JP5270460B2 - Thermoacoustic device - Google Patents

Abstract

The invention relates to a sounding device comprising an electromagnetic wave signal input device and a sounding element, wherein the sounding element and the electromagnetic wave signal input device are arranged at intervals; the sounding element comprises at least one carbon nano tube film, and the carbon nano tube film includes a plurality of carbon nano tubes which are parallel to each other;and the electromagnetic wave signal input device transmits an electromagnetic wave signal to the carbon nano tube film, thus the carbon nano tube film emits heat by absorbing the electromagnetic wavesignal so as to heat an air medium to send sound waves.

Description

  The present invention relates to a thermoacoustic apparatus and a sound transmission system using the same, and more particularly to a thermoacoustic apparatus using carbon nanotubes and a sound transmission system using the same.

  In general, the acoustic device includes a signal device and a sound wave generator. The signal device transmits a signal to the sound wave generator (for example, a speaker). The speaker can convert an electrical signal into sound as an electroacoustic transducer.

  Depending on the principle of operation, speakers are classified into various types such as dynamic speakers, magnetic speakers, electrostatic speakers, and piezoelectric speakers. The various types of speakers all generate sound waves by mechanical vibration, that is, realize electrical-mechanical force-sound conversion. Here, dynamic speakers are widely used.

  Referring to FIG. 36, the conventional dynamic speaker 100 includes a voice coil 102, a magnet 104, and a cone 106. The voice coil 102 is installed between the magnets 104 as a conductive component. When a current is supplied to the voice coil 102, the cone 106 vibrates due to the interaction between the electromagnetic field generated by the voice coil 102 and the magnetic field generated by the magnet 104, and air pressure fluctuations continuously occur. it can.

  However, since the dynamic speaker 100 depends on the action of a heavy magnet and a magnetic field, the structure of the dynamic speaker 100 is complicated. In addition, the magnet 104 of the dynamic speaker 100 has a problem of adversely affecting an electronic device disposed near the speaker. Further, since the dynamic speaker 100 operates according to the input condition of the electric signal, there is a problem that the dynamic speaker 100 cannot be operated when the electric signal is not provided.

  The thermoacoustic phenomenon is a phenomenon in which sound and heat are involved, and has two aspects, energy conversion and energy transport. When a signal is transferred to the thermoacoustic device, heat is generated in the thermoacoustic device and propagated to the surrounding medium. Sound waves can be generated due to thermal expansion and pressure waves caused by the propagated heat.

H. D. Arnold, I.D. B. Crandall, “The thermophone as a precision source of sound”, Phys. 1917, Vol. 10, pp. 22-38, Alexander Graham Bell, “Selenium and the Photophone”, Nature, September 1880) Kaili Jiang, Quung Li, Shuushan Fan, “Spinning continuous carbon nanotube yarns”, Nature, 2002, vol. 419, p. 801

Non-Patent Document 1 discloses a thermophone manufactured by a thermoacoustic phenomenon. 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 capacity per unit area of the platinum piece is very high, a thermophone using the platinum piece has a problem that sound is very weak when used outdoors.

  The photoacoustic effect is a phenomenon in which sound and light are involved. That is, a molecule that absorbs light energy releases heat and generates an acoustic wave (dense wave) due to volume expansion due to the heat. . The photoacoustic effect was first disclosed in Non-Patent Document 2.

  Currently, the photoacoustic effect is used in the technical field of material analysis. For example, a photoacoustic spectroscopic device using a photoacoustic effect and a photoacoustic microscope are widely used in the technical field of material analysis. Conventionally, a photoacoustic spectrum device includes a light source (eg, a laser device), a sealed sample chamber, and a signal detector (eg, a microphone). A gas, liquid, or solid sample is placed in the sample chamber, and the laser is irradiated to the sample by the laser device. In this case, the sample generates sound pressure due to the photoacoustic effect. When irradiating lasers of different frequencies, different materials have different maximum absorption capabilities for the laser. The maximum absorption capacity can be detected using a microphone. However, most of the sound pressures are very weak and cannot be detected by the human ear, so it is necessary to install a complicated sensor. Therefore, there are limitations on the application of the speaker.

  The present invention provides a lightweight thermoacoustic apparatus in order to solve the above problems. The thermoacoustic apparatus of the present invention does not depend on a magnetic field and can generate sound without depending on mechanical vibration.

  The thermoacoustic device of the present invention includes an electromagnetic signal device and a sound wave generator including a carbon nanotube structure. The electromagnetic signal device transmits an electromagnetic signal to the carbon nanotube structure. The carbon nanotube structure includes at least one carbon nanotube film. The single carbon nanotube film includes a plurality of carbon nanotubes arranged in parallel to each other.

  The thermoacoustic device of the present invention includes an electromagnetic signal device and a sound wave generator including a carbon nanotube structure. The electromagnetic signal device transmits an electromagnetic signal to the carbon nanotube structure. The carbon nanotube structure converts the electromagnetic signal into heat, causing a thermoacoustic effect in the medium. The carbon nanotube structure includes at least one carbon nanotube film. The single carbon nanotube film includes a plurality of carbon nanotubes arranged in parallel to each other.

The carbon nanotube structure has a heat capacity per unit area of 0 (not including 0) to 2 × 10 ⁻⁴ J / cm ² · K.

  In the single carbon nanotube film, the length of the single carbon nanotube is 1 cm to 30 cm.

  In the single carbon nanotube film, the plurality of carbon nanotubes have the same length.

  In the single carbon nanotube film, the plurality of carbon nanotubes are arranged in parallel along the same direction.

  The length of each carbon nanotube in the carbon nanotube film is the same as the length of the carbon nanotube film.

  The electromagnetic signal device includes an optical fiber.

  A modulation device is installed between the electromagnetic signal device and the sound wave generator.

  The sound wave generator is provided with a support for supporting the sound wave generator.

  Compared with the prior art, the thermoacoustic device of the present invention has the following advantages. First, since the thermoacoustic device of the present invention includes a carbon nanotube structure, the structure is simpler than conventional speakers and can be reduced in weight and size. Second, since the thermoacoustic apparatus of the present invention generates sound waves by heating the carbon nanotube structure, 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 heat exchange rate, sound can be generated satisfactorily. Fourth, since the carbon nanotube structure is thin, a transparent acoustic device can be manufactured. Fifth, since the thermoacoustic device of the present invention can transmit an electromagnetic signal in a vacuum atmosphere, the thermoacoustic device of the present invention can be used in an extreme environment. The thermoacoustic device of the present invention can be used under conditions where an electric signal cannot be received (for example, a combustible environment).

