JP6278156B2 - Moisture detection method, RFIC reader, and moisture detection system - Google Patents

Description

  The present invention relates to a moisture detection method, an RFIC reader, and a moisture detection system that detect the presence of moisture using an RFIC device.

  Conventionally, in order to detect the presence of moisture, it has been necessary to use expensive components such as a semiconductor sensor for humidity detection.

  On the other hand, a wireless IC device that more easily detects the presence or absence of moisture has been proposed (see, for example, Patent Document 1). In the wireless IC device, an insulating material is interposed between the power supply circuit board and the antenna, and when the humidity increases, the electromagnetic coupling between the power supply circuit board and the antenna changes to detect that the communicable distance changes. Humidity is detected.

Japanese Patent No. 5182431

  However, examples of the insulating material include an epoxy resin in which cellulose is dispersed and an epoxy resin in which polyvinyl alcohol is dispersed. However, these materials have a small volume change with respect to the amount of moisture, and the use area of the insulating material is limited. It has been. For this reason, in the said wireless IC device, the detection power with respect to the presence or absence of moisture may not be sensitive.

  An object of the present invention is to provide a moisture detection method that can detect the presence of moisture in a simple and highly accurate manner.

  The moisture detection method according to the present invention uses an RFIC device attached to an object and whose communication distance changes in the presence of moisture and an RFIC reader, and a distance between the RFIC device and the RFIC reader using a spacer member. The presence or absence of moisture around the RFIC device is detected based on the success or failure of the communication.

An RFIC reader according to the present invention includes a communication unit that communicates with an RFIC device;
A spacer member for regulating the distance between the RFIC device and the communication unit;
Is provided.

Further, the moisture detection system according to the present invention is a moisture detection system that detects the presence or absence of moisture around the RFIC device using an RFIC device attached to an object and an RFIC reader.
The RFIC device is:
An RFIC element;
An antenna element connected to the RFIC element and having an opposing portion capable of capacitive coupling;
A water absorbing material provided in the vicinity of the facing portion of the antenna element;
With
The RFIC device changes the communication distance in the presence of moisture,
The RFIC reader is
A communication unit for communicating with the RFIC device;
A spacer member for regulating the distance between the RFIC device and the communication unit;
A determination unit configured to communicate while regulating the distance between the RFIC device and the communication unit with the spacer member, and determining the presence or absence of moisture based on the success or failure of the communication;
Is provided.

  According to the moisture detection method of the present invention, communication is performed while the distance between the RFIC device and the communication unit is regulated by the spacer member, and the presence or absence of moisture is determined based on the success or failure of the communication. Can detect presence.

  According to the RFIC reader according to the present invention, the distance between the RFIC device and the communication unit of the RFIC reader can be stably regulated by the spacer member.

  According to the moisture detection system of the present invention, communication is performed while the distance between the RFIC device and the communication unit is regulated by the spacer member, and the presence or absence of moisture is determined based on the success or failure of the communication. Can detect presence.

(A) is the schematic which shows the example of a use which stuck the RFIC device for moisture detection in the moisture detection system which concerns on Embodiment 1 to the diaper, (b) is a diaper in the moisture detection system of (a). It is the schematic which shows the restriction | limiting state of the space | interval of the RFIC device for moisture detection stuck on and RFIC reader. (A) is a top view which shows the structure of the RFIC device for moisture detection in the moisture detection system which concerns on Embodiment 1, (b) shows the cross-sectional structure seen from the direction of the AA line of (a). It is a schematic sectional drawing, (c) is an equivalent circuit schematic of the RFIC device for moisture detection which concerns on Embodiment 1. FIG. (A) is a schematic sectional drawing which shows the cross-section of an RFIC element, (b) is an equivalent circuit schematic of (a). FIG. 2 is a schematic diagram showing capacitive coupling when moisture is contained in a meander-shaped opposed portion of the antenna element of the moisture detection RFIC device in FIG. It is a flowchart of the water | moisture content detection method in the example of use with which the RFIC device for a water | moisture content detection was mounted | worn with the diaper. (A) is a side view of the RFIC device for moisture detection in the moisture detection system according to the second embodiment, (b) is a plan view of the RFIC device of (a), and (c) is (a) 2 is a bottom view of the RFIC device of FIG. It is a side view which shows the electric field distribution in the antenna elements 11 and 12 at the time of hold | maintaining water | moisture content in the water absorption material 4 of the RFIC device 10a for moisture detection in the moisture detection system which concerns on Embodiment 2. FIG. (A) is a schematic perspective view which shows the structure of the RFIC reader in the moisture detection system in Embodiment 3, (b) is a schematic perspective view which shows the structure of the RFIC reader of another example.

