JP6422336B2 - Reader / writer device - Google Patents

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 avoiding erroneous detection of the RFID medium due to a change in the surrounding environment.

  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, a non-contact type card lock using a non-contact IC card, in which the drive power is supplied only to the card detection means in the standby state, and the non-contact IC card is detected by the card detection means. Japanese Patent Application Laid-Open No. 2004-151867 discloses a technique for saving power by supplying drive power to a communication unit that communicates with an IC card. In the technique disclosed in Patent Document 1, when a card detection signal is periodically output by the card detection means and a response signal having a predetermined value is received with respect to the card detection signal, The contactless IC card is judged to be close.

JP 2005-23734 A

  In the reader / writer device as described above, even when the RFID medium is not close, when the metal is close, the impedance value on the antenna side changes, thereby changing the value of the card detection signal. To do. Therefore, after setting the value of the card detection signal for determining that the RFID medium is close, if an empty can or iron plate is left in the vicinity of the reader / writer device, the card detection signal is Although the value changes and the RFID media is not close to the reader / writer device, it is determined that the RFID media is close, or the RFID media is close to the reader / writer device. There is a risk that the RFID medium may be determined not to be close to each other.

  The present invention has been made in view of the problems of the conventional techniques as described above, and in a reader / writer device that writes and reads information to and from an RFID medium while saving power. An object of the present invention is to provide a reader / writer device capable of avoiding erroneous detection of RFID media due to changes in the surrounding environment.

In order to achieve the above object, the present invention provides:
A detection signal output means for outputting a detection signal for detecting the RFID medium;
Control means for outputting data for communication with the RFID medium;
Transmitting and receiving means for transmitting the detection signal output from the detection signal output means and the communication data output from the control means and modulated, and receiving the received data from the RFID medium for the communication data; Have
The control means is
The detection signal output means is intermittently output at regular intervals to transmit the detection signal intermittently via the transmission / reception means at regular intervals, and the detection signal in the transmission / reception means according to the surrounding environment. A low power consumption mode for detecting the change in the value of the signal;
A normal power mode for outputting the communication data and transmitting the communication data via a transmission / reception unit and performing an operation of receiving the reception data via the transmission / reception unit;
When the value of the signal for detection in the transmission / reception means changes from the value set as a reference value in the low power consumption mode, the mode is shifted to the normal power mode, and the processing in the normal power mode is completed or In a reader / writer device that shifts to the low power consumption mode when reception data for the communication data is not received via the transmission / reception means in the normal power mode,
The control means sets the value of the detection signal in the transmission / reception means as the reference value when starting the operation in the low power consumption mode.

  In the present invention configured as described above, in the low power consumption mode, the detection signal for detecting the RFID medium is intermittently transmitted at regular intervals via the transmission / reception means, and this detection signal transmission / reception means When the value at is changed from the value set as the reference value, it is determined that the RFID medium is approaching, and the mode shifts to the normal power mode. In the normal power mode, communication data is transmitted via the transmission / reception means, and when data received from the RFID medium is received for the communication data, information is written to or read from the RFID medium. After that, when the processing in the normal power mode is completed or when the communication data is transmitted after shifting to the normal power mode, the received data for the communication data is not received via the transmission / reception means. Migrate to In this way, by determining the proximity of the RFID medium in the low power consumption mode in which the detection signal is intermittently transmitted every predetermined time, and then shifting to the normal power mode and performing writing and reading of information on the RFID medium, Power saving is achieved. However, when the ambient environment of the reader / writer device changes due to the proximity of metal or the like to the reader / writer device, the value of the detection signal in the transmission / reception means changes. Therefore, even when the RFID medium is not in proximity to the reader / writer device, the value of the detection signal changes from the value set as the reference value, and the RFID medium is in proximity to the reader / writer device. In spite of the absence, it is determined that the RFID medium is in close proximity, or after that, even if the RFID medium is in proximity to the reader / writer device, it is determined that the RFID medium is not in proximity. There is a fear. Therefore, when the control means starts operation in the low power consumption mode, the value of the detection signal in the transmission / reception means is set as a reference value. As a result, even if the ambient environment of the reader / writer device changes, it is determined that the RFID medium is close by using the detection signal value in the changed ambient environment as a reference value. An erroneous detection of the RFID medium accompanying a change in the environment is avoided.

