Thermocouples and temperature sensors

Abstract

To provide a thermocouple with excellent durability, and a temperature sensor equipped with it. [Solution] A thermocouple having a pair of conductive wires made up of two conductive wires, wherein at least one of the conductive wires is a conductive wire containing nanocarbon; a thermocouple in which the pair of conductors is a pair of conductors made up of two conductors with different Seebeck coefficients, or a pair of conductors made up of one conductor having two regions with different Seebeck coefficients; a thermocouple in which the measurement point of the thermocouple is located at the joint of the pair of conductors, the stitched part of the pair of conductors, the twisted part of the pair of conductors, the woven part of the pair of conductors, or the boundary between two regions of one conductor having two regions with different Seebeck coefficients; and a temperature sensor equipped therewith.

Description

[Technical Field]

[0001] This disclosure relates to thermocouples and temperature sensors. [Background technology]

[0002] Thermocouples have traditionally been used as temperature sensors. Conventional thermocouples typically utilize dissimilar metal wires as conductors. On the other hand, film-type thermocouples using nanocarbons such as carbon nanotubes and graphene are also known (for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2018-197696 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] However, thermocouples that use dissimilar metal wires as conductors have poor durability because the dissimilar metal wires have low flexibility. Because film-type thermocouples have metal electrodes or other metal components at the measurement point, the plasticity of the measurement point is reduced. As a result, peeling of the metal components may occur, leading to poor durability. In particular, for applications where the temperature to be measured is a moving component, such as temperature sensors for measuring mold temperature, the thermocouples used are often subjected to repeated stress, and there is a current demand for greater durability.

[0005] Therefore, the objective of this disclosure is to provide a thermocouple with excellent durability and a temperature sensor equipped therewith. [Means for solving the problem]

[0006] The means for solving the problem include the following: <1> A thermocouple having a pair of conductive wires consisting of two conductive wires, A thermocouple in which at least one of the pair of conductive wires is a conductive wire containing nanocarbon. <2> The nanocarbon is a carbon nanotube. <1> The thermocouple described above. <3> A thermocouple having a pair of conductors, The pair of conductors, A pair of conductive wires consisting of two conductive wires containing different types of conductive nanocarbon and having different Seebeck coefficients. A pair of conductors consisting of two conductors containing the same conductive type of nanocarbon but with different Seebeck coefficients, or A pair of conductors comprising one conductor having two regions with different Seebeck coefficients, containing nanocarbons of different conductivity types or nanocarbons of the same conductivity type. A thermocouple. <4> The aforementioned nanocarbon of the same conductive type is P-type nanocarbon. <3> The thermocouple described above. <5> The nanocarbon is a carbon nanotube. <3> The thermocouple described above. <6> A thermocouple having a pair of conductors, The measurement point of the aforementioned thermocouple is A bonding portion of a pair of conductors consisting of two conductors having different Seebeck coefficients, containing nanocarbons of different conductivity types or the same conductivity type. A joint between two conductors, each containing nanocarbons of different conductivity types or the same conductivity type, and having different Seebeck coefficients. A twisted portion of a pair of conductors consisting of two conductors with different Seebeck coefficients, containing nanocarbons of different conductivity types or the same conductivity type. A pair of conductive woven sections consisting of two conductors containing different types of conductive nanocarbons or the same type of conductive nanocarbon, but with different Seebeck coefficients, or A boundary portion between said two regions of a single conductor that includes nanocarbons of different conductivity types or nanocarbons of the same conductivity type and has two regions with different Seebeck coefficients, A thermocouple comprising at least. <7> The thermocouple according to <6>, wherein the nanocarbons of the same conductivity type are P-type nanocarbons. <8> The thermocouple according to <6>, wherein the nanocarbon is a carbon nanotube. <9> A temperature sensor comprising the thermocouple according to any one of <1> to <8>.

Effects of the Invention

[0007] According to the present disclosure, a thermocouple excellent in durability and a temperature sensor including the same can be provided.

