Headband headphone with on-ear detection

Abstract

A wireless headband headphone (100) comprises two earcups (120L,120R) connected by a headband (110), with each earcup comprising a transducer (130L,130R) for audio playback, and at least one of the earcups comprising an on-ear detection sensor (140L, 140R), a battery (150) and control circuitry (160L,160R). In order to save power for increasing the headphone operating time and provide advantageous functions to users, the control circuitry (160) is adapted for operating the headphone (100) at least partly depending on signals of the on-ear detection sensors (140), wherein each of the earcups (120L,120R) can be switched separately to an individual earcup operating mode. In embodiments, a doffed earcup can be switched off while a donned earcup can continue normal operation or can be switched to a transparent mode.

Description

[0001] The invention relates to a headphone, in particular a headband headphone, with side specific on-ear detection.Background

[0002] Different types of headphones are commonly used. While one type of headphones that is often referred to as earphones has two separate parts each of which to be fixed in an ear of a user, another type is a single element comprising two earpieces that are connected to each other. In a traditional design, the earpieces are earcups that are fixedly connected by a headband. Both types of headphones are available either with a connection cable or as wireless headphones. Generally, wireless headphones have a power source included, such as a rechargeable battery.

[0003] It is known to equip headphones with on-ear detection (OED) or on-head detection. With this type of detection, it is possible to detect automatically whether or not the user is wearing the headphone: when the headphone is not being worn (or doffed), it can be automatically switched off, and / or when it is being worn (or donned), it can automatically be switched on. Different types of detectors are known, e.g. acoustical, optical, capacitive, pressure detectors etc.

[0004] Further, it is common for some users to wear their headband headphone at least temporarily with just one earcup covering the respective ear, while the other ear remains uncovered, so that the user can hear ambient sound. This wearing style is sometimes referred to as "DJ style".

[0005] The operating time or usage time before recharging is required is an important feature of wireless headphones. Thus, it is generally desirable to save power.Summary of the Invention

[0006] The present invention is based on recognition of the fact that it is advantageous for the user if at least one of the earcups of a headband headphone can be separately and automatically switched into one of a plurality of modes. The term "earcup operating mode" is used herein to indicate that such mode refers to a single earcup. According to the invention, the two earcups of a headband headphone can be operated in different earcup operating modes. In other words, each earcup can be operated in a different earcup operating mode than the other earcup. For this purpose, side-specific on-ear detection is used. In an embodiment, this may be a dual on-ear detection, i.e. separate on-ear detection for each earcup, wherein there is at least one on-ear detector in each of the earcups. Thus, although both earcups are part of a single one-piece headphone, in some embodiments it is possible to detect in each earcup separately whether it is donned or doffed, and in response a corresponding earcup operating mode for the earcup can be selected automatically. In another embodiment, it is possible in at least one of the earcups to detect whether it is donned or doffed, and a corresponding earcup operating mode for this earcup and / or for the other earcup can be selected automatically, wherein the two earcups are switched into different earcup operating modes. This is advantageous in various aspects, including power saving and user comfort.

[0007] In one aspect, a wireless headband headphone comprises two earcups connected by a headband, wherein each earcup comprises a transducer for audio playback and at least one earcup comprises at least one on-ear detection sensor. At least one of the earcups comprises a battery and at least one of the earcups comprises control circuitry, wherein the control circuitry is adapted for operating the headphone at least partly depending on signals of said on-ear detection sensor or sensors. The control circuitry is adapted for switching one or both of the earcups separately into an earcup operating mode such that both earcups are not in the same earcup operating mode. For example, earcup operating modes may be playback mode, sleep mode, silent mode or transparent mode, inter alia.

[0008] Different aspects and advantageous embodiments are provided in the following detailed description and in the claims.Brief Description of the Drawings

[0009] The present invention will be better understood from the following detailed description in conjunction with the accompanying drawings, in which like reference numerals designate like parts. The drawings show in Fig. 1 a schematic block diagram of a headband headphone; Fig. 2 a circuit block diagram; and Fig. 3 a flow-chart. Detailed Description

[0010] Fig. 1 shows a schematic block diagram of a headband headphone, according to one embodiment. The headphone 100 comprises two earcups 120L, 120R, which are mechanically and electrically connected by a headband 110 that comprises at least one cable 115. It is noted here that reference signs when referring to a specific side are marked as L or R for left-hand side or right-hand side, while such mark is omitted when referring to both sides. Each of the earcups 120 comprises a transducer 130 for playing back sound, and each of the earcups 120 comprises an on-ear detection (OED) sensor 140 in this embodiment. The OED sensor may also be referred to as on-head detection sensor. Further in the present embodiment, each of the earcups 120 comprises also a microphone 170, which can be used for communication and / or adaptive noise cancelling (ANC). In other embodiments, the headphone 100 may comprise more than two, only one or no microphone.

