Nanometer printing plate roller process

Abstract

The invention relates to the field of nanometer printing plate rollers, and discloses a nanometer printing plate roller technology which comprises the following steps that a, a cylindrical plate roller blank is prepared, and the surface of the cylindrical plate roller blank is provided with a cascade reaction functional layer; b, according to a preset two-dimensional diffraction pattern, generating a digital blueprint containing target height information of each nano convex structure; and c, selectively irradiating the cascade reaction functional layer according to the digital blueprint, and triggering a physical and chemical cascade reaction in an irradiated area to expand the volume of the irradiated area. The physical and chemical cascade reaction process is monitored in real time, and the energy output of the maintaining pulse is dynamically adjusted according to the deviation between the chemical reaction characteristic spectrum and the preset target in the reaction, so that the disturbance caused by the non-uniformity of the material micro-area or the laser energy drift is actively compensated; and it is ensured that the nanometer protrusion structures formed on the surface of the whole cylindrical plate roller blank have high consistency, and then the yield is guaranteed.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of nano printing plate roller, in particular to a nano printing plate roller process. BACKGROUND

[0002] The printing plate roller with micro or nano surface structure is a key mold for manufacturing diffractive optical elements. This kind of plate roller can copy the precise three-dimensional topography of the surface to the film by embossing or rolling on the substrate such as transparent film, so that it has specific optical diffraction or light refraction ability, thereby presenting holographic image, special texture or dynamic light change effect. Therefore, this kind of technology is widely used in product anti-counterfeiting identification, decorative packaging and optical display fields.

[0003] At present, the mainstream technology for manufacturing such high-precision plate roller includes diamond ultra-precision machining, photolithography technology and laser direct writing technology. Diamond ultra-precision machining can manufacture regular structures with optical level surface quality, but it has limited processing capacity for complex and non-periodic diffraction patterns. Although the technology represented by electron beam lithography has extremely high processing resolution, the processing process is extremely time-consuming and the cost is high, which is difficult to meet the demand of large area and high efficiency manufacturing in industrial production.

[0004] As a more efficient processing method, laser direct writing technology is used to directly build three-dimensional structures on the surface of plate roller substrate. However, the traditional laser direct writing technology usually runs in open loop control mode, that is, the laser energy parameters are preset according to theoretical calculation or experimental calibration, and remain unchanged during the processing. This control strategy inherently assumes that the output of the laser system and the characteristics of the functional layer material are completely uniform and stable. However, in actual large area manufacturing, factors such as laser energy drift caused by long time work and material micro zone non-uniformity are almost unavoidable. Due to the lack of real-time feedback and correction mechanism, these disturbances will directly translate into processing errors of the final structure, resulting in inconsistent height of nano protruding structures in different areas, which seriously restricts the manufacturing precision and yield of large area, high quality diffractive plate roller. SUMMARY

[0005] In view of the defects of the prior art, the present application provides a nano printing plate roller process, which solves the problem.

[0006] To achieve the above purpose, the present application is realized by the following technical scheme: a nano printing plate roller process; comprising the following steps: First, a layer of cascade reaction functional layer containing controlled reaction path is constructed on the surface of the cylindrical plate roller blank. Then, two-dimensional digital information is accurately converted into three-dimensional physical structure.

[0007] The specific technical scheme includes the following steps: First, a cylindrical master roll blank is prepared, and a layer of cascade reaction functional layer is formed on the surface thereof. The functional layer is a composite film, which is composed of a metastable amorphous alloy matrix as a continuous phase, and a plurality of reaction energy core nanocapsules as a dispersed phase, which are dispersedly distributed in the matrix. The reaction energy core nanocapsules have a core-shell structure, in which the core is an intermetallic compound precursor particle, and the shell is a thin shell of inert medium.

[0008] Second, a digital blueprint containing the height information of each nano-protrusion structure is generated according to a preset two-dimensional diffraction pattern. The generation process includes two stages of calculation. In the first stage, the local gray value at any coordinate in the two-dimensional diffraction pattern is converted into the corresponding basic target height by a preset mapping function. ; In the formula, h(x, y) is the basic target height calculated at the coordinate (x, y); G(x, y) is the local gray value at the coordinate (x, y) in the two-dimensional diffraction pattern; Gmin is the minimum value of the gray scale range (for example, 0); Gmax is the maximum value of the gray scale range (for example, 255); hmin is the lowest basic target height of the nano-protrusion structure, corresponding to the minimum gray value; hmax is the highest basic target height of the nano-protrusion structure, corresponding to the maximum gray value. In the second stage, in order to eliminate periodic diffraction noise and introduce encodable physical features, a pseudo-random perturbation quantity is calculated in real time by a deterministic pseudo-random function based on the coordinates (x, y) of the nano-protrusion structure and a preset key.

