JP3647446B1 - Magnetic shield sheet for tag and tag - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic shield sheet for a tag capable of shielding a magnetic field without losing energy of the magnetic field, and a tag using the same.
A magnetic shield sheet (10) is formed by laminating a shield layer (11) and an adhesive layer (12). Since the shield layer 11 is made of a material having a large real part μ ′ of the complex relative permeability μ, when the shield layer 11 is provided in a magnetic field, the lines of magnetic force concentrate through the shield layer. Therefore, by using the magnetic shield sheet 10, it is possible to shield the magnetic field and prevent the magnetic field of one region partitioned by the magnetic shield sheet 10 from leaking to the other region. Furthermore, since the shield layer 10 is made of a material having a small imaginary part μ ″ of the complex relative permeability μ, even if the shield layer 11 is provided in the magnetic field, the loss of magnetic field energy due to the provision of the shield layer 11 is reduced. Can be suppressed.
[Selection] Figure 1

Description

The present invention relates to a tag using this magnetic shield sheet and tag for shielding magnetic field.

  As RFID (Radio Frequency Identification), there are an RFID tag and a non-contact IC card. In addition to this, the practical use of a mobile terminal having an RFID function is being studied. There are the following two types of communication means for RFID tags. One is an electromagnetic induction method in which power is supplied by communication between a coil and a coil to communicate, and a frequency of 135 kHz or 13.56 MHz is used. The other one is a radio wave system, and frequencies of 433 MHz, 900 MHz, 2.8 GHz, and 5.8 GHz are used. The frequency mainly used for the non-contact IC card is 4.91 MHz for the contact type and 13.56 MHz for the proximity type. By using the 13.56 MHz band, wireless communication within a range of several centimeters to 1 m is possible, and practical use has been attempted mainly using this band.

  FIG. 11 is a cross-sectional view schematically showing a tag 1 which is a conventional technique. The tag 1 includes an antenna 2 that transmits and receives an electromagnetic wave signal, and an integrated circuit (IC) 3 that processes a signal transmitted and received by the antenna 2. When the tag 1 receives the request signal from the reading device, the tag 1 transmits the information stored in the IC 3, in other words, the information held in the tag 1 can be read by the reading device. Configured. This tag 1 is provided by being attached to a product, for example, and is used for product management such as prevention of product theft and grasping of inventory status.

  When the tag 1 is used by being attached to a metal product, and the metal member 4 is present in the vicinity of the antenna 2, the magnetic field lines of the magnetic field formed by the electromagnetic wave signal transmitted and received by the antenna 2 are made of the metal member. 4, and an eddy current is generated in the metal member 4. When eddy currents are generated in this way, the energy of electromagnetic waves is converted into heat energy and absorbed. If energy is absorbed in this way, the electromagnetic wave signal is greatly attenuated and cannot be transmitted or received. Therefore, such a tag 1 cannot be used in the vicinity of the metal member 4.

  FIG. 12 is a cross-sectional view schematically showing a tag 1A which is another conventional technique. The tag 1A shown in FIG. 12 is similar to the tag 1 of FIG. 11, and the same reference numerals are given to corresponding portions, and only different configurations will be described. In order to solve the problem of the tag 1 of FIG. 11, the tag 1 </ b> A of FIG. 12 includes a magnetic absorption plate 7 provided so as to be disposed between the member 4 that is an article to be attached and the antenna 2. Configured as follows. The magnetic absorption plate 7 is made of a material having a high magnetic permeability such as sendust, ferrite and carbonyl iron, and thus a material having a high complex relative permeability.

  The complex relative permeability has a real part and an imaginary part, and the complex relative permeability increases as the real part increases. In other words, a material having a high complex relative permeability has a high real part in the complex relative permeability. When a material having a high real part in the complex relative permeability exists in the magnetic field, the magnetic field lines are concentrated in the member. Therefore, by providing the magnetic absorption plate 7, the magnetic field is prevented from leaking, and information can be read even if the metal member 4 is present in the vicinity. Such a tag 1A is disclosed in, for example, Patent Document 1.

JP 2000-113142 A

  In the tag 1A shown in FIG. 12, the magnetic absorption plate 7 made of a material having a high complex relative permeability is provided to prevent the magnetic field from leaking. Sendust, ferrite, carbonyl iron and the like are used as materials having a high complex relative permeability. When these materials are filled in a binder such as a polymer, the real part in the complex relative permeability of the sheet as an insulating sheet can be increased, the magnetic field can be shielded, and magnetic field leakage can be prevented. The imaginary part of the complex relative permeability is also high. This is because the real part of the complex relative permeability at a specific frequency is designed to be high, but at the same time, the imaginary part of the complex relative permeability is not designed to be low. A material having a high imaginary part of complex relative permeability loses energy of the magnetic field, specifically, converts the magnetic field energy into thermal energy and absorbs it. If a magnetic absorption plate made of a material having a high complex relative permeability is used as described above, loss of electromagnetic wave energy in the magnetic absorption plate is caused even if loss in the metal member 4 can be prevented. There's a problem. In actual use, not only the use of a magnetic shield material but also the influence of the metal surface is avoided by widening the distance between the antennas from the metal surface as much as possible (1-2 mm). In other words, when these materials are used, even if they are used as a magnetic shield material for RFID tags (also called a magnetic yoke), a considerable thickness is required including the space.

