METHOD FOR LOCATING AN ELECTRONIC SHELF LABEL

Abstract

The invention relates to a method for locating an electronic shelf label with an unknown location, in particular in the form of an electronic shelf label display, of an electronic shelf labelling system, wherein the system comprises a number of access points with known locations, which are positioned in different positions at a distance from a shelf, wherein the shelf has at least one shelf edge strip and wherein one of the shelf edge strips has at least one electronic shelf label that is designed such that it can be contactlessly supplied with power, and an electronic power supply device located on the shelf edge strip and designed for contactlessly supplying the at least one shelf label with power, wherein the method comprises the following method steps: determining the position of the electronic supply device in relation to the access points with known locations using an ultra-wide-band radio communication between the access points and the power supply device.

Claims

1. A method for locating an electronic shelf label (2) of unknown location, in particular realized as an electronic shelf label display, of an electronic shelf label system (1), the system (1) comprises: a number of access points (6) of known location, which are positioned at different positions, each at a distance from a shelving unit (9), the shelving unit (9) comprises at least one shelf edge strip (3), and one of the shelf edge strips (3) comprises at least one electronic shelf label (2), which is designed such that it can be supplied with energy contactlessly, and an electronic supply device (4) which is located on the shelf edge strip (3) and is designed for contactless energy supply of the at least one shelf label (2), wherein the method comprises the following method steps, namely: determining the position of the electronic supply device (4) in relation to the access points (6) of known location using ultra-wideband wireless communication between the access points (6) and the supply device (4).

2. The method according to claim 1, wherein the determination of the position of the electronic supply device (4) is based on determining the distance between it and each of the involved access points (6) using the respective ultra-wideband wireless communication.

3. The method according to claim 1, wherein the at least one electronic shelf label (2) installed on the shelving unit (9) is identified during energy supply thereof.

4. The method according to claim 2, wherein, during energy supply of the shelf label (2), the latter is identified by requesting its unique identifier (16A-16E).

5. The method according to claim 1, wherein, for contactless energy transmission, at least one first conductor loop (L1-L5) is used, which is formed on the shelf edge strip (3) and is connected by way of its two loop connectors (C1-C5) to the supply device (4) and is used for inductive coupling to a locally corresponding second conductor loop (12) of the shelf label (2).

6. The method according to claim 5, wherein, to determine the position of a shelf label (2) along the shelf edge strip (3), a plurality of first conductor loops (L1-L5) are used, which are positioned at different locations along the shelf edge strip (3).

7. The method according to claim 6, wherein the supply device (4) is used to carry out an individual energy supply at the location of the respective first conductor loop (L1-L5), if a shelf label (2) is positioned there.

8. The method according to claim 1, wherein an NFC interface (11, 18) is used for contactless energy supply and in particular identification both on the side of the shelf label (2) and on the side of the supply device (4).

9. The method according to claim 1, wherein the electronic shelf label (2) realized as a shelf label display comprises an energy-saving display unit (13), in particular based on electronic ink or electronic paper technology etc., with which static image information is displayed with the aid of the display unit (13) even during a time period without energy supply.

10. The method according to claim 1, wherein position-relevant results of the ultra-wideband wireless communication are transmitted in a wired or wireless manner either from the supply device (4) or from the involved access point (6) to a data processing device (5) to determine the location of the supply device (4).

11. The method according to claim 9, wherein the identity of a shelf label (2) identified during the energy supply thereof by the supply device (4) is communicated to the said data processing device (5), and the location of the relevant shelf label (2) relative to the location of the relevant supply device (4) is at least narrowed down at the data processing device (5).

12. The method according to claim 1, wherein the position of a movable object (7) can be at least narrowed down by ultra-wideband wireless communication between it and at least one of the supply devices (4).

13. The method according to claim 12. wherein, by repeatedly narrowing down the position of the movable object (7), a path of movement of the object (7) is determined.

