Patent Publication Number: US-11397447-B2

Title: Electronic label and method for driving the same

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is a continuation-in-part of U.S. application Ser. No. 16/828,160, filed Mar. 24, 2020, entitled “ELECTRONIC LABEL AND METHOD FOR DRIVING THE SAME”, by Yunyan Xie, Bo Liu, and Lichun Chen, which claims priority to the Chinese Patent Application No. 201910881285.7, filed on Sep. 18, 2019, both of which are incorporated herein by reference in their entireties. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to the field of display technology, and more particularly, to an electronic label and a method for driving the same. 
     BACKGROUND 
     With the progress of technology and the development of Internet of Things technology, electronic labels have been widely used. The electronic labels have advantages such as low power consumption and environmental protection, and may be connected to an offline scene database through a wireless network to display relevant information in real time and accurately. Therefore, the trend of replacing paper labels with the electronic labels has become. 
     However, the electronic labels have problems such as a high manufacturing cost and inflexible display. 
     SUMMARY 
     According to an aspect of the present disclosure, there is provided an electronic label, comprising: 
     a plurality of display screens; 
     a repeater configured to receive content data to be displayed on the plurality of display screens and distribute the content data to a communicator according to a signal strength between the repeater and the communicator; 
     the communicator configured to receive the content data from the repeater; and 
     a controller comprising a serial data interface and configured to transmit, through the serial data interface, the content data to be displayed on the plurality of display screens and a control signal generated by the controller for controlling the plurality of display screens to the plurality of display screens respectively, so as to control the plurality of display screens to display the respective content data received according to the control signal. 
     In some embodiments, the serial data interface comprises: 
     at least one selection interface configured to select at least one of the plurality of display screens; 
     a clock interface configured to transmit a synchronization clock signal to the plurality of display screens; and 
     a data interface configured to serially transmit the content data to be displayed on the plurality of display screens and the control signal to the plurality of display screens under synchronous control of the synchronization clock signal. 
     In some embodiments, the controller is further configured to: 
     select the plurality of display screens through the at least one selection interface at the same time in response to the content data to be displayed on the plurality of display screens being the same; and 
     sequentially select at least one of the plurality of display screens through the at least one selection interface in response to the content data to be displayed on the plurality of display screens being different. 
     In some embodiments, a number of the at least one selection interface is less than or equal to a number of the plurality of display screens. 
     In some embodiments, when a number of the at least one selection interface is less than a number of the plurality of display screens, selection signals transmitted through the at least one selection interface are encoded and decoded to generate a selection signal corresponding to each of the plurality of display screens. 
     In some embodiments, each of the plurality of display screens comprises a buffer configured to store content data received from the controller to be displayed on the display screen. 
     In some embodiments, the display screens are electronic ink screens, and 
     the electronic label further comprises a booster circuit connected to the electronic ink screens and configured to power on and power off the electronic ink screens. 
     In some embodiments, the booster circuit is further connected to the controller, and is controlled by the controller to power on and power off the electronic ink screens. 
     In some embodiments, the content data comprises a type flag and an end flag, wherein the type flag is used to indicate whether the transmitted data is content data or a control signal, and the end flag is used to indicate the end of data transmission. 
     In some embodiments, the communicator is further configured to receive control instructions form an application installed on a mobile phone, and wherein the at least one of the plurality of display screens is to be controlled according to the control instructions. 
     In some embodiments, the electronic label further comprises: 
     a charger interface configured to charger the electronic label. 
     According to another aspect of the present disclosure, there is provided a method for driving the electronic label, comprising: 
     receiving, by the repeater, content data to be displayed on the plurality of display screens; 
     distributing, by the repeater, the content data to the communicator according to a signal strength between the repeater and the communicator; 
     receiving, by the communicator, the content data from the repeater; 
     transmitting, by the controller, through the serial data interface, the content data to be displayed on the plurality of display screens and a control signal generated by the controller for controlling the plurality of display screens to the plurality of display screens respectively; and 
     displaying, by the plurality of display screens, the respective content data received according to the control signal. 
     In some embodiments, the serial data interface comprises a clock interface, a data interface and at least one selection interface, and 
     wherein transmitting, by the controller, through the serial data interface, the content data to be displayed on the plurality of display screens and a control signal generated by the controller for controlling the plurality of display screens to the plurality of display screens respectively comprises: 
     selecting at least one of the plurality of display screens through the at least one selection interface; 
     transmitting a synchronization clock signal to the plurality of display screens through the clock interface; and 
     serially transmitting the content data to be displayed on the plurality of display screens and the control signal to the plurality of display screens through the data interface under synchronous control of the synchronization clock signal. 
     In some embodiments, selecting at least one of the plurality of display screens through the at least one selection interface comprises: 
     selecting, by the controller, the plurality of display screens at the same time through the at least one selection interface in response to the content data to be displayed on the plurality of display screens being the same; and 
     sequentially selecting, by the controller, at least one of the plurality of display screens through the at least one selection interface in response to the content data to be displayed on the plurality of display screens being different. 
