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JP2013115609

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DESCRIPTION JP2013115609
Abstract: [Problem] An object of the present invention is to provide a non-directional speaker
having a plurality of speaker units capable of reproducing audio in different reproduction bands.
Another object of the present invention is to provide a reproduction band adjustment method
capable of easily adjusting the reproduction band of the speaker unit of the speaker. A speaker
(1) includes a plurality of speaker parts (2, 3) each having a different reproduction band of
sound. The speaker portion 2 has a tubular vibrating portion 20 having a dielectric layer 200
made of elastomer or resin, and a plurality of electrode layers 201 and 202 disposed on the
inner and outer peripheral surfaces of the dielectric layer 200. The speaker unit 3 has a tubular
vibrating unit 30 having a dielectric layer 300 made of elastomer or resin and a plurality of
electrode layers 301 and 302 disposed on the inner and outer peripheral surfaces of the
dielectric layer 300. [Selected figure] Figure 2
Speaker and playback band adjustment method
[0001]
The present invention relates to a speaker having a plurality of speaker units and a method of
adjusting a reproduction band of the speaker unit.
[0002]
Patent Document 1 discloses an omnidirectional speaker.
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1
The speaker described in the same document has a cylindrical shape. Moreover, the speaker
described in the same document includes a vibrator and a pair of electrodes. The vibrator is made
of piezoelectric ceramic. The pair of electrodes is disposed on the inner circumferential surface
and the outer circumferential surface of the vibrator.
[0003]
Similar to Patent Document 1, Patent Document 2 discloses a nondirectional speaker. The
speaker described in the same document has a cylindrical shape. Moreover, the speaker
described in the same document includes a base layer and a pair of electrodes. The base layer is
made of an elastomeric film. The pair of electrodes are disposed on the inner and outer
peripheral surfaces of the base layer.
[0004]
JP-A-9-327092 JP-A-2009-272978
[0005]
According to the speakers described in Patent Documents 1 and 2, sound can be reproduced
toward all directions in the horizontal plane.
However, these speakers can not reproduce sound in a plurality of reproduction bands (for
example, high frequency band and low frequency band). For this reason, in the case of playing
back audio in a plurality of playback bands, it is necessary to arrange a dedicated speaker for
each playback band. Therefore, the installation space of the speaker is increased.
[0006]
The speaker of the present invention is completed in view of the above-mentioned subject. An
object of the present invention is to provide a non-directional speaker having a plurality of
speaker units capable of reproducing audio in different reproduction bands. Another object of
the present invention is to provide a reproduction band adjustment method capable of easily
adjusting the reproduction band of the speaker unit of the speaker.
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[0007]
(1) In order to solve the above problems, the speaker of the present invention has a tubular
shape having a dielectric layer made of elastomer or resin, and a plurality of electrode layers
disposed on the inner peripheral surface and the outer peripheral surface of the dielectric layer.
And a plurality of speaker units each having a different audio reproduction band.
[0008]
Here, "made of elastomer or resin" means that the substrate of the dielectric layer is made of
elastomer or resin.
That is, the dielectric layer may contain, in addition to the elastomer or resin, other components
such as additives. "Elastomer" also includes rubber and thermoplastic elastomers. The term
“cylindrical” refers to a bottomless cylindrical (a cylindrical shape having no bottom at both
axial ends) or a bottomed cylindrical (a cylindrical having a bottom at least one of the axial ends).
Also, “different reproduction bands of sound” means, in the frequency distribution of sound
pressure levels, the case where the adjacent reproduction bands are completely separated, as
well as the case where the adjacent reproduction bands partially overlap. Including.
[0009]
The speaker of the present invention includes a plurality of speaker units. The speaker portion
includes a radially outer electrode layer, a dielectric layer, and a radially inner electrode layer as
viewed from the dielectric layer. An alternating voltage based on the sound to be reproduced is
applied to the electrode layer on the outer peripheral surface of the dielectric layer and the
electrode layer on the inner peripheral surface. The radial thickness of the dielectric layer
changes in accordance with the change in electrostatic attraction between the electrode layers
based on the AC voltage. That is, the dielectric layer vibrates. Therefore, the sound is reproduced
from the speaker unit.
[0010]
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According to the speaker of the present invention, the vibrating portion has the dielectric layer
made of elastomer or resin and the electrode layer. For this reason, the speaker of the present
invention can be thinned compared to a conventional dynamic speaker unit having a permanent
magnet and a voice coil. Moreover, weight reduction is possible.
[0011]
In addition, the plurality of speaker units of the speaker of the present invention can reproduce
audio in different reproduction bands. For this reason, the speaker can be miniaturized as
compared with the case where dedicated speakers are arranged for each reproduction band such
as a high frequency band and a low frequency band. In addition, the weight of the speaker can be
reduced.
[0012]
Further, the plurality of speaker units of the speaker of the present invention each have a tubular
vibration unit. For this reason, sound can be reproduced toward all directions in the horizontal
plane. That is, the speaker of the present invention is omnidirectional.
[0013]
In addition, in the case of a speaker dedicated to the high frequency band, it is necessary to
separately provide a high pass filter in order to block the sound in the low frequency band. On
the other hand, in the case of a speaker dedicated to the low frequency band, it is necessary to
separately provide a low pass filter in order to block sound in the high frequency band. On the
other hand, according to the speaker of the present invention, it is not necessary to arrange a
filter separately. That is, there is no need to separately provide a dedicated circuit for frequency
cutoff. For this reason, the number of parts is reduced as compared to the case where dedicated
speakers are arranged for each reproduction band. Also, the circuit configuration is simple.
[0014]
As one example, by adjusting at least one of the electrical resistance of the electrode layer and
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the capacitance of the dielectric layer, it is possible to adjust the upper limit value of the
reproduction band of the speaker unit. That is, the electrode layer and the dielectric layer
constitute a low pass filter in which an electric resistance and a capacitance are connected in
series in a pseudo manner.
[0015]
Here, when the electrical resistance is R and the capacitance is C, the cutoff frequency fc of the
low pass filter is derived by the following equation (1). fc = 1 / (2πRC) equation (1) Therefore, by
adjusting the electric resistance R and the electrostatic capacitance C, it is possible to adjust the
cutoff frequency fc, that is, the upper limit value of the reproduction band. The electrical
resistance R can be adjusted by adjusting the length of the conduction path of the electrode layer,
the cross-sectional area of the conduction path (the cross-sectional area in the direction
orthogonal to the path direction), the material of the electrode layer, and the like.
[0016]
The electrical resistance R increases as the conduction path is lengthened. Conversely, shortening
the conduction path reduces the electrical resistance R. The electrical resistance R decreases as
the cross sectional area of the conduction path is increased. On the contrary, when the cross
sectional area of the conduction path is reduced, the electric resistance R is increased.
