Sensor

Abstract

To provide a sensor which can detect water without consuming power.SOLUTION: In a detection target space, a pair of detection electrodes 5, 6 made of metals with different ionization tendencies, and first and second deliquescent materials 11, 12 to be first and second electrolyte solutions by absorbing water are set. The first deliquescent material 11 is arranged to cover one detection electrode 5 to be a positive electrode. The first electrolyte solution includes ions of a precipitable metal on one detection electrode side 5. The second deliquescent material 12 is arranged to cover the other detection electrode 6 to be a negative electrode and the first deliquescent material 11. In at least one of the first and second deliquescent materials, a fluidity suppression material for suppressing fluidity of the electrolyte solutions is mixed.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a sensor, and more particularly to a sensor suitable for detecting moisture that has infiltrated into the internal space of a hermetically sealed package, for example. [Background technology]

[0002] Sensors that detect moisture, such as humidity sensors, include those that place a moisture-sensitive film between two electrodes and detect humidity based on changes in capacitance or impedance between the two electrodes due to humidity (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 6-94663 Summary of the Invention [Problem to be solved by the invention]

[0004] As described above, in a sensor that detects changes in capacitance or impedance between two electrodes, a current must be constantly flowing between the two electrodes, posing the problem of power consumption.

[0005] The present invention has been made in consideration of the above-mentioned problems, and an object of the present invention is to provide a sensor that can detect moisture without consuming power. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention is configured as follows.

[0007] (1) A sensor according to the present invention is a sensor for detecting moisture in a space to be detected, the sensor including: a pair of detection electrodes made of metals having different ionization tendencies; a first deliquescent substance that absorbs moisture to become a first electrolyte solution; and a second deliquescent substance that absorbs moisture to become a second electrolyte solution, the first deliquescent substance being disposed so as to cover one of the pair of detection electrodes that is a positive electrode; the first electrolyte solution containing ions of a metal that can be precipitated on the side of the one detection electrode; the second deliquescent substance being disposed so as to cover the other of the pair of detection electrodes that is a negative electrode and the first deliquescent substance; at least one of the first and second deliquescent substances is mixed with a fluidity suppressing substance that suppresses the fluidity of at least one of the first and second electrolyte solutions; and the sensor detects the intrusion of moisture into the space to be detected based on an electromotive force generated between the pair of detection electrodes.

[0008] According to the sensor of the present invention, when air containing moisture enters the detection target space, the first and second deliquescent substances absorb moisture to become the first and second electrolyte solutions, and the metal of the other detection electrode, which has a greater tendency to ionize, dissolves into the second electrolyte solution to become metal ions and emits electrons, causing the other detection electrode to become a negative electrode. The electrons emitted from the negative electrode flow into one detection electrode, which becomes a positive electrode, generating an electromotive force between the pair of detection electrodes. In other words, when air containing moisture enters the detection target space, a chemical battery is formed and an electromotive force is generated between the pair of detection electrodes, and the intrusion of air containing moisture can be detected based on this electromotive force.

[0009] In this way, with the sensor of the present invention, there is no need to keep a current flowing between the two electrodes, as in conventional sensors that detect changes in capacitance or impedance between the two electrodes, so no power is consumed, thereby achieving so-called energy conservation.

[0010] Furthermore, since a chemical battery having a simple structure is constructed to detect moisture, the structure of the sensor can be simplified and it is easy to reduce the size of the sensor.

[0011] Furthermore, in one of the detection electrodes, which serves as the positive electrode, the electrons that flow in combine with the ions of a metal in the first electrolyte solution that has a low ionization tendency, causing the metal to precipitate, so hydrogen is not generated at the positive electrode, as in a Voltaic cell. This makes it possible to prevent polarization, in which the generated hydrogen covers the positive electrode, inhibiting the subsequent reaction and causing a sudden drop in electromotive force, as in a Voltaic cell.

[0012] In addition, at least one of the first and second deliquescent substances is mixed with a fluidity suppressing substance that suppresses the fluidity of the electrolyte solution, so that the flow of at least one of the first and second electrolyte solutions is suppressed, thereby suppressing the mixing of the first and second electrolyte solutions and reducing the decrease in electromotive force caused by the mixing of the two electrolyte solutions.

[0013] (2) In a preferred embodiment of the present invention, the space to be detected is an internal space of a package hermetically sealed with an inert gas or dry air.

[0014] According to this embodiment, the internal space of a package that is hermetically sealed with an inert gas or dry air is the detection target space. Therefore, for example, the internal space of a package of an electronic device that houses various elements that may deteriorate and have their characteristics deteriorated due to the infiltration of moisture is the detection target space, and the airtight state of the space can be monitored with a simple configuration.

[0015] (3) In another embodiment of the present invention, the second deliquescent material is mixed with a fluidity suppressing material that suppresses the fluidity of the second electrolyte solution.

[0016] According to this embodiment, since the second deliquescent material is mixed with a fluidity suppressing material that suppresses the fluidity of the second electrolyte solution, the second electrolyte solution produced by the second deliquescent material absorbing moisture is suppressed in its flow and is suppressed from mixing with the first electrolyte solution, thereby reducing the decrease in electromotive force caused by the mixing of the two electrolyte solutions.

[0017] (4) In yet another embodiment of the present invention, the flowability suppressing substance includes conductive particles.

[0018] According to this embodiment, the fluid material mixed with the deliquescent material contains conductive particles, so that the electrolyte solution produced by the deliquescent material absorbing moisture contains conductive particles, which can reduce the internal resistance of the chemical battery formed by the infiltration of moisture-containing air, and can increase the current value flowing between the pair of detection electrodes.

[0019] (5) In one embodiment of the present invention, the flow-inhibiting substance includes a thickener.

[0020] According to this embodiment, the fluid material mixed with the deliquescent material contains a thickener. Therefore, for example, when the deliquescent material is first converted into an electrolyte solution, an appropriate amount is applied to a desired position, and then the solution is heated to return to the deliquescent material, the thickener can impart an appropriate viscosity to the electrolyte solution to be applied, making it easy to apply an appropriate amount to a desired position.

[0021] (6) In another embodiment of the present invention, an insulating base is placed inside the space to be detected, the pair of detection electrodes are formed at a distance from one another on an upper surface of the base, and a separator for suppressing mixing of the first electrolyte solution and the second electrolyte solution is protruded from the spaced-apart area on the upper surface of the base.

