housing 12 . Terminal 13 includes contact portion 13b, which extends vertically inside receptacle connector groove 70, body portion 13a, which is embedded in connector housing 12, and solder tail portion BC, which extends through base 16 of connector housing 12 , separated from here to provide the mating plate on which the connector can be mounted to the printed circuit board, similar to the mounting method shown in Figure 1.

An optional terminal cutout in the form of a through hole 17 is formed in the body portion 18 of the connector 11 , providing an opening to allow a ground lead 19 to extend therethrough to contact the internal conductive terminal 13 of the connector 1 . The metal shield 14 has a plurality of ground leads 19 punched and bent inwardly so that they pass through the holes 17 to resiliently contact the middle portion 13a of the connector terminal 13 by the free ends 19a of the ground leads 19 . Such contact establishes an electrical connection between the metal ground shield 14 and the select terminal 13 .

In operation, the select terminals 3, 13 of the connector elements 1, 11 and the associated ground leads 9, 19 of the ground shields 4, 14 are in contact as ground terminals. These terminals 3 , 13 are connected to the ground circuit of the associated printed circuit board 60 on which the connector elements are mounted. When high-frequency signals are transmitted through certain terminals of the connector elements 1, 11, capacitive coupling occurs between these terminals and the outer metal shields 4, 14 separated from the terminals by a certain distance, and the signal "jumps" over the insulating The outer box 2,12 reaches the metal shield 4,14. These signals attempt to be grounded, and in the prior art connectors discussed above, they travel laterally across the length of the metal shields to the ends of the connectors, and these shields have ground leads at their ends. However, as more terminals are added, the length of the connector increases, the shield becomes longer, and the impedance experienced by high frequency signals increases as the signal moves laterally across the length of the metal shield. In prior art applications where the long shield acts like a radial antenna, high frequency signals may jump across the insulating enclosure back to a nearby terminal instead of traveling laterally across the length of the metal shield to ground at its end lead. This can cause high frequency signals to be erroneously transmitted to the wrong circuit terminals.

The present invention advantageously defines a plurality of ground channels by the metallic shield ground leads 9,19 spaced at predetermined intervals along the length of the connector element 1,11. Thus, the ground leads 9, 19 define a section of the ground shield 4, 14 of a predetermined length 1, which is less than the overall length of the connector (Fig. 4), so that any high frequency signal transmitted through the terminals 3, 13 becomes capacitive Coupling to the shield 4, 14, moving over the shortest possible length to the ground circuit, greatly reduces, if not completely cancels, various antenna effects which may transmit high frequency signals to the connector element 1, 11 on the error terminal.

This relationship can be best understood with reference to Figures 6,7. In Fig. 6, it is a schematic diagram of a grounding connector with a length L in the prior art. There are two grounding terminals G at its opposite ends, and the terminal H of the connector carries a high-frequency signal, and the signal is transmitted from the terminal jump to the external ground shield, the signal must travel a distance l ₁ or l ₂ to reach one of the two grounds G. As the overall length L of the connector increases, such lengths may cause antenna effects as described above.

In the present invention, however, the distance to the nearest ground path is considerably reduced, particularly when multiple ground leads are employed at regular intervals. Fig. 7 schematically shows a connector of the present invention with three grounding leads G formed on its grounding shield at equal intervals _l1 . These intervals l ₁ are used as a fractional value to reduce the shortest distance from any high-frequency terminal h of the connector to both ends of the channel to no greater than the length of the connector, and the fractional value is equal to $\frac{1}{N+1}$

where N = the number of ground leads used for any length of the connector. In Figure 7, three ground leads are used, so the shortest distance to any ground path is approximately no more than one quarter of the length L of the connector, i.e., $\left(\frac{1}{3+1}\right)\×L$

It is important that the ground leads 9, 19 of the ground shields 4, 14 will not The coplanarity of the solder tail portions 3C, 13C of the connectors 1, 11 is affected.

The number, position and spacing of the ground leads 9, 19 of the ground shield 4, 14 will be determined in advance depending on which terminal of the connector element 1, 11 the high frequency signal is applied. For example, if a high frequency signal is applied to only one or two terminals, only a single ground lead may be used to contact a select terminal close to the high frequency signal transmission terminal.

