Electronic paper display device and control method thereof

Abstract

The application discloses an electronic paper display device and a control method thereof, which comprises an electronic paper display module, a control module, a solar energy collection module, a micro-light energy collection module, an energy storage unit, and a first charging management circuit.The solar energy collection module is electrically connected to the energy storage unit through the first charging management circuit, wherein the first charging management circuit comprises a solar power management chip and a first anti-reverse charging diode.The input end of the solar power management chip is connected to the solar energy collection module, and the output end of the solar power management chip is connected to the energy storage unit in series after the first anti-reverse charging diode.The application realizes self-adaptive safe charging of the electronic paper under indoor and outdoor variable lighting environments, and improves the endurance reliability and application range of the electronic paper device.

Description

Technical Field

[0001] This invention relates to the field of electronic paper display technology, and in particular to an electronic paper display device and its control method. Background Technology

[0002] Electronic paper display technology, especially cholesteric liquid crystal-based displays, has been widely used in electronic price tags, digital signage, and wearable devices due to its unique bistable characteristics and low power consumption. Cholesteric liquid crystals can stably maintain their planar state (P-state) without an external field. In this state, the liquid crystal molecules are arranged in a helical pattern with the helical axis perpendicular to the substrate, selectively reflecting incident light of specific wavelengths. This enables reflective displays that rely on ambient light without backlighting, forming the physical basis for its ultra-low power consumption. By applying an electric field, it can be driven to a homeotropic state (H-state), at which point the helical structure disappears and the display layer becomes transparent. Utilizing its bistable switching between the P-state and H-state (or focal conic state FC), image content can be written and retained long-term, consuming only a small amount of power during refresh.

[0003] Based on the aforementioned extremely low sustaining power consumption and the inherent characteristics of reflective displays, combining photovoltaic energy harvesting technology with cholesteric liquid crystal electronic paper to pursue energy self-sufficiency or even "perpetual power" has become a clear technological development direction in this field. Currently, there are two main technological paths to achieve this goal:

[0004] The first type of solution targets outdoor fixed applications and mainly integrates conventional solar panels. This type of solution has high charging efficiency under direct sunlight and can provide sufficient energy for the device. However, solar panels typically have high start-up voltage and power threshold. In low-to-medium illumination environments such as indoors, cloudy / rainy days, or evenings (e.g., illumination below 10,000 lux), their power generation capacity drops sharply or they may even fail to start, causing the device to experience power outages in variable environments and severely limiting its application scenarios.

[0005] The second type of solution, adapted to low-light environments such as indoors, employs specially optimized low-light (or low-energy) photovoltaic (PV) collection films and their accompanying low-voltage management chips. This type of solution can efficiently start and collect energy at illuminance levels of hundreds to thousands of lux, perfectly matching indoor lighting conditions. However, low-light collection chips are typically optimized for lower input current and voltage, and their internal components are quite sophisticated. Once the device is moved outdoors and exposed to intense light exceeding tens or even hundreds of thousands of lux, the output voltage and current generated by the low-light film will far exceed its design safety range, easily leading to overvoltage or overcurrent breakdown of the management chip. Therefore, this type of solution inherently lacks robustness for outdoor use.

[0006] In summary, existing photovoltaic power supply solutions for electronic paper suffer from a core contradiction: fragmented applicability to various scenarios and a lack of environmental adaptability. Outdoor solutions cannot utilize low indoor light, while indoor solutions cannot withstand strong outdoor light. Simply connecting two collection modules in parallel cannot solve the problem because the safety risks of the low-light module still exist. Therefore, there is an urgent need in this field for a compatible power supply system and control method that can intelligently sense ambient light intensity, automatically adapt to the energy collection mode, and ensure the safe operation of the low-light module across the entire light spectrum, in order to truly unleash the potential of cholesteric liquid crystal electronic paper in all-weather, cross-scenario applications. Summary of the Invention

[0007] To address the technical problems existing in the background art, the present invention proposes an electronic paper display device and its control method.

