Wireless tag communication device

Abstract

To provide a wireless tag communication device capable of determining with high accuracy whether or not a wireless tag is within a predetermined range.SOLUTION: A wireless tag communication device according to an embodiment is installed under a table on which an article attached with a wireless tag is placed. The wireless tag communication device includes: at least one antenna for communicating with the wireless tag; a reader / writer for processing communication between the wireless tag and the antenna; a stage for holding the antenna; and a drive unit for moving the stage. The stage holds the antenna at an angle so that a radiation surface of the antenna faces upward of a target area of the table on which the article is placed, and the drive unit moves the stage in a state in which the radiation surface of the antenna faces upward of the target area of the table and is tilted with respect to the table.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] Embodiments of the present invention relate to a wireless tag communication device.

Background Art

[0002] In recent years, in order to perform accounting processing, the use of wireless tags instead of barcodes that have been conventionally used has been increasing.

[0003] In such a system, a wireless tag is attached to an article, and the presence of the wireless tag is detected by a wireless tag communication device. When the wireless tag receives irradiation of electromagnetic waves, it transmits electromagnetic waves in response thereto. The wireless tag communication device detects the presence of the wireless tag by moving an antenna that radiates electromagnetic waves and receiving, with the antenna, the electromagnetic waves transmitted from the wireless tag that responds thereto.

[0004] The wireless tag communication device may also detect an unwanted wireless tag that exists away from the periphery of the target wireless tag. For this reason, the wireless tag communication device determines whether the wireless tag is within a predetermined range in order to exclude unwanted wireless tags.

[0005] In one example, the wireless tag communication device moves the antenna to measure the phase of the wireless tag, and determines whether the wireless tag is within a predetermined range based on the phase difference, which is the amount of change in phase.

[0006] In another example, the wireless tag communication device moves the antenna to acquire tag data of the wireless tag at a plurality of positions of the antenna, and uses a learned model generated by machine learning with this as an input to determine whether the wireless tag is within a predetermined range.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] It is desired that a wireless tag communication device can determine with high accuracy whether a wireless tag is within a predetermined range or not.

[0009] The problem to be solved by the present invention is to provide a wireless tag communication device that can determine with high accuracy whether a wireless tag is within a predetermined range or not.

MEANS FOR SOLVING THE PROBLEM

[0010] The wireless tag communication device according to the embodiment is installed below a table on which an article with a wireless tag attached is placed. The wireless tag communication device includes at least one antenna for communicating with the wireless tag, a reader / writer for processing the communication between the wireless tag and the antenna, a stage for holding the antenna, and a driving unit for moving the stage. The stage holds the antenna tilted so that the radiation surface of the antenna faces above the target area of the table on which the article is placed, and the driving unit moves the stage in a state where the radiation surface of the antenna faces above the target area of the table and is tilted with respect to the table.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011]

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Embodiments for Carrying Out the Invention

[0012] Hereinafter, with reference to the drawings, the wireless tag communication device according to the embodiment will be described.

[0013] (First Embodiment) First, with reference to FIGS. 1 to 3, the wireless tag communication device 100 according to the first embodiment will be described. FIG. 1 is a side view showing the wireless tag communication device 100 according to the first embodiment. FIG. 2 is a front view showing the wireless tag communication device 100 according to the first embodiment. FIG. 3 is a perspective view showing the wireless tag communication device 100 according to the first embodiment.

[0014] The wireless tag communication device 100 is installed under the table 10. The table 10 is a plate-like member held horizontally. An article 20 is placed on the table 10. For example, a shopping basket 40 containing the article 20 is placed on the table 10. Each article 20 is attached with a wireless tag 30. For example, the wireless tag 30 is an RFID (radio frequency identifier) tag.

[0015] The wireless tag communication device 100 includes a pair of antennas 110, a reader / writer 120, a stage 130, a drive unit 140, and a control unit 150.