It is a schematic diagram of the thermoacoustic apparatus in Example 1 of this invention. It is a SEM photograph of the carbon nanotube film in Example 1 of the present invention. It is a schematic diagram of the carbon nanotube segment in Example 1 of the present invention. It is a SEM photograph of the carbon nanotube film in Example 1 of the present invention. It is a SEM photograph of the segment 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 the present 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 the textile fabric which consists of a some carbon nanotube film in Example 1 of this invention or / and a carbon nanotube wire. It is a frequency response curve of the thermoacoustic apparatus in Example 1 of this invention. It is a schematic diagram of the thermoacoustic apparatus in Example 1 of this invention. It is a schematic diagram of the thermoacoustic apparatus in Example 2 of this invention. It is a schematic diagram of the thermoacoustic apparatus in Example 3 of this invention. It is a schematic diagram of the thermoacoustic apparatus in Example 4 of this invention. It is a schematic diagram of the thermoacoustic apparatus in Example 5 of this invention. It is a schematic diagram of the thermoacoustic apparatus in Example 6 of this invention. It is a circuit diagram in Example 6 of the present invention. It is a graph which shows the bias voltage which uses the power amplifier in Example 6 of this invention. It is a schematic diagram of the thermoacoustic apparatus in Example 6 of this invention. It is a schematic diagram of the thermoacoustic apparatus in Example 6 of this invention. It is a schematic diagram of the thermoacoustic apparatus in Example 7 of this invention. It is a schematic diagram of the textile fabric which consists of a plurality of carbon nanotube films or / and carbon nanotube wires in Example 7 of the present invention. FIG. 3 is a view showing that two carbon nanotube films shown in FIG. 2 are bonded to a frame portion. It is a relationship curve of the sound pressure and time of the thermoacoustic apparatus in Example 7 of this invention. It is a chart which shows the relationship between the sound pressure of the thermoacoustic apparatus in Example 7 of this invention, and an output. It is a chart which shows the relationship between the sound pressure of the thermoacoustic apparatus in Example 7 of this invention, and an output. It is a chart which shows the relationship between the sound pressure of the thermoacoustic apparatus in Example 7 of this invention, and an output. It is a chart which shows the relationship between the sound pressure of the thermoacoustic apparatus in Example 7 of this invention, and an output. It is a schematic diagram of the thermoacoustic apparatus in Example 8 of this invention. It is a schematic diagram of the thermoacoustic apparatus in Example 9 of this invention. It is a schematic diagram of the thermoacoustic apparatus in Example 10 of this invention. It is a schematic diagram of the thermoacoustic apparatus in Example 11 of this invention. It is a schematic diagram of the thermoacoustic apparatus in Example 12 of this invention. It is a top view of the thermoacoustic apparatus in Example 12 of this invention. It is a schematic diagram of the sound transmission system of the present invention. It is a chart of the sound wave generation method of the present invention. It is a schematic diagram of the conventional speaker.

  Embodiments of the present invention will be described below with reference to the drawings.

Example 1
Referring to FIG. 1, the thermoacoustic device 10 of the present invention includes a signal device 12, a sound wave generator 14, a first electrode 142, and a second electrode 144. The first electrode 142 and the second electrode 144 are each electrically connected to the sound wave generator 14 so as to be separated by a predetermined distance. The first electrode 142 and the second electrode 144 are each electrically connected to the signal device 12. The signal from the signal device 12 is transferred to the sound wave generator 14 by the first electrode 142 and the second electrode 144.

The sound wave generator 14 includes a carbon nanotube structure. The carbon nanotube structure has a large specific surface area (for example, 100 m ² / g or more). The heat capacity per unit area of the carbon nanotube structure is 0 (not including 0) to 2 × 10 ⁻⁴ J / cm ² · K, and preferably 0 (not including 0) to 1.7. × 10 ⁻⁶ J / cm ² · K, and in the present example, 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 needs to include metal-type carbon nanotubes. In the carbon nanotube structure, the plurality of carbon nanotubes are arranged with or without orientation. According to the arrangement method of the plurality of carbon nanotubes, the carbon nanotube structure is classified into two types: a non-oriented carbon nanotube structure and an oriented carbon nanotube structure. In the non-oriented carbon nanotube structure in the present 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 arrangement directions of the 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. When the carbon nanotube is a double-walled carbon nanotube, the diameter is set to 1 nm to 50 nm. In the case of a nanotube, the diameter is set to 1.5 nm to 50 nm.

  The carbon nanotube structure has a flat plate shape and a thickness of 0.5 nm to 1 mm. The smaller the specific surface area of the carbon nanotube structure, the higher the heat capacity per unit area of the carbon nanotube structure. The higher the heat capacity per unit area of the carbon nanotube structure, the lower the sound pressure of the thermoacoustic device.

  The carbon nanotube structure includes at least one carbon nanotube film 143a shown in FIG. The carbon nanotube film 143a is obtained by pulling out from a super aligned carbon nanotube array (see Non-Patent Document 3). In the single carbon nanotube film, a plurality of carbon nanotubes are connected to each other along the same direction. That is, the single carbon nanotube film includes a plurality of carbon nanotubes whose lengthwise ends are connected by intermolecular force. 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 to each other by an intermolecular force along the length direction. Each carbon nanotube segment 143b includes a plurality of carbon nanotubes 145 connected in parallel to each other by intermolecular force. In the single carbon nanotube segment 143b, the plurality of carbon nanotubes 145 have the same length. By soaking the carbon nanotube film 143a in an organic solvent, the toughness and mechanical strength of the carbon nanotube film 143a can be increased. Since the heat capacity per unit area of the carbon nanotube film immersed in the organic solvent is lowered, 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.

  The carbon nanotube structure may include a plurality of stacked carbon nanotube films. In this case, the adjacent carbon nanotube films are bonded by intermolecular force. The carbon nanotubes in the adjacent carbon nanotube films intersect each other at an angle of 0 ° to 90 °. When the carbon nanotubes in the adjacent carbon nanotube films intersect at an angle of 0 ° or more, a plurality of micropores are formed in the carbon nanotube structure. Alternatively, the plurality of carbon nanotube films may be juxtaposed without gaps.

  Alternatively, 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 arranged in parallel 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 to the surfaces of the plurality of carbon nanotube films, and are arranged in parallel to each other. Adjacent carbon nanotubes are separated and installed at a predetermined distance. The distance is 0 μm to 5 μm. When the distance is 0 μm, the adjacent carbon nanotubes are connected by intermolecular force. The length of each carbon nanotube 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. Further, each carbon nanotube 145 has no nodules. 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.

