Trigger threshold modification for radio frequency identification devices in electronic article surveillance systems

Abstract

An electronic monitoring item system is provided that reduces the number and likelihood of false alarms. Such a system includes two read zones, with the second read zone having an associated RFID (radio frequency identification) reader configured to detect an RFID device at a trigger threshold. The trigger threshold can be set or modified in view of a value of a sensor (sensing, for example, capacitance or dielectric constant or temperature or degree of movement) of the RFID device, a number of times the RFID device is detected in the first read zone, or whether the RFID device is detected in the first read zone under a predetermined condition. Such a system can also or alternatively initiate a response (e.g., modify the trigger threshold or amount of power transmitted by the RFID reader) when an RFID protection device associated with infrastructure in the first read zone is detected in the second read zone.

Description

[0001] Cross-referencing of related patent applications

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 62 / 970,933, filed February 6, 2020, which is incorporated herein by reference in its entirety. Technical Field

[0003] This invention relates to radio frequency identification (RFID) devices. More specifically, it relates to controlling the trigger thresholds of RFID devices used in electronic article surveillance (EAS) systems. Background Technology

[0004] In retail stores, accurate counting of displayed and / or in-stock products is crucial. Additionally, having an effective anti-theft system in appropriate locations is essential. RFID tags and markings (collectively referred to herein as "RFID devices") have been employed to perform both of these functions.

[0005] An EAS system employing RFID technology typically has two main reading zones, each containing associated RFID readers. One reading zone is the store area where products are presented to consumers (which may be referred to herein as the "inventory zone"), while the other reading zone is the store exit area where any RFID devices that have not been properly deactivated can be detected to trigger some type of alarm indicating that someone is attempting to steal the product (which may be referred to herein as the "detection zone"). Typically, when a customer correctly purchases an item, the cashier removes or deactivates the RFID device associated with that item. If the RFID device is not removed or deactivated, one or more RFID readers will read the device and trigger an alarm or other alert in the detection zone.

[0006] While the aforementioned systems are common, they have certain drawbacks. A common problem when using RFID devices / systems in EAS systems is that the reading range of an RFID device may be large enough in certain situations that an RFID device in the inventory area can be read in the detection area, or vice versa. To mitigate this risk, a transition zone is often provided between the inventory and detection areas to physically separate the two reading zones. However, because different RFID devices have varying sensitivities at different operating frequencies and / or different items have different effects on the performance of associated RFID devices, it is necessary to make the transition zone relatively large. A larger transition zone implies a smaller inventory area, meaning less physical space for retailers to present goods to consumers and thus lost sales (revenue).

[0007] An inventory management / EAS system is required, where the inventory area is maximized while the transition area is reduced or minimized, but it remains effective in detecting theft and reducing or minimizing false alarms.

[0008] Therefore, it would be advantageous to provide an EAS system configured in a way that allows for a reduction in the size of the transition zone and / or a decrease in the occurrence of false alarms. Summary of the Invention

[0009] Several aspects of the subject matter of this invention can be implemented individually or together in the apparatus, systems, and methods described and claimed below. These aspects can be used alone or in combination with other aspects of the subject matter described herein, and the common description of these aspects is not intended to exclude their use alone or in different combinations that may be elucidated in the appended claims.

[0010] In one aspect, an electronic article monitoring system includes a first reading area with associated RFID readers and a second reading area with associated RFID readers, the RFID readers being configured to detect RFID devices at a trigger threshold. The system further includes a controller configured to set the trigger threshold based at least in part on factors selected from the group consisting of: the value of the RFID device's sensor, the number of times an RFID device is detected in the first reading area, and whether an RFID device is detected in the first reading area under predetermined conditions.

[0011] In another aspect, a method for controlling an electronic article surveillance system is provided, the electronic article surveillance system having a first reading area and a second reading area, wherein an RFID device is detected in the second reading area at a trigger threshold. The method includes setting the trigger threshold based at least in part on factors selected from the group consisting of: the value of the RFID device's sensor, the number of times the RFID device is detected in the first reading area, whether the RFID device is detected in the first reading area under predetermined conditions, and combinations thereof.

