Wearable Audio Device Placement Detection

Abstract

1. An earphone comprising: an electro-acoustic transducer for generating sound; a proximity sensor configured to detect when the earphone is in proximity to a user's skin; an orientation sensor configured to detect an orientation of the earphone; and a processor configured to estimate whether the earphone is inserted in a user's ear canal based on the proximity sensor and the orientation sensor.

Description

[Technical Field]

[0001] The present disclosure relates to wearable audio devices. [Background technology]

[0002] Wearable audio devices are designed to function best when they are in the proper position for use on the body and when the user has stopped manipulating the device. Summary of the Invention [Means for solving the problem]

[0003] All examples and features mentioned below can be combined in any technically possible manner.

[0004] In one aspect, a wearable audio device includes an electro-acoustic transducer for generating sound; a proximity sensor configured to detect when the wearable audio device is in proximity to a user; an orientation sensor configured to detect an orientation of the wearable audio device; an internal microphone positioned within a housing of the wearable audio device and configured to detect sound within a cavity formed at least in part by a portion of the housing; and a processor configured to estimate (i) whether the wearable audio device is in place on a user's body based on the proximity sensor and the orientation sensor, and (ii) whether the user has completed operating the wearable audio device based on the internal microphone.

[0005] Some embodiments include one of the above and / or below features, or any combination thereof. In one embodiment, the proximity sensor includes an infrared sensor. In one embodiment, the orientation sensor includes an inertial measurement unit (IMU). In one embodiment, the IMU comprises an accelerometer used to detect the orientation of the wearable audio device. In one embodiment, the proximity sensor has an output, and an estimation by the processor of whether the wearable audio device is in place on the user's body is based in part on a level of the proximity sensor output. In one embodiment, after the processor estimates whether the wearable audio device is in place on the user's body, the processor is configured to enable predetermined wearable audio device functions. In one embodiment, the predetermined wearable audio device functions include at least one of phone answering capability, Bluetooth connectivity, beamforming of microphones carried by the wearable audio device, playing audio received from an external audio source, enabling user interface functions, and tuning an active noise reduction system.

[0006] Some embodiments include one of the above and / or below features, or any combination thereof. In some embodiments, the wearable audio device further comprises an external microphone configured to sense sound outside the housing, and the processor's estimation of whether the wearable audio device is in place on the user's body is further based on a transfer function between the external microphone and the internal microphone. In one embodiment, the processor is further configured to cause the electro-acoustic transducer to generate sound upon which the transfer function is based. In one embodiment, the transfer function is determined at a frequency of up to 1,000 Hz. In one embodiment, the processor is further configured to cause the electro-acoustic transducer to generate sound at two different frequencies, the first frequency being at least 1,500 Hz, and the processor being configured to determine whether the wearable audio device nozzle is blocked based at least in part on the first frequency, and the second frequency being less than or equal to 1,000 Hz, and the processor being configured to determine whether the wearable audio device is in place on the user's body based at least in part on the second frequency.

[0007] Some embodiments include one of the above and / or below features, or any combination thereof. In one embodiment, the generated sound is part of a wearable audio device activation tone sequence. In one embodiment, the processor's estimation of whether the wearable audio device is in place on the user's body includes two consecutive steps: a first step based on at least a proximity sensor, an orientation sensor, and an internal microphone, and a second step based on at least the internal microphone and an external microphone. In some embodiments, the processor is configured to initiate a first group of wearable audio device functions based on the first step and a second group of wearable audio device functions based on the second step, wherein the functions of the second group are different from the functions of the first group. In one embodiment, the functions of the first and second groups include at least one of phone answering capability, Bluetooth connectivity, beamforming of microphones carried by the wearable audio device, playing audio received from an external audio source, enabling user interface functions, and tuning an active noise reduction system. In one embodiment, during at least the first step, the internal microphone is monitored at a frequency in the range of 0-20 Hz.

[0008] In another aspect, a method for detecting when a wearable audio device is in place on a user's body, the wearable audio device comprising: an electro-acoustic transducer for generating sound; a proximity sensor configured to detect when the wearable audio device is in proximity to a user; an orientation sensor configured to detect an orientation of the wearable audio device; an internal microphone positioned within a housing of the wearable audio device and configured to detect sound within a cavity formed at least in part by a portion of the housing; and an external microphone configured to sense sound outside the housing, the method including estimating whether the wearable audio device is in place on the user's body based on the proximity sensor, the orientation sensor, and the internal microphone; and estimating whether the user has completed operating the wearable audio device based on the internal microphone.

