Liquid crystal writing film with white handwriting and liquid crystal blackboard

Abstract

The utility model provides a liquid crystal writing film for white handwriting. The liquid crystal writing film with the white handwriting at least comprises two liquid crystal layers, and white display of the written handwriting is achieved through specific design.

Description

Technical Field

[0001] This utility model relates to the field of liquid crystal writing film technology, and in particular to a liquid crystal writing film with white writing and a liquid crystal blackboard. Background Technology

[0002] Currently, most commercially available LCD writing tablets are based on the optical properties of cholesteric liquid crystals, achieving diverse writing colors by reflecting light of different wavelengths. These devices can produce a variety of colors from red to purple within the visible light range and typically use a black background to enhance the visual contrast of the handwriting. However, standard LCD blackboards are usually limited to displaying a single color, or achieving multiple color effects in specific areas by reflecting different wavelengths of liquid crystal, which is insufficient to achieve the versatility of switching colors in any writing area.

[0003] In existing technologies, although solutions have been developed to switch colors in any writing area by stacking multiple liquid crystal film layers, where each liquid crystal layer includes two conductive layers and one liquid crystal layer, and is controlled by specific circuits to reflect light of different wavelengths, thus achieving multi-color switching and displaying a multi-color effect, the handwriting color band of the LCD writing tablet is between red and violet light. Combined with a black background, the contrast of the handwriting is not strong enough, resulting in the handwriting not being clearly visible when the user is at a distance. Currently, neither monochrome nor multi-color LCD writing tablets can fully achieve the full-color handwriting effect of traditional blackboards, especially the type with black background and white text. Even multi-color LCD writing tablets can only switch colors between red and violet, lacking white text. The technology of using multiple liquid crystal film layers to achieve multi-color LCD blackboards has a drawback: when certain multiple colors are written simultaneously, only the color of the surface liquid crystal layer is displayed. To achieve more color effects, more layers need to be stacked, which greatly increases production costs and reduces production yield.

[0004] Therefore, although existing multi-color LCD writing tablet technology has achieved colorful display to some extent, it still suffers from problems such as insufficient color contrast, lack of white text, and high production costs. These issues limit its widespread adoption in practical applications and the improvement of user experience. Developing a new type of LCD writing tablet to address these limitations is therefore crucial and necessary. Utility Model Content

[0005] The main objective of this invention is to propose a liquid crystal writing film for white text, aiming to solve the current technical problems of insufficient color contrast, lack of white text, and high production costs. This novel liquid crystal writing film, through innovative design and technical means, can effectively improve display effects and user experience while reducing manufacturing costs, bringing significant technological innovation and application value to related fields.

[0006] To achieve the above objectives, this utility model proposes a liquid crystal writing film with white text. The liquid crystal writing film with white text comprises at least two liquid crystal layers, and the writing on the film is white. The reflectivity of the liquid crystal layers within the film gradually increases from the surface to the bottom. This design makes the written content more clearly visible, especially against a dark background, where the white text has higher contrast, making it easier to read and recognize, thereby improving the user experience.

[0007] The liquid crystal writing film proposed in this invention has a wavelength distribution range between 400nm and 700nm, making it suitable for a wide range of display and writing applications. This gives the liquid crystal writing film broad application potential in various scenarios such as education, office, and home.

[0008] Furthermore, the liquid crystal writing film for white writing comprises two liquid crystal layers. From top to bottom, the film structure consists of an AG layer, a first substrate layer, a first conductive film layer, a first liquid crystal layer, a second conductive film layer, a second substrate layer, a first adhesive layer, a third substrate layer, a third conductive film layer, a second liquid crystal layer, a fourth conductive film layer, a fourth substrate layer, a second adhesive layer, and a base layer. When the liquid crystal writing film contains two liquid crystal layers, the reflectivity percentage of the surface liquid crystal layer is 15%–45%, while the reflectivity percentage of the bottom liquid crystal layer is 55%–85%. This design not only optimizes the visual effect of writing but also improves the visibility and contrast of the writing. The color combination reflected by the two liquid crystal layers is one of the following: red and cyan, green and magenta, blue and yellow, orange and light blue, yellow-green and purple, or pink and light cyan.

