Direct reflective optical anti-counterfeiting element and preparation method thereof

Abstract

The invention discloses a direct reflective optical anti-counterfeiting element and a preparation method thereof.The optical anti-counterfeiting element comprises a base film material layer, a three-dimensional microstructure array layer, a metal layer, an adhesive layer, a paper layer and a back coating, and the base film material layer, the three-dimensional microstructure array layer, the metal layer, the adhesive layer, the paper layer and the back coating are sequentially attached from top to bottom; the three-dimensional microstructure array layer comprises a micro Fresnel lens array and a micro image-text array, a micro Fresnel lens adopts a concentric ring structure, and on the premise that the effective refraction performance of each area of the original lens is reserved, each ring belt should inherit the curvature characteristics of the corresponding area. The base membrane material layer is used as a basic supporting layer, so that good mechanical property and thermal stability are provided, and a reliable carrier is provided for subsequent microstructure copying and functional layer coating. Secondly, the introduction of the three-dimensional microstructure array layer is a core assembly for realizing an optical anti-counterfeiting function.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical anti-counterfeiting, and in particular relates to a direct reflective optical anti-counterfeiting element and a preparation method thereof. Background Art

[0002] Microlens imaging technology, based on the ability of microlens arrays to refract and focus light, can form three-dimensional images on the packaging surface. By designing specific microlenses and micro-graphic arrays, this technology allows observers to see three-dimensional patterns or text from different angles, greatly enhancing the visual appeal and anti-counterfeiting performance of the packaging. For example, patents CN104191860B, CN206623504U, and CN102991860A all utilize microlens arrays and variations in the thickness of their transparent layers to achieve a 3D display effect visible to the naked eye, adding decorative and anti-counterfeiting properties to the packaging. Furthermore, microlens imaging can also achieve dynamic effects, such as animation or gradient effects. When the observer moves the packaging, the pattern changes accordingly, which increases the difficulty of replicating traditional printing technologies and further enhances anti-counterfeiting capabilities.

[0003] However, despite the significant advantages of microlens imaging technology, it also faces some challenges and limitations in practical applications. First, during the manufacturing process, the preparation of microlens anti-counterfeiting elements requires the design and production of microlenses and micro-image arrays in sequence, which places high demands on equipment and processes, resulting in relatively high manufacturing costs. Secondly, the design of microlens anti-counterfeiting must take into account the matching between the type and thickness of the product base film and the imaging focal length. Since different packaging materials and thicknesses will affect the anti-counterfeiting effect of the microlens, it is not easy to achieve the best optical effect. Especially when dealing with microlens arrays with complex structures, if the base film is not selected properly or the thickness is not accurately controlled, it may cause blurred images or even fail to form the expected three-dimensional effect. Summary of the Invention

[0004] In order to overcome the shortcomings of the existing technology, the purpose of the present invention is to provide a directly reflective optical anti-counterfeiting element and a preparation method thereof. By optimizing the design and manufacturing process of the microlens and micro-image array, an optical anti-counterfeiting element with one-time molding and excellent visual effect is provided, which simplifies the preparation process, reduces production costs, and allows clear and bright three-dimensional images to be observed with the naked eye.

[0005] To solve the above problems, the technical solution adopted by the present invention is as follows: a directly reflective optical anti-counterfeiting element, comprising: a base film material layer, a three-dimensional microstructure array layer, a metal layer, an adhesive layer, a paper layer and a back coating layer. The base film material layer, the three-dimensional microstructure array layer, the metal layer, the adhesive layer, the paper layer and the back coating layer are sequentially bonded from top to bottom. The three-dimensional microstructure array layer includes a micro Fresnel lens array and a micro graphic array. The micro Fresnel lens adopts a concentric ring structure. On the premise of retaining the effective refractive performance of each area of ​​the original lens, each ring band should inherit the curvature characteristics of the corresponding area.

[0006] Compared to the prior art, the present invention has the following advantages: Prior to photolithography, the present invention generates a preset three-dimensional microstructure array by superimposing and nesting a lens array with an image array. This allows for a single-shot optical anti-counterfeiting film with three-dimensional images that can be observed with the naked eye, eliminating the need to consider the effects of alignment accuracy and base film thickness on imaging. Furthermore, the micro-image array is overlapped and nested within the micro-Fresnel lens array, retaining the image information portion of the micro-image array to form a light reflection area. This allows the imaged images to appear clear and bright when observed with the naked eye, enhancing the three-dimensional perception of the optical anti-counterfeiting element. Furthermore, the thickness and weight of the lens are reduced, enabling a higher lens curvature to be achieved without increasing the thickness of the photoresist. Furthermore, the thinner lens structure reduces the distance light travels within the lens, reducing light energy loss.

[0007] The present invention also provides a preparation method, comprising the above-mentioned anti-counterfeiting element, which at least has all the beneficial effects that can be brought about by the above-mentioned anti-counterfeiting element.

[0008] The present invention also provides a preparation method, comprising the above-mentioned anti-counterfeiting element, comprising the following steps:

[0009] S1: manufacturing the three-dimensional microstructure array layer, spatially overlapping the microFresnel lens array and the micrographic array so that the fixed points of the microFresnel lens array and the micrographic array coincide with each other to obtain the three-dimensional microstructure array layer, nesting the micrographic array in the microFresnel lens array, and generating a corresponding photolithography file;

[0010] S2: preparing a resin master, importing the photolithography file obtained in step S1 into a photolithography machine and performing exposure, transferring the three-dimensional microstructure array layer to the glue layer of the photolithography glass, and revealing the three-dimensional microstructure array layer structure of the exposed photolithography glass, placing a resin film on the photolithography glass in a panelizing machine, adding resin material and applying a certain pressure to tightly adhere the resin film to the photolithography glass, and then fixing the structural shape of the three-dimensional microstructure array layer, and peeling off to obtain the resin film master;

[0011] S3: preparing a metal nickel plate, depositing a layer of metal silver on the resin film master obtained in step S2 by a silver mirror reaction, placing the resin master with the metal silver as a cathode in an electrolytic cell containing an electrolyte containing nickel ions, and depositing nickel on the cathode by electroplating to obtain the metal nickel plate having the three-dimensional microstructure array layer;

[0012] S4: preparing an optical anti-counterfeiting film, selecting a base film material, and replicating the three-dimensional microstructure array layer in step S3 onto a base film surface of the base film material having a thickness of 15 to 50 μm using an embossing and replicating unit on a rotary embossing device to obtain the optical anti-counterfeiting film;

[0013] S5: Vapor-depositing a reflective metal layer: Vacuum-depositing a reflective metal layer on the surface of the three-dimensional microstructure array layer of the optical anti-counterfeiting film obtained in step S4. The reflective metal layer can be made of any one of Al, Au, Ag, Cu, Cr, Sn, and Pt, or an alloy of two or more thereof.

[0014] S6: Laminating paper to produce optical anti-counterfeiting paper, laminating the optical anti-counterfeiting film provided with the metal layer to paper of corresponding specifications by glue to obtain the optical anti-counterfeiting paper.

[0015] In the above-mentioned preparation method, the resin material in step S2 is a UV-curable resin material, and the resin film is made of polyethylene terephthalate with a thickness of 100 to 300 μm.

[0016] In the above-mentioned preparation method, the resin film in step S2 is made of a polyethylene terephthalate film with a thickness of 188 μm.

[0017] In the above-mentioned preparation method, the step S2 fixes the structural shape of the three-dimensional microstructure array layer by ultraviolet light irradiation.

[0018] In the above-mentioned preparation method, the rotary embossing equipment described in step S4 adopts the ultraviolet light curing embossing method to evenly coat the ultraviolet light curing coating on one side surface of the base film material. The embossing replication unit, under the action of the pressing roller and ultraviolet light, makes the varnish layer coated on the base film adhere to the metal nickel plate, and after curing, the replication, transfer and curing of the three-dimensional microstructure array layer are completed to obtain the optical anti-counterfeiting film.