[0011] Further, the headphone 100 comprises a battery 150 and control circuitry 160. Since one battery 150 is sufficient for operating the wireless headphone, it is located in only one of the earcups 120. Also the control circuitry 160 may be located in only one of the earcups (usually in the other earcup). In the present example, the earcup 120L that comprises the battery 150 comprises control circuitry 160L that is reduced and thus lighter and less complex as compared to control circuitry 160R of the other earcup 120R. Control circuitry 160L, battery 150, transducer 130L, OED sensor 140L and microphone 170L of the left-hand earcup 120L can be connected to the control circuitry 160R of the right-hand earcup 120R via cables 115. For example, signals can be exchanged via cables 115 using a serial bus protocol.

[0012] In the present embodiment, each of the two OED sensors 140L, 140R senses if the respective earcup 120L, 120R is put on-ear (donned) or not put on-ear (doffed), and provides an OED signal indicating that the respective earcup 120L, 120R is donned or doffed to control circuitry 160R. If the OED signals indicate that both earcups 120 are donned, the headphone may operate conventionally, e.g. performing audio playback via the transducers 130 in both earcups. Thus, in this case both earcups can be in the same earcup operating mode, as is conventional.

[0013] If the OED signals indicate that one earcup is donned and the other earcup is doffed, control circuitry 160R switches the doffed earcup into a different earcup operating mode than the donned earcup; for example, it switches at least audio playback off for the doffed earcup only. For example, if OED sensor 140R senses that the right-hand earcup 120R is doffed, audio playback by the transducer 130R of this earcup is switched off; this may include the playback of the caller's voice if a phone call is being made. Also other functions of this earcup may be switched off, in particular those that consume a relatively high amount of power, such as the audio amplifier and / or adaptive noise cancellation (ANC). Thus, this earcup may be switched into a power saving mode, power-down mode or silent mode, for example. If the other OED sensor 140L senses that (in this example) the left-hand earcup 120L is not doffed (i.e., it is donned), the left-hand earcup 120L is not switched off and may continue working, for example in a playback mode, telephone mode or transparent mode.

[0014] If the OED sensors 140 indicate that both earcups 120 are doffed for at least a predefined time, which may be in the range of e.g. 1 to 10 seconds or longer, both earcups of the headphone can be switched off or switched into a sleep mode. If they are switched into sleep mode and the OED sensors 140 indicate that both earcups 120 are still doffed after a predefined time, which may be in the range of e.g. 10 to 120 seconds, the headphone can be switched off completely. In one embodiment, the control circuitry 160R is only switched off if the headphone 100 is switched off completely, but not if only one of the earcups is switched off.

[0015] If the OED sensors 140 sense that one earcup is donned while the other earcup is doffed ("DJ style"), various options are available for the donned earcup. In one embodiment, the donned earcup continues operating in its current earcup operating mode, such as audio playback for music or a phone call. In another embodiment, the donned earcup continues operating in its current earcup operating mode with reduced playback volume and / or microphone sensitivity. If for example one OED sensor 140L senses that left-hand earcup 120L is doffed while the other OED sensor 140R senses that right-hand earcup 120R is donned, playback volume for the right-hand earcup 120R may be reduced. This mode has the advantage that it will be easier for the user to listen to his or her ambience, which will usually be the reason for doffing a single earcup. Optionally, a similar mode may be additionally used in which the microphone in the donned earcup is switched off or its microphone sensitivity is reduced; this may be advantageous in making it more difficult for a conversation partner in a phone call to listen to ambient talkers. In yet another embodiment, the donned earcup suspends its current earcup operating mode and switches to a transparent mode or ambient mode, using its microphone. This enables the user to listen to his or her ambience with both ears, which is advantageous for better understanding and allows spatial hearing. In this case, in one embodiment an ongoing phone call may be put on hold and / or music playback may be paused. In a similar embodiment, the ambient signal may be mixed with sound of a phone call or music being played back in the donned earcup. Optionally, the microphone sensitivity in the donned earcup may be reduced also in this mode.

