Hydrogen sensor, hydrogen detection system, and sheet for hydrogen sensor

Abstract

To provide a hydrogen sensor that can detect a hydrogen gas even in a wide range and can locate a leakage place of hydrogen.SOLUTION: Provided is a hydrogen sensor that has a board, a sensitive film that is disposed on a first surface of the board and contains a catalyst for dissociating a hydrogen gas to a hydrogen atom and a tungsten oxide, a control section for detecting a change in electric resistance, a first bus electrode and a second bus electrode that are disposed on the first surface of the board and are connected to the control section, first multiple sensor electrodes that are disposed on the first surface of the board while abutting on the sensitive film and are connected to the first bus electrode, and second multiple sensor electrodes that are disposed on the first surface of the board while abutting on the sensitive film and are connected to the second bus electrode, and the first sensor electrode and the second sensor electrode are alternately disposed with a gap permitting detection of a change in electric resistance of the sensitive film.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a hydrogen sensor, a hydrogen detection system, and a sheet for a hydrogen sensor. [Background technology]

[0002] In recent years, there has been a desire to utilize clean and recyclable energy sources from the perspective of protecting the global environment and preventing the depletion of fossil fuels. In particular, research into the use of hydrogen gas as an energy source has been actively conducted, focusing on fuel cells. However, the explosive limit concentration of hydrogen gas ranges widely, from 4% to 75%, and in order to popularize hydrogen gas as an energy source, it is essential to develop safety devices to prevent hydrogen leakage, as well as to handle hydrogen storage and transportation.

[0003] For example, odorization, which is used in city gas, can be considered, but in the case of hydrogen gas, problems such as poisoning of fuel cells and deterioration of gas turbines arise. Therefore, safety measures that replace odorization are required. Therefore, to ensure safety, hydrogen sensors that can detect hydrogen gas leaks have become extremely important.

[0004] Conventional hydrogen sensors mainly use the catalytic combustion or semiconductor method. Catalytic combustion hydrogen sensors use a heater to heat a catalytic metal such as platinum or palladium, and oxidize hydrogen gas that comes into contact with the catalyst with oxygen in the air. The heat generated by this oxidation of hydrogen gas is detected electrically as a change in the conductivity of the catalytic metal. Semiconductor hydrogen sensors detect changes in the electrical properties of the sensitive film due to the adsorption of hydrogen gas onto the sensitive film, i.e., changes in electrical resistance. Like catalytic combustion sensors, semiconductor hydrogen sensors are also used in a heated state. As such, conventional hydrogen sensors, such as those using catalytic combustion or semiconductor methods, involve heating, which poses a risk when used with hydrogen gas that requires explosion-proof measures.

[0005] Gasochromic hydrogen sensors have also been attracting attention in recent years. Gasochromic hydrogen sensors are equipped with a metal oxide such as tungsten trioxide, which changes color upon adsorption of hydrogen, and a catalyst such as platinum, which dissociates hydrogen gas into hydrogen atoms, and detect hydrogen gas optically. Because the electrical properties of metal oxides such as tungsten trioxide also change upon adsorption of hydrogen, gasochromic hydrogen sensors can also detect hydrogen gas electrically (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 4496204 [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-328108 Summary of the Invention [Problem to be solved by the invention]

[0007] Conventional hydrogen sensors, such as those based on catalytic combustion or semiconductor methods, detect hydrogen gas at the location where they are installed. As a result, they can only detect hydrogen gas within a narrow range, making it difficult to identify the location of a hydrogen leak.

[0008] The present disclosure has been made in consideration of the above-described circumstances, and has as its main object to provide a hydrogen sensor that can detect hydrogen gas over a wide range and can also identify the location of a hydrogen leak. [Means for solving the problem]

[0009] One embodiment of the present disclosure provides a hydrogen sensor comprising: a substrate; a sensitive membrane disposed on a first surface of the substrate and containing a catalyst that dissociates hydrogen molecules and tungsten oxide; a control unit that detects changes in electrical resistance; a first bus electrode and a second bus electrode disposed on the first surface of the substrate and connected to the control unit; a plurality of first sensor electrodes disposed on the first surface of the substrate in contact with the sensitive membrane and connected to the first bus electrode; and a plurality of second sensor electrodes disposed on the first surface of the substrate in contact with the sensitive membrane and connected to the second bus electrode, wherein the first sensor electrodes and the second sensor electrodes are alternately arranged at intervals that allow changes in the electrical resistance of the sensitive membrane to be detected.

[0010] Another embodiment of the present disclosure provides a hydrogen detection system using the hydrogen sensor described above.

[0011] Another embodiment of the present disclosure provides a roll-shaped hydrogen sensor sheet having a substrate, a sensitive membrane disposed on a first surface of the substrate and containing a catalyst that dissociates hydrogen molecules and tungsten oxide, a bus electrode disposed on the first surface of the substrate and arranged in a serpentine line, and a plurality of first sensor electrodes and a plurality of second sensor electrodes disposed on the first surface of the substrate in contact with the sensitive membrane and connected to the bus electrode, wherein the first sensor electrodes and the second sensor electrodes are alternately arranged at intervals that allow changes in the electrical resistance of the sensitive membrane to be detected. [Effects of the Invention]

[0012] The hydrogen sensor of the present disclosure has the advantage of being able to detect hydrogen gas over a wide range and also being able to identify the location of a hydrogen leak. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic plan view illustrating a hydrogen sensor according to the present disclosure. [Figure 2] 1 is a schematic plan view illustrating a hydrogen sensor according to the present disclosure. [Figure 3]1 is a schematic plan view illustrating a hydrogen sensor according to the present disclosure. [Figure 4] 1 is a schematic plan view illustrating a hydrogen sensor according to the present disclosure. [Figure 5] 1 is a schematic plan view illustrating a hydrogen sensor according to the present disclosure. [Figure 6] 1 is a schematic plan view illustrating a hydrogen sensor according to the present disclosure. [Figure 7] 1 is a schematic plan view illustrating a hydrogen sensor according to the present disclosure. [Figure 8] 1 is a schematic plan view illustrating a hydrogen sensor according to the present disclosure. [Figure 9] 1 is a schematic plan view illustrating a hydrogen sensor according to the present disclosure. [Figure 10] 1 is a schematic plan view illustrating a hydrogen sensor according to the present disclosure. [Figure 11] 1 is a schematic plan view illustrating a hydrogen sensor according to the present disclosure. [Figure 12] FIG. 1 is a schematic diagram illustrating a hydrogen detection system according to the present disclosure. [Figure 13] FIG. 1 is a schematic diagram illustrating a hydrogen detection system according to the present disclosure. [Figure 14] 1 is a schematic perspective view illustrating a sheet for a hydrogen sensor according to the present disclosure. [Figure 15] 1 is a schematic plan view illustrating a hydrogen sensor sheet according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0014] Below, embodiments of the present disclosure will be described with reference to the drawings and the like. However, the present disclosure can be implemented in many different forms, and should not be construed as being limited to the description of the embodiments exemplified below. Furthermore, to clarify the explanation, the drawings may schematically depict the width, thickness, shape, etc. of each component compared to the embodiments, but these are merely examples and do not limit the interpretation of the present disclosure. Furthermore, in this specification and each drawing, elements similar to those previously described with reference to the previous drawings will be designated by the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0015] In this specification, when expressing an aspect in which another component is placed on a certain component, the term "on the surface side" or "on the surface" is used, unless otherwise specified, and includes both a case in which another component is placed directly above or below a certain component so as to be in contact with the component, and a case in which another component is placed above or below a certain component with another component in between.

[0016] Furthermore, in this specification, terms such as "sheet," "film," and "plate" are not distinguished from one another solely based on differences in name. For example, the term "sheet" is used to include members also known as films and plates.

[0017] The hydrogen sensor, hydrogen detection system, and hydrogen sensor sheet according to the present disclosure will be described in detail below.

[0018] A. Hydrogen sensor The hydrogen sensor of the present disclosure comprises a substrate, a sensitive membrane disposed on a first surface of the substrate and containing a catalyst that dissociates hydrogen molecules and tungsten oxide, a control unit that detects changes in electrical resistance, a first bus electrode and a second bus electrode disposed on the first surface of the substrate and connected to the control unit, a plurality of first sensor electrodes disposed on the first surface of the substrate in contact with the sensitive membrane and connected to the first bus electrode, and a plurality of second sensor electrodes disposed on the first surface of the substrate in contact with the sensitive membrane and connected to the second bus electrode, wherein the first sensor electrodes and the second sensor electrodes are alternately arranged at intervals that allow changes in the electrical resistance of the sensitive membrane to be detected.

