WO2021057574A1

WO2021057574A1 - Multilayer body optical anti-counterfeiting element and fabrication method therefor

Info

Publication number: WO2021057574A1
Application number: PCT/CN2020/115557
Authority: WO
Inventors: 胡春华; 孙凯; 张宝利; 朱军
Original assignee: 中钞特种防伪科技有限公司; 中国印钞造币总公司
Priority date: 2019-09-29
Filing date: 2020-09-16
Publication date: 2021-04-01
Also published as: EP4035903A1; EP4035903A4; CN112572018B; CN112572018A; EP4035903B1; JP2022551240A; JP7307853B2

Abstract

Provided are an optical anti-counterfeiting element and a fabrication method therefor. The optical anti-counterfeiting element comprising: an undulating structure layer (2), which comprises: a first region (A) having a first microstructure and a second region (B) having a second microstructure, the specific volume of the second microstructure being greater than the specific volume of the first microstructure; and a first plating layer (31), a dielectric layer (32), a second plating layer (33) and a protective layer (4) which are sequentially stacked on one side of the undulating structure layer (2), the first plating layer (31) and the dielectric layer (32) being located in the first region (A) and the second region (B), while the second plating layer (33) and the protective layer (4) are located in the first region (A) but not in the second region (B). The first plating layer (31), the dielectric layer (32) and the second plating layer (33) constitute a functional plating layer group (3), and the functional plating layer group (3) and the first microstructure have combined optical features in the first region (A), and the first plating layer (31) and the second microstructure have combined optical features in the second region (B).

Description

Multilayer optical anti-counterfeiting element and manufacturing method thereof

Technical field

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

Background technique

In order to prevent counterfeiting by means of scanning and copying, optical anti-counterfeiting technology is widely used in various high-security or high-value-added printed materials such as banknotes, credit cards, passports, securities and product packaging, and has achieved very good results.

In various optical anti-counterfeiting technologies, the optical effects formed by microstructures, including diffraction and non-diffraction, have been widely used due to their high brightness and obvious dynamic effects. In order to increase the brightness of the image, the micro-structure optical anti-counterfeiting technology generally uses a metal reflective layer, such as aluminum. Among them, the most extensive optical anti-counterfeiting technology currently applied to optical films-holographic technology is an optical technology developed by using the diffraction effect formed by microstructures. The fifth set of 1999 version of 5 yuan, 10 yuan, 20 yuan, 50 yuan, 100 yuan of anti-counterfeiting lines uses holographic technology. In addition, the technology of multi-layer functional coating sets has attracted more and more attention because of its strong optical discoloration effect under different viewing angles, or the obvious discoloration effect of reflection and transmission observation. The former is generally referred to as multilayer interference optical variable technology. The classic multilayer interference coating generally adopts a sandwich Fabero interference cavity structure composed of a reflective layer, a dielectric layer and an absorbing layer. The reflective layer is generally made of high-brightness metal materials, the dielectric layer is generally made of transparent inorganic or organic materials, and the absorption layer is also called a semi-transparent layer, which is generally made of thinner metal materials with good absorption. The fifth set of the 2015 version of the 100 yuan security thread uses multi-layer interference optical variable technology, which is magenta when viewed from the front and green when viewed obliquely.

If the optical microstructure and the high-brightness metal reflective layer feature and the multi-layer functional coating group feature are integrated into the same optical anti-counterfeiting element, the optical anti-counterfeiting effect can be greatly enhanced. Patent application CN 200980104829.3 proposes to realize the preparation of optical anti-counterfeiting products integrating multilayer interference optical variable coating and high-brightness metal reflective layer through partial printing hollowing process, that is, some areas have multilayer interference optically variable characteristics, and some areas have high-brightness metal The reflective layer has optical characteristics; and further, other areas have a perspective hollowing effect. However, the mutual registration accuracy of the three areas in the patent application depends on the accuracy of printing, and the accuracy of printing is generally above 100um, which limits the application of high-end anti-counterfeiting optical products to a certain extent.

Therefore, it is of great significance to produce an optical anti-counterfeiting element that simultaneously has the characteristics of a high-brightness metal reflective layer, a multi-layer interference optical variable, and the positioning of the two characteristic regions with zero error. Further, if the optical anti-counterfeiting element further integrates hollow features, and the hollow area and the image area are also positioned with zero error, the anti-counterfeiting performance of the product will be further improved.

Summary of the invention

The purpose of the present invention is to provide a multilayer optical anti-counterfeiting element and a manufacturing method thereof. When viewed from the first side or/and second side of the optical anti-counterfeiting element, the product with the high-brightness metal reflective layer and the multi-layer functional coating (especially the interference optical variable coating) feature at the same time, then the product with the optical anti-counterfeiting element has Excellent comprehensive integrated anti-counterfeiting performance. Further, if the optical anti-counterfeiting element further integrates hollow features, and the hollow area and the image area are also positioned with zero error, the anti-counterfeiting performance of the product will be further improved.

In order to achieve the above objective, an embodiment of the present invention provides an optical anti-counterfeiting element. Structurally, the optical anti-counterfeiting element contains a substrate, and the first side of the substrate has an undulating structure layer, and the undulating structure layer includes a first The first area of the microstructure and the second area with the second microstructure, the specific volume of the second microstructure is greater than the specific volume of the first microstructure; one side of the undulating structure layer has a first layer stacked in sequence. Plating layer, dielectric layer, second plating layer and protective layer; the first plating layer and the dielectric layer are located in the first area and located in the second area, the second plating layer and the protective layer are located in the The first area is not located in the second area; wherein, the first plating layer, the dielectric layer, and the second plating layer constitute a functional plating layer group, and the functional plating layer group and the first microstructure are in The first area has a combined optical feature, and the first plating layer and the second microstructure have a combined optical feature in the second area. Since the two image regions (the first region and the second region) presented by reflection observation are determined by the microstructure, they have the feature of zero positioning error.