  The carbon nanotube structure includes at least one carbon nanotube film. Referring to FIG. 4, in the single carbon nanotube film, a plurality of carbon nanotubes are entangled and isotropically arranged. In the carbon nanotube structure, the plurality of carbon nanotubes are uniformly distributed. The plurality of carbon nanotubes are arranged without being oriented. The length of the single carbon nanotube is 100 nm or more, and preferably 100 nm to 10 cm. The carbon nanotube structure is formed in the shape of a self-supporting thin film. Here, the self-supporting structure is a form in which the carbon nanotube structure can be used independently without using a support material. The plurality of carbon nanotubes are close to each other by intermolecular force and entangled with each other to form a carbon nanotube net. 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 so as to be entangled with each other, the carbon nanotube structure is excellent in flexibility and can be formed to be bent into an arbitrary shape. Depending on the application, the length and width of the carbon nanotube structure can be adjusted. The carbon nanotube structure has a thickness of 0.5 nm to 1 mm.

  The carbon nanotube structure includes one carbon nanotube film segment. Referring to FIG. 5, all the carbon nanotubes in the segments of the carbon nanotube film are parallel to each other and aligned in a predetermined direction. In the segment of the carbon nanotube film, the length of at least one carbon nanotube is the same as the total length of the segment of the carbon nanotube film. Accordingly, 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 laminated carbon nanotube film segments. In this case, the adjacent segments of the carbon nanotube film are bonded by intermolecular force. The thickness of the segment of the carbon nanotube film is 0.5 nm to 100 μm.

The carbon nanotube structure includes at least one carbon nanotube wire. The heat capacity of one carbon nanotube wire is 2 × 10 ⁻⁴ J / cm ² · K or less, and preferably 5 × 10 ⁻⁵ J / cm ² · K. The diameter of one carbon nanotube wire is 4.5 nm to 1 cm. Referring to FIG. 6, the carbon nanotube wire includes a plurality of carbon nanotubes connected by intermolecular force. In this case, one 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. Further, a plurality of carbon nanotubes having the same length are arranged in parallel in 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 is 1 μm to 1 cm. Referring to FIG. 7, the carbon nanotube wire can be twisted to form a twisted carbon nanotube wire. Here, the plurality of carbon nanotubes are arranged in a spiral shape around the central axis of the carbon nanotube wire. In this case, the diameter of one carbon nanotube wire is 1 μm to 1 cm. The carbon nanotube structure may be any one of the non-twisted carbon nanotube wire, the twisted carbon nanotube wire, or a combination thereof.

  When the carbon nanotube structure includes a plurality of carbon nanotube wires, the plurality of carbon nanotube wires may be arranged in parallel, cross-woven, or twisted. FIG. 8 shows a fabric composed of a plurality of carbon nanotube wires 146. A first electrode 142 and a second electrode 144 are installed at opposite ends of the fabric. The first electrode 142 and the second electrode 144 are electrically connected to the carbon nanotube wire 146.

  Since the carbon nanotube structure is flexible, the carbon nanotube structure can be formed into various shapes, and the carbon nanotube structure is installed on the surface of a hard insulator or a flexible insulator (for example, a flag or cloth). can do. When the flag on which the carbon nanotube structure is installed flutters in the wind, it can be used as the sound wave generator 14. The cloth provided with the carbon nanotube structure can play music as a player such as MP3. Further, by using a cloth in which the carbon nanotube structure is installed, a physically handicapped person (for example, a hearing impaired person) can be helped.

  Even when a part of the carbon nanotube structure used for the sound wave generator 14 is broken, sound waves can be generated by the carbon nanotube structure. On the other hand, when the diaphragm or cone of a conventional speaker is damaged, sound waves cannot be generated.

  As shown in FIG. 1, the sound wave generator 14 of the present embodiment includes a carbon nanotube structure. The carbon nanotube structure includes a carbon nanotube film. In the carbon nanotube film, the carbon nanotubes are arranged along the same direction. The acoustic wave generator 14 has a length of 3 cm, a width of 3 cm, and a thickness of 50 nm. When the sound wave generator 14 is thin (thickness is 10 μm or less), the sound wave generator 14 has excellent transparency. Accordingly, by using the transparent sound wave generator 14, a transparent thermoacoustic device can be manufactured. The transparent thermoacoustic device can be installed on the surface of a mobile phone or LCD, for example. Or the said transparent thermoacoustic apparatus can be affixed on the surface of a picture. By using the transparent sound wave generator 14, the thermoacoustic device is excellent in that it is small and lightweight.

  The first electrode 142 and the second electrode 144 are made of a conductive material of metal, conductive adhesive, carbon nanotube, or ITO. In the present embodiment, the first electrode 142 and the second electrode 144 are rod-shaped metal electrodes. The sound wave generator 14 is electrically connected to the first electrode 142 and the second electrode 144, respectively. Since the carbon nanotube structure used for the sound wave generator 14 has adhesiveness, the sound wave generator 14 can be directly bonded to the first electrode 142 and the second electrode 144. Further, the first electrode 142 and the second electrode 144 are respectively connected to both ends of the signal device 12 by conductive wires 149.

  In order to satisfactorily electrically connect the first electrode 142 or the second electrode 144 and the sound wave generator 14, electrical conductivity is provided between the first electrode 142 or the second electrode 144 and the sound wave generator 14. An adhesive layer (not shown) can also be installed. The conductive adhesive layer may be installed on the surface of the sound wave generator 14. The conductive adhesive layer is made of a silver paste.

  The signal device 12 is one of an electric signal device, a direct current pulsation signal device, an alternating current device, and an electromagnetic wave signal device (for example, an optical signal device, a laser). The signal transferred from the signal device 12 to the sound wave generator 14 is, for example, an electromagnetic wave (for example, an optical signal), an electrical signal (for example, an alternating current, a direct current pulsation signal, an audio electrical signal) or a mixed signal thereof. is there. The signal is received by the carbon nanotube structure and emitted as heat. Since the pressure intensity of the surrounding medium (environment) changes due to heat radiation, a detectable signal can be generated. When the thermoacoustic device 10 is used for an earphone, the input signal is an AC electric signal or an audio electric signal. When the thermoacoustic apparatus 10 is used for a photoacoustic spectrum device, the input signal is an optical signal. In this embodiment, the signal device 12 is a photoacoustic spectrum, and the input signal is an electrical signal.

