Abstract:
A system includes an interconnect that is seated and retained in a connector using a number of bumpletts arranged in the system to exert a cam force that encourages retention of the interconnect in the connector. The connector is coupled to a target board. The connector comprises a spacer nest and a pair of boards, such as printed circuit boards, that may contain electrical circuitry. The cam bumpletts may reside at the interconnect, or on either or both of the pair of boards of the connector.

Description:
FIELD OF THE INVENTION 
   The invention relates to electrical connectors used to facilitate the connection of electrical signals between electrical circuit devices. In particular, the invention relates to a cam connector capable of engaging and retaining through application of a bumplett-induced camming force an interconnect inserted into it. 
   BACKGROUND OF THE INVENTION 
   It is often necessary, particularly in electrical test and measurement applications, to be able to make available the electrical signals of a particular electrical device, such as a printed circuit board, to another electrical device. In such applications, many test and measurement devices, including logic analysis systems and problems, require the use of a high density interconnect to interface with a device under test, such as a printed circuit board, via an electrical connector. 
   In the connection of electrical circuit devices, such as printed circuit boards, an interconnect that is seated in a connector with contacts molded to match the design of the connector is commonly used. Using this technique forces a designer to use standard off-the-shelf pre-configured molded connectors or to design and tool a customized molded connector. Use of standard off-the-shelf pre-configured molded connectors may not be customized since they are pre-configured to a certain specification and are thus not flexible. The design and tooling required to create a customized molded connector is thus both costly and time consuming. Moreover, a customized molded connector is not flexible, since each connector of a different size and/or specification would have to be designed and tooled. Because of the time and cost associated with a customized molded connection, it is not an efficient solution for low volume production where only a small number of connectors need to be created. 
   Also in test and measurement applications, it is desirable to locate electrical circuitry as close to the target being tested as possible, particularly when dealing with fast signals. In the testing of electrical devices, a termination network is commonly used to minimize reflections between the device under test (target) and the test and measurement device or probe interconnecting to the target. Since molded connectors do not allow electrical circuitry to be placed at the connection point of the connector contact area, there is no provision for having connector termination networks at the interface to the target, thereby causing the termination network to be located further away from the target than is preferable. In this configuration, the physical location of the termination network is important. The spacing of termination networks or circuitry away from the interconnect contact area can introduce unwanted parasitic electrical effects, particularly when measuring fast signals, which can have an adverse impact on accurate signal measurement. Thus, using molded connectors forces termination network circuitry or other needed electrical circuitry to be located further away from the target than is preferable. 
   Molded connectors additionally have several deficiencies because they are tooled. Using a tooling technique to create a molded connector prohibits creation of an extremely low profile molded connector which in turn increases the required overall profile size of an electrical device to which the connector is attached. Additionally, in molded connectors, the contacts are typically molded into the connector itself Over time, these contacts tend to oxidize and corrode which may affect the electrical performance of the electrical circuitry. 
   SUMMARY OF THE INVENTION 
   The invention includes a connector, having a nest spacer element, a substantially planar first board, and a substantially planar second board. The nest spacer element has a first substantially planar surface, a second substantially planar surface, and a recessed portion that is contiguous to the first and second substantially planar surfaces operable to accommodate an interconnect. The substantially planar first board has a first outer surface and a first inner surface coupled to the first substantially planar surface of the nest spacer element. The substantially planar second board has a second outer surface and a second inner surface coupled to the second substantially planar surface of the nest spacer element, with at least one of the first and second boards having a plurality of connector signal traces arranged along one or more of the corresponding inner and outer surfaces. The insertion of the interconnect into the recessed portion of the nest spacer element produces a camming force between the connector and the interconnect caused by a plurality of bumpletts located on the connector. 
   The invention further encompasses a connector system having an interconnect and a connector. The interconnect has a substantially planar surface and a plurality of interconnect signal traces that terminate at a coupling end of, the interconnect. The connector comprises a nest spacer element, a substantially planar first board, and a substantially planar second board. The nest spacer element has a first substantially planar surface, a second substantially planar surface, and a recessed portion that is contiguous to the first and second substantially planar surfaces operable to accommodate an interconnect. The substantially planar first board has a first outer surface and a first inner surface coupled to the first substantially planar surface of the nest spacer element. The substantially planar second board has a second outer surface and a second inner surface coupled to the second substantially planar surface of the nest spacer element, with at least one of the first and second boards having a plurality of connector signal traces arranged along one or more of the corresponding inner and outer surfaces. The insertion of the interconnect into the recessed portion of the nest spacer element produces a camming force between the connector and the interconnect caused by a plurality of bumpletts located on at least one of the interconnect, the first board, and the second board. The system can further encompass a target board to which the connector is coupled. 
