JP2011015099A - Radio communication improving sheet, radio communication ic tag, information transmission medium and radio communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio communication for improving sheet which improves communication distance that does not depend on attaching direction, and to provide a radio communication IC tag, an information transmission medium and a radio communication system.SOLUTION: A first spacer 2 includes an arrangement surface 2a, to which a radio IC tag is attached and to the other surface which is opposite to the arrangement surface 2a of the first spacer 2, and an auxiliary antenna 3 which resonates to waves used for radio communication is attached. A second spacer 4 is arranged in the opposite side to the first spacer 2, and the auxiliary antenna 3 is attached between the first and second spacers. The first spacer 2 and the auxiliary antenna 3 are provided with a hole S, the bottom of which is the second spacer 4. The shape of the auxiliary antenna 3 is square, and the length Lx of one edge along the x-axis of the auxiliary antenna is identical to the length Ly of the other edge along the y-axis.

Description

  INDUSTRIAL APPLICABILITY The present invention is used when a wireless communication IC tag is used, thereby improving a communication distance without depending on a reading direction, a wireless communication IC sheet, a wireless communication IC tag, an information transmission medium, a wireless communication The present invention relates to a communication system.

Wireless communication technology is applied not only in the field of information communication but also in the field of logistics management and the like. An IC tag for wireless communication (hereinafter simply referred to as “IC tag”) is an RFID (Radio Frequency).
It is widely known as a product that plays a part in Identification technology. Since the use of wireless communication devices for a variety of logistics management and inexpensive information storage media is diverse, wireless communication devices are placed in various usage environments.

  The IC tag is composed of an IC chip for storing data such as an identification number and an antenna for transmitting and receiving radio waves, and has a great advantage that it can be realized thinly and lightly.

  In order to make full use of such advantages, it is preferable that there is no restriction on the tag attachment position, and the tag is preferably communicable wherever and how it is attached.

  However, IC tags are designed to be used in free space, and when using radio waves in the ultra-high frequency band, ultra-high frequency band, and microwave band, general-purpose tags use a so-called dipole antenna to transmit and receive by radio communication. Therefore, if metal or the like is present in the vicinity of the antenna, the communication characteristics of the antenna deteriorate and the communicable distance is shortened.

  When a conductive material such as metal is present in the vicinity of the antenna, when a current flows through the antenna, a current in the opposite direction is induced on the metal side facing the antenna, and the input impedance of the antenna is greatly reduced by the induced current. . As a result, impedance cannot be matched with the IC chip designed for the environment in free space, and the communicable distance is shortened.

  In general, a dipole antenna, a monopole antenna, and a loop antenna generate a resonance current in an antenna by receiving radio waves of a specific frequency, and when this flows through an IC chip, it can be matched with the chip impedance in free space. Designed.

  If a conductive material exists in the vicinity of the antenna or IC chip, a current opposite to the current flowing through the antenna is induced on the surface of the conductive material, and each electric field on the surface of the conductive material facing the antenna is further reduced. A high part and a low part will be connected in high frequency, and a loop-shaped electric path will be generated via an antenna and a conductive material. The generation of this electric path significantly reduces the impedance of the antenna portion excluding the IC chip of the IC tag, so that it cannot be matched with the chip impedance, and the information signal cannot be transmitted. This shortens the communicable distance. In addition to metal, paper, glass, resin, liquid, and the like can be materials that degrade the communication characteristics of the IC tag.

  In the case of these materials, the resonance frequency of the antenna changes due to the dielectric properties and magnetism of these materials, and the communicable distance becomes shorter due to the difference between the frequency of the radio wave used by the communication partner and the resonance frequency of the antenna. .

  Patent Document 1 includes an IC tag body having an IC chip and an antenna unit, and is an IC tag fixed to an object, wherein a metal material is disposed on the object side of the IC tag body, and the IC tag body and An IC tag in which a metal material is covered with a covering member is disclosed.

JP 2009-48550 A

  The wireless communication improving sheet described in Patent Document 1 can prevent deterioration of the communication distance even if it is attached to an object containing metal or liquid, but the communication distance cannot be improved depending on the attaching direction.

  When using for the purpose of physical distribution management, the wireless communication improvement sheet body with IC tag is pasted on the side of the case for transporting the product, and when the reader passes through the gate provided with the reader for reading The IC tag is read by.

  Here, the electric field direction of the radio wave for reading emitted from the reader (direction perpendicular to the propagation (traveling) direction of the radio wave) and the resonance direction of the wireless communication improving sheet body on which the IC tag is arranged (mainly the longitudinal direction of the antenna) Is attached to the side of the case in a parallel orientation, wireless communication is sufficiently possible, but if it is attached to the side of the case so as to be orthogonal, the reader and the IC tag are wireless Communication is not possible.

  Furthermore, generally circularly polarized waves are used as radiated radio waves from the reader in order to suppress the polarization dependence. As a result, when radio waves are received in space, stable reading can be obtained without depending on the direction of the receiving antenna. However, even in this case, the situation changes if there is a metal object near the IC tag (receiving antenna). When a metal surface exists in a space where radio waves propagate, if a stable radio wave (referred to as a “plane wave” with the same magnitude of the electric field and magnetic field) comes as a far field, its direction, electric field distribution, The magnetic field distribution will be changed, and the positional relationship of the IC tag attached so as to be read by the plane wave may be in a direction that cannot be read. Specifically, when approaching the metal surface, the electric field is distributed so as to be perpendicular to the metal surface, and the magnetic field may change its behavior so that it moves parallel to the metal surface, and the direction of the radio wave may align. . At this time, there are cases where the traveling direction of the electric field whose direction has been changed overlaps with the IC tag attaching direction (a direction parallel to the propagation (traveling) direction of radio waves), and in this case, reading may not be possible. In actual usage, when reading IC tags affixed to luggage loaded on metal pallets, metal forklifts, metal carts, etc., positions close to the metal material, metal braces, mesh, deck plates, etc. In some cases, the reading and writing of the IC tag affixed to the luggage loaded at the lower position close to the floor surface (such as a concrete floor surface) having radio wave reflectivity may occur.

  Accordingly, there is a problem that the IC tag cannot be read by the reader and the purpose of physical distribution management is not achieved.

  An object of the present invention is to provide a wireless communication improvement sheet body, a wireless communication IC tag, an information transmission medium, and a wireless communication system that can improve the communication distance without depending on the attaching direction.

