PATENT DOCUMENT

Publication Number: US-10400366-B2
Application Number: US-201815941325-A
Country: US
Kind Code: B2

Title: Fabric items having strands varying along their lengths

Abstract:
A fabric-based item may include fabric formed from intertwined strands of material. The strands of material may include extruded strands. Strand extrusion equipment may have electrically adjustable sources such as one or more sources of different polymers, dyes, particles, wire, and other elements to be incorporated into an extruded strand. The properties of the strands such as strand stiffness, strand diameter, conductivity, magnetic permeability, opacity, color, thermal conductivity, sand strength, may be varied along their lengths. Fabric formed from the strands may have different areas with different properties. Markers may be formed from particles at particular locations along the lengths of the strands, may be optical marker structures formed from circumferential rings of ink or other visible material on the strands, or may be other markers that can be sensed using electrical sensing, magnetic sensing, optical sensing, or other types of sensing when forming fabric from the strands.

Claims:
What is claimed is: 
     
       1. A fabric-based item comprising:
 a layer of fabric formed from extruded strands of material, wherein the layer of fabric has first and second areas, wherein the first area is formed from first portions of the extruded strands, wherein the second area is formed from second portions of the extruded strands, wherein the strands are characterized by a property that has a first value in the first portions and a second value in the second portions. 
 
     
     
       2. The fabric-based item defined in  claim 1  wherein the layer of fabric is configured to form an electronic device housing, wherein the fabric-based item further comprises wireless circuitry in the electronic device housing, wherein the first area overlaps the wireless circuitry, wherein the property comprises radio-frequency signal transparency, and wherein the first area is more radio-frequency transparent than the second area and serves as a radio-transparent window for the electronic device housing through which the wireless circuitry transmits and receives wireless signals. 
     
     
       3. The fabric-based item defined in  claim 1  wherein the property comprises strand diameter and wherein the first value is a first diameter and the second value is a second diameter that is larger than the first diameter. 
     
     
       4. The fabric-based item defined in  claim 1  wherein the property comprises conductivity and wherein the first value is a first conductivity and the second value is a second conductivity that is larger than the first conductivity. 
     
     
       5. The fabric-based item defined in  claim 1  wherein the property comprises optical transparency and wherein the first value is a first optical transparency and wherein the second value is a second optical transparency that is greater than the first optical transparency. 
     
     
       6. The fabric-based item defined in  claim 1  wherein the strands are extruded polymer strands, wherein the property comprises particle concentration in the extruded polymer strands, wherein the first value is a first particle concentration, and wherein the second value is a second particle concentration that is different than the first particle concentration. 
     
     
       7. The fabric-based item defined in  claim 1  wherein the property comprises color, wherein the first value is a first color, wherein the second value is a second color that is different than the first color, and wherein the first area is configured to form a key label symbol. 
     
     
       8. The fabric-based item defined in  claim 1  wherein the property comprises strand stiffness and wherein the first value is a first stiffness and wherein the second value is a second stiffness that is greater than the first stiffness. 
     
     
       9. The fabric-based item defined in  claim 1  wherein the strands include markers. 
     
     
       10. The fabric-based item defined in  claim 9  wherein the markers are each multi-element markers. 
     
     
       11. The fabric-based item defined in  claim 9  wherein the markers include magnetic particles in the strands. 
     
     
       12. The fabric-based item defined in  claim 9  wherein the markers include circumferential bands around the strands and wherein the markers are located at positions along the strands at which the first portions transition to the second portions. 
     
     
       13. A fabric, comprising:
 a layer of intertwined extruded strands of material having first and second areas, wherein the first area is formed from first portions of the extruded strands, wherein the second area is formed from second portions of the extruded strands, wherein the first portions are formed from polymer that includes particles with a given concentration, and wherein the second portions are formed from the polymer with less than the given concentration of particles. 
 
     
     
       14. The fabric defined in  claim 13  wherein the intertwined extruded strands of material comprise woven warp and weft strands and wherein the particles comprise metal particles. 
     
     
       15. The fabric defined in  claim 13  wherein the particles comprise magnetic particles. 
     
     
       16. The fabric defined in  claim 13  wherein the first area is characterized by a first optical transparency and wherein the second area is characterized by a second optical transparency that is greater than the first optical transparency. 
     
