Hearing ability auxiliary device

Abstract

To provide a hearing ability auxiliary device capable of suppressing discomfort due to a howl with a simple constitution.SOLUTION: A filter part 15 of a hearing capability auxiliary device 10 preferentially passes a howling component of an audio signal input from a microphone part 11. A detection part 16 detects a level of the howling component. A waveform formation part 17 differentiates a rise part of a detection output voltage that the detection part 16 outputs so as to generate a trigger pulse indicating that a howl is generated. A hold part 18 generates a predetermined-period hold signal on the basis of, the trigger pulse. A muting part 13 is interposed between the microphone part 11 and an earphone part 14, and blocks transmission of the audio signal from the microphone part 11 to the earphone part 14 for a certain time on the basis of the hold signal output from the howl detection part 12.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a hearing aid device, and more particularly to a hearing aid device that can suppress discomfort caused by feedback. [Background technology]

[0002] In recent years, digital hearing aids and sound amplifiers for the hearing impaired have become increasingly popular, and many models boast feedback cancellation.

[0003] Feedback is an oscillating sound that occurs when the microphone sound is amplified and the sound emitted from the earphone speaker is reflected and returned to the microphone, creating a feedback loop that causes the loop's specific frequency signal to be amplified infinitely up to the dynamic range of the circuit. Feedback occurs in hearing aids and sound amplifiers because when the earphone is brought close to the ear, the sound emitted from the earphone speaker is reflected off the auricle, creating a loop that feeds back to the nearby microphone. This is a very harsh sound, and feedback suppression performance is an important factor in determining the performance of a hearing aid or sound amplifier.

[0004] While expensive hearing aids effectively suppress feedback, many inexpensive hearing aids and sound amplifiers, even if they claim to suppress feedback, often malfunction or do not fully cancel feedback, resulting in unsatisfactory feedback cancellation performance.

[0005] Patent Document 1 describes an invention relating to a hearing aid that suppresses feedback components. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-57873 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the howling suppression technology according to the background art described above has room for improvement in terms of suppressing the discomfort caused by howling.

[0008] Specifically, the feedback suppression technology widely used in digital hearing aids and sound amplifiers according to the background art described above is a feedback cancellation method, which synthesizes a signal generated at the same frequency and level as the feedback in reverse phase to cancel the feedback. However, the challenge is how accurately a signal that cancels an unstable feedback signal can be instantaneously generated. Digital signal processing requires a finite amount of time, making it extremely difficult to adaptively generate an unstable feedback signal. Therefore, if the feedback component cannot be tracked and canceled, there are problems such as the feedback remaining or distortion or noise being generated. Furthermore, the characteristic elements required to track unstable feedback are not simple, making it difficult to distinguish between feedback that changes both in level and frequency and sound in the same frequency band.

[0009] The present invention has been made in view of the above problems, and has as its object to provide a hearing aid device that can suppress the discomfort caused by feedback with a simple configuration. [Means for solving the problem]

[0010] The present invention is a hearing assistance device that amplifies and outputs sound collected from the outside, and is equipped with a hold unit that generates a hold signal for a predetermined period of time, and a mute unit that, when feedback occurs, stops the output based on the hold signal and blocks the transmission of audio signals from the microphone unit to the earphone unit for a certain period of time, and is characterized in that the hold unit includes a monostable multi-circuit. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a hearing aid device that can suppress discomfort caused by feedback with a simple configuration. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a block diagram of a hearing aid device according to an embodiment of the present invention. [Figure 2] 1 is a diagram showing a situation in which a hearing aid according to an embodiment of the present invention is worn; [Figure 3] 4 is a graph showing the function of a filter unit in a hearing assistance device according to an embodiment of the present invention. [Figure 4] FIG. 2 is a diagram illustrating the function of a detection unit in a hearing assistance device according to an embodiment of the present invention. [Figure 5] FIG. 2 is a diagram showing the functions of a detection section and a waveform shaping section in a hearing assistance device according to an embodiment of the present invention. [Figure 6] 10 is a diagram showing the function of a holding section in a hearing assistance device according to an embodiment of the present invention. FIG. [Figure 7A] FIG. 2 is a diagram illustrating the function of a mute unit in a hearing assistance device according to an embodiment of the present invention. [Figure 7B] 10 is a graph showing the effect of a mute unit in a hearing assistance device according to an embodiment of the present invention. [Figure 8] 10 is a graph showing the effect of a hearing assistance device according to an embodiment of the present invention. [Figure 9] 10 is a graph showing howling that occurs in a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0013] A hearing assistance device 10 according to an embodiment of the present invention will now be described in detail with reference to the drawings. In the following description, the same components will generally be given the same reference numerals, and repeated description will be omitted.

