EPD module and electronic shelf label

Abstract

According to the present application, a solar cell module, a light intensity detection module, and a display module are integrated into an integrated EPD module, and all electronic components are integrated on a TFT array and a printed circuit board (PCB). The display module integrates the solar cell module; an NFC antenna is integrated on the PCB and can replace the traditional antenna on the PCB. In the present application, an electricity usage relationship among the solar cell module, an energy storage module, and a load is managed by means of a specific charging / discharging management module and a matching charging / discharging management method, thereby achieving intelligent electricity distribution on the basis of the usage status.

Description

EPD Module and Electronic Price Tag

[0001] Related applications

[0002] This application claims priority to Chinese Patent Application No. 202311650058.6, filed on December 4, 2023, and incorporates the entire contents of the aforementioned patent application as part of this application. Technical Field

[0003] This application relates to the field of electronic shelf label technology, and in particular to EPD modules and electronic shelf labels. Background Technology

[0004] Electronic shelf labels (ESLs), also known as electronic shelf labels, are electronic display devices with information transmission and reception capabilities. They are primarily used in supermarkets, convenience stores, pharmacies, and other similar establishments to display price information. ESLs are placed on shelves and serve as electronic displays that replace traditional paper price tags. Each ESL connects to the store's computer database via a wired or wireless network to receive the latest product information and display it on its screen. ESLs integrate the shelf space into a computer program (specifically, they remotely interact with the product identification on the shelf and the backend product management system, including information such as price, category, inventory, and country of origin). This expands the functionality of ordinary price tags, eliminates the need for manual price tag changes, and ensures price consistency between the checkout counter and the shelf.

[0005] The main functions of electronic shelf labels are to enable screen-based price changes and synchronized management of front-end and back-end information. Key components include display devices, power supply devices, NFC (Near Field Communication) components, and main control chips. The display devices are primarily electronic ink / electronic paper displays (EPDs), and the power supply devices are mainly primary and secondary batteries. In addition, existing electronic shelf labels also incorporate solar cells, photosensors, and other components.

[0006] Chinese patent CN202220239095.2 discloses a solar-powered electronic shelf label, including a back cover with a solar panel. A wiring groove extending to the front end face of the back cover is formed therein, and wires are arranged within the wiring groove. The solar panel is connected to a control board via the wires, and the control board is connected to a screen. This patent solves the technical problem of limited battery capacity affecting the lifespan of electronic shelf labels by introducing a solar panel.

[0007] Chinese patent CN202011461029.1 discloses an electronic tag, an electronic price tag, and a control method thereof, comprising: an electronic tag body, a display unit, an illumination unit, a first acquisition unit, and a control unit disposed on the electronic tag body; the first acquisition unit is configured to acquire the light intensity of the environment in which the electronic tag body is located to obtain the current light intensity; the control unit is configured to determine whether the current light intensity is lower than a preset light intensity, so as to initiate an illumination command when the current light intensity is lower than the preset light intensity. This solution, through light intensity judgment, enables the electronic tag to display the tag content even in low-light conditions, thereby improving the ease of use of the electronic tag.

[0008] However, in existing technologies, solar cells or photosensitive devices are separate components, electrically connected and integrated via printed circuit boards. This severely limits the miniaturization, reliability, manufacturability, and low cost of solar-powered electronic shelf labels. Furthermore, existing electronic shelf labels using rechargeable batteries suffer from poor charge and discharge management, lack over-discharge resistance, and have poor maintainability.

[0009] Summary of the Invention

[0010] To address the shortcomings of existing technologies, this application provides an EPD module and electronic price tag, which solves the problems of miniaturization, reliability, manufacturability and low cost due to the use of discrete device integration in existing technologies, as well as low charge and discharge management level, lack of over-discharge resistance and poor maintainability.

[0011] According to an embodiment of this application, an EPD module includes a display component, a solar cell component, a printed circuit board, and an energy storage component;

[0012] The display component includes a substrate, a thin film transistor (TFT) array, an electronic paper film (FPL), and a cover plate stacked sequentially. The TFT array is provided with a driving circuit corresponding to the FPL.

[0013] The solar cell assembly includes solar cells, which are disposed on the outer surface of the cover plate and the area covered by the solar cells does not overlap with the display area of ​​the FPL. The electrodes of the solar cells are electrically connected to the TFT array.

[0014] The printed circuit board is electrically connected to the TFT array, and a control circuit is provided on the printed circuit board; and

[0015] The energy storage component is used to receive energy provided by the solar cell module and output electrical energy, and is electrically connected to the printed circuit board.