[0022] According to this embodiment, a separator that suppresses mixing of the first and second electrolyte solutions is protruded between a pair of detection electrodes formed at a distance from one another on the upper surface of the base, so that the decrease in electromotive force caused by mixing of the two electrolyte solutions can be more effectively reduced.

[0023] (7) In still another embodiment of the present invention, the upper surface of the substrate has a recess in which the central portion is recessed downward compared to the peripheral portion, and the separator is protruded into the recess, and the first deliquescent material and the second deliquescent material are arranged.

[0024] According to this embodiment, the first and second deliquescent substances are arranged in a recess recessed downward in the center of the base, separated by a separator, so that the first and second electrolyte solutions produced when the first and second deliquescent substances absorb moisture can be stably held in each recess separated by the separator. Effect of the Invention

[0025] According to the present invention, when air containing moisture infiltrates the space to be detected, a chemical battery is formed and an electromotive force is generated, and the infiltration of air containing moisture into the space to be detected can be detected based on this electromotive force.

[0026] In this way, the sensor of the present invention detects moisture by configuring a chemical battery with a simple configuration, so that no power is consumed, thereby saving energy, and the sensor configuration can be simplified to achieve miniaturization.

[0027] In addition, at one of the detection electrodes, which serves as the positive electrode, the metal ions contained in the first electrolyte solution are precipitated as metal, and hydrogen is not generated at the positive electrode as in a Voltaic cell. This prevents polarization, in which the generated hydrogen covers the positive electrode, inhibiting the subsequent reaction and causing a sudden drop in electromotive force.

[0028] Furthermore, at least one of the first deliquescent substance and the second deliquescent substance is mixed with a fluidity suppressing substance that suppresses the fluidity of the electrolyte solution, so that mixing of the first and second electrolyte solutions generated when the first and second deliquescent substances absorb moisture can be suppressed, thereby reducing the decrease in electromotive force caused by the mixing of the two electrolyte solutions. [Brief description of the drawings]

[0029] [Figure 1] FIG. 1 is a schematic cross-sectional view showing a schematic configuration of a sensor according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic plan view showing a schematic configuration of the sensor main body of FIG. [Diagram 3] FIG. 3 is a schematic cross-sectional view corresponding to FIG. 1, showing a state in which the first and second deliquescent materials have absorbed moisture and are mixed together. [Figure 4] FIG. 4 is a schematic cross-sectional view showing a schematic configuration of a sensor main body according to another embodiment of the present invention. [Diagram 5] FIG. 5 is a schematic cross-sectional view showing a schematic configuration of a sensor main body according to another embodiment of the present invention. [Figure 6] FIG. 6 is a schematic cross-sectional view showing a schematic configuration of a sensor main body according to another embodiment of the present invention. [Figure 7] FIG. 7 is a schematic cross-sectional view showing a schematic configuration of a sensor main body according to another embodiment of the present invention. [Figure 8] FIG. 8 is a schematic plan view showing a schematic configuration of the sensor main body of FIG. [Figure 9] FIG. 9 is a schematic cross-sectional view showing a schematic configuration of a sensor according to one embodiment of the present invention. [Figure 10] FIG. 10 is a schematic plan view showing a schematic configuration of the sensor main body of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0031] [First embodiment] FIG. 1 is a schematic cross-sectional view showing the schematic configuration of a sensor according to one embodiment of the present invention, and FIG. 2 is a schematic plan view showing the schematic configuration of a sensor body 2 of FIG.

[0032] The sensor 1 of this embodiment detects moisture that has infiltrated into a space to be detected, and is equipped with a sensor body 2 that generates an electromotive force in response to the infiltrating moisture, and a judgment unit 3 that judges whether or not moisture has infiltrated based on the electromotive force generated in the sensor body 2.

[0033] The sensor body 2 has a base 4 having a rectangular outer shape when viewed from above. This base 4 has a flat, rectangular bottom wall portion 4a when viewed from above, a peripheral wall portion 4b formed so as to protrude upward from the outer periphery of the bottom wall portion 4a, and a separator 4c having a rectangular cross section formed so as to protrude upward from the center of the bottom wall portion 4a.

[0034] First and second recesses 21, 22 each having a rectangular shape in plan view are defined in the base 4 by the bottom wall 4a, a peripheral wall 4b on the outer periphery of the bottom wall 4a, and a separator 4c in the center of the bottom wall 4a.

[0035] The separator 4c is formed in the center of the long side direction (left and right direction in FIG. 2) of the rectangular bottom wall 4a in plan view along the short side direction (up and down direction in FIG. 2) so as to connect the opposing peripheral wall portions 4b. The first and second recesses 21, 22 are rectangular in plan view and are partitioned symmetrically by the separator 4c.

[0036] A pair of detection electrodes 5, 6 are formed on the inner bottom surfaces of the first and second recesses 21, 22. The detection electrodes 5, 6 extend toward the short sides from the separator 4c in the center at a slight interval. That is, the separator 4c is provided so as to protrude into the region between the pair of detection electrodes 5, 6.

[0037] The pair of detection electrodes 5, 6 extend toward the short sides and further extend to the inner surface and upper surface of the peripheral wall portion 4b connected to each short side. Conductive wires 9, 10 are electrically connected to the upper surface of each peripheral wall portion 4b, which is the extension end of each detection electrode 5, 6, and each detection electrode 5, 6 is electrically connected to the determination unit 3 via each wire 9, 10.

[0038] The detection electrodes 5 and 6 are each made of a metal having a different ionization tendency. For example, it is formed by a vacuum deposition method, a sputtering method, or a plating method.

[0039] Each of the detection electrodes 5 and 6 has a width slightly narrower than the width along the short side direction (the vertical direction in FIG. 2) of the first and second recesses 21 and 22 which are rectangular in plan view.

[0040] The first recess 21 contains a first deliquescent material 11 that absorbs moisture and dissolves in the absorbed moisture to become a first electrolyte solution.

[0041] In the second recess 22, a second deliquescent material 12 that absorbs moisture to become a second electrolyte solution is accommodated in a state mixed with a fluidity suppressing material that suppresses the fluidity of the second electrolyte solution.

[0042] The fluidity suppressing substance suppresses the flow of the second electrolyte solution generated when the second deliquescent substance 12 absorbs moisture when a chemical battery is constructed as described below, thereby suppressing mixing of the second electrolyte solution with the first electrolyte solution and reducing the decrease in electromotive force.

[0043] The fluidity suppressing substance contains a thickener, which will be described later, in order to suppress the fluidity of the second electrolyte solution, and preferably further contains conductive particles such as carbon black, a surfactant, etc., which assist the battery function.

