JPH07264699A - Hearing aid - Google Patents

Abstract

PURPOSE:To provide the hearing aid which makes even a low volume easy to hear, and cancels environmental noise. CONSTITUTION:The device is provided with a feedforward type (FF type) noise canceller consisting of signal amplifiers 12L and 13L for hearing aid which extract the signal component in the prescribed frequency band from the signal from a microphone 6L at the amplification, amplitude/phase compensation means 15L outputting the signal from the microphone 6L through the amplitude and phase compensation processing, adder 16L for the output, speakers 17L and 18L outputting signals which are added by the adder by voice. The hearing aid may be constructed by providing a hearing aid means consisting of the FB-type noise canceller.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hearing aid, and more particularly to a feedforward noise canceller or a hearing aid equipped with a feedback noise canceller.

[0002]

2. Description of the Related Art In recent years, various types of hearing aids have been developed, and those having a configuration in which a unit containing an amplifier circuit or a battery and an earphone unit are used, or an amplifier circuit or a battery is housed in the same unit as the earphone unit. There is known a very small one that is worn on the ear.

[0003]

By the way, no matter what type of hearing aid, as long as it is a hearing aid, its output sound can be clearly heard, and the hearing of a normal hearing person who does not use the hearing aid can hear. It is desirable to hear such a natural feeling. In addition, since it is intended for the hearing impaired, it is necessary to avoid excessive sound pressure load on the eardrum to cause hearing fatigue to the user.

However, the sound amplified and output by the hearing aid includes, for example, not only the conversational sound that the user wants to hear, but also the surrounding environmental noise. Therefore, even if the volume (the hearing aid level) is increased when the conversation or the like cannot be heard well, the noise level is also amplified, that is, the easiness of hearing does not change when the S / N is considered. Moreover, increasing the volume causes an excessive sound pressure to be applied to the eardrum, resulting in deterioration of hearing ability and hearing fatigue. Further, by increasing the volume and using the sound, howling is likely to occur, and the clarity of the output voice is further reduced.

[0005]

SUMMARY OF THE INVENTION In view of such problems, it is an object of the present invention to provide a hearing aid that cancels ambient environmental noise and is easy to hear even at low volume.

Therefore, the hearing aid signal amplifying means for extracting and amplifying the signal component of the predetermined frequency band from the signal supplied from the microphone unit, and the amplitude and phase compensation processing for the signal supplied from the microphone unit. The output of the hearing aid signal amplifying means and the output of the amplitude / phase compensating means, and a speaker unit for outputting the signal added by the adding means as voice. A hearing aid is configured by providing a hearing aid formed by the above, that is, a hearing aid having a configuration of a feedforward type (FF type) noise canceller.

In this case, one microphone unit may be used as the microphone unit that outputs the signal to the hearing aid signal amplifying means and the microphone unit that outputs the signal to the amplitude / phase compensation means. .

Further, the first microphone unit, the hearing aid signal amplifying means for extracting and amplifying the signal component of the predetermined frequency band from the signal supplied from the first microphone unit, the speaker unit, and the speaker unit. Hearing means comprising a second microphone arranged in the vicinity and feedback circuit means for negatively feeding back the output of the second microphone to the output of the hearing aid signal amplifying means and supplying the feedback to the speaker unit, That is, feedback type (FB type)
The hearing aid is constructed by providing a hearing aid having a noise canceller.

Two hearing aids having the above-mentioned FF type or FB type noise canceller are provided for the left and right ears.

[0010]

By constructing the FF type or FB type noise canceller, the ratio of the voice to be heard to the environmental noise level, that is, the S / N is improved, and a hearing aid that is easy to hear even at a low volume can be realized. Further, if two systems of hearing aids are provided corresponding to the left and right ears, a hearing aid capable of so-called binaural listening is provided, and more natural listening can be performed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a hearing aid according to the present invention is shown in FIG.
5A and 5B, and the second embodiment will be described with reference to FIGS.

FIG. 1 is an external view of the hearing aid of the first embodiment, and 1 shows the entire hearing aid. Reference numerals 2L and 2R denote a left hearing aid portion and a right hearing aid portion which are attached to the left and right ears, and 3 denotes a box in which a battery, a power supply circuit, a hearing aid sound amplification circuit and the like are housed. The box 3 includes a power switch 3a for powering on / off, and volume operation knobs 8L, 8L for volume operation in the left hearing aid 2L and the right hearing aid 2R.
Operation means such as R is provided. It should be noted that one volume operation knob 8 may be provided for both left and right, and for users having different left and right hearing abilities, the balance may be adjusted by another adjusting section.

