RF tag reader

Abstract

To reduce the possibility of failing to read information from an RF tag that is a target for acquiring information, to prevent erroneous reading of information from RF tags around an RF tag reader, and to improve ease of use. [Solution] The upper part 110 has 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. An article 300 with an RF tag 301 attached is placed on the upper surface of the placement portion 111. The prohibition portion 112 surrounds the periphery of the placement portion 111. There is a gap between an outer edge 1111 of the placement portion 111 and an outer edge 1122 of the prohibition portion 112. Placing the RF tag 301 on the prohibition portion 112 is prohibited. An antenna for communicating with the RF tag 301 is provided under the placement portion 111. The antenna radiates radio waves with a high intensity toward the placement portion 111, and radiates radio waves with a lower intensity than the radio waves radiated toward the placement portion 111 toward the prohibition portion 112.

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, when an RFID reader / writer antenna emits circularly polarized radio waves, if the radio waves emitted from the RFID reader / writer antenna are weak and the longitudinal direction of the RF tag antenna is nearly perpendicular to the surface of the RFID reader / writer antenna, the RF tag may not function and may not be able to transmit information in response to the received radio waves. It is also known that the strength of the radio waves received by each RF tag is weakened when multiple RF tags are overlapped.

[0003] Meanwhile, RF tags used for apparel inventory, incoming and outgoing 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. It is known that at such a relatively low frequency, 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 that has an opening at the top of a storage section and acquires information from a passive RF tag inside the storage section when the opening is open. The left side, rear, and right side sections each include an electromagnetic wave absorbing layer and are higher than the front section. The inside of the storage section 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 rear section. Here, the storage space can store an item with an RF tag attached, but the attenuation space cannot store an item. The bottom antenna is installed on the top surface of the bottom section at a position that radiates a radio wave with a high intensity toward the storage space and radiates a radio wave with a lower intensity than the radio wave radiated toward the storage space toward the attenuation space.

[0005] In the RF tag reader described in Patent Document 1, the radio waves radiated from the bottom antenna are significantly attenuated when they reach the upper ends of the left side, rear, and right side. Radio waves radiated from the bottom antenna toward the front of the storage unit are significantly attenuated while propagating through the attenuation space. This RF tag reader can therefore reduce the possibility of failing to read information from an RF tag stored in the storage unit, and can prevent erroneous acquisition of information from an RF tag outside the storage unit due to diffraction of radio waves 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 of the RF tag reader described in Patent Document 1 must be at a height that can prevent radio waves radiated upward from the bottom antenna from diffracting at the periphery of the opening when they reach the upper end of the housing, resulting in erroneous acquisition of information from an RF tag outside the housing. For this reason, 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 obtained, 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, which is made of a material that transmits radio waves and has a placement section on which an article having a passive RF tag attached thereto is placed, and which is also made of a material that transmits radio waves and has a prohibition section that surrounds the placement section and on which it is prohibited to place an RF tag, with a gap between the outer edge of the placement section and the outer edge of the prohibition section; an antenna for communicating with the RF tag, the antenna being located under the placement portion and arranged at a position where it radiates radio waves with a high intensity toward the placement portion and radiates radio waves with a lower intensity than the radio waves radiated toward the placement portion toward the prohibition portion; Equipped with By providing a gap between the outer edge of the mounting portion and the outer edge of the prohibition portion, it is possible to reduce the possibility of failing to read information from an RF tag attached to an item placed on the upper surface of the mounting portion and to prevent erroneous reading of information from RF tags around the upper portion.

[0010] Preferably, the RF tag reader of the present invention comprises: By providing a gap between the outer edge of the mounting portion and the outer edge of the prohibition portion, the strength of the radio waves radiated by the antenna and reaching the mounting portion can be made to be equal to or greater than a predetermined strength, and the strength of the radio waves radiated by the antenna and reaching the periphery of the upper portion can be made to be such that the RF tag will not operate.

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

[0012] Preferably, the RF tag reader of the present invention comprises: The placement portion is circular, The polarization type 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.

[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; By providing a gap between the outer edge of the mounting portion and the outer edge of the prohibition portion, and by providing the radio wave absorbing wall, it is possible to reduce the possibility of failing to read information from an RF tag attached to an item placed on the upper surface of the mounting portion and to prevent erroneous reading of information from RF tags around the upper portion.

[0014] Preferably, the RF tag reader of the present invention comprises: Due to the presence of a gap between the outer edge of the mounting portion and the outer edge of the prohibition portion, and the presence of the radio wave absorbing wall, the strength of the radio waves radiated by the antenna and reaching the mounting portion can be made to be above a predetermined strength, and the strength of the radio waves radiated by the antenna and reaching the periphery of the upper portion can be made to be such that the RF tag will not operate.

