Liquid detection sensor element, and liquid detection sensor

Abstract

To provide a liquid detection sensor element with a simple structure capable of precisely detecting a change in the solid and liquid state of a target substance, or changes in the dry and wet state of the target substance, and a liquid detection sensor.SOLUTION: A liquid detection sensor element 20 is a sensor element that detects changes in the state of a target substance between solid and liquid, or changes in the state of the target substance between dry and wet. The sensor element includes: a liquid holding portion 25 in which the target substance in a liquid state is impregnated and held; and a first electrode unit 21 and a second electrode unit 22 that are disposed via the liquid holding unit 25. The liquid holding unit 25 is composed of a conductive fiber body or a conductive-containing fiber body in which a conductor is dispersed in an insulating fiber body.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a liquid detection sensor element and a liquid detection sensor that detect a change in the state of a target substance between solid and liquid, or between dry and wet states of the target substance. [Background technology]

[0002] In snowy mountainous regions, avalanches can occur as temperatures rise, cutting off railroads, roads, and other transportation services. 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 that aquifers are formed 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 of the snow piles up, it melts and refreezes repeatedly, causing the crystals to 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 falling snow is effective when 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 from snow (solid) to water (liquid) on the surface or within the snow layer. It is also effective to detect wet conditions due to rainfall, which increase the risk of avalanches and falling snow, and freezing due to a drop in temperature. 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] Patent No. 5547861 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 liquid detection sensor element and a liquid detection sensor that have a simple structure and are capable of accurately detecting changes in the state of a target substance between solid and liquid, or between dry and wet states of the target substance. [Means for solving the problem]

[0009] In order to solve the above problems, the liquid detection sensor element of aspect 1 of the present invention is a liquid detection sensor element that detects a change in the state of a target substance between solid and liquid, or a change in the state of a target substance between dry and wet, and is characterized in that it has 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 the liquid holding portion is composed of a conductive fiber body or a conductor-containing fiber body in which a conductor is dispersed in an insulating fiber body.

[0010] According to the liquid detection sensor element of aspect 1 of the present invention, the liquid detection sensor element has a liquid holding portion in which the target substance in a liquid state is impregnated and held, so that the target substance can be reliably disposed between the first electrode portion and the second electrode portion. The liquid holding portion is a conductive fiber or a conductor-containing fiber in which a conductor is dispersed in an insulating fiber, so that, for example, when the liquid holding portion is a conductive fiber, a change in the state of the target substance impregnated in the liquid holding portion changes the network state of the conductive fiber, thereby changing the electrical resistance of the liquid holding portion. Also, when the liquid holding portion is a conductor-containing fiber, the liquid holding portion is pre-impregnated with a target substance in a liquid state, and when the target substance impregnated in the liquid holding portion changes state from a liquid state to a solid state or vice versa and changes in volume, the dispersion state of the conductor in the liquid holding portion (conductor-containing fiber) changes, and the electrical resistance of the liquid holding portion changes. By detecting the electrical signal accompanying the above-mentioned change in electrical resistance, it is possible to accurately and reliably detect the state change of the target substance from dry to wet, from wet to dry, from solid to liquid (melting), or from liquid to solid (solidification).

[0011] Alternatively, the liquid holding portion may be arranged in a dry state so as to come into contact with the target substance in a solid state, and when the target substance melts and becomes liquid, the target substance in a solid state may be impregnated into the liquid holding portion. This causes the liquid holding portion to swell, changing the dispersion state of the conductor in the liquid holding portion (conductor-containing fiber body), or changing the network state of the conductive fiber body, thereby changing the electrical resistance of the liquid holding portion. Conversely, the electrical resistance may also change when the target substance in a liquid state flows out of the liquid holding portion or when the target substance dries due to evaporation or the like. By detecting the electrical signal accompanying the change in electrical resistance described above, it is possible to accurately and reliably detect the change in state (melting) of the target substance from solid to liquid.