[0008] The present invention provides an electronic paper display device, comprising:

[0009] Electronic paper display module and control module;

[0010] Solar energy collection module, used to convert solar energy into electrical energy;

[0011] A low-light energy harvesting module is used to convert ambient low-light into electrical energy;

[0012] An energy storage unit is used to store electrical energy provided by the solar energy collection module and the micro-light energy collection module;

[0013] The solar energy collection module is electrically connected to the energy storage unit through a first charging management circuit. The first charging management circuit includes a solar power management chip and a first anti-reverse charging diode. The input terminal of the solar power management chip is connected to the solar energy collection module, and the output terminal of the solar power management chip is connected to the energy storage unit after being connected in series with the first anti-reverse charging diode.

[0014] The low-light energy harvesting module is electrically connected to the control module through a second charging management circuit, which includes at least one switching module; the low-light energy harvesting module is electrically connected to the energy storage unit through a second anti-reverse charging diode.

[0015] The control module is configured to: acquire the micro-light energy charging current value; generate and output a corresponding control signal to the switch module according to the relationship between the micro-light energy charging current value and the preset first current threshold, so as to control the on / off state of the switch module, thereby switching the charging path from the micro-light energy collection module to the energy storage unit.

[0016] Preferably, the second charging management circuit includes a first current-limiting resistor, a second current-limiting resistor, and a set of switching modules. The first current-limiting resistor is disposed between the micro-light energy film of the micro-light energy collection module and the control module. One end of the first current-limiting resistor is connected to the control module and simultaneously connected to the micro-light energy power management chip of the micro-light energy collection module and one end of the second current-limiting resistor. The other end of the second current-limiting resistor is electrically connected to the switching modules. The micro-light energy film of the micro-light energy collection module is electrically connected to the switching modules, and the control module is electrically connected to the switching modules.

[0017] Preferably, the second charging management circuit includes a first current-limiting resistor, a second current-limiting resistor, and two sets of switching modules. One end of the first current-limiting resistor is connected to the power management chip of both the control module and the micro-light energy collection module. The other end of the first current-limiting resistor is electrically connected to one of the two sets of switching modules. One end of the second current-limiting resistor is connected to both the control module and the power management chip of the micro-light energy collection module. The other end of the second current-limiting resistor is electrically connected to the other set of switching modules. The control module is electrically connected to both sets of switching modules, and the two sets of switching modules are respectively connected to the micro-light energy membrane of the micro-light energy collection module.

[0018] Preferably, the resistance of the first current-limiting resistor is 7 to 8 times the resistance of the second current-limiting resistor.

[0019] Preferably, a sampling point T1 is provided at one end of the first current-limiting resistor, and the control module obtains the micro-light energy charging current value through the sampling point T1.

[0020] Preferably, the switching module includes:

[0021] The PMOS transistor has its source electrically connected to the micro-light energy harvesting module's micro-light energy film, and its drain electrically connected to one end of the second current-limiting resistor.

[0022] The NPN transistor has its collector electrically connected to the gate of the PMOS transistor, its emitter grounded, and its base electrically connected to the control module. The control module controls the NPN transistor to turn on or off by outputting a high-level or low-level signal to the base of the NPN transistor, thereby driving the gate voltage of the PMOS transistor to change, thus realizing the on / off control of the PMOS transistor.

[0023] Preferably, the micro-light energy collection module's micro-light energy film is attached to the back of the electronic paper display module, and the solar panel of the solar energy collection module is externally placed on the electronic paper display module.

[0024] Preferably, the micro-light energy collection module's micro-light energy film and the solar panel of the solar energy collection module are both attached to the back of the electronic paper display module.

[0025] The present invention proposes a control method for an electronic paper display device, comprising the following steps:

[0026] S1. Obtain the real-time detected value of the low-light energy charging current;

[0027] S2. Compare the low-light energy charging current value with the preset first current threshold.

[0028] S3. When the micro-light energy charging current value is greater than or equal to the first current threshold, the first control signal is output to the switch module to control the switch module to disconnect.

[0029] S4. When the micro-light energy charging current value is less than the first current threshold, output the second control signal to the switch module to control the switch module to turn on.

