JP2016126423A - Reader/writer device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To save power of a reader/writer device that writes and reads out information in/from an RFID medium.SOLUTION: A reader/writer device intermittently transmits only a carrier wave generated by an oscillator 15 at every constant time interval. A microcomputer 30 determines whether an IC card 40 is in proximity on the basis of a change in the I value and Q value of the carrier wave. If the microcomputer 30 determines that the IC card 40 is in proximity, it transmits communication data, and the reader/writer device transmits and receives data for polling and to the IC card 40.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a reader / writer device for writing and reading information to and from an RFID medium such as a non-contact type IC card, and more particularly to a technique for saving power.

  In recent years, RFID media such as a non-contact type IC card or a non-contact type IC label equipped with an IC capable of reading and writing information in a non-contact state with respect to a card or a label has an excellent convenience. Since then, it is spreading rapidly. When such RFID media is brought close to the reader / writer device, power is supplied from the reader / writer device to read and write information.

  In general, a reader / writer device constantly transmits an inquiry signal to an RFID medium called so-called polling. When a response signal to the inquiry signal is received, the reader / writer apparatus determines that the RFID medium is close to the RFID medium. Send / receive data to / from. For this reason, the constant transmission of the inquiry signal causes power to continue to be consumed even when the RFID medium is not in proximity, which is not preferable in terms of power saving.

  Therefore, in a non-contact communication system consisting of an interrogator and a responder, the interrogator generates a detection radio wave that is weaker than the radio wave for communication with the responder, and by a predetermined change in the radio wave for detection, Japanese Patent Application Laid-Open No. 2004-133867 discloses a technique for transmitting a communication radio wave from an interrogator when the interrogator recognizes that the transponder exists in a range where communication with the interrogator is possible. As in this technology, until the RFID medium is detected in the reader / writer device, the RFID medium is detected using a detection radio wave weaker than the communication radio wave, thereby reducing the reader / writer device. Electricity can be achieved.

JP 2000-49653 A

  However, in the one disclosed in Patent Document 1, the RFID medium is detected using a detection radio wave weaker than the communication radio wave in the reader / writer device until the RFID medium is detected. However, it is hard to say that power is saved because the detection radio wave is always output until the RFID medium is detected.

  The present invention has been made in view of the problems of the prior art as described above, and can achieve power saving in a reader / writer device that writes and reads information to and from an RFID medium. An object of the present invention is to provide a reader / writer device that can be used.

In order to achieve the above object, the present invention provides:
Carrier output means for outputting a carrier wave, control means for outputting communication data for the RFID medium, and modulation means for modulating the carrier wave by placing the communication data output from the control means on the carrier wave Transmitting and receiving means for transmitting the communication data carried on the carrier wave by the modulation means via an antenna unit, and receiving data received from an RFID medium for the communication data via the antenna unit; A reader / writer device that writes and / or reads information to and from the RFID medium by transmitting and receiving the communication data and the received data via the transmitting and receiving unit.
The control means causes the carrier output means to intermittently output the carrier wave at regular intervals and intermittently transmits only the carrier wave via the transmission / reception means and the antenna unit at regular intervals. When the value of the carrier wave is changed from the value set as the reference value due to the change of the impedance of the antenna unit, the output of the communication data is started.

  In the present invention configured as described above, in the control means, only the carrier wave for transmitting the communication data for the RFID medium is intermittently transmitted at regular intervals via the transmission / reception means and the antenna unit. In the means, when the value of the carrier wave changes from the value set as the reference value due to the change of the impedance of the antenna unit, it is determined that the RFID medium is close, the output of communication data is started, and the communication The data for use is carried on the carrier wave and transmitted via the transmission / reception means and the antenna unit. Then, by receiving data received from the RFID medium for communication data, information is written to and read from the RFID medium.

