Laser painting based on aluminum-based materials and its anti-counterfeiting method and system

Abstract

This invention discloses a laser painting method and system based on aluminum-based materials for anti-counterfeiting. The method includes: transferring prepared ink onto a glass substrate using a pipette, and fixing the glass substrate to a laser processing system; focusing a laser beam at the interface between the ink and the glass substrate, inducing the growth of aluminum hydroxide micro / nano structures on the substrate surface through the local photothermal effect of the laser; segmenting and slicing the image to be processed to generate point cloud data; controlling the focused laser beam to perform two-dimensional patterned scanning based on the point cloud data, and adjusting the structural color exhibited by the aluminum hydroxide microstructure during the scanning process; removing the glass substrate from the laser processing system, and subsequently rinsing it with deionized water and drying it with nitrogen to achieve aluminum-based structural color painting; and using a solution etching method to encrypt the painted information and implement anti-counterfeiting labels. This invention realizes laser painting, information encryption, and anti-counterfeiting for monochrome and multicolor aluminum-based structural color devices.

Description

Technical Field

[0001] This invention relates to the fields of laser processing and label anti-counterfeiting, and in particular to a laser painting method and system based on aluminum-based materials for anti-counterfeiting. Background Technology

[0002] Structural color is produced by the reflection, refraction, scattering, or interference of light by the microscopic structure of an object's surface or interior. Its color development relies on the fine structure of biological surfaces, and color changes can be achieved by altering the observer's angle or the periodic structure of the surface. Current main processing methods for structural color include inkjet printing, which controls the distribution, thickness, and arrangement of ink droplets to form microscopic periodic structures; electron beam lithography, which precisely controls the scanning path and energy of the electron beam to etch microscopic structures of different sizes, shapes, and arrangements; and nanoimprint lithography, which uses physical imprinting to transfer nanoscale structures onto a substrate surface to create periodic or regular nanostructures. These processing methods suffer from drawbacks such as low resolution, poor ink stability, complex processing techniques, slow speed, high cost, and high substrate requirements.

[0003] Laser direct writing technology, as an advanced micro-nano fabrication method, possesses advantages such as high energy density, extremely small heat-affected zone, and excellent processing resolution, attracting widespread attention from researchers both domestically and internationally. The focal point of a laser beam can be considered a flexible and controllable miniature reactor, which can be used to achieve high-precision point-to-point preparation of materials. To this end, researchers have attempted to use lasers as a heat source to process thin films of different thicknesses and periods on different endothermic substrates in a single step, controlling the color by changing the film thickness. However, this method suffers from drawbacks such as the need for a costly cleanroom environment, complex and costly coating processes, and material waste in subtractive manufacturing. Furthermore, it has limitations in terms of anti-counterfeiting and encryption effects for structural colors. Summary of the Invention

[0004] The main objective of this invention is to provide a laser painting method and system based on aluminum-based materials for anti-counterfeiting. It establishes the range of optimized process parameters for aluminum hydroxide microstructure and the dynamic control range of structural color. Furthermore, this invention achieves reversible color changes in laser-painted patterns through solution corrosion, thus realizing information encryption and anti-counterfeiting.

[0005] To achieve the aforementioned objectives, the present invention employs the following solution:

[0006] One aspect of the present invention provides a laser painting method based on aluminum-based materials and its anti-counterfeiting method, comprising:

[0007] Step 1: Transfer the prepared ink onto the glass substrate using a pipette, and then fix the glass substrate into the laser processing system;

[0008] Step 2: Focus the laser beam onto the interface between the ink and the glass substrate. Through the local photothermal effect of the laser, aluminum hydroxide micro-nano structures can be induced to grow on the substrate surface.

