PATENT DOCUMENT

Publication Number: US-10724158-B2
Application Number: US-201615549110-A
Country: US
Kind Code: B2

Title: Woven fabric with conductive paths

Abstract:
Weaving equipment may include warp strand positioning equipment that positions warp strands and weft strand positioning equipment that inserts weft strands among the warp strands to form fabric. The fabric may include insulating strands and conductive strands. Conductive strands may run orthogonal to each other and may cross at open circuit and short circuit intersections. The fabric may be formed using pairs of interwoven warp and weft strands. Conductive warp and weft strands may be interposed within the pairs of strands. The fabric may be a single layer fabric or may contain two or more layers. Stacked warp strands may be formed between pairs of adjacent insulating warp strands. The stacked warp strands may include insulating and conductive strands. Touch sensors and other components may include conductive structures that are formed from the conductive strands in the fabric.

Claims:
What is claimed is: 
     
       1. A fabric, comprising:
 weft strands that run along a first dimension, wherein the weft strands include a conductive weft strand and an insulating weft strand that is adjacent to the conductive weft strand; and 
 interwoven warp strands that run along a second dimension that is orthogonal to the first dimension, wherein the warp strands include:
 first and second insulating strands that are interwoven with the weft strands; and 
 stacked strands that form a stack extending in a third dimension that is orthogonal to the first and second dimensions, wherein the stacked strands are interposed between the first and second insulating strands such that the first and second insulating strands hold the stacked strands in the stack, wherein the fabric has at least one portion in which the stacked strands include a conductive stacked strand sandwiched between two insulating stacked strands to form an open circuit connection at which the conductive weft strand and the conductive stacked strand overlap and are isolated from each other by one of the two insulating stacked strands, and wherein the stacked strands and the first and second insulating strands are located between the conductive weft strand and the insulating weft strand. 
 
 
     
     
       2. The fabric defined in  claim 1  further comprising first and second fabric layers, wherein the weft and warp strands form part of the first fabric layer. 
     
     
       3. The fabric defined in  claim 1  wherein the stacked strands include an additional conductive stacked strand and two additional insulating stacked strands and wherein the fabric has opposing first and second surfaces and has at least one additional portion in which the additional conductive stacked strand is positioned above the two additional insulating stacked strands and is exposed at the first surface. 
     
     
       4. The fabric defined in  claim 3  wherein at least one of the weft strands is an additional conductive weft strand. 
     
     
       5. The fabric defined in  claim 4  wherein the additional conductive weft strand and the additional conductive stacked strand intersect at a short circuit intersection in which the additional conductive weft strand and the additional conductive stacked strand contact each other and are shorted to each other. 
     
     
       6. The fabric defined in  claim 5  further comprising first and second fabric layers, wherein the weft and warp strands form part of the first fabric layer. 
     
     
       7. The fabric defined in  claim 1  wherein the conductive stacked strand comprises a bare metal wire. 
     
     
       8. The fabric defined in  claim 1  wherein the conductive stacked strand forms at least part of a capacitive touch sensor electrode. 
     
     
       9. A fabric comprising:
 insulating weft strands interwoven with insulating warp strands, wherein the insulating weft strands extend along a first dimension and the insulating warp strands extend along a second dimension that is orthogonal to the first dimension; 
 a conductive weft strand that extends along the first dimension and that is interposed between two of the insulating weft strands; and 
 stacked warp strands that extend along the second dimension and that include a conductive stacked strand interposed between two insulating stacked strands, wherein the conductive weft strand and the conductive stacked strand cross each other at an open circuit intersection in which the conductive weft strand and the conductive stacked strand do not contact each other, and wherein the conductive weft strand and the conductive stacked strand are held apart at the open circuit intersection by one of the insulating stacked strands, wherein the insulating warp strands include first and second insulating warp strands that hold the stacked strands in a stack that extends in a third dimension that is orthogonal to the first and second dimensions, and wherein the stack and the first and second insulating warp strands are located between the conductive weft strand and one of the two insulating weft strands. 
 
     
     
       10. The fabric defined in  claim 9  wherein the conductive weft strand and the conductive stacked strand comprise bare metal wire. 
     
     
       11. The fabric defined in  claim 9  further comprising:
 an additional conductive weft strand that extends along the first dimension and that is interposed between two additional ones of the insulating weft strands, wherein the stacked strands include an additional conductive stacked strand that extends along the second dimension and that is interposed between two additional insulating stacked strands, wherein the additional conductive weft strand and the additional conductive stacked strand cross each other at a short circuit intersection in which the additional conductive weft strand and the additional conductive stacked strand contact each other and are electrically shorted to each other. 
 
     
     
       12. The fabric defined in  claim 11  wherein the additional conductive weft strand and the additional conductive stacked strand comprise bare metal wire. 
     
     
       13. The fabric defined in  claim 9  wherein at least one of the conductive weft strand and the conductive stacked strand forms at least part of a capacitive touch sensor electrode. 
     
     
       14. A fabric, comprising:
 insulating warp strands that extend along a first dimension; 
 insulating weft strands that extend along a second dimension that is orthogonal to the first dimension, wherein the insulating warp strands and the insulating weft strands are interwoven; 
 a conductive warp strand that extends along the first dimension and that lies between two of the insulating warp strands; 
 a conductive weft strand that extends along the second dimension and that lies between two of the insulating weft strands, wherein the insulating warp strands and the insulating weft strands are interwoven in a basket weave; and 
 additional insulating warp strands that hold the conductive warp strand in a stack with at least two of the insulating warp strands, wherein the stack extends in a third dimension that is orthogonal to the first and second dimensions, wherein the conductive warp and weft strands overlap at an open circuit intersection and are held apart by at least one of the two insulating warp strands in the stack, and wherein the stack and the additional insulating warp strands are located between the conductive weft strand and one of the two insulating weft strands. 
 
