JP2000216715A - Communication system utilizing noncontact information medium and communication auxiliary equipment used for such communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve reliability and to extend the possible distance for communication by utilizing a reader-writer carrier to generate a carrier of a different frequency, using data from a noncontact information medium for transmission and providing auxiliary equipment to relay the data from the medium to a reader-writer. SOLUTION: A noncontact IC card 10 receives radio waves fc from the reader-writer of an external device, a power circuit 102 generates operation power VDD through electromagnetic induction, and a frequency divider 122 makes the fc tune into a clock from a timing circuit 112 to generate a subcarrier fs of a prescribed frequency. A modulator 114 modulates the fc with the fs under the control of a control circuit 106 and transmits it to the reader- writer. In this a case, communication auxiliary equipment having a resonance circuit consisting of an antenna coil and a capacitor is arranged between the card 10 and while making the antenna coil coincide with the normal line direction of the antenna coil of the reader-writer, the radio waves of the card 10 are increased, relayed and transferred to the reader-writer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to a communication system, and more particularly, to a data communication system using a contactless information medium. "Non-contact information medium" means IC
A medium that includes an information recording module such as a chip and communicates with an external device such as a reader / writer without contact. Therefore, as long as it is non-contact, the wavelength of the radio wave does not matter, and the length of the communication distance does not matter.

A typical non-contact information medium is, for example, a non-contact IC card that communicates with a reader / writer using microwaves. In this application, “IC
"Card" covers smart cards, intelligent cards, chip-in cards, microcircuit (microcomputer) cards, memory cards, super cards, multi-function cards, and combination cards.

[0003] The shape of the non-contact information medium is not limited to a card. Therefore, it is the so-called I
Also includes C tag. Here, the “IC tag” has the same function as the IC card, but includes all information recording media having a stamp size, a micro size smaller than that, a coin shape, and the like.

[0004]

2. Description of the Related Art As is well known, IC cards can be classified into contact type and non-contact type according to a communication method between an IC chip built in the card and a reader / writer.
Among them, the non-contact type has no contact with the reader / writer, so there is no contact failure, and several centimeters to several tens c from the reader / writer.
It can be used at a distance of m, and is resistant to dirt, rain, and static electricity. Its demand is expected to increase in the future.

A non-contact IC card obtains operating power by electromagnetic induction using electromagnetic waves of a carrier frequency received from a reader / writer, and modulates the carrier frequency according to transmitted information to exchange data with the reader / writer. Exchange. The non-contact IC card and the reader / writer usually have built-in antennas for transmitting and receiving such radio waves.

[0006]

However, the carrier frequency is a source of operating power, and the communication from the non-contact IC card to the reader / writer uses a different frequency that does not interfere with the carrier frequency. Can be improved,
Further, it is considered that the operation power can be saved. On the other hand, when modulation is applied to a frequency other than the carrier frequency, the degree of modulation is small, so that there is a problem that the communication distance becomes short.

Further, in order for a conventional non-contact IC card to perform wireless communication with a reader / writer, an antenna (for example, an antenna coil) of the non-contact IC card is parallel to an antenna (for example, an antenna coil) of the reader / writer. It had to be placed directly above it. For example, non-contact IC
Even if the card is directly above the reader / writer, if the antenna coil of the non-contact IC card is inclined with respect to the normal direction of the antenna coil of the reader / writer, the communication distance will be caused by the directivity of the antenna according to the inclination angle. Communication becomes impossible if the normal directions of both antenna coils are orthogonal to each other.

Further, if the non-contact IC card is separated from right above the antenna of the reader / writer, the two cannot communicate with each other due to the directivity of the antenna. As a result, the communicable area is limited to a certain area just above the antenna of the reader / writer. I was

As described above, in the conventional communication between the non-contact IC card and the reader / writer, there are restrictions on the tilt angle based on the directivity of the antenna, restrictions on the communicable area, and restrictions on the communication distance. Since the communicable area is invisible, operability is poor for the user of the non-contact IC card, and quick reading cannot be achieved.

[0010]

SUMMARY OF THE INVENTION It is a general object of the present invention to provide a new and useful communication system which solves such conventional problems, and a communication auxiliary device used in such a communication system. .

More specifically, the present invention provides a communication system capable of extending the communication distance while ensuring the same or higher communication reliability as before, and a communication auxiliary device used in such a communication system. The purpose is to do.

It is another object of the present invention to provide a communication system capable of achieving lower power consumption than before and a communication auxiliary device used for such a communication system.

[0013] The present invention also provides a constraint on an inclination angle based on the directivity of an antenna between a non-contact information medium and an external device.
It is another object of the present invention to provide a communication system for easily and inexpensively reducing the restrictions on the communication area and the communication distance, and a communication auxiliary device used for such a communication system.

