Environmental diagnostic sensor, environmental diagnostic sensor array, and environmental diagnostic device

Abstract

The environmental diagnostic sensor (11) includes a pair of electrodes (1), a resistive film (2) disposed between the pair of electrodes, a protective film (3) disposed on the resistive film, and a thin metal film (4) that is corroded by a corrosive gas. The resistive film and the thin metal film are electrically connected in parallel to each other between the pair of electrodes. The thin metal film has a first portion (41) disposed on the resistive film via the protective film.

Description

[Technical field]

[0001] The present disclosure relates to an environmental diagnostic sensor, an environmental diagnostic sensor array, and an environmental diagnostic device. [Background technology]

[0002] Electrical devices are installed and used in a variety of environments, but if corrosive gases are present in the environment in which the electrical device is used, the circuit boards and other components contained in the electrical device may become damaged over time due to corrosion (e.g., metal wiring may break).In order to prevent such problems from occurring, environmental diagnostic sensors have been proposed to diagnose the degree of corrosion of electrical devices in the usage environment, or the corrosivity corresponding to the degree of corrosion of electrical devices in the usage environment.

[0003] For example, in the detection device described in JP 2014-153089 A (Patent Document 1), a plurality of detection circuit lines are provided, each of which is formed by connecting a metal thin film wiring and a fixed resistor in series, and the plurality of detection circuit lines are connected in parallel. The metal material or film thickness, etc., of each of the metal thin film wirings of the plurality of detection circuit lines are different from each other. According to the above detection device, in the usage environment of the electrical device, the time until each metal thin film wiring is corroded and disconnected is calculated based on the change over time in the combined resistance of the plurality of detection circuit lines, and the corrosiveness in the usage environment can be clarified based on the corrosion rate of each metal thin film wiring calculated from the result. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2014-153089 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the above-mentioned detection device, each metal thin film wiring is arranged next to the fixed resistor on the insulating substrate so as to be electrically connected in series with the fixed resistor, and since each of the metal thin film wiring and the fixed resistor requires its own area, it is difficult to miniaturize the detection device.

[0006] A primary object of the present disclosure is to enable miniaturization of an environmental diagnostic sensor. [Means for solving the problem]

[0007] The environmental diagnostic sensor according to the present disclosure includes a pair of electrodes, a resistive film disposed between the pair of electrodes, a protective film disposed on the resistive film, and a thin metal film corroded by a corrosive gas. The resistive film and the thin metal film are electrically connected in parallel to each other between the pair of electrodes. The thin metal film has a first portion disposed on the resistive film via the protective film. Effect of the Invention

[0008] According to the present disclosure, the environmental diagnostic sensor can be miniaturized. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram illustrating an example of an environment diagnosis device according to a first embodiment. [Diagram 2] 1 is a cross-sectional view showing an example of an environment diagnostic sensor according to a first embodiment. [Diagram 3] 1 is a plan view showing an example of an environment diagnostic sensor according to a first embodiment. [Figure 4] 5 is a diagram for explaining an example of a change over time in combined resistance of the environment diagnostic sensor according to the first embodiment. FIG. [Diagram 5] FIG. 11 is a diagram illustrating an example of an environment diagnosis device according to a second embodiment. [Figure 6] FIG. 11 is a cross-sectional view showing an example of an environment diagnostic sensor array according to a second embodiment. [Figure 7] FIG. 11 is a diagram for explaining an example of a change over time in the combined resistance of the environment diagnostic sensor array according to the second embodiment. [Figure 8] FIG. 11 is a cross-sectional view showing an example of an environment diagnostic sensor array according to a third embodiment. [Figure 9] FIG. 11 is a diagram for explaining an example of a change over time in the combined resistance of the environment diagnostic sensor array according to the third embodiment. [Figure 10] FIG. 11 is a diagram for explaining another example of the change over time in the combined resistance of the environmental diagnostic sensor array according to the third embodiment. [Figure 11] FIG. 11 is a cross-sectional view showing an example of an environment diagnostic sensor array according to a fourth embodiment. [Figure 12] FIG. 13 is a diagram for explaining an example of a change over time in the combined resistance of the environment diagnostic sensor array according to the fourth embodiment. [Figure 13] FIG. 13 is a diagram for explaining another example of the change over time in the combined resistance of the environmental diagnostic sensor array according to the fourth embodiment. [Figure 14] FIG. 13 is a cross-sectional view showing an example of an environment diagnostic sensor array according to a fifth embodiment. [Figure 15] FIG. 13 is a plan view showing an example of an environment diagnostic sensor array according to a fifth embodiment. [Figure 16] FIG. 13 is a perspective view showing an example of an environment diagnostic sensor array according to a sixth embodiment. [Figure 17] FIG. 13 is a plan view showing an example of an environment diagnostic sensor array according to a sixth embodiment. [Figure 18] FIG. 13 is a cross-sectional view showing an example of an environment diagnostic sensor array according to a seventh embodiment. [Figure 19] 1 is a graph showing how the rate of change over time (corrosion rate) of the corrosion defect thickness (amount of corrosion) of a metal thin film changes depending on the environment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following, the same or corresponding parts are denoted by the same reference characters, and overlapping descriptions will not be repeated.

[0011] The environmental diagnosis sensor according to the present embodiment is a sensor for diagnosing the corrosiveness of the environment in which an electric device is used. The environmental diagnosis sensor according to the present embodiment is included in an electric device together with the electric device body, for example, and is used simultaneously with the electric device body to estimate the degree of corrosion of the electric device body. The environmental diagnosis sensor according to the present embodiment is mounted on, for example, a circuit board of the electric device body. The type of electric device is not particularly limited. The electric device is any electric device used in an environment where corrosive gas may be present. The environmental diagnosis sensor according to the present embodiment may be used separately from the electric device.

[0012] In this embodiment, corrosive gas is a general term for gas that corrodes metal material parts in electrical equipment. Corrosive gases include, for example, sulfur-based gases, chlorine-based gases, and nitrogen oxides. Sulfur-based gases include hydrogen sulfide (H2S), sulfur dioxide (SO2), and sulfur flowers (S8). Chlorine-based gases include chlorine gas (Cl2). Nitrogen oxides (NO x ) includes, for example, nitrogen dioxide (NO2). In this embodiment, corrosion refers to the generation of corrosion products and the eventual loss of the metal material part. In the following, the term "initial" is used to indicate the state before the environmental diagnosis sensor is exposed to the corrosive gas.

