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JP2002300688

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DESCRIPTION JP2002300688
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
sound source device that emits sound signals in a human-readable range, and in particular, a
virtual sound source is configured in space and the sound source is limitedly available to specific
individuals. The present invention relates to a sound source device suitable for a personal
communication sound source device.
[0002]
[Prior Art] Space-based acoustic communication has been conducted since the beginning of
humanity, but it is a speaker with poor directivity when viewed from the viewpoint of the human
mouth as a sound source, and it has poor secrecy and interception It is a communication method
that is easy and has many drawbacks according to the view that it affects noise as the
surrounding third parties. At present, there are situations where it is clear that you want to
protect privacy when you look at the state of acoustic communication in society, and conversely,
there are many cases where information between other people you do not want to hear overflows
in general places.
[0003]
For example, when a visually impaired person or the like needs to operate the ATM, it is desirable
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to perform the ATM operation by giving information shown on the screen or an instruction for
the next operation, but it is preferable to use the usual speaker At present, the follow-up people
who are waiting for the turn and the people around them will be heard at the same time. Further,
with the recent development of computers, there are not a few things that the operation proceeds
interactively by exchanging voice information, but the voice information is only unnecessary
sound information for the person around the operator.
[0004]
Conventionally, devices for transmitting acoustic signals to specific locations in space exist and
have been commercialized. As one of the methods, the audible sound sources (speakers) are
arranged in a plane or in a line, the radiation direction of the sound waves is adjusted, and the
phase of the sound source at the edge portion is reversed, etc. There is a method to emphasize
Then, it is possible to listen to an audible sound wave emitted from the ceiling only in a certain
area, or to increase the volume of the vicinity of the person with mild hearing loss when listening
to TV. Used for the purpose of For example, the product name "Enhanced Speaker" by Matsushita
Electric Industrial Co., Ltd. is a local sound pressure enhancement speaker for the purpose of
enabling a hearing impaired person to listen to a television with his family when the person is in
the family.
[0005]
In addition, in another method using parametric array effect, a desired number of transducers
are integrated to ensure a desired sound pressure, and a two-dimensional array effect of
arranging transducers in a two-dimensional array directivity of audible sound. It has been
considered how to fix the
[0006]
However, in the former method using a normal audio source, the size of the audible space is
relatively large because the direction control of the sound source is performed at the level of a
long wavelength audible sound wave, and only a small number of listeners including individuals
The function is insufficient as a device to listen to.
On the other hand, in the latter method, it is necessary to arrange a large number of transducers
in a two-dimensional manner as a sound source because the demodulation efficiency of the
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parametric array effect is low. The sound source position of the audible sound is not fixed at a
fixed position because the sound is continuously demodulated and generated, and the listener is
made to feel an unnatural sound source position.
[0007]
Therefore, the applicant has already proposed a method of making one point in space a virtual
sound source by applying a parametric array effect to reflect and converge a sound wave
(Japanese Patent Application Laid-Open No. 7-107588). According to this method, an ultrasonic
wave whose amplitude is modulated by an audible sound signal is emitted from, for example, one
focal point of the inner surface of the spheroid toward a part of the inner surface of the spheroid,
and the sound wave is reflected and the other is reflected. Uses the progress of the sound wave
that converges to the focal point and diverges again. That is, by listening to the sound in the
diverging area after the reflected wave has converged, a sound source device of an audible sound
is proposed as if the convergence point can be heard as a sound source.
[0008]
This method is based on the parametric array effect in which ultrasonic waves amplitudemodulated by audible sound are demodulated while propagating in space to derive an audible
sound component, and waves emitted from one focal point on the inner surface of the tumbling
ellipsoid have the same inner surface. And the principle of passing through the other focus after
reflection. In this method, since the ultrasonic waves emitted by the transducer can be converged
efficiently, the audible sound demodulated by the parametric array effect can be heard at a
relatively high level. In addition, since one point (near the convergence point) in a physically
empty space becomes a sound source, the above sound source can be installed near the listener's
face or ear, making it extremely useful as a sound source for personally listening to acoustic
information. Is an excellent method.
[0009]
[Problems to be Solved] The technique of constructing a virtual sound source in the air by using
the parametric array effect and the reflection convergence of the inner surface of the spheroid
shown in the preceding paragraph has the drawback of the conventional space-based acoustic
communication. Although it will improve and various applications can be considered, it has the
following subjects.
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[0010]
That is, an audible sound wave generated by this method is derived from an ultrasonic wave that
is amplitude-modulated by an audible sound signal, and the derivation mechanism is due to the
non-linear characteristic of air against the sound wave.
The higher the sound pressure of the ultrasonic wave, the more characteristically this effect
occurs in an accelerated manner. In addition, since the effect is generated one after another at
the speed at which the ultrasonic wave travels along the course of the ultrasonic wave, there is a
property that the effect is generated during the propagation of the sound wave and accumulated
and grown. Therefore, the audible sound is generated relatively frequently at the central portion
where the sound pressure is high in the traveling direction of the ultrasonic wave, and can be
heard as a very high-directional audible sound.
