JP4927625B2 - Magnetic shield sheet, non-contact IC card communication improving method, and non-contact IC card container - Google Patents

Description

  The present invention relates to a magnetic shield sheet, a non-contact IC card communication improvement method, and a non-contact IC card housing container that improve the RFID communication characteristics by allowing a magnetic field to concentrate in the sheet surface direction.

  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 method in which communication is performed by coupling between coils, and the frequency is a 125 kHz band, a band less than 135 kHz, an HF wave (13.56 MHz band, etc.), and 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. Among them, the application is developed mainly in the 13.56 MHz band. 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.

  The present invention is a magnetic shield sheet that improves communication characteristics when performing wireless RFID communication by so-called electromagnetic induction, which performs communication using an antenna coil. In principle, there is no effect in the radio wave communication, but the present invention is applied to the case where the electromagnetic induction method is used by using an antenna coil for near field communication even if the frequency is 800 MHz or higher. .

  FIG. 18 is a diagram showing a configuration of a non-contact IC card. The non-contact IC card has a configuration in which an antenna coil 1 for transmitting and receiving electromagnetic wave signals and an integrated circuit (IC) 2 for processing signals transmitted and received by the antenna coil are combined on a substrate 3. . A state in which the IC chip 2 and the antenna coil 1 are combined, or a package in which the IC chip 2 and the antenna coil 1 are combined is set as a card state. When the non-contact IC card receives the request signal from the reading device, it transmits the information stored in the IC, in other words, reads the information held in the non-contact IC card by the reading device. Configured to be able to. As a reverse information transmission, information can be written to a non-contact IC card. This non-contact IC card is built in, for example, a plastic card, and is used for transportation ticket gate systems, electronic payments, product (parts, intermediate products) management systems, entrance / exit management, and the like.

  When non-contact IC cards that perform electromagnetic induction communication approach each other, such as when a plurality of non-contact IC cards are accommodated in the same card case, the antenna coils exist in the vicinity, and the antenna coils Since the inductance changes and the resonance frequency of the antenna changes, each antenna coil becomes a communication obstruction member that obstructs wireless communication, and wireless communication with the reading device cannot be performed. By separating the antenna coils from each other, wireless communication between the non-contact IC card and the reading device can be enabled. However, a space for separating the antenna coils in a container that accommodates the non-contact IC card such as a card case. It is difficult to ensure.

  Further, since such a non-contact IC card can communicate without contacting a reading device, information held in the non-contact IC card can be read without the intention of the user. There is a possibility of skimming. In this skimming, a communication blocking member such as a magnetic material, a magnet, and a conductive member (for example, a metal plate) that affects electromagnetic waves of a communication frequency is disposed in the vicinity of an antenna coil included in a non-contact IC card. Can be prevented. Such a communication disturbing member is described in Patent Document 1, for example. Patent Document 1 describes a communication prevention device that blocks or attenuates the induction of electromagnetic waves between a reading device and a non-contact IC card and is arranged on one or both of the front and back surfaces of the non-contact IC card. . As the communication preventing device, electromagnetic shielding means, specifically, metal or the like is used. Skimming can be prevented by accommodating a non-contact IC card in a card case including the communication prevention device and arranging the non-contact IC card and the communication prevention device in the vicinity.

  However, if there is a communication prevention device in the vicinity of the antenna coil, such as housing a non-contact IC card in a card case equipped with the communication prevention device, skimming is prevented even if the user wants to communicate. Communication cannot be performed as it is, and it is necessary to separate the non-contact IC card from the communication prevention device, for example, taking out the non-contact IC card from the card case, which is very inconvenient.

  In Patent Document 2, when a card holder storing a plurality of non-contact type IC cards each having an antenna is placed or held over an antenna of a reader / writer, a conductor portion is provided on the card partition portion. By providing the first and second magnetic parts sandwiched therebetween, one non-contact type IC card that should originally read and write data and the card reader can be accurately electromagnetically coupled.

  Further, in Patent Document 3, in order to keep the use of the magnetic sheet to the minimum in the same usage situation as Patent Document 2, a space forming means is provided in addition to the conductive sheet and the magnetic sheet, and the shape of the space forming means A method for improving the communication performance is shown.

  When there is an antenna that interferes with communication as described above and a communication obstruction member such as a metal plate in the vicinity of the antenna coil, the magnetic field is concentrated without passing through without losing the energy of the magnetic field formed by electromagnetic waves of the communication frequency. By providing the magnetic shield sheet that can be made between the communication member having the antenna coil and the communication disturbing member, wireless communication between the communication member having the antenna coil and the reader can be made possible. Such a magnetic shield sheet is described in Patent Document 4, for example.

JP 2005-346549 A JP 2000-268146 A JP 2005-11044 A JP 2005-327939 A

  According to Patent Document 4, although such a magnetic shield sheet is very thin, even if a communication obstructing member is present in the vicinity, it is read with a communication member having an antenna coil by sticking it to the antenna coil. Since wireless communication with the apparatus can be enabled, it is very effective for reducing the size and thickness of electronic devices having a communication function using an antenna coil.

  The influence of a nearby conductor plate (for example, a metal plate) on an antenna coil in RFID communication is caused by the loss caused by eddy current generation (eddy current loss) on the surface of the conductor plate, and the magnetic field induced by the generated eddy current. Magnetic field loss (cancellation due to demagnetizing field) due to the opposite direction to the magnetic field for this, and the resonance frequency of the antenna coil changes, so that it differs from the communication frequency (for example, the resonance frequency of the communication radio wave from the reader side) That is.

  The magnetic shield sheet has a high electrical resistance value and does not generate eddy currents. The magnetic shield sheet has a high real part μ ′ of the complex relative permeability, has an effect of taking in a magnetic field (magnetic flux), and reduces the magnetic field (magnetic flux) reaching the communication disturbing member. The magnetic shield sheet has a low imaginary part μ ″ of the complex relative permeability, and allows the collected magnetic field (magnetic flux) to pass through in a state where energy loss is small. Therefore, the magnetic shield sheet has the above-described performance. Even if there is a nearby conductor plate, the RFID communication characteristics by the antenna coil can be improved.

However, when non-contact IC cards having communication frequencies in the same frequency band are overlapped, a phenomenon different from the case where a conductor plate exists near the antenna coil occurs. If this overlaps, the resonance frequency f0 that the non-contact card originally has is divided into two, f1 (<f0) and f2 (> f0), etc. This is a phenomenon in which the communication characteristics are extremely inferior. In this case, one of the frequencies of the non-contact type IC card which should originally read and write data is shifted low, so that in the case of the nearby conductor plate, the resonance frequency is always shifted to the higher side. It has become a phenomenon.
In such a case, improvement of RFID communication characteristics cannot be achieved by simply attaching a magnetic sheet to the antenna coil. When non-contact IC cards are overlapped, to improve communication, reduce the electromagnetic coupling of nearby antenna coils (add electromagnetic shielding) and adjust the resonance frequency for communication. Need to do one.

  The present invention can concentrate the magnetic field in the sheet surface direction without losing the energy of the magnetic field formed by the electromagnetic wave of the communication frequency, reduce the influence of the overlapping antenna coil, and originally communicate. Magnetic shield sheet and non-contact IC card capable of selectively or concurrently providing a skimming prevention function and a communication improvement function to a non-contact IC card by ensuring communication with a card reader (writer) to be performed A communication improvement method and a contactless IC card container are provided. As a communication improvement method, a frequency adjustment method using a magnetic shield sheet (conductor layer, magnetic layer) not described in Patent Document 3 is described.

The present invention is a magnetic shield sheet that is used when a non-contact IC card capable of non-contact communication with an external device overlaps to improve communication characteristics,
The magnetic material layer has a real part μ ′ of a complex relative permeability with respect to electromagnetic waves of a communication frequency and a magnetic material layer thickness t (μm).
μ ′ × t> 10,000
And
It is a magnetic shield sheet that is arranged between non-contact IC cards and improves communication characteristics by means of a resonance frequency adjusting means that at least a high frequency component of the resonance frequency matches or approaches the resonance frequency f0 that the non-contact IC card originally has. .
The present invention is also a magnetic shield sheet for improving communication characteristics when a non-contact IC card capable of non-contact communication with an external device is overlapped,
The magnetic material layer / conductor layer and the magnetic material layer / conductor layer / magnetic material layer, wherein the magnetic material layer has a real part μ ′ of complex relative permeability with respect to electromagnetic waves of communication frequency, and a magnetic material layer thickness t ( μm)
μ ′ × t> 2,000
And
It is a magnetic shield sheet that is arranged between non-contact IC cards and improves communication characteristics by means of a resonance frequency adjusting means that at least a high frequency component of the resonance frequency matches or approaches the resonance frequency f0 that the non-contact IC card originally has. .

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 with respect to the electromagnetic wave of the communication frequency. The measured value tan δμ is a magnetic shield sheet made of a magnetic layer having a surface resistivity of 10 ⁴ Ω / □ or more while being 0.2 or less .

  Further, the present invention is characterized in that the resonance frequency and the communication frequency are 100 kHz or more and 30 GHz or less.

Further, in the present invention, the magnetic layer is made of a material in which a flat soft magnetic metal powder is mixed with 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 has a magnetic shield property of 20 dB or more by the KEC method or the Advantest method with respect to the electromagnetic wave having the communication frequency.

  In the invention, it is preferable that the conductor layer is made of at least one selected from magnetic metal, amorphous metal, magnetic stainless steel, and ferrite.

Further, the present invention is characterized in that the thickness is 0.05 mm or more and 5 mm or less.
According to the present invention, the magnetic shield sheet according to any one of claims 1 to 9 is disposed between the non-contact IC cards, and the resonance frequency that the non-contact IC card originally has at least a high frequency component of the resonance frequency is provided. It is a non-contact IC card communication improvement method characterized in that communication characteristics are improved by matching or approaching f0.

  The present invention is also a non-contact IC card communication improving device and a non-contact IC card storage container made of a magnetic shield sheet.

  According to the present invention, when non-contact IC cards are overlapped, that is, when antenna coils communicating by electromagnetic induction are overlapped, particularly in the case of an antenna coil having a resonance frequency in the same frequency band, the non-contact card originally has. As the resonance frequency f0 is divided into two, f1 (<f0) and f2 (> f0), there is a phenomenon that communication in the vicinity of f0 with an external device is significantly impaired. This frequency shift showing bimodality occurs even if the non-contact IC cards overlap partially.

