Patent Grant
7404718
This present invention relates generally to electrical connectors, and particularly to improving the performance, construction and ease of use of high frequency electrical connectors.
The use of electronic products of all kinds has increased dramatically throughout society, which has led to a significant increase in the demand for improved components utilized within such products. One facet in the utilization of such electronic products involves the coupling of high frequency signals, e.g., data and/or communications signals, between various signal-bearing components, such as electronic circuit boards.
Some electronic products include a rack or frame into which multiple circuit packs are inserted. Generally, a frame includes a circuit board referred to as a “backplane”, while a circuit pack may include one or more circuit boards. A backplane generally includes multiple connectors soldered to and interconnected by conductive traces. A backplane typically provides little functionality other than electrically interconnecting the circuit boards within the circuit packs. A backplane however may also provide electrical connections external to the frame. When a backplane includes functionality, it may be referred to as a “motherboard”. Such is the case, for example, in a personal computer (PC).
Since back planes are sometimes referred to as motherboards, the circuit packs containing circuit boards that are electrically interconnected using such a motherboard backplane are often referred to as daughter cards. Each daughter card includes one or more circuit boards having electrically conductive traces to electrically interconnect various electrical components in a circuit. Electrical components, such as integrated circuits (ICs), transistors, diodes, capacitors, inductors, resistors, etc., may be packaged with metallic leads that are soldered to conductive traces on a daughter card. A daughter card will typically include a connector, proximate an edge, and soldered to the traces, for electrically coupling to a corresponding connector on the motherboard backplane when inserted into the frame.
One common method of attaching electrical components to a circuit board is to include “through holes”, e.g., holes drilled through the circuit board, and land areas in the traces proximate the holes. Wire leads on the electrical components may then be bent or “formed” or configured for insertion through the holes, and soldered to the land areas once inserted, or “placed.”
Readily available through hole male and female connectors, such as GbXJ, VHDM-HSDJ, VHDM7, Hardmetric (HM), CompactPCI, etc. from manufacturers such as Amphenol, Teradyne, Tyco, etc. are often used for interconnecting two circuit boards. Such connectors are available in various sizes, having various arrays of conductive contact pins. Such arrays of pins are generally held together using a dielectric material, forming the connector. Each pin includes a portion extending from the dielectric material that may be inserted into a through hole in a circuit board. A circuit board for use with a respective connector will have through holes corresponding to the pins of the connector. Conductive traces on the circuit board extend from the land areas corresponding to the pins forming nodes in a circuit.
In production, a circuit board is often placed on a conveyer. As the conveyer moves the board, a solder paste is applied to the board. Through hole electronic components, including connectors, are typically hand placed in the corresponding through holes, the solder paste having been applied. The conveyer then carries the board and connector through an oven that heats the solder paste, soldering the connector to the board. Such a process is generally referred to as “wave soldering”.
Another common method of attaching electrical components to a circuit board is referred to as “surface mounting.” In surface mounting, land areas are also included in the traces, but holes through the circuit board are not necessary. In the case of a surface mount connector, rather than each pin including a portion that may be inserted into a through hole in a circuit board, each pin will include an electrically conductive “foot”. A surface mount connector with conductive feet may be slid over and/or bolted to the edge of a circuit board, the feet corresponding to land areas in the traces on the circuit board. Likewise, in production, surface mount connectors may also be wave soldered.
Irrespective of whether one of these connectors is a through hole or surface mount type, each type suffers from common problems once attached to a circuit board. For example, the pins typically found in these connectors are quite fine, or small. Any deviation in alignment when plugging one connector into another can result in the bending of one or more of these pins. This generally causes either a failure of the product under production test, or worse, a failure of the product in the possession of a user or consumer.
When a pin of a connector is bent, the connector must be removed from the board and a new connector installed. This is can be a time-consuming and difficult process. In the case of a surface mount connector, each of the conductive feet must heated one at a time and bent away from its respective land area to remove the connector. Alternatively, all of the conductive feet must be heated simultaneously to re-flow the solder, allowing the connector to be removed from the board. Typically, a hot air gun is used for such heating. This subjects the board, as well other components adjacent to the connector, to a substantial amount of heat. A heat gun in the hands of an inexperienced repair technician can result in the board being ruined, or the adjacent components being damaged. Even when a heat gun is not used, replacement of a surface mount connector can take a considerable amount of time, and still requires a skilled technician.
