Liquid detecting sensor element and liquid detecting sensor

Abstract

A liquid detecting sensor element (20) according to the present invention detects a change of state of a target substance between a solid and a liquid, or a change of state of a target substance between dry and wet, the liquid detecting sensor element being characterized by including a liquid holding portion (25) into which the target substance in a liquid state is impregnated and held, and a first electrode portion (21) and a second electrode portion (22) which are arranged with the liquid holding portion (25) interposed therebetween, wherein the liquid holding portion (25) consists of an electrically conductive fiber body or an electrical-conductor-containing fiber body obtained by dispersing an electrical conductor in an insulating fiber body.

Description

Liquid detection sensor element and liquid detection sensor

[0001] This 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. This application claims priority to Japanese Patent Application No. 2024-057133, filed on March 29, 2024, the contents of which are incorporated herein by reference.

[0002] In snowy regions such as mountainous areas, avalanches can occur as temperatures rise. In snowy regions, avalanches can cut off transportation such as railroads and roads. Furthermore, avalanches can destroy infrastructure such as power lines, gas pipes, and water pipes, significantly affecting the living environment.

[0003] Here, the cause 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 snow. Snow falling from the roofs of structures also causes aquifers to form in the snow layer, causing avalanches. Furthermore, repeated melting and refreezing of snow on the surface of snow causes large granular snow crystals, and when new snow accumulates on top of this, a weak layer that can serve as 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 by detecting snowmelt at any depth, including the surface of the snow layer, and the formation of aquifers within the snow layer. That is, detecting the change of state of snow (solid) to water (liquid) on the surface or within the snow layer is sufficient. It is also effective to detect wet conditions due to rainfall, which increases the risk of avalanches and falling snow, and freezing due to a drop in temperature. For example, when storing and transporting products that require temperature control, such as frozen goods, it is necessary to perform temperature control to prevent the frozen goods from melting. Here, detecting the change of state of ice (solid) to water (liquid) enables temperature control.

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

[0006] Japanese Patent Application Laid-Open No. 07-020074 Japanese Patent Application Laid-Open No. 2000-284065 Japanese Patent Application Laid-Open No. 2004-028617 Japanese Patent Application Laid-Open No. 2003-232687 Japanese Patent No. 5547861

[0007] Recently, attempts have been made to utilize information and communication technology (the Internet) to perform unmanned avalanche and snowfall detection and temperature control. The sensors disclosed in Patent Documents 1-3 cannot detect the presence of water between a pair of electrodes, which could prevent accurate detection of aquifer formation. Furthermore, Patent Documents 4 and 5 require confirmation of color changes, making remote detection difficult.

[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.

[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 the first aspect of the present invention, the liquid detection sensor element includes a liquid holding portion in which the target substance in a liquid state is impregnated and held, thereby enabling the target substance to 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 having a conductor dispersed in an insulating fiber. 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. Furthermore, when the liquid holding portion is a conductor-containing fiber, the liquid holding portion is pre-impregnated with the target substance in a liquid state. When the target substance impregnated in the liquid holding portion changes state from a liquid state to a solid state or vice versa, a change in volume occurs, changing the dispersion state of the conductor in the liquid holding portion (conductor-containing fiber), thereby changing the electrical resistance of the liquid holding portion. 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 holder can be configured to contact the target substance in a solid state when it is dry, and when the target substance melts and becomes liquid, the target substance in a solid state can be impregnated into the liquid holder. This causes the liquid holder to swell, changing the dispersion state of the conductor in the liquid holder (conductor-containing fiber) or changing the network state of the conductive fiber, resulting in a change in the electrical resistance of the liquid holder. Conversely, electrical resistance can also change when the target substance in a liquid state flows out of the liquid holder or when the target substance dries due to evaporation, etc. By detecting the electrical signal accompanying the above-mentioned change in electrical resistance, it is possible to accurately and reliably detect the state change (melting) of the target substance from solid to liquid.

