Melting-solidification sensor element and melting-solidification sensor

Abstract

To provide a melting-solidification sensor element with a simple configuration capable of accurately detecting phase changes between solid and liquid states in a target substance having conductivity in the liquid state.SOLUTION: A melting-solidification sensor element 20 for detecting phase changes between solid and liquid states in a target substance having conductivity in the liquid state comprises: a liquid retention unit 25 in which the target substance in the liquid state is impregnated and retained; and a first electrode unit 21 and a second electrode unit 22 disposed via the liquid retention unit 25. The phase change between the solid and liquid states of the target substance retained in the liquid retention unit 25 is detected by the electrical signal generated between the first electrode unit 21 and the second electrode unit 22.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a melting-freezing sensor element and a melting-freezing sensor for detecting a change between solid and liquid states in a target substance that is conductive in a liquid state. [Background technology]

[0002] In snowy mountainous regions, avalanches can occur as temperatures rise, cutting off railroad and road transport. Furthermore, avalanches can destroy infrastructure such as power lines, gas pipes, and water pipes, significantly affecting the living environment.

[0003] One of the causes of avalanches is the formation of aquifers in the snow layer due to snowmelt caused by rising temperatures and rainfall, which reduces the strength of the snowpack. Similarly, when snow falls from the roof of a structure, an aquifer is formed in the snow layer. In addition, as the snow on the surface repeatedly melts and refreezes, the crystals turn into large granular snow, and as new snow piles up on top of that, a weak layer that can become the starting point for an avalanche is created at the interface with the granular snow.

[0004] Early detection of signs of an avalanche or snowfall is effective in detecting snowmelt at any depth, including the surface of the snow layer, and the formation of aquifers within the snow layer. In other words, it is sufficient to detect the change of state of snow (solid) to water (liquid) on the surface and within the snow layer. For example, when managing and transporting products that require temperature control, such as frozen products, it is necessary to perform temperature control so that the frozen products do not melt. Here, temperature control can be performed by detecting the state change from ice (solid) to water (liquid).

[0005] For example, Patent Documents 1 to 3 propose sensors that detect the presence or absence of moisture (rainfall, snowfall) based on a decrease in electrical resistance when moisture exists between a pair of electrodes. Furthermore, Patent Documents 4 and 5 propose a means for visually detecting temperature by solidifying the contained liquid and configuring it so that the color changes when the solidified liquid melts. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 07-020074 [Patent Document 2] Japanese Patent Application Laid-Open No. 2000-284065 [Patent Document 3] Japanese Patent Application Laid-Open No. 2004-028617 [Patent Document 4] Japanese Patent Application Laid-Open No. 2003-232687 [Patent Document 5] Japanese Patent Application Laid-Open No. 2015-165212 Summary of the Invention [Problem to be solved by the invention]

[0007] Recently, attempts have been made to utilize information and communication technology (the Internet) to perform unmanned avalanche and falling snow detection and temperature control. Here, the sensors disclosed in Patent Documents 1 to 3 cannot detect the presence of moisture between the pair of electrodes, and therefore there is a risk that the formation of an aquifer cannot be detected with high accuracy. Furthermore, in Patent Documents 4 and 5, it is necessary to confirm the color change, and it is difficult to detect it remotely.

[0008] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a melting-freezing sensor element and a melting-freezing sensor that have a simple structure and are capable of accurately detecting a change in the state between solid and liquid in a target substance that is conductive in a liquid state. [Means for solving the problem]

[0009] In order to solve the above problems, the thawing / freezing sensor element of aspect 1 of the present invention is a thawing / freezing sensor element that detects a change in the solid / liquid state of a target substance that is conductive in a liquid state, and is characterized by having a liquid holding portion in which the target substance in a liquid state is impregnated and held, and a first electrode portion and a second electrode portion arranged via the liquid holding portion, and detecting a change in the solid / liquid state of the target substance held in the liquid holding portion by an electrical signal generated between the first electrode portion and the second electrode portion.