[0012] The liquid detection sensor element of aspect 2 of the present invention is characterized in that, in the liquid detection sensor element of aspect 1, the insulating fiber body is one or a mixture of two or more of insulating paper, yarn, nonwoven fabric, and cloth. According to the liquid detection sensor element of the second aspect of the present invention, the insulating fibrous body is one or a mixture of two or more of insulating paper, thread, nonwoven fabric, and cloth, and therefore, a conductor-containing fibrous body can be easily produced by incorporating a conductor into the insulating paper, thread, nonwoven fabric, or cloth. Furthermore, any one of the papers, threads, nonwoven fabrics, and cloths expands and contracts in response to a change in the volume of the target substance impregnated therein or swelling due to the target substance in a liquid state. Therefore, when the target substance changes state between a liquid state and a solid state and changes in volume, or when the target substance in a liquid state is impregnated, the dispersion state of the conductor changes significantly, and it becomes possible to easily detect an electrical signal accompanying a change in electrical resistance. In addition, because they are made of paper, thread, nonwoven fabric, or cloth, they can be easily made into large areas and long distances, enabling detection over a wide range.Furthermore, because they are fibrous, they are flexible and can be easily installed in a variety of shapes.

[0013] A liquid detection sensor element according to a third aspect of the present invention is the liquid detection sensor element according to the first or second aspect, characterized in that the conductor is a carbon nanotube. According to the liquid detection sensor element of aspect 3 of the present invention, the conductor is a carbon nanotube, and therefore, the conductor-containing fibrous body can be formed by incorporating carbon nanotubes into an insulating fibrous body.

[0014] A liquid detection sensor element according to a fourth aspect of the present invention is the liquid detection sensor element according to the first or second aspect, characterized in that the conductor is an organic conductive material. According to the liquid detection sensor element of aspect 4 of the present invention, the conductor is an organic conductive material, and therefore, the conductor-containing fibrous body can be constructed by incorporating an organic conductive material into an insulating fibrous body.

[0015] A liquid detection sensor element according to a fifth aspect of the present invention is characterized in that in the liquid detection sensor element according to the first or second aspect, the conductor is a nanotube or nanowire made of a compound semiconductor or a silicon semiconductor. According to the liquid detection sensor element of aspect 5 of the present invention, the conductor is a nanotube or nanowire made of a compound semiconductor or a silicon semiconductor, so that the conductor-containing fibrous body can be constructed by incorporating nanotubes or nanowires into an insulating fibrous body.

[0016] The liquid detection sensor element of aspect 6 of the present invention is characterized in that, in the liquid detection sensor element of aspect 1 or aspect 2, the conductive fiber body is one or a mixture of two or more of conductive paper, yarn, nonwoven fabric, and cloth. According to the liquid detection sensor element of the sixth aspect of the present invention, the conductive fiber body is one or a mixture of two or more of conductive paper, thread, nonwoven fabric, and cloth, so that the liquid detection sensor element can be easily produced. Note that conductive fibers of metal, carbon, conductive polymer, conductive inorganic material, etc. can be used as the material for the conductive paper, thread, nonwoven fabric, and cloth.

[0017] The liquid detection sensor of aspect 7 of the present invention is characterized by comprising a sensor section in which a liquid detection sensor element of any one of aspects 1 to 6 of the present invention is arranged, a support member that supports the sensor section, and a determination section that determines a change in the solid / liquid state of the target substance impregnated and held in the liquid holding section from an electrical signal generated between the first electrode section and the second electrode section.

