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JP2012209919

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DESCRIPTION JP2012209919
The present invention relates to a thermoacoustic apparatus, and more particularly to a
thermoacoustic apparatus using carbon nanotubes. A thermoacoustic apparatus according to the
present invention includes an acoustic wave generator and a heater. The sound wave generator is
installed on one surface of the sound wave generator. The sound wave generator comprises a
graphene-carbon nanotube composite structure. The graphene-carbon nanotube composite
structure may include at least one graphene structure and at least one carbon nanotube structure
stacked and installed on each other. The carbon nanotube structure is a freestanding structure
having a plurality of micropores. The thermoacoustic apparatus, wherein the heat generator
provides energy to the sound wave generator and generates heat from the sound wave generator.
[Selected figure] Figure 1
Thermoacoustic device
[0001]
The present invention relates to a thermoacoustic device, and more particularly to a
thermoacoustic device using graphene.
[0002]
In general, an acoustic device comprises a signal device and a sound generator.
The signaling device transmits a signal to the sound generator. The thermoacoustic device is a
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type of acoustic device that utilizes a thermoacoustic phenomenon. Non-Patent Document 1 and
Non-Patent Document 2 disclose thermoacoustic devices in which sound is generated by heat
when an alternating current flows through a conductor. When alternating current is applied to
the conductor, heat is generated in the thermoacoustic apparatus and is propagated to the
surrounding medium. Sound waves can be generated due to thermal expansion and pressure
waves generated by the transmitted heat.
[0003]
Patent Document 1: JP-A-2004-107196 Patent Document 2: US Patent No. 2008248235 Patent
Document 2: JP-A-2006-161563 Patent Document 2: Chinese Patent Application Publication No.
101284662 Patent Document 2: JP-A 2008-297195
[0004]
The Thermophone,EDWARD C. WEMTE,Vol.
XTX,No.4,p.333−345 On Some Thermal Effects of
Electric Currents,William Henry
Preece,Proceedings of the Roal Society of
London,Vol.30,p.408−411(1879−1881)
H.D.Arnold、I.B.Crandall, “The thermophone as a
precision source of sound”, Phys. 1917, 10, 22-38, Kaili Jiang,
Qunqing Li, Shoushan Fan, "Spinning continuous carbon nanotube yarns", Nature, 2002, 419, p.
801
[0005]
Non-Patent Document 3 discloses a thermophone manufactured by a thermoacoustic
phenomenon. Thermoacoustic phenomenon is a phenomenon in which sound and heat are
related, and there are two aspects, energy conversion and energy transport. Transferring the
signal to the thermoacoustic device generates heat in the thermoacoustic device and propagates
to the surrounding media. Sound waves can be generated by thermal expansion and pressure
waves generated by the transmitted heat. Here, a platinum piece having a thickness of 7 × 10 <5> cm is used as a thermoacoustic component. However, for a platinum piece having a thickness
of 7 × 10 <-5> cm, the heat capacity per unit area is 2 × 10 <-4> J / cm <2> · K. Since the heat
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capacity per unit area of platinum pieces is very large, there is a problem that the thermoacoustic
frequency and the thermoacoustic effect are low when the thermophone using platinum pieces is
used outdoors.
[0006]
Accordingly, the present invention provides thermoacoustic devices and electronic devices for
solving the above-mentioned problems. That is, the thermoacoustic frequency and the
thermoacoustic effect of the thermoacoustic device and the electronic device are high.
[0007]
The thermoacoustic apparatus of the present invention includes a sound wave generator and a
heater. The heater is installed on one surface of the sound wave generator. The sound wave
generator comprises a graphene-carbon nanotube composite structure. The graphene-carbon
nanotube composite structure may include at least one graphene structure and at least one
carbon nanotube structure stacked and installed on each other. The carbon nanotube structure is
a freestanding structure having a plurality of micropores. The graphene structure is disposed on
one surface of the carbon nanotube structure to cover the plurality of pores. The heater provides
energy to the sound generator and generates heat from the sound generator.
[0008]
The thermoacoustic apparatus further includes a substrate. The substrate has at least one
through hole. The sound wave generator is disposed on the surface of the substrate. At least a
portion of the sound wave generator is suspended relative to the at least one through hole.
[0009]
In an electronic device including the thermoacoustic device of the present invention, the
thermoacoustic device includes a sound wave generator and a heater. The heater is installed on
one surface of the sound wave generator. The sound wave generator comprises a graphenecarbon nanotube composite structure. The graphene-carbon nanotube composite structure may
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include at least one graphene structure and at least one carbon nanotube structure stacked and
installed on each other. The carbon nanotube structure is a freestanding structure having a
plurality of micropores. The graphene structure is disposed on one surface of the carbon
nanotube structure to cover the plurality of pores. The heater provides energy to the sound
generator and generates heat from the sound generator.
[0010]
Compared to the prior art, the thermoacoustic apparatus of the present invention has the
following advantages. First, since the thermoacoustic device of the present invention includes a
graphene-carbon nanotube composite structure, the configuration is simple, and weight
reduction and miniaturization are possible. Second, since the thermoacoustic device of the
present invention generates an acoustic wave by heating the graphene-carbon nanotube
composite structure, it is not necessary to use a magnet. Third, since the graphene structure has
a small heat capacity per unit area, a large specific surface area, and a high rate of heat
exchange, sound can be favorably generated.
[0011]
It is a top view of the thermoacoustic apparatus which concerns on Example 1 of this invention.
It is sectional drawing of the thermoacoustic apparatus which concerns on Example 1 along line |
wire II-II of FIG. It is a figure which shows the graphene carbon nanotube composite structure in
the thermoacoustic apparatus which concerns on Example 1 of this invention. FIG. 7 is a view
showing graphene in the graphene structure in the graphene-carbon nanotube composite
structure according to the first embodiment of the present invention. It is a scanning electron
micrograph of the carbon nanotube structure in the graphene carbon nanotube composite
structure which concerns on Example 1 of this invention. It is a figure which shows the structure
of the carbon nanotube segment of the carbon nanotube film in FIG. It is a scanning electron
micrograph of the carbon nanotube structure which consists of a plurality of cross | intersecting
carbon nanotube strip structures in the graphene carbon nanotube composite structure which
concerns on Example 1 of this invention. It is a figure which shows the graphene carbon
nanotube composite structure in the thermoacoustic apparatus which concerns on Example 1 of
this invention. In a graphene carbon nanotube compound structure concerning Example 1 of the
present invention, it is a figure showing a carbon nanotube structure which consists of a treated
carbon nanotube film. It is a scanning electron micrograph of the carbon nanotube structure
which consists of the carbon nanotube film processed by the laser in the graphene carbon
nanotube composite structure which concerns on Example 1 of this invention. It is a scanning
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electron micrograph of the carbon nanotube structure which consists of a carbon nanotube film
processed with alcohol in the graphene carbon nanotube composite structure concerning
Example 1 of the present invention. FIG. 6 is a view showing a carbon nanotube structure
composed of a plurality of linear carbon nanotube structures in the graphene-carbon nanotube
composite structure according to the first embodiment of the present invention. It is a scanning
electron micrograph of the non-twisted carbon nanotube wire utilized for the carbon nanotube
structure in the graphene carbon nanotube composite structure which concerns on Example 1 of
this invention. It is a scanning electron micrograph of the twist-like carbon nanotube wire utilized
for the carbon nanotube structure in the graphene carbon nanotube composite structure which
concerns on Example 1 of this invention. It is a figure which shows the manufacturing method of
the carbon nanotube film utilized for the graphene carbon nanotube composite structure which
concerns on Example 1 of this invention.
It is a top view of the thermoacoustic apparatus which concerns on Example 2 of this invention.
It is sectional drawing of the thermoacoustic apparatus which concerns on Example 2 along line
XVII-XVII of FIG. It is a top view of the thermoacoustic apparatus which concerns on Example 3
of this invention. It is sectional drawing of one thermoacoustic apparatus which concerns on
Example 3 along line XIX-XIX of FIG. FIG. 18 is a cross-sectional view of another thermoacoustic
device according to Example 3, taken along line XIX-XIX in FIG. 17. It is a top view of the
thermoacoustic apparatus which concerns on Example 4 of this invention. FIG. 21 is a crosssectional view of the thermoacoustic device in accordance with the fourth embodiment, taken
along line XXII-XXII in FIG. 20. It is a sectional side view of a thermoacoustic device containing a
substrate which consists of a carbon nanotube structure where the surface was covered with an
insulating layer concerning Example 5 of the present invention. It is a scanning electron
micrograph of the fluff structure carbon nanotube film utilized for the carbon nanotube structure
of FIG. FIG. 24 is a scanning electron micrograph of a presided carbon nanotube film in which the
carbon nanotubes used for the carbon nanotube structure of FIG. 23 are arranged without
orientation. It is a scanning electron micrograph of the presid structure carbon nanotube film by
which the carbon nanotube utilized for the carbon nanotube structure of FIG. 23 is orientated
and arrange | positioned. It is a top view of the thermoacoustic apparatus which concerns on
Example 6 of this invention. It is sectional drawing of the thermoacoustic apparatus which
concerns on Example 6 which followed line | wire XXVIII-XXVIII of FIG. It is a top view of the
thermoacoustic apparatus which concerns on Example 7 of this invention. FIG. 28 is a crosssectional view of the thermoacoustic device in accordance with the seventh embodiment, taken
along the line XXXI-XXXI of FIG. It is a sectional side view of the thermoacoustic apparatus
which concerns on Example 8 of this invention. It is a sectional side view of the thermoacoustic
apparatus which concerns on Example 9 of this invention. It is a side view of the thermoacoustic
apparatus which concerns on Example 10 of this invention.