  The placement of the first electrode 142 and the second electrode 144 is selective with respect to the different types of the signal device 12. For example, when the signal from the signal device 12 is an electromagnetic wave or light, the signal device 12 can transfer the signal to the sound wave generator 14 without using the first electrode 142 and the second electrode 144. .

  In the signal device 12, the carbon nanotube structure of the sound wave generator 14 includes a plurality of carbon nanotubes, and has a small heat capacity per unit area. Therefore, the temperature wave generated by the sound wave generator 14 causes pressure on the surrounding medium. Vibration can be generated. When a signal (for example, an electrical signal) is transferred to the carbon nanotube structure of the sound wave generator 14, heat is generated in the carbon nanotube structure depending on the signal intensity and / or the signal. Due to the diffusion of the temperature wave, the surrounding air is thermally expanded and a sound is generated. This principle is greatly different from the principle of generating sound by pressure waves generated by mechanical vibration of a diaphragm in a conventional speaker. When the input signal is an electrical signal, the thermoacoustic device 10 operates according to an electrical-thermal-sound conversion method. When the input signal is an optical signal, the thermoacoustic device 10 -Operates according to the sound conversion method. The energy of the optical signal is absorbed by the sound wave generator 14 and radiated as heat. Since the pressure intensity of the surrounding medium (environment) changes due to the radiation of heat, a detectable signal can be generated.

  FIG. 9 is a frequency response curve of the thermoacoustic apparatus in Example 1 of the present invention. In this case, an AC electrical signal of 50V is provided to the carbon nanotube structure. In order to detect the performance of the thermoacoustic apparatus 10, a microphone is installed facing the one side of the sound wave generator 14 separated from the sound wave generator 14 by a distance of 5 cm. From FIG. 9, it can be understood that the thermoacoustic device 10 has a wide frequency response range and a high sound pressure level. The sound pressure level of the thermoacoustic device 10 is 50 dB to 105 dB. When a voltage of 4.5 W is applied to the thermoacoustic device 10, the frequency response range of the thermoacoustic device 10 is 1 Hz to 100 KHz. The harmonic distortion of the thermoacoustic device 10 is very small, for example, it can reach only 3% in the range of 500 Hz to 40 KHz.

  When the carbon nanotube structure of the thermoacoustic device 10 includes five carbon nanotube wires, the distance between adjacent carbon nanotube wires is 1 cm, and the diameter of one carbon nanotube wire is 50 μm. It is. When transferring an AC electric signal of 50 V to the carbon nanotube structure, the sound pressure level generated in the thermoacoustic device 10 is 50 dB to 100 dB. When a voltage of 4.5 W is applied to the thermoacoustic device 10, the frequency response range of the thermoacoustic device 10 is 100 Hz to 100 KHz.

  Furthermore, since the carbon nanotube structure has excellent mechanical strength and toughness, it is possible to provide the carbon nanotube structure in a desired shape and size. The thermoacoustic device 10 can be obtained. The thermoacoustic apparatus 10 can be used for, for example, an acoustic system, a mobile phone, MP3, MP4, a TV, a computer, and the like.

(Example 2)
Referring to FIG. 10, the thermoacoustic device 20 of the present embodiment includes a signal device 22, a sound wave generator 24, a first electrode 242, a second electrode 244, a third electrode 246, and a fourth electrode 248. ,including. The configuration, characteristics, and functions of the thermoacoustic device 20 of the present embodiment are the same as those of the thermoacoustic device 10 of the first embodiment. The difference between the present embodiment and the first embodiment is that the thermoacoustic apparatus 20 of the present embodiment includes four electrodes (first electrode 242, second electrode 244, third electrode 246, and fourth electrode 248). is there. The four electrodes have a rod shape and are separated from each other by a predetermined distance. The sound wave generator 24 is electrically connected to the four electrodes so as to surround the four electrodes. Further, the first electrode 242 and the third electrode 246 are electrically connected in parallel to one end of the signal device 22 through a first conductive line 249. The second electrode 244 and the fourth electrode 248 are electrically connected in parallel to the other end of the signal device 22 through a second conductive line 249 ′. Since the electrodes are connected in parallel to the signal device 22, the voltage applied to the thermoacoustic device 20 is low.

  Referring to FIG. 11, the four electrodes may be installed on the same plane. In this case, a plurality of electrodes can be installed in the thermoacoustic apparatus 20 without being limited to the four electrodes.

(Example 3)
Referring to FIG. 12, the thermoacoustic device 30 of this embodiment includes a signal device 32, a sound wave generator 34, a first electrode 342, and a second electrode 344. The configuration, characteristics, and functions of the thermoacoustic device 30 of the present embodiment are the same as those of the thermoacoustic device 10 of the first embodiment. The difference between the present embodiment and the first embodiment is that the thermoacoustic apparatus 20 of the present embodiment includes a support 36. The sound wave generator 34 is installed on the surface of the support 36. The shape of the support 36 is determined according to the shape of the sound wave generator 34. The support 36 is planar or / and curved. The support 36 is one of a screen, a wall, a desk, and a display. The sound wave generator 34 can be brought into contact with the support 36.

  The support 36 is made of a hard material such as diamond, glass, or quartz, or a flexible material such as plastic, resin, or fabric. The support 36 has a heat insulating property and cannot absorb the heat generated by the sound wave generator 34. Furthermore, it is preferable that the surface in contact with the support 36 and the sound wave generator 34 is provided rough. Thereby, the area which the said sound generator 34 and a surrounding catalyst contact can be increased. Since the carbon nanotube structure has a large specific surface area, the sound wave generator 34 can be directly bonded to the support 36.

  In order to connect the sound wave generator 34 and the support 36 satisfactorily, an adhesive layer (not shown) can be provided between the sound wave generator 34 and the support 36. The adhesive layer may be disposed on the surface of the sound wave generator 34. In this embodiment, the conductive adhesive layer is made of a silver paste.

  The first electrode 342 and the second electrode 344 are installed on the same surface of the sound wave generator 34, or are respectively installed on opposite surfaces of the sound wave generator 34. The thermoacoustic device 20 can be provided with a plurality of electrodes without being limited to the two electrodes. The signal device 32 is connected to the sound wave generator 34 by a conductive wire 349.

