Sensor, detection system, and detection method

Abstract

To provide a sensor having different sensitivities according to positions.SOLUTION: A sensor 1 for detecting presence of liquid, the sensor comprises a first electrode 11 and a second electrode 12, where the first electrode and second electrode have a filamentous or strip-like structure and are juxtaposed in a direction crossing the longitudinal direction. At least one of the first electrode and second electrode includes a first portion 111 having a first surface area at a first position in the longitudinal direction, and a second portion 112 having a second surface area larger than the first surface area at a second position in the longitudinal direction, different from the first position.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to sensors, detection systems, and detection methods. [Background technology]

[0002] Patent Document 1 discloses that the magnitude of the non-contact area of ​​the electrode with the liquid is detected in an absorbing member by utilizing the magnitude of the parasitic resistance that changes depending on the size of the non-contact area of ​​the electrode with the liquid. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-166040 Summary of the Invention

[0004] The present inventors have discovered that when a sensor is used for an object, such as a diaper, that has a position where the presence of liquid is primarily detected and a position where it is preliminarily detected, it is effective to vary the sensitivity of the sensor depending on the position. One of the objects of the present disclosure is to provide a sensor whose sensitivity varies depending on the position, a detection system using the sensor, and a detection method.

[0005] According to one embodiment, the sensor comprises: A power generating device is provided which includes a first electrode and a second electrode and generates electric power between the first electrode and the second electrode. The presence of liquid , by the generated power A sensor for detecting the first electrode and the second electrode is a thread-like or strip-like structure arranged in a direction intersecting the longitudinal direction, and is used to detect a liquid present between the electrodes, and at least one of the first electrode and the second electrode has a first portion having a first surface area at a first position in the longitudinal direction, and a second portion having a second surface area larger than the first surface area at a second position in the longitudinal direction different from the first position.

[0006] According to one embodiment, the detection system detects the object to be detected. A first electrode and a second electrode are mounted on the device, and power is generated between the first electrode and the second electrode.The presence of liquid , by the generated power A system for detecting The presence of the liquid is detected by the generated electric power generated between the first electrode and the second electrode. the first electrode and the second electrode have a thread-like or strip-like structure and are arranged side by side in a direction intersecting the longitudinal direction, and at least one of the first electrode and the second electrode has a first portion having a first surface area at a first position in the longitudinal direction, and a second portion having a second surface area larger than the first surface area at a second position in the longitudinal direction different from the first position.

[0007] According to one embodiment, the detection method comprises: Generate power between the first electrode and the second electrode. The presence of liquid , by the generated power A method for detecting thread-like or band-like structures The aforementioned a first electrode and The aforementioned The second electrode is arranged in parallel in a direction intersecting the longitudinal direction, the first electrode and the second electrode being made of different materials, and when the first electrode comes into contact with a liquid present between the electrodes, power is generated between the electrodes when the liquid is present between the electrodes, and at least one of the first electrode and the second electrode has a first portion having a first surface area at a first position in the longitudinal direction, and a second portion having a second surface area larger than the first surface area at a second position in the longitudinal direction different from the first position, and detecting that the amount of generated power exceeds a threshold value, thereby detecting the presence of a predetermined amount of liquid, wherein the threshold value is greater than the maximum amount of power generated by the first portion and less than the maximum amount of power generated by the second portion.

[0008] Further details will be described in the following embodiments. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram of a detection system 100 according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view of the absorbing member main body taken along line MM in FIG. [Figure 3] FIG. 3 is a schematic diagram showing the configuration of the detection device. [Figure 4] FIG. 4 is a diagram showing the measurement results of the generated current of the sensor by the inventors. [Figure 5] FIG. 5 shows the results of measurements made by the inventors on the change in the charging voltage of a capacitor over time. [Figure 6] FIG. 6 is a diagram showing the measurement results of wireless signals obtained in an experiment conducted by the inventors using a detection system to detect the time to replace an absorbing member main body. DETAILED DESCRIPTION OF THE INVENTION

[0010] 1. Overview of sensors, detection systems, and detection methods

[0011] (1) A sensor according to an embodiment is a sensor for detecting the presence of a liquid, and comprises a first electrode and a second electrode, the first electrode and the second electrode having a thread-like or strip-like structure and arranged side by side in a direction intersecting the longitudinal direction, and at least one of the first electrode and the second electrode has a first portion having a first surface area at a first position in the longitudinal direction, and a second portion having a second surface area larger than the first surface area at a second position in the longitudinal direction different from the first position.

