Micro-nano structure filling method based on dual-wavelength response microcapsule

Abstract

The application discloses a micro-nano structure filling color method based on double-wavelength response microcapsules, and aims at the problems of traditional microstructure ink scraping filling color process being complicated, yield being low, color being single, and background color of a photochromic system being easily affected by environmental light. A double-wavelength response microcapsule preparation filling slurry containing leuco dye, photoacid generator and photoalkaline generator is adopted, after substrate coating and pre-curing, a first waveband light source mask exposure is carried out to realize patterning color development, and then a second waveband light source full-width irradiation is carried out to make the photoacid generator in the uncolored area be irreversibly inactivated, and fixing and locking the background are completed. Finally, the optical lens layer is attached to obtain a naked-eye suspension pattern product. The application can omit the ink scraping process, support multi-color pattern preparation, and has strong weather resistance, and can be widely applied to the fields of anti-counterfeiting, decoration and display.

Description

Technical Field

[0001] This invention relates to the field of microstructure pattern preparation, specifically to a method for coloring micro-nano structures based on dual-wavelength responsive microcapsules. Background Technology

[0002] With the development of micro-nano optics technology, naked-eye levitation pattern technology has been widely used in anti-counterfeiting labels, consumer electronics appearance, and decorative displays. The core principle of naked-eye levitation patterns is the precise alignment and UV transfer of a microlens array (MLA) layer and a micropattern array (MPA) layer. Utilizing the refractive imaging effect of the microlenses, the pattern on the MPA layer presents a three-dimensional levitation visual effect detached from the substrate. Currently, the mainstream fabrication process for MPA micropattern layers is the scraping and filling method. Color ink is scraped onto the surface of a microstructure substrate with micron-level grooves, filling the grooves to form a pattern. Since ink residue is not allowed in non-pattern areas, excess ink outside the grooves must be wiped clean manually or with specialized equipment. However, this process has many shortcomings in actual production: the ink-wiping process requires high precision and relies heavily on manual operation, resulting in low production efficiency and high labor costs. Furthermore, the wiping process easily causes mechanical damage to microstructures, leading to problems such as ink residue and ink being carried out of the grooves, resulting in a low product yield. Traditional ink-scraping processes can only achieve single-color filling, making it difficult to prepare multi-color or true-color patterns in micron-level microstructures, thus limiting the visual expressiveness of the patterns. Existing photochromic filling solutions are mostly reversible systems, and non-pattern areas are easily affected by ambient light, resulting in unexpected color development. The long-term stability and weather resistance of the patterns are insufficient, making it difficult to meet the requirements of mass-produced products. Traditional processes only generate patterns and cannot achieve the concealed generation of anti-counterfeiting patterns, making imitation cost low.

[0003] Therefore, in order to solve the problems existing in the prior art, this invention proposes a micro-nano structure coloring method based on dual-wavelength response microcapsules. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a micro / nano structure coloring method based on dual-wavelength responsive microcapsules. To achieve this objective, the present invention provides the following technical solution, including: The color-changing slurry preparation step involves dispersing dual-wavelength responsive microcapsules in a matrix resin to prepare a color-changing filler slurry, wherein the microcapsules include leuco dyes, photoacid generators, and photoalkali generators. In the substrate filling and coating step, the color-changing filler slurry is attached to the substrate surface to generate a microcapsule coating covering the target area, and the microcapsule coating is pre-cured to fix the position of the microcapsules. In the pattern color development and exposure step, a first mask is set on the microcapsule coating, and selective irradiation is performed by a light source with a preset first wavelength, so that the photoacid-producing agent of the microcapsule in the light-transmitting area decomposes and releases acidic substances, triggering the ring-opening color development of the leuco dye to generate the main pattern color development area. In the global fixing and base locking step, the first mask is removed, and the substrate is fully irradiated by a light source with a preset second band, so that the photo-induced alkali-generating agent in the entire area decomposes and releases alkaline substances, neutralizes and deactivates the undecomposed photo-induced acid-generating agent in the undeveloped area, and completes the base color locking. In the curing and bonding step, the substrate with the base color locked is post-cured to stabilize the cross-linking of the matrix resin. The cured substrate pattern layer and the optical lens layer are then aligned and UV-transferred to generate a naked-eye floating pattern product.

[0005] As a further improvement of the present invention, the substrate filling and coating step includes: quantitatively guiding and distributing the flowing color-changing filler slurry onto the surface of the substrate by means of planar coating or droplet spraying; the color-changing filler slurry itself flows and merges on the substrate by its own surface tension, expanding to form a smooth liquid film that continuously covers the entire target area, and the smooth liquid film has a uniform physical thickness in the direction perpendicular to the substrate; and the smooth liquid film is pre-cured to form a microcapsule coating with a solid morphology. By employing a film-forming mechanism that combines planar liquid application with surface tension self-leveling, the physical structure directly eliminates the constraints of micro-groove boundaries that traditional microstructure filling relies on. This completely eliminates the need for physical wiping or scraping of excess paste in non-patterned areas of the substrate, simplifying the preparation process and improving efficiency. Furthermore, the microcapsule coating with a uniform physical thickness in the vertical direction ensures the uniformity of acid production and color development in the main patterned area through photochemical reactions. It also lays the physical spatial foundation for subsequent anti-counterfeiting exposure steps, such as constructing lateral spatial projection misalignment within the coating using tilted light paths and providing precise focal length matching thickness for the final optical lens layer.

[0006] As a further improvement of the present invention, an anti-counterfeiting pattern exposure step is also included. A second mask with an anti-counterfeiting pattern is set on the microcapsule coating. The second mask and the surface of the microcapsule coating maintain a preset physical suspension span. The thickness of the preset physical suspension span matches the microscopic refractive focal length of the optical lens layer. The physical suspension span serves as the physical boundary for constructing multi-view suspended optical parallax in the two-dimensional plane in the longitudinal depth space. By setting a specific physical suspension span between the second mask and the microcapsule coating, not only is direct physical contact between the mask and the microcapsule coating avoided, maintaining the surface integrity of the flat liquid film, but also a precise longitudinal geometric space is artificially reserved above the two-dimensional coating by binding the thickness of the suspension span with the refractive focal length of the final optical lens layer as a low-level parameter. This spatial layout directly provides the necessary physical conditions for generating microscopic lateral projection misalignment using tilted beams in subsequent steps. It is the structural basis for transforming the planar photochemical color development reaction into a three-dimensional parallax anti-counterfeiting effect, laying the foundation for the subsequent covert writing and multi-view decryption of the anti-counterfeiting pattern.