[0017]
If a material having a high conductivity is selected as a material for forming the electrode layer,
the electrical resistance R is reduced. On the other hand, when a material having low conductivity
is selected as a material of which the electrode layer is made, the electric resistance R is
increased. If the proportion of the material having high conductivity among the materials
constituting the electrode layer is increased, the electric resistance R decreases. On the other
hand, when the proportion of the material having high conductivity in the material constituting
the electrode layer is reduced, the electrical resistance R is increased.
[0018]
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The capacitance is the dielectric constant of the dielectric layer, the area of the electrode
(specifically, the area of the portion where the radially outer electrode layer and the radially
inner electrode layer overlap when viewed from the radially outer side or the radially inner side)
And the inter-electrode distance (specifically, the thickness in the radial direction of the dielectric
layer) can be adjusted. That is, assuming that the dielectric constant is ε, the electrode area is S,
and the distance between the electrodes is d, the capacitance C is derived by the following
equation (2). C = εS / d (2) When a material having a high dielectric constant ε is selected as a
material of the dielectric layer, the capacitance C is increased. On the contrary, when a material
having a low dielectric constant ε is selected as the material of the dielectric layer, the
capacitance C is reduced. When the electrode area S is increased, the capacitance C is increased.
On the contrary, when the electrode area S is reduced, the capacitance C is reduced. When the
distance d between the electrodes is increased, the capacitance C is reduced. On the contrary,
when the distance d between the electrodes is reduced, the capacitance C is increased. When the
number of laminated dielectric layers (the number of laminated electrode layers) is increased, the
capacitance C increases and the electrical resistance R decreases.
[0019]
Further, assuming that the spring constant of the vibrating portion in the surface direction
(circumferential direction and axial direction) is k and the mass of the vibrating portion is m, the
primary resonance frequency f0 is derived by the following equation (3). f0 = 1 / 2π · √ (k / m)
(3) Adjusting the primary resonance frequency f0, that is, the lower limit value of the
reproduction band, by adjusting the spring constant k in the surface direction of the vibrating
portion it can. Further, the primary resonance frequency f0 can be adjusted by adjusting the
mass m of the vibrating part.
[0020]
If a material having a high Young's modulus is selected as the material of the dielectric layer, the
spring constant is increased. For this reason, the primary resonance frequency f0 moves to the
high frequency side. On the contrary, when a material having a low Young's modulus is selected
as a material of the dielectric layer, the spring constant is reduced. For this reason, the primary
resonance frequency f0 moves to the low frequency side.
[0021]
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When a material having a high Young's modulus is selected as a material for forming the
electrode layer, the spring constant is increased. For this reason, the primary resonance
frequency f0 moves to the high frequency side. On the contrary, when a material having a low
Young's modulus is selected as a material of which the electrode layer is formed, the spring
constant is reduced. For this reason, the primary resonance frequency f0 moves to the low
frequency side.
[0022]
When the number of stacked dielectric layers (the number of stacked electrode layers) is
increased, the spring constant k is increased. On the contrary, when the number of laminated
dielectric layers (the number of laminated electrode layers) is reduced, the spring constant k
decreases. When the number of stacked dielectric layers (the number of stacked electrode layers)
is increased, the mass m of the vibrating portion is increased. On the contrary, when the number
of laminated dielectric layers (the number of laminated electrode layers) is reduced, the mass m
of the vibrating portion is reduced. As described above, k / m in equation (3) can be adjusted by
the number of laminated dielectric layers (the number of laminated electrode layers).
[0023]
When the size of the vibrating portion is increased, the mass m of the vibrating portion is
increased. For this reason, the primary resonance frequency f0 moves to the low frequency side.
Conversely, when the size of the vibrating portion is reduced, the mass m of the vibrating portion
is reduced. For this reason, the primary resonance frequency f0 moves to the high frequency
side.
[0024]
(1-1) Preferably, in the configuration of the above (1), the electrode layer is formed by applying
an electrode material which is a raw material of the electrode layer to the dielectric layer.
According to this configuration, the formation of the electrode layer and the arrangement of the
electrode layer can be performed simultaneously.
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[0025]
(1-2) Preferably, in the configuration of the above (1), the electrode layer may be bonded to the
dielectric layer. According to this configuration, the electrode layer can be firmly fixed to the
dielectric layer.
[0026]
(2) Preferably, in the configuration of the above (1), it is preferable to include a cylindrical
holding portion that contacts the inner peripheral surface of the vibrating portion. According to
this configuration, the vibrating portion can be held from the inner side in the radial direction.
For this reason, it is hard to get wrinkles in a vibration part.
[0027]
(2-1) Preferably, in the configuration of the above (2), the holding portion is preferably made of
an elastic foam made of a resin or an elastomer. The elastic foam is provided with a large number
of pores. Also, the elastic foam is flexible. Therefore, macroscopically, the vibrating portion can
be firmly held so that the vibrating portion is not wrinkled. Also, microscopically, it is difficult to
regulate fine vibrations of the vibrating portion.
[0028]
(3) Preferably, in the configuration of the above (2), a cylindrical frame portion having a
communication hole communicating with the inner peripheral surface of the holding portion in
the radial direction is preferably provided. According to this configuration, the holding portion
can be held from the inside in the radial direction by the frame portion. Moreover, the
communicating hole is arrange | positioned at a frame part. The communication holes can allow
air to pass through. Therefore, air can be allowed to pass through the anti-phase wave coming
from the inner circumferential surface of the vibrating portion without becoming an air spring
that inhibits the vibration to the outer circumferential surface of the vibrating portion. In
addition, the frame portion is an enclosure for preventing sound diffraction.
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[0029]
(4) Preferably, in any one of the configurations (1) to (3), the plurality of speaker units are a large
diameter speaker unit and a small diameter speaker unit whose outer diameter is smaller than
that of the large diameter speaker unit. It is better to have a configuration having
[0030]
The large diameter speaker portion has a large electrode area S in the above equation (2).
That is, the large diameter speaker portion has a large capacitance C. For this reason, it is easy to
set the cut-off frequency fc low in the above equation (1). Therefore, the large diameter speaker
unit is suitable for reproduction of low frequency band sound.
[0031]
On the other hand, the small diameter speaker portion has a small electrode area S in the above
equation (2). That is, the small diameter speaker portion has a small electrostatic capacitance C.
For this reason, it is easy to set the cutoff frequency fc high in the above equation (1). Therefore,
the small diameter speaker unit is suitable for reproduction of high frequency band sound.
[0032]
As described above, according to the present configuration, by using the difference in electrode
area S caused by the difference in diameter between the large diameter speaker portion and the
small diameter speaker portion, desired reproduction bands are respectively provided to the
large diameter speaker portion and the small diameter speaker portion. It can be set.
[0033]
(5) Preferably, in the configuration of any of the above (1) to (4), the dielectric layer is preferably
made of an elastomer having a Young's modulus of 1 MPa or more and 20 MPa or less.