[0030] Preferably, after step S3, the method further includes:

[0031] The micro-light energy charging current value is continuously acquired and compared with a preset second current threshold, wherein the second current threshold is less than the first current threshold;

[0032] When the micro-light energy charging current value is less than the second current threshold, the second control signal is output to the switch module to control the switch module to turn on.

[0033] This invention presents an electronic paper display device and its control method that, through intelligent detection and control, achieves adaptive energy harvesting in environments with continuously changing lighting conditions, ranging from low indoor light to strong outdoor light. While ensuring the safe operation of the low-light energy harvesting module and preventing damage from overcurrent caused by strong light, it fully integrates both solar and low-light energy sources, extending the device's continuous operating time under complex lighting conditions. This improves the environmental adaptability, battery life reliability, and ease of use of electronic paper products, while reducing maintenance requirements. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the device architecture of an electronic paper display device proposed in this invention;

[0035] Figure 2 This is a schematic diagram of the structure of Embodiment 1 of the electronic paper display device proposed in this invention;

[0036] Figure 3 This is a schematic diagram of the structure of Embodiment 2 of the electronic paper display device proposed in this invention;

[0037] Figure 4 This is a schematic diagram of the workflow of a control method for an electronic paper display device proposed in this invention. Detailed Implementation

[0038] Reference Figures 1-4The present invention provides an electronic paper display device, comprising:

[0039] Electronic paper display module and control module;

[0040] Solar energy collection module, used to convert solar energy into electrical energy;

[0041] A low-light energy harvesting module is used to convert ambient low-light into electrical energy;

[0042] An energy storage unit is used to store electrical energy provided by the solar energy collection module and the micro-light energy collection module;

[0043] The solar energy collection module is electrically connected to the energy storage unit through a first charging management circuit. The first charging management circuit includes a solar power management chip and a first anti-reverse charging diode. The input terminal of the solar power management chip is connected to the solar energy collection module, and the output terminal of the solar power management chip is connected to the energy storage unit after being connected in series with the first anti-reverse charging diode.

[0044] The low-light energy harvesting module is electrically connected to the control module through a second charging management circuit, which includes at least one switching module; the low-light energy harvesting module is electrically connected to the energy storage unit through a second anti-reverse charging diode.

[0045] The control module is configured to: acquire the micro-light energy charging current value; generate and output a corresponding control signal to the switch module based on the relationship between the micro-light energy charging current value and the preset first current threshold, so as to control the on / off state of the switch module and thereby switch the charging path from the micro-light energy collection module to the energy storage unit.

[0046] In this embodiment, the second charging management circuit includes a first current-limiting resistor, a second current-limiting resistor, and a set of switching modules. The first current-limiting resistor is disposed between the micro-light energy film of the micro-light energy collection module and the control module. One end of the first current-limiting resistor is connected to the control module and simultaneously connected to the micro-light energy power management chip of the micro-light energy collection module and one end of the second current-limiting resistor. The other end of the second current-limiting resistor is electrically connected to the switching modules. The micro-light energy film of the micro-light energy collection module is electrically connected to the switching modules, and the control module is electrically connected to the switching modules.

[0047] In this embodiment, the second charging management circuit includes a first current-limiting resistor, a second current-limiting resistor, and two sets of switching modules. One end of the first current-limiting resistor is connected to the micro-light energy power management chip of both the control module and the micro-light energy collection module. The other end of the first current-limiting resistor is electrically connected to one of the two sets of switching modules. One end of the second current-limiting resistor is connected to both the control module and the micro-light energy power management chip of both the control module and the micro-light energy collection module. The other end of the second current-limiting resistor is electrically connected to the other set of switching modules. The control module is electrically connected to both sets of switching modules, and the two sets of switching modules are respectively connected to the micro-light energy membrane of the micro-light energy collection module.

[0048] In this embodiment, the resistance value of the first current-limiting resistor is 7 to 8 times that of the second current-limiting resistor.

