PATENT DOCUMENT

Publication Number: US-10400364-B1
Application Number: US-201715677944-A
Country: US
Kind Code: B1

Title: Fabrics with conductive paths

Abstract:
A fabric-based item may have fabric with conductive strands and insulating strands. The conductive strands may form conductive signal paths and may be coupled to control circuitry. The conductive strands and insulating strands may be woven in a construction that allows multiple conductive strands to contact one another to form a low resistance signal path such as a power line, a data line, or a ground line. The fabric may have a two up and three down twill pattern, a two up and three down twill pattern, or other suitable pattern. The pattern may be selected so that groups of conductive weft strands or groups of conductive warp strands are in contact with one another. The conductive strands may have greater density than the insulating strands. For example, if the weft strands are conductive, the fabric may have a higher number of picks per inch than ends per inch.

Claims:
What is claimed is: 
     
       1. An item, comprising:
 insulating yarns that extend in a first direction; 
 conductive yarns that extend in a second direction, wherein the second direction is orthogonal to the first direction, wherein the conductive yarns are intertwined with the insulating yarns to form fabric having upper and lower surfaces, wherein the insulating yarns have portions on the upper surface of the fabric and portions on the lower surface of the fabric, wherein the portions on the upper surface of the fabric float over at least two conductive yarns to bring the at least two conductive yarns into contact with one another, and wherein a number of insulating yarns per inch in the fabric is less than a number of conductive yarns per inch in the fabric; and 
 control circuitry coupled to the conductive yarns. 
 
     
     
       2. The item defined in  claim 1  wherein the insulating yarns are warp yarns and the conductive yarns are weft yarns. 
     
     
       3. The item defined in  claim 1  wherein the insulating yarns are weft yarns and the conductive yarns are warp yarns. 
     
     
       4. The item defined in  claim 1  wherein a first and third of every five insulating yarns over a given conductive yarn is on the upper surface of the fabric and a second, fourth, and fifth of every five insulating yarns over the given conductive yarn is on the lower surface of the fabric. 
     
     
       5. The item defined in  claim 1  wherein a number of conductive yarns per inch is at least 150. 
     
     
       6. The item defined in  claim 1  wherein a plurality of the conductive yarns are electrically connected to one another to form a conductive signal path. 
     
     
       7. The item defined in  claim 6  wherein the conductive signal path comprises an electrical path selected from the group consisting of: a power line, a data line, and a ground line. 
     
     
       8. The item defined in  claim 7  wherein the fabric forms part of an electronic device cover. 
     
     
       9. The item defined in  claim 8  wherein the cover has a bend axis where the fabric bends and wherein the conductive signal path intersects with the bend axis. 
     
     
       10. An item, comprising:
 insulating warp strands; 
 conductive weft strands intertwined with the insulating warp strands to form fabric, wherein a first and second of every five insulating warp strands is on a top surface of the fabric and a third, fourth, and fifth of every five insulating warp strands is on a bottom surface of the fabric, wherein a first plurality of the conductive weft strands are electrically connected to one another to form a first conductive signal path, wherein a second plurality of the conductive weft strands are electrically connected to one another to form a second conductive signal path, and wherein the first and second conductive signal paths have different widths; and 
 control circuitry coupled to the conductive weft strands. 
 
     
     
       11. The item defined in  claim 10  wherein the conductive weft strands comprise metal plated strands. 
     
     
       12. The item defined in  claim 10  wherein each of the conductive weft strands comprises a bundle of conductive filaments and insulating filaments. 
     
     
       13. The item defined in  claim 10  wherein a number of conductive weft strands per inch is at least 150. 
     
     
       14. The item defined in  claim 10  wherein a number of insulating warp strands per inch in the fabric is less than a number of conductive weft strands per inch in the fabric. 
     
     
       15. The item defined in  claim 10  wherein the first and second conductive signal paths each comprise an electrical path selected from the group consisting of: a power line, a data line, and a ground line. 
     
     
       16. An item, comprising:
 a woven fabric having warp and weft strands, wherein three of every five warp strands is on a top surface of the fabric and two of every five warp strands is on a bottom surface of the fabric, and wherein the fabric has conductive portions that form electrical paths of different widths; and 
 control circuitry coupled to the electrical paths. 
 
     
     
       17. The item defined in  claim 16  wherein the warp strands are insulating strands, wherein the weft strands are conductive strands, and wherein the weft strands form the conductive portions of the fabric. 
     
     
       18. The item defined in  claim 17  wherein the conductive strands comprise silver plated yarn. 
     
     
       19. The item defined in  claim 17  wherein a number of warp strands per inch in the fabric is less than a number of weft strands per inch in the fabric. 
     
     
       20. The item defined in  claim 16  wherein the weft strands are insulating strands, wherein the warp strands are conductive strands, and wherein the warp strands form the conductive portions of the fabric. 
     
