Abstract:
An embodiment of a cable system includes a cable that has a conductor, a power layer and dielectric material. The conductor is operative to carry a signal, the dielectric material is located at least partially between the conductor and the power layer, and the power layer is operative as ground. The power layer is formed of a conductive material and includes a first region and an adjacent second region. The first region includes a greater amount of the conductive material than the second region so that the power layer is less resistant to bending along the second region than along the first region. Methods and other systems are also provided.

Description:
BACKGROUND  
         [0001]    A flex cable is an impedance-controlled cable that is used to connect two components, such as printed circuit boards (PCBs), that are oriented in such a manner that directly connecting the components to each other is impractical. As the name implies, a flex cable is flexible and, thus, can be twisted and/or bent to accommodate interconnection of the components. Care must be taken, however, to ensure that such a flex cable is not bent beyond a minimum bend radius.  
           [0002]    A typical flex cable is constructed of multiple layers of material, including a signal layer, a dielectric layer, and a power layer. The signal layer typically is formed of conductors, e.g., copper conductors, that are positioned in a generally planar arrangement, with each of the conductors being capable of carrying a separate signal. One or more dielectric layers surround the signal layer so that the conductors are spaced from the power layer, which functions as ground. Typically, the power layer is a thin plate of material, such as copper.  
           [0003]    As the amount of material used in the signal and/or power layers of a flex cable increases, the resistance of the flex cable to bending and/or twisting also typically increases. This can be problematic, particularly when an increased amount of material is required to provide an appropriate number of conductors while attempting to provide enough flexibility for the intended application.  
         SUMMARY  
         [0004]    An embodiment of a cable system includes a cable that has a conductor, a power layer and dielectric material. The conductor is operative to carry a signal, the dielectric material is located at least partially between the conductor and the power layer, and the power layer is operative as ground. The power layer is formed of a conductive material and includes a first region and an adjacent second region. The first region includes a greater amount of the conductive material than the second region so that the power layer is less resistant to bending along the second region than along the first region.  
           [0005]    Another embodiment of a cable system includes a cable. The cable incorporates a power layer that is operative as ground. The power layer is formed of a conductive material and includes multiple first locations and multiple second locations. Each of the first locations includes an amount of conductive material greater than the second locations so that the power layer is more resistant to bending at the first locations than at the second locations.  
           [0006]    Another embodiment of a cable system includes a flex cable having means for enabling the flex cable to bend preferentially along an axial-bending region, the axial-bending region being offset with respect to a longitudinal axis of the flex cable.  
           [0007]    An embodiment of a method for forming a cable systems comprises providing a power layer including at least a first region of reduced material content and forming a flex cable with the power layer.  
           [0008]    An embodiment of a method for electrically interconnecting components comprises providing a flex cable having a power layer that includes at least a first region of reduced material content, providing a first component and a second component that are to be electrically interconnected to each other, and electrically interconnecting the first component and the second component with the flex cable. 
       
    
    
     BRIEF DESCRIPTION. OF THE DRAWINGS  
       [0009]    [0009]FIG. 1 is a schematic, plan view of an embodiment of a cable system.  
         [0010]    [0010]FIG. 2 is a schematic diagram of the embodiment of the cable system of FIG. 1, as viewed along section line  2 - 2 .  
         [0011]    [0011]FIG. 3 is a schematic diagram of the embodiment of the cable system of FIGS.  1 - 2 , showing the cable being bent from the x-y plane.  
         [0012]    [0012]FIG. 4 is a schematic diagram of the embodiment of the cable system of FIGS.  1 - 3 , showing detail of the power layer.  
         [0013]    [0013]FIG. 5 is a schematic diagram of the embodiment of the power layer of FIG. 4, as viewed along section line  5 - 5 .  
         [0014]    [0014]FIG. 6 is a schematic diagram of another embodiment of a power layer as viewed in cross-section.  
         [0015]    [0015]FIG. 7 is a schematic diagram of another embodiment of a power layer.  
