Weaving equipment with strand modifying unit

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. One or more of the warp strands may be selectively modified along its length using a warp strand modification unit. The warp strand modification unit may be interposed between the fabric and a reed, may be interposed between the fabric and the warp strand positioning equipment, may be mounted to the reed, or may be incorporated elsewhere in the weaving equipment. Warp strand modifications may include adding segments of metallic paint coatings or other conductive coatings, adding insulating coatings, applying other liquids to segments of the warp strand, modifying the stretchiness of warp strands, removing material from segments of the warp strand, and attaching electrical components to the warp strand.

BACKGROUND

This relates generally to weaving and, more particularly, to equipment for processing strands during weaving.

It may be desirable to form fabric from strands of material that are treated differently at different locations along their lengths. Strands may, for example, be dyed with different colors at different locations. Strands of this type may be woven together to produce fabric with colored patterns.

In warp ikat fabrics, warp threads are printed with specific patterns. It can be challenging to use traditional weaving equipment to form fabrics such as warp ikat fabrics in which the printed patterns are aligned as desired with the underlying structures of a fabric (i.e., the connecting warp and weft threads that determine the fabric's construction and properties). In most looms, there is a relatively long distance between the warp beam and the fabric being woven. As a result, it can be difficult to accurately position warp strands with respect to each other and with respect to the weft strands that are being used to form the fabric. Adjacent warp strands can become misaligned with respect to each other and may not align properly with the weft strands. This can make it impossible to form precise patterns in the fabric. More accurate weaving would allow improved fabric-based items to be formed.

It would therefore be desirable to be able to process strands at various locations along their lengths in a way that facilitates accurate weaving with the processed strands.

SUMMARY

Fabric may be formed by weaving warp strands and weft strands together using weaving equipment. The weaving equipment may include warp strand positioning equipment that positions the warp strands to produce a shed and weft strand positioning equipment that inserts weft strands into the warp strands to form the fabric. Strands may be selectively modified prior to weaving. For example, one or more of the warp strands may be selectively modified along its length using a warp strand modification unit.

A warp strand modification unit may be located adjacent to the edge of the fabric that is being woven. This allows warp strand segments that have been modified to be accurately aligned with desired weft strands. For example, a segment of a warp strand may be positioned to overlap a particular weft strand.

The warp strand modification unit may be interposed between the fabric and a reed, may be interposed between the fabric and the warp strand positioning equipment, may be mounted to the reed, or may be incorporated elsewhere in the weaving equipment.

The warp strand modification unit may add segments of metallic paint coatings or other conductive coatings, may add insulating coatings, may apply liquids to segments of the warp strands such as liquids that modify the stretchiness of warp strands and that remove material from segments of the warp strands, may attach electrical components to the warp strands, and may otherwise selectively modify the warp strands.

DETAILED DESCRIPTION

Selectively modified strands may be incorporated into strand-based items such as strand-based item ofFIG. 1. Item10may 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'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 item10is 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, item10may 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 strand-based item10may 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. Strand-based item10may be soft (e.g., item10may have a fabric surface that yields to a light touch), may have a rigid feel (e.g., the surface of item10may 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.

Item10may include intertwined strands12. The strands may be intertwined using strand intertwining equipment such as weaving equipment, knitting equipment, or braiding equipment. Intertwined strands12may, for example, form woven fabric.

Strands12may be single-filament strands 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 fibers 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 may also be formed from single-filament metal wire, multifilament wire, or combinations of different materials. Strands may be insulating or conductive. Strands may be conductive along their entire length or may have conductive segments (e.g., metal portions that are exposed by locally removing insulation or that are formed by 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 fibers and insulating fibers (e.g., metal strands or metal coated strands with or without exterior insulating layers may be used in combination with solid plastic fibers or natural fibers that are insulating).

Item10may include additional mechanical structures14such as polymer binder to hold strands12together, support structures such as frame members, housing structures (e.g., an electronic device housing), and other mechanical structures.

Circuitry16may be included in item10. Circuitry16may include components that are coupled to strands12, components that are housed within an enclosure formed by strands12, components that are attached to strands12using welds, solder joints, adhesive bonds (e.g., conductive adhesive bonds), crimped connections, or other electrical and/or mechanical bonds. Circuitry16may 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. Circuitry16may 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.

