close

Вход

Забыли?

вход по аккаунту

?

DESCRIPTION JP2012239023

код для вставкиСкачать
Patent Translate
Powered by EPO and Google
Notice
This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or
financial decisions, should not be based on machine-translation output.
DESCRIPTION JP2012239023
[Problem] To provide a parametric speaker which is kind to the human ear, efficient, and capable
of eliminating the lack of bass by promoting the demodulation of the bass. An ultrasonic wave
generation unit 4 of a parametric speaker 1 irradiates an ultrasonic wave toward a film member
3 stretched in a state where a tension is applied to an opening 2 a of a housing 2. The reflected
ultrasonic wave is emitted toward the target direction. Most of the ultrasonic waves reflected by
the tensioned membrane member 3 are directed toward the target direction without attenuation.
On the other hand, a part of ultrasonic waves 3 vibrate the film member 3 among the ultrasonic
waves that hit the film member 3. Since the film member 3 vibrates while receiving the viscosity
of air, it is possible to forcibly demodulate a low-pitched sound delayed in demodulation by the
vibration of the film member 3. This is kind to the human ear, efficient and can eliminate the lack
of bass. [Selected figure] Figure 1
パラメトリックスピーカ
[0001]
According to the present invention, an ultrasonic wave in which audible sound is ultrasonically
modulated is generated from an ultrasonic wave generator (specifically, an ultrasonic wave
generator that generates ultrasonic waves in an ultrasonic speaker) and is separated from the
ultrasonic wave generator The present invention relates to a parametric speaker in which an
audible sound is reproduced in the air, for example, (i) a vehicle presence notification device
notifying the presence of a vehicle to the surrounding by a notification sound, (ii) An alerting
device that informs the driver with a notification sound by using a notification sound, (iii) An
audio device that provides audio voice such as music or radio voice to multiple passengers
boarding a vehicle, (iv) Audio voice is limited to a specific vehicle occupant The present invention
relates to a technique suitable for use in a personal audio device, etc.
11-04-2019
1
[0002]
The waveform signal (electric signal) of the audible sound is ultrasonically modulated and
irradiated from the ultrasonic generator into the air, and the modulation component contained in
the ultrasonic wave (sound wave that can not be heard by the ear) is self-demodulated in the air
on the way There is known a parametric speaker that generates an audible sound (informing
sound) at a location apart from the ultrasonic wave generation unit.
[0003]
Since this parametric speaker is a technology using highly directional (straight) ultrasonic waves,
audible sound can be generated only in an arbitrary direction.
For this reason, it is possible to generate a notification sound (such as a pseudo engine sound)
only in a specific direction (such as the front) of the vehicle, which is suitable for use in the
vehicle presence notification device.
Alternatively, a warning sound (such as voice) can be generated only for the driver among the
occupants of the vehicle, which is suitable for use as a device for alerting the driver. Furthermore,
audio sound (music, radio sound, etc.) can be given to a plurality of occupants, or audio sound
can be generated only for a specific occupant of the plurality of occupants. It is suitable for use in
an apparatus.
[0004]
However, since the parametric speaker is to self-demodulate the ultrasonic wave using the
viscosity (non-linearity) of air, the lower the frequency is, the more it is necessary to be away
from the ultrasonic wave generator to perform the self-demodulation. That is, at a distance close
to the ultrasonic wave generation unit, the degree of demodulation of the bass is small and the
bass is small.
[0005]
11-04-2019
2
As a technique for solving the above-mentioned problems, the technique disclosed in Patent
Document 1 is known. The technology of Patent Document 1 flattens the frequency by actively
attenuating the high-pitched sound side by using the fact that the high-pitched sound with high
demodulation speed is large although the low-pitched sound is small when the distance of the
ultrasonic wave generation unit is short. It is a technology to achieve original sound reproduction
to make the timbre close to the input signal. Specifically, the technique of Patent Document 1 is
to reflect the ultrasonic wave emitted from the ultrasonic wave generation unit toward a person
by a reflector having a sound wave attenuating function, and the high sound side of the reflector
is positively Attenuation is a technology for achieving frequency flattening.
