RF tag reading device

Abstract

To reduce the possibility of failing to read information from an RF tag from which information is to be acquired, to prevent information from being erroneously read from RF tags around an RF tag reader, and to improve usability.SOLUTION: The upper portion 110 includes a placement portion 111 and a prohibition portion 112. The placement portion 111 and the prohibition portion 112 are made of a material that transmits radio waves. The article 300 to which the RF tag 301 is attached is placed on the upper surface of the placement portion 111. The prohibiting portion 112 surrounds the placing portion 111. There is a gap between the outer edge 1111 of the placing portion 111 and the outer edge 1122 of the prohibiting portion 112. Placement of RF tag 301 is prohibited in prohibition portion 112. An antenna for communicating with the RF tag 301 is provided under the placement portion 111. The antenna radiates a radio wave having a large intensity toward the placement portion 111 and radiates a radio wave having an intensity smaller than that of the radio wave radiated toward the placement portion 111 toward the prohibition portion 112.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an RF tag reader that reads information from a passive RF (Radio Frequency) tag. [Background technology]

[0002] It is known that the strength of the radio waves received by an RF tag can be weakened depending on the orientation of the RF tag relative to the antenna of an RFID (Radio Frequency Identification) reader / writer. For example, if the RFID reader / writer antenna emits circularly polarized radio waves, and the radio waves emitted from the RFID reader / writer antenna are weak, the RF tag may not function and may not be able to transmit information in response to the received radio waves if the longitudinal direction of the RF tag's antenna is nearly perpendicular to the surface of the RFID reader / writer's antenna. It is also known that the strength of the radio waves received by each RF tag is weakened when multiple RF tags are stacked on top of each other.

[0003] On the other hand, RF tags used for apparel inventory, incoming and outgoing product inspection in logistics, fixed asset management in the manufacturing industry, etc. generally use radio waves in the UHF (Ultra High Frequency) band with a frequency of 860 to 960 MHz. At such a relatively low frequency, it is known that when radio waves are blocked by an obstacle, they diffract and go around behind the obstacle.

[0004] Patent Document 1 describes an RF tag reader having an opening at the top of a storage compartment, which acquires information from a passive RF tag inside the storage compartment when the opening is open. The left, back, and right side sections each include a radio wave absorbing layer and are higher than the front section. The interior of the storage compartment is divided into an attenuation space between the front section and the front storage limit section, and a storage space between the front storage limit section and the back section. The storage space can accommodate items with RF tags attached, but the attenuation space cannot accommodate items. A bottom antenna is installed on the top surface of the bottom section in a position that radiates high-intensity radio waves toward the storage space and radiates low-intensity radio waves toward the attenuation space.

[0005] In the RF tag reader described in Patent Document 1, radio waves emitted from the bottom antenna are significantly attenuated when they reach the upper ends of the left side, rear, and right side. Radio waves emitted from the bottom antenna toward the front of the storage unit are significantly attenuated as they propagate through the attenuation space. This RF tag reader therefore reduces the possibility of failing to read information from an RF tag stored in the storage unit and prevents erroneous acquisition of information from an RF tag outside the storage unit due to radio wave diffraction at the periphery of the opening. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 7429399 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the left side, back, and right side of the housing unit of the RF tag reader described in Patent Document 1 must be at a height that can prevent radio waves emitted upward from the bottom antenna from diffracting at the periphery of the opening when they reach the upper end of the housing unit, thereby erroneously acquiring information from an RF tag outside the housing unit.As a result, the left side, back, and right side of this RF tag reader may be too high, making it difficult to use.

[0008] The object of the present invention is to provide an RF tag reading device that reduces the possibility of failing to read information from the RF tag from which information is to be acquired, prevents erroneous reading of information from surrounding RF tags, and improves ease of use. [Means for solving the problem]

[0009] In order to achieve the above object, the RF tag reader of the present invention comprises: an upper portion made of a material that transmits radio waves and having a mounting portion on which an item with a passive RF tag attached is placed, and an upper portion made of a material that transmits radio waves and having a prohibition portion that surrounds the mounting portion and prohibits placing an RF tag thereon, with a gap between the outer edge of the mounting portion and the outer edge of the prohibition portion; an antenna for communicating with the RF tag, the antenna being located below the placement section and positioned to radiate radio waves with high intensity toward the placement section and to radiate radio waves with lower intensity than the radio waves radiated toward the placement section toward the prohibition section; Equipped with By providing a gap between the outer edge of the placement section and the outer edge of the prohibition section, it is possible to reduce the possibility of failing to read information from an RF tag attached to an item placed on the top surface of the placement section and to prevent erroneous reading of information from RF tags around the top.

[0010] Preferably, the RF tag reader of the present invention comprises: By providing a gap between the outer edge of the mounting section and the outer edge of the prohibition section, the strength of the radio waves radiated by the antenna and reaching the mounting section can be made to be above a predetermined strength, and the radio waves radiated by the antenna and reaching the area around the upper part can be made to be of a strength that will not cause the RF tag to operate.

[0011] Preferably, the RF tag reader of the present invention comprises: Because there is a gap between the outer edge of the placement section and the outer edge of the prohibition section, a difference occurs between the strength of the radio waves radiated by the antenna and reaching the placement section and the strength of the radio waves radiated by the antenna and reaching the surrounding area of ​​the upper section, making it possible to determine whether the RF tag is on the placement section or around the upper section.

[0012] Preferably, the RF tag reader of the present invention comprises: The mounting portion is circular, The radio waves radiated by the antenna are circularly polarized, and the center of the radiation area of ​​the antenna that radiates the radio waves is located directly below the center of the mounting portion.

[0013] Preferably, the RF tag reader of the present invention comprises: an electromagnetic wave absorbing wall having an inner surface in contact with a part of an outer edge of the upper portion, extending above and below the upper portion, and absorbing electromagnetic waves; The gap between the outer edge of the placement section and the outer edge of the prohibition section, and the presence of the radio wave absorbing wall, reduce the possibility of failing to read information from RF tags attached to items placed on the top surface of the placement section, and prevent erroneous reading of information from RF tags around the top.

[0014] Preferably, the RF tag reader of the present invention comprises: Because there is a gap between the outer edge of the mounting section and the outer edge of the prohibition section, and because there is the radio wave absorbing wall, the strength of the radio waves radiated by the antenna and reaching the mounting section can be made to be above a predetermined strength, and the radio waves radiated by the antenna and reaching the area around the upper part can be made to be of a strength that will not cause the RF tag to operate.

[0015] Preferably, the RF tag reader of the present invention comprises: Because there is a gap between the outer edge of the placement section and the outer edge of the prohibition section, and because there is the radio wave absorbing wall, a difference occurs between the strength of the radio waves radiated by the antenna and reaching the placement section and the strength of the radio waves radiated by the antenna and reaching the surroundings of the upper section, making it possible to determine whether the RF tag is on the placement section or around the upper section.

[0016] Preferably, the RF tag reader of the present invention comprises: The mounting portion is circular, The radio waves radiated by the antenna are circularly polarized, and the center of the radiation area of ​​the antenna that radiates the radio waves is located directly below the center of the mounting portion. [Effects of the Invention]