In the case of a through hole connector, a heat gun also generally must be used. Through hole connectors typically require even more heat to be applied to a board for removal than surface mount connectors. Again, this makes removal difficult, increasing the chances for an unskilled technician to damage the board or surrounding components. In some cases, with connectors having a large array of pins, it becomes impractical, if not impossible, to simultaneously re-flow the solder on every pin. In such cases, the board must be scrapped.
Another problem inherent in prior art connectors is that the geometric arrangement and/or spacing between pins is not maintained through the connector to the surface of a respective circuit board. For example, pins in such connectors are generally used in pairs, a pair of pins carrying either a single ended or differential data and/or communications signal. Deviation in the geometric arrangement and/or spacing of between pins when used as a pair generally results in impedance variation with a change in frequency, thereby degrading the electrical performance of the connector and/or limiting the usable frequency range of the connector. Further, since these pins are arranged in an array, and pairs of pins are generally in close proximity to other pairs of pins, there can be, and often is electromagnetic interaction between pairs and/or pins. Such interaction is typically referred to as “crosstalk”. Ideally, these pins would be consistently spaced throughout, and the connectors would provide some sort of shielding of the pairs to prevent crosstalk. Such connectors provide no shielding, nor is consistent spacing possible. Therefore, there is a need in the prior art to improve upon the connectivity between circuit board and respective motherboards. There is specifically a need to address the problems with such connectors when used with boards handling high-speed data and other communications signals.
One type of connectors used for electrically coupling an electrical component to a circuit board is an elastomeric connector. Generally, an elastomeric connector comprises a body constructed of an elastic polymer material having opposing first and second faces and a plurality of fine conductors that are passed from the first to the second faces. An elastomeric connector may be positioned between land areas on a circuit board and conductive leads on the component, aligning the leads with the land areas. Pressure is then applied to the connector to compress the elastic polymer, providing electrical connection from the land areas on a circuit board on one face through the conductors to leads of the component on the other face. One example of the use of such an elastomeric connector is in electrically coupling a liquid crystal display (LCD) screen to a circuit board in a calculator. However, signals between an LCD screen and a circuit board are low frequency digital signals not high frequency data/communications signals. Therefore, there is little concern for the geometric arrangement of the components or shielding. Thus, elastomeric connectors are essentially often just parallel data and/or power lines.
There have been other uses of elastomeric materials, such as in test fixtures to electrically contact integrated circuit chips in production testing, to couple a ribbon cable to a circuit board, or in coupling a pin grid array to a circuit board. However, again the elastomeric connectors when so used are generally parallel data and/or power lines. Yet another use of an elastomeric material has been in the form of a seal in a connector to thereby extend the shielding provided by an outer conductor in a data cable. Therefore, elastomeric connectors, to date, are essentially for power transfer or simple low frequency digital signal transfer or shielding. Therefore, such connectors have not been particularly suited to the transfer of high frequency signals, e.g., data and/or communications signals in a connector assembly between two circuit boards.
It is desirable to address drawbacks in the prior art in providing high frequency data and/or communications connections between electrical circuit boards.
Furthermore, it is desirable to maintain the geometric arrangement and alignment of conductors in a connector.
Additionally, it is desirable to improve the replacement and serviceability of a high-speed data connector assembly.
It is further desirable to provide multiple such connections in a compact arrangement, such as an array, that are shielded.
These objectives and other objectives will become more readily apparent from the summary of invention and detailed description of embodiments of the invention set forth herein below.
The present invention addresses the above drawbacks and provides the benefits of an elastomeric connector, while providing high frequency data and/or communications connections between two electrical circuit boards or other components. To this end, and in accordance with principles of the present invention, a connector assembly includes a signal array including at least one shielded conductor having at least one central or inner conductive core or element and a conductive outer structure or element coupled with a body. A compressible interface element with two faces and a plurality of conductive elements extending from face to face is coupled between the arrays and another signal-bearing component, such as another similar array or a circuit board. The compressible interface element is compressed between the array and signal-bearing component to pass a high-speed data and/or communication signal from the array to the signal-bearing component.
The connector assembly of the invention maintains the geometric arrangement of the inner and outer conductive elements of the array cables through the connector. The connector assembly is also easily replaced requiring no soldering and is, therefore, easily and readily serviceable.
In one embodiment of the invention, a signal array and two elastomeric connectors are placed between two substantially parallel circuit boards to electrically pass high frequency data and/or communications signals between the circuit boards.
