Perovskite photovoltaic panel self-powered liquid crystal handwriting panel

Abstract

The utility model discloses a perovskite photovoltaic panel self -power liquid crystal handwriting board, including cover, backboard, liquid crystal handwriting diaphragm, PCB board, perovskite photovoltaic panel, prevent reverse diode and super capacitor, cover fixed mounting is in backboard, perovskite photovoltaic panel's negative pole connects super capacitor's negative pole, perovskite photovoltaic panel's positive pole is connected super capacitor's positive pole through prevent reverse diode, and the conduction direction of prevent reverse diode is configured as by perovskite photovoltaic panel points to super capacitor, super capacitor's positive pole connects PCB board's power supply interface's positive pole, super capacitor's negative pole connects PCB board's power supply interface's negative pole, and PCB board is connected with liquid crystal handwriting diaphragm electricity, first window and second window are seted up on the cover. The utility model discloses the collocation of perovskite photovoltaic panel and super capacitor, can make full use of indoor weak light environment to provide the electric energy for super capacitor stably to meet the electric energy use demand required when the intermittent screen of liquid crystal handwriting board is brushed.

Description

Technical Field

[0001] This utility model belongs to the field of liquid crystal writing tablets, and more specifically, relates to a perovskite photovoltaic self-powered liquid crystal writing tablet. Background Technology

[0002] With the popularization of paperless office concepts and the improvement of environmental awareness, LCD writing tablets (also known as electronic writing tablets or light-powered blackboards) have become a new type of writing tool that replaces traditional paper, pen, chalk, and blackboards. They are widely used in children's education, business offices, family message boards, and medical teaching. The core display principle of LCD writing tablets is usually based on bistable cholesteric liquid crystal technology. Its characteristic is that writing consumes virtually no power, and clearing the screen consumes only a small amount of power. Users change the arrangement of liquid crystal molecules through pen tip pressure to display handwriting. When clearing handwriting, a momentary pulse voltage is output from the motherboard to drive the liquid crystal molecules to rearrange and return to their initial state.

[0003] Despite the low power consumption advantage of LCD handwriting tablets, existing power supply solutions still face severe technical bottlenecks in practical applications, which seriously restricts the further promotion of the products and the user experience.

[0004] Currently, the vast majority of LCD handwriting tablets on the market primarily use button batteries (such as CR2016, CR2025, CR2032, etc.) or rechargeable lithium-ion batteries as their power source. Button batteries are disposable consumables; although the cost per unit is low, their replacement frequency is often criticized by users. Once the battery is depleted, if the user does not replace it in time, the handwriting tablet becomes unusable. More seriously, if discarded button batteries are not disposed of properly, the heavy metal components inside can cause long-term pollution to soil and water sources, which runs counter to the environmentally friendly and paperless concepts promoted by LCD handwriting tablets.

[0005] While some high-end products utilize rechargeable lithium batteries, this introduces more complex charge / discharge management circuitry and physical interfaces (such as Type-C or Micro-USB interfaces), significantly increasing BOM (Bill of Materials) costs and product thickness. As a chemical energy storage medium, lithium batteries inherently exhibit self-discharge and limited cycle life. In devices like writing tablets that may be idle for extended periods, lithium batteries often suffer from increased internal resistance, irreversible capacity degradation, and even bulging due to prolonged over-discharge, causing the product to malfunction after only one or two years of use.

[0006] To address the hassles of battery replacement and charging, some existing technologies attempt to incorporate solar panels (photovoltaics) for power generation. However, these attempts mostly utilize traditional amorphous silicon (a-Si) or monocrystalline / polycrystalline silicon (c-Si) photovoltaic modules, which perform poorly in real-world scenarios. LCD writing tablets are primarily used indoors (such as classrooms, offices, and living rooms), where ambient light intensity is typically between 500 and 800 lux, and the light source is often LED or fluorescent lamps. Traditional crystalline silicon cells are mainly optimized for the high-intensity outdoor solar spectrum (AM1.5), and their bandgap is not suitable for the spectral response of indoor artificial light sources. This leads to a sharp drop in the photoelectric conversion efficiency of traditional silicon-based photovoltaic panels under indoor lighting conditions, often failing to generate sufficient voltage and current to drive screen clearing operations. Furthermore, in insufficient light or dark environments, the charge in the energy storage elements is prone to reverse leakage to the photovoltaic panel (dark current effect). The dark current effect not only wastes energy but also causes the energy storage elements to become depleted and damaged due to long-term reverse discharge, accelerating the performance degradation of the photovoltaic panel. Many solar-powered writing tablets still use miniature rechargeable lithium batteries as energy storage mediums. Lithium batteries have many defects in charging and discharging, such as short cycle life and poor tolerance to long-term repeated charging and discharging. The cycle life of conventional lithium batteries is only 300 to 500 times. When solar photovoltaic panels charge lithium batteries, the voltage fluctuations are large, which can easily lead to overcharging, swelling, electrolyte decomposition, and even fire. Utility Model Content