[0011]
Here, if an angle up to 3 dB attenuation from the sound pressure at the central axis of the sound
wave is defined as the radiation angle α of the sound wave, the radiation angle α is the size of
the reflection surface that reflects the ultrasonic wave or the radiation angle of the ultrasonic
transducer But it is about 10 degrees or less. Although this has the feature that the directivity is
very high when viewed as a sound source, it has the following disadvantages. It is convenient to
send the sound wave to either the left or right ear canal because the sound wave is close to a
beam shape, but it is a virtual sound source so that it can be heard by both ears to localize the
position of the sound source properly. It must be quite far from the point. In addition, in the
sound wave state close to a beam, the sound pressure drop with progress is small because the
sound wave does not expand in the space area after the sound wave convergence so much that
there is a problem that sound is heard in unexpected places due to reflection on the wall etc. The
[0012]
Furthermore, in addition, the sound waves of any sound waves generated from a normal
vibrating body spread in the form of concentric circles from the vibrating body, and the auditory
senses the direction and distance using input signals from both ears . In this case, in principle,
the sound wave has no directivity, and when the listener turns to the sound source direction, the
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binaural input becomes the same level. When the sound source deviates from the front, the
estimation of the direction is performed by detecting the subtle level difference and time
difference of the input sound signal to both ears, and the recognition of the distance seems to be
due to the detection of the curvature of the sound wave front. ing.
[0013]
This kind of work of hearing is important in grasping the environment of the sound, and
conversely listening to the sound which can not grasp such information is fatigued when it is
unnatural or anxious and listened for a long time It is thought to bring Therefore, presenting
sound information that can be naturally localized is an important factor. On the other hand, if the
level difference between the sounds listened to by both ears is large because the directivity is too
high, the normal sound source localization can not be performed.
[0014]
The present invention aims to solve the above-mentioned problems in a sound source
configuration apparatus for converging a sound wave by a parametric array effect and a
reflection surface, and a virtual sound source whose sound source is near the convergence point
and whose sound is heard after the convergence point It is an object of the invention to widen
the angle α and stabilize sound source localization by binaural hearing and to reduce the sound
pressure in an area far from the convergence point unnecessary for listening. That is, when the
radiation angle α is wide, even if the virtual sound source is relatively close, both ears are within
the radiation angle α, so that stable sound source localization is performed and it can be heard
as natural sound. In addition, another effect of the wide radiation angle α of the virtual sound
source is that the sound pressure converges sharply and diverges rapidly, so the sound pressure
drops sharply as it gets away from the sound source. There is an advantage that a large level of
sound wave does not fly to unnecessary space outside the listening area.
[0015]
According to a first aspect of the present invention, there is provided a modulation means for
amplitude-modulating an electric signal of an ultrasonic frequency band by an electric signal of
an audible frequency band, and a mechanical vibration of the modulated electric signal of the
modulation means. Several transducers T1, T2,. . . And the above transducers T1, T2,. . . And (1:
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1) corresponding to the transducers T1, T2,. . . Curved surface S1, S2... As acoustic reflection
means for reflecting the sound wave emitted by the light source in a predetermined direction. . .
And the curved surface S1, S2. . . Are the spheroids Er1, Er2 corresponding to (1: 1) respectively.
. . And the spheroid Er1, Er2. . . , And second focal points F21, F22,... In directions different from
each other with respect to a common first focal point F1o occupying the same position and the
first focal point F1o. . . And the above-mentioned transducers T1, T2,. . . Is a target to which a
sound wave is to be emitted. . . The above-mentioned spheroid Er1, Er2. . . Second focal points
F21, F22,. . . The sound source configuring apparatus according to the present invention is
arranged at the position of
[0016]
A sound source configuring apparatus according to the present invention comprises: modulation
means for amplitude-modulating an electrical signal of an ultrasonic frequency band with an
electrical signal of an audible frequency band; and a sound wave by converting the modulated
electrical signal of the modulation means into mechanical vibration. Several transducers T1, T2,. .
. And a plurality of curved surfaces S1, S2. . . And. Also, the individual curved surfaces S1, S2. . .
Are the transducers T1, T2,. . . And (1: 1), and the transducers T1, T2,. . . Reflects the sound
waves emitted by the light source in a predetermined direction.
[0017]
In the sound source configuration apparatus according to the present invention, a sound wave
from an ultrasonic transducer driven by an ultrasonic wave band signal amplitude-modulated by
an audio sound wave signal such as voice propagates in the air, and the sound wave non-linear
characteristic of air in sound wave. It utilizes the so-called parametric array effect that is
demodulated by. Then, in the demodulated audio sound wave, components in the same direction
as the ultrasonic signal that is the carrier are constructive to have directivity (the formation of a
highly directional sound source).
[0018]
The first point to be particularly noted in the present invention is the curved surfaces S1, S2. . . Is
a spheroid Er1, Er2. . . And (1: 1) corresponding to the spheroid Er1, Er2. . . And the spheroid
Er1, Er2. . . , And second focal points F21, F22,... Having different directions with respect to the
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common first focal point F1o at the same position and the first focal point F1o. . . And to have.
[0019]
Next, the second point to be particularly noted in the present invention is that the transducers
T1, T2,. . . Is a target to which a sound wave is to be emitted. . . The above-mentioned spheroid
Er1, Er2. . . Second focal points F21, F22,. . . It is to be placed in the position of.