[0017] According to the present invention, it is possible to reduce the possibility of failing to read information from the RF tag from which information is to be acquired, prevent erroneous reading of information from RF tags surrounding the RF tag reader, and improve ease of use. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a perspective view of an example of an RF tag reader according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a top view of the RF tag reader of FIG. [Figure 3] FIG. 2 is a cross-sectional view taken along line AA in FIG. [Figure 4] 3 is a diagram showing an example of radio waves emitted from an antenna in the RF tag reader according to the first embodiment. FIG. [Figure 5] 1. FIG. 4 is a diagram showing a prohibition unit that is a first modified example of the prohibition unit in the RF tag reader of FIG. [Figure 6] 1. FIG. 4 is a diagram showing a prohibition unit that is a second modified example of the prohibition unit in the RF tag reader of FIG. [Figure 7] FIG. 2 is a top view of an RF tag reader that is a modified example of the RF tag reader according to the first embodiment. [Figure 8] FIG. 8 is a cross-sectional view taken along line BB in FIG. 7. [Figure 9] FIG. 8 is a cross-sectional view taken along line CC in FIG. [Figure 10] FIG. 10 is a perspective view of an example of an RF tag reader according to a second embodiment of the present invention. [Figure 11] FIG. 11 is a cross-sectional view taken along the line DD in FIG. [Figure 12] FIG. 10 is a diagram showing an example of radio waves emitted from an antenna in an RF tag reader according to a second embodiment. [Figure 13] FIG. 10 is a perspective view of an example of an RF tag reader according to a third embodiment of the present invention. [Figure 14] FIG. 14 is a cross-sectional view taken along the line EE in FIG. [Figure 15] FIG. 10 is a diagram showing an example of radio waves emitted from an antenna in an RF tag reader according to a third embodiment. [Figure 16] FIG. 10 is a top view of an example of an RF tag reader according to a fourth embodiment of the present invention. [Figure 17] FIG. 17 is a front view of the RF tag reader of FIG. [Figure 18] FIG. 17 is a side view of the RF tag reader of FIG. [Figure 19] FIG. 17 is a cross-sectional view taken along the line FF in FIG. 16. [Figure 20] FIG. 10 is a diagram showing an example of radio waves emitted from an antenna in an RF tag reader according to a fourth embodiment. [Figure 21] FIG. 10 is a top view of an RF tag reader which is a first modified example of an RF tag reader according to a fourth embodiment of the present invention. [Figure 22]FIG. 13 is a top view of an RF tag reader which is a second modified example of the RF tag reader according to the fourth embodiment of the present invention. [Figure 23] FIG. 10 is a top view of an example of an RF tag reader according to a fifth embodiment of the present invention. [Figure 24] 24 is a cross-sectional view taken along line GG in FIG. 23. [Figure 25] FIG. 13 is a top view of an RF tag reader that is a comparative example of the fourth embodiment. [Figure 26] 26A and 26B are diagrams showing an example of a dual RF tag, in which Fig. 26A is a plan view of the dual RF tag, and Fig. 26B is a front view of the dual RF tag. [Figure 27] 2 is a diagram showing an example in which a duplicated RF tag is placed on a placement section of the RF tag reader of FIG. 1. FIG. [Figure 28] 28A and 28B are diagrams showing a dual RF tag which is a different configuration example from the dual RF tag shown in Fig. 26. Fig. 28A is a plan view of the dual RF tag, and Fig. 28B is a front view of the dual RF tag. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, an RF tag reader according to an embodiment of the present invention will be described in detail with reference to the drawings. In all the drawings describing the embodiment, the same components are designated by the same reference numerals, and repeated description will be omitted.

[0020] FIG. 1 is a perspective view of an example of an RF tag reader 1 according to a first embodiment of the present invention. FIG. 2 is a top view of the RF tag reader 1 of FIG. 1. FIG. 3 is a cross-sectional view taken along line AA of FIG. 1. The RF tag reader 1 is used, for example, in a cash register operated by a store clerk or a self-checkout operated by a customer in a store. The RF tag reader 1 has a reading unit 100 and a control unit 200. The reading unit 100 has a top 110, a side 120, a bottom 130, and an antenna 131.

[0021] The upper portion 110 has a mounting portion 111 and a prohibition portion 112. The mounting portion 111 is made of a material that transmits radio waves. The material that transmits radio waves is, for example, wood, but other materials are also possible. The mounting portion 111 has a shape that corresponds to the polarization of the radio waves radiated by the antenna 131. If the polarization of the radio waves radiated by the antenna 131 is, for example, circular polarization, the mounting portion 111 is a circular flat plate. However, in this case, the shape of the mounting portion 111 does not necessarily have to be a perfect circle, and may be a circle close to a perfect circle depending on the radiation characteristics of the radio waves of the antenna 131. An item 300 with a passive RF tag 301 attached is placed on the upper surface of the mounting portion 111. The item 300 is, for example, a product. The item 300 is contained inside a shopping basket 302, and the shopping basket 302 may be placed on the upper surface of the mounting portion 111.

[0022] The RF tag 301 is used, for example, for the centralized management of multiple items throughout the entire supply chain, including production, intermediate logistics, and sales. The RF tag 301 is used, for example, for product inventory management (inspection and inventory) in factories, product inspection and inventory in intermediate logistics, and cash registers and self-checkouts in stores. The RF tag reader 1 communicates with the RF tag 301 using radio waves in the UHF band with a frequency of 860 to 960 MHz, for example. When the item 300 to which the RF tag 301 is attached is placed on the top surface of the placement unit 111, the RF tag reader 1 reads information including a tag ID (IDentification) from the RF tag 301.

[0023] The prohibition section 112 is made of a material that transmits radio waves. The prohibition section 112 is, for example, annular. The inner edge 1121 of the prohibition section 112 is in contact with the outer edge 1111 of the placement section 111, and the prohibition section 112 surrounds the placement section 111. There is a gap between the outer edge 1111 of the placement section 111 and the outer edge 1122 of the prohibition section 112. Placing an item on the prohibition section 112 is prohibited. An RF tag 301 cannot be placed on the prohibition section 112. As shown in FIG. 3 , the cross section of the prohibition section 112 is, for example, L-shaped. The prohibition section 112 consists of a parallel portion that is parallel to the placement section 111 and a vertical portion that is perpendicular to the placement section 111. The upper end of the vertical portion is fixed to the inner edge of the parallel portion. The lower end of the vertical portion is fixed to, for example, the outer edge 1111 of the placement section 111. Since the prohibition portion 112 has a vertical portion, the placement portion 111 is recessed relative to the prohibition portion 112, making it easier to place the article 300 or the shopping basket 302 on the placement portion 111.

[0024] The placement portion 111 and the prohibition portion 112 may be on the same plane. In this case, there is no vertical portion in the prohibition portion 112. In this configuration, it is desirable to provide a mark on the top surface of the upper portion 110 so that the placement portion 111 and the prohibition portion 112 can be distinguished from each other.

[0025] The side portion 120 is, for example, cylindrical. The lower end of the side portion 120 is fixed to the outer edge of the bottom portion 130. The side portion 120 stands vertically from the outer edge of the bottom portion 130. The upper end of the side portion 120 is fixed to the outer edge of the parallel part of the forbidden portion 112 (i.e., the outer edge 1122 of the forbidden portion 112). The side portion 120 is made of a material that transmits radio waves.

[0026] The bottom 130 is, for example, a circular flat plate. The bottom 130 may be made solely of a material that transmits radio waves, or may include a radio wave absorbing layer that absorbs radio waves or a radio wave reflecting layer that reflects radio waves. An antenna 131 is installed on the upper surface of the bottom 130. The antenna 131 is an antenna for communicating with the RF tag 301. The antenna 131 emits radio waves upward to communicate with the RF tag 301, and receives a response radio wave transmitted by the RF tag 301 that has received the radio waves. The antenna 131 is, for example, a planar antenna or a sheet antenna. The antenna 131 emits circularly polarized radio waves, or alternately emits two linearly polarized radio waves whose polarization directions are orthogonal to each other. Note that horizontal polarization and vertical polarization are examples of two linearly polarized radio waves whose polarization directions are orthogonal to each other. The antenna 131 is located below the mounting unit 111. The radio waves emitted from antenna 131 propagate while spreading upward. Antenna 131 is installed in a position where it radiates radio waves with high intensity toward mounting portion 111 and radiates radio waves with lower intensity than the radio waves radiated toward mounting portion 111 toward prohibition portion 112. When antenna 131 radiates circularly polarized radio waves, it is desirable that it is installed so that the center of the region where the radio waves are radiated is located directly below the center of mounting portion 111.

[0027] The control unit 200 has a transmitting / receiving unit 201, an acquiring unit 202, and an I / F (interface) 203. The transmitting / receiving unit 201 causes the antenna 131 to emit a circularly polarized radio wave, or to emit two linearly polarized radio waves whose polarization directions are orthogonal to each other. When the antenna 131 receives a response radio wave transmitted from the RF tag 301, the transmitting / receiving unit 201 acquires information including the tag ID from the response radio wave.

[0028] The RF tag 301 obtains the power necessary for operation by receiving radio waves transmitted from the antenna 131. If the strength of the radio waves received by the RF tag 301 is lower than a predetermined value, the RF tag 301 does not operate and does not transmit a response radio wave.

[0029] FIG. 4 shows an example of radio waves emitted from the antenna 131 in the RF tag reader 1 according to the first embodiment. In the example of FIG. 4, the RF tag 301 that receives radio waves within the range indicated by the diagonal dashed line sloping upward to the right will activate. The radio waves emitted from the antenna 131 are attenuated to an intensity at which the RF tag 301 will not activate when they reach the outer edge 1122 of the prohibited section 112. That is, the transceiver 201 causes the antenna 131 to emit radio waves of an intensity at which the RF tag 301 will not activate when they reach the outer edge 1122 of the prohibited section 112. In the RF tag reader 1, because there is a gap between the outer edge 1111 of the placement section 111 and the outer edge 1122 of the prohibited section 112, the intensity of the radio waves radiated by the antenna 131 and reaching the placement section 111 is equal to or greater than a predetermined intensity, and the radio waves radiated by the antenna 131 and reaching the periphery of the upper portion 110 will be of an intensity at which the RF tag 301 will not activate.