[0014] In order to achieve the above object, a communication system according to a first aspect of the present invention comprises a non-contact information medium and the non-contact information medium using a carrier having a first frequency as a carrier frequency. An external device capable of communication, and a second frequency different from the first frequency generated using the first frequency, which can be enhanced, and a communication electromagnetically coupled to the external device. And an auxiliary device.

Further, the communication system according to the second aspect of the present invention can communicate with the non-contact information medium using a non-contact information medium and a carrier having a first frequency as a carrier frequency. An external device, the first frequency can be enhanced, a first communication auxiliary device electromagnetically coupled to the external device, and the second frequency can be enhanced, and an electromagnetic coupling to the external device can be enhanced. A second communication auxiliary device.

Further, the communication auxiliary device of the present invention comprises:
When the external device can communicate with the non-contact information medium using the carrier having the first frequency as the non-contact information medium and the carrier frequency, the external device generates the non-contact information medium using the first frequency. A second frequency different from the first frequency
And a communication unit coupled to the base material and electromagnetically coupled to the external device.

According to the communication system and the communication auxiliary device of the first aspect of the present invention, the non-contact information medium performs wireless communication with an external device directly or via the communication auxiliary device. The communication assisting device can assist the communication between the non-contact information medium and the external device by increasing the second frequency. Different transmission data can be assigned to the first frequency and the second frequency. In the communication system according to the second aspect of the present invention, the second communication auxiliary device can achieve the same effect. Communication can be assisted.

In the communication system according to the first aspect, the communication auxiliary device merely increases the frequency and does not change the frequency when relaying communication between the non-contact information medium and the external device. If the normal direction of the antenna of the communication auxiliary device and the antenna of the external device match, the communicable distance of the external device is extended. If the antenna of the communication auxiliary device is inclined with respect to the normal direction of the antenna of the external device, the tiltable angle of the non-contact information medium with respect to the external device increases. The communication assist device has one or more resonance circuits, and each resonance circuit can resonate at the second frequency. Optionally, an amplifier may be provided in the communication auxiliary device to amplify radio waves used for wireless communication.

Other objects and further features of the present invention will be made clear by the embodiments described below with reference to the accompanying drawings.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A communication system 1 according to the present invention will be described below with reference to the accompanying drawings. In each figure,
The members with the same reference numbers represent the same members, and the members with the same reference numerals added with the alphabets represent the corresponding deformed members, and redundant description will be omitted. Further, unless otherwise specified, the reference numbers are assumed to be all the same reference numbers with alphabets.

FIG. 1 shows the configuration of a communication system 1 according to a first embodiment of the present invention. As shown in FIG. 1, the communication system 1 of the present invention includes a non-contact information medium 10, an external device 20, and a communication auxiliary device 30. In this embodiment, a non-contact IC card is used as a typical example of the non-contact information medium 10, and a reader / writer is used as a typical example of the external device 20. Accordingly, reference numerals 10 and 20 summarize these.
More specifically, the external device 20 illustrated in FIG. 1 is an antenna unit 24 of the external device 20 described later.

The non-contact IC card 10 is generally a so-called ISO (International Organization: International Organization) having the same dimensions as a credit card.
ation for Standardizatio
n) Size (length 54 mm, width 85.6 mm, thickness 0.7)
6 mm), and communicates with a reader / writer (R / W) 20 using electromagnetic (magnetic) waves. The non-contact IC card 10 may have a built-in battery. However, it is preferable that the non-contact IC card 10 be battery-less in order to avoid trouble caused by deterioration of the built-in battery and to reduce the size of the chip. Therefore, hereinafter, the non-contact IC card 10 can exchange data with the reader / writer 20 using radio waves and obtain operating power from radio waves received from the reader / writer 20 by electromagnetic induction. Non-contact IC card 1
0 has the ISO size. However, the non-contact information medium 10
If a non-contact IC tag is used, it can be any shape (for example, pendant shape, coin shape,
Key shape, card shape, tag shape, etc.).

The non-contact information medium 10 of the present invention is an external device 2
Although the wireless communication can be performed in a non-contact manner with 0, this does not exclude the function of the present invention to contact and communicate with the external device 20. For example, the non-contact information medium 10 can be configured as a combination card having both functions of a contact IC card and a non-contact IC card by incorporating a contact IC chip.

The present invention does not prevent the non-contact information medium 10 from being applied to a card medium having a magnetic stripe. In this case, the non-contact information medium 10 of the present invention has a function as a magnetic card such as a credit card and a cash card. further,
Optionally, the non-contact information medium 10 may be formed with an emboss, a sign panel, a hologram, a stamp, a hot stamp, an image print, a photograph, and the like.

