WO2020241044A1 - Rf tag - Google Patents

Abstract

The present invention improves the communication characteristics of an inlay by means of an auxiliary antenna while protecting the inlay against physical/mechanical external forces, shocks, etc. This RF tag is provided with: an inlay 10 at least provided with an IC chip 11 and a loop circuit 11a electrically coupled with the IC chip 11; a first auxiliary antenna 20 disposed so as to overlap the IC chip 11 and the loop circuit 11a of the inlay 10; a second auxiliary antenna 30 disposed to the inlay 10 so as not to overlap at least the IC chip 11; and dielectric layers 40, 50 disposed so as to overlap the inlay 10 and the second auxiliary antenna 30, wherein the first auxiliary antenna 20 is disposed on the side of the dielectric layer 40 opposite to the disposing surface of the inlay 10 so as not to overlap at least a part of the second auxiliary antenna 30, and the inlay 10 and the first and second auxiliary antennas 20, 30 are electromagnetically coupled.

Description

RF tag

The present invention relates to an RF tag used by being attached to an arbitrary article or object such as a metal article, and particularly protects an inlay equipped with an IC chip from physical and mechanical external forces and impacts. Regarding RF tags that can be.

In general, a so-called RF tag incorporating an IC chip that readable and writably stores predetermined information about an arbitrary article or object is widely used.
RF tags are also called RFID (Radio Frequency Identification) tags, IC tags, non-contact tags, etc., and are so-called inlays in which an electronic circuit equipped with an IC chip and a wireless antenna is sealed and coated with a base material such as a resin film. The inlet) is an ultra-small communication terminal formed in the shape of a tag (tag), and a reader / writer wirelessly reads, writes, and reads / writes predetermined information on an IC chip inside the tag. (Read-only, write-once, read-write) can be performed.

Then, by writing predetermined information on such an RF tag and attaching it to an arbitrary article, object, etc., the information recorded on the RF tag is picked up by the reader / writer, and the information recorded on the tag is used for the article. It can be recognized, output, displayed, updated, etc. as predetermined information about.
Such an RF tag can record hundreds of bits to several kilobits of data in the memory of an IC chip, can record a sufficient amount of information as information about articles, etc., and is on the reading / writing device side. Since communication can be performed without contact, there is no concern about wear, scratches, dirt, etc. of the contacts, and since the tag itself can be turned off, it is possible to process it according to the object, and to make it smaller and thinner.

By using such an RF tag, various information about the article to which the tag is attached, for example, various information such as the name and identification symbol of the article, contents, components, manager, user, usage status, usage status, etc. can be obtained. It is possible to record and read and write a wide variety of information that was not possible with characters and barcodes printed on the label surface, simply by attaching a miniaturized and thinned tag to the article. It becomes.
Here, in such an RF tag, an RF tag in which an IC chip called a general-purpose inlay (inlet) and an antenna are simply film-coated is widely used. This type of inlay has become widespread in recent years because it is small and thin, can be easily attached to any object without taking up space, and can be immediately used as an RF tag.

However, since such a general-purpose inlay is simply a film-coated IC chip and antenna, if it is left as it is, it may cause a failure, malfunction, or damage due to an impact applied from the outside. For example, cargo pallets and containers are constantly subject to physical and mechanical external forces and impacts, and in the case of RF tags that are attached to such objects and used, in the state of inlays. There was a risk of failure or damage easily.
For this reason, for RF tags used in such an environment where external force is likely to be applied, by storing the general-purpose inlay in a predetermined cover, case, housing, etc., the inlay can be subjected to physical and mechanical impacts, etc. Protection is being done.

For example, Patent Document 1 proposes an RFID tag in which a general-purpose inlay is sandwiched between protective metal plates having a U-shaped cross section to protect it.
Further, Patent Document 2 proposes an RFID tag in which a general-purpose inlay sealed with a non-conductive material is embedded in a hollow slot of a metal holder.
By storing and sealing the general-purpose inlay in the protective plate and holder in this way, the inlay is protected from the surrounding environment, and the inlay is particularly affected by physical and mechanical external forces, impacts, collisions, etc. applied from the outside. It will be possible to easily protect it from failure or damage.

Japanese Unexamined Patent Publication No. 2011-204130 JP-A-2007-135183

However, in the techniques proposed in Patent Documents 1 and 2, no consideration has been given to the antenna provided in the general-purpose inlay.
A general-purpose inlay has an IC chip and an antenna portion including a loop circuit arranged near the periphery of the IC chip as a basic configuration, and the antenna portion is formed from a conductor extending in both the left and right directions of the IC chip (loop circuit). It constitutes a dipole antenna.
Such a dipole antenna is formed so as to be symmetrical on both sides of the IC chip so that the conductors constituting the antenna have a predetermined length, for example, a length of 1/2 wavelength.

Therefore, when the general-purpose inlay is used as it is, at least a space where the length of the dipole antenna can be arranged and stored is required.
In the techniques of Patent Documents 1 and 2, the dipole antenna as described above is not taken into consideration, and the entire inlay is housed in a metal protective plate or a holder.
For this reason, the dimensions of the metal protective plate and holder including the inlay must exceed the length of the dipole antenna of the inlay (for example, 1/2 wavelength), and the RF tag must be miniaturized and the degree of freedom in design, etc. It was a factor that hindered.

Further, in Patent Documents 1 and 2, there is no consideration about providing an auxiliary antenna for the general-purpose inlay.
When a general-purpose inlay is used as the RF tag, the radio communication distance of the general-purpose inlay can be lengthened or the frequency band can be widened by further stacking auxiliary antennas.
However, when such an inlay and an auxiliary antenna are stored as they are in a metal protective plate or holder as proposed in Patent Documents 1 and 2, the entire inlay and the auxiliary antenna are electrically operated by a metal case. There is a problem that the auxiliary antenna cannot function effectively because it is shielded / blocked.

As a result of diligent research, the applicant and the inventor of the present application have utilized the function of the auxiliary antenna to perform wireless communication of the inlay while effectively protecting the inlay from the surrounding environment without being restricted by the dimensions of the inlay antenna. We have come up with the invention of an RF tag that can be performed well.

That is, the present invention has been proposed in order to solve the problems of the conventional techniques as described above, and by arranging a metal auxiliary antenna that functions as a protective cover for the inlay on the inlay. RF that can improve the communication characteristics of the inlay by the auxiliary antenna while effectively protecting the inlay from physical and mechanical external forces and impacts without being restricted by the size and shape of the antenna provided in the inlay. Regarding tags.

In order to achieve the above object, the RF tag of the present invention is arranged so as to overlap the IC chip, the inlay including at least the loop circuit electrically coupled to the IC chip, and the IC chip and the loop circuit of the inlay. A first auxiliary antenna to be formed, a second auxiliary antenna arranged so as not to overlap the IC chip with respect to the inlay, and a dielectric layer arranged so as to overlap the inlay and the second auxiliary antenna. The first auxiliary antenna is arranged on the side of the dielectric layer opposite to the arrangement surface of the inlay so as not to overlap with at least a part of the inlay and / or the second auxiliary antenna. The inlay, the first auxiliary antenna, and the second auxiliary antenna are electromagnetically coupled to each other.

According to the present invention, by arranging a metal auxiliary antenna that functions as a protective cover for an inlay equipped with an IC chip and a loop circuit so as to overlap the inlay, it is restricted by the size and shape of the antenna provided in the inlay. The communication characteristics of the inlay can be improved by the auxiliary antenna while effectively protecting the inlay from physical and mechanical external forces and impacts.
Therefore, according to the present invention, the RF tag can be suitably used as an RF tag for an object to which a physical force or impact is often applied from the outside while ensuring the miniaturization of the RF tag and the degree of freedom in design. In particular, it is possible to effectively protect an IC chip whose function as an RF tag is difficult to recover when it is destroyed by a physical or mechanical external force or an impact.