[0044] In this embodiment, India ink is used as the fluidity suppressing substance, and the second deliquescent substance 12 is mixed with the remaining components of the India ink after the water has been evaporated by heating. The remaining components of the India ink are carbon black, glue, etc.

[0045] The glue also acts as a surfactant, but in this embodiment, as described below, the second electrolyte solution mixed with India ink is used as a thickener to increase the viscosity of the electrolyte solution when it is applied to the detection electrode 6, etc.

[0046] In this embodiment, the second deliquescent material 12 is mixed with the remaining components of the ink after the water has been evaporated by pre-mixing the ink with a second electrolyte solution in which the second deliquescent material 12 is dissolved in water, and then heating the mixed solution to evaporate the water.

[0047] In this way, the second deliquescent material 12 is mixed with the remaining components of the ink after the water has evaporated, so when the second deliquescent material 12 absorbs the water, the second electrolyte solution and the ink are produced, and a mixed solution of the second electrolyte solution and the ink is formed.

[0048] The sensor body 2 is installed in a detection target space in which moisture that has infiltrated therein is to be detected. The detection target space is, for example, the internal space of a package that houses various elements that are degraded by moisture that has infiltrated therein and whose characteristics change.

[0049] This package is, for example, a package for various electronic devices such as an optical transceiver, and is a package that is hermetically sealed with an inert gas such as nitrogen gas or dry air.

[0050] The sensor body 2 installed in the package of such an electronic device is small. In this embodiment, the size of the base body 4, which has a rectangular outer shape in a plan view, is, for example, 3 mm×2 mm. The outer size of the sensor body 2 is not particularly limited, and is appropriately selected depending on the size of the detection target space in which the sensor body 2 is installed.

[0051] The substrate 4 is made of an insulating material such as quartz, glass, ceramic, or glass epoxy.

[0052] In this embodiment, the base 4 is made of Z-plate quartz crystal and is roughly rectangular, with the central separator 4c, the peripheral wall portion 4b on the outer periphery, and the first and second recesses 21, 22 defined thereby being integrally formed by etching.

[0053] The quartz crystal is not limited to Z-cut quartz crystal, but may be AT-cut quartz crystal or quartz crystal with other cutting angles.

[0054] The first deliquescent material 11 is accommodated in the first recess 21 of the base 4, which is partitioned by the separator 4c, so as to cover one of the detection electrodes 5, and its upper surface is lower than the height of the separator 4c. This prevents the first electrolyte solution, which is generated when the first deliquescent material 11 absorbs moisture, from moving directly to the other detection electrode 6 across the separator 4c, and prevents the metal ions contained in the first electrolyte solution from directly transferring electrons e from the other detection electrode 6, as described later. - They are trying to prevent people from receiving the message.

[0055] The second deliquescent material 12, which is mixed with the remaining components of the ink after the water has evaporated, is mostly contained in the second recess 22 of the base 4, which is separated by the separator 4c, so as to cover the other detection electrode 6, and a portion of it is arranged to extend beyond the separator 4c and cover the first deliquescent material 11.

[0056] The first deliquescent material 11 absorbs moisture, dissolves in the absorbed moisture, and becomes a first electrolyte solution, which spreads over one of the detection electrodes 5 .

[0057] The second deliquescent material 12 mixed with the remaining components of the ink after the water has evaporated absorbs water and dissolves in the absorbed water to become a second electrolyte solution, and the remaining components dissolve in the water absorbed by the second deliquescent material 12 to become ink. This produces a second electrolyte solution in which the second electrolyte solution and the ink as a fluidity suppressing material are mixed.

[0058] The second electrolyte solution mixed with the ink spreads over the other detection electrode 6, and a part of the second electrolyte solution spreads over the first deliquescent material 11. At this time, the ink is mixed into the second electrolyte solution, and the flow of the second electrolyte solution is suppressed, so that the second electrolyte solution is suppressed from spreading over the first deliquescent material 11. This suppresses mixing of the second electrolyte solution with the first electrolyte solution that is generated when the first deliquescent material absorbs water.

[0059] The first deliquescent substance 11 and the second deliquescent substance 12, which is a mixture of the remaining components of the ink after the water has evaporated, are contained in each of the recesses 21, 22 in the base 4, so that the second electrolyte solution, which is a mixture of the first electrolyte solution and the ink, remains within each of the recesses 21, 22, and the second electrolyte solution, which is a mixture of the first electrolyte solution and the ink, can be prevented from flowing out to the outside of the detection electrodes 5, 6.

[0060] In order to allow the second electrolyte solution, which is a mixture of the first electrolyte solution and the ink, to spread smoothly over the detection electrodes 5 and 6, the surfaces of the detection electrodes 5 and 6 may be cleaned in advance by ashing or UV irradiation to improve wettability before arranging the first deliquescent material 11 and the second deliquescent material 12, which is a mixture of the remaining components of the ink.

[0061] The first and second deliquescent substances in the first and second recesses 21 and 22 absorb moisture to generate a first and second electrolyte solution, respectively. When a chemical battery is constructed, the first and second electrolyte solutions are mixed, and the metal ions of the first electrolyte solution contained in the mixed electrolyte solution are directly converted into electrons e at the other detection electrode 6. - When the voltage Vcc is received, the current stops flowing to the external circuit, ie, the determination unit 3, and the electromotive force decreases.

[0062] In this embodiment, as described above, the second deliquescent material 12 is mixed with the remaining components of the ink after the water has evaporated, so that the mixing of the first electrolyte solution produced by absorbing the water with the second electrolyte solution whose flow is inhibited by the ink is inhibited. This makes it possible to reduce the decrease in electromotive force caused by the mixing of the first electrolyte solution and the second electrolyte solution.

[0063] Furthermore, in this embodiment, a separator 4c is protrudingly provided between the first recess 21 in which the first deliquescent material 11 is accommodated and the second recess 22 in which the second deliquescent material 12 in which the remaining components of the ink from which the water has been evaporated are accommodated, so that mixing of the first electrolyte solution produced by absorbing water and the second deliquescent material 12 in which the ink produced by absorbing water is mixed can be more effectively suppressed.

[0064] Suppressing the mixing of the first and second electrolyte solutions in this manner is necessary in order to reduce a decrease in electromotive force when a chemical battery is constructed.

[0065] However, if the first electrolyte solution and the second electrolyte solution were completely immiscible, the number of cations would increase on the other detection electrode 6 side, which is the negative electrode, and the number of anions would increase on the other detection electrode 5 side, which is the positive electrode, resulting in an imbalance of charges and a corresponding decrease in electromotive force.

