JP2009302057A - Planar heat source, and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a planar heat source high in efficiency in converting electric energy to thermal energy. <P>SOLUTION: This planar heat source includes a heating element, and at least two electrodes electrically connected to the heating element. The heating element includes a carbon nanotube structure, which includes a plurality of carbon nanotubes. The carbon nanotube structure is characterized in that the plurality of carbon nanotubes are connected to one another by intermolecular force, and uniformly distributed. The carbon nanotube structure is also characterized in that the carbon nanotubes are oriented and arranged. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a surface heat source and a method for producing the same, and more particularly to a surface heat source using carbon nanotubes and a method for producing the same.

  Heat sources play an important role in areas such as people's life and scientific research. For example, it is applied to an electric heater, an electric heater, an infrared therapy device, and the like. The surface heat source is a kind of heat source and is a two-dimensional structure. The surface heat source can simultaneously heat each part of the object to be heated, has a large heating area, good heating uniformity, and high efficiency.

  As a conventional technique, a surface heat source includes a heating element and at least two electrodes. The at least two electrodes are disposed on the surface of the heating element and are electrically connected to the heating element. When a current is passed through the heating element by the at least two electrodes, heat is released from the heating element. A conventional surface heat source uses a metal filament as a heating element to convert electric energy into heat energy.

S. Iijima, “Helical Microtubules of Graphic Carbon”, Nature, 1991, vol. 354, p. 56 “New challenge in thin film researcher research”, Journal of Non-Crystalline Solids, 2002, 299-302, pp. 1304-1310.

  However, the metal filament has low strength and is easily broken. In particular, when the metal filament is bent at a predetermined angle, there is a drawback that the metal filament is more easily broken. In addition, since the heat emitted from the metal filament is radiated to the outside at a standard wavelength, there is a disadvantage in that the efficiency of converting electric energy into heat energy is low and energy is wasted.

  Therefore, an object of the present invention is to provide a surface heat source with high efficiency for converting electric energy into heat energy.

  The surface heat source includes a heating element and at least two electrodes electrically connected to the heating element. The heating element includes a carbon nanotube structure, and the carbon nanotube structure includes a plurality of carbon nanotubes.

  In the carbon nanotube structure, a plurality of carbon nanotubes are connected by an intermolecular force and are uniformly distributed.

  In the carbon nanotube structure, the carbon nanotubes are aligned and arranged.

  In the carbon nanotube structure, the carbon nanotubes are arranged without being oriented.

  The carbon nanotube structure includes at least one carbon nanotube film, at least one carbon nanotube linear structure, or a composite structure of a carbon nanotube film and a carbon nanotube linear structure.

  The carbon nanotube structure includes at least two laminated carbon nanotube films, and an angle between the carbon nanotubes between adjacent carbon nanotube films is 0 ° to 90 °.

  The heating element is installed on the substrate.

  A reflective layer is included, and the reflective layer is disposed on the surface of the substrate, and is used to reflect the heat released from the heating element.

Compared to a conventional surface heat source, in the surface heat source of the present invention, the heating element includes a carbon nanotube structure, and the carbon nanotube structure includes a plurality of carbon nanotubes. Since the plurality of carbon nanotubes are uniformly arranged and the heating element has a uniform thickness and resistance, the heating element can uniformly dissipate heat and convert electrical energy into thermal energy. The efficiency is high, and the heat capacity of the unit area of the carbon nanotube structure is 2 × 10 ⁻⁴ J / m ² K or less. Therefore, the surface heat source has a fast temperature rising rate, a fast thermal response speed, and a fast heat exchange rate.

  Since the carbon nanotube in the heating element has excellent mechanical performance, excellent toughness and excellent mechanical strength, the heating element has excellent mechanical performance, excellent toughness and mechanical strength, and has a long service life. . Furthermore, a flexible surface heat source can be manufactured using the heating element.

  Since the diameter of the carbon nanotube in the heating element is small, the heating element has a small thickness. Therefore, it is possible to manufacture a very small surface heat source, and it is possible to heat a small element to be heated using the small surface heat source.