[0016] This application also proposes an electronic price tag, including the aforementioned EPD module.

[0017] Compared with the prior art, this application has the following beneficial effects:

[0018] 1. This application is a highly integrated one-piece EPD module, which integrates all electronic components onto the TFT array and printed circuit board. There are no additional independent devices, and there is no need to connect and integrate circuits one by one through the circuit board. This greatly improves the miniaturization of electronic price tags. At the same time, the highly integrated product also reduces the need for additional spare parts, thereby improving production efficiency and reducing cost requirements.

[0019] 2. The EPD module of this application integrates solar cell modules, which can avoid the complex and unreliable electrical connection methods such as leads of separate solar cell devices in traditional photovoltaic electronic price tag products, which is conducive to improving product reliability, promoting product miniaturization and low cost. Attached Figure Description

[0020] Figure 1 is a schematic diagram of the module architecture of an embodiment of this application.

[0021] Figure 2 is a schematic diagram of the module in an embodiment of this application.

[0022] Figure 3 is a plan view of the solar cell and photosensitive sensor device according to an embodiment of this application.

[0023] Figure 4 is a planar schematic diagram of the module assembly process according to an embodiment of this application.

[0024] Figure 5a is a cross-sectional view of B-B' of an embodiment of this application.

[0025] Figure 5b is a longitudinal cross-sectional view of a conventional area module according to an embodiment of this application.

[0026] Figure 6a is a cross-sectional view along line C-C' of an embodiment of this application.

[0027] Figure 6b is a longitudinal cross-sectional view of the solar cell module according to an embodiment of this application.

[0028] Figure 7a is a cross-sectional view of D-D' of an embodiment of this application.

[0029] Figure 7b is a longitudinal cross-sectional view of the photosensitive sensor area module according to an embodiment of this application.

[0030] Figure 8 is a schematic diagram of the charging and discharging module architecture according to an embodiment of this application.

[0031] Figure 9 is a flowchart of the charging and discharging module management process according to an embodiment of this application.

[0032] In the above figures: Driver IC is equivalent to IC, i.e., driving circuit; EPD_bus is equivalent to EPD bus; Solar is equivalent to solar cell; TFT substrate is equivalent to the substrate and TFT array as a whole. Detailed Implementation

[0033] The technical solutions in this application will be further described below with reference to the accompanying drawings and embodiments.

[0034] As shown in Figure 1, this application proposes an EPD module, including an electronic paper screen display component, a solar cell component, a printed circuit board, and an energy storage component.

[0035] As shown in Figures 2, 3, and 4, in this embodiment, the display component includes a substrate, a thin-film transistor (TFT) array, an electronic paper film (FPL), and a cover plate stacked sequentially. It should be noted that the central area enclosed by the border on the FPL surface is the display area of ​​the FPL, used to display information such as prices on price tags. In this embodiment, the outer side of the FPL is sealed with adhesive, thus, together with the cover plate, enclosing the FPL on the TFT array and preventing dust and other impurities from entering the FPL surface or between the FPL and the TFT array, affecting the display function. Specifically, this embodiment uses a cover plate made of polystyrene (PS) material. Optionally, the substrate can be a glass substrate or a flexible PI substrate; in this embodiment, a flexible PI substrate can be used to improve the overall flexibility and bending resistance of the product.

[0036] Printed circuit boards include one or a combination of FPC (Flexible Printed Circuit) and PCB (Printed Circuit Board). In this embodiment, a flexible printed circuit board (FPC) can be used to improve product flexibility. While being bendable, the FPC can integrally carry various circuit components and integrate other electronic devices, thus simplifying the manufacturing process. A strip structure extends from one side of the FPC, overlapping with the edge of the TFT array and forming an electrical connection. A protective adhesive is also applied over the overlapping connection between the FPC and the TFT array, strengthening the connection and protecting the connection from external forces that could damage its stability. Simultaneously, this strip structure can be bent so that the FPC can be stacked on the outer side of the substrate after bending, and the strip structure is completely covered by the substrate, thus preventing an increase in area during packaging and further reducing the product size. The relatively rigid substrate also protects the flexible FPC. A control circuit is provided on the FPC. In this embodiment, the control circuit includes the control circuitry for the ESL main circuit and other electronic devices, acting as a processor (MCU) to manage the circuit program.

[0037] The TFT array features a corresponding driving circuit for the FPL, which is electrically connected to the ESL main circuit on the FPC via the EPD bus. To further enhance product integrity, the TFT array also integrates a temperature acquisition circuit and an NFC antenna, which is electrically connected to the TFT array. Replacing the traditional separate antenna assembly on the PCB board with an integrated NFC antenna not only improves the performance of related antennas and reduces costs but also shrinks the device size.