     
     
       15. The fabric defined in  claim 14  further comprising an additional conductive warp strand and an additional conductive weft strand that intersect at a short circuit intersection in which the additional conductive warp strand and the additional conductive weft strand contact each other.

Description:
This application claims priority to patent application No. 62/116,283, filed on Feb. 13, 2015, which is hereby incorporated by reference herein in its entirety. 
    
    
     BACKGROUND 
     This relates generally to weaving and, more particularly, to woven fabric that contains conductive paths. 
     It may be desirable to form electrical devices, enclosures, and other items from fabric. The fabric may contain strands of insulating material and strands of conductive material. In some situations, it may be desirable to form signal paths or other conductive structures from the conductive strands. Challenges may arise when forming conductive structures from conductive strands in a fabric. If care is not taken, a conductive strand in a signal path will be inadvertently shorted to conductive structures that are not intended to form part of the signal path or conductive strands in a path will be unintentionally isolated from each other. Unintended shorts and open circuits and other defects such as these such as these may prevent an item from functioning properly. 
     It would therefore be desirable to be able to provide improved techniques for forming conductive structures in fabric-based items. 
     SUMMARY 
     Weaving equipment may include warp strand positioning equipment that positions warp strands and weft strand positioning equipment that inserts weft strands among the warp strands to form fabric. The fabric may include insulating strands and conductive strands. 
     Conductive strands may run orthogonal to each other and may cross at open circuit and short circuit intersections. Intersections may be configured as open circuits or short circuits to form desired conductive paths through the fabric. The paths may be used as signal routing paths, as portions of capacitive touch sensor electrodes, as portions of resistive sensors, or as portions of any other conductive structures for a fabric-based item. 
     The fabric may be formed using pairs of warp strands that have been interwoven with pairs of weft strands. In this type of fabric, conductive warp and weft strands may be interposed within the pairs of strands and selectively coupled or isolated from each other at intersections within the fabric. 
     The fabric may be a single layer fabric or may contain two or more layers. In some arrangements, stacked warp strands may be formed between pairs of adjacent insulating warp strands. The stacked warp strands may include insulating and conductive strands. The conductive strands in the stacked strands may be selectively sandwiched between opposing insulating strands or moved to the top or the bottom of the stack so that a conductive strand makes contact with an orthogonal conductive strand or is exposed on a desired fabric surface. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of an illustrative strand-based item in accordance with an embodiment. 
         FIG. 2  is a side view of illustrative weaving equipment that may be used to form fabric in accordance with an embodiment. 
         FIGS. 3, 4, and 5  are side views of illustrative fabric in which conductive and insulating strands are positioned at different locations in the fabric in accordance with an embodiment. 
         FIGS. 6 and 7  show healds in a weaving system in accordance with an embodiment. 
         FIG. 8  shows fabric having strand stacks with two strands being formed using the heald configurations of  FIGS. 6 and 7  in accordance with an embodiment. 
         FIGS. 9 and 10  show healds in a weaving system, and  FIG. 11  shows a fabric formed using the healds of  FIGS. 9 and 10  in accordance with another embodiment. 
         FIGS. 12 and 13  are cross-sectional side views of illustrative two layer fabrics in accordance with an embodiment. 
         FIGS. 14 and 15  are cross-sectional side views of illustrative fabric with different stacked strand patterns in accordance with an embodiment. 
         FIGS. 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, and 27  show process steps involved in weaving fabric of the type shown in  FIGS. 14 and 15  in accordance with an embodiment. 
         FIG. 28  is a graph in which warp strand position has been plotted as a function of time for several different types of warp strands in a fabric that is being woven in accordance with an embodiment. 
         FIG. 29  is a diagram of an illustrative open circuit intersection between conductive strands in accordance with an embodiment. 
         FIG. 30  is a diagram of an illustrative short circuit intersection between conductive strands in accordance with an embodiment. 
         FIG. 31  is a diagram of a portion of a fabric in which a conductive path has been configured to form an inductor in accordance with an embodiment. 
         FIG. 32  is perspective view of illustrative fabric formed from interwoven pairs of insulating warp and weft strands and conductive strands that run along the centers of the warp and weft strand pairs in accordance with an embodiment. 
         FIG. 33  is a front view of a portion of the illustrative fabric of  FIG. 32  at an illustrative open circuit intersection in accordance with an embodiment. 
         FIG. 34  is a rear view of a portion of the illustrative fabric of  FIG. 32  at an illustrative open circuit intersection in accordance with an embodiment. 
         FIG. 35  is a cross-sectional side view of the open circuit intersection of  FIG. 33  in accordance with an embodiment. 
         FIG. 36  is a cross-sectional side view of the closed circuit intersection of  FIG. 34  in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Conductive strands of material and insulating strands of material may be used in forming fabric with conductive paths. The conductive paths may be used in forming signal paths (e.g., signal busses, power lines, etc.), may be used in forming part of a capacitive touch sensor electrode, a resistive touch sensor electrode, or other input-output device, or may be used in forming other patterned conductive structures. The conductive structures may be used in carrying power signals, digital signals, analog signals, sensor signals, control signals, data, input signals, output signals, or other suitable electrical signals. 
