KR20130063530A - Hearing aid adapted for suppression of wind noise - Google Patents

Abstract

The present invention provides a hearing aid (100) comprising a microphone, a signal processing unit, an electro-acoustic output transducer, a housing (101) and a windshield cover (102), the housing having a surface with microphone inlets (112, 113). And the windshield cover is configured to be attached to the housing to cover the microphone inlet and to direct the sound into the gap between the housing and the windshield cover so that sound is transferred from the environment to the microphone inlet, the first dimension of the cross section of the gap being The hearing aid is in the range of 0.15 mm to 0.5 mm, and the minimum distance along the gap from the microphone inlet to the opening of the gap towards the environment is at least 1 mm.

Description

Hearing aids configured to suppress wind noise {HEARING AID ADAPTED FOR SUPPRESSION OF WIND NOISE}

The present invention relates to hearing aids. More specifically, the present invention relates to a hearing aid for wind noise suppression.

In connection with the present invention, a hearing aid system should be understood as a system for mitigating hearing loss of a hearing impaired user. The hearing aid system may be monaural and include a single hearing aid or may be binaural and include two hearing aids.

In the context of the present invention, a hearing aid should be understood as a compact microelectronic device configured to be worn behind or inside a human ear of a hearing impaired user. Hearing aids include one or more microphones, microelectronic circuits including signal processors, and acoustic output transducers. The signal processor is preferably a digital signal processor. Hearing aids are included in casings suitable for fitting behind or inside a human ear.

Various types of hearing aids exist. One example is behind-the-ear (BTE) hearing aids. BTE hearing aids are worn behind the ear. More precisely, the housing containing the main electronics is worn behind the ear. Earplugs or earpieces for emitting sound to the hearing aid user are worn in the ear, such as in an ear conduit. In conventional BTE hearing aids, a sound tube is used because the output transducer, commonly referred to in the hearing aid terminology, is located in the housing of the electronics unit. In some modern hearing aids, since the receiver is placed in an earplug in the ear, a conductive member comprising an electrical conductor is used.

In the context of the present invention, wind noise is defined as being caused by pressure fluctuations in the hearing aid microphone due to turbulent air flow. In contrast, acoustic sound generated by wind is not considered wind noise in this specification because such acoustic sound is part of the natural environment.

Wind noise is a serious problem in hearing devices. Wind noise can reach levels of 100 dB sound pressure level (SPL), even larger. Thus, a hearing device user usually stops the user's hearing device in a windy state because the acoustic perception of the hearing device in a windy environment may be worse than without the hearing device. .

Depending on wind speed, wind direction for hearing devices, individual hair length, mechanical obstructions such as hats, and other factors, the magnitude and spectral content of wind noise may vary significantly. The causes and effects associated with noise can be found in "Wind Noise in Hearing Aids: Causes and Effects" by H. Dillon et al. "Sources of Wind Noise in Hearing Aids" (IHCON 2000) and I. Roe. Submitted to the Journal of the Acoustical Society of the United States.

Although methods have been proposed to counter wind noise using mechanical structural means, such means are usually too large or too bulky to be implemented in hearing aids.

In addition, this treatment typically increases the acoustic attenuation of the target sound.

It is therefore a feature of the present invention to provide a hearing aid that overcomes at least these disadvantages and improves wind noise suppression.

A first aspect of the invention provides a hearing aid according to claim 1.

A first aspect of the present invention provides a hearing aid having a windshield and a hearing aid housing that efficiently suppresses wind noise.

A second aspect of the invention provides a hearing aid according to claim 14.

A second aspect of the invention provides a hearing aid, in particular configured to suppress and reduce wind noise.

Other advantageous features are described in the dependent claims.

Further features of the present invention will become apparent to those skilled in the art from the following detailed description, which further describes the present invention.

According to the present invention, a hearing aid having a windshield and a hearing aid housing, which effectively suppresses wind noise, can be provided.

According to the present invention, it is particularly possible to provide a hearing aid configured to suppress wind noise and to be miniaturized.