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[0012]
Hereinafter, embodiments of the present invention will be described with reference to the
drawings.
[0013]
Example 1 Referring to FIGS. 1 and 2, the thermoacoustic apparatus 10 of the present example
includes a sound wave generator 102 and a heater 104.
[0014]
The heat generator 104 can provide energy to the sound wave generator 102, and heat can be
generated from the sound wave generator 102, whereby the thermoacoustic device 10 can
generate a sound wave.
In the present embodiment, the heater 104 includes a first electrode 104a and a second
electrode 104b disposed at a predetermined distance from the first electrode 104a.
The first electrode 104 a and the second electrode 104 b are electrically connected to the sound
wave generator 102. In the present embodiment, the first electrode 104a and the second
electrode 104b are disposed on the same surface of the sound wave generator 102 and are
parallel to two opposing sides of the sound wave generator 102.
[0015]
The thermoacoustic device 10 can generate a sound wave by providing the electric wave
generator 102 with an electric signal and generating heat from the sound wave generator 102. .
The first electrode 104a and the second electrode 104b may be formed in a layered, rod-like,
strip-like or lump-like shape, and their cross sections may be circular, square, trapezoidal,
triangular or polygonal. The first electrode 104 a and the second electrode 104 b are fixed to one
surface of the sound wave generator 102 by an adhesive. In order to prevent heat generated
from the sound wave generator 102 from being absorbed by the first electrode 104 a and the
second electrode 104 b, the heat of the sound wave generator 102 and the first electrode 104 a
It is preferable to provide a small contact area. The first electrode 104a and the second electrode
104b are thread-like or strip-like, and the material is any one of metal, conductive adhesive,
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conductive paste, ITO, and conductive material such as carbon nanotube. In the present
embodiment, the first electrode 104 a and the second electrode 104 b are thread-like silver
electrodes formed on one surface of the sound wave generator 102 by printing conductive silver
paste.
[0016]
If the first electrode 104a and the second electrode 104b have a certain strength, the first
electrode 104a and the second electrode 104b may support the sound wave generator 102. For
example, when both ends of the first electrode 104a and the second electrode 104b are fixed to
one frame, the sound wave generator 102 is installed and suspended on the first electrode 104a
and the second electrode 104b. .
[0017]
The thermoacoustic device 10 further includes a lead (not shown) of the first electrode and a lead
(not shown) of the second electrode. The lead wire of the first electrode and the lead wire of the
second electrode are electrically connected to the first electrode 104a and the second electrode
104b, respectively. The thermoacoustic device 10 is electrically connected to an external circuit
(not shown) by the lead wire of the first electrode and the lead wire of the second electrode.
[0018]
The sound wave generator 102 is composed of a graphene-carbon nanotube composite structure
2. Referring to FIG. 3, the graphene-carbon nanotube composite structure 2 includes a carbon
nanotube structure 22 and a graphene structure 38 disposed on one surface of the carbon
nanotube structure 22. The carbon nanotube structure 22 comprises at least one carbon
nanotube film 28. The carbon nanotube film 28 is composed of a plurality of aligned and aligned
carbon nanotubes. A plurality of carbon nanotubes are connected to the carbon nanotube film 28
by an intermolecular force. A plurality of fine holes 24 are formed in the carbon nanotube
structure 22.
[0019]
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The graphene structure 38 is a two-dimensional integral structure having a predetermined area.
Here, the graphene structure 38 being an integral structure means having continuity on a plane.
The graphene structure 38 is disposed on and integrated with one surface of the carbon
nanotube structure 22 and covers a plurality of micropores 24 in the carbon nanotube structure
22. If the area of the graphene structure 38 is smaller than the area of the carbon nanotube
structure 22, the graphene structure 38 may cover some of the micropores 24 in the carbon
nanotube structure 22. The graphene structure 38 is made of one to five layers of graphene,
preferably one layer of graphene. The thickness of the graphene structure 38 may be 0.34 nm to
10 nm. When the graphene structure 38 includes a plurality of graphene sheets, the plurality of
graphene sheets are connected in parallel to form a graphene structure 38 having a large area or
a stacked graphene structure. Form the body 38. Referring to FIG. 4, the graphene in the
graphene structure 38 is a sheet of one atomic thickness of sp <2> -bonded carbon atoms, and
has a hexagonal lattice structure like a honeycomb formed of carbon atoms and their bonds. It is
taking.
[0020]
Since the transmissivity of single-layer graphene reaches 97.7%, the graphene structure 38
formed of the single-layer graphene has good translucency. The graphene structure 38 is very
thin, so its heat capacity is small. For example, the heat capacity of single-layer graphene is 5.57
× 10 <-4> J / K · mol. The graphene structure 38 has a free standing structure. Here, a selfsupporting structure is a form which can utilize the said graphene structure 38 independently,
without using a support material. That is, it means that the graphene structure 38 can be
suspended without changing the structure of the graphene structure 38 by supporting the
graphene structure 38 from opposite sides. The dimensions of the graphene structure 38 are 1
cm or more. Here, the dimension of the graphene structure 38 is a distance when the distance
from one point to another point of the graphene structure 38 is maximum. The area of the
orthographic projection of the graphene structure 38 is 1 cm <2> or more. The dimensions of the
graphene structure 38 are selected according to the actual application. In the present
embodiment, the graphene structure 38 is formed of a single layer of graphene, and its shape is a
square having a side length of 4 cm.
[0021]
The carbon nanotube structure 22 is a planar structure including at least one carbon nanotube
film 28. Referring to FIG. 5, in the carbon nanotube film 28, ends of the plurality of carbon
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nanotubes are connected by an intermolecular force along the same direction. The carbon
nanotube film 28 has excellent electrical conductivity along the arrangement direction of the
plurality of carbon nanotubes. Referring to FIG. 5, since the carbon nanotube film 28 has a
plurality of strip-shaped gaps along the arrangement direction of the plurality of carbon
nanotubes, the carbon nanotube film 28 has good transparency. Here, the plurality of stripshaped gaps is a gap between two adjacent carbon nanotubes. The width of the single gap is 1
μm to 10 μm. Referring to FIG. 7, in the present embodiment, the carbon nanotube structure
22 is composed of two stacked carbon nanotube films 28. The carbon nanotubes in the adjacent
carbon nanotube film 28 intersect with each other at 90 ° to form a plurality of micro holes 24.
Thereby, the carbon nanotube structure 22 has a good light transmitting property. The
dimensions of the single micropore 24 are 1 μm to 10 μm.
[0022]
The carbon nanotube structure has a freestanding structure, and its thickness is 10 μm to 2 mm.
The plurality of carbon nanotubes in the carbon nanotube structure 22 may be one or more of
single-walled carbon nanotubes, double-walled carbon nanotubes, or multi-walled carbon
nanotubes. When the carbon nanotube is a single-walled carbon nanotube, the diameter is set to
0.5 nm to 50 nm, and when the carbon nanotube is a double-walled carbon nanotube, the
diameter is set to 1 nm to 50 nm, and the carbon nanotube is a multilayer carbon In the case of
nanotubes, the diameter is set to 1.5 nm to 50 nm. The heat capacity per unit area of the carbon
nanotube structure 22 is 0 (not including 0) to 2 × 10 <-4> J / cm <2> · K, but preferably 0 (not
including 0). ) To 1.7 × 10 <-6> J / cm <2> · K, and in the present embodiment, it is 1.7 × 10 <6> J / cm <2> · K.
[0023]
Referring to FIG. 8, the graphene-carbon nanotube composite structure 2 of the present example
includes the carbon nanotube structure 22 and the graphene structure 38 in which one surface
of the carbon nanotube structure 22 is coated. The carbon nanotube structure 22 is formed of a
single carbon nanotube film 28. The graphene structure 38 has good transparency, and the
carbon nanotube structure 22 has a plurality of micropores, so the graphene-carbon nanotube
composite structure 2 also has good transparency. Have. Furthermore, since the carbon nanotube
structure 22 and the graphene structure 38 have a low heat capacity per unit area, the graphenecarbon nanotube composite structure 2 also has a low heat capacity per unit area.