14. The method according to claim 12, wherein information corresponding to the position of the object (7) is displayed either via a screen of the object (7) or via a shelf label (2) which is positioned in the vicinity thereof and is realized, as a shelf label display.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0035] The invention is explained once more in detail in the following with reference to the attached figures on the basis of exemplary embodiments, to which the invention is not restricted, however. In the various figures, identical components are provided with identical reference numbers. In the figures:

[0036] FIG. 1 schematically shows an electronic shelf label system according to the invention;

[0037] FIG. 2 schematically shows a block diagram of a shelf label display;

[0038] FIG. 3 schematically shows a block diagram of an “intelligent” shelf edge strip with a supply device;

[0039] FIG. 4 schematically shows the shelf edge strip in a front view;

[0040] FIG. 5A-5B schematically shows an arrangement of such shelf edge strips, changing over time;

[0041] FIG. 6 schematically shows a printed circuit board of the “intelligent” shelf edge strip;

[0042] FIG. 7 schematically shows the printed circuit board according to FIG. 6 integrated in the shelf edge strip;

[0043] FIG. 8 schematically shows the “intelligent” shelf edge strip with direct integration of a conductor loop.

DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

[0044] FIG. 1 shows a part of a shelf label system 1 in a business premises, which comprises a number of identically constructed, namely NFC-enabled, electronic shelf label displays 2, which are fastened to four “intelligent” shelf edge strips 3 positioned next to one another (in a row along the width of a shelving unit 9), the shelf edge strips 3 being visible substantially in a front view. Each shelf edge strip 3 has an electronic supply device 4 for contactless energy supply of the shelf label displays 2 and for contactless communication with a shelf label display 2 supplied with energy, this being realized with the aid of NFC technology. Also illustrated is a data processing device, which is realized with the aid of a server 5, which is connected in a wired manner to four identically constructed access points 6, the access points being positioned at different locations within a business premises, and the server 5 knowing these locations.

[0045] The supply devices 4 illustrated are in wireless contact with e.g. the access point 6 on the far left, to which they are logically assigned, via first wireless signals F1. The image contents of the shelf label displays 2 within the entire business premises can thus be changed from the server 5, and where necessary associated status information can also be requested from the shelf label displays 2 and transmitted to the server 5.

[0046] The shelf label displays 2 of other shelving units 9 (not illustrated here) can likewise be logically assigned in groups to the other access point 6 illustrated, so that in each case one access point 6 wirelessly supplies a subset of all the shelf label displays 2 of the business premises.

[0047] Each access point 6 has two wireless modules 6A and 6B, wherein both of these are only indicated schematically in the respective access point 6, separated from each other by dashed lines.

[0048] The first wireless module 6A communicates by means of the first wireless signal F1 and is used to define the image contents. To do this, it uses ultra-wideband wireless technology (referred to in the technical jargon as UWB technology, UWB standing for “ultra wideband”), and its electronics as well as its antenna configuration (neither illustrated in detail) are designed to implement this technology.

[0049] The second wireless module 6B is designed as a supply transmitter and supplies the supply devices 4 with energy selectively by sending directed second wireless signals F2. To this end, the second wireless module 6B has, in addition to its electronics, a number of antennas, with the aid of which the direction of the energy transmission (ultimately the propagation of the second wireless signal F2, which is sent at e.g. 5 watts) can be set relatively precisely, so that the energy to be transmitted arrives exactly at a selected supply device 4. This energy transmission technology is known by the term “power over WiFi”, and the electronics and the antenna configuration of the second wireless module 6B are designed accordingly.

[0050] The “power over WiFi” functionality, that is to say, the second wireless module 6B, can be integrated in the access point 6 or realized as a separate assembly/separate device, which is e.g. coupled for control to the first wireless module 6A.

[0051] Each of the shelf edge strips 3 is mounted on the front edge of an individual shelf 8. The four shelves 8 illustrated all belong to the shelving unit 9, which is indicated only schematically. Different products can be presented on the shelves 8 but are not illustrated in the present case.

[0052] In the visualization of FIG. 1, the reference numerals 2 and 4 are entered only for the top shelf edge strip configuration, which shows four shelf edge strips 3, and have largely been omitted from the three configurations of the shelf edge strips 3 below for reasons of simplicity.

[0053] Furthermore, FIG. 1 shows a shopping trolley 7, which is being moved past the shelving unit 9 to the left. The shopping trolley 7 has a mobile wireless unit 21, which is designed for ultra-wideband wireless communication. The wireless unit 21 has e.g. battery-operated wireless electronics and an antenna configuration connected thereto (neither illustrated) and establishes a UWB wireless connection to the supply devices 4 within its range with the aid of the first wireless signals F1, on the basis of which the supply devices 4 can determine the distance from the wireless unit 21.

