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

Abstract

To provide a hydrogen sensor capable of detecting hydrogen gas even in a wide range and also specifying a hydrogen leakage location.SOLUTION: The present disclosure provides a hydrogen sensor comprising: a substrate; a sensitive membrane arranged on a first surface of the substrate, and including a catalyst for dissociating hydrogen gas into hydrogen atoms and tungsten oxide; a control unit that detects change in electrical resistance; a first bus electrode and a second bus electrode arranged on the first surface of the substrate, and connected to the control unit; a plurality of first sensor electrodes arranged 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 arranged on the first surface of the substrate in contact with the sensitive membrane, and connected to the second bus electrode, where the first sensor electrodes and the second sensor electrodes are alternately arranged at intervals allowing detection of change in the electrical resistance of the sensitive membrane.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 demand for the use of clean and recyclable energy sources from the perspective of protecting the global environment and preventing the depletion of fossil fuels. In particular, active research into the use of hydrogen gas as an energy source has been conducted, focusing on fuel cells. However, hydrogen gas has a wide explosive limit concentration range, from 4% to 75%, and in order to popularize hydrogen gas as an energy source, it is essential to handle hydrogen storage and transportation, as well as to develop safety devices to prevent hydrogen leaks.

[0003] For example, odorization, which is used for 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 to replace odorization are required. Therefore, to ensure safety, hydrogen sensors that detect hydrogen gas leaks have become very important.

[0004] Conventional hydrogen sensors mainly use the catalytic combustion or semiconductor type. In catalytic combustion type hydrogen sensors, a catalytic metal such as platinum or palladium is heated with a heater, and hydrogen gas that comes into contact with the catalyst is oxidized with oxygen in the air. The heat generated by the oxidation of this hydrogen gas is electrically detected as a change in the conductivity of the catalytic metal. In addition, semiconductor type hydrogen sensors detect changes in the electrical properties of the sensitive film caused by the adsorption of hydrogen gas to the sensitive film, that is, changes in electrical resistance. Like the catalytic combustion type, this semiconductor type hydrogen sensor is also used in a heated state with a heater. As such, conventional hydrogen sensors such as the catalytic combustion type and semiconductor type pose a risk when used with hydrogen gas that requires explosion-proofing because they involve heating.

[0005] Furthermore, gasochromic hydrogen sensors have been attracting attention in recent years. Gasochromic hydrogen sensors are equipped with a metal oxide such as tungsten trioxide, which changes color when hydrogen is adsorbed, and a catalyst such as platinum, which dissociates hydrogen gas into hydrogen atoms, and detect hydrogen gas optically. Metal oxides such as tungsten trioxide also change their electrical properties when hydrogen is adsorbed, so 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] JP 2002-328108 A Summary of the Invention [Problem to be solved by the invention]

[0007] Conventional hydrogen sensors, such as those using catalytic combustion or semiconductor methods, detect hydrogen gas at the location where they are installed. Therefore, they can only detect hydrogen gas in a small area. It is also difficult to identify the location of the hydrogen leak.

[0008] The present disclosure has been made in consideration of the above-mentioned circumstances, and has as its main object to provide a hydrogen sensor that can detect hydrogen gas over a wide range and 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, the sensitive membrane including a catalyst for dissociating hydrogen molecules and tungsten oxide; a control unit for detecting 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, the first sensor electrodes and the second sensor electrodes being alternately arranged at intervals allowing 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 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 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 allowing a change in the electrical resistance of the sensitive membrane to be detected. Effect of the Invention

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

[0013] [Figure 1] 1 is a schematic plan view illustrating a hydrogen sensor according to the present disclosure. [Diagram 2] 1 is a schematic plan view illustrating a hydrogen sensor according to the present disclosure. [Diagram 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. [Diagram 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 in the present disclosure. [Figure 13] FIG. 1 is a schematic diagram illustrating a hydrogen detection system in 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 sheet for a hydrogen sensor according to the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The following describes the embodiments of the present disclosure with reference to the drawings. However, the present disclosure can be implemented in many different forms, and is not to be construed as being limited to the description of the embodiments exemplified below. In addition, in order to make the explanation clearer, the drawings may be schematic in terms of the width, thickness, shape, etc. of each member compared to the embodiments, but these are merely examples and do not limit the interpretation of the present disclosure. In this specification and each figure, elements similar to those described above with respect to the previously mentioned figures may be given the same reference numerals, and detailed explanations 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 face side" or "on the face" is used, unless otherwise specified, it 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] In addition, in this specification, the terms "sheet," "film," "plate," and the like are not distinguished from one another solely on the basis of 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 disclosed herein comprises a substrate, a sensitive membrane arranged 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 arranged on the first surface of the substrate and connected to the control unit, a plurality of first sensor electrodes arranged 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 arranged 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 an interval that allows 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 dissociate and adsorb 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 reduction reaction of tungsten oxide occurs, and the sensitive 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.

