JP2006293504A - Reader/writer for ic card - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reader/writer for reducing any unnecessary radiation noise to the outside by efficiently supplying a magnetic flux to an IC card to prevent it from being leaked to the outside by a ferrite core having the function of an antenna. <P>SOLUTION: This reader/writer 110 is provided with: a reader/writer control part 100 for performing the transmission of a conveyance power based on a predetermined modulation/demodulation system and the transfer of data with an IC card 200 through a loop antenna, which is not shown, provided in the IC card 200; a loop coil 9 for mediating the propagation of a carrier for power to the IC card 200 and the transfer of data with the IC card 200; and a ferrite core 14 around which a loop coil 9 is at least partially wound for deriving a magnetic field to be generated from the loop coil 9 as a magnetic flux 13. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an IC card reader / writer, and more particularly to a technique for reducing unnecessary radiation noise radiated from an IC card reader / writer.

In recent years, information recording media called IC cards have been widely available on the market. The IC card is a generic name for cards having a card shape such as a credit card, a bank card, a point card, or a sheet shape, and an IC (Integrated Circuit) incorporated in the card. Among them, non-contact type IC cards (hereinafter simply referred to as IC cards) are used as commuter passes or prepaid tickets used when entering or leaving electric railway stations. It is adopted in. In recent years, IC cards have been used everywhere, and it has become possible to purchase duty-free products with credit cards, for example, using a reader / writer provided not only on the ground but also in the aircraft. However, since IC cards exchange data with radio waves, the strength of transmission power is regulated by the domestic radio law, and the level of unnecessary radiation noise for electronic devices to prevent malfunction of other devices is regulated in each country. ing. For example, there are VCCI standards in Japan, UL standards in North America, and VDE standards in Europe, which cannot be sold or used unless the standards of each country are satisfied. In particular, in hospitals, test measurement rooms, and aircraft, malfunctions of equipment may adversely affect human life, measurement results, etc., so it is necessary to strictly suppress unnecessary radiation noise.
Therefore, as a conventional technique for suppressing unnecessary radiation noise, Patent Document 1 discloses an electromagnetic shield layer that shields leakage magnetic flux generated in a non-contact type transmission / reception path in order to prevent leakage magnetic flux and digital noise from being radiated to the outside of the apparatus. And a reader / writer in which both a digital noise absorbing layer for absorbing digital noise generated inside the (shared) IC card is provided outside the IC card holder.
JP 2004-102747 A

However, the prior art disclosed in Patent Document 1 covers the periphery with an electromagnetic shield layer and a digital noise absorption layer in order to suppress unnecessary radiation noise radiated from the card reader / writer device. It is electromagnetically attenuated. For this reason, an electromagnetic shield layer and a digital noise absorbing layer are required in addition to the original reader / writer components, which causes a problem that the cost of the device increases and the size of the device also increases.
In view of such problems, the present invention provides a reader / writer that reduces unnecessary radiation noise to the outside by efficiently supplying magnetic flux to an IC card and preventing leakage to the outside by using a ferrite core having an antenna function. The purpose is to do.

In order to solve such a problem, the present invention provides transmission of carrier power and transmission / reception of data based on a predetermined modulation / demodulation method to / from an IC card via a loop antenna provided in the IC card. In an IC card reader / writer, a loop coil that mediates propagation of a power carrier wave to the IC card and exchange of data with the IC card, and a magnetic field generated from the loop coil wrapped around the loop coil at least partially Magnetic flux introducing means for guiding the magnetic flux as magnetic flux, and the magnetic flux introducing means has a configuration capable of supplying a magnetic flux enabling at least communication with the IC card to the loop antenna on the IC card side. And
In the reader / writer of the present invention, the antenna is coiled and the coil is wound around a magnetic material. Thereby, the magnetic field generated in the coil flows as a magnetic flux in the magnetic material, and the magnetic flux can be prevented from leaking to the outside. Therefore, the reader / writer and the IC card can communicate with each other by passing the magnetic flux through the loop coil of the IC card.
According to a second aspect of the present invention, the magnetic flux introduction means includes a gap portion through which at least the IC card can be inserted in a loop-shaped magnetic path that guides the magnetic flux generated by the loop coil, and the IC card is inserted into the gap portion. Thus, the loop antenna provided in the IC card is configured such that the magnetic flux propagating through the gap portion traverses.
In order to efficiently take the magnetic flux flowing in the magnetic material into the IC card, a part of the magnetic material is cut to form a gap, and the IC card loop antenna is inserted into the gap, and the magnetic flux crosses through the gap. If it does in this way, the change of magnetic flux can be converted into an electromotive force with a loop antenna.
According to a third aspect of the present invention, the gap portion is configured to cover at least a part of a loop antenna provided in an IC card inserted through the gap portion.
Magnetic flux is radiated from the surface area of the end of the gap, so if the surface area is small, the magnetic flux density increases. However, since the loop antenna of the IC card has a certain surface area, the distance between the loop antenna and the magnetic flux is small. The possibility of leaving increases. As a result, the electromotive force generated in the loop antenna is lowered. Therefore, the present invention is configured to cover at least a part of the loop antenna so that the magnetic flux passes through the surface area of the loop antenna as uniformly as possible.

