JP2007199871A - Non-contact ic card reader device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reader device for supplying a sufficient power to a plurality of IC cards equipped with different communication systems, and for achieving satisfactory communication. <P>SOLUTION: A control circuit 1,310A transmits a switching instruction with a prescribed time interval to a resistance control part 5,700. The resistance control part 5,700 switches resistance elements 5,300, 5,400, 5,500 and 5,600. Thus, a band width can be changed by the above, and a plurality of different communication systems and satisfactory communication can be achieved. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a reader device that can perform good communication with a plurality of IC cards having different communication methods.

In recent years, the use of non-contact IC cards has been advanced in the fields of security systems, electronic money, etc., and the demand for a reader device that can cope with a single unit even in a situation where a plurality of different communication methods coexist as the use proceeds has increased. .
In Patent Document 1, a reader device sets a low output for an IC card that uses a common bandwidth between a reader device and a plurality of IC cards and has a communication method with a large modulation degree. Discloses a technique for setting an output high for an IC card having a small communication method. Thus, one reader device can communicate with a plurality of IC cards having different communication methods.
JP 2003-18043 A

According to the prior art disclosed in Patent Document 1, communication is possible between a reader device and a plurality of IC cards using a common bandwidth, but there are different bandwidths among a plurality of communication methods. Some have
In order to communicate with a plurality of IC cards having different bandwidths, it is assumed that the reader device has a bandwidth set wider than the bandwidth of the plurality of IC cards. Although it is possible to receive radio waves from the card, there is a problem that sufficient power cannot be supplied to an IC card that requires a sufficiently high magnetic field strength for its activation. Conversely, assuming that the reader device has a bandwidth that is set narrower than the bandwidth of a plurality of IC cards, only a part of the radio waves transmitted from the IC card can be received, and good communication can be achieved. There is a problem that it is not possible.

  In order to solve the above problems, the present invention provides a reader device that enables satisfactory communication while supplying sufficient power to a plurality of IC cards having different communication methods. Objective.

  In order to achieve the above object, the present invention provides a non-contact IC card reader device that performs non-contact communication with two or more non-contact cards each having a different communication method, and has a preset first Q value. And an antenna unit having a second Q value, and a control unit for switching the first and second Q values at respective time intervals.

According to this configuration, since the control unit switches the first and second Q values at respective time intervals, the communication partner device having a bandwidth corresponding to each of the first and second Q values. Good communication is possible in the corresponding time interval.
Here, the antenna unit has the first Q value lower than a predetermined value for a wideband communication scheme, and the second Q value higher than the predetermined value for a narrowband communication scheme. You may have.

According to this configuration, it is possible to perform good communication with a plurality of communication counterpart devices having a wide band and a narrow band. Further, waveform distortion can be suppressed during broadband communication, and communication efficiency can be increased during narrowband communication.
Here, the antenna unit includes an antenna coil, a resistor connected in series to the antenna coil, having a resistance value determined from the first Q value and a resistance value determined from the second Q value, and the control The control unit may include a selection unit that selects one of the two resistance values.

According to this configuration, the Q value of the antenna unit can be switched by increasing or decreasing the resistance value of the resistor.
The antenna unit includes an antenna coil and a diode connected in series with the antenna coil and having a resistance value determined from the first Q value and a resistance value determined from the second Q value, The first and second Q values may be switched by increasing or decreasing the current flowing through the diode.

  According to this configuration, the Q value of the antenna unit can be continuously switched by increasing or decreasing the forward current flowing through the diode.

1. Security system 1000
A security system 1000 as a first embodiment according to the present invention will be described.
(Configuration of security system 1000)
As shown in FIG. 1, the security system 1000 includes a central monitoring device 1100, control units 1200A and 1200B, reader / writer devices 1300A and 1300B, entrance / exit doors 1500A and 1500B, and different communication methods a, b, c, and d. IC cards 1400a, 1400b, 1400c, and 1400d are used.

