PATENT DOCUMENT

Publication Number: US-10191550-B1
Application Number: US-201715592049-A
Country: US
Kind Code: B1

Title: Fabric devices with shape memory alloy wires that provide haptic feedback

Abstract:
An electronic device may have haptic output devices based on shape memory alloy wire. The electronic device may have control circuitry that supplies current to the shape memory alloy wire to heat and thereby contract the shape memory wire to create vibrations for a user&#39;s finger. The vibrations may serve as haptic feedback in a device such as a keyboard, a strap with embedded buttons, or other electronic devices. The shape memory alloy wire may run between upper and lower fabric layers in a spacer fabric, may form loops that attached to a fabric layer, or may be tensioned across an opening in a printed circuit or other rigid support structure.

Claims:
What is claimed is: 
     
       1. An electronic device, comprising:
 a printed circuit board having at least one opening; 
 shape memory alloy wire that spans the opening and that has ends that are secured to the printed circuit board; 
 control circuitry that is configured to supply haptic output with the shape memory alloy wire by applying current to the shape memory alloy wire; and 
 fabric having conductive strands configured to carry the current to the shape memory alloy wire. 
 
     
     
       2. The electronic device defined in  claim 1  wherein the printed circuit has metal traces that are coupled to the shape memory alloy wire. 
     
     
       3. The electronic device defined in  claim 2  wherein the conductive strands are coupled to the metal traces. 
     
     
       4. The electronic device defined in  claim 3  wherein the conductive strands include a conductive warp strand and a conductive weft strand, wherein the printed circuit board has opposing first and second surfaces, wherein the conductive warp strand is coupled to a first portion of the metal traces on the first surface, and wherein the conductive weft strand is coupled to a second portion of the metal traces on the second surface. 
     
     
       5. The electronic device defined in  claim 4  wherein the shape memory alloy wire comprises a plurality of segments each of which spans the opening. 
     
     
       6. The electronic device defined in  claim 5  wherein the metal traces are configured to supply the current in series to the segments that span the opening. 
     
     
       7. The electronic device defined in  claim 1  wherein the shape memory alloy wire includes enlarged ends and wherein the printed circuit board has wire retention openings that receive the enlarged ends and that tension the shape memory alloy wire across the opening. 
     
     
       8. The electronic device defined in  claim 7  wherein the wire retention openings comprise notches in edges of the printed circuit board and wherein the printed circuit board comprises metal traces in the notches. 
     
     
       9. The electronic device defined in  claim 1  wherein the control circuitry is configured to gather signals from the shape memory alloy wire. 
     
     
       10. The electronic device defined in  claim 1  where the shape memory alloy wire has ends and wherein the printed circuit board has edges with recesses that receive the ends so that the shape memory alloy wire is tensioned across the opening. 
     
     
       11. The electronic device defined in  claim 10  further comprising metal retention pegs that secure the ends in the recesses. 
     
     
       12. A haptic output device that is controlled by current supplied by control circuitry, comprising:
 a layer of fabric having conductive strands; 
 a loop of shape memory alloy wire that receives the current, wherein the conductive strands are configured to carry the current to the loop of shape memory alloy wire; and 
 strands of material that are sewn into the layer of fabric and that tension the loop of shape memory alloy wire. 
 
     
     
       13. The haptic output device defined in  claim 12  wherein the loop of shape memory alloy has ends and wherein the ends are coupled to the conductive strands of material using laser-deposited molten metal droplets. 
     
     
       14. The haptic output device defined in  claim 12  wherein the conductive strands of material comprise conductive warp strands and conductive weft strands, wherein the loop of shape memory alloy has first and second ends, wherein one of the conductive warp strands is coupled to the first end, and wherein one of the conductive weft strands is coupled to the second end. 
     