The specific volume of the undulating structure mentioned here refers to the ratio of the undulating structure layer in a horizontal state, assuming that the volume of the liquid that just completely covers the surface of the undulating structure to the projected area of the undulating structure on the horizontal plane; the present invention also relates to another important point The physical quantity, that is, the aspect ratio of the undulating structure, it refers to the ratio of the depth to the width (or the period of the periodic structure) of the undulating structure; according to this definition, the aspect ratio is a dimensionless physical quantity, and the dimension of the specific volume is um ³ /um ² ; According to this definition, a flat structure is regarded as an undulating structure with zero aspect ratio and zero specific volume; aspect ratio and specific volume are two physical quantities that are not directly related in quantity; for example, The structure A is a one-dimensional zigzag grating with a depth of 1um and a period of 1um, and its aspect ratio is 1, and the specific volume is 0.5um ³ /um ² ; the structure B is a one-dimensional zigzag grating with a depth of 2um and a period of 4um. The aspect ratio is 0.5 and the specific volume is 1um ³ /um ² ; that is, the aspect ratio of the A structure is greater than that of the B structure, and the specific volume of the B structure is greater than the specific volume of the A structure; the first microstructure The difference between the specific volume and the second microstructure is the basis for the removal of the second coating material layer in the second area; the precise removal of the coating on the specific microstructure based on the difference in specific volume will be further explained in the specific implementation section .

Generally, the first microstructure or the second microstructure is a periodic structure or a structure or a combination structure in a periodic structure; the cross-sectional structure of the first microstructure or the second microstructure It is a sinusoidal structure, a rectangular grating structure, a trapezoidal grating structure, a blazed grating structure, and an arc-shaped grating structure, or a combined structure composed of at least any two structures.

Preferably, the specific volume of the first microstructure is greater than or equal to 0um ³ /um ² and less than 0.5um ³ /um ² ; the specific volume of the second microstructure is greater than 0.4um ³ /um ² and less than 3um ³ /um ² .

Preferably, the first plating layer is adjacent to the undulating structure layer.

Preferably, the material of the first plating layer or the second plating layer is any one of nickel, chromium, aluminum, silver, copper, tin, and titanium or an alloy composed of a combination of at least any two metals; the dielectric The material of the layer is magnesium fluoride, silicon dioxide, zinc sulfide, titanium nitride, titanium dioxide, titanium monoxide, titanium trioxide, titanium pentoxide, tantalum pentoxide, niobium pentoxide, cerium dioxide, three Any one compound of bismuth oxide, chromium oxide green, iron oxide, hafnium oxide and zinc oxide or a mixture of at least any two compounds.

Preferably, the functional coating group is a multi-layer interference optically variable coating, and the optical anti-counterfeiting element on any side of the multi-layer interference optically variable coating has the characteristic of interference optically variable.

Further, in order to allow the product to have a hollow feature for precise positioning, at this time, the undulating structure layer further includes a third region having a third microstructure, and the aspect ratio of the third microstructure is greater than that of the second microstructure. The aspect ratio of the structure, and the specific volume of the third microstructure is greater than the specific volume of the first microstructure; the first plating layer and the second plating layer are not located in the third area; the optical anti-counterfeiting The element has a hollow feature in the third area. The difference between the specific volume of the third microstructure and the first microstructure and the difference in the aspect ratio between the third microstructure and the second microstructure are the basis for achieving the removal of both the first plating layer and the second plating layer in the third region. The precise removal of the coating on a specific microstructure based on the difference in aspect ratio will be further elaborated in the specific implementation section. Preferably, the aspect ratio of the third microstructure is greater than 0.2 and less than 1; the aspect ratio of the second microstructure is greater than 0 and less than 0.3; the specific volume of the third microstructure is greater than 0.4um ³ /um ² , less than 3um ³ /um ² .

The embodiment of the present invention also provides a manufacturing method of an optical anti-counterfeiting element, the manufacturing method including:

S1) forming an undulating structure layer, wherein the undulating structure layer includes a first region having a first microstructure and a second region having a second microstructure, and the specific volume of the second microstructure is larger than that of the first microstructure. The specific volume of the structure;

S2) sequentially forming a laminated first plating material layer, a dielectric layer material layer, a second plating material layer, and a protective layer material layer on one side of the undulating structure layer;

S3) The semi-finished product of step S2) is placed in an atmosphere capable of reacting with the second plating material layer until part or all of the second plating material layer in the second area is removed, and only in the At least a laminated first plating layer and a second plating layer are left in the first area, wherein the first plating layer and the second plating layer are the first plating layer material layer and the second plating layer material layer located in the Part of the plating material layer in the first area that has not been removed.

Preferably, the undulating structure layer in step S1) further includes a third region having a third microstructure, the aspect ratio of the third microstructure is greater than the aspect ratio of the second microstructure, and the third microstructure The specific volume of the structure is greater than the specific volume of the first microstructure.