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

[0016] Preferably, the RF tag reader of the present invention comprises: The placement portion is circular, The polarization type 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. Effect of the Invention

[0017] 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 obtained, to prevent erroneous reading of information from RF tags surrounding the RF tag reader, and to improve ease of use. [Brief description 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. [Diagram 2] FIG. 2 is a top view of the RF tag reader of FIG. [Diagram 3] 2 is a cross-sectional view taken along line AA in FIG. 1. [Figure 4] 3 is a diagram showing an example of radio waves radiated from an antenna in the RF tag reader according to the first embodiment. FIG. [Diagram 5] 1. FIG. 4 is a diagram showing a prohibition unit which 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 which is a second modified example of the prohibition unit in the RF tag reader of FIG. [Figure 7] 1 is a top view of an RF tag reader which is a modified example of the RF tag reader according to the first embodiment. FIG. [Figure 8] 8 is a cross-sectional view taken along line BB in FIG. 7. [Figure 9] 8 is a cross-sectional view taken along line CC in FIG. 7. [Figure 10] FIG. 11 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 line DD in FIG. [Figure 12] 13 is a diagram showing an example of radio waves radiated from an antenna in an RF tag reader according to a second embodiment. FIG. [Figure 13] FIG. 11 is a perspective view of an example of an RF tag reader according to a third embodiment of the present invention. [Figure 14] 14 is a cross-sectional view taken along line EE in FIG. 13. [Figure 15] 13 is a diagram showing an example of radio waves radiated from an antenna in an RF tag reader according to a third embodiment. FIG. [Figure 16] FIG. 13 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. 16. [Figure 18] FIG. 17 is a side view of the RF tag reader of FIG. 16. [Figure 19] 17 is a cross-sectional view taken along the line FF in FIG. 16. [Figure 20] FIG. 13 is a diagram showing an example of radio waves radiated from an antenna in an RF tag reader according to a fourth embodiment. [Figure 21] FIG. 13 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. [Diagram 23] FIG. 13 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. [Diagram 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 illustrating 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] Fig. 28 shows a dual RF tag which is a different configuration example from the dual RF tag shown in Fig. 26. Fig. 28(A) is a plan view of the dual RF tag. Fig. 28(B) is a front view of the dual RF tag. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[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 explaining the embodiment, the same components are given the same reference numerals, and the 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 in a store or a self-checkout operated by a customer. The RF tag reader 1 has a reading unit 100 and a control unit 200. The reading unit 100 has an upper portion 110, a side portion 120, a bottom portion 130, and an antenna 131.

[0021] The upper portion 110 has a placement portion 111 and a prohibition portion 112. The placement portion 111 is made of a material that transmits radio waves. The material that transmits radio waves is, for example, wood, but may be other materials. The placement portion 111 has a shape according to the polarization method of the radio waves radiated by the antenna 131. When the polarization method of the radio waves radiated by the antenna 131 is, for example, circular polarization, the placement portion 111 is a circular flat plate. However, in this case, the shape of the placement 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 to which a passive RF tag 301 is attached is placed on the upper surface of the placement portion 111. The item 300 is, for example, a commodity. The item 300 is contained inside a shopping basket 302, and the shopping basket 302 may be placed on the upper surface of the placement portion 111.

[0022] The RF tag 301 is used, for example, for 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 inventory management (inspection and inventory) of products in factories, inspection and inventory of products 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, for example, 860 to 960 MHz. 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 forbidden part 112 is made of a material that transmits radio waves. The forbidden part 112 is, for example, annular. The inner edge 1121 of the forbidden part 112 is in contact with the outer edge 1111 of the placement part 111, and surrounds the placement part 111. There is a gap between the outer edge 1111 of the placement part 111 and the outer edge 1122 of the forbidden part 112. It is prohibited to place an article on the forbidden part 112. The RF tag 301 cannot be placed on the forbidden part 112. As shown in FIG. 3, the cross-sectional shape of the forbidden part 112 is, for example, L-shaped. The forbidden part 112 is composed of a parallel part that is parallel to the placement part 111 and a vertical part that is perpendicular to the placement part 111. The upper end of the vertical part is fixed to the inner edge of the parallel part. The lower end of the vertical part is fixed to, for example, the outer edge 1111 of the placement part 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] Note that placement portion 111 and prohibition portion 112 may be present on the same plane. In this case, prohibition portion 112 has no vertical portion. In this configuration, it is desirable to provide a mark on the upper surface of upper portion 110 so that placement portion 111 and 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 portion of the prohibited portion 112 (i.e., the outer edge 1122 of the prohibited portion 112). The side portion 120 is made of a material that is transparent to radio waves.