It is an external perspective view which shows the RF tag which concerns on one Embodiment of this invention, (a) is the completed state of RF tag, (b) is an inlay which constitutes RF tag, 1st and 2nd auxiliary antenna, dielectric layer. Is shown in a disassembled state. (A) and (b) are plan views schematically showing the arrangement relationship of each component of the RF tag according to the embodiment of the present invention. (C) is a side view schematically showing the stacking relationship of each component of the RF tag according to the embodiment of the present invention. It is a line graph which shows the relationship between communication distance and frequency which shows the communication characteristic of the RF tag which concerns on one Embodiment of this invention. (A) to (d) show the communication characteristics of the RF tag according to the embodiment of the present invention, respectively, and the changes in the communication distance and the peak value of the frequency when the dimensions of the first and second auxiliary antennas are changed. It is a line graph showing (A) to (d) are plan views schematically showing an example in which the inlay of the RF tag and the plane arrangement positions of the first and second auxiliary antennas according to the embodiment of the present invention are different from each other. (A) to (d) are side views schematically showing an example in which the stacking arrangement position of each component of the RF tag according to the embodiment of the present invention is different. It is a top view which shows the example of the plane arrangement of the 2nd auxiliary antenna when the composition pattern of the antenna part of the inlay of the RF tag which concerns on one Embodiment of this invention is different, and (a) is the plane view which the antenna part of the inlay constitutes a dipole antenna. In this case, (b) is a case where the antenna portion of the inlay constitutes a monopole antenna, and (c) is a case where the antenna portion of the inlay is composed of only a loop circuit. (A) to (c) are plan views schematically showing other examples in which the inlay of the RF tag and the plane arrangement positions of the first and second auxiliary antennas according to the embodiment of the present invention are different from each other. ..

Hereinafter, embodiments of the RF tag according to the present invention will be described with reference to the drawings.
1A and 1B are external views showing an RF tag 1 according to an embodiment of the present invention, where FIG. 1A is a perspective view of the completed RF tag 1 and FIG. 1B is an inlay 10 constituting the RF tag 1. The perspective view of the 1 / 2nd auxiliary antennas 20 and 30, the dielectric layer 40, and the dielectric layer 50 (the second dielectric layer) is shown.
2 (a) and 2 (b) are plan views schematically showing the arrangement relationship between the inlay 10 and the 1st and 2nd auxiliary antennas 20 and 30, and FIG. 2 (c) shows each configuration of the RF tag 1. It is a side view which shows typically the stacking relation of an element.

As shown in these figures, the RF tag 1 according to the present embodiment includes an inlay 10 constituting an RF tag for wireless communication, first and second auxiliary antennas 20 and 30, and dielectric layers 40 and 50. It is an RF tag having a structure in which each component composed of the above is arranged vertically.
Then, the first auxiliary antenna 20 arranged on the uppermost surface in the stacking direction of the RF tag 1 functions as a protective cover (top cover) for protecting the inlay 10 arranged inside the tag from the external environment. There is.
Further, the second auxiliary antenna 30 arranged so as to overlap the inlay 10 functions as an antenna of the inlay 10 together with the first auxiliary antenna 20, so that the inlay 10 is covered with the first and second auxiliary antennas 20 and 30. Even so, good wireless communication characteristics can be obtained without impairing the communication function.

In particular, in the present embodiment, the first top cover (protective cover) of the RF tag 1 is laminated and arranged on one surface (upper surface) of the dielectric layers 40 and 50 on which the inlay 10 is placed and fixed. By forming the auxiliary antenna 20 with a metal member (metal plate), the durability, impact resistance, pressure resistance, etc. against physical forces such as impacts and pressures applied to the RF tag 1 from the outside are improved, and external forces and pressures are improved. It is possible to effectively prevent the inlay 10 arranged inside from being damaged or damaged due to an impact.
Further, the first auxiliary antenna 20 that functions as a protective cover for such an RF tag 1 is arranged so as not to overlap with at least a part of the inlay 10 and / or the second auxiliary antenna 30, and the second auxiliary antenna 30 is arranged. Is arranged so as not to overlap the IC chip 11 with respect to the inlay 10, so that the first and second auxiliary antennas 20 and 30 function as antennas of the inlay 10, and the communication characteristics of the RF tag 1 are improved. It can be maintained and improved in a state.

Specifically, as shown in FIGS. 1 and 2, the RF tag 1 according to the present embodiment is on the same plane as the inlay 10 having the IC chip 11 and the antenna portion 12 in an insulated state with respect to the inlay 10. The planar first and second auxiliary antennas 20 and 30 arranged in the above, and the inlay 10 and the first and second auxiliary antennas 20 and 30 serve as a base material layer on which the inlay 10 and the first and second auxiliary antennas 20 and 30 are arranged and mounted. It is configured to include dielectric layers 40 and 50 that function as a dielectric constant adjusting layer for the antenna.
The 1st and 2nd auxiliary antennas 20 and 30 are formed in a predetermined shape and size corresponding to the communication frequency of the inlay 10, respectively, and the 1st and 2nd auxiliary antennas 20 and 30 are formed. Are arranged at predetermined positions with respect to the inlay 10 (see FIGS. 2A to 2C), and are mounted on the dielectric layers 40 and 50.
Each part will be described in detail below.

[Inlay]
The inlay 10 constitutes an RF tag that wirelessly reads, writes, and reads / writes predetermined information from a reader / writer (read / write device) (not shown). For example, a read-only type or a write-once type. , Read-write type, etc.
Specifically, the inlay 10 has an IC chip 11 and an antenna portion 12 electrically conducted and connected to the IC chip 11, and the IC chip 11 and the antenna portion 12 serve as a base material, for example, PET. After being mounted and formed on one sealing film 13 made of resin or the like, another sealing film 13 is overlapped and sealed in a state of being sandwiched between the two sealing films 13.・ It is protected.
In the example shown in FIG. 1, an antenna portion 12 composed of an IC chip 11 and dipole antennas extending on both left and right sides in the tag longitudinal direction of the IC chip 11 is sandwiched and sealed with a rectangular sealing film 13. It is 10.

The IC chip 11 is made of a semiconductor chip such as a memory, and can record data of, for example, several hundred bits to several kilobits.
An antenna portion 12 composed of a conductor pattern is connected to both the left and right sides of the IC chip 11, and a part of the antenna portion 12 is a loop circuit composed of a loop-shaped circuit conductor so as to surround the periphery of the IC chip 11. It is formed as a loop portion) 11a. The antenna portions 12 constituting the dipole antenna are connected to the left and right sides of the IC chip 11 via the loop circuit 11a.

Then, read / write (data call / registration / deletion / update, etc.) by wireless communication between the IC chip 11 and a reader / writer (not shown) via the antenna unit 12 and the 1st / 2nd auxiliary antennas 20 and 30 described later. ) Is performed, and the data recorded on the IC chip 11 is recognized.
As the data recorded on the IC chip 11, for example, arbitrary data such as a product identification code, name, weight, content, manufacturer / seller name, manufacturing location, manufacturing date, expiration date, etc. can be recorded. Yes, and rewriting is also possible.