Example 4
Referring to FIG. 13, the thermoacoustic device 40 of the present embodiment includes a signal device 42, a sound wave generator 44, a support 46, a first electrode 442, a second electrode 444, a third electrode 446, A fourth electrode 448. The configuration, characteristics, and functions of the thermoacoustic device 30 of the present embodiment are the same as those of the thermoacoustic device 10 of the first embodiment. The difference between the present embodiment and the third embodiment is that the sound wave generator 44 is installed so as to surround the support 46. The support 46 has a three-dimensional or two-dimensional structure such as a cube, a cone, or a cylinder. In this embodiment, the support 46 is cylindrical, and the first electrode 442, the second electrode 444, the third electrode 446, and the fourth electrode 448 are separated from each other by a predetermined distance, and It is electrically connected to the sound wave generator 44. The system in which the first electrode 442, the second electrode 444, the third electrode 446, and the fourth electrode 448 are connected to the signal device 42 is the same as in the first embodiment. Of course, the present invention is not limited to the four electrodes, and a plurality of electrodes can be installed in the thermoacoustic device 40.

(Example 5)
Referring to FIG. 14, the thermoacoustic device 50 of this embodiment includes a signal device 52, a sound wave generator 54, a support 56, a first electrode 542, and a second electrode 544. The configuration, characteristics, and functions of the thermoacoustic device 50 of the present embodiment are the same as those of the thermoacoustic device 30 of the third embodiment. The difference between the present embodiment and the third embodiment is that a part of the sound wave generator 54 is installed on the support 56 to form a sound collection space from the sound wave generator 54 and the support 56. That is. The space is a closed space or an open space. The support 56 is U-shaped or L-shaped. The thermoacoustic device 50 may include two or more supports 56. The support 56 is one of wood, plastic, metal, and glass. Referring to FIG. 14, in this embodiment, the support 56 is L-shaped, and the sound wave generator 54 extends from the first end 562 of the support to the second end 564. A space for sound collection can be formed from 54 and the support 56. The first electrode 542 and the second electrode 544 are installed on the surface of the sound wave generator 54 and are electrically connected to the signal device 52. Thereby, since the sound generated by the sound wave generator 54 is reflected by the inner wall of the support 56, the acoustic function of the thermoacoustic device 50 can be enhanced.

(Example 6)
Referring to FIGS. 15 and 16, the thermoacoustic device 60 of the present embodiment includes a signal device 62, a sound wave generator 64, two electrodes 642, and a power amplifier 66. The configuration, characteristics, and functions of the thermoacoustic device 60 of the present embodiment are the same as those of the thermoacoustic device 10 of the first embodiment. The difference between the present embodiment and the first embodiment is that the thermoacoustic apparatus 60 of the present embodiment includes a power amplifier 66. The power amplifier 66 is electrically connected to the signal device 62. Further, the signal device 62 includes a signal output device (not shown), and the signal output device is electrically connected to the signal device 62. The power amplifier 66 can amplify the signal output from the signal device 62 and transfer it to the sound wave generator 64. The power amplifier 66 includes two output units 664 and an input unit 662. The input unit 662 is electrically connected to the signal device 62, and the output unit 664 is electrically connected to the sound wave generator 64.

  Referring to FIG. 17, when an alternating current is provided to the thermoacoustic device 60, the frequency of the output signal of the sound wave generator 64 can be about twice as high as the frequency of the input signal. This is because an alternating current flows through the sound wave generator 64, and the sound wave generator 64 is alternately heated with a positive current and a negative current, so that a double frequency temperature vibration and a double frequency sound pressure are generated. Therefore, when a conventional power amplifier (for example, a bipolar amplifier) is used, the output signal (human voice or music) is about twice that of the input signal, so it sounds strange.

  The power amplifier 66 can provide an amplified signal (eg, a voltage signal) and a bias voltage to the sound wave generator 64 to reduce the input signal. Referring to FIG. 16, the power amplifier 66 is a class A power amplifier, and includes a first resistor R1, a second resistor R2, a third resistor R3, a capacitor, and a triode. The triode includes a base B, an emitter E, and a collector C. The capacitor is connected to the signal output terminal of the signal device 62 and the base B of the triode. The DC voltage Vcc and the first resistor R1 are connected to the base B of the triode. The base B of the triode is connected to the second resistor R2. The emitter E is electrically connected to one output 664 of the power amplifier 66. The DC voltage Vcc is electrically connected to another output 664 of the power amplifier 66. The collector C is connected to the third resistor R3. Two output portions 664 of the power amplifier 66 are connected to the two electrodes 642, respectively. The resistors R2 and R3 are each grounded.

  A plurality of electrodes may be electrically connected to the sound wave generator 64. Adjacent electrodes are connected to different ends 664 of the power amplifier 66. When the electrodes are not installed, the two output portions 664 of the power amplifier 66 are electrically connected to the sound wave generator 64 by conductive wires.

  Referring to FIG. 15, in order to reduce the frequency of the signal from the signal device 62, a frequency reduction circuit 69 is installed. The frequency reduction circuit 69 can transfer the signal to the power amplifier 66 after, for example, reducing the signal frequency by half. The power amplifier 66 is a conventional power amplifier, for example, and does not provide the amplified voltage signal and bias voltage to the sound wave generator 64. The frequency reduction circuit 69 can be integrated with the power amplifier 66.

  18 and 19, the thermoacoustic device 60 further includes a plurality of sound wave generators 64 and a calibrator 68. The calibrator 68 is connected to the input part 662 or the output part 664 of the power amplifier 66. Referring to FIG. 18, when the calibrator 68 is connected to the output 664 of the power amplifier 66, the calibrator 68 divides the amplified signal from the power amplifier 66 into sub-signals of a plurality of frequency bands. The sub-signals are transferred to the plurality of sound wave generators 64, respectively. Referring to FIG. 19, when the calibrator 68 is connected to the input 662 of the power amplifier 66, the thermoacoustic device 60 includes a plurality of power amplifiers 66. The calibrator 68 divides the signal from the signal device 62 into sub-signals of a plurality of frequency bands, and transfers the sub-signals to the plurality of power amplifiers 66, respectively. Each power amplifier 66 corresponds to one sound wave generator 64.

(Example 7)
Referring to FIG. 20, the thermoacoustic device 70 of the present embodiment includes an electromagnetic signal device 712, a sound wave generator 714, a support 716, and a modulation device 718. The sound wave generator 714 is supported by the support 716. Alternatively, the sound wave generator 714 having a self-supporting structure can be installed without using the support 716. The electromagnetic signal device 712 is installed at a predetermined distance from the sound wave generator 714 and transmits an electromagnetic signal 720. The modulation device 718 is installed between the electromagnetic signal device 712 and the sound wave generator 714 and can modulate the density and / or frequency of the electromagnetic signal 720 from the electromagnetic signal device 712. The electromagnetic signal 720 modulated by the modulation device 718 is transmitted to the sound wave generator 714. The sound wave generator 714 is in contact with a surrounding medium.