     The fabric containing these conductive structures may be used in forming a fabric-based item such as illustrative fabric-based item  10  of  FIG. 1 . Item  10  may be an electronic device or an accessory for an electronic device such as 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 wrist-watch 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 fabric-based 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, 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, etc.), or may be any other suitable fabric-based item. 
     Strands in item  10  may form all or part of a housing wall for an electronic device, may form internal structures in an electronic device, or may form other strand-based structures. Item  10  may be soft (e.g., item  10  may have a fabric surface that yields to a light touch), may have a rigid feel (e.g., the surface of item  10  may be formed from a stiff fabric), may be coarse, may be smooth, may have ribs or other patterned textures, and/or may be formed as part of a device that has portions formed from non-fabric structures of plastic, metal, glass, crystalline materials, ceramics, or other materials. 
     Item  10  may include intertwined strands  12 . The strands may be intertwined using strand intertwining equipment such as weaving equipment, knitting equipment, or braiding equipment. Intertwined strands  12  may, for example, form woven fabric. 
     Strands  12  may be single-filament strands (sometimes referred to as fibers) or may be threads, yarns, or other strands that have been formed by intertwining multiple filaments of material together. Strands may be formed from polymer, metal, glass, graphite, ceramic, natural strands such as cotton or bamboo, or other organic and/or inorganic materials and combinations of these materials. Conductive coatings such as metal coatings may be formed on non-conductive strands (e.g., plastic cores) to make them conductive. Reflective coatings such as metal coatings may be applied to strands to make them reflective. Strands  12  may also be formed from single-filament metal wire (e.g., bare metal wire), multifilament wire, or combinations of different materials. Strands may be insulating or conductive. 
     Strands  12  may be conductive along their entire length or may have conductive segments. Strands  12  may have metal portions that are selectively exposed by locally removing insulation (e.g., to form connections with other conductive strand portions). Strands  12  may also be formed by selectively adding a conductive layer to a portion of a non-conductive strand.). Threads and other multifilament yarns that have been formed from intertwined filaments may contain mixtures of conductive strands and insulating strands (e.g., metal strands or metal coated strands with or without exterior insulating layers may be used in combination with solid plastic strands or natural strands that are insulating). 
     Conductive strands (complete conductive strands and/or conductive strand segments) that cross other conductive strands may be shorted to each other to form a portion of a signal path. Electrical connections of this type may be formed by virtue contacting a first conductive strand with a second conductive strand. 
     Item  10  may include additional mechanical structures  14  such as polymer binder to hold strands  12  together, support structures such as frame members, housing structures (e.g., an electronic device housing), and other mechanical structures. 
     To enhance mechanical robustness and electrical conductivity at strand-to-strand connections, additional structures and materials (e.g., solder, crimped metal connections, welds, conductive adhesive, non-conductive adhesive, fasteners, etc.) may be used to help form strand-to-strand connections at strand intersections where connections are desired. Insulating material can be interposed between intersecting conductive strands at locations in which it is not desired to form a strand-to-strand connection. The insulating material may be plastic or other dielectric, may include an insulating strand or a conductive strand with an insulating coating, etc. 
     Circuitry  16  may be included in item  10 . Circuitry  16  may include components that are coupled to strands  12 , components that are housed within an enclosure formed by strands  12 , components that are attached to strands  12  using welds, solder joints, adhesive bonds (e.g., conductive adhesive bonds), crimped connections, or other electrical and/or mechanical bonds. Circuitry  16  may include metal structures for carrying current, integrated circuits, discrete electrical components such as resistors, capacitors, and inductors, switches, connectors, light-emitting components such as light-emitting diodes, audio components such as microphones and speakers, vibrators, solenoids, piezoelectric devices, and other electromechanical devices, connectors, microelectromechanical systems (MEMs) devices, pressure sensors, light detectors, proximity sensors, force sensors, moisture sensors, temperature sensors, accelerometers, gyroscopes, compasses, magnetic sensors, touch sensors, and other sensors, components that form displays, touch sensors arrays (e.g., arrays of capacitive touch sensor electrodes to form a touch sensor that detects touch events in two dimensions), and other input-output devices. Circuitry  16  may also include control circuitry such as non-volatile and volatile memory, microprocessors, application-specific integrated circuits, system-on-chip devices, baseband processors, wired and wireless communications circuitry, and other integrated circuits. 
     Item  10  may interact with electronic equipment or other additional items  18 . Items  18  may be attached to item  10  or item  10  and item  18  may be separate items that are configured to operate with each other (e.g., when one item is a case and the other is a device that fits within the case, etc.). Circuitry  16  may include antennas and other structures for supporting wireless communications with item  18 . Item  18  may also interact with item  10  using a wired communications link or other connection that allows information to be exchanged. 
     In some situations, item  18  may be an electronic device such as a cellular telephone, computer, or other portable electronic device and item  10  may form a case or other structure that receives the electronic device in a pocket, an interior cavity, or other portion of item  10 . In other situations, item  18  may be a wrist-watch device or other electronic device and item  10  may be a strap or other fabric-based item that is attached to item  18 . In still other situations, item  10  may be an electronic device, strands  12  may be used in forming the electronic device, and additional items  18  may include accessories or other devices that interact with item  10 . Signal paths formed from conductive strands may be used to route signals in item  10  and/or item(s)  18 . 
