PATENT DOCUMENT

Publication Number: US-10291976-B2
Application Number: US-201715808733-A
Country: US
Kind Code: B2

Title: Electronic devices with configurable capacitive proximity 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 proximity sensor electrodes having acoustic openings may overlap the speakers. The capacitive proximity sensor electrodes may include electrodes that are arranged in a ring. Control circuitry in the electronic device may use the capacitive proximity sensor electrodes to measure ear patterns of a user when the headphones are being worn on the head of the user. The control circuitry may include switching circuitry that allows the electrodes to be dynamically combined to form electrodes of enlarged area to enhance detection range or to form separate electrodes to enhance spatial resolution.

Claims:
What is claimed is: 
     
       1. A wearable electronic device, comprising:
 a controller; and 
 a capacitive proximity sensor coupled to the controller, wherein the capacitive proximity sensor includes:
 electrodes; 
 switching circuitry coupled to the electrodes; and 
 a capacitive sensing circuit coupled to the electrodes and the switching circuitry, wherein the controller is configured to adjust the switching circuitry to dynamically combine at least one set of the electrodes to form at least one corresponding unitary electrode of enhanced size. 
 
 
     
     
       2. The wearable electronic device defined in  claim 1  further comprising a speaker, wherein at least some of the electrodes are arranged in an array overlapping the speaker. 
     
     
       3. The wearable electronic device defined in  claim 2  wherein at least some of the electrodes have acoustic openings configured to pass sound from the speaker. 
     
     
       4. The wearable electronic device defined in  claim 3  wherein the capacitive proximity sensor includes a substrate having openings aligned with the acoustic openings of the electrodes. 
     
     
       5. The wearable electronic device defined in  claim 4  wherein the electrodes include reference electrodes on a first side of the substrate and sense electrodes on an opposing second side of the substrate. 
     
     
       6. The wearable electronic device defined in  claim 5  wherein the second side of the substrate faces the speaker and wherein the wearable electronic device further comprises at least one layer of fabric configured to allow the sound from the speakers to pass. 
     
     
       7. The wearable electronic device defined in  claim 6  further comprising a mesh layer interposed between the layer of fabric and the substrate. 
     
     
       8. The wearable electronic device defined in  claim 5  wherein at least some of the sense electrodes are arranged in a ring. 
     
     
       9. The wearable electronic device defined in  claim 1  wherein the controller is configured to recognize left ear sensor measurement patterns and right ear sensor measurement patterns in sensor measurements gathered with the capacitive proximity sensor. 
     
     
       10. The wearable electronic device defined in  claim 1  further comprising an accelerometer, wherein the controller is configured to gather capacitive proximity sensor measurements with the capacitive proximity sensor at least partly in response to information from the accelerometer. 
     
     
       11. The wearable electronic device defined in  claim 1  further comprising first and second ear cups having first and second respective speakers, wherein at least some of the electrodes are in the first ear cup. 
     
     
       12. The wearable electronic device defined in  claim 1  further comprising at least one layer of fabric overlapping the electrodes. 
     
     
       13. The wearable electronic device defined in  claim 12  wherein the electrodes are formed on a substrate having substrate openings and have electrode openings that overlap the substrate openings, the wearable electronic device further comprising a speaker configured to emit sound that passes through the substrate openings, electrode openings, and the layer of fabric. 
     
     
       14. Headphones, comprising:
 first and second ear cups; 
 a structure that couples the first and second ear cups; 
 control circuitry; and 
 capacitive proximity sensor electrodes in the first and second ear cups, wherein the control circuitry is configured to dynamically combine at least a selected number of the capacitive proximity sensor electrodes to form at least one corresponding unitary electrode. 
 
     
     
       15. The headphones defined in  claim 14  further comprising:
 a first speaker in the first ear cup that is overlapped by a first set of the capacitive proximity sensor electrodes; and 
 a second speaker in the second ear cup that is overlapped by a second set of the capacitive proximity sensor electrodes, wherein at least some of the capacitive proximity sensor electrodes in the first and second sets of capacitive proximity sensor electrodes have acoustic openings. 
 
     
     
       16. The headphones defined in  claim 15  further comprising an accelerometer, wherein the control circuitry is configured to use the capacitive proximity sensor electrodes to make ear pattern measurements in response to detection of motion with the accelerometer. 
     
