PATENT DOCUMENT

Publication Number: US-10524040-B2
Application Number: US-201816194130-A
Country: US
Kind Code: B2

Title: Headphones with orientation sensors

Abstract:
An electronic device such as a pair of headphones may be provided with ear cups having speakers for playing audio to a user. Capacitive sensor electrodes may be used in capturing capacitive sensor ear images that are processed by a machine learning classifier to determine whether the headphones are being worn in a reversed or unreversed orientation. The capacitive sensor electrodes may include grill electrodes that overlap at least part of a speaker grill, cushion electrodes that make capacitive sensor measurements through ring-shaped ear cup cushions that surround the speaker grills, and ring electrodes. The ring electrodes may be formed from metal traces on a flexible printed circuit. The flexible printed circuit may include a portion that wraps around each speaker grill and that is surrounded by a corresponding one of the cushions.

Claims:
What is claimed is: 
     
       1. Headphones configured to be worn in an orientation that is unreversed or reversed, comprising:
 first and second ear cups, wherein each of the first and second ear cups includes:
 a speaker; 
 a grill with openings overlapping the speaker; and 
 a cushion surrounding the grill; 
 
 capacitive sensor circuitry including cushion electrodes; and 
 control circuitry configured to gather capacitive sensor ear images at least partly through the cushion of at least one of the first and second ear cups using the cushion electrodes. 
 
     
     
       2. The headphones defined in  claim 1  wherein the control circuitry is configured to determine the orientation based on the capacitive sensor ear images gathered with the cushion electrodes. 
     
     
       3. The headphones defined in  claim 2  further comprising grill electrodes, wherein the control circuitry is configured to gather the capacitive sensor ear images at least partly through the grill of at least one of the first and second ear cups using the grill electrodes. 
     
     
       4. The headphones defined in  claim 3  further comprising a ring of ring electrodes that surrounds the grill and that is surrounded by the cushion electrodes, wherein the control circuitry is configured to gather the capacitive sensor ear images at least partly with the ring electrodes. 
     
     
       5. The headphones defined in  claim 4  wherein the control circuitry is configured to determine the orientation by applying a machine learning classifier to the capacitive sensor ear images. 
     
     
       6. The headphones defined in  claim 4  wherein at least some of the grill electrodes have a polar layout. 
     
     
       7. The headphones defined in  claim 4  wherein the first and second ear cups each have a fabric covering layer. 
     
     
       8. The headphones defined in  claim 7  wherein the first and second ear cups each have a mesh layer with openings and wherein the grill of each of the first and second ear cups is interposed between the mesh layer of that ear cup and the fabric covering layer of that ear cup. 
     
     
       9. The headphones defined in  claim 4  further comprising a flexible printed circuit having metal traces that form at least the ring electrodes and the grill electrodes. 
     
     
       10. The headphones defined in  claim 4  wherein the grill electrodes are arranged in a ring pattern on a printed circuit substrate with a central opening overlapping one of the speakers. 
     
     
       11. Headphones, configured to be worn in an orientation that is unreversed or reversed, comprising:
 first and second ear cups, wherein each of the first and second ear cups includes:
 a speaker; 
 a grill with openings overlapping the speaker; and 
 a ring-shaped cushion; 
 
 capacitive sensor circuitry including a ring of ring electrodes in each of the first and second ear cups that surrounds the grill and that is surrounded by the ring-shaped cushion; and 
 control circuitry configured to gather capacitive sensor ear images at least partly using the ring electrodes. 
 
     
     
       12. The headphones defined in  claim 11  wherein the control circuitry is configured to determine the orientation based on the capacitive sensor ear images gathered with the ring electrodes. 
     
     
       13. The headphones defined in  claim 12  further comprising cushion electrodes in the first and second ear cups, wherein the control circuitry is configured to gather the capacitive sensor ear images at least partly by making capacitive sensor measurements through the cushions with the cushion electrodes. 
     
     
       14. The headphones defined in  claim 13  further comprising grill electrodes overlapped by each of the grills, wherein the control circuitry is configured to gather the capacitive sensor ear images at least partly through the grills using the grill electrodes. 
     
     
       15. The headphones defined in  claim 14  wherein the control circuitry is configured to determine the orientation by applying a machine learning classifier to the capacitive sensor ear images. 
     
     
       16. The headphones defined in  claim 15  further comprising a flexible printed circuit having metal traces that form at least the grill electrodes. 
     
     
       17. The headphones defined in  claim 16  wherein the flexible printed circuit has an opening that overlaps a central portion of the grill. 
     
