JP2006031473A - Rfid tag - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an RFID tag that can prevent information stored therein from being read without losing convenience. <P>SOLUTION: The tag is arranged such that a resistor 33 is inserted into a loop antenna 20 in series and both ends are short-circuited by a short circuit line 34, thereby changing a reception state from a high reception sensitivity state obtained by short-circuiting both ends of the resistor 33 to a low reception sensitivity state obtained by separating the short circuit line 34 from both ends of the resistor 33 and inserting the resistor 33 in series between the loop antenna 20 and IC circuit part 32. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a non-contact RFID tag that can exchange data with a reader / writer.

In recent years, new information recording media called IC cards are widely available on the market. The IC card is a generic name for cards having a card-like or sheet-like shape such as a credit card, a bank card, a point card, etc., and an IC (Integrated Circuit) incorporated in the card.
In particular, non-contact type IC cards are used in combination with a magnetic card system at many stations as commuter passes and the like used when getting on and off at railway station ticket gates. In addition, since the non-contact type IC card exchanges data with the reader / writer via radio waves, the standardization of the protocol, modulation waveform, and encoding between the reader / writer and the IC card is in progress. . An RFID (Radio Frequency IDentification) tag has a function equivalent to that of the non-contact type IC card.

However, since the non-contact type IC card and RFID tag as described above exchange data with the reader / writer, there is a possibility that information in the IC circuit may be read from a remote location, for example. For this reason, for example, when personal information is written in a non-contact type IC card or RFID tag, how to protect privacy becomes a problem.
As one method for preventing information from being read from a remote place, it is conceivable to reduce the reception sensitivity of a non-contact type IC card or RFID tag.
However, when the reception sensitivity of the RFID tag is lowered, reading of information from a distant place can be prevented, but reading by a regular reader / writer is hindered and its convenience is deteriorated.
For this reason, for example, when sharing an RFID tag used for identifying an article at the time of selling the article and an RFID tag used for storing personal information of the purchaser after the sale, the reception sensitivity is considered in consideration of convenience when selling the article. If an RFID tag having a high price is used, it becomes difficult to protect the privacy of personal information after the sale of the article. On the other hand, when an RFID tag with low reception sensitivity is used from the viewpoint of privacy protection, convenience at the time of selling goods is impaired.
Therefore, the present invention has been made in view of the above-described points, and an object thereof is to provide an RFID tag that can prevent reading of information without impairing convenience.

In order to achieve the above object, the invention according to claim 1 is a non-contact method for receiving and transmitting data from / to the outside by receiving a carrier wave based on a predetermined modulation system via a loop antenna and generating internal power. Type RFID tag, at least a transmission / reception circuit connected to the loop antenna, a control circuit connected to the transmission / reception circuit, and a memory device connected to the control circuit, and the IC circuit unit And a reception sensitivity adjustment means for adjusting the reception sensitivity arranged between the loop antenna and the loop antenna, wherein the reception sensitivity adjustment means is configured to be changeable to a plurality of different reception sensitivities. To do.
According to a second aspect of the present invention, the reception sensitivity adjusting means includes an impedance element inserted in series between the loop antenna and the IC circuit unit, and a connection circuit for connecting both ends of the impedance element. It is characterized by that.
The invention according to claim 3 is a non-contact type RFID tag that receives and transmits a carrier wave based on a predetermined modulation method via a loop antenna and generates internal power, thereby transferring data to and from the outside. An IC circuit unit including at least a transmission / reception circuit connected to the loop antenna, a control circuit connected to the transmission / reception circuit, and a memory device connected to the control circuit; and the IC circuit unit and the loop antenna. In the meantime, there is provided an intermittent means for intermittently connecting the loop antenna and the IC circuit section.
The invention according to claim 4 is characterized in that the intermittent means is inserted in series between a loop antenna and the IC circuit section.
The invention according to claim 5 is characterized in that the intermittent means is connected in parallel to the loop antenna.

According to the first aspect of the present invention, the reception sensitivity adjusting means can be changed between the first reception state and the second reception state whose reception sensitivity is lower than the first reception state. Thereby, it is possible to prevent the convenience of the RFID tag from being impaired by using it in the first reception state during normal times. Further, when privacy protection is emphasized, the personal information written in the memory device of the RFID tag can be prevented from being read from the outside by being used in the second reception state.
According to the second aspect of the present invention, since the reception sensitivity adjusting means can be formed by the impedance element and the connection circuit connecting both ends thereof, there is also an advantage that it can be realized with almost no cost increase.
According to the third aspect of the present invention, the intermittent means is provided with the intermittent means between the loop antenna and the IC circuit unit, and by this intermittent means, the operation of the RFID tag can be turned on / off, For example, if the loop antenna and the IC circuit are connected by the intermittent means only when reading information with a regular reader / writer, it is possible to prevent personal information of the RFID tag from being read from the outside. Moreover, the deterioration of convenience can be suppressed depending on the form of use.
According to the fourth and fifth aspects of the present invention, the intermittent means is realized by a simple configuration such as being inserted in series between the loop antenna and the IC circuit unit or connected in parallel to the loop antenna. be able to.

