JP2020046838A - RF tag label - Google Patents

Abstract

To manufacture RF labels using UHF band at a low cost, and configure the RF tag labels to be compatible with a microwave oven.SOLUTION: An RF tag label 1 includes: a matching circuit 410 to which an IC chip 42 is connected; an inlay 4 formed by mounting an antenna 41 including two coupling elements 411 electrically connected to the matching circuit 410 on an inlay substrate 40; an auxiliary antenna sheet 2 having two conductive patterns 21 formed on one side using conductive ink; and an adhesive layer 3 laminated on a surface of the auxiliary antenna sheet 2 where the two conductive patterns 21 are formed. Each of the two conductive patterns 21 overlaps one of the coupling elements 411 via the adhesive layer 3, in a one-to-one relationship. In the RF tag label 1, the adhesive layer 3 is formed so that microwaves of a microwave oven passing through the adhesive layer 3 may be attenuated by 10% or more by use of aqueous adhesive.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an RF tag (RF: Radio Frequency) which is a medium used for wireless individual identification.

  2. Description of the Related Art An RF tag, which is a medium used for wireless individual identification, has been widely used in various fields such as manufacturing, distribution, retail, and service. As a frequency band of a carrier wave used by an RF tag, there is a 13.56 MHz band for performing communication using inductive coupling, but a UHF band for performing communication using an electromagnetic field because a relatively long communication distance can be obtained. (860-960 MHz) is widely used.

  An antenna corresponding to a frequency band of a carrier wave used by the RF tag label and an IC chip electrically connected to the antenna are mounted on the RF tag label in which the RF tag is formed in a seal label shape. Data used for managing an object to which the RF tag label is attached is stored in an IC chip that is electrically connected to the antenna.

  The type of antenna mounted on the RF tag label is determined according to the frequency band used by the RF tag label for communication as described in paragraph 0009 of Patent Document 1. In the case of an RF tag label that communicates using a 13.56 MHz band carrier, the antenna mounted on this RF tag label is a loop antenna, and in the case of an RF tag label that communicates using a UHF band carrier, this antenna is mounted on this RF tag label. The antenna to be used is generally a dipole antenna.

  In the case of a half-wave dipole antenna for the UHF band, the length of the antenna is about 16 cm. Therefore, two planar radiating elements are symmetrically arranged as in the invention disclosed in Patent Document 2. The use of a dipole antenna having the above-described structure to reduce the size of an RF tag label using the UHF band has become mainstream.

  The antenna disclosed in Patent Literature 2 has a dipole section having an effective length shorter than one half of the antenna resonance wavelength, a feed section provided at the center of the dipole section, and a center section surrounding the feed section. It has an inductance adjusting portion formed and both ends connected to a dipole portion, and an end portion provided at both ends of the dipole portion with a region wider than the line width of the dipole portion. This corresponds to the above-described radiating element.

JP-A-2006-343878 JP 2011-120303 A

  It is known that the communication performance of an RF tag label deteriorates significantly depending on the physical properties of an object to which the RF tag label is attached. The antenna disclosed in Patent Document 2 is designed on the premise that an RF tag label is attached to a conductor which is one of physical properties having communication impairment. There is also. Also, the specifications (eg, communication distance) required for RF tag labels tend to be very strict, and antennas mounted on RF tag labels must be individually designed for each item so as to satisfy the specifications required for RF tag labels. More and more cases are unavoidable.

  However, although the antenna of the RF tag label can be designed and manufactured individually, designing and manufacturing the antenna of the RF tag label individually increases the manufacturing cost of the RF tag label. When the object to which the RF tag label is to be attached is a lunch box sold at a convenience store or the like, the specifications required for the RF tag label include a microwave oven in addition to the communication performance required for the RF tag label. .

  Therefore, the present invention can reduce the manufacturing cost of the RF tag label even if the antenna to be mounted on the RF tag label is individually designed, and further, make the RF tag label with the individually designed antenna compatible with the microwave oven. With the goal. The fact that the RF tag label is compatible with the microwave means that the microwaves generated by the microwave can prevent discharge around the antenna, abnormal heating due to the discharge, and ignition due to the abnormal heating.