[0009] Furthermore, the control circuit is a microprocessor control unit, which uses software programming to precisely control each conductive area, thereby adjusting the transmittance and reflectivity of different liquid crystal layers. The use of a microprocessor greatly improves the system's intelligence level, making the operation of the liquid crystal writing film simpler and faster, while also providing possibilities for future functional expansion and upgrades.

[0010] Furthermore, the first, second, and third substrate layers are made of transparent polymer materials, while the fourth substrate layer can be transparent or black. The use of transparent polymer materials ensures the overall transparency and aesthetics of the writing film, while the black fourth substrate can be selected according to actual needs to meet different usage scenarios and aesthetic requirements.

[0011] Furthermore, the base layer is a rigid backplate, providing structural support and protecting the internal circuitry from external influences. The use of a rigid backplate not only enhances the stability and durability of the writing membrane but also effectively prevents the internal circuitry from being affected and damaged by the external environment, extending the product's lifespan.

[0012] This invention also proposes a liquid crystal blackboard, wherein the liquid crystal blackboard is equipped with a pen color changing device. This pen color changing device is electrically connected to the control circuit, and the desired pen color can be easily changed through the pen color changing device.

[0013] In addition, the LCD blackboard also includes an erasure position positioning device. This erasure position positioning device is also electrically connected to the control circuit, and can accurately locate and erase the position of the writing to be erased.

[0014] The LCD blackboard also includes a handwriting storage unit and a communication unit for transmitting signals to the outside.

[0015] Wherein: the handwriting storage unit is used to record the content written by the user on the LCD blackboard, including information such as the color, shape, position and timestamp of the handwriting, so as to view or restore it later; the communication unit supports wireless communication protocols, enabling the LCD blackboard to exchange data with other smart devices;

[0016] The LCD blackboard can receive signals or instructions from external devices through the communication unit.

[0017] The communication unit can export the data stored in the handwriting storage unit to an external storage medium or a cloud server to achieve data backup and sharing.

[0018] The communication unit also enables the LCD blackboard to have remote control functionality, allowing users to operate and manage the blackboard from different locations via a dedicated application.

[0019] The communication unit supports real-time synchronization to ensure information consistency between multiple LCD blackboards or between the LCD blackboard and mobile devices.

[0020] This application provides a white liquid crystal writing film and its matching liquid crystal blackboard, which has the following features:

[0021] Beneficial effects:

[0022] 1. Enhanced Display: By designing white lettering, the written content is made more clearly visible against a dark background. This high-contrast design significantly improves the user experience, especially in low-light environments.

[0023] 2. Multi-layer structure design: The liquid crystal writing film adopts a multi-layer structure, which not only ensures the product's strength and durability but also enables precise control and management of light. This structural design effectively extends the product's lifespan and ensures the stability of the display effect.

[0024] 3. Intelligent Operation: Both the LCD writing film and the LCD blackboard are equipped with control circuits and microprocessors, allowing users to precisely control each conductive area through software programming. This greatly enhances the functionality and flexibility of the writing film, making operation simpler and faster.

[0025] 4. Color adjustable: The LCD blackboard is equipped with a handwriting color adjustment device, which allows users to easily change the desired handwriting color to meet the writing needs of different scenarios.

[0026] 5. Precise erasure function: Equipped with an erasure position positioning device, it can accurately locate and erase the desired writing position, improving the convenience and efficiency of use.

[0027] 6. Data Recording and Backup: The LCD blackboard also includes a handwriting storage unit, which can record all content written by the user, including information such as color, shape, position, and timestamp. This data can be exported to external storage media or a cloud server via the communication unit, enabling data backup and sharing.