     
       17. Apparatus, comprising:
 fabric having strands of material with properties that vary along their lengths; and 
 a marker on each strand of material, wherein the marker comprises a marker selected from the group consisting of: a magnetic marker, a conductive marker, and an optical marker. 
 
     
     
       18. The apparatus defined in  claim 17 , wherein the fabric has a first area formed from first portions of the strands and a second area with different properties than the first area formed from second portions of the strands and wherein the marker on each strand is located between the first and second portions of that strand. 
     
     
       19. The apparatus defined in  claim 18  wherein the strands comprise extruded polymer and wherein the markers are formed from particles in the polymer. 
     
     
       20. The apparatus defined in  claim 18  wherein the strands comprise extruded polymer and wherein the markers comprise optical markers on the polymer.

Description:
This application claims the benefit of provisional patent application No. 62/519,398, filed Jun. 14, 2017, which is hereby incorporated by reference herein in its entirety. 
    
    
     FIELD 
     This relates generally to fabric-based items and, more particularly, to fabric-based items formed from strands of material such as extruded strands. 
     BACKGROUND 
     It may be desirable to form bags, furniture, clothing, wearable electronic devices, and other items from materials such as fabric. If care is not taken, however, fabric-based items may not offer desired features. For example, fabric-based items may include fabric that is completely uniform. The use of uniform fabric may make it difficult to satisfy design goals when forming a fabric-based item. 
     SUMMARY 
     A fabric-based item may include fabric formed from intertwined strands of material. The strands of material may include extruded strands such as extruded polymer strands. Strand extrusion equipment may have electrically adjustable sources such as one or more sources of different polymers, dyes, particles, wire, and other elements to be incorporated into an extruded strand. Adjustments may be made to the sources and to adjustable components in the extrusion equipment such as heaters, magnets, coating equipment, and other components so as to vary the properties of extruded strands along their lengths. For example, the properties of the strands such as strand stiffness, strand diameter, conductivity, magnetic permeability, opacity, color, may be varied along their lengths. 
     Fabric formed from the strands may have different areas with different properties. Markers may be formed from particles at particular locations along the lengths of the strands. The markers may be used by equipment for forming fabric to help identify the locations of different portions of the strands and thereby ensure that desired areas in the fabric are provided with desired properties. The markers may be formed from optical marker structures such as circumferential rings of ink or other material on the strands or other marker structures that can be sensed using electrical sensing, magnetic sensing, optical sensing, or other types of sensing when forming fabric from the strands. 
     Areas of a fabric-based item with different properties may overlap wireless components, optical components, or other components in the item. The fabric in this type of arrangement may form an electrical device housing or other structure that overlaps the components. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of an illustrative fabric-based item in accordance with an embodiment. 
         FIG. 2  is a side view of illustrative woven fabric in accordance with an embodiment. 
         FIG. 3  is a top view of illustrative knit fabric in accordance with an embodiment. 
         FIG. 4  is a diagram of illustrative equipment for forming a fabric-based item in accordance with an embodiment. 
         FIG. 5  is a diagram of illustrative strand extruding equipment in accordance with an embodiment. 
         FIG. 6  is a diagram of illustrative fabric with regions having different properties in accordance with an embodiment. 
         FIG. 7  is a diagram of an illustrative strand with a property that varies along its length in accordance with an embodiment. 
         FIG. 8  is a diagram of an illustrative strand with a diameter that varies along its length in accordance with an embodiment. 
         FIG. 9  is a diagram of an illustrative strand with a core that is being selectively altered at a location along its length in accordance with an embodiment. 
         FIG. 10  is side view of an illustrative item having a fabric housing with a window in accordance with an embodiment. 
         FIG. 11  is a diagram of illustrative fabric with a portion having a lowered melting temperature in accordance with an embodiment. 
         FIG. 12  is a side view of an illustrative strand of tubing configured to form a sensor in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Items such as item  10  of  FIG. 1  may be based on fabric. 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 remote control, 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 may be 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, sock, glove, shirt, pants, etc.), or may be any other suitable fabric-based item. 
