JP2010140086A - Rfid tag unit and concrete product equipped with the same, concrete structure and method for fixing rfid tag - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an RFID tag unit for extending a communication range, and easily, accurately, reliably, and efficiently recognizing a concrete product or the like, a concrete product equipped with the same, a concrete structure, and a method for fixing the RFID tag. <P>SOLUTION: The RFID tag unit 1 includes: an RFID tag 15 suspended by using a fixed pin 14 in a casing 13, whose end in the longitudinal direction is held by a positioning protrusion 17, and fixed in the casing 13; a reflector 16 installed on a bottom face 12a; an air layer 19 formed between the upper face of the RFID tag 15 and a bottom face 11a of a box body 11; and an air layer 20 formed between the lower face of the RFID tag 15 and a bottom face 12a of a box body 12. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an RFID tag unit, a concrete product including the RFID tag unit, a concrete structure, and a method for fixing an RFID tag. More specifically, the communication distance can be increased, and various products such as a concrete product can be recognized. The present invention relates to an RFID tag unit, a concrete product including the RFID tag unit, a concrete structure, and a method for fixing the RFID tag.

Conventionally, in concrete products such as L-shaped retaining walls, box culverts, precast concrete plates, U-grooves, and fume pipes, it is difficult to obtain information on concrete products. It is often difficult to follow up from.
Moreover, regarding concrete structures such as reinforced concrete structures and assembling-type concrete structures, it is often difficult to follow up on the concrete information used at the time of construction.
Therefore, in order to solve such problems, there has been proposed a concrete product to which an RFID (Radio Frequency Identification) system that is a non-contact wireless communication system is applied (Patent Document 1).
This concrete product is an RFID tag installed with the antenna directing direction facing the outer peripheral surface at a position retracted to the inside from the outer peripheral surface of a concrete building material made of concrete such as a fume tube. The RFID tag data is written and read by wireless communication with an RFID device provided outside the concrete product.

In the RFID tag embedded in the concrete product, radio waves of 13.56 MHz band are mainly used. The reason is that since the size of the antenna depends on the frequency of the radio wave used, the use of radio waves having a high frequency makes it possible to downsize the entire RFID tag. On the other hand, when a radio wave having a high frequency such as a GHz band is used, there is a drawback that the attenuation rate of the radio wave in the concrete or in water is increased and communication becomes unstable.
In this way, considering the frequency band that satisfies both the miniaturization of the entire RFID tag and the stabilization of communication, the 13.56 MHz band radio wave is suitable.
JP 2000-91963 A

However, when a conventional 13.56 MHz band RFID tag is embedded in concrete, the communication distance for stably transmitting and receiving information is about 3 cm, depending on the output of the reader / writer. The depth at which this RFID tag can be embedded in concrete is about 3 cm.
Therefore, if the RFID tag is simply embedded in the concrete, there is a possibility that the depth of the RFID tag in the concrete is fixed at a position deeper than the communicable depth. In this case, transmission / reception with the RFID tag becomes impossible, and a desired purpose may not be achieved, and the RFID tag becomes useless and uneconomical.

  On the other hand, even when the RFID tag is fixed within a communicable depth range, an RFID tag with a short communication distance transmits and receives information unless a reader / writer is applied to a very narrow area of the concrete surface. There is a problem that it is difficult to find an RFID tag in concrete.

  The present invention has been made in order to solve the above-described problems, and can provide a long communication distance. Furthermore, in addition to a concrete product or a concrete structure, the present invention is provided in a product or a structure of another material. RFID tag unit that can take a long communication distance and recognize various products and structures easily, accurately, reliably and efficiently, and a concrete product and a concrete structure equipped with the RFID tag unit It is an object to provide a method for fixing an object and an RFID tag.

  As a result of intensive studies to solve the above problems, the present inventors fixed the RFID tag in the casing, and provided a conductive member on the bottom surface of the casing or the outer surface on the lower side of the casing. A first layer made of a material having a relative dielectric constant of 8 or less is provided between the upper surface of the RFID tag and the upper surface in the housing, and the relative dielectric constant is 8 between the lower surface of the RFID tag and the bottom surface in the housing. If an RFID tag unit is provided by providing a second layer made of the following substances, the communication distance between the RFID tag unit and an external device can be increased longer than before, and furthermore, the RFID tag unit. The present inventors have found that recognition of concrete products and the like provided with can be performed simply, accurately, reliably and efficiently, and have completed the present invention.