The present invention is a wireless communication improvement sheet body that improves the wireless communication characteristics of the wireless IC tag by mounting the wireless IC tag,
An auxiliary antenna,
A first arrangement surface for arranging the wireless IC tag on a surface opposite to a surface on which the auxiliary antenna is provided without connecting the IC chip provided in the wireless IC tag and the auxiliary antenna. A spacer;
A second spacer provided on the opposite side of the first spacer across the auxiliary antenna,
The auxiliary antenna is provided with a hole or a notch, and a resonance part exhibiting omnidirectionality with respect to a radio wave having a communication frequency is provided.

  Further, the invention is characterized in that the shape of the resonance part is a square, a circle, a rectangle, or a shape including a combination of two sides having a predetermined angle and the sides having the same length, and an intersecting shape.

  Further, the invention is characterized in that the shape of the resonance part is a polygon having a curvature at at least one corner and an intersecting shape.

  In the invention, it is preferable that the auxiliary antenna includes one or a plurality of conductor layers, and at least one of the conductor layers is a resonance layer that resonates with an electromagnetic wave used for the wireless communication.

  Further, the present invention is characterized in that a back conductor layer is further provided on the opposite side of the second spacer from the auxiliary antenna, and the back conductor layer is the same as or larger than the conductor layer provided in the auxiliary antenna.

  Further, the present invention is characterized in that the hole or notch is provided so as to face at least an IC chip or a reactance loading portion included in the wireless IC tag when the wireless IC tag is mounted.

Further, the present invention is characterized in that a part or all of the outer surface is coated with a dielectric material.
Further, the invention is characterized in that at least one of the arrangement surface and the surface opposite to the arrangement surface has adhesiveness or adhesiveness.

The present invention also provides the wireless communication improvement sheet body,
A wireless communication IC tag comprising: an omnidirectional wireless IC tag arranged on a placement surface of the wireless communication improvement sheet body; or an IC chip connected to the wireless communication improvement sheet body. .

  Further, the present invention is an information transmission medium in which the wireless communication improving sheet body or the wireless communication IC tag is incorporated.

  According to another aspect of the present invention, there is provided a wireless communication system using the wireless communication IC tag or the information transmission medium.

  According to the present invention, the wireless communication improving sheet body is capable of improving the wireless communication characteristics of the wireless IC tag by mounting the wireless IC tag.

  The wireless communication improving sheet body of the present invention can achieve improved communication without depending on the type of the article to be attached and the attaching direction of the wireless IC tag only by arranging a commercially available wireless IC tag. The exchange of radio signals between the auxiliary antenna and the IC chip of the wireless IC tag does not use processes such as lead wiring, wiring, and soldering, but only through the electromagnetic field distribution in the space. Resonance frequency adjustment can be realized.

  The first spacer has a placement surface for placing the wireless IC tag on the surface opposite to the surface on which the auxiliary antenna is provided, and on the opposite side of the first spacer with the auxiliary antenna interposed therebetween. A second spacer is provided.

The auxiliary antenna is provided with a hole or a notch.
As a result, the dipole antenna of the wireless IC tag and the auxiliary antenna are electromagnetically coupled through the hole or notch, and the communication improvement effect by the auxiliary antenna is exhibited.

  Further, the auxiliary antenna is provided with a resonance portion that exhibits non-directionality with respect to a radio wave having a communication frequency. Since the auxiliary antenna has such a resonance part, the wireless IC tag is configured such that the electric field direction of the radio wave for reading irradiated from the reader is orthogonal to the resonance direction of the wireless communication improving sheet body in which the wireless IC tag is arranged. Even if it is affixed to the product in any direction, wireless communication is possible, and the communication distance can be improved without depending on the affixing direction.

  Further, according to the present invention, the shape of the resonance part is a square, a circle, a rectangle, or a shape including a combination of two sides having a predetermined angle and an equal side length, and a cross shape. The communication distance can be improved without depending on the attaching direction.

  Further, according to the present invention, the shape of the resonance part is a shape having a curvature at at least one corner and an intersecting shape, so that the Q value can be lowered and the resonance part is widened. As a result, the communication distance can be further improved without depending on the attaching direction.

  According to the present invention, the auxiliary antenna includes one or a plurality of conductor layers, and at least one of the conductor layers resonates with the electromagnetic wave used for the wireless communication, so that the wireless communication by the auxiliary antenna can be performed. It becomes possible, and the communication improvement effect is exhibited.

  According to the invention, the back conductor layer is provided on the opposite side of the second spacer from the auxiliary antenna, and the back conductor layer is made larger than the conductor layer provided in the auxiliary antenna. Thereby, the influence of the position and material of the abutment to which the wireless communication improving sheet body is attached can be reduced more reliably, and the directivity of the transmission radio wave can be improved.

  According to the invention, the hole or notch is provided so as to face at least an IC chip or a reactance loading portion provided in the wireless IC tag when the wireless IC tag is mounted.

  Thereby, the influence which an auxiliary antenna gives as a conductor material can be made small, and the communication improvement effect can be improved further.

  In addition, according to the present invention, by covering a part or all of the outer surface with a dielectric material, the influence of unnecessary electromagnetic waves from the outside and the influence from the surrounding environment can be reduced, and the communication improvement effect can be further improved. it can.

  According to the present invention, at least one of the arrangement surface and the surface opposite to the arrangement surface is provided with adhesiveness or adhesiveness, so that the wireless IC tag can be mounted or applied to a target product. Pasting can be performed easily.

  Further, according to the present invention, the wireless IC improvement sheet body is integrated with the wireless IC tag by mounting the wireless IC tag on the arrangement surface of the wireless communication improvement sheet body. Regardless, wireless communication can be performed. Further, the IC chip can be directly and directly attached to the wireless communication improving sheet body, whereby the size can be further simplified.

  According to the present invention, there is provided an information transmission medium incorporating the wireless communication improving sheet body or the wireless communication IC tag.

The information transmission medium is, for example, a slip, a certificate, a card, or a label.
Products, intermediate products, parts, materials, containers made of these materials, containers, transporters, or transportation means, such as slips, certificates, cards, labels, etc. Even if it is directly attached as an information transmission medium, wireless IC tag communication can be performed.

  Further, according to the present invention, by using the above-described wireless communication IC tag or the above information transmission medium, it is possible to realize a wireless communication system in which reading and writing errors and reading and writing failures do not occur.

