Optical anti-counterfeiting element and manufacturing method thereof

Abstract

The invention provides an optical anti-fake element and a manufacturing method thereof, and belongs to the technical field of optical anti-fake, and the method comprises the steps that a fluctuating structure layer is formed on the surface of a base material, the fluctuating structure layer is provided with a first area and a second area, the second area is provided with at least two non-adjacent sub-areas, one sub-area is the first sub-area, and the other sub-area is the second sub-area; a first reflecting layer is formed on the fluctuating structure layer; forming a protective layer on the first reflecting layer, and placing the optical anti-counterfeiting element in an atmosphere capable of reacting with the first reflecting layer until the first reflecting layer in the second region is completely corroded but the first reflecting layer in the first region is reserved; a first ink layer is formed on the area at least comprising the first sub-area, and a second ink layer is formed on the area at least comprising the second sub-area; a second reflective layer is formed on the first ink layer and the second ink layer. Strict alignment of the first reflecting layer and the second reflecting layer with the microstructure is realized, and the anti-counterfeiting performance which is easy to identify and difficult to counterfeit is very strong.

Description

Technical Field

[0001] The present invention relates to the technical field of optical anti-counterfeiting, and particularly relates to an optical anti-counterfeiting element and a manufacturing method thereof. Background Art

[0002] In order to prevent forgery by means such as scanning and photocopying, optical anti-counterfeiting technologies have been widely adopted in various high-security or high-value-added printed matter such as banknotes, credit cards, passports, securities, and product packaging, and very good results have been achieved.

[0003] Among various optical anti-counterfeiting technologies, the optical effects formed by microstructures, including diffraction, non-diffraction, etc., have been widely applied due to their high brightness and obvious dynamic effects. Among them, the holographic technology, which is the most widely used optical anti-counterfeiting technology in optical thin films at present, is an optical technology developed by utilizing the diffraction effect formed by microstructures. In order to increase the brightness of the image, the microstructural optical anti-counterfeiting technology generally uses a metal reflective layer.

[0004] The color presented by the optical microstructure based on a single metal reflective layer is relatively monotonous. For example, the silver effect presented by aluminum. Patent application CN103702841B discloses that a colored ink coating is applied to some regions between the optical microstructure and the metal reflective layer, which can improve the appearance of the single metal reflective layer and endow the optical microstructure with a full-color effect. This process can achieve the integration of multiple inks and further enrich the color effect of the anti-counterfeiting element.

[0005] However, based on this method, the position of the colored ink coating is determined by the accuracy of the printing process, generally greater than 100um. Therefore, the position of the ink coating and the position of the microstructure cannot be strictly aligned, which limits the application of the product in the high-end anti-counterfeiting field. Summary of the Invention

[0006] Therefore, the technical problem to be solved by the present invention is to overcome the defect that in the prior art, when a colored ink coating is added to a single metal reflective layer, the position of the ink coating and the position of the microstructure cannot be strictly aligned, so as to provide an optical anti-counterfeiting element and a manufacturing method thereof.

[0007] To solve the above technical problem, the present invention provides a manufacturing method of an optical anti-counterfeiting element, including the following steps:

[0008] Form a relief structure layer on the surface of a substrate. The relief structure layer has a first region and a second region. The first region has a first microstructure, and the second region has a second microstructure. The specific volume of the first microstructure is smaller than the specific volume of the second microstructure. The second region has at least two non-adjacent sub-regions, one of which is a first sub-region and the other is a second sub-region;

[0009] Form a first reflective layer on the undulating structure layer;

[0010] Form a protective layer on the first reflective layer, where the minimum thickness of the protective layer in the first region is greater than the minimum thickness of the protective layer in the second region;

[0011] Place the optical anti-counterfeiting element in an atmosphere that can react with the first reflective layer until the first reflective layer in the second region is completely corroded but the first reflective layer in the first region remains;

[0012] Form a first ink layer on the region including at least the first sub-region, and form a second ink layer on the region including at least the second sub-region;

[0013] Form a second reflective layer on the first ink layer and the second ink layer.