[0012] On the other hand, an electronic article surveillance system includes a first reading zone comprising an associated RFID reader, wherein infrastructure is at least partially located within the first reading zone. An RFID protection device is fixed relative to the infrastructure. A second reading zone of the system includes an associated RFID reader configured to detect an RFID inventory device associated with inventory, which is removably associated with the infrastructure, upon triggering a threshold. The system also includes a controller configured to initiate a response selected from the group consisting of: modifying the trigger threshold, modifying the electrical force transmitted by the RFID reader associated with the second reading zone, modifying the direction of power transmission by the second RFID reader associated with the second reading zone, and transmitting a signal indicating that the infrastructure needs to be moved away from the second reading zone.

[0013] In another aspect, a method for controlling an electronic article surveillance system is provided, the electronic article surveillance system having a first reading area and a second reading area, wherein infrastructure is at least partially located within the first reading area and has associated RFID protection devices, and wherein an RFID inventory device associated with inventory is detected in the second reading area at a trigger threshold, the inventory being removably associated with the infrastructure. The method includes: when the RFID protection device is detected in the second reading area, initiating a response selected from the group consisting of: modifying the trigger threshold, modifying the electrical power transmitted by the RFID reader associated with the second reading area, modifying the direction of power transmission by the RFID reader associated with the second reading area, and transmitting a signal indicating that the infrastructure needs to be moved away from the second reading area. Attached Figure Description

[0014] Figure 1 This is an illustrative representation of an exemplary embodiment of an electronic article monitoring system according to one aspect of the present invention.

[0015] Figure 2This is an illustrative representation of another exemplary embodiment of an electronic article monitoring system according to one aspect of the present invention. Detailed Implementation

[0016] Detailed embodiments of the invention have been disclosed herein as needed; however, it should be understood that the disclosed embodiments are merely examples of the invention, which can be implemented in various forms. Therefore, the specific details disclosed herein should not be construed as limiting, but merely as a basis for the scope of the invention claims and as a representative basis for teaching those skilled in the art to use the invention differently in virtually any suitable manner.

[0017] Figure 1 An EAS system 10 employing RFID technology according to an aspect of the present invention is shown. Figure 1 The EAS system 10 has a storage area 12 and a detection area 14, wherein a transition area 16 separates the two reading areas 12, 14. The EAS system 10 further includes a controller 18 coupled to a first RFID reader 20 associated with the storage area 12 and a second RFID reader 22 associated with the detection area 14. Multiple inventories 24, 26 are shown positioned within the storage area 12, each inventory 24, 26 having an associated RFID device 28, 30 (which may be referred to herein as an RFID inventory device). Inventories 24, 26 may be configured in different ways, thereby affecting the performance of the associated RFID devices 28, 30 in different ways, as will be described in more detail herein.

[0018] As explained above, inventory area 12 represents the store area where products are presented to consumers, while detection area 14 represents the store exit area where any RFID inventory devices that have not been properly deactivated can be detected to trigger some type of alarm indicating that someone is attempting to steal the product. When a customer correctly purchases an item, the cashier removes or deactivates the RFID inventory device associated with that item. If the RFID inventory device is not removed or deactivated, it will be detected in detection area 14, causing an alarm or other alert to be triggered and notifying store staff.

[0019] Each inventory is 24 and 26. Figure 1 The structures are shown as removably associated with infrastructures 32 and 34, which are configured to support and display one or more associated inventories in inventory area 12. In the illustrated embodiment, one of the infrastructures 32 is configured as a mannequin, while the other infrastructure 34 is configured as a table; however, it should be understood that the infrastructures may be configured in other ways without departing from the scope of the invention. Figure 1In this embodiment, each infrastructure 32, 34 includes an associated RFID device 36, 38 (which may be referred to herein as an RFID protection device), which is fixed relative to the infrastructure 32, 34 (e.g., by attaching to the infrastructure 32, 34). Unlike RFID inventory devices 28, 30, RFID protection devices 36, 38 are not configured to generate an alarm when they are detected in detection zone 14, but can be used to reduce false alarms caused by the detection of RFID inventory devices in detection zone 14, as will be described in more detail.

