JP2014072643A - Rf-id medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shift a resonance frequency and extend a communication distance without making an impact on an IC chip.SOLUTION: The RF-ID medium includes: an inlet base material 16; antennas 12a, 12b formed extending in a direction mutually away from feeding points 15a, 15b on the inlet base material 16; and an IC chip 11 mounted on the inlet base material 16 so as to be connected to the feeding points 15a, 15b. Metal layers 20a, 20b are placed in a region facing the opposite ends from the feeding points 15a, 15b of the antennas 12a, 12b such that they straddle the ends.

Description

  The present invention relates to an RF-ID medium in which information is written to and read from an IC chip at a predetermined resonance frequency, and more particularly to a method for adjusting a resonance frequency.

  In recent years, with the progress of the information society, information is recorded on a card, and information management and settlement using the card are performed. Information is recorded on a label or tag attached to a product or the like, and the product or the like is managed using the label or tag. In information management using such a card, label, or tag, a non-contact IC card or non-contact that can write and read information in a non-contact state on the card, label, or tag. Type IC labels or non-contact type IC tags are rapidly spreading due to their excellent convenience.

  RF-ID media such as a non-contact type IC card, a non-contact type IC label, or a non-contact type IC tag is formed such that a conductive antenna is formed on a base substrate and is connected to the antenna. An inlet on which an IC chip is mounted is configured to be sandwiched between a surface sheet and a card substrate, and information is written to and read from the IC chip at a predetermined resonance frequency.

  However, in an RF-ID medium in which information is written or read at a frequency in the UHF band or microwave band, the resonance frequency of the antenna is likely to change due to the influence of surrounding substances. As a result, the communication performance of the antenna may deteriorate and the communication distance may be shortened.

The resonance frequency f of the antenna is
f = 1 / {2π (LC) ^1/2 }
Therefore, the antenna L can be designed according to the usage environment by adjusting these parameters. However, if the antenna is designed every time according to the usage environment, it takes an enormous amount of time, and the design according to the usage environment may not be possible due to design restrictions such as the antenna size.

  Therefore, in an IC tag label in which an antenna including a loop portion is formed on a base material, there is a technology for increasing the capacitance C by arranging a metal layer so as to overlap the loop portion and shifting the resonance frequency to the low frequency side. Patent Document 1 discloses this.

  Further, in a non-contact IC tag in which an antenna for a UHF band or a microwave band is formed on a base material, metal is formed in all regions except for a portion facing the IC chip on the side opposite to the base antenna. Patent Document 2 discloses a technique in which a layer is provided so that it is less likely to be affected by moisture when applied to a liquid container.

JP 2012-123671 A JP 2007-31955 A

  However, in the case where the metal layer is arranged so as to overlap the antenna as described above, if the antenna is small, the metal layer may be arranged in the vicinity of the IC chip. There is a possibility that the chip cannot be written or read due to the influence of the metal layer.

  The present invention has been made in view of the problems of the conventional techniques as described above, and can shift the resonance frequency and extend the communication distance without affecting the IC chip. The purpose is to provide media.

In order to achieve the above object, the present invention provides:
A base substrate, an antenna formed on the base substrate so as to extend in a predetermined direction from a feeding point, and an IC chip mounted on the base substrate so as to be connected to the feeding point In the RF-ID media
At least one conductive layer is disposed in a region facing the end of the antenna opposite to the feeding point so as to straddle the end.

  In the present invention configured as described above, the conductive layer arranged so as to straddle the end of the region facing the end of the antenna increases the area that functions as the antenna, extends the communication distance, and resonates. The frequency is shifted, and the conductive layer is arranged in a region facing the end opposite to the feeding point to which the IC chip is connected, and thus the IC chip is not affected.

  In addition, the antenna has a folded portion that is folded at the end opposite to the feeding point, and the width of the conductive layer in the direction orthogonal to the predetermined direction in which the antenna extends is opposite to the feeding point of the antenna. By adopting a configuration that is wider than the width in the same direction including the folded portion at the end portion, the communication distance is greatly extended and the shift amount of the resonance frequency is increased.