The tips of the left hearing aid 2L and the right hearing aid 2R are earpieces 5L, 5R, which are inserted into the ear canal when the hearing aid 1 is worn. Reference numerals 6L and 6R denote microphone units, which are attached to positions near the left and right ears, respectively, when worn, as can be seen from the figure. 9
L and 9R are long tube-shaped acoustic tubes, and end portions 9L
₂ is an opening, and the sound absorbing material 10 is filled inside.

The internal circuits and acoustic tubes of the box 3, the left hearing aid 2L and the right hearing aid 2R will be described with reference to FIG.
Since the left hearing aid 2L and the right hearing aid 2R have the same configuration, the left hearing aid 2L will be described and the right hearing aid 2 will be described.
Only R is shown in the figure (each part of the right auditory part 2R has the same part in the left auditory part 2L and the same number as "R").
Is attached).

As shown in FIG. 2, the operating power supply voltage V _CC is supplied from the power supply section 4 to the circuit sections corresponding to the left hearing aid section 2L and the right hearing aid section 2R. A microphone amplifier 11L amplifies the signal supplied from the microphone unit 6L. 12L is an equalizer for hearing aids, 13L is an amplifier, 14
L is a variable resistance part. Further, 15L is an amplitude / phase compensation circuit, 16L is an adder, 17L is a drive amplifier, 18
L is a speaker unit.

The signal amplified by the microphone amplifier 11L is supplied to the hearing aid equalizer 12L and the amplitude / phase compensation circuit 15L. The amplitude / phase compensation circuit 15L performs a compensation process on the input signal so that the speaker unit 18L outputs a sound having the same amplitude as the external sound but an opposite phase.

The hearing aid equalizer 12L extracts a signal to be heard by the hearing aid, for example, a signal in a band of about 300 Hz to 3 KHz. That is, it operates like a bandpass filter. The specific equalizing process is preferably variably set according to the hearing characteristics of the user. In some cases, a compressor or the like may be used to change the amplitude characteristic.

The output of the hearing aid equalizer 12L is the amplifier 1
After being amplified by 3 L and adjusted by the variable resistance unit 14 L according to the operation amount of the volume operation knob 8 L, the adder 1
It is supplied to 6L and added to the output of the amplitude / phase compensation circuit 15L. Then, the output of the adder 16L is applied to the speaker unit 18L via the drive amplifier 17L and output as sound.

As shown in the figure, the speaker unit 18L is attached to the acoustic tube 9L with its sound emitting surface 18L ₁ facing the inside of the tube. This acoustic tube 9L is the ear canal A
It is formed in a long tubular body formed to have an inner diameter W substantially the same as the inner diameter W ₀ thereof, and an earpiece 5L is attached to _one end 9L ₁ thereof. Also, the other end 9L ₂
Is an opening as a non-reflective end of sound, and a sound absorbing material 10 is filled in the pipe between the position near the speaker unit 18L and the end 9L ₂ .

The ear piece 5L attached to the end portion 9L ₁ of the acoustic tube 9L is formed of a flexible synthetic resin or the like into the shape shown in FIG.
It can be inserted into the inlet portion C of the. The inner diameter of the ear piece 5L is the inner diameter W ₀ substantially the same W ₁ of the inner diameter W and the ear canal of the acoustic tube 9 L.

Sound emitting surface 18L _{1 of the} speaker unit 18L
Is arranged so as to face the inside of the acoustic tube 9L substantially flush with the inner peripheral surface of the acoustic tube 9L. By doing so, the speaker unit 18L can be mounted without disturbing the acoustic impedance characteristics of the acoustic tube 9L. Become.

Then, in a state in which the tip of the earpiece 5L is inserted into the entrance portion C of the ear canal A and the acoustic tube 9L is attached, the end 9L ₂ which is a non-reflective end between the eardrum B in the ear canal A and the sound. The sound tube 9L serves as a sound path having a constant acoustic impedance because the parts up to and including the line have a substantially constant inner diameter.