[0019] FIG. 1 is a schematic plan view showing an example of a hydrogen sensor in the present disclosure. As shown in FIG. 1, the hydrogen sensor 1 includes a substrate 2, a sensitive film 3 disposed on the first surface of the substrate 2 and containing a catalyst for dissociating hydrogen molecules and tungsten oxide, a control unit 4 for detecting a change in electrical resistance, a first bus electrode 5 and a second bus electrode 6 disposed on the first surface of the substrate 2 and connected to the control unit 4, a plurality of first sensor electrodes 7 disposed on the first surface of the substrate 2 in contact with the sensitive film 3 and connected to the first bus electrode 5, and a plurality of second sensor electrodes 8 disposed on the first surface of the substrate 2 in contact with the sensitive film 3 and connected to the second bus electrode 6. The first sensor electrodes 7 and the second sensor electrodes 8 are alternately arranged with an interval d1 capable of detecting a change in the electrical resistance of the sensitive film 3. In FIG. 1, the first sensor electrodes 7 and the second sensor electrodes 8 are a pair of comb-shaped electrodes.

[0020] The hydrogen sensor in the present disclosure is a hydrogen sensor that utilizes the fact that when a sensitive film containing a catalyst and tungsten oxide reacts with hydrogen, its electrical resistance decreases. The operating principle of the hydrogen sensor in the present disclosure will be described.

[0021] Tungsten oxide (WO3) has a high electrical resistance. Therefore, in an atmosphere where hydrogen is absent, the sensitive film has a high electrical resistance and is insulating. At this time, the first sensor electrode and the second sensor electrode are insulated and in a non-conductive state.

[0022] On the other hand, when hydrogen molecules come into contact with the catalyst, the hydrogen molecules are dissociatively adsorbed to generate hydrogen atoms. These hydrogen atoms reduce tungsten oxide (WO3) to form a non-stoichiometric compound (H x WO3 (0 < x < 1)). The non-stoichiometric compound (H x WO3) is in a mixed valence state of W 5+ and W 6+ and thus has a low electrical resistance. Therefore, in an atmosphere where hydrogen is present, the above-described reduction reaction of tungsten oxide occurs, the sensitive film has its electrical resistance decreased, and becomes conductive. At this time, the first sensor electrode and the second sensor electrode are short-circuited and become conductive.

[0023] A first bus electrode is connected to the first sensor electrode, a second bus electrode is connected to the second sensor electrode, and a control unit is connected to the first bus electrode and the second bus electrode, so that hydrogen gas can be detected by detecting changes in electrical resistance using the control unit.

[0024] As described above, conventional semiconductor-type or catalytic combustion-type hydrogen sensors require heating and can only detect hydrogen gas over a narrow range. In contrast, the reduction reaction of tungsten oxide described above does not require the supply of electricity. Therefore, the hydrogen sensor disclosed herein can be made large-area and can detect hydrogen gas over a relatively wide range at low cost. Therefore, by using the hydrogen sensor disclosed herein, hydrogen gas leaks can be detected not only in small devices such as fuel cells, but also in large facilities such as hydrogen production facilities, hydrogen pipelines, transport tankers, storage tanks, and hydrogen power generation facilities.

[0025] Furthermore, the electrical resistance of a conductor is proportional to its length. Therefore, as illustrated in FIG. 2 , the electrical resistance measured by the control unit 4 differs between the case where the reduction reaction of tungsten oxide described above occurs in region 10A, causing the electrical resistance of the sensitive film 3 to decrease and short-circuiting the first sensor electrode 7 and the second sensor electrode 8, and the case where the reduction reaction of tungsten oxide described above occurs in region 10B, causing the electrical resistance of the sensitive film 3 to decrease and short-circuiting the first sensor electrode 7 and the second sensor electrode 8. Therefore, by measuring the electrical resistance with the control unit 4, the location where the electrical resistance has decreased due to the reaction of the sensitive film 3 with hydrogen can be identified. Therefore, by using the hydrogen sensor disclosed herein, it is possible to identify the location of a hydrogen leak.

[0026] In this way, by using the hydrogen sensor according to the present disclosure, hydrogen leaks can be detected over a wide area at low cost, and the location of the hydrogen leak can be identified.

[0027] The hydrogen sensor of the present disclosure has three preferred embodiments, each of which will be described below.

[0028] I. First embodiment A first embodiment of a hydrogen sensor in the present disclosure is the above-mentioned hydrogen sensor, in which one of the first bus electrodes and one of the second bus electrodes are arranged in a line that can be drawn in one stroke, and one end of the first bus electrode and one end of the second bus electrode are connected to the control unit.

[0029] FIG. 3 is a schematic plan view showing an example of a hydrogen sensor according to this embodiment. As shown in FIG. 3, the hydrogen sensor 1 includes a substrate 2, a sensitive membrane 3 disposed on a first surface of the substrate 2 and containing a catalyst that dissociates hydrogen molecules and tungsten oxide, a control unit 4 that detects changes in electrical resistance, a first bus electrode 5 and a second bus electrode 6 disposed on the first surface of the substrate 2 and connected to the control unit 4, a plurality of first sensor electrodes 7 disposed on the first surface of the substrate 2 in contact with the sensitive membrane 3 and connected to the first bus electrode 5, and a plurality of second sensor electrodes 8 disposed on the first surface of the substrate 2 in contact with the sensitive membrane 3 and connected to the second bus electrode 6. The first sensor electrodes 7 and the second sensor electrodes 8 are alternately arranged at intervals that allow changes in the electrical resistance of the sensitive membrane 3 to be detected. In FIG. 3, the first sensor electrode 7 and the second sensor electrode 8 are a pair of comb-shaped electrodes. The first bus electrode 5 and the second bus electrode 6 are arranged in a line that can be drawn in one stroke. 3, the first bus electrode 5 and the second bus electrode 6 are arranged in a meandering line. One end of the first bus electrode 5 and one end of the second bus electrode 6 are connected to the control unit 4.

[0030] As described above, the hydrogen sensor shown in Figure 3 can detect hydrogen gas by detecting changes in electrical resistance using the control unit. The hydrogen sensor shown in Figure 3 also has one control unit, and by measuring electrical resistance using this single control unit, it is possible to identify the position where the sensitive film has reacted with hydrogen and the electrical resistance has decreased.

[0031] Fig. 4 is a schematic plan view showing another example of the hydrogen sensor of this embodiment. The hydrogen sensor 1 shown in Fig. 4 is similar to the hydrogen sensor 1 shown in Fig. 3 above, except that the control unit includes a first control unit 4a connected to one end of the first bus electrode 5 and one end of the second bus electrode 6, and a second control unit 4b connected to the other end of the first bus electrode 5 and the other end of the second bus electrode 6.

[0032] As described above, the hydrogen sensor shown in Fig. 4 can detect hydrogen gas by detecting changes in electrical resistance using the control unit. The hydrogen sensor shown in Fig. 4 has two control units, a first control unit 4a and a second control unit 4b, and the position where the electrical resistance has decreased due to the reaction of the sensitive membrane 3 with hydrogen can be identified based on the difference between the electrical resistance measured by the first control unit 4a and the electrical resistance measured by the second control unit 4b.

[0033] As described above, by using the hydrogen sensor of this embodiment, hydrogen leaks can be detected over a wide area at low cost, and the location of the hydrogen leak can be identified.

[0034] The hydrogen sensor of this embodiment will be described below in detail for each of its components.

[0035] 1. First sensor electrode and second sensor electrode In this embodiment, a plurality of first sensor electrodes and a plurality of second sensor electrodes are arranged on the first surface of the substrate in contact with the sensitive film, and are alternately arranged at intervals that allow detection of changes in the electrical resistance of the sensitive film. The first sensor electrodes are connected to a first bus electrode, the second sensor electrodes are connected to a second bus electrode, and the first sensor electrodes and the second sensor electrodes are not connected.

[0036] In this specification, the "interval at which a change in the electrical resistance of the sensitive film can be detected" refers to the interval at which the first sensor electrode and the second sensor electrode can be short-circuited when the above-mentioned reduction reaction of tungsten oxide occurs and the electrical resistance of the sensitive film decreases.