The non-contact IC card 10 has an antenna coil 14 and an IC chip 16 on a base 12, as shown in FIGS. Here, FIG. 2 is a block diagram showing the configuration of the non-contact IC card 10. FIG. 2 conceptually shows the antenna coil 14. In the actual non-contact IC card 10, the antenna coil 14 is formed so as to surround the IC chip 16, for example, as shown in FIG. Here, FIG. 3 is a schematic perspective plan view of the non-contact IC card 10. FIG. 4 shows an IC chip 16.
It is a more detailed block diagram of each part. The substrate 12 is made of, for example, plastic. Optionally, contactless I
The C card 10 may further have a display, a keyboard, and the like (not shown) on the base material 12 to achieve further multifunctionality.

Referring to FIG. 2, the IC chip 16 includes a power supply circuit 102, a transmission / reception circuit 104, and a memory 108.
And preferably a logic control circuit 106 and a clock (not shown) are built in the substrate 100. Referring to FIG. 4 showing details of the IC chip 16, a reset signal generation circuit 120 is connected to the power supply circuit (PS) 102, and the reset signal generation circuit 120 is connected to a reset terminal of the logic control circuit 106. (RST). The transmission / reception circuit 104 includes a detector (DET) 110,
It includes a modulator (MOD) 114, a decoder (DEM) 116 and an encoder (ENC) 118. The demodulator 116 and the encoder 118 are connected to the data terminals DI and DO of the logic control circuit 106, respectively. If necessary, a decoder including a D / A converter or the like may be arranged as an independent member at a stage subsequent to the demodulator 116. Such a decoder may form one codec circuit with the encoder 118. The IC chip 16 includes a timing circuit (TIM) 112 for generating various timing signals and a carrier frequency fc.
Divider 122 that divides frequency and generates a subcarrier frequency
Is further provided. The timing circuit 112 is connected to a clock terminal (CLK) of the logic control circuit 106. The logic control circuit 106 is connected to the memory 108 via the memory terminal (M).

The non-contact IC card 10 does not include a battery as described above, and the power supply circuit 102
4 is an operating power VD used for each part of the IC chip 16 by electromagnetic induction from a received radio wave (carrier frequency fc).
Generate D. When the operation power VDD is generated, the reset signal generation circuit 120 resets the logic control circuit 106 to prepare for a new operation. The carrier frequency fc is also supplied to the frequency divider 122. Divider 12
M of 2 is set to, for example, 16 or 32. Divider 1
Reference numeral 22 is connected to the timing circuit 112, and generates a subcarrier frequency fs described later in synchronization with a timing signal (clock) generated by the timing circuit 112.

The receiving section of the transmitting / receiving circuit 104 includes the detector 11
0 and a demodulation circuit 116. The received signal of the carrier frequency fc is detected by the detector 110, and the demodulation circuit 116 restores the baseband signal to obtain data from the detected signal. The restored baseband signal (and, if necessary, a decoded signal thereafter) is sent to the logic control circuit 106 as a data signal DI.

The transmitting section of the transmitting / receiving circuit 104 includes the modulator 11
4 and an encoder 118. Any configuration known in the art can be used for modulator 114 and encoder 118. In order to transmit the data, the carrier is changed according to the transmission data and transmitted to the coil 14. As the modulation method, for example, ASK for changing the amplitude of the carrier (carrier) frequency, PSK for changing the phase, and the like can be used. In this embodiment, so-called load modulation is used. Load modulation modulates medium power (load) according to subcarriers (subcarriers). As a result, the amplitude of the carrier (carrier) is modulated using the subcarrier frequency.

As described above, in the present embodiment, the carrier frequency fc (for example, 13.56 MHz) is divided by the frequency divider 122.
Subcarrier frequency fs
(For example, 847.5 kHz = fc / 16). However, the subcarrier that does not interfere with the carrier may be generated by a device other than the frequency divider. The subcarrier frequency fs is sufficiently lower than the carrier frequency fc. The encoder 118 encodes (bit-encodes) the data DO to be transmitted with a predetermined code (for example, Manchester encoding or PSK encoding), and then modulates the data DO at the subcarrier frequency fs. Sent. FIG. 5 shows an example of a load modulation waveform using the Manchester code.

By utilizing the subcarrier frequency fs, transmission data can avoid interference from the carrier frequency fc which is a source of operating power of the non-contact information medium 10, so that communication reliability is improved. In this embodiment, as described above, the reader / writer 20 stores the data in the non-contact IC card 10.
Before using subcarriers.

The modulator 114 and the demodulator 116 are controlled by the logic control circuit 106 so that the timing circuit 11
2 operates in synchronism with the timing signal (clock) generated by the control signal 2. The logic control circuit 106 can be realized by a CPU. The memory 108 stores ROM, RAM, EEPROM and / or FRAM for storing data.
And so on. The non-contact IC card 10 can communicate with the reader / writer 20 based on the data, and the logic control circuit 106 can perform a predetermined process. For example, the memory 108 can store ID information, a value such as a predetermined amount of electronic money, a transaction record, and the like, and the logic control circuit 106 can execute a predetermined transaction (for example, purchasing a ticket or depositing electronic money). This value can be increased or decreased. Since the configuration and operation of these components can be easily understood by those skilled in the art, detailed description will be omitted.

