JP2009124549A - Antenna for reader-writer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antenna for a reader-writer for which a communicable range with an RFID tag attached to merchandise on a merchandise shelf can be easily set according to the position of the RFID tag. <P>SOLUTION: The antenna for the reader-writer has a pair of first conductors 110a provided so as to face each other along the front-to-back direction of the merchandise shelf 11 and a set of second conductors (connection part 110b, movable connection part 110c) provided so as to face each other along the width direction of the merchandise shelf 11 and electrically connecting the respective first conductors 110a respectively. The respective second conductors 110b and 110c are formed so as to be moved along the facing direction of the respective second conductors 110b and 110c. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a reader / writer antenna capable of communicating with, for example, an RFID tag attached to a product displayed on a product shelf.

  Conventionally, as this type of reader / writer antenna, an antenna that is provided on the upper surface of a product shelf and is formed in a rectangular loop shape along the outer periphery of the product shelf is known (for example, see Patent Document 1). .

The reader / writer antenna is configured to perform non-contact communication with an RFID tag attached to a product based on a signal transmitted from a reader / writer connected to the antenna.
JP 2004-140513 A

  By the way, the products displayed on the product shelf have different sizes and shapes depending on the types of products, and the RFID tag attached to the product can be attached or attached according to the size or shape of the products. Placed in. In this case, since the distance between the RFID tag and the reader / writer antenna varies depending on the position of the RFID tag, that is, for each product, it is necessary to set the antenna size so that the antenna can communicate with the RFID tag. .

  However, since the size of the conventional reader / writer antenna is set in advance, if the size of the product displayed on the product shelf is different, the reader can communicate with the RFID tag attached to the product shelf. The writer antenna must be designed, and there is a problem that the manufacturing cost of the reader / writer antenna and the product shelf provided with the antenna is increased.

  The present invention has been made in view of the above circumstances, and the object of the present invention is to easily set the communicable range with the RFID tag attached to the product on the product shelf according to the position of the RFID tag. An object of the present invention is to provide a reader / writer antenna that can be set.

  In order to achieve the above object, the present invention provides a reader / writer antenna capable of communicating with an RFID tag attached to a product displayed on a product shelf, in either the width direction or the front-rear direction of the product shelf. A pair of first conductors provided so as to face each other, and provided so as to face each other along either the width direction or the front-rear direction of the product shelf. A pair of second conductors to be electrically connected is provided, and at least one of each first conductor and each second conductor is formed so as to be movable along the opposing direction.

  As a result, a loop antenna composed of each first conductor and each second conductor is formed, and at least one of each first conductor and each second conductor is formed so as to be movable along each facing direction. Therefore, the size of the loop antenna can be changed based on the movement of each conductor.

  In order to achieve the above object, the present invention provides a reader / writer antenna capable of communicating with an RFID tag attached to a product displayed on a product shelf, in either the width direction or the front-rear direction of the product shelf. A pair of first conductors provided to face each other along one side, and provided to face each other along either the width direction or the front-rear direction of the product shelf, A set of second conductors for electrically connecting the first conductors on one end side, a set of third conductors provided so as to face each other along any one of the above, and any of the above A pair of fourth conductors that are provided so as to face each other along the other and electrically connect each second conductor on the other end of the other, and each first conductor And one of each third conductor, and each One of the two conductors and one of the one and of the fourth conductor are movably formed along each of opposite directions.

  Thereby, the first loop antenna composed of each first conductor and each second conductor is formed on one end side in either the width direction or the front-rear direction of the product shelf, and each third conductor and A second loop antenna composed of each fourth conductor is formed on one of the other end sides, and one of each first conductor and one of each third conductor and one of each second conductor. And one of each of the fourth conductors is formed so as to be movable along the opposing direction, so that the sizes of the first and second loop antennas are changed based on the movement of each conductor. It becomes possible to do.

  According to the present invention, since the size of the loop antenna can be changed based on the movement of each conductor, the communicable range with the RFID tag attached to the product on the product shelf is determined according to the position of the RFID tag. Can be set easily. Therefore, even when a product having a different size or shape is newly displayed on the product shelf, it is not necessary to design a new reader / writer antenna that can communicate with the RFID tag attached to the product. Further, it is possible to reduce the manufacturing cost of the product shelf provided with the same.