[0013] Embodiment 1 <Environmental diagnostic device configuration> As shown in FIG. 1, the environment diagnostic device 101 according to the first embodiment includes, for example, an environment diagnostic sensor 11, a power source 20, an electric circuit including a resistance measuring device 30, and an analysis device .

[0014] The environmental diagnostic sensor 11 includes a pair of electrodes 1, a resistive film 2, and a thin metal film 4. The resistive film 2 is, for example, a resistive film of a fixed resistor 10. The resistive film 2 and the thin metal film 4 are electrically connected in parallel to each other between the pair of electrodes 1. The environmental diagnostic sensor 11 is mounted on, for example, a circuit board of an electric device body. An example of the structure of the environmental diagnostic sensor 11 will be described later.

[0015] The power source 20 applies a voltage between the pair of electrodes 1 of the environmental diagnosis sensor 11. The power source 20 is included in, for example, the main body of the electric device. Note that the power source 20 may be a power source independent of the main body of the electric device. The power source 20 may be a battery.

[0016] The resistance measuring device 30 measures the combined resistance of the resistive film 2 and the metal thin film 4 of the environmental diagnostic sensor 11, and outputs the measurement result to the analyzing device 40. The resistance measuring device 30 includes, for example, a voltmeter 301 and an ammeter 302. The voltmeter 301 measures the voltage applied between the pair of electrodes 1 of the environmental diagnostic sensor 11, and outputs the measurement result to the analyzing device 40. The ammeter 302 measures the current flowing through the environmental diagnostic sensor 11, and outputs the measurement result to the analyzing device 40.

[0017] The analysis device 40 includes, for example, a microprocessor. The analysis device 40 identifies the degree of corrosion of the metal thin film 4 from the resistance value measured by the resistance measuring device 30. Furthermore, the analysis device 40 identifies the type of corrosive gas present in the environment based on the resistance value measured by the resistance measuring device 30 and corrosion resistance information described below. The analysis device 40 outputs the analysis result to an alarm device or the like.

[0018] <Environmental diagnostic sensor configuration> As shown in FIG. 2 and FIG. 3, the environment diagnostic sensor 11 includes a pair of electrodes 1, a resistive film 2, a protective film 3, a metal thin film 4, and an insulating substrate 5. The resistive film 2 is a resistive film having a thickness of 100 nm.

[0019] The insulating substrate 5 is a substrate having electrical insulation properties. For example, aluminum oxide (Al2O3), glass (SiO2), or silicon wafer (Si) can be used as the material of the insulating substrate 5. The insulating substrate 5 has, for example, a rectangular parallelepiped shape. The insulating substrate 5 has an upper surface (first surface), a lower surface (second surface), a first side surface, and a second side surface. The upper surface and the lower surface of the insulating substrate 5 extend along a first direction DR1 and a second direction perpendicular to the first direction DR1. The first side surface and the second side surface face in opposite directions to each other in the first direction DR1. The insulating substrate 5 further has a third side surface and a fourth side surface. Each of the third side surface and the fourth side surface extends between the first side surface and the second side surface. The third side surface and the fourth side surface face in opposite directions to each other in the second direction.

[0020] The pair of electrodes 1 are arranged on the surface of the insulating substrate 5 with a gap between them. Each of the pair of electrodes 1 has one end arranged on the upper surface of the insulating substrate 5 and the other end arranged on the lower surface of the insulating substrate 5. The ends of the pair of electrodes 1 are arranged on the upper surface of the insulating substrate 5 with a gap between them. The other ends of the pair of electrodes 1 are arranged on the lower surface of the insulating substrate 5 with a gap between them. One of the pair of electrodes 1 covers a first side surface of the insulating substrate 5 and a part of the first side surface of each of the upper surface and the lower surface. The other of the pair of electrodes 1 covers a second side surface of the insulating substrate 5 and a part of the second side surface of each of the upper surface and the lower surface. The part of each of the pair of electrodes 1 arranged on the lower surface of the insulating substrate 5 functions as a so-called back electrode that is electrically connected to a circuit board (for example, a circuit board of an electric device body) on which the environmental diagnostic sensor 11 is mounted.

[0021] Each of the pair of electrodes 1 includes, for example, an internal electrode 6, an intermediate electrode 7, and an external electrode 8. The internal electrode 6, intermediate electrode 7, and external electrode 8 are layered in this order from the surface side of the insulating substrate 5 in a direction perpendicular to the surface of the insulating substrate 5. The internal electrode 6 extends, for example, on the upper surface of the insulating substrate 5 further inward than the intermediate electrode 7 and the external electrode 8. On the upper surface of the insulating substrate 5, one ends of the intermediate electrode 7 and the external electrode 8 are disposed outward than one end of the internal electrode 6.

[0022] The internal electrode 6 is covered by an intermediate electrode 7 or a protective film 3, except for the other end disposed on the lower surface of the insulating substrate 5. The intermediate electrode 7 is covered by an external electrode 8. The external electrode 8 is exposed on the lower surface, first side surface, and second side surface of the insulating substrate 5. The external electrode 8 is covered by a metal thin film 4 on the upper surface of the insulating substrate 5.

[0023] The material constituting the internal electrodes 6 includes, for example, silver (Ag). The material constituting the intermediate electrodes 7 includes, for example, nickel (Ni). The material constituting the external electrodes 8 includes, for example, tin (Sn).

[0024] The resistive film 2 is disposed between a pair of electrodes 1 on the upper surface of the insulating substrate 5. The resistive film 2 electrically connects the above-mentioned one end of each of the pair of electrodes 1. The resistive film 2 is in contact with, for example, only each of the internal electrodes 6 of the pair of electrodes 1. The resistance value R of the resistive film 2 is R is the initial resistance R of the metal thin film 4 before it is exposed to the corrosive gas. M1 The material constituting the resistive film 2 includes, for example, an oxide semiconductor. The material constituting the resistive film 2 includes, for example, ruthenium oxide (RuO2). Note that the material constituting the resistive film 2 is not limited to the above materials.

