JP4759014B2 - hearing aid - Google Patents

Description

  The present invention relates to a hearing aid and a method for acquiring and processing an acoustic signal in the hearing aid. More particularly, the invention relates to a hearing aid comprising a housing, at least one first microphone for receiving ambient sound, processing means for processing the signal from the first microphone and an output transducer, and acquisition of acoustic signals in the hearing aid. It relates to the processing method.

  It is well known that transducers such as microphones in electronic devices cause problems with wind noise.

  In hearing aids, this wind noise has two main causes. One is the direct effect of wind on the transducer membrane. The other is acoustic noise from turbulence around the head, outer ear, and hearing aid housing itself.

  In ears with normal hearing, the first cause is less noticeable because the membrane or eardrum is buried at the end of the ear canal deep in the inner ear.

  This is not the case for hearing aids. Conversely, in a hearing aid, the transducer is mounted as far as possible in order to achieve the optimum acoustic response of the transducer from various viewpoints such as frequency characteristics, sound pressure sensitivity, and directional phase characteristics.

  In many cases, the direct wind effect on the membrane causes the signal from the transducer to the signal processing circuit in the hearing aid to become very large and cause saturation. When a processing circuit section such as an analog / digital converter in a digital hearing aid, an amplification stage in the analog hearing aid, or even the microphone itself is saturated, the output signal generated by the hearing aid is impaired.

  Attempts have been made to reduce the problems associated with wind noise in hearing aids. US2002 / 0037088A mentions several prior art attempts, noting that it is well known to adapt the microphone opening to protect from the wind as much as possible to reduce, among other things, wind noise. Yes. However, this is usually incompatible with the desire to put each microphone outside as much as possible. In particular, the directional sensitivity achieved by using two or more microphones at each predetermined location of the hearing aid will be exacerbated if each microphone is not present outside. In addition, US 2002 / 0037088A does not detail how to protect these openings because other methods are employed rather than external means to overcome wind noise.

  US Pat. No. 3,875,349A is a hearing aid holding a first microphone having a spherical sensitivity characteristic, a second microphone having a directional sensitivity characteristic, and a switch for selectively switching an amplifier to one of the two microphones. Is provided. The switch can be automatically controlled in response to a signal. This document aims to solve different listening situations and does not address the effects of wind.

  US 5,201,006 A shows a hearing aid with a main microphone and an auxiliary microphone. The main microphone serves to provide the signal to be amplified. The auxiliary microphone is provided for the purpose of feedback correction and is adapted to receive sound through the auxiliary duct. The above sound is mainly generated in each part of the shell between the molded part and the ear canal wall. Arise from. Since the purpose is feedback correction, the auxiliary microphone is not intended to receive any ambient sound at all.

  The present invention aims to provide a hearing aid and method according to the opening paragraph and to overcome the above problems.

  According to the invention, the object is to provide a hearing aid according to the opening paragraph, wherein at least one additional microphone receiving the ambient sound to be amplified by the hearing aid is protected against wind effects during normal use of the hearing aid. This is achieved by a hearing aid characterized in that it is arranged at the location of the hearing aid housing.

  Additional microphones placed in locations that are protected against wind effects during normal use of the hearing aid can be used even in situations where the primary hearing aid microphone or each microphone is adversely affected by wind effects.

  According to a first preferred embodiment of the present invention, the hearing aid comprises a housing having a concave surface suitable for mounting behind the user's ear, and the at least one additional microphone is disposed in the recess of the hearing aid. By placing the microphone in this position, the microphone is positioned in the gap between the ear and the housing in use, thereby protecting the microphone from the wind.

  According to a second preferred embodiment, the hearing aid comprises a housing with a shell part suitable for partial insertion into the user's ear canal, wherein the at least one additional microphone is located adjacent to the shell part. Is done. By providing the microphone in the housing, the microphone is effectively protected from the wind.

  The arrangement in the microphone housing also allows a further preferred embodiment in which the hearing aid includes an electronic module and the additional microphone is arranged on the electronic module. This has the advantage of eliminating the wiring that needs to be routed from the electronic module to the additional microphone and, as a result, eliminating the need for delicate wiring operations that are typically performed manually.

  According to another embodiment, the additional microphone includes a port on the surface of the housing and a tube from the port to the electronics of the microphone in the housing. By using this tube, wind noise is reduced. The use of tubes also provides additional design options, such as special shapes to adjust the effect of wind noise on the microphone.