It is a SEM photograph of the carbon nanotube film which consists of a carbon nanotube with which the end was connected in the surface heat source concerning the example of the present invention. It is a figure which shows the structure of a carbon nanotube segment. 4 is an SEM photograph of a carbon nanotube film in which carbon nanotubes are arranged isotropically in a surface heat source according to an example of the present invention. It is a SEM photograph of the carbon nanotube film in which the carbon nanotube was arranged along the same direction in the surface heat source concerning the example of the present invention. It is a photograph of the carbon nanotube film of fluff structure in the surface heat source concerning the example of the present invention. It is a SEM photograph of the carbon nanotube film of a fluff structure in the surface heat source concerning the example of the present invention. It is the photograph of the carbon nanotube structure of the filtered fluff structure. It is a SEM photograph of the non-twisted carbon nanotube linear structure in the surface heat source which concerns on the Example of this invention. It is a SEM photograph of the twisted carbon nanotube linear structure in the surface heat source which concerns on the Example of this invention. It is a SEM photograph of the non-twisted carbon nanotube concerning the example of the present invention. It is a SEM photograph of the carbon nanotube of the twisted wire structure concerning the example of the present invention. It is a figure which shows the structure of the surface heat source which concerns on Example 1 of this invention. It is sectional drawing which cuts the surface heat source which concerns on Example 1 of this invention along the XIII-XIII line | wire shown in FIG. It is a figure which shows the structure of the surface heat source which concerns on Example 2 of this invention. It is a figure which shows the structure of the surface heat source which concerns on Example 3 of this invention. It is a figure which shows the structure of the surface heat source which concerns on Example 4 of this invention. It is a figure which shows the structure of the surface heat source which concerns on Example 5 of this invention. It is the graph which measured the surface temperature of the carbon nanotube structure in the present Example 1 using a different surveying instrument at different work rates.

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

Example 1
Referring to FIGS. 12 and 13, the first embodiment of the present invention provides a surface heat source 10. The surface heat source 10 is a two-dimensional structure, that is, a structure extending along a two-dimensional direction. The surface heat source 10 includes a substrate 18, a reflective layer 17, a heating element 16, a protective layer 15, a first electrode 12, and a second electrode 14.

  The reflective layer 17 is disposed on one surface of the substrate 18. The heating element 16 is installed on the opposite surface of the reflective layer 17 to the surface in contact with the substrate 18. The first electrode 12 and the second electrode 14 are electrically connected to the heating element 16. In the present embodiment, the first electrode 12 and the second electrode 14 are disposed on the surface of the heating element 16 at an interval so as to be electrically connected to the heating element 16. A current is passed through the heating element 16 by the first electrode 12 and the second electrode 14. The protective layer 15 is disposed on the surface of the heating element 16 opposite to the surface in contact with the reflective layer. The protective layer 15 covers the first electrode 12 and the second electrode 14 and can prevent dust from adhering to the heating element 16.

  The shape and dimensions of the substrate 18 can be selected according to the actual application. For example, the substrate 18 is square, circular or triangular. The substrate 18 has a flat or curved surface. It is used to support the heating element 16 and the reflective layer 17. The material of the substrate 18 may be, for example, a hard material such as ceramics, glass, resin, quartz, or may be a soft material such as plastic and soft fiber. In this embodiment, the substrate 18 is a ceramic substrate having a thickness of 1 millimeter. When the heating element 16 has a self-supporting structure, the substrate 18 in the surface heat source 10 may not be used.

  The reflective layer 17 is used to reflect the heat emitted from the heating element 16 and release the heat along one direction to increase the heating efficiency. The material of the reflective layer 17 is an insulating material such as a metal oxide, a metal salt, and ceramics. In the present embodiment, the reflective layer 17 is an aluminum oxide film and has a thickness of 100 micrometers to 0.5 millimeters. In the present embodiment, the thickness of the reflective layer 17 is 0.1 millicm. Of course, the reflective layer 17 may be disposed on the surface of the substrate 18 away from the heating element 16. That is, the substrate 18 is disposed between the heating element 16 and the reflective layer 17, and reflects heat better by the reflective layer 17. The reflective layer 17 may not be installed, that is, the heating element 16 may be installed directly on the surface of the substrate 18. Accordingly, the heating direction of the surface heat source 10 is not limited, and the surface heat source 10 can release heat from two surfaces.