[0016] The antenna 110 is a device for communicating with the wireless tag 30. The antenna 110 radiates electromagnetic waves. The antenna 110 also receives electromagnetic waves transmitted from the wireless tag 30 that responds to the electromagnetic wave radiation. The pair of antennas 110 are held by the stage 130 so that the radiation surfaces 111 face each other. Also, the pair of antennas 110 are arranged such that the straight line connecting the centers of the pair of antennas 110 is perpendicular to the moving axis (X-axis) of the drive unit 140. Further, the pair of antennas 110 are arranged at positions equidistant from the moving axis of the drive unit 140.

[0017] The reader / writer 120 is a device for processing the communication between the wireless tag 30 and the antenna 110. The reader / writer 120 transmits electromagnetic waves via the antenna 110 and detects the electromagnetic waves of the wireless tag 30 that responds thereto. The reader / writer 120 is composed of, for example, a computer.

[0018] The stage 130 includes a base plate 131, and columns 132 and 133. The base plate 131 is held horizontally by the drive unit 140. The columns 132 and 133 are erected on the base plate 131. The columns 132 and 133 hold the pair of antennas 110 in an inclined manner such that the radiation surfaces 111 of the pair of antennas 110 face each other.

[0019] The driving unit 140 includes a guide rail 141 and a motor 142. The guide rail 141 holds the stage 130 so that it can move linearly. For example, the guide rail 141 has a ball screw nut structure (not shown) inside. The nut of the ball screw nut structure holds the stage 130. The motor 142 rotates the screw shaft of the ball screw nut structure. The rotational movement of the screw shaft of the ball screw nut structure is converted into the linear movement of the nut of the ball screw nut structure.

[0020] Therefore, by rotating the motor 142, the stage 130 is linearly moved in the horizontal direction (X-axis direction). For example, by rotating the motor 142 forward, the stage 130 is linearly moved in the +X direction, and by rotating the motor 142 backward, the stage 130 is linearly moved in the -X direction. That is, by switching the rotational direction of the shaft of the motor 142, the stage 130 is reciprocally moved in the X-axis direction.

[0021] The control unit 150 controls the driving unit 140. That is, the control unit 150 controls the rotation of the shaft of the motor 142. The control unit 150 is composed of, for example, a computer. For example, each time a measurement is made, the control unit 150 linearly moves the stage 130 in one stroke in the +X direction or the -X direction.

[0022] Next, with reference to FIG. 4, the target area will be described. FIG. 4 is a schematic diagram for explaining the target area and is a plan view of the table seen from above.

[0023] On the upper surface of the table 10, a target area 11 is set. The target area 11 is an area where it is considered that the article 20 is placed. For example, the target area 11 is an area where it is considered that a shopping basket containing the article 20 is placed. Therefore, the drive unit 140 moves the stage 130 in a state where the radiation surfaces of the pair of antennas 110 face upward above the target area 11 of the table 10 and are inclined with respect to the table 10. Specifically, the center 12 of the target area 11 is located above the moving axis 143 of the drive unit 140. The moving axis 143 of the drive unit 140 is, for example, the central axis of the screw shaft of a ball screw nut structure. Also, the center 12 of the target area 11 is located on a straight line through which the midpoint of the pair of antennas 110 passes. That is, the drive unit 140 linearly moves the stage 130 along the moving axis 143 so that the stage 130 passes below the center 12 of the target area 11 set on the upper surface of the table 10.

[0024] Next, with reference to FIG. 5, the inside range of the basket will be described. FIG. 5 is a schematic diagram for explaining the inside range of the basket, and is a side view of the wireless tag communication device 100 as seen from the moving direction of the stage.

[0025] An inside range 13 of the basket is set on the table 10. The inside range 13 of the basket is a space where it is assumed that the article 20 can be placed. For example, the inside range 13 of the basket is a space where it is assumed that the article 20 placed in the shopping basket 40 can be placed. The inside range 13 of the basket is, for example, a three-dimensional space in the shape of a rectangular parallelepiped. The bottom surface of the inside range 13 of the basket coincides with the target area 11.