[0026] The bottom 130 is, for example, a circular flat plate. The bottom 130 may be made of only 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 radiates radio waves for communicating with the RF tag 301 upward, 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 radiates a circularly polarized radio wave, or radiates two linearly polarized radio waves whose polarization directions are orthogonal to each other while switching between them. The horizontally polarized wave and the vertically polarized wave are examples of two linearly polarized radio waves whose polarization directions are orthogonal to each other. The antenna 131 is located under the placement unit 111. The radio waves radiated from antenna 131 propagate while spreading upward. Antenna 131 is installed at a position where it radiates radio waves with a high intensity toward mounting portion 111 and radiates radio waves with a lower intensity than the radio waves radiated toward mounting portion 111 toward prohibited portion 112. When antenna 131 radiates circularly polarized radio waves, it is desirable to install it 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 transmission / reception unit 201, an acquisition unit 202, and an I / F (interface) 203. The transmission / reception unit 201 causes the antenna 131 to radiate a circularly polarized radio wave, or causes the antenna 131 to radiate 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 transmission / reception 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 less 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 in the range of the diagonal dashed line slanting upward to the right operates. 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 1122 of the prohibited section 112. That is, the transmitting / receiving unit 201 causes the antenna 131 to emit radio waves of an intensity at which the RF tag 301 does not operate when they reach the outer edge 1122 of the prohibited section 112. In the RF tag reader 1, since 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 are of an intensity at which the RF tag 301 does not operate.

[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 placement unit 111 is strong. Therefore, the RF tag 301 attached to the article 300 placed on the upper surface of the placement unit 111 operates, and the information of the RF tag 301 attached to the article 300 placed on the upper surface of the placement unit 111 can be obtained. There is a low possibility that the transmitting / receiving unit 201 will miss reading the information from the RF tag 301 placed on the upper surface of the placement unit 111.

[0031] On the other hand, the strength of the radio waves radiated from antenna 131 toward prohibited portion 112 is low. If RF tag 301 is placed on the upper surface of prohibited portion 112, there is a risk that RF tag 301 will 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 overlapped. In other words, there is a possibility that transceiver unit 201 will not read information from that RF tag 301. However, RF tag 301 is not placed on the upper surface of prohibited portion 112. Since the radio waves radiated by antenna 131 and reaching the periphery of upper portion 110 are of such strength that RF tag 301 will not function, transceiver unit 201 can exclude RF tags 301 around upper portion 110 from targets for reading information.

[0032] Furthermore, a store usually has a ceiling. When the RF tag reader 1 is used in a store, radio waves radiated from the antenna 131 may be reflected by the ceiling and reach the RF tags 301 around the upper part 110 (i.e., the 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 reflected by the ceiling are further attenuated before they reach the RF tags 301 around the upper part 110. The transmitting / receiving unit 201 causes the antenna 131 to radiate radio waves of an intensity that causes the RF tags 301 around the upper part 110 to not operate due to the radio waves reflected by the ceiling.

[0033] If the RF tag 301 is not in operation, it will not transmit any response radio waves, and therefore the RF tag reader 1 will not obtain information about 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 upper surface of the placement unit 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 operating 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 from which the antenna 131 emits 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] In addition, in the above-described first embodiment, an example was shown in which the mounting portion 111 was a circular flat plate, but this is not limited thereto, and the mounting portion 111 may have any other shape, for example, 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 portion 112A which is a first modified example of the prohibition portion 112 in the RF tag reader 1 of FIG. 1. The cross-sectional shape of the prohibition portion 112A is composed 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 portion 111. The side of the vertical portion that is fixed to the outer edge 1111 is the inner edge 1121A of the prohibition portion 112A. The other end of the arc portion is fixed to the upper end of the side portion 120. The other end side of the arc portion is the outer edge 1122A of the prohibition portion 112A. The placement portion 111 is recessed with respect to the prohibition portion 112A. The cross-sectional shape composed 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 article.

[0039] FIG. 6 shows a prohibition portion 112B which is a second modified example of the prohibition portion 112 in the RF tag reader 1 of FIG. The cross-sectional shape of the prohibition portion 112B is a circular arc portion of a sector with a central angle of 180 degrees or less. One end of the circular arc portion is fixed to the outer edge 1111 of the placement portion 111. One end side of the circular arc portion is an inner edge 1121B of the prohibition portion 112B. The other end of the circular arc portion is fixed to the upper end of the side portion 120. The other end side of the circular arc portion is an outer edge 1122B of the prohibition portion 112B. The placement portion 111 is recessed with respect to the prohibition portion 112B. The circular arc portion of a sector with a central angle of 180 degrees or less is another example of a shape that makes it difficult to place an article 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 stand 400, and an upper portion 110, a control unit 200, and an 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. The top surface 410 of the stand 400 has a hole 411. The upper portion 110 of the RF tag reader 1 according to the first embodiment is attached to the hole 411. For example, an accounting device or the like can be installed in the area of ​​the top surface 410 of the stand 400 excluding the upper portion 110. Also, a customer can put purchased products into 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. The prohibited portion 112 is composed of a parallel portion and a vertical portion, but the prohibited portion 112C has a first vertical portion fixed to the inner edge of the parallel portion and a second vertical portion fixed to the outer edge of the parallel portion. The first vertical portion side of the prohibited portion 112C is the inner edge 1121C of the prohibited portion 112C, and the second vertical portion side is the outer edge 1122C of the prohibited portion 112C. This makes the cross-sectional shape of the prohibited portion 112C convex. The prohibited portion 112C protrudes upward from the upper surface portion 410 of the base 400. The placement portion 111 is recessed with respect to the prohibited portion 112C.

