The present invention generally relates to the electrical interconnection devices, and more particularly to electrical connectors that are at the interface between a first electronic device and a substrate, mating electrical connector, or a circuit board within an electronic system.
Electrical connectors are used in many electronic systems. As miniaturization of the electronic systems becomes more prevalent, the dimensions of the connector itself decrease but the number of signal circuits routed through the connector increases. This results in an increasing number of signals in the limited space of the connector. As the signal circuits are spaced closer and the transmission speed of the signals increases, electromagnetic interference (EMI) and crosstalk become a serious problem. It is desirable that the components of an interconnection path be optimized for signal transmission characteristics; otherwise, the integrity of the system will be impaired or degraded. Such characteristics include low inductance, increased current carrying capacity, suitable roll-off, and reduced ground bounce. Continuous efforts have been made to develop electrical connectors that have as little effect as possible on electronic system performance and integrity.
Inductance is one concern in designing a connector, particularly when that connector is to be used in a signal transmission portion of a high speed electronic system. An example of one such connector is a so called “board-to-board” connector. A board-to-board connector provides the electrical, and often mechanical interface between printed circuit boards (PCB's) in an electronic system. Such connectors often have an elongated housing defining an elongated array of receptacles or slots for receiving a mating edge of the printed circuit board, or a field of pins projecting from the surface of the PCB that are mated to a corresponding field of contact receptacles. In many applications, such connectors are mounted on two or more PCB's commonly referred to as “daughter boards”, which are mounted to a “mother board.”
An inductive effect results from the interconnection of the PCB's which acts to change the characteristic impedance of the circuit and thereby negatively affect the signal transmission capacity of the system. Accordingly, it is desirable to reduce the inductive effects due to the interconnection of the PCB's, and thereby fulfill a need for an interconnection system that reduces inductive effects between the boards being connected. It would also be desirable to increase the current carrying capacity between the PCB's. Examples of such prior art board-to-board connectors may be found in U.S. Pat. Nos. 6,790,048; 6,776,668; 6,733,305; 6,729,890; 6,609,914; 6,599,138; 6,464,515; 6,338,630; 6,312,263; 6,183,315; 6,089,883; 6,220,903; 6,059,610; 6,036,504; 5,921,787; 5,876,219; and 5,873,742, which patents are hereby incorporated herein by reference.
Electrical connectors are often used in environments where they are exposed to dust and dirt, and may even be used in environments where they are subject to splash or immersion in water. It is desirable to seal the connector assembly to protect the terminals from exposure to the external environment. Very often the connector bodies are each formed with a plurality of passages that extend into the connector bodies from a cable end, and into which the cables and their terminals are received. In a sealed connector application, a seal is provided about the cable such that, when installed in the corresponding passage, it serves to seal the passage from the outside environment. The connectors are also sometimes filled with a potting material which will cover the rear entry of the electrical connector so as to protect it from the ingress of contaminants. It is necessary to prevent the entry of contaminants into the interior of the electrical connector, since these contaminants corrode the electrical contact surfaces which often leads to intermittent or unreliable electrical connections. Many types of seals and sealed connector systems are known for keeping contaminants from entering an electrical connector housing. Examples of such prior art sealed connector systems may be found in U.S. Pat. Nos. 6,821,145; 6,767,250; 6,547,584; 6,383,003; 6,132,251; 6,109,945; 6,050,839; 5,823,824; 5,785,544; 5,775,944; 5,595,504; 5,356,304; 4,983,344; 4,961,713; 4,944,688; 4,934,959; 4,895,529; 4,832,615; 4,776,813; 4,772,231; 4,085,993; 4,150,866; and 4,639,061, which patents are hereby incorporated herein by reference.
All of the foregoing connector systems rely upon one or more resilient conductive contacts having a variety of shapes, sizes, and spring characteristics. A commonly used form of resilient conductive contact includes an interconnection end for matting with a corresponding end of a mating contact or PCB, and a termination end for terminating a circuit trace or wire. These ends are often connected by a resilient portion of the contact which provides for the storage of elastic energy. Prior art resilient conductive contacts may be a single metal structure in the form of a spring to provide the required elastic response during service while also serving as a conductive element for electrical connection. Typically, a combination of barrier metal and noble metal platings are applied to the surface of the spring for corrosion prevention and for electrical contact enhancement. It is often the case that these platings are not of sufficient thickness for electrical conduction along only the surface of the spring. Examples of such prior art resilient conductive contacts may be found in U.S. Pat. Nos. 5,653,598; 5,173,055; 5,059,143; 4,906,194; 4,927,369; 4,699,593; and 4,354,729, which patents are hereby incorporated herein by reference.