     
       17. The headphones defined in  claim 16  wherein the control circuitry is configured to adjust left and right audio channel assignments for the first and second speakers based on information from the capacitive proximity sensor electrodes. 
     
     
       18. Headphones, comprising:
 first and second speakers; 
 control circuitry; and 
 capacitive proximity sensor electrodes overlapping at least one of the first and second speakers, wherein the control circuitry is configured to operate in:
 a first mode in which at least some of the capacitive proximity sensor electrodes are combined by the control circuitry to enlarge sensor electrode area and enhance detection range; and 
 a second mode in which fewer of the capacitive proximity sensor electrodes are combined than in the first mode to enhance detection spatial resolution. 
 
 
     
     
       19. The headphones defined in  claim 18  wherein the control circuitry is further configured to operate in a third mode in which fewer of the capacitive proximity sensor electrodes are combined than in the second mode. 
     
     
       20. The headphones defined in  claim 19  further comprising an accelerometer, wherein the control circuitry is configured to make ear pattern measurements with the capacitive proximity sensor electrodes in the first mode in response to detection of motion with the accelerometer. 
     
     
       21. Apparatus, comprising:
 a controller; 
 fabric; and 
 a capacitive proximity sensor coupled to the controller and overlapped by the fabric, wherein the capacitive proximity sensor includes:
 electrodes; 
 switching circuitry coupled to the electrodes; and 
 a capacitive sensing circuit coupled to the electrodes and the switching circuitry, wherein the controller is configured to adjust the switching circuitry to dynamically combine at least one set of the electrodes to form at least one corresponding unitary electrode of enhanced size.

Description:
This application claims the benefit of provisional patent application No. 62/480,218, filed Mar. 31, 2017, which is hereby incorporated by reference herein in its entirety. 
    
    
     BACKGROUND 
     This relates generally to electronic devices, and, more particularly, to electronic devices such as headphones. 
     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. 
     It would therefore be desirable to be able to provide improved electronic devices such as improved headphones. 
     SUMMARY 
     An electronic device such as a pair of headphones may be provided with ear cups having speakers for playing audio to a user. An array of sensor structures such as capacitive proximity sensor electrodes may overlap the speakers. The capacitive proximity sensor electrodes may include electrodes that are arranged in a ring. Acoustic openings may be formed in the electrodes to accommodate sound from the speakers. In some configurations, the electrodes may include sense electrodes on a first side of substrate and corresponding reference electrodes on a second side of the substrate. The substrate may have acoustic openings that overlap the acoustic openings in the electrodes. One or more layers such as fabric layers and/or mesh layers may overlap the electrodes. 
     Control circuitry in the electronic device may use the capacitive proximity sensor electrodes to measure user ear patterns when the headphones are being worn on the head of a user. By detecting left ear patterns and right ear patterns in the sensor measurements, the control circuitry can recognize whether the headphones are being worn in a normal or reversed orientation and can adjust the left and right channel assignments for the audio being played back by the speakers accordingly 
     The control circuitry may include switching circuitry that allows the electrodes to be dynamically combined to form electrodes of enlarged area to enhance detection range. In some operating modes, progressively fewer electrodes may be combined to enhance spatial resolution. 
     This technique of selectively enhancing capacitive array sensitivity may be used in any suitable device with a capacitive sensor array (e.g., a pillow with capacitive sensors that has an ear sensor to determine which side a person is sleeping on, etc.). Moreover, other types of sensor (e.g., optical proximity sensors, inductive proximity sensors, etc.) may also have arrays of sensor elements that are dynamically combined to trade off sensitivity (detection range) increases for spatial resolution and vice versa. The use of arrays of capacitive proximity sensor electrodes is merely illustrative. 
    
