JP2005322119A - Device for preventing illegal taking of article equipped with ic tag - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent illegal taking of an article equipped with an IC tag by detecting any communication interference caused by metal or hand. <P>SOLUTION: One side of a gate 1 is used as the transmitting side and the other side as the receiving side and transmitting antennas 2, 3 and receiving antennas 4, 5 are arranged oppositely to each other. A transmitter 6 and a receiver 7 are connected respectively to the transmitting antennas and the receiving antennas. A lamp 8 that displays an alarm is mounted at the top of the gate 1 and the transmitter 6, the receiver 7 and the lamp 8 are integrally connected to one another. The transmitting antenna 2 transmits an ID reading signal to the IC tag 10 attached to the article 9 passing through the gate 1. The receiving antenna 4 receives a response signal from the IC tag 10. The receiving antenna 5 receives an inspection signal transmitted from the transmitting antenna 3. The inspection signal uses a different carrier frequency than the ID reading signal. The frequency band used is divided into a plurality of frequency channels to allow communication in such a way that the frequency of a carrier wave is switched in a time-sharing manner. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an apparatus for preventing unauthorized take-out of articles with an IC tag, which prevents unauthorized take-out of articles with an IC tag by installing a gate with an antenna at an entrance of a warehouse or a store.

Inventory information and entry / exit information in the distribution process from manufacturing to sales by attaching an IC tag that wirelessly exchanges data to and from readers / writers and installing a gate with an antenna at the entrance of a warehouse or store Can be obtained in real time, and illegal take-out of products can be prevented.
An IC tag communicates with a reader / writer using a long wave band of 135 kHz or less, a 13.56 MHz short wave band, a 2.45 GHz microwave band, etc., but if there is a metal between the IC tag and the reader / writer, a magnetic field And radio waves are absorbed by metal, making it difficult to communicate in any band.

If the frequency is 135 kHz or less, the magnetic field may be diffracted through the metal gap, and communication may be possible, but the communication distance becomes extremely short.
In the 13.56 MHz band, the current generated in the metal flows in a direction to cancel the magnetic field of the IC tag, so that the IC tag can hardly obtain an electromotive force.
In the case of the 2.45 GHz band, the antenna is out of tune and communication becomes impossible.
In addition, radio waves in the 2.45 GHz band are well absorbed by water, as used in microwave ovens, and therefore do not pass through the human body.
For this reason, if the IC tag part is covered with a metal such as an aluminum sheet or a hand, communication cannot be performed and the gate can be easily passed.

  The problem to be solved is that communication cannot be performed when the IC tag is covered with a metal or hand, and the present invention is intended to prevent unauthorized take-out of an article with an IC tag by detecting communication interference caused by the metal or hand. It was made for the purpose.

  In the present invention, a first communication means for communication between an antenna installed at a gate and an IC tag passing through the gate, a second communication means for communication between antennas installed at the gate, and the first communication means communicate with each other. The main feature is that it comprises a switching means for switching to the second communication means when the inability is detected, and a notifying means for notifying an alarm when the second communication means detects the inability to communicate after switching. To do.

According to the present invention, when communication between the antenna installed on the gate and the IC tag becomes impossible, the communication is switched to communication between the antennas, so that communication interference caused by metal or hand can be reliably detected.
Further, if the antennas cannot communicate with each other, an alarm is notified, so that it is possible to reliably detect unauthorized take-out of articles with IC tags.

  Hereinafter, embodiments of the present invention will be described.

FIG. 1 is a schematic view of an apparatus for preventing unauthorized take-out of an article with an IC tag according to the present invention.
The unauthorized take-out prevention device is arranged with the transmission antennas 2 and 3 and the reception antennas 4 and 5 facing each other with one side of the gate 1 as the transmission side and the other as the reception side, and the transmitter 6 and the receiver 7 are connected to each. A lamp 8 for displaying an alarm is attached above the gate 1, and the transmitter 6, the receiver 7 and the lamp 8 are connected together.