  That is, the RFID tag unit of the present invention fixes the RFID tag in the housing, and provides a conductive member on the bottom surface of the housing or the outer surface on the lower side of the housing, and the top surface of the RFID tag and the inside of the housing A first layer made of a material having a relative dielectric constant of 8 or less is provided between the upper surface and a first layer made of a material having a relative dielectric constant of 8 or less between the lower surface of the RFID tag and the bottom surface of the housing. Two layers are provided.

In this RFID tag unit, a first layer made of a material having a relative dielectric constant of 8 or less is provided between the upper surface of the RFID tag and the upper surface in the housing, and between the lower surface of the RFID tag and the bottom surface in the housing. By providing the second layer made of a material having a relative dielectric constant of 8 or less, the RFID tag is sandwiched between layers made of a material having a relative dielectric constant of 8 or less, thereby reducing radio wave attenuation. Is possible.
In addition, by providing a conductive member on the bottom surface inside the casing or the outer surface below the casing, the conductive member enhances the reflection function of reflecting radio waves, thereby reducing the attenuation of radio waves. Is possible.
As described above, the communicable distance can be increased.

In the RFID tag unit of the present invention, the first layer includes one or more selected from the group of gas, foamable material, and resin, and the second layer includes the first layer and the first layer. It consists of 1 type, or 2 or more types selected from the group of different gas, a foamable material, and resin.
Here, “the second layer is different from the first layer” only requires that at least one substance having a relative dielectric constant of 8 or less used for each layer is different.

  In this RFID tag unit, since the first layer and the second layer are different from each other, the radio waves of the RFID tag unit can be selected by separately selecting the first layer and the second layer. It is possible to further reduce the attenuation rate of the radio wave, thereby further reducing the attenuation of the radio wave.

The RFID tag unit of the present invention is characterized in that both the first layer and the second layer are made of one or more selected from the group of gas, foamable material, and resin.
In this RFID tag unit, the first layer and the second layer are the same, and the first layer and the second layer are made to coincide with each other. It is possible to reduce the difference between the two.

  The RFID tag unit of the present invention is characterized in that the RFID tag is fixed in the casing by suspending the RFID tag in the casing with a fixture.

  In this RFID tag unit, the RFID tag is suspended in the casing by suspending the RFID tag in the casing by a fixing tool, so that the RFID tag is suspended in the space in the casing. The space between the bottom of the body can be made larger, and the effect of providing the conductive member can be further exhibited. Therefore, the attenuation of radio waves can be further reduced.

The RFID tag unit of the present invention is characterized in that a fixture is provided outside the casing.
In this RFID tag unit, by providing a fixture on the outside of the housing, the RFID tag unit can be easily attached to a desired structure via the fixture.

The concrete product of the present invention comprises the RFID tag unit of the present invention.
In this concrete product, the RFID tag unit of the present invention is provided, so that the concrete product can be recognized simply, accurately, reliably and efficiently by taking a long communication distance.

The concrete structure of the present invention comprises the RFID tag unit of the present invention.
In this concrete structure, the RFID tag unit of the present invention is provided, so that it is possible to recognize the concrete structure simply, accurately, reliably and efficiently by taking a long communication distance.

  The RFID tag fixing method of the present invention is a method of fixing an RFID tag in a recess formed in a structure, product or member, and a conductive member is fixed or arranged on the bottom surface of the recess, and this conductive property is fixed. A second layer made of a material having a relative dielectric constant of 8 or less is formed on the member, and the RFID tag is fixed or arranged so as to be embedded on the second layer or the second layer, and on the RFID tag A first layer made of a material having a relative dielectric constant of 8 or less is formed.

  In this RFID tag fixing method, a conductive member is fixed or arranged on the bottom surface of a recess formed in a structure, product, or member, and a second dielectric material having a relative dielectric constant of 8 or less is formed on the conductive member. Forming a layer, fixing or arranging the RFID tag so as to be embedded on or in the second layer, and forming a first layer made of a material having a relative dielectric constant of 8 or less on the RFID tag. By forming, a structure, a product, or a member provided with an RFID tag having a small radio wave attenuation rate can be obtained.

  According to the RFID tag unit of the present invention, the RFID tag is fixed in the casing, and a conductive member is provided on the bottom surface in the casing or the outer surface on the lower side of the casing. The upper surface of the RFID tag, the upper surface in the casing, Is provided with a first layer made of a material having a relative dielectric constant of 8 or less, and a second layer made of a material having a relative dielectric constant of 8 or less is provided between the lower surface of the RFID tag and the bottom surface of the housing. Therefore, the attenuation of radio waves can be reduced as compared with the case where the RFID tag is used alone, so that the communicable distance can be increased as compared with the conventional case. Therefore, transmission / reception between the RFID tag unit and the external device can be performed simply, accurately, reliably and efficiently.