With this configuration, the speaker unit 18L
The sound output from the both sides (end 9L ₁
Side and the end portion 9L ₂ side) and propagate as a plane wave. Of these, the sound waves that have reached the eardrum B and reflected are again the acoustic tube 9
Although it returns to the L side, since impedance matching is taken in the acoustic tube 9L, it is transmitted from the end portion 9L ₁ side to the end portion 9L ₂ side in the acoustic tube 9L without being reflected elsewhere. And it is gradually attenuated until it reaches the end 9 L _1, is almost the end 9 L ₁ silence. Due to the acoustic tube 9L and the speaker unit 18L, the earphone portion is configured as a non-reflective type in this embodiment.

FIG. 5 shows the frequency characteristic of this non-reflective earphone.
Is shown as a solid line. The alternate long and short dash line represents the frequency characteristic of the closed earphone used in the conventional hearing aid. As shown in the figure, the non-reflective earphones have flat characteristics down to a sufficiently low frequency range.
It shows that there is no leak in the coupling part with, and the fact that there is no leak is nothing but a large howling margin. In this case, the acoustic gain is 40 dB or more, and the size of the howling margin is verified. That is, in this embodiment, the howling margin is increased by using the non-reflective earphone, and the howling is less likely to occur.

The circuit configuration corresponding to the left hearing aid 2L and the left hearing aid 2L in the box 3 is the right hearing aid 2R.
Are formed in exactly the same way.

The noise canceling operation of the hearing aid 1 will be described. First, FIG. 3 shows the relationship between the gain (amplitude compensation) as a noise canceller and the eardrum sound pressure. The dotted line is the foreign sound level, the solid line is the amplitude / phase compensation circuit 15L, and when the phase of the sound output from the speaker unit 18L is opposite to the foreign sound, the one-dot chain line is positive for the foreign sound. The case where the phase output is performed from the speaker unit 18L (that is, the case where the noise canceller is not mounted) is shown.

With respect to the external sound at the level indicated by the dotted line, amplitude / phase compensation circuit 15L performs amplitude compensation so that the output of speaker unit 18L has the amplitude shown as a cancellation point in the figure, and the phase is reversed. It can be seen that the external sound can be canceled by performing the phase compensation on. It is also shown that howling eventually occurs when the amplitude (amplification gain as a hearing aid) increases without a noise canceller.

The compensation characteristic of the amplitude / phase compensation circuit 15L is compensated over a wide band of one decade or more, and can be canceled by an average of about 20 dB in a band of about 50 Hz to 1500 Hz. The output of the amplitude / phase compensation circuit 15L that performs such amplitude and phase compensation is given to the adder 16L as a feedforward signal,
Hearing aid signal, that is, equalizer 12L for hearing aid, amplifier 13
The S / N improvement by adding to the signal through the L and variable resistance unit 14L will be described with reference to FIG.

In FIG. 4, the dotted line is the external sound level, and the alternate long and short dash line is the equalizing characteristic of the hearing aid equalizer 12L. Now, without having a configuration (amplitude / phase compensation circuit 15L) as a noise canceller, the output of the hearing aid equalizer 12L is amplified and the speaker unit 18L is amplified.
When the sound is output from the speaker unit 18L
The thick line shows the characteristics of the eardrum sound pressure, including the external sound that comes directly into the ear without passing through the hearing aid (the thick line indicates the sound pressure that is almost the same as the sound pressure of the equalizer characteristic and the external sound level). Although shown as pressure, the sound pressure is actually set by the amplifier 13L and the variable resistance portion 14L). In the case of this thick line, the relative level of the voice (voice to be heard) with respect to external noise is, for example, 400 Hz.
Then, the level is indicated by a.

Now, consider the case where the outputs of the amplitude / phase compensation circuit 15L are added by the adder 16L as in the present embodiment. Then, by adding the outputs of the amplitude / phase compensation circuit 15L, an active cancellation effect of about 20 dB on average in the band of about 50 to 1500 Hz is obtained as described above, and the passive sound insulation of the external sound based on the shape of the earpiece 5L is achieved. With the added effect, 20 over almost the entire band
An attenuation characteristic of about dB can be obtained. This is indicated by a broken line in FIG.

At this time, the adder 16 from the original hearing aid sound, that is, the hearing aid equalizer 12L through the variable resistor 14L.
The characteristic of the sound component supplied to the L and output from the speaker unit 18L corresponds to the equalizing characteristic of the hearing aid equalizer 12L indicated by the alternate long and short dash line, but the external environmental sound is attenuated from the level indicated by the dotted line as indicated by the broken line. As a result, the relative level of the voice (the voice that the user wants to hear) with respect to the external noise becomes the level indicated by a + b at 400 Hz. That is, the S / N has been greatly improved.

