HEARING AID COMPRISING AN ACTIVE OCCLUSION CANCELLATION SYSTEM

Abstract

Disclosed herein are embodiments of a hearing aid configured to be worn by a user at or in an ear of the user and having an ITE-part adapted for being located at or in an ear canal of the user. The hearing aid can include an active occlusion cancellation system (AOCS) for providing an acoustic anti-occlusion signal configured to cancel or diminish a sense of occlusion of the user when the user is speaking, or otherwise is using his or her voice, or when otherwise moving the jaws. Methods of operating a hearing aid are further disclosed.

Claims

1. A hearing aid configured to be worn by a user at or in an ear of the user, the hearing aid comprising: an ITE-part adapted for being located at or in an ear canal of the user; at least one first input transducer configured to provide corresponding at least one first electric input signal representing sound; a hearing aid processor configured to provide a processed signal in dependence of said at least one electric input signal; a first output transducer configured to play sound to the user in dependence of said processed signal, or a signal dependent thereon; an active occlusion cancellation system for providing an acoustic anti-occlusion signal configured to cancel or diminish a sense of occlusion of the user when the user is speaking, or otherwise is using his or her voice, or when otherwise moving the jaws; wherein the active occlusion cancellation system comprises: an ear canal input transducer located in said ITE-part and configured to provide an electric ear canal input signal representing sound in said ear canal, when the user wears the hearing aid; an ear canal sound estimation unit configured to estimate sound in said ear canal and to provide an electric anti-occlusion signal in dependence of said electric ear canal input signal and said processed signal; a second output transducer located in said ITE-part configured to play sound to the user and to provide said acoustic anti-occlusion signal in dependence of said electric anti-occlusion signal, wherein said second output transducer is specifically adapted to provide sound at frequencies below a threshold frequency.

2. A hearing aid according to claim 1 comprising a BTE-part adapted for being located at or behind the ear of the user and a connecting element adapted for mechanically and electrically connecting said BTE-part and said ITE-part.

3. A hearing aid according to claim 2 wherein said first output transducer is located in said BTE-part.

4. A hearing aid according to claim 1 wherein said at least one first input transducer comprises a microphone.

5. A hearing aid according to claim 1 wherein said at least one first input transducer comprises an audio receiver.

6. A hearing aid according to claim 1 wherein said first or second output transducer comprises a loudspeaker.

7. A hearing aid according to claim 1 wherein said second output transducer is specifically adapted to provide sound at frequencies below a threshold frequency smaller than or equal to 1 kHz.

8. A hearing aid according to claim 1 configured to provide that the first and second output transducers play sound in different frequency ranges.

9. A hearing aid according to claim 8, configured to provide that the first output transducer plays sound above a first threshold frequency (f.sub.th,1), and that the second output transducer plays sound below a second threshold frequency (f.sub.th,2), wherein the first threshold frequency (f.sub.th,1) is smaller than or equal to the second threshold frequency (f.sub.th,2).

10. A hearing aid according to claim 1 wherein said connecting element comprises an acoustic tube.

11. A hearing aid according to claim 1 comprising an own voice detector configured to estimate whether or not, or with what probability, a given input sound originates from the voice of the user and to provide an own voice control signal in dependence thereof.

12. A hearing aid according to claim 1 comprising a movement detector configured to detect said movement of the jaws of the user, and to provide a jaw movement control signal in dependence thereof.

13. A hearing aid according to claim 11 wherein the ear canal sound estimation unit (ECSE) is configured to provide said electric anti-occlusion signal in dependence of said own voice control signal and/or said jaw movement control signal.

14. A hearing aid according to claim 11 configured to operate in different modes, including an anti-occlusion-mode wherein the active occlusion cancellation system is enabled, and where the anti-occlusion-mode is enabled or disabled in dependence of said own voice control signal and/or said jaw movement control signal.

15. A hearing aid according to claim 14 wherein the change of enabling and disabling the anti-occlusion cancellation system may be associated with a fading scheme providing a gradual change over time from one mode of operation to another.

16. A hearing aid according to claim 1 wherein the first output transducer is a tweeter and the second output transducer is a woofer.

17. A binaural hearing aid system comprising first and second hearing aids according to claim 1, wherein the first and second hearing aids are configured to establish a communication link between them allowing a coordination of enabling and disabling the anti-occlusion cancellation system.

18. A method of operating a hearing aid configured to be worn by a user at or in an ear of the user, the hearing aid comprising: an ITE-part adapted for being located at or in an ear canal of the user; at least one first input transducer configured to provide corresponding at least one first electric input signal representing sound; a hearing aid processor configured to provide a processed signal in dependence of said at least one electric input signal; a first output transducer configured to play sound to the user in dependence of said processed signal, or a signal dependent thereon; an ear canal input transducer located in said ITE-part and configured to provide an electric ear canal input signal representing sound in said ear canal, when the user wears the hearing aid; a second output transducer located in said ITE-part configured to play sound to the user; the method comprising: providing an acoustic anti-occlusion signal configured to cancel or diminish a sense of occlusion of the user when the user is speaking, or otherwise is using his or her voice, or when otherwise moving the jaws; estimating sound in said ear canal and to provide an electric anti-occlusion signal in dependence of said electric ear canal input signal and said processed signal; and, providing via said second output transducer an acoustic anti-occlusion signal to the user's ear canal in dependence of said electric anti-occlusion signal, wherein said second output transducer is specifically adapted to provide sound at frequencies below a threshold frequency.