[0037] The plurality of first sensor electrodes and the plurality of second sensor electrodes may be arranged alternately at intervals that allow detection of changes in the electrical resistance of the sensitive film, and may be, for example, a pair of comb-shaped electrodes.

[0038] The distance between the first sensor electrode and the second sensor electrode may be any distance that allows detection of changes in the electrical resistance of the sensitive membrane. The distance may be, for example, 100 μm or more, or 500 μm or more. The distance may be, for example, 10 mm or less, or 5 mm or less. That is, the distance may be, for example, 100 μm or more and 10 mm or less, or 500 μm or more and 5 mm or less.

[0039] The distance between the first and second sensor electrodes is the distance from the edge of the adjacent first sensor electrode to the edge of the adjacent second sensor electrode. For example, in Figure 3, the distance between the first and second sensor electrodes is indicated by d1.

[0040] The width of the first sensor electrode and the width of the second sensor electrode may be any width that can detect changes in the electrical resistance of the sensitive membrane. The width may be, for example, 100 μm or more, or 500 μm or more. The width may be, for example, 10 mm or less, or 5 mm or less. That is, the width may be, for example, 100 μm or more and 10 mm or less, or 500 μm or more and 5 mm or less. For example, in FIG. 3, the width of the first sensor electrode is indicated by b1, and the width of the second sensor electrode is indicated by b2.

[0041] The length of the first sensor electrode and the second sensor electrode may be any length that allows detection of changes in the electrical resistance of the sensitive membrane. The length may be, for example, 10 mm or more, or 50 mm or more. The length may be, for example, 500 mm or less, or 100 mm or less. That is, the length may be, for example, 10 mm or more and 500 mm or less, or 50 mm or more and 100 mm or less. For example, in FIG. 3, the length of the first sensor electrode is indicated by a1, and the length of the second sensor electrode is indicated by a2.

[0042] The overlap length between the first sensor electrode and the second sensor electrode may be any length that allows detection of changes in the electrical resistance of the sensitive membrane. The overlap length may be, for example, 9 mm or more, or 45 mm or more. The overlap length may be, for example, 450 mm or less, or 90 mm or less. That is, the overlap length may be, for example, 9 mm or more and 450 mm or less, or 45 mm or more and 90 mm or less. For example, in FIG. 3, the overlap length between the first sensor electrode and the second sensor electrode is indicated by c.

[0043] The number of first sensor electrodes and the number of second sensor electrodes are set appropriately depending on the size of the hydrogen sensor, the arrangement of the first bus electrodes, the arrangement of the second bus electrodes, and the like.

[0044] The shapes of the first sensor electrode and the second sensor electrode are not particularly limited, and may be, for example, linear, polygonal, or curved. For example, in Fig. 3, the first sensor electrode 7 and the second sensor electrode 8 are linear. Also, for example, in Fig. 5, the first sensor electrode 7 is linear and polygonal, and the second sensor electrode 8 is linear.

[0045] Examples of conductive materials used for the first and second sensor electrodes include carbon and metal materials. Carbon is particularly preferred. Carbon is inert to hydrogen gas and inexpensive. As will be described later, when the sensitive film, the first sensor electrode, and the second sensor electrode are arranged in this order on the first surface of the substrate, the conductive material used for the first and second sensor electrodes is preferably inert to hydrogen gas. On the other hand, when the first and second sensor electrodes and the sensitive film are arranged in this order on the first surface of the substrate, the conductive material used for the first and second sensor electrodes may be active or inactive to hydrogen gas because it is not exposed to hydrogen gas.

[0046] The thickness of the first sensor electrode and the second sensor electrode is not particularly limited as long as they can function as electrodes, and is, for example, 0.1 μm or more and 2 μm or less.

[0047] The method for forming the first sensor electrode and the second sensor electrode is not particularly limited, and examples thereof include a method of forming a conductive film and patterning it, a mask vapor deposition method, and a printing method. Examples of the method for forming the conductive film include a vacuum vapor deposition method, a sputtering method, an ion plating method, and a plating method. Examples of the patterning method include an etching method and a lift-off method.

[0048] 2. First bus electrode and second bus electrode In this embodiment, the first bus electrode and the second bus electrode are disposed on the first surface of the substrate and connected to the control unit. The hydrogen sensor of this embodiment has one first bus electrode and one second bus electrode. The first bus electrode and the second bus electrode are disposed in a line that can be drawn in one stroke.

[0049] In this specification, the term "linear shape that can be drawn in one stroke" means that the shape is made up of one continuous line, with no overlapping portions.

[0050] The linear shape that can be drawn in one stroke is not particularly limited as long as it allows the first bus electrode, second bus electrode, first sensor electrode, and second sensor electrode to be arranged over the entire first surface of the substrate, and examples include a meandering linear shape as shown in Figures 3 and 4 and a spiral shape as shown in Figure 5. Of these, it is preferable that the first bus electrode and second bus electrode are arranged in a meandering linear shape. In this case, the first bus electrode and second bus electrode can be formed by a roll-to-roll process, allowing for efficient mass production of hydrogen sensors.

[0051] The first bus electrode and the second bus electrode are arranged so that the position where the electrical resistance of the sensitive film changes can be identified. Specifically, the first sensor electrodes connected to the first bus electrode and the second sensor electrodes connected to the second bus electrode are arranged alternately, so that the first bus electrodes and the second bus electrodes are arranged along each other.

[0052] The width of the first bus electrode and the width of the second bus electrode may be any width that allows them to function as electrodes. The width may be, for example, 1 mm or more, and may be 5 mm or more. The width may be, for example, 50 mm or less, and may be 10 mm or less. That is, the width may be, for example, 1 mm or more and 50 mm or less, and may be 5 mm or more and 10 mm or less. For example, in FIG. 3, the width of the first bus electrode is indicated by e1, and the width of the second bus electrode is indicated by e2.

[0053] The distance between the first bus electrode and the second bus electrode that face each other across the first sensor electrode and the second sensor electrode may be any distance that allows the first sensor electrode and the second sensor electrode to be arranged. The distance may be, for example, 11 mm or more, or 55 mm or more. The distance may also be, for example, 550 mm or less, or 110 mm or less. That is, the distance may be, for example, 11 mm or more and 550 mm or less, or 55 mm or more and 110 mm or less. For example, in FIG. 3, the distance between the first bus electrode and the second bus electrode that face each other across the first sensor electrode and the second sensor electrode is indicated by f.

[0054] The distance between the first and second bus electrodes facing each other without the first and second sensor electrodes sandwiched therebetween may be any distance that prevents detection of changes in the electrical resistance of the sensitive film. The distance may be, for example, 10 mm or more, or 50 mm or more. The distance may also be, for example, 100 mm or less, or 70 mm or less. That is, the distance may be, for example, 10 mm or more to 100 mm or less, or 50 mm or more to 70 mm or less. If the distance is too small, when the reduction reaction of tungsten oxide occurs and the electrical resistance of the sensitive film decreases, the first and second bus electrodes facing each other without the first and second sensor electrodes sandwiched therebetween may easily become conductive, making it difficult to identify the hydrogen leak location. For example, in FIG. 3, the distance between the first and second bus electrodes facing each other without the first and second sensor electrodes sandwiched therebetween is indicated by g.

[0055] The distance between adjacent first bus electrodes and the distance between adjacent second bus electrodes may be any distance that prevents detection of changes in the electrical resistance of the sensitive film. The distance may be, for example, 10 mm or more, or 50 mm or more. The distance may also be, for example, 100 mm or less, or 70 mm or less. That is, the distance may be, for example, 10 mm or more and 100 mm or less, or 50 mm or more and 70 mm or less. If the distance is too small, when the reduction reaction of tungsten oxide occurs and the electrical resistance of the sensitive film decreases, electrical conduction between adjacent first bus electrodes or adjacent second bus electrodes may become more likely, making it difficult to identify the hydrogen leak location. For example, in FIG. 3, the distance between adjacent first bus electrodes is indicated by h1, and the distance between adjacent second bus electrodes is indicated by h2.