Preferably, the manufacturing method further includes: S4) placing the semi-finished product of step S3) in an atmosphere capable of reacting with the first plating material layer until the first plating material layer and the second plating layer located in the third area The material layer is partially or completely removed.

Preferably, the first plating layer or/and the second plating layer in step S3) contains an aluminum layer;

In step S3), the atmosphere capable of reacting with the first coating material layer or/and the second coating material layer is selected from an acid solution and/or an alkali solution.

Preferably, the manufacturing method further includes: applying an inorganic or organic plating or coating process to realize other optical anti-counterfeiting functions or auxiliary functions.

Other features and advantages of the embodiments of the present invention will be described in detail in the following specific implementation section.

Description of the drawings

The accompanying drawings are used to provide a further understanding of the embodiments of the present invention, and constitute a part of the specification. Together with the following specific implementations, they are used to explain the embodiments of the present invention, but do not constitute a limitation to the embodiments of the present invention. In the attached picture:

Fig. 1 is a top view of a first exemplary optical anti-counterfeiting element according to an embodiment of the present invention;

Fig. 2 is a possible cross-sectional view of the first exemplary optical anti-counterfeiting element in the X-X direction according to the embodiment of the present invention;

3 is a cross-sectional view of an exemplary element after the undulating structure layer is formed in the process of manufacturing the first exemplary optical anti-counterfeiting element according to the embodiment of the present invention;

4 is a cross-sectional view of an exemplary element after a functional coating group is formed in the process of manufacturing the first exemplary optical anti-counterfeiting element according to an embodiment of the present invention;

5 is a cross-sectional view of an exemplary element after a protective layer is formed in the process of manufacturing the first exemplary optical anti-counterfeiting element according to an embodiment of the present invention;

FIG. 6 is a cross-sectional view of an exemplary element after a corrosive atmosphere in the process of manufacturing the first exemplary optical anti-counterfeiting element according to an embodiment of the present invention;

Fig. 7 is a top view of a second exemplary optical anti-counterfeiting element according to an embodiment of the present invention;

FIG. 8 is a possible cross-sectional view of the second exemplary optical anti-counterfeiting element according to the embodiment of the present invention along the X-X direction;

9 is a cross-sectional view of an exemplary element after the undulating structure layer is formed in the process of manufacturing the second exemplary optical anti-counterfeiting element according to the embodiment of the present invention;

10 is a cross-sectional view of an exemplary element after a functional coating group is formed in the process of manufacturing a second exemplary optical anti-counterfeiting element according to an embodiment of the present invention;

11 is a cross-sectional view of an exemplary element after a protective layer is formed in the process of manufacturing a second exemplary optical anti-counterfeiting element according to an embodiment of the present invention;

FIG. 12 is a cross-sectional view of an exemplary element after undergoing a corrosive atmosphere in the process of manufacturing a second exemplary optical anti-counterfeiting element according to an embodiment of the present invention.

Description of Reference Signs

1 Base material 2 undulating structure layer

31 First coating layer 32 Dielectric layer

33 Second Coating Layer 3 Functional Coating Group

4 Protection layer

5 Other functional coatings

detailed description

The specific implementation manners of the embodiments of the present invention will be described in detail below in conjunction with the drawings. It should be understood that the specific implementations described here are only used to illustrate and explain the embodiments of the present invention, and are not used to limit the embodiments of the present invention.

Example one

As shown in Figure 1, the optical anti-counterfeiting element contains a first area A and a second area B. The first area A has the optical characteristics of the combination of the first optical microstructure and the functional coating group, and the second area B has the second optical microstructure and the second area. The optical characteristics of a coating combination. The two areas are strictly positioned to each other. The local lines of the image can be very fine, for example, less than 50um. Typically, the functional coating group is a multilayer interference optically variable coating, and the first coating is a metal reflective coating (such as an aluminum layer). In this way, the first area A exhibits interference optically variable characteristics, and the second area B exhibits ordinary metal reflective coating characteristics.

As shown in FIG. 2, the optical anti-counterfeiting element includes a substrate 1, an undulating structure layer 2, a first plating layer 31, a dielectric layer 32, a second plating layer 33, a protective layer 4, and other functional coatings 5. The first plating layer 31, the dielectric layer 32, and the second plating layer 33 constitute the functional plating layer group 3. The substrate 1 and the relief structure layer 2 are usually made of transparent materials. The undulating structure layer 2 includes a first area A composed of a first microstructure and a second area B composed of a second microstructure. The specific volume of the second microstructure is greater than the specific volume of the first microstructure. . The first area A is provided with a functional plating layer group 3 composed of a first plating layer 31, a dielectric layer 32, and a second plating layer 33, and the second area B is provided with a first plating layer 31 and a dielectric layer 32. Generally, the dielectric layer 32 is a colorless and transparent material, and does not provide a special optical effect in the second region B. Viewed from above or/and below the anti-counterfeiting element, the first area A presents the optical characteristics of the combination of the first microstructure and the functional coating group 3, and the second area B presents the optical characteristics of the combination of the second microstructure and the first coating 31. If the first plating layer 31 is semi-transparent and the second plating layer 33 is opaque or substantially opaque, the optical security element must be viewed from below; if the first plating layer 31 is opaque or substantially opaque, and the second plating layer 33 is semi-transparent, the optical security element must Viewed from above; if the first plating layer 31 and the second plating layer 33 are both translucent, the optical anti-counterfeiting element can be viewed from below or from above. The protective layer 4 is adjacent to the functional plating layer group 3. The protective layer 4 is a natural product in the manufacturing process and generally does not provide additional optical effects. In particular, in the first area A, the first plating layer 31, the dielectric layer 32, and the second plating layer 33 serve as the reflective layer, the dielectric layer, and the absorbing layer, respectively, and combine to form a group of multilayer interference optical variable plating layers, namely the first A region A has an anti-counterfeiting feature combining the first microstructure and a multi-layer interference optical variable coating; and the second region B has an anti-counterfeiting feature combining the second microstructure and the traditional reflective layer. Other functional coatings 5 can be set as required, for example, an adhesive layer that serves as an adhesion to the main product to be protected.

