Sensor and method for manufacturing the same

Abstract

To provide a sensor which can detect water content without consuming power.SOLUTION: In the inside of a detection target space, there are set an insulative base body 4, a pair of detection electrodes 5, 6 on an upper surface of the insulative substrate, the detection electrodes being made of metals with different ionization tendencies, and deliquescent materials 11, 12 arranged to cover the pair of detection electrodes 5, 6, the deliquescent materials absorbing water content and becoming an electrolyte solution. A plurality of trench parts 7a is formed in at least a region of the upper surface of the base body 4 where the pair of detection electrodes 5, 6 is arranged, and water content entrance into the detection target space is detected on the basis of electromotive force generated between the pair of detection electrodes 5, 6.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a sensor and a manufacturing method thereof, and more particularly to a sensor suitable for detecting moisture that has infiltrated into the internal space of a hermetically sealed package, for example, and a manufacturing method thereof. [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 view of the above-mentioned problems, and an object of the present invention is to provide a sensor capable of detecting moisture without consuming power, and a manufacturing method thereof. [Means for solving the problem]

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

[0007] (1) The sensor of the present invention is a sensor for detecting moisture in a space to be detected, and includes an insulating base, a pair of detection electrodes made of metals with different ionization tendencies formed on the upper surface of the base, and a deliquescent material arranged to cover the pair of detection electrodes and absorbs moisture to become an electrolyte solution. A plurality of grooves are formed in the area on the upper surface of the base where at least the pair of detection electrodes are arranged, and the sensor detects the intrusion of moisture into the space to be detected based on the 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 deliquescent material covering the pair of detection electrodes made of metals with different ionization tendencies absorbs moisture to become an electrolyte solution, and an electromotive force is generated 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, 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] A plurality of grooves are formed in the region where the pair of detection electrodes are arranged, and the deliquescent material is arranged so as to cover the pair of detection electrodes, so that a plurality of grooves are formed in the region where the deliquescent material is arranged. Therefore, the electrolyte solution generated when the deliquescent material absorbs moisture can be stably held in the plurality of grooves even when the sensor is tilted, for example.

[0012] When the sensor is miniaturized, the region in which the deliquescent material is arranged becomes a minute region. It is not easy to arrange a solid-state deliquescent material in a desired minute region. In this case, it is easier to arrange the deliquescent material in the desired minute region by dissolving the deliquescent material in water to prepare an electrolyte solution than by dissolving the deliquescent material in a solid state.

[0013] According to the sensor of the present invention, since a plurality of grooves are formed in the region where the detection electrode is formed on the upper surface of the substrate, which is the region where the deliquescent material is arranged, even if the region where the deliquescent material is arranged is a small region, when an electrolyte solution in which the deliquescent material is dissolved in water is dropped into the grooves, the electrolyte solution can be smoothly spread along the grooves to the desired small region by utilizing the capillary phenomenon. The electrolyte solution spread in the desired small region in this way can be heated under an inert gas atmosphere or a dry air atmosphere to evaporate the water, thereby turning the deliquescent material into a solid state.

[0014] (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.

[0015] 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.

[0016] (3) In another embodiment of the present invention, the plurality of grooves are linear in plan view and are formed parallel to one another.

[0017] According to this embodiment, the multiple grooves in the region in which the deliquescent material is placed are linear and formed parallel to each other, so that when an electrolyte solution in which the deliquescent material is dissolved in water is dropped into the grooves, the electrolyte solution can be guided by capillary action along the multiple linear grooves to the desired microregion in which the deliquescent material is to be placed.

[0018] (4) In still another embodiment of the present invention, the depth of the groove is greater than the opening width of the groove.

[0019] According to this embodiment, the opening width of the groove is narrowed to effectively utilize the capillary phenomenon, while the groove is deepened to ensure the amount of electrolyte solution that can be filled in the groove, i.e., the amount of deliquescent material in a solid state obtained by evaporating the water content of the electrolyte solution.

[0020] (5) In one embodiment of the present invention, the deliquescent material includes a first deliquescent material that absorbs moisture to become a first electrolyte solution, and a second deliquescent material that absorbs moisture to become a second electrolyte solution, the first deliquescent material is arranged to cover one of the pair of detection electrodes that is a positive electrode, the first electrolyte solution contains ions of a metal that can be precipitated on the side of the one detection electrode, the second deliquescent material is arranged to cover the other of the pair of detection electrodes that is a negative electrode and the first deliquescent material, each of the pair of detection electrodes is formed on one side and the other side of an electrode non-formation region on the upper surface of the base, and the multiple grooves are formed on the one side and the other side of the electrode non-formation region on the upper surface of the base.

