Electronic paper display device and charging optimization method thereof

Abstract

The application discloses an electronic paper display device and a charging optimization method thereof. The electronic paper display device comprises an electronic paper display panel, a solar film, a sampling circuit, a comparison and judgment circuit and a control circuit. The solar film is arranged on the non-display side of the electronic paper display panel and is used for receiving light transmitted through the electronic paper display panel and converting the light into electric energy. The sampling circuit collects real-time output electric parameters of the solar film. The comparison and judgment circuit compares the real-time output electric parameters with reference electric parameter values, and outputs a trigger signal when the real-time output electric parameters are lower than the reference electric parameter values. The control circuit outputs a picture adjustment driving signal to a data driving interface of the electronic paper display panel in response to receiving the trigger signal, so as to drive the electronic paper display panel to increase the display quantity of black pixels in the current display picture. The electronic paper display device and the charging optimization method thereof can improve the charging efficiency of the electronic paper display device in a dim light environment and prolong the endurance time.

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 charging optimization method. Background Technology

[0002] Electronic paper display technology is widely used in e-readers, electronic tags, and other fields due to its paper-like display effect and low power consumption. To further extend battery life, existing technologies have proposed a solution of placing a solar film on the backlight side of the electronic paper display panel, using the light energy transmitted through the panel to power or replenish the device's power.

[0003] like Figure 1 As shown, when the pixels of the electronic paper display panel are in a black state, the liquid crystal layer is transparent, allowing light to pass through the panel and reach the solar film. When the pixels are in a white state, the liquid crystal layer is reflective, and most of the light is reflected, failing to effectively reach the solar film. Therefore, the charging efficiency of the solar film is positively correlated with the number of black pixels in the displayed image.

[0004] However, existing technologies have the following shortcomings: Firstly, e-paper displays typically feature white backgrounds with black text, and the proportion of white pixels is much higher than that of black pixels. This results in the actual light-receiving area of ​​the solar film being much smaller than its total area, thus failing to fully utilize the charging efficiency.

[0005] Secondly, in low-light environments such as cloudy days or indoors, the light itself is weak. If the displayed image is still mainly white, the solar film will receive even less light energy, and the generated power will not even be enough to compensate for the device's own power consumption, which will seriously affect the battery life.

[0006] Third, although there are existing solutions that adjust display parameters based on ambient light conditions to reduce power consumption, the adjustment is based on ambient light brightness rather than the actual charging efficiency of the solar film. When the light is the same but the black-and-white ratio of the screen is different, the charging efficiency varies significantly, so it is impossible to accurately determine the true charging status of the solar film.

[0007] In conclusion, how to effectively improve the charging efficiency of solar films in low-light environments is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0008] To address the technical problems existing in the background art, the present invention proposes an electronic paper display device and its charging optimization method.

[0009] The present invention provides an electronic paper display device, comprising: An electronic paper display panel has a display side and a non-display side that are arranged opposite to each other, with the non-display side being the backlight side; A solar film is installed on the non-display side of the electronic paper display panel. The solar film is used to receive light passing through the electronic paper display panel and convert light energy into electrical energy. The sampling circuit is electrically connected to the power output terminal of the solar film and is configured to collect the real-time output electrical parameters of the solar film. The comparison and judgment circuit is electrically connected to the signal output terminal of the sampling circuit. The comparison and judgment circuit is configured to receive the real-time output electrical parameters and compare the real-time output electrical parameters with the reference electrical parameter value. When the real-time output electrical parameters are lower than the reference electrical parameter value, the comparison and judgment circuit outputs a trigger signal. The control circuit has its signal input terminal electrically connected to the signal output terminal of the comparison and judgment circuit, and its drive signal output terminal electrically connected to the data drive interface of the electronic paper display panel. The control circuit is configured to output a screen adjustment drive signal to the data drive interface in response to receiving a trigger signal. The screen adjustment drive signal is used to drive the electronic paper display panel to increase the number of black pixels displayed in the current display screen.