[0007] As a further improvement of the present invention, the anti-counterfeiting pattern exposure step further includes: guiding the light passing through the second mask through a preset tilt angle using the light source of the first band; achieving spatial projection misalignment of the light in the microcapsule coating along the lateral direction based on the physical suspension span of the second mask and the uniform physical thickness of the microcapsule coating; triggering the decomposition of photoacid-producing agents in the microcapsules outside the main pattern color area to release acidic substances; and generating an anti-counterfeiting pattern that is on the same physical reference plane as the main pattern color area and has a lateral parallax offset. By introducing a light source at a preset tilt angle and utilizing the spatial geometric projection principle of light passing through the suspended mask, the vertical physical gap is transformed into a lateral exposure displacement inside the microcapsule coating, enabling the anti-counterfeiting pattern to coexist synchronously with the main pattern on the same physical reference plane without the need for additional physical ink layers or complex overprinting processes. This lateral parallax offset causes the anti-counterfeiting graphics to be obscured by the color area of ​​the main pattern when viewed directly. At the same time, it converts the spatial misalignment into an optical phase difference, providing precise physical displacement parameters for the subsequent curing and bonding steps to perform split-view modulation through the optical lens layer and visual decryption at a specific tilt angle. This constitutes the core of the parallax anti-counterfeiting technology closed loop.

[0008] As a further improvement of the present invention, the anti-counterfeiting pattern exposure step further includes: obtaining the microscopic optical modulation period based on the physical pitch of the individual lenses of the optical lens layer; determining the upper limit of the target lateral offset of the anti-counterfeiting pattern relative to the color display area of ​​the main pattern based on the microscopic optical modulation period; using the target lateral offset as a control target; deriving and matching the geometric linkage relationship between the physical suspension span and the preset tilt angle based on the uniform physical thickness of the microcapsule coating; and increasing the light energy exposure threshold of the secondary guided irradiation by adjusting the incremental extension of the actual penetration path inside the microcapsule coating by the preset tilt angle based on the deep exponential attenuation characteristic of the microcapsule to ultraviolet light intensity, thereby compensating for the scattering attenuation loss of tilted penetration. By introducing a parallax boundary constraint mechanism based on the physical pitch of a single lens, the upper limit of the lateral offset of the anti-counterfeiting pattern is reasonably limited, avoiding visual ghosting caused by excessive misalignment spanning a single lens cycle. By establishing a geometric inversion logic for physical thickness, overhang span, and tilt angle, the light and shadow misalignment target is transformed into quantitative spatial process parameters. A dynamic optical path attenuation compensation mechanism is introduced to overcome the effects of extended tilted exposure paths and material light absorption characteristics, ensuring the integrity of the acid-producing colorimetric reaction of the microcapsules at the bottom of the coating. This series of algorithmic control mechanisms reduces the trial-and-error costs during process debugging, providing system-level parameter processing and control support for the final stable production of anti-counterfeiting products with clear parallax decryption effects.

[0009] As a further improvement of the present invention, the dual-wavelength responsive microcapsule is a core-shell isolated encapsulation structure. This structure comprises a high-transmittance polymer capsule wall and a core composite system. The high-transmittance polymer capsule wall has optical transmittance that allows light sources of the first and second wavelength bands to pass through. The core composite system comprises a triarylmethane leuco dye, a photoacid-producing agent, and a photoalkalizing agent uniformly dispersed in an inert organic solvent. By employing a core-shell isolated encapsulation structure, a physical barrier is constructed between the matrix resin environment and the core chemical system using the high-transmittance polymer capsule wall. This effectively prevents external substances from chemically interfering with or solvent-extracting the photosensitive reactants and dye molecules in the core during slurry leveling and subsequent matrix crosslinking. The capsule wall possesses specific dual-wavelength optical transmission characteristics, ensuring efficient transmission of light energy signals to the interior. Based on this, the core components related to color development are dissolved and pre-placed in the inert organic solvent of the capsule core, providing a homogeneous and stable micro-liquid reaction environment for the ring-opening protonation reaction of triarylmethane leuco dyes and subsequent acid-base neutralization. This improves the response sensitivity and color uniformity of photochemical conversion, laying the foundation for the stable execution of the two independent reactions of photo-induced color development and photo-induced fixing in this technical solution.

[0010] As a further improvement of the present invention, the dual-wavelength responsive microcapsule includes several color sub-class microcapsules classified according to the color spectral category of the encapsulated triarylmethane leuco dye. By controlling the selective irradiation band and spatial mask partitioning of the first wavelength light source, the photoacid-producing agent in the target color sub-class microcapsule is selectively triggered to decompose and release acidic substances, causing the corresponding leuco dye to open the ring and develop color, generating a multi-color main pattern color region composed of micro-pixels of different colors. The core composite system of each color sub-class microcapsule independently constructs an asymmetric response mechanism in which the molar ratio of the photoacid-producing agent is greater than that of the photoalkali-producing agent. The released alkaline substances only neutralize the remaining acidic substances in the already developed color region of each color system to maintain the already developed color unchanged, while completely neutralizing and deactivating the photoacid-producing agent in the undeveloped color region of each color system. By blending microcapsules of different color systems and combining them with selective exposure, composite color development of multi-color micropixels is achieved within a single coating, eliminating the need for multiple overcoats required for traditional multi-color patterns. Utilizing an independently constructed acid-base asymmetric response mechanism within the microcapsules, stoichiometric differences enable zoned state control during the global fixing stage. This mechanism allows alkaline substances generated during fixing to effectively deactivate photoacid-generating agents in undeveloped areas, preventing background color shift due to ambient light excitation, while maintaining a sufficient acidic environment in developed areas to preserve the open-ring structure of the dye. This microscopic chemical antagonism and residual suppression logic fundamentally blocks color crosstalk between microcapsules of different color systems in a single blend system, providing a material chemistry-level guarantee for the final presentation of pure and long-term stable multi-color anti-counterfeiting patterns.

