JP2011100235A - Rfid tag system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an RFID tag system for reading data from all RFID tags attached to articles even when RFID tags are attached to a large number of articles, and that the articles are moved by a forklift or the like. <P>SOLUTION: An RFID tag system 2 is configured of at least RFID tags 21 attached to articles 20 which are moved by a forklift 26; antennas 23 installed on both sides with respect to the moving direction of the articles 20; a reader/writer 24 connected to each antenna 23; and a pair of reflectors 22. Each of the pair of reflectors 22 is installed with a gap in parallel with the moving direction of the articles 20 so as to face the antennas 23. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a system using an RFID tag capable of contactless communication.

  An article management system using an RFID tag used in RFID (Radio Frequency IDentification) instead of a barcode is being studied. When the RFID tag is used for article management, unlike the case of using a barcode, data can be read from a plurality of RFID tags at a time, so that the article management system can be speeded up and labor-saving.

  When RFID tags are used for article management, it is possible to read data from a plurality of RFID tags at one time. However, depending on the situation when reading data from RFID tags affixed to articles, some contrivance must be applied. For example, data cannot be read from all RFID tags attached to articles.

  For example, if an area where an article with an RFID tag is present is wide, it is impossible to communicate with all RFID tags with one antenna. Therefore, in Patent Document 1, a section for storing an article and a storage in the section are stored. In an article management system provided with an RFID tag attached to an article to be communicated and an antenna that communicates with the RFID tag in a non-contact manner, a plurality of antennas are arranged in the compartment, and the RFID tag In order to determine the position of the article to which the mark is attached, a system is disclosed in which switching means for switching an antenna that performs a communication operation among the plurality of arranged antennas is disclosed.

  On the other hand, in the situation where data is read from an RFID tag at a time while moving a pallet on which a large number of articles attached with RFID tags are stacked with a forklift or the like, the number of articles attached with RFID tags is about several tens. If there is no problem, data could not be read from all RFID tags when the number of articles to which RFID tags were attached became large (for example, 100 or more).

JP 2003-72919 A

  Therefore, the present invention can read data from all RFID tags attached to articles even when the number of articles attached with RFID tags is large and the articles are moved by a forklift or the like. An object is to provide an RFID tag system.

  A first invention for solving the above-mentioned problem is that an RFID tag attached to a moving article, an antenna provided on at least one of the left and right sides with respect to the moving direction of the article, and the antenna are connected. A reader / writer unit and a pair of reflectors, each of the pair of reflectors being spaced in parallel to the moving direction of the article, and one of the reflectors facing the antenna. It is the RFID tag system characterized by being installed in.

  Further, in the second invention, the antenna is provided on both the right and left sides with respect to the moving direction of the article with a predetermined interval in the moving direction of the article, The RFID tag system is installed so as to face the antenna on the opposite side to the moving direction, and the reader / writer unit uses each of the antennas by switching them cyclically.

  Furthermore, a third invention is the RFID tag system according to the second invention, wherein a plurality of the antennas are provided at intervals in the height direction.

  If a pair of reflectors are installed as in the first invention, the radio wave transmitted from the antenna propagates while being repeatedly reflected between the pair of reflectors. Since the pair of reflectors is installed in parallel with the moving direction of the article, the range of the radio wave transmitted by the antenna extends in the moving direction of the article, and the reading range of the RFID tag is expanded in the moving direction of the article. Can do.

  If the reading range of the RFID tag is expanded in the moving direction of the article, the time that the article exists in the reading range of the RFID tag increases and the opportunity to read the RFID tag on the reader / writer unit side increases. Even in a situation where the number is large and the article is moved by a forklift or the like, the data can be read from all the RFID tags attached to the article.

  In addition, if an antenna is provided only on one side with respect to the traveling direction of the article, it becomes difficult for radio waves to reach the article stacked on the opposite side. Therefore, as in the second aspect, antennas are provided on both sides with respect to the traveling direction of the article. It is desirable to provide

  Further, when the articles are stacked high, it is difficult for one antenna to reach the upper and lower articles, so that a plurality of the antennas are provided at intervals in the height direction as in the third invention. It is desirable.

