阅读说明：本技术 光学防伪元件及其制备方法和光学防伪产品 (Optical anti-counterfeiting element, preparation method thereof and optical anti-counterfeiting product ) 是由 *** 朱军 张巍巍 张宝利 李妍 于 2018-07-13 设计创作，主要内容包括：本发明实施例提供一种光学防伪元件及其制备方法和光学防伪产品,属于光学防伪领域。该光学防伪元件包括：透明的起伏结构层,包括第一起伏结构和第二起伏结构,所述第一起伏结构和所述第二起伏结构满足以下条件：所述第一起伏结构的深宽比小于所述第二起伏结构的深宽比,和/或所述第一起伏结构的比体积小于所述第二起伏结构的比体积；以及干涉光变镀层,形成在所述第一起伏结构上,其中,所述干涉光变镀层在被从两侧观察时均呈现光学变色效果,所述光学防伪元件被透射观察时呈现所述第二起伏结构的边界形成的图像。藉此,实现了光学防伪元件在被从两侧进行观察时均能同时呈现图像效果和光学变色效果,并且透射观察时具有镂空效果。(The embodiment of the invention provides an optical anti-counterfeiting element, a preparation method thereof and an optical anti-counterfeiting product, belonging to the field of optical anti-counterfeiting. The optical security element comprises: a transparent relief structure layer comprising a first relief structure and a second relief structure, the first relief structure and the second relief structure satisfying the following condition: the aspect ratio of the first relief structure is smaller than that of the second relief structure, and/or the specific volume of the first relief structure is smaller than that of the second relief structure; and the interference light variable plating layer is formed on the first relief structure, wherein the interference light variable plating layer shows an optical color change effect when being observed from two sides, and the optical anti-counterfeiting element shows an image formed by the boundary of the second relief structure when being observed in a transmission mode. Therefore, the optical anti-counterfeiting element can simultaneously show the image effect and the optical color changing effect when being observed from two sides, and has a hollow effect when being observed in a transmission mode.)

1. An optical security element, comprising:

a transparent relief structure layer comprising a first relief structure and a second relief structure, the first relief structure and the second relief structure satisfying the following condition: the aspect ratio of the first relief structure is smaller than that of the second relief structure, and/or the specific volume of the first relief structure is smaller than that of the second relief structure; and

and the interference light variable plating layer is formed on the first relief structure, wherein the interference light variable plating layer shows an optical color changing effect when being observed from two sides, and the optical anti-counterfeiting element shows an image formed by the boundary of the second relief structure when being observed in a transmission mode.

2. An optical security element according to claim 1, further comprising: a transparent substrate, the relief structure layer being formed on at least a partial region of the substrate.

3. An optical security element as claimed in claim 1 wherein the interference light variable coating comprises a first partially transparent layer, a first dielectric layer, a reflective layer, a second dielectric layer and a second partially transparent layer laminated in that order.

4. An optical security element according to claim 3, wherein the first partially transparent layer is different from the second partially transparent layer and/or the first dielectric layer is different from the second dielectric layer.

5. An optical security element as claimed in claim 1 wherein the interference light variable coating comprises a first partially transparent layer, a dielectric layer and a second partially transparent layer laminated in that order.

6. An optical security element according to claim 5, wherein the first partially transparent layer is different from the second partially transparent layer.

7. An optical security product comprising an optical security element according to any one of claims 1 to 6.

8. A preparation method of an optical anti-counterfeiting element is characterized by comprising the following steps:

forming a transparent relief structure layer on at least a partial area of a substrate, wherein the relief structure layer comprises a first relief structure and a second relief structure, and the first relief structure and the second relief structure satisfy the following conditions: the aspect ratio of the first relief structure is smaller than that of the second relief structure, and/or the specific volume of the first relief structure is smaller than that of the second relief structure; and

and forming an interference light variable coating on the first relief structure, wherein the interference light variable coating shows an optical color change effect when being observed from two sides, and the optical anti-counterfeiting element shows an image formed by the boundary of the second relief structure when being observed in a transmission mode.

9. The method of claim 8, wherein the forming of the interference light variation coating on the first relief structure under the condition that the aspect ratio of the first relief structure is smaller than the aspect ratio of the second relief structure, the specific volume of the first relief structure is smaller than the specific volume of the second relief structure, and the outermost layer of the interference light variation coating away from the first relief structure is not reacted with a corrosive atmosphere comprises:

forming the interference light variable plating layer on the relief structure layer, wherein the interference light variable plating layer at least covers the first relief structure; and placing the substrate, the relief structure layer and the structure formed by the interference light variation plating layer in the corrosion atmosphere until the interference light variation plating layer covered on the second area is completely or partially corroded; or

Forming the interference light variable plating layer on the relief structure layer, wherein the interference light variable plating layer at least covers the first relief structure; coating a coating layer on the interference light variation coating layer, wherein the coating layer at least covers the part of the interference light variation coating layer corresponding to the first photovoltaic structure, and the coating layer prevents the interference light variation coating layer covering the first photovoltaic structure from being corroded by the corrosion atmosphere; and placing the structure formed by the substrate, the relief structure layer and the interference light variable plating layer in the corrosion atmosphere until the interference light variable plating layer covered on the second area is completely or partially corroded.

10. The method of claim 8, wherein the forming of the interference light variation coating on the first relief structure under the condition that the aspect ratio of the first relief structure is smaller than that of the second relief structure, the specific volume of the first relief structure is larger than that of the second relief structure, and the outermost layer of the interference light variation coating away from the first relief structure is not reacted with a corrosive atmosphere comprises:

forming the interference light variable plating layer on the relief structure layer, wherein the interference light variable plating layer at least covers the first relief structure; and

and placing the structure formed by the substrate, the relief structure layer and the interference light variable plating layer in the corrosion atmosphere until the interference light variable plating layer covered on the second area is completely or partially corroded.

11. The method according to claim 8, wherein in a case where an aspect ratio of the first relief structure is larger than an aspect ratio of the second relief structure, and/or an outermost layer of the interference light variation plating layer away from the first relief structure reacts with a corrosive atmosphere, a specific volume of the first relief structure is smaller than a specific volume of the second relief structure, and the forming of the interference light variation plating layer on the first relief structure comprises:

forming the interference light variable plating layer on the relief structure layer, wherein the interference light variable plating layer at least covers the first relief structure;

coating a coating layer on the interference light variation coating layer, wherein the coating layer at least covers the part of the interference light variation coating layer corresponding to the first photovoltaic structure, and the coating layer prevents the interference light variation coating layer covering the first photovoltaic structure from being corroded by the corrosion atmosphere; and

and placing the structure formed by the substrate, the relief structure layer and the interference light variable plating layer in the corrosion atmosphere until the interference light variable plating layer covered on the second area is completely or partially corroded.