  Similar to the first embodiment, the sound wave generator 714 of the present embodiment has good transparency and flexibility, so that the sound wave generator 714 can be installed in another device. The support 716 is one of a display device, a mobile phone, a computer, a resonance box, a door, a window, a projection screen, furniture, a fabric, an aircraft, and the like.

  The sound wave generator 714 includes a carbon nanotube structure. The carbon nanotube structure includes a plurality of carbon nanotube wires. The plurality of carbon nanotube wires are arranged in parallel to each other, or crossed, interwoven, or twisted. Referring to FIG. 21, the carbon nanotube structure is formed by interweaving the carbon nanotube wires of FIG. 6 or FIG. Of course, the carbon nanotube structure of FIG. 21 can be formed using a carbon nanotube film and / or a carbon nanotube wire structure. Since the thermoacoustic device 70 transmits signals using electromagnetic waves, it is not necessary to install electrodes on the sound wave generator 714.

  The support 716 may be the support 36 of the third embodiment or the support 46 of the fourth embodiment. All the sound wave generators 714 can be installed on the surface of the support 716. When the sound wave generator 714 has a self-supporting structure, the sound wave generator 714 is directly installed, or the periphery of the sound wave generator 714 is fixed to a frame portion, and other parts are suspended. The area where the suspended portion of the sound wave generator 714 contacts the surrounding medium is large. Referring to FIG. 22, the two carbon nanotube films shown in FIG. 2 are bonded to the frame portion 722. The two carbon nanotube films are bonded to each other at 90 °.

  The electromagnetic signal device 712 includes an electromagnetic signal generator (not shown). The electromagnetic signal generator generates electromagnetic waves of different densities and frequencies to produce the electromagnetic signal 720. The carbon nanotube structure may receive the electromagnetic signal 720 and convert electromagnetic energy into thermal energy. Since the heat capacity per unit area of the carbon nanotube structure is very low, the temperature of the carbon nanotube structure changes rapidly with the reception of the electromagnetic signal 720 under the same frequency condition, and heat waves To the other media. Therefore, by transmitting the electromagnetic signal 720, a surrounding medium (for example, ambient air) can be heated at the same frequency, and a pressure wave can be generated in the surrounding environment by a heat wave, and a sound wave can be generated. Since the thermoacoustic device 70 is operated by conversion of “light-heat-sound”, it is greatly different from a conventional speaker that is operated by mechanical vibration of a diaphragm. Since carbon nanotubes can uniformly absorb all electromagnetic spectra (eg, radio, far infrared, near infrared, ultraviolet, X-ray, gamma ray, high energy gamma ray), the electromagnetic spectrum of the electromagnetic signal 720 is: Includes radio, far infrared, near infrared, ultraviolet, X-ray, gamma ray, high energy gamma ray. In this embodiment, the electromagnetic signal 720 is an optical signal, and the frequency of the optical signal is in the range from the frequency of far infrared rays to the frequency of ultraviolet rays.

The average output density of the electromagnetic signal 720 is 1 μW / mm ^{2 to 20} W / mm ² . If the average output density of the electromagnetic signal 720 is too small, the surrounding medium cannot be heated. If the average power density of the electromagnetic signal 720 is too large, the carbon nanotube structure may be damaged. In this embodiment, the electromagnetic signal generator is a pulse laser generator (for example, an infrared diode laser). Further, the electromagnetic device 70 includes a focusing element (not shown) such as a lens. The focusing element can reduce the average output density of the electromagnetic signal 720 by focusing the electromagnetic signal 720 generated by the sound wave generator 714.

  The sound wave generator 714 can transmit the electromagnetic signal 720 to the sound wave generator 714 at an arbitrary angle. In this embodiment, the traveling direction of the electromagnetic signal 720 is perpendicular to the surface of the carbon nanotube structure. A distance between the electromagnetic signal generator and the sound wave generator 714 can be set so that the sound wave generator 714 can receive the electromagnetic signal 720 successfully.

  The modulation device 718 is installed in the transmission path of the electromagnetic signal 720. Further, the modulation device 718 includes a density modulation element (not shown) and / or a frequency modulation element (not shown). The modulator 718 modulates the density and / or frequency of the electromagnetic signal 720 to generate sound waves. In order to control the state of the electromagnetic signal 720, an on / off control circuit can be installed in the modulator 718. In this embodiment, the modulation device 718 directly modulates the density of the electromagnetic signal 720. The modulation device 718 and the electromagnetic signal device are integrated or separated by a predetermined distance. In this embodiment, the modulation device 718 is an electro-optic crystal. When the electromagnetic signal 720 is a fluctuation signal (for example, a pulse laser), the modulation device 718 can be selectively installed.

  In the present embodiment, the density of sound waves generated from the thermoacoustic device 70 is 50 dB SPL. When the input power is 4.5 W, the frequency response range of the thermoacoustic device 70 is 1 Hz to 100 KHz. In this case, the sound wave generated by the thermoacoustic device 70 can reach about 70 dB.

  Referring to FIG. 23, the carbon nanotube film of Example 1 is irradiated using one pulsed femtosecond laser signal. In this case, the wavelength of the femtosecond laser signal is 800 nm. Referring to FIG. 23, after receiving the femtosecond laser signal, the carbon nanotube film generates a sound pressure signal. The width of the sound pressure signal is 10 μm to 20 μm. When the width of the laser signal is 20 μm or more, the width of the sound pressure signal increases as the width of the laser signal increases. When the carbon nanotube film is irradiated with a laser having a width of 100 μm, the carbon nanotube film can generate a sound pressure signal having a width of 100 μm. Referring to FIGS. 24 to 27, the sound pressure signal generated by the carbon nanotube film is measured by irradiating the carbon nanotube structure using lasers having different wavelengths. The lasers used in FIGS. 24 to 27 are ultraviolet light having a wavelength of 355 nm, visible light having a wavelength of 532 nm, infrared light having a wavelength of 1.06 μm, and far infrared light having a wavelength of 10.6 μm. Referring to FIGS. 24 to 27, it can be understood that the sound pressure generated from the carbon nanotube film increases as the output of the laser increases.