[0014] Optionally, the specific volume of the first microstructure ranges from greater than or equal to 0 um 3 / um 2 and less than 1 um 3 / um 2 ; the specific volume of the second microstructure ranges from greater than 0.4 um 3 / um 2 and less than 2 um 3 / um 2 .

[0015] Optionally, after the first ink layer and the second ink layer are formed, the surface away from the undulating structure layer has the same or similar undulating shape as the surface of the undulating structure layer at the corresponding position.

[0016] Optionally, the first region and / or the second region are presented in the form of a line or dot pattern, and the width of the line or the diameter of the dot is less than 0.25 mm.

[0017] Optionally, the amount of the first ink layer and the second ink layer applied is greater than 0.1 g / m 2 , less than 1 g / m 2 .

[0018] Optionally, the first ink layer and the second ink layer are formed by a wet coating process.

[0019] Optionally, the first ink layer and the second ink layer are semi-transparent layers.

[0020] Optionally, the distance between the first sub-region and the second sub-region is greater than 100 microns.

[0021] Optionally, the first reflective layer is a multi-layer interference optical variable coating;

[0022] When observed vertically, the multi-layer interference optical variable coating exhibits the same or similar color characteristics as the first ink layer, and when observed obliquely, it exhibits the same or similar color characteristics as another one of the second ink layers.

[0023] Optionally, the thickness of the first reflective layer is greater than 10 nm and less than 80 nm.

[0024] Optionally, the following steps are further included:

[0025] After forming the second reflective layer, continue to perform the process of applying other inorganic or organic coatings or layers to achieve other optical anti-counterfeiting functions or auxiliary functions.

[0026] The present invention also provides an optical anti-counterfeiting element, including:

[0027] An undulating structure layer having a first region and a second region, the first region having a first microstructure, the second region having a second microstructure, and the specific volume of the first microstructure being less than the specific volume of the second microstructure; the second region has at least two non-adjacent sub-regions, one of which is a first sub-region and the other is a second sub-region;

[0028] A first reflective layer located only on the undulating structure layer in the first region;

[0029] A protective layer located on the first reflective layer;

[0030] A first ink layer located on at least the first sub-region;

[0031] A second ink layer located on at least the second sub-region;

[0032] A second reflective layer located on the first ink layer and the second ink layer.

[0033] The technical solution of the present invention has the following advantages:

[0034] By providing the first reflective layer and the second reflective layer with different color characteristics, a colorful optical anti-counterfeiting element is obtained. By the specific volume of the first microstructure being less than the specific volume of the second microstructure, strict alignment of the first reflective layer and the second reflective layer with the microstructure is achieved, and it has strong anti-counterfeiting performance that is easy to identify and difficult to forge.

[0035] Other features and advantages of the present invention will be described in detail in the subsequent specific implementation section. Description of the Drawings

[0036] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0037] Figure 1 Top view of the optical anti-counterfeiting element according to an embodiment of the present invention;

[0038] Figure 2 For along Figure 1 A possible cross-sectional view seen along the X-X line in

[0039] Figures 3 to 8 Is a process cross-sectional view of the manufacturing method of the optical anti-counterfeiting element of the present invention.

