RFID tag reader

Abstract

To provide an RFID tag reader with a simple configuration which is configured to read RFID tags without omission and properly regulate a read range outside the device, especially a read range above the device.SOLUTION: An RFID reader includes: an outer case 11 made of a material through which radio waves for communication with an RFID tag does not pass, the case having a bottom wall 111, side walls 112, and an opening formed at the top; and an inner case 12 made of a material through which the radio waves for communication with the RFID tag passes. The inner case includes a recess 13 into which a commodity with the RFID tag is put, and a frame part 121 formed around the recess. A predetermined space is formed between a wall forming the recess and the outer case. Antennas 114 for communication with the RFID tag are attached at an elevation angle with respect to the side walls, in positions located inside the side walls and offset from the horizontal center of the side walls, the positions being offset in opposite directions on the facing side walls.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an RFID tag reader, and more particularly to a reader that can simultaneously read RFID tags attached to a large number of products stored in a shopping cart or the like. [Background technology]

[0002] In recent years, products using RFID tags (also known as contactless IC tags or IC tags, and hereinafter simply referred to as "tags") have been offered on the market, and are being put to practical use, with stores using them for inventory management, payment management, and shoplifting prevention, and manufacturers and in the distribution process for product quality control (detection of adulteration, etc.) and inventory management. RFID tags in particular can send and receive data wirelessly between reader devices or reader / writer devices (hereinafter collectively referred to as reader devices), making the above tasks extremely efficient.

[0003] As an example of such a device, cited document 1 discloses an IC tag reading device in which the antenna of an IC tag reader / writer is placed on a horizontal plate at the bottom of a housing that is open at the top, and another horizontal plate above that serves as a shopping cart mounting area, with a radio wave reflecting sheet and a radio wave absorbing sheet attached to the inner wall surface, and the device is said to be able to read the IC tags of multiple products stored in a shopping cart placed on the mounting area.

[0004] However, in the reader of Cited Document 1, the antenna is only provided on the bottom, so blind spots are likely to occur in the corners of the housing or shopping cart, and the antenna is directed toward the upper opening, so the reading radio waves are not restricted in the height direction, as clearly shown in Figure 3, and there is a risk of mistakenly reading products that happen to be above or diagonally above the cart. In order to control the height at which reading is possible, it is necessary to suppress the output of the radio waves, but weakening the radio waves to prevent misreadings also poses the problem of a decrease in the reading rate of tags inside the housing.

[0005] Furthermore, cited document 2 discloses a bagging system equipped with a bagging device and an information acquisition device, in which the bottom plate of a shopping cart containing products slides open, the products are transferred to the loading surface of the lifting section, and the lifting section descends, storing the products in bags that have been set on the loading surface in advance, and an antenna provided on the side wall of the lifting section communicates with the RF tags attached to the products, allowing a reading device to read the RF tags of the products.

[0006] However, the system in Cited Document 2 is designed for self-checkout systems, and the device itself is large, requiring a large amount of space in the store, and there are problems such as high installation and maintenance costs. In addition, there is a possibility that store clerks and customers may be confused about how to use the device, so it becomes necessary to explain how to use it to them. Furthermore, since it is specialized for self-checkout systems, it is difficult to apply it to inventory management, etc. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 6469758 [Patent Document 2] International Publication No. 2018 / 139291 Summary of the Invention [Problem to be solved by the invention]

[0008] Therefore, the present invention can be applied to self-checkouts in stores and inventory management of products, and can read the RFID tags of products inserted into the device without fail, and can also detect RFID tags on the outside of the device. The present invention aims to provide a simple-structured RFID tag reader that does not erroneously read RFID tags and that can appropriately restrict the reading range, particularly above the device. [Means for solving the problem]

[0009] In order to solve the above problems, the present invention provides: An RFID tag reader, an outer box having a rectangular parallelepiped envelope shape with a bottom wall and side walls and an opening at the top, made of a material that is opaque to radio waves used for communication with the RFID tag; an inner box that is placed on the outer box so as to cover the opening and is made of a material that transmits radio waves for communication with the RFID tag; The inner box has a recess into which products with RFID tags are inserted, and a frame around the recess. The frame portion connects the upper end of the side wall of the outer box to the inner box, and a predetermined space is formed between the wall forming the recess and the outer box, Antennas for communication with RFID tags are attached to the inner surface of each side wall of the outer box at positions offset from the horizontal center of the side wall, and on opposing side walls at positions offset in opposite directions; The antenna is mounted at an elevation angle relative to the side wall. The RFID tag reader is characterized by the above.