Brief Description of Drawings

[0008] [Figure 1] It is a schematic configuration diagram showing an example of the temperature sensor of the present disclosure. [Figure 2] It is a schematic configuration diagram showing an example of the thermocouple according to the first embodiment of the present disclosure. [Figure 3] It is a schematic configuration diagram showing an example of the thermocouple according to the second embodiment of the present disclosure. [Figure 4] It is a schematic configuration diagram showing an example of the thermocouple according to the third embodiment of the present disclosure. [Figure 5] It is a schematic configuration diagram showing an example of the thermocouple according to the fourth embodiment of the present disclosure. [Figure 6] It is a schematic configuration diagram showing an example of the thermocouple according to the fifth embodiment of the present disclosure.

Mode for Carrying Out the Invention

[0009] Hereinafter, embodiments that are an example of the present disclosure will be described. These descriptions and examples are for illustrating the embodiments, and do not limit the scope of the invention. In the numerical ranges described stepwise within this specification, one numerical range is described. The upper or lower limits may be replaced with the upper or lower limits of other stepped numerical ranges. Furthermore, within the numerical ranges described herein, the upper or lower limits of those ranges may be replaced with the values ​​shown in the examples. Each component in the composition may contain multiple types of the relevant substance. When referring to the amount of each component in a composition, if there are multiple substances corresponding to each component in the composition, unless otherwise specified, it refers to the total amount of those multiple substances present in the composition.

[0010] <Temperature sensor / thermocouple> The temperature sensor of this disclosure comprises a thermocouple, and the thermocouple is one of the thermocouples described in the First to Third Disclosures below.

[0011] The thermocouple of the first disclosure has a pair of conductive wires consisting of two conductive wires. Furthermore, in the first thermocouple of this disclosure, at least one of the pair of conductive wires is a conductive wire containing nanocarbon. In the thermocouple of the first disclosure, a conductive wire containing nanocarbon, which has flexibility and strength, is applied to at least one of the pair of conductive wires. This makes one or both of the conductive wires constituting the thermocouple less likely to break even when subjected to repeated stress. As a result, the durability of the thermocouple is improved.

[0012] The thermocouple of the second disclosure has a pair of conductors. Furthermore, in the thermocouple of the second disclosure, the pair of conductors consists of a pair of conductive wires comprising two conductive wires containing different conductive types and having different Seebeck coefficients, a pair of conductors comprising two conductors containing the same conductive type and having different Seebeck coefficients, or a single conductor comprising different conductive types of nanocarbon or the same conductive type and having two regions with different Seebeck coefficients. In the thermocouple of the second disclosure, a conductive wire or conductor containing nanocarbon, which has flexibility and strength, is applied to a pair of conductive wires or a pair of conductors. As a result, the pair of conductive wires or a pair of conductors constituting the thermocouple becomes less likely to break even when subjected to repeated stress. Therefore, the durability of the thermocouple is improved.

[0013] The thermocouple of the third disclosure has a pair of conductors. Furthermore, in the thermocouple of the third disclosure, the measurement point of the thermocouple is A bonding portion of a pair of conductors consisting of two conductors having different Seebeck coefficients, containing nanocarbons of different conductivity types or the same conductivity type. A joint between two conductors, each containing nanocarbons of different conductivity types or the same conductivity type, and having different Seebeck coefficients. A twisted portion of a pair of conductors consisting of two conductors with different Seebeck coefficients, containing nanocarbons of different conductivity types or the same conductivity type. A pair of conductive woven sections consisting of two conductors containing different types of conductive nanocarbons or the same type of conductive nanocarbon, but with different Seebeck coefficients, or The boundary between two regions of a single conductor having two regions with different Seebeck coefficients, containing nanocarbons of different conductivity types or nanocarbons of the same conductivity type. It consists of at least these. In the thermocouple of the third disclosure, the measurement points are the knot, stitched, twisted, braided, and boundary sections of the above configuration. In the knot, a pair of conductors are tied together; in the stitched section, a pair of conductors are stitched together; in the twisted section, a pair of conductors are twisted together; and in the braided section, a pair of conductors are woven or knitted together. The boundary section is composed of a single conductor. By applying these parts to the measurement points, the strength of the measurement points is increased compared to conventional measurement points where dissimilar metal wires are joined together. Furthermore, these parts do not require metal components such as metal electrodes, meaning they can be constructed without metal components, and the metal electrodes that serve as measurement points do not peel off as in conventional film-type thermocouples. Therefore, the thermocouple is less likely to break even when repeated stress is applied to its measurement points. The durability of the thermocouple is improved.