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[0024]
Referring to FIG. 9, the carbon nanotube structure 22 of the present embodiment can also be
made of a treated carbon nanotube film 28. By treating the carbon nanotube film 28 with an
organic solvent or a laser, it is possible to enlarge the strip-like gaps of the carbon nanotube film
28 and to enlarge the dimensions of the plurality of micropores 24 in the carbon nanotube
structure 22. . The dimensions of the plurality of pores 24 can be selected according to the
practical application, and are, for example, 10 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500
μm, 600 μm, 700 μm, 800 μm, 900 μm, 1000 μm. Preferably, the dimensions of the
plurality of pores 24 are 200 μm to 600 μm.
[0025]
The carbon nanotube film 28 may be treated with a laser. Referring to FIG. 10, laser treatment
causes a portion of the carbon nanotube film 28 to be ablated or a portion of a plurality of
carbon nanotubes to be shrunk. Thus, the carbon nanotube film 28 is formed into a plurality of
carbon nanotube strip structures 26.
[0026]
Referring to FIG. 11, by treating the carbon nanotube film 28 with an organic solvent, the striplike gap of the carbon nanotube film 28 can be increased.
[0027]
In the carbon nanotube film 28 treated with the organic solvent or laser, when the size of the
plurality of micropores 24 is large, the graphene structure 38 coated on one surface of the
carbon nanotube structure 22 is in contact with air. Increase the area to be
Thereby, compared with the said untreated carbon nanotube film 28, the heat capacity per unit
area of the said carbon nanotube film 28 processed with the said organic solvent or laser is low.
[0028]
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In the organic solvent or laser-treated carbon nanotube film 28, the ratio of the area of the
plurality of carbon nanotubes arranged in parallel to the area of the plurality of micropores is
small. The width of the carbon nanotube band structure 26 is 200 nm to 10 μm. The ends of the
plurality of carbon nanotubes in the carbon nanotube band structure 26 are connected by an
intermolecular force along the same direction, and the width of the plurality of band gaps is 10
μm to 220 μm, but 22 μm to 500 μm Is preferred. The carbon nanotube structure 22 of FIG.
10 is formed by laminating two sheets of carbon nanotube films 28 having a plurality of carbon
nanotube band-shaped structures 26 processed by laser. An angle α between carbon nanotubes
in the adjacent carbon nanotube film 28 is 0 ° to 90 °. In the present embodiment, the angle α
is 90 °.
[0029]
In the carbon nanotube film 28 treated with the organic solvent or laser, since the ratio of the
area of the plurality of carbon nanotubes to the area of the plurality of micropores is small, the
carbon nanotube structure 22 composed of the carbon nanotube film 28 is also The ratio of the
area of the plurality of carbon nanotubes to the area of the plurality of micropores is reduced.
The ratio of the area of the plurality of carbon nanotubes to the area of the plurality of
micropores in the carbon nanotube structure 22 is 1: 1000 to 1:10, but preferably 1: 100 to
1:10. Thus, the graphene-carbon nanotube composite structure 10 including the carbon
nanotube structure 22 directly covers the micropores 24 of the carbon nanotube structure 22
with most of the graphene structure 38. It can touch. The thermoacoustic device using the
graphene-carbon nanotube composite structure 2 can enhance the thermoacoustic effect.
[0030]
The method of manufacturing the graphene-carbon nanotube composite structure 2 includes a
first step of providing the carbon nanotube structure 22 and providing the graphene structure
38 as the carbon nanotube structure 22. And a second step of coating on one surface.
[0031]
In the first step, the carbon nanotube structure 22 comprises one or a plurality of laminated
carbon nanotube films 28.
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Referring to FIG. 15, in the present embodiment, the carbon nanotube film 28 is a drawn carbon
nanotube film. The method of manufacturing the carbon nanotube film 28 includes a step a11 of
providing a super aligned carbon nanotube array 286 (refer to Non-Patent Document 4), and at
least one carbon nanotube from the carbon nanotube array 286. Stretching the film to obtain the
carbon nanotube film 28.
[0032]
In the step a11, the method of manufacturing the super-aligned carbon nanotube array 286
employs chemical vapor deposition. The carbon nanotube array 286 is composed of a plurality of
carbon nanotubes parallel to each other and grown perpendicularly to the substrate. The carbon
nanotubes are intertwined in close proximity by intermolecular force. The carbon nanotubes are
single-walled carbon nanotubes, double-walled carbon nanotubes or multi-walled carbon
nanotubes, and the diameter thereof is set to 0.5 nm to 50 nm. In the present embodiment, the
length of the carbon nanotube is 100 to 900 μm.
[0033]
In the step a12, the carbon nanotube film 28 comprises a plurality of carbon nanotubes, and
there is a gap between the adjacent carbon nanotubes. In the carbon nanotube film 28, the
plurality of carbon nanotubes are arranged in parallel to the surface of the carbon nanotube film
28 and arranged in parallel to each other. In the step of stretching the carbon nanotube film 28,
a substep a121 of selecting a carbon nanotube segment having a certain width in the superaligned carbon nanotube array 286, and the carbon nanotube segments are drawn at a
predetermined speed, and a plurality of carbon nanotube segments are extracted. And substep
a122 of forming a continuous carbon nanotube film 28 consisting of 282.
[0034]
In the sub-step a121, a carbon nanotube segment 282 having the predetermined width is
selected from the super-aligned carbon nanotube array 286 using a tool such as an adhesive
tape, a pliers, and a pincer. The carbon nanotube segment 282 includes a plurality of carbon
nanotubes arranged in parallel to one another. In the substep a122, the carbon nanotube
segment can be drawn out along any direction.
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[0035]
Specifically, in the step of drawing out the plurality of carbon nanotube segments 282, when the
plurality of carbon nanotube segments 282 are respectively detached from the base material, the
carbon nanotube segments 282 are joined end to end by the intermolecular force, and they are
continuous. Carbon nanotube film 28 is formed. The carbon nanotube film 28 has a free standing
structure. The carbon nanotube film 28 has a uniform width and is uniformly arranged. A
method for producing the drone structured carbon nanotube film is disclosed in Patent
Document 2.
[0036]
In the carbon nanotube film 28, the carbon nanotubes are connected end to end along the same
direction. That is, the single carbon nanotube film 28 is composed of a plurality of carbon
nanotubes whose longitudinal ends are connected to each other by intermolecular force. 5 and 6,
a single carbon nanotube film 143a includes a plurality of carbon nanotube segments 143b. The
plurality of carbon nanotube segments 143b are connected end-to-end with intermolecular force
along the longitudinal direction. Each carbon nanotube segment 143b includes a plurality of
carbon nanotubes 145 connected by intermolecular force in parallel to each other. The lengths of
the plurality of carbon nanotubes 145 in the single carbon nanotube segment 143b are the same.
The width, thickness, uniformity and shape of the carbon nanotube film 143a may be varied.
[0037]
Furthermore, the carbon nanotube film 28 obtained in the step a12 may be treated with an
organic solvent or a laser. In the method of treating the carbon nanotube film 28 with a laser, a
step S1 of stretching the carbon nanotube film 28 from the carbon nanotube array 286 (see FIG.
15), and fixing the carbon nanotube film 28 on one support Step S2; and Step S3 of cauterizing
the carbon nanotube film 28 along the arrangement direction of the plurality of carbon
nanotubes in the carbon nanotube film 28 by a laser to form a plurality of carbon nanotube strip
structures 26; Including.
[0038]
After caulking a part of the carbon nanotube film 28 by controlling the laser power, the
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wavelength, and the moving speed thereof in the step S3, a plurality of carbon nanotube strip
structures 26 are formed on the carbon nanotube film 28. It can be formed.
[0039]
In the method of treating the carbon nanotube film 28 with an organic solvent, the organic
solvent is dropped on the surface of the carbon nanotube film 28 with a dropper, and the carbon
nanotube film 28 is dipped in the organic solvent.
Alternatively, the entire carbon nanotube film 28 may be immersed in an organic solvent. By
treating with the organic solvent, the surface tension of the organic solvent eliminates the gap
between the adjacent carbon nanotubes, and the carbon nanotube band structure 26 is formed of
the carbon nanotubes. Thereby, the dimensions of the plurality of micro holes 24 in the carbon
nanotube film 28 become large. The organic solvent is, for example, any one kind of volatile
organic solvent such as ethanol, methanol, acetone, dichloroethane, chloroform and the like. In
the present embodiment, the organic solvent is ethanol. The organic solvent has good wettability
to the carbon nanotube film 28.
[0040]
When the carbon nanotube structure 22 comprises at least two stacked carbon nanotube films
28, the method of manufacturing the carbon nanotube film 22 includes at least two carbon
nanotube films (defined as first carbon nanotube films). Securing a side to one frame (not shown)
and suspending another portion of the first carbon nanotube film, and another carbon nanotube
film (defined as a second carbon nanotube film) And b) coating the first carbon nanotube film on
the first carbon nanotube film. The carbon nanotubes in the first carbon nanotube film are
aligned along a first direction, while the carbon nanotubes in the second carbon nanotube film
are aligned along a second direction. The first direction and the second direction intersect at 0 °
to 90 ° (not including 0 °). The carbon nanotube structure 22 composed of the plurality of
carbon nanotube films 28 stacked is fixed to the frame by the above-described manufacturing
method. The carbon nanotubes in each of the carbon nanotube films 28 may be arranged along
different directions.