[0030] For example, when the longitudinal direction of the antenna of the RF tag 301 is nearly perpendicular to the main surface of the antenna 131 or when multiple RF tags 301 are overlapped, the radio waves received by the antenna of the RF tag 301 are weakened. However, the strength of the radio waves radiated from the antenna 131 toward the mounting unit 111 is strong. Therefore, the RF tag 301 attached to the article 300 placed on the upper surface of the mounting unit 111 operates, and information about the RF tag 301 attached to the article 300 placed on the upper surface of the mounting unit 111 can be obtained. There is little possibility that the transmitting / receiving unit 201 fails to read information from the RF tag 301 placed on the upper surface of the mounting unit 111.

[0031] On the other hand, the strength of the radio waves radiated from antenna 131 toward prohibited section 112 is weak. If RF tag 301 were placed on the top surface of prohibited section 112, there is a risk that RF tag 301 would not function if the longitudinal direction of the antenna of RF tag 301 were nearly perpendicular to the main surface of antenna 131 or if multiple RF tags 301 were overlapping. In other words, there is a possibility that transceiver unit 201 would fail to read information from that RF tag 301. However, RF tag 301 is not placed on the top surface of prohibited section 112. Because the radio waves radiated by antenna 131 and reaching the periphery of upper part 110 are of such strength that RF tag 301 would not function, transceiver unit 201 can exclude RF tags 301 around upper part 110 from the targets for reading information.

[0032] Furthermore, stores usually have ceilings. When the RF tag reader 1 is used in a store, radio waves emitted from the antenna 131 may be reflected by the ceiling and reach RF tags 301 around the upper part 110 (i.e., RF tags 301 that are not above the upper part 110). However, the radio waves are attenuated before they reach the ceiling, and the reflected waves from the ceiling are further attenuated before they reach RF tags 301 around the upper part 110. The transmitter / receiver 201 causes the antenna 131 to emit radio waves of an intensity that will prevent RF tags 301 around the upper part 110 from operating due to the radio waves reflected by the ceiling.

[0033] If the RF tag 301 does not operate, it will not transmit any response radio waves, and therefore the RF tag reader 1 will not acquire information from the RF tags 301 around the upper part 110. Therefore, the RF tag reader 1 is less likely to fail to read information from the RF tags 301 placed on the top surface of the placement section 111, and can prevent erroneous reading of information from the RF tags 301 around the upper part 110.

[0034] The acquisition unit 202 identifies each RF tag 301 and acquires information about each RF tag 301 contained in the response radio wave received by the antenna 131. The I / F 203 transmits the information about the RF tag 301 acquired by the acquisition unit 202 to an external device (e.g., an accounting device) and receives operation instructions for the RF tag reading device 1 from the external device.

[0035] In addition, when the mounting portion 111 is a circular flat plate, the prohibition portion 112 is annular, the antenna 131 emits circularly polarized radio waves, and the antenna 131 is installed so that the center of the area emitting the radio waves is located directly below the center of the mounting portion 111, the distance between the outer edge 1111 of the mounting portion 111 and the outer edge 1122 of the prohibition portion 112 can be made constant.

[0036] Furthermore, in the first embodiment described above, an example was shown in which the mounting portion 111 was a circular flat plate, but this is not limiting, and the mounting portion 111 may have any other shape, such as a rectangular flat plate.

[0037] The control unit 200 can also be realized by a commercially available RFID reader / writer.

[0038] FIG. 5 shows a prohibition section 112A, which is a first modified example of the prohibition section 112 in the RF tag reader 1 of FIG. 1. The cross-sectional shape of the prohibition section 112A consists of a sector-shaped arc portion with a central angle of 90 degrees or less and a vertical portion extending vertically downward from one end of the arc portion. The lower end of the vertical portion is fixed to the outer edge 1111 of the placement section 111. The side of the vertical portion fixed to the outer edge 1111 is the inner edge 1121A of the prohibition section 112A. The other end of the arc portion is fixed to the upper end of the side section 120. The other end side of the arc portion is the outer edge 1122A of the prohibition section 112A. The placement section 111 is recessed with respect to the prohibition section 112A. Note that a cross-sectional shape consisting of a sector-shaped arc portion with a central angle of 90 degrees or less and a vertical portion extending vertically downward from one end of the arc portion is an example of a shape that makes it difficult to place an item on it.

[0039] FIG. 6 shows a prohibition section 112B, which is a second modified example of the prohibition section 112 in the RF tag reader 1 of FIG. 1. The cross-sectional shape of the prohibition section 112B is an arc portion of a fan shape with a central angle of 180 degrees or less. One end of the arc portion is fixed to the outer edge 1111 of the placement section 111. One end side of the arc portion is the inner edge 1121B of the prohibition section 112B. The other end of the arc portion is fixed to the upper end of the side section 120. The other end side of the arc portion is the outer edge 1122B of the prohibition section 112B. The placement section 111 is recessed with respect to the prohibition section 112B. Note that an arc portion of a fan shape with a central angle of 180 degrees or less is another example of a shape that makes it difficult to place an item on it.

[0040] Fig. 7 is a top view of an RF tag reader 2 which is a modified example of the RF tag reader 1 according to the first embodiment. Fig. 8 is a cross-sectional view taken along line BB in Fig. 7. Fig. 9 is a cross-sectional view taken along line CC in Fig. 7. The RF tag reader 2 has a base 400, and the upper part 110, control unit 200, and antenna 131 of the RF tag reader 1 according to the first embodiment.

[0041] The stand 400 has a top surface 410, a bottom surface 420, a front surface 430, a left side surface 431, and a right side surface 432. The top surface 410, the bottom surface 420, the front surface 430, the left side surface 431, and the right side surface 432 are, for example, rectangular flat plates. The back surface of the stand 400 is open. A hole 411 is formed in the top surface 410 of the stand 400. The upper portion 110 of the RF tag reader 1 according to the first embodiment is attached to the hole 411. In the area of ​​the top surface 410 of the stand 400 excluding the upper portion 110, for example, a cash register or the like can be installed. Customers can also place their purchased items in a bag in this area.

[0042] However, the prohibited portion 112C included in the upper portion 110 is a modification of the prohibited portion 112. While the prohibited portion 112 was composed of a parallel portion and a vertical portion, the prohibited portion 112C has a first vertical portion attached to the inner edge of the parallel portion and a second vertical portion attached to the outer edge of the parallel portion. The side of the prohibited portion 112C facing the first vertical portion is the inner edge 1121C of the prohibited portion 112C, and the side of the second vertical portion is the outer edge 1122C of the prohibited portion 112C. This results in a convex cross-sectional shape of the prohibited portion 112C. The prohibited portion 112C protrudes upward from the upper surface portion 410 of the base 400. The placement portion 111 is recessed relative to the prohibited portion 112C.

[0043] The control unit 200 is installed, for example, on the upper surface of the bottom surface 420. The antenna 131 is installed, for example, above the control unit 200, at a position where it radiates radio waves with a high intensity toward the mounting unit 111 and radiates radio waves with an intensity lower than the radio waves radiated toward the mounting unit 111 toward the prohibition unit 112C. When the antenna 131 radiates circularly polarized radio waves, it is desirable that it be installed so that the center of the region from which the radio waves are radiated is located directly below the center of the mounting unit 111. Note that the antenna 131 may be installed on the upper surface of the bottom surface 420 instead of on the control unit 200.

[0044] Fig. 10 is a perspective view of an example of an RF tag reader 3 according to a second embodiment of the present invention. Fig. 11 is a cross-sectional view taken along line DD in Fig. 10. The RF tag reader 3 has a reading unit 100 and a control unit 210. The configuration of the reading unit 100 according to the second embodiment is the same as the configuration of the reading unit 100 of the RF tag reader 1 according to the first embodiment.

[0045] However, the radio wave output of the antenna 131 in the RF tag reader 3 according to the second embodiment is greater than that of the RF tag reader 1 according to the first embodiment. FIG. 12 shows an example of radio waves emitted from the antenna 131 in the RF tag reader 3 according to the second embodiment. In the example of FIG. 12, an RF tag 301 that receives radio waves within the range indicated by the diagonal dashed line sloping upward to the right will operate. This range extends beyond the outer edge 1122 of the prohibited section 112. Therefore, RF tags 301 around the upper part 110 may operate and transmit response radio waves. However, because there is a gap between the outer edge 1111 of the mounting section 111 and the outer edge 1122 of the prohibited section 112, a difference occurs between the strength of the radio waves radiated by the antenna 131 and reaching the mounting section 111 and the strength of the radio waves radiated by the antenna 131 and reaching the periphery of the upper part 110. This allows the RF tag reader 3 to determine whether the RF tag 301 is on the placement section 111 or around the upper section 110, as will be described below.

