RF tag reader

Abstract

To install an antenna for communicating with an RF tag 301 on the side surface of a storage part 100, in an RF tag reader 1 which has an opening 110 in the upper part of the storage part 100, and reads out information from the RF tag 301 which is in the inside of the storage part 100 in a state where the opening 110 is opened.SOLUTION: A bottom surface part 120, a front surface part 121 and a rear surface part 123 include radio wave shield layers. A right side surface part 124 includes a radio wave absorbing layer. A side surface antenna is installed on the inner surface of a lower part 1221 of a left side surface part 122. The upper end of the rear surface part 123 and the upper end of the right side surface part 124 are higher than the upper edge of the side surface antenna. Another end of the right side surface part 124 overhangs closer to a front surface side by a predetermined length than the front surface part 121. Thereby, the strength of a radio wave which is radiated from the side surface antenna and leaks to the outside of the storage part 100 from the opening 110 decreases, and information on the RF tag 301 which is in the inside of the storage part 100 can be acquired.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] Patent Document 1 describes a stationary reader that reads information from an RF tag attached to an article. This reader includes an antenna and a shield. The antenna is housed inside the shield and emits radio waves for communicating with the RF tag. The shield surrounds the article and has an opening facing upward that is wider than the article. The reader reads information from the RF tag with the shield open and facing upward. In the reading device described in Patent Document 1, the radio waves emitted from the antenna are emitted only upwards outside the reading device. The shielding section prevents the radio waves from spreading around the reading device, thereby reducing the impact of the radio waves on other devices. The shielding section also prevents radio waves from other devices around the reading device from entering the inside of the reading device, thereby reducing the deterioration of reading accuracy caused by radio wave interference.

[0003] However, radio waves have the properties of reflection and diffraction. In the reader described in Patent Document 1, the communication range between the antenna and the RF tag extends to the periphery of the reader due to the reflection of radio waves from the ceiling and the diffraction of radio waves from the periphery of the opening. For this reason, there is a risk that the reader may erroneously read the information on RF tags in the vicinity. In addition, the strength of the radio waves received by an RF tag weakens depending on the orientation of the RF tag relative to the antenna. Furthermore, when there are multiple RF tags inside a shield, the strength of the radio waves received by the RF tags weakens depending on their relative positions.

[0004] Therefore, in the reader described in Patent Document 1, if the radio waves radiated from the antenna are strengthened, the RF tags outside the shield may be activated by radio waves reflected from the ceiling or diffracted around the edge of the opening, and information may be read from the RF tags outside the shield. On the other hand, if the radio waves radiated from the antenna are weakened, information may not be read from the RF tags inside the shield.

[0005] In consideration of these points, the inventors of the present invention obtained a patent for the invention described in Patent Document 2. The RF tag reader described in Patent Document 2, like the reader described in Patent Document 1, has an opening at the top of the storage section (corresponding to the shield section in the reader described in Patent Document 1). A bottom antenna is provided at the bottom of the storage section, and a side antenna is provided on a side panel on the front side of the storage section. The bottom antenna and side antenna each radiate radio waves for communicating with the RF tag. The inside of the storage section (side and bottom) is covered with a radio wave absorbing layer. The side panels, except for the side panel on the front side, are at a height such that the intensity of the radio waves radiated from the side antenna and leaking from the opening to the rear side outside the storage section is sufficiently small. The top edge of the front side panel of this RF tag reader is lower than the top edges of the other side panels, making it easy to insert and remove items and shopping baskets from the front side.

[0006] In the RF tag reader described in Patent Document 2, the radio waves radiated from the bottom antenna and reflected by the ceiling or diffracted by the periphery of the opening are attenuated by the time they reach the RF tags around the RF tag reader. Also, the radio waves radiated from the side antenna and leaking from the opening to the rear side outside the storage unit are weak. This RF tag reading device determines that the RF tag is outside the storage section, for example, when the RSSI (Received Signal Strength Indicator) obtained from the response radio waves transmitted from the RF tag that received radio waves radiated from a bottom antenna installed on the bottom surface or the strength of the response radio waves is small, and the RSSI obtained from the response radio waves transmitted from the RF tag that received radio waves radiated from a side antenna installed on the front side or the strength of the response radio waves is small. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2018-190255 A [Patent Document 2] Patent No. 7280583 Summary of the Invention [Problem to be solved by the invention]

[0008] The upper end of the side panel on the front side of the storage unit in the RF tag reader described in Patent Document 2 is lower than the upper ends of the other side panels. Therefore, if antennas for communicating with RF tags are installed on the right and left sides of the storage unit in this RF tag reader, strong radio waves may leak beyond the opening on the front side panel to the outside of the storage unit, causing information to be erroneously read from an RF tag outside the storage unit. For this reason, antennas cannot be installed on the right and left sides of the storage unit in this RF tag reader.

[0009] The object of the present invention is to provide an RF tag reading device that has an opening at the top of a storage section and reads information from a passive RF tag inside the storage section when the opening is open, and in which an antenna for communicating with the RF tag can be installed on the side of the storage section. [Means for solving the problem]

[0010] In order to achieve the above object, the RF tag reader of the present invention comprises: An RF tag reader that has a storage unit with an opening at the top through which an article having a passive RF tag attached can be inserted and removed, and that reads information from an RF tag attached to an article stored inside the storage unit with the opening open, The storage section is A bottom surface portion including an electromagnetic wave absorbing layer and / or an electromagnetic wave reflecting layer; a front portion including an electromagnetic wave absorbing layer and / or an electromagnetic wave reflecting layer; a rear portion facing the front portion, the rear portion including a radio wave absorbing layer and / or a radio wave reflecting layer, no antenna being provided, and the upper end of the rear portion being higher than the upper end of the front portion and the upper edge of the side antenna; a side antenna for emitting radio waves for communicating with the RF tag and receiving response radio waves transmitted from the RF tag; a first side portion having one end and the other end fixed to one end of the front portion and one end of the rear portion, respectively, the first side portion having the side antenna installed on an inner surface thereof; a second side portion facing the first side portion, one end of which is fixed to the other end of the back portion and the other end of which projects forward beyond the front portion by a predetermined length, and the other end of the front portion is fixed between the one end and the other end, the second side portion including a radio wave absorbing layer, no antenna being installed, and the upper end of the second side portion being higher than the upper end of the front portion and the upper edge of the side antenna; Equipped with Because the upper end of the rear portion and the upper end of the second side portion are higher than the upper edge of the side antenna, and the other end of the second side portion extends a predetermined length toward the front side beyond the front portion, the strength of the radio waves radiated from the side antenna and leaking out of the storage portion through the opening is reduced, making it possible to obtain information about the RF tag inside the storage portion.

[0011] Preferably, the RF tag reader of the present invention comprises: A bottom antenna is provided on the top surface of the bottom portion to emit radio waves for communicating with the RF tag and to receive response radio waves transmitted from the RF tag; The first side portion includes an electromagnetic wave absorbing layer and / or an electromagnetic wave reflecting layer.

[0012] Preferably, the RF tag reader of the present invention comprises: a first storage limiting portion located between the first side portion and the second side portion, the first storage limiting portion dividing the interior of the storage portion into a space between the first side portion and the first storage limiting portion through which radio waves radiated from the side antenna propagate while spreading up, down, left, and right, and a space between the first storage limiting portion and the second side portion which is a storage space capable of storing the item; a second accommodation limiting section located above the bottom section, the second accommodation limiting section dividing the interior of the accommodation section into a space between the bottom section and the second accommodation limiting section, through which radio waves radiated from the bottom antenna propagate while spreading, and a space above the second accommodation limiting section, which is the accommodation space; Equipped with.

[0013] In addition, the RF tag reader of the present invention comprises: An RF tag reader that has a storage unit with an opening at the top through which an article having a passive RF tag attached can be inserted and removed, and that reads information from an RF tag attached to an article stored inside the storage unit with the opening open, A bottom surface portion including an electromagnetic wave absorbing layer and / or an electromagnetic wave reflecting layer; a front antenna for emitting radio waves for communicating with the RF tag and receiving response radio waves transmitted from the RF tag; A front part including an electromagnetic wave absorbing layer and / or an electromagnetic wave reflecting layer, the front antenna being disposed on an inner surface thereof; a rear portion facing the front portion, the rear portion including an electromagnetic wave absorbing layer, no antenna being provided, and the rear portion having an upper end higher than an upper end of the front portion and an upper edge of the front antenna; a third storage limiting section located between the front section and the rear section, the third storage limiting section dividing the interior of the storage section into a space between the front section and the third storage limiting section through which radio waves radiated from the front antenna propagate while spreading up, down, left, and right, and a space between the third storage limiting section and the rear section which is a storage space capable of storing the item; a side antenna for emitting radio waves for communicating with the RF tag and receiving response radio waves transmitted from the RF tag; a first side portion having one end and the other end fixed to one end of the front portion and one end of the rear portion, respectively, the first side portion including a radio wave absorbing layer and / or a radio wave reflecting layer, and the side antenna being installed on an inner surface of the first side portion; a second side portion facing the first side portion, one end of which is fixed to the other end of the back portion and the other end of which projects forward beyond the front portion by a predetermined length, and the other end of the front portion is fixed between the one end and the other end, the second side portion including a radio wave absorbing layer, no antenna being installed, and the upper end of the second side portion being higher than the upper end of the front portion and the upper edge of the side antenna; Equipped with Since the upper end of the rear portion, the upper end of the first side portion, and the upper end of the second side portion are higher than the upper edge of the front antenna, the strength of the radio waves radiated from the front antenna and leaking to the outside of the storage portion through the opening is reduced, making it possible to obtain information about the RF tag inside the storage portion, The upper end of the rear portion and the upper end of the second side portion are higher than the upper edge of the side antenna, the other end of the second side portion protrudes a predetermined length toward the front side beyond the front portion, and the radio waves radiated from the side antenna are attenuated while propagating through the space between the front portion and the third storage limiting portion, thereby reducing the intensity of the radio waves radiated from the side antenna and leaking outside the storage portion through the opening, making it possible to obtain information about the RF tag inside the storage portion.

[0014] In addition, the RF tag reader of the present invention comprises: An RF tag reader that has a storage unit with an opening at the top through which an article having a passive RF tag attached can be inserted and removed, and that reads information from an RF tag attached to an article stored inside the storage unit with the opening open, A bottom surface portion including an electromagnetic wave absorbing layer and / or an electromagnetic wave reflecting layer; a front antenna for emitting radio waves for communicating with the RF tag and receiving response radio waves transmitted from the RF tag; A front part including an electromagnetic wave absorbing layer and / or an electromagnetic wave reflecting layer, the front antenna being disposed on an inner surface thereof; a rear portion facing the front portion, the rear portion including an electromagnetic wave absorbing layer, no antenna being provided, and the rear portion having an upper end higher than an upper end of the front portion and an upper edge of the front antenna; a third storage limiting section located between the front section and the rear section, the third storage limiting section dividing the interior of the storage section into a space between the front section and the third storage limiting section through which radio waves radiated from the front antenna propagate while spreading up, down, left, and right, and a space between the third storage limiting section and the rear section which is a storage space capable of storing the item; a side antenna for emitting radio waves for communicating with the RF tag and receiving response radio waves transmitted from the RF tag; a first side portion having one end and the other end fixed to one end of the front portion and one end of the rear portion, respectively, the first side portion including a radio wave absorbing layer and / or a radio wave reflecting layer, and the side antenna being installed on an inner surface of the first side portion; a second side portion facing the first side portion, one end of which is fixed to the other end of the rear portion and the other end of the front portion, the second side portion including an electromagnetic wave absorbing layer, no antenna being provided, and the upper end of the second side portion being higher than the upper end of the front portion and an upper edge of the side antenna; Equipped with Since the upper end of the rear portion, the upper end of the first side portion, and the upper end of the second side portion are higher than the upper edge of the front antenna, the strength of the radio waves radiated from the front antenna and leaking to the outside of the storage portion through the opening is reduced, making it possible to obtain information about the RF tag inside the storage portion, Because the upper end of the rear portion and the upper end of the second side portion are higher than the upper edge of the side antenna, and because the radio waves radiated from the side antenna are attenuated as they propagate through the space between the front portion and the third storage limiting portion, the strength of the radio waves radiated from the side antenna and leaking out of the storage portion through the opening is reduced, making it possible to obtain information about the RF tag inside the storage portion.

