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JP2010050974

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This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
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DESCRIPTION JP2010050974
The present invention provides a carbon nanotube-based speaker. A speaker of the present
invention includes a housing and at least one sound wave generator installed in the housing. The
sound wave generator includes a carbon nanotube structure. The carbon nanotube structure has
a free standing structure. The heat capacity per unit area of the carbon nanotube structure is 2
× 10 J / cm · K or less. [Selected figure] Figure 1
スピーカー
[0001]
The present invention relates to speakers, and more particularly to speakers based on carbon
nanotubes.
[0002]
Conventional speakers are of two types: passive speakers and active speakers.
An active speaker is a speaker incorporating an amplifier. The passive speaker is a speaker that is
connected to an external amplifier without using an amplifier. Many of the speaker products for
audio systems that use a combination of favorite products for each part. Speaker products for
personal computers often have active speakers with built-in amplifiers.
05-05-2019
1
[0003]
In general, a speaker includes a housing (e.g., a housing, a box, etc.) and a sound wave generator
installed in the housing. The housing is made of wood, ceramic, plastic, resin or the like. The
sound generator is used to convert an electrical signal to sound pressure.
[0004]
According to the principle of operation, there are many types of sound wave generator such as
dynamic sound wave generator, magnetic sound wave generator, electrostatic sound wave
generator, and piezoelectric sound wave generator. The various sound wave generators all
produce sound waves by mechanical vibration, ie, realize electro-mechanical force-sound
conversion. Here, a dynamic sound wave generator is widely used.
[0005]
Referring to FIG. 21, the conventional passive speaker 10 includes a dynamic acoustic wave
generator 100 and a housing 110. The sound wave generator 100 is installed in the case 110
adjacent to one side of the case 110. The sound wave generator 100 includes a voice coil (not
shown), a magnet (not shown), and a cone (not shown). The voice coil is disposed between the
magnets as a conductive component. When a current is supplied to the voice coil, the cone
vibrates and the pressure fluctuation of air continuously occurs by the interaction of the
electromagnetic field by the voice coil and the magnetic field by the magnet, so that a sound
wave can be generated. However, the dynamic sound generator 100 relies on the action of the
magnetic field.
[0006]
Since the early nineties, nanomaterials representing carbon nanotubes (see Non-Patent
Document 1) have attracted people's attention due to their uniqueness and nature. In recent
years, with the further research of carbon nanotubes and nanomaterials, the possibilities of its
application have gradually expanded. For example, since carbon nanotubes have unique
electromagnetics, optics, mechanics, chemistry, and other properties, many studies have been
reported for applications in fields such as field emission electron sources, sensors, and new types
05-05-2019
2
of optical materials. However, the prior art has not been applied to the field of detecting signals
as a device in which carbon nanotubes emit sound.
[0007]
Sumio Iijima, "Helical Microtubules of Graphitic Carbon", Nature, vol. 353, p56 Kaili Jiang,
Qunqing Li, Shoushan Fan, "Spinning continuous carbon nanotube yarns", Nature, vol. 419,
p.801
[0008]
In order to solve the above problems, the present invention is to provide a carbon nanotubebased speaker independently of the action of a magnetic field.
[0009]
The speaker of the present invention includes a housing and at least one sound wave generator
disposed in the housing.
The sound wave generator includes a carbon nanotube structure.
[0010]
The carbon nanotube structure has a free standing structure.
[0011]
The heat capacity per unit area of the carbon nanotube structure is 2 × 10 <-4> J / cm <2> · K or
less.
[0012]
In the carbon nanotube structure, the plurality of carbon nanotubes are arranged in an oriented
manner or not oriented.
[0013]
The carbon nanotube structure has at least one carbon nanotube film.
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[0014]
The single carbon nanotube film is any one kind of a drone structure carbon nanotube film, an
ultralong structure carbon nanotube film, a presid structure carbon nanotube film, or a fluff
structure carbon nanotube film.
[0015]
The speaker comprises at least two electrodes.
The at least two electrodes are separated by a predetermined distance and are respectively
electrically connected to the sound wave generator.
[0016]
Compared to the prior art, the loudspeaker of the present invention has the following advantages.
First, since the speaker of the present invention includes a carbon nanotube structure, the
structure is simple and light and compact can be realized as compared with the conventional
speaker.
Second, the speaker of the present invention heats the carbon nanotube structure to generate an
acoustic wave, and therefore, it is not necessary to use a magnet.