     The strands that make up item  10  may be intertwined using any suitable strand intertwining equipment. With one suitable arrangement, which may sometimes be described herein as an example, strands  12  may be woven together to form a woven fabric. The fabric may have a plain weave, a satin weave, a twill weave, or variations of these weaves, may be a three-dimensional woven fabric, or may be other suitable fabric. 
     Illustrative weaving equipment for forming woven fabric for items such as item  10  of  FIG. 1  is shown in  FIG. 2 . During weaving, fabric may be formed using strands such as strands  12  of  FIG. 1 . The strands may be single filaments of material or may be threads, yarns, or other multifilament strands that have been formed by intertwining multiple single-filament strands. Strands may be formed from insulating materials, conductive materials, and combinations of insulating and conductive materials. The strands that are used include warp strands  28  and weft strands  64 . 
     As shown in  FIG. 2 , weaving equipment  22  includes a warp strand source such as warp strand source  24 . Source  24  may supply warp strands  28  from a warp beam or other strand dispensing structure. Source  24  may, for example, dispense warp strands  28  through rollers  26  and other mechanisms as drum  80  rotates about rotational axis  78  in direction  76 . 
     Warp strands  28  may be positioned using warp strand positioning equipment  74 . Equipment  74  may include healds (heddles)  36 . Healds  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  28  are placed in desired positions in the fabric being woven. In particular, control circuitry in weaving equipment  22  may supply control signals that move each heald  36  by a desired amount (e.g., up or down in directions  32 ). By raising and lowering healds  36  in various patterns in response to control signals from the control circuitry, different patterns of gaps (sheds)  66  between warp strands  28  may be created and warp strands  28  can be placed at different vertical positions within fabric  60 . 
     Weft strands such as weft strand  64  may be inserted into shed  66  during weaving to form fabric  60 . Weft strand positioning equipment  62  may be used to place one or more weft strands  64  between the warp strands forming each shed  66 . Weft strand positioning equipment  62  may include one or more shuttles 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  64  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  28  against previously woven fabric  60 , thereby ensuring that a satisfactorily tight weave is produced. Fabric  60  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  60  as roller  82  rotates in direction  86  about rotational axis  84 . Reed  48  and weft strand positioning equipment  62  may be controlled by the control circuitry that controls healds  36 , so that warp strand position, weft strand positioning, and reed movement can be controlled in a coordinated fashion. 
     To control the vertical position of warp strands  28  within fabric  60 , some of healds  36  such as illustrative healds  36 - 1  and  36 - 2  may be aligned along dimension X. In this configuration, the warp strands that are dispensed from these healds will be dispensed into the same warp strand position in fabric  60 . When the eye in heald  36 - 1  is raised above the eye in heald  36 - 2 , warp strand  28 - 1  will be incorporated into fabric  60  above warp strand  28 - 2  (i.e., strands  28 - 1  and  28 - 2  will be aligned with respect to axis X, which extends into the page in the example of  FIG. 2 , and strand  28 - 1  will lie on top of strand  28 - 2 ). Similarly, when heald  36 - 2  is raised above heald  36 - 1 , as shown in  FIG. 2 , warp strand  28 - 2  will be incorporated into fabric  60  above warp strand  28 - 1 . The ability to determine which warp strands are located on or near the top of fabric  60  and which strands are located on or near the bottom of fabric  60  allows conductive and insulating strands to be manipulated within fabric  60  so that short circuits and open circuits are selectively formed at various warp-weft strand intersections. This allows conductive structures such as signal paths (e.g., electrodes, data lines, power paths, etc.) to be formed in fabric  60  from a desired pattern of coupled horizontal and vertical conductive strand segments. 
     Some or all of healds  36  may be independently positioned and/or some of healds  36  may contain eyes  30  that are mounted on a common wire. In configurations for weaving equipment  22  in which eyes  30  are mounted on a common wire, the warp strands dispensed through the eyes will be aligned with respect to each other (i.e., their positions along dimension X of  FIG. 2  will be the same) and a movable needle or other controllable strand positioning member may be used to manipulate the upper and lower warp threads to determine which warp thread is located above the other. The use of independently adjustable healds  36  (including some independently adjustable healds  36  that are laterally aligned across warp strands  28  such as healds  36 - 1  and  36 - 2 ) is merely illustrative. Any suitable technique for determining the order in which warp threads  28  are stacked on top of each other within fabric  20  at a given warp strand position may be used, if desired. 
       FIGS. 3, 4, and 5  illustrate how warp strand positioning techniques may be used in fabricating fabric  60  with insulating and conducting strands  28 . In the examples of  FIGS. 3, 4, and 5 , warp strands  28  have been woven with weft strands  64  to form fabric  60 . Warp strands  28  include conductive strands such as conductive strand  28 C and insulating strands such as insulating strand  28 I. In the example of  FIG. 3 , warp strand  28 I has been positioned above warp strand  28 C, so the upper surface of fabric  60  is insulating and the lower surface of fabric  60 . In the example of  FIG. 4 , equipment  22  has been used to stack warp strand  28 I below warp strand  28 C, so the upper surface of fabric  60  is conductive and the lower surface of fabric  60  is insulating. If desired, fabric  60  may have a surface that is insulating in some areas and conductive in others. In the example of  FIG. 5 , the upper (front) surface of fabric  60  in area  90  is conductive, because conductive strand  28 C is located above insulating strand  28 I in area  90 , whereas the upper surface of fabric  60  is insulating in area  92 , because strand  28 I is located above strand  28 C in area  92 . 