[0028] 7. Remote Control and Real-Time Synchronization: The communication unit supports wireless communication protocols, enabling the LCD blackboard to exchange data with other smart devices and providing remote control functionality. Users can operate and manage the blackboard from different locations using a dedicated application. Furthermore, the communication unit supports real-time synchronization, ensuring information consistency between multiple LCD blackboards or between the LCD blackboard and mobile devices.

[0029] 8. Wide range of applications: Due to its excellent display effect, durability and intelligent features, this liquid crystal writing film and liquid crystal blackboard are suitable for a variety of application scenarios, such as education, office and home, and have a wide range of applications.

[0030] In summary, this application, through innovative design and technical means, significantly improves the performance and user experience of liquid crystal writing films and liquid crystal blackboards, providing users with a more efficient, convenient, and intelligent solution. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of a liquid crystal writing film for white characters in one embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of the structure of a liquid crystal writing film for white characters in another embodiment of the present invention;

[0033] Figure 3 This is a circuit module diagram of a liquid crystal blackboard according to one embodiment of the present invention. Detailed Implementation

[0034] The solutions in the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this utility model.

[0035] Example 1

[0036] Please refer to Figure 1 This embodiment demonstrates a white-text liquid crystal writing film designed to provide superior display effects and user experience. This invention proposes a liquid crystal writing film with white text display function, which comprises at least two liquid crystal layers. The design makes the written content more clearly visible against a dark background, enhancing the user experience. This design is particularly suitable for various scenarios such as education, office, and home, and has broad application potential. In this embodiment, the liquid crystal writing film includes two liquid crystal layers, and the film layer structure from top to bottom is as follows: AG layer 10, first substrate layer 11, first conductive film layer 12, first liquid crystal layer 13, second conductive film layer 14, second substrate layer 15, first adhesive layer 16, third substrate layer 17, third conductive film layer 18, second liquid crystal layer 19, fourth conductive film layer 20, fourth substrate layer 21, second adhesive layer 22, and base layer 23. When the liquid crystal layer consists of two layers, the reflectance percentage of the top liquid crystal layer ranges from 15% to 45%, while the reflectance percentage of the bottom liquid crystal layer ranges from 55% to 85%. The reflectance percentage of the liquid crystal layers within the white writing film gradually increases from the top to the bottom. In this embodiment, the reflectance percentage of the top liquid crystal layer is 45%, and the reflectance percentage of the bottom liquid crystal layer is 55%. This design not only optimizes the visual effect of writing but also improves the visibility and contrast of the handwriting. The two liquid crystal layers can reflect a variety of colors, which can be selected according to actual needs.

[0037] Furthermore, in this embodiment, the first substrate layer 11, the second substrate layer 15, and the third substrate layer 17 of the liquid crystal writing film are all made of transparent polymer material, ensuring the overall transparency and aesthetics of the writing film. The fourth substrate layer 21 can be transparent or black, selected according to actual needs to meet different usage scenarios and aesthetic requirements.

[0038] Finally, in this embodiment, the base layer 23 of the liquid crystal writing film is a rigid backplate, providing structural support and protecting the internal circuitry from external influences. The use of a rigid backplate not only enhances the stability and durability of the writing film but also effectively prevents the internal circuitry from being affected and damaged by the external environment, thus extending the product's lifespan.

[0039] For example, in liquid crystal display technology, white light can be created by combining different colors of light. This process utilizes the principle of color superposition, where different colors of light overlap to produce new colors. Here are some common color combinations and their effects:

[0040] 1. Red plus cyan equals white: When red and cyan light are superimposed, they can cover most of the color range in the color spectrum, thus producing light that is close to white. This is because the combination of red and cyan can supplement the missing parts of each other's spectrum, forming a relatively complete white light.

[0041] 2. Green plus magenta equals white: Green light and magenta light can also produce white light when superimposed. Green light mainly occupies the middle of the visible spectrum, while magenta light is biased towards both ends. When the two colors are combined, they can cover the entire visible spectrum, forming white.

[0042] 3. Blue plus yellow equals white: The combination of blue and yellow light is based on the same principle. Blue light is biased towards one end of the spectrum, while yellow light is biased towards the other end. When combined, they can cover the entire visible spectrum, thus forming white light.