     
       18. The headphones defined in  claim 17  wherein the metal traces further form at least some of the ring electrodes. 
     
     
       19. A wearable device, comprising:
 a first ear cup having a first speaker overlapped by a first speaker grill and having a first ring-shaped cushion that surrounds the first speaker grill; 
 a second ear cup having a second speaker overlapped by a second speaker grill and having a second ring-shaped cushion that surrounds the second speaker grill; 
 a support structure that couples the first and second ear cups; and 
 capacitive sensor circuitry configured to capture capacitive sensor ear images at least partly by making capacitive sensor measurements through the first and second ring-shaped cushions using cushion electrodes that are overlapped by the first and second ring-shaped cushions. 
 
     
     
       20. The wearable device defined in  claim 19  further comprising:
 first and second flexible printed circuits having metal traces that form ring electrodes, wherein the first flexible printed circuit wraps at least partly around the first speaker grill and is surrounded by the first ring-shaped cushion and wherein the second flexible printed circuit wraps at least partly around the second speaker grill and is surrounded by the second ring-shaped cushion.

Description:
This application claims priority to U.S. provisional patent application No. 62/623,421 filed Jan. 29, 2018, which is hereby incorporated by reference herein in its entirety. 
    
    
     FIELD 
     This relates generally to electronic devices, and, more particularly, to electronic devices such as headphones. 
     BACKGROUND 
     Electronic devices such as headphones may contain audio circuitry and speakers for playing audio content for a user. To ensure satisfactory playback of content through the left and right speakers of a set of headphones, the left and right speakers of many headphones are labeled “left” and “right.” If a user accidentally wears the headphones in the incorrect orientation with the left speaker on right ear and right speaker on left ear, stereo audio playback will be reversed from its expected configuration. This can lead to undesirable user experiences such as when a user is listening to a movie soundtrack and action on the right of the screen results in sounds in the user&#39;s left ear. 
     SUMMARY 
     An electronic device such as a pair of headphones may be provided with ear cups having speakers for playing audio to a user. Control circuitry in the electronic device may be used in determining the orientation of the headphones on the head of a user and in taking suitable action in response to the orientation. The control circuitry may, for example, reverse left and right audio channel assignments in response to determining that the headphones are being worn in a reversed orientation. 
     During operation, capacitive sensor electrodes may be used by the control circuitry in capturing capacitive sensor ear images that are processed by a machine learning classifier. The machine learning classifier may be used to determine whether the headphones are being worn in a reversed or unreversed orientation. 
     The capacitive sensor electrodes may include grill electrodes that overlap at least part of a speaker grill. The grill electrodes may be formed on a flexible printed circuit having an opening that overlaps a central portion of the grill in alignment with a speaker. 
     The capacitive sensor electrodes may also include cushion electrodes that make capacitive sensor measurements through ring-shaped ear cup cushions that surround the speaker grills. 
     Additional ear image data may be captured using ring electrodes. The ring electrodes may be formed from metal traces on a flexible printed circuit such as a flexible printed circuit that also contains grill electrodes or other electrodes. A flexible printed circuit in each ear cup may include a portion that wraps around the speaker grill and that is surrounded by the cushion of that ear cup. 
    
    
     