[0009] In an embodiment, the calculation process is as follows: ; ; In the formula, h(x, y) is the basic target height calculated at the coordinate (x, y); G(x, y) is the local gray value at the coordinate (x, y) in the two-dimensional diffraction pattern; Gmin is the minimum value of the gray scale range (for example, 0); Gmax is the maximum value of the gray scale range (for example, 255); hmin is the lowest basic target height of the nano-protrusion structure, corresponding to the minimum gray value; hmax is the highest basic target height of the nano-protrusion structure, corresponding to the maximum gray value. The maximum value that can be reached is hmax-hmin.

[0010] Finally, the two are superimposed to obtain the final target height h(x, y) of the coordinate point: ​​​​; In the formula: coordinates The final target altitude; For coordinates The calculated base target height; For coordinates The pseudo-random perturbation quantity calculated at the location.

[0011] Finally, a pulse-shaping laser, guided by instructions from the digital blueprint, is used to position and selectively irradiate the cascade reaction functional layers via four-axis synchronous motion. The composite pulse train emitted by the laser consists of an ignition pulse and a sustaining pulse. The ignition pulse, with its high peak power, instantaneously raises the material temperature, triggering an amorphous-to-crystalline physical phase transition in the metastable amorphous alloy matrix, while simultaneously disrupting the inert dielectric shell structure of the reaction energy core nanocapsules. The sustaining pulse, with its relatively low peak power and tunable energy, provides continuous energy to the exposed intermetallic compound precursor particles, precisely controlling the progress of their in-situ exothermic chemical reaction.

[0012] The aforementioned physical phase transition and chemical reaction constitute a physicochemical cascade reaction. This reaction causes the volume of the irradiated area to expand, fundamentally because the overall density of the products (crystalline phase and intermetallic compounds) is less than the overall density of the reactants (amorphous phase and precursor particles). Since the amount of volume expansion is directly related to the degree of completion of the chemical reaction, and the degree of completion is regulated by the energy of the sustaining pulse injection, precise control of the height of the final formed nanoprotrusion structure can be achieved by controlling the energy of the sustaining pulse.

[0013] To further improve processing accuracy and stability, this technical solution also includes a closed-loop feedback control process. During laser irradiation, the transient optical radiation spectrum generated in the reaction region is acquired in real time via a spectral acquisition system. This spectral signal includes a broadband thermal radiation background corresponding to the physical phase transition and characteristic atomic emission lines corresponding to the chemical reaction. The control system compares the real-time separated characteristic chemical reaction spectrum with the preset target reaction spectrum to obtain a deviation signal. Based on this deviation signal, a control algorithm (such as a PID algorithm) calculates the adjustment amount of the laser energy in real time and immediately applies it to the energy or pulse width setting of subsequent sustaining pulses. This proactively compensates for potential disturbances during processing, ensuring that the nano-protrusion structures manufactured on the entire roller surface achieve the precise height required by the digital blueprint.

[0014] This invention provides a nano-printing roller process. It has the following beneficial effects: 1. This invention monitors the physicochemical cascade reaction process in real time and dynamically adjusts the energy output of the maintenance pulse based on the deviation between the characteristic spectrum of the chemical reaction and the preset target. This actively compensates for the disturbances introduced by the inhomogeneity of the material micro-regions or the laser energy drift, ensuring that the nano-protrusion structure formed on the entire cylindrical plate roll blank has a high degree of consistency, thereby guaranteeing the yield rate.

[0015] 2. This invention defines a specific target height for each nanoprotrusion structure using a digital blueprint; by monitoring the reaction process in real time through a closed-loop feedback control process, it can ensure that the final volume expansion strictly corresponds to the instructions of the digital blueprint, thereby improving control accuracy. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the process flow of the present invention; Figure 2 This is a schematic diagram of the digital blueprint generation process of the present invention; Figure 3 This is a schematic diagram of the four-axis machining process of the present invention; Figure 4 This is a schematic diagram of the closed-loop feedback control of the present invention. Detailed Implementation

[0017] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] To better understand the present invention, the above content will be described in detail below with reference to specific embodiments.

[0019] Please see the appendix Figure 1 - Appendix Figure 4 This invention provides a nano-printing roller process, which includes: Step a: Prepare a special cascade reaction functional layer that serves as an energy and reaction carrier. This functional layer is formed on the surface of a pretreated cylindrical roll blank using techniques such as physical vapor deposition. Its interior consists of a metastable amorphous alloy matrix and reactive energy core nanocapsules dispersed within it.

[0020] Step b: Based on the preset two-dimensional diffraction pattern, generate a digital blueprint containing the target height information of each nano-protrusion structure; map the local grayscale of the pattern to the base target height.

[0021] Step c involves using a pulsed shaping laser to selectively irradiate the functional layer according to the digital blueprint. The laser emits a composite pulse train consisting of an ignition pulse and a sustaining pulse, which precisely triggers a physicochemical cascade reaction within the irradiated area: first, a physical phase transition occurs in the amorphous matrix, and the released heat immediately triggers a violent in-situ exothermic chemical reaction in the precursor within the nanocapsules. This, in turn, causes a precisely controllable volume expansion in the irradiated area due to the decrease in product density, thereby forming a nano-protrusion structure on the roller surface that perfectly corresponds to the digital blueprint.