     
       21. The item defined in  claim 20  wherein a number of weft strands per inch in the fabric is less than a number of warp strands per inch in the fabric.

Description:
This application claims the benefit of provisional patent application No. 62/397,105, filed Sep. 20, 2016, which is hereby incorporated by reference herein in its entirety. 
    
    
     FIELD 
     This relates generally to fabrics and, more particularly, to fabrics with conductive paths. 
     BACKGROUND 
     Electronic devices often include signal paths for carrying electrical current. In some applications, it may be desirable to form parts of an electronic device from fabric. For example, a flexible electronic device may have fabric portions that allow the electronic device to bend and flex. 
     It can be challenging to form conductive signal paths in fabric items. The fabric may have portions that are plated with metal to form a conductive signal path, but the metal plating may be susceptible to damage after repetitive bending of the fabric. 
     SUMMARY 
     A fabric-based item may have fabric with conductive strands and insulating strands. The conductive strands may form conductive signal paths and may be coupled to control circuitry. The conductive strands and insulating strands may be woven in a construction that allows multiple conductive strands to contact one another to form a low resistance signal path such as a power line, a data line, or a ground line. 
     The fabric may have a two up and three down twill pattern, a two up and three down twill pattern, or other suitable pattern. The pattern may be selected so that groups of conductive weft strands or groups of conductive warp strands are in contact with one another. The conductive strands may have greater density than the insulating strands. For example, if the weft strands are conductive, the fabric may have a higher number of picks per inch than ends per inch. 
     In some applications, the fabric may be used as a cover for an electronic device. The cover may be flexible and may be bent to function as a stand for the electronic device. The fabric may have a bend axis around which the fabric folds when used as a stand. The conductive signal paths in the fabric may intersect with the bend axis. By weaving the conductive signal paths into the fabric, the conductive signal paths may be flexible and capable of withstanding the bending of the fabric. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of an illustrative item that may include fabric with conductive yarn in accordance with an embodiment. 
         FIG. 2  is a diagram showing how conductive yarn in a fabric may be coupled to control circuitry in accordance with an embodiment. 
         FIG. 3  is a cross-sectional side view of an illustrative fiber in accordance with an embodiment. 
         FIG. 4  is a cross-sectional view of an illustrative fiber with a core and an outer coating in accordance with an embodiment. 
         FIG. 5  is a cross-sectional view of an illustrative fiber with a core and two coating layers in accordance with an embodiment. 
         FIG. 6  is a cross-sectional view of an illustrative yarn formed from multiple fibers in accordance with an embodiment. 
         FIG. 7  is a cross-sectional view of an illustrative yarn in which conductive fibers are surrounded by insulating fibers in accordance with an embodiment. 
         FIG. 8  is a side view of illustrative weaving equipment that may be used to form fabric in accordance with an embodiment. 
         FIG. 9  is a top view of illustrative fabric having conductive signal paths such as a power line, a data line, and a ground line in accordance with an embodiment. 
         FIG. 10  is a top view of an illustrative fabric in which conductive weft strands have higher density than insulating warp strands in accordance with an embodiment. 
         FIG. 11  is a top view of an illustrative fabric in which conductive warp strands have higher density than insulating weft strands in accordance with an embodiment. 
         FIG. 12  is a cross-sectional side view of illustrative fabric in which an insulating strand floats over three conductive strands in accordance with an embodiment. 
         FIG. 13  is a weaving diagram of a two up and three down twill pattern with conductive weft strands and insulating warp strands in accordance with an embodiment. 
         FIG. 14  is a fabric having a construction of the type shown in  FIG. 13  in accordance with an embodiment. 
         FIG. 15  is a weaving diagram of a two up and three down twill pattern with conductive warp strands and insulating weft strands in accordance with an embodiment. 
         FIG. 16  is a fabric having a construction of the type shown in  FIG. 15  in accordance with an embodiment. 
         FIG. 17  is a weaving diagram of a two up and three down modified twill pattern with conductive weft strands and insulating warp strands in accordance with an embodiment. 
         FIG. 18  is a fabric having a construction of the type shown in  FIG. 17  in accordance with an embodiment. 
         FIG. 19  is a weaving diagram of a two up and three down modified twill pattern with conductive warp strands and insulating weft strands in accordance with an embodiment. 
         FIG. 20  is a fabric having a construction of the type shown in  FIG. 19  in accordance with an embodiment. 
         FIG. 21  is a weaving diagram of a three up and two down twill pattern with conductive weft strands and insulating warp strands in accordance with an embodiment. 
