JP7121403B2 - RF tag device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an RF tag device for managing inventory management, physical distribution management, etc. of tubular metal materials such as high-pressure pipes. More particularly, the present invention relates to an RF tag device that can be effectively read by a reading device even when the RF tag is attached to a metal material having a tubular shape, because the communication distance is long and the opening area is widened.

In recent years, RFID (Radio Frequency Identification) technology has been used in management systems for inventory management, physical distribution management, and the like of products and parts. In a system using this RFID technology, wireless communication is performed between an RF tag and a reader/writer (hereinafter referred to as a reader), and identification information and the like stored in the RF tag are read by the reader.
For example, Patent Literature 1 (WO2007/000807) discloses a radio frequency identification tag that is thin and flexible, can communicate even when attached to metal, and has a reduced manufacturing cost.

In the radio frequency identification tag described in Patent Document 1, an inverted F antenna (10) has a radiating element (11), a short pin (12), a feeder (13) and a ground plane (14), and a film It is formed flat on the surface of (30). The film (30) is, for example, an insulating film such as polyethylene terephthalate. It is attached so as to protrude from a metal housing (40) of equipment or the like.

Patent Document 2 (Japanese Unexamined Patent Application Publication No. 2003-85501) discloses a contactless IC tag that can communicate with an external device (reader/writer) even when attached to a conductor such as metal.

The non-contact IC tag described in Patent Document 2 is a non-contact IC tag capable of non-contact communication with an external device by generating a potential difference between two antennas by an electrostatic coupling method. mounting an insulating layer 11 that can be attached to and prevents conduction with the conductor 40, a conductive layer 12 formed on the insulating layer 11, and an IC chip 13D, part of which is formed on the conductive layer 12; An IC chip mounting portion 13 is attached to a conductor 40 at the other portion, the conductive layer 12 is used as a first antenna, and the conductor 40 is used as a second antenna.

Patent Document 3 (WO2009/069199) relates to a metal pipe managed by an RF tag. The metal pipe is managed by the RF tag by attaching the RF tag having an IC chip connected to the metal pipe so that it functions as an antenna of the RF tag.

The RF tag described in Patent Document 3 is provided inside a metal pipe having a slot having a predetermined length in the longitudinal direction, and a power feeding part that feeds power to the slot in order to make the metal pipe function as an antenna. and an IC (Integrated Circuit) chip provided inside the metal pipe and connected to the power feeder.

WO2007/000807 JP-A-2003-85501 WO2009/069199

However, in the radio frequency identification tag disclosed in US Pat. Therefore, it cannot be attached to tubular metal materials such as high-pressure pipes because the portion protruding from the metal housing becomes an obstacle.

The non-contact IC tag disclosed in Patent Document 2 has the disadvantage that the communication distance is very short because a potential difference is generated between the two antennas by the electrostatic coupling method.
The invention disclosed in Patent Document 3 cannot be applied to metal materials that cannot be provided with slots because it is necessary to provide slots in the metal pipe.

The main object of the present invention is to provide an RF tag device that can be effectively read by a reader with a long communication distance and a wide opening area even when the RF tag is attached to a metal material having a tubular shape such as a high-pressure pipe. is to provide
Another object of the present invention is to provide an RF tag device capable of simultaneously reading RF tags fixed to a plurality of metal materials even when a plurality of metal materials are bundled or stacked. is.

(1)
An RF tag device according to one aspect is an RF tag device attached to a metal material having a tubular shape, the RF tag device including a fixture and an RF tag, the fixture having a tubular shape. A flat plate portion attached to the open end of the metal material, and one or more hooks extending from the back surface of the flat plate portion into the metal material having a tubular shape and engaging with the inner peripheral surface of the metal material having a tubular shape. and a stop piece for fixing the RF tag to the surface of the flat plate portion.

In this case, the fixing jig is attached to the metal material by fixing the RF tag to the fixing portion of the flat plate portion of the fixing jig and engaging the locking piece of the fixing jig with the inner peripheral surface of the metal material. Here, by attaching the RF tag to the flat plate portion of the fixing jig with an electrically insulating attaching member, a capacitor is formed, and an inductance of the RF tag and a resonance circuit can be formed.