[0021] According to this embodiment, 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 higher ionization tendency, 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, and combine with metal ions in the first electrolyte solution, which have a lower ionization tendency, to precipitate metal. That is, 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.

[0022] In addition, 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.

[0023] A pair of detection electrodes covered with the first and second deliquescent materials are formed on one side and the other side of the electrode non-forming region, and a plurality of grooves are formed on the one side and the other side of the electrode non-forming region, so that even if the region in which the first and second deliquescent materials are arranged is a minute region, when the first and second electrolyte solutions in which the first and second deliquescent materials are dissolved in water are dropped into the grooves, the first and second electrolyte solutions can be smoothly spread along the grooves to the desired minute region by utilizing the capillary phenomenon. The first and second electrolyte solutions spread in the desired minute region in this way can be heated in an inert gas atmosphere or a dry air atmosphere to evaporate the water, thereby turning them into the first and second deliquescent materials in a solid state.

[0024] (6) A method for producing a sensor according to the present invention is a method for producing any one of the sensors (1) to (4) above, comprising the steps of: The method includes the steps of filling the plurality of grooves with the deliquescent material in the form of the electrolyte solution, and drying the filled electrolyte solution to obtain the deliquescent material.

[0025] When the sensor is miniaturized, the region in which the deliquescent material is arranged becomes very small, and it is not easy to arrange a solid deliquescent material in a desired very small region.

[0026] According to the method for manufacturing a sensor of the present invention, a plurality of grooves are formed in the region on the upper surface of the substrate where the detection electrode is formed, which is the region in which the deliquescent material is disposed, and these grooves are filled with an electrolyte solution rather than a solid-state deliquescent material. Therefore, during filling, the electrolyte solution can be smoothly distributed along the plurality of grooves to the desired microregion by utilizing the capillary phenomenon.

[0027] The electrolyte solution that has been spread to the desired micro-region can be dried to evaporate the water and turn it into a solid-state deliquescent material, thereby allowing the deliquescent material to be disposed in the desired micro-region.

[0028] Therefore, the method for producing a sensor according to the present invention is suitable for producing a small sensor in which the region where the deliquescent material is arranged is a very small region.

[0029] (7) A method for producing a sensor according to the present invention is a method for producing the sensor according to (5) above, comprising the steps of: The method includes the steps of filling the first deliquescent material, in the form of the first electrolyte solution, into the plurality of grooves formed on one side of the electrode non-forming region; filling the second deliquescent material, in the form of the second electrolyte solution, into the plurality of grooves formed on the other side of the electrode non-forming region; and drying the first electrolyte solution and the second electrolyte solution filled in the plurality of grooves, respectively, to obtain the first deliquescent material and the second deliquescent material.

[0030] According to the method for manufacturing a sensor of the present invention, the multiple grooves formed on one side of the non-electrode region are filled with a first electrolyte solution rather than a first solid deliquescent material, so that the first electrolyte solution can be smoothly distributed along the multiple grooves to the desired microregions by utilizing capillary action during filling. On the other hand, the multiple grooves formed on the other side of the non-electrode region are filled with a second electrolyte solution rather than a second solid deliquescent material, so that the second electrolyte solution can be smoothly distributed along the multiple grooves to the desired microregions by utilizing capillary action during filling.

[0031] The first and second electrolyte solutions that have been spread throughout the desired micro-regions can be dried to evaporate the water and turn them into the first and second deliquescent substances in a solid state, thereby allowing the first and second deliquescent substances to be disposed in the desired micro-regions, respectively.

[0032] Therefore, the method for manufacturing a sensor according to the present invention is suitable for manufacturing a small sensor in which the regions in which the first and second deliquescent materials are arranged are minute regions. Effect of the Invention

[0033] According to the sensor of the present invention, when air containing moisture enters the space to be detected, a chemical battery is formed and an electromotive force is generated, and based on this electromotive force, the intrusion of air containing moisture into the space to be detected can be detected.

[0034] 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.

[0035] According to the method of manufacturing the sensor of the present invention, the multiple grooves in the region on the top surface of the substrate where the detection electrodes are formed are filled with a liquid electrolyte solution rather than a solid-state deliquescent material. During filling, the electrolyte solution can be smoothly distributed along the multiple grooves to the desired microregions by utilizing capillary action, and the electrolyte solution can be dried to evaporate the water, resulting in a solid-state deliquescent material.