[0049] In this embodiment, a sampling point T1 is provided at one end of the first current-limiting resistor, and the control module obtains the micro-light energy charging current value through the sampling point T1.

[0050] In this embodiment, the switch module includes:

[0051] The PMOS transistor has its source electrically connected to the micro-light energy harvesting module's micro-light energy film, and its drain electrically connected to one end of the second current-limiting resistor.

[0052] The NPN transistor has its collector electrically connected to the gate of the PMOS transistor, its emitter grounded, and its base electrically connected to the control module. The control module controls the NPN transistor to turn on or off by outputting a high-level or low-level signal to the base of the NPN transistor, thereby driving the gate voltage of the PMOS transistor to change, thus realizing the on / off control of the PMOS transistor.

[0053] In this embodiment, the low-light energy collection module's low-light energy film is attached to the back of the electronic paper display module, and the solar panel of the solar energy collection module is externally mounted on the electronic paper display module. Both the low-light energy collection module's low-light energy film and the solar panel of the solar energy collection module are attached to the back of the electronic paper display module.

[0054] In one embodiment, a low-light film is attached to the back of the electronic paper display module, while the solar panel is externally mounted outside the electronic paper display module and the entire display device housing via a bracket or other means to obtain optimal sunlight exposure. In another embodiment, both the solar panel and the low-light film are attached to the back of the electronic paper display module, and they can be arranged side by side, each occupying approximately half the area.

[0055] Example 1:

[0056] In this embodiment, as Figure 2As shown, the control module is implemented using a single-chip microcomputer (MCU). The solar energy collection module consists of a solar panel and a solar power management chip with maximum power point tracking (MPPT) functionality. The low-light energy collection module consists of a low-light energy film and a low-light energy power management chip. The energy storage unit uses a supercapacitor. The first charging management circuit consists of a solar power management chip and a first reverse-charge protection diode D2 connected in series. The solar panel is connected to the input terminal, and the output terminal is connected to the positive terminal of the supercapacitor via D2. The electronic paper display module serves as the information display interface.

[0057] The second charging management circuit specifically includes:

[0058] The switching module consists of a PMOS transistor Q1 and an NPN transistor Q2. The gate (G) of the PMOS transistor Q1 is electrically connected to the collector of the NPN transistor Q2, the base of the NPN transistor Q2 is electrically connected to the control module, the emitter of the NPN transistor Q2 is grounded, the source (S) of the PMOS transistor Q1 is electrically connected to the other end of the first current-limiting resistor R1 and the micro-light energy film, and the drain (D) of the PMOS transistor Q1 is electrically connected to the other end of the second current-limiting resistor R2.

[0059] First current-limiting resistor R1: One end of the first current-limiting resistor R1 is the sampling point T1, and preferably, the resistance value is 100Ω.

[0060] Preferably, the second current-limiting resistor R2 has a resistance of 14Ω. The resistance of the first current-limiting resistor R1 is approximately 7.14 times that of the second current-limiting resistor R2.

[0061] The second anti-reverse charging diode D1 has its anode connected to the micro-light power management chip and its cathode connected to the positive terminal of the supercapacitor.

[0062] In this embodiment, a low-light film is attached to the back of the electronic paper display module, and the solar panel is externally mounted on the display module via a bracket.

[0063] The specific parameter settings for the control module (MCU) are as follows:

[0064] Acquisition of micro-light energy charging current value: The MCU periodically samples the real-time micro-light energy charging current value Imicro at sampling point T1 through its internal analog-to-digital converter (ADC).

[0065] The first current threshold is set to 100mA; the second current threshold is set to less than 100mA, which implements hysteresis comparison and prevents frequent state switching.

[0066] Taking the change in ambient light on a sunny day as an example, the working process is explained as follows:

[0067] Normal dual-mode charging phase (corresponding to Imicro < 100mA):

[0068] In the morning (e.g., 7:00-11:00), after the light intensity decreases in the afternoon, and at night, the ambient illuminance is typically below 50,000 lux. At these times, the output voltage of the micro-light-emitting film is low, and the micro-light-emitting charging current value Imicro detected by sampling point T1 is less than 100mA. Upon detecting this condition, the MCU controls the GPIO port to output a low level (0V), causing the NPN transistor Q2 to turn off, which in turn turns on the PMOS transistor Q1.