  The moisture detection method according to the first aspect includes an RFIC device that is attached to an object and whose communication distance changes in the presence of moisture, an RFIC reader, and a distance between the RFIC device and the RFIC reader that is a spacer member. , And the presence or absence of moisture around the RFIC device is detected based on the success or failure of the communication.

  According to the above configuration, moisture can be detected easily and with high accuracy.

  In the moisture detection method according to the second aspect, in the first aspect, as the RFIC device, an RFIC device whose communication distance is shortened in the presence of moisture is used, and the RFIC device and the RFIC reader cannot communicate with each other. When the state is reached, it may be determined that moisture exists around the RFIC device.

  According to the above configuration, the distance between the RFIC device and the RFIC reader can be set as an intermediate distance between the communication distances before and after the change of the communication distance of the RFIC device 10 that changes in the presence of moisture. Thus, the presence of moisture can be detected by the success or failure of communication.

  In the moisture detection method according to the third aspect, in the first or second aspect, the RFIC reader and the RFIC device may communicate with each other at a constant center frequency.

  According to the above configuration, it is easy to detect a communication disabled state when the center frequency of the RFIC device changes by communicating the RFIC reader and the RFIC device at a constant center frequency. When the center frequency of the RFIC device does not change, it is not necessary to change the reading frequency of the RFIC reader.

An RFIC reader according to a fourth aspect includes a communication unit that performs communication with an RFIC device;
A spacer member for regulating the distance between the RFIC device and the communication unit;
Is provided.

  According to the above configuration, the distance between the RFIC device and the communication unit of the RFIC reader can be stably regulated by the spacer member.

  The RFIC reader according to a fifth aspect is the above fourth aspect, wherein the distance between the RFIC device and the communication unit is communicated while being regulated by the spacer member, and the presence or absence of moisture is determined based on the success or failure of the communication. You may further provide the judgment part which judges.

  The presence of moisture can be detected by detecting the communication failure by the determination unit.

  In the RFIC reader according to the sixth aspect, in the fourth or fifth aspect, the spacer member may include a contact member that comes into contact with a target body provided with the RFIC device.

  Since the spacer member has the contact member, it is possible to reliably maintain a certain distance from the RFIC device by bringing the contact member into contact with the object provided with the RFIC device.

  In the RFIC reader according to a seventh aspect, in any one of the fourth to sixth aspects, the spacer member may be made of an insulating material.

  According to the said structure, the influence which it has on the communication with an RFIC device and an RFIC reader can be suppressed by comprising a spacer member with an insulating material.

The moisture detection system according to an eighth aspect is a moisture detection system that detects the presence or absence of moisture around the RFIC device using an RFIC device attached to a target object and an RFIC reader.
The RFIC device is:
An RFIC element;
An antenna element connected to the RFIC element and having an opposing portion capable of capacitive coupling;
A water absorbing material provided in the vicinity of the facing portion of the antenna element;
With
The RFIC device changes the communication distance in the presence of moisture,
The RFIC reader is
A communication unit for communicating with the RFIC device;
A spacer member for regulating the distance between the RFIC device and the communication unit;
A determination unit configured to communicate while regulating the distance between the RFIC device and the communication unit with the spacer member, and determining the presence or absence of moisture based on the success or failure of the communication;
Is provided.

  According to the above configuration, the distance between the RFIC device and the RFIC reader is communicated while being regulated by the spacer member, and the presence or absence of moisture around the RFIC device is determined based on the success or failure of the communication. The presence of can be detected.

  Hereinafter, a moisture detection system and a moisture detection method according to embodiments will be described with reference to the accompanying drawings. In the drawings, substantially the same members are denoted by the same reference numerals.

(Embodiment 1)
FIG. 1A is a schematic diagram illustrating an application example in which the moisture detection RFIC device 10 in the moisture detection system 50 according to Embodiment 1 is attached to a diaper 30. FIG. 1B is a schematic diagram showing a regulated state of the interval between the moisture detection RFIC device 10 attached to the diaper 30 and the RFIC reader 40 in the moisture detection system 50 of FIG.
The moisture detection system 50 according to the first embodiment is, for example, an RFIC system using a UHF band, and is attached to the diaper (target object) 30 and the RFIC device 10 whose communication distance changes in the presence of moisture, An RFIC reader 40 is used. Communication is performed while the distance between the RFIC device 10 and the RFIC reader 40 is regulated by the spacer member 44. Based on the success or failure of the communication, the presence or absence of moisture around the RFIC device 10 is detected. Specifically, as the RFIC device 10, when an RFIC device whose communication distance is shortened in the presence of moisture is used and the RFIC device 10 and the RFIC reader are in a communication disabled state, moisture is present around the RFIC device 10. It can be determined that it exists. The spacer member physically regulates the distance between the RFIC device and the RFIC reader, more specifically, the shortest distance between the antenna of the RFIC device and the antenna of the RFIC reader. For this reason, it is possible to avoid an erroneous determination that “there is no moisture” even though moisture is present even if the RFIC reader is too close to the RFIC device to communicate. In this moisture detection system, for example, the distance between the RFIC device 10 and the RFIC reader 40 can be set by the spacer member 44 as an intermediate distance between the communication distances before and after the change of the communication distance of the RFIC device 10 that changes in the presence of moisture. . Thereby, the presence of moisture can be detected easily and with high accuracy.