  Central monitoring apparatus 1100 is connected to control units 1200A and 1200B via communication networks 10 and 20, respectively. The control unit 1200A is connected to the card / reader 1300A and the entrance / exit door 1500A via signal lines 30 and 40, respectively. Similarly, the control unit 1200B is connected to the reader / writer device 1300B and the entrance / exit door 1500B via signal lines 50 and 60, respectively.

IC card 1400a, 1400b, 1400c and 1400d are assigned card identification numbers for distinguishing each other.
The central monitoring device 1100 stores card identification numbers assigned to the IC cards 1400a to 1400d, and the control unit 1200A performs transmission / reception control and status monitoring of the reader / writer device 1300A, and status monitoring of the entrance / exit door 1500A. Controls locking and unlocking. When the user brings the IC card 1400a closer to the reader / writer apparatus 1300A, the IC card 1400a returns the stored card identification number in response to the card identification number return request from the reader / writer apparatus 1300A. The same applies to 1400b to 1400d.

  Next, the reader / writer device 1300A sends the card identification number received from the IC card 1400a to the central monitoring device 1100 through the control unit 1200A, and the central monitoring device 1100 stores the stored card identification number and the received card identification number. And the control unit 1200A issues an unlock command to the control unit 1200A, and the control unit 1200A receiving the unlock command unlocks the entrance / exit door 1500A. If the card identification numbers do not match, they remain locked.

The control unit 1200B performs transmission / reception control and status monitoring of the reader / writer device 1300B, status monitoring and unlocking control of the entrance / exit door 1500B, and communicates with the IC cards 1400a to 1400d in the same manner as the control unit 1200A. Do.
(Circuit configuration of IC card 1400a)
Here, the circuit configuration of the IC card 1400a will be described.

As shown in FIG. 2, the IC card 1400a includes a control circuit 1410a, a storage circuit 1420a, a modulation circuit 1430a, a demodulation circuit 1440a, a power generation circuit 1450a, and an antenna unit 1460a.
The control circuit 1410a is connected to the storage circuit 1420a, the demodulation circuit 1440a, and the modulation circuit 1430a. The demodulation circuit 1440a is connected to the control circuit 1410a and the antenna 1460a. The modulation circuit 1430a is connected to the control circuit 1410a and the antenna 1460a. The power generation circuit 1450a is connected to the demodulation circuit 1440a, the modulation circuit 1430a, the control circuit 1410a, and the storage circuit 1420a.

The power generation circuit 1450a generates power to be used inside the IC card 1400a and supplies power to the demodulation circuit 1440a, the modulation circuit 1430a, the control circuit 1410a, and the storage circuit 1420a.
The demodulation circuit 1440a demodulates and extracts a signal from the transmission wave, and sends the signal to the control circuit 1410a.

The memory circuit 1420a stores a card identification number unique to the IC card 1400a.
The control circuit 1410a decodes the received signal to extract information from the reader / reader device, determines whether the extracted information is a card identification number read instruction or another instruction, and determines the card identification. In the case of a number reading instruction, the card identification number is read from the storage circuit 1420a, and a response signal is generated by NRZ encoding the read card identification number and sent to the modulation circuit 1430a.

The modulation circuit 1430a modulates the non-modulation section of the carrier wave transmitted from the reader / writer device with the response signal sent from the control circuit 1410a.
The antenna unit 1460 transmits and receives a reply wave and a transmission wave.
Similarly, the control circuit 1410b of the IC card 1400b performs RZ encoding on the card identification number extracted from the storage circuit 1420b, and the control circuit 1420c of the IC card 1400c converts the card identification number extracted from the storage circuit 1420c to Manchester. The control circuit 1410d of the IC card 1400d performs encoding on the card identification number extracted from the storage circuit 1420d, and the modulation circuit 1430d generates a subcarrier.
(Q value and bandwidth)
Here, the Q value, resonance frequency, and bandwidth used in the following will be described.