[0041]
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Referring to FIG. 7, since the carbon nanotube film 28 has a large specific surface area and high
adhesion, the stacked carbon nanotube films 28 are closely coupled to each other by
intermolecular force and stabilized. The carbon nanotube structure 22 can be formed. The
number of carbon nanotube films 28 in the carbon nanotube structure 22 is not limited. In the
present embodiment, the number of carbon nanotube films is two to four. The carbon nanotubes
in the adjacent carbon nanotube film intersect at 90 °.
[0042]
When the carbon nanotube structure 22 comprises at least two stacked carbon nanotube films
28 processed by the laser, the carbon nanotube structure 22 is further treated with an organic
solvent to obtain the carbon nanotube structure. The plurality of micropores 24 of the body 22
can be enlarged to tightly bond the adjacent carbon nanotube films 28. The organic solvent is,
for example, any one kind of volatile organic solvent such as ethanol, methanol, acetone,
dichloroethane, chloroform and the like. In the present embodiment, the organic solvent is
ethanol. The organic solvent has good wettability to the carbon nanotube structure 22.
Specifically, an organic solvent is dropped onto the surface of the carbon nanotube structure 22
with a dropper, and the carbon nanotube structure 22 is immersed in the organic solvent.
Alternatively, all of the carbon nanotube structures 22 may be immersed in an organic solvent.
Referring to FIG. 11, when the carbon nanotube structure 22 comprises at least two stacked
drone-structured carbon nanotube films, the plurality of adjacent carbon nanotubes are treated
by the surface tension of the organic solvent by treating with the organic solvent. The gaps
between the carbon nanotubes are eliminated, and the plurality of carbon nanotubes form a
carbon nanotube band structure 26. As a result, the dimensions of the plurality of micropores 24
in the carbon nanotube structure 22 become large. The dimensions of the micropores 24 in the
carbon nanotube structure 22 are 10 μm to 1000 μm, and preferably 200 μm to 600 μm. In
the present embodiment, the plurality of carbon nanotube strip structures 26 intersect with each
other at 90 ° (not including 0 °). By treating the carbon nanotube structure 22 with an organic
solvent, its adhesiveness can be lowered. As the number of the carbon nanotube films 28 in the
carbon nanotube structure 22 increases, the size of the micropores 24 in the carbon nanotube
structure 22 decreases. Therefore, by adjusting the number of carbon nanotube films in the
carbon nanotube structure 22, it is possible to obtain micropores 24 of a desired size.
[0043]
In the second step, the method of manufacturing the graphene structure 38 may be a chemical
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vapor deposition method, a coating method or a mechanical exfoliation method. In the present
embodiment, the graphene structure 38 is formed on the surface of a substrate made of a metal
film by chemical vapor deposition. Specifically, in the method for producing the graphene
structure 38, a step a151 of providing a substrate made of a metal film, and the substrate is
placed in a reaction chamber, and carbon gas is introduced into the reaction chamber at high
temperature to Growing graphene on one surface of the substrate, and cooling the metal film
having graphene to room temperature to form the graphene structure 38 on one surface of the
substrate.
[0044]
In the step a151, the substrate is made of copper foil or nickel foil, and its size and shape
correspond to the size and shape of the reaction chamber. The thickness of the substrate is 12.5
μm to 50 μm. In the present embodiment, the substrate is made of copper foil and has a
thickness of 12.5 μm to 50 μm, preferably 25 μm.
[0045]
In the step a152, the reaction chamber is a quartz tube having a diameter of 1 inch. In the step
a152, first, the substrate is reduced and annealed in a hydrogen atmosphere in the reaction
chamber. The flow rate of hydrogen is 2 sccm, the annealing temperature is 1000 ° C., and the
annealing time is 1 hour. Next, when methane gas with a flow rate of 25 sccm is introduced into
the reaction chamber, carbon atoms are deposited on the substrate to form graphene. In this
case, the pressure in the reaction chamber is maintained at 500 mtorr. The growth time of the
graphene is 10 to 60 minutes, preferably 30 minutes.
[0046]
In the step a153, the metal film provided with the graphene introduces hydrogen and methane
gas into the reaction chamber before being cooled to room temperature. In this embodiment, in
the cooling step, methane gas having a flow rate of 25 sccm and hydrogen having a flow rate of
2 sccm are introduced into the reaction chamber to maintain the pressure in the reaction
chamber at 500 mTorr. After the metal film is cooled for 1 hour, it is taken out from the reaction
chamber, and the graphene structure 38 is formed on one surface of the metal film.
05-05-2019
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[0047]
The carbon gas is a gas such as acetylene, methane, ethane or ethylene. The shielding gas is an
inert gas such as argon and nitrogen gas. The deposition temperature of the graphene is 800 °
C. to 1000 ° C. In this embodiment, since the method of manufacturing the graphene structure
38 is a chemical vapor deposition method, the graphene structure 38 can have a large area.
Therefore, the graphene structure 38 may be combined with the carbon nanotube structure 22
having a large area to form the graphene-carbon nanotube composite structure 2 having a large
area.
[0048]
After the carbon nanotube structure 22 is coated on the surface of the graphene structure 38
formed on one surface of the substrate opposite to the surface adjacent to the substrate, a
mechanical force is applied to make them integrated. The graphene-carbon nanotube composite
structure 2 can be obtained by etching and removing the substrate supporting the carbon
nanotube structure 22 and the graphene structure 38 with a corrosion liquid.
[0049]
The carbon nanotube structure 22 in the graphene-carbon nanotube composite structure 2 can
also be composed of a plurality of carbon nanotube wires. Referring to FIG. 12, the carbon
nanotube structure 22 includes a plurality of carbon nanotube wires 284. Specifically, a part of
the carbon nanotube wire 284 is defined as a first carbon nanotube wire, and another part of the
carbon nanotube wire 284 is defined as a second carbon nanotube wire. The first carbon
nanotube wires are parallel to one another, and the second carbon nanotube wires are also
parallel to one another. The plurality of first carbon nanotube wires and the plurality of second
carbon nanotube wires are crossed to form a network structure. The carbon nanotube structure
22 has a plurality of micropores 44. The distance between the two adjacent carbon nanotube
wires 284 is 10 μm to 1000 μm, preferably 100 μm to 500 μm. The dimensions of the
plurality of micropores 44 are 10 μm to 1000 μm, and preferably 100 μm to 500 μm.
[0050]
05-05-2019
17
The plurality of first carbon nanotube wires and the plurality of second carbon nanotube wires
may be non-twisted carbon nanotube wires or twisted carbon nanotube wires. Referring to FIG.
13, when the carbon nanotube wire is a non-twisted carbon nanotube wire, it comprises a
plurality of carbon nanotube segments (not shown) connected end to end. The carbon nanotube
segments have the same length and width. Furthermore, in each of the carbon nanotube
segments, a plurality of carbon nanotubes of the same length are arranged in parallel. The
plurality of carbon nanotubes are arranged parallel to the central axis of the carbon nanotube
wire. The length, thickness, uniformity and shape of the plurality of carbon nanotube segments
are not limited. The length of one non-twisted carbon nanotube wire is not limited, and its
diameter is 100 nm to 100 μm.
[0051]
Referring to FIG. 14, a twisted carbon nanotube wire can be formed by applying opposing forces
from opposite ends along the longitudinal direction of the non-twisted carbon nanotube wire.
Preferably, the twisted carbon nanotube wire comprises a plurality of carbon nanotube segments
(not shown) connected end to end. Furthermore, a plurality of carbon nanotubes of the same
length are arranged in parallel to each of the carbon nanotube segments. The length, thickness,
uniformity and shape of the carbon nanotube segment are not limited. The length of one twisted
carbon nanotube wire is not limited, and its diameter is 0.5 nm to 100 μm. Methods for
producing the carbon nanotube wire are disclosed in Patent Document 3 and Patent Document 4.
[0052]
The ratio of the area of the plurality of carbon nanotubes to the area of the plurality of
micropores in the graphene-carbon nanotube composite structure 2 is 1: 1000 to 1:10, but is 1:
100 to 1:10. preferable. Since the carbon nanotube structure 22 in the graphene-carbon
nanotube composite structure 2 is composed of a plurality of carbon nanotube wires, the size and
shape of the plurality of micropores 44 can be easily controlled.
[0053]
The graphene-carbon nanotube composite structure 2 has the following excellent points. First, in
05-05-2019
18
the graphene-carbon nanotube composite structure 2, a portion of the graphene structure 38 is
suspended with respect to the plurality of micropores 24 of the carbon nanotube structure 22, so
that the graphene-carbon is The nanotube composite structure 2 has excellent light
transmittance. Second, since a plurality of carbon nanotubes are arranged in an oriented manner
in the carbon nanotube structure 22, the carbon nanotube structure 22 has good conductivity.
