The present invention relates to a method for indicating low power level of an electronic shelf label comprising a battery and a corresponding electronic shelf label device.
In different types of stores, for example supermarkets etc., electronic shelf labels, also referred to as ESLs, are used for displaying information about the different products offered in the store. The information displayed is for example the name and type of product as well as the price for each of the products. In an ESL system of a store, the electronic shelf labels are typically communicating with a central control unit which makes it possible to update and change the information displayed on the labels which saves a considerable amount of time for the persons working in the store, especially if the number of different products sold in the store is high. As an example, a supermarket offers between 50000 and 100000 different products.
It is known to use bistable displays in ESLs, like electronic paper (or e-paper) devices, which has the advantage that the bistable display is only turned on when it is desired or needed to change and update the information displayed on the ESL. Furthermore, many display technologies hold static text and images indefinitely without electricity. There are many known approaches to bistable displays including e-paper, or electrophoretic arrangements, modifications of liquid crystal displays, electrochromic displays and multi-stable smectic LCDs etc.
Wireless communication with the central control unit (or locally by means of e.g. an IR device or other contact-less means) via transmitting and receiving means arranged in each ESL device is typically used to update pricing information or other information (label information) displayed on the ESL. In the example of a grocery store or retailer, each ESL device is provided with one or more batteries to provide power to the ESL when the information displayed on the ESL is updated. Since each battery stores a limited amount of energy, and it is known that standby leakage current while the ESL is also in standby mode depletes battery life significantly, the labels are either disposed and replaced by a new label when the battery is empty, or alternatively the batteries must be replaced to ensure that the ESL device can be updated. Replacing the battery when needed or exchanging ESL devices with empty batteries is a labor intensive operation for a store of any size with many ESLs, and if not attended to in time, the risk of displaying incorrect product and price information due to non-updated ESL labels increases. There is consequently a need for an improved electronic shelf label arrangement to better attend to ESLs in which the battery has reached a critically low power level.
The present invention as defined in the appended claims, provides an electronic shelf label device and method therefore that fulfils the needs defined above.
According to a first aspect of the inventive concept, there is provided a method for indicating a battery power level of an electronic shelf label, ESL, device comprising a multi-stable display for displaying information, in which the remaining power level of a battery providing electric power to the ESL is monitored for determining if the power level of the battery drops below a first preselected threshold value corresponding to a critical power level, and in response thereof updating the multi-stable display according to a first predetermined information associated with the critical power level. The first predetermined information is preferably selected to in a distinct manner reflect the fact that the ESL is no longer responsive to updates with new label information, thereby controlling the displayed information such that no misleading price information is displayed to customers. This further facilitates for the staff to visually identify which ESL devices are out of power and needs to be attended to, either by exchanging the battery or by replacing the ESL device.
According to embodiments of the invention, the first predetermined information is selected from one of a stable state of the multi-stable display, which is advantageous, a black image, a color image, a preselected word, and a preselected symbol, where the color, word or symbol is preferably selected to clearly distinguish ESL devices which are reaching the critical power level of the battery, or which are out of power, from functioning ESL devices whose batteries have a remaining capacity sufficient to enable reliable updates of their label information.
According to an embodiment, an alarm device on the ESL or in a central control system is activated as the critical power level of the battery is reached. Such an alarm may advantageously be provided by connecting a light emitting diode to the battery, thereby utilizing the last of the remaining power to help identify the ESL to the staff. Another applicable alarm device may be an audio alarm.
According to an embodiment, the method further comprises sending an out of power message to an external central control system arranged for providing label information to the ESL device, which is advantageous to identify out of power ESLs, and to prevent the central control system from pushing updates to the non-responsive ESL.
According to an embodiment, the method further comprising before the step of determining if the power level of the battery drops below the first preselected threshold value determining if the power level of the battery drops below a second preselected threshold value selected between 30-50% of full power level, and in response thereof: sending a battery status message to the external central control system arranged for providing label information to the ESL device, thereby indicating that the remaining battery capacity (or life time) has decreased as compared to the fully charged battery status, and that maintenance is required within a near future.
According to an embodiment, the method further comprises before the step of determining if the power level of the battery drops below the first preselected threshold value determining if the power level of the battery drops below a third preselected threshold value selected between 10-29% of full power level, and in response thereof: updating at least a sub portion of the multi-stable display according to a second predetermined information associated with a low power level while still displaying current label information on the multi-stable display. The second predetermined information is preferably selected to provide a visual indication that the remaining battery is decreasing and approaching a critical level, e.g. by providing a specific color, a symbol or word indicating low power.
According to a second aspect of the inventive concept, there is provided an electronic shelf label, ESL, device comprising a battery for supplying electric power to the ESL, a multi-stable display element for displaying information, an ESL control means arranged for updating the information of the multi-stable display, and battery control means arranged for monitoring a remaining power level of the battery, and notifying the ESL control means when the power level of the battery drops below a first preselected threshold value, corresponding to a critical power level of the battery. The ESL control means is further arranged for in response to being notified updating the multi-stable display element according to a first predetermined information associated with the critical power level. The first predetermined information is according to embodiments of the ESL device selected from one of a stable state of the multi-stable display, a black image, a color image, a preselected word, and a preselected symbol. The ESL may further comprise an alarm device which is activated when the power level of the battery drops below the first preselected threshold value, and may further comprise a transmitting and receiving means connected to the ESL control means for enabling communication with an external central control system, in which case the ESL control means may further be arranged to send an out of power message to the central control system.
According to an embodiment of the ESL, the battery control means is further arranged for notifying the ESL control means when the power level of the battery drops below a second preselected threshold value selected between 30-50% of full power level. The ESL control means is arranged for in response thereof sending a battery status message to the central control system.
According to an embodiment of the ESL, the battery control means is further arranged for notifying the ESL control means when the power level of the battery drops below a third preselected threshold value selected between 10-29% of full power level. The ESL control means is arranged for in response thereof updating at least a sub portion of the multi-stable display according to a second predetermined information associated with a low power level while still displaying current label information on the multi-stable display.
According to an embodiment of the ESL and/or method the critical power level of the battery is selected between 1-9% of full power level. Further, according to an embodiment the multi-stable display element comprises e-paper. As used herein, electronic paper, e-paper, or electronic ink display are interchangeable terms used to reference display technology that mimics the appearance of ordinary ink on paper by reflecting light like ordinary paper. It is able to hold text and images indefinitely without drawing electricity, unlike a conventional flat panel display that illuminate's pixels or a reflective LCD display that requires regular screen content refresh.
Note that although the detailed description exemplifies bistable displays, displays with e.g. displays with multi-stable states, e.g. multi-stable electrophoretic displays with gray scale (as mentioned in e.g. Acrylates-Advances in Research and Application: 2013 Edition and U.S. Pat. No. 7,170,570), etc. are applicable within the present inventive concept.
The advantages described for the respective embodiments of the method described above apply also to the corresponding embodiments of the ESL according to the current inventive concept.
Further objectives of, features of, and advantages with, the present invention will become apparent when studying the following detailed disclosure, the drawings and the appended claims. Those skilled in the art realize that different features of the present invention can be combined to create embodiments other than those described in the following.
The above will be better understood through the following illustrative and non-limiting detailed description of preferred embodiments of the present invention, with reference to the appended drawings, where the same reference numerals will be used for similar elements, and wherein:
All the figures are schematic, not necessarily to scale, and generally only show parts which are necessary in order to elucidate the invention, wherein other parts may be omitted or merely suggested.
An illustrative curve of a battery EMF over time is plotted in
Referring now to
ELS 100 includes an alarm 107 (optional) which may be provided by e.g. a small sonic device or a light emitting diode which according to an embodiment is connected via a switch to the battery 104 when activated, to utilize the last power available from the battery as the critical level of the battery is reached.
Referring now to
Referring now to
The different embodiments described above could all be combined and modified in different ways without departing from the scope of the invention that is defined by the appended claims.
Number | Date | Country | Kind |
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18158848.4 | Feb 2018 | EP | regional |