     In some embodiments, the data content transmitted by the controller through the data interface to be displayed on the selected at least one display screen is serially received by the at least one display screen under the synchronous control of the synchronization clock signal in response to the controller sequentially selecting at least one of the plurality of display screens through the at least one selection interface, until the content data to be displayed on the plurality of display screens is sequentially received by the respective display screens. 
     In some embodiments, a number of the at least one selection interface is less than or equal to a number of the plurality of display screens. 
     In some embodiments, when the number of the at least one selection interface is less than the number of the plurality of display screens, the method further comprises: encoding and decoding selection signals transmitted through the at least one selection interface to generate a selection signal corresponding to each of the plurality of display screens. 
     In some embodiments, each of the plurality of display screens comprises a buffer, and 
     before the plurality of display screens display the respective content data received according to the control signal, the method further comprises: 
     storing, by the plurality of display screens, the content data received from the controller to be displayed thereon in the respective buffers. 
     In some embodiments, the content data comprises a type flag and an end flag, wherein the type flag is used to indicate whether the transmitted data is content data or a control signal, and the end flag is used to indicate the end of data transmission. 
     In some embodiments, the method for driving the electronic label further comprises: 
     receiving, by the communicator, control instructions form an application installed on a mobile phone; and wherein the at least one of the plurality of display screens is to be controlled according to the control instructions. 
    
    
     
       BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS 
       The above and other purposes, features, and advantages of the embodiments of the present disclosure will become more obvious by describing the embodiments of the present disclosure with reference to the accompanying drawings. It should be illustrated that throughout the accompanying drawings, the same elements are represented by the same or similar reference signs. In the accompanying drawings: 
         FIG. 1  schematically illustrates an application scenario of an electronic label; 
         FIGS. 2  A to  2 C schematically illustrate structural block diagrams of an electronic label according to an embodiment of the present disclosure; 
         FIG. 3  schematically illustrates a structure of a serial data interface of an electronic label according to an embodiment of the present disclosure; 
         FIG. 4  schematically illustrates a flowchart of a method for driving an electronic label according to an embodiment of the present disclosure; 
         FIG. 5A  schematically illustrates a flowchart of a method for driving an electronic label according to an example of the present disclosure; 
         FIG. 5B  schematically illustrates a signal timing diagram of the exemplary method shown in  FIG. 5A ; 
         FIG. 6A  schematically illustrates a flowchart of a method for driving an electronic label according to another example of the present disclosure; and 
         FIG. 6B  schematically illustrates a signal timing diagram of the exemplary method shown in  FIG. 6A . 
     
    
    
     DETAILED DESCRIPTION 
     In order to make the purposes, technical solutions and advantages of the embodiments of the present disclosure more clear, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present disclosure. Obviously, the embodiments described are a part of the embodiments of the present disclosure instead of all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present disclosure without contributing any creative work are within the protection scope of the present disclosure. In the following description, some specific embodiments are for illustrative purposes only and are not to be construed as limiting the present disclosure, but merely examples of the embodiments of the present disclosure. The conventional structure or construction will be omitted when it may cause confusion with the understanding of the present disclosure. It should be illustrated that shapes and dimensions of components in the figures do not reflect true sizes and proportions, but only illustrate contents of the embodiments of the present disclosure. 
     Unless otherwise defined, technical terms or scientific terms used in the embodiments of the present disclosure should be of ordinary meanings to those skilled in the art. “First”, “second” and similar words used in the embodiments of the present disclosure do not represent any order, quantity or importance, but are merely used to distinguish between different constituent parts. 
     Furthermore, in the description of the embodiments of the present disclosure, the term “connected to” or “connected with” may mean that two components are directly connected, or that two components are connected via one or more other components. In addition, the two components may be connected or coupled by wire or wirelessly. 
     Further, in the description of the embodiments of the present disclosure, the terms “first level” and “second level” are only used to distinguish amplitudes of the two levels. For example, the following description is made by taking the “first level” being a relatively high level and the “second level” being a relatively low level as an example. It may be understood by those skilled in the art that the present disclosure is not limited thereto. 
     The electronic labels are developed from original electronic price labels, and are mainly used in public places such as shopping malls, supermarkets etc. With the development of the Internet of Things technology and the application of the electronic labels and their derivatives, the diversified application of the electronic labels may become an inevitable trend in the development of information technology.  FIG. 1  illustrates an exemplary application scenario of an electronic label. As shown in  FIG. 1 , the electronic label  10  is used as an electronic table card in an office, a media, a conference, etc. 
     As more and more application scenarios are developed, problems of the electronic labels also gradually appear. On the one hand, with the increase in the demand for display information and the increase in display content, the demand for the electronic labels has increased significantly. Each of the electronic labels generally has a display screen and is driven by one driving circuit, and therefore if a large number of electronic labels are used, it may lead to a high cost. On the other hand, the public has more and more new requirements for display forms and appearance etc. of the electronic labels. This requires the electronic labels not only to update the display content in time, but also have more flexibility and display diversity. For example, in a scenario shown in  FIG. 1 , it is more desirable that the electronic table card may display content on opposite sides. Further, according to needs in actual situations, the electronic table card may display the same content on the opposite sides or display different content on the opposite sides. However, there is currently no solution for these applications. 
