JP6825380B2 - RFID system - Google Patents

Description

The present invention relates to a technique for recognizing an RFID (Radio Frequency Identification) tag attached to an article.

In recent years, RFID tags have been used for article management of articles to which RFID tags are attached. In a system that manages goods using RFID tags, a reader / writer antenna that communicates with the RFID tag is placed in the passage used to transport the goods to which the RFID tag is attached, and a carrier (trolley, low-floor hand lifter, etc.) is placed. ), When a plurality of articles are loaded and transported, data is collectively read from each of the RFID tags attached to the plurality of articles by using the antenna of the reader / writer.

However, when a plurality of articles with RFID tags attached are randomly loaded, RFID tags that make it difficult to communicate with the antenna placed in the passage used for transporting the articles are generated, and the reader / writer that transmits radio waves using the antennas. RFID tags attached to each of a plurality of articles may not be recognized at once.

Patent Document 1 discloses a system provided with a reflector that reflects radio waves radiated by a reader / writer antenna as an invention that enables collective recognition of RFID tags attached to each of a plurality of articles. In the system disclosed in Patent Document 1, the main antenna is arranged near the ceiling of the passage of a carrier loaded with an article to which an RFID tag is attached, and a reflector that reflects radio waves radiated by the main antenna is placed beside the passage. By arranging them, a detour route for the radio waves radiated by the main antenna is formed, and the carrier is equipped with an attitude control unit that directs the RFID tag in the direction of reflection of the radio waves on the reflector.

The system disclosed in Patent Document 1 requires a reflector, an attitude control unit, and the like, and has a problem that the system has a large-scale configuration. Patent Document 2 describes a system in which a leaky coaxial cable, which is a cable having an antenna function, is used for an antenna used for wireless communication with an RFID tag as a system capable of accurately reading data from an RFID tag with a simple configuration. It is disclosed.

However, the invention according to Patent Document 1 in which a leaky coaxial cable is used for an antenna used for wireless communication with an RFID tag is not configured so that RFID tags attached to each of a plurality of articles can be collectively recognized.

JP-A-2007-88519 WO2016 / 027686

Therefore, it is an object of the present invention to provide a system in which a leaky coaxial cable is used for an antenna used for wireless communication with an RFID tag, and an RFID tag attached to each of a plurality of articles can be collectively recognized.

The present invention that solves the above-mentioned problems has an RFID tag attached to a plurality of articles, a cable-type antenna in which a plurality of leaky coaxial cables are hung in the shape of a string, and a passage of a carrier that transports the articles. A reader / writer that communicates with the RFID tag using the cable-type antenna provided is provided , and when the carrier passes through the cable-type antenna, the leaky coaxial cable suspended from the center of the cable-type antenna carries the cable. The length of the leaky coaxial cable suspended from the center of the cable-type antenna so as to come into contact with the upper surface of the car should be the shortest, and the length of the leaky coaxial cable should be lengthened toward the end of the hanging position. And, when the carrier passes through the cable antenna, it is suspended from the center of the cable antenna when viewed from the front so that radio waves can be emitted simultaneously from the front of the carrier and the side surface of the carrier. The RFID system is characterized in that the leaky coaxial cable to be lowered is arranged in the back, and the hanging position is arranged so as to be closer to the end .
Contact name in this application also claims the patent for cable antenna required RFID system according to the present invention.

According to the present invention, it is possible to provide a system in which a leaky coaxial cable is used for an antenna used for wireless communication with an RFID tag, and an RFID tag attached to each of a plurality of articles can be collectively recognized.

The figure explaining the structure of the RFID system which concerns on this embodiment. The figure explaining the cable type antenna. The figure explaining the state of LCX when a transport vehicle passes through. The figure explaining the effect of an RFID system. The figure explaining the cable type antenna which concerns on modification 1. The figure explaining the cable type antenna which concerns on modification 2. The figure explaining the reader / writer which concerns on the modification 3.

