JP7517943B2 - Diaper and wetness detection system thereof - Google Patents

Description

The present invention relates to a diaper and a wetness detection system thereof, and in particular to a diaper and a wetness detection system thereof that can detect wetness without a battery.

Some diaper wearers, such as elderly people, are unable to inform their caregivers that their diapers need to be changed. Delaying a diaper change can lead to skin rashes, so caregivers need to change diapers appropriately.

In order to reduce the burden on caregivers, a diaper and detection system capable of detecting the wetness of the diaper have been proposed (Patent Document 1).

JP 2015-57088 A

Conventionally proposed methods for detecting the wetness of a diaper cannot distinguish between an unused diaper and a diaper that has been used but is not wet, so it is necessary to use a reader to check whether a diaper in use is wet. This requires the caregiver to stand close to the diaper wearer and point the reader at the diaper to check, which does not necessarily reduce the burden on the caregiver. The object of the present invention is to provide a diaper and a wetness detection system that can detect the wetness of a diaper from a location away from the diaper wearer.

In order to achieve the above-mentioned object, the invention of claim 1 of the present application is a diaper comprising a main body portion having a ventral portion, a crotch portion and a dorsal portion, a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body arranged between the top sheet and the back sheet, wherein a sensor element is arranged so that at least a portion of it is in contact with the absorbent body, and the sensor element comprises an antenna for transmitting and receiving signals, and a delay element for delaying the signal received by the antenna in accordance with the wetness state of the diaper and generating a signal to be returned from the antenna, and wherein the antenna functions as a loop antenna only when the diaper is being worn.

The invention according to claim 2 of the present application is characterized in that, in the diaper according to claim 1, a pair of connecting parts are provided on both sides of the dorsal part of the main body part, which respectively connect to the surface of the abdominal part, and the antenna comprises a first antenna part arranged on the abdominal part, a second antenna part arranged on the dorsal part, and a third antenna part arranged on the connecting parts, and when worn, a loop antenna can be formed by the first antenna part, the second antenna part, and the third antenna part.

The invention according to claim 3 of the present application is characterized in that in the diaper according to claim 1, the main body is pants-shaped with the ventral side and a part of the dorsal side being continuous, the antenna is made up of a fourth antenna part arranged continuously with the ventral side and the dorsal side, and when worn, the fourth antenna part can form a loop antenna.

The invention of claim 4 of the present application is a system for detecting wetness of a diaper from the detection result of a sensor element provided in the diaper, comprising a transmitter that transmits a question signal from a detection device side antenna, the sensor element that receives the question signal at a diaper side antenna, generates a response signal from the question signal and outputs it from the diaper side antenna, a receiver that receives the response signal at the detection device side antenna, and a determination device that determines the wetness of the diaper from the question signal and the response signal, wherein the sensor element comprises the diaper side antenna that functions as a loop antenna only when the diaper is being worn, and a delay element that delays the question signal received by the diaper side antenna in accordance with the wetness of the diaper, and generates the response signal to be returned from the diaper side antenna.

The invention according to claim 5 of the present application is characterized in that in the wetness detection system according to claim 4, when the response signal is received with a delay time shorter than a preset delay time, the determination device determines that the diaper is wet.

The invention according to claim 6 of the present application is characterized in that in the wetness detection system according to claim 4, when the response signal is no longer received after the response signal has been received with a delay time longer than a preset delay time, the determination device determines that the diaper is wet.

The invention according to claim 7 of the present application is characterized in that in the wetness detection system according to any one of claims 4 to 6, the diaper to be detected comprises a main body having a ventral portion, a crotch portion and a dorsal portion, a pair of connection portions on both sides of the dorsal portion of the main body that are connected to the surface of the ventral portion, a first antenna portion arranged on the ventral portion, a second antenna portion arranged on the dorsal portion and a third antenna portion arranged on the connection portions, and the first antenna portion, the second antenna portion and the third antenna portion of the diaper when worn form a loop antenna that serves as the diaper-side antenna.

The invention according to claim 8 of the present application is characterized in that in the wetness detection system according to any one of claims 4 to 6, the diaper to be detected is a pants-type diaper in which the ventral side and a part of the dorsal side are continuous, and the diaper has a fourth antenna part arranged continuously with the ventral side and the dorsal side, and the fourth antenna part of the diaper when worn forms a loop antenna that serves as the diaper-side antenna.