     
       15. Apparatus, comprising:
 a first fabric layer; 
 a second fabric layer, wherein at least one of the first and second fabric layers comprises conductive strands; 
 undulating strands of material that pass between the first and second fabric layers and space the first and second fabric layers apart from each other; 
 an undulating shape memory alloy wire that passes between the first and second fabric layers and that is tensioned by the undulating strands of material; and 
 control circuitry configured to supply current to the undulating shape memory alloy wire to provide haptic output through the conductive strands. 
 
     
     
       16. The apparatus defined in  claim 15  wherein the first and second fabric layers comprise woven fabric layers. 
     
     
       17. The apparatus defined in  claim 16  wherein the undulating strands of material comprise polymer monofilaments.

Description:
This application claims the benefit of provisional patent application No. 62/334,827, filed May 11, 2016, which is hereby incorporated by reference herein in its entirety. 
    
    
     FIELD 
     This relates generally to electronic devices and, more particularly, to electronic devices with components that provide haptic output. 
     BACKGROUND 
     Devices such as keyboards may be incorporated into laptop computers and other equipment. Some keyboards have keys that click when pressed by a user. The clicks provided by the keys help alert a user when the keys have been pressed satisfactorily. Keys that are not pressed sufficiently will not click. 
     Mechanical clicking mechanisms may be used to provide this type of haptic feedback for a user of a keyboard, but mechanical clicking mechanisms may consume more space than desired. This may make it difficult or impossible to provide haptic feedback in a compact device such as a thin keyboard or other device in which space is at a premium. 
     SUMMARY 
     An electronic device may have haptic output devices based on shape memory alloy wire. The electronic device may have control circuitry that supplies current to the shape memory alloy wire to heat the wire and thereby contract the wire to create vibrations for a user&#39;s finger. The vibrations may serve as haptic feedback in a device such as a keyboard, a strap with embedded buttons, or other electronic devices. 
     The shape memory alloy wire may run between upper and lower fabric layers in a spacer fabric, may form loops that are sewn onto a fabric layer, or may be tensioned across an opening in a printed circuit or other rigid support structure. Conductive strands of material such as warp and weft fibers in a woven fabric may be coupled to the ends of a shape memory alloy wire. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of an illustrative electronic device in accordance with an embodiment. 
         FIG. 2  is a top view of illustrative fabric in accordance with an embodiment. 
         FIG. 3  is a diagram showing how a haptic device formed from shape memory alloy wire may be provided with current from control circuitry to heat and thereby constrict the wire in accordance with an embodiment. 
         FIG. 4  is a cross-sectional side view of an illustrative spacer fabric with shape memory alloy wire in an unexpanded configuration in accordance with an embodiment. 
         FIG. 5  is a cross-sectional side view of an illustrative spacer fabric with shape memory alloy wire in an expanded configuration in which the shape memory alloy wire is tensioned by an undulating spacer monofilament that runs between upper and lower fabric layers in accordance with an embodiment. 
         FIG. 6  is cross-sectional side view of an illustrative printed circuit board with a tapered opening that retains an enlarged end of a shape memory alloy wire in accordance with an embodiment. 
         FIG. 7  is a cross-sectional side view of an illustrative printed circuit board with a wire retention structure such as wire peg that helps hold the end of a shape memory alloy wire within an opening in the printed circuit board in accordance with an embodiment. 
         FIG. 8  is a top view of an illustrative printed circuit board with an opening spanned by tensioned shape memory alloy wires in accordance with an embodiment. 
         FIG. 9  is a portion of a printed circuit board with an illustrative arrangement that allows the printed circuit board to be compressed during attachment of a shape memory alloy wire to the printed circuit board so that the printed circuit board tensions the shape memory alloy wire when returned to its uncompressed state in accordance with an embodiment. 
         FIG. 10  is a top view of an illustrative loop of shape memory alloy wire that has been pulled outwardly by tensioning threads sewn into a fabric in accordance with an embodiment. 