[0020] Figure 1 The EAS system 10 is shown as including an additional reading area 40 configured to receive inventory before it is moved to inventory area 12. This initial or preliminary reading area 40 is provided to determine the number of existing inventories before they are moved to inventory area 12 for display and customer consideration. The initial or preliminary reading area 40 can be configured in various ways without departing from the scope of the invention. In the illustrated embodiment, the initial or preliminary reading area 40 is configured as an RFID reading room including associated RFID readers 42 and configured to receive multiple inventories and their associated RFID devices. Depending on the store's needs and configuration, the RFID reading room can be relatively large (e.g., configured to accommodate multiple containers loaded on pallets) or small (e.g., configured to accommodate a single container). In other embodiments, the initial or preliminary reading area 40 (if provided) can be configured differently, such as as an RFID-enabled door through which inventory passes before reaching inventory area 12, or as a warehouse or storage area where RFID inventory devices are detected or read by handheld RFID readers operated by store employees.

[0021] It should be understood that Figure 1 The configuration shown is merely exemplary, and the EAS system according to the invention can be configured in different ways without departing from the scope of the invention. For example, although Figure 1 Different RFID readers 20, 22 are shown associated with inventory area 12 and inspection area 14, but a single RFID reader 46 is associated with both areas 12, 14 (as shown in...). Figure 2 The EAS system 10' shown is within the scope of this invention. In some embodiments, the inventory area and / or detection area has multiple readers, for example, two, three, four, five or more. In some embodiments, the multiple readers are controlled by a single controller. In other embodiments, each reader is controlled by its own controller. In other embodiments, the multiple readers are controlled by more than one controller, but the number of controllers is less than the number of readers, such that at least more than one reader is controlled by one controller.

[0022] Regardless of the specific configuration of the EAS system, ideally, the size of the transition zone 16 is determined and configured such that RFID devices (especially RFID inventory devices) located in the inventory zone 12 are detected only by the RFID reader 20 associated with the inventory zone 12, while the RFID reader 22 associated with the detection zone 14 is not detected (or, in Figure 2 In the case of system 10', detection is achieved only by the signal 18 emitted by the RFID reader into the storage area 12, not the detection area 14. Conversely, it is advantageous that RFID devices located in the detection area 14 are detected only in the detection area 14 and not in the storage area 12. This can be achieved by providing a large transition area 16, but this method reduces the size of the storage area 12, so it is not a satisfactory solution.

[0023] According to one aspect of the invention, the size of the transition zone 16 can be reduced by adjusting the level at which RFID inventory devices are detected in the detection zone 14 (which may be referred to herein as the “trigger threshold”). Although this aspect of the invention has been described in relation to adjusting the trigger threshold of the detection zone 14 (to prevent false alarms when RFID inventory devices in the inventory zone 12 are detected in the detection zone 14), it should be understood that the trigger threshold of the inventory zone 12 can be similarly adjusted to prevent the detection zone 14 from being detected in the inventory zone 12.

[0024] Several factors can influence the performance characteristics of an RFID device (and therefore whether such an RFID device is detected in different reading zones), resulting in various conditions that can guarantee the modification of the trigger threshold for a particular RFID device. According to one method, an RFID inventory device may include a sensor that records specific values, which can be transmitted to a controller 18 of the EAS system 10, 10'. Based on the sensor values, the controller 18 can determine whether to adjust the trigger threshold of the RFID inventory device associated with the sensor. This adjustment may include decreasing the trigger threshold (e.g., if the value indicates a risk of theft of inventory associated with the RFID inventory device) or increasing the trigger threshold (e.g., if the value indicates no risk of theft of inventory associated with the RFID inventory device). Each RFID inventory device can be programmed with a unique identifier to allow the controller 18 to assign an appropriate trigger threshold to the appropriate RFID inventory device.

[0025] The sensor can be configured in various ways without departing from the scope of the invention. In one exemplary embodiment, the sensor value is capacitance. Such a sensor can be particularly used in self-tuning RFID devices configured to change their capacitance to optimize the performance of the RFID device. For example, when the self-tuning RFID device is associated with a low-loss material (e.g., a T-shirt or other light clothing), the RFID device will tend to self-tune to a relatively high capacitance to reduce the performance peak to the desired RFID reader operating range. In contrast, when the self-tuning RFID device is associated with or placed near a high-loss material (e.g., an item with high moisture content, such as the human body), the RFID device will tend to self-tune to a relatively low capacitance to improve the performance peak. A relatively high capacitance will require adjustment of the trigger threshold in one direction, while a relatively low capacitance will require adjustment of the trigger threshold in the opposite direction. It is also possible that the sensed capacitance is at a level where no adjustment of the trigger threshold is required.