[0040] Explanation of reference numerals:

[0041] 1, substrate; 2, undulating structure layer; 3, first reflective layer; 4, protective layer; 501, first ink layer; 502, second ink layer; 6, second reflective layer; 7, coating; A, first region; B, second region; B1, first sub-region; B2, second sub-region. Specific embodiments

[0042] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the drawings. Obviously, the described embodiments are some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0043] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0044] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0045] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0046] Figure 1 is a top view of the optical anti-counterfeiting element according to an embodiment of the present invention. The first region A of the optical anti-counterfeiting element contains the effect of presenting the combination of the first microstructure and the first reflective layer 3. For example, the first microstructure is a microstructure that can present a dynamic effect, and the first reflective layer 3 is a multi-layer interference color-changing coating (for example, gold when observed vertically and green when observed obliquely). That is, the combination of the two can present a dynamic color-changing effect similar to that of the 50-yuan RMB note in 2019 version; the second region B presents the effect of the combination of the second microstructure and the ink layer. For example, the first sub-region B1 (the four-corner star region) of the second region B presents a relief effect with a first color (for example, gold), and the second sub-region B2 (the five-pointed star region) of the second region B presents a relief effect with a second color (for example, green). It should be emphasized that the first color region and the four-corner star with a relief structure are strictly aligned without error. Similarly, the second color region and the five-pointed star with a relief structure are strictly aligned without error. In particular, the tips of the quadrilateral and the five-pointed star can be very fine. For example, the line width is less than 50 um. This is difficult to achieve with existing ordinary printing processes. When the product is observed vertically, the gold four-corner stars blend in with the background, while the five-pointed star has a prominent and eye-catching green color. When observed obliquely, the green five-pointed star blends in with the background, while the four-corner stars have a prominent and eye-catching gold color.

[0047] Figure 2 is a possible cross-sectional view seen along the Figure 1 X-X line in. The optical anti-counterfeiting element includes a substrate 1, a relief structure layer 2, a first reflective layer 3, a protective layer 4, a first ink layer 501, a second ink layer 502, a second reflective layer 6, and other functional coatings 7. According to the optical characteristics of the microstructure, the relief structure layer 2 is divided into a first region A and a second region B. When the observer observes from one side of the substrate 1, the optical effect of the first reflective layer 3 strictly located in the first region A can be seen; and the optical effect of the first ink layer 501 strictly located in the first sub-region B1 of the second region B, and the optical effect of the second ink layer 502 strictly located in the second sub-region B2 of the second region B.

[0048] This embodiment provides a method for manufacturing an optical anti-counterfeiting element, comprising the following steps:

[0049] As Figure 3 shown, a relief structure layer 2 is formed on the surface of a substrate 1. The relief structure layer 2 has a first region A and a second region B. The first region A has a first microstructure, and the second region B has a second microstructure. The specific volume of the first microstructure is smaller than that of the second microstructure. The second region B has at least two non-adjacent sub-regions, one of which is a first sub-region B1 and the other is a second sub-region B2;

[0050] As Figure 4 shown, a first reflective layer 3 is formed on the relief structure layer 2;

[0051] As Figure 5 shown, a protective layer 4 is formed on the first reflective layer 3. The minimum thickness of the protective layer 4 in the first region A is greater than the minimum thickness of the protective layer 4 in the second region B;

[0052] As Figure 6 shown, the optical anti-counterfeiting element is placed in an atmosphere that can react with the first reflective layer 3 until the first reflective layer 3 in the second region B is completely corroded but the first reflective layer 3 in the first region A remains;

[0053] As Figure 7 shown, a first ink layer 501 is formed on the region at least including the first sub-region B1, and a second ink layer 502 is formed on the region at least including the second sub-region B2;

[0054] As Figure 8 shown, a second reflective layer 6 is formed on the first ink layer 501 and the second ink layer 502.

[0055] Specifically, the substrate 1 can be at least partially transparent, or a colored dielectric layer, or a transparent dielectric film with a functional coating on its surface, or a multilayer film formed by lamination. The substrate 1 is generally formed of a thin film material with good physical and chemical resistance and high mechanical strength. For example, plastic films such as polyethylene terephthalate (PET) film, polyethylene naphthalate (PEN) film, and polypropylene (PP) film can be used to form the substrate 1, and the substrate 1 is preferably formed of PET material. The substrate 1 may contain an adhesion enhancement layer to enhance the adhesion between the substrate 1 and the relief structure layer 2, or may contain a release layer to facilitate the separation of the substrate 1 from the relief structure layer 2.

