JP4584271B2 - Non-contact IC card reader / writer - Google Patents

Description

  The present invention relates to a non-contact IC card reader / writer for writing and reading information to and from a non-contact IC card.

  In recent years, with the progress of the information-oriented society, information is recorded on a card, and information management and settlement using the card are performed. In information management using such a card, a non-contact IC card equipped with an IC chip capable of writing and reading information in a non-contact state with respect to the card is rapidly used due to its excellent convenience. Is spreading.

  Among them, non-contact IC cards that generate and induce information using 13.56MHz frequency band and are used in various places such as SUICA, Edy, employee ID card, prepaid, etc. Yes. Therefore, there are many people who own a plurality of contactless IC cards by themselves.

  Such a non-contact IC card is used by placing it on a non-contact IC card reader / writer that writes information to or reads information from the non-contact IC card. When a non-contact IC card is put on a non-contact IC card reader / writer, a magnetic field generated by a current flowing through the antenna of the non-contact IC card reader / writer acts on the antenna of the non-contact IC card, thereby Current flows through the antenna, and information is written to or read from the non-contact IC card.

  Therefore, if the non-contact IC card does not exist in the magnetic field generated by the current flowing through the antenna of the non-contact IC card reader / writer, or if the non-contact IC card is not properly distorted with respect to the non-contact IC card reader / writer, Information cannot be written to or read from the contact IC card.

Here, a reader capable of detecting whether or not a non-contact IC card is present in a magnetic field generated by a current flowing through the antenna of the non-contact IC card reader / writer by detecting the amplitude of a carrier wave that generates a magnetic field. A writer is described in Patent Document 1.
JP 2005-235042 A

  As described above, with the spread of non-contact IC cards, there are an increasing number of people who own multiple non-contact IC cards. Often stored in one place. However, even when a plurality of non-contact IC cards are stacked and placed on a non-contact IC card reader / writer, information cannot be written to or read from the non-contact IC card.

  Here, if information cannot be written to or read from the non-contact IC card in the non-contact IC card reader / writer, the reader / writer described in Patent Document 1 described above can be used to When it is possible to detect whether or not the magnetic field generated by the current flowing through the antenna of the non-contact IC card reader / writer is present, and when the non-contact IC card is not properly distorted with respect to the non-contact IC card reader / writer If the non-contact IC card is placed again on the non-contact IC card reader / writer, information can be written to or read from the non-contact IC card.

  However, as described above, when a user touches a non-contact IC card reader / writer with a plurality of non-contact IC cards stacked, the user cannot understand why information cannot be written to or read from the non-contact IC card. In addition, there is a problem in that information cannot be written to or read from the non-contact IC card even if the non-contact IC card is again put on the non-contact IC card reader / writer.

  The present invention has been made in view of the problems of the prior art as described above, and it is possible to determine whether a plurality of non-contact IC cards have been tampered with being overlaid. An object is to provide a contact IC card reader / writer.

In order to achieve the above object, the present invention provides:
An antenna for communication, if the non-contact IC card is held over the antenna, have a non-contact IC line writing and reading of information to the card via the antenna, the contactless IC card is a plurality A non-contact IC card reader / writer in which when power is applied to the antenna in an overlaid state, power supply from the antenna is reduced and information cannot be written to or read from the non-contact IC card;
Level detection means for detecting the output voltage of the antenna;
When the output voltage detected by the level detection means is in a predetermined voltage range set lower than the voltage when one non-contact IC card is trapped by the antenna, the non-contact IC card Control means for determining that the reason that information cannot be written or read is because the antenna is trapped in a state where a plurality of contactless IC cards are stacked,
A notification means for notifying that when it is determined by the control means that a plurality of non-contact IC cards are put on the antenna in a stacked state;
The predetermined voltage range is set by sampling the output voltage detected by the level detection means when being struck by the antenna in a state where a plurality of non-contact IC cards are stacked. IC card reader / writer.

  In the present invention configured as described above, the output voltage of the antenna for writing and reading information to and from the non-contact IC card is detected by the level detection means, and the detected output voltage is one sheet. When the non-contact IC card is in a predetermined voltage range that is set lower than the voltage when the non-contact IC card is placed on the antenna, the control means places the non-contact IC card on the antenna in a state where a plurality of non-contact IC cards are stacked. It is judged that there is, and the fact is notified by the notification means.

  As described above, in the present invention, by adding a few circuits in the non-contact IC card reader / writer, the basic performance of the non-contact IC card reader / writer is not impaired, and an external physical device is not used. It is possible to determine that a plurality of non-contact IC cards have been tampered with being overlaid.

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

  FIG. 1 is a diagram showing an embodiment of a non-contact IC card reader / writer according to the present invention.

  In this embodiment, as shown in FIG. 1, a control unit 101, a transmission circuit 102, a communication antenna 103, a reception circuit 104, a rectifier circuit 105, an A / D converter 106, and a display unit serving as a notification unit. When the non-contact IC card 200 is trapped on the antenna 103, communication with the non-contact IC card 200 is possible via the antenna 103. The rectifier circuit 105 and the A / D converter 106 constitute the level detection means in the present invention.

  The antenna 103 has a coil shape, generates a magnetic field in a direction penetrating the coil-shaped core portion when a current flows, and uses this magnetic field to write / read information to / from the non-contact IC card 200. Is for doing.

  The transmission circuit 102 transmits a signal to be transmitted to the non-contact IC card 200 via the antenna 103.

  The receiving circuit 104 receives a signal transmitted from the non-contact IC card 200 via the antenna 103.

  The rectifier circuit 105 rectifies the output voltage of the antenna 103.

  The A / D converter 106 converts the output voltage of the antenna 103 rectified by the rectifier circuit 105 into a digital value.

  The control unit 101 gives a signal to be transmitted to the non-contact IC card 200 to the transmission circuit 102 and recognizes a signal received from the non-contact IC card 200 by the reception circuit 104. In addition, the output voltage of the antenna 103 converted into a digital value by the A / D converter 106 is used to write information to the non-contact IC card 200 by placing one non-contact IC card 200 on the antenna 103. When the voltage is within a predetermined voltage range set lower than the voltage when reading is performed, it is determined that the antenna 103 is trapped in a state where a plurality of non-contact IC cards are stacked.

  When the control unit 101 determines that the plurality of non-contact IC cards are overlapped and within the communicable range of the antenna 103, the display unit 107 displays a message to that effect.

  The operation of the non-contact IC card reader / writer 100 configured as described above will be described below.

  FIG. 2 is a diagram showing the relationship between the resonance frequency and gain of the non-contact IC card reader / writer 100 and the non-contact IC card 200 shown in FIG.

  As shown in FIG. 2, the non-contact IC card 200 is usually designed and manufactured at a frequency higher than the resonance frequency 13.56 MHz necessary for communication (right side in FIG. 2). It is designed to resonate at 13.56 MHz (center of FIG. 2) when only one antenna 103 is placed on the reader / writer 100.

  Therefore, when the contactless IC card 200 is put on the antenna 103 of the contactless IC card reader / writer 100 in a state where a plurality of contactless IC cards 200 are stacked, the resonance frequency of the contactless IC card 200 becomes the resonance frequency 13. The frequency becomes lower than 56 MHz (left side in FIG. 2), and the power supply at 13.56 MHz becomes small, and communication with the non-contact IC card 200, that is, information cannot be written to or read from the non-contact IC card 200. Become.

  FIG. 3 is a diagram showing the output voltage level of the A / D converter 106 in the non-contact IC card reader / writer 100 shown in FIG.

  The output voltage of the antenna 103 in the non-contact IC card reader / writer 100 shown in FIG. 1 is determined by the resonance state between the antenna 103 and the non-contact IC card 200, and the resonance frequency of the non-contact IC card 200 is non-contact IC card reader / writer. The resonance frequency is 100. The resonance frequency is 13.56 MHz, and is high when the resonance frequency is deviated from 13.56 MHz.

  Therefore, as shown in FIG. 3, the output voltage of the A / D converter 106 is the voltage V1 when the non-contact IC card 200 is not worn by the antenna 103 of the non-contact IC card reader / writer 100, and the non-contact IC card reader. The voltage V2 when one non-contact IC card 200 is put on the antenna 103 of the writer 100 and information is written to or read from the non-contact IC card 200, and the non-contact IC card reader / writer 100. V1 and V3 are lower than V2 when compared with the voltage V3 when a plurality of non-contact IC cards 200 are placed on the antenna 103.

  By using this action, the voltage in the control unit 101 is lower than the voltage when one non-contact IC card 200 is trapped by the antenna 103 and information is written to and read from the non-contact IC card 200. The voltage range is set as a range for determining that the antenna 103 is trapped in a state where a plurality of contactless IC cards 200 are stacked. For example, when a plurality of non-contact IC cards 200 are actually stacked, they are placed on the antenna 103 of the non-contact IC card reader / writer 100, and several output voltages of the A / D converter 106 at that time are sampled. A voltage range is set based on the sampled result.

  In this state, when the non-contact IC card 200 is placed on the antenna 103 of the non-contact IC card reader / writer 100, the output voltage of the antenna 103 is rectified by the rectifier circuit 105, and the rectified output voltage is converted into the A / D converter 106. Is converted to a digital value and provided to the control unit 101.

  In the control unit 101, when the output voltage of the antenna 103 converted into a digital value by the A / D converter 106 is within the set range as described above, a plurality of non-contact IC cards 200 are stacked. In this state, it is determined that the antenna 103 is being deceived.

  After that, the display unit 107 displays that a plurality of non-contact IC cards 200 are overlaid on the antenna 103 in a state where they are stacked. Note that the fact that a plurality of non-contact IC cards 200 are superimposed on the antenna 103 is not limited to display output on the display unit 107, but an alarm output by voice, a patrol light, etc. It is also possible to notify.

  In this way, the user can easily determine that a plurality of non-contact IC cards 200 are stacked and placed on the non-contact IC card reader / writer 100.

It is a figure which shows one Embodiment of the non-contact IC card reader / writer of this invention. It is a figure which shows the relationship between the resonance frequency and gain of the non-contact IC card reader / writer shown in FIG. 1 and a non-contact IC card. It is a figure which shows the output voltage level of the A / D converter in the non-contact IC card reader / writer shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Non-contact IC card reader / writer 101 Control part 102 Transmission circuit 103 Antenna 104 Reception circuit 105 Rectification circuit 106 A / D converter 107 Display part 200 Non-contact IC card

Claims (2)

An antenna for communication, if the non-contact IC card is held over the antenna, have a non-contact IC line writing and reading of information to the card via the antenna, the contactless IC card is a plurality A non-contact IC card reader / writer in which when power is applied to the antenna in an overlaid state, power supply from the antenna is reduced and information cannot be written to or read from the non-contact IC card;
Level detection means for detecting the output voltage of the antenna;
When the output voltage detected by the level detection means is in a predetermined voltage range set lower than the voltage when one non-contact IC card is trapped by the antenna, the non-contact IC card Control means for determining that the reason that information cannot be written or read is because the antenna is trapped in a state where a plurality of contactless IC cards are stacked,
A notification means for notifying that when it is determined by the control means that a plurality of non-contact IC cards are put on the antenna in a stacked state;
The predetermined voltage range is set by sampling the output voltage detected by the level detection means when being struck by the antenna in a state where a plurality of non-contact IC cards are stacked. IC card reader / writer. The contactless IC card reader / writer according to claim 1,
The non-contact IC card reader / writer, wherein the notification means displays and displays that the antenna is being worn by the antenna in a state where a plurality of non-contact IC cards are stacked.

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