A frequency characteristic curve is a curve representing the relationship between a frequency and the current possessed by that frequency, with the vertical axis representing current and the horizontal axis representing frequency.
The Q value is defined by Q = (ωL) / R, and is a numerical value representing the sharpness of the resonance frequency characteristic curve. ω is an angular frequency, L is a reactance value, and R is a resistance value.
The higher the Q value, the stronger the magnetic field strength of the antenna unit 1360A, so that the communicable distance with the IC card becomes longer and the IC card can generate higher power.

The bandwidth represents the width of the frequency that can be received simultaneously by the antenna unit 1360A, and the wider the width, the wider the frequency can be received simultaneously.
The Q value and the bandwidth have a relationship that the bandwidth decreases as the Q value increases, and the bandwidth increases as the Q value decreases.
The Q value is expressed by an explicit function (Q = ωL / R) of the resistance value, and the correspondence between the Q value and the resistance value is clear, so it is used as a standard for changing the bandwidth.
(Reader / writer device 1300A)
<Overall configuration>
A circuit configuration of the reader / writer device 1300A will be described with reference to FIG. Note that the reader / writer device 1300B is the same as the reader / writer device 1300A, and a description thereof will be omitted.

As shown in FIG. 2, the reader / writer device 1300A includes a clock circuit 1305A, a control circuit 1310A, a modulation circuit 1320A, an RF transmission circuit 1330A, a demodulation circuit 1340A, an RF reception circuit 1350A, and an antenna unit 1360A.
The clock circuit 1305A is connected to the control circuit 1310A. The control circuit 1310A is connected to the modulation circuit 1320A, the demodulation circuit 1340A, the RF transmission circuit 1330A, the RF reception circuit 1350A, and the antenna unit 1360A. The modulation circuit 1320A is connected to the RF transmission circuit 1330A, the RF transmission circuit 1330A is connected to the antenna unit 1360A, the RF transmission circuit 1330A is connected to the antenna unit 1360A, and the demodulation circuit 1340A is The RF receiving circuit 1350A is connected, and the RF receiving circuit 1350A is connected to the antenna unit 1360A.

The clock circuit 1305A sends a switching signal to the control circuit 1310A.
The control circuit 1310A generates a question signal to the IC card and issues a switching command to each circuit.
The modulation circuit 1320A performs modulation for each communication method, and the RF transmission circuit 1330A performs output adjustment for each communication method.
The RF receiving circuit 1350A performs output adjustment and band limitation for each communication method.

The demodulating circuit 1340A demodulates the modulation signal returned from the IC card.
The antenna unit 1360A transmits and receives transmission waves and reply waves.
<Circuit Configuration of Antenna Unit 1360A>
As shown in FIG. 4, the antenna unit 1360A includes a resistance control circuit 5700, an antenna coil 5100, a capacitor 5200, and resistance elements 5300, 5400, 5500, and 5600. The resistance control circuit 5700 includes a switch 5750.

One end of the antenna coil 5100 is connected to the RF receiving circuit 1350A, and the other end is connected to the capacitor 5200.
One ends 5320, 5420, 5520, and 5620 of the resistance elements 5300, 5400, 5500, and 5600 are connected to the capacitor 5200.
Any one of the other ends 5310, 5410, 5510, and 5610 of the resistance elements 5300, 5400, 5500, and 5600 is connected to the switch 5750. One end 5752 of the switch 5750 is connected to the RF transmission circuit 1330A.
<Communication method of security system 1000>
Here, a communication method used in the security system 1000 will be described.

The communication method a is a communication method without NRZ encoding method / load modulation / subcarrier, and the communication method b is a communication method without RZ encoding method / load modulation / subcarrier. The communication method c is a Manchester encoding method / load modulation / no subcarrier communication method, and the communication method d is a Manchester encoding method / load modulation / subcarrier communication method.
The communication method a uses the bandwidth 4100, the communication method b uses the bandwidth 4200, the communication method c uses the bandwidth 4300, and the communication method d uses the bandwidth 4400 during communication.
<Selection of resistance element for each communication method>
Here, with reference to FIG. 3, a description will be given of how to select a resistance element used when communicating with the communication method a.