[0066] For this reason, in this embodiment, as described above, a portion of the second deliquescent material 12 mixed with the remaining components of the ink after the water has evaporated is arranged so as to extend beyond the separator 4c and cover the first deliquescent material 11, thereby allowing the first and second electrolyte solutions to mix when a chemical battery is constructed, thereby making it possible to adjust the charge balance.

[0067] The basic function of the separator 4c is to suppress mixing of the first and second electrolyte solutions produced when the first and second deliquescent materials 11, 12 absorb moisture. Therefore, when the amount of the first deliquescent material 11 contained in the first and second recesses 21, 22 and the amount of the second deliquescent material 12 mixed with the remaining components of the ink after the moisture has evaporated are small, the height of the separator 4c from the bottom wall 4a may be lower than the height of the peripheral wall 4b from the bottom wall 4a.

[0068] As the first deliquescent material 11 that absorbs moisture to become the first electrolyte solution, for example, copper chloride (CuCl2) is preferable.

[0069] The second deliquescent material 12 that absorbs moisture to become the second electrolyte solution is preferably any one of calcium chloride (CaCl2), sodium hydroxide (NaOH), magnesium chloride (MgCl2), citric acid (C6H8O7), and potassium carbonate (K2O3), which have high deliquescent properties and easily absorb moisture to become an electrolyte solution. The second deliquescent material 12 in this embodiment is calcium chloride, which has very high deliquescent properties and is inexpensive.

[0070] Calcium chloride has a very high deliquescent property and easily becomes an electrolyte solution. Therefore, by covering the first deliquescent material 11 with calcium chloride, which is the second deliquescent material 12, as described above, the entire material can be filled with the second electrolyte solution, which is generated by the second deliquescent material 12 absorbing moisture, before the first deliquescent material 11 absorbs moisture and changes into the first electrolyte solution.

[0071] The first deliquescent material 11 and the second deliquescent material 12 mixed with the remaining components of ink after the water has evaporated can be accommodated in the first and second recesses 21, 22 as follows.

[0072] That is, under an atmosphere of an inert gas such as nitrogen gas or a dry air atmosphere, the first deliquescent material 11 in a solid state is accommodated in the first recess 21 so as to cover one of the detection electrodes 5. Next, the second deliquescent material 12 in a solid state, which is mixed in advance with the remaining components of the ink from which the water has been evaporated, is accommodated in the second recess 22 so as to cover the other detection electrode 6 and to cover a part of the first deliquescent material 11.

[0073] If it is not possible to work in an inert gas atmosphere such as nitrogen gas or in a dry air atmosphere, the connection between each detection electrode 5, 6 and the judgment unit 3 is cut off to inhibit the movement of electrons, and the work is carried out as follows.

[0074] That is, first, in an atmosphere containing moisture, a first electrolyte solution in which a first deliquescent material 11 is dissolved in water is applied onto one of the detection electrodes 5 in the first recess 21, and the sensor body 2 is heated to evaporate the moisture of the first electrolyte solution to form the first deliquescent material 11 in a solid state. Then, a second electrolyte solution in which a second deliquescent material 12 is dissolved in water is mixed with India ink, and the second electrolyte solution mixed with India ink is applied so as to overlap the other detection electrode 6 in the second recess 22 and a part of the first deliquescent material 11. Then, the sensor body 2 is heated to evaporate the moisture, and the second deliquescent material 12 in a solid state mixed with the remaining components of India ink is formed. By this heating, even if a part of the first deliquescent material 11 is the first electrolyte solution when the second electrolyte solution mixed with India ink is applied, the moisture evaporates and the first deliquescent material 11 returns to its original solid state.

[0075] Since the viscosity of the second electrolyte solution mixed with ink is higher than that of the second electrolyte solution alone, the viscosity of the second electrolyte solution can be adjusted by mixing ink. This makes it easier to control the amount and position of the second electrolyte solution mixed with ink when the second electrolyte solution is applied so as to overlap the other detection electrode 6 and part of the first deliquescent material 11 in the second recess 22 compared to the case of the second electrolyte solution alone.

[0076] In this manner, under an atmosphere containing moisture, the first and second deliquescent substances 11, 12 are treated as a first electrolyte solution in solution state and a second electrolyte solution in which ink is mixed, and finally, under an inert gas atmosphere or a dry air atmosphere, the first electrolyte solution and the second electrolyte solution in which ink is mixed are heated to evaporate the moisture, forming the first deliquescent substance 11 in a solid state and the second deliquescent substance 12 in a solid state in which the remaining components of the ink from which the moisture has evaporated are mixed, and each of the detection electrodes 5, 6 is connected to the determination unit 3.

[0077] One of the pair of detection electrodes 5, 6, the detection electrode 5, is made of a precious metal such as gold (Au) or platinum (Pt), and in this embodiment, gold. This one detection electrode 5 may be made of copper (Cu) instead of gold (Au). The other detection electrode 6 is made of a base metal with a high ionization tendency, such as zinc (Zn), iron (Fe), or nickel (Ni), and in this embodiment, zinc.

[0078] In order to improve adhesion between the base 4 made of quartz crystal and the metals constituting each of the detection electrodes 5, 6, it is preferable to form a base metal film such as chromium (Cr) on the base 4, and then form the metals constituting each of the detection electrodes 5, 6 on the base metal film.

[0079] The sensor 1 of this embodiment is incorporated into the internal space of a package of an electronic device, and the wires 9, 10 connected to the detection electrodes 5, 6 are connected to, for example, a determination unit 3 provided in the electronic device, and the sensor 1 is hermetically sealed. Note that the determination unit 3 only needs to be able to determine whether or not an electromotive force is generated between the pair of detection electrodes 5, 6, and may be housed within the package of the electronic device, or may be installed outside the package.

[0080] The sensor 1 is assembled into the internal space of the package of the electronic device in an inert gas atmosphere or a dry air atmosphere.

[0081] When the assembly work is performed in an atmosphere containing moisture, the first deliquescent material 11 and the second deliquescent material 12 mixed with the remaining components of the ink are treated as the first electrolyte solution in a solution state and the second electrolyte solution mixed with the ink, respectively, as described above. Finally, by heating in an inert gas atmosphere or a dry air atmosphere, the first electrolyte solution becomes the deliquescent material 11 in a solid state, and the second electrolyte solution mixed with the ink becomes the second deliquescent material 12 in a solid state mixed with the remaining components of the ink, and each of the detection electrodes 5 and 6 is connected to the determination unit 3.