  As described above, whether or not the RFID medium is close is determined by intermittently transmitting only the carrier wave at regular time intervals and using the value of the carrier wave, so the RFID medium is detected until the RFID medium is detected. Power saving can be achieved with respect to a medium in which a signal for detecting a medium is constantly transmitted. At that time, since it is determined whether the RFID medium is close by using a carrier wave for transmitting communication data, it is not necessary to provide a separate configuration for detecting the RFID medium. It is possible to determine whether the RFID medium is close without using the communication data and the received data for the communication data.

  According to the present invention, whether or not the RFID medium is close is determined by intermittently transmitting only the carrier wave at regular intervals, using the value of the carrier wave, and determined that the RFID medium is close. In this case, since transmission / reception of communication data and reception data for the communication data is started, it is possible to save power for a device that constantly transmits a signal for determining that an RFID medium is close. Can do.

It is a block diagram which shows one Embodiment of the reader / writer apparatus of this invention. 3 is a flowchart for explaining the operation of the reader / writer device shown in FIG. 1. 3 is a timing chart for explaining the operation of the reader / writer device shown in FIG. 1. 2A and 2B are diagrams for explaining a change of a carrier wave in the reader / writer apparatus shown in FIG. 1, wherein FIG. 2A is a diagram showing a waveform, and FIG. 2B is a diagram for explaining a method of capturing the change as a digital value. FIG.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram showing an embodiment of a reader / writer device of the present invention.

  As shown in FIG. 1, a reader / writer device 10 according to the present embodiment writes and reads information in a non-contact state with respect to an IC card 40 serving as an RFID medium, and an antenna coil serving as an antenna unit. 11 and the capacitor 12, the RF network 13, the encoding circuit 19a, the oscillator 15, the modulator 16, the transmission amplifier 14, the quadrature detector 20, the reception amplifiers 17a and 17b, and the A / D converter 18a. , 18b, a decoding circuit 19b, and a microcomputer 30.

  The quadrature detector 20 includes mixers 21 a and 21 b and a phase shifter 22. The microcomputer 30 serves as a control means in the present invention, and includes an IQ value detection unit 31, a data transmission / reception unit 32, a comparison unit 33, and a storage unit 34.

  The encoding circuit 19a encodes communication data for an RFID medium including an inquiry signal and a transmission data string output from the microcomputer 30.

  The oscillator 15 serves as a carrier output means in the present invention, and generates and outputs a 13.56 MHz signal.

  The modulator 16 modulates the carrier wave output from the oscillator 15 by placing the communication data encoded by the encoding circuit 19 a on the carrier wave including the signal output from the oscillator 15.

  The transmission amplifier 14 amplifies the carrier wave modulated by the modulator 16 and the carrier wave output from the oscillator 15.

  The RF network 13 serves as a transmission / reception means in the present invention. The RF network 13 transmits the carrier wave amplified by the transmission amplifier 14 via the antenna coil 11 and receives data received from the IC card 40 for communication data. Or received via the antenna coil 11. In the RF network 13, the amplitude and phase of the carrier wave change due to changes in the impedance of the antenna coil 11 and the capacitor 12.

  The antenna coil 11 is connected in parallel with the capacitor 12 and transmits the carrier wave transmitted by the RF network 13 or the communication data carried on the carrier wave by radiating the electromagnetic wave, and receives the electromagnetic wave. By doing so, the reception data from the IC card 40 for the communication data is received.

  The mixer 21 a multiplies the reception data received from the IC card 40 for the communication data received by the RF network 13 by the 13.56 MHz signal output from the oscillator 15, and outputs the communication data from the IC card 40. Output the I component of the received data. Also, the carrier wave extracted from the RF network 13 is multiplied by the 13.56 MHz signal output from the oscillator 15 to output the I component of the carrier wave.

  The phase shifter 22 changes the phase of the 13.56 MHz signal output from the oscillator 15 by 90 °.

