JPH1175329A - Non-contact type ic card system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maximize the power transmission efficiency from a reader or writer device to a proximity wireless card, by setting the respective Q values of a resonance circuit of the reader or writer device and the resonance circuit of an IC card using the Q of the whole communication route. SOLUTION: A reader and/or writer unit 1 constitutes a resonance circuit using a capacitor 104, an antenna drive impedance 120 and an R/W antenna coil 101. A wireless card 2 constitutes a resonance circuit using a card antenna coil 201, a capacitor, and a resistor 220. In such a system, the antenna drive impedance 120 is set so as to maximize the reception efficiency at the proximity wireless card 2 in the target communication distance, and the respective Qs of the resonance circuits are set so as to obtain the necessary bandwidth to secure the sufficient signal level to the target communication speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a cash dispenser, electronic money, an automatic ticket gate system, an entrance / exit management system, a cash card in a public telephone, a credit card, a ticket, a commuter pass, a coupon, a management card, The present invention relates to a non-contact IC card system for performing power transmission and communication for close proximity wireless operation between a non-contact IC card such as an ID card, a license, and a telephone card, and a reader or / and a writer device.

[0002]

2. Description of the Related Art Conventionally, it is known that power is supplied from a power supply side to a proximity wireless card (IC card) in a contactless manner by using light or a magnetic field.

For example, cash cards, credit cards, tickets, commuter passes, and the like used at ticket gates, buses, entrances and exits of stations are converted into IC cards, and users can use the IC cards at ticket gates, buses, and other stations of the stations. When the card passes through a reader / writer provided at an entrance / exit in a non-contact manner, power and / or signals are exchanged between the reader / writer and the card by an electromagnetic coupling method or an electromagnetic induction method. This is a non-contact IC card system (proximity wireless card system).

In general, such a non-contact IC card system includes a reader / writer and an IC card so that a power transmission wave and a data communication modulation wave can be transmitted from the reader / writer side to the IC card side with high efficiency. It was designed separately.

More specifically, Q (= f0 / BW, f0: center frequency, BW: a bandwidth that is -3 dB from the gain of the center frequency f0) derived from the frequency characteristics shown in FIG. Had designed a reader / writer and an IC card.

[0006]

However, when a reader / writer superimposes a data signal (data communication modulation wave) on a power transmission wave for transmission / reception, the contactless IC card system must satisfy the following conditions. Must.

(1) On the IC card side, it is necessary to design the bandwidth BW so that the gain becomes a certain value or more, as wide as possible, so that all the modulated waves for data communication can be received without fail. That is, it must be designed so that Q is small.

(2) In order to supply sufficient power to the IC card side, the power transmission frequency, for example, the gain of the above-mentioned center frequency must be increased as much as possible. in this case,
In general, Q must be designed to be large. It should be noted that merely increasing the power transmission wave transmitted from the reader / writer has no legal restrictions on the power transmission wave.
Although there is no problem because the ISM band is used, it must be considered that the data communication modulation wave superimposed on the power transmission wave cannot satisfy the legally regulated value in the used frequency band (outside the ISM band).

As described above, the conditions (1) and (2) require that Q be reduced on the one hand and Q be increased on the other hand, and the reader / writer and I
Determining the Q of each C card is a very difficult task.

For example, when the Q of the resonance circuit of each antenna section of the reader / writer and the IC card is increased to set the Q of the entire transmission path formed by the reader / writer and the card to be high, reception induction at the card is induced. Power increases, but
This means that the necessary bandwidth for securing a sufficient signal level for the target communication speed between the reader / writer and the card cannot be obtained.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and is intended to solve the above problem with respect to a resonance circuit of a reader / writer device and a proximity wireless card (IC card) from the reader / writer device. Proximity wireless card (I
It is an object of the present invention to provide a completely novel method for maximizing the power transmission efficiency to a C card and easily providing a required bandwidth for a target communication speed.

[0012]

[Means for Solving the Problems] Therefore, we
The objective was achieved by allocating and designing the Q of each reader / writer and IC card using the Q of the entire IC card system.