[0006]
However, since the technology of Patent Document 1 is a technology for attenuating the highpitched sound side by the reflector and matching the sound pressure on the high-pitched sound
side to the low-pitched sound side, the sound pressure reaching the human ear is Naturally it will
be small. In order to restore the sound pressure reaching the human ear before attenuation, it is
necessary to increase the sound pressure of the ultrasonic wave emitted from the ultrasonic
wave generator. Therefore, the technology of Patent Document 1 consumes a large amount of
power and is inefficient. Further, since the technology of Patent Document 1 needs to increase
the sound pressure generated by the ultrasonic wave, the ultrasonic wave (high sound pressure
ultrasonic wave) that is not attenuated is a person's ear when a defect occurs in the reflector due
to some factor. There is a concern that the ear may be adversely affected.
[0007]
Japanese Patent Application Publication No. 2003-163986
[0008]
The present invention has been made in view of the above problems, and an object thereof is to
provide a parametric speaker which is kind to human ears, is efficient, and can eliminate the
shortage of the bass by promoting the demodulation of the bass. .
[0009]
[Means of claim 1] The parametric speaker according to claim 1 is for reflecting the ultrasonic
11-04-2019
3
wave irradiated from the ultrasonic wave generation unit by a film member (a film body
stretched in a tensioned state), The reflected ultrasonic wave is directed in the direction (any
reflection direction depending on the inclination angle of the film member with respect to the
ultrasonic wave generation unit).
Since the ultrasonic waves have high rectilinearity and excellent reflectivity, most of the
ultrasonic waves reflected by the film member to which tension is applied are emitted in the
target direction without being attenuated by the film member.
[0010]
On the other hand, a part of ultrasonic waves of the ultrasonic waves striking the membrane
member vibrate the membrane member.
Since the film member vibrates while receiving the viscosity (non-linearity) of air, the modulation
component of the ultrasonic wave that vibrates the film member is demodulated into audible
sound by the vibration of the film member. As a result, the low frequency component that delays
the demodulation can be generated by the vibration of the film member.
[0011]
As described above, most of the ultrasonic waves are reflected by the film member without being
attenuated by the film member and emitted in the target direction, so that the efficiency is not
deteriorated. In addition, since the lack of bass is compensated by demodulation due to the
vibration of the film member, the lack of bass can be eliminated. Furthermore, since it is not
necessary to increase the sound pressure of ultrasonic waves as in the prior art, there is no
problem that ultrasonic waves of increased sound pressure reach human ears. That is, the
parametric speaker according to claim 1 can accelerate the demodulation of the bass to be gentle
to the human ear, efficiently, and eliminate the shortage of the bass.
[0012]
[Means of claim 2] The parametric speaker according to claim 2 irradiates the film member with
the ultrasonic wave emitted from the ultrasonic wave generation unit, and a part of the ultrasonic
waves generated by the ultrasonic wave generation unit Is transmitted through the ultrasonic
11-04-2019
4
wave passing hole provided in the membrane member toward the target direction (any direction
in which the ultrasonic wave generator is directed).
[0013]
On the other hand, a part of ultrasonic waves of the ultrasonic waves striking the membrane
member vibrate the membrane member.
Since the film member vibrates while receiving the viscosity (non-linearity) of air, the modulation
component of the ultrasonic wave that vibrates the film member is demodulated into audible
sound by the vibration of the film member. As a result, the low frequency component that delays
the demodulation can be generated by the vibration of the film member.
[0014]
In this way, part of the ultrasonic waves pass through the ultrasonic wave passage holes and are
emitted in the target direction, so that the efficiency does not deteriorate. In addition, since the
lack of bass is compensated by demodulation due to the vibration of the film member, the lack of
bass can be eliminated. Furthermore, since it is not necessary to increase the sound pressure of
ultrasonic waves as in the prior art, there is no problem that ultrasonic waves of increased sound
pressure reach human ears. That is, the parametric speaker of the second aspect promotes the
demodulation of the bass as in the case of the means of the first aspect, can be kind to human
ears, is efficient, and can eliminate the shortage of the bass.
[0015]
[Means of Claim 3] The membrane member of Claim 3 is provided at an opening of a housing
(container) in which a volume chamber is formed. Since air in the volume chamber exerts a
dumping action (action to enhance the non-linearity) to damp the vibration of the film member,
the demodulation efficiency due to the vibration of the film member can be enhanced.
[0016]
11-04-2019
5
[Means of Claim 4] The volume chamber of Claim 4 constitutes a closed space. Since the volume
chamber forms a closed space, it is possible to enhance the dumping action for damping the
vibration of the film member and to further enhance the demodulation efficiency due to the
vibration of the film member.