[0007] In view of the above-mentioned defects or improvement needs of the existing technology, this utility model provides a perovskite photovoltaic self-powered liquid crystal writing board. By combining the perovskite photovoltaic panel with a supercapacitor, it can make full use of the indoor low light environment, thereby stably providing power for the use of the liquid crystal writing board.

[0008] To achieve the above objectives, according to this utility model, a self-powered liquid crystal writing board with a perovskite photovoltaic panel is provided, comprising a cover plate, a back plate, a liquid crystal writing film, a PCB board, a perovskite photovoltaic panel, an anti-reverse diode, and a supercapacitor, wherein: The cover plate is fixedly installed on the back plate. The liquid crystal handwriting film, PCB board, perovskite photovoltaic panel and supercapacitor are disposed in the inner cavity of the back plate. The negative terminal of the perovskite photovoltaic panel is connected to the negative terminal of the supercapacitor. The positive terminal of the perovskite photovoltaic panel is connected to the positive terminal of the supercapacitor through the anti-reverse diode. The conduction direction of the anti-reverse diode is configured to point from the perovskite photovoltaic panel to the supercapacitor. The positive terminal of the supercapacitor is connected to the positive terminal of the power interface of the PCB board. The negative terminal of the supercapacitor is connected to the negative terminal of the power interface of the PCB board. The PCB board is electrically connected to the liquid crystal handwriting film. The cover plate has a first window at a position corresponding to the liquid crystal handwriting film to expose the liquid crystal handwriting film; The cover plate has a second window at a position corresponding to the perovskite photovoltaic panel to expose the perovskite photovoltaic panel.

[0009] Preferably, the inner cavity of the back plate is provided with a partition, which divides the inner cavity of the back plate into a liquid crystal handwriting film receiving cavity and a circuit module receiving cavity. The liquid crystal handwriting film is disposed in the liquid crystal handwriting film receiving cavity, and the PCB board, perovskite photovoltaic panel, anti-reverse diode and supercapacitor are all located in the circuit module receiving cavity.

[0010] Preferably, the back plate and the cover plate are fixedly connected together by a snap fastener, and the cover plate and the back plate cooperate to clamp the liquid crystal handwriting film.

[0011] Preferably, it also includes a stylus, and the cover plate or back plate is provided with a magnet for attracting the stylus.

[0012] Preferably, under indoor illumination conditions of 500 lux to 800 lux, the power of the perovskite photovoltaic panel is 1 mW to 1.8 mW, the open-circuit voltage is ≥5 V, and the voltage at the maximum power point is 3 V ± 0.5 V; The supercapacitor has a capacitance of 10F to 100F and an operating voltage of 3V to 3.8V. The voltage at the maximum power point of the perovskite photovoltaic panel is not greater than the operating voltage of the supercapacitor.

[0013] Preferably, the perovskite photovoltaic panel includes multiple sub-cell units formed by laser etching process, and these sub-cell units are connected in series.

[0014] Preferably, the perovskite photovoltaic panel is rectangular, and the effective light-receiving area of ​​the perovskite photovoltaic panel is ≤15cm². 2 The number of sub-battery units is 14.

[0015] Preferably, the liquid crystal handwriting film is mounted on the back plate via an acrylic plate, and the liquid crystal handwriting film is adhered to the acrylic plate.

[0016] Preferably, the cover plate is provided with a third window to expose the screen clearing button that is electrically connected to the PCB board.

[0017] Preferably, the back panel is provided with a fourth window for displaying the toggle switch electrically connected to the PCB board.