    
     
       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 perspective view of an illustrative electronic device such as a pair of headphones in accordance with an embodiment. 
         FIG. 3  is a diagram of an illustrative electrode layout for an electronic device such as a pair of headphones in accordance with an embodiment. 
         FIG. 4  is a diagram of an illustrative ear of a user in accordance with an embodiment. 
         FIG. 5  is a graph showing how capacitive proximity sensor output may vary as a function of distance from an object being measured and as a function of electrode size in accordance with an embodiment. 
         FIG. 6  is a cross-sectional side view of a portion of an ear cup in a pair of headphones showing how electrodes in the headphones may be separated from different portions of a user&#39;s ear by different ear-to-electrode spacing distances in accordance with an embodiment. 
         FIG. 7  is a cross-sectional side view of a portion of an illustrative capacitive proximity sensor showing how electrodes for the sensor may be supported by a substrate in accordance with an embodiment. 
         FIG. 8  is a top view of an illustrative capacitive sensor electrode with acoustic openings in accordance with an embodiment. 
         FIG. 9  is a cross-sectional side view of an illustrative ear cup in a pair of headphones in accordance with an embodiment. 
         FIG. 10  is a flow chart of illustrative operations involved in using an electronic device with dynamically configurable capacitive proximity 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 proximity 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 stereo headphone channel assignments may be placed in a normal or reversed configuration, and other device settings may be changed. The electronic device may be any electronic equipment that includes a capacitive sensor array. For example, the electronic device may be formed from fabric (e.g., the device may be a pillow such as a pillow that uses an array of capacitive proximity sensors that are configured to measure a user&#39;s ears to determine which side a user is sleeping on), may be a wearable device (e.g., the device may be a piece of clothing that includes sensors and processing circuitry), may be incorporated into an embedded system (e.g., in furniture, an automobile, or other environment), may be incorporated into a cellular telephone with an array of capacitive sensors on a display or housing structure, or may be other suitable electronic equipment with an array of dynamically configurable sensors. 
       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, 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 that has sensor elements that can be dynamically reconfigured to enhance detection range or to enhance spatial resolution (see, e.g., sensors  26  of  FIG. 1 ). The dynamically reconfigurable elements may be, for example, 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), or other proximity sensor circuits that can be configured to join some or all of the elements together to enhance detection sensitivity or configured to separate these elements to enhance spatial resolution. Controller  20 B may control switching circuitry (e.g., switching circuitry  20 A- 1  or other suitable switching circuitry in device  10  coupled to sensor elements  26 ) to dynamically combine sets of two or more proximity sensor elements to strengthen the signals from those sensors and thereby enhance range or may configure the switching circuitry so that controller  20 B receives individual sensor element measurements, thereby enhancing sensor measurement spatial resolution. Configurations in which elements  40  are capacitive proximity sensor electrodes may sometimes be described herein as an example. This is, however, merely illustrative. Device  10  may be any suitable type of equipment and may include any suitable array of dynamically reconfigurable sensor elements (e.g., any suitable array of dynamically reconfigurable proximity sensor elements). 
     As shown in the illustrative configuration of  FIG. 1 , device  10  may include a capacitive proximity sensor having electrodes  40 . Control circuitry  20  may include circuitry for dynamically configuring electrodes  40  and using electrodes  40  in making capacitive proximity sensor measurements. For example, control circuitry may include capacitive proximity 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 proximity sensor electrodes  40  may include reference electrodes  42  and sense electrodes  44  and/or other electrode structures. Switch  20 A- 1  may be dynamically configured based on control signals from controller  20 B so that capacitive proximity sensor measurements can be gathered with a desired configuration of electrodes  40 . In one mode of operation, each of reference electrodes  42  and each corresponding sense electrode  44  may be used in making a separate capacitive proximity sensor measurement. This maximizes detection spatial resolution. In other modes of operations, switch  20 A- 1  may be configured to couple together sets of electrodes to enhance detection range. In these operating modes, sets of two or more sense electrodes are shorted together while gathering sensor data. The electrodes that are shorted together in this way serve as unitary electrodes of increased size, which enhances proximity detection sensitivity. 