[0009] Some embodiments include one of the above and / or below features, or any combination thereof. In one embodiment, the processor is further configured to cause the electro-acoustic transducer to generate sound after the processor estimates that the wearable audio device is in place on the user's body, and the processor is further configured to calculate a transfer function between the external microphone and the internal microphone over a specified frequency or frequency range of the generated sound. In one embodiment, the processor's estimation of whether the wearable audio device is in place on the user's body includes two consecutive steps: a first step based on at least the proximity sensor, the orientation sensor, and the internal microphone, and a second step based on at least the internal microphone and the external microphone, and the processor is configured to initiate a first group of wearable audio device functions based on the first step and a second group of wearable audio device functions based on the second step, wherein the functions of the second group are different from the functions of the first group. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view of a wearable audio device. [Figure 2] FIG. 2 is a partial cross-sectional view of a wearable audio device. [Figure 3] 10 is a flowchart of the operation of an earphone placement detection method. [Figure 4] 1 shows the transfer function between the earphone external microphone and the internal microphone when the earphone is located in free space and in the ear. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present disclosure relates to wearable audio devices. Some non-limiting examples of the present disclosure describe a type of wearable audio device known as an earphone. An earphone generally includes an electro-acoustic transducer for generating sound and is configured to deliver sound directly to a user's ear canal. Earphones can be wireless or wired. In the examples described herein, the earphones are wireless and therefore include a power source (typically a rechargeable battery), a wireless communication system (in one example, a Bluetooth-based communication system), and any necessary processing. Other aspects of the earphones not included in this disclosure are not shown or described.

[0012] Some embodiments of the present disclosure also describe a type of wearable audio device known as an open-type audio device. Open-type audio devices have one or more electro-acoustic transducers (i.e., audio drivers) located away from the ear canal opening. In some embodiments, the open-type audio device also includes one or more microphones, which may be used to pick up the user's voice and / or for noise cancellation. Open-type audio devices are further described in U.S. Pat. No. 10,397,681, the entire disclosure of which is incorporated herein by reference for all purposes.

[0013] Headphones typically refer to devices worn around, on, or in the ear and radiate acoustic energy directly or indirectly into the ear canal. Headphones are sometimes referred to as earphones, earpieces, headsets, earbuds, or sports headphones and can be wired or wireless. Headphones contain an electro-acoustic transducer (driver) that converts audio signals into acoustic energy. The acoustic driver may or may not be housed in an earcup or housing configured to be positioned on the head or ear, or inserted directly into the user's ear canal. A headphone may be a single, standalone unit, one for each ear, or one of a pair of headphones (each containing at least one acoustic driver). A headphone may be mechanically connected to another headphone, for example, by a headband and / or by leads that carry audio signals to the acoustic driver in the headphone. Headphones may include components for wirelessly receiving audio signals. Headphones may include components for an active noise reduction (ANR) system, which may include an internal microphone within the headphone housing. The headphones may also include other features, such as an additional microphone for an ANR system, or one or more microphones used to pick up the user's voice.

[0014] In around-ear headphones, on-ear headphones, or off-ear headphones, the headphones may include a headband or other support structure and / or at least one housing or other structure that houses the transducers and is positioned to rest on, above, or adjacent to the user's ears. The headband may be foldable or collapsible and may be made in multiple pieces. Some headbands include a slider, which may be located inside the headband to provide any desired translation of the housing. Some headphones include a yoke pivotally attached to the headband, with the housing pivotally attached to the yoke to provide any desired rotation of the housing.

[0015] Open-type audio devices include, but are not limited to, off-ear headphones, i.e., devices having one or more electro-acoustic transducers that are coupled to the head or ear (typically by a support structure) but do not occlude the ear canal opening. In some examples, open-type audio devices are off-ear headphones with audio glasses, although this is not a limitation of the present disclosure, as in open-type audio devices, the device is configured to deliver sound to one or both ears of the wearer, typically without earcups or earbuds. Wearable audio systems contemplated herein may include a variety of devices, including over-ear hooks, such as wireless headsets, hearing aids, eyeglasses, protective helmets, and other open-ear audio devices.

[0016] One or more of the devices, systems, and methods described herein may be used in various embodiments and combinations in a wide variety of wearable audio devices or systems, including wearable audio devices of various form factors. Unless otherwise specified, the term active part of a wearable audio system as used in this document includes headphones and various other types of wearable audio devices, such as head-, shoulder-, or body-worn acoustic devices (e.g., audio glasses or other head-mounted audio devices), which include another acoustic transducer for receiving and / or generating sound with or without contact with the user's ear.