One problem in the art exists in that a good material for the construction of a spring, such as a high strength steel, is not a very good electrical conductor. On the other hand, a good electrical conductor, such as a copper alloy or precious metal, often does not provide adequate spring properties. There has been a need in the connector arts for a more resilient conductive contact which incorporates the seemingly opposing requirements of good spring properties, temperature resistance, and high conductivity. Therefore, an improved electrical contact for use in an electrical connector is needed which can overcome the drawbacks of conventional electrical contacts. It is desirable that a good electrical contact element possess the following attributes: (a) usable in a wide variety of inter-connection structures; (b) a large elastic compliance range and low contact forces; (c) capable of transmitting high frequency signals and high currents; (d) capable of withstanding high operating temperatures; and (e) exhibiting high durability, i.e. >500K repeated deflections.
The prior art has been devoid of at least one of the foregoing attributes necessary for a universally applicable electrical connector.
The present invention provides a connector system that often includes a first housing having a first header positioned on a mating face. The first header includes at least one conductive pad that is electrically engaged with a conductor such as a wire. A second housing is provided that is mateable with the first housing, and includes a second header positioned on a mating face. The second header includes at least one conductive pad that is electrically engaged with a conductor, such as a wire, and is positioned in confronting relation with the at least one conductive pad of the first header. A contact interposer is located between the first header and the second header. The contact interposer includes at least one contact that extends continuously through the contact interposer so as to have a portion projecting outwardly toward the at least one conductive pad of the first header and another portion projecting outwardly toward the at least one conductive pad of the second header. The contact interposer is movable between (i) a first position in which the portions of the at least one contact are spaced away from the conductive pads, and (ii) a second position in which the portions of the at least one contact electrically engage both of the conductive pads.
These and other features and advantages of the present invention will be more fully disclosed in, or rendered obvious by, the following detailed description of the preferred embodiments of the invention, which are to be considered together with the accompanying drawings wherein like numbers refer to like parts and further wherein:
This description of preferred embodiments is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description of this invention. The drawing figures are not necessarily to scale and certain features of the invention may be shown exaggerated in scale or in somewhat schematic form in the interest of clarity and conciseness. In the description, relative terms such as “horizontal,” “vertical,” “up,” “down,” “top” and “bottom” as well as derivatives thereof (e.g., “horizontally,” “downwardly,” “upwardly,” etc.) should be construed to refer to the orientation as then described or as shown in the drawing figure under discussion. These relative terms are for convenience of description and normally are not intended to require a particular orientation. Terms including “inwardly” versus “outwardly,” “longitudinal” versus “lateral” and the like are to be interpreted relative to one another or relative to an axis of elongation, or an axis or center of rotation, as appropriate. Terms concerning attachments, coupling and the like, such as “connected” and “interconnected,” refer to a relationship wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise. The term “operatively connected” is such an attachment, coupling or connection that allows the pertinent structures to operate as intended by virtue of that relationship. In the claims, means-plus-function clauses, if used, are intended to cover the structures described, suggested, or rendered obvious by the written description or drawings for performing the recited function, including not only structural equivalents but also equivalent structures.
Referring to
Electrical contacts suitable for use in the present invention may comprise a wide variety of shapes and spring-types, as long as they exhibit a large elastic range and low characteristic impedance. For example, in one embodiment a plurality of c-shaped electrical contacts 2a may be used in connection with the present invention that are made from a sheet of INCONEL X, a corrosion resistant alloy of nickel chromium that is commercially available from Huntington alloys, a division of Inco Alloys International of Huntington, W.Va. 25720. INCONEL X is a trademark of Inco Alloys International. Referring to
In another embodiment, electrical contact 2b is preferably stamped from sheet metal to form a generally planar contact body having first and second major faces 17, 18 corresponding to surfaces of the metal from which it is stamped, often with a thickness T of approximately 0.0045 inches or less. Electrical contact 2b includes a pair of spring arms 20, 21 which are connected at one end by a resilient bight portion 23. Bight portion 23 is preferably an arcuate section which enhances flexibility in the plane of the contact, although bight portion 23 may be defined more sharply by an intersection of arms 20, 21 at an acute angle. Often, bight portion 23 is bisected by central axis A of the contact. Arms 20, 21 are spaced apart at some dimension when the contact is in an undeflected state. Preferably, arms 20, 21 angularly diverge as they extend from bight portion 23, although the arms may be parallel to each other. Arms 20,21 also extend slightly out of the plane of electrical contact body 2b as they extend away from bight portion 23. Arms 20,21 have respective free ends with outwardly facing edges defining a pair of oppositely facing contact noses 25, 26 each engagable with a contact pad disposed on termination header 7, as will hereinafter be disclosed in further detail. Respective shorting sections 29, 30 extend from each of the free ends generally toward each other. Shorting sections 29, 30 are offset slightly from each other due to the arms extending slightly out of the plane of electrical contact 2b. An extremely short electrical path, e.g., as is formed between shorting sections 29, 30, is desirable for high speed (high frequency) devices in order to avoid inductance effects.