     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., 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 to buttons, touch sensors, 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 proximity sensor formed from each array of electrodes  40  may be dynamically configured to help device  10  determine the orientation of device  10  with respect to the user&#39;s head or other body part. For example, capacitive electrodes  40  may be dynamically combined to extend proximity sensing range and may be dynamically separated to increase capacitive proximity sensor resolution, thereby helping device  10  to identify which ear cup of a pair of headphones is covering the right ear of the user and which ear cup is covering the left ear. 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, 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 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 perspective 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. 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  through which sound may be emitted from a speaker (e.g., a speaker system with one or more drivers). User-facing ear cup surfaces  36  on 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 on the ear-facing surface  36  of one or both ear cups. 
     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 enhanced aesthetics. 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 proximity sensors on inwardly facing (ear-facing) surfaces  36  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. An illustrative pattern of electrodes  40  that may be used on each ear cup inner surface  36  is shown in  FIG. 3 . In the example of  FIG. 3 , each electrode (A 1  . . . A 8 , B 1  . . . B 8 , and C) corresponds to a sense electrode  44  and corresponding reference electrode  42  and can be used independently or in a configuration in which two or more electrodes are joined together to enhance detection sensitivity. Electrodes  40  can be arranged in a circular-type pattern (e.g., a circular array in which some or all of the electrodes are arranged in a ring around a center point) and/or other shapes that are suitable for gathering information from the ears of a user. 
     A diagram of an illustrative ear of a user is shown in  FIG. 4 . As shown in  FIG. 4 , ear  46  may have points such as points P 1 , P 2 , and P 3  that may be sensed by a capacitive proximity sensor. These points are distributed asymmetrically so that the pattern of points P 1 , P 2 , and P 3  that is measured will indicate whether ear  46  is a right ear or a left ear. Some portions of ear  46  such as portion VR may be recessed with respect to prominent points such as points P 1 , P 2 , and P 3 . Portions such as portion VR may be measured by dynamically reconfiguring the electrodes of the capacitive proximity sensor to enhance the detection range of the sensor in portion VR relative to portions of ear  46  in the vicinity of points P 1 , P 2 , and P 3 . 
       FIG. 5  is a graph showing how sensor electrodes of different sizes exhibit different measurement sensitivities. In the graph of  FIG. 5 , sensor output has been plotted as a function of distance to an external object that is being sensed. Curve  50  is representative of a sensor electrode of a first size. The maximum detection range of an electrode of this first size is D 1 , due to the presence of system noise MN. Curve  48  is representative of a sensor electrode of a second size that is larger than the first given size. As indicated by curve  48 , a sensor with an enlarged capacitive electrode size can detect objects at a larger maximum distance (e.g., distance D 2 , which is larger than D 1 ) before being limited by noise MN. Larger sensor electrode sizes exhibit reduced amounts of spatial resolution. To make satisfactory measurements on the ear&#39;s of a user or other external object, device  10  may dynamically configure electrodes  40  into multiple different operating modes. The operating modes may include one or more modes that favor enhanced spatial resolution over detection range and one or more modes that favor enhanced detection range over spatial resolution. By measurements made using these different modes, pattern recognition operations on external objects such as ear recognition operations may be enhanced. 
     Consider, as an example, the scenario of  FIG. 6 , in which a capacitive proximity sensor in device  10  is using electrodes  40  to make proximity sensor measurements on ear  46 . As shown in the cross-sectional side view of  FIG. 6 , ear  46  may have portions such as portions P 1  and P 2  that are at a first distance ZL from electrodes  40  (e.g., from sense electrodes  44 ) and may have other portions such as portion VR that are located at a second distance ZB from electrodes  40  (e.g., from electrodes  44 ). Distance ZB is larger than distance ZL. To enhance the sensitivity of the capacitive proximity sensor of device  10  to enable satisfactory measurements at larger distances such as distance ZL, multiple electrodes  44  can be dynamically configured to operate together and thereby serve as a unitary electrode  44 ′ of enlarged area. As described in connection with  FIG. 5 , the use of larger electrodes each of which is formed from set of smaller combined electrodes (e.g., using electrode  44 ′ in place of a pair of smaller electrodes  44 ) enhances the ability of device  10  to detect ear  46  in region VR by extending the sensitivity of the capacitive proximity sensor adjacent to region VR relative to the sensitivity of the capacitive proximity sensor in regions in which only smaller electrodes  44  are independently used. 