[0082] In this embodiment, when air containing moisture invades the space to be detected, the sensor body 2 forms a chemical battery as described below. At this time, an electromotive force, for example, an electromotive force of about 1.5 V, is generated between one detection electrode 5, which serves as the positive electrode, and the other detection electrode 6, which serves as the negative electrode. This electromotive force allows the determination unit 3 provided in the electronic device to detect the intrusion of moisture, and it is possible to light up an appropriate notification unit, for example, a light-emitting element (LED), to notify the intrusion of moisture.

[0083] In this embodiment, the metal constituting one of the detection electrodes 5 is a first metal M1, and its ionization tendency is I M1 The metal constituting the other detection electrode 6 is the second metal M2, and its ionization tendency is I M2 The metal contained in the first electrolyte solution and precipitated on one side of the detection electrode 5 is designated as the third metal M3, and its ionization tendency is IM3 and hydrogen ionization tendency is I H Then, the ionization tendency I M1 , I M2 , I M3 , I H The magnitude relationship between these is as follows: Hydrogen ions are contained in the electrolyte solution that is produced when water is absorbed.

[0084] I M2 >I H >I M3 >I M1 As described above, the first metal M1 constituting one detection electrode 5 is gold (Au), the second metal M2 constituting the other detection electrode 6 is zinc (Zn), and the third metal M3 contained in the first electrolyte solution and precipitated on the side of one detection electrode 5 is copper (Cu). Therefore, their ionization tendencies I Au , I Zn , I Cu The magnitude relationship is shown below.

[0085] I Zn >I H >I Cu >I Au In this embodiment, when air containing moisture enters the detection space, the first deliquescent substance 11, copper chloride, and the second deliquescent substance 12, calcium chloride, which is a mixture of the remaining components of ink after the moisture has evaporated, absorb the moisture and dissolve in the absorbed moisture to become a first electrolyte solution and a second electrolyte solution mixed with ink, which spread over each of the detection electrodes 5 and 6.

[0086] Of the pair of detection electrodes 5, 6, the zinc of the other detection electrode 6 having a greater ionization tendency dissolves into the second electrolyte solution mixed with the India ink.

[0087] At this time, zinc Zn is oxidized to zinc ions Zn 2+ and electron e - That is, the other detection electrode 6 emits electrons e - It becomes a negative electrode that releases

[0088] At the negative electrode, the following reaction occurs:

[0089] Zn → Zn 2+ +2e - The electron e generated at the other detection electrode 6 - flows into one of the detection electrodes 5 via the wire 10, the determination unit 3, and the wire 9.

[0090] At this time, electron e - When the liquid passes through the determination unit 3, the intrusion of moisture is detected.

[0091] At one detection electrode 5, the electrons e - The first electrolyte solution contains copper ions, which are cations with a low ionization tendency. 2+ is electron e - The electrons react with the gold and react with the metal, and the metal is reduced to precipitate copper (Cu). - It becomes the positive electrode that receives

[0092] At the positive electrode, the following reaction occurs:

[0093] Cu 2+ +2e - →Cu As described above, in this embodiment, when air containing moisture enters the detection target space, a chemical battery similar to a Daniel cell, as shown in the following battery formula, is formed.

[0094] (-)Zn|CaCl2(aq)|CuCl2(aq)|Au(+) At this time, an electromotive force is generated between one detection electrode 5 which serves as a positive electrode and the other detection electrode 6 which serves as a negative electrode, and this electromotive force causes the determination unit 3 to determine that moisture has infiltrated.

[0095] In this embodiment, the second deliquescent material 12 is mixed with the remaining components of India ink after the water has been evaporated as a fluidity suppressing material that suppresses the fluidity of the second electrolyte solution produced by absorbing water, so that the second electrolyte solution produced by absorbing water is mixed with India ink that suppresses its fluidity.

[0096] This prevents the first electrolyte solution, which is generated by the first deliquescent material 11 absorbing water, from being mixed with the second electrolyte solution, the flow of which is prevented by the ink. Therefore, when the first and second electrolyte solutions are mixed, the copper ions Cu contained in the first electrolyte solution of the mixed electrolyte solution are reduced. 2+ However, electrons e - Therefore, it is possible to prevent the original electromotive force from being not obtained between the pair of detection electrodes 5 and 6 due to the reception of the electric current.

[0097] Furthermore, in this embodiment, the separator 4c separating the first and second recesses 21, 22 of the base 4 can effectively prevent the first deliquescent material 11 in the first and second recesses 21, 22 and the second deliquescent material, which is a mixture of the remaining components of the ink after the water has been evaporated, from mixing with the first electrolyte solution produced by absorbing water, and the second electrolyte solution mixed with the ink, thereby further effectively reducing the decrease in electromotive force.

[0098] The sensor 1 of the present embodiment only needs to detect and report moisture, and does not need to generate power for a long period of time like a general chemical battery, so it can fully function as a sensor.

[0099] As time passes, the other detection electrode 6, which is the negative electrode, becomes positive. 2+ The negative ion Cl increases on the positive detection electrode 5 side. - As a result, the charge balance is lost due to an increase in the charge of the separator 4c. In this embodiment, however, as described above, a portion of the second deliquescent material 12 mixed with the remaining components of the ink after the water has been evaporated is disposed so as to extend beyond the separator 4c and cover the first deliquescent material 11.

[0100] As a result, the first deliquescent material 11 and the second deliquescent material 12, which is a mixture of the remaining components of the ink, gradually mix with the first electrolyte solution produced by absorbing moisture and the second electrolyte solution mixed with the ink, resulting in a mixed electrolyte solution 25 as shown in FIG. 3. By mixing the first electrolyte solution with the second electrolyte solution mixed with the ink, zinc ions Zn 2+ is the chlorine ion Cl from the negative electrode to the positive electrode. - can move in the solution from the positive electrode to the negative electrode, adjusting the balance of electric charges and suppressing a decrease in electromotive force.

[0101] In Fig. 1, the surface of the second deliquescent material 12 obtained by mixing the first deliquescent material 11 in a solid state with the remaining components of the ink after the water has been evaporated is flat, whereas in Fig. 3, the surface of the electrolyte solution 25 obtained by completely mixing the first electrolyte solution with the second electrolyte solution obtained by mixing the ink is rounded and curved. This is an exaggerated example, and depending on the amount of the second deliquescent material 12 obtained by mixing the first deliquescent material 11 with the remaining components of the ink after the water has been evaporated, the surface may be flat, curved, or uneven, regardless of whether it is in a solid state or a solution state.