More specifically, the transmission of power or / and signals between the reader / writer and / or the writer device and the IC card is performed in a non-contact manner, and the reader / writer and / or the IC card respectively transmit the power or / and signal. And / or a non-contact type IC card system comprising a resonance circuit including an antenna coil for transmitting the signal, a capacitance set to be tuned to a power transmission frequency for transmitting the power, and a driving impedance of the antenna coil. , The reader or /
By using the Q of the entire communication path including the writer device and the IC card, the respective Qs of the resonance circuit of the reader and / or the writer device and the resonance circuit of the IC card are set.

A contactless IC card system for transmitting electric power and / or signals between a reader or / and a writer device and an IC card in a contactless manner,
The transmission of the signal is determined from the characteristics of the Q of the entire transmission path derived by setting the antenna driving impedance of the reader or / and the writer device to be approximately equal to the impedance of the IC card from the antenna of the reader or / and the writer device. Calculate Q3 that makes it possible to obtain a desired bandwidth with respect to the speed, and calculate the Q3 and the reader or / and / or the power transfer efficiency from the reader / writer device to the IC card that maximizes the power transmission efficiency. Writer device
By using the relationship between Q1 and Q2 of the IC card, Q1 and Q2 of the reader / writer device and the resonance circuit of the IC card are set.

Alternatively, there is provided a contactless IC card system for transmitting electric power and / or signals between a reader or / and writer device and an IC card in a non-contact manner, wherein the reader / writer device and the IC card are transmitted. By using the Q of the entire communication path consisting of
And Q for each of the writer device and the IC card.

With such a configuration, a non-contact IC card comprising a reader / writer and / or a writer and an IC card for transmitting and receiving power and signals to and from an adjacent IC card by an electromagnetic coupling method or an electromagnetic induction method. In a system (proximity wireless card system), the reception efficiency of an IC card is maximized at a target communication distance, and a necessary bandwidth for easily securing a signal level sufficient for a target communication speed is easily obtained. be able to.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments according to the present invention will be described with reference to the drawings.

FIG. 1 shows a non-contact card which is passed or approached in a non-contact manner from, for example, a reader or / and a writer unit (device) 1 provided at a ticket gate, a bus, an entrance / exit, or a predetermined place according to the present invention. (Proximity wireless card: IC card)
FIG. 2 is a diagram showing a schematic configuration of a power transmission and communication system for transmitting power and performing communication with an electromagnetic coupling system 2 or an electromagnetic induction system for example. The contactless card (proximity wireless card: IC card) 2 is held by the user and is in contact with a reader and / or writer unit 1 provided at a ticket gate, a bus or an entrance / exit, for example, up to about 10 cm. Information such as cash cards, credit cards, tickets, commuter passes, etc. is transmitted and received by electromagnetic coupling method or electromagnetic induction method by passing through a distance, and the role of cash cards, credit cards, tickets, commuter passes, etc. Is what you do.

FIG. 2 shows the configuration of the reader / writer unit (device) 1 and the non-contact card (proximity wireless card: IC card) 2 shown in FIG. 1 by an equivalent circuit. A contactless card (proximity wireless card: I
In order to simplify the C card 2, power transmission and information transmission / reception are performed by a single antenna (reader / writer antenna) 101. Therefore, in FIG. 2, between the reader / writer antenna 101 provided in the reader / writer unit 1 and the card antenna coil 201 formed in the close proximity wireless card 2, the power transmission wave and data communication modulation shown in FIG. Electromagnetic waves composed of waves (wireless)
Is used to both transmit power and transmit and receive communications.
As can be seen from FIG. 3, the power transmission wave and the signal wave in the ASK modulation method have different frequency components when viewed in the frequency domain, but the amplitude of the power transmission wave varies according to the signal speed when viewed in the time domain. Just do it. That is, in the time domain, the modulated wave obtained by multiplying the power transmission wave by the signal wave looks only as if the waveform amplitude of the power transmission wave fluctuates up and down.