[0014] Here, "two conductors or two conductive wires with different Seebeck coefficients" is preferably two conductors or two conductive wires whose difference in Seebeck coefficients is, for example, 1 μV / K or more in absolute value (preferably 10 μV / K or more, more preferably 20 μV / K or more). Similarly, "two regions with different Seebeck coefficients in a single conductor" are preferably two regions where the difference in Seebeck coefficients is, for example, 1 μV / K or more in absolute value (preferably 10 μV / K or more, more preferably 20 μV / K or more). Furthermore, a larger absolute value in the difference between Seebeck coefficients is preferable because it results in a higher amount of electromotive force generated by heat.

[0015] The Seebeck coefficient is measured and calculated as follows: The thermoelectric power generated is measured using a thermoelectric properties measuring device while one end of the conductor, conductive wire, or area of ​​a conductor being measured is heated to create a temperature difference of 0.5 to 30°C between the two ends of the conductor or conductive wire. Then, preferably, the temperature difference is varied to about three levels during the measurement, and the Seebeck coefficient is calculated from the arithmetic mean of the obtained thermoelectric powers.

[0016] The following describes in detail an embodiment of a temperature sensor and thermocouple, which is an example of the present disclosure, with reference to the drawings.

[0017] <Temperature sensor> As shown in Figure 1, the temperature sensor 10 according to this embodiment includes, for example, a thermocouple 12, an amplifier 14 that amplifies the analog signal (electromotive force signal) from the thermocouple 12, and an analog-to-digital converter 16 that converts the amplified analog signal (electromotive force signal) into a digital signal (electrical pulse or optical pulse, etc.). The temperature sensor 10 is connected to a temperature measuring instrument 18.

[0018] Here, the measurement points of thermocouple 12 are comprised of the following parts. At these parts, when the conductive wire containing nanocarbon heats up, an electromotive force is generated by the heat produced. 1) Contact portion of a pair of conductive wires consisting of two conductive wires containing different types of conductive nanocarbon and having different Seebeck coefficients 2) Contact area of ​​a pair of conductors consisting of two conductors that contain the same conductive type of nanocarbon but have different Seebeck coefficients 3) The boundary between two regions of a pair of conductors, each consisting of a single conductor containing nanocarbons of different conductivity types or nanocarbons of the same conductivity type, and having two regions with different Seebeck coefficients.

[0019] The temperature sensor 10 is not limited to the above configuration other than the thermocouple 12, and any well-known temperature sensor configuration may be used.

[0020] <Thermocouple> The thermocouples 110, 210, 310, 410, and 510 according to the first to fifth embodiments, which are applied to thermocouple 12, will be described below.

[0021] (First Embodiment) As shown in Figure 2, the thermocouple 110 according to the first embodiment has, for example, a pair of conductors 112. The pair of conductors 112 consists of two conductors 114A and 114B that contain nanocarbons of different conductivity types or the same conductivity type, and have different Seebeck coefficients. When two conductors 114A and 114B contain nanocarbon of the same conductivity type, the Seebeck coefficients of the two conductors 114A and 114B can be made different by changing either the type or amount of dopant used to dope the nanocarbon in the two conductors 114A and 114B.

[0022] The combinations of the two conductors 114A and 114B are as follows: 1) A combination of a P-type conductor 114A containing P-type nanocarbon that is either undoped or doped with a P-type dopant, and an N-type conductor 114B containing N-type nanocarbon that is doped with an N-type dopant. 2) A combination of a p-type conductor 114A containing p-type nanocarbon that is either undoped or doped with a p-type dopant, and a p-type conductor 114B containing p-type nanocarbon that is doped with more p-type dopant than the p-type nanocarbon contained in p-type conductor 114A. 3) A combination of an N-type conductor 114A containing N-type nanocarbons doped with an N-type dopant, and an N-type conductor 114B containing N-type nanocarbons doped with more N-type dopant than the N-type nanocarbons contained in the N-type conductor 114A.