         [0016]    [0016]FIG. 8 is a schematic diagram of another embodiment of a power layer.  
         [0017]    [0017]FIG. 9 is a schematic diagram depicting two representative components that are electrically interconnected using an embodiment of a cable system.  
         [0018]    [0018]FIG. 10 is a flowchart depicting an embodiment of a method for forming a cable system.  
         [0019]    [0019]FIG. 11 is a flowchart depicting an embodiment of a method for electrically interconnecting components.  
     
    
     DETAILED DESCRIPTION  
       [0020]    As shown in FIG. 1, an embodiment of a cable system  10  includes a cable assembly  100 . The cable assembly  100  includes a cable  101 , upper surface  102  and side surfaces  103 ,  104  of which are shown. The constituent components of the embodiment of the cable assembly of FIG. 1 will be described with respect to FIG. 2.  
         [0021]    Cable  101  is coupled to a connector at each of its ends. In particular, connector  105  is coupled to end  106 , and connector  107  is coupled to end  108 . Note, connectors  105  and  107  can be selected from among various types of connectors. By way of example, and not limitation, FC, SCSI and SATA connectors can be used.  
         [0022]    Each of the connectors  105 ,  107  is sized and shaped to mate with a corresponding connector I  10 ,  112  of a respective component  1   14 ,  116 . In FIG. 1, components  1   14  and  116  are each configured as a printed circuit board (PCB). However, components of various other types can be used. Specifically, the components need only be configured to communicate with each other, such as via cable assembly  100 .  
         [0023]    In FIG. 2, the sides, i.e., upper surface  102 , bottom surface  118  and side surfaces  103  and  104 , of the cable  101  are shown. Also shown in FIG. 2, cable  101  includes multiple conductors  202  that span the length of the cable, and which communicate with the connectors ( 105 ,  107 ). Typically, each of the conductors  202  is spaced from other conductors, as well as from the power layer  204 . Note, power layer  204  typically functions as ground. The interstices formed between the various conductors  202  and the power layer  204  may be filled by dielectric material  206 , which can also form a protective exterior coating that surrounds the conductors  202  and power layer  204 . Note, various numbers and configurations of conductors, power layers and dielectric material can be used.  
         [0024]    [0024]FIG. 3 is a schematic diagram that depicts a representative portion of cable  101  of FIG. 1. As shown in FIG. 3, cable  101  bends preferentially from the xy plane. Note that cable  101  is bent at location  412  at a bend radius that is smaller than the minimum bend radius of a conventional flex cable. Thus, not only does the embodiment of FIGS.  1 - 3  bend preferentially at location  412 , the bending may be to a degree that is not achievable in conventional flex cables. The structural characteristics that enable this preferential bending will now be described with respect to FIG. 4.  
         [0025]    A representative portion of cable  101  and, in particular, power layer  204  (FIG. 2), is shown in FIG. 4. Power layer  204  is formed of a conductive material, such as copper. Power layer  204  has a longitudinal axis  402 , a top surface  403 , a bottom surface  404  (FIG. 5), and side surfaces  405 ,  406 . Power layer  204  also has axial-bending regions, e.g., axial-bending regions  408 , 410  and  412 , that are transverse to longitudinal axis  402 . The axial-bending regions  408 ,  410  and  412  contain less material than regions  414 ,  416 ,  418  and  420 , which are located adjacent to the axial-bending regions. Because of the disparity in the amount and location of material forming the power layer, the cable tends to bend about the axial-bending regions in response to a bending force. In other words, regions  414 , 416 ,  418  and  420 , each of which also extends generally transverse to longitudinal axis  402 , resists bending to a greater extent than the axial-bending regions.  
         [0026]    Note that the axial-bending regions of a power layer can be provided in various manners. By way of example, the lack of material associated with an axial-bending region  412  are formed by voids  422 ,  424  and  426 .  