[0015] Preferably, the RF tag reader of the present invention comprises: The antenna includes a first accommodation limiting portion located between the first side portion and the second side portion, the first accommodation limiting portion dividing the interior of the accommodation portion into a space between the first side portion and the first accommodation limiting portion through which radio waves radiated from the side antenna propagate while spreading up, down, left, and right, and a space between the first accommodation limiting portion and the second side portion which is the accommodation space.

[0016] Preferably, the RF tag reader of the present invention comprises: The opening allows a shopping basket containing the item to be inserted and removed, The storage space is capable of storing a part or the whole of the shopping basket. Effect of the Invention

[0017] According to the present invention, in an RF tag reading device that has an opening at the top of a storage section and reads information from a passive RF tag inside the storage section when the opening is open, an antenna for communicating with the RF tag can be installed on the side of the storage section. [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] 2 is a cross-sectional view taken along line AA in FIG. 1. [Diagram 3] FIG. 2 is a cross-sectional view taken along line BB in FIG. [Figure 4] 2 is a top view of an example of a storage unit in the RF tag reader of FIG. 1. [Diagram 5] FIG. 2 is a rear view of the RF tag reader of FIG. 1. [Figure 6] FIG. 2 is a view of the RF tag reader in FIG. 1 as seen from the right side. [Figure 7] 2 is a diagram showing an example of radio waves radiated from a side antenna in the RF tag reader of FIG. 1. [Figure 8] 2 is a diagram showing an example of radio waves radiated from a side antenna and reaching a right side portion of the RF tag reader of FIG. 1, as viewed from the right side of the RF tag reader. [Figure 9] 1. FIG. 4 is a diagram showing a comparative example of the RF tag reader of FIG. 1, in which the right side portion includes a radio wave reflective layer. [Figure 10] 10 is a vertical cross-sectional view of an example of an RF tag reader according to a second embodiment of the present invention, which corresponds to a cross-sectional view taken along line BB in FIG. [Figure 11] FIG. 11 is a perspective view of an example of an RF tag reader according to a third embodiment of the present invention. [Figure 12] 12 is a cross-sectional view taken along line CC in FIG. 11. [Figure 13] FIG. 12 is a cross-sectional view taken along line DD in FIG. [Figure 14] 12 is a top view of an example of a storage unit in the RF tag reader of FIG. 11. [Figure 15] 12 is a rear view of the RF tag reader of FIG. 11. FIG. [Figure 16] 12 is a diagram showing an example of radio waves radiated from the front antenna in the RF tag reading device of FIG. 11. [Figure 17] 12 is a diagram showing an example of radio waves radiated from a side antenna in the RF tag reader of FIG. 11. FIG. [Figure 18]12 is a diagram showing an example of radio waves radiated from a side antenna and reaching a right side portion of the RF tag reader of FIG. 11, as viewed from the right side of the RF tag reader. [Figure 19] 13A and 13B are diagrams for explaining an example of an effect achieved by the RF tag reading device according to the third embodiment. [Figure 20] FIG. 12 is a diagram showing a comparative example of the RF tag reader of FIG. 11, in which the rear surface portion includes a radio wave reflective layer. [Figure 21] 21 is a vertical cross-sectional view of an example of an RF tag reader according to a fourth embodiment of the present invention, which corresponds to a cross-sectional view taken along line CC in FIG. [Figure 22] FIG. 13 is a perspective view of an example of an RF tag reader according to a fifth embodiment of the present invention. [Figure 23] 23 is a cross-sectional view taken along line EE in FIG. 22. [Figure 24] 23 is a cross-sectional view taken along the line FF in FIG. 22. [Diagram 25] 23 is a top view of an example of a storage section in the RF tag reader of FIG. 22. [Figure 26] 23 is a diagram showing an example of radio waves radiated from a side antenna and reaching a right side portion of the RF tag reader of FIG. 22, as viewed from the right side of the RF tag reader. FIG. [Figure 27] 27 is a vertical sectional view of an example of an RF tag reader according to a sixth embodiment of the present invention, which corresponds to a sectional view taken along line EE in FIG. 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] (First embodiment) 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 cross-sectional view taken along line AA in Fig. 1. Fig. 3 is a cross-sectional view taken along line BB in Fig. 1. Fig. 4 is a top view of an example of a storage section 100 in the RF tag reader 1 of Fig. 1. The RF tag reader 1 has a storage unit 100 and a control unit 200. The storage unit 100 has an opening 110 at its top.

[0021] An opening 110 of the storage unit 100 of the RF tag reader 1 allows an article 300 with an RF tag 301 attached to be put in and taken out. The storage space inside the storage unit 100 is capable of storing the article 300. The storage space will be described later.

[0022] The opening 110 allows the insertion and removal of a shopping basket 400 containing the article 300 therein. The storage space inside the storage unit 100 is capable of storing a part or the whole of the shopping basket 400. For example, when the RF tag reader 1 is incorporated into a self-checkout register and used in a store, items 300 with RF tags 301 attached are displayed on shelves or tables in the store. A customer selects an item 300 that he or she likes and places it in a shopping basket 400. The customer then places a part or all of the shopping basket 400 into the storage space through the opening 110.

[0023] The article 300 is, for example, a book, an article of clothing, a food product, or the like. The article may be packed in a box. The article 300 is preferably an object that easily transmits radio waves. For example, the article 300 is preferably an object that does not contain metal or moisture. The RF tag 301 is used, for example, for centralized management of multiple items 300 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, self-checkouts in stores, etc.

[0024] The RF tag 301 stores, for example, a unique tag ID (IDentifier) ​​that is determined so as to uniquely identify the article 300. When the article 300 to which the RF tag 301 is attached is stored inside the storage unit 100, the RF tag reader 1 reads information including the tag ID from the RF tag 301. The RF tag 301 is a well-known passive RF tag. The RF tag reader 1 communicates with the RF tag 301 using, for example, radio waves in the UHF band with a frequency of 860 to 960 MHz.

[0025] As shown in Figures 1 to 4, the storage section 100 has a bottom section 120, a front section 121, a left side section 122, a rear section 123, a right side section 124, a mounting plate 150, a side storage limiting plate 151, a bottom antenna 160, and a side antenna 161. The bottom surface portion 120 constitutes the bottom of the housing portion 100. The bottom surface portion 120 is, for example, rectangular. The bottom surface portion 120 includes a flat plate 130 and a radio wave shielding layer 140. The radio wave shielding layer 140 covers, for example, the upper surface of the flat plate 130. Here, the radio wave shielding layer is a radio wave absorbing layer or a radio wave reflecting layer. The radio wave shielding layer may include both a radio wave absorbing layer and a radio wave reflecting layer. The radio wave absorbing layer absorbs radio waves. The radio wave absorbing layer is made of, for example, a radio wave absorbing sheet. The radio wave absorbing sheet is a sheet made of a material in which magnetic metal powder is mixed into a rubber material. Moreover, the radio wave reflecting layer reflects radio waves. The radio wave reflecting layer is made of, for example, a metal.

[0026] The sides of the storage section 100 are made up of a front section 121, a left side section 122, a rear section 123, and a right side section . The front portion 121 is, for example, rectangular. The front portion 121 stands perpendicularly to the bottom portion 120 from the front edge of the bottom portion 120. The front portion 121 includes a flat plate 131 and a radio wave shielding layer 141. The radio wave shielding layer 141 covers, for example, the inner surface of the flat plate 131. The upper end of the front portion 121 is lower than the upper end of the left side portion 122, the upper end of the back portion 123, and the upper end of the right side portion 124.

[0027] One end and the other end of the left side surface portion 122 are fixed to one end of the front surface portion 121 and one end of the rear surface portion 123, respectively. The left side surface portion 122 is composed of a lower portion 1221 and a middle portion 1222. The lower portion 1221 stands perpendicular to the left edge of the bottom surface portion 120. The middle portion 1222 extends from the upper end of the lower portion 1221 in the direction of the right side surface portion 124, parallel to the bottom surface portion 120. The lower portion 1221 and the middle portion 1222 respectively include a flat plate 1321 and a flat plate 1322. A radio wave shielding layer 142 covers, for example, the inner surfaces of the flat plates 1321 and 1322.

[0028] The rear portion 123 faces the front portion 121. The rear portion 123 stands perpendicularly to the bottom portion 120 from the edge of the rear side of the bottom portion 120. As shown in FIG. 5, the rear portion 123 is composed of a portion closer to the other end and a lower portion closer to one end. The lower portion closer to one end has a shape that matches the shape of the other end of the left side portion 122 (i.e., the rear side of the left side portion 122). The portion closer to the other end gradually becomes higher from the end of the middle portion 1222 of the left side portion 122 toward the upper end of the right side portion 124. The upper end of the other end side of the rear portion 123 is at the same height as the upper end of the right side portion 124. The other end of the rear portion 123 is fixed to one end of the right side portion 124. The upper end of the rear portion 123 is higher than the upper end of the front portion 121. Here, the upper end of the rear portion 123 refers to the portion closer to the other end excluding the portion closer to one end of the rear portion 123 that is lower. The back surface portion 123 includes a flat plate 133 and a radio wave shielding layer 143. The radio wave shielding layer 143 covers the inner surface of the flat plate 133, for example.

[0029] The right side surface portion 124 faces the left side surface portion 122. Fig. 6 shows an example of the shape of the right side surface portion 124 when the RF tag reader 1 is viewed from the right side. One end of the right side surface portion 124 is fixed to the other end of the back surface portion 123. The other end of the right side surface portion 124 protrudes a predetermined length toward the front side from the front surface portion 121, and the other end of the front surface portion 121 is fixed between the one end and the other end of the right side surface portion 124. As shown in Figs. 4 and 6, the right side surface portion 124 has a portion that stands vertically from the right edge of the bottom surface portion 120 relative to the bottom surface portion 120, and a portion that protrudes a predetermined length toward the front side from the front surface portion 121. The right side surface portion 124 includes a flat plate 134 and an electromagnetic wave absorbing layer 144. The electromagnetic wave absorbing layer 144 covers the inner surface of the flat plate 134, for example. The upper end of right side surface portion 124 has a constant height from one end to the other end, and this height is the same as the height of the upper end of the other end side of rear surface portion 123. Therefore, the upper end of right side surface portion 124 is higher than the upper end of front surface portion 121.

[0030] The lower end of the front portion 121 , the lower end of the left side portion 122 , the lower end of the back portion 123 , and the lower end of the right side portion 124 are fixed to the respective edges of the bottom portion 120 . The storage section 100, which opens upward, is formed by the bottom section 120, the front section 121, the left side section 122, the back section 123, and the right side section 124. This opening is the opening 110 described above.

[0031] The radio wave shielding layer 141 included in the front part 121 may cover the outer surface of the flat plate 131 instead of the inner surface of the flat plate 131, or may be sandwiched between the two flat plates. The same applies to the left side part 122 and the back part 123. The radio wave absorbing layer 144 included in the right side surface portion 124 may cover the outer surface of the flat plate 134 instead of covering the inner surface of the flat plate 134, or may be sandwiched between two flat plates. In this case, however, the flat plate on the inner surface side of the radio wave absorbing layer 144 must be made of a material that transmits radio waves. The radio wave shielding layer 140 included in the bottom surface portion 120 may also cover the lower surface of the flat plate 130 instead of covering the upper surface of the flat plate 130, or may be sandwiched between two flat plates. The left side surface portion 122 is an example of a first side surface portion of the present invention, and the right side surface portion 124 is an example of a second side surface portion of the present invention.

[0032] The bottom antenna 160 is an antenna installed on the upper surface of the bottom part 120. The bottom antenna 160 radiates radio waves upward for communicating with the RF tag 301 and receives response radio waves transmitted from the RF tag 301. The bottom antenna 160 is, for example, a planar antenna or a sheet antenna. The bottom antenna 160 radiates, for example, circularly polarized radio waves, or radiates radio waves while switching between horizontal polarization and vertical polarization. The response radio wave is a radio wave carrying information and transmitted by the RF tag 301 when the RF tag 301 receives a radio wave from the bottom antenna 160. The same applies to the side antenna 161 and the front antenna 162 described later.