12. The method of claim 8, wherein the interference light variation plating layer comprises a first partially transparent layer, a first dielectric layer, a reflective layer, a second dielectric layer, and a second partially transparent layer, which are sequentially stacked.

13. Method for producing according to claim 12, characterized in that the first partially transparent layer is different from the second partially transparent layer and/or the first dielectric layer is different from the second dielectric layer.

14. The method of claim 8, wherein the interference light variation plating layer comprises a first partially transparent layer, a dielectric layer, and a second partially transparent layer, which are sequentially stacked.

15. A producing method according to claim 14, wherein said first partially transparent layer is different from said second partially transparent layer.

Technical Field

The invention relates to the field of optical anti-counterfeiting, in particular to an optical anti-counterfeiting element, a preparation method thereof and an optical anti-counterfeiting product.

Background

In order to prevent counterfeiting by means of scanning, copying and the like, optical anti-counterfeiting technology is widely adopted in various high-security or high-value-added printed matters such as bank notes, credit cards, passports, securities and the like, and a very good effect is achieved. Such as security threads, security strips in banknotes, etc.

In recent years, optical anti-counterfeiting products with window structures are widely applied. The products generally have different visual effects when being observed from the front side and the back side and even being observed in a transmission mode, and the anti-counterfeiting strength is greatly enhanced. For example, the new edition 20 Euro adopts an anti-counterfeiting wide strip with a window structure, different holographic digital images can be observed on the front side and the back side, a hollowed-out Europa character head portrait can be observed in a transmission mode, and the anti-counterfeiting effect is excellent due to the fact that strong visual impact is achieved. For another example, the new plate 5 pound plastic money has an anti-counterfeiting wide strip, the forward and reverse observation of the tower in the window part has different colors, and the perspective observation of the background of the tower has a hollow transparent effect.

On the other hand, the multilayer plating interference light variation technology is receiving more and more attention because it shows strong optical color variation effect under different viewing angles. The multi-layer coating interference light variation technology generally adopts a vapor deposition method to realize evaporation of a reflecting layer, a dielectric layer and a partially transparent layer (or an absorption layer). The three-layer structure composed of the reflecting layer, the dielectric layer and the partially transparent layer is a basic unit of a common interference light variable coating. The different angles present different color characteristics, viewed from the partially transparent layer side. For example, the fifth set 2015 of 100 yuan RMB security threads is made by multilayer interference light variation technology, which is magenta when viewed at a vertical angle and green when viewed at an oblique angle. If the microstructure optical anti-counterfeiting technology and the multilayer interference optical variable technology are combined, the dual advantages of the optical image (such as a holographic image) presented by the microstructure and the optical variable effect presented by the multilayer coating can be effectively exerted, and the anti-counterfeiting effect can be further enhanced. The safety line in the aerospace commemorative money issued in 2015 adopts an optical anti-counterfeiting technology combining an optical microstructure and multilayer interference light variation.

It can be expected that if the observation of both sides of the product has image effect and light variation effect, and the transmission observation has local hollow effect, and the hollow area is aligned with the image, the anti-counterfeiting effect can be greatly improved, and the anti-counterfeiting product has good application prospect in the occasion with window characteristics (such as the window on the bank note), but the anti-counterfeiting product does not see the product at present.

Disclosure of Invention

The invention aims to provide an optical anti-counterfeiting element, a preparation method thereof and an optical anti-counterfeiting product, which can realize that the optical anti-counterfeiting element can simultaneously show an image effect and an optical color changing effect when being observed from two sides, and has a local hollow effect through transmission observation, and the hollow area is accurately aligned with an image.

In order to achieve the above object, one aspect of the present invention provides an optical security element comprising: a transparent relief structure layer comprising a first relief structure and a second relief structure, the first relief structure and the second relief structure satisfying the following condition: the aspect ratio of the first relief structure is smaller than that of the second relief structure, and/or the specific volume of the first relief structure is smaller than that of the second relief structure; and the interference light variable plating layer is formed on the first relief structure, wherein the interference light variable plating layer shows an optical color change effect when being observed from two sides, and the optical anti-counterfeiting element shows an image formed by the boundary of the second relief structure when being observed in a transmission mode.

Optionally, the optical security element further comprises: a transparent substrate, the relief structure layer being formed on at least a partial region of the substrate.

Optionally, the interference light variation plating layer includes a first partially transparent layer, a first dielectric layer, a reflective layer, a second dielectric layer, and a second partially transparent layer, which are sequentially stacked.

Optionally, the first partially transparent layer is different from the second partially transparent layer, and/or the first dielectric layer is different from the second dielectric layer.

Optionally, the interference light variation plating layer comprises a first partially transparent layer, a dielectric layer and a second partially transparent layer which are sequentially stacked.

Optionally, the first partially transparent is different from the second partially transparent layer.

In addition, another aspect of the invention provides an optical anti-counterfeiting product, which comprises the optical anti-counterfeiting element.

In addition, another aspect of the present invention provides a method for preparing an optical security element, the method comprising: forming a transparent relief structure layer on at least a partial area of a substrate, wherein the relief structure layer comprises a first relief structure and a second relief structure, and the first relief structure and the second relief structure satisfy the following conditions: the aspect ratio of the first relief structure is smaller than that of the second relief structure, and/or the specific volume of the first relief structure is smaller than that of the second relief structure; and forming an interference light variable coating on the first relief structure, wherein the interference light variable coating shows an optical color change effect when observed from two sides, and the optical anti-counterfeiting element shows an image formed by the boundary of the second relief structure when observed in a transmission mode.