[0010] Preferably, the sampling circuit includes: The sampling resistor is connected in series in the power output circuit of the solar film; The differential amplifier has its two input terminals connected to the two ends of the sampling resistor, and its output terminal serves as the signal output terminal of the sampling circuit. The differential amplifier is used to output a voltage sampling signal that characterizes the real-time output current of the solar film.

[0011] Preferably, the control circuit includes: The memory stores the pixel adjustment program. The processor is coupled to the memory and reads the pixel adjustment program. The processor's first input port is used as a signal input terminal, and the processor's data output port is used as a drive signal output terminal. When the processor executes the pixel adjustment program, it reads the original pixel dataset corresponding to the current display frame by frame. The original pixel dataset contains the original grayscale value of each pixel. The processor determines at least a portion of the non-black pixels from the original pixel dataset as pixels to be adjusted according to a preset selection strategy; The processor replaces the original grayscale value of the pixel to be adjusted with the target grayscale value corresponding to the black display state to generate the adjusted pixel dataset; The processor adjusts the drive signals based on the adjusted pixel dataset to generate the image.

[0012] Preferably, the preset selection strategy is as follows: The processor determines the selection priority based on the original grayscale values ​​of each pixel from low to high, and prioritizes the non-black pixels with the lowest original grayscale values ​​as the pixels to be adjusted.

[0013] Preferably, the preset selection strategy is as follows: The processor divides the current display screen into several pixel blocks, calculates the average value of the original grayscale values ​​of the pixels contained in each pixel block, and identifies all non-black pixels in the pixel block with the lowest average value as pixels to be adjusted.

[0014] Preferably, after the output screen adjustment drive signal is received, the control circuit continuously receives the real-time output electrical parameters fed back by the sampling circuit; when the real-time output electrical parameters recover to a value higher than the second reference electrical parameter value and the duration exceeds a predetermined time, the control circuit outputs a screen recovery drive signal to the data drive interface. The screen recovery drive signal is used to drive the electronic paper display panel to restore the current display screen to the display state before adjustment, or to gradually restore the black pixels to their respective original grayscale values ​​in multiple frames.

[0015] Preferably, the electronic paper display panel adopts a grayscale display driving architecture, which achieves different grayscale levels by configuring different numbers of black pixels in a pixel array composed of n×n pixels, where n is a positive integer greater than or equal to 2; the control circuit increases the number of black pixels displayed by reducing the display grayscale level of the current display screen.

[0016] Preferably, the comparison and judgment circuit includes: A reference voltage source is used to generate a reference voltage signal that corresponds to the reference electrical parameter value. The voltage comparator has its first input terminal electrically connected to the signal output terminal of the sampling circuit, its second input terminal electrically connected to the output terminal of the reference voltage source, and its output terminal serving as the signal output terminal of the comparison and judgment circuit.

[0017] This invention proposes a charging optimization method for an electronic paper display device. The electronic paper display device includes an electronic paper display panel, a solar film, and a control circuit. The control circuit drives the electronic paper display panel. The method is executed by the control circuit and includes the following steps: Collect real-time output electrical parameters of the solar film; Compare the real-time output electrical parameters with the reference electrical parameter values; When the real-time output electrical parameters are lower than the reference electrical parameter values, a screen adjustment drive signal is generated. The screen adjustment drive signal is output to the data drive interface of the electronic paper display panel to drive the electronic paper display panel to increase the number of black pixels displayed in the current screen.

[0018] Preferably, the step of adjusting the driving signal for generating the image is executed by the control circuit, specifically including: Obtain the original pixel dataset corresponding to the currently displayed screen, wherein the original pixel dataset contains the original grayscale value of each pixel; The selection priority is determined based on the original grayscale values ​​of each pixel from low to high, and at least a portion of the non-black pixels with the lowest original grayscale values ​​are selected as the pixels to be adjusted. The original grayscale values ​​of the pixels to be adjusted are replaced with the target grayscale values ​​corresponding to the black display state to generate the adjusted pixel dataset; The drive signal is adjusted based on the image generated from the adjusted pixel dataset.