[0014] FIG. 1 is a block diagram of a hearing aid device 10.

[0015] Hearing assistance device 10 is a device that amplifies and outputs sound collected from an external source, and includes a mute unit 13 that stops output for a certain period of time when feedback occurs. Specifically, hearing assistance device 10 mainly includes a microphone unit 11, a feedback detection unit 12, a mute unit 13, and an earphone unit 14. Hearing assistance device 10 is used to assist the hearing function of elderly people with weakened hearing, and is sometimes referred to as a hearing aid or sound collector, for example.

[0016] To explain the specific connection configuration of hearing assistance device 10, microphone unit 11, preamplifier 19, buffer 20, mute unit 13, volume 21, power amplifier 22, and earphone unit 14 are connected in series. The input terminal of feedback detection unit 12 is connected to the midpoint between preamplifier 19 and buffer 20. The output terminal of feedback detection unit 12 is connected to mute unit 13. In this embodiment, the loop in which sound output from earphone unit 14 is fed back to microphone unit 11 is called a feedback loop.

[0017] The howling detection unit 12 has a filter unit 15, a detection unit 16, a waveform shaping unit 17, and a hold unit 18. The filter unit 15, the detection unit 16, the waveform shaping unit 17, and the hold unit 18 are connected in series.

[0018] Here, the function of each part of the hearing aid device 10 will be briefly described.

[0019] The microphone unit 11 generates an audio signal based on the volume of an externally input sound.

[0020] The preamplifier 19 amplifies the audio signal input from the microphone unit 11 .

[0021] The buffer 20 is, for example, an amplifier or a resistor, and has the function of reducing the effect of the output load from being fed back to the input.

[0022] The filter unit 15 preferentially passes feedback components of the audio signal input from the microphone unit 11.

[0023] The detector 16 detects the level of the howling component.

[0024] The waveform shaping section 17 differentiates the rising edge of the detected output voltage output by the detection section 16 to generate a trigger pulse indicating the occurrence of howling.

[0025] The hold section 18 generates a hold signal for a predetermined period based on the trigger pulse.

[0026] Mute unit 13 is interposed between microphone unit 11 and earphone unit 14, and blocks the transmission of audio signals from microphone unit 11 to earphone unit 14 for a certain period of time based on a hold signal output from feedback detection unit 12. Mute unit 13 can be placed anywhere between preamplifier 19 and earphone unit 14.

[0027] The volume 21 is, for example, a variable resistor, and adjusts the volume of the sound output in response to a user operation.

[0028] The power amplifier 22 amplifies the input audio signal in accordance with the setting of the volume 21 .

[0029] The earphone unit 14 generates a predetermined sound based on the audio signal input from the power amplifier 22 .

[0030] To explain the basic function of the hearing assistance device 10, sound input to the microphone unit 11 is converted into sound voltage, passes through the preamplifier 19, buffer 20, and volume 21, is power amplified by the power amplifier 22, and is then converted into sound by the earphone unit 14 (earphone) and output as sound pressure.

[0031] Meanwhile, in feedback detection unit 12, filter unit 15 extracts a feedback signal based on the audio signal input from preamplifier 19, and detection unit 16 detects the feedback signal to detect the occurrence of feedback. Then, hold unit 18 holds the detected output for a fixed period of time, and the held output turns off mute unit 13 for a fixed period of time to eliminate feedback. By doing this, the device is muted during that period, and no feedback sound is output from earphone unit 14 during the muted period.

[0032] 2 is a diagram showing a state in which the hearing aid device 10 is worn. The wearing unit 26 that constitutes the hearing aid device 10 includes an earpiece 27, an earphone unit 14, and a microphone unit 11.