[0017]
[Means for claim 5] A parametric speaker according to claim 5 is used for a vehicle presence
notification device for generating a notification sound to the outside of a vehicle to notify the
presence of a vehicle. For this reason, the lack of bass of the reproduced sound of the parametric
speaker in the vicinity of the vehicle can be eliminated.
[0018]
It is explanatory drawing of the parametric speaker which reflects an ultrasonic wave by a film |
membrane member (Embodiment 1). It is explanatory drawing of a parametric speaker which
applies an ultrasonic wave to a film | membrane member, and allows some ultrasonic waves to
pass through (Embodiment 2). It is a vehicle mounting view of an ultrasonic speaker and the
horn for vehicles (Example 1). It is a top view of a membrane member (example 1). It is the
schematic of a vehicle presence alerting | reporting apparatus (Example 1). It is principle
explanatory drawing of a parametric speaker (Example 1).
[0019]
Embodiment 1 Embodiment 1 will be described with reference to FIG. The parametric speaker 1
according to the first embodiment includes: a membrane member 3 stretched in a state in which
a tension is applied to an opening 2a of a housing 2 in which a volume chamber is formed; An
ultrasonic wave generation unit 4 for converting an acoustic wave signal (electric signal) into an
ultrasonic wave (compression wave of air) and directing the ultrasonic wave toward the film
member 3; An ultrasonic wave modulation means 5 for generating an ultrasonic wave signal; an
ultrasonic wave drive means (amplifier means) 6 for driving an ultrasonic wave generation unit 4
by an ultrasonic wave signal generated by the ultrasonic wave modulation means 5; The
ultrasonic wave reflected by 3 is emitted in the air (target direction: for example, the front of a
vehicle).
11-04-2019
6
[0020]
Most of the ultrasonic waves reflected by the tensioned membrane member 3 are emitted toward
the target direction without being attenuated by the membrane member 3. On the other hand, a
part of ultrasonic waves (ultrasound relating to the natural frequency of the film member 3) of
the ultrasonic waves striking the film member 3 vibrate the film member 3. At that time, since
the film member 3 vibrates by receiving the viscosity of air, the modulation component of the
ultrasonic wave that vibrates the film member 3 is demodulated into an audible sound. As a
result, the low frequency component that delays the demodulation can be generated by the
vibration of the film member 3.
[0021]
As described above, most of the ultrasonic waves are reflected by the film member 3 without
being attenuated and emitted in the target direction, so that the efficiency is not deteriorated. In
addition, it is possible to compensate for the lack of bass by demodulating the bass due to the
vibration of the film member 3. Furthermore, since it is not necessary to increase the sound
pressure of ultrasonic waves as in the prior art, there is no problem that ultrasonic waves of
increased sound pressure reach human ears. That is, the parametric speaker 1 according to the
first embodiment promotes the demodulation of the bass, is kind to the human ear, is efficient,
and can eliminate the shortage of the bass.
[0022]
Second Embodiment A second embodiment will be described with reference to FIG. The
parametric speaker 1 according to the second embodiment includes: a membrane member 3
stretched in a state in which a tension is applied to the opening 2a of the housing 2 in which a
volume chamber is formed; An ultrasonic wave generation unit 4 for converting an acoustic wave
signal (electric signal) into an ultrasonic wave (compression wave of air) and directing the
ultrasonic wave toward the film member 3; The ultrasonic wave modulation unit 5 generates an
acoustic wave signal, and the ultrasonic wave drive unit (amplifier unit) 6 that drives the
ultrasonic wave generation unit 4 by the ultrasonic wave signal generated by the ultrasonic wave
modulation unit 5. The film member 3 is provided with an ultrasonic wave passing hole 3a for
passing a part (including a majority) of the ultrasonic waves generated by the ultrasonic wave
11-04-2019
7
generating unit 4, and the ultrasonic wave passing through the ultrasonic wave passing hole 3a
is in the air. (Objective direction: For example, it is made to irradiate in front of a vehicle etc.).
[0023]
The ultrasonic wave that has passed through the ultrasonic wave passage hole 3 a is emitted
toward the target direction without being attenuated by the film member 3. On the other hand, a
part of ultrasonic waves (ultrasound relating to the natural frequency of the film member 3) of
the ultrasonic waves striking the film member 3 vibrate the film member 3. Since the film
member 3 vibrates while receiving the viscosity (nonlinearity) of air, the modulation component
of the ultrasonic wave that vibrates the film member 3 is demodulated into an audible sound by
the vibration of the film member 3. As a result, the low frequency component that delays the
demodulation can be generated by the vibration of the film member 3.