By arranging the magnetic shield sheet between the non-contact IC cards, the communication characteristics in the above case can be improved. Communication can be improved by a resonance frequency adjustment method in which at least f2 is brought close to f0 by the magnetic layer constituting the magnetic shield sheet, or the resonance frequency shifted to a frequency higher than f0 by the conductor layer is brought close to f0.
The magnetic shield sheet of the present invention comprises a magnetic layer, and the magnetic layer has a product of a real part μ ′ of complex relative permeability with respect to electromagnetic waves of communication frequency and a magnetic layer thickness t (μm) of 10, When it is larger than 000, it becomes possible to bring f2 close to f0 only by the magnetic layer. Further, the Q value can be increased. In this case, even if a magnetic shield sheet is used, the resonance frequency may be bimodal, but communication is possible.
The magnetic shield sheet of the present invention is configured to be a magnetic layer / conductor layer and a magnetic layer / conductor layer / magnetic layer, and the magnetic layer is a real part μ ′ of a complex relative permeability with respect to electromagnetic waves of communication frequency. When the product of the magnetic layer thickness t (μm) is larger than 2,000, communication is possible. In this case, the conductor layer can further shield the electromagnetic coupling between the non-contact IC cards (antenna coils), and shifts the antenna resonance frequency to a high frequency, so that the non-contact IC cards are overlapped. However, the resonance frequency can be unimodal. Here, the resonance frequency is lowered by the magnetic layer, so that it can be adjusted close to f0 and the real part (R) of the impedance can be increased, so that the Q value is increased and the non-contact IC located on the magnetic layer side. Card communication is possible.

  The mechanism for improving the communication of the non-contact IC card that is overlapped by the magnetic shield sheet of the present invention is as follows.

The first is to reduce the electromagnetic coupling between the overlapping antenna coils by arranging a magnetic layer and a conductor layer in between.
The second is to raise the resonance frequency of the antenna coil from f0 by the conductor layer.
Third, the antenna resonance frequency is lowered by the magnetic layer, and the frequency is adjusted to f0 or near f0.
The fourth is to increase the Q value by adjusting the real value (R) of the impedance high by the magnetic layer.

  As described above, even when a non-contact IC card capable of communicating at a frequency f0 in free space is present in the vicinity in a manner in which the non-contact IC cards are overlapped in a container such as a card holder, the RFID is used at a frequency near f0. Communication is possible. It is not necessary to satisfy all of the first to fourth mechanisms, and the mechanism may be selected so that the communication characteristics are optimized.

According to the present invention, the magnetic shield sheet is provided with a magnetic layer having high electrical resistance. In the magnetic layer, the larger the real part μ ′ of the complex relative permeability is, the more the magnetic lines of force (magnetic flux) pass. The smaller the real part μ ′ of the complex relative permeability is, the more the magnetic line of force (flux) passes. It becomes difficult structure. Further, the magnetic 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. Further, the surface resistivity of the magnetic layer has a high electric resistance value of 10 ⁴ Ω / □ or more, and the occurrence of eddy current in the magnetic layer itself is also suppressed.

  The magnetic layer has a real part μ ′ of complex relative permeability as large as 30 or more for electromagnetic waves of communication frequency, and the imaginary part μ ″ of complex relative permeability is divided by the real part μ ′ of complex relative permeability. The value tan δμ 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. As a result, it is possible to make it easier for magnetic lines of force (magnetic flux) to pass through the magnetic layer with respect to the magnetic field formed by electromagnetic waves of the communication frequency, and to prevent loss of magnetic field energy. Therefore, by using a magnetic shield sheet including such a magnetic layer, electromagnetic waves of communication frequency can be concentrated and passed in the surface of the magnetic layer so as not to leak while suppressing a loss of energy. . In addition, since no eddy current is generated in the magnetic layer itself and no demagnetizing field is generated from the eddy current, there is no loss due to the magnetic layer, and the magnetic field can pass. That is, it is possible to minimize the influence of the magnetic field on the conductor plate.

  Even when the antenna coil is present in the vicinity of the antenna coil, such a magnetic layer is provided between the antenna coil and the antenna coil so that radio communication is suitably performed using electromagnetic waves having a communication frequency. be able to.

  From the above, the magnetic shield sheet is a state in which there is a communication obstructing member in the vicinity of the antenna coil, such as housing a non-contact IC card in the same card case when performing wireless communication using electromagnetic waves of communication frequency. Even so, by providing between the antenna coil and the communication disturbing member, radio communication can be suitably performed using electromagnetic waves of the communication frequency.

  Moreover, the non-contact IC card existing in the vicinity of the magnetic seal sheet can control the communication direction. For example, communication of reading and writing of a non-contact IC card on both sides of the magnetic shield sheet is possible. The non-contact IC card adjacent to the conductor layer becomes unable to communicate by greatly shifting the resonance frequency, and has a skimming prevention function. By using the magnetic shield sheet in this way, communication between the non-contact IC card and the reader / writer and the skimming prevention function can be provided without separating the antenna coils of the two non-contact IC cards. It is.

  As described above, when the magnetic shield sheet is a laminate, the magnetic layer is provided on at least one outer layer, so that a conductor layer is provided on the opposite side while ensuring a suitable wireless communication environment. Therefore, skimming from the opposite side to the transmission / reception direction can be prevented.

  Moreover, the non-contact IC card existing in the vicinity of the magnetic shield sheet can control the communication direction. For example, when the magnetic layer and the conductor layer are laminated so as to be both outer layers, communication is not possible from the non-contact IC card on the conductor layer side, and communication is possible from the non-contact IC card on the magnetic layer side. In this case, the communication characteristics can be anisotropic, and the non-contact IC card on the conductor layer side has an effect of preventing skimming. Further, when magnetic layers are laminated on both sides of the conductor layer, the non-contact IC cards on both sides of the magnetic shield sheet can communicate for reading and writing. By using the magnetic shield sheet in this way, communication between the non-contact IC card and the reader can be performed without separating the antenna coils of the two non-contact IC cards.

  Further, according to the present invention, the resonance frequency and the communication frequency are 100 kHz or more and 30 GHz or less, and wireless communication can be suitably performed using electromagnetic waves of this communication frequency. For example, it can be used for wireless communication of an RFID tag or a non-contact IC card.

  According to the invention, the magnetic layer 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 based on the binder. Distributed by state. By orienting in the plane direction of the magnetic layer in such a manner that the flat soft magnetic metal powder is not in contact, the electromagnetic shielding property in the direction penetrating the sheet surface of the sheet-like magnetic layer is high, and the in-plane of the magnetic layer is In the direction along the 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. In addition, if there is a conductor layer, the magnetic field will flow along the conductor layer near the surface of the conductor layer, so by placing the magnetic layer here, the magnetic field wraparound can be achieved more reliably. Can do. Such a dispersed state of the magnetic layer realizes a magnetic shield sheet that achieves an excellent effect of allowing the magnetic field to be concentrated and passed without losing the energy of the magnetic field formed by the electromagnetic wave of the communication frequency. can do.

  According to the present invention, the conductor layer has a magnetic shielding property of 20 dB or more by the KEC method or the Advantest method with respect to electromagnetic waves having a communication frequency. By doing so, the electromagnetic coupling between non-contact IC cards can be more reliably shielded.

  According to the invention, the conductor layer is preferably made of one or more selected from magnetic metal, amorphous metal, magnetic stainless steel and ferrite. By doing so, the magnetic shielding property (magnetic field shielding property) of a conductor layer can be improved and the influence from other interference electromagnetic waves can be suppressed.

  Moreover, according to this invention, thickness is 0.05 mm or more and 5 mm or less. By doing so, a suitable wireless communication environment can be realized, and a thin and light magnetic shield card can be obtained.

  Further, according to the present invention, there is provided a non-conductive layered structure in which a magnetic layer and an antenna coil for transmitting / receiving an electromagnetic wave signal are stacked so that the magnetic layer is opposite to the transmitting / receiving direction of the antenna coil. A non-contact IC card comprising a covering layer that is made of a conductive material and at least partially covers the laminate.

  By doing so, the non-contact IC card can suitably perform wireless communication using an electromagnetic wave having a communication frequency coming from the magnetic layer side. Furthermore, in order to extend the communication distance on the magnetic layer side, the resonance frequency of the antenna coil laminated on the magnetic layer can be adjusted. As a method of adjustment, the C component may be applied in a circuit manner, or the complex relative permeability and thickness of the magnetic layer may be adjusted. Furthermore, this electronic device can be reduced in size by incorporating an antenna coil.

  According to the present invention, there is also provided a magnetic shield sheet comprising a magnetic layer and a conductor layer containing a metal, wherein a non-contact IC card for transmitting and receiving electromagnetic wave signals is laminated so as to be disposed on at least one outer layer. A non-contact IC card including the laminated body and a coating layer made of a non-conductive material and covering at least partially the laminated body.

  By doing so, the non-contact IC card can suitably perform wireless communication using an electromagnetic wave having a communication frequency coming from the magnetic layer side. Furthermore, in order to extend the communication distance on the magnetic layer side, it is possible to adjust the resonance frequency and the Q value of the non-contact IC card laminated on the magnetic layer. As a method of adjustment, the C component may be applied in a circuit manner, or the complex relative permeability and thickness of the magnetic layer may be adjusted. Furthermore, this non-contact IC card can be miniaturized by incorporating a magnetic shield sheet. Further, since the conductor layers are laminated, skimming can be prevented.

  According to the invention, the magnetic shield sheet having the above-described configuration is disposed between the non-contact IC cards.

  By doing so, at least the high frequency component of the resonance frequency can be matched or brought close to the resonance frequency f0 that the contactless IC card originally has, and the communication characteristics of the contactless IC card can be improved.

  Further, according to the present invention, there is provided a storage container including a storage unit that stores a non-contact IC card that transmits and receives electromagnetic wave signals having a communication frequency, and the storage unit includes the magnetic shield sheet. is there. By doing so, even if there is a communication obstruction member in the vicinity of the antenna coil, such as accommodating a plurality of non-contact IC cards, the antenna coil does not need to be separated from the communication obstruction member, and remains in the accommodated state. Can communicate. Further, skimming of the non-contact IC card can be prevented.