[0020]
The point to be noted in relation to the second invention described later is that in the present
invention, the spheroids Er1, Er2. . . The shape and size of the light source are not limited to the
same, and the distances between the respective focal points (F1o-F21), (F1o-F22),. . . Is a point
not limited to a fixed value. However, in this case, the curved surface Sn (n = 1, 2,... ) Any point P
n (n = 1, 2, ...) And the two focal points F1o, F2n (n = 1, 2,. Preferably, the sum Dn (= D1n + D2n)
of the distances D1n and D2n between them) is the same value (that is, Dn = constant value). The
above distance D n (n = 1, 2,... When the value of) is different depending on n, the phase of the
sound wave converging to the focal point F1o is curved surface Sn (n = 1, 2, ... ), Which partially
cancels out the intensity of the sound waves and reduces the superposing efficiency of the sound
waves.
[0021]
As a result, transducers T1, T2,. . . The sound waves emitted from are respectively curved
surfaces S1, S2. . . , And both of the curved surfaces S1 and S2. . . The light beam converges to
the first focal point F1o, which is the focal point, and then diverges. The reason is that the
spheroid has two foci inside, and the sound wave originating from one focal point as the origin is
run at an equal distance after being reflected once on the inner surface of the spheroid no matter
what direction it is emitted It has a feature of passing through one focal point, and in the present
invention, the curved surfaces S1, S2. . . Have a common focal point F1o and the other focal
points F21, F22,. . . Since the transducer is placed at the center, all the reflected waves converge
to the focal point F1o.
[0022]
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And, in the sound source configuration device according to the present invention, a plurality of
transducers T1, T2,. . . And curved surfaces S1, S2. . . And the convergence direction of the sound
wave converged to the focal point F1o in each set can be changed variously, and the convergence
angle of the sound wave as the whole set (device) And the radiation angle α from the
convergence point can be broadened.
[0023]
That is, since the demodulation of the amplitude-modulated ultrasonic waves in each unit has the
property of effectively occurring at a place where the ultrasonic amplitude is large, the
demodulation occurs intensively near the focal point F1o which is the convergence point and
after passing through the focal point A large amount of audible sound waves will be included in
the sound waves, and when listening to the sound in this diverging space area, it will sound as if
there is an audible sound source at the focal point F1 o (formation of a highly directional virtual
sound source). Then, the number of units of this convergent sound wave (sound source) is
increased, and the curved surfaces S1, S2. . . By widening the overall spatial angle, it is possible to
realize a state in which sound waves from multiple directions gather at the focal point F1o and
re-emit, so that audible sound can be heard in a wide radiation angle range after convergence
(sound source Widening of the radiation angle α of Also, the shape of the sound wave
divergence after convergence is the curved surface S1, S2. . . By variously devising the
arrangement mode of, it becomes possible to obtain various diverging shapes such as, for
example, long in the lateral direction or circularly large (diversification of sound source shapes).
[0024]
As a result, in the sound source configuration device according to the present invention, the
radiation angle α from the sound source of the audible sound wave can be easily spread, and
even if the virtual sound source is relatively close to the listener Inside, stable sound source
localization is performed and you can listen as natural sound. Further, since the radiation angle
α of the sound source can be broadened, the sound wave can be spatially sharply converged and
then sharply diverged, whereby the sound pressure will drop sharply as it gets away from the
sound source, Unwanted space outside the listening area can be prevented from flying large
levels of sound waves.
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[0025]
Next, according to a second aspect of the present invention, there is provided a modulation
means for amplitude-modulating an electrical signal of an ultrasonic frequency band by an
electrical signal of an audible frequency band, and a sound wave which converts the modulated
electrical signal of the modulation means into mechanical vibration. Multiple transducers T1, T2,.
. . And the above transducers T1, T2,. . . And (1: 1) corresponding to the transducers T1, T2,. . .
Curved surface S1, S2... As acoustic reflection means for reflecting the sound wave emitted by the
light source in a predetermined direction. . . And the curved surface S1, S2. . . The curved surface
So itself or a part thereof is replicated by rotating the axis of the spheroid with the curved
surface So forming a part of the spheroid as the center of rotation of the first focal point F1 of
the spheroid. The above-mentioned transducers T1, T2,. . . Is a target to which a sound wave is to
be emitted. . . The second focal point F2 n (n = 1, 2,... Of the spheroid containing The sound
source configuring apparatus according to the present invention is characterized in that it is
disposed at the position of.
[0026]
A sound source configuring apparatus according to the present invention comprises: modulation
means for amplitude-modulating an electrical signal of an ultrasonic frequency band with an
electrical signal of an audible frequency band; and a sound wave by converting the modulated
electrical signal of the modulation means into mechanical vibration. Several transducers T1, T2,. .
. And a plurality of curved surfaces S1, S2. . . And. And each curved surface S1, S2. . . Are the
transducers T1, T2,. . . And (1: 1), and the transducers T1, T2,. . . Reflects the sound waves
emitted by the light source in a predetermined direction.
[0027]
The first point to be particularly noted in the present invention is the curved surfaces S1, S2. . .
The curved surface So itself or a part thereof is replicated by rotating the axis of the spheroid
with the curved surface So forming a part of the spheroid as the center of rotation of the first
focal point F1 of the spheroid. It is a partial curved surface to constitute. That is, the curved
surfaces S1, S2. . . Are spheroid Er1, Er2,. . . Of the individual curved surfaces S1, S2. . . The
respective spheroids Er1, Er2,. . . Share the same focus F1. In the above, the rotation of the axis of
the spheroid about F1 means that the axis is simply moved in a fixed direction so that one point
on the axis draws a circle. Instead, it means that the angle of the moving axis with respect to the
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reference axis is changed in any direction. Therefore, for example, various movement modes such
as movement of the curved surface So whose direction is changed zigzag and movement in a
spiral manner are included.
