JP2007295558A - Antenna transmission improving sheet body and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antenna transmission improving sheet body capable of intensively passing a magnetic field without losing magnetic field energy generated by an electromagnetic wave having a communication frequency and shielding noise. <P>SOLUTION: This antenna transmission improving sheet body 10 comprises a shield layer 11 and a conductive layer 12. The shield layer 11 has desirable material constants μ' and μ" and a surface resistance ratio of 10<SP>4</SP>Ω/sq. or higher for an electromagnetic wave having a communication frequency. In addition, this antenna transmission improving sheet object 10 has the electric field shielding performance of 20 dB or more and a magnetic field shieldability of 10 dB or larger for the electromagnetic wave having the communication frequency. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an antenna communication improving sheet body having an electromagnetic wave shielding effect and a magnetic field shielding effect, and an electronic apparatus using the same.

  Specific examples of RFID (Radio Frequency Identification) technology include RFID tags (RF tags, IC tags), non-contact IC cards, mobile terminals equipped with RFID functions, readers, readers / writers that communicate wirelessly with tags, etc. Including electronic equipment is used. There are the following two types of communication means for RFID wireless communication. One is an electromagnetic induction system in which communication is performed using a coil-to-coil combination, and the frequency is a 125 kHz band, a band less than 135 kHz, a 13.56 MHz band, or the like. The other one is a radio wave system, and the frequency is 433 MHz band, UHF (ultra high frequency) band (860 MHz to 960 MHz), 2.4 GHz band, or the like. The frequency mainly used for the non-contact IC card is the 4.91 MHz band for the contact type and the 13.56 MHz band 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.

  As shown in FIG. 11, the tag includes an antenna that transmits and receives an electromagnetic wave signal, and an integrated circuit (IC) that processes a signal transmitted and received by the antenna. FIG. 11 shows an example of an antenna coil that communicates by electromagnetic induction. A state in which the IC chip 2 and the antenna coil 1 are combined on the substrate 3 or a package in which the IC chip 2 and the antenna coil 1 are combined on the substrate 3 is called a tag inlet. The tag is a communication member including an antenna, and includes the tag inlet. Further, the tag is a communication partner of a reader such as a reader or a reader / writer, and may be distinguished from the reader. However, in the present invention, when the tag has a function as a reader and a reader / writer, Communication improvement works in common and is included in the tag. The tag is configured to transmit the information stored in the IC upon receiving a request signal from the reading device, in other words, the information held in the tag can be read by the reading device. Is done. This tag (tag inlet) is built in, for example, a plastic card or the like, and is used for entrance / exit management or the like as a non-contact IC card.

  With the spread of RFID technology, it is required to read a plurality of standard tags (tag inlets) using electromagnetic waves of the same communication frequency with one reading device, and a plurality of reader / writers are mounted on one reading device. As a result, for example, RFID systems of different standards having the same frequency have begun to be used in the immediate vicinity. In addition, in pursuit of miniaturization of the reader itself, electronic components are arranged with high density in the reader. As a result, when the tag (tag inlet) communicates with the reader, unnecessary electromagnetic waves called noise from electronic components and cables and communication radio waves with other readers are communicated between the tag (tag inlet) and the reader. Adversely affect. Specifically, the electromagnetic wave radiated from the electronic component has an adverse effect on the antenna of the tag (tag inlet), or the electromagnetic wave arriving at the electronic component has an adverse effect on the antenna of the tag (tag inlet). This causes a change in the resonance frequency, or the communication wave is surpassed by other-wave interference, and communication with the reading apparatus cannot be performed. In addition, the magnetic field generated from the electronic component becomes noise, which may adversely affect the tag (tag inlet) antenna and the reader antenna. Therefore, it is necessary to shield the antenna from such unnecessary electromagnetic waves and magnetic fields.

  As a conventional method of shielding a tag (tag inlet) from electromagnetic waves and magnetic fields, there is a method of covering the entire tag with a covering device that shields radio waves. Such a covering tool is described in Patent Document 1, for example. Patent Document 1 describes a covering that covers the entire tag with a covering portion that shields from radio waves. This covering tool can expose a tag (tag inlet) from the covering portion or return it to the covering portion.

  In addition, as a method of shielding an article such as an electronic component from electromagnetic waves and magnetic fields, there is a method of covering the article with a metal foil made of a highly conductive metal, such as an aluminum foil or a copper foil.

JP 2005-86244 A

According to Patent Document 1, in a covering state in which the entire tag (tag inlet) is covered with a covering device that shields radio waves, the tag (tag inlet) is shielded from electromagnetic waves and magnetic fields, and the tag (tag inlet) is exposed from the covering device. In the exposed state, communication between the tag (tag inlet) and the reading device is enabled.
However, in an exposed state where communication between the tag (tag inlet) and the reader is possible, the antenna coil cannot be shielded from electromagnetic waves and magnetic fields at all, and noise is generated between the tag (tag inlet) and the reader. Cannot solve the problem of adversely affecting

  Further, when the metal foil is formed so as to cover the antenna coil so as not to hinder the wireless communication of the tag (tag inlet), the tag antenna can be shielded from electromagnetic waves and magnetic fields. However, when a metal member such as a metal foil is present in the vicinity of the antenna coil, the magnetic field lines of the magnetic field formed by the electromagnetic wave signal transmitted and received by the antenna coil are affected by the metal. The magnetic field component flows near the metal surface, which causes eddy currents on the metal member surface. The generation of eddy current in this way causes eddy current loss in which the magnetic field is lost energetically. Further, since the magnetic field induced by the eddy current is a demagnetizing field with respect to the magnetic field for communication, the magnetic fields cancel each other, and the magnetic field is lost energetically. Furthermore, the self-inductance of the antenna coil changes due to the influence of the metal, and the resonance frequency of the antenna coil changes, so that transmission / reception becomes impossible.

  Therefore, it is possible to shield the antenna coil of the tag (tag inlet) from electromagnetic waves and magnetic fields, but since the communication between the tag (tag inlet) and the reader cannot be performed, noise is generated between the tag (tag inlet) and the tag (tag inlet). The problem of adversely affecting communication with the reading device cannot be solved.

  The objective of this invention provides the sheet | seat body which can concentrate and let a magnetic field pass through without losing the energy of the magnetic field formed with the electromagnetic wave of a communication frequency, and also can shield a noise. Specifically, noise is low-frequency electromagnetic noise or a magnetic field generated from a magnet. Furthermore, by using this sheet body, an electronic device capable of suitably performing wireless communication using electromagnetic waves having a communication frequency while shielding noise is provided.

In the present invention, the real part μ ′ of the complex relative permeability is 30 or more and the imaginary part μ ″ of the complex relative permeability is divided by the real part μ ′ of the complex relative permeability μ with respect to the communication frequency electromagnetic wave. The value tan δ _μ is 0.2 or less, and is composed of a shield layer and a conductor layer having a surface resistivity of 10 ⁴ Ω / □ or more,
An antenna communication improving sheet having an electric field shielding property of 20 dB or more and a magnetic field shielding property of 10 dB or more against electromagnetic waves having the communication frequency.

  Further, the present invention is characterized by being laminated with a shield layer / conductor layer or laminated with a shield layer / conductor layer / shield layer.

  In the invention, it is preferable that the communication frequency is 100 kHz or more and 30 GHz or less.

  In the invention, it is preferable that the conductor layer has a magnetic field shielding property of 30 dB or more against electromagnetic waves having the communication frequency.

In the present invention, the shield layer is made of a material in which a flat soft magnetic metal powder is mixed in a binder,
The soft magnetic metal powder is contained in an amount of 20% by volume or more based on the binder and is dispersed in an oriented state.

In the invention, it is preferable that the conductor layer contains a magnetic metal.
In the invention, it is preferable that the magnetic metal is one or more metals or alloys selected from iron, cobalt, and nickel.