[0012] A liquid detection sensor element according to a second aspect of the present invention is characterized in that, in the liquid detection sensor element according to the first aspect, the insulating fibrous body is a mixture of one or more of insulating paper, thread, nonwoven fabric, and cloth. According to the liquid detection sensor element according to the second aspect of the present invention, the insulating fibrous body is a mixture of one or more of insulating paper, thread, nonwoven fabric, and cloth. 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 these papers, threads, nonwoven fabrics, and cloths expands and contracts in response to a change in volume of the impregnated target substance or swelling due to the liquid target substance. Therefore, when the target substance changes state between the liquid and solid states and changes volume, or when the liquid target substance is impregnated, the dispersion state of the conductor changes significantly, making it possible to easily detect an electrical signal associated with a change in electrical resistance. Furthermore, because the sensor element is made of paper, thread, nonwoven fabric, or cloth, it can be easily manufactured over a large area and over a long distance, enabling wide-range detection. Furthermore, because the sensor element is made of a fibrous body, it is flexible and can be easily installed in various shapes.

[0013] A liquid detection sensor element of Aspect 3 of the present invention is characterized in that the conductor is a carbon nanotube in the liquid detection sensor element of Aspect 1 or Aspect 2. According to the liquid detection sensor element of Aspect 3 of the present invention, the conductor is a carbon nanotube, and therefore it is possible to form the conductor-containing fibrous body by incorporating carbon nanotubes into the insulating fibrous body.

[0014] A liquid detection sensor element of Aspect 4 of the present invention is characterized in that the conductor is an organic conductive material in the liquid detection sensor element of Aspect 1 or Aspect 2. According to the liquid detection sensor element of Aspect 4 of the present invention, the conductor is an organic conductive material, and therefore it is possible to form the conductor-containing fibrous body by incorporating an organic conductive material into an insulating fibrous body.

[0015] A liquid detection sensor element of Aspect 5 of the present invention is characterized in that, in the liquid detection sensor element of Aspect 1 or Aspect 2, 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 fiber body can be formed by incorporating nanotubes or nanowires into an insulating fiber body.

[0016] A 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, thread, nonwoven fabric, and cloth. According to the liquid detection sensor element of Aspect 6 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 such as metal, carbon, conductive polymer, and conductive inorganic material 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, a sensor unit having a liquid detection sensor element of any one of Aspects 1 to 6 of the present invention disposed thereon and a support member for supporting the sensor unit are provided, so that the liquid detection sensor element can be disposed at any position, and it is possible to detect drying, wetting, melting, and solidification of a target substance at a predetermined position. In addition, a determination unit is provided that determines a change in the state of the target substance between solid and liquid, which is impregnated and held in the liquid holding unit, from an electrical signal generated between the first electrode unit and the second electrode unit, so that it is possible to reliably detect drying, wetting, melting, and solidification of the target substance.

[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.

[0020] FIG. 1 is a schematic explanatory diagram of a liquid detection sensor element according to a first embodiment of the present invention, showing a case where the target substance impregnated in the liquid holding portion is in a liquid state. FIG. 1 is a schematic explanatory diagram of a liquid detection sensor element according to a first embodiment of the present invention, showing a case where the target substance impregnated in the liquid holding portion is in a solid state. FIG. 2 is a schematic explanatory diagram of a liquid holding portion (conductor-containing fibrous body) of a liquid detection sensor element according to a first embodiment of the present invention, showing a case where the target substance impregnated in the liquid holding portion is in a liquid state. FIG. 3 is a schematic explanatory diagram of a liquid detection sensor according to an embodiment of the present invention. FIG. 4 is a schematic explanatory diagram of a liquid holding portion (conductor-containing fibrous body) of a liquid detection sensor element according to a second embodiment of the present invention, showing a case where the target substance impregnated in the liquid holding portion is in a dry state. FIG. 5 is a schematic explanatory diagram of a liquid detection sensor according to another embodiment of the present 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 in the state between solid and liquid of a target substance, which undergoes a volume change when it changes state between the liquid and solid states. In this embodiment, the target substance is water, which exists in nature, and the purpose is to detect the formation of an aquifer due to melting snow in a snow layer. Note that the volume of water increases when it changes state (freezes) from liquid (water) to solid (snow or ice).