A fourth aspect of the present invention is characterized in that the magnetic flux introducing means is made of ferrite or a material having a small magnetic resistance.
The magnetic flux introducing means is made of a magnetic material. As the magnetic material, ferrite obtained by sintering magnetic powder having a large coercive force is preferable. Further, if the magnetic resistance of the magnetic path is high, the magnetic flux is consumed as heat, and the magnetic flux supplied to the IC card is reduced. Therefore, a material having a small magnetic resistance is preferable as the magnetic material.
According to a fifth aspect of the present invention, a first magnetic field shielding unit is provided between a loop coil side wound around a loop-shaped magnetic path of the magnetic flux introducing unit and the gap portion.
When the material of the magnetic flux introducing means is ferrite, the magnetic flux flows almost without leaking to the outside because the magnetic permeability is larger than in air. However, electromagnetic waves leak to the outside from the loop coil portion and the reader / writer. Therefore, in the present invention, first magnetic field shielding means for shielding electromagnetic waves leaking from the loop coil and the reader / writer is provided between the loop coil and the gap portion.
According to a sixth aspect of the present invention, the first magnetic field shielding means and the second magnetic field shielding means for covering all of the loop coil, the magnetic flux introducing means, and the reader / writer are provided at the same time.
Even if the first magnetic field shielding means is provided between the loop coil and the gap, it cannot be completely shielded. In addition, there is a leakage magnetic field from the magnetic flux introduction means and the gap. Also, electromagnetic waves due to high frequency leak from the reader / writer. Therefore, in the present invention, in order to reliably block these leakage electromagnetic fields, in addition to the first magnetic field shielding means, a second magnetic field shielding means for covering all of the loop coil, the magnetic flux introducing means, and the reader / writer is provided. It is.

According to a seventh aspect of the present invention, there is further provided correction means for correcting a deviation of a resonance frequency from the IC card inserted through the gap portion in the vicinity of the gap portion provided in the magnetic flux introducing means.
When a loop coil is wound around a magnetic material and communication with an IC card is performed, the frequency transmitted from the original loop coil may be slightly shifted. As a result, the resonance frequency with the IC card shifts, and it is necessary to correct the shift. In view of this, the present invention further includes correction means for correcting the shift of the resonance frequency in the vicinity of the gap portion in order to correct the shift.
According to an eighth aspect of the present invention, the correction means is a coil or a metal plate having an inductance sufficient to correct a shift in resonance frequency with the IC card.
The resonance circuit of the reader / writer is a parallel resonance circuit composed of an inductor and a capacitor. Therefore, in order to correct the value of the inductor as correcting means, a coil having a predetermined mutual inductance is arranged.
A ninth aspect of the present invention is characterized in that the first magnetic field shielding means and the second magnetic field shielding means are made of a conductor.
Generally, the frequency used for the IC card is a 13.56 MHz short wave. Therefore, the coupling between the magnetic flux introducing means and the loop antenna is mainly a magnetic field coupling using an electromagnetic wave having both a magnetic field component and an electric field component. However, the reader / writer is equipped with a CPU that controls the entire apparatus, a high-frequency oscillator that supplies a high-frequency current to the loop coil, and the like. Therefore, this part emits digital noise. The high frequency component of this digital noise extends from the VHF band to the UHF band. Further, since the IC card is maintained in an earthless state, the high frequency component is mainly an electromagnetic wave component having both a magnetic field component and an electric field component. The electromagnetic wave component can be attenuated by attenuating either the magnetic field component or the electric field component. Therefore, in the present invention, since the electric field component does not easily pass through the conductor, it is shielded by a metal plate.

