ELECTRONIC SHELF LABEL SYSTEM WITH SHELF RAIL SUBSYSTEM

Description

Technical field

[0001] The invention relates to an electronic shelf label system with a shelf rail subsystem. Background.

[0002] An electronic shelf label system for displaying information using electronic shelf label displays (ESL system for short), where ESL stands for "Electronic Shelf Label," with a proprietary shelf rail subsystem is known, for example, from international patent application WO 2017 / 153481 A1. In this known ESL system, such a shelf rail subsystem is installed on each shelf rail. In this subsystem, the shelf rail is equipped with electrical conductors, with the help of which the ESLs of the shelf rail are controlled by a management module of the shelf rail. The ESLs have spring-loaded contacts on their backs, which are used to contact the conductors to electrically connect the ESLs to the management module.

[0003] However, this shelf rail subsystem is relatively expensive because a large number of mechanical components, particularly individual ones, are required in each ESL and each shelf rail. These mechanical components are subject to natural wear and tear. Furthermore, the mechanical components can become contaminated or even damaged if handled improperly. This can lead to malfunctions during operation. The mechanical components also involve considerable additional manufacturing and maintenance costs, which are necessary to avoid the aforementioned operational problems. The known system also has the limitation that the ESLs cannot be freely positioned or moved along the shelf rail.

[0004] EP0889425 A1 discloses a communication system comprising a central server and a series of electronic shelf labels, wherein the server communicates via a wireless connection with a shelf controller, and this shelf controller then communicates with the labels of the shelf.

[0005] US 2001 / 048057 A1 discloses a system in which a central controller can exchange information with shelf labels, the information exchange being carried out via a shelf rail with an induction loop.

[0006] The invention has for its object to provide an improved ESL system in which the above-mentioned problems are overcome. Summary of the invention

[0007] This object is achieved by an electronic shelf label system, wherein the system comprises a server configured to individually address a plurality of shelf labels in order to communicate data with them in an addressed manner, and wherein the system comprises at least one access point connected to the server and configured for radio communication of the data with the shelf labels, and wherein the system comprises a near-field communication, abbreviated NFC, sub-system on a shelf rail of a shelf, wherein the NFC sub-system is characterized in that the shelf rail comprises an NFC reader configured for radio-based communication with the access point, and that at least one conductor loop connected to the NFC reader, configured along the shelf rail and serving for NFC communication with an NFC-enabled shelf label, is provided,wherein at least one NFC-enabled shelf label is attached to the shelf rail corresponding to the conductor loop, and wherein the NFC reader is designed for NFC communication of the data with the shelf label addressed by the server.

[0008] The object is further achieved by a method for operating an electronic shelf label system, wherein in the system a plurality of shelf labels are individually addressed with the aid of a server and data is communicated with them in an addressed manner, wherein in the system the data is communicated with the shelf labels wirelessly via at least one access point connected to the server, wherein the system has a near-field communication, abbreviated NFC, sub-system on a shelf rail of a shelf, wherein the NFC sub-system is characterized in that the shelf rail has an NFC reader which is designed for radio-based communication with the access point, and that at least one conductor loop connected to the NFC reader, which is designed along the shelf rail and serves for NFC communication with an NFC-enabled shelf label, is provided,wherein at least one NFC-enabled shelf label is attached to the shelf rail corresponding to the conductor loop, and wherein, according to the method, the data between the NFC reader and the shelf label addressed by the server are communicated by means of NFC communication.

[0009] The object is further achieved by using a near-field communication, abbreviated NFC, sub-system on a shelf rail of a shelf of an electronic shelf label system, wherein the shelf rail has an NFC reader and at least one conductor loop connected to the NFC reader, which is formed along the shelf rail and serves for NFC communication with an NFC-enabled shelf label, and corresponding to the conductor loop at least one NFC-enabled shelf label is attached to the shelf rail, which is formed for NFC communication with the NFC reader, wherein the NFC sub-system is used to communicate data in an NFC communication with a shelf label addressed by a server of the system.

[0010] The measures according to the invention have the advantage that the shelf label to be attached to the shelf rail is completely free of electromechanical contacts and the associated problems. In contrast to the known subsystem mentioned above, in which each shelf label must have a special, proprietary electromechanical design, only one standardized NFC communication module is required in the shelf label to communicate contactlessly with the NFC reader forming a shelf rail management module (also called a shelf rail controller) according to a (common) NFC specification or NFC standard.

[0011] Especially given the typically high number of installed shelf labels (sometimes up to several tens of thousands in larger supermarkets), the integration of this standardized NFC module has a significantly positive impact on the cost structure of the overall system. This allows the shelf label to be manufactured much more cost-effectively and, because it eliminates the need for particularly maintenance-prone electromechanical components, also allows maintenance-free operation. Additional costs for the special shelf rail with its conductor loop are naturally inherent, but they are disproportionate to the manufacturing and operating costs that must be taken into account for the conventional shelf labels and the familiar shelf rails with their multitude of electromechanical contact elements.

[0012] In contrast to the known sub-system, in the present case only a single modified NFC reader is required per shelf rail. The modification essentially consists in the reader being designed (structurally speaking, an additional communication module) to communicate with the access point and to contact the conductor loop. However, in contrast to the known sub-system, this electro-mechanical contact is only required at the position of the NFC reader, which is preferably integrated into the shelf rail at the left or right end (e.g., can be attached to it, installed, or inserted). This in turn means that the shelf labels can be positioned randomly along the shelf rail, with the restriction to the position or extent of the conductor loop along the shelf rail, and can also be offset or freely (continuously) moved.Thus, in analogy to the positionability of paper-based shelf labels, the positioning of electronic shelf labels can be adapted to the actual positioning of the products.

[0013] If the shelf rails are excessively long, they can also be segmented and, depending on the number of segments, have a number of NFC readers with assigned conductor loop(s) per segment (i.e. at the location of the segments or within the segments).

[0014] The NFC subsystem in the electronic shelf label system acts as a switching device, enabling it to physically address the shelf labels addressed by the server, i.e., to communicate with them. In the NFC subsystem, communication is therefore NFC-compliant, with the server addressing the shelf labels, and the NFC subsystem implementing or applying this addressing, as discussed below in various training examples.

[0015] The data generated during communication can be status data, which is, for example, individually queried by the addressed shelf labels. However, it can also be command data, which represents commands that can be decoded and processed by the shelf labels and transmitted from the server to the addressed shelf label. These commands can, for example, trigger the query of status data or other functions or functionalities of the shelf label controller. However, the data can also be image content data, which is transmitted to a shelf label with a display medium in order to display image content there.

[0016] The server can be a physical computer located on the premises of a store, where it is responsible for controlling and managing the shelf labels and their activities, and on which corresponding control software is executed. However, the server can also be understood as a cloud solution, in which the control software is processed in a data center geographically detached from the store. The control software, among other things, establishes and stores a logical connection between individual shelf labels and products or product groups. It also manages a so-called planogram, which represents the spatial distribution of the shelf labels within the store. This control software can also perform goods logistics tasks.

[0017] Further, particularly advantageous embodiments and developments of the invention emerge from the dependent claims and the following description. Features of one claim category can be further developed according to the features of the other claim category, so that the effects and advantages cited in connection with one claim category also apply to the other claim categories.

[0018] In this system, different identifiers (identification data) are used to uniquely identify the devices integrated in the system, as follows: An access point identifier uniquely identifies each access point. The access point identifiers of the access points in the system are known to the server, i.e., stored there, because all communication with individual shelf labels runs via the respective access point to which the respective shelf label is wirelessly assigned, i.e., registered. A shelf label identifier uniquely identifies each shelf label for the server. In order to handle addressed data traffic with the shelf labels, the server also manages the unique shelf label identifier for each shelf label in use in the store. In particular, the server stores the association between the respective access point and the shelf labels assigned to that access point.A shelf label NFC identifier uniquely identifies each shelf label in the context of an NFC communication and is used again during such NFC communication with an NFC reader. A reader NFC identifier represents the counterpart on the NFC reader side and uniquely identifies an NFC reader for NFC communication with one of the NFC-enabled shelf labels. A reader identifier uniquely identifies each NFC reader and is required, for example, when registering the respective NFC reader with one of the access points in order to subsequently communicate wirelessly with this access point.

