Hydrogen sensor, hydrogen detection system, and hydrogen sensor sheet

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 Art

[0002] In recent years, from the viewpoints of global environmental protection and prevention of depletion of fossil fuels, utilization of clean and recyclable energy has been desired. In particular, research for using hydrogen gas as an energy source has been actively conducted mainly centered around fuel cells. On the other hand, the explosion limit concentration of hydrogen gas is as wide as 4% to 75%, and for hydrogen gas to be popularized as an energy source, handling such as storage and transportation of hydrogen, and safety devices against hydrogen leakage are indispensable.

[0003] For example, adding odorants 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 occur. Therefore, safety measures alternative to adding odorants are required. Thus, in order to ensure safety, hydrogen sensors for detecting leakage of hydrogen gas have become extremely important.

[0004] Conventional hydrogen sensors mainly use the catalytic combustion method or the semiconductor method. In the hydrogen sensor using the catalytic combustion method, a catalytic metal such as platinum or palladium is heated by a heater, and hydrogen gas in contact with the catalyst is oxidized by oxygen in the air. The heat generated by this oxidation action of hydrogen gas is electrically detected as a change in the conductivity of the catalytic metal. Also, in the semiconductor type hydrogen sensor, a change in the electrical characteristics of the sensitive film, that is, a change in electrical resistance, due to adsorption of hydrogen gas to the sensitive film is detected. This semiconductor type hydrogen sensor is also used in a heated state like the catalytic combustion type. Thus, in conventional hydrogen sensors such as the catalytic combustion method and the semiconductor method, since heating is performed, there is a risk for hydrogen gas that requires explosion-proof measures.

[0005] In recent years, gasochromic hydrogen sensors have also attracted attention. A gasochromic hydrogen sensor includes a metal oxide such as tungsten trioxide whose color changes due to hydrogen adsorption, and a catalyst such as platinum that dissociates hydrogen gas into hydrogen atoms, and optically detects hydrogen gas. Since the electrical properties of a metal oxide such as tungsten trioxide also change due to hydrogen adsorption, a gasochromic hydrogen sensor can also electrically detect hydrogen gas. (See, for example, Patent Documents 1 and 2.)

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] Conventional hydrogen sensors such as the catalytic combustion method and the semiconductor method detect hydrogen gas at the installed location. Therefore, hydrogen gas can only be detected in a narrow range. Also, it is difficult to identify the location of hydrogen leakage.

[0008] The present disclosure has been made in view of the above circumstances, and the main object is to provide a hydrogen sensor that can detect hydrogen gas even in a wide range and can also identify the location of hydrogen leakage.

Means for Solving the Problems

[0009] One embodiment of the present disclosure provides a hydrogen sensor having a substrate, a sensing film disposed on a first surface of the substrate and containing a catalyst for dissociating hydrogen molecules and tungsten oxide, a control unit for detecting a change 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 in contact with the sensing film on the first surface of the substrate and connected to the first bus electrode, and a plurality of second sensor electrodes disposed in contact with the sensing film on the first surface of the substrate and connected to the second bus electrode, wherein the first sensor electrodes and the second sensor electrodes are alternately arranged at intervals capable of detecting a change in the electrical resistance of the sensing film.

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

[0011] Another embodiment of the present disclosure provides a sheet for a roll-shaped hydrogen sensor, having a substrate, a sensing film disposed on a first surface of the substrate and containing a catalyst for dissociating hydrogen molecules and tungsten oxide, a bus electrode disposed on the first surface of the substrate and arranged in a meandering line, and a plurality of first sensor electrodes and a plurality of second sensor electrodes disposed in contact with the sensing film on the first surface of the substrate and connected to the bus electrode, wherein the first sensor electrodes and the second sensor electrodes are alternately arranged at intervals capable of detecting a change in the electrical resistance of the sensing film.

Advantages of the Invention

[0012] The hydrogen sensor according to the present disclosure has the effect of being able to detect hydrogen gas even in a wide range and being able to identify the location of hydrogen leakage.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

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Figure 10

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Embodiments for Carrying Out the Invention

[0014] Hereinafter, 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 modes and is not construed as being limited to the description content of the embodiments exemplified below. In addition, for the purpose of making the description clearer, the drawings may schematically represent the width, thickness, shape, etc. of each member compared to the embodiments, but this is merely an example and does not limit the interpretation of the present disclosure. Also, in this specification and each figure, the same reference numerals may be given to the same elements as those described above with respect to the previously presented figures, and detailed descriptions may be omitted as appropriate.

[0015] In this specification, when expressing the mode of arranging one member on another member, if simply expressed as "on the surface side" or "on the surface", unless otherwise specified, it includes both the case of arranging another member directly above or below so as to be in contact with one member, and the case of arranging another member above or below one member with yet another member interposed therebetween.

[0016] Also, in this specification, terms such as "sheet", "film", and "plate" are not distinguished from each other based only on the difference in name. For example, "sheet" is used in the sense that it includes members that can also be called films or plates.

[0017] Hereinafter, the hydrogen sensor, hydrogen detection system, and sheet for hydrogen sensor in the present disclosure will be described in detail.

[0018] A. Hydrogen sensor The hydrogen sensor in the present disclosure includes a substrate, a sensitive film disposed on the first surface of the substrate and containing a catalyst for dissociating hydrogen molecules and tungsten oxide, a control unit for detecting a change 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 film 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 film and connected to the second bus electrode, wherein the first sensor electrodes and the second sensor electrodes are alternately arranged at intervals capable of detecting a change in the electrical resistance of the sensitive film.

[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 (WO 3 ) 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 dissociate and adsorb to generate hydrogen atoms. These hydrogen atoms reduce tungsten oxide (WO 3 ) to form a non-stoichiometric compound (H x WO 3 (0 < x < 1)). The non-stoichiometric compound (H x WO 3 ) is in a mixed valence state of W 5+ and W 6+ , so it has a low electrical resistance. Therefore, in an atmosphere where hydrogen is present, the above reduction reaction of tungsten oxide occurs, the electrical resistance of the sensitive film decreases, and it 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. Therefore, by detecting a change in electrical resistance by the control unit, hydrogen gas can be detected.