[0043] The control unit 200 is installed, for example, on the upper surface of the bottom surface unit 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 placement unit 111 and radiates radio waves with an intensity lower than that of the radio waves radiated toward the placement unit 111 toward the prohibition unit 112C. When the antenna 131 radiates circularly polarized radio waves, it is desirable to install the antenna 131 so that the center of the area where the radio waves are radiated is located directly below the center of the placement unit 111. Note that the antenna 131 may be installed on the upper surface of the bottom surface unit 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 larger 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, the RF tag 301 that receives radio waves in the range of the diagonal dashed line slanting upward to the right operates. This range extends outside the outer edge 1122 of the prohibited portion 112. For this reason, the RF tag 301 around the upper portion 110 may operate and transmit a response radio wave. However, since there is a gap between the outer edge 1111 of the placement portion 111 and the outer edge 1122 of the prohibited portion 112, a difference occurs between the strength of the radio waves radiated by the antenna 131 to reach the placement portion 111 and the strength of the radio waves radiated by the antenna 131 to reach the periphery of the upper portion 110. This enables the RF tag reader 3 to determine whether the RF tag 301 is on the placement portion 111 or around the upper portion 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 causes the antenna 131 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 transceiver 211 acquires information including the RSSI and the 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 radiated 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 discriminates whether the RF tag 301 from which the RSSI was acquired is located around the upper part 110 or on the placement unit 111 (i.e., on the upper part 110). For example, when 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 discriminates that the RF tag 301 is located on the placement unit 111. On the other hand, when 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 discriminates 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 transmitting / receiving unit 211 acquires information including the strength of the response radio wave and the tag ID from the response radio wave. The determining unit 212 determines whether the RF tag 301 from which the strength of the response radio wave is acquired is located around the upper part 110 or on the placement unit 111 based on the strength of the response radio wave acquired from the response radio wave received by the antenna 131. For example, the determining unit 212 determines that the RF tag 301 is located on the placement unit 111 when the strength 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 determining unit 212 determines that the RF tag 301 is located around the upper part 110 when the strength 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 FIG. 12, there is a possibility that the RF tag 301 around the upper part 110 may 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 part 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 on the prohibited part 112. There is a large difference between the strength of the radio waves leaking around the upper part 110 and the strength of the radio waves above the placement part 111. The strength of the radio waves above the placement part 111 is much greater than the strength of the radio waves leaking around the upper part 110. There is a low possibility that the transceiver 211 will fail to read information from the RF tag 301 placed on the top surface of the placement part 111.

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

[0052] Furthermore, a store usually has a ceiling. When the RF tag reader 3 is used in a store, the radio waves emitted from the antenna 131 may be reflected by the ceiling and reach the RF tag 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 tag 301 around the upper part 110. When the RF tag 301 around the upper part 110 is activated by the reflected waves and transmits a response radio wave, the response radio wave 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 tag 301 from which the RSSI or the response radio wave intensity was acquired is around the upper part 110, based on the RSSI or the intensity of the response radio wave acquired from the response radio wave received by the antenna 131. In the RF tag reading device 3, the transmitter / receiver unit 211 causes the antenna 131 to radiate 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 from 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, due to the presence of a gap between the outer edge 1111 of the mounting 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 article 300 placed on the upper surface of the mounting section 111, excluding the RF tags 301 around the upper part 110. The RF tag reading device 3 reduces the possibility of failing to read information from the RF tag 301 placed on the upper surface of the mounting section 111, and can prevent erroneous reading of information from the RF tags 301 around the upper part 110.

[0054] For example, when the discrimination unit 212 discriminates that the RF tag 301 is on the placement 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 the RF tag 301, the RF tag reader 3 can distinguish between the RF tag 301 on the placement unit 111 and the RF tags 301 around the upper portion 110 and acquire information from the RF tag 301 on the placement unit 111.