[0025] The protective film 3 is disposed on the resistive film 2. The protective film 3 covers, for example, the resistive film 2. The protective film 3 covers, for example, the resistive film 2 and one end of each internal electrode 6 of the pair of electrodes 1 connected to the resistive film 2. The protective film 3 is disposed, for example, across each intermediate electrode 7 of the pair of electrodes 1. The protective film 3 is more resistant to corrosive gas than the resistive film 2. The material constituting the protective film 3 and the thickness of the protective film 3 can be arbitrarily set as long as the corrosion of the resistive film 2 can be suppressed during the time from when the environmental diagnostic device 101 is exposed to the corrosive gas until the metal thin film 4 is broken due to corrosion. The material constituting the protective film 3 includes, for example, an epoxy resin. The protective film 3 has, for example, a central portion 31 and a pair of outer edge portions 32 disposed so as to sandwich the central portion 31 in the first direction DR1. The thickness of the central portion 31 is constant. One end of each external electrode 8 of the pair of electrodes 1 is formed, for example, on the outer edge portion of the protective film 3.

[0026] The metal thin film 4 is exposed to a corrosive gas and corrodes due to the corrosive gas. The metal thin film 4 covers parts of the pair of electrodes 1, the resistive film 2, and the protective film 3 on the upper surface of the insulating substrate 5. The metal thin film 4 has a first portion 41 disposed on the resistive film 2 via the protective film 3, and a pair of second portions 42 disposed on the pair of electrodes 1. The first portion 41 is continuous with the pair of second portions 42.

[0027] The material constituting the thin metal film 4 is selected according to the corrosive gas to be detected by the environmental diagnosis device 101, i.e., the corrosive gas expected to be present in the environment in which the electrical device is used. For example, when the corrosive gas to be detected is sulfur oxide or chlorine gas, the material constituting the thin metal film 4 preferably contains Ag. When the corrosive gas to be detected is hydrogen sulfide, sulfur dioxide, or nitrogen dioxide, the material constituting the thin metal film 4 preferably contains Cu.

[0028] The thickness of the metal thin film 4 can be set arbitrarily. For example, the thickness of the metal thin film 4 corresponds to the corrosion defect thickness expected after a predetermined time has elapsed based on the expected degree of corrosion of the electrical device in the usage environment or the corrosiveness of the usage environment of the electrical device. The details will be described later.

[0029] 4, in the environment diagnostic device 101, the combined resistance value of the resistive film 2 and the thin metal film 4 changes as the corrosion of the thin metal film 4 progresses. The initial combined resistance value R C1 is the resistance value R of resistive film 2 R , the initial resistance value R of the metal thin film 4 M1 Then, R M1 ×R R / (R M1 +R R The initial resistance value R of the metal thin film 4 before the environmental diagnostic device 101 is exposed to the corrosive gas is M1 is the resistance value R of resistive film 2 R Therefore, before the environmental diagnostic device 101 is exposed to the corrosive gas, the current mainly flows through the thin metal film 4.

[0030] As the corrosion of the metal thin film 4 by the corrosive gas progresses, the resistance value of the metal thin film 4 decreases to the initial resistance value R M This is because a part of the metal thin film 4 becomes a corrosion product or is lost. The resistance value R of the metal thin film 4 after the metal thin film 4 located between the pair of electrodes 1 is broken is M2 is the initial resistance value R of the metal thin film 4 M1 On the other hand, since the resistive film 2 covered by the protective film 3 is not exposed to the corrosive gas, the resistance value R R does not change. The resistance value R of the metal thin film 4 M 2 is the resistance R R For example, the resistance value R R Therefore, the resistance value R of the metal thin film 4 M2 is the resistance value R of resistive film 2 RTherefore, the combined resistance R of the resistive film 2 and the metal thin film 4 after the metal thin film 4 is broken is C2 is R R Equivalent to (R C2 ≒R R ) can be regarded as

[0031] In this way, the combined resistance value of the resistive film 2 and the thin metal film 4 is significantly different before and after at least the thin metal film 4 is broken. 12 By detecting this, it is possible to detect that the thin metal film 4 has been broken.

[0032] The effects of the environmental diagnostic sensor 11 and the environmental diagnostic device 101 will be described below in comparison with a comparative example. In the environmental diagnostic sensor according to the comparative example, the metal thin film does not have the first portion 41 and is electrically connected in series to the resistive film. In this comparative example, the metal thin film and the resistive film each require their own dedicated area, making it difficult to reduce the size.

[0033] In contrast, the environmental diagnostic sensor 11 has the first portion 41 in which the thin metal film 4 is disposed on the resistive film 2 via the protective film 3, and therefore can be made smaller than the comparative example.

[0034] Furthermore, in the above comparative example, a verification test is required at the time of design so that the resistive film does not corrode and break before the thin metal film.

[0035] On the other hand, in the environment diagnostic sensor 11, since the resistive film 2 is covered with the protective film 3 and the metal thin film 4, the metal thin film 4 inevitably corrodes and breaks before the resistive film 2, and the resistive film 2 is prevented from corroding and breaking before the metal thin film 4. Therefore, the above-mentioned verification test is not necessary in the environment diagnostic sensor 11. Therefore, the manufacturing costs of the environment diagnostic sensor 11 and the environment diagnostic device 101 can be reduced compared to the comparative example.

[0036] <Modification> The protective film 3 may be disposed at least between the resistive film 2 and the first portion 41 of the thin metal film 4, and may not cover the resistive film 2. The resistive film 2 may have a surface exposed from the protective film 3 and exposed to the corrosive gas. Such a resistive film 2 may be made of a material that is more resistant to the corrosive gas than the thin metal film 4. Such an environmental diagnostic sensor may also be made smaller than the comparative example.

[0037] Embodiment 2 5 and 6, unless otherwise specified, the environment evaluation device 102 according to the embodiment 2 has the same configuration and effects as those of the above-mentioned embodiment 1. Therefore, the same components as those of the above-mentioned embodiment 1 are denoted by the same reference numerals, and the description thereof will not be repeated.

[0038] As shown in FIGS. 5 and 6, the environment diagnostic device 102 according to the second embodiment includes an environment diagnostic sensor array 12 including a plurality of environment diagnostic sensors.