In another embodiment of the invention, a signal array and two elastomeric connectors are placed between two substantially orthogonal circuit boards.
In another embodiment of the present invention, a signal array comprises at least one coaxial conductor including a central conductive core and a conductive outer structure.
In yet another embodiment of the present invention, a signal array comprises at least one twinaxial conductor including two central conductive cores and a conductive outer structure.
In another embodiment an array of cables terminate in a connector body at a face surface. The connector interfaces with another connector similarly constructed through a compressible interface element.
In still another embodiment, the array and connector body interface with a circuit board through a compressible interface element.
These features and other features of the invention will be come more readily apparent from the Detailed Description and drawings of the application.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with a general description of the invention given below, serve to explain the principles of the invention.
Referring to
Although not shown for ease of illustration, those of skill in the art will appreciate that central conductive core areas 28 and conductive outer structure areas 30 extend to traces on multiple layers of circuit boards 12, 14, and, in some instances, to electrical components, e.g., integrated circuits (ICs), transistors, diodes, capacitors, inductors, resistors, etc., soldered to those traces. Such traces, in part, form nodes in circuits on circuit boards 12, 14. The construction of and uses for circuit boards including traces on multiple layers are well known to those of skill in the art.
For example, signal-bearing components or circuit boards 12, 14 may be a backplane and a circuit pack. Circuit boards 12, 14 may be two circuit boards comprising a circuit pack. Circuit boards 12, 14 may also be a motherboard and a daughter card. Other applications wherein two substantially parallel circuit boards are desired will readily appear to those of skill in the art.
Again, a signal array, such as signal array 16, comprises one or more blocks or wafers 32, each including one or more shielded conductors 18. Each shielded conductor 18 includes an axial conductive element 38 and an outer conductive element 40 surrounding the axial conductive element 38, as may be seen in
Shielded conductors are generally used for high-speed or high frequency signals, such as high-speed data and/or communications signals. Signals as defined herein mean essentially conducted voltages and/or currents associated with conductors and not necessarily “smart” signals. Further, the simultaneous conduction of voltages and/or currents create a data signal or other signal.
Desirable attributes of shielded conductors worthy of particular note are minimizing interference and constant impedance. For example, the outer conductive element or shield of a shielded conductor is generally connected to a voltage reference or electrically grounded. Thus, other shielded conductors likewise having grounded shields will generally be resistant to interference by the signals carried by the adjacent shielded conductors. Such coupling or interfering of signals between proximate conductors may also be referred to as “crosstalk”. The lack of “crosstalk” between shielded conductors is generally due to there being no voltage gradient between the various shields due to each of the shields being grounded or connected to the same or similar reference or voltage potential.
Further, shielded conductors are commonly available in two types, though others may be possible. One type is coaxial, or coax, and another type twinaxial, or twinax. Coaxial conductors generally have a central or inner conductive core or center conductor equally spaced or centered axially within a shield or outer conductive structure. An outer conductive structure may be braided wires or a conductive foil, or some combination thereof, or some rigid or semi-rigid adequately conductive metal.
Similarly, twin axial conductors generally have two central conductive cores or center conductors spaced apart or twisted and equally spaced or centered axially, within a shield or outer conductive structure. Thus, both types have an axial conductive element and an outer conductive structure surrounding the axial conductive element, an axial conductive element being defined herein as a conductive element located or spaced axially within an outer conductive element.
In use, the center or inner conductor of a coaxial conductor generally carries a signal that varies with respect to the shield, which is generally electrically grounded as mentioned above. Such a signal may be referred to “single-ended,” in that only the center conductor carries a signal that varies with respect to ground. In contrast, a twinaxial conductor has two center conductors that carry signals that are the same, but 180 degrees out of phase. The advantage in a twinaxial conductor is that any interference that is induced or coupled into the center conductors of the twinaxial conductor past the shield may be cancelled when the two out of phase signals are added together. Thus, the signal is formed by the difference between the two out of phase signals carried by the center conductors, such a signal being referred to “differential.”
If the signals carried by the signal array are low speed or low frequency, the spacing between the center conductors and the shield of the array elements is of little consequence as is the way in which the array is coupled to another signal-bearing component. However, as the speed or frequency of the signals carried by center conductors is increased, the spacing between the center conductors and the shield becomes significant and any misalignments or other problems in the way in which the signal array couples with another signal-bearing components causes signal degradation and possible signal errors, particularly in high frequency data signals. For example, with high-speed data and/or communications signals, the spacing between the center conductors and the shield, along with the center conductors and the shield themselves, form a capacitor of significant value. Such capacitance in a shielded conductor is often referred as a “distributed capacitance,” as the capacitance is distributed along the length of the conductor, and may be described in units of picofarads per foot (pF/ft).
