Electronic display device and method for operating the electronic display device

Abstract

An electronic display device, in particular an electronic label, more particular an electronic shelf label, which comprises: - an electrophoretic display to display a content visualizing image that is represented by first image data, and - a control unite that has access to the first image data and that is configured to drive the electrophoretic display according to the first image data, characterized in that the control unit is configured: - to drive the electrophoretic display to display a white or a single-color, in particular content-free, image when entering into a period of non-usage, and, - upon an occurrence of an activation event that terminates the period of non-usage, to drive the electrophoretic display to display the content visualizing image.

Description

[0001] TP0563

[0002] Title

[0003] Electronic display device and method for operating the electronic display device.

[0004] Description

[0005] Technical Field

[0006] The invention relates to an electronic display device and a method for operating such an electronic display device and a computer implemented method for operating the electronic display device and a method for producing an electronic display device.

[0007] Background

[0008] Nowadays electronic display devices are commonly used at retailers to display product and / or price information at for example shelves, sales stands, etc. In such an application the electronic display devices are termed electronic shelf label displays, commonly abbreviated as ESLs. Other applications for the electronic display devices are found in the field of electronic room identification signs. Such electronic room identification signs are used to display information regarding the name of the room, the activity assigned to the room or even the occupation period of the room etc. Further applications of ESLs may be found in warehouses or wholesale.

[0009] Such electronic display devices use electrophoretic displays, which are based on the so-called electrophoresis principle that refers to the movement of suspended charged particles in a suspension fluid under the influence of a direct current (DC) electric field. Once the information to be displayed is set at the electrophoretic display, the electrophoretic display maintains the visibility of the displayed information even without power supply.

[0010] However, after longer periods without any update of the displayed information electrophoretic displays tend to show undesired visual effects, which may lead to image sticking, sometimes termed image retention or ghosting, which is a phenomenon where a faint outline of a previously displayed image remains visible on a screen when the image is changed. This problem is already identified in US 2011 / 0234557 Al, but the measures disclosed to overcome this problem are very complex.

[0011] The invention thus has the object of avoiding the difficulties elaborated above and to provide an improved method for operation an electronic display device and an improved electronic display device.

[0012] Summary of the Invention

[0013] This object is solved by means of an electronic display device according to claim 1. The subject matter of the invention is thus an electronic display device, in particular an electronic label, more particular an electronic shelf label, which comprises an electrophoretic display to display a content visualizing image that is represented by first image data, and a control unite that has access to the first image data and that is configured to drive the electrophoretic display according to the first image data, characterized in that the control unit is configured to drive the electrophoretic display to display a white or a single-color, in particular content-free, image when entering into a period of non-usage, and, upon an occurrence of an activation event that terminates the period of non-usage, to drive the electrophoretic display to display the content visualizing image.

[0014] The object of the invention is also solved by a method for operating an electronic display device according to claim 9. The subject matter of the invention is thus a method for operating an electronic display device, in particular an electronic label, more particular an electronic shelf label, the method is performed by the electronic display device that comprises an electrophoretic display and a control unit that has access to first image data, which first image data represent a content visualizing image, the method comprises the following steps, namely: driving the electrophoretic display by the control unit according to the first image data to display the content visualizing image, characterized in that the method comprise the steps of driving the electrophoretic display by the control unit to display a white or a single color, in particular content-free, image when entering into a period of non-usage, and, upon an occurrence of an activation event that terminates the period of non-usage, driving the electrophoretic display by the control unit to display the content visualizing image. The object of the invention is also solved by a method for producing an electronic display device according to claim 18. The subject matter of the invention is thus a method of producing an electronic display device, in particular an electronic label, more particular an electronic shelf label, wherein the method comprises the steps of manufacturing and / or testing the electronic display device according to the invention, and, thereafter, driving the electrophoretic display by the control unit to display a white or a single color, in particular content-free, image when entering into the period of nonusage.

[0015] The object of the invention is also solved by a computer implemented method for operating an electronic display device according to claim 19. The subject matter of the invention is thus a computer implemented method for operating an electronic display device, in particular an electronic label, more particular an electronic shelf label, comprising an electrophoretic display , wherein the method comprises the following steps, namely generating driving data for driving the electrophoretic display according to first image data, wherein the first image data represent a content visualizing image, characterized in that the method comprise the steps of: generating driving data for driving the electrophoretic display to display a white or a single color, in particular content-free, image when entering into a period of non-usage, and, upon an occurrence of an activation event that terminates the period of non-usage, generating driving data for driving the electrophoretic display to display the content visualizing image. The control unit is configured to generate the driving data and to drive the electrophoretic display by the driving data.