[0018] In summary, compared with the prior art, the above-described technical solution conceived by this utility model can achieve the following beneficial effects: 1) This invention relates to a self-powered liquid crystal writing tablet powered by a perovskite photovoltaic panel. The perovskite photovoltaic panel exhibits extremely high light absorption coefficient and a long carrier diffusion distance in low-light environments. This means that under normal indoor illuminance, the liquid crystal writing tablet can continuously generate sufficient photocurrent to drive the circuitry. By installing the perovskite photovoltaic panel within the back panel cavity and exposing it through a second window on the cover, the liquid crystal writing tablet can receive external photons and convert light energy into electrical energy. This photoelectric conversion mechanism does not rely on external power lines or frequently replaced chemical batteries. Instead, it establishes a continuous energy extraction channel that automatically operates according to ambient light, achieving a highly efficient response to the indoor visible light spectrum (especially LED light sources and fluorescent lamp spectra), ensuring that the liquid crystal writing tablet can maintain its energy reserves even in the presence of light.

[0019] 2) This utility model discloses a perovskite photovoltaic self-powered LCD handwriting tablet, which uses a supercapacitor as the energy storage medium, improving the adaptability of the LCD handwriting tablet to the specific load characteristic of screen clearing. Based on the double-layer energy storage principle, the supercapacitor has extremely low equivalent series resistance and extremely high power density, easily handling the large current pulse demand during screen clearing, ensuring thorough clearing without afterimages. Simultaneously, the physical energy storage mechanism of the supercapacitor gives it a long charge-discharge cycle life and a wide operating temperature range, maintaining stable physicochemical properties in extremely cold or high-temperature environments.

[0020] 3) In this utility model, a self-powered LCD handwriting board using a perovskite photovoltaic panel has an anti-reverse diode connected between the perovskite photovoltaic panel and the supercapacitor. The conduction direction is from the perovskite photovoltaic panel to the supercapacitor. This allows the anti-reverse diode to effectively block the return current path from the supercapacitor to the perovskite photovoltaic panel (i.e., prevent dark current leakage) by utilizing the unidirectional conductivity of its PN junction in dark or extremely low light environments when the voltage of the perovskite photovoltaic panel is lower than the terminal voltage of the supercapacitor. This effectively locks in the stored charge in the supercapacitor, ensuring that the electrical energy in the supercapacitor only enters and does not leave, greatly extending the standby time of the LCD handwriting board. Attached Figure Description

[0021] Figure 1 , Figure 2 These are perspective views of this utility model from different angles; Figure 3 This is a schematic diagram of the structure of this utility model after the cover plate is removed; Figure 4 This is a partial structural schematic diagram of the present invention; Figure 5 This is an exploded view of this utility model.

[0022] In all the accompanying drawings, the same reference numerals denote the same technical features, specifically: 1. Back panel; 2. Magnet; 3. LCD handwriting membrane; 4. Clear screen button; 5. Perovskite photovoltaic panel; 6. PCB board; 7. Screw; 8. Supercapacitor; 9. Anti-reverse diode; 10. PCB board clip; 11. Cover plate; 12. Toggle switch; 13. Acrylic board; 14. First window; 15. Second window; 16. Third window; 17. Fourth window. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model. Furthermore, the technical features involved in the various embodiments of the present utility model described below can be combined with each other as long as they do not conflict with each other.

[0024] Reference Figures 1-5 A self-powered liquid crystal handwriting board based on a perovskite photovoltaic panel includes a cover plate 11, a back plate 1, a liquid crystal handwriting film 3, a PCB board 6, a perovskite photovoltaic panel 5, an anti-reverse diode 9, and a supercapacitor 8.

[0025] The cover plate 11 is fixedly installed on the back plate 1. The liquid crystal handwriting film 3, PCB board 6, perovskite photovoltaic panel 5 and supercapacitor 8 are disposed in the inner cavity of the back plate 1. The PCB board 6 is preferably limited by the PCB board clip 10 on the back plate 1 and then fixed to the back plate 1 by screws 7. The liquid crystal handwriting film 3, PCB board 6, perovskite photovoltaic panel 5 are fixed to the back plate 1. The negative terminal of the perovskite photovoltaic panel 5 is connected to the negative terminal of the supercapacitor 8. The positive terminal of the perovskite photovoltaic panel 5 is connected to the positive terminal of the supercapacitor 8 through the anti-reverse diode 9. The conduction direction of the anti-reverse diode 9 is configured to point from the perovskite photovoltaic panel 5 to the supercapacitor 8. The positive terminal of the supercapacitor 8 is connected to the positive terminal of the power interface of the PCB board 6. The negative terminal of the supercapacitor 8 is connected to the negative terminal of the power interface of the PCB board 6. The PCB board 6 is electrically connected to the liquid crystal handwriting film 3.