The method for preparing the optical anti-counterfeiting element shown in FIG. 2 according to the present invention will be described below in conjunction with FIG. 3 to FIG. 6. The method includes steps S1 to S4. For the sake of brevity of description, the functional coating group 3 is selected as a multi-layer interference optical variable coating, and the first coating 31, the dielectric layer 32, and the second coating 33 serve as the reflective layer, the dielectric layer, and the absorbing layer, respectively.

S1. An undulating structure layer 2 is formed on the first side surface of the substrate 1. The undulating structure layer 2 includes at least a first area A composed of a first microstructure and a second area B composed of a second microstructure. The specific volume of the second microstructure is greater than the specific volume of the first microstructure, as shown in FIG. 3.

The substrate 1 may be at least partially transparent, or a colored dielectric layer, or a transparent dielectric film with a functional coating on the surface, or a multi-layer film formed by compounding. The substrate 1 is generally formed of a film material with good physical and chemical resistance and high mechanical strength. For example, polyethylene terephthalate (PET) film, polyethylene naphthalate (PEN) film, and polyethylene terephthalate (PEN) film can be used. A plastic film such as a propylene (PP) film forms the base material 1, and the base material 1 is preferably formed of a PET material. The substrate 1 may contain an adhesion enhancement layer to enhance the adhesion of the substrate 1 and the undulating structure layer 2. The base material 1 may also contain a release layer to realize the separation of the final product base material 1 and the relief structure layer 2.

The undulating structure layer 2 can be formed by batch replication through processing methods such as ultraviolet casting, molding, and nanoimprinting. For example, the undulating structure layer 2 can be formed from a thermoplastic resin through a molding process, that is, the thermoplastic resin pre-coated on the substrate 1 is heated and softened and deformed when passing through a high-temperature metal template, thereby forming a specific undulating structure, and then cooling and molding . The undulating structure layer 2 can also be formed by a radiation curing casting process, that is, by coating a radiation curing resin on the substrate 1 and pressing the original plate on it, while irradiating radiation such as ultraviolet rays or electron beams to cure the above materials, Then, the original plate is removed to form the relief structure layer 2.

In order to achieve the subsequent removal of the plating layer, the specific volume of the second microstructure is greater than the specific volume of the first microstructure. Preferably, the specific volume of the first microstructure is greater than or equal to 0um ³ /um ² and less than 0.5um ³ /um ² , and the specific volume of the second microstructure is greater than 0.4um ³ /um ² and less than 3um ³ /um ² .

The first microstructure or the second microstructure is a periodic structure or a structure or a combination structure of the periodic structure; the cross-sectional structure of the first microstructure or the second microstructure is a sinusoidal structure Any one structure, rectangular grating structure, trapezoidal grating structure, blazed grating structure and arc-shaped grating structure, or a combined structure composed of at least any two structures. The size and lateral arrangement of the first and second microstructures are determined by the required optical effects. The first microstructure can be selected as a flat structure.

S2, forming a functional plating layer group 3 composed of a first plating layer 31 material layer, a dielectric layer 32 material layer, and a second plating layer 33 material layer on the undulating structure layer 2, as shown in FIG. 4.

In this embodiment, the functional coating group 3 is selected as a multi-layer interference optically variable coating, and the first coating 31, the dielectric layer 32, and the second coating 33 respectively serve as the reflective layer, the dielectric layer, and the absorbing layer, that is, the first coating 31 is Opaque or substantially opaque, and the second plating layer 33 is semi-transparent.

The function of the first plating layer 31 is to serve as a reflective layer in the interference optically variable plating layer. The material of the first plating layer 31 may be any one of Al, Cu, Ni, Cr, Ag, Fe, Sn, Au, and Pt, a mixture or an alloy of at least two metals. The thickness of the first plating layer 31 is generally selected to be greater than 10 nm and less than 80 nm, preferably greater than 20 nm and less than 50 nm. If the metal reflective coating is too thin, the brightness will be insufficient; if the metal reflective coating is too thick, the fastness to the undulating structure layer will be poor, and the cost will increase. The first plating layer 31 can generally be formed on the undulating structure layer 2 by physical and/or chemical vapor deposition methods, such as but not limited to thermal evaporation, magnetron sputtering, MOCVD and the like. Preferably, the first plating layer 31 is formed on the undulating structure layer 2 with a uniform surface density and in a manner of homogenous coverage.

The dielectric layer 32 functions as a dielectric layer in the Fabero interference cavity. The dielectric layer 32 is generally formed by a vapor deposition method, and the material can be selected from MgF ₂ , Sn, Cr, ZnS, ZnO, TiO ₂ , MgO, SiO ₂ or a mixture thereof. After the vapor deposition, the surface morphology of the dielectric layer 32 and the morphology of the first plating layer are of the same type or substantially the same type. The thickness of the dielectric layer 32 is determined by the effect required for the final interference optically variable coating, and is generally greater than 100 nm and less than 600 nm.