[0056] 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, when the thermoplastic resin pre-printed on the substrate 1 passes through a high-temperature metal template, it is heated and softened and deformed to form a specific undulating structure, and then cooled and formed. The undulating structure layer 2 can also be formed by a radiation curing casting process, that is, by printing a radiation curing resin on the substrate 1, while pressing the original plate on it and irradiating radiation such as ultraviolet rays or electron beams to cure the above materials, and then removing the original plate to form the undulating structure layer 2.

[0057] When using the optical anti-counterfeiting element of the present invention, when observed from the non-processing side (i.e., one side of the substrate 1), the first region A has the visual characteristics presented by the first reflective layer 3, the first sub-region B1 of the second region B has the visual characteristics of the combination of the second reflective layer 6 and the first ink layer 501, and the second sub-region B2 of the second region B has the visual characteristics of the combination of the second reflective layer 6 and the second ink layer 502; it should be emphasized that the optical characteristics presented by the first microstructure and the first reflective layer 3 are strictly aligned, and the optical characteristics presented by the second microstructure and the second reflective layer 6 are strictly aligned with zero error. Therefore, it has strong anti-counterfeiting characteristics that are easy to identify and difficult to forge. At the same time, since the microstructure and the reflective layer are accurately positioned, theoretically the size of the optical image line can approach zero. The optical characteristics presented by the microstructure include common characteristics well-known in the art, such as rainbow holography, relief, scaling, scrolling, etc.

[0058] The so-called specific volume of the microstructure refers to the ratio of the volume of the liquid that exactly fills the microstructure to its projected area when the optical anti-counterfeiting element is placed horizontally, and its unit is um 3 / um 2 . The purpose of setting the difference in the specific volume of the first microstructure and the second microstructure is to achieve the removal of the material of the first reflective layer 3 in the second region B.

[0059] The first microstructure or the second microstructure can be a periodic structure, an aperiodic structure, or a combination of a periodic structure and an aperiodic structure according to the optical characteristics to be presented; their cross-sectional structures along the extension direction can be a sinusoidal structure, a rectangular grating structure, a trapezoidal grating structure, a blazed grating structure, an arc grating structure, or a combination of at least any two structures. In particular, the first microstructure can be selected from a flat structure. We define a flat structure as an undulating structure with a specific volume of zero. In this embodiment, the first microstructure is an optical microstructure with a dynamic effect, its cross-section is a blazed grating structure, the width is not fixed, it is 5-15um, and the specific volume is about 0.5um 3 / um 2; If the second microstructure is an optical microstructure with a relief effect, its cross-section can be a Fresnel grating structure, and the specific volume is about 1um 3 / um 2 .

[0060] The first reflective layer 3 can be a multi-layer interference optical variable coating, that is, it presents different colors when observed from different angles. In this way, a more advanced anti-counterfeiting effect can be formed in the first region A than that of a common single-metal coating (such as an aluminum layer). Typically, the multi-layer interference optical variable coating includes a mirror layer, a dielectric layer, and an absorption layer (observed from the side of the absorption layer). The absorption layer is adjacent to the undulating structure layer. The mirror layer is selected from aluminum, silver, copper, tin, chromium, nickel, titanium, or their alloys. Based on considerations of price and brightness, aluminum is preferably used. The dielectric layer is selected from MgF2, SiO2, ZnS, TiN, TiO2, TiO, Ti2O3, Ti3O5, Ta2O5, Nb2O5, CeO2, Bi2O3, Cr2O3, Fe2O3, HfO2, or ZnO. The absorption layer is selected from nickel, chromium, aluminum, silver, copper, tin, titanium, or their alloys. Since aluminum is easy to react with acids and alkalis and is removed in the second region, aluminum or aluminum alloy is preferably used.