  According to the present invention, a detection signal for detecting an RFID medium is intermittently transmitted via a transmission / reception unit at regular intervals, and an operation for detecting a change in the value of the detection signal in the transmission / reception unit due to the surrounding environment is performed. A low power consumption mode, and a normal power mode in which communication data is transmitted via the transmission / reception means, and reception data from the RFID medium for the communication data is received via the transmission / reception means. When the value of the detection signal in the transmission / reception means changes from the value set as the reference value in the power consumption mode, it shifts to the normal power mode, and when the processing in the normal power mode is completed or for communication in the normal power mode When the received data for the data is not received via the transmission / reception means, the configuration shifts to the low power consumption mode. Ri, it is possible to achieve power saving. In addition, when the control means starts operating in the low power consumption mode, the value of the detection signal in the transmission / reception means is set as the reference value, so that even if the surrounding environment changes The detection signal value in the surrounding environment is used as a reference value, so that it is determined that the RFID medium is close, so that erroneous detection of the RFID medium accompanying a change in the surrounding environment can be avoided.

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. FIG. 5 is a diagram illustrating a reference value set based on the carrier wave illustrated in FIG. 4, (a) is a diagram illustrating a waveform image based on the reference value, and (b) is a diagram illustrating a phase and an amplitude of the reference value.

  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 and out of contact with an IC card 40 serving as an RFID medium. 12, RF network 13, encoding circuit 19a, oscillator 15, modulator 16, transmission amplifier 14, quadrature detector 20, reception amplifiers 17a and 17b, and A / D converters 18a and 18b And 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, a storage unit 34, and a setting unit 35.

  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 detection signal output means in the present invention, generates a 13.56 MHz signal, and outputs it as a detection 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 setting unit 35 sets the digital values of the I and Q values of the carrier wave in the RF network 13 as reference values when starting the operation in the low power consumption mode described later, and stores them in the storage unit 34.

  The storage unit 34 stores the reference value set by the setting unit 35.

  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.

  The reader / writer device 10 configured as described above has a low power consumption mode and a normal power mode. In the low power consumption mode, the microcomputer 30 intermittently transmits the carrier wave output from the oscillator 15 at regular intervals via the RF network 13 and the antenna coil 11, and the carrier wave in the RF network 13 due to the surrounding environment. An operation for detecting changes in the I value and the Q value is performed. In the normal power mode, the microcomputer 30 transmits communication data for the IC card 40 via the RF network 13 and the antenna coil 11 and receives data received from the IC card 40 for the communication data. . In the normal power mode, 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.

  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 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 the two modes of the low power consumption mode and the normal power mode as described above, and in a state where information is not written to or read from the IC card 40. Operates in the low power consumption mode (step 1).

  When the reader / writer device 10 starts operation in the low power consumption mode, first, a carrier wave is intermittently output from the oscillator 15 at regular intervals, and only the output carrier wave passes through the modulator 16 and the transmission amplifier 14. To the RF network 13 and transmitted through the antenna coil 11 (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.

  When the carrier wave whose I value and Q value are detected by the IQ value detection unit 31 in the setting unit 35 of the microcomputer 30 is a carrier wave that is first intermittently transmitted in the current low power consumption mode ( Step 3), the I value and Q value of the carrier wave detected by the IQ value detection unit 31 are set as reference values for determining whether the IC card 40 is close to the reader / writer device 10; It is stored in the storage unit 34 (step 4). The operation in the setting unit 35 is referred to as calibration.

  Thereafter, in the low power consumption mode, the operation shifts to a card detection operation as to whether or not the IC card 40 is close, and as shown in FIG. 3, a carrier wave is continuously output from the oscillator 15 every predetermined time and output. Only the carrier wave is sent to the RF network 13 via the modulator 16 and the transmission amplifier 14 and is intermittently transmitted via the antenna coil 11 at regular intervals.