In general, if the metal material has a diameter of 16 cm or less and the RF tag is housed in the metal material, there arises a problem that the RF tag cannot receive radio waves from the reader.
However, in the present invention, since the RF tag can be exposed while being fixed to the outside of the metal material, radio waves from the reader can be reliably received.

That is, the radio waves from the reader are received by one waveguide element (first waveguide element) of the RF tag, and the first waveguide element of the RF tag and the other second waveguide element of the RF tag ( ground element), and emitted from the second waveguide element to a metal pipe via a fixture. That is, since the RF tag and the fixing jig are capacitively coupled through the dielectric made of the sticking member, the fixing jig functions as an antenna.

Therefore, the entire metal material can act as an antenna. In this way, radio waves from the RF tag can be sent to the reader through the metal material, and radio waves from the reader can be received by the RF tag through the metal material.
As a result, it is possible to reliably drive the RF tag and read the non-directional RF tag with a long communication distance.

Therefore, when metal pipes such as a plurality of pipes are bundled or stacked and stored, even if the RF tag is hidden by the metal pipes and cannot receive radio waves, the RF tag attached to each metal pipe history information, etc. can be read at the same time.

(2)
An RF tag device according to a second aspect of the invention is an RF tag device according to one aspect, wherein the RF tag includes an antenna and an IC chip that operates based on radio waves transmitted from a reader, and the antenna includes an insulating layer A first waveguide element and a second waveguide element provided via, a feeding section having one end electrically connected to the second waveguide element, and one end electrically connected to the first waveguide element , and a short-circuit portion having the other end electrically connected to the second waveguide element, wherein the signal is transmitted from the reader by the insulating layer, the first waveguide element, the second waveguide element, the feeding portion, and the short-circuit portion. a first waveguide element, a short-circuiting portion, a second waveguide element, and an inductor pattern configured to receive radio waves; A resonant circuit that resonates in the frequency band of radio waves may be configured with the configured capacitor.

In this case, the RF tag has an antenna and an IC chip. The RF tag receives a radio wave (carrier wave) transmitted from the antenna of the reader with a waveguide element (antenna) of the RF tag. Then, identification data of the metal material recorded in the IC chip is put on the reflected wave and sent back to the reading device. This allows the RF tag to communicate with the reader without bringing the reader into contact with the RF tag.

(3)
An RF tag device according to a third aspect of the invention is the RF tag device according to one aspect or the second aspect of the invention, wherein the one or more locking pieces bias against the inner peripheral surface of the metal material having a tubular shape. It may consist of an urging member.

In this case, when the fixing jig is attached to the metal material, the fixing jig can be easily attached to the metal material by elastically deforming the locking piece. Since the stop piece presses against the inner peripheral surface of the metal material, the fixing jig can be securely attached to the metal material.

(4)
An RF tag device according to a fourth aspect of the present invention is the RF tag device according to the first aspect to the third aspect of the invention, wherein the metal material may be a high-pressure pipe.

In this case, since the reading device reads the material information from the RF tag attached to the high-pressure pipe, it is possible to manage the movement and storage of the high-pressure pipe.

1 is a schematic cross-sectional view showing an example of a state in which an RF tag device according to this embodiment is attached to an open end of a high-pressure pipe; FIG. 1 is a schematic perspective view from the surface side showing an example of an RF tag device according to this embodiment; FIG. 1 is a schematic perspective view from the back side showing an example of an RF tag device according to this embodiment; FIG. 1 is a schematic perspective view showing an example of an RF tag; FIG. FIG. 2 is a schematic perspective view showing an example of an RF tag showing the back side; FIG. 2 is a schematic developed view showing an example of an RF tag; FIG. 2 is a diagram showing an example of an equivalent circuit of high-pressure piping to which the RF tag device of FIG. 1 is attached;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same reference numerals are given to the same parts. Moreover, in the case of the same reference numerals, their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

[Embodiment]
FIG. 1 is a schematic cross-sectional view showing an example of a state in which an RF tag device 110 according to this embodiment is attached to an open end 210 of a high-pressure pipe 200, and FIGS. It is a schematic perspective view showing an example of such an RF tag device 110. FIG.

The RF tag device 110 of the present invention is attached to the open end 210 of the metallic material 200 having a tubular shape. Here, the metal material 200 is a member having conductivity, and is usually made of a metal material such as steel or aluminum.

Applications of the metal material 200 having a tubular shape are not limited, but may be civil engineering materials, plant materials, automobile materials, construction materials, and the like. In this embodiment, an example in which the RF tag device 110 of the present invention is attached to a high-pressure pipe used as civil engineering materials and plant materials will be described below.

The high-pressure pipe 200 includes those with both ends open, those in which at least one end of the high-pressure pipe is deformed, etc., and those in which a connection member such as a flange is welded to at least one end of the high-pressure pipe.

(RF tag device 110)
As shown in FIGS. 1 and 2, RF tag device 110 includes fixture 300 and RF tag 100 .

(fixing jig 300)
The fixing jig 300 includes a flat plate portion 320 attached to the open end portion 210 of the high-pressure pipe 200, and a plate portion 320 extending from the back surface of the flat plate portion 320 into the high-pressure pipe 200 and engaged with the inner peripheral surface of the high-pressure pipe 200. or a plurality of locking pieces 330.

That is, the flat plate portion 320 of the fixing jig 300 is formed along the opening of the high-pressure pipe 200 , and the locking piece 330 has a shape extending in the longitudinal direction of the high-pressure pipe 200 .

(Flat plate portion 320)
The shape of flat plate portion 320 in the present embodiment is mainly a disc shape. Note that the shape of the flat plate portion 320 is not limited. The shape of the flat plate portion 320 can be, for example, a substantially disc shape so as to match the shape of the opening of the high-pressure pipe 200 .
The size of the flat plate portion 320 is formed to be large enough to close the opening of the high-pressure pipe 200 . The outer shape of the flat plate portion 320 is formed slightly larger than the outer shape of the high-pressure pipe 200 .

In this embodiment, as shown in FIGS. 2 and 3, two locking pieces 330 are provided at opposing positions around the flat plate portion 320 so as to protrude in a direction perpendicular to the planar direction of the flat plate portion 320. . Although the shape of the locking piece 330 is formed in a rectangular shape, the shape of the locking piece 330 can be arbitrarily designed such as a triangular shape. The width and length of the locking piece 330 can also be arbitrarily designed. Recesses 322 are formed at positions facing each other around the flat plate portion 320 where the locking pieces 330 are not formed.
Alternatively, a configuration may be used in which a convex portion is formed on the locking piece 330 and locked to the inner peripheral surface of the high-pressure pipe 200 by the convex portion.

The distance between the two opposing locking pieces 330 is set substantially equal to the inner diameter of the high-pressure pipe 200 . As a result, the engaging piece 330 can be fixed to the R portion of the inner peripheral surface of the high-pressure pipe 200 by having a predetermined linear width.

As shown in FIGS. 2 and 3, in the present embodiment, fixture 300 is made by processing a conductive plate such as a disk-shaped metal plate. The fixing jig 300 is formed by cutting and raising a locking piece 330 that locks onto the inner peripheral surface of the high-pressure pipe 200 around a conductive plate. One or two locking pieces 330 may be provided around the flat plate portion 320, or three or four or more locking pieces 330 may be provided.

The manufacturing of the fixture 300 can be carried out as follows.
Two parallel slits are formed from the periphery of the plate at four locations around the conductive plate. Next, by bending the area surrounded by the two slits at right angles to one side of the plate, the locking piece 330 protrudes in the direction orthogonal to the surface of the plate.

In addition, parallel slits are formed around the plate material at locations where the locking pieces 330 are not formed, and recesses 322 are formed by removing the regions surrounded by the two slits.