[0016] The electronic display device uses the electrophoretic display, which - as mentioned - is based on the so-called electrophoresis principle that refers to the movement of suspended charged particles in a suspension fluid under the influence of a direct current (DC) electric field. In case of a black and white electrophoretic display only charged black particles and charged white particles are used. As usual, black and white are not referred to as colors in this application. In case of a color-enabled electrophoretic display also charged colored particles are used. The realization of the electrophoretic display (including its driver electronics) in its various embodiments like black and white or even color-enabled and the realization of the control unite (its circuity logic and / or programing) to use the image data to drive the electrophoretic display to display the image that is represented by image data is well known to the person skilled in the art. The term electrophoretic display shall include at least conventional (non-encapsulated) electrophoretic displays as well as micro encapsulated electrophoretic displays, for both the technical jargon is "electronic paper".

[0017] Now, the measures according to the in invention are based on an insight of the applicant that the undesired visual effects that lead to image sticking are mainly attributed to the black particles, which seem to tend to stick more than the white particles. Further to this, once the black particles stick, their visual impact is more significant in terms of visual recognizability, when compare with white particles. The higher sticking tendency of black particles in comparison to white particles is assumed to be related to the size of the black particles that are smaller than the white particles.

[0018] Based on this insight the applicant invented the electronic display device and the method of operation the electronic display device, wherein the displaying of an image that contains black is avoided during a period of nonusage. The measures according to the invention now significantly reduces the risk of undesired visual effects like image sticking that otherwise would be caused by the black particles and established during the period of non-usage. A significant improvement over known measures that deal with the avoidance of sticking images is the fact that the realization of the electrophoretic display as such and the realization of the driver electronics to drive the electrophoretic display remain unchanged over prior art. The control unite and the method only require a modification to distinguish between the period of non-usage and a normal operation period. During the normal operation period for example product related information is displayed by an electronic shelf label or room related information is displayed by an electronic room label. In both exemplary embodiments the information is displayed by the electrophoretic display, wherein the displayed content may by intentionally changed over time to update the displayed information and keep it up to date. Typically, black particles, white particles, and if available also colored particles are used therefore. In contrast thereto during the period of non- usage, the control unit secures that a content free image is shown by the electrophoretic display. The content free image avoids the use of black particles or in other words it is free of black particles or black pixels, respectively.

[0019] In the present context "content-free" shall mean an image that does not convey any information that can be used to unambiguously identify the respective electronic display device or to enable its individual unambiguous use either by a human or by a machine. However, knowing upfront how the content-free image looks like (because it is a white image or a single-color image) enables the human or the machine to identify that the respective electronic display device rests in the period of non-usage. The identification of the resting in the period of non-usage may be used by the human or the machine to initiate the activation event. However, the triggering of the activation event may also be based on other circumstances, in particular without any upfront identification of the resting in the period of non-usage.

[0020] The electronic display device may be realized as an electronic display sign or electronic display label, which is configured to be located at a shelf, in particular at the font edge of the shelf, where it realizes an electronic shelf display, typically abbreviated as ESL. Such an ESL may also be configured to be attached to a holder so that it can be placed on a table on which goods are presented or so that it can be placed in a vitrine or fridge. The electronic display device may also be used as an electronic signage of rooms, for example in conference center or hotel, where the electronic display device is sometimes termed electronic room display device. Further to this the electronic display device may also be used as an electronic signage in logistics to provide information related to products that are stored for example in a storage location etc. In such applications the electronic display device is sometimes termed digital signage.

[0021] Dependent on the actual application of the electronic display device it may be configured for radio-based communication with another device, in particular with an access point or with an NFC-device. Alternative, the electronic display device may be configured for line-base communication with another device.

[0022] The electronic display device may comprise a battery to provide electrical power for its operation. Alternative, the electronic display device may by configured to be supplied with electrical power from an external power supply. Typically connectors and / or cables are provided to archive this, but also a configuration to allow the supply of electrical power by means of power over Wi-Fi may be implemented.

[0023] Further, particularly advantageous designs and further developments of the invention follow from the dependent claims as well as from the following description.

[0024] The electrophoretic display comprises a screen that has a visualization area or zone. The visualization area is the visible part of the screen and is used to show the entire image. Given the fact that the various content visualizing images typically do not occupy the entire visualization area of the electrophoretic display, which means that only a fraction of the visualization area may be occupied by the actually shown image, it would be possible to limit the appearance of the white or single-color image only to that area that is used to display content conveyed by the content visualizing image. However, according to a preferred embodiment the control unit is configured to drive the electrophoretic display to display the white or singlecolor image throughout its entire visualization area. In terms of the method, it is provided that method comprises the step of driving the electrophoretic display by the control unit to display the white or single-color image throughout its entire visualization area. This secures that the entire visualization area is protected against image sticking while the period of nonusage is pending.