       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 front view of an illustrative electronic device such as a pair of headphones in accordance with an embodiment. 
         FIG. 3  is a side view of an illustrative ear cup for an electronic device such as a pair of headphones in accordance with an embodiment. 
         FIG. 4  is a cross-sectional side view of an illustrative ear cup for a pair of headphones in accordance with an embodiment. 
         FIG. 5  is a cross-sectional side view of an illustrative flexible printed circuit with metal traces forming capacitive sensor electrodes in accordance with an embodiment. 
         FIG. 6  is a rear perspective view of an interior portion of an ear cup with flexible printed circuit sensor electrodes in accordance with an embodiment. 
         FIG. 7  is a cross-sectional side view of an illustrative covering layer for an electronic device housing in accordance with an embodiment. 
         FIGS. 8 and 9  are front views of illustrative capacitive sensor electrode arrays having respective Cartesian and polar electrodes in accordance with embodiments. 
         FIG. 10  is a flow chart of illustrative operations involved in using an electronic device with capacitive sensor electrodes in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     An electronic device may be provided with sensors that monitor how the device is oriented relative to the body of a user. The sensors may, for example, include capacitive sensors and other sensors that monitor how a user is wearing a pair of headphones on the user&#39;s head (e.g., which ear cup of the headphones is on the user&#39;s left ear and which ear cup of the headphones is on the user&#39;s right ear). Based on knowledge of the orientation of the headphones on the user&#39;s head or other orientation information, the headphones or other electronic device can be configured appropriately. For example, left and right audio channel assignments may be placed in a normal (unreversed) or reversed configuration, and other device settings may be changed. 
     The electronic device may be any electronic equipment that includes a capacitive sensor. For example, the electronic device may be a pair of headphones, ear buds, wearable equipment such as an item in which circuitry has been incorporated into a piece of clothing or other wearable item (e.g., a hat, goggles, helmet, glasses, etc.), a portable device such as a cellular telephone, or other electronic device. Illustrative configurations in which the electronic device is a pair of headphones may sometimes be described herein as an example. 
       FIG. 1  is a schematic diagram of an illustrative electronic device. As shown in  FIG. 1 , electronic device  10  may communicate wirelessly with external equipment such as electronic device  10 ′ using wireless link  28 . Wireless signals for link  28  may be light-based signals, may be acoustic signals, and/or may be radio-frequency signals (e.g., wireless local area network signals, Bluetooth® signals, radio-frequency signals in cellular telephone band, signals at 60 GHz, near field communications signals, etc.). Equipment  10  and equipment  10 ′ may have antennas and wireless transceiver circuitry for supporting wireless communications over link  28  (e.g., input-output circuitry in device  10  such as devices  22  may include antennas, wireless transceiver circuitry, and/or other communications circuitry for supporting wireless communications over link  28 ). Equipment  10 ′ may have the same capabilities as equipment  10  (i.e., devices  10  and  10 ′ may be peer devices) or equipment  10 ′ may include fewer resources or more resources than device  10 . 
     Illustrative device  10  of  FIG. 1  has control circuitry  20 . Control circuitry  20  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  20  may be used to control the operation of device  10  (see, e.g., controller  20 B). The processing circuitry may be based on one or more microprocessors, microcontrollers, digital signal processors, capacitance-to-digital converter chips, baseband processors, power management units, audio chips (e.g., chips with audio amplifiers that can be selectively assigned to play right channel audio in a first ear speaker of device  10  and left channel audio in a second ear speaker or vice versa), application specific integrated circuits, etc. 
     Device  10  may include a sensor for detecting a user&#39;s body parts such as portions of a user&#39;s ears. The sensor may be formed from capacitive sensing circuitry with self-capacitance and/or mutual capacitance electrodes (e.g., capacitive sensor electrodes that form capacitive sensor pixels). This allows the capacitive sensor circuitry to capture capacitive sensor images of a user&#39;s ears. A machine learning classifier may then be used to identify the user&#39;s left and right ears and thereby identify the orientation of electronic device  10  on the head of the user. If desired, the sensor that is used in gathering sensor data from the user&#39;s ears may include optical proximity sensor elements (e.g., light sources such as infrared light-emitting diodes and corresponding infrared light detectors), inductive proximity sensor elements (e.g., induction loops and corresponding current sensing circuits for detecting changes in current due to the changing presence of metals or other materials in the vicinity of the loops), force-based sensors, acoustic sensors, or other sensor circuits that can be configured to gather sensor data (e.g., sensor image data) on the user&#39;s ears. Illustrative configurations in which electronic device  10  has capacitive sensor circuitry for gathering capacitive sensor image data on the user&#39;s ears (capacitive sensor ear images) may sometimes be described herein as an example. 
     As shown in the illustrative configuration of  FIG. 1 , device  10  may include a capacitive sensor having electrodes  40 . Control circuitry  20  may include circuitry for using electrodes  40  in making capacitive sensor measurements. For example, control circuitry may include capacitive sensor circuitry that is coupled to electrodes  40  such as capacitive sensing circuitry  20 A- 2  and switching circuitry such as switch  20 A- 1 . Capacitive sensor electrodes  40  may include reference electrodes  42  and sense electrodes  44  and/or other electrode structures. If desired, a driven shield configuration may be used for electrodes  40 . Switch  20 A- 1  may be dynamically configured based on control signals from controller  20 B so that capacitive sensor measurements can be gathered from a desired pair of electrodes (e.g., a selected electrode  44  and corresponding electrode  42 ) and/or from sets of multiple combined electrodes (e.g., two or more electrodes  44  and two or more respective electrodes  42  that have been combined to enhance detection range). 
