JPH11213108A - Reader/writer for no-contact ic card - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-contact IC card reader/writer provided with a reading/writing antenna capable of reducing influence to the outside and forming a stable communication area matched with a purpose. SOLUTION: Radio communication is executed between a non-contact IC card and the reader/writer through an antenna 40. A main antenna 41 is a rectangular loop-like communication antenna. Plural rectangular loop-like sub- antennas 42 to 45 are arranged around the main antenna 41 so as to surround the main antenna 41 by matching one side of each sub-antenna with each side of the main antenna 41. These sub-antennas 42 to 45 are an antenna group for uniformly collecting generated magnetic flux to the main antenna 41. The main antenna 41 and the sub-antennas 42 to 45 are mutually connected like a character written by one stroke and the direction of a current flowing through the loop of each sub-antenna is made reverse to that of a current flowing through the loop of the main antenna 41.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a read / write device for a contactless IC card which is applied to an automatic ticket collection machine at a station and communicates wirelessly with a contactless IC (integrated circuit) card. The present invention relates to a structure of a read / write antenna provided in the device for communication with a contact IC card.

[0002]

2. Description of the Related Art In recent years, as the development of non-contact IC cards has progressed, they have been put to practical use in various applications such as automatic ticket collection machines at stations, and in the future, will be frequently used in place of other types of cards. It is expected that Therefore, the hardware configuration and operation of the non-contact IC card and the read / write device for reading and writing data from and to the non-contact IC card will be outlined below. FIG. 1 is a block diagram showing an electrical configuration of a non-contact IC card and a read / write device. In the figure, reference numeral 1 denotes a read / write device, and reference numeral 20 denotes a non-contact IC card. In each case, only the main components related to the present invention are shown.

First, the configuration of the read / write device 1 will be described. A CPU (Central Processing Unit) 2 performs various processing controls on each unit in the read / write device 1 described below. ROM (read only memory) 3 is CPU 2
Control program to be executed by
An M (random access memory) 4 stores data necessary for processing performed by the CPU 2 and temporarily stores data exchanged with the non-contact IC card 20. Communication interface (hereinafter abbreviated as “communication I / F”) circuit 5
Is an interface circuit for performing communication with a control host computer (not shown) provided outside the read / write device 1. The communication I / F circuit 6 is the same type of interface circuit as the communication I / F circuit 5,
It controls communication between the CPU 2 and a modulator 8 and a demodulator 12 described later.

[0004] An oscillator 7 generates a synchronization signal of a predetermined frequency. The modulator 8 modulates a synchronization signal supplied from the oscillator 7 with data supplied from the CPU 2 via the communication I / F circuit 6. The driver 9 power-amplifies the output signal of the modulator 8, and the read / write antenna 10 emits the output of the driver 9 to the outside of the read / write device 1 as an electromagnetic wave. The filter 11 removes unnecessary frequency components from the electromagnetic wave received by the antenna 10 to remove noise and the like. The demodulator 12 performs demodulation processing on the output signal of the filter 11 and sends out the demodulated signal to the CPU 2 via the communication I / F circuit 6.

Next, the configuration of the internal circuit of the non-contact IC card 20 will be described. The receiving antenna 21 is the antenna 1
It receives an electromagnetic wave radiated from 0 and outputs an AC signal. The power supply 22 supplies a DC voltage to each part in the non-contact IC card 20 by rectifying an AC signal obtained from the receiving antenna 21. Thus, the provision of the power supply 22 allows the non-contact IC card 20 to operate without a power source. Note that a power supply line between the power supply unit 22 and each unit in the non-contact IC card is omitted from the figure for the sake of simplicity.

The clock generator 23 extracts a synchronizing clock from the AC signal supplied from the receiving antenna 21 and distributes it to each unit in the non-contact IC card 20. The wiring between the clock generator 23 and each unit is not shown. The demodulator 24 demodulates the AC signal supplied by the receiving antenna 21. The memory 25 is a rewritable nonvolatile memory, and stores data necessary for processing of the contactless IC card. The I / O (input / output) control circuit 26 controls writing of data to the memory 25 according to the output signal of the demodulator 24, reads data from the memory 25, and supplies the data to the modulator 27. The modulator 27 outputs an AC signal obtained by modulating the data from the I / O control circuit 26 to the transmission antenna 28, and the transmission antenna 28 emits this as electromagnetic waves to the outside of the non-contact IC card 20.