[0025] According to a first embodiment the control unit is configured to generate second image data when entering the period of non-usage, wherein the second image data represent the white or the single-color image. In terms of the method, it is provided that the method comprises the step of generating second image data by the control unit when entering the period of non-usage, wherein the second image data represent the white or the singlecolor image. In this embodiment the second image data are generated on the fly when needed by the control unit. This may save the otherwise required memory space to per-store the second image data.

[0026] However, to reduce the required modification of the control unite or its functioning, respectively, the preferred embodiment provides that the electronic display device comprises a memory stage to store the second image data, which represent the white image or the singe color image, and the control unit is configured to make available the second image data for the electrophoretic display when entering the period of non-usage. In terms of the method, it is provided that the method comprises the steps of storing the second image data by the memory stage of the electronic display device and making available the second image data by the control unit for the electrophoretic display when entering into the period of non-usage. This requires pre-storing the second image data, which can easily be achieved during production of the electronic display device. Furthermore, this feature allows to apply a well-known page-switch operation of the control unit, which is commonly used to switch between a first memory page (first addressable memory space of the memory stage) and a second memory page (second addressable memory space of the memory stage). As a result of the page- switch operation either the first image or the second image is displayed by the electrophoretic display. Here it is used to activate the display of the white or a single-color image. Again, it is emphasized that no modification of the basic operational features of the electrophoretic display device, in particular the control unit and the electrophoretic display, is required because the page- switch operation is typically already implemented. But in this application, the page-switch operation is used for a different purpose than displaying two different content visualizing images.

[0027] Access to the first image data may be provided by a host computer in a radio-based of line-based communication with the electronic display device. This may be done on demand when the control unit demands to receive the respective first image data, in particular upon the occurrence of the activation event. However, in a preferred scenario the first image data are made available upfront of the actual moment of demand, which means they were received by the electronic display device earlier and stored by the electronic display device. Further to this and independent of the aforementioned embodiments it is further provided that the memory stage stores the first image data, and the control unit is configured to make available the first image data for the electrophoretic display as a consequence of the occurrence of the activation event. In terms of the method, it is provided that the method comprises the steps of storing the first image data by the memory stage and making available the first image data by the control unit for the electrophoretic display as a consequence of the occurrence of the activation event. To be compete, the control unit may have access to a first memory stage and to a second memory stage, wherein the two memory stages are different. In this configuration a ROM (Read Only Memory) may be used to store the second image data that represent the white or single-color image as the second image data will never be changed. In contrast thereto the first image data that represent the content visualizing image will undergo some changes in time and will therefore be stored in an EEPROM (Electrically Erasable Programmable Read Only Memory). However, the first memory stage may also realize the second memory stage, meaning that only one memory stage exists where the first image data and the second image data are stored. As the first image data will undergo changes, the memory stage will be realized as EEPROM (Electrically Erasable Programmable Read Only Memory). Further to this, the first and / or second memory stage may be realized separate from the control unite or integrated into the control unit.

[0028] Hence in a preferred embodiment the first image data and the second image data are already stored in the respective memory stage before the first image data and the second image data are actually used (accessed by the control unit), and the control unite only decides which of the respective image data (the first image data / the second image data) are accessed and used by the electrophoretic display to visualize the image represented by the respective first image data or second image data.

[0029] According to a further aspect, the control unit is configured to identify a decommission event as an indicator of the entering into the period of non-usage. In terms of the method, it is provided that the method comprises the step of identifying by the control unit a decommission event as an indicator of the entering into the period of non-usage. The decommission event is a clear and unambiguous event that leads to a relative long-lasting period of non-usage of the electrophoretic display device. Prior to the present invention the electrophoretic display device simply maintained the displaying of the last depicted content visualizing image during the period of non-usage or it was set to display a bar code during the period of non-usage to identify the respective electronic display device unambiguously for later usage. Now, this is advantageously avoided during the period of non-usage. In practice the de-commission event can be any of the following events: - a finalization of a production or manufacturing process of the electrophoretic display device, for example when the electronic display device is first time ever electrically powered. This can be identified by the control unit by checking a flag in its memory or processing registers, respectively, or by receiving data signal or an analogous signal at one of its inputs, the data signal or the analogous signal may be provided by an external device;

[0030] - a completion of a post-production quality check. The completion is detected by finalization of the test procedure within the electrophoretic display device, for example by the control unit, which reaches a certain pre-defined processing stage without any failure event. The completion may also be communicated to the control unit by an external device by means of a data signal or an analogous signal.