[0016] In all these embodiments, the previously used mode can be resumed automatically after both earcups are donned again. For this purpose, control circuitry 160 may store a value indicating which mode (i.e., which two earcup operating modes) was previously used, so that the headphone may return to this mode after both earcups are donned again.

[0017] One advantage is that a substantial amount of power can be saved if playback in the doffed earcup is switched off while a headband headphone is being worn in "DJ style". Exemplary measurements resulted in power savings in the range of 10% and beyond.

[0018] Fig. 2 shows a block diagram of electronic circuitry 200, which constitutes at least a portion of control circuitry 160. Circuitry 200 comprises a communication module 260, such as a wireless interface, which may in particular be a Bluetooth receiver. It receives digital audio data wirelessly and provides the audio data to a router block 210, which extracts digital audio data for the different audio channels to be played back by the transducers. Router block 210 may additionally perform other functions, as described below. The digital audio data are converted 220 from digital to analog data, which are then amplified 230 and provided to the transducers for output. A control block 240, which in this embodiment communicates via an interface block 250 with at least two OED sensors located in the two earcups (not shown in Fig. 2), may control at least each of the amplifiers 230 separately to suspend their power consumption, e.g. by switching them off. In another embodiment, control block 240 communicates via interface block 250 with at least one OED sensor located in one of the two earcups (not shown in Fig. 2) and may control at least the amplifiers 230 separately to suspend power consumption. As described above, control block 240 may switch off e.g. left channel amplifier 230L if it receives via interface 250 signals indicating that the left-hand earcup 120L is doffed while right-hand earcup 120R is donned. Similarly and independently thereof, control block 240 may switch off right channel amplifier 230R if it receives via interface 250 signals indicating that the right-hand earcup 120R is doffed while left-hand earcup 120L is donned.

[0019] In a similar embodiment, control block 240 may switch off not only the channel amplifiers 230, but also other modules, such as the corresponding digital-to-analog converters 220. Further, in embodiments with microphones included in the headphone, control block 240 may also switch off pre-amplifiers 270 and / or analog-to-digital converters 280 for the microphones in the doffed earcup, and / or ANC circuitry 290 if present. This is particularly effective, since ANC requires a relatively high amount of power and each of the earcups 120L,120R may comprise at least two microphones, including an ANC feed-forward microphone and an ANC feedback microphone. Their corresponding input signals Mic L,FF , Mic L,FB , Mic R,FF , Mic R,FB are separately amplified 270 and converted 280 from analog to digital signals. Exemplarily, amplifiers 270 may be PGAs (pre-gain amplifiers or programmable gain amplifiers). Thus, switching ANC off for a doffed earcup in this example saves power that would otherwise be required for two pre-amplifiers 270, two ADCs 280 and one ANC processing block 290. In one embodiment, ANC is switched off only for the doffed earcup and remains switched on for the donned earcup. However, it may also be advantageous to suspend ANC for the donned earcup if the other earcup is doffed. Thus, in one embodiment, the headphone may provide a mode that disables ANC completely if at least one earcup is doffed, e.g. for optimizing the headphone for a long operating time.

[0020] In at least one operating mode, a donned earcup is automatically switched to an at least partially transparent or hear-through mode if the other earcup is doffed. This means that the user may hear ambient sound, which may be either mixed with playback sound in one earcup operating mode or reproduced without playback sound in another earcup operating mode. In the hear-through mode, input signals from one or more of the donned-side microphones (preferably the ANC feed-forward microphone) may be routed through the respective pre-amp 270 and ADC 280 to be added directly to the output signal Out L ,Out R to be reproduced by the respective transducer 130. In this case, at least the processing in the respective one or in both the ANC blocks 290 may be omitted, which saves power. Signals from ANC feedback microphones may then generally be disregarded in this mode, which saves power at least for their respective pre-amp 270 and ADC 280.

[0021] In one embodiment, the user may select among at least the above-described modes with respect to ANC in the donned earcup, using a software interface and e.g. a smartphone.

[0022] In the above examples, it is assumed for simplicity that router block 210 combines (e.g. adds) noise cancelling signals received from ANC blocks 290 with playback signals received from the communication module 260. However, such combination may also be performed in another block.