         FIG. 22  is a fabric having a construction of the type shown in  FIG. 21  in accordance with an embodiment. 
         FIG. 23  is a weaving diagram of a three up and two down twill pattern with conductive warp strands and insulating weft strands in accordance with an embodiment. 
         FIG. 24  is a fabric having a construction of the type shown in  FIG. 23  in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     An item such as a fabric-based item may contain fabric formed from intertwined strands of material. As shown in  FIG. 1 , for example, item  10  may contain fabric  12 . Item  10  may also include circuitry such as electrical components  14 . The circuitry of components  14  may include input-output devices such as buttons, touch sensors, light-based sensors such as light-based proximity sensors, force sensors, environmental sensors such as temperature sensors and humidity sensors, other sensors, status indicator lights and other light-based components such as light-emitting diodes for forming displays and other light-emitting structures, vibrators or other haptic output devices, etc. The circuitry of components  14  may also form control circuitry (e.g., processors, touch sensor circuits, etc.). Fabric  12  may, if desired, include conductive strands of material that are coupled to electrical components  14 , control circuitry formed from processors and other circuits in components  14 , and other circuitry in item  10 . The conductive strands may serve as signal paths that carry signals between input-output components and control circuitry and may serve as capacitive touch sensor electrodes and other conductive structures in item  10 . 
     The control circuitry formed from components  14  may include processors (e.g., microprocessors, microcontrollers, digital signal processors, baseband processors in wireless circuits, application-specific integrated circuits, and other control circuitry), may include control circuitry for processing sensor signals (e.g., capacitive touch sensor circuitry for gathering touch sensor data from capacitive sensor electrodes), and may include storage (e.g., volatile and non-volatile memory for storing data and code, etc.). 
     Item  10  may be a laptop computer, a computer monitor containing an embedded computer, a tablet computer, a cellular telephone, a media player, or other handheld or portable electronic device, a smaller device such as a wristwatch device, a pendant device, a headphone or earpiece device, a device embedded in eyeglasses or other equipment worn on a user&#39;s head, or other wearable or miniature device, a television, a computer display that does not contain an embedded computer, a gaming device, a navigation device, an embedded system such as a system in which electronic item  10  is mounted in a kiosk, in an automobile, airplane, or other vehicle, other electronic equipment, or equipment that implements the functionality of two or more of these devices. If desired, item  10  may be a removable external case for electronic equipment or other device accessory, may be a strap, may be a wrist band or head band, may be a removable cover for a device, may be a case or bag that has straps or that has other structures to receive and carry electronic equipment and other items, may be a necklace or arm band, may be a wallet, sleeve, pocket, or other structure into which electronic equipment or other items may be inserted, may be part of a chair, sofa, or other seating (e.g., cushions or other seating structures), may be part of an item of clothing or other wearable item (e.g., a hat, belt, wrist band, headband, shirt, pants, shoes, etc.), or may be any other suitable item that includes circuitry. 
     As shown in  FIG. 2 , item  10  may include fabric  12  and control circuitry  22  (e.g., control circuitry formed from components  14 , as described in connection with  FIG. 1 ). Fabric  12  may be woven fabric, knit fabric, braided material, felt, or other suitable fabric formed from intertwined strands of material. In the illustrative arrangement of  FIG. 2 , fabric  12  is woven fabric that is formed from warp strands  20  and weft strands  18 . Fabric  12  may include insulating strands such as strands  18 I and  20 I and may include conductive strands such as strands  18 C and  20 C. Conductive strands of material in fabric  12  may be used in conveying signals between control circuitry  22  and electrical components (see, e.g., illustrative electrical component  24 , which has a first terminal coupled to conductive strand  20 C and a second terminal coupled to conductive strand  18 C). 
     Components such as component  24  may be input-output components such as buttons, touch sensors, light-based sensors such as light-based proximity sensors, force sensors, environmental sensors such as temperature sensors and humidity sensors, other sensors, status indicator lights and other light-based components such as light-emitting diodes for forming displays and other light-emitting structures, vibrators or other haptic output devices, etc. In configurations such as these, circuitry  22  may gather sensor signals or other signals from components  24  using conductive strands in fabric  12  or may apply control signals to components  24  using conductive strands in fabric  12  (e.g., to light up light-emitting diodes in fabric  12  to display images or other light output on fabric  12 , to generate haptic output, etc.). 