[0031] - an entering into a post-production and / or post quality check delivery status, which is characterized by the fact that the electronic display device, once produced and / or quality tested, has not yet been entered into the infrastructure of a target installation for the first time. This may be detected by the control unit by reaching a pre-defined processing status in which the electronic display device is not connected to a foreign communication infrastructure. A foreign communication infrastructure is a communication infrastructure that is different from the communication infrastructure of the manufacturer.

[0032] - a radio communication with another device. The radio communication may for example by a proximity radio communication like for example an NFC based communication with an external NFC-device in which the decommission is instructed by the external NFC-device or a long-range radio communication for example with an access point or the like in which the decommission is instructed by means of a first command that is provided for example by a server or a cloud-based solution. The reception of the first command instructs the control unit to switch to the display of the white or single-color image. Such a radio communication may be applied in the manufacturing facility, for example after finishing the production or passing the quality check or entering the post-production delivery state. Such a radio communication may also be applied in the facility of a customer that applies the electronic display device in accordance with its business. Dependent on the actual realization of the electronic display device it may only comprise a long-range radio communication interface electronics or a proximity radio communication electronics or both types of communication electronics, which is / are connected to the control unit to be utilized for the mentioned purpose. The long-range communication interface electronics may be configured perform radio communication according to Bluetooth ®, ZigBee ® or any other standardized protocol or even according to a proprietary protocol like for example the protocol that is disclosed in the international patent application WO 2015 / 124197 Al. Further to this, it is clarified that the abbreviation NFC stands for "Near Field Communication" which is promoted by the NFC-Form (see https: / / nfc-forum.org) and standardized according to ISO / IEC 14443 Type A / Type B, ISO / IEC 15693, ISO / IEC 18092, etc.

[0033] - a detection of an interaction with a physically interactable element of the electrophoretic display like a button which can be pressed by a person handling the electronic display device or a pin-like structure at its rear side that is moved when the electronic display device is released from a holding structure, for example a shelf rail or a test stand or a wall and the like, where it was installed. Alternative, a light sensitive electrical element (photo transistor, photo diode or the like) may exist at the rear side of the electrical display device which delivers a signal when the electronic display device is released from the holding structure. This effect may can also be realized by a radar sensor that is used to check the proximity situation of the electrical display device. The respective physical interactable element is signal wise coupled to the control unit. This allows the control unit to poll the status of the respective element via one of its input pins (digital or analog signal input pin). Alternative, the signal from the respective physical interactable element may be fed to an interrupt pin of the control unit so that its occurrence initiates the execution of a particular software route at the control unit.

[0034] - an expiration of a pre-set duration in time. This can be implemented by means of digitally implemented timer that is controlled by the control unit. The pre-set duration time may be set to a few minutes, hours or even days. This feature may be used to secure that the period of non-usage is entered if for whatever reasons the displayed content did not change during the predefined duration (for example unjustifiable or unreasonably long duration). The fact that no update during the pre-set duration took place may be interpreted a general faulty operation or a lost connection to an external controlling device, for example an access point. The internal timer of the electronic display device secures that even in such a situation the risk of the creation of a sticking image is reduced.

[0035] The electrophoretic display device according to any of the preceding claims, wherein the control unit is configured to detect the occurrence of the activation event, in particular by the aid of an interaction detection element of the electronic display. In terms of the method, the method comprises the step of detecting the occurrence of the activation event by the control unit, in particular by the aid of an interaction detection element of the electronic display device.

[0036] The detection of the occurrence of the activation event may be softwarebased, for example based of the fact that the electronic display device joins a radio communication network at the customers facility. Hence the radio communication network is different from the manufacturer's radio communication network. The joining of the radio communication network becomes available to the control unit as radio communication parameter (typically the frequency band and one or more radio channels) for its internal radio communication device are set to be able to perform the radio communication within the radio communication network of the customer. Alternative, the detection of the occurrence of the activation event may take place after the joining of the radio communication network of the customer, through which the electronic device receives a second command to switch form the displaying of the white or single-color image to the displaying of the content visualizing image. In case of an NFC-enabled electronic display device the trigger to depart from the period of non-usage may be given by the receipt of an NFC-conform radio signal only or by the receipt of the command via the NFC-conform radio signal. A further software- based detection may be the event of logically binding the electronic display device to a product, service or room and the like, which can be detected by the control unit when it has received the first image data for the display of the content visualizing image. In all these scenarios the interaction detection element is realized by the respective radio communication electronics, so to say either by the long- range radio commination interface electronics or by the proximity radio communication interface electronics. The detection of the occurrence of the activation event may also be hardware-based, for example when powering up the electronics (battery supply activation / power supply connection) after being driven into the period of non-usage. The control unit may identify this event by checking the logic status of a flag in its register or the logic content of a memory cell of its memory device. Further to this also a manual interaction (pressing of a button of the electronic display device) may be detected by the control unit. In this scenario the interaction detection element is resized by the button.