[0102] The space to be detected is the internal space of a package of an electronic device that is hermetically sealed with an inert gas or dry air. If the sensor 1 of this embodiment detects the intrusion of moisture-containing air into the internal space of the package after a long period of time has passed, it can be determined that the moisture-containing air has infiltrated into the package due to deterioration of the electronic device over time, and that the electronic device has reached the end of its life.

[0103] Furthermore, if the intrusion of moisture-containing air is detected at an early stage, it can be determined that the airtight sealing of the package of the electronic device is incomplete.

[0104] In this manner, the ingress of moisture-laden atmospheric air into the hermetically sealed package of the electronic device can be monitored.

[0105] Conventional humidity sensors detect changes in capacitance or impedance between two electrodes, so a voltage must be constantly applied between the two electrodes, resulting in power consumption.

[0106] In contrast, the sensor 1 of the present embodiment can detect moisture that has infiltrated into the detection target space without consuming power, and does not require a power source.

[0107] In addition, the sensor body 2 has a simple configuration in which a first deliquescent substance 11, which becomes a second electrolyte solution obtained by mixing a first electrolyte solution and India ink, and a second deliquescent substance 12, which is a mixture of the remaining components of India ink after the water has been evaporated, are arranged in the first and second recesses 21 and 22 so as to cover a pair of detection electrodes 5 and 6 on the base 4, and therefore it is easy to make it compact and inexpensive.

[0108] Furthermore, a chemical battery similar to a Daniel cell is configured, and copper is precipitated on one of the detection electrodes 5, which is the positive electrode, and hydrogen H2 is not generated at the positive electrode as in a Volta cell. Therefore, in this embodiment, unlike a Volta cell, hydrogen generated at the positive electrode accumulates around the positive electrode, making it difficult to transfer electrons, and polarization does not occur, in which the electromotive force drops suddenly.

[0109] In addition, the second deliquescent material 12 contains the remaining components of the ink after the water has evaporated, so that the mixing of the second electrolyte solution with the first electrolyte solution is suppressed, and the copper ions Cu 2+ However, electrons e - This can prevent the electromotive force from being lost.

[0110] The India ink mixed into the second electrolyte solution contains carbon black, and therefore the internal resistance when a chemical battery is constructed can be reduced, and the current flowing through the determination unit 3 increases.

[0111] Furthermore, the separator 4c separating the first and second recesses 21 and 22 of the base 4 can prevent the first electrolyte solution generated by absorbing moisture from mixing with the second electrolyte solution mixed with India ink. 2+ However, electrons e - Therefore, it is possible to more effectively prevent the electromotive force from being lost due to the reception of the electric current.

[0112] Furthermore, rather than completely preventing the first electrolyte solution from mixing with the second electrolyte solution mixed with ink, the two electrolyte solutions are allowed to mix gradually, which allows ions to move through the mixing, making it possible to adjust the balance of electric charges and suppress a decrease in electromotive force.

[0113] In the above embodiment, the second deliquescent substance 12 is mixed with the remaining components of the ink from which the water has been evaporated. However, instead of the second deliquescent substance 12, the first deliquescent substance 11 may be mixed with the remaining components of the ink from which the water has been evaporated, or both the first deliquescent substance 11 and the second deliquescent substance 12 may be mixed with the remaining components of the ink from which the water has been evaporated.

[0114] The remaining components of the ink that suppress the flow of the electrolyte solution in this manner may be mixed with at least one of the first deliquescent substance 11 and the second deliquescent substance 12. This suppresses the flow of at least one of the first and second electrolyte solutions that are generated by the first and second deliquescent substance 11 and 12 absorbing moisture, inhibits the mixing of the two electrolyte solutions, and enables the battery function to be maintained for a long period of time.

[0115] Furthermore, the substance that suppresses the fluidity of the electrolyte solution is not limited to ink, and other thickeners or surfactants may also be used.

[0116] [Second embodiment] FIG. 4 is a schematic cross-sectional view showing the schematic configuration of a sensor body 21 according to another embodiment of the present invention, and parts corresponding to those in FIG. 1 are given the same reference numerals.

[0117] In this embodiment, the sensor body 21 has a moisture-permeable lid 13 bonded to the upper surface of the peripheral wall portion 4b of the base 4, for example by an adhesive, so as to cover the first electrolyte solution 11 contained in the first and second recesses 21, 22 of the base 4 and the second deliquescent material 12, which is a mixture of the remaining components of ink after the water has evaporated.

[0118] The lid 13 is preferably made of a moisture-permeable resin, such as a thermoplastic resin. The resin constituting the lid 13 is preferably, for example, polyimide, cellophane, polyethylene, acrylic, or the like, and in this embodiment, the lid 13 is made of polyimide.

[0119] The other configuration is similar to that of the sensor 1 in FIG.

[0120] In this manner, the first deliquescent substance 11 in the first and second recesses 21, 22 of the base 4 and the second deliquescent substance 12, which is a mixture of the remaining components of the ink after the moisture has evaporated, are covered by the moisture-permeable lid 13. Therefore, even if the work of housing the sensor body 21 in the package of an electronic device cannot be performed in an inert gas atmosphere or a dry air atmosphere, moisture in the air will not penetrate through the lid 13 and into the first and second recesses 21, 22 of the base 4 within the relatively short time required for the work, for example, within a few hours.

[0121] On the other hand, in applications such as detecting moisture contained in the air that has entered the package as the package of an electronic device deteriorates over time, it is not necessary to immediately detect and report the intrusion of moisture-containing air into the package, and it is acceptable for there to be a time delay sufficient for the moisture to penetrate the moisture-permeable lid 13.

[0122] Therefore, this is suitable for cases where it is necessary to install the sensor body 21 in the internal space of the package of an electronic device in the air, rather than in an inert gas or dry air atmosphere.

[0123] By selecting the material, thickness, etc. of the lid 13, the time it takes for moisture that has entered the package of the electronic device to permeate the lid 13 can be changed.

[0124] In addition, the lid 13 can physically protect the first deliquescent substance 11 in the first and second recesses 21, 22 and the second deliquescent substance 12 mixed with the remaining components of ink after the water has evaporated, making them easy to handle.

[0125] The lid 13 may be provided with a large number of minute through holes through which air containing moisture can pass, so that intrusion of air containing moisture can be detected quickly.