[0019] In this invention, the proposed electronic paper display device and its charging optimization method acquire real-time output electrical parameters of the solar film through a sampling circuit, and use these real-time output electrical parameters as a direct basis for judging whether the charging efficiency is insufficient. Compared with the open-loop control method of the prior art that only infers the illumination conditions through an ambient light sensor, this application directly reflects the actual power generation capacity of the solar film, avoiding the judgment deviation caused by the interference of the electronic paper display screen status on the charging efficiency, and realizing accurate perception of charging efficiency. When insufficient charging efficiency is detected, this application actively outputs an adjustment drive signal to the electronic paper display panel through a control circuit. By increasing the number of black pixels in the current display, and utilizing the physical characteristics of electronic paper display panels—black state transmits light and white state reflects light—the light-receiving area of ​​the solar film is directly increased. This allows more light energy to reach the solar film and be converted into electrical energy, thereby improving the actual charging efficiency of the solar film in low-light environments such as cloudy days, indoors, or early morning and evening. Simultaneously, this application continuously monitors the real-time output electrical parameters of the solar film and automatically controls the display to return to normal after the charging efficiency recovers. This forms a closed-loop control mechanism of detection-judgment-adjustment-recovery, achieving dynamic optimization of charging efficiency and maximizing the user's visual experience. Attached Figure Description

[0020] Figure 1 This is a schematic diagram showing the relative positions of existing electronic paper and solar film. Figure 2 This is a schematic diagram of the device architecture of an electronic paper display device proposed in this invention; Figure 3 This is a schematic diagram of grayscale distribution for one embodiment of an existing electronic paper display device. Figure 4 This is a schematic diagram of grayscale distribution of one embodiment of an electronic paper display device proposed in this invention. Figure 5This is a flowchart illustrating the charging optimization method for an electronic paper display device proposed in this invention. Detailed Implementation

[0021] Reference Figures 2-4 The present invention provides an electronic paper display device, comprising: An electronic paper display panel has a display side and a non-display side that are arranged opposite to each other, with the non-display side being the backlight side.

[0022] It should be noted that, in this embodiment, the electronic paper display panel preferably adopts cholesteric liquid crystal display technology.

[0023] A solar film is installed on the non-display side of an electronic paper display panel. The solar film is used to receive light passing through the electronic paper display panel and convert light energy into electrical energy.

[0024] It's important to note that when a pixel in an e-paper display panel is in a black state, the corresponding liquid crystal layer is essentially transparent, allowing external light to pass through and reach the solar film. Conversely, when a pixel is in a white state, the corresponding liquid crystal layer is reflective, reflecting most of the incident light back, preventing it from effectively reaching the solar film. Therefore, the more black pixels an e-paper display panel displays, the more light energy the solar film receives, resulting in higher charging efficiency.

[0025] The sampling circuit is electrically connected to the power output terminal of the solar film and is configured to collect the real-time output electrical parameters of the solar film.

[0026] In this embodiment, the sampling circuit includes: The sampling resistor is connected in series in the power output circuit of the solar film; The differential amplifier has its two input terminals connected to the two ends of the sampling resistor, and its output terminal serves as the signal output terminal of the sampling circuit. The differential amplifier is used to output a voltage sampling signal that characterizes the real-time output current of the solar film.

[0027] Specifically, the real-time output electrical parameter can be any one or a combination of the real-time output voltage, real-time output current, or real-time output power of the solar film, as long as it can characterize the current charging efficiency of the solar film. In this embodiment, the real-time output electrical parameter is preferably the real-time output power.

[0028] The comparison and judgment circuit is electrically connected to the signal output terminal of the sampling circuit. The comparison and judgment circuit is configured to receive the real-time output electrical parameters and compare the real-time output electrical parameters with the reference electrical parameter value. When the real-time output electrical parameters are lower than the reference electrical parameter value, the comparison and judgment circuit outputs a trigger signal.

[0029] In this embodiment, the comparison and judgment circuit includes: A reference voltage source is used to generate a reference voltage signal that corresponds to the reference electrical parameter value. The voltage comparator has its first input terminal electrically connected to the signal output terminal of the sampling circuit, its second input terminal electrically connected to the output terminal of the reference voltage source, and its output terminal serving as the signal output terminal of the comparison and judgment circuit.