  Below, each member which comprises this moisture detection system 50 is demonstrated.

<RFIC device>
FIG. 2A is a plan view showing a configuration of the moisture detection RFIC device 10 in the moisture detection system 50 according to the first embodiment, and FIG. 2B is a line AA in FIG. FIG. 2 (c) is an equivalent circuit diagram of the moisture detection RFIC device according to the first embodiment.
The moisture detection RFIC device 10 in the moisture detection system 50 according to the first embodiment includes the RFIC element 1, the first antenna element 11 and the second antenna element 12 that are connected to the RFIC element 1 and extend in opposite directions. And the water absorbing material 2 that supports the first antenna element 11 and the second antenna element 12. Each of the first antenna element 11 and the second antenna element 12 has a meander shape and includes a plurality of facing portions 13 that can be capacitively coupled. The facing portion 13 includes a pair of element pieces facing each other in the antenna element and a gap therebetween. The water absorbing material 2 is a base sheet 2 that supports the RFIC element and the first antenna element 11 and the second antenna element 12. Further, as shown in the equivalent circuit diagram of FIG. 1C, the RFIC element 1, the first and second antenna elements 11 and 12, and the capacitor 9 are included. The capacitor 9 may be, for example, a C pattern in the RFIC element 1 or a stray capacitance.

FIG. 3A is a schematic cross-sectional view showing a cross-sectional structure of the RFIC element 1, and FIG. 3B is an equivalent circuit diagram of FIG.
The RFIC element 1 includes an RFIC chip 21 and a multilayer substrate 25 connected to the RFIC chip 21 via a conductive bonding material 22 and a terminal electrode 23. The RFIC chip 21 is sealed with a sealing resin 24. Further, the multilayer substrate 25, power supply circuit consisting of C pattern of L pattern and C1, C2, and _{C IC} such as L1 and L2 are built. C _IC is a stray capacitance of the RFIC chip 21. A resonance circuit is formed by the power feeding circuit, and the resonance frequency corresponds to the carrier frequency. And this electric power feeding circuit is comprised in the predetermined board | substrate. By providing the feeding circuit in this manner, the center frequency on the RFIC device side can be prevented from changing greatly even if the electrical length of the antenna element changes due to changes in the surrounding environment.
In other words, if the electrical length of the antenna element in the initial state is adjusted to a predetermined value (for example, the maximum gain state (2 / λ)), the communicable distance can be increased even when the antenna element is arranged in the vicinity of the human body. Although reduced, the RFIC device can be read at a certain distance. When the amount of moisture around the antenna element increases and the electrical length of the antenna element changes, the communicable distance further decreases. For example, for one RFIC device, the communicable distance in the initial state is 1 to 2 m, the communicable distance is 20 cm in a state where the surrounding environment is dry in a state where it is arranged in the vicinity of the human body, and the wet state Then, the communicable distance was 3 cm or less. Therefore, the RFIC at a certain distance, for example, an interval of 5 cm, between the communicable distance that has decreased in the presence of moisture (example: 3 cm or less) and the communicable distance in the absence of moisture (example: 20 cm). The device communicates with the RFIC reader. The presence or absence of moisture can be detected by detecting a communication impossible state by communication at a certain distance (example: 5 cm). Of course, since the RFIC device can be read even in the initial state (the state before being placed in the vicinity of the human body), its characteristic measurement and selection work can be performed with high accuracy, inventory management using the RFIC device, Logistics management is also possible. Note that the above example is a communicable distance at, for example, 0.25 W output, and the communicable distance naturally changes when the output or the like changes.

The RFIC element 1 and the first and second antenna elements 11 and 12 are connected by, for example, direct connection by the terminal electrode 26 in FIGS. 3A and 3B, but are not limited thereto. For example, the RFIC element 1 and the first and second antenna elements 11 and 12 may be coupled not only by direct connection but also by any combination such as capacitive coupling and magnetic field coupling.
3A and 3B, the RFIC element 1 is provided with the multilayer substrate 25 having a built-in power supply circuit. However, the present invention is not limited to this, and the power supply circuit may not be provided. When the feeder circuit is not provided, when moisture is held in the facing portion 13 provided on the surfaces of the first and second antenna elements 11 and 12, the electrical length of the antenna changes and the carrier frequency changes. As a result, when communication is performed at the same carrier frequency as in the dry state, the wireless communication state changes more greatly in the moisture retention state, and wireless communication itself becomes impossible. Therefore, moisture can be detected more.