[0054] During normal operation, which is referred to as the normal mode of the system 1, all the shelf label displays 2 are assigned wirelessly to the access point 6 on the far left, as mentioned, and the changing of the image contents is controlled with the aid of the first wireless signals F1 via this access point 6 arranged on the far left.

[0055] The situation in which the shelf label displays 2 are sought is different by contrast. In this case, which is referred to as the locating mode of the system 1, multiple, in the present case all four, access points 6 are used, and the distance between the respective supply device 4 and the respective access point 6 is determined during communication with, for example, the supply device 4 installed in the top left corner with the aid of the first wireless signals F1, which each of the access points 6 now exchanges with the supply device 4 in UWB wireless communication. The distances thus determined are transmitted to the server 5 via a wired network (LAN), and the server 5 determines the spatial position of the affected supply device 4 with knowledge of the absolute positions of the four access points 6.

[0056] A block diagram of the shelf label display 2 is explained below FIG. 2.

[0057] The block diagram according to FIG. 2 shows a first NFC interface with its coupling coil 12; NFC stands for “Near Field Communication”. With the aid of the coupling coil 12, an inductive coupling is established with another NFC-enabled device, in the present case the supply device 4, specifically with the conductor loops L1 to L5 formed on the shelf edge strip 3 (see FIG. 3), when the coupling coil 12 is brought correspondingly close to one of the conductor loops L1-L5, which is the case when the shelf label display 2 is attached to the shelf edge strips 3. During the inductive coupling, a first supply voltage VCC1 is generated relative to a first reference potential GND1 with the aid of the first NFC interface 11 for the operation of the entire shelf label display 2, which activates the electronics of the shelf label display 2, so that contactless bidirectional communication of data D can also be carried out via its first NFC interface 11. A constituent of these electronics is also an NFC controller, which provides the entire NFC functionality, but is not shown here in detail, but is integrated in the first NFC interface 11.

[0058] The block diagram also shows a display unit 13, which is connected to the first NFC interface 11 and is divided into a screen controller realized as an electronic paper display controller 14 and a screen realized as an electronic paper display screen 15 which is connected thereto and can be controlled therewith. With the aid of the controller 14, the data D received is interpreted, the image content of the screen 15 is changed accordingly, where necessary, or else status information in the form of data D is output to the supply device 4 via the NFC interface 11.

[0059] A block diagram of the shelf edge strip 3 according to Figure particularly also the supply device 4, is discussed below using FIG. 3.

[0060] The supply device 4 illustrated in FIG. 3 is designed both for its own contactless supply with energy and also for contactlessly supplying the shelf label displays 2 with energy. For its own supply, it has a supply receiver 23 which is suitable for receiving the second wireless signal F2 and is equipped with an antenna configuration 24 (which can have multiple antennas) and electronics, which are designed to receive the second wireless signal F2 and to store the energy transmitted therewith in an internal electrical energy storage device 25 (chargeable battery, rechargeable battery) and to generate the second supply voltage VCC2 relative to a second reference potential GND2.

[0061] During operation, the supply device 4 can query or monitor the state of charge of the energy storage device 25, for example with the aid of its control unit 20. As soon as the state of charge falls below a certain level, the control unit 20 can request a (re)charge with the aid of the first wireless signal 51. This request is received by the access point 6 to which the supply device 4 is logically (wirelessly) assigned. Since the exact geographical position (the three-dimensional coordinates) of each of the supply devices 4 and their unique identifier is known in the system 1 (e.g. the server 5), because e.g. the position was determined previously with the aid of the locating mode, the affected access point 6 can send the second wireless signal F2 in a precisely directed manner towards the position of the respective supply device 4 requesting charging. The second wireless signal F2 is received there, and the energy transmitted with the aid thereof is used to charge the internal energy storage device 25 there.

[0062] In the visualization of FIG. 3, a printed circuit board 17 is also indicated, which was omitted from the diagram in FIG. 1 for reasons of clarity. The printed circuit board 17 supports five conductor loops L1 to L5, wherein in the present case these are designed with multiple loops or windings, which is indicated in each case with the symbol for an electric coil. The printed circuit board 17 is integrated into the relatively flat structure of the shelf edge strip 3. The supply device 4 can be soldered to said printed circuit board 17 or connected via cables or plug connectors, so that the conductor loops L1 to L5 are electrically contacted via their loop connectors C1 to C5.

[0063] Corresponding to the position of the respective conductor loop L1 to L5, the shelf label display 2 respectively positioned there is also illustrated and indicated. Here, the electrical connection of the loop connectors C1 to C5 to the supply device 4, but in particular to the electronics of its (second) NFC interface 18, is also specifically illustrated. If an inductive coupling with the first NFC interface 11 of the shelf label display 2 is present, the second NFC interface 18 is designed for the contactless transmission of electrical energy to the shelf label display 2 and for bidirectional contactless communication of data with the shelf label display 2 activated by energy transmission. The conductor loops L1 to L5 are multiplexed with the aid of the NFC interface 18 which is specifically designed to do this, therefore only one of the conductor loops L1 to L5 is ever in use. An “analogue switch” known in electronics can be used for this.

[0064] The supply device 4 furthermore has an access point communication interface 19, which is designed for wireless communication with the access point 6 illustrated in FIG. 1. It has an antenna configuration 19A, which can also be constructed from multi single antennas, and electronics, with which the first wireless signals F1 can be received and sent. In particular, the access point communication interface 19 is designed for ultra-wideband wireless communication.

[0065] The control unit 20 is used to control the internal processes, the energy supply to the shelf label display 2 and communication with the shelf label display 2, and communication with the access point 6. It is realized with the aid of a microcontroller, which is connected to the second NFC interface 18 and the access point communication interface 19 as well as the supply receiver 23 via a bidirectional data bus.

[0066] In FIG. 4, the shelf edge strip 3 illustrated in the top left corner in the shelving unit 9 is illustrated in a more detailed view. Only the left-hand edge of the printed circuit board 17 supporting the conductor loops L1 to L5 is visible, to avoid overloading the visualization. In this visualization, only the first loop connectors C1 connected to the supply device 4 are illustrated. However, the same applies correspondingly to the remaining four loop connectors C1 to C5, the direct connection of which to the supply device 4 has been omitted for reasons of clarity. It is furthermore illustrated symbolically that each of the shelf label displays 2 contains the uniquely identifying identifier data 16A to 165, which are stored permanently and immutably in an internal memory.

[0067] Since the measures with which the position of the supply device 4 (e.g. located in the top left of the shelving unit 9) is determined have been already explained above, the locating of the five shelf label displays 2 fastened to this shelf edge strip 3 is now explained. In the aforementioned locating mode, the supply device 4 then activates the five shelf label displays 2 sequentially. To this end, an inductive coupling is first established via the two NFC interfaces 11 and 18 to the shelf label displays 2 positioned on the far right with the aid of the conductor loop L1 there (on the far right) and in the process energy is transmitted to them so that the electronics of the shelf label display 2 are activated. The unique first identifier data 16A is then retrieved with the aid of the coupled NFC interfaces 11 and 18 and stored in the supply device 4. Then the energy supply, that is to say, the coupling, is terminated, and the shelf label display 2 is deactivated. This process is then carried out step by step for each of the other conductor loops L2 to L5 until all the unique identifier data 16A to 165 are present in the supply device 4. The unique identifier data 16A-16E thus determined are then output via the access point communication interface 19 to the access point 6 responsible for the relevant supply device 4, which in the present case is the access point 6 illustrated on the far left in FIG. 1. From there, these identifier data 16A to 165 are forwarded to the server 5, which has already determined the absolute position of the supply device 4 located in the top left corner and which is also informed of the dimensions of the shelf edge strip 3 and the positions or coverage zones of the respective conductor loops L1 to L5 along the shelf edge strip 3. From this information, in particular from the relationship between the respective conductor loop L2 to L5 (e.g. the order in which they are used) and the identifier data 16A to 16E obtained via the respective conductor loop L2-L5, the server 5 then determines the respective shelf label display position 10A to 10E for each shelf label display 2 along the shelf edge strip 3, e.g. measured from a known reference position 16, e.g. the known position of the supply device 4, or else from the right or left edge of the shelf edge strip 3.

[0068] If the orientation of the shelf edge strip 3 in space is clear to the server 5, which can be determined e.g. by determining and thus also knowing some or else all positions of the supply devices 4 of the shelving unit 9, the clear position of each of the shelf label displays 2 in space can also be determined by the server 5.

[0069] A use scenario for the method for locating the electronic shelf label displays 2 is described below with the aid of FIGS. 5A and 5B.

[0070] It can be assumed here that a starting configuration of the shelving units 9 is illustrated in FIG. 5A, and a final configuration of the shelving units 9 is illustrated in FIG. 5B, the two FIGS. 5A and 5B being separated from each other with the aid of a dividing line. The shelving units 9 illustrated are illustrated as viewed from above, and two adjacent shelf edge strips 3 are illustrated per shelving unit 9 in each case. The structure of shelf label displays 2 and supply device 4 illustrated in the top left corner is replicated over the two columns and four rows of the shelving unit 9 illustrated, and therefore only the top left shelf edge strip 3 has been provided with reference numerals, for reasons of clarity. FIGS. 5A and 5B additionally show three access points 6, which are installed on the ceiling of a business premises in which the shelving units 9 are erected, at positions between the shelving units 9.

[0071] It can be seen that the two bottom right shelving unit positions in FIG. 5A are not occupied by shelving units 9. Proceeding from the starting configuration according to FIG. 5A, in the transition to the final configuration according to FIG. 5B, two of the shelving units 9 are moved according to the arrows 22A and 22B to the free shelving unit positions in the starting configuration.

[0072] In order to locate the shelf label displays 2 now, locating mode is activated, and the positions of the individual supply devices are first determined with the aid of the UWB wireless communication as explained. For the supply devices 4 for which only a slight or no change in location results, the method is terminated here already, because it is assumed that the associated shelf edge strips 3 have not been subjected to any change in location.

[0073] For the supply devices 4 which are now installed on the shelving units 9 which have changed position according to the arrows 22A and 22B and therefore for which a change in position going beyond a threshold value has been established, in a second step, the shelf label displays 2 installed there are identified during individual energy supply thereto, and the identifier data 16A to 16E thus obtained are transmitted to the server 5 for defining the respective position of each shelf label display 2. The system 1 then reassumes normal mode.

[0074] The supply devices 4 located at their new positions then simply log in wirelessly to the closest access point 6, because they are already known in the system 1 and have been registered previously, and are available there as usual. A re-registration at the closest access point 6 can also take place.

[0075] However, it should be mentioned at this point that the previously explained termination of the method for the supply devices 4 which have not changed position does not necessarily have to take place. The method can also be executed as explained above for these supply devices 4, that is to say, applied to all the supply devices 4 and the shelf label displays 2 supplied thereby, which ultimately leads to the taking of a full inventory of the shelf label displays 2. This may make sense all the positions are to be determined deliberately or a test is carried out as to whether individual shelf label displays 2 have been removed from the shelving units involved or the shelf edge strips 3 there (although they have not been moved) or moved to other locations or displaced along the shelf edge strips 3 etc.

[0076] With the new positions thus determined, the digital three-dimensional map of the shelf label displays 2 is adapted to the reality now present in the business premises or an existing three-dimensional map is verified with the aid of the server 5.

[0077] With the aid of the access point communication interface 19 designed for ultra-wideband wireless communication, however, movable objects, which move past or stay in front of the shelving unit 9 like the shopping trolley 7 illustrated in FIG. 1, can also be tracked or identified with the aid of the first wireless signals F1. After it has successfully been detected that such a shopping trolley 7 is in a predefined region in front of e.g. the second shelf edge strip 3 from the left on the bottom shelves, specific information relating to the products presented there can be displayed via the shelf label displays 2 fastened to this shelf edge strip 3 with the aid of the supply device 4 installed there.

[0078] According to a further exemplary embodiment, the access point 6 can also be designed such that the first wireless module 6A with its UWB technology is only used for distance determination and, together with other access points 6, for position determination. The second wireless module 6B can be configured and used for energy transmission, as explained. In addition to this, a third wireless module (not illustrated) can also be realized, which is designed for communication of display contents, commands or status messages according to e.g. a proprietary time slot communication method mentioned in the general part of the description or a standardized communication method (ZigBee, Bluetooth, . . . ). Accordingly, the electronic supply device 4 also has, instead of the two wireless interfaces 19, 23 illustrated in FIG. 3, an additional wireless interface for communication with the third wireless module, the access point 6.

[0079] A realization of the printed circuit board 17 and the shelf edge strip 3 is also discussed in the following.