[0019] In the above-mentioned preparation method, during the embossing process of step S4, pressure needs to be applied so that the UV-curable varnish can fully fill the structural grooves of the nickel plate, so that the three-dimensional microstructure array layer is transferred with integrity.

[0020] The preparation method, in the embossing process of step S4, the base film material adopts PET chemical base film with pre-coating.

[0021] The preparation method, in step S4, the rotary embossing equipment adopts hot stamping method, under the action of high temperature, the surface of the base film material thermoplastic coating is softened and extruded into the groove of the three-dimensional microstructure array layer, after cooling and shaping, the optical security film is obtained.

[0022] The preparation method, in step S4, the thermoplastic coating adopts peelable transfer coating or composite coating. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 A direct reflection optical security element and its preparation method steps are shown in the figure.

[0024] Figure 2 The layered structure of the optical security element is shown in the figure.

[0025] Figure 3 The visual effect of the optical security element is shown in the figure.

[0026] Figure 4 The partial top view of the microstructure array of the optical security element is shown in the figure (the gray part is the direct reflection area)

[0027] Explanation of reference numerals: 01 base film material layer, 02 three-dimensional microstructure array layer, 03 metal layer, 04 adhesive layer, 05 paper layer, 06 back coating layer. DETAILED DESCRIPTION

[0028] The embodiments of the present application are described in detail below, with reference to the accompanying drawings Figures 1 to 4The embodiment of the present application provides a kind of direct reflective optical security element and its preparation method, and optical security element includes: base film material layer 01, stereoscopic microstructure array layer 02, metal layer 03, adhesive layer 04, paper layer 05 and back coating layer 06, base film material layer 01, stereoscopic microstructure array layer 02, metal layer 03, adhesive layer 04, paper layer 05 and back coating layer 06 are sequentially adhered from top to bottom, stereoscopic microstructure array layer 02 includes micro-fresnel lens array and micro-text array, micro-fresnel lens adopts concentric ring structure, under the premise of keeping the effective refractive performance of each area of original lens, each ring band should inherit the curvature characteristics of corresponding area.By taking base film material layer 01 as basic support layer, good mechanical property and thermal stability are provided, which provides reliable carrier for subsequent microstructure replication and functional layer coating.Secondly, the introduction of stereoscopic microstructure array layer 02 is the core component for realizing optical security function, and the micro-fresnel lens array contained therein has the ability to focus light, and the micro-text array can present specific visual information, and the combination of the two can realize multiple optical effects such as dynamic optical color change, image magnification, three-dimensional display, greatly enhancing the intuitiveness and uniqueness of anti-counterfeiting identification.Further, micro-fresnel lens adopts concentric ring structure design, under the premise of keeping the effective refractive performance of original lens, each ring band inherits the curvature characteristics of corresponding area of original lens.This design not only effectively reduces the thickness and weight of traditional lens, but also maintains good optical focusing ability, thereby realizing miniaturization and integration application without sacrificing optical performance.In addition, metal layer 03 (such as aluminum, silver, etc.) is deposited on the surface of stereoscopic microstructure by vacuum evaporation method, which enhances the light reflection efficiency, so that the observer can clearly see the dynamic optical pattern at different angles, improving the visual recognition degree.Adhesive layer 04 is used to firmly adhere the optical security film to paper layer 05, to ensure that the product is not easy to fall off or damaged during use;Back coating layer 06 plays a role in protecting the overall structure and enhancing durability.

[0029] The present application generates a preset stereoscopic microstructure array by superimposed nesting of lens array and text array before photolithography, and only one processing is needed to obtain an optical security film that can be observed by naked eye, so that the influence of alignment accuracy and base film thickness on imaging does not need to be considered.Meanwhile, the micro-text array is overlapped and nested in the micro-fresnel lens array, the text information part of the micro-text array is formed as light reflection area, so that the imaging text observed by naked eye presents clear and bright visual effect, enhancing the stereoscopic feeling of optical security element.Further, the thickness and weight of lens are reduced, higher lens curvature can be realized without increasing the thickness of photoresist, and thinner lens structure reduces the propagation distance of light in lens, reducing the loss of light energy.