[0036] Therefore, the present invention is suitable for manufacturing a small sensor in which the region where the deliquescent material is arranged is a very small region. [Brief description of the drawings]

[0037] [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 shows the base 4 of FIG. 1, where FIG. 3(a) is a schematic plan view, FIG. 3(b) is a cross-sectional view along the cutting line AA, and FIG. 3(c) is a cross-sectional view along the cutting line BB. [Figure 4] FIG. 4 is a schematic cross-sectional view corresponding to FIG. 1, showing a state in which the first and second deliquescent substances have absorbed moisture and are mixed together. [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. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0038] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0039] [First embodiment] FIG. 1 is a schematic cross-sectional view showing a schematic configuration of a sensor according to one embodiment of the present invention, and FIG. 2 is a schematic plan view showing a schematic configuration of a sensor body 2 of FIG.

[0040] 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.

[0041] The sensor main body 2 includes a base 4 having a rectangular outer shape in plan view. The base 4 includes a flat, rectangular bottom wall 4a in plan view, a peripheral wall 4b having a rectangular annular shape in plan view erected from the outer periphery of the bottom wall 4a, and a separator 4c having a rectangular cross section that protrudes upward and extends along the short side (up and down direction in Fig. 2) at the center in the long side direction (left and right direction in Figs. 1 and 2) of the rectangular bottom wall 4a in plan view to connect the opposing peripheral wall portions 4b, 4b.

[0042] In the base 4, first and second recesses 21, 22, each having a rectangular shape in plan view, are defined symmetrically by a bottom wall portion 4a, a peripheral wall portion 4b, and a separator 4c.

[0043] One detection electrode 5 of a pair of detection electrodes 5, 6 is formed on the entire inner bottom surface of the first recess 21, and the other detection electrode 6 of the pair of detection electrodes 5, 6 is formed on the entire inner bottom surface of the second recess 22.

[0044] The detection electrode 5 on the inner bottom surface of the first recess 21 extends to the inner surface and upper surface of one peripheral wall portion 4b extending along the short side direction (the up-down direction in FIG. 2) of the rectangular base 4 in a plan view. Similarly, the detection electrode 6 on the inner bottom surface of the second recess 22 extends to the inner surface and upper surface of the other peripheral wall portion 4b extending along the short side direction of the base 4.

[0045] Conductive wires 9, 10 are electrically connected to the upper surfaces of the opposing peripheral wall portions 4b, 4b, which are the extended ends of each detection electrode 5, 6, and each detection electrode 5, 6 is electrically connected to the judgment unit 3 via each wire 9, 10.

[0046] 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.

[0047] The first and second recesses 21 and 22 respectively accommodate and dispose first and second deliquescent materials 11 and 12 that absorb moisture and dissolve in the absorbed moisture to become first and second electrolyte solutions.

[0048] The first deliquescent material 11 is accommodated in the first recess 21 of the base 4 separated by the separator 4c so as to cover one detection electrode 5 over its entire surface. The second deliquescent material 12 is accommodated in the second recess 22 of the base 4 separated by the separator 4c so as to cover the other detection electrode 6 over its entire surface, and is disposed so that a part of the second deliquescent material 12 extends beyond the separator 4c to cover the first deliquescent material 11.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] As the sensor 1 is miniaturized, the first and second recesses 21 and 22 that accommodate and dispose the first and second deliquescent materials 11 and 12 also become minute. It is not easy to accommodate and dispose the first and second deliquescent materials 11 and 12 in a solid state in such a minute region.

[0053] Therefore, in the manufacturing method of the sensor of this embodiment, instead of filling the first and second recesses 21, 22 with the first and second deliquescent materials 11, 12 in a solid state, the first and second recesses 21, 22 are filled with first and second electrolyte solutions in which the first and second deliquescent materials 11, 12 are dissolved in water, and the filled first and second electrolyte solutions are heated and dried to evaporate the water and turn the first and second deliquescent materials 11, 12 into solid states.

[0054] A plurality of grooves are formed on the inner bottom surfaces of the first and second recesses 21, 22, i.e., on the upper surface of the base 4, so that the first and second electrolyte solutions can spread smoothly and thoroughly within the first and second recesses 21, 22 when they are filled into the first and second recesses 21, 22.

[0055] FIG. 3 shows this base 4, where (a) is a schematic plan view, (b) is a cross-sectional view along the cutting line AA, and (c) is a cross-sectional view along the cutting line BB.

[0056] On the inner bottom surfaces of the first and second recesses 21, 22, a plurality of linear protrusions 4d extending parallel to each other along the long side direction (left-right direction in Figure 3(a)) of the rectangular base 4 in a plan view are formed in parallel to each other with narrow minute intervals spaced apart and aligned along the short side direction (up-down direction in Figure 3(a)) of the base 4.

[0057] Each of the protrusions 4d has a planar shape that is elongated in the long side direction of the base 4, and a cross-sectional shape along the short side direction of the base 4 is rectangular as shown in FIG. 3(b).

[0058] Of the multiple protrusions 4d of the first recess 21, narrow, minute gaps are formed between each of the protrusions 4d1, 4d1 located at both ends of the short side direction of the base 4 (the up-down direction in Figure 3(a)), which is the arrangement direction of the multiple protrusions 4a, and each of the peripheral wall portions 4b, 4b extending along the long side direction of the base 4 (the left-right direction in Figure 3(a)) adjacent to each of the protrusions 4d1, 4d1.

[0059] Similarly, among the multiple protrusions 4d of the second recess 22, narrow, minute gaps are formed between each of the protrusions 4d2, 4d2 located at both ends of the short side direction of the base 4, which is the arrangement direction of the multiple protrusions 4a, and each of the peripheral wall portions 4b, 4b extending along the long side direction of the base 4 in close proximity to each of the protrusions 4d2, 4d2.

[0060] In addition, narrow minute gaps are formed between one end of each of the multiple protrusions 4d of the first recess 21 in the longitudinal direction (left and right direction in Figure 3 (a)) and the peripheral wall portion 4b extending along the short side direction of the base 4 in close proximity thereto, and narrow minute gaps are formed between the other end of each of the protrusions 4d in the longitudinal direction and the separator 4c extending along the short side direction of the base 4 in close proximity thereto.

[0061] Similarly, narrow, minute gaps are formed between each of the longitudinal ends of the multiple protrusions 4d of the second recess 22 and the peripheral wall portions 4b extending along the short side direction of the base 4 adjacent thereto, and narrow, minute gaps are formed between each of the longitudinal ends of the protrusions 4d and the separators 4c extending along the short side direction of the base 4 adjacent thereto.

[0062] In this manner, by arranging and protruding a plurality of elongated protrusions 4d in the first and second recesses 21, 22 of the base 4, a plurality of grooves with narrow opening widths are formed between adjacent protrusions 4d, between the protrusions 4d and the peripheral wall portion 4b, and between the protrusions 4d and the separator 4c.

[0063] Specifically, a plurality of first grooves 7a extending along the long side direction of the base 4 are formed by adjacent protrusions 4d, 4d of the plurality of protrusions 4d.

[0064] Two second grooves 7b extending along the long side direction of the base 4 are formed by the protrusions 4d1, 4d1 located at both ends of the short side direction of the base 4, which is the arrangement direction of the multiple protrusions 4d of the first recess 21, and the peripheral wall portions 4b, 4b extending adjacent to the protrusions 4d1, 4d1 along the long side direction of the base 4. Similarly, two second grooves 7b extending along the long side direction of the base 4 are formed by the protrusions 4d2, 4d2 located at both ends of the short side direction of the base 4 of the second recess 22, and the peripheral wall portions 4b, 4b extending adjacent to the protrusions 4d2, 4d2 along the long side direction of the base 4.

[0065] A third groove portion 7c extending along the short side direction of the base 4 is formed by each of the longitudinal ends of the multiple protrusions 4d of the first recess 21 and the peripheral wall portion 4b extending along the short side direction of the base 4 in close proximity thereto, and a third groove portion 7c extending along the short side direction of the base 4 is formed by each of the longitudinal ends of the multiple protrusions 4d of the second recess 22 and the peripheral wall portion 4b extending along the short side direction of the base 4 in close proximity thereto.

[0066] A fourth groove portion 7d extending along the short side direction of the base 4 is formed by the other longitudinal ends of each of the multiple protrusions 4d of the first recess 21 and the separators 4c extending along the short side direction of the base 4 in close proximity thereto, and a fourth groove portion 7d extending along the short side direction of the base 4 is formed by the other longitudinal ends of each of the multiple protrusions 4d of the second recess 22 and the separators 4c extending along the short side direction of the base 4 in close proximity thereto.

[0067] The first grooves 7a and second grooves 7b extending along the long side direction of the base 4 communicate at both longitudinal ends with third grooves 7c and fourth grooves 7d extending along the short side direction of the base 4. Therefore, the first grooves 7a, the second grooves 7b, the third grooves 7c, and the fourth grooves 7d are all communicated with each other.

[0068] In addition, when the grooves 7a to 7d are not particularly specified, they will be representatively referred to as "groove 7."

[0069] In this embodiment, the first grooves 7a, which are the most numerous and extend along the long side direction of the base 4, have a groove depth H that is greater than the groove width W, which is the opening width, as shown in FIG. 3(b) (H>W).

[0070] The groove width of the second groove 7b extending along the long side direction of the base 4 and the third and fourth grooves 7c, 7d extending along the short side direction of the base 4 are slightly wider than the groove width of the first groove 7a. When the base 4 is made of quartz (described later), if the groove width of the first groove 7a is made too narrow, the depth of the groove will be shallow due to the anisotropy of quartz, but the existence of the second to fourth grooves 7b to 7d, which have a groove width wider than the first groove 7a, allows the second to fourth grooves 7b to 7d to be dug deeper, making it possible to fill a sufficient amount of electrolyte solution.

[0071] The groove width of the groove portion 7 is, for example, 30 μm or more and 50 μm or less, and the groove depth is, for example, 50 μm or more and 200 μm or less. The substrate 4 is made of an insulating material such as quartz, glass, ceramic, or glass epoxy.

[0072] In this embodiment, the base 4 is made of Z-plate quartz crystal and is roughly rectangular in shape, and the central separator 4c, the peripheral wall portion 4b on the outer periphery, the first and second recesses 21, 22 defined thereby, and the multiple protrusions 4d that form the groove portion 7 are integrally formed by etching.

[0073] 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.

[0074] The top surface of the first deliquescent material 11 contained in the first recess 21 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 over the separator 4c, and prevents 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.

[0075] The second deliquescent material 12 accommodated in the second recess 22 is disposed so that a portion of the second deliquescent material 12 extends beyond the separator 4c and covers the first deliquescent material 11, as described above.

[0076] 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. The second deliquescent material 12 absorbs moisture, dissolves in the absorbed moisture, and becomes a second electrolyte solution, which spreads over the other detection electrode 6, and a part of the second deliquescent material 12 spreads over the first deliquescent material 11.

[0077] Since most of the first deliquescent material 11 and the second deliquescent material 12 are contained within the first recess 21 and the second recess 22 of the base 4, when they absorb moisture and become the first electrolyte solution and the second electrolyte solution, the first electrolyte solution remains within the first recess 21 and most of the second electrolyte solution remains within the second recess 22, thereby preventing the first and second electrolyte solutions from flowing out to the outside of the detection electrodes 5 and 6.

[0078] In order to allow the first and second deliquescent substances 11, 12 that have absorbed moisture to spread smoothly over the detection electrodes 5, 6 as the first and second electrolyte solutions, the surfaces of the detection electrodes 5, 6 may be cleaned in advance by ashing or UV irradiation to improve wettability before the first and second deliquescent substances 11, 12 are placed.

[0079] The separator 4c separating the first and second recesses 21, 22 of the substrate 4 basically has the function of preventing the first and second electrolyte solutions produced when the first and second deliquescent substances in each recess 21, 22 absorb moisture from mixing.

[0080] The first and second deliquescent materials in the first and second recesses 21 and 22 absorb moisture to generate first and second electrolyte solutions, respectively. When a chemical battery is constructed as described below, 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. - This is because if the external circuit, the determining unit 3, receives this signal, no current will flow to the determining unit 3, which is an external circuit.

[0081] On the other hand, if the first and second electrolyte solutions were completely immiscible, when a chemical battery is constructed, the number of cations will increase on the other detection electrode 6 side, which will become the negative electrode, as described below, and the number of anions will increase on the other detection electrode 5 side, which will become the positive electrode, resulting in an imbalance of charges and a decrease in electromotive force.

[0082] Therefore, in this embodiment, as described above, a portion of the second deliquescent material 12 is disposed so as to extend beyond the separator 4c and cover the first deliquescent material 11, so that when a chemical battery is constructed, the first and second electrolyte solutions are allowed to mix, thereby making it possible to adjust the charge balance.

[0083] The basic function of the separator 4c is to suppress mixing of the first and second electrolyte solutions generated when the first and second deliquescent materials 11, 12 absorb moisture. Therefore, when the amounts of the first and second deliquescent materials 11, 12 contained in the first and second recesses 21, 22 are small, the height of the separator 4c from the bottom wall portion 4a may be lower than the height of the peripheral wall portion 4b from the bottom wall portion 4a.

[0084] As the first deliquescent material 11 that absorbs moisture to become the first electrolyte solution, for example, copper chloride (CuCl2) is preferable.

[0085] 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.

[0086] 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.

[0087] In the method of manufacturing the sensor of this embodiment, the first and second deliquescent substances 11, 12 are filled into the first and second recesses 21, 22 as follows.