[0033] The side antenna 161 is an antenna installed on the inner surface of the lower part 1221 of the left side part 122 (i.e., the inner surface of the left side part 122). The side antenna 161 radiates radio waves for communicating with the RF tag 301 toward the right side part 124, and receives response radio waves transmitted from the RF tag 301. The side antenna 161 is, for example, a planar antenna or a sheet antenna. The side antenna 161 radiates, for example, circularly polarized radio waves, or radiates radio waves while switching between horizontally polarized waves and vertically polarized waves. The upper end of the right side surface part 124 is higher than the upper edge of the side surface antenna 161. Here, the upper edge of the side surface antenna 161 refers to the highest position of the portion of the side surface antenna 161 that radiates radio waves. It should be noted that no antenna for emitting radio waves for communicating with the RF tag 301 is provided on the front portion 121, the back portion 123, or the right side portion .

[0034] The mounting plate 150 is, for example, a rectangular flat plate. The mounting plate 150 is located above the bottom surface portion 120. The mounting plate 150 is fixed parallel to the bottom surface portion 120, for example, to the inner surfaces of the front surface portion 121, the left side surface portion 122, the back surface portion 123, and the right side surface portion 124, with a predetermined distance between the mounting plate 150 and the bottom surface portion 120. The space above the loading plate 150 and surrounded by the front portion 121, the side storage limiting plate 151, the rear portion 123, and the right side portion 124 forms a storage space. The storage space is a space capable of storing part or all of the article 300 and / or the shopping basket 400. The article 300 and the shopping basket 400 are placed on the loading plate 150.

[0035] The side storage limiting plate 151 is, for example, a rectangular flat plate. The side storage limiting plate 151 is vertically erected from the upper surface of the mounting plate 150 between the side antenna 161 and the bottom antenna 160, with a predetermined distance from the left side surface portion 122. The upper end of the side storage limiting plate 151 is fixed, for example, to the right end of the middle portion 1222 in the left side surface portion 122. The height of the side storage limiting plate 151 is the same as the distance between the upper surface of the mounting plate 150 and the right end of the middle portion 1222 in the left side surface portion 122. One end and the other end of the side storage limiting plate 151 are fixed, for example, to the front portion 121 and the rear portion 123, respectively, and the width of the side storage limiting plate 151 is the same as the distance between the front portion 121 and the rear portion 123.

[0036] The mounting plate 150 divides the inside of the accommodation unit 100 into a space between the bottom surface portion 120 and the mounting plate 150, and a space above the mounting plate 150. Here, the space between the bottom surface portion 120 and the mounting plate 150 is a space through which radio waves radiated from the bottom antenna 160 propagate while spreading. The space above the mounting plate 150 is an accommodation space. The side storage limiting plate 151 divides the inside of the storage section 100 into a space between the left side section 122 and the side storage limiting plate 151, and a space between the side storage limiting plate 151 and the right side section 124. Here, the space between the left side section 122 and the side storage limiting plate 151 is a space through which radio waves radiated from the side antenna 161 propagate while spreading up, down, left, and right. The space between the side storage limiting plate 151 and the right side section 124 is a storage space. The side storage limiting plate 151 is an example of a first storage limiting portion of the present invention, and the placement plate 150 is an example of a second storage limiting portion of the present invention.

[0037] The control unit 200 includes a transmission / reception unit 211, an acquisition unit 212, and an I / F (interface) 213. The transmitter / receiver 211 causes the bottom antenna 160 and the side antenna 161 to radiate circularly polarized radio waves, or when linear polarization is used, causes the antenna to radiate radio waves while switching between horizontal and vertical polarization at high speed. Furthermore, when the bottom antenna 160 and the side antenna 161 receive a response radio wave, the transmitting / receiving unit 211 obtains information including the tag ID from the response radio wave. The transmitter / receiver unit 211 may cause the bottom antenna 160 and the side antenna 161 to radiate radio waves at different times, or may cause the bottom antenna 160 and the side antenna 161 to radiate radio waves simultaneously if mutual interference between the radio waves radiated from the bottom antenna 160 and the side antenna 161 can be ignored.

[0038] The RF tag 301 obtains the power necessary to operate by receiving radio waves transmitted from the bottom antenna 160 and / or the side antenna 161. 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.

[0039] In the RF tag reading device 1, the upper end of the back portion 123 and the upper end of the right side portion 124 are higher than the upper edge of the side antenna 161, so that the strength of the radio waves radiated from the side antenna 161 and leaking from the opening 110 to the outside of the accommodating portion 100 beyond the upper end of the back portion 123 and the upper end of the right side portion 124 is reduced to a level that does not activate the RF tag 301 outside the accommodating portion 100. In the RF tag reading device 1, the other end of the right side portion 124 protrudes a predetermined length toward the front side beyond the front portion 121, so that the strength of the radio waves radiated from the side antenna 161 and leaking from the other end of the right side portion 124 to the outside of the accommodating portion 100 (i.e., the strength of the radio waves leaking from the opening 110 to the outside of the accommodating portion 100) is reduced to a level that does not activate the RF tag 301 outside the accommodating portion 100. 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 obtain any information from the RF tag 301 located outside the storage unit 100 . Therefore, the RF tag reader 1 can obtain only the information read from the RF tag 301 inside the storage unit 100 when the side antenna 161 receives a response radio wave from the RF tag 301. That is, the RF tag reader 1 can obtain the information of the RF tag 301 inside the storage unit 100 by reducing the intensity of the radio wave radiated from the side antenna 161 and leaking to the outside of the storage unit 100 through the opening 110. In the first embodiment, the specified length in the present invention is a length that reduces the intensity of radio waves leaking from the other end of the right side portion 124 to the outside of the storage portion 100 to a level that does not activate the RF tag 301 that receives the radio waves.

[0040] Furthermore, the transmitter / receiver 211 causes the bottom antenna 160 to radiate radio waves of an intensity that will not activate the RF tag 301 outside the storage unit 100 due to radio waves reflected from the ceiling and radio waves diffracted around the periphery of the opening 110. This allows the RF tag reader 1 to obtain only the information read from the RF tag 301 inside the storage unit 100 when the bottom antenna 160 receives the response radio waves.

[0041] The acquisition unit 212 identifies each RF tag 301 based on the tag ID included in the information of the RF tag 301 acquired from the response radio waves received by the bottom antenna 160 and the side antenna 161, respectively, and acquires the information for each RF tag 301. The I / F 213 transmits information about each RF tag 301 identified by the acquisition unit 212 to an external device (such as an accounting device) and receives operating instructions for the RF tag reading device 1 from the external device.

[0042] Fig. 7 shows an example of radio waves emitted from the side antenna 161 in the RF tag reader 1 of Fig. 1. The side antenna 161 receives response radio waves transmitted from the RF tag 301 that has received radio waves within the range indicated by the diagonal dashed line sloping upward to the right. Radio waves radiated from side antenna 161 may pass over the upper end of rear portion 123 and the upper end of right side portion 124 and leak from opening 110 to the outside of housing portion 100. However, the upper end of rear portion 123 and the upper end of right side portion 124 are higher than the upper edge of side antenna 161. As a result, the strength of the radio waves that pass over the upper end of rear portion 123 and the upper end of right side portion 124 and leak from opening 110 to the outside of housing portion 100 is lower than the strength of the radio waves inside housing portion 100. The upper end of the rear portion 123 and the upper end of the right side portion 124 are at a height that reduces the strength of radio waves that extend beyond those upper ends and leak through the opening 100 to the outside of the storage portion 100 to a level that does not activate the RF tag 301 outside the storage portion 100.

[0043] Fig. 8 shows an example of radio waves radiated from the side antenna 161 and reaching the right side part 124 in the RF tag reader 1 of Fig. 1, as viewed from the right side of the RF tag reader 1. The RF tag 301 that receives radio waves within the range of the diagonal dashed line sloping upward to the right operates and transmits a response radio wave. The radio waves radiated from the side antenna 161 may leak from the other end of the right side portion 124 to the outside of the storage unit 100 (i.e., leak from the opening 110 to the outside of the storage unit 100). However, the other end of the right side portion 124 protrudes a predetermined length toward the front side beyond the front portion 121. This reduces the strength of the radio waves leaking from the other end of the right side portion 124 to the outside of the storage unit 100 to a level that does not activate the RF tag 301 that receives the radio waves. Therefore, by reducing the strength of the radio waves emitted from the side antenna 161 and leaking outside the storage section 100 through the opening 110, the RF tag reading device 1 is able to obtain only the information read from the RF tag 301 inside the storage section 100.

[0044] In the above-described first embodiment, an example was shown in which the upper end of right side portion 124 has a constant height from one end to the other end, and the angle between the upper end and the other end is a right angle. However, as long as radio waves within the range of the diagonal dashed line slanting upward to the right in FIG. 8 do not leak beyond the upper end and the other end of right side portion 124, the portion where the upper end and the other end of right side portion 124 meet may be rounded.

[0045] In the above-described first embodiment, an example has been shown in which the RF tag reader 1 has the mounting plate 150 and the side storage limit plate 151, but the mounting plate 150 may be omitted, and the side storage limit plate 151 may be omitted. When neither the mounting plate 150 nor the side storage limit plate 151 is present, the space above the bottom antenna 160 and surrounded by the front part 121, the left side part 122, the back part 123, and the right side part 124 becomes the storage space.

[0046] Furthermore, in RF tag reading device 1, middle portion 1222 of left side portion 122 protrudes to the left. Even if middle portion 1222 is wide (even if the length of protrusion to the left is long), a cashier's device or the like can be placed on middle portion 1222. Furthermore, if middle portion 1222 is wide, the distance between side antenna 161 and side accommodation limit plate 151 becomes large. This makes it possible to use side antenna 161 with higher directivity, and the portion of right side portion 124 at the other end that protrudes forward from front portion 121 can be made shorter.

[0047] Furthermore, if the radio wave shielding layers 140, 141, 142, 143 and the radio wave absorbing layer 144 are thin, there is a possibility that weak radio waves may leak out of the housing unit 100 through the bottom surface portion 120, the front surface portion 121, the left side surface portion 122, the back surface portion 123, and the right side surface portion 124. However, there is no problem as long as the strength of these radio waves is at a level that does not activate the RF tag 301 outside the housing unit 100.

[0048] (First Comparative Example) FIG. 9 shows a second comparative example of the RF tag reader 1 of FIG. 1, in which the right side surface portion 124A includes a radio wave reflective layer 144A. The RF tag reader 2 in Fig. 9 differs from the RF tag reader 1 in Fig. 1 in that the right side surface portion 124A includes a radio wave reflecting layer 144A instead of a radio wave absorbing layer. In other respects, the configuration of the RF tag reader 2 is the same as the configuration of the RF tag reader 1. The side of the accommodation section 101 in the RF tag reader 2 is composed of a front section 121, a left side section 122, a rear section 123, and a right side section 124A. The right side section 124A includes a flat plate 134 and a radio wave reflecting layer 144A. The radio wave reflecting layer 144A covers the inner surface of the flat plate 134, for example.

[0049] In the example of FIG. 9, RF tag 301 is held by a person or the like outside near storage section 101 on the left side surface section 122 side, and RF tag 301 is located slightly higher than center section 1222 of side surface section 122. The radio wave emitted from the side antenna 161 is reflected by the radio wave reflecting layer 144A. The strength of this reflected wave may be large. When this reflected wave passes through the middle part 1222 of the side part 122 and leaks to the outside through the opening 110, the RF tag 301 located outside near the storage part 101 on the left side part 122 side may be activated by this reflected wave. In this case, the response radio wave transmitted from this external RF tag 301 is also reflected by the radio wave reflecting layer 144A and reaches the side antenna 161. For this reason, the acquisition part 212 may acquire information of the RF tag 301 even though the RF tag 301 is located outside the storage part 101.

[0050] On the other hand, in the RF tag reader 1 according to this embodiment, the radio waves radiated from the side antenna 161 are absorbed by the radio wave absorbing layer 144. Therefore, the radio waves do not reach the RF tag 301 located as shown in FIG. Even if the radio waves radiated from the side antenna 161 leak outside beyond the upper end of the right side portion 124, the strength of the radio waves is low and the RF tag 301 outside the storage portion 100 will not function. For this reason, in the RF tag reading device 1 according to this embodiment, the acquisition unit 212 does not acquire information on the RF tag 301 outside the storage portion 100.