The contactless card system (proximity wireless card system) shown in FIG. 2 includes an OSC (oscillator) 304 oscillating at a frequency fo, and an antenna coil driving impedance 303 when the antenna coil 301 is driven by the OSC 304. A reader / writer 300 comprising the antenna coil 301 and an antenna coil tuning capacitor 302 set to perform series resonance at a frequency fo.
And an IC card 400 composed of an antenna coil tuning capacitor 402 and a card load resistor 403 set so as to resonate in parallel with the antenna coil 401 at a frequency fo. The antenna coil 301 of the reader / writer and the antenna coil 401 of the IC card are coupled with an electromagnetic coupling or an electromagnetic coupling with an antenna coupling coefficient k. The antenna coupling coefficient k changes according to the distance between the antenna coil 301 of the reader / writer and the antenna coil 401 of the IC card. Here, for the sake of explanation, the resonance circuit on the reader / writer side is a series resonance circuit, and the resonance circuit on the IC card side is a parallel resonance circuit. However, the combination of the resonance circuits is not limited to this, and various modes can be adopted. .

Here, when the approximate expression of Q of the whole non-contact IC card system including the reader / writer unit (device) 1 and the non-contact card (proximity wireless card: IC card) 2 as described above is obtained, It looks like 1.

[0022]

(Equation 1)

This is a result obtained from a circuit equation based on the equivalent circuit shown in FIG. 2. Q3 of the entire non-contact IC card system is replaced with Q1 of the reader / writer unit.
And Q2 of the contactless IC card.
In addition, a reader or / and a writer unit (device)
1. The equivalent circuit and the contents of Equation 1 naturally differ depending on the configuration of the non-contact card (proximity wireless card: IC card) 2. In any case, the Q of the entire non-contact IC card system
3 may be obtained from the relationship between Q1 of the reader / writer unit and Q2 of the non-contact IC card.

Next, the reader / writer unit and / or the writer unit are expressed by using the relationship expressed by the expression Q1 of the entire contactless IC card system as Q1 of the reader / writer unit and Q2 of the contactless IC card. Q1 and non-contact IC
How to determine card Q2 (Q1, Q2 allocation)
Will be described with reference to FIG.

FIG. 5 shows the relationship between Q (Q2) of the IC card 4 and Q (Q3) of the entire transmission path composed of the reader / writer 3 and the IC card 4 by using Equation 1. Q of the IC card 4 (Q2) and Q of the reader / writer 3
It is the result of having simulated the relationship with (Q1). In this case, simulation is performed by substituting Equation 2 into Equation 1.

[0026]

(Equation 2)

## EQU2 ## In the circuit shown in FIG. 2, the antenna driving impedance 30 of the reader / writer is set so that the reception efficiency of the IC card at the target communication distance is maximized.
3 is equal to the impedance Zc306 when the IC card 4 is viewed from the terminal aa '305 of the reader / writer at the communication distance targeted for 3 and is derived by impedance matching.

In FIG. 5, the antenna coil 301 of the reader / writer 3 has a spiral shape with three turns [T] and an outer periphery of 100 [mm] × 100 [mm].
The antenna coil 401 of the C card 4 has a spiral shape with the number of turns [T] of 4 and has an outer circumference of 77 [mm] × 42 [m].
m], and a distance d = 30 [mm] between the reader / writer 3 and the IC card 4 (at this time, the value of the coupling coefficient k is k = 0.0
998).

For such a simulation result, Q3 of the entire transmission path can be set from the bandwidth required in the contactless IC card system at the target communication speed and the power transmission frequency to be used. Then, Q1Q2 can be uniquely set from the set Q3 using the function shown in FIG.

For example, if Q3, which is the Q of the entire transmission path, is set to 10 or less from the bandwidth required for the target communication speed, the Q of the reader / writer 3 is Q1 = 4.5-2.
2.2, Q of the IC card 4 is Q2 = 4.4 to 22.2.
It can be seen that the value should be set to 0.