[0026] In yet another exemplary embodiment, the sensor can be configured as a dielectric sensor, in which case the sensor value is the dielectric constant. Such a sensor can be advantageous when the RFID device is not self-tunable and instead has performance affected only by external factors (e.g., the nature of associated inventory). In one example, the dielectric load can be determined by measuring values ​​associated with the RFID device, such as received signal strength, as the RFID reader changes frequency. When the RFID device is associated with a light dielectric, read performance tends to increase with increasing read frequency, but read performance tends to decrease with increasing read frequency of an RFID device associated with a heavy dielectric. When the sensor value indicates that the RFID device is associated with a light dielectric, the trigger threshold can be increased to prevent false alarms (without increasing the risk of failing to detect the RFID device correctly). Conversely, when the sensor value indicates that the RFID device is associated with a heavy dielectric, the RFID device will have lower performance, in which case the trigger threshold can be decreased to allow correct detection of the RFID device without increasing the risk of false alarms. It is also possible that the sensed dielectric constant is at a level where no adjustment to the trigger threshold is required.

[0027] In another exemplary embodiment, the sensed value could be temperature. When goods are stolen, they are typically kept close to people, which tends to increase the sensed temperature. Therefore, an increase in the temperature of the RFID inventory device indicates an increased risk that someone is attempting to steal the associated goods. In this case, the controller 18 can take action to reduce the trigger threshold to better ensure that the RFID inventory device is correctly detected when it moves into the detection zone 14 without being deactivated.

[0028] In yet another exemplary embodiment, the sensed value is the degree of movement. Products being stolen will move towards the store exit (and towards detection zone 14), while products displayed in inventory zone 12 may be stationary. Therefore, an increase in the degree of movement experienced by the RFID inventory device indicates an increased risk that someone is attempting to steal the associated merchandise. In this case, controller 18 can take action to reduce the trigger threshold to better ensure that the RFID inventory device is correctly detected when it moves into detection zone 14 without being deactivated. An exemplary motion detector may be a moving object (such as a beam of light or a baffle) that changes the value of the RFID device (such as the voltage at the port of the RFID chip), or a similar device that adjusts the input impedance of the RFID chip and thus modulates its response. Materials such as piezoelectric plastics, resistive materials that change when stretched or compressed, or parallel-plate capacitors whose plate separation is affected by movement can also be used.

[0029] However, while reducing the trigger threshold upon sensing movement may generally be appropriate, this is not always the case. For example, it may be that when EAS systems 10, 10' are active, a particular RFID device is associated with inventory intended for replenishing merchandise stock in inventory area 12. This may be true for RFID inventory devices that have recently been detected or read in initial or preliminary reading area 40, since such RFID inventory devices have not yet been moved to inventory area 12 for display and for customers to consider associated merchandise. For a defined period of time (e.g., between 15 and 60 minutes), the trigger threshold for such RFID inventory devices can be set to a maximum (or at least elevated) level, because movement of such RFID inventory devices does not indicate that associated merchandise may be stolen, but rather that merchandise has been moved to inventory area 12. After said time has elapsed, controller 18 can process the RFID inventory device as described above, which may include subsequently moving the RFID inventory device, thereby causing controller 18 to reduce the trigger threshold to better prevent theft of merchandise associated with the RFID inventory device.

