JP2006146539A - Noncontact ic card reader and/or writer device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To facilitate adjustment of resonance frequency, in a noncontact IC card reader and/or writer device, and suppress the loss in a matching circuit for the adjustment. <P>SOLUTION: For adjusting the slippage of resonance frequency of the reader device 10 to a noncontact IC card 20, the device comprises a separate adjusting coil 14 which is electrically separated from a reader coil 11 and magnetically coupled with the reader coil 11 and the matching circuit 15, and adjustment of impedance in resonance is performed by the turn ratio of the two coils 11 and 14, while the adjustment of the resonance frequency is performed by adjustment of a reactance component in the matching circuit 15 or the like. Therefore, the adjustment of resonance frequency can be performed while adjusting the impedance near the resonance frequency, and the adjustment can be facilitated. Since the matching circuit 15 is not provided on the reader coil 11 side, or no resistance component is needed for the adjustment, the loss in the matching circuit 15 can be minimized. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention performs non-contact communication with non-contact IC cards such as ID cards, management cards, commuter passes, coupon tickets, cash cards, etc. in, for example, entrance / exit management systems, automatic ticket gate systems, electronic money, etc. The present invention relates to a reader and / or writer device that performs at least one of reading and writing of a non-contact IC card.

  An example of a reader / writer device for a non-contact IC card as described above is disclosed in Patent Document 1, for example. The configuration of the reader / writer device 100 is simply shown in FIG. When a radio wave (magnetic flux) transmitted from the reader coil 104 is received, the in-card coil of the non-contact IC card generates an in-card power source, and the IC chip is activated by the power source, and is stored in the IC chip. An ID for uniquely identifying the person is returned from the coil in the card to the reader / writer device. The returned signal is received by the reader coil 104, and the ID is decoded by the radio circuit 102 that modulates and demodulates transmission / reception data and is given to the control unit 101. In this way, the control unit 101 reads the ID in the case of the reader device, and transmits a signal corresponding to the read ID from the reader coil 104 to the non-contact IC card in the case of the writer device to perform writing.

In association with the reader coil 104, a matching circuit 103 is provided. The matching circuit 103 and the matching circuit 103 viewed from the wireless circuit 102 and the reader in order to efficiently transmit radio waves from the reader coil 104 to the space. The reactance in the matching circuit 103 is adjusted so that the resonance frequency of the system including the coil 104 matches the frequency (carrier frequency) used for communication, and impedance matching with the radio circuit 102 is performed.
JP 2004-21484 A

  However, in such a method, there is a problem that the Q including the matching circuit 103 and the reader coil 104 has a high Q, the impedance change near the resonance frequency is steep, and adjustment is difficult. In addition, since the matching circuit 103 is provided on the reader coil 104 side and the impedance adjustment at the time of resonance is performed by changing the resistance component, there is a problem that a loss occurs in the matching circuit 103. .

  An object of the present invention is to provide a reader and / or writer device for a non-contact IC card that can be adjusted easily and can suppress loss in a matching circuit.

  A reader and / or writer device for a non-contact IC card according to the present invention includes a radio circuit unit that modulates and demodulates transmission / reception data, and a reader coil that generates an AC magnetic field for feeding and communicating with the non-contact IC card. In the non-contact IC card reader and / or writer device, the adjustment coil that is formed separately from the reader coil and is magnetically coupled to the reader coil and the matching for adjusting the resonance frequency of the magnetically coupled coil A circuit is included.

  According to the above configuration, the IC chip in which the ID that uniquely identifies the carrier is registered receives the radio wave (magnetic flux) transmitted from the reader and / or writer device and generates the power in the card. In a reader and / or writer device that performs at least one of reading and writing of a non-contact IC card in the form of a carrying card comprising an in-card coil that returns the ID to the reader and / or writer device, Or, when adjusting the deviation of the resonance frequency of the writer device with respect to the non-contact IC card, the reader coil side is not provided with an adjustment configuration, but is electrically separated from the reader coil and magnetically coupled to the reader coil. A separate adjustment coil and matching circuit are provided, and the impedance at resonance is adjusted by the turns ratio of the two coils. The adjustment of the resonance frequency carried by such as adjusting the reactance component in the matching circuit.

  Therefore, the resonance frequency can be adjusted while adjusting the impedance near the resonance frequency, and the adjustment can be easily performed. In addition, since no matching circuit is provided on the reader coil side and no resistance component is required for adjustment, loss in the matching circuit can be minimized.