     Electrodes  40  may be arranged on one or more substrates to form a two-dimensional capacitive electrode pixel array. This allows capacitive sensor image data to be gathered. The resolution of the capacitive images captured in this way depends on the density of electrodes  40  that are used. For high spatial resolution, numerous electrodes  40  may be include in the capacitive sensor. For ease of processing at lower spatial resolutions, fewer electrodes  40  may be used. In general, any suitable number of electrodes  40  may be included in device  10  (e.g., 10-1000, at least 50, at least 100, at least 200, at least 400, fewer than 300, fewer than 250, etc.). Capacitive sensor electrodes  40  may be formed on one or more substrates such as one or more flexible printed circuits and may be mounted at one or more locations within device  10  (e.g., to gather capacitive sensor images of a user&#39;s ear and surrounding body from multiple different locations). 
     Input-output circuitry in device  10  such as input-output devices  22  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  22  may include buttons, joysticks, scrolling wheels, touch pads, key pads, keyboards, tone generators, vibrators, cameras, sensors  26  (e.g., ambient light sensors, magnetic sensors, force sensors, touch sensors, accelerometers, and other sensors), light-emitting diodes and other status indicators, data ports, displays, etc. Input-output devices  22  may include audio components such as microphones and speakers  24 . Speakers  24  may be mounted in left and right ear cups in over-the-ear or on-the-ear headphones. The headphones may have a supporting member that couples the ear cups together and/or may be coupled using supporting members in a head mounted display (e.g., band or other support structures in a helmet, goggles, or glasses with ear cups), and/or may have other headphone configurations. 
     A user can control the operation of device  10  by supplying commands through input-output devices  22  and may receive status information and other output from device  10  using the output resources of input-output devices  22 . 
     Control circuitry  20  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  20  may use the capacitive proximity sensor formed from electrodes  40  (e.g., a capacitive proximity sensor(s) in one or both ear cups) to gather information on how device  10  is oriented (e.g., which ear cup is located on the user&#39;s right ear and which ear cup is located on the user&#39;s left ear) and other information about the usage of device  10 . This software may also gather and use other information such as accelerometer signals from sensors  26  (e.g., signals indicating that device  10  is in use by a user or is not in use) and may gather and use other information from input-output devices  22  in device  10  (e.g., button input, voice input, and/or other input from a user). A user may, for example, supply input to buttons, touch sensors, accelerometers that detect finger taps, or other devices  22  using one or more fingers and/or other external objects (e.g., a stylus, etc.). 
     The left ear cup, right ear cup, or both the left and right ear cups may be provided with electrodes  40 . The capacitive sensor formed from electrodes  40  may capture capacitive sensor image data from electrodes  40  on one or both ear cups. With this information, device  10  can determine whether the headphones are being worn in an unreversed or in a reversed configuration and can make audio adjustments accordingly (e.g., by adjusting left/right channel assignments using control circuitry  20  such as controller  20 B). 
     Electronic device  10  (and external equipment  10 ′) may, in general, be any suitable electronic equipment. Electronic device  10  (and device  10 ′) may, for example, be a computing 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 (e.g., a watch with a wrist strap), a pendant device, a headphone or earpiece device, a device embedded in eyeglasses or other equipment worn on a user&#39;s head (e.g., a pair of headphones, ear buds, wearable equipment such as an item in which circuitry has been incorporated into a piece of clothing or other wearable item such as a hat, goggles, helmet, glasses, etc.), a portable device such as a cellular telephone, 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 equipment with a display is mounted in a kiosk or automobile, furniture, fabric-based items such as pillows and clothing, equipment that implements the functionality of two or more of these devices, or other electronic equipment. 
       FIG. 2  is a front view of an illustrative electronic device. In the illustrative configuration of  FIG. 2 , device  10  is a portable device such as a pair of headphones (earphones). Other configurations may be used for device  10  if desired. The example of  FIG. 2  is merely illustrative. 
     As shown in  FIG. 2 , device  10  may have ear cups such as ear cups  30 . There may be two ear cups  30  in device  10  that are coupled by a supporting member such as band  34  or other support structure (straps, helmet or goggle structures, parts of glasses, etc.). Band  34  may be flexible and may have a curved shape to accommodate a user&#39;s head. There may be left and right ear cups  30  in device  10 , one for one of the user&#39;s ears and the other for the other of the user&#39;s ears. Each ear cup may have an area such as area  32  (sometimes referred to as a grill area) through which sound may be emitted from a speaker (e.g., a speaker system with one or more drivers). One or more locations in the ear cups may be provided with electrodes  40  so that capacitive proximity sensor measurements may be made of the user&#39;s ear to determine device orientation. Control circuitry  20  may be coupled to electrodes  40  in one or both of the ear cups and may be used in detecting ear patterns of a user&#39;s left and/or right ears. 