[0011] As a further improvement of the present invention, the pattern color development exposure step includes: quantitatively projecting light of the first wavelength band onto the target color development area through the first mask disposed above the microcapsule coating and having microscopic optical alignment marks; during the projection process, controlling the irradiation energy of the first wavelength light source to be greater than the threshold decomposition energy of the photoacid-producing agent, so that the light penetrates the microcapsule coating longitudinally along a direction perpendicular to the substrate; by adjusting the incident angle distribution of the parallel collimated beam, making it optically matched with the refractive index of the matrix resin and the high-transmittance polymer capsule wall in the microcapsule coating, suppressing the lateral diffuse scattering of light inside the microcapsule coating of uniform physical thickness, and confining the acid-rich area generated by the decomposition of the photoacid-producing agent within the geometrical physical boundary of the direct projection of the light, thereby generating the main pattern color development area. By introducing a parallel collimated beam and constructing an optical refractive index matching mechanism adapted to the coating system, the lateral diffuse scattering phenomenon of light between different media interfaces is actively suppressed from the physical transmission path. The invisible optical field constraint replaces the traditional physical isolation of the physical microgrooves, so that the photochemical acid production reaction in the core is strictly controlled within the vertical geometric projection of the mask opening. This generates a high-resolution color pattern with sharp edges and no lateral bleeding on a continuous and flat coating. The spatial constraint maintains the initial unreacted state of the photoacid-producing agent in the undeveloped area outside the main pattern, avoiding cross-regional contamination of chemical substances. This lays a clear and pure chemical boundary foundation for the accurate and thorough neutralization and deactivation of the background color in the non-pattern area during the subsequent global fixing and bottom locking steps.

[0012] As a further improvement of the present invention, the global fixing and base locking step includes removing the mask and irradiating the substrate with a second-band light source, causing the photo-alkali-generating agent in the microcapsule core composite system to decompose and release organic bases throughout the entire area. In the main pattern color development area and the area where the hidden anti-counterfeiting graphics are located, by using a molar ratio of photo-acid-generating agent greater than that of photo-alkali-generating agent, the released organic bases neutralize only the residual free acidic substances in the color development area, preserving the color development molecular structure of the open-ring leuco dye. In the non-color development area, the released organic bases undergo an irreversible neutralization reaction with the undecomposed photo-acid-generating agent, completing the base color deactivation and color locking. By introducing full-width irradiation with a second-band light source and utilizing the pre-set acid-base asymmetric molar ratio mechanism inside the microcapsules, full-width chemical state partitioning fixing is achieved without the need for physical elution and impurity removal. Within the color-developing area, a fixed amount of organic base consumes the free activated acid, preventing dye degradation or bleeding into the surrounding non-color-developing area due to localized acid overload. This maintains the clarity and color state of the pattern. In the non-color-developing area, the irreversible neutralization reaction directly deprives the photoacid-generating agent of its subsequent photosensitive activity, effectively suppressing the secondary excitation and yellowing of the substrate base color under ambient light or ultraviolet exposure. This fixing and base-locking mechanism blocks the path of subsequent accidental photochemical reactions at the molecular structure level, significantly improving the environmental weather resistance of micro / nanostructured color-filled products. It also provides crucial chemical state protection for subsequent curing and bonding steps and the long-term visual stability of the final suspended optical product under complex lighting conditions.

[0013] The beneficial effects of this invention are: (1) Design color-developing microcapsules, and form a film by planar liquid application and surface tension self-leveling. Structurally, it eliminates the dependence of traditional microstructure color filling on micro grooves, and eliminates the physical scrubbing and scraping process of excess paste in non-pattern areas, simplifying the preparation process.

[0014] (2) By using a suspended mask and a preset spatial geometric projection misalignment, a lateral parallax is constructed in a single uniform thickness coating without the need to add a physical coating, thereby generating a concealed anti-counterfeiting pattern.

[0015] (3) By designing the core-shell structure of the microcapsule and the acid-base asymmetric response mechanism of the capsule core, the anti-crosstalk independent color development of multi-color micro pixels was realized. Furthermore, by using the partitioned chemical antagonism of the full-frame fixing to irreversibly deactivate the photosensitive material in the non-developable color area, the possibility of yellowing of the base color and secondary color change was blocked at the molecular level, thus improving the long-term visual stability of the product. Attached Figure Description

[0016] Figure 1 This is a flowchart of a micro / nano structure coloring method based on dual-wavelength response microcapsules according to the present invention.

[0017] Figure 2This is a schematic diagram of the geometric optical path according to an embodiment of the present invention.

[0018] Figure 3 This is a microscopic schematic diagram of the micro / nano structure of the present invention. Detailed Implementation

[0019] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Identical components are denoted by the same reference numerals. It should be noted that the terms "front," "rear," "left," "right," "upper," and "lower" used in the following description refer to directions in the accompanying drawings, and the terms "bottom surface," "top surface," "inner," and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0020] The first embodiment of this invention proposes a micro / nanostructure coloring method based on dual-wavelength responsive microcapsules, such as... Figures 1 to 3 As shown, it includes: The color-changing slurry preparation process involves selecting a fluid polymer with light-transmitting properties as the base resin, such as UV-curable acrylic resin or waterborne polyurethane resin. Dual-wavelength responsive microcapsules containing leuco dyes, photoacid-producing agents, and photoalkalizing agents are uniformly dispersed in the base resin at a predetermined ratio, typically 10% to 40%. A color-changing filler slurry with the target kinetic viscosity is obtained through stirring and degassing. Specifically, the dual-wavelength responsive microcapsules contain an asymmetric stoichiometric response mechanism where the molar ratio of the photoacid-producing agent is greater than that of the photoalkalizing agent. The predetermined molar ratio is 2 to 5:1. Furthermore, the photoacid-producing agent is configured to produce a decomposition response only to the first wavelength light source, and the photoalkalizing agent is configured to produce a decomposition response only to the second wavelength light source. Because it is necessary to ensure that photons from the first and second waveband light sources can penetrate the resin matrix and reach the surface of the microcapsules, providing a light energy transmission channel for subsequent independent photochemical color development and fixing reactions, the kinetic viscosity of the slurry is controlled by adjusting the mass fraction of microcapsules from 10% to 40%. This allows the prepared color-changing filling slurry to have matching flowability and surface tension, providing a material rheological basis for the slurry to achieve self-leveling filling in the micron-scale groove array of the substrate in the next step, as well as maintaining the uniformity of the microcapsule coating thickness.

[0021] Inside the microcapsules, the molar ratio of photoacid-generating agent to photoalkali-generating agent is preset to 2 to 5:1, establishing an acid-base neutralization margin suppression mechanism from the material source to ensure an excess of acidic substances released by the photoacid-generating agent in the patterned color development area. In the subsequent global fixing stage, the photoalkali-generating agent is fully excited by second-band short-wave ultraviolet light to decompose and release organic bases. In the unexposed non-color development areas, the released organic bases undergo an irreversible neutralization reaction with the undecomposed photoacid-generating agent, deactivating it to suppress yellowing of the background color. In the exposed color development areas, due to the preset ratio, the total amount of acid produced by the decomposition of the photoacid-generating agent in the early stage is higher than the amount of alkali released. The alkaline substances neutralize a small amount of remaining free acid, thereby maintaining the open-ring color development structure of the leuco dye and controlling the color difference in the color development state to within 5%. This characteristic and parameter range lays the underlying material transformation foundation for achieving the unique full-width irradiation waterless fixing and zoned chemical state control of this application.

