PATENT DOCUMENT

Publication Number: US-10732728-B1
Application Number: US-201715467986-A
Country: US
Kind Code: B1

Title: Keyboard with touch sensor

Abstract:
A keyboard may be provided that has keys overlapped by a touch sensor. The keyboard may have key sensor circuitry for monitoring switching in the keys for key press input. The keyboard may also have touch sensor circuitry such as capacitive touch sensor circuitry that monitors capacitive electrodes in the touch sensor for touch sensor input such as multitouch gesture input. The touch sensor may be formed from a layer of fabric. The fabric may be woven fabric or other fabric in which conductive strands of material serve as the electrodes for the touch sensor.

Claims:
What is claimed is: 
     
       1. A keyboard having an interior and an exterior, the keyboard comprising:
 a substrate; 
 an array of switches mounted on the substrate; 
 an array of movable key members each of which overlaps a respective one of the switches to form a corresponding key; and 
 a fabric touch sensor that overlaps the movable key members, wherein the fabric touch sensor comprises conductive strands that form drive lines and sense lines, wherein the movable key members are interposed between the array of switches and the fabric touch sensor, wherein the fabric touch sensor is exposed to the exterior, wherein the fabric touch sensor is separated from the substrate by a first distance in a first region that overlaps a movable key member, wherein the fabric touch sensor is separated from the substrate by a second distance in a second region between adjacent movable key members, and wherein the first distance and the second distance are different. 
 
     
     
       2. The keyboard defined in  claim 1  further comprising:
 control circuitry that is coupled to the switches and that is configured to monitor for key presses that close the switches. 
 
     
     
       3. The keyboard defined in  claim 2  wherein the control circuitry is coupled to the conductive strands in the fabric touch sensor and that is configured to gather touch input from the conductive strands. 
     
     
       4. The keyboard defined in  claim 3  wherein the conductive strands include a first set of conductive strands that run across the keys along a first dimension and a second set of conductive strands that run across the keys along a second dimension that is perpendicular to the first dimension. 
     
     
       5. The keyboard defined in  claim 4  wherein each of the conductive strands include at least one wire coated with polymer. 
     
     
       6. The keyboard defined in  claim 5  wherein the wire comprises copper wire. 
     
     
       7. The keyboard defined in  claim 6  wherein the keys comprise alphanumeric keys that have a QWERTY layout. 
     
     
       8. The keyboard defined in  claim 3  wherein the fabric comprises woven fabric, wherein the conductive strands comprise conductive warp strand and conductive weft strands, and wherein the fabric comprises insulating warp strands and insulating weft strands. 
     
     
       9. The keyboard defined in  claim 3  wherein the switches comprise dome switches. 
     
     
       10. The keyboard defined in  claim 9  further comprising metal traces on the substrate that couple the switches to the control circuitry. 
     
     
       11. The keyboard defined in  claim 3  wherein the fabric touch sensor comprises woven fabric that includes the conductive strands. 
     
     
       12. The keyboard defined in  claim 11  further comprising a layer of adhesive that attaches the woven fabric to the movable key members. 
     
     
       13. The keyboard defined in  claim 3  wherein the control circuitry includes capacitive touch sensor circuitry that gathers the touch input from the conductive strands. 
     
     
       14. The keyboard defined in  claim 13  wherein each of the conductive strands comprises at least one copper wire with a polymer coating. 
     
     
       15. The keyboard defined in  claim 1  wherein the switches each have a height that is less than the first distance and less than the second distance. 
     
     
       16. Apparatus, comprising:
 at least one key having a movable key member that is configured to close a switch in response to pressure applied to the movable key member; 
 an inner fabric layer comprising a grid of conductive lines that form a capacitive touch sensor that overlaps the key, wherein the inner fabric layer conforms to a raised surface of the movable key member; and 
 an outer fabric layer that overlaps the grid of conductive lines and that is coupled to the inner fabric layer with an adhesive, wherein the adhesive overlaps the movable key member. 
 
     
     
       17. The apparatus defined in  claim 16  wherein the inner fabric layer comprises woven fabric that includes insulating strands and conductive strands, wherein the grid of conductive lines comprises drive lines and sense lines that detect multitouch gesture input, and wherein the conductive strands form the drive lines and the sense lines in the grid of conductive lines. 
     