The diaper of the present invention is configured with an antenna that does not function when the diaper is folded and unused, but functions only when the diaper is being worn. The wetness detection system using the diaper of the present invention obtains a predetermined response signal only when the diaper is being worn and functions as a diaper-side antenna, making it possible to detect the wetness of the diaper at a location away from the diaper wearer without requiring a reader.

1 is an explanatory diagram of a tape-type diaper according to a first embodiment of the present invention. FIG. FIG. 2 is an explanatory diagram of a sensor element according to the first embodiment of the present invention. FIG. 1 is an explanatory diagram of a wetness detection system according to a first embodiment of the present invention. 4A to 4C are diagrams illustrating a detection method of the wetness detection system according to the first embodiment of the present invention. FIG. 13 is an explanatory diagram of a pants-type diaper according to a second embodiment of the present invention.

The diaper of the present invention is configured to include a sensor element in a typical diaper. This sensor element includes an antenna that functions only when the diaper is being worn, and a delay element that generates a response signal that is returned by delaying a query signal received by the antenna according to the wetness of the diaper.

An antenna that functions only when the diaper is worn is one that does not function as an antenna when the diaper is folded. For example, when the diaper is folded, no loop antenna is formed, or the spacing between the loop antennas is narrow and radiation is low, so it does not function as an antenna, but when the diaper is worn, a loop antenna is formed, and the spacing between the conductors that form the loop antenna becomes wider, so it functions as an antenna.

The delay element is an element that generates a response signal by delaying the interrogation signal received by the antenna by a predetermined time when the diaper is not wet, and is configured to shorten the delay time depending on the wetness state. The delay time when the diaper is wet can also be set to be so short that the interrogation signal and the response signal cannot be distinguished.

The wetness detection system using the diaper of the present invention is configured such that a question signal is sent from a transmitter, a sensor element that receives this question signal sends back a response signal according to the wetness state of the diaper, and a receiver receives the response signal, thereby determining wetness from the question signal and the response signal.

The wetness state is determined, for example, by determining that the diaper is wet when the response signal sent from the sensor element has a delay time shorter than a preset delay time. The diaper is also determined to be wet when the sensor element receives a response signal with a delay time longer than a preset delay time, and then no longer receives a response signal. Below, an embodiment of the diaper and wetness detection system of the present invention will be described in detail.

A first embodiment of the present invention will be described. The diaper of the present invention can be formed as a general disposable diaper. The diaper of this embodiment is a tape-type diaper as shown in FIG. 1. As shown in FIG. 1(a), the diaper body 10 is composed of a ventral portion 11, a crotch portion 12, a back portion 13, and connection portions 14 at both ends of the back portion 13. When such a diaper is worn by a care recipient, the connection portions 14 are connected to the surface of the ventral portion 11. FIG. 1(b) is a cross-sectional view of the A-A surface of the crotch portion 12 of the diaper body 10 shown in FIG. 1(a), and has a structure in which an absorbent 17 for absorbing urine, etc. is arranged between a liquid-permeable top sheet 15 that allows urine, etc. to pass through and a liquid-impermeable back sheet 16 that does not allow urine, etc. to pass through. In the example shown in FIG. 1(b), a delay element 22 that becomes a part of the sensor element 20 is arranged under the liquid-permeable top sheet 15 and on the absorbent 17. The delay element 22 can be formed by printing a desired shape on nonwoven fabric or the like with conductive ink, or by patterning metal foil. Although not shown, an intermediate sheet for preventing backflow may be placed on the delay element 22. The delay element 22 can also be placed under the absorbent body 17 and on the liquid-impermeable back sheet 16, as long as the delay element 22 is placed so that it comes into contact with urine or the like.

The first antenna section 21a, which constitutes part of the antenna, is formed on the back side of the abdominal section 11 of the diaper main body 10 (the surface that becomes the front when worn), the second antenna section 21b, which constitutes part of the antenna, is formed on the front or back side of the dorsal section 13, and the third antenna section 21c is formed on the front side of the connection section 14 (the surface that adheres to the front of the abdominal section 11 when worn). The first to third antenna sections 21a to 21c can be formed by printing on the diaper main body 10 with conductive ink or by patterning metal foil. Alternatively, the first to third antenna sections 21a to 21c can be formed by attaching tape-like shapes to the diaper main body 10.