[0026] The cover plate 11 has a first window 14 at a position corresponding to the liquid crystal handwriting film 3, so as to expose the liquid crystal handwriting film 3.

[0027] The cover plate 11 has a second window 15 at a position corresponding to the perovskite photovoltaic panel 5 to expose the perovskite photovoltaic panel 5.

[0028] This invention uses a perovskite photovoltaic panel 5 to continuously receive sunlight to charge a supercapacitor 8, making full use of the low-light indoor environment.

[0029] A sliding plate can be installed on the cover plate 11 at the position corresponding to the first window 14. If the supercapacitor 8 is fully charged (an additional power display module can be configured to display the power level), the sliding plate can cover the perovskite photovoltaic panel 5, preventing it from receiving sunlight and thus preventing the supercapacitor 8 from overcharging. Alternatively, the electrical parameters of the perovskite photovoltaic panel 5 and the supercapacitor 8 can be adapted. For example, the maximum power point voltage of the perovskite photovoltaic panel 5 can be made no greater than the operating voltage of the supercapacitor 8. Even if the perovskite photovoltaic panel 5 is constantly under sunlight and generating electricity, its stable output voltage will never exceed the safe operating voltage range of the supercapacitor 8. When the voltage across the supercapacitor 8 reaches a level that balances with the open-circuit voltage of the perovskite photovoltaic panel 5, the potential difference is zero, and the current will automatically cut off. Therefore, the voltage generated by the perovskite photovoltaic panel 5 is insufficient to cause the supercapacitor 8 to overflow or break down.

[0030] This invention integrates the liquid crystal writing membrane 3, PCB board 6, perovskite photovoltaic panel 5, and supercapacitor 8 into the inner cavity of the back plate 1, and encapsulates them with a cover plate 11. This structure greatly improves space utilization. The back plate 1 acts as a supporting base for each functional module, providing stable mechanical support. The cover plate 11, through the opening of the first window 14 and the second window 15, physically protects the internal precision components while precisely defining the user's interaction area (the writing area of ​​the liquid crystal writing membrane 3) and the energy harvesting area (the light-receiving area of ​​the perovskite photovoltaic panel 5). This integrated structural design allows the liquid crystal writing tablet to maintain a slim appearance while achieving complete functionality. Furthermore, the relatively fixed positions of each component significantly enhance its vibration and drop resistance, effectively preventing poor circuit contact or component displacement caused by external impacts.

[0031] The PCB board 6 connects the supercapacitor 8 and the liquid crystal handwriting membrane 3, serving as a hub for energy distribution and logic control. It receives DC power from the supercapacitor 8 and, based on user commands (such as a screen clearing signal), converts the DC power into high-voltage pulse signals required to drive the liquid crystal molecules. The presence of the PCB board 6 makes energy utilization more intelligent and precise, enabling accurate control of the amplitude and pulse width of the screen clearing voltage. This further reduces energy consumption per operation while ensuring effective screen clearing, optimizing the overall energy efficiency ratio. Both the PCB board 6 and the liquid crystal handwriting membrane 3 are standard market products. This invention solves the charging and energy storage problems of existing handwriting boards simply by adapting the perovskite photovoltaic panel 5, the anti-reverse diode 9, and the supercapacitor 8, without requiring modification to the existing circuit structure.

[0032] Furthermore, the inner cavity of the back plate 1 is provided with a partition, which divides the inner cavity of the back plate 1 into a liquid crystal handwriting film receiving cavity and a circuit module receiving cavity. The liquid crystal handwriting film 3 is disposed in the liquid crystal handwriting film receiving cavity, and the PCB board 6, perovskite photovoltaic panel 5, anti-reverse diode 9, and supercapacitor 8 are all located in the circuit module receiving cavity. The partition physically separates the liquid crystal handwriting area from the circuit control area (including the PCB board 6, perovskite photovoltaic panel 5, supercapacitor 8, etc.), effectively avoiding mutual interference between modules. It clearly defines the installation area of ​​each component, enabling rapid positioning when assembling the liquid crystal handwriting film 3 and the circuit module. The circuit module receiving cavity can be further divided into different functional areas by partitions.