Optionally, in a case that an aspect ratio of the first relief structure is smaller than an aspect ratio of the second relief structure, a specific volume of the first relief structure is smaller than a specific volume of the second relief structure, and an outermost layer of the interference light variation plating layer away from the first relief structure does not react with a corrosive atmosphere, the forming of the interference light variation plating layer on the first relief structure includes: forming the interference light variable plating layer on the relief structure layer, wherein the interference light variable plating layer at least covers the first relief structure; and placing the substrate, the relief structure layer and the structure formed by the interference light variation plating layer in the corrosion atmosphere until the interference light variation plating layer covered on the second area is completely or partially corroded; or forming the interference light variable plating layer on the relief structure layer, wherein the interference light variable plating layer at least covers the first relief structure; coating a coating layer on the interference light variation coating layer, wherein the coating layer at least covers the part of the interference light variation coating layer corresponding to the first photovoltaic structure, and the coating layer prevents the interference light variation coating layer covering the first photovoltaic structure from being corroded by the corrosion atmosphere; and placing the structure formed by the substrate, the relief structure layer and the interference light variable plating layer in the corrosion atmosphere until the interference light variable plating layer covered on the second area is completely or partially corroded.

Optionally, in a case that an aspect ratio of the first relief structure is smaller than an aspect ratio of the second relief structure, a specific volume of the first relief structure is larger than a specific volume of the second relief structure, and an outermost layer of the interference light variation plating layer away from the first relief structure does not react with a corrosive atmosphere, the forming of the interference light variation plating layer on the first relief structure includes: forming the interference light variable plating layer on the relief structure layer, wherein the interference light variable plating layer at least covers the first relief structure; and placing the structure formed by the substrate, the relief structure layer and the interference light variable plating layer in the corrosion atmosphere until the interference light variable plating layer covered on the second area is completely or partially corroded.

Optionally, in a case where an aspect ratio of the first relief structure is larger than that of the second relief structure, and/or an outermost layer of the interference light variation plating layer away from the first relief structure reacts with a corrosive atmosphere, a specific volume of the first relief structure is smaller than that of the second relief structure, the forming of the interference light variation plating layer on the first relief structure includes: forming the interference light variable plating layer on the relief structure layer, wherein the interference light variable plating layer at least covers the first relief structure; coating a coating layer on the interference light variation coating layer, wherein the coating layer at least covers the part of the interference light variation coating layer corresponding to the first photovoltaic structure, and the coating layer prevents the interference light variation coating layer covering the first photovoltaic structure from being corroded by the corrosion atmosphere; and placing the structure formed by the substrate, the relief structure layer and the interference light variable plating layer in the corrosion atmosphere until the interference light variable plating layer covered on the second area is completely or partially corroded.

Optionally, the interference light variation plating layer includes a first partially transparent layer, a first dielectric layer, a reflective layer, a second dielectric layer, and a second partially transparent layer, which are sequentially stacked.

Optionally, the first partially transparent layer is different from the second partially transparent layer, and/or the first dielectric layer is different from the second dielectric layer.

Optionally, the interference light variation plating layer comprises a first partially transparent layer, a dielectric layer and a second partially transparent layer which are sequentially stacked.

Optionally, the first partially transparent layer is different from the second partially transparent layer.

Through above-mentioned technical scheme, transparent undulation structural layer makes optical anti-fake element present image effect when being observed from both sides, interferes light change cladding material and makes optical anti-fake element present the optical discoloration effect when being observed from both sides, so, has realized making optical anti-fake element homoenergetic present image effect and optical discoloration effect simultaneously when being observed from both sides. And part or all of the interference light variable coating of the second relief structure area is removed, so that the anti-counterfeiting element presents an image formed by the boundary of the second relief structure when being observed in a transmission mode, namely the hollow area is completely aligned with the image presented by the first relief structure.

Additional features and advantages of the invention will be set forth in the detailed description which follows.

Drawings

The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the embodiments of the invention without limiting the embodiments of the invention. In the drawings:

fig. 1 is a schematic structural diagram of an optical security element according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a top view of an exemplary optical security element provided in accordance with another embodiment of the present invention;

FIG. 3a is a schematic representation of a cross-sectional view of the optical security element of FIG. 2 taken along the line X-X in FIG. 2 according to another embodiment of the present invention;

FIG. 3b is a schematic representation of another cross-sectional view of the optical security element of FIG. 2 taken along line X-X of FIG. 2 according to another embodiment of the present invention;

FIG. 4 is a flow chart of a method for producing an optical security element according to another embodiment of the present invention;

fig. 5 to 7 are schematic diagrams of cross-sectional views of an optical security element in the manufacture of an optical security element corresponding to the cross-sectional view shown in fig. 3a according to another embodiment of the present invention; and

figures 8 to 9 are schematic diagrams of cross-sectional views of an optical security element in the manufacture of an optical security element corresponding to the cross-sectional view shown in figure 3a according to a further embodiment of the present invention;

description of the reference numerals

1 substrate 2 relief structure layer

3 first partially transparent layer of interference light variation coating 31

32 first dielectric layer 33 reflective layer

34 second dielectric layer 35 second partially transparent layer

36 dielectric layer 4 functional coating

5 coating layer

Detailed Description

The following detailed description of embodiments of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating embodiments of the invention, are given by way of illustration and explanation only, not limitation.

One aspect of embodiments of the present invention provides an optical security element. Fig. 1 is a schematic structural diagram of an optical security element according to an embodiment of the present invention. As shown in fig. 1, the optical anti-counterfeiting element comprises a base relief structure layer 2 and an interference light variable plating layer 3. Wherein the relief structure layer 2 is transparent. The relief structure layer 2 includes a relief structure. The interference light variable plating layer 3 is formed on at least a partial region of the relief structure layer 2, and the interference light variable plating layer 3 exhibits an optical discoloration effect when viewed from both sides.

The relief structure layer enables the optical anti-counterfeiting element to show an image effect when being observed from two sides, and the interference light variable plating layer enables the optical anti-counterfeiting element to show an optical color-changing effect when being observed from two sides, so that the optical anti-counterfeiting element can simultaneously show the image effect and the optical color-changing effect when being observed from two sides, and the anti-counterfeiting performance of the optical anti-counterfeiting element is improved. The relief structure layer comprises a first relief structure and a second relief structure, and the interference light variable plating layer covers the first relief structure, so that the optical anti-counterfeiting element has a partially hollow transparent effect when being observed in a transmission mode, an image formed by the boundary of the second relief structure can be presented, and the hollow area and the image area are accurately aligned. Therefore, the anti-counterfeiting dimension of the optical anti-counterfeiting element is increased, and the anti-counterfeiting performance of the optical anti-counterfeiting element is further improved.

In addition, the relief structure in the relief structure layer enables the optical anti-counterfeiting element to present an image effect when being observed, and the image effect presented by the optical anti-counterfeiting element when being observed can be changed by changing the relief structure. In an embodiment of the present invention, the cross-section of the first relief structure and/or the second relief structure may be a cosine structure, a sawtooth structure, a cylindrical structure, a spherical structure, a pyramid structure, a square wave structure, or a combination thereof.