[0039] The environment diagnostic sensor array 12 includes a first environment diagnostic sensor 11A and a second environment diagnostic sensor 11B. Each of the first environment diagnostic sensor 11A and the second environment diagnostic sensor 11B has the same configuration and effects as the environment diagnostic sensor 11 in the first embodiment.

[0040] 5 and 6, the first environmental diagnostic sensor 11A is electrically connected in series with the second environmental diagnostic sensor 11B. The resistive film 2 and the thin metal film 4 of the first environmental diagnostic sensor 11A are electrically connected in series with the resistive film 2 and the thin metal film 4 of the second environmental diagnostic sensor 11B.

[0041] As shown in Fig. 6, the initial thickness TB of the metal thin film 4B of the second environment diagnostic sensor 11B before exposure to the corrosive gas is thicker than the initial thickness TA of the metal thin film 4A of the first environment diagnostic sensor 11A before exposure to the corrosive gas. The material constituting the metal thin film 4B of the second environment diagnostic sensor 11B is the same as the material constituting the metal thin film 4A of the first environment diagnostic sensor 11A. Only the initial thickness of the metal thin film is different between the first environment diagnostic sensor 11A and the second environment diagnostic sensor 11B. The initial resistance value of the metal thin film 4 of the second environment diagnostic sensor 11B before exposure to the corrosive gas is smaller than the initial resistance value of the metal thin film 4 of the first environment diagnostic sensor 11A before exposure to the corrosive gas.

[0042] In the first environmental diagnostic sensor 11A, the initial resistance value of the metal thin film 4A before exposure to the corrosive gas is smaller than the resistance value of the resistive film 2A. In the second environmental diagnostic sensor 11B, the initial resistance value of the metal thin film 4B before exposure to the corrosive gas is smaller than the resistance value of the resistive film 2B. The resistance value of the resistive film 2A is, for example, the same as the resistance value of the resistive film 2B. The film thickness of the resistive film 2A is, for example, the same as the film thickness of the resistive film 2B. The material constituting the resistive film 2A is, for example, the same as the material constituting the resistive film 2B. That is, in the second environmental diagnostic sensor 11B, the initial resistance value of the metal thin film 4 before exposure to the corrosive gas is significantly smaller than the resistance value of the resistive film 2B.

[0043] One of a pair of electrodes 1 of the first environmental diagnostic sensor 11A is electrically connected in series with one of a pair of electrodes 1 of the second environmental diagnostic sensor 11B via a wiring 62. The first environmental diagnostic sensor 11A and the second environmental diagnostic sensor 11B are mounted on, for example, a circuit board 60. The pair of electrodes 1 of each of the first environmental diagnostic sensor 11A and the second environmental diagnostic sensor 11B are mounted on and electrically connected to the circuit board 60 by a bonding member 63. The bonding member 63 is, for example, solder.

[0044] The wiring 62 is formed as a wiring pattern on the substrate 61 of the circuit board 60, for example. The wiring 62 extends along the first direction DR1, for example. The first environmental diagnostic sensor 11A and the second environmental diagnostic sensor 11B are arranged side by side at intervals in the first direction DR1, for example. The material constituting the wiring 62 includes, for example, aluminum (Al).

[0045] The wiring 62 may have any shape in plan view. The relative positional relationship between the first environmental diagnostic sensor 11A and the second environmental diagnostic sensor 11B in plan view may be set arbitrarily. The material constituting the wiring 62 may include stainless steel.

[0046] The upper surface of the thin metal film 4B of the second environmental diagnostic sensor 11B protrudes upward, for example, from the upper surface of the thin metal film 4A of the first environmental diagnostic sensor 11A. The upper surface of the thin metal film 4B of the second environmental diagnostic sensor 11B may be disposed on the same plane as the upper surface of the thin metal film 4A of the first environmental diagnostic sensor 11A. In this case, it is only necessary that the upper surface of the wiring pattern in the region on the circuit board 60 where the second environmental diagnostic sensor 11B is mounted is recessed with respect to the upper surface of the wiring pattern in the region on which the first environmental diagnostic sensor 11A is mounted.

[0047] As shown in FIG. 7, in the environment diagnostic device 102, the combined resistance value of the environment diagnostic sensor array 12 changes with the progress of corrosion of the metal thin films 4A and 4B. Since the initial film thickness TA of the metal thin film 4A of the first environment diagnostic sensor 11A is thinner than the initial film thickness TB of the metal thin film 4B of the second environment diagnostic sensor 11B, the metal thin film 4A is broken due to corrosion before the metal thin film 4B. When the metal thin film 4A is broken, the combined resistance value of the resistive film 2 and the metal thin film 4A in the first environment diagnostic sensor 11A changes significantly, and the combined resistance value of the environment diagnostic sensor array 12 also changes in the same manner. After that, when the metal thin film 4B is broken, the combined resistance value of the resistive film 2 and the metal thin film 4B in the second environment diagnostic sensor 11B changes significantly, and the combined resistance value of the environment diagnostic sensor array 12 also changes in the same manner. The amount of change R of the combined resistance value of the resistive film 2 and the metal thin film 4B in the second environment diagnostic sensor 11B is Bis the change amount R of the combined resistance value of the resistive film 2 and the thin metal film 4A in the first environment diagnostic sensor 11A. A Therefore, according to the environment diagnostic device 102, the change amount R A By detecting the disconnection of the metal thin film 4A, the change amount R of the combined resistance value of the environmental diagnostic sensor array 12 is detected. B By detecting these, a break in the thin metal film 4B can be detected.

[0048] Embodiment 3 8, unless otherwise specified, the environment diagnosis device 103 according to the embodiment 3 has the same configuration and effects as those of the above-mentioned embodiment 2. Therefore, the same components as those of the above-mentioned embodiment 2 are denoted by the same reference numerals, and the description thereof will not be repeated.

[0049] 8, the environment diagnostic device 103 according to the third embodiment includes an environment diagnostic sensor array 13. The environment diagnostic sensor array 13 includes a third environment diagnostic sensor 11C and a fourth environment diagnostic sensor 11D. Each of the third environment diagnostic sensor 11C and the fourth environment diagnostic sensor 11D has the same configuration and effects as the environment diagnostic sensor 11 according to the first embodiment.