  Thus, according to the present invention described above, even if the number of articles to which RFID tags are affixed is large and the articles are moved by a forklift or the like, all the RFID tags affixed to the articles are used. An RFID tag system capable of reading data can be provided.

The figure explaining the structure of the RFID tag system concerning this invention. 1 is a diagram illustrating a configuration of an RFID system in an embodiment. The figure explaining the article | item in an Example. The figure explaining the mounting state of the articles | goods in an Example. The figure explaining the reflecting plate in an Example. The figure explaining the installation condition of the antenna and reflector in an Example. The figure explaining the condition where the electromagnetic wave transmitted from the antenna propagates. The figure explaining the readable range of the reader-writer unit in an Example. 6A and 6B illustrate an RFID tag reading result in this embodiment.

  From this, the embodiments of the present invention will be described to the extent that those skilled in the art of the present invention can understand the contents of the present invention and implement the present invention.

  FIG. 1 is a diagram for explaining the configuration of an RFID tag system (RFID: Radio Frequency Identification) according to the present invention.

  The RFID tag system 1 shown in FIG. 1 is a system provided for reading data from a plurality of RFID tags 11 attached to an article 10 or the like piled on a pallet carried by a forklift, and the RFID tag system according to the present invention. 1, a pair of reflectors 12 that reflect radio waves transmitted from a reader / writer unit 14 that communicates with the RFID tag 11 are installed for the purpose of expanding the reading range of the antenna 13.

  The RFID tag system 1 is a long range system (communication distance is 1 m or more) using a passive RFID tag 11 operating in the UHF band (860 MHz to 930 MHz) or the microwave frequency band (2.5 GHz or 5.8 GHz). Suitable for

  In a system using the passive RFID tag 11 operating in the UHF band or the microwave frequency band, power is supplied to the RFID tag 11 by radio waves transmitted from the antenna 13 connected to the reader / writer unit 14, and the RFID tag For data transfer from 11 to the reader / writer unit 14, a backscatter method is used.

  In order to improve the reading rate of the RFID tag 11 in a situation where the passive RFID tag 11 operating in the UHF band or the microwave frequency band is moving, the RFID tag 11 exists within the readable range of the antenna 13. Time to do becomes one of the important factors.

  Various methods for extending the time during which the RFID tag 11 exists within the readable range of the antenna 13 are conceivable, but in the RFID system 1 illustrated in FIG. 1, the time during which the RFID tag 11 exists within the readable range of the antenna 13. In order to lengthen the distance, a pair of reflectors 12 that are long in the moving direction of the article 10 are installed so that each of them is spaced in parallel with the moving direction of the article 10 and one of them faces the antenna 13. Yes.

  By installing the pair of reflectors 12 in this manner, radio waves transmitted from the antenna 13 propagate while being repeatedly reflected between the pair of reflectors 12, so that the readable range of the antenna 13 is the movement of the article 10. The time in which the RFID tag 11 exists within the readable range of the antenna 13 becomes longer.

  From here, one Example of this invention is described. FIG. 2 is a diagram illustrating the RFID system 2 in the embodiment. The RFID tag system 2 shown in FIG. 2 is loaded with a plurality (here, 275) of articles 20 (here, containers in a folded state) stacked on a pallet 27 conveyed by a forklift 26. The RFID tag 21 is attached to each article 20.

  As shown in FIG. 2, a pair of reflector plates 22 that are long in the direction of travel of the forklift 26 are provided on both sides of the transport path 28 of the forklift 26 in parallel with the direction of travel of the forklift 26 (here, Each of the poles 29 for mounting the antennas 23 is installed on the side of each reflection plate 22 so as to face the antennas 23 with a width of the conveyance path 28). Two antennas 23 are attached at predetermined intervals in the vertical direction.