[0022] In one specific embodiment, in the overall process flow, the substrate material used to support the cascade reaction functional layer first needs to be precisely pretreated in order to prepare a cylindrical plate roll blank that meets the requirements of subsequent processes.

[0023] Specifically, materials with high rigidity, high thermal stability, and wear resistance are selected as the matrix, such as cemented carbide (e.g., tungsten carbide-based cemented carbide) or high-rigidity steel that has undergone quenching and tempering. After selecting the material, it can be processed through precision machining processes. In the initial stage, precision turning technology is used to manufacture the macroscopic geometry of the cylindrical matrix to ensure its basic roundness, cylindricity, and coaxiality.

[0024] Based on this, in order to further improve geometric accuracy and surface quality, grinding can be used to treat the surface of the turned substrate. The grinding process can use an abrasive wheel to remove the micro-undulations and machining marks left by the previous process under controlled feed rate and rotation speed, so that the various dimensional and positional tolerances of the cylindrical substrate can reach the micrometer level.

[0025] To obtain a nanoscale smooth surface for subsequent thin film deposition, the ground substrate requires final grinding and polishing. This step can be performed using diamond abrasive paste or chemical mechanical polishing (CMP) slurry on specialized polishing equipment. Through the synergistic effect of mechanical friction and chemical action, the surface roughness is gradually reduced. The ultimate goal of this process is to achieve a surface roughness Ra of nanometers for the cylindrical roll blank, while controlling its radial runout error (RRO) within a preset micrometer-level threshold.

[0026] After completing all the above machining processes, residual polishing agent, oil, and microparticles on the surface must be removed. The finished cylindrical printing roll blank is then placed in deionized water or a specific organic solvent (such as acetone or ethanol) for multiple ultrasonic cleaning cycles, and finally dried in a clean nitrogen environment. Through these steps, a clean, smooth cylindrical printing roll blank with a precision surface can be obtained.

[0027] After obtaining a cylindrical roll blank with a dense surface, a cascaded reactive functional layer with a thickness of micrometers can be grown by physical vapor deposition (PVD) technology.

[0028] The cascaded reactive functional layer is a composite material comprising a metastable amorphous alloy matrix and multiple reactive energy core nanocapsules dispersed within the metastable amorphous alloy matrix. The two are synchronously and in-situ constructed within a vacuum chamber using a multi-target magnetron sputtering composite process.

[0029] The metastable amorphous alloy substrate is formed through a multi-target magnetron co-sputtering process. Specifically, various high-purity metal targets are placed in a high-vacuum sputtering chamber and simultaneously sputtered under an inert gas atmosphere (such as high-purity argon) by applying DC or RF power. High-speed ionized metal atoms or ions rapidly condense on the surface of a cylindrical printing plate blank with controlled substrate temperature. Due to the extremely high cooling rate, the atoms do not have time to achieve long-range ordered arrangement, thus forming a dense, uniform glassy thin film, i.e., the metastable amorphous alloy substrate. In one specific embodiment, zirconium, copper, aluminum, and nickel targets can be selected for co-sputtering to form the zirconium-based amorphous alloy; in another embodiment, iron, cobalt, boron, silicon, and other targets can be selected to form the iron-based amorphous alloy. Furthermore, this substrate itself is in a metastable state with high Gibbs free energy, providing an intrinsic driving force for subsequent physical phase transitions under laser irradiation.

[0030] During the deposition of the metastable amorphous alloy matrix, by introducing additional target material and controlled reactive gas, the reactive energy core nanocapsules are constructed simultaneously and in situ, ensuring that the reactive energy core nanocapsules can be uniformly embedded in the entire matrix material in an isolated and diffuse state.

[0031] Specifically, each reactive core nanocapsule is composed of intermetallic compound precursor particles encased in an inert medium shell. In one specific embodiment, the intermetallic compound precursor particles can be nanoclusters of titanium (Ti) and aluminum (Al) particles, formed by simultaneously sputtering high-purity titanium and high-purity aluminum targets during the main sputtering process. To form the inert medium shell encasing the precursor particles, trace amounts of reactive gases, such as oxygen or nitrogen, can be periodically or continuously introduced into the vacuum chamber during sputtering, precisely controlled by a mass flow meter. These reactive gases will react with the sputtered highly reactive metal atoms (such as aluminum atoms) to generate an ultrathin, chemically stable ceramic layer, several nanometers thick, on the surface of the titanium-aluminum nanoclusters, such as alumina (Al₂O₃) or titanium nitride (TiN). The inert medium shell acts as a physical barrier and a chemical passivator at room temperature and pressure, stably encapsulating highly active precursor particles inside the capsule and preventing them from spontaneously reacting during the deposition process or storage until they are triggered by a laser pulse of specific energy.