         FIG. 11  is a cross-sectional side view of an illustrative shape memory alloy haptic device that is being used to gather user input in accordance with an embodiment. 
         FIG. 12  is a perspective view of an illustrative dome shaped structure that has been surrounded by loop of shape memory alloy wire to form a haptic output device in accordance with an embodiment. 
         FIG. 13  is a top view of an illustrative spiral shape memory alloy wire segment for a haptic device in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic devices may be provided with input-output devices. The input output devices may include devices that gather input from a user (e.g., touch sensors, buttons, force sensors, etc.) and devices that provide haptic feedback (e.g., tactile output in the form of vibrations that are picked up by a user&#39;s fingers). The haptic output devices may be separate from the input devices or may be configured to provide haptic feedback for associated input devices. As an example, a keyboard may have a capacitive touch sensor array integrated into a fabric layer that serves as an array of keys for gathering touch input (key presses) from a user. In this type of device, haptic devices may be used to provide haptic feedback to the user whenever a user presses one of the keys (i.e., a vibration for a button click or other haptic feedback may be provided whenever a key input is detected to help inform the user that the user has successfully completed the key input). Haptic devices may be formed from shape memory alloy structures such as lengths of shape memory alloy wire. 
     A schematic diagram of an illustrative electronic device of the type that may include haptic devices such as haptic devices based on shape memory alloy wire is shown in  FIG. 1 . Electronic device  10  of  FIG. 1  may be 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 wristwatch device, a pendant device, a headphone or earpiece device, a device embedded in eyeglasses or other equipment worn on a user&#39;s head, or other wearable or miniature device, a television, a computer display that does not contain an embedded computer, a gaming device, a navigation device, an embedded system such as a system in which electronic device  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, electronic device  10  may be a removable external case for electronic equipment or other device accessory, may be a strap, may be a wrist band or head band, may be a removable cover for a device, may be a case or bag that has straps or that has other structures to receive and carry electronic equipment and other items, may be a necklace or arm band, may be a wallet, sleeve, pocket, or other structure into which electronic equipment or other items may be inserted, may be part of a chair, sofa, or other seating (e.g., cushions or other seating structures), may be part of an item of clothing or other wearable item (e.g., a hat, belt, wrist band, headband, shirt, pants, shoes, etc.), may be a keyboard, or may be any other suitable device that includes circuitry. 
     As shown in  FIG. 1 , electronic device  10  may have control circuitry  12 . Control circuitry  12  may include storage and processing circuitry for supporting the operation of device  10 . The storage and processing circuitry may include storage such as hard disk drive storage, nonvolatile memory (e.g., flash memory or other electrically-programmable-read-only memory configured to form a solid state drive), volatile memory (e.g., static or dynamic random-access-memory), etc. Processing circuitry in control circuitry  12  may be used to control the operation of device  10 . The processing circuitry may be based on one or more microprocessors, microcontrollers, digital signal processors, baseband processors, power management units, audio chips, application specific integrated circuits, etc. 
     Input-output circuitry in device  10  such as input-output devices  14  may be used to allow data to be supplied to device  10  and to allow data to be provided from device  10  to external devices. Input-output devices  14  may include buttons, joysticks, scrolling wheels, touch pads, key pads, keyboards, microphones, speakers, tone generators, vibrators, cameras, sensors, light-emitting diodes and other status indicators, displays, data ports, etc. Input-output devices  14  may include haptic devices  16  such as haptic devices based on shape memory alloys (e.g., nickel-titanium or other alloys). Shape memory alloys exhibit a phase change (between austenite and martensite for nickel-titanium) upon heating and cooling. As a result, shape memory alloys can be made to contract when heated with an applied current and can be allowed to relax to an uncontracted state when cooled by removing the applied current. These shape memory alloy properties allow electronically controlled haptic output devices to be formed from lengths of shape memory alloy wire. 