[0009] Step 3: The image to be processed is segmented and sliced ​​sequentially to generate point cloud data;

[0010] Step 4: Based on the point cloud data, control the focused laser beam to perform two-dimensional patterning scanning. During the scanning process, control the laser exposure time and laser power to quantitatively control the geometric parameters of the aluminum hydroxide microstructure, and finally quantitatively regulate the structural color of the aluminum hydroxide microstructure.

[0011] Step 5: Remove the glass substrate from the laser processing system, rinse it with deionized water and dry it with nitrogen gas to finally achieve the color painting of the aluminum-based structural color;

[0012] Step Six: Use solution etching method to encrypt the painted information and prevent label counterfeiting.

[0013] In one embodiment, the ink is composed of sodium aluminum nitrate hydroxide; the specific preparation method of the ink is as follows:

[0014] Weigh aluminum nitrate nonahydrate and sodium hydroxide solid reagents precisely according to a 500 mM molar concentration.

[0015] The mixed solution was prepared using a fractional dissolution method;

[0016] Add a stir bar and stir at a constant speed on a magnetic stirrer for half an hour. After the reaction is complete, let it stand for one hour, take the supernatant and filter it to prepare an aluminum nitrate solution containing sodium ions.

[0017] In one embodiment, the laser processing system includes a half-wave plate, a Glan Taylor prism, an acousto-optic modulator, a pinhole, a galvanometer, a first lens, a second lens, and a light-emitting diode (LED). The laser power is initially controlled by the combination of the half-wave plate and the Glan Taylor prism. The acousto-optic modulator is used for further fine-tuning of the laser power. The pinhole is used for spatial filtering of the laser beam. The galvanometer is used for beam deflection. The first and second lenses deflect the beam to the entrance pupil of the objective lens. The LED is used for illumination during camera observation during the processing.

[0018] In one embodiment, the segmentation process includes: first performing grayscale processing on the image to be processed to obtain a grayscale histogram of the entire image; then dividing the entire image into two regions, namely a black region and a white region, through global threshold segmentation; wherein the black region is the target object region and the white region is the background region.

[0019] In one embodiment, the slicing process includes optimizing the sliced ​​file by adjusting the image scaling and the single-point exposure spacing; wherein the single-point spacing of the slices is set to 500 nm.

[0020] In one embodiment, the method of using solution etching to encrypt painted information and prevent label counterfeiting specifically includes: dripping a zirconium oxynitrate solution onto the surface of a glass substrate, focusing a laser onto the surface of the glass substrate to generate a local high-temperature field that induces the zirconium oxynitrate solution to form a zirconium oxide QR code pattern, and then dripping the ink onto the surface of the zirconium oxide QR code pattern to process a layer of aluminum hydroxide pattern on the surface of the zirconium oxide QR code pattern, thereby hiding the zirconium oxide QR code pattern inside and encrypting the information.

[0021] Another aspect of the present invention provides a laser painting system based on aluminum-based materials and its anti-counterfeiting system, comprising:

[0022] Glass substrate fixing module: used to transfer the prepared ink onto the glass substrate using a pipette and fix the glass substrate to the laser processing system;

[0023] Structure forming module: used to focus the laser beam to the interface between the ink and the glass substrate, and induce the growth of aluminum hydroxide micro and nano structures on the substrate surface through the local photothermal effect of the laser;

[0024] The image processing module is used to segment and slice the image to be processed, and finally generate point cloud data.

[0025] The color painting quantitative control module is used to control the focused laser beam to perform two-dimensional pattern scanning based on point cloud data. During the scanning process, the laser exposure time and laser power are controlled to quantitatively control the geometric parameters of the aluminum hydroxide microstructure, and finally quantitatively control the structural color of the aluminum hydroxide microstructure.

[0026] The color painting module is used to remove the glass substrate from the laser processing system, use deionized water for subsequent rinsing and nitrogen drying, and finally achieve the color painting of aluminum-based structural colors.

[0027] The anti-counterfeiting module is used to encrypt the painted information and prevent the label from being counterfeited by using a solution etching method.