According to the first aspect of the present invention, the magnetic flux introducing means has a configuration capable of supplying a magnetic flux enabling at least communication with the IC card to the loop antenna provided in the IC card. The magnetic flux generated by the generated magnetic field can be efficiently supplied to the IC card.
According to the second aspect of the present invention, a gap is formed by cutting a part of the magnetic material, and the loop antenna of the IC card is inserted into the gap so that the magnetic flux passes therethrough. It can be passed through the loop antenna.
According to the third aspect of the present invention, since the gap is formed so as to cover at least a part of the loop antenna, the magnetic flux can pass through the surface area of the loop antenna as uniformly as possible.
According to a fourth aspect of the present invention, since the magnetic flux introducing means is made of ferrite or a material having a small magnetic resistance, the leakage magnetic field can be reduced and the magnetic flux can be passed through the loop antenna efficiently.
According to the fifth aspect of the present invention, since the first magnetic field shielding means is provided between the loop coil and the gap, electromagnetic waves leaking from the loop coil and the reader / writer can be shielded to some extent.
According to the sixth aspect of the invention, in addition to the first magnetic field shielding means, the second magnetic field shielding means that covers all of the loop coil, the magnetic flux introducing means, and the reader / writer main body is provided, so that the electromagnetic wave having both the magnetic field component and the electric field component. Ingredients can be reliably blocked.
According to the seventh aspect of the present invention, since the correction means for correcting the shift of the resonance frequency is further provided in the vicinity of the gap, the resonance frequency of the reader / writer and the IC card can be matched.
According to the eighth aspect of the present invention, since a coil having a predetermined mutual inductance is arranged as the correcting means, the installation becomes easy and the distance of the gap portion can be reduced.
According to a ninth aspect of the present invention, since the first magnetic field shielding means and the second magnetic field shielding means are made of metal, the electric field component can be blocked from being transmitted through the conductor.

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. However, the components, types, combinations, shapes, relative arrangements, and the like described in this embodiment are merely illustrative examples and not intended to limit the scope of the present invention only unless otherwise specified. .
FIG. 1 is a block diagram showing a configuration of a general IC card reader / writer control unit. The IC card reader / writer control unit (hereinafter simply referred to as a reader / writer control unit) 100 is controlled by a PC 50 that exchanges data with the reader / writer control unit 100 to control the entire system. The reader / writer control unit 100 includes a transmission / reception device 1 that controls a data communication protocol with an external PC 50, a control device 2 that controls the operation of the entire reader / writer control unit 100, and firmware that records a procedure for operating the control device 2. The memory device 3 for storing the read data, the modulator 4 for modulating the data from the control device 2 on a carrier wave, the input device 5 for inputting an operation command, and the information controlled by the control device 2 are displayed. Display device 6, power supply signal that is an AC signal from control device 2, power amplifier 7 that amplifies the write command from modulator 4, and conversion from a carrier wave received from loop coil 9 to binary data Detecting demodulator 8, loop coil 9 for exchanging power and data with an IC card (not shown), and a magnetic flux introducing unit 11 to be described later. It is configured with a 120, 130, 140.
Next, before describing the operation of the reader / writer control unit 100 according to this configuration, the configuration of the IC card will be described first. FIG. 2 is a block diagram showing the configuration of the IC card. The IC card 200 of this embodiment includes a loop antenna 20 that transmits and receives data using a power carrier wave from the reader / writer control unit 100, a transmission / reception circuit 21 that generates a write command read command, and a power carrier wave from the loop antenna 20. Power generation circuit 22 that rectifies and converts it into DC power, a memory device 23 that manages storage of control firmware and data, and a modulator 24 that modulates a transmission command from the control circuit 26 with a carrier wave. And a detector 25 for converting the carrier wave data from the transmission / reception circuit 21 into binarized data, and a control circuit 26 for controlling the overall operation of the IC card 200.