     According to the technical solutions of the embodiments of the present disclosure, there is provided an electronic label, in which content data is transmitted to a plurality of display screens by a controller, which significantly reduces a manufacturing cost of the electronic label. In addition, the content data to be displayed is transmitted to the plurality of display screens through a serial data interface of the controller, which may reduce a number of interfaces of the controller and simplify data transmission between the controller and the display screens. Further, the display screens may display separately according to the respective content data received, which increases flexibility of operations of the electronic label. 
     According to an embodiment of the present disclosure, there is provided an electronic label. The electronic label according to the embodiment of the present disclosure may comprise a plurality of display screens. The electronic label according to the embodiment of the present disclosure may further comprise a communicator configured to receive content data to be displayed on the plurality of display screens. The electronic label according to the embodiment of the present disclosure may further comprise a controller. The controller may comprise a serial data interface. The controller is configured to transmit the content data to be displayed on the plurality of display screens and control signal generated by the controller for controlling the plurality of display screens to the plurality of display screens through the serial data interface, respectively, to control the plurality of display screens to display the respective content data received according to the control signal. 
       FIG. 2A  schematically illustrates a block diagram of an electronic label according to an embodiment of the present disclosure. As shown in  FIG. 2A , the electronic label  20  according to the embodiment of the present disclosure may comprise a plurality of display screens  210   1  to  210   N  and a driving circuit  220 , wherein N is an integer greater than or equal to 2. 
     In some embodiments, the display screens may be electronic ink screens. The electronic ink screens are implemented by a display technology for simulating papers, and therefore are also referred to as electronic papers. Although the electronic ink screens are usually more expensive than commonly-used display screens, since the electronic ink screens have characteristics such as bi-stable display, the electronic ink may be powered on during data transmission and maintain the display when they are powered off. Therefore, the electronic ink screens are particularly suitable for a scenario in which static display and high requirements for energy consumption are required, and thus are increasingly used in the electronic labels. Of course, it may be understood by those skilled in the art that the embodiments of the present disclosure may also be applied to other general-purpose active display screens (for example, Liquid Crystal (LCD) display screens or Light Emitting Diode (LED) display screens, etc.) 
     The driving circuit  220  is used to drive the plurality of display screens  210   1  to  210   N . As shown in  FIG. 2A , the driving circuit  220  may further comprise a power supply circuit  2201 , a communicator  2202 , a controller  2203 , and a memory  2204 . 
     The power supply circuit  2201  is connected to the communicator  2202 , the controller  2203 , and the memory  2204 , respectively, and is used to supply power to the communicator  2202 , the controller  2203 , and the memory  2204 . 
     The communicator  2202  is used to receive content data to be displayed on the plurality of display screens  210   1  to  210   N  from an external source. The external source may be, for example, an external server, an external database, a cloud server, a mobile terminal, etc., and the embodiments of the present disclosure are not limited thereto. The communicator  2202  may be, for example, a wireless communication apparatus configured to perform communication based on a wireless transmission protocol. The wireless transmission protocol comprises, but not limited to, Bluetooth, WIFI, Zigbee, or mobile communication protocols based on technologies such as 3G, 4G etc. After receiving the content data to be displayed on the plurality of display screens  210   1  to  210   N , the communicator  2202  temporarily stores the content data in the memory  2204 . 
     The memory  2204  is used to temporarily store the received content data, and may be configured as a volatile storage medium or a non-volatile storage medium. In addition, the memory  2204  is further used to temporarily store instructions required by the controller  2203  and data generated by the controller  2203  during operations. 
     In some embodiments, the driving circuit  220  may further comprise a booster circuit  2205 . When the display screens are electronic ink screens, the booster circuit may be configured in the driving circuit  220  to provide a power supply voltage to the electronic ink screens. As described above, the electronic ink screens may be powered on during data transmission and may be powered off and display after the data transmission. Therefore, the booster circuit  2205  is configured in the driving circuit  220 , so that power may be supplied by the booster circuit  2205  to the electronic ink screens before the content data to be displayed on the electronic ink screens is transmitted thereto, and power-on of the electronic ink screens ends after display of the content data is refreshed. As shown in  FIG. 2A , the booster circuit  2205  is connected to the power supply circuit  2201 , which may be used to supply power to the booster circuit  2205 . The booster circuit  2205  is further connected to the plurality of display screens  210   1  to  210   N  (i.e., electronic ink screens) respectively, to power on and power off the electronic ink screens. The booster circuit  2205  is further connected to the controller  2203 , and the controller  2203  controls the above power-on and power-off processes, which is beneficial to reducing the energy consumption of the entire electronic label. 
     When the display screens are general-purpose active display screens (for example, LCD display screens or LED display screens etc.), it is necessary to continuously supply power to the display screens during the display process thereof. Therefore, this type of display screens usually each have a power supply (for example, a battery slot) integrated therein, and the display screens are supplied with power by themselves. Therefore, the booster circuit  2205  may not be provided in the driving circuit  220 . 