[0032] Therefore, through the above-mentioned composite deposition process, a cascade reaction functional layer with controllable chemical reaction energy was finally obtained on the surface of the cylindrical roll blank. This functional layer is used to achieve volume expansion and form a nano-protrusion structure by laser-induced local physical phase change and chemical reaction.

[0033] The metastable amorphous alloy substrate in the cascade reaction functional layer is deposited in an ultra-high vacuum multi-target magnetron sputtering system. A pre-treated cylindrical plate blank is loaded onto a rotating sample stage within the vacuum chamber, and the base vacuum level within the chamber is brought to a specific high vacuum standard. Subsequently, a controlled flow of high-purity inert working gas, typically argon, is introduced into the chamber to maintain a stable sputtering pressure environment.

[0034] Furthermore, this process can employ multi-target co-sputtering technology. Within a vacuum chamber, multiple high-purity metal or non-metal targets are configured according to the composition of the target alloy. By applying independent DC or RF sputtering power to each target, atoms on the target surface are bombarded and sputtered by high-energy argon ions. These sputtered atoms or atomic clusters move at high speeds and ultimately deposit on the surface of a slowly rotating cylindrical roll blank with strictly controlled substrate temperature. Because the deposition rate is much greater than the rate at which atoms diffuse and align on the substrate surface, the atoms are instantly frozen in disordered positions upon reaching the substrate surface, unable to form a long-range ordered crystal structure. This results in a dense, uniform amorphous thin film, i.e., the metastable amorphous alloy matrix.

[0035] In one specific embodiment, to form the zirconium-based amorphous alloy, zirconium (Zr), copper (Cu), aluminum (Al), and nickel (Ni) targets with a purity higher than 99.99% can be configured in the sputtering system. By adjusting the sputtering power applied to each target, the atomic percentage of each element in the deposited film can be precisely controlled, thereby obtaining a zirconium-based amorphous alloy with specific glass-forming capabilities and mechanical properties.

[0036] In another embodiment, to form the aforementioned iron-based amorphous alloy, iron (Fe), cobalt (Co), boron (B), silicon (Si), and other targets can be used for co-sputtering. Similarly, by adjusting the power of each target, iron-based amorphous alloy substrates with different magnetic and mechanical properties can be obtained.

[0037] In the co-sputtering process, there is a clear correlation between the atomic percentage of any element in the final deposited film and the power applied to each target. The mathematical expression for this relationship is: ; In the formula, Target element in thin film atomic percentage; To apply to the element The corresponding sputtering power on the target material; To apply to the element The corresponding sputtering power on the target material; For elements The combined sputtering and deposition coefficient, which is related to the sputtering yield, atomic mass, and geometry of the sputtering system of the element; For elements The combined sputtering and deposition coefficient, which is related to the sputtering yield, atomic mass, and geometry of the sputtering system of the element; The total number of targets participating in co-sputtering.

[0038] By controlling the power of each target material, a dense and uniform metastable amorphous alloy substrate film with a predetermined composition can be obtained. Due to its disordered atomic arrangement, it is in a high Gibbs free energy state, which can provide a thermodynamic driving force for the amorphous-crystalline physical phase transition under subsequent laser pulse action.

[0039] This process also incorporates additional target materials and controlled reactive gases during sputtering to construct and embed multiple reactive core nanocapsules in situ. The core of these reactive core nanocapsules, namely intermetallic compound precursor particles, is formed during sputtering by co-sputtering two or more highly chemically reactive metal targets. In one specific embodiment, in addition to the target material used to form the matrix, high-purity titanium (Ti) and aluminum (Al) targets are additionally configured in the sputtering chamber. When these targets are sputtered, the ionized titanium and aluminum atoms collide and aggregate upon reaching the surface of the printing roll blank or during gas-phase transport, forming stoichiometric, nanoscale titanium-aluminum atom clusters. These clusters constitute the intermetallic compound precursor particles.

[0040] To ensure the efficiency and products of subsequent chemical reactions, the atomic ratios of each component in the intermetallic compound precursor particles need to be controlled. For example, the atomic ratios of precursor elements A and B, titanium and aluminum, need to be carefully controlled. This can be achieved by adjusting the sputtering power of each target material, and the relationship is determined by the following formula: ; Elements in precursor particles With elements atomic ratio; Target element in precursor particles atomic percentage; Target element in precursor particles atomic percentage; To apply to the element The corresponding sputtering power on the target material; To apply to the element The corresponding sputtering power on the target material; For elements The combined sputtering and deposition coefficient, which is related to the sputtering yield, atomic mass, and geometry of the sputtering system of the element; For elements The combined sputtering and deposition coefficient is related to the sputtering yield, atomic mass, and geometry of the sputtering system.