     Control circuitry  12  may be used to run software on device  10  such as operating system code and applications. During operation of device  10 , the software running on control circuitry  12  may use input-output devices  14  to gather user input (e.g., key press input or other input from a keyboard, button press input from a button on a fabric wrist band or other fabric item, or other input from input-output devices  14 ) and to supply the user with output using input-output devices  14 . Device  10  may, for example, supply a user with haptic output using haptic devices  16  (e.g., haptic feedback to inform a user that a key in a keyboard, a button on a watch band, or other input device has been received). Input-output devices may, if desired, include shape memory alloy wire actuators for providing vibrating alerts (haptic alerts) and other haptic output (i.e., haptic output that is not necessarily directly related to confirming a key press or button press). In general, shape memory alloy devices may be used for forming any suitable actuators. The use of shape memory alloy wire to form haptic devices such as devices that provide a user with haptic feedback while the user is supplying a keyboard or other input device with input is sometimes described herein as an example. 
     Device  10  may include fabric. Fabric may be used to form a housing structure, part of a strap or band, a cover for a keyboard, or other structures in device  10 . Fabric may be knitted, braided, woven, or otherwise formed from intertwined fibers. As an example, the fabric for device  10  may include woven fabric such as illustrative woven fabric  18  of  FIG. 2 . As shown in  FIG. 2 , fabric  18  may include strands of material such as warp strands  20  and perpendicular strand of material such as weft strands  22 . Fabric  18  may have a plain weave, a basket weave, may be a three-dimensional fabric (e.g., a spacer fabric), or may have other suitable fabric constructions. Strands  20  and  22  may include insulating strands and/or conductive strands. Conductive strands may be formed from metal wires, metal wires coated with polymer, metal coatings on insulating strands of material such as glass or polymer strands, or other suitable conductive structures. Insulating strands may be formed from polymer, other dielectric, multiple dielectric layers, or other suitable insulating structures. Strands of material in fabric  18  may be monofilaments or may be multifilament yarns. Fabric  18  may include exclusively insulating strands, may include exclusively conductive strands, or may include a mixture of insulating and conductive strands. For example, fabric  18  may include insulating strands and conductive strands and the conductive strands may be used in carrying signals associated with input-output devices  14  (e.g., currents for controlling haptic devices  16 , sensor signals, etc.). 
     As shown in  FIG. 3 , a shape memory alloy wire such as wire  24  may receive a control signal from control circuitry  12  such as current I. When current I is applied to wire  24 , wire  24  will be heated by ohmic heating. When wire  24  is heated in this way, wire  24  will contract in directions  26 . By forming wire  24  into appropriate shapes within fabric  18  or other structures in device  10 , haptic feedback devices such as devices  16  may be formed. Wire  24  (and, if desired, other strands in fabric  18 ) may have a diameter of 20-40 microns, more than 5 microns, less than 100 microns, or other suitable diameter. These relatively small diameters allow wire  24  to be incorporated into fabric  18  even in configurations in which fabric  18  is soft and flexible. Wire  24  may also be incorporated into rigid fabric. 
     Wire  24  may be used to form haptic devices in which wire  24  is bent (e.g., in which wire  24  undulates back and forth), may be used to form haptic devices in which wire  24  is stressed in torsion (e.g., configurations in which wire  24  is coiled into the shape of a spring), and may be used to form haptic devices in which wire  24  is tensioned along its length. Configuration in which wire  24  is tensioned along its length may be used in applications in which it is desired to conserve power, because tensioned shape memory alloy wire configurations tend to be more efficient at creating haptic output than torsion and bending configurations. In general, however, any suitable arrangement may be used in forming haptic devices  16  (e.g., bending, torsion, or tension). 