  Further, the reader and / or writer device of the non-contact IC card of the present invention controls the matching circuit so that the current detection unit for detecting the current value flowing through the reader coil and the detected current value become maximum. It further has a control part.

  According to the above configuration, the current detection unit detects the current value flowing through the reader coil, and the control unit controls the matching circuit so that the current value is maximized based on the detection result. Thus, it is possible to always maintain the state in which the magnetic field radio wave is transmitted from, and to secure more stable communication performance. Further, since it is not necessary to manually adjust the matching circuit, convenience can be improved.

  Furthermore, the reader and / or writer device of the non-contact IC card according to the present invention controls a return loss detector that detects a return loss at the end of the reader coil and the matching circuit so that the return loss is minimized. And a control unit.

  According to the above configuration, the return loss detection unit detects the return loss (reflection of input power) at the reader coil end, and the control unit controls the matching circuit based on the detection result so that the return loss is minimized. Thus, the state in which the magnetic field radio wave is transmitted from the reader coil most efficiently can always be maintained, and more stable communication performance can be ensured. Further, since it is not necessary to manually adjust the matching circuit, convenience can be improved.

  As described above, the reader and / or writer device of the non-contact IC card of the present invention is a reader and / or writer device that performs at least one of reading and writing of a non-contact IC card in the form of a carrying card. In adjusting the resonance frequency deviation of the writer device with respect to the non-contact IC card, the adjustment is not provided on the reader coil side, but is electrically separated from the reader coil, and the reader coil is magnetically A separate adjustment coil and a matching circuit to be coupled are provided. The resonance impedance is adjusted by the turn ratio of the two coils, and the resonance frequency is adjusted by adjusting a reactance component in the matching circuit.

  Therefore, the resonance frequency can be adjusted while adjusting the impedance near the resonance frequency, and the adjustment can be easily performed. In addition, since no matching circuit is provided on the reader coil side and no resistance component is required for adjustment, loss in the matching circuit can be minimized.

[Embodiment 1]
FIG. 1 is a block diagram showing an electrical configuration of a reader device 10 for a non-contact IC card according to an embodiment of the present invention. The present invention can be applied to a contactless IC card having at least one function of a reader device and a writer device, and will be described as a reader device in the following description.

  While the non-contact IC card 20 receives an IC chip 21 in which an ID for uniquely identifying a carrier is registered and a radio wave (magnetic flux) transmitted from the reader device 10, it generates a power in the card, A non-contact IC card in the form of a portable card comprising an in-card coil 22 for returning radio waves (magnetic flux) for returning the ID to the reader device 10 and a resonance capacitor 23 provided in parallel to the in-card coil 22. It is.

  On the other hand, the reader device 10 generates a transmission radio wave (magnetic flux), receives a radio wave (magnetic flux), a reader coil 11, a radio circuit 12 that modulates a transmission signal and a demodulation of the reception signal, and the radio circuit 12 The control unit 13 that controls the entire reader device 10 and the reader coil 11 are electrically separated and magnetically coupled to the reader coil 11. A body adjustment coil 14 and a matching circuit 15 for adjusting the resonance frequency of the reader coil 11 are provided. The reader device 10 may have a function as a writer for writing to the non-contact IC card 20 as necessary. The circuit portion including the reader coil 11 and the radio circuit 12 and the circuit portion including the adjustment coil 14 and the matching circuit 15 constitute an independent circuit.

  The reader coil 11 and the adjustment coil 14 are arranged at positions where they are magnetically coupled to each other, and are in a state like a transformer. For this reason, the impedance value at the time of resonance of the system including the reader coil 11, the adjustment coil 14, and the matching circuit 15 as viewed from the wireless circuit 12 is arbitrarily set by changing the turn ratio of the reader coil 11 and the adjustment coil 14. It becomes possible. Further, by changing the reactance value in the matching circuit 15, it is possible to arbitrarily set the resonance frequency of the system including the reader coil 11, the adjustment coil 14, and the matching circuit 15 as viewed from the radio circuit 12.

  FIG. 2 is a block diagram showing a matching circuit 15a which is a configuration example of the matching circuit 15. As shown in FIG. The matching circuit 15a includes a capacitor 16 arranged in parallel to each other and a switch 17 connected in series to each capacitor 16, and each capacitor 16 constitutes an LC parallel resonance circuit with the adjustment coil 14. To do. The switch 17 is selectively turned on by the control unit 13. In the control unit 13, a list of combinations of switches 17 for realizing a necessary capacitance value is stored in advance.