[0024] In conventional hydrogen sensors such as semiconductor type and catalytic combustion type, as described above, heating is required and hydrogen gas can be detected only in a narrow range. On the other hand, the reduction reaction of tungsten oxide described above does not require the supply of electricity. Therefore, the hydrogen sensor in the present disclosure can be made larger in area and can detect hydrogen gas in a relatively wide range at low cost. Therefore, by using the hydrogen sensor in the present disclosure, it is possible to detect hydrogen gas leakage 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] Also, the electrical resistance of a conductor is proportional to the length of the conductor. Therefore, as illustrated in FIG. 2, when the reduction reaction of tungsten oxide occurs in region 10A and the electrical resistance of the sensing film 3 decreases, causing the first sensor electrode 7 and the second sensor electrode 8 to short-circuit, and when the reduction reaction of tungsten oxide occurs in region 10B and the electrical resistance of the sensing film 3 decreases, causing the first sensor electrode 7 and the second sensor electrode 8 to short-circuit, the values of the electrical resistance measured by the control unit 4 are different. Therefore, by measuring the electrical resistance by the control unit 4, the position where the sensing film 3 reacts with hydrogen and the electrical resistance decreases can be specified. Therefore, by using the hydrogen sensor in the present disclosure, the hydrogen leakage location can be specified.

[0026] Thus, by using the hydrogen sensor in the present disclosure, hydrogen leakage can be detected at low cost over a wide range, and furthermore, the hydrogen leakage location can be specified.

[0027] The hydrogen sensor in the present disclosure has three preferred embodiments. Each embodiment will be described below.

[0028] I. First Embodiment The first embodiment of the hydrogen sensor in the present disclosure is the above-described hydrogen sensor, in which one of the first bus electrodes and one of the second bus electrodes are arranged in a linearly continuous manner, 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 the hydrogen sensor of the present embodiment. As shown in FIG. 3, 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, one first bus electrode 5 and one 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 at intervals capable of detecting a change in the electrical resistance of the sensitive film 3. In FIG. 3, the first sensor electrodes 7 and the second sensor electrodes 8 are a pair of comb-shaped electrodes. The first bus electrode 5 and the second bus electrode 6 are arranged in a linearly continuous manner. In FIG. 3, the first bus electrode 5 and the second bus electrode 6 are arranged in a meandering line shape. Also, 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] In the hydrogen sensor shown in FIG. 3, as described above, by detecting a change in electrical resistance by the control unit, hydrogen gas can be detected. Also, in the hydrogen sensor shown in FIG. 3, there is one control unit, and by measuring the electrical resistance by one control unit, the position where the sensitive film reacts with hydrogen and the electrical resistance decreases can be specified.

[0031] FIG. 4 is a schematic plan view showing another example of the hydrogen sensor according to the present embodiment. The hydrogen sensor 1 shown in FIG. 4 is the same as 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] In the hydrogen sensor shown in FIG. 4, as described above, the hydrogen gas can be detected by detecting the change in the electrical resistance by the control unit. Further, in the hydrogen sensor shown in FIG. 4, the control unit has two first control unit 4a and second control unit 4b, and the position where the sensitive film 3 reacts with hydrogen and the electrical resistance decreases can be specified by 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] By using the hydrogen sensor of the present embodiment, as described above, hydrogen leakage can be detected at low cost even in a wide range, and further, the hydrogen leakage location can be specified.

[0034] Hereinafter, the hydrogen sensor of the present embodiment will be described for each configuration.

[0035] 1. First Sensor Electrode and Second Sensor Electrode In the present embodiment, a plurality of first sensor electrodes and a plurality of second sensor electrodes are arranged in contact with the sensitive film on the first surface of the substrate, and are arranged alternately at intervals capable of detecting a change in the electrical resistance of the sensitive film. The first sensor electrode is connected to the first bus electrode, the second sensor electrode is connected to the second bus electrode, and the first sensor electrode and the second sensor electrode are not connected.

[0036] In this specification, the "interval capable of detecting a change in the electrical resistance of the sensitive film" refers to an interval at which the first sensor electrode and the second sensor electrode can be short-circuited when the reduction reaction of the 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 capable of detecting changes in the electrical resistance of the sensitive film. For example, a pair of comb electrodes can be mentioned.

[0038] The interval between the first sensor electrode and the second sensor electrode may be an interval capable of detecting changes in the electrical resistance of the sensitive film. The above interval may be, for example, 100 μm or more, and may be 500 μm or more. Also, the above interval may be, for example, 10 mm or less, and may be 5 mm or less. That is, the above interval may be, for example, 100 μm or more and 10 mm or less, and may be 500 μm or more and 5 mm or less.

[0039] The interval between the first sensor electrode and the second sensor electrode refers to the distance from the end of the adjacent first sensor electrode to the end of the second sensor electrode. For example, in FIG. 3, the interval between the first sensor electrode and the second sensor electrode is indicated by d1.

[0040] The width of the first sensor electrode and the width of the second sensor electrode may be widths capable of detecting changes in the electrical resistance of the sensitive film. The above width may be, for example, 100 μm or more, and may be 500 μm or more. Also, the above width may be, for example, 10 mm or less, and may be 5 mm or less. That is, the above width may be, for example, 100 μm or more and 10 mm or less, and may be 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 length of the second sensor electrode may be lengths capable of detecting changes in the electrical resistance of the sensitive film. The above length may be, for example, 10 mm or more, and may be 50 mm or more. Also, the above length may be, for example, 500 mm or less, and may be 100 mm or less. That is, the above length may be, for example, 10 mm or more and 500 mm or less, and may be 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 overlapping length of the first sensor electrode and the second sensor electrode may be any length capable of detecting a change in the electrical resistance of the sensing film. For example, the overlapping length may be 9 mm or more, and may be 45 mm or more. Also, the overlapping length may be, for example, 450 mm or less, and may be 90 mm or less. That is, the overlapping length may be, for example, 9 mm or more and 450 mm or less, and may be 45 mm or more and 90 mm or less. For example, in FIG. 3, the overlapping length of the first sensor electrode and the second sensor electrode is indicated by c.