[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 hydrogen sensors such as semiconductor and catalytic combustion types require heating and can only detect hydrogen gas over a narrow range. In contrast, the reduction reaction of tungsten oxide does not require the supply of electricity. Therefore, the hydrogen sensor of the present disclosure can be made large in area and can detect hydrogen gas over a relatively wide range at low cost. Therefore, by using the hydrogen sensor of the present disclosure, hydrogen gas leakage 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] In addition, the electrical resistance of a conductor is proportional to the length of the conductor. Therefore, as illustrated in FIG. 2, the value of the electrical resistance measured by the control unit 4 is different between the case where the reduction reaction of tungsten oxide occurs in the region 10A, the electrical resistance of the sensitive film 3 decreases, and the first sensor electrode 7 and the second sensor electrode 8 are shorted, and the case where the reduction reaction of tungsten oxide occurs in the region 10B, the electrical resistance of the sensitive film 3 decreases, and the first sensor electrode 7 and the second sensor electrode 8 are shorted. Therefore, by measuring the electrical resistance with the control unit 4, the position where the sensitive film 3 reacts with hydrogen and the electrical resistance decreases can be identified. Therefore, by using the hydrogen sensor of the present disclosure, the hydrogen leakage location can be identified.

[0026] In this manner, 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 according to 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 the hydrogen sensor of this embodiment. As shown in FIG. 3, the hydrogen sensor 1 has a substrate 2, a sensitive film 3 that is disposed on the first surface of the substrate 2 and contains a catalyst that dissociates hydrogen molecules and tungsten oxide, a control unit 4 that detects changes in electrical resistance, one first bus electrode 5 and one second bus electrode 6 that are disposed on the first surface of the substrate 2 and connected to the control unit 4, a plurality of first sensor electrodes 7 that are 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 that are 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 that allow the change in electrical resistance of the sensitive film 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 Fig. 3 can detect hydrogen gas by detecting changes in electrical resistance with the control unit. The hydrogen sensor shown in Fig. 3 has one control unit, and by measuring electrical resistance with the one control unit, the position where the sensitive film has reacted with hydrogen and the electrical resistance has decreased can be identified.

[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 the change in electrical resistance with the control unit. In addition, 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 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.

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

[0034] Each component of the hydrogen sensor of this embodiment will be described below.

[0035] 1. First sensor electrode and second sensor electrode In this embodiment, the first sensor electrodes and the 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-teeth electrodes.

[0038] The distance between the first sensor electrode and the second sensor electrode may be any distance that allows the change in the electrical resistance of the sensitive film to be detected. 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 interval between the first sensor electrode and the second sensor electrode means the distance from the end of the first sensor electrode to the end of the second sensor electrode adjacent to each other. For example, in FIG. 3, the interval between the first sensor electrode and the second sensor electrode is indicated as d1.

[0040] The width of the first sensor electrode and the width of the second sensor electrode may be any width that allows detection of a change in the electrical resistance of the sensitive film. 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 length of the second sensor electrode may be any length that allows the change in the electrical resistance of the sensitive film to be detected. The length may be, for example, 10 mm or more, and may be 50 mm or more. The length may be, for example, 500 mm or less, and may be 100 mm or less. That is, the 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 overlap length of the first sensor electrode and the second sensor electrode may be any length that allows detection of a change in the electrical resistance of the sensitive film. The overlap length may be, for example, 9 mm or more, and may be 45 mm or more. The overlap length may be, for example, 450 mm or less, and may be 90 mm or less. That is, the overlap 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 overlap length of 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 appropriately set depending on the size of the hydrogen sensor, the arrangement of the first bus electrodes, and the arrangement of the second bus electrodes, etc.

[0044] The shapes of the first sensor electrode and the second sensor electrode are not particularly limited, and may be, for example, linear, bent, 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 bent, and the second sensor electrode 8 is linear.