[0028] In one embodiment, the ink is composed of aluminum nitrate and sodium hydroxide; the specific preparation method of the ink is as follows:

[0029] Weigh aluminum nitrate nonahydrate and sodium hydroxide solid reagents precisely according to a 500 mM molar concentration.

[0030] The mixed solution was prepared using a fractional dissolution method;

[0031] Add a stir bar and stir at a constant speed on a magnetic stirrer for half an hour. After the reaction is complete, let it stand for one hour, take the supernatant and filter it to prepare an aluminum nitrate solution containing sodium ions.

[0032] In one embodiment, the laser processing system includes a half-wave plate, a Glan Taylor prism, an acousto-optic modulator, a pinhole, a galvanometer, a first lens, a second lens, and a light-emitting diode (LED). The laser power is initially controlled by the combination of the half-wave plate and the Glan Taylor prism. The acousto-optic modulator is used for further fine-tuning of the laser power. The pinhole is used for spatial filtering of the laser beam. The galvanometer is used for beam deflection. The first and second lenses deflect the beam to the entrance pupil of the objective lens. The LED is used for illumination during camera observation during the processing.

[0033] In one embodiment, the image processing module further includes a segmentation module, which is used to first perform grayscale processing on the image to be processed to obtain a grayscale histogram of the entire image, and then divide the entire image into two regions, namely a black region and a white region, by global threshold segmentation; wherein the black region is the target object region and the white region is the background region.

[0034] In one embodiment, the image processing module further includes a slicing module for optimizing the sliced ​​file by adjusting the image scaling and the single-point exposure spacing; wherein the single-point spacing of the slices is set to 500 nm.

[0035] In one embodiment, the anti-counterfeiting module further includes:

[0036] A QR code generation module is used to form a zirconium oxide QR code pattern on the surface of a glass substrate using laser.

[0037] The QR code hiding module is used to process an aluminum hydroxide pattern on the surface of the zirconia QR code pattern to hide the QR code pattern inside, thereby encrypting the information.

[0038] Compared with the prior art, the present invention has at least the following advantages:

[0039] (1) The present invention provides a laser painting method and system based on aluminum-based materials and its anti-counterfeiting method and system. The aluminum-based structural color laser painting technology used has high precision and can realize submicron scale structural design and processing.

[0040] (2) The present invention provides a laser painting method and system based on aluminum-based materials and its anti-counterfeiting method and system. The aluminum-based structural color laser painting technology used has low material consumption, the painted patterns can be recycled and the cost is low.

[0041] (3) The present invention provides a laser painting method and system based on aluminum-based materials and its anti-counterfeiting method and system. The laser painting process is simple and does not require complicated process flow and strict clean room environment.

[0042] (4) The present invention provides a laser painting method and system based on aluminum-based materials and its anti-counterfeiting method and system. The pattern structure of the laser painting is controllable, and compared with inkjet printing, it has the advantages of good stability and not easy to fade.

[0043] (5) The present invention provides a laser painting method and system based on aluminum-based materials and its anti-counterfeiting method and system. The structure processed by the laser can be flexibly encrypted and protected against counterfeiting through solution corrosion.

[0044] (6) For the design and implementation of anti-counterfeiting encryption for high-value-added products, the embodiment of the present invention provides an excellent solution for laser painting based on aluminum-based materials and its anti-counterfeiting method and system, which can prevent counterfeiting without affecting the aesthetics of the product. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] Figure 1 This is a schematic diagram of a laser painting and anti-counterfeiting method based on aluminum-based materials, provided in a typical embodiment of the present invention.