  Since the IC card 1400a of the communication method a uses the bandwidth 4100 to return to the reader / writer device 1300A, the antenna unit 1360A can create a wider bandwidth than the bandwidth 4100, and the power at resonance If a resistance element with a larger value is selected, the reader / writer device 1300A and the IC card 1400a can perform good communication. Therefore, a resistance element that creates the resonance frequency 4150 and the bandwidth 4100 is selected, and this is designated as the resistance element 5300.

Similarly, the resistance element 5400 is selected when communicating with the communication method b, the resistance element 5500 is selected when communicating with the communication method c, and the resistance element 5600 is selected when communicating with the communication method d.
(Configuration of control circuit 1310A)
<Processing cycle of control circuit 1310A>
As shown in FIG. 5, the control circuit 1310A performs communication with different communication methods a to d by sequentially changing the Q value.

The processing times of the communication methods a to d are different, the processing time of the communication method a is Ta, the processing time of the communication method b is Tb, the processing time of the communication method c is Tc, and the processing time of the communication method d is Td. is there.
The communication method a is processed between Ta in sections 6101 and 6102, the communication method b is processed between Tb in sections 6201 and 6202, the communication method c is processed between Tc in sections 6300 and 6301, and the communication method is used in sections 6400 and 6401. Process d is performed for Td.
<Processing selection of control circuit 1310A>
FIG. 6 is a flowchart showing the communication system switching means processed by the control circuit 1310A that receives the switching signal from the clock circuit 1305A.

The clock circuit 1305A sends a switching signal to the control circuit 1310A (S7100). The control circuit 1310A receives the switching signal from the clock circuit 1305A (S7002).
Next, the value obtained by adding 1 to variable I is put again in variable I (S7003).
The remainder of dividing variable I by 4 is put back into variable I. When I is 1, communication method a processing (S7005), when 2, communication method b processing (S7007), when 3, communication method c (S7008), in the case of 0, the processing of the communication method d (S7009) is performed, and after completion of each processing, a clock signal is waited (S7002).
<Instructions from the control circuit 1310A to each circuit>
FIG. 7 is a flowchart showing the processing inside the circuit and the operation of each circuit in the control circuit 1310A during the processing of the communication method a.

The control circuit 1310A starts processing corresponding to the communication method a.
The control circuit 1310A sends a resistance switching command to the resistance control unit 5700 (S8001), switches the inside of the circuit to a signal generation method corresponding to the communication method a, and generates a question signal to the IC card 1400a (S8002). ). In parallel with this, the control circuit 1310A switches to the modulation circuit 1320A (S8003), switches to the RF transmission circuit 1330A (S8004), switches to the RF reception circuit 1350A (S8009), and switches to the demodulation circuit 1340A (S8010). ) And transmit a transmission wave through the antenna unit 1360A (S8005).

Next, the control circuit 1310A stops generating the interrogation signal to the IC card 1400a in its own circuit (S8006), sends a modulation stop command (S8007) to the modulation circuit 1320A, and transmits only the carrier wave through the antenna unit 1360A (S8008). .
Next, the control circuit 1310A determines whether or not there is a reply from the IC card 1400a (S8011). If there is no reply (NO in S8011), the processing of the communication method a is terminated and there is a reply. In the case (YES in S8011), the card identification number is taken out (S8013), the card identification number is sent to the central monitoring apparatus (S8014), and the process is terminated.

Since the communication methods b, c, and d are the same as the processing of the communication method a, they are omitted here.
<Processing of Control Circuit 1310A and Each Circuit>
FIG. 8 is a diagram showing the processing contents of the control circuit 1310A, the modulation circuit 1320A, the RF transmission circuit 1330A, the RF reception circuit 1340A, the demodulation circuit 1350A, and the resistance control unit 5900 in time series.