       FIG. 7  is a cross-sectional side view of illustrative capacitive proximity sensor electrodes  40 . As shown in the illustrative configuration of  FIG. 7 , electrodes  40  may include sense electrodes  44  supported on a first surface of substrate  54  and corresponding reference electrodes  42  on an opposing second surface of substrate  54 . Interconnections  52  may be used in routing signals between electrodes  40  and control circuitry  20 . Interconnects  52  may be formed on one or both surfaces of substrate  54  and/or may be embedded within substrate  54 . Control circuitry  20  may include one or more integrated circuits mounted to substrate  54  or mounted to one or more separate substrates electrically coupled to substrate  54 . Control circuitry  20  may be located in one of ear cups  30 , in both ear cups  30  and/or elsewhere in device  10 . Electrodes  40  may be formed from metal (e.g., metal traces deposited using techniques such as physical vapor deposition, chemical vapor deposition, electrochemical deposition techniques such as electroplating and electroless deposition, printing of metal paint, etc.). Interconnects  52  may be metal signal traces in a printed circuit or other conductive paths. Substrate  54  may be a printed circuit such as a flexible printed circuit formed from a sheet of polyimide or other flexible dielectric or a rigid printed circuit board formed from rigid printed circuit board material such as fiberglass-filled epoxy or may be a substrate formed from other suitable dielectric substrate materials. 
     To accommodate acoustic signals, electrodes  40  may be provided with openings such as openings  58  in illustrative sensor electrode  56  of  FIG. 8 . Openings  58  may be circular, may be rectangular, may be arranged in an array, and/or may have other suitable shapes and patterns. Electrodes such as electrode  56  of  FIG. 8  may be used in forming electrodes  44  and/or electrodes  42 . For example, a first electrode with sound passageway openings may be formed on a first side of a printed circuit substrate and a second electrode with sound passageway openings may be formed on a second side of a printed circuit substrate to form an array of electrodes  40  (e.g., electrodes having a ring-shaped layout of the type shown in  FIG. 3  or other suitable pattern of sensor electrodes). The sound passageways of electrodes  40  may be aligned with openings in substrate  54  and openings in other stacked layers of material in device  10 , thereby allowing sound from a speaker in each ear cup to pass to the ear of a user. 
     A cross-sectional side view of device  10  showing how the structures of device  10  (e.g., each of ear cups  30 ) may be provided with acoustic passageways such as circular through-holes or other openings is shown in  FIG. 9 . As shown in  FIG. 9 , ear cup  30  may have an interior portion (e.g., a cavity) such as interior  62 . Speaker  24  may be mounted in interior  62  and may provide sound to ear  46  through acoustic passageways formed from the layers of material interposed between ear-facing surface  36  and speaker  24 . Rear housing wall  60  may be formed from one or more structures such as a plastic housing member, fabric layers, layers of plastic, leather, or other materials, and/or other housing structures. 
     Layer  74  may be formed from fabric. Layer  74  may, for example, be formed from a fabric in which strands of material  74 F such as plastic or natural yarns have been intertwined using weaving, knitting, braiding, or other fiber intertwining techniques. The intertwining process used to form layer  74  may configure layer  74  so that sound may pass through layer  74  without significant attenuation. If desired, other layers of material may be used in forming the outermost layer of material under surface  36  (e.g., wire or plastic meshes, open cell plastic foam, natural materials with openings such as perforated leather, perforated plastic, etc.). The use of a layer of fabric to form layer  74  is illustrative. 
     If desired, ear cup  30  may have multiple layers of fabric. For example, additional fabric layer  72  with strands of material such as strands  72 F may be formed under layer  74 . As with layer  74 , the density of fibers in layer  72  is preferably sufficiently low to create acoustic passageways (air-filled passageways) through layer  72  so that sound from speaker  24  can pass to ear  46  without being overly attenuated. With one illustrative configuration, outer layer  74  is formed from a finely woven fabric and inner layer  72  is formed from a more coarsely woven fabric. Other fabric arrangements (e.g., arrangements with only a single layer of fabric such as a layer of fabric into which fine and/or coarse portions have been woven, arrangements with three or more layers of fabric, etc.) may also be used. 
     Under layer  72 , ear cup  30  may include a protective structural layer such as mesh layer  70 . Mesh layer  70  may be formed from a layer of plastic, metal, or other material with openings such as openings  70 H. Openings  70 H may be formed in an array with a sufficient density to allow sound from speaker  24  to pass through layer  70  without significant attenuation. The presence of layer  70  may help strengthen ear cup  30  (e.g., to prevent inadvertent damage from puncturing of the ear cup with a foreign object, etc.). If desired, layers of open-cell foam and/or other material may be incorporated into ear cup  30  under layer  74 . The example of  FIG. 9  is illustrative. 
     In the arrangement of  FIG. 9 , mesh layer  70  overlaps sensors electrodes  40 . Electrodes  40  may be formed in an array in which sense electrodes  44  are formed on a first side (e.g., an ear-facing side) of substrate  54  and in which corresponding reference electrodes  42  are formed on an opposing side (e.g., a speaker-facing side) of substrate  54 . As described in connection with  FIG. 8 , electrodes  44  may have acoustic openings  44 H and electrodes  42  may have acoustic openings  42 H (e.g., first and second respective sets of aligned openings). These overlapping openings may be aligned with corresponding overlapping openings  54 H in substrate  54  to allow sound from speaker  24  to pass to ear  46 . 
     Configurations of the type shown in  FIG. 9  allow sound from speaker  24  to reach the ears of a user while allowing control circuitry  20  to use the capacitive proximity sensor formed from electrodes  40  in making measurements on the shape of the user&#39;s ears (e.g., in detecting left and right user ear patterns). This allows control circuitry  20  to detect the orientation of device  10  on the head (ears) of a user. Based on the detected orientation, control circuitry  20  can configure its audio circuitry (e.g., left and right audio amplifiers coupled to speakers  24 ) so that left channel audio and right channel audio are routed appropriately to a user&#39;s ears. 
     If desired, additional structures may be formed in ear cup  30  such as one or more additional layers of material overlapping speaker  24  and/or electrodes  40 , additional cosmetic and/or protective layers, etc. 
       FIG. 10  is a flow chart of illustrative operations involved in using device  10 . 
     During the operations of block  80 , control circuitry  20  may monitor sensors  26  to determine whether device  10  is being used by a user. Control circuitry  20  may, for example, gather motion data using an accelerometer and may compare this motion data to a predetermined motion threshold. If the motion information from sensors  26  indicates that device  10  is in motion (e.g., if motion readings exceed a predetermined threshold), control circuitry  20  may conclude that a user is using device  10 . In response to detecting that device  10  is in motion and in use, control circuitry  20  may awaken device  10  from a low-power sleep state and may proceed to make proximity sensor measurements to determine the orientation of device  10  on the head of a user. 
     During the operations of block  82 , control circuitry  20  may, for example, place the array of electrodes  40  in device  10  in a first operating mode appropriate for detecting whether ears  46  are present adjacent to surfaces  36 . Electrodes  40  may have a circular layout of the type shown in  FIG. 3  or other suitable layout. Control circuitry  20  (e.g., controller  20 B) may control capacitive sensing circuit  20 A- 2  and switch  20 A- 1  so that one or more sets of multiple electrodes  40  are combined to enhance external object detection range while device  10  is operated in the first mode. Control circuitry  20  may, as an example, use switch  20 A- 1  to short multiple electrodes together such as electrodes A 1 -A 6  and B 1 -B 6  and/or all of the electrodes  40  in the array of electrodes  40  in each ear cup  30  so that these electrodes serve as a larger unitary electrode in each ear cup  30  (e.g., a maximum area electrode that may be used in detecting external objects with a corresponding maximized detection range). Configurations in which fewer than all electrodes  40  are coupled together using switch  20 A- 1  may also be used. 
     While operating in the first capacitive proximity sensor configuration (e.g., the first operating mode of block  82 ), control circuitry  20  (e.g., capacitive sensing circuit  20 A- 2 ) may monitor electrodes  40  for the presence of an external object such as an ear of the user. In response to detecting no object for a predetermined time period (e.g., in response to failing to detect any output of the capacitive sensing circuit that passes a predetermined threshold amount within a predetermined amount of time such as 10 s, at least 2 s, less than 30 s, or other suitable timeout time period), control circuitry  20  (e.g., controller  20 B) may place device  10  (e.g., control circuitry  20 ) in a low-power sleep state and operations may return to block  80 . In response to detecting that an external object is in the vicinity of surface  36  (e.g., within 1-3 cm, within less than 3 cm, within at least 1 mm, or other suitable range of surface  36 ), control circuitry  20  may place device  10  in a second operating mode (see, e.g., the operations of block  84 ). 
     While operating in the second mode (block  84 ), control circuitry  40  may configure the array of electrodes  40  in device  10  so that fewer electrodes are combined together than in the first operating mode. With one illustrative configuration, some of electrodes  40  are coupled together in pairs or in sets of three or more electrodes to enhance detection range, whereas other electrodes  40  are used individually. With another illustrative configuration, all of electrodes  40  are coupled together in pairs or in sets of three or in sets of four or more electrodes. Regardless of the particular electrode configuration created by control circuitry  20  using switch  20 A- 1 , at least some of the unitary electrode(s) of the first mode are divided into more granular electrodes, so spatial resolution is enhanced in the second mode relative to the first mode, while detection range is decreased. This allows device  10  to more clearly identify ear shapes in the second