  FIG. 1 is a cross-sectional view showing a simplified magnetic shield sheet 10 according to the first embodiment of the present invention. The magnetic shield sheet 10 is a magnetic shield card 10 used to concentrate and pass at least a magnetic field. In this embodiment, for example, the magnetic shield sheet 10 is sandwiched between a non-contact IC card 15 and a non-contact IC card 15, It is used to enable wireless communication between each non-contact IC card 15 and the reader. 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 4.91 MHz band, a 125 kHz band, or a band less than 135 kHz. The numerical values of these frequencies are representative values, and the numerical values include a range used for communication.

  The magnetic shield sheet 10 includes a magnetic layer 11. The magnetic layer 11 is a layer for allowing at least a magnetic field to concentrate in the plane of the magnetic layer 11 and passing it. The magnetic layer 11 is configured with an area including the antenna coil 16 and the inside of the coil in order to suppress interference due to the coupling of the antenna coil 16 of the non-contact IC card 15 that is present overlapping. The magnetic layer 11 is used together with the coating layer 12. In this example, the coating layer 12 covers the entire surface. There may or may not be an adhesive layer, an adhesive layer or a dielectric layer between the magnetic layer 11 and the coating layer 12.

  The magnetic 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 magnetic layer 11 has a large real part μ ′ of the complex relative permeability. As the real part μ ′ of the complex relative permeability is smaller, the magnetic force line (magnetic flux) is less likely to pass through. The greater the imaginary part μ ″ of the magnetic susceptibility, the more the energy of the magnetic field is lost, and the smaller the imaginary part μ ″ of the complex relative permeability, the less likely the energy of the magnetic field is lost.

Specifically, the real part μ ′ of the complex relative permeability of the magnetic 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 δμ (= μ ″ / μ ′) is 0.2 or less, preferably 0.1 or less, and the imaginary number of the complex relative permeability compared with the real part μ ′ of the complex relative permeability. The part μ ”is small. The preferred range in which the permeability loss term tan δμ 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 tan δμ (= μ ″ / μ ′) is 0.2, the imaginary part μ ″ of the complex relative permeability is 12 and is larger than 6. In such a case, tan δμ ( = Μ ″ / μ ′) is preferentially applied in the range of 0.2 or less, and the preferable range of the imaginary part μ ″ of the complex relative permeability is 12 or less. With respect to the magnetic field, it is possible to make it easy for magnetic lines of force (magnetic flux) to pass through the magnetic layer 11 and not to lose the energy of the magnetic field on the magnetic layer 11. Therefore, by using the magnetic layer 11 Communication frequency power 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 magnetic layer 11 is preferably as large as possible. There is no upper limit for the real part μ ′. The smaller the imaginary part μ ″ of the complex relative permeability is, the better, and the lower limit is equal to no, but cannot be less than 0. Therefore, the permeability loss term tan δμ 0 is the lower limit. Furthermore, the surface resistivity of the magnetic layer 11 has a high electric resistance value of 10 ⁴ Ω / □ or more, and the occurrence of eddy currents in the magnetic layer 11 itself is also suppressed.

  The magnetic layer 11 of the present invention is made of 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. Preferably, a material containing a flat soft magnetic powder and a binder as main constituent materials and further containing a dielectric material, a dispersing agent and a flame retardant as required is used. The magnetic layer 11 of the present invention is a composite and is mainly in the form of a sheet.

  As the flat soft magnetic powder, for example, Sendust (Fe-Si-Al alloy), Permalloy (Fe-Ni alloy), Silicon copper (Fe-Cu-Si alloy), Fe-Si alloy, Fe-Si-B (- Cu-Nb) alloy, Fe-Ni-Cr-Si alloy, Fe-Si-Cr alloy, Fe-Si-Al-Ni-Cr alloy, Fe-Ni-Cr alloy, Fe-Cr-Al-Si alloy, etc. Can be mentioned. In addition to these, 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. Metals and alloys made of Ni, Co, etc. can also be used. Further, non-flat ferrite powder or pure iron particles may be used. Examples of ferrite powder include soft ferrite such as Mn—Zn ferrite, Ni—Zn ferrite, Mn—Mg ferrite, Mn ferrite, Cu—Zn ferrite, and Cu—Mg—Zn ferrite, and hard ferrite that is a permanent magnet material. Can be mentioned. Oxides can also be used. Examples of pure iron particles include carbonyl iron powder. It is preferable to use a flat soft magnetic powder having a high real part of complex relative permeability. In addition to using these magnetic materials alone, a plurality of them may be blended. As the soft magnetic powder, a combination of a flat soft magnetic powder and a non-flat soft magnetic powder (acicular, fibrous, spherical, massive, etc.) may be used, but at least one of the combinations should be flat. I need it. The particle diameter of the soft magnetic powder is 0.1 to 300 μm, preferably 20 to 100 μm. The aspect ratio of the flat soft magnetic powder is 2 to 500, preferably 10 to 100. The soft magnetic powder may have an oxide film on the surface in order to improve the corrosion resistance.

  The soft magnetic powder is preferably surface-treated. As the surface treatment, a general treatment with a coupling agent or a surfactant can be used. Of these, resin coating is preferable, and this improves the affinity between the flat soft magnetic powder and the binder, so that the flat soft magnetic powder can be filled with high density. As the resin for surface coating, organic polymer materials (rubbers, thermoplastic elastomers, various plastics) that are the same as the binder to be used or excellent in affinity with the binder to be used can be used. The coating amount of the resin is preferably about 0.01 to 10% by weight with respect to the content of the coated flat soft magnetic powder. Other surface treatment materials include silica and ZnO. By coating the soft magnetic powder with these, it is possible to increase the electrical resistance value of the composite.

  As the binder used in the magnetic layer 11 of the present invention, various organic polymer materials can be used, and examples thereof include polymer materials such as rubber, thermoplastic elastomer, and various plastics. Examples of the rubber include natural rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, ethylene-propylene rubber, EPDM rubber, butyl rubber, chloroprene rubber, nitrile rubber, acrylic rubber, epichlorohydrin rubber, fluorine rubber, Synthetic rubber such as urethane rubber, chlorinated polyethylene rubber, hydrogenated nitrile rubber (HNBR), ethylene-vinyl acetate copolymer, ethylene-acrylic rubber, ethylene-acrylic acid ester copolymer, ethylene copolymer, silicone rubber The thing which modified these rubber | gum by various modification | denaturation processes individually or is mentioned. In this embodiment, HNBR (hydrogenated nitrile butadiene rubber) is used, but the present invention is not limited to this.

  These rubbers can be used alone or in combination. In addition to vulcanizing agents, rubbers may be appropriately mixed with vulcanization accelerators, anti-aging agents, softeners, plasticizers, fillers, coloring agents, and the like that have been conventionally used as rubber compounding agents. it can. In addition to these, arbitrary additives can be used. For example, a predetermined amount of dielectric (carbon black, graphite, titanium oxide, etc.) for controlling the dielectric constant, and a heat conductive material (boron nitride, aluminum nitride, alumina, magnesium oxide, zinc oxide) for imparting heat dissipation characteristics Etc.) can be added by designing the material according to impedance matching to the unnecessary electromagnetic wave generated in the electronic device used and the temperature environment. In addition, select processing aids (such as lubricants), flame retardants (halogen flame retardants, phosphorus flame retardants, zinc flame retardants, nitrogen flame retardants, hydroxide flame retardants, antimony flame retardants) as appropriate. It may be added. Further, these heat conductive materials and flame retardants may be subjected to surface treatment.

  Examples of the elastomer include chlorinated compounds such as chlorinated polyethylene and polyvinyl chloride, various elastomers such as polystyrene, polyolefin, polyurethane, polyester, polyamide, fluorine, and silicone (including thermoplastic elastomers). ).

  Examples of the resin include polyester urethane resin (adipate, carbonate, caprolactam ester, etc.), polyether urethane resin, polyvinyl acetal resin, polyethylene, polypropylene, AS resin, ABS resin, polystyrene, polyvinyl chloride, Polyvinylidene chloride, polyvinyl acetate, ethylene-vinyl acetate copolymer, fluorine resin, acrylic resin, nylon, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polynaphthalene terephthalate, alkyd resin, unsaturated polyester, polysulfone, polyurethane resin ( All types other than those described above except polyester and polyether), phenol resin, urea resin, epoxy resin, silicone resin, melamine resin, acrylic Resins, acrylic copolymer, thermoplastic resins or thermosetting resins such as an alkyl acrylic. These elastomers or resins may be used alone, or may be used after modification (grafting, copolymerization, chemical treatment, etc.), or in a composite system (blend, polymer alloy, composite, etc.) It can also be used. It can also be blended in acrylic silicone, acrylic urethane, acrylic lacquer, various primers, fluorine paint, silicone paint, and UV paint. These elastomers and resins have a functional group (glycidyl group, carboxyl group, sulfonic acid group, maleic acid group, polar group such as amino group, etc.) to improve the cohesive force, for example, via a metal salt or quaternary amine. A polar group capable of forming an ionomer).

  In addition to the organic polymer material, any material having no electrical conductivity such as an inorganic material, wood, paper, gypsum, cement, and foam can be used.

  Preferred polymers include, but are not limited to, HNBR, chlorinated polyethylene, SBS (styrene-butadiene-styrene copolymer) and its hydrogenated product, silicone, and urethane resin.

  The magnetic layer 11 of the present invention is obtained by applying a magnetic paint containing a flat soft magnetic powder and a binder onto a support with a blade or the like, drying, and then separating (peeling) the support from the support. It is obtained by. If separation (peeling) from the support is not necessary, it may be omitted.

  For the preparation of the magnetic coating, a solvent for dissolving or dispersing the flat soft magnetic powder and the binder is used. Examples of such a solvent include, but are not limited to, ketones such as acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone, and cyclohexanone, alcohols such as methanol, ethanol, propanol, butanol, and isopropyl alcohol, Esters such as methyl acetate, ethyl acetate, propyl acetate, butyl acetate, ethyl lactate, and ethyl glycol acetate; ethers such as diethylene glycol dimethyl ether, 2-ethoxyethanol, tetrahydrofuran, and dioxane; aromatic hydrocarbons such as benzene, toluene, and xylene Compounds, halogenated hydrocarbon compounds such as methylene chloride, ethylene chloride, carbon tetrachloride, chloroform, chlorobenzene, and the like can be used. These solvents can be used alone or in combination of two or more.