[0023] Among these combinations, the combination of P-type conductor 114A and P-type conductor 114B is preferred because it is less prone to deterioration of carrier characteristics and has high durability. In other words, it is preferable that the nanocarbons of the same conductivity type be P-type nanocarbons.

[0024] The two conductors 114A and 114B may each be, for example, conductive wires such as nanocarbon yarn or conductive strips such as nanocarbon ribbons. The two conductors 114A and 114B may be of the same type or different types.

[0025] Details of the two conductors 114A and 114B will be described later.

[0026] The measurement point 116 of the thermocouple 110 is formed at the joint 118 of a pair of conductors 112 consisting of two conductors 114A and 114B. Specifically, one end of the two conductors 114A and 114B is connected to each other, and this joint 118 constitutes the measurement point 116 of the thermocouple 110.

[0027] Examples of knots 118 include knots formed by a single knot or figure-eight knot between two conductors 114A and 114B; knots formed by a square knot, a single tie, or a double tie between two conductors 114A and 114B; knots formed by wrapping one conductor 114B around the other conductor 114A and making a single or double knot; and other knots formed by connecting two conductors 114A and 114B using well-known methods.

[0028] The knot 118 can also be exemplified as a knot formed by tying together two conductors 114A and 114B with a binding material while keeping them in contact. Examples of knotting materials include nanocarbon yarn, nanocarbon ribbon, yarn or ribbon of natural fibers (silk, cotton, etc.), yarn or ribbon of chemical fibers (polyester fiber, nylon fiber, etc.), and blended yarns of natural and chemical fibers.

[0029] In Figure 2, an example is shown in which the measurement point 116 of the thermocouple 110 is formed by a knot 118 created by single-knotting two bundled conductive wires, with the two conductive elements 114A and 114B being the two conductive elements.

[0030] (Second embodiment) The thermocouple 210 according to the second embodiment has a pair of conductors 212, as shown in Figure 3. The pair of conductors 212 consists of two conductors 214A and 214B that contain nanocarbons of different conductivity types or the same conductivity type, and have different Seebeck coefficients. When two conductors 214A and 214B contain nanocarbon of the same conductivity type, the Seebeck coefficients of the two conductors 214A and 214B can be made different by changing either the type and amount of nanocarbon, or the type and amount of dopant used to dope the nanocarbon. The combination of the two conductors 214A and 214B is the same as the combination of the two conductors 114A and 114B in the first embodiment.

[0031] In the thermocouple 210, the two conductors 214A and 214B are, for example, conductive wires such as nanocarbon yarn, conductive ribbons such as nanocarbon ribbons or nanocarbon-containing films, respectively. The two conductors 214A and 214B may be of the same type or different types. However, the conductive wire is applied to only one of the two conductors 214A or 214B. The two conductors 214A and 214B may be, for example, a woven or knitted fabric in which conductive wires are braided or woven.

[0032] Details of the two conductors, 214A and 214B, will be described later.

[0033] The measurement point 216 of the thermocouple 210 is formed by the seam 218 of a pair of conductors 212, which consist of two conductors 214A and 214B. Specifically, one end of the two conductors 214A and 214B is sewn together, and this seam 218 constitutes the measurement point 216 of the thermocouple 210.

[0034] The seam 218 can be exemplified by a seam formed by sewing together two conductive materials 214A and 214B while they are stacked on top of each other. Examples of sewing materials include nanocarbon yarn, nanocarbon ribbon, yarn or ribbon made from natural fibers (silk, cotton, etc.), yarn or ribbon made from chemical fibers (polyester fiber, nylon fiber, etc.), and blended yarns of natural and chemical fibers.

[0035] The stitched portion 218 can also be exemplified by applying a conductive strip such as a nanocarbon ribbon or nanocarbon-containing film as one of the conductors 214A, and a conductive wire such as a nanocarbon yarn as the other conductor 214B, with the conductive wire sewn into the conductive strip.

[0036] Here, examples of sewing methods include well-known stitches such as running stitch, basting stitch, backstitch, double backstitch, and overcast stitch.

