JP2016170070A - Moisture-detecting rfic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a moisture-detecting device that can detect the presence of moisture easily and accurately.SOLUTION: The moisture-detecting RFIC device includes an RFIC element 1 and a plate-like antenna element connected to the RFIC element and having a hole 13 or a convexo-concave part holding moisture in a front surface and a side surface thereof.SELECTED DRAWING: Figure 1

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 temperature detecting semiconductor sensor in order to detect moisture.

  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.

  Further, there is known a moisture detection sensor in which the periphery of a wireless IC tag is covered with a covering means having water absorption (see, for example, 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 and an epoxy resin in which polyvinyl alcohol is dispersed are listed. Small and limited area of use of insulating material. 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.

  In the moisture detection sensor described in Patent Document 2, it is necessary to cover the periphery of the wireless IC tag with water absorption and to cover with an electromagnetic wave transmitting water absorbing material. For this reason, there has been a drawback that the product size becomes larger than a product without a moisture detection function. In addition, since a substance having water absorbency absorbs water to realize a communication disabled state, there is a problem that 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 moisture detection device that can detect the presence of moisture with ease and high accuracy.

An RFIC device for moisture detection according to the present invention includes an RFIC element,
A planar antenna element connected to the RFIC element;
With
The antenna element has holes or irregularities that can retain moisture on the surface or side surfaces.

  Since the RFIC device for moisture detection according to the present invention has holes or irregularities that can retain 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. As a result, 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 a water | moisture content detection which concerns on Embodiment 1, (b) is a side view of (a), (c) is a plane of (a) FIG. 6C is an equivalent circuit diagram of the moisture detection RFIC device 10 according to the first embodiment. (A) is a schematic sectional drawing which shows the cross-section of an RFIC element, (b) is an equivalent circuit schematic of (a). It is the schematic which shows the example of application which mounted | wore the diaper with the water | moisture-content detection RFIC device which concerns on Embodiment 1. FIG. It is a flowchart of the diaper replacement | exchange in the example of use which mounted | wore the diaper with the moisture detection RFIC device of FIG. FIG. 5 is a schematic perspective view showing a configuration of a moisture detection RFIC device according to a second embodiment. 6 is a plan view showing a configuration of a moisture detection RFIC device according to Embodiment 3. FIG. FIG. 6 is a schematic cross-sectional view showing a cross-sectional structure of a moisture detection RFIC device according to a fourth embodiment. FIG. 9 is a schematic cross-sectional view showing a cross-sectional structure of a moisture detection RFIC device according to a fifth embodiment. FIG. 10 is a schematic cross-sectional view showing a cross-sectional structure of a moisture detection RFIC device according to a sixth embodiment. FIG. 10 is a schematic cross-sectional view showing a cross-sectional structure of a moisture detection RFIC device according to a seventh embodiment. It is a flowchart of the diaper replacement | exchange method by the regular patrol which concerns on Embodiment 8. FIG.

The RFIC device for moisture detection according to the first aspect includes an RFIC element,
A planar antenna element connected to the RFIC element;
With
The antenna element has holes or irregularities that can retain moisture on the surface or side surfaces.

  According to the above configuration, since the surface or side surface of the flat antenna element has a hole or unevenness that can hold moisture, holding the moisture in the hole or unevenness changes the resonance frequency of the antenna element, thereby 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 the second aspect, in the first aspect, the antenna element may include a groove along the longitudinal direction of the surface.

  According to the above configuration, holding the moisture in the groove changes the resonance frequency of the antenna element, thereby changing the wireless communication state. 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 the third aspect, in the first aspect, the antenna element may include unevenness on a side surface.

  According to the above configuration, by holding moisture in the unevenness on the side surface, 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.

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

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

  The RFIC device for moisture detection according to a fifth aspect of the present invention 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 face the hole or the unevenness. You may prepare.

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

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

  According to the said structure, a hardly water-absorbing material can be used as the base material sheet which supports an antenna element, and mechanical strength can be improved.

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

  According to the above configuration, since the antenna element and the water absorbing material are sandwiched between the first hardly water-absorbing material and the second hardly water-absorbing material, moisture can enter only along the longitudinal direction of the antenna element. Not come. In this case, the moisture absorption amount changes only gradually, and the antenna length also changes only gradually. In this way, the electrical length of the antenna element changes step by step, so that the degree of water absorption can be detected step by step.