  Furthermore, since the RFID tag, the conductive member, the first layer, and the second layer are integrated, they should be installed by embedding, mounting, etc. in concrete products, concrete structures, and other materials and structures. In this case, the RFID tag is not damaged.

  According to the concrete product of the present invention, since the RFID tag unit of the present invention is provided, the communicable distance can be made longer than before, and therefore, the RFID tag unit in the concrete product and the external device The transmission / reception can be performed easily, accurately, reliably and efficiently.

  According to the concrete structure of the present invention, since the RFID tag unit of the present invention is provided, the communicable distance can be increased as compared with the conventional structure. Therefore, the RFID tag unit and the external device in the concrete structure can be taken. Can be transmitted, received, and transmitted simply and accurately, reliably and efficiently.

  According to the RFID tag fixing method of the present invention, a conductive member is fixed or arranged on the bottom surface of a recess formed in a structure, product or member, and a material having a relative dielectric constant of 8 or less is formed on the conductive member. A second layer is formed, the RFID tag is fixed or disposed on the second layer or embedded in the second layer, and a second dielectric layer having a relative dielectric constant of 8 or less is formed on the RFID tag. Since one layer is formed, a structure, product, or member including an RFID tag with a small radio wave attenuation rate can be easily obtained.

The best mode for carrying out an RFID tag unit and a concrete product, a concrete structure, and an RFID tag fixing method according to the present invention will be described with reference to the drawings.
Note that this embodiment is specifically described for better understanding of the gist of the invention, and does not limit the present invention unless otherwise specified.

“First Embodiment”
1 is a plan view showing an RFID tag unit according to a first embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line AA in FIG. 1, and FIG. 3 is a cross-sectional view taken along line BB in FIG. It is.
In this embodiment, a concrete product in which the RFID tag unit is attached to a reinforcing bar of a concrete body will be described as an example.
In the figure, reference numeral 1 is an RFID tag unit, and 2 is a concrete rebar with the RFID tag unit 1 attached thereto.

  The RFID tag unit 1 includes a hollow housing 13 formed by fitting and joining a pair of rectangular parallelepiped box bodies 11 and 12 having an open upper portion, and a bottom surface 11a of the box body 11 standing vertically. A fixed pin (fixing tool) 14, an RFID tag 15 fixed to and suspended from the fixed pin 14, a reflector (conductive member) 16 provided on the bottom surface (inner surface) 12 a of the box 12, Positioning projections (positioning members) 17 (four in FIG. 1) for positioning and fixing the RFID tag 15 to the bottom surface 12a of the box 12 at a certain distance, and outside the bottom surface 12a of the box 12 It is comprised by the reinforcing bar fixture 18 provided in an outer surface and attaching to the reinforcing bar 2 of a concrete body.

  An air layer (first layer) 19 is formed between the upper surface of the RFID tag 15 and the upper surface of the housing 13, that is, the bottom surface 11 a of the box 11, and the lower surface of the RFID tag 15 An air layer (second layer) 20 is also formed between the lower surface in the housing 13, that is, the bottom surface 12 a of the box 12. As described above, since the air layers 19 and 20 made of a material having a relative dielectric constant of 8 or less are formed on both surfaces of the RFID tag 15, the attenuation of radio waves is reduced.

  Each size and size of the RFID tag unit 1 can be selected according to the material, type, and size of the product or structure on which the RFID tag unit is installed. The size of the RFID tag 15 and the size of the reflector 16 are accordingly selected. You can also choose.

The case 13 for use in a concrete product has a rectangular parallelepiped shape having a length of 17 to 25 mm, a width of 54 to 85 mm, and a height of 9 to 44 mm, for example, and the radio wave from the RFID tag 15 goes out of the housing 13. The material is not particularly limited as long as it is a material that can be used, but a material having a relative dielectric constant of 8 or less, such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, acrylic, polyurethane, ABS, polyethylene terephthalate, silicone, polybutylene, polyester, etc. It is preferable to be configured. Here, the box body 12 is fitted in the box body 11, and the contact portions of the box body 11 and the box body 12 are bonded and integrated with an adhesive or the like.
The housing 13 may have a configuration in which the openings of the pair of box bodies are bonded and integrated in addition to the configuration in which the pair of box bodies 11 and 12 are fitted and integrated.