As described above, in this embodiment, the external environmental sound is attenuated over the entire band in advance, and only the signal in the required band is amplified.
Can be significantly improved, and a hearing aid that is extremely easy to hear can be realized.

Further, since the S / N is greatly improved as described with reference to FIG. 4, even if the volume level is lowered to some extent, sufficient audibility can be obtained. For example, it is assumed that the volume control knob 8L is operated to change the variable resistance portion 14L, and the volume is reduced as indicated by the thick line in FIG. Here, assuming that a = b, in the case of a thick line, the S / N is about the same as the conventional one, that is, the easiness of hearing is about the conventional one, but the sound pressure burden on the eardrum is considerably reduced. .

In other words, in practice, when the volume level between the thick lines and is used, compared with the conventional hearing aid,
The S / N is improved and the burden on the eardrum can be eased. Furthermore, howling is effectively prevented by this noise canceling operation.

S / N by the above noise canceling operation
Of the left hearing aid 2L, right hearing aid 2R
It is also realized in.

Now, let us consider the point of obtaining a natural listening feeling by binaural listening. Originally, the sound pressure on the eardrum when the head is placed in a sound field having a flat frequency characteristic, that is, the frequency characteristic of the ear itself is generally a rise characteristic of about 10 dB when the sound pressure on the eardrum is 1 KHz or more. This is mainly attributed to the action of the pinna. Therefore, in the case of a hearing aid used near the auricle that causes this phenomenon, it is desirable that the free sound field frequency characteristic be flat.

Regarding this point, it can be seen that, in the present embodiment, the use of the non-reflection type earphone having the characteristics shown by the solid line in FIG. 5 is suitable for obtaining a natural hearing feeling. In other words, it is a device that is used near the auricle and is very close to nature, and the amplified voice is transmitted into the ear in an easily audible state.

In the left hearing aid 2L and the right hearing aid 2R, the microphone units 6L and 6R are mounted near the left and right ears, so that the binaural effect can be effectively obtained. It is possible to obtain a good sense of hearing that the external sound is heard by the ear without the localization being kept inside the head.

That is, in the hearing aid of this embodiment, the howling margin is increased as described above, the frequency characteristic is flat, the reflected sound in the ear canal is small, and the microphone units are attached to the left and right ears. The binaural listening with a natural feeling is realized by being close to each other, and S
By improving / N, it is possible to obtain a hearing aid voice that is easier to hear.

Next, a second embodiment of the present invention will be described. FIG. 6 is an external view of the second embodiment, and FIG. 7 is a configuration diagram. Thirty
Shows the entire hearing aid in the form of a headband, 31
Is a headband to be worn on the head. A housing is attached to the center (top of head) of the headband 31 to form a power supply unit 4 in which a battery and a power supply circuit are housed. Reference numeral 4a indicates a power switch. A left hearing aid 32L and a right hearing aid 32R are attached to both ends of the headband 31 so as to correspond to the left and right ears.

Reference numerals 33L and 33R denote storages in which amplifier circuits, speaker units, etc. are stored, and volume control knobs 8L and 8R are provided in the storages 33L and 33R. As shown in FIG. 7, the power supply unit 4 supplies the operating power supply voltage V _CC to the circuits in the storage units 33L and 33R.

In this case, the left hearing aid 32L and the right hearing aid 32
In R, as can be seen from FIG. 7, earpieces 5L and 5R are acoustic tubes 9L and 9L, respectively, as in the first embodiment.
It is attached to the ends 9L ₁ and 9R ₁ of R, and
The speaker units 18L and 15R are sound emitting surfaces 15L ₁ and 1
5R ₁ is mounted so as to face the inside of the acoustic tube 9L so as to be substantially flush with the inner peripheral surface of the acoustic tube 9L, that is, a non-reflective earphone is formed as in the first embodiment.

Microphone units 6R and 6L are attached to the left hearing aid section 32L and the right hearing aid section 32R, that is, the microphone unit 6 is placed near the ear when worn.
R and 6 will be located. Furthermore, the left hearing aid 32
Speaker units 18L and 18 are provided on the L and right hearing aids 32R.
Microphone units 7R and 7L in the vicinity of R
Are arranged.