[0037] Figure 3 shows an example in which two conductors 214A and 214B are stacked on top of each other, and the measurement point 216 of the thermocouple 210 is formed at the seam 218 sewn together with a sewing material. Here, in Figure 3, 218A represents the sewing material.

[0038] (Third embodiment) The thermocouple 310 according to the third embodiment has a pair of conductors 312, as shown in Figure 4. The pair of conductors 312 consists of two conductors 314A and 314B that contain nanocarbons of different conductivity types or the same conductivity type, and have different Seebeck coefficients. When two conductors 314A and 314B contain nanocarbon of the same conductivity type, the Seebeck coefficients of the two conductors 314A and 314B can be made different by changing either the type and amount of nanocarbon, or the type and amount of dopant used to dope the nanocarbon. The combination of the two conductors 314A and 314B is the same as the combination of the two conductors 114A and 114B in the first embodiment.

[0039] In thermocouple 310, the two conductors 314A and 314B are each, for example, conductive wires such as nanocarbon yarn. The two conductors 314A and 314B may be the same type of conductor or different types of conductors.

[0040] Details of the two conductors 314A and 314B will be described later.

[0041] The measurement point 316 of the thermocouple 310 is formed by a twisted portion 318 of a pair of conductors 312 consisting of two conductors 314A and 314B. Specifically, one end of the two conductors 314A and 314B are twisted together, and this twisted portion 318 constitutes the measurement point 316 of the thermocouple 310. Alternatively, the entirety of the two conductors 314A and 314B may be twisted together.

[0042] The twisted portion 318 can be exemplified by a twisted portion in which one end of two conductors 314A and 314B is bundled together, and the bundled portion is twisted so that one end of each conductor 314A and 314B wraps around each other.

[0043] (Fourth embodiment) The thermocouple 410 according to the fourth embodiment has a pair of conductors 412, as shown in Figure 5. The pair of conductors 412 consists of two conductors 414A and 414B that contain nanocarbons of different conductivity types or the same conductivity type, and have different Seebeck coefficients. When two conductors 414A and 414B contain nanocarbon of the same conductivity type, the Seebeck coefficients of the two conductors 414A and 414B can be made different by changing either the type and amount of nanocarbon, or the type and amount of dopant used to dope the nanocarbon. The combination of the two conductors 414A and 414B is the same as the combination of the two conductors 114A and 114B in the first embodiment.

[0044] In the thermocouple 410, the two conductors 414A and 414B are each, for example, conductive wires such as nanocarbon yarn. The two conductors 414A and 414B may be the same type of conductor or different types of conductors.

[0045] Details of the two conductors 414A and 414B will be described later.

[0046] The measurement point 416 of the thermocouple 410 is formed by a braided portion 418 of a pair of conductors 412 consisting of two conductors 414A and 414B. Specifically, one end of the two conductors 414A and 414B is braided or woven into the braided portion 418, which constitutes the measurement point 416 of the thermocouple 410. Alternatively, the entirety of the two conductors 414A and 414B may be braided or woven into the braid.

[0047] The knitted section 418 can be exemplified by a knitted section in which two conductive materials 414A and 414B are knitted together using well-known knitting methods such as plain knit, jersey knit, or stockinette knit. The woven section 418 can be exemplified by a section in which two conductive materials 414A and 414B are woven together using well-known weaving methods such as plain weave, twill weave, or satin weave.

[0048] (Fifth embodiment) The thermocouple 510 according to the fifth embodiment has, for example, a pair of conductors 512, as shown in Figure 6. The pair of conductors 512 consists of one conductor 514 having two regions 514A and 514B with different Seebeck coefficients, each containing nanocarbons of different conductivity types or the same conductivity type. When two regions 514A and 514B of a single conductor 514 contain nanocarbon of the same conductivity type, the Seebeck coefficients of the two regions 514A and 514B of a single conductor 514 can be made different by changing either the type and amount of nanocarbon or the type and amount of dopant used to dope the nanocarbon in the two regions 514A and 514B.