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

[0044] The shape of the first sensor electrode and the shape of the second sensor electrode are not particularly limited, and examples include linear, polygonal line, and curved. For example, in FIG. 3, the shape of the first sensor electrode 7 and the shape of the second sensor electrode 8 are linear. Also, for example, in FIG. 5, the shape of the first sensor electrode 7 is linear and polygonal line, and the shape of the second sensor electrode 8 is linear.

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

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

[0047] The method for forming the first sensor electrode and the method for forming the second sensor electrode are not particularly limited, and examples thereof include a method of forming a conductive film and patterning it, a mask evaporation method, and a printing method. Examples of the method for forming the conductive film include a vacuum evaporation 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 the present 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 the present embodiment has one first bus electrode and one second bus electrode. The first bus electrode and the second bus electrode are arranged in a linearly continuous manner that can be drawn in one stroke.

[0049] In this specification, "linearly continuous that can be drawn in one stroke" means that it consists of a single continuous line and has no overlapping parts.

[0050] The linearly continuous form that can be drawn in one stroke is not particularly limited as long as the first bus electrode, the second bus electrode, the first sensor electrode, and the second sensor electrode can be entirely arranged on the first surface of the substrate. Examples include a meandering shape as shown in FIGS. 3 and 4, and a spiral shape as shown in FIG. 5. Among them, it is preferable that the first bus electrode and the second bus electrode are arranged in a meandering shape. In this case, since the first bus electrode and the second bus electrode can be formed by a roll-to-roll method, the hydrogen sensor can be efficiently mass-produced.

[0051] The first bus electrode and the second bus electrode are arranged so as to be able to identify the position where the electrical resistance of the sensing film has changed. Specifically, since a plurality of first sensor electrodes connected to the first bus electrode and a plurality of second sensor electrodes connected to the second bus electrode are alternately arranged, the first bus electrode and the second bus electrode 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 can function as an electrode. The above width may be, for example, 1 mm or more, and may be 5 mm or more. Also, the above width may be, for example, 50 mm or less, and may be 10 mm or less. That is, the above 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 facing each other with the first sensor electrode and the second sensor electrode interposed therebetween may be any distance at which the first sensor electrode and the second sensor electrode can be arranged. The above distance may be, for example, 11 mm or more, and may be 55 mm or more. Also, the above distance may be, for example, 550 mm or less, and may be 110 mm or less. That is, the above distance may be, for example, 11 mm or more and 550 mm or less, and may be 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 facing each other with the first sensor electrode and the second sensor electrode interposed therebetween is indicated by f.

[0054] The distance between the first bus electrode and the second bus electrode facing each other without sandwiching the first sensor electrode and the second sensor electrode may be any distance at which a change in the electrical resistance of the sensing film cannot be detected. The above distance may be, for example, 10 mm or more, and may be 50 mm or more. Also, the above distance may be, for example, 100 mm or less, and may be 70 mm or less. That is, the above distance may be, for example, 10 mm or more and 100 mm or less, and may be 50 mm or more and 70 mm or less. If the above distance is too small, when the reduction reaction of the above tungsten oxide occurs and the electrical resistance of the sensing film decreases, the first bus electrode and the second bus electrode facing each other without sandwiching the first sensor electrode and the second sensor electrode are likely to conduct, and it may be difficult to identify the location of hydrogen leakage. For example, in FIG. 3, the distance between the first bus electrode and the second bus electrode facing each other without sandwiching the first sensor electrode and the second sensor electrode is indicated by g.

[0055] The distance between adjacent first bus electrodes and the distance between adjacent second bus electrodes may be any distance as long as it cannot detect a change in the electrical resistance of the sensing film. For example, the above distance may be 10 mm or more, and may be 50 mm or more. Also, the above distance may be, for example, 100 mm or less, and may be 70 mm or less. That is, the above distance may be, for example, 10 mm or more and 100 mm or less, and may be 50 mm or more and 70 mm or less. If the above distance is too small, when the reduction reaction of the above tungsten oxide occurs and the electrical resistance of the sensing film decreases, adjacent first bus electrodes or adjacent second bus electrodes are likely to conduct, making it difficult to identify the location of hydrogen leakage. 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 are a pair of electrodes, and the number of first bus electrodes and the number of second bus electrodes are usually one. Note that if 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, the hydrogen sensor 1 has two first bus electrodes 5a, 5b and two second bus electrodes 6a, 6b, the first bus electrode 5a and the second bus electrode 6a form a pair of electrodes, and the first bus electrode 5b and the 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 the same as the thickness of the first sensor electrode and the thickness of the second sensor electrode described above.

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

[0060] 3. Sensing Film The sensitive film in this embodiment contains a catalyst for dissociating 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 include noble metals such as palladium, platinum, and iridium. The catalyst may be used alone or in combination of two or more.

[0064] The tungsten oxide is tungsten trioxide (WO 3 ).

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

[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 can detect a change in the electrical resistance of the sensitive film. For example, it is 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 can detect a change in the electrical resistance of the tungsten oxide layer. For example, it is 100 nm or more and 3000 nm or less. Also, the thickness of the catalyst layer is, for example, 1 nm or more and 10 nm or less.