The circuits inside the left hearing aid 32L and the right hearing aid 32R will be described with reference to FIG. The left hearing aid 32L
And the right hearing aid 32R have the same configuration, the left hearing aid 2
Only L will be described, and the right hearing aid 2R will be described only as an illustration (the same parts are denoted by the same reference numerals with "R" added).

Reference numeral 34L is an amplification and equalizer section, which performs equalizing processing for extracting a band of, for example, about 300 Hz to 3 KHz and amplification processing as hearing aid sound on the audio signal supplied from the microphone unit 6L. Reference numeral 35L is a variable resistance unit whose resistance value is adjusted by the volume operation knob 8L, 36L is a subtractor, 37L is a loop filter, 38L is a drive amplifier, and 39L is a microphone amplifier.

Microphone unit 6 of the left hearing aid 32L
The audio signal obtained at L is amplified and amplified by the amplifier / equalizer unit 34L to extract a signal in the desired band, and the output level is adjusted by the variable resistance unit 35L, and then supplied to the subtractor 36L.

The subtractor 36L includes a speaker unit 18
The signal picked up by the microphone unit 7L arranged near L is also amplified by the microphone amplifier 39L and supplied. Then, in the subtractor 36L, the variable resistance unit 1
The signal supplied from the microphone amplifier 39L is subtracted from the signal supplied from the 3L, and the subtracted output is supplied from the drive amplifier 38L to the speaker unit 18L via the loop filter 37L and is output as sound.

In other words, the external environmental noise is detected by the microphone unit 7L and a feedback loop is applied to the subtractor 36L as a negative feedback signal, and the external sound level is 1 / (loop gain).
Is attenuated to. Therefore, by the noise canceling action determined by the open loop gain, the foreign sound can be attenuated as shown by the broken line in FIG. 4 also in this embodiment.

By amplifying only the required band in the amplification and equalizer section 34L, the S / N can be remarkably improved as in the case of the first embodiment, and the S / N ratio can be improved. Even if the volume is lowered to some extent, the improvement makes it easy to hear, and the sound pressure burden on the eardrum can be alleviated. Of course, the noise canceling operation is performed in the same manner in the right hearing aid 32R,
These effects are obtained.

Also in this embodiment, by adopting a non-reflective type earphone and the above noise canceling operation, the howling margin is increased, and the left and right ears are not affected.
It goes without saying that the hearing aid of the system and the microphone units 6L and 6R are located in the vicinity of the left and right ears, so that a natural hearing feeling due to binaural listening can be obtained.

Although two embodiments have been described above, the present invention is not limited to these and various modifications can be made. For example, the shape is not limited to the headband type and the box-separated type as described above, but may be a left and right two-ear mounting type.

Although the non-reflective type earphone is adopted, the earphone type is not limited to this. Furthermore, in the first embodiment, the microphone units 6L and 6R are used for both the original sound collection of the hearing aid sound and the sound collection of the external environmental sound. Alternatively, a microphone unit may be provided.

In the embodiment, the binaural hearing aid is made possible by the left and right hearing aids. However, the noise canceller of the present invention can be applied to a hearing aid of a type that is worn only on one ear.

[0054]

As described above, the hearing aid of the present invention is
By mounting the circuit means which becomes the FF type or FB type noise canceller, the ratio of the voice to be heard to the environmental noise level, that is, S / N can be improved, and clear hearing aid can be obtained, and As a result, a hearing aid that is easy to hear even at a low volume can be realized, and the sound pressure burden on the eardrum can be reduced. In addition, a substantial howling margin can be widened accordingly.

In the case of constructing an FF type noise canceller, one microphone unit is used both as a microphone unit for outputting a signal to the hearing aid signal amplifying means and a microphone unit for outputting a signal to the amplitude / phase compensating means. By doing so, simplification of the configuration is realized.

If two hearing aids equipped with an FF type or FB type noise canceller are provided corresponding to the left and right ears, the hearing aid becomes binaural in addition to improving the S / N ratio and becomes more natural. This has the effect of enabling close listening.

[Brief description of drawings]

FIG. 1 is an external view of a hearing aid according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a configuration of a hearing aid according to the first embodiment.

FIG. 3 is an explanatory diagram of a relationship between sound pressure on an eardrum and output gain.

FIG. 4 is an explanatory diagram of a noise canceling operation according to the embodiment.