Third, since the carbon nanotube structure has a small heat capacity per unit area, a large
specific surface area, and a high rate of heat exchange, sound can be generated favorably.
Fourth, since the carbon nanotube structure is thin, it is possible to manufacture a transparent
speaker.
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[0017]
It is a schematic diagram of the speaker in Example 1 of this invention.
It is a SEM photograph of the carbon nanotube film in Example 1 of this invention. It is a
schematic diagram of the carbon nanotube segment in Example 1 of this invention. It is a SEM
photograph of the carbon nanotube film in Example 1 of this invention. It is a photograph of the
carbon nanotube structure of the fluff structure filtered. It is a scanning electron micrograph of
the segment of the carbon nanotube film of this invention. It is a SEM photograph of the piece of
the carbon nanotube film in Example 1 of the present invention. It is a SEM photograph of the
carbon nanotube wire in Example 1 of this invention. It is a SEM photograph of the twisted
carbon nanotube wire in Example 1 of the present invention. It is a schematic diagram of textiles
which consist of a plurality of carbon nanotube films and / or carbon nanotube wires in Example
1 of the present invention. It is a schematic diagram of the sound wave generator of the speaker
in Example 1 of this invention. It is a schematic diagram of the sound wave generator of the
speaker in Example 1 of this invention. It is a frequency response curve of the sound generator of
the speaker in Example 1 of this invention. It is a block diagram of the circuit of the speaker in
Example 1 of this invention. It is a schematic diagram of the sound wave generator of the speaker
in Example 2 of this invention. It is a schematic diagram of the sound wave generator of the
speaker containing a support body in Example 2 of this invention. It is a schematic diagram of
the sound wave generator of the speaker in Example 3 of this invention. It is a schematic diagram
of the sound wave generator of the speaker in Example 4 of this invention. It is a schematic
diagram of the sound wave generator of the speaker in Example 5 of this invention. It is a
schematic diagram of the sound wave generator of the speaker in Example 6 of this invention. It
is a schematic diagram of the conventional speaker.
[0018]
Hereinafter, embodiments of the present invention will be described with reference to the
drawings.
[0019]
Example 1 Referring to FIGS. 1-2, this example provides a sealable speaker 20.
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The sealed speaker 20 includes a housing 210 and at least one sound wave generator 200. The
housing 210 includes at least one first opening 212. The dimensions of the sound wave
generator 200 are the same as or larger than the first opening 212. By covering the sound wave
generator 200 on the first opening 212, the speaker 20 having the space for sealing can be
formed. In the present embodiment, the first opening 212 is formed in one side wall of the
housing 210, and the sound wave generator 200 is installed in the housing 210 so as to be
covered by the opening 212. Thus, air can pass through the sound wave generator 200.
[0020]
The housing 210 may be made of wood, bamboo, carbon fiber, glass, diamond, quartz, ceramic,
plastic, resin or the like. Furthermore, the housing 210 can also include a sound absorbing
material.
[0021]
The sound wave generator 200 includes a carbon nanotube structure 202. The carbon nanotube
structure 202 has a large specific surface area (for example, 50 m <2> / g or more). The heat
capacity per unit area of the carbon nanotube structure 202 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. Furthermore, a metal layer can be
formed on the surface of the carbon nanotube structure. A plurality of carbon nanotubes are
uniformly dispersed in the carbon nanotube structure. The plurality of carbon nanotubes are
connected by intermolecular force. The carbon nanotube structure preferably includes metal type
carbon nanotubes. 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 oriented 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 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
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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.
[0022]
When the carbon nanotube structure 202 is a flat plate type, its thickness is set to 0.5 nm to 1
mm. When the carbon nanotube structure 202 is linear, its diameter is set to 0.5 nm to 1 mm.
[0023]
Examples of the carbon nanotube structure 202 of the present invention include the following
(1) to (6).
[0024]
(1) Drought Structure Carbon Nanotube Film The carbon nanotube structure includes at least one
carbon nanotube film 143a shown in FIG.
The carbon nanotube film is a drawn carbon nanotube film. The carbon nanotube film 143a is
obtained by drawing from a super-aligned carbon nanotube array (see Non-Patent Document 2).
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. Referring to FIGS. 2 and 3, the 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.
[0025]
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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.
[0026]
The method of manufacturing the carbon nanotube film includes the following steps.