[0024]
As described above, a part of the ultrasonic waves pass through the ultrasonic wave passage
holes 3a and are emitted in the target direction, so that the efficiency does not deteriorate. In
addition, it is possible to compensate for the lack of bass by demodulating the bass due to the
vibration of the film member 3. Furthermore, since it is not necessary to increase the sound
pressure of ultrasonic waves as in the prior art, there is no problem that ultrasonic waves of
increased sound pressure reach human ears. That is, the parametric speaker 1 according to the
second embodiment promotes the demodulation of the bass, is kind to the human ear, is efficient,
and can eliminate the shortage of the bass.
[0025]
A specific example (embodiment) to which the present invention is applied will be described
below with reference to the drawings. The embodiment described below is a specific example,
and it goes without saying that the present invention is not limited to the embodiment. In the
following examples, the same reference numerals as those in the above-mentioned "embodiment
of the invention" indicate the same functional objects.
[0026]
11-04-2019
8
Example 1 Example 1 will be described with reference to FIGS. 3 to 6. This embodiment is an
application of the second embodiment described above to the parametric speaker 1 mounted on
a vehicle presence notification device, and the details will be described below.
[0027]
The vehicle presence notification device notifies presence of a vehicle by a notification sound (for
example, a pseudo engine sound: not limited), and for example, a vehicle (electric vehicle, fuel cell
automobile) not equipped with an engine (internal combustion engine) Etc.), vehicles that may
stop the engine while driving and stopping (such as hybrid vehicles), vehicles that may stop the
engine while stopping (such as idle stop vehicles), or even engine vehicles It is to be installed in
the motor car and the like that the running noise is quiet.
[0028]
This vehicle presence notification device:-A parametric speaker 1 emitting ultrasonic waves
formed by ultrasonically modulating a frequency signal forming a notification sound, and
emitting it-A dynamic signal emitting notification sound in the audible band directly to the
outside of the vehicle A vehicle horn 11 used as a speaker, and a control circuit 12 that performs
operation control of the parametric speaker 1 and the vehicle horn 11 are configured.
[0029]
(Description of the parametric speaker 1) The ultrasonic speaker 7 which generates an ultrasonic
wave in the parametric speaker 1 generates an air vibration of a frequency (20 kHz or more)
higher than the human audible band, It is mounted on the vehicle so as to release it toward the
vehicle.
Specifically, the ultrasonic speaker 7 of this embodiment is provided on the front surface of the
vehicle horn 11 (the surface facing the front of the vehicle when the vehicle is mounted: for
example, a spiral horn), and as shown in FIG. The vehicle horn 11 is attached between the heat
exchanger 14 and the heat exchanger 15 (a radiator, a heat exchanger for air conditioning, etc.),
so that the ultrasonic speaker 7 is a vehicle with the ultrasonic radiation direction directed to the
front of the vehicle. Will be mounted on.
11-04-2019
9
[0030]
The ultrasonic speaker 7 of this embodiment comprises at least: an ultrasonic wave generator 4
for generating an ultrasonic wave; and a housing 2 for housing the ultrasonic wave generator 4.
[0031]
The ultrasonic wave generation unit 4 generates an ultrasonic wave formed by compression
wave of air by converting an ultrasonic wave signal (electric signal of ultrasonic wave frequency
obtained by ultrasonically modulating audible sound) given from the ultrasonic wave modulation
means 5 into ultrasonic wave. The plurality of ultrasonic wave generating elements 16 are
provided.
The plurality of ultrasonic wave generating elements 16 are collectively disposed on a support
plate 17 fixedly disposed inside the housing 2 and mounted as a speaker array.
Note that a specific example of the ultrasonic wave generation element 16 is a small-sized
piezoelectric speaker suitable for generating an ultrasonic wave, and a piezoelectric element
(piezoelectric element) that undergoes expansion / contraction displacement according to an
applied voltage (charge / discharge); The diaphragm is configured to be driven by expansion and
contraction of the element to generate compression waves in air.