[0056] The first bus electrode and the second bus electrode form a pair of electrodes, and the number of first bus electrodes and the number of second bus electrodes are typically one. However, as long as the first bus electrode and the second bus electrode form a pair of electrodes, the number of first bus electrodes and the number of second bus electrodes may be two. For example, in FIG. 6, hydrogen sensor 1 has two first bus electrodes 5a, 5b and two second bus electrodes 6a, 6b, and first bus electrode 5a and second bus electrode 6a form a pair of electrodes, and first bus electrode 5b and second bus electrode 6b form a pair of electrodes.

[0057] The conductive material used for the first bus electrode and the second bus electrode is the same as the conductive material used for the first sensor electrode and the second sensor electrode described above.

[0058] The thickness of the first bus electrode and the thickness of the second bus electrode are similar to the thickness of the first sensor electrode and the thickness of the second sensor electrode described above.

[0059] The method of forming the first bus electrode and the method of forming the second bus electrode are the same as the method of forming the first sensor electrode and the method of forming the second sensor electrode described above.

[0060] 3. Sensitive membrane The sensitive film in this embodiment contains a catalyst that dissociates hydrogen molecules and tungsten oxide.

[0061] The sensitive film may be a single layer containing a catalyst and tungsten oxide, or may have, in order from the substrate side, a tungsten oxide layer containing tungsten oxide and a catalyst layer containing a catalyst.

[0062] When the sensitive film has a tungsten oxide layer and a catalyst layer, the catalyst layer may be a continuous film or a discontinuous film.

[0063] The catalyst is not particularly limited as long as it can dissociate hydrogen molecules into hydrogen ions (protons), and examples thereof include noble metals such as palladium, platinum, iridium, etc. The catalyst may be used alone or in combination of two or more.

[0064] Tungsten oxide is tungsten trioxide (WO3).

[0065] The position of the sensitive film is not particularly limited as long as it is disposed in contact with the first sensor electrode and the second sensor electrode. For example, the first sensor electrode, the second sensor electrode, and the sensitive film may be disposed in this order on the first surface of the substrate, or the sensitive film, the first sensor electrode, and the second sensor electrode may be disposed in this order on the first surface of the substrate.

[0066] When the sensitive film is a single layer containing a catalyst and tungsten oxide, the thickness of the sensitive film is not particularly limited as long as it is thick enough to detect changes in the electrical resistance of the sensitive film, and is, for example, 100 nm or more and 3000 nm or less.

[0067] On the other hand, when the sensitive film has a tungsten oxide layer and a catalyst layer, the thickness of the tungsten oxide layer is not particularly limited as long as it is thick enough to detect changes in the electrical resistance of the tungsten oxide layer, and is, for example, 100 nm to 3000 nm, and the thickness of the catalyst layer is, for example, 1 nm to 10 nm.

[0068] When the sensitive film is a single layer containing a catalyst and tungsten oxide, the sensitive film can be formed by, for example, a sol-gel method. For examples of methods for forming sensitive films using the sol-gel method, see Japanese Patent Nos. 5152797 and 5540248.

[0069] On the other hand, when the sensitive film has a tungsten oxide layer and a catalyst layer, the method for forming the tungsten oxide layer is not particularly limited, and examples thereof include vacuum deposition, sputtering, and ion plating. The method for forming the catalyst layer is also not particularly limited, and examples thereof include vacuum deposition, sputtering, and ion plating.

[0070] 4. Control Unit The control unit in this embodiment is a component that detects changes in electrical resistance. The control unit is connected to the first bus electrode and the second bus electrode.

[0071] The control unit may be any device capable of detecting changes in electrical resistance, such as a device having an IC chip that detects changes in electrical resistance. The IC chip may be an open-short type IC chip. The open-short type IC chip detects changes in electrical resistance by setting a flag to "1" when inter-terminal resistance falls below a set value and to "0" when it exceeds another set value. Alternatively, a capacitive type IC chip may be used. A capacitive type IC chip typically detects changes in impedance when the antenna is detuned by contact with water droplets or the like. In the present disclosure, when a capacitive type IC chip is used, the above-mentioned sensitive film is separately placed in contact with the antenna of the IC tag (described later) to detect the changes in impedance. Among these, an open-short type IC chip is preferred. An example of an open-short type IC chip is the UCODE G2iM+ from NXP.

[0072] Specifically, an IC tag having the above-mentioned IC chip and antenna is used as the control unit. Note that IC tags are also called RF tags, RFID tags, electronic tags, wireless tags, etc. Any IC tag having the above-mentioned IC chip and antenna can be used, and a general IC tag can be used. In the case of an IC tag, hydrogen gas can be detected using RFID.

[0073] There are two types of IC tags: active, which have a built-in power source (battery), and passive, which do not. Of these, passive tags are preferred because they do not have their own power source (battery) but instead operate by receiving externally supplied radio waves via an antenna.

[0074] An example of the operating principle of the hydrogen sensor of the present disclosure when the control unit is an IC tag will be described. As described above, in an atmosphere without hydrogen, the sensitive film has high electrical resistance and is insulating. At this time, the first and second sensor electrodes are insulated and non-conductive. Therefore, even when power is supplied to the IC tag from an external device, no current flows through the sensitive film to the first and second sensor electrodes. On the other hand, in an atmosphere with hydrogen, the above-mentioned reduction reaction of tungsten oxide occurs, causing the sensitive film to have a lower electrical resistance and become conductive. At this time, the first and second sensor electrodes are short-circuited and become conductive. Therefore, when power is supplied to the IC tag from an external device, current flows through the sensitive film to the first and second sensor electrodes. The IC chip measures the electrical resistance value, detects information from the electrical resistance value, and transmits a signal corresponding to that information to the external device. Based on the information, the external device detects a hydrogen leak and identifies the location of the hydrogen leak.

[0075] There is at least one control unit. There may be one control unit, or there may be two, a first control unit and a second control unit. When there is one control unit, one end of the first bus electrode and one end of the second bus electrode are connected to the one control unit. When there are two control units, a first control unit and a second control unit, one end of the first bus electrode and one end of the second bus electrode are connected to the first control unit, and the other end of the first bus electrode and the other end of the second bus electrode are connected to the second control unit.

[0076] In particular, it is preferable that the control unit has two units: a first control unit and a second control unit. As described above, when control units are connected to both ends of the first bus electrode and both ends of the second bus electrode, the difference between the electrical resistance measured by the first control unit and the electrical resistance measured by the second control unit can be used to identify the position where the sensitive film reacts with hydrogen and the electrical resistance drops. This makes it possible to suppress an increase in electrical resistance due to the length of the first bus electrode and the length of the second bus electrode, and reduce the electrical load on the control unit. This can further increase reliability and improve the accuracy of the hydrogen sensor.

[0077] 5. Substrate The substrate in this embodiment is an insulating member that supports the sensitive film, the first sensor electrode, the second sensor electrode, the first bus electrode, and the second bus electrode.

[0078] The substrate is not particularly limited as long as it has insulating properties, and examples thereof include a glass substrate, a resin substrate, a ceramic substrate, and a silicon substrate having an insulating film on its surface.

[0079] The thickness of the substrate is not particularly limited, and is, for example, 10 μm or more and 2 mm or less.

[0080] 6. Other configurations In this embodiment, the sensitive film, first sensor electrode, second sensor electrode, first bus electrode, and second bus electrode may be arranged on a first surface of the substrate. The sensitive film, first sensor electrode, second sensor electrode, first bus electrode, and second bus electrode may be arranged on only one surface of the substrate, or the sensitive film, first sensor electrode, second sensor electrode, first bus electrode, and second bus electrode may be arranged on each of both surfaces of the substrate.

[0081] The hydrogen sensor of this embodiment can be made larger in area by appropriately designing the arrangement of the first bus electrode and the second bus electrode, etc. The size of the hydrogen sensor of this embodiment is not particularly limited, and is, for example, 0.3 m or more and 2 m or less in width and 0.3 m or more and 10 m or less in length.

[0082] II. Second embodiment A first embodiment of the hydrogen sensor in the present disclosure is the above-mentioned hydrogen sensor, in which the plurality of first bus electrodes and the plurality of second bus electrodes are connected to a control unit via a flexible printed circuit board.