[0019] At this point, it should be noted that according to a first embodiment, it is sufficient for the server to know the shelf label identifier in order to address the respective shelf label, whereas according to a second embodiment, it is additionally necessary to know a reader identifier linked to the respective shelf label identifier in order to address the respective shelf label indirectly via the reader. This will be discussed in more detail below.

[0020] The electronic shelf label can provide a wide variety of functionalities or fulfill a variety of functions. The shelf label can, for example, be configured or designed to record environmental parameters, such as temperature or humidity, or as an input element for receiving input interaction from a user (e.g., capturing a fingerprint or keystroke), or as a display medium for presenting information to the user, namely as a shelf label display. In any case, the shelf label is designed such that it can be mechanically attached to the shelf rail in question and is supplied with energy and data there during NFC communication in the manner described in detail below.

[0021] The NFC-enabled shelf label features a standardized, first-ever NFC interface. This offers two advantages. This NFC interface serves, firstly, for local power transmission on the shelf or shelf rail, either for a single shelf label or a group of shelf labels attached to that shelf rail. Secondly, it also enables bidirectional local contactless data communication directly there. This allows the shelf labels to be supplied with power contactlessly, without the need for additional cabling or power supplies, etc.At the same time, this also avoids problems in radio communication caused by other radio systems in a store, because these are usually located far away from the shelves where the shelf label is installed and therefore have little to no influence on the local energy transfer as well as communication between the communication partners (NFC-enabled shelf label and NFC reader with its conductor loop(s)) positioned very closely together directly on the shelf rail.

[0022] As mentioned, NFC stands for Near Field Communication and the relevant standards are, for example, ISO / IEC 13157, -16353, -22536, -28361, etc.

[0023] The shelf label, when configured as a shelf label display, can feature an energy-saving display unit, such as an LCD. In particular, the technology used is based on electronic ink or electronic paper technology. Such a display unit has a reflective screen, also known in technical jargon as an electronic paper display (EPD), and is implemented using "electronic paper," or "e-paper" or "e-ink" for short. These terms essentially refer to the principle of an electrophoretic display, in which, for example, positively charged white particles and negatively charged black particles are contained in a transparent, viscous polymer. By briefly applying a voltage to electrodes between which the medium of particles and polymer is arranged, either the black particles are placed in front of the white particles, or vice versa, in the viewing direction.This arrangement then remains in place for a relatively long time (e.g., several weeks) without any further energy input. If the display is segmented accordingly, letters, numbers, or images can be realized with relatively high resolution to display the information in question. However, such a reflective screen can also be realized using other technologies, such as "electrowetting" or "MEMS." The screen can, for example, be designed for black-and-white, grayscale, black-white-red, or black-white-yellow, as mentioned above. Future developments that enable full-color or multi-color display are also to be included.Such a screen is generally a reflective, i.e. passive, non-self-illuminating screen in which the - relatively static - information reproduction is based on the fact that light generated by an external (artificial or natural) light source shines onto the screen and is reflected from there to the viewer.

[0024] Just like the other electronic components of the shelf label, this display unit is supplied with power and data, which can represent commands for controlling the display unit or image content, via the first NFC interface upon receipt of an NFC radio signal generated by the NFC reader. While the power is being supplied, the aforementioned data can also be transmitted via the first NFC interface, which is then processed by the display unit to change the image content on its screen. Once the image content has been changed, the display unit can also transmit corresponding status information via the NFC interface, representing the successful change of the image content.After the change to the image content has been completed, and if necessary also after the status information has been provided, the power supply via the NFC interface can be stopped, e.g. by stopping the generation of the NFC radio signal, after which the image content of the screen remains unchanged until the next desired change.

[0025] The use of the aforementioned technologies primarily allows the implementation of shelf labels, particularly those designed as shelf label displays, without their own power supply such as a battery or accumulator, both of which are relatively expensive. Furthermore, a conventional shelf label must be designed in such a way that the energy storage devices are replaceable for maintenance or replacement of the battery or accumulator. If necessary, the shelf label only uses a capacitor for short-term, temporary smoothing or stabilization of the internal supply voltage. The shelf label is therefore designed in such a way that its electronics for communication or updating the screen content, for receiving user interaction, or for recording environmental parameters, in particular its electronic control, are only active when powered by the NFC reader on the shelf rail.

[0026] However, the shelf label can also have – in addition to one or more smoothing capacitors and / or backup capacitors that may be provided – a long-term energy storage device for its at least temporary, autonomous energy supply. This long-term energy storage device can be implemented, for example, by a replaceable or rechargeable battery. Preferably, however, the long-term energy storage device is implemented by a so-called "supercapacitor," or "supercapacitor" for short, also called an "ultracapacitor." The advantage of such a capacitor is that it is a high-performance capacitor with a capacitance value that is much higher than that of conventional capacitors, yet the capacitor has lower voltage limits and bridges the gap between electrolytic capacitors and rechargeable batteries.It typically stores 10-100 times more energy per unit volume or mass than electrolytic capacitors, can absorb and release charges much faster than batteries, and tolerates many more charge and discharge cycles than rechargeable batteries. The shelf label's long-term energy storage is powered or charged by the NFC radio signal transmitted via the conductor loop, as long as the NFC radio signal is present. Charging can be done directly using a voltage generation stage that generates a supply voltage from the received NFC radio signal, or using the shelf label's own charging electronics. After the NFC radio signal is lost, the shelf label's electronics can be powered autonomously using the long-term energy storage, at least for a significantly longer period than would be possible with a backup capacitor or a smoothing capacitor.This allows the processing of commands or data even in the absence of the NFC signal, as well as the provision of other functionalities, such as processing user input or recording a temperature in a time range in which the NFC radio signal is not present.

[0027] The housing of the shelf label can be completely and permanently encapsulated because replacement of the energy storage device is no longer necessary, so that it can only be opened for recycling purposes (e.g. with special tools).

[0028] This makes it possible to create a shelf label that is reduced to just a few essential electronic components, making it extremely cost-effective. This extremely reduced shelf label only needs to have basic functionality, such as standardized NFC communication with a standardized power supply during NFC communication, which is implemented using a commercially available NFC module.

[0029] Updates of the screen of the energy-saving display unit and status reports or the transmission of data concerning a user interaction or an environmental parameter are not carried out directly by the shelf label display in communication with an access point, as is the case with known systems, but rather by the intermediate NFC reader, which in turn is in radio contact with the access point, which will be discussed in more detail below.

[0030] As mentioned, a conductor loop is formed on the shelf rail, and the loop connections of this conductor loop are connected to the shelf rail's NFC reader. The conductor loop thus forms a component of the NFC reader for contactless NFC communication with the NFC-enabled shelf label, which is mounted on the shelf rail corresponding to the conductor loop. "Contactless" here means that this can be achieved using an inductive coupling between two adjacent conductor loops or coils. For this purpose, the shelf label also has a conductor loop consisting of a single loop or a plurality of windings, i.e., a coil. However, the signal transmission from the NFC reader to the NFC-enabled shelf label can also be achieved by transmitting the NFC radio signal and receiving it with an antenna on the shelf label.The NFC reader comprises a transmitter with an antenna configuration that is essentially determined by the conductor loop. It will be readily apparent to those skilled in the art that an antenna matching network and a transmitter stage, a modulator, and a demodulator, etc., are also present. These components and their interconnection to analog antenna components can be found in the relevant application notes from NFC reader IC manufacturers.

[0031] To receive the NFC signal, the shelf label also has a conductor loop consisting of a single loop or turn or a plurality of turns, i.e., a coil. This coil is part of the shelf label's first NFC interface. Here, too, the specific implementation can be found in the relevant "application notes" of the NFC IC manufacturers.