[0061] Specific method for forming the first reflective layer 3: The material of the first reflective layer 3 is formed by vapor deposition on the undulating structure layer 2. The method of vapor deposition can specifically include but is not limited to thermal evaporation, electron beam evaporation, magnetron sputtering, etc. Preferably, the material of the first reflective layer 3 is formed on the undulating structure layer 2 in a uniform surface density and in a homomorphic covering or substantially homomorphic covering manner. In this embodiment, the material of the first reflective layer 3 is a multi-layer interference color-changing coating that is golden when observed straight on and green when observed obliquely. The structure is a sandwich structure of Al (absorption layer) / TiO2 (dielectric layer) / Al (mirror layer), with thicknesses of 5, 370, and 40nm respectively, and the absorption layer is adjacent to the undulating structure layer.

[0062] Specific method for forming the protective layer 4: The process for forming the material of the protective layer 4 generally adopts a wet coating process. In terms of the forming area, it can be formed in the entire area of the film (referred to as the coating process), or it can be formed in a partial area of the film (referred to as the printing process). In terms of specific implementation techniques, there can be spraying, roll coating, spin coating, flexography, gravure printing, screen printing, etc. The amount of the material of the protective layer 4 applied is generally greater than 0.1g / m 2 , less than 1g / m 2 . In this way, in the subsequent hollowing process, in a corrosive atmosphere that can react with the material of the first reflective layer 3, the protective layer 4 can provide effective protection for the material of the first reflective layer 3 in the image area A, but cannot provide effective protection for the material of the first reflective layer 3 in the second region B. The main resin of the protective layer 4 can be composed of polyurethane, acrylic acid, polyester, or their combination. Among them, the protective layer 4 has a dry coating weight of 0.6g / m 2The main body is a coating material of polyurethane resin.

[0063] As described above, the minimum thickness of the material of the first reflective layer 3 in the first region A of the protective layer 4 material is significantly greater than the minimum thickness of the material of the first reflective layer 3 in the second region B. In this way, in a corrosive atmosphere that can react with the material of the first reflective layer 3, the corrosive atmosphere reaches the underlying first reflective layer 3 material through the vulnerable points (i.e., corresponding to the top of the microstructure) of the protective layer 4 material in the second region B, and corrodes it. At the same time, the protective layer 4 material located in the first region A can effectively protect the underlying first reflective layer 3 material, so that the first reflective layer 3 accurately located in the first region A is obtained. In this embodiment, since the material of the first reflective layer 3 is selected as an Al / TiO2 / Al laminated structure, the corrosive atmosphere can be selected as an alkaline solution or an acid solution, such as a NaOH solution or a sulfuric acid solution. The alkaline solution or acid solution will first corrode the outermost mirror layer of the second region B, and then penetrate through the relatively loose dielectric layer to reach and corrode the innermost absorption layer. After the absorption layer is corroded away, the dielectric layer and the protective layer 4 that do not react with the alkaline solution or acid solution on it are also peeled off.

[0064] The manufacturing method of the optical anti-counterfeiting element provided in this embodiment, the specific volume range of the first microstructure is greater than or equal to 0 um 3 / um 2 and less than 1 um 3 / um 2 ; the specific volume range of the second microstructure is greater than 0.4 um 3 / um 2 and less than 2 um 3 / um 2 , the morphology and specific structural parameters of the first microstructure and the second microstructure are set according to the required optical effects.

[0065] The manufacturing method of the optical anti-counterfeiting element provided in this embodiment, after the first ink layer 501 and the second ink layer 502 are formed, the surface away from the undulating structure layer 2 has the same or similar undulating shape as the surface of the corresponding undulating structure layer 2. The amount of ink layer applied should be controlled as low as possible. At the same time, to maintain the color saturation of the ink, it cannot be too thin. The dry layer amount of the first ink layer 501 and the second ink layer 502 is preferably greater than 0.1 g / m 2 , less than 1 g / m 2 , in this embodiment, the dry layer amount of the first ink layer 501 and the second ink layer 502 is about 0.2 g / m 2 , the first ink layer 501 and the second ink layer 502 are respectively a gold and a green ink layer, so that when observing vertically and obliquely in the final product, a pairing effect with the first reflective layer 3 is presented.