[0032]
The housing 2 may be provided integrally with the member forming the vehicle horn 11 or may
be provided separately and attached to the vehicle horn 11. Specifically, the housing 2 is
provided with a volume chamber for housing the ultrasonic wave generator 4 inside, and the
opening 2a for emitting the ultrasonic wave emitted from each ultrasonic wave generating
element 16 toward the front of the vehicle (Ultrasonic radiation port) is provided. In addition, the
housing 2 is provided in the substantially airtight container except the opening part 2a.
[0033]
The opening 2 a of the housing 2 is provided with waterproofing means for preventing rainwater
11-04-2019
10
from intruding into the mounting portion of each ultrasonic wave generating element 16. As an
example of this waterproofing means, in this embodiment, an ultrasonic permeable waterproof
sheet 18 covering the opening 2a and a louver 19 disposed on the front surface of the
waterproof sheet 18 are provided.
[0034]
The louver 19 is used to reduce the possibility of rainwater reaching the waterproof sheet 18 as
much as possible. The louver 19 is a gutter that has an elongated slat arranged horizontally with
a gap. As shown in FIG. 3, the louver 19 is provided so as to be inclined approximately 45 ° with
respect to the horizontal direction of the vehicle. As a result, the ultrasonic waves emitted from
the respective ultrasonic wave generating elements 16 turn downward at the inner surface of the
louver 19, and turn forward again at the outer surface of the lower louver 19, and consequently
the front of the vehicle It is emitted towards the
[0035]
Further, the opening 2 a of the housing 2 is provided with the film member 3 stretched in a state
in which a tension is applied. The film member 3 of this embodiment is disposed on the front
surface of the waterproof sheet 18, and is provided with a small gap (for example, a gap of about
1 to 5 mm) between the waterproof sheet 18 and the film. In addition, unlike FIG. 3, the film
member 3 may be provided inside the waterproof sheet 18. The film member 3 is a film material
similar to that of a percussion film (drum film etc.) of a membrane sounding instrument (drums
etc.), and is provided by a material (resin film etc.) excellent in ultrasonic wave reflectivity
without fluff on the surface. And has a predetermined natural frequency according to the tension
applied, the membrane area, and the like.
[0036]
Further, as shown in FIG. 4, a part of the ultrasonic wave generated by the ultrasonic wave
generator 4 (for example, 70 to 90% of the ultrasonic wave generated by the ultrasonic wave
generator 4) is allowed to pass through the film member 3 A large number of ultrasonic wave
passage holes 3a are provided. Although FIG. 4 shows an example in which the ultrasonic wave
passage holes 3a are provided substantially equally to the film member 3, it is not limited and the
arrangement of the ultrasonic wave passage holes 3a may be biased. Further, although FIG. 4
11-04-2019
11
shows an example in which the ultrasonic wave passage holes 3a having the same hole diameter
are provided in the multiple membrane members 3, ultrasonic wave passage holes 3a having
different hole diameters may be provided in the film member 3. Alternatively, as another specific
example of the ultrasonic wave passage hole 3a, one or more large holes may be provided.
[0037]
(Description of Vehicle Horn 11) As described above, the vehicle horn 11 is fixedly disposed
between the front grille 14 and the heat exchanger 15, and a horn switch (for example, a horn
button of a steering wheel) by an occupant Is a well-known electromagnetic horn that generates
an audible alarm when it is operated. The vehicle horn 11 is mounted on the vehicle such that
the opening of the spiral horn faces downward (road surface) so that the notification sound
generated from the vehicle horn 11 reaches the periphery of the vehicle substantially equally. It
is.
[0038]
(Description of Control Circuit 12) The control circuit 12 is configured using a microcomputer
chip 21 (abbreviated to a microcomputer chip) as shown in FIG. 3, and, for example, as shown in
FIG. 12 is arranged inside the vehicle horn 11 (specifically, inside the horn housing), but is not
limited thereto.
[0039]
The control circuit 12 will be specifically described with reference to FIG.
The control circuit 12 is connected to a power supply (battery) and is given a horn switch signal
and a vehicle speed signal (for example, a vehicle speed pulse signal etc.) (a) (B) When the
determination means 22 determines that "the driving state of the vehicle conforms to the
condition for generating the notification sound", "the notification sound is (C) ultrasonic
modulation means 5 for modulating the "frequency signal forming the notification sound" output
from the notification sound generation means 23 to an ultrasonic frequency; (D) ultrasonic drive
means 6 for driving the ultrasonic speaker 7 (a plurality of ultrasonic wave generation elements
16 forming the ultrasonic wave generation unit 4), and (e) horn drive means 24 for driving the
vehicle horn 11; Prepare. Hereinafter, each means of the above (a) to (e) mounted on the control
circuit 12 will be described.