     If desired, fabric  12  may include a grid of intersecting horizontally extending conductive strands (e.g., weft strands  18 C in the example of  FIG. 2 ) and perpendicular vertically extending conductive strands (e.g., warp strands  20 C in the example of  FIG. 2 ). The conductive paths (lines) in the grid formed from conductive strands  18 C and  20 C may serve as capacitive electrodes in a capacitive touch sensor (touch sensor grid). In this type of arrangement, control circuitry  22  may include capacitive touch sensor circuitry that is coupled to the conductive strands in the grid. The touch sensor circuitry may provide drive signals to the vertical (or horizontal) lines and may gather corresponding sense signals from the horizontal (or vertical) lines. Capacitive coupling between the drive and sense lines varies in the presence of a user&#39;s finger over a drive-line-to-sense-line intersection. As a result, the touch sensor circuitry in control circuitry  22  can process the drive and sense signals to determine which of the intersections of the conductive horizontal and vertical lines are being overlapped by a user&#39;s finger(s) or other external objects. Touch input that is detected this way (e.g., multitouch input corresponding to a pinch to zoom gesture, a multi-finger or single finger tap or swipe, or other touch input) may be used by item  10  to perform any suitable action. For example, in configurations in which item  10  has the ability to play media for a user, the touch input may be used to control media playback operations, in configuration in which item  10  has the ability to display images, displayed image content may be adjusted based on the touch input, in configurations in which item  10  includes or communicates with cellular telephone circuitry, touch input may direct item  10  to answer or place a telephone call, etc. 
     Fabric  12  may be formed inside item  10  or may be formed on the surface of item  10  (e.g., on an exterior wall, the surface of a housing, the surface of a strap or other fabric structure, etc.). In configurations in which conductive strands of material in fabric  12  are used in forming a grid of capacitive touch sensor electrodes, sensor performance may be enhanced by ensuring that fabric  12  is uncovered (or only thinly covered) with additional layers of material (e.g., additional fabric layers, plastic layers, etc.). In an uncovered state, a user&#39;s fingers can come into close proximity to the intersections between the conductive strands in a capacitive touch sensor grid, thereby enhancing signal-to-noise ratios. 
     Particularly in configurations in which fabric  12  forms an outer surface of some or all of item  10 , it may be desirable to visually hide conductive strands  20 C and  18 C. For example, it may be desirable to match the appearance of conductive strands  20 C and  18 C to insulating strands  20 I and  18 I, so that strands  20 C and  18 C are visually indistinct from strands  20 I and  18 I. In this way, fabric  12  may have a desired outward appearance even in the presence of conductive strands that are being used to gather touch sensor input for a fabric touch sensor or that are being used to route signals for other components. 
     With one illustrative arrangement, the appearance of insulating and conductive strands may be matched by coating the insulating and conductive strands with similarly or identically colored polymer coatings or other surface treatment, by coating metal wires with colored polymer to match the color of solid polymer fibers, etc. With another illustrative arrangement, conductive fibers may be embedded in the center of a bundle of insulating fibers. In this way, the outer insulating fibers that surround the interior conductive fibers may help shield the interior conductive fibers from view. 
       FIGS. 3, 4, and 5  are cross-sectional side views of illustrative fibers (sometimes referred to as monofilaments) that may be used in forming insulating and conductive yarns. 
     In the example of  FIG. 3 , fiber  26  is formed from a single material. In insulating fibers, the material may be a polymer, a natural insulating material such as cotton, flax, silk, or wool, or other dielectric. In conductive fibers, the material may be a conductive material such as metal (e.g., copper). 
     In the example of  FIG. 4 , fiber  26  has a core portion such as fiber core  26 - 1  and has an exterior coating layer such as coating  26 - 2 . In insulating fibers, core  26 - 1  and coating  26 - 2  may be polymers, natural materials, or other dielectric. For example, core  26 - 1  may be formed from a polymer that exhibits desired properties for use in fabric  12  such as strength and elasticity, whereas coating  26 - 2  may be a colored polymer that is used to impart fiber  26  with a desired color or other appearance. In conductive fibers, core  26 - 1  of  FIG. 4  may be a conductive material (e.g., copper) and exterior coating  26 - 2  may be a polymer (e.g., a colored polymer such as a white, gray, or black polymer or a polymer of other suitable colors such as red, green, blue, etc.). Conductive fibers may also be formed from polymer cores (i.e., core  26 - 1 ) coated with metal coatings (i.e., coating  26 - 2 ). 
     If desired, fiber  26  may be formed from three or more layers such as layers  26 - 1 ,  26 - 2 , and  26 - 3  of  FIG. 5 . In insulating fibers, layers  26 - 1 ,  26 - 2 , and  26 - 3  may be polymers. In conductive fibers, one or more of layers  26 - 1 ,  26 - 2 , and  26 - 3  may be formed from conductive materials such as metal and the remaining layer(s) may be formed from polymer (as examples). 