[0126] Furthermore, a plurality of shallow grooves may be formed on the upper surface of the separator 4c so as to connect the first and second recesses 21, 22 on both sides of the separator 4c. This allows the second electrolyte solution mixed with India ink in the second recess 22 to easily move through the plurality of grooves toward the first recess 21, so that it is not necessary to dispose the second deliquescent material 12 mixed with the remaining components of India ink so as to cover the first deliquescent material 11 beyond the separator 4c, and accordingly the height of the sensor body 21 can be reduced to achieve a low profile.

[0127] [Third embodiment] FIG. 5 is a schematic cross-sectional view showing a schematic configuration of a sensor body 22 according to still another embodiment of the present invention, and parts corresponding to those in FIG. 4 above are given the same reference numerals.

[0128] In each of the above-described embodiments, the pair of detection electrodes 5 and 6 are electrically connected to the determination unit 3 via conductive wires 9 and 10, respectively.

[0129] In this embodiment, the detection electrodes 5, 6 on the upper surface of the base 42 are conductively connected to the external connection terminals 16, 17 on the outer bottom surface of the base 42 by internal conductors 14, 15 that penetrate the bottom wall portion 4a2.

[0130] That is, in this embodiment, the sensor body 22 is electrically connected to a determination unit 3 provided in the electronic device by bonding each of the external connection terminals 16, 17 to a substrate within a package, which is the detection target space of the electronic device, for example.

[0131] The other configuration is similar to that of the embodiment in FIG.

[0132] [Fourth embodiment] FIG. 6 is a schematic cross-sectional view showing the schematic configuration of a sensor body 23 according to still another embodiment of the present invention, and parts corresponding to those in FIG. 4 above are given the same reference numerals.

[0133] The substrate 43 of the sensor body 23 in this embodiment is made of quartz, which is an anisotropic etching material that is easily etched in specific crystal planes, as in the above embodiments, and in this example, an AT-cut quartz plate is used. Figure 6 shows the crystal axes X, Y', and Z' of this AT-cut quartz plate, with the crystal axis X being +X on the front side of the paper and -X on the back side of the paper.

[0134] In this embodiment, by utilizing the etching anisotropy of the quartz plate, the surface of separator 43c facing the other detection electrode 6 forms inclined surface 43c1 that is inclined downward toward the other detection electrode 6 side.

[0135] In this way, the surface of the separator 43c facing the other detection electrode 6 is an inclined surface 43c1 that inclines downward toward the other detection electrode 6, so that cations in the second electrolyte solution generated when the second deliquescent material 12 mixed with the remaining components of the ink absorbs water can easily move along the inclined surface 43c1 toward one detection electrode 5. Metal ions (cations) in the first electrolyte solution generated when the first deliquescent material 11 on one detection electrode 5 absorbs water can hardly move beyond the separator 43c to the other detection electrode 6 on the opposite side because the side facing the one detection electrode 5 among the side surfaces constituting the separator 43c is not an inclined surface.

[0136] This promotes the movement of cations in the second electrolyte solution, which is generated when the second deliquescent material 12 absorbs moisture, to one of the detection electrodes 5, contributing to the generation of a stable electromotive force. In addition, the deposition of metal ions in the first electrolyte solution, which is generated when the first deliquescent material 11 absorbs moisture, at the other detection electrode 6 can be suppressed, thereby suppressing a decrease in the electromotive force.

[0137] The other configuration is similar to that of the embodiment in FIG.

[0138] In another embodiment of the present invention, the surface of the separator facing one of the detection electrodes 5 may be inclined upward toward the one of the detection electrodes 5, that is, the inclined surface may be inclined so as to protrude upward toward the one of the detection electrodes 5.

[0139] According to this configuration, the first electrolyte solution, which is generated when the first deliquescent material 11 covering one detection electrode 5 serving as the positive electrode absorbs moisture, can be prevented from moving over the inclined surface of the separator toward the other detection electrode 6. This makes it possible to prevent metal ions contained in the first electrolyte solution from moving toward the other detection electrode 6 and directly receiving electrons from the other detection electrode 6, thereby reducing the decrease in electromotive force.

[0140] [Fifth embodiment] Fig. 7 is a schematic cross-sectional view showing a schematic configuration of a sensor body 24 according to another embodiment of the present invention, and Fig. 8 is a schematic plan view thereof. Fig. 7 is a cross-sectional view taken along the cutting line AA in Fig. 8. In Fig. 8, the outer shape of the lid body 134 is indicated by a dashed line.

[0141] In the sensor main body 2, 21-23 of each of the above embodiments, the outer shape of the base 4, 42-43 in plan view is rectangular, but in this embodiment, the outer shape of the base 44 in plan view is circular. That is, the base 44 includes a bottom wall portion 44a that is circular in plan view, a peripheral wall portion 44b that is annular in plan view and stands on the outer periphery of the bottom wall portion 44a, and a separator 44c that is approximately annular in plan view inside the peripheral wall portion 44b. The lid body 134 attached to the base 44 is circular in plan view.

[0142] The inner peripheral surface of the separator 44c is circular in plan view and is concentric with the base 44. The outer peripheral surface of the separator 44c is generally circular in plan view, and one side in the circumferential direction (the right side in FIGS. 7 and 8) is pulled outward and connected to the peripheral wall portion 44b via a step portion 44d.

[0143] One of the detection electrodes 54 has a detection electrode portion 54a which is circular in plan view and is partitioned by the inner surface of the separator 44c, and a connection electrode portion 54b which is pulled out from the one circumferential side of the detection electrode portion 54a and connected to the step portion 44d and the upper surface of the peripheral wall portion 44b.

[0144] The other detection electrode 64 includes a detection electrode portion 64a that is C-shaped in a planar view and concentrically formed in an area partitioned by the outer peripheral surface of separator 44c and the inner peripheral surface of peripheral wall portion 44b so as to surround separator 44c, and a connection electrode portion 64b that is extended from this detection electrode portion 64a to the upper surface of peripheral wall portion 44b on the other side (left side in Figures 7 and 8) facing the one side in the circumferential direction.

[0145] The connection electrode portion 54b drawn out from one circumferential side of the detection electrode portion 54a, which is circular in a planar view, and the connection electrode portion 64b drawn out from the other circumferential side of the detection electrode 64, which is C-shaped in a planar view, are electrically connected to a determination portion (not shown) via conductive wires 9 and 10.

[0146] The first deliquescent material 11 is disposed in a circular shape in plan view in a region that is defined by the inner circumferential surface of the separator 44c so as to cover the detection electrode portion 54a of one detection electrode 54.