The second plating layer 33 functions as an absorbing layer in the interference optically variable plating layer. The absorbing layer is generally a thin metal material, which is translucent in light transmission. The second plating layer 33 can be made of any one of aluminum, silver, copper, tin, chromium, nickel, and titanium, or an alloy of at least two metals. Since aluminum is low in cost and easy to be removed by acid or alkali, it is preferred For aluminum. The second plating layer 33 is generally formed by a vapor deposition method. After vapor deposition, the surface morphology of the second plating layer 33 is the same or substantially the same as the morphologies of the first plating layer 31 and the dielectric layer 32. The thickness of the second plating layer 33 is generally greater than 2 nm and less than 10 nm.

S3, forming a protective layer 4 material layer on the functional plating layer group 3, as shown in FIG. 5.

The protective layer 4 is generally formed by a printing process. Since the specific volume of the first microstructure on the undulating structure layer 2 is smaller than the specific volume of the second microstructure, the functional plating layer group 3 is generally formed on the undulating structure layer 2 in the same type of covering. Therefore, the function of the first region A The specific volume of the microstructure on the surface of the coating group is still smaller than the specific volume of the microstructure on the surface of the functional coating group in the second region B. The amount of printing of the protective layer 4 can be selected so that the minimum thickness of the surface microstructure of the functional coating group of the protective layer 4 in the first area A is significantly greater than the minimum thickness of the surface microstructure of the functional coating group in the second area B . The minimum thickness of the protective layer 4 in the microstructure is generally located at the top of the microstructure. In this way, the protective effect of the protective layer 4 on the functional coating group in the first area A is significantly higher than the protective effect on the functional coating group in the second area B. Generally, it is required that the coating amount of the protective layer 4 per unit area is greater than 0.1 g/m ² and less than 1 g/m ² . The lower the viscosity of the protective layer 4 before coating, the better it is for leveling. Therefore, the viscosity of the protective glue is generally less than 100 cP, preferably less than 50 cP. As for the components of the protective layer 4, any one of polyester, polyurethane, and acrylic resin or any combination of at least two of them may be varnish or ink as the main resin.

S4. Place the multilayer structure obtained in S3 in an atmosphere capable of reacting with the material of the second plating layer 33 until part or all of the second plating material layer located in the second region B is removed, as shown in FIG. 6 .

As mentioned above, the protective effect of the protective layer 4 on the functional coating group in the first area A is significantly higher than that of the functional coating group in the second area B. Therefore, within a certain period of time, the corrosive atmosphere will reach and corrode the second plating layer 33 through the weak points of the protective layer in the second area B; and during this time, the protective layer 4 is effective for the formation of the second plating layer in the first area A. protection of. Generally, the dielectric layer 32 does not interact with the corrosive atmosphere, that is, the dielectric layer 32 can form an effective protection for the first plating layer 31. In this way, the functional plating layer group 3 accurately located in the first area A and the first plating layer 31 accurately located in the second area B are obtained. If the second plating layer 33 is aluminum or a plating layer containing aluminum, the corrosive atmosphere may be acid or alkali. Generally, after the second plating material layer on the second area B is corroded, the protective layer on the plating layer also floats. Sometimes, after the second plating material layer on the second region B is corroded, part or all of the protective layer on the plating layer may remain on the multilayer body, which does not affect the implementation of subsequent processes.

So far, a semi-finished optical anti-counterfeiting element having the optical characteristics of the functional coating group 3 in the first area A and the optical characteristics of the first coating 31 in the second area B is obtained.

The method of manufacturing the optical anti-counterfeiting element shown in Fig. 2 generally also includes, after step S4, coating other functional coatings 5, such as anti-aging glue, to protect the optical coating, and/or hot melt glue, To play the role of bonding with other substrates.

Example two

As shown in Fig. 7, the optical anti-counterfeiting element contains a first area A, a second area B and a third area C. The first area A has the optical characteristics of the first optical microstructure and the functional coating group, and the second area B has the second area. The optical characteristics of the optical microstructure and the first plating layer are combined, and the third area C has a hollow feature when viewed through perspective. The three areas are strictly positioned with each other. For example, the hollow area C shown in FIG. 7 is strictly located at the boundary of the second area B. Images or hollowed out lines are often very fine, for example, less than 50um. Typically, the functional coating group is a multilayer interference optically variable coating, and the first coating is a metal reflective coating (such as an aluminum layer). In this way, the first area A exhibits interference optically variable characteristics, and the second area B exhibits ordinary metal reflective coating characteristics.