[0027]
The first step provides a carbon nanotube array.
The carbon nanotube array is a super aligned carbon nanotube array (see Super Aligned Array of
Carbon Nanotubes, Non-Patent Document 2), and a method of manufacturing the super aligned
carbon nanotube array employs a chemical vapor deposition method. The manufacturing method
includes the following steps. In step (a), a flat substrate is provided, which is any one of a P-type
silicon substrate, an N-type silicon substrate and a silicon substrate on which an oxide layer is
formed. In the present example, it is preferred to select a 4 inch silicon substrate. In step (b), a
catalyst layer is uniformly formed on the surface of the substrate. The material of the catalyst
layer is any one of iron, cobalt, nickel and alloys of two or more thereof. In step (c), the substrate
having the catalyst layer formed thereon is annealed with air at 700 ° C. to 900 ° C. for 30
minutes to 90 minutes. In step (d), the annealed substrate is placed in a reactor and heated with a
protective gas at a temperature of 500 ° C. to 740 ° C., and then a gas containing carbon is
introduced to react for 5 minutes to 30 minutes. To grow super aligned carbon nanotube arrays
(Non-Patent Document 2). The height of the carbon nanotube array is 100 micrometers or more.
The carbon nanotube array is composed of a plurality of carbon nanotubes that grow parallel to
one another and perpendicular to the substrate. The carbon nanotubes are partially intertwined
with one another because of their long length. By controlling the growth conditions, the carbon
nanotube array is free of impurities such as, for example, amorphous carbon and metal particles
as remaining catalyst.
[0028]
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8
In the present embodiment, as the gas containing carbon, for example, active hydrocarbons such
as acetylene, ethylene, methane and the like are selected, and ethylene is preferably selected. The
protective gas is nitrogen gas or inert gas, preferably argon gas.
[0029]
The carbon nanotube array provided by the present embodiment is not limited to being
manufactured by the above manufacturing method, and may be manufactured by an arc
discharge method or a laser evaporation method.
[0030]
In the second step, at least one carbon nanotube film is stretched from the carbon nanotube
array.
First, it has a plurality of carbon nanotube ends using tools such as tweezers. For example, a tape
having a certain width is used to have the ends of a plurality of carbon nanotubes. Next, the
plurality of carbon nanotubes are drawn at a predetermined speed to form a continuous carbon
nanotube film composed of a plurality of carbon nanotube segments.
[0031]
In the step of drawing out the plurality of carbon nanotubes, when the plurality of carbon
nanotubes are respectively detached from the base material, the carbon nanotube segments are
joined end to end by an intermolecular force to form a continuous carbon nanotube film .
[0032]
(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. 4, in the single carbon nanotube film, a plurality of carbon
05-05-2019
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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 freestanding thin film. Here, a self-supporting structure is a form which can utilize the said carbon
nanotube structure independently, without using a support body material. 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 0.5 nm to
1 mm.
[0033]
The method of manufacturing the carbon nanotube film includes the following steps.
[0034]
In the first step, a carbon nanotube raw material (a carbon nanotube to be the basis of a fluff
structured carbon nanotube film) is provided.
[0035]
The carbon nanotubes are peeled off from the substrate with a tool such as a knife to form a
carbon nanotube material.
The carbon nanotubes are intertwined to some extent.
In the raw material of the carbon nanotube, the length of the carbon nanotube is 100
micrometers or more, and preferably 10 micrometers or more.
[0036]
In the second step, the carbon nanotube material is immersed in a solvent, and the carbon
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nanotube material is treated to form a fluff structure carbon nanotube structure.
[0037]
After immersing the carbon nanotube material in the solvent, the carbon nanotube is formed into
a fluff structure by ultrasonic dispersion, high intensity stirring, vibration or the like.
The solvent is water or a volatile organic solvent. The ultrasonic dispersion method is applied to
a solvent containing carbon nanotubes for 10 to 30 minutes. Since the carbon nanotubes have a
large specific surface area and a large intermolecular force is generated between the carbon
nanotubes, the carbon nanotubes are respectively entangled and formed into a fluff structure.
[0038]
In the third step, the solution containing the fluff structure carbon nanotube structure is filtered
to take out the final fluff structure carbon nanotube structure.
[0039]
First, provide a funnel on which filter paper is placed.