According to the present invention, wind noise suppression can be increased without a decrease in hearing aid sensitivity.

1 is a perspective view of selected components of a hearing aid in accordance with an embodiment of the present invention.
FIG. 2 is a first perspective view of the windshield cover according to the embodiment of FIG. 1.
3 is a second perspective view of the windshield cover according to the embodiment of FIG. 1.
4 is a perspective view of the hearing aid housing according to the embodiment of FIG. 1.
5 shows typical measurements of the power spectrum as a function of frequency for the BTE hearing aid with windshield cover and the front microphone of a conventional BTE hearing aid when exposed to wind with a speed of 4 m / s. It is a figure which shows.
FIG. 6 shows typical measurements of power spectrum as a function of frequency for BTE hearing aids with windshield covers and rear microphones of conventional BTE hearing aids when exposed to wind with a speed of 4 m / s. It is a figure which shows.
7 is a fairly schematic cross-sectional view of the hearing aid according to the embodiment of FIG. 1.
8 is a fairly schematic cross-sectional view of a hearing aid in accordance with another embodiment of the present invention.

Preferred embodiments of the invention are shown and described by way of example. Indeed, the invention may be practiced in various embodiments, with some details of the various embodiments being apparent and varied within the invention. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not as restrictive.

Hearing aids in accordance with various aspects of the present invention have been found to significantly improve the suppression of wind noise over a wide frequency band.

It has been found that the ratio of wind noise suppression to acoustic attenuation can be improved by providing the hearing aid with a sound delivery channel for sound that is guided from the environment to the microphone inlet, and the air flow in the sound delivery channel is controlled by the microphone inlet. There is a laminar flow before reaching.

For hearing aids in accordance with various aspects of the present invention, it has been found that the ratio of wind noise suppression to acoustic attenuation can be improved by appropriately selecting the length of the sound transmission channel.

It has also been found that the design of the cross section of the sound delivery channel can optimize the ratio of wind noise suppression to acoustic attenuation.

Consider now a small diameter tube that is configured to transmit sound from the environment to the microphone inlet, the turbulent flow initiated at the opening of the tube for a normally occurring state (i.e., wind speed) cannot be maintained within the tube and has a shorter distance than the tube length. It is designed to develop into laminar flow in the rear. Such a tube prevents the onset of desirable turbulent flow around the microphone inlet, but picks up wind noise by still causing pressure fluctuations that the turbulent flow around the opening of the tube is efficiently delivered by the tube to the microphone inlet.

Consider now a tube with a significantly larger diameter in which the flow in the tube is laminar for a normal occurring state. Such a tube cannot prevent the onset of undesirable turbulence around the microphone inlet, but the pressure fluctuations developed by the turbulent flow around the tube opening will not be guided efficiently to the microphone inlet and will vanish.

Thus, a small diameter first tube is suitable for suppression of wind noise caused by turbulent wind flowing directly into the tube, while a larger diameter second tube is caused by turbulent wind flow at the opening of the tube. It is suitable to prevent the pickup.

Consider now a device having two parallel plates spaced to form a gap, the gap being configured to transmit sound from the environment to a microphone inlet positioned within the gap between the plates and at the center of one of the plates. . Such a device is suitable for suppressing wind noise caused by wind flowing perpendicular to the plane of the plate. Also, the plates may be suitable for suppression of wind noise generated by wind flowing along the plane of the plates when the dimensions are carefully selected as described below.

If the in-plane wind flow is perpendicular to the edges of the plates, first, the spacing between the plates needs to be small enough so that turbulent wind flow (for normal normal wind speeds) is not maintained within the gaps between the plates. Secondly, the lateral size (and thus the propagation distance) of the plates need to be large enough so that the turbulent flow at the plate edge is converted into laminar flow at the microphone inlet.

It has been found that the ratio of wind noise suppression to acoustic attenuation for wind flowing parallel and in-plane with the edges of the plates can be improved by increasing the lateral magnitude (and thus the propagation distance) of the plates. The reason is that the propagation of turbulence induced pressure fluctuations is good by the near-field model while most of the propagation of the target sound from the environment is well modeled by the far-field model. Because it is modeled, the attenuation of turbulence induced pressure fluctuations will vary considerably with the propagation distance.