  The magnetic paint contains the solvent in an amount of 1000 parts by weight or less, preferably 100 to 800 parts by weight, based on 100 parts by weight of the binder. On the other hand, if the solvent content exceeds 1000 parts by weight, residual air remains in the sheet, which is not preferable.

  As the dispersion and kneading apparatus for preparing the coating material, for example, a kneader, an agitator, a ball mill, a sound mill, a roll mill, an extruder, a homogenizer, an ultrasonic disperser, a biaxial planetary kneader, or the like can be used. Of these dispersing and mixing devices, an agitator, a ball mill, a roll mill, a homogenizer, an ultrasonic disperser, a two-axis planetary kneader, etc. that do not break or give distortion to the flat soft magnetic powder are particularly preferable.

  The support is not particularly limited. For example, paper, paper laminated with a polymer resin such as polyolefin, paper, release paper, polymer resin, cloth, nonwoven fabric, metal, metal treatment (evaporation, plating) ). Among these, a thin and strong polymer resin is preferable. Examples of the polymer resin include polyesters such as polyethylene terephthalate and polyethylene-2,6-naphthalate, polyolefins such as polyethylene and polypropylene, and these polyolefins. Fluorine resin in which part or all of hydrogen is replaced with fluorine resin, cellulose derivatives such as cellulose triacetate and cellulose diacetate, vinyl resins such as polyvinyl chloride, vinylidene resins such as polyvinylidene chloride, polycarbonate, polyphenylene sulfide, polyamide Examples include imide and polyimide. It is preferable that the surface of these polymer resins is subjected to a release treatment by a release treatment such as fluorine or silicone because the magnetic layer 11 can be easily removed. These polymer resins are preferably in the form of a film having a thickness of about 1 μm to 100 mm. However, when the support is used in a form that does not peel off, these mold release treatments are unnecessary, and the surface for the adhesion treatment or anchor coating is subjected to an unevenness imparting treatment.

  The method for applying the magnetic coating material on the support is not particularly limited. For example, air doctor coat, blade coat, wire bar coat, air knife coat, squeeze coat, impregnation coat, reverse roll coat, transfer roll coat Any of conventional methods such as gravure coating, kiss coating, cast coating, extrusion coating, die coating, and spin coating can be employed.

  Moreover, a crosslinking agent may be added to crosslink the binder to improve the heat resistance of the magnetic layer 11. For this cross-linking, not only a cross-linking agent and a cross-linking aid are blended, but also means such as UV curing, photo-curing and radiation curing can be selected.

  Although the magnetic shield sheet 10 has an arbitrary configuration, a coating layer 12 is provided. Since the covering layer 12 covers at least a part of the magnetic layer 11, it protects the magnetic layer 11 and increases the mechanical strength of the magnetic shield sheet 10, for example, when sandwiched between non-contact IC cards 15. Further, it is possible to suppress bending and damage to the magnetic layer 11. Therefore, since the magnetic shield sheet 10 has high mechanical strength, it is possible to prevent the preferred wireless communication environment from being damaged by the magnetic layer 11 being damaged or bent. Moreover, since the coating layer 12 is made of a non-conductive material, generation of eddy current in the coating layer 12 is prevented. Therefore, it is possible to prevent the covering layer 12 from becoming an obstacle to wireless communication and realize a suitable wireless communication environment. The coating layer 12 may be coated so as to cover the surface of the magnetic layer 11, or may be coated so as to cover not only the surface of the magnetic layer 11 but also the side surfaces.

  Such a covering layer 12 may be any non-conductive material. For example, resins such as polystyrene, polyethylene, polypropylene, polyamide, polycarbonate, polyacrylonitrile, polyurethane, polybutylene terephthalate, polynaphthalene terephthalate, polyester terephthalate, and ABS are used. , Recycled resin, biodegradable resin, modified resin, alloy, rubber, elastomer, paper, cloth, woven fabric, foam, leather, cellophane, and the like. In this embodiment, polyester terephthalate is used, but the present invention is not limited to this. Depending on the material to be selected, it is possible to impart heat resistance, chemical resistance, gas permeability resistance, flame retardancy, quasi-incombustibility, and incombustibility. Among them, the coating layer 12 of the present invention that can improve airtightness, waterproofness and mechanical strength while maintaining flexibility is most preferable. Moreover, you may utilize as a part or all of the coating layer 12 as it is, without peeling the material used for the support body. However, it is possible to add a conductive material, a dielectric material, a magnetic material, etc. to such an extent that the performance of the magnetic shield sheet 10 is not changed. In order to increase the reinforcing effect of the covering layer 12, reinforcing fillers (short fibers, long fibers, inorganic fillers, carbon, etc.) can be added.

  The covering layer 12 is formed by an arbitrary method such as lamination or molding. Usually, an adhesive or a pressure-sensitive adhesive is not used, but it may be used, or a reinforcing layer made of a non-conductive material such as a canvas or a net may be formed here.

  FIG. 2 is a cross-sectional view showing the non-contact IC card 15 in a simplified manner. A non-contact IC card 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) 17 electrically connected to the antenna element 16. Is a non-contact IC card 15. When this non-contact IC card 15 is used in the vicinity of a communication obstruction member 19 such as a metal plate or an antenna element of another non-contact IC card, the magnetic shield sheet 10 is provided between the non-contact IC card 15 and the communication obstruction member 19. .

  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. A in the drawing is an example, and communication from any direction other than A is possible. FIG. 2 shows, by a solid magnetic field distribution curve, a state in which communication by the electromagnetic induction method can be performed by the magnetic shield sheet 10 even in the vicinity of the communication disturbing member 19.

  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 non-contact IC card 15 is an electronic component that transmits and receives an electromagnetic wave signal using the antenna element 16. The non-contact IC card 15 may be a battery-driven tag 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 non-contact IC card 15 can be used in the vicinity of the communication disturbing 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 non-contact IC card 15 is provided such that the magnetic shield sheet 10 is interposed between the antenna element 16 and the communication disturbing member 19. In order to optimize communication, it is desirable to adjust the resonance frequency of the non-contact IC card 15.

  The magnetic shield sheet 10 shields an electromagnetic field by the magnetic layer 11 or the conductor layer 31, and of the two areas partitioned by the magnetic seal sheet 10, the electromagnetic field of one area leaks to the other area. It is possible to prevent the energy of the electromagnetic field in this region 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.

  More specifically, the magnetic layer 11 is made of a material having a large real part μ ′ of complex relative permeability. Therefore, when the magnetic layer 11 is provided in a magnetic field, for example, transmission from the antenna element 16 in FIG. As shown in the example of the magnetic field generated by the electromagnetic wave, the magnetic field lines 20 concentrate through the magnetic layer 11 and do not pass through the communication disturbing member 19 existing in the vicinity or are difficult to pass and are not easily affected. . Thus, by using the magnetic shield sheet 10, the magnetic field is shielded, 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 communication disturbing member 19 which is the other region. Can be prevented from leaking into the area where the

  When the antenna element 16 is provided at a position similar to the position shown in FIG. 2 and the magnetic shield sheet 10 is not provided, the magnetic field lines of the magnetic field due to the electromagnetic waves transmitted and received are, for example, as shown by the virtual line 21 in FIG. Then, the communication obstruction member 19 is passed. However, in reality, when the communication disturbing member 19 is made of metal, many magnetic field lines are bent so as to proceed in parallel with the communication disturbing member 19, and few enter the communication disturbing member 19. Rather, an induced current (eddy current) is generated on the surface of the communication disturbing member 19 by the magnetic lines of force. 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. When the communication disturbing member 19 is an antenna coil, the magnetic field lines penetrate the communication disturbing member 19 and cause a shift of the resonance frequency. On the other hand, by shielding the magnetic field using the magnetic shield sheet 10 having a large electric resistance, the energy of the magnetic field on the opposite side to the communication disturbing member 19 with respect to the magnetic shield sheet 10 is reduced by the communication disturbing member 19. To prevent that. Moreover, the interference between antenna coils can be reduced by combining the conductor layer 31 and the magnetic shield sheet 10 having a large electric resistance to shield the magnetic field. Therefore, the communication disturbing member 19 reduces 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 communication disturbing member 19 with respect to the magnetic shield sheet 10. prevent.

  Further, since the magnetic layer 11 is made of a material having a small imaginary part μ ″ of the complex relative permeability, even if magnetic flux passes through the magnetic layer 11, the energy of the energy in the magnetic layer 11 accompanying the passage of the magnetic layer 11 The loss can be suppressed to a small value, so that the magnetic layer 11 itself is prevented from losing the energy of the magnetic field even if the magnetic lines of force pass through the magnetic layer 11 in a concentrated manner. In addition, the magnetic layer 11 can prevent the interference of the magnetic field energy by the communication disturbing member 19 existing in the vicinity, suppress the loss by itself, and reduce the attenuation of the magnetic field energy as much as possible.

  The size of the magnetic layer 11 is not particularly limited as long as communication improvement of the antenna element 16 can be achieved. There may be a part between the antenna element 16 and the communication disturbing member 19. It is also possible to provide slits and slots.

  By interposing such a magnetic shield sheet 10 between the antenna element 16 and the communication disturbing 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 reduced. And the communication characteristics are prevented from being deteriorated due to interference from the communication disturbing member 19. Moreover, the magnetic shield sheet 10 itself for preventing the influence of the communication disturbing member 19 has a small magnetic loss. Therefore, the antenna element 16 can transmit and receive a long distance suitably. Therefore, even when the non-contact IC card 15 is provided in the vicinity of the communication blocking member 19, information can be wirelessly communicated between the information management device and the non-contact IC card 15, and transmitted from the information management device. The information represented by the electromagnetic wave signal can be stored in the non-contact IC card 15, and the information stored in the non-contact IC card 15 can be read out by the information management device.