The first antenna element 11 and the second antenna element 12 are meander-shaped antenna elements extending in opposite directions with the RFIC element 1 as a center. The first antenna element 11 and the second antenna element 12 each have a meander shape extending meandering in one direction. Each antenna element 11, 12 has a portion parallel to the extending direction and a portion perpendicular to the extending direction. The part parallel to the extending direction has one rectangular shape, the vertical part also has one rectangular shape, and the part parallel to the extending direction and the part perpendicular to the extending direction are connected at a right angle. Yes. The rectangular shape of the portion parallel to the extending direction and the rectangular shape of the portion perpendicular to the extending direction have the same constant width. Further, the rectangular shape of the portion perpendicular to the extending direction is arranged at a constant pitch along the extending direction.
Note that the number of antenna elements is not limited to two as described above, and may be one or two or more. Moreover, the extending direction is not limited to the opposite direction, and for example, the extending directions may be perpendicular to each other. Moreover, the 1st antenna element 11 and the 2nd antenna element 12 can be used as the some opposing part 13 which can carry out the capacity | capacitance coupling of several meander-shaped folding | turning parts. In addition, the opposing part 13 which can be capacitively coupled may be, for example, serial capacitive coupling or parallel capacitive coupling. Further, each element of the antenna element may be capacitively coupled in series. Alternatively, a plurality of pieces may be capacitively coupled in parallel to the pieces of the antenna element. The opposing portion that is capacitively coupled may be either a serial capacitively coupled opposing portion or a parallel capacitively coupled opposing portion. Thereby, the flexibility of the configuration of the antenna element can be increased.
The first antenna element 11 and the second antenna element 12 can be made of a material such as a copper foil, a copper plate, a copper plating film, a gold foil, a gold plate, or a gold plating film used for a normal antenna element. The material is not limited to the above example, and any material that is normally used can be used.

  As the water absorbing material 2, for example, a polymer water absorbing material (polymer water absorbing material) or the like can be used. An inorganic water-absorbing material can also be used. In inorganic water-absorbing materials, since the volume change is small, porous type water-absorbing materials represented by clay-based materials are particularly preferable. The water absorbing material 2 only needs to be able to support, that is, place, the RFIC element 1 and the first antenna element 11 and the second antenna element 12. Thereby, the water absorbing material 2 can also serve as a base material sheet, and the thickness of the entire RFIC device can be reduced. Further, the water absorbing material 2 itself does not need to have rigidity or the like, but when it has rigidity, the mechanical shock resistance can be improved. On the other hand, if the water absorbing material 2 has flexibility, the RFIC device 10 can be attached to a curved surface.

FIG. 4 is a schematic diagram showing the capacitive coupling 14 when moisture is contained in the meander-shaped facing portions 13 of the first and second antenna elements 11 and 12 of the moisture detection RFIC device 10 of FIG. is there. A capacitance is also formed between the open ends.
When the water absorbing material 2 absorbs moisture, the RFIC device 10 for detecting moisture according to Embodiment 1 shown in FIG. 4 is capacitively coupled 14 between the plurality of facing portions 13 of the first antenna element 11 and the second antenna element 12. As a result, stray capacitance increases and the electrical lengths of the first and second antenna elements 11 and 12 change. As a result, as shown in FIG. 4, the communication distance is shortened, the wireless communication state is changed, and further wireless communication itself is impossible. For example, when the base sheet 2 is made of a polymer water-absorbing material, the relative dielectric constant ε is about 5 when no water is absorbed. The relative dielectric constant ε when the substrate sheet 2 absorbs moisture is about 60. As a result, the stray capacitance at the plurality of facing portions 13 of the meander-shaped first and second antenna elements 11 and 12 increases, and the antenna length changes. For this reason, the communication distance is shortened, the wireless communication state is changed, and furthermore, wireless communication itself cannot be performed. The presence of moisture can be detected by detecting the change in the wireless communication state.

  Note that the moisture detection RFIC device 10 whose communication distance is shortened in the presence of moisture is limited to the case where the communication distance changes due to capacitive coupling to the first and second antenna elements 11 and 12 as described above. I can't. The “RFIC device that shortens the communication distance in the presence of moisture” includes, for example, a “moisture detection RFIC device with a humidity sensor” that is configured to control output according to humidity. .