[0033] When the user attempts to insert the attachment part 26 into the ear canal 28, as described above, the sound emitted from the earphone part 14 and the earpiece 27 is reflected by the auricle 25 and returns to the nearby microphone part 11, creating a loop that may result in howling.

[0034] In this embodiment, when feedback is detected, the hearing assistance device 10 is configured as described above to mute the output for a certain period of time. Therefore, even if feedback occurs when the user tries to wear the hearing assistance device 10, the feedback sound can be prevented from being continuously generated, and the discomfort caused by the feedback can be reduced.

[0035] The functions of each component of the hearing aid device 10 will now be described in detail with reference to FIG. 3 and subsequent figures.

[0036] Fig. 3 is a graph showing the function of filter unit 15, which preferentially passes feedback components. In the graph of Fig. 3, the vertical axis represents the magnitude of the audio signal input to filter unit 15, and the horizontal axis represents the frequency.

[0037] When the hearing aid 10 extracts a feedback signal, the feedback suppression function may malfunction due to the influence of sound. Therefore, the filter unit 15 attenuates the audio band to distinguish between feedback and sound. The filter unit 15 is a high-pass filter that barely attenuates frequency components higher than the cutoff frequency of the audio band, but attenuates frequency components lower than the cutoff frequency. The audio frequency band is approximately 100 Hz to 2 kHz, and hearing aid feedback frequencies occur in the range of 2 kHz to 5 kHz. Therefore, audio signals in the audio band are attenuated by the filter unit 15. Specifically, the filter unit 15 has a cutoff frequency of 2 kHz, and attenuates the audio band from 100 Hz to 500 Hz by approximately 20 dB. This widens the level difference between feedback and audio signals, allowing for the extraction of feedback signals with minimal audio influence. Furthermore, it is possible to prevent feedback signal detection malfunctions due to sounds such as shouting. Here, the audio signal before attenuation by the filter unit 15 is indicated by a broken line, and the audio signal after attenuation is indicated by a dashed line.

[0038] Fig. 4 is a diagram showing the function of the detection unit 16 that detects the level of the howling component, showing the howling signal, the audio signal, the bias voltage, and the detected output waveform.

[0039] When detecting the howling signal level, the detector 16 sets the detection level between the audio level and the howling level to eliminate the influence of the audio. Specifically, the detector 16 has a bias circuit of Vb, blocks audio signals below Vb, and detects (passes) howling signals above Vb.

[0040] Fig. 5 is a diagram showing the functions of the detector 16 and the waveform shaping section 17. Fig. 5 shows a feedback signal, the detector 16, the waveform after detection, the waveform shaping section 17, and a trigger pulse.

[0041] The detection unit 16 detects the input howling signal to detect the occurrence of howling, and more specifically, detects the level of the howling component. The detection unit 16 outputs a detected waveform whose level has been detected.

[0042] The waveform shaping unit 17 has a capacitor and a resistor. The capacitor is inserted in the connection line connecting the detection unit 16, the waveform shaping unit 17, and the hold unit 18. The resistor is inserted between the connection line and ground. The waveform shaping unit 17 differentiates the rising edge of the detection output voltage output by the detection unit 16 to generate a trigger pulse indicating the occurrence of feedback.

[0043] 6 is a diagram showing the function of the hold unit 18 that generates a hold signal for a predetermined period based on a trigger pulse, showing the trigger pulse, the hold unit 18, and the pulse that is generated.

[0044] The hold unit 18 is composed of, for example, a monostable multi-circuit. When a trigger pulse is input to the hold unit 18, the hold unit 18 generates a hold signal, which is a pulse for setting the time to disconnect the feedback loop. The time T of the hold signal is the time required for the user to insert the attachment unit 26 into the ear canal 28, and is, for example, 800 msec. The upper limit of the hold signal time T is preferably 1000 msec, more preferably 900 msec, and particularly preferably 850 msec. On the other hand, the lower limit of the hold signal time T is preferably 600 msec, more preferably 700 msec, and particularly preferably 750 msec. By setting the hold signal time T within this range, feedback noise generated when the user wears the attachment unit 26 can be effectively blocked, thereby reducing the discomfort caused by the feedback noise.