[0046] The control unit 210 has a transmitting / receiving unit 211, a determining unit 212, an acquiring unit 213, and an I / F (interface) 214. The transmitting / receiving unit 211 causes the antenna 131 to radiate radio waves with a high intensity toward the mounting unit 111, and to radiate radio waves with a lower intensity than the radio waves radiated toward the mounting unit 111 toward the prohibition unit 112.

[0047] If the RF tag 301 has a function for transmitting a received signal strength indicator (RSSI), the transmitter / receiver 211 acquires information including the RSSI and tag ID from the response radio wave when the antenna 131 receives the response radio wave from the RF tag 301. Here, the RSSI indicates the strength of the radio wave emitted from the antenna 131 and received by the RF tag 301.

[0048] Then, based on the RSSI acquired from the response radio wave received by the antenna 131, the discrimination unit 212 determines whether the RF tag 301 from which this RSSI was acquired is located around the upper part 110 or on the mounting unit 111 (i.e., on the upper part 110). For example, if the RSSI acquired from the response radio wave received by the antenna 131 is equal to or greater than a predetermined first threshold, the discrimination unit 212 determines that the RF tag 301 is located on the mounting unit 111. On the other hand, if the RSSI acquired from the response radio wave received by the antenna 131 is equal to or less than a predetermined second threshold, the discrimination unit 212 determines that the RF tag 301 is located around the upper part 110.

[0049] Alternatively, when the antenna 131 receives a response radio wave from the RF tag 301, the transmitter / receiver 211 acquires information including the intensity of the response radio wave and the tag ID from the response radio wave. The determination unit 212 determines whether the RF tag 301 from which the intensity of the response radio wave was acquired is located around the upper part 110 or on the mounting unit 111, based on the intensity of the response radio wave acquired from the response radio wave received by the antenna 131. For example, the determination unit 212 determines that the RF tag 301 is located on the mounting unit 111 when the intensity of the response radio wave acquired from the response radio wave received by the antenna 131 is equal to or greater than a predetermined third threshold. On the other hand, the determination unit 212 determines that the RF tag 301 is located around the upper part 110 when the intensity of the response radio wave acquired from the response radio wave received by the antenna 131 is equal to or less than a predetermined fourth threshold.

[0050] In the example of Figure 12, there is a possibility that the RF tag 301 around the upper part 110 will be activated. However, the radio waves radiated from the antenna 131 are attenuated by the time they reach the outer edge 1122 of the prohibited area 112. The strength of the radio waves radiated from the antenna 131 and leaking around the upper part 110 is small. Moreover, there is no RF tag 301 above the prohibited area 112. There is a large difference in the strength of the radio waves leaking around the upper part 110 and the strength of the radio waves above the mounting area 111. The strength of the radio waves above the mounting area 111 is much greater than the strength of the radio waves leaking around the upper part 110. It is unlikely that the transceiver 211 will fail to read information from the RF tag 301 placed on the top surface of the mounting area 111.

[0051] On the other hand, when the antenna 131 receives a response radio wave from an RF tag 301 that has been activated by receiving radio waves leaking around the upper part 110, the RSSI or strength of the response radio wave acquired from the response radio wave is much smaller than the RSSI or strength of the response radio wave acquired from the response radio wave transmitted from the RF tag 301 on the mounting part 111. Based on the RSSI or strength of the response radio wave acquired from the response radio wave received by the antenna 131, the discrimination part 212 can determine whether the RF tag 301 from which the RSSI or strength of the response radio wave was acquired is located around the upper part 110 or on the mounting part 111.

[0052] Furthermore, stores usually have ceilings. When the RF tag reader 3 is used in a store, radio waves emitted from the antenna 131 may be reflected by the ceiling and reach the RF tags 301 around the upper part 110. However, the radio waves are attenuated before reaching the ceiling, and the reflected waves are further attenuated before reaching the RF tags 301 around the upper part 110. When the RF tags 301 around the upper part 110 are activated by the reflected waves and transmit response radio waves, the response radio waves may also be reflected by the ceiling and reach the antenna 131. However, even in this case, the discrimination unit 212 can determine that the RF tags 301 whose RSSI or response radio wave strength has been acquired are located around the upper part 110, based on the RSSI or the strength of the response radio waves acquired from the response radio waves received by the antenna 131. In the RF tag reading device 3, the transmitter / receiver unit 211 causes the antenna 131 to emit radio waves of an intensity that allows the discrimination unit 212 to determine that the RF tag 301 is located near the upper part 110 based on the RSSI contained in the response radio waves or the strength of the response radio waves transmitted from the RF tag 301, even if the RF tag 301 located near the upper part 110 is activated by radio waves reflected by the ceiling.

[0053] Therefore, in the RF tag reading device 3, when the antenna 131 receives a response radio wave from the RF tag 301, because there is a gap between the outer edge 1111 of the placing section 111 and the outer edge 1122 of the prohibition section 112, it is possible to obtain information on the RF tag 301 attached to the item 300 placed on the upper surface of the placing section 111, excluding the RF tags 301 around the upper section 110. The RF tag reading device 3 is less likely to fail to read information from the RF tag 301 placed on the upper surface of the placing section 111, and can prevent erroneous reading of information from the RF tags 301 around the upper section 110.

[0054] For example, when the determination unit 212 determines that an RF tag 301 is on the mounting unit 111, the acquisition unit 213 identifies each RF tag 301 and acquires information read from each RF tag 301. Therefore, when the antenna 131 receives a response radio wave from an RF tag 301, the RF tag reader 3 can distinguish between the RF tag 301 on the mounting unit 111 and the RF tags 301 around the upper part 110 and acquire information from the RF tag 301 on the mounting unit 111.

[0055] The I / F 214 transmits the information acquired by the acquisition unit 213 to an external device (for example, a checkout device) and receives operation instructions from the external device.

[0056] In addition, the acquisition unit 213 may also acquire information about the RF tag 301 that the discrimination unit 212 has determined to be located around the upper part 110, and the I / F 214 may transmit the information about the RF tag 301 to an external device along with information indicating whether the RF tag 301 is located on the placement unit 111 or around the upper part 110.

[0057] The control unit 210 can also be realized by a commercially available RFID reader / writer.

[0058] 7 to 9, as a modification of the RF tag reader 3 according to the second embodiment, an RF tag reader can be configured that includes a base 400, an upper portion 110, the control unit 210 of the RF tag reader 2 according to the second embodiment, and an antenna 131. However, in this configuration, the top surface 410 of the base 400 is made only of a material that transmits radio waves, and does not include a radio wave absorbing layer or a radio wave reflecting layer.

[0059] In the RF tag reader 1 according to the first embodiment and the RF tag reader 3 according to the second embodiment described above, the side portion 120 is made only of a material that transmits radio waves. However, the inside surface of the side portion may be entirely or partially covered with a radio wave absorbing layer. Figures 13 to 15 show an example of an RF tag reader 4, which is a variation of the RF tag reader 1 according to the first embodiment, in which the side portion 121 includes a radio wave absorbing layer that absorbs radio waves.

[0060] FIG. 13 is a perspective view of an example of an RF tag reader 4 according to a third embodiment of the present invention. FIG. 14 is a cross-sectional view taken along the line E-E in FIG. 13. The RF tag reader 4 includes a reading unit 101 and a control unit 200. The reading unit 101 includes an upper portion 110, a side portion 121, a bottom portion 130, and an antenna 131. The side portion 121 includes a radio wave absorbing layer that absorbs radio waves, and differs from the side portion 120 of the RF tag reader 1 according to the first embodiment in that it absorbs radio waves. In other respects, the configuration of the reading unit 101 and the configuration of the reading unit 100 are the same. The side portion 121 is cylindrical. The side portion 121 is made of, for example, a plate material that absorbs radio waves. The side portion 121 may be made of a plate material that transmits radio waves, with a radio wave absorbing sheet attached to the inner surface thereof. The side portion 121 may also be configured such that a radio wave reflecting sheet is attached to the inner surface of a plate material that transmits radio waves, and a radio wave absorbing sheet is further attached to the inner surface of the radio wave reflecting sheet. The radio wave absorbing sheet is a sheet made of a material in which magnetic metal powder is mixed with rubber, for example. The control unit 200 is the same as the control unit 200 of the RF tag reader 1 according to the first embodiment.

[0061] Fig. 15 shows an example of radio waves emitted from the antenna 131 in the RF tag reader 4 according to the third embodiment. As shown in Fig. 15, when the radio waves emitted from the antenna 131 reach the outer edge 1122 of the prohibited section 112, diffracted waves are generated. In the example of Fig. 15, the RF tag 301 that receives radio waves within the range indicated by the diagonal dashed line sloping upward to the right operates.