FIG. 5 is an explanatory diagram of frequency characteristics of the non-reflection type earphone of the embodiment.

FIG. 6 is an external view of a hearing aid according to a second embodiment of the present invention.

FIG. 7 is an explanatory diagram of a configuration of a hearing aid according to a second embodiment.

[Explanation of symbols]

 1,30 Hearing aid 2L, 31L Left hearing aid 2R, 31R Right hearing aid 3 Box 4 Power supply 4a Power switch 5L, 5R Earpiece 6L, 6R, 7L, 7R Microphone unit 8L, 8R Volume control knob 9L, 9R Sound tube 10 Sound absorption Material 11L, 11R Microphone amplifier 12L, 12R Hearing equalizer 13L, 13R Amplifier 14L, 14R, 35L, 35R Variable resistance part 15L, 15R Amplitude / phase compensation circuit 16L, 16R Adder 17L, 17R, 38L, 38R Drive amplifier 18L, 18R Speaker unit 31 Headband 34L, 34R Amplification and equalizer section 36L, 36R Subtractor 37L, 37R Loop filter

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[Procedure amendment]

[Submission date] July 20, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 4

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

FIG. 1 is an external view of the hearing aid of the first embodiment, and 1 shows the entire hearing aid. Reference numerals 2L and 2R denote a left hearing aid portion and a right hearing aid portion which are attached to the left and right ears, and 3 denotes a box in which a battery, a power supply circuit, a hearing aid sound amplification circuit and the like are housed. The box 3 includes a power switch 4a for powering on / off, and volume control knobs 8L, 8L for volume control in the left hearing aid 2L and the right hearing aid 2R.
Operation means such as R is provided. It should be noted that one volume operation knob 8 may be provided for both left and right, and for users having different left and right hearing abilities, the balance may be adjusted by another adjusting section.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction content]

The tips of the left hearing aid 2L and the right hearing aid 2R are earpieces 5L, 5R, which are inserted into the ear canal when the hearing aid 1 is worn. Reference numerals 6L and 6R denote microphone units, which are attached to positions near the left and right ears, respectively, when worn, as can be seen from the figure. 9
L and 9R are long tube-shaped acoustic tubes, and end portions 9L
₂ , 9R ₂ are openings, and the sound absorbing material 1 is inside.
0 is filled.

[Procedure amendment 4]

[Document name to be amended] Statement

[Name of item to be corrected] 0022

[Correction method] Change

[Correction content]

When the acoustic tube 9L is attached by inserting the tip portion of the earpiece 5L into the entrance portion C of the external auditory meatus A, the end portion 9L ₂ from the eardrum B in the external auditory meatus A to the non-reflective end of the acoustic tube. The sound tube 9L serves as a sound path having a constant acoustic impedance because the parts up to and including the line have a substantially constant inner diameter.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Name of item to be corrected] 0023

[Correction method] Change

[Correction content]

With this configuration, the speaker unit 18L
The sound output from the both sides in the acoustic tube 9 L (end 9 L ₁
Side and the end portion 9L ₂ side) and propagate as a plane wave. Of these, the sound waves that have reached the eardrum B and reflected are again the acoustic tube 9
Although it returns to the L side, since impedance matching is taken in the acoustic tube 9L, it is transmitted from the end portion 9L ₁ side to the end portion 9L ₂ side in the acoustic tube 9L without being reflected elsewhere. And it is gradually attenuated until it reaches the end 9 L _2, is almost the end 9 L ₂ silence. Due to the acoustic tube 9L and the speaker unit 18L, the earphone portion is configured as a non-reflective type in this embodiment.

[Procedure correction 6]

[Document name to be amended] Statement

[Name of item to be corrected] 0024

[Correction method] Change

[Correction content]

FIG. 5 shows the frequency characteristic of this non-reflective earphone.
Is shown as a solid line. The alternate long and short dash line represents the frequency characteristic of the closed earphone used in the conventional hearing aid. As shown in the figure, the non-reflective earphones have flat characteristics down to a sufficiently low frequency range.
A manifestation of that leakage of the coupling portion is not the addition of et not be made larger howling margin that there is no leakage. In this case, the acoustic gain is 40 dB or more, and the size of the howling margin is verified. That is, in this embodiment, the howling margin is increased by using the non-reflective earphone, and the howling is less likely to occur.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0042

[Correction method] Change

[Correction content]