Referring now to FIG. 3 , there is shown an electrical connector assembly 23 in which a plug connector element 21 of similar construction to FIG. 1 is engaged to a conventional receptacle connector element 22 . FIG. 4 shows a front view of the plug connector element 21 , and FIG. 5 shows a front view of the socket connector element 22 . In these figures, the same reference numerals as employed in FIG. 1 are used to designate the same components, and descriptions are omitted. The ground terminal 24 of the plug connector element 21 that contacts the ground lead 9 of the metal shield 4 is connected to a ground circuit on an associated circuit board (not shown), and the terminal 25 of the opposite mating socket connector element 22 is also in contact. The ground terminal 24 of the plug connector element 21 is connected to a ground circuit. The contact portion 68 of the ground lead 9 is in contact with the ground terminal 24 of the plug connector element 21, and at the same time, the main portion 69 of the terminal 9 extends in the opposite direction, that is, to the outside of the connector element 21, to contact the ground of the socket connector element 22 shielding 14.

As can be appreciated from the above description, high frequency signals induced in the metal shield are thus allowed to travel over the shortest possible path to the ground circuit, thereby reducing antenna effects and preventing undesired transmission of high frequency signals through the wrong terminals.

It will be appreciated that the present invention has the same applicability to circuit card connectors, wherein the recess of the connector accepts a printed circuit board, such as an edge card, rather than an opposing mating connector element.

It will be appreciated that the embodiments of the invention discussed herein are merely exemplary of few applications of the principles of the invention. Numerous modifications can be made by those skilled in the art without departing from the spirit and scope of the invention.

Claims (8)

1. An electrical connector has an elongated connector outer box made of insulating material, the outer box has a groove extending along the length direction between its inner facing end faces, and the groove of the outer box is formed by the connector A pair of side walls define at least a portion, a plurality of conductive terminals are arranged along facing inner surfaces of the side walls of the connector, a metal ground shield is arranged on the outer surface of the connector, and it is centered with the terminals , characterized by: at least one of said conductive terminals is a ground terminal, and said connector housing includes at least one hole formed in a side wall thereof, the at least one hole being centered with said connector ground terminal, said ground shield having a body part, the body portion has a window-shaped U-shaped opening formed therein, which defines at least one ground lead, the connector housing hole is centered and opposite to the at least one ground lead, and the at least one ground lead has a defined The free end and tail end in the window-shaped U-shaped opening, the tail end of the ground lead and the body part of the ground shield are integrally formed, and the free end of the ground lead passes through the hole in the outer box of the connector extending, and in electrical contact with, the ground terminal of the connector terminals to define a ground path between the ground shield and the ground terminal. 2. The connector defined in claim 1, wherein said ground shield has a plurality of window-like U-shaped openings formed in said body portion, said U-shaped openings defining a plurality of contacts with said ground shield. a ground lead integrally formed on the body portion of the object, and the conductive terminal includes a plurality of ground terminals, the connector housing includes a plurality of holes formed therein, each hole being centered with a single U-shaped opening, the ground lead A plurality of individual ground channels are defined on the connector by extending through the connector housing aperture into electrical contact with the ground terminal. 3. The connector defined in claim 1, wherein said ground shield extends along an outer surface of said connector housing sidewall. 4. The connector defined in claim 1, wherein said ground shield is disposed on an outer surface of one of said connector housing side walls such that said ground shield and some of said connector terminals are located at least one opposite side of the connector housing side wall. 5. The connector defined in claim 2, wherein said ground leads are spaced apart at predetermined intervals along the length of said ground shield. 6. The connector defined in claim 5, wherein said spacing is irregular. 7. The connector defined in claim 1, wherein said connector recess is adapted to receive a mating connector element thereon. 8. The connector defined in claim 2, wherein said ground shield has a predetermined number of ground leads formed thereon which contact some number of said connector ground terminals, wherein any conductive terminal and The distance between the nearest ground paths of the connectors is approximately no greater than: $\frac{1}{N+1}\×L$ where L = length of connector N = number of ground leads

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