[0047] Figure 2 This is a physical image of aluminum hydroxide ink provided in a typical embodiment of the present invention;

[0048] Figure 3 This is a schematic diagram of a laser processing system provided in a typical embodiment of the present invention;

[0049] Figure 4a , Figure 4b This is a schematic diagram illustrating the quantitative control of the structure by processing parameters provided in a typical embodiment of the present invention;

[0050] Figure 5 This is a schematic diagram of processing large-area color blocks provided in a typical embodiment of the present invention;

[0051] Figure 6 This is a schematic diagram of the fabrication of a multicolor structural color device provided in a typical embodiment of the present invention;

[0052] Figure 7This is a schematic diagram of the information encryption and decryption process provided in a typical embodiment of the present invention. Detailed Implementation

[0053] To make the objectives, technical solutions, and advantages of the present invention clearer, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Examples of these preferred embodiments are illustrated in the drawings. The embodiments of the present invention shown in and described with reference to the drawings are merely exemplary, and the present invention is not limited to these embodiments.

[0054] In a typical implementation scheme, a laser-engraved anti-counterfeiting system based on aluminum-based materials includes:

[0055] Glass substrate fixing module: used to transfer the prepared ink onto the glass substrate using a pipette and fix the glass substrate to the laser processing system;

[0056] Structure forming module: used to focus the laser beam to the interface between the ink and the glass substrate, and induce the growth of aluminum hydroxide micro and nano structures on the substrate surface through the local photothermal effect of the laser;

[0057] The image processing module is used to segment and slice the image to be processed, and finally generate point cloud data.

[0058] The color painting quantitative control module is used to control the focused laser beam to perform two-dimensional pattern scanning based on point cloud data. During the scanning process, the laser exposure time and laser power are controlled to quantitatively control the geometric parameters of the aluminum hydroxide microstructure, and finally quantitatively control the structural color of the aluminum hydroxide microstructure.

[0059] The color painting module is used to remove the glass substrate from the laser processing system, and then use deionized water for subsequent rinsing and nitrogen drying to finally achieve the color painting of the aluminum-based structural color.

[0060] The anti-counterfeiting module is used to encrypt the painted information and prevent the label from being counterfeited by using a solution etching method.

[0061] In one embodiment, the ink is composed of aluminum nitrate and sodium hydroxide; the specific preparation method of the ink is as follows:

[0062] Weigh aluminum nitrate nonahydrate and sodium hydroxide solid reagents precisely according to a 500 mM molar concentration.

[0063] The mixed solution was prepared using a fractional dissolution method;

[0064] Add a stir bar and stir at a constant speed on a magnetic stirrer for half an hour. After the reaction is complete, let it stand for one hour, take the supernatant and filter it to prepare an aluminum nitrate solution containing sodium ions.

[0065] In one embodiment, the laser processing system includes a half-wave plate, a Glan Taylor prism, an acousto-optic modulator, a pinhole, a galvanometer, a first lens, a second lens, and a light-emitting diode (LED). The 532 nm laser power is initially controlled by the combination of the half-wave plate and the Glan Taylor prism. The acousto-optic modulator is used for further fine-tuning of the laser power. The pinhole is used for spatial filtering of the laser beam. The galvanometer is used for beam deflection. The first and second lenses deflect the beam to the entrance pupil of the objective lens. The LED is used for illumination during camera observation during the processing.

[0066] In one embodiment, the image processing module further includes a segmentation module, which is used to first perform grayscale processing on the image to be processed to obtain a grayscale histogram of the entire image, and then divide the entire image into two regions, namely a black region and a white region, by global threshold segmentation; wherein the black region is the target object region and the white region is the background region.

[0067] In one embodiment, the image processing module further includes a slicing module for optimizing the sliced ​​file by adjusting the image scaling and the single-point exposure spacing; wherein the single-point spacing of the slices is set to 500 nm.

[0068] In one embodiment, the anti-counterfeiting module further includes:

[0069] A QR code generation module is used to form a zirconium oxide QR code pattern on the surface of a glass substrate using laser.

[0070] The QR code hiding module is used to process an aluminum hydroxide pattern on the surface of the zirconia QR code pattern to hide the QR code pattern inside, thereby encrypting the information.