[0045] Examples of the conductive material used for the first and second sensor electrodes include carbon and metal materials. Among them, carbon is preferable. Carbon is inactive to hydrogen gas and is inexpensive. As 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 inactive 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 since 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 of forming the first sensor electrode and the method of 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 deposition method, and a printing method. Examples of the method of forming the conductive film include a vacuum 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 a single continuous line and has no overlapping portions.

[0050] The linear shape 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 arranged entirely over the 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 the second bus electrode are arranged in a meandering linear shape. In this case, the first bus electrode and the second bus electrode can be formed by a roll-to-roll method, allowing efficient mass production of hydrogen sensors.

[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 sensitive film has changed. 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 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 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 interval between the first bus electrode and the second bus electrode facing each other with the first sensor electrode and the second sensor electrode sandwiched therebetween may be any interval at which the first sensor electrode and the second sensor electrode can be arranged. The interval may be, for example, 11 mm or more and 55 mm or more. The interval may be, for example, 550 mm or less and 110 mm or less. That is, the interval may be, for example, 11 mm or more and 550 mm or less and 55 mm or more and 110 mm or less. For example, in FIG. 3, the interval between the first bus electrode and the second bus electrode facing each other with the first sensor electrode and the second sensor electrode sandwiched therebetween is indicated by f.

[0054] The interval between the first and second bus electrodes facing each other without sandwiching the first and second sensor electrodes may be any interval that does not allow detection of a change in the electrical resistance of the sensitive film. The interval may be, for example, 10 mm or more, and may be 50 mm or more. The interval may be, for example, 100 mm or less, and may be 70 mm or less. That is, the interval may be, for example, 10 mm or more and 100 mm or less, and 50 mm or more and 70 mm or less. If the interval is too small, when the reduction reaction of the tungsten oxide occurs and the electrical resistance of the sensitive film decreases, the first and second bus electrodes facing each other without sandwiching the first and second sensor electrodes may easily become conductive, which may make it difficult to identify the hydrogen leakage point. For example, in FIG. 3, the interval between the first and second bus electrodes facing each other without sandwiching the first and second sensor electrodes is indicated by g.

[0055] The interval between adjacent first bus electrodes and the interval between adjacent second bus electrodes may be any interval that does not allow the change in the electrical resistance of the sensitive film to be detected. The interval may be, for example, 10 mm or more, and may be 50 mm or more. The interval may be, for example, 100 mm or less, and may be 70 mm or less. That is, the interval may be, for example, 10 mm or more and 100 mm or less, and 50 mm or more and 70 mm or less. If the interval is too small, when the reduction reaction of the tungsten oxide occurs and the electrical resistance of the sensitive film decreases, the adjacent first bus electrodes or the adjacent second bus electrodes tend to be conductive with each other, which may make it difficult to identify the hydrogen leakage point. For example, in FIG. 3, the interval between adjacent first bus electrodes is indicated by h1, and the interval 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 usually 1. 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 2. For example, in FIG. 6, hydrogen sensor 1 has two first bus electrodes 5a, 5b and two second bus electrodes 6a, 6b, where 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 similar to 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 similar to 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 of the catalyst include precious metals such as palladium, platinum, iridium, etc. The catalyst may be used alone or in combination of two or more kinds.

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

[0065] The position of the sensitive film is not particularly limited as long as the sensitive film 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 a thickness that allows detection of 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 a thickness that can detect the change in the electrical resistance of the tungsten oxide layer, and is, for example, 100 nm to 3000 nm. Also, 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 the method of forming the sensitive film by the sol-gel method, refer 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 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 a change 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 one that can detect a change in electrical resistance, and may be, for example, one having an IC chip that detects a change in electrical resistance. An open-short type IC chip may be used as the IC chip. The open-short type is an IC chip that detects a change in electrical resistance by setting a flag to "1" when the resistance between terminals is equal to or lower than a set value, and setting the flag to "0" when the resistance is equal to or higher than another set value. Alternatively, a capacitive type IC chip may be used as the IC chip. The capacitive type is typically an IC chip that detects an impedance change when the antenna is detuned when water droplets or the like come into contact with the antenna. 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, and the impedance change is detected. Among them, an open-short type IC chip is preferable. An example of an open-short type IC chip is the UCODE G2iM+ by NXP.

[0072] Specifically, an IC tag having the above IC chip and antenna is used as the control unit. The IC tag is also called an RF tag, an RFID tag, an electronic tag, a wireless tag, etc. Any IC tag having the above IC chip and an antenna can be used, and a general IC tag can be used. If it is an IC tag, it can detect hydrogen gas by utilizing RFID.