[0062] The radio waves emitted from the antenna 131 are attenuated by the time they reach the outer edge 1122 of the prohibited section 112. The intensity of the diffracted waves is even weaker than the intensity of the radio waves that reach the outer edge 1122 of the prohibited section 112. There is a large difference between the intensity of the diffracted waves and the intensity of the radio waves above the mounting section 111. The intensity of the radio waves above the mounting section 111 is much stronger than the intensity of the diffracted waves. The transmitter / receiver 211 is unlikely to fail to read information from the RF tag 301 mounted on the top surface of the mounting section 111. On the other hand, in the RF tag reader 4, the intensity of the diffracted waves is weak, and the RF tags 301 around the upper part 110 do not function. In the RF tag reading device 4, because there is a gap between the outer edge 1111 of the placement section 111 and the outer edge 1122 of the prohibited section 112, the strength of the radio waves radiated by the antenna 131 and reaching the placement section 111 is equal to or greater than a predetermined strength, and the radio waves radiated by the antenna 131 and reaching the periphery of the upper section 110 are of an intensity that does not activate the RF tag 301. If an RF tag 301 were present above the prohibited section 112, it would likely activate and transmit a response radio wave upon receiving the radio waves radiated from the antenna 131, but no RF tag 301 is present above the prohibited section 112. In the RF tag reading device 4, the RF tag 301 attached to the item 300 placed on the top surface of the placement section 111 will activate, and the transceiver 201 will be able to acquire information about the RF tag 301. On the other hand, because the RF tags 301 around the upper section 110 do not activate, the transceiver 201 can exclude the RF tags 301 around the upper section 110 from the targets from which information is read.

[0063] Furthermore, stores usually have ceilings. When the RF tag reader 4 is used in a store, radio waves emitted from the antenna 131 may be reflected by the ceiling and reach RF tags 301 around the upper part 110 (i.e., RF tags 301 that are not above the upper part 110). However, the radio waves are attenuated before they reach the ceiling, and the reflected waves from the ceiling are further attenuated before they reach RF tags 301 around the upper part 110. The transmitter / receiver 201 causes the antenna 131 to emit radio waves of an intensity that will not cause RF tags 301 around the upper part 110 to operate due to the radio waves reflected by the ceiling.

[0064] If the RF tag 301 does not operate, it will not transmit any response radio waves, and therefore the RF tag reader 4 will not acquire information from the RF tags 301 around the upper part 110. Therefore, the RF tag reader 4 is less likely to fail to read information from the RF tags 301 placed on the top surface of the placement section 111, and can prevent erroneous reading of information from the RF tags 301 around the upper part 110.

[0065] FIG. 16 is a top view of an example of an RF tag reader 5 according to a fourth embodiment of the present invention. FIG. 17 is a front view of the RF tag reader 5 of FIG. 16. FIG. 18 is a side view of the RF tag reader 5 of FIG. 16. FIG. 19 is a cross-sectional view taken along line FF of FIG. 16. The RF tag reader 5 has a reading unit 500 and a control unit 200. The reading unit 500 has an upper part 510, a radio wave absorbing wall 520, a bottom part 530, and an antenna 131. The control unit 200 is the same as the control unit 200 of the RF tag reader 1 according to the first embodiment.

[0066] The upper portion 510 has a mounting portion 111 and a prohibition portion 512. The mounting portion 111 is the same as the mounting portion 111 of the RF tag reader 1 according to the first embodiment. On the other hand, the prohibition portion 512 is made of a material that is transparent to radio waves. The prohibition portion 512 has an inner edge 5121 that contacts the outer edge 1111 of the mounting portion 111, and surrounds the mounting portion 111. There is a gap between the outer edge 1111 of the mounting portion 111 and the outer edge 5122 of the prohibition portion 512. Placing an RF tag 301 on the prohibition portion 512 is prohibited.

[0067] 19, for example, the placement section 111 is recessed relative to the prohibition section 512. With this configuration, it is easier to place the article 300 or the shopping basket 302 on the placement section 111. Furthermore, the placement section 111 and the prohibition section 512 may be on the same plane. With this configuration, it is desirable to provide a mark on the upper surface of the upper section 510 so that the placement section 111 and the prohibition section 512 can be distinguished from each other.

[0068] As shown in FIG. 16, the radio wave absorbing wall 520 has a U-shaped cross section. The radio wave absorbing wall 520 is composed of an arc portion and two protruding portions. The cross section of the arc portion has, for example, a semicircular arc shape. The arc portion and inner surfaces 5201 of the two protruding portions of the radio wave absorbing wall 520 are in contact with the outer edge 5122 of the forbidden portion 512 (i.e., the outer edge of the upper portion 510). The two protruding portions of the radio wave absorbing wall 520 protrude from both ends of the arc portion. Therefore, the inner surface 5201 of the radio wave absorbing wall 520 is in contact with part of the outer edge 5122 of the forbidden portion 512 (i.e., the outer edge of the upper portion 510).

[0069] The radio wave absorbing wall 520 stands vertically from the outer edge of the bottom part 530, for example, and extends above and below the upper part 510. An inner surface 5201 of the radio wave absorbing wall 520 is fixed to a part of the outer edge 5122 of the prohibition part 512 (i.e., the outer edge of the upper part 510). The upper end of the radio wave absorbing wall 520 is higher than the upper surface of the upper part 510. Here, in a configuration in which the placing part 111 is recessed relative to the prohibition part 512, the upper surface of the upper part 510 is the upper surface of the prohibition part 512. Note that it is sufficient for the radio wave absorbing wall 520 to extend above and below the upper part 510, and its lower end does not necessarily have to be fixed to the outer edge of the bottom part 530.

[0070] The radio wave absorbing wall 520 includes a radio wave absorbing layer that absorbs radio waves, and absorbs radio waves. The radio wave absorbing wall 520 is made of, for example, a plate material that absorbs radio waves. The radio wave absorbing wall 520 may be configured such that a radio wave absorbing sheet is attached to the inner surface of a member that transmits radio waves. The radio wave absorbing wall 520 may also be configured such that a radio wave reflecting sheet is attached to the inner surface of a member that transmits radio waves, and further a radio wave absorbing sheet is attached to the inner surface of the radio wave reflecting sheet.

[0071] The bottom 530 is, for example, a flat plate. The bottom 530 has a shape that allows the lower end of the radio wave absorbing wall 520 to be fixed to the outer edge of the bottom 530, so that the radio wave absorbing wall 520 can be erected. The bottom 530 may be made only of a material that transmits radio waves, or may include a radio wave absorbing layer or a radio wave reflecting layer.

[0072] An antenna 131 is installed on the upper surface of the bottom 530. The antenna 131 is the same as the antenna 131 of the RF tag reader 1 according to the first embodiment. The antenna 131 is located below the mounting section 111. The antenna 131 is installed in a position where it radiates radio waves with a high intensity toward the mounting section 111 and radiates radio waves with a lower intensity than the radio waves radiated toward the mounting section 111 toward the prohibited section 512. When radiating circularly polarized radio waves, the antenna 131 is desirably installed so that the center of the region from which the radio waves are radiated is located directly below the center of the mounting section 111.

[0073] FIG. 20 shows an example of radio waves emitted from the antenna 131 in the RF tag reader 5 according to the fourth embodiment. FIG. 20 shows an example of radio waves emitted from the antenna 131 in the cross section of line FF in FIG. 16 shown in FIG. 19. In the example of FIG. 20, the RF tag 301 that receives radio waves within the range indicated by the diagonal dashed line sloping upward to the right operates. The distance between the outer edge 1111 of the mounting section 111 and the outer edge 5122 of the prohibited section 512 is larger on the front side than on the rear side. On the front side, the radio waves emitted from the antenna 131 are attenuated to an intensity at which the RF tag 301 does not operate when they reach the outer edge 5122 of the prohibited section 512. That is, the transceiver 201 causes the antenna 131 to emit, toward the front side, radio waves of an intensity at which the RF tag 301 does not operate when they reach the outer edge 5122 of the prohibited section 512.

[0074] On the other hand, on the rear side, the radio waves radiated from the antenna 131 are attenuated by the time they reach the forbidden section 512. Then, by the time they reach the upper end of the radio wave absorbing wall 520, they are further attenuated. The radio waves are diffracted at the upper end of the radio wave absorbing wall 520, generating diffracted waves. The intensity of the diffracted waves is even weaker than the intensity of the radio waves reaching the upper end of the radio wave absorbing wall 520. The transceiver 201 causes the antenna 131 to radiate, toward the rear side, radio waves of an intensity that will not activate the RF tag 301 due to the diffracted waves. In the RF tag reading device 5, because there is a gap between the outer edge 1111 of the mounting section 111 and the outer edge 5122 of the forbidden section 512, and because there is the radio wave absorbing wall 520, the intensity of the radio waves radiated by the antenna 131 and reaching the mounting section 111 is equal to or greater than a predetermined intensity, and the radio waves radiated by the antenna 131 and reaching the periphery of the upper portion 510 are of an intensity that will not activate the RF tag 301.