Next, each operation will be described with reference to FIGS. 1 and 2 together. The reader / writer control unit 100 starts an operation according to a program stored in the memory device 3 after the initial operation of the control device 2 when a power supply (not shown) is turned on. First, initialization is performed. Next, the control device 2 alternately transmits a power supply signal supplied to the IC card 200 and a polling signal obtained by modulating the power supply signal from the power amplifier 7. The signal is supplied as a magnetic flux from the loop coil 9 to the magnetic flux introduction units 110, 120, 130, and 140. Next, when the IC card 200 is inserted into the magnetic flux introduction units 110, 120, 130, and 140, the loop antenna 20 receives the power supply signal, and the power generation circuit 22 rectifies the carrier wave to convert it into DC power. , And supplied to all circuits in the IC card 200. When power is supplied and the control circuit 26 is driven, control is started in accordance with a program stored in the memory device 23.
Next, the control circuit 26 first demodulates the command from the transmission / reception circuit 21 by the detector 25 and converts it into a binary signal, and analyzes the command. As a result, when it is recognized that it is called, the response is modulated by the modulator 24 and transmitted from the loop antenna 20 via the transmission / reception circuit 21. The reader / writer control unit 100 receives this response with the loop coil 9, converts it into a binary code with the detector demodulator 8, analyzes it with the control circuit 2, and the IC card 200 is an IC card that conforms to the standard. recognize.

FIG. 3A is a diagram showing the configuration of the reader / writer according to the first embodiment of the present invention. The same components will be described with the same reference numerals. The reader / writer 110 includes a reader / writer control unit 100 that transmits and receives carrier power based on a predetermined modulation / demodulation method with the IC card 200 via the loop antenna 20 included in the IC card 200, and an IC. A loop coil 9 that mediates propagation of a power carrier wave to the card 200 and data transmission / reception with the IC card 200, and a loop coil 9 is wound around at least a part to guide a magnetic field generated from the loop coil 9 as a magnetic flux 13. And a ferrite core (magnetic flux introducing means) 14. The ferrite core 14 includes a gap portion 15 into which at least the IC card 200 can be inserted in a loop-shaped magnetic path that guides the magnetic flux 13 generated by the loop coil 9, and the IC card 200 is inserted into the gap portion 15. As a result, the magnetic flux 17 propagating through the gap 15 crosses the loop antenna 20 provided in the IC card 200. The gap 15 is configured to cover at least a part of the loop antenna 20 provided in the IC card 200 inserted through the gap 15. In the present embodiment, the ferrite core 14 is used as a means for guiding the magnetic field generated from the loop coil 9 as the magnetic flux 13, but other materials may be used as long as the material has a low magnetic resistance.
FIG. 3B is an equivalent circuit of FIG. For example, the length of the magnetic path excluding the gap 15 of the ferrite core 14 is l ₁ , the cross-sectional area is S, the magnetic permeability is μ, the gap length of the gap 15 is l ₂ , the cross-sectional area is S ₀ , The magnetic susceptibility is μ ₀ . When a signal of voltage V is generated from the reader / writer 100 and the current I flows through the loop coil 9 having N turns, the magnetomotive force = N · I and the magnetic resistance R ₁ of the magnetic path excluding the gap 15 = l ₁ / μ · S, and the magnetic resistance R ₂ of the gap 15 is equal to l ₂ / μ ₀ · S ₀ . Accordingly, the magnetic flux of the ferrite core 14 becomes φ ₀ = N · I / R ₁ · R ₂ , and it can be seen that the magnetic flux φ ₀ is efficiently supplied to the IC card 200 as the magnetic resistance is reduced. That is, since the magnetic resistance is proportional to the lengths l _{1 and} l ₂ of the magnetic path, it is necessary to reduce the size of the ferrite core and narrow the gap 15 as much as possible.

