JP4143832B2 - External sound perception device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an external sound perception apparatus for perceiving external sound by ultrasonic vibration.
[0002]
[Prior art]
Hearing aids for the hearing impaired are known as external sound perception devices for perceiving external sounds. Hearing aids include air-conducting hearing aids in which sound vibration is transmitted to the auditory organ of the brain through the eardrum, and bone-conducting hearing aids in which sound vibration is transmitted directly from the skull to the human body without going through the eardrum. Yes, the vibrator is used by attaching it to a predetermined part of the human body.
[0003]
Recently, a configuration is also known in which external sound can be perceived by transmitting ultrasonic vibrations to the auditory organ of the brain via a vibrator (Patent Documents 1 and 2). In Patent Document 2, an ultrasonic signal output from one modulation unit is configured to be input to a plurality of ultrasonic transducers connected in series or in parallel, and the plurality of ultrasonic transducers are It is shown that it is arranged at a predetermined part of the head.
[0004]
[Patent Document 1]
Japanese Unexamined Patent Publication No. 2001-320799 (first page, FIG. 9)
[0005]
[Patent Document 2]
Japanese Patent Laid-Open No. 2002-300700 (pages 1, 5 and 6 to 10)
[0006]
[Problems to be solved by the invention]
When multiple ultrasonic transducers are used, the sound sensing state (perceived state of external sound) can be made better than when a single ultrasonic transducer is used. The sensory state changes. For this reason, in the past, each vibrator was gradually moved while determining the sound sensing state to determine the mounting position. However, with this method, it is difficult to finely adjust the sound sensing state. It took time to install the child in the optimal position.
[0007]
The present invention has been made in view of these points, and an object of the present invention is to provide an external sound perception device that can easily and quickly optimize a sound sensing state.
[0008]
[Means for Solving the Problems]
The present inventors investigated the sound pressure distribution in the head when using a plurality of transducers, as will be described later, by performing actual measurement and numerical simulation using the head model. As a result, in the case of ultrasonic stimulation, it became clear that the sound pressure distribution in the living body is more complex than that of the audible sound stimulation, and the sound pressure distribution varies greatly depending on the attachment position of each transducer. The present inventors have obtained the following knowledge by analyzing the sound pressure distribution in the head under various conditions.
[0009]
That is, the object of the present invention is an external sound perception device for perceiving an external sound by ultrasonic vibration, a sound signal generating means for generating a sound signal based on the input external sound, and the sound signal A vibration signal generating unit that generates a vibration signal by modulating a carrier signal based on the vibration signal, and a vibration transmission unit that transmits ultrasonic vibration to the living body based on the vibration signal. A plurality of vibrators that can be fixed in contact with the predetermined position, and the vibration signal generating means includes an input unit capable of adjusting a phase of the carrier signal corresponding to at least one of the vibrators. And an external sound perception device configured to generate different vibration signals for each of the vibrators.
[0010]
In this external sound perception apparatus, it is preferable that the input unit is capable of adjusting the frequency and phase of the carrier signal corresponding to at least one of the vibrators.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, actual forms of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a front view showing a schematic configuration of an external sound perception apparatus according to an embodiment of the present invention, and FIG. 2 is a block diagram thereof. As shown in FIGS. 1 and 2, the external sound perception apparatus generates a sound signal based on an input external sound, and generates a vibration signal based on the obtained sound signal. A vibration signal generation unit 20 and a vibration transmission unit 30 that transmits mechanical vibration based on the vibration signal are provided.
[0012]
The sound signal generation unit 10 includes a microphone or the like, and generates a sound signal by detecting and amplifying sound from the outside.
[0013]
The vibration signal generation unit 20 includes a carrier signal generation unit 22 that generates a carrier signal, an input unit 24 that can adjust the frequency, amplitude, and timing (phase) of the carrier signal, and the sound signal generated by the sound signal generation unit 10. And a carrier signal modulation unit 26 that generates a vibration signal by modulating the carrier signal based on the above. The frequency of the carrier signal is preferably from 20 to 100 kHz, more preferably from 20 to 50 kHz, so as to obtain a good sound sensing state even for a highly deaf person. Therefore, it is preferable that the input unit 24 can adjust the frequency of the carrier signal in a range including a part or all of the frequency range. For example, the input unit 24 can be configured by individually adjustable volume switches so that the frequency, amplitude, and phase can be continuously changed.
[0014]
The vibration transmission unit 30 includes a plurality of vibrators that transmit vibration signals to the outside as mechanical vibrations. As shown in FIG. 3, the vibration transmitting unit 30 includes a plurality of cylindrical cases 32 in which the vibrators 31 are accommodated, and a suction cup 34 is attached to the opening edge of each case 32. Each case 32 may be coupled by a flexible connecting member or the like.