09-05-2019
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The reason for setting the Young's modulus to 1 MPa or more is because it is difficult to set the
dielectric layer if the Young's modulus is less than 1 MPa. In addition, the reason why the
Young's modulus is set to 20 MPa or less is that the primary resonance frequency f0 is
excessively moved to the high frequency side when it exceeds 20 MPa.
[0034]
(6) In addition, in order to solve the above-mentioned problems, a reproduction band adjusting
method of the present invention is a reproduction band adjusting method of any of the abovementioned speaker portions of the speaker having any one of the above-mentioned constitutions
The cut-off frequency which is the upper limit value of the reproduction zone is adjusted by
adjusting at least one of the electric resistance of the electrode layer and the capacitance of the
dielectric layer, and the spring constant of the vibrating portion in the plane direction And by
adjusting at least one of the mass of the vibrating portion, the primary resonance frequency
which is the lower limit value of the reproduction band is adjusted.
[0035]
According to the reproduction band adjustment method of the present invention, the upper limit
value and the lower limit value of the reproduction band can be easily adjusted for each speaker
unit.
That is, the size and position of the reproduction band can be easily adjusted for each speaker
unit.
[0036]
By adjusting at least one of the electrical resistance of the electrode layer and the capacitance of
the dielectric layer, it is possible to adjust the upper limit value of the reproduction band of the
speaker unit. That is, the electrode layer and the dielectric layer constitute a low pass filter in
which an electric resistance and a capacitance are connected in series in a pseudo manner (see
the above-mentioned equation (1)).
[0037]
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10
Therefore, by adjusting the electric resistance R and the electrostatic capacitance C, it is possible
to adjust the cutoff frequency fc, that is, the upper limit value of the reproduction band. The
electrical resistance R can be adjusted by adjusting the length of the conduction path of the
electrode layer, the cross-sectional area of the conduction path (the cross-sectional area in the
direction orthogonal to the path direction), the material of the electrode layer, and the like.
[0038]
The electrical resistance R increases as the conduction path is lengthened. Conversely, shortening
the conduction path reduces the electrical resistance R. The electrical resistance R decreases as
the cross sectional area of the conduction path is increased. On the contrary, when the cross
sectional area of the conduction path is reduced, the electric resistance R is increased.
[0039]
If a material having a high conductivity is selected as a material for forming the electrode layer,
the electrical resistance R is reduced. On the other hand, when a material having low conductivity
is selected as a material of which the electrode layer is made, the electric resistance R is
increased. If the proportion of the material having high conductivity among the materials
constituting the electrode layer is increased, the electric resistance R decreases. On the other
hand, when the proportion of the material having high conductivity in the material constituting
the electrode layer is reduced, the electrical resistance R is increased.
[0040]
The capacitance is the dielectric constant of the dielectric layer, the area of the electrode
(specifically, the area of the portion where the radially outer electrode layer and the radially
inner electrode layer overlap when viewed from the radially outer side or the radially inner side)
And the inter-electrode distance (specifically, the thickness in the radial direction of the dielectric
layer) can be adjusted (see the equation (2) above).
[0041]
When a material having a high dielectric constant ε is selected as the material of the dielectric
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11
layer, the capacitance C is increased.
On the contrary, when a material having a low dielectric constant ε is selected as the material of
the dielectric layer, the capacitance C is reduced. When the electrode area S is increased, the
capacitance C is increased. On the contrary, when the electrode area S is reduced, the
capacitance C is reduced. When the distance d between the electrodes is increased, the
capacitance C is reduced. On the contrary, when the distance d between the electrodes is
reduced, the capacitance C is increased. When the number of laminated dielectric layers (the
number of laminated electrode layers) is increased, the capacitance C increases and the electrical
resistance R decreases.
[0042]
By adjusting the spring constant k in the surface direction of the vibrating portion, it is possible
to adjust the primary resonance frequency f0, that is, the lower limit value of the reproduction
band. Further, the primary resonance frequency f0 can be adjusted by adjusting the mass m of
the vibrating part (see the equation (3) above).
[0043]
If a material having a high Young's modulus is selected as the material of the dielectric layer, the
spring constant is increased. For this reason, the primary resonance frequency f0 moves to the
high frequency side. On the contrary, when a material having a low Young's modulus is selected
as a material of the dielectric layer, the spring constant is reduced. For this reason, the primary
resonance frequency f0 moves to the low frequency side.
[0044]
When a material having a high Young's modulus is selected as a material for forming the
electrode layer, the spring constant is increased. For this reason, the primary resonance
frequency f0 moves to the high frequency side. On the contrary, when a material having a low
Young's modulus is selected as a material of which the electrode layer is formed, the spring
constant is reduced. For this reason, the primary resonance frequency f0 moves to the low
frequency side.
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[0045]
When the number of stacked dielectric layers (the number of stacked electrode layers) is
increased, the spring constant k is increased. On the contrary, when the number of laminated
dielectric layers (the number of laminated electrode layers) is reduced, the spring constant k
decreases. When the number of stacked dielectric layers (the number of stacked electrode layers)
is increased, the mass m of the vibrating portion is increased. On the contrary, when the number
of laminated dielectric layers (the number of laminated electrode layers) is reduced, the mass m
of the vibrating portion is reduced. As described above, k / m in equation (3) can be adjusted by
the number of laminated dielectric layers (the number of laminated electrode layers).
[0046]
When the size of the vibrating portion is increased, the mass m of the vibrating portion is
increased. For this reason, the primary resonance frequency f0 moves to the low frequency side.
Conversely, when the size of the vibrating portion is reduced, the mass m of the vibrating portion
is reduced. For this reason, the primary resonance frequency f0 moves to the high frequency
side.
[0047]
According to the present invention, it is possible to provide a speaker having a plurality of
speaker parts that are omnidirectional and capable of reproducing audio in different
reproduction bands. Further, according to the present invention, it is possible to provide a
reproduction band adjustment method capable of easily adjusting the reproduction band of the
speaker section of the speaker.
[0048]
It is a perspective view of the speaker of a first embodiment. It is II-II direction sectional drawing
of FIG. It is an exploded perspective view of the speaker. It is a disassembled perspective view of
small diameter speaker part vicinity of the speaker. It is a disassembled perspective view of large
09-05-2019
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diameter speaker part vicinity of the speaker. It is a schematic diagram of frequency distribution
of the sound pressure level of arbitrary speaker parts. It is a schematic diagram of frequency
distribution of the sound pressure level of the speaker of 1st embodiment. It is an axial sectional
view of the speaker of 2nd embodiment.
[0049]
Hereinafter, embodiments of the speaker and the reproduction band adjustment method of the
present invention will be described.
[0050]
First Embodiment [Configuration of Speaker] First, the configuration of a speaker according to
the present embodiment will be described.