The antenna portion 12 including the loop circuit 11a has a predetermined shape by etching a metal thin film such as a conductive ink or a conductive aluminum vapor-deposited film on the surface of one sealing film 13 as a base material. It is formed by molding to a size (length, area).
Here, in the antenna portion 12, the length of the dipole antenna portion extending on both the left and right sides of the IC chip 11 is one integral of the wavelength of the radio wave frequency of the inlay 10, for example, approximately 1/2 or approximately 1 of the wavelength of the radio wave frequency. It is formed to have a length of / 4.
In the inlay 10 shown in FIGS. 1 and 2, the antenna portion 12 is bent twice in the longitudinal direction extending to the left and right sides of the IC chip 11 at a substantially right angle, so that both ends of the antenna portion 12 in the longitudinal direction loop with each other. It is formed in a hook shape extending toward the circuit 11a, and is formed so as to have a predetermined antenna length.

Further, in the antenna portion 12 according to the present embodiment, the central portion of the metal thin film is formed in a hollow / punched shape in which the metal thin film does not exist along the longitudinal direction from the vicinity of the IC chip 11 to both end portions in the longitudinal direction. The conductive portion of the antenna portion 12 is formed so as to have an annular shape or a loop shape.
The antenna portion 12 provided in the inlay 10 is not limited to the dipole antenna extending on both the left and right sides of the IC chip 11, but as will be described later (see FIGS. 7 and 8), only on one of the left and right sides of the IC chip 11. It can also be configured as an extendable monopole antenna.
Further, it can be configured as an antenna consisting only of the loop circuit 11a without a dipole antenna or a monopole antenna (see FIGS. 7 and 8).

The sealing film 13 is made of a flexible film material such as polyethylene, polyethylene terephthalate (PET), polypropylene, polyimide, polyvinyl chloride (PVC), and acrylonitrile-butadiene-styrene copolymer synthetic resin (ABS). It is preferable that the IC chip 11 and the antenna portion 12 to be sealed are made of a transparent PET resin or the like that can be visually recognized from the outside.
Further, the film surface on one side of the sealing film 13 may be provided with an adhesive layer / adhesive layer so that it can be attached to a base material or an article.
The sealing film 13 may be sealed with the IC chip 11 and the antenna portion 12 sandwiched between the two sealing films 13, or the sealing film 13 may be bent to form an IC. The antenna portion 12 including the chip 11 and the loop circuit 11a can be sandwiched and sealed.

As the communication frequency band used in the inlay 10, the RF tag 1 of the present embodiment targets the 920 MHz band (915-930 MHz: 15 MHz width) belonging to the so-called UHF band.
The frequency band generally used in the RF tag includes, for example, several types of frequency bands such as a band of 135 kHz or less, a 13.56 MHz band, an 860 M to 960 MHz band belonging to the UHF band, and a 2.45 GHz band. The communication distance at which wireless communication is possible differs depending on the frequency band used, and the optimum antenna length and wiring pattern also differ depending on the frequency band.

In Japan, due to the revision of the Radio Law, RF tags will be shifted from the previously used 950 MHz band (950-958 MHz: 8 MHz width) to the 920 MHz band (915-930 MHz: 15 MHz width). , The available frequency bands have been expanded.
Therefore, in the present embodiment, since the inlay 10 can be miniaturized and the first and second auxiliary antennas 20 and 30 described later are formed to a predetermined size, the UHF band having a short wavelength and the antenna can be miniaturized is targeted. Specifically, the 920 MHz band is targeted, and good communication characteristics can be obtained in this 920 MHz band.
However, if there are no restrictions on the sizes of the inlay 10 and the 1st and 2nd auxiliary antennas 20 and 30, the technical idea itself according to the present invention can of course be applied to frequency bands other than the 920 MHz band and the UHF band. ..

[1st auxiliary antenna]
The first auxiliary antenna 20 is a planar member that is laminated and arranged on the uppermost surface of the RF tag 1 on one surface side, and is formed of a predetermined metal material (metal plate).
By providing such a first auxiliary antenna 20 made of metal, one surface (upper surface) side of the RF tag 1 is protected by a metal plate, and the durability, impact resistance, weather resistance, and heat resistance of the RF tag 1 are provided. The properties and waterproofness will be improved.
Further, the first auxiliary antenna 20 made of metal can function as an antenna of the inlay 10 arranged inside the RF tag 1, and can maintain and improve the communication characteristics of the RF tag 1 in a good state. Will be.

Specifically, as shown in FIG. 1, the first auxiliary antenna 20 is made of a plate-shaped member made of a metal material, and the plate-shaped member is not formed with a notch or an opening, and has a rectangular shape on all sides. It is composed of a metal plate.
By arranging the rectangular first auxiliary antenna 20 in which the notch or the opening is not formed so as to overlap the IC chip and the loop circuit in this way, the physical and mechanical through the notch and the opening can be achieved. It is possible to prevent an external force or an impact, and it is possible to effectively protect an IC chip or the like whose function as an RF tag is difficult to recover when it is destroyed by such an external force or an impact.

Further, as shown in FIGS. 2A to 2C, the first auxiliary antenna 20 has a longitudinal dimension larger than that of the dielectric layers 40 and 50 which are the base materials of the inlay 10 and the second auxiliary antenna 30. It is formed to be short.
As a result, the first auxiliary antenna 20 is laminated on the dielectric layers 40 and 50 so as not to overlap with at least a part of the inlay 10 and the second auxiliary antenna 30 laminated on the dielectric layers 40 and 50. Can be done.
As a result, even if the first auxiliary antenna 20 made of metal is arranged on the uppermost layer of the RF tag 1, at least a part of the inlay 10 and the second auxiliary antenna 30 is not covered by the first auxiliary antenna 20. That is, the first auxiliary antenna 20 made of metal can be exposed so that it does not exist above (see FIG. 2A), and the antenna portion 12 of the inlay 10 and the second auxiliary antenna 30 can be attached to the antenna of the RF tag 1. It will be possible to function effectively as.

In addition, in FIG. 2A, in order to facilitate understanding, the second auxiliary antenna 30 exposed from the outer edge of the first auxiliary antenna 20 is shown so as to be directly visible, but in the actual RF tag 1, it is shown. Since the dielectric layer 40 is laminated on the upper surface of the inlay 10 and the second auxiliary antenna 30 (see FIG. 2B), it cannot be directly viewed from the outside.
Therefore, “exposed” in the present specification means that the inlay 10 and the second auxiliary antenna 30 are exposed from the end and the outer edge of the first auxiliary antenna 20, and are exposed on the surface of the RF tag 1. It does not mean to do.

Then, by arranging and fixing the first auxiliary antenna 20 on the surface (top surface) of the RF tag 1, the first auxiliary antenna 20, the inlay 10 and the second auxiliary antenna 30 arranged inside the RF tag 1 are arranged. And are stacked and arranged at predetermined positions.
With such a laminated arrangement configuration, the first auxiliary antenna 20 and the IC chip 11 of the inlay 10 are arranged so as to face each other via the dielectric layer 40 and the second auxiliary antenna 30 as shown in FIG. 2C. As a result, the first auxiliary antenna 20 is electromagnetically connected and coupled by a so-called capacitor coupling, and the first auxiliary antenna 20 functions as an antenna (auxiliary antenna) of the inlay 10.

Specifically, the first auxiliary antenna 20 functions together with the antenna unit 12 provided in the inlay 10, or instead of the antenna unit 12, as an antenna for improving and adjusting the communication characteristics of the inlay 10. It is composed of planar conductive members that are laminated and arranged on one side (upper surface side) of the inlay 10, and the inlay 10 is insulated by a sealing film 13 and a dielectric layer 40 that seal the inlay 10 with a resin. Is placed.
That is, in the first auxiliary antenna 20 made of a conductive member such as metal, the inlay 10 is entirely resin-sealed by the sealing film 13, and a dielectric layer is formed between the inlay 10 and the first auxiliary antenna 20. Since 40 is laminated, it is physically insulated from the inlay 10.