[0051] Therefore, in the RF tag reader 1 according to this embodiment, it is essential that the right side surface portion 124 includes the radio wave absorbing layer 144. On the other hand, the bottom surface portion 120, the front surface portion 121, the left side surface portion 122, and the back surface portion 123 may include radio wave reflecting layers instead of radio wave absorbing layers. However, if the bottom surface 120, the front surface 121, the left side surface 122, and the back surface 123 include radio wave reflection layers in addition to the right side surface 124A, the radio waves (direct waves) radiated by the side antenna 161 may be reflected by the bottom surface 120, the front surface 121, the left side surface 122, the back surface 123, and the right side surface, and a multipath may occur due to the direct waves and the reflected waves. If a multipath occurs, the direct waves radiated from the side antenna 161 may interfere with the reflected waves, and an area where the strength of the radio waves is low may occur inside the storage unit. If an RF tag 301 is present in this area, the RF tag 301 may not operate, and the acquisition unit 212 may not be able to acquire information from the RF tag 301. For this reason, it is desirable that the bottom surface 120, the front surface 121, the left side surface 122, and the back surface 123 include radio wave absorbing layers.

[0052] Furthermore, if front portion 121, left side portion 122, and rear portion 123 include radio wave reflecting layers in addition to right side portion 124A, radio waves emitted from bottom antenna 160 may be reflected by front portion 121, left side portion 122, rear portion 123, and right side portion 124A, and a slightly strong radio wave may leak out of the housing portion through opening 110. This can be solved by reducing the radio wave output of bottom antenna 160. However, from this point of view as well, it is desirable for front portion 121, left side portion 122, and rear portion 123 to include radio wave absorbing layers rather than radio wave reflecting layers.

[0053] Second embodiment 10 is a vertical cross-sectional view of an example of an RF tag reader 3 according to the second embodiment of the present invention, which corresponds to a cross-sectional view taken along line BB in FIG. The RF tag reader 3 includes a storage unit 100 and a control unit 201 . The configuration of the accommodation unit 100 of the RF tag reader 3 according to the second embodiment is the same as the configuration of the accommodation unit 100 of the RF tag reader 1 according to the first embodiment. The radio wave output of the bottom antenna 160 and the side antenna 161 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. In the RF tag reader 3 according to the second embodiment, the RF tag 301 outside the storage section 100 may be activated by radio waves leaking to the outside from the opening 110.

[0054] The control unit 201 includes a transmission / reception unit 214, a determination unit 215, an acquisition unit 216, and an I / F (interface) 217. If the RF tag 301 has a function for transmitting RSSI, the transceiver 214 acquires information including the RSSI and the tag ID from the response radio wave when the bottom antenna 160 receives the response radio wave. In this case, the RSSI indicates the strength of the radio wave radiated from the bottom antenna 160 and received by the RF tag 301. Alternatively, when the bottom antenna 160 receives a response radio wave, the transmitting / receiving unit 214 obtains information including the strength of the response radio wave and the tag ID from the response radio wave.

[0055] Similarly, if the RF tag 301 has a function of transmitting RSSI, the transceiver 214 acquires information including the RSSI and the tag ID from the response radio wave when the side antenna 161 receives the response radio wave. In this case, the RSSI indicates the strength of the radio wave radiated from the side antenna 161 and received by the RF tag 301. Alternatively, when the side antenna 161 receives a response radio wave, the transmitting / receiving unit 214 obtains information including the strength of the response radio wave and the tag ID from the response radio wave.

[0056] If the RF tag 301 has the function of transmitting RSSI, the discrimination unit 215 discriminates whether the RF tag from which each RSSI was obtained is inside or outside the storage unit 100 based on the RSSI obtained from the response radio wave received by the bottom antenna 160 and the RSSI obtained from the response radio wave received by the side antenna 161. For example, when the RSSI acquired from the response radio wave received by the bottom antenna 160 is equal to or greater than a predetermined first threshold, the discrimination unit 215 determines that the RF tag 301 is inside the storage unit 100. Also, for example, when the RSSI acquired from the response radio wave received by the side antenna 161 is equal to or greater than a predetermined second threshold, the discrimination unit 215 determines that the RF tag 301 is inside the storage unit 100.

[0057] However, the radio waves radiated from the bottom antenna 160 may, for example, be reflected by the ceiling or diffracted around the periphery of the opening 110, and may reach the RF tag 301 around the RF tag reader 3 with a somewhat strong intensity. In such an environment, the first threshold value is set to a value that allows the discrimination unit 215 to reliably discriminate that the RF tag 301 is outside the storage unit 100. In this case, based only on the RSSI acquired from the response radio wave received by the bottom antenna 160, the discrimination unit 215 may erroneously determine that the RF tag 301 is outside the storage unit 100, even though the RF tag 301 is actually inside the storage unit 100. However, by appropriately setting the second threshold, the discrimination unit 215 can almost correctly determine that the RF tag 301 is inside the storage unit 100, based on the RSSI acquired from the response radio wave received by the side antenna 161.

[0058] Alternatively, the discrimination unit 215 discriminates whether the RF tag from which the intensities of the response radio waves were obtained is inside or outside the storage unit 100 based on the intensities of the response radio waves obtained from the response radio waves received by the bottom antenna 160 and the side antenna 161. For example, when the strength of the response radio wave acquired from the response radio wave received by the bottom antenna 160 is equal to or greater than a predetermined third threshold, the discrimination unit 215 determines that the RF tag 301 is inside the storage unit 100. Also, for example, when the strength of the response radio wave acquired from the response radio wave received by the side antenna 161 is equal to or greater than a predetermined fourth threshold, the discrimination unit 215 determines that the RF tag 301 is inside the storage unit 100. By appropriately setting the third threshold and the fourth threshold according to the environment in which the RF tag reading device 3 is used, the discrimination unit 215 can almost correctly determine whether the RF tag 301 is inside or outside the storage unit 100.

[0059] The acquisition unit 216 identifies each RF tag 301 based on the tag ID included in the information of the RF tag 301 acquired from the response radio waves received by the bottom antenna 160 and the side antenna 161, respectively, and acquires the information for each RF tag 301. For example, when the discrimination unit 215 discriminates that the RF tag 301 is inside the storage unit 100, the acquisition unit 216 acquires information read from the RF tag 301. This enables the RF tag reader 3 to acquire information about the RF tag 301 inside the storage unit 100. The I / F 217 transmits the information acquired by the acquisition unit 216 to an external device (such as a checkout device) and receives operation instructions from the external device.

[0060] In addition, the acquisition unit 216 may also acquire information about the RF tag 301 that the discrimination unit 215 has determined to be outside the storage unit 100, and the I / F 217 may transmit the information about the RF tag 301 to an external device together with information indicating whether the RF tag 301 is inside or outside the storage unit 100.

[0061] The storage unit 100 according to the second embodiment and the storage unit 100 according to the first embodiment have the same configuration. Therefore, hereinafter, the operation of the RF tag reader 3 according to the second embodiment will be described with reference to Figs. 7 and 8.

[0062] When the side antenna 161 receives a response radio wave transmitted from an RF tag 301 that receives radio waves within the range indicated by the diagonal dotted line sloping upward to the right in Figure 7, the discrimination unit 215 determines that the RF tag 301 is inside. The radio waves radiated from side antenna 161 pass over the upper end of rear portion 123 and the upper end of right side portion 124 and leak from opening 110 to the outside of housing portion 100. However, the upper end of rear portion 123 and the upper end of right side portion 124 are higher than the upper edge of side antenna 161. As a result, the strength of the radio waves leaking from opening 110 to the outside of housing portion 100 is lower than the strength of the radio waves inside housing portion 100. The upper end of the rear portion 123 and the upper end of the right side portion 124 are at a height that reduces the intensity of radio waves that extend beyond those upper ends and leak through the opening 110 to the outside of the storage portion 100 to a level that allows the discrimination unit 215 to determine that the RF tag 301 is outside when the side antenna 161 receives a response radio wave transmitted from the RF tag 301 that has been activated by the radio waves.

[0063] In addition, when the side antenna 161 receives a response radio wave transmitted from an RF tag 301 that has received radio waves within the range of the diagonal dashed line slanting upward to the right as shown in Figure 8, the discrimination unit 215 determines that the RF tag 301 is inside the storage unit 100. The radio waves radiated from side antenna 161 leak from the other end of right side portion 124 to the outside of housing portion 100 (i.e., leak from opening 110 to the outside of housing portion 100). However, the strength of the radio waves leaking from the other end of right side portion 124 is lower than the strength of the radio waves inside housing portion 100. In the RF tag reader 3 according to the second embodiment, the other end of the right side surface part 124 protrudes a predetermined length toward the front side beyond the front surface part 121. As a result, the strength of the radio waves leaking from the other end of the right side surface part 124 to the outside of the storage part 100 is reduced to a level at which the discrimination part 215 can discriminate that the RF tag 301 is outside when the side antenna 161 receives a response radio wave transmitted from the RF tag 301 that has been activated by the radio waves. In the second embodiment, the specified length in the present invention is a length that reduces the intensity of the radio waves leaking from the other end of the right side portion 124 to the outside of the storage portion 100 to a level at which the discrimination unit 215 determines that the RF tag 301 is outside when the side antenna 161 receives a response radio wave transmitted from the RF tag 301 outside the storage portion 100 that has been activated by the radio waves. Therefore, by reducing the strength of the radio waves emitted from the side antenna 161 and leaking outside the storage section 100 through the opening 110, the RF tag reading device 3 is able to obtain information read from the RF tag 301 inside the storage section 100.

[0064] If the radio wave shielding layers 140, 141, 142, 143 and the radio wave absorbing layer 144 were thin, the radio waves emitted from the bottom antenna 160 or the side antenna 161 could pass through the bottom portion 120, the front portion 121, the left side portion 122, the back portion 123, and the right side portion 124 and leak out of the storage portion 100. However, these radio waves are weak. Therefore, even if the RF tag 301 outside the storage portion 100 receives these radio waves and returns a response radio wave, the discrimination portion 215 can determine that the RF tag 301 is outside the storage portion 100.

[0065] (Modification) The RF tag reader 1 according to the first embodiment and the RF tag reader 3 according to the second embodiment described above are provided with a bottom antenna 160 and a side antenna 161. As a modification of these RF tag readers 1 and 3, it is also possible to provide an RF tag reader in which the bottom antenna 160 is not provided on the bottom part 120, and only the side antenna 161 is provided on the inner surface of the left side part 122. In these modified RF tag readers, the left side part 122 may not include either a radio wave absorbing layer or a radio wave reflecting layer.

[0066] (Third embodiment) Fig. 11 is a perspective view of an example of an RF tag reader 4 according to a third embodiment of the present invention. Fig. 12 is a cross-sectional view taken along line CC in Fig. 11. Fig. 13 is a cross-sectional view taken along line DD in Fig. 11. Fig. 14 is a top view of an example of a storage section 102 in the RF tag reader 4 in Fig. 11. The RF tag reader 4 includes a storage unit 102 and a control unit 200A.

[0067] As shown in Figures 11 to 14, the storage section 102 has a bottom section 120, a front section 121, a left side section 122A, a rear section 123A, a right side section 124, a mounting plate 150, a side storage limiting plate 151, a front storage limiting plate 152, a bottom antenna 160, a side antenna 161, and a front antenna 162. The accommodating unit 102 according to the third embodiment differs from the accommodating unit 100 according to the first embodiment in that it has a front accommodation limiting plate 152 and a front antenna 162. Accordingly, the configurations of the left side surface portion 122A and the back surface portion 123A of the accommodating unit 102 differ from the configurations of the left side surface portion 122 and the back surface portion 123 of the accommodating unit 100. In other respects, the accommodating unit 102 according to the third embodiment is the same as the accommodating unit 100 according to the first embodiment. The differences between the accommodating unit 102 and the accommodating unit 100 will be described below.