FIG. 1 shows a perspective view of the speaker of the present embodiment. FIG. 2 shows a crosssectional view taken along the line II-II in FIG. FIG. 3 shows an exploded perspective view of the
same speaker. The disassembled perspective view of the small diameter speaker part vicinity of
the speaker is shown in FIG. The disassembled perspective view of the large diameter speaker
part vicinity of the speaker is shown in FIG. In FIG. 3, the insulating shield layer 95 is shown
through. As shown in FIGS. 1 to 5, the speaker 1 according to this embodiment includes the large
diameter speaker unit 2, the small diameter speaker unit 3, the holding unit 4, the frame 7, the
circuit unit 8, and a pair of insulating shields And a layer 95.
[0051]
(Frame 7) The frame 7 includes a large diameter side frame 70, a small diameter side frame 71, a
support 72, and a base 73. The base 73 is made of resin and has a square plate shape. Inside the
base 73, electronic parts (not shown) such as an amplifier are accommodated. The support
portion 72 is made of resin and has a round bar shape. The support portion 72 protrudes
upward from the base 73.
[0052]
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The small-diameter side frame portion 71 includes a cylindrical portion 710, a pair of upper and
lower lids 711, and a large number of communication holes 712. The small diameter side frame
portion 71 has a function as an enclosure. The small diameter side frame 71 is disposed above
the base 73. The pair of upper and lower lids 711 is made of resin and has a disk shape. The pair
of upper and lower lids 711 is annularly mounted on the support column 72 at a predetermined
interval in the vertical direction (axial direction). The cylindrical portion 710 is disposed between
the pair of upper and lower lids 711. The cylindrical portion 710 is made of resin and has a
cylindrical shape. The upper and lower openings of the cylindrical portion 710 are sealed by the
pair of upper and lower lids 711. A large number of communication holes 712 are bored in the
cylindrical portion 710. The communication hole 712 penetrates the cylindrical portion 710 in
the radial direction.
[0053]
The large diameter side frame portion 70 includes a cylindrical portion 700, a pair of upper and
lower lid portions 701, and a number of communication holes 702. The large diameter side
frame portion 70 has a function as an enclosure. The large diameter side frame portion 70 is
disposed above the small diameter side frame portion 71. The configuration and the material of
the large diameter side frame portion 70 are the same as the configuration and the material of
the small diameter side frame portion 71. Further, the large diameter side frame portion 70 is
larger in diameter than the small diameter side frame portion 71. Further, the large diameter side
frame portion 70 is a longer axis than the small diameter side frame portion 71.
[0054]
(Holding part 4) The holding part 4 is provided with the large diameter side holding part 40 and
the small diameter side holding part 41. The small diameter side holding portion 41 is disposed
on the outer peripheral surface of the small diameter side frame portion 71. The small diameter
side holding portion 41 is made of urethane foam and has a cylindrical shape. The large diameter
side holding portion 40 is disposed on the outer peripheral surface of the large diameter side
frame portion 70. The large diameter side holding portion 40 is made of urethane foam and has
a cylindrical shape.
[0055]
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The small diameter speaker unit 3 includes a cylindrical vibration unit 30. The vibrating portion
30 includes a dielectric layer 300, an inner electrode layer 301, and an outer electrode layer
302. The inner electrode layer 301 and the outer electrode layer 302 are each included in the
concept of the “electrode layer” in the present invention. The vibrating portion 30 is disposed
on the outer peripheral surface of the small diameter side holding portion 41.
[0056]
The dielectric layer 300 is made of H-NBR (hydrogenated nitrile rubber), and has a cylindrical
shape and a film shape. The inner electrode layer 301 is made of a flexible conductive material in
which silver powder is filled in silicone rubber, and has a cylindrical shape and a film shape. The
inner electrode layer 301 is disposed on the inner circumferential surface of the dielectric layer
300. Specifically, the inner electrode layer 301 is formed by applying (for example, screen
printing or the like) a coating containing a flexible conductive material on the inner peripheral
surface of the dielectric layer 300.
[0057]
The outer electrode layer 302 is made of a flexible conductive material in which silver powder is
filled in silicone rubber, and has a cylindrical shape and a film shape. The outer electrode layer
302 is disposed on the outer peripheral surface of the dielectric layer 300. Specifically, the outer
electrode layer 302 is formed by applying (for example, screen printing etc.) a paint containing a
flexible conductive material on the outer peripheral surface of the dielectric layer 300. The
insulating shield layer 95 covers the outer electrode layer 302 from the radially outer side. The
insulating shield layer 95 is made of H-NBR and has a cylindrical shape and a film shape.
[0058]
As shown in FIG. 2, the area of the region P1 where the inner electrode layer 301 and the outer
electrode layer 302 overlap when viewed from the radially outer side or the radially inner side
corresponds to the electrode area S of the equation (2). Do. The reproduction band of the small
diameter speaker unit 3 is set to a high frequency band (high sound area) by a reproduction band
adjustment method described later.
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[0059]
(Large Diameter Speaker Unit 2, Insulating Shield Layer 95) The large diameter speaker unit 2
includes a vibrating unit 20. The vibrating portion 20 includes a dielectric layer 200, an inner
electrode layer 201, and an outer electrode layer 202. The inner electrode layer 201 and the
outer electrode layer 202 are each included in the concept of the “electrode layer” of the
present invention. The vibrating portion 20 is disposed on the outer peripheral surface of the
large diameter side holding portion 40.
[0060]
The configuration and the material of the large diameter speaker unit 2 are the same as the
configuration and the material of the small diameter speaker unit 3. The large diameter speaker
portion 2 is larger in diameter than the small diameter speaker portion 3. Further, the large
diameter speaker portion 2 is a longer axis than the small diameter speaker portion 3. In
addition, the insulating shield layer 95 covers the outer electrode layer 202 from the radially
outer side. The insulating shield layer 95 is made of H-NBR and has a cylindrical shape and a film
shape.
[0061]
As shown in FIG. 2, the area of the region P2 where the inner electrode layer 201 and the outer
electrode layer 202 overlap when viewed from the radially outer side or the radially inner side
corresponds to the electrode area S of the equation (2). Do. The area of the region P2 is larger
than the area of the region P1. The reproduction band of the large diameter speaker unit 2 is set
to a middle to low frequency band (medium bass region) by a reproduction band adjustment
method described later.
[0062]
(Circuit unit 8) As shown in FIG. 2, the circuit unit 8 includes a direct current bias power supply
80 and an alternating current power supply 81. The DC bias power supply 80 applies a DC bias
voltage to the small diameter speaker unit 3 and the large diameter speaker unit 2. The AC
power supply 81 applies an AC voltage based on the sound to be reproduced to the small
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diameter speaker unit 3 and the large diameter speaker unit 2. That is, the direct current bias
power supply 80 and the alternating current power supply 81 superimpose the direct current
bias voltage and the alternating current voltage, and apply them to the small diameter speaker
unit 3 and the large diameter speaker unit 2.