The antenna coil 14 is electrically connected to the IC chip 16 and is electromagnetically coupled to a transmitting / receiving coil 32 of the communication auxiliary device 30 described later in a non-contact manner. The positional relationship between the antenna coil 14 and the transmitting / receiving coil 34 will be described later. The communication distance of the antenna coil 14 is about 10 cm with respect to the normal direction of the antenna coil 14. The antenna coil 14 has a desired size, shape, self-inductance, and mutual inductance according to a positional relationship with the communication auxiliary device 30, a mounting area, and other conditions. For example, when viewed from above, the antenna coil 14
Can have a desired shape such as a circle, a square, and an ellipse. The antenna coil 14 is formed by a wire bonding method or TAB (Tape Automated B
connected to the IC chip 16 by, for example, an operating method.

The reader / writer 20, as shown in FIG.
It has a control interface unit 22 and an antenna unit 24, both of which are connected by a cable 26. Here, FIG. 6 is a block diagram showing the configuration of the reader / writer 20. The reader / writer 20 transmits and receives the radio wave W having the carrier frequency fc to and from the non-contact IC card 10, and communicates with the non-contact IC card 10 using wireless communication. Note that the radio wave W has a carrier frequency f in an arbitrary frequency band.
c (eg, 13.56 MHz) can be used. The reader / writer 20 is further connected to an external host device (not shown) (a processing device, a control device, a personal computer, a display, etc.) via the control interface unit 22.
It is connected to the.

The control interface unit 22 includes a transmission circuit (modulation circuit) 202 and a reception circuit (demodulation circuit) 204
And a controller 206. Transmission circuit 2
02 modulates data from a further external host device using a carrier frequency fc, converts the data into a transmission signal, and transmits the transmission signal to the antenna unit 24. Reader / writer 2
When data is transmitted from 0 to the non-contact IC card 10, the carrier frequency fc of high intensity is used for modulation. Modulation methods include Modified Miller and N
A modulation scheme available in the industry such as RZ can be used.

The receiving circuit 204 converts a signal received from the non-contact IC card 10 through the antenna unit 24 into a baseband signal to obtain data, and transmits the data to a further external host device (not shown). The transmission circuit 202 and the reception circuit 204
In an actual circuit, as shown in FIG.
08 and 210 and are driven by these drive circuits. Here, FIG. 5 is a schematic perspective plan view of the reader / writer 20. It should be noted that those skilled in the art
02, since the operation and configuration of the receiving circuit 204 and the driving circuits 208 and 210 can be easily understood and realized, detailed description is omitted here.

The antenna section 24 has, for example, an antenna coil 212 and a matching circuit 216 as shown in FIG. FIG. 7 shows a specific configuration in which the matching circuit 216 includes a resistor and a capacitor.

Next, a communication auxiliary device 30 functioning as a communication auxiliary device in the communication system 1 of the present invention will be described. First, the configuration of the communication auxiliary device 30 is shown in FIGS.
This will be described with reference to FIG. Here, FIG. 8 shows the first embodiment of the present invention.
It is an outline circuit diagram of communication auxiliary equipment 30 of an example. FIG.
FIG. 9 is a perspective view of a more specific communication auxiliary device 30 for realizing the circuit of FIG. 8.

As shown in FIG. 8, the communication assist device 30 of the present invention has a resonance circuit including a transmission / reception coil 32 and a resonance capacitor 34 built in a base material 36. Transmitter / receiver coil 3
2 can be realized as an antenna coil surrounding the resonance capacitor 34 as shown in FIG. The formation of the antenna coil 32 can be realized in the same manner as the formation of the antenna coil 14 in the non-contact IC card 10. It can be formed by any method known in the art. Optionally, the coil 32 is provided with a shield for noise removal. The transmission / reception coil 32 can be configured as a spiral planar coil or a multiple spiral coil, which is an air-core coil, or a planar coil with a ferrite core or a ferrite bar antenna.
Further, as the transmission / reception coil 32, an antenna known in the art such as a dipole antenna, a monopole antenna, a loop antenna, a slot antenna, and a microstrip antenna other than the antenna coil can be applied.

The capacitor 34 is made of, for example, a copper plate. The capacitor 34 may optionally include a dielectric film (not shown) made of, for example, polyethylene or PET (polyethylene terephthalate). Further, a plurality of capacitors may be provided as a matching circuit instead of one capacitor 34. Alternatively, the capacitor 34 may be integrated with the coil 32 on a ceramic substrate (not shown).