[0045] 7A is a diagram showing the function of the mute unit 13. Here, the mute unit 13 has a transistor 23. The transistor 23 is disposed between the buffer 20 and the power amplifier 22, and its control electrode is connected to the howling detection unit 12.

[0046] Therefore, when the aforementioned hold unit 18 included in the feedback detection unit 12 applies a hold signal to the control electrode of the transistor 23, the transistor 23 is turned off. As a result, the audio signal that has passed through the preamplifier 19, capacitor 24, and buffer 20 does not reach the power amplifier 22. In other words, based on the hold signal output from the feedback detection unit 12, transmission of the audio signal from the microphone unit 11 to the earphone unit 14 is blocked for a certain period of time.

[0047] FIG. 7B is a graph showing the function of the mute unit 13, with the horizontal axis representing time and the vertical axis representing sound volume.

[0048] Referring to this graph, the period up to time T1 is the period during which the user is about to insert the attachment unit 26 into the ear canal 28. The period from time T1 to time T2 is the period after the attachment unit 26 has been completely inserted into the ear canal 28. In this embodiment, howling that occurs particularly in the period up to time T1 is muted, thereby reducing the discomfort that the muting causes to the user.

[0049] If feedback is detected at time T3, the hearing aid device 10 cuts off audio signal transmission using the transistor 23 of the mute unit 13. As a result, no audio signal is transmitted to the power amplifier 22, and no continuous feedback noise is generated from the earphone unit 14. The transistor 23 continues to cut off audio signal transmission for the time from time T3 to time T4, for example, 800 msec. This prevents feedback noise from being generated from the earphone unit 14, thereby reducing discomfort to the user. Although some feedback noise is generated from the earphone unit 14 before feedback is detected, the duration of the feedback noise is very short, for example, about 30 msec, and amounts to a slight beep, so the discomfort to the user is considered minimal.

[0050] Thereafter, the mute section 13 transmits the audio signal at time T4. Therefore, for a period of time after time T4, the feedback loop is connected, creating an environment in which feedback can grow.

[0051] If the howling grows again at time T5, the mute unit 13 again blocks the transmission of the audio signal until time T6, stopping the howling sound from being generated from the earphone unit 14 and suppressing the user's discomfort.

[0052] That is, in this embodiment, even if howling occurs multiple times while the user is wearing the attachment unit 26 on their ear, the occurrence of howling can be stopped by cutting off the transmission of the audio signal each time, thereby suppressing the user's discomfort.

[0053] 8 is a graph showing the effect of the hearing aid device 10. In this graph, the horizontal axis represents time, and the vertical axis represents the volume of sound output from the earphone unit 14 of the hearing aid device 10.

[0054] As shown in Fig. 2, when a user tries to attach the attachment part 26 to the ear canal 28, howling occurs as sound reverberates from the pinna 25. In the graph of Fig. 8, howling occurs multiple times just before the attachment part is inserted.

[0055] As described above, in this embodiment, when feedback detection unit 12 detects feedback, mute unit 13 temporarily blocks audio output to earphone unit 14. This prevents feedback sound from being continuously output from earphone unit 14.

[0056] However, it is also conceivable that the user may insert the attachment unit 26 into the ear canal 28 immediately before inserting the attachment unit. In this case, as described above, the sound heard by the user before feedback detection is short, on the order of several tens of milliseconds, and is therefore a light, unnoticeable "beep" sound. Furthermore, if the attachment unit 26 is not being worn and feedback is occurring, feedback will grow again, and detection and audio muting will be repeated, resulting in a repeated "beep, beep" detection sound. This detection sound is far less unpleasant to the user than the high-pitched "beep, beep" sound that is the feedback sound.

[0057] Furthermore, after the user wears the attachment unit 26, the hearing assistance device 10 performs its original function, amplifying the audio signal input from the microphone unit 11, and sound based on the amplified audio signal is generated from the earphone unit 14.

[0058] 9 is a graph showing howling that occurs in a comparative example that does not have the mute function of the present invention. In this graph, the horizontal axis represents time, and the vertical axis represents the volume of sound output from earphone unit 14 of hearing assistance device 10.