[0043] 4. Orange plus light blue equals white: The combination of orange and light blue light can also produce white light. Orange light lies between red and yellow, while light blue light lies between blue and green. This combination of colors covers the entire visible spectrum from red to violet, forming white light.

[0044] 5. Yellow-green plus violet equals white: The combination of yellow-green and violet light can also produce white light. Yellow-green light lies between yellow and green, while violet light lies between red and blue. The combination of these two colors can cover the entire visible spectrum from red to blue, forming white light.

[0045] 6. Pink plus pale cyan equals white: The combination of pink and pale cyan light can also produce white light. Pink light lies between red and white, while pale cyan light lies between blue and green. The combination of these two colors can cover the entire visible spectrum from red to blue, forming white.

[0046] These color combinations are achieved through precise control of the transmittance and reflectance of the liquid crystal layers. Each liquid crystal layer can independently adjust its color output, thus achieving different color superposition effects. For example, by adjusting the first liquid crystal layer to red light and the second liquid crystal layer to cyan light, white text can be produced by superimposing the two layers. This design not only improves the display effect but also increases the flexibility and versatility of the display.

[0047] The white-text liquid crystal writing film of this embodiment has several technical advantages. First, the white text design makes the written content more clearly visible against a dark background, improving the user experience. Second, the multi-layer structure design not only ensures the strength and durability of the writing film but also enables precise control and management of light, achieving excellent display effects. Finally, the use of a microprocessor improves the system's intelligence level, making operation simpler and faster. In summary, the white-text liquid crystal writing film provided in this embodiment is suitable for various application scenarios and has broad application prospects.

[0048] Furthermore, this utility model also proposes a liquid crystal blackboard, wherein the liquid crystal blackboard is equipped with a pen color changing device. This pen color changing device is electrically connected to the control circuit, and the desired pen color can be easily changed through the pen color changing device.

[0049] In addition, the LCD blackboard also includes an erasure position positioning device. This erasure position positioning device is also electrically connected to the control circuit, and can accurately locate and erase the position of the writing to be erased.

[0050] The LCD blackboard also includes a handwriting storage unit and a communication unit for transmitting signals to the outside.

[0051] Wherein: the handwriting storage unit is used to record the content written by the user on the LCD blackboard, including information such as the color, shape, position and timestamp of the handwriting, so as to view or restore it later; the communication unit supports wireless communication protocols, enabling the LCD blackboard to exchange data with other smart devices;

[0052] The LCD blackboard can receive signals or instructions from external devices through the communication unit.

[0053] The communication unit can export the data stored in the handwriting storage unit to an external storage medium or a cloud server to achieve data backup and sharing.

[0054] The communication unit also enables the LCD blackboard to have remote control functionality, allowing users to operate and manage the blackboard from different locations via a dedicated application.

[0055] The communication unit supports real-time synchronization to ensure information consistency between multiple LCD blackboards or between the LCD blackboard and mobile devices.

[0056] Example 2

[0057] Please refer to Figure 2This embodiment proposes a liquid crystal writing film for white writing and a liquid crystal blackboard using the liquid crystal writing film. The liquid crystal writing film for white writing includes three liquid crystal layers, each reflecting light of a different wavelength, namely red, green, and blue from the standard colors, arranged from top to bottom as red, green, and blue. To make the liquid crystal blackboard display white writing, when red, green, and blue light overlap, white light is produced. Therefore, when two or more liquid crystal layers reflecting different wavelengths overlap, white liquid crystal writing is created. However, simple superposition cannot ultimately produce a white light effect. Because the superposition structure of the liquid crystal layers causes differences in the intensity and degree of light reflected by each layer, and the outermost liquid crystal layer reflects more light, ultimately only the color of the outermost liquid crystal layer is displayed. The design of the liquid crystal writing film and liquid crystal blackboard proposed in this invention, by precisely adjusting the proportion of light wavelengths and brightness levels reflected by the RGB three-color liquid crystal layers, achieves that under natural light conditions, when RGB three colors are written simultaneously, the writing area displays white writing. This design not only improves the usability of the LCD blackboard, but also brings a new teaching tool to the education field.