[0022] In the substrate filling and coating step, the color-changing filler slurry is attached to the substrate surface to generate a microcapsule coating covering the target area, and the microcapsule coating is pre-cured to fix the position of the microcapsules.

[0023] Specifically, in this embodiment, the substrate filling and coating step includes selecting a planar substrate without grooves on its surface, and quantitatively guiding and distributing the flowing color-changing filler slurry onto the substrate surface using planar coating methods such as scraping, roller coating, or slot coating. Based on the slurry's preset kinetic viscosity, the color-changing filler slurry flows and merges on the substrate through its own surface tension, expanding to form a smooth liquid film continuously covering the entire target area. This smooth liquid film has a uniform physical thickness, such as 1 micrometer, in the direction perpendicular to the substrate. By employing the above-mentioned planar application combined with surface tension self-leveling film-forming mechanism, the reliance on physical wiping of excess slurry in non-patterned areas in traditional microstructure filling processes is directly eliminated from a physical structure perspective. The continuous and uniformly thick microcapsule coating not only ensures the uniformity of acid production and color development in the main patterned area through photochemical reactions, but also provides the necessary physical carrier space for constructing microscopic lateral spatial projection misalignment using tilted optical paths in subsequent anti-counterfeiting exposure steps. Simultaneously, it provides a precise refractive focal length matching thickness for the final product when bonded to the optical lens layer.

[0024] When pre-curing a smooth liquid film to form a microcapsule coating with a solid morphology, low-energy exposure is performed using first-band long-wave ultraviolet light with an energy not exceeding 100 millijoules per square centimeter, or a low-temperature drying method is used. Limiting the pre-curing energy to this low threshold ensures that the irradiation energy is insufficient to trigger the extensive decomposition of photoacid-producing agents inside the microcapsules. This both renders the slurry non-flowable, thus fixing the spatial position of the microcapsules and preventing pattern displacement in subsequent processes, while also fully preserving the photochemical reactivity of all components within the microcapsules. The pre-cured coating remains colorless, providing a pure physical and chemical foundation for the subsequent targeted high-energy exposure color development.

[0025] This invention also includes a method for spraying color-changing filler. An initial color-changing filler slurry is obtained, and an appropriate amount of matching diluent is added to it. The slurry is mixed at a set mass ratio, typically slurry:diluent = 100:10~30. The mixture is thoroughly stirred in a vacuum mixer to eliminate air bubbles, and its viscosity is adjusted to a suitable range for atomization spraying, preferably 10~50 mPa·s. After stirring, the diluted slurry is filtered using a filter screen to remove large particulate impurities and prevent nozzle clogging in subsequent processes. The substrate to be coated is placed and fixed on the platform of the spraying equipment. A precision atomization spraying device is used, with core spraying parameters set according to a nozzle diameter of 0.3 to 1 mm, atomization pressure of 0.15 to 0.4 MPa, and a spraying distance of 50 to 150 mm. The spraying equipment is started, and the nozzle is controlled to move uniformly above the substrate at a set speed, for example, 100~300 mm / s. The spraying path is set in a zigzag or mutually perpendicular intersecting grid pattern to ensure that the tiny droplets of the color-changing filler slurry can be uniformly deposited on the substrate surface after atomization. After the spraying operation is completed, the substrate is removed and allowed to stand and level for 3 to 10 minutes in a clean room temperature environment to allow the deposited droplets to fully merge and flatten, and to release the underlying air bubbles, ultimately forming a smooth and dense color-changing filler coating on the substrate.

[0026] In the pattern color development and exposure step, a first mask is set on the microcapsule coating, and selective irradiation is performed by a light source with a preset first wavelength. This causes the photoacid-producing agent in the microcapsules in the light-transmitting area to decompose and release acidic substances, triggering the ring-opening color development of the leuco dye to generate the main pattern color development area.

[0027] Specifically, in this embodiment, the pattern color development exposure step includes placing a chromium mask with a preset pattern and microscopic optical alignment marks on top of the microcapsule coating as the first mask. 365 nm long-wave ultraviolet light is used as the first wavelength light source, and light is quantitatively projected onto the target color development area through the first mask. During projection, the irradiation energy of the first wavelength light source is controlled to be maintained within the range of 800 to 2000 millijoules per square centimeter. Setting the irradiation energy within this range is to address and overcome the exponential light attenuation effect generated by light at the vertical height of the micron-level microstructure. The microcapsule particles within the coating absorb and scatter ultraviolet light, resulting in a decreasing light intensity reaching the bottom. Providing an irradiation energy of 800 to 2000 millijoules per square centimeter ensures that light penetrates the microcapsule coating with a micron-level depth along a direction perpendicular to the substrate, allowing the bottom of the microcapsules to still receive light exceeding the photo-induced acidification threshold energy. This vertical energy penetration mechanism enables photoacid-producing agents at all depth levels to decompose and release acidic substances, triggering ring-opening color development of leuco dyes and preventing color fading or loss of three-dimensionality in suspended patterns. While ensuring vertical penetration energy, the incident angle distribution of the parallel collimated beam is controlled to achieve optical matching with the refractive index of the matrix resin and the high-transmittance polymer capsule wall in the microcapsule coating. This optical mechanism suppresses lateral diffuse scattering of high-energy light within the uniformly thick microcapsule coating, confining the acid-rich areas generated by the decomposition of the photoacid-producing agents within the geometrical boundaries of direct light projection, thereby endowing the generated main pattern's color display area with micron-level resolution characteristics.

[0028] This embodiment uses a single first mask to prepare a monochrome main pattern, aiming to clearly illustrate the basic working principle of patterned selective color development. When a multi-color pattern needs to be prepared, a corresponding number of partitioned masks can be configured according to the color system types contained in the target pattern. Each mask corresponds to the target color development area of ​​a sub-category of color system microcapsules. By sequentially aligning each mask and performing selective irradiation with light sources of different wavelengths set according to the color development requirements, the photo-induced acid-producing agent in the corresponding color system microcapsules can be triggered in each partition, initiating the ring-opening color development of the corresponding leuco dye. Finally, a multi-color main pattern color development area composed of multiple color micro-pixels is formed on the same substrate.