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

[0074] An example of the operation 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 in which hydrogen does not exist, the sensitive film has 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 if power is supplied to the IC tag from an external device, no current flows through the first sensor electrode and the second sensor electrode through the sensitive film. On the other hand, in an atmosphere in which hydrogen exists, the above-mentioned reduction reaction of tungsten oxide occurs, and the sensitive film has a lowered electrical resistance and becomes conductive. At this time, the first sensor electrode and the second sensor electrode are short-circuited and in a conductive state. Therefore, when power is supplied to the IC tag from an external device, a current flows through the first sensor electrode and the second sensor electrode through the sensitive film. The IC chip measures the value of the electrical resistance, detects information from the value of the electrical resistance, and transmits a signal according to the information to the external device. The external device detects hydrogen leakage based on the above information and identifies the hydrogen leakage location.

[0075] There is at least one control unit. There may be one control unit, or there may be two control units, 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 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 controllers, a first controller and a second controller. 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 difference between the electrical resistance measured by the first controller and the electrical resistance measured by the second controller can be used to identify the position where the sensitive film reacts with hydrogen and the electrical resistance is reduced. 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 to reduce the electrical load on the control unit. This can further increase the 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, not less than 10 μm and not more than 2 mm.

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

[0081] The hydrogen sensor of this embodiment can be made large 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 the hydrogen sensor of this embodiment. As shown in FIG. 7, the hydrogen sensor 1 has a substrate 2, a sensitive film 3 that is disposed on the first surface of the substrate 2 and contains 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 that are disposed on the first surface of the substrate 2 and connected to the control unit 4, a plurality of first sensor electrodes 7 that are 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 that are 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 that allow the change in electrical resistance of the sensitive film 3 to be detected. In FIG. 7, the first sensor electrode 7 and the second sensor electrode 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] As described above, the hydrogen sensor shown in Fig. 7 can detect hydrogen gas by detecting changes in electrical resistance with the control unit. Moreover, the hydrogen sensor shown in Fig. 7 has one control unit, and by measuring electrical resistance with the 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] In the hydrogen sensor shown in Fig. 8, as described above, hydrogen gas can be detected by detecting the change in electrical resistance with the control unit. Also, in the hydrogen sensor shown in Fig. 8, the control unit has two 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 leakage can be detected at low cost even over a wide area, and the hydrogen leakage location can be identified. Furthermore, in this embodiment, the lengths of the first bus electrode and the second bus electrode can be shortened compared to the first embodiment, so that an increase in electrical resistance due to the lengths of the first bus electrode and the second bus electrode can be suppressed. 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] Each component of the hydrogen sensor of this embodiment will be described below.

[0090] 1. First sensor electrode and second sensor electrode In this embodiment, the first sensor electrodes and the 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 the change in the electrical resistance of the sensitive film to be detected. 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 interval between the first sensor electrode and the second sensor electrode means the distance from the end of the first sensor electrode to the end of the second sensor electrode adjacent to each other. For example, in FIG. 7, the interval between the first sensor electrode and the second sensor electrode is indicated as d1.

[0093] The width of the first sensor electrode and the width of the second sensor electrode may be any width that can detect the change in the electrical resistance of the sensitive film. The width may be, for example, 100 μm or more, and 500 μm or more. The width may be, for example, 10 mm or less, and 5 mm or less. That is, the width may be, for example, 100 μm or more and 10 mm or less, and 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 may be any length that allows the change in the electrical resistance of the sensitive film to be detected. The length may be, for example, 10 mm or more, and may be 50 mm or more. The length may be, for example, 500 mm or less, and may be 100 mm or less. That is, the 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. 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 of the first sensor electrode and the second sensor electrode may be any length that allows detection of a change in the electrical resistance of the sensitive film. The overlap length may be, for example, 9 mm or more, and may be 45 mm or more. The overlap length may be, for example, 450 mm or less, and may be 90 mm or less. That is, the overlap 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 overlap length of 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 appropriately set depending on the size of the hydrogen sensor, the arrangement of the first bus electrodes, and the arrangement of the second bus electrodes, etc.

[0097] The shape of the first sensor electrode and the second sensor electrode is not particularly limited, and may be, for example, a straight line, a bent line, or a curved line.