[0032] Furthermore, "corresponding to" means that the shelf label is positioned adjacent to the area spanned by the conductor loop and is located there essentially within a zone delimited by the conductor loop. The conductor loop itself can be formed in the plane of the shelf rail, e.g. visibly, or covered by a protective material (strip). If the shelf label is inserted into the shelf rail (i.e. mechanically fastened there), the conductor loop or coil built into the shelf label is automatically located in the zone that can be used for the inductive coupling between the two conductor loops or coils positioned next to each other. For the shelf label inserted into the shelf rail, the conductor loops or coils are preferably in the zone delimited by the two conductor loops or coils.The surfaces spanned by coils (one belonging to the shelf rail and the other to the shelf label) are oriented parallel to one another and located at a distance of less than one millimeter to several millimeters. To avoid impeding the transmission of the NFC radio signal, the shelf rail itself is made of a suitable material, preferably plastic. It can also have a shielding plate on its rear side to achieve a defined attenuation of the antenna resonant circuit of the NFC reader. This enables the antenna resonant circuit to be tuned to this defined environment and thus contributes significantly to communication security because metallic loads in the vicinity of the NFC reader are thus largely negligible.

[0033] The circumference of the conductor loop of the shelf rail can, for example, extend along the entire length of the shelf rail and at least part of the entire height of the shelf rail. To implement the conductor loop, a single circumferential conductor track or a coil-like multiple circumferential conductor track, i.e. a conductor track with several turns, can be provided. Multiple conductor loops or coils can also be installed along the shelf rail and connected to the NFC reader. In this context, it can be advantageous for the NFC reader to be designed to multiplex the conductor loops. Only a single conductor loop, which is electronically selected, is ever used to transmit the NFC radio signal. It has proven particularly advantageous to use exactly one NFC reader per shelf rail, because this allows the use of an NFC reader without a conductor loop multiplexer.This allows the use of a conventional NFC IC (Integrated Circuits) to supply power to an entire shelf rail.

[0034] The power supply for the NFC reader on the shelf rail can be implemented in different ways. For example, the NFC reader can be supplied with power from a separate power supply unit. A group of NFC readers can also be supplied with power from a central power supply unit. However, the NFC reader is particularly preferably designed to be supplied with power via radio. This requires a power supply station, which in turn is designed as a radio energy source for supplying the NFC reader with power, in particular in a directed, radio-based manner. The power supply station thus enables contactless, targeted energy transfer to the NFC reader. This enables an essentially cable-free supply infrastructure for the shelf labels attached to the shelf rail, on the one hand, and for the NFC reader intended to supply the shelf labels, on the other hand.In effect, the system installer eliminates the need for cabling between the actual power source and the respective shelf. This allows for essentially unlimited positioning of shelves within the store, as well as the arbitrary and easy positioning of shelf rails on various shelves, as well as their exchange between shelves. This type of energy transmission, as well as the underlying technology, is known under the term "Power over WiFi." Wireless energy sources equipped with this technology can be installed, for example, on the ceiling of a store and selectively supply the NFC readers assigned to the respective shelf rails and located within a radius of up to 10 meters using powerful, focused radio signals directed at them.

[0035] In addition to the NFC interface, which is intended for communication with the NFC-enabled shelf labels, the NFC reader has a further interface, namely the additional communication module already mentioned, which is intended for communication with the access point. This further interface is designed for radio communication and accordingly has a radio transceiver for communication in the 2.4 GHz radio band, for example. The transceiver is an electronic device that is designed to both receive and transmit radio signals and has the necessary functionality to modulate a carrier signal and demodulate received signals. The transceiver can be implemented using active and passive electronic components or assemblies, such as a matching network for an antenna and antenna configuration, etc., with the help of which analog signals can be converted into digital signals and vice versa.The transceiver can be coupled to a logic stage. The logic stage can, for example, be implemented entirely using discrete hardware or comprise a microprocessor and memory chips, or a microcontroller with integrated memory chips, allowing software stored in the memory chips to be processed. The NFC reader can receive a radio signal from the access point using its transceiver, process the received data contained in the radio signal using the logic stage, and, if necessary, generate response data using the logic stage and transmit this response data back to the access point via the transceiver as a radio signal. From a communications perspective, the NFC reader thus implements a "gateway" for all the shelf labels mounted on the relevant shelf rail.

[0036] Similarly, the access point is also equipped to communicate wirelessly with the NFC reader. Wireless communication can be carried out using Wi-Fi, ZigBee, or Bluetooth communication protocols.

[0037] Particularly preferably, the access point and the NFC reader are designed for radio-based communication according to a (proprietary) time slot communication method, wherein in the time slot communication method a number of time slots per time slot cycle are available for communication in a repeating sequence, wherein preferably each time slot is identified by a unique time slot symbol.

[0038] Preferably, a proprietary time slot communication method is used, as is known in principle from WO2015 / 124197, pages 2 to 4, as well as Figures 1-8C with associated description, wherein in the present case not the shelf labels but the NFC reader is designed to communicate with the access point according to this time slot communication method, as follows.

[0039] According to this proprietary time slot communication method, the access point communicates with a number of NFC readers in such a way that, in a continuously repeating sequence, a number of time slots are available for communication per time slot cycle. Each time slot is uniquely identified by a unique time slot symbol and can therefore be distinguished from other time slots solely by the time slot symbol. According to this method, the access point transmits a synchronization data signal for the currently available time slot, comprising the time slot symbol at the beginning of the respective time slot. The NFC readers are familiar with this systematic time slot communication method and are designed to switch from an (extremely energy-saving) sleep state, in which, for example, there is no readiness to receive a radio signal, to an active state, in which, for example,a radio signal reception readiness exists, and to receive the synchronization data signal in the active state, and, if the received time slot symbol indicates a time slot intended for the respective NFC reader, to define a new wake-up time corresponding to the next occurrence of the time slot intended for this NFC reader in a time slot cycle following the currently present time slot cycle.

[0040] This has the advantage that synchronization between the access point and one of the NFC readers is detected, maintained, and ensured throughout system operation in the simplest yet most robust way possible. This also improves the energy efficiency of all NFC readers logically assigned to a single access point, because the synchronization check takes place immediately at the beginning of the time slot. The subsequent behavior of the NFC reader then depends on whether one of the shelf labels installed on its shelf rail or the reader itself is addressed in the time slot assigned to it.

[0041] In principle, the synchronization data signal could be formed exclusively by the time slot symbol, and other communication parameters required for communication with the access point (or server), such as address data for addressing or command data for transmitting commands, could be separated from the synchronization data signal. However, since the time slot symbol is preferably an extremely compact indicator for synchronizing communication within the system, and can therefore be formed, for example, by the consecutive number of the time slot, it is advisable to embed additional information in the synchronization data signal in addition to the time slot symbol, which will be discussed below.

[0042] It is therefore advantageous if the access point is designed to embed address data into the synchronization data signal, with the help of which a number of NFC readers and / or shelf labels can be individually addressed per time slot.

[0043] Analogous to what was previously said about embedding address data, a further significant contribution to system efficiency is achieved if the access point is designed to embed command data into the synchronization data signal, which leads to command execution by the addressed device (NFC reader and / or shelf labels). However, even without individual addressing, a command can be transmitted to all devices assigned to a specific time slot, which can then be executed by a relatively large group of devices, for example, all of them.

[0044] In principle, the shelf label could perform a standardized (predefined) task simply by recognizing its individual address, without having to receive an explicit command. However, it has proven particularly advantageous if address data for addressing an individual shelf label and command data for transmitting a command to this individual shelf label are transmitted, and the shelf label is configured to evaluate the command data and execute the command when it is individually addressed using the address data. Thus, a command for a single shelf label can be transmitted in a sometimes relatively large group of shelf labels.

[0045] It is therefore initially sufficient for each NFC reader that is involved in communication with the access point in question, i.e. is assigned to it wirelessly, e.g. through initial registration, to know the time slot symbol that indicates its designated time slot. Each NFC reader therefore individually orients itself to the appearance of a time slot symbol relevant to it, identifies the time slot symbol relevant to it, and defines its next wake-up time in order to remain synchronized with the timing of the time slot communication process specified by the communication station. As mentioned, this timing is known to the NFC reader. It is entirely sufficient for the time slot symbol to uniquely identify the respective time slot, e.g. with a time slot identifier that is individual for each time slot.Additional information encoded in the synchronization data signal, as is often the case with other methods, is unnecessary here to ensure the NFC reader operates synchronously with the access point to which it is wirelessly assigned. The NFC reader thus determines its synchronization with the access point solely by recognizing the time slot symbol, which appears at the expected time or within an expected time window and indicates the time slot assigned to it.

