Light-driven dynamic imaging device based on ultrathin paper stack and method thereof

Abstract

The invention discloses a light-driven dynamic imaging device based on ultra-thin paper stacking and a method thereof, and relates to the technical field of dynamic display, in particular to the light-driven dynamic imaging device based on the ultra-thin paper stacking and the method thereof, the light-driven dynamic imaging device based on the ultra-thin paper stacking comprises an ultra-thin functional paper layer formed by vertically stacking 20-200 layers of ultra-thin functional paper, and the thickness of a single layer of paper is 8-25 microns. The end face of part of the ultrathin functional paper is coated with a composite functional material which comprises a reversible photochromic material, and the reversible photochromic material can be turned into an opaque state under illumination to form a reversible covering layer, so that lower-layer image residues are dynamically covered, and image crosstalk is prevented. And the transparent state is recovered under the dark condition to realize image clearing. The method includes patterning a coating material on paper by a printing process and stacking to form a multi-layer structure. The invention further relates to auxiliary structures such as a photothermal conversion layer and a nano-porous isolating membrane so as to accelerate resetting and prevent interlayer adhesion. The device realizes light-driven dynamic imaging, and has the advantages of reversibility, high resolution and low crosstalk.

Description

Technical Field

[0001] This invention relates to the field of dynamic display technology, specifically to a light-driven dynamic imaging device and method based on ultrathin paper stacking. Background Technology

[0002] Dynamic display technology is widely used in packaging printing, educational aids, anti-counterfeiting labels, and interactive media, enhancing the vividness and interactivity of information delivery. Currently, mainstream dynamic display devices (such as electronic displays or electrochromic devices) typically rely on external power supplies, limiting their application in passive or low-power scenarios and potentially leading to complex wiring, high energy consumption, and poor environmental adaptability. In recent years, light-driven dynamic display technology has attracted attention due to its use of ambient light as an energy source; however, existing solutions still face challenges such as limited dynamic effects, low reset efficiency, inability to repeat playback, and difficulty in achieving color display. Summary of the Invention

[0003] The purpose of this invention is to provide a light-driven dynamic imaging device and method based on ultra-thin paper stacking. The device uses light energy as the driving force, the precise stacking of ultra-thin functional paper and the intelligent response of photochromic material to realize pure light-controlled dynamic image display without complex circuits. The function of the reversible photochromic material is to form a reversible "intelligent covering layer" between adjacent paper layers.

[0004] To achieve the above objectives, this invention provides a light-driven dynamic imaging device and method based on ultrathin paper stacking. Its innovation lies in the vertical stacking of 20-200 layers of ultrathin functional paper, each only 8-25 micrometers thick, which constitutes a precise layered structure. The thinness of each single paper layer ensures that the overall device maintains a relatively slim profile while possessing a sufficient number of information layers (for imaging), which is crucial for achieving a portable and compact device. More importantly, by incorporating a composite functional material containing reversible photochromic material on the end faces of some paper layers, the device achieves light-driven dynamic imaging and erasing. Its working principle is based on intelligent response to ambient light: when exposed to light, the reversible photochromic material undergoes a chemical reaction, changing from a transparent state to an opaque state, much like instantly pulling a light-blocking curtain between adjacent paper layers. This effectively covers the old image residue on the lower layer, preventing visual crosstalk and thus displaying a clear new image. When in a dark environment, the material automatically returns to transparency, allowing the lower layer image to appear or be rewritten by a new lighting pattern. This "light-controlled shutter" mechanism avoids the complex circuitry and continuous power supply required by traditional electronic displays, providing a completely new path for developing low-power, paper-like dynamic imaging technology.

[0005] Furthermore, the scope is narrowed down to three high-performance materials: spiropyran compounds, diarylethylene compounds, and silver halides. This limitation is crucial because it ensures the feasibility and high performance of the device in practical applications. Spiropyran compounds have the advantages of fast color-changing response, relatively high fatigue resistance, and good solubility in organic solvents, making them easy to formulate into printing inks. Diarylethylene compounds, especially certain derivatives, have excellent thermal stability and fatigue resistance. Their color-changing reaction is a reversible ring-opening / ring-closing reaction based on molecular configuration, enabling rapid and reversible switching under specific wavelengths of light, making them ideal for scenarios requiring long-term, repetitive use. Silver halides, on the other hand, are the core photosensitive material in traditional photographic film, and their photochemical properties have been thoroughly studied, exhibiting extremely high photosensitivity and imaging resolution.