[0058] Specifically, by adjusting the content of chiral agents in the formula, the red light reflection band is set at 660-720nm, the green light reflection band at 520-560nm, and the blue light reflection band at 430-450nm. This ensures that each color of light is accurately reflected. By adjusting the content of the adhesive system in the formula, the reflectivity percentage of the red liquid crystal layer is 40%–60%, the green liquid crystal layer at 30%–45%, and the blue liquid crystal layer at 10%–35%. This ensures that the intensity of different colors of light is moderate, neither too strong nor too weak. The three liquid crystal layers are stacked together in the order of red, green, and blue to form a complete white writing liquid crystal film. This stacked structure allows different colors of light to interfere and diffract after passing through multiple liquid crystal layers, thus producing the effect of white writing. Under natural light conditions, when the RGB colors are written simultaneously, due to the scattering and reflection of light, the different colors of light can be mixed evenly in space, forming the effect of white writing.

[0059] In summary, the design of the liquid crystal writing film and liquid crystal blackboard proposed in this application, by precisely adjusting the proportion of light wavelengths and brightness levels reflected by the RGB three-color liquid crystal layers, achieves white writing at the writing area when writing with all three colors (RGB) simultaneously under natural light conditions. This design not only improves the usability of the liquid crystal blackboard but also brings a new teaching tool to the education field.

[0060] Please refer to Figure 2 and Figure 3In this embodiment, the liquid crystal writing film for white text comprises three liquid crystal layers. From top to bottom, the film structure is as follows: second AG layer 100, fifth substrate layer 101, fifth conductive film layer 102, third liquid crystal layer 103, sixth conductive film layer 104, sixth substrate layer 105, seventh conductive film layer 106, fourth liquid crystal layer 107, eighth conductive film layer 108, seventh substrate layer 109, ninth conductive film layer 110, fifth liquid crystal layer 111, tenth conductive film layer 112, eighth substrate layer 113, third adhesive layer 114, and second base layer 115. The fifth substrate layer 101, sixth substrate layer 105, seventh substrate layer 109, and eighth substrate layer 113 are made of transparent polymer material, possessing good optical transparency and mechanical strength. These substrate layers not only ensure smooth light transmission but also provide sufficient structural stability to support the normal operation of the liquid crystal layer. The three liquid crystal layers utilize four substrate layers. Specifically, the sixth substrate layer 105 and the seventh substrate layer 109 are both coated with conductive films on both sides. Compared to traditional liquid crystal writing films, this embodiment saves two substrate layers, reducing production costs. The second AG layer 100 is an anti-glare layer used to reduce the impact of ambient light on the display effect and improve viewing comfort. This anti-glare layer reduces direct reflection by scattering incoming light, effectively reducing glare and providing users with a clear visual experience under various lighting conditions. The base layer is a rigid backplate, providing structural support and protecting the internal circuitry from external influences. The rigid backplate not only enhances the structural integrity of the entire liquid crystal blackboard but also provides protection against external physical impacts that could damage the internal circuitry.

[0061] Furthermore, in this embodiment, each of the three liquid crystal layers has an independent control circuit. The fifth conductive film layer 102, the sixth conductive film layer 104, the seventh conductive film layer 106, the eighth conductive film layer 108, the ninth conductive film layer 110, and the tenth conductive film layer 112 are each divided into multiple conductive regions, and the conductive regions are controlled by the control circuit. Each of the three liquid crystal layers has an independent control circuit, enabling precise control of each liquid crystal layer. The on / off state of each conductive region is relatively independent, and the circuits between them are not connected. This ensures that different colors of light can be accurately reflected during writing to form the desired color effect. At the same time, this design also avoids problems such as short circuits caused by interconnected circuits, improving the safety and stability of the liquid crystal blackboard. The fifth conductive film layer 102, the sixth conductive film layer 104, the seventh conductive film layer 106, the eighth conductive film layer 108, the ninth conductive film layer 110, and the tenth conductive film layer 112 are each divided into multiple conductive regions, and the on / off state of each conductive region is relatively independent, and the circuits between them are not connected. The conductive areas of the upper and lower film layers are arranged in a crisscross pattern in space, working in conjunction with the positioning device to enable the blackboard to perform localized erasure. This design allows for precise erasure of specific areas, improving teaching efficiency and flexibility.

