JP6668599B2 - RFIC device for moisture detection - Google Patents

Description

  The present invention relates to a moisture detection RFIC device for detecting moisture.

  Conventionally, it has been necessary to use expensive components such as a semiconductor sensor for temperature detection to detect moisture.

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

  Further, there is known a moisture detection sensor in which the periphery of a wireless IC tag is covered with a water-absorbing covering means (for example, see Patent Document 2).

Japanese Patent No. 5182431 JP 2006-29993 A

  In the wireless IC device described in Patent Document 1, as the insulating material, an epoxy resin in which cellulose is dispersed or an epoxy resin in which polyvinyl alcohol is dispersed is cited. It is small and the area of use of the insulating material is limited. Therefore, in the wireless IC device, the detection power for the presence or absence of moisture may not be sharp.

  In the moisture detection sensor described in Patent Literature 2, it is necessary to cover the periphery of the wireless IC tag with a water-absorbing substance while absorbing water. For this reason, there is a disadvantage that the product size is larger than a product having no moisture detection function. In addition, there is a problem in that a communication-disabled state is realized by the absorption of water by a water-absorbing substance, and a necessary function, that is, a communication-disabled state does not appear unless water is absorbed by the water-absorbing substance.

  An object of the present invention is to provide a device for detecting moisture that can detect the presence of moisture easily and with high accuracy.

An RFIC device for moisture detection according to the present invention includes an RFIC element,
A flat antenna element connected to the RFIC element;
With
The antenna element has holes or irregularities on its surface or side surface capable of retaining moisture.

  Since the RFIC device for detecting moisture according to the present invention has holes or irregularities capable of retaining moisture on the surface or side surface of the flat antenna element, the electrical length of the antenna element changes by retaining moisture in the holes or irregularities. Then, the wireless communication state changes. Therefore, the presence of moisture can be detected by detecting a change in the wireless communication state.

(A) is a schematic perspective view which shows the structure of the RFIC device for moisture detection which concerns on Embodiment 1, (b) is a side view of (a), (c) is a plane of (a). FIG. 2C is an equivalent circuit diagram of the moisture detecting RFIC device 10 according to the first embodiment. (A) is a schematic sectional view showing a sectional structure of an RFIC element, and (b) is an equivalent circuit diagram of (a). FIG. 2 is a schematic diagram showing an example of use in which the moisture detecting RFIC device according to Embodiment 1 is mounted on a diaper. 4 is a flowchart of diaper replacement in an application example in which the moisture detection RFIC device of FIG. 3 is mounted on a diaper. FIG. 9 is a schematic perspective view illustrating a configuration of a moisture detection RFIC device according to a second embodiment. FIG. 11 is a plan view showing a configuration of a moisture detection RFIC device according to a third embodiment. FIG. 14 is a schematic sectional view showing a sectional structure of a moisture detecting RFIC device according to a fourth embodiment. FIG. 14 is a schematic sectional view showing a sectional structure of a moisture detecting RFIC device according to a fifth embodiment. FIG. 15 is a schematic sectional view showing a sectional structure of a moisture detecting RFIC device according to a sixth embodiment. FIG. 15 is a schematic sectional view showing a sectional structure of a moisture detecting RFIC device according to a seventh embodiment. 15 is a flowchart of a diaper changing method by periodic patrol according to Embodiment 8.

The RFIC device for moisture detection according to the first aspect includes: an RFIC element;
A flat antenna element connected to the RFIC element;
With
The antenna element has holes or irregularities on its surface or side surface capable of retaining moisture.

  According to the above configuration, the surface or the side surface of the flat antenna element has holes or irregularities capable of retaining moisture. By retaining moisture in the holes or irregularities, the resonance frequency of the antenna element changes, and wireless communication is performed. The state changes. Therefore, the presence of moisture can be detected by detecting a change in the wireless communication state.

  In the moisture detection RFIC device according to a second aspect, in the first aspect, the antenna element may include a groove along a longitudinal direction of a surface.