     If desired, wire  24  for haptic device  16  may be incorporated into a three-dimensional fabric such as a spacer fabric.  FIGS. 4 and 5  illustrate how wire  24  may be incorporated into spacer fabric and placed under tension. As shown in  FIG. 4 , spacer strands such as spacer strand  32  may run between two layers of fabric such as fabric layers  30 T and  30 B. Strand  32  may be, for example, a polymer monofilament. Wire  24  may also run between layers  30 T and  30 B. Fabric layers  30 T and  30 B may be woven fabric layers or other fabric and may be stretched laterally outwards while incorporating strands  32  and wires  24 . Strand  32  may pass back and forth between layers  30 T and  30 B with a first undulation frequency. Wire  24  may pass back and forth between layers  30 T and  30 B with a second undulation frequency that is different than the first frequency (e.g., a second undulation frequency that is higher than the first frequency). When layers  30 T and  30 B are released (i.e., when layers  30 T and  30 B are no longer being stretched outwards), layers  30 T and  30 B will retract inwardly in directions  34 , as shown in  FIG. 5 . This reduces the lateral spacing between the undulations in spacer strands  32 . The lateral spacing reduction in the undulations of spacer strands  32  forces layers  30 T and  30 B apart in directions  36  and tensions wire  24 . Wire  24  of  FIG. 5  may be used to form one or more haptic output devices  16 . When it is desired to provide haptic output, current may be applied to wire  24  to produce vibrations. Current may be supplied to wire  24  using conductive warp and weft fibers in fabric layers such as layers  30 T and  30 B (see, e.g., fabric  18  of  FIG. 2 ) or other signal paths. The resistivity of the conductive warp and weft strands or other signal paths being used to supply current to wire  24  is preferably less than the resistivity of wire  24 , so that ohmic heating is concentrated within wire  24  and not the signal lines feeding wire  24 . 
     If desired, wire  24  may be tensioned using a rigid printed circuit board substrate or other rigid support structure. Wire  24  may, for example, be provided in segments that have opposing ends. Each end of each wire segment may be anchored to a portion of the rigid support structure. In general, the ends of wire  24  (or points midway along the length of wire  24 ) may be anchored to a printed circuit board using any suitable anchoring mechanisms (welds, crimps, anchoring holes, solder, adhesive, screws or other fasteners, brackets, etc.). 
     With one illustrative arrangement, which is illustrated in the cross-sectional side view of  FIG. 6 , wire  24  may have enlarged ends such as end  24 E. Enlarged end  24 E may be formed by crimping, laser processing, wire bonding equipment, or other equipment for forming an enlarged end on wire  24 . Printed circuit board  38  may have wire retention openings (e.g., a tapered opening of the type shown in  FIG. 6 ) to receives enlarged ends such as enlarged end  24 E. Wire  24  is placed under tension, so each enlarged end  24 E is pulled up into a respective wire end retention opening in printed circuit board  38 . Due to the relatively small size of the hole at the upper end of the tapered opening, enlarged end  24 E is trapped in the tapered opening and presses against metal traces such as metal sidewall contacts  42 T in the opening. Other metal traces (e.g., traces  42 ) in printed circuit  38  may be used to couple wire  24  to pads or other contacts on printed circuit  28  and/or other circuitry mounted on printed circuit  38 . With this type of configuration, each end  24 E of wire  24  may be secured in an opening in printed circuit  38 . With the ends of wire  24  secured in this way, wire  24  may be maintained under tension, thereby allowing wire  24  to form an efficient haptic output device  16 . 
       FIG. 7  shows how a peg or other securing structure (see, e.g., metal wire retention peg  44 ) may be used in securing end  24 E of wire  24  in a wire end retention opening in printed circuit  38  (e.g., so that wire end  24 E electrically connects to metal traces such as traces  42 ). Wire  24  of  FIG. 7  may be held in tension (e.g., by stretching wire  24  in direction  46  after end  24 E has been secured to printed circuit board  38  using peg  44  or other suitable attachment structure). 