Therefore, the graphene-carbon nanotube composite structure 2 has good conductivity. Third,
since the carbon nanotube structure 22 and the graphene structure 38 have excellent
mechanical strength and toughness, the graphene-carbon nanotube composite structure 2 has
excellent mechanical strength and toughness. Fourth, because a portion of the graphene
structure 38 having a low heat capacity per unit area is suspended with respect to the plurality
of micropores 24 of the carbon nanotube structure 22, it can be in contact with the surrounding
air. Therefore, the graphene-carbon nanotube composite structure 2 has a low heat capacity per
unit area.
[0054]
The electrical resistivity of the medium around the acoustic wave generator 102 is greater than
the electrical resistivity of the acoustic wave generator 102. On the other hand, since the heat
capacity per unit volume of the medium is large, the heat generated from the sound generator
102 can be conducted. The medium can be a gas or a liquid. For example, the gaseous medium is
air, and the liquid medium is one or more of a non-electrolytic solution, water or an organic
solvent. The electrical resistivity of the liquid medium is 0.01 Ω · m or more, and is preferably
pure water. In the present embodiment, the medium of the sound wave generator 102 is air.
[0055]
The thermoacoustic device 10 is electrically connected to an external circuit by the first electrode
104a and the second electrode 104b, and can generate an acoustic wave by transferring an
external signal. Since the thermoacoustic device 10 includes a graphene structure and the heat
capacity per unit area of the graphene structure is small, the pressure wave is generated in the
surrounding medium by the temperature wave generated by the sound wave generator 102. Can.
When a signal is transferred to the graphene structure of the sound wave generator 102, heat is
generated in the graphene structure by the signal intensity and / or the signal. The diffusion of
the temperature wave thermally expands the surrounding air to produce a sound. In the present
embodiment, the thermoacoustic apparatus 10 operates by an electro-thermal-sound conversion
system.
05-05-2019
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[0056]
The sound pressure level of the thermoacoustic device 10 is 50 dB, and its frequency response
range is 1 Hz to 100 KHz. The harmonic distortion of the thermoacoustic device 10 can be very
small, for example reaching as low as 3% in the range of 500 Hz to 40 KHz.
[0057]
Example 2 Referring to FIGS. 16 and 17, the thermoacoustic apparatus 20 of the present
example includes a sound wave generator 202, a heater 204, and a substrate 208. The difference
between the present embodiment and the first embodiment is that the thermoacoustic apparatus
20 of the present invention includes a substrate 208. The sound wave generator 202 is installed
on one surface of the substrate 208. The heater 204 includes a first electrode 204a and a second
electrode 204b. The first electrode 204a and the second electrode 204b are electrically
connected to the sound wave generator 202 so as to be separated by a predetermined distance.
In the present embodiment, the first electrode 204a and the second electrode 204b are disposed
on the surface of the sound wave generator 202 opposite to the surface adjacent to the substrate
208, and the sound wave generator 202 is opposed to the surface Parallel to two sides. The
shape, size and thickness of the substrate 208 are not limited. The substrate 208 is flat or
curved, and the material is a hard or flexible material having a certain strength. Preferably, the
substrate 208 has good thermal insulation and heat resistance, and its electrical resistivity is
greater than the electrical resistivity of the sound wave generator 202. Specifically, the material
of the substrate 208 is glass, ceramics, quartz, diamond, plastic, resin and wood.
[0058]
In the present embodiment, at least one through hole 208 a is formed in the substrate 208. The
relationship between the depth H1 of the through hole 208a and the thickness H2 of the
substrate 208 is represented by the following equation (1).
[0059]
H1 ≦ H2 (Equation 1)
05-05-2019
20
[0060]
If the depth of the through hole 208a is smaller than the thickness of the substrate 208, the
through hole 208a is a blind hole.
If the depth of the through hole 208a is equal to the thickness of the substrate 208, the through
hole 208a is a through hole. The shape of the cross section of the through hole 208a may be
circular, square, rectangular, triangular, polygonal or machined. When a plurality of through
holes 208 a are formed in the substrate 208, the distance between two adjacent through holes
208 a is 100 μm to 3 mm. In the present embodiment, a plurality of through holes 208 a are
uniformly formed in the substrate 208, and the cross-sectional shape of the single through hole
208 a is circular.
[0061]
The sound wave generator 202 is formed on one surface of the substrate 208 and is suspended
on the plurality of through holes 208a. In the present embodiment, a part of the sound wave
generator 202 is suspended above the plurality of through holes 208 a, and the other part is
directly installed on one surface of the substrate 208. Thus, the thermoacoustic generator 202 is
supported by the substrate 208.
[0062]
Example 3 Referring to FIG. 18, the thermoacoustic apparatus 30 includes a sound wave
generator 302, a heater 304, and a substrate 308. Compared to the second embodiment, at least
one groove 308 a is formed in the substrate 308 of the thermoacoustic apparatus 30 of the
present embodiment. The at least one groove 308 a is formed on one surface 308 b of the
substrate 308. The depth of the groove 308 a is smaller than the thickness of the substrate 308.
The groove 308a is a blind groove or a through groove. When the groove 308 a is a blind groove,
its length is smaller than the side L 3 of the substrate 308. When the groove 308 a is a through
groove, the length thereof is the same as the side L 3 of the substrate 308. The shape of the
groove 308a may be a rectangle, an arc, a polygon, or a circle. Referring to FIG. 19, when the
cross section along the longitudinal direction of the blind groove 308a is rectangular, the blind
groove 308a is defined as "rectangular blind groove 308a". Referring to FIG. 20, when the cross
section along the longitudinal direction of the blind groove 308a is a triangle, the blind groove
05-05-2019
21
308a is defined as "a triangular prism blind groove 308a". Referring to FIG. 18, in the present
embodiment, a plurality of rectangular blind grooves 308 a are uniformly installed on the surface
308 b of the substrate 308. The distance between two adjacent ones of the blind grooves 308a is
not limited.
[0063]
In the thermoacoustic apparatus 30, at least one groove 308 a is formed in the substrate 308.
Since the groove 308a can reflect the signal of the sound wave generator 302, the signal
intensity of the sound wave generator 302 is increased. The substrate 308 supports the sound
wave generator 302 and maximizes the contact area between the sound wave generator 302 and
the surrounding medium when the distance between two adjacent blind grooves 308 a
approaches zero. Can.
[0064]
In order to enhance the thermoacoustic effect of the sound wave generator 302, the depth of the
groove 308a is preferably 10 μm to 10 mm.
[0065]
Example 4 Referring to FIG. 21 and FIG.
Compared to the second embodiment, the thermoacoustic apparatus 40 of the present
embodiment includes a substrate 408 which is a network structure. The thermoacoustic device
40 includes a sound wave generator 402, a heater 404, and a substrate 408. The substrate 408
is a network structure, and includes a plurality of first linear structures 408 a and a plurality of
second linear structures 408 b. The plurality of first linear structures 408a and the plurality of
second linear structures 408b cross each other to form a network structure. When the plurality
of first linear structures 408a are parallel to each other and the plurality of second linear
structures 408b are parallel to each other, the plurality of first linear structures 408a may be in
the first direction L1. The plurality of second linear structures 408b extend along a second
direction L2. It is preferable that a distance between two adjacent first linear structures 408a is 0
to 1 cm, and a distance between two adjacent first linear structures 408b is 0 to 1 cm. In the
present embodiment, the plurality of first linear structures 408a are installed in parallel to each
other at equal intervals. The distance between two adjacent first linear structures 408a is 1 cm.
05-05-2019
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The plurality of second linear structures 408b are installed in parallel to each other at equal
intervals. The distance between two adjacent second linear structures 408b is 1 cm. The first
direction L1 and the second direction L2 intersect at an angle α (0 ° <α ≦ 90 °).
[0066]
The substrate 408 has a plurality of meshes 408c. The mesh 408c is formed by crossing the
plurality of first linear structures 408a and the plurality of second linear structures 408b with
each other. The mesh 408c is a quadrilateral, for example, a square, a rectangle or a rhombus.
The dimensions of the mesh 408c are determined by the distance between two adjacent first
linear structures 408a and the distance between two adjacent second linear structures 408b. In
the present embodiment, the mesh 408c is square, and its side length is 2 cm.
[0067]
The diameters of the plurality of first linear structures 408a and the plurality of second linear
structures 408b may be, but are not limited to, 10 μm to 5 mm, and the materials thereof may
be fibers, plastics, resins or insulation such as silicone. It is a material. Specifically, the plurality
of first linear structures 408a and the plurality of second linear structures 408b are made of one
or more of plant fibers, animal fibers, wood fibers, and mineral fibers, but have certain heat
resistance characteristics. It is preferable to use a flexible material such as nylon cord having
spanner, spandex. The plurality of first linear structures 408 a and the plurality of second linear
structures 408 b may be made of a conductive linear material covered with an insulating layer.