[0030] Specifically, the reference electrical parameter value can be a fixed value pre-stored in the electronic paper display device, or a value dynamically adjusted according to the current operating state of the electronic paper display device. Preferably, the reference electrical parameter value is 40% to 60% of the average output power of the solar film of the electronic paper display device under normal display conditions, more preferably 50%.

[0031] The control circuit has its signal input terminal electrically connected to the signal output terminal of the comparison and judgment circuit, and its drive signal output terminal electrically connected to the data drive interface of the electronic paper display panel.

[0032] In this embodiment, the control circuit includes: The memory stores the pixel adjustment program. The processor is coupled to the memory and reads the pixel adjustment program. The processor's first input port is used as a signal input terminal, and the processor's data output port is used as a drive signal output terminal. When the processor executes the pixel adjustment program, it reads the original pixel dataset corresponding to the current display frame by frame. The original pixel dataset contains the original grayscale value of each pixel. The processor determines at least a portion of the non-black pixels from the original pixel dataset as pixels to be adjusted according to a preset selection strategy; The processor replaces the original grayscale value of the pixel to be adjusted with the target grayscale value corresponding to the black display state to generate the adjusted pixel dataset; The processor adjusts the drive signals based on the adjusted pixel dataset to generate the image.

[0033] Specifically, the processor can be any one of a microcontroller (MCU), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), or a field-programmable gate array (FPGA). In this embodiment, the processor is preferably a low-power microcontroller, such as an ARM Cortex-M series MCU.

[0034] When the processor executes the pixel adjustment program, it performs the following operations: First, the processor reads the raw pixel dataset corresponding to the currently displayed image frame by frame. This raw pixel dataset contains the raw grayscale values ​​of each pixel in the currently displayed image. For 8-bit grayscale display, the grayscale value ranges from 0 to 255, where a grayscale value of 0 corresponds to pure black and a grayscale value of 255 corresponds to pure white. For binary black and white display, the pixel state can be directly represented as black or white.

[0035] Next, the processor determines at least a portion of the non-black pixels from the original pixel dataset as pixels to be adjusted, according to a preset selection strategy.

[0036] The processor then replaces the original grayscale value of the pixel to be adjusted with the target grayscale value corresponding to the black display state. For 8-bit grayscale display, the target grayscale value is 0; for binary black and white display, the target grayscale value is the data value corresponding to the black state. Through this replacement operation, the processor generates the adjusted pixel dataset.

[0037] Finally, the processor generates an image adjustment drive signal based on the adjusted pixel dataset. This image adjustment drive signal conforms to the communication protocol of the data drive interface of the electronic paper display panel and can drive the electronic paper display panel to display the adjusted image.

[0038] Example 1 of a preset selection strategy: Specifically, the preset selection strategy is as follows: the processor determines the selection priority based on the original grayscale value of each pixel from low to high, and prioritizes the non-black pixel with the lowest original grayscale value as the pixel to be adjusted.

[0039] The lower the original grayscale value, meaning the closer the pixel color is to black, the higher the selection priority. The processor prioritizes non-black pixels with the lowest original grayscale value as the pixels to be adjusted.

[0040] For example, suppose the pixel grayscale value distribution in a certain area of ​​the current display screen is as follows: pixel A has a grayscale value of 50 (dark gray), pixel B has a grayscale value of 120 (medium gray), and pixel C has a grayscale value of 200 (light gray). The processor, following the order of grayscale values ​​from lowest to highest, first selects pixel A with a grayscale value of 50 as the pixel to be adjusted and replaces its grayscale value with 0 (black). If more black pixels are needed, pixel B with a grayscale value of 120 is selected, and so on, until the target number of black pixels is reached.

[0041] Before performing adjustments, the processor can calculate the target increase in black pixels based on the difference between the current real-time output electrical parameters and the reference electrical parameter values. The larger the difference, the more severe the charging inefficiency, and the more black pixels need to be added. Specifically, the processor can use a preset mapping table or a linear function to map the difference to the target increase in black pixels.