[0062] Furthermore, the control circuit is a microprocessor control unit, which uses software programming to achieve precise control of each conductive area in order to adjust the transmittance and reflectance of different liquid crystal layers.

[0063] This invention also proposes a liquid crystal blackboard, which includes a handwriting color switching device. This device is electrically connected to a control circuit, allowing for easy switching of the desired handwriting color. When switching to a color other than white, simply control the on / off state of each liquid crystal layer. For example, to achieve red handwriting, the green and blue liquid crystal layers are locked, resulting in red handwriting. To achieve yellow handwriting, the blue layer is turned off, and the red and green layers are turned on, resulting in yellow. Because each liquid crystal layer undergoes reflection wavelength and brightness adjustment, the resulting color is determined by multiple layers, not just the surface color. Similarly, the following colors can be obtained: red, green, blue, cyan, yellow, and magenta. Furthermore, the liquid crystal blackboard includes an erasure position positioning device. This device is also electrically connected to the control circuit, allowing for accurate positioning and erasure of the desired handwriting position. This utility model's LCD blackboard cleverly integrates a handwriting color changing device and an erasing position positioning device. These two devices are electrically connected through a precise control circuit, jointly providing users with an unprecedented writing and erasing experience. When a user wants to change the handwriting color, they simply operate the color changing device, which immediately sends a command to the control circuit. Upon receiving these commands, the control circuit quickly adjusts the brightness ratio of the RGB light source in the LCD layer, ensuring that the newly written handwriting is presented in the user-selected color. The entire process is smooth and instantaneous, greatly enriching the color expressiveness of handwriting.

[0064] Meanwhile, the LCD blackboard is also equipped with a high-precision erasing position positioning device. This device incorporates advanced sensor technology to capture the user's erasing actions on the LCD blackboard in real time and convert these actions into precise position information. This information is then transmitted to the control circuit, which calculates the specific area to be erased and instructs the LCD layer to adjust the transmittance and reflectivity of that area, causing the writing to gradually disappear, achieving localized erasure. This design not only improves the accuracy and efficiency of erasing but also effectively avoids the dust pollution generated during traditional blackboard erasing, creating a cleaner, healthier, and more efficient learning environment for users.

[0065] This utility model's LCD blackboard not only possesses advanced functions such as handwriting color changing and erasing positioning, but also integrates a handwriting storage unit and a communication unit, providing users with a more comprehensive and convenient user experience. The handwriting storage unit, as the memory center of the LCD blackboard, can record in detail every handwriting the user makes on the blackboard, including key information such as color, shape, position, and timestamp. This data is securely stored, allowing users to easily review or restore previous writing content when needed.

[0066] The communication unit gives the LCD blackboard the ability to connect with the outside world. It supports multiple wireless communication protocols, allowing the LCD blackboard to easily connect to other smart devices, such as smartphones, tablets, or computers. Through the communication unit, the LCD blackboard can receive signals or commands from these external devices, enabling remote control and operation. For example, users can write, erase, or perform other management operations on the blackboard from different locations using a dedicated application, greatly improving the flexibility and convenience of use.

[0067] Furthermore, the communication unit also plays a crucial role in data exchange. It can export data stored in the handwriting storage unit to external storage media or cloud servers, enabling data backup and sharing. This means users can not only save important handwritten content but also easily share it with others or synchronize this data across different devices. Simultaneously, the real-time synchronization function supported by the communication unit ensures information consistency between multiple LCD blackboards or between the LCD blackboard and mobile devices, providing a consistent user experience regardless of where the user operates the device.