It is a top view of sheet 1 which is a 1st embodiment of the present invention. 1 is a cross-sectional view of a sheet body 1. It is a top view of the sheet | seat body 1a which is 2nd Embodiment of this invention. FIG. 2 is a plan view of a wireless communication IC tag 30 in which a wireless IC tag 20 is disposed on a sheet body 1. It is a top view of IC tag 30a for radio | wireless communication which has arrange | positioned the radio | wireless IC tag 20 to the sheet | seat body 1a. It is sectional drawing of the sheet | seat body 11 which is other embodiment of this invention. It is a top view which shows the sheet | seat body 24 which is further another embodiment of this invention. 3 is a cross-sectional view showing a configuration of a wireless communication IC tag 30 covered with a covering layer 6. FIG. 1 is a diagram illustrating an example of a wireless communication system 40. FIG. It is a graph which shows the frequency characteristic of the minimum starting electric power only of a wireless IC tag. It is a graph which shows the frequency characteristic of the minimum starting electric power of Examples 1-3. 6 is a graph showing frequency characteristics of minimum starting power of Comparative Example 1;

  The present invention is a wireless communication improving sheet body (hereinafter simply referred to as “sheet body”) that can improve the wireless communication characteristics of the wireless IC tag without depending on the reading direction by mounting the wireless IC tag. It is.

  The sheet body of the present invention is for disposing a wireless IC tag on the surface opposite to the surface on which the auxiliary antenna is provided without connecting the IC chip provided to the wireless IC tag and the auxiliary antenna. A first spacer having an arrangement surface and a second spacer provided on the opposite side of the first spacer across the auxiliary antenna are stacked, and the auxiliary antenna is provided with a hole or a notch, and communication A resonance portion that exhibits non-directionality with respect to a radio wave having a frequency is provided.

  In the prior art, even if an attempt is made to read information from a wireless IC tag in a state where the resonance direction of the sheet body on which the wireless IC tag is arranged and the electric field direction of the radio wave for reading irradiated from the reader are orthogonal, Cannot read.

  In order to eliminate such a problem, the sheet body of the present invention is provided with a resonance portion that exhibits omnidirectionality with respect to a radio wave having a communication frequency used for wireless communication as the shape of the auxiliary antenna.

  Examples of the shape of the auxiliary antenna having such a resonance part include a square, a circle, a regular octagon, and a cross. Moreover, since it is sufficient if it is a resonance part, the structure which has a concave notch and a convex part in a rectangular side may be sufficient. More specifically, when an orthogonal x-axis and y-axis are assumed on a virtual plane perpendicular to the thickness direction of the auxiliary antenna, the length Lx of one edge along the x-axis of the auxiliary antenna and the other along the y-axis It suffices that the length Ly of the edge of the lens is substantially equal. It should be noted that the two edges do not necessarily need to be orthogonal to each other as long as they are auxiliary antennas provided in a shape such that two sides having the same side length form a predetermined angle. The predetermined angle is, for example, 60 ° to 120 °. Further, the lengths Lx and Ly of the two sides may be the same dimension or substantially the same dimension, and the shape of the other part is not limited. Further, Lx and Ly need only have at least one pair of sides having the same size or substantially the same size, and even if there are other sides, they do not necessarily have the same size. Such a side-to-side relationship is the same not only in the shape of the auxiliary antenna but also in the shape of the hole or notch.

  Here, the function of improving the wireless communication characteristics by the hole or notch (slit or slot) provided in the auxiliary antenna will be described.

  The antenna of the wireless IC tag and the auxiliary antenna are coupled through a hole or a notch, and wireless communication by the auxiliary antenna becomes possible. As a result, the communicable distance can be improved.

  When a wireless IC tag composed of a general-purpose IC chip and a long-axis antenna element (including a meander shape) is attached to a sheet body, a hole or notch is provided in the auxiliary antenna to respond to the resonance operation of the antenna. The electric field generated in the wireless IC tag is reflected in the hole or notch provided in the auxiliary antenna along the direction recognized as the major axis direction as a whole shape of the antenna arranged facing the hole or notch, Since an electric field is generated, electromagnetic coupling between the antenna (and the IC chip) and the auxiliary antenna is activated through the electric field. The electric field generated in the hole or notch provided in the auxiliary antenna is generated by reflecting the direction of the electric field generated in the wireless IC tag rather than resonance in the hole or notch provided in the auxiliary antenna. As a result, anisotropy corresponding to the radio wave reception direction of the wireless IC tag appears. Furthermore, the hole or notch can suppress the induced current corresponding to the antenna generated in the conductor plate.

  The auxiliary antenna of the present invention is configured to resonate with a radio communication frequency as a whole when combined with a wireless IC tag, and the resonance layer of the auxiliary antenna has a resonance part of The dimension is in the range of λ / 8 to 3λ / 4.

  The sheet body of the present invention can improve the communication of the wireless IC tag by simply placing the wireless IC tag on the placement surface of the wireless IC tag without connecting the IC chip of the wireless IC tag and the auxiliary antenna. Commercially available wireless IC tags have different chip impedance values depending on their designs. This impedance differs depending on whether it is stationary or in operation, and varies depending on the amount of energy received even under operating conditions. A feature of the wireless communication improvement sheet of the present invention is that impedance matching and improvement can be realized simply by pasting on these wireless IC tags having unstable and variable impedance. The wireless communication improvement sheet body of the present invention can obtain the wireless communication improvement effect by the impedance adjustment function by the auxiliary antenna.

  With such a feature, even if a communication obstruction member such as metal, paper, glass, resin, liquid, etc. is present in the vicinity of the wireless IC tag, the wireless communication improving sheet body of the present invention can be used to achieve good and stable wireless communication. Communication characteristics can be obtained.

  Furthermore, by providing a resonance part that exhibits non-directionality with respect to radio waves of the communication frequency in the auxiliary antenna, even when it has been impossible to read or write by a reader in the past, reading and writing of a wireless IC tag is possible. Can be performed.

Below, the sheet | seat body of this invention is demonstrated in detail using drawing.
FIG. 1 is a plan view of a sheet body 1 according to the first embodiment of the present invention, and FIG. 2 is a cross-sectional view of the sheet body 1.