[0006] Furthermore, the composite functional material is not uniformly coated across the entire paper layer, but rather applied in "pre-designed patterned areas." This means that the reversible photochromic material can be precisely printed in specific locations, such as forming text, lines, QR codes, or more complex graphic areas. In addition, different areas can be coated with materials that have different color rendering properties; for example, some areas turn blue under ultraviolet light, while others turn red under visible light. This technology greatly expands the device's imaging capabilities, upgrading it from a single, uniform color change to displaying complex, dynamic images with multiple colors and patterns. Achieving this patterned coating requires high-precision printing technology, reflecting the precision of the device's manufacturing process.

[0007] Furthermore, this functional layer is typically composed of materials capable of efficiently converting specific wavelengths of light energy (such as infrared light) into heat energy, such as carbon nanotubes, graphene, or certain metal oxide nanoparticles. It can be placed on the side of the paper stack or between layers. When rapid image erasure is required, in addition to placing the device in a light-protected environment, a beam of infrared light that will not trigger a color-changing reaction (or has minimal impact) can be used to irradiate the device. The photothermal conversion layer absorbs the infrared light and rapidly generates heat, slightly raising the local temperature of the paper stack. It is well known that the reset process of many photochromic materials is thermally driven; heating can significantly accelerate the speed at which their molecular structure recovers from a metastable state to the ground state, thus achieving image erasure in seconds or even faster. This design cleverly separates the different uses of light energy: visible / ultraviolet light is used for "writing" images, and infrared light is used for "erasing" images, greatly improving the ease of use and response efficiency of the device.

[0008] Furthermore, when ultrathin papers are stacked together, interlayer adhesion can easily occur under changes in humidity, temperature, or slight pressure, leading to the failure of the entire device. The introduction of a nanoporous insulating membrane, acting like an extremely thin and robust "scaffolding," is placed on the inner end face of the paper layers, its core function being physical isolation. It is typically made of polymers (such as polytetrafluoroethylene) or inorganic materials (such as anodized aluminum) and has a porous structure with pore sizes at the nanoscale. This structure effectively prevents direct contact and hydrogen bonding between paper fibers, avoiding adhesion, while its porous nature allows air and a small amount of moisture to pass through. This gas exchange capability is crucial for the stable operation of reversible photochromic materials, as it can promptly dissipate any gaseous byproducts that may be generated during the color-changing reaction, or balance internal and external humidity, providing a stable microenvironment for the chemical reaction, indirectly assisting the material's resetting process, and ensuring the long-term repeatability of the imaging-erasing cycle.

[0009] Furthermore, the color change is achieved through changes in the molecular structure of the material itself, rather than relying on the physical mixing or migration of dye particles. For example, under ultraviolet light irradiation, the CO bonds of spiropyran molecules undergo heterolytic cleavage, transforming the molecule from a closed-ring, colorless spirocyclic form to an open-ring, colored cyanine form. This process is accompanied by the expansion of the entire π-electron conjugated system, thereby absorbing visible light and exhibiting color. When the light is removed, because the open-ring form is thermodynamically unstable, the molecule spontaneously returns to the stable closed-ring, colorless form through the recombination (reset) of chemical bonds. This mechanism based on intramolecular structural changes makes the color change process very rapid, uniform, and reversible (with good fatigue resistance). It differs from materials that are irreversible or require external stimuli (such as electrolysis) to reset, ensuring that the device can achieve truly "dynamic" and "repeatable" imaging, which is one of the core advantages of this invention.