  The fixing pin 14 is made of a material having a relative dielectric constant of 8 or less, for example, polyethylene, polypropylene, polystyrene, vinyl chloride, acrylic, polyurethane, ABS, polyethylene terephthalate, silicone, polybutylene, polyester, etc. It is preferable that it is bonded and fixed to the bottom 11a of the box 11 with an adhesive or the like. The distal end portion 14a of the fixing pin 14 has a truncated cone shape whose diameter increases toward the outside so that the suspended RFID tag 15 does not fall off.

  The RFID tag 15 is, for example, a card-like or sheet-like one having a length of 1 to 21 mm, a width of 26 to 80 mm, and a thickness of 3 mm or less, a device having a function of transmitting and receiving electromagnetic waves, and a passive RFID including an IC chip and an antenna unit. A tag is preferred.

Regarding electromagnetic waves to be used, there are infrared rays, visible rays, X-rays, etc. in addition to radio waves used in the information and communication field, but considering that radio waves transmitted from the RFID tag 15 pass through the concrete body and have a small attenuation. Then, the frequency of the radio wave that can be used for the RFID tag 15 is preferably 2.45 GHz or 5 GHz, and more preferably 2.45 GHz.
However, if the frequency band that can be used in the future is widened, the frequency can be used as appropriate.
The RFID tag 15 describes necessary information, for example, identification information such as information on the type of concrete used for the concrete body and manufacturing.

The reflector 16 preferably has a larger area than the RFID tag 15, and preferably has a larger area than the antenna portion of the RFID tag.
The reflector 16 is, for example, conductive having a length of 13 to 21 mm, preferably 17 to 21 mm, a width of 50 to 80 mm, preferably 70 to 80 mm, and a thickness of 0.01 mm or more, preferably 0.04 to 0.20 mm. The metal includes copper or an alloy thereof, aluminum or an alloy thereof, nickel or an alloy thereof, stainless steel, and the like. In particular, aluminum or an alloy thereof is preferable in consideration of workability and economy.
Even if the reflector 16 is provided outside the box 12 so as to be parallel to the RFID tag 15, the same effect can be obtained.

  In the present embodiment, positioning protrusions 17 are further provided. This positioning projection 17 is made of a material having a relative dielectric constant of 8 or less, for example, polyethylene, polypropylene, polystyrene, vinyl chloride, acrylic, polyurethane, ABS, polyethylene terephthalate, silicone, polybutylene, like the housing 13 and the fixing pin 14. It is preferably made of polyester or the like, and an L-shaped notch 17a that abuts on the side or end in the longitudinal direction of the RFID tag 15 is formed at the tip.

  The material for the reinforcing bar fitting 18 is not particularly limited as long as it has sufficient strength to be attached to the reinforcing bar. However, like the housing 13, the fixing pin 14 and the positioning protrusion 17, a material having a relative dielectric constant of 8 or less. For example, it may be made of polyethylene, polypropylene, polystyrene, vinyl chloride, acrylic, polyurethane, ABS, polyethylene terephthalate, silicone, polybutylene, polyester, etc., and the casing 13 side has a wide and substantially trapezoidal thickness and is elastic. A hole 22 for sandwiching and fixing the reinforcing bar 2 is formed in a substantially central portion of the plate-like body 21, and a slit 23 is formed on the housing 13 side of the hole 22. The hole 22 is formed with an opening 24 for inserting a reinforcing bar 2 that expands toward the tip.

In the RFID tag unit 1, the distance between the bottom surface 11a of the box 11 and the RFID tag 15 is preferably 2 mm or more, more preferably 2 to 8 mm, and further preferably 5 to 8 mm.
The distance between the upper surface of the reflector 16 and the RFID tag 15 is preferably 1 to 30 mm, more preferably 1 to 10 mm, and still more preferably 1 to 3 mm.

  Here, in order to reduce the attenuation of radio waves, the space between the bottom surface 11a of the box 11 and the RFID tag 15 and the space between the upper surface of the reflector 16 and the RFID tag 15 are filled with air as gas. It is good also as a structure filled with gas other than air. In addition, a material having a relative dielectric constant of 8 or less, for example, a resin having a relative dielectric constant of 8 or less, such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, acrylic, polyurethane, ABS, polyethylene terephthalate, silicone, polybutylene, polyester, etc. You may fill with. The relative dielectric constant of this material is more preferably 6 or less, and further preferably 5 or less.

  For example, the relative dielectric constant of polyethylene is 2.2 to 2.3, the relative dielectric constant of polystyrene is 2.3 to 3.4, and the relative dielectric constant of polyurethane is 5.0 to 5.3. Or you may satisfy | fill with the porous plastic which foamed said resin, such as foaming urethane and a polystyrene which is a substance whose dielectric constant is lower than these resin. Among these, urethane foam and polystyrene foam are more preferable because they contain a lot of air.