[0030] Furthermore, the present invention also provides a method for preparing an optical anti-counterfeiting element, which specifically includes the following steps: S1: making a three-dimensional microstructure array layer 02, overlapping the micro-Fresnel lens array and the micro-graphic array in a spatial three-dimensional structure, so that the fixed points of the micro-Fresnel lens array and the micro-graphic array coincide with each other, to obtain a three-dimensional microstructure array layer 02, nesting the micro-graphic array in the micro-Fresnel lens array, and generating a corresponding photolithography file; S2: making a resin master, importing the photolithography file obtained in step S1 into a photolithography machine and exposing it, transferring the three-dimensional microstructure array layer 02 to the glue layer of the photolithography glass, and exposing the exposed The three-dimensional microstructure array layer 02 structure of the photolithographic glass is revealed. A resin film is placed on the photolithographic glass in a panelizing machine. Resin material is added and a certain pressure is applied to tightly adhere the resin film to the photolithographic glass. The shape of the three-dimensional microstructure array layer 02 structure is then fixed and peeled off to obtain a resin film master. S3: A metal nickel plate is prepared. A layer of metallic silver is deposited on the resin film master obtained in step S2 through a silver mirror reaction. The resin master with the metallic silver attached is placed as a cathode in an electrolytic cell containing an electrolyte containing nickel ions. Nickel is deposited on the cathode by electroplating to obtain a metal nickel plate having a three-dimensional microstructure array layer 02.

[0031] S4: Making an optical anti-counterfeiting film, selecting a base film material layer 01, and using an imprinting replication unit on a rotary imprinting device to copy the three-dimensional microstructure array layer 02 in step S3 to the base film surface of the base film material layer 01 with a thickness of 15 to 50 μm to obtain an optical anti-counterfeiting film; S5: Vapor-depositing a reflective metal layer 03, providing a reflective metal layer 03 on the surface of the three-dimensional microstructure array layer 02 of the optical anti-counterfeiting film obtained in step S4 by vacuum evaporation, and the reflective metal layer 03 can be made of any one of Al, Au, Ag, Cu, Cr, Sn, and Pt, or an alloy composed of two or more thereof; S6: Laminating paper 05 to make optical anti-counterfeiting paper, pasting the optical anti-counterfeiting film provided with the metal layer 03 to paper 05 of corresponding specifications with glue to obtain optical anti-counterfeiting paper. In step S1, the micro-Fresnel lens array and the micro-graphic array are spatially overlapped, so that the two structures form a unified three-dimensional microstructure array layer 02 with fixed points coinciding. This enhances the layering and complexity of the optical pattern, and strengthens the reliability and aesthetics of anti-counterfeiting identification. In step S2, a photolithography process is used to transfer the designed photolithography file to the adhesive layer of the photolithography glass. By closely bonding the resin film to the photolithography glass and then subjecting it to UV curing, a resin master with a high-precision microstructure is obtained. This step ensures the consistency and fidelity of the structure during subsequent replication and is a key step in achieving high-quality optical microstructure replication. In step S3, a metal nickel plate is prepared on the resin master through an electroplating process. This metal nickel plate has excellent mechanical strength and wear resistance, making it suitable for large-scale continuous production, greatly improving production efficiency and reducing manufacturing costs. In step S4, the three-dimensional microstructure array layer 02 is replicated onto the base film material layer 01 using a rotary embossing device to form an optical anti-counterfeiting film. This process uses UV curing or hot pressing technology to ensure complete replication of the microstructure while preventing structural deformation or collapse, thereby improving the product's optical performance and consistency. Step S5 deposits a reflective metal layer 03 on the surface of the optical security film through vacuum evaporation, further enhancing the structure's ability to reflect incident light. This allows the observer to perceive distinct dynamic optical changes at different viewing angles, improving the intuitiveness and security of anti-counterfeiting identification. Step S6 glues the optical security film with the metal layer 03 to the paper layer 05, completing the final preparation of the optical security paper. This process is simple to operate, highly adaptable, and facilitates large-scale promotion and application.