[0028]
The main difference between the present invention and the first invention is that, in the present
invention, the individual curved surfaces S1, S2. . . The respective spheroids Er1, Er2,. . . The
shape and the size of are the same, so that the distances between the first and second focal
points are all the same, and only their directions are different. In this respect, the sound source
configuring apparatus of the first invention can cope with various shapes and includes various
shapes, but the present invention is relatively limited in shape and relatively designed and
manufactured. It can be said that it is easy. The other aspects are the same as in the first aspect
of the invention, and similar actions and effects can be obtained.
[0029]
Next, according to a third aspect of the present invention, there is provided a modulation means
for amplitude-modulating an electrical signal of an ultrasonic frequency band by an electrical
signal of an audible frequency band, and a sound wave which converts the modulated electrical
signal of the modulation means into mechanical vibration. , And curved surfaces S1, S2,... As
acoustic reflection means for reflecting the sound waves emitted by the transducers in a
predetermined direction. . . And the curved surface S1, S2. . . Are the spheroids Er1, Er2. . . And
the spheroid Er1, Er2. . . , And second focal points F21, F22,... In directions different from each
other with respect to a common first focal point F1o occupying the same position and the first
focal point F1o. . . And the curved surfaces S1, S2,. . . A set of transducers T1s, T2s,. . . Or an
array of transducers T1a, T2a,. . . , And the curved surfaces S1, S2,. . . The synthetic wave on the
curved surface Sn of the sound wave emitted from the set Tns of transducers or array Tna that
emits the acoustic wave toward any curved surface Sn in the second surface F2n of the spheroid
Ern including the curved surface Sn In the sound source configuration device, the wave front has
a wave front similar to that of a sound wave emitted from a single transducer placed at the
position of.
[0030]
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According to the present invention, in the first invention, the curved surfaces S1, S2,. . . A set of
transducers T1s, T2s,. . . Or an array of transducers T1a, T2a,. . . Corresponds to (1: 1), and the
set of transducers T n (n = 1, 2,. Or array Tna (n = 1, 2,...) Curved surface Sn (n = 1, 2, ...) of the
sound wave emitted from The synthetic wave on the upper surface has a wave front substantially
identical to the wave front of a sound wave emitted from a single transducer placed at the second
focal point F2 n of the spheroid Ern containing the curved surface Sn. is there.
[0031]
The set of transducers T n (n = 1, 2,. Or array Tna (n = 1, 2,...) Curved surface Sn (n = 1, 2, ...) of
the sound wave emitted from ) The synthetic wave on the top has a wave front similar to that of a
sound wave emitted from a single transducer placed at the second focal point F2 of the spheroid,
so from any curved surface Sn The reflected wave is substantially the same as the sound source
configuring device of the first invention. Therefore, the present invention can also obtain the
same action and effect as the first invention.
[0032]
Further, in the present invention, the transducer or transducer array Tna constituting the
transducer set Tns does not have to be disposed at the position of the second focal point F2n of
the curved surface Sn. Therefore, the curved surface Sn (n = 1, 2,... ) That the reflected wave
(secondary wave) is not blocked or scattered by the transducer or the transducer array Tna, even
if the sound wave (secondary wave) reflected from the) passes through the vicinity of the second
focal point F2n It can. That is, even if the reflected wave (secondary wave) passes through the
second focal point F2, all the reflected wave (secondary wave) can be converged to the focal
point F1. Therefore, the curved surface Sn (n = 1, 2,... ) Can be a curved surface near the surface
through which the rotation axis of the spheroid passes. And, it is relatively easy to produce a
symmetrical curved surface formed around the rotation axis of the spheroid.
[0033]
Next, according to a fourth aspect of the present invention, there is provided a modulation means
for amplitude-modulating an electric signal of an ultrasonic frequency band by an electric signal
of an audible frequency band, and a sound wave which converts the modulated electric signal of
the modulation means into mechanical vibration. , And curved surfaces S1, S2,... As acoustic
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reflection means for reflecting the sound waves emitted by the transducers in a predetermined
direction. . . And the curved surface S1, S2. . . The curved surface So itself is replicated by
rotating the axis of the spheroid Ero, with the curved surface So forming a part of the spheroid
Ero being the center of rotation of the first focal point F1o of the spheroid Ero. It is a partial
curved surface which constitutes a part, and said curved surface S1, S2,. . . A set of transducers
T1s, T2s,. . . Or an array of transducers T1a, T2a,. . . Corresponds to (1: 1), and the curved
surfaces S1, S2,. . . A set of transducers Tns (n = 1, 2, ...) for emitting sound waves toward any
curved surface Sn in Or array Tna (n = 1, 2,...) The synthetic wave on the curved surface Sn of the
sound wave emitted from the) is a wave front similar to the wave front of the sound wave emitted
from a single transducer disposed at the second focal point F2 n of the spheroid containing the
curved surface Sn. In a sound source configuration apparatus characterized in that
[0034]
According to the present invention, in the second invention, the curved surfaces S1, S2,. . . A set
of transducers T1s, T2s,. . . Or an array of transducers T1a, T2a,. . . Correspond to (1: 1), and the
set Tns or array Tna (n = 1, 2,. Curved surface Sn (n = 1, 2, ...) of the sound wave emitted from ) Is
the second focal point F2 n (n = 1, 2,... Of the spheroid including the curved surface Sn). The
wavefront of the sound wave emitted from a single transducer placed at the position of) is made
to have substantially the same wavefront.
[0035]
The set Tns or array Tna of transducers according to the invention (n = 1, 2, ... Curved surface Sn
(n = 1, 2, ...) of the sound wave emitted from ) Is arbitrary because it has a wave front similar to
that of a sound wave emitted from a single transducer placed at the second focal point F2 n of
the spheroid containing the curved surface Sn. The reflected wave from the curved surface Sn is
substantially the same as the sound source configuring device of the second invention. Therefore,
the present invention can also obtain the same action and effect as the second invention.
[0036]
Then, as in the third aspect of the invention, the transducers or transducer array Tna constituting
the transducer set Tns need not be placed at the position of the second focal point F2n of the
curved surface Sn. Therefore, all reflected waves (secondary waves) can be easily configured to
09-05-2019
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converge on the focal point F1. Therefore, the curved surface Sn (n = 1, 2,... ) Can be a curved
surface in the vicinity of a plane orthogonal to the rotation axis of the spheroid.
[0037]
According to the first to fourth inventions, as described in claim 5, the curved surfaces S1, S2,. . .
Are connected to adjacent curved surfaces without breaking, and curved surfaces S1, S2,. . .
Preferably, the whole of Thus, the curved surfaces S1, S2,. . . Are connected seamlessly, and each
surface S1, S2,. . . The surface S1, S2,. . . , And the whole of the sound wave reflected to the focal
point F1 can be integrated without break. And curved surface S1, S2. . . By variously devising the
arrangement mode, it is possible to form the shape of the audible area of the sound wave in
various cross-sectional shapes such as, for example, long in the lateral direction or large in a
circle.
[0038]
Next, according to a fifth aspect of the present invention, there is provided a modulation means
for amplitude-modulating an electrical signal of an ultrasonic frequency band by an electrical
signal of an audible frequency band, and a sound wave which converts the modulated electrical
signal of the modulation means into mechanical vibration. And a curved surface Sr as acoustic
reflecting means for reflecting a sound wave transmitted by the transducer in a predetermined
direction, wherein the curved surface Sr is a plane including an ellipse Eo. The transducer is a
curved surface formed as a locus described by an elliptic arc Co forming a part of the ellipse Eo
when rotated in an arbitrary direction with the first focal point F1 of Eo as the center of rotation.
The second focal point F2 of the ellipse Eo in the case where the ellipse Eo is rotated is disposed
on the line drawn, and the installation position of the transducer and the curved surface Sr The
amount of rotation of the plane including the above-mentioned ellipse Eo is used as a quantity
defining the position of the elliptic arc Co of the case where the angular variable (θ, ψ) of polar
coordinates with the focal point F1 as the origin is adopted. The radiation direction is directed in
the direction of an elliptic arc Co having the same angle variable (θ, ψ) as the above-mentioned
angle variable (θ, ψ) representing the installation position of the transducer. .
[0039]
A sound source configuring apparatus according to the present invention comprises: modulation
means for amplitude-modulating an electrical signal of an ultrasonic frequency band with an
electrical signal of an audible frequency band; and a sound wave by converting the modulated
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13
electrical signal of the modulation means into mechanical vibration. It has a plurality of
transducers that emit light, and a curved surface Sr as acoustic reflection means that reflects the
sound waves emitted by the transducers in a predetermined direction.
In the above, a plurality of transducers is a concept including a so-called transducer array in
which the transducers are spatially continuously and linearly arranged in a line or plane, in
addition to the case where a plurality of transducers are arranged at a distance.
[0040]
The first point to be particularly noted in the present invention is that the curved surface Sr
rotates a plane including the ellipse Eo as a plane curve in an arbitrary direction with the first
focal point F1 of the ellipse Eo as the center of rotation. In this case, it is a curved surface formed
as a locus drawn by an elliptic arc Co which forms a part of the ellipse Eo.
[0041]
In the above, the rotation of the flat surface E0, which is the base of the curved surface Sr, about
the focal point F1 of the ellipse Eo is simply moved in a fixed direction so that one point on the
reference plane draws a circle. It does not mean that, but it means that one point on the plane
changes the angle continuously in any direction.
Thus, for example, various movement modes such as rotation of a reference plane in which one
point on the plane turns in a zigzag direction are included. Therefore, as a general theory, the
curved surface Sr also includes complicated shapes, but what is common is that there is an ellipse
Eo inscribed here at all points on the curved surface Sr. However, in the simplest example of
design and manufacture, as described in claim 7, the reference plane including the ellipse Eo
passes through the first focal point F1 of the ellipse Eo and an axis parallel to the minor axis of
the ellipse Eo. There is an example of a curved surface Sr which is formed as a locus drawn by an
elliptic arc Co which forms a part of the above-mentioned ellipse Eo when it is rotated in a fixed
direction centering on.
[0042]
A second point to be particularly noted in the present invention is that the transducer is disposed
09-05-2019
14
on a curve Lr drawn by the second focal point F2 of the ellipse Eo when the ellipse Eo is rotated
in the same manner. is there. Preferably, a large number of transducers are arranged in an array
or arrangement on the curve Lr.
[0043]
A third point to be particularly noted in the present invention is that the radiation direction of the
sound wave emitted from the above-mentioned transducer is set as follows. That is, the amount
of rotation of the plane including the ellipse Eo is used as the amount of defining the installation
position of the transducer and the position of the elliptic arc Co on the curved surface Sr, and
polar variable angle variables (θ, ψ) with the focal point F1 as the origin In this case, the
radiation direction of the sound wave emitted from the transducer is directed in the direction of
the elliptic arc Co having the same angle variable (θ, ψ) as the angle variable (θ, ψ)
representing the installation position of the transducer There is. That is, the transducer T (θ, ψ)
is located at the second focal point F2 of the elliptic arc Co (θ, ψ) in the direction to direct the
sound wave, and as a result, the curved surface of the sound wave emitted from the transducer T
(θ, ψ) The reflected waves from Sr all converge in the vicinity of the common focal point F1.
[0044]
And, since the number of the transducers is plural, the radiation angle α of the sound wave from
the virtual sound source can be expanded for the same reason as described in the first invention,
and the same as the sound source configuring device of the first invention An effect can be
obtained.
[0045]
In the sound source configuration apparatus according to the fifth aspect of the present
invention, as described in claim 8, the transducer is a transducer array continuously disposed on
a line drawn by the second focus F2 of the ellipse Eo. Is preferred.
By this, it is possible to widen the radiation angle α of the sound source and to form a uniform
sound wave bundle without unevenness in the direction of the line drawn by the focal point F2.
[0046]
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15
Then, as described in claim 9, in the sound source configuration apparatus according to the first
to fifth inventions described above, the amount of reflection of the reflected wave on the curved
surface of the sound wave emitted from the transducer on the transducer itself is reduced.
Preferably, the radiation direction of the sound wave emitted from the transducer, the incident
position of the sound wave on the curved surface, and the like are set. The reflected wave
(secondary wave) that abuts on the transducer itself will reduce the amount of sound waves that
can be heard within the listening area by scattering or will be heard outside the predetermined
listening area It is from.
[0047]
For this purpose, for example, as described in claim 10, the transducer is placed in the vicinity of
the second focal point F2 of the ellipse Eo inscribed in the reflection surface to which the
acoustic wave is directed, and the radiation direction of the acoustic wave emitted from the
transducer is There is a method of setting on a line off the axis connecting the two focal points
F1 and F2 of the ellipse Eo inscribed in the reflection surface to which the sound wave is directed
(see FIGS. 2 and 7 of the first and third embodiments). If there is a radiation wave (primary wave)
on the axis connecting the two focal points F1 and F2, the reflected wave (secondary wave)
passes through the focal point F1 and the reflected wave (secondary wave) collides with or
scatters the transducer To However, by making the direction of the radiation wave (primary
wave) different from the axis connecting the focal points F1 and F2, the reflected wave
(secondary wave) is less likely to collide with or scatter the transducer itself. .
[0048]
The arrangement position of the transducers or the shape of the reflection curved surface of the
sound wave in the first to fifth inventions represents an ideal concept, and it is not necessary to
be strictly strict in practice. The degree of convergence only slows down. Further, it goes without
saying that the shape of the surface other than the portion that reflects the sound wave may be
formed in any shape.
[0049]
09-05-2019
16
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 In this
embodiment, as shown in FIGS. 1 and 3, a modulation circuit unit 41 (which modulates the
amplitude of an electrical signal in the ultrasonic range with an electrical signal in the audible
range) 3) and a plurality of transducers Tn (n = 1, 2,...) For converting the modulated electric
signal of the modulation circuit unit 41 into mechanical vibration and transmitting an acoustic
wave. And the above transducers Tn (n = 1, 2,...) ) And (1: 1) corresponding to transducers Tn (n
= 1, 2,...) Curved surface Sn (n = 1, 2,...) As acoustic reflecting means for reflecting the sound
wave 61 emitted by And the sound source configuration apparatus 1.
[0050]
Then, as shown in FIGS. 1 and 2, the curved surface Sn (n = 1, 2,... Are the spheroids Ern (n = 1,
2,...) Corresponding to (1: 1) respectively. And the spheroid Ern (n = 1, 2,... , And the second focal
point F2 n (n = 1, 2,...) In directions different from each other with respect to the common first
focal point F1 o occupying the same position and the first focal point F1 o. And.
[0051]
Further, as shown in FIG. 1, the curved surface Sn (n = 1, 2,... ) Is a curved surface reproduced by
rotating the axis of the spheroid Er1 with the curved surface S1 forming a part of the spheroid
Er1 as the center of rotation of the first focal point F1o of the spheroid Er1 The rotation angle of
the curved surface S1 is set to 0). Then, as shown in FIGS. 1 and 2, the transducers Tn (n = 1, 2,...
) Is a target to which the sound wave 61 is emitted (n = 1, 2,...) Spheroid Ern (n = 1, 2, ...)
including ) Of the second focal point F 2 n (n = 1, 2,. ) Is placed.
[0052]
Also, curved surface Sn (n = 1, 2,. ) Is connected so as to be continuous with the adjacent curved
surface, and the whole is integrated. Then, as shown in FIG. 2, the transducers Tn (n = 1, 2,...