     The controller  2203  controls the overall operation of the driving circuit  220 , comprising controlling a communication process of the communicator  2202 , controlling a storage process of the memory  2204 , controlling power-on and power-off processes of the booster circuit  2205 , etc. In addition, the controller  2203  further comprises a serial data interface, through which the content data to be displayed on the plurality of display screens  210   1  to  210   N  and the control signal generated by the controller  2203  for controlling the plurality of display screens  210   1  to  210   N  may be transmitted to the plurality of display screens  210   1  to  210   N , to control the plurality of display screens  210   1  to  210   N  to display the respective content data received according to the control signal. Detailed description will be given below in combination with specific embodiments. 
       FIG. 2B  schematically illustrates a block diagram of an electronic label according to another embodiment of the present disclosure. As shown in  FIG. 2B , the driving circuit  220  of the electronic label  20  may further include a repeater  2206  and 2 charger interface  2207 . 
     The repeater  2206  is connected to the communicator  2202  and the power supply circuit  2201 . The repeater  2206  is configured to receive content data to be displayed on the plurality of display screens  210   1  to  210   N  and distribute the content data to the communicator  2202  according to a signal strength between the repeater  2206  and the communicator  2202 . The communicator  2202  is configured to receive the content data from the repeater  2206 . The power supply circuit  2201  is used to supply power to the repeater  2206 . 
     According to the embodiments of the present disclosure, the content data may be received by the repeater  2206  in batch, and distributed according to the signal strength between the repeater  2206  and the communicator  2202 , thereby ensuring a reliable receipt of the content data and reducing power consumption. 
     The charger interface  2207  is configured to charger the electronic label  20 . In some embodiments, the charger interface  2207  is a type C interface. According to the embodiments of the present disclosure, the working duration of the electronic label  20  may be increased and the maintenance cost of the electronic label  20  may be reduced. 
     According to the embodiments of the present disclosure, the communicator  2202  is further configured to receive control instructions form an application installed on a mobile phone. The control instructions may be used to control the at least one of the plurality of display screens  210   1  to  210   N . Referring to  FIG. 2C , the electronic label  201  (the communicator  2202 ) may communicate with the mobile phone  202  (an application), and receive control instructions form the mobile phone  202 . In some embodiments, when there are individual displays that need to be updated separately, they may be updated directly by using the mobile phone  202 . According to the embodiments of the present disclosure, a usage range of the electronic labels may be greatly enlarged. 
     In the embodiment shown in  FIGS. 2A and 2B , the display screens  210   1  to  210   N  may further comprise respective buffers  2101   1  to  2101   N . The buffers  2101   1  to  2101   N  are configured to store the content data received from the controller  2203  to be displayed on the display screens  210   1  to  210   N  respectively. 
     In the embodiment of the present disclosure, the content data to be displayed is transmitted to the plurality of display screens  210   1  to  210   N  through the serial data interface of the controller  2203 . The serial data interface may be a group of data interfaces. A structure of the serial data interface and a connection relationship between the controller  2203  and the plurality of display screens  210   1  to  210   N  through the serial data interface will be described in detail below with reference to the accompanying drawings. 
       FIG. 3  schematically illustrates a structure of a serial data interface of an electronic label according to an embodiment of the present disclosure. As shown in  FIG. 3 , the serial data interface  30  may comprise at least one selection interface, which is used to transmit selection signals CS 1  to CS M  respectively, so as to select at least one of the plurality of display screens  210   1  to  210   N . An interface data width of each of the selection signal interfaces may be 1 bit. In some embodiments, a first level (for example, a high level) may be set as an valid level of the selection signals CS 1  to CS M , that is, when a selection signal is at the first level (for example, the high level), a corresponding display screen is selected. It may be understood by those skilled in the art that a second level (for example, a low level) may also be set as the valid level of the selection signals CS 1  to CS M , that is, when a selection signal is at the second level (for example, the low level), a corresponding display screen is selected. The selected display screen may receive content data and a control signal transmitted by the controller  2203 . The unselected display screens may not receive content data and a control signal transmitted by the controller  2203 . 
     In the example shown in  FIG. 3 , for example, when the display screen  210   1  is selected using the selection signal CS 1 , only the display screen  210   1  may receive content data and a control signal transmitted by the controller  2203  and transmit a signal to the controller  2203 , and remaining unselected display screens (for example, the display screens  210   2  to  210   N ) may not receive content data and a control signal transmitted by the controller  2203 , and may not transmit signals to the controller  2203 . 
     As shown in  FIG. 3 , the selection interfaces through which the selection signals CS 1  to CS M  are transmitted are connected to respective chip selection ports CS of the plurality of display screens  210   1  to  210   N . It should be illustrated that a number M of the selection interfaces may be less than or equal to a number N of the display screens  210   1  to  210   N , that is, M≤N. When the number of the selection interfaces is equal to the number N of the display screens  210   1  to  210   N  (i.e., M=N), the selection interfaces may be directly connected to the respective chip selection ports CS of the display screens in one-to-one correspondence. A scenario where M=N is shown in  FIG. 3 , in which a selection interface through which the selection signal CS M  is transmitted is connected to a chip selection port CS of the display screen  210   N . 