[0071] In a typical implementation case, such as Figure 1 As shown, a laser painting method based on aluminum-based materials and its anti-counterfeiting method specifically includes the following steps:

[0072] Step 1: Transfer the prepared ink onto the glass substrate using a pipette, and then fix the glass substrate into the laser processing system;

[0073] Step 2: Focus the laser beam onto the interface between the ink and the glass substrate. Through the local photothermal effect of the laser, aluminum hydroxide micro-nano structures can be induced to grow on the surface of the glass substrate.

[0074] Step 3: The image to be processed is segmented and sliced ​​sequentially to generate point cloud data;

[0075] Step 4: Based on the point cloud data, control the focused laser beam to perform two-dimensional patterning scanning. During the scanning process, control the laser exposure time and laser power to quantitatively control the geometric parameters of the aluminum hydroxide microstructure, and finally quantitatively regulate the structural color of the aluminum hydroxide microstructure.

[0076] Step 5: Remove the glass substrate from the laser processing system, rinse it with deionized water and dry it with nitrogen gas to finally achieve the color painting of the aluminum-based structural color;

[0077] Step Six: Use solution etching method to encrypt the painted information and prevent label counterfeiting.

[0078] To achieve a denser aluminum hydroxide structure, an ink formulation consisting of aluminum nitrate solution and solid sodium hydroxide is used. A sample of the aluminum hydroxide ink is shown below. Figure 2 As shown. First, aluminum nitrate nonahydrate and sodium hydroxide solid reagents were accurately weighed according to a concentration of 500 mM, and a mixed solution was prepared using a fractional dissolution method. After preparation, a stir bar was added and the mixture was stirred at a constant speed (300 rpm) on a magnetic stirrer for half an hour. After the reaction was complete, it was allowed to stand for one hour, and the supernatant was collected and filtered to prepare an aluminum nitrate solution containing sodium ions, which facilitates the formation of aluminum hydroxide precipitate in the later stage. In the laser painting step, the prepared ink was transferred to the chamber of the PDMS using a pipette, thereby forming a dense aluminum hydroxide structure under photothermal conditions. During the ink sealing process, a polydimethylsiloxane (PDMS) annular frame with a height of about 1 mm was adhered to the platinum-plated glass substrate as a reservoir. The aluminum nitrate ink solution was placed in the PDMS reservoir, and then sealed by covering it with a second PDMS component to prevent solvent evaporation during laser printing.

[0079] To achieve high-precision, high-quality structural color laser printing technology, the following laser processing system was built, such as... Figure 3 As shown, the laser processing system includes a half-wave plate, a Glan Taylor prism, an acousto-optic modulator, a pinhole, a galvanometer, a first lens, a second lens, and a light-emitting diode (LED). The 532 nm laser power is initially controlled by the combination of the half-wave plate and the Glan Taylor prism. The acousto-optic modulator is used for further fine-tuning of the laser power. The pinhole is used for spatial filtering of the laser beam. The galvanometer is used for beam deflection. The first and second lenses deflect the beam to the entrance pupil of the objective lens. The LED is used for illumination during camera observation during the processing.