[0018] According to the liquid detection sensor of aspect 7 of the present invention, it is equipped with a sensor unit in which a liquid detection sensor element of any one of aspects 1 to 6 of the present invention is arranged, and a support member that supports this sensor unit, so that the liquid detection sensor element can be arranged at any position, and it becomes possible to detect drying and wetting, melting and solidification of the target substance at a specified position. In addition, the device is equipped with a judgment unit that judges the change in the solid and liquid state of the target substance impregnated and 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 drying, wetting, melting, and solidification of the target substance. [Effects of the Invention]

[0019] According to the present invention, it is possible to provide a liquid detection sensor element and a liquid detection sensor that have a simple structure and are capable of accurately detecting changes in the state of a target substance between solid and liquid, or between dry and wet states of the target substance. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a schematic explanatory diagram of a liquid detection sensor element according to a first embodiment of the present invention; [Figure 2] 1 is a schematic explanatory diagram of a liquid holding portion (electrical conductor-containing fiber body) of a liquid detection sensor element according to a first embodiment of the present invention. FIG. [Figure 3] 1 is a schematic explanatory diagram of a liquid detection sensor according to an embodiment of the present invention; [Figure 4] FIG. 10 is a schematic explanatory diagram of a liquid holding portion (electrical conductor-containing fiber body) of a liquid detection sensor element according to a second embodiment of the present invention. [Figure 5] FIG. 10 is a schematic explanatory diagram of a liquid detection sensor according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] 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.

[0022] (First embodiment) The liquid detection sensor element 20 and the liquid detection sensor 10 of this embodiment detect a change between the solid and liquid states of a target substance, which undergoes a volume change when the substance changes between the liquid state and the solid state. In this embodiment, the target substance is water, which exists in nature, and the system detects the occurrence of an aquifer due to melting snow in a snow layer. Note that water increases in volume when it changes state (solidifies) from liquid (water) to solid (snow or ice).

[0023] A liquid detection sensor element 20 according to an embodiment of the present invention will be described with reference to FIG. As shown in Figure 1, the liquid detection sensor element 20 of this embodiment has a liquid holding portion 25 that is impregnated with and holds a target substance (water in this embodiment) that undergoes a volume change when changing between a liquid state and a solid state, and a first electrode portion 21 and a second electrode portion 22 arranged via the liquid holding portion 25.

[0024] The first electrode portion 21 and the second electrode portion 22 may be made of any conductive material, such as metal materials such as copper and aluminum, carbon-based materials, inorganic semiconductor materials, organic semiconductor materials, etc.

[0025] The liquid holding portion 25 is impregnated with and holds the target substance. As shown in FIG. 2, the liquid holding portion 25 is a conductor-containing fibrous body in which conductors 27 are dispersed in an insulating fibrous body 26 . In this embodiment, since the target substance is water, it is preferable to configure the liquid holding portion 25 (conductor-containing fiber body) so as to promote water impregnation by performing a hydrophilic treatment.

[0026] Here, the insulating fiber body 26 is preferably made of one material selected from insulating paper, thread, nonwoven fabric, cloth, and the like. Examples of the conductor 27 include carbon nanotubes, organic conductive materials, nanotubes or nanowires made of compound semiconductors or silicon semiconductors, noble metal compounds, carbon materials, and metal materials.

[0027] Examples of organic conductive materials include PEDOT-based materials (PEDOT:PSS, PEDOT:Tos, etc.), π-conjugated nickel complex-based materials (poly(nickel-ethylenetetrathiolate)), and N-DMBI-based materials (N,N-dimethyl-2-phenyl-2,3-dihydro-1H-benzoimidazole). Examples of nanotubes and nanowires made of compound semiconductors or silicon semiconductors include boron nitride nanotubes, Si nanowires, Bi2Te3 nanowires, and nanotubes or nanowires made of silicon semiconductors.

[0028] Examples of the noble metal compound include copper compounds, silver compounds, gold compounds, platinum compounds, etc. Specifically, compounds of noble metal elements (Cu, Ag, Au, Pt) with S, Se, or Te are preferred. Examples of the carbon material include carbon black and graphite. Examples of the metal material include Bi, Co, Fe, and Ni.

[0029] Instead of the insulating fiber body 26, metal, carbon, conductive polymer, conductive inorganic material Using The conductive fiber body may be a conductive fibrous body. The conductive fibrous body may be conductive paper, thread, nonwoven fabric, or cloth. In this case, the conductive fibrous body may have another conductor dispersed therein, or may not have any conductor dispersed therein.