[0068] One end and the other end of the left side surface portion 122A are fixed to one end of the front surface portion 121 and one end of the rear surface portion 123A, respectively. The left side surface portion 122A has an upper portion 1223 in addition to a lower portion 1221 and a middle portion 1222. The upper portion 1223 stands vertically from the right edge of the middle portion 1222 to the middle portion 1222 (and the bottom surface portion 120). The lower portion 1221, the middle portion 1222, and the upper portion 1223 respectively include a flat plate 1321, a flat plate 1322, and a flat plate 1323. A radio wave shielding layer 142 covers, for example, the inner surfaces of the flat plates 1321, 1322, and 1323. The front side of upper portion 1223 (i.e., one end of left side surface portion 122A) is at the same height as the upper end of front portion 121. Upper portion 1223 gradually becomes higher from the front side toward the rear side. The rear side of upper portion 1223 (i.e., the other end of left side surface portion 122A) is at the same height as the upper end of rear portion 123. Therefore, the upper end of left side surface portion 122A (i.e., the upper end of upper portion 1223) is higher than the upper end of front portion 121.

[0069] The rear portion 123A faces the front portion 121. The rear portion 123A stands perpendicularly to the bottom portion 120 from the edge of the rear side of the bottom portion 120. As shown in FIG. 15, one end of the rear portion 123A has a shape that matches the shape of the other end (i.e., the rear side) of the left side portion 122A. That is, the rear portion 123A is composed of a higher portion near the other end and a lower portion near the one end. The upper end of the rear portion 123A has a constant height and is higher than the upper end of the front portion 121. Here, the upper end of the rear portion 123A refers to the portion near the other end excluding the portion near the one end of the rear portion 123 that is lowered. The back surface portion 123A includes a flat plate 133A and an electromagnetic wave absorbing layer 143A. The electromagnetic wave absorbing layer 143A covers the inner surface of the flat plate 133A, for example.

[0070] The right side surface portion 124 faces the left side surface portion 122A. One end of the right side surface portion 124 is fixed to the other end of the rear surface portion 123A. The other end of the right side surface portion 124 protrudes a predetermined length toward the front side beyond the front surface portion 121, and the other end of the front surface portion 121 is fixed between the one end and the other end of the right side surface portion 124. The upper end of the right side surface portion 124 has a constant height from one end to the other end, and this height is the same as the height of the upper end of the rear surface portion 123A. Therefore, the upper end of the right side surface portion 124 is higher than the upper end of the front surface portion 121.

[0071] The radio wave absorbing layer 143A included in the back surface portion 123A may cover the outer surface of the flat plate 133A instead of covering the inner surface of the flat plate 133A, or may be sandwiched between two flat plates. In this case, however, the flat plate on the inner surface side of the radio wave absorbing layer 143A must be made of a material that transmits radio waves. The left side surface portion 122A is an example of a first side surface portion of the present invention, and the right side surface portion 124 is an example of a second side surface portion of the present invention.

[0072] The front antenna 162 is an antenna installed on the inner surface of the front part 121. The front antenna 162 radiates radio waves for communicating with the RF tag 301 toward the direction of the rear part 123A (i.e., the rear side) and receives response radio waves transmitted from the RF tag 301. The front antenna 162 is, for example, a planar antenna or a sheet antenna. The front antenna 162 radiates, for example, circularly polarized radio waves, or radiates radio waves while switching between horizontally polarized waves and vertically polarized waves. For example, the upper edge of the front antenna 162 and the upper end of the front part 121 are at the same height. Here, the upper edge of the front antenna 162 refers to the highest position of the part of the front antenna 162 that radiates radio waves. No antenna for emitting radio waves for communicating with the RF tag 301 is provided on the back surface 123A and the right side surface 124.

[0073] The front storage limiting plate 152 is, for example, a rectangular flat plate. The front storage limiting plate 152 is vertically erected from the upper surface of the mounting plate 150 between the front antenna 162 and the bottom antenna 160, with a predetermined distance from the front portion 121. One end and the other end of the front storage limiting plate 152 are, for example, fixed to the side storage limiting plate 151 and the right side portion 124, respectively, and the width of the front storage limiting plate 152 is the same as the distance between the side storage limiting plate 151 and the right side portion 124.

[0074] The front storage limiting plate 152 is located between the front part 121 and the rear part 123A, and is disposed at a predetermined distance from the front part 121. The front storage limiting plate 152 divides the inside of the storage part 102 into a space between the front part 121 and the front storage limiting plate 152, and a space between the front storage limiting plate 152 and the rear part 123A. Here, the space between the front part 121 and the front storage limiting plate 152 is a space through which radio waves radiated from the front antenna 162 propagate while spreading up, down, left, and right. The space between the front storage limiting plate 152 and the rear part 123A is a storage space. The storage space is a space capable of storing part or all of the article 300 and / or the shopping basket 400. The side storage limiting plate 151 is an example of a first storage limiting portion of the present invention, the placement plate 150 is an example of a second storage limiting portion of the present invention, and the front storage limiting plate 152 is an example of a third storage limiting portion of the present invention.

[0075] A control unit 200A of an RF tag reader 4 according to the third embodiment differs from the control unit 200 of the RF tag reader 1 according to the first embodiment in that the control unit 200A controls the front antenna 162. The control unit 200A includes a transmission / reception unit 211A, an acquisition unit 212A, and an I / F (interface) 213A. The transmitting / receiving unit 211A controls the front antenna 162 in addition to the bottom antenna 160 and the side antenna 161. The transmitting / receiving unit 211A causes the bottom antenna 160, the side antenna 161, and the front antenna 162 to radiate, for example, circularly polarized radio waves, or when linear polarization is used, causes the bottom antenna 160, the side antenna 161, and the front antenna 162 to radiate radio waves while switching between horizontal polarization and vertical polarization at high speed. Furthermore, when the bottom antenna 160, the side antenna 161, and the front antenna 162 receive a response radio wave, the transmitting / receiving unit 211A obtains information including the tag ID from the response radio wave. The transmission / reception unit 211A may radiate radio waves from bottom antenna 160, side antenna 161, and front antenna 162 at different times, or may radiate radio waves simultaneously from bottom antenna 160, side antenna 161, and front antenna 162 if mutual interference between the radio waves radiated from bottom antenna 160, side antenna 161, and front antenna 162 can be ignored.

[0076] The RF tag 301 obtains the power necessary to operate by receiving radio waves transmitted from one or more of the bottom antenna 160, the side antenna 161, and the front antenna 162. 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. In the RF tag reading device 4, the upper end of the rear portion 123A and the upper end of the right side portion 124 are higher than the upper edge of the side antenna 161, so that the strength of the radio waves radiated from the side antenna 161, passing over the upper end of the rear portion 123A and the upper end of the right side portion 124 and leaking out of the storage portion 102 through the opening 110, is reduced to a level that will not activate the RF tag 301 outside the storage portion 102. In the RF tag reader 4, because the other end of the right side portion 124 protrudes a predetermined distance toward the front side beyond the front portion 121, and because the radio waves radiated from the side antenna 161 are attenuated while propagating through the space between the front portion 121 and the front storage limiting plate 152, the strength of the radio waves radiated from the side antenna 161 and leaking from the other end of the right side portion 124 to the outside of the storage portion 102 (i.e., the strength of the radio waves leaking from the opening 110 to the outside of the storage portion 102) is reduced to a level that does not activate the RF tag 301 outside the storage portion 102. If the RF tag 301 does not operate, it will not transmit a response radio wave, and the RF tag reader 4 will not acquire information from the RF tag 301 outside the storage portion 102. Therefore, when the side antenna 161 receives a response radio wave from the RF tag 301, the RF tag reader 4 can obtain only the information read from the RF tag 301 inside the storage section 102. In the third embodiment, the specified length and specified interval in the present invention are lengths and intervals that reduce the intensity of radio waves leaking from the other end of the right side portion 124 to the outside of the storage portion 102 to a level that does not activate the RF tag 301 that receives the radio waves.

[0077] Furthermore, the transmitting / receiving unit 211A causes the bottom antenna 160 to radiate radio waves of an intensity that does not activate the RF tag 301 outside the storage unit 102 due to the radio waves reflected from the ceiling and the radio waves diffracted around the periphery of the opening 110. Therefore, when the bottom antenna 160 receives the response radio waves, the RF tag reader 4 can obtain only the information read from the RF tag 301 inside the storage unit 102. In addition, because the upper end of rear portion 123A and the upper ends of left side portion 122A and right side portion 124 are higher than the upper edge of front antenna 162, the strength of the radio waves radiated from front antenna 162 and passing over the upper ends of rear portion 123A and left side portion 122A and right side portion 124 and leaking out of accommodating portion 102 through opening 110 is reduced to a level that does not activate an RF tag outside accommodating portion 102. For this reason, when front antenna 162 receives a response radio wave, RF tag reader 4 can obtain only information read from RF tag 301 inside accommodating portion 102.

[0078] The acquisition unit 212A identifies each RF tag 301 based on the tag ID contained in the information of the RF tag 301 acquired from the response radio waves received by the bottom antenna 160, the side antenna 161, and the front antenna 162, respectively, and acquires the information for each RF tag 301. The I / F 213A transmits information about each RF tag 301 identified by the acquisition unit 212A to an external device (such as an accounting device) and receives operating instructions for the RF tag reader 4 from an external device.

[0079] Fig. 16 shows an example of radio waves emitted from the front antenna 162 in the RF tag reader 4 of Fig. 11. The front antenna 162 receives response radio waves transmitted from the RF tag 301 that has received radio waves within the range indicated by the diagonal dashed line sloping upward to the right. Radio waves radiated from front antenna 162 may leak out of housing 102 through opening 110, over the top end of left side surface portion 122A, the top end of back surface portion 123A, and the top end of right side surface portion 124. However, the top end of left side surface portion 122A, the top end of back surface portion 123A, and the top end of right side surface portion 124 are higher than the upper edge of front antenna 162. As a result, the strength of the radio waves leaking out of housing 102 is lower than the strength of the radio waves inside housing 102. The upper end of the left side surface portion 122A, the upper end of the back surface portion 123A, and the upper end of the right side surface portion 124 are at a height that reduces the strength of radio waves that leak beyond those upper ends to outside the storage portion 102 to a level that does not activate the RF tag 301 outside the storage portion 102. Therefore, by reducing the strength of the radio waves emitted from the front antenna 162 and leaking outside the storage section 102 through the opening 110, the RF tag reading device 4 is able to obtain only the information read from the RF tag 301 inside the storage section 102.

[0080] Fig. 17 shows an example of radio waves emitted from the side antenna 161 in the RF tag reader 4 of Fig. 11. The side antenna 161 receives response radio waves transmitted from the RF tag 301 that has received radio waves within the range indicated by the diagonal dashed line sloping upward to the right. Radio waves radiated from side antenna 161 may pass over the upper end of rear portion 123A and the upper end of right side portion 124 and leak from opening 110 to the outside of housing portion 102. However, the upper end of rear portion 123A and the upper end of right side portion 124 are higher than the upper edge of side antenna 161. As a result, the strength of the radio waves that pass over the upper end of rear portion 123A and the upper end of right side portion 124 and leak from opening 110 to the outside of housing portion 102 is lower than the strength of the radio waves inside housing portion 102. The upper end of the rear portion 123A and the upper end of the right side portion 124 are at a height that reduces the strength of radio waves that extend beyond those upper ends and leak through the opening 100 to outside the storage portion 102 to a level that does not activate the RF tag 301 outside the storage portion 102.

[0081] Fig. 18 shows an example of radio waves radiated from the side antenna 161 and reaching the right side part 124 in the RF tag reader 4 of Fig. 11, as viewed from the right side of the RF tag reader 4. The RF tag 301 that receives radio waves within the range of the diagonal dashed line sloping upward to the right operates and transmits a response radio wave. The radio waves radiated from the side antenna 161 may leak from the other end of the right side portion 124 to the outside of the accommodating portion 102 (i.e., leak from the opening 110 to the outside of the accommodating portion 102). However, the other end of the right side portion 124 protrudes a certain length toward the front side beyond the front portion 121. Furthermore, the radio waves radiated from the side antenna 161 are attenuated while propagating through the space between the front portion 121 and the front accommodation limiting plate 152. As a result, the strength of the radio waves leaking from the other end of the right side portion 124 to the outside of the accommodating portion 102 is reduced to a level that does not activate the RF tag 301 that receives the radio waves. Therefore, by reducing the strength of the radio waves emitted from the side antenna 161 and leaking outside the storage section 102 through the opening 110, the RF tag reading device 4 is able to obtain only the information read from the RF tag 301 inside the storage section 102.