The solvent containing the fluff structure carbon nanotube structure is added to the funnel on
which the filter paper is placed, and left for a while to be dried, whereby the fluff structure
carbon nanotube structure is separated. Referring to FIG. 5, carbon nanotubes in the fluff carbon
nanotube structure are entangled with each other to form an irregular fluff structure.
[0040]
The separated carbon nanotube structure of the fluff structure is placed in a container, the
carbon nanotube structure of the fluff structure is developed into a predetermined shape, and a
predetermined pressure is applied to the expanded carbon nanotube structure of the fluff
structure, If the solvent remaining in the fluff structure carbon nanotube structure is heated or
the solvent evaporates spontaneously, a fluff structure carbon nanotube film is formed.
05-05-2019
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[0041]
The thickness and area density of the fluff structure carbon nanotube film can be controlled by
the area where the fluff structure carbon nanotube structure is developed.
That is, in the fluff structure carbon nanotube structure having a certain volume, the thickness
and the surface density of the fluff structure carbon nanotube film decrease as the developed
area increases.
[0042]
In addition, a fluff structure carbon nanotube film is formed using a microporous membrane and
an air-pumping funnel. Specifically, a microporous membrane and an air pump funnel are
provided, a solvent containing the fluff structure carbon nanotube structure is added to the air
pump funnel through the microporous membrane, and the air pump funnel is bled and dried.
Then, a fluff structure carbon nanotube film is formed. The microporous membrane has a smooth
surface. In the microporous membrane, the diameter of a single micropore is 0.22 micrometers.
Since the microporous membrane has a smooth surface, the carbon nanotube film can be easily
peeled off from the microporous membrane. Furthermore, since the air is applied to the fluff
structure carbon nanotube film by using the air pump, it is possible to form a uniform fluff
structure carbon nanotube film.
[0043]
When the carbon nanotube structure includes only one sheet of the carbon nanotube film, both
ends of the carbon nanotube in the carbon nanotube film are electrically connected to the first
electrode and the second electrode, respectively. When the carbon nanotube structure includes at
least two stacked plural carbon nanotube films, an angle α between carbon nanotubes in
adjacent carbon nanotube films is 0 ° to 90 °. Both ends of the carbon nanotubes in at least
one of the carbon nanotube films are electrically connected to the first electrode and the second
electrode, respectively.
[0044]
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(3) Carbon Nanotube Film Segment The carbon nanotube structure includes one carbon
nanotube film segment. Referring to FIG. 6, carbon nanotubes in the carbon nanotube film
segment are parallel to each other and arranged along a predetermined direction. In the carbon
nanotube film segment, the length of at least one carbon nanotube is the same as the entire
length of the carbon nanotube film segment. Thus, one dimension of the carbon nanotube film
segment is limited by the length of the carbon nanotube. The carbon nanotube structure may
include a plurality of stacked carbon nanotube film segments. In this case, the adjacent carbon
nanotube film segments are bonded by an intermolecular force. The thickness of the carbon
nanotube film segment is 0.5 nm to 100 μm.
[0045]
The method for producing a carbon nanotube film segment comprises: providing a substrate;
providing a substrate with a second step of depositing at least one strip-like catalyst layer; and
depositing at least one carbon by the CVD method. A third step of growing a nanotube array, and
a fourth step of tilting the carbon nanotube array along a direction parallel to the surface of the
substrate to form at least one carbon nanotube film segment. The detailed description is
published in Japanese Patent Application No. 2009-128147.
[0046]
(4) Ultralong Structure Carbon Nanotube Film The carbon nanotube structure includes at least
one carbon nanotube film. The carbon nanotube film is an ultra-long carbon nanotube film.
Referring to FIG. 7, the single carbon nanotube film includes a plurality of carbon nanotubes
having substantially the same length. In the single carbon nanotube film, the plurality of carbon
nanotubes are uniformly juxtaposed along the same direction. The thickness of the single carbon
nanotube film is 10 nm to 100 μm. The plurality of carbon nanotubes are arranged in parallel
on the surface of the plurality of carbon nanotube films, and are arranged in parallel to one
another. Adjacent ones of the carbon nanotubes are spaced apart at a predetermined distance.
The distance is 0 to 5 μm. When the distance is 0 μm, adjacent carbon nanotubes are
connected by an intermolecular force. The length of each of the carbon nanotubes in the carbon
nanotube film is the same as the length of the carbon nanotube film. The length of the single
carbon nanotube is 1 cm or more, and preferably 1 cm to 30 cm. That is, the length of the carbon
nanotube is ultra-long. Furthermore, each of the carbon nanotubes 145 is free of knots. In the
present embodiment, the carbon nanotube film has a thickness of 10 μm. The length of the
single carbon nanotube 145 is 10 cm.