[0066] The manufacturing method of the optical anti-counterfeiting element provided in this embodiment, wherein the first region A and / or the second region B are presented in the form of a pattern of lines or dots, and the width of the lines or the diameter of the dots is less than 0.25 mm, which is suitable for manufacturing products with extremely fine lines.

[0067] The manufacturing method of the optical anti-counterfeiting element provided in this embodiment, wherein the first ink layer 501 and the second ink layer 502 are formed by a wet coating process. The wet coating process is in contrast to vapor deposition. The wet coating process refers to a process of applying a liquid material onto a thin film and then drying or curing it. Generally speaking, since the raw materials used in the wet coating process are liquid materials with fluidity, except for flat structures, the surface undulation shape of the formed thin film layer generally has a relatively obvious change compared with the surface undulation shape of the substrate. The most significant one is the reduction in depth, that is, the undulation shape becomes flatter. If the amount of the wet coating layer is controlled to be small, the surface undulation shape of the wet coating layer can be made basically the same as the surface of the substrate. For the rolled materials in large-scale production, the vapor deposition process can only be set over the full width, and the obvious advantage of the wet coating process compared with the vapor deposition process is that it can be set locally, thus meeting various design requirements. In addition, the color selection space of the raw material ink for the wet coating process is large, and the color and luster are full and rich, while the raw materials used in the vapor deposition process are generally metal materials, and the available colors are less. The wet coating process can be gravure printing, flexographic printing, screen printing, or letterpress printing.

[0068] The manufacturing method of the optical anti-counterfeiting element provided in this embodiment, wherein the first ink layer 501 and the second ink layer 502 are semi-transparent layers to enhance the intensity of the light reflected by the second reflective layer 6.

[0069] The manufacturing method of the optical anti-counterfeiting element provided in this embodiment. For the convenience of the operation of the wet coating process, the first sub-region B1 and the second sub-region B2 of the second region B are not adjacent, and the distance between the first sub-region B1 and the second sub-region B2 is greater than 100 microns. In this way, the first ink layer 501 can be set in a larger region C1 including the first sub-region B1 without affecting the second sub-region B2, and the second ink layer 502 can be set in a larger region C2 including the second sub-region B2 without affecting the first sub-region B1. That is, in the final product, the color of the first ink layer 501 is accurately presented in the first sub-region B1, and the color of the second ink layer 502 is accurately presented in the second sub-region B2.

[0070] The second reflective layer 6 provides a metallic luster for the first ink layer 501 and the second ink layer 502, and reproduces the microstructure optical effect. The second reflective layer 6 only functions as a reflector and can be selected from aluminum, silver, copper, tin, chromium, nickel, titanium or their alloys formed by vapor deposition. Aluminum has a high reflectivity and low cost, so it is preferably aluminum or an aluminum alloy. The second reflective layer 6 can also be selected from metal inks formed by a wet coating process, preferably aluminum ink with a high reflectivity and low cost. To ensure that the pigment flake particles of the metal ink cover the surfaces of the first ink layer 501 and the second ink layer 502 as homogeneously as possible, the average diameter of the pigment flake particles must be smaller than the width of the cross-section of the second microstructure. Generally, it is required that the average diameter of the pigment flake particles of the metal ink is less than 10 μm. The second reflective layer 6 can be applied to the product over the entire surface or locally, but it should cover at least the first sub-region B1 and the second sub-region B2 of the second region B.