Therefore, an object of the present invention, without loss of energy of the magnetic field, it is possible to shield the magnetic field is to provide a further tag using the magnetic shield sheet and this tag is made thin than before. A mobile terminal (for example, a mobile phone) having an RFID function is shielded on the inner surface of the casing. Further, since the space for the antenna is very narrow due to the reduction in thickness and the environment is easily affected by the metal surface, a magnetic shield sheet for a high-performance tag corresponding to this is provided. Furthermore, by using this sheet, an unprecedented thin RFID tag antenna can be installed in a mobile terminal, and these thin systems ( tags ) including a magnetic shield sheet for tags are provided.

Furthermore, in the present invention, by having a magnetic shielding property with respect to the above-mentioned specific frequency, it contributes to be useful as a metal-compatible RFID tag, and at other frequencies (for example, 100 MHz to 6 GHz), the real part of the complex relative permeability and even as high as the imaginary part, for example, to provide a tag using the same magnetic shield sheet and tag, characterized in that also serves as an inhibitory effect of such unwanted radiation noise. That is, the present invention provides an intelligent sheet that suitably converts and functions the magnetic permeability and dielectric constant at two or more frequencies.

The present invention has an antenna element for transmitting and receiving an electromagnetic wave signal having a frequency of 13.56 MHz, and is electrically connected to the antenna element and transmits a signal from the antenna element in response to a signal received by the antenna element. When using a tag including an integrated circuit in the vicinity of a metal member, a tag magnetic shield sheet provided between the antenna element and the metal member,
Frequency Ri imaginary part mu "is 6 der following real part mu 'is not less than 30 and the complex relative permeability mu of the complex relative permeability mu at 13.56MHz electromagnetic waves,
The imaginary part ε ″ of the complex relative dielectric constant ε in an electromagnetic wave having a frequency of 13.56 MHz is 500 or less,
For a tag comprising a shield layer having a real part μ ′ of a complex relative permeability μ of 7 or more and an imaginary part μ ″ of a complex relative permeability μ of 7 or more in an electromagnetic wave having a frequency of 100 MHz to 1 GHz It is a magnetic shield sheet.

According to the present invention, the magnetic shield sheet for tags is provided with a shield layer. In the shield layer, the larger the real part μ ′ of the complex relative permeability μ is, the more the magnetic lines of force (magnetic flux) pass. The smaller the real part μ ′ of the complex relative permeability μ is, the more the magnetic line of force (magnetic flux) is. It becomes composition that is hard to pass. The shield layer is configured such that the larger the imaginary part μ ″ of the complex relative permeability μ, the more the magnetic field energy is lost, and the smaller the imaginary part μ ″ of the complex relative permeability μ, the less likely the magnetic field energy is lost.

With respect to the electromagnetic wave of 13.56 MHz, the shield layer has a real part μ ′ of the complex relative permeability μ as large as 30 or more and an imaginary part μ ″ of the complex relative permeability μ as small as 6 or less. to the magnetic field formed by electromagnetic waves 56 MHz, the magnetic force lines (magnetic flux) is liable as to concentrate the shield layer, it is possible to make on not lost the energy of the magnetic field at that. Therefore the magnetic shielding tag By using the sheet, 13.56 MHz electromagnetic waves can be shielded from leaking while suppressing energy loss to a small level.
Further, for electromagnetic waves of 13.56 MHz, the imaginary part ε ″ of the complex dielectric constant ε is as small as 500 or less. The imaginary part ε ″ of the complex dielectric constant ε is a measure of the conductivity of the shield layer. When the imaginary part ε ″ of the complex relative dielectric constant ε is large, the conductivity is developed. When the conductivity is developed, an eddy current is generated when the magnetic flux passes through the shield layer. When the eddy current is generated as described above, for example, when used for improving the wireless communication environment, the magnetic flux is attenuated to hinder wireless communication. On the other hand, the imaginary part ε ″ of the complex relative dielectric constant ε is By reducing the size, it is possible to prevent the occurrence of the above problem and prevent a wireless communication failure, thereby realizing a suitable wireless communication environment.

Furthermore, the shield layer has an actual part μ ′ of the complex relative permeability μ of 7 or more and is never too small for an electromagnetic wave of 100 MHz to 1 GHz, and an imaginary part μ ″ of the complex relative permeability μ is 7 or more. large. This respect to the magnetic field formed by electromagnetic waves of 100 MHz to 1 GHz, the magnetic field lines (magnetic flux) is arranged to pass shield layer, it is possible to lose energy of the magnetic field. Therefore the use of the magnetic shield sheet tag Can absorb electromagnetic waves of 100 MHz to 1 GHz.

The magnetic shield sheet for such tags, in the case of using the tag for wireless communication using electromagnetic waves of 1 3.56MHz in the vicinity of the metallic member, disposed between the antenna element and a metal member Used. This prevents the 13.56 MHz electromagnetic wave from leaking to the metal member side, and prevents the 13.56 MHz electromagnetic wave energy from being absorbed by the metal object. Moreover, the magnetic loss sheet for the tag itself has a small magnetic loss. Therefore , even if the tag is used in the vicinity of a metal member , radio communication can be suitably performed using 13.56 MHz electromagnetic waves. The electromagnetic wave of 13.56 MHz is mainly used for communication of an RFID (Radio Frequency IDentification) tag, for example. Therefore, communication can be suitably performed using the RFID tag.

Moreover , since the magnetic shield sheet for tags can absorb electromagnetic waves of 100 MHz to 1 GHz, unnecessary radiation noise and the like can be suppressed with respect to electromagnetic waves of 100 MHz to 1 GHz. Therefore, the loss can be suppressed small with respect to the 13.56 MHz electromagnetic wave used for communication by the tag, and the unnecessary 100 MHz to 1 GHz electromagnetic wave can be absorbed, and communication can be performed more suitably.