(Example 8)
Referring to FIG. 28, the thermoacoustic apparatus 80 of the present embodiment has the following different points from the seventh embodiment. The thermoacoustic device 80 according to the present embodiment includes an electromagnetic signal device 812, a sound wave generator 814, a frame portion 816, and a modulation device 818. The frame portion 816 supports the sound wave generator 814 with two bars. Thereby, a part of the sound wave generator 814 is suspended. The electromagnetic signal device 812 is installed to be separated from the sound wave generator 814 by a predetermined distance, and generates an electromagnetic signal 820.

  The thermoacoustic device 80 further includes a sound collector 822. The sound collector 822 is installed on the opposite side of the sound wave generator 814 from the side facing the electromagnetic signal device 812 so as to be separated from the sound wave generator 814 by a predetermined distance. As a result, a sound collection space is formed between the sound wave generator 814 and the sound collector 822. The sound collector 822 may have a flat surface or a curved surface. The sound quality of the thermoacoustic device 80 can be improved using the sound collection space 824. The distance between the sound collector 822 and the sound wave generator 814 is set to 1 cm to 1 m according to the size of the sound wave generator 814.

Example 9
Referring to FIG. 29, the thermoacoustic device 90 of the present embodiment has the following different points from the eighth embodiment. The thermoacoustic device 90 of this embodiment includes an electromagnetic signal device 912, a sound wave generator 914, a frame portion 916, and a modulation device 918. The electromagnetic signal device 912 is installed to be separated from the sound wave generator 914 by a predetermined distance, and generates an electromagnetic signal 920.

  As long as the sound collection space 924 having the opening 926 can be formed by the frame portion 916 and the sound wave generator 914, the frame portion 916 can be provided in any shape. In the present embodiment, the frame portion 916 has a shape such as an L shape or a U shape (see the support body 56 of the fifth embodiment). The sound wave generator 914 covers the opening 926 of the frame portion 916 and forms a Helmholtz resonator with the frame portion 916. Since the sound wave generated by the sound wave generator 914 is reflected by the side wall of the frame portion 916, the sound quality of the thermoacoustic device 90 can be improved. Of course, the sound collection space 924 is an open space or a sealed space.

(Example 10)
Referring to FIG. 30, the thermoacoustic apparatus 1000 according to the present embodiment has the following different points from the seventh embodiment. The thermoacoustic apparatus 1000 according to the present embodiment includes an electromagnetic signal device 1012, a sound wave generator 1014, a support 1016, and a modulation device 1018. The electromagnetic signal device 1012 further includes an optical fiber 1022. An electromagnetic signal generator 1024 is installed so as to be separated from the sound wave generator 104 by a predetermined distance. The optical signal from the electromagnetic signal generator 1024 is transmitted by the optical fiber 1022. The modulation device 1018 is installed at one end of the optical fiber or between both ends of the optical fiber. In this embodiment, the modulation device 1018 is installed near the sound wave generator 1014 so as to be connected to one end of the optical fiber 1022. Further, an electromagnetic reflection element can be installed to transmit the electromagnetic signal 1020 along a predetermined traveling direction.

(Example 11)
Referring to FIG. 31, the thermoacoustic apparatus 2000 of the present embodiment has the following different points from the seventh embodiment. The thermoacoustic device 2000 according to the present embodiment includes an electromagnetic signal device 2012 and a sound wave generator 2014. The electromagnetic signal device 2012 is installed to be separated from the sound wave generator 2014 at a predetermined distance, and generates an electromagnetic signal 2020. The electromagnetic signal device 2012 generates signals having different densities and / or frequencies. In this embodiment, the electromagnetic signal device 2012 is a pulse laser generator that emits a pulse laser. Of course, the thermoacoustic apparatus 2000 of the present embodiment, which is the same as all the embodiments described above, includes a frame portion and / or a support for supporting the sound wave generator 2014.

(Example 12)
Referring to FIGS. 32 to 33, the thermoacoustic device 3000 according to the present embodiment includes an electromagnetic signal device 3012 and a sound wave generator 3014. The electromagnetic signal device 3012 generates an electromagnetic signal 3020. The electromagnetic signal device 3012 generates signals having different densities and / or frequencies. Further, the thermoacoustic device 3000 includes a modulation circuit 3018. The modulation circuit 3018 is electrically connected to the electromagnetic signal device 3012 and can modulate the density and frequency of the electromagnetic signal transmitted from the electromagnetic signal device 3012 according to the input electric signal.

  By irradiating light having different frequencies and / or densities, the sound wave generator 3014 can generate sound. In this embodiment, the electromagnetic signal device 3012 includes at least one light emitting diode (not shown) that emits visible light. The light emitting diode has a rated voltage of 3.4 V to 3.6 V, a rated current of 360 mA, a rated output of 1.1 W, and a luminous efficiency of 1 m / W. There is no limit to the number of light emitting diodes. As an example, when 16 light emitting diodes are used, a frame 3016 for supporting the sound wave generator 3014 is installed in the thermoacoustic device 3000. The sound wave generator 3014 may contact the surface of the light emitting diode. Alternatively, the electromagnetic signal device 3012 may be installed near the sound wave generator 3014 (a distance of 1 cm).

  Further, the thermoacoustic device 3000 includes an electrical signal device 3040 electrically connected to the modulation circuit 3018. The electric signal device 3040 transmits an electric signal to the modulation circuit 3018. For example, when the electric signal device 3040 is an MP3 player, the thermoacoustic device 3000 can reproduce the sound of the MP3 player.

(Example 13)
Referring to FIG. 34, a sound transmission system 4000 is provided in the present embodiment. The sound transmission system 4000 includes a sound-electric conversion device 4040, an electric-wave conversion device 4030, a sound wave generator 4014, and a support 4016. The sound-electric conversion device 4040 is electrically connected to the electric-wave conversion device 4030. The electromagnetic wave conversion device 4030 is installed at a predetermined distance from the sound wave generator 4014.

  The sound-electric conversion device 4040 can convert sound pressure into an electric signal and output the electric signal to the electric-wave conversion device 4030. The electromagnetic wave conversion device 4030 transmits an electromagnetic signal by the electric signal output from the sound electric conversion device 4040. The sound wave generator 4014 includes a carbon nanotube structure. After the electromagnetic signal is transmitted to the carbon nanotube structure, the electromagnetic signal can be converted into heat by the carbon nanotube structure. When the heat is transmitted to a surrounding medium in contact with the carbon nanotube structure, a thermoacoustic effect is generated. The sound-electric conversion device 4040 is a microphone or a pressure sensor. In this embodiment, the sound-electric conversion device 4040 is a microphone.