  According to the above configuration, by holding moisture in the groove, the resonance frequency of the antenna element changes, and the wireless communication state changes. Therefore, the presence of moisture can be detected by detecting a change in the wireless communication state.

  In the RFIC device for moisture detection according to a third aspect, in the first aspect, the antenna element may include unevenness on a side surface.

  According to the above configuration, the resonance frequency of the antenna element changes by holding moisture in the unevenness on the side surface, and the wireless communication state changes. Therefore, the presence of moisture can be detected by detecting a change in the wireless communication state.

  The RFIC device for moisture detection according to a fourth aspect is the moisture detection RFIC device according to any one of the first to third aspects, wherein the antenna element is connected to the RFIC element and extends in different directions from each other. And a second antenna element.

  According to the above configuration, the RFIC device for detecting moisture can be configured by the dipole antenna.

  The RFIC device for moisture detection according to a fifth aspect is the RFIC device for moisture detection according to any one of the first to fourth aspects, further comprising a water-absorbing material provided to support the antenna element and to face the hole or the unevenness. May be provided.

  According to the above configuration, the water-absorbing material that guides the moisture to the holes or the irregularities can also serve as the base sheet, and the thickness of the entire moisture detecting RFIC device can be reduced.

The RFIC device for moisture detection according to a sixth aspect is the RFIC device for moisture detection according to any one of the first to fourth aspects, wherein:
While sandwiching the antenna element between the hardly water-absorbing material, and a water-absorbing material provided to face the hole or unevenness,
May be further provided.

  According to the above configuration, the hardly water-absorbing material can be used as the base sheet for supporting the antenna element, and the mechanical strength can be improved.

  The RFIC device for moisture detection according to a seventh aspect may further include, in the fifth aspect, upper and lower water absorbing materials sandwiching the antenna element, and two hard water absorbing materials sandwiching the antenna element from above and below.

  According to the above configuration, since the antenna element and the water absorbing material are sandwiched between the first water absorbing material and the second water absorbing material, moisture penetrates only along the longitudinal direction of the antenna element. I don't come. In this case, the amount of water absorption changes only gradually, and the antenna length also changes only gradually. Since the electrical length of the antenna element changes stepwise, the degree of water absorption can be detected stepwise.

  Hereinafter, an RFIC device for detecting moisture according to an embodiment 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 perspective view showing the configuration of the moisture detecting RFIC device 10 according to the first embodiment, and FIG. 1B is a side view of FIG. FIG. 1C is a plan view of FIG. 1A, and FIG. 1C is an equivalent circuit diagram of the moisture detecting RFIC device 10 according to the first embodiment.
The moisture detecting RFIC device 10 according to the first embodiment includes the RFIC element 1 and the first and second plate-like antenna elements 11 and 12 connected to the RFIC element and extending in opposite directions. In FIG. 1, two first and second antenna elements 11 and 12 are provided as antenna elements, but the present invention is not limited to this, and one antenna element may be used. Alternatively, two or more, for example, four antenna elements may be used. Each of the first and second antenna elements 11 and 12 has a plurality of holes 13 on its surface capable of retaining moisture. The mechanism for retaining moisture by the holes 13 is considered to be based on, for example, capillary action. The holes 13 may be through holes or semi-through holes. The holes 13 may be provided on the front surface and / or the back surface. The diameter of the hole 13 is, for example, 50 to 200 μm. The layout of the holes 13 may, for example, be uniform over the entire surface of the antenna element. Alternatively, it may be concentrated near the edge of the antenna element. Further, the holes 13 may be distributed line-symmetrically in each of the first and second antenna elements 11 and 12. Alternatively, the holes 13 may be distributed point-symmetrically in each of the first and second antenna elements 11 and 12. The hole 13 is preferably provided at an electric field concentration portion such as an end portion or a side end portion. The hole 13 itself is a portion where the electric field concentrates. In addition, the provision of the holes 13 can reduce the weight of the RFIC device 10 for detecting moisture.
As shown in the equivalent circuit diagram of FIG. 1C, the moisture detecting RFIC device 10 includes an RFIC element 1, first and second antenna elements 11 and 12, and a capacitor 6. The capacitor 6 may be, for example, a C pattern in the RFIC element 1 or a stray capacitance.