In the present invention, the shield layer is made of a material in which a flat soft magnetic metal powder is mixed with a polymer,
The soft magnetic metal powder is characterized in that it is densely dispersed in an oriented state without causing shape deformation including distortion and bending .

According to the present invention, the flat soft magnetic metal powder is densely dispersed in the polymer in an oriented state without causing shape deformation including distortion and bending, thereby forming a shield layer. With such a configuration, with respect to an electromagnetic wave of 13.56 MHz, the real part μ ′ of the complex relative permeability μ is as large as 30 or more and the imaginary part μ ″ of the complex relative permeability μ is as small as 6 or less. However, for electromagnetic waves of 100 MHz to 1 GHz, the real part μ ′ of the complex relative permeability μ is never too small as 7 and the imaginary part μ ″ of the complex relative permeability μ is as large as 7 or more. The shield layer can be formed. Therefore , a magnetic shield sheet for tags that achieves the above-described excellent effects can be realized.

The present invention, the volume resistivity is equal to or is more than 10 ⁶ Ω cm.
According to the present invention, by ensuring that the volume resistivity value is 10 ⁶ Ωcm or more and ensuring insulation, generation of eddy currents is suppressed, and electromagnetic wave shielding properties that reflect radiation noise are not imparted.

The present invention is characterized by having flexibility.
According to the present invention, the magnetic shield sheet for tags has flexibility and can be freely deformed. Thereby, there are few restrictions on an installation place and it can be used for a wide use. For example, when it is used by being attached to an article, it can be provided following the shape of the article.

Further, the present invention is characterized in that thermal conductivity is imparted.
According to the present invention, an IC substrate or a power supply unit serving as a heat source may be close to each other, and excellent thermal conductivity leads to suppression of temperature rise and prevention of performance degradation due to exposure to high temperature.

Further, the present invention is characterized in that flame retardancy is imparted.
According to the present invention, the magnetic shield sheet for tags can obtain flame retardancy. Electronic devices such as mobile phones may also be required to have flame retardancy for the polymer material that is used in the interior. The magnetic shield sheet for tags can be suitably used as a material constituting such an article or attached to the article.

Further the invention features that the adhesive is applied to at least one surface portion.

According to the present invention, the tag magnetic shield sheet is provided with adhesiveness on at least one surface portion. Therefore, when attached to an article, the tag magnetic shield sheet is attached to the article using the adhesiveness. Can do. Thus, the tag magnetic shield sheet can be easily attached to the article. Therefore, the work for using the tag magnetic shield sheet can be facilitated.

The present invention includes an antenna element for frequency to transmit and receive electromagnetic signals 13.56 MHz,
An integrated circuit electrically connected to the antenna element and transmitting a signal from the antenna element in response to a signal received by the antenna element;
It is a tag characterized by including the magnetic shield sheet for tags as described in any one of Claims 1-7 .

According to the present invention, the magnetic shield sheet tag is provided between the antenna element and the metal member. Thus, tags can also be provided in the vicinity of the metallic member, without the energy of electromagnetic wave is absorbed by a metal member, it can be suitably received by the antenna elements. Thus, even if it is provided in the vicinity of a metal member, a tag that can be suitably transmitted and received by the antenna element can be realized.

According to the present invention, an electromagnetic wave of 13.56 MHz can be shielded without being attenuated. Therefore, when wireless communication is performed using an electromagnetic wave of 13.56 MHz, even if a metal member exists in the vicinity of the antenna element , wireless communication can be suitably performed. An electromagnetic wave of 13.56 MHz is mainly used for communication of an RFID (Radio Frequency IDentification) tag, for example, and can be suitably communicated using the RFID tag in the vicinity of a metal member . Moreover, the imaginary part ε ″ of the complex dielectric constant ε is small, and eddy currents are generated when the magnetic flux passes through the shield layer, thereby preventing the occurrence of problems that interfere with wireless communication. to prevent becomes enough, it is possible to realize a suitable wireless communication environment. it is possible to absorb electromagnetic waves of 1 00MHz～1GHz Furthermore, with respect to electromagnetic waves of 100 MHz to 1 GHz, unnecessary radiation noise or the like Therefore, the loss of the 13.56 MHz electromagnetic wave used for communication can be reduced, and the unnecessary 100 MHz to 1 GHz electromagnetic wave can be absorbed and more appropriately communicated.

Further, according to the present invention, the flat soft magnetic metal powder is densely dispersed in the polymer in an oriented state without causing shape deformation including distortion and bending, thereby forming a shield layer. Therefore , a magnetic shield sheet for tags that achieves the above-described excellent effects can be realized.

In addition, according to the present invention, by ensuring insulation with a volume resistivity value of 10 ⁶ Ωcm or more, generation of eddy currents is suppressed, and electromagnetic wave shielding properties that reflect radiation noise are not imparted. Thus, a suitable tag magnetic shield sheet can be realized.

In addition, according to the present invention, it is possible to realize a magnetic shield sheet for tags that can be used in a wide range of applications with few restrictions on installation locations.

According to the present invention, it is possible to realize a tag magnetic shield sheet that has high thermal conductivity and can be used in the vicinity of a heat source.

Further, according to the present invention, the magnetic shield sheet for tags can be suitably used as a material constituting the flame retardant article or attached to the article.

Further, according to the present invention, when used by being attached to an article, the tag can be attached and attached to the article using the adhesiveness, and the tag magnetic shield sheet can be easily attached to the article.

Further, according to the present invention, it is possible to realize a tag that can be suitably transmitted / received by an antenna element even if it is provided near a metal member.