[0015]
The vibrator 31 is supported by a gimbal mechanism so as to be swingable about two axes orthogonal to each other. That is, the vibrator 31 is fixed to the first frame body 40 so that the vibration surface is exposed, and the first frame body 40 is attached to the second frame body 44 via the first support shaft 42. It is swingably supported. The second frame body 44 is swingably supported inside the case 32 via a second support shaft 46 orthogonal to the first support shaft 42. The vibration surface of the vibrator 31 protrudes slightly from the opening of the case 32. When the suction cup 34 is attracted to a predetermined attachment site, the vibration surface of the vibrator 31 is in contact with and pressed against the attracted surface. Has been. A communication hole 32a is formed at the center of the bottom (upper part of the figure) of each case 32, and a spherical bag-like body 48 is coupled to the communication hole 32a. The bag-like body 48 is made of an elastic material such as a rubber material, and is configured to be elastically deformable by pressing. The internal space of the bag 48 communicates with the inside of the case 32 through the communication hole 32a.
[0016]
In the external sound perception apparatus having the above-described configuration, a plurality of vibration signal generation units 20 are provided corresponding to the plurality of transducers 31, and vibration signals based on different carrier signals are provided to the respective transducers 31. It is configured to output.
[0017]
Next, the operation of the external sound perception apparatus will be described. First, the plurality of vibrators 31 are respectively attached to predetermined parts of the human body (for example, in the vicinity of milky protrusions). Each vibrator 31 can be reliably brought into contact with the human body by the gimbal mechanism by pressing the suction cup 34 against a predetermined portion while the bag-like body 48 is picked by hand. Thereafter, when the hand that has been picked is released, the inside of the case 32 becomes a negative pressure due to the shape restoring force of the bag-like body 48 and an adsorption force is obtained, so the attachment of the vibrator 31 can be ensured.
[0018]
After that, when an external sound is input by turning on the switch of the external sound perception device, the sound signal generation unit 10 converts the external sound into an electric signal to generate a sound signal, and amplifies it to a predetermined level. Later, the signal is output toward the vibration signal generator 20.
[0019]
In the vibration signal generation unit 20, the carrier signal generation unit 22 generates a carrier signal having a predetermined amplitude and frequency, and the carrier signal modulation unit 26 modulates the carrier signal based on the sound signal. Is generated. The vibration signal generation unit 20 individually generates a vibration signal corresponding to each vibrator 31 and outputs the vibration signal to the vibration transmission unit 30. The vibration transmitting unit 30 vibrates each vibrator 31 based on the inputted vibration signal. As a result, ultrasonic vibration corresponding to the external sound is transmitted to the human body. The carrier signal modulation unit 26 performs control so as not to output a vibration signal during a period in which no sound signal is input.
[0020]
A sound pressure distribution is generated in the head by the ultrasonic vibration from the vibration transmitting unit 30. In the present embodiment, the above-described configuration of the vibration transmitting unit 30 can effectively prevent positional displacement of the transducer 31 over time, but the sound pressure distribution in the head is determined by the mounting position of each transducer 31. Therefore, it is difficult to accurately attach each vibrator 31 to a portion where the sound sensing state is optimal. Therefore, in the present embodiment, the frequency, phase and amplitude of the carrier signal corresponding to each transducer 31 are configured to be individually adjustable at the input unit 24, and the frequency, phase and amplitude corresponding to any transducer 31 are configured. By gradually changing one of the amplitudes, the sound pressure distribution in the head can be finely adjusted. As a result, it is possible to control the position of the abdomen and nodes caused by the interference of ultrasonic waves, or to focus the ultrasonic waves and increase the sound pressure locally, so that the sound sensing state can be optimized easily and quickly. Can be
[0021]
Although the specific method for optimizing a sound-sensitive state is not specifically limited, For example, the following method can be mentioned. First, the amplitude of the ultrasonic waves emitted from the plurality of vibrations 31 is set to be small, and each of the vibrators 31 is positioned by appropriately attaching to each mastoid so that the sound-sensing state is generally good. I do. Then, the frequency and phase of each transducer 31 are adjusted and determined so that the sound sensing state becomes better. For example, when two vibrators 31 are attached and used, the frequency of the carrier signal corresponding to each vibrator 31 is simultaneously changed to set the frequency at which the sound sensing state is the best. Thereafter, by setting the phase of the carrier signal corresponding to each vibrator 31 in the same manner, the optimum frequency and phase of the carrier signal can be obtained individually for each vibrator 31, and the sound sensing state Can be optimized. Either the frequency or phase may be set first. Finally, the amplitude is set to a desired magnitude so that a desired sound sensing state can be obtained.
[0022]
As another method for optimizing the sound sensing state, the carrier signal corresponding to the other transducer 31 while maintaining the frequency, phase and amplitude of the carrier signal corresponding to one transducer 31 at predetermined values. It is also possible to optimize the sound sensing state by sequentially changing the frequency, phase and amplitude. In this case, it is only necessary that the input unit 24 can adjust the frequency, phase, and amplitude of the carrier signal corresponding to at least one transducer 31.
[0023]
【Example】
Using the time-domain finite difference method (FDTD method) used for analysis of sound fields in fluids, the sound field formed in the head by the transducer is obtained by calculation. The change of the sound pressure distribution due to the difference in the frequency and phase of the carrier signal corresponding to the.
[0024]
Specifically, first, a human head model is created with reference to a standard Japanese male head anatomy, and a plurality of circular diaphragms having a radius of 5 mm are arranged near the left ear of the head model. The bone conduction sound presentation was simulated as that it vibrates uniformly. A cross-sectional view of the xy plane head model including the cochlea is shown in FIG. In FIG. 4, “I”, “II”, and “III” indicate attachment positions of the transducer I, the transducer II, and the transducer III, respectively. “I” is in front of the ear and “II” is in the ear. Back, “III” is behind the ear. The excitation waveform applied to the sound source was a continuous sine wave obtained by multiplying the rising wave by a ramp function. As an example, an excitation waveform of 30 kHz is shown in FIG.
[0025]
(Condition 1) Change in sound pressure distribution due to frequency difference Using the vibrator I and the vibrator II in the head model, changing the frequency of the vibrator II while maintaining the frequency of the vibrator I at 30 kHz, The sound pressure distribution in the head was examined.
The phases of the vibrator I and the vibrator II were set to be the same (phase difference 0). 5 and 6 show the sound pressure distribution in the head cross section shown in FIG. 4 in shades, and the unit of the vertical axis and the horizontal axis is mm. FIGS. 5A to 5D correspond to cases where the frequency of the vibrator II is 15 kHz, 20 kHz, 30 kHz, and 30.001 kHz, respectively, and FIGS. 6A to 6D are diagrams of the vibrator II. This corresponds to the case where the frequencies are 30.01 kHz, 30.1 kHz, 31 kHz, and 32 kHz, respectively. 7 and 8 show changes in sound pressure (vertical axis) over time (horizontal axis) in the left cochlea under frequency conditions corresponding to FIGS. 5 and 6, respectively.
[0026]
As apparent from FIGS. 5 to 8, by gradually changing the excitation frequency of the vibrator, the sound pressure distribution in the head and the sound sensitivity level at a predetermined portion also change gradually. In this way, the sound sensing state can be controlled by adjusting the frequency of the carrier signal corresponding to one of the vibrators.
[0027]
(Condition 2) Change in sound pressure distribution due to phase difference In the above head model, vibrator I and vibrator II are used, and vibrator I and vibrator II are vibrated with the frequency of vibrator I and vibrator II maintained at 30 kHz. A phase difference with child II was generated, and the sound pressure distribution in the head was examined. 9 to 12 show the sound pressure distribution in the cross section shown in FIG. 4 in shades, and the unit of the vertical axis and the horizontal axis is mm. 9A to 9C correspond to cases where the phase delay of the vibrator II with respect to the phase of the vibrator I is 180 °, 150 °, and 120 °, respectively. (C) corresponds to the case where the phase delay of the vibrator II with respect to the phase of the vibrator I is 90 °, 60 °, and 30 °, respectively. 11 (a) to 11 (c) correspond to cases where the phase advance of the vibrator II with respect to the phase of the vibrator I is 180 °, 150 °, and 120 °, respectively. ) To (c) correspond to cases where the phase advance of the vibrator II with respect to the phase of the vibrator I is 90 °, 60 ° and 30 °, respectively. Moreover, FIGS. 13-16 has shown the time (horizontal axis) change of the sound pressure (vertical axis) in the left cochlea under the frequency conditions corresponding to FIGS. 9-12, respectively.
[0028]
As is apparent from FIGS. 9 to 16, by gradually changing the phase difference between the excitation waveforms in the plurality of vibrators, the sound pressure distribution in the head and the sound sensitivity level at the predetermined portion also change gradually. In this way, the sound sensing state can be controlled by adjusting the phase of the carrier signal corresponding to one of the vibrators.
[0029]
(Condition 3) Change in sound pressure distribution due to difference in mounting position In the above head model, the combination of two or more vibrators used from three vibrators (vibrator I, vibrator II and vibrator III) is changed. The sound pressure distribution in the head was examined. FIG. 17 shows the sound pressure distribution in the cross section shown in FIG. 4 in shades, and the unit of the vertical axis and the horizontal axis is mm. 17A to 17D correspond to the combinations of the vibrators I and II, the vibrators II and III, the vibrators I and III, and the vibrators I, II, and III. FIG. 18 shows the time (horizontal axis) change of the sound pressure (vertical axis) in the left cochlea under each condition corresponding to FIG. The frequency of each vibrator was 30 kHz and the phase difference was zero.
[0030]
As apparent from FIGS. 17 and 18, the sound pressure distribution and the sound pressure level at a predetermined portion are greatly changed only by slightly different attachment positions of the vibrators. Thus, it is difficult to optimize the sound sensing state by changing the attachment position of the vibrator.
[0031]
(Condition 4) Sound pressure distribution by audible sound In the above condition 3, the sound pressure distribution in the head was examined under the same conditions except that the frequency of each transducer was 3 kHz. 19A to 19D correspond to the combinations of the vibrators I and II, the vibrators II and III, the vibrators I and III, and the vibrators I, II, and III. FIG. 20 shows the time (horizontal axis) change of the sound pressure (vertical axis) in the left cochlea under each condition corresponding to FIG.
[0032]
As is apparent from FIGS. 19 and 20, even if the attachment position of the vibrator changes, the sound pressure distribution and the sound pressure level at the predetermined portion hardly change. Thus, in the case of audible sound, the influence of the attachment position of the vibrator on the sound sensing state is small.
[0033]
【The invention's effect】
As is clear from the above description, according to the present invention, it is possible to provide an external sound perception device that can easily and quickly optimize a sound sensing state.
[Brief description of the drawings]
FIG. 1 is a front view showing a schematic configuration of an external sound perception device according to an embodiment of the present invention.
FIG. 2 is a block diagram of the external sound perception device.
FIG. 3 is a cross-sectional view of a vibration transmission unit in the external sound perception device.
FIGS. 4A and 4B are diagrams showing (a) a head model and (b) an excitation waveform used for analyzing a sound pressure distribution in the head of a human body.
FIG. 5 is a diagram illustrating an example of an analysis result of a sound pressure distribution in the head.
FIG. 6 is a diagram illustrating another example of the analysis result of the intra-head sound pressure distribution.
FIG. 7 is a diagram showing a temporal change in sound pressure at a predetermined portion corresponding to FIG.
FIG. 8 is a diagram showing a temporal change in sound pressure at a predetermined portion corresponding to FIG.
FIG. 9 is a diagram showing an example of the analysis result of the intra-head sound pressure distribution.
FIG. 10 is a diagram illustrating another example of the analysis result of the intra-head sound pressure distribution.
FIG. 11 is a diagram showing still another example of the analysis result of the sound pressure distribution in the head.
FIG. 12 is a diagram showing still another example of the analysis result of the sound pressure distribution in the head.
13 is a diagram showing a temporal change in sound pressure at a predetermined portion corresponding to FIG. 9. FIG.
FIG. 14 is a diagram showing a temporal change in sound pressure at a predetermined portion corresponding to FIG.
FIG. 15 is a diagram showing a temporal change in sound pressure at a predetermined portion corresponding to FIG.
FIG. 16 is a diagram showing a temporal change in sound pressure at a predetermined portion corresponding to FIG.
FIG. 17 is a diagram showing an example of the analysis result of the intra-head sound pressure distribution.
FIG. 18 is a diagram showing a temporal change in sound pressure at a predetermined portion corresponding to FIG.
FIG. 19 is a diagram showing an example of the analysis result of the intra-head sound pressure distribution.
20 is a diagram showing a temporal change in sound pressure at a predetermined portion corresponding to FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Sound signal generation part 20 Vibration signal generation part 22 Carrier signal generation part 24 Input part 26 Carrier signal modulation part 30 Vibration transmission part 31 Vibrator 32 Case 34 Suction cup

Claims (2)

An external sound perception device for perceiving external sound by ultrasonic vibration,
Sound signal generating means for generating a sound signal based on the input external sound;
Vibration signal generating means for generating a vibration signal by modulating a carrier signal based on the sound signal;
Vibration transmitting means for transmitting ultrasonic vibration to the living body based on the vibration signal,
The vibration transmission means includes a plurality of vibrators that can be fixed in contact with a predetermined position of a living body,
The vibration signal generating means includes an input unit capable of adjusting the phase of the carrier signal corresponding to at least one of the vibrators, and is configured to generate the different vibration signals for each vibrator. Perceptual device. The external sound perception apparatus according to claim 1, wherein the input unit is capable of adjusting a frequency and a phase of the carrier signal corresponding to at least one of the vibrators.

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