The first relief structure and the second relief structure must satisfy the following condition: first junctionThe aspect ratio of the structures is smaller than the aspect ratio of the second relief structures and/or the specific volume of the first relief structures is smaller than the specific volume of the second relief structures. First undulate structure and second undulate structure satisfy above-mentioned condition and can be so that when preparation optics anti-fake element, realize accurate fretwork, interfere the accurate only cover of light change cladding material on first undulate structure promptly, and the accurate location of image that fretwork region and first undulate structure present. The aspect ratio of the relief structure refers to the ratio of the depth of the relief structure to the width in the direction of the period. The specific volume of the relief structure refers to the ratio of the volume of liquid that just completely covers the surface of the relief structure to the projected area of the relief structure on the horizontal plane, when the relief structure layer is placed in a horizontal state. By this definition, the aspect ratio is a dimensionless physical quantity, the dimension of the specific volume being um³/um². By this definition, a planar structure is considered to be a relief structure having an aspect ratio of zero and a specific volume of zero. The aspect ratio and the specific volume are two physical quantities which are not directly related in quantity. For example, if the a structure is a one-dimensional sawtooth grating with a depth of 1um and a period of 1um, the aspect ratio is 1 and the specific volume is 0.5um³/um²(ii) a The structure B is a one-dimensional sawtooth grating with the depth of 2um and the period of 4um, the depth-to-width ratio is 0.5, and the specific volume is 1um³/um². That is, the aspect ratio of the a-structures is greater than the aspect ratio of the B-structures, and the specific volume of the B-structures is greater than the B-volume of the a-structures. In addition, different hollowing processes can be adopted according to the difference of the depth-to-width ratio and the specific volume of the first undulation structure and the second undulation structure.

Optionally, in an embodiment of the present invention, the optical security element may further include an at least partially transparent substrate, and the relief structure layer is formed on at least a partial region of the substrate.

Alternatively, in embodiments of the present invention, the first relief structure and the second relief structure may be wholly or partially periodic structures. Wherein, the period can be more than 1um and less than 20 um. Wherein the periodicity of the first relief structure is for molding an optical effect exhibited by the first relief structure, and the periodicity of the second relief structure is for forming the hollow feature.

Optionally, in an embodiment of the present invention, an aspect ratio of the first relief structure is less than 0.3, and an aspect ratio of the second relief structure is greater than 0.3. Preferably, the aspect ratio of the first relief structure is less than 0.2 and the aspect ratio of the second relief structure is greater than 0.5.

Optionally, in embodiments of the present invention, the first photovoltaic structure has a specific volume of less than 1um³/um²The specific volume of the second undulation structure is more than 1um³/um². Preferably, the first photovoltaic structure has a specific volume of less than 0.5um³/um²The specific volume of the second relief structure is more than 1.5um³/um²。

Alternatively, in an embodiment of the present invention, the interference light variation plating layer may include a first partially transparent layer, a first dielectric layer, a reflective layer, a second dielectric layer, and a second partially transparent layer, which are sequentially stacked. In the five-layer structure, two sides of the reflecting layer are respectively provided with a dielectric layer and a partially transparent layer optically variable coating unit, so that when the interference optically variable coating is observed from two sides, the two sides both have optical color changing effect. In addition, the first partially transparent layer and the second partially transparent layer may be the same or different; the first dielectric layer and the second dielectric layer may be the same or different. When the first partially transparent layer is different from the second partially transparent layer and/or the first dielectric layer is different from the second dielectric layer, the optically variable color effects exhibited by the two sides are different when the optical security element is viewed from both sides, e.g., one side exhibits a transition of a color and B color and the other side exhibits a transition of C color and D color.

Optionally, the interference light variation plating layer may further include a first partially transparent layer, a dielectric layer, and a second partially transparent layer sequentially stacked. In the three-layer structure, the second partially transparent layer provides a reflective layer of one side interference light variation plating layer, and the first partially transparent layer provides a reflective layer of the other side interference light variation plating layer, so that both sides exhibit optical discoloration effects when viewed from both sides. In addition, the first partially transparent layer and the second partially transparent layer may be the same or different. When the first partially transparent layer is different from the second partially transparent layer, the optical color-changing effect of the two sides is different when the optical security element is observed from the two sides.

Alternatively, in embodiments of the invention, the partially transparent layer (the innermost plating layer) adjacent to the relief structure layer is selected to be aluminium or an aluminium alloy in order to obtain a hollowing effect. This is because aluminum is easily removed by reacting with various corrosive environments, such as alkali or acid. If part of the transparent layer adjacent to the relief structure layer is removed by reaction, the other plating layers thereon can be lifted off even if they cannot react with corrosive environment.

Optionally, in embodiments of the present invention, the optical security element may further comprise a protective layer and/or a functional coating formed on the side of the optical security element opposite the substrate. The protective layer and/or functional coating may be a single layer or a plurality of layers. The protective layer and/or functional coating generally has a protective effect to protect the interference light variable coating from corrosion by external conditions in the use environment, and also generally has an effect of bonding with other substrates, such as paper. Further, in the case where the optical security element includes both the protective layer and the functional coating layer, the functional coating layer is formed on the protective layer.

In order to be able to describe the optical security element according to the present invention more visually, the present invention is described below by way of example with reference to the exemplary optical security element shown in fig. 2, 3a and 3 b.