[0010] According to the melting / solidification sensor element of aspect 1 of the present invention, since it has a liquid holding portion in which the target substance in a liquid state is impregnated and held, the target substance can be reliably disposed between the first electrode portion and the second electrode portion. When the target substance disposed between the first electrode portion and the second electrode portion changes state from solid to liquid (melts) or from liquid to solid (coagulates), an electrical signal is generated between the first electrode portion and the second electrode portion. By detecting this electrical signal, it is possible to accurately and reliably detect the melting and coagulation of the target substance disposed between the first electrode portion and the second electrode portion.

[0011] The fusion / solidification sensor element of aspect 2 of the present invention is the fusion / solidification sensor element of aspect 1, characterized in that the first electrode portion and the second electrode portion are made of the same material. According to the melting / freezing sensor element of aspect 2 of the present invention, since the first electrode portion and the second electrode portion are made of the same material, the difference between the electrical resistance when the target substance is in a solid state and the electrical resistance when the target substance is in a liquid state is detected as an electrical signal, thereby making it possible to accurately and reliably detect the melting and freezing of the target substance. Furthermore, since the device has a liquid holding portion in which the target substance in a liquid state is impregnated and held, the amount of the target substance interposed between the first electrode portion and the second electrode portion is stable, and the above-mentioned change in electrical resistance can be detected with high accuracy.

[0012] A fusion / solidification sensor element of a third aspect of the present invention is the fusion / solidification sensor element of the first aspect, characterized in that the first electrode portion and the second electrode portion are made of different metal materials. According to the melting / freezing sensor element of the third aspect of the present invention, the first electrode portion and the second electrode portion, which are disposed via the target substance that is conductive in a liquid state, are made of different metal materials, and therefore when the target substance becomes liquid, they form a battery, and a current is generated due to a potential difference between the first electrode portion and the second electrode portion. By detecting this potential or current as an electrical signal, it becomes possible to accurately and reliably detect the melting and freezing of the target substance. Since the melting / solidification sensor element is configured as a battery, it can also be used as a power source.

[0013] The fusion-freezing sensor element of aspect 4 of the present invention is the fusion-freezing sensor element of any one of aspects 1 to 3, characterized in that the liquid holding portion is made of one or more of paper, thread, nonwoven fabric, cloth, and water-absorbing polymer. According to the melting / freezing sensor element of the fourth aspect of the present invention, the liquid holding portion is made of one or more of paper, thread, nonwoven fabric, cloth, and water-absorbent polymer, so that the target substance in a liquid state can be reliably impregnated and held, and a predetermined amount of the target substance can be reliably disposed between the first electrode portion and the second electrode portion. Therefore, it is possible to accurately and reliably detect the melting and freezing of the target substance.

[0014] The fusion / solidification sensor element of aspect 5 of the present invention is characterized in that, in the fusion / solidification sensor element of any one of aspects 1 to 3, the liquid holding portion protrudes outward from between the first electrode portion and the second electrode portion. According to the melting / freezing sensor element of aspect 5 of the present invention, the liquid holding portion protrudes outward from between the first electrode portion and the second electrode portion, so that the target substance can be reliably impregnated into the liquid holding portion, and the melting and freezing of the target substance can be detected accurately and reliably. In addition, "protruding outward from between the first electrode portion and the second electrode portion" means that the liquid holding portion is present and exposed outside of the space between the first electrode portion and the second electrode portion.

[0015] The thawing / solidification sensor of aspect 6 of the present invention is characterized by comprising a sensor unit in which a thawing / solidification sensor element of any one of aspects 1 to 5 of the present invention is arranged, a support member that supports the sensor unit, and a determination unit that determines a change in the solid and liquid state of the target substance held in the liquid holding unit from an electrical signal generated between the first electrode unit and the second electrode unit.