[0068] It should be noted that the technical solutions of the various embodiments of this utility model can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0069] The above description is only a part or preferred embodiment of this utility model. Neither the text nor the drawings should limit the scope of protection of this utility model. All equivalent structural transformations made using the content of this utility model specification and drawings under the overall concept of this utility model, or direct / indirect applications in other related technical fields, are included within the scope of protection of this utility model.

Claims

1. A liquid crystal writing film for white lettering, characterized in that, The liquid crystal writing film with white lettering includes at least two liquid crystal layers, and the writing on the liquid crystal writing film with white lettering is white. The wavelength distribution range of the liquid crystal writing film for white characters is 400nm-700nm.

2. The liquid crystal writing film of white ink according to claim 1, characterized by, The reflectivity of the liquid crystal layer within the liquid crystal writing film for white characters gradually increases from the surface layer to the bottom layer.

3. The liquid crystal writing film for white lettering according to claim 1, characterized in that, The white-text liquid crystal writing film comprises two liquid crystal layers, with the surface liquid crystal layer having a reflectance percentage of 15% to 45% and the bottom liquid crystal layer having a reflectance percentage of 55% to 85%.

4. The liquid crystal writing film of white ink according to claim 1, characterized by, The white-text liquid crystal writing film includes two liquid crystal layers. The film structure from top to bottom is as follows: AG layer, first substrate layer, first conductive film layer, first liquid crystal layer, second conductive film layer, second substrate layer, first adhesive layer, third substrate layer, third conductive film layer, second liquid crystal layer, fourth conductive film layer, fourth substrate layer, second adhesive layer, and base layer.

5. The liquid crystal writing film of white ink according to claim 4, characterized in that, The two liquid crystal layers reflect colors in combinations such as red and cyan, green and magenta, blue and yellow, orange and light blue, yellow-green and purple, and pink and light cyan.

6. The liquid crystal writing film for white lettering according to claim 4, characterized in that, Both liquid crystal layers are equipped with independent control circuits. The first conductive film layer, the second conductive film layer, the third conductive film layer, and the fourth conductive film layer are respectively divided into multiple conductive regions, and the conductive regions are controlled by the control circuits.

7. The liquid crystal writing film for white lettering according to claim 6, characterized in that, The control circuit is a microprocessor control unit that uses software programming to precisely control each conductive area in order to adjust the transmittance and reflectance of different liquid crystal layers.

8. The liquid crystal writing film for white lettering according to claim 4, characterized in that, The first substrate layer, the second substrate layer, and the third substrate layer are made of transparent polymer material, and the fourth substrate layer may be transparent or black.

9. A liquid crystal blackboard, characterized in that, The liquid crystal blackboard includes a liquid crystal writing film with white characters as described in any one of claims 1-7; The LCD blackboard is equipped with a handwriting color changing device, which is electrically connected to the control circuit. The handwriting color changing device is used to change the desired handwriting color.

10. The liquid crystal blackboard according to claim 9, characterized in that, The LCD blackboard also includes an erasure position positioning device, which is electrically connected to the control circuit and can determine the position of the writing to be erased.

11. The liquid crystal blackboard according to claim 10, characterized in that, The LCD blackboard also includes a handwriting storage unit and a communication unit for transmitting signals to the outside. Wherein: the handwriting storage unit is used to record the content written by the user on the LCD blackboard, including the color, shape, position and timestamp information of the handwriting, so as to view or restore it later; the communication unit supports wireless communication protocols, enabling the LCD blackboard to exchange data with other smart devices; The LCD blackboard can receive signals or instructions from external devices through the communication unit. The communication unit can export the data stored in the handwriting storage unit to an external storage medium or a cloud server to achieve data backup and sharing. The communication unit also enables the LCD blackboard to have remote control functionality, allowing users to operate and manage the blackboard from different locations via a dedicated application. The communication unit supports real-time synchronization to ensure information consistency between multiple LCD blackboards or between the LCD blackboard and mobile devices.

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