[0017] While specific implementations of wearable audio devices primarily serving the purpose of acoustically outputting audio have been presented in some detail, it should be noted that the presentation of such specific implementations is intended to facilitate understanding through the provision of examples and should not be construed as limiting either the scope of the disclosure or the claims.

[0018] In some examples, the wearable audio device includes a proximity sensor configured to detect when the earbuds are in proximity to a user. In one example, the proximity sensor detects the user's skin. In one example, the proximity sensor is an infrared (IR) sensor that can detect when the wearable audio device is in proximity to or in contact with the skin of the ear. In one example, the IR sensor output is within a predetermined range or at least a predetermined threshold level for a position-of-use determination to be made. In some examples, the wearable audio device also includes an orientation sensor configured to detect the orientation of the wearable audio device. In one example, the orientation is determined in three mutually orthogonal axes in space. Because wearable audio devices are designed to be worn in a specific orientation, knowing the orientation via the orientation sensor can indicate whether the device is in place. For example, when the earbuds are held in the ears of an upright head, the internal orientation sensor has a known orientation in three-dimensional space. The resulting value of the orientation sensor can be within a nominal predetermined range for a position-of-use determination to be made. The wearable audio device further includes a processor configured to estimate, based on the proximity sensor and the orientation sensor, whether the wearable audio device is in the right place on the user's body. In some examples where the wearable audio device is an earphone, the right place is within the user's ear canal.

[0019] In some examples, the wearable audio device also includes an internal microphone. In one example, the internal microphone is positioned within a housing of the wearable audio device. In one example, the microphone is positioned to detect sound within a cavity formed at least in part by a portion of the housing. When the internal microphone is used within the wearable audio device, the processor may also be configured to estimate whether a user has completed operation of the wearable audio device. In some examples, operation includes placing the wearable audio device in position on the body or removing it from the body. In some examples, the wearable audio device also includes an external microphone. In one example, the external microphone is positioned to detect sound outside the wearable audio device housing. When the external microphone is used within the wearable audio device, the processor may also be configured to calculate an audio transfer function between the internal microphone and the external microphone and estimate whether the wearable audio device is in its appropriate use position (e.g., in-ear) based on the transfer function.

[0020] FIG. 1 is a perspective view of a wireless in-ear earphone 10. An earphone is a non-limiting example of a wearable audio device. Earphone 10 includes a body or housing 12 that houses the active components of the earphone. Portion 14 is coupled to body 12 and is flexible so that it can be inserted into the entrance of the ear canal. Sound is delivered through opening 15. Retention loop 16 is configured and arranged to be positioned within the outer ear, e.g., within the antihelix, to help retain the earphone in the ear. Earphones are known in the art (e.g., as disclosed in U.S. Pat. No. 9,854,345, the disclosure of which is incorporated herein by reference in its entirety for all purposes), and therefore, specific details of earphones will not be further described herein.

[0021] FIG. 2 is a partial cross-sectional view of only certain elements of earphone 20 that is useful for better understanding the present disclosure. Earphone 20 includes housing 21 that encloses electro-acoustic transducer (audio driver) 30. Housing 21 includes front housing portion 50 and rear housing portions 60 and 62. Transducer 30 has a diaphragm 32 that is driven to create sound pressure within front cavity 52. ​​The sound pressure is directed outward from front housing portion 50 through sound outlet 54. An internal microphone 80 is located inside housing 21. In one embodiment, microphone 80 is located within sound outlet 54, as shown in FIG. 2. An external microphone 81 is configured to sense sound outside of housing 21. In one embodiment, internal microphone 80 is used as a feedback microphone for active noise reduction, and external microphone 81 is used as a feedforward microphone for active noise reduction. 1 typically includes a flexible tip (not shown) that engages with neck 51 of housing portion 50 to help direct sound into the ear canal. Earphone housing 21 further includes a rear enclosure made from rear housing portions 60 and 62, and a grill 64. Note that the details of earphone 20 are exemplary embodiments of earphones and are not intended to limit the scope of the present disclosure, as this in-ear detection can be used in various types and designs of earbuds and earphones, as well as other wearable audio devices.

[0022] Transducer 30 further comprises a magnetic structure 34. Magnetic structure 34 includes a transducer magnet 38 and magnetic material that functions to contain and guide the magnetic field from magnet 38 so that it appropriately interacts with coil 33 to drive diaphragm 32, as is well known in the art of electro-acoustic transducers. The magnetic material includes cup 36 and front plate 35, both of which are preferably made from a material with relatively high magnetic susceptibility, also as is known in the art. Transducer printed circuit board (PCB) 40 carries the electrical and electronic components (not shown) responsible for driving the transducer. Pads 41 and 42 are locations where wires (not shown) can be coupled to PCB 40.