  In this embodiment, the passive RFID tag 21 operating in the UHF band is “Scorpion (registered trademark)” manufactured by OMRON, the antenna 23 is V750-HS01CA-JP manufactured by OMRON, and the reader / writer unit 24 is connected. Used OMRON V750-BB50C04-JP each having four antenna ports.

  OMRON V750-BB50C04-JP can be used by cyclically switching a plurality of antennas 23 (here, four) at regular time intervals and connected to the reader / writer unit 24 when reading data from the RFID tab 21 Each of the antennas 23 thus used was cyclically switched.

  A computer 25 in which dedicated software for managing data received from the RFID tag 21 is installed is connected to the reader / writer unit 24, and data received by the reader / writer unit 24 from the RFID tag 21 is received from the reader / writer unit 24. Data transmitted to the computer 25 and received from the RFID tag 21 on the computer 25 side is managed by dedicated software.

  FIG. 3 is a diagram illustrating the article 20 in the embodiment. In this embodiment, the article 20 to which the RFID tag 21 is attached is a folded container, and the dimensions of the article 20 are about 400 mm in width, about 600 mm in depth, and 53 mm in height. A space for accommodating the RFID tag 21 is provided at the corner of the article 20, and the RFID tag 21 having a width of 60 mm and a depth of 100 mm is accommodated in the space.

  FIG. 4 is a diagram for explaining a mounting state of the article 20 in the embodiment. As shown in FIG. 4, in the present embodiment, the articles 20 (here, the containers in a folded state) to which the RFID tag 21 is attached are stacked in 55 stages in a state where five articles are arranged in one stage. Thus, the total number of articles 20 mounted on the pallet 27 is 275.

  FIG. 5 is a diagram illustrating the reflector 22 in the embodiment. As shown in FIG. 5, in this embodiment, the reflector 22 provided on both sides of the conveying path 28 of the forklift 26 has a width of 2,400 mm and a height of 2,800 mm, and one reflector 22 has a width of This is realized by arranging two small reflecting plates 22b in which seven aluminum metal plates 22a having a thickness of 1,200 mm, a height of 400 mm, and a thickness of 0.5 mm are arranged.

  FIG. 6 is a diagram for explaining an installation state of the antenna 23 and the reflection plate 22 in the embodiment. The poles 29 to which the antenna 23 is attached are provided on both sides of the moving direction of the article 20 with a predetermined interval in the moving direction of the article 20, and in this embodiment, the interval between the poles 29 to which the antenna 23 is attached is 2,100 mm. Thus, an antenna 23 is attached to one pole 29 at locations of 1,100 mm and 2,100 mm from the ground of the conveyance path 28 of the forklift 26, respectively.

  If the reflector 22 is installed immediately in front of the antenna 23, radio waves are blocked by the reflector 22. In this embodiment, the reflector is reflected right next to the pole 29 so as not to interfere with the antenna 23 attached to the pole 29. A plate 22 is installed.

  In the present embodiment, the width of the reflecting plate 22 (here, 2,400 mm) is longer than the interval between the poles 29 to which the antenna 23 is attached (here, 2,100 mm). By installing the plate 22, the reflecting plate 22 faces the antenna 23 attached to the pole 29 with the conveyance path 28 of the forklift 26 interposed therebetween.

  Since the distance between the antenna 23 and the RFID tag 21 is also an element related to the reading rate of the RFID tag 11, in this embodiment, each antenna 23 is arranged in consideration of the distance between the antenna 23 and the RFID tag 21. is doing.

  As shown in FIG. 4, the total height of the articles 20 stacked in 55 steps is as high as 3065 mm, which is the height of 2915 mm of the stacked articles 20 plus 150 mm of the pallet. The antenna 23 cannot cover the entire range of the height of the article 20 mounted on the pallet 27. In this embodiment, a predetermined interval (here, 1 m) is opened on one pole 29. By arranging the two antennas 23, the entire range of the height of the article 20 mounted on the pallet 27 is covered.