  Hereinafter, an RFIC device for moisture detection 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 detection 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 detection RFIC device 10 according to the first embodiment.
The moisture detection RFIC device 10 according to the first embodiment includes an RFIC element 1 and first and second antenna elements 11 and 12 that are connected to the RFIC element and extend in opposite directions. In FIG. 1, the 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. The first and second antenna elements 11 and 12 have a plurality of holes 13 that can retain moisture on their surfaces. The mechanism for retaining moisture by the holes 13 is considered to be due to, for example, a capillary phenomenon. The hole 13 may be a through hole or a half through hole. 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 be uniform over the entire surface of the antenna element, for example. Or you may concentrate on the vicinity of the edge part of an antenna element. Further, the holes 13 may be distributed in line symmetry in the first and second antenna elements 11 and 12 respectively. 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 in 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. Further, by providing the hole 13, the weight of the moisture detection RFIC device 10 can be reduced.
As shown in the equivalent circuit diagram of FIG. 1C, the moisture detection 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 moisture detecting RFIC device 10 can wirelessly communicate when moisture is not present, but in an environment where moisture is present, the moisture detecting RFIC device 10 is inserted into the holes 13 provided on the surfaces of the first and second antenna elements 11 and 12. By holding moisture, the wireless communication state changes. Depending on the wireless communication state, wireless communication itself may not be possible. The case where the wireless communication state changes by holding moisture in the holes 13 provided on the surfaces of the first and second antenna elements 11 and 12 is, for example, due to a change in capacity due to holding moisture in the holes. This is a case where the communicable distance of the moisture detecting RFIC device 10 changes. Furthermore, wireless communication itself may be impossible depending on the wireless communication state. Alternatively, the case where the wireless communication state changes is a case where the electric frequency of the antenna changes and the carrier frequency changes. In this case, wireless communication itself may be impossible. Further, the wireless communication state may change due to the change in the power of wireless communication. Also in this case, wireless communication itself may be impossible due to 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 cross-sectional view showing a cross-sectional structure of the RFIC element 1, and FIG. 2B 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. By providing the feeding circuit in this way, the center frequency of the carrier frequency can be prevented from changing greatly even if the electrical length of the antenna changes.
In other words, if the electrical length of the antenna element in the initial state is adjusted to the maximum gain state (2 / λ), the amount of water absorption increases, and even if the electrical length of the antenna element changes, the communicable distance only decreases. Reading at the same carrier frequency is possible. Therefore, the degree of water absorption can also 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, direct connection with 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 coupled not only by direct connection but also by any combination 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 a built-in power supply circuit. However, the present invention is not limited to this, and the power supply circuit may not be provided. By not providing the power feeding circuit, holding the moisture in the holes 13 provided on the surfaces of the first and second antenna elements 11 and 12 changes the electric length of the antenna and changes the carrier frequency, thereby changing the wireless communication state. Can be changed. Furthermore, wireless communication itself can be made impossible. 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 antenna elements extending in opposite directions with the RFIC element 1 as the center. 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. 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 surfaces. The arrangement of the surface holes 13 is not limited to a point-symmetric arrangement as shown in the plan view of FIG. 1C, and may be a line-symmetric arrangement. Alternatively, an asymmetrical arrangement may be used.
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.
In addition, the antenna element surface can be considered in two ways, for example, a structure in which the surface is sealed with polyimide or the like and a surface treatment such as a rust prevention treatment without sealing the surface. Furthermore, hydrophilic treatment may be performed on the surface of the antenna element.

<Method for producing RFIC device for moisture detection>
The moisture detection RFIC device 10 is obtained by the following manufacturing method.
(1) A plurality of holes 13 are formed on the surfaces of the flat plate-like first and second 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 first and second antenna elements 11 and 12 made of copper foil may be laser processed to form the plurality of holes 13. In addition, the area ratio of the part which does not provide the hole 13 and the hole 13 may be 1: 1, for example.
(2) The RFIC device 1 for moisture detection is obtained by connecting the first and second antenna elements 11 and 12 provided with the plurality of holes 13 to the RFIC element 1. 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.
The surface of the antenna element may be subjected to rust prevention processing to prevent oxidation.

FIG. 3 is a schematic diagram illustrating an application example in which the moisture detecting RFIC device 10 according to the first embodiment is mounted on the diaper 30.
As shown in FIG. 3, when moisture due to urine or the like is generated in the diaper 30 in which the moisture detecting RFIC device 10 according to the first embodiment is attached to 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, the antenna length is changed, and the communication distance is shortened. Furthermore, wireless communication itself cannot be performed due to a change in the wireless communication state. By performing wireless communication with the RFIC device 10 from the outside by the reader / writer 40, detection of a communication distance capable of wireless communication with the RFIC device 10 attached to the diaper 30, and counting of the number of successful wireless communication, the RFIC device 10 It is possible to detect the presence of moisture.