[0055] The I / F 214 transmits the information acquired by the acquisition unit 213 to an external device (for example, an accounting device, etc.) 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 together with information indicating whether the RF tag 301 is located on the placement unit 111 or around the upper part 110.

[0057] Moreover, 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 having a base 400, an upper portion 110, the control portion 210 of the RF tag reader 2 according to the second embodiment, and an antenna 131. However, in this configuration, the top surface portion 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 side portion may be configured so that all or part of the inner surface thereof is covered with a radio wave absorbing layer. Figures 13 to 15 show an example of an RF tag reader 4 which is a modification of the RF tag reader 1 according to the first embodiment and 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 the third embodiment of the present invention. FIG. 14 is a cross-sectional view taken along the line EE in FIG. 13. The RF tag reader 4 includes a reader 101 and a controller 200. The reader 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 is different 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 reader 101 and the configuration of the reader 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 be configured such that a radio wave reflection 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 reflection sheet. The radio wave absorbing sheet is, for example, a sheet made of a material in which magnetic metal powder is mixed into a rubber material. 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 radiated from the antenna 131 in the RF tag reader 4 according to the third embodiment. As shown in Fig. 15, when the radio waves radiated 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 slanting 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 portion 112. The intensity of the diffracted waves is even smaller than the intensity of the radio waves that reach the outer edge 1122 of the prohibited portion 112. There is a large difference between the intensity of the diffracted waves and the intensity of the radio waves above the mounting portion 111. The intensity of the radio waves above the mounting portion 111 is much greater than the intensity of the diffracted waves. There is a low possibility that the transceiver 211 will fail to read information from the RF tag 301 placed on the top surface of the mounting portion 111. On the other hand, in the RF tag reader 4, the intensity of the diffracted waves is small, and the RF tags 301 around the upper portion 110 will not function. In the RF tag reading device 4, since 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 wave radiated by the antenna 131 and reaching the placement section 111 is equal to or greater than a predetermined strength, and the radio wave radiated by the antenna 131 and reaching the periphery of the upper section 110 is of such strength that the RF tag 301 does not operate. If the RF tag 301 exists on the prohibited section 112, the RF tag 301 may operate and transmit a response radio wave when it receives the radio wave radiated from the antenna 131, but the RF tag 301 does not exist on the prohibited section 112. In the RF tag reading device 4, the RF tag 301 attached to the article 300 placed on the upper surface of the placement section 111 operates, and the transmitting / receiving unit 201 can obtain information of the RF tag 301. On the other hand, the RF tags 301 around the upper section 110 do not operate, so the transmitting / receiving unit 201 can exclude the RF tags 301 around the upper section 110 from the targets for reading information.

[0063] Furthermore, a store usually has a ceiling. When the RF tag reader 4 is used in a store, the radio waves radiated from the antenna 131 may be reflected by the ceiling and reach the RF tags 301 around the upper part 110 (i.e., the 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 reflected by the ceiling are further attenuated before they reach the RF tags 301 around the upper part 110. The transmitting / receiving unit 201 causes the antenna 131 to radiate radio waves of an intensity that causes the RF tags 301 around the upper part 110 to not operate due to the radio waves reflected by the ceiling.

[0064] If the RF tag 301 is not in operation, it will not transmit any response radio waves, and therefore the RF tag reader 4 will not acquire information about the RF tags 301 around the upper portion 110. Therefore, the RF tag reader 4 is less likely to fail to read information from the RF tags 301 placed on the upper surface of the placement section 111, and can prevent erroneous reading of information from the RF tags 301 around the upper portion 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 an outer edge 5122 of the prohibition portion 512. Placing the RF tag 301 on the prohibition portion 512 is prohibited.

[0067] 19, for example, the placement portion 111 is recessed with respect to the prohibition portion 512. In this configuration, it becomes easier to place the article 300 or the shopping basket 302 on the placement portion 111. Furthermore, the placement portion 111 and the prohibition portion 512 may be on the same plane. In this configuration, it is desirable to provide a mark on the upper surface of the upper portion 510 so that the placement portion 111 and the prohibition portion 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. 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 a 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 placement part 111 is recessed with respect 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 the lower end thereof 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 in such a way 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 in such a way 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 at 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 where 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 on 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 in the range of the diagonal dashed line slanting upward to the right operates. On the front side, the gap between the outer edge 1111 of the placement section 111 and the outer edge 5122 of the prohibited section 512 is larger than that on the back 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 transmitting / receiving section 201 causes the antenna 131 to emit radio waves toward the front side, the intensity of which is such that 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 wave radiated from the antenna 131 is attenuated when it reaches the forbidden portion 512. Then, when this radio wave reaches the upper end of the radio wave absorbing wall 520, it is further attenuated. This radio wave is diffracted at the upper end of the radio wave absorbing wall 520 to generate a diffracted wave. The intensity of the diffracted wave is even smaller than the intensity of the radio wave that reaches the upper end of the radio wave absorbing wall 520. The transmitting / receiving unit 201 causes the antenna 131 to radiate, toward the rear side, a radio wave of such intensity that the RF tag 301 does not operate due to the diffracted wave. In the RF tag reading device 5, because there is a gap between the outer edge 1111 of the mounting portion 111 and the outer edge 5122 of the forbidden portion 512, and because there is the radio wave absorbing wall 520, the intensity of the radio wave radiated by the antenna 131 and reaching the mounting portion 111 is equal to or greater than a predetermined intensity, and the radio wave radiated by the antenna 131 and reaching the periphery of the upper portion 510 is of such intensity that the RF tag 301 does not operate.