     Yarn may be formed from multiple fibers  26 , as illustrated by yarn  28  of  FIG. 6 . Fibers  26  for yarn  28  may be intertwined by spinning, braiding, or by otherwise intertwining fibers  26 . Insulating yarn  28  may be formed from a collection of insulating fibers  26 . Conductive yarn may be formed from fibers  26  that are all conductive or may be formed from both insulating and conductive fibers  26 . 
     In the example of  FIG. 7 , yarn  28  includes both insulating fibers  26 I and conductive fibers  26 C and is therefore conductive. Fibers  26 I and fibers  26 C may be spun together in a yarn spinning tool or may otherwise be intertwined to form yarn  28  (e.g., using braiding equipment, etc.). Fibers  26 C may be bare metal wire (e.g., copper wire) as illustrated by fiber  26  of  FIG. 3  or may have multiple layers of material. Because conductive fibers  26 C are located in the interior of yarn  28  of  FIG. 7 , conductive fibers  26 C are hidden from view. 
     Conductive yarns such as yarn  28  of  FIG. 7  may visually match the appearance of insulating yarns such as yarn  28  of  FIG. 6  that is formed only from insulating fibers  26 I (e.g., insulating fibers  26  in yarn  28  of  FIG. 6  may be formed from the same polymer that is used in forming the insulating fibers in conductive yarn  28  of  FIG. 7 ). This may make the conductive yarn visually indistinguishable from the insulating yarn. Fabric  12  that is formed using both the insulating and the conducting yarn will therefore appear as if it contains only insulating yarn. 
     As an example, woven fabric  12  may be formed in which the fabric has insulating warp and weft yarns with interspersed conductive warp and weft yarns as illustrated by insulating strands  20 I and  18 I of fabric  12  of  FIG. 2  and interspersed conductive strands  20 C and  18 C. In general, insulating strands in fabric  12  such as insulating strands  18 I and  20 I may be formed from one or more insulating fibers (monofilaments) such as insulating fibers  26  of  FIGS. 3, 4 , and  5  and/or may be formed from one or more insulating yarns  28 , each of which is formed from a set of two or more insulating fibers  26 . Likewise, conductive strands in fabric  12  such as conductive strands  18 C and  20 C may be formed from one or more conductive fibers (monofilaments) such as conductive fibers  26  of  FIGS. 3, 4, and 5  and/or may be formed from one or more conductive yarns  28  each of which includes at least some conductive fibers. Configurations in which the insulating strands of fabric  12  are insulating yarns and in which the conductive strands of fabric  12  are conductive yarns may sometimes be described herein as an example. 
     In arrangements in which fabric  12  includes yarns  28  with multiple fibers, each yarn  28  may contain any suitable number of fibers. As an example, each yarn  28  may contain 2-200 fibers (monofilaments such as monofilaments  26  of  FIGS. 3, 4, and 5 ), may contain 10-150 fibers, may contain 70-160 fibers, may contain more than 10 fibers, may contain 5-55 fibers, may contain more than 20 fibers, may contain more than 100 fibers, may contain fewer than 500 fibers, may contain fewer than 300 fibers, may contain fewer than 150 fibers, may contain 25-35 fibers, may contain fewer than 140 fibers, may contain 10-60 fibers, may contain 34 fibers, or may contain other suitable numbers of fibers. 
     Each fiber  26  may have a diameter of 8-100 microns, 2-500 microns, more than 5 microns, more than 10 microns, more than 20 microns, more than 40 microns, less than 200 microns, less than 150 microns, less than 100 microns, less than 50 microns, or any other suitable diameter. In configurations in which fibers  26  include coating layers, each coating may have a thickness of 1-40% of the diameter of the fiber, 1-15% of the diameter of the fiber, more than 0.2% of the diameter of the fiber, less than 5% of the diameter of the fiber, less than 35% of the diameter of the fiber, etc. 
     Fibers  26  and yarns  28  may have any suitable linear density. As an example, yarn  28  may be a 100 denier yarn, may be a 40-200 denier yarn, may be a 70-150 denier yarn, may be a 100 to 130 denier yarn, may be a 110 denier yarn, may have a linear density of more than 10 denier, more than 75 denier, less than 300 denier, less than 180 denier, 50-160 denier, or any other suitable value. 
     The percentage of conductive fibers in yarn  28  may be 1-10%, more than 2%, more than 10%, more than 50%, 90-100%, less than 70%, less than 15%, or any other suitable value. Yarn  28  may, for example, have 10-50 insulating fibers and 2-10 conducting fibers. With an illustrative arrangement, yarn  28  is 110 denier yarn having 31 insulating fibers (e.g., polymer and/or natural fibers) and 4 conductive fibers (e.g., bare copper wires). The fibers in this illustrative example may all have the same size (e.g., a diameter in the range of 8-100 microns) or may have multiple sizes. If desired, yarn  28  may contain copper wires or other conductive monofilaments intertwined with multifilament insulating or conductive threads or may contain both conducting and insulating multifilament threads. 
     Yarn  28  may be formed by intertwining fibers  26  using intertwining techniques such as braiding or spinning. Braided yarns may be stiffer than spun yarns. In some fabrics, spun yarn may provide a desired flexible characteristic. 