[0010] In the RFID tag reader, The material that is opaque to radio waves for communication with the RFID tag may be a metal.

[0011] In the RFID tag reader, The material that transmits radio waves for communication with the RFID tag may be a plastic resin.

[0012] In the RFID tag reader, A metal film may be formed on the inner surface of the inner box from the frame to the upper part of the recess.

[0013] In the RFID tag reader, A resistive film may be provided to cover the upper part of the antenna, and a metal film may be provided to cover a part of the upper part of the resistive film.

[0014] In the RFID tag reader, An electromagnetic wave absorbing material may be attached to the inner surface of the bottom wall, side wall, or both of the walls of the outer box.

[0015] In the RFID tag reader, The recess may be large enough to accommodate a shopping basket. [Effects of the Invention]

[0016] The RFID tag reading device of the present invention can read all RFID tags of products with attached RFID tags that are placed in the recess, has little risk of accidentally reading RFID tags of products outside the reading device, and can appropriately regulate the reading range of RFID tags, particularly those above or diagonally above the device. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a schematic external view of a first embodiment of an RFID tag reader according to the present invention; [Figure 2] 1 is a schematic cross-sectional view of a first embodiment of an RFID tag reader according to the present invention. [Figure 3] 3 is an explanatory diagram of the internal configuration of an outer box of the first embodiment of the RFID tag reader of the present invention. FIG. [Figure 4] FIG. 10 is a schematic cross-sectional view of a second embodiment of an RFID tag reader according to the present invention. [Figure 5] 10 is an explanatory diagram of the internal configuration of an outer box of a second embodiment of an RFID tag reader of the present invention. FIG. [Figure 6] FIG. 10 is a schematic cross-sectional view of a third embodiment of an RFID tag reader according to the present invention. [Figure 7] 10 is an explanatory diagram of the internal configuration of an outer box of a third embodiment of an RFID tag reader of the present invention. FIG. [Figure 8] 10 is a partially enlarged view of the inside of an outer box of a third embodiment of an RFID tag reader of the present invention. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the embodiments described below. Furthermore, in the embodiments described below, technically preferable limitations are imposed for carrying out the invention, but these limitations are not essential requirements for the present invention. Furthermore, below and in the drawings, equivalent components and the like may be designated by the same reference numerals and their description may be omitted.

[0019] 1 is a schematic external view of a first embodiment of an RFID tag reader (hereinafter also simply referred to as a "reader") of the present invention. The reader 10 has an envelope shape that is approximately rectangular parallelepiped on the outside, and is comprised of an outer box 11 that is open at the top and made of a material that is opaque to radio waves used for communication with RFID tags. An inner box 12 made of a material that is transparent to radio waves used for communication with RFID tags is placed on top of the outer box 11 and covers the opening of the outer box 11. A recess 13 is provided in the approximate center of the inner box 12, and a frame 121 surrounds the recess 13 and connects to a wall 122 that forms the recess 13. The upper ends of the side walls 112 of the outer box 11 are joined to the frame 121, thereby integrating the outer box 11 and the inner box 12.

[0020] As a material that constitutes outer box 11 and that is opaque to radio waves used for communication with the RFID tag, metals such as iron plate, stainless steel plate, and aluminum plate are preferably used in terms of processability and strength. As a material that constitutes inner box 12 and that is permeable to radio waves used for communication with the RFID tag, wood, cardboard, etc. can also be used, but plastic resin is preferably used in terms of formability, strength, water resistance, ease of handling, etc. The type of resin is not particularly limited and may be appropriately selected from general resins that have good formability, such as polypropylene resin.

[0021] 2, outer box 11 has a shape in which side walls 112 are erected from each side of rectangular bottom wall 111, and recess 13 of inner box 12 is formed so as to form a predetermined space between outer box 11 and inner box 12. Furthermore, since recess 13 is the portion into which products 141 with RFID tags attached are placed, it is preferable that it is large enough to store products 141 inside, and in particular, if it is large enough to store a typical shopping basket 14 used in supermarkets, convenience stores, etc., it is preferable as it is highly convenient because it allows products 141 to be placed inside shopping basket 14.

[0022] Typical shopping baskets are approximately 450 to 570 mm wide, 330 to 370 mm deep, and 240 to 255 mm high, so the size of recess 13 is not particularly limited as long as it can accommodate such shopping baskets with a certain degree of room to spare. For example, the interior dimensions can be set to approximately 500 to 600 mm wide, 350 to 400 mm deep, and 240 to 300 mm deep, and it is preferable to set these dimensions appropriately according to the application.