     Item  10  may include intertwined strands of material that form fabric  12 . Fabric  12  may form all or part of a housing wall or other layer in an electronic device, may form internal structures in an electronic device, or may form other fabric-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. 
     The strands of material in fabric  12  may be single-filament strands (sometimes referred to as fibers or monofilaments), may be yarns or other strands that have been formed by intertwining multiple filaments (multiple monofilaments) of material together, or may be other types of strands (e.g., tubing that carries fluids such as gases or liquids). The strands may include extruded strands such as extruded monofilaments and yarn formed from multiple extruded monofilaments. Monofilaments for fabric  12  may include polymer monofilaments and/or other insulating monofilaments and/or may include bare wires and/or insulated wires. Monofilaments formed from polymer cores with metal coatings and monofilaments formed from three or more layers (cores, intermediate layers, and one or more outer layers each of which may be insulating and/or conductive) may also be used. 
     Yarns in fabric  12  may be formed from polymer, metal, glass, graphite, ceramic, natural materials 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 material. For example, plastic yarns and monofilaments in fabric  12  may be coated with metal to make them conductive. Reflective coatings such as metal coatings may be applied to make yarns and monofilaments reflective. Yarns may be formed from a bundle of bare metal wires or metal wire intertwined with insulating monofilaments (as examples). 
     Strands of material may be intertwined to form fabric  12  using intertwining equipment such as weaving equipment, knitting equipment, or braiding equipment. Intertwined strands may, for example, form woven fabric, knit fabric, braided fabric, etc. Conductive strands and insulating strands may be woven, knit, braided, or otherwise intertwined to form contact pads that can be electrically coupled to conductive structures in item  10  such as the contact pads of an electrical component. The contacts of an electrical component may also be directly coupled to an exposed metal segment along the length of a conductive yarn or monofilament. 
     Conductive and insulating strands may also be woven, knit, or otherwise intertwined to form conductive paths. The conductive paths may be used in forming signal paths (e.g., signal buses, 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. Conductive structures in fabric  12  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. 
     Item  10  may include additional mechanical structures  14  such as polymer binder to hold strands in fabric  12  together, support structures such as frame members, housing structures (e.g., an electronic device housing), and other mechanical structures. 
     Circuitry  16  may be included in item  10 . Circuitry  16  may include electrical components that are coupled to fabric  12 , electrical components that are housed within an enclosure formed by fabric  12 , electrical components that are attached to fabric  12  using welds, solder joints, adhesive bonds (e.g., conductive adhesive bonds such as anisotropic conductive adhesive bonds or other conductive adhesive bonds), crimped connections, or other electrical and/or mechanical bonds. Circuitry  16  may include metal structures for carrying current, electrical components such as integrated circuits, light-emitting diodes, sensors, controller circuitry for applying currents and/or magnetic fields to materials, electrically controlled devices for illuminating tubing and/or applying control signals to tubing or other strands, and other electrical devices. Control circuitry in circuitry  16  may be used to control the operation of item  10  by controlling electrically controllable (electrically adjustable) components in circuitry  16  and may be used to support communications with item  18  and/or other devices. 
     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 cover, case, bag, 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  (e.g., item  10  and item  18  may together form a fabric-based item such as a wristwatch with a strap). In still other situations, item  10  may be an electronic device (e.g., a wearable device such as a wrist device, clothing, etc.), fabric  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 yarns and monofilaments (e.g., insulated and bare wires) may be used to route signals in item  10  and/or item(s)  18 . 
     The fabric that makes up item  10  may be formed from strands that are intertwined using any suitable intertwining equipment. With one suitable arrangement, which may sometimes be described herein as an example, fabric  12  may be woven fabric formed using a weaving machine. In this type of illustrative configuration, fabric may have a plain weave, a basket 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. With other suitable arrangements, fabric  12  is knit or braided. 
     A cross-sectional side view of illustrative woven fabric  12  is shown in  FIG. 2 . As shown in  FIG. 2 , fabric  12  may include strands  20  such as warp strands  20 A and weft strands  20 B. In the illustrative configuration of  FIG. 2 , fabric  12  has a single layer of woven strands  20 . Multi-layer fabric constructions may be used for fabric  12  if desired. 
