WO2016029692A1

WO2016029692A1 - Coloured dynamic stereoscopic moire image thin film based on micro printing and preparation method therefor

Info

Publication number: WO2016029692A1
Application number: PCT/CN2015/075480
Authority: WO
Inventors: 申溯; 朱昊枢; 朱鹏飞; 陈林森; 沈悦
Original assignee: 苏州大学; 苏州苏大维格光电科技股份有限公司
Priority date: 2014-08-27
Filing date: 2015-03-31
Publication date: 2016-03-03
Also published as: CN104191860A; CN104191860B

Abstract

Disclosed are a coloured dynamic stereoscopic moire image thin film based on micro printing and a preparation method therefor. A moire image thin film comprises a transparent base material layer, a micro lens array layer located at one side of the transparent base material layer and a micro pattern array layer located at the other side of the transparent base material layer. The micro lens array layer comprises several micro lenses arranged in an array. The micro pattern array layer comprises several sets of micro patterns arranged in an array and having different colours. The array arrangement of the micro lenses matches the array arrangement of the micro patterns. The moire image formed by the moire image thin film is characterized by being coloured, dynamic and stereoscopic. In any light environment, an observer can observe a coloured three-dimensional dynamic pattern without any special observation skill.

Description

Color dynamic stereoscopic moiré image film based on micro-printing and preparation method thereof

This application claims priority to Chinese Patent Application No. 201410428043.X, entitled "Micro-Printed Color Dynamic Stereo Moire Image Film and Its Preparation Method", filed on August 27, 2014, The entire contents of this application are incorporated herein by reference.

Technical field

The invention relates to the field of public optical visual security anti-counterfeiting technology, in particular to a micro-printing color dynamic stereoscopic moiré image film and a preparation method thereof.

Background technique

The optical anti-counterfeiting technologies mainly used in the prior art are classified into three categories: public anti-counterfeiting, professional anti-counterfeiting, and three-wire anti-counterfeiting. Public security is mainly used to form the main scene pattern, multi-channel and dynamic technology. Most professional anti-counterfeiting uses miniature images and text, which can be clearly distinguished by a high magnification magnifier with its own light source. The three-wire anti-counterfeiting is mainly a diffraction unit and various coding techniques. Among them, the public anti-counterfeiting technology is characterized by the fact that, under normal conditions, the naked eye or the sensory organ can directly identify features without using any instrument, and it is most easy to distinguish for the masses of the people, so it is especially important. It should have two basic elements: easy to identify and difficult to forge.

Among the public anti-counterfeiting technologies, the optical anti-counterfeiting technology currently used for labels, banknotes, credit cards, etc. mainly refers to Diffractive Optically Variable Image Devices (DOVID), which contains well-known holographic images, including pixel holograms developed in the later stage. Graphs, dot matrix holograms, and dynamic Mortu charts. Well-known products such as the French Hologram Industries company developed a DOVID technology in recent years, which is characterized by an image resolution of 600LPI, but the diffraction resolution of fine text and lines can reach 6000LPI, and the image brightness is high and the color is bright. The grating structure of the diffraction identification technique was invented by the Zurich laboratory of the Paul Scherrer Institute in Switzerland, with a grating period of less than 0.4 μm (modulo) The pressure holographic grating period is generally 1 μm). It is red when the image is viewed horizontally (or text); when the image is rotated 90° in the plane, dark green is observed. Machine-readable reliability is high and equipment prices are low. However, with the wide application of holography in the fields of ticket, trademark, packaging, etc., many manufacturers have the ability to produce holographic products, which makes laser holography into a crisis of trust.

Therefore, there is an urgent need to find a new generation of mass technology that meets high technology, low cost, easy to identify, and arbitrable. For example, in the fourth-generation laser combined hologram technology, tens or even hundreds of different two-dimensional images are recorded by tens or even hundreds of exposures, and the various aspects of the three-dimensional object and the changes with time are recorded. That is, the hologram can not only record and reproduce the three-dimensional (X, Y, Z) characteristics of the object, but also record and reproduce the change of the three-dimensional object with time (T). The production of such a hologram has no limitation on the object, and it is necessary to record two or even hundreds of frames of two-dimensional images, so that the number of exposures is several tens or even hundreds of times that of ordinary holography, which requires special instruments and more elaborate processes. The process can be achieved. In addition, the G-switch technology of Australian SecurencyPTY Company makes it possible to observe a color from one direction by making a special optical layer, and to observe the complementary color of the color from the orthogonal direction, without special training and instruments. It can be identified in a simple way in just one second to several seconds. In addition, people have also invented the safety line and its window opening technology to further improve the technical threshold, which is a linear mark made of a working film material.