  A reader / writer antenna according to a first embodiment of the present invention will be described with reference to the drawings. The reader / writer antenna according to the present embodiment is connected to a reader / writer that reads and writes information stored in an RFID tag. For example, a product shelf of a showcase that displays a plurality of products such as paper packs and beverages in plastic bottles. Is provided. The reader / writer antenna transmits and receives signals to and from the RFID tag attached to the product on the product shelf in a contactless manner. In this case, by using a store computer (not shown) provided in the store and a reader / writer, the information stored in the RFID tag of each product in the showcase is totaled every predetermined time, so It becomes possible to automatically manage the expiration date.

  First, a showcase provided with a reader / writer antenna will be described. FIG. 1 is a perspective view of the showcase. The showcase 10 includes a plurality of product shelves 11 for displaying the product A and a cooling mechanism for cooling the product A. An RFID tag (not shown) is affixed to the product A, and a unique number representing identification information of the RFID tag is stored in advance in the RFID tag. Since the cooling mechanism is the same as that conventionally known, the description thereof is omitted here. A LAN is constructed in the store, and the store computer and the showcase 10 are connected to the LAN.

  FIG. 2 shows a functional block diagram of the showcase 10. As shown in FIG. 2, this showcase 10 includes a reader / writer 100 that reads and writes information stored in the RFID tag, and a control device that is interposed between the reader / writer 100 and the store computer and controls the reader / writer 100. 12. In FIG. 2, the description of the cooling mechanism and the like is omitted for simplification of description.

  The control device 12 includes a control unit 12a that counts and transmits the RFID tag unique numbers received from the reader / writer 100 to the store computer, a storage unit 12b that stores the unique numbers tabulated in the control unit 12a, and a reader / writer. A communication interface 12c for connecting to the LAN 100 and a communication interface 12d for connecting to the LAN are provided.

  When the control unit 12a transmits an inventory management tag detection request to the reader / writer 100 to be connected every predetermined time (for example, 1 hour) and receives the RFID tag unique number from the reader / writer 100, the unique number Is transmitted to the store computer via the communication interface 12d and the LAN. In addition, the control unit 12a stores the unique number received from the RFID tag in the storage unit 12b.

  A plurality of reader / writer antennas (loop antennas) 110 provided on the corresponding product shelves 11 are connected to the reader / writer 100. The reader / writer 100 also includes a control unit 101 that controls the entire reader / writer 100, a communication circuit unit 102, a plurality of matching circuits 103, and a communication interface 104 for connecting to the control device 12.

  Upon receiving the information display tag detection request from the control device 12, the control unit 101 generates an impedance adjustment control signal, an antenna switching control control signal, and a product information acquisition signal and transmits them to the communication circuit unit 102. Thus, the unique number of the RFID tag of the product A displayed on the product shelf 11 is sequentially acquired using each loop antenna 110. Then, the control unit 101 transmits all the acquired unique numbers to the control device 12 via the communication interface 104.

  The communication circuit unit 102 is configured by a known mixer or the like, and transmits a product information acquisition signal received from the control unit 101 superimposed on an impedance adjustment control signal to the matching circuit 103. The communication circuit unit 102 is provided with switching means such as a switch. When the communication circuit unit 102 receives a control signal for antenna switching control from the control unit 101, the matching circuit 103 corresponding to the control signal. The superimposition signal is transmitted to.

  Each matching circuit 103 is provided with one or a plurality of series circuits of a predetermined impedance element and a switch element such as a transistor or a relay switch, and switches on / off of the switch element based on a control signal for impedance adjustment. Thus, the constant can be switched. For the impedance adjustment method, the technique described in Japanese Patent Application No. 2007-78874 proposed by the applicant can be used.

  Next, the loop antenna 110 will be described. 3 is a perspective view of the loop antenna 110, and FIG. 4 is a plan view of the loop antenna 110. The loop antenna 110 is made of a conductor such as copper wire or copper foil, and is provided on the upper surface of the commodity shelf 11. The loop antenna 110 extends in the width direction (X direction in the figure) of the product shelf 11 and is a set of a pair provided so as to face each other along the front-rear direction (Y direction in the figure) of the product shelf 11. The first conductor 110a, the connecting portion 110b that electrically connects the first conductors 110a on one end side in the width direction of the product shelf 11 (left side in the figure), and the product shelf 11 move along the width direction The connecting portion 110b and the movable connecting portion 110c that are electrically connected to the first conductors 110a so as to face each other along the width direction of the commodity shelf 11 are formed. Note that the connecting portion 110b and the movable connecting portion 110c constitute a set of second conductors in the claims of the present application.