  The sheet body 1 includes a first spacer 2, an auxiliary antenna 3, a second spacer 4, and a back conductor layer 5. The shape of the auxiliary antenna 3, that is, the outer shape of the sheet body 1 is a square, and the first spacer 2. The auxiliary antenna 3 is provided with a hole S having a square opening shape.

  The first spacer 2 has an arrangement surface 2a on which the wireless IC tag is arranged when the sheet body is used. The first spacer 2 is provided so that the surface opposite to the arrangement surface 2a is in contact with the auxiliary antenna 3, and the wireless IC The dielectric layer is configured to insulate between the dipole antenna of the tag and the auxiliary antenna 3.

  The auxiliary antenna 3 resonates at the communication frequency of the wireless IC tag, thereby electromagnetically coupling with the dipole antenna of the wireless IC tag, and functions as a resonant antenna.

  The second spacer 4 is provided on the side opposite to the first spacer with the auxiliary antenna 3 interposed therebetween, and is configured of a dielectric layer that insulates between the auxiliary antenna 3 and the back conductor layer 5.

  The back conductor layer 5 is provided on the opposite side of the second spacer 4 from the auxiliary antenna 3 and functions as a ground layer.

  The first spacer 2, the auxiliary antenna 3, the second spacer 4, and the back conductor layer 5 have the same outer dimensions, and are laminated in this order to constitute the sheet body 1.

  The planar shape when the sheet body 1 is viewed from the stacking direction is preferably a shape including a combination of two sides that form a predetermined angle and have the same side length. The angle formed by these two sides is preferably 90 °, but does not have to be strictly 90 °. If the angle is within a range of 60 ° to 120 °, which can be called substantially vertical, different reading and writing are possible. The effect of reducing the directivity is recognized. Further, the auxiliary antenna 3 has the same shape, and each edge of the outer shape becomes a resonance part corresponding to the radio wave of the communication frequency. By forming the auxiliary antenna 3 in such a shape, the electric field direction of the radio wave for reading emitted from the reader (direction perpendicular to the propagation (traveling) direction of the radio wave) and the wireless communication improving sheet body in which the wireless IC tag is arranged Even in a state where the resonance directions of the two are orthogonal, wireless communication between the reader and the wireless IC tag is possible, and information can be read from the IC tag arranged on the sheet body 1.

Moreover, the total thickness of the sheet | seat body 1 is about 0.5-10 mm.
In 1st Embodiment, the planar shape of the sheet | seat body 1 is a square, and the square hole S is provided in the center part. The position of the hole S is not necessarily the central portion of the sheet body 1. It can be set as appropriate according to the position of the IC chip of the wireless IC tag, the joint portion thereof, and the reactance loading portion.

  As shown in the cross-sectional view of FIG. 2, the hole S is configured to penetrate the first spacer 2 and the auxiliary antenna 3 in the stacking direction, and the second spacer 4 forms the bottom of the hole. Accordingly, the depth D of the hole S is the same as the sum of the thickness of the first spacer 2 and the thickness of the auxiliary antenna 3, and is, for example, 0.1 to 5 mm.

  The length L of one side of the hole S is formed to be 5 to 95% with respect to the length L0 of one side of the sheet body 1.

  By providing such a hole S, the dipole antenna of the wireless IC tag arranged on the arrangement surface 2a and the auxiliary antenna 3 are electromagnetically coupled through the hole S, and the auxiliary antenna 3 serves as a resonance antenna. Function. Furthermore, since the hole S is provided immediately below the wireless IC tag, the influence of the auxiliary antenna 3 as a conductor on the IC chip can be reduced.

  FIG. 3 shows another example of the opening shape of the hole S. The shapes shown in these drawings are shapes having at least one pair of sides having the same dimensions orthogonal to each other when viewed from the front side of the drawing. Further, the one set of sides does not need to be connected to each other, and may be any two sides of the sides of the hole S. Further, the hole S may have a plurality of such combinations of sides, and may further intersect. As long as the shape of the hole S has a set of sides that satisfy such a relationship, the size and shape of the remaining sides and portions are not limited, and may be indefinite or curved. Shape, straight line shape, polygonal line shape, arc shape, or the like. Although the hole S may be involved in resonance, it is not always necessary to participate in the hole S, and it is sufficient to satisfy the functions of electromagnetic coupling and impedance matching. The same applies to not only the hole S but also the notch.

  The non-directional resonance part referred to in the present invention is the one that the auxiliary antenna 3 has, but the part may exist as the outer shape of the auxiliary antenna 3 or the outer shape of the hole S. . Furthermore, each side may exist individually in the auxiliary antenna 3 and the hole S. It is necessary to have a shape capable of receiving and transmitting so as to reduce directivity at the resonance part. In order to improve the communication distance without depending on the attaching direction, it is effective to adopt a circular shape or a shape in which at least one corner of the polygon has a curvature. This is because the resonance current when radio waves are received flows smoothly due to these shapes, and the area that can be received without depending strongly on the direction of the incoming radio waves is widened.

  As described above, by disposing the wireless IC tag on the sheet member 1, wireless communication between the reader and the wireless IC tag can be performed regardless of the attachment location and attachment direction of the wireless IC tag.

  The first spacer 2 and the second spacer 4 insulate the wireless IC tag and the auxiliary antenna 3 from each other, insulate the auxiliary antenna 3 and the back surface conductor layer 5 from each other, and serve as a dielectric layer to influence the wavelength shortening effect. By giving, the resonance frequency of the auxiliary antenna 3 is adjusted. In some cases, a portion where the electric field = 0 is formed between the auxiliary antenna 3 and the back surface conductor layer 5. In this case, the auxiliary antenna 3 and the back surface conductor layer 5 are electrically connected to each other by providing a via in the portion where the electric field = 0. Operation is possible even if it is made to do.

  If the first spacer 2 and the second spacer 4 can maintain the positional relationship between the wireless IC tag and the auxiliary antenna 3 or the back conductor layer 5, the loss of electromagnetic energy is low, that is, the dielectric loss tangent in the communication frequency band. It is preferable to use a material having a low tan δ (ε ″ / ε ′) or magnetic tangent tan δ (μ ″ / μ ′). For example, it may be a space, but generally an organic material as exemplified below is used. As the first spacer 2, a base material (such as resin, paper, or inorganic material) that is a constituent member of the wireless IC tag can be used as it is. It is also possible to use the adhesive layer of the wireless IC tag.