  The moisture detection system 50 may further include a relay antenna that can relay the output of the moisture detection RFIC device 10 to extend the communicable range. The relay antenna may be coupled to at least one of the first or second antenna elements 11 and 12 of the moisture detection RFIC device 10.

The relay antenna is not limited to a linear shape, for example, and may be a curved shape. Further, the relay antenna may be wound around the diaper 30 or around the diaper 30. The relay antenna preferably has a thin shape such as a plate shape, a thin plate shape, a mesh shape, or a foil shape, but is not limited thereto. For example, it may be rod-shaped or linear.
Further, the relay antenna may be made of a conductive material that can emit radio waves. For example, materials such as copper foil, copper plate, copper plating film, gold foil, gold plate, gold plating film, aluminum foil, aluminum plate, aluminum film, silver foil, silver plate, and silver plating film can be used. The material is not limited to the above example, and any material that is normally used can be used. Moreover, formation of a thin film etc. is not restricted to plating, You may use printing, vapor deposition, etc. For example, a relay antenna made of conductive ink may be formed on the outer surface side of the diaper 30 by a printing method. Furthermore, you may comprise a relay antenna using an electroconductive fiber. For example, the relay antenna may be configured by depositing aluminum on a resin sheet or resin film such as polyethylene terephthalate (PET).

<RFIC reader>
The RFIC reader 40 includes a communication unit 42 that communicates with the RFIC device 10 and a spacer member 44 that regulates the distance between the RFIC device 10 and the communication unit 42. “Regulating the distance” means “keeping the distance between the RFIC device 10 and the communication unit 42 constant”. That is, it is possible to set the same distance even if the user changes.
Further, the distance between the RFIC device 10 and the communication unit 42 can be stably regulated by the spacer member 44. For example, even if the distance between the RFIC device 10 and the communication unit 42 is automatically measured and displayed, it is difficult for a person to see only the display and match the predetermined distance. On the other hand, by using the spacer member 44, the distance between the RFIC device 10 and the communication unit 42 can be easily and stably regulated. Further, the distance between the RFIC device 10 and the RFIC reader 40 is changed by the spacer member 44, for example, the communicable distance before and after the change of the communication distance of the RFIC device 10 that changes in the presence of moisture (example: 20 cm before change, after change) It can be set as an intermediate distance (example: 5 cm) of 3 cm or less. In FIG. 1A and FIG. 1B, the spacer member 44 has a rod shape and restricts only a single distance. However, the spacer member 44 is not limited to this, and the spacer member 44 and the RFIC device 10 are not limited to this. The distance from the RFIC reader 40 may be regulated in a plurality of stages. The spacer member 44 is preferably made of an insulating material because it hardly inhibits propagation of electromagnetic waves. Thereby, the influence on the communication between the RFIC device 10 and the RFIC reader 40 can be suppressed.
The RFIC reader 40 is preferably a handy type, but is not limited to a handy type, and may be a stationary type.

  Note that, as described above, when a relay antenna that can relay the output of the RFIC device 10 and extend the communicable range is provided, the relay antenna and the RFIC reader 40 are more distant than the distance between the RFIC device 10 and the RFIC reader 40. The distance from the RFIC reader 40 may be shortened. Therefore, when the distance between the relay antenna and the RFIC reader 40 is shorter than the distance between the RFIC device 10 and the RFIC reader 40, the distance from the relay antenna, not the distance from the RFIC device 10, by the spacer member 44. Should be read as restricting.

In addition, the RFIC reader 40 further includes a determination unit (not shown) that makes the communication between the RFIC device 10 and the RFIC reader 40 while regulating the distance with the spacer member 44 and determines the presence or absence of moisture based on the success or failure of the communication. You may prepare. For example, the determination unit may determine that the presence of moisture has been detected when it detects that communication is not possible. Furthermore, the spacer member 44 may have a contact member that contacts the diaper (target body) 30. Normally, the RFIC reader 40 is used without contact with the object. For this reason, it has been difficult to keep the distance between the RFIC reader and the object constant. When the spacer member 44 has a contact member as described above, a certain distance can be reliably maintained by bringing the contact member into contact with the object.
The RFIC reader 40 may change the center frequency between the dry state and the moisture retention state when communicating with the RFIC device 10. Or you may communicate with a fixed center frequency about a dry state and a moisture retention state. When the center frequency of the RFIC device 10 is not easily changed by the RFIC element 1, communication may be performed at a constant center frequency between the dry state and the moisture retention state. On the other hand, even when the center frequency of the RFIC device 10 changes greatly between the dry state and the moisture retention state, a large change can be detected by communicating at a constant center frequency between the dry state and the moisture retention state.
The determination of the “communication impossible” state may be made based on the success / failure of one communication as described later, or may be made based on the number of success / failures of a plurality of times of communication. Furthermore, regarding the count of success / failure of wireless communication, it may be determined that communication is impossible when the number of times of communication is not less than a predetermined threshold number, and the presence state of moisture by the RFIC device 10 may be detected.