  The heating element 16 includes a carbon nanotube structure. The carbon nanotube structure is a self-supporting structure. The self-supporting structure means that the carbon nanotube structure is used independently without using a support. The carbon nanotube structure includes a plurality of carbon nanotubes, and the plurality of carbon nanotubes are connected by an intermolecular force and are uniformly distributed. 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 thermal response speed of the carbon nanotube structure is related to the thickness of the carbon nanotube structure. When the carbon nanotube structures have the same surface area, the thermal response speed is slow if the thickness is large, and the thermal response speed is fast if the thickness is thin. The purity of the carbon nanotube structure is high, and the carbon nanotube structure has a large specific surface area (for example, 100 m ² / g or more). The carbon nanotube structure has a heat capacity per unit area of 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. When the heat capacity of the carbon nanotube structure is very low, the heating element 16 can be quickly heated. Since the density of the carbon nanotube structure is low and reaches about 1.35 g / cm ³ , the light transmittance of the carbon nanotube structure is high.

  (1) 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 Superaligned array of carbon nanotubes, Non-Patent Document 2). In the single carbon nanotube film 143a, the ends of the plurality of carbon nanotubes are connected along the same direction. That is, the single carbon nanotube film 143a includes a plurality of carbon nanotubes whose end portions in the length direction are connected to each other by intermolecular force. Referring to FIG. 2, 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. The carbon nanotube film 143a has a width of 100 μm to 10 cm and a thickness of 0.5 nm to 100 μm. When the thickness of the carbon nanotube film 143a is 10 μm or less, the transmissivity of the carbon nanotube film 143a reaches about 90% or more, so that it can be used as a transparent heat source.

  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.

  The method for manufacturing the carbon nanotube film includes the following steps.

  In the first step, a carbon nanotube array is provided. The carbon nanotube array is a super aligned carbon nanotube array (see Superaligned array of carbon nanotubes, Non-Patent Document 2), and the method for 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, and the substrate 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 this embodiment, it is preferable 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 two or more alloys thereof. In step (c), the substrate on which the catalyst layer has been formed 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 reaction furnace, heated with a protective gas at a temperature of 500 ° C. to 740 ° C., and then a carbon-containing gas is introduced to react for 5 to 30 minutes. Thus, a super-aligned carbon nanotube array (Non-patent Document 2) can be grown. The carbon nanotube array has a height of 100 micrometers or more. The carbon nanotube array is composed of a plurality of carbon nanotubes that grow parallel to each other and perpendicular to the substrate. Since the carbon nanotubes are long, the carbon nanotubes are partially entangled with each other. By controlling the growth conditions, the carbon nanotube array does not contain impurities such as amorphous carbon and remaining metal particles as a catalyst.

  In this embodiment, as the gas containing carbon, for example, active hydrocarbons such as acetylene, ethylene, and methane are selected, and it is preferable to select ethylene. The protective gas is nitrogen gas or inert gas, preferably argon gas.

  The carbon nanotube array provided from this example is not limited to being manufactured by the above-described manufacturing method, and may be manufactured by an arc discharge method or a laser evaporation method.

  In the second step, at least one carbon nanotube film is stretched from the carbon nanotube array. First, using a tool such as tweezers, a plurality of carbon nanotube ends are provided. For example, a plurality of carbon nanotube ends are used by using a tape having a certain width. Next, the plurality of carbon nanotubes are pulled out at a predetermined speed to form a continuous carbon nanotube film composed of a plurality of carbon nanotube bundles.

  In the step of drawing out the plurality of carbon nanotubes, when the plurality of carbon nanotubes are detached from the base material, the carbon nanotube bundles are joined to each other by an intermolecular force to form a continuous carbon nanotube film. .

  (2) The carbon nanotube structure includes at least one carbon nanotube film. 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.

  (3) The carbon nanotube structure includes at least one carbon nanotube film. The carbon nanotube film is shown in FIG. 3 or FIG. The plurality of carbon nanotubes in the single carbon nanotube film are arranged isotropically, arranged along a predetermined direction, or arranged along a plurality of different directions. The carbon nanotube film has a sheet-like self-supporting structure formed by pressing the carbon nanotube array by applying a predetermined pressure by using a pushing tool and depressing the carbon nanotube array with the pressure. is there. The arrangement direction of the carbon nanotubes in the carbon nanotube film is determined by the shape of the pushing device and the pushing direction of the carbon nanotube array.

  Referring to FIG. 3, the carbon nanotubes in a single carbon nanotube film are arranged without being oriented. The carbon nanotube film includes a plurality of carbon nanotubes arranged isotropically. Adjacent carbon nanotubes attract each other by intermolecular force and connect. 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 pressing device having a flat surface.