[0037] Typically, one of the mentioned software- based or hardware-based trigger applies as the activation event. However, the activation event may also be an expiration of pre-set duration in time. Again, this feature can be implemented by means of digitally implemented timer that is controlled by the control unit. The pre-set duration in time may be set to a few minutes, hours or even days. This feature may be used to secure that the period of non-usage is terminated if for whatever reasons the displayed content did not change during the pre-defined duration (for example unjustifiable or unreasonably long duration). The fact that no update during the pre-set duration took place may be interpreted a general faulty operation or a lost connection to an external controlling device, for example an access point.

[0038] The content visualizing image may be any "human readable information", for example a reset indication, or a specific use-case determined information that was used before entering into the period of non-usage, for example a product related information or a room related information, etc. However, it has proven to be of particular advantage that the content visualizing image depicts a machine-readable code, in particular a barcode or a quick response code, which uniquely identifies the electronic display device. This allows the rapid inclusion of the respective electronic display device into the desired infrastructure after its electrophoretic display rested in the status of displaying the white or single-color image. Further to this, the display of such a basically machine-readable code leaves no doubt regarding the question of the status of the respective electronic display device. When showing the machine-readable code, it is unambiguously clear to the user that sees the code that the electronic display device requires a particular attention. The same applies for a system that automatically acquires and processes the displayed code. Based on the displayed code the electronic display device can be entered or re-entered, respectively, into the respective infrastructure and fed with first image data to show the represented content visualizing image or instructed to show the content visualizing image that is represented by the already stored first image data.

[0039] Regarding the timing and location of execution of the method it has proven to be of particular advantage that the entering into the period of nonusage occurs after a manufacturing and / or a testing at a first location, in particular a manufacturer's facility, and / or upfront to a sending to a second location, in particular a customer's facility. In other words, the control unit drives the electrophoretic display to display the white or single-color image after a manufacturing and / or a testing at a first location, in particular a manufacturer's facility, and / or upfront to a sending to a second location, in particular a customer's facility

[0040] Further to this it is of particular advantage that the period of nonusage is terminated earliest at the arrival at the second location. In other words, the activation event occurs earliest at the arrival at the second location, which triggers the control unit to drive the electrophoretic display to display the content visualizing image following the period of non-usage.

[0041] Such a timing in connection with the identified location(s) provides the advantage that the sticking of images which are displayed during the production process is sustainably avoided, because the protective measure of displaying the white or singe-color image is applied during the typically long lasting storage and delivering processes (by lorry from the factory to a harbor, by ship to a destination harbor, by lorry to a final destination, etc.) before the electronic display is put in operation at a customer.

[0042] The steps regarding the timing and location of execution might be executed by hardware and / or software. Preferably those steps are executed as part of a preferred embodiment of the computer-implemented method.

[0043] In general, the computer-implemented method is preferably provided as a computer program (product) and / or executed on the basis of such a computer program (product).

[0044] Therefor an aspect of the invention relates to a computer program (product) comprising instructions which, when the program is executed by a computer, cause the computer to carry out the computer-implemented method according to the invention. Another aspect of the invention relates to a computer-readable (storage) medium and / or a data carrier signal comprising instructions which, when executed by a computer, cause the computer to carry out the computer-implemented method according to the invention. Lastly, it should generally also be mentioned that the discussed electronic devices obviously have electronics. The electronics can be constructed discretely or by means of integrated electronics or also a combination of both. Microcomputers, micro controllers, Application Specific Integrated Circuits (ASICs), optionally in combination with analog or digital electronic peripheral components can also be used. Many of the mentioned functionalities of the devices - optionally in interaction with hardware components - are realized with the help of a software, which is executed on a processor of the electronics. Devices realized for the radio communication usually have an antenna configuration as part of a transceiver module for sending and receiving radio signals. These aspects do apply in particular to the electrophoretic display device and the control unit. The electronic devices can additionally have an internal electric power supply, which can be realized, for example, with a replaceable or chargeable battery. The devices can also be supplied in a wired manner, either by means of an external power supply or also by means of "power over LAN".

[0045] These and further aspects of the invention follow from the below- discussed figures.

[0046] Brief Description of the Figures

[0047] The invention will be described once again in more detail below with reference to the enclosed figures based on exemplary embodiments, to which the invention is not limited, however. Identical components are thereby provided with identical reference numerals in the various figures. Schematically:

[0048] Fig. 1 shows a system with an electronic display device that comprises an electrophoretic display for displaying black and white images;

[0049] Fig. 2 shows a sequence of different images displayed by the electronic display device.

[0050] Description of the Exemplary Embodiments Figure 1 shows a system 1, which comprises an electronic display device 2, an access point 3, and a server 4. In the present scenario the electronic display device 2 embodies in the technical jargon an Electronic Shelf Label that is typically abbreviated as ESL and that is mainly used in retail to display product related information.

[0051] The server 4 is used to supply first image data ID1 to the ESL 2, which are intended to be displayed by the ESL 2. The first image data ID1 are used to show a fruit 5 (apple or pear) and accompanying product information and / or price information 6.

[0052] The access point 3 is connected to the server 4 via a (cable basted) local area network 7. The access point 3 is configured for radio communication with the ESL 2. In the present case Bluetooth ® is used.

[0053] In the following a first embodiment of the electronic display device is explained.

[0054] The electronic display device 2 comprises a battery 8 to provide a reference potential GND and supply a supply voltage VCC for the entire electronics of the electrical display device 2.

[0055] The electronic display device 2 further comprises a commercially available black and white electrophoretic display 9 that is used to display either a content visualizing image 10 or a white image 11 (see Figure 2).

[0056] The content visualizing image 10 is assembled with black and white image elements (pixels), wherein information carrying elements like the structure of the fruit and text and / or number(s) and / or symbol(s) is / are visualized in black while the surrounding, which can be understood as background, is visualized in white. The entire assembly of black and white content of the content visualizing image is represented by the first image data ID1. Once received from the server 4, the first image data ID1 are stored by a memory device 12 (for example an EEPROM, Electronically Erasable Programmable Read-Only Memory).

[0057] The white image 11 is represented by second image data ID2, which are pre-programmed or pre-stored, respectively, in the memory device 12. The white image 11 shows only white pixels. The pre-programming is performed during manufacturing of the electronic display device. The white image 11 is used during a period of non-usage when there is no need to visualize any human or machine processable content. The electronic display device 2 further comprises a radio communication stage 13, which is arranged for a Bluetooth® radio communication with the access point 3 and utilizes an antenna configuration

[0058] 14.

[0059] The electronic display device 2 further comprises a processing stage

[0060] 15, which is configured for execution of an operation system (a program) that is stored in a read only memory of the processing stage (not shown in detail). The processing stage 15 controls the communication with the access point 3 and decides which of the stored image data ID 1 or ID2 are made available for the electrophoretic display device 9. This decision is determined by a command CD that either indicates that the first image data ID1 or the second image data ID2 is accessed and supplied via an internal bus 16 to the electrophoretic display 9. The command DC is supplied by the server and received and executed by the processing stage 15.

[0061] In the present embodiment the processing stage 15, the radio communication stage 13 and the memory stage 12 assemble a control unit 17 of the electronic display device 2. The control unit 17 is realized by a microcontroller.

[0062] Although the Figure 1 depicts only one electronic display device 2 and only one access point 3 for the sake of simplicity in depicting the basic infrastructure it is to mention that typically a plurality of electronic display devices 2 is served by one access point 3, while multiple access points 3 provide a radio communication sevice for a plurality of groups of the electronic display devices 2, each group is connected to one of access points 3. In the following it is further assumed that such an infrastructure exists in at least a similar configuration at a manufacturer's facility where the electronic display device 2 is manufactured and quality tested and at a customer's facility where the electronic display device 2 is operated. In the present scenario the customer is a retailer that uses the electronic display device 2 in its shops to display a product and / or price information as the content visualizing image 10.

[0063] In the following reference is made to Figure 2 to explain the operation of the electronic display device 2. Figure 2 shows a sequence of different images displayed by the electronic display device 2. In the Figure 2 only the electrophoretic display 9 of the electronic display device 2 is shown. Along a timeline t the electrophoretic display 9 displays an alternating sequence of the content visualizing image 10 and the white image 11. The timeline t shows timestamps tO to t6. The timestamp tO indicates the beginning of the timeline t.

[0064] During a first period DI the electronic display device 2 is manufactured and tested at the manufacturer's facility. Manufacturing takes place between the timestamps to and tl. Testing takes place between the timestamps tl and t2. It is assumed that during testing the electronic display device 2 is instructed by the radio communication with the access point 3 to display one or more of the content visualization images 10, so that its proper operation can be verified.