[0029] In the multicolor blending system, the mechanism of the global fixing and base-locking step is fully compatible with that of the monochromatic system. Because each color sub-class microcapsule employs an independent core-shell encapsulation structure, the dye molecules, photosensitive components, and reaction media within the capsule core are isolated from each other by the polymer capsule wall. Both color development and fixing reactions are completed independently within their respective microcapsules, preventing cross-capsule diffusion of reaction components from different color systems. During full-width irradiation in the second global band, all microcapsules simultaneously undergo internal acid-base neutralization reactions: in the developed areas, each color microcapsule maintains its color development state through an asymmetric ratio of excess acid; in the undeveloped areas, the photoacid-generating agents within each color microcapsule are simultaneously and irreversibly neutralized and deactivated. This mechanism, from a microstructural perspective, avoids color crosstalk and boundary mixing between different color systems, ensuring the color purity and long-term stability of the multicolor pattern.

[0030] When using multi-mask spatial partitioning for overlay exposure, layer-by-layer alignment can be achieved by relying on the preset microscopic optical alignment marks on the substrate and each mask. After each mask change, the horizontal and vertical positions are first calibrated using the alignment marks to control the positional deviation between the light-transmitting area of ​​the mask and the pixel area corresponding to the target color system within the sub-micron level. Then, the corresponding color system is exposed and developed. This avoids misalignment triggering of other color system microcapsules in non-target areas, ensuring the boundary clarity between pixels of different color systems and improving the preparation accuracy of multi-color patterns.

[0031] In the global fixing and base locking step, the first mask is removed, and the substrate is fully irradiated by a light source with a preset second band, so that the photo-induced alkali-generating agent in the entire area decomposes and releases alkaline substances, neutralizing and deactivating the undecomposed photo-induced acid-generating agent in the undeveloped area, thus completing the base color locking.

[0032] Specifically, in this embodiment, the global fixing and base-locking step includes removing the mask and irradiating the substrate with 254 nm short-wave ultraviolet light as a second-band light source without a mask for a duration of 10 to 30 seconds. This full-area irradiation causes the photo-induced alkali-generating agent in the microcapsule core composite system throughout the entire area to decompose and release organic alkali. In the main pattern color development area and the area where the hidden anti-counterfeiting graphics are located, based on the molar ratio of photo-induced acid-generating agent to photo-induced alkali-generating agent, the total amount of acidic substances released in the early stage is higher than the total amount of alkaline substances released in the global fixing stage. The released organic alkali only neutralizes the remaining free acidic substances in the color development area, maintaining the color molecular structure of the opened-ring leuco dye and controlling the color difference in the color development state within a fluctuation range of less than 5%. In the undeveloped area, the released organic alkali undergoes an irreversible neutralization reaction with the undecomposed photo-induced acid-generating agent, completing the deactivation and color-locking of the base color. In the aforementioned global fixing and base-locking process, the output of 254 nm short-wave ultraviolet light is controlled by calculating and setting dynamic irradiation energy. This energy setting logic aims to overcome the problem of longitudinal light attenuation caused by the micrometer-level height. When the substrate is irradiated with short-wave ultraviolet light, if a single high energy exceeding a preset threshold is applied, the photo-alkalizing agent inside the surface microcapsules will decompose and release redundant organic alkali. The excess alkaline substances diffuse into the bottom layer of the microstructure and neutralize the acidic substances in the microcapsules that are limited in production due to previous light attenuation, causing the bottom layer of the suspended pattern to fade and the three-dimensional spatial sense to weaken. If the applied energy is below the preset lower limit, the amount of photo-alkalizing agent released in the unexposed areas of the surface is insufficient to neutralize the active photo-acidifying agent, resulting in base-locking failure in non-pattern areas. By introducing dynamic energy parameters, the equivalent amount of released alkaline substances is matched with the residual active substances on the surface, which not only blocks the longitudinal deep diffusion of alkaline substances and maintains the color saturation of the bottom pattern, but also achieves long-term stability of the background color in non-color areas.

[0033] In the curing and bonding step, the substrate with the base color locked is post-cured to stabilize the cross-linking of the matrix resin. The cured substrate pattern layer and the optical lens layer are then aligned and UV-transferred to generate a naked-eye floating pattern product.

[0034] Specifically, in this embodiment, the curing and bonding step includes applying a full-area post-curing treatment to the substrate after the base color has been locked, exposing the entire substrate surface to full-spectrum ultraviolet light with an energy of 2000 millijoules per square centimeter, or using a thermal curing treatment with a preset temperature gradient. The purpose of setting this curing energy parameter is to stimulate the transparent matrix resin in the color-changing filler slurry to undergo a cross-linking reaction, forming a structurally stable three-dimensional polymer network framework.

[0035] After the substrate pattern layer has completed cross-linking and curing, the substrate with the colored micro-pattern array and the microlens array layer, which serves as the optical lens layer, are aligned and UV-transferred. In the alignment UV transfer process, the optical refractive focal length of the cured microlens array layer is calculated in advance based on the microstructural parameters of the microlens array transfer master mold and the refractive index of the transfer UV resin. This focal length is then precisely matched with the physical thickness of the microcapsule coating. The necessity of implementing this focal length matching logic lies in the fact that, relying on the optical refractive imaging mechanism of the in-situ transferred microlens array, the planar graphic information generated by the underlying microstructure based on regional color rendering can complete the light convergence and imaging reconstruction in the vertical dimension of space, so that the optical imaging focus of the graphic is detached from the physical surface of the substrate, ultimately generating a colored naked-eye floating pattern product with spatial depth and three-dimensional stereoscopic visual characteristics. The in-situ forming method of alignment UV transfer can eliminate the focal length error introduced by the adhesive layer thickness deviation in the traditional bonding process, while ensuring the lateral alignment accuracy of the microlens and the underlying colored pattern, improving the consistency and stability of the floating imaging effect of batch products.

[0036] The second embodiment of this invention proposes a method for color-coding anti-counterfeiting labels during the coloring of micro-nano structures, such as... Figures 1 to 3 As shown, this embodiment, based on the process of Embodiment 1, adds an anti-counterfeiting pattern exposure step between the patterning color development exposure step and the global fixing and bottom locking step to prepare a micro-nano structure color-filled product with a hidden parallax anti-counterfeiting mark. In this embodiment, the process parameters for substrate pretreatment, color-changing filler preparation, substrate coating and pre-curing, and main pattern color development are consistent with those of Embodiment 1. The following only describes the relevant steps for generating the anti-counterfeiting pattern.