As shown in FIG. 8, the optical anti-counterfeiting element includes a substrate 1, an undulating structure layer 2, a first plating layer 31, a dielectric layer 32, a second plating layer 33, a protective layer 4, and other functional coatings 5. The first plating layer 31, the dielectric layer 32, and the second plating layer 33 constitute the functional plating layer group 3. The substrate 1 and the relief structure layer 2 are usually made of transparent materials. The undulating structure layer 2 includes a first area A composed of a first microstructure, a second area B composed of a second microstructure, and a third area C composed of a third microstructure. The second microstructure The specific volume of is greater than the specific volume of the first microstructure, the specific volume of the third microstructure is greater than the specific volume of the first microstructure, and the aspect ratio of the third microstructure is greater than the aspect ratio of the second microstructure. The first area A is provided with a functional plating layer group 3 composed of a first plating layer 31, a dielectric layer 32, and a second plating layer 33, the second area B is provided with a first plating layer 31 and a dielectric layer 32, and the third area C The first plating layer 31 and the second plating layer 33 are not provided thereon. Generally, the dielectric layer 32 is a colorless and transparent material, and does not provide a special optical effect in the second region B. Viewed from above or/and below the optical anti-counterfeiting element, the first area A presents the optical characteristics combined with the first microstructure and the functional coating group 3, and the second area B presents the optical characteristics combined with the second microstructure and the first coating 31 . Since the first plating layer 31 and the second plating layer 33 are not provided, when the optical anti-counterfeiting element is viewed through transmission, the first region C has a hollow feature. The protective layer 4 is adjacent to the functional plating layer group 3. The protective layer 4 is a natural product in the manufacturing process and generally does not provide additional optical effects. In particular, in the first area A, the first plating layer 31, the dielectric layer 32, and the second plating layer 33 respectively serve as the reflective layer, the dielectric layer, and the absorbing layer to form a group of multilayer interference optically variable plating layers, that is, the first area A It has the anti-counterfeiting feature combining the first microstructure and the multi-layer interference optical variable coating; and the second area B has the anti-counterfeiting feature combining the second microstructure and the ordinary reflective layer. Other functional coatings 5 can be set as required, for example, a bonding layer for bonding with the main product to be protected.

The method for preparing the optical anti-counterfeiting element shown in FIG. 7 according to the present invention will be described below in conjunction with FIG. 9 to FIG. 12. The method includes steps S1' to S4'. For the sake of brevity of description, the functional coating group 3 is selected as a multi-layer interference optical variable coating, and the first coating 31, the dielectric layer 32, and the second coating 33 serve as the reflective layer, the dielectric layer, and the absorbing layer, respectively.

S1', forming an undulating structure layer 2 on the first side surface of the substrate 1, the undulating structure layer 2 including a first area A composed of a first microstructure, a second area B composed of a second microstructure, and The third region C is composed of the third microstructure, the specific volume of the second microstructure is greater than the specific volume of the first microstructure, the specific volume of the third microstructure is greater than the specific volume of the first microstructure, and the specific volume of the third microstructure is greater than that of the first microstructure. The aspect ratio of the structure is greater than the aspect ratio of the second microstructure, as shown in FIG. 9.

In order to achieve the subsequent removal of the plating layer, the specific volume of the second microstructure is greater than the specific volume of the first microstructure, the specific volume of the third microstructure is greater than the specific volume of the first microstructure, and the depth and width of the third microstructure The ratio is greater than the aspect ratio of the second microstructure. Preferably, the specific volume of the first microstructure is greater than or equal to 0 and less than 0.5um ³ /um ² , the specific volume of the second microstructure is greater than 0.4um ³ /um ² and less than 3um ³ /um ² , and the third microstructure The specific volume of ^{the second microstructure is greater than 0.4um 3} /um ² and less than 3um ³ /um ² ; the aspect ratio of the second microstructure is greater than 0 and less than 0.3, and the aspect ratio of the third microstructure is greater than 0.2 and less than 1. The aspect ratio of the first microstructure is not limited, and can be set according to the required optical effect.

The first microstructure, the second microstructure, or the third microstructure is a periodic structure or a structure or a combination of periodic structures; the first microstructure and the second microstructure Or the cross-sectional structure of the third microstructure is any one of a sinusoidal structure, a rectangular grating structure, a trapezoidal grating structure, a blazed grating structure, and a curved grating structure, or a combined structure composed of at least any two structures. The size and lateral arrangement of the first and second microstructures are determined by the required optical effects. The first microstructure can be selected as a flat structure. The function of the third microstructure is only to hollow out, and generally does not provide additional optical effects, so it can be simplified, such as a one-dimensional arrangement, a cross-section of an isosceles triangle with a base width of 10um and a height of 5um (that is, the aspect ratio is 0.5. Blazed grating with a specific volume of 2.5um ³ /um ^{2 ).}

S2', forming a functional plating layer group 3 consisting of a first plating layer 31 material layer, a dielectric layer 32 material layer, and a second plating layer 33 material layer on the undulating structure layer 2, as shown in FIG. 10.

The function of the first plating layer 31 is to serve as a reflective layer in the interference optically variable plating layer. The material of the first plating layer 31 can be any one of Al, Cu, Ni, Cr, Ag, Fe, Sn, Au, and Pt, a mixture or alloy of at least two metals, because aluminum has a lower cost and is easily exposed to acid. Or lye is removed, so aluminum is preferred. The thickness of the first plating layer 31 is generally selected to be greater than 10 nm and less than 80 nm, preferably greater than 20 nm and less than 50 nm. If the metal reflective coating is too thin, the brightness will be insufficient; if the metal reflective coating is too thick, the fastness to the undulating structure layer will be poor, and the cost will increase. The first plating layer 31 can generally be formed on the undulating structure layer 2 by physical and/or chemical vapor deposition methods, such as but not limited to thermal evaporation, magnetron sputtering, MOCVD and the like. Preferably, the first plating layer 31 is formed on the undulating structure layer 2 with a uniform surface density and in a conformal covering manner.