[0050] 8, the third environment diagnostic sensor 11C is electrically connected in series with the fourth environment diagnostic sensor 11D. The resistive film 2C and the thin metal film 4C of the third environment diagnostic sensor 11C are electrically connected in series with the resistive film 2D and the thin metal film 4D of the fourth environment diagnostic sensor 11D.

[0051] The material constituting the thin metal film 4D of the fourth environment diagnostic sensor 11D is different from the material constituting the thin metal film 4C of the third environment diagnostic sensor 11C. The material constituting the thin metal film 4C is more easily corroded by the corrosive gas X than the material constituting the thin metal film 4D. The material constituting the thin metal film 4D is more easily corroded by the corrosive gas Y different from the corrosive gas X than the material constituting the thin metal film 4C.

[0052] The initial film thickness TC of the thin metal film 4C of the third environment diagnostic sensor 11C is the same as the initial film thickness TD of the thin metal film 4D of the fourth environment diagnostic sensor 11D. The third environment diagnostic sensor 11C and the fourth environment diagnostic sensor 11D are different from each other only in the constituent material of the thin metal film 4. In the environment diagnostic sensor array 13, the initial resistance value of the thin metal film 4D of the fourth environment diagnostic sensor 11D before exposure to the corrosive gas is set to be smaller than the initial resistance value of the thin metal film 4C of the third environment diagnostic sensor 11C before exposure to the corrosive gas. Furthermore, the amount of change R of the combined resistance value of the third environment diagnostic sensor 11C before and after the thin metal film 4C is broken due to corrosion is C is the change amount R of the composite resistance value of the fourth environment diagnostic sensor 11D before and after the metal thin film 4D is broken due to corrosion. D is set smaller than

[0053] 9 and 10, in the environment diagnostic device 102, the combined resistance value of the environment diagnostic sensor array 12 changes with the progress of corrosion of the metal thin film 4C and the metal thin film 4D. The combined resistance value of the environment diagnostic sensor array 12 changes in two ways depending on the corrosive gas contained in the installation environment of the environment diagnostic device 103.

[0054] 9, in the environment X containing the corrosive gas X, the metal thin film 4C is more susceptible to corrosion by the corrosive gas X than the metal thin film 4D, so that the metal thin film 4C corrodes and breaks before the metal thin film 4D does. When the metal thin film 4C breaks, the combined resistance value of the resistive film 2C and the metal thin film 4C in the third environment diagnostic sensor 11C changes significantly, and the combined resistance value of the environment diagnostic sensor array 13 also changes in the same way. After that, when the metal thin film 4D breaks in the environment X, the combined resistance value of the resistive film 2D and the metal thin film 4D in the fourth environment diagnostic sensor 11D changes significantly, and the combined resistance value of the environment diagnostic sensor array 13 also changes in the same way.

[0055] 10, in environment Y containing corrosive gas Y, the metal thin film 4D is more susceptible to corrosion by the corrosive gas Y than the metal thin film 4C, so the metal thin film 4D corrodes and breaks before the metal thin film 4C does. When the metal thin film 4D breaks, the combined resistance value of the resistive film 2D and the metal thin film 4D in the fourth environment diagnostic sensor 11D changes significantly, and the combined resistance value of the environment diagnostic sensor array 13 also changes in the same way. After that, when the metal thin film 4C breaks in environment X, the combined resistance value of the resistive film 2C and the metal thin film 4C in the third environment diagnostic sensor 11C changes significantly, and the combined resistance value of the environment diagnostic sensor array 13 also changes in the same way.

[0056] The change amount R of the combined resistance value of the third environment diagnostic sensor 11C before and after the metal thin film 4C is broken due to corrosion C is the change amount R of the composite resistance value of the fourth environment diagnostic sensor 11D before and after the metal thin film 4D is broken due to corrosion. D Therefore, according to the environment diagnostic device 103, the change amount R of the combined resistance value of the environment diagnostic sensor array 13 is C By detecting the break in the metal thin film 4C, the change amount R of the combined resistance value of the environmental diagnostic sensor array 13 is detected. D By detecting the above, the disconnection of the thin metal film 4D can be detected. Furthermore, the initial change in the combined resistance value of the environmental diagnostic sensor array 13 is equal to or greater than the above change R C If so, the installation environment is environment X, and the change amount R D If so, it can be detected that the installation environment is environment Y.

[0057] Embodiment 4 11, unless otherwise specified, the environment diagnosis device 104 according to the embodiment 4 has the same configuration and effects as those of the above-mentioned embodiment 2. Therefore, the same components as those of the above-mentioned embodiment 2 are denoted by the same reference numerals, and the description thereof will not be repeated.

[0058] 11, the environment diagnostic device 104 according to the fourth embodiment includes an environment diagnostic sensor array 14. The environment diagnostic sensor array 14 includes a fifth environment diagnostic sensor 11E, a sixth environment diagnostic sensor 11F, a seventh environment diagnostic sensor 11G, and an eighth environment diagnostic sensor 11H. The fifth environment diagnostic sensor 11E, the sixth environment diagnostic sensor 11F, the seventh environment diagnostic sensor 11G, and the eighth environment diagnostic sensor 11H have the same configuration and effects as the environment diagnostic sensor 11 according to the first embodiment.

[0059] As shown in FIG. 11, the fifth environment diagnostic sensor 11E, the sixth environment diagnostic sensor 11F, the seventh environment diagnostic sensor 11G, and the eighth environment diagnostic sensor 11H are electrically connected in series with each other.

[0060] As shown in Fig. 11, the initial film thickness TF of the metal thin film 4F of the sixth environment diagnostic sensor 11F before exposure to the corrosive gas is thicker than the initial film thickness TE of the metal thin film 4E of the fifth environment diagnostic sensor 11E before exposure to the corrosive gas. The material constituting the metal thin film 4F of the sixth environment diagnostic sensor 11F is the same as the material constituting the metal thin film 4E of the fifth environment diagnostic sensor 11E. Only the initial film thickness of the metal thin film is different between the fifth environment diagnostic sensor 11E and the sixth environment diagnostic sensor 11F. The initial resistance value of the metal thin film 4F of the sixth environment diagnostic sensor 11F before exposure to the corrosive gas is smaller than the initial resistance value of the metal thin film 4E of the fifth environment diagnostic sensor 11E before exposure to the corrosive gas.