  The mixer 21b receives the 13.56 MHz signal output from the oscillator 15 and changed in phase by 90 ° by the phase shifter 22 to the received data from the IC card 40 for the communication data received by the RF network 13. Multiply and output the Q component of the received data from the IC card 40 for the communication data. Further, the carrier wave extracted from the RF network 13 is multiplied by a 13.56 MHz signal output from the oscillator 15 and whose phase is changed by 90 ° by the phase shifter 22 to output the Q component of the carrier wave.

  The reception amplifier 17a amplifies the I component of the reception data from the IC card 40 with respect to the carrier wave and communication data output from the mixer 21a, and removes and outputs the high frequency component.

  The reception amplifier 17b amplifies the Q component of the reception data from the IC card 40 with respect to the carrier wave and communication data output from the mixer 21b, and removes and outputs the high frequency component.

  The A / D converter 18a converts the I component of the carrier wave output from the reception amplifier 17a into a digital value and outputs the digital value.

  The A / D converter 18b converts the Q component of the carrier wave output from the reception amplifier 17b into a digital value and outputs the digital value.

  The decoding circuit 19b decodes the received data from the IC card 40 for the communication data output from the receiving amplifiers 17a and 17b.

  The IQ value detection unit 31 receives the digital values of the I and Q components of the carrier wave output from the A / D converters 18a and 18b, and based on the digital values, the I and Q values of the carrier wave Is detected.

  The storage unit 34 stores the reference values of the carrier wave I value and Q value as digital values. As the reference value, the I value and Q value of the carrier wave when the carrier wave is transmitted through the antenna coil 11 in a state where the IC card 40 is not in proximity to the reader / writer device 10 are detected in advance. The value is set as a reference value and stored in the storage unit 34, details of which will be described later.

  The comparison unit 33 compares the I value and Q value of the carrier wave detected by the IQ value detection unit 31 with the reference value stored in the storage unit 34, and outputs a comparison result.

  The data transmission / reception unit 32 has a comparison result output from the comparison unit 33 in which the I and Q values of the carrier wave detected by the IQ value detection unit 31 are changed from the reference values stored in the storage unit 34. In this case, transmission of communication data is started, an inquiry signal and subsequent transmission data are output, and reception data decoded by the decoding circuit 19b is received.

  In the reader / writer device 10 configured as described above, the microcomputer 30 transmits / receives communication data and reception data via the RF network 13 and the antenna coil 11 to write / read information to / from the IC card 40. Will do.

  The IC card 40 that transmits and receives data to and from the reader / writer device 10 in a non-contact state includes an IC card device 41, an antenna 42, and a capacitor 43.

  The IC card device 41 responds to the inquiry signal transmitted from the reader / writer device 10, and then transmits and receives information via the antenna 42 according to a protocol determined with the reader / writer device 10. .

  Hereinafter, the operation of the above-described reader / writer device 10 will be described.

  FIG. 2 is a flowchart for explaining the operation of the reader / writer device 10 shown in FIG. FIG. 3 is a timing chart for explaining the operation of the reader / writer device 10 shown in FIG.

  The reader / writer device 10 shown in FIG. 1 has two modes, a low power consumption mode and a normal power mode, and has low power consumption when information is not written to or read from the IC card 40. The power mode is set (step 1).

  In the low power consumption mode, as shown in FIG. 3, a carrier wave is intermittently output from the oscillator 15 at regular intervals, and only the output carrier wave is transmitted to the RF network 13 via the modulator 16 and the transmission amplifier 14. And intermittently transmitted through the antenna coil 11 at regular intervals (step 2). The intermittent output of the carrier wave from the oscillator 15 and the intermittent transmission of only the carrier wave may be performed under the control of the microcomputer 30 or may be performed using other control means.

  The carrier wave sent to the RF network 13 is affected by changes in impedance of the antenna coil 11 and the capacitor 12 viewed from the RF network 13, and the amplitude and phase of the carrier wave change in the RF network 13.