[0082] In the above-mentioned third embodiment, an example was shown in which the RF tag reader 4 has the mounting plate 150, the side storage limit plate 151, and the front storage limit plate 152, but the mounting plate 150 may be omitted, the side storage limit plate 151 may be omitted, and the front storage limit plate 152 may be omitted. When the mounting plate 150, the side storage limit plate 151, and the front storage limit plate 152 are all omitted, the space above the bottom antenna 160 and surrounded by the front part 121, the left side part 122A, the back part 123A, and the right side part 124 becomes the storage space.

[0083] Furthermore, if the radio wave shielding layers 140, 141, 142 and the radio wave absorbing layers 143A, 144 were thin, there would be a possibility that weak radio waves would leak out of the housing unit 102 through the bottom surface 120, the front surface 121, the left side surface 122A, the back surface 123A, and the right side surface 124. However, there would be no problem if the strength of these radio waves was at a level that did not activate the RF tag 301 outside the housing unit 102.

[0084] FIG. 19 is a diagram for explaining an example of the effect of the RF tag reader 4 according to the third embodiment. 19, there are six RF tags 301 inside the storage unit 102. The RF tags 301 are parallel to the bottom antenna 160 and stacked one on top of the other, with their longitudinal directions facing the front antenna 162. In this case, the RF tags 301 located at the top have a harder time receiving the radio waves radiated from the bottom antenna 160. Moreover, the RF tags 301 also have a harder time receiving the radio waves radiated from the front antenna 162. However, each RF tag 301 receives radio waves radiated from the side antenna 161 and transmits a response radio wave to the side antenna 161. Therefore, the acquisition unit 212A can acquire information on the six RF tags 301. A situation in which multiple RF tags 301 are stacked vertically in parallel with the bottom antenna 160 and their longitudinal directions are directed toward the side antenna 161 or the front antenna 162 may occur, for example, when the RF tags 301 are attached to a thin product such as clothing. According to the RF tag reader 4 of the third embodiment, antenna radio waves are emitted to the RF tag 301 in the storage unit 102 from three directions perpendicular to each other. Therefore, there is a low possibility that the information of the RF tag 301 in the storage unit 102 will not be read properly.

[0085] (Second Comparative Example) FIG. 20 shows a comparative example 5 of the RF tag reader 4 of FIG. 11, in which the back surface portion 123B includes a radio wave reflective layer 143B. The RF tag reader 5 in Fig. 20 differs from the RF tag reader 4 in Fig. 11 in that the back surface 123B includes a radio wave reflecting layer 143B instead of a radio wave absorbing layer. In other respects, the configuration of the RF tag reader 5 is the same as the configuration of the RF tag reader 4. The sides of the storage section 103 in the RF tag reader 5 are made up of a front section 121, a left side section 122A, a rear section 123B, and a right side section 124. The rear section 123B includes a flat plate 133A and a radio wave reflecting layer 143B. The radio wave reflecting layer 143B covers the inner surface of the flat plate 134, for example.

[0086] In the example of FIG. 20, RF tag 301 is held by a person or the like outside near housing portion 103 on the front portion 121 side, and RF tag 301 is located slightly higher than front portion 121. The radio wave emitted from the front antenna 162 is reflected by the radio wave reflecting layer 143B. The strength of this reflected wave may be large. When this reflected wave passes over the front part 121 and leaks to the outside through the opening 110, the RF tag 301 located outside near the storage part 103 on the front part 121 side may be activated by this reflected wave. In this case, the response radio wave transmitted from this external RF tag 301 is also reflected by the radio wave reflecting layer 143B and reaches the front antenna 162. For this reason, the acquisition part 212A may acquire information of the RF tag 301 even though the RF tag 301 is located outside the storage part 103.

[0087] On the other hand, in the RF tag reader 4 according to this embodiment, the radio waves radiated from the front antenna 162 are absorbed by the radio wave absorbing layer 143A. Therefore, the radio waves do not reach the RF tag 301 located as shown in FIG. Even if the radio waves radiated from the front antenna 162 leak out beyond the upper end of the rear part 123A, the strength of the radio waves is low and the RF tag 301 outside the storage part 102 will not function. For this reason, in the RF tag reading device 4 according to this embodiment, the acquisition part 212A does not acquire information on the RF tag 301 outside the storage part 102.

[0088] Therefore, in the RF tag reader 4 according to this embodiment, it is essential that the back surface portion 123A and the right side surface portion 124 respectively include the radio wave absorbing layer 143A and the radio wave absorbing layer 144. On the other hand, the bottom surface portion 120, the front surface portion 121, and the left side surface portion 122A may include a radio wave reflecting layer instead of a radio wave absorbing layer. However, if the bottom surface 120, the front surface 121, and the left side surface 122A include radio wave reflection layers in addition to the rear surface 123A and the right side surface 124, the radio wave (direct wave) radiated by the front antenna 162 may be reflected by the bottom surface 120, the front surface 121, the left side surface 122A, the rear surface 123A, and the right side surface 124, and a multipath may occur due to the direct wave and the reflected wave. If a multipath occurs, the direct wave radiated from the front antenna 162 may interfere with the reflected wave, and an area where the intensity of the radio wave is low may occur inside the storage unit. If an RF tag 301 is present in this area, the RF tag 301 may not operate, and the acquisition unit 212A may not be able to acquire information from the RF tag 301. For this reason, it is desirable that the bottom surface 120, the front surface 121, and the left side surface 122A include radio wave absorption layers.

[0089] Furthermore, if front portion 121 and left side portion 122A, in addition to rear portion 123A and right side portion 124, include radio wave reflecting layers, radio waves emitted from bottom antenna 160 may be reflected by front portion 121, left side portion 122A, rear portion 123A, and right side portion 124, causing a slightly strong radio wave to leak outside the housing portion through opening 110. This can be solved by reducing the radio wave output of bottom antenna 160. However, from this point of view as well, it is desirable for front portion 121 and left side portion 122A to include a radio wave absorbing layer rather than a radio wave reflecting layer.

[0090] (Fourth embodiment) 21 is a vertical cross-sectional view of an example of an RF tag reader 6 according to the fourth embodiment of the present invention. FIG 21 corresponds to a cross-sectional view taken along line CC in FIG. The RF tag reader 6 includes a storage unit 102 and a control unit 201A. The configuration of the accommodating section 102 of the RF tag reader 6 according to the fourth embodiment is the same as the configuration of the accommodating section 102 of the RF tag reader 4 according to the third embodiment. The radio wave outputs of the bottom antenna 160, the side antenna 161, and the front antenna 162 in the RF tag reader 6 according to the fourth embodiment are greater than those of the RF tag reader 4 according to the third embodiment. In the RF tag reader 6 according to the fourth embodiment, the RF tag 301 outside the storage section 102 may be activated by radio waves leaking to the outside from the opening 110.

[0091] A control unit 201A of an RF tag reader 6 according to the fourth embodiment differs from the control unit 201 of the RF tag reader 3 according to the second embodiment in that the control unit 201A controls a front antenna 162. The control of the bottom antenna 160 and the side antenna 161 is the same in the control unit 201A according to the fourth embodiment and the control unit 201 according to the second embodiment. The differences between control unit 201A and control unit 201 will be described below.

[0092] The transmitting / receiving unit 214A causes the front antenna 162 to radiate circularly polarized radio waves, or when linearly polarized waves are used, causes the front antenna 162 to radiate radio waves while switching between horizontally polarized waves and vertically polarized waves at high speed. If the RF tag 301 has a function for transmitting RSSI, the transceiver 214A acquires information including the RSSI and the tag ID from the response radio wave when the front antenna 162 receives the response radio wave. In this case, the RSSI indicates the strength of the radio wave radiated from the front antenna 162 and received by the RF tag 301. Alternatively, when the front antenna 162 receives a response radio wave, the transmitting / receiving unit 214A obtains information including the strength of the response radio wave and the tag ID from the response radio wave.

[0093] The transmission / reception unit 214A may cause bottom antenna 160, side antenna 161, and front antenna 162 to radiate radio waves at different times, or may cause bottom antenna 160, side antenna 161, and front antenna 162 to radiate radio waves simultaneously if mutual interference between the radio waves radiated from bottom antenna 160, side antenna 161, and front antenna 162 can be ignored.

[0094] The discrimination unit 215A identifies each RF tag 301 based on the tag ID included in the information of the RF tag 301 acquired from the response radio waves received by the bottom antenna 160, the side antenna 161, and the front antenna 162, respectively. If the RF tag 301 has the function of transmitting RSSI, the discrimination unit 215A discriminates whether the RF tag from which each RSSI was obtained is inside or outside the storage unit 102 based on the RSSI obtained from the response radio waves received by the bottom antenna 160, the RSSI obtained from the response radio waves received by the side antenna 161, and the RSSI obtained from the response radio waves received by the front antenna 162. For example, when the RSSI acquired from the response radio wave received by the bottom antenna 160 is equal to or greater than a predetermined first threshold, the discrimination unit 215A determines that the RF tag 301 is inside the storage unit 102. Also, for example, when the RSSI acquired from the response radio wave received by the side antenna 161 is equal to or greater than a predetermined second threshold, the discrimination unit 215A determines that the RF tag 301 is inside the storage unit 102. Also, for example, when the RSSI acquired from the response radio wave received by the front antenna 162 is equal to or greater than a predetermined third threshold, the discrimination unit 215A determines that the RF tag 301 is inside the storage unit 102.

[0095] However, for example, radio waves radiated from the bottom antenna 160 may be reflected by the ceiling or diffracted around the periphery of the opening 110, and may reach the RF tag 301 around the RF tag reader 6 with a somewhat strong intensity. In such an environment, the first threshold value is set to a value that allows the discrimination unit 215A to reliably discriminate that the RF tag 301 is outside the storage unit 102. In this case, based only on the RSSI acquired from the response radio wave received by the bottom antenna 160, the discrimination unit 215A may erroneously determine that the RF tag 301 is outside the storage unit 102, even though the RF tag 301 is actually inside the storage unit 102. However, by appropriately setting the second threshold value and / or the third threshold value, the discrimination unit 215A can almost correctly determine that the RF tag 301 is inside the storage unit 102, based on the RSSI acquired from the response radio wave received by the side antenna 161 and / or the RSSI acquired from the response radio wave received by the front antenna 162.

[0096] Alternatively, the discrimination unit 215A discriminates whether the RF tag from which the intensities of the response radio waves were obtained is inside or outside the storage unit 102 based on the intensities of the response radio waves obtained from the response radio waves received by the bottom antenna 160, the side antenna 161, and the front antenna 162. For example, when the strength of the response radio wave acquired from the response radio wave received by the bottom antenna 160 is equal to or greater than a predetermined fourth threshold, the discrimination unit 215A discriminates that the RF tag 301 is inside the storage unit 102. Also, for example, when the strength of the response radio wave acquired from the response radio wave received by the side antenna 161 is equal to or greater than a predetermined fifth threshold, the discrimination unit 215A discriminates that the RF tag 301 is inside the storage unit 102. Also, for example, when the strength of the response radio wave acquired from the response radio wave received by the front antenna 162 is equal to or greater than a predetermined sixth threshold, the discrimination unit 215A discriminates that the RF tag 301 is inside the storage unit 102.

[0097] By appropriately setting the fourth to sixth threshold values ​​according to the environment in which the RF tag reading device 6 is used, the discrimination unit 215A can almost correctly discriminate whether the RF tag 301 is inside or outside the storage unit 102.

[0098] When the discrimination unit 215A discriminates that the RF tag 301 is inside the storage unit 102, the acquisition unit 216A acquires information read from the RF tag 301. This enables the RF tag reader 6 to acquire information read from the RF tag 301 inside the storage unit 102. The I / F 217A transmits information acquired by the acquisition unit 216A to an external device (such as a checkout device) and receives operation instructions from an external device.

[0099] In addition, the acquisition unit 216A may also acquire information about the RF tag 301 that the discrimination unit 215A has determined to be outside the storage unit 102, and the I / F 217A may transmit the information about the RF tag 301 to an external device together with information indicating whether the RF tag 301 is inside or outside the storage unit 102.