As shown in FIG. 1(a), the delay element 22 and the second antenna section 21b are connected. As described below, when worn, the third antenna section 21c is connected to both ends of the first antenna section 21a, so that the first to third antenna sections 21a to 21c are connected to form a loop antenna, and this loop antenna is connected to the delay element 22.

The first to third antenna sections 21a to 21c function as antennas only when the diaper is being worn, and do not function as antennas when the diaper is folded before being worn or when it is unfolded as shown in FIG. 1(a). In other words, an unworn diaper does not transmit a response signal in the wetness detection system described below.

When functioning as an antenna while worn, the first to third antenna sections 21a to 21c can be formed in multiple layers to increase the antenna gain, and then connected together to form a configuration with multiple loop antennas.

In the example shown in FIG. 1(a), the delay element 22 connected to the second antenna portion 21b is configured with a meandering conductive wire. As shown in FIG. 2, the delay element 22 configured in this manner has an inductor connected in series to the end connected to the antenna 21 consisting of the first to third antenna portions 21a to 21c, and the end opposite the end connected to the antenna 21 is an open end. In addition, a capacitor is connected by an adjacent conductive wire to form a resonator.

Next, the wetness detection system will be described. The diaper of this embodiment is worn by a person receiving care, and the first to third antenna sections 21a to 21c form a continuous antenna. Figure 3 is an explanatory diagram of the wetness detection system 40 of this embodiment.

As shown in FIG. 3, a sensor element 20 is formed on the diaper side. This sensor element 20 is composed of a diaper-side antenna 21A (antenna 21) that functions as an antenna when worn as described above, and a delay element 22 connected to it. In this embodiment, the diaper-side antenna 21A constitutes a loop antenna, so it functions as an antenna only when worn and does not function as an antenna when folded or when the first to third antenna sections 21a to 21c are not connected. Therefore, even if an unused diaper is placed around the care recipient, it will not affect the wetness detection system 40 of the present invention.

The detection device 30, on the other hand, is equipped with a detection device-side antenna 31, a transmitter 32 and a receiver 33 connected to the detection device-side antenna 31, and a determination device 34 to which the interrogation signal transmitted from the transmitter 32 and the response signal received by the receiver 33 are input.

When detecting whether the diaper is wet, the transmitter 32 is controlled to output a burst signal. For example, a 315 MHz burst signal is output from the detector antenna 31 as an interrogation signal. This interrogation signal is received by the diaper antenna 21A. One end of the delay element 22 is connected to the diaper antenna 21A. The other end of the delay element 22 is open, so when the diaper is not wet or the wetness is not enough to affect the characteristics of the delay element 22, the interrogation signal received by the diaper antenna 21A propagates through the delay element 22, is totally reflected at the other end, propagates through the delay element 22 again, and is output as a response signal from the diaper antenna 21A. This response signal is received by the receiver 33. The determination device 34 compares the interrogation signal with the response signal to determine whether the diaper is wet.

As described above, when the diaper is folded or when the first to third antenna units 21a to 21c are not connected, it does not function as an antenna, so no response signal is output from the folded diaper or the like in response to the interrogation signal sent from the detection device 30.

Figure 4 shows the interrogation signal transmitted from the detection device side antenna 31, the response signal received by the detection device side antenna 31, and the signal strength of the interrogation signal and response signal detected in the determination device 34. The interrogation signal transmitted from the detection device side antenna 31 is received by the diaper side antenna 21A with almost no delay, so the interrogation signal received by the diaper side antenna is almost the same as the interrogation signal of the detection device side antenna. Also, the response signal transmitted from the diaper side antenna 21A is received by the detection device side antenna 31 with almost no delay, so the interrogation signal transmitted from the diaper side antenna 21A is almost the same as the response signal of the detection device side antenna.

The method of detecting wetness will be explained using Figures 3 and 4. Figure 4(a) shows a signal when the diaper is not wet, or when the diaper is wet but not wet enough to affect the delay element 21. As shown in Figure 4(a), a response signal having a sufficiently long delay time to a question signal transmitted from the detection device antenna 31 is received by the detection device antenna 31. The determination device 34 detects the delay time from the signal strength of the signal (question signal) input from the transmitter 32 and the signal (response signal) input from the receiver 33. If the delay time of the detected response signal is longer than a preset delay time, it is determined that there is no wetness (the diaper does not need to be changed).