     In some embodiments, when the number M of the selection interfaces is less than the number N of the display screens  210   1  to  210   N , each of the selection interfaces may not be directly connected to a chip selection port of one of the display screens. In this case, the following methods may be used to realize connection between the selection interfaces and the display screens and the selection of the display screens. 
     For example, when the number M of the selection interfaces is less than the number N of the display screens  210   1  to  210   N , the selection signals CS 1  to CS M  in the selection interfaces may be encoded and decoded to generate selection signals corresponding to the respective display screens. For example, if the number of the selection interfaces is 3, three selection signals CS 1  to CS 3  in the three selection interfaces may be binary-coded to further obtain eight selection signals (which may be denoted as CS′ 1 , CS′ 2 , CS′ 3 , CS′ 4 , CS′ 5 , CS′ 6 , CS′ 7  and CS′ 8  respectively). The above eight selection signals are obtained through a decoding process by adding a decoder, which may realize selection of eight display screens. This helps to reduce a number of ports of the controller  2203 , thereby driving more display screens. 
     As another example, when the number M of the selection interfaces is less than the number N of the display screens  210   1  to  210   N , processing may be performed based on actual situations. If at least some of the plurality of display screens  210   1  to  210   N  always display the same content, the plurality of display screens  210   1  to  210   N  may be divided into several groups, display screens in each group display the same content, and display screens in different groups may display different content. Thereby, the same selection interface may be connected to all display screens in the same group at the same time, so that these display screens may be selected at the same time. In this way, more display screens may be selected using fewer selection signals while simplifying a transmission operation of the content data. 
     As shown in  FIG. 3 , the serial data interface may further comprise a clock interface. The clock interface may transmit a synchronization clock signal CLK to the plurality of display screens  210   1  to  210   N . The synchronization clock signal CLK is used for synchronization between data transmission and data reception between the controller  2203  and the plurality of electronic screens  210   1  to  210   N . According to some embodiments, the data transmission and the data reception may be set to be performed synchronously on a rising edge of the synchronization clock signal CLK. It may be understood by those skilled in the art that the data transmission and the data reception may be set to be performed synchronously on a falling edge of the synchronization clock signal CLK. 
     As shown in  FIG. 3 , the clock interface is connected to the corresponding ports (for example, CLK ports of serial peripheral interfaces SPI) of all the plurality of display screens  210   1  to  210   N  at the same time. For example, an interface data width of the clock interfaces is also 1 bit. 
     As shown in  FIG. 3 , the serial data interface may further comprise a data interface DATA, which is a serial data interface having an interface data width of 1 bit. The data interface DATA is configured to serially transmit the content data to be displayed on the plurality of display screens  210   1  to  210   N  and the control signal under synchronous control of the synchronization clock signal CLK. 
     As shown in  FIG. 3 , the data interface DATA may be connected to the corresponding ports of all the plurality of display screens  210   1  to  210   N  at the same time, for example, Master Output Slave Input (MOSI) ports of the serial peripheral interfaces SPI. It should be illustrated that only the MOSI ports of the serial peripheral interfaces SPI, instead of the overall structure of the SPIs, are shown on the respective display screens in  FIG. 3 . The controller  2203  may further implement conversion from parallel data to serial data in the driving circuit  220 . In addition, built-in logics in the serial peripheral interfaces SPI for the display screens may complete the conversion from serial data to parallel data in the plurality of display screens  210   1  to  210   N . In addition, since the data interface DATA has a function of transmitting both the content data and the control signal, different type flags need to be set to distinguish the content data and the control signal. The controller  2203  may add the type flags in the data to be transmitted according to different types of the data. In addition, when the controller  2203  transmits the content data and the control signal to the display screens, the controller  2203  firstly transmits the type flags. 
     The controller  2203  may be implemented by a general-purpose element, for example, a microprocessor, a microcontroller, a Field Programmable Gate Array (FPGA) etc., and the embodiments of the present disclosure are not limited thereto. The content data and the control signal are transmitted by using a group of serial data interfaces comprising at least one selection interface, a clock interface, and a data interface, which may effectively reduce a cost of the driving circuit while simplifying the operation. 
       FIG. 4  schematically illustrates a flowchart of a method for driving an electronic label according to an embodiment of the present disclosure. As shown in  FIG. 4 , the driving method may comprise the following steps. 
     In step S 410 , a communicator receives content data to be displayed on a plurality of display screens. 
     In step S 420 , the controller transmits the content data to be displayed on the plurality of display screens and a control signal generated by the controller for controlling the plurality of display screens to the plurality of display screens through a serial data interface respectively. 
     In step S 430 , the plurality of display screens display the respective content data received according to the control signal. 
     According to the above embodiments, the serial data interface of the controller  2203  may comprise a clock interface, a data interface, and at least one selection interface. Therefore, transmitting, by the controller  2203 , the content data to be displayed on the plurality of display screens and the control signal generated by the controller for controlling the plurality of display screens to the plurality of display screens through the serial data interface respectively may specifically comprise: selecting at least one of the plurality of display screens through the at least one selection interface, transmitting a synchronization clock signal to the plurality of display screens through the clock interface, and serially transmitting the content data to be displayed on the plurality of display screens and the control signal to the plurality of display screens through the data interface under synchronous control of the synchronization clock signal. 
     According to the embodiments of the present disclosure, in step S 410 , the content data to be displayed on the plurality of display screens is received by the repeater  2206 , and is distributed to the communicator  2202  according to a signal strength between the repeater  2206  and the communicator  2202 . 
     According to the embodiments of the present disclosure, the communicator  2202  may further receive control instructions form an application installed on a mobile phone. The control instructions may be used to control the at least one of the plurality of display screens  210   1  to  210   N . 
     A process of driving the plurality of display screens  210   1  to  210   N  by the driving circuit  220  in order to display the same content or different content on the plurality of display screens  210   1  to  210   N  will be described in detail below with reference to  FIGS. 4 to 6B . 
     In some embodiments, when the content data to be displayed on the plurality of display screens are the same, in response to the content data to be displayed on the plurality of display screens being the same, the controller  2203  may select the plurality of display screens through the at least one selection interface at the same time. The above data transmission process will be described in detail below with reference to  FIGS. 5A and 5B . Here,  FIG. 5A  schematically illustrates a flowchart of a method for driving an electronic label according to an example of the present disclosure, and  FIG. 5B  schematically illustrates a signal timing diagram of the exemplary method shown in  FIG. 5A , for example. 
     As shown in  FIG. 5A , the exemplary method may comprise the following steps. 
     In step S 510 , serial data signals in a serial data interface are initialized. For example, selection signals CS 1  to CS M  may be set to a second level (for example, a low level shown in  FIG. 5B ), so that the display screens are not selected. The data interface may be set to be in a high impedance state. Data transmission may be set to be performed on, for example, a rising edge of a synchronization clock signal CLK. It may be understood by those skilled in the art that the data transmission may also be set to be performed on, for example, a falling edge of the synchronization clock signal CLK. 
       FIG. 5B  schematically illustrates a signal timing diagram of the exemplary method shown in  FIG. 5A , and description will be made by taking two display screens  210   1  and  210   2  being connected as an example. As shown in  FIG. 5B , in an initial period T 0 , the controller  2203  initializes a serial data interface. Here, a selection signal CS 1  connected to the display screen  210   1  and a selection signal CS 2  connected to the display screen  210   2  are set to a low level at the same time. A data interface is set to be in a high impedance state. 
     It should be illustrated that before the serial data signals are initialized, other modules of the driving circuit  220  may also be initialized. For example, a current ambient temperature may be acquired through a temperature sensor module (included in the display screens or outside the display screens) during the initialization phase, and then data of the ambient temperature is transmitted to the display screens as a control signal parameter. This is because for the electronic label having electronic ink screens as the display screens, different display modes may be selected according to the current ambient temperature, so that the content data is displayed more clearly. 
     Next, in step S 520 , all the display screens  210   1  to  210   N  are selected by setting all the selection signals CS 1  to CS M  to a valid level, that is, a first level (for example, a high level shown in  FIG. 5B ). 
     As shown in  FIG. 5B , at a certain time after the first period T 0 , the controller  2203  sets the selection signal CS 1  connected to the display screen  210   1  and the selection signal CS 2  connected to the display screen  210   2  to a high level at the same time, and thereby the display screens  210   1  and  210   2  are selected at the same time. 
     Then, in step S 530 , the content data is serially transmitted through the data interface DATA under control of the synchronization clock signal CLK. 
     As shown in  FIG. 5B , the content data is transmitted during a first period T 1 . In addition to valid content data to be displayed, the content data may also comprise a type flag and an end flag. As described above, the type flag is used to indicate whether the transmitted data is content data or a control signal. In this example, the type flag indicates that the transmitted data is content data. The end flag is used to indicate the end of the data transmission. The first period T 1  comprises duration of several synchronization clock signals, wherein the valid content data is transmitted on a rising edge of each of the synchronization clock signal pulses, and the display screens  210   1  and  210   2  receive the valid content data at the same time, and store the received valid content data in respective buffers. A length of the first period T 1  is determined by a data amount of the valid content data to be transmitted. 
     Then, in step S 540 , the controller  2203  acquires state signals fed back by the display screens  210   1  and  210   2  during a preset time period. Each of the state signals indicates whether a corresponding display  210   1  or  210   2  has completed data transmission and is ready for refreshing display. For example, when the state signal from the display screen  2101  is at the first level (for example, the high level shown in  FIG. 5B ), it indicates that the display screen  210   1  has completed data transmission, and may refresh the display. When the state signal from the display screen  210   1  is at the second level (for example, the low level shown in  FIG. 5B ), it indicates that the display screen  210   1  has not completed data transmission, and may not refresh the display. 
     As shown in the example of  FIG. 5B , the state signal from the display screen  210   1  is a state signal  1  which, for example, is transmitted to the controller  2203  through a state signal output port of the display screen  210   1  connected to the controller  2203 . For example, a state signal output port may be a port of one of the plurality of display screens  210   1  to  210   N , and is mainly used to feed back a state of the display screen. The state signal of the display screen  210   2  is a state signal  2 , which is transmitted to the controller  2203  through a state signal output port of the display screen  210   2  connected to the controller  2203 . The display screen  210   1  sets the state signal  1  to a high level after completing the data transmission with the controller  2203 . The display screen  210   2  sets the state signal  2  to a high level after completing the data transmission with the controller  2203 . The controller  2203  collects the state signal  1  and the state signal  2  during a second period T 2 . 
     Next, in step S 550 , the controller  2203  determines whether all state signals are at a high level, and if so, in step S 560 , the controller  2203  serially transmits the control signal through the data interface DATA under control of the synchronization clock signal CLK. 
     As shown in  FIG. 5B , when the collected state signal  1  and state signal  2  are both at a high level, the controller  2203  determines that the display screens  210   1  and  210   2  are ready for refreshing display. Therefore, during a third period T 3 , the control signal is transmitted to the display screens  210   1  and  210   2  at the same time. The control signal may comprise a refresh signal for refreshing the display. In some embodiments, the control signal may further comprise temperature data and other control parameters. Similarly to a data format of the content data, the control signal comprises a valid control signal, a type flag, and an end flag. The type flag is used to indicate that the transmitted data is a control signal, and the end flag is used to indicate the end of data transmission. The third period T 3  may comprise duration of several synchronization clock signals. The control signal is transmitted on a rising edge of each of the synchronization clock signal pulses, and the display screens  210   1  and  210   2  receive the control signal at the same time. Similarly, a length of the third period T 3  is determined by a data amount of control signals to be transmitted. 
     After the control signal is transmitted completely, the controller  2203  sets the selection signals CS 1  and CS 2  to a low level, and the data transmission between the controller  2203  and the display screens  210   1  and  210   2  ends. 
     Next, in step S 570 , the display screens  210   1  and  210   2  refresh the display respectively according to the received control signal. When the display screens  210   1  and  210   2  refresh the display, the display screens  210   1  and  210   2  reset the respective state signal  1  and state signal  2  to a low level at the same time, as shown in  FIG. 5B . 
     If the controller  2203  determines in step S 550  that not all the state signals are at a high level, the controller  2203  returns to step S 530  to retransmit the content data. 
     For example, if the state signal  2  does not become a high level during the second period T 2  in  FIG. 5B , the controller  2203  may retransmit the content data instead of the control signal during the third period T 3 . A process of transmitting the content data is as described in step S 530 , and will not be repeated here. 
     In addition, it may be understood by those skilled in the art that the controller  2203  may select to retransmit the content data to the display screen  210   2  only during the third period T 3 . At this time, the controller  2203  needs to firstly set the selection signal CS 1  to a low level before transmitting the content data, that is, the display screen  210   1  does not receive the content data again. Then, when the control signal needs to be transmitted to the display screens  210   1  and  210   2 , the selection signal CS 1  is set to a high level before the control signal is transmitted. 
     According to the embodiments of the present disclosure, when the same content is to be displayed on the plurality of display screens  210   1  to  210   N , the content data is transmitted to all the plurality of display screens  210   1  to  210   N  through the same synchronization clock signal interface and content/control data signal interface at the same time, which reduces a cost of the system while simplifying the operation of driving the plurality of display screens  210   1  to  210   N . 
     In some other embodiments, when the content data to be displayed on the plurality of display screens is different, in response to the content data to be displayed on the plurality of display screens being different, the controller  2203  may sequentially selects at least one of the plurality of display screens through the at least one selection interface. The above data transmission process will be described in detail below with reference to  FIGS. 6A and 6B . Here,  FIG. 6A  schematically illustrates a flowchart of a method for driving an electronic label according to another example of the present disclosure, and  FIG. 6B  schematically illustrates a signal timing diagram of the exemplary method shown in  FIG. 6A , for example. 
     As shown in  FIG. 6A , the exemplary method may comprise the following steps. 
     In step S 610 , serial data signals in a serial data interface are initialized. An operation in this step is similar to that in step S 510 , and the initialization operation is performed during an initial period T 0 ′ shown in  FIG. 6B , and will not be repeated here. 
     Next, in step S 620 , at least one of a plurality of display screens  210   1  to  210   N  are selected by setting at least one of selection signals CS 1  to CS M  to a valid level, that is, a first level (for example, a high level shown in  FIG. 6B ). 
     As shown in  FIG. 6B , at a certain time after the initial period T 0 ′, the controller  2203  sets the selection signal CS 1  connected to the display screen  210   1  to a high level, and thereby the display screen  210   1  is selected. The selection signal CS 2  connected to the display screen  210   2  remains at a low level, and thereby the display screen  210   2  is not selected. 