         [0027]    As shown in FIG. 5, voids  422 ,  424  and  426  extend through the power layer  204  from the top surface  403  of the power layer  204  to the bottom surface  404  of the power layer  204 . Note, although the three voids  422 ,  424  and  426  are depicted in FIG. 5 as being substantially uniform with respect to size and shape, various sizes, shapes and/or numbers of voids can be used in a power layer.. For example, sizes and/or shapes that lack uniformity can be used.  
         [0028]    In contrast, other embodiments can include one or more recesses, i.e., locations where the material of the power layer is thinner than the material of adjacent locations. FIG. 6 schematically depicts a cross-sectional view of an embodiment of a power layer that includes recesses.  
         [0029]    As shown in FIG. 6, power layer  602  includes recesses  604 ,  606  and  608 . Note, although the recesses are depicted in FIG. 6 as being substantially uniform in size and shape, various configurations of recesses can be used. Also note that, in some embodiments, combinations of recesses and voids can be used to form an axial-bending region.  
         [0030]    Another embodiment of a power layer that can be used in a cable system is depicted schematically in FIG. 7. As shown in FIG. 7, power layer  702  has a longitudinal axis  703  and is formed of multiple strips of material. In particular, the power layer  702  is formed of multiple strips of material that are interwoven to form regions that include greater amounts of material than adjacent regions. Specifically, the power layer  702  includes generally longitudinally-extending strips, e.g., strips  704 ,  706  and  708  and generally transversely-extending strips, e.g., strips  710 ,  712 ,  714 ,  716  and  718 . These interwoven strips of material are spaced from each other to form voids, e.g., void  720 . Such a void includes less material than a location at which only a single strip of material is located, such as region  722 , and much less material than included in region  724 , which includes an overlapping portion of strips  706  and  712 . The voids-form axial-bending regions, e.g., axial-bending region  724 , about which the power layer  702  bends preferentially.  
         [0031]    Note that various numbers and shapes of strips can be used to form a power layer. Additionally, in some embodiments, at least some of the strips may not be spaced from each other to form voids.  
         [0032]    Another embodiment of a power layer is depicted schematically in FIG. 8. As shown in FIG. 8, power layer  802  includes a longitudinal axis  804  and axial-bending regions, e.g., axial-bending region  806 . Each of the axial-bending regions is angularly offset with respect to the longitudinal axis  804 . Specifically, axial-bending region  806  is formed by a row  808  of voids. Row  808  extends diagonally across the power layer  802  and includes voids  810 ,  812 ,  814  and  816 . Note, each of the rows of voids defines an independent axial-bending axis, such that the power layer can be bent about each of the rows.  
         [0033]    An embodiment of a method for forming a cable system is depicted in FIG. 9. As shown in FIG. 9, the method may be construed as beginning at block  902 , where a power layer that includes at least a first region of reduced material content is provided. In block  904 , a flex cable is formed with the power layer.  
         [0034]    An embodiment of a method for interconnecting components is depicted in the flowchart of FIG. 10. As shown in FIG. 10, the method maybe construed as beginning at block  1002 , where a flex cable having a power layer that includes at least a first region of reduced material content is provided. In block  1004 , components that are to be electrically interconnected are provided. Thereafter, the components are electrically interconnected with the flex cable. (block  1006 ).  
         [0035]    [0035]FIG. 11 schematically depicts components that are electrically interconnected by an embodiment of a cable system. In particular, component  1102  electrically communicates with component  104  via an embodiment of a cable assembly  100 . The embodiment of the cable assembly  100  of FIG. 11 includes an embodiment of a power layer (not shown in FIG. 11) similar to the power layer  802  of FIG. 8. In particular, the power layer of the cable system  100  of FIG. 11 includes axial-bending regions that are angularly offset with respect to the longitudinal axis of the cable. As such, the cable  101  is able to bend at the angle depicted. Specifically, cable  101  extends outwardly from component  1102  and turns approximately 90 degrees so that it can connect to component  1104 .  
         [0036]    It should be emphasized that the above-described embodiments are merely possible examples of implementations. Many variations and modifications may be made to the above-described embodiments. All such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the following claims.