  Therefore, the capacitance value of the entire matching circuit 15 can be freely changed by the ON / OFF combination of the switches 17. Each capacitor 16 may be formed with a capacitance value equal to each other, or may be formed with a capacitance value having a predetermined weight. In addition, the switch 17 may alternatively be turned on, but a plurality of switches 17 may be turned on at the same time to synthesize capacitance values.

In FIG. 2, five switches 17 and five capacitors 16 are used, and the number of combinations of ON / OFF of the switch 17 is 2 ⁵ = 32. However, the present invention is not limited to this. If the number of switches 17 and capacitors 16 is increased, the number of combinations can be further increased, and finer control is possible.

  On the other hand, FIG. 3 is a block diagram showing a matching circuit 15b which is another configuration example of the matching circuit 15. In FIG. The matching circuit 15b includes the adjustment coil 14 and a variable capacitance diode 18 constituting an LC parallel resonance circuit. The variable capacitance diode 18 is a diode in which the capacitance between the terminals changes depending on the magnitude of the reverse voltage when a reverse voltage is applied to the pn junction, and the control circuit 13 controls the reverse voltage, whereby the matching circuit 15b. Can be varied within a certain range.

  In the reader apparatus 10 configured as described above, the resonance frequency is adjusted, for example, by using a non-contact IC card 20 as an employee ID card already used for settlement in a dining room or the like to newly manage the entrance / exit. As in the case where the reader device 10 is installed for the purpose, for the fine adjustment of the resonance frequency set in the reader device 10 by the manufacturer and the resonance frequency of the contactless IC card 20 already used To be done. The procedure is as follows.

  A non-contact IC card 20 is mounted on a plate-shaped reader coil 11 of the reader device 10 via a magnetically permeable member, and the in-card coil 22 of the non-contact IC card 20 and the reader coil 11 are fixed to each other. Keep in the distance. In this state, the control unit 13 controls the ON / OFF of the switch 17 and the voltage applied to the variable capacitance diode 18 to adjust the capacitance value in the matching circuit 15 and adjust the resonance frequency. At this time, the reader coil 11 and the in-card coil 22 are magnetically coupled, and not only the system including the reader coil 11, the adjustment coil 14 and the matching circuit 15, but also the resonance frequency of the system including the non-contact IC card 20. Will be adjusted. By making the resonance frequency coincide with the frequency used for communication (carrier frequency), when the non-contact IC card 20 is arranged at a position where communication is actually performed, radio waves are transmitted from the reader coil 11 most efficiently, More stable communication performance can be ensured.

  As described above, in the reader device 10 that reads the non-contact IC card 20, in adjusting the deviation of the resonance frequency of the reader device 10 with respect to the non-contact IC card 20, it is electrically separated from the reader coil 11. A separate adjustment coil 14 and a matching circuit 15 that are magnetically coupled to the reader coil 11 are provided, and the impedance near the resonance frequency is adjusted by the turn ratio of the two coils 11 and 14, and the reactance value of the matching circuit 15 is Adjustment can be easily performed by adjusting the resonance frequency. Further, the matching circuit 15 is not provided on the reader coil 11 side, and no resistance component is provided in the matching circuit 15, so that loss can be reduced.

[Embodiment 2]
FIG. 4 is a block diagram showing an electrical configuration of a reader device 30 of a non-contact IC card according to another embodiment of the present invention. The reader device 30 is similar to the reader device 10 described above, and corresponding portions are denoted by the same reference numerals and description thereof is omitted. It should be noted that the reader device 30 is provided with a current detection unit 31 that detects a current value flowing through the reader coil 11, and in response to the detection result, the control unit 13 ′ has a maximum current value. The capacitance value of the matching circuit 15 ′ is automatically changed to keep the matching between the radio circuit 12 and the reader coil 11 optimal.

  FIG. 5 is a block diagram showing a current detection unit 31 a which is a configuration example of the current detection unit 31. The current detection unit 31a includes a directional coupler 32, a detection circuit 33, an analog / digital converter 34, and a microcomputer 35. A part of the current flowing through the reader coil 11 is branched by the directional coupler 32, rectified by the detection circuit 33, converted into a digital value by the analog / digital converter 34, input to the microcomputer 35, and processed. The The current value thus obtained is input to the control unit 13 '. The processing of the microcomputer 35 may be performed by the control unit 13 '.