  Further, the magnetic shield sheet 10 has a resonance frequency adjusting function of the non-contact IC card 15 between the communication disturbing member 19 and the non-contact IC card 15. The resonance frequency of the non-contact IC card 15 can be shifted by the complex relative permeability and thickness of the magnetic layer 11. For example, the resonance frequency can be adjusted only by the magnetic layer 11 without adding a matching circuit. It becomes possible.

  Adjustment of the Q value by the magnetic shield sheet 10 is also possible. The Q value is a measure representing the ease of collecting magnetic fields at the operating frequency of an electromagnetic induction antenna coil.

  In order to show the transmission / reception characteristics of the non-contact IC card 15, this Q value is evaluated by applying it to the peak value of the real part (R) of the impedance obtained by the material analyzer. A high Q value indicates that it is easy to collect a magnetic field for communication, and thus indicates high communication characteristics.

  In order to make the communication characteristics most suitable, it is necessary to adjust the resonance frequency to around f0 and to make the Q value (the real part (R) of impedance in the present invention) as high as possible. Since the magnetic layer 11 has a function of lowering the resonance frequency of the antenna coil 16, when the communication disturbing member 19 is a metal, the canceling effect of returning the resonance frequency shifted to a high frequency to f 0, and the communication disturbing member. When 19 is another antenna coil, it is possible to obtain an effect of returning a component having a high resonance frequency divided into two peaks to f0.

  When the communication disturbing member 19 is another antenna coil, the magnetic layer 11 and the conductor layer 31 can be used in combination. The conductor layer 31 has high electromagnetic shielding properties, and the resonance frequencies divided into two peaks can be combined into a single peak of high frequency. By adjusting the frequency with the magnetic layer 11 from this state, the real part μ ′ of the complex relative magnetic permeability can be lowered, compared with the case where only the magnetic layer 11 is used for the magnetic shield sheet 10, or the magnetic layer The thickness of 11 can be reduced. The frequency adjustment method using the magnetic layer 11 can be achieved by providing irregularities on the surface or providing slits or slots, and can also be achieved by changing the distance from the conductor layer 31.

  From the above, the magnetic shield sheet 10 has the antenna element 16 (antenna) such as housing the non-contact IC card 15 communicating at the same frequency in the same card case when performing wireless communication using electromagnetic waves of the communication frequency. Even when the communication disturbing member 19 is present in the vicinity of the coil), wireless communication is suitably performed by using electromagnetic waves of the communication frequency by being provided between the antenna element 16 (antenna coil) and the communication disturbing member 19. Can be made. Furthermore, since the magnetic shield sheet 10 has high mechanical strength, the magnetic layer 11 is not damaged or bent, so that the wireless communication environment is not impaired.

  Further, by providing different non-contact IC cards 15 with the magnetic shield sheet 10 sandwiched therebetween, it becomes possible to read the respective non-contact IC cards 15, and even if the non-contact IC cards 15 are not separated from each other, Communication between the contact IC card 15 and the reading device is possible. Depending on the configuration of the magnetic shield sheet 10, it is possible to provide anisotropy in communication characteristics such as one-side skimming prevention and other-side wireless communication.

  The magnetic shield sheet 10 has an overall thickness dimension T10 of 0.5 mm to 5 mm. If the thickness dimension T10 is smaller than 0.5 mm, sufficient mechanical strength cannot be obtained, and the magnetic shield sheet 10 cannot be prevented from being bent. When the magnetic shield sheet 10 is bent, a suitable wireless communication environment is impaired. Moreover, when the thickness dimension T10 is formed to be larger than 5 mm, it is difficult to accommodate in a card case or the like, and it is difficult to handle.

  Further, when the magnetic layer 11 and the conductor layer 31 themselves also use the covering layer 12, the magnetic shield sheet 10 can be further colored on the surface, printed, designed, and uneven, thereby making a highly designable card. It is also possible.

  FIG. 3 is a simplified cross-sectional view showing the magnetic shield 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 magnetic shield card 10 is the same as that of the first embodiment except that a laminated body 32 in which a magnetic layer 11 and a conductor layer 31 containing a metal are laminated instead of the magnetic layer 11 is used. The magnetic shield sheet 10 includes a laminated body 32 and a coating layer 12 that covers the entire laminated body 32. The laminate 32 is a laminate in which the magnetic layer 11 and the conductor layer 31 are laminated so as to be an outer layer.

  Since the conductor layer 31 is laminated on the magnetic layer 11, the magnetic shield sheet 10 is disposed near the non-contact IC card 15, such as being used by being superimposed on the non-contact IC card. The skimming of the non-contact IC card 15 can be prevented. Furthermore, since the magnetic shield sheet 10 is laminated such that the conductor layer 31 is sandwiched between the magnetic layers 11, the magnetic layer 11 is disposed between the non-contact IC card 15 and the conductor layer 31, The non-contact IC card 15 on the magnetic layer 11 side can ensure a suitable wireless communication environment. In order to improve wireless communication, it is preferable to adjust the resonance frequency at this stage.

  The conductor layer 31 is made of a material having high magnetic shielding properties. It is preferable that the magnetic shielding property is 20 dB or more against electromagnetic waves having a communication frequency. By doing so, the magnetic field shielding property from the opposite side to the transmission / reception direction A can be further improved.

  For the conductor layer 31, a metal (aluminum, copper, etc.), a conductive member, a conductive treatment material, or the like can be used. The conductor layer 31 has electromagnetic shielding properties and shifts the resonance frequency of the antenna coil of the non-contact IC card 15 to a high frequency to prevent wireless communication. Thereby, the skimming prevention effect is obtained. As the conductor layer 31, a normal metal such as Al or Cu can be used. If the conductivity is high, ink or paint may be used. In particular, when magnetic field shielding properties are required, the conductor layer 31 includes a magnetic metal layer, a magnetic ceramic layer, an Fe (iron) -based metal sheet, a Co-based sheet, a Ni-based sheet, stainless steel, or an Fe-based metal powder and a binder. A complex is used. As the material of the conductor layer 31 in this case, the material exemplified for the soft magnetic powder can be 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.

  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 5000. 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 may have an initial permeability of less than 5000. In general, a material having an initial permeability of 5000 or more is limited to permalloy, supermalloy, or 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 magnetic permeability is achieved at the expense of workability.

  On the other hand, the magnetic shield card of the present invention aims to emphasize workability rather than to ensure the desired magnetic shield property. In other words, the performance is stable even when a secondary process such as punching and bending the magnetic shield sheet is performed. Furthermore, even if an after-curing step for increasing the magnetic permeability is omitted, desired magnetic shielding properties can be exhibited.

  When the conductor layer 31 is made 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 thickness of the conductor layer 31 is preferably 500 μm or less, and particularly preferably 1 μm to 100 μm. The conductor layer 31 is not limited to a plate, foil, paint, or the like, and may be, for example, a material plated on a mesh or a nonwoven fabric, or may be fixed by vapor deposition, plating, adsorption, or the like.

  The magnetic shield effect is required to be 20 dB in a frequency range of 100 KHz to 1 GHz by a known method called KEC method or Advantest method. Preferably it is 30 dB or more. More preferably, it is 60 dB or more. In this frequency range, the magnetic layer 11 has a single layer configuration, and a desired magnetic shield effect (20 dB) cannot be obtained, and the conductor layer 31 is laminated.

  The conductor layer 31 may be a layer made of a material having high magnetic shielding properties, but is preferably made of, for example, one or more selected from magnetic metal, amorphous metal, magnetic stainless steel, and ferrite. Moreover, it is preferable that a magnetic metal consists of a metal or alloy containing 1 or more types chosen from iron, nickel, and cobalt. Those oxides may be used. By doing so, the magnetic shielding property of the conductor layer 31 can be improved, and skimming can be further prevented.

  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 magnetic layer 11 is used only on one side and an insulating layer having no magnetism is used on the other side instead of the magnetic layer 11 can be adopted.

  FIG. 4 is a simplified cross-sectional view showing a magnetic shield sheet 10 according to the third embodiment of the present invention. Parts corresponding to those of the second embodiment shown in FIG. 3 are denoted by the same reference numerals, and description thereof is omitted to avoid duplication.

  The magnetic shield sheet 10 is the same as that of the second embodiment except that the laminated body 32 is a laminated body in which both outer layers are laminated so that the magnetic layer 11 and the conductor layer 31 therebetween.

  Further, since the magnetic shield sheet 10 is laminated such that the conductor layer 31 is sandwiched between the magnetic layers 11, if different non-contact IC cards are provided with the magnetic shield sheet 10 interposed therebetween, the respective tags and conductor layers are arranged. The magnetic layer 11 is disposed between the magnetic layer 11 and the magnetic layer 11. At this stage, the resonance frequency can be adjusted. Therefore, by providing different tags with the magnetic shield sheet 10 in between, the non-contact IC card and the reading device can be provided without separating the non-contact IC cards regardless of the transmission / reception directions of the respective non-contact IC cards. Communication with is possible.

  Further, there may or may not be an adhesive layer, an adhesive layer, a dielectric layer, or the like between the conductor layer 31 and the magnetic layer 11. Further, a configuration in which the magnetic layer 11 is substantially connected while the magnetic layer 11 is disposed on both sides of the conductor layer 31 using a mesh or perforated conductor layer 31 is also possible. The optimum configuration can be selected while evaluating the communication characteristics of the non-contact IC card.

  In the magnetic shield card 10, when the non-contact IC card 15 is arranged on the magnetic layer 11 side, the magnetic layer 11 is arranged between the non-contact IC card 15 and the conductor layer 31. Communication between the contact IC card 15 and the reading device is possible.

  The coating layer 12 of the second and third embodiments may be coated so as to cover the surface of the magnetic layer 11, or may be coated so as to cover not only the surface of the magnetic layer 11 but also the side surfaces. However, it is preferable that the magnetic layer 11 is coated so as to cover not only the surface but also the side surfaces. By doing so, it can prevent that the conductor layer 31 rusts.

  The magnetic shield sheet 10 of the present invention is not limited to the card size and can be used in various sizes. In addition to the card, it can be used as an antenna coil laminated body or an antenna coil integrated with the antenna coil.

  When the conductor layer 31 is used as the support, a sheet having magnetic shielding properties and noise suppression effects can be obtained by laminating the magnetic layer 11 in the coating process. The magnetic layer 11 also has an effect as a rust preventive agent for the conductor layer 31. In addition, the conductor layer 31 can be subjected to an adhesion treatment as necessary.