Then, by stacking and arranging such a first auxiliary antenna 20 on one side of the inlay 10, the first auxiliary antenna 20 and the IC chip 11 of the inlay 10 are interposed via the sealing film 13 and the dielectric layer 40. The antennas are arranged so as to face each other, and an electromagnetic connection is made by so-called capacitor coupling.
As a result, the first auxiliary antenna 20 is laminated on the inlay 10 in the vertical direction (height direction), so that the first auxiliary antenna 20 is stacked together with the antenna portion 12 including the loop circuit 11a of the inlay 10 or in place of the antenna portion 12. A two-dimensional antenna is configured by the auxiliary antenna 20, and the first auxiliary antenna 20 functions as a booster for communication radio waves, so that the communication characteristics of the inlay 10 can be adjusted and improved.

Here, as shown in FIG. 2A, the length of the first auxiliary antenna 20 in the longitudinal direction is approximately ½ of the wavelength of the radio wave frequency of the inlay 10 (half wavelength). It is preferably formed.
Then, the overall size (length) of the RF tag 1 is substantially defined by the length of the first auxiliary antenna 20.

Therefore, if the length of the first auxiliary antenna 20 is set to 1/2 wavelength, the overall size (length) of the RF tag 1 is also approximately 1/2 wavelength (half wavelength) while ensuring good communication characteristics. It can fit in a slightly larger (longer) size.
When reducing the overall length of the RF tag 1, for example, as the size of the first auxiliary antenna 20, the total length of the two adjacent short and long sides is the radio frequency of the inlay 10. It can also be formed so as to have a length of, for example, approximately 1/2 of the wavelength.

With such a configuration, the first auxiliary antenna 20 can obtain good communication characteristics as an antenna having a length of approximately 1/2 of the wavelength of the radio wave frequency of the inlay 10.
Specifically, for example, in the case of the communication frequency of the target inlay 10 of 920 MHz, λ≈326.0 mm and λ / 2≈163.0 mm. Therefore, the first auxiliary antenna 20 is formed so that the length of the long side or the total length of the two sides including the long side and the short side is about 163.0 mm.

As described above, the inlay 10 has an IC chip 11 and an antenna portion 12 electrically conducted and connected to the IC chip 11, and the IC chip 11 and the antenna portion 12 serve as a base material, for example. After being mounted and formed on one sealing film 13 made of PET resin or the like, another sealing film 13 is overlapped and sealed while being sandwiched between the two sealing films 13. It is configured to be stopped and protected.
Further, a dielectric layer 40 is interposed between the inlay 10 and the first auxiliary antenna 20, and a dielectric 50 is interposed on the mounting surface side.
Therefore, in the inlay 10 according to the present embodiment, the wavelength shortening effect is generated by the structure in which the PET layer and the dielectric layer are interposed between the first auxiliary antenna 20 which is a conductor and the antenna portion 12 of the inlay 10, and the apparent wavelength is increased. May be shortened. These relative permittivity is about "2-4". Since the wavelength shortening rate is √ (relative permittivity), it is about √ (2 to 4).
Therefore, the length of the long side of the first auxiliary antenna 20 or the lengths of the two sides of the long side and the short side are also approximate values, and the length is, for example, approximately λ / 2. Is sufficient, and the length may vary depending on changes in communication characteristics depending on the material and dielectric constant of the dielectric layers 40 and 50 of the RF tag 1, the usage environment of the tag, the usage mode, and the like.

As described above, by making the first auxiliary antenna 20 that covers the surface of the RF tag 1 made of metal, the first metal is made of metal against mechanical and physical external forces and impacts applied to the RF tag 1. The strength, durability, and impact resistance of the auxiliary antenna 20 can protect the inside of the housing, and effectively prevent the inlay 10 housed in the RF tag 1 from being damaged or broken. it can.
Then, by providing the first auxiliary antenna 20 made of metal, the first auxiliary antenna 20 can function as an antenna of the inlay 10 of the RF tag 1, and the RF tag 1 even if the inlay 10 does not have the dipole antenna. You will be able to perform wireless communication.

Here, as the metal material constituting the first auxiliary antenna 20, for example, steel, copper, stainless steel, aluminum alloy, zinc alloy, or the like can be used.
The fact that the RF tag 1 is made of metal provides durability and impact resistance against mechanical and physical external forces applied to the surface of the RF tag 1, and is a metal member arranged on the surface of the RF tag 1. This is to form an auxiliary antenna of the inlay 10.
Therefore, in order to achieve such an object, if the first auxiliary antenna 20 arranged on the front surface side (upper surface side) of the RF tag 1 is made of metal, the back surface side (bottom surface side) of the RF tag 1 is It may be made of metal or non-metal (for example, made of synthetic resin) (see FIG. 6 described later). For example, a metal plate member is also formed on the surface of the dielectric layer 50 on the back surface side of the RF tag 1. Etc. can also be arranged.

[Second auxiliary antenna]
The second auxiliary antenna 30 functions as an extra antenna for improving and adjusting the communication characteristics of the inlay 10 described above, and is mounted on the dielectric layers 40 and 50 as shown in FIGS. 1 and 2. It is composed of a planar conductive member arranged on the same plane as the inlay 10, and is insulated from the resin-sealed inlay 10 by the sealing film 13. That is, the inlay 10 is entirely resin-sealed by the sealing film 13, and is physically insulated from the second auxiliary antenna 30 made of a conductive member.
By arranging the second auxiliary antenna 30 in the vicinity of the inlay 10, the second auxiliary antenna 30 and the IC chip 11 of the inlay 10 are arranged so as to face each other via the sealing film 13. Electromagnetic connection is made by the capacitor coupling.

Then, as shown in FIGS. 2B and 2C, the second auxiliary antenna 30 is arranged so as not to overlap the IC chip 11 of the inlay 10 with respect to the inlay 10, and such an inlay is used. The 10 and / or at least a part of the second auxiliary antenna 30 is arranged so as not to overlap with the first auxiliary antenna 20.
In the example shown in the figure, the second auxiliary antenna 30 is arranged so as to overlap only the antenna portion 12 on the right side of the inlay 10 along the longitudinal direction of the inlay 10, and does not overlap the IC chip and the antenna portion 12 on the left side. (See FIG. 2B).
Further, with respect to such an inlay 10 and a second auxiliary antenna 30, the first auxiliary antenna 20 is arranged so as to overlap the entire inlay 10 and the left side portion of the second auxiliary antenna 30 along the longitudinal direction. As a result, the first auxiliary antenna 20 does not overlap the right end of the second auxiliary antenna 30, and a part of the second auxiliary antenna 30 is exposed, for example, about 10 to 20 mm (FIG. 2 (FIG. 2). a) See).
In addition, in FIG. 2A, in order to facilitate understanding, the second auxiliary antenna 30 exposed from the outer edge of the first auxiliary antenna 20 is shown so as to be directly visible, but in the actual RF tag 1, it is shown. Since the dielectric layer 40 is laminated on the upper surface of the second auxiliary antenna 30, it cannot be directly viewed from the outside.

In this way, the second auxiliary antenna 30 is arranged on the inlay 10 so as to face each other on the same plane and does not overlap the IC chip 11 of the inlay 10, and further, the second auxiliary antenna 30 (or By arranging a part of the inlay 10) so as not to overlap the first auxiliary antenna 20 and to be exposed, the second auxiliary antenna 30 can be effectively functioned as an antenna of the inlay 10 together with the first auxiliary antenna 20. You will be able to
That is, a two-dimensional antenna is formed by the antenna portion 12 of the inlay 10 and the first / second auxiliary antennas 20 and 30, and the second auxiliary antenna 30 functions as a booster of communication radio waves together with the first auxiliary antenna 20. , The communication characteristics of the inlay 10 will be adjusted and improved.