Fig. 2 is a schematic diagram of a top view of an exemplary optical security element according to another embodiment of the present invention, fig. 3a is a schematic diagram of a cross-sectional view of the optical security element shown in fig. 2 along the line X-X shown in fig. 2 according to another embodiment of the present invention, and fig. 3b is a schematic diagram of another cross-sectional view of the optical security element shown in fig. 2 along the line X-X shown in fig. 2 according to another embodiment of the present invention. The image portion "PY" in fig. 2 is a display region having an interference light variation plating layer, which corresponds to the first region a (including the first relief structure) in fig. 3a or 3 b. In general, the display area tends to present a pattern with special effects prepared with special optical microstructures (e.g. microstructures with rainbow holographic effect, sawtooth-shaped grating microstructures with dynamic effect)Like this. The background part in fig. 2 is a hollow-out region with a deplated layer, which has a transparent hollow-out feature when viewed in a perspective view, and corresponds to the second region b (including the second relief structure) in fig. 3a or fig. 3b, that is, an image formed by the boundary of the second region, that is, an image formed by the boundary of the second relief structure, can be presented when viewed in a transmission manner. Structurally, the optical security element shown in fig. 2 may have two layered structures as shown in fig. 3a and 3 b. The optical anti-counterfeiting element comprises a substrate 1, a relief structure layer 2, an interference light variable coating layer 3 positioned in a first area a and other functional coatings 4. The interference light variation coating layer 3 may have a five-layer structure as shown in fig. 3a, and specifically, a first partially transparent layer 31, a first dielectric layer 32, a reflective layer 33, a second dielectric layer 34, and a second partially transparent layer 35, which are sequentially stacked as shown in fig. 3 a. In the five-layer structure, the first and second partial transparent layers 31 and 35 may be composed of chromium, nickel, aluminum, silver, copper, tin, titanium, or an alloy thereof, the reflective layer 33 is composed of aluminum, silver, copper, tin, chromium, nickel, titanium, or an alloy thereof, and the first and second dielectric layers 32 and 34 are composed of MgF₂、SiO₂、ZnS、TiN、TiO₂、TiO、Ti₂O₃、Ti₃O₅、Ta₂O₅、Nb₂O₅、CeO₂、Bi₂O₃、Cr₂O₃、Fe₂O₃、HfO₂Or ZnO. In the interference light variation plating layer 3, the partially transparent layer provides a function of an absorption layer, and the light transmittance of each of the first and second partially transparent layers 31 and 35 is required to be less than 60%. The reflective layer provides light reflection and may be thicker, such as having a reflectivity greater than 90% and a transmissivity less than 10%. In order to obtain a hollowing effect, the first partially transparent layer 31 adjacent to the relief structure layer 2 is preferably aluminium or an aluminium alloy. Further, the interference light variation plating layer 3 may have a three-layer structure, specifically, a first partially transparent layer 31, a dielectric layer 36, and a second partially transparent layer 35, which are sequentially stacked, as shown in fig. 3 b. In the three-layer structure, the first and second partial transparent layers 31 and 35 may be made of chrome, nickel, aluminum, silver, copper, tin, titanium, or an alloy thereof, and the dielectric layer 36 is made of MgF₂、SiO₂、ZnS、TiN、TiO₂、TiO、Ti₂O₃、Ti₃O₅、Ta₂O₅、Nb₂O₅、CeO₂、Bi₂O₃、Cr₂O₃、Fe₂O₃、HfO₂Or ZnO. The first and second partially transparent layers 31, 35 need to function as both a reflective layer and an absorbing layer and thus can be neither too thick nor too thin. Generally, the light transmittance of the first and second partially transparent layers 31 and 35 is required to be greater than 30%, less than 60%, preferably greater than 35%, less than 45%. Also, in order to obtain the hollowing effect, the first partially transparent layer 31 adjacent to the relief structure layer 2 is preferably aluminum or an aluminum alloy. In addition, in the five-layer structure, the reflective layer may be thick (e.g., formed by evaporation), i.e., have high reflectance, so that colors represented on both sides of the interference light variation plating layer 3 including the five-layer structure have high brightness. In the three-layer structure, the partially transparent layers on both sides of the interference light variation plating layer 3 need to have functions of both a reflection layer and an absorption layer, and thus may not be too thick nor too thin, and thus the color brightness exhibited on both sides of the interference light variation plating layer 3 including the three-layer structure is poor. On the other hand, the three-layer structure is simple in manufacturing process and lower in cost. Therefore, the two modes have the advantages and the disadvantages respectively and are selected according to different application occasions. It should be noted that, in the description of fig. 3a and 3b, in the five-layer structure and the three-layer structure, the same reference numeral 31 is used to denote a first partially transparent layer and the same reference numeral 35 is used to denote a second partially transparent layer, and it is not meant to indicate that the first partially transparent layer and the second partially transparent layer included in the five-layer structure and the three-layer structure, respectively, are the same partially transparent layer and the same partially transparent layer.

In addition, the optical anti-counterfeiting element provided by the embodiment of the invention can be used as a label, a mark, a wide strip, a transparent window, a windowing safety line and the like to be applied to an optical anti-counterfeiting product, and especially can be used as a hot stamping mark to be applied to the optical anti-counterfeiting product.

In addition, another aspect of the embodiments of the present invention provides an optical anti-counterfeiting product, wherein the optical anti-counterfeiting product includes the optical anti-counterfeiting element described in the above embodiments.

In addition, the embodiment of the invention also provides a preparation method of the optical anti-counterfeiting element. Fig. 4 is a flowchart of a method for manufacturing an optical security element according to another embodiment of the present invention. As shown in fig. 4, the method includes the following steps.

In step S41, a transparent relief structure layer is formed on at least a partial region of the substrate, wherein the relief structure layer includes a relief structure. Wherein the substrate may be at least partially transparent or opaque. Where the optical security element comprises a substrate, the substrate is at least partially transparent; in the case where the optical security element does not include a substrate, the substrate may be at least partially transparent or may be opaque. For example, when the optical security element is placed on an optical security product, the substrate needs to be torn off, in which case there is no requirement for the transparency of the substrate, which may be at least partially transparent or opaque.

In step S42, an interference light variable plating layer is formed on at least a partial region of the relief structure layer, wherein the interference light variable plating layer exhibits an optically variable effect when viewed from both sides.

The relief structure layer enables the optical anti-counterfeiting element to show an image effect when being observed from two sides, and the interference light variable plating layer enables the optical anti-counterfeiting element to show an optical color-changing effect when being observed from two sides, so that the optical anti-counterfeiting element can simultaneously show the image effect and the optical color-changing effect when being observed from two sides, and the anti-counterfeiting performance of the optical anti-counterfeiting element is improved. The fluctuation structure layer comprises a first fluctuation structure and a second fluctuation structure, the interference light variable plating layer covers the first fluctuation structure, the optical anti-counterfeiting element has a partially hollow transparent effect when being observed in a transmission mode, and an image formed by the boundary of the second fluctuation structure can be presented. Therefore, the anti-counterfeiting dimension of the optical anti-counterfeiting element is increased, and the anti-counterfeiting performance of the optical anti-counterfeiting element is further improved.