[0068] When the sensitive film is a single layer containing a catalyst and tungsten oxide, examples of the method for forming the sensitive film include the sol-gel method. For the method of forming the sensitive film by the sol-gel method, reference can be made to, for example, Japanese Patent No. 5152797 and Japanese Patent No. 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 include vacuum evaporation, sputtering, and ion plating. The method for forming the catalyst layer is also not particularly limited, and examples include vacuum evaporation, sputtering, and ion plating.

[0070] 4. Control Unit The control unit in the present embodiment is a member that detects a change in electrical resistance. A first bus electrode and a second bus electrode are connected to the control unit.

[0071] The control unit only needs to be able to detect a change in electrical resistance. For example, those having an IC chip that detects a change in electrical resistance can be mentioned. As the IC chip, an open-short type IC chip can be used. The open-short type is an IC chip that detects a change in electrical resistance by setting the flag to "1" when the resistance between terminals becomes equal to or less than a set value and setting the flag to "0" when it becomes equal to or greater than another set value. Also, a capacitance type IC chip may be used as the IC chip. The capacitance type is typically an IC chip that detects a change in impedance when water droplets or the like come into contact with an antenna and the antenna becomes detuned. In the present disclosure, when a capacitance type IC chip is used, the sensitive film is separately arranged in contact with the antenna of the IC tag described later, and the change in its impedance is detected. Among them, an open-short type IC chip is preferable. Examples of the open-short type IC chip include UCODE G2iM+ of NXP.

[0072] Specifically, as the control unit, an IC tag having the above IC chip and antenna is used. Note that an IC tag is also referred to as an RF tag, RFID tag, electronic tag, wireless tag, etc. As the IC tag, any tag having the above IC chip and antenna may be used, and a general IC tag can be used. If it is an IC tag, hydrogen gas can be detected using RFID.

[0073] IC tags include an active type with a built-in power source (battery) and a passive type without a built-in power source (battery). Among them, the passive type tag is preferable because it can obtain a driving power source by receiving radio waves supplied from the outside with an antenna and operate without mounting a power source (battery) itself.

[0074] An example of the operating principle of the hydrogen sensor in the present disclosure when the control unit is an IC tag will be described. As described above, in an atmosphere where hydrogen is absent, the sensing 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. Therefore, even when power is supplied from an external device to the IC tag, no current flows through the sensing film to the first sensor electrode and the second sensor electrode. On the other hand, in an atmosphere where hydrogen is present, the reduction reaction of the above tungsten oxide occurs, and the sensing film has a reduced electrical resistance and becomes conductive. At this time, the first sensor electrode and the second sensor electrode are short-circuited and become conductive. Therefore, when power is supplied from an external device to the IC tag, current flows through the sensing film to the first sensor electrode and the second sensor electrode. In the IC chip, the value of the electrical resistance is measured, information is detected from the value of the electrical resistance, and a signal corresponding to the information is transmitted to an external device. In the external device, based on the above information, hydrogen leakage is detected and the location of the hydrogen leakage is specified.

[0075] The control unit is at least one. The control unit may be one, or may have two control units, namely 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 one control unit. When the control unit has two control units, namely 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] Among them, it is preferable that the control unit has two control units, namely a first control unit and a second control unit. As described above, when the control units are connected to both ends of the first bus electrode and both ends of the second bus electrode, the position where the sensitive film reacts with hydrogen and the electrical resistance decreases can be specified by the difference between the electrical resistance measured by the first control unit and the electrical resistance measured by the second control unit. Therefore, an increase in the electrical resistance due to the lengths of the first bus electrode and the second bus electrode can be suppressed, and the electrical load on the control unit can be reduced. Thus, the reliability can be further enhanced, and the accuracy of the hydrogen sensor can be improved.

[0077] 5. Substrate The substrate in this embodiment is a member that supports the above-mentioned sensitive film, first sensor electrode, second sensor electrode, first bus electrode, and second bus electrode and has insulation properties.

[0078] The substrate is not particularly limited as long as it has insulation 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 for example, it is 10 μm or more and 2 mm or less.

[0080] 6. Other configurations In this embodiment, it is sufficient that the above-mentioned sensing film, first sensor electrode, second sensor electrode, first bus electrode, and second bus electrode are arranged on the first surface of the substrate. The above-mentioned sensing film, first sensor electrode, second sensor electrode, first bus electrode, and second bus electrode may be arranged on only one side of the substrate, or the above-mentioned sensing film, first sensor electrode, second sensor electrode, first bus electrode, and second bus electrode may be arranged on both sides of the substrate, respectively.

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

[0082] II. Second Embodiment The first embodiment of the hydrogen sensor in the present disclosure is the above-mentioned hydrogen sensor, in which a plurality of the first bus electrodes and a plurality of the 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 the hydrogen sensor of this embodiment. As shown in FIG. 7, the hydrogen sensor 1 includes a substrate 2, a sensing film 3 disposed on the first surface of the substrate 2 and containing a catalyst for dissociating hydrogen gas into hydrogen atoms and tungsten oxide, a control unit 4 for detecting a change 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 in contact with the sensing film 3 on the first surface of the substrate 2 and connected to the first bus electrodes 5, and a plurality of second sensor electrodes 8 disposed in contact with the sensing film 3 on the first surface of the substrate 2 and connected to the second bus electrodes 6. The first sensor electrodes 7 and the second sensor electrodes 8 are alternately arranged at intervals capable of detecting a change in the electrical resistance of the sensing film 3. In FIG. 7, the first sensor electrodes 7 and the second sensor electrodes 8 are a pair 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] In the hydrogen sensor shown in FIG. 7, as described above, the hydrogen gas can be detected by the control unit detecting the change in electrical resistance. Further, in the hydrogen sensor shown in FIG. 7, there is one control unit, and by measuring the electrical resistance with one control unit, the position where the sensing film reacts with hydrogen and the electrical resistance decreases can be specified.

[0085] FIG. 8 is a schematic plan view showing another example of the hydrogen sensor of the present embodiment. The hydrogen sensor 1 shown in FIG. 8 is the same as the hydrogen sensor 1 shown in FIG. 7 above, except that the control unit has 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] In the hydrogen sensor shown in FIG. 8, as described above, the hydrogen gas can be detected by the control unit detecting the change in electrical resistance. Further, in the hydrogen sensor shown in FIG. 8, the control unit has two, namely the first control unit 4a and the second control unit 4b, and the position where the sensing film 3 reacts with hydrogen and the electrical resistance decreases can be specified by 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] By using the hydrogen sensor of the present embodiment, as described above, hydrogen leakage can be detected at low cost even in a wide range, and further, the hydrogen leakage location can be specified. Also, in the present embodiment, compared with the first embodiment, the lengths of the first bus electrode and the second bus electrode can be shortened, so an increase in electrical resistance due to the lengths of the first bus electrode and the second bus electrode can be suppressed. Therefore, the accuracy of the hydrogen sensor can be improved.

[0088] Also, in the present embodiment, since the first bus electrode and the second bus electrode can be arranged linearly, the risk of disconnection can be reduced.

[0089] Hereinafter, the hydrogen sensor of the present embodiment will be described for each configuration.

[0090] 1. The first sensor electrode and the second sensor electrode In the present embodiment, a plurality of first sensor electrodes and a plurality of second sensor electrodes are arranged in contact with the sensing film on the first surface of the substrate, and are alternately arranged at intervals capable of detecting changes in the electrical resistance of the sensing film. The first sensor electrode is connected to the first bus electrode, and the second sensor electrode is connected to the second bus electrode, and the first sensor electrode and the second sensor electrode are not connected to each other.

[0091] The interval between the first sensor electrode and the second sensor electrode may be any interval capable of detecting changes in the electrical resistance of the sensing film. The interval may be, for example, 100 μm or more, and may be 500 μm or more. Also, the interval may be, for example, 10 mm or less, and may be 5 mm or less. That is, the interval may be, for example, 100 μm or more and 10 mm or less, and may be 500 μm or more and 5 mm or less.

[0092] The interval between the first sensor electrode and the second sensor electrode refers to the distance from the end of an adjacent first sensor electrode to the end of the second sensor electrode. For example, in FIG. 7, the interval between the first sensor electrode and the second sensor electrode is indicated by d1.

[0093] The width of the first sensor electrode and the width of the second sensor electrode may be any width capable of detecting changes in the electrical resistance of the sensing film. The width may be, for example, 100 μm or more, and may be 500 μm or more. Also, the width may be, for example, 10 mm or less, and may be 5 mm or less. That is, the width may be, for example, 100 μm or more and 10 mm or less, and may be 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 length of the second sensor electrode only need to be lengths capable of detecting a change in the electrical resistance of the sensing film. The above lengths may be, for example, 10 mm or more, and may be 50 mm or more. Also, the above lengths may be, for example, 500 mm or less, and may be 100 mm or less. That is, the above lengths may be, for example, 10 mm or more and 500 mm or less, and may be 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 overlapping length of the first sensor electrode and the second sensor electrode only need to be a length capable of detecting a change in the electrical resistance of the sensing film. The above overlapping length may be, for example, 9 mm or more, and may be 45 mm or more. Also, the above overlapping length may be, for example, 450 mm or less, and may be 90 mm or less. That is, the above overlapping length may be, for example, 9 mm or more and 450 mm or less, and may be 45 mm or more and 90 mm or less. For example, in FIG. 7, the overlapping length of the first sensor electrode and the second sensor electrode is indicated by c.

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

[0097] The shape of the first sensor electrode and the shape of the second sensor electrode are not particularly limited, and examples thereof include a linear shape, a polygonal line shape, and a curved shape.

[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 formation method of 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 above first embodiment.

[0099] 2. First bus electrode and second bus electrode In the present embodiment, the first bus electrode and the second bus electrode are arranged on the first surface of the substrate and are connected to the control unit. The hydrogen sensor of the present 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 can function as an electrode. The above width may be, for example, 1 mm or more, and may be 5 mm or more. Also, the above width may be, for example, 50 mm or less, and may be 10 mm or less. That is, the above 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 at which the first sensor electrode and the second sensor electrode can be arranged. The above distance may be, for example, 11 mm or more, and may be 55 mm or more. Also, the above distance may be, for example, 550 mm or less, and may be 110 mm or less. That is, the above distance may be, for example, 11 mm or more and 550 mm or less, and may be 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 the first bus electrodes and the number of the second bus electrodes are plural. The first bus electrode and the second bus electrode only need to be a pair of electrodes, and the number of the first bus electrodes and the number of the second bus electrodes may be the same or different. For example, in FIG. 7, there are 4 first bus electrodes 5 and 5 second bus electrodes 6, and the number of the first bus electrodes and the number of the 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 the same as the thickness of the first sensor electrode and the thickness of the second sensor electrode described above.

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

[0107] 3. Sensing film The sensing film in this embodiment includes a catalyst for dissociating hydrogen gas into hydrogen atoms and tungsten oxide. The sensing film is the same as the sensing film in the first embodiment.

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

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

[0110] There is at least one control unit. The control unit may be one, or may have two control units, namely 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 one control unit. When the control unit has two control units, namely 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 board In this embodiment, a plurality of first bus electrodes and a plurality of second bus electrodes are connected to the control unit via a flexible printed circuit board (FPC). As the FPC, a general FPC can be used.

[0112] 6. Substrate The substrate in this embodiment is a member that supports the sensing film, the first sensor electrode, the second sensor electrode, the first bus electrode, and the second bus electrode and has insulating properties. 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-described hydrogen sensor, wherein 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 orthogonal to the first direction, the control unit includes a third control unit connected to one end of the plurality of the first bus electrodes and a fourth control unit connected to one end of the plurality of the second bus electrodes, and 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.

[0114] FIG. 9 is a schematic plan view showing an example of the hydrogen sensor of the present embodiment. As shown in FIG. 9, the hydrogen sensor 1 includes a substrate 2, a sensitive film 3 disposed on a first surface of the substrate 2 and containing a catalyst for dissociating hydrogen molecules and tungsten oxide, a third control unit 4c and a fourth control unit 4d for detecting a change 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 disposed on the first surface of the substrate 2 and 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 film 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 film 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 capable of detecting a change in the electrical resistance of the sensitive film 3. In FIG. 9, the first sensor electrodes 7 and the second sensor electrodes 8 are a pair of comb-shaped electrodes. The plurality of first bus electrodes 5 are linearly arranged in a first direction D1, and the plurality of second bus electrodes 6 are linearly arranged in a second direction D2 orthogonal to the first direction D1. The control unit includes a third control unit 4c connected to one end of the plurality of first bus electrodes 5 and a fourth control unit 4d connected to one end of the plurality of second bus electrodes 6. An insulating film 11 is disposed between the first bus electrode 5 and the second bus electrode 6 in a region where the first bus electrode 5 and the second bus electrode 6 intersect.

[0115] In the hydrogen sensor shown in FIG. 9, as described above, by detecting a change in electrical resistance by the control unit, hydrogen gas can be detected. Further, in the hydrogen sensor shown in FIG. 9, by measuring the electrical resistance by the third control unit and the fourth control unit, among the intersections of the first bus electrode and the second bus electrode, the intersection of the first bus electrode and the second bus electrode where the electrical resistance has decreased can be specified. Therefore, the intersection of the first bus electrode and the second bus electrode where the electrical resistance has decreased can be specified as the position where the sensing film has reacted with hydrogen and the electrical resistance has decreased.

[0116] By using the hydrogen sensor of the present embodiment, as described above, hydrogen leakage can be detected at low cost even in a wide range, and further, the hydrogen leakage location can be specified.

[0117] Further, in the present embodiment, since it is not necessary to arrange the first bus electrode and the second bus electrode in a linear shape that can be drawn in one stroke, the risk of disconnection can be reduced. Further, as shown in FIG. 9, since the area of the overlapping portion 10C of the first sensor electrode 7 and the second sensor electrode 8 can be made constant, the variation in signals is reduced and the detection sensitivity is improved.

[0118] Hereinafter, the hydrogen sensor of the present embodiment will be described for each configuration.

[0119] 1. First Sensor Electrode and Second Sensor Electrode In the present embodiment, a plurality of first sensor electrodes and a plurality of second sensor electrodes are arranged in contact with the sensing film on the first surface of the substrate, and are arranged alternately at intervals capable of detecting a change in the electrical resistance of the sensing film. The first sensor electrode is connected to the first bus electrode, the second sensor electrode is connected to the second bus electrode, and the first sensor electrode and the second sensor electrode are not connected.

[0120] The plurality of first sensor electrodes and the plurality of second sensor electrodes may be those arranged alternately at intervals capable of detecting a change in the electrical resistance of the sensing film. For example, a pair of comb teeth electrodes may be mentioned.

[0121] The distance between the first sensor electrode and the second sensor electrode may be any distance that can detect a change in the electrical resistance of the sensing film. For example, the above distance may be 100 μm or more, and may be 500 μm or more. Also, the above distance may be, for example, 10 mm or less, and may be 5 mm or less. That is, the above distance may be, for example, 100 μm or more and 10 mm or less, and may be 500 μm or more and 5 mm or less.

[0122] The distance between the first sensor electrode and the second sensor electrode refers to the distance from the end of the adjacent first sensor electrode to the end of the second sensor electrode. For example, in FIG. 9, the distance between the first sensor electrode and the second sensor electrode 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 a change in the electrical resistance of the sensing film. For example, the above width may be 100 μm or more, and may be 500 μm or more. Also, the above width may be, for example, 10 mm or less, and may be 5 mm or less. That is, the above width may be, for example, 100 μm or more and 10 mm or less, and may be 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 length of the second sensor electrode may be any length that can detect a change in the electrical resistance of the sensing film. For example, the above length may be 10 mm or more, and may be 50 mm or more. Also, the above length may be, for example, 500 mm or less, and may be 100 mm or less. That is, the above length may be, for example, 10 mm or more and 500 mm or less, and may be 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 overlapping length of the first sensor electrode and the second sensor electrode may be any length capable of detecting a change in the electrical resistance of the sensing film. For example, the overlapping length may be 9 mm or more, and may be 45 mm or more. Also, the overlapping length may be, for example, 450 mm or less, and may be 90 mm or less. That is, the overlapping length may be, for example, 9 mm or more and 450 mm or less, and may be 45 mm or more and 90 mm or less. For example, in FIG. 9, the overlapping length of the first sensor electrode and the second sensor electrode is indicated by c.

[0126] The number of the first sensor electrodes and the number of the second sensor electrodes are appropriately set according to the size of the hydrogen sensor, the arrangement of the first bus electrode, the arrangement of the second bus electrode, etc.

[0127] The shape of the first sensor electrode and the shape of the second sensor electrode are not particularly limited, and examples thereof include linear, polygonal line, and curved. Also, the shape of the first sensor electrode and the shape of the second sensor electrode may be a shape having a branch. For example, in FIG. 9, the shape of the first sensor electrode 7 is linear, and the shape of the second sensor electrode 8 is a shape having a branch. Also, for example, in FIG. 10, the shape of the first sensor electrode 7 is linear, and the shape of the second sensor electrode 8 is polygonal line.

[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.