[0033] Furthermore, the back plate 1 and the cover plate 11 are fixedly connected together by snap-fit, and the cover plate 11 and the back plate 1 cooperate to clamp the liquid crystal handwriting film 3. The snap-fit ​​connection can achieve locking by utilizing the elastic deformation of the material itself. This design significantly simplifies the assembly process and shortens the production cycle. The cover plate 11 and the back plate 1 cooperate to clamp the liquid crystal handwriting film 3. This uniform clamping force effectively prevents the flexible liquid crystal handwriting film 3 from shifting, wrinkling, or lifting at the edges during long-term use, ensuring the absolute flatness and tightness of the writing surface, thereby guaranteeing the clarity of the handwriting display and the smooth touch of writing.

[0034] Furthermore, it also includes a stylus, and the cover plate 11 or back plate 1 is provided with a magnet 2 for adsorbing the stylus. By setting the magnet 2 on the cover plate 11 or back plate 1, the stylus with its built-in metal component or magnet is firmly adsorbed by the magnetic field. This fixing method eliminates the need for complex pen slots or clips on the cover plate 11 or back plate 1, maintaining the slimness and integrity of the body. The magnetic attraction provides the convenience of blind operation. After use, the user only needs to bring the stylus close to the adsorption area, and the stylus will automatically return to its position. This greatly reduces the probability of the stylus accidentally slipping or being lost, improving portability.

[0035] Furthermore, under indoor illumination conditions of 500 lux to 800 lux (typical indoor office lighting), the power of the perovskite photovoltaic panel 5 is 1 mW to 1.8 mW, the open-circuit voltage is ≥5 V, and the voltage at the maximum power point is 3 V ± 0.5 V.

[0036] The supercapacitor 8 has a capacitance of 10F to 100F and an operating voltage of 3V to 3.8V. The voltage at the maximum power point of the perovskite photovoltaic panel is not greater than the operating voltage of the supercapacitor.

[0037] If the supercapacitor 8 has too small a capacity, the product's battery life will be insufficient; if the capacity is too large, it will prolong the time it takes to charge the product to the startup voltage; if the operating voltage is too high, it will damage the circuit. The supercapacitor 8 has a voltage stabilization function, which can prevent the output voltage from damaging the PCB board 6; at the same time, the output voltage of the perovskite photovoltaic panel 5 is controlled within a safe range, which can achieve safe charging of the supercapacitor 8.

[0038] The 500lux~800lux setting precisely targets the lighting environment most commonly used by LCD writing tablets, ensuring that the perovskite photovoltaic panel 5 operates within its most efficient energy conversion range under this illuminance. Compared to blindly pursuing high power, this parameter optimization for a specific illuminance range maximizes the material utilization of the photovoltaic module, avoids dead zones in low light, and guarantees continuous and stable micro-current output. The maximum power point voltage is set at 3V±0.5V, and the supercapacitor 8's operating voltage is 3V~3.8V. The high degree of overlap between these two voltage parameters achieves the effect of direct voltage drive technology. That is, the voltage generated by the perovskite photovoltaic panel 5 can directly charge the supercapacitor 8 without going through a complex boost or buck converter. The maximum power point voltage of the perovskite photovoltaic panel 5 does not exceed the operating voltage of the supercapacitor 8, preventing overcharging of the supercapacitor 8.

[0039] For an LCD handwriting tablet that consumes only microjoules of energy per screen clearing operation, the supercapacitor 8 with a capacitance of 10F or more provides a very high capacity. This allows the LCD handwriting tablet to support many screen clearing operations or standby time of up to several weeks, even in a completely dark environment after a full charge. The high-capacity supercapacitor 8 also smooths out voltage fluctuations caused by light variations, providing an extremely stable DC power supply for the PCB board 6.

[0040] The current-voltage characteristic curve can reflect the relationship between the output voltage and current of the perovskite photovoltaic panel 5 under indoor conditions. Through adjustment, the voltage and current output states of the perovskite photovoltaic panel 5 within a fixed effective illumination area are made to best match the charging requirements of the supercapacitor 8, ensuring optimal charging efficiency under indoor conditions.

[0041] To ensure the LCD writing tablet can be used more than 500 times, has a battery life of over 30 days in the dark, and only needs 8 hours to meet its operational requirements when completely out of power, experiments were conducted to test the daily power consumption of the LCD writing tablet. Based on the principle of the LCD writing tablet, the experimenters pressed the clear screen button 4 approximately 500 times, each time for 1 second, and the average power consumption was 0.5mWh. Considering that users would not use the writing tablet for a maximum of 30 days, the capacity and voltage of the supercapacitor 8 were determined. Based on the thickness and size of a typical writing tablet, the final selection was a 20F capacity and a 3.8V operating voltage for the supercapacitor 8. According to actual measurements, the total capacity of the supercapacitor 8 is 15mAh, the daily self-discharge is ≤0.2mWh, and the power loss after 30 days of non-use is 6mWh. The remaining voltage is still higher than the starting voltage of 1.8V, and it can meet the requirements of more than 500 screen clearing cycles. Corresponding to the parameters of the supercapacitor 8, the power of the perovskite photovoltaic panel 5 is selected as 1mW. Under 600lux illumination, the open circuit voltage of the perovskite photovoltaic panel 5 is ≥5V, and the maximum power point voltage is 3V±0.5V.

[0042] Furthermore, the perovskite photovoltaic panel 5 includes multiple sub-cell units formed by laser etching process, and these sub-cell units are connected in series.

[0043] The entire perovskite photovoltaic panel 5 is cut and connected in series into multiple sub-cell units by laser etching. Utilizing the principle of voltage addition in a series circuit, the small-area perovskite photovoltaic panel 5 can directly output a relatively high operating voltage. Laser etching is a commonly used process in the manufacturing of perovskite photovoltaic panels 5, and will not be elaborated upon here.

[0044] Furthermore, the perovskite photovoltaic panel 5 is rectangular, and the effective light-receiving area of ​​the perovskite photovoltaic panel 5 is ≤15cm². 2 The number of sub-battery units is 14.

[0045] The rectangular geometric shape fits the narrow bezel area of ​​the writing tablet. This design allows the perovskite photovoltaic panel 5 to be embedded in the non-display area of ​​the product, achieving the integration of the perovskite photovoltaic panel 5 without sacrificing the core writing area (screen ratio). The perovskite photovoltaic panel 5 is ≤15cm in diameter. 2 The area limitation ensures sufficient power output while controlling material costs and product size.

[0046] The limit of 14 sub-cells is based on precise calculations of the bandgap characteristics of perovskite materials. This specific number of cells in series is designed to ensure that the maximum power point voltage (Vmpp) of the perovskite photovoltaic panel 5 falls precisely within the optimal charging window of the supercapacitor 8 under the most common indoor light intensities, thereby achieving passive maximum power matching without the need for an MPPT (maximum power point tracking) chip.

[0047] Furthermore, the liquid crystal handwriting film 3 is mounted on the back plate 1 via an acrylic plate 13, and the liquid crystal handwriting film 3 is adhered to the acrylic plate 13. The acrylic plate 13 has excellent hardness and surface flatness. Adhering the flexible liquid crystal film to the rigid acrylic plate 13 provides solid physical support for writing, which eliminates the feeling of collapse when writing directly on the soft liquid crystal handwriting film 3, making the pen touch feedback more firm and clear.

[0048] Furthermore, a third window 16 is provided on the cover plate 11 to expose the screen clearing button 4, which is electrically connected to the PCB board 6. The third window 16 provides precise physical positioning for the screen clearing button. The edge of the third window 16 forms a track for the button's movement, preventing the screen clearing button 4 from shaking or deflecting during pressing, and ensuring that the pressing force can be transmitted vertically and accurately to the PCB board 6.

[0049] Furthermore, a fourth window 17 is provided on the back panel 1 to expose the toggle switch electrically connected to the PCB board 6. The length of the fourth window is precisely matched to the mechanical travel of the toggle switch 12. The two end walls of the window naturally form the stop positions for the switch toggle. When the user forcefully toggle the switch 12, the force is applied to the window wall of the back panel 1.