Electrical contacts 2a and 2b are often made of a spring temper alloy in which a substantial portion includes precious metals, such as palladium, gold, or silver, as well as nickel and other non-precious metals. Significantly, in addition to spring characteristics, the ability of the contact to mate with a solder lead without transfer of solder metal from the solder lead to the contact is vital. Of the non-noble metals, beryllium-nickel alloy appears to meet that requirement, as do the above-listed precious metals. Since these materials are quite expensive, efficient material utilization is an important factor in deciding on the shape of the electrical contacts 2a and 2b.
Referring to FIGS. 1 and 17–19, electrical contacts such as the foregoing exemplary contacts 2a or 2b may be associated with a wide variety of electrical interconnection systems formed in accordance with the present invention with good effect. For example, electrical contacts 2a or 2b may be positioned and supported within a wire-to-wire interconnection device 100 that includes a pair of substantially circular mateable dielectric housings 60 and 61 that are each molded from a suitable polymer material. Polymeric materials useful in this invention include any material useful in the electronics industry, including, without limitation, thermoplastics (crystalline or non-crystalline, cross-linked or non-cross-linked), thermosetting resins or blends or composites thereof. Illustrative examples of useful thermoplastic polymers include, without limitation, polyolefins, such as polyethylene or polypropylene, copolymers (including terpolymers, etc.) of olefins such as ethylene and propylene, with each other and with other monomers such as vinyl esters, acids or esters of unsaturated organic acids or mixtures thereof, halogenated vinyl or vinylidene polymers such as polyvinyl chloride, polyvinylidene chloride, polyvinyl fluoride, polyvinylidene fluoride and copolymers of these monomers with each other or with other unsaturated monomers, polyesters, such as poly(hexamethylene adipate or sebacate), poly(ethylene terephthalate) and poly(tetramethylene terephthalate), polyamides such as Nylon-6, Nylon-6,6, Nylon-6,10, Versamids, polystyrene, polyacrylonitrile, thermoplastic silicone resins, thermoplastic polyethers, thermoplastic modified cellulose, polysulphones and the like. Examples of some thermosetting resins useful herein include, without limitation, epoxy resins, such as resins made from epichlorohydrin and bisphenol A or epichlorohydrin and aliphatic polyols, such as glycerol, and which can be conventionally cured using amine or amide curing agents. Other examples include phenolic resins obtained by condensing a phenol with an aldehyde, e.g., phenol-formaldehyde resin.
Housing 60 often includes a conductor or wire-receiving passageway 64 extending through a base wall 66 and surrounded by an annular wall 67 that together define an interior recess 69 into which wire-receiving passageway 64 opens (
A pair of guide-cradles 80,81 are often located within housings 60,61 on the interior surface of base walls 66,72, respectively. Guide-cradle 80 often includes a wire-receiving passageway 84 extending through a mating face and surrounded by an annular wall that together define an interior recess into which wire-receiving passageway 84 opens. Guide-cradle 81 includes a wire-receiving passageway 91 extending through a mating face and surrounded by an annular wall that together define an interior recess into which wire-receiving passageway 91 opens. Guide-cradles 80, 81 provide support and organization for wires 99 entering housings 60,61. It will be understood that a wire-crimp contact terminal 101 may also be received within passageways 84,91 so as to form an electrical or signal transmission pathway.
Interposer assembly 3 includes a contact interposer 5 or 5a, a pair of termination headers 7, and one or more pilot pins 9. Interposer assembly 3 is positioned between housings 60,61 with some portions located within housing 60 and other portions located on housing 61 (
In one embodiment that is associated with electrical contact 2a, preformed flat rectangular blanks (not shown) are inserted into openings 104 that have been formed in contact interposer 5 so that ribs 8 are forced into wedging engagement with the sides of contact interposer 5 that define an opening 10 (FIGS. 2 and 4–6). This arrangement holds all of the blanks captive in contact interposer 5 until they are formed into the final c-shape. This forming is done with a pair of forming dies in the usual manner which is typically a two step process. In a first step the outer portions of each end of the blanks are slightly bent in the desired direction of the C-shaped curve. In a second step a final forming to the desired shape is accomplished with a forming die designed for the purpose. Such forming dies are well known in the metal forming art and therefore are not described here.