19. A hearing aid configured to be worn by a user at or in an ear of the user, the hearing aid comprising: an ITE-part adapted for being located at or in an ear canal of the user; a BTE-part adapted for being located at or behind the ear of the user; and a connecting element adapted for mechanically and electrically connecting said BTE-part and said ITE-part at least one first input transducer configured to provide corresponding at least one first electric input signal representing sound; a hearing aid processor configured to provide a processed signal in dependence of said at least one electric input signal; a first output transducer located in said BTE-part configured to play sound to the user in dependence of said processed signal, or a signal dependent thereon, said first output transducer being specifically adapted to frequencies above a threshold frequency; an active occlusion cancellation system for providing an acoustic anti-occlusion signal configured to cancel or diminish a sense of occlusion of the user when the user is speaking, or otherwise is using his or her voice, or when otherwise moving the jaws; wherein the active occlusion cancellation system comprises an ear canal input transducer located in said ITE-part and configured to provide an electric ear canal input signal representing sound in said ear canal, when the user wears the hearing aid; an ear canal sound estimation unit configured to estimate sound in said ear canal and to provide an electric anti-occlusion signal in dependence of said electric ear canal input signal and said processed signal; a second output transducer located in said ITE-part configured to play sound to the user and to provide said acoustic anti-occlusion signal in dependence of said electric anti-occlusion signal, wherein said second output transducer is specifically adapted to provide sound at frequencies below said threshold frequency.

20. A hearing aid according to claim 19 wherein said threshold frequency is in the range between 400 Hz and 800 Hz.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0103] The aspects of the disclosure may be best understood from the following detailed description taken in conjunction with the accompanying figures. The figures are schematic and simplified for clarity, and they just show details to improve the understanding of the claims, while other details are left out. Throughout, the same reference numerals are used for identical or corresponding parts. The individual features of each aspect may each be combined with any or all features of the other aspects. These and other aspects, features and/or technical effect will be apparent from and elucidated with reference to the illustrations described hereinafter in which:

[0104] FIG. 1 shows an embodiment of a hearing aid according to the present disclosure,

[0105] FIG. 2A shows an embodiment of a BTE-style hearing aid comprising an occlusion cancellation system according to the present disclosure; and

[0106] FIG. 2B shows an embodiment of an ITE-style hearing aid comprising an occlusion cancellation system according to the present disclosure,

[0107] FIG. 3 shows a simplified block diagram of an embodiment of a hearing aid comprising a first embodiment of an active anti-occlusion cancellation system according to the present disclosure,

[0108] FIG. 4 shows a simplified block diagram of an embodiment of a hearing aid comprising a second embodiment of an active anti-occlusion cancellation system according to the present disclosure, and

[0109] FIG. 5A shows a conventional anti-occlusion system;

[0110] FIG. 5B shows a first embodiment of an anti-occlusion system with two loudspeakers according to the present disclosure; and

[0111] FIG. 5C shows a second embodiment of an anti-occlusion system with two loudspeakers according to the present disclosure.

[0112] The figures are schematic and simplified for clarity, and they just show details which are essential to the understanding of the disclosure, while other details are left out. Throughout, the same reference signs are used for identical or corresponding parts.

[0113] Further scope of applicability of the present disclosure will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the disclosure, are given by way of illustration only. Other embodiments may become apparent to those skilled in the art from the following detailed description.

DETAILED DESCRIPTION OF EMBODIMENTS

[0114] The detailed description set forth below in connection with the appended drawings is intended as a description of various configurations. The detailed description includes specific details for the purpose of providing a thorough understanding of various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. Several aspects of the apparatus and methods are described by various blocks, functional units, modules, components, circuits, steps, processes, algorithms, etc. (collectively referred to as elements). Depending upon particular application, design constraints or other reasons, these elements may be implemented using electronic hardware, computer program, or any combination thereof.

[0115] The electronic hardware may include micro-electronic-mechanical systems (MEMS), integrated circuits (e.g. application specific), microprocessors, microcontrollers, digital signal processors (DSPs), field programmable gate arrays (FPGAs), programmable logic devices (PLDs), gated logic, discrete hardware circuits, printed circuit boards (PCB) (e.g. flexible PCBs), and other suitable hardware configured to perform the various functionality described throughout this disclosure, e.g. sensors, e.g. for sensing and/or registering physical properties of the environment, the device, the user, etc. Computer program shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

[0116] The present application relates to the field of hearing devices, e.g. hearing aids. The present disclosure relates specifically to anti-occlusion in hearing devices, e.g. hearing aids, e.g. in hearing aids comprising a separate, dedicate anti-occlusion, loudspeaker located in an ear canal of a user, e.g. in combination with a BTE-part configured to be located at or behind an ear (pinna) of the user of the hearing aid. The hearing aid may e.g. comprise or be constituted by an ITE-part configured to be located fully or partially in an ear canal of the user. The ITE-part may e.g. comprise an (e.g. customized) ear mould. The standard hearing aid loudspeaker may be located in a BTE-part or in an ITE-part.

[0117] FIG. 1 shows an embodiment of a hearing aid according to the present disclosure. The hearing aid (HD) comprises a BTE-part (BTE) configured to be located at or behind an ear (pinna) of the user of the hearing aid and an ITE-part (ITE) configured to be located fully or partially in an ear canal of the user. The BTE-part and the ITE-part are connected by a connecting element (IC) adapted for mechanically and/or electrically connecting the BTE-part and the ITE-part. The BTE-part (BTE) comprises a housing wherein components of the hearing aid (e.g. electronic components) are enclosed, including a standard loudspeaker for presenting a sound signal representative of sound picked up by microphones of the hearing aid to the user. The connecting element (IC) comprises a sound tube (e.g. having a diameter of 0.9 mm to 1.3 mm) for propagating sound from the standard loudspeaker of the BTE-part to the ITE-part and thus to the user's eardrum, when the hearing aid is worn in or at an ear of the user. The ITE-part (ITE) comprises speaker unit comprising an (anti-occlusion) loudspeaker specifically adapted to counteract (predominantly low-frequency) sounds originating from the user (e.g. the user's voice or chewing movements, etc.) occluded in the ear canal. The hearing aid, e.g. the BTE-part and/or the ITE-part comprise(s) at least one (outward facing) microphone configured to pick up sound from the environment of the hearing aid, and to provide at least one electric input signal representative thereof. The ITE-part comprise(s) at least one (inward facing) microphone configured to pick up sound in the ear canal (e.g. from the residual volume between the ITE-part and the eardrum, when the hearing aid is mounted on the user as intended), and to provide at least one electric input signal representative thereof. The electric input signal from the inward facing microphone is used to estimate an anti-occlusion signal to be played by the anti-occlusion loudspeaker.