[0049] The combinations of two regions 514A and 514B in a single conductor 514 are as follows: 1) A combination of a P-type region 514A containing P-type nanocarbon that is either undoped or doped with a P-type dopant, and an N-type region 514B containing N-type nanocarbon that is doped with an N-type dopant. 2) A combination of a P-type region 514A containing P-type nanocarbons that are either undoped or doped with a P-type dopant, and a P-type region 514B containing P-type nanocarbons that are doped with more P-type dopant than the P-type nanocarbons contained in P-type region 514A. 5) A combination of an N-type region 514A containing N-type nanocarbons doped with an N-type dopant, and an N-type region 514B containing N-type nanocarbons that are doped with more N-type dopant than the N-type nanocarbons contained in N-type region 514A.

[0050] Among these combinations, the combination of P-type region 514A and P-type region 514B is preferred because it is less prone to deterioration of carrier characteristics and has high durability. In other words, it is preferable that the same conductive nanocarbon is P-type nanocarbon.

[0051] In the thermocouple 510, one of the conductors 514 may be a conductive wire such as nanocarbon yarn, a conductive ribbon such as nanocarbon ribbon, or a conductive band such as a nanocarbon-containing film. Details of one of the conductors 514 will be described later.

[0052] The measurement point 516 of the thermocouple 5310 is composed of the boundary 518 between two regions 514A and 514B with different Seebeck coefficients in a single conductor 514. Specifically, for example, the conductor 514 is curved or bent starting from the boundary 518, the part with the highest curvature is designated as the boundary 518, and this boundary 518 is designated as the measurement point 516 of the thermocouple 5310.

[0053] (Other embodiments) In the first to fifth embodiments described above, each thermocouple was described as being provided independently. However, each thermocouple 110, 210, 310, 410, and 510 may also be provided on a flexible substrate or sewn into a cloth substrate. When thermocouples 110, 210, 310, 410, and 510 are provided on a flexible substrate, carbon-containing films such as nanocarbon single-layer films and nanocarbon-containing resin films can be suitably used as the conductor. In the case where thermocouples 110, 210, 310, 410, and 510 are sewn into a fabric base material, conductive wires such as nanocarbon yarn and conductive strips such as nanocarbon ribbons can be suitably used as the conductors.

[0054] In the first to fifth embodiments described above, each of the two conductors constituting each thermocouple 110, 210, 310, 410, 510, or one conductor, may have one or more other conductors having the same carrier characteristics.

[0055] <Conductive material> The details of the conductors applied to thermocouples 110, 210, 310, 410, and 510 according to the first to third embodiments will be described below. Reference numerals will be omitted in the description.

[0056] The conductor contains nanocarbon. For example, if we take single-walled carbon nanotubes as the nanocarbon, the nanocarbon content relative to the conductor is preferably 0.2% by mass or more, from the viewpoint of conductivity and durability. In particular, the conductor is preferably a conductor that contains nanocarbon as its main component. Specifically, the conductor is preferably a conductor that contains nanocarbon in an amount of 50% by mass or more, 90% by mass or more, 95% by mass or more, or 99% by mass or more, relative to the conductor, and ideally in an amount of 100% by mass.

[0057] Examples of conductors include conductive wires and conductive strips. Examples of conductive wires include nanocarbon yarn. Examples of conductive strips include nanocarbon ribbons and nanocarbon-containing films. Here, nanocarbon-containing films include nanocarbon-only films and nanocarbon-containing resin films. Examples of resins for nanocarbon-containing resin films include well-known binder resins such as polyimide resins, polyester resins, and silicone resins.

[0058] The conductive material may also be covered with an insulating resin coating layer. Examples of well-known insulating resins for the insulating resin coating layer include polyethylene, polyolefins (polyethylene, polypropylene, etc.), polystyrene, poly(meth)acrylic acid esters, styrene-(meth)acrylic acid ester copolymers, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, straight silicone resin or its modified products, fluororesin, polycarbonate, phenolic resin, epoxy resin, and polyurethane resin.