Here, the second auxiliary antenna 30 is formed by etching or punching a metal thin film such as a conductive ink or a conductive aluminum vapor-deposited film formed on the surface of a film as a base material such as PET resin. It can be formed by molding into a predetermined shape and size (length, area).
In the present embodiment, as shown in FIGS. 2A to 2C, the second auxiliary antenna 30 has a rectangular surface having long and short sides substantially the same length as the long and short sides of the inlay 10. It is designed to be formed in a shape.
Further, both the long side and the short side of the second auxiliary antenna 30 are shorter than the long side and the short side of the dielectric layers 40 and 50 so as not to protrude from the dielectric layers 40 and 50 which are the base materials. As shown in FIGS. 2A and 2B, the surfaces of the dielectric layers 40 and 50 are arranged so that the second auxiliary antenna 30 does not overlap the IC chip 11 of the inlay 10. It is designed to fit in.

When the second auxiliary antenna 30 is arranged so as to overlap the loop circuit 11a of the inlay 10, particularly the IC chip 11, the communication characteristics of the IC chip 11 may be impaired by the conductive member forming the second auxiliary antenna 30.
That is, a loop circuit 11a is formed in the vicinity of the IC chip 11 of the inlay 10, and the loop circuit 11a is provided for the purpose of matching impedances and for communicating with a magnetic field component. It is necessary to prevent this magnetic field component from being obstructed by the conductor of the second auxiliary antenna 30.
On the other hand, if the second auxiliary antenna 30 and the inlay 10 are too far apart, the electrical connection by the so-called capacitor coupling via the sealing film 13 becomes insufficient, and good communication characteristics cannot be obtained. ..

Therefore, in the present embodiment, the second auxiliary antenna 30 is arranged so as not to overlap the IC chip 11 of the inlay 10 at least.
Further, the second auxiliary antenna 30 overlaps a portion of the inlay 10 excluding the IC chip 11, that is, a part of the antenna portion 12 including the loop circuit 11a via a sealing film 13 that covers the entire inlay 10. The second auxiliary antenna 30 and the IC chip 11 of the inlay 10 are arranged to face each other via the sealing film 13, and are electromagnetically connected by a capacitor coupling.
With such an arrangement configuration, the second auxiliary antenna 30 can secure a wide antenna area together with the antenna portion 12 of the inlay 10 without disturbing the communication function of the inlay 10, thereby maximizing the antenna gain. It will be possible to increase.

The current flowing through the second auxiliary antenna 30 when data is read or written to the inlay 10 flows only through the peripheral portion of the planar second auxiliary antenna 30 (skin effect).
Therefore, if the second auxiliary antenna 30 has the above-mentioned size and shape, the planar portion can be formed in, for example, a mesh shape, a grid shape, or the like.
By forming the second auxiliary antenna 30 in a mesh shape or the like in this way, the function as an antenna is not impaired by the skin effect, and the area of the entire conductor portion of the second auxiliary antenna 30 can be reduced. Conductive materials such as conductive ink forming the second auxiliary antenna 30 can be reduced, and the cost of the RF tag 1 can be further reduced.

[Dielectric layer]
The dielectric layers 40 and 50 are members that serve as a base material layer on which the above-mentioned inlay 10 and the second auxiliary antenna 30 are mounted and also function as a dielectric constant adjusting layer for the mounted inlay 10. In this embodiment, two dielectric layers 40 and 50 having the same shape and the same size are provided.
Specifically, the dielectric layers 40 and 50 are at least IC chips with respect to the above-mentioned inlay 10 and inlay 10 so that the inlay 10 and the second auxiliary antenna 30 can be arranged and mounted on the same plane without protruding. The second auxiliary antenna 30 is arranged so as not to overlap with the eleven, and is formed in a plate shape, a plane shape, or the like having the same shape and the same size, which is one size larger than the outer shape (see FIG. 2). The size of the outer shape of the RF tag 1 is defined by the dielectric layers 40 and 50 (see FIGS. 1 and 2).

The two such dielectric layers 40 and 50 first have an inlay 10 and a second auxiliary on one surface side (upper surface side in FIG. 1) of the dielectric layer 50 on the lower layer side (bottom surface side) of the RF tag 1. The antennas 30 are stacked and arranged on the same plane. At this time, the second auxiliary antenna 30 is arranged so as not to overlap at least the IC chip 11 of the inlay 10.
Then, the first auxiliary antenna 20 on the upper layer side (upper surface side) of the RF tag 1 is superposed on one surface (upper surface) of the dielectric layer 40 on which the inlay 10 and the second auxiliary antenna 30 are mounted, and the inlay is used as a cover member. 10. Stacked and fixed so as to cover the upper surface of the second auxiliary antenna 30.

As a result, the inlay 10 and the second auxiliary antenna 30 are sealed in a state of being sandwiched by the two dielectric layers 40 and 50, and are protected from the outside.
As described above, in the present embodiment, the two dielectric layers 40 and 50 are formed in the shape of a case (housing) that covers the entire laminated inlay 10 and the second auxiliary antenna 30. By protecting the inlay 10 and the second auxiliary antenna 30 by the shape-shaped dielectric layers 40 and 50, the weather resistance, heat resistance, and waterproofness of the RF tag 1 can be enhanced.

The dielectric layers 40 and 50 configured as such a case (housing) are inseparably fixed and fixed by, for example, a fitting structure (not shown), or by ultrasonic welding or an adhesive.
Further, the inlay 10 and the second auxiliary antenna 30 arranged between the dielectric layers 40 and 50 and the first auxiliary antenna 20 arranged on the surface of the dielectric layer 40 also have a fitting structure and an adhesive. It is fixed and fixed from the dielectric layers 40 and 50 so as not to fall off.
Further, among the dielectric layers 40 and 50, the dielectric layer 50 on the bottom surface side of the RF tag 1 is not particularly shown, but for example, an adhesive material made of double-sided tape (adhesive tape) or the like, a plate-shaped magnet, or the like. Is provided, and it can be attached and attached to the surface of a metal article to be attached by the adhesive force of the adhesive material and the magnetic force of the magnet.
As a result, the RF tag 1 is arranged and fixed to the surface of the metal article so that the dielectric layer 50 is attached and fixed to the surface to be attached and is not easily dropped or peeled off.

Here, the dielectric layers 40 and 50 according to the present embodiment as described above include, for example, a polycarbonate resin, an acrylonitrile-butadiene-styrene copolymer (AES) resin, a polypropylene resin, a polyethylene resin, a polystyrene resin, and an acrylic resin. , Polypropylene resin, Polyferrenin sulfide resin, Acrylonitrile-butadiene-styrene copolymer (ABS) resin, Polyvinyl chloride resin, Polyurethane resin, Fluororesin, Silicone resin and other thermoplastic resins, Thermoplastic elastomer and other resin materials, or It can be formed from a crosslinked polyolefin foam such as foamed polyethylene, acrylic foam, and foamed polypropylene.
Further, each of the dielectric layers 40 and 50 can be formed of a single strip-shaped member formed of the resin material or the crosslinked polyolefin foam as described above, and a plurality of (for example, two layers) strip-shaped members can be formed. It is also possible to superimpose one dielectric layer 40 or a dielectric layer 50 to form one.