The first relief structure and the second relief structure must satisfy the following condition: the aspect ratio of the first relief structure is smaller than the aspect ratio of the second relief structure, and/or the specific volume of the first relief structure is smaller than the specific volume of the second relief structure. The first relief structure and the second relief structure meet the conditions, so that when the optical anti-counterfeiting element is prepared, accurate hollowing is realized, namely, the interference light variable plating layer is accurately covered on the first relief structure. In addition, in the embodiments of the method for manufacturing an optical security element provided by the present invention, specific explanations regarding the aspect ratio and the volume ratio may be found in the explanations of the corresponding parts in the embodiments of the optical security element provided by the present invention.

Optionally, in an embodiment of the present invention, in a case where an aspect ratio of the first relief structure is smaller than an aspect ratio of the second relief structure, a specific volume of the first relief structure is smaller than a specific volume of the second relief structure, and an outermost layer of the interference light variation plating layer away from the first relief structure does not react with a corrosive atmosphere, forming the interference light variation plating layer on the first relief structure includes: forming an interference light variable coating on the relief structure layer, wherein the interference light variable coating at least covers the first relief structure; and placing the structure formed by the substrate, the relief structure layer and the interference light variable plating layer in the corrosion atmosphere until the interference light variable plating layer covered on the second area is completely or partially corroded; or forming an interference light variable coating on the relief structure layer, wherein the interference light variable coating at least covers the first relief structure; coating a coating on the interference light variation coating, wherein the coating at least covers the part of the interference light variation coating corresponding to the first photovoltaic structure, and the coating enables the interference light variation coating covering the first photovoltaic structure to be prevented from being corroded by a corrosive atmosphere; and placing the structure formed by the substrate, the relief structure layer and the interference light variable plating layer in a corrosion atmosphere until the interference light variable plating layer covered on the second area is completely or partially corroded.

Optionally, in an embodiment of the present invention, in a case where an aspect ratio of the first relief structure is smaller than an aspect ratio of the second relief structure, a specific volume of the first relief structure is larger than a specific volume of the second relief structure, and an outermost layer of the interference light variation plating layer away from the first relief structure does not react with a corrosive atmosphere, forming the interference light variation plating layer on the first relief structure includes: forming an interference light variable coating on the relief structure layer, wherein the interference light variable coating at least covers the first relief structure; and placing the structure formed by the substrate, the relief structure layer and the interference light variable plating layer in a corrosion atmosphere until the interference light variable plating layer covered on the second area is completely or partially corroded.

Optionally, in an embodiment of the present invention, in a case where an aspect ratio of the first relief structure is greater than an aspect ratio of the second relief structure, and/or an outermost layer of the interference light variation plating layer away from the first relief structure reacts with the corrosive atmosphere, a specific volume of the first relief structure is smaller than a specific volume of the second relief structure, and forming the interference light variation plating layer on the first relief structure includes: forming an interference light variable coating on the relief structure layer, wherein the interference light variable coating at least covers the first relief structure; coating a coating on the interference light variation coating, wherein the coating at least covers the part of the interference light variation coating corresponding to the first photovoltaic structure, and the coating enables the interference light variation coating covering the first photovoltaic structure to be prevented from being corroded by a corrosive atmosphere; and placing the structure formed by the substrate, the relief structure layer and the interference light variable plating layer in a corrosion atmosphere until the interference light variable plating layer covered on the second area is completely or partially corroded.

Optionally, in an embodiment of the present invention, the interference light variation plating layer includes a first partially transparent layer, a first dielectric layer, a reflective layer, a second dielectric layer, and a second partially transparent layer, which are sequentially stacked. Preferably, the first partially transparent layer is different from the second partially transparent layer and/or the first dielectric layer is different from the second dielectric layer.

Optionally, in an embodiment of the present invention, the interference light variation plating layer includes a first partially transparent layer, a dielectric layer, and a second partially transparent layer, which are sequentially stacked. Preferably, the first partially transparent layer is different from the second partially transparent layer.

Optionally, in an embodiment of the present invention, the preparation method further includes: after the interference light variable coating is formed, a protective layer and/or a functional coating is formed on the side of the optical anti-counterfeiting element opposite to the substrate. The protective layer and/or functional coating may be a single layer or a plurality of layers. The protective layer and/or functional coating generally has a protective effect to protect the interference light variable coating from corrosion by external conditions in the use environment, and also generally has an effect of bonding with other substrates, such as paper. Further, in the case where the optical security element includes both the protective layer and the functional coating layer, the functional coating layer is formed on the protective layer.

In the embodiment of the method for manufacturing the optical anti-counterfeiting element provided by the invention, for the specific explanation of the interference light variable-plating layer, reference may be made to the explanation of the corresponding part in the embodiment of the optical anti-counterfeiting element provided by the invention.

The following describes an exemplary method for manufacturing an optical security element according to an embodiment of the present invention, with reference to fig. 5 to 7, by taking the optical security element corresponding to the cross-sectional view shown in fig. 3a as an example. In this embodiment, the method may include the following, among others.

In step S1, a relief structure layer 2 is formed on the substrate 1, as shown in fig. 5.

The substrate 1 may be opaque, at least partially transparent, or a colored dielectric layer, or a transparent dielectric film with a functional coating (such as an adhesion enhancement layer) on the surface, or a composite multilayer film. When the optical security element comprises a substrate 1, the substrate 1 is at least partially transparent so that it can be viewed on both sides; when the optical security element does not comprise the substrate 1, for example, when the optical security product is placed, the substrate 1 needs to be torn off, and then the substrate 1 may be transparent or opaque. The substrate 1 is generally formed of a film material having good chemical resistance and high mechanical strength, and for example, a flexible substrate may be formed of a plastic film such as a polyethylene terephthalate (PET) film, a polyethylene naphthalate (PEN) film, or a polypropylene (PP) film, and the substrate is preferably formed of a PET material.