  In the present invention, the thickness of the antenna communication improving sheet is 1.0 μm or more and 10 mm or less.

Further, the present invention is characterized in that flame retardancy is imparted.
The present invention also provides antenna means for transmitting and receiving electromagnetic wave signals;
An electronic apparatus comprising the antenna communication improving sheet laminated on a side opposite to a transmission / reception direction with respect to the antenna means.

  In the invention, it is preferable that the antenna communication improving sheet is disposed so as to cover the antenna means while ensuring communication by the antenna means.

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

The shield layer has a real part μ ′ of complex relative permeability as large as 30 or more for electromagnetic waves of communication frequency, and an imaginary part μ ″ of complex relative permeability is divided by a real part μ ′ of complex relative permeability. The value tan δ _μ is 0.2 or less, and the imaginary part μ ″ of the complex relative permeability is smaller than the real part μ ′ of the complex relative permeability. By doing so, it is possible to make it easier for magnetic lines of force (magnetic flux) to pass through the shield layer against the magnetic field formed by electromagnetic waves at the communication frequency, and to prevent loss of magnetic field energy thereon. it can. Therefore, such a shield layer can concentrate and pass electromagnetic waves having a communication frequency so as not to leak while suppressing loss of energy.

Further, when the shield layer has a low surface resistivity and exhibits conductivity, an eddy current is generated when the magnetic flux passes through the shield layer. When eddy currents are generated in this way, for example, when used for securing a wireless communication environment, it becomes an obstacle to wireless communication by attenuating magnetic flux. On the other hand, when the surface resistivity is high, an eddy current hardly occurs at the shield layer, particularly the surface portion of the shield layer. The surface resistivity of the shield layer is as high as 10 ⁴ Ω / □ or higher, thereby suppressing the generation of eddy currents in the shield layer.

  The sheet for improving antenna communication is provided with a conductor layer. The conductor layer, combined with the shield layer, has a high electric field shielding property of 20 dB or more and a high magnetic field shielding property of 10 dB or more against electromagnetic waves of the communication frequency, and therefore can shield incoming electromagnetic waves and magnetic fields. .

  From the above, the antenna communication improvement sheet body can shield noise such as unnecessary electromagnetic waves and magnetic fields coming from the conductor layer side in the case of wireless communication using electromagnetic waves of communication frequency, By the layer, the magnetic field for communication can be concentrated and passed without losing the energy of the magnetic field formed by the electromagnetic wave having the communication frequency coming from the shield layer side. Therefore, by using this antenna communication improving sheet, radio communication can be suitably performed using electromagnetic waves having a communication frequency while shielding noise.

  Moreover, according to this invention, it is preferable to laminate | stack with a shield layer / conductor layer, or to laminate | stack with a shield layer / conductor layer / shield layer.

  Moreover, according to this invention, a communication frequency is 100 kHz or more and 30 GHz or less, and it can communicate suitably by using the electromagnetic wave of this communication frequency. For example, it can be used for communication of an RFID tag.

  Further, according to the present invention, it is preferable that the conductor layer has a magnetic field shielding property of 30 dB or more with respect to electromagnetic waves having a communication frequency, since noise coming from the conductor layer side can be further shielded.

  According to the present invention, the shield layer is made of a material in which a flat soft magnetic metal powder is mixed in a binder, and the soft magnetic metal powder is contained in an amount of 20% by volume or more based on the binder. Is distributed. By doing so, it is possible to realize a sheet body for improving antenna communication that achieves an excellent effect that the magnetic field can be concentrated and passed without losing the energy of the magnetic field formed by the electromagnetic wave of the communication frequency. it can.

  In addition, electronic devices generate not only radio waves but also low-frequency magnetic fields. It is difficult to shield such a low-frequency magnetic field only by a conductor layer such as a metal foil. In order to shield, a considerable thickness, for example, about 3 mm in the case of an aluminum foil is required. It is. A metal foil having such a thickness that can shield such a magnetic field is difficult to process, and when used to coat a tag, the tag coated with the metal foil has great flexibility and flexibility. It will be damaged. Furthermore, RFID communication cannot be performed through the metal foil.

  Such a shield layer has high flexibility and flexibility, and has an effect of shielding a low-frequency magnetic field. Therefore, since the antenna communication improving sheet body is provided with not only the conductor layer but also the shield layer, it has high flexibility and flexibility and can shield a low-frequency magnetic field.

  According to the invention, the conductor layer includes a magnetic metal. By doing so, the magnetic shielding property of the conductor layer can be enhanced, and the shielding property of noise coming from the conductor layer side can be further enhanced.

  According to the invention, the magnetic metal is preferably made of one or more metals or alloys selected from iron, cobalt and nickel. By doing so, the magnetic shielding property of a conductor layer can be improved more and it is preferable.

  Moreover, according to this invention, the thickness of the sheet | seat body for antenna communication improvement is 1.0 micrometer or more and 10 mm or less. By doing so, noise arriving from the conductor layer side can be shielded while ensuring sufficient flexibility and flexibility, and wireless communication is suitably performed using electromagnetic waves having a communication frequency arriving from the shield layer side. be able to. Furthermore, a low frequency magnetic field can be shielded.

  According to the invention, the antenna communication improving sheet body is provided with flame retardancy. An electronic device such as a mobile phone may be required to have flame retardancy for an internal polymer material. The sheet body can be suitably used as a material constituting such an article or attached to the article.

  Moreover, according to this invention, it is an electronic device containing the antenna means for transmitting / receiving an electromagnetic wave signal, and the sheet | seat body for antenna communication improvement. The antenna communication improving sheet body is laminated on the side opposite to the transmission / reception direction with respect to the antenna means. By doing so, the electronic device can shield noises such as unnecessary electromagnetic waves and magnetic fields coming from the conductor layer side, and can suitably perform wireless communication using electromagnetic waves having a communication frequency coming from the shield layer side. it can.

  Further, for example, when an electronic device such as a tag (tag inlet) is attached to an article or used in the vicinity of other electronic equipment, an antenna communication improving sheet is disposed between the antenna means and the article. As described above, since the antenna communication improving sheet can be laminated on the antenna means in advance, the resonance frequency of the antenna means can be set in advance. Therefore, a wireless communication environment can be suitably realized regardless of the material of the surface of the article to which the electronic device is attached and the presence of other electronic devices.

  According to the invention, the antenna communication improving sheet is disposed so as to cover the antenna means while ensuring communication by the antenna means. The arrangement can be selected to be completely (entire of the antenna means or RFID communication space) or partially covered. By doing so, it can arrange | position so that RFID radio | wireless communication may not be inhibited, and even if it is a sheet | seat body for antenna communication improvement of a small area, it can fully exhibit a shield property from noise. Further, the antenna communication improving sheet can secure a suitable communication environment. Therefore, the area of the sheet for improving antenna communication to be stacked can be reduced, which is preferable because the electronic apparatus can be downsized. In addition, the manufacturing cost can be reduced.

  FIG. 1 is a cross-sectional view showing a simplified antenna communication improving sheet body 10 according to the first embodiment of the present invention. The antenna communication improving sheet 10 is an antenna communication improving sheet used to concentrate and pass at least a magnetic field. In the present embodiment, for example, an electromagnetic field formed by electromagnetic waves is concentrated and passed. Used to make In other words, in the present embodiment, the antenna communication improving sheet body 10 is used to concentrate and pass electromagnetic waves. The electromagnetic wave to be concentrated and passed is an electromagnetic wave having a communication frequency. The communication frequency may be 100 kHz or more and 30 GHz or less. For example, the communication frequency may be a 13.56 MHz band, a 125 kHz band, a band less than 135 kHz, and a 4.3 MHz band.