FIG. 2 is a perspective view showing the shape of the antenna 10. The antenna 10 includes an air-core coil 30 wound with a copper wire, and lead wires 31 and 32 for passing a current through the air-core coil 30, and is formed as a rectangular loop in the illustrated example. . The antenna 10 communicates with the reception antenna 21 and the transmission antenna 28 using electromagnetic induction caused by a magnetic flux generated by flowing an alternating current through the air-core coil 30. The arrow attached to the air core coil 30 indicates the direction in which current flows.

On the other hand, FIG. 3 shows the antenna 1 when viewed from the side of the antenna 10 in the direction of AA 'in FIG.
FIG. 4 is a diagram showing a state of a magnetic flux generated from zero. As described above, since the antenna 10 is constituted by a single air-core loop coil, a uniform magnetic flux is generated in the air as shown in FIG. In FIG. 3, the lead wires 31, 3
2 is not shown.

According to the above configuration, the modulator 8 modulates the data of the CPU 2 sent from the communication I / F circuit 6 with the output signal of the oscillator 7, amplifies the power with the driver 9, and amplifies the power of the antenna 1.
It operates to input an alternating current to 0. As a result, a magnetic flux is generated from the antenna 10 as shown in FIG. Then, since the induced power is generated in the non-contact IC card 20 on the receiving side by the electromagnetic induction, power can be supplied from the read / write device 1 to the non-contact IC card 20.

The operation relating to the transfer of data between the read / write device 1 and the non-contact IC card 20 is not directly related to the present invention, and therefore the description thereof is omitted. On the other hand,
FIG. 4 is a perspective view showing an overview of devices when the read / write device 1 is applied to an automatic ticket collection machine 50 at a station. In the figure, a communication area CA1 is a non-contact IC card 20.
(Not shown) shows a space in which communication is possible. As shown in the figure, it can be seen that the communication area CA1 is substantially spherical and extends in all directions with the antenna 10 as a center.

[0011]

As described above, the antenna 10 having the shape shown in FIG.
In the case of using, the following problems arise. (1) Since electromagnetic induction by a single air-core loop coil is used, a magnetic field is uniformly generated in air as shown in FIG. Therefore, the communication area is fixed,
A communication area that meets the purpose cannot be formed. (2) When electromagnetic induction is used, the induced power generated on the receiving side is proportional to the magnetic flux passing through the coil of the receiving side antenna. Therefore, for example, when the output power from the coil of the antenna 10 is increased, the effect is correspondingly increased. The area is widened and interferes with peripheral devices other than the non-contact IC card. (3) Due to such restrictions on the output power, unless the antenna is enlarged, the stability of communication with the non-contact IC card cannot be improved.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object to provide a non-contact non-contact antenna having a read / write antenna capable of forming a stable communication area with little influence on the outside. An object of the present invention is to provide a read / write device for an IC card.

[0013]

According to a first aspect of the present invention, there is provided a non-contact IC card for performing wireless communication with a non-contact IC card using a read / write antenna. A read / write device, wherein the read / write antenna comprises a communication loop-shaped main antenna, and a loop arranged around the main antenna and in which a current flows in a direction opposite to a current flowing through the main antenna. And a sub-antenna having: According to a second aspect of the present invention, in the first aspect of the present invention, the main antenna and the sub-antenna are connected in a one-stroke form. The invention according to claim 3 is the invention according to claim 1 or 2, wherein the main antenna and the sub-antenna are formed in a rectangular shape, and each side of the main antenna and one side of the sub-antenna are brought close to each other. The main antenna is surrounded by the sub-antenna.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. The configuration of the read / write device and the non-contact IC card in this embodiment is basically the same as that shown in FIG. 1, and the structure of the read / write antenna provided in the read / write device 1 is shown in FIG. Is different.

FIG. 5A is a perspective view showing the shape of the read / write antenna 40 according to the present embodiment. In the figure, reference numeral 41 denotes a main antenna for communication, which is shown in FIG.
Has a rectangular loop shape like the antenna 10 shown in FIG. Around this main antenna 41, rectangular loop-shaped sub-antennas 42 to 45 are provided. These sub-antennas 42 to 45 are an antenna group for collecting uniformly generated magnetic flux on the main antenna 41 as shown in FIG. In addition, these sub-antennas are arranged so as to surround the main antenna 41.

However, as can be seen from FIG.
Actually, the main antenna 41 and the sub antennas 42 to 45
Are not independent, and the main antenna 41 and the sub-antennas 42 to 45 are connected such that a single stroke is drawn from the entrance to the exit of the antenna 40 (that is, between the lead wire 31 and the lead wire 32). FIG. 5B is a plan view of the portion of the antenna 40 in which only the left side of the main antenna 41 and the sub antenna 42 are enlarged. As shown in the figure, the direction of the current flowing through the loop of the sub-antenna 42 and the direction of the current flowing through the loop of the main antenna 41 are reversed. The former is clockwise, while the latter is counterclockwise. . This is the same for the other sub-antennas 43 to 45.