FIG. 1 is a simplified cross-sectional view showing a tag magnetic shield sheet (hereinafter simply referred to as “magnetic shield sheet”) 10 according to an embodiment of the present invention. The magnetic shield sheet 10 is a sheet used to shield at least a magnetic field. In the present embodiment, the magnetic shield sheet 10 is used to shield an electromagnetic field formed by, for example, an electromagnetic wave. In other words, in the present embodiment, the magnetic shield sheet 10 is used to shield electromagnetic waves. The electromagnetic wave to be shielded may be, for example, 13.56 MHz or 900 MHz, but is 13.56 MHz in the present embodiment.

  The magnetic shield sheet 10 is configured in a laminate in which a shield layer 11 and an adhesive layer 12 are laminated. The shield layer 11 is a layer for shielding at least a magnetic field, in this embodiment, an electromagnetic field and shielding an electromagnetic wave. The pressure-sensitive adhesive layer 12 is a layer for sticking the magnetic shield sheet 10 including the shield layer 11 to an article using the sticking force.

Shielding layer 11, the real part of the complex relative permeability mu mu 'is made of a large and the imaginary part mu "is less material of the complex relative permeability mu. Specifically, the real of the complex relative permeability mu of the shield layer 11 The part μ ′ is 30 or more, preferably 60 or more, the imaginary part μ ″ of the complex relative permeability is 6 or less, and the permeability loss term tan δ ( = μ ″ / μ ′ ) is 0. .2 or less. the real part of the complex relative permeability mu of the shield layer 11 mu 'is not preferable larger. imaginary part of the complex relative permeability mu mu "and permeability loss term tan δ (= μ" / mu ') is smaller preferably, the lower limit is equal to no, it is not a name that can be a value of 0 or less.

The shield layer 11 is made of a material having a small imaginary part ε ″ of the complex relative dielectric constant ε . Specifically, the imaginary part ε ″ of the complex relative dielectric constant ε of the shield layer 11 is 500 or less. Imaginary part of the complex relative permittivity epsilon epsilon "is smaller preferably, but just the lower limit is not, it is not a name that can be a value of 0 or less.

Specifically, such a shield layer 11 is filled with a flat soft magnetic metal powder using, for example, a non-halogen polymer or a non-halogen mixed material obtained by mixing a non-halogen polymer and another polymer as a binder. It is obtained by dispersing and orienting. In this embodiment, HNBR (hydrogenated NBR) is used, but the present invention is not limited to this. A halogen-based polymer may also be used. The material used to form these shield layers 11 is hereinafter referred to as “the present material”. When this material is compared with a sheet (hereinafter referred to as “conventional material”) in which a binder such as a polymer filled with Sendust, ferrite, and carbonyl iron used in the prior art is compared, the 13.56 MHz electromagnetic wave of this material The real part μ ′ of the complex relative permeability μ is a large value equal to or higher than the real part of the complex relative permeability of the conventional material, and the complex relative permeability μ of the present material in an electromagnetic wave of 13.56 MHz. The imaginary part μ ″ of the conventional material is a small value that is less than the imaginary part of the complex relative permeability of the conventional material. Also , the imaginary part ε ″ of the complex relative dielectric constant ε of the present material is the actual complex relative dielectric constant of the conventional material. It is a small value that is the same as or less than that of the part, and is a sufficiently low value that does not exhibit conductivity.

Here, the material constants of the present material and the conventional material with respect to electromagnetic waves having a frequency of 1 MHz to 10 GHz are compared. The material constant includes a real part μ ′ of the complex relative permeability μ, an imaginary part μ ″ of the complex relative permeability μ, a real part ε ′ of the complex relative permittivity ε, and an imaginary part ε ″ of the complex relative permittivity ε . The measurement was carried out by ring processing (φ7 × φ3) of the material and the coaxial tube method.

  FIG. 2 shows the measurement of a sheet (Example 1) formed to a thickness of 100 μm using, as the material, HNBR filled with 40 vol.% Of JEM powder (Fe—Ni—Cr—Si alloy) manufactured by Mitsubishi Materials. It is a graph which shows a result. FIG. 3 shows the measurement results of a sheet (Example 2) formed to a thickness of 100 μm using a material filled with 50 vol.% Of sendust (Fe—Si—Al alloy) resin-coated on HNBR as the present material. It is a graph. FIG. 4 is a graph showing the measurement results of a sheet (Example 3) having a thickness of 100 μm using a material in which 57 vol.% Of Sendust (Fe—Si—Al alloy) is filled in HNBR as the present material.

  FIG. 5 is a graph showing the measurement results of a sheet (Comparative Example 1) formed to a thickness of 500 μm using a material in which 50 vol.% Of ferrite is filled in chlorinated polyethylene as a conventional material. FIG. 6 is a graph showing measurement results of a sheet (Comparative Example 2) formed to a thickness of 500 μm using a material obtained by filling chlorinated polyethylene with 50 vol.% Of carbonyl iron as a conventional material. FIG. 7 is a graph showing the measurement results of a noise suppression sheet (commercial product; Comparative Example 3) formed to a thickness of 100 μm using Sendust (Fe—Si—Al alloy) as a conventional material.

2 to 4, the real part μ ′ of the complex relative permeability μ at 13.56 MHz is 30 or more, and the imaginary part μ ″ of the complex relative permeability μ is the complex relative permeability. The permeability loss term tan δ (= μ ″ / μ ′ ), which is a value divided by the real part μ ′ of the magnetic permeability μ, is 0.2 or less. Particularly, in Example 1, the real part μ ′ of the complex relative permeability μ at 61.56 MHz is 61 and the imaginary part μ ″ of the complex relative permeability μ is 3, and tan δ ( = μ ” / μ ′) is 0. .05.