     
       18. The apparatus defined in  claim 17  wherein the conductive strands comprise copper wires with polymer coatings. 
     
     
       19. A device, comprising:
 a plurality of keys, wherein each of the keys has a movable key cap with a raised surface and an associated switch that is closed when pressed by the movable key cap in response to pressure on the movable key cap; 
 key sensor circuitry that monitors the keys for key press events; 
 a fabric layer that overlaps and conforms to the raised surfaces of the movable key caps of the plurality of keys, wherein the fabric layer has insulating strands of material and has conductive warp and weft strands that are intertwined with the insulating strands and wherein each of the movable key caps is between the switch associated with that movable key cap and the fabric layer; 
 a force sensor formed in addition to the plurality of keys, wherein the force sensor detects a force based on a change in capacitance between the conductive warp and weft strands and a conductive structure overlapped by the fabric layer; and 
 capacitive touch sensor circuitry that is coupled to the conductive warp and weft strands and that gathers multitouch gesture input from the conductive warp and weft strands. 
 
     
     
       20. The device defined in  claim 19  wherein the movable key caps comprise plastic movable key caps.

Description:
This application claims the benefit of provisional patent application No. 62/331,892, filed May 4, 2016, which is hereby incorporated by reference herein in its entirety. 
    
    
     FIELD 
     This relates generally to electronic devices such as keyboards and, more particularly, to devices such as keyboards with touch sensor functionality. 
     BACKGROUND 
     Keyboards may be incorporated into laptop computers and may be used as accessories for electronic devices such as tablet computers and other devices. 
     Some keyboards have trackpads to allow a user to supply touch input. Due to space considerations and other constraints, it can be difficult or impossible to provide desired touch sensor functionality to components such as keyboards. 
     SUMMARY 
     A keyboard may have keys that are overlapped by a touch sensor. The keys may be pressed by a user and the touch sensor may be used to supply touch input. 
     Key sensor circuitry in the keyboard may be coupled to switches in the keys using traces on a printed circuit or other substrate. The switches may be mounted to the substrate under movable key members. During operation, the key sensor circuitry may monitor the switches to determine when the keys are being pressed by the user. 
     The keyboard may also have touch sensor circuitry. The touch sensor circuitry may be capacitive touch sensor circuitry that monitors capacitive electrodes in the touch sensor for touch input from the user. The touch sensor may be a fabric touch sensor that is formed from a layer of fabric. The fabric may be woven fabric or other fabric in which conductive strands of material serve as the electrodes. The conductive strands may be copper wires coated with polymer or other conductive strands of material. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of an illustrative electronic device and associated keyboards in accordance with an embodiment. 
         FIG. 2  is a perspective view of a portion of a keyboard in accordance with an embodiment. 
         FIG. 3  is a cross-sectional side view of an illustrative key in a keyboard in accordance with an embodiment. 
         FIG. 4  is a cross-sectional side view of an illustrative keyboard key that has a scissor mechanism in accordance with an embodiment. 
         FIG. 5  is a cross-sectional side view of an illustrative keyboard that has a key support structure with an array of openings that receive movable key members in accordance with an embodiment. 
         FIG. 6  is a circuit diagram of an illustrative keyboard with keys and an overlapping grid of touch sensor electrodes in a capacitive touch sensor in accordance with an embodiment. 
         FIG. 7  is a top view of an illustrative fabric for a keyboard in accordance with an embodiment. 
         FIGS. 8 and 9  are cross-sectional side views of illustrative layers of fabric in accordance with embodiments. 
         FIGS. 10 and 11  are cross-sectional side views of illustrative keyboard keys in accordance with embodiments. 
         FIG. 12  is a cross-sectional side view of an illustrative fabric showing where conductive strands of material may be located relative to insulating strands of material in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     A keyboard may be provided with keys to receive keypress input from a user and may be provided with overlapping touch sensor circuitry to receive touch input from a user. An illustrative system of the type that may include keyboards is shown in  FIG. 1 . The system of  FIG. 1  may include an electronic device such as electronic device  10 . Device  10  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.), or may be any other suitable device that includes circuitry. 