       FIG. 8  is a top view of an illustrative haptic output device formed by stretching multiple lengths of wire  24  across an opening in a printed circuit board. As shown in  FIG. 8 , printed circuit board  38  may have an opening such as opening  52 . Opening  52  may have a size and shape appropriate for forming a keyboard key (i.e., opening  52  may have the size of a user&#39;s fingertip). A fabric covering (e.g., fabric  18 ) or other flexible covering layer with an alphanumeric label (e.g., a key symbol) may overlap printed circuit  38  and opening  52 . Printed circuit substrate  38  may have wire retention openings for securing the ends of wires  24 . As an example, printed circuit substrate  38  may have recesses such as notches  50  along opposing edges of substrate  38  that receive wire  24 . Ends  24 E of wires  24  may be enlarged so that ends  24  catch in notches  50 . This allows wires  24  to be stretched across opening  52  and held in tension. 
     Metal traces  42  (including contacts  42 T for contacting ends  24 E of wires  24 ) may be used to couple together multiple segments of wire  24  in series as shown in  FIG. 8  or may be used to couple wire segments in parallel or other suitable configurations. Current may be supplied to shape memory alloy wire  24  of  FIG. 8  using any suitable signal paths. In the example of  FIG. 8 , metal traces in printed circuit  38  such contact pads  42 P formed respectively on the lower and upper surfaces of printed circuit  38  may be coupled to conductive warp strand  20  and conductive weft strand  22 , respectively using conductive material  48 . Conductive material  48  may be solder, metal deposited using a laser, melted metal created during laser welding, or other suitable conductive material. An array of printed circuit haptic devices such as the device of  FIG. 8  may be used to form a keyboard or other input device or a larger printed circuit may be provided with an array of openings  52  each of which is spanned by wire  24 . 
     When it is desired to activate the haptic device formed from the structures of  FIG. 8 , control circuitry  12  may supply current to wire  24  through strands  20  and  22 . Wire  24  may be tensioned by stretching wire  24  across opening  52  and, if desired, may be further tensioned when a user presses downwardly on strands  52  (i.e., in direction—Z of  FIG. 8 ) as part of a key press operation. Wire  24  may form part of an input device for device  10  (e.g., a capacitive touch sensor, force sensor, switch, etc.) or wire  24  and opening  52  may be mounted in alignment with a separate input device (e.g., a light-based proximity sensor, a switch, a capacitive touch sensor, etc.). 
       FIG. 9  shows how a printed circuit substrate or other substrate may be compressed during attachment of wire  24 . When compressed, the illustrative L-shaped printed circuit substrate of  FIG. 9  may assume compressed shape  38 L′. While the substrate is in this configuration, the ends of a length of shape memory alloy wire  24  may be attached to notches  50  (see, e.g., wire segment  24 - 1 ). The substrate can then be released. Due to the elastic nature of the substrate, the substrate will spring back to uncompressed shape  38 L. This tensions the shape memory alloy wire (see, e.g., tensioned wire segment  24 - 2 ). If desired, rectangular printed circuit board substrates of the type shown in  FIG. 8  (e.g., rectangular ring-shaped substrates) may likewise be compressed while segments of wire  24  are being attached to notches  50 . The L-shaped substrate of  FIG. 9  is shown as an example. 
     In the illustrative arrangement of  FIG. 10 , shape memory alloy wire  24  has been mounted on fabric  18 . Sewn (embroidered) yarn such as strands  56  may have a zigzag pattern or other pattern with segments that pull wire  24  outwardly in directions  58 , thereby tensioning wire  24 . The ends of wire  24  may be coupled to exposed portions of warp strand  20  (see, e.g., exposed warp strand segment  20 ′) and weft strand  22  (see, e.g., exposed weft strand segment  22 ′) or the ends of the loop of wire  24  of  FIG. 10  may otherwise be coupled to signal lines that can route control signals to wire  24  from control circuitry  12 . When current is applied to wire  24 , wire  24  will contract and cause a portion of fabric  18  such as the portion of fabric  18  within the wire loop of  FIG. 10  to protrude (e.g., upward in direction Z in  FIG. 10 ) to serve as haptic output for a user&#39;s finger that is in contact with that portion of fabric  18 . 