[0046] Once the NFC reader has established its synchronization as previously discussed, it is generally sufficient for it to return to the sleep state, because the next wake-up time is automatically determined by the time frame of the time slot communication method known to it. Defining the new wake-up time can therefore be limited to restarting a timing control stage (e.g., a timer) of the NFC reader with the timing parameters previously used to switch from the sleep state to the active state. The affected NFC reader can then return to the sleep state and remain there until it is triggered by the timing control to wake up again and switch from the sleep state to the active state at the new wake-up time in the next time slot cycle.However, the NFC reader does not necessarily have to remain in sleep mode for the remainder of its allocated time slot; it can also process other tasks, such as NFC communication with one of the shelf labels, in its active state during the time slot or even the time slot cycle. The previously discussed time control then operates in the background, independently of the other, ongoing activities of the NFC reader. The new wake-up time can be defined by specifying an absolute or relative time, such as relative to the time of occurrence of the synchronization data signal, relative to the time at which the sleep state is resumed after the active state, or relative to the time at which the synchronization data signal ends.However, the definition of the new wake-up time can also be understood in such a way that the duration of the sleep state following the active state in which the time slot symbol was received, or the sum of the duration of the sleep state and the active state, or the sum of the duration of several such state sequences, determines the new wake-up time.

[0047] Since each NFC reader operates its own timing stage and exemplary variations in the behavior of the respective electronic components cannot be ruled out, defining the new wake-up time may also include compensation for a time base drift that is unique to each NFC reader. For this purpose, for example, a time difference between the expected occurrence of the synchronization data signal with the time slot symbol indicating the time slot designated for the respective NFC reader and the actual occurrence can be measured in the NFC reader and taken into account in the timing stage to correct its timing. However, compensation is only used when synchronism is detected.

[0048] However, if a different time slot symbol was received instead of the expected time slot symbol, there is no synchronism and the NFC reader must resynchronize. For this purpose, such an asynchronous NFC reader does not switch periodically, as would be the case in a synchronous state, but rather, for example, switches from its sleep state to its active state once at any time and remains in this active state in readiness to receive. If nothing is received within a certain period of time, such as the duration of a time slot, it switches back to the sleep state and repeats the reception attempt at a different time. As soon as a synchronization data signal is received, the time slot symbol is evaluated, i.e. checked. The time slot symbol received in this way most likely indicates a time slot not intended for the respective NFC reader, which is determined autonomously by the NFC reader.The NFC reader knows the systematic occurrence of the time slot symbols and, after evaluating the received time slot symbol, can independently decide whether it can expect the time slot designated for it to occur within the current time slot cycle (first case) or only in the subsequent time slot cycle (second case). For the first case, the NFC reader is designed to define a new wake-up time in the current time slot cycle that corresponds to the next occurrence of the time slot designated for it. By evaluating the received time slot symbol and knowing the systematic occurrence of the time slot symbols, the NFC reader determines that the time slot designated for it will occur within the current time slot cycle.For the second case, the NFC reader is configured to define a new wake-up time corresponding to the next occurrence of the time slot designated for it in the time slot cycle following the current time slot cycle. By evaluating the received time slot symbol and knowing the systematic occurrence of the time slot symbols, the NFC reader determines that the time slot designated for it will no longer occur in the current time slot cycle because it already occurred in this time slot cycle in the past. As discussed in the introduction to the synchronous state, the aforementioned time control is also used for this type of definition of the new wake-up time, whereby the time control is now operated with the timing parameter with which the desired entry into the synchronous state is achieved.The timing parameter to be selected for the supply device results from the inherent knowledge of the time slot communication method used. The timing parameter is therefore determined by the NFC reader's electronics, which has knowledge of the parameters of the time slot communication method.

[0049] These parameters can be queried by the NFC reader during its registration with the respective access point or transmitted to the access point, or they can be pre-programmed into the NFC reader. In both cases, it is expedient for the NFC reader to have a memory level for storing the parameters of the time slot communication method, and for the NFC reader to be designed to access and consider these parameters for the purpose of defining the new wake-up time. The parameters can represent all details of the timing of the time slot communication method, such as parameters relating to time sequences for communication between the access point and the NFC reader, parameters relating to predefined times or time periods, and also parameters relating to the basic structure of the time slot communication method, such as:Number of time slots, the duration of a time slot, the duration of the time slot cycle, or also as parameters the explicitly specified time slot symbols for identifying the individual time slots or even algorithms for calculating the time slot symbols. With the help of these parameters, an asynchronous NFC reader can autonomously, i.e. automatically, without external intervention, clarify whether, based on the time slot symbol just received, the time slot intended for it can still be expected within the current time slot cycle, or whether the time slot intended for it in the current time slot cycle already belongs to the past and therefore the next time slot intended for it will not occur until the next time slot cycle.The affected NFC reader calculates the new wake-up time in the active state, switches to the sleep state, and switches to the active state at the calculated wake-up time. It receives the time slot symbol of its designated time slot and then returns to the synchronous state. If no further activity is expected from it in the current time slot, it immediately switches to the sleep state and then returns to the active state in the next time slot cycle to receive the synchronization data signal in its designated time slot.

[0050] The fact that the NFC reader in question knows about the time slot symbol that indicates the time slot intended for it, i.e. knows when exactly it has to be in the active state in order to be available for communication, arises in different ways and ultimately depends on which of the two training methods discussed below is used.

[0051] According to a first embodiment, the NFC reader stores a data structure that represents an assignment of a shelf label attached to its shelf rail to one of the time slots, and wherein the NFC reader is designed to check the time slot to which a shelf label is assigned according to the data structure to determine whether the shelf label attached to its shelf rail is addressed by the server.

[0052] In this case, the data structure consists of the shelf label identifier, which is also known to the server and used by it for addressing, and the corresponding time slot symbol. These form a data pair of the data structure for each shelf label attached to the shelf rail of the NFC reader. If several shelf labels attached to this shelf rail are assigned to a specific time slot, which is technically feasible, their shelf label identifiers can also be grouped and assigned to the respective time slot symbol, or separate data pairs consisting of the respective shelf label identifier and the corresponding time slot symbol can be stored in the data structure.The data structure also includes a shelf label NFC identifier for each shelf label identifier intended for addressing by the server, which is used in an NFC communication between the NFC reader and the shelf label in order to address the NFC-enabled shelf label at the NFC communication level.

[0053] Furthermore, the NFC reader is designed to transmit data between the addressed shelf label and the access point if a positive test result is present. Depending on the design variant, this data can either be transmitted to the NFC reader in the time slot specified for the addressed shelf label according to the data structure or split up into several additional time slots. Depending on whether the data is time-critical, this data can then be communicated with the relevant shelf label within the NFC subsystem in real time, i.e. in the respective time slot. If the data is not time-critical, it can first be received in the respective time slot during a scheduled transmission to the shelf label and temporarily stored in the NFC reader. It can then be transmitted to the shelf label in an NFC communication, independent of the timing of the time slot communication process.The same applies to data retrieved from the shelf label. This data can also be collected and temporarily stored within the NFC subsystem, i.e., the NFC reader, independently of the time slot communication process, and then transmitted to the access point via the NFC reader in the designated time slot.

[0054] The data can be command data or content data. Content data is often linked to command data. For example, a display control command with image data forming content data can be transmitted to a shelf label with a display unit. Likewise, a query command can be used to query temperature data from an addressed shelf label that has a temperature sensor, etc.

[0055] In this case, the NFC reader's design is characterized in such a way that, as mentioned, the NFC reader has its energy-saving sleep state, in which it is not ready to communicate with the access point, and its active state, in which it is ready to communicate with the access point. The NFC reader is designed to switch from the sleep state to the active state in a timely manner when the time slot to which a shelf label is assigned according to the data structure occurs. This means that the NFC reader can be in its active state multiple times within a time slot cycle for the purpose of checking synchronization and addressing. Specifically, the number of these active states depends on how many time slots are assigned to the shelf labels assigned to it on the shelf rail.

[0056] The data structure allows the synchronous NFC reader to be in the active state at the time the respective time slot symbol occurs and to check whether one or more of its shelf labels, which are noted in its data structure, are addressed by the server using the address data.