  Examples of the organic material include porous bodies such as high molecular organic materials such as rubber, thermoplastic elastomer, various plastics, wood, and paper. Examples of the rubber include natural rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, ethylene-propylene rubber, ethylene-propylene rubber, ethylene-propylene-diene rubber (EPDM rubber), ethylene-vinyl acetate rubber, butyl rubber, Synthetic rubber alone such as halogenated butyl rubber, chloroprene rubber, nitrile rubber, acrylic rubber, ethylene acrylic rubber, epichlorohydrin rubber, fluorine rubber, urethane rubber, silicon rubber, chlorinated polyethylene rubber, hydrogenated nitrile rubber (HNBR), These derivatives or those modified by various modification treatments can be mentioned. These rubbers can be used alone or in combination.

  Examples of thermoplastic elastomers include chlorinated polyethylenes such as chlorinated polyethylene, ethylene copolymers, acrylics, ethylene acrylic copolymers, urethanes, esters, silicones, styrenes, amides, olefins, etc. Various thermoplastic elastomers and their derivatives are mentioned.

  Further, various plastics include, for example, chlorine resins such as polyethylene, polypropylene, AS resin, ABS resin, polystyrene, polyvinyl chloride, and polyvinylidene chloride; polyvinyl acetate, ethylene-vinyl acetate copolymer, fluororesin, and silicone resin. , Thermoplastic resins such as acrylic resin, nylon, polycarbonate, polyethylene terephthalate, alkyd resin, unsaturated polyester, polysulfone, polyimide resin, urethane resin, phenol resin, urea resin, epoxy resin, etc. and these Derivatives, further copolymers and recycled resins are exemplified.

  As each spacer, the above dielectric material can be used as it is, or it can be combined and modified, and a material with reduced density is more preferable. Each spacer can be used in a state where various chemicals, additives, reinforcing agents, plasticizers, oils, extenders, curing agents, and the like are blended with the above materials.

The dielectric material constituting the first spacer 2 and the second spacer 4 preferably has a density of less than 1.0 g / cm ³ , for example.

  As such a low-density dielectric material, one or more materials selected from a porous organic material and a porous inorganic material are used. A material that does not foam may be used, or a material that does not foam may be combined with a foamed material. A typical low density dielectric material is a foamed resin such as a styrofoam resin. In addition to these, paper materials such as cardboard, wood, glass, glass fiber, and earth-based materials can also be used. It is also possible to use the base material and adhesive layer of the wireless IC tag as the spacer material.

  Although the foaming method of the foam material is not limited, methods such as adding a foaming agent or adding thermally expandable fine particles can be used. As the foaming agent, either an organic foaming agent or an inorganic foaming agent may be used.

  As the organic foaming agent, for example, dinitrosopentamethylenetetramine (DPT), azodicarbonamide (ADCA), p, p′-oxybisbenzenesulfonylhydrazide (OBSH), hydrazide dicarbonamide (HDCA) and the like can be added. It is not limited to these.

  As the inorganic foaming agent, sodium hydrogen carbonate or the like can be added, but is not limited thereto, and can be appropriately selected and added depending on the material.

  Further, as the thermally expandable fine particles, microencapsulated thermally expandable fine particle spheres and the like can be added.

  Although the foaming rate is not particularly limited, it is necessary to have a form in which the thickness change of the spacer is small, the strength is maintained, and the weight can be reduced. For these reasons, the foaming rate is preferably about 2 to 30 times.

  The foam structure is not particularly limited, but a structure that is strong in the compression direction, for example, a foam structure that is flatly foamed in the thickness direction is preferable.

  The wood is a woody material such as plywood, lauan material, particle board, MDF, etc., and is not essentially limited by the material, and a plurality of materials can be used in combination.

  Examples of the porous inorganic material include, but are not limited to, various ceramic materials, gypsum board, concrete, foamed glass, pumice, asphalt, and earth materials.

  As the first spacer 2 and the second spacer 4 need to change the received radio wave energy to transmission energy with as little loss as possible, it is necessary to select one having a small energy loss due to the material used. For this purpose, the dielectric loss tangent tan δ (ε ″ / ε ′) is preferably 0.5 or less, more preferably 0.2 or less, at the frequency of the radio wave used by the wireless IC tag for wireless communication.

  As a material of the spacer, it is preferable to combine both low density and low dielectric loss tangent tan δ (ε ″ / ε ′) as described above, but more importantly, low dielectric loss tangent tan δ in the communication frequency band (UHF band or the like). It is to have.

  Further, if the real part ε ′ of the complex relative permittivity is high, the sheet size can be reduced and the size can be reduced. Therefore, ε ′ is preferably 1 to 50. However, since the characteristics of the sheet body change depending on various parameters, the present invention is not limited to this numerical range.

  The first spacer 2 and the second spacer 4 may be made of different dielectric materials, or may be made of the same dielectric material. An adhesive, an adhesive, or the like for bonding may be used as it is as the second spacer.

The auxiliary antenna 3 and the back conductor layer 5 are made of a conductive material having conductivity.
The conductive material may be a metal such as gold, platinum, silver, nickel, chromium, aluminum, copper, zinc, lead, tungsten, or iron, and the metal powder or conductive carbon black is mixed in the resin. It may be a resin mixture or a conductive resin film. The metal or the like may be processed into a foil shape, a plate shape, a sheet shape, a film shape, or the like. Alternatively, a thin metal layer having a thickness of, for example, 600 mm may be formed on the surface of the synthetic resin film. What transferred metal foil to base materials, such as a film or cloth, may be used. Also, carbon-based particles, carbon-based fibers, metal particles, metal fibers, metal oxide-based conductive ink and conductive patterns (for example, resistivity 10Ω / □ or less) are applied to the surfaces of the first spacer 2 and the second spacer 4. It may be applied or formed.

  The hole or notch can be formed by a general forming method. In the first spacer 2, a predetermined part that becomes a hole or a notch is removed from a plate-like member made of a dielectric material by using mechanical processing such as punching or cutting, or chemical processing such as etching. That's fine. Further, depending on the dielectric material used, it is possible to mold into a shape in which holes or notches are provided in advance at the time of molding.

  Similarly to the first spacer 2, the auxiliary antenna 3 may be mechanically or chemically processed to remove a predetermined portion that becomes a hole or notch. It is also possible to directly print, vapor-deposit, and apply on the spacer so as to have a shape provided with a notch in advance.