First, the communication assisting device 30 has a function of easily and inexpensively relaxing the restriction on the communication distance between the non-contact information medium 10 and the reader / writer 20. Referring to FIG. 1, in a conventional communication system including a reader / writer 20 and a non-contact information medium 10 without a communication auxiliary device 30, a (non-contact IC card 10) (an antenna coil 14 thereof)
Is directly above the reader / writer 20 (the antenna unit 24 thereof), and the distance d = d * at which the transmission data modulated using the carrier frequency fc can be recognized is, for example, 10 cm.
It is about. The distance at which the transmission data modulated using the subcarrier frequency fs described above can be recognized is much smaller than this because the intensity of the subcarrier frequency fs is weak. Therefore, it is required that transmission data modulated using the subcarrier frequency fs also have the same communication distance as transmission data modulated using the carrier frequency fc.
The communication distance is restricted by the shape and size of the antenna coil 14 and also restricted by the Radio Law which regulates weak radio waves. In the communication between the non-contact information medium 10 and the reader / writer 20, the carrier frequency f
c or the subcarrier frequency fs is used as the center frequency. Further, a sideband is added to the center frequency by the modulation circuit. Since the Radio Law regulates the intensity of the transmitted center frequency and sideband radio waves, simply increasing the transmitted radio wave to extend the communication distance may violate the Radio Law. Therefore, it is required to extend the communication distance without increasing the transmitted radio wave.

In this regard, a proposal is made to insert the non-contact IC card 10 into a communication device capable of storing the non-contact IC card 10 and to convert the carrier frequency to another frequency and communicate with the reader / writer 20 using a unique protocol and communication format. There is also. However, this requires the user to bother with a non-contact IC.
The card 10 must be inserted into such a communication device, and a communication device having a frequency conversion function is expensive.

In view of the above, the present inventor has proposed that the non-contact I
The communication distance in the case of using the subcarrier frequency fs simply and inexpensively without changing the communication protocol, carrier frequency fc, radio wave intensity, communication format, etc. of the conventional communication system including the C card 10 and the reader / writer 20 Just figured out how to extend. As described above, the present invention does not require any change such as enlarging the antenna 14 of the non-contact IC card 10 which has been conventionally used.
It can be applied to the current communication system as it is.

The communication method is such that the communication auxiliary device 30 is arranged so that the normal direction of the antenna coil 32 of the antenna unit 24 of the reader / writer 20 matches the normal direction of the antenna coil 32 of the communication auxiliary device 30. is there. Here, the distance between the non-contact IC card 10 and the reader / writer 20 is about 10 cm. The distance d between the reader / writer 20 and the communication auxiliary device 30 changes within the range of this distance so that the communication auxiliary device 30 is electromagnetically coupled to the reader / writer. In addition, the user only needs to hold the non-contact IC card 10 over the reader / writer 20 as before, and there is no inconvenience such as inserting the card into the communication device.

The communication auxiliary device 30 is not substantially used when transmitting data from the reader / writer 20 to the non-contact IC card 10. This is because the reader / writer 20 modulates transmission data with the carrier frequency fc as described above, and this transmission data can be transmitted to the contactless IC card 10 without communication assistance. Therefore,
The communication auxiliary device 30 relays radio waves W transferred from the non-contact IC card 10 when data is transmitted from the non-contact IC card 10 to the reader / writer 20 where transmission data is modulated by the subcarrier frequency fs, and 2
Operate to transfer it to 0.

The communication assisting device 30 includes the non-contact information medium 10
Without having to be placed between the
For example, as shown in FIG. 10, it may be arranged directly above the non-contact information medium 10. Here, FIG. 10 is a perspective view showing a configuration of a communication system 1B which is a modification of the communication system 1 shown in FIG.

The communication system 1B shown in FIG. 10 utilizes the re-radiation of the communication auxiliary device 30, and the communication auxiliary device 30 is conceptually similar to the communication system 1 shown in FIG.
Relays data from the C card 10 to the reader / writer 20
Can be interpreted as transferring it to

The communication auxiliary device 30 of the present invention can use a resonance circuit, does not change the carrier frequency fc, and changes the intensity of the radio wave of the reader / writer 20 already set in the conventional communication system. Nothing to do. The communication auxiliary device 30 has a simple configuration and is inexpensive, and extends the maximum communication distance d while preventing the communication system from becoming expensive.