[0088] That is, in a state in which the connection between each of the detection electrodes 5, 6 and the determination unit 3 is cut off to inhibit the movement of electrons, a first electrolyte solution in which the first deliquescent material 11 is dissolved in water is dropped into the first recess 21. A plurality of grooves 7 that communicate with each other as described above are formed in a linear arrangement on the inner bottom surface of the first recess 21. Therefore, the dropped first electrolyte solution spreads by capillary action along the plurality of first and second grooves 7a, 7b that extend along the long side direction of the rectangular base 4 in a plan view, and also spreads along the plurality of third and fourth grooves 7c, 7d that communicate with the grooves 7a, 7b and extend along the short side direction of the base 4. As a result, the first electrolyte solution is filled into the plurality of grooves 7 and spreads smoothly over the entire area of ​​the rectangular first recess 21 in a plan view.

[0089] Next, the sensor body 2 is heated to evaporate the water content of the first electrolyte solution to form the first deliquescent material 11 in a solid state.

[0090] Thereafter, the second electrolyte solution, which is obtained by dissolving the second deliquescent material 12 in water, is dropped into the second recess 22 and onto the separator 4c. The inner bottom surface of the second recess 22 has a plurality of communicating grooves 7 aligned in a straight line as described above. Therefore, the second electrolyte solution dropped into the second recess 22 spreads by capillary action along the first and second grooves 7a and 7b extending along the long side direction of the rectangular base 4 in plan view, and also spreads along the third and fourth grooves 7c and 7d extending along the short side direction of the base 4, communicating with the grooves 7a and 7b. As a result, the second electrolyte solution is filled into the plurality of grooves 7 and spreads smoothly throughout the entire area of ​​the first recess 21, which is rectangular in plan view.

[0091] Furthermore, the second electrolyte solution dropped onto the separator 4c spreads from the second recess 22 onto the separator 4c and the first deliquescent material 11.

[0092] Thereafter, the sensor body 2 is heated and dried in an inert gas atmosphere or a dry air atmosphere, and the water content of the second electrolyte solution is evaporated to form the solid-state second deliquescent material 12. By this heating, even if a part of the first deliquescent material 11 is in the form of the first electrolyte solution when the second electrolyte solution is dropped, the water content evaporates and the material returns to its original solid state.

[0093] In this manner, the sensor body 2 is heated and dried in an inert gas atmosphere or a dry air atmosphere, and the water content of the first and second electrolyte solutions is evaporated to form the deliquescent materials 11 and 12 in a solid state.

[0094] Thereafter, the detection electrodes 5 and 6 are connected to the determination unit 3, thereby obtaining the sensor 1 of FIG.

[0095] 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.

[0096] 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.

[0097] 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.

[0098] The sensor 1 is assembled in an internal space of the package of the electronic device under an inert gas atmosphere or a dry air atmosphere. When the assembly is performed under an atmosphere containing moisture, the first and second deliquescent materials 11 and 12 are treated as the first and second electrolyte solutions in a solution state as described above, and finally, the first and second electrolyte solutions are heated under an inert gas atmosphere or a dry air atmosphere to evaporate the moisture in the solutions to turn them into the deliquescent materials 11 and 12 in a solid state, and the detection electrodes 5 and 6 are connected to the determination unit 3.

[0099] 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.

[0100] 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 M2The 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 I M3 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.

[0101] 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.

[0102] 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, absorb the moisture and dissolve in the absorbed moisture to become first and second electrolyte solutions, which spread over each of the detection electrodes 5 and 6.

[0103] 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.

[0104] 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

[0105] At the negative electrode, the following reaction occurs:

[0106] 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.

[0107] At this time, electron e - When the liquid passes through the determination unit 3, the intrusion of moisture is detected.

[0108] 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

[0109] At the positive electrode, the following reaction occurs:

[0110] 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.

[0111] (-)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.

[0112] When the first and second deliquescent materials 11 and 12 absorb moisture and the first and second electrolyte solutions are mixed to form a mixed electrolyte solution 25 as shown in FIG. 4, or when the first electrolyte solution is generated by the first deliquescent material 11 absorbing moisture and reaches the other detection electrode 6, the mixed electrolyte solution 25 or the copper ions Cu 2+ The other detection electrode 6 directly transmits electrons e - Therefore, the original electromotive force cannot be obtained between the pair of detection electrodes 5 and 6, but since the sensor 1 of this embodiment only needs to detect and notify moisture and does not need to generate power for a long period of time as in a general chemical battery, there is no problem in terms of the sensor's functionality.