[0030] According to another aspect of the invention, the trigger threshold can be adjusted based on the performance of the RFID inventory devices in the initial or preliminary reading zone 40. For example, if the initial or preliminary reading zone 40 is configured as an RFID reading chamber, each RFID device will be read or detected a certain number of times (because the RFID reading chamber includes multiple antennas configured to transmit signals within the RFID reading chamber), which can vary based on several factors, including the nature of the associated inventory. The number of times the RFID inventory devices are read can be encoded in the RFID devices or stored in a database accessible to the controller 18 of the EAS systems 10, 10'. The controller 18 can adjust the trigger threshold of the RFID inventory devices based on the number of times a particular RFID inventory device is read in the RFID reading chamber. A low number of reads may indicate that the RFID device is associated with a product that is difficult to read (e.g., goods with high moisture content), while a high number of reads may indicate that the RFID device is associated with a product that is easy to read (e.g., lightweight clothing). For RFID inventory devices with a low number of reads, the trigger threshold can be reduced to better ensure correct reading of the RFID inventory devices (without increasing the risk of false alarms). For RFID inventory devices with a high number of reads, the trigger threshold can be increased to reduce the risk of false alarms without increasing the risk of failing to read or detect the RFID inventory device correctly.

[0031] According to another aspect of the invention, when the controller 18 determines that an RFID inventory device has been detected by an RFID reader associated with the reading area where the RFID inventory device is located under predetermined conditions, the trigger threshold can be adjusted. For example, an RFID inventory device can be read or detected in the inventory area 12 when there is no person (or at least no customer) in the inventory area 12 (e.g., as determined by a camera or other means associated with the controller 18), or when no RFID inventory device is moving between the inventory area 12 and the detection area 14. RFID inventory devices detected in the inventory area 12 under these conditions can be considered as items with a lower risk of theft (compared to RFID inventory devices detected in the inventory area 12 when a customer is present). The controller 18 can increase the trigger threshold for such RFID inventory devices to better ensure that such RFID inventory devices do not generate false alarms. When a customer enters the inventory area 12, the controller 18 can decrease the trigger threshold for RFID inventory devices in the inventory area 12 because the risk of theft increases.

[0032] In some embodiments, the trigger threshold can be adjusted using any combination of capacitance, dielectric constant, temperature, and mobility.

[0033] While the foregoing discussion pertains to RFID inventory devices, it should be understood that the detection of an RFID protection device in detection zone 14 can trigger a response or change in the operation of the EAS system. As described above, RFID protection devices 36, 38 are designed to be located and maintained within inventory zone 12 and associated with infrastructure 32, 34 used to display and / or support one or more inventories 24, 26. Therefore, if an RFID protection device is detected in detection zone 14, this could indicate an attempt to steal the associated infrastructure (and possibly any inventory associated with it), or indicate that the infrastructure is placed too close to detection zone 14, which could lead to a false alarm caused by the RFID inventory device associated with the inventory corresponding to the infrastructure.

[0034] Regardless of whether an RFID protection device is detected in detection zone 14, system controller 18 can initiate any of a plurality of responses to prevent or reduce the likelihood of false alarms. For example, one possible response is that controller 18 modifies the trigger threshold of one or more RFID inventory devices associated with inventory linked to infrastructure corresponding to the RFID protection device (e.g., adjusting the trigger threshold of an RFID device attached to a shirt worn by a mannequin in inventory zone 12). This could include increasing the trigger threshold to reduce false alarms. Another possible response is to modify the electrical force transmitted by the RFID reader associated with detection zone 14 and / or (if the antenna of the RFID reader is steerable) modify the direction in which the RFID reader transmits power to avoid detecting the RFID protection device. Yet another possible response is that controller 18 transmits a signal indicating that store employees need to move the infrastructure (or merchandise associated with the infrastructure) linked to the RFID protection device away from detection zone 14. In an exemplary embodiment, the signal may be transmitted via the company network or via lights or other indicators associated with the infrastructure to indicate the need to move the infrastructure or associated merchandise to reduce the risk of false alarms.

[0035] RFID protection devices can have different sensitivity levels; for example, "A" can be high sensitivity, and the risk of overreading is relatively low if such an RFID protection device is detected in detection zone 14. "B" type can have relatively low sensitivity, and if detected in detection zone 14, it indicates a very high probability of overreading. In this case, the response initiated by controller 18 may differ from the response initiated when an "A" type RFID protection device is detected. To prevent problems, the trigger threshold of the components configured to detect RFID protection devices in EAS systems 10, 10' can be increased.