The conductive linear material is a metal wire or a linear carbon nanotube structure. The metal
wire is made of pure metal or alloy. The pure metal is aluminum, copper, tungsten, molybdenum,
gold, titanium, neodymium, palladium or cesium. The alloy is aluminum, copper, tungsten,
molybdenum, gold, titanium, neodymium, palladium, cesium, or both. The insulating layer is
resin, plastic, silicon dioxide or metal oxide. In the same embodiment, the structures and
materials of the plurality of first linear structures 408a and the plurality of second linear
structures 408b may be the same or different. In the present embodiment, the plurality of first
linear structures 408a and the plurality of second linear structures 408b are linear carbon
nanotube structures coated with silicon dioxide.
[0068]
05-05-2019
23
The linear carbon nanotube structure includes a plurality of carbon nanotube wires. The carbon
nanotube wire comprises a plurality of carbon nanotubes. The carbon nanotubes may be one or
more of single-walled carbon nanotubes, double-walled carbon nanotubes, and multi-walled
carbon nanotubes. In the present embodiment, the carbon nanotube wire is the same as the
carbon nanotube wire 284 in the carbon nanotube structure 22 (see FIG. 12).
[0069]
Since the substrate 408 of the thermoacoustic apparatus 40 of the present embodiment is the
network structure, the thermoacoustic apparatus 40 has the following excellent points. First,
since the substrate 408 is the network structure, the substrate 408 has good flexibility. When the
plurality of first linear structures 408 a and / or the plurality of second linear structures 408 b
are linear carbon nanotube structures coated with an insulating layer, the diameter of the linear
carbon nanotube structures is Because the size is small, the contact area between the sound wave
generator 402 and the surrounding air is increased, and the thermoacoustic effect of the
thermoacoustic device 40 is enhanced. Third, since the linear carbon nanotube structure has
good flexibility, the linear carbon nanotube structure is not damaged no matter how many times
it is bent, and the service life of the thermoacoustic device 40 is extended. be able to.
[0070]
When the substrate 408 is a single linear structure, the linear structure is bent several times to
form a network structure.
[0071]
Example 5 Referring to FIG.
Compared to the second embodiment, the thermoacoustic device 50 of the present embodiment
is different in that it includes the substrate 508 which is a carbon nanotube composite structure.
The sound wave generator 502 is installed on one surface of the substrate 508. The heater 504
includes a first electrode 504a and a second electrode 504b. The first electrode 504a and the
second electrode 504b are electrically connected to the sound wave generator 502 so as to be
separated by a predetermined distance. In the present embodiment, the first electrode 504a and
the second electrode 504b are disposed on the surface of the sound wave generator 502
opposite to the surface adjacent to the substrate 508, and the sound wave generator 502 is
05-05-2019
24
opposed Parallel to two sides. The shape, size and thickness of the substrate 508 are not limited.
The substrate 508 is flat or curved.
[0072]
The carbon nanotube composite structure comprises a carbon nanotube structure and an
insulating material (not shown). The carbon nanotube structure comprises a plurality of carbon
nanotubes. The insulating material is coated on the surfaces of the plurality of carbon nanotubes.
A plurality of carbon nanotubes are uniformly dispersed in the carbon nanotube structure. Each
of the carbon nanotubes is connected by an intermolecular force. In the carbon nanotube
structure, the plurality of carbon nanotubes are arranged in an oriented manner or not oriented.
The carbon nanotube structures are classified into two types of non-oriented carbon nanotube
structures and oriented carbon nanotube structures according to the arrangement of the plurality
of carbon nanotubes. In the non-oriented carbon nanotube structure in this embodiment, the
carbon nanotubes are arranged or entangled along different directions. In the oriented carbon
nanotube structure, the plurality of carbon nanotubes are arranged along the same direction.
Alternatively, in the oriented carbon nanotube structure, when the carbon nanotube structure is
divided into two or more regions, a plurality of carbon nanotubes in each region are arranged
along the same direction. In this case, the alignment directions of carbon nanotubes in different
regions are different. The carbon nanotube is a single-walled carbon nanotube, a double-walled
carbon nanotube, or a multi-walled carbon nanotube. When the carbon nanotube is a singlewalled carbon nanotube, the diameter is set to 0.5 nm to 50 nm, and when the carbon nanotube
is a double-walled carbon nanotube, the diameter is set to 1 nm to 50 nm, and the carbon
nanotube is a multilayer carbon In the case of nanotubes, the diameter is set to 1.5 nm to 50 nm.
The carbon nanotube structure may have a thickness of 0.5 nm to 100 μm. Adjacent carbon
nanotubes of the carbon nanotube structure are juxtaposed with a gap to form a plurality of
micropores. The diameter of the pores is set to 50 μm or less.
[0073]
The carbon nanotube structure is formed in the shape of a free-standing thin film. Here, a selfsupporting structure is a form which can utilize the said carbon nanotube structure
independently, without using a support material. That is, it means that the carbon nanotube
structure can be suspended by supporting the carbon nanotube structure from opposite sides
without changing the structure of the carbon nanotube structure.
05-05-2019
25
[0074]
Examples of the carbon nanotube structure of the present invention include the following (1) to
(3).
[0075]
(1) Drown-Structured Carbon Nanotube Film As shown in FIG. 5, the carbon nanotube structure
includes at least one carbon nanotube film 143a.
The carbon nanotube film is a drawn carbon nanotube film. The carbon nanotube film 143a is
obtained by extracting from the super-aligned carbon nanotube array. In the single carbon
nanotube film, a plurality of carbon nanotubes are connected end to end along the same
direction. That is, the single carbon nanotube film 143a includes a plurality of carbon nanotubes
whose ends in the longitudinal direction are connected by an intermolecular force. 5 and 6, a
single carbon nanotube film 143a includes a plurality of carbon nanotube segments 143b. The
plurality of carbon nanotube segments 143b are connected end to end by intermolecular force
along the length direction. Each carbon nanotube segment 143b includes a plurality of carbon
nanotubes 145 connected by intermolecular force in parallel to each other. The lengths of the
plurality of carbon nanotubes 145 are the same in the single carbon nanotube segment 143b.
Toughness and mechanical strength of the carbon nanotube film 143a can be enhanced by
immersing the carbon nanotube film 143a in an organic solvent. Since the heat capacity per unit
area of the carbon nanotube film immersed in the organic solvent is low, the thermoacoustic
effect can be enhanced. The carbon nanotube film 143a has a width of 100 μm to 10 cm and a
thickness of 0.5 nm to 100 μm.
[0076]
In the method of manufacturing the drawn carbon nanotube film, at least one carbon nanotube
film is stretched from the carbon nanotube array using a first step of providing the super-aligned
carbon nanotube array and a tool such as tweezers. And two steps. A detailed description is
published in Patent Document 2
[0077]
05-05-2019
26
The carbon nanotube structure may include a plurality of stacked carbon nanotube films. In this
case, the adjacent carbon nanotube films are bonded by an intermolecular force. The carbon
nanotubes in the adjacent carbon nanotube film cross each other at an angle of 0 ° to 90 °.
When the carbon nanotubes in the adjacent carbon nanotube film intersect at an angle of 0 ° or
more, a plurality of micro holes are formed in the carbon nanotube structure. Alternatively, the
plurality of carbon nanotube films may be juxtaposed without gaps.
[0078]
(2) Fluff Structure Carbon Nanotube Film The carbon nanotube structure includes at least one
carbon nanotube film. This carbon nanotube film is a fluff structured carbon nanotube film
(flocculated carbon nanotube film). Referring to FIG. 24, in the single carbon nanotube film, a
plurality of carbon nanotubes are entangled and arranged isotropically. In the carbon nanotube
structure, the plurality of carbon nanotubes are uniformly distributed. The plurality of carbon
nanotubes are arranged without orientation. The length of the single carbon nanotube is 100 nm
or more, preferably 100 nm to 10 cm. The carbon nanotube structure is formed in the shape of a
free-standing thin film. The plurality of carbon nanotubes are formed close to each other by
intermolecular force and mutually intertwined to form a carbon nanotube network. The plurality
of carbon nanotubes are arranged without being oriented to form many minute holes. Here, the
diameter of the single minute hole is 10 μm or less. Since the carbon nanotubes in the carbon
nanotube structure are arranged to be entangled with each other, the carbon nanotube structure
is excellent in flexibility and can be formed to be curved in an arbitrary shape. Depending on the
application, the length and width of the carbon nanotube structure can be adjusted. The
thickness of the carbon nanotube structure is 1 μm to 1 mm.
[0079]
In the method for producing the fluff structure carbon nanotube film, a first step of providing a
carbon nanotube material (a carbon nanotube which becomes a base of the fluff structure carbon
nanotube film), immersing the carbon nanotube material in a solvent, and A second step of
processing to form a fluff structure carbon nanotube structure, and a third step of filtering a
solution containing the fluff structure carbon nanotube structure to remove the final fluff
structure carbon nanotube structure And. A detailed description is given in Patent Document 3.