[0016] According to the thawing / solidification sensor of the sixth aspect of the present invention, a sensor unit in which the thawing / solidification sensor element of any one of the first to fourth aspects of the present invention is disposed, and a support member for supporting the sensor unit are provided. Therefore, the thawing / solidification sensor element can be disposed at any position, and it becomes possible to detect the thawing and solidification of the target substance at a predetermined position. In addition, the device is equipped with a judgment unit that judges the change in the solid / liquid state of the target substance held in the liquid holding unit from the electrical signal generated between the first electrode unit and the second electrode unit, making it possible to reliably detect the melting and solidification of the target substance.

[0017] The thawing / solidification sensor of aspect 7 of the present invention is a thawing / solidification sensor that detects a change in the solid / liquid state of a target substance that is conductive in a liquid state, and is characterized by comprising: a sensor unit in which a plurality of thawing / solidification sensor elements according to aspect 3 of the present invention are arranged; a support member that supports the sensor unit; and a determination unit that determines a change in the solid / liquid state of the target substance held in the liquid holding unit from an electrical signal generated between the first electrode unit and the second electrode unit.

[0018] According to the thawing / solidification sensor of aspect 7 of the present invention, a sensor unit is provided in which a plurality of thawing / solidification sensor elements according to aspect 3 of the present invention are arranged, and a support member is provided to support the sensor unit. Therefore, the thawing / solidification sensor elements can be arranged at any position, and it becomes possible to detect the thawing and solidification of the target substance at a predetermined position. In addition, since it is equipped with a judgment unit that judges the change in the solid / liquid state of the target substance held in the liquid holding unit from the electrical signal generated between the first electrode unit and the second electrode unit, it is possible to reliably detect the melting and solidification of the target substance. The sensor unit is provided with a plurality of melting-freezing sensor elements according to the third aspect of the present invention, which constitute a battery when the target substance is in a liquid state, and therefore the sensor unit (melting-freezing sensor elements) can be used as a power source.

[0019] A thawing / solidification sensor according to an eighth aspect of the present invention is the thawing / solidification sensor according to the sixth or seventh aspect, characterized in that the determination unit and the sensor unit are disposed on the same substrate. According to the thawing / solidification sensor of aspect 8 of the present invention, the determination unit and the sensor unit are arranged on the same substrate, so that the thawing / solidification sensor can be made smaller and can be installed in various locations relatively easily.

[0020] The thawing / solidification sensor of aspect 9 of the present invention is the thawing / solidification sensor of any one of aspects 6 to 8, characterized in that the determination unit determines a change in the coexistence state of the solid and liquid of the target substance from a change in the electrical signal generated between the first electrode unit and the second electrode unit. According to the melting / freezing sensor of aspect 9 of the present invention, the change in the coexistence state of the solid and liquid of the target substance is determined from the change in the electrical signal generated between the first electrode portion and the second electrode portion, so that it is possible to accurately detect the sherbet state in which a solid and a liquid coexist.

[0021] The thawing / solidification sensor of aspect 10 of the present invention is the thawing / solidification sensor of any one of aspects 6 to 9, wherein the determination unit transmits an alarm signal in accordance with the determination result of the change in the state of the target substance between solid and liquid. According to the melting / solidification sensor of aspect 10 of the present invention, the determination unit is configured to emit an alarm signal in accordance with the determination result of the change in the state of the target substance between solid and liquid, so that the change in the state of the target substance between solid and liquid can be made known by the alarm signal. [Effects of the Invention]

[0022] According to the present invention, it is possible to provide a melting-freezing sensor element and a melting-freezing sensor that have a simple structure and are capable of accurately detecting a change in the state between solid and liquid in a target substance that is conductive in a liquid state. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a schematic explanatory diagram of a melting-freezing sensor element according to a first embodiment of the present invention; [Figure 2] 1 is a schematic explanatory diagram of a melting-freezing sensor according to an embodiment of the present invention; [Figure 3] FIG. 10 is a schematic explanatory diagram of a melting-freezing sensor element according to a second embodiment of the present invention. [Figure 4]FIG. 10 is a schematic explanatory diagram of a melting-freezing sensor according to another embodiment of the present invention. [Figure 5] FIG. 10 is a schematic explanatory diagram of a melting-freezing sensor element according to another embodiment of the present invention. [Figure 6] FIG. 10 is a schematic explanatory diagram of a melting-freezing sensor element according to another embodiment of the present invention. [Figure 7] FIG. 10 is a schematic explanatory diagram of a melting-freezing sensor according to another embodiment of the present invention. [Figure 8] 1 is a graph showing the relationship between the state of water and electrical resistance in an example. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Note that the following embodiments are specifically described to provide a better understanding of the gist of the invention, and do not limit the present invention unless otherwise specified. Furthermore, the drawings used in the following description may show essential parts enlarged for convenience in order to make the features of the present invention easier to understand, and the dimensional proportions of each component may not necessarily be the same as those in reality.