  The antenna communication improving sheet 10 is configured by laminating a shield layer 11 and a conductor layer 12. Further, in the antenna communication improving sheet 10, the pressure-sensitive adhesive layer 13 is laminated on the conductor layer 12 side. The shield layer 11 is a layer for concentrating and passing at least a magnetic field, in this embodiment, an electromagnetic field. The conductor layer 12 is a layer for shielding noise such as incoming unnecessary electromagnetic waves and magnetic fields. The pressure-sensitive adhesive layer 13 is a layer for adhering the antenna communication improving sheet body 10 including the shield layer 11 and the conductor layer 12 to an article using an adhesive force. The essential components of the antenna communication improving sheet 10 are a shield layer 11 and a conductor layer 12, and other adhesive layers and the like are used if necessary. Between the conductor layer 12 and the shield layer 11, there may or may not be an adhesive layer, an adhesive layer, a dielectric layer, or the like as the adhesive layer 13. It is also possible to use a dielectric layer that is not sticky or adhesive. Further, the antenna communication improving sheet body 11 and the conductor layer 12 may have the same size, but are not necessarily the same.

  The shield layer 11 is made of a material having a large real part μ ′ of the complex relative permeability and a small imaginary part μ ″ of the complex relative permeability. The shield layer 11 has a larger real part μ ′ of the complex relative permeability. The lines of magnetic force (magnetic flux) concentrate and pass, and the smaller the real part μ ′ of the complex relative permeability, the harder the line of magnetic force (magnetic flux) passes.The shield layer is the imaginary part of the complex relative permeability. As μ ″ increases, the magnetic field energy is lost, and as the imaginary part μ ″ of the complex relative permeability decreases, the magnetic field energy is less likely to be lost.

Specifically, the real part μ ′ of the complex relative permeability of the shield layer 11 is as large as 30 or more, preferably 40 or more. The imaginary part μ ″ of the complex relative permeability is as small as 6 or less, preferably 3 or less. Further, it is a value obtained by dividing the imaginary part μ ″ of the complex relative permeability by the real part μ ′ of the complex relative permeability. The permeability loss term tan δ _μ (= μ ″ / μ ′) is 0.2 or less, preferably 0.1 or less, and the complex relative permeability is compared with the real part μ ′ of the complex relative permeability. The imaginary part μ ”is small. The preferred range in which the permeability loss term tan δ _μ is 0.2 or less has priority over the preferred range in which the imaginary part μ ″ is 6 or less. For example, the real part μ of the complex relative permeability at 13.56 MHz. When 'is 60 and tan δ _μ (= μ ″ / μ ′) is 0.2, the imaginary part μ ″ of the complex relative permeability is 12, which is larger than 6. In such a case, The preferred range in which tan δ (= μ ″ / μ ′) is 0.2 or less is preferentially applied, and the preferred range of the imaginary part μ ″ of the complex relative permeability is 12 or less. It is possible to make it easier for magnetic field lines (magnetic flux) to pass through the shield layer 11 with respect to the magnetic field formed by the electromagnetic wave, and to prevent loss of magnetic field energy on the magnetic layer. Layer 11 is a communication frequency A plurality of electromagnetic waves can be concentrated and passed so as not to leak while suppressing energy loss, and the real part μ ′ of the complex relative permeability of the shield layer 11 is preferably as large as possible. There is no upper limit for the real part μ ′ of the imaginary part. The imaginary part μ ″ of the complex relative permeability and the permeability loss term tan δ _μ are preferably as small as possible and equal to no lower limit, but cannot be less than zero. Therefore, 0 is the lower limit value.

Further, the shield layer 11 has a high surface resistivity. When the shield layer 11 exhibits conductivity, an eddy current is generated when the magnetic flux approaches the shield layer 11. When eddy currents are generated in this manner, for example, a magnetic flux used for securing a wireless communication environment is attenuated, thereby hindering wireless communication. On the other hand, when the surface resistivity is high, an eddy current hardly occurs in the shield layer 11. The shield layer 11 has a surface resistivity of 10 ⁴ Ω / □ or more, preferably 10 ⁶ Ω / □ or more, and can sufficiently ensure the insulation of the shield layer 11. Suppresses the generation of eddy currents. The upper limit of the surface resistivity is 10 ¹³ Ω / □ to 10 ¹⁵ Ω / □ for the polymer material, and this is the upper limit value of the surface resistivity of the shield layer 11.

  The shield layer 11 is made of a material having a small imaginary part ε ″ of the complex relative dielectric constant. The imaginary part ε ″ of the complex relative dielectric constant of the shield layer 11 is a measure of the conductivity of the shield layer 11, and the imaginary part ε ″. If the electrical conductivity is developed, an eddy current is generated when the magnetic flux passes through the shield layer 11. When the eddy current is generated in this way, The induced demagnetizing field impedes wireless communication by, for example, attenuating the magnetic flux used to improve the wireless communication environment. On the other hand, when the imaginary part ε ″ of the complex dielectric constant is small, the shield layer 11 In this configuration, eddy currents hardly occur.

  Specifically, the shield layer 11 has a real part ε ′ of a complex relative dielectric constant of 50 or more, preferably 60 or more. The imaginary part ε ″ of the complex dielectric constant is as small as 500 or less, preferably 300 or less. The imaginary part ε ″ of the complex dielectric constant is preferably as small as possible, and there is no lower limit, but it can be a value less than 0. Therefore, 0 is the lower limit value. Specifically, in the case of 13.56 MHz, when the imaginary part ε ″ of the complex relative permeability of the shield layer 11 is 500, the conductivity σ is 0.4 S / m and the resistivity ρ is 2.5 Ω · m. Since the imaginary part ε ″ of the complex relative permeability is 500 or less, the shield layer 11 has a conductivity σ of 0.4 S / m or less, a resistivity ρ of 2.5 Ω · m or more, and a low conductivity. Rate or high resistivity. In such a shield layer 11, no eddy current is generated. In addition, when the real part ε ′ of the complex relative permittivity is large, there is a characteristic that the electric force lines are easily captured, and coupled with the characteristic that it is easy to capture the magnetic field lines when the real part μ ′ of the complex relative permeability is large, Can be controlled.

  The antenna communication improving sheet 10 is provided with a conductor layer 12. The conductor layer 12 has an electric field shielding property of 20 dB or more, preferably 50 dB or more, against electromagnetic waves having a communication frequency. Further, the magnetic field shielding property is 10 dB or more, preferably 30 dB or more. Therefore, the conductor layer 12 can shield incoming electromagnetic waves, magnetic fields, and the like by attracting and reflecting magnetic flux due to the high magnetic permeability. The electric field shielding property or magnetic field shielding property can be measured by the KEC method or the Advantest method. The KEC method makes the numerical value unknown beyond the measurement limit of the measuring instrument, but the Advantest method does not have field shield measurement probes (antennas) compatible with 100 KHz to 1 MHz. In the present invention, the KEC method is used. In this case, for example, the electric field shielding property with respect to the 125 KHz band has reached the upper limit of measurement, and is set to 20 dB or more.

  From the above, the antenna communication improving sheet body 10 shields unwanted electromagnetic waves and noises such as magnetic fields coming from the conductor layer 12 side by the conductor layer 12 when wireless communication is performed using electromagnetic waves having a communication frequency. Furthermore, the magnetic field can be concentrated and passed by the shield layer 11 without losing the energy of the magnetic field formed by the electromagnetic wave having the communication frequency coming from the shield layer 11 side. Therefore, by using this antenna communication improving sheet 10, radio communication can be suitably performed using electromagnetic waves of the communication frequency while shielding noise.

  Electronic devices generate not only radio waves but also low-frequency magnetic field noise. It is difficult to shield such a low-frequency magnetic field only by a conductor layer such as a metal foil. In order to shield, a considerable thickness, for example, about 3 mm in the case of an aluminum foil is required. It is. A metal foil having such a thickness that can shield such a magnetic field is difficult to process, and when used to coat a tag (tag inlet), the tag (tag inlet) covered with the metal foil is , Flexibility and flexibility are greatly impaired.