[0010] Furthermore, under repeated light exposure cycles, especially in the presence of oxygen and moisture, the molecules of reversible photochromic materials may undergo irreversible side reactions, such as degradation due to attack by photoactive species (e.g., singlet oxygen or free radicals), leading to a gradual weakening of their color-changing ability, i.e., "aging." Adding functional additives to composite functional materials serves to capture these harmful free radical molecules. These additives are typically highly efficient antioxidants or light stabilizers that preferentially react with free radicals, thus "sacrificing" themselves to protect the main structure of the photochromic molecules from damage. This is equivalent to putting a "protective suit" on the photochromic material, significantly delaying the aging process caused by photo-oxidation, allowing the entire device to withstand thousands or even more imaging-erasing cycles without significant performance degradation. This is crucial for ensuring the reliability of the product during long-term use.

[0011] Further, the first step is to provide ultra-thin functional paper that meets thickness specifications (8-25 micrometers). This paper may undergo special treatment to achieve high strength, smoothness, and chemical inertness to withstand subsequent processes. The second step is a critical process: precisely coating a composite functional material containing reversible photochromic materials onto designated ends of a portion of the paper using a printing process. This requires the printing process to have high-precision positioning capabilities to ensure consistent and controllable coating position and thickness. The third step is stacking and alignment, which is the core of assembly. Dozens to hundreds of processed sheets of paper need to be stacked layer by layer in a predetermined order and with strict positioning (possibly through optical or mechanical positioning systems) to form a whole. The precision of each step directly affects the clarity and accuracy of the final image. The entire process embodies a systematic manufacturing philosophy from material preparation and functionalization to precision assembly.

[0012] Furthermore, gravure printing is a highly suitable technology for this invention. Its printing plate surface is engraved with recessed ink-receiving cavities, allowing for precise control of the amount of ink transferred onto the paper, resulting in a coating with uniform thickness and clear edges. The term "micro-area positioning" refers to the technology's ability to precisely coat extremely small areas (such as micrometer-level lines or dot matrices), which is crucial for achieving the complex patterned imaging described in claim 3. The "multicolor coating" capability allows for the sequential and precise coating of multiple different colors of reversible photochromic inks onto different areas of the same sheet of paper, thereby achieving multi-color dynamic display. This high-precision manufacturing method ensures that functional materials are precisely placed in preset positions, providing a technical guarantee for the final device to achieve high-quality, high-resolution dynamic imaging, and also demonstrating the innovation of this patent in manufacturing processes.

[0013] Furthermore, the method of using the dynamic imaging device, i.e., its working cycle, is as follows: The first step is "dynamic development": The user exposes the device to light of a specific wavelength and intensity (such as sunlight, ultraviolet light, or a projector light source). The light penetrates the transparent paper layer and is absorbed by the composite functional material in specific areas, triggering its photochromic reaction, changing it from a colorless transparent state to an opaque colored state. Because the color-changing area covers the underlying layer, an image corresponding to the illuminated pattern is visually "displayed." The second step is "image erasure": When it is necessary to replace or eliminate the image, the user simply moves the device to a light-protected environment (such as placing it in a dark box or covering it). In the dark, the photochromic material loses its energy input, and its unstable colored molecules spontaneously recover to a stable transparent ground state through a thermal relaxation process. The image gradually fades until it disappears completely, preparing for the next imaging. This process does not consume electrical energy for erasure, achieving true light-driven operation and low power consumption.

[0014] This invention provides a light-driven dynamic imaging device and method based on ultrathin paper stacking, which has the following beneficial effects:

[0015] 1. This device utilizes the property of reversible photochromic materials to become opaque under light, forming a dynamic, reversible masking layer between adjacent paper layers. This design effectively blocks light interference from the upper image to the lower layer, significantly reducing image crosstalk caused by light penetration. Compared to traditional anti-crosstalk technologies that rely on physical barriers or complex electronic controls, this light-driven masking mechanism is more direct and efficient. It ensures that the image presented by each layer has a high degree of independence and clarity, resulting in rich details and distinct layers in the final superimposed stereoscopic or dynamic image, greatly improving image quality and visual experience. This active anti-crosstalk based on the inherent properties of the material provides a reliable solution for multi-layer displays of high-density information.