[0063]
The positive electrode side of the direct current bias power supply 80 is connected to the outer
electrode layer 302 of the small diameter speaker unit 3 and the outer electrode layer 202 of the
large diameter speaker unit 2 via an alternating current power supply 81. The negative electrode
side of the DC bias power supply 80 is connected to the inner electrode layer 301 of the small
diameter speaker portion 3 and the inner electrode layer 201 of the large diameter speaker
portion 2.
[0064]
[Speaker Movement] Next, the movement of the speaker of this embodiment will be described.
When an audio signal is input to the speaker 1, the AC voltage of the AC power supply 81
changes. For this reason, in the small diameter speaker portion 3, the electrostatic attractive
force between the inner electrode layer 301 and the outer electrode layer 302 changes. Thus, the
radial thickness of the dielectric layer 300 changes. That is, the dielectric layer 300 vibrates.
Therefore, the high-pitched portion of the sound is reproduced from the small diameter speaker
unit 3.
[0065]
Similarly, when an audio signal is input to the speaker 1, the AC voltage of the AC power supply
81 changes. For this reason, in the large diameter speaker portion 2, the electrostatic attraction
between the inner electrode layer 201 and the outer electrode layer 202 changes. Thus, the
radial thickness of the dielectric layer 200 changes. That is, the dielectric layer 200 vibrates.
Thus, the mid-bass portion of the sound is reproduced from the large diameter speaker unit 2.
[0066]
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18
[Reproduction Band Adjustment Method] Next, the reproduction band adjustment method of the
present embodiment will be described. The reproduction | regeneration band of the small
diameter speaker part 3 and the large diameter speaker part 2 is adjusted separately. FIG. 6
shows a schematic view of the frequency distribution of the sound pressure level of an arbitrary
speaker unit.
[0067]
As shown in FIG. 6, the lower limit value of the reproduction band L is the primary resonance
frequency f0. On the other hand, the upper limit value of the reproduction band L is the cutoff
frequency fc. Therefore, the reproduction band L can be expanded by widening the interval
between the primary resonance frequency f0 and the cutoff frequency fc. In addition, by
lowering the primary resonance frequency f0, the reproduction band L can be broadened to the
low frequency side. Further, by raising the cutoff frequency fc, the reproduction band L can be
expanded to the high frequency side. Further, the reproduction band L can be moved to the low
frequency side by lowering the primary resonance frequency f0 and the cutoff frequency fc.
Further, the reproduction band L can be moved to the high frequency side by raising the primary
resonance frequency f0 and the cutoff frequency fc.
[0068]
As described above, by adjusting at least one of the primary resonance frequency f0 and the
cutoff frequency fc, a desired reproduction band can be set in the small diameter speaker unit 3
and the large diameter speaker unit 2.
[0069]
Specifically, as shown in the above equation (1), at least one of the inner electrode layers 201
and 301, the electric resistance R of the outer electrode layers 202 and 302, and the capacitance
C of the dielectric layers 200 and 300. The cutoff frequency fc can be adjusted by adjusting.
That is, the upper limit value of the reproduction band L of the small diameter speaker unit 3 and
the large diameter speaker unit 2 can be adjusted.
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[0070]
The electrical resistance R of the inner electrode layers 201 and 301 and the outer electrode
layers 202 and 302 is the length of the conduction path of the inner electrode layers 201 and
301 and the outer electrode layers 202 and 302, the cross sectional area of the conduction path
(with respect to the path direction The cross-sectional area in the orthogonal direction), the inner
electrode layers 201 and 301, and the outer electrode layers 202 and 302 can be adjusted, for
example, by adjustment of materials.
[0071]
The electrical resistance R increases as the conduction path is lengthened.
Conversely, shortening the conduction path reduces the electrical resistance R. The electrical
resistance R decreases as the cross sectional area of the conduction path is increased. On the
contrary, when the cross sectional area of the conduction path is reduced, the electric resistance
R is increased.
[0072]
When a material having high conductivity is selected as a material for forming the inner
electrode layers 201 and 301 and the outer electrode layers 202 and 302, the electric resistance
R decreases. On the other hand, when a material having low conductivity is selected as the
material of the inner electrode layers 201 and 301 and the outer electrode layers 202 and 302,
the electric resistance R is increased. When the proportion of the material having high
conductivity in the materials constituting the inner electrode layers 201 and 301 and the outer
electrode layers 202 and 302 is increased, the electric resistance R decreases. On the other hand,
when the proportion of the material having high conductivity in the materials constituting the
inner electrode layers 201 and 301 and the outer electrode layers 202 and 302 is reduced, the
electric resistance R is increased.
[0073]
As shown in the above equation (2), the capacitance C of the dielectric layers 200 and 300 has
the dielectric constant ε of the dielectric layers 200 and 300, the electrode area S (specifically,
the regions P1 and P2 of FIG. 2). And the inter-electrode distance d (specifically, the thickness in
the radial direction of the dielectric layers 200 and 300).
09-05-2019
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[0074]
When a material having a high dielectric constant ε is selected as a material of the dielectric
layers 200 and 300, the capacitance C is increased.
On the contrary, when a material having a low dielectric constant ε is selected as a material of
the dielectric layers 200 and 300, the capacitance C is reduced. When the electrode area S is
increased, the capacitance C is increased. On the contrary, when the electrode area S is reduced,
the capacitance C is reduced. When the distance d between the electrodes is increased, the
capacitance C is reduced. On the contrary, when the distance d between the electrodes is
reduced, the capacitance C is increased.
[0075]
The surface direction of the vibrating parts 20 and 30 (direction in which the outer peripheral
surface of the dielectric layers 200 and 300 extends). That is, by adjusting the spring constant k
in the circumferential direction and the axial direction), it is possible to adjust the primary
resonance frequency f0, that is, the lower limit value of the reproduction band. Further, the
primary resonance frequency f0 can be adjusted by adjusting the mass m of the vibrating parts
20 and 30 (see the above-mentioned equation (3)). That is, the lower limit value of the
reproduction band L of the small diameter speaker unit 3 and the large diameter speaker unit 2
can be adjusted.
[0076]
If a material having a high Young's modulus is selected as a material for forming the dielectric
layers 200 and 300, the spring constant is increased. For this reason, the primary resonance
frequency f0 moves to the high frequency side. On the contrary, if a material having a low
Young's modulus is selected as a material for forming the dielectric layers 200 and 300, the
spring constant is reduced. For this reason, the primary resonance frequency f0 moves to the low
frequency side.
09-05-2019
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[0077]
When a material having a high Young's modulus is selected as a material for forming the inner
electrode layers 201 and 301 and the outer electrode layers 202 and 302, the spring constant is
increased. For this reason, the primary resonance frequency f0 moves to the high frequency side.
On the other hand, when a material having a low Young's modulus is selected as the material of
the inner electrode layers 201 and 301 and the outer electrode layers 202 and 302, the spring
constant is reduced. For this reason, the primary resonance frequency f0 moves to the low
frequency side.