The second plating layer 33 functions as an absorbing layer in the interference optically variable plating layer. The absorbing layer is generally a thin metal material, which is translucent in light transmission. The second plating layer 33 can be made of any one of aluminum, silver, copper, tin, chromium, nickel, and titanium, or an alloy of at least two metals. Since aluminum is low in cost and easy to be removed by acid or alkali, it is preferred For aluminum. The second plating layer 33 is generally formed by a vapor deposition method. After vapor deposition, the surface morphology of the second plating layer 33 is the same type or substantially the same type as the morphology of the first plating layer 31 and the dielectric layer 32. The thickness of the second plating layer 33 is generally greater than 2 nm and less than 10 nm.

S3', forming a protective layer 4 material layer on the functional plating layer group 3, as shown in FIG. 11.

The protective layer 4 is generally formed by a printing process. Since the specific volume of the first microstructure on the undulating structure layer 2 is smaller than the specific volume of the second and third microstructures, the functional plating layer group 3 is generally formed on the undulating structure layer 2 in the same type of covering. The specific volume of the microstructure on the surface of the functional coating group in a region A is still smaller than the specific volume of the microstructure on the surface of the functional coating group in the second region B and the third region C. The amount of printing of the protective layer 4 can be selected so that the minimum thickness of the surface microstructure of the protective layer 4 in the first area A of the functional coating group is significantly larger than the surface of the functional coating group in the second area B and the third area C The minimum thickness of the microstructure. The minimum thickness of the protective layer 4 in the microstructure is generally located at the top of the microstructure. In this way, the protective effect of the protective layer 4 on the functional coating group in the first area A is significantly higher than the protective effect on the functional coating group in the second area B and the third area C. It is generally required that the printing volume per unit area of the protective layer 4 is greater than 0.1 g/m ² and less than 1 g/m ² . The lower the viscosity of the protective layer 4 before coating, the better it is for leveling. Therefore, the viscosity of the protective glue is generally less than 100 cP, preferably less than 50 cP. As for the components of the protective layer, any one of polyester, polyurethane, and acrylic resin or any combination of at least two of them may be varnish or ink as the main resin.

S4', placing the multilayer structure obtained in S3' in an atmosphere capable of reacting with the materials of the first plating layer 31 and the second plating layer 33 until the second plating layer material layer located in the second area B and the third area C Part or all of the first plating material layer and the second plating material layer are removed, as shown in FIG. 12.

As mentioned above, the protective effect of the protective layer 4 on the functional coating group in the first area A is significantly higher than the protective effect on the functional coating group in the second area B and the third area C. Therefore, within a certain period of time, the corrosive atmosphere will reach and corrode the second plating layer 33 through the weak points of the protective layers of the second area B and the third area C. Since the aspect ratio of the third microstructure is greater than that of the second microstructure, the dielectric layer of the third region will form more cracks than the dielectric layer of the second region B, so the dielectric layer of the third region C The protective effect of the layer on the first plating material layer below it is worse than that of the dielectric layer of the second region B on the protection effect of the first plating material layer below it. Therefore, in the third area C, after the corrosive atmosphere has etched the second plating layer in the third area, the first plating layer 31 will continue to be corroded through the weak spots of the dielectric layer; in the second area B, the first plating layer 31 is mediated The effective protection of the electrical layer is retained. In this way, the functional coating group accurately located in the first area A, and the first coating layer 31 accurately located in the second area B; the second coating material layer located in the second area B, and the functional coating group located in the third area C are obtained. It is precisely removed. If the first plating layer 31 and the second plating layer 33 are aluminum or a plating layer containing aluminum, the corrosive atmosphere may be an acid solution or an alkaline solution. Generally, after the second plating material layer on the second area B and the third area C is corroded, the protective layer on the plating layer also floats. Sometimes, after the second plating material layer on the second area B and the third area C is corroded, part or all of the protective layer on the plating layer may remain on the multilayer body, which does not affect the implementation of subsequent processes.

So far, a semi-finished optical anti-counterfeiting element with the optical features presented by the functional coating group 3 in the first area A, the optical features presented by the first coating 31 in the second area B, and the hollow feature in the third area C is obtained.

The method of manufacturing the optical anti-counterfeiting element shown in FIG. 7 generally also includes, after the step S4', coating other functional coatings 5, such as anti-aging glue, to protect the optical coating, and/or hot melt glue , In order to play a role in bonding with other substrates.

The method for preparing an optical anti-counterfeiting element according to the present invention is suitable for manufacturing window security threads, labels, logos, wide strips, transparent windows, coatings and the like. The anti-counterfeiting paper with the window security thread is used for anti-counterfeiting of various high-security products such as banknotes, passports, and securities.

The above describes the optional implementation manners of the embodiments of the present invention in detail with reference to the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the foregoing embodiments. Within the scope of the technical concept of the embodiments of the present invention, the embodiments of the present invention can be compared. The technical solution of the present invention undergoes a variety of simple modifications, and these simple modifications all fall within the protection scope of the embodiments of the present invention.

In addition, it should be noted that the various specific technical features described in the foregoing specific embodiments can be combined in any suitable manner, provided that there is no contradiction. In order to avoid unnecessary repetition, various possible combinations are not further described in the embodiment of the present invention.

Those skilled in the art can understand that all or part of the steps in the method of the above-mentioned embodiments can be implemented by instructing relevant hardware through a program. The program is stored in a storage medium and includes several instructions to enable the single-chip microcomputer, chip, or processor. (processor) Execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage media include: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), magnetic disks or optical disks and other media that can store program codes. .