[0083] FIG. 7 is a schematic plan view showing an example of a hydrogen sensor according to this embodiment. As shown in FIG. 7, the hydrogen sensor 1 includes a substrate 2, a sensitive membrane 3 disposed on a first surface of the substrate 2 and containing a catalyst that dissociates hydrogen gas into hydrogen atoms and tungsten oxide, a control unit 4 that detects changes in electrical resistance, a plurality of first bus electrodes 5 and a plurality of second bus electrodes 6 disposed on the first surface of the substrate 2 and connected to the control unit 4, a plurality of first sensor electrodes 7 disposed on the first surface of the substrate 2 in contact with the sensitive membrane 3 and connected to the first bus electrodes 5, and a plurality of second sensor electrodes 8 disposed on the first surface of the substrate 2 in contact with the sensitive membrane 3 and connected to the second bus electrodes 6. The first sensor electrodes 7 and the second sensor electrodes 8 are alternately arranged at intervals that allow changes in the electrical resistance of the sensitive membrane 3 to be detected. In FIG. 7, the first sensor electrodes 7 and the second sensor electrodes 8 are pairs of comb-shaped electrodes. The plurality of first bus electrodes 5 and the plurality of second bus electrodes 6 are connected to the control unit 4 via a flexible printed circuit board 9.

[0084] As described above, the hydrogen sensor shown in Figure 7 can detect hydrogen gas by detecting changes in electrical resistance using the control unit. Furthermore, the hydrogen sensor shown in Figure 7 has one control unit, and by measuring the electrical resistance using that one control unit, it is possible to identify the position where the sensitive film has reacted with hydrogen and the electrical resistance has decreased.

[0085] Fig. 8 is a schematic plan view showing another example of the hydrogen sensor of this embodiment. The hydrogen sensor 1 shown in Fig. 8 is similar to the hydrogen sensor 1 shown in Fig. 7 above, except that the control unit includes a first control unit 4a connected to one end of the first bus electrode 5 and one end of the second bus electrode 6, and a second control unit 4b connected to the other end of the first bus electrode 5 and the other end of the second bus electrode 6.

[0086] As described above, the hydrogen sensor shown in Fig. 8 can detect hydrogen gas by detecting changes in electrical resistance using the control unit. The hydrogen sensor shown in Fig. 8 has two control units, a first control unit 4a and a second control unit 4b, and the position where the electrical resistance has decreased due to the reaction of the sensitive film 3 with hydrogen can be identified based on the difference between the electrical resistance measured by the first control unit 4a and the electrical resistance measured by the second control unit 4b.

[0087] As described above, by using the hydrogen sensor of this embodiment, hydrogen leaks can be detected over a wide area at low cost, and the location of the hydrogen leak can be identified. Furthermore, in this embodiment, the lengths of the first and second bus electrodes can be shortened compared to the first embodiment, thereby suppressing an increase in electrical resistance due to the lengths of the first and second bus electrodes. This improves the accuracy of the hydrogen sensor.

[0088] Furthermore, in this embodiment, the first bus electrode and the second bus electrode can be arranged in a straight line, which reduces the risk of disconnection.

[0089] The hydrogen sensor of this embodiment will be described below in detail for each of its components.

[0090] 1. First sensor electrode and second sensor electrode In this embodiment, a plurality of first sensor electrodes and a plurality of second sensor electrodes are arranged on the first surface of the substrate in contact with the sensitive film, and are alternately arranged at intervals that allow detection of changes in the electrical resistance of the sensitive film. The first sensor electrodes are connected to a first bus electrode, the second sensor electrodes are connected to a second bus electrode, and the first sensor electrodes and the second sensor electrodes are not connected.

[0091] The distance between the first sensor electrode and the second sensor electrode may be any distance that allows detection of changes in the electrical resistance of the sensitive membrane. The distance may be, for example, 100 μm or more, or 500 μm or more. The distance may be, for example, 10 mm or less, or 5 mm or less. That is, the distance may be, for example, 100 μm or more and 10 mm or less, or 500 μm or more and 5 mm or less.

[0092] The distance between the first and second sensor electrodes is the distance from the edge of the adjacent first sensor electrode to the edge of the adjacent second sensor electrode. For example, in Figure 7, the distance between the first and second sensor electrodes is indicated by d1.

[0093] The width of the first sensor electrode and the width of the second sensor electrode may be any width that can detect changes in the electrical resistance of the sensitive membrane. The width may be, for example, 100 μm or more, or 500 μm or more. The width may be, for example, 10 mm or less, or 5 mm or less. That is, the width may be, for example, 100 μm or more and 10 mm or less, or 500 μm or more and 5 mm or less. For example, in FIG. 7, the width of the first sensor electrode is indicated by b1, and the width of the second sensor electrode is indicated by b2.

[0094] The length of the first sensor electrode and the second sensor electrode may be any length that allows detection of changes in the electrical resistance of the sensitive membrane. The length may be, for example, 10 mm or more, or 50 mm or more. The length may be, for example, 500 mm or less, or 100 mm or less. That is, the length may be, for example, 10 mm or more and 500 mm or less, or 50 mm or more and 100 mm or less. For example, in FIG. 7, the length of the first sensor electrode is indicated by a1, and the length of the second sensor electrode is indicated by a2.

[0095] The overlap length between the first sensor electrode and the second sensor electrode may be any length that allows detection of changes in the electrical resistance of the sensitive membrane. The overlap length may be, for example, 9 mm or more, or 45 mm or more. The overlap length may be, for example, 450 mm or less, or 90 mm or less. That is, the overlap length may be, for example, 9 mm or more and 450 mm or less, or 45 mm or more and 90 mm or less. For example, in FIG. 7, the overlap length between the first sensor electrode and the second sensor electrode is indicated by c.

[0096] The number of first sensor electrodes and the number of second sensor electrodes are set appropriately depending on the size of the hydrogen sensor, the arrangement of the first bus electrodes, the arrangement of the second bus electrodes, and the like.

[0097] The shapes of the first sensor electrode and the second sensor electrode are not particularly limited, and may be, for example, linear, polygonal, or curved.

[0098] The conductive material used for the first sensor electrode and the second sensor electrode, the thickness of the first sensor electrode and the second sensor electrode, and the method of forming the first sensor electrode and the second sensor electrode are the same as those of the first sensor electrode and the second sensor electrode in the first embodiment described above.

[0099] 2. First bus electrode and second bus electrode In this embodiment, the first bus electrode and the second bus electrode are disposed on the first surface of the substrate and connected to the controller. The hydrogen sensor of this embodiment has a plurality of first bus electrodes and a plurality of second bus electrodes.

[0100] The first bus electrode and the second bus electrode are a pair of electrodes and are arranged alternately.

[0101] The width of the first bus electrode and the width of the second bus electrode may be any width that allows them to function as electrodes. The width may be, for example, 1 mm or more, and may be 5 mm or more. The width may be, for example, 50 mm or less, and may be 10 mm or less. That is, the width may be, for example, 1 mm or more and 50 mm or less, and may be 5 mm or more and 10 mm or less. For example, in FIG. 7, the width of the first bus electrode is indicated by e1, and the width of the second bus electrode is indicated by e2.

[0102] The distance between the first bus electrode and the second bus electrode may be any distance that allows the first sensor electrode and the second sensor electrode to be arranged. The distance may be, for example, 11 mm or more, or 55 mm or more. The distance may be, for example, 550 mm or less, or 110 mm or less. That is, the distance may be, for example, 11 mm or more and 550 mm or less, or 55 mm or more and 110 mm or less. For example, in FIG. 7, the distance between the first bus electrode and the second bus electrode is indicated by f.

[0103] The number of first bus electrodes and the number of second bus electrodes are plural. The first bus electrodes and the second bus electrodes only need to form a pair of electrodes, and the number of first bus electrodes and the number of second bus electrodes may be the same or different. For example, in Figure 7, there are four first bus electrodes 5 and five second bus electrodes 6, so the number of first bus electrodes and the number of second bus electrodes are different.

[0104] The conductive material used for the first bus electrode and the second bus electrode is the same as the conductive material used for the first sensor electrode and the second sensor electrode described above.

[0105] The thickness of the first bus electrode and the thickness of the second bus electrode are similar to the thickness of the first sensor electrode and the thickness of the second sensor electrode described above.

[0106] The method of forming the first bus electrode and the method of forming the second bus electrode are the same as the method of forming the first sensor electrode and the method of forming the second sensor electrode described above.

[0107] 3. Sensitive membrane The sensitive film in this embodiment contains a catalyst that dissociates hydrogen gas into hydrogen atoms and tungsten oxide, and is the same as the sensitive film in the first embodiment.