From here, preferred embodiments of the present invention will be described. The following description does not constrain the technical scope of the present invention, but is described to aid understanding.

FIG. 1 is a diagram illustrating a configuration of an RFID system 1 according to the present embodiment. The RFID system 1 according to the present embodiment uses a leaky coaxial cable (LCX) 30 for an antenna used for wireless communication with the RFID tag 2, and collectively attaches the RFID tags 2 attached to each of a plurality of articles 20. It is a system that was conceived so that it can be recognized.

The RFID system 1 of FIG. 1 includes an RFID tag 2 attached to a plurality of articles 20, a cable-type antenna 3 in which a plurality of LCX30s are suspended in the shape of a string, and an RFID tag 2 using the cable-type antenna 3. The reader / writer 4 is composed of at least a reader / writer 4 that performs wireless communication, and the reader / writer 4 is connected to a server 5 having a function of managing the article 20 using the data stored in the RFID tag 2 via a LAN 5a.

FIG. 2 is a diagram illustrating a cable-type antenna 3. The cable-type antenna 3 according to the present embodiment has a form in which a plurality of LCX30s of the same length (seven in FIG. 2) are suspended in a string-like manner at equal intervals by using a frame 38.

An approach cable 37 for connecting the LCX30 and the reader / writer 4 passes through the inside of the frame 38 for suspending the plurality of LCX30s, and the LCX30 is the approach cable 37 corresponding to the LCX30 by the connector 36 provided at the upper end of the LCX30. Is connected to. The lower end of the LCX30 is not fixed, and a terminating resistor 35 that suppresses signal reflection is provided at the lower end of the LCX30.

The single LCX30 included in the cable-type antenna 3 includes a central conductor 31 that serves as a signal line for a high-frequency signal corresponding to the frequency band of the RFID tag 2, an outer conductor 32 that concentrically surrounds the central conductor 31, and a central conductor 31. It is composed of an insulator 33 that insulates the outer conductor 32 and a sheath 34 that is the outermost side of the LCX30.

For the central conductor 31 of the LCX30, a pipe or a conducting wire (metal wire) made of aluminum or copper is used. A metal foil such as aluminum foil is used for the outer conductor 32 of the LCX30. As the insulator 33 of the LCX30, a pipe made of polyethylene or the like is used. Black polyethylene is used for the sheath 34 of the LCX30. In order to increase the flexibility of the LCX30, the LCX30 of the present embodiment is not provided with a support wire.

In the LCX30 outer conductor 32, a plurality of slots 32a (elongated holes) are formed at regular intervals according to the frequency band of the high frequency signal flowing through the central conductor 31. The slot 32a formed in the outer conductor 32 of the LCX30 is for functioning as an antenna. A part of the energy of the high frequency signal flowing through the central conductor 31 is radiated from the slot 32a as a radio wave, and the RFID is used by using the slot 32a. The signal transmitted by the tag 2 will be received. Since the slots 32a are continuously formed along the longitudinal direction of the LCX30, radio waves corresponding to the frequency band used by the RFID tag 2 can be uniformly radiated along the longitudinal direction of the LCX30.

The distance between the LCX 30s is shorter than the width of the carrier 21. As shown in FIG. 1, even if a plurality of LCX30s are arranged in the width direction of the passage 6 used for transporting the article 20 to which the RFID tag 2 is attached at intervals shorter than the width direction of the transport vehicle 21, the LCX30 can be used. Since it has the property, it is possible for the transport vehicle to pass by squeezing the LCX30.

The reader / writer 4 that communicates with the RFID tag 2 attached to the article 20 to be transported by the carrier 21 is connected to each of the LCX30s suspended from the cable type antenna 3 via the approach cable 37, and transmits radio waves in a predetermined frequency band. It is a device that communicates with the RFID tag 2 by using it. Considering communication with the RFID tag 2 attached to the article 20 transported by the carrier 21, the UHF band has a maximum communication distance of about 5 m as a frequency band used for communication between the reader / writer 4 and the RFID tag 2. It is desirable to use (for example, 860M to 960MHz).