Item10may interact with electronic equipment or other additional items18. Items18may be attached to item10or item10and item18may 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.).

As shown inFIG. 1, circuitry16may include antennas and other structures for supporting wireless communications with item18. Item18may also interact with strand-based item10using a wired communications link or other connection that allows information to be exchanged.

In some situations, item18may be an electronic device such as a cellular telephone, computer, or other portable electronic device and strand-based item10may form a case or other structure that receives the electronic device in a pocket, an interior cavity, or other portion of item10. In other situations, item18may be a wrist-watch device or other electronic device and item10may be a strap of other strand-based item that is attached to item18. In still other situations, item10may be an electronic device, strands12may be used in forming the electronic device, and additional items18may include accessories or other devices that interact with item10.

If desired, magnets and other structures in items10and/or18may allow items10and18to interact wirelessly. One item may, for example, include a magnet that produces a magnetic field and the other item may include a magnetic switch or magnetic sensor that responds in the presence of the magnetic field. Items10and18may also interact with themselves or each other using pressure-sensitive switches, pressure sensors, force sensors, proximity sensors, light-based sensors, interlocking electrical connectors, etc.

The strands that make up item10may be intertwined using any suitable strand intertwining equipment. With one suitable arrangement, which may sometimes be described herein as an example, strands12may be woven together to form a 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 item10ofFIG. 1is shown inFIG. 2. As shown inFIG. 2, weaving equipment22may be provided with strands such as strands12ofFIG. 1from strand source24. The strands provided by strand source24may 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.

Source24may supply warp strands28from warp beam80. Warp beam80may be implemented using a drum or other structure that rotates about rotational axis78in direction76. Warp strands24may be dispensed between rollers26as the drum rotates.

Warp strands28may be positioned using warp strand positioning equipment74. Equipment74may include strand positioning structures such as harness80. Harness80may be controlled using control circuitry70to control the positions of strands28.

As shown inFIG. 2, harness80may include heddles36. Heddles36may each include an eye30mounted on a wire that extends between a respective one of springs38and a respective one of wire positioners42or may use other structures for positioning warp strands28. Wire positioners42may be motors (e.g., stepper motors) or other electromechanical actuators. Some or all of heddles36may be independently positioned. During operation, control circuitry70may supply control signals on outputs72that move each heddle by a desired amount (e.g., up or down in directions32). By raising and lowering the heddles in various patterns in response to control signals from control circuitry70, different patterns of gaps (sheds)66between warp strands28may be created.

Weft strand58may be inserted into sheds66during weaving to form fabric60. Weft strand positioning equipment62may be used to place weft strand58between the warp strands forming each shed66. Weft strand positioning equipment62may 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 strand64is made through shed(s)66, reed48may be moved in direction50(e.g., reed48may be rotated about axis46) to push the weft strand that has just been inserted into the shed between respective warp strands28against previously woven fabric60, thereby ensuring that a satisfactorily tight weave is produced. Fabric60that has been woven in this way may be gathered on take-down roller82as roller82rotates in direction86about rotational axis84. Reed48and weft strand positioning equipment62may be controlled by control signals from control outputs72.

Strand modification equipment such as strand modification unit52may be used in processing one or more warp strands28. As shown inFIG. 2, strand modification unit52may have positioning equipment such as computer-controlled positioner54and strand processing head56(or, if desired, multiple positioners54coupled to multiple respective heads56).

Each positioner54and processing head56may be controlled by control circuitry70using control signals on control outputs72. The position of head56may, for example, be adjusted by positioner54to place head56in and out of use. As one example, head56may contain a liquid-soaked pad. The liquid may be a colored ink or other colorant or may be other liquid. When it is desired to apply the liquid to warp strand28, positioner54may move head56into contact with warp strand28. When it is desired to terminate the liquid application process, positioner54may pull head56away from warp strand28. The positions of strands28relative to heads such as head56may also be controlled using warp strand positioning equipment74(whether or not equipment74is being used to position strands28to form sheds66to accommodate weft strand64).

The application of liquids such as inks to strand28is merely an illustrative example of a potential strand modification that may be made using unit52. Other liquids may also be applied (e.g., metallic paint, material for removing selected portions of strand28, insulating material such as adhesive, etc.). In general, unit52may be used to apply material, remove material, change strand28or portions of strand28by application of energy, may mechanically alter strand28, or may otherwise process strand28.