  With this configuration, it is possible to always keep the state in which radio waves are transmitted from the reader coil 11 most efficiently, and to secure more stable communication performance. Further, since it is not necessary to manually adjust the matching circuit 15, it is possible to improve convenience.

[Embodiment 3]
FIG. 6 is a block diagram showing an electrical configuration of a reader device 40 of a non-contact IC card according to still another embodiment of the present invention. The reader device 40 is similar to the reader device 30 described above. It should be noted that, in the reader device 40, the power input to the reader coil 11 does not actually flow through the reader coil 11 but is reflected at the input end of the reader coil 11 and becomes a loss (return loss). ) Is detected, and in response to the detection result, the control unit 13 ″ automatically changes the capacitance value of the matching circuit 15 ″ so that the return loss is minimized, This is to keep the matching between the radio circuit 12 and the reader coil 11 optimal.

  FIG. 7 is a block diagram showing a return loss detection unit 41a which is a configuration example of the return loss detection unit 41. As shown in FIG. The return loss detection unit 41a includes circulators 42 and 43, a directional coupler 44, a detection circuit 45, an analog / digital converter 46, and a microcomputer 47. The circulators 42 and 43 and the directional coupler 44 form a closed loop, and the current from the radio circuit 12 flows to the reader coil 11 as it is through the circulators 42 and 43. The reflected current returns to the radio circuit 12 through the circulator 43, the directional coupler 44 and the circulator 42.

  At this time, a part of the reflected current is branched by the directional coupler 44, rectified by the detection circuit 45, converted into a digital value by the analog / digital converter 46, input to the microcomputer 47, and processed. The reflected current value thus obtained is input to the control unit 13 ''. Note that the control unit 13 ″ may perform the processing of the microcomputer 47.

  Even with this configuration, the state in which radio waves are transmitted from the reader coil 11 with the highest efficiency can always be maintained, and more stable communication performance can be ensured. Further, since it is not necessary to manually adjust the matching circuit 15, it is possible to improve convenience.

It is a block diagram which shows the electric constitution of the reader apparatus of the non-contact IC card which concerns on one Embodiment of this invention. FIG. 2 is a block diagram illustrating a configuration example of a matching circuit in the reader device illustrated in FIG. 1. It is a block diagram which shows the other structural example of the matching circuit in the reader apparatus shown in FIG. It is a block diagram which shows the electric constitution of the reader apparatus of the non-contact IC card concerning other embodiments of the present invention. FIG. 5 is a block diagram illustrating a configuration example of a current detection unit in the reader device illustrated in FIG. 4. It is a block diagram which shows the electric constitution of the reader apparatus of the non-contact IC card based on the further another form of implementation of this invention. It is a block diagram which shows one structural example of the return loss detection part in the reader apparatus shown in FIG. It is a block diagram which shows one structure of the reader / writer apparatus of the conventional non-contact IC card.

Explanation of symbols

10, 30, 40 Non-contact IC card reader device 11 Reader coil 12 Radio circuit 13, 13 ', 13 "Control unit 14 Adjustment coil 15, 15', 15", 15a, 15b Matching circuit 16 Capacitor 17 Switch 18 Variable capacitance diode 20 Non-contact IC card 21 IC chip 22 In-card coil 23 Resonance capacitor 31, 31a Current detection unit 32, 44 Directional coupler 33, 45 Detection circuit 34, 46 Analog / digital converter 35, 47 Microcomputer 41, 41a Return loss detector 42, 43 Circulator

Claims (3)

In a reader and / or writer device of a non-contact IC card comprising a wireless circuit unit that modulates and demodulates transmission / reception data and a reader coil that generates an AC magnetic field for feeding and communicating with the non-contact IC card.
A reader for a non-contact IC card, which is formed separately from the reader coil, and includes an adjustment coil that is magnetically coupled to the reader coil and a matching circuit for adjusting a resonance frequency of the magnetically coupled coil, and / Or lighter device.   The non-contact IC according to claim 1, further comprising: a current detection unit that detects a current value flowing through the reader coil; and a control unit that controls the matching circuit so that the detected current value is maximized. Card reader and / or writer device.   The non-contact IC according to claim 1, further comprising: a return loss detection unit that detects a return loss at the end of the reader coil; and a control unit that controls the matching circuit so that the return loss is minimized. Card reader and / or writer device.

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