     When worn in an unreversed configuration, the right ear cup of device  10  will supply audio to the right ear of the user and the left ear cup of device  10  will supply audio to the left ear of the user. In a reversed configuration, the right ear cup is adjacent to the user&#39;s left ear and the left ear cup is adjacent to the user&#39;s right ear. For correct audio playback, the assignment of the left and right channels of audio that are being played back to the user can be reversed by control circuitry  20  (so that the left channel of audio is played through the right ear cup and vice versa) whenever device  10  is being worn in the reversed configuration. Unreversed right-left channel assignments may be used when device  10  is being worn in the unreversed configuration. 
     Device  10  may have an asymmetrical design or may have a symmetrical design. A symmetrical design may be used to provide device  10  with a desired symmetrical appearance. In some configurations for device  10  (e.g., when device  10  has a symmetrical design), there may be few or no recognizable differences between unreversed and reversed orientations for device  10 . In this type of scenario, it may be desirable to use capacitive proximity sensor input or input from other sensors  26  to determine whether to operate device  10  in an unreversed audio playback or reversed audio playback configuration. Capacitive sensor electrodes  40  on inwardly facing (ear-facing) portions of ear cups  30  may be used to measure the shapes of the user&#39;s ears and thereby determine the orientation of device  10  on the user&#39;s head. 
       FIG. 3  shows the inwardly facing side of an illustrative ear cup. As shown in  FIG. 3 , ear cup  30  may have a ring-shaped cushion  70  that is configured to rest against a user&#39;s head while surrounding a user&#39;s ear. In area  32 , sound may be emitted towards a user&#39;s ear through openings  64  in speaker grill  62 . Speaker grill  62  and other portions of the housing of device  10  (e.g., cushions  70 , band  34 , etc.) may be formed from polymer (plastic), metal, glass, ceramic, fiber-composite materials, wood, fabric, cotton or other natural materials, other materials, and/or combinations of two or more of these materials. Conductive structures (e.g., sheet metal) have the potential to block capacitive sensor operation, so dielectric materials such as polymer, polymer-containing fabrics, and/or other dielectric may be used in locations that overlap sensor electrodes  40 . 
     A cross-sectional side view of an illustrative ear cup when pressed against a user&#39;s head while device  10  is being worn on the user&#39;s head is shown in  FIG. 4 . As shown in  FIG. 4 , device  10  includes ear cup  30 . Ear cup  30  may have housing structures such as outer housing  46 . Ear cup cushion  70  may have a ring shape and may be formed from soft materials (e.g., an outer fabric or polymer layer such a layer  48  surrounding a foam ring or other compressible ring-shaped inner cushion member such as member  50 ). Speaker  58  may be mounted within a cavity in the interior of ear cup  30  between outwardly facing housing structures such as outer housing  46  and speaker grill  62 . In this position, speaker  58  may provide sound through speaker grill openings  64  that is received by ear canal  56  of the user&#39;s ear  54 . If desired, other circuit components  58  (see, e.g., circuitry  20 , input-output devices  22 , etc. of  FIG. 1 ) may be mounted within the interior of ear cup  30 . Circuitry for device  10  may also be mounted within band  34 . 
     Electrodes  40  for the capacitive sensor of device  10  may be mounted in ear cup locations that are adjacent to ear  54  when cushion  70  of ear cup  30  is resting against the side of the user&#39;s head (head  52 ). In this position, electrodes  40  can gather capacitance sensor ear image data (pixel patterns) that allow control circuitry  20  to identify the user&#39;s left and right ears and thereby determine the orientation of device  10  on the user&#39;s head  52 . As shown in the illustrative configuration of  FIG. 4 , electrodes  40  can be mounted in multiple different locations such as (1) the outwardly facing interior surface of cushion  70  (see, e.g., electrodes  40 A), the outwardly facing interior surface of speaker grill  62  (see, e.g., electrodes  40 C), and a circumferential ring-shaped surface of the housing of ear cup  30  that extends between the interior surface of grill  62  and the interior surface of cushion  70  (see, e.g., electrodes  40 B). 
     Electrodes  40 A may gather capacitance measurements through cushion  70  and may therefore sometimes be referred to as cushion electrodes. Cushion electrodes  40 A may be used in detecting when ear cup  30  is resting against head  52  (e.g., when device  10  is being worn by the user). 
     Electrodes  40 C may gather capacitance measurements through speaker grill  62  and may therefore sometimes be referred to as speaker grill electrodes. Electrodes  40 C are directed towards ear  54  and may therefore be used in capturing an image of ear  54  (e.g., to determine the shape and location of ear parts such as the helix, the leg of the helix, the ear hole (for ear canal  56 ), the tragus, the conch, the anti-tragus, and the lobe). Electrodes  40 A and  40 C may lie in parallel planes. The central portion of electrodes  40 C (e.g., a portion overlapping the center of grill  62 ) may be omitted and the substrate on which these electrodes are formed may have an opening aligned with speaker  58 . 
     Electrodes  40 B may be angled (e.g., at 10-80° or other non-zero angle) with respect to the surface normal of the planes in which electrodes  40 A and  40 C lie. Electrodes  40 B form a ring-shaped strip (ring) around the periphery of ear  54  and may therefore sometimes be referred to as ring electrodes. Ring electrodes  40 B are directed towards peripheral portions of ear  54  and may therefore be used in determining the shape of ear  54  and identifying ear shape. Ring electrodes  40 B may surround grill electrodes  40 C and may be surrounded by cushion electrodes  40 A. 