[0012] By making the second surface area of ​​the second portion larger than the first surface area of ​​the first portion, the area of ​​the second portion that comes into contact with the liquid is larger than that of the first portion. Therefore, when the same amount of liquid exists in the first portion and the second portion between the electrodes, the area of ​​the liquid between the electrodes in the second portion is larger than that between the electrodes in the first portion. Detection sensitivity In other words, the sensitivity can be made to vary depending on the position in the longitudinal direction of the sensor.

[0013] (2) Preferably, when a liquid is present between the first and second electrodes made of different materials, a generated electric power is generated between the electrodes, and a second generated electric power generated by the second portion is greater than a first generated electric power generated by the first portion. Since the second generated electric power is greater than the first generated electric power, the sensitivity of the sensor that detects the presence of a liquid using the generated electric power can be varied in the longitudinal direction.

[0014] (3) Preferably, the sensor further includes an output unit that outputs a detection signal indicating the detection of liquid, the output unit being connected to the first electrode and the second electrode, thereby enabling the sensor to output the detection signal according to the generated power.

[0015] (4) Preferably, the first electrode and the second electrode are provided in contact with an absorbent body of a wearing article having an absorbent body for receiving body exudates, and the first position is located forward of the second position when the wearing article is worn by a wearer. The wearing article having an absorbent body for receiving body exudates is, for example, a diaper.

[0016] By providing the first electrode and the second electrode in contact with the absorbent body of a wearing article having an absorbent body that receives excrement, the sensor can detect the presence or absence of excrement in the wearing article by the liquid contained in the excrement. By providing the first electrode and the second electrode so that the first position is located forward of the second position when the wearing article is worn by a wearer, the sensitivity at the rear can be made higher than the sensitivity at the front. When excrement occurs at the front of the wearing article and the wearer is in a supine position, the liquid absorbed in the absorbent body travels rearward, and the entire absorbent body becomes fully absorbed. By providing the sensitivity at the rear higher than the sensitivity at the front, the sensor can detect the state in which the entire absorbent body has absorbed the liquid, i.e., in the case of a diaper, the timing of changing the absorbent body can be detected.

[0017] (5) Preferably, at least one of the first electrode and the second electrode is sewn to the fabric, which makes it easy to make the surface areas of the first and second portions different.

[0018] (6) Preferably, the first and second portions have different stitching structures for the electrodes on the fabric. The stitching structure refers to the structure formed by the electrodes being sewn to the fabric. When the electrodes have a thread-like or strip-like structure, different stitching structures can easily make the surface areas of the first and second portions different.

[0019] (7) Preferably, the stitching structure of the second portion has a higher density of electrodes per unit of fabric than the stitching structure of the first portion, thereby making the second surface area that can come into contact with liquid larger than the first surface area.

[0020] (8) Preferably, the first electrode and the second electrode are in contact with each other via a water absorbent body, and at least one of the first electrode and the second electrode is sewn to the water absorbent body as a substrate, and the stitching structure of the second portion has a shorter stitching pitch than the stitching structure of the first portion, thereby making it possible to make the second surface area that can come into contact with liquid larger than the first surface area.

[0021] (9) Preferably, the stitching structure of the second portion has a larger area of ​​electrodes that appear on the surface of the fabric that comes into contact with liquid than the stitching structure of the first portion. This allows the second surface area that can come into contact with liquid when the surface of the fabric is in contact with the absorbent body to be larger than the first surface area.

[0022] (10) Preferably, the stitching structure of the second portion has an overlap in the stitching direction of the electrodes, which allows the second surface area that can come into contact with liquid to be larger than the first surface area.

[0023] (11) A detection system according to an embodiment is a system for detecting the presence of a liquid in a detectable body, and includes a sensor mounted on the detectable body and having a first electrode and a second electrode, a communicator connected to the sensor and outputting the sensing results of the sensor via wireless communication, and a receiver for receiving the sensing results, wherein the first electrode and the second electrode have a thread-like or strip-like structure and are arranged side by side in a direction intersecting the longitudinal direction, and at least one of the first electrode and the second electrode has a first portion having a first surface area at a first longitudinal position, and a second portion having a second surface area larger than the first surface area at a second longitudinal position different from the first position.

[0024] By making the second surface area of ​​the second portion larger than the first surface area of ​​the first portion, it is possible to vary the sensitivity depending on the position in the longitudinal direction of the sensor. By mounting this sensor on a detection object, it is possible to detect the presence of liquid depending on the position when the detection object has a position where the presence of liquid is primarily detected and a position where the presence of liquid is preliminarily detected, such as a diaper. By having a communication device that outputs the sensing result of the sensor via wireless communication and a receiver that receives the sensing result, the sensing result can be obtained from the signal received by the receiver. Therefore, it is possible to obtain the sensing result remotely or without touching the detection object.

[0025] (12) A detection method according to an embodiment is a method for detecting the presence of a liquid, comprising: arranging a first electrode and a second electrode having a thread-like or strip-like structure in parallel in a direction intersecting the longitudinal direction; the first electrode and the second electrode are made of different materials; when a liquid is present between the electrodes, power is generated between the electrodes; at least one of the first electrode and the second electrode has a first portion having a first surface area at a first longitudinal position, and a second portion having a second surface area larger than the first surface area at a second longitudinal position different from the first position; and detecting that the amount of generated power exceeds a threshold value, thereby detecting the presence of a predetermined amount of liquid; the threshold value is greater than the maximum amount of power generated by the first portion and less than the maximum amount of power generated by the second portion.

[0026] By using a sensor in which the second surface area of ​​the second portion is larger than the first surface area of ​​the first portion, it is possible to detect the presence of liquid with different sensitivities in the longitudinal direction of the sensor. By mounting this sensor on the object to be detected, if the object to be detected has a position where the presence of liquid is primarily detected and a position where the presence of liquid is preliminarily detected, such as a diaper, it is possible to detect the presence of liquid in the second portion by comparing the amount of power generated by the second portion with a threshold value.

[0027] 2. Examples of sensors, detection systems, and detection methods

[0028] FIG. 1 is a schematic diagram of a detection system 100 according to this embodiment. The detection system 100 is a system that detects the presence of liquid in a detection object. In this embodiment, the detection object is an absorbent member main body 5. The detection system 100 detects liquid present in the absorbent member main body 5 by a sensor 1 installed in the absorbent member main body 5. FIG. 2 is a cross-sectional view of the absorbent member main body 5 taken along line MM in FIG. 1.

[0029] In this embodiment, the absorbent member main body 5 has the basic structure of a diaper. That is, the absorbent member main body 5 comprises a topsheet 51, a backsheet 52, and an absorbent body 53. The absorbent body 53 is disposed between the topsheet 51 and the backsheet 52. When worn by a wearer, the absorbent member main body 5 has a front side 54 located in front of the wearer and a rear side 55 located behind the wearer. The wearer's excrement is passed from the topsheet 51 side to the absorbent body 53. The absorbent member main body 5 is substantially rectangular in plan view in the unfolded state.

[0030] The top sheet 51 is a liquid-permeable sheet having a substantially rectangular shape. The top sheet 51 is formed of, for example, a nonwoven fabric or a woven fabric. The top sheet 51 comes into contact with the wearer's skin when worn by the wearer. The top sheet 51 is configured to improve liquid permeability and to prevent permeated liquid from flowing back toward the wearer. This allows urine excreted by the wearer to quickly permeate into the absorbent body 53. Therefore, even if urination occurs, the top sheet 51 does not substantially retain urine and remains substantially dry as long as the absorbent body 53 has a remaining water absorption capacity. As a result, urine is prevented from coming into contact with the wearer's skin.

[0031] The back sheet 52 is a liquid-impermeable sheet having a substantially rectangular shape. The back sheet 52 is made of a waterproof material such as a waterproof film. The back sheet 52 prevents urine absorbed by the absorber 53 from leaking to the outside.

[0032] The absorbent body 53 is composed of absorbent fibers such as pulp and a superabsorbent polymer. The superabsorbent polymer allows the absorbent body 53 to hold a large amount of liquid. The absorbent body 53 is a substantially rectangular mat body that is long from front to back. The longitudinal direction of the absorbent body 53 roughly coincides with the front to back direction of the absorbent member main body 5, and the absorbent body 53 is disposed across the front side 54 and rear side 55 of the absorbent member main body 5. Therefore, the absorbent body 53 absorbs urine excreted on the front side 54, and can also absorb urine in excess of the absorption capacity of the front side 54 on the rear side 55.

[0033] The sensor 1 is disposed between the absorbent body 53 and the backsheet 52. That is, the sensor 1 is disposed on the backsheet 52 side of the absorbent body 53. The sensor 1 functions as a urine-generating battery. The sensor 1 has a pair of electrodes 11, 12. The electrodes 11, 12 each have a thread-like or strip-like structure. The sensor 1 is disposed so that the pair of electrodes 11, 12 are spaced apart in the width direction, which intersects with the longitudinal direction, and are in contact with the absorbent body 53. The pair of electrodes 11, 12 are disposed so as to extend in the front-rear direction along the absorbent body 53, which is long in the front-rear direction. That is, the electrodes 11, 12 are disposed so that their longitudinal directions roughly coincide with the longitudinal direction of the absorbent body 53.

[0034] Electrodes 11 and 12 function as a positive electrode and a negative electrode, respectively. Electrodes 11 and 12 generate electricity when in contact with a liquid present between the electrodes. Sensor 1 detects the presence of a liquid between electrodes 11 and 12 based on the power generated by electrodes 11 and 12.

[0035] At least one of the electrodes 11, 12 is sewn to the fabric 13. In this example, both the electrodes 11, 12 have conductive thread-like structures and are sewn to the fabric 13. The electrode 11, which functions as the positive electrode, is made of silver thread, for example. The electrode 12, which functions as the negative electrode, is made of aluminum thread, for example. The fabric 13 is a fabric, for example, made of cotton fabric. The fabric 13 is arranged in contact with the back sheet 52 side of the absorbent body 53. As a result, the electrodes 11, 12, which are made of thread sewn to the fabric 13, are in contact with the back sheet 52 side of the absorbent body 53.

[0036] The electrode 11, which is at least one of the electrodes 11 and 12, has a first portion 111 having a first surface area S1 at a position (first position in the longitudinal direction) corresponding to the front side 54 of the absorbent member main body 5, and a second portion 112 having a second surface area S2 at a position (second position in the longitudinal direction) corresponding to the rear side 55 of the absorbent member main body 5. The second surface area S2 is larger than the first surface area S1 (S2>S1). The surface area refers to the area in contact with the absorbent body 53, and refers to the surface area of ​​the portion of the electrodes 11 and 12, which are formed by thread sewn into the fabric 13, exposed on at least the surface of the fabric 13 facing the absorbent body 53.

[0037] The first portion 111 and the second portion 112 of the electrode 11 have different stitching structures for the thread on the fabric 13. The stitching structure refers to the structure that the thread forms on the fabric 13 when the thread is sewn to the fabric. One example of the difference in the stitching structures for the first portion 111 and the second portion 112 is that the stitching methods for the thread forming the electrode 11 are different between the first portion 111 and the second portion 112. Specifically, the second portion 112 is sewn in a way that results in a higher density per unit of fabric 13 than the first portion 111.

[0038] An example of a stitching method with a high density per unit of fabric 13 is a stitching method in which the thread forming the electrode 11 appears over a large area on the surface of fabric 13 facing the absorber 53. For example, the first portion 111 is sewn to fabric 13 with a wave stitch, and the second portion 112 is sewn to fabric 13 with a backstitch. The backstitch refers to a full backstitch or a half backstitch.

[0039] As another example, as shown in Figure 1, the second portion 112 is sewn with a longer stitch length than the first portion 111. In the example of Figure 1, the first portion 111 is sewn with a single wave stitch, while the second portion 112 is sewn with a stitch that has overlapping stitches in the sewing direction of the thread.

[0040] The fabric 13 is made of fabric and may function as a part of the absorbent body 53. In this case, the electrodes 11, 12 sewn to the fabric 13 are arranged with the water absorber sandwiched therebetween. In this case, one example of a stitching method that provides a high density per unit of fabric 13 is a stitching method in which the thread forming the electrode 11 is sewn to the fabric 13 at a short pitch. Specifically, the first portion 111 is sewn to the fabric 13 with a long-pitch wavy stitch, and the second portion 112 is sewn to the fabric 13 with a short-pitch wavy stitch.

[0041] As a result, the threads forming the electrode 11 are more exposed to the surface of the fabric 13 facing the absorber 53 in the second portion 112 than in the first portion 111. Therefore, the electrode 11 comes into contact with the absorber 53 more in the second portion 112 than in the first portion 111.

[0042] In the above example, both electrodes 11 and 12 have a conductive thread-like structure, but either one of electrodes 11 and 12 may have a conductive strip-like structure.

[0043] Since the electrodes 11 and 12 are disposed in contact with the absorber 53, the absorber 53 that has absorbed the liquid becomes a path for generating a current between the electrodes 11 and 12. Therefore, a current is generated in the electrodes 11 and 12 when they come into contact with the liquid absorbed by the absorber 53. Since the electrodes 11 and 12 generate electricity using the liquid absorbed by the absorber 53, the sensor 1 is used to detect the absorption of liquid into the absorber 53.

[0044] The sensor 1 is connected to the detection device 3. The detection device 3 is connected to the ends of the electrodes 11 and 12 on the front side 54. This prevents the detection device 3 from pressing against the body when a wearer wearing the absorbent member main body 5 lies supine.

[0045] 3 is a schematic diagram showing the configuration of the detection device 3. Referring to FIG. 3, the detection device 3 includes a capacitor 31. The capacitor 31 is connected to the sensor 1 and stores the power generated by the electrodes 11 and 12.

[0046] The detection device 3 includes an intermittent power supply conversion circuit 32. A capacitor 31 is connected to a power supply terminal of the intermittent power supply conversion circuit 32. The intermittent power supply conversion circuit 32 operates using the capacitor 31 as its operating power source. The intermittent power supply conversion circuit 32 monitors the charging voltage of the capacitor 31.

[0047] A wireless transmitter 33 is connected to the intermittent power supply conversion circuit 32. The wireless transmitter 33 performs wireless communication with the receiver 7. The wireless communication is, for example, Bluetooth (registered trademark) or Bluetooth Low Energy (registered trademark).

[0048] When the intermittent power supply conversion circuit 32 detects that the charging voltage of the capacitor 31 has reached a set voltage Vt that is set as a driving condition of the wireless transmitter 33, the intermittent power supply conversion circuit 32 supplies the power charged in the capacitor 31 to the wireless transmitter 33. As a result, a wireless signal SG is output from the wireless transmitter 33.

[0049] When the intermittent power supply conversion circuit 32 consumes the power of the capacitor 31 by supplying it to the wireless transmitter 33, the potential of the capacitor 31 drops and the intermittent power supply conversion circuit 32 stops operating, thereby stopping the supply of power to the wireless transmitter 33. If the electrodes 11 and 12 are generating power, the capacitor 31 will be charged again.

[0050] When the electrodes 11 and 12 are generating electricity, the capacitor 31 repeatedly charges and discharges. Accordingly, the output of the wireless signal SG from the wireless transmitter 33 becomes intermittent. Therefore, the wireless signal SG output from the wireless transmitter 33 becomes a detection signal indicating the detection of liquid present between the electrodes 11 and 12.

[0051] The interval H between the outputs of the wireless signal SG from the wireless transmitter 33 depends on the charging speed of the capacitor 31. The charging speed increases as the amount of power generated increases. Therefore, the interval H between the outputs of the wireless signal SG from the wireless transmitter 33 decreases as the amount of power generated by the electrodes 11 and 12 increases, and increases as the amount of power generated decreases.

[0052] The more electrodes 11 and 12 are in contact with the liquid, the greater the amount of power generated. That is, since electrodes 11 and 12 are arranged in contact with absorber 53 with their longitudinal directions roughly aligned with the longitudinal direction of absorber 53, the greater the amount of power generated becomes as the amount of liquid absorbed by absorber 53 increases. Therefore, the interval H between outputs of wireless signals SG from wireless transmitter 33 represents the amount of liquid absorbed by absorber 53.

[0053] The wireless signal SG transmitted from the transmitter 95 is received by the receiver 7. The receiver 7 is connected to a management device 9 and provides the received wireless signal SG to the management device 9. The management device 9 is a computer having a processor 91 and a memory 92, and is, for example, a terminal device such as a smartphone.

[0054] The processor 91 executes a program stored in the memory 92 to perform processing related to the absorbency of the absorber 53 of the absorbent member main body 5. Processing related to the absorbency of the absorber 53 of the absorbent member main body 5 is, for example, processing to determine whether or not a diaper change is necessary. The absorbent member main body 5 determines that it is time to change the diaper when liquid reaches the rear side 55 of the absorber 53. If it is determined that a diaper change is necessary, the output device 93 of the management device 9 outputs a message indicating that a diaper change is necessary.

[0055] The inventors placed a sensor 1 having an electrode 11 made of silver thread and an electrode 12 made of aluminum thread in an absorbent member main body 5, and measured the generated current of the sensor 1 while injecting liquid into the absorbent member main body 5, obtaining the generated current characteristics shown in Figure 4. In the measurement, liquid was injected from the front side 54 of the absorbent member main body 5, and the generated current of the sensor 1 was measured over time. In Figure 4, the elapsed time is represented by the length of the absorber 53 that has absorbed the liquid in the longitudinal direction from the end of the front side 54, i.e., the length of the electrode that is in contact with the liquid (wet length). The horizontal axis of Figure 4 represents the wet length, and the vertical axis represents the magnitude of the generated current.

[0056] Measurement result L11 in Figure 4 shows the measurement result of the generated current of sensor 1 in which electrode 12 is formed by wavy stitching aluminum thread on cotton fabric 13, and electrode 11 is formed by wavy stitching in the first portion 111 and by backstitching five times in the second portion 112, overlapping in the sewing direction. Measurement result L21 in Figure 4 is a measurement result as a comparative example, showing the measurement result of the generated current under the same conditions as sensor 1, for a sensor in which electrode 11 is formed by wavy stitching silver thread without overlapping in the sewing direction. The longitudinal length of electrodes 11 and 12 of sensor 1 used was 520 mm, and the first portion 111 of electrode 11 was 440 mm and the second portion 112 was 80 mm.

[0057] Value A represents the measurement result L11 when the wet length is approximately 310 mm. Position P1, which is approximately 310 mm from the end of the front side 54 of the absorbent member main body 5, is a point included in the first portion 111. Therefore, value A is a measurement value when liquid has been absorbed into the absorber 53 up to position P1, but no liquid has been absorbed into the second portion 112.

[0058] Value B represents the measurement value of measurement result L11 when the wet length is approximately 450 mm. Value C represents the measurement value of measurement result L21 when the wet length is approximately 440 mm. Position P2, approximately 440 mm from the end of the front side 54 of the absorbent member main body 5, and position P3, approximately 450 mm from the end, are points included in the second portion 112. Therefore, values ​​B and C are both measured when the liquid has been absorbed up to the second portion 112.

[0059] 4, it was confirmed that the generated current for both measurement results L11 and L21 tends to increase as the wetted length of the electrode increases. When the wetted length becomes longer than 440 mm, which is the first portion 111, the rate of increase in the measured value for measurement result L11 becomes much more rapid than the rate of increase in the measured value for measurement result L21, and the generated current characteristic was such that value B was 150 μA or more greater than value C.

[0060] 4, it was verified that by making the second surface area S2 of the second portion 112 of the electrode 11 larger than the first surface area S1 of the first portion 111, the amount of power generated when the liquid reaches the second portion 112 can be made much larger than the amount of power generated when the liquid is absorbed up to the first portion 111, compared to when the surface area is not changed. In other words, it was verified that the amount of power generated by the sensor 1 before and after the liquid reaches the second portion 112 of the absorber 53 can be made to differ greatly.

[0061] In the sensor 1, the amount of electricity generated when the liquid reaches the second portion 112 is significantly greater than the amount of electricity generated when the liquid is absorbed up to the first portion 111, thereby making it possible to increase the difference in charging speed to the capacitor 31 between when the liquid is absorbed up to the first portion 111 and when the liquid reaches the second portion 112.

[0062] When detecting water supply to the second portion 112, it is also possible to provide the electrode 11 or 12 only on the second portion 112, i.e., only on the rear side 55. However, by providing the electrode 11 up to the first portion 111, the sensor 1 generates electricity over the entire longitudinal direction, thereby increasing the amount of power generated.

[0063] The inventors connected a detection device 3 to the sensor 1 used in the measurement of Figure 4 and the sensor according to the comparative example, and measured the change over time in the charging voltage of the capacitor 31 to obtain the charging characteristics shown in Figure 5. To charge the capacitor 31, the power generated by the sensor 1 and the sensor according to the comparative example when the liquid had been absorbed into the absorber 53 up to points P2 and P3, where values ​​B and C of Figure 4 were obtained, was used. An aluminum electrolytic capacitor with a load capacity of 4.4 mF was used as the capacitor 31. The horizontal axis of Figure 5 represents the elapsed time from the start of charging, and the vertical axis represents the charging voltage.

[0064] 5 shows the measurement result of the charging voltage when sensor 1 was used, and measurement result L22 shows the measurement result of the charging voltage when a sensor according to the comparative example was used. In both measurement results L12 and L22, the charging voltage rose sharply at time T1, about 10 seconds after the start of charging, and then rose more gradually.

[0065] In Figure 5, measurement result L12 shows that the charging voltage exceeds 0.6 V at time T1, whereas measurement result L22 shows that the charging voltage at time T1 only rises to about 0.5 V. In measurement result L22, there is a gradual rise after time T1, and it takes 150 seconds from the start of charging for the charging voltage to reach 0.6 V.

[0066] This result shows that by making the second surface area S2 of the second portion 112 larger than the first surface area S1 of the first portion 111, the capacitor 31 can be charged more quickly than when not making it larger. In other words, it was verified that the charging speed of the capacitor 31 can be made to differ greatly before and after the liquid reaches the second portion 112 of the absorber 53.

[0067] Based on these verifications, the set voltage Vt of the intermittent power supply conversion circuit 32 of the detection device 3 is set to be lower than the charging voltage of the capacitor 31 when the sensor 1 is used at time T1, and higher than the charging voltage when the sensor according to the comparative example is used. In other words, the set voltage Vt is set to be higher than the maximum amount of power generated in the first portion 111 and lower than the maximum amount of power generated in the second portion 112. In the case of the sensor 1 used in the verifications of FIGS. 4 and 5, the set voltage Vt is set to be 0.6 V or higher (Vt≦0.6 V), as an example. Preferably, the set voltage Vt is set to be 0.6 V (Vt=0.6 V).

[0068] As a result, when the absorber 53 has absorbed liquid up to a position corresponding to the first portion 111 but has not yet reached a position corresponding to the second portion 112, the wireless transmitter 33 is not activated. As a result, in this state, the wireless signal SG is not output. When the liquid reaches the second portion 112, the wireless transmitter 33 is activated. As a result, the wireless signal SG is output. Therefore, by receiving the wireless signal SG with the receiver 7, that is, by varying the surface area in the longitudinal direction in this manner, the liquid detection accuracy in the longitudinal direction of the sensor 1 can be varied. The management device 9 can determine whether the absorber 53 has sufficiently absorbed liquid, i.e., whether the diaper is effective.

[0069] The inventors constructed a detection system 100 by mounting the sensor 1 used in the measurements of Figures 4 and 5 on an absorbent member main body 5 (diaper), and conducted an experiment to detect the time to replace the absorbent member main body 5 using the detection system 100. The absorbent member main body 5 used was designed so that water was poured from the front side 54, and the water absorption of the absorber 53 progressed from the front side 54 to the rear side 55. The absorber 53 was brought to a state where it had absorbed water up to the rear side 55 by pouring a total of about 600 ml of water. Physiological saline was used as the liquid.

[0070] In the experiment, the amount of liquid injected per injection was set to 600 ml, with the second injection being injected 600 seconds or more after the first injection, for a total of 600 ml of liquid injected into the absorbent member body 5. Whether or not the receiver 7 received the wireless signal SG from the start of injection was measured, and the measurement results shown in Figure 6 were obtained. The horizontal axis of Figure 6 represents the elapsed time from the start of injection, and the vertical axis represents whether or not the wireless signal SG was received. A value of "0" indicates no reception, and a value of "1" indicates reception.

[0071] From the results in Figure 6, during the period T2 after the first injection and before the second injection, the wireless signal SG was received once after 71 seconds. During the period T3 after the second injection, the first signal was received 22 seconds after the injection, and four more signals were received thereafter. During the period T3, the wireless signal SG was received five times over a 600-second period.

[0072] From this result, it can be seen that the amount of power generated by the sensor 1 increases more rapidly during period T3 than during period T2. In other words, it can be seen that in the first injection, the first portion 111 comes into contact with the liquid, but the second portion 112 does not, whereas in the second injection, the second portion 112 comes into contact with the liquid. Therefore, it has been verified that by using the detection system 100, the management device 9 can determine that it is time to change the diaper when the reception interval H of the wireless signal SG is smaller than the threshold value and the wireless signal SG has been received a predetermined number of times or more.

[0073] In the management device 9, the threshold for the reception interval H of the wireless signal SG is set to a value shorter than the reception interval when the first portion 111 generates the maximum amount of power and longer than the reception interval when the second portion 112 generates the maximum amount of power. This makes it possible to set the threshold for the amount of power generated to a value greater than the maximum amount of power generated by the first portion 111 and less than the maximum amount of power generated by the second portion 112, and detecting that this threshold has been exceeded when the reception interval becomes shorter than the threshold. In other words, the detection system 100 can reliably detect that liquid has come into contact with the second portion 112, and can reliably determine when the diaper needs to be changed.

[0074] <3. Notes> The present invention is not limited to the above-described embodiment, and various modifications are possible. [Explanation of symbols]

[0075] 1: Sensor 3:Detection device 5: Absorbing member body 7: Receiver 9: Management device 11: Electrode 12: Electrode 13: Fabric 31: Capacitor 32: Intermittent power supply conversion circuit 33: Radio transmitter 51: Surface sheet 52: Back sheet 53: Absorbent 54: Front 55: Rear side 91: Processor 92: Memory 93: Output device 95: Transmitter 100: Detection system 111 :1st part 112:Second part H: Reception interval L11: Measurement results L12: Measurement result L21: Measurement results L22: Measurement result S1: 1st surface area S2 :Second surface area SG: Radio signal T2: Period T3: Period Vt: Set voltage

Claims

1. A sensor comprising a first electrode and a second electrode, which detects the presence of a liquid that generates power between the first electrode and the second electrode by the generated power, the first electrode and the second electrode have a thread-like or strip-like structure and are arranged side by side in a direction intersecting the longitudinal direction; At least one of the first electrode and the second electrode has a first portion having a first surface area at a first position in the longitudinal direction, and a second portion having a second surface area larger than the first surface area at a second position in the longitudinal direction different from the first position. Sensor.

2. the first electrode and the second electrode are made of different materials; A second generated power generated by the second portion is greater than a first generated power generated by the first portion. The sensor of claim 1 .

3. an output unit that outputs a detection signal indicating the detection of the liquid; The output section is connected to the first electrode and the second electrode. The sensor of claim 2 .

4. the first electrode and the second electrode are provided in contact with an absorbent body of a wearing article having an absorbent body that receives body exudates, The first position is located forward of the second position when the wearer puts on the wearing article. The sensor according to any one of claims 1 to 3.

5. At least one of the first electrode and the second electrode is sewn to a fabric. The sensor according to any one of claims 1 to 4.

6. The first portion and the second portion have different stitching structures for the electrodes and the fabric. The sensor of claim 5.

7. The stitching structure of the second portion has a higher density of electrodes per unit of the fabric than the stitching structure of the first portion. The sensor of claim 6.

8. the first electrode and the second electrode are in contact with each other via a water absorbent body; At least one of the first electrode and the second electrode is sewn to the water absorbent body as the fabric, The stitching pitch of the second portion is shorter than that of the first portion. The sensor of claim 7.

9. The stitching structure of the second portion has a larger area of ​​electrodes that appear on the surface of the fabric that comes into contact with the liquid than the stitching structure of the first portion. The sensor of claim 6.

10. The stitching structure of the second portion has an overlap with respect to the stitching direction of the electrode. The sensor of claim 9.

11. A system having a first electrode and a second electrode mounted on a detection object, the system detecting the presence of a liquid that generates generated power between the first electrode and the second electrode by the generated power, a sensor that detects the presence of the liquid based on the generated power generated between the first electrode and the second electrode; a communication device connected to the sensor and configured to output a sensing result of the sensor via wireless communication; a receiver that receives the sensing result, the first electrode and the second electrode have a thread-like or strip-like structure and are arranged side by side in a direction intersecting the longitudinal direction; At least one of the first electrode and the second electrode has a first portion having a first surface area at a first position in the longitudinal direction, and a second portion having a second surface area larger than the first surface area at a second position in the longitudinal direction different from the first position. Detection system.

12. A method for detecting the presence of a liquid that generates electric power between a first electrode and a second electrode by the generated electric power, comprising: The first electrode and the second electrode, each having a thread-like or strip-like structure, are arranged in parallel in a direction intersecting the longitudinal direction, the first electrode and the second electrode are made of different materials, and when the liquid is present between the electrodes, electric power is generated between the electrodes; At least one of the first electrode and the second electrode comprises a first portion having a first surface area at a first position in the longitudinal direction, and a second portion having a second surface area larger than the first surface area at a second position in the longitudinal direction different from the first position, detecting that the amount of generated power exceeds a threshold value, thereby detecting that a predetermined amount of liquid is present; The threshold value is a value that is greater than the maximum value of the amount of power generated by the first portion and less than the maximum value of the amount of power generated by the second portion. Detection method.

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