Curved surface Sn (n = 1, 2,...) Of the sound wave 61 emitted from ) Is the transducer T n (n = 1,
2,...) ) Transducers T n (n = 1, 2,...) To reduce the amount of contact with itself. ) And the curved
surface Sn (n = 1, 2,...) Of the sound wave 61 The incident position etc. to) is set. That is, the
transducers Tn (n = 1, 2,... The direction of radiation of the sound wave 61 emitted from the
surface of the curved surface Sn (n = 1, 2,. ) Of the two focal points F1o and F2n (n = 1, 2,...) Of
the ellipse Eo (= spheroid Ern) inscribed in On a line inclined to the axis connecting the
09-05-2019
17
[0053]
The following will supplement the description of each. As shown in FIG. 3, the modulation circuit
unit 41 has a modulator 413 that amplitude-modulates the carrier of the ultrasonic frequency
band emitted by the oscillator 412 by the electrical signal of the audio frequency band emitted
by the signal generator 411. And, a plurality of transducers Tn (n = 1, 2, ... , Respectively convert
the modulated electrical signal emitted by the modulator 413 into mechanical vibration and emit
an ultrasonic wave.
[0054]
As shown in FIG. 1, transducers Tn (n = 1, 2,... Is a curved surface Sn (n = 1, 2,. Spheroid Ern (n =
1, 2, ...) including ) Of the second focal point F 2 n (n = 1, 2,. ) Is placed. As a result, the
transducers Tn (n = 1, 2, ... The sound waves emitted from) are respectively curved surface Sn (n
= 1, 2, ...) ), And each of them is a curved surface Sn (n = 1, 2,...) ) Converges to the first focal
point F1o, which is a common focal point of the lens), and then diverges. That is, in this example,
curved surface Sn (n = 1, 2,...) Which is a partial surface of the spheroid surface. ) Has a common
focal point F1o, so curved surface Sn (n = 1, 2,... ) All converge on the focal point F1o.
[0055]
On the other hand, since the demodulation by the parametric array effect has the property of
occurring efficiently in the place where the ultrasonic amplitude is large, the demodulation
occurs intensively near the focal point F1o which is the convergence point, and listening to the
sound in the diverging space region thereafter Sounds as if there is an audible sound source near
the focal point F1o. Then, in the sound source configuration device 1 according to the present
example, a plurality of transducers T1, T2,. . . And curved surfaces S1, S2. . . Sound source units
On (n = 1, 2,. And the radiation angles α n (n = 1, 2,..., See FIGS. 1 and 2) from the convergence
point F1 o are integrated. The convergence angle at which the sound wave converges as a whole
of the device 1 and the radiation angle αt from the convergence point F1o can be widened
(widening of the sound source). In addition, in the radiation angle α n shown in FIGS. 1 and 2,
the additional symbols (h) and (v) indicate the spread angle in the lateral direction and the spread
angle in the longitudinal direction of the radiation angle, respectively.
09-05-2019
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[0056]
Also, curved surface Sn (n = 1, 2,... Is the adjacent curved surface Sm (m = 1, 2,...) ) And each
transducer Tn (n = 1, 2, ... It is possible to prevent a break between the sound waves 61 emitted
from the) and to reduce unevenness in sound intensity within the above-mentioned radiation
angle αt as a whole.
[0057]
In FIG. 1, curved surface Sn (n = 1, 2,..., In order to facilitate understanding and explanation). ) Is
linearly arranged in the lateral direction, but the curved surface Sn (n = 1, 2,... The radiation angle
.alpha.t can be spread in a balanced manner in the vertical and horizontal directions by arranging
two-dimensionally (see, for example, FIG. 4).
[0058]
As a result, in the sound source configuration device 1 according to this example, even if the
virtual sound source described above is relatively close to the listener 81 (FIG. 2), both ears enter
within the radiation angle αt and stable sound source localization is performed. I can hear it as a
natural sound. In addition, since the radiation angle αt of the sound source can be broadened,
the sound wave can be rapidly diverged after being sharply converged in the vicinity of the
listener 81. Therefore, the sound pressure drops rapidly as it gets away from the virtual sound
source (the focal point F1o), and it is possible to prevent the sound wave of a large level from
flying into the space outside the listening area.
[0059]
As described above, according to the present embodiment, it is possible to obtain the sound
source configuration apparatus 1 suitable for a personal communication sound source device or
the like in which a virtual sound source is configured in space and the above-mentioned sound
source can be limitedly used by a specific individual. Can.
[0060]
09-05-2019
19
Embodiment 2 In this embodiment, as shown in FIGS. 5 and 6, a modulation circuit unit 41 (not
shown in FIG. 3, see FIG. 3) amplitude-modulates the electric signal in the frequency of the
ultrasonic range by the electric signal of the frequency in the audible range. And a plurality of
transducers Tn (n = 1, 2,...) For converting the modulated electric signal of the modulation circuit
unit 41 into mechanical vibration and transmitting an acoustic wave.
And the above transducers Tn (n = 1, 2,...) And the curved surface Sr as acoustic reflecting means
for reflecting the sound wave 61 emitted in the predetermined direction.
[0061]
When the curved surface Sr rotates a plane including the ellipse Eo in a fixed direction about an
axis Ax parallel to the minor axis of the ellipse Eo, passing through the first focal point F1 of the
ellipse Eo as shown in FIG. The curved surface is formed as a locus drawn by an elliptic arc Co
forming a part of the above-mentioned ellipse Eo. Also, the transducers Tn (n = 1, 2,... In the case
where the ellipse Eo is rotated in the same manner, as shown in FIG. 5, a large number is
arranged on the arc Ro drawn by the second focal point F2 of the ellipse Eo. In FIG. 5, Tmax
denotes a transducer at the end, and a hatched curved surface Srb denotes the back surface of
the curved surface Sr which is a reflecting surface.