The RF tag 100 is fixed to the surface side of the fixing jig 300 configured in this manner (the side exposed to the outside when the fixing jig 300 is attached to the open end of the high-pressure pipe 200).

This RF tag 100 is fixed to the flat plate portion 320 of the fixing jig 300 so that both ends of the RF tag 100 are arranged in the region between the locking piece 330 and the recess 322 of the fixing jig 300 .

A known method can be used to fix the RF tag 100 to the fixture 300 . For example, the RF tag 100 can be adhered to the fixing jig 300 using an electrically insulating adhesive, adhesive, double-sided adhesive tape, or the like. For example, the RF tag 100 can be attached to the flat plate portion 320 of the fixture 300 using an electrically insulating attachment member.

(RF tag 100)
Next, the configuration of the RF tag 100 fixed to the fixing jig 300 will be described in detail.

As shown in FIGS. 4 to 6, the RF tag 100 includes an antenna 10 and an IC chip 80 that is connected to a power supply unit 50 and operates based on radio waves emitted by a reader (not shown). .

(antenna 10)
The antenna 10 includes a first waveguide element 20 , a second waveguide element 30 , a first insulating base material 40 , a power supply section 50 and a short circuit section 60 .

The first insulating base material 40 is formed in a rectangular plate shape and has an upper surface (first main surface) and a lower surface (second main surface) opposite to the first main surface. The first insulating base material 40 is, for example, a substantially rectangular parallelepiped, but is not limited thereto. For example, it may be disc-shaped, or it may have an arc-shaped cross section. Preferably, the first insulating base material 40 has a shape corresponding to the surface shape of the fixing jig 300 at the position where the RF tag 100 is attached.

As shown in FIG. 4, the first waveguide element 20 is provided on the top surface of the first insulating base material 40 . As shown in FIG. 5, the second waveguide element 30 is provided on the bottom surface of the first insulating base material 40 . Both the first waveguide element 20 and the second waveguide element 30 are rectangular, and are formed by etching or pattern printing a metal thin film such as aluminum.

The first waveguide element 20 and the second waveguide element 30 have the same shape. In the present application, the term "same shape" is not limited to being the same in a strict sense, and the term "same shape" includes a slight difference due to the structure of the antenna. For example, when an IC chip 80, which will be described later, is provided on the same plane as the first waveguide element 20, in order to arrange the IC chip 80, as shown in FIG. It is necessary to provide a recess 25 in the part. In this case, the shapes of the first waveguide element 20 and the second waveguide element 30 are not exactly the same. However, since the first waveguide element 20 has the same rectangular shape as the second waveguide element 30, the first waveguide element 20 and the second waveguide element 30 are assumed to have the same shape.

The feeding section 50 is provided on the side surface of the first insulating base material 40 and has one end electrically connected to the second waveguide element 30 . The short-circuit portion 60 is provided on the side surface of the first insulating base material 40, and has one end electrically connected to the first waveguide element 20 and the other end electrically connected to the second waveguide element 30. .
As shown in FIG. 4, the feeding portion 50 and the short-circuit portion 60 are members provided in parallel with each other on the sheet 70 so as to span the first waveguide element 20 and the second waveguide element 30. is.

Note that the power supply portion 50 and the short-circuit portion 60 do not have to be provided in parallel with each other. Further, the feeding portion 50 and the short-circuit portion 60 may be integrally formed at the same time as the first waveguide element 20 and the second waveguide element 30 are formed. Alternatively, after forming the power feeding portion 50 and the short-circuiting portion 60 separately, the respective ends may be joined to the first waveguide element 20 and the second waveguide element 30 .

As shown in FIGS. 4, 5, and 6, the first waveguide element 20, the second waveguide element 30, the feeding portion 50, and the short-circuit portion 60 are formed on an insulating sheet 70. It is attached to the outer surface of the first insulating base material 40 via a sheet 70 that is bent at the side portions of the insulating base material 40 .
That is, as shown in FIG. 6, a flexible sheet 70 having a first waveguide element 20, a second waveguide element 30, a power supply portion 50 and a short circuit portion 60 formed on one side thereof is attached to the power supply portion 50 and the short circuit portion. The antenna 10 can be easily manufactured by bending the parts 60 together and attaching them to the front and rear surfaces of the first insulating base material 40 .