  The shield layer 11 includes a magnetic material having a high electric resistance value. For example, a metal oxide such as ferrite or granular, rubber ferrite, a composite of a binder and flat soft magnetic powder, or the like is used. A composite of flat soft magnetic powder and a binder is preferable. A material containing the composite as a main constituent material and further containing a dielectric material, a dispersant and a flame retardant as required is used. The shield layer 11 of the present invention is mainly in the form of a sheet. Various organic polymer materials can be used as the binder, and examples thereof include polymer materials such as rubber, thermoplastic elastomer, and various plastics. For example, using a non-halogen polymer or a mixed material obtained by mixing a non-halogen polymer and another polymer as a binder, flat soft magnetic metal powder is filled, dispersed, or oriented at 20% by volume or more with respect to the binder. Can be obtained. In this embodiment, HNBR (hydrogenated nitrile butadiene rubber) and urethane resin are used, but the present invention is not limited to this. In addition, halogen-based polymers such as vinyl chloride resin and chlorinated polyethylene resin may be used. Mixtures of halogenated polymers and non-halogenated polymers can also be used. In addition to the organic polymer material, inorganic materials such as silicone rubber and silicone resin, and all materials having no conductivity such as wood, paper, gypsum, cement, and foam can be used. The material used to form these shield layers 11 is hereinafter referred to as “the present material”. The present material can obtain the above-mentioned preferable material constants μ ′, μ ″, ε ′, ε ″ with respect to electromagnetic waves having a communication frequency. Therefore, the shield layer 11 can concentrate and pass the magnetic field without losing the energy of the magnetic field formed by the electromagnetic wave having the communication frequency.

  The shield layer 11 has high flexibility and flexibility, and has an effect of shielding a low-frequency magnetic field because the soft magnetic metal powder is filled, dispersed, and oriented by 20% by volume or more with respect to the binder. Therefore, since the antenna communication improving sheet body 10 is provided not only with the conductor layer 12 but also with the shield layer 11, it has high flexibility and flexibility and can shield a low-frequency magnetic field. Therefore, since the antenna communication improving sheet body 10 is provided not only with the conductor layer 12 but also with the shield layer 11, it has high flexibility and flexibility and can shield a low-frequency magnetic field.

  The thickness dimension T1 of the shield layer 11 is 1 μm or more and 10 mm or less. By doing so, wireless communication can be suitably performed using electromagnetic waves having a communication frequency coming from the shield layer 11 side. Moreover, a low frequency magnetic field can be shielded.

  The conductor layer 12 is a layer containing a magnetic metal made of, for example, one or more metals or alloys selected from iron, cobalt, and nickel. By doing so, the magnetic shielding property of the conductor layer 12 can be enhanced, and the shielding property of noise coming from the conductor layer 12 side can be further enhanced. Furthermore, the conductor layer 12 can use a metal (aluminum, copper, etc.), a conductive member, a conductive treatment material, or the like. The conductor layer 12 has electromagnetic shielding properties, shifts the resonance frequency of the antenna coil of the tag (tag inlet) 15, and functions to hinder wireless communication when the shield layer 11 is not used. Thereby, the skimming prevention effect is obtained. When magnetic shielding is required, the conductor layer 12 is a magnetic metal layer, magnetic ceramic layer, Fe (iron) metal sheet, Co sheet, Ni sheet, stainless steel, or a composite of Fe metal powder and a binder. The body is used. The Fe metal sheet is exemplified by a metal foil of Fe or an Fe alloy. Examples of the Fe-based alloy include an Fe-based alloy having at least one element selected from Al, Mg, Co, Ni, Mo, B, Si, Sr, Nb, Cr, and the like. These may be in the form of a sheet, or may be plated, vapor-deposited or printed. In FIG. 3, a configuration in which the shield layer 11 is used only on one surface and an insulating layer having no magnetism is used on the other surface can be employed.

  Specific examples of the Fe-based metal sheet and Fe-based metal powder include SPCC [cold rolled sheet and steel strip (JIS G 3141 and JIS G 3313)], SPCD [cold rolled sheet steel and strip (JIS G 3141)]. , SUY (electromagnetic soft iron), amorphous metal foil, hot-dip galvanized steel sheet, and the like. Regardless of whether or not heat treatment is applied, it can be used if the initial permeability measured during use is 10 or more and less than 10,000. In a commercial item, a silver top (SF), Foil Top (made by Toyo Kohan Co., Ltd.) etc. can be used, for example.

  These Fe-based metal sheet and Fe-based metal powder preferably have an initial permeability of less than 10,000. In general, a material having an initial permeability of 10,000 or more is limited to permalloy, supermalloy, and the like, and has an initial permeability value that is reached when an appropriate heat treatment is performed. Although their magnetic permeability is high, they are unstable and their magnetic properties are greatly deteriorated in accordance with bending and stress application. That is, high permeability is achieved at the expense of workability and handling.

  On the other hand, the sheet body 10 for improving antenna communication according to the present invention is intended to emphasize workability rather than to ensure the desired magnetic shielding properties. That is, the performance is stable even if the secondary processing such as punching and bending the antenna communication improving sheet body 10 is performed. Furthermore, even if the after-curing step for increasing the magnetic permeability is omitted, a desired magnetic shielding property can be exhibited.

  Further, when the conductor layer 12 is composed of Fe or Fe-based alloy powder, the Fe or Fe-based alloy powder may be mixed with a binder and formed into a sheet shape. At this time, the Fe or Fe-based alloy powder is about 20 to 90% by volume, preferably 40 to 80% by volume, based on the total amount. For example, it is used in the properties of magnetic paint.

  The conductor layer 12 is not limited to a plate, foil, paint, or the like. For example, a material plated on a mesh, a woven fabric, a non-woven fabric, or the like may be used, or may be fixed by vapor deposition, plating, adsorption, or the like. Good.

  The magnetic field shielding effect is required to be 10 dB in the frequency range of 100 KHz to 1 GHz by a known method called the KEC method or the Advantest method. Preferably it is 30 dB or more. In this frequency region, the desired magnetic field shielding effect (10 dB) cannot be obtained with the single-layer configuration of the shield layer 11, and the conductor layer 12 is laminated.

  As the conductor layer 12, a nonmagnetic metal or a magnetic metal can be used. In particular, when a magnetic field shielding property of 30 dB or more is required at a low frequency (1 to 20 MHz), only a magnetic metal can be used. However, the antenna communication improving sheet body 10 of the present invention is not necessarily used by being laminated on the tag (tag inlet) 15 but also surrounds the RFID system including the reader and the tag (tag inlet) 15 (the voids are formed). It may be present). Considering the RFID system, it is possible to use the nonmagnetic conductor layer 12 and the conductor layer 12 made of magnetic metal for the surrounding shield plate for stacking the tag (tag inlet) 15.

  According to the present invention, when the conductor layer 12 is used as a support, a sheet having insulating properties, magnetic shielding properties, and noise suppression effects can be obtained by laminating the shield layer 11 in the coating process. The shield layer 11 also has an effect as a rust preventive agent for the conductor layer 12. The conductor layer 12 can be subjected to an adhesive treatment or an adhesion treatment as necessary.

  The thickness dimension T2 of the conductor layer 12 is not less than 0.1 μm and not more than 1 mm. By doing so, it is possible to shield noise coming from the conductor layer 12 side while ensuring sufficient flexibility and flexibility.

  The pressure-sensitive adhesive layer 13 is made of an adhesive material such as No. Teraoka Seisakusho. No. 707 and Nitto Denko Corporation No. Using 500. By providing this pressure-sensitive adhesive layer 13, pressure-sensitive adhesiveness is imparted to at least one surface portion of the sheet body 10. Such an adhesive layer 13 is laminated on one side in the thickness direction of the conductor layer 12.