[0016] 2. By coating the end face of ultra-thin functional paper with composite functional materials in a preset pattern, and by using materials with different color rendering properties in different areas, this device can achieve complex multi-color dynamic imaging effects. This method provides a high degree of design freedom in the imaging process, allowing creators to precisely plan the color distribution and variation patterns in advance. When exposed to light, the materials in different areas display rich colors according to their characteristics, together forming a complete color pattern. This patterned, multi-color development capability makes the device suitable not only for simple image display, but also for applications such as high-end anti-counterfeiting, artistic creation, and complex visual identification, demonstrating powerful expressiveness and application potential.

[0017] 3. The integrated photothermal conversion functional layer provides an effective acceleration pathway for the resetting process of composite functional materials from a chromatic state to a transparent state. This functional layer can convert absorbed light energy into heat energy, using heat to promote the rapid recovery of the molecular structure of the photochromic material from the excited state to the stable ground state. This mechanism significantly shortens the waiting time required for image clearing, improving the overall efficiency and response speed of the device. Compared with the slow thermal relaxation process relying solely on natural light-shielding environments, this proactive thermal management strategy allows the device to prepare for the next imaging more quickly, making it particularly suitable for dynamic displays or information refresh scenarios that require frequent updates to the displayed content, thus enhancing the device's practicality and reusability.

[0018] 4. The nanoporous isolation membrane placed at the inner end of the ultrathin functional paper layer offers dual benefits. Firstly, it physically prevents the extremely thin paper layers from sticking together under stacking pressure, ensuring the independence and stability of the multilayer structure—the foundation for clear, layered imaging. Secondly, this isolation membrane allows for micro-exchange of gas between layers, providing a suitable microenvironment for some reversible photochromic materials that may be sensitive to oxygen or water vapor in the environment, thus helping to regulate their color-changing and resetting kinetics. This ingenious structural design maintains physical isolation while also considering the chemical environment required for material function, thereby ensuring the reliability and durability of the imaging device during long-term use and extending its service life.

[0019] 5. The overall structure and material selection of this imaging device tend towards simplified and low-cost manufacturing. Its core relies on ultra-thin paper stacking and printing coating processes, both mature and easily scalable technologies. For example, gravure printing enables micro-area positioning and color matching, ensuring the accuracy and consistency of the pattern. This manufacturing strategy avoids reliance on expensive, complex precision optical components or electronic drive systems, effectively controlling the device's production costs. Therefore, this technical solution is feasible for large-scale production and is expected to serve as an economical and environmentally friendly dynamic imaging or display medium for a wide range of cost-sensitive applications, such as disposable or reusable product packaging, general anti-counterfeiting labels, and simple information displays. Attached Figure Description

[0020] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0022] Figure 2 This is a graph showing the transmittance calculation model of the present invention.

[0023] Figure 3 This is a chromaticity change spectrum during the reset process of the present invention;

[0024] Figure 4 This is a schematic diagram of color dynamic imaging according to the present invention. Detailed Implementation

[0025] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses consistent with some aspects of this disclosure as detailed in the appended claims.

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0027] Example 1: Basic device structure based on 50 layers of ultra-thin functional paper stacking

[0028] This embodiment specifically illustrates the basic structure of a light-driven dynamic imaging device based on ultrathin paper stacking. The core of the device is an ultrathin functional paper layer 1, formed by vertically stacking 50 layers of ultrathin functional paper. Each layer of ultrathin functional paper is 15 micrometers thick and made of high-transmittance cellulose paper material, with a visible light transmittance exceeding 92%, ensuring clear transmission of the underlying image. The surface of each paper layer is smoothed to reduce light scattering. A composite functional material 2 is coated on the end faces of some ultrathin functional paper layers. This material is mainly composed of spiropyran-based reversible photochromic compounds. Under ultraviolet light irradiation, the spiropyran compounds undergo a molecular cyclization reaction, changing from a colorless and transparent state to a blue opaque state, thereby forming a dynamic masking layer between adjacent paper layers. The coated area uses a pre-designed grid pattern with a grid line width of 100 micrometers and a spacing of 500 micrometers to achieve a uniform masking effect. When the device is exposed to light, the composite functional material coated on the end face quickly becomes opaque, blocking residual light signals from the underlying image and preventing crosstalk. In a light-protected environment, the spiropyran compound automatically resets to a transparent state through a thermally driven reverse reaction, restoring the paper's original light transmittance. Furthermore, a nanoporous isolation membrane 4, made of polytetrafluoroethylene (PTFE), is located at the inner end of the ultra-thin functional paper layer. This membrane is 5 micrometers thick and has a pore size of 50-100 nanometers. The isolation membrane prevents the 50 layers of paper from sticking together under stacking pressure, while its porous structure allows air circulation, regulating the interlayer microenvironment and accelerating the reset process of the composite functional material in the dark. The entire device measures 10 cm × 10 cm × 1.5 mm, making it suitable for portable dynamic display devices. This embodiment achieves high-contrast dynamic imaging through precise control of paper thickness and coating pattern, and operates solely based on light drive without requiring an external power supply.