[0030] In the liquid detection sensor element 20 of this embodiment, the change in volume between when the target substance held in the liquid holding portion 25 is in a solid state (snow or ice) and when it is in a liquid state (water) changes the dispersion state of the conductors 27 in the conductor-containing fibrous body that constitutes the liquid holding portion 25, and accordingly, the electrical resistance value of the liquid holding portion 25 also changes. That is, when the volume increases, as shown in FIG. 2(b), the dispersed conductors 27 move away from each other, the number of contact points between the conductors 27, 27 decreases, and the electrical resistance increases.

[0031] Therefore, by detecting this change in electrical resistance, it is possible to detect a change in the state of the target substance held in liquid holding portion 25. In addition, in the liquid holding portion 25 made of a conductor-containing fibrous body in which carbon nanotubes are dispersed in paper, the electrical resistance decreased by 3% when the target substance changed state from a solid state (snow or ice) to a liquid state (water).

[0032] As shown in Figure 3, the liquid detection sensor 10 of this embodiment comprises a sensor section 11 in which the liquid detection 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 the change in state between the solid (snow or ice) and liquid (water) of the target substance held in the liquid holding section 25 from the electrical signal generated between the first electrode section 21 and the second electrode section 22.

[0033] In this embodiment, the purpose is to detect the occurrence of an aquifer in the snow layer and freezing due to a drop in temperature caused by moisture due to rainfall, so the support member 12 is rod-shaped so that it can be installed in the snow layer, and sensor units 11 are arranged at multiple points along the length of the support member 12.

[0034] A method for detecting the occurrence of an aquifer in a snow layer and freezing due to a drop in temperature caused by wetness due to rainfall using the liquid detection sensor element 20 and the liquid detection sensor 10 of this embodiment will be described below. First, the liquid detection sensor element 20 is prepared in a state where the liquid holding portion 25 is not impregnated with the target substance. Next, the liquid-state target substance (water) is impregnated into the liquid holding portion 25, and the target substance is solidified into a solid state (ice). The liquid detection sensor element 20 in this state is disposed in the sensor portion 11. Then, the liquid detection sensor 10 of this embodiment is disposed so that the sensor portion 11 is located at a predetermined position in the snow layer.

[0035] 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 liquid detection sensor element 20 melts and becomes a liquid state (water). Here, in determination unit 16, a change in volume between the solid state (snow or ice) and the liquid state (water) causes a change in electrical resistance in liquid holding unit 25. This change in electrical resistance is detected as an electrical signal generated between first electrode unit 21 and second electrode unit 22, and it is detected that the target substance in the solid state (snow or ice) has melted and become in the liquid state (water). This will allow the formation of aquifers in the snow layer to be detected, and determine the risk of avalanches or falling snow.

[0036] According to the liquid detection sensor element 20 of the embodiment configured as described above, the liquid holding portion 25 is impregnated with and holds the target substance, which undergoes a volume change when the state changes between the liquid state and the solid state, so that the target substance can be reliably disposed between the first electrode portion 21 and the second electrode portion 22.

[0037] Furthermore, since the liquid holding portion 25 is composed of a conductor-containing fibrous body in which conductors 27 are dispersed in insulating fibrous body 26, or a conductive fibrous body, when the target substance (water) changes state between a liquid state (water) and a solid state (snow or ice) and its volume changes, the dispersion state of conductors 27 inside the conductor-containing fibrous body and the network state of the conductive fibrous body change, causing a change in electrical resistance in the liquid holding portion 25. By detecting an electrical signal accompanying this change in electrical resistance, it becomes possible to accurately and reliably detect the state change (melting) of the target substance (water) from a solid state (snow or ice) to a liquid state (water) or the state change (solidification) from a liquid state (water) to a solid state (snow or ice).