[0118] It is proposed to use a separate loudspeaker for generating the (acoustic) anti-occlusion signala loudspeaker which may be optimized for low frequency efficiency (e.g. between 50 Hz and 1 kHz). This loudspeaker is preferably located at the end of the hearing device closest to the eardrum such as in an ear mould or speaker unit attached to a BTE-part of the hearing aid (such type of hearing aid sometimes being termed a RITE style hearing aid). The ear mould may alternatively constitute a standalone hearing aid. The loudspeaker is electrically connectedthrough a digital or analogue processing systemto an inward facing microphone measuring the occlusion signal in front of the eardrum. By using this approach, a dedicated fast acting signal processing system may be provided for solving or decreasing the occlusion problem.

[0119] The normal loudspeaker, typically providing an amplified and noise reduced version of signals picked up by microphones (and/or received by a wireless audio receiver) of the hearing device, may e.g. be located in a BTE-part of the hearing aid (as is common for some hearing aid styles) and connected to an ear mould or speaker unit by an acoustic tube.

[0120] The audiological signal path carrying external speech sounds and other external sounds to the hearing aid user is based on at least one microphone located further away from the eardrum such as in the body of a RITE or BTE hearing aid located behind the ear. The signal(s) from this or these microphones is(are) passed through a prior art hearing aid signal processing system (forward path) and passed on to a standard loudspeaker located outside the ear such as behind the ear, e.g. in the body (BTE-part) of a BTE instrument. The acoustic signal may be transmitted to the ear through a state-of-the-art acoustic tube (e.g. having a diameter in the range from 0.9 to 1.3 mm).

[0121] The proposal allows for a low frequency loudspeaker (e.g. a LF speaker unit) providing optimum performance in relation to the active occlusion cancellation system and for a discreet solution where the in-ear part is physically smaller than if the (standard) high frequency loudspeaker had also been placed in the ear. The location of the anti-occlusion loudspeaker (LF speaker unit) close to the eardrum is advantageous since it enables delivering the signal directly into the cavity in front of the eardrum without any phase distortions due to resonances in the acoustic tubing and with a short delay in this part of the acoustic system. Short delay and accurate phase are important performance parameters of the system in combination with vent size and maximum low frequency output from the (LF) loudspeaker.

[0122] Additionally, the inward facing microphone can also be used for optimizing the signal of the audiological signal path; The output sound level is monitored, and own voice detection can be introduced. The microphone can also capture own voice for communication purposes (phone calls etc.)

[0123] FIG. 2A shows an embodiment of a BTE-style hearing aid (HD) comprising an active occlusion cancellation system according to the present disclosure. The hearing device (HD) comprises a BTE-part (BTE) comprising a loudspeaker (HA-SPK) and an ITE-part (ITE) comprising an (possibly customized) earpiece, e.g. an ear mould (MO). The BTE-part and the ITE-part are connected by an acoustic propagation element (e.g. a hollow tube, IC). The BTE-part (BTE) is adapted for being located at or behind an ear of a user, and the ITE-part (ITE) is adapted for being located in or at an ear canal of a user's ear. The ITE-part comprises a through-going opening providing a loudspeaker sound outlet (SO) for the loudspeaker of the BTE-part (HA-SPK) allowing sound to be propagated via the connecting element (IC) to the ear drum (Eardrum) of the user (cf. sound field S.sub.HA from the hearing aid loudspeaker (HA-SPK) contributing to sound field S.sub.ED at the eardrum). The BTE-part and the ITE-part may (additionally, or alternatively) be electrically connected by electric wires located in or on the connecting element (IC), e.g. in addition to the acoustic propagation channel. The loudspeaker (HA-SPK) of the BTE-part is configured to play into the connecting element (IC) and further into the loudspeaker sound outlet (SO) of the ITE-part (providing sound field S.sub.HA). The loudspeaker is connected by internal wiring in the BTE-part (cf. e.g. schematically illustrated as wiring Wx in the BTE-part) to relevant electronic circuitry of the hearing device, e.g. to a digital signal processor (DSP). The BTE-parts comprises first and second input transducers, e.g. microphones (M.sub.BTE1 and M.sub.BTE2), respectively, which are used to pick up sounds from the environment of a user wearing the hearing aid (cf. sound field S.sub.BTE). The ITE-part comprises an ear-mould (MO) and is intended to allow a relatively large sound pressure level (S.sub.HA) to be delivered to the ear drum of the user (e.g. to a user having a severe-to-profound hearing loss). A part of the sound (S.sub.HA) provided by the loudspeaker (HA-SPK) of the BTE-part may leak out along the interface between the ITE-part and the ear canal tissue. Such leaked sound may lead to unwanted feedback problems if picked by microphones of the hearing aid and amplified and presented to the user via the loudspeaker (HA-SPK). Such acoustic feedback may be controlled by a proper feedback control system (e.g. (partly) compensated by an active noise cancellation system (ANC)).

[0124] The hearing aid further comprises an active occlusion cancellation system configured to cancel or diminish a sense of occlusion of the user when the user is speaking (or otherwise using his or her voice, or by otherwise moving the jaws, e.g. by chewing). This may e.g. be achieved by generating an acoustic anti-occlusion signal in the ear canal (more specifically in the residual volume between the ITE-part and the ear drum, when the ITE-part of the hearing aid is mounted in the user's ear canal). The active occlusion cancellation system is configured to generate the acoustic anti-occlusion signal so that it cancels or diminishes the acoustic signal in the residual volume originating from the user's own voice (etc.), e.g. from such sound propagated from the user's mouths to the residual volume via bone and flesh of the user's face.