FIG. 3 is a diagram illustrating a state of the LCX 30 when the transport vehicle 21 passes through. By suspending the flexible LCX30 in the shape of a string, when the carrier 21 passes through the LCX30, the LCX30 that comes into contact with the carrier 21 or the article 20 loaded on the carrier 21 is pushed to the left and right. , The LCX30 touches the side surface of the transport vehicle 21, or the LCX30 comes near the luggage to which the RFID tag 2 is attached. Therefore, when the carrier 21 passes through, the LCX30 can radiate radio waves along the longitudinal direction to the side surface of the carrier 21, and is attached to the article 20 (the article 20 stacked in the lower row) that is in the shadow of other luggage. It can communicate with the RFID tag 2.

FIG. 4 is a diagram illustrating the effect of the RFID system 1. FIG. 4A illustrates the state before the transport vehicle 21 reaches the LCX30 suspended in the shape of a string goodwill. Before the transport vehicle 21 reaches the LCX30 suspended in the shape of a string goodwill, the LCX30 suspended in the shape of a string goodwill is substantially perpendicular to the passage 6, and the radio waves radiated by the LCX30 are radiated in front of the transport vehicle 21. Therefore, the reader / writer 4 can communicate with the RFID tag 2b on the front of the carrier 21 by using the LCX30.

FIG. 4B illustrates a state in which the transport vehicle 21 passes through the LCX30 suspended in the shape of a string goodwill. When the carrier 21 passes through the LCX30 suspended in the shape of a string of goodwill, the LCX30 is pushed to the left and right as explained with reference to FIG. 3, and the radio waves radiated by the LCX30 are radiated to the side surface of the carrier 21. Therefore, the reader / writer 4 can communicate with the RFID tag 2a on the side surface of the carrier 21 by using the LCX30.

FIG. 4 (c) illustrates a state immediately after the transport vehicle 21 passes through the LCX 30 suspended in the shape of a string goodwill. When the carrier 21 passes through the LCX30 suspended in the shape of a string goodwill, the LCX30 suspended in the shape of a string goodwill becomes the back surface of the carrier 21, and the radio waves radiated by the LCX30 are radiated to the back surface of the carrier 21. The reader / writer 4 can communicate with the RFID tag 2d on the back surface of the carrier 21 by using the LCX30.

Further, since a part of the radio waves radiated from the front surface of the carrier 21 also reaches the upper surface of the carrier 21, the reader / writer 4 uses the LCX30 to communicate with the RFID tag 2c which is the upper surface of the carrier 21. it can.
In this way, by installing the cable-type antenna 3 in which a plurality of LCX30s are suspended in the shape of a string goodwill in the passage 6 used for transporting the article 20, when the transport vehicle 21 passes through the LCX30 suspended in the shape of a string goodwill. Since the radio waves reach the carrier 21 from various directions in all directions by using the LCX30, the RFID tags 2 attached to each of the plurality of articles 20 can be collectively recognized.

The present invention is not limited to the above-described embodiment, and various modifications can be made.

FIG. 5 is a diagram for explaining the cable type antenna 7 according to the first modification. In the cable-type antenna 3 according to the above-described embodiment, the lengths of the LCX30s suspended in the shape of a string are the same, but in the cable-type antenna 7 according to the first modification, the LCX70 is suspended according to the position where the LCX70 is suspended. The length of is changed. Specifically, the length of the LCX70 suspended from the center of the frame 78 is minimized, and the closer the position where the LCX70 is suspended to the end of the frame 78, the longer the length of the LCX70. Even if the length of each of the LCX70s suspended in the shape of a string goodwill is as shown in FIG. 5, the same effect as that of the above-described embodiment can be obtained. Further, if the length of each of the LCX70s suspended in the shape of a string is as shown in FIG. 5, it is possible to show the driver of the transport vehicle 21 the location through which the plurality of LCX70s suspended in the shape of a string are passed. Since the LCX70 suspended from the center of the cable-type antenna 7 according to the first modification rides on the load loaded on the carrier 21, the reader / writer 4 uses the LCX70 to form an RFID on the upper surface of the carrier 21. It becomes easier to communicate with tag 2.