[0078]
When the number of laminated layers of the dielectric layers 200 and 300 (the number of
laminated layers of the inner electrode layers 201 and 301 and the outer electrode layers 202
and 302) is increased, the spring constant k is increased. On the other hand, when the number of
stacked dielectric layers 200 and 300 (the number of stacked inner electrode layers 201 and
301 and outer electrode layers 202 and 302) is reduced, the spring constant k decreases. When
the number of stacked dielectric layers 200 and 300 (the number of stacked inner electrode
layers 201 and 301 and outer electrode layers 202 and 302) is increased, the mass m of the
vibrating portions 20 and 30 is increased. Conversely, when the number of stacked dielectric
layers 200 and 300 (the number of stacked inner electrode layers 201 and 301 and outer
electrode layers 202 and 302) is reduced, the mass m of the vibrating portions 20 and 30
decreases. As described above, k / m of the formula (3) can be adjusted by the number of
laminated layers of the dielectric layers 200 and 300 (the number of laminated layers of the
inner electrode layers 201 and 301 and the outer electrode layers 202 and 302).
[0079]
When the size of the vibrating parts 20 and 30 is increased, the mass m of the vibrating parts 20
and 30 is increased. For this reason, the primary resonance frequency f0 moves to the low
frequency side. On the contrary, when the size of the vibrating parts 20 and 30 is reduced, the
mass m of the vibrating parts 20 and 30 is reduced. For this reason, the primary resonance
frequency f0 moves to the high frequency side.
[0080]
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When a material having a high Young's modulus is selected as the material of the holding portion
4, the spring constants of the vibrating portions 20 and 30 increase. For this reason, the primary
resonance frequency f0 moves to the high frequency side. On the other hand, when a material
having a low Young's modulus is selected as the material of the holding portion 4, the spring
constant of the vibrating portions 20, 30 decreases. For this reason, the primary resonance
frequency f0 moves to the low frequency side.
[0081]
FIG. 7 shows a schematic view of the frequency distribution of the sound pressure level of the
speaker of the present embodiment. As shown in FIG. 7, by implementing the reproduction band
adjustment method, the reproduction band (medium and low frequency band) Lml of the large
diameter speaker unit 2 and the reproduction band of the small diameter speaker unit 3 from the
low frequency side to the high frequency side (High frequency band) Lh can be connected. For
this reason, the speaker 1 of the present embodiment can reproduce voice in a full range.
[0082]
[Operation and Effect] Next, the operation and effect of the speaker and the reproduction band
adjustment method of the present embodiment will be described. According to the speaker 1 of
this embodiment, the vibrating portions 20 and 30 include the dielectric layers 200 and 300
made of H-NBR (hydrogenated nitrile rubber), the inner electrode layers 201 and 301 made of a
flexible conductive material, and the outer electrode layer 202. , 302,. For this reason, the
speaker 1 of the present embodiment can be thinned compared to a conventional dynamic
speaker unit having a permanent magnet and a voice coil. Moreover, weight reduction is possible.
[0083]
In addition, the small diameter speaker unit 3 and the large diameter speaker unit 2 of the
speaker 1 according to the present embodiment can reproduce sounds in different reproduction
bands. For this reason, the speaker 1 can be miniaturized as compared with the case where
dedicated speakers are disposed for each reproduction band, such as a high frequency band and
09-05-2019
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a medium and low frequency band. Moreover, the weight of the speaker 1 can be reduced. In
addition, a single speaker 1 can reproduce a full range of audio.
[0084]
Moreover, the small diameter speaker part 3 and the large diameter speaker part 2 of the
speaker 1 of this embodiment each have the cylindrical vibration parts 20 and 30. For this
reason, sound can be reproduced toward all directions in the horizontal plane. That is, the
speaker 1 of this embodiment is omnidirectional.
[0085]
In addition, in the case of a speaker dedicated to the high frequency band, it is necessary to
separately provide a high pass filter in order to block the sound in the low frequency band. On
the other hand, in the case of a speaker dedicated to the low frequency band, it is necessary to
separately provide a low pass filter in order to block sound in the high frequency band. On the
other hand, according to the speaker 1 of this embodiment, it is not necessary to arrange a filter
separately. That is, there is no need to separately provide a dedicated circuit for frequency cutoff.
For this reason, the number of parts is reduced as compared to the case where dedicated
speakers are arranged for each reproduction band. Also, the circuit configuration is simple.
[0086]
Further, the speaker 1 of the present embodiment includes the holding unit 4. The holding unit 4
holds the vibrating units 20 and 30 from the inner side in the radial direction. Therefore,
although the dielectric layers 200 and 300, the inner electrode layers 201 and 301, and the
outer electrode layers 202 and 302 are soft and thin, the dielectric layers 200 and 300, the inner
electrode layers 201 and 301, and the outer electrode layers In 202, 302, it is hard to get
wrinkled.
[0087]
Moreover, the holding part 4 is made of urethane foam. For this reason, the holding unit 4 is
09-05-2019
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provided with a large number of holes. In addition, the holding unit 4 is flexible. Thus,
macroscopically, the dielectric layers 200 and 300, the inner electrode layers 201 and 301, and
the outer electrode layer 202 are formed so that the dielectric layers 200 and 300, the inner
electrode layers 201 and 301, and the outer electrode layers 202 and 302 do not wrinkle. , 302
can be held firmly. Also, microscopically, it is difficult to regulate fine vibrations of the dielectric
layers 200 and 300, the inner electrode layers 201 and 301, and the outer electrode layers 202
and 302. For this reason, the holding unit 4 does not easily inhibit the sound reproduction of the
small diameter speaker unit 3 and the large diameter speaker unit 2.
[0088]
Further, according to the speaker 1 of the present embodiment, the inner electrode layers 201
and 301 and the outer electrode layers 202 and 302 are formed by applying an electrode
material to the dielectric layers 200 and 300. Therefore, the formation of the inner electrode
layers 201 and 301 and the outer electrode layers 202 and 302 and the arrangement of the
inner electrode layers 201 and 301 and the outer electrode layers 202 and 302 can be
performed simultaneously.
[0089]
Further, according to the speaker 1 of the present embodiment, the holding portion 4 can be held
from the inside in the radial direction by the frame portion 7. Further, the frame 7 is provided
with a large number of communication holes 702 and 712. For this reason, air can be allowed to
pass through the anti-phase waves coming out of the inner circumferential surface of the
vibrating portion 20, 30 without becoming an air spring that inhibits the vibration to the outer
circumferential surface of the vibrating portion 20, 30. In addition, the frame 7 is an enclosure
for preventing sound diffraction.
[0090]
Moreover, according to the speaker 1 of this embodiment, the large diameter speaker is utilized
by utilizing the difference in the electrode area S (area P2> P1 in FIG. 2) due to the difference in
diameter between the large diameter speaker portion 2 and the small diameter speaker portion 3
Desired reproduction bands can be set in the portion 2 and the small diameter speaker portion 3
respectively.