[0080] Specifically, the processing substrate, scanning speed, and processing power are three important parameters in the laser processing of samples. Processing was performed on glass substrates, platinum-plated substrates, silicon-plated substrates, and silicon dioxide substrates, respectively. It was found that the processed lines on the platinum-plated substrate were dense and did not peel off, and the cost was lower compared to silicon-plated and silicon dioxide substrates. At the same time, the aluminum hydroxide structure generated by processing on a 30 nm to 50 nm thick platinum-plated substrate with a 532 nm continuous laser was the most stable. For single-point processing of aluminum hydroxide, controlling the laser processing power to 2.7 mW to 3.9 mW and the exposure time to 10 ms to 10 s can produce dots with diameters of 0.8 μm to 4.2 μm. For line processing of aluminum hydroxide, controlling the laser processing power to 3 mW to 3.9 mW and the scanning speed to 10 μm / s to 60 μm / s can generate dense lines. For processing small blocks of aluminum hydroxide, controlling the processing power to 2.35 mW to 3.9 mW, the single-point spacing to 400 nm to 600 nm, and the single-point exposure time to 20 μs to 60 μs can produce color blocks with thicknesses of 250 nm to 650 nm. Figure 4a , Figure 4b This demonstrates the quantitative controllability of the generated structure during laser processing. By controlling the laser power and exposure time, quantitative controllability of the single-point diameter and the thickness of the color block was achieved, respectively. Figure 4a The relationship between exposure time and single-point diameter monotonically increasing at laser processing powers of 3.0 mW and 3.35 mW is described. Figure 4b The relationship between single-point exposure time (20 μs, 25 μs, 30 μs, 35 μs, 40 μs, 45 μs, 50 μs, 55 μs, and 60 μs) and monotonically increasing color patch thickness is described at laser processing powers of 3.0 mW and 3.35 mW. Based on... Figure 4a and Figure 4b The correspondence between processing parameters and generated structures was established. Combined with the phenomenon of coherent superposition of light after reflection from the upper and lower surfaces of the aluminum hydroxide color block, the laser power was controlled to increase sequentially from 3.0 mW, 3.1 mW, 3.2 mW, 3.3 mW, 3.4 mW, 3.5 mW, 3.6 mW, and 3.7 mW, ultimately successfully processing structures as shown in the figure. Figure 5 The image shows a large 8×7 color block containing multiple colors such as blue, red, purple, orange, yellow, and cyan.

[0081] Specifically, the segmentation process includes: first performing grayscale processing on the image to be processed to obtain a grayscale histogram of the entire image; then dividing the entire image into two regions, namely a black region and a white region, through global threshold segmentation; wherein the black region is the target object region and the white region is the background region.

[0082] Specifically, the slicing process includes: during processing, it is usually necessary to control the laser beam's movement in three-dimensional space to achieve point-to-point processing. However, traditional two-dimensional images only contain planar information and cannot perform high-precision path planning; therefore, it is necessary to convert the two-dimensional image into a three-dimensional coordinate file that the controller can recognize. During the slicing process, the sliced ​​file can be optimized by adjusting the image scaling and the single-point exposure spacing. Considering the relationship between the time required for laser processing and the single-point exposure diameter, the single-point spacing of the slices in this invention is set to 500 nm, which saves processing time without affecting the pattern structure.

[0083] Laser painting: By focusing 532 nm continuous light onto a glass heat-absorbing substrate coated with 50 nm platinum, and combining this with point cloud data formed by pattern segmentation and slicing, two-dimensional patterns can be painted by controlling specific single-point exposure times (commonly between 10 μs and 50 μs) and processing power (commonly between 3 mW and 3.9 mW). To achieve better coloring, multiple processing steps are usually performed first to find the correspondence between processing parameters and colors under the same conditions. Simultaneously, when processing multi-color patterns, it is crucial to ensure that the displacement stage does not move; otherwise, the processed patterns will not overlap. Figure 6 As shown, Figure 6 The study selected JPG photos of flowers, processed the original images to generate corresponding point cloud files for different colored parts, and then formed specific colors through appropriate processing parameters, thereby preparing multicolor structural color devices.