FIG. 6 is a diagram illustrating the cable type antenna 8 according to the modified example 2. In the cable-type antenna 3 according to the above-described embodiment, the LCX30 is suspended in a straight line, but in the cable-type antenna 8 according to the modification 2, when the cable-type antenna 8 according to the modification 2 is viewed from above. The LCX80 is suspended from the frame 88 so as to form a V shape. Specifically, the LCX80 suspended from the center of the cable-type antenna 8 according to the modified example 2 is arranged at the innermost part when viewed from the front of the cable-type antenna 8 according to the modified example 2, and the position where the LCX30 is suspended is the end. The closer to the portion, the closer to the front of the cable-type antenna 8 according to the second modification when viewed from the front. By arranging a plurality of LCX30s suspended in the shape of a string goodwill as shown in FIG. 6, when the transport vehicle 21 passes through the LCX30 suspended in the shape of a string goodwill, radio waves are simultaneously transmitted from the front surface of the transport vehicle 21 and the side surface of the transport vehicle 21. Can be radiated.

FIG. 7 is a diagram illustrating a reader / writer 9 according to the third modification. As shown in FIGS. 1 and 2, if the LCX30s are arranged at intervals shorter than the width of the carrier 21, the radio waves radiated by the LCX30 may interfere with each other depending on the strength of the radio waves radiated by the LCX30, and the RFID tag You may not be able to communicate with 2. In order to prevent radio wave interference, the reader / writer 9 according to the third modification includes a distributor 90 for selecting and using the LCX30, and for example, the LCX30 is switched and used at predetermined time intervals.

1 RFID system 2 RFID tag 20 Article 21 Carrier 3 Cable type antenna 30 Leakage coaxial cable (LCX)
38 Frame 4 Reader / Writer 7 Cable-type antenna according to Modification 1 70 Leaky coaxial cable (LCX) according to Modification 1.
8 Cable-type antenna according to modification 2 80 Leakage coaxial cable (LCX) according to modification 2
9 Reader / writer according to modification 3

Claims (2)

Using RFID tags attached to each of a plurality of articles, a cable-type antenna in which a plurality of leaky coaxial cables are hung in the shape of a string, and the cable-type antenna provided in the passage of a carrier for transporting the articles. comprising a reader writer to communicate with the RFID tag,
Leakage of the cable-type antenna suspended from the center of the cable-type antenna when the carrier passes through the cable-type antenna. The length of the coaxial cable is made the shortest, the length of the leaky coaxial cable becomes longer as the hanging position becomes the end, and when the carrier passes through the cable type antenna, the front of the carrier. When viewed from the front, the leaky coaxial cable that hangs from the center of the cable-type antenna is placed in the back so that radio waves can be radiated from the side of the carrier at the same time, and the hanging position is closer to the end. It was placed so as to be,
An RFID system characterized by that. It is equipped with a plurality of leaky coaxial cables suspended in the shape of a string of goodwill, and the length of the leaky coaxial cable suspended in the center is shortened to the shortest, and the length of the leaked coaxial cable becomes longer as the suspension position becomes the end. By arranging the leaky coaxial cable that hangs in the center when viewed from the front, and arranging it so that the hanging position is closer to the end.
When a carrier carrying a plurality of articles with RFID tags attached is passed through, the leaky coaxial cable suspended in the center is brought into contact with the upper surface of the carrier, and the front surface of the carrier and the carrier are provided. The radio waves can be emitted from the side of the car at the same time .
A cable-type antenna that features this.

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