     Warp strands  28  may be stacked vertically in different patterns by controlling healds  36 - 1  and  36 - 2 . Consider, as an example, the heald positions of  FIGS. 6 and 7 . When healds  36 - 1  and  36 - 2  are positioned as shown in  FIG. 6 , strand  28 I will be positioned above strand  28 C. When healds  36 - 1  and  36 - 2  are positioned as shown in  FIG. 7 , strand  28 C will be positioned above strand  28 I. 
     In fabric  60  of  FIG. 8 , healds  36 - 1  and  36 - 2  were positioned in the configuration of  FIG. 6  when forming fabric area  94  and were positioned in the configuration of  FIG. 7  when forming fabric area  96 . To help ensure that warp strands  28 I and  28 C stack vertically on top of each other as shown in  FIG. 8 , fabric  60  may be provided with laterally supporting warp strands  28 W (sometimes referred to as wall warp strands or guide warp strands). Wall warp strands  28 W may be insulating strands. Wall warp strands  28 W may flank centrally located and vertically stacked strands  28 I and  28 C on the left and right, thereby preventing strands  28 I and  28 C from deviating to the left or right along axis X and therefore becoming unstacked as fabric  60  is formed. In the illustrative configuration of  FIG. 8 , there is a single wall strand  28 W on the left and on the right of each set of stacked warp strands, but more than one wall strand may be provided on each side of the warp strand stack if desired. Wall strands  28 W may be larger than the central stacked warp strands (as an example). 
     There are only two stacked warp strands between an opposing pair of upper and lower weft strands  64  in fabric  60  of  FIG. 8 , but there may be three or more stacked warp strands in the lateral gap  100  between opposing wall strands  28 W. For example, portion  102  of fabric  60  of  FIG. 11  may be formed when the healds that are dispensing warp strands into gap  100  between wall strands  28 W in portion  102  are oriented as shown by illustrative healds  36  of  FIG. 9 . Other portions such as portion  104  of fabric  60  of  FIG. 11  may be formed when the healds that are dispensing warp strands into gap  100  between wall strands  28 W in portion  104  are oriented as shown by illustrative healds  36  of  FIG. 10 . 
     In portion  102 , conductive strand  28 C is insulated above and below by insulating strands  28 I. In portion  104 , conductive strand  28 C is exposed on the upper surface of fabric  60  (e.g., to form a touch sensor or other electrode, etc.) and may, if desired, contact an overlapping conductive weft strand. 
     If desired, weft strands  64  and wall strands  28 W of  FIGS. 8 and 11  may be insulating. One or more of strands  64  and  28 W may be conducting to help form a signal path or other conductive structure in fabric  60 . As one example, the warp strand that touches conductive upper warp strand  28 C in region  104  may be conductive so that an electrical warp-to-weft connection is formed with upper warp strand  28 C. 
     Fabric  60  may have two or more layers. In the illustrative configurations of  FIGS. 12 and 13 , fabric  60  has a two layer configuration including an upper layer such as layer  60 T and a lower layer such as layer  60 B. Wall strands  28 W may be insulating. Insulating warp strands  28 I and conductive warp strands  28 C may be stacked in various patterns within the gap formed between adjacent wall strands  28 W. The weft strands in fabric  60  may include insulating weft strands  64 I and conductive weft strands  64 C. 
     Using equipment  22 , fabric  60  may be formed that has desired warp-to-weft electrical connections at the intersections between conductive warp and weft strands. As shown in  FIG. 12 , for example, conductive warp strands  28 C may be brought into contact with conductive weft strand  64 C in regions such as regions  106  and  110 , so that warp-to-weft connections (short circuits) are formed. Insulating warp strands  28 I may be interposed between conductive warp strands  28 C and conductive weft strand  64 C in regions such as regions  108  and  112 , so that the warp and weft strands are electrically isolated from each other at the intersections of the conductive warp and weft strands in these regions (i.e., open circuits are formed). 
     Similarly, in the example of  FIG. 13 , warp strands  28 C may be isolated from weft strand  64 C in regions  114 ,  116 , and  120 , whereas the warp strands  28 C in region  118  may be electrically shorted to weft strand  64 C. 
     During weaving, equipment  22  can modify fabric  60  so that different areas of the fabric have different constructions (e.g., different patterns of warp strand stacks) and therefore have desired properties in these areas. 
     The process of changing the positions of warp strands  28  within the warp strand stacks between wall strands  28 W to selectively alter the configuration of fabric  60  in different regions of fabric  60  is illustrated in connection with  FIGS. 14-27 .  FIG. 14  shows two regions of an illustrative fabric at the beginning of a pick in which the orientation of the stacked warp strands is being adjusted and  FIG. 15  shows the same two regions at the end of the pick.  FIGS. 16-27  show the movement of the strands at various different times during the pick. 
     As shown in  FIG. 14 , conductive warp strand  28 C is initially sandwiched between upper and lower insulating warp strands  28 I in region  122 , whereas conductive warp strand  28 C is exposed at the top of the warp strand stack in region  124 . At the completion of the pick, conductive warp strand  28 C in region  122  has been moved to the top of the stack and conductive warp strand  28 C has been moved to an insulated position in the center of the stack in region  124 . 
     An illustrative set of steps for accomplishing this type of warp strand movement by adjustment of healds  36  in equipment  22  is shown in  FIGS. 16-27 . 
     Initially, as shown in  FIG. 16 , wall strands  28 W, warp strands  28 I, and warp strand  28 C in region  122  are moved down and wall strands  28 W, warp strands  28 I, and warp strand  28 C in region  124  are moved up. 
     A weft strand such as weft strand  64 A may then be introduced along direction X using weft strand positioning equipment  64 .  FIG. 17  shows strand  64 A as strand  64 A is first being introduced.  FIG. 18  shows stand  64 A after strand  64 A has crossed all warp strands  28 . Strand  64 A may be insulating or conductive. 