  According to the present invention, an antenna formed on a base substrate so as to extend in a predetermined direction from a feeding point extends over a region facing the end opposite to the feeding point to which the IC chip is connected. Since the conductive layer is disposed on the substrate, the resonance frequency can be shifted and the communication distance can be extended without affecting the IC chip.

  In addition, the antenna has a folded portion that is folded at the end opposite to the feeding point, and the width of the conductive layer in the direction orthogonal to the predetermined direction in which the antenna extends is opposite to the feeding point of the antenna. In the case where the width is larger than the width in the same direction including the folded portion at the end portion, the communication distance can be greatly increased and the shift amount of the resonance frequency can be increased.

It is a figure which shows 1st Embodiment of RF-ID media of this invention, (a) is a figure which shows an internal structure, (b) is sectional drawing of the AA 'part shown to (a). . It is a graph which shows the change of the frequency characteristic by having a metal layer in the IC tag shown in FIG. It is a figure which shows the structure which has arrange | positioned the metal layer so that it might overlap in the edge part of an antenna, without straddling the edge part of an antenna in the IC tag shown in FIG. It is a graph which shows the change of the frequency characteristic by having a metal layer in the IC tag shown in FIG. It is a figure which shows 2nd Embodiment of RF-ID media of this invention. It is a graph which shows the change of the frequency characteristic by having a metal layer in the IC tag shown in FIG. It is a figure which shows 3rd Embodiment of RF-ID media of this invention. It is a graph which shows the change of the frequency characteristic by having a metal layer in the IC tag shown in FIG. FIG. 6 is a diagram for explaining a difference in communication distance and frequency shift amount depending on the ratio of the area of the metal layer facing the antenna in the IC tag shown in FIG. 5, and (a) is a diagram showing the configuration of the IC tag. (B) is a graph which shows the frequency characteristic in the IC tag shown to (a).

  Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a diagram showing a first embodiment of an RF-ID medium according to the present invention. FIG. It is sectional drawing.

  As shown in FIG. 1, the present embodiment is an IC tag 1 in which an inlet 10 is sandwiched between two surface base materials 30a and 30b.

  The inlet 10 is configured such that two antennas 12a and 12b are formed on an inlet base material 16 serving as a base base material, and an IC chip 11 is mounted.

  The two antennas 12a and 12 have feeding points 15a and 15b to which the IC chip 11 is connected, respectively, in regions facing each other via a gap, and extend while spreading radially in a direction away from the feeding points 15a and 15b. It has a bowtie shape. The folded portions 13a and 13b are formed by folding back at the ends of the antennas 12a and 12b opposite to the feeding points 15a and 15b. Further, the two antennas 12 a and 12 b have a short-circuit portion 14 that is short-circuited in parallel with the IC chip 11.

  The inlet 10 configured as described above is sandwiched between the two surface base materials 30a and 30b from the front and back and is bonded to the surface base materials 30a and 30b by the adhesive 50, but the antennas 12a and 12b of the inlet 10 are provided. The metal layers 20a and 20b serving as conductive layers are sandwiched between the surface on which the surface is formed and the surface base material 30b.

The metal layers 20a and 20b are made of, for example, an aluminum foil having a thickness of about 10 μm to 500 μm, and the end portions of the antenna layers 12a and 12b are opposed to the end portions on the side opposite to the feeding points 15a and 15b. It is arranged to straddle. Further, the width L ₂ in the direction orthogonal to the direction in which the antennas 12 a and 12 b of the metal layers 20 a and 20 b are arranged is narrower than the width L ₁ in the same direction at the ends of the antennas 12 a and 12 b. The metal layers 20a and 20b having such a configuration are bonded to the inlet 10 by an insulating adhesive layer 40 formed on the surface of the inlet 10 where the antennas 12a and 12b are formed.

  The IC tag 1 configured as described above is in close proximity to an information writing / reading device (not shown) provided outside, thereby resonating with radio waves from the information writing / reading device and receiving antennas 12a and 12b. Current is supplied to the IC chip 11, whereby information is written from the information writing / reading device to the IC chip 11 in a non-contact state, or the information written on the IC chip 11 is transmitted to the antenna. It is read by the information writing / reading device via 12a, 12b.