As the material of the sheet 70, it is possible to use a flexible insulating material such as PET, polyimide, or polyvinyl chloride. Although the thickness of the sheet 70 is not particularly limited, it is generally about several tens of micrometers. Also, the surfaces of the waveguide elements 20 and 30 may be treated with an insulating film.

Also, although the first waveguide element 20 and the second waveguide element 30 are formed on the sheet 70 (base material), they do not necessarily have to be formed on the sheet 70 . For example, the first waveguide element 20 and the second waveguide element 30 may be formed singly. Alternatively, the sheet 70 may be peeled off after the first waveguide element 20 and the second waveguide element 30 are formed on the sheet 70 .

The first insulating base 40, the first waveguide element 20, the second waveguide element 30, the feeding portion 50, and the short-circuit portion 60 constitute a plate-like inverted F antenna. This plate-shaped inverted F antenna receives radio waves transmitted from a reader (not shown). When the first waveguide element 20 absorbs radio waves, the second waveguide element 30 acts as a conductor ground plane.
On the other hand, when the second waveguide element 30 absorbs radio waves, the first waveguide element 20 acts as a conductor ground plane. In other words, the waveguide elements 20 and 30 can function as both a waveguide element and a conductive ground plate depending on the mode of use of the RF tag 100 .

As shown in FIG. 4, the first waveguide element 20 has a total length A of sides 20a to 20f around it that is λ/4, λ/2, 3λ/4, or 5λ/8. is designed to Here, λ is the wavelength of radio waves transmitted from the reader. Note that the wavelength λ of the radio wave is not particularly limited as long as it is within the range in which the RF tag 100 can be used. As shown in FIG. 5, the second waveguide element 30 is designed such that the sum B of the lengths of its surrounding sides 30a-30d is approximately equal to the sum A. As shown in FIG.

As described above, the first waveguide element 20 and the second waveguide element 30 have the same shape, and the total lengths A and B of the sides around the waveguide elements 20 and 30 are λ/4, Approximately equal to λ/2, 3λ/4, or 5λ/8. This makes it possible to easily set the resonance frequency of the plate-shaped inverted-F antenna.

It should be noted that the planar shape of each waveguide element 20, 30 is not limited to a rectangular shape as long as the total lengths A and B of the sides around each waveguide element 20, 30 are any of the above values. For example, each of the waveguide elements 20 and 30 may have a rectangular shape by cutting the central portion thereof.

Alternatively, an insulator may be used as the first insulating base material 40 . As a result, it is possible to secure an aperture area of a certain size and improve the sensitivity of the plate-shaped inverted F antenna. For example, expanded polystyrene can be used as the first insulating base material 40 .

Also, the first insulating base material 40 may be a dielectric. As the first insulating base material 40, a dielectric having a dielectric constant of 1 or more and 20 or less can be used, for example. When a dielectric material with a large dielectric constant (for example, ceramic) is used, the capacitance of the capacitor 93 increases, so the opening areas of the first waveguide element 20 and the second waveguide element 30 decrease, and the RF tag 100 It can be made smaller. However, since the gain of the antenna 10 is reduced, the communicable distance (communication distance) with the reader is shortened. If a relatively long communication distance of several meters or more is required, a dielectric with a low dielectric constant is used as the first insulating base material 40 . In this case, the dielectric constant is preferably 5 or less.

The antenna 10 configured as described above constitutes a resonance circuit that resonates in the frequency band of radio waves transmitted from the reading device and received by the plate-shaped inverted F antenna. This resonance circuit is composed of an inductor pattern L and a capacitor (first capacitor) 93 (see FIG. 7).
Here, the inductor pattern L is composed of the first waveguide element 20, the short-circuit portion 60, the second waveguide element 30, and the feeding portion 50, and the capacitor 93 is composed of the first waveguide element 20, the second waveguide element 30 and the first insulating base material 40 . This resonant circuit enables the plate-shaped inverted F antenna to receive radio waves (carrier waves) transmitted from the reader with high sensitivity, so that the reading performance of the RF tag 100 can be improved. Furthermore, the power supply voltage generated by the IC chip 80, which will be described later, can be increased.