[0065] During a second period D2, which is a first example of the period of non-usage, the electronic display device 2 is delivered to the customer's facility. During the second period D2 there is no need for displaying any content visualizing image 10. In fact, it has been shown that after a long transport during which content is displayed, ghosting of the electrophoretic display often occurs. Therefore, at the end of the first period DI, the electronic display device 2 is instructed by the radio communication, in which it receives the command DC, to display the white image 11. The white image 11 is displayed during the entire second period D2 to protect or to reduce the risk of image sticking.

[0066] During a third period D3 the electronic display device 2 is in the possession of the retailer. The retailer operates a shop (or store). When in use in the retailer's shop, which means that the electronic display device 2 is intended to display the product and / or price information at for example a shelf, the electronic display device 2 is instructed by the radio communication to display the content visualizing image 10. Each time the electronic display is assigned to a particular product (for example grapes or pears), which is often termed as binding, it receives via the radio communication an individual content visualizing image 10 that shows the particularities of the respective product. In the present scenario this allows the electronic display device 2 to show information related to grapes between the timestamps t3 and t4 and to shows information rated to pears between the timestamps t5 and t6. During the timestamps t4 and t5, which is a second example of the period of nonusage, and during the timestamps t6 and t7, which is a further example of the period of non-usage, again there is no need to display any content visualizing image 10 because the electronic display device 2 may be taken out of the shelf and placed in a storage at the customer's facility for later use. Therefore, at the timestamp t4 and t6 the electronic display device 2 is instructed by the radio communication, in which it receives the command DC, to display the white image 11. Again, the white image 11 is displayed during the entire time periods between the timestamps t4 and t5 or t6 and t7, respectively, to reduce the risk of image sticking.

[0067] At the end of the respective period of non-usage the electronic display device 2 is triggered in the radio communication with the access point, in which it receives the command CD, to display the content visualizing image 10 that is available by means of the first image data ID1 that are stored in the memory device 12. As the electronic display device 2 is linked by a radio connection to the access point 3 also during the period of non-usage, the first image data ID1 may be updated upfront to the reception of the command DC. However, the update of the first image data ID1 may also take place together with the reception of the command DC or thereafter.

[0068] According to a further embodiment the electronic display device 2 comprises an internal NFC-device that is configured to provide an NFC- communication with an external NFC-device. The internal NFC-device is signal wise connected to the processing stage 15. It may also be implemented that the internal NFC-device electrically powers the processing stage 15 or the entire control unit 17 with the power supply voltage that is generate during the inductive coupling with the external NFC-device. In this embodiment the processing stage 15 is configured to enter the period of non-usage triggered by a communication with the external NFC-device and to terminate the period of non-usage by a further communication with the external NFC-device. Consequently, the electronic display device 2 doesn't need to stay in radio contact with the access point 3 within the retailer's facility to switch between the displaying of the white image 11 and the content visualizing image 10. During the period of non-usage, the control unit 17 may even be halted so that it hardly drains any power, which has a significant impact on the lifetime of the battery 8. The halted control unit 17 is reactivated by the electrical power suppled during the inductive coupling with the external NFC-device. According to a further embodiment the electronic display device 2 comprises - instead of the battery 8 and the radio communication stage 13 together its antenna configuration 14 - contact elements that are used to electrically contact external power supply lines and external data signal lines. Such a type of electrical display device 2 is for example known from the international patent application WO 2022 / 188956 Al. Entering the period of non-usage and exiting the period of non-usage may be driven by data signals via the data signal lines. If also an internal NFC-device is included in the electronic display device the entry into and the exit from the period of non- usage may be controlled by the NFC-communication with the external NFC- device. Also, in this embodiment the displaying of the white image or the single-color image achieves the same effect as it was explained in the context of the other embodiments.

[0069] Lastly, it is pointed out once again that the figures described in detail above are only exemplary embodiments, which the person of skill in the art can modify in a large variety of ways, without leaving the scope of the invention. For the sake of completeness, it is also pointed out that the use of the indefinite article "a" does not rule out that the respective features can also be present in multiple.

Claims

Claims1. An electronic display device (2), in particular an electronic label, more particular an electronic shelf label, which comprises:- an electrophoretic display (9) to display a content visualizing image (10) that is represented by first image data (ID1), and- a control unite (17) that has access to the first image data (ID1) and that is configured to drive the electrophoretic display (9) according to the first image data (ID1), characterized in that the control unit (17) is configured:- to drive the electrophoretic display (9) to display a white or a single-color, in particular content-free, image (11) when entering into a period of nonusage, and,- upon an occurrence of an activation event that terminates the period of non-usage, to drive the electrophoretic display (9) to display the content visualizing image (10).2 The electronic display device (2) according to claim 1, wherein the control unit (17) is configured to drive the electrophoretic display (9) to display the white or single-color image (11) throughout its entire visualization area.