Figure 4 (b) shows a wet diaper. When wetness reaches a part of the delay element 22 of the sensor element 20 of the diaper, causing a short circuit between adjacent conductive wires or disappearing conductive wires, the conductive wire of the delay element 22 becomes shorter. As a result, a response signal with a shorter delay time is obtained than when the diaper is not wet (state of Figure 4a). The determination device 34 detects the signal strength of the signal (question signal) input from the transmitter 32 and the signal (response signal) input from the receiver 33. If the delay time of this detected response signal is shorter than a preset delay time, it is determined that the diaper is wet (the diaper needs to be changed). The delay time for determining that the diaper is wet can be set appropriately depending on the arrangement and size of the delay element 22.

Figure 4(c) also shows a wet diaper. As in Figure 4(b), a response signal with a shorter delay time than the non-wet state is obtained, and a response signal with an even shorter delay time than the state shown in Figure 4(b) is obtained. In the determination device 34 in this state, when the signal strength of the signal (question signal) input from the transmitter 32 and the signal (response signal) input from the receiver 33 is detected, the question signal and the response signal overlap, and the response signal appears to have disappeared. When the diaper is not wet, signals are usually transmitted and received as shown in Figure 4(a), so when the state changes from the state in which signals are transmitted and received as shown in Figure 4(a) to the state in which signals are transmitted and received as shown in Figure 4(c), it can be determined that the diaper is wet (the diaper needs to be changed). In order to detect changes in the delay time over time, the detection device 30 may be configured to include a memory device.

Generally, such transmission and reception of question signals and response signals is a relatively short distance communication due to battery-less communication, so communication may be via a repeater.

If the determination device 34 determines that the diaper is wet, the caregiver or the like can be notified by a communication means (not shown) that the diaper needs to be changed. This communication can be either wired communication or wireless communication. The caregiver or the like who is notified that the diaper needs to be changed can learn that the diaper needs to be changed at a location away from the care recipient or the like. For example, a message requesting that the diaper be changed can be sent to the caregiver's mobile information terminal, or displayed on a display device that the caregiver or the like can recognize.

Next, a second embodiment will be described. In the above first embodiment, a tape-type diaper is used as a diaper-side antenna while being worn, but the present invention is not limited to tape-type diapers. It is possible for the present invention to detect wetness even when a commonly used pants-type diaper is used.

As shown in Fig. 5, the pants-type diaper main body 10 has a shape in which the abdominal side portion 11 and the dorsal side portion 13 are partly continuous, and a fourth antenna portion 21d is formed along the waist portion of the wearer when the diaper is worn. This fourth antenna portion 21d becomes the diaper-side antenna 21A when the diaper is worn. As in the first embodiment, the fourth antenna portion 21d is formed with a delay element 22 which becomes part of the sensor element 20. The configuration of the delay element 22 is the same. The only difference from the first embodiment is that the shape of the diaper main body 10 is different, and the loop antenna is formed with the fourth antenna portion 21d instead of the first to third antenna portions 21a to 21c.

Therefore, the fourth antenna section 21d functions as an antenna only when the diaper is being worn, and does not function as an antenna when the diaper is folded before being worn, which is the same as in the first embodiment described above. In other words, a pants-type diaper that is not being worn will not transmit a response signal in the wetness detection system.

When functioning as an antenna while worn, the fourth antenna section 21d can be formed in multiple parts to increase the antenna gain, and the parts can be connected together to form a configuration with multiple loop antennas.

The fourth antenna portion 21d formed on the pants-type diaper is formed continuously, so there is no need to connect the first to third antenna portions 21a to 21c formed on the tape-type diaper described in the first embodiment in a continuous manner, and the antenna can be formed easily.

Next, the wetness detection system will be described. The diaper of this embodiment is worn by a person receiving care, and the fourth antenna portion 21d functions as an antenna.

In this embodiment, as shown in FIG. 3, a sensor element 20 is formed on the diaper side. This sensor element 20 is composed of a diaper-side antenna 21A that functions as an antenna when worn and a delay element 22 connected to it. The diaper-side antenna 21 consisting of the fourth antenna section 21d forms a loop antenna, so it functions as an antenna only when worn and does not function as an antenna when folded. Therefore, even if an unused diaper is placed around the care recipient, it will not affect the wetness detection system 40 of the present invention.