  Preferably, according to yet another embodiment, the tube has an inlet on the surface of the housing, the inlet being located in the concha when the hearing aid is positioned in the ear in which the hearing aid is used. And is positioned on the surface so that it is essentially located at the transition between the ear canal and the ear canal. By having the tube entrance at as deep a depth as possible in the ear, the ear itself also helps protect the additional microphone from the wind.

  In another preferred embodiment, the lower cutoff frequency of the additional microphone is substantially higher than the lower cutoff frequency of the at least one first microphone. This is beneficial because most of the noise spectrum energy from wind noise is found in the low frequency part of the audible spectrum and below. Therefore, the saturation caused by the signal from the microphone occurs at a higher level than the saturation caused by the signal from the main microphone. As a result, the saturation caused by these can be used to indicate the presence of wind noise.

  Preferably, the cut-off frequency of the additional microphone exceeds approximately 1 kHz. The cutoff frequency of the main microphone in modern hearing aids may be as low as 20 Hz. For this reason, the sensitivity of the additional microphone is a few dB lower in the case of a frequency of less than 1 kHz, depending on the expected frequency.

  In yet another embodiment, the hearing aid includes means for detecting saturation of the amplifier circuit and disabling the at least one first microphone if saturation is detected. Such detection can then be used to switch to an additional microphone.

  In another aspect, the present invention provides a first acoustic signal through an opening in a first microphone located at a first location of a hearing aid selected for a clear acoustic representation under conditions not exposed to the wind. Obtaining a second acoustic signal through an opening of a second microphone disposed at a second position of the hearing aid selected to be at least partially protected from being decently winded during normal use. Obtaining a wind-exposed condition by analysis of a noise level picked up by at least one of the first and second microphones, and processing the signal from the first microphone mainly in the non-exposed condition. Hearing aids, including selecting to process primarily signals from a second microphone when exposed to wind In to a method for acquiring and processing acoustic signals.

  As a result, it is achieved that a good rendering is maintained in a state where the first microphone is not exposed to wind effects.

  The first embodiment of the method includes selecting a directional microphone for the first microphone.

  As a result, it is achieved that the directivity sensitivity is maintained in a state where the main microphone is not exposed to the influence of wind.

  In a second embodiment, the method includes selecting a microphone for the second microphone that is less sensitive to low frequencies than the first microphone.

  As a result, it is achieved that the second microphone or a circuit connected thereto is saturated after the first microphone, so that the hearing aid becomes even less susceptible to wind.

  In another embodiment, the method includes customizing the hearing aid to fit the individual user's ear canal and to deepen the opening of the second microphone as feasible for the individual user.

  As a result, it is achieved that the second microphone is best protected against wind effects.

  In another embodiment of the invention, the method includes widening the opening of the second microphone so as to reduce any turbulence caused by crosswind.

  For a more effective understanding of the present invention, a detailed description is presented based on non-limiting exemplary embodiments illustrated in the drawings as follows.

  FIG. 1 shows a BTE hearing aid 1. The hearing aid includes a housing 2. The housing 2 essentially has four side surfaces, ie two substantially flat parallel side surfaces 3 and two curved side surfaces, which are composed of a convex side surface 5 and a concave side surface 4. The In use, a substantially flat side 3 is located between the pinna and the head. The convex side surface 5 is exposed behind the ear and the concave side surface 4 faces the transition between the outer ear and the head.

  A front microphone 6 and a rear microphone 7 are arranged on the convex side surface 5. Hereinafter, the front microphone 6 and the rear microphone 7 are collectively referred to as main microphones. In this regard, it should be noted that hearing aids without directional sensitivity had only one main microphone. The two main microphones 6 and 7 are spaced apart to obtain the directivity sensitivity of the hearing aid 1.

  As already mentioned, the main microphones 6 and 7 are arranged as far as possible in order to obtain good characteristics. Therefore, they are strongly influenced by the wind, and as a result, they are exposed to noise related to the wind.

  An additional microphone 8 is arranged on the concave side 4 of the hearing aid. In use, ie when the hearing aid 1 is placed behind the ear of the wearer, a hollow is formed by the auricle, the head, the boundary between them, and the concave side 4 of the hearing aid housing. The additional microphone 8 faces this hollow part, and as a result, it is efficiently protected from direct wind effects. In order to further suppress the influence of wind, the microphone opening of the second microphone 8 in the housing 2 may be flared (not shown).