[0080] FIG. 6 shows by way of example such a printed circuit board 17, which has conductor tracks on both sides. For reasons of clarity, only three of the five conductor loops L1-L5 are illustrated. The conductor loops L1, L2 and t5, which have a large area, can be seen on the front. On the rear, the conductor tracks LB2-LB5, running close together, of the respective loop connectors C2 and C5 can be seen, which run along the longitudinal extent of the Printed circuit board 17. The loop connectors Cl run on the front side. The loop connectors C1-C5 are all connected to the supply device 4. There are vias DK2 and DK5 from the front to the rear in the places where the loop connectors C2 and C5 end at the conductor loops L2 and L5, so that the conductor loops L2 and L5 are electrically conductively connected to their loop connectors C2 and C5. The same applies correspondingly to the conductor loops L3 and L4, their loop connectors C3 and C4, their conductor tracks LB3 and LB4, and the two vias DK3 and DK4, which are not shown. The supply device 4 indicated on the printed circuit board 17 can be attached, for example, to the rear of the printed circuit board 17. The electronic components of its electronics can also be soldered directly to the printed circuit board 17.

[0081] FIG. 7 finally shows a possibility of mechanically integrating the printed circuit board 17 in the shelf edge strip 3. The printed circuit board 17 forms a part of the wall of a receiving slot, which is used to receive a number of shelf label displays 2. At the point where the printed circuit board 17 is to be attached, the receiving slot has a depression which corresponds to the thickness of the printed circuit board 17 and into which the printed circuit board 17 is inserted so that its front runs substantially planar with the rest of the wall of the receiving slot. On the front of the shelf edge strip 3, an upper guide strip 26 is formed on the upper end and a lower guide strip 27 is formed on the lower end. These guide strips 26 and 27 can be bent upwards and downwards until the shelf label display 2 can latch in. In addition, the shelf label display 2 can be displaced unhindered along the shelf edge strip 3 and positioned completely freely. The accommodation of the supply device 4 on the rear of the printed circuit board 17 is advantageous if it should be possible to displace the shelf label displays 2 along the front of the shelf edge strip 3 unhindered, as is possible in the present case. For this case, the depression in the receiving slot must be adapted accordingly so that there is also space for the electronic components of the supply device 4.

[0082] FIG. 8 shows the shelf edge strip 3 in a cross-sectional illustration, with a conductor loop mount 28 on its rear side, the conductor loop mount 28 being manufactured directly from the material of the shelf edge strip 3 (that is to say, from the plastic). The conductor loop mount 28 has a gap-like depression 29, into which a wire of the conductor loop L1 is inserted in an immovable manner. The gap-like depression 29 is flanked by two walls 30, which are dimensioned in such a manner that with their aid, a snap mechanism is realized, which fixes the wire in its intended position. A band- or strip-like material 31 (material band or strip) is inserted into the gap-like depression 29 for this purpose, which on the one hand presses the wire of the conductor loop L1 against the base of the depression 29 and on the other hand supports itself on a lug- or hook-like end of the outer wall 30 in each case or latches there.

[0083] However the integration of the conductor loop(s) L1 (to L5) into the shelf edge strip 3 or the fastening of the conductor loop(s) Ll (to L5) to the shelf edge strip 3 is realized, it has furthermore proven particularly advantageous that the electronic supply device 4 is integrated into the shelf edge strip or is fastened to the same. Thus, a shelf edge strip with individual electronic energy supply can be realized. In this case, the supply device 4 can e.g. also be formed directly on the printed circuit board 17 or connected to the same as a module or mechanically coupled to the shelf edge strip 3 as a module and electrically conductively connected to the conductor loop L1 (to L5) of the shelf edge strip 3. As a result, the shelf edge strip 3 as a whole, including its supply device 4, can be taken out and recommissioned at a different location without problem.

[0084] Neither FIG. 7 nor FIG. 8 shows a fastening mechanism for the shelf edge strip 3, which allows the fastening of the shelf edge strip 3 on a different structure, such as e.g. a shelf 8, because this detail does not relate to the invention and can be realized in a wide range of ways that are known to the person skilled in the art.

[0085] Finally, it is once more pointed out that the figures previously described. in detail are only concerned with exemplary embodiments, which can be modified in many different ways by the person skilled in the art, without departing from the scope of the invention. For the sake of completeness, it is also pointed out that the use of the indefinite article “a” or “an” does not mean that the relevant features cannot also be present multiple times.