[0036] In alternative formats, an RFID protection device can have more than one identifier associated with it. In its most basic form, the RFID device comprises an RFID chip coupled to an antenna. To provide multiple identifiers for the RFID protection device, multiple different RFID chips can be coupled to a common antenna, with each RFID chip having a different sensitivity (e.g., a type "A" RFID chip with high sensitivity, a type "B" RFID chip with low sensitivity, and a type "C" RFID chip with even lower sensitivity). By determining which one or more chips are being detected in detection zone 14, the system controller 18 can determine the risk of false alarms and take various actions based on the sensitivity of the detected one or more chips.

[0037] It should be understood that the above embodiments illustrate some applications of the principles of the subject matter of this invention. Those skilled in the art can make numerous modifications without departing from the spirit and scope of the claimed subject matter, including those combinations of features individually disclosed or claimed herein. For these reasons, the scope of this invention is not limited to the above description, but rather as set forth in the following claims, and it should be understood that the claims can be directed to its features, including combinations of features individually disclosed or claimed herein.

Claims

1. An electronic article monitoring system, comprising: A first reading area, the first reading area including an associated first radio frequency identification (RFID) reader; A second reading area, the second reading area including an associated second radio frequency identification (RFID) reader, the second RFID reader being configured to detect an RFID device at a trigger threshold; The trigger threshold represents the level at which an RFID device in the first reading area can be detected in the second reading area; as well as A controller, associated with the first and second RFID readers, wherein the controller is configured to set the trigger threshold based at least in part on factors selected from the group consisting of: the sensor value of the RFID device, the number of times the RFID device is detected in the first reading area, whether the RFID device is detected in the first reading area under predetermined conditions, and combinations thereof. The controller is configured to decrease the trigger threshold when the RFID device is detected less than a certain number of times in the first reading area, and to increase the trigger threshold when the RFID device is detected more than a certain number of times in the first reading area. The predetermined condition is that there is no person in the first reading area or the RFID device does not move between the first reading area and the second reading area. The first reading area includes an inventory area, and the second reading area includes a detection area, wherein the detection area is separated from the inventory area by a transition area. The controller is configured to increase the trigger threshold when no one is in the inventory area or when no RFID device moves between the inventory area and the detection area, and to decrease the trigger threshold when a customer enters the inventory area.

2. The electronic article monitoring system according to claim 1, further comprising a storage area, wherein, The first reading area is configured to receive the RFID device before the RFID device receives the data in the storage area.

3. The electronic article monitoring system according to claim 2, wherein, The number of times the RFID device is detected in the first reading area is encoded into the RFID device.

4. The electronic article monitoring system according to claim 3, wherein, The number of times an RFID device is detected in the first reading area is stored in a database accessible to the controller.

5. The electronic article surveillance system according to any one of claims 1 to 4, wherein, Different RFID readers are associated with the first reading area and the second reading area.

6. A method for controlling an electronic article surveillance system, the electronic article surveillance system comprising: A first radio frequency identification (RFID) reader, the first radio frequency identification (RFID) reader being associated with a first reading area; A second radio frequency identification (RFID) reader, which is associated with a second reading area; A controller, associated with the first and second RFID readers, wherein the controller is configured to set the trigger threshold based at least in part on factors selected from the group consisting of: the sensor value of the RFID device, the number of times the RFID device is detected in the first reading area, whether the RFID device is detected in the first reading area under predetermined conditions, and combinations thereof. in, An RFID device is detected in the second reading area at a trigger threshold, the trigger threshold representing the level at which an RFID device in the first reading area can be detected in the second reading area; The method includes setting the trigger threshold based at least in part on factors selected from the group consisting of: the number of times the RFID device is detected in the first readout area, and whether the RFID device is detected in the first readout area under predetermined conditions. The predetermined condition is selected from the condition that no one is in the first reading area, or that the RFID device does not move between the first reading area and the second reading area. If the RFID device is detected less than a certain number of times in the first reading area, the trigger threshold is reduced. If the RFID device is detected more than a certain number of times in the first reading area, the trigger threshold is increased; The predetermined condition is that there is no person in the first reading area, or the RFID device does not move between the first reading area and the second reading area. The first reading area includes a storage area, and the second reading area includes a detection area, which is separated from the storage area by a transition area. The controller is configured to increase the trigger threshold when no one is in the inventory area or when no RFID device moves between the inventory area and the detection area, and to decrease the trigger threshold when a customer enters the inventory area.

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