Another class of compelling next-generation technologies is the Moiré amplification technology that combines a microlens array (MLA) with a micropattern array (MPA). Moiré amplification involves a phenomenon that can occur when observing an array of the same micropattern from a microlens array having substantially the same periodic dimension, i.e., in the form of an enlarged or rotated form of the micropattern. The basic principle of the Moir amplification phenomenon is M.C.Hutley, R.Hunt, R.F. Stevens and P.Savander, Pure Appl. Opt. 3 (1994), pp. 133-142 is described. A safety device that combines a hemispherical micro-convex lens array with a micro-pattern array is first proposed in U.S. Patent No. 5,712,731. The micro-pattern is near the back focal plane of the micro-convex lens, and the human eye can see the magnified image of the micro-pattern on the convex side of the micro-lens. The micro-convex lens has a diameter of 50-250 micrometers, and the micro-pattern array is obtained by gravure printing. The minimum resolution is 5 microns. In order to overcome the drawbacks of the above-mentioned patents which are disadvantageous for the fabrication of ultra-thin (thickness less than 50 micron) devices, RASteenblik et al. further expand the fabrication according to the micro-optics principle described above in U.S. Patent No. 2005/0180020 Al and subsequent patent No. 2008/0037131 Al. The range of safety devices, such as micro-convex lens diameter reduced to 20 ~ 30 microns, focal length less than 50 microns, spacer layer thickness less than 50 microns, micro-pattern layer has a variety of complex arrangements, can be transparent, translucent, fluorescent, phosphorescent, Dyeing, light-changing pigments, etc., and proposed a number of structures based on the reflection mode of operation and the like. A predetermined curved Brava lattice structure is proposed in the Chinese patent security element (Application No. 200680048634.8). By designing the microlens array and the micro-pattern array and their arrangement and combination, a variety of visual effects can be realized: 1) micro-pattern magnification: the micro-pattern that is not visible in the original is enlarged to be directly observable by the naked eye; 2) orthogonal movement: ie along When shaking in a certain direction, the observed macro image moves in a direction perpendicular to it; 3) stereoscopic effect: the observed macro image has a stereoscopic effect that floats or sinks on the paper surface; 4) motion deformation: the observed macro image Changes in size, shape, etc. may also occur during the movement. Moir zoom technology can achieve the above several visual effects on micro-patterns separately, and can also realize the combination of the above several visual effects at the same time. As a first-line technology that is easily recognized by the naked eye, it cannot be digital imaging and scanning. Copying, copying, printing equipment, etc.

The application of a micro-convex lens array and a micro-pattern array to a security device is proposed in U.S. Patent No. 5,721, 273, US Patent Application Publication No. 2005/0180020 A1, and US 2008/0037131 A1. The micro-pattern array is obtained by gravure printing with a minimum resolution of 5 microns. The main production method is to apply a photoresist on a flexible film such as PET, and emboss a groove having a depth of several micrometers on the surface of the photoresist with a relief with a microtext, and fill the ink into the groove by a doctor blade method. So that the microtext displays the corresponding color. In the micro-text production method, the color of the image is obtained by filling the color ink in the groove, and the micro-text is single color, and cannot form a color display; the micro-text feature size is several micrometers, and the general printing ink particle is Dozens of micrometers, therefore, special-made nano-scale inks can be used as filling color inks; in order to make enough ink to be filled into the grooves, improve the contrast between the micro-text and the background, the groove depth will be greater than 3 microns . It is necessary to make a large aspect ratio metal embossing template, which improves the process difficulty in large-format dynamic image production.

Therefore, in view of the above technical problems, it is necessary to provide a micro-printing-based color dynamic stereoscopic moiré image film and a preparation method thereof.

Summary of the invention

In view of this, in order to solve the problems in the prior art, the present invention provides a micro-printing-based color dynamic stereoscopic moiré image film and a preparation method thereof.

In order to achieve the above objective, the technical solution provided by the embodiment of the present invention is as follows:

A micro-printing-based color dynamic stereoscopic moiré image film comprising a transparent substrate layer, a microlens array layer on one side of the transparent substrate layer, and micro on the other side of the transparent substrate layer a pattern array layer, the microlens array layer comprising a plurality of array-arranged microlenses, the micro-pattern array layer comprising a plurality of sets of micro-patterns arranged in an array and having different colors, the micro-lens array arrangement and micro-patterns The array arrangement matches.

As a further improvement of the present invention, the microlens array layer and the micropattern array layer are square arrays Column arrangement or hexagon array arrangement.

As a further improvement of the present invention, the micropattern in the micropattern array layer has an overall size of 10 μm to 100 μm and a line width of 1 μm to 20 μm.

As a further improvement of the present invention, the magnification of the moiré image film is:

The period ratio of the microlens array to the micro-pattern array is r, and the angle between them is θ.

As a further improvement of the present invention, when the period ratio r of the microlens array and the micropattern array is 1, the magnification of the moiré image film is:

As a further improvement of the present invention, the period of movement of the moiré image formed by the moiré image film is:

The period of the microlens array is a, the period of the micropattern array is b, the distance between the microlens array and the micropattern is h, and the angle of observation from the vertical direction is Ф.

Correspondingly, a method for preparing a color dynamic stereoscopic moiré image film based on micro-printing, the method comprising:

S1, providing a transparent substrate layer;

S2, preparing a microlens array layer on a side of the transparent substrate layer, the microlens array layer comprising a plurality of arrays Arranged microlenses;

S3, preparing a micro-pattern array layer on the other side of the transparent substrate layer, the micro-pattern array layer comprising a plurality of sets of micro-patterns arranged in an array and having different colors, the array arrangement of the micro-lenses and the array of micro-patterns The cloth matches.

As a further improvement of the present invention, the step S3 is specifically:

The metal mask is placed on the transparent substrate layer and aligned, and the metal mask comprises a plurality of arrayed hollow micro-pattern structures;

The ink is poured into one end of the metal mask, and a certain pressure is applied to the ink portion of the metal mask by the scraper while moving toward the other end of the metal mask, and the ink is squeezed from the hollow micro-pattern structure by the scraper during the movement. Forming a micropattern of the array on the transparent substrate layer;

The above steps are repeated to form a plurality of sets of arrays of micropatterns having different colors on the transparent substrate layer.

As a further improvement of the present invention, the preparation method of the metal mask is specifically:

Applying a photoresist or a photolithographic dry film uniformly on a metal substrate;

By laser direct writing or photomask exposure, after development, an embossed micro-pattern structure is formed;

Forming a metal deposition layer on the surface of the conductive portion of the metal substrate by a metal electroforming process;

The photoresist is removed and the metal deposition layer is separated from the metal substrate to form a metal mask having a hollow micro-pattern structure.

As a further improvement of the present invention, the metal mask has a thickness of 5 um to 100 um.

As a further improvement of the present invention, the material of the metal mask is Ni, Cu, Ni-Co alloy, or Fe-Ni alloy.

As a further improvement of the present invention, the metal mask is provided with a registration mark, and the transparent substrate layer and the metal mask are aligned by CCD or mechanical sleeve.

The invention has the following beneficial effects:

The moiré image formed by the moiré image film has color, dynamic, and stereoscopic characteristics, while retaining horizontal parallax and vertical parallax, and can display clear color three-dimensional moving images, which not only provides recognition effect, but also further increases The difficulty in manufacturing the anti-counterfeiting product allows the observer to observe the color three-dimensional dynamic graphic without any special observation skills in any light environment.

The Moir image film is easy to prepare, the micro-pattern printing cost is low and the resolution is high; the metal mask is easy to manufacture.

DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the description of the prior art will be briefly described below. Obviously, the drawings in the following description are only It is a few embodiments described in the present invention, and other drawings can be obtained from those skilled in the art without any inventive effort.

1 is a schematic structural view of a moiré image film according to an embodiment of the present invention;

2a and 2b are schematic structural views of a micro-pattern array layer and a microlens array according to an embodiment of the present invention;

3a-3f are process flow diagrams of a method for preparing a moiré image film according to an embodiment of the present invention;

4a and 4b are schematic structural views of a first metal mask and a second metal mask, respectively, according to an embodiment of the present invention;

5a-5d are process flow diagrams of a method for preparing a metal mask according to an embodiment of the present invention.

detailed description

The invention will be described in detail below in conjunction with the specific embodiments shown in the drawings. However, the embodiments are not intended to limit the invention, and the structural, method, or functional changes made by those skilled in the art in accordance with the embodiments are included in the scope of the present invention.

The invention discloses a micro-printing color dynamic stereoscopic moiré image film, comprising a transparent substrate layer, a microlens array layer on one side of the transparent substrate layer, and a micro-pattern array on the other side of the transparent substrate layer. The layer, the microlens array layer comprises a plurality of array-arranged microlenses, the micro-pattern array layer comprising a plurality of sets of micro-patterns arranged in an array and having different colors, the array arrangement of the micro-lenses being matched with the array arrangement of the micro-patterns.

As shown in FIG. 1, in a specific embodiment of the present invention, a moiré image film includes a transparent substrate layer 1, a microlens array layer 2, and a micro-pattern array layer 3, wherein the microlens array layer includes a plurality of array arrangements. The microlens 21, the micro-pattern array layer comprises a plurality of arrays of first micro-patterns 31 and second micro-patterns 32, the first micro-patterns 31 and the second micro-patterns 32 having different colors.

In the present embodiment, the moiré image formed by the moiré image film not only has a stereoscopic and dynamic effect, but also can be colored, and the moiré image film will be described in detail below.

The moiré image film combined with the microlens micro-pattern retains both horizontal parallax and vertical parallax, ensuring a large viewing angle, allowing the observer to observe three-dimensional color patterns without any special observation techniques in any light environment. To display clear 3D images, microlenses and micropatterns must be closely matched and dense In other embodiments, the color of the micropattern is not limited to two sets.

The structure of the micropattern in this embodiment matches the structure of the microlens. There are two ways of arranging the microlens array layers, that is, a square arrangement or a hexagonal arrangement. The array arrangement of micropatterns corresponds to the corresponding microlens array arrangement.

The magnification of the moiré image film in this embodiment is:

The micropattern in the micropattern array layer has an overall size of 10 μm to 100 μm and a line width of 1 μm to 20 μm. According to the above formula, the micro-pattern array is enlarged by the microlens array, and the pattern magnification M is 20 ∞. When r=1, the formula for calculating the magnification of the graph is

When θ = 0.1°, the pattern magnification M is 573 times according to the above formula. Preferably, the micro-pattern height is 5 μm to 100 μm, and if the micro-pattern is 20 μm high, the Moir-amplified pattern size is 11.45 mm, which can be recognized by the naked eye.

When there is a certain distance between the microlens array and the micro-pattern array, the movement of the micro-pattern array is caused by the change in the viewing angle. Assuming that the period of the microlens array is a, the period of the micropattern array is b, the distance between the microlens array and the micropattern is h (the thickness of the transparent substrate layer), and the period of the magnified image is L, which deviates from the vertical direction. In order to observe the angle, the period of movement of the moiré image formed by the moiré image film is:

The dynamic effect of the moiré image, the larger the image period, the larger the spacing h of the microlens and the micropattern, the smaller the period of the micropattern array, the better the dynamic effect. Mohr images have two dynamic effects:

1) If the arrangement direction of the micro-pattern array and the microlens array is the same, the arrangement period is different, and the observer changes the viewing angle, the direction of motion of the Moir magnified image is the same or opposite to the direction in which the observer moves.

2) If the micro-pattern array and the microlens cycle are the same, but have a small angle θ between them, the moiré image moves laterally when the eye moves longitudinally, and the moiré image moves longitudinally when the eye moves laterally.

The steric effect is due to the formation of binocular parallax at the time of observation. When the micro-pattern period is smaller than the micro-lens period, the effect of pattern sinking is generated. When the micro-pattern period is larger than the micro-lens period, the effect of the pattern floating is generated, and the moire-magnified images of the floating and sinking form a three-dimensional effect.

2a and 2b are respectively schematic structural views of a micro-pattern array layer and a microlens array according to an embodiment of the present invention. The first micro-pattern 31 in the micro-pattern array layer is a solar micro-pattern having a first color and arranged in an array, and the second micro-pattern 32 is a crescent micro-pattern having a second color and arranged in an array, and the micro-lens array layer 2 includes a plurality of Microlenses 21 having a corresponding array arrangement.

The sun micropattern having the first color and the crescent micropattern having the second color have an overall size of 10 μm to 100 μm and a line width of 1 μm to 20 μm. According to the above formula, the micro-pattern array is magnified by the microlens array and can be observed with the naked eye.

The preparation method of the moiré image film in the invention specifically includes:

S1, providing a transparent substrate layer;

S2, preparing a microlens array layer on a side of the transparent substrate layer, the microlens array layer comprising a plurality of microlenses arranged in an array;

Step S3 is specifically as follows:

The preparation method of the moiré image film in the specific embodiment of the present invention will be described in detail below with reference to Figs. 3a to 3f.

First, a transparent substrate layer 1 is provided, and array-arranged microlenses 21 are prepared on the transparent substrate layer side to form a microlens array layer.

The basic principle of the micro-pattern part of the metal mask is used to transmit ink, and the non-micro-pattern part is not ink-permeable.

As shown in FIG. 3a, the first metal mask 41 is placed on the transparent substrate layer 1 and aligned. The first metal mask 41 includes a plurality of first hollow micro-pattern structures arranged in an array;

As shown in FIGS. 3a and 3b, a first ink 51 having a first color is poured into one end of the first metal mask 41, and a certain pressure is applied to the first ink portion of the first metal mask by the squeegee 6. At the same time, moving toward the other end of the first metal mask 41, the first ink 51 is pressed by the squeegee 6 from the first hollow micro-pattern structure onto the transparent substrate layer 1 during the movement. Due to the viscous action of the ink, the print is fixed within a certain range, and the squeegee 6 is always in line contact with the first metal mask 41 and the transparent substrate layer 1 during printing.

When the squeegee 6 is scraped over the entire layout and lifted up, and the first metal mask is lifted up, and the first ink 51 is lightly scraped back to the initial position, the first micro-array of the array arrangement shown in FIG. 3c can be formed. Figure 31.

Similarly, as shown in FIGS. 3d to 3f, the second micro-pattern 32 of the array arrangement can also be formed by the second metal mask 42 and the second ink 52 having the second color and the squeegee 6, the printing principle and The printing principle of the first micro-pattern is the same and will not be described here. Different from the first micro-pattern, the first metal mask 41 is placed in close contact with the transparent substrate layer 1, and the second metal mask 42 is placed in close contact with the first micro-pattern, away from the transparent substrate layer. 1 has a certain distance.

4a and 4b are schematic views showing the structure of a first metal mask 41 having a solar micropattern and a second metal mask 42 having a crescent micropattern in an embodiment of the present invention. In other embodiments, the micro-patterns can also be other graphics or text or a combination thereof.

In Figures 4a, 4b, the black portion is the occlusion layer and the micro-pattern is the hollow portion. The overall size of the hollow portion is 5 um to 100 um, and the line width is 0.5 μm to 20 μm. The thickness of the metal mask is 5 μm to 100 μm, and the metal mask has a cross-alignment mark for precise alignment in post-production.

When the micro-pattern is printed, the cross-alignment mark on the first metal mask and the second metal mask is aligned by CCD or mechanical sleeve, thereby realizing a color micro-pattern array with higher contrast.

The metal mask in the present invention adopts a metal deposition growth method, and the specific steps are as follows:

As shown in FIG. 5a, a photoresist or a photolithographic dry film 402 is uniformly coated on the metal substrate 401, and the photoresist may be negative or positive, and has a thickness of 5 um to 100 um;

By laser direct writing or photomask exposure, after development, the embossed micro-pattern structure shown in FIG. 5b is formed;

Referring to Figure 5c, through the metal electroforming process, a metal deposition layer 403 is formed on the surface of the metal substrate 401 exposed bottom conductive portion;

The photoresist or the photolithographic dry film is removed, and the metal deposition layer 403 is separated from the metal substrate 401 to form a metal mask having a hollow micro-pattern structure as shown in FIG. 5d.

The laser direct writing lithography system has a graphic resolution of 0.2 um to 0.5 um. Therefore, the present invention can realize micro-pattern exposure of a line width of 1 um or more. Therefore, the above-mentioned metal mask has a micro-pattern line width of up to 1 micrometer and an overall size of 10 micrometers. Preferably, in the present embodiment, the thickness of the metal mask is 5 um to 100 um, and the material is Ni, Cu, Ni-Co alloy, or Fe-Ni alloy.

The invention can be applied to anti-counterfeiting technology, and the new anti-counterfeiting technology visually requires: color, dynamic, multi-dimensional, multi-channel and layering effects.

If you use traditional printing methods to produce color micro-patterns, take the example of Luscher's large-format screen and offset printing system JetScreen2000, which has 256 nozzles for inkjet printing. Head, can provide output of 700dpi resolution image; Amanda, a subsidiary of Autoprint Srl., introduces the new thermal inkjet printer DigitAll, which can achieve 720×720dpi resolution image output; in digital screen printing, Scitex's new type The ultra-wide format Grandjet press has a resolution of 370 x 370 dpi; Nur's Fresco press can achieve a resolution of 720 dpi. Therefore, at the current level of printing or printing, high-precision (position error less than 1%) and high-resolution (10 μm) micro-patterning cannot be achieved, so that the accuracy of moiré amplification is not achieved, and the printing method is inefficient. It is also difficult to achieve mass production and low-cost production of micro graphics.

Compared with the prior art, the present invention has the following beneficial effects:

The Moir image film is easy to prepare, the micro-pattern printing cost is low and the resolution is high (the overall size of the micro-pattern is 5um~100um, the line width is 0.5μm~20μm); the metal mask is easy to manufacture.

It is apparent to those skilled in the art that the present invention is not limited to the details of the above-described exemplary embodiments, and the present invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the present embodiments are to be considered as illustrative and not restrictive, and the scope of the invention is defined by the appended claims instead All changes in the meaning and scope of equivalent elements are included in the present invention. Any reference signs in the claims should not be construed as limiting the claim.

Moreover, it should be understood that although this description is described in terms of embodiments, not every implementation The method includes only one independent technical solution, and the description of the specification is merely for the sake of clarity, and the technical solutions in the embodiments may be combined as appropriate, and the technical solutions in the respective embodiments may be combined as appropriate to form a person skilled in the art. Other embodiments that can be understood.

Claims

A micro-printing color dynamic stereoscopic moiré image film, characterized in that the moiré image film comprises a transparent substrate layer, a microlens array layer on one side of the transparent substrate layer, and a transparent substrate layer a micro-pattern array layer on one side, the microlens array layer comprising a plurality of array-arranged microlenses, the micro-pattern array layer comprising a plurality of sets of micro-patterns arranged in an array and having different colors, the array of microlenses The cloth matches the array arrangement of the micro graphics.
The moiré image film according to claim 1, wherein the microlens array layer and the micropattern array layer are in a square array arrangement or a hexagon array arrangement.
The moiré image film according to claim 1, wherein the micropattern in the micropattern array layer has an overall size of 10 μm to 100 μm and a line width of 1 μm to 20 μm.
The moiré image film according to claim 1, wherein the magnification of the moiré image film is:

The period ratio of the microlens array to the micro-pattern array is r, and the angle between them is θ.
The moiré image film according to claim 4, wherein when the period ratio r of the microlens array and the micropattern array is 1, the magnification of the moiré image film is:
The moiré image film according to claim 1, wherein said moiré image is thin The period of movement of the moiré image formed by the film is:

The period of the microlens array is a, the period of the micropattern array is b, the distance between the microlens array and the micropattern is h, and the angle of observation from the vertical direction is Ф.
A method of fabricating a microprint-based color dynamic stereoscopic moiré image film according to claim 1, wherein the method comprises:

S1, providing a transparent substrate layer;

S2, preparing a microlens array layer on a side of the transparent substrate layer, the microlens array layer comprising a plurality of microlenses arranged in an array;

S3, preparing a micro-pattern array layer on the other side of the transparent substrate layer, the micro-pattern array layer comprising a plurality of sets of micro-patterns arranged in an array and having different colors, the array arrangement of the micro-lenses and the array of micro-patterns The cloth matches.
The preparation method according to claim 7, wherein the step S3 is specifically:

The metal mask is placed on the transparent substrate layer and aligned, and the metal mask comprises a plurality of arrayed hollow micro-pattern structures;

The ink is poured into one end of the metal mask, and a certain pressure is applied to the ink portion of the metal mask by the scraper while moving toward the other end of the metal mask, and the ink is squeezed from the hollow micro-pattern structure by the scraper during the movement. Forming a micropattern of the array on the transparent substrate layer;

Repeat the above steps to form several sets of arrays on the transparent substrate layer and have different colors Graphics.
The preparation method according to claim 8, wherein the preparation method of the metal mask is specifically:

Applying a photoresist or a photolithographic dry film uniformly on a metal substrate;

By laser direct writing or photomask exposure, after development, an embossed micro-pattern structure is formed;

Forming a metal deposition layer on the surface of the conductive portion of the metal substrate by a metal electroforming process;

The photoresist is removed and the metal deposition layer is separated from the metal substrate to form a metal mask having a hollow micro-pattern structure.
The preparation method according to claim 9, wherein the metal mask has a thickness of 5 um to 100 um.
The preparation method according to claim 9, wherein the material of the metal mask is Ni, Cu, a Ni-Co alloy, or an Fe-Ni alloy.
The preparation method according to claim 8, wherein the metal mask is provided with a registration mark, and the transparent substrate layer and the metal mask are aligned by a CCD or a mechanical sleeve.