     Keyboards  12  may be used to gather input from a user. As shown in  FIG. 1 , keyboards  12  may be incorporated into electronic devices such as device  10  or may be coupled to electronic devices such as device  10  via a path such as path  14 . Path  14  may be a wired or wireless path. Configurations in which device  10  includes an embedded keyboard  12  and is also coupled to a stand-alone external keyboard  12  by path  14  may be used, if desired. 
       FIG. 2  is a perspective view of a portion of keyboard  12 . As shown in  FIG. 2 , keyboard  12  may have an array of keys  14 . Keys  14  may be pressed by a user to supply keyboard  12  with keypress input (keypress events). Keys  14  may be alphanumeric keys, may be keys labeled with text (e.g., “backspace,” “shift,” etc.), may serve as function keys, may include special-function keys (e.g., keys to alter the magnification of on-screen content, keys for placing a device in a sleep mode, etc.), may be single-function or multi-function buttons, may be alphanumeric keys arranged in a QWERTY format, may be arranged in rows and columns or other patterns, may be configured to form other types of keyboard devices (e.g., numeric keypads, etc.), or may be any other suitable keys. 
     A cross-sectional side view of an illustrative key in keyboard  12  is shown in  FIG. 3 . As shown in  FIG. 3 , a user&#39;s finger (finger  16 ) or other external object may be used to press down (inwardly) on key  14  in direction  20 . Key  14  may have a movable key member such as movable key member  24  (sometimes referred to as a key cap). When pressed in direction  20 , key member  24  may move in direction  20  and may press against and close switch  26  (e.g., a dome switch or other suitable switch with open and closed states). In response to closing switch  26 , keyboard control circuitry in keyboard  12  may detect a keypress event and may supply the keypress information to control circuitry in device  10 . The keypress event may then be used as a control input for keyboard  12  and/or device  10 . 
     Springs or other biasing structures such as biasing structures  28  may be used to restore key  14  to its original undepressed state after pressure from finger  16  is released (i.e., biasing structures  28  may push key member  24  upwards in direction  18  when a user lifts finger  16  off of key  14 ). Biasing structures  28  may be formed from springy structures such as foam, elastomeric polymer, spring metal, etc. In the example of  FIG. 4 , biasing structures  28  have been implemented using a scissor-shaped structure with springs that supports and biases key member  24  upwards. Other types of structures for supporting and biasing key members  24  for keys  14  may be used, if desired. 
     As shown in  FIG. 3 , keyboard  12  may have a housing such as housing  32 . Housing  32  may be formed from one or more layers of material such as plastic, metal, fabric, and other materials. Keyboard substrate  30  may be mounted within housing  32 . Biasing structures  28  may be coupled between movable key members such as key member  24  and substrate  30  and/or may be coupled between key member  24  and housing  32  or other structures in keyboard  12 . 
     Keyboard substrate  30  may include signal traces  31  that allow control circuitry to communicate with keys  14  (e.g., traces that allow circuitry to monitor switches  26 ). Substrate  30  may be, for example, a printed circuit (e.g., a flexible printed circuit formed from a sheet of polymer with metal traces or a rigid printed circuit formed form a rigid printed circuit board material such as fiberglass-filled epoxy). Switches  26  may be mounted to substrate  30  (e.g., with solder, conductive adhesive, welds, etc.). Traces  31  on substrate  30  may be coupled between the switch  26  of each key  14  and associated key sensor circuitry so that the circuitry may detect keypress events (i.e., so that the circuitry can determine which keys  14  have been depressed by monitoring which switches  26  have been closed). 
     Key members  24  may be covered with one or more layers of plastic, metal, fabric, or other materials (see, e.g., illustrative layer  22 ). To help ensure that the shape of layer  22  conforms to the raised key shapes of keys  14 , layer  22  may be debossed (embossed) in a die (e.g., a heated die with key-shaped impressions that compresses layer  22  between opposing upper and lower structure into the shapes of keys  14 ). Laser processing techniques and/or other techniques may be used to form perforations and/or other openings in layer  22 , may be used to selectively cut fibers, and/or may otherwise be used to process portions of the material of layer  22  (e.g., to adjust key stiffness, keyboard appearance, and/or other attributes of keyboard  12 ). 
     In addition to pressing on desired keys  14  to supply keypress input, a user of keyboard  12  may desire to supply keyboard  12  with touch input. Keyboard  12  may, if desired, be provided with a trackpad (e.g., a capacitive touch sensor with a rectangular outline or other suitable shape that is used to gather touch input from a user). A trackpad may, as an example, be located below rows of keys in the middle of keyboard  12 . 
