JP2004343302A - External sound perceiving apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an external sound perceiving apparatus which easily and quickly optimizes a sound sensing condition. <P>SOLUTION: The outside sound perceiving apparatus for perceiving outside sounds by ultrasonic vibrations comprises a means 10 for generating sound signals based on inputted outside sounds, a means 20 for generating vibration signals by modulating a carrier signal based on the sound signals, and a means 30 for transferring ultrasonic vibrations to a living body based on the vibration signals. The vibration transferring means 30 comprises a plurality of vibrators 31 fixable while being contacted to specified positions of the living body. The vibration signal generating means 20 is structured to make the vibrators 31 generate their respectively different vibration signals. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an external sound perception device for perceiving external sound by ultrasonic vibration.
[0002]
[Prior art]
BACKGROUND ART A hearing aid for a hearing-impaired person is known as an external sound perception device for perceiving external sound. Hearing aids include air-conducting hearing aids, in which sound vibrations are transmitted to the auditory organs of the brain via the eardrum, and bone conduction hearing aids, in which sound vibrations are transmitted directly to the human body from the skull, etc., without passing through the eardrum. Yes, a vibrator is attached to a predetermined part of the human body for use.
[0003]
Recently, there has been known a configuration in which an external sound can be perceived by transmitting ultrasonic vibration to a hearing organ of the brain via a vibrator (Patent Documents 1 and 2). Patent Literature 2 discloses a configuration in which an ultrasonic signal output from one modulation unit is input to a plurality of ultrasonic transducers connected in series or in parallel, respectively. It is shown to be located at a predetermined part of the head.
[0004]
[Patent Document 1]
JP-A-2001-320799 (page 1, FIG. 9)
[0005]
[Patent Document 2]
JP-A-2002-300700 (pages 1, 5; FIGS. 6 to 10)
[0006]
[Problems to be solved by the invention]
When a plurality of ultrasonic transducers are used, the sound-sensing state (perception state of external sound) can be made better than when a single ultrasonic transducer is used. The sound-sensing state changes according to this. For this reason, conventionally, the vibrator was gradually moved while determining the sound-sensing state to determine the mounting position. However, with such a method, it is difficult to fine-tune the sound-sensing state. It took time to attach the child to the optimal position.
[0007]
The present invention has been made in view of such a point, 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 examined the sound pressure distribution in the head when a plurality of transducers were used, as described later, by performing actual measurement and numerical simulation using a head model. As a result, it became clear that the sound pressure distribution in the living body was more complicated in the case of ultrasonic stimulation than in the case of audible sound stimulation, and the sound pressure distribution greatly changed depending on the mounting position of each transducer. The present inventors have obtained the following findings 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 generation unit that generates a vibration signal by modulating a carrier signal based on the vibration signal; anda vibration transmission unit that transmits ultrasonic vibrations to a living body based on the vibration signal. A plurality of vibrators that can be fixed in a state where the vibrator is in contact with a predetermined position, and wherein the vibration signal generating means is configured to generate the different vibration signals for each of the vibrators. Achieved by the device.
[0010]
In this external sound perception device, it is preferable that the vibration signal generation unit includes an input unit capable of adjusting a frequency and / or a phase of the carrier signal corresponding to at least one of the vibrators.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments 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 device 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 device generates a sound signal based on an input external sound and a vibration signal based on the obtained sound signal. The apparatus includes a vibration signal generation unit 20 and a vibration transmission unit 30 that transmits mechanical vibration based on the vibration signal.
[0012]
The sound signal generation unit 10 includes a microphone or the like, and generates a sound signal by detecting and amplifying external sound.
[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 a sound signal generated by the sound signal generation unit 10. And a carrier signal modulator 26 that generates a vibration signal by modulating the carrier signal based on the carrier signal. The frequency of the carrier signal is preferably 20 to 100 kHz, which is an ultrasonic range, and more preferably 20 to 50 kHz so that a good sound-sensing state can be obtained even for a highly deaf person. Therefore, it is preferable that the input unit 24 can adjust the frequency of the carrier signal within a range including a part or the whole of the frequency range. The input unit 24 can be configured by, for example, a volume switch that can be individually adjusted so that the frequency, the amplitude, and the phase can be continuously changed.
[0014]
The vibration transmitting unit 30 includes a plurality of vibrators that transmit a vibration signal to the outside as mechanical vibration. As shown in FIG. 3, the vibration transmitting unit 30 includes a plurality of cylindrical cases 32 in which the vibrators 31 are housed, and is configured by attaching suction cups 34 to the opening edges of each case 32. The cases 32 may be connected by a flexible connecting member or the like.
[0015]
The vibrator 31 is swingably supported by a gimbal mechanism about two axes orthogonal to each other. That is, the vibrator 31 is fixed to the first frame 40 so as to expose the vibrating surface, and the first frame 40 is attached to the second frame 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 vibrating surface of the vibrator 31 slightly protrudes from the opening of the case 32, and is configured so that when the suction cup 34 is attracted to a predetermined mounting portion, the vibrating surface of the vibrator 31 comes into contact with and is pressed against the surface to be attracted. Have been. A communication hole 32a is formed at the center of the bottom (upper part in the figure) of each case 32, and a spherical bag-like body 48 is connected 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-like body 48 communicates with the inside of the case 32 via the communication hole 32a.