[0026] The inside range 13 of the basket is a range that satisfies the following requirements. A range that does not satisfy all of the following requirements is the outside of the inside range 13 of the basket (the outside range of the basket). · The height of the inside range 13 of the basket (the direction in which the product is placed as seen from the table 10) is in the range where the height H from the opening of the shopping basket 40 is up to 20 cm. · The width and depth of the inside range 13 of the basket include the shopping basket 40 and are sized to fit within the table 10. · The center 14 of the inside range 13 of the basket is located above the moving axis 143 of the drive unit 140.

[0027] The stage 130 holds the pair of antennas 110 tilted such that the radiation surfaces 111 of the pair of antennas 110 face upward of the target area 11 set on the upper surface of the table 10, i.e., the bottom surface of the inside area 13 of the basket. The direction of the radiation surface 111 of the antenna 110 is, for example, the maximum radiation direction of the electromagnetic wave 113 radiated by the antenna 110. The maximum radiation direction of the electromagnetic wave 113 can be said to be the direction of the normal line 114 erected at the center of the radiation surface 111 of the antenna 110. For example, the stage 130 holds the pair of antennas 110 tilted such that the intersection of the maximum radiation directions of the pair of antennas 110 coincides with the center 14 of the inside area 13 of the basket.

[0028] In the wireless tag communication device 100 according to the first embodiment, the antenna 110 is held tilted such that its radiation surface 111 faces upward (for example, the center of the inside area 13 of the basket) of the target area 11 set on the upper surface of the table 10. Therefore, the electromagnetic wave radiated from the antenna 110 is radiated more to the inside area 13 of the basket and less to the outside of the inside area 13 of the basket. Therefore, the wireless tag communication device 100 can determine with high accuracy whether the wireless tag 30 is inside the inside area 13 of the basket.

[0029] (Second Embodiment) With reference to FIGS. 6 to 8, the wireless tag communication device 200 according to the second embodiment will be described. FIG. 6 is a side view showing the wireless tag communication device 200 according to the second embodiment. FIG. 7 is a front view showing the wireless tag communication device 200 according to the second embodiment. FIG. 8 is a perspective view showing the wireless tag communication device 200 according to the second embodiment. In FIGS. 6 to 8, members with the same reference numerals as the members shown in FIGS. 1 to 5 are the same members, and detailed descriptions thereof are omitted. Hereinafter, the different parts will be mainly described. That is, parts not mentioned in the following description are the same as those in the first embodiment.

[0030] The wireless tag communication device 200 according to the second embodiment has a drive unit 240 and a control unit 250 instead of the drive unit 140 and the control unit 150 of the wireless tag communication device 100 according to the first embodiment. Further, the wireless tag communication device 200 according to the second embodiment has a sensor 260.

[0031] Similar to the drive unit 140 of the first embodiment, the drive unit 240 can move the stage 130 in a state where the radiation surfaces of the pair of antennas 110 face upward the target area 11 of the table 10 and are inclined with respect to the table 10. Further, the drive unit 240 can linearly move the stage 130 along the first movement axis (X axis) and the second movement axis (Y axis). The drive unit 240 has a first drive unit 241 that linearly moves the stage 130 along the first movement axis (X axis), and a second drive unit 242 that linearly moves the stage 130 along the second movement axis (Y axis). The first drive unit 241 has a guide rail 2411 and a motor 2412. The guide rail 2411 holds the stage 130 so as to be linearly movable along the first movement axis (X axis). The second drive unit 242 has a guide rail 2421 and a motor 2422. The guide rail 2421 holds the first drive unit 241 so as to be linearly movable along the second movement axis (Y axis).