The detection device 30, on the other hand, is equipped with a detection device-side antenna 31, a transmitter 32 and a receiver 33 connected to the detection device-side antenna, and a determination device 34 to which the interrogation signal transmitted from the transmitter 32 and the response signal received by the receiver 33 are input.

When detecting whether the diaper is wet, the transmitter 32 is controlled to output a burst signal. For example, a 315 MHz burst signal is output from the detector antenna 31 as an interrogation signal. This interrogation signal is received by the diaper antenna 21A. One end of the delay element 22 is connected to the diaper antenna 21A. The other end of the delay element 22 is open, so when the diaper is not wet or the wetness is not enough to affect the characteristics of the delay element 22, the interrogation signal received by the diaper antenna 21A propagates through the delay element 22, is totally reflected at the other end, propagates through the delay element 22 again, and is output as a response signal from the diaper antenna 21A. This response signal is received by the receiver 33. The determination device 34 compares the interrogation signal with the response signal to determine whether the diaper is wet.

As mentioned above, the diaper does not function as an antenna when folded, so no response signal is output from the folded diaper in response to the interrogation signal sent from the detection device 30.

Figure 4 shows the interrogation signal transmitted from the detection device side antenna 31, the response signal received by the detection device side antenna 31, and the signal strength of the interrogation signal and response signal detected in the determination device 34. The interrogation signal transmitted from the detection device side antenna 31 is received by the diaper side antenna 21A with almost no delay, so the interrogation signal received by the diaper side antenna is almost the same as the interrogation signal of the detection device side antenna. Also, the response signal transmitted from the diaper side antenna 21A is received by the detection device side antenna 31 with almost no delay, so the interrogation signal transmitted from the diaper side antenna 21A is almost the same as the response signal of the detection device side antenna.

The method of detecting wetness will be explained using Figures 3 and 4. Figure 4(a) shows a signal when the diaper is not wet, or when the diaper is wet but not wet enough to affect the delay element 22. As shown in Figure 4(a), a response signal having a sufficiently long delay time to a question signal transmitted from the detection device antenna 31 is received by the detection device antenna 31. The determination device 34 detects the delay time from the signal strength of the signal (question signal) input from the transmitter 32 and the signal (response signal) input from the receiver 33. If the delay time of this detected response signal is longer than a preset delay time, it is determined that there is no wetness (the diaper does not need to be changed).

Figure 4 (b) shows a wet diaper. When wetness reaches a part of the delay element 22 of the sensor element 20 of the diaper, causing a short circuit between adjacent conductive wires or disappearing conductive wires, the conductive wire of the delay element 22 becomes shorter. As a result, a response signal with a shorter delay time is obtained than when the diaper is not wet (state of Figure 4a). The determination device 34 detects the signal strength of the signal (question signal) input from the transmitter 32 and the signal (response signal) input from the receiver 33. If the delay time of this detected response signal is shorter than a preset delay time, it is determined that the diaper is wet (the diaper needs to be changed). The delay time for determining that the diaper is wet can be set appropriately depending on the arrangement and size of the delay element 22.

Figure 4(c) also shows a wet diaper. As in Figure 4(b), a response signal with a shorter delay time than the non-wet state is obtained, and a response signal with an even shorter delay time than the state shown in Figure 4(b) is obtained. In the determination device 34 in this state, when the signal strength of the signal (question signal) input from the transmitter 32 and the signal (response signal) input from the receiver 33 is detected, the question signal and the response signal overlap, and the response signal appears to have disappeared. When the diaper is not wet, signals are usually transmitted and received as shown in Figure 4(a), so when the state changes from the state in which signals are transmitted and received as shown in Figure 4(a) to the state in which signals are transmitted and received as shown in Figure 4(c), it can be determined that the diaper is wet (the diaper needs to be changed). In order to detect changes in the delay time over time, the detection device 30 may be configured to include a memory device.

Generally, such transmission and reception of question signals and response signals is a relatively short distance communication due to battery-less communication, so communication may be via a repeater.