  The RFIC device 10 for moisture detection can perform wireless communication when moisture does not exist. However, in an environment where moisture exists, the RFIC device 10 is provided in the holes 13 provided on the surfaces of the first and second antenna elements 11 and 12. Holding the moisture changes the wireless communication state. Depending on the wireless communication state, wireless communication itself may not be possible. The case where the wireless communication state changes by retaining moisture in the holes 13 provided on the surfaces of the first and second antenna elements 11 and 12 is caused, for example, by a change in capacitance caused by retaining moisture in the holes. In this case, the communicable distance of the moisture detection RFIC device 10 changes. Further, depending on the wireless communication state, wireless communication itself may not be possible. Alternatively, the case where the wireless communication state changes means a case where the electrical length of the antenna changes and the carrier frequency changes. Also in this case, wireless communication itself may not be possible. Furthermore, the power of wireless communication may change and the wireless communication state may change. Also in this case, the wireless communication itself may not be possible due to the power reduction. In addition, the case where the wireless communication state changes may be due to various actions. The presence of moisture can be detected by detecting a change in the wireless communication state.

FIG. 2A is a schematic sectional view showing a sectional structure of the RFIC element 1, and FIG. 2B is an equivalent circuit diagram of FIG. 2A.
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 terminal electrodes 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 the stray capacitance of the RFIC chip 21. A resonance circuit is formed by the power supply circuit, and the resonance frequency corresponds to the carrier frequency. By providing the power supply circuit in this way, it is possible to prevent the center frequency of the carrier frequency from largely changing even when the electrical length of the antenna changes.
That is, if the electrical length of the antenna element in the initial state is adjusted to the maximum gain state (2 / λ), even if the water absorption increases and the electrical length of the antenna element changes, only the communicable distance is reduced. It is possible to read at the same carrier frequency. Therefore, the degree of water absorption can be detected by detecting the readable distance and counting the number of successful readings.

The RFIC element 1 and the first and second antenna elements 11 and 12 are connected by, for example, a direct connection by the terminal electrode 26 in FIGS. 2A and 2B, but are not limited thereto. For example, the RFIC element 1 and the first and second antenna elements 11 and 12 may be connected not only directly but also by any of coupling such as capacitive coupling and magnetic field coupling.
In FIGS. 2A and 2B, the RFIC element 1 is provided with the multilayer substrate 25 having the power supply circuit therein, but the present invention is not limited to this, and the power supply circuit may not be provided. By not providing the power supply circuit, the electrical length of the antenna is changed by retaining moisture in the holes 13 provided on the surfaces of the first and second antenna elements 11 and 12, so that the carrier frequency is changed and the wireless communication state is reduced. Can be changed. Further, wireless communication itself can be disabled. The presence of moisture can be detected by detecting a change in the wireless communication state.

The first antenna element 11 and the second antenna element 12 are flat plate-shaped antenna elements that extend in opposite directions about the RFIC element 1. The number of antenna elements is not limited to two as described above, but may be one or two or more. Further, the extending direction is not limited to the opposite direction, and may extend, for example, at right angles to each other. The surfaces of the first antenna element 11 and the second antenna element 12 are flat as shown in FIG. 1, but are not limited thereto, and may be curved. The arrangement of the holes 13 on the surface is not limited to the point-symmetric arrangement as shown in the plan view of FIG. 1C, and may be a line-symmetric arrangement. Alternatively, the arrangement may be asymmetric.
For the first antenna element 11 and the second antenna element 12, materials such as a copper foil, a copper plate, a copper plating film, a gold foil, a gold plate, and a gold plating film used for a normal antenna element can be used. The material is not limited to the above examples, and any commonly used material can be used.
The surface of the antenna element can be conceived in two ways, for example, a structure in which the surface is sealed with polyimide or the like, and a case in which a surface treatment such as rust prevention treatment is performed without sealing the surface. Further, the surface of the antenna element may be subjected to a hydrophilic treatment.