[0108] 4. Control Unit The control unit in this embodiment is a component that detects changes in electrical resistance. The control unit is connected to the first bus electrode and the second bus electrode.

[0109] The control unit is the same as the control unit in the first embodiment.

[0110] There is at least one control unit. There may be one control unit, or there may be two, a first control unit and a second control unit. When there is one control unit, one end of the first bus electrode and one end of the second bus electrode are connected to the one control unit. When there are two control units, a first control unit and a second control unit, one end of the first bus electrode and one end of the second bus electrode are connected to the first control unit, and the other end of the first bus electrode and the other end of the second bus electrode are connected to the second control unit.

[0111] 5. Flexible Printed Circuit Boards In this embodiment, the plurality of first bus electrodes and the plurality of second bus electrodes are connected to the control unit via a flexible printed circuit board (FPC), which may be a general FPC.

[0112] 6. Substrate The substrate in this embodiment is an insulating member that supports the sensitive membrane, the first sensor electrode, the second sensor electrode, the first bus electrode, and the second bus electrode. The substrate is the same as the substrate in the first embodiment.

[0113] III. Third embodiment A third embodiment of the hydrogen sensor in the present disclosure is the above-mentioned hydrogen sensor, in which a plurality of the first bus electrodes are arranged along a first direction, a plurality of the second bus electrodes are arranged along a second direction perpendicular to the first direction, the control unit has a third control unit connected to one end of the plurality of first bus electrodes and a fourth control unit connected to one end of the plurality of second bus electrodes, and in the region where the first bus electrodes and the second bus electrodes intersect, an insulating film is arranged between the first bus electrodes and the second bus electrodes.

[0114] FIG. 9 is a schematic plan view showing an example of a hydrogen sensor according to this embodiment. As shown in FIG. 9, the hydrogen sensor 1 includes a substrate 2, a sensitive membrane 3 disposed on a first surface of the substrate 2 and containing a catalyst that dissociates hydrogen molecules and tungsten oxide, a third control unit 4c and a fourth control unit 4d that detect changes in electrical resistance, a plurality of first bus electrodes 5 disposed on the first surface of the substrate 2 and connected to the third control unit 4c, and a plurality of second bus electrodes 6 connected to the fourth control unit 4d, a plurality of first sensor electrodes 7 disposed on the first surface of the substrate 2 in contact with the sensitive membrane 3 and connected to the first bus electrodes 5, and a plurality of second sensor electrodes 8 disposed on the first surface of the substrate 2 in contact with the sensitive membrane 3 and connected to the second bus electrodes 6. The first sensor electrodes 7 and the second sensor electrodes 8 are alternately arranged at intervals that allow changes in the electrical resistance of the sensitive membrane 3 to be detected. In FIG. 9, the first sensor electrodes 7 and the second sensor electrodes 8 are pairs of comb-shaped electrodes. The multiple first bus electrodes 5 are arranged linearly in a first direction D1, and the multiple second bus electrodes 6 are arranged linearly in a second direction D2 perpendicular to the first direction D1. The control unit has a third control unit 4c connected to one ends of the multiple first bus electrodes 5 and a fourth control unit 4d connected to one ends of the multiple second bus electrodes 6. In the region where the first bus electrodes 5 and the second bus electrodes 6 intersect, an insulating film 11 is arranged between the first bus electrodes 5 and the second bus electrodes 6.

[0115] As described above, the hydrogen sensor shown in Fig. 9 can detect hydrogen gas by detecting changes in electrical resistance using the control unit. Furthermore, in the hydrogen sensor shown in Fig. 9, the third control unit and the fourth control unit measure the electrical resistance, thereby identifying the intersections of the first bus electrode and the second bus electrode where the electrical resistance has decreased. Therefore, the intersections of the first bus electrode and the second bus electrode where the electrical resistance has decreased can be identified as the positions where the sensitive film has reacted with hydrogen and the electrical resistance has decreased.

[0116] As described above, by using the hydrogen sensor of this embodiment, hydrogen leaks can be detected over a wide area at low cost, and the location of the hydrogen leak can be identified.

[0117] In addition, in this embodiment, the first bus electrode and the second bus electrode do not need to be arranged in a linear pattern that can be drawn in one stroke, thereby reducing the risk of disconnection. Also, as shown in Fig. 9, the area of ​​the overlapping portion 10C of the first sensor electrode 7 and the second sensor electrode 8 can be made constant, thereby reducing signal variations and improving detection sensitivity.

[0118] The hydrogen sensor of this embodiment will be described below in detail for each of its components.

[0119] 1. First sensor electrode and second sensor electrode In this embodiment, a plurality of first sensor electrodes and a plurality of second sensor electrodes are arranged on the first surface of the substrate in contact with the sensitive film, and are alternately arranged at intervals that allow detection of changes in the electrical resistance of the sensitive film. The first sensor electrodes are connected to a first bus electrode, the second sensor electrodes are connected to a second bus electrode, and the first sensor electrodes and the second sensor electrodes are not connected.

[0120] The plurality of first sensor electrodes and the plurality of second sensor electrodes may be arranged alternately at intervals that allow detection of changes in the electrical resistance of the sensitive film, and may be, for example, a pair of comb-shaped electrodes.

[0121] The distance between the first sensor electrode and the second sensor electrode may be any distance that allows detection of changes in the electrical resistance of the sensitive membrane. The distance may be, for example, 100 μm or more, or 500 μm or more. The distance may be, for example, 10 mm or less, or 5 mm or less. That is, the distance may be, for example, 100 μm or more and 10 mm or less, or 500 μm or more and 5 mm or less.

[0122] The distance between the first and second sensor electrodes is the distance from the edge of the adjacent first sensor electrode to the edge of the adjacent second sensor electrode. For example, in Figure 9, the distance between the first and second sensor electrodes is indicated by d1.

[0123] The width of the first sensor electrode and the width of the second sensor electrode may be any width that can detect changes in the electrical resistance of the sensitive membrane. The width may be, for example, 100 μm or more, or 500 μm or more. The width may be, for example, 10 mm or less, or 5 mm or less. That is, the width may be, for example, 100 μm or more and 10 mm or less, or 500 μm or more and 5 mm or less. For example, in FIG. 9, the width of the first sensor electrode is indicated by b1, and the width of the second sensor electrode is indicated by b2.

[0124] The length of the first sensor electrode and the second sensor electrode may be any length that allows detection of changes in the electrical resistance of the sensitive membrane. The length may be, for example, 10 mm or more, or 50 mm or more. The length may be, for example, 500 mm or less, or 100 mm or less. That is, the length may be, for example, 10 mm or more and 500 mm or less, or 50 mm or more and 100 mm or less. For example, in FIG. 9, the length of the first sensor electrode is indicated by a1, and the length of the second sensor electrode is indicated by a2.

[0125] The overlap length between the first sensor electrode and the second sensor electrode may be any length that allows detection of changes in the electrical resistance of the sensitive membrane. The overlap length may be, for example, 9 mm or more, or 45 mm or more. The overlap length may be, for example, 450 mm or less, or 90 mm or less. That is, the overlap length may be, for example, 9 mm or more and 450 mm or less, or 45 mm or more and 90 mm or less. For example, in FIG. 9, the overlap length between the first sensor electrode and the second sensor electrode is indicated by c.

[0126] The number of first sensor electrodes and the number of second sensor electrodes are set appropriately depending on the size of the hydrogen sensor, the arrangement of the first bus electrodes, the arrangement of the second bus electrodes, and the like.

[0127] The shapes of the first sensor electrode and the second sensor electrode are not particularly limited, and may be, for example, linear, polygonal, or curved. The first sensor electrode and the second sensor electrode may also have a branched shape. For example, in FIG. 9, the first sensor electrode 7 has a linear shape, and the second sensor electrode 8 has a branched shape. For example, in FIG. 10, the first sensor electrode 7 has a linear shape, and the second sensor electrode 8 has a polygonal shape.

[0128] The conductive material used for the first sensor electrode and the second sensor electrode, the thickness of the first sensor electrode and the second sensor electrode, and the method of forming the first sensor electrode and the second sensor electrode are the same as those of the first sensor electrode and the second sensor electrode in the first embodiment described above.