[0023] 1A and 1B, a liquid detection sensor element 20 according to an embodiment of the present invention will be described. As shown in Figs. 1A and 1B, the liquid detection sensor element 20 according to 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 that are disposed 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 Figures 2A and 2B, 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 fibrous body) so that it is hydrophilized to promote water impregnation.

[0026] Here, the insulating fiber body 26 is preferably made of one material selected from, for example, insulating paper, thread, nonwoven fabric, cloth, etc. Furthermore, 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 complexes (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, and Bi nanowires. ２ Te ３ Examples of the nanowire include nanotubes or nanowires made of silicon semiconductors.

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

[0029] Instead of the insulating fiber body 26, a conductive fiber body using 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, another conductor may be dispersed in the conductive fiber body, or no conductor may be dispersed in the conductive fiber body.

[0030] In the liquid detection sensor element 20 of this embodiment, the volume change 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 changes. That is, when the volume increases, as shown in Fig. 2B, 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 the liquid holding portion 25. In the liquid holding portion 25 made of a conductor-containing fibrous material 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 FIG. 3 , the liquid detection sensor 10 of this embodiment includes a sensor unit 11 in which the liquid detection sensor element 20 of this embodiment is disposed, a support member 12 that supports the sensor unit 11, and a determination unit 16 that determines a change in the state of the target substance held in the liquid holding unit 25 between solid (snow or ice) and liquid (water) based on an electrical signal generated between the first electrode unit 21 and the second electrode unit 22. For example, a change in the state between solid and liquid may be determined to have occurred when an electrical signal is detected in which the electrical resistance value changes by 10% or more, preferably by 20% to 50%. Alternatively, a change in the state of the target substance between solid and liquid may be determined to have occurred when an electrical signal (electrical resistance value) in which the electrical resistance value changes by 1% or more, preferably by 2% to 10%, is detected.

[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] Below, we will explain a method for detecting the occurrence of an aquifer in a snow layer and freezing due to a drop in temperature caused by moisture due to rainfall using the liquid detection sensor element 20 and liquid detection sensor 10 of this embodiment. First, a liquid detection sensor element 20 is prepared in a state where the target substance is not impregnated in the liquid holding portion 25. Next, the liquid holding portion 25 is impregnated with a target substance (water) in a liquid state, 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 unit 11. Then, the liquid detection sensor 10 of this embodiment is disposed so that the sensor unit 11 is located at a predetermined position in the snow layer.

[0035] When a water layer is formed in the snow layer due to a 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, the determination unit 16 changes the electrical resistance in the liquid holding portion 25 due to the volume change between the solid state (snow or ice) and the liquid state (water). This change in electrical resistance is detected as an electrical signal generated between the first electrode portion 21 and the second electrode portion 22, and it is detected that the target substance in a solid state (snow or ice) has melted and become a liquid state (water). This detects the formation of an aquifer in the snow layer, and determines the risk of an avalanche or falling snow.

[0036] According to the liquid detection sensor element 20 of the embodiment configured as described above, it has a liquid holding portion 25 that impregnates 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 an 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 the 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, if the insulating fiber 26 of the conductor-containing fiber constituting the liquid holding portion 25 is any one of paper, thread, nonwoven fabric, and cloth, the conductor-containing fiber can be easily produced by incorporating a conductor into the paper, thread, nonwoven fabric, or cloth. Alternatively, the conductive fiber can be made of paper, thread, nonwoven fabric, or cloth using a conductive material. Furthermore, since any one of these types of paper, thread, nonwoven fabric, and 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 changes volume, the dispersion state of the conductor 27 changes significantly, making it possible to easily detect an electrical signal associated with a change in electrical resistance.