[0038] Correspondingly, the FPC is also equipped with a backup NFC antenna, a radio frequency antenna, and an LED (Light Emitting Diode), the first two of which are electrically connected to the FPC. The NFC antenna on the FPC not only serves as a backup but can also work with the NFC near-field coupling power supply to provide power when lighting conditions are poor or the solar cells are insufficient. The NFC antenna and the radio frequency antenna can also work together to transmit signals to the central management computer, updating shelf information in real time.

[0039] In this embodiment, the solar cell module includes solar cells, which are disposed on the outer surface of the cover plate, and the area covered by the solar cells does not overlap with the display area of ​​the FPL. The materials of the solar cells include perovskite, organic photovoltaic (OPV), amorphous silicon, or dye-sensitized solar cells (DSSC). In this embodiment, OPV or perovskite can be used to improve its impact resistance and shatter resistance, preventing damage to the outer solar cells from accidental impacts.

[0040] Meanwhile, to improve applicability, the solar cell can be a single solar cell or a combination of multiple solar cells connected in series, parallel, or a series-parallel configuration to meet various needs. In terms of shape, the solar cell can be U-shaped, rectangular, strip-shaped, L-shaped, or other structures, preferably adapted to the specific size of the solar cell and the shape of the substrate. As shown in Figure 3, as an option, this embodiment uses a right-angled U-shaped structure to match the substrate shape and avoids the connection area of ​​the FPC from the opening. In this embodiment, adhesive bonding, hot-pressing fusion, and UV (Ultraviolet) curing are used to integrate the solar cell with the display component, making it perfectly wrap around the perimeter of the FPL. Except for one opening end, it covers the entire area from the boundary of the FPL to the edge of the substrate, thereby maximizing the use of the substrate surface space and improving light energy conversion efficiency.

[0041] In this embodiment, the energy storage component is a secondary battery, which can be mounted on an FPC or TFT. In this embodiment, it is mounted on the FPC to form an integrated structure and is electrically connected to the FPC. Traditional ternary lithium-ion batteries and lithium iron phosphate batteries, after prolonged deep over-discharge, experience irreversible and significant deterioration in their capacity, current output capability, and self-discharge rate, resulting in extremely poor maintainability for electronic shelf label products. Therefore, the energy storage component in this embodiment uses a lithium titanate battery, which has advantages such as small size, resistance to over-discharge, anti-gas buildup, high cycle life, high charge / discharge rate, and high safety. Lithium titanate batteries specifically include ultra-thin pouch lithium titanate batteries, cylindrical lithium titanate batteries, and coin-type lithium titanate batteries. Optionally, this embodiment uses ultra-thin pouch lithium titanate batteries or small-sized coin-type batteries to complement the overall flexible structure.

[0042] Optionally, this embodiment also includes a light intensity detection component. Specifically, the light intensity detection component includes a photosensor, which is disposed in an area not covered by the FPL on the working surface of the TFT array; in this embodiment, it is disposed on one side of the opening of the U-shaped solar cell. The light intensity detection component also includes a sampling amplification circuit and an AD conversion circuit disposed on the FPC. The photosensor converts ambient light into an electrical signal through photoelectric conversion, and the collected electrical signal is transmitted to the control circuit via the sampling amplification circuit and the AD conversion circuit. After processing by the MCU in the ESL main circuit, the illuminance is detected, thereby better cooperating with the use of the solar cell module. At the same time, the light intensity detection component can also be used in conjunction with LED lights through the ESL main circuit to turn the lights on or off in different lighting conditions, better displaying shelf information.

[0043] As shown in Figures 5a-7b, regarding the specific circuit connection method, the solar cell directly leads out its conductive electrodes through leads, flexible circuit boards, and copper foil, and is electrically connected to the TFT array through methods such as silver paste dot connection, welding, pressing, and ion-blast bonding. This provides power to the driving circuit on the TFT array and, through the electrical connection between the TFT array and the FPC, powers the ESL main circuit and energy storage components on the FPC. Optionally, the FPL is electrically connected to the TFT array through a silver paste dot structure and is electrically connected to the driving circuit through the TFT array. The TFT array is provided with conductive electrodes for electrical connection with the solar cell, and these conductive electrodes are electrically connected to the conductive electrodes on the solar cell through silver paste dots. The silver paste dot electrical connection method makes the integrated module structure in this embodiment more compact and has higher reliability.