  As described above, the carrier wave sent to the RF network 13 is affected by changes in the 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. . The I value and the Q value set as the reference values in the setting unit 35 of the microcomputer 30 can be compared with the I value and the Q value of the carrier wave detected by the IQ value detection unit 31 in the comparison unit 33. The configuration need not be stored in the storage unit 34.

  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, when the operation is started in the low power consumption mode, the I value and Q value of the carrier wave intermittently transmitted through the antenna coil 11 first in the low power consumption mode are digital values. Is detected by the IQ value detection unit 31 and stored in the storage unit 34 as a reference value.

  Therefore, after that, 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 stored as the reference values in the storage unit 34 and detected by the IQ value detection unit 31. When the I value and the Q value change from the I value and the Q value stored as the reference values in the storage unit 34, it can be determined that the IC card 40 is close to the reader / writer device 10.

  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 values in the storage unit 34, and detected by the IQ value detection unit 31. When the I value and the Q value change from the I value and the Q value stored as the reference values in the storage unit 34 and the fact is output from the comparison unit 33 as a comparison result (step 5), the microcomputer 30 controls As a result, the reader / writer device 10 shifts to the normal power mode (step 6), and the data transmission / reception unit 32 starts outputting communication data and outputs an inquiry signal as shown in FIG. Polling starts based on

  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 7).

  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 the received data is decoded by the decoding circuit 19b and is determined to be a response signal from the IC card 40 to the inquiry signal (step 8), a transmission data string to be transmitted to the IC card 40 is a data transmission / reception unit. 32.

  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 9).

  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 wake-up command or the like (step 10). 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.

  After that, when the normal operation process is completed at the host and the reader / writer device 10 is notified of this (step 11), it is determined that the process in the normal power mode has been completed, and the process returns to step 1, and FIG. As shown in FIG. 4, the shift to the low power consumption mode, calibration is executed again, and the I value and Q detected by the IQ value detection unit 31 for the carrier wave first intermittently transmitted in this low power consumption mode. The value is set as the reference value.

  On the other hand, when there is no response to the interrogation signal, changes in the I value and the Q value detected by the IQ value detection unit 31 are not due to the proximity of the IC card 40 to the reader / writer device 10, but the reader / writer It is determined that this is due to a change in the surrounding environment due to the presence of metal or the like in the vicinity of the writer device 10, and the process returns to step 1 to shift to the low power consumption mode, and calibration is executed again. The I value and the Q value detected by the IQ value detection unit 31 for the carrier wave intermittently transmitted first are set as reference values.

  FIG. 5 is a diagram showing a reference value set based on the carrier wave shown in FIG. 4, wherein (a) shows a waveform image based on the reference value, and (b) shows the phase and amplitude of the reference value. FIG.

  As described above, when there is no response to the inquiry signal, the mode shifts to the low power consumption mode, and the I value detected by the IQ value detection unit 31 for the carrier wave first intermittently transmitted in the low power consumption mode and The Q value is set as a reference value, but the I value and Q value set at this time should not change in the surrounding environment before the transition from the normal power mode to the low power consumption mode. Since it is the I value and Q value of the carrier wave in the state where the interrogation signal is transmitted, the IC card 40 is placed in the reader / writer device 10 as shown in FIG. The waveform indicated by the alternate long and short dash line in FIG. 4A as being close to each other is a waveform based on the reference value.

  Then, the I value and Q value based on the amplitude and phase shown in FIG. 4B are set as reference values assuming that the IC card 40 is close to the reader / writer device 10.

  Thereby, in the shifted low power consumption mode, whether or not the IC card 40 is close to the reader / writer device 10 using the I and Q values of the carrier wave in the RF network 13 due to the changed ambient environment as the reference values. As a result, erroneous detection of the IC card 40 is avoided even in an environment where metal or the like is present in the vicinity of the reader / writer device 10.