[0029] Example 2: Method for manufacturing an apparatus using gravure printing technology

[0030] This embodiment details a method for manufacturing a light-driven dynamic imaging device based on ultrathin paper stacking. First, 80 sheets of ultrathin functional paper are prepared, each with a single-layer thickness of 12 micrometers. The paper material is modified plant fiber, with a tensile strength of not less than 5 MPa to ensure mechanical stability during stacking. Next, a composite functional material 2 is coated onto the end faces of 20 sheets of ultrathin functional paper using gravure printing. Gravure printing uses a stainless steel anilox roller with micrometer-level pit patterns engraved on the roller surface, corresponding to the desired coating areas. The composite functional material is based on a diarylethylene-based reversible photochromic compound, mixed with a UV-curable resin as a carrier to ensure coating adhesion and durability. During coating, the printing press operates at a speed of 0.1 meters per minute, achieving a coating accuracy of ±10 micrometers, enabling micro-area positioning and color matching. Different areas can be coated with materials with different color rendering properties; for example, diarylethylene can be used in some areas, while silver halide can be used in others to create a multi-color dynamic effect. After coating, the paper is cured under nitrogen protection with a UV lamp for 10 seconds to ensure strong coating adhesion. Subsequently, a stacking process is performed: coated and uncoated sheets of paper are alternately arranged, and an optical alignment instrument is used to ensure that the edges of each layer are aligned, vertically stacking them into an 80-layer structure. During stacking, a nanoporous isolation membrane 4 is inserted between every 10 layers of paper. The isolation membrane is a polyvinyl alcohol porous membrane with a pore size of approximately 80 nanometers and a thickness of 3 micrometers; its hydrophilic properties help regulate interlayer humidity. After stacking, the device is cold-pressed at 0.5 MPa for 10 minutes to form a monolithic block structure. Finally, a photothermal conversion functional layer 3, made of graphene composite material and 20 micrometers thick, is integrated into the side of the device and bonded to the side of the paper stack by hot pressing. The photothermal conversion layer can absorb infrared light and convert it into heat energy, providing uniform heating when protected from light and accelerating the resetting of diarylethylene compounds. This method achieves large-scale, highly consistent device production through precision printing and stacking technology.

[0031] Example 3: Method and process of using dynamic imaging operation

[0032] This embodiment focuses on describing the usage of the light-driven dynamic imaging device. The device is composed of 100 layers of ultra-thin functional paper, each layer being 10 micrometers thick, for a total thickness of approximately 1 millimeter. Composite functional material 2 is coated on the end faces of 30 layers of paper. The material composition is a reversible photochromic silver halide system, characterized by its fast response speed and high cycle life. Before use, the device is in an initially transparent state, with all paper layers having uniform light transmittance. The dynamic imaging process begins with light triggering: the device is placed under a 2000 lux ultraviolet light source for 3 seconds. During illumination, the silver halide-coated end faces undergo a photolysis reaction, generating metallic silver particles, causing the coating to change from transparent to a dark brown opaque state, thus dynamically masking the underlying image. For example, if the underlying layer contains a static pattern, the masking layer can selectively block certain areas, creating a dynamic contrast effect. After development, the device remains stable under indoor light, and the image can be maintained for several minutes. To clear the image, the device is moved to a dark environment or placed in a constant temperature environment at 40°C. In the absence of light, silver halide gradually resets through a thermal recombination reaction, with a transparent state recovery time of approximately 20 seconds; with the aid of heating, this can be shortened to 5 seconds. During this process, the nanoporous isolation membrane 4 plays a crucial role: its porous structure promotes oxygen diffusion, helps balance the redox reaction of silver halide, and prevents residual images. Furthermore, the photothermal conversion layer 3 can optionally be integrated into the side of the device; when irradiated with an infrared lamp, this layer heats up to 45°C, further accelerating the reset process. This method requires no electronic controls; repeatable imaging is achieved simply by switching between light and dark, making it suitable for safety signs or dynamic art displays. After each use, the device automatically resets to ensure no crosstalk during the next imaging session.