<Method of manufacturing RFIC device for detecting moisture>
The moisture detection RFIC device 10 is obtained by the following manufacturing method.
(1) A plurality of holes 13 are formed on the surface of the first and second flat antenna elements 11 and 12. For example, the plurality of holes 13 may be formed by etching the first and second antenna elements 11 and 12 made of copper foil. Alternatively, the plurality of holes 13 may be formed by laser processing the first and second antenna elements 11 and 12 made of copper foil. The area ratio between the hole 13 and the portion where the hole 13 is not provided may be, for example, 1: 1.
(2) The first and second antenna elements 11 and 12 provided with the plurality of holes 13 are connected to the RFIC element 1 to obtain the RFIC device 10 for detecting moisture. The connection between the first and second antenna elements 11 and 12 and the RFIC element 1 may be any of direct connection, capacitive coupling, magnetic field coupling, and the like.
Note that the surface of the antenna element may be subjected to a rust-preventive process to prevent oxidation.

FIG. 3 is a schematic diagram showing an application example in which the RFIC device for moisture detection 10 according to the first embodiment is mounted on a diaper 30.
As shown in FIG. 3, the moisture detecting RFIC device 10 according to the first embodiment is attached to a diaper 30. When moisture due to urine or the like is generated in the diaper 30, the first and second antennas are used. Moisture is retained in the holes, grooves, and irregularities on the surfaces of the elements 11 and 12, and the antenna length changes to shorten the communication distance, so that the wireless communication state changes. Furthermore, the wireless communication itself cannot be performed due to a change in the wireless communication state. The wireless communication with the RFIC device 10 is performed by the reader / writer 40 from the outside, and the communication distance with which the RFIC device 10 can be wirelessly communicated with the diaper 30 is detected. Can detect the presence state of water.

FIG. 4 is a flowchart of diaper replacement in an application example in which the moisture detecting RFIC device 10 of FIG.
(1) The caregiver needs to wear the diaper 30 to which the moisture detection RFIC device 10 has been mounted, and pairs the caregiver with the diaper 30 (S01).
(2) Next, first, the reader 40 of the moisture detecting RFIC device 10 is read (S02). The reader 40 may be a stationary type or a handy type. At this time, it is considered that there is no moisture in the diaper 30 at the time of wearing, and communication is possible.
(3) It is determined whether a predetermined time has elapsed since the previous reading (S03). If the predetermined time has not elapsed (NO), the process returns and the determination is repeated until the predetermined time has elapsed. The certain time is, for example, about 30 seconds. When a certain time has elapsed (YES), the process proceeds to the next step.
(3) Reading by the reader 40 of the moisture detecting RFIC device 10 (S04).
(4) It is determined whether or not communication with the moisture detection RFIC device 10 is possible (S05). If communication is possible (YES), it means that moisture does not yet exist in the diaper. The process returns to the time lapse determination (S03). On the other hand, if communication with the moisture detection RFIC device 10 is disabled (NO), moisture is present in the diaper 30, that is, urine or stool is present. Therefore, the process moves to the next step S06.
(5) Display the moisture condition in the diaper 30 on the reader 40 (S06). The caregiver may have a communication module other than the reader 40 and transmit information from the reader 40 to the communication module. Further, the display of the moisture state may not be necessarily performed. For example, the presence of moisture may be notified by blinking a lamp or the like.
(6) Thereafter, the caregiver removes the diaper 30, and the care-requirer wears a new diaper to which the moisture detecting RFIC device 10 has been mounted.
As described above, the diaper replacement in the application example in which the moisture detecting RFIC device 10 is mounted on the diaper 30 is performed. In the above flowchart, since the flow of one diaper change is schematically shown, the flow ends in step S06.