  Further, the electromagnetic wave conversion device 4030 includes an electromagnetic signal device 4012 and a modulation device 4018. The electromagnetic signal device 4012 and the modulation device 4018 are separated or integrated at a predetermined distance. The electromagnetic signal device 4012 generates an electromagnetic signal 4020. The modulator 4018 is connected to the sound-electrical converter 4040 and can modulate the density or / and frequency of the electromagnetic signal 4020 transmitted from the electromagnetic signal device 4012.

  The electromagnetic signal device 4012, the sound wave generator 4014, and the support body 4016 are similar to the electromagnetic signal device, the sound wave generator, and the support body (or frame portion) in the above-described embodiments, respectively. The sound transmission system 4000 further includes an optical fiber (not shown). The optical fiber is connected to the electromagnetic wave conversion device 4030 and transmits the electromagnetic signal 4020 to the carbon nanotube structure. In this embodiment, the electromagnetic signal device 4012 is a laser device including a pump source and a resonator.

  In one of the embodiments described above, the thermoacoustic device can utilize a plurality of different input devices. For example, in one embodiment, the thermoacoustic device may include an electric input device and an electromagnetic input device at the same time.

  Referring to FIG. 35, a method of generating sound waves according to the present invention includes a first step of providing a carbon nanotube structure, and transferring a signal to the carbon nanotube structure to generate heat in the carbon nanotube structure. Two steps, a third step in which heat is radiated to the surrounding medium in contact with the carbon nanotube structure, and a fourth step in which a thermoacoustic effect occurs.

  In the first step, the carbon nanotube structure is the same as the carbon nanotube structure used in the thermoacoustic device 10. In the second step, the signal is transferred to the signal device by at least two electrodes. In the third and fourth steps, the heat generated in the carbon nanotube structure heats the surrounding medium. Sound waves can be generated by repeatedly heating the surrounding medium. The above is the thermoacoustic effect.

DESCRIPTION OF SYMBOLS 10 Thermoacoustic apparatus 100 Speaker 102 Voice coil 104 Magnet 106 Cone 12 Signal apparatus 14 Sound wave generator 142 1st electrode 143a Carbon nanotube film 143b Carbon nanotube segment 144 Second electrode 145 Carbon nanotube 146 Carbon nanotube wire 149 Conductive wire 20 Thermoacoustic apparatus 22 signal device 24 sound wave generator 242 first electrode 244 second electrode 246 third electrode 248 fourth electrode 249 first conductive wire 249 ′ second conductive wire 30 thermoacoustic device 32 signal device 34 sound wave generator 342 first electrode 344 Second electrode 349 Conductive wire 36 Support body 40 Thermoacoustic device 42 Signal device 44 Sound wave generator 442 First electrode 444 Second electrode 446 Third electrode 448 Fourth electrode 449 Conductive wire 50 Thermoacoustic device 52 signal device 54 sound wave generator 542 first electrode 544 second electrode 549 conductive wire 56 support 562 first end 564 second end 60 thermoacoustic device 62 signal device 64 sound wave generator 66 power amplifier 662 input unit 664 output unit 69 Frequency reduction circuit 70 Thermoacoustic device 712 Electromagnetic signal device 714 Sound wave generator 716 Support body 718 Modulator device 720 Electromagnetic signal 722 Frame portion 80 Thermoacoustic device 812 Electromagnetic signal device 814 Sound wave generator 816 Frame portion 818 Modulator device 820 Electromagnetic signal 822 Collection Sound generator 824 Sound collection space 90 Thermoacoustic device 912 Electromagnetic signal device 914 Sound wave generator 916 Frame portion 918 Modulation device 920 Electromagnetic signal 924 Sound collection space 926 Opening 1000 Thermoacoustic device 1012 Electromagnetic signal device 1014 Sound wave generator 1016 Support 1018 Control device 1022 Optical fiber 1024 Electromagnetic signal generator 1020 Electromagnetic signal 2000 Thermoacoustic device 2012 Electromagnetic signal device 2014 Sound wave generator 2020 Electromagnetic signal 3000 Thermoacoustic device 3012 Electromagnetic signal device 3014 Sound wave generator 3018 Modulation circuit 3020 Electromagnetic signal 3040 Electric signal device 4000 Sound transmission system 4012 Electromagnetic signal device 4014 Sound wave generator 4016 Support 4018 Modulator 4030 Electric wave converter 4040 Sound electric converter

Claims (10)

An electromagnetic wave generator , and a sound wave generator including a carbon nanotube structure disposed at a predetermined distance from the electromagnetic wave generator ,
The electromagnetic wave generator is configured to transmit an electromagnetic wave to the carbon nanotube structure,
The carbon nanotube structure comprises at least one carbon nanotube film;
The thermoacoustic apparatus, wherein the single carbon nanotube film includes a plurality of carbon nanotubes arranged in parallel to each other. An electromagnetic wave generator , and a sound wave generator including a carbon nanotube structure disposed at a predetermined distance from the electromagnetic wave generator ,
The electromagnetic wave generator is configured to transmit an electromagnetic wave to the carbon nanotube structure,
The carbon nanotube structure converts the electromagnetic wave into heat to produce a thermoacoustic effect in the medium, the carbon nanotube structure includes at least one carbon nanotube film;
The thermoacoustic apparatus, wherein the single carbon nanotube film includes a plurality of carbon nanotubes arranged in parallel to each other. The carbon nanotube structure is a thin film shape, wherein the heat capacity per unit area 0 is (0 NOT ^{INCLUDED) ~2 × 10 -4 J / cm} 2 · K, to claim 1 or 2 The thermoacoustic apparatus as described.   The apparatus according to claim 1 or 2, wherein in the single carbon nanotube film, the length of the single carbon nanotube is 1 cm to 30 cm.   The thermoacoustic device according to any one of claims 1 to 4, wherein in the single carbon nanotube film, the plurality of carbon nanotubes have the same length.   The thermoacoustic device according to any one of claims 1 to 5, wherein in the single carbon nanotube film, the plurality of carbon nanotubes are arranged in parallel along the same direction. .   The thermoacoustic device according to any one of claims 1 to 6, wherein a length of each carbon nanotube in the carbon nanotube film is the same as a length of the carbon nanotube film. The thermoacoustic apparatus according to any one of claims 1 to 7, wherein the electromagnetic wave generator includes an optical fiber. The heat according to any one of claims 1 to 8, wherein a modulator for modulating the density and / or frequency of the electromagnetic wave is installed between the electromagnetic wave generator and the sound wave generator. Acoustic device.   The thermoacoustic device according to any one of claims 1 to 9, wherein a support for supporting the sound wave generator is installed in the sound wave generator.