The transmission antenna 2 transmits an ID read signal to the IC tag 10 attached to the article 9 passing through the gate 1, and the reception antenna 4 receives the response signal from the IC tag 10.
At this time, for example, the ID reading signal and the response signal are modulated by different modulation schemes such as the ASK modulation scheme and the response signal by the FSK modulation scheme, so that the ID reading signal and the response signal can be easily identified.

The transmission antenna 3 transmits an inspection signal for detecting communication interference caused by metal or hands, and the reception antenna 5 receives the inspection signal transmitted from the transmission antenna 3.
The inspection signal uses a carrier frequency different from that of the ID read signal. For example, when the carrier frequency of the ID read signal is set to 13.56 MHz band, a 2.45 GHz band different from that is used.
This makes it easy to detect communication interference by effectively utilizing the characteristics of radio waves that differ depending on the frequency band.
Further, the frequency band to be used is divided into a plurality of frequency channels so that communication can be performed by switching the frequency of the carrier wave in time division.
As a result, the carrier frequency band to be used is widened to avoid a communication failure caused by radio wave interference.
The transmitting antennas 2 and 3 and the receiving antennas 4 and 5 are loop coil antennas in the case of the electromagnetic induction method using the 13.56 MHz band, and printed on the flat plate in the case of the microwave method using the 2.45 GHz band. It becomes a microstrip antenna.

The transmitter 6 and the receiver 7 each have a built-in antenna switching circuit (not shown) to switch between the transmitting antennas 2 and 3 and the receiving antennas 4 and 5, and a frequency synthesizer (not shown) is built into a plurality of frequency channels. The transmission / reception frequency is synthesized and the transmission / reception frequency is switched at regular time intervals.
Also, a synchronization signal is sent from the transmitter 6 to the receiver 7 to synchronize the transmission / reception timing.

FIG. 2 shows a flowchart of an illegal take-out prevention process for an article with an IC tag.
First, in step 101, the transmitter 6 transmits an ID read signal via the transmission antenna 2 at the carrier frequency f0.
Next, in step 102, it is determined whether or not the receiver 7 has received a response signal from the IC tag 10 via the receiving antenna 4. If received, the process returns to step 101 to repeat the transmission of the ID reading signal. .
If not received, in the next step 103, the transmitter 6 transmits the inspection signals in order at the carrier frequencies f1 to fn time-divided via the transmission antenna 3.
Next, in step 104, it is determined whether or not the receiver 7 has received the inspection signals at all the carrier frequencies f1 to fn via the receiving antenna 5, and if received, the process returns to step 101 to return the ID reading signal. Repeat sending.
If not received, the lamp 8 is turned on to notify an alarm in the next step 105, and the process is terminated.

It is the schematic of the unauthorized take-out prevention apparatus of the goods with an IC tag which implemented this invention. It is a flowchart of the illegal taking-out prevention process of an article with an IC tag.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Gate 2, 3 Transmitting antenna 4, 5 Receiving antenna 6 Transmitter 7 Receiver 9 Goods 10 IC tag

Claims (4)

A first communication means for communication between an antenna installed at the gate and an IC tag passing through the gate;
A second communication means for communication between antennas installed at the gate;
Switching means for switching to the second communication means when the first communication means detects that communication is impossible;
An informing means for informing an alarm when the second communication means detects an inability to communicate after switching;
An apparatus for preventing unauthorized take-out of an article with an IC tag, comprising:   The apparatus for preventing unauthorized take-out of an article with an IC tag according to claim 1, wherein communication frequencies of the first communication means and the second communication means are different.   The apparatus for preventing unauthorized take-out of an article with an IC tag according to claim 1, wherein the first communication means and the second communication means synchronize transmission / reception timing during communication. The apparatus for preventing unauthorized take-out of articles with IC tags according to claim 1, wherein the second communication means performs communication by switching a plurality of frequency channels in a time division manner.