[0032] Furthermore, the resin material in step S2 is a UV-curable resin material, and the resin film is made of polyethylene terephthalate with a thickness of 100 to 300 μm. Preferably, the resin film in step S2 is made of polyethylene terephthalate film with a thickness of 188 μm. PET material of this thickness is easy to adhere to the photoresist layer and can fully contact the photolithographic pattern after applying a certain pressure, reducing the generation of bubbles and gaps, thereby improving the quality of the master. It is also relatively easy to peel off after curing, without causing structural damage, which is conducive to the repeated use and repeated replication of the master. Furthermore, step S2 fixes the structural shape of the three-dimensional microstructure array layer 02 by ultraviolet light irradiation. Ultraviolet light irradiation is an efficient and controllable curing method, especially suitable for UV-curing resin materials. By shaping the resin structure in this way, the structural curing can be completed in a short time, significantly shortening the master production cycle and improving production efficiency. More importantly, ultraviolet light irradiation can achieve non-contact curing, avoiding the structural deformation or local shrinkage problems that may be caused by traditional heating or chemical curing methods, thereby ensuring the geometric accuracy and optical performance of the three-dimensional microstructure array layer 02. This curing method can also flexibly control the curing depth and hardness by adjusting the light intensity and time to meet the replication requirements of different structural complexities. Furthermore, the rotary wheel imprinting equipment in step S4 adopts the method of ultraviolet light curing imprinting to evenly coat the ultraviolet light curing coating on one side of the base film material layer 01. The embossing and replication unit, under the action of the pressure roller and ultraviolet light, makes the varnish layer coated on the base film and the metal nickel plate adhere and cure, completing the replication transfer and curing of the three-dimensional microstructure array layer 02 to obtain an optical anti-counterfeiting film. During this imprinting process, pressure needs to be applied so that the ultraviolet light curing varnish can fully fill the structural grooves of the nickel plate, so that the transfer of the three-dimensional microstructure array layer 02 is complete. This method, through the collaboration of an embossing unit and a metal plate roller, achieves nanometer-level structural replication, ensuring perfect reproduction of the details of the micro-Fresnel lens and micro-image array. Furthermore, UV irradiation precisely controls the curing area, avoiding issues such as blurred edges and structural connections, and improving pattern clarity. Appropriate pressure forces the UV-curable varnish to fully flow into the microstructure grooves on the nickel plate, filling all subtle contours and ensuring the integrity and consistency of the replicated structure. Insufficient pressure may prevent the varnish from completely filling the grooves, resulting in missing or broken structures and affecting optical performance. Excessive pressure may cause the base film to stretch, deform, or collapse. The base film material layer 01 in this process is a pre-coated PET base film. Alternatively, the rotary embossing equipment in step S4 can also be used for hot pressing replication. The high temperature softens the thermoplastic coating on the surface of the base film material layer 01 and squeezes it into the grooves of the three-dimensional microstructure array layer 02. After cooling and finalizing, the optical anti-counterfeiting film is obtained. This method eliminates the need for a UV light source, simplifying equipment configuration and reducing energy consumption and maintenance costs.At the same time, hot pressing replication is applicable to a variety of thermoplastic materials and has strong process adaptability. By adjusting the temperature and pressure parameters, key parameters such as the aspect ratio and roughness of the structure can be finely controlled. In addition, the physical filling mechanism during the hot pressing replication process helps to improve the continuity and consistency of the structure, especially showing obvious advantages when replicating complex three-dimensional structures. The cooled structure has good thermal stability and mechanical strength, and can withstand the various environmental tests of subsequent processing and actual use. In this process, the thermoplastic coating adopts a peelable transfer coating or composite coating.