On the other hand, in Comparative Example 1 and Comparative Example 2 shown in FIGS. 5 and 6, the lower limit frequency is 100 MHz, but the real part μ ′ of the complex relative permeability μ is less than 10, and lower than that. However, the behavior is shown in which the real part μ ′ of the complex relative permeability μ does not increase. In Comparative Example 3 shown in FIG. 7, the real part μ ′ of the complex relative permeability μ at 13.56 MHz is as large as 69, but the imaginary part μ ″ of the complex permeability μ is 33 and the permeability loss term tan δ ( = Μ ″ / μ ′ ) is a large value of 0.48. In each of these Comparative Examples 1 to 3, the magnetic shield sheet in the present invention, specifically, a magnetic shield material for a metal-compatible RFID tag (also called a magnetic yoke) is insufficient.

The difference in performance between Examples 1 to 3 and Comparative Examples 1 to 3 is due to the following reason. The first reason is that each of Examples 1 to 3 differs from Comparative Examples 1 and 2 in that a flat soft magnetic metal (JEM powder or Sendust) is used. The second reason is that in each of Examples 1 to 3, the flat soft magnetic metal shape was not dispersed (distorted, bent, etc.), and was closely dispersed and oriented. This is because it is different from 3. The third reason is that in each of the first to third embodiments, the frequency at which the real part μ ′ of the complex relative permeability μ of the sheet decreases is increased (100 MHz or more) to increase the complex relative permeability of 13.56 MHz. This is because it is different from Comparative Example 3 in that the imaginary part μ ″ of the magnetic susceptibility μ is lowered (realized by examining the blending method and the metal composition ratio).

In each of Examples 1 to 3 using the present material in combination of the above three reasons, preferable specific material constants μ ′, μ ″, ε ′, ε ″ can be obtained. The general noise suppression sheet is devoted to 1 and 2 above, and is designed to increase both the real part μ ′ and the imaginary part μ ″ of the complex relative permeability μ at each frequency. In particular, at a specific frequency (13.56 MHz) , the real part μ ′ of the complex relative permeability μ is high but the imaginary part μ ″ is low. In particular, the results of Example 1 are not easily obtained from conventional materials.

  The pressure-sensitive adhesive layer 12 is made of an adhesive material such as No. Nitto Denko Corporation. It consists of giving 500. By providing this pressure-sensitive adhesive layer 12, adhesiveness is imparted to at least one surface portion of the magnetic shield sheet 10. Such a pressure-sensitive adhesive layer 12 is laminated on one side in the thickness direction of the shield layer 11 to constitute the magnetic shield sheet 10.

  The magnetic shield sheet 10 has an overall thickness dimension T10 of 10 μm or more and 500 μm or less. Thus, the magnetic shield sheet 10 is formed with a small thickness dimension T10, and the shield layer 11 and the pressure-sensitive adhesive layer 12 (hereinafter, these layers are collectively referred to as “each layer 11, 12”) as described above. Made of material and flexible. Therefore, the magnetic shield sheet 10 can be freely deformed.

  In addition, in the magnetic shield sheet 10, for example, a flame retardant or a flame retardant aid is added to at least one of the layers 11 and 12. This imparts flame retardancy to the magnetic shield sheet 10. For example, an electronic device such as a mobile phone may be required to have flame retardancy for an interior polymer material.

  The flame retardant for obtaining such flame retardancy is not particularly limited. For example, phosphorus compounds, boron compounds, bromine flame retardants, zinc flame retardants, nitrogen flame retardants, hydroxide series Flame retardants, metal compound flame retardants, and the like can be used as appropriate. Examples of phosphorus compounds include phosphate esters and titanium phosphate. Examples of the boron compound include zinc borate. Examples of brominated flame retardants include hexabromobenzene, hexabromocyclododecane, decabromobenzyl phenyl ether, decabromobenzyl phenyl oxide, tetrabromobisphenol, ammonium bromide and the like. Examples of the zinc-based flame retardant include zinc carbonate, zinc oxide, and zinc borate. Examples of nitrogen-based flame retardants include triazine compounds, hindered amine compounds, or melamine compounds such as melamine cyanurate and melamine anidine compounds. Examples of the hydroxide flame retardant include magnesium hydroxide and aluminum hydroxide. Examples of the metal compound flame retardant include antimony trioxide, molybdenum oxide, manganese oxide, chromium oxide, and iron oxide.

  In this example, a flame retardant chemical in which decabromodiphenyl oxide and antimony trioxide are mixed, for example, the trade name “Polysafe FCT-5” sold by Ajinomoto Fine Technology Co., Ltd. is used for the polymer material 100. The evaluation of UL94V0 was achieved by adding 30 chemicals (weight ratio). The magnetic shield sheet 10 can be suitably used as a material constituting such an article or mounted on the article. For example, it can be suitably used by being mounted on an article used in a space where it is desired to prevent combustion and generation of gas accompanying it, such as an apparatus in an aircraft, a ship, and a vehicle.

Moreover, the magnetic shield sheet 10 has electrical insulation. Specifically, the volume specific resistance value of the magnetic shield sheet 10 is 10 ⁶ Ωcm or more because each of the layers 11 and 12 is made of the material as described above. The volume specific resistance value of the shield layer 11 is preferably as large as possible. Therefore, the maximum value that can be realized is the upper limit value of the volume resistivity. Thus has high volume resistivity, it has an electrical insulating property.

  The magnetic shield sheet 10 has heat resistance. Specifically, the heat-resistant temperature of the magnetic shield sheet 10 when a crosslinking agent is added to rubber or a resin material is 150 ° C., and the magnetic shield sheet 10 has characteristics until the temperature exceeds at least 150 ° C. Does not change.