[0061] The initial film thickness TH of the thin metal film 4H of the eighth environment diagnostic sensor 11H before exposure to the corrosive gas is thicker than the initial film thickness TG of the thin metal film 4G of the seventh environment diagnostic sensor 11G before exposure to the corrosive gas. The material constituting the thin metal film 4H of the eighth environment diagnostic sensor 11H is the same as the material constituting the thin metal film 4G of the seventh environment diagnostic sensor 11G. Only the initial film thickness of the thin metal film is different between the seventh environment diagnostic sensor 11G and the eighth environment diagnostic sensor 11H. The initial resistance value of the thin metal film 4H of the eighth environment diagnostic sensor 11H before exposure to the corrosive gas is smaller than the initial resistance value of the thin metal film 4G of the seventh environment diagnostic sensor 11G before exposure to the corrosive gas.

[0062] The material constituting the thin metal film 4G of the seventh environment diagnostic sensor 11G and the thin metal film 4H of the eighth environment diagnostic sensor 11H is different from the material constituting the thin metal film 4E of the fifth environment diagnostic sensor 11E and the thin metal film 4F of the sixth environment diagnostic sensor 11F. The material constituting the thin metal film 4E and the thin metal film 4F is more easily corroded by the corrosive gas X than, for example, the material constituting the thin metal film 4G and the thin metal film 4H. The material constituting the thin metal film 4G and the thin metal film 4H is more easily corroded by the corrosive gas Y than, for example, the material constituting the thin metal film 4E and the thin metal film 4F.

[0063] The change amount R of the combined resistance value of the fifth environment diagnostic sensor 11E before and after the metal thin film 4E is broken due to corrosion E is the change amount R of the combined resistance value of the sixth environmental diagnostic sensor 11F before and after the metal thin film 4F is broken due to corrosion. F The change amount R of the combined resistance value of the seventh environment diagnostic sensor 11G before and after the metal thin film 4G is broken due to corrosion is set to be smaller than the G is the change amount R of the combined resistance value of the eighth environmental diagnostic sensor 11H before and after the metal thin film 4H is broken due to corrosion. H The change amount R of the combined resistance of the sixth environment diagnostic sensor 11F is set to be smaller than the F is the change in the combined resistance value of the seventh environmental diagnostic sensor 11G, R G is set smaller than

[0064] 12 and 13, in the environment diagnostic device 104, the combined resistance value of the environment diagnostic sensor array 14 changes with the progress of corrosion of the metal thin films 4E, 4F, 4G, and 4H. The combined resistance value of the environment diagnostic sensor array 14 also changes in two ways depending on the corrosive gas contained in the installation environment of the environment diagnostic device 104, similar to the combined resistance value of the environment diagnostic sensor array 13 in the third embodiment.

[0065] 12, in an environment X containing a corrosive gas X, the metal thin films 4E and 4F are more susceptible to corrosion by the corrosive gas X than the metal thin films 4G and 4H, the metal thin film 4E is more susceptible to corrosion by the corrosive gas X than the metal thin film 4F, and the metal thin film 4G is more susceptible to corrosion by the corrosive gas X than the metal thin film 4H. Therefore, breaks due to corrosion occur in the order of the metal thin film 4E, the metal thin film 4F, the metal thin film 4G, and the metal thin film 4H.

[0066] As shown in Figure 13, in environment Y containing corrosive gas Y, metal thin film 4G and metal thin film 4H are more susceptible to corrosion by corrosive gas Y than metal thin film 4E and metal thin film 4F, metal thin film 4G is more susceptible to corrosion by corrosive gas Y than metal thin film 4H, and metal thin film 4E is more susceptible to corrosion by corrosive gas Y than metal thin film 4F, so that breaks due to corrosion occur in the order of metal thin film 4G, metal thin film 4H, metal thin film 4E, and metal thin film 4F.

[0067] As each metal thin film breaks, the combined resistance value of the environmental diagnostic sensor including the broken metal thin film changes, and the combined resistance value of the environmental diagnostic sensor array 14 also changes in the same manner. The amount of change R of the combined resistance value of the fifth environmental diagnostic sensor 11E before and after the metal thin film 4E breaks due to corrosion is E is the change amount R of the combined resistance value of the sixth environmental diagnostic sensor 11F before and after the metal thin film 4F is broken due to corrosion. F The change in the combined resistance value of the seventh environmental diagnostic sensor 11G before and after the metal thin film 4G is broken due to corrosion is R G is the change amount R of the combined resistance value of the eighth environmental diagnostic sensor 11H before and after the metal thin film 4H is broken due to corrosion. H The change amount R of the combined resistance value of the sixth environmental diagnostic sensor 11F is smaller than F is the change in the combined resistance value of the seventh environmental diagnostic sensor 11G, R G Therefore, according to the environment diagnostic device 104, the amount of change in the combined resistance value of the environment diagnostic sensor array 14 is smaller than the amount of change R E ~R HBy detecting which of the thin metal films 4E to 4H is broken, it is possible to detect a break in any of the thin metal films 4E to 4H. E If so, the installation environment is environment X, and the change amount R G If so, it can be detected that the installation environment is environment Y.

[0068] Embodiment 5. 14, unless otherwise specified, the environment diagnosis device 105 according to the embodiment 5 has the same configuration and effects as those of the above-mentioned embodiment 2. Therefore, the same components as those of the above-mentioned embodiment 2 are denoted by the same reference numerals, and the description thereof will not be repeated.

[0069] As shown in FIG. 14, the environment diagnostic device 105 according to the fifth embodiment includes an environment diagnostic sensor array 12, a circuit board 60 as a holding base, and a plurality of fixing members 50. Each of the first environment diagnostic sensor 11A and the second environment diagnostic sensor 11B included in the environment diagnostic sensor array 12 is fixed to the circuit board 60 by the fixing members 50 in an individually detachable manner. The environment diagnostic device 105 differs from the environment diagnostic device 102 in that each of the first environment diagnostic sensor 11A and the second environment diagnostic sensor 11B is fixed to the circuit board 60 by the fixing members 50 in an individually detachable manner, not by the joining members 63 (see FIG. 5). The circuit board 60 has a structure for engaging with the fixing members 50.