mode than in the first mode. An ear shape measurement in the second operation mode may, for example, be sufficient in spatial resolution to discriminate between a pattern associated with a left ear and a pattern associated with a right ear. If desired, control circuitry  20  can place electrodes  40  in one or more additional configurations to further enhance spatial resolution and thereby make more detailed proximity measurements to further confirm whether a measured ear pattern corresponds to a right or left ear. Control circuitry  20  may, as an example, place device  10  in a third operating mode in which switch  20 A- 1  couples each of electrodes  44  to capacitive sensing circuit  20 A- 2  individually so that capacitive proximity sensor measurements of maximum spatial resolution may be obtained (at minimum detection range). The measurements made in the optional third mode N may be used in confirming detection of a left or right ear (e.g., these measurements may be used to enhance the accuracy of the left/right ear determination measurements made while operating the capacitive proximity sensor in the second operating mode). In modes such as the first, second, and third operating modes, control circuitry  20  can use switch  20 A- 1  to sequentially step through each set of electrodes of interest, so that measurements can be systematically gathered form all electrodes  40  of interest. Configurations in which parallel sensor electrode measurements are gathered by control circuitry  20  may also be used, if desired. 
     If no external objects are detected during the operations of block  84 , control circuitry  20  may place device  10  in a low-power sleep state and may return to the operations of block  80 . If an external object is detected by the capacitive proximity sensor but no left or right ear pattern is detected, control circuitry  20  can conclude that a user&#39;s hand or other external object other than a human ear is present in the vicinity of surface  36 . Control circuitry  20  can therefore wait during the operations of block  36  (e.g., for a time period of at least 1 s, 1-20 s, less than 30 s, or other suitable time period) before looping back to block  84  to gather additional sensor measurements. If desired, control circuitry  20  may impose the wait of block  86  in response to other types of measurements such as when measurements indicate a fault condition (e.g., if two right ears are detected, if two left ears are detected, or if only a single ear is detected even though objects are present at both ear cup surfaces  36 ). 
     In response to detection in each ear cup  30  of a left or right ear (or at least one ear in one ear cup), device  10  may take appropriate actions at block  88 . During the operations of block  88 , control circuitry  20  may, for example, fully power up the circuitry of device  10  (e.g., by turning on audio amplifier circuitry in control circuitry  20 , by turning on wireless communications circuitry in device  10  and establishing wireless link  28  with device  10 ′, etc.). 
     The audio amplifier circuitry in control circuitry  20  may be configured in response to the detected orientation of device  10  on the ears of a user. For example, left channel audio can be routed to the speaker in the ear cup at which the user&#39;s left ear has been detected and right channel audio can be routed to the speaker in the ear cup at which the user&#39;s right ear has been detected. Audio playback operations with this set of ear cup assignments may then be performed so that a user can automatically enjoy stereo audio without experiencing undesired reversed audio channel assignments. During normal operations at block  88 , control circuitry  20  can monitor input-output devices  22  and take appropriate actions. For example, control circuitry  20  can monitor an accelerometer, compass, gyroscope, or other orientation sensor circuitry to measure the orientation of device  10  as the position of the user&#39;s head shifts, can use buttons and other input devices to gather user input, and/or can gather other information about the operating environment of device  10  and user input commands being supplied to device  10 . Based on this information, audio playback operations and/or other system functions can be adjusted (e.g., playback volume, left/right balance, bass/treble settings, surround sound mode, etc.). 
     Normal device operations at block  88  may also involve periodically determining whether control circuitry  20  should make additional proximity sensor measurements. For example, a timer may expire, a lack of movement may be detected, or other conditions may arise that indicate to control circuitry  20  that processing should loop back to block  84  to gather proximity sensor measurements (e.g., maintenance measurements) and thereby confirm previous ear pattern recognition results. During these maintenance measurements, control circuitry may operate the capacitive proximity sensor(s) in device  10  in sensor modes such as the second and/or third operating modes and/or in additional maintenance modes. Sensor sensitivity may be calibrated during maintenance operations and/or ear presence may be confirmed. If control circuitry  20  senses that the operating status of device  10  has changed (e.g., if the orientation of device  10  on the ears of the user has been reversed or if device  10  is no longer being worn by the user), control circuitry  20  can take appropriate action by updating the channel assignments at block  88  or returning to block  80 , respectively. 
     