[0023] In the space between the outer box 11 and the inner box 12, an antenna 114 for communicating with an RFID tag is attached to the inner surface of each of the four side walls 112 of the outer box 11. The following are characteristics that are required for the antenna 114 to read the RFID tag attached to the product 141: (1) All RFID tags inside the inner box or shopping cart are read. (2) RFID tags outside the reader are not read. (3) However, the top of the reader can read RFID tags up to a certain height. When there are a large number of products, the products may be piled high in recess 12 or shopping basket 14, so characteristics such as (3) are required. The height at which reading is possible from the top of reader 10 is, for example, 50 cm to 1 m above reader 10, and it is more preferable to set it to about 50 cm.

[0024] Therefore, as shown in the explanatory diagram of the internal configuration of the outer box in FIG. 3 , the antenna 114 in the reader of the present invention is offset by L1, L2, L3, and L4 from the horizontal center of each of the four side walls 112, and is attached to the side walls 112 at positions offset in opposite directions from each other on opposing side walls 112, i.e., so that when facing each side wall from the inside, the antenna 114 is offset in the same direction, and is attached to the side walls 112 so that the angle θ relative to the side walls 112 forms an elevation angle. The angle θ is within the range of 0°<θ<90°, and can be set appropriately depending on the size of the reader 10 and the recess 12. However, the range of 0°<θ<45° is more preferable, and for a size that can accommodate a typical shopping basket 14 as described above, a value of around 10° is most preferable. The values ​​of the offsets L1, L2, L3, and L4 are set appropriately depending on the characteristics of the antenna 114 and the size of the inner box 12.

[0025] Generally, the directionality of the radio waves emitted from antenna 114 is strongest in the normal direction of the antenna surface and becomes weaker as it moves away from the normal direction. Therefore, by installing the antenna in the manner described above, it is less likely that areas of weak radio wave strength will be created within recess 13, and RFID tags attached to products 141 placed in recess 13 can be read without exception by any of the four antennas. It is also possible to prevent radio waves from leaking above reading device 10, thereby preventing misreading of RFID tags located above or diagonally above reading device 10. For example, an elevation angle of 10° makes it possible to read RFID tags within a range of up to about 50 cm above reading device 10.

[0026] The antenna 114 is connected to a separately provided RFID tag reader main body (not shown). In this embodiment, radio wave absorbing material 113 is attached to the inner surfaces of the bottom wall 111 and side walls 112. The inner box 12 is made of plastic resin and transmits radio waves used for communication between the antenna 114 and the RFID tag attached to the product 141, so that communication is not impeded. On the other hand, the outer box 11 is made of metal and does not transmit radio waves emitted from the antenna, so that leakage of radio waves below or to the sides of the reader 10 can be prevented, and erroneous reading of RFID tags below or to the sides of the reader 10 can be prevented.

[0027] Furthermore, it is more preferable to attach radio wave absorbing material 113 to the inner surface of outer box 11, since this can suppress the generation of noise due to the reflection of radio waves inside outer box 11. Radio wave absorbing material 113 may be attached to either bottom wall 111 or side wall 112, or both.

[0028] Furthermore, as shown in FIG. 1, the reading device 10 can be configured to be relatively small with a simple box-like structure, and can be easily moved on a cart or the like. It is not limited to use at checkout registers in stores. If a power source is available, it can be used in stores, backrooms, or warehouses to check inventory, and can read entire boxes containing RFID-tagged products, etc., at the same time, making it suitable for inventory management applications.

[0029] The reader 10 configured as above provides the following advantages. By installing multiple antennas, there are no blind spots where RFID tags inside the inner box cannot be read, and RFID tags can be read throughout the entire inner box. By attaching the antenna at an elevation angle to the side wall, the antenna can be installed on the bottom. Compared to the previous model, it is possible to narrow the reading area in the height direction and also to read a certain range of the upper part of the inner box.

[0030] Fig. 4 is a cross-sectional schematic diagram of a second embodiment of an RFID tag reader of the present invention. Fig. 5 is an explanatory diagram of the internal configuration of the outer box of the second embodiment. The general shapes and materials of outer box 11 and inner box 12, and the manner in which antenna 114 is attached in reader 10a of this embodiment are the same as those in the first embodiment. However, in reader 10a, metal film 115 is formed around the inner surface of the upper part of wall 122 that forms frame 121 and recess 13 of inner box 12. In this embodiment, radio wave absorbing material 113 is attached to the inner surface of side wall 112.