FIG. 9 is a diagram showing the operation of the IC card 1400a in time series when receiving a radio wave from the reader / writer device 1300A.
First, the operation of each circuit centering on the control circuit 1310A will be described with reference to FIG.
When the control circuit 1310A receives the switching signal from the clock circuit 1305A (S7100), the control circuit 1310A performs switching 12007 to the signal generation method corresponding to the IC card 1400a in its own circuit, and in parallel with this, the resistance control unit 5900 has a resistance. A switching command 12002 to the element 5300, a switching command 12003 to the modulation method corresponding to the communication method a to the modulation circuit 1320A, a switching command 12004 to an output method corresponding to the communication method a to the RF transmission circuit 1330A, and an RF receiving circuit 1350A An output adjustment and band limitation command 12005 corresponding to the communication method a and a switching command 12006 to the demodulation method corresponding to the communication method a are issued to the demodulation circuit 1340A.

The control circuit 1310A performs question signal generation 12013 to the IC card 1400a between (Ta) / 2, and performs information extraction 12014 from the return signal from the IC card 1400a between the next (Ta) / 2.
When the resistance control circuit 5700 receives the resistance element switching command 12002 corresponding to the communication method “a” from the control circuit 1310A, the resistance control circuit 5700 performs switching 12008, and makes a connection 12015 between Ta and the resistance element 5300.

When the modulation circuit 1320A receives a modulation system switching command 12003 corresponding to the communication system a from the resistance control unit 1310A, the modulation circuit 1320A performs switching 12009 and performs modulation 12017 corresponding to the communication system a on its own circuit. Next, when receiving a modulation stop command 12016 from the control circuit 1310A, the modulation circuit 1320A stops the modulation state corresponding to the communication method a.
When the RF transmission circuit 1330A receives the switching command 12004 corresponding to the communication method a from the control circuit 1310A, the RF transmission circuit 1330A outputs the output 12018 corresponding to the communication method a in its own circuit.
When receiving the switching command 12005 corresponding to the communication method a from the control circuit 1310A, the RF receiving circuit 1350A performs the switching 12011, and performs the output corresponding to the communication method a and the band limitation 12019 within the circuit itself.

When receiving the switching command 12006 from the control circuit 1310A, the demodulating circuit 1340A performs switching 12012, and performs demodulation 12020 corresponding to the communication method a in its own circuit.
The antenna unit 1360A transmits a transmission wave 12041 between the first half (Ta) / 2 and a carrier wave 12042 between the second half (Ta) / 2.
The operation of the IC card 1400a will be described with reference to FIG.

  When the IC card 1400a receives a radio wave corresponding to the communication method a, the power generation circuit 1450a performs power generation 13001 used inside the circuit and supplies power to the control circuit 1410a, the storage circuit 1420a, the modulation circuit 1430a, and the demodulation circuit 1440a. Then, the demodulation circuit 1440a performs demodulation 13002, and the control circuit 1410a decodes the question signal 13003. Further, for the reply of the inquiry signal, the card identification number is extracted from the storage circuit 1420a 13004, the extracted inquiry number is encoded 13005, the modulation is performed by the modulation circuit 1430a, and the transmission 13007 is performed through the antenna 1460a.

Each time the control circuit 1310A receives a switching signal from the clock circuit 1305A, the communication system b, the communication system c, the communication system d, and the processing corresponding to each communication system are sequentially started. Are the same as in the case of the communication method a, except for the operation.
Note that the resistance control unit 5700 according to the present embodiment may use an electronic switch instead of the analog switch.
2. Modification (1)
As a modification of the antenna unit 1360A, an antenna unit 1360Aa will be described.

As shown in FIG. 10, the antenna unit 1360Aa includes an antenna coil 14300, a capacitor 14200, a variable resistance element 14400, and a resistance control unit 14500.
The resistance control unit 14500 includes a tap 14510.
The variable resistor 14400, the capacitor 14200, and the antenna coil 14300 are connected in series.