     If desired, electrodes  40  may include additional sets of electrodes in each ear cup or fewer sets of electrodes in each ear cup. The example of  FIG. 4  is merely illustrative.  FIG. 5  is a cross-sectional side view of an illustrative flexible circuit with illustrative electrodes  40 . As shown in  FIG. 5 , electrodes  40  may be mounted on a flexible printed circuit substrate such as substrate  60  (e.g. a flexible layer of polyimide or a sheet of other polymer) and may include one or more layers, internal and/or external traces such as illustrative interconnects  62 , capacitive sensor electrodes on an upper surface of substrate  60  such as electrodes  42  and overlapping capacitive sensor electrodes on an opposing lower surface of substrate  60  such as electrodes  44 , 
       FIG. 6  is a rear view of an interior portion of an illustrative ear cup  30  showing how sensor circuitry for device  10  may be formed from one or more flexible printed circuits (see, e.g., the flexible printed circuit of  FIG. 5 ). A first flexible printed circuit may have a substrate with metal traces patterned to form cushion electrodes  40 A. The first flexible printed circuit may have a planar ring shape with metal traces that form electrodes  44  overlapping corresponding electrodes  42  as shown in  FIG. 5 . A second flexible printed circuit may form ring electrodes  40 B and speaker grill electrodes  40 C. The portion of the second flexible printed circuit that forms ring electrodes  40 B may have metal traces forming electrodes  44  that overlap corresponding electrodes  42 . This portion of the second flexible printed circuit may have a ring shape formed from flexible printed circuit substrate material that is angled at a non-zero angle with respect to electrodes  40 A and  40 C (as an example). Another portion of the second flexible printed circuit or a different flexible printed circuit substrate may form speaker grill electrodes  40 C. This portion of the second flexible printed circuit may have a planar shape and may contain an array of metal electrodes  44  (and overlapped electrodes  42 ) with openings  66  that mate with corresponding speaker grill openings  64  ( FIG. 4 ) to allow sound from speaker  58  to pass through the speaker grill. A central portion of the second flexible printed (e.g., central portion  64 B of  FIG. 6 ) may contain electrodes  40  or may have an opening to enhance sound propagation. 
       FIG. 7  is a cross sectional side view of an illustrative fabric layer and other structures that may be used in forming ear cup  30 . In the example of  FIG. 7 , layers  80  include portions of speaker grill  62 . If desired, fabric and other layers of material may be used in covering housing  46 , cushions  70 , and/or other structures in device  10  (e.g., other structures with electrodes, speaker grill  62 , etc.). 
     As shown in  FIG. 7 , layers  80  may include fabric layer  82 . Fabric layer  82  may serve as a covering layer and may have intertwined strands of material  92 . Strands  92  may be woven, knit, braided, or otherwise intertwined to form fabric  82 . Fabric  82  may be sufficiently porous to allow sound to pass through fabric  82  and/or openings may be formed in fabric  82  in alignment with speaker grill openings and other sound openings. 
     Speaker grill  62  may have openings  64 . Pressure sensitive adhesive layer  84  may be used to attach speaker grill  62  to acoustic mesh layer  86 . Layer  84  may have openings  94 . Openings  94  may have any suitable shape. As an example, one or more of openings  94  may overlap one or more corresponding openings  64  in speaker grill  62 . Acoustic mesh  86  may be formed from intertwined strands of material  88  such as woven strands, etc. Mesh  86  may have smaller openings (pores) than grill  62  and may therefore help prevent dust and other contaminants from entering into the interior of device  10 . Pressure sensitive adhesive  90  may be used to help mount internal structures  100  against mesh  86 . Internal structures  100  may include electrodes  40 , speaker  58 , and/or other internal components. 
     Illustrative electrode patterns for electrodes  40  are shown in  FIGS. 8 and 9 . In the examples of  FIGS. 8 and 9 , electrodes  40  include a central set of electrodes (e.g., for forming speaker grill electrodes  40 C) and an outer set of surrounding electrodes (e.g., for forming ring electrodes  40 B and/or cushion electrodes  40 A. If desired, some of the centermost electrodes  40  may be omitted to accommodate an opening such as opening  64 B of  FIG. 6  (e.g., to form a passageway for sound from speaker  58 ). Electrodes  40  may have outer electrodes with edges that are aligned with lines emanating radially from a central point (sometimes referred to as radially patterned electrodes, radial-edge electrodes, or polar electrodes). The central electrodes of electrodes  40  may have rectilinearly patterned electrodes having edges aligned with Cartesian axes (perpendicular vertical and horizontal axes) as shown in  FIG. 8  or may have additional radially patterned electrodes as shown in  FIG. 9  (e.g., the grill, ring, and/or cushion electrodes may have a polar layout). Other patterns may be used for electrodes  40  if desired. 
       FIG. 10  is a flow chart of illustrative operations involved in using sensor circuitry in device  10  to identify the orientation of device  10  on the head of a user. 
     During the operations of block  101 , a machine learning classifier may be developed. The machine learning classifier may be trained by placing device  10  (or a representative version of device  10 ) on the ears of one or more users (or the ears of phantom users). Modeling operations may also be performed. Using modeling results and/or user studies involving measurements on representative ears, the machining learning classifier can be trained. The machine learning classifier can then be stored in device  10  for subsequent use in the field. 
     During the operations of block  101 , while device  10  is being used by a user, device  10  (e.g., control circuitry  20  such as microprocessor circuitry, circuitry in a capacitance to digital converter, etc.), can use capacitive sensing circuitry (e.g., electrodes  40 ) to gather capacitive sensor data (e.g., capacitive sensor images from the capacitive sensor pixels formed from electrodes  40 ) to monitor for the presence of an on-head state for device  10 . Capacitive sensor measurements may be made with a capacitive sensor that includes electrodes  40 . Capacitive sensors for device  10  may be sensitive to contact by external objects and may detect external objects in the vicinity of the capacitive sensors. Accordingly, capacitive sensors for device  10  may sometimes be referred to as touch sensors and/or proximity sensors. 
     In general, any suitable sensor information may be used in determining when device  10  is present on the head of the user (e.g., accelerometer data indicating device movement, capacitive sensor data, information from a force sensor such as a strain gauge that detects when band  34  has been stretched, output from a pressure activated switch that detects the presence of a user&#39;s ear against device  10 , etc.). With one illustrative approach, capacitive sensor data may be evaluated to determine when device  10  is present on the user&#39;s head. 
     During operation, capacitive sensor readings may be compared to baseline capacitive sensor data (e.g., data taken at a relatively low frame rate of about 1-10 Hz that has been filtered using low-pass filtering to produce a historical average). The comparison of current capacitive sensor data to baseline capacitive sensor data may help avoid false detection events due to temperature drift and other noise sources. In some arrangements, accelerometer data and/or capacitive sensor data may be compared to thresholds to determine whether device  10  is on a user&#39;s head. For example, control circuitry in device  10  can conclude that device  10  is on a user&#39;s head during the operations of block  102  if capacitive sensor readings deviate from baseline capacitive sensor data by more than a threshold amount and/or if accelerometer data has a value that exceeds a predetermined accelerometer threshold value. 
     In response to determining during the on-head state monitoring operations of block  102  that device  10  is on the head of a user, device  10  can gather and process additional data to determine the orientation of device  10  on the user&#39;s head. 
     During the operations of block  104 , capacitive sensor data may be acquired. For example, 10-20 capacitive sensor image frames may be captured and noisy frames discarded. The machine learning classifier developed during the operations of block  101  may then be applied to the capacitive sensor data (capacitive sensor images). The output of the machine learning classifier may include numerical values (e.g., correlation coefficient values between −1 for 0% correlation and +1 for 100% correlation) representing the likelihood of left and right ears being present on the respective ear cups. As an example, if device  10  is oriented so that a first ear cup is present on the user&#39;s left ear and a second opposing ear cup is present on the user&#39;s right ear, the machine learning classifier may generate values of left ear correlation coefficient L=0.9 and right ear correlation coefficient R=−0.85 for the first ear cup and correlation coefficient values of L=−0.92 and R=0.91 for the second ear cup. These values may then be compared to a threshold value (e.g., 0, 0.1, or other suitable correlation coefficient threshold) and a determination of the likely orientation of device  10  on the ears of the user can be made accordingly. 
     Orientation counters can be updated based on the results of the threshold comparisons of block  108 . For example, control circuitry  20  can, during the operations of block  110 , maintain a first orientation counter (e.g., an unreversed orientation counter) and a second orientation counter (e.g., a reversed orientation counter) and can increment these counters based on the comparisons of block  108 . The first counter may be incremented whenever the detected orientation is such that the first cup is on the left ear and the second counter may be incremented in response to determining that the orientation is such that the first cup is on the right ear. In scenarios in which the orientation of device  10  is not clear, neither counter may be incremented. As indicated by line  112 , the operations of blocks  104 ,  106 ,  108 , and  110  can be repeated (e.g., multiple capacitive sensor images can be collected). After sampling is complete, the orientation of device  10  on the user&#39;s head may be determined from the counter with the greatest count (e.g., the orientation of device  10  may be assigned an unreversed or reversed state). If no orientation is clearly determined from the capacitive sensor measurements, control circuitry  20  can play audio instructions for the user (e.g., “tap your right ear cup to continue”) and can monitor accelerometers or other sensors in the ear cups for corresponding vibrations from a user&#39;s finger tap. The finger tap input can be used to identify which ear cup is on the user&#39;s right ear and therefore can be used in identifying the orientation of device  10 . 
     During the operations of block  114 , suitable action may be taken by control circuitry  20  based on the determined orientation of device  10  on the user&#39;s head. For example, audio channel assignments can be made (e.g., to play left channel audio through the speaker in the ear cup on the user&#39;s left ear and to play right channel audio through the speaker in the ear cup on the user&#39;s right ear). 
     During the classification process of  FIG. 10 , capacitive sensor ear images can be compared to baseline images so that a differential image can be analyzed using the machine learning classifier. The classifier may be a linear support vector machine with optional non-linear functions for each input pixel value or combination of pixel values (e.g., non-linear kernels), a quadratic classifier, single or multi-layer perception or neural network classifiers, or other suitable machine learning classifiers. As described in connection with the operations of block  101 , the classifier may be trained using a set of training samples (e.g., based on user studies). The classifier algorithm may be implemented using control circuitry  20  (e.g., microprocessor circuitry, microcontroller circuitry, a capacitance-to-digital converter integrated circuit or other capacitance-to-digital converter circuitry, a digital signal processor, system-on-chip circuitry, etc.). Capacitance sensor electrodes that are used in capturing ear image data may also be used for detecting the presence of ears (e.g., to detect the on-head state) and/or other sensors can be used to detect the on-head state. 
     