Further, the dielectric layers 40 and 50 as described above are formed so as to have a predetermined relative permittivity for adjusting the communication characteristics of the inlays 10 stacked and arranged together with the second auxiliary antenna 30. It can function as a dielectric constant adjusting layer for the inlay 10 on which 40 and 50 are mounted and laminated as a base material.
For example, the dielectric layers 40 and 50 can be formed as a dielectric constant adjusting layer having a relative permittivity suitable for specifying communication of the inlay 10 by being formed by a predetermined member with a predetermined thickness. ..

Since the dielectric layers 40 and 50 have a predetermined relative permittivity and thickness in this way, the influence from the metal to which the RF tag 1 is attached can be avoided and absorbed by the dielectric layers 40 and 50. As a communication characteristic of the RF tag 1, a good communication distance as described later can be obtained (see FIG. 3).
Therefore, appropriate materials and thicknesses are selected for the dielectric layers 40 and 50 in consideration of various conditions such as the type and communication characteristics of the inlay 10 to be used, the article in which the RF tag 1 is used, the environment in which it is used, and the frequency band in which it is used. By selecting and exchanging only the dielectric layer 40, it is possible to use the RF tag 1 for different articles or to correspond to different communication frequencies.

[Communication characteristics]
Next, the communication characteristics of the RF tag 1 according to the present embodiment having the above configuration will be described with reference to FIGS. 3 and 4.
3 to 4 are line graphs showing the relationship between the communication distance and the frequency, showing the communication characteristics of the RF tag 1 according to the embodiment of the present invention.
A known evaluation method / evaluation system can be used for the evaluation of the communication characteristics of the RF tag 1, and the evaluation of the present embodiment shown below is carried out using the Tagformance system of Voyantic Co., Ltd. as the evaluation system.
In addition, the evaluation was performed not by directly measuring the communication distance, but by a value converted from the radio field strength when the communication distance was kept at a certain distance.
The measurement was performed by attaching the RF tag 1 to a stainless steel plate (150 * 100 * t2 mm).

The graph shown in FIG. 3 contains the RF tag 1 according to the present embodiment and the inlay having a monopole antenna proposed in the prior application (Japanese Patent Application No. 2018-138196) according to the applicant of the present application. Contrast with an RF tag (Comparative Example 1) in which an auxiliary antenna having a notch formed on the surface of the housing is provided and the IC chip and loop circuit of the inlay are arranged directly under the notch in the housing. This is the case.
In the figure, the solid line is the RF tag according to Comparative Example 1, the broken line is the case where the inlay of Comparative Example 1 is moved from directly below the notch to directly below the auxiliary antenna (Comparative Example 2), and the alternate long and short dash line is the main line. This is the case of the RF tag 1 according to the embodiment.

As shown in these graphs, first, it can be seen that the RF tag of Comparative Example 1 has a long communication distance in the high frequency band, particularly in the 860 to 940 MHz band.
On the other hand, in the case of the RF tag of Comparative Example 2, the band in which wireless communication is possible is extremely narrow, and the communication distance is also very short (3 m or less), which makes it unusable for practical use. I understand. This is because the communication function of the inlay is hindered by the auxiliary antenna arranged on the surface of the housing.

On the other hand, in the RF tag 1 according to the present embodiment, the communicable frequency band is slightly narrower than that in Comparative Example 1, but it can be seen that the same long communication distance as in Comparative Example 1 is obtained. ..
In particular, in the 920 to 940 MHz band, a communication distance of 10 m or more is obtained, and in the 920 MHz band, a peak (about 13 m) of the communication distance is obtained.

The graphs shown in FIGS. 4A to 4D show the communication characteristics when the dimensions and the like of the auxiliary antenna are changed in the present embodiment.
The graph shown in FIG. 4A shows a case where the total length (longitudinal direction) of the first auxiliary antenna 20 is changed. As the total length of the first auxiliary antenna 20 is shortened, the peak of the communication distance becomes a high frequency band. You can see that it shifts.
The graph shown in FIG. 4B shows a case where the total width (short direction) of the first auxiliary antenna 20 is changed. The longer the total width of the first auxiliary antenna 20, the lower the frequency band of the peak communication distance. You can see that it shifts to.

The graph shown in FIG. 4C shows a case where the overall width (shortward direction) of the second auxiliary antenna 30 is changed to change the area of the second auxiliary antenna 30 exposed from the first auxiliary antenna 20. It can be seen that as the exposed area of the second auxiliary antenna 30 increases, the communication distance becomes longer, especially in the low frequency band.
The graph shown in FIG. 4D shows a case where the arrangement position of the same second auxiliary antenna 30 is moved to change the area where the second auxiliary antenna 30 is exposed from the first auxiliary antenna 20, and the second auxiliary antenna 30 is exposed. It can be seen that as the exposed area of the antenna 30 increases, the communication distance increases.
Further, when the entire second auxiliary antenna 30 is hidden by the first auxiliary antenna 20 and the exposed area is zero, the communicable frequency band and the communication distance are extremely high, as in the case of Comparative Example 2 of FIG. It turns out that it becomes low and becomes unusable for practical use.

From the results of FIGS. 3 and 4 above, by changing the dimensions (total length and width) of the first auxiliary antenna 20, the communicable frequency band can be moved and adjusted, and the second auxiliary antenna 30 can be moved and adjusted. It can be seen that the communication distance can be adjusted / changed by changing the area exposed from the first auxiliary antenna 20.
Therefore, when setting / adjusting the frequency band / communication distance, roughly adjust the total length / width of the first / second auxiliary antennas 20 and 30, and then change the arrangement position of the second auxiliary antenna 30.・ By making adjustments, fine adjustments can be made.

[Plane layout pattern]
Next, the planar arrangement pattern of the inlay 10 and the first / second auxiliary antennas 20 and 30 in the RF tag 1 of the embodiment will be described with reference to FIG.
5 (a) to 5 (d) are plan views schematically showing an example in which the inlay 10 of the RF tag 1 and the first and second auxiliary antennas 20 and 30 according to the present embodiment have different planar arrangement positions. Is.
In the example shown in the figure, the RF tag 1 has dimensions in the longitudinal direction and the lateral direction of the first auxiliary antenna 20 smaller than the dielectric layers 40 and 50 which are the base materials of the inlay 10 and the second auxiliary antenna 30. Is formed to be.

Specifically, for example, the first auxiliary antenna 20 is formed to have a longitudinal direction of about 110 mm and a lateral direction of about 20 mm corresponding to a half wavelength of the communication frequency of 920 MHz of the target inlay 10, and is used as a base material. The dielectric layers 40 and 50 are formed to have a size one size larger than that, for example, about 130 mm in the longitudinal direction and about 30 mm in the lateral direction.
Further, the inlay 10 and the second auxiliary antenna 30 can also be arranged without protruding onto the dielectric layers 40 and 50, and the first auxiliary antenna 20 can be arranged so as to be superposed on the IC chip and the loop circuit 11a of the inlay 10. The dimensions in the direction and the lateral direction are set to be smaller than those of the dielectric layers 40 and 50 and the first auxiliary antenna 20 (see FIG. 2).

As a result, the first auxiliary antenna 20 is laminated on the dielectric layers 40 and 50 so as not to overlap with at least a part of the inlay 10 and the second auxiliary antenna 30 laminated on the dielectric layers 40 and 50. Can be done.
Hereinafter, with reference to FIG. 5, a specific example of the plane arrangement pattern of the first auxiliary antenna 20 and the inlay 10 / second auxiliary antenna 30 will be shown.
In addition, in FIG. 5, in order to facilitate understanding, the inlay 10 and the second auxiliary antenna 30 exposed from the outer edge of the first auxiliary antenna 20 are shown so as to be directly visible, but in the actual RF tag 1, Since the dielectric layer 40 is laminated on the upper surface of the inlay 10 and the second auxiliary antenna 30, it cannot be directly viewed from the outside.