  Furthermore, the magnetic shield sheet 10 can be used as an electronic device in which the resonance frequency of the antenna coil is adjusted by providing a non-contact IC card 15 inside the covering layer 12 (or outside the covering layer 12 or the covering layer 12 itself). Good. Examples of the electronic device include a small electronic device such as a button-type antenna. Such an electronic device includes, for example, a laminate 32 in which a magnetic layer 11 and an antenna for transmitting and receiving an electromagnetic wave signal are stacked so that the magnetic layer 11 is on the opposite side of the antenna transmission / reception direction. The coating layer 12 may be configured to include a non-conductive material and at least partially cover the laminate 32. In addition, such an electronic device includes, for example, a magnetic layer, a conductor layer 31 containing metal, and antenna means for transmitting and receiving electromagnetic wave signals, and at least one outer layer serves as antenna means, and the magnetic layer 11 Includes a laminate 32 laminated so as to be disposed between the antenna means and the conductor layer 31, and a covering layer 12 made of a non-conductive material and covering at least partially the laminate 32. It may be comprised.

  By doing so, if the electronic device is located on the magnetic layer 11 side, it can suitably perform wireless communication using an electromagnetic wave having an incoming communication frequency. Furthermore, in order to increase the communication distance on the magnetic layer 11 side, the resonance frequency and Q value of the antenna coil laminated on the magnetic layer 11 can be adjusted. As a method of adjustment, the C component may be applied in a circuit manner, or the complex relative permeability or thickness of the magnetic layer 11 may be adjusted. Furthermore, this electronic device can be miniaturized by incorporating the antenna means. Moreover, when the conductor layer 31 is laminated | stacked, skimming can also be prevented.

  FIG. 5 is a simplified cross-sectional view showing a storage container 41 according to the fourth embodiment of the present invention. The storage container 41 is, for example, a card case, a wallet, a regular case, a memo pad, a notebook, a bag, and clothes. In the present embodiment, the storage container 41 includes a first storage portion 43 and a second storage portion 44 that store the non-contact IC card 42. The first housing portion 43 and the second housing portion 44 are formed of the magnetic shield card 10 as a partition member between the first housing portion 43 and the second housing portion 44. By doing so, even if the non-contact IC card 42 is accommodated in each of the first accommodating portion 43 and the second accommodating portion 44, the non-contact IC card 42 to be used is removed from the first accommodating portion 43 and the second accommodating portion 44. Communication between the non-contact IC card 42 and the reading device is possible without taking out and in the accommodated state. Further, skimming of the non-contact IC card 42 can be prevented. The configuration in FIG. 5 is an example, and the housing portion may be completely covered, partially covered, or housed only through a simple holder.

  In the above-described embodiment, the storage container 41 includes the storage portion in which the member that partitions the first storage portion 43 and the second storage portion 44 is formed of the magnetic shield sheet 10. What is necessary is just to be comprised including. For example, the magnetic shield sheet 10 may be contained in a partition member made of cloth and leather constituting the card case. Further, there may be one accommodating portion. By doing so, it is possible to prevent skimming from the side opposite to the transmission / reception direction while ensuring a suitable wireless communication environment of the non-contact IC card 42. The storage container 41 is realized by, for example, a card case, a wallet, a regular case, a memo pad, a notebook, a bag, and clothes.

(Create magnetic layer)
Using HNBR (Zetpol made by Nippon Zeon) as a binder, adding 40% by volume of flat Fe—Ni—Cr—Si alloy powder (JEM powder made by Mitsubishi Materials) as soft magnetic metal powder, zinc stearate as a dispersant, cross-linking After adding an appropriate amount of an agent (peroxide), a magnetic paint dissolved in methyl isobutyl ketone (MIBK) / methyl ethyl ketone (MEK) solution is prepared and applied onto PET (polyethylene terephthalate, release support) by the doctor blade method. And sheet forming. Subsequently, the peeling support was peeled off, and a magnetic layer 11 having a thickness of 150 μm was obtained by a hot press method. The shield layer 11 was laminated with a PET film (25 μm thick) as a coating layer 12 to obtain a molded magnetic shield sheet 10. This example corresponds to the first embodiment.

  The magnetic layer 11 shown in Table 1 has the same soft magnetic metal powder, but uses a urethane resin as a binder and creates a sheet by a coating method. Thicknesses of 35 μm, 50 μm, and 100 μm are in a roll shape and do not use a hot press method. A 100 μm thickness was prepared by thermally laminating a 50 μm thick sheet. However, the sheet having a thickness of 250 μm is prepared by a hot press method.

Example 1
The magnetic layer 11 (150 μm thickness) using HNBR as a binder and an aluminum (Al) foil were laminated with an adhesive (25 μm), and in this state, laminated with a PET film (25 μm thickness) and molded. A magnetic shield sheet 10 was obtained. This example corresponds to the third embodiment.

(Example 2)
The magnetic layer 11 of Example 1 (150 μm thick) and metal (Fe) foil (Toyo Kohan Foil Top, 50 μm thickness) are laminated via an adhesive (25 μm), and further laminated with a PET film (25 μm thickness). The magnetic shield sheet 10 was processed and molded. This example corresponds to the third embodiment.

(Example 3)
The magnetic layer 11 (150 μm thickness) of Example 1 was laminated on both sides of the metal (Fe) foil of Example 3 (Foil Top, manufactured by Toyo Kohan Co., Ltd., 50 μm thickness) via an adhesive (30 μm). Furthermore, it was made into a magnetic shield sheet laminated with a PET film and molded. This example corresponds to the second embodiment.

(Comparative Example 1)
A copper plate (500 μm) was laminated with a PET film to form a magnetic shield sheet 10 which was molded.

(Comparative Example 2)
The non-contact IC card 15 was laminated at the position where the antenna coil overlapped.

  Examples 1 to 14 and Comparative Examples 1 to 7 were subjected to material constant measurement, wireless communication performance measurement, magnetic shielding property measurement, electric field shielding property measurement, surface resistivity measurement, mechanical strength measurement, and salt spray test.

<Measurement of material constant>
The material constant includes a real part μ ′ of the complex relative permeability, an imaginary part μ ″ of the complex relative permeability, a real part ε ′ of the complex relative permittivity, and an imaginary part ε ″ of the complex relative permittivity. The measurement was carried out by ring processing (φ7 × φ3) of the material and the coaxial tube method. The measuring instrument uses a material analyzer E4991A and a network analyzer HP8720ES for frequencies from 1 MHz to 10 GHz.

  FIG. 6 is a graph showing the measurement results of the material constants (μ ′, μ ″, ε ′, ε ″) of the magnetic layer 11 (thickness of 150 μm) in Example 1. As can be seen from FIG. 6, the real part μ ′ of the complex relative permeability in the 13.56 MHz band is 58.7, the imaginary part μ ″ is 2.6, the real part ε ′ of the complex relative permittivity is 555.6, The imaginary part ε ″ was 141.7.

  FIG. 7 is a graph showing the measurement results of the material constants (μ ′, μ ″, ε ′, ε ″) of the magnetic layer 11 (35 μm thickness) of Example 11 and Comparative Examples 3, 6, and 7. The real part μ ′ of the complex relative permeability in the 13.56 MHz band is 32.5, the imaginary part μ ″ is 1.4, the real part ε ′ of the complex relative permittivity is 363.2, and the imaginary part ε ″ is 35. .7. 8 shows the measurement results of the material constants (μ ′, μ ″) of the magnetic layer 11 (50 μm thickness and 100 μm thickness) of Examples 5, 6, 8, 9, 12, 13 and Comparative Examples 4 and 5. The real part μ ′ of the complex relative permeability in the 13.56 MHz band is 39.5, the imaginary part μ ″ is 2.2, the real part ε ′ of the complex relative permittivity is 440.3, and the imaginary part. ε ″ was 56.5. Further, FIG. 9 shows the measurement results of the material constants (μ ′, μ ″, ε ′, ε ″) of the magnetic layer 11 (250 μm thickness) of Examples 4, 7, 10, and 14. The real part μ ′ of the complex relative permeability in the 13.56 MHz band is 47.1, the imaginary part μ ″ is 1.3, the real part ε ′ of the complex relative permittivity is 885.3, and There were 198 imaginary parts ε ”.

  Therefore, the material constant of the magnetic layer 11 of the example and the comparative example is such that the real part μ ′ of the complex relative permeability at the communication frequency (in this example, 13.56 MHz band) is 30 or more, and the complex relative permeability. The permeability loss term tan δμ (= μ ″ / μ ′), which is a value obtained by dividing the imaginary part μ ″ by the real part μ ′ of the complex relative permeability, is 0.2 or less. In order to obtain the effect of the magnetic layer 11 of this embodiment, it is important that the real part μ ′ and the imaginary part μ ″ of the complex relative permeability at the communication frequency have a relationship of high μ ′ and low μ ″. It is.

  The reason why the numerical values defined in the claims can be realized in the material constant is as follows. The first reason is that a flat soft magnetic metal (JEM powder, sendust, etc.) is used. The second reason is that the soft magnetic metal is contained in an amount of 20% by volume or more with respect to the binder (polymer) without breaking the flat soft magnetic metal shape (distortion, breakage, etc.). This is because they are oriented. The meaning of the first and second reasons is that by dispersing the flat soft magnetic metal powder in this way, first, the soft magnetic metal powder is wrapped with a binder which is an insulating material, so that the insulating (high) Resistance) and flexibility, and flat soft magnetic metal powder is oriented and arranged in the plane direction, allowing magnetic flux to enter the magnetic layer 11 in a substantially vertical direction but allowing it to pass. This is because the magnetic property anisotropy of collecting and facilitating passage of the substantially horizontal magnetic flux can be provided. The third reason is that the frequency at which the real part μ ′ of the complex relative permeability μ of the sheet decreases is increased (for example, 50 MHz or more), so that the imaginary part μ ”of the complex relative permeability μ of the communication frequency is increased. (Achieved by studying the blending method, metal composition ratio, and particle size distribution).