[0057] In this case, the server implements a system that stores an individual shelf label identifier for each shelf label in a database and addresses the respective shelf label directly based on the shelf label identifier. As mentioned at the beginning, the access point identifier is also used here to address the access point through which the respective shelf label can be wirelessly addressed.

[0058] A significant advantage of this embodiment is its backward compatibility with the one in the aforementioned WO2015 / 124197. Accordingly, the software application running on the server does not need to have any knowledge of the NFC subsystem. However, compared to the system disclosed in WO2015 / 124197, this embodiment already has a significantly better system energy balance when two or more shelf labels are installed per shelf rail, with the two or more shelf labels being assigned to a single time slot. In the system of WO2015 / 124197, each shelf label must be in the active state at least once per time slot cycle to verify its synchronous state and subsequently check whether it is addressed.In contrast, in the present embodiment, only the NFC controller to which the two of the multiple shelf labels are assigned needs to be in the active state in the appropriate time slot in order to verify the synchronization and to check whether one or more of the shelf labels are addressed.

[0059] In contrast to the previously discussed embodiment, according to a second embodiment, the NFC reader itself is assigned to one of the time slots and stores a data structure representing the shelf labels attached to the shelf rail of the NFC reader, and the NFC reader is designed to check the time slot to which it is assigned to determine whether the shelf label attached to its shelf rail is addressed by the server.

[0060] In the present case, however, the addressing performed by the server concerns the primary, i.e., direct, addressing of the NFC reader, via which one of its shelf labels is then indirectly addressed. The indirect addressing of the shelf label is transmitted to the addressed NFC reader, for example, in the form of the command data mentioned in connection with the discussion of the time slot communication method. This command represents an indirect addressing command that has the shelf label identifier of the shelf label to be indirectly addressed as an argument, in the time slot to which the NFC reader is assigned.

[0061] In this case, the data structure consists of the shelf label identifiers of the shelf labels attached to the shelf rail of the respective NFC reader. The data structure also includes a shelf label NFC identifier for each shelf label identifier intended for addressing by the server. This identifier is used in NFC communication between the NFC reader and the shelf label to address the NFC-enabled shelf label at the NFC communication level. Furthermore, the data structure can also include the time slot symbol, which identifies or indicates the time slot intended for the NFC reader.

[0062] Furthermore, the NFC reader is designed to transmit data between the addressed shelf label and the access point in the time slot specified for it if the test result is positive.

[0063] With regard to the processing of data in the NFC sub-system, the considerations and mechanisms mentioned in connection with the previously discussed form of training can be applied in an analogous manner.

[0064] In this case, the NFC reader is designed such that it has an energy-saving sleep state, in which it is not ready to communicate with the access point, and an active state, in which it is ready to communicate with the access point. The NFC reader is designed to switch from the sleep state to the active state in a timely manner with the occurrence of the time slot to which it is assigned. This means that a synchronous NFC reader is only in the active state once within a single time slot cycle to check its synchronism and whether it is addressed in the time slot intended for it. It should be noted here that multiple NFC readers can also be assigned to a single time slot.

[0065] In the present case, the implementation on the server side is such that the server stores in a database a link between a reader identifier of an NFC reader and a shelf label identifier of the shelf label installed on the shelf rail of the NFC reader and addresses a shelf label indirectly via the link between the shelf label identifier of the shelf label to be addressed and the reader identifier.

[0066] In contrast to the first embodiment, the second embodiment is no longer backward compatible with that of the aforementioned WO2015 / 124197, because the system according to WO2015 / 124197 simply does not provide any means of storing and managing the reader identifier, and using it to address the shelf labels. In contrast, however, the second embodiment is significantly more energy-efficient than the solution of WO2015 / 124197, and also compared to the solution according to the first embodiment, as long as two or more shelf labels are installed per shelf rail. In the system of WO2015 / 124197, each shelf label must be in the active state at least once per time slot cycle in order to verify its synchronous state and subsequently check whether it is addressed.The same applies to the first embodiment, whereby the NFC reader must be in the active state twice per time slot cycle if two shelf labels assigned to different time slots are installed on its shelf rail. In contrast, in the present embodiment, it is sufficient for the NFC reader to be in the active state only once per time slot cycle to verify its synchronous state and subsequently check whether it is addressed. This is particularly independent of how many shelf labels are installed on its shelf rail.

[0067] According to a preferred embodiment of the shelf label, the shelf label has an energy-saving display unit, in particular based on electronic ink or electronic paper technology, etc., which significantly contributes to the energy efficiency of the system. Such a display unit requires no energy consumption, except for changes in the image content.

[0068] Particularly preferably, the shelf label comprises a rechargeable electrical energy storage device, preferably the aforementioned long-term energy storage device, and is configured for contactless charging of the energy storage device using an NFC radio signal from the NFC reader. This implementation fully exploits the potential of the NFC subsystem because not only are addressing and data traffic handled via the NFC subsystem, but the NFC subsystem also ensures autonomous operation of the shelf labels even during periods in which no NFC radio signal is present, without any cabling and / or maintenance effort that would otherwise be required for replacing batteries and disposing of used batteries or recharging rechargeable batteries.

[0069] In general, it should be noted that in this system, each access point installed serves as a higher-level interface between the server or its software application and the NFC subsystem registered with the respective access point. At the shelf rail level, this interface function is performed by the NFC reader, which serves as a subordinate interface between the shelf labels installed on its shelf rail and the access point to which the respective NFC reader, and thus also the respective NFC subsystem to which the NFC reader belongs, is logically (radio-technically) assigned.

[0070] In a business premises of a supermarket, for example, several access points can be installed, with each access point being designed to communicate with the NFC readers logically assigned to it, which are located in a geographical (radio-accessible) area around it.

[0071] If multiple shelf labels are arranged corresponding to a conductor loop of the shelf rail, or if multiple shelf labels are supplied with power simultaneously via a single conductor loop, precautions must be taken to ensure reception of the respective shelf label identifier or shelf label NFC identifier. To this end, the shelf labels can, for example, be programmed to transmit their identifier at randomly selected times within a time window (single or multiple times) to ensure individual reception by the NFC reader of the shelf rail. Likewise, an anti-collision process known from RFID technology, for example, can be used for this contactless transmission to ensure individual reception by the NFC reader of the shelf rail.In technical jargon, the detection of NFC-enabled shelf labels attached to the shelf rail is referred to as going through a polling loop, whereby the NFC reader checks which shelf labels are present and records their shelf label NFC identifier.

[0072] The shelf label identifier retrieved from the shelf label by the NFC reader is forwarded by the NFC reader in communication with the access point to the store's server, which carries out or coordinates the communication with the individual electronic shelf labels in order to subsequently retrieve data from them or transmit data to them.

[0073] The server also stores the logical link between products displayed on the respective shelf and the shelf labels (displays) positioned there, thus ensuring that the respective shelf label display presents the information that belongs to the product positioned corresponding to the shelf label.

[0074] The server can also be informed about the position or extent of the respective conductor loop on the shelf rail and, along with the shelf label identifier, can also be informed by the respective NFC reader about which conductor loop was used to obtain the shelf label identifier from the shelf label. This also allows the creation of three-dimensional digital maps of the positions of all shelf labels in a store. This applies both to shelf labels configured to display information (shelf label displays) and, in a similar way, to those shelf labels that provide the other possible functionalities mentioned.

[0075] The electronics of the various devices, components, and / or assemblies of the system, as well as their interfaces, etc., can be implemented using a wide variety of passive and active electronic components or functional units, both discretely and in an integrated manner. A microprocessor with corresponding peripheral components or a microcontroller is preferably used, on which software is executed to provide the various functionalities. So-called ASICs (Application-Specific Integrated Circuits) can also be used.