The relief structure layer 2 has the property of being able to deform at a certain temperature and pressure to form the desired relief structure. Undulation structure layer2 may be selected from thermoplastic materials and also radiation curable materials. The relief structure layer 2 has a first region a and a second region b, wherein the aspect ratio of the first relief structures located in the first region a is smaller than the aspect ratio of the surface of the second relief structures located in the second region b, and/or the specific volume of the first relief structures located in the first region a is smaller than the specific volume of the second relief structures located in the second region b. As far as the specific shape of the relief structure is concerned, the cross-section of the first relief structure and/or the second relief structure may be a cosine structure, a sawtooth structure, a cylindrical structure, a spherical structure, a pyramid structure, a square wave structure, or a combination thereof. Wherein the first photovoltaic structure provides a particular optical effect, as desired; since the second relief structure is usually only used to achieve the deplating hollowing and does not exhibit a special optical effect, a sawtooth grating with sharp tops is preferred. The first relief structure and the second relief structure may be wholly or partially periodic structures with a period greater than 1um and less than 20 um. Generally, the aspect ratio of the first relief structure is less than 0.3, and the aspect ratio of the second relief structure is greater than 0.3, and preferably, the aspect ratio of the first relief structure is less than 0.2, and the aspect ratio of the second relief structure is greater than 0.5. Alternatively, the first photovoltaic structure has a specific volume of less than 1um³/um²The specific volume of the second undulation structure is more than 1um³/um²Preferably, the specific volume of the first photovoltaic structure is less than 0.5um³/um²The specific volume of the second relief structure is more than 1.5um³/um²。

In step S2, the interference light variable plating layer 3 is formed on the surface of the relief structure layer 2. For example, the interference light variable plating layer 3 is formed on the surface of the relief structure layer 2 by vapor deposition. As shown in fig. 6. The interference light variation coating 3 provides an optical effect of double-sided observation. The interference light variation coating 3 includes a five-layer structure, which is a first partially transparent layer 31, a first dielectric layer 32, a reflective layer 33, a second dielectric layer 34, and a second partially transparent layer 35 sequentially stacked, wherein the first partially transparent layer 31 is adjacent to the relief structure layer 2, as shown in fig. 6. The first and second partially transparent layers 31 and 35 may be made of chrome, nickel, aluminum, silver, copper, tin, titanium, or alloys thereofThe reflective layer 33 is made of aluminum, silver, copper, tin, chromium, nickel, titanium, or an alloy thereof, and the first dielectric layer 32 and the second dielectric layer 34 are made of MgF₂、SiO₂、ZnS、TiN、TiO₂、TiO、Ti₂O₃、Ti₃O₅、Ta₂O₅、Nb₂O₅、CeO₂、Bi₂O₃、Cr₂O₃、Fe₂O₃、HfO₂Or ZnO. In the interference light variation plating layer 3, the partially transparent layer provides a function of an absorption layer, and the light transmittance of each of the first and second partially transparent layers 31 and 35 is required to be less than 60%. The reflective layer provides light reflection and may be thicker, such as having a reflectivity greater than 90% and a transmissivity less than 10%. In order to obtain a hollowing effect, the first partially transparent layer 31 adjacent to the relief structure layer 2 is preferably aluminium or an aluminium alloy.

The interference light variation plating layer 3 may have a three-layer structure, which may be specifically a first partially transparent layer 31, a dielectric layer 36, and a second partially transparent layer 35, which are sequentially stacked, as shown in fig. 3 b. The first and second partially transparent layers 31 and 35 may be composed of chromium, nickel, aluminum, silver, copper, tin, titanium, or alloys thereof, and the dielectric layer 36 is composed of MgF₂、SiO₂、ZnS、TiN、TiO₂、TiO、Ti₂O₃、Ti₃O₅、Ta₂O₅、Nb₂O₅、CeO₂、Bi₂O₃、Cr₂O₃、Fe₂O₃、HfO₂Or ZnO. The first and second partially transparent layers 31, 35 need to function as both a reflective layer and an absorbing layer and thus can be neither too thick nor too thin. Generally, the light transmittance of the first and second partially transparent layers 31 and 35 is required to be greater than 30%, less than 60%, preferably greater than 35%, less than 45%. Also, in order to obtain the hollowing effect, the first partially transparent layer 31 adjacent to the relief structure layer 2 is preferably aluminum or an aluminum alloy.

In addition, the interference light variation coating is generally formed by a vapor deposition method, and when the interference light variation coating is formed by the vapor deposition method, the interference light variation coating and the relief structure layer can be covered in the same type, that is, the surface shape of the interference light variation coating is the same as or basically the same as the surface shape of the relief structure layer.

S3, placing the above structure (the structure formed by the substrate 1, the relief structure layer 2 and the interference light variable plating layer 3) in a certain corrosive atmosphere capable of reacting with one or more plating materials in the interference light variable plating layer 3 until the interference light variable plating layer 3 in the second area is completely or partially corroded.

If the aspect ratio of the first relief structure is smaller than that of the second relief structure, the outermost plating layer (such as the second partially transparent layer 35 shown in fig. 3a or the second partially transparent layer 35 shown in fig. 3 b) of the interference light variable plating layer 3 does not react with the etching atmosphere, and the specific volume of the first relief structure is larger than that of the second relief structure, the step S2 may be directly followed by the step S3. This is because, if the aspect ratio of the first relief structure is smaller than that of the second relief structure, after the interference light variation plating layer is formed on the relief structure layer 2 (for example, by vapor deposition), the interference light variation plating layer in the first region is relatively dense, the interference light variation plating layer in the second region is relatively loose, and the outermost plating layer of the interference light variation plating layers does not react with the corrosive atmosphere, and the outermost plating layer of the interference light variation plating layers in the first region can protect the other plating layers, and therefore, after the step S3 is performed, the interference light variation plating layer accurately located in the first region can be obtained. For example, the first undulation structure has an aspect ratio of 0.1, the second undulation structure has an aspect ratio of 0.4, and the interference light variation plating layer 3 has a five-layer structure, which is sequentially Al_{Thin sheet}/SiO₂/Al_{Is thick and thick}/SiO₂and/Cr, the corrosive atmosphere is acid liquor or alkali liquor. Because the aspect ratio of the first undulation structure is smaller than that of the second undulation structure, after evaporation, the interference light variation plating layer of the first area is compact, the interference light variation plating layer of the second area is relatively loose, acid liquor or alkali liquor reacts with aluminum through other plating layers of the second area, and other plating layers of the second area are simultaneously stripped; the first region outer plating Cr can be used for other inner platingTo achieve the protection effect. Therefore, after the step of S3 is performed, the interference light variable plating layer precisely located in the first area can be obtained, as shown in fig. 7.