It has generally been found that the acoustic attenuation of sound propagating in the sound delivery channel or under the windshield according to various embodiments of the present invention begins to increase significantly when the plate spacing is less than 0.15 mm. On the other hand, the propagation distance required for transitioning turbulent flow to laminar flow is determined according to the square of the plate spacing value. Thus, the preferred plate spacing value is selected from the range in which the acoustic attenuation is limited and the range in which the flow is quickly converted to laminar flow for normal normal generated wind speed.

For the flow between two parallel plates, the distance L needed to convert the turbulent flow into a laminar flow is given by:

L = h ² v / (8υ)

Where h is the spacing between the two plates, v is the flow velocity (i.e. wind speed here) and υ is the kinematic viscosity of the air.

According to various embodiments of the present invention, it has been found that for propagation distances up to at least 10 mm, the acoustic attenuation of sound propagating in the gap remains small. Thus, a distinct advantage of hearing aids according to the present invention is that wind noise suppression can be increased without a decrease in hearing aid sensitivity.

Referring first to FIG. 1, there is shown a selected portion of a hearing aid 100 in accordance with a first embodiment of the present invention. The hearing aid 100 includes a housing portion 101, a windshield cover 102, a connector portion 103, and an earpiece (not shown). The housing portion 101 includes two microphones, a microelectronic circuit including a signal processor, a sound output converter, a toggle switch 104 and a push button 105. The connector portion 103 is configured to transmit the acoustic signal from the acoustic output transducer to the earpiece and toward the eardrum of the user wearing the hearing aid. The windshield cover is configured to protect the microphone inlet from dust and moisture and to suppress wind noise. The hearing aid housing 101 and the windshield cover 102 are configured to form side openings 118a and 118b when the windshield cover is attached to the hearing aid housing (similar openings are formed on opposite sides of the hearing aid housing). ). The opening is configured such that sound is delivered into the gap between the hearing aid housing and the windshield cover. The front indent (119) is configured to remove the windshield cover from the hearing aid housing using a simple tool.

Referring now to FIG. 2, there is shown a first perspective view of a windshield cover 102 according to a first embodiment of the present invention. The windshield cover has a convex side 106 configured to face away from the hearing aid housing (not shown) and a hole 107 configured to allow the user to access the toggle switch 104 of the hearing aid housing.

Referring now to FIG. 3, there is shown a second perspective view of a windshield cover 102 according to a first embodiment of the present invention. The windshield cover has a concave side 108 configured to face in a direction towards the hearing aid housing (not shown). The concave side 108 has protrusions 109a, 109b, 110a, 110b configured to snap fasten the windshield cover onto the hearing aid housing. The concave side also has columnar structures 111a and 111b and protrusions 122 configured to assist in guiding the windshield cover to the correct position when mounting the windshield cover on the hearing aid housing.

Referring now to FIG. 4, there is schematically shown a hearing aid housing 101 according to a first embodiment of the present invention. The hearing aid housing 101 has four indents 109c, 109d, 110d configured to snap fit with two microphone inlets 112, 113 and corresponding protrusions 109a, 109b, 110a, 110b of the windshield ( One not shown). The hearing aid housing has a hole 111d (one not shown) configured to receive the columnar structures 111a and 111b of the windshield cover and a rectangular indent 120 for receiving the protrusion 122 of the windshield cover. Has The banded protrusions 114 and other protrusion structures 115 positioned between the microphone inlets are uniformly defined between the concave side 108 of the windshield and the surface regions 116a and 116b of the hearing aid housing 101. work together to ensure clearance. The protruding structure 115 surrounds the toggle switch 104 and includes an indent 110d (one not shown) and a hole 111d (one not shown). Surface regions 116a and 116b form surfaces in which sound propagates along the microphone inlets 112 and 113 from the surrounding environment. Surface areas 116a and 116b and protruding structures 114 and 115 are surrounded by rim 117. The rim is configured such that openings 118a and 118b are formed when the windshield cover is snapped onto the hearing aid housing. Indent 120 allows the windshield cover to be easily removed from the hearing aid using a tool. The gap between the surface areas 116a and 116b of the hearing aid housing and the windshield cover 102 is 0.3 mm.