     Conductive connections between the ends of wire  24  and conductive warp and weft strands in fabric  18  may be formed using any suitable technique. The conductive connections may, for example, be formed by laser welding or other welding techniques, by soldering, by crimping, using clips or other fasteners, or using other suitable techniques. With one illustrative arrangement, sometimes referred to as a laser induced forward transfer technique, a metal donor layer is formed on the underside of a transparent substrate such as a glass substrate. Pulses of laser light are applied to the metal donor layer through the transparent substrate. The laser light pulses cause molten droplets of the metal of the donor layer to be deposited onto a desired target. This technique may be used to form a conductive connection between wire  24  and conductive warp or weft strands in fabric  18  (i.e., a metal joint may be laser deposited over the ends of wire  24  at exposed warp strand portion  20 ′ and exposed weft strand portion  22 ′). Other techniques may be used in forming conductive connections between wire  24  and conductive strands such as strands  20  and  22  that supply signals to wire  24 , if desired. These techniques may also be used in forming connections with pads  42 P or other printed circuit board traces in printed circuit boards such as printed circuit board  38  of  FIG. 8 . The resistivity of the conductive warp and weft strands or other signal paths being used to supply current to wire  24  is preferably less than the resistivity of wire  24 , so that ohmic heating is concentrated within wire  24  and not the signal lines feeding wire  24 . 
     If desired, wire  24  and other conductive strands of material (in fabric  18 , coupled to printed circuit  38 , etc.) may be used in forming sensors. Consider, as an example, the haptic feedback arrangement of  FIG. 11 . In the example of  FIG. 11 , support structure  74  (e.g., a printed circuit such as printed circuit  38  of  FIG. 8 , fabric such as fabric  18 , or other structure) has been provided with a signal path such as path  72 . Path  72  may be formed from a conductive warp or weft strand in a fabric layer, may be formed from a metal trace on a printed circuit, may be formed from shape memory alloy wire, or may be formed from other conductive structure. Shape memory alloy wire  24  may overlap at least part of path  72 . When a user&#39;s finger such as finger  70  rests against wire  24 , control circuitry  12  may supply current to wire  24  to heat and thereby contract wire  24 . In this way, wire  24  may be used as a haptic output device. At the same time, control circuitry  12  may monitor the structures of  FIG. 11  for input (i.e., the structures of  FIG. 11  may serve both as a haptic output device and as an input device). 
     Downward pressure from finger  70  may cause wire  24  to move towards path  72 . Control circuitry  12  may monitor the conductive paths in  FIG. 11  for input using any suitable monitoring technique. 
     With one illustrative arrangement, control circuitry  12  monitors the resistance between wire  24  and path  72 . In this type of arrangement, wire  24  and path  72  serve as switch terminals and control circuitry  12  determines whether wire  24  and path  72  are contacting each other and forming a short circuit (forming a closed switch state) or are separated from each other and are forming an open circuit (forming an open switch state). 
     With another illustrative arrangement, control circuitry  12  measures the capacitance between wire  24  and path  72 . In this configuration, wire  24  and path  72  serve as capacitor electrodes in a capacitive sensor. The amount that wire  24  is pressed downwards by finger  70  affects the separation between wire  24  and path  74  and therefore gives rise to an associated capacitance value between wire  24  and path  74 . Control circuitry  12  may convert capacitance measurements into force values (i.e., the structures of  FIG. 11  may be operated as a capacitive force sensor) or may convert capacitance measurements into binary output (i.e., the structures of  FIG. 11  may be used as a capacitive touch sensor switch in which the presence of a finger is detected or not detected by comparing capacitance measurements to a predetermined threshold). 
     Other types of capacitance measurements, resistive measurements, and/or other signal measurements may be made on conductive structures formed from shape memory alloy wire  24  and/or other metal structures such as wires  20  and/or  22 , etc., if desired. For example, a grid of overlapping conductive warp and weft strands may be used in forming a capacitive touch sensor and an array of haptic devices formed from memory alloy wire  24  may overlap this grid. The capacitive touch sensor grid may be used to gather touch input from a user&#39;s finger (e.g., the capacitive touch sensor grid may operate as a track pad and/or keyboard) and the haptic devices formed from memory alloy wire  24  may provide haptic feedback as the user is providing input (i.e., there may be a haptic feedback device formed from shape memory alloy wire  24  for each key in the keyboard, etc.). 