An RF tag label according to the present invention includes a matching circuit for impedance matching with an IC chip, and two coupling elements symmetrically arranged around the matching circuit and each electrically connected to the matching circuit. An inlay in which an antenna having a structure including the above is mounted on an inlay base material, an auxiliary antenna sheet in which two conductive patterns are formed on one surface of the auxiliary antenna base material using conductive ink, and the two conductive patterns are formed. And an adhesive layer laminated on the surface of the auxiliary antenna sheet.
In the RF tag label according to the present invention, the size of the inlay is smaller than the size of the auxiliary antenna sheet, and the inlay is attached to the auxiliary antenna sheet by using the adhesive layer. It is formed so as not to overlap with the matching circuit via the adhesive layer, but to overlap with any one of the coupling elements via the adhesive layer in a one-to-one correspondence. In the RF tag label according to the present invention, the adhesive layer is formed using an aqueous adhesive so that microwaves of a microwave oven passing through the adhesive layer are attenuated by 10% or more.

  The RF tag label according to the present invention is configured such that the conductive pattern can be used as an auxiliary antenna of the antenna in order to reduce the manufacturing cost of the RF tag label even if the antenna mounted on the RF tag label is individually designed. . Further, the RF tag label according to the present invention is configured so that microwaves of a microwave oven passing through the adhesive layer formed using an aqueous adhesive are attenuated by 10% or more in order to be compatible with a microwave oven. .

FIG. 2 is a diagram illustrating an RF tag label according to the embodiment. The figure explaining an auxiliary antenna sheet. FIG. 3 illustrates a structure of an antenna mounted on an RF tag. FIG. 4 illustrates a relationship between an antenna of a RF tag, a first conductive plate, and a second conductive plate.

  From here, preferred embodiments of the present invention will be described. Note that the following description does not limit the technical scope of the present invention, but is described to facilitate understanding of the present invention.

  The RF tag label 1 according to the present embodiment will be described in detail. FIG. 1 is a diagram illustrating an RF tag label 1 according to the present embodiment. FIG. 2 is a diagram illustrating the auxiliary antenna sheet 2. FIG. 3 is a diagram illustrating the structure of the antenna 41 mounted on the inlay 4.

  In FIG. 1, FIG. 1 (a) is a diagram showing the front surface of the RF tag label 1, FIG. 1 (b) is a diagram showing the back surface of the RF tag label 1, and FIG. 1 (c) is FIG. FIG. 2 is a diagram schematically showing an AA ′ cross section of FIG.

  As shown in FIG. 1C, the RF tag label 1 that communicates using a carrier wave in the UHF band is arranged symmetrically with respect to the matching circuit 410 to which the IC chip 42 is connected and the matching circuit 410 as a center. An inlay 4 in which an antenna 41 having a structure including two coupling elements 411 electrically connected to a matching circuit 410 is mounted on an inlay base material 40, and two conductive patterns 21 are formed on one side of an auxiliary antenna base material 20. And an adhesive layer 3 laminated on the surface of the auxiliary antenna sheet 2 on which the conductive patterns 21 are mounted.

  As shown in FIG. 1A, the conductive pattern 21 provided on the auxiliary antenna sheet 2 is not exposed on the surface of the RF tag label 1, and information necessary for product management or the like can be printed on this surface. .

  As shown in FIG. 1B and the like, on the back surface of the RF tag label 1, an inlay 4 having a size smaller than that of the auxiliary antenna sheet 2 is attached to the auxiliary antenna sheet 2 with the IC chip 42 protected by the adhesive layer 3. The part of the adhesive layer 3 which is stuck at the center and where the inlay 4 is not stuck is exposed on the back surface.

  The adhesive layer 3 exposed on the back surface of the RF tag label 1 is used not only for attaching the inlay 4 to the back surface of the auxiliary antenna sheet 2 but also for attaching the RF tag label 1 to a product. In the present embodiment, the microwave also serves to attenuate microwaves of the microwave oven that pass through the adhesive layer 3 and irradiate the inlay 4.

  In this embodiment, an aqueous adhesive is used for the adhesive layer 3 in consideration of attenuating microwaves generated by the microwave oven. For example, an emulsion-type acrylic water-based pressure-sensitive adhesive or a latex-type rubber-based water-based pressure-sensitive adhesive can be used for forming the pressure-sensitive adhesive layer 3. Since the water-based pressure-sensitive adhesive can maintain a semi-fixed state, by using the water-based pressure-sensitive adhesive for forming the pressure-sensitive adhesive layer 3, the electrons contained in the water-based pressure-sensitive adhesive are irradiated onto the inlay 4 through the pressure-sensitive adhesive layer 3. Can attenuate microwaves in the range.