In a variation of the first embodiment of the invention, the gap between the surface areas 116a and 116b of the hearing aid housing and the windshield cover 102 is in the range of 0.15 mm to 0.5 mm, preferably in the range of 0.20 mm to 0.35 mm to be. Due to this gap distance, the air flow under the windshield cover, which is behind the short propagation distance, is in fact laminar to the normal occurring wind speed, and the acoustic attenuation of the sound caused by the propagation under the windshield cover is small.

According to a first embodiment of the invention, in the gap between the windshield cover 102 and the hearing aid housing 101 along the gap from the openings 118a and 118b to the corresponding microphone inlets 112 and 113. The minimum distances that follow are 2 mm each. In this specification, the term “minimum distance along the gap” should be interpreted as the shortest distance between the edge of the microphone inlet and the corresponding opening, the opening corresponding to the surrounding environment and formed by the edge of the windshield cover and the hearing aid housing. do.

In a variant of the first embodiment of the present invention, the minimum distance along the gap is at least 1 mm, at least 2 mm, or in the range of 1 mm to 3 mm (ie larger than 1 mm and smaller than 3 mm). It has surprisingly been found that this relatively limited gap distance significantly improves wind noise reduction.

For some reason it is advantageous to increase the guard distance along the gap. First, the air flow in the gap is laminar when reaching the microphone inlet at higher wind speeds as described above. Second, the damping of the turbulence induced pressure fluctuations formed along the edge of the windshield is greatly increased with distance. Finally, the pressure fluctuations caused by an uncorrelated turbulent vortex formed along the edge of the windshield cancel at least in part from each other at the microphone inlet and the efficiency of this offset generally increases with the minimum distance along the gap, This is because the offset of the two uncorrelated turbulent vortices is optimal when the distance between the microphone inlet and each vortex is equal. On the other hand, it has been found that the embodiment where the minimum distance is reduced to 1 mm provides a good compromise for high wind noise suppression and flat frequency microphone response. In a specific variant of the first embodiment of the present invention, the gap distance is 0.3 mm and the minimum distance along the gap is 1.5 mm. According to the first embodiment of the present invention, the width of both openings 118a and 118b is 5 mm.

In a modification of the first embodiment of the present invention, separate openings 118a and 11b are not provided. Instead, the total length of the windshield defines the width of both openings.

In another variation of the first embodiment of the present invention, the width of the openings 118a and 118b is at least 2 mm, at least 3 mm or at least 5 mm. It is advantageous to have wide openings to prevent pressure fluctuations caused by turbulent flow around the openings from being dissipated instead of being efficiently guided to the microphone inlet. On the other hand, it has been found that embodiments having openings with a width, for example, in the range from 2 mm to 5 mm, provide a good compromise for high wind noise suppression and flat frequency microphone response.

In another variation of the first embodiment of the present invention, the minimum distance along the gap between the openings 118a and 118b and the edges of the corresponding microphone inlets 112 and 113 varies due to a change in the hearing aid housing width.

In a modification of the first embodiment of the present invention, the widths of the openings 118a and 118b change with the change of the minimum distance, in order to ensure that the width of the opening for the length of this minimum distance remains substantially constant. to be.

Referring now to FIG. 5, a typical measurement of the power spectrum as a function of frequency for a BTE hearing aid with a windshield cover and a conventional BTE hearing aid in accordance with an embodiment of the present invention is shown. The measurement was performed while the hearing aid was exposed to the wind with a speed of 4 m / s. Both hearing aids had two microphones, and the power spectrum was obtained using the front microphones of the two hearing aids. The fact that a significant reduction in wind noise is achieved by a hearing aid with a windshield cover according to the invention is clearly shown in the drawings.