[0044] In a more specific embodiment, the FPL and TFT array are simultaneously welded via two silver paste points; the two conductive electrodes on the solar cell are simultaneously welded to the conductive electrodes of the TFT array via two silver paste points; and the photosensitive sensor is welded to the TFT array via independently set silver paste points. As shown in Figures 2, 3, and 4, the FPL and TFT array are simultaneously welded via silver paste points 11 and 12; the conductive electrodes 21 and 22 on the solar cell are simultaneously welded to the electrode regions 21 and 22 (i.e., the conductive electrodes on the TFT array) on the TFT array via silver paste points 21 and 22; and the photosensitive sensor is welded to the electrode region 3 on the TFT array via silver paste point 3. This three-step welding process sequentially completes the welding of the FPL, solar cell, and photosensitive sensor, eliminating the need to weld each solder point individually, thus improving processing efficiency and simplifying the process.

[0045] As shown in Figure 8, the EPD module in this embodiment also includes a charge / discharge management module. The charge / discharge management module is integrated on the FPC and is electrically connected to the solar cell module and / or NFC antenna, energy storage module, control circuit, and display module, and can also be electrically connected to a photosensor. The solar cell module and / or NFC antenna convert solar energy or near-field coupling energy into electrical energy, which is then used to charge the energy storage module or supply power to the load through the charge / discharge management.

[0046] It should be noted that in this embodiment, the EPD module has a standby state and an operating state. In the standby state, the FPL screen does not need to refresh its display information; only some electronic components require a small current to maintain operation. In the operating state, the FPL screen refreshes its display information normally, requiring the drive circuit for control, and the ESL main circuit on the FPC also needs to operate normally, thus requiring a large current supply to support its operation. Therefore, in this embodiment, when the EPD module is in standby state, the solar cells provide the small current required for standby to the TFT array, drive circuit, ESL main circuit on the FPC, and other electronic devices; excess power is stored in the energy storage device. When the EPD module is in operating state, the energy storage device outputs a large current to the loads on the FPC and TFT array to maintain their normal operation.

[0047] As shown in Figure 9, the corresponding charging and discharging management method of the above-mentioned charging and discharging management module includes the following steps:

[0048] S1, Charge / Discharge Working Mode: Allows the energy storage components to charge and discharge, and allows the solar cells and / or NFC antenna to directly power the load;

[0049] S2. When the voltage of the energy storage component is greater than or equal to the overcharge voltage, it enters the overcharge protection mode: the energy storage component is prohibited from charging but the energy storage component is allowed to output power (e.g., electrical energy), and the solar cell and / or NFC antenna are allowed to directly power the load; otherwise, it enters the charge and discharge working mode from the overcharge protection mode.

[0050] S3. When the voltage of the energy storage component is less than or equal to the over-discharge voltage, it enters the over-discharge protection mode: the power output of the energy storage component is prohibited (for example, the energy storage component is used as a power source to output electrical energy), and the solar cell module and / or NFC antenna are allowed to use the electrical energy converted from solar energy or near-field coupling energy to charge the energy storage component; otherwise, it enters the charge and discharge working mode from the over-discharge protection mode.

[0051] S4. After entering the over-discharge protection mode and passing the standby buffer time, the charge and discharge management module enters the deep sleep standby state. Optionally, the standby buffer time is 0.5-2s. In this embodiment, it is specifically set that the charge and discharge management module enters the deep sleep standby state 1s after entering the over-discharge protection mode.

[0052] S5. When the following conditions are met simultaneously: the power supply of the solar cell module or NFC antenna is greater than the wake-up power, and the energy storage module is not in over-discharge protection mode, the power input triggers wake-up and ends the deep sleep standby state.

[0053] S6. When the voltage of the energy storage component is greater than the minimum output voltage, it enters the charging and discharging working mode.

[0054] Alternatively, in this embodiment, no voltage-to-current conversion device is required between the energy storage component and the load. The power output of the energy storage component can be achieved through the operation of the circuit switches on the FPC. By controlling the maximum output voltage of the solar cell module or the maximum output voltage of the coupled power supply formed by the NFC antenna, without a voltage-to-current conversion device, the energy storage component can be charged using an external power source through the operation of the circuit switches on the TFT array and the FPC.

[0055] By using specific charge and discharge management modules and corresponding charge and discharge management methods to manage the power consumption relationship between solar cell modules, energy storage modules and loads, it can intelligently allocate power usage and has reliable overcharge and over-discharge protection functions. This can effectively ensure the working status of energy storage modules, extend their service life, improve equipment reliability, and facilitate management and maintenance.