If the aspect ratio of the first relief structure is smaller than that of the second relief structure, and the outermost plating layer (such as the second partially transparent layer 35 shown in fig. 3a or the second partially transparent layer 35 shown in fig. 3 b) of the interference light variable plating layer 3 is not reactive to the etching atmosphere, and the specific volume of the first relief structure is smaller than that of the second relief structure, the step S2 may be directly followed by the step S3, as described above. In addition, if the aspect ratio of the first relief structure is smaller than that of the second relief structure, the outermost plating layer (such as the second partially transparent layer 35 shown in fig. 3a or the second partially transparent layer 35 shown in fig. 3 b) of the interference light variable plating layer 3 does not react with the etching atmosphere, and the specific volume of the first relief structure is smaller than that of the second relief structure, a coating 5 may be applied on the interference light variable plating layer after the step S2 and before the step S3, as shown in fig. 8. The coating 5 can provide effective protection for the interference light variation coating of the first relief structure so as to protect the interference light variation coating of the first relief structure from the corrosion atmosphere in the step S3, and the coating 5 cannot provide effective protection for the interference light variation coating of the second relief structure so as to enable the interference light variation coating of the second relief structure to be totally or partially corroded by the corrosion atmosphere in the step S3. Therefore, after the step of S3 is performed, the interference light variable plating layer precisely located in the first area can be obtained.

If the aspect ratio of the first relief structure is larger than that of the second relief structure and/or the outermost plating layer of the interference light variation plating layer (such as the second partially transparent layer 35 shown in fig. 3a or the second partially transparent layer 35 shown in fig. 3 b) reacts with the etching atmosphere in step S3, the specific volume of the first relief structure must be smaller than that of the second relief structure, and after step S2 and before step S3, a coating 5 process is applied on the interference light variation plating layer, as shown in fig. 8. This is because, due to the difference in specific volume between the two relief structures, after the step of applying the coating 5, the coating 5 can provide the interference light variable layer of the first relief structure with the interference light variable layerFor effective protection of the interference light variation coating of the first relief structure from the corrosion atmosphere in step S3, while this coating 5 is not able to provide effective protection of the interference light variation coating of the second relief structure, so that the interference light variation coating of the second relief structure is totally or partially corroded by the corrosion atmosphere in step S3. Therefore, after the step of S3 is performed, the interference light variable plating layer precisely located in the first area can be obtained. For example, the first photovoltaic structure has an aspect ratio of 0.3 and a specific volume of 0.5um³/um²The second undulation structure has an aspect ratio of 0.2 and a specific volume of 1.5um³/um²The interference light variable coating layer has a five-layer structure and is sequentially Al_{Thin sheet}/SiO₂/Al_{Is thick and thick}/SiO₂/Al_{Thin sheet}The corrosive atmosphere is acid liquor or alkali liquor. In this case, it is necessary to apply the coating 5 of a certain thickness before the step of S3 is performed, as shown in fig. 8. Due to the difference of the specific volume of the two relief structures, the thickness of the coating can be selected, so that the interference light variable coating of the first relief structure can be effectively protected, and the interference light variable coating of the second relief structure cannot be effectively protected. Thus, after the step of S3 is performed, the interference light variable plating layer 3 precisely located in the first area can be obtained, as shown in fig. 9. In addition, the coating layer is generally formed by coating a liquid material and then drying, so that the coating layer and the interference light variation plating layer/relief structure layer are covered differently, that is, the surface shape of the coating layer is obviously different from that of the interference light variation plating layer/relief structure layer, and the coating layer tends to be surface-flattened.

Based on the above principle, in order to obtain the plating layer located exactly in the first region, there may be 8 cases as follows (where "√" represents a plating layer located exactly in the first region can be achieved, and "x" represents a plating layer located exactly in the first region cannot be achieved) depending on the difference in the aspect ratio, the specific volume of the microstructures (i.e., the first undulating structure and the second undulating structure) of the first region and the second region, and whether or not the outermost plating layer of the interference light variation plating layer can react with the corrosive atmosphere. According to different situations, different hollow-out modes can be implemented, namely whether a coating process needs to be applied between the step S2 and the step S3. Meanwhile, in some cases (such as cases 4, 7 and 8), no matter what type of hollow-out method is adopted, the multilayer interference coating precisely located in the first area cannot be obtained.

Because the second relief structure is usually only used for realizing the hollow-out requirement of the interference-free light variable plating layer and does not show a special optical effect, the depth-to-width ratio and the specific volume of the second relief structure are designed to be as large as possible.

Therefore, the preparation method of the optical anti-counterfeiting element provided by the embodiment of the invention realizes the optical effect of integrating the double-sided interference optical variable characteristic and the precise hollow, namely the prepared optical anti-counterfeiting element can simultaneously show the optical color change effect and the image effect when being observed from two sides and can show the transmission image when being observed in a transmission way.

Optionally, in an embodiment of the present invention, the method for preparing an optical anti-counterfeiting element may further include the following steps: after the interference light variation plating layer is formed on the first relief structure, a protective and/or functional coating 4 is coated on the optical security element, as shown in fig. 3a or fig. 3 b. The protective layer and/or functional coating may be a single layer or a plurality of layers. The protective and/or functional coating generally provides protection from the environment in which it is used, while generally providing adhesion to other substrates, such as paper. Further, in the case where the optical security element includes both the protective layer and the functional coating layer, the functional coating layer is formed on the protective layer.

In addition, the preparation method of the optical anti-counterfeiting element provided by the embodiment of the invention is suitable for manufacturing labels, marks, wide strips, transparent windows, windowed safety lines and the like, and is particularly suitable for manufacturing hot stamping marks.

In summary, the relief structure layer makes the optical anti-counterfeiting element present the image effect when being observed from both sides, and the interference light becomes cladding material and makes the optical anti-counterfeiting element present the optical discoloration effect when being observed from both sides, so, realized making the optical anti-counterfeiting element homoenergetic present image effect and optical discoloration effect simultaneously when being observed from both sides, improved the anti-counterfeiting performance of optical anti-counterfeiting element. Furthermore, the optical security element may also present an image formed by the boundaries of the second relief structure when viewed in transmission. Therefore, the anti-counterfeiting dimension of the optical anti-counterfeiting element is increased, and the anti-counterfeiting performance of the optical anti-counterfeiting element is further improved.

Although the embodiments of the present invention have been described in detail with reference to the accompanying drawings, the embodiments of the present invention are not limited to the details of the above embodiments, and various simple modifications can be made to the technical solutions of the embodiments of the present invention within the technical idea of the embodiments of the present invention, and the simple modifications all belong to the protection scope of the embodiments of the present invention.

It should be noted that the various features described in the above embodiments may be combined in any suitable manner without departing from the scope of the invention. In order to avoid unnecessary repetition, the embodiments of the present invention do not describe every possible combination.

In addition, any combination of various different implementation manners of the embodiments of the present invention is also possible, and the embodiments of the present invention should be considered as disclosed in the embodiments of the present invention as long as the combination does not depart from the spirit of the embodiments of the present invention.