[0075] For example, when the longitudinal direction of the antenna of the RF tag 301 is nearly perpendicular to the main surface of the antenna 131 or when multiple RF tags 301 are overlapped, the radio waves received by the antenna of the RF tag 301 are weakened. However, the strength of the radio waves radiated from the antenna 131 toward the mounting unit 111 is strong. Therefore, the RF tag 301 attached to the article 300 placed on the upper surface of the mounting unit 111 operates, and information about the RF tag 301 attached to the article 300 placed on the upper surface of the mounting unit 111 can be obtained. There is little possibility that the transmitting / receiving unit 201 fails to read information from the RF tag 301 placed on the upper surface of the mounting unit 111.

[0076] On the other hand, the strength of the radio waves radiated from antenna 131 toward prohibited section 512 is weak. If RF tag 301 were placed on the top surface of prohibited section 512, there is a risk that RF tag 301 would not function if the longitudinal direction of the antenna of RF tag 301 is nearly perpendicular to the main surface of antenna 131 or if multiple RF tags 301 are overlapping. In other words, there is a possibility that transceiver unit 201 would fail to read information from that RF tag 301. However, RF tag 301 is not placed on the top surface of prohibited section 512. Because the radio waves radiated by antenna 131 and reaching the periphery of upper section 510 are of such strength that RF tag 301 would not function, transceiver unit 201 can exclude RF tags 301 around upper section 510 from the targets for reading information.

[0077] Furthermore, stores usually have ceilings. When the RF tag reader 5 is used in a store, radio waves emitted from the antenna 131 may be reflected by the ceiling and reach RF tags 301 around the upper part 510 (i.e., RF tags 301 that are not above the upper part 510). However, the radio waves are attenuated before they reach the ceiling, and the reflected waves from the ceiling are further attenuated before they reach RF tags 301 around the upper part 510. The transmitter / receiver 201 causes the antenna 131 to emit radio waves of an intensity that will not activate RF tags 301 around the upper part 510 due to the radio waves reflected by the ceiling.

[0078] If the RF tag 301 does not operate, it will not transmit any response radio waves, and therefore the RF tag reader 5 will not acquire information from the RF tags 301 around the upper part 510. Therefore, the RF tag reader 5 is less likely to fail to read information from the RF tags 301 placed on the top surface of the mounting section 111, and can prevent erroneous reading of information from the RF tags 301 around the upper part 510.

[0079] If there is no prohibited section 512 between the mounting section 111 and the radio wave absorbing wall 520 and the inner surface of the radio wave absorbing wall 520 is in contact with the outer edge of the mounting section 111, the radio wave absorbing wall 520 must have a height such that the diffracted waves generated at its upper end attenuate the radio waves radiated from the antenna 131 to an intensity that does not activate the RF tag 301. On the other hand, in the RF tag reading device 5, there is a gap between the outer edge 1111 of the mounting section 111 and the inner surface 5201 of the radio wave absorbing wall 520. The radio waves radiated from the antenna 131 are attenuated by the time they reach the prohibited section 512. Then, these radio waves are further attenuated by the time they reach the upper end of the radio wave absorbing wall 520. Therefore, the height of the radio wave absorbing wall 520 can be reduced depending on the gap between the outer edge 1111 of the mounting section 111 and the inner surface 5201 of the radio wave absorbing wall 520.

[0080] FIG. 21 is a top view of an RF tag reader 5A, which is a first modified example of the RF tag reader 5 according to the fourth embodiment of the present invention. The RF tag reader 5A has a reading unit 500A and a control unit 200 (not shown). The reading unit 500A has an upper portion 510A, a radio wave absorbing wall 520A, a bottom portion (not shown), and an antenna 131 (not shown). The upper portion 510A has a mounting portion 111 and a prohibition portion 512A. The radio wave absorbing wall 520A is composed of a flat plate on the left side, a flat plate on the back, and a flat plate on the right side. The flat plate on the left side, the flat plate on the back, and the flat plate on the right side each stand vertically from the bottom and are arranged in contact with part of the outer edge of the upper portion 510A. Accordingly, the shape of the prohibition portion 512A is different from the shape of the prohibition portion 512. The upper end of the radio wave absorbing wall 520A is higher than the upper surface of the upper portion 510A, which is the same as that of the radio wave absorbing wall 520 included in the RF tag reader 5. Here, the upper surface of the upper portion 510A is the upper surface of the prohibition portion 512A. In other respects, the configuration of the RF tag reader 5A is the same as that of the RF tag reader 5.

[0081] FIG. 22 is a top view of an RF tag reader 5B, which is a second modified example of the RF tag reader 5 according to the fourth embodiment of the present invention. The RF tag reader 5B includes a reader unit 500B and a controller 200 (not shown). The reader unit 500B includes an upper portion 510B, a radio wave absorbing wall 520B, a bottom portion (not shown), and an antenna 131 (not shown). The upper portion 510B includes a mounting portion 111 and a prohibition portion 512B. The radio wave absorbing wall 520B is identical to the radio wave absorbing wall 520 included in the RF tag reader 5 in that it is composed of an arc portion and two protrusions and its upper end is higher than the upper surface of the upper portion 510B. However, the cross section of the arc portion of the radio wave absorbing wall 520B is a quadrant arc, and the cross section of the radio wave absorbing wall 520B is substantially L-shaped. Accordingly, the shape of the prohibition portion 512B differs from that of the prohibition portion 512. The upper surface of the upper portion 510B is the upper surface of the prohibition portion 512B. Except for these points, the configuration of the RF tag reader 5B is the same as the configuration of the RF tag reader 5.

[0082] Fig. 23 is a top view of an example of an RF tag reader 6 according to a fifth embodiment of the present invention. Fig. 24 is a cross-sectional view taken along line GG in Fig. 23. The RF tag reader 6 has a reading unit 500 and a control unit 210. The reading unit 500 is the same as the reading unit 500 of the RF tag reader 4 according to the fourth embodiment. The control unit 210 is the same as that of the RF tag reader 3 according to the second embodiment.

[0083] The radio wave output of the antenna 131 in the RF tag reader 6 according to the fifth embodiment is greater than that of the RF tag reader 4 according to the fourth embodiment. In the RF tag reader 6, the RF tags 301 around the upper portion 510 may operate and transmit response radio waves. However, due to the gap between the outer edge 1111 of the mounting portion 111 and the outer edge 5122 of the prohibited portion 512, and the presence of the radio wave absorbing wall 520, a difference occurs between the strength of the radio waves radiated by the antenna 131 and reaching the mounting portion 111 and the strength of the radio waves radiated by the antenna 131 and reaching the periphery of the upper portion 510. This makes it possible for the RF tag reader 6 to determine whether the RF tag 301 is on the mounting portion 111 or around the upper portion 510, as will be described below.

[0084] The distance between the outer edge 1111 of the mounting section 111 and the outer edge 5122 of the prohibited section 512 is larger on the front side than on the back side. On the front side, the radio waves radiated from the antenna 131 are attenuated to an intensity at which the discrimination unit 212 can determine that the RF tag 301 is present around the upper part 510 when they reach the outer edge 5122 of the prohibited section 512. That is, the transceiver 210 causes the antenna 131 to radiate radio waves toward the front side at an intensity at which the discrimination unit 212 can determine that the RF tag 301 is present around the upper part 510 when they reach the outer edge 5122 of the prohibited section 512. Moreover, no RF tag 301 is present above the prohibited section 512. There is a large difference between the strength of the radio waves above the mounting section 111 and the strength of the radio waves leaking around the upper part 510. The strength of the radio waves above the mounting section 111 is much greater than the strength of the radio waves leaking around the upper part 510. The determination unit 212 can easily determine whether the RF tag 301 is on the placement unit 111 or whether the RF tag 301 is around the upper portion 510 .

[0085] On the other hand, on the back side, the radio waves radiated from the antenna 131 are attenuated by the time they reach the forbidden section 512. Then, by the time they reach the upper end of the radio wave absorbing wall 520, they are further attenuated. The radio waves are diffracted at the upper end of the radio wave absorbing wall 520, generating diffracted waves. The intensity of the diffracted waves is even weaker than the intensity of the radio waves reaching the upper end of the radio wave absorbing wall 520. The discrimination unit 212 can easily discriminate whether the RF tag 301 is on the mounting section 111 or is located around the upper part 510. In the RF tag reading device 6, because there is a gap between the outer edge 1111 of the mounting section 111 and the outer edge 5122 of the forbidden section 512, and because there is the radio wave absorbing wall 520, the intensity of the radio waves radiated from the antenna 131 and reaching the mounting section 111 is equal to or greater than a predetermined intensity. Therefore, the radio waves radiated from the antenna 131 and reaching the periphery of the upper part 510 are strong enough to allow the discrimination unit 212 to discriminate that the RF tag 301 is located around the upper part 510.