  Below, the effect | action by having the metal layers 20a and 20b in the IC tag 1 mentioned above is demonstrated.

  FIG. 2 is a graph showing changes in frequency characteristics due to the presence of the metal layers 20a and 20b in the IC tag 1 shown in FIG. 1, and solid lines in the figure indicate frequency characteristics when the metal layers 20a and 20b are arranged. The broken line in the figure indicates the frequency characteristics when the metal layers 20a and 20b are not arranged.

  As shown in FIG. 2, in the IC tag 1 shown in FIG. 1, the communication distance is greater when the metal layers 20a and 20b are disposed than when the metal layers 20a and 20b are not disposed. Is getting longer. In addition, the peak value frequency when the metal layers 20a and 20b are arranged is shifted to a lower frequency side than the peak value frequency when the metal layers 20a and 20b are not arranged.

  Here, the frequency characteristic when the metal layer is arranged so as to overlap the end portion of the antenna without straddling the end portion of the antenna will be described.

  FIG. 3 is a diagram showing a configuration in which the metal layer in the IC tag shown in FIG. 1 is arranged so as to overlap the end portion of the antenna without straddling the end portion of the antenna. FIG. 4 is a graph showing changes in frequency characteristics due to the presence of the metal layers 120a and 120b in the IC tag 101 shown in FIG. 3, and solid lines in the figure indicate frequency characteristics when the metal layers 120a and 120b are arranged. The broken line in the figure shows the frequency characteristics when the metal layers 120a and 120b are not arranged.

  As shown in FIG. 3, the present configuration is different from that shown in FIG. 1 in that the metal layers 120a and 120b are opposed to the ends of the antennas 12a and 12b opposite to the feeding points 15a and 15b. The difference is that the antennas 12a and 12b are arranged so as not to straddle the ends.

  In the IC tag 101 configured as described above, as shown in FIG. 4, the frequency characteristics change almost between the case where the metal layers 120 a and 120 b are arranged and the case where the metal layers 120 a and 120 b are not arranged. do not do.

  Thus, as shown in FIG. 3, the metal layers 120a and 120b do not straddle this end in the region facing the end opposite to the feeding points 15a and 15b of the antennas 12a and 12b. When the antennas 12a and 12b are arranged so as to overlap with each other, the frequency characteristics do not change as compared with the case where the metal layers 120a and 120b are not arranged, whereas the metal layers as shown in FIG. When 20a and 20b are arranged so as to straddle the ends of the antennas 12a and 12b opposite to the feeding points 15a and 15b, the metal layers 20a and 20b are arranged. As compared with the case where the communication is not performed, the communication distance becomes longer and the frequency of the peak value shifts. This is because the area that functions as an antenna is increased by the metal layers 20a and 20b arranged so as to straddle the end portions of the antennas 12a and 12b facing the end portions opposite to the feeding points 15a and 15b. It is by doing. Therefore, the communication distance and the amount of frequency shift change according to the area of the region where the antennas 12a, 12b and the metal layers 20a, 20b do not face each other. Further, the metal layers 20a and 20b for increasing the area functioning as an antenna are opposed to the ends of the antennas 12a and 12b opposite to the feeding points 15a and 15b to which the IC chip 11 is connected. Since the IC chip 11 is less affected by the metal layers 20a and 20b, the communication distance is increased.

  In this embodiment, the metal layers 20a and 20b are provided on the surface side where the antennas 12a and 12b of the inlet 10 are formed as described above, but the surfaces where the antennas 12a and 12b of the inlet 10 are formed. The metal layers 20a and 20b may be provided on the opposite side. Further, the RF-ID media of the present invention is not limited to the IC tag 1 as described above, but can be configured as an IC label by sticking a release paper in a peelable manner instead of the surface base material 30b.

(Second Embodiment)
FIG. 5 is a diagram showing a second embodiment of the RF-ID media of the present invention and showing the internal configuration. FIG. 6 is a graph showing changes in frequency characteristics due to the presence of the metal layers 220a and 220b in the IC tag 201 shown in FIG. 5, and solid lines in the figure indicate frequency characteristics when the metal layers 220a and 220b are arranged. The broken line in the figure shows the frequency characteristics when the metal layers 220a and 220b are not arranged.