[0059] (Nanocarbon) As the nanocarbon material constituting the conductor, carbon nanotubes (CNTs) are preferred. Carbon nanotubes are preferred because they have a high thermoelectric power and are easily formed into linear structures. Carbon nanotubes may be single-walled carbon nanotubes (SWCNTs) in which a single carbon film (graphene sheet) is wound into a cylindrical shape. Carbon nanotubes may also be multi-walled carbon nanotubes (MWCNTs), such as double-walled, triple-walled, or quadruple-walled carbon nanotubes, in which two graphene sheets are wound concentrically. Considering thermoelectric properties, carbon nanotubes with 10 layers or less are preferable. Single-walled carbon nanotubes are preferable because they easily provide high thermoelectric properties. Multi-walled carbon nanotubes are preferable because they are inexpensive and easy to mass-produce. Single-walled and multi-walled carbon nanotubes can also be used in combination. Furthermore, carbon nanotubes may be metallic carbon nanotubes, semiconducting carbon nanotubes, or a mixture of both. The method for producing carbon nanotubes is not particularly limited. Carbon nanotubes can be produced by methods such as arc discharge, chemical vapor deposition (CVD), and laser ablation. Commercially available carbon nanotubes may also be used.

[0060] Nanocarbon may also be graphene. By inserting carriers between two layers of graphene, graphene can be used as a semiconductor material.

[0061] Other examples of nanocarbons include carbon nanorods, carbon nanowires, graphene, and fullerenes.

[0062] --Type P Dopant-- P-type dopants that can be doped into nanocarbons refer to dopants whose Seebeck coefficient in the doped nanocarbon is a positive value, and include nonionic compounds or ionic compounds. P-type dopants are preferable to N-type dopants in terms of durability. In particular, when the solvent for the P-type dopant solution used for doping is water, a nonionic compound is preferred as the P-type dopant. On the other hand, if the solvent for the P-type dopant solution used for doping is an organic solvent, an ionic compound is preferred as the P-type dopant.

[0063] Examples of nonionic compounds that are P-type dopants include tetracyanoquinodimethane (TCNQ) derivatives (2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane, 2,5-dimethyl-7,7,8,8-tetracyanoquinodimethane, 2-fluoro-7,7,8,8-tetracyanoquinodimethane, 2,5-difluoro-7,7,8,8-tetracyanoquinodimethane, etc.), Benzoquinone derivatives (2,3-dichloro-5,6-dicyano-p-benzoquinone, tetrafluoro-1,4-benzoquinone, etc.) Quinosaline derivatives (5,8H-5,8-bis(dicyanomethylene)quinoxaline, dipyradino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11-hexacarbonnitrile, etc.) Examples include 9H-carbazole, 9H-carbazole-4-ol, and pyrazine.

[0064] As the ionic compound that is a P-type dopant, for example, perchlorate ion (ClO 4- ), permanganate ion (MnO 4- ), iodate ion (IO 3- ), thiocyanate ion (SCN - ), hexafluorophosphate ion (PF 6- ), tetrafluoroborate ion (BF 4- ), trifluoromethanesulfonate anion (TfO - ), bis(trifluoromethanesulfonyl)amine anion (TFSI - ), iodide ion (I - ), bromide ion (Br - ), chloride ion (Cl - ), nitrate ion (NO 3- ) or tosylate ion (Tos - ) include hydracids and metal salts thereof. Examples of the metal salts include silver salts and copper salts.

[0065] --N-type dopant-- As an N-type dopant that can be doped into nanocarbon, it means a dopant that makes the Seebeck coefficient of the doped nanocarbon a negative value, and examples thereof include nonionic compounds or ionic compounds. In particular, when the solvent of the N-type dopant solution for doping is water, a nonionic compound is preferable as the N-type dopant. On the other hand, when the solvent of the N-type dopant solution for doping is an organic solvent, an ionic compound is preferable as the N-type dopant.

[0066] As the nonionic compound that is an N-type dopant, polyalkyleneimine is preferable. As the polyalkyleneimine, a polyalkyleneimine having a structural unit with an alkylene group having 1 to 6 carbon atoms (preferably 1 to 4 carbon atoms, more preferably 1 to 2 carbon atoms) is preferable, and polyethyleneimine is more preferable.

[0067] Examples of ionic compounds that act as N-type dopants include alkali metal salts (salts of lithium, sodium, potassium, or cesium, etc.) and alkylammonium salts (salts of tetraethylammonium ions, tetrabutylammonium ions, etc.). Among these, alkylammonium halides are preferred as ionic compounds, and the following compounds are examples.