[0038] In the liquid detection sensor element 20 of this embodiment, when the insulating fiber body 26 of the conductor-containing fiber body constituting the liquid holding portion 25 is any one of paper, thread, nonwoven fabric, and cloth, the conductor-containing fiber body can be easily produced by incorporating a conductor into the paper, thread, nonwoven fabric, or cloth. Alternatively, the conductive fiber body can be made of paper, thread, nonwoven fabric, or cloth using a conductive substance. Furthermore, since any one of these types of paper, thread, nonwoven fabric, or cloth expands and contracts in response to changes in the volume of the target substance impregnated therein, when the target substance changes state between a liquid state (water) and a solid state (snow or ice) and its volume fluctuates, the dispersion state of the conductor 27 changes significantly, making it possible to easily detect the electrical signal accompanying the change in electrical resistance.

[0039] In the liquid detection sensor element 20 of this embodiment, if the conductor of the conductor-containing fibrous body constituting the liquid holding portion 25 is a carbon nanotube, it is possible to form a conductor-containing fibrous body (liquid holding portion 25) by incorporating carbon nanotubes into the insulating fibrous body 26.

[0040] In the liquid detection sensor element 20 of this embodiment, if the conductor of the conductor-containing fibrous body that constitutes the liquid holding portion 25 is an organic conductive material, it is possible to form a conductor-containing fibrous body (liquid holding portion 25) by incorporating the organic conductive material into the insulating fibrous body 26.

[0041] Furthermore, in the liquid detection sensor element 20 of this embodiment, if the conductor of the conductor-containing fibrous body constituting the liquid holding portion 25 is a nanotube or nanowire made of a compound semiconductor or a silicon semiconductor, it is possible to form a conductor-containing fibrous body (liquid holding portion 25) by incorporating nanotubes or nanowires into the insulating fibrous body 26.

[0042] In the liquid detection sensor element 20 of this embodiment, instead of the conductor-containing fibrous material that constitutes the liquid holding portion 25, the conductive fibrous material can be made from one or more of metal, carbon, conductive polymer, and conductive inorganic material, such as paper, thread, nonwoven fabric, or cloth, and the conductive fibrous material can be made from this conductive paper, thread, nonwoven fabric, or cloth.

[0043] According to the liquid detection sensor 10 of this embodiment, it is equipped with a sensor section 11 in which the liquid detection sensor element 20 of this embodiment is arranged, and a support member 12 that supports this sensor section 11, so that the sensor section 11 (liquid detection sensor element 20) can be arranged at any position, and it becomes possible to detect the solidification and melting of the target substance at a specified position. In addition, it is equipped with a judgment unit 16 that judges the change in state of the target substance held in the liquid holding unit 25 between a solid state (snow or ice) and a liquid state (water) 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.

[0044] Therefore, for example, by disposing this liquid detection sensor 10 in a snow layer, it is possible to detect the formation of an aquifer in the snow layer and determine the risk of avalanches or falling snow. Also, because it is possible to detect the melting and refreezing of snow, 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 granular snow, it is possible to predict the occurrence of a weak layer at the interface that could cause an avalanche.

[0045] (Second embodiment) Next, another method of using the liquid detection sensor element 20 and the liquid detection sensor 10 according to the embodiment of the present invention will be described. In this embodiment, as in the first embodiment, the target substance is water that exists in nature, and the purpose is to detect the formation of an aquifer due to melting snow in the snow layer.

[0046] In the liquid detection sensor element 20 and the liquid detection sensor 10 of this embodiment, the liquid holding portion 25 is used in a dry state without being impregnated with the target substance. That is, the liquid detection sensor element 20, in which the liquid holding portion 25 is not impregnated with the target substance (water), is placed so as to come into contact with the target substance (snow or ice) in a solid state. Then, when the target substance (snow or ice) in a solid state melts and turns into a liquid state (water), the target substance (water) in a liquid state is impregnated into and held in liquid holding portion 25.