09-05-2019
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[0091]
Further, according to the reproduction band adjustment method of the present embodiment, the
upper limit value and the lower limit value of the reproduction bands Lh and Lml can be easily
adjusted for each of the small diameter speaker portion 3 and the large diameter speaker portion
2.
That is, for each of the small diameter speaker portion 3 and the large diameter speaker portion
2, the size and position of the reproduction bands Lh and Lml can be easily adjusted.
[0092]
Second Embodiment The difference between the speaker and reproduction band adjustment
method of the present embodiment and the speaker and reproduction band adjustment method
of the first embodiment is that the speaker includes three speaker units. Here, only the
differences will be described.
[0093]
FIG. 8 shows an axial sectional view of the speaker of this embodiment. In addition, about the site
| part corresponding to FIG. 2, it shows with the same code | symbol. As shown in FIG. 8, the
speaker 1 according to this embodiment includes a first speaker unit 90, a second speaker unit
91, a third speaker unit 92, a holding unit 4, a frame 7, and a circuit unit 8. , And the insulating
shield layer 95. The first speaker unit 90, the second speaker unit 91, and the third speaker unit
92 are each included in the concept of the "speaker unit" in the present invention.
[0094]
The frame 7 includes a support 72, a base 73, a cylinder 74, a pair of upper and lower lids 75,
and a number of communication holes 76. The cylindrical portion 74 and the pair of upper and
lower lids 75 have a function as an enclosure. The pair of upper and lower lids 75 is made of
resin and has a disk shape. The pair of upper and lower lids 75 is annularly mounted on the
support column 72 at a predetermined interval in the vertical direction (axial direction). The
09-05-2019
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cylindrical portion 74 is disposed between the upper and lower lids 75. The cylindrical portion
74 is made of resin and has a cylindrical shape. The upper and lower openings of the cylindrical
portion 74 are sealed by the pair of upper and lower lids 75. A large number of communication
holes 76 are bored in the cylindrical portion 74. The communication hole 76 penetrates the
cylindrical portion 74 in the radial direction.
[0095]
The holding portion 4 is made of urethane foam and has a cylindrical shape. The holding portion
4 is disposed on the outer peripheral surface of the cylindrical portion 74. The inner electrode
layer 94 is disposed on the outer peripheral surface of the holding portion 4. The inner electrode
layer 94 is included in the concept of the “electrode layer” in the present invention. The inner
electrode layer 94 is made of a flexible conductive material in which silver powder is filled in
silicone rubber, and has a cylindrical shape and a film shape. The dielectric layer 93 is disposed
on the outer peripheral surface of the inner electrode layer 94. The dielectric layer 93 is made of
H-NBR (hydrogenated nitrile rubber), and has a cylindrical shape and a film shape.
[0096]
The first outer electrode layer 901 is disposed on the outer peripheral surface of the dielectric
layer 93. The first outer electrode layer 901 is included in the concept of the “electrode layer”
in the present invention. The first outer electrode layer 901 is made of a flexible conductive
material in which silver powder is filled in silicone rubber, and has a cylindrical shape and a film
shape.
[0097]
The second outer electrode layer 911 is disposed in the middle of the outer peripheral surface of
the dielectric layer 93. The second outer electrode layer 911 is included in the concept of the
“electrode layer” in the present invention. The second outer electrode layer 911 is made of a
flexible conductive material in which silver powder is filled in silicone rubber, and has a
cylindrical shape and a film shape.
[0098]
09-05-2019
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The third outer electrode layer 921 is disposed below the outer peripheral surface of the
dielectric layer 93. The third outer electrode layer 921 is included in the concept of the
“electrode layer” in the present invention. The third outer electrode layer 921 is made of a
flexible conductive material in which silver powder is filled in silicone rubber, and has a
cylindrical shape and a film shape.
[0099]
The insulating shield layer 95 covers the first outer electrode layer 901, the second outer
electrode layer 911, and the third outer electrode layer 921 from the radially outer side. The
insulating shield layer 95 is made of H-NBR and has a cylindrical shape and a film shape.
[0100]
In the vibrating portion 900 of the first speaker portion 90, the first outer electrode layer 901, a
portion of the dielectric layer 93, and a portion of the inner electrode layer 94 overlap when
viewed from the radially outer side or the radially inner side It is arranged in the area P5. The
area of the area P5 corresponds to the electrode area S of the equation (2).
[0101]
In the vibrating portion 910 of the second speaker portion 91, the second outer electrode layer
911, a portion of the dielectric layer 93, and a portion of the inner electrode layer 94 overlap
when viewed from the radially outer side or the radially inner side. It is arranged in the area P4.
The area of the region P4 corresponds to the electrode area S of the equation (2).
[0102]
The vibrating portion 920 of the third speaker portion 92 overlaps the third outer electrode layer
921, a portion of the dielectric layer 93, and a portion of the inner electrode layer 94 when
viewed from the radially outer side or the radially inner side. It is arranged in the area P3. The
09-05-2019
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area of the region P3 corresponds to the electrode area S of the equation (2).
[0103]
When the areas of the regions P3 to P5 are compared, it is P5> P4> P3. The first speaker unit 90
having the largest area reproduces audio in a low frequency band. The second speaker unit 91
having the second largest area reproduces the sound in the middle frequency band. The third
speaker unit 92 having the smallest area reproduces the sound in the high frequency band.
[0104]
The speaker and the reproduction band adjustment method of the present embodiment and the
speaker and the reproduction band adjustment method of the first embodiment have the same
function and effect as to the parts having the same configuration. Further, as in the speaker of
the present embodiment, three speaker units (first speaker unit 90, second speaker unit 91, and
third speaker unit 92) having different reproduction bands may be arranged. Further, the
cylindrical portion 74, the inner electrode layer 94, the dielectric layer 93, and the holding
portion 4 may be shared for the three speaker portions.
[0105]
<Others> The embodiments of the speaker and the reproduction band adjusting method of the
present invention have been described above. However, the embodiment is not particularly
limited to the above embodiment. It is also possible to carry out in various variants and
modifications which can be carried out by those skilled in the art.
[0106]
The configuration of the cylindrical portions 700, 710 and 74 of the frame portion 7 is not
particularly limited. For example, a wire mesh may be used. It is sufficient if a large number of
communication holes 702, 712, 76 can be secured. The lower lid portion 701 of the large
diameter side frame portion 70 of the first embodiment and the upper lid portion 711 of the
small diameter side frame portion 71 may be integrated.
09-05-2019
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[0107]
The vibrating portions 20, 30, 900, 910, and 920 may have an elliptical cylindrical shape, an
elongated cylindrical shape, a polygonal cylindrical shape (a triangular cylindrical shape, a
rectangular cylindrical shape, a pentagonal cylindrical shape, or the like) or the like. In addition,
the diameter may not be constant over the entire length of the vibrating portions 20, 30, 900,
910, and 920. That is, the vibrating portions 20, 30, 900, 910, and 920 may have a barrel shape,
a conical shape, a pyramid shape, a spherical shape, an elliptical shape, or the like. Moreover, as
for the vibration parts 20, 30, 900, 910, and 920, any cross section should just be annular.