(Antenna manufacturing method)
Next, a method for manufacturing the antenna 10 will be described.
First, as shown in FIG. 6, along the direction H orthogonal to the longitudinal direction of the feeding portion 50 and the short-circuiting portion 60, the feeding portion 50 and the short-circuiting portion 60 are respectively formed into the first waveguide element 20 and the second waveguide element. The first waveguide element 20 and the second waveguide element 30 are made to face each other by bending in the vicinity of the junction with 30 .
Next, the first waveguide element 20 is attached to the upper surface of the first insulating substrate 40 with an adhesive or the like, and the second waveguide element 30 is attached to the lower surface of the first insulating substrate 40 . Thereby, a plate-shaped inverted F antenna as the antenna 10 can be manufactured.

The antenna 10 functioning as a plate-like inverted F antenna has the first waveguide element 20 and the second waveguide element 20 on the front and back surfaces of the first insulating base material 40 by bending the feeding portion 50 and the short-circuit portion 60 as described above. It is produced by sticking the wave elements 30 respectively. Therefore, the structure of the antenna can be simplified and the manufacturing cost can be reduced as compared with the case of a conventional patch antenna provided with a coaxial line or strip line for feeding.

(IC chip)
The IC chip 80 is provided between the first waveguide element 20 and the feeding section 50, as shown in FIG. The IC chip 80 is arranged on the upper surface side of the first insulating base material 40 (on the same plane as the first waveguide element 20).
Note that the IC chip 80 may be arranged on the side surface of the first insulating base 40 as long as it functions as a plate-shaped inverted F antenna. Alternatively, an external power supply may be connected to the IC chip 80 so that the IC chip 80 operates with the voltage supplied from the external power supply.

The IC chip 80 operates based on radio waves from the reading device received by the plate-shaped inverted F antenna of the antenna 10 .
Specifically, the IC chip 80 first rectifies a part of the carrier wave transmitted from the reader to generate the power supply voltage necessary for the IC chip itself to operate. Then, the IC chip 80 operates the logic circuit for control in the IC chip 80 and the non-volatile memory in which the specific information of the pipe 200 (metal material) and the like are stored by the generated power supply voltage.
The IC chip 80 also operates a communication circuit or the like for transmitting and receiving data to and from the reading device.

Some IC chips 80 include a capacitor inside, and the IC chip 80 has stray capacitance. Therefore, it is preferable to consider the equivalent capacitance inside the IC chip 80 when setting the resonance frequency of the resonance circuit. In other words, the resonance circuit preferably has a resonance frequency set in consideration of the inductance of the inductor pattern L, the capacitance of the capacitor 93 and the equivalent capacitance inside the IC chip 80 . Additionally, the capacitance of the second capacitor is taken into account, as will be discussed below.

Thus, the RF tag 100 has the antenna 10 and the IC chip 80. FIG. The RF tag 100 receives radio waves (carrier waves) transmitted from the reader by the antenna 10 of the RF tag 100 . Then, identification data of the pipe 200 and the like recorded in the IC chip 80 are carried on the reflected wave and sent back to the reader. This allows the RF tag 100 to communicate with the reader without bringing the reader into contact with the RF tag 100 .

(Attachment of RF tag device 110 to high-pressure pipe 200)
The RF tag device 110 configured as described above can be attached to the high-pressure pipe 200 as follows.

As shown in FIG. 1, the RF tag device 110 can be easily attached to the open end 210 of the high-pressure pipe 200 by inserting and locking the pair of locking pieces 330 into the opening of the high-pressure pipe 200 .