  FIG. 8 is a cross-sectional view showing the tag 15 including the magnetic shield sheet 10 in a simplified manner. The tag 15, which is an electronic component, includes an antenna element 16 for transmitting and receiving an electromagnetic wave signal (sometimes referred to as an “electromagnetic wave signal”) and an integrated circuit (IC) 17 electrically connected to the antenna element 16. The magnetic shield sheet 10 is further provided on the tag.

  The antenna element 16 serving as an antenna means is a loop antenna formed in a loop shape along the virtual plane 18. The virtual surface 18 may be a flat surface or a curved surface, but is a flat surface in the present embodiment. The antenna element 16 can transmit at least an electromagnetic wave signal toward one side with respect to the virtual plane 18 and can receive an electromagnetic wave signal coming from one side with respect to the virtual plane 18. Specifically, the antenna element 16 transmits an electromagnetic wave signal in a transmission / reception direction A that is perpendicular to the virtual surface 18 and faces one side of the virtual surface 18, and receives an electromagnetic wave signal that arrives from the transmission / reception direction A. Can do.

  The IC 17 has at least a storage unit and a control unit. Information can be stored in the storage unit, and the control unit can store information in the storage unit or read information from the storage unit. In response to a command represented by the electromagnetic wave signal received by the antenna element 16, the IC 17 stores information in the storage unit or reads information stored in the storage unit and outputs a signal representing the information to the antenna element 16. To give.

  For example, an electromagnetic wave signal representing information to be stored in advance (hereinafter referred to as “main information”) and information instructing to store the main information (hereinafter referred to as “storage command information”) from the information management device, When received by the antenna element 16, an electrical signal representing main information and storage command information is provided from the antenna element 16 to the IC 17. The IC tag 17 causes the control unit to store main information in the storage unit based on the storage command information.

  An electromagnetic wave signal representing information (hereinafter referred to as “transmission command information”) for instructing to transmit information (hereinafter referred to as “storage information”) stored in the storage unit is received by the antenna element 16 from the information management device. Then, an electric signal representing transmission command information is given from the antenna element 16 to the IC 17. As for IC tag 17, a control part reads the information (memory | storage information) memorize | stored in a memory | storage part based on transmission command information, and gives the electrical signal showing the memory | storage information to the antenna element 16. FIG. As a result, an electromagnetic wave signal representing stored information is transmitted from the antenna element 16.

  Thus, the tag 15 is an electronic component that transmits and receives an electromagnetic wave signal using the antenna element 16. The tag 15 may be a battery-driven tag that is driven by a built-in battery, or may be a batteryless tag that returns an electromagnetic wave signal using the energy of the received electromagnetic wave signal.

  The magnetic shield sheet 10 is used so that such a tag 15 can be used in the vicinity of the metal member 19. The magnetic shield sheet 10 is provided on the side opposite to the transmission / reception direction A with respect to the antenna element 16, and thus on the other side with respect to the virtual surface 18. The magnetic shield sheet 10 is provided with the adhesive layer 12 disposed on the opposite side of the antenna element 16 and the IC 17 from the shield layer 11.

  Although simplified in FIG. 8, the antenna element 16 and the IC 17 are packaged by being mounted on a flexible tape, and the magnetic shield sheet 10 is attached thereto. Are stacked. In attaching the magnetic shield sheet 10 to the package on which the antenna element 16 and the IC 17 are mounted, for example, an adhesive is used.

  The tag 15 including the magnetic shield sheet 10 is used by being mounted on, for example, a metal member 19. The tag 15 is provided so that the magnetic shield sheet 10 is disposed closer to the metal member 19 than the antenna element 16 so that the magnetic shield sheet 10 is interposed between the antenna element 16 and the metal member 19. It is done. The pressure-sensitive adhesive layer 12 of the magnetic shield sheet 10 faces the metal member 19, and the pressure-sensitive adhesive layer 12 is attached and attached to the metal member 19.

  The magnetic shield sheet 10 has the shield layer 11 as described above. The electromagnetic field is shielded by the shield layer 11 and the electromagnetic field of one of the two regions partitioned by the magnetic shield sheet 10 is used. Can be prevented from leaking to the other region, and the energy of the electromagnetic field in one region can be prevented from being transmitted to the other region. The electromagnetic field that can be shielded includes, of course, an electromagnetic field formed by an electromagnetic wave, and therefore the electromagnetic wave that forms this electromagnetic field can be shielded.

To be specific, the shield layer 11, since made of a real part mu 'is large material of the complex relative magnetic permeability mu, the provision of the shield layer 11 in the magnetic field is transmitted from the antenna element 16 in FIG. 8 for example As shown in the example of the electric field due to electromagnetic waves, the magnetic lines of force 20 pass through the shield layer 11 in a concentrated manner, and do not pass through or difficult to pass through the metal member 19 existing in the vicinity. Thus, the magnetic shield sheet 10 is used to shield the magnetic field, and the magnetic field in the region where the antenna element 16 which is one region partitioned by the magnetic shield sheet 10 is provided is the metal member which is the other region. It can prevent leaking to the area | region in which 19 is provided.