       
         
           
               
             
               
                   
               
               
                 Table of Reference Numerals 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                 10 
                 electronic device 
                  10′ 
                 equipment 
               
               
                 20 
                 control circuitry 
                   20A-1 
                 switch 
               
               
                   20A-2 
                 capacitive sensing 
                   20B 
                 controller 
               
               
                   
                 circuitry 
               
               
                 22 
                 input-output devices 
                 24 
                 speaker 
               
               
                 26 
                 sensor 
                 28 
                 link 
               
               
                 30 
                 ear cups 
                 32 
                 area 
               
               
                 34 
                 band 
                 40 
                 electrodes 
               
               
                   40A 
                 electrodes 
                   40B 
                 electrodes 
               
               
                   40C 
                 electrodes 
                 42 
                 electrodes 
               
               
                 44 
                 electrodes 
                 46 
                 housing 
               
               
                 50 
                 member 
                 52 
                 head 
               
               
                 54 
                 ear 
                 56 
                 ear canal 
               
               
                 58 
                 speaker 
                 60 
                 substrate 
               
               
                 62 
                 grill 
                 64 
                 openings 
               
               
                   64B 
                 openings 
                 66 
                 openings 
               
               
                 70 
                 cushions 
                 80 
                 layers 
               
               
                 82 
                 fabric 
                 84 
                 layer 
               
               
                 86 
                 mesh 
                 88 
                 material 
               
               
                 90 
                 adhesive 
                 92 
                 strands 
               
               
                 94 
                 openings 
                 100  
                 internal structures 
               
               
                   
               
            
           
         
       
     
     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: 20181116
Publication Date: 20191231
Grant Date: 20191231
Priority Date: 20180129
Inventors: HAJATI, ARMAN
DATTA, SUPRATIK
Assignee: APPLE INC
CPC Classifications: [{"code": "H04R1/1041", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R2201/023", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R5/033", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/1008", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/1008", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/1041", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R5/04", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/1058", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/1041", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R1/1008", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/1058", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R5/033", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R2201/023", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R5/04", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 67392578