[0125] The active occlusion cancellation system (see AOCS in FIG. 3) comprises a (second) (ear canal) input transducer (e.g. an ear canal microphone MEC, e.g. having a microphone inlet (EC-MIL) in a direction of the eardrum, as indicated in FIG. 2A) located in the ITE-part and configured to provide a (second) electric input signal representing sound (S.sub.OC) in said ear canal, when the user wears the hearing aid. The active occlusion cancellation system further comprises an ear canal sound estimation unit configured to estimate sound in the ear canal in dependence of the (second) electric input signal (e.g. from the ear canal microphone MEC) and providing an electric ear canal signal representative of at least a part of the sound in the ear canal. As illustrated in FIG. 3, the ear canal sound estimation unit (ECSE) (included in the digital signal processor (DSP)) is configured to estimate sound (e.g. the sound pressure level) in the ear canal originating from the user's voice and to provide an electric anti-occlusion signal (x.sub.AOC). The active occlusion cancellation system (AOCS) further comprises a (second) separate output transducer (EC-SPK, e.g. a loudspeaker) located in the ITE-part (and e.g. having a sound outlet in a direction of the eardrum, as indicated in FIG. 2A) and configured to play sound (S.sub.AOC) to the user in dependence of the electric ear canal signal provided by the ear canal sound estimation unit. The ear canal sound estimation unit is configured to provide the electric ear canal signal to cancel or attenuate at least a part of the sound in the ear canal when played by the (second) separate output transducer. The sound at the eardrum S.sub.ED is the sum of the contributions S.sub.HA from the hearing aid loudspeaker (HA-SPK) propagated to the residual volume via the (inter)connecting element (IC) and the loudspeaker outlet (HA-SOL) of the ITE-part, the occluded sound (S.sub.OC) originating from the user, and the anti-occlusion sound (S.sub.AOC) delivered by the separate loudspeaker (EC-SPK) (via loudspeaker outlet EC-SOL) located in the ITE-part (these sound contributions being modified by respective acoustic transfer functions from their point of arrival in the ear canal to the eardrum). A further contribution from directly propagated sound through a possible ventilation channel and/or other leakage paths from the environment to the residual volume at the eardrum may exist (the size of such contribution being dependent on the size of the leakage paths). Such further contribution may be handled by an active noise cancellation (ANC) system, cf. e.g. U.S. Pat. No. 8,229,127. Ideally, the anti-occlusion sound (S.sub.AOC) cancels the occluded sound (S.sub.OC) originating from the user's voice, jaw movements, etc. Thereby (ideally) only the desired sound (S.sub.HA) provided by the hearing aid loudspeaker (HA-SPK) and originating from the environment (and/or from streamed sound received by the hearing aid) is the only sound perceivable by the user.

[0126] The separate output transducer (EC-SPK) is in the embodiment of FIG. 2A shown to have its own loudspeaker outlet. The outlet may however be coupled to the loudspeaker outlet (SO) of the loudspeaker (HA-SPK) of the BTE-part (providing the output sound of the forward path of the hearing aid). Thereby, one combined acoustic outlet may be provided.

[0127] The separate (second) output transducer (EC-SPK) (located in the ITE-part) may comprise a dedicated woofer configured to provide a large low frequency output and a small phase shift (e.g. below 500 Hz). The first output transducer (HA-SPK) (located in the BTE-part) may comprise a dedicated tweeter configured to serve mid/high frequencies (e.g. between 500 Hz and 8-10 kHz) required for hearing loss compensation.

[0128] The ITE-part comprises the ear canal input transducer (e.g. a microphone, MEC). The ear canal input transducer (MEC) faces the eardrum (and/or has a microphone inlet facing towards the eardrum) located so that it picks up sound in the ear canal (e.g. from the loudspeaker sound outlet (SO) of the ITE-part and own voice sound propagated through the skull bone and flesh) and provides an electric signal (x.sub.EC) representative thereof.

[0129] The ITE-part may comprise a ventilation channel configured to allow an exchange of air between a residual volume between the eardrum and the ITE-part and the environment.

[0130] The hearing aid, e.g. the BTE-part (e.g. the DSP), further comprises an ear canal sound estimation unit configured to estimate sound in the ear canal (at least) in dependence of the ear canal electric input signal and providing an electric ear canal signal representative of at least a part of the sound in said ear canal. The ear canal sound estimation unit (ECSE, cf. FIG. 3) is configured to determine an electric anti-occlusion signal (x.sub.AOC, cf. FIG. 3) in dependence of the electric ear canal input signal of the (eardrum facing) ear canal input transducer (MEC).

[0131] The partition of functional tasks between the BTE-part and the ITE-part may differ depending on the specific application and functionality of the hearing aid. Some of the processing, for example the processing of the active occlusion cancellation system (AOCS) may be located in the ITE-part to avoid communication related to the eardrum facing microphone and and/or the eardrum facing loudspeaker (MEC, EC-SPK) to/from the signal processor (DSP) of the BTE-part. Thereby the electric interface (IC) between the BTE- and ITE-parts may be simplified.

[0132] The hearing aid (HD) (here the BTE-part) further comprises two (e.g. individually selectable) wireless receivers (WLR.sub.1, WLR.sub.2) for providing respective directly received auxiliary audio input and/or control or information signals. The wireless receivers may be configured to receive signals from another hearing device (e.g. of a binaural hearing system) or from any other communication device, e.g. telephone, such as a smartphone, or from a wireless microphone or a T-coil, or a separate dedicated processing unit. The wireless receivers may be capable of receiving (and possibly also of transmitting) audio and/or control or information signals. The wireless receivers may be based on Bluetooth or similar technology (e.g. UWB) or may be based on near-field communication (e.g. inductive coupling).

[0133] The BTE-part comprises a substrate SUB whereon a number of electronic components (MEM, FE, DSP) are mounted. The BTE-part comprises a configurable signal processor (DSP) and memory (MEM) accessible therefrom. In an embodiment, the signal processor (DSP) form part of an integrated circuit, e.g. a (mainly) digital integrated circuit.

[0134] The hearing aid (HD) exemplified in FIG. 2A represents a portable device and further comprises a battery (BAT), e.g. a rechargeable battery, for energizing electronic components of the BTE-part and possibly the ITE-part.

[0135] The hearing aid (e.g. the processor (DSP)) may be adapted to provide a frequency dependent gain and/or a level dependent compression and/or a transposition (with or without frequency compression) of one or more frequency ranges to one or more other frequency ranges, e.g. to compensate for a hearing impairment of a user. The hearing aid may comprise a front-end processing unit (FE) for handling substantially analogue signals, e.g. to/from the input and output transducers.

[0136] The active occlusion cancellation system is further described in connection with FIGS. 3 and 4 and 5B, 5C.

[0137] FIG. 2B shows an embodiment of an ITE-style hearing aid comprising an occlusion cancellation system according to the present disclosure. The embodiment of FIG. 2B is similar to the embodiment of FIG. 2A, except that the essential components of the hearing aid are located in an ITE-part. The hearing aid (HD) comprises or consists of an ITE-part comprising a housing (Housing), which may be a standard housing aimed at fitting a group of users, or it may be customized to a user's ear (e.g. as an ear mould, e.g. to provide an appropriate fitting to the outer ear and/or the ear canal). The housing schematically illustrated in FIG. 2B has a symmetric form, e.g. around a longitudinal axis from the environment towards the ear drum (Eardrum) of the user (when mounted), but this need not be the case. It may be customized to the form of a particular user's ear canal. The hearing aid may be configured to be located in the outer part of the ear canal, e.g. partially visible from the outside.

[0138] To minimize leakage of sound (played by the hearing aid towards the ear drum of the user) from the ear canal, a good mechanical contact between the housing of the hearing aid and the Skin/tissue of the ear canal is aimed at. In an attempt to minimize such leakage, the housing of the ITE-part may be customized to the ear of a particular user.

[0139] The hearing aid (HD) comprises a number Q of microphones M.sub.q, i=1, . . . , Q, here two (Q=2). The two microphones (M.sub.1, M.sub.2) are located in the housing with a certain (e.g. predefined) distance d between them, e.g. 8-10 mm, e.g. on a part of the surface of the housing that faces the environment when the hearing aid is operationally mounted in or at the ear of the user. The microphones (M.sub.1, M.sub.2) are e.g. located on the housing to have their microphone axis (an axis through the centre of the two microphones) point in a forward direction relative to the user, e.g. a look direction of the user (as e.g. defined by the nose of the user, e.g. substantially in a horizontal plane), when the hearing aid is mounted in or at the ear of the user. Thereby the two microphones are well suited to create a directional signal towards the front (and or back) of the user. The microphones are configured to convert sound (S.sub.1, S.sub.2) received from a sound field S around the user at their respective locations to respective (analogue) electric signals (s.sub.1, s.sub.2) representing the sound. The microphones are coupled to respective analogue to digital converters (AD) to provide the respective (analogue) electric signals (s.sub.1, s.sub.2) as digitized signals (x.sub.1, x.sub.2). The (digitized) electric input signals (x.sub.1, x.sub.2) are fed to a digital signal processor (DSP) for processing the audio signals (x.sub.1, x.sub.2), e.g. including one or more of spatial filtering (beamforming), (e.g. single channel) noise reduction, compression (frequency and level dependent amplification/attenuation according to a user's needs, e.g. hearing impairment), spatial cue preservation/restoration, etc. The digital signal processor (DSP) may e.g. comprise appropriate filter banks (e.g. analysis as well as synthesis filter banks) to allow processing in the frequency domain (individual processing of frequency sub-band signals). The digital signal processor (DSP) may e.g. comprise an ear canal sound estimation unit (ECSE) configured to estimate sound in the ear canal originating from the user's voice and to provide an electric anti-occlusion signal (x.sub.AOC, see e.g. FIG. 3) according to the present disclosure. The digital signal processor (DSP) is configured to provide a processed signal (x.sub.HAC) comprising a representation of the sound field S (e.g. including an estimate of a target signal therein). The processed signal (x.sub.HAC) is fed to an output transducer (here a standard hearing aid loudspeaker (HA-SPK), e.g. via a digital to analogue converter (DA), for conversion of the processed (digital electric) signal (x.sub.HAC) (or analogue version s.sub.HAC) to a sound signal S.sub.AC. In a specific anti-occlusion mode of operation according to the present disclosure the processed (hearing loss compensated) signal (x.sub.HAC) may comprise a compensation of the attenuation provided by the anti-occlusion cancellation system according to the present disclosure.

[0140] The hearing aid comprises an active occlusion cancellation system (AOCS in FIG. 3) according to the present disclosure. In addition to the ear canal sound estimation unit (ECSE) mentioned above, the active occlusion cancellation system further comprises an ear canal input microphone (MEC) located in the ITE-part and configured to provide an electric ear canal input signal (x.sub.EC) representing sound in the ear canal, when the user wears the hearing aid. The active occlusion cancellation system further comprises a second output transducer (EC-SPK) located in the ITE-part configured to play sound to the user and to provide the acoustic anti-occlusion signal (S.sub.AOC) in dependence of the electric anti-occlusion signal (x.sub.AOC). In the embodiment of FIG. 2B, the electric anti-occlusion signal (x.sub.AOC) is fed to the second output transducer (EC-SPK) via a digital to analogue converter (DA), for conversion of the processed (digital electric) signal (x.sub.AOC) to an analogue version (s.sub.AOC). The second output transducer (EC-SPK) may be specifically adapted to play low frequency sound, e.g. at frequencies below a threshold frequency, e.g. smaller than or equal to 1 kHz, or smaller than or equal to 600 Hz.

[0141] The hearing aid (HD) further comprises an energy source, e.g. a battery (BAT), e.g. a rechargeable battery, for energizing the components of the device.

[0142] FIG. 3 shows a simplified block diagram of an embodiment of a hearing aid comprising a first embodiment of an active anti-occlusion cancellation system according to the present disclosure. The hearing aid (HD) is configured to be worn by a user at or in an ear of the user. The hearing aid comprises an ITE-part adapted for being located at or in an ear canal of the user. The hearing aid comprises at least one first input transducer (here a microphone M) configured to pick up sound (S) at the hearing aid and to provide corresponding at least one first electric input signal (x) representing sound. The hearing ad comprises a hearing aid processor (HLC) configured to provide a processed signal (x.sub.HA) in dependence of the at least one electric input signal (x). The hearing aid comprises a first output transducer (HA-SPK) (here a loudspeaker) configured to play sound (S.sub.HAG) to the user in dependence of said processed signal (x.sub.HA), or a signal dependent thereon (x.sub.HAC).

[0143] The hearing aid further comprises an active occlusion cancellation system (AOCS) for providing an acoustic anti-occlusion signal (S.sub.AOC) configured to cancel or diminish a sense of occlusion of the user when the user is speaking, or chewing, or otherwise using his or her voice or facial bones or flesh, e.g. jaws (such activity providing the occluded sound S.sub.OC, see e.g. FIGS. 2A, 2B, 4). The active occlusion cancellation system (AOCS) comprises an ear canal input transducer (here a microphone (MEC)) located in the ITE-part and configured to provide an electric ear canal input signal (x.sub.EC) representing sound (S.sub.MEC) in the ear canal, when the user wears the hearing aid. The sound (S.sub.MEC) picked up by the ear canal microphone (MEC) is a sum of contributions from the two output transducers (HA-SPK, EC-SPK) and the occluded sound (S.sub.OC, and possible further sound directly propagated (e.g. leaked) from the environment), cf. symbolic summation unit (+) in the residual volume (Res. vol) receiving dashed bold arrows from the mentioned sources and providing a resulting input to the ear canal microphone (MEC) in FIG. 2B). The hearing aid (e.g. the active occlusion cancellation system (AOCS)) further comprises an ear canal sound estimation unit (ECSE) configured to estimate sound in the ear canal originating from the user's voice, etc., and to provide an electric anti-occlusion signal (x.sub.AOC) in dependence of the electric ear canal input signal (x.sub.EC) and the processed signal (x.sub.HA). The active occlusion cancellation system (AOCS) further comprises a second (anti-occlusion) output transducer (EC-SPK) located in the ITE-part and configured to play anti-occlusion sound (S.sub.AOC) to the user and to provide the acoustic anti-occlusion sound signal in dependence of the electric anti-occlusion signal (x.sub.AOC). The ear canal sound estimation unit (ECSE) is further configured to provide a compensated processed signal (x.sub.HAC) in dependence of the electric ear canal input signal (x.sub.EC) and the processed signal (x.sub.HA). The compensated processed signal (x.sub.HAC) is compensated by an amount corresponding to the part of the sound (S.sub.HAC) from the hearing aid loudspeaker (HA-SPK) that is cancelled by the acoustic anti-occlusion signal (S.sub.AOC). Such compensation is described in a number of prior art documents, e.g. US2008063228A1, or EP3588985A1. Thereby a mixture of the sound played by the (first) hearing aid loudspeaker (HA-SPK) and the (second) anti-occlusion loudspeaker (EC-SPK) ideally cancels (and in practice attenuates) the occluded sound (S.sub.OC) in the ear canal (e.g. in an occluded (or residual) volume between the ITE-part and the eardrum of the user).

[0144] In the embodiment of FIG. 3, the active occlusion cancellation system (AOCS) comprises the ear canal sound estimation unit (ECSE), the ear canal microphone (MEC) and the anti-occlusion loudspeaker (EC-SPK). In the embodiment of FIG. 3, the hearing aid processor (HLC) and the ear canal sound estimation unit (ECSE) are implemented in a digital signal processor (DSP) of the hearing aid (HD).

[0145] FIG. 4 shows a simplified block diagram of an embodiment of a hearing aid comprising a second embodiment of an active anti-occlusion cancellation system according to the present disclosure. The embodiment of FIG. 4 is similar to the embodiment of FIG. 3 (comprises the same functional blocs and input-output units). But in addition, the embodiment of FIG. 4 comprises two (at least one) input transducers (microphones M1, M2), and a beamformer filtering unit (BFU) connected to the input transducers (M1, M2) and the hearing aid processor (HLC). Further, in the exemplary embodiment of FIG. 4, the ear canal sound estimation unit (ECSE) is partitioned in a forward path compensation unit (OCMP) and an occluded sound control unit (OSCU). The forward path compensation unit (OCMP) is configured to provide that the compensated processed signal (x.sub.HAC) is compensated by an amount corresponding to the part of the sound (S.sub.HAC) from the hearing aid loudspeaker (HA-SPK) that is cancelled by the acoustic anti-occlusion signal (S.sub.AOC) provided by the anti-occlusion loudspeaker (EC-SPK). The forward path compensation unit (OCMP) is configured to provide the compensated processed signal (x.sub.HAC) in dependence of the forward path compensation control signal (HA-OC) provided by the occluded sound control unit (OSCU) in dependence of electric ear canal input signal (x.sub.EC) from the ear canal microphone (MEC) (or from a signal originating therefrom) and the processed signal (x.sub.HA) from the hearing aid processor (HLC).

[0146] FIG. 4 shows a simplified block diagram of an embodiment of a hearing aid comprising an active occlusion cancellation system according to the present disclosure. The hearing aid (HD) may be adapted for being located at or in an ear of a user. The hearing aid comprises a forward path for processing an audio input signal and providing a (preferably) improved, processed, signal intended for presentation to the user. The forward path comprises first and second microphones (M1, M2), configured to pick up environment sound (S) from the environment around the user when the user is wearing the hearing aid (HD). The two microphones provide respective (e.g. analogue or digitized) electric input signals (x.sub.1, x.sub.2) representative of the environment sound. The forward path further comprises (an optional) directional system (BFU) implementing one or more beamformers and providing one or more beamformed signals, here beamformed signal (x.sub.BF). The forward path further comprises a hearing aid signal processor (HLC) for processing the beamformed signal (x.sub.BF) and providing a processed signal (x.sub.HA), e.g. configured to compensate for a hearing impairment of the user. The forward path further comprises a loudspeaker (HA-SPK) connected to a loudspeaker sound outlet of the hearing aid and configured to provide an output sound (S.sub.HAC) to an eardrum (Eardrum) of the user in dependence of the processed signal (x.sub.HA) or a signal (x.sub.HAC) originating therefrom.