[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 interval between the first bus electrode and the second bus electrode may be any interval that allows the first sensor electrode and the second sensor electrode to be arranged. The interval may be, for example, 11 mm or more, and may be 55 mm or more. The interval may be, for example, 550 mm or less, and may be 110 mm or less. That is, the interval 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 interval 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 electrodes and the second bus electrodes may be the same or different as long as they are a pair of electrodes. For example, in Fig. 7, the number of the first bus electrodes 5 is four and the number of the second bus electrodes 6 is five, so that 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 similar to 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 similar to 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 a change 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 control units, 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 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 film, 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, 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 perpendicular to the first direction, the control unit has 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 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] 9 is a schematic plan view showing an example of the hydrogen sensor of this embodiment. As shown in FIG. 9, the hydrogen sensor 1 has a substrate 2, a sensitive film 3 arranged on the first surface of the substrate 2, 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 arranged 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 arranged 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 arranged 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 that allow the change in electrical resistance of the sensitive film 3 to be detected. In FIG. 9, the first sensor electrode 7 and the second sensor electrode 8 are a pair 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 a 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] In the hydrogen sensor shown in Fig. 9, as described above, hydrogen gas can be detected by detecting a change in electrical resistance with 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, and thus it is possible to identify, among the intersections of the first bus electrode and the second bus electrode, an intersection of the first bus electrode and the second bus electrode where the electrical resistance has decreased. Therefore, the intersection of the first bus electrode and the second bus electrode where the electrical resistance has decreased can be identified as the position where the electrical resistance has decreased due to the reaction of the sensitive film with hydrogen.

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

[0117] In addition, in this embodiment, since it is not necessary to arrange the first bus electrode and the second bus electrode in a line that can be drawn in one stroke, the risk of disconnection can be reduced. Also, as shown in Fig. 9, the area of ​​the portion 10C where the first sensor electrode 7 and the second sensor electrode 8 overlap can be made constant, so that the variation in the signal is reduced and the detection sensitivity is improved.

[0118] Below, the hydrogen sensor of this embodiment will be described in detail with respect to each component.

[0119] 1. First sensor electrode and second sensor electrode In this embodiment, the first sensor electrodes and the 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-teeth electrodes.

[0121] The distance between the first sensor electrode and the second sensor electrode may be any distance that allows the change in the electrical resistance of the sensitive film to be detected. 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 interval between the first sensor electrode and the second sensor electrode means the distance from the end of the first sensor electrode to the end of the second sensor electrode adjacent to each other. For example, in Fig. 9, the interval between the first sensor electrode and the second sensor electrode is indicated as d1.

[0123] The width of the first sensor electrode and the width of the second sensor electrode may be any width that can detect the change in the electrical resistance of the sensitive film. The width may be, for example, 100 μm or more, and 500 μm or more. The width may be, for example, 10 mm or less, and 5 mm or less. That is, the width may be, for example, 100 μm or more and 10 mm or less, and 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 allows the change in the electrical resistance of the sensitive film to be detected. The length may be, for example, 10 mm or more, and may be 50 mm or more. The length may be, for example, 500 mm or less, and may be 100 mm or less. That is, the 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 overlap length of the first sensor electrode and the second sensor electrode may be any length that allows the change in the electrical resistance of the sensitive film to be detected. The overlap length may be, for example, 9 mm or more, and may be 45 mm or more. The overlap length may be, for example, 450 mm or less, and may be 90 mm or less. That is, the overlap 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 overlap length of 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 appropriately set depending on the size of the hydrogen sensor, the arrangement of the first bus electrodes, and the arrangement of the second bus electrodes, etc.

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

[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 interval between adjacent first bus electrodes and the interval between adjacent second bus electrodes may be any interval that allows the arrangement of the first sensor electrodes and the second sensor electrodes. The interval may be, for example, 11 mm or more and 55 mm or more. The interval may be, for example, 550 mm or less and 110 mm or less. That is, the interval may be, for example, 11 mm or more and 550 mm or less and 55 mm or more and 110 mm or less. For example, in FIG. 9, the interval between adjacent first bus electrodes is indicated by k1, and the interval 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 similar to 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 similar to 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 the sensitive film is arranged 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 arranged in this order 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 on the first surface of the substrate, the first sensor electrode, the sensitive film, and the second sensor electrode may be arranged 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 arranged 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 a change 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 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. The control unit may also have 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. The control unit may also have 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. The control unit may also have 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 has a third control unit 4c connected to one end of the plurality of first bus electrodes 5, a fourth control unit 4d connected to one end of the 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 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. 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 and second bus electrodes in the region where the first and second bus electrodes intersect.