[0025] The fusion / freezing sensor element 20 and the fusion / freezing sensor 10 of this embodiment detect a change between solid and liquid states in a target substance that is conductive in a liquid state. In this embodiment, the target substance that is conductive in a liquid state is water that exists in nature, and the melting-freezing sensor element 20 and melting-freezing sensor 10 of this embodiment are designed to detect the occurrence of an aquifer due to melting of snow in a snow layer.

[0026] (First embodiment) A melting / freezing sensor element 20 according to a first embodiment of the present invention will be described with reference to FIG. As shown in FIG. 1, the melting / freezing sensor element 20 of this embodiment has a liquid holding portion 25 that is impregnated with and holds a target substance in a liquid state (water in this embodiment), and a first electrode portion 21 and a second electrode portion 22 arranged via the liquid holding portion 25. The first electrode portion 21 and the second electrode portion 22 may be arranged by connecting the first electrode portion 21 and the second electrode portion 22 to the liquid holding portion 25 using a conductive adhesive, or by forming the first electrode portion 21 and the second electrode portion 22 by plating or vapor deposition.

[0027] In the melting / freezing sensor element 20 of this embodiment, an electrical signal generated between the first electrode portion 21 and the second electrode portion 22 is detected depending on the difference between the conductivity (or electrical resistance) when the target substance held in the liquid holding portion 25 is in a solid state (snow or ice) and the conductivity (or electrical resistance) when it is in a liquid state (water). Here, in the case of water that exists in nature, the conductivity in the solid state (snow or ice) is 10 -3 In its liquid state (water), its conductivity is about 10 to 100 μS / cm. In addition, in a sherbet state where the target substance's solid (snow or ice) and liquid (water) coexist, the conductivity changes depending on the ratio of solid (snow or ice) to liquid (water).

[0028] Liquid holder 25 is impregnated with and holds a target substance (water) in a liquid state, and can hold the target substance in a constant shape whether in a solid state or a liquid state. This liquid holding portion 25 may be any insulating material that can be impregnated with the target substance (water) in a liquid state, and is preferably made of, for example, paper, thread, nonwoven fabric, cloth, water-absorbing polymer, etc. In this embodiment, since the target substance is water, it is preferable to perform a hydrophilic treatment on the liquid holding portion 25 to promote the impregnation of water.

[0029] Furthermore, the thickness of liquid holding portion 25 is preferably 0.001 mm or more and 1 mm or less. If the thickness of liquid holding portion 25 is 0.001 mm or more, short-circuiting between first electrode portion 21 and second electrode portion 22 can be suppressed, ensuring stable use. On the other hand, if the thickness of liquid holding portion 25 is 1 mm or less, electrical signals from first electrode portion 21 and second electrode portion 22 can be obtained stably.

[0030] Here, the first electrode portion 21 and the second electrode portion 22 may be made of any conductive material, and examples of such materials that can be used include metal materials such as copper, nickel, gold, silver, platinum, and aluminum, carbon-based materials, inorganic semiconductor materials, and organic semiconductor materials. In this embodiment, the first electrode portion 21 and the second electrode portion 22 are made of the same metal material (copper). In the melting / freezing sensor element 20 of this embodiment, the liquid holding portion 25 is made of nonwoven fabric, and copper plates are bonded to both sides of the nonwoven fabric using a conductive adhesive to form the first electrode portion 21 and the second electrode portion 22.