[0084] like Figure 7As shown, to achieve effective information encryption and label anti-counterfeiting, a solution etching method is employed: the aluminum hydroxide surface is etched by immersion in a solution, revealing the hidden information. In one embodiment, a 500 mM zirconium oxynitrate solid reagent is precisely weighed and fully dissolved in deionized water to form a zirconium oxynitrate solution. This solution is then applied dropwise to a platinum-coated glass slide (i.e., a glass substrate) using a pipette. A high-temperature field is created on the surface of the platinum-coated glass slide using a laser to induce the precipitation of zirconium oxide. The movement of a galvanometer is controlled by reading the corresponding QR code point cloud file via a computer to process and form a zirconium oxide QR code pattern. Next, a thin film of aluminum hydroxide is applied to the zirconium oxide QR code pattern at a power of 3.35 mW with a single-point exposure time of 30 μs, thus concealing the QR code information and encrypting it. During post-processing, a 0.1 mol / L sodium hydroxide solution is added to quickly remove the aluminum hydroxide layer, exposing the underlying QR code information. Considering the varying resistance of different materials to alkaline corrosion, this method can be repeated multiple times. The emergence of this technology can greatly reduce the difficulty of producing anti-counterfeiting labels, and its application in the commodity field can better protect the rights and interests of merchants and consumers.

[0085] In laser-printed aluminum hydroxide structures and anti-counterfeiting applications, a series of treatments are required before platinum plating on the substrate's cover glass to ensure easier processing and prevent peeling. First, the glass cover glass is carefully wiped clean with an ethanol and isopropanol solution to remove surface impurities. Then, it is placed in an oven at 150°C for one hour, and after drying and cooling, it is treated in a plasma processing machine for 8 minutes to enhance surface adhesion. Further exploration of more substrates, such as ceramic materials and high-end liquor bottle caps, will expand the commercial application of this technology.

[0086] It should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions of each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A laser-based color painting method for aluminum-based materials and its anti-counterfeiting features, characterized in that... include: Step 1: Transfer the prepared ink onto the glass substrate using a pipette, and fix the glass substrate to the laser processing system. The ink is composed of aluminum nitrate and sodium hydroxide. Step 2: Focus the laser beam onto the interface between the ink and the glass substrate, and induce the growth of aluminum hydroxide micro / nano structures on the surface of the glass substrate through the local photothermal effect of the laser. Step 3: The image to be processed is segmented and sliced ​​sequentially to generate point cloud data; Step 4: Based on the point cloud data, control the focused laser beam to perform two-dimensional patterning scanning. During the scanning process, control the laser exposure time and laser power to quantitatively control the geometric parameters of the aluminum hydroxide microstructure, and finally quantitatively regulate the structural color of the aluminum hydroxide microstructure. Step 5: Remove the glass substrate from the laser processing system, rinse it with deionized water and dry it with nitrogen gas to finally achieve the color painting of the aluminum-based structural color; Step Six: Use solution etching method to encrypt the painted information and prevent label counterfeiting.

2. The laser painting method based on aluminum-based materials and its anti-counterfeiting method according to claim 1, characterized in that, The specific preparation method of the ink is as follows: Weigh aluminum nitrate nonahydrate and sodium hydroxide solid reagents precisely according to a 500 mM molar concentration. The mixed solution was prepared using a fractional dissolution method; Add a stir bar and stir at a constant speed on a magnetic stirrer for half an hour. After the reaction is complete, let it stand for one hour, take the supernatant and filter it to prepare an aluminum nitrate solution containing sodium ions.

3. The laser painting method based on aluminum-based materials and its anti-counterfeiting method according to claim 1, characterized in that, The laser processing system includes a half-wave plate, a Glan Taylor prism, an acousto-optic modulator, a pinhole, a galvanometer, a first lens, a second lens, and a light-emitting diode (LED). The laser power is initially controlled by the combination of the half-wave plate and the Glan Taylor prism. The acousto-optic modulator is used for further fine-tuning of the laser power. The pinhole is used for spatial filtering of the laser beam. The galvanometer is used for beam deflection. The first and second lenses deflect the beam to the entrance pupil of the objective lens. The LED is used for illumination during camera observation during the processing.