  A hole or a notch may be formed in each of the first spacer 2 and the auxiliary antenna 3 by using the method described above, and the auxiliary antenna 3 is laminated on the first spacer 2 in advance. At the same time, holes or notches may be formed.

  The hole or notch is indispensable in the auxiliary antenna 3, but it may not be provided in the back conductor layer 5. Similarly, in the first spacer 2 and the second spacer 4, holes or notches are provided. Need not be provided. It is important to provide a hole or notch in the conductor layer closest to the IC tag, that is, the auxiliary antenna 3.

  The shape of the hole S is not limited to the slot shape as in the first embodiment, but may be a notch shape (slit shape) as long as the opening shape has a non-directional resonance part. In the case of the notch shape, if the opening shape is a square, it may be formed so that one of the four sides is opened. Further, the auxiliary antenna 3 may be divided into a plurality of conductor layers in a planar shape, and a gap portion between the divided conductor layers may be a hole or a notch.

  Note that the dimension of one side of the hole, notch, or gap may be a dimension that resonates with the frequency of the radio wave used for wireless communication, or a dimension that does not resonate.

  FIG. 3 is a plan view of a sheet body 1a according to the second embodiment of the present invention. The second embodiment differs from the first embodiment only in the shape of the provided holes, and the materials constituting each layer are the same as those in the first embodiment, so only the shape of the holes will be described below. .

  In the second embodiment, similarly to the first embodiment, the planar shape of the sheet body 1a, that is, the shape of the auxiliary antenna 3 is a square, and a hole S1 having an opening in a cross shape is provided at the center. As described above, the cross shape is also a shape that becomes an omnidirectional resonance part like a square, and by having such an opening shape, the auxiliary antenna 3 and the hole S1 have omnidirectionality, and are attached. The communication distance can be improved without depending on the attaching direction.

  The cross section of the hole S1 is the same as the cross section shown in FIG. 2 in the first embodiment, and penetrates the first spacer 2 and the auxiliary antenna 3 in the stacking direction. As a result, the second spacer 4 becomes the bottom of the groove. It is the structure which forms.

  The depth D of the hole S1 is the same as the sum of the thickness of the first spacer 2 and the thickness of the auxiliary antenna 3, and is, for example, 0.1 to 5 mm. The width W1 of the hole S1 is, for example, 10 to 60 mm, although it depends on the size of the IC chip, the joint portion thereof, and the reactance loading portion.

  By providing such a hole S1, the dipole antenna or IC chip of the wireless IC tag arranged on the arrangement surface 2a and the auxiliary antenna 3 are electromagnetically coupled through the hole S1, and the auxiliary antenna 3 is Functions as a resonant antenna. Furthermore, since the hole S1 is provided immediately below the wireless IC tag, the influence of the auxiliary antenna 3 as a conductor on the IC chip and the loop portion (reactance loading portion) can be reduced.

  FIG. 4 is a plan view of the wireless communication IC tag 30 in which the wireless IC tag 20 is arranged on the sheet body 1. FIG. 5 is a plan view of a wireless communication IC tag 30a in which the wireless IC tag 20 is arranged on the sheet body 1a.

  As described above, the wireless IC tag 20 is arranged on the arrangement surface 2a of the first spacer 2 of the sheet body 1 or 1a without being connected to the sheet body 1 or 1a. Arrangement without connection means that the auxiliary antenna 3 of the sheet body 1, 1 a and the wireless IC tag 20 are not directly connected (DC coupled) by a conductor wiring or the like, but the arrangement of the first spacer 2. The wireless IC tag 20 is simply placed on the surface 2a.

  The wireless IC tag 20 includes an IC chip 21 that stores ID information, and an antenna 22 that is connected to the IC chip 21 and receives radio waves from the reader and transmits radio waves to the reader. It is formed on a film substrate such as a film by foil transfer, vapor deposition, printing or the like.

  The wireless IC tag 20 is arranged so that the IC chip 21 faces the hole S or the hole S1 provided in the auxiliary antenna 3 as shown in FIGS.

  The wireless IC tag 20 shown in FIGS. 4 and 5 is a so-called omnidirectional wireless IC tag that does not have directivity in the communication direction in which the antenna 22 is formed in a substantially cross shape. Such a non-directional wireless IC tag 20 is preferable as the wireless IC tag arranged on the sheet bodies 1 and 1a, but a directional wireless IC tag whose antenna extends in one direction may be used. In the wireless IC tag of the present invention, the wireless IC tag, the auxiliary antenna, and possibly the hole or notch also have a resonance function. The main resonance function as an antenna is an auxiliary antenna. However, since a wireless IC tag, a hole, or a notch can also compensate for resonance, it is most preferable that each resonance part has omnidirectionality. However, in order to reduce directivity (this is referred to as non-directivity in the present invention), it is not necessary for all to resonate at the same time, and at least one of the portions only needs to resonate.

  FIG. 6 is a cross-sectional view of a sheet body 11 which is another embodiment of the present invention. In the above embodiment, the configuration in which the hole S or the hole S1 with the second spacer 4 as the bottom is provided in the first spacer 2 and the auxiliary antenna 3 has been described. However, as in the present embodiment, the first spacer 2 is provided. May be configured such that a hole, a notch, or a gap is provided only in the auxiliary antenna 3 without providing a hole or a notch.

  As a manufacturing method of the present embodiment, the first spacer 2 that is not provided with a hole or notch may be attached to the auxiliary antenna 3 provided with a hole, a notch, or a gap. After the first spacer 2 and the auxiliary antenna 3 are provided with holes, notches, or gaps, they may be filled.

FIG. 7 is a plan view showing a sheet member 24 according to still another embodiment of the present invention.
In the sheet body 24 of the present embodiment, the size of the back conductor layer 5 is formed larger than the size of the auxiliary antenna 3. Accordingly, as shown in the plan view of FIG. 7, the back conductor layer 5 is provided so as to protrude outward. By projecting the back conductor layer 5 outward, the directivity of the transmission radio wave can be increased, and the communication improvement effect is improved.

  FIG. 7A shows an aspect in which the back conductor layer 5 protrudes over the entire periphery of the auxiliary antenna 3, and FIG. 7B shows the same as each side from each of the four sides of the auxiliary antenna 3. The aspect which protruded in the direction orthogonal to a side by the width | variety is shown.