FIG. 4 is a flowchart of diaper replacement in an application example in which the moisture detection RFIC device 10 of FIG. 3 is attached to the diaper 30.
(1) A care recipient wears the diaper 30 on which the moisture detection RFIC device 10 is worn, and performs pairing between the caregiver and the diaper 30 (S01).
(2) Next, reading is first performed by the reader 40 of the moisture detection RFIC device 10 (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 certain time has elapsed since the previous reading (S03). If the certain time has not elapsed (NO), the process returns to repeat this determination until the certain time has elapsed. The fixed time is, for example, about 30 seconds. When a certain time has elapsed (YES), the process proceeds to the next step.
(3) Reading is performed by the reader 40 of the moisture detection RFIC device 10 (S04).
(4) It is determined whether or not communication with the moisture detection RFIC device 10 is possible (S05), and if communication is possible (YES), it means that there is no moisture in the diaper yet. Return to the determination of the passage of time (S03). On the other hand, if communication with the moisture detection RFIC device 10 is impossible (NO), moisture, i.e., urine or stool is present in the diaper 30. Therefore, the process proceeds to the next step S06.
(5) The moisture state in the diaper 30 is displayed on the reader 40 (S06). The caregiver may have a communication module or the like different from the reader 40, and information may be transmitted from the reader 40 to the communication module. 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.
(6) Thereafter, the caregiver removes the diaper 30, and the care recipient wears a new diaper on which the moisture detection RFIC device 10 is attached.
The diaper exchange in the application example in which the moisture detecting RFIC device 10 is attached to the diaper 30 is performed as described above. In addition, in the said flowchart, since the flow of one diaper replacement | exchange is shown typically, the flow is complete | finished by 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 a wet state due to urine or stool or sweat. 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 lowered.
In addition, although the case where the moisture detection RFIC device 10 is mounted on the diaper 30 has been described as an application example of the moisture detection RFIC device 10, the application 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. In addition, it may be configured not only to detect the presence or absence of moisture, but also to detect a wet / dry cycle with moisture in a dry state.

(Embodiment 2)
FIG. 5 is a schematic perspective view showing the configuration of the moisture detecting RFIC device 10a according to the second embodiment.
Compared with the moisture detection RFIC device 10a according to the first embodiment, the moisture detection RFIC device 10a according to the second embodiment is not a hole on the surface of the first and second antenna elements 11 and 12, but the first and second The difference is that a groove 13 a is provided along the longitudinal direction of the two antenna elements 11 and 12. The layout of the grooves 13a may also be provided on the front surface and / or the back surface in the same manner as the holes. The width of the groove 13a in the short 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. Or you may concentrate on the vicinity of the edge part of an antenna element. Further, the grooves 13a may be distributed in line symmetry in the first and second antenna elements 11 and 12, respectively. Alternatively, the grooves 13a may be distributed point-symmetrically in the first and second antenna elements 11 and 12, respectively. The groove 13a is preferably provided in an electric field concentration portion such as an end portion or a side end portion. The groove 13a itself becomes a portion where the electric field concentrates. Moreover, weight reduction of the moisture detection RFIC device 10 can be realized by providing the groove 13a. Also in this case, similarly to the moisture detection RFIC device according to the first embodiment, the wireless communication state is changed by holding moisture in the groove 13a. Further, depending on the state of wireless communication, wireless communication itself becomes impossible. Therefore, the presence of moisture can be detected by detecting a change in the wireless communication state.
In addition, since the effect | action which a radio | wireless communication state changes is the same as that of the case of Embodiment 1, description is abbreviate | omitted.

<Method for producing RFIC device for moisture detection>
The moisture detection RFIC device 10a is obtained by the following manufacturing method.
(1) A plurality of grooves 13 a are formed on the surfaces of the flat plate-like first and second antenna elements 11 and 12. For example, the first and second antenna elements 11 and 12 made of copper foil may be laser processed to form a plurality of grooves 13a. Alternatively, the groove 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 grinded to form the groove 13a. The ratio of the concave and convex portions of the grooves may be 1: 1, for example, as the ratio between the concave portions and the convex portions.
(2) The RFIC device 10 for moisture detection is obtained by connecting the first and second antenna elements 11 and 12 provided with the plurality of grooves 13 a to the RFIC element 1. 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.
The surface of the antenna element may be subjected to rust prevention processing to prevent oxidation.