As shown in FIG. 8, the communication auxiliary device 30
An antenna coil 32 having a self-inductance L and a resonance capacitor 34 having a capacitance C are provided. The resonance frequency fr of the circuit shown in FIG. 8 is (1 / 2π) (LC) − ／. If the value of the resonance frequency fr is made to coincide with the subcarrier frequency fc (= fc / m), the circuit shown in FIG. 7 resonates and tunes to fs to flow a large resonance current through the transmission / reception coil 32 and the resonance capacitor 34. In addition, the resonance current can be supplied to the non-contact IC card 10 or the reader / writer 20 in a non-contact manner. However, in an actual circuit, (1 / 2π) (LC)
In some cases, -1/2 cannot be matched with the carrier frequency fr. Therefore, even in such a case, in order to obtain a tuning effect, a double tuning circuit composed of a plurality of resonance circuits may be used.

Hereinafter, such an embodiment will be described with reference to FIGS. 11 and 12. FIG. Here, FIG. 11 shows the second embodiment of the present invention.
It is an outline circuit block diagram of 30 A of communication auxiliary apparatuses of an Example.
FIG. 12 is a perspective view of a more specific communication auxiliary device 30A for realizing the circuit of FIG.

The communication auxiliary device 30A uses a double tuning circuit composed of a plurality of resonance circuits. As is well known, the double-tuned circuit has a bimodal gain frequency characteristic and can obtain a wide frequency band. It should be noted that other circuits having bimodality can also be applied to the communication auxiliary device.

As shown in FIG. 11, the communication assist device 30A includes two resonance circuits each including a pair of coils 32A and 32B and a pair of capacitors 34A and 34B. The coils 32A and 32B have different numbers of turns, and have self-inductances L1 and L2, respectively. The coupling coefficient (mutual inductance) M is set high so that the coils 32A and 32B are tightly coupled. The capacitors 34A and 34B have capacitances C1 and C2, respectively. The relationship between self-inductance and capacitance is, in principle, (1 / 2π) (L1C1)-）
= (1 / 2π) (L2C2) -1 / 2 = subcarrier frequency fr. However, even if both or one of them does not match the subcarrier frequency fr due to an error between the elements or the like. Can generate a sufficiently large induced current near the subcarrier frequency fr. The communication assisting device 30 may be formed by laminating two structures shown in FIG. 9, but in FIG. 12, the above-described components are housed in one substrate 36 </ b> A. A method of manufacturing the communication auxiliary device 30A having the structure shown in FIG. 12 is easy for those skilled in the art, and a detailed description thereof will be omitted.

The communication auxiliary device 30 may be replaced with a communication auxiliary device 30B shown in FIG. Here, FIG.
FIG. 14 is a schematic circuit configuration diagram of a communication auxiliary device 30B according to a third embodiment of the present invention. In view of the function of the communication auxiliary device 30 as a repeater, a unique amplifier may be added to the communication auxiliary device 30. In FIG. 13, the radio wave W received by the receiving coil 32C is amplified by an amplifier 33 to which driving power is given from a power supply 31, and transmitted from a transmitting coil 32D. Therefore, the signal output from the transmission coil 32D is sufficiently amplified not only at the center frequency but also at the sideband. Amplifier 33 can be any amplifier known in the art, including transistors.

Next, a communication system 1B according to a second embodiment of the present invention will be described with reference to FIG. FIG. 14 is a perspective view showing a configuration of a communication system 1B according to a second embodiment of the present invention. The communication system 1 </ b> B of the present invention is characterized in that the communication auxiliary device 30 is arranged obliquely with respect to the reader / writer 20.

Communication auxiliary device 3 in communication system 1B
0 relaxes the relative posture of the non-contact IC card 10 required by the reader / writer 20 from the directivity of the antenna 212 (that is, the inclination angle with respect to the reader / writer 20). In the conventional communication system including the non-contact IC card 10 and the reader / writer 20, the subcarrier frequency fs
To obtain the maximum communication distance with respect to (and the carrier frequency fc), the non-contact IC card 10
Must be arranged parallel to However, it is difficult to always arrange the non-contact IC 10 in parallel with the reader / writer 20. For example, at a ski lift lift platform, the skier must store the non-contact IC card 10 as a ticket on the unstable arm of the ski wear and hold it over the reader / writer 20 at the lift platform. In addition, at an automatic ticket gate at a station, a person passing through the ticket gate must walk over the reader / writer 20 with the non-contact IC card 10 as a ticket while walking. For this reason, it is required that reading can be performed without completely arranging the non-contact IC card 10 in parallel with the antenna unit 24 of the reader / writer 20.

Therefore, in the communication system 1B of the present invention, the antenna coil 32 of the communication auxiliary device 30 is connected to the reader / writer 20.
Are arranged at an angle with respect to the normal line of the antenna 212 so that the non-contact IC card 10
As long as communication is possible, the communication distance with the reader / writer 20 can be maintained by the same distance as when both are arranged in parallel. The communication assisting device 30 can be physically coupled to the reader / writer 20 by using, for example, a hinge or the like.
The inclination angle β with respect to the C card 10 can be adjusted manually or automatically. It is easy for a person skilled in the art to realize such a physical structure, and a detailed description thereof will be omitted here.