  Even if an aqueous pressure-sensitive adhesive is used for the pressure-sensitive adhesive layer 3, microwaves generated by a microwave oven cannot be completely cut off (attenuation rate is almost 100%). In order to prevent the electric discharge, abnormal heating by this electric discharge, and ignition by this abnormal heating, the microwave of the microwave oven passing through the adhesive layer 3 should be attenuated by the adhesive layer 3 by 10% or more.

  Therefore, in the present embodiment, the adhesive layer 3 formed by using the aqueous adhesive is formed with a thickness at which the microwave of the microwave passing through the adhesive layer 3 attenuates by 10% or more. We are trying to respond. Although it depends on the type of the aqueous pressure-sensitive adhesive, the thickness of the pressure-sensitive adhesive layer 3 may be about 100 μm.

  The auxiliary antenna sheet 2 included in the RF tag label 1 will be described. In FIG. 2, FIG. 2A shows the surface of the auxiliary antenna sheet 2 on the front side of the RF tag label 1, and FIG. 2B shows the surface of the auxiliary antenna sheet 2 on the back side of the RF tag label 1. It is the figure which showed the surface.

  As shown in FIG. 2A, no conductive pattern is formed on the surface of the auxiliary antenna sheet 2 which is to be on the front side of the RF tag label 1, and as shown in FIG. On the surface on the back side, conductive patterns 21 formed of a thin film using a conductive material are symmetrically arranged one by one on the left and right with respect to the center line 2 a of the auxiliary antenna sheet 2.

  An insulating material is used for the sheet-like auxiliary antenna substrate 20. As the material of the auxiliary antenna substrate 20, it is preferable to use a plastic film such as polyethylene, polyethylene terephthalate, or polyimide. In the present embodiment, a conductive ink is used as a material for forming the conductive pattern 21, and the conductive pattern 21 is formed on the surface of the auxiliary antenna base 20 by printing.

  The antenna 41 mounted on the inlay 4 will be described. As shown in FIG. 3, the inlay 4 attached to the back surface of the RF tag label 1 has an IC chip 42 storing information and an antenna 41 connected to the IC chip 42 mounted on at least the inlay base material 40. With the configuration, the surface of the inlay 4 on which the IC chip 42 and the like are mounted becomes the surface in contact with the adhesive layer 3.

  The antenna 41 mounted on the inlay 4 includes a matching circuit 410, two coupling elements 411, and two waveguide lines 43. The matching circuit 410 of the antenna 41 mounted on the inlay 4 is an element for achieving impedance matching with the IC chip 42 mounted on the antenna 41, and has a loop shape.

  The coupling element 411 of the antenna 41 mounted on the inlay 4 is an element for electrically coupling with the conductive pattern 21 provided on the auxiliary antenna sheet 2. The two coupling elements 411 are arranged symmetrically with respect to the center line 4a of the inlay 4, the matching circuit 410 is arranged between the two coupling elements 411, and each coupling element 411 is connected via the waveguide 43. It is electrically connected to the matching circuit 410.

  For forming the antenna 41, a conductive material such as metal foil or conductive ink is used. When a metal foil is used as the conductive material, the antenna 41 can be formed by a foil stamping process or a foil transfer process. When conductive ink is used as the conductive material, the antenna 41 can be formed by printing. As the sheet-like inlay base material 40 on which the antenna 41 is mounted, a plastic film such as polyethylene, polyethylene terephthalate, or polyimide can be used as in the case of the auxiliary antenna base material 20.

  FIG. 4 is a diagram illustrating the relationship between the antenna 41 of the inlay 4 and the conductive pattern 21. In FIG. 4, FIG. 4 (a) is a diagram for explaining the positional relationship between the antenna 41 of the inlay 4 and the conductive pattern 21, and FIG. 4 (b) is an electrical diagram of the antenna 41 of the inlay 4 and the conductive pattern 21. FIG. 4 is a diagram for explaining a coupling relationship, and is a cross-sectional view taken along the line BB ′ in FIG. In FIG. 4, reference numerals a and b are given to the two elements for distinction. For example, when the two conductive patterns 21 are distinguished from each other, the conductive pattern 21 disposed on the left side is described as a conductive pattern 21a, and the conductive pattern 21 disposed on the right side is described as a conductive pattern 21b.