[0059] In the comparative example, a continuous howling noise occurs immediately before the attachment part is inserted. Therefore, the user experiences significant discomfort as he or she continues to hear the high-pitched howling noise generated from the earphone part 14. The howling noise is particularly irritating near the ear canal 28, causing significant discomfort to the user.

[0060] On the other hand, in this embodiment, as described above, the howling loop is cut off for a certain period of time to stop the howling oscillation, and during that time the attachment part 26 is inserted into the ear canal 28, so that the attachment part 26 can be worn without hearing any unpleasant howling.

[0061] Although the embodiments of the present invention have been described above, the present invention is not limited to these and can be modified within the scope of the present invention. In addition, the above-described embodiments can be combined with each other.

[0062] This embodiment provides a satisfactory feedback suppression technology that uses a muting method rather than a cancellation method in inexpensive analog hearing aids and sound collectors. Because this embodiment is a fundamental elemental technology for feedback suppression, the feedback suppression function can be realized not only by analog circuits but also by digital signal processing using DSP.

[0063] Furthermore, this embodiment has two attachment parts 26, one for the right ear and one for the left ear, and it is possible to configure a separate hearing assistance device 10 for each attachment part 26. In this way, it is possible to individually suppress the howling noise that occurs when the attachment parts 26 are inserted into the left and right ears.

[0064] The invention that can be understood from the above-described embodiment will be described below together with its effects.

[0065] The hearing aid device of the present invention amplifies and outputs sounds collected from an external source, and is characterized by having a mute unit that stops the output for a certain period of time when feedback occurs. Therefore, according to the hearing aid device of the present invention, by executing muting to stop the output for a certain period of time when feedback is detected, even if feedback occurs when the user wears the hearing aid device in their ear, the howling sound will not be generated continuously, and the discomfort caused by the feedback can be reduced.

[0066] Furthermore, the hearing assistance device of the present invention is a hearing assistance device that amplifies and outputs sound collected from the outside, and is equipped with a microphone unit, a feedback detection unit, a mute unit, and an earphone unit, and the feedback detection unit has a filter unit, a detection unit, a waveform shaping unit, and a hold unit, and the filter unit preferentially passes feedback components of the audio signal input from the microphone unit, the detection unit detects the level of the feedback components, the waveform shaping unit generates a trigger pulse indicating the occurrence of feedback by differentiating the rising portion of the detected output voltage output by the detection unit, the hold unit generates a hold signal for a predetermined period based on the trigger pulse, and the mute unit is interposed between the microphone unit and the earphone unit, and blocks the transmission of the audio signal from the microphone unit to the earphone unit for a certain period of time based on the hold signal output from the feedback detection unit. Therefore, with the hearing assistance device of the present invention, the transmission of audio signals from the microphone unit to the earphone unit is blocked for a certain period of time only when the howling detection unit detects howling, thereby suppressing the continuous generation of howling sounds when the device is worn and significantly reducing the discomfort experienced by the user.

[0067] Furthermore, in the hearing assistance device of the present invention, the filter section attenuates audio signals in the human voice band, thereby making it possible to prevent human voices from being mistaken for feedback noise.

[0068] In addition, in the hearing assistance device of the present invention, the mute unit cancels the blocking after the certain period of time has elapsed. Therefore, with the hearing assistance device of the present invention, output from the earphone unit is stopped only while feedback is occurring, and sound can be output from the earphone unit after the earphone is no longer being worn. [Explanation of symbols]

[0069] 10 Assistive hearing devices 11 Microphone section 12. Feedback detection section 13 Mute section 14 Earphone section 15 Filter section 16 Detector 17 Waveform shaping section 18 Hold section 19 Preamp 20 buffers 21 Volume 22 Power Amplifier 23 Transistor 24 capacitors 25 Auricle 26 Mounting part 27 earpieces 28 Ear canal

Claims

[Claim 1] It is a hearing aid that amplifies and outputs sounds collected from outside. a hold unit that generates a hold signal for a predetermined period; a mute unit that stops the output by interrupting transmission of an audio signal from the microphone unit to the earphone unit for a certain period of time based on the hold signal when feedback occurs, 10. A hearing aid device, wherein the holding section includes a monostable multi-circuit.

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