In the communication system 1B, a non-contact IC
When the antenna 14 of the card 10 is in the normal direction of the antenna 32 of the communication auxiliary device 30, the maximum communication distance with the communication auxiliary device 30 can be secured. Therefore, if a plurality of communication assisting devices 30 having different inclination angles with respect to the reader / writer 20 are arranged, the restriction on the inclination angle that the non-contact IC card 10 should have is alleviated accordingly. FIG. 15 shows a communication system 1C which is a modification of the communication system 1B provided with two communication auxiliary devices 30. In this case, for example, the data is transferred from the reader / writer 20 to the non-contact IC card 10 via one of the communication auxiliary devices 30. In addition, the number of the communication assisting devices 30 is 2
Of course, it is possible to increase the number more.

Therefore, in the communication system 1C shown in FIG.
Must be electromagnetically coupled to the non-contact IC card 10 as long as only the communication auxiliary device 30 used for relaying is electromagnetically coupled to the non-contact IC card 10.

It should be noted that the communication systems 1B and 1C according to the present invention
It must not be placed directly above the. Therefore, in the communication system 1 shown in FIG.
0 may be inclined. However, in this case, the effect of reducing the inclination angle of the non-contact IC card 10 is emphasized rather than the effect of extending the communication distance. Further, as shown in FIG.
It may be inclined at the upper part of the non-contact IC card 10. In this case, it goes without saying that the communication auxiliary device 30 does not have to be directly above the reader / writer 20.

In the above description, the communication auxiliary device 30 increases and expands the subcarrier frequency fs, thereby expanding the communication distance of the modulated transmission data. However, the original maximum communication distance between the reader / writer 20 and the non-contact IC card 10 can be extended by combining a communication auxiliary device that similarly increases and expands the carrier frequency fc with the above-described communication system. Therefore, the present invention can be applied to a case where a non-contact information medium such as an on-coil IC chip having a short communication distance is used.
More specifically, for example, in FIG. 10, one of the two circuits is replaced with a resonance circuit that resonates at the carrier frequency fc. Since such a resonance circuit can be easily achieved by making the above-mentioned fr equal to fc, a detailed description is omitted here. Needless to say, a desired number of resonance circuits resonating at the carrier frequency fc can be independently added to the circuit of FIG. Similarly, in FIG. 15, one of the two communication auxiliary devices may be replaced with a communication auxiliary device that increases and expands the carrier frequency fc. Further, a communication auxiliary device for enhancing and expanding an arbitrary frequency other than fc and fs may be provided. As a result, data can be managed for different frequencies, so that the degree of freedom of use is expanded.

Although the preferred embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the invention.

For example, it should be noted that the reader / writer in the case where the communication assistant device 30 and the reader / writer 20 are integrally configured so that the reader / writer has a plurality of antenna units is also within the scope of the present invention. Must. Also,
A non-contact information medium may likewise be integrated with the communication aid. Also, as described with reference to FIG.
In an actual communication system, the communication auxiliary device 30 is often used in a mode in which the communication auxiliary device 30 and the reader / writer 20 are physically coupled. A communication system having such a reader / writer should not be construed as including the communication auxiliary device of the present invention, but is understood to include the functions of both the communication auxiliary device 30 and the reader / writer 20 of the present invention. Should. In such a reader / writer, the control interface 22 may be commonly connected to the coils of the plurality of antenna units.

[0063]

According to the communication system and the communication auxiliary device according to the first aspect of the present invention, different transmission data can be assigned to the first frequency and the second frequency, respectively, so that mutual interference during transmission can be reduced. The reliability of data transmission can be increased by reducing or eliminating. In addition, since the communication auxiliary device can relay the communication between the non-contact information medium and the external device, the non-contact information medium can indirectly communicate with the external device via the communication auxiliary device even if the non-contact information medium cannot directly communicate with the external device. , And the degree of freedom of communication for the contactless information medium and its user increases. In the communication system according to the second aspect of the present invention, the second communication auxiliary device can achieve the same effect, but the first communication auxiliary device has the first communication auxiliary device.
The communication distance between the non-contact information medium and the external device due to the frequency of the communication is also increased. Therefore, for example, even if the communication distance using the first frequency of the non-contact information medium is short, the communication distance can be extended, so that the present invention can be applied to an on-coil IC chip and the like.

The relay function of the communication auxiliary device is to increase the communication distance between the external device and the non-contact information medium, and / or to adjust the attitude and / or attitude of the non-contact information medium with respect to the external device.
Alternatively, an effect such as relaxation of a position constraint is brought about. As a result, the communication auxiliary device of the present invention can easily and inexpensively eliminate the disadvantages of the conventional communication system. The communication system of the present invention may include a plurality of communication auxiliary devices for enhancing the same or different frequencies.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a configuration of a communication system according to a first exemplary embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a contactless IC card of the communication system shown in FIG.