  Referring to FIG. 4, carbon nanotubes in a single carbon nanotube film are aligned and arranged. The carbon nanotube film includes a plurality of carbon nanotubes arranged along the same direction. When the carbon nanotube array is simultaneously pressed along the same direction using a pressing device having a roller shape, a carbon nanotube film including carbon nanotubes arranged in the same direction is formed. In addition, when the carbon nanotube array is simultaneously pressed along different directions using a pressing device having a roller shape, a carbon nanotube film including carbon nanotubes arranged in a selective direction along the different directions Is formed.

  The degree of inclination 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 not less than 0 ° and not more than 15 °. Preferably, the 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 tilt. The thickness of the carbon nanotube film is related to the height of the carbon nanotube array and the pressure applied to the carbon nanotube array. That is, as the height of the carbon nanotube array increases and the pressure applied to the carbon nanotube array decreases, the thickness of the carbon nanotube film increases. On the contrary, as the height of the carbon nanotube array becomes smaller and as the pressure applied to the carbon nanotube array becomes larger, the thickness of the carbon nanotube film becomes smaller.

  (4) The carbon nanotube structure includes at least one carbon nanotube film. 5 and 6, 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 said carbon nanotube is 100 nm or more, and it is preferable in it being 100 nm-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 method for producing the carbon nanotube film includes the following steps.

  In the first step, a carbon nanotube raw material is provided.

  The carbon nanotubes are peeled off from the substrate with a tool such as a knife to form a carbon nanotube raw material. The carbon nanotubes are intertwined with each other to some extent. In the carbon nanotube raw material, the carbon nanotube has a length of 100 micrometers or more, preferably 10 micrometers or more.

  In the second step, the carbon nanotube raw material is immersed in a solvent, and the carbon nanotube raw material is treated to form a fluffy carbon nanotube structure.

  After the carbon nanotube raw material is immersed in the solvent, the carbon nanotube is formed into a fluff structure by a method such as ultrasonic dispersion, high intensity stirring or vibration. The solvent is water or a volatile organic solvent. Treatment is performed for 10 to 30 minutes with respect to the solvent containing carbon nanotubes by an ultrasonic dispersion method. Since the carbon nanotube has a large specific surface area and a large intermolecular force is generated between the carbon nanotubes, the carbon nanotubes are entangled and formed into a fluff structure.

  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.

  First, provide a funnel with filter paper. When the solvent containing the fluffy carbon nanotube structure is applied to the funnel on which the filter paper is placed and then left standing for a while to dry, the fluffy carbon nanotube structure is separated. Referring to FIG. 7, the carbon nanotubes in the carbon nanotube structure having the fluff structure are entangled with each other to form an irregular fluff structure.

  The separated fluff structure carbon nanotube structure is placed in a container, the fluff structure carbon nanotube structure is expanded into a predetermined shape, and a predetermined pressure is applied to the expanded fluff structure carbon nanotube structure, When the solvent remaining in the fluffy carbon nanotube structure is roasted or the solvent is naturally evaporated, the fluffy carbon nanotube film shown in FIGS. 5 and 6 is formed.

  The thickness and surface density of the fluffy carbon nanotube film can be controlled by the area where the fluffy carbon nanotube structure is developed. That is, the fluff-structured carbon nanotube structure having a certain volume has a smaller thickness and areal density of the fluff-structured carbon nanotube film as the developed area increases.

  In addition, a carbon nanotube film having a fluff structure is formed using a microporous film and an air pump funnel. Specifically, a microporous membrane and an air pump funnel are provided, and the solvent containing the fluff-structured carbon nanotube structure is passed through the microporous membrane to the air pump funnel, and then extracted to the air pump funnel and dried. As a result, a carbon nanotube film having a fluff structure is formed. The microporous film 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 air pressure is applied to the fluffy carbon nanotube film by using the air pump, a uniform fluffy carbon nanotube film can be formed.

  When the carbon nanotube structure includes only one 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 a plurality of stacked carbon nanotube films, an angle α formed by the carbon nanotubes between adjacent carbon nanotube films is 0 ° to 90 °. Both ends of the carbon nanotubes in the at least one carbon nanotube film are electrically connected to the first electrode and the second electrode, respectively.