     Then, in step S 630 , the content data is serially transmitted through a data interface DATA under control of a synchronization clock signal CLK. 
     As shown in  FIG. 6B , since only the display screen  210   1  is selected, during a first period T 1 ′, only the display screen  210   1  may receive the content data transmitted by the controller  2203 , and the display screen  210   2  may not receive the content data transmitted by the controller  2203 . The content data comprises valid content data, a type flag, and an end flag. The type flag is used to indicate that the transmitted data is content data, and the end flag is used to indicate the end of data transmission. The first period T 1 ′ may comprise duration of several synchronization clock signal pulses. The content data is transmitted on a rising edge of each of the synchronization clock signal pulses, and the display screen  210   1  receives the content data and stores the received content data in its own buffer  210   1 . A length of the first period T 1 ′ may be determined by a data amount of the content data to be displayed on the display screen  210   1 . 
     Then, in step S 640 , the controller  2203  acquires a state signal fed back by the selected at least one display screen during a preset time period. The state signal indicates whether the selected at least one display screen has completed data transmission and is ready for refreshing the display. 
     As shown in  FIG. 6B , a state signal of the display screen  210   1  is a state signal  1 , which is transmitted to the controller  2203  through a state signal output port of the display screen  210   1  connected to the controller  2203 . The display screen  210   1  sets the state signal  1  to a high level after completing the data transmission with the controller  2203 . The controller  2203  collects the state signal  1  during a second period T 2 ′. 
     Next, in step S 650 , the controller  2203  determines whether all the state signals of the selected at least one display screen are at a high level, and if so, in step S 660 , the controller  2203  transmits a control signal serially through the data interface DATA under control of the synchronization clock signal CLK. 
     As shown in  FIG. 6B , when the collected state signal  1  is at a high level, the controller  2203  determines that the display screen  210   1  is ready for refreshing the display. Therefore, during a third period T 3 ′, the control signal is transmitted to the display screen  210   1 . The definition of the control signal has been described in the above embodiment, and will not be repeated here. 
     After the control signal has been transmitted, the controller  2203  sets the selection signal CS 1  to a low level, and the data transmission between the controller  2203  and the display screen  210   1  ends. 
     If the controller  2203  determines in step S 650  that not all the state signals of the selected at least one display screen are at a high level, for example, if the controller  2203  selects two display screens (for example, the display screen  210   1  and another display screen other than the display screen  210   2 ) in step S 620 , and the controller  2203  determines that the state signal  1  of the display screen  210   1  is not at a high level, the controller  2203  returns to step S 630  to retransmit the content data. A process of retransmitting the content data has been described in the above embodiments, and will not be repeated here. 
     Next, in step S 670 , the selected at least one display screen refreshes the display according to the received control signal. 
     As shown in  FIG. 6B , during a fourth time period T 4 , the display screen  210   1  refreshes its display according to the received control signal, while the display screen  210   2  does not refresh the display. As shown in  FIG. 6B , the display screen  2101  resets its state signal  1  to a low level at the same time. 
     Next, in step S 680 , the controller  2203  determines whether all the content data has been transmitted. If a determination result is no, it indicates that there is content data which needs to be transmitted to other display screens, and therefore the procedure returns to step S 610  to repeat steps S 610  to S 670 , and the operation ends until all the content data has been transmitted. 
     As shown in  FIG. 6B , during a fifth period T 5 , the controller  2203  performs an initialization operation on the serial data signals in the serial data interface again, and selects the display screen  210   2  by setting the selection signal CS 2  to a high level. In addition, it should be illustrated that, in one example, after the controller  2203  completes transmission of the control signal to the display screen  210   1 , and has sets a corresponding selection signal (for example, CS 1 ) to an invalid level, and it is determined that the transmission of the content data has not been completed, transmission of the content data to a next display screen may be started. Therefore, in  FIG. 6B , although the fifth period T 5  is shown after the fourth period T 4 , according to the embodiment of the present disclosure, the fifth period T 5  and an execution time of subsequent operations may be concurrent with the fourth period T 4 . 
     According to the embodiments of the present disclosure, when different content is to be displayed on the plurality of display screens  210   1  to  210   N , the content data is sequentially transmitted to all the plurality of display screens  210   1  to  210   N  through the same synchronization clock signal interface and the content/control data signal interface, which may reduce a cost of the system, improve the efficiency of transmission between the controller and the display screens, and simplify the operation of driving the plurality of display screens. 
     It should be illustrated that, in the above description, the technical solutions according to the embodiments of the present disclosure are shown by way of example only, but it does not mean that the embodiments of the present disclosure are limited to the above steps and structures. Where possible, the steps and structures may be adjusted and selected as needed. Therefore, certain steps and units are not elements necessary to implement the general inventive concept of the embodiments of the present disclosure. 
     The present disclosure has been described so far in connection with the preferred embodiments. It should be understood that those skilled in the art can make various other changes, substitutions, and additions without departing from the spirit and scope of the embodiments of the present disclosure. Therefore, the scope of the embodiments of the present disclosure is not limited to the specific embodiments described above, but should be defined by the appended claims.