[0042] After the processor completes the selection and data replacement of the pixels to be adjusted according to the above priority strategy, it generates the adjusted pixel dataset and generates the screen adjustment drive signal based on the adjusted pixel dataset.

[0043] Example 2 of the preset selection strategy: The preset selection strategy is as follows: the processor divides the current display screen into several pixel blocks, calculates the average value of the original grayscale values ​​of the pixels contained in each pixel block, and determines all non-black pixels in the pixel block with the lowest average value as pixels to be adjusted.

[0044] The size of each pixel block can be set according to actual needs, for example, each pixel block contains 2×2 pixels, 3×3 pixels, or 4×4 pixels. Preferably, each pixel block contains 3×3 pixels, for a total of 9 pixels, which corresponds to the pixel array size in the grayscale display algorithm.

[0045] The processor calculates the average value of the original grayscale values ​​of the pixels contained in each pixel block. This average value reflects the overall brightness of the pixel block. The lower the average value, the darker the pixel block is, that is, the higher the proportion of black pixels or the lower the pixel grayscale.

[0046] The processor identifies all non-black pixels in the pixel block with the lowest average value as pixels to be adjusted, and replaces all of their grayscale values ​​with the target grayscale value corresponding to the black display state.

[0047] For example, suppose the display screen is divided into several 3×3 pixel blocks. Pixel block A has an average grayscale value of 60, pixel block B has an average grayscale value of 150, and pixel block C has an average grayscale value of 210. The processor selects pixel block A with the lowest average value and replaces the grayscale values ​​of all non-black pixels in that pixel block with 0, making the entire pixel block completely black.

[0048] After the processor completes the selection and data replacement of the pixels to be adjusted according to the above pixel block adjustment strategy, it generates the adjusted pixel dataset and generates the screen adjustment drive signal based on the adjusted pixel dataset.

[0049] It should be noted that the electronic paper display panel adopts a grayscale display driving architecture. The grayscale display driving architecture achieves different grayscale levels by configuring different numbers of black pixels in a pixel array composed of n×n pixels, where n is a positive integer greater than or equal to 2. The control circuit increases the number of black pixels displayed by reducing the display grayscale level of the current display screen.

[0050] In this embodiment, as Figure 3As shown, a 3×3 pixel array (i.e., 9 pixels) is used to achieve 10 grayscale levels (grayscale 1 to grayscale 10). Specifically, grayscale 1 corresponds to 9 pixels that are completely black (100% black pixels), grayscale 10 corresponds to 9 pixels that are completely white (0% black pixels), and intermediate grayscale levels are simulated by varying numbers of black pixels. When viewed from a distance, due to the limitations of spatial resolution, the human eye perceives the mixture of light and dark in these 9 pixels as a continuous grayscale.

[0051] Based on the aforementioned grayscale display driving architecture, the control circuit increases the number of black pixels displayed by reducing the grayscale level of the current display screen. For example... Figure 4 As shown, at this time, gray levels 1 and 2 correspond to 9 pixels that are completely black (black pixels account for 100%), gray level 10 corresponds to 8 pixels that are completely white, and the intermediate gray levels each have 1 more black pixel than the original image data.

[0052] The degree of grayscale reduction can be determined based on the extent of the current charging efficiency; the lower the charging efficiency, the greater the reduction in grayscale level. The control circuit can reduce the grayscale level frame by frame or region by region, making the overall grayscale of the displayed image darker, thereby increasing the total number of black pixels.

[0053] This embodiment utilizes the underlying mechanism of the electronic paper grayscale display algorithm, namely, the one-to-one correspondence between grayscale levels and the number of black pixels. By reducing the overall grayscale levels, a significant increase in the number of black pixels can be achieved with minimal modifications. This is particularly suitable for applications such as e-readers that primarily display text and have gradual grayscale changes. It can be seen that the adjusted image shows a significant increase in black pixels, corresponding to a larger light-receiving area for the solar film and improved charging efficiency.

[0054] Once the control circuit completes the grayscale reduction, it generates an adjusted pixel dataset and outputs the image adjustment drive signal to the data drive interface based on the adjusted pixel dataset.