In the example shown in FIG. 5A, a part of the inlay 10 and the second auxiliary antenna 30 are exposed from both ends in the longitudinal direction of the first auxiliary antenna 20, respectively, and from the left end side of the first auxiliary antenna 20. The end of the antenna portion 12 on the left end side of the inlay 10 is exposed from the right end side of the first auxiliary antenna 20 to the right end of the second auxiliary antenna 30. The exposure length of the inlay 10 and the second auxiliary antenna 30 can be set to, for example, about 10 to 20 mm.
In the example shown in FIG. 5B, only a part of the second auxiliary antenna 30 is exposed from one end in the longitudinal direction of the first auxiliary antenna 20, and the second auxiliary antenna 20 is exposed from the right end side of the first auxiliary antenna 20. The right end of the antenna 30 is exposed. The exposure length of the second auxiliary antenna 30 can also be set to, for example, about 10 to 20 mm.

In the example shown in FIG. 5C, only a part of the inlay 10 is exposed from the other end in the longitudinal direction of the first auxiliary antenna 20, and the antenna portion of the inlay 10 is exposed from the left end side of the first auxiliary antenna 20. The left end of 12 is exposed. The exposure length of the inlay 10 can also be set to, for example, about 10 to 20 mm.
In the example shown in FIG. 5D, only a part of the second auxiliary antenna 30 is exposed from one end of the first auxiliary antenna 20 in the lateral direction, and the second auxiliary antenna 20 is second from the lower end side. The lower end of the auxiliary antenna 30 is exposed with a constant width over the entire longitudinal direction. The exposure width of the second auxiliary antenna 30 can be set to, for example, about 5 to 10 mm.
The arrangement / exposure pattern of the first auxiliary antenna 20 and the inlay 10 / second auxiliary antenna 30 as described above is merely an example. In addition to the pattern shown in FIG. 5, the first auxiliary antenna 20 includes the inlay 10. Of course, other arrangement / exposure patterns can be adopted as long as they are arranged so as not to overlap with at least a part of the second auxiliary antenna 30.

[Layered arrangement pattern]
Next, the laminated arrangement pattern of the RF tag 1 according to the present embodiment will be described with reference to FIG.
6 (a) to 6 (d) are side views schematically showing a laminated arrangement pattern of each component of the RF tag 1 according to the present embodiment.
As shown in the figure, the RF tag 1 according to the present embodiment is composed of five elements [inlay 10, first / second auxiliary antennas 20, 30, and dielectric layers 40, 50], and these are attachment targets. It is designed to be attached to and fixed to an object (back metal body 100, back non-metal body 200).

As shown in FIGS. 6A and 6B, the five elements constituting the RF tag 1 are [back surface metal body 100 → dielectric layer 50 → inlay 10 → second auxiliary antenna 30 → dielectric layer 40. → The first auxiliary antenna 20] may be stacked in this order, or the inlay 10 and the second auxiliary antenna 30 may be interchanged to [rear metal body 100 → dielectric layer 50 → second auxiliary antenna 30 → inlay 10 → dielectric. The body layer 40 → the first auxiliary antenna 20] may be stacked in this order.
Further, as shown in FIG. 6C, the dielectric layers 40 and 50 may be configured to integrally house and seal the inlay 10 and the second auxiliary antenna 30 inside by in-mold molding or the like. it can.
Further, as shown in FIG. 6D, the object to be attached to the RF tag 1 is not only a metal article / object, but also a non-metal article / object (non-metal back surface) such as a synthetic resin. Even in the case of 200), stable wireless communication can be performed.

[Inlay antenna]
Next, the configuration pattern of the antenna portion 12 of the inlay 10 of the RF tag 1 according to the present embodiment will be described with reference to FIG. 7.
FIG. 7 is a plan view showing a plan layout example of the second auxiliary antenna when the configuration pattern of the antenna portion 12 of the inlay 10 according to the present embodiment is different, and FIG. 7A is a plan view in which the antenna portion 12 constitutes a dipole antenna. In the case (b), the antenna unit 12 constitutes a monopole antenna, and in (c), the antenna unit 12 is composed of only the loop circuit 11a.
As shown in the figure, the antenna portion 12 provided in the inlay 10 is configured as a dipole antenna extending to both the left and right sides of the IC chip 11 (see FIG. 7A), or either the left or right side of the IC chip 11. It can be configured as a monopole antenna extending only to one side (see FIG. 7B), or can be configured as an antenna consisting only of a loop circuit 11a without a dipole antenna or a monopole antenna (FIG. 7). (C).

A general-purpose inlay is generally provided with a dipole antenna composed of conductors extending linearly on both sides (left and right) of the IC chip 11, but in the dipole antenna, the conductors constituting the antenna have, for example, 1/2 wavelength. Since it is provided so that it is symmetrical on both sides of the IC chip so that it has the same length as the above, when using the general-purpose inlay as it is, at least the length of the dipole antenna needs to be arranged and stored. The dimensions of the base material including the inlay and the protective cover must exceed the length of the dipole antenna (for example, 1/2 wavelength), which may limit the miniaturization of the RF tag and the degree of freedom in design. possible.
In addition, if the inlay is provided with an auxiliary antenna in addition to the antenna provided by the inlay, the auxiliary antenna functions as an inlay antenna so that wireless communication can be performed without a dipole antenna on the inlay side. become.

Therefore, in the present embodiment, the inlay 10 is configured to include dipole antennas extending on both sides of the IC chip 11 (loop circuit 11a), a configuration including a monopole antenna, and a loop not provided with a dipole antenna / monopole antenna. By providing only the circuit 11a, it is possible to perform good wireless communication of the inlay without being restricted by the size and form of the antenna of the inlay 10 and effectively utilizing the function of the auxiliary antenna. Can be done.
The inlay 10 including the antenna portion 12 composed of only the monopole antenna and the loop circuit 11a is removed by cutting a part or all of the dipole antenna portion by using, for example, a general-purpose inlay equipped with a dipole antenna. It can be configured by It can also be configured by manufacturing an inlay 10 having a monopole antenna having a predetermined length and shape, or an inlay 10 having only an IC chip 11 and a loop circuit 11a as a dedicated inlay.

[Dipole antenna]
FIG. 7A shows a case where the antenna portion 12 of the inlay 10 is configured as a dipole antenna.
In this case, the second auxiliary antenna 30 may be arranged so as not to overlap the IC chip 11 at least, and the second auxiliary antenna 30 is provided only on one of the antenna portions 12 extending on both the left and right sides of the IC chip 11. The second auxiliary antenna 30 can be arranged on top of each other on both the left and right antenna portions 12, respectively.

[Monopole antenna]
FIG. 7B shows a case where the antenna portion 12 of the inlay 10 is configured as a monopole antenna.
Also in this case, the second auxiliary antenna 30 may be arranged so as not to overlap the IC chip 11 at least, and the second auxiliary antenna 30 is arranged so as to overlap only the antenna portion 12 extending to the left and right sides of the IC chip 11. Further, the second auxiliary antenna 30 can be arranged so as to overlap the edge of the loop circuit 11a in which the antenna portion 12 is not formed, and further, both on the antenna portion 12 side and the loop circuit 11a side, respectively. The second auxiliary antenna 30 can also be arranged so as to overlap.
By arranging the second auxiliary antenna 30 on at least a part of the monopole antenna and the loop circuit 11a of the antenna unit 12 in this way, the communication characteristics of the inlay 10 can be adjusted and improved, and the inlay can be adjusted and improved. The length of the 10 (RF tag 1) in the longitudinal direction in a plan view can be reduced (shortened) as compared with the case of the inlay 10 provided with a dipole antenna.