4. The laser painting method based on aluminum-based materials and its anti-counterfeiting method according to claim 1, characterized in that, The segmentation process includes: first, performing grayscale processing on the image to be processed to obtain a grayscale histogram of the entire image; then, using global threshold segmentation, dividing the entire image into two regions, namely a black region and a white region; wherein the black region is the target object region and the white region is the background region.

5. The laser painting method based on aluminum-based materials and its anti-counterfeiting method according to claim 1, characterized in that, The slicing process includes optimizing the sliced ​​file by adjusting the image scaling and the single-point exposure spacing; wherein the single-point spacing of the slices is set to 500 nm.

6. The laser painting method based on aluminum-based materials and its anti-counterfeiting method according to claim 1, characterized in that, The method of using solution etching to encrypt colored information and prevent label counterfeiting specifically includes: adding zirconium oxynitrate solution to the surface of a glass substrate, focusing a laser on the surface of the glass substrate to generate a local high-temperature field that induces the zirconium oxynitrate solution to form a zirconium oxide QR code pattern, and then adding ink to the surface of the zirconium oxide QR code pattern to process an aluminum hydroxide pattern on the surface of the zirconium oxide QR code pattern, thus hiding the zirconium oxide QR code pattern inside and encrypting the information.

7. A laser-based color painting system and its anti-counterfeiting system based on aluminum-based materials, characterized in that, include: Glass substrate fixing module: used to transfer the prepared ink onto the glass substrate using a pipette and fix the glass substrate to the laser processing system, wherein the ink is composed of aluminum nitrate and sodium hydroxide; Structure forming module: used to focus the laser beam to the interface between the ink and the glass substrate, and induce the growth of aluminum hydroxide micro-nano structures on the substrate surface through the local photothermal effect of the laser. The image processing module is used to segment and slice the image to be processed, and finally generate point cloud data. The color painting quantitative control module is used to control the focused laser beam to perform two-dimensional pattern scanning based on point cloud data. During the scanning process, the laser exposure time and laser power are controlled to quantitatively control the geometric parameters of the aluminum hydroxide microstructure, and finally quantitatively control the structural color of the aluminum hydroxide microstructure. The color painting module is used to remove the glass substrate from the laser processing system, and then use deionized water for subsequent rinsing and nitrogen drying to finally achieve the color painting of the aluminum-based structural color. The anti-counterfeiting module is used to encrypt the painted information and prevent the label from being counterfeited by using a solution etching method.

8. The laser painting and anti-counterfeiting system based on aluminum-based materials according to claim 7, characterized in that, The specific preparation method of the ink is as follows: Weigh aluminum nitrate nonahydrate and sodium hydroxide solid reagents precisely according to a 500 mM molar concentration. The mixed solution was prepared using a fractional dissolution method; Add a stir bar and stir at a constant speed on a magnetic stirrer for half an hour. After the reaction is complete, let it stand for one hour, take the supernatant and filter it to prepare an aluminum nitrate solution containing sodium ions.

9. The laser painting and anti-counterfeiting system based on aluminum-based materials according to claim 7, characterized in that, The laser processing system includes a half-wave plate, a Glan Taylor prism, an acousto-optic modulator, a pinhole, a galvanometer, a first lens, a second lens, and a light-emitting diode (LED). The laser power is initially controlled by the combination of the half-wave plate and the Glan Taylor prism. The acousto-optic modulator is used for further fine-tuning of the laser power. The pinhole is used for spatial filtering of the laser beam. The galvanometer is used for beam deflection. The first and second lenses deflect the beam to the entrance pupil of the objective lens. The LED is used for illumination during camera observation during the processing.

10. The laser painting and anti-counterfeiting system based on aluminum-based materials according to claim 7, characterized in that, The image processing module further includes a segmentation module, which is used to first perform grayscale processing on the image to be processed to obtain a grayscale histogram of the entire image, and then divide the entire image into two regions, namely a black region and a white region, through global threshold segmentation. The black area represents the target object area, and the white area represents the background area.

Images