[0023] In one embodiment, an inertial measurement unit (IMU) 72 is used to detect the orientation of the earphones in three-dimensional space. The IMU can include a three-axis accelerometer that can be used to determine orientation. The use of accelerometers to determine the orientation of devices that include or carry accelerometers is known in the art and therefore will not be described further herein. The IMU can also include a gyroscope or three gyroscopes configured to determine the rate of rotation about three mutually orthogonal axes. The gyroscopes can additionally or alternatively be used to determine the orientation of the earphones. The use of gyroscopes to determine the orientation of devices that include or carry gyroscopes is known in the art and therefore will not be described further herein. In one embodiment, the IMU 72 is mounted on the PCB 70, although the IMU may be located elsewhere within or on the earphones.

[0024] In some embodiments, proximity sensor 76 is used to detect the proximity of earphone 20 to the user's skin. In one embodiment, proximity sensor 76 can be an infrared (IR) sensor or a capacitive sensor. An IR sensor can be used to detect proximity to the skin, while a capacitive sensor can detect when the device is touching the skin. The IR sensor can be used to detect the proximity of the earphone to the skin. Because the earphone must be in the ear when in the proper use position, parts of the earphone are in contact with or near the skin. Therefore, positioning the IR sensor on a part of the earphone that is in contact with or near the skin allows the IR sensor to be used as a proximity sensor. In one embodiment, the IR sensor is positioned to detect the tragus. In another example, a distance sensor, such as a time-of-flight sensor, can be used to detect the distance between the wearable audio device and a desired location on the body (e.g., in the ear). When the wearable audio device is in place, the device is properly positioned at a known location on the body (e.g., in the ear, on the ear, or elsewhere on the head), so the distance from the device to the appropriate location should be zero or close to zero.

[0025] The earphones 20 also include a processor 74. In some embodiments, the processor 74 is configured to process the outputs of the IMU 72, the proximity sensor 76, the internal microphone 80, and the external microphone 81. As will be apparent to one skilled in the art, it is understood that the processor is typically involved in other processing necessary for earphone function, such as processing digital sound files played by the earphones. In one embodiment, the processor is configured to estimate whether the wearable audio device is in place on the user's body based on both the proximity sensor and the orientation sensor. In some examples, the processor's estimation of whether the wearable audio device is in place on the user's body is further based on a transfer function between the external microphone and the internal microphone. In one embodiment, the processor is configured to estimate whether the user has completed operating the wearable audio device based on the internal microphone. In some embodiments, the proximity sensor has an output, and the processor's estimation of whether the wearable audio device is in place on the user's body is based in part on the level of the proximity sensor output. In one embodiment, the processor's estimation of whether the wearable audio device is in place on the user's body is based in part on whether the proximity sensor output reaches a threshold level. For example, as the wearable audio device approaches the skin, the IR sensor output increases. For any particular IR sensor, output reaching a predetermined level can be considered equivalent to the sensor being within a predetermined distance from the skin.

[0026] In some examples, the processor's estimation of whether the wearable audio device is in place on the user's body includes multiple successive steps. In one example, a first step is based on a proximity sensor and an orientation sensor, a second step is based on an internal microphone, and a third step is based on the internal and external microphones. In one example, the processor is configured to initiate a first group of wearable audio device functions based on the first and second steps and a second group of wearable audio device functions based on the third step. In one example, the functions in the second group are different from the functions in the first group. In some examples, the functions in the first and second groups include at least one of phone answering capability, Bluetooth connectivity, beamforming of microphones carried by the wearable audio device, playback of audio received from an external audio source, activation of user interface functions, and tuning of an active noise reduction system.

[0027] In some embodiments, the processor is configured to cause the electro-acoustic transducer to generate a sound for use in a high-confidence determination of whether the wearable audio device is in place. In one embodiment, this high-confidence determination is made only after the processor makes a first level low-confidence determination that the wearable audio device is in place on the user's body and the user has stopped manipulating the device. In one embodiment, the processor is configured to calculate a transfer function between the external microphone and the internal microphone over a specified frequency range. In one embodiment, the generated sound is part of a wearable audio device activation tone sequence.