As described above, since the moisture detection RFIC device 10 according to the first embodiment is attached to the diaper 30 and moisture can be detected, it is possible to detect urine or stool or a wet state due to sweat or the like. In addition, since an RFIC device is used, it is not necessary to use expensive components such as a semiconductor sensor for detecting humidity, and the configuration can be made at low cost. Also, 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 performance of detecting moisture is reduced.
In the above description, as an application example of the moisture detection RFIC device 10, the case where the moisture detection RFIC device 10 is mounted on the diaper 30 has been described. However, the application example is not limited to the above application example. For example, the RFIC device 10 may be attached to the outside of a water pipe to detect water leakage, and used as an RFIC device for detecting water leakage. In addition, it may be configured to detect not only the presence / absence of moisture but also a dry / wet cycle when the moisture is dry.

(Embodiment 2)
FIG. 5 is a schematic perspective view showing the configuration of the moisture detecting RFIC device 10a according to the second embodiment.
The moisture detection RFIC device 10a according to the second embodiment is different from the moisture detection RFIC device according to the first embodiment in that the surfaces of the first and second antenna elements 11 and 12 are not holes but first and second antenna elements. The difference is that a groove 13a is provided along the longitudinal direction of the two antenna elements 11, 12. The layout of the grooves 13a may be provided on the front surface and / or the back surface similarly to the holes. The width of the groove 13a in the lateral direction is, for example, 50 to 200 μm. The layout of the grooves 13a may be uniform over the entire surface of the antenna element, for example. Alternatively, it may be concentrated near the edge of the antenna element. Further, the grooves 13a may be distributed line-symmetrically in each of the first and second antenna elements 11 and 12. Alternatively, the grooves 13a may be distributed point-symmetrically in each of the first and second antenna elements 11, 12. The groove 13a is preferably provided at an electric field concentration portion such as an end portion or a side end portion. The groove 13a itself is a portion where the electric field is concentrated. Further, by providing the groove 13a, the weight of the moisture detecting RFIC device 10 can be reduced. In this case, as in the case of the moisture detecting RFIC device according to the first embodiment, holding the moisture in the groove 13a changes the wireless communication state. Further, depending on the wireless communication state, wireless communication itself becomes impossible. Therefore, the presence of moisture can be detected by detecting a change in the wireless communication state.
The operation of changing the wireless communication state is the same as in the first embodiment, and a description thereof will not be repeated.

<Method of manufacturing RFIC device for detecting moisture>
The moisture detection RFIC device 10a is obtained by the following manufacturing method.
(1) A plurality of grooves 13a are formed on the surface of the first and second flat antenna elements 11 and 12. For example, a plurality of grooves 13a may be formed by laser processing the first and second antenna elements 11 and 12 made of copper foil. Alternatively, the grooves 13a may be formed by dicing the first and second antenna elements 11 and 12 made of copper foil. Further, the first and second antenna elements 11 and 12 made of copper foil may be grind-processed to form the grooves 13a. As for the ratio of the concave and convex portions of the groove, the ratio of the concave portion to the convex portion may be, for example, 1: 1.
(2) The first and second antenna elements 11 and 12 provided with the plurality of grooves 13a are connected to the RFIC element 1 to obtain the moisture detecting RFIC device 10. The connection between the first and second antenna elements 11 and 12 and the RFIC element 1 may be any of direct connection, capacitive coupling, magnetic field coupling, and the like.
Note that the surface of the antenna element may be subjected to a rust-preventive process to prevent oxidation.