Moreover, the overall size or dimensions of a shielded conductor, along with the spacing, determines a characteristic impedance for the conductor at particular frequency ranges of use. For example, common impedances for coaxial and twinaxial cables are 50, 75, 100, and 110 ohms. Such characteristic impedances are of particular importance in designing a high frequency circuit for maximum power transfer between a source and a load.
The present invention addresses both interference and constant impedance, as well as other things, in providing connectors and/or connector assemblies for use with high-speed data and/or communications signals and related signal-bearing components.
For example, and as shown in
Referring now to
Compressible interface elements 20, 22 are used between the array 16 and other signal-bearing components and each include two faces 33, 34 and conductive elements 36 (not shown in
Elastomeric connectors may be constructed using extremely accurate silicon rubber with anisotropic conductive properties. Such connectors may include anywhere from 300 to 2,000 fine metal wires per square centimeter embedded in the thickness direction of a transparent silicone rubber sheet. Such fine metal wires are generally gold-plated to ensure low resistivity and the ability to withstand relatively high current flow.
In use, compressible interface elements 20, 22 are placed between corresponding shielded land areas 24, 26 on circuit boards 12, 14 and shielded conductors 18 in signal array 16, aligning the central conductive core areas 28 and the conductive outer structure areas 30 with the axial or conductive element 38 and the outer conductive element 40 of the shielded conductors or cables 18, respectively. Guide pins or posts 21 also molded into LCP material 19, corresponding to holes 23 in circuit boards 12, 14 and holes 25 in compressible interface elements 20, 22 are configured to aid in, or provide, such alignment. Those of ordinary skill in the art will appreciate that other structures such as notches, raise portions or bumps and corresponding recessed portions, etc. may be used in the alternative to aid in or provide alignment.
Pressure is then applied to compressible interface elements 20, 22 to compress the elements 20, 22 such that the conductive elements 36 provide electrical connection from shielded land areas 24, 26 on circuit boards 12, 14 on faces 32 through elements 36 to shielded conductor 18 on faces 34. In that way, signals are passed between the signal array and the signal-bearing component while maintaining geometric arrangement of the inner and outer conductive elements of cables 18 of array 16 and conductive elements of the signal-bearing component, such as a circuit board. Such pressure or compression typically causes those conductive elements making such contacts to distort or bend as shown, whereas those conductive elements that do not make such contacts generally remain straight.
It will be appreciated that holes 25 in compressible interface elements 20, 22 are not necessary for alignment of compressible interface elements 20, 22. To function adequately, compressible interface elements 20, 22 only need cover shielded land areas 24, 26 and the ends of shielded conductors 18, as aligned. Which conductive elements 36 within compressible interface elements 20, 22 make contact with or electrically couple the shielded land areas 24, 26 and the ends of shielded conductors 18 is irrelevant. Rather, holes 25 in compressible interface elements 20, 22 merely serve to hold compressible interface elements 20, 22 in place as connector assembly 10 is assembled.
However, proper alignment of corresponding shielded land areas 24, 26 on circuit boards 12, 14 and shielded conductors 18 in signal array 16, is necessary to electrically couple the circuit boards. Moreover, and with respect to each shielded conductor 18, the compressible interface elements 20, 22, when compressed between the signal array 16 and a signal bearing component, such as circuit boards 12, 14, maintains the geometric arrangement of the axial conductive element 38 and the outer conductive element 40 through the compressible interface elements 20, 22 to the signal bearing component, or circuit boards 12, 14. Further, those conductive elements 36 under pressure and contacting the central conductive core areas 28 and the conductive outer structure areas 30 with the axial conductive element 38 and the outer conductive element 40, respectively, form, in effect, a solid center conductor and a solid surrounding outer shield due to the density of the conductive elements 36 in compressible interface elements 20, 22. That is, there is effectively a 360° shield formed around the center conductor of each cable. Still further, when compressible interface elements 20, 22 are compressed, the shielding of each shielded conductor 18 is extended, and in effect, the compressible interface connectors take on the shielding arrangement of the shielded conductors 18 in blocks 32a-d.