[0062]
そして、トランスジューサTn(n=1,2,... ) Using the amount of rotation of the plane
including the above-mentioned ellipse Eo as an amount defining the position of the elliptic arc Co
on the curved surface Sr and the angular variable (θ, 極) of polar coordinates with the focal
point F1 as the origin. Above), the above-mentioned transducers Tn (n = 1, 2,... The direction of
radiation of the sound wave 61 emitted from) can be detected by the transducer Tn (n = 1, 2,... )
Is directed around an elliptic arc Co having the same angle variable (θ, ψ) as the above angle
variable (θ, ψ) representing the installation position of.
[0063]
That is, the transducer Tn (θ n, ψ n) is at the position of the second focal point F2 of the elliptic
09-05-2019
20
arc Co (θ n, ψ n) in the direction in which it directs the sound wave 61. As a result, the
transducers T n (n = 1, 2,. .. All the reflected waves 62 from the curved surface Sr of the sound
wave 61 emitted from the) are converged in the vicinity of the common focal point F1. As a
result, for the same reason as described in the first embodiment, a virtual sound source is formed
in the vicinity of the focal point F1.
[0064]
そして、トランスジューサTn(n=1,2,... Because a large number of) are arrayed,
the radiation angle .alpha.t of the sound wave from the virtual sound source as the whole of the
device 10 is the lateral direction (left and right direction) of the listener 81 for the same reason
as described in the first embodiment. Can be extended to
[0065]
Although FIG. 5 shows an example in which the elliptic arc Co is moved in the lateral direction
and the curved surface Sr is formed linearly in the lateral direction in order to facilitate
understanding and explanation, the curved surface Sr is further divided into a plurality of upper
and lower surfaces. By overlapping in a step-like manner, the radiation angle αt can be spread in
a balanced manner vertically and horizontally (Srn (n = 1, 2,...)). In addition, the radiation angle
αt of the sound wave from the virtual sound source can be increased in the vertical direction of
the listener 81 (upper and lower directions by increasing the elliptical arc Co, which is the basis
of rotation, in the upper and lower directions (= larger angle viewed from the focal point F1).
Direction) can be extended.
[0066]
As a result, in the sound source configuration device 10 according to the present embodiment, as
in the first embodiment, even if the virtual sound source is relatively close to the listener 81, both
ears enter the radiation angle αt, and stable sound source localization Can be heard as a natural
sound. Also, since the sound wave can be made to sharply diverge in the vicinity of the listener
81 and then can be made to diverge rapidly, the sound pressure will drop sharply as it gets away
from the virtual sound source position (near the focal point F1). Therefore, according to the
present embodiment, it is possible to provide a sound source configuration apparatus 10 suitable
for a personal communication sound source device or the like which configures a virtual sound
09-05-2019
21
source in a space and facilitates the limited use of the sound source by a specific individual. Can.
[0067]
Embodiment 3 In this embodiment, in the embodiment 2, the transducers Tn (n = 1, 2,... So that
the amount of the reflected wave 62 on the curved surface Sr of the sound wave 61 emitted from
the front end abuts on the transducer itself is reduced. And the incident position of the sound
wave 61 on the curved surface Sr. That is, as shown in FIG. 7, in the apparatus 10 of this
example, the transducers Tn (n = 1, 2,... ) Is in the vicinity of the second focal point F2 of the
ellipse Eo inscribed in the reflection surface Sr to which the sound wave 61 is directed, and the
transducers Tn (n = 1, 2,...) The radiation direction of the sound wave 61 emitted from) is on a
line inclined with respect to an axis connecting the two focal points F1 and F2 of the ellipse Eo
inscribed in the reflecting surface Sr.
[0068]
In this example, as shown in FIG. 8, a method of forming the curved surface Sr is shown by
rotating the spheroid Er and thereby rotating the elliptic arc Co of the ellipse Eo circumscribed to
the spheroid Er. ing. This is because there is no difference between rotating the elliptic arc Co of
the ellipse Eo by rotating the spheroid Er and rotating the plane including the ellipse Eo and
rotating the elliptic arc Co. In FIG. 8, an arc 52 shows a locus drawn by the second focal point F2
of the ellipse Eo, an arc 53 shows a locus drawn by one end point of the elliptic arc Co, and an
arc 54 shows a locus drawn by one end point of the elliptic arc Co.
[0069]
As shown in FIG. 7, if there is a radiation wave (primary wave) 61 on the axis connecting the two
focal points F1 and F2 of the ellipse Eo, the reflected wave (secondary wave) 62 passes the focal
point F1 and the reflected wave (secondary wave) The second wave 62 is a transducer Tn (n = 1,
2,...) Collide with or scatter). However, the reflected wave (secondary wave) 62 is a transducer Tn
(n = 1, 2,...) By deviating the radiation direction of the radiation wave (primary wave) 61 from the
axis connecting the focal points F1 and F2. ) It does not collide with itself or scatter. Thus, the
emitted sound waves 61 are effectively utilized and demodulated into audible sound waves.
Others are the same as in the second embodiment.
09-05-2019
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[0070]
As described above, according to the present invention, the radiation angle α of the sound from
the virtual sound source is broadened to stabilize the sound source localization by binaural
hearing and the convergence unnecessary for listening. It is possible to provide a sound source
configuration device suitable for a personal communication sound source device or the like,
which can sharply reduce the sound pressure in an area far from the point.
09-05-2019
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