[0086] For example, when the longitudinal direction of the antenna of the RF tag 301 is nearly perpendicular to the main surface of the antenna 131 or when multiple RF tags 301 are overlapped, the radio waves received by the antenna of the RF tag 301 are weakened. However, the strength of the radio waves radiated from the antenna 131 toward the mounting unit 111 is strong. Therefore, the RF tag 301 attached to the article 300 placed on the upper surface of the mounting unit 111 operates, and information about the RF tag 301 attached to the article 300 placed on the upper surface of the mounting unit 111 can be obtained. There is little possibility that the transmitting / receiving unit 211 fails to read information from the RF tag 301 placed on the upper surface of the mounting unit 111.

[0087] On the other hand, the strength of the radio waves radiated from antenna 131 toward prohibited section 512 is weak. If an RF tag 301 is placed on the top surface of prohibited section 512, and the longitudinal direction of the antenna of RF tag 301 is nearly perpendicular to the main surface of antenna 131 or if multiple RF tags 301 are overlapping, the strength of the radio waves received by RF tag 301 will be weak, and discrimination unit 212 may determine that RF tag 301 is located near upper portion 510. However, RF tag 301 is not placed on the top surface of prohibited section 512. The radio waves radiated by antenna 131 and reaching the periphery of upper portion 510 have an intensity that allows discrimination unit 212 to determine that RF tag 301 is located near upper portion 510, and therefore transceiver unit 211 can exclude RF tags 301 located near upper portion 510 from targets for reading information.

[0088] Furthermore, stores usually have ceilings. When the RF tag reader 6 is used in a store, the radio waves emitted from the antenna 131 may reflect off the ceiling and reach RF tags 301 around the upper part 510 (i.e., RF tags 301 that are not above the upper part 510). However, the radio waves are attenuated before they reach the ceiling, and the reflected waves reflected off the ceiling are further attenuated before they reach RF tags 301 around the upper part 510. The radio waves that are emitted upward by the antenna 131, reflected off the ceiling, and reach RF tags 301 around the upper part 510 have an intensity that allows the discrimination unit 212 to discriminate that RF tag 301 as being around the upper part 510.

[0089] Therefore, the RF tag reading device 6 is less likely to fail to read information from the RF tag 301 placed on the top surface of the mounting section 111, and can prevent erroneous reading of information from the RF tag 301 around the upper part 510.

[0090] The diffracted waves generated at the upper end of the radio wave absorbing wall 520 must be attenuated to an intensity that allows the discrimination unit 212 to discriminate that an RF tag 301 that has received the diffracted waves and been activated is present around the upper portion 510. In the RF tag reading device 6, there is a gap between the outer edge 1111 of the mounting unit 111 and the inner surface 5201 of the radio wave absorbing wall 520 on the back side. The radio waves radiated from the antenna 131 are attenuated when they reach the prohibition portion 512. Then, these radio waves are further attenuated when they reach the upper end of the radio wave absorbing wall 520. For this reason, the height of the radio wave absorbing wall 520 can be lowered depending on the gap between the outer edge 1111 of the mounting unit 111 and the inner surface 5201 of the radio wave absorbing wall 520.

[0091] Like the RF tag reading device 5 according to the fourth embodiment, the RF tag reading device 6 according to the fifth embodiment can be configured to have a reading unit 500A and a control unit 210 shown in FIG. 21, or a reading unit 500B and a control unit 210 shown in FIG. 22, instead of the reading unit 500.

[0092] FIG. 25 is a top view of an RF tag reader 7, which is a comparative example of the RF tag reader 5 according to the fourth embodiment. The RF tag reader 7 has a reading unit 600 and a control unit 200 (not shown). The reading unit 600 has an upper portion 610, a radio wave absorbing wall 620, a bottom portion (not shown), and a bottom antenna 131 (not shown). The upper portion 610 has a mounting portion 111 and a prohibition portion 612. Unlike the radio wave absorbing wall 520 included in the RF tag reader 5 according to the fourth embodiment, the radio wave absorbing wall 620 consists only of an arc portion and does not have two protrusions. Accordingly, the shape of the prohibition portion 612 is different from the shape of the prohibition portion 512. In other respects, the configuration of the RF tag reader 7 is the same as that of the RF tag reader 5.

[0093] 25, in the RF tag reader 7 of the comparative example, the radio waves radiated from the bottom antenna 131 are diffracted at both ends of the arcuate portion of the radio wave absorbing wall 620 to generate diffracted waves, which are relatively strong. Therefore, these diffracted waves may activate the RF tags 301 around the upper part 610. On the other hand, the diffracted waves generated at the tips of the two protrusions in the radio wave absorbing wall 520 of the RF tag reader 5 according to the fourth embodiment are weak. Therefore, in the RF tag reader 5, the RF tags 301 around the upper part 510 do not activate.

[0094] In the above-described embodiment, each RF tag reader and RF tag communicate using radio waves in the UHF band with a frequency of 860 to 960 MHz, but this is not limited to this, and each RF tag reader and RF tag may also communicate using radio waves of other frequencies.

[0095] Furthermore, in the above-described embodiments, products have been described as examples, but the items are not limited to products and may be other objects such as samples, documents, books, medicines, keys, etc. Furthermore, in the above-described embodiments, examples have been shown in which the RF tag readers according to the present invention are used in store cash registers and self-checkouts, but the present invention is not limited to this, and these RF tag readers can also be used for other purposes, such as management devices for samples, documents, books, medicines, keys, etc.

[0096] FIG. 26 shows an example of the configuration of a dual RF tag 700 including dual RF tags 711 and 715. FIG. 26(A) is a plan view of the dual RF tag 700. FIG. 26(B) is a front view of the dual RF tag 700. The dual RF tag 700 has an RF tag 711 and an RF tag 715. The RF tags 711 and 715 are passive RF tags. The main surfaces of the RF tags 711 and 715 are on the same plane. As can be seen from FIG. 26(B), the dual RF tag 700 is thin. The dual RF tag 700 is configured, for example, by sandwiching the RF tags 711 and 715 between thin, hard papers (e.g., cardboard) on the front and back sides. These thin, hard papers allow radio waves to pass through. The RF tags 711 and 715 do not overlap, but are arranged so that their longitudinal directions are perpendicular to each other. The RF tag 711 and the RF tag 715 are arranged, for example, in an L shape.

[0097] The RF tag 711 has an antenna 712 and an IC chip 713. The RF tag 711 communicates with an RFID reader / writer or the like using radio waves in the UHF band with a frequency of, for example, 860 to 960 MHz. When the antenna 712 receives radio waves emitted by the antenna of the RFID reader / writer or the like, power is generated. The IC chip 713 operates using this power. The IC chip 713 stores information including a unique tag ID that is determined so as to uniquely identify an item. The RF tag 711 transmits a response radio wave in response to the radio waves emitted by the antenna of the RFID reader / writer or the like. The response radio wave contains information including the tag ID.

[0098] RF tag 715 has an antenna 716 and an IC chip 717. IC chip 717 operates using power generated by radio waves received by antenna 716. RF tag 715 operates in the same manner as RF tag 711. IC chip 713 and IC chip 717 may store the same information, including a tag ID, or may store different tag IDs but the same information other than the tag ID. Furthermore, the information stored in IC chip 713 and the information stored in IC chip 717 may be different.

[0099] The longitudinal direction of antenna 712 and the longitudinal direction of antenna 716 are perpendicular to each other. Therefore, even if antenna 712 cannot receive radio waves, antenna 716 can receive radio waves, and RF tag 715 can transmit response radio waves. Similarly, depending on the orientation of the antenna of the RFID reader / writer or the like and the orientation of antenna 716, antenna 716 may not be able to receive radio waves, and RF tag 715 may not be able to transmit response radio waves. However, even if antenna 716 cannot receive radio waves, antenna 712 can receive radio waves, and RF tag 711 can transmit response radio waves.

[0100] 27 shows an example in which a duplicated RF tag 700 is placed on the placement section 111 of the RF tag reader 1 of FIG. The duplicated RF tag 700 is placed on the placement section 111 so that the longitudinal direction of the RF tag 711 is parallel to the surface of the antenna 131. At this time, the longitudinal direction of the RF tag 715 is perpendicular to the surface of the antenna 131. In this case, the acquisition section 202 cannot acquire information from the RF tag 715, but can acquire information from the RF tag 711.