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[0047]
The method for manufacturing a carbon nanotube film includes a first step of providing a growth
apparatus including a reaction vessel, a second substrate having a catalyst layer on one surface,
and a first substrate installed in the reaction vessel of the growth apparatus. A second step,
introducing a gas containing carbon into the growth apparatus, and growing a carbon nanotube
on the second substrate, stopping the introduction of the gas containing carbon, and A fourth
step of attaching most of the first substrate to the first substrate, and replacing a new second
substrate having a catalyst with the second substrate on which the carbon And step. A detailed
description is published in Japanese Patent Application No. 2009-7005.
[0048]
(5) Presidated 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.
[0049]
The 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.
[0050]
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The carbon nanotubes in the 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.
[0051]
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
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 as 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.
[0052]
(6) Carbon Nanotube Wire The carbon nanotube structure includes at least one carbon nanotube
wire. The heat capacity of one carbon nanotube wire is 0 (not 0 included) to 2 × 10 <-4> J / cm
<2> · K, 5 × 10 <-5> J / cm <2> -It is preferable that it is K. The diameter of one carbon nanotube
wire is 4.5 nm to 1 cm. Referring to FIG. 8, the carbon nanotube wire comprises a plurality of
carbon nanotubes connected by intermolecular force. In this case, one carbon nanotube wire
(non-twisted carbon nanotube wire) includes a plurality of carbon nanotube segments (not
shown) connected end to end. The carbon nanotube segments have the same length and width.
Furthermore, a plurality of carbon nanotubes of the same length are arranged in parallel to each
of the carbon nanotube segments. The plurality of carbon nanotubes are arranged parallel to the
central axis of the carbon nanotube wire. In this case, the diameter of one carbon nanotube wire
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is 1 μm to 1 cm. Referring to FIG. 9, the carbon nanotube wire may be twisted to form a twisted
carbon nanotube wire. Here, the plurality of carbon nanotubes are arranged in a spiral shape
with the central axis of the carbon nanotube wire as an axis. In this case, the diameter of one
carbon nanotube wire is 1 μm to 1 cm. The carbon nanotube structure may be formed of any
one of the non-twisted carbon nanotube wire, the twisted carbon nanotube wire, or a
combination thereof.
[0053]
The method for forming the carbon nanotube wire utilizes a carbon nanotube film formed by
drawing from a carbon nanotube array. There are the following three methods for forming the
carbon nanotube wire. In the first type, the carbon nanotube film is cut at a predetermined width
along the longitudinal direction of the carbon nanotube in the carbon nanotube film to form a
carbon nanotube wire. In the second type, the carbon nanotube film may be immersed in an
organic solvent to shrink the carbon nanotube film to form a carbon nanotube wire. In the third
type, the carbon nanotube film is machined (for example, a spinning process) to form a twisted
carbon nanotube wire. Specifically, first, the carbon nanotube film is fixed to a spinning device.
Next, the spinning device is operated to rotate the carbon nanotube film to form a twisted carbon
nanotube wire.
[0054]
When the carbon nanotube structure 202 includes a plurality of carbon nanotube wires, the
plurality of carbon nanotube wires may be arranged in parallel or in a cross parallel weave or
may be twisted. A fabric comprising a plurality of carbon nanotube wires 146 is shown in FIG.
The first electrode and the second electrode are respectively installed at opposite ends of the
fabric. The first electrode and the second electrode are electrically connected to the carbon
nanotube wire 146.
[0055]
The sound wave generator 200 may be bonded to the housing 210 with a binder or be
incorporated into the housing 210 in a mechanical manner. Due to the large specific surface area
of the carbon nanotubes, the carbon nanotube structure 202 in the sound wave generator 200
has adhesiveness and is directly bonded to the housing 210.
05-05-2019
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[0056]
Further, the speaker 20 can include a fiber (not shown) for transferring an electrical signal. In
addition, the sound wave generator 200 can include a plurality of electrodes 204. The plurality
of electrodes 204 are separated by a predetermined distance and disposed on the surface of the
carbon nanotube structure 202. Each electrode 204 is connected to a length of the fiber to
transfer an electrical signal from the fiber to the carbon nanotube structure 202. A conductive
adhesive layer (not shown) is provided between the plurality of electrodes 204 and the sound
wave generator 200 in order to electrically connect the plurality of electrodes 204 and the sound
wave generator 200. It can also be done. The conductive adhesive layer may be disposed on the
surface of the sound wave generator 200. The conductive adhesive layer is made of silver paste.