       FIGS. 19, 20, and 21  show how reed  48  may be used to push strand  64 A into place.  FIG. 19  shows reed  48  in its initial position, which is away from strand  64 A.  FIG. 20  shows reed  48  when reed  48  is pushing strand  64 A against fabric  60 .  FIG. 21  shows reed  48  after reed  48  has been pulled back after finishing the process of pushing strand  64 A against fabric  60 . In the configuration of  FIG. 22 , reed  48  has been withdrawn so that the warp strands can be repositioned. 
     In a first step following the withdrawal of reed  48 , wall strands  28 W in region  122  are moved upwards, as shown in  FIG. 23 . 
     In a second step ( FIG. 24 ), wall strands  28 W in region  124  are moved downwards. 
     In a third step ( FIG. 25 ), conductive warp strand  28 C is moved upwards in region  122  and a first insulating warp strand  28 I is moved downwards in region  124 . 
     In a fourth step ( FIG. 26 ), a first insulating warp strand  28 I is moved upwards in region  122  and conductive warp strand  28 C is more downwards in region  124 . 
     In a fifth step ( FIG. 27 ), a second of the insulating warp strands  28 I in region  122  is moved up and a second of the insulating warp strands  28 I in region  124  is moved down. At the completion of this step, the stack of warp strands in region  122  has an upper strand that is conductive (strand  28 C) and two lower strands that are insulating (strands  28 I) and corresponds to the configuration of region  122  of  FIG. 15 , whereas the stack of warp strands in region  124  has a central conductive strand  28 C sandwiched between opposing upper and lower insulating strands  28 I and corresponds to the configuration of region  124  in  FIG. 15 . 
     Additional picks such as the illustrative pick illustrated in  FIGS. 14-27  (with the same warp strand movements or other suitable movements) may be performed to complete the process of forming fabric  60 . As the example of  FIGS. 14-27  demonstrates, warp strand placement within the warp strand stacks (i.e., the stacks of three warp strands between opposing weft strands in the examples of  FIGS. 14-27 ) is controlled by controlling the relative timing of the warp strand position (shed height) for each of the warp strands. 
       FIG. 28  is graph in which warp strand vertical position (shed height) has been plotted as a function of time for an illustrative fabric containing a pair of wall strands  28 W and a stack of three warp strands (two insulating strands  28 I and one conductive strand  28 C) between the wall strands. The times at which the weft strands are inserted is given by weft strand insertion time  64 T. The graph of  FIG. 28  illustrates how different types of regions may be created in fabric  60  by controlling warp strand placement. In each pick, the wall warp strands  28 W are positioned first, thereby creating a gap into which a stack of strands  28 I and  28 C may be placed. 
     In pick  126 , the warp strands are being positioned to pass under the weft strand. Conductive warp strand  28 C is sandwiched between a pair of insulating warp strands  28 I. Pick  126  therefore creates an insulated back (lower surface) portion of fabric  60 . 
     In pick  128 , the warp strands are passing over the weft strand. Conductive warp strand  28 C is again sandwiched between a pair of insulating warp strands  28 I. Pick  128  therefore creates an insulated front (upper surface) portion of fabric  60 . 
     In pick  130 , the warp strands are passing under the weft strand. Conductive warp strand  28 C is inserted into the gap between wall strands  28 W before the two insulating strands  28 I, so pick  130  produces a region of fabric  60  in which conductive warp strand  28 W is exposed on the back of fabric  60 . 
     In pick  132 , the warp strands are passing over the weft strand. Conductive warp strand  28 C is inserted into the gap between wall strands  28 W before the two insulating strands  28 I, so pick  132  produces a region of fabric  60  in which conductive warp strand  28 W is exposed on the front of fabric  60 . 
     Although the graph of  FIG. 28  shows how different regions of fabric  60  may be formed using weaving techniques, conductive and insulating strands may likewise be selectively exposed on the front and back of a knitted fabric, in braided items, etc. Using weaving techniques to form fabric regions with both insulating and conductive exposed regions is merely illustrative. 
     It may be desirable to form fabric  60  with a weave such as a single-layer weave that allows selective open circuits and short circuits to be formed where conductive warp and weft strands intersect. Consider, as an example, the warp and weft intersections of  FIGS. 29 and 30 . In the illustrative configuration of  FIG. 29 , conductive warp strand  28 C and conductive weft strand  64 C intersect (i.e., strands  28 C and  64 C cross each other at a right angle or other suitable non-zero angle) but do not electrically connect. As a result, warp strand  28 C and weft strand  64 C form an open circuit at intersection  136  of  FIG. 29 . In the illustrative configuration of  FIG. 30 , strands  28 C and  64 C physically and electrically connect to each other at intersection  136  (i.e., intersection  136  is a short circuit). 
     Signal paths may be formed within fabric  60  using a desired pattern of open circuit intersections of the type shown in  FIG. 29  and short circuit intersections of the type shown in  FIG. 30 . As an example, an inductor such as inductor  134  of  FIG. 31  may be formed by creating a spiral conductive path that terminates at terminals T 1  and T 2 . in this way (e.g., to form busses and other signal routing paths). 
     An illustrative woven fabric of the type that may be provided with selectively formed open circuit and short circuit conductive strand intersections is shown in  FIG. 32 . As shown in  FIG. 32 , fabric  60  may contain multiple sets of insulating weft strands interwoven with multiple orthogonal sets of insulating warp strands using a basket weave pattern. In  FIG. 32 , there are three pairs of insulating weft strands  64 - 1 ,  64 - 2 , and  64 - 3  and three interwoven orthogonal pairs of insulating warp strands  28 - 1 ,  28 - 2 , and  28 - 3 . In this example, each set of insulating weft strands includes two weft strands and each set of interwoven insulating warp strands includes two warp strands. More insulating weft and/or warp strands may be provided in each set if desired. 
     Conductive warp strands (e.g., bare metal strands) may be inserted within some of the warp strand pairs and conductive weft strand pairs may be inserted within some of the weft strand pairs. In the illustrative configuration of  FIG. 32 , conductive weft strand  64 C has been inserted in the middle of weft strands  64 - 2  and conductive warp strand  28 C has been inserted in the middle of warp strands  28 - 2 . 
