Grounding Plate Connector

Connectors with multiple pin contacts may include capacitors for filtering out high frequency noise passing through some of the pin contacts. The connectors may also provide a direct ground connection for a pin contact, and may allow signals to pass through a contact without grounding or capacitive filtering. A number of different arrangements have been proposed, which involve the need for soldering and other relatively difficult operations, and which result in a connector of only moderate reliability and strength which cannot withstand abuse. A connector which could contain numerous pins in a connector of small size, with selected pins being capacitively filtered, grounded, or neither filtered nor grounded, all in an arrangement which enabled relatively low cost and very rugged fabrication and repair, would be of considerable value.

In accordance with one embodiment of the present invention, a connector is provided which is rugged and of relatively simple design. One connector includes a ground plate device and an insulator device lying adjacent to one another and having aligned holes. The insulator device has a metal plated surface extending to a plated hole. A layer of dielectric material lies on one of the devices and a metal overlayer lies over it. The insulator and grounding plate are in facewise contact so that when a pin contact engages the plated hole of the insulator, it is coupled through the capacitor fromed by the dielectric to the grounding plate. The grounding plate can be formed of hard metal and coated with a softer metal that plates one of its holes, so a pin contact can displace some of the softer metal in the hole to make good contact with the grounding plate.

The novel features of the invention are set forth with particularity in the appended claims. The invention will be best understood from the following description when read in conjunction with the accompanying drawings.

FIG. 1 is a front elevation view of a connector constructed in accordance with one embodiment of the present invention.

FIG. 2 is a view taken on the line 2--2 of FIG. 1.

FIG. 3 is a view taken on the line 3--3 of FIG. 1.

FIG. 4 is an enlarged view of a portion of FIG. 3.

FIG. 5 is a view taken on the line 4--4 of FIG. 3 shown with a form of pin contact that can be used.

FIG. 6 is an enlarged view of a portion of FIG. 4.

FIG. 7 is a partial enlarged view of another embodiment of the invention.

FIG. 2 illustrates a connector 10 which includes a group of pin contacts 12 which can carry electricity, such as in the form of signals of low power, between their rearward and forward ends 14, 16. The connector includes a shell device 15 comprising two shell halves or shells 18, 19, surrounding much of the connector, and three insulators 20, 22, and 24 which can serve to hold the contacts in position. This connector includes a metal grounding plate 26 which is electrically grounded and which lies between the shell halves and is securely fastened to them. The electrically grounded plate 26 facilitates the capacitive coupling of some of the contacts to ground, to filter out high frequency noise which may be induced in a contact by external electromagnetic or electrostatic radiation. The grounding plate also permits the direct grounding of a contact where that is desired. The insulators include a forward insulator 20 lying adjacent to a flat forward face 26F of the grounding plate, a rearward insulator 22 lying adjacent to a flat rearward face 26R of the plate, and a backup insulator 24 lying behind the rearward insultor.

The insulators and grounding plate have aligned holes 31-34 through which each contact passes. As shown in FIG. 1, this particular connector has five elongated contacts of which three 41-43 are capacitively coupled to ground through the connector, of which one 44 is directly connected to ground through the connector, and of which one 45 is neither directly nor capacitively coupled to ground. The contacts extend parallel to a lengthwise axis 46 which extends in forward and rearward directions indicated by arrows F and R (FIG. 2).

FIG. 3 shows three of the contacts 44, 42, and 45. As mentioned above, the middle contact 42 is capacitively coupled to ground. The rearward insulator 22 includes a plating layer 50 which is formed by a copper plating 52 lying directly on the insulator and a solder layer 54 over the copper layer. The plating layer 50 includes a portion 50A which covers a region 56 on a face 58 of the insulator. The region 56 surrounds a hole 33 which closely receives one of the contacts 42. The plating layer also includes a portion 50B contiguous with the portion 50A and which plates the hole 33. The pin 42 is in firm contact with the walls of the hole 33 so they are electrically connected.