(Embodiment 3)
FIG. 6 is a plan view showing the configuration of the moisture detection RFIC device 10b according to the third embodiment.
The moisture detecting RFIC device 10b according to the third embodiment is different from the moisture detecting RFIC devices according to the first and second embodiments in that the first and second antenna elements 11 and 12 are not provided with holes on the surface but on the side surfaces. The difference is that irregularities 13b composed of a plurality of triangular convex portions and concave portions therebetween are provided. The layout of the unevenness 13b may be provided on one side or both sides similarly to the hole. Also, for example, it may be uniform over the entire side surface of the antenna element. Alternatively, it may be concentrated near the edge of the antenna element. In addition, unevenness 13b may be distributed on each side surface of the first and second antenna elements 11 and 12 in line symmetry. Alternatively, irregularities 13b may be distributed point-symmetrically on the respective side surfaces of the first and second antenna elements 11 and 12. It is preferable that the unevenness 13b is provided at an electric field concentration portion such as an end portion or a side end portion. In addition, the unevenness 13b itself is a portion where the electric field is concentrated. Further, by providing the irregularities 13b, the weight of the moisture detecting RFIC device 10 can be reduced.
In this case, as in the case of the RFIC device for detecting moisture according to the first embodiment, the wireless communication state changes by retaining the moisture in the unevenness 13b. At this time, the wireless communication itself becomes impossible depending on the wireless communication state. Therefore, the presence of moisture can be detected by detecting a change in the wireless communication state.

<Method of manufacturing RFIC device for detecting moisture>
The moisture detection RFIC device 10b is obtained by the following manufacturing method.
(1) A plurality of irregularities 13b are formed on the side surfaces of the first and second flat antenna elements 11 and 12. For example, the first and second antenna elements 11 and 12 made of copper foil may be etched to form a plurality of irregularities 13b on the side surface. Alternatively, the first and second antenna elements 11 and 12 made of a copper foil may be laser-processed to form irregularities 13b on the side surfaces. Further, the first and second antenna elements 11 and 12 made of copper foil may be cut to form unevenness 13b on the side surfaces. As for the ratio of the unevenness, the ratio between the concave portion and the convex portion may be, for example, 1: 1.
(2) The first and second antenna elements 11 and 12 provided with the plurality of grooves 13a are connected to the RFIC element 1 to obtain the moisture detecting RFIC device 10. The connection between the first and second antenna elements 11 and 12 and the RFIC element 1 may be any of direct connection, capacitive coupling, magnetic field coupling, and the like.
Note that the surface of the antenna element may be subjected to a rust-preventive process to prevent oxidation.

(Embodiment 4)
FIG. 7 is a schematic cross-sectional view showing a cross-sectional structure of the moisture detecting RFIC device 10c according to the fourth embodiment.
The moisture detecting RFIC device 10c according to the fourth embodiment supports the RFIC element 1 and the first and second antenna elements 11 and 12 in comparison with the moisture detecting RFIC devices according to the first to third embodiments. The difference is that a water absorbing material 2 is further provided. When the water absorbing material 2 absorbs water, water is guided to the holes 13, the grooves 13a, or the irregularities 13b on the side surfaces of the first and second antenna elements 11, 12, and the holes 13, the grooves 13a, or the irregularities 13b on the side surfaces. Can retain moisture. The movement of water from the water-absorbing material 2 to the holes 13, the grooves 13a, or the unevenness 13b on the side surface is considered to be due to capillary action. By holding moisture in the hole 13, the groove 13a, or the unevenness 13b on the side surface, the wireless communication state of the antenna element changes. At this time, the wireless communication itself becomes impossible depending on the wireless communication state. Therefore, the presence of moisture can be detected by detecting a change in the wireless communication state.
As the water absorbing material 2, for example, a polymer water absorbing material (polymer-based water absorbing material) or the like can be used. An inorganic water absorbing material can also be used. In the case of the inorganic water-absorbing material, since the volume change is small, a porous water-absorbing material represented by clay is particularly preferable. The water-absorbing material 2 only needs to support, that is, mount the RFIC element 1 and the first and second antenna elements 11 and 12. Thereby, the water absorbing material 2 can also serve as the base sheet, and the thickness of the entire moisture detecting RFIC device can be reduced. Further, the water-absorbing material 2 does not need to have rigidity or the like by itself, but if it has rigidity, mechanical shock resistance can be improved. On the other hand, if the water absorbing material 2 is flexible, the moisture detecting RFIC device 10 can be attached to a curved surface.