[0147] The second deliquescent material 12, which is mixed with the remaining components of the ink after the water has evaporated, is arranged in a circular shape in plan view within the area partitioned by the inner surface of the peripheral wall portion 44b so as to cover the first deliquescent material 11, which is circular in plan view in the center, and to cover the detection electrode portion 64a, which is C-shaped in plan view, of the other detection electrode 64.

[0148] According to this embodiment, since the one and the other detection electrode parts 54a, 64a are formed concentrically with each other, the first deliquescent material 11 and the second deliquescent material 12, which is a mixture of the remaining components of the ink after the water has evaporated, absorb the water to generate the first electrolyte solution, which is generated by absorbing the water, and the second electrolyte solution, which is a mixture of the ink, can be made to have a planar shape close to a circle by the surface tension. Therefore, the first electrolyte solution and the second electrolyte solution, which is a mixture of the ink, can be easily spread evenly over the detection electrode parts 54a, 64a, and an electromotive force can be stably generated.

[0149] The other configuration is similar to that of the embodiment in FIG.

[0150] [Sixth embodiment] In each of the above embodiments, a separator is provided between the first deliquescent material 11 and the second deliquescent material 12, which is a mixture of the remaining components of the ink after the water has been evaporated. However, in other embodiments of the present invention, the separator may be omitted.

[0151] FIG. 9 is a schematic cross-sectional view showing the general configuration of a sensor 15 according to another embodiment of the present invention in which the separator is omitted, and FIG. 10 is a schematic plan view showing the general configuration of a sensor body 25 of FIG.

[0152] The sensor body 25 of this embodiment comprises a base 45 having a rectangular outer shape in a planar view and a recess 8, a pair of detection electrodes 55, 65 formed on the upper surface of the base 45, a first deliquescent material 11 arranged on one of the detection electrodes 55, and a second deliquescent material 12 arranged on the other detection electrode 65 and a part of the first deliquescent material 11, the second deliquescent material 12 being a mixture of the remaining components of ink from which the water has been evaporated.

[0153] The base 45 includes a bottom wall portion 45a having a rectangular shape in a plan view, and a peripheral wall portion 45b having a rectangular ring shape in a plan view that is continuous with the outer periphery of the bottom wall portion 45a. The recess 8 is formed by the bottom wall portion 45a and the peripheral wall portion 45b.

[0154] No separator protrudes from the inner bottom surface of the recess 8, which is rectangular in plan view, and the pair of detection electrodes 55, 65, which are rectangular in plan view and extend from the center in the long side direction (left and right direction in Figs. 9 and 10) toward the opposing short sides at a distance from each other, are formed. Each detection electrode 55, 65 extends toward each short side and further extends to the inner surface and upper surface of the peripheral wall portion 45b connected to each short side.

[0155] The first deliquescent material 11 is disposed in the recess 8 of the base 45 so as to cover one of the detection electrodes 55. The first deliquescent material 11 is disposed at a distance from the other detection electrode 65 so as not to come into contact with the other detection electrode 65.

[0156] In this manner, by disposing the first deliquescent material 11 away from the other detection electrode 65, the time required for the first electrolyte solution generated by absorbing moisture to reach the other detection electrode 65 is lengthened. This lengthens the time required for the metal ions contained in the first electrolyte solution to reach the other detection electrode 65, directly receive electrons, and reduce the electromotive force.

[0157] The second deliquescent material 12 mixed with the remaining components of the ink after the water has evaporated is disposed in the recess 8 of the base 45 so as to cover the other detection electrode 65 and also to cover a part of the first deliquescent material 11. The second deliquescent material 12 mixed with the remaining components of the ink is disposed so as to fill the gap between the first deliquescent material 11 and the other detection electrode 65.

[0158] In this embodiment, a separator is not provided, but the second deliquescent material 12 contains the remaining components of the ink after the water has evaporated, so that the second electrolyte solution produced by absorbing the water contains the ink that suppresses the fluidity of the second electrolyte solution. This suppresses the mixing of the second electrolyte solution and the first electrolyte solution, and the copper ions Cu contained in the first electrolyte solution are prevented from being mixed. 2+ However, electrons e - By receiving this, it is possible to suppress the decrease in electromotive force.

[0159] The other configuration is similar to that of the sensor 1 in FIG. [Explanation of symbols]

[0160] 1,15 Sensor 2,21~25 Sensor body 3 Judgment section 4,42~45 base 4c, 43c, 44c Separator 43c1 Slope 5,55 Detection electrode (one side) 6,65 Detection electrode (other side) 11,12 1st and 2nd deliquescent substances 25 Electrolyte solution 21, 22 First and second recesses 9,10 Wire 13,134 lids

Claims

1. A sensor for detecting moisture in a detection target space, A pair of detection electrodes made of metals having different ionization tendencies, a first deliquescent substance that absorbs moisture to become a first electrolyte solution, and a second deliquescent substance that absorbs moisture to become a second electrolyte solution are installed inside the detection target space, the first deliquescent material is disposed so as to cover one of the pair of detection electrodes which is a positive electrode; the first electrolyte solution contains ions of a metal that can be deposited on the one detection electrode side, the second deliquescent material is disposed so as to cover the other of the pair of detection electrodes, which is a negative electrode, and the first deliquescent material; At least one of the first deliquescent substance and the second deliquescent substance is mixed with a fluidity suppressing substance that suppresses the fluidity of at least one of the first electrolyte solution and the second electrolyte solution, detecting intrusion of moisture into the detection target space based on an electromotive force generated between the pair of detection electrodes; A sensor characterized by:

2. The detection target space is an internal space of a package hermetically sealed with an inert gas or dry air. The sensor of claim 1 .

3. The second deliquescent material is mixed with a fluidity suppressing material that suppresses the fluidity of the second electrolyte solution. The sensor of claim 2.

4. The flowability suppressing material includes conductive particles. The sensor of claim 2.

5. The flow-reducing substance includes a thickener. The sensor of claim 2.

6. an insulating substrate is placed inside the detection target space; The pair of detection electrodes are formed on the upper surface of the base at a distance from each other, and a separator for suppressing mixing of the first electrolyte solution and the second electrolyte solution is provided in a protruding manner in the spaced apart region on the upper surface of the base. The sensor of claim 2.

7. the upper surface of the base body has a recess in which a central portion is recessed downward compared to an outer periphery, and the separator is provided in a protruding manner within the recess, and the first deliquescent material and the second deliquescent material are disposed within the recess. The sensor of claim 6.

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