  Experiments have shown that the frequency characteristic of the additional microphone 8 is the frequency characteristic of the main microphone, especially when considered as an alternative to the signal from the main microphones 6 and 7 which are affected by wind noise or distorted by saturation, for example. Even if it was lower, it was still acceptable.

  FIG. 2 shows another embodiment of the present invention. In the description of this embodiment, the same or corresponding mechanisms as those in FIG.

  The hearing aid of FIG. 2 includes an ITE housing that includes a top shell 9 and a hollow shell part 10 that is partially inserted into the ear canal 11 of the wearer and adapted to be held against the wall 11a of the ear canal. Have Typically, the face plate 9 is a standard element including the electronic module 12, but the hollow shell part 10 is manufactured individually for the user. For example, methods for producing custom shells by casting are known in the art. In a preferred embodiment, the shell part is manufactured by computer-aided manufacturing using a 3D printing method, hereinafter referred to as CAMISHA®. This method is described in WO 02 / 078233A and US 5,487,012A.

  The main microphones 6 and 7 are mounted in an electronic module 12 that protrudes slightly from the face plate 9. Preferably, the electronic module 12 includes all necessary signal processing circuitry except for the output transducer 13. The output transducer 13 is independently disposed in the hearing aid housing and is connected to the electronic module 12 by a flexible lead 14. Sound from the output transducer 13 is emitted through a transducer outlet tube 15 terminating in a transducer outlet plug 16 in the bottom 17 wall of the hollow shell part 10 facing the inner portion of the ear canal.

  In the embodiment of FIG. 2, the electronic module 12 further comprises an additional microphone 8. The additional microphone 8 is arranged in a portion of the electronic module 12 that is away from the face plate and does not face the outside. That is, the additional microphone constitutes an electronic component arranged in a part of the electronic module 12 and faces the space inside the hearing aid 1 in the assembled hearing aid 1. In the illustrated embodiment, the hearing aid housing includes a canal 18 from the inlet 20 on the surface of the shell part 10 to an additional microphone 8 in the housing. As a result, the effective voice port of the additional microphone is placed on the shell surface, while the electronic components of the additional microphone are placed in the electronic module.

  Tube 18 is preferably integrally formed with the shell part of the hearing aid housing. In the CAMISHA (registered trademark) manufacturing method, a computer model of the ear canal is set. In the cross-optimization procedure, the operator selects an electronic module and determines the optimal location and orientation of the electronic module and the shell within the ear canal. The shell is then adjusted and shaped to contact each side of the ear canal. However, the outer part of the shell does not touch the ear canal. The role of adjustment is to determine which part contacts the ear canal and to set the boundaries of the outer shell part.

  The CAMISHA® shell part 10 of the housing of the hearing aid 1 is manufactured separately, so that when the hearing aid is inserted into the mounting position in the ear canal 11, the hearing aid is included in the shell part 10 of the housing. It is possible to arrange the inlet 20 of the tube 18 just outside the boundary line 22 so that it is only slightly exposed. Thereby, the inlet 20 of the tube 18 can be arranged in the ear as deeply as possible without the inlet 20 being blocked by the ear canal wall 11a. A boundary line that separates the non-contact shell portion and the contact portion is indicated by a one-dot chain line 22 in FIG. The recessed portion of the entrance 20 achieves protection by the housing against direct exposure to the wind due to the combination of the hearing aid user's head and pinna. Preferably, as can be seen from FIG. 2, the inlet 20 forming the outer microphone opening is flared.

  The other end of the tube 18 terminates at an exit position 21 in the hearing aid corresponding to the position of the additional microphone 8. Since the additional microphone 8 is arranged on the electronic module 12, the additional microphone is in a suitable defined position with respect to the face plate 9. In this way, the tube 18 is integrally formed with the CAMISHA® shell part 10 in an individual computer assisted manufacturing.

  That is, by using the CAMISHA (registered trademark) shell part 10, the pipe 18 can be optimally arranged at each of the inlet 20 and outlet 21 positions. This eliminates the need for the entrance 20 to be retracted or deepened as deep as possible in the ear, where wind effects are least, and placed on the electronic module 12 to eliminate the need for additional wiring. This means that the outlet 21 is arranged to supply sound into the additional microphone 8. In the preferred embodiment, the inlet 20 leading to the microphone is widened. Widening the entrance also reduces noise from any crosswinds entering the tube.