As also shown in FIG. 4, the grounding plate 26 carries a softer layer 62 and the grounding plate and softer layer may together be referred to as a grounding plate device. A dielectric layer 64 lies over and is bonded to the softer layer, and an overlayer 66 lies over and is bonded to the dielectric layer. The sandwich formed by the overlayer 66, dielectric layer 64 and the softer layer 62 on the grounding plate form a capacitor. Referring again to FIG. 3, the diameter of the capacitor 70 around the contact 42 is limited by a gap 68 in the overlayer around the region 56. The insulator 22 and grounding plate 26 are pressed face-wise towards one another, so that the plating layer 50 on the insulator makes good wide area contact with the overlayer 66 on the grounding plate, at least in the region 56, but they are not bonded to each other. The pin contact 42 is connected through the plating layer portions 50B and 50A to the overlayer 66 in the region 56, so that it is capacitively coupled to the grounding plate 26. As a result, any sharp spikes of voltage induced in the pin contact 42 by either electromagnetic or electrostatic radiation, will be filtered out by the capacitor at 70 formed by the sandwich of the overlayer 66, dielectric 64, and the soft layers 62 on the grounding plate. It is possible to not use the softer layer 62, in which case the dielectric layer can be deposited directly on the grounding plate 26 if the plate is of a conductive material. It may be noted that the overlayer 66 is deposited on the dielectric layer to assure direct contact everywhere with the dielectric layer so the capacitance is predictable and does not vary if the connector is vibrated.

FIG. 3 shows another contact 44 which is grounded by connection at a softer layer portion 71 which plates a hole 72 in the grounding plate. The contact 44 has a portion 74 lying in the hole in interference contact therewith, and displaces some of the softer layer portion 71 on the walls of the hole. FIG. 5 shows the general shape of one form of a pin contact of a type which is disclosed in U.S. Pat. No. 4,296,390. FIG. 6 shows how an edge 76 of the contact displaces part of the soft layer 62 to make good electrical connection with the grounding plate 20. The grounding plate material is harder then the material of the pin contact.

FIG. 3 shows another pin contact 45 which is neither capacitively nor directly connected to ground, so that even high frequency signals can pass through the pin contact 45. In one connector of this type which includes twenty-five contacts, twenty-three are filtered contacts that are capacitively coupled to ground, one is directly grounded, and one is a feed-through contact which may carry power and which is neither capacitively nor directly grounded.

The connector shown in FIG. 2 includes forward and rearward shell halves or shells 18, 19 having ends that are rigidly attached to the peripheral portion 84 of the grounding plate 26 as by welding to form a reinforced housing. The shells surround regions lying beyond the faces of the grounding plate. The grounding plate 26 has a considerable thickness T (FIG. 3) compared to its width W (FIG. 1), so that the grounding plate serves as the main reinforcing member of the connector to provide considerable ruggedness. Also, this can assure flat surfaces or faces on the plate. In one example, the grounding plate has a width W such as 11/2 inches and a thickness T of 50 mil (1 mil equals 0.001 inch) so the plate has a thickness greater than one-fiftieth its width (i.e., over 2% of W). For a grounding plate of structural metals, this thickness-to-width ratio provides considerable strength, so the grounding plate can serve as a major structural component that resists bending and adds ruggedness to the connector. For a five contact connector the plate may have a length such as 4 inches.

In a connector that has been constructed, the grounding plate 26 which had a thickness of 50 mil, was constructed of beryllium-copper, and the softer coating 62 was formed of palladium-silver. The dielectric layer 64 was formed of barium titanate, and the overlayer 66 was formed of palladium silver. The plating layer 50 on the insulator 22 included a solder layer 54 of silver solder and the layer 52 of copper. Each pin contact such as 45 had a pair of shoulders 86, 88 which abutted corresponding shoulders 90, 92 on the forward insulator 20 and backup insulator 24. The capacitor 70 had a capacitance of 1000 microfarads.

FIG. 7 illustrates a portion of another connector with a contact 80 that is to be capacitively coupled to a ground plate 82. An insulator 84 has a plating 86 in a hole 88 and on a surface 90, formed of a copper layer 92 and a solder layer 94. The dielectric layer 96 is formed on the plating 86 and a conductive overlayer 98 is formed on the dielectric layer to form a capacitor 100. The insulator with these layers is pressed against a face 102 of the grounding plate.

Thus, the invention provides a compact and rugged connector which enables capacitive coupling of at least one pin contact to a ground connection. Such capacitive coupling can be achieved by the use of a grounding plate and an adjacent insulator. A softer metal layer can be formed on the insulator. A dielectric layer is formed over the grounding plate or over the metal layer on the insulator and a metal overlayer is formed over the dielectric layer to form a capacitor. An electrical connection is made between a plated hole in the insulator and the grounding plate through the capacitor. A thick grounding plate can be used which forms a major structural member of the connector and to which the shell of the connector is rigidly attached. The grounding plate can include hard metal which is plated with a softer metal so that a pin contact which is to be directly grounded can connect to the plate by displacing some of the softer metal which plates a hole of the grounding plate.

Although particular embodiments of the invention have been described and illustrated herein, it is recognized that modifications and variations may readily occur to those skilled in the art and consequently, it is intended that the claims be interpreted to cover such modifications and equivalents.