Further, the space between the bottom surface 11 a of the box 11 and the RFID tag 15 and the space between the upper surface of the reflector 16 and the RFID tag 15 may be filled with different materials.
Here, the relative permittivity in the present embodiment means a relative permittivity at a temperature of 20 ° C. and a frequency of 1 × 10 ⁶ to 1 × 10 ¹⁰ Hz, and is measured by a general measuring method such as a capacitance method. Can do.

  The RFID tag unit 1 is configured such that an RFID tag 15 is suspended in a housing 13 by a fixing pin 14, and the longitudinal side and end of the suspended RFID tag 15 are sandwiched by positioning protrusions 17. Since the reflector 16 is provided on the bottom surface 12a of the box 12 and fixed in the body 13, the attenuation of radio waves can be reduced, and thus the communicable distance is increased to, for example, 15 cm or more. Can take longer. Therefore, transmission / reception between the RFID tag unit 1 and an external device can be performed simply, accurately, reliably and efficiently.

  In order to attach the RFID tag unit 1 to the concrete reinforcing bar 2 to obtain a concrete product, first, the reinforcing bar 2 is arranged in the concrete formwork, and the opening 24 of the reinforcing bar attachment 18 of the RFID tag unit 1 is formed. Abutting on a desired position of the reinforcing bar 2, the reinforcing bar fitting 18 is pressed together with the RFID tag unit 1 toward the reinforcing bar 2. Thereby, the reinforcing bar 2 is fitted into the hole 22. The rebar fitting 18 is securely fixed to the rebar 2 because it sandwiches the rebar 2 by its own elastic force.

Next, concrete is placed in the concrete formwork and cured for a predetermined period. Then, if the concrete formwork is removed, a concrete product in which the target RFID tag unit 1 is embedded is obtained.
It is preferable to provide a sign or the like for notifying that the RFID tag unit 1 is embedded on the surface of the concrete product near the RFID tag unit 1 because the position of the RFID tag unit 1 can be easily specified. .

  The RFID tag unit 1 in this concrete product is provided with a first layer made of a material having a relative dielectric constant lower than that of concrete of 8 or less between the upper surface of the RFID tag and the upper surface in the housing. A second layer made of a material having a relative dielectric constant of 8 or less, which is lower than that of concrete, is provided between the lower surface of the RFID tag and the bottom surface of the housing, and the bottom surface of the housing or the lower side of the housing By using the configuration in which the reflector 16 is provided on the outer surface of the RFID tag unit, it is possible to reduce the attenuation of radio waves compared to using an RFID tag alone, and the RFID tag unit having a communicable depth of about 15 cm or more in this concrete product. 1 can be obtained.

In a normal concrete product, the distance from the surface of the concrete called “cover” to the reinforcing bar is about 5 cm, and a large concrete product or a civil engineering structure is generally about 10 cm.
Since the RFID tag is not affected by the reinforcing bar during communication, it is preferably installed between the reinforcing bar and the concrete surface. However, the RFID tag unit 1 according to the present embodiment has a very large thickness as the tag unit. In addition, the attenuation of radio waves can be reduced. Therefore, even if the RFID tag unit 1 is embedded between the covers, the strength and surface properties of the concrete are not affected. Further, when the RFID tag unit 1 is embedded, the RFID tag unit 1 may be installed so that the side on which the reflector 16 is provided faces the inside of the concrete product.

  The RFID tag unit 1 can be used for almost all concrete products, concrete structures, and concrete members in addition to the above-mentioned concrete products because the communicable distance is, for example, 15 cm or more, which is longer than before. Is possible.

Also, in this concrete product, information written on the RFID tag 15 of the RFID tag unit 1 by applying a reader / writer to the surface of the concrete body, for example, information on the type and production of concrete used in the concrete body Etc. can be read easily.
Further, in a concrete product having a cover thickness thinner than the communicable distance of the RFID tag unit 1, it is easy to find the fixed position of the RFID tag 15. That is, the radius of the detection area where the RFID tag 15 on the surface of the concrete product can be read can be increased.
Thereby, maintenance and management of a concrete product can be performed easily.

  According to the RFID tag unit 1 of the present embodiment, the attenuation of radio waves can be reduced, and therefore the communicable distance can be increased, for example, 15 cm or longer, which is longer than before. Therefore, transmission / reception between the RFID tag unit 1 and an external device can be performed simply, accurately, reliably and efficiently.

  Moreover, according to the concrete product of this embodiment, since the communicable distance can be made longer than conventional, for example, 15 cm or more, almost all the concrete products and concrete structures in addition to the above concrete products. It can be applied to concrete members.