[0050] This invention, through the compatible combination of a perovskite photovoltaic panel 5 and a supercapacitor 8, can stably provide the energy required for the operation of an LCD handwriting tablet, ensuring that the product can clear the screen more than 500 times per day. The supercapacitor 8 allows the handwriting tablet to last for more than 30 days without light or use, and compared with conventional lithium batteries, the supercapacitor 8 has a higher charging efficiency. After being depleted, it can be fully charged in 12 hours indoors, and after charging, it can support more than 500 screen clears. In addition, the perovskite photovoltaic panel 5 and the supercapacitor 8 are small in size and occupy little internal space on the handwriting tablet, thus avoiding wasted product space. At the same time, the charge-discharge cycle life of the supercapacitor 8 is much longer than that of conventional lithium batteries, and it will not be damaged after multiple charge-discharge cycles, effectively improving the overall lifespan of the product.

[0051] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A self-powered liquid crystal handwriting tablet based on a perovskite photovoltaic panel, characterized in that, This includes a cover plate, back plate, LCD handwriting film, PCB board, perovskite photovoltaic panel, anti-reverse diode, and supercapacitor, among which: The cover plate is fixedly installed on the back plate. The liquid crystal handwriting film, PCB board, perovskite photovoltaic panel and supercapacitor are disposed in the inner cavity of the back plate. The negative terminal of the perovskite photovoltaic panel is connected to the negative terminal of the supercapacitor. The positive terminal of the perovskite photovoltaic panel is connected to the positive terminal of the supercapacitor through the anti-reverse diode. The conduction direction of the anti-reverse diode is configured to point from the perovskite photovoltaic panel to the supercapacitor. The positive terminal of the supercapacitor is connected to the positive terminal of the power interface of the PCB board. The negative terminal of the supercapacitor is connected to the negative terminal of the power interface of the PCB board. The PCB board is electrically connected to the liquid crystal handwriting film. The cover plate has a first window at a position corresponding to the liquid crystal handwriting film to expose the liquid crystal handwriting film; The cover plate has a second window at a position corresponding to the perovskite photovoltaic panel to expose the perovskite photovoltaic panel.

2. The perovskite photovoltaic self-powered liquid crystal handwriting tablet according to claim 1, characterized in that, The inner cavity of the back plate is provided with a partition, which divides the inner cavity of the back plate into a liquid crystal handwriting film receiving cavity and a circuit module receiving cavity. The liquid crystal handwriting film is disposed in the liquid crystal handwriting film receiving cavity, and the PCB board, perovskite photovoltaic panel, anti-reverse diode and supercapacitor are all located in the circuit module receiving cavity.

3. The perovskite photovoltaic self-powered liquid crystal handwriting tablet according to claim 1, characterized in that, The back plate and the cover plate are fixedly connected together by a snap fastener, and the cover plate and the back plate cooperate to clamp the liquid crystal handwriting film.

4. The perovskite photovoltaic self-powered liquid crystal handwriting tablet according to claim 1, characterized in that, It also includes a stylus, and the cover or back plate is provided with magnets for attracting the stylus.

5. A perovskite photovoltaic self-powered liquid crystal handwriting tablet according to claim 1, characterized in that, Under indoor illumination conditions of 500 lux to 800 lux, the power of perovskite photovoltaic panels is 1 mW to 1.8 mW, the open-circuit voltage is ≥5 V, and the voltage at the maximum power point is 3 V ± 0.5 V. The supercapacitor has a capacitance of 10F to 100F and an operating voltage of 3V to 3.8V. The voltage at the maximum power point of the perovskite photovoltaic panel is not greater than the operating voltage of the supercapacitor.

6. A perovskite photovoltaic self-powered liquid crystal handwriting tablet according to claim 5, characterized in that, The perovskite photovoltaic panel includes multiple sub-cell units formed by laser etching, and these sub-cell units are connected in series.

7. A perovskite photovoltaic self-powered liquid crystal handwriting tablet according to claim 6, characterized in that, The perovskite photovoltaic panel is rectangular, and its effective light-receiving area is ≤15cm². 2 The number of sub-battery units is 14.

8. A self-powered liquid crystal handwriting tablet based on a perovskite photovoltaic panel according to claim 1, characterized in that, The liquid crystal handwriting film is mounted on the back plate via an acrylic plate, and the liquid crystal handwriting film is adhered to the acrylic plate.

9. A perovskite photovoltaic self-powered liquid crystal handwriting tablet according to claim 1, characterized in that, The cover plate is provided with a third window to expose the screen clear button that is electrically connected to the PCB board.

10. A perovskite photovoltaic self-powered liquid crystal handwriting tablet according to claim 1, characterized in that, The back panel has a fourth window for displaying the toggle switch that is electrically connected to the PCB board.

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