[0031] There are no particular limitations on the metal film 115, as long as it is impermeable to the radio waves emitted from the antenna 114, but examples include thin aluminum sheets and aluminum foil. As mentioned above, the radio waves emitted from the antenna 114 are strongest in the normal direction, but they are also emitted in other directions, and there is a possibility that radio waves irregularly reflected internally may be emitted slightly in the direction of the frame portion 121 in Figure 4. Therefore, if a product with an RFID tag is located above the reader 10a in that direction, it may be read incorrectly. In contrast, by forming the metal film 115, the radio waves from the antenna 114 are reflected and can be blocked from being emitted to the outside, further reducing the possibility of misreading.

[0032] To avoid reading RFID tags that do not need to be read, it is possible to simply reduce the antenna output, but this would make it more likely that RFID tags that need to be read within the reader will not be read. In the reader 10a of this embodiment, there is no need to reduce the antenna output, and there is no risk of missing a tag. This also leads to an increase in the number of tags that can be read.

[0033] That is, the reading device 10a of this embodiment has the following advantages. Installing multiple antennas makes it easier for radio waves to leak outside the reader 10a, but providing a metal film that reflects radio waves on the frame and the top of the recess prevents radio waves from leaking, suppresses radio waves from spreading outside the reader 10a, and prevents misreading. - The radio wave output of the antenna itself is not weakened, so even if there are many RFID tags in the box, the tags inside the reader can be read accurately. As a result, the number of tags that can be read increases.

[0034] FIG. 6 is a cross-sectional schematic diagram of a third embodiment of an RFID tag reader of the present invention. FIG. 7 is an explanatory diagram of the internal configuration of the outer box of the third embodiment. The general shapes and materials of the outer box 11 and inner box 12 and the mounting arrangement of the antenna 114 in the reader 10b of this embodiment are the same as those in the first embodiment. However, in the reader 10b, as shown in the partially enlarged view of FIG. 8, a resistive film 116 covers the upper portion of the antenna 114. The coverage ratio is preferably approximately 50% or less of the upper side of the antenna 114, but this can be appropriately set depending on the size of the reader 10, the recess 12, and the elevation angle of the antenna. The resistive film 116 has the property of attenuating the radio waves emitted from the antenna 114. Therefore, in the reader 10b of this embodiment, it particularly serves to attenuate radio waves directed upward from the reader 10b. The resistive film 116 can be attached to the surface of the antenna 114 using, for example, an adhesive sticker. The resistive film 116 can be appropriately selected from among those generally used for absorbing electromagnetic waves and converting them into heat, and can be, for example, a dielectric sheet on which ITO is vapor-deposited. In this embodiment, a radio wave absorbing material 113 is attached to the inner surface of the bottom wall 111.

[0035] Furthermore, a metal film 117 is formed on the inner surface of the upper portion of the resistive film 116. The metal film 117 is not particularly limited, but may be, for example, an aluminum adhesive sticker or aluminum foil. Forming the metal film 117 together with the resistive film 116 prevents the radio waves emitted from the antenna 114 from spreading too far outside the reader 10b, reducing the possibility of accidentally reading RFID tags on products that do not need to be read, and further reducing the possibility of misreading. Also, in this embodiment, there is no need to reduce the antenna output, so there is less chance of missed readings.

[0036] That is, the reader 10b of this embodiment has the following advantages. By attaching a resistive film that weakens radio waves and a metal film that reflects radio waves to the antenna, the spread of radio waves is suppressed, and radio waves that spread outside the reader 10b are suppressed, thereby preventing misreading. - The radio wave output of the antenna itself is not weakened, so even if there are many RFID tags in the box, the tags inside the reader can be read accurately. As a result, the number of tags that can be read increases.

[0037] Furthermore, although not specifically shown, it is also possible to combine the configurations of the second and third embodiments, form a metal film 115 around the inner surface of the upper part of the wall 122 that forms the frame part 121 and the recess 13 of the inner box 12, and further cover the upper part of the antenna 114 with a resistive film 116, and form a metal film 117 on the inner surface of the upper part of the resistive film 116, thereby obtaining the same effect as described above.

[0038] As described above in each embodiment, the RFID tag reading device of the present invention realizes a relatively small, box-shaped reading device that can read multiple products with RFID tags all at once by inserting them into the device. Furthermore, the device does not require a separate location for absorbing radio waves or a separate radio wave absorber. Furthermore, because the device is not large and is box-shaped, it is easy to move and highly convenient. Furthermore, it can be significantly cheaper than a large device, making it possible to reduce installation costs while improving the efficiency of store operations, inventory management, and other operations.