  The connecting portion 110b is formed so as to extend in the front-rear direction of the product shelf 11, and is provided integrally with each first conductor 110a. The movable connecting portion 110c is provided on the lower end side of the product partition plate 13 formed so as to be movable along the width direction on the product shelf 11, and is formed to extend in the front-rear direction of the product shelf 11. ing. Further, the front and rear end portions 110d of the movable connection portion 110c are electrically connected to the first conductors 110a.

  The loop antenna 110 configured as described above can be changed in size by moving the product partition plate 13 in the width direction of the product shelf 11 as shown in FIG. That is, when the product partition plate 13 is moved to the other end in the width direction (the right side in the figure), the movable connecting portion 110c is also moved to the other end in the width direction, whereby each first conductor 110a, the connecting portion 110b and the movable portion The size of the loop antenna 110 including the connection part 110c is increased. Further, when the product partition plate 13 is moved to one end in the width direction (left side in the figure), the movable connecting portion 110c is also moved to one end in the width direction, so that the size of the loop antenna 110 is reduced. Thereby, the size of the loop antenna 110 can be easily changed according to the size of the product A.

  As described above, according to the loop antenna 110 according to the present embodiment, the size of the loop antenna 110 can be changed based on the movement of the second conductor, that is, the movable connecting portion 110c. It is possible to easily set the communicable range with the RFID tag attached to the item according to the position of the RFID tag. Therefore, even when a product having a different size or shape is newly displayed on the product shelf, it is not necessary to newly design the loop antenna 110 that can communicate with the RFID tag attached to the product A. The manufacturing cost of the product shelf 11 provided with the same can be reduced.

  In addition, one of the second conductors, that is, the movable connecting portion 110c is formed so as to be movable along the direction facing the connecting portion 110c (the width direction of the product shelf 11). The conductor 110a can be provided integrally. Therefore, the number of parts of the loop antenna 110 can be reduced, and the manufacturing cost of the loop antenna 110 and the commodity shelf 11 provided with the loop antenna 110 can be further reduced.

  The reader / writer antenna according to the second embodiment of the present invention will be described below. This embodiment is different from the first embodiment in that not only the movable connecting portion 110c but also the connecting portion 110e is provided so as to be movable along the width direction of the commodity shelf 11. Since other configurations and operations are the same as those in the first embodiment, only differences will be described here.

  The connecting portion 110e of the present embodiment is provided on the lower end side of the second product partition plate 14 formed so as to be movable along the width direction on the product shelf 11, and extends in the front-rear direction of the product shelf 11. It is formed as follows. In addition, both front and rear end portions 110f of the connecting portion 110e are electrically connected to the first conductors 110a.

  As shown in FIG. 5, the loop antenna 110 configured as described above has its size increased by moving the product partition plate 13 and the second product partition plate 14 along the width direction of the product shelf 11. It becomes possible to change. Further, in this case, the arrangement position of the loop antenna 110 on the product shelf 11 can be moved along the width direction of the product shelf 11, so that the product A is one end in the width direction as in the first embodiment. There is no need to place them side by side. Therefore, by using the loop antenna 110 of the present embodiment, the arrangement position of the product A on the product shelf 11 can be flexibly changed.

  As described above, according to the loop antenna 110 according to the present embodiment, since the connecting portion 110e and the movable connecting portion 110c are provided so as to be movable along the width direction of the product shelf 11, the product A is arranged at one end in the width direction or in the width direction. Since there is no need to arrange the product A on the other end side, the arrangement of the product A on the product shelf 11 can be flexibly changed.

  The reader / writer antenna according to the third embodiment of the present invention will be described below. This embodiment differs from the first embodiment in that a second loop antenna 120 is provided in addition to the loop antenna 110 (hereinafter referred to as the first loop antenna 110). Since other configurations and operations are the same as those in the first embodiment, only differences will be described here.