Pressure may be applied using a variety of fasteners. For example, and as shown in
Referring now to
Each block 32a-d may be constructed by molding, potting or otherwise embedding shielded conductors or cables 18, such as, for example, lengths of semi-rigid coax, in a non-conductive substance, such as a LCP material 19, as mentioned above. The contact faces or face surfaces 48 of the blocks 32a-d may then be machined or polished to improve the co-planarity of the shielded conductors 18 or semi-rigid coax on a contact faces or face surfaces 48. Such machining or polishing improves the interface between signal array 16 and compressible interface elements 20, 22. The inner conductive elements 38 and outer conductive elements 40 of the cables 18 are presented at the face surfaces 48. Guide pins or posts 21 may likewise be molded into one or more blocks 38a-d. For example, and as shown in
The array 16 of shielded conductors 18 in combination with compressible interface elements 20, 22 that extends the shielding of the shielded conductors 18 may be used for single-ended signals, such as high-speed data and/or communications signals in one aspect of the invention. Shielding is particularly useful in preventing interference when using such high-speed signals. Moreover, shielding prevents “crosstalk” between shielded conductors placed in close proximity with one another, and facilitates the construction of dense or tightly spaced arrays of shielded conductors. The present invention provides a connection between a signal array and another signal-bearing component and maintains the desired signal integrity at the connection.
In addition, connector assembly 10 includes elastometic connector elements, e.g., compressible interface elements 20, 22, in providing high frequency data and/or communications connections between circuit boards 12 and 14. In doing so, connector assembly 10 requires no soldering. Further, no soldering or special skill is required repair the connection, such as to remove and replace one of the compressible interface element 20, 22 or the signal array 16. A user need only remove the fasteners 42, 46, reposition new compressible interface elements, and/or a new signal array, and, with the aid of guide posts 21, reinstall the fasteners 42,44. Moreover, connector assembly 10 includes no pins that may be bent or broken in assembly, resulting in degradation of the signal or failure of the connection.
Furthermore, connector assembly 10 extends the geometric arrangement of the shielded conductors 18 in the signal array 16 through the connector assembly 10 to the surface of the signal-bearing component, such as circuit boards 12, 14. By extending the geometric arrangement, with its inherent shielding, through the connector assembly, the signal integrity is maintained, crosstalk between shielded conductors in the array is reduced, while the variation in impedance with changes in frequency of each respective shielded conductor 18 is also reduced. Thus, connector assembly 10 improves the replacement and serviceability of high-speed data and/or communications connections and interfaces.
The invention is also useful in a twinaxial arrangement, having two inner conductive elements. Referring now to
Although not shown, those of skill in the art will appreciate that central conductive core areas 88 and conductive outer structure areas 90 extend to traces on multiple layers of circuit boards 72, 74. Such traces form nodes in circuits on circuit boards 72, 74, the construction of and uses for circuit boards including traces on multiple layers being well known to those of skill in the art. For example, circuit boards 72, 74 may be a backplane and a circuit pack, two circuit boards comprising a circuit pack, or a motherboard and a daughter card. Other applications of two such circuit boards will readily appear to those of skill in the art.
Signal array 76, comprises four (or more or less) wafers 92a-d, each containing four (or more or less) shielded conductors 78. Each shielded conductor 78 includes two axial or inner conductive elements 94 and a conductive outer element 96, as may be seen in
Referring now to
Compressible interface elements 80, 82 each include two faces 98, 100 and conductive elements 102 that extend from face 98 to face 100, and are constructed of an elastomeric material. Thus, compressible interface elements 80, 82 may be referred to as elastomeric connectors and may be similar to those previously described above as elements 20, 22.
Compressible interface elements 80, 82 are placed between corresponding shielded land areas 84, 86 on circuit boards 72, 74 and shielded conductors 86 in signal array 76, aligning the central conductive core areas 88 and the conductive outer structure areas 90 with the two axial conductive elements 94 and the conductive outer element 96, respectively. For example,
Pressure is applied to compressible interface elements 80, 82 such that conductive elements 102 provide electrical connections from shielded land areas 84, 86 on circuit boards 72, 74 on faces 98 through elements 102 to shielded conductors 78 on faces 100. Such pressure causes those conductive elements making such contacts to distort or bend slightly as illustrated. Pressure may be applied using bolts 104 extending through corresponding holes 106 in circuit boards 72, 74 with nuts 108, as shown. Such bolts 104 may also aid in alignment in some embodiments. Other fasteners may be used in the alternative without departing from the spirit of the present invention.