     Keyboard  12  may also be provided with a touch sensor that overlaps one or more of keys  14 . This touch sensor may be formed from capacitive touch sensor electrodes or other touch sensor structures. With one illustrative configuration, which may sometimes be described herein as an example, keyboard  12  may incorporate a touch sensor that is formed from conductive strands of material in a layer of fabric (see, e.g., layer  22  of  FIG. 3 ). The conductive strands in a fabric touch sensor may include horizontal strands of material that overlap with perpendicular vertical strands of material to form a grid of touch sensor electrodes that intersect at an array of intersection locations. A fabric touch sensor of this type may, as an example, overlap most or all of keys  14  and thereby may serve as a keyboard-sized integral touch surface with which a user may supply touch input (multitouch gestures, single-finger pointer-control input for an on-screen cursor, swipes, taps, and other touch commands). To conserve space in this type of keyboard, it may be desirable to omit any separate trackpads (i.e., keyboard  12  may be formed from an array of keys and a touch sensor that extends over some or all of the keys and need not have any separate trackpad structures). Configurations of this type may sometimes be described herein as an example. In general, keyboard  12  may include any suitable input-output devices (e.g., buttons, capacitive touch sensors or other touch sensors, etc.). 
     Keyboard  12  may include a key member support structure such as key member support structure  34  of  FIG. 5 . Support structure  34 , which may sometimes be referred to as a key support layer, key support structure, or key web, may have an array of openings. The array of openings may be patterned to accommodate a desired key layout for keyboard  12 . Each opening in support structure  34  may receive a respective movable key member  24  for a respective key  14 . Key support structure  34  may help maintain key members  24  in desired positions within keyboard  12 . Key support structure  34  may be formed from a layer of plastic or other suitable materials. If desired, key support structure  34  may be omitted from keyboard  12  (e.g., in configurations in which key members  24  are secured to substrate  30  using biasing structures and/or other attachment mechanisms, configurations in which key members  24  are maintained in desired positions using layer  22 , etc.). 
       FIG. 6  is a circuit diagram of an illustrative keyboard. As shown in  FIG. 6 , keyboard  12  may include control circuitry  36  such as touch sensor circuitry  40  and key sensor circuitry  38 . Keyboard  12  may have an array of switches  26  ( FIG. 3 ) associated with a corresponding array of keys  14 . 
     Signal paths such as paths  48  (e.g., traces  31  on substrate  30 ) may be used to couple key sensor circuitry  38  to the switches  26  of keys  14 . Whenever a user presses on a given one of keys  14 , the switch  26  in that key will change stage (e.g., from open to closed). Sensor circuitry  38  monitors the status of all of switches  26  in keyboard  12  and, in response to detection of a change of switch state, generates corresponding output signals on path  42  (e.g., signals that inform control circuitry in device  10  or other equipment of each detected key press event). 
     Conductive lines  46  may serve as capacitive electrodes in a capacitive touch sensor (touch sensor grid) that overlaps keys  14 . Any suitable number of horizontal and vertical lines  46  may overlap each key  14 . For example, there may be 1-5, more than 2, more than 3, 2-4, fewer than 10, fewer than 5, or other suitable number of horizontal lines  46  overlapping each key  14  and there may be 1-5, more than 2, more than 3, 2-4, fewer than 10, fewer than 5, or other suitable number of vertical lines  46  overlapping each key  14 . Conductive lines  46  may be formed from patterned thin-film metal traces in layer  22  (e.g., in scenarios in which layer  22  is formed from a layer of plastic), may be formed from conductive strands of material (e.g., in scenarios in which layer  22  is formed from a layer of fabric), and/or may be formed from other conductive structures that form capacitive touch sensor electrodes. Configurations in which lines (electrodes)  46  are formed from conductive strands of material may sometimes be described herein as an example. 
     As shown in  FIG. 6 , touch sensor circuitry  40  may be coupled to a horizontal set of lines  46  and a perpendicular set of vertical lines  46 . Touch sensor circuitry  40  may provide drive signals D to one of these sets of lines  46  (i.e., horizontal lines  46  in the example of  FIG. 6 ) and may gather corresponding sense signals S on the other of these sets of lines  46  (i.e., vertical lines  46  in the example of  FIG. 6 ). Capacitive coupling between the drive and sense lines varies in the presence of a user&#39;s finger over a drive-line-to-sense-line intersection. As a result, touch sensor circuitry  40  can process the drive and sense signals to determine which of the intersections of the horizontal and vertical lines  46  are being overlapped by a user&#39;s finger(s) or other external objects. When touch input is detected in this way, touch sensor circuitry  40  may provide a processor or other control circuitry in device  10  or other equipment with information on the touch input using a path such as path  44 . 
     In a typical scenario, a user may enter text or other key press input into keyboard  12  by typing on keys  14 . Key sensor circuitry  38  may convey information on the text or other input that the user is typing into keyboard  12  over path  42 . When the user desires to reposition an on-screen cursor, to make a multitouch gesture (e.g., a pinch-to-zoom gesture, a two-finger swipe, a three-finger swipe, a two-finger or three-finger tap, etc.), to make a one-finger swipe or other gesture, or to supply keyboard  12  with other touch input, the user may move one or more of the user&#39;s fingers across the surface of keys  14 . During touch input events such as these, touch sensor circuitry  40  may monitor capacitance changes at the intersections of the horizontal and vertical capacitive touch sensor electrodes (paths  46 ) to gather touch input data and may supply the touch input that is gathered from the capacitive touch sensor electrodes to control circuitry such as control circuitry in device  10  and/or control circuitry in keyboard  12  via path  44 . 
     Touch sensor electrodes  46  may be formed from conductive strands of material in layer  22 . Layer  22  may, as an example, include fabric. The fabric may be woven, knitted, or braided and/or may include strands of material that have been intertwined using other techniques (e.g., felt). With one suitable arrangement, which may sometimes be described herein as an example, the fabric of layer  22  may be woven fabric and electrodes  46  may be formed from selected warp and weft strands in the woven fabric. 
       FIG. 7  is a top view of an illustrative woven fabric of the type that may be used in layer  22  of keyboard  12 . As shown in  FIG. 7 , fabric  50  may include warp strands  52  and weft strands  54 . Warp strands  52  run along a first dimension of fabric  50  (e.g., the vertical dimension in the orientation of  FIG. 7 ) and weft strands  54  run perpendicularly along a second dimension of fabric  50  (e.g., the horizontal dimension in the orientation of  FIG. 7 ). Some of warp strand  52  such as strands  521  may be insulating and some of strands  52  may such as strands  52 C may be conductive and may therefore serve as the vertically extending electrodes  46  in the touch sensor of  FIG. 6 . Some of weft strands  54  such as weft strands  541  may be insulating and some of strands  54  may be conductive such as strands  54 C and may therefore serve as horizontally extending electrodes  46  in the touch sensor of  FIG. 6 . Woven fabric  50  of  FIG. 7  has a plain weave, but in general, fabric  50  may have any suitable construction (e.g., fabric  50  may have a basket weave or any other suitable fabric construction). Plain weave fabric constructions may sometimes be described herein as an example. 
     The strands of material in fabric  50  such as strands  52  and  54  may each include one or more monofilaments (sometimes referred to as fibers or monofilament fibers). The monofilaments may have one or more layers (e.g., a core layer alone, a core layer with an outer coating, a core layer with an inner coating layer that is covered with an outer coating layer, a core layer coated with three or more additional layers, etc.). Strands of material that are formed from intertwined monofilaments may sometimes be referred to as yarns, threads, multifilament strands or fibers, etc. In general, any suitable types of strands or combination of different types of strands may be used in forming fabric  50  (e.g., monofilaments, yarns formed from multiple monofilaments, etc.). Strands with multiple monofilaments may have 2-200 monofilaments, 2-50 monofilaments, 2-4 monofilaments, 2 monofilaments, 4 monofilaments, fewer than 10 monofilaments, 2-10 monofilaments, fewer than 6 monofilaments, more than 2 monofilaments, or other suitable number of monofilaments. 
     Insulating strands may be formed from one or more dielectric materials such as polymers, cotton and other natural materials, etc. Conductive strands may be formed from metal or other conductive material and optional dielectric. For example, conductive strands may be formed from solid monofilament wire (e.g., copper wire), wire that is coated with one or more dielectric and/or metal layers (e.g., copper wire that is coated with polymer), a monofilament of polymer coated with metal or other conductive material, a monofilament of polymer coated with metal that is covered with an outer polymer coating, etc. The diameter of the monofilaments may be 5-200 microns, more than 10 microns, 20-30 microns, 30-50 microns, more than 15 microns, less than 200 microns, less than 100 microns, or other suitable diameter. The thickness of each of the coatings in a monofilament may be less than 40% of the diameter of the monofilament, less than 10% of the diameter, less than 4% of the diameter, more than 0.5% of the diameter, 1-5% of the diameter, or other suitable thickness. If desired, conductive monofilaments may be intertwined to form conductive yarn. Conductive yarn may include only conductive monofilaments or may include a combination of conductive monofilaments and insulating monofilaments. 
     Fabric  50  may have a relatively thin single-layer construction of the type shown in  FIG. 8  or may have a three-dimensional construction. If desired, a layer of woven material may be supported by a spacer structure. As shown in  FIG. 9 , woven layer  50 W of fabric  50  may be supported by spacer structures  50 D. Structures  50 D may be formed from a substrate layer (e.g., a layer of plastic, etc.) and associated compressible structures (e.g., foam, elastomeric material, three-dimensional multilayer fabric, etc.) and/or may be formed by three-dimensional weaving or other fabric construction techniques. If desired, a printed circuit or other substrate may be included in structures  50 D. A ground plane or other conductive structures may, if desired, be spaced apart from a grid of electrodes (conductive strands in woven layer  50 D). With an arrangement of this type, touch sensor signals may be gathered using drive and sense lines formed from conductive strands of material in fabric layer  50 W and force measurements may be made by detecting changes in the capacitance between conductive strands in fabric  50 W and ground plane or other conductive structures (e.g., metal traces on a printed circuit) that are spaced apart from layer  50 W. These changes in capacitance may arise, for example, when a user&#39;s finger compresses spacer  50 D and thereby reduces the distance between the conductive strands in layer  50 W and underlying conductive structures. Keys  14  may be formed from rectangular sections of the structure shown in  FIG. 9  (i.e., pads that serve as keys may be formed from compressible fabric structures) in addition to forming keys  14  or instead of forming keys  14  from movable key members  24 . 
     In keyboard  12 , movable key members  24  may bear against dome switches such as dome switch  26  or other suitable switch structures mounted on substrate  30 . The cross-sectional side views of illustrative keyboards  12  in  FIGS. 10 and 11  have key members  24  with central downward protruding portions that bear against respective switches  26 . Biasing structures  28  of  FIG. 3 , scissor mechanisms such as structure  28  of  FIG. 4 , or other suitable structures may be used to bias and support key members  24 . In the example of  FIG. 5 , key member  24  has flanged portions that catch under key support structure  34  and help retain key members  24  within the openings of key support structure  34 . In configurations of the type shown in  FIGS. 10 and 11 , key members  24  do not have any flanged portions and may be retained by overlapping layers of fabric, by the biasing structures  28 , or other suitable retention mechanisms. The key member arrangements of  FIGS. 10 and 11  and the key member arrangements of  FIGS. 3, 4, and 5  are presented as examples. In general, keys  14  may have any suitable key members. 
     As shown in  FIG. 10 , keyboard  12  and key members  24  may be covered with a single layer of material  22  such as a single layer of fabric  50 . Adhesive  56  may be used to attach layer  22  to key members  24  and may be used to attach layer  22  to key support structure  34  in keyboard configurations that include a key support structure such as the keyboard configuration of  FIG. 5 . 
     Conductive strands in fabric  50  of layer  22  may be made visually indistinct from insulating strands in fabric  50  by matching the size and/or color of the insulating and conductive strands. For example, the diameters of the conductive strands and insulating strands may differ by less than 50%, less than 20%, less than 5%, 1-10%, more than 0.1%, or other suitable amount so that the conductive strands are not visibly distinct from the insulating strands. The conductive strands may also be coated with colored polymer having a color that matches the color of the insulating strands of material in fabric  50  or may otherwise be treated so that the appearance of the conductive strands matches that of the insulating strands. As an example, fabric  50  and/or the conducting and/or insulating strands may be coated with a colored polymer treatment (e.g., a colored ink coating such as a gray, black, or white coating, etc.). If desired, conductive strands may be formed from conductive monofilaments that are surrounded by intertwined insulating monofilaments, thereby hiding the conductive material in the conductive strands from view. The insulating monofilaments in conductive strands with this type of arrangement may have the same appearance (e.g., the same color) as insulating monofilaments in insulating strands of material in fabric  50  (as an example). 