[0147] The hearing aid (HD) further comprises an active occlusion cancellation system (AOCS) (cf. dotted outline in FIG. 4) for providing an acoustic anti-occlusion signal (S.sub.AOC) configured to cancel or diminish a sense of occlusion of the user when the user is speaking or otherwise using his or her voice, or jaws, etc. The active occlusion cancellation system (AOCS) comprises an ear canal input transducer (here microphone MEC) configured to provide an electric ear canal input signal (x.sub.EC) representing sound in the ear canal, when the user wears the hearing aid. The active occlusion cancellation system (AOCS) further comprises an ear canal sound estimation unit (ECSE) configured to estimate sound in the ear canal in dependence of the electric ear canal input signal (x.sub.EC) and to provide an electric anti-occlusion signal (x.sub.AOC). The ear canal sound estimation unit (ECSE) may additionally (as also illustrated in FIG. 3) receive the processed signal (x.sub.HA), and be configured to estimate sound in the ear canal originating from the user's voice, etc., in dependence of the electric ear canal input signal (x.sub.EC) as well as the processed signal (x.sub.HA). The active occlusion cancellation system (AOCS) further comprises a second (separate) output transducer (here a loudspeaker (EC-SPK) configured to provide the acoustic anti-occlusion signal in dependence of (based on) the electric anti-occlusion signal (x.sub.AOC).

[0148] Depending on the design of the anti-occlusion system, the forward path may also include compensation for the attenuation that may be introduced by the anti-occlusion feedback loop. The anti-occlusion system attenuates the signal (x.sub.EC) that is picked up by the ear canal input transducer (MEC), including the desired signal from the forward path of the hearing aid (comprising amplified environment sound to be presented to the user). Hence, it may be beneficial to compensate the signal of the forward path. The compensation is in the embodiment of FIG. 4 provided by forward path compensation unit (OCMP) as indicated above.

[0149] The hearing aid may further comprise an own voice detector (OVD) providing an own voice control signal (OVC) indicative of whether or not or with what probability a current input signal comprises the ser's own voice. The own voice control signal may be used as input to the active occlusion cancellation system (AOCS), e.g. to activate or deactivate the system. Thereby the active occlusion cancellation system may be enabled when the user's own voice is present (or present with a probability above a threshold value (e.g. 50%)), and disabled when not. Own voice control of the active occlusion cancellation system (AOCS) may be used in all other embodiments of the hearing aid of the present disclosure.

[0150] The hearing aid (HD) may e.g. be partitioned in a BTE-part (BTE), and ITE-part (ITE) and an (inter)connecting element (IC) as e.g. illustrated in FIG. 1 and FIG. 2A. The (first) microphones (M1, M2, denoted M.sub.BTE1, M.sub.BTE2 in FIG. 2A) may be located in the BTE-part (as in FIG. 2A) or in the ITE-part (s in FIG. 2B) or distributed between the BTE-part and the ITE-part. The ear canal microphone (MEC) may e.g. be located in the ITE-part facing the ear drum (as illustrated in FIG. 1, 2A, 2B, 3, 4). The second (separate) loudspeaker (EC-SPK) may e.g. be located in the ITE-part (as illustrated in FIG. 1, 2A, 2B, 3, 4). The (first) normal hearing aid loudspeaker (HA-SPK) may e.g. be located in the BTE-part (cf. FIG. 2A) or other part different from the ITE-part. The (first) normal hearing aid loudspeaker (HA-SPK) may (alternatively) e.g. be located in the ITE-part (cf. FIG. 2B). The ear canal sound estimation unit (ECSE) may be located in the BTE-part or in the ITE-part, or distributed between the BTE-part and the ITE-part.

[0151] The hearing aid (HD) may, however, also be of a completely in the ear canal (CIC) type, see e.g. FIG. 2B. In such case, all components of the hearing aid (including the extra ear canal loudspeaker) may be located in the CIC-hearing aid.

[0152] The hearing aid may further comprise one or two earpieces (each for being located at least partially in an ear canal of the user) connected to a separate processing unit. At least some, such as all of the input and output transducers of a hearing aid according to the present disclosure may be located in an earpiece. At least the normal hearing aid loudspeaker (HA-SPK), the anti-occlusion loudspeaker (EC-SPK), and the ear canal microphone (MEC) may be located in an earpiece for a particular ear. The hearing aid microphone(s) (M, M1, M2) may also be located in an earpiece. The processing of the signals picked up by the microphones of the hearing aid may be performed in a separate processing unit. The processing related to generating the anti-occlusion signals (x.sub.AOC, x.sub.HAC, cf. FIG. 3, 4, 5B, 5C), e.g. embodied in the ear canal sound estimation unit (ECSE), may e.g. be performed in the earpiece.

[0153] FIG. 5A shows a conventional anti-occlusion system. .sub.A is a filter implementing an estimate of the transfer function (H.sub.A, cf. bold dashed arrow denoted H.sub.A) from the (electrical input to the) normal hearing aid loudspeaker (HA-SPK) to the (electrical output of the) ear canal microphone (MEC). The HLC-block is the hearing aid processor representing conventional hearing aid processing (HLC stands for hearing loss compensation) providing the processed signal (x.sub.HA) in dependence of an electric input signal (x) provided by a microphone (M). The filter (.sub.A) filters the processed signal (x.sub.HA) and the filtered signal (x.sub.HAS) is subtracted from the ear canal microphone signal (x.sub.EC) in a subtraction unit (1 followed by +). Thereby an estimate of the part of the ear canal microphone signal (x.sub.EC) originating from the normal hearing aid loudspeaker (HA-SPK) is subtracted from the ear canal microphone signal (x.sub.EC) resulting in compensated ear canal signal (x.sub.ECS) which is fed to a cancellation filter. The cancellation filter provides hearing aid processing modification signal (x.sub.ECSC), which is added to the processed signal (x.sub.HA) to provide a compensated output signal (x.sub.HAC). The compensated output signal (x.sub.HAC) is played to the eardrum by the normal hearing aid loudspeaker (HA-SPK).

[0154] FIG. 5B shows a first embodiment of an anti-occlusion system with two loudspeakers according to the present disclosure. The normal hearing aid loudspeaker (HA-SPK) may be used fundamentally as in a state-of-the-art hearing aid of FIG. 5A. The separate ear canal (anti-occlusion) loudspeaker (EC-SPK) may be specifically adapted for anti-occlusion and configured to play an anti-occlusion signal at the eardrum based on an anti-occlusion signal (x.sub.AOC) provided by the anti-occlusion processing block (denoted AO-HA-PRO in FIG. 5B). The anti-occlusion processing block provides output signals (x.sub.HAC, x.sub.AOC) to the normal hearing aid loudspeaker (HA-SPK) and to the separate ear canal (anti-occlusion) loudspeaker (EC-SPK), respectively, based on inputs (x.sub.HA, x.sub.EC) from the hearing aid processor (HLC, the processed signal (x.sub.HA) being based on the electric input signal (x) from an environment facing microphone (M)) and from the ear canal microphone (MEC), respectively. The AO-HA-PRO block in FIG. 5B may e.g. be embodied by the ear canal sound estimation unit (ECSE) in FIG. 3, 4 or 5C, generating the (possibly modified) hearing loss compensation signal (x.sub.HAC, possibly x.sub.HA) and an anti-occlusion signal (x.sub.AOC) based on the ear canal microphone signal (x.sub.EC) and the processed signal (x.sub.HA) from the hearing aid processor.

[0155] FIG. 5C shows a second embodiment of an anti-occlusion system with two loudspeakers (HA-SPK, EC-SPK) according to the present disclosure. The transfer function (H.sub.A) for sound from the (electrical input to the) normal hearing aid loudspeaker (HA-SPK) to the (electrical output from the) ear canal microphone (MEC), indicated by dashed arrow (H.sub.A) in FIG. 5C, is estimated by filter (.sub.A) (as in FIG. 5A). In other words, the transfer function (H.sub.A) may be assumed to include the transfer functions of the normal hearing aid loudspeaker and the ear canal microphone, respectively, as indicated by the bold dashed arrows in FIG. 5C. In addition to the distance between and properties of the involved components (HA-SPK, MEC), the transfer function (H.sub.A) is dependent on the ear canal acoustics (size of the ear, possible leakage paths, etc.). In the embodiment of FIG. 5C, the processed signal (x.sub.HA) from the hearing aid processor (HLC) is fed directly to the normal hearing aid loudspeaker (HA-SPK) for presentation to the user's eardrum. As in the state-of-the-art anti-occlusion system of FIG. 5A, the filter (.sub.A) of FIG. 5C filters the processed signal (x.sub.HA) and the filtered signal (x.sub.HAS) is subtracted from the ear canal microphone signal (x.sub.EC) in a subtraction unit (1 followed by +). Thereby an estimate of the part of the ear canal microphone signal (x.sub.EC) originating from the normal hearing aid loudspeaker (HA-SPK) is subtracted from the ear canal microphone signal (x.sub.EC) resulting in compensated ear canal signal (x.sub.ECS), which is fed to the cancellation filter (e.g. et ANC-feedback cancellation filter). The cancellation filter provides an anti-occlusion compensation signal (x.sub.AOC), which is fed to the separate (anti-occlusion) loudspeaker and played to the eardrum of the user to thereby reduce the perception of occlusion by the user. The cancellation filter, the filter (.sub.A) and the subtraction unit (1 followed by +) constitute or form part of an ear canal sound estimation unit (ECSE) as indicated by the dashed rectangular enclosure (denoted ECSE) in FIG. 5C. The filter (.sub.A) of FIG. 5C may be a fixed filter, wherein the transfer function (H.sub.A) is estimated in advance of use of the hearing aid (e.g. on a model or on a human being, e.g. the user). Alternatively, the filter coefficients of the filter (.sub.A) may be adaptively updated (e.g. after a power-up of the hearing aid, where the hearing aid(s) is (are) freshly mounted at the ears of the user, or regularly, such as continuously). Likewise, the cancellation filter may be a fixed filter or an adaptively updated filter based on an estimate of the transfer function (H.sub.B) from the (electrical input to the) separate ear canal loudspeaker (EC-SPK) to the (electrical output from the) ear canal microphone (MEC), as indicated by the bold dashed arrows in FIG. 5C.

[0156] In common of the embodiments of FIGS. 3, 4, 5B, and 5C, the hearing aid loudspeaker (HA-SPK) may e.g. be located in a part of the hearing aid located away from the ear canal of the user, e.g. in a part adapted for being located in or at or behind pinna. The hearing aid loudspeaker (HA-SPK) may, however, be located in an earpiece adapted for being fully or partially located in an ear canal of the user (e.g. together with the separate ear canal loudspeaker (EC-SPK), cf. e.g. FIG. 2B).

[0157] It is intended that the structural features of the devices described above, either in the detailed description and/or in the claims, may be combined with steps of the method, when appropriately substituted by a corresponding process.

[0158] As used, the singular forms a, an, and the are intended to include the plural forms as well (i.e. to have the meaning at least one), unless expressly stated otherwise. It will be further understood that the terms includes, comprises, including, and/or comprising, when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will also be understood that when an element is referred to as being connected or coupled to another element, it can be directly connected or coupled to the other element, but an intervening element may also be present, unless expressly stated otherwise. Furthermore, connected or coupled as used herein may include wirelessly connected or coupled. As used herein, the term and/or includes any and all combinations of one or more of the associated listed items. The steps of any disclosed method are not limited to the exact order stated herein, unless expressly stated otherwise.

[0159] It should be appreciated that reference throughout this specification to one embodiment or an embodiment or an aspect or features included as may means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the disclosure. Furthermore, the particular features, structures or characteristics may be combined as suitable in one or more embodiments of the disclosure. The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects.

[0160] The claims are not intended to be limited to the aspects shown herein but are to be accorded the full scope consistent with the language of the claims, wherein reference to an element in the singular is not intended to mean one and only one unless specifically so stated, but rather one or more. Unless specifically stated otherwise, the term some refers to one or more.

REFERENCES

[0161] US2008063228A1 (Hearworks) 13.03.2008 [0162] EP3588985A1 (GN Hearing) 01.01.2020 [0163] U.S. Pat. No. 8,229,127B2 (Oticon) 12.02.2009 [0164] EP3588981A1 (Oticon) 01.01.2020