[0070] Preferably, the fixing member 50 electrically connects the first environment diagnostic sensor 11A and the second environment diagnostic sensor 11B to the wiring pattern of the circuit board 60, respectively.

[0071] The fixing member 50 has, for example, a first connection portion 51, a second connection portion 52, a third connection portion 53, and a fourth connection portion 54. The first connection portion 51, the second connection portion 52, the third connection portion 53, and the fourth connection portion 54 are connected to each other in the order of description. The first connection portion 51 is connected to each of the metal thin films 4 of the first environmental diagnostic sensor 11A and the second environmental diagnostic sensor 11B. The first connection portion 51 has a lower surface that contacts, for example, the upper surface of the metal thin film 4. The second connection portion 52 is connected to one of a pair of electrodes 1 of each of the first environmental diagnostic sensor 11A and the second environmental diagnostic sensor 11B. The second connection portion 52 has a side surface that contacts, for example, one side surface of the pair of electrodes 1. The third connection portion 53 is connected to the wiring pattern of the circuit board 60. The fourth connection portion 54 is connected to the board 61 of the circuit board 60. The third connection portion 53 and the fourth connection portion 54 are provided so as to be detachably engaged with the circuit board 60.

[0072] The fixing member 50 includes, for example, a screw. The first connection portion 51 may be configured as a head portion of the screw. The second connection portion 52 may be configured as a shaft portion of the screw. The third connection portion 53 and the fourth connection portion 54 may be configured as threaded portions of the screws. In this case, the board 61 and the wiring pattern of the circuit board 60 each have a screw hole that screws into the screw portion.

[0073] The fixing member 50 does not necessarily have to have the fourth connecting portion 54. Only the wiring pattern of the circuit board 60 may be provided with screw holes.

[0074] In the environment diagnostic device 105, since each of the first environment diagnostic sensor 11A and the second environment diagnostic sensor 11B can be attached and detached individually to the circuit board 60, the timing of fixing each of the first environment diagnostic sensor 11A and the second environment diagnostic sensor 11B to the circuit board 60 is not limited at the time of manufacturing the circuit board 60. In other words, each of the first environment diagnostic sensor 11A and the second environment diagnostic sensor 11B can be attached to the circuit board 60 later. Furthermore, each of the first environment diagnostic sensor 11A and the second environment diagnostic sensor 11B can be replaced individually at any timing without replacing the circuit board 60. Therefore, according to the environment diagnostic device 105, after the metal thin film 4A is broken, for example, the first environment diagnostic sensor 11A can be replaced with a new first environment diagnostic sensor 11A, so that the environment diagnosis can be repeated.

[0075] Embodiment 6 16 and 17, unless otherwise specified, the environment diagnosis device 106 according to the embodiment 6 has the same configuration and effects as those of the above-mentioned embodiment 1. Therefore, the same components as those of the above-mentioned embodiment 1 are denoted by the same reference numerals, and the description thereof will not be repeated.

[0076] The environment diagnostic device 106 includes an environment diagnostic sensor 11I. In the environment diagnostic sensor 11I, the metal thin film 4 is disposed on at least one of a pair of side surfaces of the environment diagnostic sensor 11I facing opposite directions in the second direction DR2. The environment diagnostic sensor 11I includes, for example, a plurality of metal thin films 4 disposed on each of the pair of side surfaces of the environment diagnostic sensor 11I. Note that the metal thin film 4 may be disposed on only one of the pair of side surfaces of the environment diagnostic sensor 11I. In the environment diagnostic sensor 11I, the upper surface of the protective film 3 is exposed.

[0077] The metal thin film 4 is disposed at a distance from the resistive film 2 in the second direction DR2. The metal thin film 4 is separated from the resistive film 2 in the second direction DR2 by a protective film 3. The metal thin film 4 has, for example, a first portion 43 (see FIG. 17 ) disposed so as to overlap the resistive film 2 in the second direction DR2, and a pair of second portions 44 disposed so as to overlap each of the pair of electrodes 1 in the second direction DR2. The first portion 43 is continuous with the pair of second portions 44.

[0078] The metal thin film 4 further has, for example, a third portion disposed on a third side or a fourth side surface of the insulating substrate 5 in the second direction DR2. Note that the metal thin film 4 does not necessarily have to have the third portion.

[0079] The environment diagnostic sensor 11I in the sixth embodiment can be included in each of the environment diagnostic sensor arrays 12, 13, and 14 in the second to fifth embodiments.

[0080] Embodiment 7 18, unless otherwise specified, the environment diagnosis device 107 according to the seventh embodiment has the same configuration and effects as those of the first embodiment. Therefore, the same components as those of the first embodiment are denoted by the same reference numerals, and the description thereof will not be repeated.

[0081] The environmental diagnostic device 107 includes an environmental diagnostic sensor 11J. In the environmental diagnostic sensor 11J, a metal thin film 4 is disposed on the lower surface of an insulating substrate 5. The metal thin film 4 electrically connects the other ends of a pair of electrodes 1 disposed on the lower surface of the insulating substrate 5. The metal thin film 4 has a fourth portion 45 disposed so as to overlap the resistive film 2 in a direction perpendicular to the lower surface of the insulating substrate 5, and a pair of second portions 46 disposed so as to overlap each of the pair of electrodes 1 in the perpendicular direction.

[0082] The environment diagnostic sensor 11J in the seventh embodiment can be included in each of the environment diagnostic sensor arrays 12, 13, and 14 in the second to fifth embodiments.