     Illustrative weaving equipment is shown in  FIG. 8 . Weaving equipment  220  may be used to form fabric  12 . The strands of material used in forming fabric  12  may be single-filament strands  26  (sometimes referred to as fibers) or may be multifilament yarns  28 . 
     As shown in  FIG. 8 , weaving equipment  220  includes a warp strand source such as warp strand source  240 . Source  240  may supply warp strands  20  from a warp beam or other strand dispensing structure. Source  240  may, for example, dispense warp strands  20  through rollers  260  and other mechanisms as drum  80  rotates about rotational axis  78  in direction  76 . 
     Warp strands  20  may be positioned using warp strand positioning equipment  74 . Equipment  74  may include heddles  36 . Heddles  36  may each include an eye  30  mounted on a wire or other support structure that extends between respective positioners  42  (or a positioner  42  and an associated spring or other tensioner). Positioners  42  may be motors (e.g., stepper motors) or other electromechanical actuators. Positioners  42  may be controlled by a controller during weaving operations so that warp strands  20  are placed in desired positions during weaving. In particular, control circuitry in weaving equipment  220  may supply control signals that move each heddle  36  by a desired amount up or down in directions  32 . By raising and lowering heddles  36  in various patterns in response to control signals from the control circuitry, different patterns of gaps (sheds)  66  between warp strands  20  may be created to adjust the characteristics of the fabric produced by equipment  220 . 
     Weft strands such as weft strand  18  may be inserted into shed  66  during weaving to form fabric  12 . Weft strand positioning equipment  62  may be used to place one or more weft strands  18  between the warp strands forming each shed  66 . Weft strand positioning equipment for equipment  220  may include one or more shuttles and/or may include shuttleless weft strand positioning equipment (e.g., needle weft strand positioning equipment, rapier weft strand positioning equipment, or other weft strand positioning equipment such as equipment based on projectiles, air or water jets, etc.). 
     After each pass of weft strand  18  is made through shed  66 , reed  48  may be moved in direction  50  by positioner  38  to push the weft strand that has just been inserted into the shed between respective warp strands  20  against previously woven fabric  12 , thereby ensuring that a satisfactorily tight weave is produced. Fabric  12  that has been woven in this way may be gathered on fabric collection equipment such as take-down roller  82 . Roller  82  may collect woven fabric  12  as roller  82  rotates in direction  86  about rotational axis  84 . Reed  48  and shuttle  62  and/or other weft strand positioning equipment may be controlled by the control circuitry that controls heddles  36 , so that warp strand position, weft strand positioning, and reed movement can be controlled in a coordinated fashion. 
     Positioners  42  may be used to control the vertical position of warp strands  20  when forming fabric  12 . As shown in  FIG. 8 , for example, heddle  36 - 2  may be placed above heddle  36 - 1 , so that warp strand  20 - 2  is placed above warp strand  20 - 1 . The ability to determine the heights of warp strands  20  within shed  66  during weaving may be used to help determine which warp strands interact with shuttle  62 , so that weaving equipment  220  can manipulate conductive and insulating strands within fabric  12 . This allows short circuits and open circuits to be selectively formed at various warp-weft strand intersections, allows electrical components to be coupled to the strands, allows conductive structures such as signal paths (e.g., electrodes, data lines, power paths, etc.) to be formed in fabric  12 , and allows other fabric structures to be formed. If desired, some of heddles  36  may contain eyes  30  that are mounted on a common wire. The use of independently adjustable heddles is merely illustrative. 
     In some applications, the conductive signal paths in fabric  12  may be several millimeters wide to achieve low resistance and to be able to provide power to an electronic device. In fabric  12  of  FIG. 9 , for example, fabric  12  has multiple conductive signal paths  52  including a power line such as power line  52 - 1 , a data path such as data path  52 - 2 , and a ground path such as ground path  52 - 3 . One or more of signal paths  52  may have be several millimeters wide. For example, power line  52 - 1  may have a width W between 70 and 80 millimeters, between 60 and 75 millimeters, between 50 and 100 millimeters, greater than 60 millimeters, or less than 60 millimeters. 
     In addition to having low resistance, electrical paths  52  in fabric  12  may need to be flexible and able to withstand bending of fabric  12 . In particular, fabric  12  may form part of an electronic device (e.g., electronic device  10  of  FIG. 1 ) that is configured to bend along bend axis  54  during normal use. For example, fabric  12  may be a cover for an electronic device that can also be used as a stand for the electronic device (e.g., a stand that can be used to prop the electronic device up for a user to view a display on the electronic device). In situations such as these, a user may bend fabric  12  along bend axis  54  to transition fabric  12  from a flat cover use to a bent stand use. It may therefore be desirable to form electrical paths  52  from conductive strands in fabric  12  so that electrical paths are flexible and able to withstand repetitive bending. 