[0028] In one embodiment, the processor is configured to cause the electro-acoustic transducer to generate sounds at two (or more) different frequencies for proper / improper location determination. In one embodiment, the first frequency is at least 1,500 Hz (e.g., 1,500-3,000 Hz), and the processor is configured to determine whether the wearable audio device nozzle is blocked based at least in part on the frequency. In one embodiment, the second frequency is less than 1,000 Hz, and the processor is configured to determine whether the wearable audio device is in the proper position on the user's body based at least in part on the frequency. When frequencies or frequency ranges are described herein, it should be understood that the frequencies or ranges are often approximate. When a particular frequency is specified, it should be understood that the actual frequency may be approximately or approximately the specified frequency. One reason is that even if the actual frequency differs from the stated frequency, the results may not be dramatically different.

[0029] Internal and external microphones may be used to detect sounds that are analyzed in different ways and for different purposes. There may be multiple functions for which microphones are used. One is to determine when a user is adjusting a wearable audio device. The internal microphone may be monitored for this function. In one embodiment, monitoring may be performed at frequencies up to 20 Hz, and the monitoring may be passive, i.e., the microphone is used to monitor sounds within the wearable audio device without using a driver to reproduce sound. If the wearable audio device is an earphone, the internal microphone may be a feedback microphone located within the earphone nozzle. When the earphone is operated (i.e., inserted into or removed from the ear), the operation produces sounds in the range up to 20 Hz. Therefore, detecting sounds in this range can be considered equivalent to detecting earphone operation. Also, when the earphone is inserted into the ear, the cavity bounded by the driver, earphone nozzle, ear canal, and eardrum is sealed, causing a DC pressure spike. The DC pressure spike occurs at 0 Hz but extends slightly within the frequency range. Therefore, monitoring the internal microphone in the 0-20 Hz range is useful for estimating when the earphones are inserted in the ears and / or when the earphones are no longer being operated.

[0030] A second function for which microphones can be used is to more reliably determine whether a wearable audio device is in the correct position on a user's body. Internal and external microphones can be used for this function. In one embodiment, an audio transfer function between an external microphone and an internal microphone is determined. This determination can be made at a frequency or frequency range where there is good transfer function magnitude value separation between the correct and incorrect locations (e.g., in-ear and out-of-ear earphones). In an earphone embodiment, the magnitude of the transfer function differs between in-ear and out-of-ear conditions at frequencies ranging from 0 to 1,000 Hz. Therefore, determining the transfer function in this frequency range can reliably indicate whether the earphone is in-ear or not. The same principle can be used for other types of earphones, headphones, and other types of wearable audio devices. The particular frequency or frequency range where there is good transfer function magnitude value separation between the correct and incorrect locations is unique for any given product. The determination of the "correct location" can then be made at a frequency or frequency range where there is good amplitude value separation.

[0031] Another function for which a microphone can be used is to determine whether the nozzle of an earphone is blocked. The earphone nozzle may be blocked by a finger when the earphone is being operated (e.g., when the earphone is in place in the ear or when it is removed from the ear). Therefore, a determination that the nozzle is blocked can be used as a less reliable indicator that the earphone is being operated and therefore not in the proper use position. In one example, in one frequency range, the audio transfer function between the external microphone and the internal microphone has one value when the nozzle is blocked by a finger and a different value when the wearable audio device is in free air or in the proper use position. For example, in the 1,500-3,000 Hz range, there is a different response when the earphone nozzle is blocked by a thumb compared to when the earphone is in the ear or outside the ear (which have similar responses). As another example, the transfer function of an earphone in the frequency range of 0-1,000 Hz may be low when the earphone is in free air and high when the nozzle is blocked (either by a finger or by the earphone being sealed in the ear canal). Thus, the transfer function may be an indicator that the earphone is being operated and an indicator that the earphone is in the ear. This determination may be used in conjunction with other determinations described herein to make a final determination as to whether the wearable audio device is in its proper use position.

[0032] FIG. 3 illustrates steps in a method 100 for detecting that a wearable audio device is in place on a user's body, as described above. In step 102, the proximity sensor is monitored for a proximity detection event. In step 104, the orientation sensor is monitored for proper orientation of the wearable audio device. In one embodiment, both sensors are monitored simultaneously. If the proximity sensor and orientation sensor reach thresholds indicating a possible in-ear event, the internal microphone is monitored in step 105. In one embodiment, the microphone is monitored in the 0-20 Hz range to detect that the wearable audio device is being operated by the user and that earbuds are inserted in the ears, as described elsewhere herein. Based on the monitoring of the proximity sensor, orientation sensor, and internal microphone, a low-confidence determination is made in step 106 as to whether the device is in the proper position (i.e., in the proper place on the user's body). In this non-limiting example, the device is an earbud, and therefore the determination is whether the device is in the proper in-ear position. If a low-confidence in-ear determination is made, a first group of earphone functions are enabled at step 108. In some embodiments, earphone functions that may be enabled based on this low-confidence determination include some or all of the following: automatic power on / off, automatic pause / play of audio, automatic phone answering function, Bluetooth connection / reconnection, beamforming of microphones carried by the wearable audio device, enabling user interface functions, and tuning of the active noise reduction system. More specifically, in one embodiment, the functions that are enabled after a low-confidence determination are background functions, such as turning on the processor, sensors, and Bluetooth. As a result, chips, sensors, and other aspects of the audio device that use power remain off until a first-level determination is made, thus conserving battery power.

[0033] Method 100 then proceeds to a second level of confidence determination that the earbud is in place in the ear. At step 110, the internal and external microphones are monitored. Next, at step 112, the driver is enabled to play one or more tones. The purpose of playing the tones is to receive the tones at the microphones and determine whether reception of the tones occurs, as would be expected if the wearable audio device were in the proper use position and the user had stopped manipulating the wearable audio device. In the earbud embodiment, the microphones used for this purpose include internal microphones used for feedback-based active noise reduction and external microphones used for feedforward-based active noise reduction. Both types of microphones are known in the field of active noise reduction for wearable audio devices and therefore will not be described further herein. Internal microphones are typically positioned so that they can sense sound within the cavity formed by the driver, earbud nozzle, and ear canal. An example is microphone 80 in FIG. 2. External microphones are capable of sensing sound outside the earbud housing. An example is microphone 81 in FIG. 2. In the method 100, at step 114, the transfer function (G sd ) is determined. G sdDetermining the head on / off state is described in U.S. Patent No. 10,462,551, entitled "Wearable Audio Device with Head On / Off State Detection," issued October 29, 2019, the entire disclosure of which is incorporated herein by reference for all purposes. The acoustic coupling from the driver to the microphone (exemplified by a transfer function) changes (at least at one or more frequencies) when the earphone is in-ear versus out-of-ear. In one example, the processor of the wearable audio device is configured to both cause the electro-acoustic transducer to generate sound and calculate the transfer function after the processor makes a first-level estimate that the wearable audio device is in place on the user's body. In one example, the transfer function is calculated over a specified frequency range, which may be in the range of 0 to 1,000 Hz. In some examples, the sound played is part of a device activation sequence of tones common in electronic devices.

[0034] If the transfer function is as expected, then a high-confidence in-ear determination is made in step 116. In one embodiment, this high-confidence second-stage determination also participates in the first-stage determination (proximity to the user, proper orientation, and microphone-based determination that the user has stopped operating the wearable audio device). In other words, the device is considered (with low confidence) to be in the proper position for use both when it is in the correct physical location and when the user is not operating the device (which is expected to occur once the user is satisfied that the device is in place). In one embodiment, as part of the high-confidence second-stage determination, an indication of a blocked nozzle is determined by a G sdand are calculated simultaneously. If the blocked nozzle calculation indicates that the nozzle is blocked, the high-confidence decision can be delayed for a short period of time to ensure that the user has stopped manipulating the earphone. If the in-ear condition remains indicated after that time, a high-confidence decision is made. After the second-stage high-confidence decision is made, a second group of earphone functions is enabled in step 118. In some embodiments, the second group of functions are different from the first group of functions. In one embodiment, the second group of functions includes both functions involved in user interaction (such as switches, capacitive touch sensors, and microphone beamforming) and tuning of the active noise reduction system. In some embodiments, multiple stages can be performed on different subsystems. For example, there could be a sensor subsystem (using a proximity sensor, an orientation sensor, and an internal microphone) used in a first, low-confidence stage, and a microphone subsystem (using internal and external microphones) used in a second, high-confidence stage. This would allow the microphone subsystem to be turned on only when needed to conserve power. This design would require some messaging between the subsystems.

[0035] In some embodiments, monitoring of proximity and orientation sensors continues during the process of making the second-stage determination. One reason is to be able to determine whether the wearable audio device has been removed from its use position. For example, an earbud may be placed in the ear and then quickly removed. Or perhaps the user may continue to adjust the earbud for a short period of time after placing it in the ear. By monitoring the proximity and / or orientation sensors throughout the entire startup sequence, there may be greater confidence in determining that the device is in place and that the user has completed operating the device. Also, continuous or periodic monitoring of the microphone and calculation of a transfer function may be used to confirm that the device has been moved from its use position (e.g., removed from the ear). In some embodiments, the processor may enable a timer that may be used as part of the proper location / improper location determination. For example, if the high confidence determination remains for at least a short period of time (perhaps 1-2 seconds), there may be greater confidence that the user has stopped adjusting the device's position. Also, a timer can be used to turn off earbud functionality only after a short time if the proximity sensor stops sensing proximity (which can happen if the earbuds are removed from the ear), which can help prevent erroneous location determinations that could annoy the user. For example, if the driver and external microphone are disabled when the device is removed from its use location, an erroneous determination could cut off a phone call or music or podcast against the user's wishes.

[0036] Figure 4 shows the transfer function (G sd ) is a graph 130 showing the transfer function when the earphone is in the ear, while the dotted line 132 shows the transfer function when the earphone is in free space. As can be seen, the magnitude of the transfer functions differs for frequencies up to 1,000 Hz. Therefore, determining the transfer function in the range 0 to 1,000 Hz indicates whether the earphone is in the ear or not.

[0037] When a process is depicted or suggested by a block diagram, the steps may be performed by one element or by multiple elements. These steps may be performed collectively or at different times. Elements performing activities may be physically located in the same location, in close proximity to each other, or physically separated. One element may perform more activities than one block. Audio signals may be coded or uncoded and may be transmitted in either digital or analog form. Conventional audio signal processing equipment and audio signal computing may be omitted from the drawings.

[0038] The example systems and methods described herein include computer components and computer-implemented steps that will be apparent to those skilled in the art. For example, it should be understood by those skilled in the art that the computer-implemented steps may be stored as computer-executable instructions on a computer-readable medium, such as, for example, a floppy disk, a hard disk, an optical disk, flash ROM, non-volatile ROM, and RAM. Furthermore, it should be understood by those skilled in the art that the computer-executable instructions may be executed on a variety of processors, such as, for example, a microprocessor, a digital signal processor, a gate array, etc. For ease of explanation, not all steps or elements of the above systems and methods are described herein as part of a computer system, but those skilled in the art will recognize that each step or element may have a corresponding computer system or software component. Accordingly, such computer systems and / or software components are enabled by describing their corresponding steps or elements (i.e., their functionality) and are within the scope of the present disclosure.

[0039] Although multiple implementations have been described, it is nevertheless understood that additional modifications can be made without departing from the scope of the inventive concepts described herein, and accordingly, other examples are within the scope of the following claims. [Explanation of symbols]

[0040] 10. Wireless in-ear earphones 12 Body or housing 14 parts 15 Opening 16 Retention Loop 20 Earphones 21 Housing 30 Converter 32 diaphragm 33 Coil 34 Magnetic Structure 35 Front Plate 36 cups 38 Transducer Magnet 40 Transducer Printed Circuit Board (PCB) 41 Pad 42 pads 50 Front housing part 51 Neck 52 Cavity 54 Sound exit 60 Rear housing part 62 Rear housing part 64 Grill 80 Internal Microphone 81 External microphone

Claims

1. A wearable audio device, comprising: an electroacoustic transducer for generating sound; a proximity sensor configured to detect when the wearable audio device is in proximity to a user; an orientation sensor configured to detect an orientation of the wearable audio device; an internal microphone positioned within a housing of the wearable audio device and configured to detect sound within a cavity formed at least in part by a portion of the housing; a processor configured to estimate (i) whether the wearable audio device is in position on the user's body based on the proximity sensor and the orientation sensor, and (ii) whether the user has completed placing the wearable audio device in position on the user's body based on the internal microphone; The wearable audio device, wherein the processor is further configured to initiate a first group of functions of the wearable audio device, including background functions, by inferring (i) that the wearable audio device is in a proper position on the user's body based on the proximity sensor and the orientation sensor, and (ii) that the user has completed placing the wearable audio device in a proper position on the user's body based on the internal microphone.

2. an external microphone configured to sense sound outside the housing; 2. The wearable audio device of claim 1, wherein the processor is further configured to (iii) initiate a second group of functions of the wearable audio device, including user interaction and tuning of an active noise reduction system, by estimating that the wearable audio device is in place on the user's body based on a transfer function between the external microphone and the internal microphone.

3. The wearable audio device of claim 1 , wherein the proximity sensor includes an infrared sensor.

4. The wearable audio device of claim 1 , wherein the orientation sensor includes an inertial measurement unit (IMU).

5. The wearable audio device of claim 4 , wherein the IMU comprises an accelerometer used to detect an orientation of the wearable audio device.

6. 10. The wearable audio device of claim 1, further comprising an external microphone configured to sense sounds outside the housing, and wherein the processor's estimation of whether the wearable audio device is in place on the user's body is further based on a transfer function between the external microphone and the internal microphone.

7. The wearable audio device of claim 6 , wherein the processor is further configured to cause the electro-acoustic transducer to generate a sound on which the transfer function is based.

8. 8. The wearable audio device of claim 7, wherein the transfer function is determined at frequencies up to 1,000 Hz.

9. 8. The wearable audio device of claim 7, wherein the processor is further configured to cause the electro-acoustic transducer to generate sound at two different frequencies, a first frequency being at least 1,500 Hz, the processor configured to determine whether a wearable audio device nozzle is blocked based at least in part on the first frequency, and a second frequency being less than or equal to 1,000 Hz, the processor configured to determine whether the wearable audio device is in place on the user's body based at least in part on the second frequency.

10. The wearable audio device of claim 7 , wherein the generated sound is part of a wearable audio device activation tone sequence.

11. 7. The wearable audio device of claim 6, wherein the processor's estimation of whether the wearable audio device is in place on the user's body includes two successive steps: a first step based on at least the proximity sensor, the orientation sensor, and the internal microphone, and a second step based on at least the internal microphone and the external microphone.

12. 12. The wearable audio device of claim 11, wherein the processor is configured to initiate a first group of wearable audio device functions based on the first step and a second group of wearable audio device functions based on the second step, the functions of the second group being different from the functions of the first group.

13. 13. The wearable audio device of claim 12, wherein the first and second groups of functions include at least one of telephone answering capability, Bluetooth connectivity, beamforming of microphones carried by the wearable audio device, playback of audio received from an external audio source, activation of user interface functions, and tuning of an active noise reduction system.

14. The wearable audio device of claim 11 , wherein during at least the first step, the internal microphone is monitored at a frequency within a range of 0 to 20 Hz.

15. 10. The wearable audio device of claim 1, wherein the proximity sensor has an output, and the processor's estimation of whether the wearable audio device is in place on the user's body is based in part on the level of the output of the proximity sensor.

16. 10. The wearable audio device of claim 1, wherein the processor is configured to enable predetermined wearable audio device functions after the processor estimates whether the wearable audio device is in place on the user's body.

17. 17. The wearable audio device of claim 16, wherein the predetermined wearable audio device functions include at least one of telephone answering capability, Bluetooth connectivity, beamforming of microphones carried by the wearable audio device, playback of audio received from an external audio source, enabling user interface functions, and tuning of an active noise reduction system.

18. 1. A method of detecting when a wearable audio device is in position on a user's body, the wearable audio device comprising: an electro-acoustic transducer for producing sound; a proximity sensor configured to detect when the wearable audio device is in proximity to a user; an orientation sensor configured to detect an orientation of the wearable audio device; an internal microphone positioned within a housing of the wearable audio device and configured to detect sound within a cavity at least partially formed by a portion of the housing; and an external microphone configured to sense sound outside the housing, the method comprising: estimating whether the wearable audio device is in place on the user's body based on the proximity sensor, the orientation sensor, and the internal microphone; estimating whether the user has placed the wearable audio device in position on the user's body based on the internal microphone; initiating a first group of functions of the wearable audio device, including background functions, by estimating that the wearable audio device is in position on the user's body based on the proximity sensor and the orientation sensor, and that the user has completed placing the wearable audio device in position on the user's body based on the internal microphone; A method comprising:

19. 20. The method of claim 18, further comprising initiating a second group of functions of the wearable audio device, including user interaction and tuning of an active noise reduction system, by estimating that the wearable audio device is in place on the user's body based on a transfer function between the external microphone and the internal microphone.

20. 20. The method of claim 18, wherein a processor is configured to cause the electro-acoustic transducer to generate sound after the processor estimates that the wearable audio device is in place on the user's body, and the processor is further configured to calculate a transfer function between the external microphone and the internal microphone over a specified frequency or frequency range of the generated sound.

21. 20. The method of claim 18, wherein the processor's estimation of whether the wearable audio device is in place on the user's body includes two consecutive steps: a first step based on at least the proximity sensor, the orientation sensor, and the internal microphone, and a second step based on at least the internal microphone and the external microphone; and wherein the processor is configured to initiate a first group of wearable audio device functions based on the first step and a second group of wearable audio device functions based on the second step, and the functions of the second group are different from the functions of the first group.

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