(Embodiment 5)
FIG. 8 is a schematic sectional view showing a sectional structure of a moisture detecting RFIC device 10d according to the fifth embodiment.
The moisture detecting RFIC device 10d according to the fifth embodiment has difficulty in supporting the RFIC element 1 and the first and second antenna elements 11 and 12 when compared with the moisture detecting RFIC device according to the fourth embodiment. The difference is that a water absorbing material 2a is provided and a water absorbing material 4 is provided on the first and second antenna elements 11 and 12. In this case, the first and second antenna elements 11 and 12 are sandwiched between the hard water absorbing material 2a and the water absorbing material 4.
By using the hardly water-absorbing material 2a as the base sheet, the mechanical strength can be improved. The hardly water-absorbing material 2a is a member made of a material that hardly absorbs water or hardly absorbs water. As the hardly water-absorbing material 2a, for example, a film member or a thin plate member made of PET resin can be used. The water absorbing material 4 serves as a cover sheet for protecting the upper surface.
Contrary to the above, a water-absorbing material may be used as the base sheet, and a hardly water-absorbing material may be used as the cover sheet.

(Embodiment 6)
FIG. 9 is a schematic cross-sectional view showing a cross-sectional structure of the moisture detecting RFIC device 10e according to the sixth embodiment.
The moisture detecting RFIC device 10e according to the sixth embodiment is different from the moisture detecting RFIC device according to the fourth embodiment in that the water absorbing material 4 is further provided on the upper surfaces of the first and second antenna elements 11 and 12. Different. Since the upper and lower surfaces of the first and second antenna elements 11 and 12 are sandwiched between two layers of the water absorbing materials 2 and 4, the upper and lower surfaces of the water absorbing materials 2 and 4 gradually absorb water. Thereby, moisture can be retained in the holes 13 and the grooves 13a on the surfaces of the first and second antenna elements 11 and 12, or the unevenness 13b on the side surfaces. As a result, the wireless communication state changes. At this time, the wireless communication itself becomes impossible depending on the wireless communication state. Therefore, the presence of moisture can be detected by detecting a change in the wireless communication state. In this case, since the water absorbing materials 2 and 4 are provided on both upper surfaces of the antenna element, it is possible to easily retain the water and improve the performance of detecting the water.

(Embodiment 7)
FIG. 10 is a schematic cross-sectional view showing a cross-sectional structure of a moisture detecting RFIC device 10f according to the seventh embodiment.
The moisture detecting RFIC device 10f according to the seventh embodiment is different from the moisture detecting RFIC device according to the sixth embodiment in that the first and second antenna elements 11 and 12 further include a water absorbing material 2 The second embodiment is different from the first embodiment in that the first water absorption material 5a is provided on the upper surface of the first and second antenna elements 11 and 12, and the second water absorption material 5b is further provided on the upper surface of the water absorption material 4.
The water-absorbing material 2, the first and second antenna elements 11, 12, and the water-absorbing material 4 are interposed between the first and second hard-to-absorbent materials 5a and 5b. That is, both main surfaces of the moisture detecting RFIC device 10f are sandwiched between the hardly water-absorbing materials 5a and 5b, and both side surfaces in the short direction are covered with the hardly water-absorbing materials 5a and 5b. That is, the water absorbing material 2 and the water absorbing material 4 are exposed only in the longitudinal direction. Therefore, moisture enters only along the first and second antenna elements 11 and 12 in the longitudinal direction. In this case, the water absorption changes only gradually. Since the amount of water absorption changes stepwise in this way, the degree of water absorption can be detected stepwise.