[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 placement unit 111 is strong. Therefore, the RF tag 301 attached to the article 300 placed on the upper surface of the placement unit 111 operates, and the information of the RF tag 301 attached to the article 300 placed on the upper surface of the placement unit 111 can be obtained. There is a low possibility that the transmitting / receiving unit 201 will miss reading the information from the RF tag 301 placed on the upper surface of the placement unit 111.

[0076] On the other hand, the strength of the radio waves radiated from the antenna 131 toward the prohibited portion 512 is low. If the RF tag 301 is placed on the upper surface of the prohibited portion 512, there is a risk that the RF tag 301 will not function if the longitudinal direction of the antenna of the RF tag 301 is nearly perpendicular to the main surface of the antenna 131 or if multiple RF tags 301 are overlapped. That is, there is a possibility that the transceiver unit 201 will not read information from the RF tag 301. However, the RF tag 301 is not placed on the upper surface of the prohibited portion 512. The radio waves radiated by the antenna 131 and reaching the periphery of the upper portion 510 have an intensity that does not activate the RF tag 301, so the transceiver unit 201 can exclude the RF tags 301 around the upper portion 510 from the targets for reading information.

[0077] Furthermore, a store usually has a ceiling. When the RF tag reader 5 is used in a store, the radio waves emitted from the antenna 131 may be reflected by the ceiling and reach the RF tags 301 around the upper part 510 (i.e., the 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 by the ceiling are further attenuated before they reach the RF tags 301 around the upper part 510. The transmitting / receiving unit 201 causes the antenna 131 to emit radio waves of an intensity that causes the RF tags 301 around the upper part 510 to not operate 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 obtain information about the RF tags 301 around the upper portion 510. Therefore, the RF tag reader 5 is less likely to fail to read information from the RF tags 301 placed on the upper surface of the placement unit 111, and can prevent erroneous reading of information from the RF tags 301 around the upper portion 510.

[0079] If there is no forbidden portion 512 between the mounting portion 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 portion 111, the radio wave absorbing wall 520 must have a height at which the radio wave radiated from the antenna 131 is attenuated to an intensity at which the RF tag 301 does not operate due to diffracted waves generated at the upper end of the radio wave absorbing wall 520. On the other hand, in the RF tag reading device 5, there is a gap between the outer edge 1111 of the mounting portion 111 and the inner surface 5201 of the radio wave absorbing wall 520. The radio wave radiated from the antenna 131 is attenuated when it reaches the forbidden portion 512. Then, when this radio wave reaches the upper end of the radio wave absorbing wall 520, it is further attenuated. Therefore, the height of the radio wave absorbing wall 520 can be lowered according to the gap between the outer edge 1111 of the mounting portion 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 reader 500A and a controller 200 (not shown). The reader 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 placement 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 side, and a flat plate on the right side. The flat plate on the left side, the flat plate on the back side, and the flat plate on the right side are each vertically erected from the bottom, and are arranged in contact with a 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 reading device 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 reading device 5A is the same as that of the RF tag reading device 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 has a reader 500B and a controller 200 (not shown). The reader 500B has 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 has a mounting portion 111 and a prohibition portion 512B. The radio wave absorbing wall 520B is the same as the radio wave absorbing wall 520 included in the RF tag reader 5 in that it is composed of an arc portion and two protruding portions, and that its upper end is higher than the upper surface of the upper portion 510B. However, the shape of the cross section of the arc portion in 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 is different from the shape 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 that 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 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 larger than that of the RF tag reader 4 according to the fourth embodiment. In the RF tag reader 6, the RF tag 301 around the upper portion 510 may operate and transmit a response radio wave. However, because there is a gap between the outer edge 1111 of the placement portion 111 and the outer edge 5122 of the prohibited portion 512, and because there is a radio wave absorbing wall 520, a difference occurs between the strength of the radio wave radiated by the antenna 131 to reach the placement portion 111 and the strength of the radio wave radiated by the antenna 131 to reach 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 placement portion 111 or around the upper portion 510, as described below.