Referring now to FIG. 6, typical measurement results similar to those described with reference to FIG. 5 are shown, except that the rear microphones of the two hearing aids were used to acquire the power spectrum. It is clearly shown in the figure that the degree of achievable wind noise reduction varies with the microphone's positioning. It is also shown in FIGS. 5 and 6 that the typical power spectrum for BTE hearing aids according to the present invention is relatively insensitive to microphone positioning, but not for conventional BTE hearing aids.

Referring now to FIG. 7, there is shown a fairly schematic cross section of a hearing aid 100 according to a first embodiment of the present invention. A cross section of a plane perpendicular to the general longitudinal axis of the housing is shown, which is formed by a line connecting the first microphone inlet and the second microphone inlet and intersects with the first microphone inlet. The figure shows a cross section of the hearing aid housing 101, the windshield cover 102, the first microphone inlet 112 and the first microphone 121.

According to a first embodiment of the invention, the hearing aid housing 101 has a cross section with a circumference in a plane perpendicular to the overall longitudinal axis of the housing formed by a line connecting the first and second microphone inlets and the windshield cover 102 is configured to have a cross section in the plane described above having a length when disposed in the housing that is about 30% of the length of the housing perimeter.

In a variation of the first embodiment of the invention, the length of the windshield cover cross section is at least 30% of the length of the housing perimeter. Due to this, the minimum distance along the effective gap can be achieved even when the hearing aid housing has a relatively small housing perimeter. In another variation of the first embodiment of the invention, the length of the windshield cover cross section is less than 30% of the length of the housing perimeter. This type of windshield cover is desirable when a minimum distance along a relatively short gap is required to achieve a particular microphone frequency response.

According to a first embodiment of the invention, the hearing aid housing comprises an upper part and a lower part which fit together.

In another variation of the first embodiment of the present invention, the windshield cover extends in virtually all directions around the hearing aid housing, except for a gap opening formed between the ends of the windshield cover. According to another variant, the microphone inlet is positioned on the housing surface opposite the aperture opening to achieve the maximum achievable minimum distance between the microphone inlet edge and the corresponding aperture opening for a particular hearing aid housing. According to the invention, the gap opening is positioned on an upper surface of the hearing aid, ie on a surface opposite the surface of the hearing aid housing configured to be seated in the ear of the target hearing aid user.

Referring now to FIG. 8, a cross-sectional view of a hearing aid 200 in accordance with a second embodiment of the present invention is shown schematically. The figure shows the lower hearing aid housing portion 201, the upper hearing aid housing portion 202, the microphone inlet 212, the microphone 221, and the sound delivery channel 205. The sound delivery channel 205 allows sound to be directed from the environment to the microphone inlet 212. The sound delivery channel can propagate sound through the interior of the hearing aid housing, as opposed to propagation in the gap between the windshield cover and the outer surface of the hearing aid housing. Due to this, the size of the hearing aid housing can be minimized due to the need for a windshield cover. Another advantageous aspect is that the sound delivery channel can be freely shaped so that the minimum achievable distance between the microphone inlet and the opening of the sound delivery channel can be increased. The sound delivery channel has a length of 1.5 mm and has a cross section having a first dimension of 0.3 mm and a second dimension of 5 mm.

According to a variant of the second embodiment of the invention, the sound delivery channel has a length of at least 1 mm or a length in the range of 1 mm to 3 mm, the first dimension of the cross section being in the range of 0.15 mm to 0.5 mm, preferably It is in the range of 0.20 mm to 0.35 mm, and the second dimension of the cross section is at least 2 mm, at least 3 mm or at least 5 mm.

According to another variant of the second embodiment of the invention, the hearing aid comprises an insert forming a sound delivery channel and is also configured to position and hold the electronic component inside the hearing aid housing.

According to another variant of the first embodiment of the invention, the windshield has a small hole just above the microphone inlet. Surprisingly, it has been found that the hearing aid's microphone is less sensitive to vibrations, thereby making it less sensitive to feedback and at the same time suppressing wind noise. It has been found that holes with a diameter in the range of 0.15 mm to 0.30 mm are suitable.

Other variations and modifications to the structures and methods of the present invention will be apparent to those skilled in the art.

100: Hearing Aid
101: housing part
102: windshield cover
103: connector
104: toggle switch
105: push button
118a, 118b: side opening
119: front indent

Claims (20)

A hearing aid, comprising a microphone, a signal processing unit, an electro-acoustic output transducer, a housing and a windshield cover,
The housing has a surface with a microphone inlet,
The windshield cover is configured to attach to the housing, covering the microphone inlet and providing a clearance with the housing, thereby providing a conduit for sound transfer from the environment to the microphone inlet,
The average spacing between the housing and the windshield cover is in the range of 0.15 mm to 0.5 mm,
The minimum distance along the gap from the microphone inlet to the edge of the windshield cover is at least 1 mm,
hearing aid. The hearing aid as recited in claim 1, wherein the minimum distance along the gap from the microphone inlet to the edge of the windshield cover is greater than 1 mm and less than 3 mm. The hearing aid as recited in claim 1, wherein the windshield cover is configured such that sound is delivered into the gap between the windshield cover and the housing through an opening formed by the edge of the windshield cover and the housing. 4. The housing according to claim 1, wherein the housing comprises distance maintaining means, configured to secure a predetermined distance between the windshield cover and the housing by providing a support for the windshield cover. hearing aid. The hearing aid according to any one of claims 1 to 4, wherein the minimum distance along the gap from the microphone inlet to the edge of the windshield cover is at least 2 mm. The hearing aid as claimed in claim 1, wherein the minimum distance along the gap from the microphone inlet to the edge of the windshield cover is greater than 2 mm and less than 3 mm. The hearing aid according to claim 1, wherein the distance between the housing and the windshield cover is in the range of 0.20 mm to 0.35 mm. The hearing aid according to any one of claims 1 to 7, wherein the width of the gap at the edge of the windshield cover is at least 2 mm. The hearing aid according to any one of claims 1 to 8, wherein the width of the gap at the edge of the windshield cover is at least 3 mm. The hearing aid according to any one of claims 1 to 9, wherein the width of the gap at the edge of the windshield cover is at least 5 mm. The housing of claim 1, wherein the housing has a cross section with a perimeter in the plane, perpendicular to the overall longitudinal axis of the housing and intersecting the microphone inlet,
The windshield cover, when disposed in the housing, having a cross section in the plane having a total length greater than 30% of the length of the first perimeter. The hearing aid as recited in claim 11, wherein the overall longitudinal axis is defined by a line connecting the first microphone inlet and the second microphone inlet. The hearing aid according to claim 1, wherein the windshield cover extends substantially in all directions around the housing of the hearing aid, except for a gap opening formed between the ends of the windshield cover. Hearing aids configured to suppress wind noise,
Microphone inlet,
A sound delivery channel configured to direct sound from the environment to the microphone inlet,
The first dimension of the cross section of the sound delivery channel is in the range of 0.15 mm to 0.5 mm,
The second dimension of the cross section of the sound delivery channel is at least 2 mm,
The length of the sound delivery channel is at least 1 mm,
hearing aid. The hearing aid as recited in claim 14, wherein the length of the sound delivery channel is greater than 1 mm and less than 3 mm. The hearing aid according to claim 14 or 15, wherein the second dimension is at least 3 mm. The hearing aid according to any one of claims 14 to 16, wherein the first dimension of the cross section of the sound delivery channel is in the range of 0.20 mm to 0.35 mm. 18. The hearing aid according to any one of claims 14 to 17, wherein the second dimension of the cross section of the sound delivery channel is at least 5 mm. 19. The hearing aid according to any one of claims 14 to 18, wherein the sound delivery channel is formed as part of an insert configured to receive an electronic component inside the hearing aid housing. The hearing aid as recited in claim 14, wherein the sound delivery channel comprises at least one bend arranged to increase the length of the sound delivery channel.

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