[0031] Furthermore, the thickness of the first electrode portion 21 and the second electrode portion 22 is preferably 0.001 mm or more and 10 mm or less. If the thickness of the first electrode portion 21 and the second electrode portion 22 is 0.001 mm or more, disconnection due to oxidation or stress can be suppressed, and stable use can be ensured. On the other hand, if the thickness of the first electrode portion 21 and the second electrode portion 22 is 10 mm or less, breakage due to their own weight and increases in costs can be suppressed.

[0032] It is sufficient that the liquid holding portion 25 is arranged between the first electrode portion 21 and the second electrode portion 22, and as shown in Figure 1(a), the first electrode portion 21 may be arranged on one surface in the thickness direction of the sheet-like liquid holding portion 25, and the second electrode portion 22 may be arranged on the other surface in the thickness direction of the liquid holding portion 25. Furthermore, as shown in FIG. 1(b), the first electrode portion 21 and the second electrode portion 22 may be disposed apart from each other on the same surface of the sheet-like liquid holding portion 25.

[0033] As shown in FIG. 2, the melting-freezing sensor 10 of this embodiment includes a sensor section 11 in which the melting-freezing sensor element 20 of this embodiment is arranged, a support member 12 that supports the sensor section 11, and a determination section 16 that determines a change in the state of the target substance held in the liquid holding section 25 between solid (snow or ice) and liquid (water) from an electrical signal generated between the first electrode section 21 and the second electrode section 22.

[0034] In this embodiment, the purpose is to detect snowmelt at any depth, including the surface of the snow layer, and the generation of an aquifer due to snowmelt.Therefore, the support member 12 is plate-shaped, rod-shaped, or cylindrical in shape so that it can be installed in the snow layer, and sensor units 11 are arranged at multiple locations along the length of the support member 12. It can be inserted into the snow layer at any depth, or placed at any height above the ground so that it can be placed in the snow as it accumulates.

[0035] When the support member 12 is cylindrical, wiring for transmitting an electrical signal from the sensor unit 11 to the determination unit 16 may be disposed inside the support member 12 . In addition, by arranging a communication device to an external server or the like in the judgment unit 16, the change in the state of the target substance held in the liquid holding unit 25 between solid (snow or ice) and liquid (water) may be judged by the external server or the like.

[0036] A method for detecting the occurrence of an aquifer in a snow layer using the melting-freezing sensor element 20 and the melting-freezing sensor 10 of this embodiment will be described below. First, the melting / solidification sensor element 20 is prepared in a state where the liquid holding portion 25 is not impregnated with the target substance. Next, the target substance (water) in a liquid state is impregnated into the liquid holding portion 25, and the target substance is solidified into a solid state (ice). The melting / freezing sensor element 20 in this state is disposed in the sensor portion 11. Then, the melting / freezing sensor 10 of this embodiment is disposed so that the sensor unit 11 is located at a predetermined position in the snow layer.

[0037] When an aquifer is formed in the snow layer due to temperature rise or rainfall, the target substance in a solid state (ice) held in the liquid holding portion 25 of the melting / freezing sensor element 20 melts and turns into a liquid state (water). Here, the judgment unit 16 detects the electrical signal generated between the first electrode unit 21 and the second electrode unit 22 depending on the difference in conductivity (or electrical resistance) between the solid state (snow or ice) and the liquid state (water), and detects that the target substance in the solid state (snow or ice) has melted and become a liquid state (water). It is also possible to detect the sherbet state (ratio of solid (snow or ice) to liquid (water)) in which the target substance's solid (snow or ice) and liquid (water) coexist.

[0038] This allows the detection of melting snow in the snow layer and the formation of aquifers associated with snowmelt, and the risk of avalanches and falling snow to be determined.In addition, because it is possible to detect snow melting and refreezing, it is possible to predict the occurrence of granular snow, which occurs when crystals grow larger due to repeated melting and refreezing, and when new snow accumulates on top of granular snow, it is possible to predict the occurrence of a weak layer at the interface that can cause avalanches.