[0041] Simultaneously with the formation of these intermetallic compound precursor particles, a minute amount of reactive gas (such as oxygen or nitrogen) is precisely introduced into the vacuum chamber via a mass flow controller to generate an in-situ inert dielectric shell on their surface. These reactive gases selectively react with the most reactive metal atoms on the precursor particle surface (e.g., aluminum reacts more readily with oxygen than titanium), forming a dense, chemically stable ceramic layer only a few nanometers thick, such as alumina (Al₂O₃).l The in-situ generated inert dielectric shell serves a dual purpose of physical isolation and chemical passivation. It effectively isolates the highly reactive intermetallic compound precursor particles from the metastable amorphous alloy matrix, preventing premature and uncontrolled chemical reactions during deposition, storage, or subsequent processing. This forms a core-shell structured reactive energy nanocapsule.

[0042] After the cascade reaction functional layer is prepared, a digital blueprint containing the height information of each nanoprotrusion structure target needs to be generated. This digital blueprint will serve as the basis for subsequent laser processing.

[0043] Specifically, the preset two-dimensional diffraction pattern can be a digitized image file containing specific optical information (such as holographic information or specific texture). The image can be composed of a two-dimensional pixel matrix, where each pixel has a specific local grayscale value. These grayscale values ​​are usually quantized within a standard range; for example, for an 8-bit grayscale image, the grayscale value range is from 0 (pure black) to 255 (pure white).

[0044] The first step in generating a digital blueprint is to convert the local grayscale information of each pixel in the two-dimensional diffraction pattern into the corresponding basic target height through a preset mapping function.

[0045] In one specific embodiment, this mapping relationship can be defined using a linear function. For any coordinate in a two-dimensional diffraction pattern... The pixel, and its corresponding base target height. The calculation formula is: ; In the formula, For coordinates The calculated base target height; Coordinates in a two-dimensional diffraction pattern The local grayscale value at that location; The minimum value of the grayscale range used (e.g., 0); The maximum value of the grayscale range used (e.g., 255); The minimum basic target height of the set nanoprotrusion structure corresponds to the minimum grayscale value; The maximum grayscale value corresponds to the highest base target height of the set nanoprotrusion structure.

[0046] Therefore, by performing the above calculations on each pixel in the two-dimensional diffraction RTF pattern, a two-dimensional data matrix with the same size as the original pattern can be generated. Each value in this matrix represents the basic target height of the nano-protrusion structure to be formed at the corresponding position on the roller surface.

[0047] After obtaining the basic target height at each coordinate point, in order to eliminate the periodic diffraction noise that may be introduced by the pixelation characteristics of the two-dimensional diffraction pattern, and to introduce coded and verifiable encryption features into the final nanostructure, this process further introduces and superimposes pseudo-random perturbation.

[0048] The pseudo-random perturbation quantity described in this invention is not a pre-stored random value table, but rather is generated in real time using a deterministic pseudo-random function based on the coordinates of the nano-protrusion structure and a preset key serving as the encryption seed. This generation method ensures that the perturbation quantity is unique and deterministic for each coordinate point, and is unpredictable and uncopyable without knowing the key.

[0049] In one specific implementation, the deterministic pseudo-random function employs a cryptographically secure hash algorithm, such as the SHA-256 secure hash algorithm. For any coordinate of the nanobump structure... The algorithm combines the coordinate value with a preset key (e.g., through string concatenation) to form a unique input data string. The hash algorithm then operates on this input data string to generate a fixed-length binary hash value.

[0050] A portion of this binary hash value is truncated and converted to a decimal or floating-point number. Then, through a linear transformation, it is normalized and mapped to a highly perturbed range, allowing the calculation of the pseudo-random perturbation corresponding to that coordinate point. The calculation formula is: ; In the formula, For coordinates The pseudo-random perturbation quantity calculated at the location; The maximum height disturbance amplitude is set. For coordinates The numerical value converted from the hash value generated by the key; for The maximum value that can be reached.

[0051] After calculating the corresponding coordinates After obtaining the pseudo-random perturbation, it is compared with the base target height obtained in the previous step. The layers are superimposed to obtain the final target height of the nano-protrusion structure containing the encrypted information. The formula is as follows: ; In the formula: coordinates The final target altitude; For coordinates The calculated base target height; For coordinates The pseudo-random perturbation quantity calculated at the location.

[0052] By repeating this process on all coordinate points covered by the preset two-dimensional diffraction pattern, a complete digital blueprint containing the height information of each nano-protrusion structure target is generated, which can be used to guide subsequent laser processing.

[0053] After the digital blueprint containing the final target height information is generated, the process flow moves to the physical realization stage, where a pulse-shaping laser is used to selectively irradiate the cascade reaction functional layers. This step is accomplished using a laser micromachining system capable of four-axis synchronous motion.

[0054] Specifically, the core of this processing system lies in four-axis synchronous motion, which can realize the coordinated control of the rotational motion of the printing roller blank, the axial motion of the optical system carrying the laser spot, the two-dimensional scanning motion of the laser spot, and dynamic focusing, thereby accurately mapping the coordinate points on the two-dimensional digital blueprint onto the three-dimensional cylindrical surface.

[0055] Specifically, the rotation of the printing roller blank is achieved by a spindle driven by a high-precision servo motor, forming the system's rotation axis (C-axis). This rotation provides circumferential address encoding for laser processing, while the components carrying the entire laser spot scanning and focusing optical system are mounted on a linear motion platform that moves along the geometric axis of the printing roller blank, forming the system's axial motion axis (Z-axis). The rotational motion of the C-axis and the linear motion of the Z-axis combine to complete the positioning of the printing roller surface.

[0056] During processing, the central motion controller decomposes the coordinate points in the digital blueprint into macroscopic positioning commands and microscopic scanning commands. The correspondence between the global position of the coordinate points on the unfolding plane of the printing roller and each motion axis is as follows: ; ; ; In the formula, The target position for the axial movement of the optical system; The target angle for the rotational motion of the printing roller blank; The radius of the printing roller blank; The microscopic deflection amount that the two-dimensional galvanometer scanning system needs to perform is a function calculated based on the relative position of the target point within the current processing sub-region; and These represent the global coordinates of the target point on the unfolded two-dimensional machining plane; It is a mapping and correction function that maps local relative coordinates to microscopic deflection commands of a two-dimensional galvanometer scanning system; The local relative coordinates of the target point within the current processing sub-region.

[0057] Finally, through the precise synchronization and coordinated operation of the four motion axes, each target height instruction in the digital blueprint can be transformed into an operation to locate and illuminate a specific area on the surface of the printing roller.

[0058] When a pulsed laser, positioned by the four-axis synchronous motion system, irradiates a selected area of ​​the cascade reaction functional layer, a physicochemical cascade reaction can occur on the surface of the printing plate roller blank. Specifically, the first stage of the reaction process begins with the absorption of laser photon energy by the metastable amorphous alloy matrix. As the temperature of the irradiated area rises and exceeds the glass transition temperature and crystallization temperature of the amorphous alloy material, the first reaction, namely the amorphous-crystalline physical phase transition, is triggered. During this process, atoms that were originally in a high Gibbs free energy, long-range disordered arrangement, gain sufficient migration ability under thermal drive and spontaneously rearrange into a lower-energy, long-range ordered crystal structure. This is an exothermic process, releasing the latent heat of crystallization inherent in the material.

[0059] The latent heat of crystallization released in the first stage, combined with the energy injected by the laser pulse, acts on the reactive core nanocapsule, thereby disrupting the integrity of the inert medium shell, for example, by causing it to crack or melt directly through thermal stress. The failure of the shell exposes the highly chemically active precursor particles (such as the titanium-aluminum nanoclusters mentioned above) that have been stably encapsulated within it to a high-temperature environment.

[0060] Then, the precursor particles are exposed, and the reaction enters the second stage, which is an in-situ exothermic chemical reaction. At this time, a solid-state chemical reaction occurs between the precursor particles (such as Ti and Al) to form a stable intermetallic compound (such as TiAl). This chemical reaction releases a huge chemical enthalpy, and the heat released is greater than the latent heat of crystallization released by the physical phase transition in the first stage. Therefore, the heat released by the amorphous-crystalline physical phase transition can provide energy for the subsequent chemical reaction; and the subsequent in-situ exothermic chemical reaction provides the energy needed to form the nanostructure.

[0061] The fundamental reason for the volume expansion of the irradiated area is that the density of the products generated in the physicochemical cascade reaction is less than the density of the reactants, and this volume expansion effect is due to the superposition of two contributions. First, when the metastable amorphous alloy matrix transforms from a high-density, long-range disordered state to a relatively ordered crystal structure, it will experience a certain volume change due to the change in the atomic packing mode.

[0062] The more significant volume expansion primarily stems from the in-situ exothermic chemical reaction occurring within the reactive core nanocapsules. Taking titanium and aluminum as precursors for intermetallic compounds as an example, when they react to form titanium-aluminum intermetallic compounds, although the total mass remains constant, the molar volume changes due to the specific crystal structure and interatomic spacing of the product, which differs from the reactant mixture. For various exothermic reaction systems, the crystal structure of the product exhibits lower atomic packing efficiency compared to the close-packed structure of the reactant elements, resulting in a significantly lower density of the product than the weighted average density of the reactants under the same conditions.

[0063] This leads to a decrease in the density of reactants to products, which directly results in an increase in volume. Macroscopically, this manifests as a net increase in material volume, and the magnitude of this volume expansion is directly related to the degree of reaction completion, which in turn is regulated by the injected laser energy.

[0064] Furthermore, the laser spot energy can be generated using a composite pulse train with a specific temporal energy distribution, produced by a pulse-shaping laser. This composite pulse train consists of an ignition pulse and a sustaining pulse. By sequentially outputting these two pulses in time and applying them to the same region of the material, precise step-by-step control of complex cascade reactions can be achieved. The ignition pulse in the composite pulse train, due to its high peak power and extremely short pulse width, can provide instantaneous high energy density to trigger the initial physical phase transition in the physicochemical cascade reaction. Specifically, its energy is rapidly absorbed by the metastable amorphous alloy matrix on the surface of the cascade reaction functional layer, causing the local temperature to exceed the glass transition temperature and crystallization temperature of the material in a very short time, thereby initiating the amorphous-to-crystalline physical phase transition process.

[0065] At the same time, the intense thermal shock and accompanying stress wave generated by the ignition pulse disrupt the structural integrity of the reactive energy core nanocapsules dispersed in the matrix. This disruptive effect causes the inert medium shell encapsulating the intermetallic compound precursor particles to rupture or melt, thereby removing the physical isolation of the highly reactive precursor inside.

[0066] After the ignition pulse completes its triggering and cell disruption, a sustaining pulse is immediately applied to the same area. Unlike the ignition pulse, the sustaining pulse has a relatively low peak power and a long pulse width, thus allowing for the regulation of the chemical reaction process in the physicochemical cascade reaction. This provides a controlled and continuous energy input to the exposed precursor particles, maintaining the temperature of the reaction region within the optimal window for the formation of intermetallic compounds.

[0067] Therefore, by adjusting the sustaining energy or pulse width, the total heat injected into the reaction system can be directly controlled, thereby determining the degree of completion of the precursor chemical reaction. Since the final height of the nanoprotrusion structure is directly related to the degree of reaction completion and the corresponding volume expansion, the regulation of the sustaining pulse achieves precise control of the target height of the nanoprotrusion structure.

[0068] In one embodiment, before processing, a deterministic correspondence between the total energy injected into the material and the final height of the nanoprotrusion structure can be established in advance through process calibration experiments. Then, based on the specific target height value corresponding to each coordinate point in the digital blueprint, the total energy required to form the target height can be calculated in reverse through this preset correspondence.

[0069] However, since the energy of the ignition pulse is a fixed value set to ensure the reaction starts, it remains constant throughout the entire processing. Therefore, the total energy value calculated in the previous step can be subtracted from this fixed ignition pulse energy value, and the resulting difference is the energy that needs to be provided by the sustaining pulse. This calculation process is performed independently and dynamically for each coordinate point in the digital blueprint, thereby generating a sustaining pulse with a specific energy that matches the target height for each micro-region to be processed.

[0070] Building upon the stepwise control of cascade reactions via composite pulse trains, this invention further provides a closed-loop feedback control process to ensure the uniformity of the nanoprotrusion structure height and the stability of the processing. This process is used to compensate in real time for potential disturbances introduced by factors such as micro-region inhomogeneities in the material or minor energy drifts in the laser system, thereby controlling the actual physicochemical reaction process along a preset target trajectory.

[0071] Specifically, this closed-loop feedback control first requires the acquisition of transient optical radiation spectra generated during the physicochemical cascade reaction. This can be achieved using a focusing lens, optical fiber, and a high-response-rate spectrometer (such as an enhanced charge-coupled device spectrometer) to capture all spectral information emitted by the reaction region within the nanosecond to microsecond range.

[0072] The acquired raw signal, namely the transient optical radiation spectrum, is a composite spectrum formed by the superposition of light radiation generated by different physicochemical processes. To achieve effective feedback control, it is necessary to separate and identify the characteristic spectra corresponding to the physical phase transition and the chemical reaction, respectively. Specifically, the transient optical radiation spectrum includes: The characteristic spectrum of physical phase transitions is mainly characterized by a broadband thermal radiation background that originates from the heating of the material and follows Planck's law. This spectrum is a smooth, continuous curve, and its peak wavelength and overall intensity are directly related to the instantaneous temperature of the reaction zone.

[0073] The characteristic spectrum of a chemical reaction, superimposed on this broadband thermal radiation background, consists of a series of discrete, sharp atomic emission lines. When excited precursor atoms (such as titanium and aluminum) transition back to lower energy levels, they emit their inherent characteristic spectral lines with strictly defined wavelengths.

[0074] The analysis of transient optical radiation spectra is algorithmically performed as a signal decomposition process. This is applied to the spectral intensity signals acquired in real time. Its mathematical model can be described as follows: ; In the formula, The transient optical radiation spectral intensity acquired in real time is the wavelength. and time The function; The characteristic spectrum of the physical phase transition is the broadband thermal radiation background portion. The characteristic spectrum of the chemical reaction is composed of emission lines from characteristic atoms. In the control algorithm, a thermal radiation background is established by curve fitting to the continuous spectral region that does not contain atomic emission lines. By using the model and subtracting the background from the original signal, the pure chemical reaction characteristic spectrum can be separated. .