3. The electronic display device (2) according to claim 1, wherein the control unit (17) is configured to generate second image data (ID2) when entering the period of non-usage, wherein the second image data (ID2) represent the white or the single-color image (11).

4. The electronic display device (2) according to claim 1, wherein- wherein the electronic display device (2) comprises a memory stage (12) to store second image data (ID2), which represent the white or the singe color image (11), and- wherein the control unit (17) is configured to make available the second image data (ID2) for the electrophoretic display (9) when entering the period of non-usage.

5. The electronic display device (2) according to claim 1, wherein the electronic display device (2) comprises a memory stage (13) to stores the first image data (ID1), and the control unit (17) is configured to make available the first image data (ID1) for the electrophoretic display (9) as a consequence of the occurrence of the activation event.

6. The electronic display device (2) according to any of the preceding claims, wherein the control unit (17) is configured to identify a decommission event as an indicator of the entering into the period of non-usage.

7. The electronic display device (2) according to any of the preceding claims, wherein the control unit (17) is configured to detect the occurrence of the activation event, in particular by the aid of an interaction detection element (13) of the electronic display device (2).

8. The electronic display device (2) according to any of the preceding claims, wherein the content visualization image (11) depicts a machine- readable code, in particular a barcode or a quick response code, which uniquely identifies the electronic display device (9).

9. A method for operating an electronic display device (2), in particular an electronic label, more particular an electronic shelf label, wherein the method is performed by the electronic display device (2) that comprises an electrophoretic display (9) and a control unit (17) that has access to first image data (ID1), which first image data (ID1) represent a content visualizing image (10), the method comprises the following steps, namely:- driving the electrophoretic display (9) by the control unit (17) according to the first image data (ID1) to display the content visualizing image (10), characterized in that the method comprise the steps of:- driving the electrophoretic display (9) by the control unit (17) to display a white or a single color, in particular content-free, image (11) when entering into a period of non-usage, and,- upon an occurrence of an activation event that terminates the period of non-usage, driving the electrophoretic display (9) by the control unit (17) to display the content visualizing image (19).

10. The method according to claim 9, wherein the method comprises the step of driving the electrophoretic display (9) by the control unit (17) to display the white or single-color image (11) throughout its entire visualization area.

11. The method according to claim 9, wherein the method comprises the step of generating second image data (ID2) by the control unit (17) when entering the period of non-usage, wherein the second image data (ID2) represent the white or the single-color image (11).

12. The method according to claim 9, wherein the method comprises the steps of:- storing second image data (ID2) by a first memory stage of the electronic display device (2) and- making available the second image data (ID2) by the control unit (17) for the electrophoretic display (9) when entering the period of non-usage.

13. The method according to any of the preceding claims 9 to 12, wherein the method comprises the steps of:- storing the first image data (ID1) by a second memory stage and- making available the first image data (ID1) by the control unit (17) for the electrophoretic display (9) as a consequence of the occurrence of the activation event.

14. The method according to any of the preceding claims 9 to 13, wherein the method comprises the step of identifying by the control unit (17) a decommission event as an indicator of the entering into the period of non- usage.

15. The method according to any of the preceding claims 9 to 14, wherein the method comprises the step of detecting the occurrence of the activation event by the control unit (17), in particular by the aid of an interaction detection element (13) of the electronic display device (2).

16. The method according to any of the preceding claims 9 to 15, wherein the entering into the period of non-usage occurs after a manufacturing and / or a testing at a first location, in particular a manufacturer's facility, and / or upfront to a sending to a second location, in particular a customer's facility.

17. The method according to claim 16, wherein the period of non-usage is terminated earliest at the arrival at the second location.

18. A method for producing an electronic display device (2), in particular an electronic label, more particular an electronic shelf label, wherein the method comprises the steps of:- manufacturing and / or testing the electronic display device (2) according to any of the preceding claims 1 to 8, and,- thereafter, driving the electrophoretic display (9) by the control unit (17) to display a white or a single color, in particular content-free, image (11) when entering into the period of non-usage.19 Computer implemented method for operating an electronic display device (2), in particular an electronic label, more particular an electronic shelf label, comprising an electrophoretic display (9), wherein the method comprises the following steps, namely:- generating driving data for driving the electrophoretic display (9) according to first image data (ID1), wherein the first image data (ID1) represent a content visualizing image (10), characterized in that the method comprise the steps of:- generating driving data for driving the electrophoretic display (9) to display a white or a single color, in particular content-free, image (11) when entering into a period of non-usage, and,- upon an occurrence of an activation event that terminates the period of non-usage, generating driving data for driving the electrophoretic display (9) to display the content visualizing image (19).

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