[0069] The micro-light energy charging path is as follows: from the micro-light energy film to the parallel connection of the first current-limiting resistor R1 and the second current-limiting resistor R2, and then through the micro-light energy power management chip and the second anti-reverse charging diode D1 to the supercapacitor; wherein R2 can be controlled by Q1 to switch on and off.

[0070] Solar charging path: Solar power management chip output → First anti-reverse charging diode D2 → Supercapacitor.

[0071] At this time, the two energy sources charge the supercapacitor simultaneously, and the system is in a state of high-efficiency charging.

[0072] Current limiting protection phase (corresponding to Imicro≥100mA):

[0073] At midday (e.g., between 11:00 AM and 2:00 PM), ambient illuminance can reach 50,000 lux to 130,000 lux. The output voltage of the micro-light-emitting film increases significantly. If left uncontrolled, Imicro will exceed 100mA, potentially damaging the micro-light-emitting power management chip. The MCU continuously monitors Imicro through sampling point T1. When it detects that Imicro reaches or exceeds 100mA, it immediately switches the control GPIO port output to a high level (3.3V). This turns on the NPN transistor Q2, thereby pulling the gate G of the PMOS transistor Q1 low to ground potential, and Q1 quickly turns off.

[0074] Low-light energy path change: After Q1 is turned off, the main charging circuit is cut off. The low-light current is forced to flow through the protection path: low-light power management chip output → first current-limiting resistor R1 → VCC power supply terminal of the low-light power management chip. Since the resistance of R1 (100Ω) is much larger than that of R2 (14Ω), and it forms a loop with the power supply input terminal of the low-light power management chip, the current is strictly limited to a safe range. For example, even if the diaphragm output voltage rises to 8V under the highest illuminance, considering the VCC operating voltage of the low-light power management chip and the loop voltage drop, the current flowing through R1 will be limited to less than about 50mA, ensuring the safety of the low-light power management chip.

[0075] Solar path: Unaffected, continues to charge the supercapacitor via D2, with solar energy becoming the primary charging source.

[0076] Status recovery phase:

[0077] As afternoon light intensity begins to decrease (e.g., after 2 PM), ambient illuminance drops from its peak, and Imicro decreases accordingly. The MCU continuously monitors this. When Imicro is detected to fall below the second current threshold (determined by the voltage value corresponding to sampling point T1), the MCU will control the GPIO port output to return to a low level (0V). This will cause NPN transistor Q2 to turn off again, and PMOS transistor Q1 to turn on again, switching the system from the "current limiting protection stage" back to the "normal dual-mode charging stage".

[0078] Example 2:

[0079] like Figure 3 As shown, Embodiment 2 provides an optimized circuit scheme based on Embodiment 1. In this embodiment, the first current-limiting resistor R1 of the second charging management circuit is selected to have a resistance of 50Ω, and the second current-limiting resistor R2 is selected to have a resistance of 12Ω. The resistance of R1 is approximately 4.2 times that of R2. This ratio, after optimization, can enable the system to achieve a higher level of safe charging current for low-light energy under strong light.

[0080] In this embodiment, the second charging management circuit includes two sets of switching modules, namely as follows: Figure 3 The diagram shows switch module one and switch module two. Switch module one consists of a PMOS transistor Q5 and an NPN transistor Q6. The source of Q5 is electrically connected to the micro-light energy harvesting membrane of the micro-light energy harvesting module, the drain of Q5 is electrically connected to the other end of the second current-limiting resistor R2, the gate of Q5 is electrically connected to the collector of Q6, the emitter of Q6 is grounded, and the base of Q6 is electrically connected to the control module. Switch module two consists of a PMOS transistor Q3 and an NPN transistor Q4. The source of Q3 is electrically connected to the micro-light energy harvesting membrane of the micro-light energy harvesting module. The drain of Q3 is electrically connected to the other end of the first current-limiting resistor R1, the gate of Q3 is electrically connected to the collector of Q4, the emitter of Q4 is grounded, and the base of Q4 is electrically connected to the control module. The control module independently outputs high-level or low-level control signals to the bases of Q6 and Q4 to independently control the on / off state of switch module one and switch module two. Thus, under strong light conditions, different current-limiting paths are selected according to the magnitude of the micro-light energy charging current, ensuring the safe operation of the micro-light energy power management chip while optimizing energy harvesting efficiency.