  Further, if the antenna 23 is provided only on one side in the traveling direction of the transport path 28 of the forklift 26, the distance from the antenna 23 to the article 20 changes on the left and right sides with respect to the traveling direction of the transport path 28 of the forklift 26. In the embodiment, poles 29 are set up on both sides of the conveyance path 28 of the forklift 26, and antennas 23 are installed on both sides of the conveyance path 28 of the forklift 26.

  FIG. 7 is a diagram for explaining a situation in which radio waves transmitted from the antenna 23 propagate. By installing a pair of reflectors 22 having a predetermined length in the moving direction of the article 20 so as to be spaced apart from each other in parallel with the moving direction of the article 20 and facing the antenna 23, respectively. The radio waves transmitted from the two antennas 23 are propagated while being repeatedly reflected between the pair of reflecting plates 22, and the path between the pair of reflecting plates 22 becomes a path for the radio waves.

  FIG. 8 is a diagram illustrating the readable range of the reader / writer unit 24 in the embodiment. In FIG. 8, the solid line range is the reading range of the upper antenna 23, the dotted line range is the reading range of the lower antenna 23, and the readable range of the reader / writer unit 24 is the solid line range and the dotted line range. The added range.

  As shown in FIG. 8, since the pair of reflectors 22 are installed on both sides of the transport path 28 of the forklift 26, the space between the pair of reflectors 22 is on the transport path 28 of the forklift 26. The 24 readable range becomes longer along the conveyance path 28.

  The time for which the RFID tag 21 exists within the readable range of the reader / writer unit 24 is a value obtained by dividing the length L in FIG. 8 by the moving speed of the article. Therefore, a pair of reflectors 22 are installed, and the reader / writer unit If the readable range of 24 is increased along the conveyance path 28, the time during which the RFID tag 21 exists within the readable range of the reader / writer unit 24 becomes longer, and the reading rate of the RFID tag 21 can be increased.

  FIG. 9 is a diagram for explaining the reading result of the RFID tag 21 in the present embodiment. FIG. 9A is a table showing the number of RFID tags 21 from which data is read by the reader / writer unit 24 with the reflector 22 installed, and FIG. 9B shows a state in which the reflector 22 is removed. In the table showing the number of RFID tags 21 from which the reader / writer unit 24 has read data, the output of the reader / writer unit is 890 mW (30 dBm) and the speed of the forklift 26 is 5 km / h.

  As shown in FIG. 9A, in the state where the reflector 22 is installed, the data of all 275 RFID tags 21 attached to the article 20 mounted on the pallet 27 can be read three times. However, as shown in FIG. 9B, when the reflector 22 is removed, the data of all 275 RFID tags 21 attached to the article 20 mounted on the pallet 27 is obtained three times. Neither could be read.

1, 2 RFID tag system 10, 20 Item 11, 21 RFID tag 12, 22 Reflector 13, 23 Antenna 14, 24 Reader / writer unit 25 Computer 26 Forklift 27 Pallet 28 Transport path 29 Pole

Claims (3)

  An RFID tag attached to a moving article, an antenna provided on at least one of left and right with respect to the moving direction of the article, a reader / writer unit connected to the antenna, and a moving direction of the article A pair of reflectors having a predetermined length, each of the pair of reflectors being spaced in parallel to the moving direction of the article, and one of the reflectors facing the antenna RFID tag system, characterized in that it is installed in   The antenna is provided on both sides of the moving direction of the article with a predetermined interval in the moving direction of the article, and each of the pair of reflectors is opposite to the moving direction of the article. 2. The RFID system according to claim 1, wherein the RFID writer unit is installed so as to face the antenna, and the reader / writer unit switches each of the antennas to be used cyclically. The RFID system according to claim 2, wherein a plurality of the antennas are provided at intervals in the height direction.

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