FIG. 5 is a flowchart of a moisture detection method in an application example in which the moisture detection RFIC device 10 of FIG. 2 is attached to the diaper 30. In this moisture detection method, it is assumed that a care recipient is wearing the diaper 30 to which the moisture detection RFIC device 10 is attached.
(1) The moisture detection RFIC device 10 and the RFIC reader 40 are caused to communicate with each other while the interval between the moisture detection RFIC device 10 and the RFIC reader 40 is regulated (S01). The RFIC reader 40 may be a stationary type or a handy type. Further, for example, a spacer member 44 having a predetermined length may be provided below the communication unit 42 of the RFIC reader 40 to regulate the interval between the moisture detection RFIC device 10 and the RFIC reader 40.
(2) It is determined whether or not communication between the moisture detection RFIC device 10 and the RFIC reader 40 is possible (S02).
(3) If communication between the moisture detection RFIC device 10 and the RFIC reader 40 is impossible (NO), it is determined that moisture exists around the moisture detection RFIC device 10 (S03). In this case, moisture, that is, urine or stool is present in the diaper 30.
(4) On the other hand, if the moisture detection RFIC device 10 and the RFIC reader 40 can communicate with each other (YES), it is determined that there is no moisture around the moisture detection RFIC device 10 (S04). In this case, there is no moisture in the diaper 30 yet.
Note that the determination of the presence or absence of moisture due to the success or failure of communication may be made based on the success or failure of one communication, or may be determined based on the number of times of success or failure of communication. Furthermore, regarding the count of success / failure of wireless communication, it may be determined that communication is impossible when the number of times of communication is not less than a predetermined threshold number, and the presence state of moisture by the RFIC device 10 may be detected. Further, the moisture state in the diaper 30 may be displayed on the RFIC reader 40. Further, the display of the moisture state is not necessarily performed. For example, the presence of moisture may be notified by blinking a lamp or the like.
As described above, moisture can be detected by the moisture detection method using the moisture detection system 50 including the moisture detection RFIC device 10.

As described above, in the moisture detection system and the moisture detection method using the same according to Embodiment 1, the moisture detection RFIC device 10 is attached to the diaper 30. Specifically, the moisture detecting RFIC device 10 and the RFIC reader 40 are caused to communicate with each other while the interval between the moisture detecting RFIC device 10 and the RFIC reader 40 is regulated by the spacer member 44. If communication between the moisture detection RFIC device 10 and the RFIC reader 40 is impossible, moisture around the moisture detection RFIC device 10 can be detected. Therefore, it is possible to detect a urine or stool in the diaper 30 or a wet state due to sweat or the like. In addition, since the RFIC device is used, it is not necessary to use expensive parts such as a humidity detecting semiconductor sensor, and it can be configured at low cost. In addition, since the configuration itself is simple, the reliability is high. Note that the water absorption of the RFIC device 10 is preferably equal to or higher than the water absorption of the diaper 30. If the water absorption of the RFIC device 10 is lower than that of the diaper 30, the water detection performance is deteriorated.
In addition, although the case where the moisture detection RFIC device 10 is attached to the diaper 30 is given as an example of the use of the moisture detection system 50 and the moisture detection method in the above, it is not limited to the above application example. For example, the RFIC device 10 can be attached to the outside of a water pipe and used as a water leak detection RFIC device that detects water leak.