One end 14560 of the tap 14510 is connected to the RF transmission circuit 1330A, and the one end 14550 is connected to any one of the contacts 14410, 14420, 14430, and 1440 on the variable resistance element 14400 by switching. The antenna coil 14300 is connected to the RF receiving circuit 1350A.
In order to communicate with the IC card 1400a, the control circuit 1310A connects the one end 14550 of the tap 14510 to the resistance control unit 14500 to one point 14440 to the resistance control unit 14500 instead of the switching command to the resistance control unit 5700. Give an order.

In order to communicate with the IC card 1400b, the control circuit 1310A connects the one end 14550 of the tap 14510 to the resistance control unit 14500 to one point 14430 to the resistance control unit 14500 in place of the switching command to the resistance element 5400. Give an order.
In order to communicate with the IC card 1400c, the control circuit 1310A connects the one end 14550 of the tap 14510 to the resistance control unit 14500 to one point 1420 to the resistance control unit 14500 in place of the switching command to the resistance control unit 5700 to the resistance element 5500. Give an order.

In order to communicate with the IC card 1400d, the control circuit 1310A connects the one end 14550 of the tap 14510 to the resistance control unit 14500 to one point 14410 instead of the switching command to the resistance control unit 5700 to the resistance element 5600. Give an order.
The Q value can be changed by changing the resistance value of the variable resistance element with a tap by the antenna unit 1360Ab.

Note that the resistance control unit 14500 may use an electronic switch instead of the analog switch.
3. Modification (2)
As a modification of the antenna unit 1360A, an antenna unit 1360Ab will be described.
As shown in FIG. 11, the antenna unit 1260c includes a capacitor 15100, a resistance control unit 15700, resistance elements 15200, 15300, 15400, and 15500, and an antenna coil 15600.
The resistance control unit 15700 includes switches 15710, 15720, 15730, and 15740.

One ends 15220, 15320, 15420, and 15520 of the resistance elements 15200, 15300, 15400, and 15500 are connected to the antenna coil 15600, respectively. Antenna coil 15600 is connected to RF receiving circuit 1350A.
One end 15210 of the resistor element 15200 is connected to the switch 15710, one end 15310 of the resistor element 15300 is connected to the switch 15720, one end 15410 of the resistor element 15400 is connected to the switch 15730, and one end 15510 of the resistor element 15500 is connected to the switch 15740.

One end 15715 of the switch 15710, one end 15725 of the switch 15720, one end 15735 of the switch 15730, and one end 15745 of the switch 15740 are connected to the capacitor 15100, and the capacitor 15100 is connected to the RF transmission circuit 1330A.
In order to communicate with the IC card 1400a, the control circuit 1310A connects the switch 15710 to the one end 15210 and the switch 15720 to the one end 15310 to the resistance control unit 15700 in place of the switching command to the resistance element 5300. Issue a connect command.

In order to communicate with the IC card 1400b, the control circuit 1310A replaces the resistance control unit 5700 with the resistance element 5300 and the resistance element 5400 with a switch 15710 at one end 15210 and the switch 15720 at one end 15310 instead of the switching command to the resistance element 5400. Issue connection instructions to connect each.
In order to communicate with the IC card 1400c, the control circuit 1310A connects the resistance control unit 5700 to the resistance control unit 15700 instead of the switching command to the resistance element 5500, and connects the switch 15710 to the one end 15210 and the switch 15720 to the one end 15310, respectively. Give an order.

In order to communicate with the IC card 1400d, the control circuit 1310A replaces the resistance control unit 5700 with a switching command to the resistance element 5600, and the resistance control unit 15700 has a resistor switch 15710 at one end 15210 and a switch 15740 at one end 15510. Issue a connection command to connect.
In the antenna unit 1360Ab, the Q value can be changed by changing the resistance value by combining one or more resistance elements.

Note that the resistance control unit 15700 may use an electronic switch instead of the analog switch.
4). Modification (3)
As a modification of the antenna unit 1360A, an antenna unit 1360Ac will be described.
As shown in FIG. 12, the antenna unit 1360Ac includes a variable resistance element 16100, a coil 16200, a capacitor 16300, a capacitor 16400, a PIN diode 16500, a coil 16600, a capacitor 16700, an antenna coil 16800, and a resistance control unit 16900.