When compressible interface elements 80, 82 are compressed as illustrated, conductive elements 102 contacting conductive outer element 96 and conductive outer structure areas 90 form generally a 360° shield around, or “shield”, those conductive elements 102 contacting axial conductive elements 94 and central conductive core areas 88. Thus, under pressure, conductive elements 102 of compressible interface elements 80, 82 “extend” the geometric arrangement or shielding of shielded conductors 78 through to land areas 84, 86, or the surface, of circuit boards 72, 74.
Referring now to
Each wafer 92a-d may be constructed using circuit board materials well know to those of skill in the art, such as fiberglass, epoxy, Teflon, etc. Coupled to each wafer 92a-d are mounting ends 110. Mounting ends 110 may be constructed of a non-conductive substance, such as a LCP, and molded or formed to receive shielded conductors 78. Shielded conductors 78 may be lengths of semi-rigid twinax cables well known to those of ordinary skill in the art. The contact faces or face surfaces 112 of mounting ends 110 and shielded conductors 78 may be machined or polished to improve the co-planarity of the shielded 78 on the contact faces 112. Such machining improves the interface between signal array 76 and compressible interface elements 80, 82. The inner 94 and outer 96 conductive elements of the conductors 78 are presented at the face surface in a generally co-planar arrangement for presenting the signal array to a signal-bearing component such as the circuit boards 72, 74. Unlike array 16, the conductors 78 are not completely embedded in molded material such as LCP.
Shielded conductors 78 accompanied by compressible interface elements 80, 82 that extend the shielding of the shielded conductors may be used for differential signals, such high-speed data and/or communications signals. Shielding is particularly useful in preventing interference when using such high-speed signals, while two axial conductive elements conducting a differential signal is useful in canceling any noise or interference that penetrates the shielding. Moreover, shielding prevents “crosstalk” between shielded conductors placed in close proximity with one another, and facilities the construction of tightly spaced arrays. The interface elements 80, 82 pass the signals between the array 76 and boards 72, 74 while maintaining the integrity of the shielded geometric arrangement of the conductive elements through the connection interface.
Connector assembly 70 also capitalizes on the benefits of elastomeric connectors, e.g., compressible interface elements 80, 82, in providing high frequency data and/or communications connections between circuit boards 72, 74. In doing so, connector assembly 70 requires no soldering. Also, no soldering or special skill is required to remove and replace one of the compressible interface elements 80, 82 or signal array 76. A user need only remove the fasteners, reposition the new interface elements and/or signal array, and reinstall the fasteners. Connector assembly 70 also improves the replacement and serviceability of high-speed data and/or communications connections. There are also no pins to bend or break in the connector, and “crosstalk” qualities are improved at the connector assembly.
Referring now to
Shielded conductor 146 may, for example, be lengths of semi-rigid coax or twinax cables, including one or two inner or axial conductive elements, respectively, and a conductive outer structure. Examples of signal arrays including shielded conductors with one and two axial conductive elements will be described in
For example, in one embodiment, circuit boards 132, 134 include at least one pair of corresponding land areas including one central conductive core area. Examples of corresponding lands areas including one central conductive core area located on circuit boards were shown in
In another embodiment, circuit boards 132, 134 include at least one pair of corresponding land areas including two central conductive core areas. Examples of corresponding land areas including two central conductive core areas located on circuit boards were shown in
With the benefit of the foregoing and, more specifically, connector assemblies 10 and 70, shown in
Still referring to
Circuit boards 132, 134 may also be a motherboard and a daughter card, respectively. In such an embodiment, circuit board 132 may include a processor, e.g., microprocessor, and traces to interconnect numerous circuit packs using multiple connector assemblies described herein. Circuit board 134, as well as other similar circuit boards, may include numerous electrical components configured to perform some function, and also include connector assemblies described herein.
Other embodiments or applications, which lend themselves to two substantially perpendicular circuit boards, will readily appear to those of skill in the art.
Referring now to
Each block 152a-d may be constructed by forming pieces of semi-rigid coax at approximately 90-degree angles and casting or molding the coax sections into a non-conductive substance, such as a LCP 159. The conductors 154 are presented at the face surface in a generally co-planar arrangement. The contact or face surfaces 160 may then be machined to improve the co-planarity of the shielded conductors 154 and the interface between the shielded conductors 154 and the compressible interface elements, such as compressible interface elements 138, 140 shown in
In some embodiments, signal array 150 may further comprise a clip or band 162. Clip 162 includes ribs 164, while blocks 152a-d include notches 166, corresponding to ribs 166. Clip 162 functions to holds blocks 152a-d together, and aligned, when pressure is applied to signal array 150, such as, for example, clip 141 does when pressure is applied to signal array 136 shown in
Referring now to
Each block 172a-d may be constructed by forming pieces of semi-rigid twinax at approximately 90-degree angles and casting or molding the twinax cables into a non-conductive substance, such as LCP 179. The contact surfaces 180 may then be machined to improve the co-planarity of the shielded conductors 174 and the interface between the shielded conductors 174 and compressible interface elements, such as compressible interface elements 138, 140 shown in
In some embodiments, signal array 170 may also comprise a clip or band 182. Clip 182 includes ribs 184, while blocks 172a-d include corresponding notches 186. Clip 182 functions to holds blocks 172a-d in alignment when pressure is applied to signal array 170, such as pressure is applied to signal array 136 shown in
Those skilled in the art will appreciate that although signal arrays 150, 170 are constructed as blocks 152a-d, 172a-d, respectively, other embodiments of the present invention may be built using similarly functioning signal arrays having wafer type construction. An example of wafer type construction was shown in
Those skilled in the art will also appreciate that a signal array, irrespective of the type of shield conductor used, may be constructed having any size desired. Thus, for example, a signal array need not be constructed having a four-by-four array as shown herein in
Referring once again to
Pressure may be applied using a variety of fasteners. For example, and as shown in
Likewise, connector 138 is placed between corresponding land areas, e.g., coaxial or twinaxial, on circuit board 132 and shielded conductors 146 in signal array 136, aligning the central conductive core areas and the conductive outer structure areas of the land areas on circuit board 132 with the axial conductive element(s) and the outer conductive element of shielded conductors 146, respectively.
Such alignment may be achieved in a variety of ways. For example, and as also shown in
Pressure is also applied to compressible interface element 138 to compress compressible interface element 138 such that the conductive elements within compressible interface element 138 provide electrical connection from land areas on circuit board 132 through the conductive elements to shielded conductors 146. Such pressure may be provided by latch 204 mounted to circuit board 134, that articulates and engages slide 202, applying pressure to compressible interface element 138.
When compressible interface elements 138, 140 are compressed, those conductive elements contacting the outer conductive elements of shield conductors 146 and the conductive outer structure areas of land areas on circuit boards 132, 134 form a shield around, or “shield”, those conductive elements contacting the axial conductive elements of shield conductors 146 and the central conductive core areas of the land areas on circuit boards 132, 134. Thus, when compressible interface elements 138, 140 are compressed, conductive elements of compressible interface elements 138, 140 “extend” the geometric arrangement and/or shielding of shield conductors 146 through to land areas, or the surface, of circuit boards 132, 134.
Shielded conductors 146 accompanied by compressible interface elements 138, 140 that extended the shielding of those conductors may be used for single-ended or differential signals, based on the number of axial conductive element in a shielded conductor, such as high-speed data and/or communications signals. Shielding is particularly useful in preventing interference when using such high-speed or high frequency signals. Moreover, shielding prevents “crosstalk” between shielded conductors placed in close proximity with one another, and facilities the construction of dense or tightly spaced arrays of shielded conductors.
In addition, connector assembly 130 capitalizes on the benefits of elastomeric connectors, e.g., compressible interface elements 138, 140, in providing high frequency data and/or communications connections between circuit boards 132, 134. In doing so, connector assembly 130 requires no soldering. Further, no soldering or special skill is required to remove and replace one of the compressible interface elements 138, 140 or the signal array 136. A user need only release latch 204, remove circuit board 134 from slides 202 and frame 200, and/or remove fasteners 144, reposition the new compressible interface elements 138, 140 and/or signal array 136, and reinstall the fasteners 144 and circuit board 134. Also, connector assembly 130 includes no pins that may be bent or broken in inserting circuit board 134 in slides 202, resulting in a failure of the product the circuit boards 132, 134 are included in, either under production test or in the possession of a user or consumer. Connector assembly 130 also extends the geometric arrangement of the shielded conductors 146 in signal array 136 through connector assembly 130 to the surface of the circuit boards 132, 134. By extending the geometric arrangement, with its inherent shielding, crosstalk between shield conductors in the array is reduced, while the variation in impedance with changes in frequency of each respective shielded conductor 18 is also reduced. Thus, connector assembly 130 improves the replacement and serviceability of high-speed data and/or communications connections.