[0129] 2. First bus electrode and second bus electrode In this embodiment, the first bus electrode and the second bus electrode are disposed on a first surface of the substrate and connected to a controller. The hydrogen sensor of this embodiment has a plurality of first bus electrodes and a plurality of second bus electrodes. The first bus electrodes are disposed along a first direction, and the second bus electrodes are disposed along a second direction perpendicular to the first direction.

[0130] The width of the first bus electrode and the width of the second bus electrode may be any width that allows them to function as electrodes. The width may be, for example, 1 mm or more, and may be 5 mm or more. The width may be, for example, 50 mm or less, and may be 10 mm or less. That is, the width may be, for example, 1 mm or more and 50 mm or less, and may be 5 mm or more and 10 mm or less. For example, in FIG. 9, the width of the first bus electrode is indicated by e1, and the width of the second bus electrode is indicated by e2.

[0131] The distance between adjacent first bus electrodes and the distance between adjacent second bus electrodes may be any distance that allows the placement of the first sensor electrodes and the second sensor electrodes. The distance may be, for example, 11 mm or more, or 55 mm or more. The distance may be, for example, 550 mm or less, or 110 mm or less. That is, the distance may be, for example, 11 mm or more and 550 mm or less, or 55 mm or more and 110 mm or less. For example, in FIG. 9, the distance between adjacent first bus electrodes is indicated by k1, and the distance between adjacent second bus electrodes is indicated by k2.

[0132] The number of the first bus electrodes and the number of the second bus electrodes are plural.

[0133] The conductive material used for the first bus electrode and the second bus electrode is the same as the conductive material used for the first sensor electrode and the second sensor electrode described above.

[0134] The thickness of the first bus electrode and the thickness of the second bus electrode are similar to the thickness of the first sensor electrode and the thickness of the second sensor electrode described above.

[0135] The method of forming the first bus electrode and the method of forming the second bus electrode are the same as the method of forming the first sensor electrode and the method of forming the second sensor electrode described above.

[0136] 3. Sensitive membrane The sensitive film in this embodiment contains a catalyst that dissociates hydrogen molecules and tungsten oxide, and is the same as the sensitive film in the first embodiment.

[0137] The position of the sensitive film is not particularly limited as long as it is disposed in contact with the first sensor electrode and the second sensor electrode. For example, the first sensor electrode, the second sensor electrode, and the sensitive film may be disposed in this order on the first surface of the substrate, the sensitive film, the first sensor electrode, and the second sensor electrode may be disposed in this order on the first surface of the substrate, the first sensor electrode, the sensitive film, and the second sensor electrode may be disposed in this order on the first surface of the substrate, or the second sensor electrode, the sensitive film, and the first sensor electrode may be disposed in this order on the first surface of the substrate.

[0138] 4. Control Unit The control unit in this embodiment is a component that detects changes in electrical resistance. The control unit is connected to the first bus electrode and the second bus electrode.

[0139] The control unit is the same as the control unit in the first embodiment.

[0140] The control unit may include a third control unit connected to one ends of the plurality of first bus electrodes and a fourth control unit connected to one ends of the plurality of second bus electrodes. The control unit may also include the third control unit, the fourth control unit, and a fifth control unit connected to the other ends of the plurality of first bus electrodes. The control unit may also include the third control unit, the fourth control unit, and a sixth control unit connected to the other ends of the plurality of second bus electrodes. The control unit may also include the third control unit, the fourth control unit, the fifth control unit, and the sixth control unit. For example, in FIG. 11 , the control unit includes a third control unit 4c connected to one ends of the plurality of first bus electrodes 5, a fourth control unit 4d connected to one ends of the plurality of second bus electrodes 6, and a fifth control unit 4e connected to the other ends of the plurality of first bus electrodes 5.

[0141] 5. Substrate The substrate in this embodiment is an insulating member that supports the sensitive membrane, the first sensor electrode, the second sensor electrode, the first bus electrode, and the second bus electrode. The substrate is the same as the substrate in the first embodiment.

[0142] 6. Insulating film The insulating film in this embodiment is disposed between the first bus electrode and the second bus electrode in the region where the first bus electrode and the second bus electrode intersect.

[0143] The material for the insulating film is not particularly limited as long as it is an insulating material, and examples thereof include inorganic oxides, inorganic nitrides, inorganic carbides, and resins.

[0144] The thickness of the insulating film is not particularly limited as long as it is thick enough to insulate the first bus electrode and the second bus electrode, and is, for example, 0.1 μm or more and 2 μm or less.

[0145] The method for forming the insulating film is not particularly limited, and examples thereof include a method of forming an insulating film and patterning it, a mask vapor deposition method, and a printing method. Examples of the method for forming the insulating film include a vacuum vapor deposition method, a sputtering method, an ion plating method, and a plating method. Examples of the patterning method include an etching method and a lift-off method.

[0146] B. Hydrogen Detection System The hydrogen detection system of the present disclosure uses the hydrogen sensor described above.

[0147] Figure 12 is a schematic diagram showing an example of a hydrogen detection system according to the present disclosure. In Figure 12, a hydrogen detection system 20 includes multiple hydrogen sensors 1, an RFID reader / writer 21, and multiple antennas 22 connected to the RFID reader / writer 21. The hydrogen sensors 1 are attached to an underground hydrogen pipeline 30. The RFID reader / writer 21 and antenna 22 are fixed and installed at any location near the ground.

[0148] Figure 13 is a schematic diagram showing another example of a hydrogen detection system according to the present disclosure. In Figure 12, a hydrogen detection system 20 includes multiple hydrogen sensors 1, an RFID reader / writer 21, and an antenna 22 connected to the RFID reader / writer 21. The hydrogen sensors 1 are attached to an underground hydrogen pipeline 30. The RFID reader / writer 21 and antenna 22 are installed on a mobile object 23 and are therefore mobile.

[0149] In such a hydrogen detection system, the IC chip that constitutes the control unit of the hydrogen sensor is driven in a non-contact manner, and changes in the electrical resistance of the sensitive film can be detected, thereby making it possible to detect hydrogen gas.

[0150] The hydrogen detection system of the present disclosure is not particularly limited as long as it is a system that uses a hydrogen sensor, but is preferably a system that uses RFID. Specifically, the hydrogen detection system of the present disclosure includes a hydrogen sensor, an RFID reader / writer, and an antenna connected to the RFID reader / writer.

[0151] The RFID reader / writer may be either fixed or mobile. When a fixed RFID reader / writer is used, continuous monitoring is possible. On the other hand, when a mobile RFID reader / writer is used, trace inspection can be performed, making trace inspection more advanced, smarter, and less manpower-intensive.

[0152] The hydrogen detection system of the present disclosure can be used not only in small devices such as fuel cells, but also in large facilities such as hydrogen production facilities, hydrogen pipelines, transport tankers, storage tanks, and hydrogen power generation facilities.

[0153] C. Hydrogen sensor sheet The hydrogen sensor sheet of the present disclosure is a roll-shaped hydrogen sensor sheet having a substrate, a sensitive membrane disposed on a first surface of the substrate and containing a catalyst that dissociates hydrogen molecules and tungsten oxide, a bus electrode disposed on the first surface of the substrate and arranged in a serpentine line, and a plurality of first sensor electrodes and a plurality of second sensor electrodes disposed on the first surface of the substrate in contact with the sensitive membrane and connected to the bus electrode, the first sensor electrodes and the second sensor electrodes being alternately arranged at intervals that allow changes in the electrical resistance of the sensitive membrane to be detected.

[0154] Fig. 14 is a schematic perspective view showing an example of a hydrogen sensor sheet according to the present disclosure, and Fig. 15 is a schematic plan view showing an example of a hydrogen sensor sheet according to the present disclosure. As shown in Fig. 14, hydrogen sensor sheet 40 is in a roll form. As shown in Fig. 15, hydrogen sensor sheet 40 includes substrate 2, sensitive membrane 3 disposed on a first surface of substrate 2 and containing a catalyst that dissociates hydrogen molecules and tungsten oxide, bus electrode 41 disposed on the first surface of substrate 2 and arranged in a serpentine shape, and multiple first sensor electrodes 7 and multiple second sensor electrodes 8 disposed on the first surface of substrate 2 in contact with sensitive membrane 3 and connected to bus electrode 41. The first sensor electrodes 7 and second sensor electrodes 8 are alternately arranged at intervals that allow changes in the electrical resistance of sensitive membrane 3 to be detected.