[0113] In Fig. 1, the surfaces of the first and second deliquescent materials 11 and 12 in the solid state are flat, while in Fig. 4, the surface of the electrolyte solution 25 in which the first and second electrolyte solutions are completely mixed is rounded and curved. This is an exaggerated example, and depending on the amounts of the first and second deliquescent materials 11 and 12, the surfaces may be flat, curved, or uneven, regardless of whether they are in the solid state or solution state.

[0114] 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.

[0115] 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.

[0116] In this manner, the ingress of moisture-laden air into the hermetically sealed package of the electronic device can be monitored.

[0117] 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.

[0118] 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.

[0119] In addition, the sensor body 2 has a simple configuration in which the first and second deliquescent materials 11 and 12, which become the first and second electrolyte solutions, are placed in the first and second recesses 21 and 22 so as to cover the pair of detection electrodes 5 and 6 on the base 4, so that it is easy to make it compact and inexpensive.

[0120] 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.

[0121] In this embodiment, the first and second deliquescent substances 11 and 12 are filled as first and second electrolyte solutions into the multiple grooves 7 formed on the inner bottom surfaces of the first and second recesses 21 and 22. During filling, the first and second electrolyte solutions can be smoothly distributed into each recess 21 and 22 along the multiple grooves 7 by utilizing capillary action.

[0122] The first and second electrolyte solutions that have spread throughout the recesses 21, 22 can be heated and dried to evaporate the water and turn them into solid-state first and second deliquescent materials 11, 12. This allows the first and second deliquescent materials 11, 12 to be smoothly accommodated and disposed in the first and second recesses 21, 22 even if the first and second recesses 21, 22 become minute regions as the sensor 1 is made smaller.

[0123] In addition, since a plurality of grooves 7 are formed in the area in which the first and second deliquescent materials 11, 12 are accommodated, the first and second electrolyte solutions generated when the first and second deliquescent materials 11, 12 absorb moisture can be stably held within the plurality of grooves 7 even when, for example, the sensor 1 is tilted.

[0124] In this embodiment, the separator 4c separating the first and second recesses 21 and 22 of the base 4 can prevent the first and second electrolyte solutions generated by the first and second deliquescent substances absorbing moisture in the first and second recesses 21 and 22 from mixing. This prevents the copper ions Cu contained in the first electrolyte solution of the mixed electrolyte solution from being mixed. 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.

[0125] 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. - In this embodiment, however, as described above, a part of the second deliquescent material 12 is disposed so as to extend beyond the separator 4c and cover the first deliquescent material 11.

[0126] As a result, the first and second deliquescent materials 11 and 12 gradually mix with each other to produce the first and second electrolyte solutions, which are generated by absorbing moisture. This mixing of the first and second electrolyte solutions causes the zinc ions Zn 2+ is the chlorine ion Cl from the negative electrode to the positive electrode. - can move through the solution from the positive electrode to the negative electrode, adjusting the balance of electric charges and suppressing a decrease in electromotive force.

[0127] The groove width and groove depth of the groove portion 7 may be different between the first and second recesses 21 and 22 in which the detection electrodes 5 and 6 made of different metal materials are formed. For example, when forming one of the pair of detection electrodes by electrolytic plating, by making the groove width and the like different, it is possible to prevent the groove portion 7 from being filled with the metal deposited as the electrode.

[0128] Furthermore, the shape, number, arrangement, etc. of the groove portion 7 are merely examples, and can be appropriately selected depending on, for example, the shape and size of the area in which the detection electrode is formed so that the electrolyte solution spreads smoothly over the detection electrode.

[0129] For example, the outer shape of the base may be circular when viewed in plan, one of a pair of detection electrodes may be formed in a circular shape on the upper surface of the base, and the other detection electrode may be formed in an annular shape surrounding the one detection electrode and arranged concentrically, with grooves formed along the circumferential direction of each of the circular or annular detection electrodes.

[0130] [Second embodiment] FIG. 5 is a schematic cross-sectional view showing a 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.

[0131] 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 and second deliquescent substances 11, 12 contained in the first and second recesses 21, 22 of the base 4.

[0132] 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.

[0133] The other configuration is similar to that of the sensor 1 in FIG.

[0134] In this manner, the first and second deliquescent materials 11, 12 in the first and second recesses 21, 22 of the base 4 are covered by the moisture-permeable lid 13. Therefore, even if the task 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 task, for example, within a few hours.

[0135] 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.

[0136] 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.

[0137] 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.

[0138] Furthermore, the first and second deliquescent materials 11, 12 in the first and second recesses 21, 22 can be physically protected by the lid 13, making them easy to handle.

[0139] 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.