11-04-2019
12
[0040]
(Description of Determination Means 22) The determination means 22 determines that the
driving state of the vehicle conforms to the generation condition of the notification sound when,
for example, the vehicle travels at a vehicle speed equal to or lower than a predetermined speed
(for example, 20 km / h). The notification sound generation means 23 is operated (this is a
specific example for describing the embodiment and is not limited).
[0041]
(Description of Notification Sound Generation Means 23) The notification sound generation
means 23 is provided by the notification sound generation program (sound software), and when
the operation instruction is given from the determination means 22, the digital signal Audio
signals of the audio frequency: for example, electric signals that make a pseudo engine sound).
[0042]
(Description of Ultrasonic Modulating Unit 5) The ultrasonic modulating unit 5 performs
ultrasonic modulation of “a frequency signal (an example of an audible sound signal) forming
the notification sound” output from the notification sound generating unit 23.
As a specific example of the ultrasonic modulation means 5, in this embodiment, the output
signal of the notification sound generation means 23 is modulated to a predetermined "amplitude
change (increase or decrease change of voltage) at ultrasonic frequency (for example, 25 kHz
etc.)" AM modulation (amplitude modulation) is used.
The ultrasonic modulation means 5 is not limited to AM modulation, and PWM modulation that
modulates the output signal of the notification sound generation means 23 to a predetermined
"pulse width change at ultrasonic frequency (pulse generation time width)" Other ultrasound
modulation techniques may be used, such as (pulse width modulation).
[0043]
A specific example of the ultrasonic wave modulation by the ultrasonic wave modulation means 5
11-04-2019
13
will be described with reference to FIG. For example, it is assumed that the "frequency signal
forming a notification sound" input to the ultrasonic modulation means 5 is the voltage change
shown in FIG. 6A (note that in the figure, a waveform of a single frequency to aid understanding).
Show). On the other hand, it is assumed that the ultrasonic oscillator mounted on the control
circuit 12 oscillates at the ultrasonic frequency shown in FIG.
[0044]
Then, as shown in FIG. 6C, (i) the ultrasonic modulation means 5 increases the amplitude of the
voltage due to the ultrasonic vibration as the signal voltage of the frequency forming “the
frequency signal forming the notification sound” increases. (Ii) As the signal voltage of the
frequency forming “the frequency signal forming the notification sound” becomes smaller, the
amplitude of the voltage due to the ultrasonic vibration is reduced. In this way, the ultrasonic
modulation means 5 modulates the "frequency signal forming the notification sound" output
from the notification sound generation means 23 into "amplitude change of oscillation voltage"
of the ultrasonic frequency.
[0045]
(Description of Ultrasonic Driving Means 6) The ultrasonic driving means 6 drives the ultrasonic
speaker 7 based on the ultrasonic signal modulated by the ultrasonic modulation means 5 (for
example, a push-pull class B amplifier, Alternatively, it is a push-pull class D amplifier or the like),
and by modulating the applied voltage (charging / discharging state) of each ultrasonic wave
generating element 16, the “frequency signal forming notification sound” is modulated from
each ultrasonic wave generating element 16 It generates ultrasonic waves.
[0046]
(Description of Horn Driving Means 24) The horn driving means 24 operates (i) the vehicle horn
11 as a dynamic speaker while the alarm sound generation means 23 generates the "frequency
signal forming the alarm sound". A power amplifier function that amplifies the frequency signal
that forms the notification sound and generates an audible notification sound from the vehicle
horn 11; (ii) applies battery voltage to the vehicle horn 11 while the horn switch is ON And a
continuous ON function that generates an alarm sound from the vehicle horn 11.
Note that "ON of horn switch" has priority over "instruction to generate alarm sound", and it is
11-04-2019
14
provided so that an alarm sound is always generated from the vehicle horn 11 when the horn
switch is turned on.
[0047]
(Operation of Vehicle Presence Informing Device) When the driving state of the vehicle conforms
to the generation condition of the notification sound, the notification sound generation means 23
outputs “the frequency signal that forms the notification sound”, and the ultrasonic speaker 7
As shown in), an ultrasonic wave (a sound wave that can not be heard) obtained by modulating
the “frequency signal that constitutes a notification sound” is emitted toward the front of the
vehicle. Then, as shown in FIG. 6D, as the ultrasonic wave propagates in the air, the ultrasonic
wave having a short wavelength is distorted and blunted due to the viscosity of the air or the like.