     If desired, shape memory alloy wire  24  may be looped around a dome structure such as illustrative dome  76  of  FIG. 12 . Dome  76  may be formed from a flexible material such as silicone or other elastomeric polymer, may be formed from a flexible material such as fabric, or may be formed from other suitable structures. Dome  76  may be mounted to a printed circuit substrate, to a fabric substrate such as fabric  18  of  FIG. 12 , or other suitable support structure. If desired, dome  76  may be a fabric dome that is formed as an integral portion of a fabric layer such as fabric layer  18  of  FIG. 12 . Shape memory alloy wire  24  may have a loop shape that runs along the circular periphery of dome  76 . When current is applied to wire  24 , wire  24  will contract and thereby cause dome  76  to protrude upward. If a user&#39;s finger is in contact with dome  76  (directly or through a layer of fabric or other material overlapping dome  76 ), the user will be provided with haptic output as a result of the upward movement of dome  76 . If desired, an input device may be incorporated into a dome-based haptic device (e.g., dome  76  may be a dome switch for detecting finger presses, etc.). 
       FIG. 13  is a top view of an illustrative spiral segment of shape memory alloy wire  24  that has been used to form a haptic output device on fabric  18 . Wire  24  may be held in place using embroidery (e.g., yarn or other strands of material that are sewn into fabric  18 ) or may be secured using adhesive, welds, solder, fasteners, etc. There are more loops of wire  24  in a spiral shaped haptic device than in a haptic device based on a single loop of wire  24 , which may help increase the amount of haptic output that is produced. If desired, loops of wire  24  may have non-spiral circular shapes with multiple loops (i.e., each of the turns of a multi-turn loop may have substantially the same diameter). Configurations in which wire  24  has both multiple concentric circular turns and an inner spiral portion may also be used in forming haptic devices  16 . The spiral shape of wire  24  in  FIG. 13  is merely illustrative. 
     Haptic devices  16  may be aligned with input devices such as switches (e.g., dome switches), capacitive touch sensors, capacitive force sensors, optical sensors (e.g., light-based proximity sensors each having a light emitter and a light detector for measuring scattered light that has been emitted by the light emitter), force or touch sensors based on changes in resistance of fabric, foam, or other materials, piezoelectric sensors, or other input devices. Haptic devices may be used to supply vibrating output to alert a user to the occurrence of particular events and/or may supply vibrating output in response to detection of a user input event (e.g., a key press, button press, or other input in which the user touches and/or applies force to an input device). Haptic devices and associated input devices such as keys (buttons) may, for example, be provided in a keyboard array to form a keyboard, may be arranged in a row or other pattern on a fabric watch band, may be formed in an array or other pattern on the sleeve or pocket of an item of clothing, etc. If desired, shape memory alloy wire  24  may be used to apply force to a user&#39;s finger, arm, or other body part (e.g., to serve as a blood pressure measurement arm cuff, to provide haptic feedback to a finger in a glove, etc.). In configurations such as these, loops of shape memory wire  24  may be incorporated into fabric or other material and may surround a user&#39;s arm, finger, etc. For example, loops of wire  24  may be used to surround fingers in a fabric glove to provide a user&#39;s fingers with haptic feedback when the user is wearing the glove. 
     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: 20170510
Publication Date: 20190129
Grant Date: 20190129
Priority Date: 20160511
Inventors: NUSSBAUM, MICHAEL B.
BEESLEY, MARK J.
SUNSHINE, Daniel D.
SCHULTZ, CHRISTOPHER A.
PODHAJNY, DANIEL A.
Assignee: APPLE INC
CPC Classifications: [{"code": "G06F3/016", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/044", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0447", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0446", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0445", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F2203/04105", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/016", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/0446", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F2203/04105", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/016", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/0445", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 65032079