[0100] The operation of the RF tag reader 6 according to the fourth embodiment will be described below with reference to FIGS. When the front antenna 162 receives a response radio wave transmitted from an RF tag 301 that receives radio waves within the range indicated by the diagonal dotted line sloping upward to the right in Figure 16, the discrimination unit 215A determines that the RF tag 301 is inside. The radio waves radiated from front antenna 162 pass over the upper end of left side surface portion 122A, the upper end of rear surface portion 123A, and the upper end of right side surface portion 124, and leak from opening 110 to the outside of housing portion 102. However, the upper end of left side surface portion 122A, the upper end of rear surface portion 123A, and the upper end of right side surface portion 124 are higher than the upper edge of front antenna 162. As a result, the strength of the radio waves leaking from opening 110 to the outside of housing portion 102 is lower than the strength of the radio waves inside housing portion 102. The upper ends of left side portion 122A, back portion 123A, and right side portion 124 are at a height that reduces the intensity of radio waves that extend beyond those upper ends and leak through opening 110 to the outside of storage portion 102 to a level that allows discrimination unit 215A to determine that RF tag 301 is outside when front antenna 162 receives a response radio wave transmitted from RF tag 301 that has been activated by the radio waves. Therefore, by reducing the strength of the radio waves emitted from the front antenna 162 and leaking outside the storage section 102 through the opening 110, the RF tag reading device 6 is able to obtain information read from the RF tag 301 inside the storage section 102.

[0101] When the side antenna 161 receives a response radio wave transmitted from an RF tag 301 that receives radio waves within the range indicated by the diagonal dotted line sloping upward to the right in Figure 17, the discrimination unit 215A determines that the RF tag 301 is inside. The radio waves radiated from side antenna 161 pass over the upper end of rear portion 123A and the upper end of right side portion 124 and leak from opening 110 to the outside of housing portion 102. However, the upper end of rear portion 123A and the upper end of right side portion 124 are higher than the upper edge of side antenna 161. As a result, the strength of the radio waves leaking from opening 110 to the outside of housing portion 102 is lower than the strength of the radio waves inside housing portion 102. The upper end of the rear portion 123A and the upper end of the right side portion 124 are at a height that reduces the intensity of radio waves that extend beyond those upper ends and leak through the opening 110 to the outside of the storage portion 102 to a level that allows the discrimination unit 215A to determine that the RF tag 301 is outside when the side antenna 161 receives a response radio wave transmitted from the RF tag 301 that has been activated by the radio waves.

[0102] In addition, when the side antenna 161 receives a response radio wave transmitted from an RF tag 301 that has received radio waves within the range of the diagonal dashed line slanting upward to the right as shown in Figure 18, the discrimination unit 215A determines that the RF tag 301 is inside the storage unit 102. The radio waves radiated from side antenna 161 leak from the other end of right side portion 124 to the outside of housing portion 102 (i.e., leak from opening 110 to the outside of housing portion 102). However, the strength of the radio waves leaking from the other end of right side portion 124 is lower than the strength of the radio waves inside housing portion 102. In the RF tag reader 6 according to this embodiment, the other end of the right side portion 124 protrudes a predetermined length toward the front side from the front portion 121. Furthermore, the radio wave radiated from the side antenna 161 is attenuated while propagating through the space between the front portion 121 and the front storage limiting plate 152. As a result, the strength of the radio wave leaking from the other end of the right side portion 124 to the outside of the storage portion 102 is reduced to a level at which the discrimination unit 215A can discriminate that the RF tag 301 is outside when the side antenna 161 receives a response radio wave transmitted from the RF tag 301 operated by the radio wave. That is, in the fourth embodiment, the predetermined length and the predetermined interval in the present invention are the length and interval that reduce the strength of the radio wave leaking from the other end of the right side portion 124 to a level at which the discrimination unit 215A can discriminate that the RF tag 301 is outside when the side antenna 161 receives a response radio wave transmitted from the RF tag 301 outside the storage portion 102 operated by the radio wave. Therefore, by reducing the strength of the radio waves emitted from the side antenna 161 and leaking outside the storage section 102 through the opening 110, the RF tag reading device 6 is able to obtain information read from the RF tag 301 inside the storage section 102.

[0103] If the radio wave shielding layers 140, 141, 142 and the radio wave absorbing layers 143A, 144 are thin, there is a possibility that weak radio waves may leak to the outside of the storage unit 102 by passing through the bottom surface portion 120, the front surface portion 121, the left side surface portion 122A, the back surface portion 123A, and the right side surface portion 124. However, even if the RF tag 301 outside the storage unit 102 returns a response radio wave in response to receiving these radio waves, the discrimination unit 215A can discriminate that the RF tag 301 is outside the storage unit 102.

[0104] Fifth embodiment Fig. 22 is a perspective view of an example of an RF tag reader 7 according to a fifth embodiment of the present invention. Fig. 23 is a cross-sectional view taken along line EE in Fig. 22. Fig. 24 is a cross-sectional view taken along line FF in Fig. 22. Fig. 25 is a top view of an example of a storage section 104 in the RF tag reader 7 of Fig. 22. The RF tag reader 7 includes a storage unit 104 and a control unit 200A. A control unit 200A of the RF tag reader 7 according to the fifth embodiment is the same as the control unit 200A of the RF tag reader 4 according to the third embodiment.

[0105] As shown in Figures 22 to 25, the storage section 104 has a bottom section 120, a front section 121, a left side section 122B, a rear section 123C, a right side section 124B, a mounting plate 150, a side storage limiting plate 151, a front storage limiting plate 152, a bottom antenna 160, a side antenna 161, and a front antenna 162. The shapes of left side surface portion 122B, rear surface portion 123C, and right side surface portion 124B of storage portion 104 are different from the shapes of left side surface portion 122A, rear surface portion 123A, and right side surface portion 124 included in storage portion 102. In other respects, storage portion 104 according to the fifth embodiment is the same as storage portion 102 according to the third embodiment. The differences between storage portion 104 and storage portion 102 will be described below.

[0106] One end and the other end of the left side surface portion 122B are fixed to one end of the front surface portion 121 and one end of the rear surface portion 123C, respectively. Unlike the left side surface portion 122A according to the third embodiment, the left side surface portion 122B is not divided into a lower portion, a middle portion, and an upper portion. The left side surface portion 122B is flat. The left side surface portion 122B includes a flat plate 132B and a radio wave shielding layer 142. The radio wave shielding layer 142 covers, for example, the inner surface of the flat plate 132B. The left side surface portion 122B stands perpendicular to the bottom surface portion 120 from the left edge of the bottom surface portion 120. The front side of the left side surface portion 122B (i.e., one end of the left side surface portion 122B) is at the same height as the upper end of the front surface portion 121. The upper end of the left side surface portion 122B gradually becomes higher from the front surface side toward the rear surface side. The rear surface side of the left side surface portion 122B (i.e., the other end of the left side surface portion 122B) is at the same height as the upper end of the rear surface portion 123C. Therefore, the upper end of the left side surface portion 122B is higher than the upper end of the front surface portion 121.

[0107] The rear portion 123C faces the front portion 121. The rear portion 123C is rectangular. One end and the other end of the rear portion 123C are fixed to the other end of the left side surface portion 122B and one end of the right side surface portion 124B, respectively. The back surface portion 123C includes a rectangular flat plate 133B and an electromagnetic wave absorbing layer 143C. The electromagnetic wave absorbing layer 143C covers, for example, the inner surface of the flat plate 133B. The rear portion 123C stands perpendicular to the bottom portion 120 from the rear edge of the bottom portion 120. The upper end of the rear portion 123C has a constant height from one end to the other end. The upper end of the rear portion 123C is higher than the upper end of the front portion 121.

[0108] The right side surface portion 124B faces the left side surface portion 122B. As shown in Fig. 26, the right side surface portion 124B is rectangular. Unlike the right side surface portion 124 according to the third embodiment, the right side surface portion 124B does not have a portion that protrudes further forward than the front surface portion 121. One end and the other end of the right side surface portion 124B are fixed to the other end of the rear surface portion 123C and the other end of the front surface portion 121, respectively. The right side surface portion 124B includes a rectangular flat plate 134A and an electromagnetic wave absorbing layer 144B. The electromagnetic wave absorbing layer 144B covers, for example, the inner surface of the flat plate 134A. Right side surface portion 124B stands perpendicular to bottom surface portion 120 from the right edge of bottom surface portion 120. The upper end of right side surface portion 124B has a constant height from one end to the other end, and this height is the same as the height of the upper end of back surface portion 123C. Therefore, the upper end of right side surface portion 124B is higher than the upper end of front surface portion 121.

[0109] Next, differences in the operation of the RF tag reader 7 according to the fifth embodiment from the operation of the RF tag reader 4 according to the third embodiment will be described. Fig. 26 shows an example of radio waves radiated from the side antenna 161 and reaching the right side part 124B in the RF tag reader 7 of Fig. 22, as viewed from the right side of the RF tag reader 7. The RF tag 301 that receives radio waves within the range of the diagonal dashed line sloping upward to the right operates and transmits a response radio wave.

[0110] Unlike the RF tag reader 4 according to the third embodiment, the front storage limit plate 152 is essential in the RF tag reader 7. The right side part 124B does not have a portion that protrudes further forward than the front part 121. However, the front storage limit plate 152 is disposed at a predetermined distance from the front part 121, and the side antenna 161 radiates radio waves toward the storage space between the front storage limit plate 152 and the rear part 123C. The radio waves radiated from the side antenna 161 reach the right side part 124B while spreading in the space between the front part 121 and the front storage limit plate 152. The radio waves spreading in the space between the front part 121 and the front storage limit plate 152 are attenuated while propagating through the space between the front part 121 and the front storage limit plate 152. If the distance between the front part 121 and the front storage limit plate 152 is sufficiently large, the strength of the radio waves that pass beyond the other end of the right side part 124B and leak from the opening 110 to the outside of the storage part 104 is reduced to a level that does not activate the RF tag 301 that receives the radio waves. Except for this point, the operation of the RF tag reader 7 according to the fifth embodiment is the same as the operation of the RF tag reader 4 according to the third embodiment.

[0111] In the fifth embodiment, the specified interval in the present invention is an interval that reduces the intensity of radio waves leaking from the other end of the right side portion 124B to the outside of the storage portion 104 to a level that does not activate the RF tag 301 that receives the radio waves. In addition, in the fifth embodiment, an example was shown in which the RF tag reading device 7 has a mounting plate 150, a side storage limit plate 151, and a front storage limit plate 152, but the mounting plate 150 may be omitted, and the side storage limit plate 151 may be omitted. In addition, in the above-mentioned fifth embodiment, an example was shown in which the upper end of right side portion 124B has a constant height from one end to the other end, and the angle between the upper end and the other end is a right angle, but as long as radio waves within the range of the diagonal dashed line slanting upward to the right in FIG. 26 do not leak beyond the upper end and the other end of right side portion 124B, the portion where the upper end and the other end of right side portion 124B meet may be rounded.

[0112] Sixth embodiment 27 is a vertical cross-sectional view of an example of an RF tag reader 8 according to the sixth embodiment of the present invention. Fig. 27 corresponds to a cross-sectional view taken along line EE in Fig. 22. The RF tag reader 8 includes a storage unit 104 and a control unit 201A. The accommodation section 104 of the RF tag reader 8 according to the sixth embodiment is the same as the accommodation section 104 of the RF tag reader 7 according to the fifth embodiment.

[0113] The radio wave outputs of the bottom antenna 160, the side antenna 161, and the front antenna 162 in the RF tag reader 8 according to the sixth embodiment are greater than those of the RF tag reader 7 according to the fifth embodiment. In the RF tag reader 8 according to the sixth embodiment, the RF tag 301 outside the storage section 104 may be activated by radio waves leaking to the outside from the opening 110. The configuration of a control unit 201A of an RF tag reader 8 according to the sixth embodiment is the same as the configuration of a control unit 201A of an RF tag reader 6 according to the fourth embodiment. Therefore, a description of the RF tag reader 8 according to the sixth embodiment will be omitted. In the sixth embodiment, the specified interval in the present invention is an interval that reduces the intensity of the radio waves emitted from side antenna 161 and leaking out of storage section 104 from the other end of right side section 124B to a level at which discrimination section 215A determines that RF tag 301 is outside when side antenna 161 receives a response radio wave transmitted from an RF tag 301 outside storage section 104 that has been activated by the radio waves.