In addition, various different implementation manners of the embodiments of the present invention can also be combined arbitrarily, as long as they do not violate the idea of the embodiments of the present invention, they should also be regarded as the content disclosed in the embodiments of the present invention.

Claims

An optical anti-counterfeiting element, characterized in that the optical anti-counterfeiting element comprises:

Undulating structure layer (2);

The undulating structure layer (2) includes a first region (A) with a first microstructure and a second region (B) with a second microstructure, and the specific volume of the second microstructure is larger than that of the first microstructure. The specific volume of the structure;

One side of the undulating structure layer (2) has a first plating layer (31), a dielectric layer (32), a second plating layer (33) and a protective layer (4) stacked in sequence;

The first plating layer (31) and the dielectric layer (32) are located in the first area (A) and located in the second area (B), the second plating layer (33) and the protective layer (4) Located in the first area (A) but not in the second area (B);

Wherein, the first plating layer (31), the dielectric layer (32), and the second plating layer (33) constitute a functional plating layer group (3), and the functional plating layer group (3) and the first micro The structure has a combined optical feature in the first area (A), and the first plating layer (31) and the second microstructure have a combined optical feature in the second area (B).
The optical anti-counterfeiting element according to claim 1, wherein:

The first microstructure or the second microstructure is a periodic structure or a structure or a combination structure in a periodic structure;

The cross-sectional structure of the first microstructure or the second microstructure is any one of a sinusoidal structure, a rectangular grating structure, a trapezoidal grating structure, a blazed grating structure, and an arc grating structure, or at least any two structures. The combined structure.
The optical anti-counterfeiting element according to claim 1, wherein:

The specific volume of the first microstructure is greater than or equal to 0um 3 /um 2 and less than 0.5um 3 /um 2 ;

The specific volume of the second microstructure is greater than 0.4um 3 /um 2 and less than 3um 3 /um 2 .
The optical anti-counterfeiting element according to claim 1, wherein:

The first plating layer (31) is adjacent to the undulating structure layer (2).
The optical anti-counterfeiting element according to claim 1, wherein:

The material of the first plating layer (31) or the second plating layer (33) is any one of nickel, chromium, aluminum, silver, copper, tin, and titanium, or an alloy composed of a combination of at least any two metals;

The material of the dielectric layer (32) is magnesium fluoride, silicon dioxide, zinc sulfide, titanium nitride, titanium dioxide, titanium monoxide, titanium trioxide, titanium pentoxide, tantalum pentoxide, and two Any one compound of niobium, ceria, bismuth trioxide, chromium oxide green, iron oxide, hafnium oxide and zinc oxide or a mixture of at least any two compounds.
The optical anti-counterfeiting element according to claim 1, wherein:

The functional coating group (3) is a multi-layer interference optically variable coating, and the optical anti-counterfeiting element on any side of the multi-layer interference optically variable coating has the characteristic of interference optically variable.
The optical anti-counterfeiting element according to claim 1, wherein:

The undulating structure layer (2) also includes a third region (C) having a third microstructure, the aspect ratio of the third microstructure is greater than the aspect ratio of the second microstructure, and the third The specific volume of the microstructure is greater than the specific volume of the first microstructure;

The first plating layer (31) and the second plating layer (33) are not located in the third area (C);

The optical anti-counterfeiting element has a hollow feature in the third area (C).
The optical anti-counterfeiting element according to claim 7, wherein:

The aspect ratio of the third microstructure is greater than 0.2 and less than 1;

The aspect ratio of the second microstructure is greater than 0 and less than 0.3;

The specific volume of the third microstructure is greater than 0.4um 3 /um 2 and less than 3um 3 /um 2 .
A manufacturing method of an optical anti-counterfeiting element, characterized in that the manufacturing method includes:

S1) forming an undulating structure layer, wherein the undulating structure layer includes a first region having a first microstructure and a second region having a second microstructure, and the specific volume of the second microstructure is larger than that of the first microstructure. The specific volume of the structure;

S2) sequentially forming a laminated first plating material layer, a dielectric layer material layer, a second plating material layer, and a protective layer material layer on one side of the undulating structure layer;

S3) The semi-finished product of step S2) is placed in an atmosphere capable of reacting with the second plating material layer until part or all of the second plating material layer in the second area is removed, and only in the At least a laminated first plating layer and a second plating layer are left in the first area, wherein the first plating layer and the second plating layer are the first plating layer material layer and the second plating layer material layer located in the Part of the plating material layer in the first area that has not been removed.
The method of manufacturing an optical anti-counterfeiting element according to claim 9, characterized in that:

The undulating structure layer in step S1) further includes a third region having a third microstructure, the aspect ratio of the third microstructure is greater than the aspect ratio of the second microstructure, and the ratio of the third microstructure is The volume is greater than the specific volume of the first microstructure.
The manufacturing method of an optical anti-counterfeiting element according to claim 10, wherein the manufacturing method further comprises:

S4) Place the semi-finished product of step S3) in an atmosphere capable of reacting with the first plating material layer until the first plating material layer and the second plating material layer in the third area are partially or completely removed.
The method of manufacturing an optical anti-counterfeiting element according to claim 11, wherein:

The first plating layer or/and the second plating layer in step S3) contains an aluminum layer;

The atmosphere capable of reacting with the first coating material layer or/and the second coating material layer in step S3) selects an acid solution and/or an alkali solution.
The method for manufacturing an optical anti-counterfeiting element according to any one of claims 9 to 12, wherein the manufacturing method further comprises:

Apply inorganic or organic plating or coating process.