“Second Embodiment”
FIG. 4 is a sectional view showing an RFID tag unit according to the second embodiment of the present invention.
The RFID tag unit 31 of this embodiment is different from the RFID tag unit 1 of the first embodiment in that, in the RFID tag unit 1 of the first embodiment, the fixing pin 14 on the bottom surface 11a of the box 11 of the housing 13 is used. , 14, the RFID tag 15 is suspended, and the RFID tag 15 is positioned and fixed to the bottom surface 12 a of the box body 12 using the positioning protrusions 17, and between the upper surface of the RFID tag 15 and the bottom surface 11 a of the box body 11. Is the air layer 19, and the space between the lower surface of the RFID tag 15 and the bottom surface 12a of the box 12 is also the air layer 20, whereas in the RFID tag unit 31 of the present embodiment, the upper surface of the RFID tag 15 A foamable resin layer (first layer) 32 made of a foamable material such as polystyrene foam is formed between the bottom surface 11a of the box 11 and the lower surface of the RFID tag 15 A foamable resin layer (second layer) 33 made of a foamable material such as polystyrene foam is also formed between the reflector 12 on the bottom surface 12a of the body 12 and the other constituent elements are the first. This is exactly the same as the RFID tag unit 1 of the embodiment.

The foamable resin layers 32 and 33 may be foamable resins having a large number of bubbles inside the resin, and the foamable resin layers 32 and 33 may be foamable resins having the same material composition. Alternatively, foamable resins having different material compositions may be used.
These foamable resin layers 32 and 33 are formed inside a resin such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, acrylic, polyurethane, ABS, polyethylene terephthalate, silicone, polybutylene, and polyester, which are substances having a relative dielectric constant of 8 or less. Since it has a large number of bubbles, it has a relative dielectric constant larger than that of the air layer, but is smaller than that of a concrete body or a solid (closely packed) resin.
The foamable material is not limited to a resin, and other foamable materials can be used as long as the relative dielectric constant is 8 or less.

  In the RFID tag unit 31, the reflector 16 is fixed to the bottom surface 12a of the box 12 which is a recess of the member, and a foamable resin layer 33 having a relative dielectric constant of 8 or less is formed on the reflector 16, and the foamable resin By fixing the RFID tag 15 on the layer 33 and forming the foamable resin layer 32 having a relative dielectric constant of 8 or less on the RFID tag 15, it can be easily obtained.

  Also in the RFID tag unit 31 of the present embodiment, similarly to the RFID tag unit 1 of the first embodiment, the attenuation of radio waves can be reduced, so that the communicable distance is, for example, 15 cm or more in the related art. You can take longer. Therefore, transmission / reception between the RFID tag unit 31 and the external device can be performed simply, accurately, reliably and efficiently.

“Third Embodiment”
FIG. 5 is a sectional view showing an RFID tag unit according to a third embodiment of the present invention.
The RFID tag unit 41 of this embodiment is different from the RFID tag unit 31 of the second embodiment in that the RFID tag unit 31 of the second embodiment has a reflector on the bottom surface of the RFID tag 15 and the bottom surface 12a of the box 12. 16, the foamable resin layer 33 made of a foamable material such as polystyrene foam is formed. On the other hand, in the RFID tag unit 41 of the present embodiment, the reflector on the lower surface of the RFID tag 15 and the bottom surface 12 a of the box 12 is used. The other components are the same as those of the RFID tag unit 31 of the second embodiment.

In the RFID tag unit 41, a foamable resin layer 32 made of a material having a relative dielectric constant of 8 or less is formed on the bottom surface 11a of the box 11 which is a recess of the member, and the RFID tag 15 is embedded in the foamable resin layer 32. It can be easily obtained by fixing and fixing the box body 12 with the reflector 16 fixed to the bottom surface 12a.
The RFID tag 15 may be fixed to the foamable resin layer 32 with an adhesive or the like.

FIG. 6 is a cross-sectional view showing a modified example of the RFID tag unit 41.
In the RFID tag unit 51, the foamable resin layer 32 is a columnar foamable resin layer 52 having a small cross-sectional area, and the foamable resin layer 52 has a smaller cross-sectional area than the foamable resin layer 32. Thus, the attenuation of radio waves can be further reduced.
The foamable resin layer 52 may be formed between the lower surface of the RFID tag 15 and the reflector 16 on the bottom surface 12a of the box 12 instead of the above. Moreover, you may form in multiple places.