[0033] Example 4: Device variant with integrated photothermal conversion functional layer

[0034] This embodiment relates to a variant of the device integrating a photothermal conversion functional layer 3, designed to improve reset efficiency. The main body of the device consists of 120 layers of ultra-thin functional paper vertically stacked, each layer being 20 micrometers thick. The paper material is a special paper doped with silica nanoparticles to enhance thermal stability. A composite functional material 2 is coated on the end faces of 40 layers of paper, its main component being spiropyran compounds, with a photoresponse band ranging from ultraviolet to blue light, and a blue opaque state after color change. The photothermal conversion layer 3 is disposed on the side of the ultra-thin functional paper layers, made of carbon nanotubes and a polymer matrix, with a thickness of 30 micrometers and a thermal conductivity as high as 200 W / m·K. This layer is bonded to the four sides of the paper stack using a hot-pressing process, forming an enclosing structure. When the device is illuminated for imaging, the composite functional material changes color to cover the lower layer; during the reset phase, the photothermal conversion layer plays an important role: if an infrared light source is used to illuminate the sides, the CNT layer efficiently absorbs light and generates heat, causing the temperature of the paper stack to rise uniformly to 50°C. Heat is conducted internally, accelerating the thermal fading reaction of spiropyran molecules, reducing the reset time from 60 seconds under natural light-shielded conditions to less than 10 seconds. Simultaneously, a nanoporous insulating membrane 4, made of polyimide porous membrane with a pore size of 100 nanometers and a high-temperature resistance of up to 200℃, is placed between the layers. This prevents interlayer adhesion and regulates heat distribution through gas exchange. Functional additives, such as hindered amine light stabilizers, are also added to the composite functional material 2 to capture free radicals generated by ultraviolet light and delay the aging of spiropyran. Tests show that the color-changing contrast of this variant device remains above 90% after 1000 light-driven cycles. This design is particularly suitable for high-temperature environments or scenarios requiring rapid reset, such as industrial process monitoring or automotive head-up displays.

[0035] Example 5: Application of Patterned Coating for Multicolor Dynamic Imaging

[0036] This embodiment demonstrates a specific application of multicolor dynamic imaging achieved through patterned coating of composite functional material 2. The device consists of 200 layers of ultra-thin functional paper stacked together, with a single layer thickness of 8 micrometers, designed for minimum thickness to maximize resolution. The paper is optical-grade cellulose paper with a light transmittance of 95%. Composite functional material 2 is coated onto the end faces of 50 layers of paper in pre-designed patterned areas. The coating process uses high-precision gravure printing, with a color registration error of less than 5 micrometers. The pattern design includes geometric shapes such as circles and squares, and text such as "ON / OFF" markings. Different areas are coated with different reversible photochromic materials: diarylethylene compounds are used for circular areas, spiropyran compounds for square areas, and silver halides for text areas. During coating, the material is mixed with UV-curable acrylic resin to ensure clear pattern edges. Under light-driven conditions, the device is exposed to a broadband light source, and each area synchronously develops color according to the material properties, forming a multicolor dynamic image. For example, in security and anti-counterfeiting applications, light exposure can trigger the emergence of hidden patterns. After light exposure, all materials automatically reset at room temperature, and the image is completely cleared within 30 seconds. Inside the device, the nanoporous isolation membrane 4 is a polypropylene porous membrane with a pore size of 50 nanometers and a thickness of 2 micrometers. Its hydrophobic properties prevent moisture from affecting the color-changing performance. Additionally, a photothermal conversion layer 3, optionally installed between the layers, is made of carbon black composite material and has a thickness of 10 micrometers. It is locally heated under infrared light to achieve selective pattern resetting. This embodiment expands the dynamic display capabilities of the device through micro-area coating and material combination, making it suitable for high-end packaging, art installations, or interactive labels. Furthermore, all processes are light-controlled, with no energy consumption.