[0083] <Example of setting the metal thin film thickness> In the environmental diagnostic devices 101 to 107 according to the first to seventh embodiments, the film thickness of the metal thin film 4 can be set based on the degree of corrosion progress of the electric device expected under the usage environment or the corrosion defect thickness expected at the time when a predetermined time has elapsed based on the corrosiveness of the usage environment of the electric device, as described above. FIG. 19 is a graph showing the rate of change over time (corrosion rate) of the corrosion defect thickness (amount of corrosion) of the metal thin film changes depending on the environment. As shown in FIG. 19, the corrosion rate of the metal thin film 4 exposed to a corrosive gas changes depending on the installation environment of the environmental diagnostic device. Corrosion levels 1 and 2 in FIG. 19 indicate the degree of the corrosion rate of the metal thin film 4 depending on the installation environment. The environment of corrosion level 2 is more likely to corrode the metal thin film 4 than the environment of corrosion level 1. Environment 1 refers to an environment in which the corrosion rate of the metal thin film 4 is expected to be slower than the corrosion rate at corrosion level 1. Environment 2 refers to an environment in which the corrosion rate of the metal thin film 4 is expected to be slower than the corrosion rate at corrosion level 2. Environment 3 refers to an environment in which the corrosion rate of the thin metal film 4 is expected to be faster than the corrosion rate at corrosion level 2.

[0084] The thickness of the metal thin film 4 may be set based on the amount of corrosion expected when a predetermined time has elapsed. For example, the thickness of the metal thin film 4 may be set to a thickness equivalent to the amount of corrosion expected when a predetermined time has elapsed. For example, when the environment in which the environmental diagnosis device 102 is installed is assumed to be environment 2, the thickness TA of the metal thin film 4A may be set to be equal to the amount of corrosion expected when a predetermined time has elapsed at corrosion level 1. The thickness TB of the metal thin film 4B may be set to be equal to the amount of corrosion expected when a predetermined time has elapsed at corrosion level 2. In this way, if a break in the metal thin film 4A is detected when the above-mentioned predetermined time has elapsed, but a break in the metal thin film 4B is not detected, it can be estimated that the installation environment of the environmental diagnosis device 102 is environment 2.

[0085] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present disclosure is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0086] 1 Electrode, 2 Resistive film, 2, 2A, 2B, 2C, 2D Resistive film, 3 Protective film, 4, 4A, 4B, 4C, 4D, 4E, 4F, 4G, 4H Metal thin film, 5 Insulating substrate, 6 Internal electrode, 7 Intermediate electrode, 8 External electrode, 10 Fixed resistor, 11, 11I, 11J Environmental diagnostic sensor, 11A First environmental diagnostic sensor, 11B Second environmental diagnostic sensor, 11C Third environmental diagnostic sensor, 11D Fourth environmental diagnostic sensor, 11E Fifth environmental diagnostic sensor, 11F Sixth environmental diagnostic sensor, 11G Seventh environmental diagnostic sensor, 11H Eighth environmental diagnostic sensor, 12, 13, 14 Environmental diagnostic sensor array, 20 Power supply, 30 Resistance measuring device, 31 Central portion, 32 Outer edge portion, 40 Analysis device, 41, 43 First portion, 42, 44 Second portion, 50 Fixing member, 51 First connection portion, 52, second connection portion, 53, third connection portion, 54, fourth connection portion, 60, circuit board, 61, board, 62, wiring, 63, joining member, 101, 102, 103, 104, 105, environmental diagnosis device, 301, voltmeter, 302, ammeter.

Claims

1. An environmental diagnostic sensor for diagnosing the degree of corrosion caused by a corrosive gas, comprising: A pair of electrodes; a resistive film connecting the pair of electrodes; a protective film disposed on the resistive film and capable of suppressing corrosion of the resistive film due to the corrosive gas; a thin metal film having a portion disposed on the protective film that is disposed on the resistive film and that is exposed to the corrosive gas during the diagnosis; the metal thin film is corroded by the corrosive gas when exposed to the corrosive gas, The resistive film and the thin metal film are electrically connected in parallel to each other between the pair of electrodes.

2. Further comprising an insulating substrate having a first surface and a second surface opposite to the first surface; each of the pair of electrodes has one end disposed on the first surface of the insulating substrate and the other end disposed on the second surface; the resistive film and the protective film are disposed on the first surface, The environmental diagnostic sensor according to claim 1 , wherein the thin metal film is disposed on the second surface.

3. The environmental diagnostic sensor according to claim 1 , wherein the protective film covers the resistive film.

4. 2. The environment diagnostic sensor according to claim 1, wherein an initial resistance value of the thin metal film before being exposed to the corrosive gas is smaller than a resistance value of the resistive film.

5. The environmental diagnostic sensor according to claim 4 , wherein a resistance value of the thin metal film after exposure to the corrosive gas is greater than the initial resistance value of the thin metal film.

6. The environment diagnostic sensor according to claim 1 , wherein the thin metal film covers the protective film.

7. The environmental diagnostic sensor according to any one of claims 1 to 6, a measuring device for measuring a combined resistance of the resistive film and the thin metal film; and an analyzer that identifies at least one of the type of the corrosive gas and the degree of corrosion of the metal thin film based on the amount of change in the combined resistance.

8. A plurality of environmental diagnostic sensors; Each of the plurality of environmental diagnostic sensors is an environmental diagnostic sensor according to any one of claims 1 to 6, At least one of an initial film thickness of the metal thin film before exposure to the corrosive gas and a material constituting the metal thin film is different from one another among the plurality of environmental diagnostic sensors, The plurality of environmental diagnostic sensors are electrically connected in series with each other in an environmental diagnostic sensor array.

9. a support table for supporting the plurality of environmental diagnostic sensors; The environmental diagnostic sensor array according to claim 8 , further comprising a plurality of fixing members for individually and detachably fixing each of the plurality of environmental diagnostic sensors to the holding base.

10. The environmental diagnostic sensor array according to claim 8 ; a measuring device for measuring a combined resistance of the plurality of environmental diagnostic sensors; and an analyzer that identifies at least one of the type of the corrosive gas and the degree of corrosion of the metal thin film based on the amount of change in the combined resistance.

11. A pair of electrodes; a resistive film connecting the pair of electrodes; a protective film disposed on the resistive film; a metal thin film exposed to a corrosive gas; the resistive film and the thin metal film are electrically connected in parallel to each other between the pair of electrodes, Further comprising an insulating substrate having a first surface and a second surface opposite to the first surface; each of the pair of electrodes has one end disposed on the first surface of the insulating substrate and the other end disposed on the second surface; the resistive film and the protective film are disposed on the first surface, The thin metal film is disposed on the second surface.