In the RFID tag unit 41 of the present embodiment, similarly to the RFID tag unit 31 of the second embodiment, the attenuation of radio waves can be reduced, so that the communicable distance is, for example, 15 cm or more in the related art. You can take longer. Therefore, transmission / reception between the RFID tag unit 41 and the external device can be performed simply, accurately, reliably and efficiently.
Furthermore, if the foamable resin layer 32 is a columnar foamable resin layer 52 having a small cross-sectional area, attenuation of radio waves can be further reduced.

“Fourth Embodiment”
FIG. 7 is a sectional view showing an RFID tag unit according to the fourth embodiment of the present invention.
The RFID tag unit 61 of the present embodiment is different from the RFID tag unit 31 of the second embodiment in that, in the RFID tag unit 31 of the second embodiment, the upper surface of the RFID tag 15 and the bottom surface 11a of the box 11 are A foamable resin layer 32 made of a foamable material such as polystyrene foam is formed between them, and the foamable material such as polystyrene foam is also formed between the lower surface of the RFID tag 15 and the reflector 16 on the bottom surface 12a of the box 12. Whereas the foamable resin layer 33 is formed, in the RFID tag unit 61 of the present embodiment, a polyethylene having a relative dielectric constant of 8 or less between the upper surface of the RFID tag 15 and the bottom surface 11a of the box 11, Polypropylene, polystyrene, polyvinyl chloride, acrylic, polyurethane, ABS, polyethylene terephthalate, silicone, polyethylene A solid (closely packed) resin layer (first layer) 62 made of butylene, polyester or the like is formed, and the ratio between the lower surface of the RFID tag 15 and the reflector 16 on the bottom surface 12a of the box 12 is also high. Solid (densely packed) resin layer made of polyethylene, polypropylene, polystyrene, polyvinyl chloride, acrylic, polyurethane, ABS, polyethylene terephthalate, silicone, polybutylene, polyester, etc., which is a substance having a dielectric constant of 8 or less (second The other components are the same as those of the RFID tag unit 31 of the second embodiment.

The resin layers 62 and 63 may be resins having the same material composition as the resin layers 62 and 63, or may be resins having different material compositions.
These resin layers 62 and 63 are solid resin layers having no air bubbles inside such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, acrylic, polyurethane, ABS, polyethylene terephthalate, silicone, polybutylene, polyester, etc. Although the relative permittivity is larger than that of the layer, the attenuation of radio waves can be reduced.

  In the RFID tag unit 61, the reflector 16 is fixed to the bottom surface 12 a of the box 12 which is a concave portion of the member, and a resin layer 63 having a relative dielectric constant of 8 or less is formed on the reflector 16. It can be easily obtained by fixing the RFID tag 15 and forming the resin layer 62 having a relative dielectric constant of 8 or less on the RFID tag 15.

  Also in the RFID tag unit 61 of the present embodiment, similarly to the RFID tag unit 31 of the second embodiment, the attenuation of radio waves can be reduced, and thus the communicable distance is, for example, 15 cm or more in the related art. You can take longer. Therefore, transmission / reception between the RFID tag unit 61 and the external device can be performed simply, accurately, reliably and efficiently.

“Fifth Embodiment”
FIG. 8 is a sectional view showing an RFID tag unit according to the fifth embodiment of the present invention.
The RFID tag unit 71 of the present embodiment is different from the RFID tag unit 61 of the fourth embodiment in that in the RFID tag unit 61 of the fourth embodiment, the reflector on the bottom surface of the RFID tag 15 and the bottom surface 12a of the box 12 is used. A resin layer 63 made of polyethylene, polypropylene, polystyrene, polyvinyl chloride, acrylic, polyurethane, ABS, polyethylene terephthalate, silicone, polybutylene, polyester or the like, which is a material having a relative dielectric constant of 8 or less, was formed between On the other hand, in the RFID tag unit 71 of the present embodiment, an air layer 72 is formed between the lower surface of the RFID tag 15 and the reflector 16 of the bottom surface 12a of the box body 12, and the other components are as follows. This is exactly the same as the RFID tag unit 61 of the fourth embodiment.

In the RFID tag unit 71, a resin layer 62 having a relative dielectric constant of 8 or less is formed on the bottom surface 11a of the box 11 which is a recess of the member, and the RFID tag 15 is embedded and fixed in the resin layer 62. By fitting and fixing the box 12 with the reflector 16 fixed to 12a, it can be easily obtained.
The RFID tag 15 may be fixed to the resin layer 62 with an adhesive or the like.