[Loop circuit only]
FIG. 7C shows a case where the antenna portion 12 of the inlay 10 is configured to include only the loop circuit 11a without the dipole antenna or the monopole antenna.
In this case as well, the second auxiliary antenna 30 may be arranged so as not to overlap the IC chip 11 at least, and the second auxiliary antenna 30 may be placed on one edge or both edges of the loop circuits 11a on both the left and right sides of the IC chip 11. 2 Auxiliary antennas 30 can be arranged in an overlapping manner.
Also in this case, the second auxiliary antenna 30 is arranged so as to overlap the loop circuit 11a, so that the second auxiliary antenna 30 functions as the antenna portion 12 of the inlay 10, and the communication of the inlay 10 (RF tag 1) is performed. The characteristics can be adjusted and improved.

[Other forms]
The embodiment of the arrangement pattern of each component of the RF tag 1 has been described above with reference to FIGS. 2, 5 to 8, and further, the inlay 10 and the second auxiliary antenna 30 as shown in FIG. 8 have been described. An arrangement pattern can also be adopted.
In the example shown in FIG. 8A, when the antenna portion 12 of the inlay 10 is configured as a monopole antenna, a small planar second along the lower end edge of the loop circuit 11a facing the IC chip 11. This is a case where the auxiliary antennas 30 are arranged so as to overlap each other.
In the example shown in FIG. 8B, when the antenna portion 12 of the inlay 10 is composed of only the loop circuit 11a, a small linear th-order along the lower end edge of the loop circuit 11a facing the IC chip 11 2 This is a case where the auxiliary antennas 30 are arranged so as to overlap each other.

In the example shown in FIG. 8 (c), the linear second auxiliary antenna 30 shown in FIG. 8 (b) is continuously and extended in a plane on one side of the inlay 10, and extends to one side of the inlay 10. This is a case where it is formed and arranged as a pole antenna.
As described above, the form of the second auxiliary antenna 30 arranged so as to be overlapped with the inlay 10 can also be formed into a predetermined configuration / form according to the configuration / form of the inlay 10 and the antenna portion 12, and the inlay 10 can be formed. It is possible to flexibly and finely adjust and respond to the communication characteristics of.

As described above, according to the RF tag 1 of the present embodiment, the first auxiliary antenna 20 arranged on the uppermost surface of the RF tag 1 is protected to protect the inlay 10 arranged inside the tag from the external environment. It can function as a cover (top cover).
Further, the second auxiliary antenna 30 arranged on the inlay 10 inside the RF tag 1 can function as an antenna of the inlay 10 together with the first auxiliary antenna 20. As a result, even if the inlay 10 is covered with the 1st and 2nd auxiliary antennas 20 and 30, good wireless communication characteristics can be obtained without impairing the communication function.

In particular, by forming the first auxiliary antenna 20 which is the top cover (protective cover) of the RF tag 1 with a metal member (metal plate), it is durable against physical forces such as impact and pressure applied to the RF tag 1 from the outside. It is possible to improve the property, impact resistance, pressure resistance, etc., and effectively prevent the inlay 10 arranged inside from being damaged or damaged by an external force or an impact.
Further, the first auxiliary antenna 20 that functions as a protective cover for such an RF tag 1 is arranged so as not to overlap with at least a part of the inlay 10 and / or the second auxiliary antenna 30, and further, the second auxiliary antenna 30 is arranged. However, by arranging the inlay 10 so as not to overlap the IC chip 11 at least, the first and second auxiliary antennas 20 and 30 function as antennas of the inlay 10, and the communication characteristics of the RF tag 1 are improved. It is possible to maintain and improve the condition.

Therefore, even if a part or all of the inlay 10 is covered by the first / second auxiliary antennas 20 and 30, the electrical characteristics of the inlay 10 are not affected, and the antenna portion 12 of the inlay 10 The antenna functions of the first and second auxiliary antennas 20 and 30 can be used as effectively as possible to maximize the antenna gain.
As described above, in the RF tag 1 according to the present embodiment, the first and second auxiliary antennas 20 and 30 are arbitrarily provided while the antenna portion 12 and the loop circuit 11a included in the RF tag 1 itself are effectively and maximally functioning. It can be configured and arranged, the degree of freedom in designing the RF tag 1 can be improved, and the 1st and 2nd auxiliary antennas 20 and 30 most suitable for the inlay 10 to be used can be adjusted and changed. , It becomes possible to realize a metal-compatible RF tag that can obtain good communication characteristics.

Although the RF tag of the present invention has been described above by showing a preferred embodiment, the RF tag according to the present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention. It goes without saying that it is possible.

For example, in the above-described embodiment, for example, an aluminum metal container or a metal housing is assumed as an article / object to be used by attaching the RF tag according to the present invention. The articles and objects that can be used are not limited to aluminum metal containers and metal housings.
That is, the RF tag according to the present invention is applied to any article or object as long as the RF tag is used and predetermined information / data is read / written via a reader / writer. can do. For example, other than aluminum metal containers and metal housings, it is suitably used for any metal articles / objects such as metal heaters, electric appliances, tableware, cooking utensils, furniture, furniture, containers, automobiles, etc. be able to.

The present invention is an RF tag having a structure for protecting an inlay to enhance durability, impact resistance, etc., which is used by being attached to an arbitrary article or object such as a pallet or a container for cargo. It can be preferably used.

1 RF tag 10 Inlay 11 IC chip 11a Loop circuit 12 Antenna part 13 Encapsulating film 20 1st auxiliary antenna (protective cover)
30 Second auxiliary antenna 40 Dielectric layer 50 Dielectric layer 100 Back metal body (mounting object)
200 Back non-metal body (mounting object)

Claims (7)

1. An inlay that includes at least an IC chip and a loop circuit that electrically couples to the IC chip.
   The first auxiliary antenna arranged so as to overlap the IC chip and the loop circuit of the inlay,
   A second auxiliary antenna arranged so as not to overlap the IC chip with respect to the inlay,
   A dielectric layer arranged so as to overlap the inlay and the second auxiliary antenna,
   With
   The first auxiliary antenna
   The dielectric layer is arranged on a surface opposite to the arrangement surface of the inlay so as not to overlap with at least a part of the inlay and / or the second auxiliary antenna.
   An RF tag characterized in that the inlay, the first auxiliary antenna, and the second auxiliary antenna are electromagnetically coupled.
2. A second dielectric layer is arranged on the surface of the inlay opposite to the arrangement surface of the dielectric layer.
   The RF tag according to claim 1, wherein the second dielectric layer is formed together with the dielectric layer in a case shape that covers the entire inlay and the second auxiliary antenna.
3. The inlay
   The IC chip, the antenna portion including the loop circuit, and the base material on which the IC chip and the antenna portion are mounted are provided.
   The antenna part
   Claim 1 or claim 1, wherein only the loop circuit is composed of either the loop circuit and a monopole antenna connected to the loop circuit, or the loop circuit and a dipole antenna connected to the loop circuit. 2 The RF tag described.
4. The RF tag according to claim 2, further comprising a back metal body arranged on a surface of the second dielectric layer opposite to the arrangement surface of the first auxiliary antenna.
5. The first auxiliary antenna
   The RF tag according to any one of claims 1 to 4, wherein the RF tag is composed of a predetermined metal plate that functions as a protective member for the inlay.
6. The RF tag according to any one of claims 1 to 5, wherein the length of the long side of the first auxiliary antenna is a half wavelength of the communication frequency of the inlay.
7. The RF tag according to any one of claims 1 to 6, wherein the first auxiliary antenna and the second auxiliary antenna are not formed with a notch.

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