     To form electrical paths with sufficiently low resistance, it may be desirable to group several conductive strands together in fabric  12 . For example, power line  52 - 1  may be formed from between 450 and 500 conductive strands, between 400 and 450 conductive strands, between 300 and 600 conductive strands, more than 500 strands, or less than 500 strands. 
     By grouping together conductive strands in fabric  12 , more short-circuiting between the conductive strands will occur to achieve an electrical path with low resistance.  FIGS. 10 and 11  illustrate how conductive strands in fabric  12  may be packed more tightly together than insulating strands in fabric  12  to achieve more short-circuiting between conductive strands. In the example of  FIG. 10 , weft strands  18  are conductive and warp strands  20  are insulating. In the example of  FIG. 11 , warp strands  20  are conductive and weft strands  18  are insulating. 
     As shown in  FIG. 10 , weft strands  18  are packed more tightly than warp strands  20 . In particular, the number of weft strands  18  in distance D may be greater than the number of warp strands  20  in the same distance D. The number of weft strands in an inch of fabric is sometimes referred to as the number of picks per inch (PPI). The number of warp strands in an inch of fabric is sometimes referred to as the number of ends per inch (EPI). In the example of  FIG. 10 , weft strands  18  are conductive and warp strands  20  are insulating, so the number of picks per inch in fabric  12  may be greater than the number of ends per inch in fabric  12 . For example, the picks per inch of fabric  12  may be 200 or greater, while the ends per inch of fabric  12  may be 200 or less. If desired, the number of warp strands on the beam may be 12,000 or less to reduce the space between conductive weft strands  18 . 
     As shown in  FIG. 11 , weft strands  18  are insulating and warp strands  20  are conductive, so warp strands  20  are packed more tightly than weft strands  18 . In particular, the number of warp strands  20  in distance D may be greater than the number of weft strands  18  in the same distance D. In other words, the number of ends per inch may be greater than the number of picks per inch when warp strands  20  are used as the conductive strands in fabric  12 . 
       FIG. 12  illustrates another principle of fabric construction that may maximize the short-circuiting between adjacent conductive strands in fabric  12 . As shown in  FIG. 12 , fabric  12  may include conductive strands  28 C and insulating strands  28 I. Conductive strands  28 C may be weft strands and insulating strands  28 I may be warp strands, or conductive strands  28 C may be warp strands and insulating strands  28 I may be weft strands. Fabrics such as fabric  12  may have one or more floats such as float  56 . A weft float occurs when a weft strand passes over two or more warp strands. A warp float occurs when a warp strand passes over two or more warp strands. In the example of  FIG. 12 , insulating strand  28 I floats over three conductive strands  28 C, helping to pinch conductive strands  28 C together. In arrangements of the type shown in  FIG. 10  where weft strands  18  are conductive, fabric  12  may be woven in a pattern that includes warp floats that pass over two, three, or more than three weft strands. In arrangements of the type shown in  FIG. 11  where warp strands  20  are conductive, fabric  12  may be woven in a pattern that includes weft floats that pass over two, three, or more than three warp strands. 
       FIGS. 13-24  show different fabric constructions that may provide satisfactory short circuiting between conductive strands in fabric  12 . The weaving diagrams of  FIGS. 13, 15, 17, 19, 21, and 23  show how a loom may be instructed to operate. The shaded squares show when a warp strand is on top (e.g., when one of warp strands  20  of  FIG. 8  is raised up above shed  66 ), and the non-shaded squares show when a weft strand is on top (e.g., when one of warp strands  20  of  FIG. 18  is lowered below shed  66 ). Each weaving diagram is followed by an illustration of the fabric that may be produced with that weaving diagram. 
     Weaving diagram  90  of  FIG. 13  illustrates a two up and three down twill pattern in which weft strands  18  are conductive and warp strands  20  are insulating. With this type of pattern, for every five warp strands  20  in shed  66 , the first and third warp strands  20  are up and the second, fourth, and fifth warp strands  20  are down. This type of weaving produces a fabric of the type shown in  FIG. 14 . As shown in  FIG. 14 , the fabric construction of  FIG. 13  results in regions such as regions  92  in which three conductive weft strands  18  are in contact with one another (and not separated by insulating warp strands  20 ). 
     Weaving diagram  90  of  FIG. 15  illustrates a two up and three down twill pattern in which warp strands  20  are conductive and weft strands  18  are insulating. With this type of pattern, for every five warp strands  20  in shed  66 , the second and third warp strands  20  are up and the first, fourth, and fifth warp strands  20  are down. This type of weaving produces a fabric of the type shown in  FIG. 16 . As shown in  FIG. 16 , the fabric construction of  FIG. 15  results in regions such as regions  94  in which three conductive warp strands  20  are in contact with one another (and not separated by insulating weft strands  18 ). Since  FIG. 15  is a top view of fabric  12  and shows which yarns are on top, regions  94  are formed from groups of “down” warp strands  20  and are located on the opposing side of fabric  12  below weft strands  18 . 