[0033] An embodiment of the present invention comprises: converting preset graphic information into a micro-graphic array via software, and simultaneously producing a micro-Fresnel lens array based on designed micro-Fresnel lens parameters. The micro-graphic array and the micro-Fresnel lens array are combined by superimposing and computing the resulting three-dimensional microstructure, wherein the structural morphologies and central curvatures of the two are combined to form a three-dimensional microstructure. During the overlapping process, the three-dimensional microstructure retains a portion of the graphic information of the micro-graphic array. A photolithography machine is used to expose and develop the three-dimensional microstructure onto a photosensitive adhesive layer on a photolithography glass, thereby forming a three-dimensional microstructure array on the photosensitive adhesive layer on the photolithography glass. A 188μm PET film is placed on the photolithography glass on a plate-forming machine, and plate-forming oil is squeezed into the film to tightly adhere to the photolithography glass by applying pressure. The film is cured by ultraviolet light and then peeled off to obtain a PET master film. After forming a silver layer on the PET master film, the film is placed in an electrolytic cell as a cathode, placed in an electrolyte containing nickel ions, and metallic nickel is deposited on the cathode PET master film by electroplating to form a metallic nickel plate having a three-dimensional microstructure array. A layer of UV-curing coating is evenly coated on the PET base film in the coating unit of the UV-curing imprinting equipment, and then the varnish layer coated on the base film is bonded to the metal nickel plate under the action of the pressure roller and UV light in the imprinting unit, and after curing, the microstructure is replicated, transferred and cured to obtain an optical anti-counterfeiting film; a reflective metal aluminum layer is provided on the surface of the micro-stereoscopic structure array layer 02 of the obtained optical anti-counterfeiting film by vacuum evaporation; the optical anti-counterfeiting film provided with the metal layer 03 is glued together with a paper 05 of a predetermined specification by glue to obtain an optical anti-counterfeiting paper.

[0034] It should be noted that in the description of the present invention, if there are any descriptions of directions, such as up, down, front, back, left, right, etc., the directions or positional relationships indicated are all based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed or operate in a specific direction, and cannot be understood as a limitation on the present invention.

[0035] In the description of the present application, the meaning of one or more is one or more, the meaning of multiple is two or more, greater than, less than, more than, etc. is understood as not including the number, above, below, within, etc. is understood as including the number. If there is a description of first or second, etc., it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or implicitly indicating the order of the indicated technical features.

[0036] In the description of the present application, unless otherwise expressly limited, the words such as setting, installing, connecting, etc. should be broadly understood, and those skilled in the art can reasonably determine the specific meaning of the above words in the present application in combination with the specific content of the technical scheme.

[0037] The above embodiments are only preferred embodiments of the present application, and cannot be used to limit the scope of protection of the present application. Any non-essential changes and substitutions made by those skilled in the art on the basis of the present application are within the scope of protection of the present application.

Claims

1. A directly reflective optical anti-counterfeiting element, characterized in that: include: A base film material layer (01), a three-dimensional microstructure array layer (02), a metal layer (03), an adhesive layer (04), a paper layer (05) and a back coating layer (06), wherein the base film material layer (01), the three-dimensional microstructure array layer (02), the metal layer (03), the adhesive layer (04), the paper layer (05) and the back coating layer (06) are sequentially bonded from top to bottom, wherein the three-dimensional microstructure array layer (02) comprises a micro-Fresnel lens array and a micro-graphic array, wherein the micro-Fresnel lens adopts a concentric ring structure, and under the premise of retaining the effective refractive performance of each area of ​​the original lens, each ring band should inherit the curvature characteristics of the corresponding area.

2. A preparation method, characterized in that: The anti-counterfeiting element according to claim 1 comprises the following steps: S1: manufacturing the three-dimensional microstructure array layer (02), overlapping the micro-Fresnel lens array and the micro-graphic array in a three-dimensional space structure, making the fixed points of the micro-Fresnel lens array and the micro-graphic array coincide with each other, so as to obtain the three-dimensional microstructure array layer (02), embedding the micro-graphic array in the micro-Fresnel lens array, and generating a corresponding photolithography file; S2: making a resin master, importing the photolithography file obtained in step S1 into a photolithography machine and performing exposure, transferring the three-dimensional microstructure array layer (02) to the glue layer of the photolithography glass, and revealing the structure of the three-dimensional microstructure array layer (02) of the exposed photolithography glass, placing a resin film on the photolithography glass in a panelizing machine, adding resin material and applying a certain pressure to make the resin film and the photolithography glass closely adhere, and then fixing the structural shape of the three-dimensional microstructure array layer (02), and peeling off to obtain the resin film master; S3: preparing a metal nickel plate, depositing a layer of metal silver on the resin film master obtained in step S2 by a silver mirror reaction, placing the resin master with the metal silver attached as a cathode in an electrolytic cell, wherein the electrolytic cell contains an electrolyte containing nickel ions, and depositing nickel on the cathode by electroplating to obtain the metal nickel plate having the three-dimensional microstructure array layer (02); S4: manufacturing an optical anti-counterfeiting film, selecting a base film material layer (01), and replicating the three-dimensional microstructure array layer (02) in step S3 to a base film surface of the base film material layer (01) with a thickness of 15 to 50 μm using an imprint replication unit on a rotary imprinting device to obtain the optical anti-counterfeiting film; S5: evaporating a reflective metal layer (03), providing a reflective metal layer (03) on the surface of the three-dimensional microstructure array layer (02) of the optical anti-counterfeiting film obtained in step S4 by vacuum evaporation, wherein the reflective metal layer (03) can be made of any one of Al, Au, Ag, Cu, Cr, Sn, and Pt, or an alloy composed of two or more thereof; S6: Laminating paper (05) to produce optical anti-counterfeiting paper, the optical anti-counterfeiting film provided with the metal layer (03) is glued together with paper (05) of corresponding specifications to obtain the optical anti-counterfeiting paper.

3. The preparation method according to claim 2, characterized in that The resin material in step S2 is a UV-curable resin material, and the resin film is made of polyethylene terephthalate with a thickness of 100 to 300 μm.

4. The preparation method according to claim 2, characterized in that The resin film in step S2 is made of a polyethylene terephthalate film with a thickness of 188 μm.

5. The preparation method according to claim 2, characterized in that The step S2 is a method of fixing the structural shape of the three-dimensional microstructure array layer (02) by irradiating it with ultraviolet light.

6. The preparation method according to claim 2, characterized in that The rotary embossing device described in step S4 adopts the method of ultraviolet light curing embossing to evenly coat the ultraviolet light curing coating on one side surface of the base film material layer (01). The embossing replication unit, under the action of the pressing roller and ultraviolet light, makes the varnish layer coated on the base film adhere to the metal nickel plate, and after curing, the replication, transfer and curing of the three-dimensional microstructure array layer (02) are completed to obtain the optical anti-counterfeiting film.

7. The preparation method according to claim 7, characterized in that During the stamping process of step S4, pressure needs to be applied so that the UV-curable varnish can fully fill the structural grooves of the nickel plate, so that the three-dimensional microstructure array layer (02) is transferred with integrity.

8. The preparation method according to claim 6, characterized in that The base film material layer (01) adopts a PET chemical base film with a pre-coating layer.

9. The preparation method according to claim 2, characterized in that In step S4, the rotary wheel imprinting device adopts a hot pressing replication method to soften the surface thermoplastic coating of the base film material layer (01) under the action of high temperature and squeeze it into the groove of the three-dimensional microstructure array layer (02), and obtain the optical anti-counterfeiting film after cooling and shaping.

10. The preparation method according to claim 9, characterized in that The thermoplastic coating in step S4 is a peelable transfer coating or a composite coating.

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