Hereinafter, a non-contact type RFID tag as an embodiment of the present invention will be described. Before describing the RFID tag of the present embodiment, the configuration of a general reader / writer and a non-contact type RFID tag And its operation will be described.
FIG. 1 is a block diagram showing a configuration of an RFID tag reader / writer according to an embodiment of the present invention. The RFID tag reader / writer 100 is controlled by a computer (higher-level device) 50 that controls the entire system by exchanging data with an external reader / writer 100. The reader / writer 100 reads the transmission / reception device 1 that controls the communication protocol of data with the external computer 50, the control device 2 that controls the operation of the entire reader / writer 100, and the firmware that records the procedure for operating the control device 2. Memory device 3 for storing data, modulator 4 for modulating data from control device 2 on a carrier wave, input device 5 for inputting an operation command, and display device for displaying information controlled by control device 2 6, a power amplifier 7 that amplifies the command from the modulator 4, a detector demodulator 8 that converts the carrier wave received from the loop antenna 9 into binary data, and a power carrier wave and data for an IC tag (not shown) And a loop antenna 9 for receiving and transmitting the above.
Next, before describing the operation of the reader / writer 100 according to this configuration, the configuration of the paired RFID tags will be described first.
FIG. 2 is a block diagram showing the configuration of the RFID tag according to the embodiment of the present invention. The RFID tag 200 according to this embodiment includes a loop antenna 20 that transmits and receives data using a power carrier wave from the reader / writer 100, and a rectifier that receives the power carrier wave from the loop antenna 20 and rectifies it to convert it into DC power. Smoothing circuit 22, memory device 23 that controls the storage of control firmware and data, modulator 24 that modulates a transmission command from control circuit 26 with a carrier wave, and binary data from the carrier wave data from transmission / reception circuit 21 And a control circuit 26 that controls the overall operation of the RFID tag 200. As modulation methods, there are ASK (Amplitude Shift Keying), PSK (Phase Shift Keying) method, FSK (Frequency Shift Keying) method and the like.

Next, each operation will be described with reference to FIGS. 1 and 2 together. When a power supply (not shown) is turned on, the reader / writer 100 starts an operation according to a program stored in the memory device 3 after the initial operation of the control device 2. First, initialization is performed. Next, in order to supply power to the RFID tag 200, the control device 2 modulates the signal from the power amplifier 7 by performing modulation by the modulator 4 at the time of command transmission and by receiving no modulation when receiving a response from the RFID tag 200. Send. The signal is radiated to the outside from the loop antenna 9 as an electromagnetic wave. Next, when the RFID tag 200 comes close to the reader / writer 100, the loop antenna 20 receives the power supply signal, rectifies the carrier wave by the rectifying / smoothing circuit 22 and converts it into DC power, and all the circuits in the tag. To supply. When power is supplied and the control circuit 26 is driven, control is started in accordance with a program stored in the memory device 23.
Next, the control circuit 26 first demodulates the command from the transmission / reception circuit 21 by the detector 25 and converts it into a binary signal, and analyzes the command. As a result, when it is recognized that it is called, the response is modulated by the modulator 24 and transmitted from the loop antenna 20 via the transmission / reception circuit 21. The reader / writer 100 receives this response with the loop antenna 9, converts it into a binary code with the detector demodulator 8, analyzes it with the control circuit 2, and recognizes that the RFID tag 200 is a tag conforming to the standard. As a result, data is exchanged between the reader / writer 100 and the RFID tag 200 thereafter.

Hereinafter, the non-contact RFID tag according to the present embodiment will be described based on the operation description of the reader / writer 100 and the non-contact RFID tag 200 described above.
First, the RFID tag according to the first embodiment will be described with reference to FIG.
FIG. 3A is a block diagram showing a circuit configuration of the RFID tag according to the first embodiment, and FIG. 3B is a diagram showing a schematic structure of the RFID tag. It should be noted that the same blocks as those in FIG.
As shown in FIG. 3A, the RFID tag 31 according to the first embodiment includes a loop antenna 20 and an IC circuit unit 32. In this case, the IC circuit unit 32 is provided with a circuit unit other than the loop antenna 20 in the circuit configuration of the RFID tag shown in FIG.
Between the loop antenna 20 and the IC circuit unit 32, a resistor 33 as an impedance element is inserted in series as a reception sensitivity adjusting means, and a short circuit wire 34 is connected to both ends of the resistor 33 as a connection circuit. .

As a structure of such an RFID tag 31, for example, as shown in FIG. 3B, an IC circuit section 32, a loop antenna 20, a resistor 33, and a short-circuit line 34 are formed on a substrate 41. A cut line 35 for separating a part of the substrate 41 is provided on the substrate 41, and a short-circuit line 34 is formed on a portion of the substrate that can be cut by the cut line 35. Thus, depending on whether or not a part of the substrate 41 is cut off by the cut line 34, the reception state with high reception sensitivity in which the IC circuit unit 32 and the loop antenna 20 are connected by the short-circuit line 34, and the IC circuit 32 and the loop antenna. 20 is configured to be able to be changed to a plurality of reception states called reception states with low reception sensitivity connected to each other by a resistor 33.
With this configuration, during normal use, for example, when selling goods, the convenience of the RFID tag 31 is impaired by using the resistor 33 in a highly sensitive operating state in which both ends of the resistor 33 are short-circuited by the short-circuit line 34. Can be prevented.
On the other hand, after the consumer purchases the article and writes the personal information of the consumer, if a part of the substrate 41 is cut out by the cutting unit 35 and used, the reception sensitivity in which the resistor 33 is inserted in series with the loop antenna 20 is obtained. Therefore, it is possible to prevent the personal information written in the RFID tag 31 from being read from a remote position from being read from a remote position. This makes it possible to protect privacy.
Further, as in the present embodiment, when the reception sensitivity adjusting means is formed by an impedance element and a connection circuit connecting both ends thereof, it can be realized with almost no cost increase. In the above example, the case where the short-circuit line 34 is connected to both ends of the impedance element 33 has been described as an example. However, it is of course possible to connect a resistor having a small impedance instead of the short-circuit line.

Next, an RFID tag according to the second embodiment will be described with reference to FIG.
FIG. 4A is a block diagram showing a circuit configuration of the RFID tag according to the second embodiment. It should be noted that the same blocks as those in FIG.
The RFID tag 50 shown in FIG. 4A is provided with a switch 51 as an intermittent means between the loop antenna 20 and the IC circuit unit 32. As the switch 51 in this case, for example, as shown in FIG. 4B, when a pressing force is applied from above, the contacts 52 and 53 are connected by the connection plate 54 and become conductive. On the other hand, when the pressing force from above is lost, the connection plate 54 is separated from the contacts 52 and 53 by the elastic force of the portion where the connection plate 54 is attached, and the conduction between the contacts 52 and 53 is released. A switch is conceivable.
As described above, the RFID tag 50 shown in FIG. 4A has a structure in which the IC circuit unit 32 and the loop antenna 20 are connected to operate the RFID tag only when the switch 51 is on. With this configuration, the RFID tag 50 operates only when the user presses the switch 51, for example, so that personal information written on the RFID tag 50 can be read from a remote location without the user's knowledge. Disappears. Further, if the structure is such that the switch 51 can be held while being pressed by some means, it is possible to prevent the convenience of the RFID tag 50 from being impaired during normal use.
In the example shown in FIG. 4A, the switch 51 is connected between the IC circuit unit 32 and the loop antenna 20. However, this is merely an example, and for example, FIG. As shown, the switch 51 can be connected in parallel to the loop antenna 20. In that case, the switch 51 may be opened only when the switch 51 is pressed, and the loop antenna 20 may be connected to the IC circuit unit 32.
The configuration of the reader / writer as the present embodiment described so far is merely an example, and the configuration of the reader / writer of the present invention is not limited to the present embodiment.

The block diagram for demonstrating operation | movement of a reader / writer. The block diagram for demonstrating operation | movement of a non-contact type RFID tag. The figure which showed the structure of the non-contact-type RFID tag which concerns on the 1st Embodiment of this invention. The figure which showed the structure of the non-contact-type RFID tag which concerns on 2nd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Transmission / reception apparatus, 2 Control circuit, 3 Memory apparatus, 4 Modulator, 5 Input apparatus, 6 Display apparatus, 7 Power amplifier, 8, 8a Detection demodulator, 9, 20 Loop antenna, 11 Reader / writer, 12 A / D conversion 13, storage device 31, 50 RFID tag, 32 IC circuit part, 33 resistor, 34 short circuit wire, 35 cutout part, 51 switch, 52, 53 contact point, 54 connection board

Claims (5)

In a non-contact type RFID tag that receives and transmits data with the outside by receiving a carrier wave based on a predetermined modulation method via a loop antenna and generating internal power,
An IC circuit unit including at least a transmission / reception circuit connected to the loop antenna, a control circuit connected to the transmission / reception circuit, and a memory device connected to the control circuit; and the IC circuit unit and the loop antenna. An RFID tag comprising: a receiving sensitivity adjusting means for adjusting a receiving sensitivity disposed between the receiving sensitivity adjusting means, wherein the receiving sensitivity adjusting means can be changed to a plurality of different receiving sensitivities.   2. The reception sensitivity adjusting means includes an impedance element inserted in series between the loop antenna and the IC circuit unit, and a connection circuit for connecting both ends of the impedance element. RFID tag described in 1. In a non-contact type RFID tag that receives and transmits data with the outside by receiving a carrier wave based on a predetermined modulation system via a loop antenna and generating internal power,
An IC circuit unit including at least a transmission / reception circuit connected to the loop antenna, a control circuit connected to the transmission / reception circuit, and a memory device connected to the control circuit; and the IC circuit unit and the loop antenna. An RFID tag comprising an intermittent means for interrupting the connection between the loop antenna and the IC circuit portion.   The RFID tag according to claim 3, wherein the intermittent means is inserted in series between a loop antenna and the IC circuit section.   The RFID tag according to claim 3, wherein the intermittent means is connected in parallel to a loop antenna.

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