[0047] As a result, as shown in Figure 4, the conductor-containing fibrous material that constitutes the liquid holding portion 25 swells, changing the dispersion state of the conductor 27 in the liquid holding portion 25 (conductor-containing fibrous material), and changing the electrical resistance in the liquid holding portion 25. In addition, in the liquid holding portion 25 made of a conductor-containing fibrous body in which carbon nanotubes are dispersed in paper, the electrical resistance increased by 30% when the liquid target substance (water) was impregnated.

[0048] By detecting the electrical signal accompanying the above-mentioned change in electrical resistance, it is possible to accurately and reliably detect changes in state between dry and wet states, as well as changes in state (melting) of the target substance from solid (snow or ice) to liquid (water). Therefore, for example, by disposing a liquid detection sensor 10 equipped with this liquid detection sensor element 20 in a snow layer, it is possible to detect the formation of an aquifer in the snow layer and determine the risk of an avalanche or falling snow. Also, by disposing it on the surface of the snow, it is possible to detect the melting and refreezing of snow, making it 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 could cause an avalanche.

[0049] Furthermore, by installing the liquid detection sensor element 20 on the surface of the snow layer in a dry state or at a higher location, rainfall will cause the liquid holding portion 25 to become wet, resulting in a change in electrical resistance. Furthermore, when rainfall turns to snow due to a drop in temperature, the liquid state (water) held in the liquid holding portion 25 can be detected to change to a solid state (ice), thereby detecting the state of the snow layer and detecting the accumulation of new snow due to snowfall. Because it is possible to detect the melting and refreezing of snow, it is possible to predict the occurrence of granular snow, which occurs when crystals grow larger due to repeated melting and refreezing. When new snow accumulates on granular snow, it is possible to predict the occurrence of a weak layer, the interface of which can cause an avalanche. By installing a thermometer, it is possible to detect dry, wet, solid, and liquid states in more detail.

[0050] Instead of the insulating fiber body 26, a conductive fiber body made of metal, carbon, a conductive polymer, or a conductive inorganic material may be used. The conductive fiber body may be conductive paper, thread, nonwoven fabric, or cloth. In this case, the conductive fiber body may have another conductor dispersed therein, or may not have a conductor dispersed therein.

[0051] 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. For example, in this embodiment, the sensor is described as a liquid detection 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 in state between a dry state and a wet state, or between a liquid state and a solid state.

[0052] 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 limitative, and as shown in FIG. 5, a configuration in which only one sensor unit is arranged may also be used. Furthermore, in this embodiment, the target substance has been described as water, but the target substance is not limited to water, and other target substances may be used. [Explanation of symbols]

[0053] 10 Liquid detection sensor 11 Sensor section 12 Support member 16 Judgment section 20 Liquid detection sensor element 21 1st electrode part 22 Second electrode part 25 Liquid holding part

Claims

1. A liquid detection sensor element that detects a change in the state of a target substance between solid and liquid, or a change in the state of a target substance between dry and wet, 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; The liquid detection sensor element is characterized in that the liquid holding portion is made of a conductive fiber body or a conductor-containing fiber body in which a conductor is dispersed in an insulating fiber body.

2. 2. The liquid detection sensor element according to claim 1, wherein the insulating fiber body is made of one or a mixture of two or more of insulating paper, thread, nonwoven fabric, and cloth.

3. 2. The liquid detection sensor element according to claim 1, wherein the conductor is a carbon nanotube.

4. 2. The liquid detection sensor element according to claim 1, wherein the conductor is an organic conductive material.

5. 2. The liquid detection sensor element according to claim 1, wherein the conductor is a nanotube or nanowire made of a compound semiconductor or a silicon semiconductor.

6. 2. The liquid detection sensor element according to claim 1, wherein the conductive fiber body is one or a mixture of two or more of conductive paper, thread, nonwoven fabric, and cloth.

7. 7. A liquid detection sensor comprising: a sensor section in which the liquid detection sensor element according to claim 1 is disposed; a support member that supports the sensor section; and a determination section that determines a change in the solid-liquid state of the target substance impregnated and held in the liquid holding section, or a change in the dry-wet state of the target substance, from an electrical signal generated between the first electrode section and the second electrode section.

Images