  When the antenna element 16 is provided at a position similar to the position shown in FIG. 8, if the magnetic shield sheet 10 is not provided, the magnetic field lines of the magnetic field due to the transmitted electromagnetic waves are, for example, as shown by the virtual line 21 in FIG. In addition, it passes through the metal member 19. When the magnetic lines of force pass through the metal member 19 in this way, an eddy current is generated in the metal member 19 with the change of the magnetic field, and heat is generated. Thus, the energy of the magnetic field is converted into heat energy, and the energy of the magnetic field is absorbed. On the other hand, by shielding the magnetic field using the magnetic shield sheet 10, the energy of the magnetic field opposite to the metal member 19 with respect to the magnetic shield sheet 10 is prevented from being absorbed by the metal member 19. Can be removed. Therefore, the magnetic member 19 absorbs the energy of the magnetic field formed by the electromagnetic wave transmitted and received by the antenna element 16 on the side of the antenna element 16 that is opposite to the metal member 19 with respect to the magnetic shield sheet 10. It is prevented.

Further, since the shield layer 11 is made of a material having a small imaginary part μ ″ of the complex relative permeability μ, even if magnetic flux passes through the shield layer 11, energy loss in the shield layer 11 due to the passage is reduced. As a result, even if the magnetic lines of force pass through the shield layer 11 in a concentrated manner, the shield layer 11 itself is prevented from losing energy of the magnetic field. Further, absorption of magnetic field energy by the metallic member 19 existing in the vicinity can be prevented, loss by the self can be suppressed to be small, and attenuation of magnetic field energy can be made as small as possible.

  By interposing such a magnetic shield sheet 10 between the antenna element 16 and the metal member 19 as described above, the energy of the electromagnetic field due to the electromagnetic wave signal transmitted and received by the antenna element 16 is made of metal. Absorption by the member 19 is prevented. In addition, the magnetic shield sheet 10 itself for preventing the influence of the metal member 19 has a small magnetic loss and dielectric loss. Therefore, the antenna element 16 can transmit and receive a long distance suitably. Therefore, even when the tag 15 is provided in the vicinity of the metal member 19, information can be wirelessly communicated between the information management apparatus and the tag 15, and the electromagnetic wave signal transmitted from the information management apparatus can be transmitted. The information to be represented can be stored in the tag 15, and the information stored in the tag 15 can be read out by the information management device.

  Thus, by using the magnetic shield sheet 10, an electronic component using the antenna element 16 is attached to the metal member 19, for example, and is provided in the vicinity of the metal member 19. An electronic component can be used in a state where transmission and reception can be realized. Therefore, for example, the tag 15 as described above is attached to a beverage 22 containing a beverage in a metal container which is a metal member 19 as shown in FIG. Can be used. Further, the tag 15 is incorporated in an electronic device 23 such as a mobile phone device in which many metal members 19 such as a substrate as shown in FIG. 10 are used, for example, for the purpose of merchandise management or user authentication. Can be used. Thus, the wide use of the tag 15 can be secured, and the highly convenient tag 15 can be realized.

As shown in FIG. 8 , according to the present invention, it functions as an RFID metal-compatible magnetic shield sheet at 13.56 MHz, and has an effect of suppressing (absorbing) unnecessary radiation noise and the like at other frequencies (1 GHz).

Further, the present invention is characterized in that the real part μ ′ of the complex relative permeability μ from 100 MHz to 1 GHz is 7 or more and the imaginary part μ ″ of the complex relative permeability μ is 7 or more.

According to the present invention, it functions as an RFID metal-compatible magnetic shield sheet at 13.56 MHz, and has a high suppression effect (absorption) of unwanted radiation noise at other wide frequency ranges (100 MHz to 1 GHz). Specifically, the real part μ ′ of the complex relative permeability μ at 100 MHz in Example 1 is 35, the imaginary part μ ″ is 19, and the real part μ ′ of the complex relative permeability μ at 1 GHz is 12. 4 and the imaginary part μ ″ is 14 , indicating that the noise suppression effect is used together.

  Moreover, since the magnetic shield sheet 10 has flexibility as described above, it can be freely deformed. Thereby, there are few restrictions on an installation place and it can be used for a wide use. For example, when it is used by being attached to an article, it can be provided following the shape of the article. For example, as shown in FIG. 9, it can be attached to the surface of a cylindrical container (corresponding to the metal member 19) in accordance with the shape of the surface. Can be reduced, and the mounting operation can be facilitated. When used as the tag 15, the material of the other configuration can be appropriately selected so that the tag 15 has a flexible configuration as a whole, so that the tag 15 can be attached following the cylindrical surface. It becomes like this.

  In addition, since the magnetic shield sheet 10 is provided with adhesiveness on at least one surface portion, when attached to an article, the magnetic shield sheet 10 can be attached to the article using the adhesiveness. Thus, the magnetic shield sheet 10 can be easily attached to the article. Therefore, the operation | work for utilizing the magnetic shielding sheet 10 and an electronic component provided with it can be made easy.

The magnetic shield sheet 10 has heat resistance and electrical insulation as described above. With regard to heat resistance, it may be used at 120 ° C. or 130 ° C. particularly in automobile applications, and it is required that it can be used without degradation of performance even at that temperature. The heat resistance can be realized by adding a crosslinking material and crosslinking the binder. In this case, it is of course possible to realize heat resistance at a higher temperature (for example, 200 ° C.) by appropriately combining the kind of the binder used and the crosslinking material. Further, by covering the soft magnetic metal powder with an organic and inorganic insulating material as a binder, the electrical insulation of the magnetic shield sheet 10 can be improved without direct contact with the soft magnetic metal dispersed in the sheet. Can do. If electricity is conducted, an eddy current is generated in itself and the magnetic energy is attenuated. Furthermore, since the circuit and the plating casing (ground) are arranged in close proximity, if the magnetic shield sheet 10 has conductivity, it will be conducted through it, which will hinder the operation. And the volume resistivity of the magnetic shield sheet 10 in order to prevent these have achieved more than 10 ⁶ Omega cm.