The individual conductors or cables 204 of each array 202a, 202b include one or more inner conductive elements and an outer conductive element. In a coaxial configuration, as illustrated in
In the embodiment of the connector assembly 206a, 206b, as illustrated in
Referring to
For the purposes of alignment, the bodies or blocks 206a, 206b utilize alignment pins 222 and corresponding alignment openings 224 to ensure that the inner conductive elements of the cables of one array interface properly with the inner conductive elements of the other arrays. The outer conductive elements are also similarly aligned. Appropriate openings 226 are utilized to receive appropriate fasteners, such as jackscrews, to hold the bodies 206a, 206b together and thus compress the compressible interface element 220 to provide a proper electrical connection between the arrays. As may be appreciated, the present invention provides a quick connect and quick disconnect connector assembly that does not require significant amounts of force to provide a proper signal interface, nor does it provide the male/female insertion requirements utilized with typical co-axial or pin-type connectors. Because of the unique configuration of the connector assembly of the invention, the high performance characteristics are maintained for high frequency signals.
The present invention provides significant performance, similar to coaxial connectors, while providing its other advantages as noted herein. For example, the VSWR measurement, made through two mated bodies and the interface element, was 1.07: 1, up to 20 GHz. This is similar to the VSWR in a typical coax cable. Furthermore, the impedance measured through the mated bodies and interface element was around 50 Ohms±3 Ohms, which is comparable to a typical coaxial connector.
The insertion loss and cross talk characteristics were also favorable for the invention. Measuring an insertion loss through a 3-foot coaxial cable with and without the connector of the invention yielded an insertion loss around −0.7 dB. The cross talk, up to 40 GHz, was low enough to certify the nature of a true RF path through the connector assembly of the invention. Specifically, the cross talk measured by injecting a signal in a cable at one side of the mated connector bodies and interface element, and measuring a signal at an adjacent cable on the other side of the connector assembly yielded a signal about −80.0 dB down from the input signal. This is similar to what is achieved in a coax cable.
a and 12b illustrate proper connection of the connector assembly 20 in order to compress the interface element 220 and provide the desired connection.
In the embodiment of
Turning to
Referring again to
Referring to
In one embodiment of the invention as shown in
In the embodiment shown in
Thus, in accordance with one aspect of the invention, the geometric arrangement of the inner and outer conductive elements is presented at the respective face surface of the connector bodies 206a, 206b. In combination with the compressible interface element, such as an elastomeric connector interface 220, the coplanar center conducto0rs and ground referenced ensure that high frequency RF signals may be passed from array 202a to the array 202b, or vice versa, while maintaining desirable performance characteristics in the connector assembly 200.
As illustrated in
Specifically, the signal bearing elements 252 utilizes a plurality of inner conductive traces 254 and outer conductive traces 256. As is conventional, the inner conductive traces 254 may represent signal conductors, wherein the outer conductive traces 256 may represent shielding or a ground reference for the signals on the traces 254. The area 258 between the inner and outer conductor traces is nonconductive may or may not include a separate dielectric material within the circuit board construction. Generally, the circuit board 250 may be formed in any suitable manner known to a person of ordinary skill in the art with respect to circuit boards, wherein conductive metal traces are deposited or otherwise formed within a multiple layer construction. The section 251 of the circuit board that contains the signal-bearing elements is at least one of raised, flush or countersunk with respect to surface 253 of the circuit board. The embodiment of
A compressible interface element 220 may be sized and configured to overlay the signal bearing elements 252 of circuit board 250 as illustrated in
The embodiment of the invention illustrated in
While the present invention has been illustrated by the description of the embodiments thereof, and while the embodiments have been described in considerable detail, it is not the intention of the applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details of representative apparatus and method, and illustrative examples shown and described. Accordingly, departures may be made from such details without departure from the spirit or scope of applicant's general inventive concept.
This application is a Continuation-In-Part application of U.S. patent application Ser. No. 10/702,192, filed Nov. 5, 2003 now U.S. Pat. 7,074,047 and entitled “Zero Insertion Force High Frequency Connector,” which application is incorporated herein by reference in its entirety.
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| Number | Date | Country | |
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| Number | Date | Country | |
|---|---|---|---|
| Parent | 10702192 | Nov 2003 | US |
| Child | 11133862 | US |