FIG. 4A is a diagram showing the configuration of the reader / writer according to the second embodiment of the present invention. The same components will be described with the same reference numerals. This reader / writer 120 is a correction coil (correction means) 18 that corrects a deviation in resonance frequency with the IC card 200 inserted through the gap 15 in the vicinity of the gap 15 provided in the ferrite core 14 (upper part in this figure). Is further provided. That is, when the loop coil 9 is wound around the ferrite core 14 to communicate with the IC card 200, the resonance frequency of the loop antenna 20 of the IC card 200 may be slightly shifted. It is necessary to correct the deviation. Therefore, in the present embodiment, a correction coil 18 or a metal plate for correcting the shift of the resonance frequency is further provided in the vicinity of the gap portion 15 in order to correct the shift.
FIG. 4B is an equivalent circuit of the gap 15 portion. The resonance circuit of the reader / writer 100 is a parallel resonance circuit composed of an inductor L ₁ and a capacitor C. Therefore, in order to correct the value of the inductor as correcting means, a metal plate that reduces the coil ΔL or L having a predetermined mutual inductance M is arranged. In the present embodiment, the correction coil 18 for correction is disposed above the gap portion 15, but it may be disposed on the lower side.
FIG. 5 is a diagram showing the configuration of a reader / writer according to the third embodiment of the present invention. The same components will be described with the same reference numerals. The reader / writer 130 includes a metal plate (first magnetic field shielding means) between the gap 15 and the loop coil 9 side (side including the reader / writer control unit 100) wound around the loop-shaped magnetic path of the ferrite core 14. ) 19. That is, when the material of the means for introducing the magnetic flux is ferrite, the magnetic flux 13 flows almost without leaking to the outside because the magnetic permeability is larger than in the air. However, electromagnetic waves leak from the loop coil 9 and the reader / writer control unit 100 to the outside. Therefore, in the present embodiment, a metal plate 19 that shields electromagnetic waves leaking from the loop coil 9 and the reader / writer control unit 100 is provided between the loop coil 9 and the gap 15. Thereby, a part of electromagnetic waves radiated | emitted from the loop coil 9 and the reader / writer control part 100 are absorbed by the metal plate 19, and can reduce unnecessary radiation noise. In the present embodiment, the metal plate 19 is used as the magnetic field shielding means. However, the metal plate 19 need not be limited to a metal as long as it is a conductor.

FIG. 6 is a diagram showing a configuration of a reader / writer according to the fourth embodiment of the present invention. The same components will be described with the same reference numerals. The reader / writer 140 includes a metal plate 19 and a metal case (second magnetic field shielding means) 31 that covers all of the loop coil 9, the ferrite core 14, and the reader / writer control unit 100 at the same time. Further, the metal shutter 30 may be provided in the opening into which the IC card 200 is inserted. In this embodiment, the metal plate 19, the metal shutter 30, and the metal case 31 are used as the magnetic field shielding means. However, the conductor is not limited to metal as long as it is a conductor.
Generally, the frequency used for the IC card 200 is a short wave of 13.56 MHz. Therefore, the coupling between the ferrite core 14 and the loop antenna 20 of the IC card 200 is mainly a magnetic field coupling using an electromagnetic wave having both a magnetic field component and an electric field component. However, the reader / writer control unit 100 is equipped with a CPU that controls the entire apparatus, a high-frequency oscillator that supplies a high-frequency current to the loop coil 9, and the like. Therefore, this part emits digital noise. The high frequency component of this digital noise extends from the VHF band to the UHF band. Further, since the IC card 200 is maintained in an earthless state, the high frequency component is mainly an electromagnetic wave component having both a magnetic field component and an electric field component. The electromagnetic wave component can be attenuated by attenuating either the magnetic field component or the electric field component. Therefore, in the present embodiment, since the electric field component is difficult to transmit through the conductor, it is shielded with a metal plate.
That is, even if the metal plate 19 is provided between the loop coil 9 and the gap 15, the electromagnetic wave cannot be completely shielded. In addition, there is a considerable leakage magnetic field from the ferrite core 14 and the gap 15. Further, the reader / writer control unit 100 leaks electromagnetic waves due to high frequencies. Therefore, in the present embodiment, in order to reliably block these leakage electromagnetic fields, a metal case 31 that covers all of the loop coil 9, the ferrite core 14, and the reader / writer control unit 100 is provided in addition to the metal plate 19. is there.