With the above antenna shape,
The magnetic flux generated from the antenna 40 is as shown in FIG. In FIG. 5, the cross section is viewed from the side of the antenna 40 in the direction of BB ′ in FIG. As can be seen from FIG. 6, in the present embodiment, unlike the above-described prior art, the generated magnetic flux is not uniform. That is, in the prior art, the magnetic flux diverges uniformly to the outside, whereas in the present embodiment, the sub-antennas 42 to 45
As a result, the magnetic flux generated from the main antenna 41 is drawn into the sub-antenna side, and an ear-shaped magnetic flux as shown is generated.

By adjusting the size of the main antenna 41 and the sub-antennas 42 to 45 and the number of turns of the air-core coils constituting these antennas, the magnetic flux of the main antenna 41 is pulled in when it is drawn into the sub-antenna. Since the condition can be adjusted, the communication area can be freely formed according to the purpose.

Also, instead of the antenna 10, the antenna 4
When the read / write device using the “0” is applied to the automatic ticket collection machine 50 at the station, the communication area between the read / write device 1 and the non-contact IC card 20 is the communication area CA shown in FIG.
It looks like 2. That is, the communication area C shown in FIG.
The shape is disc-shaped compared to A1, and the space covered by the communication area CA2 extends further upward than the communication area CA1. As a result, the magnetic flux density on the main antenna 41 increases,
More electric power can be supplied to the C card (not shown). In addition, the magnetic flux generated from the main antenna 41 is drawn into the sub-antenna side,
Since the amount of divergence of the magnetic flux to the distant place is reduced and the electromagnetic wave is reduced, the output current flowing to the antenna can be increased as a result.

[0020]

As described above, according to the present invention, the following effects can be obtained. (1) By adjusting the size of the main antenna and the sub-antenna and the number of turns of the coil forming these antennas, the degree of retraction when the magnetic flux generated by the main antenna is drawn into the sub-antenna can be adjusted. An appropriate communication area can be formed. (2) Since the magnetic flux generated from the read / write antenna is not uniform, the influence on the outside can be reduced. (3) Since the magnetic flux density on the main antenna can be increased, communication with the non-contact IC card can be further stabilized. (4) Since the magnetic flux diverging to a distant place is suppressed, the current flowing to the antenna can be increased, which contributes to the improvement of communication stability and can extend the communication distance. (5) Since only the shape of the coil forming each antenna needs to be changed, other extra materials are not required.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an electrical configuration of a non-contact IC card communication device including a non-contact IC card and a read / write device.

FIG. 2 is a perspective view showing the shape of a conventional read / write antenna 10;

FIG. 3 is an explanatory diagram showing a state of a magnetic flux generated from the antenna 10.

FIG. 4 shows an overview of a device when the read / write device 1 having the antenna 10 is applied to an automatic ticket collection machine 50 at a station and a communication area CA1 between the non-contact IC card and the read / write device 1. It is a perspective view.

FIG. 5A is a perspective view showing the shape of a read / write antenna 40 according to an embodiment of the present invention,
(B) shows the main antenna 41 in the antenna 40.
FIG. 5 is a plan view showing only the vicinity of the left side of FIG.

FIG. 6 is an explanatory diagram showing a state of a magnetic flux generated from the antenna 40.

FIG. 7 shows an overview of a device when the read / write device 1 having the antenna 40 is applied to an automatic ticket collection machine 50 at a station, and shows a communication area CA2 between the non-contact IC card and the read / write device 1. It is a perspective view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Read / write device 20 Non-contact IC card 40 Antenna 41 Main antenna 42-45 Sub-antenna 50 Station automatic ticket collection machine CA2 Communication area

Claims (3)

[Claims] 1. A non-contact IC card read / write device for performing wireless communication with a non-contact IC card using a read / write antenna, wherein the read / write antenna has a communication loop shape. A read / write device for a non-contact IC card, comprising: a main antenna; and a sub-antenna arranged around the main antenna and having a loop in which a current flowing in a direction opposite to a current flowing through the main antenna flows. . 2. The non-contact IC card read / write device according to claim 1, wherein the main antenna and the sub-antenna are connected in a one-stroke form. 3. The main antenna and the sub-antenna are formed in a rectangular shape, each side of the main antenna and one side of the sub-antenna are brought close to each other, and the main antenna is surrounded by the sub-antenna. The read / write device for a non-contact IC card according to claim 1 or 2.