     As shown in  FIG. 3 , fabric  12  may be a knit fabric. In the illustrative configuration of  FIG. 3 , fabric  12  has a single layer of knit strands  20  that form horizontally extending rows of interlocking loops (courses  22 ) and vertically extending wales  24 . Other types of knit fabric may be used in item  10 , if desired. 
     Fabric-based item  10  may include non-fabric materials (e.g., structures such as structures  14  that are formed from plastic, metal, glass, ceramic, crystalline materials such as sapphire, etc.). These materials may be formed using molding operations, extrusion, machining, laser processing, and other fabrication techniques. In some configurations, some or all of fabric-based item  10  may include one or more layers of material. The layers in item  10  may include layers of polymer, metal, glass, fabric, adhesive, crystalline materials, ceramic, substrates on which components have been mounted, patterned layers of material, layers of material containing patterned metal traces, thin-film devices such as transistors, and/or other layers. 
       FIG. 4  is a diagram of illustrative equipment that may be used in forming fabric-based item  10 . Intertwining equipment such as tool  30  may include equipment such as braiding equipment, knitting equipment, and weaving equipment. Tool  30  may be used in forming fabric  12 , strands in fabric  12 , or other suitable intertwined strands. The strands formed by tool  30  may include strands with properties that vary along their lengths. For example, strands  20  may include strands having diameters that vary along the lengths of the strands or may include strands having material compositions or other properties that vary along the lengths of the strands. If desired, tool  30  may include sensors such as sensors  40 . Sensors  40  may monitor strands  20  during intertwining (e.g., when dispensing strands  20  into a weaving machine, into a knitting machining, into a braiding machine, etc.). For example, sensors  40  may monitor the optical properties of strands  20 , may monitor the diameter of strands  20 , may monitor for the presence of magnetic or conductive particles in strands  20 , and/or may otherwise monitor strands  20  along their lengths as strands  20  are being incorporated into fabric  12 . If desired, markers may be added to the strands during strand formation to assist sensors  40  in monitoring strands  20  during fabric formation. In this way, feedback adjustments may be made to tool  30  to ensure that desired portions of strands  20  are incorporated into desired locations in fabric  12 . 
     Cutting equipment such as trimming tool  34  (e.g., a mechanical cutting tool, a laser cutting tool, or other equipment for cutting yarn) may be used in cutting fabric  12 . For example, tool  34  may be used in cutting away undesired portions of fabric  12  and/or portions of strands in fabric  12 . 
     Heating tool  32  may be used in applying heat to tubing and other strands of material in fabric  12 . Heating tool  32  may include a laser for supplying heat, a reflow oven, an inductive heating tool for heating solder, a heat gun, a lamp, hot bar equipment, a soldering iron tip, equipment for forming heat by applying current (ohmic heating current) to a conductive strand, or may include other heating equipment. 
     Additional equipment such as equipment  36  may be used to help form fabric  12 , strands for fabric  12 , circuitry that is coupled to conductive structures in fabric  12 , electrical components, housing structures, and other structures for forming item  10 . Equipment  36  may, for example, include equipment for cutting fabric, equipment for laminating fabric to layers of plastic, metal, and/or other materials, equipment for mounting integrated circuits, light-emitting diodes, sensors, buttons, and other electrical circuitry to fabric  12  and/or other portions of item  10 , machining equipment for machining parts of item  10 , robotic assembly equipment, and/or other equipment for forming item  10 . The equipment of  FIG. 4  may be used to form fabric  12 , to process fabric  12 , to integrate circuitry  16 , fabric  12 , and/or additional structures  14  into item  10 , and/or to perform other fabrication and processing operations on item  10 . 
     Strands  20  may include strands of material that are uniform along their lengths and may include strands of material that are nonuniform along their lengths. Strands that vary along their lengths may be used to form fabric that has different properties in different areas. For example, optical properties such as optical transparency (opacity), reflectivity, and color may be varied along the lengths of a set of strands and, when these strands are incorporated into fabric  12 , fabric  12  may exhibit corresponding regions with different transparency values, different reflectivity values, and/or different colors. Mechanical properties may also be varied in strands  20  along their lengths. As an example, tensile strength, flexibility, surface roughness, porosity, hydrophobicity, strand diameter, stiffness, thermal conductivity, and/or other properties may be different at different portions along the length of a strand. Magnetic properties (e.g., the magnetic permeability and/or magnetization of strands  20 ), electrical properties (e.g., conductivity and radio-transparency, etc.), and/or other physical properties may also be varied along the length of each strand. 