When the fixing jig 300 is attached to the high-pressure pipe 200 , the locking piece 330 preferably comprises a biasing member that biases the high-pressure pipe 200 from its inner peripheral surface toward its outer peripheral surface. Preferably, the locking piece 330 also has elasticity.
When the pair of locking pieces 330 are inserted into the opening of the high-pressure pipe 200, the pair of locking pieces 330 are elastically deformed inward to slide the pair of locking pieces 330 along the inner surface of the high-pressure pipe 200. and can be locked to the inner peripheral surface of the high-pressure pipe 200 as shown in FIG.

After the fixing jig 300 is attached to the high-pressure pipe 200 , the restoring force of the pair of locking pieces 330 presses the locking pieces 330 against the inner peripheral surface of the high-pressure pipe 200 . Therefore, even if the high-pressure pipe 200 receives an impact from the outside, the fixing jig 300 will not easily come off from the high-pressure pipe 200 .

When the fixing jig 300 is attached to the high-pressure pipe 200 , the peripheral end portion of the flat plate portion 320 contacts the end face of the high-pressure pipe 200 to substantially close the opening of the high-pressure pipe 200 .

In addition, when the RF tag device 110 is attached to the high pressure pipe 200 , the inside of the high pressure pipe 200 can be ventilated through the concave portion 34 formed in the RF tag device 110 . Also, the RF tag device 110 can be easily removed from the high-pressure pipe 200 by inserting a tool or the like into the high-pressure pipe 200 through the recess 34 .

(Equivalent circuit)
FIG. 7 is a diagram showing an example of an equivalent circuit of the high-pressure pipe 200 to which the RF tag device 110 shown in FIG. 1 is attached.
As shown in FIG. 7, the equivalent circuit of the RF tag 100 consists of an inductor pattern L, a capacitor 93, and an IC chip 80. FIG. The inductor pattern L, the capacitor 93 and the IC chip 80 form a resonant circuit that resonates in the frequency band of radio waves transmitted from the reader.
The resonance frequency f [Hz] of this resonance circuit is given by equation (1). The value of the resonance frequency f is set so as to be included in the frequency band of radio waves transmitted from the reader.

In equation (1), La means the inductance of the inductor pattern L, Ca means the electrostatic capacity of the capacitor 93, and Cb means the equivalent capacity inside the IC chip 80.

Here, some IC chips 80 include a capacitor inside, and the IC chip 80 has stray capacitance. Therefore, when setting the resonance frequency f of the resonance circuit, it is preferable to consider the equivalent capacitance Cb inside the IC chip 80 .

That is, the resonance circuit preferably has a resonance frequency f set in consideration of the inductance of the inductor pattern L, the capacitance of the capacitor 93 and the equivalent capacitance Cb inside the IC chip 80 . As Cb, for example, a capacitance value published as one of specifications of the IC chip to be used can be used.

As described above, by considering the equivalent capacitance Cb inside the IC chip 80, the resonance frequency f of the resonance circuit can be accurately set to the frequency band of radio waves. As a result, the reading performance of the RF tag 100 can be further improved. Also, the power supply voltage generated by the IC chip 80 can be further increased.

Furthermore, in the high-pressure pipe 200 to which the RF tag device 110 is attached, the RF tag 100 is attached to the flat plate portion 320 of the fixing jig 300 with an electrically insulating attaching member, so that the capacitor (second capacitor) 270 is formed, and can form a resonance circuit with the inductance of the RF tag 100 .

As shown in FIG. 7, the second capacitor 270 is connected in series with a capacitor 93 (first capacitor) composed of the first waveguide element 20, the second waveguide element 30, and the first insulating substrate 40. there is Therefore, the combined capacitance of the first capacitor 93 and the second capacitor 270 may change, and the resonance frequency of the resonance circuit of the RF tag 100 may change significantly.

Specifically, when the capacity of capacitor 270 is much smaller than the capacity of capacitor 93 , the combined capacity is much lower than the capacity of capacitor 93 . This means that when the RF tag 100 is placed in the high-pressure pipe 200, the resonance frequency of the resonance circuit of the RF tag 100 changes greatly, degrading the reading performance of the RF tag 100. FIG.