Mentioned above this invention is only ITE and BTE hearing aids, one skilled in the art in CIC hearing aids (CIC = c ompletely i n the c anal), with leads to further microphone tube, placing a further microphone within the housing Will also be understood to be possible.

  Obviously, only a small amount of useful directivity information is available from the recessed microphone 8. Therefore, when a window noise or a saturation state is detected, switching directly to the additional microphone 8 involves sacrificing directivity information. However, most noise energy from wind-generated noise is low frequency. Thus, in one embodiment, high pass filtering is used to extract high frequency information from the main microphones 6 and 7, and low pass filtering extracts low frequency information from the additional microphone 8 with window noise removed. Used to do. This can be achieved in several ways, for example by introducing constant high and low pass filters when detecting saturation, or by smooth switching. As a result, it is possible to suppress the wind noise from the main microphones 6 and 7 while maintaining at least some directivity sensitivity. In other embodiments, the signals from each microphone can be combined or balanced according to a weighting factor and selected according to their prevailing state.

  Depending on the type of hearing aid, there are various criteria for detecting wind noise. One is a low frequency comparison between the signal from the additional microphone 8 and the signals from the main microphones 6 and 7. The other is detection of the saturation state of the analog / digital converter. Since the signal will switch randomly from a fully positive signal to a completely negative signal or vice versa, typically the slew rate can also be detected in a wind noise situation. Yet another criterion may be the detection of the low frequency portion of the signal from the main microphone that exceeds a predetermined threshold. Yet another criterion may be an uncorrelated noise level in the dual microphone portion of the directional microphone that exceeds a predetermined threshold.

  Since most signal energy of wind noise is low frequency, it is preferable to have different cutoff frequencies in the case of additional microphones, preferably compared to the main microphones 6 and 7, which are themselves matched to each other . This will cause the additional microphones to saturate much later than the main microphone even if they are exposed to the same noise.

Some typical positions of the microphones in the BTE hearing aid (BTE = b ehind- t he- e ar) is a schematic side view showing in cross-section. Typical positions of the microphones in ITE hearing aid (ITE = i n- t he- e ar) is a partial cross-sectional view schematically showing.

Claims (7)

A housing having a curved side including a convex side and a concave side, at least one first microphone receiving ambient sound, a second microphone receiving ambient sound, and at least one of first and second microphones A hook- and- loop hearing aid including a processing means for processing a signal and an output transducer,
An opening of the first microphone is formed on the convex side of the hearing aid housing;
Hearing aids in cooperation with the head and the pinna of the user to be protected against the effects of wind during normal use of the hearing aid by the housing, the opening of the second microphone is formed in a concave side of the hearing aid housing Is ,
Ear form a hearing aid. The ear-hook type hearing aid according to claim 1, wherein the lower cutoff frequency of the second microphone is higher than the lower cutoff frequency of the at least one first microphone. The ear-hook type hearing aid according to claim 2, wherein the cutoff frequency of the second microphone exceeds 1 kHz. 4. The method according to claim 1, wherein the processing means detects saturation of the amplifier circuit and disables the at least one first microphone when saturation is detected. The ear-hook type hearing aid according to claim 1. A method for acquiring and processing an acoustic signal in an ear-hung hearing aid comprising a housing having a curved side surface including a convex side surface and a concave side surface ,
Through the opening of the first microphone disposed in the convex side of the earhook forms hearing aid is selected to a clear acoustic representation under conditions not exposed to wind, to obtain a first sound signal,
Located on the concave side of the ear-hook hearing aid selected to be at least partially protected from receiving decent winds during normal use by a housing that cooperates with the head and pinna of the hearing aid user through the opening of the second microphone, to obtain a second sound signal,
Detecting a condition exposed to wind by analysis of a noise level picked up by at least one of the first and second microphones ;
Processes mainly the signal from the first microphone under the conditions not exposed to wind, for processing signals from primarily the second microphone under the conditions exposed to wind, method. The method according to claim 5 , wherein a directional microphone is used as the first microphone. A second microphone, using a microphone low have sensitivity than the first microphone for low frequency, The method of claim 5.