[0081] The operating logic and threshold setting of the control module (MCU) are similar to those in Embodiment 1. It continuously samples the micro-light energy charging current of sampling point T1 and makes judgments and switches based on the preset first current threshold (e.g., 100mA) and second current threshold.

[0082] During operation, the MCU continuously monitors the micro-solar energy charging current at sampling point T1. When the current value is below 100mA, the MCU controls both switch module one and switch module two to conduct. At this time, the micro-solar energy simultaneously charges the energy storage unit through two charging paths: Path one is the output of the micro-solar energy power management chip → the second current-limiting resistor R2 → the conducting switch module one → the second anti-reverse charging diode D1 → the supercapacitor; Path two is the output of the micro-solar energy power management chip → the first current-limiting resistor R1 → the conducting switch module two → the second anti-reverse charging diode D1 → the supercapacitor. The system is in a highly efficient state of simultaneous charging by micro-solar energy and solar energy.

[0083] When the sunlight is strongest at midday and the low-light charging current reaches or exceeds 100mA, the MCU immediately controls switch module one to turn off and switch module two to remain on. This ensures that the low-light current flows only through the high-resistance charging path formed by the first current-limiting resistor R1 (i.e., path two mentioned above), thereby safely limiting the charging current to an upper limit of approximately 100mA. Because the resistance of R2 is significantly reduced in this embodiment, this current-limiting strategy can maintain continuous charging of the energy storage unit even under extremely strong sunlight, improving the energy harvesting capability under strong light conditions compared to Embodiment 1, while solar charging continues unaffected.

[0084] When the afternoon light intensity decreases and the micro-light energy charging current drops below the second current threshold, the MCU controls switch module one to turn on again, and the system resumes dual-mode charging (both switch modules one and two are on). At night or in the absence of light, the system maintains both switch modules one and two on, relying solely on the micro-light energy module to collect a small amount of ambient light.

[0085] Reference Figures 1-4 The present invention proposes a control method for an electronic paper display device, comprising the following steps:

[0086] S1. Obtain the real-time detected value of the low-light energy charging current;

[0087] S2. Compare the low-light energy charging current value with the preset first current threshold.

[0088] S3. When the micro-light energy charging current value is greater than or equal to the first current threshold, the first control signal is output to the switch module to control the switch module to disconnect.

[0089] S4. When the micro-light energy charging current value is less than the first current threshold, output the second control signal to the switch module to control the switch module to turn on.

[0090] In this embodiment, after step S3, the following steps are also included:

[0091] The micro-light energy charging current value is continuously acquired and compared with a preset second current threshold, wherein the second current threshold is less than the first current threshold;

[0092] When the micro-light energy charging current value is less than the second current threshold, the second control signal is output to the switch module to control the switch module to turn on.