FIG. 3 is a schematic perspective plan view of the non-contact IC card shown in FIG. 2;

FIG. 4 is a more detailed block diagram of each part of the IC chip shown in FIGS. 2 and 3;

5 is an example of a waveform diagram of a signal transmitted from the non-contact IC card of FIG. 2;

FIG. 6 is a block diagram illustrating a configuration of a reader / writer of the communication system illustrated in FIG. 1;

7 is a schematic perspective plan view of the reader / writer shown in FIG. 6;

FIG. 8 is a schematic circuit configuration diagram of a communication auxiliary device of a first embodiment of the present invention applicable to the communication system of the present invention.

9 is a perspective view of a more specific communication auxiliary device for realizing the circuit of FIG. 8;

FIG. 10 is a perspective view showing a modification of the communication system shown in FIG.

FIG. 11 is a schematic circuit diagram of a communication auxiliary device according to a second embodiment of the present invention applicable to the communication system of the present invention.

FIG. 12 is a perspective view of a more specific communication auxiliary device for realizing the circuit of FIG. 11;

FIG. 13 is a schematic circuit diagram of a communication auxiliary device according to a third embodiment of the present invention.

FIG. 14 is a perspective view illustrating a configuration of a communication system according to a second example of the present invention.

15 is a perspective view showing a modification of the communication system shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Communication system 10 Non-contact information medium 14 Antenna 16 IC chip 20 External device 22 Control interface 24 Antenna part 30 Communication auxiliary device 32 Transmission / reception coil 34 Resonance capacitor 36 Base material 122 Divider 212 Antenna

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5B035 AA11 BA03 BB02 BB09 BC00 CA01 CA11 CA12 CA22 CA23 5B058 CA17 CA40 KA29 YA03 5J070 AD01 AK40 BC08 BC29 BC35 BC36 5K012 AA01 AB05 AC06 AC08 AC10 AC12 AD05 AE02 BA02

Claims (12)

[Claims] An external device capable of communicating with the non-contact information medium using a non-contact information medium, a carrier having a first frequency as a carrier frequency, and the first frequency A communication auxiliary device electromagnetically coupled to the external device, the communication device being capable of enhancing a second frequency different from the generated first frequency. 2. The communication system according to claim 1, wherein said first frequency is a carrier frequency, and said second frequency is a subcarrier frequency obtained by dividing said carrier frequency. 3. The external device modulates first data to be transmitted to the non-contact information medium using the first frequency, thereby converting the first data to the non-contact information. A first transmission unit that transmits the data to a medium, wherein the non-contact information medium modulates second data to be transmitted to the external device using the second frequency, and modulates the second data by using the second frequency. 2. The communication system according to claim 1, further comprising a second transmission unit that transmits the second data to an external device. 4. The non-contact information medium has a first antenna, the external device has a second antenna, and the communication auxiliary device matches a normal direction of the second antenna. The communication system according to claim 1, further comprising a third antenna. 5. The non-contact information medium has a first antenna, the external device has a second antenna, and the communication auxiliary device is inclined with respect to a normal direction of the second antenna. The communication system according to claim 1, further comprising a third antenna. 6. The non-contact information medium has a first antenna, the external device has a second antenna, the communication auxiliary device has a third antenna, and the first antenna is 2. The communication system according to claim 1, wherein communication can be performed with the second antenna via the third antenna at a position separated from a normal line of the second antenna. 3. 7. The communication system has a plurality of the communication auxiliary devices, and at least one of the communication auxiliary devices is indirectly electromagnetically coupled to the external device via any one of the other communication auxiliary devices. The communication system according to claim 1, wherein 8. A non-contact information medium, an external device capable of communicating with the non-contact information medium using a carrier having a first frequency as a carrier frequency, and enhancing the first frequency A first communication auxiliary device electromagnetically coupled to the external device; and a second communication auxiliary device electromagnetically coupled to the external device, the second communication auxiliary device being capable of enhancing the second frequency. system. 9. The method according to claim 1, wherein the first device is capable of communicating with the non-contact information medium using a carrier having a first frequency as a carrier frequency with the non-contact information medium. A second frequency different from the first frequency generated using the frequency;
And a communication unit coupled to the base material and electromagnetically coupled to the external device. 10. The communication system according to claim 9, wherein the communication unit has a resonance circuit that can resonate at the second frequency. 11. The communication auxiliary device according to claim 9, wherein the communication unit has a double-tuned circuit capable of resonating at the second frequency. 12. The communication auxiliary device according to claim 9, wherein the communication unit has a power supply and an amplifier connected to the power supply.