[0068] [ka]

[0069] Examples of N-type dopants include complexes of alkali metal salts and cyclic ethylene oxides. Ions found in alkali metal salts include hydroxyl ions (OH) - ), alkoxy ions (CH3O - CH3CH2O - i-PrO - and t-BuO - (etc.), thioions (SH) - and alkylthioions (CH3S - and C2H5S - etc.), cyanuryl ions (CN - ), carboxyl ion (CH3COO - Examples include: Examples of alkali metals contained in alkali metal salts include lithium, sodium, and potassium. Examples of cyclic ethylene oxides include crown ethers.

[0070] Examples of N-type dopants include phosphine compounds such as triphenylphosphine, trioctylphosphine, and 1,3-bis(diphenylphosphine)propane.

[0071] --doping-- One method for doping a conductor (or a portion of a conductor) containing nanocarbon with a dopant is to immerse the heated conductor (or a portion of a conductor) in a dopant solution. This method allows for simple and low-cost doping. After doping, washing is performed. However, doping with a dopant may be performed by methods such as coating or brushing.

[0072] From the viewpoint of reducing environmental impact, the solvent of the dopant solution preferably contains water as its main component. The solvent containing water as its main component may also contain water-soluble organic solvents such as alcohols (methanol, ethanol, propanol, etc.). Note that "water as the main component" means, for example, that the proportion of water is 50% by mass (preferably 70% by mass, or 90% by mass) or more of the total solvent. However, the solvent of the dopant solution may have an organic solvent as its main component. Examples of organic solvents include alcohols (ethanol, propanol, etc.), acetone, methyl ethyl ketone, and butyl acetate. Having an organic solvent as the main component means, for example, that the proportion of the organic solvent is 50% by mass (preferably 70% by mass, or 90% by mass) or more of the total solvent. [Explanation of symbols]

[0073] 10 Temperature sensors 12 Thermocouples 14 Amplifier 16 Digital Converters 18. Temperature measuring instrument 110, 210, 310, 410, 510 thermocouples 112,212,312,412,412 pairs of conductors 114A,114B,214A,214B,314A,314B,414A,414B,514 Conductor

Claims

1. A thermocouple having a pair of conductive wires consisting of two conductive wires, A thermocouple in which at least one of the pair of conductive wires is a conductive wire containing nanocarbon.

2. The thermocouple according to claim 1, wherein the nanocarbon is a carbon nanotube.

3. A thermocouple having a pair of conductors, The pair of conductors, A pair of conductive wires consisting of two conductive wires containing different types of conductive nanocarbon and having different Seebeck coefficients. A pair of conductors consisting of two conductors containing the same conductive type of nanocarbon but with different Seebeck coefficients, or A pair of conductors comprising one conductor having two regions with different Seebeck coefficients, containing nanocarbons of different conductivity types or nanocarbons of the same conductivity type. A thermocouple.

4. The thermocouple according to claim 3, wherein the aforementioned same conductive nanocarbon is P-type nanocarbon.

5. The thermocouple according to claim 3, wherein the nanocarbon is a carbon nanotube.

6. A thermocouple having a pair of conductors, The measurement point of the aforementioned thermocouple is A bonding portion of a pair of conductors consisting of two conductors having different Seebeck coefficients, containing nanocarbons of different conductivity types or the same conductivity type. A joint between two conductors, each containing nanocarbons of different conductivity types or the same conductivity type, and having different Seebeck coefficients. A twisted portion of a pair of conductors consisting of two conductors with different Seebeck coefficients, containing nanocarbons of different conductivity types or the same conductivity type. A pair of conductive materials consisting of two conductors with different Seebeck coefficients, or containing nanocarbons of different conductivity types or the same conductivity type. The boundary between two regions of a single conductor having two regions with different Seebeck coefficients, containing nanocarbons of different conductivity types or nanocarbons of the same conductivity type. A thermocouple composed of at least these elements.

7. The thermocouple according to claim 6, wherein the aforementioned nanocarbon of the same conductive type is P-type nanocarbon.

8. The thermocouple according to claim 6, wherein the nanocarbon is a carbon nanotube.

9. A temperature sensor having a thermocouple according to any one of claims 1 to 8.

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