     If desired, conductive strands of material and other structures in fabric  50  that are associated with forming the touch sensor may be hidden from view by covering fabric  50  with an additional layer of material. This type of arrangement is shown in  FIG. 11 . Fabric  50  (e.g., woven fabric with sets of horizontal and vertical conductive strands of material that serve as capacitive touch sensor electrodes as described in connection with  FIG. 6 ) may be used in forming inner layer  22 B. Layer  22 B may be attached to button member  24  by adhesive layer  56 - 3 . Outer layer  22 T may cover inner layer  22 B and may therefore hide layer  22 B from view. Outer layer  22 T may be a layer of plastic, a layer of fabric, and/or one or more layers of other materials. Outer layer  22 T may be formed solely from insulating strands or may be formed from strands of other materials that provide keyboard  12  with an attractive external appearance. Adhesive  56 - 1  and  56 - 2  may be used in attaching outer layer  22 T to inner layer  22 B. Adhesive may also be used in attaching fabric in layer  22  of  FIG. 10  and/or in layers  22 B of  FIG. 11  to key support structure  34  ( FIG. 5 ). Gaps may be formed in the adhesive layers along the peripheral edges of key members  24  (see, e.g., gap  58  of  FIG. 11 , which separates adhesive layer  56 - 1  on the upper surface of key member  24  and adhesive layer  56 - 2 , which joins layers  22 T and  22 B in the portions of keyboard  12  that lie between adjacent keys  14 ). These gaps may help enhance the flexibility of the fabric and other layers of material that overlap key members  24  and thereby helps allow key members  24  to move freely when pressed and released by a user. Perforations in layers  22 T and/or  22 B may also be provided around the edges of keys  14  to facilitate key movement. 
     It may be desirable to form the conductive strands of material in fabric  50  that serve as the capacitive touch sensor electrodes for the touch sensor in the outermost layer (or nearly outermost layer) of keyboard  12  as shown in  FIG. 10  to enhance touch sensor functionality (i.e., to make accurate capacitance measurements by omitting unnecessary materials between the touch sensor electrodes and the fingers of a user). In configurations in which fabric  50  is formed as the outermost keyboard layer, conductive strands in fabric  50  may be formed on the underside of fabric  50  as shown in  FIG. 12  (see, e.g., illustrative conductive warp strands  52 C that are hidden under overlapping weft strands  541 ). The construction of fabric  50  in this type of arrangement may allow warp strands  52 C to be mostly located under weft strands  541  and rarely above weft strands  541 . The same arrangement may also be used to hide conductive weft strands under insulating warp strands. If desired, touch sensor electrodes formed from conductive strands can also be hidden from view by applying polymer coatings or other coatings to the strands of fabric  50 , by using conductive strands in fabric  50  in which conductive fibers are surrounded by insulating fibers, and otherwise matching the appearance of the conductive strands to the insulating strands. 
     The foregoing is merely illustrative and various modifications can be made by those skilled in the art without departing from the scope and spirit of the described embodiments. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20170323
Publication Date: 20200804
Grant Date: 20200804
Priority Date: 20160504
Inventors: SUNSHINE, Daniel D.
PODHAJNY, DANIEL A.
KINDLON, DAVID M.
Assignee: APPLE INC
CPC Classifications: [{"code": "H01H2223/052", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2223/046", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2215/008", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2203/01", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2203/0085", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1662", "inventive": true, "first": false, "tree": "[]"}, {"code": "D10B2401/16", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/163", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/03547", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0213", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/169", "inventive": true, "first": false, "tree": "[]"}, {"code": "D03D1/0088", "inventive": true, "first": false, "tree": "[]"}, {"code": "H03K17/962", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/044", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F2203/04111", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/0416", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F2203/04104", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/0213", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/0213", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/0416", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/044", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F2203/04111", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F2203/04104", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 71838781