   The invention can further include a cam connection system having an interconnect, a target board, and a connector housing. The interconnect has a plurality of interconnect signal traces that terminate at a coupling end of the interconnect. The target board has a plurality of target signal traces. The connector housing is coupled to the target board and has a portion operable to accommodate the interconnect parallel to the target board. The insertion of the coupling end of the interconnect into the connector housing produces a camming force between the connector housing, the target board, and the interconnect caused by a plurality of bumpletts located on at least one of the connector housing, the interconnect, and the target board thereby coupling the plurality of target signal traces to the plurality of interconnect signal traces. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The novel features believed characteristic of the invention are set forth in the claims. The invention itself, however, as well as the preferred mode of use, and further objects and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawing(s), wherein: 
       FIG. 1  is a perspective inside view of a substantially planar first board in accordance with certain embodiments of the invention. 
       FIG. 2  is a perspective outside view of the substantially planar first board in accordance with certain embodiments of the invention. 
       FIG. 3  is a perspective inside view of a substantially planar second board in accordance with certain embodiments of the invention. 
       FIG. 4  is a perspective outside view of the substantially planar second board in accordance with certain embodiments of the invention. 
       FIG. 5  is a perspective view of a spacer nest element in accordance with certain embodiments of the invention. 
       FIG. 6  is a front view of the spacer nest element in accordance with certain embodiments of the invention. 
       FIG. 7  is a side view of the spacer nest element in accordance with certain embodiments of the invention. 
       FIG. 8  is a top view of the spacer nest element in accordance with certain embodiments of the invention. 
       FIG. 9  is an exploded view of a connector in accordance with certain embodiments of the invention. 
       FIG. 10  is a perspective view of an interconnect in accordance with certain embodiments of the invention. 
       FIG. 11  is a perspective view of a target board in accordance with certain embodiments of the invention. 
       FIG. 12  is a perspective view of a cam connection system in accordance with certain embodiments of the invention. 
       FIG. 13  is a section view of the cam connection system in accordance with certain embodiments of the invention. 
       FIG. 14  is a perspective view of a cam connection system in accordance with certain embodiments of the invention. 
       FIG. 15  is a perspective view of a cam connection system in accordance with certain embodiments of the invention. 
       FIG. 16  is a section view of the cam connection system in accordance with certain embodiments of the invention, showing a termination network coupled to the connector. 
       FIG. 17  is a perspective outside view of a substantially planar board in accordance with certain embodiments of the invention, showing a termination network coupled to the connector. 
       FIG. 18  is a perspective view of a cam connection in accordance with certain embodiments of the invention. 
       FIG. 19  is a section view of a cam connection system in accordance with certain embodiments of the invention. 
       FIG. 20  is a section view of the cam connection system in accordance with certain embodiments of the invention. 
       FIG. 21  is an exploded view of the cam connection system in accordance with certain embodiments of the invention. 
   

   DESCRIPTION OF THE INVENTION 
   While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail one or more specific embodiments, with the understanding that the present disclosure is to be considered as exemplary of the principles of the invention and not intended to limit the invention to the specific embodiments shown and described. In the description below, like reference numerals are used to describe the same, similar or corresponding parts in the several Views of the drawings. 
   The terms “a” or “an”, as used herein, are defined as one or more than one. The term “plurality”, as used herein, is defined as two or more than two. The term “another”, as used herein, is defined as at least a second or more. The terms “including” and/or “having”, as used herein, are defined as comprising (i.e., open language). The term “coupled”, as used herein, is defined as connected, although not necessarily directly, and not necessarily mechanically. 
   Referring first to  FIGS. 1 ,  2 ,  3  and  4 , inner and outer perspective views of a substantially planar first board  100  and a substantially planar second board  200  in accordance with certain embodiments of the present invention are shown; the first and second boards  100  and  200 , together with spacer nest  300 , together form a connector as will be clear in the description of later figures. The substantially planar first board  100 , such as a printed circuit board, has a first bottom surface  140 , a first inner surface  150 , and a first outer surface  160  as shown. The substantially planar second board  200 , which may also be a printed circuit board, has a second bottom surface  240 , a second inner surface  250 , and a second outer surface  260  as shown. As used herein, reference to an “inner surface” refers to that surface of the board that faces towards the inside of the spacer nest  300  when attached to it, whereas reference to an “outer surface” refers to that surface of the board that faces towards the outside of the connector when the board is attached to the spacer nest. The boards are configured such that at least one of the first  100  and second  200  boards has a plurality of connector signal traces,  110  and  210  respectively, arranged along one or more of the inner and outer surfaces. An example of a board configuration without any signal traces is shown and described later in  FIG. 21   
   The plurality of electrical traces,  110  and  210 , on the first inner surface  150  and second inner surface  250  each have a via,  120  and  220 , to provide electrical continuity of an electrical trace between the first outer surface  160  and the second outer surface  260  as shown. The plurality of electrical traces  110  and  210  each are suitable to be coupled to any nominal reference voltage level, of which ground is one example, if so desired, in addition to electrical signals. The electrical traces may be made of gold plated brass or other suitable electrical conductor material. 