As described above, in FIG. 5, since the simulation result is obtained by using the relational expression (Equation 2) in the case where the power transmission is maximized, the set Q1 and Q2 are the values that maximize the power transmission. Becomes That is, Q of the resonance circuit of each of the reader / writer 3 and the IC card 4 which can maximize the reception efficiency of the IC card 4 and obtain a sufficient bandwidth for the target communication speed is set. Can be.

From each Q thus set,
For example, if L1, L2, Rs, RL, etc. are derived using Equations 3 and 4, etc., it is possible to maximize the reception efficiency of the IC card 4 and obtain a sufficient bandwidth for the target communication speed. A possible reader / writer 3 and IC card 4 can be configured.

[0033]

(Equation 3)

[0034]

(Equation 4)

It should be noted that Equations 2 to 4 and other constituent elements C1,
Needless to say, C2 can be calculated from a circuit equation based on the equivalent circuit shown in FIG.

On the other hand, in the above description, the antenna coil 301 of the reader / writer 3 has a spiral shape with three turns [T] and an outer circumference of 100 [mm] × 100 [m].
m], and the antenna coil 401 of the IC card 4 has a spiral shape with the number of turns [T] of 4 and a circumference of 77 [mm].
× 42 [mm], a case where the distance between the reader / writer 3 and the IC card 4 is d = 30 [mm] and Q3 which is the Q of the entire transmission path is 10 or less has been described. The present invention is not limited to this, and various forms can be applied.

For example, the above reader / writer and IC
Target communication distance of 5cm using card antenna
In the following, when the Q of the entire transmission path is set to 20 or less, the Q of the reader / writer 3 is set in the range of Q1 = 3 to 40, and the Q of the IC card 4 is set in the range of Q2 = 3 to 42. I just need. Further, even when the antenna shapes of the reader / writer and the IC card are changed, the coupling coefficient k between the antennas is changed.
The present invention can be applied using Q and / or Q of the entire transmission path and / or the ratio of the communication bandwidth to the carrier frequency of the communication signal.

Further, the condition for maximizing the efficiency of power transmission: Instead of Equation 2, a relationship as shown in FIG. 5 may be simulated using a known relationship between Q1 and Q2.

Although Q3, which is the Q of the entire transmission path composed of the reader / writer 3 and the IC card 4, is used, the ratio of the communication bandwidth to the carrier frequency of the communication signal is Q
It may be used as 3.

Next, power transmission and information transfer between the reader / writer unit (device) 1 and the non-contact card (proximity wireless card: IC card) 2 according to the present invention by an electromagnetic coupling method or an electromagnetic induction method or the like. An example in which the present invention is applied to an embodiment of a device (system) that performs transmission and reception (communication) will be described.

FIG. 6 shows an OSC (oscillator) 105 for generating a high-frequency voltage of 13.56 MHz and input transmission data (DAT) for transmission to the proximity wireless card 2.
A) An encoding circuit 107 for encoding 106 and the OS
A modulation circuit 108 for modulating a 13.56 MHz high frequency voltage generated from C105 in accordance with the output signal of the encoding circuit 107; and an antenna coil driving circuit 109 for driving an antenna coil in accordance with the output signal of the modulation circuit
And the signal amplified by the antenna coil driving circuit is coupled by an inductance coupling 103, and a capacitor 10
A matching circuit (feeding circuit) 102 for matching the impedance with the antenna 4 and the antenna driving impedance 120, and generating an electromagnetic wave for power transmission and data transmission according to the output of the matching circuit 102; An R / W antenna coil 101 for receiving data transmitted by an electromagnetic wave from a card antenna coil 201 of the close proximity wireless card 2 and a signal received by the R / W antenna coil 101 are matched by a matching circuit 102 to form an inductance coupling 103. Circuit 110 for removing a noise component from a signal generated by the above, a reception amplifier 111 for amplifying a signal obtained through the filter circuit 110, and a demodulation circuit 1 for demodulating a signal amplified by the reception amplifier 111
12 and a decoding circuit 113 for decoding the signal demodulated by the demodulation circuit 112 and outputting it as received data (DATA) 114. Then, the transmission data 106
The received data 114 is connected to a host computer 115 via a network.