[0056] This embodiment also includes an electronic shelf label, comprising the aforementioned EPD module and charge / discharge management module, and managed using the aforementioned charge / discharge management method. This results in an electronic shelf label product characterized by miniaturization, high reliability, highly automated production, and low cost, while also facilitating the management and maintenance of the electronic shelf label.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made to the technical solutions of this application without departing from the spirit and scope of the technical solutions of this application, and all such modifications and sub-combinations should be covered within the scope of the claims of this application.

Claims

1. An EPD module, characterized in that: This includes display components, solar cell modules, printed circuit boards, and energy storage components; The display component includes a substrate, a thin-film transistor (TFT) array, an electronic paper film (FPL), and a cover plate stacked sequentially. The TFT array is provided with a driving circuit corresponding to the FPL. The solar cell assembly includes solar cells, which are disposed on the outer surface of the cover plate and the area covered by the solar cells does not overlap with the display area of ​​the FPL. The electrodes of the solar cells are electrically connected to the TFT array. The printed circuit board is electrically connected to the TFT array, and a control circuit is provided on the printed circuit board; and The energy storage component is used to receive energy provided by the solar cell module and output electrical energy, and is electrically connected to the printed circuit board.

2. An EPD module as described in claim 1, characterized in that: The printed circuit board includes one or a combination of FPC and PCB.

3. An EPD module as described in claim 1, characterized in that: The TFT array is also equipped with an NFC antenna, which is electrically connected to the TFT array.

4. An EPD module as described in claim 1, characterized in that: The materials of the solar cells include perovskite, organic solar cells (OPV), amorphous silicon, or dye-sensitized solar cells (DSSC).

5. An EPD module as described in claim 1, characterized in that: The printed circuit board is also equipped with a spare NFC antenna and a radio frequency antenna, both of which are electrically connected to the printed circuit board.

6. An EPD module as described in claim 1, characterized in that: The energy storage component includes a lithium titanate battery.

7. An EPD module as described in claim 1, characterized in that: The TFT array is provided with a conductive electrode for electrical connection with the solar cell. This conductive electrode achieves electrical connection with the solar cell through silver paste dots.

8. An EPD module as described in claim 7, characterized in that: The solar cell is provided with two conductive electrodes, and the two conductive electrodes on the solar cell are simultaneously welded to the conductive electrodes on the TFT array through silver paste points.

9. An EPD module as described in any one of claims 1-8, characterized in that: It also includes a light intensity detection component, which includes a photosensitive sensor disposed on the working surface of the TFT array in an area not covered by the FPL.

10. An EPD module as described in claim 9, characterized in that: The light intensity detection component also includes a sampling amplification circuit and an AD conversion circuit disposed on a printed circuit board. The photosensitive sensor converts ambient light into an electrical signal through photoelectric conversion, and the collected electrical signal is transmitted to the control circuit via the sampling amplification circuit and the AD conversion circuit.

11. An EPD module as described in any one of claims 1-8, characterized in that: It also includes a charge / discharge management module, which is integrated on the printed circuit board and electrically connected to the solar cell module and / or the NFC antenna, the energy storage module, the control circuit, and the display module, respectively; and The charge / discharge management method of the charge / discharge management module includes the following steps: S1, Charge / Discharge Operating Mode: Allows the energy storage components to charge and discharge, and allows the solar cells and / or the NFC antenna to directly power the load; S2. When the voltage of the energy storage component is greater than or equal to the overcharge voltage, it enters the overcharge protection mode: the energy storage component is prohibited from charging but the energy storage component is allowed to output power, and the solar cell and / or the NFC antenna are allowed to directly power the load; otherwise, it enters the charge and discharge working mode from the overcharge protection mode. S3. When the voltage of the energy storage component is less than or equal to the over-discharge voltage, the over-discharge protection mode is entered: the power output of the energy storage component is prohibited, and the solar cell component and / or the NFC antenna are allowed to charge the energy storage component using the electrical energy converted from solar energy or near-field coupling energy. Conversely, it switches from over-discharge protection mode to charge / discharge operation mode. S4. After entering the over-discharge protection mode and passing the standby buffer time, the charge and discharge management module enters the deep sleep standby state. S5. When the following conditions are met simultaneously: the power supply of the solar cell module or NFC antenna is greater than the wake-up power, and the energy storage component is not in over-discharge protection mode, the power input triggers wake-up, ending the deep sleep standby state; and S6. When the voltage of the energy storage component is greater than the minimum output voltage, it enters the charging and discharging working mode.

12. An electronic price tag, characterized in that: Includes the EPD module as described in any one of claims 1-11.

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