  As described above, in the reader / writer device 10 of the present embodiment, the carrier wave is intermittently transmitted via the RF network 13 and the antenna coil 11 at regular intervals, and the I value of the carrier wave in the RF network 13 according to the surrounding environment and A low power consumption mode in which an operation for detecting a change in the Q value is performed, and communication data is transmitted through the RF network 13 and the antenna coil 11, and reception data for the communication data is transmitted through the RF network 13 and the antenna coil 11. The normal power mode for performing the receiving operation and when the I value and Q value in the carrier wave RF network 13 change from the values set as the reference values in the low power consumption mode, the mode is shifted to the normal power mode. When the processing in the normal power mode is completed or when the normal power mode is By receiving the data for the inquiry signal at de is configured to shift to the low power consumption mode when not received via the RF network 13 and the antenna coil 11, it is possible to achieve power saving. Further, when the microcomputer 30 starts to operate in the low power consumption mode, the I value and the Q in the RF network 13 of the carrier wave first transmitted through the RF network 13 and the antenna coil 11 in the low power consumption mode. With the configuration in which the value is set as a reference value, the IC card 40 is brought close to each other using the I and Q values of the carrier wave in the RF network 13 in the surrounding environment immediately after starting the operation as the low power consumption mode as the reference values. It will be judged whether or not. As a result, even if the ambient environment of the reader / writer device 10 changes, it is determined whether the IC card 40 is close by using the carrier wave I value and Q value in the changed ambient environment as reference values. Thus, erroneous detection of the IC card 40 due to changes in the surrounding environment can be avoided.

  In this embodiment, when the operation starts in the low power consumption mode, the I value of the carrier wave first transmitted through the RF network 13 and the antenna coil 11 in the low power consumption mode in the RF network 13 and Although the Q value is set as the reference value, the calibration may be executed separately from the low power consumption mode when the operation is started in the low power consumption mode. In such a configuration, the I value and the Q value as the reference values are stored in the storage unit 34, and the I value and the Q value detected by the executed calibration are newly set as the reference values and stored. It is stored in the unit 34. Then, the mode shifts to the low power consumption mode, and the I value and Q value in the RF network 13 of the carrier wave transmitted via the RF network 13 and the antenna coil 11, and the I value and Q stored as the reference values in the storage unit 34. When the values are compared and changes in the I value and the Q value are detected, it is determined that the IC card 40 is close to the reader / writer device 10.

  In the present embodiment, the carrier wave output from the oscillator 15 for transmitting the communication data output from the data transmitting / receiving unit 32 of the microcomputer 30 is used as the detection signal. However, as the detection signal, If the IC card 40 is close to the reader / writer device 10 as long as the values such as the I value and the Q value change in the RF network 13, the carrier wave is not limited.

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 35 Setting unit 40 IC card 41 IC card device

Claims (1)

A detection signal output means for outputting a detection signal for detecting the RFID medium;
Control means for outputting data for communication with the RFID medium;
Transmitting and receiving means for transmitting the detection signal output from the detection signal output means and the communication data output from the control means and modulated, and receiving the received data from the RFID medium for the communication data; Have
The control means is
The detection signal output means intermittently outputs the detection signal at regular time intervals, and the detection signal is intermittently transmitted via the transmission / reception means at regular time intervals, and the detection at the transmission / reception means by the surrounding environment is performed. A low power consumption mode that performs an operation to detect a change in the value of the signal for use,
A normal power mode for outputting the communication data and transmitting the communication data via the transmission / reception means and performing an operation of receiving the reception data via the transmission / reception means;
When the value of the signal for detection in the transmission / reception means changes from the value set as a reference value in the low power consumption mode, the mode is shifted to the normal power mode, and the processing in the normal power mode is completed or In a reader / writer device that shifts to the low power consumption mode when reception data for the communication data is not received via the transmission / reception means in the normal power mode,
The reader / writer device characterized in that the control means sets the value of the detection signal in the transmission / reception means as the reference value when starting the operation in the low power consumption mode.

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