[0016]
In the external sound perception device having the above configuration, a plurality of vibration signal generators 20 are provided corresponding to the plurality of vibrators 31, and each of the vibrators 31 outputs a vibration signal based on a different carrier signal. It is configured to be able to output.
[0017]
Next, the operation of the external sound perception device will be described. First, the plurality of transducers 31 are attached to predetermined portions of the human body (for example, near the mastoid). Each vibrator 31 can reliably contact the human body by the gimbal mechanism by pressing the suction cup 34 to a predetermined portion while the bag-like body 48 is picked up by hand. Thereafter, when the picked-up hand is released, the inside of the case 32 becomes a negative pressure due to the shape restoring force of the bag-shaped body 48 and the suction force is obtained, so that the vibrator 31 can be securely attached.
[0018]
Thereafter, when the switch of the external sound perception device is turned on and an external sound is input, the sound signal generation unit 10 converts the external sound into an electric signal to generate a sound signal, and amplifies the signal to a predetermined level. Later, it outputs to the vibration signal generation unit 20.
[0019]
The vibration signal generation unit 20 is configured such that 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 a sound signal, thereby generating a vibration signal. Generate 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 input vibration signal. As a result, the ultrasonic vibration corresponding to the external sound is transmitted to the human body. Note that the carrier signal modulator 26 controls so as not to output a vibration signal during a period when no sound signal is input.
[0020]
Due to the ultrasonic vibration from the vibration transmitting unit 30, a sound pressure distribution is generated in the head. In the present embodiment, the above-described configuration of the vibration transmission unit 30 can effectively prevent the positional displacement of the vibrator 31 over time, but the sound pressure distribution in the head depends on the mounting position of each vibrator 31. It is difficult to accurately attach each vibrator 31 to a position where the sound-sensing state is optimal because of a slight change due to a slight difference between the two. Thus, in the present embodiment, the frequency, phase and amplitude of the carrier signal corresponding to each transducer 31 are configured to be individually adjustable in the input unit 24, and the frequency, phase and amplitude corresponding to any transducer 31 are adjusted. By gradually changing any of the amplitudes, it is possible to finely adjust the sound pressure distribution in the head. As a result, it is possible to control the positions of the belly and nodes caused by the interference of the ultrasonic waves, and to locally increase the sound pressure by focusing the ultrasonic waves, and to easily and quickly optimize the sound-sensing state. Can be
[0021]
Although a specific method for optimizing the sound sensing state is not particularly limited, for example, the following method can be used. First, the amplitude of the ultrasonic waves emitted from the plurality of vibrations 31 is set to a small value, and is appropriately attached to each mastoid so that the sound-sensing state is generally good. I do. Then, the frequency and phase of each vibrator 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 becomes the best. Thereafter, by setting the phase of the carrier signal corresponding to each transducer 31 in the same manner, the optimum frequency and phase of the carrier signal can be individually obtained for each transducer 31, and the sound-sensing state Can be optimized. Either setting of the frequency and the phase may be performed first. Finally, the amplitude is set to a desired level so that a desired sound sensing state is obtained.
[0022]
As another method for optimizing the sound sensing state, while maintaining the frequency, phase and amplitude of the carrier signal corresponding to one vibrator 31 at predetermined values, respectively, It is also possible to optimize the sound sensing state by sequentially changing the frequency, phase and amplitude of the sound. In this case, it is sufficient that the frequency, phase and amplitude of the carrier signal corresponding to at least one transducer 31 can be adjusted in the input unit 24.
[0023]
【Example】
Using a time-domain finite difference method (FDTD method: Finite-Difference Time-Domain Method) used for analysis of a sound field in a fluid, a sound field formed in a head by a vibrator is calculated and calculated. The change in the sound pressure distribution due to the difference in the frequency and phase of the carrier signal corresponding to the above was investigated.
[0024]
Specifically, first, a human head model is created with reference to a standard Japanese male head anatomical chart, 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 was simulated as if it had uniform vibration. FIG. 4A is a cross-sectional view of the head model in the xy plane including the cochlea. In FIG. 4, “I”, “II” and “III” indicate the mounting positions of the vibrator I, the vibrator II and the vibrator III, respectively, where “I” is in front of the ear and “II” is in the ear. Behind, "III" is further behind the ear. The excitation waveform applied to the sound source was a continuous sine wave obtained by multiplying a rising wave by a ramp function. As an example, an excitation waveform at 30 kHz is shown in FIG.