   A plurality of bumpletts  130  and  230  are shown operably attached to one or more of the electrical traces  110  and  210  along the inside surfaces of the boards  100  and  200 , respectively. As shown, these bumpletts need not be placed on every signal trace  110 ,  210 . Placement of the bumpletts should simply support the generation of a camming force upon insertion of an interconnect into the recessed portion of the housing. Insertion of the interconnect will push the bumpletts against the signal traces, in a wiping motion, resulting in a camming force, similar to a spring-loaded force, that will assist in retaining the interconnect into the connector. 
     FIGS. 3 and 4  show an optional keying element  270  extending vertically from the bottom surface  240  of the second board  200 . This optional keying element operates to ensure the proper orientation of the assembled connector to a target board, as will be described. 
   In the particular embodiments illustrated in  FIGS. 1-4 , it can be seen that along the inner surface of a board, the connector signal traces  110 ,  210  are aligned near the top of the inside surface of the board to be accessible to an interconnect that may be inserted into the recess  320  of the connector; the u-shaped middle portion  310  of spacer nest  300 , shown in  FIG. 5 , argues for this placement of the signal traces along the inside surface of the board, although different configurations of the connector housing might suggest different placement of the signal lines. Similarly, the arrangement of the connector signals traces  110 ,  210  along most of the outer surface of the boards is but an example, although this arrangement does support the arrangement of one or more discrete electrical components or other circuitry along the outside of the connector, as will be described. 
   Referring to  FIGS. 5 ,  6 ,  7 , and  8 , perspective, front, side, and top views, respectively, of a spacer nest element  300  in accordance with certain embodiments of the present invention are shown. The spacer nest element  300  has a middle portion  310  with a first substantially planar surface  312  and a second substantially planar surface  314 . It can be seen that the middle portion  310  additionally may have a recessed portion  320 , in this embodiment having a “U” shape, as shown.  FIG. 5  shows an optional keying element  330 , a first peripheral wall  340 , and a second peripheral wall  350  of the spacer nest element  300 . The keying element  330  is shown extending vertically from the bottom of the spacer nest element. The first and second peripheral walls  340  and  350  are coupled perpendicularly and coextensively to the middle portion  310  as shown. 
   Referring to  FIG. 9 , an exploded view of a connector in accordance with certain embodiments of the present invention is shown. The connector  400  has a nest spacer element  300 , a substantially planar first board  100 , and a substantially planar second board  200  as shown. These parts of the connector have been previously described.  FIG. 9  illustrates the alignment of these parts with respect to one another, particularly the alignment of the boards  100 ,  200  inside the peripheral walls previously discussed. 
   Referring to  FIG. 10 , a perspective view of an interconnect in accordance with certain embodiments of the invention is shown. The interconnect  500  has a substantially planar surface  510  and a plurality of interconnect signal traces  520  that terminate at a coupling end  550  of the interconnect as shown. A rigid flex circuit  530  is shown extending away from the coupling end  550  of the interconnect. One skilled in the art will appreciate, however, that the rigid flex circuit may be substituted for a printed circuit board, a cable, or any equivalent capable of carrying electrical signals. The interconnect may optionally contain a plurality of bumpletts shown and described later in  FIGS. 14 and 15 . 
   Referring to  FIG. 11 , a perspective view of a target board in accordance with certain embodiments of the invention is shown. The target board  600 , which may also be referred to as a device under test, has a plurality of target signal traces  610  (not shown) that are coupled to the connector signal traces  110  and  210  shown previously in  FIGS. 1 ,  2 ,  3  and  4  via a coupling means, such as reflowable solder bumps  610 . Optionally, the target board  600  may contain a first key coupling  630  and a second key coupling  620 , that is coupled to the optional keying element  330  of the nest spacer element  300  previously shown in  FIGS. 5 ,  6 , and  7  and the optional keying element  270  of the substantially planar second board  200 , respectively. It is advisable, but not required, to use keying so that the connector  400  cannot be coupled incorrectly to the target board  600 . 
   Referring to  FIGS. 12 and 13 , perspective and section views, respectively, of a cam connection system in accordance with certain embodiments of the invention are shown. The cam connection system  700  has an interconnect  500 , a connector  400 , and a target board  600  as shown. The plurality of vias,  120  and  220 , and plurality of bumpletts,  130  and  230 , of the substantially planar first  100  and second  200  boards are visible in FIG.  13 . Insertion of the interconnect  500  into the cavity of the connector  400  produces a camming force between the connector  400  and the interconnect  500 , due to the presence of one or more plurality of bumpletts  230  and  130  on the connector. After insertion the interconnect  500  on the bumpletts  130  and  230  on the connector  400  is coupled to a corresponding plurality of traces located on the interconnect  500 . The insertion causes bumpletts  130  and  230  to be pushed back against membranes  132  and  232 , respectively, into cavities  150  and  250 , respectively, thereby producing a camming force operable to encourage retention of interconnect  500  inside the connector  400 . Optionally, the plurality of bumpletts may be configured on one or more of the connector  400  or the interconnect  500 . 
   Referring to  FIG. 14 , a perspective view of a cam connection system in accordance with an alternate embodiment of the present invention is shown. The cam connection system  800  has an interconnect  810 , a connector  820 , and a target board  600  as shown. In this configuration, the interconnect  810  and connector  820  both contain a plurality of bumpletts  812  and  822 , respectively. As previously discussed, the bumpletts may be arranged as needed between the interconnect and the connector. 
   Referring to  FIG. 15 , a perspective view of a cam connection system in accordance with an alternate embodiment of the present invention is shown. The cam connection system  900  has an interconnect  910 , a connector  920 , and a target board  600  as shown. In this configuration, the interconnect  910  contains a plurality of bumpletts  912  and the connector  920  does not contain any bumpletts. Insertion of the interconnect  910  into the cavity of the connector  920  produces a camming force between the connector  920  and the interconnect  910 , due to the presence of one or more bumpletts  912  on the interconnect, shown on FIG.  16 . After insertion the plurality of bumpletts  912  on the interconnect  910  is coupled to a corresponding plurality of traces located on the connector  920 . The insertion causes bumpletts  912  to be pushed back against a membrane  914  into a cavity  916 , thereby producing a camming force operable to encourage retention of interconnect  910  inside the connector  920 . Optionally, the plurality of bumpletts may be configured on one or more of the connector  910  or the interconnect  920 . 
   Referring to  FIG. 16 , a perspective view of a cam connection system in accordance with an alternate embodiment of the present invention is shown. The cam connection system  1000  has an interconnect  910 , a connector  1010 , and a target board  600  as shown. In this configuration, one or both of the first and second boards of the connector  1010  may contain an electrical circuit or components  1012 , such as that which may be suitable for a termination network to minimize reflections between the target board  600  and the interconnect  910 .  FIG. 17 , a perspective outside view of a substantially planar board in accordance with an alternate embodiment of the present invention shows a closer view of electrical circuit or components  1012 . In this example, discrete electrical components, such as a stacked resistor-capacitor combination and a resistor, are placed on electrical traces that alternate with ground traces as shown. While such a configuration of discrete electrical components may be used to define one or more termination networks to reduce reflections at the interface, the invention is not limited to such a configuration as other configurations may additionally be used. In  FIG. 18 , a perspective view of a cam connection system in accordance with an alternate embodiment of the present invention shows a perspective view of the electrical circuit  1012  relative to the cam connection system. 
   Referring to  FIGS. 19 and 20 , a series of section views of a cam connection system in accordance with an alternate embodiment of the present invention is shown. The cam connection system  1100  has an interconnect  910 , a target board  1110 , and a connector housing  1120  as shown. In this configuration, the connector housing  1120  is coupled to the target board  1110  in such a manner as to accommodate insertion of interconnect  910  into cavity  1130  in a plane that is substantially parallel target board  1110 . Insertion of the interconnect  910  into the cavity  1130  of the connector housing  1120  produces a camming force between the connector housing  1120 , the target board  1110 , and the interconnect  910 , due to the presence of one or more bumpletts  912  on the interconnect. After insertion the plurality of bumpletts  912  on the interconnect  910  is directly coupled to a corresponding plurality of traces located on the target board  1110 . The insertion causes bumpletts  912  to be pushed back against membrane  914  into cavity  916 , thereby producing a camming force operable to encourage retention of interconnect  910  inside connector housing  1120 . Optionally, the plurality of bumpletts may be configured on one or more of the target board  1110 , the cam connection housing  1120 , or on other locations of the interconnect  910 . 
   Referring to  FIG. 21 , an exploded view of a connector in accordance with an alternate embodiment of the present invention is shown. In this configuration, it is demonstrated that one or more of the first and second boards that make up the connector may contain no electrical traces or electrical circuitry, as illustrated by board  1210  This does not interfere with the camming force produced by bumpletts when an interconnect is inserted into the connector. 
   While the invention has been described in conjunction with specific embodiments, it is evident that many alternatives, modifications, permutations and variations will become apparent to those of ordinary skill in the art in light of the foregoing description. Accordingly, it is intended that the present invention embrace all such alternatives, modifications and variations as fall within the scope of the appended claims.