[0080]
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27
(3) Precid Structure Carbon Nanotube Film The carbon nanotube structure includes at least one
carbon nanotube film. The carbon nanotube film is a pressed carbon nanotube film. The plurality
of carbon nanotubes in the single carbon nanotube film may be arranged isotropically, arranged
along a predetermined direction, or arranged along different directions. The carbon nanotube
film has a sheet-like free-standing structure formed by pressing the carbon nanotube array by
applying a predetermined pressure by using a pressing tool, and tilting the carbon nanotube
array by pressure. is there. The arrangement direction of carbon nanotubes in the carbon
nanotube film is determined by the shape of the pressing device and the direction in which the
carbon nanotube array is pushed.
[0081]
Referring to FIG. 25, carbon nanotubes in the single carbon nanotube film are arranged without
orientation. The carbon nanotube film includes a plurality of carbon nanotubes arranged
isotropically. Adjacent carbon nanotubes attract and connect to each other by intermolecular
force. The carbon nanotube structure has planar isotropy. The carbon nanotube film is formed by
pressing the carbon nanotube array along a direction perpendicular to the substrate on which
the carbon nanotube array is grown, using a flat tool.
[0082]
Referring to FIG. 26, carbon nanotubes in a single carbon nanotube film are aligned and
arranged. The carbon nanotube film includes a plurality of carbon nanotubes arranged along the
same direction. When simultaneously pressing the carbon nanotube array along the same
direction using a pressing device having a roller shape, a carbon nanotube film including carbon
nanotubes aligned in basically the same direction is formed. In addition, when simultaneously
pressing the carbon nanotube array along different directions by using a pressing device having
a roller shape, a carbon nanotube film including carbon nanotubes arranged in selective
directions along the different directions. Is formed.
[0083]
The degree of tilt of the carbon nanotubes in the carbon nanotube film is related to the pressure
applied to the carbon nanotube array. The carbon nanotubes in the carbon nanotube film and the
05-05-2019
28
surface of the carbon nanotube film form an angle α, and the angle α is 0 ° or more and 15 °
or less. Preferably, carbon nanotubes in the carbon nanotube film are parallel to the surface of
the carbon nanotube film. The greater the pressure, the greater the degree of inclination. The
thickness of the carbon nanotube film is related to the height of the carbon nanotube array and
the pressure applied to the carbon nanotube array. That is, as the height of the carbon nanotube
array increases and the pressure applied to the carbon nanotube array decreases, the thickness
of the carbon nanotube film increases. Conversely, the smaller the height of the carbon nanotube
array and the greater the pressure applied to the carbon nanotube array, the smaller the
thickness of the carbon nanotube film. Patent Document 5 discloses a method of producing the
presidated carbon nanotube film.
[0084]
In order to maintain electrical insulation between the carbon nanotube structure and the sound
wave generator 502, the insulating layer is disposed on the surface of the carbon nanotube
structure adjacent to the sound wave generator 502. In addition, by coating the insulating layer
on the surface of each carbon nanotube in the carbon nanotube structure, a carbon nanotube
composite structure having a plurality of micropores is formed. In this case, a part of the sound
wave generator 502 is suspended with respect to the plurality of fine holes 24, and the other
part is directly installed on the surface of the insulating layer one.
[0085]
Example 6 Referring to FIGS. 27 and 28, the thermoacoustic apparatus 60 of the present
example includes a substrate 608, a heater 604, and a sound wave generator 602. The heater
604 includes a plurality of first electrodes 604 a and a plurality of second electrodes 604 b. The
plurality of first electrodes 604 a and the plurality of second electrodes 604 b are each
electrically connected to the sound wave generator 602.
[0086]
The plurality of first electrodes 604 a and the plurality of second electrodes 604 b are spaced
apart and alternately disposed on one surface of the substrate 608. The sound wave generator
602 is disposed on the surface of the plurality of first electrodes 604 a and the plurality of
second electrodes 604 b opposite to the surface adjacent to the substrate 608, and a part of the
05-05-2019
29
sound wave generator 602 is The substrate 608 is suspended. That is, a plurality of gaps 601 are
formed by the substrate 608, the plurality of first electrodes 604 a, the plurality of second
electrodes 604 b, and the sound wave generator 602. The distance between the adjacent first
and second electrodes 604a and 604b may be the same or different, but is preferably the same.
The distance between the adjacent first and second electrodes 604a and 604b is preferably, but
not limited to, 10 μm to 1 cm.
[0087]
The substrate 608 is used to support the plurality of first electrodes 604 a and the plurality of
second electrodes 604 b. The substrate 608 is made of an insulating material having good
insulating properties or a low conductivity material, and its shape and size are not limited. In the
present embodiment, the substrate 608 is made of materials such as glass, resin and ceramics. In
the present embodiment, the substrate 608 is a square glass plate having a side length of 4.5 cm
and a thickness of 1 mm.
[0088]
The single gap 601 is defined by the substrate 608, one of the first electrodes 604 a, one of the
second electrodes 604 b and the sound wave generator 602. The height of the gap 601 is related
to the height of the first electrode 604a and the second electrode 604b. In the present
embodiment, the heights of the first electrode 604a and the second electrode 604b are 1 μm to
1 cm, and preferably 15 μm.
[0089]
The first electrode 604a and the second electrode 604b may be formed in a layered, rod-like,
strip-like or lump-like shape, and their cross sections may be circular, square, trapezoidal,
triangular or polygonal. The first electrode 604 a and the second electrode 604 b are fixed to one
surface of the substrate 608 by bolts or an adhesive. In order to prevent heat generated from the
sound wave generator 602 from being absorbed by the first electrode 604 a and the second
electrode 604 b, the heat of the sound wave generator 602 with the first electrode 604 a and the
second electrode 604 b The contact area is preferably small. The first electrode 604a and the
second electrode 604b are thread-like or band-like, and the material is any one kind of
conductive material such as metal, conductive adhesive, conductive paste, ITO, carbon nanotube
05-05-2019
30
or carbon fiber . In the present embodiment, the first electrode 604a and the second electrode
604b may be linear carbon nanotube structures. The structure of the linear carbon nanotube
structure is the same as the structure of the linear carbon nanotube structure in Example 4.
[0090]
The thermoacoustic device 60 further includes a lead 610 of the first electrode and a lead 612 of
the second electrode. The lead wire 610 of the first electrode and the lead wire 612 of the
second electrode are electrically connected to the first electrode 604a and the second electrode
604b, respectively. The thermoacoustic device 60 is electrically connected to an external circuit
by the lead wire 610 of the first electrode and the lead wire 612 of the second electrode. As a
result, the electrical resistance of the sound wave generator 602 is reduced, so that the
thermoacoustic effect of the sound wave generator 602 can be enhanced.
[0091]
In this embodiment, the plurality of first electrodes 604 a and the plurality of second electrodes
604 b may support the sound wave generator 602. In this case, the thermoacoustic device 60
may not include the substrate 608.
[0092]
In the present embodiment, the first electrode 604a and the second electrode 604b are threadlike silver electrodes formed by printing conductive silver paste. The thermoacoustic device 60
includes four of the first electrodes 604 a and four of the second electrodes 604 b. The four first
electrodes 604 a and the four second electrodes 604 b are equally spaced and alternately
disposed on one surface of the substrate 608. The length of each of the first electrode 604 a and
the second electrode 604 b is 3 cm, and the height thereof is 15 μm. The distance between the
adjacent first electrode 604a and the second electrode 604b is 5 mm.
[0093]
In the thermoacoustic apparatus 60, the sound wave generator 602 is suspended by the plurality
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of first electrodes 604a and the plurality of second electrodes 604b. As a result, the contact area
between the sound wave generator 602 and the surrounding air is increased, and the
thermoacoustic effect of the thermoacoustic device 60 is enhanced.
[0094]
Example 7 Referring to FIGS. 29 and 30, the thermoacoustic apparatus 70 of the present
example includes a substrate 708, a heater 704, and a sound wave generator 702. The heater
704 includes a plurality of first electrodes 704 a and a plurality of second electrodes 704 b. The
first electrode 704 a and the second electrode 704 b are electrically connected to the sound
wave generator 702. The sound wave generator 702 is formed of a graphene structure. The
difference between the present embodiment and the seventh embodiment is that the
thermoacoustic device 70 of the present invention includes at least one spacer 714 between the
adjacent first electrode 704a and the second electrode 704b.
[0095]
The spacer 714 can be fixed to the surface of the substrate 708 with a bolt or an adhesive. When
the spacer 714 and the substrate 708 are integrally formed, the spacer 714 and the substrate
708 may be made of the same material. The shape of the spacer 714 is, for example, spherical,
thread-like or band-like. In order that the thermoacoustic device 70 has a good thermoacoustic
effect, the contact system between the spacer 714 and the substrate 708 is preferably point
contact or line contact.