In another embodiment that is associated with electrical contact 2b, contact interposer 5a includes a plurality of contact cavities 92 arranged in a predetermined pattern or array through its thickness (
Termination header 7 may be formed from a standard expoxy and fiber glass printed wiring board (PCB) material having a plurality of through-bores 112 defined through its thickness and arranged in a regular pattern or array that is complementary to the pattern of through-bores 104 in contact interposer 5 (
Interposer assembly 3 is mounted within a wire-to-wire connector 100 in the following manner. Guide-cradles 80, 81 are first positioned within housing 60, 61, respectively, such that wire-receiving passageways 84 of guide-cradle 80 are arranged in coaxially aligned relation with wire-receiving passageway 64 of housing 60, and wire-receiving passageways 91 of guide-cradle 81 are arranged in coaxially aligned relation with wire-receiving passageway 70 of housing 61. Once in this position, a termination header 7 is positioned on each mating face of each guide-cradle 80, 81. In this position, terminal pads 118 face outwardly. Pilot pins 9 are then fixedly positioned within pilot holes 114 of at least one of termination headers 7 (shown within housing 61 in
In another embodiment, electrical contacts 2b are positioned within cavities 92 of contact interposer 5a with first major face 17 of shorting section 29 being substantially coplanar with the second major face 18 of the shorting section 30 (
Referring once more to
With wires 99 or wire-crimp terminal contact 101 electrically engaged with termination headers 7, within housings 60, 61, housing 60 may be mated to housing 61 so as to complete wire-to-wire connector 100. Referring to the exemplary sequence illustrated in
Of course a wide variety of other connector systems may employ interposer assembly 3 so as to operate in accordance with the present invention. For example, a board-to-board connector system 200 may be formed having a interposer assembly 3 as follows. Referring to
Interposer assembly 3 includes a contact interposer 5 or 5a, a pair of termination headers 217, and one or more pilot pins 9, and is positioned between housings 202,203 with some portions located on housing 202 and other portions located on housing 203 and termination headers 217 (
Interposer assembly 3 is mounted within a board-to-board connector system 200 in much the same manner as with wire-to-wire connector system 100. More particularly, termination headers 217 are positioned such that a peripheral edge surface of each face 222 engages a respective annular ledge 212,214 of housings 202,203. In this position, terminal pads 219 face outwardly toward corresponding pads 225 on printed wiring board 228 (
Housing 202 may be mated to housing 203 so as to complete board-to-board connector system 200 in the following manner. Referring to the exemplary sequence illustrated in
In another example, a wire-to-ribbon cable connector system 300 may be formed having a interposer assembly 3 as follows. Referring to
Interposer assembly 3 includes a contact interposer 5 or 5a, a termination header 317, one or more pilot pins 9, and is positioned between housings 302,303 with some portions located on housing 302 and other portions located on housing 303. In this embodiment, a guide-cradle 80 is disposed in housing 302 and a guide-cradle 81 is disposed in housing 303, which guide-cradles operate as disclosed hereinabove. Termination header 317 is formed from a standard epoxy and fiber glass printed wiring board (PCB) material having a plurality of interconnects 322 (which may often be a combination of plated-through-hole and circuit trace) arranged through its thickness. One or more pilot holes 324 are defined through portions of termination header 317 in locations that will allow for coaxial alignment with pilot holes 106 when interposer assembly 3 is positioned on housings 302 and 303. In this embodiment, interconnects 322 may be plated-through-holes or solid conductive structures, e.g., tin, gold, or the like, and closed off at both ends so as to form a pair of terminal pads 318, 319 on faces 326, 327 of terminal header 317 so as to provide an electrically conductive pathway to corresponding wires 99 and ribbon cable 333 within base walls 306,307, respectively. Terminal pads 318 are arranged on face 326 of terminal header 317 in a regular pattern or array that is complementary to the pattern of electrical contacts 2a or 2b in contact interposer 5 or 5a. An o-ring 119 or equivalent may be fixedly positioned adjacent to face 326 of a terminal header 317 so as to be in surrounding relation to the array of terminal pads 318.
Interposer assembly 3 is mounted within a wire-to-ribbon connector system 300 in much the same manner as with wire-to-wire connector system 100 and board-to-board connector system 200. More particularly, termination headers 317 are positioned on base wall 306 of housing 302. A pair of guide-cradles 80,81 are often located within housings 302,303 on the interior surface of base walls 306,307, respectively, and as previously described hereinabove. Pilot pins 9 are then fixedly positioned within pilot holes 324 of termination header 317 (shown within housing 302 in
Housing 302 may be mated to housing 303 so as to complete wire-to-ribbon connector system 300. Referring to
It is to be understood that the present invention is by no means limited only to the particular constructions herein disclosed and shown in the drawings, but also comprises any modifications or equivalents within the scope of the claims.
This application claims the benefit of U.S. Provisional Patent Application No. 60/586,777, filed on Jul. 9, 2004.
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4529257 | Goodman et al. | Jul 1985 | A |
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Number | Date | Country | |
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20060009055 A1 | Jan 2006 | US |
Number | Date | Country | |
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60586777 | Jul 2004 | US |