[0037] After the main pattern is developed and exposed, the first mask is removed, and a second mask with anti-counterfeiting graphics is placed above the microcapsule coating. The mask is raised using a rigid support structure distributed along the non-pattern edge areas, ensuring a uniform vertical gap between the lower surface of the mask and the upper surface of the microcapsule coating. This gap value matches the microscopic refractive focal length of the subsequently bonded optical lens layer. This suspended placement avoids direct contact between the mask and the incompletely cured microcapsule coating, preventing scratches on the coating surface and displacement of the internal microcapsules, thus ensuring the structural integrity of the main pattern. Furthermore, the air gap between the mask and the coating provides lateral deflection space for oblique light rays, allowing light to project a laterally displaced image onto the coating surface after passing through the mask's transparent area. This provides the physical basis for generating a misaligned anti-counterfeiting pattern within the same coating plane. Matching the gap value to the lens focal length ensures that the final anti-counterfeiting pattern offset matches the imaging resolution range of the microlens, placing the anti-counterfeiting pattern in a blind spot at a normal viewing angle but allowing clear observation at a specific oblique viewing angle.

[0038] The anti-counterfeiting graphic area of ​​the second mask corresponds to the blank, non-coloring area between the main pattern. Tilt exposure only triggers a color reaction in the microcapsules within the blank area, without affecting the already color-developed main pattern area. The photoacid-producing agent within the main pattern area has already decomposed in the previous process; secondary irradiation will not change the existing color state. Clearly defining the area correspondence ensures the independence of the main pattern and the anti-counterfeiting pattern, preventing interference with the color and boundaries of the main pattern during anti-counterfeiting exposure, and guaranteeing a stable visual effect for the final product. After deployment, the incident direction of the long-wave ultraviolet light source is adjusted so that the light is projected onto the surface of the second mask at a preset tilt angle. After passing through the light-transmitting area of ​​the mask, the light crosses the gap between the mask and the coating along the tilt direction, finally projecting onto the microcapsule coating surface. The projection position is laterally offset relative to the vertical projection position of the light-transmitting area of ​​the mask. Controlling the incident angle of the light source during exposure keeps it stable, ensuring a uniform projection offset across the entire mask. By employing an oblique incident light path design, the principle of spatial geometric projection can be used to transform the longitudinal gap between the mask and the coating into a lateral projection offset within the coating plane. This eliminates the need for additional coating or overprinting steps, generating a misaligned anti-counterfeiting pattern within the same coating plane as the main pattern. Since the anti-counterfeiting pattern and the main pattern are on the same physical level, it does not increase the overall thickness of the product or affect the subsequent bonding accuracy with the optical lens layer.

[0039] The upper limit of the lateral offset of the anti-counterfeiting pattern is determined based on the lateral pitch of the individual lenses in the optical lens layer. Parameter matching follows the logic of fixed benchmark and single-variable adjustment. First, the physical suspension span is determined based on the refractive focal length of the optical lens layer to ensure the correspondence between the gap and the focal length. On this basis, the final lateral offset is controlled by adjusting the tilt angle of the light: the larger the tilt angle of the light, the greater the lateral offset of the anti-counterfeiting pattern. By gradually fine-tuning the incident angle, the offset can be controlled within the preset upper limit range. By adopting the matching method of fixing the span first and then adjusting the angle, the offset of the anti-counterfeiting pattern can be precisely controlled while ensuring the lens focal length matching, avoiding the increased process debugging complexity caused by adjusting two parameters at the same time, and ensuring the stability of the final parallax anti-counterfeiting effect. The vertical gap height of the mask and the tilt angle of the light source are adjusted so that the lateral offset of the final generated anti-counterfeiting pattern relative to the main pattern does not exceed half of the individual lens pitch. Constraining the upper limit of the lateral offset can prevent the offset from exceeding the imaging period of a single microlens and prevent problems such as visual ghosting and chaotic anti-counterfeiting pattern resolution. By controlling the offset within this range, the microlens array can accurately distinguish the parallax information between the main pattern and the anti-counterfeiting pattern, achieving the effect that the anti-counterfeiting pattern is obscured by the main pattern when viewed directly, and the anti-counterfeiting pattern is displayed independently when viewed from an oblique angle.

[0040] Before tilting the exposure, the exposure energy is increased proportionally to the extension of the light's propagation path after tilting, based on the baseline energy of vertical exposure. The larger the tilt angle, the greater the extension of the propagation path, and the greater the corresponding increase in exposure energy. After energy adjustment, it is ensured that even after the tilted light penetrates the entire coating thickness, the microcapsules at the bottom of the coating can still receive sufficient light for decomposition, triggering the decomposition of photoacid-producing agents and the development of leuco pigments. Using an energy adjustment method that matches the path extension ratio can accurately compensate for the light intensity loss caused by the extended optical path, avoiding overexposure of the surface layer due to excessive energy or insufficient color development of the underlying layer due to insufficient energy, thus ensuring the uniformity of color development in the depth direction of the anti-counterfeiting pattern. The propagation path of tilted light inside the coating is longer than that of vertically incident light. Microcapsule particles absorb and scatter light, and the extended path leads to a decrease in the light intensity received at the bottom of the coating. Correspondingly increasing the exposure energy can compensate for the light intensity loss caused by tilted propagation, ensuring the uniformity of color development in the depth direction of the coating, avoiding uneven color development in the depth direction of the anti-counterfeiting pattern, and ensuring the stability of the final visual effect of the suspended anti-counterfeiting pattern.

[0041] After the anti-counterfeiting pattern exposure is completed, the second mask is removed, and global fixing, post-curing, and UV transfer processes for optical lens layer alignment are performed according to the same parameters as in Example 1. This results in a naked-eye suspended pattern product with a hidden parallax anti-counterfeiting mark. When viewed directly, the anti-counterfeiting pattern is hidden within the visual range of the main pattern, with no obvious visual traces. When viewed at a specific tilt angle, the anti-counterfeiting pattern is clearly visible, achieving a view-dependent anti-counterfeiting effect.

[0042] The third embodiment of the present invention proposes a dual-wavelength responsive microcapsule, such as... Figures 1 to 3 As shown, the dual-wavelength responsive microcapsule is a core-shell isolated encapsulation structure. The core-shell isolated encapsulation structure includes a high-transmittance polymer capsule wall and a core composite system. The high-transmittance polymer capsule wall has an optical transmittance that allows light sources of the first and second wavelength bands to pass through. The core composite system includes a triarylmethane leuco dye, a photoacid generator, and a photoalkali generator uniformly dispersed in an inert organic solvent.

[0043] This embodiment specifically describes the dual-wavelength-responsive microcapsules used in the aforementioned embodiments. These microcapsules are the core functional unit of the micro / nanostructure color-filling process, fabricated using a core-shell isolated encapsulation structure. They are suitable for planar substrate filling scenarios and can stably achieve two-level control of patterned color development and global fixing. The dual-wavelength-responsive microcapsule is a core-shell isolated encapsulation structure composed of a high-transmittance polymer capsule wall and an inner capsule core composite system. The capsule wall is made of polyurethane or polymethyl methacrylate polymers, which have high light transmittance in both long-wave and short-wave ultraviolet bands, ensuring that light in the first and second wavelength bands can smoothly penetrate the capsule wall to reach the inner capsule core. Simultaneously, the polymer capsule wall possesses dense chemical barrier properties, isolating the reaction components of the capsule core from the external matrix resin environment. This prevents solvents or crosslinking components from seeping into the capsule core during the matrix resin curing process and interfering with the color development reaction, and also prevents the dye and photosensitive components inside the capsule core from diffusing outwards and causing background color contamination. The core-shell isolated encapsulation provides an independent and stable reaction environment for the color development reaction at the microscale, ensuring precise and controllable color development and fixing reactions. The core-capsule composite system consists of a triarylmethane leuco dye, a photoacid generator, and a photoalkali generator uniformly dispersed in an inert organic solvent. The triarylmethane leuco dye initially possesses a colorless, closed-ring structure. Upon contact with acidic substances, it undergoes a ring-opening reaction, exhibiting a stable color with clear color boundaries, suitable for the high-resolution color development requirements of micro / nanostructure color filling. The photoacid generator only responds to the first band of long-wave ultraviolet light, absorbing light energy and releasing organic acids to trigger dye color development. The photoalkali generator only responds to the second band of short-wave ultraviolet light, absorbing light energy and releasing organic bases for neutralization and fixing. The response bands of the two photosensitive components are independent of each other, with no cross-response, allowing for independent control of the color development and fixing processes, avoiding interference between the two steps.

[0044] The dual-wavelength responsive microcapsules in this embodiment were prepared by in-situ polymerization. The specific preparation process is as follows: To prepare the core oil phase, a pre-prepared ratio of leuco dye, photoacid generator, and photoalkali generator was added to an inert organic solvent such as ethyl acetate. The mixture was continuously stirred until all components were completely dissolved, forming a homogeneous oil phase solution. Subsequently, an aqueous phase was prepared by dissolving an emulsifier in deionized water and stirring until completely dissolved, forming a continuous aqueous system. The oil phase was slowly added to the aqueous system, and high-speed shear emulsification was used to disperse the oil phase into uniform microdroplets with a droplet size controlled between 500 nanometers and 5 micrometers. After emulsification, polymer monomers and reaction auxiliaries were added to the system, and the temperature was raised and maintained at a stable temperature, allowing the monomers to gradually polymerize on the surface of the oil phase droplets, forming a dense polymer capsule wall. After the reaction, the product was filtered, washed, and dried to obtain a powdered dual-wavelength responsive microcapsule product. The microcapsules prepared using the in-situ polymerization process exhibit uniform particle size distribution, controllable capsule wall thickness, and stable sealing performance, making them suitable for subsequent slurry preparation and coating processes, avoiding problems such as capsule wall rupture and component leakage during processing. Dual-wavelength responsive microcapsules can be prepared into sub-capsules of different color systems based on the different color emission spectra of the encapsulated leuco dyes. The conventional basic color systems include red, yellow, and blue. The sub-capsules of different color systems differ only in the type of leuco dye encapsulated internally; the selection of capsule wall materials, photosensitive components, and response wavelengths remain consistent. When preparing multi-color filling products, sub-capsules of different color systems can be mixed in a preset ratio and dispersed in a matrix resin to obtain a full-color filling slurry. During the color filling process, photomasks corresponding to different color system pixel areas are used for zoned alignment and exposure. Microcapsules in the target area receive light and trigger color development, while microcapsules in non-target areas remain colorless due to lack of light. After sequentially exposing the corresponding areas of different color systems, a multi-color pattern composed of microscopic pixels of different colors can be formed within the same coating. Using microcapsules to encapsulate different color systems of dyes allows the color development reactions of different color systems to occur in their respective independent core environments, avoiding color crosstalk caused by mutual interference between different dye molecules and ensuring the color purity of each pixel area. Meanwhile, the blended microcapsules combined with zoned exposure allow for multi-color pattern preparation with a single coating, eliminating the need for multiple coatings and overprinting, thus simplifying the multi-color filling process. In the sub-capsules of various color systems, the molar amount of photoacid-generating agent within the core is consistently higher than that of photoalkali-generating agent, typically set to two to five times. This ratio design provides the chemical basis for zoned control in the global fixing process and is a core prerequisite for achieving color retention in the developing areas and bottom locking in the non-developing areas. In the developed areas, the photoacid-generating agent from the previous exposure process has completely decomposed and released acidic substances, with the total amount of acidic substances exceeding the total amount of alkaline substances released by the photoalkali-generating agent in the subsequent fixing process. During fixing, the alkaline substances can only neutralize the remaining free acidic substances within the area and cannot completely consume the acidic environment within the system. The open-ring color-developing structure of the leuco dye is preserved, and the pattern color does not significantly decay. In the non-developed areas, the photoacid-generating agent remains in its initial intact state.The alkaline substances released during the fixing process can undergo an irreversible neutralization reaction with the undecomposed photoacid-producing agent, permanently eliminating its ability to decompose and produce acid. Even if this area is subsequently exposed to the first wavelength of light, dye development will not be triggered, achieving permanent stability of the background color in non-patterned areas. This asymmetrical ratio design allows for simultaneous color stabilization in the developing area and deactivation of the background color in the non-developing area through a single full-frame fixing irradiation, eliminating the need for zoning or water washing processes and making it suitable for full-area filling processes.

[0045] The dual-wavelength responsive microcapsules prepared in this embodiment can be directly adapted to the coloring process of the first and second embodiments described above, meeting the preparation needs of different types of micro-nano structure coloring products.

[0046] The foregoing has illustrated and described the basic features, principles, and advantages of the present invention. It should be noted that the present invention is not limited to the above embodiments, but only to some embodiments. Any improvements and additions made without departing from the spirit and scope of the present invention are considered to be within the scope of protection of the present invention.

Claims

1. A micro / nanostructure coloring method based on dual-wavelength responsive microcapsules, characterized in that, include: The color-changing slurry preparation step involves dispersing dual-wavelength responsive microcapsules in a matrix resin to prepare a color-changing filler slurry, wherein the microcapsules include leuco dyes, photoacid generators, and photoalkali generators. In the substrate filling and coating step, the color-changing filler slurry is attached to the substrate surface to generate a microcapsule coating covering the target area, and the microcapsule coating is pre-cured to fix the position of the microcapsules. In the pattern color development and exposure step, a first mask is set on the microcapsule coating, and selective irradiation is performed by a light source with a preset first wavelength, so that the photoacid-producing agent of the microcapsule in the light-transmitting area decomposes and releases acidic substances, triggering the ring-opening color development of the leuco dye to generate the main pattern color development area. In the global fixing and base locking step, the first mask is removed, and the substrate is fully irradiated by a light source with a preset second band, so that the photo-induced alkali-generating agent in the entire area decomposes and releases alkaline substances, neutralizes and deactivates the undecomposed photo-induced acid-generating agent in the undeveloped area, and completes the base color locking. In the curing and bonding step, the substrate with the base color locked is post-cured to stabilize the cross-linking of the matrix resin. The cured substrate pattern layer and the optical lens layer are then aligned and UV-transferred to generate a naked-eye floating pattern product.

2. The micro / nano structure coloring method based on dual-wavelength response microcapsules according to claim 1, characterized in that, The substrate filling and coating step includes quantitatively guiding and distributing a flowing color-changing filler slurry onto the substrate surface through a liquid application method such as planar coating or droplet spraying; the color-changing filler slurry itself flows and merges on the substrate through its surface tension, expanding to form a smooth liquid film that continuously covers the entire target area; the smooth liquid film has a uniform physical thickness in the direction perpendicular to the substrate; and the smooth liquid film is pre-cured to form a microcapsule coating with a solid morphology.

3. The micro / nano structure coloring method based on dual-wavelength response microcapsules according to claim 1, characterized in that, It also includes an anti-counterfeiting pattern exposure step. After the pattern is exposed, a second mask with an anti-counterfeiting pattern is set on the microcapsule coating. The second mask and the surface of the microcapsule coating maintain a preset physical suspension span. The thickness of the preset physical suspension span matches the microscopic refractive focal length of the optical lens layer. The physical suspension span is used as the longitudinal depth space to construct the physical boundary of multi-view suspended optical parallax in a two-dimensional plane.

4. The micro / nano structure coloring method based on dual-wavelength response microcapsules according to claim 3, characterized in that, The anti-counterfeiting pattern exposure step further includes guiding the light passing through the second mask through a preset tilt angle according to the light source of the first band. According to the physical suspension span of the second mask and the uniform physical thickness of the microcapsule coating, the light is spatially projected and misaligned in the microcapsule coating in the lateral direction, triggering the photo-induced acid-producing agent of the microcapsules outside the main pattern color area to decompose and release acidic substances, generating an anti-counterfeiting pattern that is on the same physical reference plane as the main pattern color area and has a lateral parallax offset.

5. The micro / nano structure coloring method based on dual-wavelength response microcapsules according to claim 4, characterized in that, The anti-counterfeiting pattern exposure step further includes obtaining the microscopic optical modulation period based on the physical pitch of the individual lenses in the optical lens layer, determining the upper limit of the target lateral offset of the anti-counterfeiting pattern relative to the color display area of ​​the main pattern based on the microscopic optical modulation period, and using the target lateral offset as a control target. Based on the uniform physical thickness of the microcapsule coating, the geometric linkage relationship between the physical suspension span and the preset tilt angle is derived and matched. Based on the deep exponential attenuation characteristic of the microcapsule for ultraviolet light intensity, the exposure threshold of the light energy of the secondary guided irradiation is increased by the incremental extension of the actual penetration path inside the microcapsule coating at the preset tilt angle, to compensate for the scattering attenuation loss of tilted penetration.

6. The micro / nano structure coloring method based on dual-wavelength response microcapsules according to claim 1, characterized in that, The dual-wavelength responsive microcapsule has a core-shell isolated encapsulation structure, which includes a high-transmittance polymer capsule wall and a core composite system. The high-transmittance polymer capsule wall has an optical transmittance that allows light sources of the first and second wavelength bands to pass through. The core composite system includes a triarylmethane leuco dye, a photoacid generator, and a photoalkali generator uniformly dispersed in an inert organic solvent.

7. The micro / nano structure coloring method based on dual-wavelength response microcapsules according to claim 6, characterized in that, The dual-wavelength responsive microcapsules include several color sub-capsules classified according to the chromogenic spectrum of the encapsulated triarylmethane leuco dye. By controlling the selective irradiation band and spatial mask partitioning of the first wavelength light source, the photoacid-producing agent in the target color sub-capsule is selectively triggered to decompose and release acidic substances, causing the corresponding leuco dye to open the ring and develop color, generating a multi-color main pattern color region composed of micro-pixels of different colors. The core composite system of each color sub-capsule independently constructs an asymmetric response mechanism in which the molar ratio of the photoacid-producing agent is greater than that of the photoalkali-producing agent. The released alkaline substances only neutralize the remaining acidic substances in the already developed color region of each color system to maintain the already developed color, while completely neutralizing and deactivating the photoacid-producing agent in the undeveloped color region of each color system.

8. The micro / nano structure coloring method based on dual-wavelength response microcapsules according to claim 1, characterized in that, The pattern color development and exposure step includes: quantitatively projecting light of the first wavelength band onto the target color development area through a first mask disposed above the microcapsule coating and bearing microscopic aerodynamic alignment marks; during the projection process, controlling the irradiation energy of the first wavelength light source to be greater than the threshold decomposition energy of the photoacid-producing agent, so that the light penetrates the microcapsule coating longitudinally along a direction perpendicular to the substrate; by adjusting the incident angle distribution of the parallel collimated beam, optically matching it with the refractive index of the matrix resin and the high-transmittance polymer capsule wall in the microcapsule coating, suppressing the lateral diffuse scattering of light inside the microcapsule coating of uniform physical thickness, and confining the acid-rich area generated by the decomposition of the photoacid-producing agent within the geometrical physical boundary of the direct projection of the light, thereby generating the main pattern color development area.

9. The micro / nano structure coloring method based on dual-wavelength response microcapsules according to claim 1, characterized in that, The global fixing and locking process includes removing the mask and irradiating the substrate with a second-band light source to decompose the photoalkali-generating agent in the microcapsule core composite system throughout the entire area, releasing organic alkali. In the main pattern color development area and the area where the hidden anti-counterfeiting graphics are located, the molar ratio of the photoacid-generating agent to the photoalkali-generating agent is greater than that of the photoalkali-generating agent, so that the released organic alkali only neutralizes the free acidic substances remaining in the color development area, retaining the color development molecular structure of the open-ring leuco dye. In the uncolor development area, the released organic alkali undergoes an irreversible neutralization reaction with the undecomposed photoacid-generating agent, completing the base color deactivation and color locking.

Images