[0084] The distance between the outer edge 1111 of the placement portion 111 and the outer edge 5122 of the prohibited portion 512 is larger on the front side than on the rear 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 discriminate that the RF tag 301 is around the upper portion 510 when the radio waves reach the outer edge 5122 of the prohibited portion 512. That is, the transceiver unit 210 causes the antenna 131 to radiate radio waves toward the front side at an intensity at which the discrimination unit 212 can discriminate that the RF tag 301 is around the upper portion 510 when the radio waves reach the outer edge 5122 of the prohibited portion 512. Moreover, the RF tag 301 is not present on the prohibited portion 512. There is a large difference between the intensity of the radio waves above the placement portion 111 and the intensity of the radio waves leaking around the upper portion 510. The intensity of the radio waves above the placement portion 111 is much greater than the intensity of the radio waves leaking around the upper portion 510. The discrimination unit 212 can easily discriminate whether the RF tag 301 is on the placement unit 111 or around the upper portion 510 .

[0085] On the other hand, on the back side, the radio wave radiated from the antenna 131 is attenuated when it reaches the forbidden portion 512. Then, when this radio wave reaches the upper end of the radio wave absorbing wall 520, it is further attenuated. This radio wave is diffracted at the upper end of the radio wave absorbing wall 520 to generate a diffracted wave. The intensity of the diffracted wave is even smaller than the intensity of the radio wave that reaches 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 placement unit 111 or around the upper portion 510. In the RF tag reading device 6, because there is a gap between the outer edge 1111 of the placement unit 111 and the outer edge 5122 of the forbidden portion 512, and because there is the radio wave absorbing wall 520, the intensity of the radio wave radiated by the antenna 131 and reaching the placement unit 111 is equal to or greater than a predetermined intensity, and the intensity of the radio wave radiated by the antenna 131 and reaching the periphery of the upper portion 510 is such that the discrimination unit 212 discriminates that the RF tag 301 is around the upper portion 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 placement unit 111 is strong. Therefore, the RF tag 301 attached to the article 300 placed on the upper surface of the placement unit 111 operates, and the information of the RF tag 301 attached to the article 300 placed on the upper surface of the placement unit 111 can be obtained. There is a low possibility that the transmitting / receiving unit 211 will miss reading the information from the RF tag 301 placed on the upper surface of the placement unit 111.

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

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

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

[0090] The diffracted wave generated at the upper end of the radio wave absorbing wall 520 must be attenuated to an intensity at which the discrimination unit 212 can discriminate that an RF tag 301 that has received the diffracted wave and actuated 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 rear side. The radio wave radiated from the antenna 131 is attenuated when it reaches the prohibited portion 512. Then, this radio wave is further attenuated when it reaches 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 according to 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 reader 600 and a controller 200 (not shown). The reader 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 placement 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 is composed of only an arc portion and does not have two protruding portions. 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 the configuration 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, the diffracted waves may cause the RF tags 301 around the upper portion 610 to operate. 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 portion 510 do not operate.

[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 the above, and each RF tag reader and RF tag may communicate using radio waves of other frequencies.

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

[0096] FIG. 26 shows an example of the configuration of a duplicated RF tag 700 including duplicated RF tags 711 and 715. FIG. 26(A) is a plan view of the duplicated RF tag 700. FIG. 26(B) is a front view of the duplicated RF tag 700. The duplicated RF tag 700 has an RF tag 711 and an RF tag 715. The RF tag 711 and the RF tag 715 are passive RF tags. The main surface of the RF tag 711 and the main surface of the RF tag 715 are on the same plane. As can be seen from FIG. 26(B), the duplicated RF tag 700 is thin. The duplicated RF tag 700 is, for example, a combination of the RF tag 711 and the RF tag 715 sandwiched between thin, hard paper (e.g., cardboard, etc.) from the front and back sides. These thin, hard papers are permeable to radio waves. The RF tag 711 and the RF tag 715 do not overlap, and 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 of, for example, a frequency of 860 to 960 MHz. When the antenna 712 receives radio waves radiated by an antenna of the RFID reader / writer or the like, electric power is generated. The IC chip 713 operates using the electric 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 radiated by the antenna of the RFID reader / writer or the like. The response radio wave includes information including the tag ID.

[0098] The RF tag 715 has an antenna 716 and an IC chip 717. The IC chip 717 operates using power generated by radio waves received by the antenna 716. The RF tag 715 operates in the same manner as the RF tag 711. The IC chip 713 and the 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. The information stored in the IC chip 713 and the information stored in the IC chip 717 may also 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 a response radio wave. 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 a response radio wave. However, even if antenna 716 cannot receive radio waves, antenna 712 can receive radio waves, and RF tag 711 can transmit a response radio wave.