[0039] According to the melting / freezing sensor element 20 of the first embodiment configured as described above, since it has a liquid holding portion 25 in which the target substance (water) in a liquid state is impregnated and held, it is possible to reliably arrange the target substance in a liquid state between the first electrode portion 21 and the second electrode portion 22. By detecting the electrical signal generated between the first electrode portion 21 and the second electrode portion 22, when the target substance disposed between the first electrode portion 21 and the second electrode portion 22 changes state (melts) from a solid (snow or ice) to a liquid (water) or changes state (freezes) from a liquid (water) to a solid (snow or ice), an electrical signal is generated between the first electrode portion 21 and the second electrode portion 22, and by detecting this electrical signal, it is possible to accurately and reliably detect the melting and freezing of the target substance, and the sherbet state in which a solid (snow or ice) and a liquid (water) coexist.

[0040] In the melting / freezing sensor element 20 of this embodiment, the first electrode portion 21 and the second electrode portion 22 are made of the same material, so by detecting the difference in electrical resistance when the target substance held in the liquid holding portion 25 is in a solid state (snow or ice) and when the target substance is in a liquid state (water) as an electrical signal, it is possible to accurately and reliably detect the melting and freezing of the target substance. In addition, since it has a liquid holding portion 25 that is impregnated with and holds the target substance (water) in a liquid state, the amount of target substance present between the first electrode portion 21 and the second electrode portion 22 is stable, and changes in the electrical resistance between the first electrode portion 21 and the second electrode portion 22 can be detected with high accuracy.

[0041] In the melting / freezing sensor element 20 of this embodiment, when the liquid holding portion 25 is made of one or more of paper, thread, nonwoven fabric, cloth, and water-absorbing polymer, it can reliably impregnate and hold the target substance (water) in a liquid state, and a predetermined amount of the target substance can be reliably disposed between the first electrode portion 21 and the second electrode portion 22. Therefore, it becomes possible to accurately and reliably detect the melting and freezing of the target substance.

[0042] The melting / freezing sensor 10 of this embodiment is equipped with a sensor unit 11 in which the melting / freezing sensor element 20 of this embodiment is arranged, and a support member 12 that supports this sensor unit 11, so that the melting / freezing sensor element 20 can be arranged at any position, and it becomes possible to detect the melting and freezing of the target substance at a predetermined position. In addition, it is equipped with a judgment unit 16 that judges the change in state between solid (snow or ice) and liquid (water) of the target substance held in the liquid holding unit 25 from the electrical signal generated between the first electrode unit 21 and the second electrode unit 22, making it possible to reliably detect the melting and solidification of the target substance. Therefore, for example, by placing this melting / freezing sensor 10 in a snow layer, it is possible to detect the formation of an aquifer in the snow layer, and to determine the risk of an avalanche or falling snow.

[0043] (Second embodiment) A melting / solidification sensor element 120 according to a second embodiment of the present invention will be described with reference to Fig. 2. Note that the same components as those in the first embodiment will be given the same reference numerals and detailed description thereof will be omitted. As shown in FIG. 3, the melting / freezing sensor element 120 of this embodiment has a liquid holding portion 25 in which a target substance (water) in a liquid state is impregnated and held, and a first electrode portion 121 and a second electrode portion 122 arranged via the liquid holding portion 25.

[0044] In the melting / solidification sensor element 120 of this embodiment, the first electrode portion 121 and the second electrode portion 122 are made of different metal materials. Since the first electrode portion 121 and the second electrode portion 122 are made of different metal materials (i.e., metal materials with different ionization tendencies), when the liquid holding portion 25 becomes conductive, the melting / solidification sensor element 120 forms a battery.

[0045] Then, a current is generated due to the potential difference between the first electrode portion 121 and the second electrode portion 122, and by detecting this potential or current as an electrical signal, it is possible to detect that the target substance held in the liquid holding portion 25 has melted from a solid state (snow or ice) to a liquid state (water).

[0046] In this embodiment, it is preferable that a plurality of fusion / solidification sensor elements 120 are disposed in one sensor section 11 of the fusion / solidification sensor 10 shown in FIG. As described above, the fusion / solidification sensor element 120 constitutes a battery, so by arranging multiple fusion / solidification sensor elements 120 in series, the potential difference becomes larger, making it easier to use the fusion / solidification sensor element 120 as a power source.

[0047] According to the melting / solidification sensor element 120 of the second embodiment configured as described above, it is possible to obtain the same effects as those of the first embodiment. Furthermore, according to the second embodiment of the thawing / freezing sensor element 120, the first electrode portion 121 and the second electrode portion 122 disposed via the liquid holding portion 25 are made of different metal materials, so that when the liquid holding portion 25 becomes conductive, the thawing / freezing sensor element 120 forms a battery, and a current is generated due to the potential difference between the first electrode portion 121 and the second electrode portion 122. By detecting this potential or current as an electrical signal, it becomes possible to accurately and reliably detect the thawing and freezing of the target substance (water). Furthermore, since the melting / solidification sensor element 120 is configured as a battery, it can also be used as a power source.

[0048] Furthermore, in this embodiment, since a plurality of thawing / solidification sensor elements 120 are arranged in the sensor section 11, it becomes possible to use a plurality of thawing / solidification sensor elements 120 as a power source. Therefore, when the target substance held in the liquid holding portion 25 melts from a solid state (snow or ice) to a liquid state (water) and the melting-freezing sensor element 120 acts as a battery, communication is performed using the power generated by this melting-freezing sensor element 120, making it possible to detect the formation of an aquifer in the snow layer remotely, even without the need for another power supply device.

[0049] Although one embodiment of the present invention has been described above, the present invention is not limited to this and can be modified as appropriate within the scope of the technical idea of ​​the invention.

[0050] For example, in this embodiment, the sensor is described as a melting / freezing sensor that detects the formation of an aquifer in a snow layer, but the sensor is not limited to this and can be applied to any purpose as long as it detects a change from a solid to a liquid state (melting) in a target substance that is conductive in a liquid state, or a change from a liquid to a solid state (freezing) in a target substance that is conductive in a liquid state. For example, the sensor can be used as a sensor to ensure a frozen state, or conversely, as a sensor to warn of freezing of an object that should not be frozen.

[0051] Furthermore, in this embodiment, a description has been given of a configuration in which a plurality of sensor units are arranged, but this is not limited thereto, and as shown in FIG. 4, a configuration in which only one sensor unit is arranged may also be used. Furthermore, in this embodiment, the target substance has been described by taking water as an example, but the target substance is not limited to this and may be any substance that is conductive in a liquid state.

[0052] 5, the first electrode section 21 and the second electrode section 22 may be stacked via a liquid holding section 25. In this case, as shown in FIG. 5, it is preferable that the area of ​​the liquid holding section 25 is larger than the areas of the first electrode section 21 and the second electrode section 22 when viewed in the stacking direction, and that a portion of the liquid holding section 25 protrudes outside between the first electrode section 21 and the second electrode section 22. With this configuration, it is possible to reliably impregnate the liquid holding portion 25 with the target substance (water).

[0053] Furthermore, as shown in FIG. 6, one or both of the first electrode portion 21 and the second electrode portion may have one or more holes formed therein. With this configuration, it is possible to reliably impregnate the liquid holding portion 25 with the target substance (water).

[0054] In the thawing / solidification sensor 10 of this embodiment, the sensor unit 11 and the determination unit 16 may be placed on the same substrate, as shown in Fig. 7. In this case, the thawing / solidification sensor 10 can be made smaller and easier to install. Note that a glass epoxy substrate or the like can be used as the substrate.

[0055] Furthermore, in the melting / freezing sensor 10 of this embodiment, the determination unit 16 may be configured to emit an alarm signal depending on the determination result of a change in the solid / liquid state of the target substance (water). By appropriately emitting an alarm signal depending on the freezing or thawing of the target substance, or the coexistence state of solid and liquid, it is possible to notify the change in the solid / liquid state of the target substance. [Example]

[0056] The results of confirmation experiments carried out to confirm the effects of the present invention will be described below.

[0057] The liquid holder was a rectangular plate of nonwoven fabric (1.5 cm x 5 cm, thickness 0.1 mm, 30 g / m 2 In addition, two copper plates (1 cm × 5 cm, thickness 70 μm) were prepared as the first electrode portion and the second electrode portion. The melting / solidification sensor element was constructed by laminating the first electrode part and the second electrode part (two copper plates) via the liquid holding part (nonwoven fabric).

[0058] Then, the liquid holding portion (nonwoven fabric) was impregnated with water, and the first electrode portion and the second electrode portion were connected to a resistance meter. By cooling this melting-freezing sensor element, the water impregnated in the liquid holding part (nonwoven fabric) was solidified, and the change in electrical resistance between the first electrode part and the second electrode part was measured. The measurement results are shown in Figure 8.

[0059] As shown in FIG. 8, it is confirmed that the electrical resistance value increases as the solidification of the water impregnated into the liquid holding portion (nonwoven fabric) progresses and the solid ratio increases. From the above, it has been confirmed that the present invention makes it possible to reliably detect a change in the state between solid and liquid in a target substance that is conductive in the liquid state. [Explanation of symbols]

[0060] 10 Melting / Freezing Sensor 11 Sensor section 12 Support member 16 Judgment section 20, 120 Melting / freezing sensor element 21, 121 1st electrode part 22, 122 2nd electrode part 25 Liquid holding part

Claims

1. A melting / freezing sensor element for detecting a change between a solid and a liquid state in a target substance that is conductive in a liquid state, a liquid holding portion in which the target substance in a liquid state is impregnated and held, and a first electrode portion and a second electrode portion disposed via the liquid holding portion; A melting / solidification sensor element characterized by detecting a change in the solid and liquid state of the target substance held in the liquid holding portion by an electrical signal generated between the first electrode portion and the second electrode portion.

2. 2. The melting / solidification sensor element according to claim 1, wherein the first electrode portion and the second electrode portion are made of the same material.

3. 2. The melting / solidification sensor element according to claim 1, wherein the first electrode portion and the second electrode portion are made of different metal materials.

4. 2. The melting / freezing sensor element according to claim 1, wherein the liquid holding portion is made of one or more of paper, thread, nonwoven fabric, cloth, and water-absorbing polymer.

5. 2. The fusion / freezing sensor element according to claim 1, wherein the liquid holding portion protrudes outward from between the first electrode portion and the second electrode portion.

6. A melting / freezing sensor that detects a change in the state between solid and liquid in a target substance that is conductive in a liquid state, 10. A thawing / solidification sensor comprising: a sensor unit in which the thawing / solidification sensor element according to claim 1 is disposed; a support member for supporting the sensor unit; and a determination unit for determining a change in the solid / liquid state of the target substance held in the liquid holding unit from an electrical signal generated between the first electrode unit and the second electrode unit.

7. A melting / freezing sensor that detects a change in the state between solid and liquid in a target substance that is conductive in a liquid state, 4. A thawing / solidification sensor comprising: a sensor unit in which a plurality of thawing / solidification sensor elements according to claim 3 are arranged; a support member for supporting the sensor unit; and a determination unit for determining a change in the solid / liquid state of the target substance held in the liquid holding unit from an electrical signal generated between the first electrode unit and the second electrode unit.

8. 8. The melting / freezing sensor according to claim 6, wherein the determining unit and the sensor unit are disposed on the same substrate.

9. 8. The melting / freezing sensor according to claim 6, wherein the determination unit determines a change in the coexistence state of the solid and liquid of the target substance from a change in an electrical signal generated between the first electrode unit and the second electrode unit.

10. 8. The melting / freezing sensor according to claim 6, wherein the determining unit issues an alarm signal in response to a determination result of a change in the state of the target substance between solid and liquid.

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