[0039] Specific examples of applications include the following: <Use for self-checkout> This is a compact, box-shaped RFID tag reader that can read RFID tags attached to products purchased by customers and process the transaction by reading all of the tags at once, and is shaped to fit a shopping cart. Even if RFID-tagged products are not in the shopping cart, RFID-tagged products can be placed directly into the device, and the RFID tags can be read all at once. <Inventory management applications for reading multiple RFID tags at once> This box-shaped RFID tag reader can read all RFID-tagged products at once and manage inventory when checking inventory in stores or warehouses. This RFID tag reader allows you to check the quantity of items by placing the items you want to read in a shopping cart.You can also check the quantity by placing the items you want to check directly into the reader without using a shopping cart, or by placing the box or container containing the RFID-tagged items directly into the reader.

[0040] <Experimental Example> An RFID tag reading test was conducted using the configurations shown in Figures 6 and 7. The elevation angle of the antenna was set to 10°. <Evaluation results> ·misreading : Misreading from the side was improved by approximately 40% compared to a configuration in which one antenna was installed on the bottom wall facing upwards.

[0041] In terms of height, the reading height was 40% shorter than in a configuration where one antenna was installed on the bottom wall facing upward. [Explanation of symbols]

[0042] 10, 10a, 10b... RFID tag reader 11. Outer box 12...Inner box 13. Recess 14···Shopping Cart 111 Bottom wall 112...side wall 113... Radio wave absorbing material 114 Antenna 115 Metal Film 116···Resistive film 117···Metal Film 121... Frame 122....Recess wall 141···Product

Claims

1. An RFID tag reader, an outer box having a rectangular parallelepiped envelope shape with a bottom wall and side walls and an opening at the top, the outer box being made of a material that is opaque to radio waves used for communication with the RFID tag; an inner box that is placed on the outer box so as to cover the opening and is made of a material that transmits radio waves for communication with the RFID tag; The inner box has a recess into which a product with an RFID tag is inserted and a frame around the recess. The frame portion connects the upper end of the side wall of the outer box to the inner box, and a predetermined space is formed between the wall forming the recess and the outer box, Antennas for communication with the RFID tag are attached on the inner surface of each side wall of the outer box at positions offset from the horizontal center of the side wall, and on opposing side walls at positions offset in opposite directions; The antenna is mounted at an elevation angle of 0°<θ<45° relative to the sidewall. An RFID tag reader characterized by:

2. 2. The RFID tag reader according to claim 1, wherein the material that is opaque to radio waves for communication with the RFID tag is a metal.

3. 3. The RFID tag reader according to claim 1, wherein the material that transmits radio waves for communication with the RFID tag is a plastic resin.

4. An RFID tag reading device as described in any one of claims 1 to 3, characterized in that a metal film is formed from the frame portion of the inner box to the top of the recess, surrounding the inner surface of the frame portion and the top of the recess.

5. 5. The RFID tag reader according to claim 1, further comprising a resistive film covering an upper portion of the antenna, and a metal film covering a part of an upper portion of the resistive film.

6. An RFID tag reader, an outer box having a rectangular parallelepiped envelope shape with a bottom wall and side walls and an opening at the top, the outer box being made of a material that is opaque to radio waves used for communication with the RFID tag; an inner box that is placed on the outer box so as to cover the opening and is made of a material that transmits radio waves for communication with the RFID tag; The inner box has a recess into which a product with an RFID tag is inserted and a frame around the recess. The frame portion connects the upper end of the side wall of the outer box to the inner box, and a predetermined space is formed between the wall forming the recess and the outer box, Antennas for communication with the RFID tag are attached on the inner surface of each side wall of the outer box at positions offset from the horizontal center of the side wall, and on opposing side walls at positions offset in opposite directions; The antenna is mounted at an elevation angle relative to the sidewall; a resistive film covering an upper portion of the antenna and a metal film covering a part of an upper portion of the resistive film; An RFID tag reader characterized by:

7. 7. The RFID tag reader according to claim 1, wherein a radio wave absorbing material is attached to the inner surface of the bottom wall, the side wall, or both of the bottom wall and the side wall of the outer box.

8. 8. The RFID tag reader according to claim 1, wherein the recess has a size that allows a shopping basket to be stored therein.

Images