The resistance control unit 16900 includes a tap 16950.
The capacitor 6300 and the capacitor 16400 are connected in series. The capacitor 16400 is connected to the anode side of the PIN diode 16500, and the capacitor 16700 is connected to the cathode side of the PIN diode 16500. Capacitor 16700 is connected to antenna coil 16800, and one end of antenna coil 16800 is connected to RF receiving circuit 1350A.

  The variable resistance element 16100 and the antenna coil 16200 are connected in series, and the antenna coil 16200 is connected between the capacitor 16400 and the anode side of the PIN diode. A coil 16600 is connected between the cathode side of the PIN diode 16500 and the capacitor 16700, and the other end is connected to the RF receiving circuit 1350A.

The end point 16900 of the tap 16950 is connected to any one of the contacts 16110, 16100, 16130, and 16140 on the variable resistance element by switching. One end 16970 is connected to the power source, the capacitor 16300 is connected to the RF transmission circuit 1330A, and one end of the antenna coil 16800 is connected to the RF reception circuit 1350A.
In order to communicate with the IC card 1400a, the control circuit 1310A connects the one end 16960 of the tap 16950 to the resistance control unit 16900 to the point 16140 of the variable resistance element 16100 instead of the switching command to the resistance control unit 5700 to the resistance element 5300. Give an order.

In order to communicate with the IC card 1400b, the control circuit 1310A connects the one end 16960 of the tap 16950 to the resistance control unit 16900 to one point 16130 to the resistance control unit 16900 instead of the switching instruction to the resistance control unit 5700. Give an order.
In order to communicate with the IC card 1400c, the control circuit 1310A connects the one end 16960 of the tap 16950 to the resistance control unit 16900 to the point 16120 of the variable resistance element 16100 instead of the switching command to the resistance control unit 5700 to the resistance element 5500. Give an order.

In order to communicate with the IC card 1400d, the control circuit 1310A connects one end 16900 of the tap 16950 to the resistance control unit 16900 to one point 16110 to the resistance control unit 16900 instead of the switching command to the resistance control unit 5700 to the resistance element 5600. Give an order.
In the antenna unit 1360Ac, the Q value can be changed by changing the resistance value by adjusting the current flowing through the PIN diode.

Note that the resistance control unit 16900 may use an electronic switch instead of the analog switch.
5). Summary In the above-described embodiment, a certain first IC card has a communication method with a narrow desired band (low communication speed, no subcarrier used, etc.), and narrow band (high Q value) with priority on transmission efficiency. It is set to become. On the other hand, another second IC card is provided with a communication method (a high communication speed, using a subcarrier, etc.) having a wider desired band than the first IC card, and a wide band (low in communication reliability). Q value).

In the case of the second IC card, the band of the antenna is adjusted wider than that of the first IC card, and good communication without waveform distortion can be performed within the desired band. In the case of the first IC card, the band of the antenna is adjusted to be narrower than that of the second IC card, and the longest reading distance can be realized with high transmission efficiency.
In the modified example (1), a variable resistor is provided in series with the antenna coil, and the resistance value can be changed by switching the switch. When it is desired to increase the antenna Q value, the switch is switched to the side where the resistance value is decreased. When the antenna Q value is decreased, the switch is switched to the side where the resistance value is increased.

In this manner, the antenna band (Q value) can be arbitrarily adjusted, and the antenna band (Q value) can be finely adjusted by increasing the combination of resistance values.
In the modified example (3), the PIN diode is an antenna switch, and can be controlled ON / OFF by an external control signal. Generally, a PIN diode has a characteristic that an internal series resistance is inversely proportional to a current flowing in a forward direction. Therefore, the Q value can be controlled with higher accuracy by controlling the forward current when turning on the antenna switch and continuously adjusting the series resistance of the diode.