       
         
           
               
             
               
                   
               
               
                 Table of Reference Numerals 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                 10 
                 electronic device 
                 10′ 
                 external equipment 
               
               
                 20 
                 control circuitry 
                 20A-1 
                 switching circuitry 
               
               
                 20A-2 
                 capacitive sensing 
                 20B 
                 controller 
               
               
                   
                 circuitry 
               
               
                 22 
                 input-output devices 
                 24 
                 speaker 
               
               
                 26 
                 sensor elements 
                 28 
                 wireless link 
               
               
                 30 
                 ear cups 
                 32 
                 area 
               
               
                 34 
                 band 
                 36 
                 user-facing ear cup 
               
               
                   
                   
                   
                 surfaces 
               
               
                 40 
                 capacitive proximity 
                 42 
                 reference electrodes 
               
               
                   
                 sensor electrodes 
               
               
                 42H 
                 acoustic openings 
                 44 
                 sense electrodes 
               
               
                 44′ 
                 unitary electrode 
                 44H 
                 acoustic openings 
               
               
                 46 
                 ear 
                 48 
                 curve 
               
               
                 50 
                 curve 
                 52 
                 interconnects 
               
               
                 54 
                 substrate 
                 54H 
                 overlapping openings 
               
               
                 56 
                 illustrative sensor 
                 58 
                 openings 
               
               
                   
                 electrode 
               
               
                 60 
                 rear housing wall 
                 62 
                 interior 
               
               
                 70 
                 mesh layer 
                 70H 
                 openings 
               
               
                 72 
                 layer 
                 72F 
                 strands 
               
               
                 74 
                 layer 
                 74F 
                 material 
               
               
                 80 
                 block 
                 82 
                 block 
               
               
                 84 
                 block 
                 86 
                 block 
               
               
                 88 
                 block 
                 A1 . . . A8 
                 sense electrodes 
               
               
                 B1 . . . B8 
                 sense electrodes 
                 C 
                 sense electrodes 
               
               
                 D1 
                 maximum detection 
                 D2 
                 distance 
               
               
                   
                 range 
               
               
                 MN 
                 system noise 
                 P1 
                 point 
               
               
                 P2 
                 point 
                 P3 
                 point 
               
               
                 VR 
                 portion 
                 ZB 
                 distance 
               
               
                 ZL 
                 distance 
               
               
                   
               
            
           
         
       
     
     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: 20171109
Publication Date: 20190514
Grant Date: 20190514
Priority Date: 20170331
Inventors: PETERSON, JONATHAN R.
Bunney, Jr., Mark A.
Assignee: APPLE INC
CPC Classifications: [{"code": "H04R1/1008", "inventive": true, "first": false, "tree": "[]"}, {"code": "H03K17/955", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01P15/0802", "inventive": false, "first": false, "tree": "[]"}, {"code": "G01P15/08", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R1/1041", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F1/3231", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01D5/241", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R5/033", "inventive": false, "first": false, "tree": "[]"}, {"code": "G01D5/241", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01D5/241", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0487", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R5/033", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R1/1008", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01P15/08", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/3231", "inventive": true, "first": false, "tree": "[]"}, {"code": "H03K17/955", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0487", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/1008", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01P15/08", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R1/1041", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R5/033", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R1/1041", "inventive": true, "first": true, "tree": "[]"}, {"code": "G01P15/0802", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 63670119