In this embodiment, as shown in FIG. 5, the width L ₂ in the direction perpendicular to the direction in which the antennas 12a and 12b of the metal layers 220a and 220b are arranged is the end of the antennas 12a and 12b. The difference is that the width L ₁ is equal to the width L ₁ in the same direction.

  Also in the IC tag 201 configured in this way, as shown in FIG. 6, communication is performed when the metal layers 220 a and 220 b are disposed, compared to when the metal layers 220 a and 220 b are not disposed. The distance is long. Moreover, the frequency of the peak value when the metal layers 220a and 220b are arranged is shifted to a lower frequency side than the frequency of the peak value when the metal layers 220a and 220b are not arranged.

(Third embodiment)
FIG. 7 is a diagram showing a third embodiment of the RF-ID media of the present invention and showing the internal configuration. FIG. 8 is a graph showing changes in frequency characteristics due to the presence of the metal layers 320a and 320b in the IC tag 301 shown in FIG. 7, and solid lines in the figure indicate frequency characteristics when the metal layers 320a and 320b are arranged. The broken line in the figure indicates the frequency characteristics when the metal layers 320a and 320b are not disposed.

As shown in FIG. 7, this embodiment has a width L ₂ in the direction orthogonal to the direction in which the antennas 12a and 12b of the metal layers 320a and 320b are arranged, as shown in FIG. The difference is that it is wider than the width L ₁ in the same direction in the portion. Thus, IC tag 301 of this embodiment, the metal layer 320a, the width L ₂ of 320b, the antenna 12a, a feeding point 15a of 12b, 15b in the same direction, including the folded portions 13a, 13b at the end opposite It is wider than the width L ₁ .

Also in the IC tag 301 configured in this way, as shown in FIG. 8, communication is performed when the metal layers 320 a and 320 b are disposed, compared to when the metal layers 320 a and 320 b are not disposed. The distance is long. Moreover, the frequency of the peak value when the metal layers 320a and 320b are arranged is shifted to the lower frequency side than the frequency of the peak value when the metal layers 320a and 320b are not arranged. Note that the width L ₂ in the direction perpendicular to the direction in which the antennas 12 a, 12 b of the metal layers 320 a, 320 b are arranged is wider than the width L ₁ in the same direction at the ends of the antennas 12 a, 12 b. The distance and the shift amount of the peak value are larger than those shown in FIG.

Thus, if the metal layer is disposed so as to straddle the end of the antenna 12a, 12b opposite to the feeding point 15a, 15b, the metal layer antenna 12a, The communication distance can be increased regardless of the width L ₂ in the direction orthogonal to the direction in which the lines 12 b are aligned with respect to the width L ₁ in the same direction at the ends of the antennas 12 a and 12 b. The frequency characteristics can be shifted. As can be seen by comparing the frequency characteristics shown in FIGS. 2, 6 and 8, the width L ₂ of the metal layers 320a and 320b as shown in FIG. 7 is equal to the feed points 15a and 12b of the antennas 12a and 12b. By adopting a configuration that is wider than the width L _{1 in the} same direction including the folded portions 13a and 13b at the end opposite to 15b, the communication distance can be significantly increased, and the peak value shift amount is also increased. Can be bigger.

  Note that the RF-ID medium of the present invention shifts the frequency characteristics to the low frequency side as shown in the above-described embodiment. Therefore, if the frequency characteristic in the state where the metal layer is not provided is shifted to a higher frequency side than the predetermined one, the frequency characteristic is adjusted by adjusting the area of the region where the metal layer does not face the antenna. It can be set to a predetermined one.

  Here, how the communication distance and the frequency shift amount change depending on the area ratio of the region where the metal layer faces the antenna will be described.