[0025]
(Condition 1) Change in sound pressure distribution due to difference in frequency 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 the same (phase difference 0). 5 and 6 show the sound pressure distribution in the cross section of the head shown in FIG. 4 by shading, and the units of the vertical axis and the horizontal axis are mm. FIGS. 5A to 5D correspond to the cases where the frequency of the vibrator II is 15 kHz, 20 kHz, 30 kHz, and 30.001 kHz, respectively. FIGS. The frequencies correspond to 30.01 kHz, 30.1 kHz, 31 kHz and 32 kHz, respectively. FIGS. 7 and 8 show the time (horizontal axis) changes of the sound pressure (vertical axis) in the left cochlea under the frequency conditions corresponding to FIGS. 5 and 6, respectively.
[0026]
As is clear 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 in a predetermined portion also gradually change. As described above, by adjusting the frequency of the carrier signal corresponding to one of the vibrators, the sound sensing state can be controlled.
[0027]
(Condition 2) Change in sound pressure distribution due to phase difference Using the vibrator I and the vibrator II in the above-described head model, the vibrator I and the vibrator I were vibrated while maintaining the frequency of the vibrator I and the vibrator II at 30 kHz. A phase difference with the 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 by shading, and the unit of the vertical axis and the horizontal axis is mm. FIGS. 9A to 9C correspond to the cases where the phase delay of the oscillator II with respect to the phase of the oscillator I is 180 °, 150 °, and 120 °, respectively. (C) corresponds to the case where the phase lag of the vibrator II with respect to the phase of the vibrator I is 90 °, 60 °, and 30 °, respectively. FIGS. 11A to 11C correspond to the case where the phase of the oscillator II advances by 180 °, 150 °, and 120 ° with respect to the phase of the oscillator I, respectively. ) To (c) correspond to the case where the phase advance of the vibrator II with respect to the phase of the vibrator I is 90 °, 60 ° and 30 °, respectively. 13 to 16 show time (horizontal axis) changes in sound pressure (vertical axis) in the left cochlea under frequency conditions corresponding to FIGS. 9 to 12, respectively.
[0028]
As is clear from FIGS. 9 to 16, by gradually changing the phase difference between the excitation waveforms of the plurality of transducers, the sound pressure distribution in the head and the sound level at a predetermined portion also gradually change. As described above, the sound sensing state can be controlled by adjusting the phase of the carrier signal corresponding to one of the transducers.
[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) was 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 by shading, and the unit of the vertical axis and the horizontal axis is mm. FIGS. 17A to 17D correspond to each combination 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 0.
[0030]
As is clear from FIGS. 17 and 18, the sound pressure distribution and the sound pressure level at a predetermined portion are largely changed only by slightly different mounting positions of the vibrator. Thus, it is difficult to optimize the sound sensing state by changing the mounting position of the vibrator.
[0031]
(Condition 4) Sound pressure distribution due to audible sound The sound pressure distribution in the head was examined under the same conditions as in Condition 3 above, except that the frequency of each vibrator was 3 kHz. FIGS. 19A to 19D correspond to each combination of the oscillators I and II, the oscillators II and III, the oscillators I and III, and the oscillators I, II, and III. FIG. 20 shows a change in sound pressure (vertical axis) with time (horizontal axis) in the left cochlea under each condition corresponding to FIG.
[0032]
As is clear from FIGS. 19 and 20, even if the mounting position of the vibrator changes, the sound pressure distribution and the sound pressure level at a predetermined portion hardly change. Thus, in the case of an audible sound, the mounting position of the vibrator has little effect on the sound sensing state.
[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 sectional view of a vibration transmission unit in the external sound perception device.
FIG. 4 is a diagram 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 a head.
FIG. 6 is a diagram showing another example of the analysis result of the sound pressure distribution in the head.
FIG. 7 is a diagram showing a temporal change in sound pressure at a predetermined portion corresponding to FIG. 5;
FIG. 8 is a diagram showing a temporal change in sound pressure at a predetermined portion corresponding to FIG. 6;
FIG. 9 is a diagram illustrating an example of an analysis result of a sound pressure distribution in the head.
FIG. 10 is a diagram showing another example of the analysis result of the sound pressure distribution in the head.
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.
FIG. 13 is a diagram showing a temporal change in sound pressure at a predetermined portion corresponding to FIG. 9;
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. 11;
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 an analysis result of a sound pressure distribution in the head.
FIG. 18 is a diagram showing a temporal change in sound pressure at a predetermined portion corresponding to FIG. 17;
FIG. 19 is a diagram illustrating an example of an analysis result of a sound pressure distribution in the head.
FIG. 20 is a diagram showing a temporal change in sound pressure at a predetermined portion corresponding to FIG. 19;
[Explanation of symbols]
Reference Signs List 10 sound signal generation section 20 vibration signal generation section 22 carrier signal generation section 24 input section 26 carrier signal modulation section 30 vibration transmission section 31 vibrator 32 case 34 sucker

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,
A vibration signal generating unit that generates 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 unit includes a plurality of vibrators that can be fixed in a state of being in contact with a predetermined position of a living body,
The external sound perception device, wherein the vibration signal generation means is configured to be able to generate the different vibration signals for each of the vibrators. The external sound perception device according to claim 1, wherein the vibration signal generation unit includes an input unit that can adjust a frequency and / or a phase of the carrier signal corresponding to at least one of the vibrators.

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