[0057]
When the carbon nanotubes in the carbon nanotube structure 202 are arranged along the same
direction, one electrode 204 is connected to each end of one carbon nanotube. That is, the
carbon nanotubes are arranged in parallel in the direction from one electrode 204 to another
electrode 204. When a voltage is applied to the electrode 204, the carbon nanotube structure
202 converts electricity into heat. The thermal temperature wave changes the air density around
the carbon nanotube structure 202 to generate a sound wave.
[0058]
Referring to FIG. 11, when the carbon nanotube structure 202 is square, a length of the electrode
204 is equal to or longer than a length of one side of the carbon nanotube structure 202. When
the carbon nanotube structure 202 includes a drawn carbon nanotube, both ends of the carbon
nanotube in the carbon nanotube structure 202 are connected to different electrodes 204,
respectively.
[0059]
Referring to FIG. 12, when the carbon nanotube structure 202 is circular, one electrode 204 is
05-05-2019
17
installed along the edge of the carbon nanotube structure 202, while the other electrode 204 has
the carbon nanotube structure. It is placed at the center of the body 202. The carbon nanotubes
in the carbon nanotube structure 202 are arranged radially along the direction from the center
to the edge of the carbon nanotube structure 202. The electrode 204 is made of any one of
metal, conductive adhesive, carbon nanotube, and ITO.
[0060]
The electrode 204 may support the carbon nanotube structure 202 when it is a metal rod. Since
the carbon nanotube structure 202 has adhesiveness, the carbon nanotube structure 202 can be
directly bonded to the electrode 204. Furthermore, the electrodes 204 are respectively
connected to the two ends of the signal input device by conductive wires (not shown) to receive
the amplified signals.
[0061]
A conductive adhesive layer (not shown) may be disposed between the carbon nanotube
structure 202 and the electrode 204 in order to connect the carbon nanotube structure 202 and
the electrode 204 well. The adhesion layer may be disposed on the surface of the carbon
nanotube structure 202. In the present embodiment, the conductive adhesive layer is made of
silver paste.
[0062]
Of course, it is also possible to connect the carbon nanotube structure 202 directly to a signal
input device without using the electrode 204.
[0063]
The carbon nanotube structure 202 used for the sound wave generator 200 includes a plurality
of carbon nanotubes, and the heat capacity of the unit area is small. be able to.
Transferring a signal (eg, an electrical signal) to the sound generator 200 generates heat in the
sound generator 200 due to the signal strength and / or the signal. The diffusion of the
05-05-2019
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temperature wave thermally expands the surrounding air to produce a sound. In contrast to this,
the principle of generating sound by pressure waves generated by mechanical vibration of the
diaphragm in the conventional speaker is largely different. If the input signal is an electrical
signal, the sound generator 200 operates according to an electro-thermal-sound conversion
scheme, but if the input signal is an optical signal, the sound generator 200 is photo-thermal Operate by the sound conversion system.
[0064]
FIG. 13 is a frequency response curve of the speaker 20 in Example 1 of the present invention.
The sound wave generator 200 of the speaker 20 includes the carbon nanotube structure 202
including a single drone carbon nanotube film (30 mm in length and width). In this case, a 50 V
AC electrical signal is provided to the speaker 20. In order to detect the performance of the
speaker 20, a microphone is set apart from the speaker 20 at a distance of 5 cm and opposed to
one side of the speaker 20. It can be understood from FIG. 13 that the frequency response range
of the speaker 20 is wide and the sound pressure level is high. The sound pressure level of the
speaker 20 is 50 dB to 105 dB. When a voltage of 4.5 W is applied to the speaker 20, the
frequency response range of the speaker 20 is 1 Hz to 100 KHz. The harmonic distortion of the
speaker 20 is very small, for example, can reach only 3% in the range of 500 Hz to 40 KHz.
[0065]
The carbon nanotube structure 202 includes five carbon nanotube wire structures, and each of
the carbon nanotube wire structures includes one carbon nanotube wire. The distance between
adjacent carbon nanotube wire structures is 1 cm, and the diameter of a single carbon nanotube
wire structure is 50 μm. In this case, a 50 V AC electrical signal is provided to the speaker 20.