[0032] Each configuration of the first drive unit 241 and the second drive unit 242 is the same as the configuration of the drive unit 140 of the first embodiment. For example, the guide rails 2411 and 2421 each have a ball screw nut structure (not shown) inside. The nut of the ball screw nut structure of the guide rail 2411 of the first drive unit 241 holds the stage 130. The nut of the ball screw nut structure of the guide rail 2421 holds the first drive unit 241. The motor 2412 of the first drive unit 241 rotates the screw shaft of the ball screw nut structure of the first drive unit 241 to linearly move the stage 130 along the first movement axis (X axis). The motor 2422 of the second drive unit 242 rotates the screw shaft of the ball screw nut structure of the second drive unit 242 to linearly move the entire second drive unit 242 along the second movement axis (Y axis).

[0033] The sensor 260 is for detecting the position along the second moving axis (Y-axis) of the article 20 placed on the table 10. For example, the sensor 260 is for detecting the position along the second moving axis (Y-axis) of the shopping basket 40 containing the article 20. For example, the sensor 260 is composed of a camera. The sensor 260 may be composed of other devices without being limited to a camera.

[0034] The control unit 250 controls the drive unit 240 based on the detection information of the sensor 260. Hereinafter, with reference to FIG. 9, the control operation by the control unit 250 in the wireless tag communication device 200 according to the second embodiment will be described. FIG. 9 is a flowchart showing the control operation by the control unit 250 in the wireless tag communication device 200 according to the second embodiment.

[0035] First, in ACT11, the control unit 250 acquires a photographed image from the camera which is the sensor 260.

[0036] Next, in ACT12, the control unit 250 detects the position (Y position) along the second moving axis (Y-axis) of the shopping basket 40 containing the article 20 from the acquired photographed image by image processing technology.

[0037] Subsequently, in ACT13, before the control unit 250 linearly moves the stage 130 along the first moving axis (X-axis) in the drive unit 240, the control unit 250 linearly moves the stage 130 along the second moving axis (Y-axis) (Y-direction movement) so that the center of the stage 130 (the midpoint between the pair of antennas 110) passes below the center of the shopping basket 40 along the first moving axis (X-axis).

[0038] Next, in ACT14, the control unit 250 linearly moves the stage 130 along the first moving axis (X-axis) (X-direction movement) in the drive unit 240.

[0039] Thereby, the stage 130 equipped with the antenna 110 passes below the center of the shopping basket 40 along the first moving axis (X-axis).

[0040] In the wireless tag communication device 200 according to the second embodiment, before the stage 130 equipped with the antenna 110 linearly moves along the first moving axis (X-axis), it linearly moves along the second moving axis (Y-axis) to a position passing below the center of the shopping cart 40, and then linearly moves along the first moving axis (X-axis). For this reason, the stage 130 equipped with the antenna 110 passes below the center of the shopping cart 40. Therefore, the electromagnetic wave radiated from the antenna 110 is radiated more to the shopping cart 40 and less to the outside of the shopping cart 40. For this reason, the wireless tag communication device 200 can determine with high accuracy whether the wireless tag 30 is inside the shopping cart 40 or not.

[0041] (Third Embodiment) With reference to FIGS. 10 to 12, the wireless tag communication device 300 according to the third embodiment will be described. FIG. 10 is a side view showing the wireless tag communication device 300 according to the third embodiment. FIG. 11 is a front view showing the wireless tag communication device 300 according to the third embodiment. FIG. 12 is a perspective view showing the wireless tag communication device 300 according to the third embodiment. In FIGS. 10 to 12, members with the same reference numerals as those shown in FIGS. 1 to 5 are the same members, and detailed descriptions thereof are omitted. Hereinafter, the description will focus on the differences. That is, the parts not mentioned in the following description are the same as those in the first embodiment.

[0042] The wireless tag communication device 300 according to the third embodiment has a drive unit 340 and a control unit 350 instead of the drive unit 140 and the control unit 150 of the wireless tag communication device 100 according to the first embodiment.

[0043] Similar to the driving unit 140 of the first embodiment, the driving unit 340 can move the stage 130 in a state where the radiation surfaces of the pair of antennas 110 face upward in the target area 11 of the table 10 and are inclined with respect to the table 10. Specifically, the driving unit 340 can move the stage 130 in a circular motion around the rotation center axis 343. That is, the driving unit 340 can rotate the stage 130 around the rotation center axis 343. The rotation center axis 343 is perpendicular to the horizontal plane. That is, the rotation center axis 343 is parallel to the vertical axis.

[0044] The driving unit 340 includes a motor 341 and a holding unit 342. The holding unit 342 holds the stage 130. Also, the holding unit 342 is fixed to the rotation shaft of the motor 341. The motor 341 rotates the holding unit 342 around the rotation center axis 343. Thereby, the stage 130 is moved in a circular motion around the rotation center axis 343.

[0045] Similar to the first embodiment, the stage 130 holds the pair of antennas 110 in an inclined manner such that the radiation surfaces 111 of the pair of antennas 110 face each other. That is, the stage 130 holds the pair of antennas 110 in an inclined manner such that the radiation surface 111 of the antenna 110 faces the center of the circular motion, that is, the rotation center axis 343 of the driving unit 340. Also, the pair of antennas 110 are arranged symmetrically with respect to the rotation center axis 343 of the driving unit 340. That is, the pair of antennas 110 are arranged with an angular position shift of 180 degrees around the rotation center axis 343 of the driving unit 340.

[0046] The control unit 350 controls the rotation of the motor 341. Thereby, the control unit 350 controls the rotation of the stage 130. For example, the control unit 350 rotates the stage 130 by 180 degrees each time a measurement is made.

[0047] In the third embodiment, although not shown, the range inside the basket is set in the same manner as in the first embodiment. That is, the range inside the basket is a range that satisfies the requirements described in the first embodiment. However, instead of being located above the moving axis 143 of the drive unit 140, the center of the range inside the basket is located on the rotation center axis 343 of the drive unit 340.

[0048] Also, the stage 130 holds the pair of antennas 110 tilted such that the radiation surfaces 111 of the pair of antennas 110 face above the bottom surface of the target area, that is, the range inside the basket, set on the upper surface of the table 10. Further, the stage 130 holds the pair of antennas 110 tilted such that the intersection of the maximum radiation directions of the pair of antennas 110 coincides with the center of the range inside the basket.

[0049] In the wireless tag communication device 300 according to the third embodiment, the antenna 110 is held tilted such that its radiation surface 111 faces the rotation center axis 343 of the drive unit 340. For this reason, the electromagnetic waves radiated from the antenna 110 are radiated more to the range inside the basket whose center is located on the rotation center axis 343 and less to the outside of the range inside the basket. For this reason, the wireless tag communication device 300 can determine with high accuracy whether the wireless tag 30 is inside the range inside the basket.

[0050] (Fourth Embodiment) With reference to FIGS. 13 to 15, the wireless tag communication device 400 according to the fourth embodiment will be described. FIG. 13 is a side view showing the wireless tag communication device 400 according to the fourth embodiment. FIG. 14 is a front view showing the wireless tag communication device 400 according to the fourth embodiment. FIG. 15 is a perspective view showing the wireless tag communication device 400 according to the fourth embodiment. In FIGS. 13 to 15, members denoted by the same reference numerals as those of the members shown in FIGS. 10 to 12 are the same members, and their detailed description will be omitted. Hereinafter, the description will focus on the different parts. That is, the parts not touched upon in the following description are the same as those in the third embodiment.

[0051] The wireless tag communication device 400 according to the fourth embodiment has a different arrangement of the pair of antennas 110 compared to the wireless tag communication device 300 according to the third embodiment. Other configurations of the wireless tag communication device 400 according to the fourth embodiment are the same as those of the wireless tag communication device 300 according to the third embodiment.

[0052] Also in the wireless tag communication device 400 according to the fourth embodiment, the stage 130 holds the pair of antennas 110 tilted such that the radiation surface 111 of the antenna 110 faces the center of the circumferential movement, that is, the rotation center axis 343 of the drive unit 340. However, in the wireless tag communication device 400 according to the fourth embodiment, the pair of antennas 110 are arranged with an angular position centered on the rotation center axis 343 of the drive unit 340 shifted by 90 degrees. In response to such an arrangement of the pair of antennas 110, for example, the control unit 350 rotates the stage 130 by 270 degrees each time a measurement is made.

[0053] Also in the wireless tag communication device 400 according to the fourth embodiment, similar to the wireless tag communication device 300 according to the third embodiment, the antenna 110 is held tilted such that its radiation surface 111 faces the rotation center axis 343 of the drive unit 340. For this reason, the electromagnetic waves radiated from the antenna 110 are radiated more within the basket range centered on the rotation center axis 343 and less outside the basket range. For this reason, the wireless tag communication device 300 can determine with high accuracy whether the wireless tag 30 is within the basket range.

[0054] In the above embodiments, an example in which the wireless tag communication device has a pair of antennas has been described. However, the number of antennas included in the wireless tag communication device is not limited to this. The wireless tag communication device may have one antenna or may have three or more antennas. That is, the wireless tag communication device only needs to have at least one antenna.

[0055] Although some embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention and are included in the invention described in the claims and the equivalent scope thereof.

Explanation of Reference Numerals

[0056] 10…Table, 11…Target area, 12…Center of the target area, 13…Range within the basket, 14…Center of the range within the basket, 20…Article, 30…Wireless tag, 100…Wireless tag communication device, 110…Antenna, 111…Radiating surface, 113…Electromagnetic wave, 114…Normal, 120…Reader / writer, 130…Stage, 131…Base plate, 132…Support column, 133…Support column, 140…Drive unit, 141…Guide rail, 142…Motor, 143…Moving axis, 150…Control unit, 200…Wireless tag communication device, 240…Drive unit, 241…Drive unit, 2411…Guide rail, 2412…Motor, 242…Drive unit, 2421…Guide rail, 2422…Motor, 250…Control unit, 260…Sensor, 300…Wireless tag communication device, 340…Drive unit, 341…Motor, 342…Holding unit, 343…Rotation center axis, 350…Control unit, 400…Wireless tag communication device.

Claims

1. A wireless tag communication device installed under a table on which an article with a wireless tag is placed, at least one antenna for communicating with the wireless tag, a reader / writer for processing the communication between the wireless tag and the antenna, a stage for holding the antenna in an inclined manner such that the radiation surface of the antenna faces upward of a target area of the table on which the article is placed, a driving unit for moving the stage while the radiation surface of the antenna faces upward of the target area of the table and is inclined with respect to the table, A wireless tag communication device comprising the above.

2. The at least one antenna includes a first antenna and a second antenna, The stage holds the first antenna and the second antenna in an inclined manner such that the radiation surfaces of the first antenna and the second antenna face each other, The wireless tag communication device according to Claim 1.

3. The driving unit linearly moves the stage along a first axis such that the stage passes below the center of the target area of the table on which the article is placed, The wireless tag communication device according to Claim 1.

4. The driving unit is capable of linearly moving the stage along a first axis and a second axis, a sensor for detecting the position of the article placed on the table, a control unit for controlling the driving unit based on the detection information of the sensor, and further comprising, before linearly moving the stage along the first axis, the control unit linearly moves the stage along the second axis such that the stage passes below the center of the article along the first axis, The wireless tag communication device according to Claim 1.

5. The driving unit moves the stage in a circular motion, The stage holds the antenna in an inclined manner such that the radiation surface of the antenna faces the center of the circular motion, The wireless tag communication device according to Claim 1.

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