[0129] 2. First bus electrode and second bus electrode In the present embodiment, the first bus electrode and the second bus electrode are disposed on the first surface of the substrate and are connected to the control unit. The hydrogen sensor of the present embodiment has a plurality of first bus electrodes and a plurality of second bus electrodes. The first bus electrodes are arranged along the first direction, and the second bus electrodes are arranged along the second direction orthogonal 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 can function as an electrode. For example, the above width may be 1 mm or more, and may be 5 mm or more. Also, the above width may be 50 mm or less, and may be 10 mm or less. That is, the above 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 at which the first sensor electrode and the second sensor electrode can be arranged. For example, the above distance may be 11 mm or more, and may be 55 mm or more. Also, the above distance may be 550 mm or less, and may be 110 mm or less. That is, the above distance may be, for example, 11 mm or more and 550 mm or less, and may be 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 first bus electrodes and the number of 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 the same as the thickness of the first sensor electrode and the thickness of the second sensor electrode described above.

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

[0136] 3. Sensing film The sensing film in the present embodiment includes a catalyst that dissociates hydrogen molecules and tungsten oxide. The sensing film is the same as the sensing film in the first embodiment described above.

[0137] The sensing film only needs to be arranged in contact with the first sensor electrode and the second sensor electrode, and the position of the sensing film is not particularly limited. For example, on the first surface of the substrate, the first sensor electrode, the second sensor electrode, and the sensing film may be arranged in this order, or on the first surface of the substrate, the sensing film, the first sensor electrode, and the second sensor electrode may be arranged in this order, or on the first surface of the substrate, the first sensor electrode, the sensing film, and the second sensor electrode may be arranged in this order, or on the first surface of the substrate, the second sensor electrode, the sensing film, and the first sensor electrode may be arranged in this order.

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

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

[0140] The control unit includes a third control unit connected to one end of a plurality of first bus electrodes and a fourth control unit connected to one end of a plurality of second bus electrodes. Further, the control unit may include the third control unit, the fourth control unit, and a fifth control unit connected to the other end of the plurality of first bus electrodes. Further, the control unit may include the third control unit, the fourth control unit, and a sixth control unit connected to the other end of the plurality of second bus electrodes. Further, the control unit may 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 end of a plurality of first bus electrodes 5, a fourth control unit 4d connected to one end of a plurality of second bus electrodes 6, and a fifth control unit 4e connected to the other end of the plurality of first bus electrodes 5.

[0141] 5. Substrate The substrate in this embodiment is a member that supports the above sensing film, first sensor electrode, second sensor electrode, first bus electrode, and second bus electrode and has insulating properties. The substrate is the same as the substrate in the above first embodiment.

[0142] 6. Insulating film In this embodiment, the 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.

[0143] The material of the insulating film is not particularly limited as long as it is a material having insulating properties, 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 can insulate the first bus electrode and the second bus electrode, and for example, it is 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 and patterning the insulating film, a mask evaporation method, and a printing method. Examples of the method for forming the insulating film include a vacuum evaporation 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 in the present disclosure uses the above-described hydrogen sensor.

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

[0148] FIG. 13 is a schematic diagram showing another example of the hydrogen detection system in the present disclosure. In FIG. 12, the hydrogen detection system 20 includes a plurality of hydrogen sensors 1, an RFID reader / writer 21, and an antenna 22 connected to the RFID reader / writer 21. The hydrogen sensor 1 is attached to a hydrogen pipeline 30 installed underground. The RFID reader / writer 21 and the antenna 22 are installed in a moving body 23 and are mobile.

[0149] In such a hydrogen detection system, it is possible to drive an IC chip constituting a control unit of the hydrogen sensor non - contact, detect a change in the electrical resistance of the sensitive film, and detect hydrogen gas.

[0150] The hydrogen detection system in the present disclosure is not particularly limited as long as it is a system using a hydrogen sensor, but is preferably a system using RFID. Specifically, the hydrogen detection system in 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 fixed or mobile. When a fixed RFID reader / writer is used, continuous monitoring becomes possible. On the other hand, when a mobile RFID reader / writer is used, trace inspection can be performed, and it is possible to enhance, smarten, and reduce the man - power of the trace inspection.

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

[0153] C. Sheet for Hydrogen Sensor The hydrogen sensor sheet in the present disclosure is a roll-shaped hydrogen sensor sheet, which includes a substrate, a sensing film disposed on the first surface of the substrate and containing a catalyst for dissociating hydrogen molecules and tungsten oxide, a bus electrode disposed on the first surface of the substrate and arranged in a meandering line shape, 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 sensing film and connected to the bus electrode. The first sensor electrodes and the second sensor electrodes are alternately arranged at intervals capable of detecting a change in the electrical resistance of the sensing film.

[0154] FIG. 14 is a schematic perspective view showing an example of the hydrogen sensor sheet in the present disclosure, and FIG. 15 is a schematic plan view showing an example of the hydrogen sensor sheet in the present disclosure. As shown in FIG. 14, the hydrogen sensor sheet 40 is in a roll shape. As shown in FIG. 15, the hydrogen sensor sheet 40 includes a substrate 2, a sensing film 3 disposed on the first surface of the substrate 2 and containing a catalyst for dissociating hydrogen molecules and tungsten oxide, a bus electrode 41 disposed on the first surface of the substrate 2 and arranged in a meandering line shape, and a plurality of first sensor electrodes 7 and a plurality of second sensor electrodes 8 disposed on the first surface of the substrate 2 in contact with the sensing film 3 and connected to the bus electrode 41. The first sensor electrodes 7 and the second sensor electrodes 8 are alternately arranged at intervals capable of detecting a change in the electrical resistance of the sensing film 3.

[0155] The hydrogen sensor sheet in the present disclosure is used for manufacturing the above-described hydrogen sensor. Since the hydrogen sensor sheet in the present disclosure can be manufactured by a roll-to-roll method, the hydrogen sensor can be efficiently mass-produced.

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

[0157] When manufacturing the above hydrogen sensor using the sheet for a hydrogen sensor in the present disclosure, the sheet for a hydrogen sensor is cut according to the target length, and the bus electrodes at the portion where the control unit is to be connected are cut. Then, the control unit is arranged.