[0101] FIG. 28 shows a dual RF tag 720, which is a different configuration from the dual RF tag 700 of FIG. 26. FIG. 28(A) is a plan view of the dual RF tag 720. FIG. 28(B) is a front view of the dual RF tag 720. The dual RF tag 720 has dual antennas 722 and 726, and an IC chip 723. The main surfaces of the antennas 722 and 726 are on the same plane. As can be seen from FIG. 28(B), the dual RF tag 720 is thin. The dual RF tag 720 is configured, for example, by sandwiching the antennas 722 and 726, and the IC chip 723 between thin, hard papers (e.g., cardboard) on the front and back sides. These thin, hard papers allow radio waves to pass through. The IC chip 723 is attached to the center of the antenna 722. The IC chip 723 stores information including the tag ID.

[0102] Antenna 722 and antenna 726 do not overlap, and are arranged so that their longitudinal directions are perpendicular to each other. Antenna 722 and antenna 726 are arranged, for example, in an L shape. The center of antenna 726 is connected to IC chip 723 by predetermined wiring 728. Dual RF tag 720 communicates with an RFID reader / writer, for example, using radio waves in the UHF band with a frequency of 860 to 960 MHz.

[0103] When at least one of antenna 722 and antenna 726 receives radio waves emitted by an antenna such as an RFID reader / writer, electric power is generated. For example, when antenna 726 receives radio waves emitted by an antenna such as an RFID reader / writer, electric power is generated. A portion of this electric power is supplied to IC chip 723 via wiring 728. IC chip 723 operates using this electric power. Information stored in IC chip 723 is transmitted to antenna 726 via wiring 728. Antenna 726 transmits a response radio wave containing this information. That is, antennas 722 and 726 transmit a response radio wave containing the information stored in IC chip 723.

[0104] 26 above shows an example in which the RF tags 711 and 715 are arranged in an L-shape so as not to overlap, but this is not limited to an L-shape, and it is sufficient that the RF tags 711 and 715 do not overlap and their longitudinal directions are orthogonal. Similarly, while the above-mentioned Fig. 28 shows an example in which the antennas 722 and 726 are arranged in an L-shape so as not to overlap, this is not limited to an L-shape, and it is sufficient that the antennas 722 and 726 do not overlap and their longitudinal directions are orthogonal.

[0105] In the above-described embodiment, an example of a dual RF tag has been shown in which the RF tags 711 and 715 are sandwiched between thin, hard paper (for example, cardboard) on the front and back sides, but the present invention is not limited to this, and may alternatively be configured such that the RF tags 711 and 715 are attached to a thin plastic plate or resin film. Similarly, the antennas 722 and 726 may alternatively be attached to a thin plastic plate or resin film.

[0106] Furthermore, in the example of the RF tag reading device described above, antenna 131 either emits circularly polarized radio waves or emits two linearly polarized radio waves that are orthogonal to each other while switching between them, but the dual RF tag of the present disclosure can of course be used in an RFID reader / writer or the like that has an antenna that emits linearly polarized radio waves.

[0107] The dual RF tag of the present disclosure can also be used for purposes other than the RF tag reader described above. For example, it can be used in a location information acquisition system in a building with multiple rooms, in which an RFID reader / writer antenna is installed on the ceiling or other surface of each room. When each person in the building wears the dual RF tag of the present disclosure, the location information acquisition system can acquire the location information of each person.

[0108] As described above, according to the present invention, it is possible to reduce the possibility of failing to read information from an RF tag from which information is to be acquired, prevent erroneous reading of information from RF tags surrounding the RF tag reader, and improve ease of use. For example, the RF tag readers 1 to 4 according to the first to third embodiments do not have a radio wave absorbing wall, so that articles and shopping baskets can be easily placed on the placing section 111. Furthermore, for example, the RF tag reader 5 according to the fourth embodiment and the RF tag reader 6 according to the fifth embodiment have a low radio wave absorbing wall, so that articles and shopping baskets can be easily placed on the placing section 111.

[0109] Although the embodiments of the present invention have been described above, various modifications and combinations that may be required due to convenience in design or manufacturing or other factors are included within the scope of the invention described in the claims and the invention corresponding to the specific examples described in the embodiments of the invention. [Explanation of symbols]

[0110] 1, 2, 3, 4, 5, 5A, 5B, 6... RF tag reader, 7... RF tag reader of comparative example, 100, 101... reading unit, 110... upper part, 111... placing unit, 1111... outer edge of placing unit 111, 112, 112A, 112B, 112C... prohibited unit, 1121... inner edge of prohibited unit 112, 1122... outer edge of prohibited unit 112, 1121A... inner edge of prohibited unit 112A, 1122A... outer edge of prohibited unit 112A Edge, 1121B...inner edge of prohibition portion 112B, 1122B...outer edge of prohibition portion 112B, 1121C...inner edge of prohibition portion 112C, 1122C...outer edge of prohibition portion 112C, 120, 121...side portion, 130...bottom portion, 131...antenna, 200, 210...control portion, 201, 211...transmitting / receiving portion, 202, 213...acquisition portion, 203, 214...I / F (interface), 212...discrimination portion, 300...article, 301...RF tag, 302...shopping basket, 400...base, 410...top of base, 411...hole in top of base, 420...bottom of base, 430...front of base, 431...left side of base, 432...right side of base, 500, 500A, 500B...reading unit, 510, 510A, 510B...upper part, 512, 512A, 512B...prohibited part, 5121...inner edge of prohibited part 512, 5122...of prohibited part 512 Outer edge, 520, 520A, 520B... radio wave absorbing wall, 5201... inner surface of radio wave absorbing wall 520, 530... bottom, 600... reading section of comparative example, 610... upper part of comparative example, 612... prohibition section of comparative example, 620... radio wave absorbing wall of comparative example, 700, 720... dual RF tag, 711, 715... RF tag, 712, 716, 722, 726... antenna, 713, 717, 723... IC chip, 728... wiring

Claims

1. an upper portion made of a material that transmits radio waves and having a mounting portion on which an article having a passive RF tag attached is placed, and an upper portion made of a material that transmits radio waves and surrounding the mounting portion, having a prohibition portion where placing an RF tag is prohibited, with a gap between the outer edge of the mounting portion and the outer edge of the prohibition portion; an antenna for communicating with the RF tag, the antenna being located below the placement portion and positioned to radiate radio waves with high intensity toward the placement portion and to radiate radio waves with an intensity lower than that radiated toward the placement portion toward the prohibition portion; Equipped with By providing a gap between the outer edge of the placement section and the outer edge of the prohibition section, it is possible to reduce the possibility of failing to read information from an RF tag attached to an item placed on the top surface of the placement section and to prevent erroneous reading of information from RF tags around the upper part. RF tag reader.

2. The RF tag reading device described in claim 1, wherein by providing a gap between the outer edge of the placement section and the outer edge of the prohibition section, the strength of the radio waves emitted by the antenna and reaching the placement section can be made to be equal to or greater than a predetermined strength, and the radio waves emitted by the antenna and reaching the area around the upper portion can be made to be of a strength that will not cause the RF tag to operate.

3. The RF tag reading device described in claim 1, wherein a gap exists between the outer edge of the placement section and the outer edge of the prohibition section, which creates a difference in the strength of the radio waves radiated by the antenna and reaching the placement section and the strength of the radio waves radiated by the antenna and reaching the surrounding area of ​​the upper section, making it possible to determine whether an RF tag is on the placement section or around the upper section.

4. The mounting portion is circular, the polarization method of the radio waves radiated by the antenna is circular polarization, and the center of a radiation area of ​​the antenna that radiates the radio waves is located directly below the center of the mounting portion; The RF tag reader according to claim 1 .

5. an electromagnetic wave absorbing wall having an inner surface in contact with a part of an outer edge of the upper portion, extending above and below the upper portion, and absorbing electromagnetic waves; The presence of a gap between the outer edge of the placement section and the outer edge of the prohibition section, and the presence of the radio wave absorbing wall, reduces the possibility of failing to read information from an RF tag attached to an item placed on the top surface of the placement section, and makes it possible to prevent erroneous reading of information from RF tags around the upper portion. The RF tag reader according to claim 1 .

6. The RF tag reading device described in claim 5, wherein the strength of the radio waves radiated by the antenna and reaching the placement section can be made to be equal to or greater than a predetermined strength due to the presence of a gap between the outer edge of the placement section and the outer edge of the prohibition section, and the strength of the radio waves radiated by the antenna and reaching the periphery of the upper section can be made to be such that the RF tag does not operate.

7. The RF tag reading device described in claim 5, wherein the presence of a gap between the outer edge of the placement section and the outer edge of the prohibition section, and the presence of the radio wave absorbing wall, creates a difference in the strength of the radio waves radiated by the antenna and reaching the placement section and the strength of the radio waves radiated by the antenna and reaching the surroundings of the upper section, making it possible to determine whether an RF tag is on the placement section or around the upper section.

8. The mounting portion is circular, the polarization method of the radio waves radiated by the antenna is circular polarization, and the center of a radiation area of ​​the antenna that radiates the radio waves is located directly below the center of the mounting portion; The RF tag reader according to claim 5 .

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