  FIG. 9 is a diagram for explaining the difference in the communication distance and frequency shift amount depending on the area ratio of the area where the metal layers 220a and 220b face the antennas 12a and 12b in the IC tag 201 shown in FIG. (A) is a figure which shows the structure of IC tag 201, (b) is a graph which shows the frequency characteristic in IC tag 201 shown to (a). In addition, the broken line in FIG.9 (b) shows the frequency characteristic when the metal layers 320a and 320b are not arrange | positioned.

  As shown in FIG. 9A, in this example, the metal layers 220a and 220b are moved in the direction in which the antennas 12a and 12b extend, thereby feeding the outer ends of the metal layers 220a and 220b and the antennas 12a and 12b. The distance b between the antenna end 17 on the side opposite to the points 15a and 15n is changed, thereby changing the ratio of the area of the metal layers 320a and 320b not facing the antennas 12a and 12b to change the frequency characteristics. It was measured.

  As a result, when the distance b is 90% of the width a of the metal layers 320a and 320b, that is, when the ratio of the area of the metal layers 320a and 320b not facing the antennas 12a and 12b is 90% of the whole. As shown by the solid line in FIG. 9B, the communication distance extends by about 2.5 m and the resonance frequency as compared with the case where the metal layers 320a and 320b shown by the broken line in FIG. 9B are not arranged. Is shifted to the low frequency side by about 30 MHz.

  When the distance b is 50% of the width a of the metal layers 320a and 320b, that is, when the ratio of the area of the metal layers 320a and 320b not facing the antennas 12a and 12b is 50% of the total, As shown by the two-dot chain line in FIG. 9B, the communication distance is extended by about 1.5 m as compared with the case where the metal layers 320a and 320b are not arranged, and the resonance frequency is shifted to the lower frequency side by about 10 MHz. ing.

  When the distance b is 25% of the width a of the metal layers 320a and 320b, that is, when the ratio of the area of the metal layers 320a and 320b not facing the antennas 12a and 12b is 25% of the total, As shown by the one-dot solid line in FIG. 9B, the communication distance is extended by about 1 m and the resonance frequency is shifted to the lower frequency side by about 10 MHz as compared with the case where the metal layers 320a and 320b are not arranged.

  Thus, as the proportion of the area of the metal layer 320a, 320b that does not face the antennas 12a, 12b increases, the communication distance increases and the shift amount of the peak value of the resonance frequency also increases. For this reason, in order to obtain the above-described effects remarkably, it is preferable that the ratio of the area of the metal layers 220a and 220b not facing the antennas 12a and 12b is 50% or more of the entire area.

  In the above-described embodiment, the metal layers 20a, 20b, 220a, 220b, 320a, 320b are provided in the regions facing the ends of the antennas 12a, 12b opposite to the feeding points 15a, 15b, respectively. However, the above-described effects can be obtained by providing a metal layer in a region facing the end opposite to the feeding point 15a, 15b of either one of the antennas 12a, 12b.

  Further, in the above-described embodiment, the example in which the two antennas 12a and 12b are connected to the IC chip 11 has been described as an example. However, even if one antenna is connected to the IC chip 11 Good. Further, the shape is not limited to the bow tie shape as described above, and may be a meander shape or the like.

DESCRIPTION OF SYMBOLS 1,101,201,301 IC tag 10 Inlet part 11 IC chip 12a, 12b Antenna 13a, 13b Folding part 14 Short-circuit part 15a, 15b Feeding point 16 Inlet base material 17 Antenna end part 20a, 20b, 120a, 120b, 220a, 220b, 320a, 320b Metal layer 30a, 30b Surface base material 40, 50 Adhesive layer

Claims (2)

A base substrate, an antenna formed on the base substrate so as to extend in a predetermined direction from a feeding point, and an IC chip mounted on the base substrate so as to be connected to the feeding point In the RF-ID media
An RF-ID medium, wherein at least one conductive layer is disposed in a region facing the end of the antenna opposite to the feeding point so as to straddle the end. The RF-ID medium according to claim 1,
The antenna has a folded portion folded at an end opposite to the feeding point,
The RF-ID medium, wherein the conductive layer has a width in a direction orthogonal to the predetermined direction that is wider than a width in the same direction including the folded portion at an end of the antenna on the side opposite to the feeding point.

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