Strand modification unit52may, for example, be used to apply material to strand28. The applied material may be used to selectively adjust the properties of strands28. For example, material may be applied to strand28that changes the stiffness of strand28. If strand28is relatively flexible and stretchable, the applied material may locally increase the stiffness of strand28and thereby reduce flexibility and stretchability. If strand28is relatively stiff, the applied material may locally increase the flexibility and/or stretchability of strand28.

Unit52may also be used to apply conductive material (e.g., conductive adhesive, metallic paint, etc.) to strand28. The conductive material may selectively increase the conductivity of strand28. If, as an example, strand28is formed from a polymer strand or other dielectric strand, use of unit52to apply a conductive adhesive or metallic paint to strand28to one or more segments of strand28can render the one or more segments of strand28conductive.

If desired, unit52may also be used to apply a solvent such as an etchant or other substance that removes material from strand56(e.g., to strip polymer insulation from the outer surface of a metal wire, etc.). With this type of arrangement, strand28may have an insulating coating except where strand28has been stripped of insulation with the solvent to allow electrical components to be attached to strand28.

Other techniques may also be used to selectively remove material from strand28or to selectively texture or otherwise treat exterior of portions of strand28. These techniques may involve applying energy (light, heat, electricity, plasma, etc.) to strand28. The application of energy to strand28may locally remove a conductive or insulating exterior coating. For example, a conductive coating on a dielectric strand may be locally removed to form an insulating segment between two conductive segments or an insulating coating on a metal strand may be locally removed to form a strand segment with a conductive surface between two insulated strand portions.

Cutting blades and other mechanical equipment may be used to process strand28(e.g., to remove insulation, to remove a conductive coating, to roughen the exterior of strand28, etc.). The coatings that are applied to strand28by unit52may include colored materials (e.g., colored inks), may include dyes, pigments, adhesives, polymers, conductive materials, etchants and other solvents for selectively removing dielectric and/or metallic materials from strand28, etc.

As part of the processing of strand28by unit52, electrical components may be crimped into place on strand28or may be electrically and mechanically mounted on strand28using other techniques (e.g., soldering, etc.).

Unit52may be located adjacent to edge88of fabric60, so that the accuracy with which the processed portion of strand28is placed within fabric60is enhanced. With this type of arrangement, modifications to warp strand28take place just as strand28is being incorporated into fabric60, so that there is a reduced possibility that the selectively modified portions of each strand28will shift out of desired alignment with respect to weft strands64. Accurate placement of the processed warp strand portions relative to weft strands64may allow electrical connections to be made for signal paths, may ensure that locally insulated strand segments are properly aligned with other strands, etc.

If desired, unit52may be mounted on reed48in a location such as illustrative mounting location49, may be placed between reed48and warp strand positioning equipment74(e.g., in a location such as illustrative mounting location51), or may be mounted elsewhere in equipment22. The configuration ofFIG. 2in which strand modification unit52is located between reed48and fabric60is merely illustrative.

FIG. 3is a diagram showing different types of equipment that may be included in unit52for processing strand28. As shown inFIG. 3, unit52may include coating application tool92. Coating application tool92may be used to apply one or more coatings90. Coatings90may include conductive coatings, dielectric coatings, and other layers of material. Coating application tool92may include one or more pads impregnated with liquid coating materials, may include inkjet coating application equipment, may include equipment for applying liquid coatings using spraying or dipping, or may include other tools for applying coatings90to strand28.

Solvent application tool96may be used to apply solvent94. Solvent94may include chemicals that remove dielectric and/or conductive materials from strand28(e.g., metal etchant for removing metal, a polymer solvent for dissolving and removing polymer, an etchant for removing inorganic dielectric, etc.). Solvent application tool96may include equipment for ink-jet coating, spray coating, pad-based coating, dipping, or other or other tools for supplying liquid solvent94to strand28.

Unit52may include one or more mechanical treatment tools such as tool98. The mechanical treatment tools may be used to remove coatings, to change the texture of strand28, or to otherwise process strand28. Tool98may include equipment for cutting strand28, for scoring strand28, for roughening the surface of strand28, for bending strand28, or for otherwise mechanically processing strand28.

If desired, other equipment100may be used in processing strand28. Equipment100may include a heat source (e.g., a flame, a heated metal structure or other heated structure, a lamp that produces heat, etc.). Equipment100may also include a laser, light-emitting diode, or other light source (e.g., an infrared laser or infrared light-emitting diode, a visible laser or visible light-emitting diode, and/or an ultraviolet laser or light-emitting diode). By applying heat or light or other energy to strand28, coatings can be selectively removed, liquid polymers and other coating materials may be cured, the texture of strand28may be altered, or other strand modifications can be made.

Equipment100may be used in attaching electrical components such as electrical components in circuitry16ofFIG. 1to strand28. For example, equipment100of unit52may be used to attach electrical components to strand28using solder joints, crimped metal connections, welds, conductive adhesive, or other conductive attachment structures. The electrical components that are attached to strand28in this way may include light-emitting components, integrated circuits, light-emitting diodes, light-emitting diodes that are packaged with transistor-based circuitry such as communications circuitry and/or light-emitting diode driver circuitry that allows each component to operate as a pixel in a display, discrete components such as resistors, capacitors, and inductors, audio components such as microphones and/or speakers, sensors such as touch sensors (with or without co-located touch sensor processing circuitry), accelerometers, temperature sensors, force sensors, microelectromechanical systems (MEMS) devices, transducers, solenoids, electromagnets, pressure sensors, light-sensors, proximity sensors, buttons, switches, two-terminal devices, three-terminal devices, devices with four or more contacts, etc. Electrical connections for attaching electrical components to strand28using equipment100may be formed using solder, conductive adhesive, welds, molded package parts, mechanical fasteners, wrapped strand connections, press-fit connections, crimped connections (e.g., bend metal prong connections), and other mechanical connections, portions of liquid coatings (e.g., metallic paint, conductive adhesive, etc.) that are selectively applied to strand28using unit52, or using any other suitable arrangement for forming an electrical short between conductive structures.

FIG. 4is an end view of a unit52in an illustrative embodiment where unit52is dispensing patches of adhesive to strand28. Adhesive106may be conductive adhesive to help form conductive joints between overlapping warp and weft strands or may be insulating adhesive to help electrically isolate overlapping warp and weft strands.

As shown inFIG. 4, unit52may include rollers102. Rollers102may be controlled by motors that receive control signals from control circuitry70. Rotation of rollers102may be used to move belt108and thereby control the lateral position of adhesive pads106relative to strand28. Using pad104(e.g., a pad of a foam material or other compressible material), unit52can press adhesive106onto strand28, as shown inFIG. 4. Pad104can be pressed downward towards strand28using positioner54and/or positioning equipment74may control heddles80so that strand28is drawn upwards against pad104and belt108.

Illustrative coating equipment for use in unit52of system22is shown inFIG. 5. In the example ofFIG. 5, unit52has three coating application heads56A,56B, and56C having respective computer-controlled support structures110A,110B, and110C that adjust the positions of corresponding liquid-filled foam pads112A,112B, and112C. The positions of each head can be adjusted by a respective positioner such as positioner54ofFIG. 2. Pads112A,112B, and112C may be filled with liquids of different properties (e.g., different colors of ink, different adhesives, different metallic paints, solvents, combinations of these liquids and/or other liquids, etc.). When it is desired to coat strand28with the liquid in pad112A, support structure110A may be moved towards strand28. When it is desired to coat strand28with the liquid in pad112B, support structure110B may be moved towards strand28. Support structure110C may be moved towards strand28when it is desired to coat strand28with the liquid in pad112C.

When using coating equipment of the type shown inFIG. 5, only one side of strand28may be coated absent rotation of strand28about its longitudinal axis.FIG. 6is a perspective view of a belt-based strand rotation device that may be used in unit52to help coat additional portions of strand28. As shown inFIG. 6, strand rotator114may have computer-controlled rollers116that are controlled by control signals from control circuitry70. Rollers116may be rotated to move belt118in direction124or in direction126. Strand28may extend along strand axis122. Belt118may contact the outer surface of strand28, so that movement of belt118in direction126or124rotates strand28respectively in direction120or130about axis122.