FIG. 8 is a cross-sectional view showing the configuration of the wireless communication IC tag 30 covered with the covering layer 6.
The wireless communication IC tag 30 according to this embodiment is configured such that the wireless IC tag 20 is disposed on the arrangement surface 2 a of the sheet body 1 and is covered with the coating layer 6.

  The dielectric material used for the coating layer 6 has a dielectric loss tangent tan δ (953 MHz) of 0.2 or less. When the covering layer 6 is formed using a dielectric material having tan δ greater than 0.2, the communicable distance of the wireless IC tag 20 is shortened by molding the covering layer 6. This is presumably because energy loss occurs when radio waves transmitted and received by the wireless IC tag 20 pass through the covering layer 6, and the communicable distance is shortened. Further, as the dielectric material, it is preferable that the real part ε ′ (953 MHz) of the complex relative dielectric constant is 1.0 to 50 in order to reduce the thickness of the coating layer 6.

  Suitable dielectric materials for such a covering layer 6 include EVA (ethylene-vinyl acetate copolymer) resin, PET (polyethylene terephthalate) resin, polycarbonate resin, polyethylene resin, polypropylene resin and the like. The EVA resin has a tan δ (953 MHz) of 0.01 and an ε ′ (953 MHz) of 2.39. The PET resin has a tan δ (953 MHz) of 0.01 and an ε ′ (953 MHz) of 2.9.

  Coating of the sheet 1 and the wireless IC tag 20 with the coating layer 6 can be performed using a known welding technique. The welding is performed by a method in which the temperature of the member is raised, impulse welding, hot plate welding, high frequency welding, ultrasonic waves. There is welding. In addition, an injection molding method, a compression molding method, a transfer molding method, a casting method, a dipping method, a dipping method, and other appropriate molding methods can be used.

  By mounting the wireless IC tag on the sheet body 1 of the present invention, even if it is attached to a material that is a communication blocking member such as a conductive material, a dielectric material, a magnetic material, or even if the orientation of the wireless IC tag is rotated, As in the case of free space, the wireless communication IC tag has good wireless communication characteristics by the radio wave method.

  Although the communication frequency used as object by this invention is not specifically limited, Arbitrary single | single or several frequency can be selected including the range of 300 MHz or more and 300 GHz or less. The range of 300 MHz to 300 GHz includes UHF band (300 MHz to 3 GHz), SHF band (3 GHz to 30 GHz), and EHF band (30 GHz to 300 GHz). In addition, mounting the wireless IC tag on the sheet body 1 of the present invention is a wireless communication improvement measure for an antenna that performs radio wave communication at the above frequency.

  An information transmission medium such as a slip, a certificate, a card, or a label incorporating the sheet body or the wireless communication IC tag of the present invention can be used. These vouchers are still used in logistics, logistics, distribution, inventory management, process management, etc. as work instructions, requests, purchase orders, delivery slips, bills, slips, management tables, kanbans, etc. However, when a general-purpose wireless IC tag is incorporated or pasted as in the past, it cannot be pasted on the communication disturbing member. However, in the actual manufacturing industry, there are a large number of materials and materials made of communication blocking members around the environment where IC tags are used. By using the sheet body or the wireless communication IC tag of the present invention, products, intermediate products, parts, materials and the like made of metal or conductive or communication blocking members such as materials having a high dielectric constant As signboards, slips, certificates, cards, or labels on containers made of materials, materials, containers, pallets, cars, forklifts, containers, bags, sachets, cases, returnable boxes, conductive boxes, components, components, etc. It is possible to perform wireless IC tag communication regardless of the direct attachment and the attachment direction. As a result, the target products in distribution management, inventory management, distribution management, information management, etc. are expanded, and product or article management becomes easy.

  Yet another embodiment of the present invention is a wireless communication system. As shown in FIG. 9, for example, as shown in FIG. 9, wireless IC tags 30 are attached to a plurality of metal containers 31, respectively, and these are collectively passed through an antenna gate unit 41 provided with a reader 42. An RFID radio communication system 40 that performs reading and writing can be cited. In addition, wireless IC tags 30 are affixed to a large number of metal articles, and they are sequentially flowed on a conveyor (with a certain interval between them), and they are distributed and managed (in / out of goods) at an antenna gate portion installed at an arbitrary place. RFID) communication system that performs management) and traceability management can be configured. As information to be transmitted, not only product ID but also history information and special mention information can be used as work instructions, request forms, delivery slips, purchase orders, etc., for example, inventory management and cost management data It can also be expected to improve productivity such as yield improvement and cost reduction.

Examples of the present invention will be described below.
As an example, a sheet body 1 provided with a hole S having a square opening shape shown in FIG. 1 was produced, and three types of wireless IC tags were attached to the sheet body 1 to produce a wireless communication IC tag.

  The sheet body 1 was a square having a side length of 120 mm. As the first spacer 2, a PET (polyethylene terephthalate) film having a thickness of 0.1 mm was used. The auxiliary antenna 3 is an aluminum foil layer having a thickness of 0.05 mm. The hole S has a square opening shape, and the length L of one side of the opening is 50 mm. As the second spacer 4, a foam material having a thickness of 4 mm (foaming ratio 5 times) was used. The arrangement position of the wireless IC tag is the central portion of the sheet body 1.

  In addition, as a comparative example, a sheet body having a configuration in which the auxiliary antenna does not have a resonance portion corresponding to radio waves having a communication frequency was manufactured. Specifically, one edge length Lx of the auxiliary antenna is set to 110 mm, and the other edge length Ly is set to 100 mm. The opening shape of the hole formed in the sheet body of the comparative example is a linear slot having a width of 10 mm and a length of 65 mm.

  The frequency characteristics of the minimum starting power were measured and used as the evaluation results. As measurement conditions, a wireless communication IC tag in which a wireless IC tag is arranged on a sheet body is attached to the surface of a metal plate, and the electric field direction of radio waves for reading emitted from the reader and the wireless communication improvement sheet in which the IC tag is arranged The measurement was performed under two conditions: a condition (condition A) in which the resonance direction of the body is parallel and a condition (condition B) perpendicular to the condition. The frequency characteristics of the minimum starting power were measured using an RFID tester (linearly polarized antenna, output 0 to 20 dBm) manufactured by Peritech Co., Ltd.