(Embodiment 8)
FIG. 11 is a flowchart of a diaper changing method by periodic patrol using the handy type reader 40 according to the eighth embodiment. The diaper change flowchart is different from the diaper change flowchart of FIG. 4 in that the flow is not ended so that the diaper change is performed repeatedly instead of being completed by one diaper change. . That is, the diaper can be changed any number of times in accordance with the actual state.
(1) The care-requiring person wears the diaper 30 to which the moisture detection RFIC device 10 has been mounted (S11).
(2) The caregiver applies the handy type reader 40 to the diaper of the care-requiring person to read the moisture detecting RFIC device 10 during the regular diaper changing tour (S12).
(3) It is determined whether communication with the moisture detecting RFIC device 10 is possible (S13). If communication is possible (YES), it means that moisture does not yet exist in the diaper, and the diaper is not replaced (S14). ), The process returns to the reader reading (S12) during the regular diaper change patrol. On the other hand, if communication with the moisture detection RFIC device 10 is impossible (NO), moisture is present in the diaper 30, that is, urine or stool is present. Therefore, the process moves to the next step S15.
(4) The care giver removes the diaper 30 of the care recipient (S15), and the care giver wears a new diaper to which the moisture detection RFIC device 10 is attached (S16).
(5) Immediately after changing the diaper, the reader is brought into contact with the diaper to read the RFID device for moisture detection (S17). Thereafter, the process proceeds to step S13 to determine whether communication with the moisture detection RFIC device 10 is possible. By reading the RFID device immediately after changing the diaper, an initial failure of the RFID can be detected. In this case, the flow does not end even if the diaper is changed.
Note that the RFID device may not be read immediately after the diaper change, and the process may return to the reader reading (S12) during the regular patrol of the diaper change. That is, the reading of the RFID device immediately after the diaper change may be omitted.
As described above, the diaper can be changed by regular patrol using the handy type reader 40. Further, in this flowchart, the diaper change can be repeated as many times as necessary according to the actual state.

  When used as an RFID tag, the moisture detection RFIC device may be used in any band such as the LF band, the HF band, the UHF band, and the SHF band. Further, the RFIC device for detecting moisture is typically an RFID tag, but is not limited to a device having a so-called tag function, and has another function such as a device having a reader / writer function. Is also good.

  Note that the present disclosure includes appropriately combining arbitrary embodiments and / or examples among the various embodiments and examples described above, and each embodiment and / or example is included. The effect which has can be exhibited.

  The RFIC device for moisture detection according to the present invention has holes or irregularities capable of retaining moisture on the surface or side surface of the flat antenna element. Therefore, moisture can be detected easily and with high accuracy, and is useful for detecting moisture in diapers, detecting leaks in piping, and the like.

DESCRIPTION OF SYMBOLS 1 RFIC element 2 Water absorbing material 2a Poor water absorbing material 4 Water absorbing material 5a, 5b Poor water absorbing material 6 Capacitor 10, 10a, 10b, 10c, 10d, 10e, 10f RFIC device 11 for moisture detection 11 First antenna element 12 Second antenna element 13 Hole 13a Groove 13b Unevenness 21 RFIC chip 22 Conductive bonding material 23 Terminal electrode 24 Sealing resin 25 Multilayer substrate 26 Terminal electrode 30 Diaper 40 Reader

Claims (7)

An RFIC element;
A planar conductor antenna element connected to the RFIC element;
With
The antenna element may have a hole or irregularities can retain water on the surface or side,
An RFIC device for detecting moisture , wherein the hole or the unevenness is provided in an electric field concentration portion .   2. The moisture detecting RFIC device according to claim 1, wherein the antenna element includes a groove along a longitudinal direction of a surface.   The RFIC device for detecting moisture according to claim 1, wherein the antenna element includes irregularities on a side surface.   The RFIC device for moisture detection according to any one of claims 1 to 3, wherein the antenna element includes a first antenna element and a second antenna element connected to the RFIC element and extending in different directions. .   The RFIC device for detecting moisture according to any one of claims 1 to 4, further comprising a water-absorbing material that supports the antenna element and faces the hole or the unevenness. A hardly water-absorbing material supporting the antenna element,
While sandwiching the antenna element between the hardly water-absorbing material, and a water-absorbing material provided to face the hole or unevenness,
The RFIC device for detecting moisture according to any one of claims 1 to 4, further comprising:   The RFIC device for moisture detection according to claim 5, further comprising two hardly water-absorbing materials sandwiching the upper and lower water absorbing materials sandwiching the antenna element from above and below.

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