FIG. 9 is a cross-sectional view showing a modified example of the RFID tag unit 71.
In the RFID tag unit 81, the resin layer 62 is a columnar resin layer 82 having a small cross-sectional area. Since the resin layer 82 has a smaller cross-sectional area than the resin layer 62, the attenuation of radio waves is further reduced. can do.
This resin layer 82 may be formed between the lower surface of the RFID tag 15 and the reflector 16 on the bottom surface 12a of the box 12 instead of the above. Moreover, you may form in multiple places.

In the RFID tag unit 71 of the present embodiment, similarly to the RFID tag unit 61 of the fourth embodiment, the attenuation of radio waves can be reduced, so that the communicable distance is, for example, 15 cm or more in the past. You can take longer. Therefore, transmission / reception between the RFID tag unit 71 and the external device can be performed simply, accurately, reliably and efficiently.
Furthermore, if the resin layer 62 is a columnar resin layer 82 having a small cross-sectional area, the attenuation of radio waves can be further reduced.

In the RFID tag unit 71 of the present embodiment, similarly to the RFID tag unit 61 of the fourth embodiment, the attenuation of radio waves can be reduced, so that the communicable distance is, for example, 15 cm or more in the past. You can take longer. Therefore, transmission / reception between the RFID tag unit 71 and the external device can be performed simply, accurately, reliably and efficiently.
Furthermore, if the resin layer 62 is a columnar resin layer 82 having a small cross-sectional area, the attenuation of radio waves can be further reduced.
In each of the above embodiments, the case where a gas, a foamable material, or a resin is used as the substance having a relative dielectric constant of 8 or less has been described. However, other substances having a relative dielectric constant of 8 or less, such as paraffin and glass Etc. can also be used.

It is a top view which shows the RFID tag unit of the 1st Embodiment of this invention. It is sectional drawing which follows the AA line of FIG. It is sectional drawing which follows the BB line of FIG. It is sectional drawing which shows the RFID tag unit of the 2nd Embodiment of this invention. It is sectional drawing which shows the RFID tag unit of the 3rd Embodiment of this invention. It is sectional drawing which shows the modification of the RFID tag unit of the 3rd Embodiment of this invention. It is sectional drawing which shows the RFID tag unit of the 4th Embodiment of this invention. It is sectional drawing which shows the RFID tag unit of the 5th Embodiment of this invention. It is sectional drawing which shows the modification of the RFID tag unit of the 5th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 RFID tag unit 2 Reinforcing bar 11 Box 11a Bottom surface 12 Box body 12a Bottom surface 13 Case 14 Fixing pin 14a Tip 15 RFID tag 16 Reflector 17 Positioning protrusion 17a Notch 18 Reinforcing bar fixture 19, 20 Air layer 21 Plate shape Body 22 Hole 23 Slit 24 Opening 31 RFID tag unit 32, 33 Foamable resin layer 41 RFID tag unit 42 Air layer 51 RFID tag unit 52 Foamable resin layer 61 RFID tag unit 62, 63 Resin layer 71 RFID tag unit 72 Air layer 81 RFID tag unit 82 Resin layer

Claims (8)

  An RFID tag is fixed in the housing, a conductive member is provided on the bottom surface of the housing or the outer surface on the lower side of the housing, and a relative permittivity is between the upper surface of the RFID tag and the upper surface of the housing. A first layer made of a material having a dielectric constant of 8 or less is provided, and a second layer made of a material having a relative dielectric constant of 8 or less is provided between the lower surface of the RFID tag and the bottom surface of the housing. RFID tag unit. The first layer comprises one or more selected from the group of gas, foamable material, and resin,
2. The RFID tag unit according to claim 1, wherein the second layer is made of one or more selected from the group of gas, foamable material, and resin, different from the first layer.   2. The RFID tag unit according to claim 1, wherein each of the first layer and the second layer is composed of one or more selected from the group of gas, foamable material, and resin.   The RFID tag unit according to claim 1, 2 or 3, wherein the RFID tag is fixed in the casing by suspending the RFID tag in the casing by a fixing tool.   The RFID tag unit according to any one of claims 1 to 4, wherein a fixture is provided outside the casing.   A concrete product comprising the RFID tag unit according to any one of claims 1 to 5.   A concrete structure comprising the RFID tag unit according to any one of claims 1 to 5. A method of fixing an RFID tag in a recess formed in a structure, product or member,
A conductive member is fixed or arranged on the bottom surface of the recess, and a second layer made of a material having a relative dielectric constant of 8 or less is formed on the conductive member, and the second layer or the second layer is formed on the second layer. The RFID tag is fixed or arranged so as to be embedded in a first layer, and a first layer made of a material having a relative dielectric constant of 8 or less is formed on the RFID tag.

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