[0143] The material for 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 is thick enough to insulate the first bus electrode and the second bus electrode, and is, for example, not less than 0.1 μm and not more than 2 μm.

[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 deposition method, and a printing method. Examples of the method for forming the insulating film include a vacuum 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 in the present disclosure uses the hydrogen sensor described above.

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

[0148] Fig. 13 is a schematic diagram showing another example of a hydrogen detection system according to the present disclosure. In Fig. 12, a 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 sensors 1 are attached to a hydrogen pipeline 30 installed underground. The RFID reader / writer 21 and the antenna 22 are installed on a mobile object 23 and are 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 in 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 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 either 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, a trace inspection can be performed, which makes the 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 allowing 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 in the present disclosure, and FIG. 15 is a schematic plan view showing an example of a 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 has a substrate 2, a sensitive film 3 that is disposed on the first surface of the substrate 2 and contains a catalyst that dissociates hydrogen molecules and tungsten oxide, a bus electrode 41 that is disposed on the first surface of the substrate 2 and is disposed in a meandering line, and a plurality of first sensor electrodes 7 and a plurality of second sensor electrodes 8 that are disposed on the first surface of the substrate 2 in contact with the sensitive film 3 and connected to the bus electrode 41. The first sensor electrodes 7 and the second sensor electrodes 8 are alternately disposed at intervals that allow a change in the electrical resistance of the sensitive film 3 to be detected.

[0155] The hydrogen sensor sheet according to the present disclosure is used for manufacturing the above-mentioned hydrogen sensor. The hydrogen sensor sheet according to the present disclosure can be manufactured by a roll-to-roll method, so that hydrogen sensors can be mass-produced efficiently.

[0156] The bus electrode, first sensor electrode, second sensor electrode, and sensitive membrane in the hydrogen sensor sheet of the present disclosure are similar to 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-mentioned 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 to which the control unit is to be connected is cut. Then, the control unit is placed.

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

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

[0160] The hydrogen sensor shown in Figure 4 was fabricated. The first bus electrode, the second bus electrode, the first sensor electrode, and the second sensor electrode were formed by printing 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 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 in between was 90 mm, the interval 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 interval h1 between adjacent first bus electrodes and the interval h2 between adjacent second bus electrodes were 10 mm. 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 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] It was confirmed that radio waves could be read and transmitted to the hydrogen sensor using an RFID reader / writer, and that the reflected and transmitted radio waves could be detected. In addition, when radio waves were transmitted in the same manner as above while the hydrogen sensor was exposed to hydrogen gas, 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] In addition, the resistance value measured by the first control unit was R1, the resistance value measured by the second control unit was R2, and R1 was divided by the total resistance value (R1+R2), and the coefficient was multiplied by the total length of the first bus electrode or the second bus electrode to identify the leak location from the first control unit. Although the resistance value changes depending on the hydrogen concentration, the above method made it possible to accurately identify the leak location regardless of the hydrogen concentration.

[0163] In this 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 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 disposed 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 are 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 meandering line. [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 perpendicular to the first direction, the control unit includes a third control unit connected to one ends of the first bus electrodes and a fourth control unit connected to one ends of the 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 for dissociating hydrogen molecules and tungsten oxide; A bus electrode arranged on a first surface of the substrate and arranged in a meandering line shape; a plurality of first sensor electrodes and a plurality of second sensor electrodes are disposed 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 an interval that allows detection of a change 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 disposed 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 electrode and the second sensor electrode are alternately arranged at an interval capable of detecting a change in the electrical resistance of the sensitive film, 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, one end of the first bus electrode and one end of the second bus electrode are connected to the control unit, A hydrogen sensor, 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.

2. 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 disposed 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 electrode and the second sensor electrode are alternately arranged at an interval capable of detecting a change in the electrical resistance of the sensitive film, 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, one end of the first bus electrode and one end of the second bus electrode are connected to the control unit, A hydrogen sensor, wherein the first bus electrode and the second bus electrode are arranged in a serpentine line.

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 disposed 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 electrode and the second sensor electrode are alternately arranged at an interval capable of detecting a change in the electrical resistance of the sensitive film, 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 first bus electrodes and a fourth control unit connected to one ends of the second bus electrodes, A hydrogen sensor, 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.

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

5. 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 for dissociating hydrogen molecules and tungsten oxide; a bus electrode disposed 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 are disposed 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 electrodes and the second sensor electrodes are alternately arranged at intervals that enable detection of changes in the electrical resistance of the sensitive film.

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