(Embodiment 2)
6A is a side view of the moisture detection RFIC device 10a in the moisture detection system according to the second embodiment, and FIG. 6B is a plan view of the RFIC device 10a of FIG. 6A. FIG. 6C is a bottom view of the RFIC device 10a of FIG. FIG. 7 is a side view showing the electric field distribution in antenna elements 11 and 12 when moisture is held in water-absorbing material 4 of moisture detection RFIC device 10a in the moisture detection system according to the second embodiment.
In contrast to the moisture detection RFIC device in the moisture detection system according to the first embodiment, the moisture detection RFIC device 10a is not a meander shape but a long rectangular shape or a rod. It differs in that it is a shape. Further, the water absorbing material 4 is not in direct contact with the first antenna element 11 and the second antenna element 12, and the first antenna element 11 and the second antenna element 12 via the hardly water absorbing material (or non-water absorbing material) 2a. It differs in that it is provided over the gap portion. In this moisture detection RFIC device 10a, when compared with the moisture detection RFIC device in the moisture detection system according to the first embodiment, the moisture detection RFIC device 10a further includes the first antenna element 11 and the second antenna element 12. The difference is that the facing portion 15 is capable of capacitive coupling. In addition, as shown in FIG. 7, by holding moisture in the water absorbing material 4 corresponding to the facing portion 15 of the gap portion between the first antenna element 11 and the second antenna element 12, the first antenna element 11 and the second antenna element 11 The electric field of the antenna element 12 can be concentrated on the gap portion 15. In this case, since the electric field other than the gap portion 15 between the first antenna element 11 and the second antenna element 12 becomes weak, the electrical length can be substantially increased. In FIG. 7, the electric force lines 16a of the gap portion 15 are displayed thickly to indicate that the electric field is strong, and the electric force lines 16b other than the gap portion 15 are indicated by dotted lines to indicate that the electric field is weak. As a result, the communication distance of the moisture detecting RFIC device 10a is shortened by retaining moisture in the water absorbing material 4 provided over the gap portion 15 between the first antenna element 11 and the second antenna element 12.

Note that when the moisture detection RFIC device 10a in the moisture detection system according to the second embodiment is compared with the wireless IC device described in Patent Document 1, the wireless IC device described in Patent Document 1 includes a power supply circuit board and an antenna. An insulating material is interposed between the two. For this reason, when the humidity of the environment changes, the electromagnetic coupling itself between the feeding circuit and the antenna may change.
In contrast, in the moisture detection RFIC device 10a in the moisture detection system according to the second embodiment, moisture is absorbed between the RFIC element 1 and the first and second antenna elements 11 and 12, and electromagnetic coupling is performed. The wireless IC device described in Patent Document 1 is different in that an insulating material to be changed is not interposed. When moisture is held in the water absorbing material 4, the electric field in the gap only changes and does not affect the electromagnetic coupling between the RFIC element 1 and the antennas 11, 12. Therefore, the moisture detecting RFIC device 10 a Can show stable performance. For this reason, it has high reliability.

The water absorbing material 4 may be provided over the gap portion (opposing portion) 15 between the first antenna element 11 and the second antenna element 12. Here, the water absorbing material 4 faces the gap portion (opposing portion) 15 between the first antenna element and the second antenna element via the hardly water absorbing material 2a. Also in this case, it can be said that the water absorbing material 4 is provided in the vicinity of the facing portion 15.
In addition, you may provide the water absorbing material 4 over the whole including the opposing part 15 of the 1st antenna element 11 and the 2nd antenna element 12. FIG. However, if the first antenna element 11 and the second antenna element 12 are provided over the entire portion including the facing portion 15, the electric field concentration effect on the facing portion 15 cannot be obtained, and the influence on the communication distance does not increase. Therefore, the water absorbing material 4 is preferably provided in 2/3 or less of the entire first antenna element 11 and second antenna element 12.
Moreover, the water absorbing material 4 can use paper or textiles which consist of a fiber which is hard to melt | dissolve in water, for example, gauze, tissue paper, etc. In addition, you may use the above-mentioned absorber. The water absorbing material 4 may be provided by sticking, fixing, spraying, printing, dipping or the like on the bottom surface side of the hardly water absorbing material 2a. The method of providing the water absorbing material 4 is not limited to the above example, and the water absorbing material 4 may be provided by a commonly used method. The water absorbing material 4 retains moisture therein, and the surface of the water absorbing material 4 may also contain moisture. It is preferable that the water absorbing material 4 can hold moisture for a long time.

(Embodiment 3)
FIG. 8A is a schematic perspective view showing a configuration of the RFIC reader 40a in the moisture detection system in the third embodiment, and FIG. 8B is a schematic perspective view showing a configuration of another example of the RFIC reader 40b. is there.
The RFIC reader 40 a includes a communication unit 42 that communicates with the moisture detection RFIC device, and a spacer member 44 a that regulates the distance between the moisture detection RFIC device and the communication unit 42. The spacer member 44a is different from the spacer member of the RFIC reader according to Embodiment 1 in that it is made of a cushion material having flexibility. Since the spacer member 44 a has flexibility, the spacer member 44 a is gentle to the care recipient even when the diaper having the RFIC device 10 attached thereto, and there is not much discomfort.
8B is different from the RFIC reader 40a shown in FIG. 8A in that the spacer member 44b is hollow and consists of only a skeleton. Thus, since the spacer member 44b is hollow and has only a framework, the influence of the spacer member 44b on the signal from the RFIC device can be suppressed.
The spacer member is not limited to that shown in FIGS. 8A and 8B, and any spacer member that can regulate the distance between the RFIC device and the communication unit of the RFIC reader may be used. For example, the impact at the time of hitting the surface in contact with the diaper as a net shape may be reduced, and the support portion may be a skeleton only.