  The carrier wave whose amplitude and phase are changed by the RF network 13 due to the influence of the impedance change of the antenna coil 11 and the capacitor 12 is extracted by the quadrature detector 20 as an I component and a Q component. , 17b and the A / D converters 18a, 18b are detected by the IQ value detector 31 of the microcomputer 30 as digital I and Q values.

  Then, the comparison unit 33 of the microcomputer 30 compares the I value and Q value of the carrier wave detected by the IQ value detection unit 31 with the reference value stored in the storage unit 34 and outputs the comparison result. .

  Here, when the IC card 40 is close to the reader / writer device 10 and when it is not close, the impedance values of the antenna coil 11 and the capacitor 12 as viewed from the RF network 13 change, so that RF In the network 13, the amplitude and phase of the carrier wave change.

  4A and 4B are diagrams for explaining the change of the carrier wave in the reader / writer device 10 shown in FIG. 1, wherein FIG. 4A is a diagram showing the waveform, and FIG. 4B is a method of capturing the change as a digital value. It is a figure for demonstrating.

  As shown in FIG. 4A, the carrier wave transmitted from the reader / writer device 10 is generated when the IC card 40 is in proximity to the reader / writer device 10 (illustrated by a one-dot chain line). Are not close to each other (illustrated by a broken line), the phase and amplitude of the waveform in the RF network 13 are different from each other.

  Therefore, as shown in FIG. 4B, the IQ value detector 31 determines whether the IC card 40 is close to the reader / writer device 10 by capturing the change in phase and amplitude as digital values. can do.

  In the reader / writer device 10, the I value and the Q value of the carrier wave transmitted through the antenna coil 11 in a state where the IC card 40 is not in proximity are detected in advance by the IQ value detection unit 31 as digital values. , And stored in the storage unit 34 as a reference value. This reference value is set as the reference value using the I value and Q value detected by the IQ value detection unit 31 for the carrier wave transmitted intermittently first when shifting from the normal power mode to the low power consumption mode. It is conceivable to store it in the storage unit 34. In this case, the I value and the Q value set as the reference values may not be stored in the storage unit 34.

  Thereby, the I value and the Q value detected by the IQ value detection unit 31 are compared with the I value and the Q value set as the reference value and stored in the storage unit 34, and the IQ value detection unit 31 is compared. When the I value and the Q value detected in step 1 change from the I value and the Q value stored as the reference values in the storage unit 34, it is determined that the IC card 40 is close to the reader / writer device 10. Can do.

  In this way, the I value and Q value detected by the IQ value detection unit 31 are compared with the I value and Q value stored as the reference value in the storage unit 34, and the IQ value detection unit 31 detects the value. When the I value and Q value changed from the I value and Q value stored as the reference values in the storage unit 34 and the fact is output as a comparison result from the comparison unit 33 (step 3), the microcomputer 30 As a result of the control, the reader / writer device 10 shifts to the normal power mode (step 4). As shown in FIG. 3, the data transmission / reception unit 32 starts outputting communication data and outputs an inquiry signal. Polling starts based on the protocol.

  The inquiry signal output from the data transmission / reception unit 32 is encoded by the encoding circuit 19a, and is added to the carrier wave output from the oscillator 15 by the modulator 16, whereby the carrier wave is modulated, and the transmission amplifier 15 Then, it is transmitted via the RF network 13 and the antenna coil 11 (step 5).

  Thereafter, when a response signal is transmitted from the IC card 40 to the inquiry signal, the response signal is received as reception data via the antenna coil 11 and the RF network 13. Then, when this received data is decoded by the decoding circuit 19b and determined to be a response signal from the IC card 40 to the inquiry signal (step 6), a transmission data string to be transmitted to the IC card 40 is a data transmission / reception unit. 32.

  If there is no response to the interrogation signal, the reader / writer device 1 returns to step 1, and the reader / writer device 10 shifts to the low power consumption mode under the control of the microcomputer 30 as shown in FIG.