(Embodiment 3)
FIG. 6 is a plan view showing the configuration of the moisture detecting RFIC device 10b according to the third embodiment.
When compared with the moisture detection RFIC device according to the first and second embodiments, the moisture detection RFIC device 10b according to the third embodiment is not formed on the surface of the first and second antenna elements 11 and 12 but on the side surface. The difference is that an uneven portion 13b including a plurality of triangular convex portions and concave portions therebetween is provided. The layout of the unevenness 13b may also be provided on one side surface or both side surfaces similarly to the holes. For example, it may be uniform over the entire side surface of the antenna element. Or you may concentrate on the vicinity of the edge part of an antenna element. The unevenness 13b may be distributed symmetrically on the side surfaces of the first and second antenna elements 11 and 12, respectively. Alternatively, the unevenness 13 b may be distributed point-symmetrically on the side surfaces of the first and second antenna elements 11 and 12. The irregularities 13b are preferably provided in electric field concentration portions such as end portions and side end portions. In addition, the unevenness | corrugation 13b becomes a part into which an electric field concentrates itself. Further, by providing the unevenness 13b, the weight of the moisture detecting RFIC device 10 can be reduced.
Also in this case, as in the case of the moisture detection RFIC device according to the first embodiment, the wireless communication state changes by holding moisture in the unevenness 13b. At this time, 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 for producing RFIC device for moisture detection>
The moisture detection RFIC device 10b is obtained by the following manufacturing method.
(1) A plurality of irregularities 13 b are formed on the side surfaces of the flat plate-like first and second 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 surfaces. Alternatively, the first and second antenna elements 11 and 12 made of copper foil may be laser processed to form the unevenness 13b on the side surface. Furthermore, the first and second antenna elements 11 and 12 made of copper foil may be cut to form the unevenness 13b on the side surface. The ratio of the unevenness may be 1: 1, for example, as the ratio of the concave portion to the convex portion.
(2) The RFIC device 10 for moisture detection is obtained by connecting the first and second antenna elements 11 and 12 provided with the plurality of grooves 13 a to the RFIC element 1. 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.
The surface of the antenna element may be subjected to rust prevention processing 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 detection RFIC device 10c according to the fourth embodiment supports the RFIC element 1 and the first and second antenna elements 11 and 12 when compared with the moisture detection RFIC device according to the first to third embodiments. It is different in that the water absorbing material 2 is further provided. When the water absorbing material 2 absorbs water, the water is guided to the holes 13, the grooves 13 a, or the side irregularities 13 b on the surfaces of the first and second antenna elements 11, 12, and the holes 13, the grooves 13 a, or the side irregularities 13 b are introduced. Can retain moisture. It is considered that the movement of moisture from the water absorbing material 2 to the hole 13, the groove 13a, or the side surface unevenness 13b is due to a capillary phenomenon. By holding moisture in the hole 13, the groove 13 a, or the unevenness 13 b on the side surface, the wireless communication state of the antenna element changes. At this time, 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 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 moisture detection 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 is flexible, the moisture detecting RFIC device 10 can be attached to a curved surface.

(Embodiment 5)
FIG. 8 is a schematic cross-sectional view showing a cross-sectional structure of a moisture detection RFIC device 10d according to the fifth embodiment.
The moisture detection RFIC device 10d according to the fifth embodiment is difficult to support the RFIC element 1 and the first and second antenna elements 11 and 12 when compared with the moisture detection RFIC device according to the fourth embodiment. A difference is that a water absorbing material 2 a 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 hardly water-absorbing material 2 a and the water-absorbing material 4.
By using the hardly water-absorbing material 2a as a base sheet, the mechanical strength can be improved. The hardly water-absorbing material 2a is a member made of a material that hardly absorbs moisture or hardly absorbs moisture. 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 that protects 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 a moisture detection RFIC device 10e according to the sixth embodiment.
When compared with the moisture detection RFIC device according to the fourth embodiment, the moisture detection RFIC device 10e according to the sixth embodiment is further provided with a water absorbing material 4 on the upper surfaces of the first and second antenna elements 11 and 12. Is different. Since the upper and lower surfaces of the first and second antenna elements 11 and 12 are sandwiched between the two layers of the water absorbing materials 2 and 4, the water absorbing materials 2 and 4 on the upper and lower surfaces gradually absorb moisture. Thus, moisture can be held in the holes 13 on the surface of the first and second antenna elements 11, 12, the grooves 13 a, or the unevenness 13 b on the side surfaces. As a result, the wireless communication state changes. At this time, 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 the upper and lower surfaces of the antenna element, it is easy to hold moisture, and the moisture detection performance can be improved.

(Embodiment 7)
FIG. 10 is a schematic cross-sectional view showing a cross-sectional structure of a moisture detection RFIC device 10f according to the seventh embodiment.
When compared with the moisture detection RFIC device according to the sixth embodiment, the moisture detection RFIC device 10f according to the seventh embodiment is further provided on the lower surface of the water absorbing material 2 on the lower surfaces of the first and second antenna elements 11 and 12. 1 in that it is provided with one hardly water-absorbing material 5a, and further provided with a second hardly water-absorbing material 5b on the upper surface of the water-absorbing material 4 on the upper surface of the first and second antenna elements 11 and 12.
The water absorbing material 2, the first and second antenna elements 11, 12 and the water absorbing material 4 are sandwiched between the first hardly water absorbing material 5a and the second hardly water absorbing material 5b. That is, both main surfaces of the moisture detection RFIC device 10f are sandwiched between the hardly water-absorbing materials 5a and 5b, and both side surfaces in the short direction are also 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 longitudinal direction of the first and second antenna elements 11 and 12. In this case, the water absorption amount changes only gradually. In this way, the amount of water absorption changes stepwise, so that 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. This diaper exchange flowchart is different from the diaper exchange flowchart of FIG. 4 in that the flow is not terminated by one diaper exchange, but the flow is not terminated repeatedly. . That is, the diaper can be changed any number of times according to the actual state.
(1) A care recipient wears the diaper 30 with the moisture detecting RFIC device 10 (S11).
(2) During a regular tour of changing diapers, the caregiver applies the handy type reader 40 to the diaper of the care recipient and reads the moisture detection RFIC device 10 (S12).
(3) It is determined whether or not communication with the moisture detection RFIC device 10 is possible (S13). If communication is possible (YES), it means that there is no moisture in the diaper, and no diaper replacement is performed (S14). ) Return to the reader reading (S12) at the regular tour of changing diapers. On the other hand, if communication with the moisture detection RFIC device 10 is impossible (NO), moisture, i.e., urine or stool is present in the diaper 30. Therefore, the process proceeds to the next step S15.
(4) The caregiver removes the diaper 30 of the care recipient (S15), and the care recipient wears a new diaper on which the moisture detection RFIC device 10 is attached (S16).
(5) Immediately after changing the diaper, the reader is put on the diaper and the RFID device for moisture detection is read (S17). Thereafter, the process proceeds to step S13 where it is determined whether communication with the moisture detection RFIC device 10 is possible. By thus reading the RFID device immediately after changing the diaper, it is possible to detect an initial failure of the RFID. 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 changing the diaper, but may be returned to the reader reading (S12) when the diaper is changed periodically. That is, reading of the RFID device immediately after changing the diaper may be omitted.
As described above, the diaper can be changed by regular patrol using the handy type reader 40. In this flowchart, the diaper replacement can be repeated as many times as necessary in accordance with the actual state.

  Note that the moisture detecting RFIC device 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 for moisture detection is typically an RFID tag, but is not limited to a so-called tag function, and has other functions such as a reader / writer function. Also good.

  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.

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

DESCRIPTION OF SYMBOLS 1 RFIC element 2 Water absorbing material 2a Hard water absorbing material 4 Water absorbing material 5a, 5b Hard water absorbing material 6 Capacitor 10, 10a, 10b, 10c, 10d, 10e, 10f Moisture detection RFIC device 11 First antenna element 12 Second antenna element 13 Hole 13a Groove 13b Concavity and convexity 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 antenna element connected to the RFIC element;
With
The antenna element is an RFIC device for moisture detection having a hole or an unevenness capable of holding moisture on the surface or side surface.   The RFIC device for moisture detection according to claim 1, wherein the antenna element includes a groove along a longitudinal direction of a surface.   The RFIC device for moisture detection according to claim 1, wherein the antenna element includes unevenness on a side surface.   4. The moisture detecting RFIC device according to claim 1, wherein the antenna element includes a first antenna element and a second antenna element that are connected to the RFIC element and extend in different directions. 5. .   5. The moisture detection RFIC device according to claim 1, further comprising a water absorbing material that supports the antenna element and faces the hole or the unevenness. 6. A poorly water-absorbing material that supports the antenna element;
While sandwiching the antenna element between the hardly water-absorbing material, and the water-absorbing material provided to face the hole or unevenness,
The RFIC device for moisture detection according to any one of claims 1 to 4, further comprising:   The moisture detecting RFIC device according to claim 5, further comprising two hard-water-absorbing materials sandwiching the upper and lower water-absorbing materials sandwiching the antenna element from above and below.

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