     The conductive warp and weft strands intersect at intersections such as intersection  136  of  FIG. 32 . When it is desired to form an open circuit between conductive weft strand  64 C and conductive warp strand  28 C at intersection  136 , the insulating strands adjacent to intersection  136  are interposed between strands  64 C and  28 C. As shown in  FIG. 32 , for example, insulating warp strands  28 - 2  and insulating weft strands  64 - 2  may be used to hold conductive strands  64 C and  28 C apart from each other. When it is desired to form a short circuit between weft strand  64 C and conductive warp strand  28 C at intersection  136 , weft strand  64 C may be configured to contact strand  28 C (i.e., strand  64 C may pass under strand  28 C at intersection  136  of  FIG. 32 ). 
     In the example of  FIG. 32 , each insulating weft strand passes over two insulating warp strands and then under two insulating warp strands in a repeating pattern. Similarly, each insulating warp strand passes over two insulating weft strands before passing under two insulating weft strands in a repeating pattern. Conductive strands  64 C and  28 C may follow the same pattern or may follow different paths. In the example of  FIG. 32 , warp strand  28 C passes alternately over and under pairs of insulating weft strands, but weft strand  64 C passes over one of warp strands  28 - 1  at intersection  138 - 1  (i.e., the warp strand  28 - 1  that is closest to intersection  136 ) and passes under the other of warp strands  28 - 1  and weft strand  64 C also passes over one of warp strands  28 - 3  at intersection  138 - 3  (i.e., the warp strand  28 - 3  that is closest to intersection  136 ) and passes under the other of warp strands  28 - 3 . If desired, fabric  60  could be configured so that strand  64 C passes under strand  28 - 1  at intersection  138 - 1  and so that strand  64 C passes under strand  28 - 3  at intersection  138 - 3 . The arrangement of  FIG. 32  is merely illustrative. 
       FIGS. 33 and 34  are respectively front and rear views of a fabric such as fabric  60  of  FIG. 32  in the vicinity of an illustrative open circuit intersection  136 . As shown in  FIGS. 33 and 34 , insulating strands  64 - 2  and  28 - 2  are drawn into the area between conductive strands  64 C and  28 C at illustrative open circuit intersection  136 , thereby preventing contact between conductive strands  64 C and  28 C. 
     Cross-sectional side views of fabric  60  of  FIG. 32  at a short circuit intersection and an open circuit intersection are shown respectively in  FIGS. 35 and 36 . As shown by the illustrative open circuit intersection  136  of  FIG. 35 , there are two layers of interposed insulating strands  28 - 2  and  64 - 2  that separate conductive strands  64 C and  28 C at the open circuit intersection. As shown by the illustrative short circuit intersection  136  of  FIG. 36 , a short circuit connection between strands  28 C and  64 C may be formed by passing strand  64 C under strand  28 C so that strands  28 C and  64 C are pulled towards each other and form a satisfactory electrical contact. 
     If desired, circuitry  16  may contain touch sensor array controller circuitry that emits drive signals onto a first set of conductive electrodes and that gathers and processes corresponding sense signals on a second set of conductive electrodes (e.g., overlapping electrodes or other electrodes that are associated with the first set of electrodes). The touch sensor array controller circuitry can emit the drive signals and can process the sense signals to gather touch input data (e.g., information on where a user&#39;s fingers or other external objects are located in lateral dimensions X and Y on a touch sensor formed from an array of the electrodes). In fabric-based device  10 , touch sensor electrodes may be formed from conductive paths that are selectively formed within fabric  60 . As an example, drive lines may be formed from conductive strands  28 C and sense lines may be formed from orthogonal conductive strands  64 C (or vice versa). Conductive strands  28 C and  64 C may intersect at open circuit intersections  136 . Due to the intervening insulating strands, the separation between conductive strands  28 C and  64 C will and the capacitance associated with this separation in the absence of a nearby external object will be well defined at each intersection. In this type of configuration, capacitive touch sensor data may be gathered at each intersection and, when processed by circuitry  16 , can be used to supply item  10  or other equipment (e.g., item  18 ) with touch sensor data (e.g., data on multi-touch gestures, single-touch gestures, etc.). Conductive strands  28 C and  64 C may also be used in forming other conductive structures in fabric  60  and item  10  (e.g., structures for a resistive sensor in a switch or touch sensor or structures for other electrical components). The use of fabric  60  to form a capacitive touch sensor is merely illustrative. If desired, fabric such as the fabric described in connection with  FIGS. 3-28  may be used in forming a capacitive touch sensor, resistive sensor, or other component (e.g., by selectively exposing conductive stacked strands to the front or back surfaces of fabric  60 , etc.). 
     The weaving techniques used in forming fabric  60  may be used in forming single-strand signal paths, signal paths that use patches of conductive strands to form electrodes or other structure, or other conductive paths. 
     In accordance with an embodiment, a fabric is provided that includes first strands that run along a first dimension, and interwoven second strands that run along a second dimension that is orthogonal to the first dimension, the second strands include pairs of insulating strands that are interwoven with the first strands and include stacked strands located between opposing first and second insulating strands in each pair of insulating strands and wherein the stacked strands include conductive and insulating stacked strands. 
     In accordance with another embodiment, the fabric has at least one portion in which one of the conductive stacked strands is sandwiched between a pair of the insulating stacked strands. 
     In accordance with another embodiment, at least one of the first strands is a conductive first strand. 
     In accordance with another embodiment, the conductive first strand and the conductive stacked strand intersect at an open circuit intersection in which the conductive first strand and the conductive stacked strand are isolated from each other. 
     In accordance with another embodiment, the conductive first strand and the conductive stacked strand are isolated from each other by one of the insulating stacked strands at the open circuit intersection. 