Therefore, in this embodiment, the capacity of the capacitor 270 can be made equal to or greater than the equivalent capacity inside the IC chip 80 . As a result, the combined capacitance of the capacitor 93 and the capacitor 270 can be prevented from significantly decreasing, and performance degradation of the RF tag 100 can be suppressed. It is preferable that the capacity of the capacitor 270 is at least twice the equivalent capacity inside the IC chip 80 .

Radio waves from the reader are received by one waveguide element (first waveguide element) 20 of the RF tag 100, and are transmitted between the first waveguide element 20 of the RF tag 100 and the other second waveguide element of the RF tag 100. It passes through the circuit of the IC chip 80 connected to the wave element (ground element) 30 and is emitted from the second waveguide element 30 to the high-pressure pipe 200 via the fixture 300 . That is, since the RF tag 100 and the fixing jig 300 are capacitively coupled via the dielectric made of the adhesive member, the fixing jig 300 functions as an antenna.

Therefore, the entire high-pressure pipe 200 can act as an antenna. In this manner, radio waves from the RF tag 100 can be sent to the reader through the high-pressure pipe 200 and radio waves from the reader can be received by the RF tag 100 through the high-pressure pipe 200 .
As a result, it is possible to reliably drive the RF tag 100 and read the RF tag 100 which is omnidirectional and has a long communication distance.

In order to protect the RF tag device 110 attached to the open end of the high pressure pipe 200 , a cap covering the RF tag device 110 may be attached to the end of the high pressure pipe 200 . The cap can be made of an electrically insulating member, for example, made of synthetic resin.

In the present invention, the RF tag device 110 corresponds to the "RF tag device", the RF tag 100 corresponds to the "RF tag", the IC chip 80 corresponds to the "IC chip", and the inductor pattern L corresponds to the "inductor The capacitor 93 corresponds to the "capacitor", the antenna 10 corresponds to the "antenna", the high-pressure pipe 200 corresponds to the "high-pressure pipe", the "tube-shaped metal material", corresponds to the "fixing jig", the flat plate portion 320 corresponds to the "flat plate portion", and the locking piece 330 corresponds to the "locking piece".

Although one preferred embodiment of the invention is described above, the invention is not so limited. It is understood that various other embodiments can be made without departing from the spirit and scope of the invention. Furthermore, in this embodiment, the actions and effects of the configuration of the present invention are described, but these actions and effects are examples and do not limit the present invention.

REFERENCE SIGNS LIST 10 antenna 20 first waveguide element 30 second waveguide element 50 feeding section 60 short circuit section 80 IC chip 93 capacitor 100 RF tag 110 RF tag device 200 high pressure pipe 300 fixture 320 flat plate section 330 locking piece

Claims (3)

An RF tag device attached to a metal material having a tubular shape,
The RF tag device
a fixture;
an RF tag;
The RF tag includes an antenna,
an IC chip that operates based on radio waves transmitted from the reading device,
The fixing jig includes a flat plate portion attached to an open end portion of the metal material having a tubular shape;
one or more locking pieces extending from the back surface of the flat plate portion into the metal material having the tubular shape and being locked to the inner peripheral surface of the metal material having the tubular shape;
The antenna is
a first waveguide element and a second waveguide element provided via an insulating layer;
a feeding section having one end electrically connected to the second waveguide element;
a short circuit part having one end electrically connected to the first waveguide element and the other end electrically connected to the second waveguide element;
configured to receive radio waves transmitted from the reading device by the insulating layer, the first waveguide element, the second waveguide element, the power supply section, and the short circuit section;
An inductor pattern composed of the first waveguide element, the short-circuit portion, the second waveguide element and the feeding portion, and composed of the first waveguide element, the second waveguide element and the insulating layer. The capacitor constitutes a resonant circuit that resonates in the frequency band of the radio waves,
An RF tag device, wherein the RF tag is fixed to the surface of the flat plate portion. 2. The RF tag device according to claim 1 , wherein said one or more locking pieces comprise a biasing member that biases against the inner peripheral surface of said tubular metal material. 3. The RF tag device according to claim 1, wherein said metal material is high-pressure piping.

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