The present invention relates generally to high speed connectors, and more particularly to high speed mezzanine, or board-to-board connectors.
The electronics industry keeps improving the speed and efficiency of its devices not only in size but in speed of operation. In addition, increased emphasis is being placed on reducing the cost of components in the electronics industry, including the cost of connectors. In order to facilitate the manufacture of these devices, connectors are required that operate at high speeds. Typical construction of high speed connectors involves the use of individual metal shields that may be mounted along one or both sides of a connector. Signal terminals are usually mounted inside the connector housing and spaced from the shield. This construction involves the forming and mounting of a separate shield, which adds to the cost of the connector. The use of external shields also may increase the size of the connector, thus defeating the aim of reducing the size of the connector. The use of external shields also requires that the two housings overlap and thus increases the overall size of the connector structure. A need therefore exists for a low cost connector having a structure suitable for high speed use and which may be used in board-to-board applications.
The present invention is directed to a high-speed connector that overcomes the aforementioned disadvantages.
Accordingly, it is a general object of the present invention to provide an improved high speed connector for board to board applications.
Another object of the present invention is to provide a board-to-board connector having interengaging plug and receptacle members that are plated with a conductive coating in a manner so as to form a common shield, or ground plane, extending over selected surfaces of the plug and receptacle members, the plug and receptacle members having a plurality of individual compartments, each of which contains a pair of differential signal terminals.
Yet another object of the present invention is to provide an improved connector for use in board-to-board or mezzanine applications wherein exterior surfaces of the connector are plated with a metal plating so as to define a reference ground or grounding shield on the connector without the need for a separately formed grounding shield.
A further object of the present invention is to provide an improved shielded connector for board-to-board applications in which the connector includes first and second parts that mate together to form a single unit, each of the two parts including a housing having a plurality of cavities formed therein, each of the cavities including a dielectric insert, each insert including at least a pair of differential signal terminals adapted for termination to corresponding conductive traces on a circuit board, the connector parts further including interengagement means formed therewith and extending lengthwise thereof.
Still another object of the present invention is to provide a connector of the type previously described wherein the interengaging means includes a plurality of recesses, or cavities, formed in the sidewalls of one of the parts, the recesses being separately of intervening columns, and a plurality of spring fingers, or projections, formed in the sidewalls of the other of the two parts, the spring fingers being received within corresponding recesses of the other part, and the interengaging means being coated with a conductive material so that a ground connection is made and maintained when the two connector parts are engaged together such that the pairs of differential signal terminals held in each cavity are electrically shielded, or enclosed by a reference ground, throughout the height extent of the connector.
Yet another object of the present invention is to provide a board to board connector having male and female connector components that interengage with each other, each of the male and female parts including an insulative housing that holds a plurality of individual terminal assemblies therein in cavities that are defined by corresponding walls of the connector components, the exterior surfaces of the two connector components being plated with a metal so as to provide a unitary grounding datum around each of the connector assemblies along substantially all of the surfaces of the connector components, each of the two connector components including a center engagement member that runs lengthwise through the connector components, one of the center engagement members having a contact blade formed integrally therewith and the other of the center engagement members including a plurality of spring arms, also integrally formed with the connector component so that the grounding shield portions of the two connectors make contact with each other first before the terminals of the connector do.
Still a further object of the present invention is to provide a board to board connector having two connector components that are matable with each other, and wherein the connector components include a plurality of terminal assemblies disposed therein, but electrically isolated from each other by grounding portions applied to exterior surfaces of the connector components, the two connector components being blind matable and being capable being zippered into and out of engagement with each other.
The present invention accomplishes these and other objects by way of its structure. In one principal aspect of the present invention and as exemplified by a first embodiment thereof, the connector assembly of the invention includes a pair of interengaging connector halves. Each connector half is formed as a housing from a dielectric material and has an elongated body portion defined by two opposing walls and two parallel sidewalls. In another principal aspect, a plurality of individual cavities are formed in each of the connector halves, with the connector half sidewalls defining sides of some of the cavities and cross walls defining other portions of the cavities. Each cavity contains a terminal insert that preferably takes the form of a dielectric body with at least a pair of conductive signal terminals therein that are adapted at one end, for mating to a circuit board and at the other end, for mating with corresponding opposing terminals in the other connector half. Each such pair of differential terminals is enclosed within each cavity and when the two connector halves are engaged together the pairs are fully enclosed within their respective cavities. The connector halves are preferably plated with a conductive material on all their exposed surfaces so that the conductive material forms an electrically-conductive shield around each cavity, thereby providing a grounding interface between and around the discrete pairs of wires.
In another important aspect of the invention, each of the connector halves is provided with interengaging means that preferably extend lengthwise along the connector halves. In one embodiment, these interengaging means run lengthwise along the sidewalls of the connector halves so that the engagement occurs along the sides. In another embodiment, these interengaging means extend lengthwise along central walls of the two connector halves so that the engagement occurs along the center of the connector.
The interengagement means preferably utilizes a press fit type of engagement and in one embodiment, takes the form of recesses formed in the connector halves and opposing resilient engagement arms, pairs of which are received within each recess. The arms are slightly larger in spacing than the recesses and are split by an interengaging slot that provides them with a measure of resiliency so that they are slightly compressed when received by corresponding opposing recesses. Both the arms and recesses are conductively plated so that reliable electrical contact is made within the plane of the engagement means to ensure electrical isolation of the differential signal terminals held in the connector cavities from other differential signal pairs.
In still another embodiment of the invention, the interengagement means extends down a general centerline of the two connector halves and includes a contact blade in one half and a plurality of spring arms in the other connector half.
By applying the conductive material to all the connector surfaces near the cavities, including the interengaging recesses and engagement arms, each pair of differential signal terminals is fully encompassed by a shield which will improve its performance and result in a quieter connector from the electrical standpointxe2x80x94electrical xe2x80x9cnoisexe2x80x9d does not enter the cavities and electrical noise will not exit the cavities. The press-fit contact between the engagement arms and the recesses maintains the integrity of the ground connection within the plane of the connector sidewalls.
In another embodiment of the invention, the connector halves are designed so that one is easily inserted into the other in a xe2x80x9czipperingxe2x80x9d fashion, that is, one end of one connector half may be inserted into the other end of the other connector half and the one connector half may be then pivoted or rocked into place and engagement with the other connector half. In this embodiment, the other connector half preferably includes a continuous, outer skirt that is integrally formed therewith and which has a height sufficient to extend up past the mating face of the one connector half so as to provide effective and additional shielding in the mating interface region of the two connector halves.
These and other objects, features and advantages of the present invention will be clearly understood through a consideration of the following detailed description.