[0076] These and other aspects of the invention are apparent from the figures discussed below. Short character description

[0077] The invention will be explained in more detail below with reference to the accompanying figures using exemplary embodiments, to which, however, the invention is not limited. In the various figures, identical components are provided with identical reference numerals. They show schematically: Fig. 1 shows a section of an electronic shelf label system according to the invention with an "intelligent" shelf rail; Fig. 2 shows an embodiment of a shelf label as a block diagram; Fig. 3 shows an embodiment of the shelf rail as a block diagram with an NFC sub-system; Fig. 4 shows a shelf rail with a shelf label in a perspective view; Fig. 5 shows a sectional view of the shelf rail; Fig. 6 shows an exploded view of the shelf rail; Fig. 7 shows a state diagram of system component activities according to a first embodiment; Fig. 8 shows a state diagram of system component activities according to a second embodiment. Description of the embodiments

[0078] In the Figure 1A shelf label system 1 is shown, which comprises a number of identically designed electronic NFC-enabled shelf labels 2A-2K implemented as shelf label displays, which are attached to three "smart" shelf rails 3. Each of the shelf rails 3 has an NFC subsystem. A component of each NFC subsystem is an NFC reader 4A-4C. The NFC reader 4A-4C is inserted laterally into the shelf rail 3. Furthermore, each shelf rail 3 has, as a component of the NFC subsystem, a conductor loop L that extends along the entire length of the shelf rail 3 and whose conductor loop connections C are electrically connected to the NFC reader 4A-4C. The conductor loop L forms the antenna of the respective NFC reader 4A-4C and is thus a component of the respective NFC reader 4A-4C that is integrated into the shelf rail 3.As soon as shelf labels 2A-2K are installed on the respective shelf rail 3 corresponding to their conductor loop L and have been detected by the NFC reader 4A-4C there, these shelf labels 2A-2K also form a component of the respective NFC sub-system of the shelf rail 3.

[0079] The respective NFC reader 4A-4C acts as a shelf rail controller for controlling the shelf labels 2A-2K installed on its shelf rail 3. The respective NFC reader 4A-4C communicates with the NFC-enabled shelf labels 2A-2K installed on its shelf rail 3 according to an NFC communication protocol. To do so, it transmits an NFC radio signal via the conductor loop L, which is used by the respective shelf label 2A-2K for both power supply and data transmission.

[0080] Also shown is a data processing device which in the present case is implemented with the aid of a server 5 which is connected by cable to an access point 6 which, for example, has two antennas 7.

[0081] The NFC readers 4A-4C are further modified such that they are in radio contact with the access point 6 via first radio signals F1 according to a proprietary time slot communication method. This allows, for example, the image content of the shelf labels 2A-2K to be changed from the server 5 and, if necessary, also to query associated status information from the shelf labels 2A-2K and transmit it to the server 5.

[0082] Each of the shelf rails 3 is mounted on an individual shelf 8 at its front edge. The three illustrated shelves 8 all belong to a shelf 9 that is only indicated very schematically. Various products can be stored on the shelves 8, although these are not shown in this case for the sake of simplicity.

[0083] Furthermore, the NFC readers 4A-4C are configured such that they can themselves be supplied with energy using a second radio signal F2. For this purpose, the system 1 comprises a supply transmitter 10 (also referred to as a radio energy source) configured to transmit electrical energy to a receiver (i.e., to one of the NFC readers 4A-4C) using the focused or directed (second) radio signal F2 with a specific transmission power, such as 5 W. Such a supply transmitter 10 also comprises a plurality of antennas 11 (six are shown here), with the aid of which the direction of energy transmission (ultimately the propagation of the second radio signal F2) can be adjusted relatively precisely, so that the energy-transmitting second radio signal F2 arrives precisely at the respective NFC reader 4A-4C. This energy transmission is known under the term "Power over WiFi."

[0084] It should be noted at this point that, for the sake of simplicity, only a single access point 6 and a single shelf 9 have been visualized. However, in a real supermarket environment, numerous such system components are present. There, a single access point 6 would provide wireless coverage to numerous shelves 9 in its vicinity.

[0085] Below is a block diagram of the shelf labels 2A-2K based on the Figure 2 discussed, whereby for the sake of simplicity the reference number 2 was used for the identically designed shelf labels 2A-2K.

[0086] The block diagram shows a first NFC interface 12 with its coupling coil or antenna 13. With the help of the coupling coil 13, the NFC radio signal can be received by another NFC-enabled device, in this case the NFC reader 4A-4C. For this purpose, the coupling coil 13 must be positioned sufficiently close (a few tenths of a millimeter to approximately 4 millimeters) to the conductor loop L, which is the case with the shelf label 2 attached to one of the shelf rails 3. During the existence of the NFC radio signal, a first supply voltage VCC1 (relative to a local first reference potential GND1) for the operation of the entire shelf label 2 is generated with the help of the NFC interface 12.

[0087] Specifically, the first NFC interface 12 has electronics 12A designed to generate the first supply voltage VCC1 and to provide NFC communication capability. Furthermore, the electronics 12A has a long-term energy storage device, in this case implemented as a supercapacitor 12B, with the aid of which the first supply voltage VCC1 can be maintained for longer periods of time than would be the case with a smoothing capacitor or backup capacitors (both not shown), even in the absence of the NFC radio signal. This allows the shelf label 2 to operate even in the absence of the NFC radio signal and to perform tasks such as, with appropriate design, temperature detection or user inputs. The supercapacitor 12B is charged with the aid of the electronics 12A when the NFC radio signal is present.

[0088] As soon as the electronics 12A have been activated using the NFC radio signal, the first NFC interface 12 is also available for contactless bidirectional communication of data D. Part of this electronics 12A is an NFC tag controller, which provides the entire NFC functionality. It is not shown in detail here, but is integrated into the first NFC interface 12.

[0089] The block diagram also shows a display unit 14 connected to the first NFC interface 12, which is divided into an electronic paper display controller 15, or EPD controller 15 for short, and an electronic paper display screen 16 that can be controlled by the controller. With the help of the EPD controller 15, the data received via the first NFC interface 12 is interpreted, the image content of the screen 16 is modified accordingly if necessary, or status information in the form of data D is transmitted to the NFC reader 4A-4C via the first NFC interface 12.

[0090] In the following, based on the Figure 3 A block diagram of the shelf rail 3 is discussed. Analogous to the description of the shelf labels 2A-2K, the reference number 4 was used here for the identically designed NFC readers 4A-4C.

[0091] In the Figure 3 It is indicated that shelf rail 3 has shelf labels 2G-2K, which means that it is the shelf labels shown in the Figure 1 The shelf labels 2G-2K are positioned corresponding to the position of the conductor loop L. In contrast to the Figure 1The electrical connection of the loop terminals C to a second electronics unit 18A of the NFC reader 4 is also visible. The conductor loop L, together with the second electronics unit 18A, forms a second NFC interface 18 of the NFC reader 4. Here, too, the second electronics unit 18A has its own NFC reader controller (not shown), which provides the entire NFC reader functionality. Using the second NFC interface 18, the NFC radio signal can be generated and emitted, thus transmitting electrical energy to the shelf labels 2G-2K in a contactless manner and enabling bidirectional data communication with them.

[0092] It should be emphasized at this point that the conductor loop L, although it is a component of the NFC reader 4, is incorporated outside the NFC reader 4 in the mechanical structure of the shelf rail 3. This is symbolized by a structure 17 of the shelf rail 3 that encloses the conductor loop L and connects to the NFC reader 4.

[0093] The NFC reader 4 further comprises an access point communication module 19, which is used for radio-based communication with the Figure 1illustrated access point 6. For this purpose, the access point communication module 19 has a specially designed electronics (not shown in detail) and an antenna configuration 19A, which may also comprise multiple antennas. To control the internal processes and the communication according to the aforementioned proprietary time slot communication method with the access point 6, the supply device 4 has a control unit 20. The control unit 20 is implemented using a microcontroller, which is connected to the second NFC interface 18 and the access point communication interface 19 via a bidirectional data bus.

[0094] To implement the "Power over WIFI" energy transmission, the NFC reader 4 has a supply receiver 21 suitable for receiving the second radio signal F2, which is equipped with its antenna configuration 22 (which can have multiple antennas) and electronics (not shown in detail) designed to receive the second radio signal F2 and to store the energy transmitted thereby in an internal electrical energy storage device 23 (rechargeable battery, accumulator or supercap, etc.) and thus to generate a second supply voltage VCC2 with respect to a second reference potential GND2 for the electrical supply of the NFC reader 4.

[0095] The control unit 20 is also connected to the supply receiver 21 via its data bus.

[0096] During operation, the NFC reader 4 can, for example, query or monitor the charge level of the energy storage device 23 with the aid of its control unit 20. As soon as the charge level drops below a certain level, the control unit 20 can request a (re)charge using the first radio signal F1. This request is received by the access point 6 and, depending on the implementation, can be forwarded directly to the supply transmitter 10 or, with the involvement of the server 5, to the supply transmitter 10. Since the exact geographical position (the three-dimensional coordinates) of each of the NFC readers 4 in the store as well as their unique reader identifier are known in system 1 (e.g., the server 5), the supply transmitter 10 can transmit the second radio signal F2 precisely directed towards the position of the respective NFC reader 4 requesting the charge.There, the second radio signal F2 is received and the energy transmitted with it is used to charge the internal energy storage device 23.

[0097] The shelf rail 3 described here is therefore designed, with the aid of its NFC sub-system, for contactless communication with the shelf labels 2 installed on it and an access point 6 assigned to it by radio technology, and for contactless energy provision in the sense of energy storage for the operation of the NFC reader 4 itself as well as for the contactless energy supply of the respective shelf labels 2.

[0098] At this point it should also be mentioned that the supply transmitter 10 can also be installed in the access point 6.

[0099] In a further step, based on the Figure 4-6 the structure of the "intelligent" shelf rail 3. The Figure 4a shelf rail 3 with a shelf label 2 attached to it and the NFC reader 4 inserted laterally into the shelf rail 3, which is fastened to the structure of the shelf rail 3 with screws 24. This shelf rail 3 has, for example, a length of approximately 3 m, a height of approximately 4.5 cm, and a thickness of 1.2 cm.

[0100] The Figure 5 shows a section through the shelf rail 3 according to a Figure 4drawn section AA, which is oriented transversely (aligned normal to the front of the shelf rail 3) through the shelf rail 3 and runs at the point at which contact elements 25 of the NFC reader 4 are formed, which serve to contact the conductor loop L of the NFC reader 4 running in the shelf rail 3. In this view, the contact elements 25 contact contact lugs 26, which in turn are in contact with the conductor loop connections C. However, the contact lugs 26 can be omitted if a different geometry is selected, so that the conductor loop connections C can also be contacted directly with the contact elements 25. Furthermore, a shielding plate 27 formed on the rear of the shelf rail 3 can be seen, which shielding plate 27, analogous to the conductor loop L, also extends along the entire shelf rail 3.

[0101] The Figure 6shows the NFC reader 4 attached to a rail or sliding mechanism, wherein the sliding mechanism is partially pulled out of a shaft of the shelf rail 3 designed to accommodate it.

[0102] The following is with reference to the Figure 7-8 on the addressing of the shelf labels 2. The Figure 7-8 each show a state diagram, with time t on the abscissa and states Z of the system components on the ordinate

[0103] The Figure 7shows a temporal system in the time slot communication method, in which N (e.g. 256) time slots Z1 ... ZN with identical time slot duration DS (e.g. approx. 58 milliseconds) are available in a continuously repeating manner within a time slot cycle duration DC (e.g. 15 seconds). During the time slot cycle duration DC, the access point 6 switches between a transmit state T and an idle state R. The transmit state T is always assumed at the beginning of a time slot Z1 ... ZN and is maintained for a synchronization data signal duration DSD (or transmission time duration DSD) of the synchronization data signal SD in order to send the respective applicable time slot symbol ZS1, ZS2, ... ZSN with the respective synchronization data signal SD. The consecutive number of the respective time slot Z1 ... ZN in the order in which the time slots Z1 ... ZN occur is used as the respective time slot cycle symbol ZS1 ... ZSN.

[0104] In order to individually address one of the shelf labels 2A-2K and, if necessary, also supply it with data, address data AD and, if necessary, command data CD are embedded in the synchronization data signal SD of the relevant time slot Z1-ZN from the access point 6.

[0105] In the present embodiment, it is assumed that all NFC readers 4A-4C are wirelessly registered with the access point 6, i.e., can communicate with it using the time slot communication method. Each NFC reader 4A-4C initially detects the shelf labels 2A-2C, 2D-2F, and 2G-2K attached to its shelf rail 3 using an NFC polling loop and stores their individual shelf label NFC identifier in order to conduct NFC communication with them. Furthermore, each NFC reader 4A-4C stores which of the shelf labels 2A-2C, 2D-2F, and 2G-2K attached to its shelf rail 3 is assigned to which of the time slots Z1-ZN. This data structure of the assignment of the shelf labels 2A-2K, stored in the NFC reader 4A-4C, is also used by the server 5 to address the shelf labels 2A-2K individually, whereby several shelf labels 2A-2K can also be assigned to a single time slot Z1-ZN.

[0106] In the present case, let's assume that, for example, shelf labels 2A-2C are chronologically assigned to the first three time slots Z1-Z3. The entries in the data structure of NFC reader 4A now cause it to switch from its sleep state S to its active state A in time with the occurrence of the synchronization data signal SD of the first, second, and third time slots Z1, Z2, and Z3. It can be advantageous if the duration of the active state slightly exceeds the synchronization data signal duration DSD. In the active state, the relevant synchronization data signal SD is received, the NFC reader 4A determines its synchronism on the basis of the time slot symbol ZS1, ZS2, and ZS3 contained in the respective synchronization data structure SD and checks whether the shelf label 2A, 2B or 2C assigned to the respective time slot Z1, Z2 or Z3 is individually addressed by the server 5 using the address data AD.

[0107] In the present case, it is assumed that the shelf labels 2B and 2C are addressed, which in this case leads to a time-delayed NFC communication between the NFC reader 4A and the two shelf labels 2B and 2C, which is visualized by the arrows K. First, the NFC radio signal is generated and the first supply voltage VCC 1 is generated. This causes the respective shelf label 2B or 2C to leave its sleep state S and change to its active state A. The respective command data CD are then transferred to the addressed shelf label 2B and 2C and processed there.

[0108] The situation is analogous with the second NFC reader 4B, whose shelf labels 2D, 2E and 2F are assigned to the fourth to sixth time slots Z4, Z5 and Z6, whereby in the present case it is assumed that only the fourth and sixth shelf labels 2D and 2F are addressed.

[0109] The same applies analogously to the third NFC reader 4C, assuming that none of its shelf labels is addressed 2G-2K.

[0110] The unaddressed shelf labels 2A, 2E and 2G-2K therefore all remain in their energy-saving sleep state S within the visualized time slot cycle. The NFC readers 4A-4C also remain in their sleep state S in time slots Z1-ZN for which no shelf labels assigned to the respective time slot Z1-ZN are noted in the data structure.

[0111] Furthermore, it should be mentioned that the NFC readers 4A-4C can also be in active state A continuously or multiple times within the respective time slot Z1-ZN, for example if a response from the respective shelf label 2A-2K must be provided in the respective time slot or if additional data must be transmitted in this time slot with the affected shelf label 2A-2K. Data transmissions between the access point 6 and the respective NFC reader 4A-4C can also extend over multiple time slots Z1-ZN, which can lead to the active state A being present multiple times within the time slot cycle for the affected NFC reader 4A-4C.

[0112] The data transmission in the NFC sub-system can also take place in real time in the respective time slot when the address of a shelf label 2A-2K is recognized, i.e. not as in the Figure 7 illustrated with a time delay to the respective time slot.

[0113] In contrast to the previously discussed embodiment, it is now assumed according to a further (second) embodiment and with the help of the Figure 8visualizes that each of the NFC readers 4A-4C is assigned to a specific time slot Z1-ZN, such as the first NFC reader 4A to the first time slot Z1, the second NFC reader 4B to the third time slot Z3 and the third NFC reader 4C to the fourth time slot Z4. Only through this assignment of the NFC readers 4A-4C to the time slots does the assignment of the shelf labels 2A-2K to the respective slots Z1-ZN necessarily result. Here, the shelf labels 2A-2C are assigned to the first time slot Z1, the shelf labels 2D-2F to the third time slot Z3 and the shelf labels 2G-2K to the fourth time slot Z4.In order to address a shelf label 2A-2K in this system 1, the server 5 must know which NFC reader 4A-4C can wirelessly operate which shelf label 2A-2K in an NFC communication, in order to then indirectly address the shelf label 2A-2C, 2D-2F, or 2G-2K available there via addressing the respective NFC reader 4A-4C in the time slot communication method. This assignment is stored in a database of the server 5. The data structure of the NFC reader 4A-4C stores the time slot symbol ZS1-ZSN of the time slot Z1-ZN to which the respective NFC reader 4A-4C is assigned, and the addresses (shelf label identifiers) of the shelf labels 2A-2C, 2D-2F, or 2G-2K that can be addressed via it. The shelf label NFC identifiers for NFC communication in the NFC sub-system are also stored here.