  FIG. 6 is a perspective view of the first loop antenna 110 and the second loop antenna of the present embodiment, and FIG. 7 is a plan view of the loop antennas 110 and 120. The second loop antenna 120 is made of a conductor such as copper wire or copper foil, for example, and is provided on the upper surface of the product shelf 11 and inside the first loop antenna 110. The second loop antenna 120 extends in the width direction (X direction in the figure) of the product shelf 11 and is provided so as to face each other in the front-rear direction (Y direction in the figure) of the product shelf 11. The third conductor 120a, the second connection portion 120b for electrically connecting the third conductors 120a on the other end in the width direction (right side in the figure) of the product shelf 11, and the width of the product shelf 11 The second connecting portion 120b is formed so as to be movable along the direction, and includes a second movable connecting portion 120c that electrically connects each third conductor 120a so as to face the width direction of the commodity shelf 11. Has been. The second loop antenna 120 is connected to the reader / writer 100 in the same manner as the first loop antenna 110, and is controlled by the control unit 101 of the reader / writer 100. Further, the second connecting portion 120b and the second movable connecting portion 120c constitute a set of fourth conductors referred to in the claims of the present application.

  The 2nd connection part 120b is formed so that it may extend in the front-back direction of the goods shelf 11, and is provided integrally with each 3rd conductor 120a. The second movable connecting portion 120 c is provided at the lower end on the other end side in the width direction (right side in the figure) of the product partition plate 13 and is formed to extend in the front-rear direction of the product shelf 11. Further, the front and rear end portions 120d of the second movable connection portion 120c are electrically connected to the third conductors 120a.

  The loop antennas 110 and 120 configured as described above can be changed in size by moving the product partition plate 13 in the width direction of the product shelf 11 as shown in FIG. . That is, when the product partition plate 13 is moved to the other end in the width direction (the right side in the figure), the movable connecting portion 110c and the second movable connecting portion 120c are also moved to the other end in the width direction, thereby While the size of the first loop antenna 110 including the conductor 110a, the connection portion 110b, and the movable connection portion 110c is increased, the first loop antenna 110 includes the third conductor 120a, the second connection portion 120b, and the second movable connection portion 120c. The size of the second loop antenna 120 is reduced. In addition, when the product partition plate 13 is moved to one end in the width direction (left side in the figure), the movable connecting portion 110c and the second movable connecting portion 120c are also moved to the one end in the width direction. While the size of the second loop antenna 120 increases. Accordingly, even when different types of products are displayed on one product shelf 11, the sizes of the loop antennas 110 and 120 can be easily changed according to the size of each product.

  As described above, according to the loop antenna 110 according to the present embodiment, one of the second conductors, that is, the movable connection portion 110c and one of the fourth conductors, that is, the second movable connection portion 120c are arranged in the respective opposing directions ( Since it is formed to be movable along the X direction in the drawing, the sizes of the loop antennas 110 and 120 can be changed based on the movement of the movable connecting portion 110c and the second movable connecting portion 120c. Thereby, the communicable range with the RFID tag attached to the product A on the product shelf 11 can be easily set according to the position of the RFID tag. Even when different types of products are displayed on one product shelf 11, the sizes of the loop antennas 110 and 120 can be easily changed according to the size of each product. Therefore, even when a product having a different size or shape is newly displayed on the product shelf, it is not necessary to newly design the loop antennas 110 and 120 that can communicate with the RFID tag attached to the product A. 110, 120 and the manufacturing cost of the product shelf 11 provided with them can be reduced.

  The reader / writer antenna according to the fourth embodiment of the present invention will be described below. This embodiment is different from the third embodiment in that the second connection portion 120b is provided so as to be movable along the width direction of the commodity shelf 11. Since other configurations and operations are the same as those of the third embodiment, only the differences will be described here.

  The second connection portion 120e of the present embodiment is provided on the lower end side of the third product partition plate 15 formed to be movable on the product shelf 11 along the width direction. It is formed to extend in the direction. Further, the front and rear end portions 120f of the second connection portion 120e are electrically connected to the third conductors 120a.

  As shown in FIG. 8, the second loop antenna 120 configured as described above has a size by moving the product partition plate 13 and the third product partition plate 15 in the width direction of the product shelf 11. Can be changed. In this case, since the arrangement position of the second loop antenna 120 on the product shelf 11 can be moved along the width direction of the product shelf 11, the product A as in the third embodiment. There is no need to place it close to the other end in the width direction. Therefore, the arrangement position of the product A on the product shelf 11 can be flexibly changed.