[0093] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An electronic paper display device, characterized in that, include: Electronic paper display module and control module; Solar energy collection module, used to convert solar energy into electrical energy; A low-light energy harvesting module is used to convert ambient low-light into electrical energy; An energy storage unit is used to store electrical energy provided by the solar energy collection module and the micro-light energy collection module; The solar energy collection module is electrically connected to the energy storage unit through a first charging management circuit. The first charging management circuit includes a solar power management chip and a first anti-reverse charging diode. The input terminal of the solar power management chip is connected to the solar energy collection module, and the output terminal of the solar power management chip is connected to the energy storage unit after being connected in series with the first anti-reverse charging diode. The low-light energy harvesting module is electrically connected to the control module through a second charging management circuit, which includes at least one switching module; the low-light energy harvesting module is electrically connected to the energy storage unit through a second anti-reverse charging diode. The control module is configured to: acquire the micro-light energy charging current value; generate and output a corresponding control signal to the switch module according to the relationship between the micro-light energy charging current value and the preset first current threshold, so as to control the on / off state of the switch module, thereby switching the charging path from the micro-light energy collection module to the energy storage unit. The second charging management circuit includes a first current-limiting resistor, a second current-limiting resistor, and a set of switching modules. The first current-limiting resistor is disposed between the micro-light energy film of the micro-light energy collection module and the control module. One end of the first current-limiting resistor is connected to the control module and simultaneously connected to the micro-light energy power management chip of the micro-light energy collection module and one end of the second current-limiting resistor. The other end of the second current-limiting resistor is electrically connected to the switching modules. The micro-light energy film of the micro-light energy collection module is electrically connected to the switching modules, and the control module is electrically connected to the switching modules. Alternatively, the second charging management circuit includes a first current-limiting resistor, a second current-limiting resistor, and two sets of switching modules. One end of the first current-limiting resistor is connected to the power management chip of both the control module and the micro-light energy collection module. The other end of the first current-limiting resistor is electrically connected to one set of the two sets of switching modules. One end of the second current-limiting resistor is connected to both the control module and the power management chip of the micro-light energy collection module. The other end of the second current-limiting resistor is electrically connected to the other set of the two sets of switching modules. The control module is electrically connected to both sets of switching modules. The two sets of switching modules are connected to the micro-light energy membrane of the micro-light energy collection module. A sampling point T1 is provided at one end of the first current-limiting resistor, and the control module obtains the micro-light energy charging current value through the sampling point T1; The switching module includes: The source of the PMOS transistor is electrically connected to the micro-light energy film of the micro-light energy collection module. When the second charging management circuit includes a set of switching modules, the drain of the PMOS transistor is electrically connected to one end of the second current limiting resistor. When the second charging management circuit includes two sets of switching modules, the drain of the PMOS transistor is electrically connected to one end of the first current limiting resistor or one end of the second current limiting resistor. The NPN transistor has its collector electrically connected to the gate of the PMOS transistor, its emitter grounded, and its base electrically connected to the control module. The control module controls the NPN transistor to turn on or off by outputting a high-level or low-level signal to the base of the NPN transistor, thereby driving the gate voltage of the PMOS transistor to change, so as to realize the on / off control of the PMOS transistor. When the switching module is off, the current is forced to flow only through the high-resistance first current-limiting resistor to form a protection circuit; when the switching module is on, the current preferentially flows through the low-resistance second current-limiting resistor to form a charging circuit.

2. The electronic paper display device according to claim 1, characterized in that, The resistance of the first current-limiting resistor is 7 to 8 times that of the second current-limiting resistor.

3. The electronic paper display device according to claim 1, characterized in that, The micro-light energy collection module's micro-light energy film is attached to the back of the electronic paper display module, while the solar energy collection module's solar panel is externally mounted on the electronic paper display module.

4. The electronic paper display device according to claim 1, characterized in that, The micro-light energy collection module's micro-light energy film and the solar energy collection module's solar panel are both attached to the back of the electronic paper display module.

5. A control method for an electronic paper display device, characterized in that, Applied to the electronic paper display device as described in any one of claims 1-4, the method comprises the following steps: S1. Obtain the real-time detected value of the low-light energy charging current; S2. Compare the low-light energy charging current value with the preset first current threshold. S3. When the micro-light energy charging current value is greater than or equal to the first current threshold, the first control signal is output to the switch module to control the switch module to disconnect. S4. When the micro-light energy charging current value is less than the first current threshold, output the second control signal to the switch module to control the switch module to turn on.

6. The control method for the electronic paper display device according to claim 5, characterized in that, Following step S3, the following is also included: The micro-light energy charging current value is continuously acquired and compared with a preset second current threshold, wherein the second current threshold is less than the first current threshold; When the micro-light energy charging current value is less than the second current threshold, the second control signal is output to the switch module to control the switch module to turn on.

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