     In accordance with another embodiment, the fabric includes first and second fabric layers, the first and second strands are in the first layer. 
     In accordance with another embodiment, the fabric has opposing first and second surfaces and has at least one portion in which one of the conductive stacked strands is positioned above a pair of the insulating stacked strands and is exposed at the first surface. 
     In accordance with another embodiment, at least one of the first strands is a conductive first strand. 
     In accordance with another embodiment, the conductive first strand and the conductive stacked strand intersect at a short circuit intersection in which the conductive first strand and the conductive stacked strand contact each other and are shorted to each other. 
     In accordance with another embodiment, the fabric includes first and second fabric layers, where the first and second strands are in the first layer. 
     In accordance with another embodiment, the first strands are weft strands and the second strands are warp strands. 
     In accordance with another embodiment, the conductive stacked strands include bare metal wires. 
     In accordance with another embodiment, at least one of the conductive stacked strands forms at least part of a capacitive touch sensor electrode. 
     In accordance with an embodiment, a fabric is provided that includes first pairs of insulating strands interwoven with second pairs of insulating strands, the first pairs of insulating strands extend along a first dimension and the second pairs of insulating strands extend along a second dimension that is orthogonal to the first dimension, a first conductive strand that extends along the first dimension and that is interposed between first and second insulating strands in one of the first pairs of insulating strands, and a second conductive strand that extends along the second dimension and that is interposed between first and second insulating strands in one of the second pairs of insulating strands. 
     In accordance with another embodiment, the first conductive strand and the second conductive strand cross each other at an open circuit intersection in which the first and second conductive strands do not contact each other. 
     In accordance with another embodiment, the first and second conductive strands are held apart at the open circuit intersection by one of the first pairs of insulating strands and by one of the second pairs of insulating strands. 
     In accordance with another embodiment, the first and second conductive strands include bare metal wire. 
     In accordance with another embodiment, the first conductive strand and the second conductive strand cross each other at a short circuit intersection in which the first and second strands contact each other and are electrically shorted to each other. 
     In accordance with another embodiment, the first and second conductive strands include bare metal wire. 
     In accordance with another embodiment, at least one of the first and second conductive strands forms at least part of a capacitive touch sensor electrode. 
     In accordance with an embodiment, a fabric is provided that includes insulating warp strands that extend along a first dimension, and interwoven insulating weft strands that extend along a second dimension that is orthogonal to the first dimension, the insulating warp strands include pairs of insulating warp strands, the insulating weft strands include pairs of insulating weft strands, and the pairs of insulating warp strands and the pairs of insulating weft strands are interwoven, and a conductive warp strand that extends along the first dimension and that lies between the insulating wrap strands in one of the pairs of insulating warp strands, and a conductive weft strand that extends along the second dimension and that lies between the insulating weft strands in one of the pairs of insulating weft strands. 
     In accordance with another embodiment, the pairs of insulating warp strands and the pairs of insulating weft strands are interwoven in a basket weave and the conductive warp and weft strands intersect at an open circuit intersection and are held apart by some of the insulating warp and weft strands. 
     In accordance with another embodiment, the pairs of insulating warp strands and the pairs of insulating weft strands are interwoven in a basket weave and the conductive warp and weft strands intersect at a short circuit intersection in which the conductive warp and weft strands contact each other. 
     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: 20160212
Publication Date: 20200728
Grant Date: 20200728
Priority Date: 20150213
Inventors: PODHAJNY, DANIEL A.
SUNSHINE, Daniel D.
CREWS, KATHRYN P.
Assignee: APPLE INC
CPC Classifications: [{"code": "D03D15/00", "inventive": true, "first": true, "tree": "[]"}, {"code": "D03D15/67", "inventive": true, "first": false, "tree": "[]"}, {"code": "D03D15/67", "inventive": true, "first": false, "tree": "[]"}, {"code": "D03D15/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "D03D15/00", "inventive": true, "first": true, "tree": "[]"}, {"code": "D03D15/67", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K2201/0281", "inventive": false, "first": false, "tree": "[]"}, {"code": "D10B2401/16", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K1/038", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K1/0283", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K1/0283", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K2201/0281", "inventive": false, "first": false, "tree": "[]"}, {"code": "D10B2401/16", "inventive": false, "first": false, "tree": "[]"}, {"code": "D10B2401/16", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K1/0283", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K1/038", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K2201/0281", "inventive": false, "first": false, "tree": "[]"}, {"code": "D02G3/441", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K1/038", "inventive": false, "first": false, "tree": "[]"}, {"code": "D10B2101/20", "inventive": false, "first": false, "tree": "[]"}, {"code": "D10B2401/16", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K1/0283", "inventive": false, "first": false, "tree": "[]"}, {"code": "D02G3/441", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K2201/0281", "inventive": false, "first": false, "tree": "[]"}, {"code": "D10B2101/20", "inventive": false, "first": false, "tree": "[]"}, {"code": "D03D15/00", "inventive": true, "first": true, "tree": "[]"}, {"code": "H05K1/038", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 55456913