  In the present embodiment, in the RF tag label 1, the center line 2a of the auxiliary antenna sheet 2 and the center line 4a of the RF tag are aligned, and as shown in FIG. The interval L0 at which the patterns 21 are arranged is longer than the width W0 of the matching circuit 410 provided in the antenna 41 of the inlay 4, and the matching circuit 410 provided in the antenna 41 of the inlay 4 is provided between the two conductive patterns 21. Have been placed. By disposing the matching circuit 410 between the two conductive patterns 21, each of the conductive patterns 21 does not overlap with the matching circuit 410 via the adhesive layer 3, and the impedance matching by the matching circuit 410 is affected by the conductive pattern 21. Does not deviate significantly.

  Further, as shown in FIG. 4A, in the present embodiment, the interval L0 between the two conductive patterns 21 is shorter than the width W1 of the inlay 4 in the width direction of the antenna 41, and the two conductive patterns 21 are arranged. 21 overlaps with any one of the coupling elements 411 via the adhesive layer 3 in a one-to-one correspondence. In FIG. 4, the conductive pattern 21a disposed on the left overlaps the coupling element 411a disposed on the left via the adhesive layer 3, and the conductive pattern 21b disposed on the right is coupled with the coupling element disposed on the right. 411b overlaps with the adhesive layer 3 interposed therebetween. In FIG. 4, all of the coupling elements 411 overlap with the conductive pattern 21 via the adhesive layer 3, but a part of the coupling element 411 may overlap with the conductive pattern 21 via the adhesive layer 3. .

  As shown in FIG. 4B, since the conductive pattern 21 overlaps with the coupling element 411 provided in the antenna 41 of the inlay 4 with the adhesive layer 3 interposed therebetween, the conductive pattern 21 and the coupling element 411 are electrically connected by electrostatic coupling. To join. Considering that the conductive pattern 21 and the coupling element 411 are electrically coupled by electrostatic coupling, it is preferable that the surface resistivity of the conductive pattern 21 be 0.1 Ω / sq or more and 1 KΩ / sq or less. Is preferably 0.001 Ω / sq or more and 1 Ω / sq or less.

  By electrically coupling the conductive pattern 21 and the coupling element 411 by electrostatic coupling, the conductive pattern 21 can be used as a radiating element of the antenna 41 mounted on the inlay 4, and by changing the pattern shape of the conductive pattern 21, The characteristics of the antenna 41 mounted on the RF tag label 1 can be changed. Since the pattern shape of the matching circuit 410 of the antenna 41 depends on the IC chip 42 mounted on the RF tag label 1, if the IC chip 42 is the same regardless of the item, the antenna 41 mounted on the inlay 4 can be made common and the size can be reduced. In the RF tag label 1, the antenna design that needs to be individually performed for each item is only the design of the conductive pattern 21.

  As described above, in the RF tag label 1 of the present embodiment, since the conductive pattern 21 can be formed on the auxiliary antenna base material 20 by using a conductive ink as a material of the conductive pattern 21 and printing, the aluminum foil is etched. The shape of the conductive pattern 21 can be changed more easily than when the conductive pattern 21 is formed, and the material cost of the conductive pattern 21 having a larger area can be reduced. In addition, since the inlay 4 can be reduced in size and shared for each item, the cost can be reduced by mass production even if aluminum foil is used for the antenna 41, for example. Furthermore, in the RF tag label 1 according to the present embodiment, the pressure-sensitive adhesive layer 3 formed by using the water-based pressure-sensitive adhesive is formed to have a thickness at which the microwave generated by the microwave is attenuated by 10% or more. We are trying to respond.

DESCRIPTION OF SYMBOLS 1 RF tag label 2 Auxiliary antenna sheet 20 Auxiliary antenna base material 21 Conductive pattern 3 Adhesive layer 4 Inlay 40 Inlay base material 41 Antenna 410 Matching circuit 411 Coupling element 42 IC chip

Claims (1)

An inlay-based antenna includes a matching circuit for impedance matching with an IC chip, and an antenna having a structure including two coupling elements symmetrically arranged around the matching circuit and electrically connected to the matching circuit. An auxiliary antenna sheet in which two conductive patterns are formed on one surface of the auxiliary antenna base material using conductive ink and an adhesive layer laminated on the surface of the auxiliary antenna sheet;
The inlay has a size smaller than the size of the auxiliary antenna sheet and is attached to the auxiliary antenna sheet using the adhesive layer, and the two conductive patterns are each aligned with the alignment layer via the adhesive layer. Is formed so as not to overlap with a circuit, and to overlap one of the coupling elements in a one-to-one correspondence via the adhesive layer;
The adhesive layer is formed using an aqueous adhesive so that microwaves of a microwave oven passing through the adhesive layer are attenuated by 10% or more.
An RF tag label, characterized in that: