Electrical connectors – Electromagnetic or electrostatic shield – Shielding individually surrounding or interposed between...
Reexamination Certificate
2000-03-31
2001-11-13
Sircus, Brian (Department: 2839)
Electrical connectors
Electromagnetic or electrostatic shield
Shielding individually surrounding or interposed between...
Reexamination Certificate
active
06315608
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to high speed connectors, and more particularly to a connector for terminating a cable having multiple distinct signal channels, each channel including at least a pair of differential signal wires and terminals.
Many shielded connectors are known in the art, in which an insulative connector housing is provided to support a plurality of conductive terminals. The housing may have a metal ground shield to provide additional grounding for the connector and for signal isolation. Notwithstanding the presence of the exterior shield, a separate ground pin is often provided in the connector housing. The external metal shield may use either crimping or a butt contact to hold it together. Such a shield structure is not mechanically robust. This type of shield member also uses interlocking members stamped at the ends of the shield member. The use of these members at that location reduces the ability to use the ends of the shield for shielding purposes.
In multiple-channel connectors, the signal terminals of each channel are typically arranged together in side-by-side order along a mating surface of the connector. These signal terminals are not isolated from each other, which may lead to crosstalk occurring between the signal channel wires, thereby hampering the electrical performance of the connector.
Historically, in multiple-channel connectors, the outermost signal terminals have had a particular electrical relationship to the outer metal shield both to the bottom wall and the vertical sidewalls of the shield. These outermost conductive terminals have a greater electrical affinity to the shield than do the innermost conductive terminals because the innermost terminals are spaced relatively far away from the vertical sidewalls of the shield and have no vertical shield wall close to them. Consequently, the innermost terminals display an electrical affinity for each other rather than to the shield, thereby resulting in crosstalk between them which may lead to potentially degrading interference of signal transmission through the terminals, especially in high speed electrical transmission lines. The electrical relationship between the signal terminals and the outer shield of the connector is therefore potentially unbalanced in these known shielded connectors.
The present invention is directed to a shielded, multi-channel connector having a balanced electrical field relationship between its signal terminals and the shield of the connector.
SUMMARY OF THE INVENTION
It is therefore a general object of the present invention to provide a multiple-channel connector in which the electrical field relationship between the signal terminals of the connector and the outer shield is balanced.
Another object of the present invention is to provide a shielded connector having at least two different signal channels that are electrically isolated from each other by a portion of the outer shield of the connector that extends into the connector housing.
Yet another object of the present invention is to provide a connector particularly suitable for use in multi-channel high speed electrical signal transmission applications, wherein a consistent distance between innermost and outermost signal terminals and an external ground shield is maintained so as to provide a substantially uniform capacitance between these signal terminals and the ground shield.
A further object of the present invention is to provide a shielded connector housing at least two pairs of differential signal terminals, in which a metal grounding shield applied to an exterior surface of the connector, the shield encircling the connector housing and extending between the pairs of differential signal terminals to thereby define a central, signal isolation barrier interposed between the differential signal terminals to provide electrical isolation between the two pairs of differential signal terminals.
A still further object of the present invention is to provide a shielded connector as previously mentioned wherein the signal isolation barrier formed by the shield is substantially encased within part of the connector housing to reduce the required distance between associated pairs of signal terminals.
Yet another object of the present invention is to provide an improved shielded, receptacle connector for mating to a plug connector, the connector having an insulative housing with a receptacle portion that supports at least two distinct pairs of differential signal terminals and a metal shield that extends around the exterior of the housing to encircle the receptacle portion of the connector, the shield being bent around the housing and having two free ends that are aligned with each other in an abutting relationship, the shield free ends rising from the exterior of the connector housing and entering the receptacle portion thereof to thereby define an additional, inner shield wall that extends within the receptacle portion, the shield free ends being encased in the housing and forming part of a key for aligning the opposing plug connector with the receptacle connector.
These and other objects are accomplished through the unique and novel structure of the invention. In one principal aspect of the present invention, and as exemplified by one embodiment thereof, a shielded connector is provided for circuit board applications. The connector includes pairs of conductive signal terminals supported widthwise along an interior face of an insulative connector housing. A metal shield is positioned on the exterior of the connector housing to form a hollow shell in which the connector housing and its associated signal terminals sit. This shield includes signal channel isolation means that serve to better electrically isolate the signal channels from each other and reduce interference between the signal channels.
These signal isolation means include a modification of the shield member to form an internal shield member that extends into the receptacle part of the connector in which the signal terminals sit. This internal shield wall is positioned between the two signal channels, preferably along the center line of the connector so that both signal terminals of each signal terminal pair are positioned equidistant from both the bottom wall of the shield member and a sidewall of the shield member that is in proximity to the signal terminals.
In another principal aspect of the present invention, the external shield member is folded or crimped so that it forms at least one inner shield wall that extends into the receptacle of the connector to thereby define at least one pair of internal shield “corners” in the connector. The inner shield wall of the invention may include a single thickness of the shield member or a double thickness thereof. The inner shield walls may abut each other in this extent into the connector receptacle, or they may be interweaved with each other, or they may be separated by a predetermined distance and filled with connector housing material.
In another principal aspect of the present invention, the inner shield wall may be encased in the same material of which the connector housing is made so that the inner wall may be incorporated into a key of the connector housing. This also reduces the distance between the signal channels in that it utilizes an existing key already accommodated by the connector.
In another principal aspect of the present invention, the connector housing may be molded directly within the formed shield member and ends of the inner wall may be formed and positioned to provide support to mold detail tooling inserted into the shield that will define the receptacle of the connector.
These and other objects, features and advantages of the present invention will be clearly understood through consideration of the following detailed description
REFERENCES:
patent: 4353108 (1982-10-01), Chippel
patent: 4571012 (1986-02-01), Bassler et al.
patent: 4678260 (1987-07-01), Gallusser et al.
patent: 4841102 (1989-06-01), Elsner et al.
patent: 4981447 (1991-01-01), Ichitsubo
Brunker David L.
Lopata John E.
Yap Yew Teck
Le Thanh-Tam
Molex Incorporated
Paulius Thomas D.
Sircus Brian
Zeitler Robert J.
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