By doing so, it becomes possible to continuously adjust the band (Q value) of the antenna arbitrarily.
As described above, the present invention relates to a transmitting means for sending an encoded and modulated carrier wave as an interrogation signal to a responder, a receiving means for demodulating, decoding and receiving a response signal from the responder, and a predetermined communication procedure. The interrogator can identify a plurality of different types of responders while sequentially switching the encoding and modulation method of the transmission / reception circuit, and the response signal includes data such as the identification number held for the question signal from the interrogator The non-contact ID system is composed of a responder that replies as follows, and is characterized in that the Q value of the interrogator antenna is changed in a time-sharing manner for each method of each responder.

Here, the Q value of the interrogator antenna may be set low in the wideband communication system, and the Q value of the interrogator antenna may be set high in the narrowband communication system.
Here, the Q value of the antenna may be adjusted by increasing or decreasing the resistance value connected to the antenna.
Here, the Q value of the antenna may be adjusted by increasing or decreasing the forward current flowing through the diode switch connected to the antenna.

  In the above embodiment, control of locking / unlocking of the entrance / exit door is performed using the IC card and the reader / writer device, but the use of the IC card and the reader / writer device is not limited to this. .

1 is a system diagram showing a configuration of a security system 1000. FIG. It is a figure which shows the circuit structure of the reader / writer apparatus 1300A and the IC card 1400a. It is a figure which shows the bandwidth which the communication system used with the security system 1000 uses at the time of a reply, and the resonant frequency which the antenna part 1360A makes. It is a circuit diagram which shows the structure of the antenna part 1360A. It is a figure which shows the transmission cycle of communication system ad. It is a flowchart which shows the selection operation | movement of a communication system. It is a flowchart which shows the procedure of instruction | indication to each circuit by control circuit 1310A at the time of the process of the communication system a. It is a figure which shows the processing content of each circuit which received the command from control circuit 1310A in time series. It is a figure showing operation | movement of IC card 1400a which received the electromagnetic wave from the reader / writer apparatus 1300A. It is a figure which shows the circuit structure of antenna part 1360Aa as a 1st modification of the antenna part 1360A. It is a figure which shows the circuit structure of antenna part 1360Ab as a 2nd modification of the antenna part 1360A. It is a figure which shows the circuit structure of antenna part 1360Ac as a 3rd modification of the antenna part 1360A.

Explanation of symbols

1000 monitoring system 1100 central monitoring device 1200A control unit 1300B control unit 1300A reader / writer device 1300B reader / writer device 1500A entry / exit door 1500B entry / exit door 1400a IC card 1400b corresponding to communication method a IC card 1400c corresponding to communication method b IC card 1400d corresponding to communication method c IC card 10-60 corresponding to communication method d Signal line 1305A Clock circuit 1310A Control circuit 1320A Modulation circuit 1330A RF transmission circuit 1340A Demodulation circuit 1350A RF reception circuit 1360A Antenna unit 1410a Control circuit 1420a Memory Circuit 1430a Demodulation circuit 1440a Modulation circuit 1450a Power generation circuit

Claims (4)

A reader device that communicates in a contactless manner with two or more cards each having a different communication method,
An antenna unit having a first Q value and a second Q value set in advance;
A non-contact IC card reader device comprising: a control unit that switches the first and second Q values at time intervals determined respectively. The antenna unit has a low first Q value for a broadband communication system,
The non-contact IC card reader device according to claim 1, wherein the second Q value is high with respect to a narrow-band communication method. The antenna unit is
An antenna coil;
A resistor connected in series to the antenna coil, having a resistance value determined from the first Q value and a resistance value determined from the second Q value, and control of the control unit, of the two types of resistance values The contactless IC card reader device according to claim 2, further comprising a selection unit that selects one type. The antenna section includes an antenna coil,
A diode connected in series with the antenna coil and having a resistance value determined from the first Q value and a resistance value determined from the second Q value;
3. The contactless IC card reader device according to claim 2, wherein the first and second Q values are switched by increasing / decreasing a current flowing through the diode.

Images