If the determination device 34 determines that the diaper is wet, the caregiver or the like can be notified by a communication means (not shown) that the diaper needs to be changed. This communication can be either wired communication or wireless communication. The caregiver or the like who is notified that the diaper needs to be changed can learn that the diaper needs to be changed at a location away from the care recipient or the like. For example, a message requesting that the diaper be changed can be sent to the caregiver's mobile information terminal, or displayed on a display device that the caregiver or the like can recognize.

Although the embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to the above embodiments. For example, in the above embodiments, the antenna on the detector side was described as a transmitting and receiving antenna, but it can be configured to be separated into a transmitting antenna and a receiving antenna.

10: diaper main body, 11: abdominal side portion, 12: crotch portion, 13: back side portion, 14: connection portion, 15: liquid-permeable top sheet, 16: liquid-impermeable back sheet, 17: absorbent body,
20: sensor element, 21: antenna, 21A: diaper side antenna, 21a: first antenna portion, 21b: second antenna portion, 21c: third antenna portion, 21d: fourth antenna portion,
30: detection device, 31: detection device side antenna, 32: transmitter, 33: receiver, 34: determination device,
40: Wetness detection system

Claims (8)

A diaper comprising a main body portion having a ventral portion, a crotch portion and a back portion, a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body disposed between the top sheet and the back sheet,
A sensor element is disposed so that at least a portion of the sensor element is in contact with the absorbent body,
The sensor element includes an antenna for transmitting and receiving a signal, and a delay element for delaying the signal received by the antenna in accordance with the wetness state of the diaper to generate a signal to be returned from the antenna,
The diaper is characterized in that the antenna functions as a loop antenna only when the diaper is worn. The diaper according to claim 1,
A pair of connection parts is provided on both sides of the dorsal side part of the main body part, the connection parts being connected to the surface of the ventral side part,
the antenna comprises a first antenna portion disposed on the ventral portion, a second antenna portion disposed on the dorsal portion, and a third antenna portion disposed on the connection portion;
A diaper, characterized in that, when worn, a loop antenna can be formed by the first antenna portion, the second antenna portion and the third antenna portion. The diaper according to claim 1,
The main body portion is a pants-type body in which the ventral portion and a part of the dorsal portion are continuous with each other,
The antenna comprises a fourth antenna portion disposed continuously between the ventral portion and the dorsal portion,
A diaper, characterized in that, when worn, the fourth antenna portion can form a loop antenna. A system for detecting wetness of a diaper based on a detection result of a sensor element provided in the diaper, comprising:
a transmitter for transmitting an interrogation signal from an antenna on the detection device side;
the sensor element receiving the interrogation signal by a diaper-side antenna, generating a response signal from the interrogation signal, and outputting the response signal from the diaper-side antenna;
a receiver that receives the response signal via an antenna on the detection device side;
a determination device for determining whether the diaper is wet based on the question signal and the response signal,
A wetness detection system characterized in that the sensor element comprises a diaper-side antenna that functions as a loop antenna only when the diaper is being worn, and a delay element that delays the query signal received by the diaper-side antenna in accordance with the wetness state of the diaper and generates the response signal to be returned from the diaper-side antenna. 5. The wetness detection system according to claim 4,
A wetness detection system, characterized in that, when the response signal has a delay time shorter than a preset delay time, the determination device determines that the diaper is wet. 5. The wetness detection system according to claim 4,
A wetness detection system characterized in that the determination device determines that the diaper is wet when the response signal is no longer received after receiving the response signal with a delay time longer than a preset delay time. 7. The wetness detection system according to claim 4,
The diaper to be detected comprises a main body having a ventral portion, a crotch portion and a back portion, a pair of connecting portions on both sides of the back portion of the main body, the connecting portions being connected to a surface of the ventral portion, a first antenna portion disposed on the ventral portion, a second antenna portion disposed on the back portion and a third antenna portion disposed on the connecting portions,
A wetness detection system characterized in that the first antenna portion, the second antenna portion and the third antenna portion of the diaper when worn form a loop antenna which serves as the diaper side antenna. 7. The wetness detection system according to claim 4,
The diaper to be detected is a pants-type diaper in which a portion of a ventral side portion and a portion of a dorsal side portion are continuous,
a fourth antenna portion disposed continuously on the ventral portion and the dorsal portion;
A wetness detection system, characterized in that the fourth antenna portion of the diaper when worn forms a loop antenna serving as the diaper side antenna.

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