The sound pressure level of the speaker 20 is 50 dB to 95 dB. When a voltage of 4.5 W is applied
to the speaker 20, the frequency response range of the carbon nanotube structure 202 is 100 Hz
to 100 KHz.
[0066]
Furthermore, an audio crossing filter 230 may be installed in the speaker 20. Referring to FIG.
14, the audio crossing filter 230 includes a plurality of input ends (not shown) and an output end
(not shown). The plurality of output ends are respectively separated and connected to the
05-05-2019
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corresponding sound wave generator 200. Audio electrical signals are transferred from the input
to the audio crossover filter 230. The audio crossover filter 230 converts the audio electrical
signal into a plurality of bands such as intermediate frequency, high frequency and low
frequency. Audio electrical signals in different bands are transferred to different sound wave
generators 200 (eg, tweeters, woofers).
[0067]
Furthermore, when the speaker 20 is an active speaker, an amplification circuit 240 and a power
circuit 250 are provided in the housing 210 of the speaker 20. The power circuit 250 and the
amplifier circuit 240 are electrically connected. The power circuit 250 drives the amplifier circuit
240 such that the amplifier circuit 240 amplifies an audio electrical signal. The amplification
circuit 240 is coupled to the sound wave generator 200. When the amplifier circuit 240 is
electrically connected to the audio cross filter 230, the input audio electrical signal is amplified
by the amplifier circuit 240 and transferred to the audio cross filter 230, thereby the sound wave
generator 200. Transferred to When the speaker 20 is a passive speaker, the speaker is
electrically connected to an amplifier provided outside the housing 210.
[0068]
Example 2 Referring to FIG. 15, the present example provides a bass reflex speaker 30. The
speaker 30 includes a housing 310 and at least one sound generator 300. The at least one sound
wave generator 300 is disposed in the housing 310. The sound wave generator 300 includes a
carbon nanotube structure 302 and at least two electrodes 304. The at least two electrodes 304
are electrically connected to the carbon nanotube structure 302 at a predetermined distance
from each other.
[0069]
The bass reflex type speaker 30 of the present embodiment has the following differences
compared to the sealed speaker 20 of the first embodiment. A duct 316 is installed in the
housing 310 of the bass reflex type speaker 30 of this embodiment. The duct 316 is connected
to the housing 310. Furthermore, the housing 310 preferably includes at least one first opening
312 and at least one second opening 314. The second opening 314 is disposed at one end of the
duct 316. The sound generator 300 may cover the first opening 312.
05-05-2019
20
[0070]
The inside and the outside of the housing 310 can be penetrated by the second opening 314 and
the duct 316. The duct 316 and the housing 310 may be formed as a Helmholtz resonator. The
resonant frequency of the resonator is determined by the air in the housing 310 and the air in
part of the duct 316.
[0071]
Referring to FIG. 16, the sound wave generator 300 may be spaced apart from the first opening
312 by a predetermined distance. In this case, the sound wave generator 300 may be installed in
the housing 310 by the support 318. A portion of the sound wave generator 300 is suspended
by forming an opening (not shown) in the support 318.
[0072]
Example 3 Referring to FIG. 17, this example provides a labyrinth speaker 40. The labyrinth
speaker 40 includes a housing 410 and at least one sound generator 400. The at least one sound
wave generator 400 is installed in the housing 410. The sound generator 400 includes a carbon
nanotube structure 402 and at least two electrodes 404. The at least two electrodes 404 are
electrically connected to the carbon nanotube structure 402 at a predetermined distance from
each other.
[0073]
The labyrinth type speaker 40 of the present embodiment is different from the sealed type
speaker 20 of the first embodiment in the following points. In the housing 310 of the labyrinthtype speaker 40 of the present embodiment, a plurality of divided portions 416 are provided.
Furthermore, the housing 410 preferably includes at least one first opening 412 and at least one
second opening 414. By installing the plurality of divided parts 416 in the housing 410, an area
between the sound wave generator 400 and the second opening 414 is provided in the labyrinth
area. Sound may pass from the labyrinth region to the exterior of the housing 410. The sound
05-05-2019
21
wave generator 400 can cover the first opening 412, but the sound wave generator 400 and the
first opening 412 can be separated by a predetermined distance.