[0023] Fig. 3 shows a flow-chart of an automatically executed method for operating a headband headphone, in one embodiment. The method 300 determines in an initial optional step 310 if both earcups are donned. This may be done after switching on the headphone via a separate switch or while the headphone is in any kind of sleep mode. If both earcups are donned, both earcups are powered on 320 in order to work in normal earcup operating mode each, e.g. in audio playback mode. Signals of the OED sensors 140 are only evaluated when the sensors detect an event, such as a user donning or doffing an earcup. As long as both earcups are donned, normal operation proceeds 331; in the normal operation mode 331, both earcups are in the same earcup operating mode. Once the wearing status of at least one earcup changes, the respective OED sensor 140 detects an event and provides a signal, e.g. an interrupt signal to the control circuitry 160. In response, control logic decides 330 on a separate earcup operating mode for each earcup, as follows.

[0024] In the following, it is to be noted that headphone operating modes, such as e.g. "right-handed mode" or "left-handed mode", refer to the complete headphone and are generally to be distinguished from earcup operating modes, which refer to a single earcup.

[0025] If the left-hand earcup is donned and the right-hand earcup is doffed (which is called "right-handed mode" herein since the user probably uses his or her right hand for doffing the earcup) 332, the left-hand earcup may continue operation in its current earcup operating mode, in one embodiment, while the right-hand earcup is switched into an earcup operating mode where playback (and / or a phone call, as described above) is suspended. ANC and / or microphone circuitry in the two earcups may be operated as described above, e.g. ANC is switched off completely and microphone related circuitry is switched off for the doffed right-hand earcup and switched on for the donned left-hand earcup.

[0026] If the right-hand earcup is donned and the left-hand earcup is doffed ("left-handed mode") 333, the right-hand earcup may continue operation in its current earcup operating mode, in one embodiment, while the left-hand earcup is switched into an earcup operating mode where playback (and / or a phone call, as described above) is suspended. Again, ANC and / or microphone related circuitry for the two earcups may be operated as described above.

[0027] In both cases, the donned earcup may also switch to a transparent or semi-transparent earcup operating mode instead of remaining in its current earcup operating mode, as described above.

[0028] If the sensors 140 (i.e. their OED signals) indicate that both earcups are doffed, playback (and / or ANC and / or microphone related circuitry) for both sides will be switched off 334. At least the sensors 140 may continue to operate, however. In this embodiment, the control logic 240 may use a timer to wait 340 for a defined time, e.g. 1 minute, before deciding 350. If after this time the sensors 140 indicate that at least one of the earcups is donned ("N" branch of decision 350), operation may continue with decision step 330. Alternatively, in another embodiment the operation may continue with power being switched on for both earcups in step 320, regardless of which earcup is donned. If after the defined time the sensors 140 still indicate 350 that both earcups are doffed ("Y" branch of decision 350), the headphone may be switched into a sleep mode 360, i.e. both earcups are switched into a power saving earcup operating mode. It may return to normal operation mode if both earcups are donned 310 and / or the user switches the headphone on manually.

[0029] In some embodiments, either of the "right-handed mode" 332 and "left-handed mode" 333 is implemented, but not both; in this case, it may be sufficient to have only one OED sensor 140 in one of the earcups. For example, if the "right-handed mode" 332 is implemented and "left-handed mode" 333 is not implemented, the OED sensor 140L in the left-hand earcup can be omitted. If right-hand OED sensor 140R signals DOff R , the right-hand earcup can be switched off while the left-hand earcup continues operation or switches to a transparent mode or hear-through mode, as described above. In some embodiments, the left-hand earcup continues its operation in this case without time limit, which can be called "right-handed DJ mode"; in other embodiments, the left-hand earcup in this case continues its operation for a specified time, e.g. 30 seconds or few minutes. If after the specified time the OED sensor 140R still signals DOff R , also the left-hand earcup may be switched off (as in mode 334), otherwise the device may switch back to normal mode 331. In some embodiments, the user may configure the headphones by setting the specified time via a control software, e.g. by selecting between 30 seconds, 1 or 2 minutes and "unlimited" ("DJ mode" herein, i.e. the earcup without OED sensor will not be switched off), and / or by selecting whether the earcup that does not have an OED sensor performs audio playback or ambience hear-through or any mixture of both in the "right-handed mode" 332 or "left-handed mode" 333.

[0030] In one embodiment, the "right-handed mode" 332, "left-handed mode" 333 and DJ mode can be entered only from a normal operating mode 320,331, in which both earcups operate normally.

[0031] In one embodiment, the invention relates to a computer-readable data carrier having stored thereon instructions that when executed cause a processor in a headphone to perform the above-described method.

[0032] Different types of sensors or detectors can be used, such as e.g. acoustical, optical, capacitive or radar sensors, pressure detectors etc.

[0033] It is noted that in this description the terms "left-hand earcup" or "right-hand earcup" each refer to one of the earcups, which is intended to be worn on the respective ear of the user. This is independent from the fact that some users might wear their headphone backwards.

[0034] It is clear that various embodiments mentioned in the description above may be combined if applicable, even if such combination is not expressly mentioned.

Claims

1. A wireless headband headphone (100) comprising - two earcups (120L, 120R) connected by a headband (110), each earcup comprising a transducer (130L, 130R) for audio playback, wherein at least one of the earcups comprises an on-ear detection sensor (140L, 140R); - at least one of the earcups comprising a battery (150) and at least one of the earcups comprising control circuitry (160), wherein the control circuitry (160) is adapted for operating the headphone (100) partly depending on signals of said at least one on-ear detection sensor (140L, 140R); - wherein the control circuitry (160) is adapted for switching an earcup operating mode in at least one of the earcups separately from an earcup operating mode in the other earcup.

2. The wireless headband headphone according to claim 1, wherein the at least one on-ear detection sensor (140L, 140R) provides an on-ear detection signal indicating that the respective earcup is donned or doffed, and wherein the control circuitry (160) is adapted for switching off audio playback for only the respective doffed earcup if said on-ear detection signal indicates that the respective earcup is doffed.

3. The wireless headband headphone according to claim 2, wherein the control circuitry (160) is adapted for controlling the audio playback to remain switched on for the other earcup.

4. The wireless headband headphone according to claim 2, wherein the control circuitry (160) is adapted for switching off the audio playback for the other earcup, and for switching said other earcup to a transparent mode.

5. The wireless headband headphone according to claim 2, wherein the control circuitry (160) is adapted for controlling the audio playback to remain switched on for the other earcup and for reducing the volume of the audio playback, and for switching said other earcup to a transparent mode, wherein an ambient sound signal and played back audio are mixed.

6. The wireless headband headphone according to one of the claims 1 to 5, wherein each of the earcups comprises at least one on-ear detection sensor (140L, 140R) for providing an on-ear detection (OED) signal indicating that the respective earcup is donned or doffed, and wherein the control circuitry (160) is adapted for switching audio playback off for the doffed earcup if said OED signals indicate that one earcup is donned and the other earcup is doffed.

7. The wireless headband headphone according to claim 6, wherein the control circuitry (160) is adapted for switching off the headphone, or for switching the headphone into a sleep mode, if both sensors (140L, 140R) indicate that both earcups (120L, 120R) are doffed for a certain time.

8. The wireless headband headphone according to claim 6 or 7, wherein the battery (150) and control circuitry (160) are comprised in one of the earcups (120R) only, and the headband (110) comprises at least one cable (115) for providing signals to the other earcup's transducer and for receiving signals at least from the other earcup's sensor (140L).

9. The wireless headband headphone according to claim 8, wherein the headband comprises at least one cable (115) for receiving signals from a microphone located in the other earcup, the at least one cable (115) in the headband being used for communication using a serial bus protocol.

10. The wireless headband headphone according to one of the claims 1 to 9, wherein the control circuitry (160) is adapted for initially disabling the on-ear detection sensor or sensors or the switching, and for enabling the sensor or sensors or the switching after a predefined minimum time.

11. A method (300) for operating a headband headphone comprising a first earcup and a second earcup, the method comprising - automatically detecting (330) that the first earcup is doffed while the first and the second earcup both operate in a first earcup operating mode (331); and - upon said detecting, switching the doffed first earcup to a different second earcup operating mode (332, 333), wherein after said switching the first and second earcups operate in different earcup operating modes.

12. The method according to claim 11, wherein the donned earcup is switched to a transparent mode upon said detecting.

13. The method according to claim 11 or 12, wherein the method is initiated by detecting (310) that both earcups are donned for a predefined minimum time.

14. A computer-readable data carrier having stored thereon instructions that when executed cause the computer to perform a method of one of the claims 11 to 13.

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