  As described above, according to the loop antenna of the present embodiment, the other of the second conductors, that is, the connecting portion 110e is provided to be movable along the width direction of the commodity shelf 11, and therefore communicates with the first loop antenna 110. Since it is not necessary to arrange the product A with the possible RFID tag attached to one end in the width direction, the arrangement position of the product A can be flexibly changed.

  In addition, the other of the fourth conductors, that is, the second connection portion 120e is provided so as to be movable along the width direction of the commodity shelf 11, so that an RFID tag that can communicate with the second loop antenna 120 is attached. Since it is not necessary to arrange the product A close to the other end in the width direction, the arrangement position of the product A can be flexibly changed.

  In addition, the said embodiment is only a specific example of this invention, and this invention is not limited only to the said embodiment. For example, in the above-described embodiment, the first conductors 110a and the third conductors 120a are provided so as to extend in the width direction of the commodity shelf 11, and the second conductors 110b and 110c and the fourth conductors 120b, Although 120c is provided so as to extend in the front-rear direction of the product shelf 11, each first conductor 110a and each third conductor 120a are extended in the front-rear direction of the product shelf 11 as shown in FIG. In addition, the second conductors 110 b and 110 c and the fourth conductors 120 b and 120 c may be provided so as to extend in the width direction of the product shelf 11.

  Moreover, you may form each width direction one end side of each 1st conductor 110a shown in FIG. 9 and each 3rd conductor 120a so that a movement in the width direction of the goods shelf 11 is possible. Thereby, the width direction of each loop antenna 110,120 and the size of the front-back direction can be changed.

Perspective view of showcase Functional block diagram of showcase The perspective view of the antenna for reader / writers which shows the 1st Embodiment of this invention Plan view of the reader / writer antenna shown in FIG. The top view of the antenna for reader / writers which shows the 2nd Embodiment of this invention The perspective view of the antenna for reader / writers which shows the 3rd Embodiment of this invention. Plan view of the reader / writer antenna shown in FIG. The top view of the antenna for reader / writers which shows the 4th Embodiment of this invention The figure which shows the modification of the antenna for reader / writers

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Showcase, 11 ... Multiple goods shelf, 100 ... Reader / writer, 110 ... Loop antenna, 110a ... A set of 1st conductors, 110b, 110e ... Connection part, 110c ... Movable connection part, 120 ... Second Loop antenna, 120a, a set of third conductors, 120b, 120e, a second connection portion, 120c, a second movable connection portion, A, a product.

Claims (6)

In the reader / writer antenna that can communicate with the RFID tag attached to the product displayed on the product shelf,
A set of first conductors provided to face each other along either the width direction or the front-rear direction of the product shelf;
A pair of second conductors that are provided so as to oppose each other along either the width direction or the front-rear direction of the product shelf, and electrically connect each first conductor;
An antenna for a reader / writer, wherein at least one of each first conductor and each second conductor is formed so as to be movable in the opposing direction. The reader / writer antenna according to claim 1, wherein at least one of the first conductors is formed so as to be movable along a direction in which the first conductors face each other. 3. The reader / writer antenna according to claim 1, wherein at least one of the second conductors is formed to be movable along a direction in which the second conductors face each other. In the reader / writer antenna that can communicate with the RFID tag attached to the product displayed on the product shelf,
A set of first conductors provided to face each other along either the width direction or the front-rear direction of the product shelf;
A pair of second conductors provided so as to oppose each other along either the width direction or the front-rear direction of the product shelf, and electrically connecting each first conductor on one end side of the other Conductors,
A set of third conductors provided to face each other along any one of the above,
A pair of fourth conductors that are provided so as to face each other along the other, and electrically connect each second conductor on the other end of the other,
One of each first conductor and one of each third conductor, and one of each of the second conductors and one of each of the fourth conductors are formed so as to be movable along the respective opposing directions. A reader / writer antenna. 5. The reader / writer antenna according to claim 4, wherein the other of the second conductors is formed to be movable along a direction in which the second conductors face each other. 6. The reader / writer antenna according to claim 5, wherein the other of the fourth conductors is formed so as to be movable along the facing direction of the fourth conductors.

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