  Further, the antenna communication improving sheet 10 has an overall thickness dimension T3 of 1.10 μm or more and 10 mm or less. By doing so, noise coming from the conductor layer 12 side can be shielded, and radio communication can be suitably performed using electromagnetic waves having a communication frequency coming from the shield layer 11 side. Furthermore, by using this thickness dimension T3, the antenna communication improving sheet 10 can sufficiently shield a low-frequency magnetic field.

  Further, the antenna communication improving sheet body 10 is formed with a small thickness C, and the shield layer 11 and the conductor layer 12 are made of the above-described materials, and have flexibility. Sufficient flexibility and flexibility are ensured. Therefore, the antenna communication improving sheet 10 can be freely deformed. Further, since the antenna communication improving sheet body 10 has flexibility, there are few restrictions on the installation place, and it can be used in a wide range of applications. For example, when it is used by being attached to an article, it can be provided following the shape of the article.

  Further, in the antenna communication improving sheet body 10, for example, a flame retardant or a flame retardant aid is added to the shield layer 11. By doing so, flame retardancy is imparted to the antenna communication improving sheet body 10. For example, an electronic device such as a mobile phone may be required to have flame retardancy for a polymer material or a sheet to be used.

  The flame retardant for obtaining such flame retardancy is not particularly limited, and examples thereof include phosphorus compounds, boron compounds, bromine flame retardants, zinc flame retardants, nitrogen flame retardants, and hydroxides. A flame retardant, a metal compound flame retardant, or 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 the present embodiment, a flame retardant chemical in which decabromodiphenyl oxide and antimony trioxide are mixed, for example, a trade name “Polysafe FCT-5” sold by Ajinomoto Fine Technology Co., Ltd. is applied to the binder (polymer material) 100. Evaluation equivalent to UL94V0 was achieved by adding 25 (weight ratio) of flame retardant chemicals.

  The antenna communication improving sheet 10 can be suitably used as a material constituting such an article or by being attached to the article. For example, it can be suitably used by attaching it to an article used in a space where it is desired to prevent combustion and generation of gas (smoke) accompanying it, such as an apparatus in an aircraft, a ship and a vehicle.

  Since the antenna communication improving sheet 10 is provided with adhesiveness or adhesiveness on at least one surface portion, when used by being attached to an article, the adhesiveness or adhesiveness is used to adhere or adhere to the article. Can be installed. Thereby, the antenna communication improving sheet 10 can be easily attached to the article. Therefore, the work for using the antenna communication improving sheet 10 and the electronic component including the same can be facilitated.

  FIG. 2 is a cross-sectional view showing the tag (tag inlet) 15 in a simplified manner. A tag (tag inlet) 15 which is an electronic component includes an antenna element 16 for transmitting and receiving electromagnetic wave signals (sometimes referred to as “electromagnetic wave signals”), and an integrated circuit (IC) electrically connected to the antenna element 16. The antenna communication improvement sheet 10 is further provided on the tag (tag inlet). The tag (tag inlet) 15 is an electronic device that transmits and receives signals using the antenna element 16.

  The antenna element 16 serving as an antenna means is an antenna coil formed in a coil 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 17 causes the control unit to store main information in the storage unit based on the storage command information.

  The antenna element 16 receives an electromagnetic wave signal representing information (hereinafter referred to as “transmission command information”) for instructing to transmit information stored in the storage unit (hereinafter referred to as “storage information”) from the information management device. Then, an electric signal representing transmission command information is given from the antenna element 16 to the IC 17. In the IC 17, the control unit reads information (stored information) stored in the storage unit based on the transmission command information, and gives an electrical signal representing the stored information to the antenna element 16. As a result, an electromagnetic wave signal representing stored information is transmitted from the antenna element 16.

  As described above, the tag (tag inlet) 15 is an electronic component that transmits and receives an electromagnetic wave signal using the antenna element 16. The tag (tag inlet) 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 antenna communication improving sheet body 10 is used so that such a tag (tag inlet) 15 can be used in the vicinity of the metal member 19. The antenna communication improving sheet 10 is provided on the opposite side of the antenna element 16 from the transmission / reception direction A antenna communication improvement, that is, on the other side with respect to the virtual plane 18. The antenna communication improving sheet 10 is provided with the conductor layer 12 and the pressure-sensitive adhesive layer 13 disposed on the opposite side of the antenna element 16 and the IC 17 from the shield layer 11.

  In FIG. 2, the antenna element 16 and the IC 17 are packaged by being mounted on a flexible tape, and the antenna communication improving sheet 10 is attached to the antenna element 16 and the IC 17. Are stacked in a state where When the antenna communication improving sheet 10 is attached to a package on which the antenna element 16 and the IC 17 are mounted, the antenna element 16 and the IC 17 are attached using, for example, an adhesive. Although the tag (tag inlet) 15 and the antenna communication improving sheet body 10 may be independent, they may be integrated, for example, may be configured to be integrally molded.

  A tag (tag inlet) 15 including the antenna communication improving sheet body 10 is used by being mounted on, for example, a metal member 19. This tag (tag inlet) 15 has an antenna communication improving sheet 10 disposed closer to the metal member 19 than the antenna element 16, and is used for improving antenna communication between the antenna element 16 and the metal member 19. The sheet body 10 is provided to be interposed. The pressure-sensitive adhesive layer 13 of the antenna communication improving sheet 10 faces the metal member 19, and the pressure-sensitive adhesive layer 13 is attached and attached to the metal member 19. The antenna communication improving sheet 10 is provided such that the shield layer 11 is disposed on the antenna element 16 side and the conductor layer 12 is disposed on the metal member 19 side.

  The antenna communication improving sheet 10 causes the electromagnetic wave arriving from the transmission / reception direction A to be concentrated and passed by the shield layer 11, and the electromagnetic field of one region of the two regions partitioned by the shield layer 11 is the other region. It is possible to prevent the electromagnetic field energy in one region from being transmitted to the other region. The electromagnetic field that can be shielded includes, of course, an electromagnetic field formed by electromagnetic waves, and therefore, the electromagnetic waves that form the electromagnetic fields can be shielded.

  Specifically, since the shield layer 11 is made of a material having a large real part μ ′ of complex relative permeability, when the shield layer 11 is provided in a magnetic field, for example, the signal is transmitted from the antenna element 16 in FIG. As shown in the example of the magnetic field due to electromagnetic waves, the magnetic lines of force 20 concentrate and pass through the shield layer 11, and do not pass through the conductor layer 12 stacked on the shield layer 11, or become difficult to pass. As a result, even if the conductor layer 12 is laminated on the shield layer 11, the magnetic field concentrates and passes through the shield layer 11, and the magnetic field in the region where the antenna element 16, which is one region partitioned by the shield layer 11, is provided. Further, it is possible to prevent leakage to the region where the conductor layer 12 which is the other region is provided.

  When the antenna element 16 is provided at a position similar to the position shown in FIG. 2, if the shield layer 11 is not provided, the magnetic field lines of the magnetic field due to the communication electromagnetic wave to be transmitted are represented by, for example, virtual lines 21 in FIG. 2. As shown, it approaches the conductor layer 12 and actually passes through the vicinity. When the lines of magnetic force approach the conductor layer 12 as described above, an eddy current is generated on the surface of the conductor layer 12 by being induced by the magnetic field. In the process of generating the eddy current, energy is lost (eddy current loss), and the magnetic field generated by the eddy current functions as a demagnetizing field to cancel (cancel) the magnetic field for communication. Thus, the energy of the magnetic field for communication is attenuated. On the other hand, by concentrating and passing the magnetic field through the shield layer 11 having a large electric resistance, the energy of the magnetic field on the side opposite to the conductor layer 12 with respect to the shield layer 11 is prevented from being reduced by the conductor layer 12. . Further, the shield layer 11 has a function of adjusting the resonance frequency of the antenna element 16 by its complex relative permeability and thickness. In addition, the energy of the magnetic field formed by the electromagnetic wave transmitted and received by the antenna element 16 on the antenna element 16 side opposite to the metal member 19 with respect to the antenna communication improving sheet 10 is caused by the metal member 19. , Prevent it from decreasing.

  According to the present invention, the shield layer 11 is made of a material in which a flat soft magnetic metal powder is mixed with a binder, and the soft magnetic metal powder is contained in an amount of 20% by volume or more with respect to the binder, and is oriented. Distributed by state. By aligning the flat soft magnetic metal powder in the sheet surface direction in a non-contact manner, the electromagnetic shielding property in the direction of penetrating the sheet surface of the sheet-like magnetic layer is high, and in the direction along the surface in the sheet surface The magnetic field component can flow with little resistance. As a result, the magnetic field can go around the coil of the antenna coil. Further, when the conductor layer 12 is present, the magnetic field flows along the conductor layer 12 near the surface of the conductor layer 12. Therefore, by arranging the shield layer 11 here, the magnetic field wraps around more reliably. Can be achieved. Such a dispersion state of the shield layer 11 and the electromagnetic shielding effect of the conductor layer 12 are synergistically excellent in shielding performance of unnecessary electromagnetic waves, and further, without losing energy of magnetic fields formed by electromagnetic waves of communication frequencies. The antenna communication improvement sheet | seat body 10 which achieves the outstanding effect that it can make it concentrate and pass can be implement | achieved.

  Furthermore, since the shield layer 11 is made of a material having a small imaginary part μ ″ of the complex relative permeability, even if a 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, the attenuation of the magnetic field energy by the conductor layer 12 and the metal member 19 can be prevented, the loss due to self can be suppressed small, and the attenuation of the magnetic field energy can be made as small as possible.

  By interposing such an antenna communication improving 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 increased. Attenuation by the conductor layer 12 and the metal member 19 is prevented. Moreover, the antenna communication improving sheet 10 itself for preventing the influence of the conductor layer 12 and the metal member 19 has a large electric resistance and a small magnetic loss. Therefore, the antenna element 16 can transmit and receive a long distance suitably. Therefore, even when the tag (tag inlet) 15 is provided in the vicinity of the metal member 19, information can be wirelessly communicated between the information management device and the tag (tag inlet) 15. Information represented by the electromagnetic wave signal transmitted from the management device can be stored in the tag (tag inlet) 15 and the information stored in the tag (tag inlet) 15 can be read out by the information management device.

  In this way, by using the antenna communication improving sheet 10, the electronic component using the antenna element 16 is provided in the vicinity of the metal member 19, for example, by being attached to the metal member 19, and the electromagnetic wave signal. The electronic component can be used in a state in which the preferred transmission / reception can be realized. Further, the antenna communication improving sheet body 10 can shield noise such as unnecessary electromagnetic waves and magnetic fields coming from the conductor layer 12 side by the conductor layer 12.

  Further, when the tag (tag inlet) 15 is used by being attached to an article, the antenna communication improving sheet 10 is arranged so that the antenna communication improving sheet 10 is disposed between the antenna element 16 and the article. Since the antenna element 16 can be laminated in advance, the resonance frequency of the antenna element 16 can be set in advance. Therefore, a wireless communication environment can be suitably realized regardless of the material of the surface of the article to which the tag (tag inlet) 15 is attached.

  Therefore, regardless of the material of the surface of the article to which the tag (tag inlet) 15 is attached, a wireless communication environment can be suitably realized, and the tag (tag inlet) 15 is attached to an article having a low shielding property against noise. Even in the case of pasting, noise such as unwanted electromagnetic waves and magnetic fields coming from the conductor layer 12 side can be shielded.

  The first embodiment is merely an example of the present invention, and the configuration can be changed. For example, the stacked configuration may be changed.

  FIG. 3 is a cross-sectional view schematically showing the antenna communication improving sheet 10 according to the second embodiment of the present invention. Parts corresponding to those of the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted to avoid duplication.

  The antenna communication improving sheet 10 is the same as that of the first embodiment except that the shield layer 11 is further laminated between the conductor layer 12 and the adhesive layer 13.

  Since the antenna communication improving sheet 10 is laminated so that the conductor layer 12 is sandwiched between the shield layers 11, if different tags (tag inlets) 15 are provided with the antenna communication improving sheet 10 interposed therebetween, The shield layer 11 is disposed between the tag (tag inlet) 15 and the conductor layer 12. Therefore, by providing different tags (tag inlets) 15 with the antenna communication improving sheet member 10 interposed therebetween, communication between the tags (tag inlets) 15 and the reader is possible.

  The antenna communication improving sheet 10 has a configuration in which a second pressure-sensitive adhesive layer 30 is provided on the side opposite to the conductor layer 12 with respect to the shield layer 11 as indicated by phantom lines in FIGS. 1 and 3. Also good. When such an antenna communication improving sheet 10 is used for a tag (tag inlet) 15, the antenna communication improving sheet 10 is attached to a package on which the antenna element 16 and the IC 17 are mounted, and the tag ( When the (tag inlet) 15 is configured, the second adhesive material layer 30 can be attached without using an additional adhesive, and the work is facilitated. Thus, the installation and mounting work of the sheet body 10 can be facilitated such that the antenna communication improving sheet body 10 can be easily incorporated into an electronic component.

  Further, the adhesive layer 13 may be used for attaching the antenna communication improving sheet body 10 to a package in which the antenna element 16 and the IC 17 are mounted when the adhesive layer 13 is incorporated in a tag (tag inlet) 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 adhesiveness to the shield layer 11 and does not form the adhesive layers 13 and 30 and provides adhesiveness to the surface may be sufficient. Furthermore, the structure which does not use the adhesive layers 13 and 30 is also possible. The pressure-sensitive adhesive layers 13 and 30 may exhibit adhesiveness when heated, and may behave as a dielectric layer near room temperature.

  In addition, the antenna communication improving sheet 10 may have irregularities formed on a part of the surface of the shield layer 11. By doing so, the fluctuation | variation of the relative magnetic permeability of the shield layer 11 can be absorbed, and it leads to stabilization of performance.

  Further, the use of the antenna communication improving sheet 10 is not limited to electronic parts, and can be widely used in applications that require at least shielding of a magnetic field. Of course, the electronic component is not limited to the tag (tag inlet) 15. For example, it can be used in a reading device.

  The reading device emits electromagnetic waves having a communication frequency from an antenna coil, which is an antenna means, toward the tag, and performs communication between the reading device and a tag (tag inlet) using the electromagnetic waves. When electromagnetic waves are radiated from the antenna coil, they are radiated not only in one direction of the magnetic core direction but also in the other direction of the magnetic core direction. Therefore, when electromagnetic waves are radiated from the antenna coil of the reader toward the tag (tag inlet), the electromagnetic waves are radiated in the direction opposite to the communication direction toward the tag (tag inlet) and also in the surroundings. When the electromagnetic wave in the direction opposite to the communication direction is attenuated, the electromagnetic wave in the communication direction is also affected, and there is a problem that a communication environment with the tag (tag inlet) cannot be secured. There is also a problem that RFID wireless communication between adjacent readers becomes difficult due to the influence of electromagnetic waves radiated around.

  For the above problem, the antenna communication improving sheet 10 having a cross-sectional area in the coil of the antenna coil and an area covering the coil is appropriately disposed on the side opposite to the communication direction of the antenna coil of the reading device. By providing a gap, the electromagnetic wave in the direction opposite to the communication direction can be shielded by the conductor layer 12, and further, the magnetic field formed by the electromagnetic wave can be concentrated and passed through the shield layer 11. Since electromagnetic waves in the communication direction are not attenuated, a communication environment with the tag (tag inlet) can be ensured. In this case, it can be used even in a close contact state without a gap.

  Further, when the reading device is used in the vicinity of an electronic device other than the reading device, the antenna communication improving sheet member 10 is previously set so that the antenna communication improving sheet member 10 is disposed between the antenna coil and the electronic device. Since the antenna coil can be laminated, the resonance frequency of the antenna coil can be set in advance. Therefore, a wireless communication environment can be suitably realized regardless of the presence of other electronic devices.

  For the later problem, the antenna communication improving sheet body 10 of the present invention may be used on the entire surface (including the upper and lower sides) of the reading apparatus or on the entire surface so as not to be affected by other wave interference. Is possible. In that case, the antenna communication improving sheet body 10 is positioned with a certain distance so as not to hinder RFID wireless communication in the reading device partially or entirely surrounded by the antenna communication improving sheet body 10. Thereby, reflection of electromagnetic waves is suppressed as much as possible, and wireless communication in a state free from other-wave interference becomes possible. In this case, if the configuration of the antenna communication improving sheet body 10 is configured such that the shield layer 11 is provided on both sides of the conductor layer 12, a suitable communication environment is not affected by adjacent readers even in adjacent readers. Can be obtained.

Below, the Example using the sheet | seat body 10 for antenna communication improvement of 1st Embodiment is shown.
Example 1
・ Shield layer 11
The shield layer 11 is coated using a material in which 40% by volume of flat Fe—Ni—Cr—Si alloy powder (JEM powder manufactured by Mitsubishi Materials) is filled in urethane resin (Nipporan manufactured by Nippon Polyurethane Industry) as the present material. Thereafter, the sheet is formed to a thickness of 100 μm by continuously applying pressure. The shield layer 11 is formed in a roll shape.
-Conductor layer 12
The conductor layer 12 is a 50 μm thick iron foil (FoilTop, manufactured by Toyo Kohan Co., Ltd.).

  By laminating the shield layer 11 on the conductor layer 12 coated with an adhesive, the antenna communication improving sheet body 10 of Example 1 was obtained. As the adhesive, XN-507 (crosslinking agent added type) manufactured by Yushi Co., Ltd. was used. The thickness of the antenna communication improving sheet 10 was 200 μm.

(Example 2)
After coating, the shield layer 11 is a material in which 40% by volume of flat Fe—Ni—Cr—Si alloy powder (JEM powder manufactured by Mitsubishi Materials) is filled in HNBR (Zeon pole manufactured by Nippon Zeon) as the present material. The same as in Example 1 except that the sheet was formed to a thickness of 150 μm by crosslinking by a pressure press method. The thickness of the antenna communication improving sheet 10 was 235 μm.

(Example 3)
The shield layer 11 is a sheet formed by hot pressing using a material in which 43% by volume of flat Fe—Ni—Cr—Si alloy powder (JEM powder manufactured by Mitsubishi Materials) is filled in urethane resin as the present material. Except that, it is the same as the first embodiment. The thickness of the antenna communication improving sheet 10 was 340 μm.

  In the above Examples 1 to 3, a tag (tag inlet) 61 is laminated on the shield layer 11 and a Cu plate is disposed in the immediate vicinity of the conductor layer 12 to create a state in which there is a metal in the vicinity as a communication disturbing member. The resonance frequency, the communication characteristics (the real part of the impedance at resonance), and the communication distance with the reader / writer were measured. In addition, the comparative example 1 is a result when not using the sheet | seat body 10 for antenna communication improvement of this invention in this structure.

  In Examples 4 to 6, as shown in Table 1, using the same shield layer 11 and conductor layer 12 as in Examples 1 to 3, the antenna communication improving sheet body 10 of the second embodiment referred to in the present invention is created. is doing. In this case, a tag (tag inlet) 61 is laminated on the shield layer, and a tag (tag inlet) that communicates with the tag (tag inlet) 61 at the same frequency as that of the tag (tag inlet) 61 is disposed in the immediate vicinity of the conductor layer 12. The structure which has an antenna coil in the vicinity as a communication interference member is created.

  Evaluation has performed the same item as Examples 1-3. Moreover, the comparative example 2 is a result when not using the sheet | seat body 10 for antenna communication improvement of this invention in this structure. In the embodiment, the shield layer 11 is provided with a resin coating layer. Since these have a dielectric constant, the resonance frequency may be shifted, and adjustment for this may be necessary, but they basically do not function as a communication disturbing member.

  About the sheet | seat body 10 for antenna communication improvement of Examples 1-6, it measured about the electric field shielding property, magnetic field shielding property, and communication distance of this material.

FIG. 4 is a graph showing the measurement results of the shield layer 11 of Example 3. As shown in FIG. 4, in the shield layer 11 of Example 1, the real part μ ′ of the complex relative permeability at the communication frequency is 30 or more, and the imaginary part μ ″ of the complex relative permeability is the complex relative permeability. The permeability loss term tan δ _μ (= μ ″ / μ ′), which is a value divided by the real part μ ′, is 0.2 or less.

  The present invention realizes the performance that the real part μ ′ of the complex relative permeability is high but the imaginary part μ ″ is low at a specific communication frequency (13.56 MHz). The communication frequency is 13.56 MHz. However, it is possible to obtain preferable specific material constants μ ′, μ ″, ε ′, ε ″ even when the communication frequency is 100 kHz or more and 30 GHz or less.

(Electric field shielding, magnetic field shielding)
The electric field shielding property at a frequency of 100 KHz to 1 GHz was measured by the KEC method. The sheet body 10 for improving antenna communication according to Example 3 was measured.

  FIG. 5 is a graph showing the results of the electric field shielding property of Example 3. As can be seen from FIG. 5, at a frequency of 100 KHz to 30 MHz, an electric field shielding property exceeding the measurement limit was exhibited, and an electric field shielding property of at least 20 dB or more was exhibited. Moreover, the electric field shielding property of 55 dB or more was shown at a frequency of 30 MHz to 1 GHz. The antenna communication improving sheet body 10 had an electric field shielding property against electromagnetic waves having a communication frequency of 20 dB or more. From this, in the present invention, a sheet body having a sufficiently high electric field shielding property was obtained.

  The magnetic (magnetic field) shielding property at a frequency of 100 KHz to 1 GHz was measured by the Advantest method. The antenna communication improving sheet body 10 of Example 3 was measured.

  FIG. 6 is a graph showing the results of magnetic field shielding properties. The point (□) shows the result of the magnetic field shielding property of Example 1, and the result of the magnetic field shielding property of Example 2 of the point (■).

  As can be seen from FIG. 6, it was confirmed that there was a shielding property of 10 dB or more at a frequency near 100 KHz and 60 dB or more at a frequency of 1 to 20 MHz, and electromagnetic wave interference (other wave interference) could be sufficiently prevented. The antenna communication improving sheet body 10 has a magnetic field shielding property against electromagnetic waves having a communication frequency of 10 dB or more. From this, in the present invention, a sheet body having a sufficiently high magnetic shielding property was obtained.

  The KEC method is a sheet evaluation method using an electromagnetic shielding effect measuring device developed by KEC (Kansai Electronics Promotion Center). In the Advantest method, a shield material evaluation jig TR17301A is connected to a spectrum analyzer, and the magnetic field shielding property can be evaluated using a loop antenna. Both are known shield characteristic measuring methods.

(Communication distance)
The tag (tag inlet) 61 is an Omron tag inlet V720S-D13P30, and the reader 62 is an OMRON reader / writer V720S-BC5D4. The communication distance of was measured.

  FIG. 7 is a schematic diagram showing a method for measuring a communication distance by the RFID system OMRON reader 62 and a tag (tag inlet) 61. As shown in FIG. 7, the measurement method is such that the antenna communication improving sheet 10 is arranged on the tag 61 via the base 63, and further the metal (Cu) 64 is arranged. In this state, the tag (tag inlet) A communication distance L between 61 and the reader 62 was measured.

  The communication distance in the free space of the tag (tag inlet) 61 used in the present invention was 290 mm, but when the metal (Cu) is in the vicinity, the communication distance becomes 0 mm and the tag (tag inlet) 61 Communication with the reader 62 could not be made.

  On the other hand, when the antenna communication improving sheet body 10 (Examples 1 to 3) is arranged, although the metal (Cu) is in the vicinity, the communication distance is shorter than in the case of free space, Communication between the tag (tag inlet) 61 and the reader 62 was possible. In this case, the resonance frequency can be lowered to a communicable band (10 to 16 MHz) by using the antenna communication improving sheet body 10 as compared with the real part of the resonance frequency and impedance when the metal (Cu) is in the vicinity. In addition, the real part of the impedance can be made larger. As a result, communication improvement was achieved.

  When antenna coils (tags using the same) having the same communication frequency band are used in an overlapping manner, a phenomenon that the resonance frequency is divided into a high frequency and a low frequency (referred to as bimodality) occurs. At this time, since the communication characteristics at the position of the important communication frequency deteriorate, there is a demand for communication improvement in this case. This is a case where the communication disturbing member is another antenna coil (a tag in the same communication frequency band), and is shown as a duplicate antenna coil in Table 1. FIG. 8 is a schematic diagram illustrating a method of measuring a communication distance when the communication disturbing member is an overlapping antenna coil.

  In this case, in order to make the tags (tag inlets) 61 on both sides of the antenna communication improving sheet body 10 communicable, the second embodiment referred to in the present invention is employed. When the antenna communication improving sheet 10 is used, the bimodality is lost, the resonance frequency can be brought to the communication frequency range, the real part of the impedance can be increased, and the communication distance is restored.

(Surface resistivity)
In order to evaluate the conductivity, the surface resistivity (based on JIS K6911) was measured. As a measuring device, it can measure with a well-known resistance meter etc., and used Hiresta MCP-HT450 made from Mitsubishi Chemical. Measurement results of examples, ⁷ Ω / □ Example 1 and 4 4 × 10, ⁶ Ω / □ Example 2 and 5 2 × 10, Examples 3, 6 is ⁶ × 10 6 Ω / □ met It was. Thus, by increasing the value of the surface resistivity to 1 × 10 ⁴ Ω / □ or more, no eddy current was generated in the shield layer 11.

  In the present invention, the antenna communication improving sheet 10 having improved electromagnetic shielding properties, particularly shielding properties against low-frequency noise and magnetic shielding, and electronic devices such as non-contact IC cards, IC tags, readers, readers / writers using the same. Has proposed. For this purpose, the real part μ ′ of the magnetic permeability of the shield layer 11 is increased and the magnetic field shielding property of the conductor layer 12 is increased. In order to improve communication, it is necessary to optimize the permeability (high μ ′ and low μ ″), thickness, and shape of the shield layer 11.

(Mutual inductance measurement)
In a state where the tag (tag inlet) 61 and the antenna communication improvement sheet body 10 are laminated, the resonance frequency and mutual inductance (the real part (R) of impedance in the table) of the tag (tag inlet) 61 are loop antennas on the material analyzer E4991A. Was measured. The real part (R) of the impedance indicates the Q value of the coil. Measurement was performed for the case where the communication obstruction member as shown in FIG. 7 is a metal and the case where the communication obstruction member as shown in FIG. 8 is another tag (tag inlet) 61 (overlapping antenna coil). The results are shown in Table 1 and FIGS. Moreover, the case where the antenna communication improvement sheet | seat body 10 is not used was made into the comparative examples 1 and 2.

  FIG. 9 is a graph showing the evaluation results of the communication characteristics when the communication disturbing member is a metal. In this graph, the frequency characteristics of the real part of the impedances of Examples 1 to 3 and Comparative Example 1 are shown. FIG. 10 is a graph showing an evaluation result of communication characteristics when the communication disturbing member is an overlapping antenna coil. In this graph, the frequency characteristics of the real part of the impedances of Examples 4 to 6 and Comparative Example 2 are shown.

  As can be seen from these graphs, by arranging the antenna communication improving sheet 10 between the communication disturbing member and the tag (tag inlet) 61, the resonance frequency can be adjusted to the communication frequency range, and the real part of the impedance can be increased. As a result, the Q value of the coil is increased, and communication characteristics are improved.

  The embodiments of the present invention are as described above, but are not limited to the embodiments, and various materials, shapes, performances, and combinations thereof can be used. It is also possible to provide a coating layer, an adhesive layer, or other dielectric layer with these configurations. Although the effect is shown with respect to the non-contact IC card, basically the same phenomenon occurs in the communication means using the antenna coil, and the technique of the present invention can be used as the improvement means. As a communication means using an antenna coil, an IC tag, a reader / writer that performs electromagnetic induction, or the like can be used as an interference avoidance means.

It is sectional drawing which simplifies and shows the sheet | seat body 10 for antenna communication improvement which is the 1st Embodiment of this invention. It is sectional drawing which shows the tag (tag inlet) 15 simplified. It is sectional drawing which simplifies and shows the sheet | seat body 10 for antenna communication improvement which is the 2nd Embodiment of this invention. 6 is a graph showing measurement results of a shield layer 11 of Example 3. It is a graph which shows the result of electric field shielding property. It is a graph which shows the result of magnetic field shielding. It is the schematic which shows the measuring method of the communication distance by the RFID system made from OMRON. It is the schematic which shows the measuring method of communication distance in case a communication disturbance member is an overlapping antenna coil. It is a graph which shows the evaluation result of the communication characteristic in case a communication obstruction member is a metal. It is a graph which shows the evaluation result of the communication characteristic in case a communication disturbance member is an overlapping antenna coil. It is the schematic which shows the structure of a general purpose tag inlet.

Explanation of symbols

10 Antenna Communication Improvement Sheet 11 Shield Layer 12 Conductor Layer 13 Adhesive Layer 15 Tag (Tag Inlet)
16 Antenna element 17 IC
18 Virtual surface 19 Communication interference member 20 Magnetic field line 21 Virtual line

Claims (11)

The value tan δ _μ obtained by dividing the real part μ ′ of the complex relative permeability by 30 or more and the imaginary part μ ″ of the complex relative permeability by the real part μ ′ of the complex relative permeability μ with respect to the electromagnetic wave of the communication frequency is , 0.2 or less, and a surface resistivity of 10 ⁴ Ω / □ or more is composed of a shield layer and a conductor layer,
An antenna communication improving sheet having an electric field shielding property of 20 dB or more and a magnetic field shielding property of 10 dB or more against electromagnetic waves of the communication frequency.   The sheet for improving antenna communication according to claim 1, wherein the sheet is laminated with a shield layer / conductor layer or laminated with a shield layer / conductor layer / shield layer.   The sheet for improving antenna communication according to claim 1 or 2, wherein the communication frequency is 100 kHz or more and 30 GHz or less.   The sheet for improving antenna communication according to any one of claims 1 to 3, wherein the conductor layer has a magnetic field shielding property of 30 dB or more with respect to electromagnetic waves having the communication frequency. The shield layer is made of a material mixed with flat soft magnetic metal powder in a binder,
The antenna communication according to any one of claims 1 to 4, wherein the soft magnetic metal powder is contained in an amount of 20% by volume or more with respect to the binder, and is dispersed in an oriented state. Sheet body for improvement.   The antenna conductor improving sheet body according to claim 1, wherein the conductor layer includes a magnetic metal.   The sheet for improving antenna communication according to claim 6, wherein the magnetic metal is made of one or more metals or alloys selected from iron, cobalt, and nickel.   8. The sheet for improving antenna communication according to claim 1, wherein the thickness is 1.0 μm or more and 10 mm or less.   The sheet for improving antenna communication according to any one of claims 1 to 8, wherein flame retardancy is imparted. Antenna means for transmitting and receiving electromagnetic wave signals;
An electronic apparatus comprising the antenna communication improving sheet according to claim 1, wherein the antenna means is laminated on a side opposite to a transmission / reception direction.   The electronic device according to claim 10, wherein the antenna communication improving sheet is disposed so as to cover the antenna unit while ensuring communication by the antenna unit.

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