  In combination with the above three reasons, it is possible to obtain preferable specific material constants μ ′ and μ ″ in the magnetic layer 11 of each example using the present material. It is designed to increase both the real part μ ′ and the imaginary part μ ″ of the complex relative permeability at frequency. The present invention clearly distinguishes the technology from the viewpoint of energy loss in 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 band). In addition, the case where the communication frequency is in the 13.56 MHz band has been described in detail, but a preferable specific material constant μ ′ is preferable even when the communication frequency is 100 kHz or more and 30 GHz or less. , Μ ”. Therefore, wireless communication can be suitably performed using electromagnetic waves of these communication frequencies (specific frequencies).

<Measurement of wireless communication performance>
The wireless communication performance was measured by the following two methods.

(1) Communication distance measurement As the non-contact IC card 61, a Texas Instruments tag inlet "Tag-it ^TM HF-1" (RI-I02-112A) (ISO / IEC 15692-2, 3) is used. As the reading device 62, an Omron reader / writer V720S-BC5D4 was used to measure the communication distance between the non-contact IC card 61 and the reading device 62.

  FIG. 10 is a schematic diagram showing a method for measuring a communication distance by the RFID system OMRON reader 62 and the non-contact IC card 61. As the communication distance, the following two types of communication distances were measured. As shown in FIG. 10 (a), the measurement method is such that the sheet body 10 is arranged on the non-contact IC card 61 through the base 63, and further the metal foil 64 (iron foil, aluminum foil) is arranged, In this state, the communication distance L1 between the non-contact IC card 61 and the reader 62 was measured. In this case, the communication disturbing member 19 is a metal. Further, as shown in FIG. 10B, two non-contact IC cards 61 are arranged on both sides of the magnetic shield card 10 so as to overlap each other via a base material 63, and in this state, the non-contact IC card 61 and the reading are read. The communication distance L2 between the devices 62 was measured. In this case, the communication disturbing member 19 is another non-contact IC card.

  The communication distance measured with only one non-contact IC card 61 and no communication obstructing member (in free space) was 29 cm. On the other hand, when the magnetic shield sheet 10 was not interposed, the communication distance L1 was 0 cm, and the communication distance was shortened. The communication distance L1 when the magnetic shield sheet 10 was interposed was measured. In addition, it was read from each direction of the non-contact IC card 61 on both surfaces of the magnetic shield sheet 10, and it was confirmed whether each non-contact IC card 61 could be read.

(2) Mutual inductance measurement Resonant frequency and mutual inductance of the non-contact IC card 61 when the non-contact IC card 61 and the magnetic shield sheet 10 are stacked and communication between coils is performed (the real part of the impedance in the table) (R)) was measured by attaching a loop antenna to the material analyzer E4991A. 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 19 as shown in FIG. 10A is a metal and the case where the communication obstruction member 19 as shown in FIG. 10B is another non-contact IC card 61. The results are shown in Table 1. Further, the case where the magnetic shield sheet 10 was not used was referred to as Comparative Examples 1 and 2.

  FIG. 11 is a graph showing the resonance frequency and the real part (R) of the impedance when the communication disturbing member 19 is a metal, and FIG. 12 is a graph when the communication disturbing member 19 is another non-contact IC card 61. It is a graph which shows the real part (R) of a resonant frequency and an impedance. In the case of Comparative Example 2, when a metal was brought close to the non-contact IC card 61, the resonance frequency shifted from the 13 MHz band to the vicinity of 28 MHz, and communication with the 13.56 MHz band reader / writer became impossible. Even when the non-contact IC card 61 is overlaid, the resonance frequency is divided into 6 MHz and 24 MHz, and communication is impossible. The adjustment result of the resonance frequency of the non-contact IC card 61 by the magnetic shield sheet 10 was confirmed.

  From the evaluation results of the wireless communication performance shown in Table 1, as the influence on the antenna coil of the non-contact IC card 61, the behavior is different between the case where the communication blocking member 19 is a metal and the case of another non-contact IC card 61. I understood. In this experiment, the resonance frequency of the reader / writer is fixed at 13.56 MHz.

  In the case of metal (including magnetic material), the resonance frequency of the non-contact IC card 61 antenna coil greatly deviates from the vicinity of 13.56 MHz in the free space to, for example, 28 MHz, on the high frequency side, and the real part (R) of the impedance decreases. Also became larger.

  On the other hand, in the case of superimposing the non-contact IC card 61, the resonance frequency is divided, but it is often shifted below 13.56 MHz and above 13.56 MHz. This phenomenon is called bimodality. This is because the resonance frequency was shifted to 12.0 MHz and 17.1 MHz even when a gap of 1 cm was given to the non-contact IC card 61.

  Here, the resonance frequency (peak value) and the real part (R) result of impedance in Table 1 are measured between the non-contact IC card 61 and the loop antenna, and are evaluations of mutual inductance. In the wireless communication characteristics, the communication distance with the reader / writer is evaluated. In this case, the mutual inductance is required. Therefore, it can be said that the resonance frequency (peak value) measurement this time corresponds to the result of the communication distance.

  The effect of the magnetic layer 11 (magnetic shield sheet 10) in the case of metal is to lower the resonant frequency shifted to a high frequency, bring it close to the communicable 13 MHz band, and restore the real part (R) of the impedance It was to let you. The effect of lowering the resonance frequency of the magnetic layer 11 is determined by the magnetic permeability and the sheet thickness, but it is necessary to note that if the matching circuit is not used, it will be lowered too much. However, in the configuration of the example, the resonance frequency can be brought close to the communication frequency, and the magnetic layer 11 (magnetic shield sheet 10) having a high electric resistance value can be said to be an essential component. From this result, it is understood that if a metal is brought near the non-contact IC card 61, the resonance frequency is greatly shifted to the high frequency side, and the real part (R) of the impedance is lowered, so that wireless communication becomes impossible. It was. That is, the effect of the conductor layer 31 is that a skimming prevention effect can be imparted and a resonance frequency is provided on the higher frequency side.

  The effect of the magnetic layer 11 (magnetic shield sheet 10) on the case of superimposing one non-contact IC card 61 is that the function of lowering the resonance frequency due to the magnetic permeability of the magnetic layer 11 may have an adverse effect. However, when a gap corresponding to the thickness of the magnetic shield sheet 10 was provided and the magnetic layer 11 was inserted, communication improvement was possible. It can be said that this demonstrates the original function of the magnetic layer 11 (the magnetic shield sheet 10) that concentrates and passes the magnetic field, rather than the effect of shifting the resonance frequency relative to the case of metal.

  In this case, as a configuration of the magnetic shield sheet 10, a conductor layer 31 (metal, magnetic metal, or conductive material can be used) is disposed inside as in the third embodiment, and resonance is caused by the magnetic layers 11 on both sides thereof. It was most effective to adjust the frequency (in the present invention, adjustment by the magnetic permeability and thickness of the magnetic layer 11). As a result, it was confirmed that even if the non-contact IC cards 61 on both sides approach each other, both the non-contact IC cards 61 can be read due to the magnetic shield sheet 10 between them. Further, when the outer layers are the magnetic layer 11 and the conductor layer 31, the non-contact IC card 61 on the magnetic material layer 11 side can be read from any direction, but the non-contact IC card 61 on the conductor layer 31 side can be read from any direction. It was found that this side has an effect of preventing skimming. When the non-contact IC card 61 is approaching, the peak of the resonance frequency is often divided into two, and the peak can be made closer or one by the magnetic shield sheet 10, but the communication distance is increased. It was difficult to stretch. When the communication distance of one non-contact IC card 61 was eliminated in the conductor layer 31 as in Examples 2 and 3, the communication distance of the non-contact IC card 61 on the other magnetic layer 11 side was optimized.

  Further, the interference result due to the overlap of the non-contact IC card 61 and the communication improvement effect of the magnetic shield sheet 10 against the interference result were measured. That is, the communication characteristics when the communication disturbing member is an overlapping antenna coil are evaluated. FIG. 13 shows the configuration of the magnetic shield sheet 10 whose communication characteristics were measured in the test of FIG. The magnetic layer 11 is the magnetic shield sheet 10 (configuration a), the magnetic layer 11 and the conductor layer 31 are the magnetic shield sheet 10 (configuration b), the magnetic layer 11 / the conductive layer 31 / the magnetic layer. 11 was prepared as a magnetic shield sheet 10 (configuration c), and resonance characteristics were measured and communication characteristics were evaluated.

  14 to 16 are graphs showing the resonance frequency and the real part (R) of the impedance when the communication disturbing member 19 is another non-contact IC card 61. FIG. 14 shows the result of the configuration a (Example 4), FIG. 15 shows the result of the configuration b (Examples 5 to 7), and FIG. 16 shows the result of the configuration c (Examples 8 to 10). Show.

  First, in the case of the configuration a, it has been found that, by increasing the magnetic permeability of the magnetic layer 11 and increasing the sheet thickness, the bimodality of the resonance peak cannot be eliminated, but the communication can be improved above a certain threshold. In this case, communication is possible when the product of the magnetic permeability μ ′ and the sheet thickness t (μm) exceeds 10,000. This is because the resonance peak shifted to a high frequency when the non-contact IC card 61 overlaps is adjusted to be lowered to the communication frequency (f0) by the magnetic layer 11, and the real part of the impedance by the magnetic layer 11 ( R) is based on an improvement effect and an electromagnetic coupling reduction effect between the non-contact IC cards 61.

  In the case of the configuration b and the configuration d, the effects of the conductor layer 31 and the magnetic layer 11 were combined, and a communication improvement effect was obtained. Since the conductor layer 31 has a high electromagnetic shielding effect and an effect of shifting the resonance frequency to a high frequency, the resonance frequency lowering effect by the magnetic layer 11 can be utilized more effectively. The magnetic layer 11 for adjusting the frequency and improving the real part (R) of the impedance was able to obtain a communication improvement effect when the product of the magnetic permeability μ ′ and the sheet thickness (μm) t exceeded 2,000. .

  From this example, it was found that the magnetic layer 11 is effective as a communication improvement measure when the non-contact IC cards 61 overlap, but the communication improvement cannot be achieved simply by using the magnetic layer 11. Communication improvement is obtained only by giving an appropriate magnetic permeability μ ′ and thickness to the magnetic layer 11 and adjusting the resonance frequency and mutual inductance (the real part (R) of the impedance of the present invention). The adjustment by the magnetic layer 11 depends on the distance from the conductor layer 31 and the non-contact IC card 61, the shape effect of the magnetic layer 11 such as irregularities, slits / slots, etc., and the lamination effect. The factors to be used were permeability μ ′ and thickness t.