  The above-described embodiment is merely an example of the present invention, and the configuration can be changed. For example, the stacked configuration may be changed. Specifically, as shown by a virtual line in FIG. 1, the second pressure-sensitive adhesive layer 30 may be provided on the side opposite to the pressure-sensitive adhesive layer 12 with respect to the shield layer 11. When such a magnetic shield sheet 10 is used for the tag 15, when the magnetic shield sheet 10 is attached to a package on which the antenna element 16 and the IC 17 are mounted to configure the tag 15, a separate adhesive is used. Even if it does not use, it becomes possible to stick using the second adhesive material layer 30, and the work becomes easy. Thus, the installation and mounting work of the magnetic shield sheet 10 can be facilitated such that the magnetic shield sheet 10 can be easily incorporated into an electronic component.

  Further, the adhesive layer 12 may be used for attaching the magnetic shield sheet 10 to a package on which the antenna element 16 and the IC 17 are mounted when the adhesive layer 12 is incorporated into the tag 15. In this case, as long as the second pressure-sensitive adhesive layer 30 is provided, the second pressure-sensitive adhesive layer 30 may be attached to the article, or the second pressure-sensitive adhesive layer 30 is not provided. For example, it may be attached to the article using an adhesive. Moreover, the structure which adds an adhesive to the shield layer 11, and provides adhesiveness to the surface may be sufficient, without forming the adhesive layers 12 and 30.

  Further, the means for imparting flame retardancy may be another configuration instead of the configuration in which the flame retardant is added. Further, the minimum performance required for the magnetic shield sheet 10 is a performance for shielding a magnetic field, and the other performance is not an essential requirement and may not have a configuration.

The application of the magnetic shield sheet 10 is not limited to electronic components, and can be widely used in applications where there is a requirement to shield at least a magnetic field. Of course, the electronic component is not limited to the tag 15. Further, the tag 15 may be used for an article having a metal member 19 other than the aforementioned article. For example, the electronic device is not limited to a mobile phone device, but may be a PDA, a notebook personal computer, or the like.
Configuration changes other than these examples may be used.

It is sectional drawing which simplifies and shows the magnetic shielding sheet 10 for tags of one Embodiment of this invention. 6 is a graph showing measurement results of material constants (ε ′, ε ″, μ ′, μ ″) of Example 1. 6 is a graph showing measurement results of material constants (ε ′, ε ″, μ ′, μ ″) of Example 2. 10 is a graph showing measurement results of material constants (ε ′, ε ″, μ ′, μ ″) of Example 3. 6 is a graph showing measurement results of material constants (ε ′, ε ″, μ ′, μ ″) of Comparative Example 1. 10 is a graph showing measurement results of material constants (ε ′, ε ″, μ ′, μ ″) of Comparative Example 2. 10 is a graph showing measurement results of material constants (ε ′, ε ″, μ ′, μ ″) of Comparative Example 3. It is sectional drawing which simplifies and shows the tag 15 provided with the magnetic shielding sheet 10. FIG. It is a perspective view which shows the beverage 22 with which the tag 15 is mounted | worn. It is a perspective view which shows the electronic apparatus with which the tag 15 is incorporated. It is sectional drawing which simplifies and shows the tag 1 which is a prior art. It is sectional drawing which simplifies and shows the tag 1A which is another prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Magnetic shield sheet 11 Shield layer 12 Adhesive layer 15 Tag 16 Antenna element 17 IC
19 Metal Member 20 Magnetic Field Line 22 Beverage 23 Electronic Device

Claims (8)

An antenna element for transmitting and receiving an electromagnetic wave signal having a frequency of 13.56 MHz, and an integrated circuit electrically connected to the antenna element and transmitting a signal from the antenna element in response to a signal received by the antenna element A tag magnetic shield sheet provided between the antenna element and the metal member when using the tag provided in the vicinity of the metal member,
Frequency Ri imaginary part mu "is 6 der following real part mu 'is not less than 30 and the complex relative permeability mu of the complex relative permeability mu at 13.56MHz electromagnetic waves,
The imaginary part ε ″ of the complex relative dielectric constant ε in an electromagnetic wave having a frequency of 13.56 MHz is 500 or less,
For a tag comprising a shield layer having a real part μ ′ of a complex relative permeability μ of 7 or more and an imaginary part μ ″ of a complex relative permeability μ of 7 or more in an electromagnetic wave having a frequency of 100 MHz to 1 GHz Magnetic shield sheet. The shield layer is made of a material in which a flat soft magnetic metal powder is mixed with a polymer,
2. The magnetic shield sheet for a tag according to claim 1, wherein the soft magnetic metal powder is densely dispersed in an oriented state without causing shape deformation including distortion and bending. The magnetic shield sheet for tags according to claim 1 or 2, wherein the volume resistivity value is 10 ⁶ Ωcm or more. It has flexibility, The magnetic shield sheet for tags as described in any one of Claims 1-3 characterized by the above-mentioned. The magnetic shield sheet for tags according to any one of claims 1 to 4 , wherein thermal conductivity is imparted. 6. The magnetic shield sheet for tags according to any one of claims 1 to 5 , wherein flame retardancy is imparted. The magnetic shield sheet for tags according to any one of claims 1 to 6 , wherein at least one surface portion is provided with adhesiveness. An antenna element for frequency to transmit and receive electromagnetic signals 13.56 MHz,
An integrated circuit electrically connected to the antenna element and transmitting a signal from the antenna element in response to a signal received by the antenna element;
A tag comprising the tag magnetic shield sheet according to claim 1 .

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