[0114] The entries in the data structure of the first NFC reader 4A now cause it to switch from its sleep state S to its active state A in time with the occurrence of the synchronization data signal SD of the first time slot Z1, to determine its synchronism, and to check whether it is being addressed by the server 5 for the purpose of indirectly addressing shelf labels. If this is the case, a further check is performed to determine whether the server also addresses one of the shelf labels 2A-2C and, if this addressing exists, to process data traffic with this addressed shelf label in an NFC communication between the NFC reader 2A and this addressed shelf label. In the present case, it is assumed that only shelf labels 2A and 2B were addressed in the visualized time slot cycle, which leads to sequential NFC communication in the NFC subsystem with shelf labels 2A and 2B, which is visualized by the arrows K.

[0115] The same applies analogously to the second NFC reader 4B, which, during the period of occurrence of the synchronization data signal SD of the third time slot Z1, switches from its sleep state S to its active state A, determines its synchronism, and checks whether it is addressed by the server 5 for the purpose of indirectly addressing shelf labels. Here, it is assumed that only the fifth shelf label 2E is addressed, which leads to NFC communication with it in the NFC subsystem.

[0116] The situation is similar with the third NFC reader 4C, whose entries in its data structure cause it to switch from its sleep state S to its active state A in time with the occurrence of the synchronization data signal SD of the fourth time slot Z4, to determine its synchronism, and to check whether it is being addressed by the server 5 for the purpose of indirectly addressing shelf labels. If such an addressing occurs, it will address a sequence of one of its shelf labels 2G-2K. Here, it is assumed that only the eleventh shelf label 2K was addressed, which subsequently leads to NFC communication with it in the NFC subsystem.

[0117] As can be seen in the comparison of the state diagrams of the Figure 7 and 8As can be seen, the NFC readers 4A-4C need to be active less often in each time slot cycle when implemented according to the second embodiment, which makes the second embodiment prevail over the first embodiment in terms of energy efficiency when comparing the two embodiments.

[0118] Finally, it should be noted once again that the figures described in detail above are merely exemplary embodiments that can be modified in a variety of ways by those skilled in the art without departing from the scope of the invention, which is defined by the appended claims. For the sake of completeness, it should also be noted that the use of the indefinite articles "a" or "an" does not exclude the possibility that the relevant features may be present multiple times.

Claims

1. An electronic shelf label system (1), - wherein the system (1) comprises a server (5) adapted to individually address a plurality of shelf labels (2A-2K) to communicate data with them in an addressed manner, and - wherein the system (1) comprises at least one access point (6) which is connected to the server (5) and is designed for radio-technical communication of the data with the shelf labels (2A-2K), characterized in that the system comprises a near-field communication, abbreviated NFC, sub-system on a shelf rail (3) of a shelf (9), the NFC sub-system being characterized in such a way that - the shelf rail (3) comprises an NFC reader (4A-4C) which is designed for radio-based communication with the access point (6), and in that - at least one conductor loop (L) connected to the NFC reader (3), which is formed along the shelf rail (3) and is used for NFC communication with an NFC-capable shelf label (2A-2K), is provided, wherein - at least one NFC-capable shelf label (2A-2K) is attached to the shelf rail (3) corresponding to the conductor loop (L), and wherein - the NFC reader (4) is designed for NFC communication of the data with the shelf label (2A-2K) addressed by the server (5).

2. Electronic shelf label system (1) according to claim 1, wherein the access point (6) and the NFC reader (4A-4C) are designed for radio-based communication according to a time slot communication method, wherein in the time slot communication method a number of time slots (Z1-ZN) per time slot cycle are available for communication in a repeating sequence, preferably each time slot (Z1-ZN) is characterized by a unique time slot symbol (ZS1-ZSN).

3. Electronic shelf label system (1) according to claim 2, wherein - the NFC reader (4A-4C) stores a data structure which represents an assignment of a shelf label (2A-2K) attached to its shelf rail (3) to one of the time slots (Z1-ZN), and - wherein the NFC reader (4) is designed to check the time slot (Z1-ZN) to which a shelf label (2A-2K) is assigned according to the data structure as to whether the shelf label (2A-2K) attached to its shelf rail (3) is addressed by the server (5).

4. Electronic shelf label system (1) according to claim 3, wherein the NFC reader (4A-4C) is designed to transmit data between the addressed shelf label (2A-2K) and the access point (6) in the time slot (Z1-ZN) determined according to the data structure for the addressed shelf label (2A-2K) if a positive check result is present.

5. The electronic shelf label system (1) according to any one of claims 3-4, wherein - the NFC reader (4A-4C) comprises an energy-saving sleep state, in which there is no communication readiness for communication with the access point (6), and an active state, in which there is a communication readiness with the access point (6), and wherein - the NFC reader (4A-4C) is designed to switch from the sleep state to the active state in time for the occurrence of the time slot (Z1-ZN) to which a shelf label (2A-2K) is assigned according to the data structure.

6. The electronic shelf label system (1) according to any one of the preceding claims 3-5, wherein the server (5) stores in a database an individual shelf label identifier of each shelf label (2A-2K) and directly addresses the respective shelf label (2A-2K) based on the shelf label identifier.

7. Electronic shelf label system (1) according to claim 2, wherein - the NFC reader (4A-4C) is assigned to one of the time slots (Z1-ZN) and stores a data structure which represents the shelf labels (2A-2K) attached to the shelf rail (3) of the NFC reader (4A-4C), and wherein - the NFC reader (4A-4C) is designed to check the time slot (Z1-ZN) to which it is itself assigned as to whether the shelf label (2A-2K) attached to its shelf rail (3) is addressed by the server (5)8. The electronic shelf label system (1) according to claim 7, wherein the NFC reader (4A-4C) is designed to transmit data between the addressed shelf label (2A-2K) and the access point (6) if there is a positive check result in the time slot (Z1-ZN) intended for it.

9. The electronic shelf label system (1) according to any one of claims 7-8, wherein - the NFC reader (4A-4C) comprises an energy-saving sleep state, in which there is no communication readiness for communication with the access point (6), and an active state, in which there is a communication readiness with the access point (6), and wherein - the NFC reader (4A-4C) is designed to switch from the sleep state to the active state in time for the occurrence of the time slot (Z1-ZN) to which it itself is assigned.

10. The electronic shelf label system (1) according to any one of claims 7-9, wherein the server (5) stores in a database a link between a reader identifier of an NFC reader (4A-4C) and a shelf label identifier of the shelf label (2A-2K) which is installed on the shelf rail (3) of the NFC reader (4A-4C), and addresses a shelf label (2A-2K) indirectly via the link between the shelf label identifier of the shelf label (2A-2K) to be addressed and the reader identifier.

11. Electronic shelf label system (1) according to any one of the preceding claims, wherein the shelf label (2A-2K) comprises an energy-saving display unit (16), in particular based on electronic ink or electronic paper technology, etc.

12. Electronic shelf label system (1) according to one of the preceding claims, wherein the shelf label (2A-2K) comprises a rechargeable electrical energy storage device (12B) and is designed for contactless charging of the energy storage device (12B) by means of an NFC radio signal of the NFC reader (4A-4C).

13. A method of operating an electronic shelf label system (1) according to any one of claims 1 to 12, wherein according to the method the data is communicated between the NFC reader (4A-4C) and the shelf label (2A-2K) addressed by the server (5) by means of NFC communication.

14. Use of a near-field communication, abbreviated NFC, sub-system on a shelf rail (3) of a shelf (9) of an electronic shelf label system (1) according to any one of claims 1 to 12, wherein the NFC sub-system is used to communicate data in an NFC communication with a shelf label (2A-2K) addressed by a server (5) of the system (1).