     Weaving diagram  90  of  FIG. 17  illustrates a two up and three down modified twill pattern in which weft strands  18  are conductive and warp strands  20  are insulating. With this type of pattern, for every five warp strands  20  in shed  66 , the first and second warp strands  20  are up and the third, fourth, and fifth warp strands  20  are down. This type of weaving produces a fabric of the type shown in  FIG. 18 . As shown in  FIG. 18 , the fabric construction of  FIG. 17  results in regions such as regions  96  in which four conductive weft strands  18  are in contact with one another (and not separated by insulating warp strands  18 ). 
     Weaving diagram  90  of  FIG. 19  illustrates a two up and three down modified twill pattern in which warp strands  20  are conductive and weft strands  18  are insulating. With this type of pattern, for every five warp strands  20  in shed  66 , the first, second, and third warp strands  20  are down and the fourth and fifth warp strands  20  are up. This type of weaving produces a fabric of the type shown in  FIG. 20 . As shown in  FIG. 20 , the fabric construction of  FIG. 19  results in regions such as regions  98  in which four conductive warp strands  20  are in contact with one another (and not separated by insulating weft strands  18 ). Since  FIG. 20  is a top view of fabric  12  and shows which yarns are on top, regions  98  are formed from groups of “down” warp strands  20  and are located on the opposing side of fabric  12  below weft strands  18 . 
     Weaving diagram  90  of  FIG. 21  illustrates a three up and two down twill pattern in which weft strands  18  are conductive and warp strands  20  are insulating. With this type of pattern, for every five warp strands  20  in shed  66 , the first, second, and fourth warp strands  20  are up and the third and fifth warp strands  20  are down. This type of weaving produces a fabric of the type shown in  FIG. 22 . As shown in  FIG. 22 , the fabric construction of  FIG. 21  results in regions such as regions  120  in which multiple groups of two conductive weft strands  18  are in contact with one another along a diagonal. In this way, a weft strand in location  124  may be electrically connected to a weft strand in location  126 , even though there are two strands in between. Since  FIG. 22  is a top view of fabric  12  and shows which yarns are on top, regions  120  are formed from groups of weft strands  18  that are located on the opposing side of fabric  12  below warp strands  20 . 
     Weaving diagram  90  of  FIG. 23  illustrates a three up and two down twill pattern in which warp strands  20  are conductive and weft strands  18  are insulating. With this type of pattern, for every five warp strands  20  in shed  66 , the second, third, and fifth warp strands  20  are up and the first and fourth warp strands  20  are down. This type of weaving produces a fabric of the type shown in  FIG. 24 . As shown in  FIG. 24 , the fabric construction of  FIG. 23  results in regions such as regions  122  in which multiple groups of two conductive warp strands  20  are in contact with one another along a diagonal. In this way, a warp strand in location  128  may be electrically connected to a weft strand in location  130 , even though there are two strands in between. 
     The fabric constructions of  FIGS. 13-24  are merely illustrative. If desired, other fabric constructions may be used to produce fabric in which multiple conductive strands are shorted together to form a conductive signal path with low electrical resistance. 
     The foregoing is merely illustrative and various modifications can be made by those skilled in the art without departing from the scope and spirit of the described embodiments. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20170815
Publication Date: 20190903
Grant Date: 20190903
Priority Date: 20160920
Inventors: MAYER, KIRK M.
HAMADA, Yohji
PODHAJNY, DANIEL A.
SUNSHINE, Daniel D.
Assignee: APPLE INC
CPC Classifications: [{"code": "D03D13/004", "inventive": true, "first": false, "tree": "[]"}, {"code": "D10B2401/16", "inventive": false, "first": false, "tree": "[]"}, {"code": "D03D1/0088", "inventive": true, "first": false, "tree": "[]"}, {"code": "D03D1/0088", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01B5/002", "inventive": true, "first": false, "tree": "[]"}, {"code": "D02G3/441", "inventive": true, "first": true, "tree": "[]"}, {"code": "D03D15/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "D03D15/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "D03D15/50", "inventive": true, "first": false, "tree": "[]"}, {"code": "D03D15/25", "inventive": true, "first": false, "tree": "[]"}, {"code": "D03D15/50", "inventive": true, "first": false, "tree": "[]"}, {"code": "D03D15/25", "inventive": true, "first": false, "tree": "[]"}, {"code": "D03D15/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01B5/002", "inventive": true, "first": false, "tree": "[]"}, {"code": "D03D1/0088", "inventive": true, "first": false, "tree": "[]"}, {"code": "D02G3/441", "inventive": true, "first": true, "tree": "[]"}, {"code": "D02G3/441", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 67770133