[0075] After successfully separating the characteristic spectra that can characterize the chemical reaction process, the characteristic spectra of the chemical reaction separated in real time are first... Characteristic spectra of the pre-defined target chemical reaction Comparison. The characteristic spectrum of the target chemical reaction. The standard spectral morphology that can be determined during the initial process calibration to generate the ideal nanostructure. The deviation signal is obtained by subtracting the two spectra; the specific formula is as follows: ; In the formula, To convert the spectral deviation information into scalar commands usable by the controller, the deviation signal needs to be integrated over a wavelength range covering the emission lines of key atoms, thus obtaining a comprehensive integrated deviation. .

[0076] Based on this integral deviation, the required adjustment of the laser energy is calculated in real time using a proportional-integral-derivative (PID) control algorithm. This adjustment is specifically used to correct the energy setting of the sustain pulse in a composite pulse train, and its expression is: ; In the formula, This is the calculated sustain pulse energy adjustment amount; , , These are the proportional, integral, and derivative gain coefficients, respectively. The negative sign indicates that this is a negative feedback control mechanism.

[0077] Ultimately, this calculated energy adjustment is immediately applied to the next sustain pulse to be emitted, specifically by adjusting the energy or pulse width of the sustain pulse in real time. By cyclically executing a closed-loop process of acquisition, comparison, calculation, and compensation at extremely high frequencies at each processing point, any deviation from the ideal reaction trajectory can be proactively and rapidly corrected, ensuring that the completion of the chemical reaction is precisely controlled. This guarantees that the nano-protrusion structures manufactured across the entire roller surface achieve the precise height required by the digital blueprint.

Claims

1. A nano-printed plate roller process characterized by, The method comprises the following steps: a. preparing a cylindrical roller blank, a surface of the cylindrical roller blank having a cascade reaction functional layer; b. generating a digital blueprint containing target height information of each nano-protrusion structure according to a preset two-dimensional diffraction pattern; c. using a pulse shaping laser to selectively irradiate the cascade reaction functional layer according to the digital blueprint, triggering a physical and chemical cascade reaction in the irradiated area, and making the irradiated area volume expand, so as to form nano-protrusion structures corresponding to the digital blueprint on the surface of the cylindrical roller blank.

2. A nano gravure roll process according to claim 1, wherein The cascade reaction functional layer comprises: a metastable amorphous alloy matrix; reaction energy core nanocapsules dispersed in the metastable amorphous alloy matrix.

3. A nano gravure roll process according to claim 2, wherein The metastable amorphous alloy matrix is a zirconium-based amorphous alloy or an iron-based amorphous alloy; The reaction energy core nanocapsules comprise intermetallic compound precursor particles wrapped by an inert medium shell.

4. A nano gravure roll process according to claim 1, wherein In step c, the selective irradiation of the cascade reaction functional layer is achieved by four-axis synchronous motion, which is used to control the rotational motion of the roller blank, the axial motion of the optical system carrying the laser spot, the two-dimensional scanning motion of the laser spot, and dynamic focusing.

5. A nano gravure roll process as claimed in claim 1, wherein, In the digital blueprint, the target height of each nano-protrusion structure is obtained by superimposing a basic target height corresponding to the local gray scale of the preset two-dimensional diffraction pattern and a preset pseudo-random disturbance according to the coordinates of the nano-protrusion structure.

6. A nano gravure roll process according to claim 1, wherein In step c, the selective irradiation by the pulse shaping laser is specifically achieved by using a composite pulse train composed of a firing pulse and a one-dimensional maintenance pulse for irradiation. The firing pulse is used to trigger the initial physical phase change in the physical and chemical cascade reaction and to destroy the structural integrity of the reaction energy core nanocapsules. The maintenance pulse is used to regulate the chemical reaction process in the physical and chemical cascade reaction.

7. A nano gravure roll process according to claim 2, wherein The physical and chemical cascade reaction comprises: an amorphous-crystalline physical phase change occurring in the metastable amorphous alloy matrix; an in-situ exothermic chemical reaction occurring in the precursor in the reaction energy core nanocapsules.

8. A nano gravure roll process according to claim 1, wherein Step c further comprises a closed-loop feedback control process, which specifically comprises: c1. collecting a transient optical radiation spectrum generated during the physical and chemical cascade reaction in real time while irradiating with a laser; c2. comparing the transient optical radiation spectrum with a preset target reaction spectrum to obtain a deviation signal; c3. adjusting the energy output of the pulse shaping laser in real time according to the deviation signal to reduce the difference between the transient optical radiation spectrum and the target reaction spectrum.

9. A nano gravure roll process according to claim 8, wherein, The transient optical radiation spectrum comprises: characteristic spectra of the physical phase change and the chemical reaction; In step c3, the energy output of the pulse shaping laser is adjusted in real time, specifically the energy or pulse width of the maintenance pulse is adjusted in real time.

10. A nano gravure roll process according to claim 1, wherein The volume expansion of the irradiated area is caused by the fact that the density of the product generated in the physical and chemical cascade reaction is smaller than the density of the reactant.

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