  (5) The carbon nanotube structure includes one carbon nanotube film segment. All the carbon nanotubes in the segments of the carbon nanotube film are parallel to each other and arranged in parallel along 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 first electrode 12 and the second electrode 14 are made of a conductive material, and are disposed on the same surface of the heating element 16 or both opposing surfaces of the heating element 16. The shape 14 of the first electrode 12 and the second electrode is not limited. The first electrode 12 and the second electrode 14 are conductive films when applied to a very small surface heat source, and the thickness of the conductive film is 0.5 nanometer to 100 micrometers. The material of the conductive film is a metal, an alloy, an indium tin oxide (ITO) film, antimony tin oxide (ATO), a silver paste, a conductive polymer, or a carbon nanotube structure. The metal is aluminum, copper, tungsten, molybdenum, gold, titanium, neodymium, palladium, cesium, or the like. The alloy is an alloy of the metal. The carbon nanotube structure includes any one or various carbon nanotube films described above.

  Since the carbon nanotube structure in the heating element 16 has adhesiveness, the first electrode 12 and the second electrode 14 can be directly installed on the surface of the heating element 16. Alternatively, the first electrode 12 and the second electrode 14 may be bonded to the surface of the heating element 16 with a conductive adhesive. The first electrode 12 and the second electrode 14 are electrically connected to the heating element 16 and at the same time are well fixed to the surface of the heating element 16. The conductive adhesive is a silver paste.

  In this embodiment, the heating element 16 is a stack of hundred carbon nanotube films. Adjacent carbon nanotube films are closely connected by intermolecular forces. Referring to FIG. 2, each carbon nanotube film includes carbon nanotubes connected end to end and arranged along the same direction. In the heating element 16, the arrangement direction of the carbon nanotubes in the adjacent carbon nanotube film is vertical. Some of the carbon nanotubes are arranged in the direction from the first electrode 12 to the second electrode 14. The heating element 16 has an area of 9 square centimeters, a length of 3 centimeters, a width of 3 centimeters, and a thickness of 500 nanometers. The first electrode 12 and the second electrode 14 are stacked carbon nanotube films as shown in FIG. 1, and the carbon nanotubes in adjacent carbon nanotube films can be arranged along the same direction.

  The material of the protective layer 15 is, for example, an insulating material such as plastic, rubber and resin, or a conductive material such as metal or alloy. The thickness of the protective layer 15 is not limited and can be selected according to the actual application. The protective layer 15 is covered with the first electrode 12, the second electrode 14, and the heating element 16, allows the surface heat source 10 to be used in an insulated state, and prevents dust from adhering to the heating element 16. . Of course, the protective layer 15 may not be provided. In the present embodiment, the protective layer 15 is made of rubber and has a thickness of 0.5 millimeters to 2 millimeters, and is used to protect the heating element 26.

  When the first electrode 12 and the second electrode 14 of the surface heat source 10 are electrically connected to a power source (not shown) and a voltage is applied to the heating element 16 by the first electrode 12 and the second electrode 14, The carbon nanotube structure of the heating element 16 in the surface heat source 10 can emit an electromagnetic wave having a predetermined wavelength. The heating target may be placed in direct contact with the surface heat source 10 or at a predetermined distance from the surface heat source 10. The electromagnetic wave emitted from the carbon nanotube structure heats the heating target. By controlling the dimensions of the heating element 16 and the voltage applied to the heating element 16, the heat released from the heating element 16 can be controlled. When the voltage is constant, the wavelength of the electromagnetic wave emitted from the heating element 16 can be adjusted by changing the thickness of the heating element 16. That is, the thicker the heating element 16, the shorter the wavelength of the electromagnetic wave emitted from the heating element 16. When the thickness of the heating element 16 is constant, the wavelength of the electromagnetic wave emitted from the heating element 16 becomes shorter as the voltage applied to the heating element 16 increases. Therefore, the surface heat source 10 can be easily controlled.

  When the surface heat source 10 of this embodiment is placed in an air atmosphere and a voltage of 10 V to 30 V is applied to the heating element 16 by the first electrode 12 and the second electrode 14, the temperature of the surface heat source 10 is 50 ° C. to 50 ° C. Raise to 500 ° C. When the temperature of the carbon nanotube structure is increased to 200 ° C. to 450 ° C., the heating element 16 releases heat. The heating element 16 is excellent in that the heat radiation is stable, the efficiency of heat release is high, and the amount of heat released is large.

  FIG. 18 is a graph obtained by measuring the surface temperature of the carbon nanotube structure in the present example using two different surveying instruments at different powers. The two surveying instruments are the infrared thermometer RAYTEK RAYNER IP-M and the infrared thermometer AZ-8859, respectively. Surveying shows that the surface temperature of the carbon nanotube structure can reach 370 ° C. when the heating power is 36 watts. The carbon nanotube structure has high efficiency in converting electric energy into heat energy.

  When the surface heat source 10 of this embodiment is placed in a vacuum apparatus and a voltage of 80 V to 150 V is applied to the heating element 16 by the first electrode 12 and the second electrode 14, the surface heat source 10 is an electromagnetic wave having a short wavelength. Can be released. The surface heat source 10 emits visible light such as red light and yellow light, for example, and can form normal heat radiation. In this case, the temperature of the surface heat source 10 can reach about 1500 ° C. When the voltage applied to the surface heat source 10 is sufficiently strong, the surface heat source 10 can emit ultraviolet light.

  The surface heat source 10 may include a plurality of first electrodes 12 and a plurality of second electrodes 14. The plurality of first electrodes 12 and the plurality of second electrodes 14 are disposed at intervals, and are electrically connected to the heating element 16, respectively.

  When the first electrode 12 and the second electrode 14 of the surface heat source 10 are electrically connected to a power source, the carbon nanotube structure of the heating element 16 in the surface heat source 10 may emit an electromagnetic wave having a predetermined wavelength. it can. An object to be heated may be in direct contact with the surface heat source 10 or an object to be heated may be installed at a predetermined distance from the surface heat source 10. The electromagnetic wave emitted from the carbon nanotube structure heats the heating target.

(Example 2)
Referring to FIG. 14, the present embodiment provides a surface heat source 20. The surface heat source 20 of this embodiment includes a substrate 28, a reflective layer 27, a heating element 26, a protective layer 25, a first electrode 22 and a second electrode 24. The reflective layer 27 is disposed on one surface of the substrate 28. The heating element 26 is disposed on the surface of the reflective layer 27 opposite to the surface in contact with the substrate 28. The first electrode 22 and the second electrode 24 are electrically connected to the heating element 26. Referring to FIGS. 9 and 11, the difference between the present embodiment and the first embodiment is that the heating element 26 includes a carbon nanotube structure including a plurality of carbon nanotube linear structures.

The carbon nanotube structure includes at least one carbon nanotube linear structure. The carbon nanotube linear 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, preferably 0 (not including 0) to 5 × 10 ⁻⁵ J / cm ² · K. . The diameter of one carbon nanotube wire is 4.5 nm to 1 cm, and preferably 1 μm to 1 cm. When the carbon nanotube linear structure includes two or more carbon nanotube wires, the carbon nanotube wires are arranged in parallel to form a non-twisted carbon nanotube linear structure (as shown in FIG. 8) or Each carbon nanotube wire is spirally arranged to form a twisted carbon nanotube linear structure (as shown in FIG. 9). That is, referring to FIG. 8, the carbon nanotube wires 161 in the non-twisted carbon nanotube linear structure 160 are arranged along the longitudinal direction of the carbon nanotube linear structure 160. Referring to FIG. 9, the carbon nanotube wires 171 in the twisted carbon nanotube linear structure 170 are spirally arranged along the axial direction of the linear structure 170.

  The carbon nanotube wire 161 in the non-twisted carbon nanotube linear structure 160 and the carbon nanotube wire 171 in the twisted carbon nanotube linear structure 170 are respectively non-twisted carbon nanotube wires (as shown in FIG. 10). ) Or twisted carbon nanotube wire (as shown in FIG. 11).

  The diameter of the carbon nanotube linear structure is 20 micrometers to 2 millimeters, and the size of the diameter is related to the number of the carbon nanotube wires and the diameter thereof. The larger the carbon nanotube wire diameter and the larger the number, the larger the diameter of the carbon nanotube linear structure. On the contrary, the smaller the carbon nanotube wire diameter and the smaller the number, the smaller the diameter of the carbon nanotube linear structure.

  Referring to FIG. 10, the non-twisted carbon nanotube wire is obtained by treating a carbon nanotube film drawn from a carbon nanotube array with an organic solvent. The non-twisted carbon nanotube wire includes a plurality of carbon nanotubes arranged along the longitudinal direction and connected end to end. 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 non-twisted carbon nanotube wire is 0.5 nm to 100 μm. Referring to FIG. 11, the non-twisted 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 0.5 nm to 100 μm.

  Since the carbon nanotubes in the carbon nanotube wire are oriented and arranged, the carbon nanotubes in the carbon nanotube linear structure made of the carbon nanotube wire are oriented and arranged.

  Further, the twisted carbon nanotube wire may be treated with a volatile organic solvent. Adjacent carbon nanotubes in the twisted carbon nanotube wire are tightly connected by intermolecular force due to the action of the surface force of the volatile organic solvent, so that the twisted carbon nanotube wire has a small diameter and specific surface area. It has a large density, excellent mechanical strength and excellent toughness.

  When the carbon nanotube structure includes one carbon nanotube linear structure, both ends of the carbon nanotube in the carbon nanotube linear structure are electrically connected to the first electrode 22 and the second electrode 24, respectively. Is done. When the carbon nanotube structure includes a plurality of carbon nanotube linear structures, the plurality of carbon nanotube linear structures are arranged in parallel or crossed. The distance between the adjacent carbon nanotube linear structures arranged in parallel is 0 to 30 micrometers. The crossing angle of the crossed carbon nanotube linear structure is not limited. The method of installing each of the carbon nanotube linear structures is not limited, and it may be ensured that a uniform heating element 16 can be formed.

  In this embodiment, the heating element 26 includes a plurality of twisted carbon nanotube linear structures 170, and each twisted carbon nanotube linear structure 170 is arranged in parallel to the substrate 28, thereby providing a two-dimensional heating element. Is to form. The twisted carbon nanotube linear structure 170 includes a plurality of twisted carbon nanotube wires 171 arranged in a spiral shape along the axial direction of the linear structure 170. The twisted carbon nanotube wire 171 includes a plurality of carbon nanotubes arranged in a spiral shape along the axial direction of the carbon nanotube wire 171.

  The first electrode 22 and the second electrode 24 may include the carbon nanotube linear structure. In the present embodiment, the first electrode 22 and the second electrode 24 include one carbon nanotube linear structure 160. The carbon nanotube linear structure 160 includes a plurality of non-twisted carbon nanotube wires 161 arranged in parallel along the longitudinal direction of the linear structure 160. The non-twisted carbon nanotube wire 161 includes a plurality of carbon nanotubes arranged along the longitudinal direction and connected end to end.

  Of course, the first electrode 12 and the second electrode 14 of Example 1 may include the carbon nanotube linear structure.

(Example 3)
Referring to FIG. 15, the third embodiment of the present invention provides a surface heat source 30. The surface heat source 30 includes a substrate 38, a heating element 36, a first electrode 32, and a second electrode 34. The heating element 36 is installed on the surface of the substrate 38. The first electrode 32 and the second electrode 34 are electrically connected to the heating element 36. The heating element 36 includes a plurality of carbon nanotube wires. Some of the plurality of carbon nanotube wires are arranged in parallel, and are electrically connected to the first electrode 32 and the second electrode 34. The plurality of carbon nanotube wires are arranged so as to cross each other. For example, another part of the plurality of carbon nanotube wires is vertically arranged on the carbon nanotube wires electrically connected to the first electrode 32 and the second electrode 34. The carbon nanotube wire is a non-twisted carbon nanotube wire (as shown in FIG. 10) or a twisted carbon nanotube wire (as shown in FIG. 11). The first electrode 32 and the second electrode 34 are metal palladium films.

(Example 4)
Referring to FIG. 16, the fourth embodiment of the present invention provides a surface heat source 40. The surface heat source 40 includes a substrate 48, a heating element 46, a first electrode 42 and a second electrode 44. The heating element 46 includes a plurality of carbon nanotube wires. Each carbon nanotube wire is knitted together to form a two-dimensional heating element. The carbon nanotube wire is a non-twisted carbon nanotube wire (as shown in FIG. 10) or a twisted carbon nanotube wire (as shown in FIG. 11). The first electrode 42 and the second electrode 44 are metal palladium films.

(Example 5)
Referring to FIG. 17, the fifth embodiment of the present invention provides a surface heat source 50. The surface heat source 50 and the structure of the surface heat source 30 in the third embodiment are basically the same, and the surface heat source 50 includes a substrate 58, a heating element 56, a first electrode 52, and a second electrode 54. In this embodiment, the heating element 56 includes a single carbon nanotube wire. The carbon nanotube wire is formed into a bent two-dimensional heating element. The carbon nanotube wire is a non-twisted carbon nanotube wire (as shown in FIG. 10) or a twisted carbon nanotube wire (as shown in FIG. 11). The first electrode 52 and the second electrode 54 are metallic palladium films.

In the surface heat source, the heating element includes a carbon nanotube structure, the carbon nanotubes in the carbon nanotube structure are uniformly arranged, and the heating element has a uniform thickness and resistance. Heat can be released, and the efficiency of converting electric energy into heat energy is high, and the heat capacity of the unit area of the carbon nanotube structure is 2 × 10 ⁻⁴ J / m ² K or less. Therefore, the surface heat source has a fast temperature rising rate, a fast thermal response speed, and a fast heat exchange rate.

  Since the carbon nanotube in the heating element has excellent mechanical performance, excellent toughness and excellent mechanical strength, the heating element has excellent mechanical performance, excellent toughness and mechanical strength, and has a long service life. . Furthermore, a flexible surface heat source can be manufactured using the heating element.

  Since the diameter of the carbon nanotube in the heating element is small, the heating element has a small thickness. Therefore, it is possible to manufacture a very small surface heat source, and it is possible to heat a small element to be heated using the small surface heat source.

  An embodiment of the present invention provides a method for manufacturing the surface heat source. Specifically, the following steps are included.

  In the first step, a carbon nanotube structure is provided.

  The structure of the carbon nanotube structure and the manufacturing method thereof are the above-described structure of the carbon nanotube structure and the manufacturing method thereof.

  In the second step, a first electrode and a second electrode are provided, and the first electrode and the second electrode are electrically connected to the carbon nanotube structure to form a surface heat source.

  The method of electrically connecting the first electrode and the second electrode to the carbon nanotube structure is not limited, and may be electrically connected to the carbon nanotube structure by a lead wire, or You may install directly on the surface of a carbon nanotube structure. The first electrode and the second electrode may be disposed on the same surface or different surfaces of the carbon nanotube structure. The first electrode and the second electrode are disposed at a predetermined distance, have a predetermined resistance between the first electrode and the second electrode, and the first electrode and the second electrode are short-circuited. Can be prevented. Since the carbon nanotube structure itself has excellent adhesiveness, the first electrode and the second electrode are bonded to the surface of the carbon nanotube structure using the adhesiveness. Therefore, the first electrode and the second electrode can be well electrically connected to the carbon nanotube structure. Moreover, you may adhere | attach the said 1st electrode and said 2nd electrode on the surface of the said carbon nanotube structure using conductive adhesives, such as a silver paste, for example.

10, 20, 30, 40, 50 Surface heat source 12, 22, 32, 42, 52 First electrode 14, 24, 34, 44, 54 Second electrode 15, 25 Protective layer 16, 26, 36, 46, 56 Heating Element 17, 27 Reflective layer 18, 28, 38, 48, 58 Substrate 143a Carbon nanotube film 143b Carbon nanotube segment 145 Carbon nanotube 160 Non-twisted carbon nanotube linear structure 170 Twisted carbon nanotube linear structure 161, 171 Carbon Nanotube wire

Claims (8)

A heating element and at least two electrodes electrically connected to the heating element;
The heating element includes a carbon nanotube structure;
A surface heat source, wherein the carbon nanotube structure includes a plurality of carbon nanotubes.   2. The surface heat source according to claim 1, wherein in the carbon nanotube structure, the plurality of carbon nanotubes are connected by an intermolecular force and are uniformly distributed.   The surface heat source according to any one of claims 1 to 2, wherein the carbon nanotube structures are aligned and arranged in the carbon nanotube structure.   The surface heat source according to claim 1, wherein the carbon nanotubes are arranged without being oriented in the carbon nanotube structure.   The carbon nanotube structure includes at least one carbon nanotube film, at least one carbon nanotube linear structure, or a composite structure of a carbon nanotube film and a carbon nanotube linear structure. The surface heat source according to any one of the above. The carbon nanotube structure comprises at least two laminated carbon nanotube films;
The surface heat source according to any one of claims 1 to 5, wherein an angle formed by the carbon nanotubes between adjacent carbon nanotube films is 0 ° to 90 °.   The surface heat source according to claim 1, wherein the heating element is installed on a substrate.   The surface heat source according to claim 7, comprising a reflective layer, wherein the reflective layer is disposed on the surface of the substrate, and is used for reflecting heat released from the heating element.