[0096]
In the present embodiment, the material of the spacer 714 is, for example, an insulating material
such as glass, ceramics, resin, or a conductive material such as metal, alloy, or ITO. When the
spacer 714 is made of a conductive material, the spacer 714 is kept electrically insulated from
the first electrode 704a and the second electrode 704b. Preferably, the spacers 714 are parallel
to the first and second electrodes 704a and 704b, respectively. The height of the spacer 714 is
not limited, but preferably 10 μm to 1 cm. In the present embodiment, the spacer 714 is a silver
thread formed by silk screen printing, and is disposed parallel to the first electrode 704a and the
second electrode 704b. The height of the spacer 714 is 20 μm, which is the same as the height
of the first electrode 704 a and the second electrode 704 b.
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[0097]
The sound wave generator 702 is disposed on the surface of the spacer 714, the first electrode
704a, and the second electrode 704b opposite to the surface adjacent to the substrate 708. The
sound wave generator 702 is spaced apart from the substrate 708 by the spacer 714, the first
electrode 704a, and the second electrode 704b. A space 701 is formed by the sound wave
generator 702, the first electrode 704a or the second electrode 704b, the spacer 714, and the
substrate 708. The distance between the sound wave generator 702 and the substrate 708 is
preferably 10 μm to 1 cm in order to prevent the generation of a standing wave in the sound
wave generator 702 and to have a good thermoacoustic effect. In the present embodiment, since
the height of the spacer 714, the first electrode 704a and the second electrode 704b is 20 μm,
the distance between the sound wave generator 702 and the substrate 708 is 20 μm.
[0098]
(Example 8) Referring to FIG. 31, the thermoacoustic apparatus 80 of this example includes a
first heater 804, a second heater 806, a substrate 808, a first sound wave generator 802a, and a
second sound wave. And a generator 802b.
[0099]
The substrate 808 includes a first surface (not shown) and a second surface (not shown), and its
shape, size and thickness are not limited.
The first surface and the second surface are flat surfaces, curved surfaces or uneven surfaces. In
the present embodiment, the substrate 808 is a rectangular structure, and the first surface and
the second surface face each other. Further, a plurality of through holes 808 a are formed in the
substrate 808. The through holes 808 a are disposed in parallel to one another and penetrate the
substrate 808.
[0100]
The first sound wave generator 802a is disposed on the first surface of the substrate 808, and at
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least a portion of the first sound wave generator 802a is suspended by the through hole 808a.
The second sound wave generator 802b is disposed on the second surface of the substrate 808,
and at least a portion of the second sound wave generator 802b is suspended by the through
hole 808a. The first sound wave generator 802a is formed of a graphene-carbon nanotube
composite structure, and the second sound wave generator 802b is formed of a graphene-carbon
nanotube composite structure or a carbon nanotube structure. The structure of the carbon
nanotube structure is the same as the structure of the carbon nanotube structure in Example 5.
[0101]
The first heater 804 includes a first electrode 804a and a second electrode 804b. The first
electrode 804 a and the second electrode 804 b are electrically connected to the sound wave
generator 802 at a predetermined distance apart. In the present embodiment, the first electrode
804a and the second electrode 804b are respectively disposed on the surface of the sound wave
generator 802a opposite to the surface adjacent to the first surface of the substrate 808, and the
sound wave generator Parallel to two opposite sides of 802. The second heater 806 includes a
first electrode 804a and a second electrode 804b. The first electrode 804 a and the second
electrode 804 b are electrically connected to the sound wave generator 806 at a predetermined
distance. In the present embodiment, the first electrode 804a and the second electrode 804b are
respectively disposed on the surface of the sound wave generator 802b opposite to the surface
adjacent to the second surface of the substrate 808, and the sound wave generator Parallel to
two opposite sides of 802.
[0102]
In the present embodiment, since the thermoacoustic apparatus 80 includes the first sound wave
generator 802a and the second sound wave generator 802b, the thermoacoustic apparatus 80 is
configured by the first sound wave generator 802a and the second sound wave generator 802b.
The sound generated from the thermoacoustic device 80 can be widely propagated. In the
thermoacoustic device 80, any one thermoacoustic device or two thermoacoustic devices of the
first acoustic wave generator 802a and the second acoustic wave generator 802b generate
acoustic waves, so the application range thereof is expanded. Furthermore, if one thermoacoustic
device fails, the other thermoacoustic device can be operated. Thereby, the working life of the
thermoacoustic device 80 can be extended.
[0103]
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Example 9 Referring to FIG. Compared with the eighth embodiment, the thermoacoustic
apparatus 90 of the present embodiment is different in that it is a multifaceted thermoacoustic
apparatus. The thermoacoustic apparatus 90 of this embodiment includes a substrate 908, four
sound wave generators 902, and four heat generators 904. In the present embodiment, the
substrate 908 is rectangular, and four of the six surfaces are uneven. The four sound wave
generators 902 are respectively installed on the four uneven surfaces. In the four sound wave
generators 902, at least one sound wave generator 902 comprises a graphene-carbon nanotube
composite structure, and the other sound wave generator 902 comprises a graphene-carbon
nanotube composite structure or a carbon nanotube structure be able to.
[0104]
Each of the heaters 904 includes a first electrode 904a and a second electrode 904b. The first
electrode 904 a and the second electrode 904 b are electrically connected to the sound wave
generator 902 at a predetermined distance. In the present embodiment, the first electrode 904 a
and the second electrode 904 b are disposed on the surface of the sound wave generator 902
opposite to the surface adjacent to the substrate 908, and the sound wave generator 902 is
opposed Parallel to two sides.
[0105]
Since the thermoacoustic device 90 is a multi-faceted thermoacoustic device, it can transfer
sound in different directions.
[0106]
Tenth Embodiment Referring to FIG.
Compared with the second embodiment, the heater 1004 of the present embodiment is different
in that it is an electromagnetic wave signal device such as a laser. When the electromagnetic
wave signal 1020 from the heater 1004 is transferred to the sound wave generator 1002, the
sound wave generator 1002 generates a sound wave.
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[0107]
The heat generator 1004 may be installed opposite to the sound wave generator 1002 at
intervals, or may be installed corresponding to the substrate 1008 via the substrate 1008. In the
present embodiment, the heater 1004 is a laser, and is disposed to face the sound wave
generator 1002 with a gap. The laser beam emitted from the laser passes through the substrate
1008 and is transferred to the sound wave generator 1002.
[0108]
The electromagnetic wave signal 1020 from the heater 1004 is received by the sound wave
generator 1002 and radiated as heat. Since the graphene structure of the sound wave generator
1002 has a small heat capacity of a unit area, pressure waves can be generated in the
surrounding medium by the temperature wave generated by the sound wave generator 1002.
When the electromagnetic wave signal 1020 is transferred to the graphene structure of the
sound wave generator 1002, heat is generated in the graphene structure by signal intensity and /
or signal. The diffusion of the temperature wave thermally expands the surrounding air to
produce a sound.
[0109]
The thermoacoustic device of the present invention includes a graphene-carbon nanotube
composite structure. Since the graphene graphene-carbon nanotube composite structure has
excellent mechanical strength and toughness, it is possible to provide the graphene-carbon
nanotube composite structure in a desired shape and size, which results in a large number of
desired It is possible to obtain thermoacoustic devices of shape and size. The thermoacoustic
apparatus can be used for electronic devices such as an acoustic system, a mobile phone, an MP3
player, an MP4 player, a TV, and a computer. The thermoacoustic apparatus may be installed in
the housing of the electronic device or on the outer surface of the housing. Furthermore, it may
have the same power source or the same processor as the thermoacoustic device and other
electronic components in the thermoacoustic device. It is connected to the electronic device by a
wireless system such as Bluetooth or a wired system such as a signal line.
[0110]
2 Graphene-carbon nanotube composite structure 10, 20, 30, 40, 50, 60, 70, 80, 90, 100
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Thermoacoustic device 102, 202, 302, 402, 502 Sound wave generator 602, 702, 802, 902,
1002 sound wave generator 104, 204, 304, 404, 504 heater 604, 704, 804, 904, 1004 heater
104a, 204a, 304a, 404a, 504a first electrode 604a, 704a, 804a, 904a, 1004a first electrode
104b, 204b, 304b, 404b, 504b Second electrode 604b, 704b, 804b, 904b, 1004b Second
electrode 143a Carbon nanotube film 143b, 282 Carbon nanotube segment 145 Carbon
nanotube 208, 3 8, 408, 608, 708, 808, 908, 1008 Substrate 208a, 808a Through Hole 22
Carbon Nanotube Structure 24, 44 Micropore 26 Carbon Nanotube Band Structure 28 Carbon
Nanotube Film 284 Carbon Nanotube Wire 286 Carbon Nanotube Array 308a Groove 308b
Surface 38 Graphene structure 408a first linear structure 408b second linear structure 408c
mesh 601 gap 610 lead of first electrode 612 lead of second electrode 714 spacer 802a first
acoustic wave generator 802b second acoustic wave generation 804 First heater 806 Second
heater 1020 Electromagnetic wave signal
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