By rotating strand28with rotator114, head56or other coating equipment in system22can coat all surfaces (top and bottom) of strand28.FIG. 7is a cross-sectional view of strand28in a scenario in which the upper surface of strand28has been coated with coating132(e.g., dielectric, metallic paint, etc.). In the illustrative scenario ofFIG. 8, the upper surface of strand28has been coated with coating132and, following rotation about axis122by strand rotation equipment114ofFIG. 6or other equipment, the lower surface of strand28has been coated with coating134.FIG. 9is a cross-sectional view of strand28in a scenario in which both the upper and lower surfaces of strand28have been coated with coating132by rotating strand28about axis122during the coating process (e.g., using rotator144ofFIG. 6).

FIG. 10is a perspective view of an illustrative electrical component mounted to strand28. As shown inFIG. 10, strand28may have a dielectric core28D and electrically isolated segments with respective conductive coatings132-1and132-2. Electrical component140(e.g., an integrated circuit, a light-emitting diode or other light source, a sensor, etc.) may have terminals142-1and142-2. Terminals142-1and142-2may be formed from metal and may be crimped using unit52. As shown inFIG. 10, for example, terminal142-1may be crimped to form a connection to metal coating segment132-1and terminal142-2may be crimped to form a connection to metal coating segment132-2.

In the illustrative configuration ofFIG. 10, component140has two terminals. In general, component140may have any suitable number of terminals (three, four, etc.). Crimped connections, solder connections, conductive adhesive connections, welds, or other electrical connections may be used by unit52to couple the terminals of component140to the metal coating portions of strand28. If desired, strand28may have a metal core and an insulating coating. The configuration ofFIG. 10in which metal segments have been formed on the exterior surface of a dielectric strand core is merely illustrative.

FIG. 11is a top view of fabric60showing how warp strands28may be woven with weft strands64. Just prior to being woven into fabric60, unit52may modify strand28to add conductive segments132-1and132-2and to add electrical component140. Weaving can then continue using system22until fabric60ofFIG. 11is formed. In the example ofFIG. 11, some of weft strands64(i.e., strands64D) are formed from dielectric or have a dielectric coating and therefore have insulating surfaces, whereas other weft strands64(i.e., strands64C-1and64C-2) are formed from metal or dielectric with metal coating and are therefore have conductive surfaces. By modifying warp strands such as warp strand28ofFIG. 11just before the warp strand is woven with weft strands64to form fabric60, it is possible to accurately align and mate warp strand features such as conductive segments (terminals)132-1and132-2with respective overlapping weft strand features such as conductive weft strands64C-1and64C-2. This allows conductive weft strand64C-1to serve as a signal line to carry signals to conductive segment132-1on strand28, which is coupled to terminal142-1of component140. Conductive weft strand64C-2can serve as a signal line that carries signals to conductive segment132-2on strand28, which is coupled to terminal142-2of component140. Strands such as strands64C-1and64C-2may be interconnected with other conductive strands that form signal paths that couple component140into circuitry16for a fabric-based item such as strand-based item10.

In the illustrative example ofFIG. 12, strand segments132(e.g., conductive coating, insulating coating, portions of an insulated wire that have been stripped of insulation, etc.) may be formed on warp strands28with unit52just before warp strands28are incorporated into fabric60with weft strands64. Because segments132(e.g., conductive coating, etc.) are patterned onto warp strands28just before fabric60is formed, segments132may be accurately aligned along dimension Y, so that each segment overlaps a desired one of weft strands64running along perpendicular dimension X.

Weft strands64ofFIG. 12may include one or more bare metal wires or metal-coated wires that are shorted to conductive metal segments132wherever the conductive metal segments overlap strands64. The conductive segments132and weft strands64may be patterned to form a sensor (e.g., a capacitive touch sensor for a button), may be used to form interconnects (e.g., conductive paths for signals in circuitry16such as conductive paths that interconnect components such as component140to other circuitry), or may be used to form other suitable structures for item10.

In the illustrative example ofFIG. 13, the ability to accurately align warp strand portions132with desired weft strands64has been used to form conductive signal path152. As shown inFIG. 13, signal path152has been formed by overlapping end150A of conductive segment132A on warp strand28A with weft strand64CP and by overlapping end150B of conductive segment132B on warp strand28B with weft strand64CP. Weft strand64CP may, as an example, be a conductive strand and segments132A and132B may be conductive segments from metal coatings and/or bared metal cores of insulated strands. Path152may be formed by coupling these conductive strand portions together as shown inFIG. 13.