The proximity wireless card (contactless card: IC card) 2 receives an electromagnetic wave generated for transmitting power and transmitting data from the R / W antenna coil 101 of the R / W unit 1 and performs load switching. A card antenna coil 201 that generates an electromagnetic wave corresponding to the modulated transmission data, a 13.56 MHz power received by the card antenna coil 201 is rectified, and a transmission / reception signal is impedance-impeded using a capacitor 221 and a resistor 220. A matching / rectifying circuit 203 for matching and matching; a power supply circuit 204 for supplying a constant DC voltage power supply 205 of about 2 to 5 V at about 5 mW from the induced voltage rectified from the matching / rectifying circuit 203; Clock extraction for extracting a clock from the received signal obtained from 203 Road 206 and the matching / rectifier circuit 20
LP that removes noise components from the received signal obtained from 3
F circuit 207, waveform shaping circuit 208 for shaping the waveform of the reception signal obtained from LPF circuit 207, and load switching modulation of the transmission signal and supply to matching / rectification circuit 203 for matching and loading to supply to card antenna coil 201 Wireless chip 2 having switching modulation circuit
02 and the clock extraction circuit 206 of the wireless chip 202
The signal obtained from the frequency dividing circuit 211 for generating a signal for operating the microcomputer 214 by dividing the frequency based on the clock signal extracted in step (1) and the waveform shaping circuit 208 of the wireless chip 202 are decoded as decoded data (received data). A decoding circuit 212 input to a microcomputer (CPU) 214 and a memory for storing information as a coding circuit 213 for encoding transmission data obtained from the microcomputer 214 and inputting the data to a load switching circuit 209 of the wireless chip 202 are provided. A microcomputer (CPU) 214 that performs processing of transmission / reception data and transfer of data to / from a memory,
A chip 210 such as a CPU (CPU + interface) that receives a stable power supply 205 from a power supply circuit 204 of the wireless chip 202 is provided.

In the reader / writer unit (device) 1, a resonance circuit is formed by using the capacitor 104, the antenna driving impedance 120, and the R / W antenna coil 101. In the card (IC card) 2, a resonance circuit is configured using the card antenna coil 201, the capacitor 221, and the resistor 220. Even with the above system,
Similarly to the above embodiment, the antenna driving impedance 120 is set so as to maximize the reception efficiency of the close proximity wireless card (contactless card: IC card) 2 at the target communication distance, and The Q of each of these resonance circuits can be set so as to obtain a necessary bandwidth for securing a sufficient signal level for a communication speed to be performed.

Lastly, conventionally, the Q of the reader / writer and / or the writer device and the Q of the proximity wireless card are separately designed and set, so that the performance of the contactless IC card system is not only the performance of both, but also the performance of both. However, if the product design based on the Q of the contactless IC card system is performed using the present invention, the Q of the reader / writer and / or the Since the Q of the card can be uniquely determined and set (because the compatibility between the reader or / and writer device and the proximity wireless card can be set),
There is also an effect that it is possible to design a product in consideration of only the performance of each product as compared with the related art. That is, based on the Q of the contactless IC card system, the reader or /
By allocating the Q of the writer device and the Q of the close proximity wireless card, there is an effect that the condition becomes very easy to standardize in standardizing the reader / writer device and the close proximity wireless card.

[0045]

As described above, according to the present invention,
A reader / writer device and a proximity wireless card (I
For the resonance circuit of the C card, the power transmission efficiency from the reader or / and writer device to the close proximity wireless card (IC card) is maximized, and the bandwidth required for the target communication speed is obtained. A contactless IC card system in which each Q is set by a completely new method can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic configuration perspective view showing that power transmission and communication are performed by an electromagnetic coupling method or an electromagnetic induction method between a reader or / and writer device according to the present invention and a close proximity wireless card (IC card). is there.

FIG. 2 replaces a device (system) for performing power transmission and communication between a reader or / and writer device according to the present invention and a close proximity wireless card (IC card) by an electromagnetic coupling method or an electromagnetic induction method with an equivalent circuit. FIG.