  The coating layer 12 of the magnetic shield sheet 10 may or may not be present. However, the role as a protective layer is important, and in many cases, the magnetic shield sheet 10 is provided with a coating layer 12 made of a resin.

<Measurement of magnetic (magnetic field) shielding>
The magnetic (magnetic field) shielding property at a frequency of 100 KHz to 1 GHz was measured by the Advantest method. FIG. 17 is a graph showing the results of magnetic field shielding properties of the magnetic shield sheet 10 of Example 2. As can be seen from FIG. 17, it was confirmed that the magnetic field shielding property was as high as 12 dB at a frequency of 125 KHz to 135 KHz and over 60 dB in a 13 MHz band. It was confirmed that the magnetic shield sheet 10 of Example 3 has 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 can sufficiently prevent electromagnetic wave interference (other wave interference). The electric field shielding property not shown here has a high shielding property even without using a magnetic metal. In this configuration, the electric field shielding property exceeds 40 dB at each frequency.

  Moreover, the measurement result of the magnetic field shielding property by the Advantest method of the magnetic shielding sheet 10 which is Example 3 has a high magnetic field shielding property of 12 dB at a frequency of 125 KHz to 135 KHz and over 60 dB in a 13 MHz band.

<Measurement of surface resistivity>
In order to evaluate the conductivity, the surface resistivity (based on JIS K6911) was measured. As a measuring instrument, Hiresta MCP-HT450 made by Mitsubishi Chemical was used. The magnetic layer 11 of this example (Example 1) was 5.1 × 10 ⁷ Ω / □. The magnetic layer 11 used in Comparative Examples 3, 6 and 7 was 2 × 10 ⁸ Ω / □, and the magnetic layer 11 used in Comparative Examples 4 and Examples 6 and 8 was 2 × 10 ⁴ Ω / □. The magnetic layer 11 used in Examples 6 and 9 was 5 × 10 ⁵ Ω / □, and the magnetic layer 11 used in Examples 4, 7, and 10 was 6 × 10 ⁵ Ω / □.

<Measuring mechanical strength>
In accordance with JIS K6251, the magnetic layer 11 (150 μm thickness) of Example 1 alone and the magnetic shield sheet 10 of Example 1 were subjected to a tensile test. The dumbbell shape is No. 1. With respect to the magnetic shield sheet 10, dumbbell punching was performed after molding. The tensile strength of the magnetic layer 11 (150 μm thickness) of Example 1 was 6.2 MPa, but the magnetic shield sheet 10 of Example 1 almost doubled to 11.5 MPa.

<Evaluation of flexibility>
The magnetic layer 11 was wound around a rod having a diameter of 3 mm, and it was confirmed whether or not the sheet was broken or cracked. The magnetic layer 11 of the present invention was confirmed to be flexible without any breakage or cracking, including those having a thickness of 250 μm.

<Salt spray test>
Rust prevention was evaluated by a salt spray test. Specifically, a salt spray tester (CASSER-ISO-3 manufactured by Suga Test Instruments Co., Ltd.) is used under the following test conditions, and evaluation is performed by visually observing the surfaces of the magnetic layer 11 and the magnetic shield sheet 10 after the test. did. The purpose of this test is to evaluate the improvement in airtightness and waterproofness by the coating layer 12. In particular, it has been confirmed that the rust prevention is improved when the conductor layer 31 is used.

Test conditions Sodium chloride solution concentration: 5 ± 0.5% by weight
Spray chamber temperature: 35 ± 2 ° C
Test time: 48 hours

  As a result, there was no rust in the magnetic shield sheet 10 not using the conductor layer 31, and rust generation was observed on the side surface of the conductor layer 31 using iron foil (thickness: 50 μm) in the absence of the coating layer 12. . On the other hand, when the coating layer 12 was provided so as to cover at least the side surface, rust generation was eliminated.

  The reader / writer used in the present invention is a type capable of long-distance communication with high output. This is supported by the fact that the communication distance used for the non-contact IC card alone was 29 cm. Actually, in a ticket gate system for a transportation system, a non-contact IC card is generally used in contact with a communication distance of 15 cm or less. By the way, in Examples 4 and 8 to 14 of the present invention, there was a result of wrapping around and reading. Also, in Examples 5 to 7, when reading from the conductor layer 31 side with a reader / writer, the non-contact IC card 61 on the magnetic layer 11 on the back side wraps around and reads. This is a result that depends on the radio wave arrival distance of the reader / writer, that is, the output, and reading and wrapping around does not mean that communication fails. In our experiments, no wraparound phenomenon was seen when using a handy type small reader. In evaluating the present invention, first, the result that the card facing the reader / writer can be read accurately is important.

  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. 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 magnetic shielding sheet 10 which is the 1st Embodiment of this invention. It is sectional drawing which simplifies and shows the non-contact IC card. It is sectional drawing which simplifies and shows the magnetic shielding sheet 10 which is the 2nd Embodiment of this invention. It is sectional drawing which simplifies and shows the magnetic shielding sheet 10 which is the 3rd Embodiment of this invention. It is sectional drawing which simplifies and shows the storage container 41 which is the 4th Embodiment of this invention. 4 is a graph showing measurement results of material constants (μ ′, μ ″, ε ′, ε ″) of a magnetic layer 11 (150 μm thick) in Example 1. 6 is a graph showing measurement results of material constants (μ ′, μ ″, ε ′, ε ″) of a magnetic layer 11 (thickness of 35 μm). 6 is a graph showing measurement results of material constants (μ ′, μ ″) of a magnetic layer 11 (thickness of 50 μm, thickness of 100 μm). 7 is a graph showing measurement results of material constants (μ ′, μ ″, ε ′, ε ″) of a magnetic layer 11 (250 μm thick). FIG. 6 is a schematic diagram showing a method for measuring a communication distance by the RFID system OMRON reader 62 and the non-contact IC card 61. It is a graph which shows the real part (R) of the resonant frequency and impedance when the communication disturbance member 19 is a metal. It is a graph which shows the resonant frequency in case the communication obstruction member 19 is another non-contact IC card 61. FIG. It is a figure which shows the structure of the magnetic shield sheet 10 which measured the communication improvement effect. It is a graph which shows the real part (R) of the resonant frequency and impedance when the communication disturbance member 19 is another non-contact IC card 61. It is a graph which shows the real part (R) of the resonant frequency and impedance when the communication disturbance member 19 is another non-contact IC card 61. It is a graph which shows the real part (R) of the resonant frequency and impedance when the communication disturbance member 19 is another non-contact IC card 61. It is a graph which shows the result of the magnetic field shielding property of the magnetic shielding sheet 10 which is Example 2. FIG. It is a figure which shows the structure of a non-contact IC card.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Magnetic shield sheet 11 Magnetic body layer 12 Covering layer 15,61 Non-contact IC card 16 Antenna element 17 IC
DESCRIPTION OF SYMBOLS 18 Virtual surface 19 Communication obstruction member 20 Magnetic field line 21 Virtual line 31 Conductor layer 32 Laminate body 41 Receptacle container 42 Non-contact IC card 43 First accommodating part 44 Second accommodating part 62 Reading device 63 Base material 64 Metal foil

Claims (10)

A non-contact IC card capable of non-contact communication with an external device is a magnetic shield sheet that improves communication characteristics when used in the presence of overlapping,
The magnetic material layer has a real part μ ′ of a complex relative permeability with respect to electromagnetic waves of a communication frequency and a magnetic material layer thickness t (μm).
μ ′ × t> 10,000
And
A magnetic shield sheet that is arranged between non-contact IC cards and improves communication characteristics by a resonance frequency adjusting means that at least a high frequency component of a resonance frequency is made to coincide with or approach the resonance frequency f0 that the non-contact IC card originally has. A non-contact IC card capable of non-contact communication with an external device is a magnetic shield sheet that improves communication characteristics when used in the presence of overlapping,
The magnetic material layer / conductor layer and the magnetic material layer / conductor layer / magnetic material layer, wherein the magnetic material layer has a real part μ ′ of complex relative permeability with respect to electromagnetic waves of communication frequency, and a magnetic material layer thickness t ( μm)
μ ’× t> 2,000
And
A magnetic shield sheet that is arranged between non-contact IC cards and improves communication characteristics by a resonance frequency adjusting means that at least a high frequency component of a resonance frequency is made to coincide with or approach the resonance frequency f0 that the non-contact IC card originally has. For an electromagnetic wave having a communication frequency, the real part μ ′ of the complex relative permeability is 30 or more, and the value tan δ _μ obtained by dividing the imaginary part μ ″ of the complex relative permeability by the real part μ ′ of the complex relative permeability is , with more than 0.2, the magnetic shield sheet according to claim 1 or 2, wherein the surface resistivity has the magnetic layer is 10 ⁴ Ω / □ or more. The resonant frequency and the communication frequency is, the magnetic shield card according to any one of claims 1-3, characterized in that at 100kHz or 30GHz or less. The magnetic 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 with respect to the binder, and is dispersed in an oriented state. The magnetic shield sheet according to claim 1 , wherein the magnetic shield sheet is provided. 3. The magnetic shield sheet according to claim 2 , wherein the conductor layer has a magnetic shield property of 20 dB or more according to a KEC method or an Advantest method with respect to electromagnetic waves of the communication frequency. The magnetic shield sheet according to claim 2 , wherein the conductor layer is made of at least one selected from magnetic metal, amorphous metal, magnetic stainless steel, and ferrite. Magnetic shield sheet according to thickness of any one of claims 1-7, characterized in that at 0.05mm 5mm or more or less. The magnetic shield sheet according to any one of claims 1 to 8 is disposed between the non-contact IC cards, and at least a high frequency component of the resonance frequency is made to coincide with or approach the resonance frequency f0 inherent to the non-contact IC card. A non-contact IC card communication improvement method characterized in that communication characteristics are improved. Contactless IC card accommodating container for storing the non-contact IC card communication improving apparatus using the magnetic shield sheet according to any one of claims 1-8.

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