To prevent undesired short circuit paths in the illustrative configuration ofFIG. 13, the weft strands in fabric60other then conductive signal path weft strand64CP and the warp strand portions other than segments132A and132B may be insulating. In general, any suitable pattern of interconnects may be formed using overlapping conductive warp strand and weft strand portions. For example, signals may be routed across one or more warp strands, across one or more weft strands, may traverse one or more warp-to-weft and one or more weft-to-warp connections, etc.

Electrical connections in fabric60may be made by ensuring that the overlapping strand portions in a signal path are formed from conductive material (e.g., metal, metal in metallic paint, etc.). The metallic paint, conductive adhesive, or other material that is applied to strands28to form segments132may be dried and/or cured before overlapping strands28and strands64or wet liquid metallic paint, uncured liquid conductive adhesive, or other moist applied material may be used in forming electrical connections (i.e., strand28may be coated with metallic paint and woven with weft strands64before the metallic paint has completely dried).

If desired, connections may be augmented using conductive materials such as conductive adhesive, solder, metallic paint, or other conductive materials applied to the bare metal or metal coating of segments132using equipment such as unit52. Adding conductive material to the joints between overlapping strands in a signal path may help reduce resistance along the path. In some situations, additional conductive material can be omitted (e.g., when overlapping conductive strands form low-contact-resistance connections). This may help reduce fabrication complexity.

In some designs, it may be desirable for conductive strands to pass over each other without forming an electrical connection. Consider, as an example, a fabric in which warp strands28contain a mixture of insulating strands and conductive strands and in which weft strands64contain a mixture of insulating strands and conductive strands. The insulating strands may be, for example, polymer strands and the conductive strands may be, for example, bare metal strands or polymer strands coated with metal. In this type of arrangement, a given conductive warp strand may cross over a given conductive weft strand even though an electrical connection is not desired between these two strands. The conductive strands may overlap to form a desired pattern of signal interconnects, to form a capacitive touch sensor array (with each sensing point corresponding to an overlap between a warp and weft strand), or to form other structures for item10.

As shown inFIG. 14, for example, conductive warp strand28′ may be surrounded by adjacent insulating warp strands28and conductive weft strand64′ may be surrounded by adjacent insulating weft strands64. In the portion of fabric60that is shown inFIG. 14, it is not desired to form an electrical connection between conductive warp strand28′ and conductive weft strand64′ even though these two strands overlap. Accordingly, insulating layer1321has been added to warp strand28′ using unit52(e.g., equipment of the type shown inFIG. 4, equipment of the type shown inFIG. 3such as coating tool92, etc.). Insulating layer1321may be a polymer coating, a layer of adhesive such as adhesive106ofFIG. 4, or other dielectric coating. Insulating layer1321may be placed on the upper surface of strand28′ (see, e.g.,FIG. 7) or may cover both the top and bottom of strand28′ (see, e.g.,FIGS. 8 and 9in which strand28′ is surrounded with coating material).

As shown in the cross-sectional side view ofFIG. 15, strands28′ and64′ may be electrically isolated from each other using interposed insulating coating such as insulating layer1321.

When a dielectric material such as layer1321is interposed between respective conductive strands in fabric60, the conductive strands will not be electrically shorted to each other at direct current (DC) frequencies. This allows signals to be routed through the conductive strands without inadvertent shorts (i.e., the conductive strands may form a desired signal interconnect pattern in fabric60). If desired, the intersections at which conductive warp and weft strands overlap may serve as capacitive touch sensor electrodes (e.g., touch sensor locations in a mutual capacitance touch sensor array). In a capacitive touch sensor arrangement, alternating current (AC) drive signals may be applied to weft strands and sense signals may be gathered at warp strands that are separated from the weft strands by insulating portions1321or drive signals may be applied to the warp strands while sense signals are gathered at weft strands. Other types of capacitive touch sensor may be formed in which warp and weft strands are separated by insulating portions1321, if desired. The use of overlapping sense and drive signal paths formed from perpendicular conductive strands in fabric60is merely illustrative.