     Illustrative strand fabrication equipment of the type that may be used in forming strands  20  with characteristics that vary as a function of length along the strands is shown in  FIG. 5 . Strand fabrication equipment  42 , which may sometimes be referred to as strand extruding equipment, may have a controller such as controller  44 . Controller  44  may issue commands to electrically controllable components using control signal paths such as paths  54  to vary the properties of strand  20  as strand  20  is extruded from extrusion nozzle  50  in extruder  48  and collected on wheel  56 . Wheel  56  may be rotated in direction  60  using motor  58 . The rate at which wheel  56  is rotated may be varied dynamically in response to control commands from controller  44  on path  54  (e.g., to thin strand  20  by pulling more rapidly on strand  20  or to thicken strand  20  by pulling less rapidly on strand  20 ). If desired, extruder  48  and nozzle  50  may be heated (e.g., to a temperature that is adjusted by controller  44 ). Material sources  46  may dispense adjustable amounts of material into extruder  48  (e.g., molten polymer and other liquids, gasses, powders made up of particles, wires, and/or other materials). There may be one or more sources  46  in equipment  42 , two or more sources  46  in equipment  42 , three or more sources  46  in equipment  42 , or other suitable numbers of sources  46  in equipment  42 . Each source may dispense a different respective material into extruder  48  as a function of time under the control of controller  44 . This allows controller  44  to dynamically vary the respective concentrations of each of the materials that make up strand  20 . 
     As an example, one of sources  46  may include a polymer (e.g., pellets of polymer that are melted in extruder  48 ) and another one of sources  46  may include a metal powder. The amount of metal powder that is incorporated into strand  20  as a function of length (and therefore properties such as the conductivity of strand  20  along its length) may be varied by adjusting the rate at which the metal powder is dispensed into extruder  48  relative to the rate at which the polymer is provided to extruder  48 . As another example, a first of sources  46  may include a first polymer, a second of sources  46  may include a second polymer, and a third of sources  46  may include a source of particles. The concentration of the particles and the relative concentrations of the first and second polymers can be dynamically adjusted by adjusting the sources. For example, in some portions of strand  20 , there may be more of the first polymer than the second polymer, so the properties of the first polymer will predominate and in other portions of strand  20  there may be more of the second polymer than the first polymer, so the properties of the second polymer will predominate. In one or both of these portions of strand  20 , the concentration of particles may be varied (e.g., to adjust physical properties, optical properties, electrical properties, magnetic properties, etc.). 
     As shown in  FIG. 5 , equipment  42  may include components  52  that modify strand  20  in response to control signals from controller  44 . Components  52  may include heating components that supply adjustable amounts of heat to strand  20 , light-emitting components that supply adjustable amounts of light to strand  20 , magnetic components (e.g., one or more electromagnets) that supply adjustable amounts of magnetic field to components  20 , mechanical tools (e.g., equipment for selectively roughening the surface of strand  20  using airborne particles, using a grinding wheel, embossing wheels, etc.), coating equipment (e.g., equipment for selectively spraying coatings onto strand  20 ), and/or other components for varying the properties of strand  20  as strand  20  is drawn out of nozzle  50  and onto wheel  56 . 
     Using equipment  42 , one or more characteristics of strand  20  may be varied along the length of strand  20 . As an example, the thickness (diameter) of strand  20  can be varied, the thermal conductivity of strand  20  can be varied, the surface roughness of strand  20  can be varied, the opacity, transparency, reflectivity, and color of strand  20  can be varied, the concentration of sensing agents (e.g., biological agents or chemical reagents that are configured to react with substances being sensed) can be varied, the stiffness (rigidity), the strength (e.g., compressive strength, tensile strength, wear resistance, etc.) of strand  20  can be varied, magnetic particle concentration can be varied to adjust magnetic permeability (e.g., the concentration with which particles such as iron particles or other magnetic particles are incorporated), the magnetization of strand  20  can be varied (e.g., whether magnetic material in strand  20  has random magnetic domains or has been magnetized by application of a magnetic field from an electromagnet in components  52 ), conductive particle concentration can be varied to alter the conductivity (e.g., the concentration of metal particles such as copper particles, and/or other conductive particles that are incorporated can be varied), the thickness and patterns of coatings can be varied (e.g., to create patterns of circumferential coating bands at particular locations along the lengths of strands  20 ), and/or other properties can be varied. If desired, particles such as nanoparticles (e.g., carbon nanotubes, quantum dots, etc.) may be incorporated into strands  20  and/or silicon integrated circuits or other integrated circuits may be incorporated into strands  20 . 
     In some configurations, controller  44  adjusts the relative feed rates for sources  46 , so that the composition of strand  20  is dynamically varied. In other configurations, the operation of strand-modifying devices such as components  52  can be dynamically varied. In general, adjustments to sources  46 , adjustments to components  52 , adjustments to nozzle  48 , and/or adjustments to strand pull rate (rotation rate for wheel  56 ) can be made. For example, the color of strand  20  can be varied by adjusting the concentration of dye that is incorporated into strand  20  from one of sources  46  and can be adjusted by varying the color of a coating that is applied to strand  20  by one of components  52 . As another example, strand stiffness may be varied by adjusting the relative concentrations of flexible and rigid polymers using sources  46  and strand conductivity can be varied by adjusting the amount of conductive coating applied to strand  20  by one of components  52 . 
     Strands  20  with properties that vary along their lengths may be intertwined to form fabric  12  using equipment  30 . As strands  20  are incorporated into fabric  12 , sensors  40  in equipment  30  may be used to monitor location-specific registration elements on strands  20  (e.g., marks, magnetic tags, conductive dots, and/or other markers that are incorporated into strands  20  to delineate the portions of strands  20  that have particular properties). This may enhance placement accuracy and thereby ensure that portions of strands  20  with desired properties are located precisely in desired locations in fabric  12 . In this way, fabric  12  may be formed that has different portions with different properties. As shown in  FIG. 6 , for example, fabric  12  may have a first portion such as portion  12 A that is formed from portions (segments) of strands  20  that have a first property, may have a second portion such as portion  12 B that is formed from segments of strands  20  that have a second property, and may have a third portion such as portion  12 C that is formed from segments of strands  20  that have a third property. Areas such as areas  12 A,  12 B, and  12 C may be discrete regions of fabric  12  and/or the properties of fabric  12  may be varied continuously as a function of location within fabric  12  (e.g., across dimensions X and/or Y in the example of  FIG. 6 ). 
       FIG. 7  is a diagram of an illustrative strand  20  with a characteristic that varies along its length. As shown in  FIG. 7 , strand  20  may extend along strand axis (longitudinal axis)  62 . One or more properties of strand  20  may vary in dimension  64  along the length of strand  20  (e.g., along axis  62 ). For example, strand  20  may have a first property in a region such as portion (segment)  20 - 1 , a second property in portion  20 - 2 , and may have a third property in portion  20 - 3 . Portions  20 - 1  and  20 - 3  may be, for example, circumferential bands of coating material (e.g., dye or metal) and portion  20 - 2  may be an uncovered portion of strand  20 . In another illustrative configuration, portions  20 - 1  and  20 - 3  may contain embedded particles (e.g., at different concentrations or at the same concentration) and portion  20 - 2  may be free of particles. Markers may be formed by arranging the portions of strands  20  that have different properties. 
     In general, strand properties may vary in steps (as shown in  FIG. 7 ) and/or may have continuously varying properties. For example, the stiffness of strand  20  may vary sinusoidally as a function of distance along dimension  64  (as one example).  FIG. 8  shows how the diameter of strand  20  may vary (e.g., the diameter of strand  20  of  FIG. 8  may be D1 in a first portion of strand  20 , may be D2 in a second portion of strand  20 , and may be D3 in a third portion of strand  20 . Configurations in which strand diameter is varied continuously may also be used. Strand diameter may be adjusted, for example, by varying the rate at which wheel  56  pulls (draws) strand  20  from nozzle  50 . Any suitable strand property or properties can be varied in this way.  FIG. 9  shows how strand  20  can be modified using a heating device (e.g., a heater in components  52  of  FIG. 5 ). Initially, strand  20  may include a core such as metal core  68  surrounded by coating  66  (e.g., a polymer coating), as shown in the upper portion of  FIG. 9 . Core  68  may, as an example, be formed form a low-melting-point solder. As shown in the lower portion of  FIG. 10 , when heat is selectively applied to a portion of solder core  68  (e.g., by inductive heating, by applying light or hot air, etc.), that portion of core  68  may melt and coalesce into spherical droplets that, when cooled, form individual metal spheres in the core of strand  20 . Electromagnets may be used to selectively magnetize portions of strand  20 , coating equipment (e.g., equipment for spraying on coatings or otherwise applying coatings to strand) may be used to selectively coat portions of strand  20 , and/or other adjustments may be made to strand  20  during the process of forming strand  20  with the equipment of  FIG. 5 . 
     By modulating the properties of strand  20  as strand  20  is formed, information may be encoded into strands  20 . As an example, markers can be incorporated into strands  20  that identify locations in strands  20  where the properties of strands  20  change (e.g., where strands  20  transition between a rigid material and a flexible material, where strands  20  changes color, where strands  20  transition between having a first type of embedded particle or first particle concentration and a second type of embedded particle and/or second particle concentration, where strand  20  change diameter, etc. The inclusion of markers may enhance placement accuracy by helping equipment  30  incorporate segments of strands  20  that have desired properties into desired areas of fabric  12 . Markers may be implemented using multi-element codes. For example, markers may be formed that have a particular number of bands of conductive material (e.g., three bands in a row or three bands separated with unequal spacing, etc.) or may be formed from a sequence of regions with embedded magnetic particles or conductive particles, etc. Markers may, if desired, signify the beginning of a portion of a strand with a particular property. Markers can be formed using one or more dyes or other materials detectable optical properties (e.g., one or more colors such as colors that are distinguishable from the native color of strand  20 ), magnetic particles and/or conductive particles of different sizes, permeability values, conductivities, and/or other measurable properties, mechanical marks (e.g., roughened bands), coating patterns (e.g., circumferential bands of metals, inks, etc. that can be optically detected or detected using magnetic sensors, electrical sensors, etc.), and/or other distinguishing local variations in the properties of strands  20  that serve as registration information. If desired, markers may be used to encode strands with other information (e.g., a batch number information, a strand identifier, or other information related to the source of a strand, the properties of a strand, the date of manufacture of a strand, etc.). 
     In the example of  FIG. 10 , item  10  is an electronic device with a housing formed from fabric  12  (or formed from fabric  12  and other materials such as plastic members, metal members, glass structures, ceramic housing portions, etc.). Circuitry (see, e.g., circuitry  16  of  FIG. 1 ) such as electrical components  72  may be mounted on one or more substrates such as printed circuit  70  in the interior of the housing formed from fabric  12 . The strands used in forming fabric  12  may have different properties at different locations along their lengths. 
     As described in connection with  FIG. 6 , fabric  12  may have different properties in different areas due to the varying properties of strands  20  along their lengths. For example, fabric  12  of  FIG. 10  may have different properties in region  12 W than in rear wall region  12 RW, sidewall regions  12 L and  12 R along the peripheral edges of device  10 , and front face region  12 F. In regions  12 L,  12 R,  12 RW, and  12 FW, for example, the portions of strands  10  that are present may contain metal particles and may therefore be conductive and not be radio-transparent. In region  12 W, the metal particles may be removed or may be reduced in quantity, so that strands  20  in this region are less conductive (e.g., insulating) and do not block radio-frequency wireless signals. In this way, region  12 W may form a radio-transparent window that allows components such as component  72  to transmit and receive wireless signals through region  12 W. Component  72  may include an antenna and other wireless communications circuitry that handles cellular telephone transmissions, wireless local area network transmissions, or other wireless communications. 
     As another example, region  12 W may be optically transparent at one or more wavelengths of interest, component  72  may be a light-based component such as a light-emitting diode or other light source for a status indicator light or other visible output devices, a light source and light detector that form an optical proximity sensor operating at infrared wavelengths or other suitable wavelengths, a flash for a camera, a camera or other digital image sensor device, a ambient light sensor, etc. Portions of fabric  12  may be clear, portions of fabric  12  may be opaque, and/or portions of fabric  12  may be translucent. Different areas may be colored differently and/or may have other distinct properties. 
     If desired, equipment may vary the density with which strands  20  are woven, knitted, or braided in different areas of fabric  12  or may otherwise locally change fabric  12  in different areas of fabric  12 . These techniques for altering the construction of fabric  12  in different areas may be used in conjunction with using strands that vary along their lengths to vary the properties of fabric  12  in different areas. 