FIG. 3 is a diagram showing a relationship between a power transmission wave and a data communication modulation wave according to the present invention.

FIG. 4 is a diagram showing the principle of Q.

FIG. 5 shows the Q of the resonance circuit of the reader or / and writer device according to the present invention, the Q of the resonance circuit of the proximity wireless card (IC card), the reader / writer device and the proximity wireless card (IC card), FIG. 6 is a diagram showing a relationship between the transmission path and the Q of the entire transmission path composed of.

FIG. 6 is a diagram showing an example of an embodiment of a reader / writer and a proximity wireless card (IC card) according to the present invention.

[Explanation of symbols]

1 ... Reader / writer unit, 2 ... Proximity wireless card (I
C card: contactless card), 101: reader / writer antenna, 102: matching circuit (feeding circuit), 104: capacitor, 105: power supply, 107: coding circuit, 108: modulator, 109: transmission amplifier, 110: filter Circuit, 1
11 receiving amplifier, 112 demodulator, 113 decoding circuit, 115 host computer, 120 antenna driving impedance, 201 card antenna, 202
Wireless chip, 203 matching / rectifying circuit, 204 power supply circuit, 206 clock extraction circuit, 207 LPF circuit,
208: waveform shaping circuit, 209: load switching circuit, 210: chip such as CPU (CPU + interface chip), 211: frequency dividing circuit, 212: decoding circuit, 213: encoding circuit, 214: microcomputer (CP)
U), 220: resistor, 221: capacitor, 300: reader / writer, 301: antenna coil, 302: antenna coil tuning capacity, 303: antenna coil driving impedance, 304: OSC (transmitter), 400: IC
Card, 401: Antenna coil, 402: Antenna coil tuning capacity, 403: Card load resistance

Continuing on the front page (72) Inventor Koichi Uesaka 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside the Hitachi, Ltd. Production Technology Laboratory Co., Ltd. Within the business division

Claims (5)

[Claims] An electric power and / or signal is transmitted between a reader or / and a writer device and an IC card in a non-contact manner, and the reader or / and the writer device and the IC card respectively transmit the electric power or / and / or the signal. A contactless IC card system comprising an antenna coil for transmitting the signal, a resonance circuit including a capacitance set to be tuned to a power transmission frequency for transmitting the power, and a driving impedance of the antenna coil, wherein the reader or And / or using the Q of the entire communication path including the writer device and the IC card to set the respective Qs of the resonance circuit of the reader / writer device and the resonance circuit of the IC card. Contactless IC card system. 2. The Q of a resonance circuit provided in the IC card is 3
2. The non-contact IC card system according to claim 1, wherein the Q of the resonance circuit provided in the reader and / or writer device is set in a range of 3 to 40. 3. The Q of the entire communication path is calculated so that the impedance of the resonance circuit provided in the IC card and the resonance circuit provided in the reader and / or writer device are substantially equal. The non-contact IC card system according to claim 1 or 2. 4. A non-contact IC card system for transmitting electric power and / or signals between a reader or / and a writer device and an IC card in a non-contact manner, wherein an antenna driving impedance of the reader or / and writer device is provided. Obtaining a desired bandwidth with respect to the transmission speed of the signal from the characteristics of the Q of the entire transmission path derived by setting the impedance substantially equal to the impedance of the IC card from the antenna of the reader or / and writer device. Is calculated, and the calculated Q3 and the reader or / and writer device that maximizes the power transmission efficiency from the reader / writer device to the IC card are maximized.
A non-contact IC card system wherein the reader and / or writer device and the resonance circuit of the IC card are set to Q1 and Q2 by using the relationship between Q1 and Q2 of the IC card. . 5. A non-contact IC card system for transmitting electric power and / or signals between a reader / writer device and an IC card in a non-contact manner, wherein the reader / writer device and the IC card are transmitted. A contactless IC card system, wherein the Q of each of the reader and / or writer device and the IC card is set by using the Q of the entire communication path including: