Wireless tag

Abstract

A first objective of the present invention is to provide a wireless tag with which it is possible to calculate the distance between the wireless tag and a wireless device and to read information about an article.　This wireless tag is for use for attachment to an article, is equipped with a clock, calculates the distance to a wireless device on the basis of the propagation time of information or a signal between the tag and the wireless device as obtained using the clock, and enables a reading device to read information about the article.

Description

wireless tag

[0001] The present invention relates to a wireless tag and method.

[0002] In order to expand self-checkouts and prevent shoplifting, tags such as RFID tags are attached to products (see, for example, Patent Document 1). These tags store product information and the like, and when the product is within a predetermined distance from a reader provided at a security gate, for example, the stored product information and the like are acquired by the reader.

[0003] Japanese Patent Application Laid-Open No. 2004-062643

[0004] A first object of the present invention is to provide a wireless tag that can calculate the distance between the wireless tag and a wireless device and that can read information about an article. A second object of the present invention is to provide a method for calculating the distance between the wireless tag and a wireless device.

[0005] The present invention addresses the following problems: [1] A wireless tag that is used to be attached to an article, includes a clock, and calculates the distance to a wireless device based on the propagation time of information or signals from the wireless device obtained using the clock, and is capable of reading information about the article using a reader; [2] The wireless tag described in [1] above, which calculates the distance to each of a plurality of wireless devices based on the propagation time of information or signals from each of a plurality of wireless devices, and identifies the position of the wireless tag or article based on the calculated distances to each of the plurality of wireless devices; [3] The wireless tag described in [1] or [2] above, which executes a predetermined function using power obtained from electromagnetic waves received from the wireless device and / or the reader; [4] The wireless tag described in any of [1] to [3] above, which includes a battery that supplies power to the clock; [5] The wireless tag described in any of [1] to [4] above, which calculates the time difference between the wireless device and the wireless tag by communicating between the wireless device and the wireless tag, and corrects the time on the clock based on the calculated time difference; [6] A wireless tag according to any one of [1] to [5], which calculates a phase difference between the clocks of the wireless device and the wireless tag by communicating between the wireless device and the wireless tag, and corrects the phase in the wireless tag based on the calculated phase difference; [7] An article to which a wireless tag according to any one of [1] to [6] is attached; [8] A method for calculating a distance between a wireless tag and a wireless device based on a wireless tag having a clock and the propagation time of information or a signal between the wireless device and the wireless tag; [9] A method according to [8], which calculates a distance between each of a plurality of wireless devices and the wireless tag based on the propagation time of information or a signal between each of the plurality of wireless devices and the wireless tag, and specifies the position of the wireless tag based on the calculated distance between each of the plurality of wireless devices and the wireless tag;

[10] A method according to [8] or [9], in which a wireless tag is attached to an article, and a reading device reads information about the article stored in the wireless tag;

[11] A method according to

[10] , in which a reading device reads information about the article stored in the wireless tag when the wireless tag is located in a predetermined area;

[12] The method according to

[10] or

[11] , wherein the article is a commodity, the reading device reads information about the commodity stored in the wireless tag, and the computer device outputs the price of the commodity based on the read information about the commodity;This can be achieved by:

[0006] According to a first effect of the present invention, it is possible to provide a wireless tag that can calculate the distance between the wireless tag and a wireless device and that can read information about an article. According to a second effect of the present invention, it is possible to provide a method for calculating the distance between the wireless tag and a wireless device.

[0007] FIG. 1 is a block diagram showing a configuration of a system according to an embodiment of the present invention. FIG. 2 is a block diagram showing a configuration of a wireless device according to an embodiment of the present invention. FIG. 3 is a block diagram showing a configuration of a wireless tag according to an embodiment of the present invention. FIG. 4 is a block diagram showing a configuration of a server device according to an embodiment of the present invention. FIG. 5 is a diagram explaining an example of a usage mode of a system according to an embodiment of the present invention. FIG. 6 is a diagram showing a flowchart of payment processing according to an embodiment of the present invention. FIG. 7 is a diagram showing a flowchart of distance calculation processing according to an embodiment of the present invention. FIG. 8 is a diagram showing a flowchart of position identification processing according to an embodiment of the present invention. FIG. 9 is a diagram showing a flowchart of product order identification processing according to an embodiment of the present invention. FIG. 10 is a diagram showing a position management table according to an embodiment of the present invention.

[0008] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The following description of the effects of the present invention is one aspect of the effects of the embodiments of the present invention and is not limited to those described herein. The order of the processes constituting the flowcharts described below is random as long as no contradictions or inconsistencies occur in the process content. Furthermore, it is also possible to omit some of the processes constituting the flowcharts or add new processes to the processes constituting the flowcharts as long as no contradictions or inconsistencies occur in the process content. Furthermore, the device that executes each process constituting the flowcharts can be changed to another device as long as this does not violate the spirit of the present invention. In this case, the process content can be changed so as not to cause contradictions or inconsistencies in the process content.

[0009] The wireless tag of the present invention can be applied to the following systems. FIG. 1 is a block diagram showing the configuration of a system according to an embodiment of the present invention. As shown in the figure, the system 10 is composed of multiple wireless devices 1a to 1z and a wireless tag 2a. The wireless tag 2a is provided on an item. FIG. 1 shows an example in which the wireless tag 2a is provided on a product 2, which is an item. The system 10 may also include a server device 3, a reader 4, an accounting terminal 5, and a communication network 6.

[0010] The system 10 can be applied to retail stores that handle a variety of different types of products, such as convenience stores, supermarkets, electronics retailers, clothing stores, stationery stores, general merchandise stores, and cooking equipment stores.

[0011] The item is not particularly limited as long as it is a tangible object. The term "item" encompasses merchandise, and the wireless tag 2a can be attached to merchandise intended for sale to customers, but the wireless tag 2a can also be attached to items not intended for sale. For example, in a merchandise sales area, by attaching the wireless tag 2a to an exhibit (such as a doll placed for merchandise promotion) other than merchandise, it becomes possible to detect the location of the wireless tag 2a or the exhibit and obtain information about the exhibit with a reading device. Also, for example, by attaching the wireless tag 2a to stationery in the workplace, it becomes possible to detect the location of the wireless tag 2a or the stationery and obtain information about the stationery with a reading device, which can be used for stationery management. In this way, the wireless tag 2a can be applied to a wide variety of items, and the uses and functions of the items are not limited.

[0012] Wireless devices 1a-1z and wireless tag 2a can be directly connected for communication without going through communication network 6. Wireless devices 1a-1z can be connected for communication with server device 3 via communication network 6. Furthermore, wireless tag 2a and accounting terminal 5 can each be directly connected for communication with reader 4 without going through communication network 6. Accounting terminal 5 can be connected for communication with server device 3 via communication network 6.

[0013] The wireless device 1 is a device for identifying the position of the wireless tag 2a. The wireless device 1 is also a reference device for synchronizing the clocks of the wireless tags 2a, and one wireless device 1 can function as a wireless device for multiple wireless tags 2a. Furthermore, even if a device functions as a wireless tag 2a for one wireless device 1, it can also function as a wireless device for other wireless tags. Because the wireless device 1 is a reference device for synchronizing the clocks of the wireless tags 2a, it is preferable that the wireless device 1 have a clock with higher accuracy.

[0014] Furthermore, a pyramidal relationship may be formed by having multiple wireless tags 2a for one wireless device 1, and each of these multiple wireless tags 2a functioning as a wireless device for multiple other wireless tags.

[0015] A wireless device 1 according to the present invention will now be described. Fig. 2 is a diagram showing the configuration of a wireless device according to an embodiment of the present invention. The wireless device 1 includes a control unit 11, an RF chip 12, and an oscillator 13. The RF chip 12 includes a clock 12a and a phase detector 12b. In addition to the control unit 11, the RF chip 12, the oscillator 13, the clock 12a, and the phase detector 12b, the wireless device 1 may include other components as necessary.

[0016] The control unit 11 is not particularly limited, but may be, for example, a microcomputer (microcontroller). The control unit 11 executes programs based on programs and data. The RF chip 12 receives and transmits radio signals. The data received by the RF chip 12 is subjected to arithmetic processing by the control unit 11.

[0017] The oscillator 13 oscillates at a predetermined frequency and outputs a signal that provides operational timing for each component of the device. An atomic oscillator or a quartz oscillator can be used as the oscillator 13. The clock 12a uses the output signal from the oscillator 13 as a source of oscillation to clock and output the time. The control unit 11 controls the clock 12a to transmit the time clocked by the clock 12a to the wireless tag 2a via the RF chip 12. The phase detector 12b detects the phase of the carrier wave that constitutes the information received from the wireless tag 2a, and detects the phase of the signal oscillated by the oscillator 13 in the wireless device 1.

[0018] One or more wireless devices 1 (wireless devices 1a to 1z) are installed in the system 10. The installation location of the wireless device 1 is not particularly limited, but the wireless device 1 may be installed inside or outside a store where the wireless tag 2a is used. In this case, some of the multiple wireless devices 1 may be installed outdoors, and the other wireless devices 1 may be installed indoors. When multiple wireless devices 1 are installed, the positional relationship between the multiple wireless devices 1 is not particularly limited. For example, to cover an area where the position of the wireless tag 2a can be identified, the multiple wireless devices 1 may be arranged at intersections of a grid. Alternatively, the wireless devices 1 may be arranged at predetermined intervals on corner pillars or walls of the store where the wireless tag 2a is used, or on the perimeter of the store and its parking lot. Furthermore, from the viewpoint of reducing obstacles that affect communication, it is preferable to install multiple wireless devices 1 inside a store where the wireless tag 2a is installed.

[0019] It is preferable that the wireless device 1 is installed at a fixed location where the installation position can be identified. For example, the wireless device 1 may be installed on a transmission tower supporting a power transmission line. Note that the installation position information of the wireless device 1 may be stored in the wireless tag 2a, the server device 3, or the like in association with identification information that can identify the wireless device 1.

[0020] In the system 10 using the wireless tag of the present invention, the wireless device 1 may have not only the function of the wireless device 1 but also the function of the reader 4 described later.

[0021] The wireless tag 2a will now be described. The size and shape of the wireless tag 2a are not particularly limited as long as it is attached to an item. Furthermore, the method of attaching the wireless tag 2a to an item is also not particularly limited. The wireless tag 2a may be attached to the item or its wrapping, or the wireless tag 2a and the item may be tied together using a string or the like, or the wireless tag 2a may be hung on the item using a string, rubber, or the like. Furthermore, if the item is a commodity, the wireless tag may be attached to a product tag, price tag, or hanging price tag attached to the commodity.

[0022] The wireless tag 2a is not particularly limited as long as it is a tag-type tag that is capable of wireless communication, but is preferably an active RF tag or semi-active RF tag, which has a power source and a wide communication range. From the perspective of extending the life of the battery, which will be described later, a watch is supplied with power from a built-in battery, and data transmission and reception between the wireless tag 2a and the reader 3 involves converting signals received from the reader 4 into power, so a semi-active RF tag is preferred.

[0023] 3 is a block diagram showing the configuration of a wireless tag according to an embodiment of the present invention. The wireless tag 2a used in the present invention includes a microprocessor 21, a memory 22, an antenna 23, an RF chip 24, an oscillator 25, and a battery 26. The RF chip 24 includes a clock 24a and a phase detector 24b. In addition to these components, the wireless tag 2a may include other components as necessary.

[0024] The microprocessor 21 executes programs. The RF chip 24 receives and transmits radio signals. The data received by the RF chip 24 is subjected to arithmetic processing by the microprocessor 21.

[0025] The electromagnetic waves transmitted from the wireless device 1 or the reader 4 are received by the antenna 23. When the antenna 23 receives the electromagnetic waves, an electrical signal is generated in response. This allows the wireless tag 2a to receive power from the wireless device 1 or the reader 4.

[0026] When the wireless tag 2a receives power from the wireless device 1, the microprocessor 21 is started up, executes a program stored in the microprocessor 21, and transmits a wireless signal to the wireless device 1 via the RF chip 24 that can identify the time clocked by the clock 24a and the phase of the carrier wave.

[0027] Furthermore, when the wireless tag 2a receives power from the reader 4, the microprocessor 21 is activated and the information in the memory 22 can be transmitted to the reader 4. The memory 22 stores, for example, identification information that can identify the wireless tag 2a or identification information (also called product information) that can identify the product to which the wireless tag 2a is attached, and can transmit this information to the reader 4.

[0028] Furthermore, when the wireless tag 2a receives predetermined information from the reader 4, power is generated based on the received electromagnetic waves, which activates the microprocessor 21 and allows the received predetermined information to be written into the memory 22. The reader 4 is capable of not only reading information from the wireless tag 2a but also writing information into the wireless tag 2a, and therefore also functions as a writing device.

[0029] The battery 26 supplies power to the clock 24 a. By supplying power to the clock 24 a from the battery 26, the clock 24 a can continue to operate even if power is not supplied to the wireless tag 2 a by receiving electromagnetic waves from the wireless device 1 or the reader 4.

[0030] The oscillator 25 oscillates at a predetermined frequency and outputs a signal that provides operation timing for each component of the wireless tag 2a. An atomic oscillator or a quartz oscillator can be used as the oscillator 25. The clock 24a uses the output signal from the oscillator 25 as a source of oscillation to clock and output the time. The time clocked by the clock 24a is controlled by the microprocessor 21 to be transmitted to the wireless device 1 via the RF chip 24. The phase detector 24b detects the phase of the carrier wave that constitutes the information received from the wireless device 1, and detects the phase of the signal oscillated by the oscillator 25 in the wireless tag 2a.

[0031] Next, the server device of the present invention will be described. The server device 3 can acquire, from the wireless tag 2a, location information regarding the distance to the wireless device 1 calculated by a distance calculation process described below and / or the location of the wireless tag 2a identified by a position determination process described below. It is also possible to identify the location of the wireless tag 2a from the distances between each of the wireless devices 1 and the wireless tag 2a calculated by the distance calculation process. The location information of the wireless tag 2a is transmitted from the wireless tag 2a to the server device 3, for example, in association with identification information that can identify the wireless tag 2a and the time at which the location information was identified. The server device 3 then stores the location information in association with the time. Meanwhile, the server device 3 can transmit the location information of the wireless tag 2a to the accounting terminal 5.

[0032] The server device 3 may communicate with the wireless device 1 or the accounting terminal 5 via the communication network 6. The server device 3 may also communicate with the wireless device 1 or the accounting terminal 5 via an optical fiber installed alongside a transmission tower.

[0033] 4 is a block diagram showing the configuration of a server device according to an embodiment of the present invention. The server device 3 includes at least a control unit 31, a RAM 32, a storage unit 33, and a communication interface 34, which are connected to each other via an internal bus.

[0034] The control unit 31 is composed of a CPU and ROM, and executes programs stored in the storage unit 33 to control the server device 3. The control unit 31 also has an internal timer for measuring time. The RAM 32 is a work area for the control unit 31. The storage unit 33 is a memory area for saving programs and data. The control unit 31 reads out the programs and data from the RAM 32 and performs program execution processing based on information received from the wireless device 1, etc.

[0035] Next, we will explain the reader 4. The reader 4 is a device that reads product information about products stored in the wireless tag 2a. The reader 4 can be directly connected to both the wireless tag 2a and the accounting terminal 5 without going through the communication network 6.

[0036] An example of the reading device 4 is a well-known RFID (Radio Frequency Identification) reader. The RFID reader includes a control unit and an antenna, and reads product information as follows: First, radio waves are transmitted from the antenna of the RFID reader, which is the reading device 4. The radio wave is received by the wireless tag 2a, which activates the wireless tag 2a. The microprocessor 21 of the wireless tag 2a converts the product information stored in the memory 22 into a signal and transmits it from the antenna. The signal is received by the antenna of the RFID reader. The signal received by the RFID reader may be transmitted from the microprocessor 21 to the server device 3 or a management terminal. The reading device 4 may read product information related to each product stored in the wireless tag 2a, or may simultaneously read product information for multiple products arranged within a predetermined range.

[0037] Next, the accounting terminal 5 will be described. The accounting terminal 5 is a device that totals the payment amount based on the product information about the product read by the reading device 4. The accounting terminal 5 can communicate with the server device 3 via the communication network 6. The accounting terminal 5 can be either a conventional cash register operated by a store clerk or a conventional self-checkout register operated by a store clerk or a customer.

[0038] The accounting terminal 5 is configured to include, for example, a control unit, RAM, storage unit, communication interface, input unit, and display unit, all of which are connected by an internal bus. The control unit of the accounting terminal 5 is composed of a CPU and ROM, and executes programs stored in the storage unit to control the accounting terminal 5. The RAM is the work area of ​​the control unit. The storage unit is a memory area for saving programs and data. The control unit reads the programs and data from the RAM and performs program execution processing based on information received from the server device 3, etc.

[0039] The display unit of the accounting terminal 5 may be a touch panel whose display screen is equipped with a touch sensor. The touch panel may be contact-type or non-contact-type. The touch panel may also function as an input unit.

[0040] Next, a usage mode of the system according to an embodiment of the present invention will be described. FIG. 5 is a diagram illustrating an example of a usage mode of the system according to an embodiment of the present invention. FIG. 5 illustrates a case where the system 10 is applied to a store selling groceries. As shown in the figure, the system 10 includes wireless devices 1 at four corners of a store 40. A customer 41 enters and leaves the store 40 through a store entrance / exit 42. The store 40 includes a storage space 43 capable of storing products. Multiple storage spaces 43 may be provided. The storage space 43 may be, for example, a storage room or a storage shelf. Products 2 are stored within the storage space 43. Each product 2 is equipped with a wireless tag 2a. The store 40 also includes a reading device 4 for reading product information and an accounting terminal 5. A server device 3 may be provided inside the store 40 or outside the store 40.

[0041] [Payment Processing] Once the user 41 has placed all of the products 2 they wish to purchase in the basket or picked up all of the products 2 they wish to purchase, the user uses the reader 4 in the store 40 to have the reader 4 read the wireless tags 2a attached to the products and pay for the products. The payment processing will be described below. Figure 6 is a diagram showing a flowchart of the payment processing according to an embodiment of the present invention. It is preferable that the flowchart of the payment processing be executed periodically at predetermined time intervals (for example, every second).

[0042] First, the reader 4 determines whether the wireless tag 2a is located within the checkout area (step S1). The checkout area can be appropriately set by an administrator who manages or monitors the wireless tags 2a. The checkout area must be an area where communication between the wireless tag 2a and the reader 4 is possible when the wireless tag 2a is placed within the area, i.e., an area where the reader 4 can read the information from the wireless tag 2a. Furthermore, it is preferable to set the checkout area in a location where a customer can easily recognize that the area will allow the reader 4 to read product information when the customer places the product 2 or a basket containing the product 2 therein. For example, by placing the product 2 or a basket containing the product 2 on the checkout counter 44, the product 2 or the basket containing the product 2 can be placed in an area that meets the above-mentioned conditions for a checkout area.

[0043] In this case, it is possible to determine whether or not the customer is within the area where the product is to be checked out, based on the location information of the wireless tag 2a attached to the product 2 or the wireless tag attached to the basket containing the product 2. The location information of the wireless tag 2a will be described later.

[0044] In step S1, if it is determined that the wireless tag 2a is not located within the area where the product is to be checked out (NO in step S1), the process ends.

[0045] In step S1, if it is determined that the wireless tag 2a is located within the area where the merchandise is to be checked out (YES in step S1), the reader 4 reads the wireless tag 2a (step S2). Reading the wireless tag 2a means reading the merchandise information stored in the wireless tag 2a. There are no particular restrictions on the reading method. In step S2, the reader 4 reads the merchandise information from multiple wireless tags 2a within the area where the merchandise is to be checked out. At this time, the reader 4 transmits a signal to the wireless tag 2a, and the wireless tag 2a can transmit the merchandise information to the reader 4 using the power generated by this signal.

[0046] Next, the reading device 4 transmits the read product information to the accounting terminal 5 (step S3), and the accounting terminal 5 receives the read product information (step S4). The product information transmitted from the reading device 4 to the accounting terminal 5 may include the type (product ID) and quantity of the product read by the wireless tag 2a.

[0047] Next, the accounting terminal 5 totals the payment amount based on the read product information (step S5). The price of product 2 is pre-stored in the memory of the control unit of the accounting terminal 5 in association with the product type (product ID), and the payment amount can be totaled when the product ID and quantity are received. The total payment amount can be displayed on the display unit of the accounting terminal 5. The above "product price" is a concept that also includes the "total price of multiple products."

[0048] The user 41 performs payment processing (step S6). The payment processing in step S6 can be completed by inserting cash, a gift certificate, a gift card, or the like into the accounting terminal 5. It can also be performed using known payment methods, such as credit card payment, QR code (registered trademark, the same applies below), or electronic money payment. The payment processing in step S6 may be performed on the accounting terminal 5, or QR code payment or electronic money payment may be performed using a user terminal such as a smartphone or tablet used by the user.

[0049] Alternatively, instead of the payment process in step S6, the payment amount may be billed together with the electricity usage fee of the user 41. In this case, the payment amount or an accounting ID (described later) may be associated with identification information that can identify the user 41 and transmitted to the server device 3, and the server device 3 may add the payment amount to the electricity usage fee of the electric company with which the user 41 has a contract for a predetermined period. The predetermined period is not particularly limited, but may be, for example, one month, the same period as the period for which the user is billed for the electricity usage fee. This allows the user to consolidate payments.

[0050] The payment process executed at the accounting terminal 5 may be transmitted to the server device 3 in association with identification information (accounting ID) that can identify each transaction for each payment process and the product information for the transaction, and stored in the storage unit 33 of the server device 3.

[0051] Once the payment process is completed in step S6, payment completion information indicating that the payment has been completed is sent from the accounting terminal 5 to the reading device 4 (step S7). When the reading device 4 receives the payment completion information (step S8), the reading device 4 communicates with the wireless tag 2a and writes information indicating that the payment has been completed to the wireless tag 2a (step S9). By executing step S9, the payment process can be terminated. In step S9, the payment completion information is sent from the reading device 4 to the wireless tag 2a, and the power generated by this signal can be used to write the payment completion information to memory 22 in the wireless tag 2a.

[0052] When the writing is performed in step S9, a payment completion flag indicating that payment has been completed is set in the memory 22 of the wireless tag 2a. For a wireless tag 2a for which the payment completion flag is set, it is possible to prevent calculation of the distance from the wireless device 1 or to prevent measurement of the position of the wireless tag 2a. For example, even if a product 2 with a wireless tag 2a attached is taken outside the store, an alarm, which will be described later, is not issued, and it is possible to restrict acquisition of private information, such as the location outside the store, of the person who purchased the product.

[0053] After the payment process, the user 41 leaves the store 40. In this case, based on the identified location information of the product 2 or the wireless tag 2a, if the product 2 or the wireless tag 2a for which payment has not been completed is located outside the store 40 or has passed through the store entrance / exit 42, the system 10 can notify the store manager or the like by issuing an alarm or the like that the product 2 or the wireless tag 2a is outside a predetermined range. More specifically, alarm information indicating that the product 2 or the wireless tag 2a is outside the predetermined range can be transmitted to the computer device, and the alarm can be displayed on the computer device or an alarm can be sounded from a speaker provided in the computer device or an external speaker. The determination that the product 2 or the wireless tag 2a is located outside the store 40 or has passed through the store entrance / exit 42 can be made, for example, by the wireless device 1 or the server device 3 determining whether the product 2 or the wireless tag 2a is outside the predetermined range (outside the store 40) based on the location information of the wireless tag 2a.

[0054] [Distance Calculation Process] In the above payment process, the position information of the wireless tag 2a can be used to determine whether the wireless tag 2a is located within the area where the product is paid for. That is, the wireless tag 2a attached to the product 2 can identify the position of the wireless tag 2a (i.e., the product) by communicating with the wireless device 1 provided in the store 40. The position of the wireless tag 2a can be identified based on the calculated distance by calculating the distance from the wireless device 1. Figure 7 is a flowchart of the distance calculation process according to an embodiment of the present invention.

[0055] The distance calculation process can be executed, for example, at predetermined time intervals or whenever a predetermined condition is met. For example, the distance calculation process of steps S11 to S30 can be set to start once a day at a predetermined time.

[0056] First, information or a signal is transmitted from the wireless device 1 to the wireless tag 2a (step S11). The information or signal transmitted from the wireless device 1 to the wireless tag 2a is not particularly limited. The wireless device 1 clocks the time when the information or signal was transmitted in step S11 and measures the phase at the time of transmission (step S12). The clocked time and the measured phase are then stored in the memory of the control unit 11 (step S13).

[0057] Next, the wireless tag 2a receives the information or signal from the wireless device 1 (step S14). The wireless tag 2a clocks the time when the information or signal was received in step S14 and measures the phase at the time of reception (step S15). The clocked time and the measured phase are then stored in the memory 22 (step S16).

[0058] Next, the wireless tag 2a transmits information or a signal to the wireless device 1 (step S17). There are no particular restrictions on the information or signal transmitted from the wireless tag 2a to the wireless device 1. The wireless tag 2a clocks the time when the information or signal was transmitted in step S17 and measures the phase at the time of transmission (step S18). The clocked time and the measured phase are then stored in the memory 22 (step S19).

[0059] The wireless device 1 receives the information or signal transmitted in step S17 (step S20). The wireless device 1 clocks the time when the information or signal was received in step S20 and measures the phase at the time of reception (step S21). The clocked time and the measured phase are then stored in the memory of the control unit 11 (step S22). When step S22 is completed, the process proceeds to step S23.

[0060] The wireless device 1 transmits to the wireless tag 2a via the RF chip 12 (step S23) the information stored in step S13 regarding the time when the signal was transmitted in step S11 and the phase at the time of transmission, and the information stored in step S22 regarding the time when the signal was received in step S120 and the phase at the time of reception.

[0061] Then, the wireless tag 2a receives information regarding the time and phase at the time of transmission when the wireless device 1 transmitted the information or signal in step S11, and information regarding the time and phase at the time of reception when the wireless device 1 received the information or signal in step S20 (step S24).

[0062] Next, the microprocessor 21 of the wireless tag 2a calculates the phase shift between the phase of the signal generated by the oscillator 13 of the wireless device 1 and the phase of the signal generated by the oscillator 25 of the wireless tag 2a (step S25). The phase shift can be calculated based on the phase difference between the phase of the carrier wave constituting the information or signal transmitted from the wireless device 1 to the wireless tag 2a and the phase of the signal oscillated by the oscillator 25 of the wireless tag 2a when the wireless tag 2a receives the information or signal, and the phase difference between the phase of the carrier wave constituting the information or signal transmitted from the wireless tag 2a to the wireless device 1 and the phase of the signal oscillated by the oscillator 13 of the wireless device 1 when the wireless device 1 receives the information or signal.

[0063] The phase of the carrier wave constituting the information or signal transmitted from the wireless device 1 to the wireless tag 2a is the phase of the information or signal transmitted in step S11. Information regarding this phase is transmitted from the wireless device 1 to the wireless tag 2a in step S23. The phase of the signal oscillated by the oscillator 25 of the wireless tag 2a when the wireless tag 2a receives the information or signal is the phase of the information or signal received in step S14. Information regarding this phase is measured by the wireless tag 2a in step S15 and stored in step S16. The phase of the carrier wave constituting the information or signal transmitted from the wireless tag 2a to the wireless device 1 is, for example, the phase of the information or signal transmitted in step S17. Information regarding this phase is stored by the wireless tag 2a in step S19. The phase of the signal oscillated by the oscillator 13 of the wireless device 1 when the wireless device 1 receives the information or signal is, for example, the phase of the information or signal received in step S20. The information about the phase is measured in step S21 and transmitted from the wireless device 1 to the wireless tag 2a in step S23.

[0064] Here, the phase of the carrier wave constituting the information or signal transmitted from the wireless device 1 to the wireless tag 2a is a concept that includes not only the phase of the carrier wave constituting the information or signal transmitted from the wireless device 1 to the wireless tag 2a, but also the phase of the carrier wave constituting the signal obtained by mixing down this information or signal.Similarly, the phase of the carrier wave constituting the information or signal transmitted from the wireless tag 2a to the wireless device 1 is a concept that includes not only the phase of the carrier wave constituting the information or signal transmitted from the wireless tag 2a to the wireless device 1, but also the phase of the carrier wave constituting the signal obtained by mixing down this information or signal.

[0065] The phase difference between the phase of the carrier wave constituting the information or signal transmitted from the wireless device 1 to the wireless tag 2a and the phase of the signal oscillated by the oscillator 25 of the wireless tag 2a when the information or signal is received by the wireless tag 2a is defined as ΔΦ Ｓ and the phase difference between the phase of the carrier wave constituting the information or signal transmitted from the wireless tag 2a to the wireless device 1 and the phase of the signal oscillated by the oscillator 13 of the wireless device 1 when the information or signal is received by the wireless device 1 is defined as ΔΦ Ｍ Then, the phase difference ΔΦ Ｓ and phase difference ΔΦ Ｍ From the arithmetic mean of these, the phase difference ΔΦ caused by the signal propagating between the wireless device 1 and the wireless tag 2a is Ｐ That is, it is possible to calculate ΔΦ using the formula (1): Ｐ = 1 / 2 × (ΔΦ Ｓ +ΔΦ Ｍ ) and the phase difference ΔΦ Ｐ can be calculated.

[0066] The phase difference between the wireless device 1 and the wireless tag 2a is ΔΦ Ｃ Then, the equation (2): ΔΦ Ｍ =ΔΦ Ｐ + (-ΔΦ Ｃ ) holds, so the phase shift ΔΦ Ｃ is the phase difference ΔΦ Ｐ from the phase difference ΔΦ Ｍ That is, it can be calculated by subtracting ΔΦ Ｃ = 1 / 2 × (ΔΦ Ｓ -ΔΦ Ｍ) causes a phase shift ΔΦ Ｃ In step S25, the phase shift between the wireless device 1 and the wireless tag 2a is calculated using equation (3).

[0067] Here, the phase shift ΔΦ Ｃ was calculated using equation (3), but the phase shift ΔΦ Ｃ However, it may be further subtracted by 2π or 4π, i.e., 2nπ. n can be 0 or a positive integer. Therefore, the propagation time T Ｐ Based on the time difference between the wireless device 1 and the wireless tag 2a, it is possible to determine whether n is 0, 1, or 2 (i.e., the phase difference ΔΦ obtained from equation (3)). Ｃ It is also possible to determine whether the value obtained by further subtracting 2nπ from the phase shift is the original phase shift, or whether the value without the subtraction is the original phase shift.

[0068] The signal transmitted from the wireless device 1 to the wireless tag 2a and the signal transmitted from the wireless tag 2a to the wireless device 1 may start with an output of an arbitrary value rather than 0 at the start of transmission. In such a case, the phase at the start of transmission and the transmission time are measured, and the phase shift ΔΦ Ｃ It is necessary to correct ΔΦ by always keeping the phase constant at the start of transmission and transmitting at a predetermined time, and then measuring the phase at the start of transmission and the transmission time. Ｃ This makes it possible to omit processing such as correcting the

[0069] In the wireless tag 2a, the calculated phase shift ΔΦ Ｃ Based on this, the phase of the signal generated by the oscillator 25 of the wireless tag 2a is corrected so as to synchronize with the signal generated by the oscillator 13 of the wireless device 1 (step S26). The phase correction in step S26 is controlled and executed by the microprocessor 21. The phase shift of the oscillator 25 of the wireless tag 2a occurs due to the influence of the environment surrounding the wireless tag 2a. By periodically performing synchronization processing in this manner, the clock 24a of the wireless tag 2a can be made to keep time with high accuracy.

[0070] Next, the wireless device 1 calculates the time difference between the wireless device 1 and the wireless tag 2a based on the time when the wireless device 1 transmitted information or a signal to the wireless tag 2a, the time when the wireless tag 2a transmitted information or a signal to the wireless device 1, the time when the wireless tag 2a received the information or signal transmitted from the wireless device 1 and clocked it, and the time when the wireless tag 2a received the information or signal transmitted from the wireless device 1 and clocked it (step S27).

[0071] The time when the information or signal is transmitted from the wireless device 1 to the wireless tag 2a is the time when the information is transmitted in step S11. Information about the time is transmitted from the wireless device 1 to the wireless tag 2a in step S23. The time when the information or signal is transmitted from the wireless tag 2a to the wireless device 1 is the time when the information or signal is transmitted in step S17. The information about the time is stored by the wireless tag 2a in step S19. Next, the time when the information or signal is transmitted from the wireless device 1 and received and clocked by the wireless tag 2a is the time when the information is received in step S14. The information about the time is clocked by the wireless tag 2a in step S15 and stored in step S16. The time when the information or signal is transmitted from the wireless tag 2a and received and clocked by the wireless device 1 is the time when the information or signal is received in step S20. The information about the time is clocked in step S21 and transmitted from the wireless device 1 to the wireless tag 2a in step S23.

[0072] The time when the information or signal is transmitted from the wireless device 1 to the wireless tag 2a is T Ｍ and the time when the information or signal is transmitted from the wireless tag 2a to the wireless device 1 is defined as T Ｓ and the time when the wireless tag 2a receives the information or signal transmitted from the wireless device 1 and clocks it is defined as T ＭＳ Furthermore, the time when the information or signal is transmitted from the wireless tag 2a and received by the wireless device 1 is defined as T ＳＭ Then, the time difference between the wireless device 1 and the wireless tag 2a is expressed by the following equation (4): T Ｌ = 1 / 2 × ((T ＳＭ -T Ｓ )-(T ＭＳ -T Ｍ)) In step S27, the time difference between the wireless device 1 and the wireless tag 2a is calculated using equation (4). Based on the calculated time difference, the wireless tag 2a corrects the time on its own so as to synchronize with the time on the wireless device 1 (step S28).

[0073] Next, the distance between the wireless device 1 and the wireless tag 2a is calculated (step S29). In step S29, the distance between the wireless device 1 and the wireless tag 2a can be calculated by calculating the propagation time of the information or signal between the wireless device 1 and the wireless tag 2a from the substantial difference between the time when the wireless device 1 transmits the information or signal and the time when the wireless tag 2a receives the information or signal, and multiplying the propagation time by the propagation speed of the information or signal (for example, the speed of light). The difference between the time when the information or signal is transmitted by the wireless device 1 and the time when the information or signal is received by the wireless tag 2a can be calculated, for example, based on the time when the information or signal is transmitted from the wireless device 1 to the wireless tag 2a in step S11 (the time when the information or signal is transmitted from the wireless device 1 to the wireless tag 2a in step S23) and the time when the information or signal is received from the wireless device 1 at the wireless tag 2a in step S14, which is the time stored in memory 22 in step S16, and the time difference calculated in step S27.

[0074] Furthermore, in step S29, the distance between the wireless device 1 and the wireless tag 2a can be calculated by calculating the propagation time of the information or signal between the wireless device 1 and the wireless tag 2a from the substantial difference between the time when the wireless tag 2a transmits the information or signal and the time when the wireless device 1 receives the information or signal, and multiplying the propagation time by the propagation speed of the information or signal (e.g., the speed of light). The difference between the time when the wireless tag 2a transmits the information or signal and the time when the wireless device 1 receives the information or signal can be calculated, for example, based on the time when the wireless tag 2a transmits the information or signal to the wireless device 1 in step S17, which is stored in the memory 22 in step S19, and the time when the wireless device 1 receives the information or signal in step S20 (transmitted from the wireless device 1 to the wireless tag 2a in step S23), and the time difference calculated in step S27.

[0075] The distance between the wireless device 1 and the wireless tag 2a calculated in step S29 is stored in the memory 22 of the wireless tag 2a in association with, for example, time information about the calculated time and identification information (or location information of the wireless device 1) that can identify the wireless device 1 (step S30). By executing step S30, the distance calculation process is completed.

[0076] By executing the processes of steps S11 to S30, it is possible not only to correct the time difference and phase difference between the wireless device 1 and the wireless tag 2a, but also to calculate the distance between the wireless device 1 and the wireless tag 2a. Note that although the time difference between the wireless device 1 and the wireless tag 2a is corrected in step S28, it is not necessary to correct the time difference, and it is also possible to calculate the distance between the wireless device 1 and the wireless tag 2a without correcting the time difference based on the time difference calculated in step S27. Also, although the phase difference between the wireless device 1 and the wireless tag 2a is corrected in step S26, it is not necessary to correct the phase difference, and it is also possible to calculate the distance between the wireless device 1 and the wireless tag 2a without correcting the phase difference.

[0077] Furthermore, by executing the processing from steps S11 to S30, the time difference and phase difference between the wireless device 1 and the wireless tag 2a are corrected and the distance between the wireless device 1 and the wireless tag 2a is calculated, but it is also possible to execute the processing for correcting the time difference between the wireless device 1 and the wireless tag 2a, the processing for correcting the phase difference between the wireless device 1 and the wireless tag 2a, and the processing for calculating the distance between the wireless device 1 and the wireless tag 2a separately.

[0078] The above-described process for calculating the distance between the wireless device 1 and the wireless tag 2a can calculate the distance between one wireless tag 2a and each of multiple wireless devices 1. When specifying the position of the wireless tag 2a, as will be described later, the distance between the wireless device 1 and the wireless tag 2a is specified for as many wireless devices 1 as necessary to specify the position. However, even when calculating the distance between one wireless tag 2a and each of multiple wireless devices 1, the time shift correction process and the phase shift correction process can be performed only with one wireless device 1, and the time shift correction process and the phase shift correction process can be omitted when communicating with other wireless devices 1.

[0079] Here, the distance between the wireless device 1 and the wireless tag 2a is calculated in the wireless tag 2a, but the distance between the wireless device 1 and the wireless tag 2a may be calculated in the wireless device 1 by processing similar to step S29 instead of the wireless tag 2a. When the distance is calculated in the wireless device 1, the distance between the wireless device 1 and the wireless tag 2a is stored in the memory of the control unit 11 in association with time information regarding the calculated time, etc., and identification information that can identify the wireless tag 2a.

[0080] Alternatively, instead of using the wireless tag 2a, the server device 3 may calculate the distance between the wireless device 1 and the wireless tag 2a by processing similar to that of step S29. When the server device 3 calculates the distance, the information necessary for the calculation is received directly or indirectly from the wireless device 1 and / or the wireless tag 2a. When the server device 3 calculates the distance, the distance between the wireless device 1 and the wireless tag 2a is stored in the storage unit 33 of the server device 3 in association with time information regarding the calculated time, etc., identification information capable of identifying the wireless device 1 (or location information of the wireless device 1), and identification information capable of identifying the wireless tag 2a.

[0081] Although the distance between the wireless device 1 and the wireless tag 2a is calculated here, if there are multiple wireless tags 2a, the distance between one wireless tag 2a and another wireless tag 2a can be calculated. In this case, the propagation time for the information or signal to propagate between one wireless tag 2a and another wireless tag 2a can be calculated from the substantial difference between the time when the information or signal is transmitted by one wireless tag 2a and the time when the information or signal is received by another wireless tag 2a, and the propagation time can be multiplied by the propagation speed of the information or signal (for example, the speed of light) to calculate the distance between the one wireless tag 2a and another wireless tag 2a.

[0082] [Position Identification Process] Next, the position identification process according to the embodiment of the present invention will be described. Identifying the position of a wireless tag 2a is premised on the fact that the distances between the wireless tag 2a and each of the multiple wireless devices 1 have been calculated in the distance calculation process. For example, if one wireless tag 2a and multiple wireless devices 1 are located at the same height, i.e., if these devices exist on the same XY plane, the position of the wireless tag 2a (e.g., the XY coordinates of the wireless tag 2a) can be identified based on the distances between the wireless tag 2a and each of the three wireless devices 1 and the positions of the three wireless devices 1. Therefore, if one wireless tag 2a and multiple wireless devices 1 are located at the same height, the number of distance data between the wireless device 1 and the wireless tag 2a required to identify the position is three.

[0083] Furthermore, for example, if one wireless tag 2a and at least one of the multiple wireless devices 1 are at different heights and are not on the same plane, the position of the wireless tag 2a (for example, the XYZ coordinates or latitude and longitude of the wireless tag 2a) can be identified based on the distances between the one wireless tag 2a and four wireless devices 1 and the positions of the four wireless devices 1. Therefore, if one wireless tag 2a and at least one of the multiple wireless devices 1 are at different heights and are not on the same plane, the number of pieces of distance data between the wireless device 1 and the wireless tag 2a required to identify the position is four.

[0084] In the system 10, items equipped with wireless tags 2a are placed on shelves of different heights and are moved by users, so the number of pieces of distance data between the wireless device 1 and the wireless tag 2a required to identify the location is usually four.

[0085] 8 is a diagram showing a flowchart of a location identification process according to an embodiment of the present invention. The location identification process shown in FIG. 8 can be executed by, for example, the wireless device 1, the wireless tag 2a, or the server device 3. When the location identification process is executed by the wireless device 1, information on the distance between each of the multiple wireless devices 1 and the wireless tag 2a (the distance calculated in step S29) is associated with time information on the calculated time, identification information of the wireless device 1 (or location information of the wireless device 1), and identification information of the wireless tag 2a, and is transmitted to the wireless device 1 or the server device 3 for use. The following describes the case where the location identification process is executed by the wireless tag 2a.

[0086] In the position identification process, the position of the wireless tag 2a is identified (step S31) based on the distance between each of the multiple wireless devices 1 and the wireless tag 2a and the positions of these wireless devices 1. The positions of the wireless devices may be stored in advance in the memory 22 of the wireless tag 2a that executes the position identification process. The calculation process for identifying the position of the wireless tag 2a is not particularly limited.

[0087] The identified position of the wireless tag 2a is stored in the memory 22 of the wireless tag 2a in association with time information on the calculated time (time information on the time when the distance was calculated or time information on the time when the position was identified), the identification information of the wireless device 1 (or the position information of the wireless device 1), and the identification information of the wireless tag 2a (step S32). Steps S31 and S32 complete the position identification process.

[0088] It is preferable that the distances between the wireless tag and each of the multiple wireless devices 1, which are used to identify the location of the wireless tag 2a in step S31, are calculated at the same time or close to each other (for example, calculated when the propagation times of information or signals between each of the multiple wireless devices and the wireless tag are measured at the same time or close to each other). Here, close times are not particularly limited, but are preferably times within a predetermined range from time 1. By using the distances between the wireless tag and each of the multiple wireless devices 1 calculated at the same time or close to each other, it is possible to identify the location at that time more accurately.

[0089] Here, the distance between each of the multiple wireless devices 1 and the wireless tag 2a is calculated, and the position of the wireless tag 2a is identified based on the calculated distance. However, if there are multiple wireless tags 2a, the distance between the one wireless tag 2a and each of the multiple other wireless tags 2a can be calculated, and the position of the one wireless tag 2a can be identified based on the calculated distance.

[0090] [Product Order Identification Processing] In the system 10, the location information of the wireless tags 2a can also be used for other data collection and analysis. By identifying the order in which a group of products that a customer has paid for at the same time at the checkout terminal 5 were moved to the customer's basket (cart), it becomes possible to understand the order in which customers pick up products in a retail store. Analyzing such order-related data can be used as a reference when considering product placement in a retail store and the layout of product shelves in a store.

[0091] FIG. 9 is a flowchart illustrating a product order determination process according to an embodiment of the present invention. FIG. 10 is a diagram illustrating a location management table according to an embodiment of the present invention. First, the server device 3 determines the time when the location of each product in the group of products simultaneously read by the reading device 4 changed (step S41). The time when the location of each product changed can be determined based on the location management table 50 of the server device 3. For example, the storage unit 33 of the server device 3 stores the location management table 50 shown in FIG. 10 . The location management table 50 associates location information 52 of the wireless tag 2 a with time 51. In FIG. 10 , if the location (coordinates) at 12:00 and 12:01 are the same, but the location (coordinates) at 12:01 and 12:02 are different, then 12:01 can be estimated as the time when the location of the wireless tag 2 a changed.

[0092] In step S41, "simultaneously read by the reader 4" does not necessarily mean that the items were read at the same time. For example, the checkout terminal 5 can send identification information (a transaction ID) that can identify a transaction for each payment transaction to the server device 3, and multiple items associated with the same transaction ID can be considered to have been simultaneously read by the reader 4, thereby identifying the time when the position changed.

[0093] Next, the server device 3 generates data that lists the product types in order of the time when the identified location changes occurred, and outputs this data (steps S42 and S43). In step S42, the time order may be ascending or descending. Furthermore, if a single transaction ID contains data with different dates, data is generated that lists the data in ascending or descending order, including the date and time.

[0094] In step S43, "outputting data" refers to printing the generated data on a receipt or displaying it on a computer screen. Next, the server device 3 stores the product type and the time of the location change in association with the transaction ID in the storage unit 33 (step S44). In step S44, the stored data may be the same as the output data, or it may be data that enables the output data to be reproduced, storing the product type, the time of the location change, and optionally the order in association with the transaction ID.

[0095] Store managers and others can compare the purchase order of a specific product across multiple transaction IDs based on the data stored in the server device 3. This can be used as reference data when changing or deciding on the product sales area or layout in a store, such as moving a product that is moved immediately before payment processing to a sales area near the transaction terminal 5.

[0096] According to a first effect of the present invention, it is possible to provide a wireless tag that can calculate the distance between the wireless tag and a wireless device and read information about an item. If the distance between the wireless tag and the wireless device changes, it is possible to know that the position of the wireless tag or the item has changed. According to a second effect of the present invention, it is possible to provide a method for calculating the distance between the wireless tag and a wireless device. If the distance between the wireless tag and the wireless device changes, it is possible to know that the position of the wireless tag or the item has changed.

[0097] REFERENCE SIGNS LIST 1 Wireless device, 2 Merchandise, 2a Wireless tag, 3 Server device, 4 Reading device, 5 Accounting terminal, 6 Communication network, 11 Control unit, 12 RF chip, 12a Clock, 12b Phase detector, 13 Oscillator, 21 Microprocessor, 22 Memory, 23 Antenna, 24 RF chip, 24a Clock, 24b Phase detector, 25 Oscillator, 26 Battery 31 Control unit, 32 RAM, 33 Storage unit, 34 Communication interface

Claims

1. A radio tag that is attached to an item, has a clock, calculates the distance to the radio device based on the information or signal propagation time between the radio device and the tag, and can read information about the item using a reader.

2. The wireless tag according to claim 1, which calculates the distance to each of multiple wireless devices based on the propagation time of information or signals from each of multiple wireless devices, and identifies the location of the wireless tag or article based on the calculated distance to each of the multiple wireless devices.

3. The wireless tag according to claim 1 or 2, which performs a predetermined function using power obtained from electromagnetic waves received from a wireless device and / or a reader.

4. The wireless tag according to claim 1 or 2, further comprising a battery, the battery supplying power to the clock.

5. A radio tag as claimed in claim 1 or 2, which calculates the time difference between the radio device and the radio tag by communicating between them, and corrects the time on the clock based on the calculated time difference.

6. A radio tag according to claim 1 or 2, which calculates the phase difference between the clocks of the radio device and the radio tag by communicating between the radio device and the radio tag, and corrects the phase in the radio tag based on the calculated phase difference.

7. An article to which the wireless tag according to claim 1 or 2 is attached.

8. A method for calculating the distance between a radio tag equipped with a clock and a radio device based on the propagation time of information or signals between the radio tag and the radio device.

9. The method according to claim 8, wherein the distance between each of the plurality of wireless devices and the wireless tag is calculated based on the information or signal propagation time between each of the plurality of wireless devices and the wireless tag, and the position of the wireless tag is identified based on the calculated distance between each of the plurality of wireless devices and the wireless tag.

10. The method according to claim 8 or 9, wherein a radio tag is attached to the item, and a reader reads information about the item stored in the radio tag.

11. The method according to claim 10, wherein when the wireless tag is located within a predetermined area, a reader reads the information about the item stored in the wireless tag.

12. The method according to claim 10, wherein the article is a product, the reading device reads information about the product stored in the wireless tag, and the computer device outputs the price of the product based on the read information about the product.

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