     If desired, patterns in fabric  12  such as the pattern of region  12 W or other patterned areas of fabric  12  associated with distinct strand properties may be used in forming text, icons, key labels (e.g., alphanumeric characters or other key symbols, which may sometimes be referred to as glyphs), decorative trim, sensor electrodes (e.g., for a capacitive proximity sensor), and/or other patterns. These patterns may overlap fabric keys, portions of a removable case or other item in which an electronic device such as a cellular telephone, tablet computer, or other electronic device may be placed, portions of a wristwatch strap, etc. As an example, black portions of strands  20  (e.g., portions formed from black polymer) may be used in forming a fabric keyboard. Selected portions of these strands may be white (e.g., white polymer) and may be used in forming keyboard symbols (glyphs) for the keys in the keyboard. 
     Different areas of fabric  12  such as area  12 W and the other areas of  FIG. 10  may be provided with different stretch properties (e.g., by varying the relative concentration of elastomeric polymer relative to rigid polymer along the length of strands  20 ), may be provided with different porosities (e.g., more porous fabric may be formed from thinner and therefore less dense portions of strands  20 ), may be provided with different levels of coarseness (e.g., fabric  12  may be smooth except in region  12 W where fabric  12  is rough in texture), may be formed from strands with different optical properties (e.g., region  12 W may contain strand portions with particles or chemicals that are photoluminescent or electroluminescent whereas the other regions of fabric  12  may be free of these particles or chemicals), etc. 
     In the example of  FIG. 11 , the different properties of strands  20  at different locations along their lengths have been configured to reduce the melting temperature of fabric  12  in a particular location. For example, the melting point of fabric  12  may be lower in region  76  than in regions  74 . This may facilitate laser cutting of fabric  12  along line  78  in region  76  and/or may allow region  76  to be partly melted (e.g., to coalesce strands  20  in region  78 ) prior to laser or mechanical cutting in region  76 . 
       FIG. 12  is a cross-sectional side view of an illustrative sensor that may be formed using extrusion equipment  42  of  FIG. 5 . As shown in  FIG. 12 , strand  20  may have different diameters at different locations along its length. For example, strand  20  may have a smaller diameter in regions  20 N than in region  20 WD. A bubble such as gas bubble  84  may be incorporated into strand  20  by introducing a gas into strand  20  from a gas source among sources  46 . Strands of wire (e.g., bare or insulated metal wire such as copper wire) may be included in the core of strand  20 , as illustrated by wires  82 - 1  and  82 - 2 . These wires may be delivered into the interior of strands  20  during strand formation from respective sources  46  ( FIG. 5 ). 
     Dielectric material such as polymer  86  may be used in forming strand  20  of  FIG. 12 . Polymer  86 , which may be delivered from one of sources  46  may surround and separate wires  82 - 1  and  82 - 2  so that wires  82 - 1  and  82 - 2  do not direct contact each other and are not shorted to each other (e.g., at direct-current frequencies, wires  82 - 1  and  82 - 2  may be electrically isolated from each other). The capacitance between wires  82 - 1  and  82 - 2  may be measured using capacitance measurement circuitry in circuitry  16  that is coupled to wires  82 - 1  and  82 - 2 . When an external force (e.g., a squeezing force) is applied to opposing surfaces  88  of strand  20  in directions  90 , the portions of wires  82 - 1  and  82 - 2  in region  20 WD may be brought into close proximity to each other. This alters the capacitance between wires  82 - 1  and  82 - 2 . The capacitance measurement circuitry that is coupled to the wires can detect this change, so that control circuitry in item  10  can take appropriate action. For example, portion  20 WD of strand  20  may serve as a switch that a user of item  10  can use to change a media track during media playback operations, may serve as a switch to change a playback volume, may serve as an on-off switch, or may serve as any other suitable input device for item  10 . 
     If desired, custom clothes and other fabric-based items may be formed from strands  20 . For example, a user&#39;s body (e.g., a user&#39;s hands, feet, etc.) can be scanned using a three-dimensional scanning system and a computer-aided design system can construct custom clothing designs based on the measured shape of the user&#39;s body parts. Custom strands  20  and custom fabric  12  formed form the custom strands can then be created based on a custom design from the computer-aided design system. For example, based on a design that locates more dense areas of fabric  12  formed from tighter weaving and/or strands  20  of locally enhanced diameter over portions of the body where dense fabric is appropriate (e.g., where perspiration is less concentrated) and locating less dense areas formed from looser weaving and/or strands  20  of locally decreased diameter over portions of the body where less dense fabric is appropriate (e.g., where perspiration is more concentrated). 
     The foregoing is merely illustrative and various modifications can be made to the described embodiments. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20180330
Publication Date: 20190903
Grant Date: 20190903
Priority Date: 20170614
Inventors: KEATING, STEVEN J.
PODHAJNY, DANIEL A.
SUNSHINE, Daniel D.
CREWS, KATHRYN P.
Assignee: APPLE INC
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Family ID: 64657218