[0074]
Example 4 Referring to FIG. 18, this example provides a passive radiator speaker 50. The passive
radiator speaker 50 includes a housing 510 and at least one sound generator 500. The at least
one sound wave generator 400 is installed in the housing 410. The sound wave generator 500
includes a carbon nanotube structure 502 and at least two electrodes 504. The at least two
electrodes 504 are electrically connected to the carbon nanotube structure 502 at a
predetermined distance from each other.
[0075]
The passive radiator speaker 50 of the present embodiment is different from the sealed speaker
20 of the first embodiment in the following points. At least one passive radiator 516 is installed
in the housing 510 of the passive radiator type speaker 50 of the present embodiment.
Furthermore, the housing 510 preferably includes at least one first opening 512 and at least one
second opening 514. The passive radiator 516 is installed on the side wall of the housing 510
where the opening 514 is formed, corresponding to the second opening 514. The passive
radiator 516 is a cone of a dynamic speaker and includes a diaphragm (paper, resin, fiber, carbon
fiber, or a combination thereof). Alternatively, the first opening 512 may be coated by the sound
wave generator 500, but the sound wave generator 500 and the first opening 512 may be
separated by a predetermined distance.
[0076]
Example 5 Referring to FIG. 19, this example provides a horn-type speaker 60. The horn-type
speaker 60 includes a housing 610 and at least one sound generator 600. The at least one sound
wave generator 600 is disposed in the housing 610. The sound wave generator 600 includes a
carbon nanotube structure 602 and at least two electrodes 604. The at least two electrodes 604
are electrically connected to the carbon nanotube structure 602 at a predetermined distance
from each other.
05-05-2019
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[0077]
The following differences from the horn-type speaker 60 of the present embodiment are as
compared with the sealed-type speaker 20 of the first embodiment. In the housing 610 of the
horn type speaker 60 of this embodiment, one horn 616 is installed. The horn 616 has a first end
6162 and a second end 6164. The first end 6162 is larger than the second end 6164.
Furthermore, the housing 610 preferably includes at least one first opening 612. The second end
6164 of the horn 616 is placed in the housing 610 with the first end 6162 of the horn 616
corresponding to the first opening 612. The sound wave generator 600 coats the second end
6164 of the horn 616.
[0078]
Example 6 Referring to FIG. 20, this example provides a speaker 70. The speaker 70 includes a
housing 710 and at least one sound generator 700. The at least one sound wave generator 700
is installed in the housing 710. The sound generator 700 includes a carbon nanotube structure
702 and at least two electrodes 704. The at least two electrodes 704 are electrically connected to
the carbon nanotube structure 702 at a predetermined distance from each other.
[0079]
The speaker 70 of this embodiment has the following differences as compared with the sealed
speaker 20 of the first embodiment. In the housing 710 of the speaker 70 of this embodiment,
one cone 716 is installed. The cone 716 has a first end 7162 and a second end 7164. The first
end 7162 is larger than the second end 7164. The cone 716 is a cone of a dynamic speaker and
includes a diaphragm (paper, resin, fiber, carbon fiber, or a combination thereof). Furthermore,
the housing 710 preferably includes at least one first opening 712. The second end 7164 of the
horn 716 is placed in the housing 710 with the first end 7162 of the cone 716 corresponding to
the first opening 712. The sound generator 700 coats the second end 7164 of the cone 716.
[0080]
Reference Signs List 10 speaker 100 sound generator 110 housing 143a carbon nanotube film
143b carbon nanotube segment 145 carbon nanotube 146 carbon nanotube wire 20 speaker
200 sound generator 202 carbon nanotube structure 204 electrode 210 housing 230 audio
crossing filter 240 amplification circuit 250 power circuit Reference Signs List 30 speaker 300
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sound wave generator 302 carbon nanotube structure 304 electrode 310 housing 312 first
opening 314 second opening 316 duct 318 support 40 speaker 400 sound generator 402
carbon nanotube structure 404 electrode 410 housing 412 first opening 414 Second aperture
416 division 50 speaker 500 sound generator 502 carbon nanoti Bore structure 504 electrode
510 case 512 first opening 516 passive radiator 60 speaker 600 sound wave generator 602
carbon nanotube structure 604 electrode 610 case 612 first opening 616 horn 6162 first end
6164 second end 70 speaker 700 acoustic wave generator 702 carbon nanotube structure 704
electrode 710 housing 712 first opening 716 cone 7162 first end 7164 second end
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