[0037] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A light-driven dynamic imaging device and method based on ultrathin paper stacking, comprising an ultrathin functional paper layer (1), characterized in that: The ultra-thin functional paper layer (1) is composed of 20-200 layers of ultra-thin functional paper stacked vertically. The thickness of a single layer of ultra-thin functional paper is 8-25 micrometers. Some of the ends of the ultra-thin functional paper layer (1) are provided with composite functional material (2). The composite functional material (2) includes a reversible photochromic material, which is used to form a reversible cover layer between adjacent layers. Under light, the reversible cover layer becomes opaque to dynamically cover the image residue of the lower layer. Under light avoidance, it returns to a transparent state, thereby preventing image crosstalk.

2. The light-driven dynamic imaging device and method based on ultrathin paper stacking according to claim 1, characterized in that: The reversible photochromic material in the composite functional material (2) is selected from the group consisting of spiropyran compounds, diarylethylene compounds and silver halides.

3. The light-driven dynamic imaging device and method based on ultrathin paper stacking according to claim 1, characterized in that: The composite functional material (2) is coated on the end face of the ultra-thin functional paper layer (1) with a pre-designed patterned area, and the composite functional material (2) coated in different areas has different color rendering characteristics.

4. The light-driven dynamic imaging device and method based on ultrathin paper stacking according to claim 1, characterized in that: The device also includes a photothermal conversion functional layer (3), which is disposed on the side or between layers of the ultrathin functional paper layer (1) to absorb light energy and convert it into heat energy to accelerate the resetting process of the composite functional material (2).

5. The light-driven dynamic imaging device and method based on ultrathin paper stacking according to claim 1, characterized in that: The inner end of the ultrathin functional paper layer (1) is provided with a nanoporous isolation membrane (4). The nanoporous isolation membrane (4) is used to prevent interlayer adhesion of the ultrathin functional paper layer (1) and at the same time allow gas exchange to regulate the resetting process of the composite functional material (2).

6. A light-driven dynamic imaging device and method based on ultrathin paper stacking according to claim 2 or 3, characterized in that: The composite functional material (2) changes color through changes in molecular structure under light response, and automatically resets to its initial state when there is no light.

7. The light-driven dynamic imaging device and method based on ultrathin paper stacking according to claim 2, characterized in that: The composite functional material (2) also includes functional additives, which are used to capture free radical molecules to delay material aging.

8. The light-driven dynamic imaging device and method based on ultrathin paper stacking according to claim 1, characterized in that: Includes the following steps: Multiple sheets of ultra-thin functional paper are available, with a single-layer thickness of 8-25 microns; Composite functional material (2) is coated on the end face of some ultra-thin functional paper by printing process. The composite functional material (2) includes reversible photochromic material. The coated ultrathin functional paper is stacked and aligned to form an ultrathin functional paper layer consisting of 20-200 vertically stacked layers (1).

9. The light-driven dynamic imaging device and method based on ultrathin paper stacking according to claim 8, characterized in that: The printing process is gravure printing, and it can perform micro-area positioning and color coating to achieve precise coating of patterned areas.

10. The light-driven dynamic imaging device and method based on ultrathin paper stacking according to claim 2, characterized in that: Includes the following steps: The device is exposed to light to trigger the color development reaction of the composite functional material (2) to achieve dynamic development; The device is placed in a light-proof environment or a specific temperature environment to reset the composite functional material (2) to a transparent state in order to achieve image clearing.

Images