[0039] 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 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 an 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 that constitutes 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] The liquid detection sensor 10 of this embodiment includes a sensor unit 11 in which the liquid detection sensor element 20 of this embodiment is disposed, and a support member 12 that supports the sensor unit 11. This allows the sensor unit 11 (liquid detection sensor element 20) to be disposed at any position, making it possible to detect the freezing and melting of a target substance at a predetermined position. Furthermore, the liquid detection sensor 10 includes a determination unit 16 that determines a change in the state of the target substance held in the liquid holding unit 25 between a solid state (snow or ice) and a liquid state (water) based on an electrical signal generated between the first electrode unit 21 and the second electrode unit 22, making it possible to reliably detect the melting and freezing 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.In addition, 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, a description will be given of another method of using the liquid detection sensor element 20 and the liquid detection sensor 10 according to an embodiment of the present invention. In this embodiment, as in the first embodiment, the target substance is water that exists in nature, and the generation of an aquifer due to melting snow in a snow layer is detected.

[0046] In the liquid detection sensor element 20 and the liquid detection sensor 10 of this embodiment, the liquid holding portion 25 is not impregnated with the target substance and is used in a dry state. That is, the liquid detection sensor element 20, whose liquid holding portion 25 is not impregnated with the target substance (water), is placed in 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 becomes a liquid state (water), the target substance (water) in a liquid state is impregnated into and held in the liquid holding portion 25.

[0047] 4A and 4B, the conductor-containing fibrous material constituting 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 of the liquid holding portion 25. In the liquid holding portion 25 made of a conductor-containing fibrous material in which carbon nanotubes are dispersed in paper, the electrical resistance increased by 30% due to the impregnation of the target substance (water) in a liquid state.

[0048] By detecting the electrical signal accompanying the above-described change in electrical resistance, it is possible to accurately and reliably detect changes between dry and wet states, as well as changes in the state (melting) of the target substance from a solid (snow or ice) to a liquid (water). For example, a change in electrical resistance of 10% or more, preferably 20% to 50%, can be detected to determine that a change between dry and wet states has occurred. 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 avalanches or snowfall. Furthermore, by disposing the sensor on the snow surface, it is possible to detect the melting and refreezing of snow, thereby predicting the occurrence of granular snow, which occurs when crystals grow larger due to repeated melting and refreezing. Furthermore, when new snow accumulates on granular snow, it is possible to predict the occurrence of a weak layer at the interface, which can 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 causes 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 state of the snow layer can be detected by detecting the change from the liquid state (water) held in the liquid holding portion 25 to a solid state (ice), allowing for the detection of the accumulation of new snow due to snowfall. 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. When new snow accumulates on granular snow, the occurrence of a weak layer at the interface that can cause an avalanche can be predicted. By installing a thermometer, more detailed detection of dry, wet, solid, and liquid states becomes possible.

[0050] The insulating fiber body 26 may be replaced with a conductive fiber body made of metal, carbon, a conductive polymer, or a conductive inorganic material. 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 embodiment and can be modified as appropriate within the scope of the technical concept of the invention. For example, in this embodiment, a liquid detection sensor has been described as detecting the formation of an aquifer in a snow layer, but the present invention 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 a change in state between a liquid state and a solid state.

[0052] In addition, in this embodiment, a plurality of sensor units are provided, but this is not limiting, and only one sensor unit may be provided, as shown in Fig. 5. Furthermore, in this embodiment, water is used as an example of the target substance, but this is not limiting, and other target substances may be used.

[0053] REFERENCE SIGNS LIST 10 Liquid detection sensor 11 Sensor section 12 Support member 16 Determination section 20 Liquid detection sensor element 21 First electrode section 22 Second electrode section 25 Liquid holding section

Claims

1. A liquid detection sensor element that detects a change in the state of a target substance between solid and liquid, or between dry and wet states of a target substance, comprising 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, wherein 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.

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

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

5. 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. A 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. A liquid detection sensor comprising: a sensor section in which a liquid detection sensor element according to any one of claims 1 to 6 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, 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