[0158] Note that the present disclosure is not limited to the above-described embodiments. The above-described embodiments are examples, and any configuration that has substantially the same configuration as the technical idea described in the claims of the present disclosure and exhibits the same operational effects is included in the technical scope of the present disclosure.

Example

[0159] Hereinafter, examples will be shown to explain the present disclosure in more detail.

[0160] A hydrogen sensor shown in FIG. 4 was fabricated. On a polyethylene terephthalate (PET) film with a thickness of 50 μm, a first bus electrode, a second bus electrode, a first sensor electrode, and a second sensor electrode were formed by a printing method. 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 overlapping length c of the first sensor electrode and the second sensor electrode was 50 mm, the interval 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 interval f between the first bus electrode and the second bus electrode facing each other with the first sensor electrode and the second sensor electrode interposed therebetween was 90 mm, the interval g between the first bus electrode and the second bus electrode facing each other without sandwiching the first sensor electrode and the second sensor electrode was 10 mm, the interval h1 between adjacent first bus electrodes and the interval h2 between adjacent second bus electrodes were 10 mm. Also, the thickness of the first bus electrode, the thickness of the second bus electrode, the thickness of the first sensor electrode, and the thickness of the second sensor electrode were each 0.2 μm. Next, a sensitive film was formed by a sol-gel method so as to cover the first bus electrode, the second bus electrode, the first sensor electrode, and the second sensor electrode on the PET film. Next, an IC tag was connected to and mounted on the first bus electrode and the second bus electrode. Thereby, a hydrogen sensor was obtained.

[0161] It was confirmed that the above hydrogen sensor can transmit a reading radio wave with an RFID reader / writer and detect the radio wave reflected and transmitted. Further, when the radio wave was transmitted in the same manner while exposing the above hydrogen sensor to hydrogen gas, the signal level of the radio wave reflected and transmitted changed. Thereby, it was confirmed that hydrogen gas can be detected without mounting a power source on the hydrogen sensor itself.

[0162] Also, taking the resistance value R1 measured by the first control unit and the resistance value R2 measured by the second control unit, the coefficient obtained by dividing R1 by the total resistance value (R1 + R2) was multiplied by the total length of the first bus electrode or the second bus electrode to identify the leakage position from the first control unit. Although the resistance value changes depending on the concentration of hydrogen, the leakage position could be accurately identified by the above method regardless of the hydrogen concentration.

[0163] In the present disclosure, the following inventions are provided. [1] A substrate, A sensitive film containing a catalyst for dissociating hydrogen molecules and tungsten oxide, disposed on the first surface of the above substrate, A control unit for detecting a change in electrical resistance, A first bus electrode and a second bus electrode, disposed on the first surface of the above substrate and connected to the above control unit, A plurality of first sensor electrodes, disposed in contact with the above sensitive film on the first surface of the above substrate and connected to the above first bus electrode, A plurality of second sensor electrodes, disposed in contact with the above sensitive film on the first surface of the above substrate and connected to the above second bus electrode, and having The above first sensor electrodes and the above second sensor electrodes are alternately arranged at intervals capable of detecting a change in the electrical resistance of the above sensitive film, a hydrogen sensor. [2] One of the above first bus electrodes and one of the above second bus electrodes are arranged in a linearly continuous manner, One end of the above first bus electrode and one end of the above second bus electrode are connected to the above control unit, the hydrogen sensor according to [1]. [3] The hydrogen sensor according to [2], wherein the control unit includes 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 meandering line shape. [5] The hydrogen sensor according to [1], wherein a plurality of the first bus electrodes and a plurality of the 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 orthogonal to the first direction, The control unit includes a third control unit connected to one end of a plurality of the first bus electrodes and a fourth control unit connected to one end of a plurality of the second bus electrodes, The hydrogen sensor according to [1], wherein an insulating film is arranged 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 sheet for a hydrogen sensor, comprising: a substrate, a sensitive film containing a catalyst for dissociating hydrogen molecules and tungsten oxide, disposed on a first surface of the substrate, bus electrodes arranged in a meandering line shape, disposed on the first surface of the substrate, a plurality of first sensor electrodes and a plurality of second sensor electrodes disposed in contact with the sensitive film on the first surface of the substrate and connected to the bus electrodes. In the hydrogen sensor sheet, the first sensor electrodes and the second sensor electrodes are alternately arranged at intervals capable of detecting a change in the electrical resistance of the sensitive film.

Description of Reference Numerals

[0164] 1 … Hydrogen sensor 2 … Substrate 3 … Sensing film 4 … Control unit 4a … First control unit 4b … Second control unit 4c … Third control unit 4d … Fourth control unit 5 … First bus electrode 6 … Second bus electrode 7 … First sensor electrode 8 … Second sensor electrode 20 … Hydrogen detection system 40 … Sheet for hydrogen sensor

Claims

1. A substrate, a sensitive film disposed on the first surface of the substrate, containing a catalyst for dissociating hydrogen molecules and tungsten oxide, a control unit for detecting a change 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 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, and having, the first sensor electrodes and the second sensor electrodes are alternately arranged at intervals capable of detecting a change in the electrical resistance of the sensitive film, a hydrogen sensor, wherein the control unit is an IC tag having an IC chip and an antenna for detecting a change in electrical resistance.

2. One of the first bus electrodes and one of the second bus electrodes are arranged in a linearly continuous manner, One end of the first bus electrode and one end of the second bus electrode are connected to the control unit. The hydrogen sensor according to claim 1.

3. A substrate, a sensitive film disposed on the first surface of the substrate, containing a catalyst for dissociating hydrogen molecules and tungsten oxide, a control unit for detecting a change 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 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, and having, the first sensor electrodes and the second sensor electrodes are alternately arranged at intervals capable of detecting a change in the electrical resistance of the sensitive film, A hydrogen sensor, wherein a plurality of the first bus electrodes and a plurality of the 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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