[0108]
The vibrating parts 20, 30, 900, 910, 920 are flexible. Therefore, the degree of freedom in shape
is high. For example, by giving a desired shape to the frame portion 7 and the holding portion 4
and arranging the vibrating portions 20, 30, 900, 910, 920 on the outer surface thereof, the
vibrating portions 20, 30, 900, 910, 920 can be obtained. The shapes of the frame 7 and the
holder 4 can be transferred. That is, a desired shape can be given to the vibrating portions 20,
30, 900, 910, and 920.
[0109]
The method of arranging the inner electrode layers 201, 301, 94, the outer electrode layers 202,
302, the first outer electrode layer 901, the second outer electrode layer 911, and the third outer
electrode layer 921 with respect to the dielectric layers 200, 300, 93 is particularly limited. do
not do. For example, the inner electrode layers 201, 301, 94, the outer electrode layers 202, 302,
the first outer electrode layer 901, the second outer electrode layer 911, the third outer
electrode layer 921 manufactured separately from the dielectric layers 200, 300, 93. (For
example, the original sheet may be cut and produced) may be adhered to the dielectric layers
200, 300, 93. In this case, the inner electrode layers 201, 301, 94, the outer electrode layers
202, 302, the first outer electrode layer 901, the second outer electrode layer 911, the third
outer electrode layer 921 are firmly attached to the dielectric layers 200, 300, 93. It can be fixed
to
09-05-2019
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[0110]
The number of layers of the dielectric layers 200, 300, 93, the inner electrode layers 201, 301,
94, the outer electrode layers 202, 302, the first outer electrode layer 901, the second outer
electrode layer 911, the third outer electrode layer 921 is particularly limited. do not do. Further,
the arrangement number of the speaker units (the large diameter speaker unit 2, the small
diameter speaker unit 3, the first speaker unit 90, the second speaker unit 91, and the third
speaker unit 92) is not particularly limited.
[0111]
The material of the dielectric layers 200, 300, 93 is not particularly limited. It may be made of an
elastomer or a resin. For example, it is preferable to use an elastomer having a high dielectric
constant. Specifically, an elastomer having a relative dielectric constant (100 Hz) of 2 or more,
and more preferably 5 or more at normal temperature is preferable. For example, an elastomer
having a polar functional group such as an ester group, a carboxyl group, a hydroxyl group, a
halogen group, an amido group, a sulfone group, a urethane group or a nitrile group, or an
elastomer to which a polar low molecular weight compound having these polar functional groups
is added It is good to adopt As suitable elastomers other than H-NBR, silicone rubber,
acrylonitrile-butadiene rubber (NBR), ethylene-propylene-diene rubber (EPDM), acrylic rubber,
urethane rubber, epichlorohydrin rubber, chlorosulfonated polyethylene, chlorinated
polyethylene Etc. In addition, suitable resins include polyethylene, polypropylene, polyurethane,
polystyrene (including cross-linked expanded polystyrene), polyvinyl chloride, vinylidene
chloride copolymer, ethylene-vinyl acetate copolymer and the like. The material of the insulating
shield layer 95 is not particularly limited. The same material as the dielectric layers 200, 300,
and 93 may be used.
[0112]
The materials of the inner electrode layers 201, 301, 94, the outer electrode layers 202, 302, the
first outer electrode layer 901, the second outer electrode layer 911, and the third outer
electrode layer 921 are not particularly limited. For example, silicone rubber, acrylic rubber,
silver powder in H-NBR, and a flexible conductive material filled with carbon may be used. The
inner electrode layers 201, 301, 94, the outer electrode layers 202, 302, the first outer electrode
layer 901, the second outer electrode layer 911, and the third outer electrode layer 921 may be
formed of a metal or a carbon material. From the viewpoint of imparting stretchability, the inner
09-05-2019
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electrode layers 201, 301, 94, the outer electrode layers 202, 302, the first outer electrode layer
901, the second outer electrode layer 911, for example, are knitted by meshing metal or the like.
, And the third outer electrode layer 921 can be formed. In addition, from the conductive
polymer such as polyethylenedioxythiophene (PEDOT), the inner electrode layers 201, 301, 94,
the outer electrode layers 202, 302, the first outer electrode layer 901, the second outer
electrode layer 911, the third outer side The electrode layer 921 may be formed. When a flexible
conductive material containing a binder and a conductive material is employed, it is preferable to
use an elastomer as the binder. As the elastomer, for example, silicone rubber, NBR, EPDM,
natural rubber, styrene-butadiene rubber (SBR), acrylic rubber, urethane rubber, epichlorohydrin
rubber, chlorosulfonated polyethylene, chlorinated polyethylene and the like are preferable. In
addition, as the conductive material, carbon materials such as carbon black, carbon nanotubes
and graphite, silver, gold, copper, nickel, rhodium, palladium, chromium, titanium, platinum, iron
and metal materials such as alloys thereof, indium oxide It may be appropriately selected from
conductive oxides such as tin (ITO), titanium oxide, and zinc oxide doped with other metals such
as aluminum and antimony. A conductive material may be used individually by 1 type, and may
mix and use 2 or more types. The material of the holding portion 4 is not particularly limited. For
example, the holding portion 4 may be formed of a foamed urethane sponge.
[0113]
1: Speaker, 2: Large diameter speaker part, 3: Small diameter speaker part, 4: Holding part, 7:
Frame part, 8: Circuit part. 20: Vibrating part, 30: Vibrating part, 40: Large diameter side holding
part, 41: Small diameter side holding part, 70: Large diameter side frame part, 71: Small diameter
side frame part, 72: Support part, 73: Base, 74 : Tube part 75: Lid part 76: Communication hole
80: DC bias power supply 81: AC power supply 90: first speaker part (speaker part) 91: second
speaker part (speaker part) 92: second Three speakers (speaker), 93: dielectric layer, 94: inner
electrode layer (electrode layer), 95: insulating shield layer. 200: dielectric layer, 201: inner
electrode layer (electrode layer), 202: outer electrode layer (electrode layer), 300: dielectric layer,
301: inner electrode layer (electrode layer), 302: outer electrode layer (electrode layer), 700:
cylindrical portion 701: lid portion 702: communication hole 710: cylindrical portion 711: lid
portion 712: communication hole 900: vibration portion 901: first outer electrode layer
(electrode layer) 910: vibration Part, 911: Second outer electrode layer (electrode layer), 920:
Vibrating part, 921: Third outer electrode layer (electrode layer). L: reproduction band, Lh:
reproduction band, Lml: reproduction band, P1 to P5: area, f0: primary resonance frequency, fc:
cutoff frequency.
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