[0155] The hydrogen sensor sheet according to the present disclosure is used in the manufacture of the hydrogen sensor described above. The hydrogen sensor sheet according to the present disclosure can be manufactured by a roll-to-roll method, allowing for efficient mass production of hydrogen sensors.

[0156] The bus electrode, first sensor electrode, second sensor electrode, and sensitive membrane in the hydrogen sensor sheet of the present disclosure are the same as the first bus electrode, second bus electrode, first sensor electrode, second sensor electrode, and sensitive membrane in the first embodiment of the hydrogen sensor described above, except that the first bus electrode and second bus electrode are connected in the first embodiment of the hydrogen sensor described above.

[0157] When manufacturing the above-described hydrogen sensor using the hydrogen sensor sheet of the present disclosure, the hydrogen sensor sheet is cut to the desired length, and the bus electrode at the portion where the control unit is to be connected is cut off.The control unit is then placed.

[0158] The present disclosure is not limited to the above-described embodiments. The above-described embodiments are merely examples, and any configuration that is substantially identical to the technical idea described in the claims of the present disclosure and that provides similar effects is included within the technical scope of the present disclosure. [Example]

[0159] The present disclosure will be described in more detail below with reference to examples.

[0160] The hydrogen sensor shown in Figure 4 was fabricated. A first bus electrode, a second bus electrode, a first sensor electrode, and a second sensor electrode were printed on a 50-μm-thick polyethylene terephthalate (PET) film. The length a1 of the first sensor electrode and the length a2 of the second sensor electrode were 70 mm, the width b1 of the first sensor electrode and the width b2 of the second sensor electrode were 2 mm, the overlap length c of the first sensor electrode and the second sensor electrode was 50 mm, the spacing d1 between the first sensor electrode and the second sensor electrode was 2 mm, the width e1 of the first bus electrode and the width e2 of the second bus electrode were 10 mm, the spacing f between the first bus electrode and the second bus electrode facing each other with the first sensor electrode and the second sensor electrode in between was 90 mm, the spacing g between the first bus electrode and the second bus electrode facing each other without the first sensor electrode and the second sensor electrode in between was 10 mm, and the spacing h1 between adjacent first bus electrodes and the spacing h2 between adjacent second bus electrodes were 10 mm. The thickness of the first bus electrode, the second bus electrode, the first sensor electrode, and the second sensor electrode were each 0.2 μm. Next, a sensitive film was formed on the PET film by the sol-gel method so as to cover the first bus electrode, the second bus electrode, the first sensor electrode, and the second sensor electrode. Next, an IC tag was connected and mounted on the first bus electrode and the second bus electrode. This resulted in the production of a hydrogen sensor.

[0161] An RFID reader / writer was used to transmit readout radio waves to the hydrogen sensor, and it was confirmed that the reflected and transmitted radio waves could be detected. Furthermore, when the hydrogen sensor was exposed to hydrogen gas and radio waves were transmitted in the same manner as above, the signal level of the reflected and transmitted radio waves changed. This confirmed that hydrogen gas can be detected without the hydrogen sensor itself being equipped with a power source.

[0162] Furthermore, the resistance measured by the first control unit was R1, the resistance measured by the second control unit was R2, and the location of the leak from the first control unit was identified by multiplying the total length of the first or second bus electrode by a coefficient obtained by dividing R1 by the total resistance (R1 + R2). Although the resistance value changes depending on the hydrogen concentration, the above method made it possible to accurately identify the location of the leak regardless of the hydrogen concentration.

[0163] In the present disclosure, the following inventions are provided: [1] A substrate; a sensitive film disposed on a first surface of the substrate, the sensitive film including a catalyst that dissociates hydrogen molecules and tungsten oxide; a control unit that detects a change in electrical resistance; a first bus electrode and a second bus electrode disposed on a first surface of the substrate and connected to the control unit; a plurality of first sensor electrodes arranged on a first surface of the substrate in contact with the sensitive film and connected to the first bus electrode; a plurality of second sensor electrodes disposed on the first surface of the substrate in contact with the sensitive film and connected to the second bus electrode; A hydrogen sensor, wherein the first sensor electrode and the second sensor electrode are alternately arranged at an interval that allows detection of a change in the electrical resistance of the sensitive film. [2] one of the first bus electrodes and one of the second bus electrodes is arranged in a line that can be drawn in one stroke, The hydrogen sensor according to [1], wherein one end of the first bus electrode and one end of the second bus electrode are connected to the control unit. [3] The hydrogen sensor described in [2], wherein the control unit has a first control unit connected to one end of the first bus electrode and one end of the second bus electrode, and a second control unit connected to the other end of the first bus electrode and the other end of the second bus electrode. [4] The hydrogen sensor according to [2] or [3], wherein the first bus electrode and the second bus electrode are arranged in a serpentine line. [5] The hydrogen sensor according to [1], wherein the plurality of first bus electrodes and the plurality of second bus electrodes are connected to the control unit via a flexible printed circuit board. [6] A plurality of the first bus electrodes are arranged along a first direction, a plurality of the second bus electrodes are arranged along a second direction perpendicular to the first direction; the control unit includes a third control unit connected to one ends of the plurality of first bus electrodes and a fourth control unit connected to one ends of the plurality of second bus electrodes; The hydrogen sensor according to [1], wherein an insulating film is disposed between the first bus electrode and the second bus electrode in a region where the first bus electrode and the second bus electrode intersect. [7] A hydrogen detection system using the hydrogen sensor according to any one of [1] to [6]. [8] A roll-shaped hydrogen sensor sheet, A substrate; a sensitive film disposed on a first surface of the substrate, the sensitive film including a catalyst that dissociates hydrogen molecules and tungsten oxide; bus electrodes arranged on a first surface of the substrate and arranged in a meandering line; a plurality of first sensor electrodes and a plurality of second sensor electrodes that are arranged on a first surface of the substrate in contact with the sensitive film and connected to the bus electrode; The hydrogen sensor sheet, wherein the first sensor electrode and the second sensor electrode are alternately arranged at intervals that allow detection of changes in the electrical resistance of the sensitive film. [Explanation of symbols]

[0164] 1... Hydrogen sensor 2... Substrate 3... Sensitive membrane 4...Control section 4a ... First control section 4b ... Second control section 4c ... Third control section 4d … 4th control section 5... First bus electrode 6 ... Second bus electrode 7 ... First sensor electrode 8 ... Second sensor electrode 20... Hydrogen detection system 40... Hydrogen sensor sheet

Claims

1. A substrate; a sensitive film disposed on a first surface of the substrate, the sensitive film including a catalyst for dissociating hydrogen molecules and tungsten oxide; a control unit that detects a change in electrical resistance; a first bus electrode and a second bus electrode disposed on a first surface of the substrate and connected to the control unit; a plurality of first sensor electrodes arranged on a first surface of the substrate in contact with the sensitive film and connected to the first bus electrode; a plurality of second sensor electrodes disposed on the first surface of the substrate in contact with the sensitive film and connected to the second bus electrode; the first sensor electrodes and the second sensor electrodes are alternately arranged at intervals that allow detection of changes in the electrical resistance of the sensitive film; A hydrogen sensor wherein the control unit is an IC tag having an antenna and an IC chip that detects changes in electrical resistance.

2. one of the first bus electrodes and one of the second bus electrodes are arranged in a line that can be drawn in one stroke, 2. The hydrogen sensor according to claim 1, wherein one end of the first bus electrode and one end of the second bus electrode are connected to the control unit.

3. A substrate, a sensitive film disposed on a first surface of the substrate, the sensitive film including a catalyst for dissociating hydrogen molecules and tungsten oxide; a control unit that detects a change in electrical resistance; a first bus electrode and a second bus electrode disposed on a first surface of the substrate and connected to the control unit; a plurality of first sensor electrodes arranged on a first surface of the substrate in contact with the sensitive film and connected to the first bus electrode; a plurality of second sensor electrodes disposed on the first surface of the substrate in contact with the sensitive film and connected to the second bus electrode; the first sensor electrodes and the second sensor electrodes are alternately arranged at intervals that allow detection of changes in the electrical resistance of the sensitive film; A hydrogen sensor, wherein the plurality of first bus electrodes and the plurality of second bus electrodes are connected to the control unit via a flexible printed circuit board.

4. A hydrogen detection system using the hydrogen sensor according to any one of claims 1 to 3.

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