  In Example 1, an omnidirectional wireless IC tag (UPM, product name FROG) is arranged on the sheet body 1, and in Example 2, the first directional wireless IC tag (Alien, product name ALN-9540 is used). ) Was disposed on the sheet body 1, and in Example 3, a second directional wireless IC tag (trade name Short Dipole, manufactured by UPM) was disposed on the sheet body 1.

  In Comparative Example 1, a directional wireless IC tag (manufactured by Alien Co., Ltd., trade name: ALN-9540) was placed on the sheet body as described above.

  First, only three types of wireless IC tags were placed in free space, and the frequency characteristics of minimum starting power were measured. FIG. 10 is a graph showing the frequency characteristics of the minimum starting power of only the wireless IC tag. The horizontal axis represents frequency (MHz), and the vertical axis represents minimum starting power (dBm). The graph indicated by the solid line indicates the measurement result under the condition A, and the graph indicated by the dotted line indicates the measurement result under the condition B.

  FIG. 10A shows the measurement results when using the non-directional wireless IC tag, FIG. 10B shows the measurement results of the first directional wireless IC tag, and FIG. The measurement result of a 2nd directivity wireless IC tag is shown.

  The graph evaluates the ability to transmit a wireless signal defined by ISO to a wireless IC tag, activate the wireless IC tag, and return information stored in the IC chip (communication establishment). At this time, the smaller the minimum starting power, the longer the communicable distance, that is, the better the communication characteristics.

  As can be seen from the graph shown in FIG. 10, in the non-directional wireless IC tag, the frequency characteristics hardly change between the condition A and the condition B, and it was confirmed that the non-directional wireless IC tag is non-directional. In the first directional wireless IC tag and the second directional wireless IC tag, communication was possible in the condition A, but communication was not possible in the condition B. However, although the omnidirectional wireless IC tag can certainly be evaluated as omnidirectional, the minimum starting power value itself is high and the communication distance is not sufficient.

  Next, the frequency characteristics of the minimum starting power of Examples 1 to 3 and Comparative Example 1 were measured. FIG. 11 is a graph showing the frequency characteristics of the minimum startup power of Examples 1 to 3, and FIG. 12 is a graph showing the frequency characteristics of the minimum startup power of Comparative Example 1. The horizontal axis represents frequency (MHz), and the vertical axis represents minimum starting power (dBm). The graph indicated by the solid line indicates the measurement result under the condition A, and the graph indicated by the dotted line indicates the measurement result under the condition B.

  11A shows the measurement result of Example 1, FIG. 11B shows the measurement result of Example 2, and FIG. 11C shows the measurement result of Example 3.

  In Examples 1 to 3, both the condition A and the condition B are smaller than the case of only the wireless IC tag in the free space, although the minimum starting power is reduced and the condition is affixed to the surface of the metal plate. Communication distance was improved. In particular, in Examples 2 and 3, it was possible to communicate under Condition B, which could not be communicated at all even with a wireless IC tag even in free space, and the wireless communication characteristics were dramatically improved. Although the results of FIGS. 11 (a) to 11 (c) leave room for adjustment in the resonance frequency, the minimum starting power value is sufficiently low, respectively, from commercially available wireless IC tags (FIGS. 10 (a) to (c)). Has also declined significantly. This means that the communication distance is extended more than twice, and the communication characteristics can be improved at the same time as the directivity is reduced.

  In Comparative Example 1, the communication distance was improved under the condition A, but was not sufficiently improved under the condition B.

  In Comparative Example 1, the communication distance was not improved under Condition B, and in Examples 1 to 3, the communication distance was improved under Condition B. Therefore, the length Lx of one edge of the auxiliary antenna and the other edge It has been found that wireless communication can be performed regardless of the orientation of the wireless IC tag by using a square auxiliary antenna configured to have the same length Ly.

DESCRIPTION OF SYMBOLS 1,11 Sheet body 2 1st spacer 3 Auxiliary antenna 4 2nd spacer 5 Back surface conductor layer 6 Covering layer 20 Wireless IC tag 21 IC chip 22 Antenna 30 IC tag for wireless communication 40 Wireless communication system

Claims (11)

A wireless communication improvement sheet that improves wireless communication characteristics of a wireless IC tag by mounting the wireless IC tag,
An auxiliary antenna,
A first arrangement surface for arranging the wireless IC tag on a surface opposite to a surface on which the auxiliary antenna is provided without connecting the IC chip provided in the wireless IC tag and the auxiliary antenna. A spacer;
A second spacer provided on the opposite side of the first spacer across the auxiliary antenna,
A wireless communication improving sheet body, wherein the auxiliary antenna is provided with a hole or a notch and a resonance portion that exhibits non-directionality with respect to a radio wave having a communication frequency.   2. The radio according to claim 1, wherein the shape of the resonance part is a square, a circle, a rectangle, or a shape including a combination of two sides having a predetermined angle and an equal side length, and a cross shape. Communication improvement sheet body.   The wireless communication improvement sheet according to claim 1 or 2, wherein the shape of the resonance part is a polygon having a curvature at at least one corner and an intersecting shape.   The auxiliary antenna includes a single or a plurality of conductor layers, and at least one of the conductor layers is a resonance layer that resonates with a radio wave used for the wireless communication. The wireless communication improvement sheet | seat body as described in any one.   The backside conductor layer is further provided on the side opposite to the auxiliary antenna of the second spacer, and the backside conductor layer is the same as or larger than the conductor layer included in the auxiliary antenna. The wireless communication improvement sheet | seat body as described in any one.   The said hole or notch is provided so that it may oppose at least the IC chip or reactance loading part with which the said wireless IC tag is mounted when the said wireless IC tag is mounted. The wireless communication improvement sheet | seat body as described in any one.   7. The wireless communication improving sheet according to claim 1, wherein a part or all of the outer surface is coated with a dielectric material.   The wireless communication improving sheet body according to any one of 1 to 7, wherein at least one of the arrangement surface and the surface opposite to the arrangement surface has adhesiveness or adhesiveness. The wireless communication improvement sheet body according to any one of claims 1 to 8,
A wireless communication IC tag comprising: an omnidirectional wireless IC tag disposed on a surface of the wireless communication improving sheet body; or an IC chip connected to the wireless communication improving sheet body.   An information transmission medium comprising the wireless communication improving sheet according to any one of claims 1 to 8, or the wireless communication IC tag according to claim 9.   A wireless communication system using the wireless communication IC tag according to claim 9 or the information transmission medium according to claim 10.

Images