[0114] In addition, in the RF tag reading device of the present invention, it is possible to appropriately combine a configuration in which the RF tag 301 outside the storage unit does not operate and does not transmit response radio waves, and a configuration in which the RF tag 301 outside the storage unit operates and transmits response radio waves, but the RSSI or strength of the response radio waves is low, making it possible to determine that the RF tag 301 is outside. For example, the configuration can be such that RF tag 301 outside the storage section does not respond to the radio waves radiated from bottom antenna 160 and does not transmit response radio waves, whereas RF tag 301 outside the storage section responds to the radio waves radiated from front antenna 162 and side antenna 161 and transmits response radio waves, but the RSSI obtained from the response radio waves or the strength of the response radio waves is weak, making it possible to determine that RF tag 301 is outside.

[0115] In addition, in the above-described embodiment, an example in which one bottom antenna 160 is installed on the bottom portion 120 has been shown, but two or more bottom antennas may be installed on the bottom portion 120. Similarly, two or more front antennas may be installed on the front portion 121, and two or more side antennas may be installed on the left side portions 122, 122A, and 122B.

[0116] In the above embodiment, the left side surface portion is the first side surface portion of the present invention, and the right side surface portion is the second side surface portion of the present invention, but the right side surface portion may be the first side surface portion of the present invention, and the left side surface portion may be the second side surface portion of the present invention. That is, the side antenna 161 may not be provided on the left side surface portion, and may be provided on the right side surface portion.

[0117] In the above-described embodiment, the RF tag reader and the RF tag communicate with each other using radio waves in the UHF band of 860 to 960 MHz. However, the RF tag reader and the RF tag may communicate with each other using radio waves of other frequencies.

[0118] In addition, in the above-described embodiment, a product has been described as an example, but the product is not limited to a product, and may be other items such as samples, documents, medicines, etc. The RF tag reader according to the present invention can be used for other purposes as well as for self-checkouts.

[0119] As described above, according to the present invention, in an RF tag reader that has an opening at the top of a storage section and reads information from a passive RF tag inside the storage section when the opening is open, an antenna for communicating with the RF tag can be installed on the side of the storage section. Furthermore, with the RF tag reader according to the present invention, when an article or a shopping basket is inserted or removed from the storage section from the front side, it is easy to insert or remove the article or shopping basket into or from the storage section.

[0120] Furthermore, in the RF tag reader according to the present invention, even if the distance between the side antenna and the side storage limiting plate is increased, ease of use for the user is not reduced, and therefore a highly directional antenna can be used as the side antenna.

[0121] In addition, the RF tag reader according to the present invention, which has a bottom antenna, a front antenna, and a side antenna, radiates radio waves from the antennas in three mutually orthogonal directions toward the RF tag housed inside the storage unit, so that the RF tag reader can minimize missed reading of the RF tag housed inside the storage unit.

[0122] 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]

[0123] 1,3,4,6,7,8... RF tag reader of the present invention, 2,5... RF tag reader of comparative example, 100,102,103,104... storage section of the present invention, 101,103... storage section of comparative example, 110... opening, 120... bottom surface of the present invention, 121... front surface of the present invention, 122,122A,122B... left side surface of the present invention, 1221... lower part of the left side surface, 1222... middle part of the left side surface, 1223... upper part of the left side surface, 123,123A,123C... rear surface of the present invention, 123B... rear surface of comparative example, 124,124B... right side surface of the present invention, 124A... right side surface of comparative example, 130,131,133,133A,134,134A... flat plate, 1321,1322 , 1323...flat plate included in the left side portion, 140, 141, 142, 143...radio wave shielding layer, 143A, 143C, 144, 144B...radio wave absorbing layer, 143B, 144A...radio wave reflecting layer, 150...mounting plate, 151...side accommodation limiting plate, 152...front accommodation limiting plate, 160...bottom antenna, 161...side antenna, 162...front antenna, 200, 200A, 201, 201A...control unit, 211, 211A, 214, 214A...transmitting / receiving unit, 215, 215A...discrimination unit, 212, 212A, 216, 216A...acquisition unit, 213, 213A, 217, 217A...I / F (interface), 300...item, 301...RF tag, 400...shopping basket

Claims

1. An RF tag reading device that includes a storage unit having an opening at an upper portion through which an article having a passive RF tag attached thereto can be inserted and removed, and that reads information from an RF tag attached to an article stored inside the storage unit with the opening open, The storage section is A bottom surface portion including an electromagnetic wave absorbing layer and / or an electromagnetic wave reflecting layer; a front portion including an electromagnetic wave absorbing layer and / or an electromagnetic wave reflecting layer; a rear portion facing the front portion, the rear portion including a radio wave absorbing layer and / or a radio wave reflecting layer, no antenna being provided, and the upper end of the rear portion being higher than the upper end of the front portion and the upper edge of the side antenna; a side antenna for emitting radio waves for communicating with the RF tag and receiving response radio waves transmitted from the RF tag; a first side portion having one end and the other end fixed to one end of the front portion and one end of the rear portion, respectively, the first side portion having the side antenna installed on an inner surface thereof; a second side portion facing the first side portion, one end of which is fixed to the other end of the back portion and the other end of which projects forward beyond the front portion by a predetermined length, and the other end of the front portion is fixed between the one end and the other end, the second side portion including an electromagnetic wave absorbing layer, no antenna being installed, and the upper end of the second side portion being higher than the upper end of the front portion and the upper edge of the side antenna; Equipped with Since the upper end of the rear portion and the upper end of the second side portion are higher than the upper edge of the side antenna, and the other end of the second side portion protrudes a predetermined length toward the front side beyond the front portion, the strength of the radio waves radiated from the side antenna and leaking out of the storage portion through the opening is reduced, making it possible to obtain information about the RF tag inside the storage portion. RF tag reader.

2. a bottom antenna is provided on an upper surface of the bottom portion for emitting radio waves for communicating with the RF tag and for receiving response radio waves transmitted from the RF tag; The first side portion includes an electromagnetic wave absorbing layer and / or an electromagnetic wave reflecting layer.

2. The RF tag reader according to claim 1.

3. a first storage limiting portion located between the first side portion and the second side portion, the first storage limiting portion dividing the interior of the storage portion into a space between the first side portion and the first storage limiting portion through which radio waves radiated from the side antenna propagate while spreading up, down, left, and right, and a space between the first storage limiting portion and the second side portion which is a storage space capable of storing the item; a second accommodation limiting section located above the bottom section, the second accommodation limiting section dividing the interior of the accommodation section into a space between the bottom section and the second accommodation limiting section, through which radio waves radiated from the bottom antenna propagate while spreading, and a space above the second accommodation limiting section, which is the accommodation space; Equipped with The RF tag reader according to claim 2 .

4. An RF tag reading device that includes a storage unit having an opening at an upper portion through which an article having a passive RF tag attached thereto can be inserted and removed, and that reads information from an RF tag attached to an article stored inside the storage unit with the opening open, A bottom surface portion including an electromagnetic wave absorbing layer and / or an electromagnetic wave reflecting layer; a front antenna for emitting radio waves for communicating with the RF tag and for receiving response radio waves transmitted from the RF tag; A front part including an electromagnetic wave absorbing layer and / or an electromagnetic wave reflecting layer, the front antenna being disposed on an inner surface thereof; a rear portion facing the front portion, the rear portion including an electromagnetic wave absorbing layer, no antenna being provided, and the rear portion having an upper end higher than an upper end of the front portion and an upper edge of the front antenna; a third storage limiting section located between the front section and the rear section, the third storage limiting section dividing the interior of the storage section into a space between the front section and the third storage limiting section through which radio waves radiated from the front antenna propagate while spreading up, down, left, and right, and a space between the third storage limiting section and the rear section which is a storage space capable of storing the item; a side antenna for emitting radio waves for communicating with the RF tag and receiving response radio waves transmitted from the RF tag; a first side portion having one end and the other end fixed to one end of the front portion and one end of the rear portion, respectively, the first side portion including a radio wave absorbing layer and / or a radio wave reflecting layer, and the side antenna being installed on an inner surface of the first side portion; a second side portion facing the first side portion, one end of which is fixed to the other end of the back portion and the other end of which projects forward beyond the front portion by a predetermined length, and the other end of the front portion is fixed between the one end and the other end, the second side portion including an electromagnetic wave absorbing layer, no antenna being installed, and the upper end of the second side portion being higher than the upper end of the front portion and the upper edge of the side antenna; Equipped with Since the upper end of the rear portion, the upper end of the first side portion, and the upper end of the second side portion are higher than the upper edge of the front antenna, the strength of the radio waves radiated from the front antenna and leaking to the outside of the storage portion through the opening is reduced, making it possible to obtain information about the RF tag inside the storage portion, the upper end of the rear portion and the upper end of the second side portion are higher than the upper edge of the side antenna, the other end of the second side portion protrudes a predetermined length toward the front side beyond the front portion, and the radio waves radiated from the side antenna are attenuated while propagating through the space between the front portion and the third accommodation limiting portion, thereby reducing the intensity of the radio waves radiated from the side antenna and leaking outside the accommodation portion through the opening, thereby making it possible to obtain information about the RF tag inside the accommodation portion; RF tag reader.

5. An RF tag reading device that includes a storage unit having an opening at an upper portion through which an article having a passive RF tag attached thereto can be inserted and removed, and that reads information from an RF tag attached to an article stored inside the storage unit with the opening open, A bottom surface portion including an electromagnetic wave absorbing layer and / or an electromagnetic wave reflecting layer; a front antenna for emitting radio waves for communicating with the RF tag and for receiving response radio waves transmitted from the RF tag; A front part including an electromagnetic wave absorbing layer and / or an electromagnetic wave reflecting layer, the front antenna being disposed on an inner surface thereof; a rear portion facing the front portion, the rear portion including an electromagnetic wave absorbing layer, no antenna being provided, and the rear portion having an upper end higher than an upper end of the front portion and an upper edge of the front antenna; a third storage limiting section located between the front section and the rear section, the third storage limiting section dividing the interior of the storage section into a space between the front section and the third storage limiting section through which radio waves radiated from the front antenna propagate while spreading up, down, left, and right, and a space between the third storage limiting section and the rear section which is a storage space capable of storing the item; a side antenna for emitting radio waves for communicating with the RF tag and receiving response radio waves transmitted from the RF tag; a first side portion having one end and the other end fixed to one end of the front portion and one end of the rear portion, respectively, the first side portion including a radio wave absorbing layer and / or a radio wave reflecting layer, and the side antenna being installed on an inner surface of the first side portion; a second side portion facing the first side portion, one end of which is fixed to the other end of the rear portion and the other end of the front portion, the second side portion including an electromagnetic wave absorbing layer, no antenna being provided, and the upper end of the second side portion being higher than the upper end of the front portion and an upper edge of the side antenna; Equipped with Since the upper end of the rear portion, the upper end of the first side portion, and the upper end of the second side portion are higher than the upper edge of the front antenna, the strength of the radio waves radiated from the front antenna and leaking to the outside of the storage portion through the opening is reduced, making it possible to obtain information about the RF tag inside the storage portion, the upper end of the rear portion and the upper end of the second side portion are higher than the upper edge of the side antenna, and the radio waves radiated from the side antenna are attenuated while propagating through the space between the front portion and the third accommodation limiting portion, thereby reducing the intensity of the radio waves radiated from the side antenna and leaking out of the accommodation portion through the opening, thereby making it possible to obtain information about the RF tag inside the accommodation portion; RF tag reader.

6. 6. An RF tag reading device as described in claim 4 or 5, comprising a first storage limiting portion located between the first side portion and the second side portion, the first storage limiting portion dividing the interior of the storage portion into a space between the first side portion and the first storage limiting portion through which radio waves radiated from the side antenna propagate while spreading up, down, left, and right, and a space between the first storage limiting portion and the second side portion which is the storage space.

7. The opening allows a shopping basket containing the item to be inserted and removed, The storage space is capable of storing a part or all of the shopping basket.

6. The RF tag reader according to claim 3, wherein the RF tag reader is a device for reading an RF tag from a first input terminal.

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