  Note that the moisture detection RFIC device in the moisture detection system may be used in any band such as the LF band, the HF band, the UHF band, and the SHF band when used as an RFID tag. The RFIC device is typically an RFID tag, but is not limited to the one having a so-called tag function, and may have another function such as one having a reader / writer function.

  In addition, in this indication, it includes combining suitably any embodiment and / or Example of various embodiment and Example mentioned above, and each embodiment and / or Example is included. The effect which has can be show | played.

  In the moisture detection method according to the present invention, the RFIC device that is attached to the object and whose communication distance changes in the presence of moisture and the RFIC reader are regulated by the spacer member. Communication, and the presence or absence of moisture around the RFIC device is detected based on the success or failure of the communication. Therefore, moisture can be detected simply and with high accuracy, and it is useful for detecting moisture in diapers, detecting water leaks in piping, and the like.

1 RFIC element 2 Water-absorbing material (base sheet)
2a Hard to absorb water (base sheet)
3 Antenna pattern 4 Water-absorbing material 10, 10a RFIC device for moisture detection 11 First antenna element 12 Second antenna element 13 Opposing portion 14 Capacitive coupling 15 Opposing portions 16a, 16b Electric field lines 21 RFIC chip 22 Conductive bonding material 23 Terminal electrode 24 Sealing resin 25 Multilayer substrate 26a, 26b Terminal electrode 30 Diaper (object)
40, 40a, 40b Reader / writer 42 Communication unit 44, 44a, 44b Spacer member 50 Moisture detection system

Claims (17)

The RFIC device attached to the object and whose communication distance changes in the presence of moisture, and the RFIC reader, the distance between the RFIC device and the RFIC reader, and the communicable distance when the RFIC device is free of moisture And the distance between the communication distance reduced in the presence of moisture using a spacer member to regulate the communication, and based on the success or failure of the communication, around the RFIC device attached to the object A moisture detection method that detects the presence or absence of moisture.   When an RFIC device that shortens the communication distance in the presence of moisture is used as the RFIC device, and when the RFIC device and the RFIC reader are in a communication disabled state, it is determined that moisture exists around the RFIC device. The moisture detection method according to claim 1.   The moisture detection method according to claim 1 or 2, wherein the RFIC reader and the RFIC device communicate with each other at a constant center frequency. A communication unit that communicates with an RFIC device provided in a target body;
A spacer member that regulates a distance between the RFIC device and the communication unit to a distance between a communicable distance in a state where the RFIC device is free of moisture and a communicable distance reduced in the presence of moisture ;
RFIC reader equipped with.   5. The RFIC reader according to claim 4, further comprising a determination unit configured to perform communication while regulating a distance between the RFIC device and the communication unit with the spacer member, and to determine presence or absence of moisture based on success or failure of the communication. .   The RFIC reader according to claim 4, wherein the spacer member has a contact member that comes into contact with an object on which the RFIC device is provided.   The RFIC reader according to claim 4, wherein the spacer member is made of an insulating material. A moisture detection system that detects the presence or absence of moisture around the RFIC device using an RFIC device attached to an object and an RFIC reader,
The RFIC device is:
An RFIC element;
An antenna element connected to the RFIC element and having an opposing portion capable of capacitive coupling;
A water absorbing material provided in the vicinity of the facing portion of the antenna element;
With
The RFIC device changes the communication distance in the presence of moisture,
The RFIC reader is
A communication unit for communicating with the RFIC device;
A spacer member that regulates a distance between the RFIC device and the communication unit to a distance between a communicable distance in a state where the RFIC device is free of moisture and a communicable distance reduced in the presence of moisture ;
A determination unit configured to communicate while regulating the distance between the RFIC device and the communication unit with the spacer member, and determining the presence or absence of moisture based on the success or failure of the communication;
A moisture detection system.   The moisture detection method according to any one of claims 1 to 3, wherein the spacer member has flexibility.   The moisture detection method according to claim 1, wherein the object is a diaper.   The moisture detection method according to claim 10, wherein the diaper is provided with a relay antenna that relays the output of the RFIC device.   The RFIC reader according to claim 4, wherein the spacer member has flexibility.   The RFIC reader according to claim 4, wherein the object is a diaper.   The RFIC reader according to claim 13, wherein the diaper is provided with a relay antenna that relays the output of the RFIC device.   The moisture detection system according to claim 8, wherein the spacer member has flexibility.   The moisture detection system according to claim 8 or 15, wherein the object is a diaper.   The moisture detection system according to claim 16, wherein the diaper is provided with a relay antenna that relays the output of the RFIC device.

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