  The transmission data sequence output from the data transmitter / receiver 32 is encoded by the encoding circuit 19a and is added to the carrier wave output from the oscillator 15 by the modulator 16, whereby the carrier wave is modulated, and the transmission amplifier 15, transmitted via the RF network 13 and the antenna coil 11.

  When a reception data string from the IC card 40 for this transmission data string is received via the antenna coil 11 and the RF network 13, the received reception data string is detected by the quadrature detector 20, and a reception amplifier The received data string that is input to the decoding circuit 19b via 17a and 17b and decoded by the decoding circuit 19b is input to the data transmitting / receiving unit 32, and as shown in FIG. 3, the reader / writer device 10 and the IC card 40 Data transmission / reception is performed between the two (step 7).

  The reader / writer device 10 is connected to a host such as a printer device, for example. After the authentication or the like is performed by the ID of the IC card 40 received in the data transmission / reception operation with the IC card 40, the reader / writer device 10 The detection of the IC card 40 is notified by transmitting a wakeup command or the like (step 8). Based on this notification, the host performs normal operation processing such as print output. In FIG. 3, it is described that data transmission / reception is continuously performed between the reader / writer device 10 and the IC card 40 while the host performs normal operation processing. However, as described above, when authentication is performed using the IC card 40 and the host performs normal operation processing, data transmission and reception need only be performed at the start of normal operation.

  Thereafter, when the normal operation process is completed at the host and the reader / writer device 10 is notified of this (step 9), the process returns to step 1 and the reader / writer is controlled by the microcomputer 30 as shown in FIG. The writer device 1 shifts to the low power consumption mode. At this time, in the state where the IC card 40 is not close to the reader / writer device 10, only the carrier wave is transmitted as described above, and the value detected by the IQ value detection unit 31 is newly set as the reference value. May be stored in the storage unit 34.

  As described above, in the reader / writer device 10 according to the present embodiment, whether or not the IC card 40 is close is determined by intermittently transmitting only the carrier wave at regular intervals, and changes in the I value and Q value of this carrier wave. Since the determination is based on this, it is possible to save power with respect to those in which a signal for detecting the IC card 40 is constantly transmitted until the IC card 40 is detected. At that time, it is determined whether or not the IC card 40 is close by using a carrier wave for transmitting communication data, so there is no need to provide a separate configuration for detecting the IC card 40. Further, it is possible to determine whether or not the IC card 40 is close without using the communication data and the reception data corresponding thereto.

DESCRIPTION OF SYMBOLS 10 Reader / writer apparatus 11,42 Antenna coil 12,43 Capacitor 13 RF network 14 Transmission amplifier 15 Oscillator 16 Modulator 17a, 17b Reception amplifier 18a, 18b A / D converter 19a Encoding circuit 19b Decoding circuit 20 Quadrature detector 21a , 21b Mixer 22 Phase shifter 30 Microcomputer 31 IQ value detection unit 32 Data transmission / reception unit 33 Comparison unit 34 Storage unit 40 IC card 41 IC card device

Claims (1)

Carrier output means for outputting a carrier wave, control means for outputting communication data for the RFID medium, and modulation means for modulating the carrier wave by placing the communication data output from the control means on the carrier wave Transmitting and receiving means for transmitting the communication data carried on the carrier wave by the modulation means via an antenna unit, and receiving data received from an RFID medium for the communication data via the antenna unit; A reader / writer device that writes and / or reads information to and from the RFID medium by transmitting and receiving the communication data and the received data via the transmitting and receiving unit.
The control means causes the carrier output means to intermittently output the carrier wave at regular intervals and intermittently transmits only the carrier wave via the transmission / reception means and the antenna unit at regular intervals. The reader / writer device starts output of the communication data when a value of the carrier wave is changed from a value set as a reference value due to a change in impedance of the antenna unit.

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