As described above, according to the present invention, the ferrite core 14 has a configuration capable of supplying a magnetic flux enabling at least communication with the IC card 200 to the loop antenna 20 provided in the IC card 200. The leakage magnetic field can be reduced, and the magnetic flux generated by the generated magnetic field can be efficiently supplied to the IC card 200.
Further, a part of the ferrite core 14 is cut to form the gap 15, and the loop antenna 20 of the IC card 200 is inserted into the gap 15 so that the magnetic flux passes through the gap 15. It can be passed through the loop antenna 20 well.
In addition, since the gap 15 is configured to cover at least a part of the loop antenna 20, the magnetic flux can be passed through the surface area of the loop antenna 20 as uniformly as possible.
Further, since the means for introducing the magnetic flux is made of ferrite or a material having a small magnetic resistance, the leakage magnetic field can be reduced and the magnetic flux can be passed through the loop antenna 20 efficiently.
Further, since the metal plate 19 is provided between the loop coil 9 and the gap portion 15, electromagnetic waves leaking from the loop coil 9 and the reader / writer control unit 100 can be shielded to some extent.
In addition to the metal plate 19, the metal case 31 that covers all of the loop coil 9, the ferrite core 14, and the reader / writer control unit 100 is provided, so that the electromagnetic wave component having both the magnetic field component and the electric field component can be reliably blocked. Can do.
Further, since the correction coil 18 or the metal plate for correcting the shift of the resonance frequency is further provided in the vicinity of the gap portion 15, the resonance frequency of the reader / writer control unit 100 and the IC card 200 can be matched.
Further, since the correction coil 18 having a predetermined mutual inductance is arranged as the correction means, the installation becomes easy and the distance of the gap 15 can be reduced.
Further, since the metal plate 19 and the metal case 31 are made of metal, it is possible to block the electric field component from passing through the conductor.

It is a block diagram which shows the structure of the general reader / writer for IC cards. It is a block diagram which shows the structure of an IC card. (A) is a figure which shows the structure of the reader / writer based on the 1st Embodiment of this invention, (b) is an equivalent circuit schematic of (a). (A) is a figure which shows the structure of the reader / writer based on the 2nd Embodiment of this invention, (b) is an equivalent circuit schematic of the gap | interval part 15 part. It is a figure which shows the structure of the reader / writer which concerns on the 3rd Embodiment of this invention. It is a figure which shows the structure of the reader / writer which concerns on the 4th Embodiment of this invention.

Explanation of symbols

  9 loop coil, 13 magnetic flux, 14 ferrite core, 15 gap, 20 loop antenna, 100 reader / writer control unit, 110 reader / writer, 200 IC card

Claims (9)

In an IC card reader / writer that transmits and receives carrier power based on a predetermined modulation / demodulation method with the IC card via a loop antenna provided in the IC card,
A loop coil that mediates propagation of a power carrier wave to the IC card and exchange of data with the IC card, and a magnetic flux introducing means that guides the magnetic field generated from the loop coil by winding the loop coil at least at a part thereof The IC card reader / writer is characterized in that the magnetic flux introducing means can supply a magnetic flux enabling at least communication with the IC card to the loop antenna on the IC card side. .   The magnetic flux introducing means includes a gap portion through which at least the IC card can be inserted in a loop-shaped magnetic path that guides the magnetic flux generated by the loop coil, and by inserting the IC card into the gap portion, 2. The IC card reader / writer according to claim 1, wherein a loop antenna provided in the IC card is configured such that a magnetic flux propagating through the gap portion crosses the loop antenna.   3. The IC card reader / writer according to claim 1, wherein the gap portion is configured to cover at least a part of a loop antenna provided in an IC card inserted through the gap portion.   3. The IC card reader / writer according to claim 1, wherein the magnetic flux introducing means is made of ferrite or a material having a small magnetic resistance.   The first magnetic field shielding means is provided between the loop coil side wound around the loop-shaped magnetic path of the magnetic flux introducing means and the gap portion, according to any one of claims 1 to 4. The IC card reader / writer as described.   The first magnetic field shielding means and the second magnetic field shielding means for covering all of the loop coil, the magnetic flux introducing means, and the reader / writer are provided at the same time. The IC card reader / writer as described in 1.   7. A correction means for correcting a deviation in resonance frequency with an IC card inserted through the gap portion in the vicinity of the gap portion provided in the magnetic flux introduction means. The reader / writer for IC cards according to claim 1.   8. The IC card reader / writer according to claim 7, wherein the correction means is a coil or a metal plate having an inductance sufficient to correct a shift in resonance frequency with the IC card.   7. The IC card reader / writer according to claim 5, wherein the first magnetic field shielding means and the second magnetic field shielding means are made of a conductor.

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