In this case, the left hearing aid 32L and the right hearing aid 32
In R, as can be seen from FIG. 7, earpieces 5L and 5R are acoustic tubes 9L and 9L, respectively, as in the first embodiment.
It is attached to the ends 9L ₁ and 9R ₁ of R, and
Speaker units 18L and 18R are sound emitting surfaces 18L ₁ and 1
8R ₁ is mounted so as to face the inside of the acoustic tube 9L so as to be substantially flush with the inner peripheral surface of the acoustic tube 9L, that is, a non-reflective earphone is formed as in the first embodiment.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0043

[Correction method] Change

[Correction content]

Microphone units 6R and 6L are attached to the left hearing aid section 32L and the right hearing aid section 32R, that is, the microphone unit 6 is placed near the ear when worn.
R and 6L will be located. Furthermore, the left hearing aid 32
Speaker units 18L and 18 are provided on the L and right hearing aids 32R.
Facing the inside of the acoustic tubes 9L and 9R in the vicinity of R
Microphone unit 7R on the position, 7L are arranged.

[Procedure Amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0044

[Correction method] Change

[Correction content]

The circuits inside the left hearing aid 32L and the right hearing aid 32R will be described with reference to FIG. The left hearing aid 32L
And the right hearing aid 32R have the same configuration, the left hearing aid 3
Only the 2L will be described, and the right hearing aid 32R will be described only as an illustration (the same portions are denoted by the same reference numerals with "R").

[Procedure Amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0047

[Correction method] Change

[Correction content]

The subtractor 36L includes a speaker unit 18
A signal picked up by the microphone unit 7L arranged in the vicinity of L facing the inside of the tube is also amplified by the microphone amplifier 39L and supplied. And the subtractor 36L
Then, the signal supplied from the microphone amplifier 39L is subtracted from the signal supplied from the variable resistance unit 13L, and the subtraction output is passed through the loop filter 37L to the drive amplifier 3
It is supplied from 8L to the speaker unit 18L and is output as sound.

[Procedure Amendment 11]

[Document name to be amended] Statement

[Correction target item name] Explanation of code

[Correction method] Change

[Correction content]

[Explanation of reference signs] 1,30 Hearing aid 2L, 32L Left hearing aid 2R, 32R Right hearing aid 3 Box 4 Power supply 4a Power switch 5L, 5R Earpiece 6L, 6R, 7L, 7R Microphone unit 8L, 8R Volume control knob 9L, 9R Acoustic tube 10 Sound absorbing material 11L, 11R Microphone amplifier 12L, 12R Hearing equalizer 13L, 13R Amplifier 14L, 14R, 35L, 35R Variable resistance part 15L, 15R Amplitude / phase compensation circuit 16L, 16R Adder 17L, 17R, 38L, 38R drive amplifier 18L, 18R speaker unit 31 headband 34L, 34R amplification and equalizer section 36L, 36R subtractor 37L, 37R loop filter

[Procedure Amendment 12]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

[Procedure Amendment 13]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 6

[Correction method] Change

[Correction content]

[Figure 6]

[Procedure Amendment 14]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 7

[Correction method] Change

[Correction content]

[Figure 7]

Claims (4)

[Claims] 1. A hearing aid signal amplifying means for extracting and amplifying a signal component in a predetermined frequency band from a signal supplied from a microphone unit, and outputting a signal supplied from the microphone unit after amplitude and phase compensation processing. An amplitude / phase compensation means, an addition means for adding the output of the hearing aid signal amplification means and an output of the amplitude / phase compensation means, and a speaker unit for outputting the signal added by the addition means as a sound. A hearing aid comprising: 2. A microphone unit that outputs a signal to the hearing aid signal amplifying means and a microphone unit that outputs a signal to the amplitude / phase compensating means are combined into one microphone unit. The hearing aid according to claim 1. 3. A first microphone unit, a hearing aid signal amplifying means for extracting and amplifying a signal component of a predetermined frequency band from a signal supplied from the first microphone unit, a speaker unit, and the speaker. A second microphone arranged in the vicinity of the unit; and feedback circuit means for negatively feeding back the output of the second microphone to the output of the hearing aid signal amplifying means and supplying the feedback to the speaker unit. A hearing aid characterized by comprising a hearing aid consisting of 4. The hearing aid according to claim 1, wherein the hearing aid comprises two systems corresponding to the left and right ears.