As a result, as shown in FIG. 6 (e), the amplitude component contained in the ultrasonic wave is
self-demodulated in the air on the way of propagation, and as a result, the "announcement sound"
is reproduced in front of the vehicle. On the other hand, when the notification sound generation
means 23 outputs the "frequency signal forming the notification sound", the "information sound"
of the audible sound is directly emitted from the vehicle horn 11 around the vehicle.
[0048]
(Effects of the First Embodiment) A part of ultrasonic waves (many ultrasonic waves) emitted
from the ultrasonic wave generator 4 (a plurality of ultrasonic wave generating elements 16)
pass through the ultrasonic wave passing hole 3a to the front of the vehicle. Released towards.
On the other hand, a part of the ultrasonic waves 3 (the ultrasonic waves directly or indirectly
related to the natural frequency of the film member 3) among the ultrasonic waves striking the
film member 3 vibrate the film member 3. Since the film member 3 vibrates while receiving the
viscosity (nonlinearity) of air, the modulation component of the ultrasonic wave that vibrates the
film member 3 is demodulated into an audible sound by the vibration of the film member 3. As a
result, the low frequency component that delays the demodulation can be generated by the
vibration of the film member 3.
[0049]
The demodulated sound of the ultrasonic wave that has passed through the ultrasonic wave
passage hole 3a is delayed in the demodulation of the bass in a range close to the vehicle, and
11-04-2019
15
becomes a notification sound with a small bass. However, since the parametric speaker 1 of this
embodiment compensates for the lack of bass by demodulation due to the vibration of the film
member 3, the lack of bass of the notification sound can be resolved even in a range close to the
vehicle. That is, even if it is near the vehicle, a realistic pseudo engine sound etc. can be
generated.
[0050]
As described above, since a part (many) of the ultrasonic waves pass through the ultrasonic wave
passage holes 3a and are radiated to the front of the vehicle, it is not necessary to increase the
sound pressure of the ultrasonic waves as in the prior art. Further, due to the demodulation of
the bass using the vibration of the film member 3, it is possible to compensate for the shortage of
the bass of the notification sound. Furthermore, since it is not necessary to increase the sound
pressure of ultrasonic waves as in the prior art, there is no concern that ultrasonic waves of
increased sound pressure reach the human ear. That is, the parametric speaker 1 mounted on the
vehicle presence notifying apparatus of this embodiment promotes the demodulation of the bass,
is kind to human ears, is efficient, and can eliminate the shortage of the bass.
[0051]
Although the example which applies Embodiment 2 to a vehicle presence alerting apparatus was
shown in said Example, you may apply Embodiment 1 to a vehicle presence alerting apparatus.
That is, the ultrasonic speaker 7 is provided which directs the ultrasonic wave emitted from the
ultrasonic wave generator 4 to the front of the vehicle by reflecting it on the film member 3 (a
film material to which the ultrasonic wave passing hole 3a is not opened is given tension). It may
be mounted on a vehicle.
[0052]
Although the example which applies this invention to the parametric speaker 1 of a vehicle
presence alerting system was shown in said Example, it is not limited, For example, it is the
driving | running | working state which a vehicle starts when (i) depresses an accelerator. The
invention may be applied to the parametric speaker 1 using the parametric speaker 1 as an
alerting device for notifying the driver by a notification sound (such as a pseudo engine sound),
and (ii) to a plurality of occupants who board the vehicle Alternatively, the parametric speaker 1
may be used as an audio device for providing audio voice such as music or radio voice, and the
present invention may be applied to the parametric speaker 1. (iii) Personal audio voice is given
11-04-2019
16
only to a specific vehicle occupant The parametric speaker 1 is used as an audio device and its
parametric speed is The present invention may be applied to 1.
[0053]
DESCRIPTION OF SYMBOLS 1 parametric speaker 2 housing 2a opening part 3 film | membrane
member 3a ultrasonic wave passage hole 4 ultrasonic wave generation part 5 ultrasonic wave
modulation means 6 ultrasonic wave drive means 7 ultrasonic wave speaker
11-04-2019
17
Документ
Категория
Без категории
Просмотров
0
Размер файла
30 Кб
Теги
description, jp2012239023
1/--страниц
Пожаловаться на содержимое документа