[0100] Fig. 27 shows an example in which a duplicated RF tag 700 is placed on the placement section 111 of the RF tag reader 1 in Fig. 1. 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 example 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 surface of the antenna 722 and the main surface of the antenna 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, for example, a combination of the antennas 722 and 726, and the IC chip 723 sandwiched between thin and hard paper (e.g., cardboard, etc.) from the front and back sides. These thin and hard papers are permeable to radio waves. The IC chip 723 is attached to the center of the antenna 722. The IC chip 723 stores information including the tag ID.

[0102] The antennas 722 and 726 do not overlap, and are arranged so that their longitudinal directions are perpendicular to each other. The antennas 722 and 726 are arranged, for example, in an L shape. The center of the antenna 726 is connected to the IC chip 723 by a predetermined wiring 728. The duplicated 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 radiated by an antenna such as an RFID reader / writer, electric power is generated. For example, when antenna 726 receives radio waves radiated by an antenna such as an RFID reader / writer, electric power is generated. A part of the electric power is supplied to IC chip 723 via wiring 728. IC chip 723 operates using the electric power. Information stored in IC chip 723 is transmitted to antenna 726 via wiring 728. Antenna 726 transmits a response radio wave including the information. That is, antenna 722 and antenna 726 transmit a response radio wave including the information stored in IC chip 723.

[0104] 26 shows an example in which the RF tags 711 and 715 are arranged in an L-shape so as not to overlap, but the L-shape is not the only possibility as long as the RF tags 711 and 715 do not overlap and their longitudinal directions are perpendicular to each other. Similarly, in 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, but the L-shape is not the only possibility as long as the antennas 722 and 726 do not overlap and their longitudinal directions are perpendicular to each other.

[0105] In the above-described embodiment, an example of a dual RF tag in which the RF tags 711 and 715 are sandwiched between thin, hard paper (e.g., cardboard) from the front and back sides has been shown, but the present invention is not limited to this, and may 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 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 disclosed herein 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 duplicated RF tag of the present disclosure can also be used for purposes other than the above-mentioned RF tag reader. For example, it can be used in a location information acquisition system in a building having multiple rooms, in which an RFID reader / writer antenna is installed on the ceiling or the like of each room. When each person in the building wears the duplicated 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 around 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 placement section 111. Also, 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 placement section 111.

[0109] Although the embodiments of the present invention have been described above, various modifications and combinations required due to convenience in design or manufacturing or other factors are included in 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 section, 110... upper section, 111... placement section, 1111... outer edge of placement section 111, 112, 112A, 112B, 112C... prohibited section, 1121... inner edge of prohibited section 112, 1122... outer edge of prohibited section 112, 1121A... inner edge of prohibited section 112A, 1122A... outer edge of prohibited section 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 section, 510, 510A, 510B...upper portion, 512, 512A, 512B...prohibited portion, 5121...inner edge of prohibited portion 512, 5122...prohibited portion 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 section of comparative example, 612... prohibited 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, which is made of a material that transmits radio waves and has a placement section on which an article having a passive RF tag attached thereto is placed, and which is made of a material that transmits radio waves and surrounds the placement section, and has a prohibition section on which it is prohibited to place an RF tag, with a gap between the outer edge of the placement section and the outer edge of the prohibition section; an antenna for communicating with the RF tag, the antenna being located below the placement portion, at a position where radio waves radiated from the antenna propagate while spreading upward to reach the placement portion and the prohibition portion, the antenna being located at such a position that the antenna radiates radio waves with a high intensity toward the placement portion and radiates radio waves with a lower intensity than the radio waves 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 upper surface of the placement section and to prevent erroneous reading of information from RF tags around the upper portion. RF tag reader.

2. The RF tag reading device of claim 1, wherein a gap is provided between the outer edge of the placement portion and the outer edge of the prohibition portion, so that the strength of the radio waves radiated by the antenna and reaching the placement portion can be made to be equal to or greater than a predetermined strength, and the strength of the radio waves radiated by the antenna and reaching the periphery of the upper portion can be made to be such that the RF tag does not operate.

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

4. The placement portion is circular, a polarization method of the radio wave radiated by the antenna is a circular polarization method, and a center of a radiation area of ​​the antenna that radiates the radio wave is located directly below the center of the mounting portion; 2. 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; Due to the provision 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, it is possible to reduce the possibility of failing to read information from an RF tag attached to an article placed on the upper surface of the placement section, and to prevent erroneous reading of information from RF tags around the upper portion.

2. The RF tag reader according to claim 1.

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

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

8. The placement portion is circular, a polarization method of the radio wave radiated by the antenna is a circular polarization method, and a center of a radiation area of ​​the antenna that radiates the radio wave is located directly below the center of the mounting portion; 6. The RF tag reader according to claim 5.

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