[0140] 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 deliquescent material 12 in the second recess 22 to easily move toward the first recess 21 through the plurality of grooves, so that it is not necessary to dispose the second deliquescent material 12 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.

[0141] [Third embodiment] FIG. 6 is a schematic cross-sectional view showing the schematic configuration of a sensor body 22 according to still another embodiment of the present invention, and parts corresponding to those in FIG. 5 above are given the same reference numerals.

[0142] 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.

[0143] 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 42a.

[0144] 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.

[0145] The other configurations are the same as those of the embodiment in FIG.

[0146] [Fourth embodiment] FIG. 7 is a schematic cross-sectional view showing the general configuration of a sensor body 23 according to still another embodiment of the present invention, and parts corresponding to those in FIG. 5 above are given the same reference numerals.

[0147] 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 7 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.

[0148] 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.

[0149] 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 absorbs moisture 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 moisture are less likely to move across the separator 43c to the other detection electrode 6 on the opposite side because the side surface of the separator 43c facing the one detection electrode 5 is not an inclined surface.

[0150] 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.

[0151] The other configurations are the same as those of the embodiment in FIG.

[0152] 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.

[0153] 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.

[0154] In each of the above embodiments, the separators 4c, 43c that separate the first recess 21 and the second recess 22 are protruding between them. However, in another embodiment of the present invention, the separator may be omitted and a single recess may be provided.

[0155] Even if the separator is omitted, there is a distance between one detection electrode 5 and the other detection electrode 6, so that during the period until the first electrolyte solution produced when the first deliquescent material 11 of one detection electrode 5 absorbs moisture reaches the other detection electrode 6, an electromotive force can be obtained and the intrusion of moisture can be detected.

[0156] In each of the above embodiments, a chemical battery similar to a Daniel cell is constructed using two types of electrolyte solutions, i.e., the first and second electrolyte solutions generated when the first and second deliquescent materials absorb moisture. However, as another embodiment of the present invention, a chemical battery similar to a Volta cell may be constructed using one type of electrolyte solution generated when one type of deliquescent material absorbs moisture.

[0157] In this case, it is preferable to omit the separator, and the groove may be formed so as to be continuous across the region in which the pair of detection electrodes are formed. [Explanation of symbols]

[0158] 1 Sensor 2,21~23 Sensor body 3 Judgment section 4,42~43 base 4c,43c Separator 4d protrusion 43c1 Slope 5 Detection electrode (one side) 6 Detection electrode (other side) 7 Groove 7a 1st groove 7b Second groove 7c 3rd groove 7d 4th groove 11,12 1st and 2nd deliquescent substances 25 Electrolyte solution 21, 22 First and second recesses 9,10 Wire 13 Lid

Claims

1. A sensor for detecting moisture in a detection target space, An insulating base, a pair of detection electrodes made of metals having different ionization tendencies formed on an upper surface of the base, and a deliquescent substance that is arranged to cover the pair of detection electrodes and absorbs moisture to become an electrolyte solution are installed inside the detection target space, a plurality of grooves are formed in an area on the upper surface of the base where at least one pair of detection electrodes is disposed; 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 plurality of grooves are linear in plan view and are formed parallel to each other. The sensor of claim 2.

4. The depth of the groove is greater than the opening width of the groove. The sensor of claim 2.

5. The deliquescent material includes a first deliquescent material that absorbs moisture to become a first electrolyte solution, and a second deliquescent material that absorbs moisture to become a second electrolyte solution, 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; the pair of detection electrodes are formed on one side and the other side of the upper surface of the base, with an electrode non-formation region in between, where no electrodes are formed; the plurality of grooves are formed on the one side and the other side of the electrode-free region of the upper surface of the base, 3. The sensor according to claim 1 or 2.

6. A method for manufacturing a sensor according to any one of claims 1 to 4, comprising the steps of: The method includes filling the plurality of grooves with the deliquescent material in the form of the electrolyte solution, and drying the filled electrolyte solution to obtain the deliquescent material. A method for manufacturing a sensor comprising the steps of:

7. A method for manufacturing the sensor of claim 5, comprising the steps of: The method includes a step of filling the first deliquescent material in a state of the first electrolyte solution into the plurality of grooves formed on one side of the electrode non-forming region, a step of filling the second deliquescent material in a state of the second electrolyte solution into the plurality of grooves formed on the other side of the electrode non-forming region, and a step of drying the first electrolyte solution and the second electrolyte solution filled in the plurality of grooves, respectively, to obtain the first deliquescent material and the second deliquescent material. A method for manufacturing a sensor comprising the steps of:

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