[0055] The control circuit is configured to output a screen adjustment drive signal to the data drive interface in response to receiving a trigger signal. The screen adjustment drive signal is used to drive the electronic paper display panel to increase the number of black pixels displayed in the current display screen.

[0056] In this embodiment, after the output screen adjustment drive signal is received, the control circuit continuously receives the real-time output electrical parameters fed back by the sampling circuit. When the real-time output electrical parameters recover to a value higher than the second reference electrical parameter value and the duration exceeds a predetermined time, the control circuit outputs a screen recovery drive signal to the data drive interface. The screen recovery drive signal is used to drive the electronic paper display panel to restore the current display screen to the display state before adjustment, or to gradually restore the black pixels to their respective original grayscale values ​​in multiple frames.

[0057] Specifically, the recovery operation can be performed in one of the following two ways: Method 1: Direct restoration; The control circuit directly switches the display screen back to its original state before adjustment; Method 2: Gradual Restoration; The control circuit gradually restores black pixels to their original grayscale values ​​over multiple frames. For example, suppose 100 pixels are adjusted from gray to black during the adjustment phase. During the restoration phase, the control circuit can gradually restore the original grayscale values ​​of 10 pixels per frame over 10 frames. The control circuit can select either of the two recovery methods mentioned above according to actual needs.

[0058] Reference Figure 5 This invention proposes a charging optimization method for an electronic paper display device. The electronic paper display device includes an electronic paper display panel, a solar film, and a control circuit. The control circuit drives the electronic paper display panel. The method is executed by the control circuit and includes the following steps: Collect real-time output electrical parameters of the solar film; Compare the real-time output electrical parameters with the reference electrical parameter values; When the real-time output electrical parameters are lower than the reference electrical parameter values, a screen adjustment drive signal is generated. The screen adjustment drive signal is output to the data drive interface of the electronic paper display panel to drive the electronic paper display panel to increase the number of black pixels displayed in the current screen.

[0059] In this embodiment, the step of generating the image adjustment drive signal is executed by the control circuit, specifically including: Obtain the original pixel dataset corresponding to the currently displayed screen. The original pixel dataset contains the original grayscale values ​​of each pixel. The selection priority is determined based on the original grayscale values ​​of each pixel from low to high, and at least a portion of the non-black pixels with the lowest original grayscale values ​​are selected as the pixels to be adjusted. The original grayscale values ​​of the pixels to be adjusted are replaced with the target grayscale values ​​corresponding to the black display state to generate the adjusted pixel dataset; The drive signal is adjusted based on the image generated from the adjusted pixel dataset.

[0060] 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: An electronic paper display panel has a display side and a non-display side that are arranged opposite to each other, with the non-display side being the backlight side; A solar film is installed on the non-display side of the electronic paper display panel. The solar film is used to receive light passing through the electronic paper display panel and convert light energy into electrical energy. The sampling circuit is electrically connected to the power output terminal of the solar film and is configured to collect the real-time output electrical parameters of the solar film. The comparison and judgment circuit is electrically connected to the signal output terminal of the sampling circuit. The comparison and judgment circuit is configured to receive real-time output electrical parameters and compare them with a reference electrical parameter value. When the real-time output electrical parameter is lower than the reference electrical parameter value, the comparison and judgment circuit outputs a trigger signal. The reference electrical parameter value is 40% to 60% of the average output power of the solar film in the electronic paper display device under normal display conditions. The control circuit has its signal input terminal electrically connected to the signal output terminal of the comparison and judgment circuit, and its drive signal output terminal electrically connected to the data drive interface of the electronic paper display panel. The control circuit is configured to output a screen adjustment drive signal to the data drive interface in response to receiving a trigger signal. The screen adjustment drive signal is used to drive the electronic paper display panel to increase the number of black pixels displayed in the current display screen. After the output screen adjustment drive signal is received, the control circuit continuously receives the real-time output electrical parameters fed back by the sampling circuit. When the real-time output electrical parameters recover to a value higher than the second reference electrical parameter value and the duration exceeds a predetermined time, the control circuit outputs a screen recovery drive signal to the data drive interface. The screen recovery drive signal is used to drive the electronic paper display panel to restore the current display screen to the display state before adjustment, or to gradually restore the black pixels to their respective original grayscale values ​​in multiple frames. The electronic paper display panel adopts a grayscale display driving architecture, which achieves different grayscale levels by configuring different numbers of black pixels in a pixel array composed of n×n pixels, where n is a positive integer greater than or equal to 2; the control circuit increases the number of black pixels displayed by reducing the display grayscale level of the current display screen.

2. The electronic paper display device according to claim 1, characterized in that, The sampling circuit includes: The sampling resistor is connected in series in the power output circuit of the solar film; The differential amplifier has its two input terminals connected to the two ends of the sampling resistor, and its output terminal serves as the signal output terminal of the sampling circuit. The differential amplifier is used to output a voltage sampling signal that characterizes the real-time output current of the solar film.

3. The electronic paper display device according to claim 1, characterized in that, The control circuit includes: The memory stores the pixel adjustment program. The processor is coupled to the memory and reads the pixel adjustment program. The processor's first input port is used as a signal input terminal, and the processor's data output port is used as a drive signal output terminal. When the processor executes the pixel adjustment program, it reads the original pixel dataset corresponding to the current display frame by frame. The original pixel dataset contains the original grayscale value of each pixel. The processor determines at least a portion of the non-black pixels from the original pixel dataset as pixels to be adjusted according to a preset selection strategy; The processor replaces the original grayscale value of the pixel to be adjusted with the target grayscale value corresponding to the black display state to generate the adjusted pixel dataset; The processor adjusts the drive signals based on the adjusted pixel dataset to generate the image.

4. The electronic paper display device according to claim 3, characterized in that, The preset selection strategy is specifically as follows: The processor determines the selection priority based on the original grayscale values ​​of each pixel from low to high, and prioritizes the non-black pixels with the lowest original grayscale values ​​as the pixels to be adjusted.

5. The electronic paper display device according to claim 3, characterized in that, The preset selection strategy is specifically as follows: The processor divides the current display screen into several pixel blocks, calculates the average value of the original grayscale values ​​of the pixels contained in each pixel block, and identifies all non-black pixels in the pixel block with the lowest average value as pixels to be adjusted.

6. The electronic paper display device according to claim 1, characterized in that, The comparison and judgment circuit includes: A reference voltage source is used to generate a reference voltage signal that corresponds to the reference electrical parameter value. The voltage comparator has its first input terminal electrically connected to the signal output terminal of the sampling circuit, its second input terminal electrically connected to the output terminal of the reference voltage source, and its output terminal serving as the signal output terminal of the comparison and judgment circuit.

7. A charging optimization method for an electronic paper display device, the electronic paper display device comprising an electronic paper display panel, a solar film, and a control circuit, wherein the control circuit is used to drive the electronic paper display panel, characterized in that, Applied to the electronic paper display device as described in any one of claims 1-6, the method is executed by a control circuit and includes the following steps: Collect real-time output electrical parameters of the solar film; Compare the real-time output electrical parameters with the reference electrical parameter values; When the real-time output electrical parameters are lower than the reference electrical parameter values, a screen adjustment drive signal is generated. The screen adjustment drive signal is output to the data drive interface of the electronic paper display panel to drive the electronic paper display panel to increase the number of black pixels displayed in the current screen.

8. The charging optimization method for an electronic paper display device according to claim 7, characterized in that, The step of adjusting the driving signal for generating the image is executed by the control circuit, specifically including: Obtain the original pixel dataset corresponding to the currently displayed screen, wherein the original pixel dataset contains the original grayscale value of each pixel; The selection priority is determined based on the original grayscale values ​​of each pixel from low to high, and at least a portion of the non-black pixels with the lowest original grayscale values ​​are selected as the pixels to be adjusted. The original grayscale values ​​of the pixels to be adjusted are replaced with the target grayscale values ​​corresponding to the black display state to generate the adjusted pixel dataset; The drive signal is adjusted based on the image generated from the adjusted pixel dataset.

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