[0071] Specifically, one side of the optical anti-counterfeiting element substrate 1 adjacent to the undulating structure layer 2 contains a release layer, so that after the optical anti-counterfeiting element is transferred to the protected product, the substrate or the main body of the substrate is separated from the protected product.

[0072] In the manufacturing method of the optical anti-counterfeiting element provided in this embodiment, the first reflective layer 3 is a multi-layer interference optical variable coating; when observed vertically, the multi-layer interference optical variable coating presents the same or similar color characteristics as the first ink layer 501, and when observed obliquely, it presents the same or similar color characteristics as the other second ink layer 502. In this way, a more advanced anti-counterfeiting effect can be formed in the first region A than that of a common single metal coating (such as an aluminum layer).

[0073] In the manufacturing method of the optical anti-counterfeiting element provided in this embodiment, the thickness of the first reflective layer 3 is greater than 10 nm and less than 80 nm, preferably greater than 20 nm and less than 50 nm. To effectively cover the ineffective second reflective layer 6 (i.e., the second reflective layer 6 in the first region A), the first reflective layer 3 needs to be greater than a certain thickness. At the same time, if the reflective layer is too thick, the adhesion to the undulating structure layer is poor, and the cost increases.

[0074] The manufacturing method of the optical anti-counterfeiting element provided in this embodiment further includes the following steps: after forming the second reflective layer 6, continue with the process of applying other inorganic or organic coatings or layers 7 to achieve other optical anti-counterfeiting functions or auxiliary functions. Specifically, a hot melt adhesive coating can be applied to facilitate bonding with the protected product.

[0075] This embodiment also provides an optical anti-counterfeiting element, which includes a relief structure layer 2, a first reflective layer 3, a protective layer 4, a first ink layer 501, a second ink layer 502, and a second reflective layer 6. The relief structure layer 2 has a first region A and a second region B. The first region A has first microstructures, and the second region B has second microstructures. The specific volume of the first microstructures is smaller than that of the second microstructures. The second region B has at least two non-adjacent sub-regions, one of which is a first sub-region B1 and the other is a second sub-region B2. The first reflective layer 3 is only located on the relief structure layer 2 in the first region A. The protective layer 4 is located on the first reflective layer 3. The first ink layer 501 is located on at least the first sub-region B1. The second ink layer 502 is located on at least the second sub-region B2. The second reflective layer 6 is located on the first ink layer 501 and the second ink layer 502.

[0076] Obviously, the above embodiments are merely examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A method for manufacturing an optical anti-counterfeiting element, characterized in that, Including the following steps: Form a relief structure layer (2) on the surface of a substrate (1), the relief structure layer (2) having a first region (A) and a second region (B), the first region (A) having a first microstructure, the second region (B) having a second microstructure, the specific volume of the first microstructure being less than the specific volume of the second microstructure; the second region (B) having at least two non-adjacent sub-regions, one of which is a first sub-region (B1) and the other is a second sub-region (B2); Form a first reflective layer (3) on the relief structure layer (2); Form a protective layer (4) on the first reflective layer (3), the minimum thickness of the protective layer (4) in the first region (A) being greater than the minimum thickness of the protective layer (4) in the second region (B); Place the optical anti-counterfeiting element in an atmosphere capable of reacting with the first reflective layer (3) until the first reflective layer (3) in the second region (B) is completely corroded but the first reflective layer (3) in the first region (A) remains; Form a first ink layer (501) on the region including at least the first sub-region (B1), and form a second ink layer (502) on the region including at least the second sub-region (B2); Form a second reflective layer (6) on the first ink layer (501) and the second ink layer (502).

2. The manufacturing method of the optical anti-counterfeiting element according to claim 1, characterized in that, The specific volume of the first microstructure ranges from greater than or equal to 0 um 3 / um 2 and less than 1 um 3 / um 2 ; the specific volume of the second microstructure ranges from greater than 0.4 um 3 / um 2 and less than 2 um 3 / um 2 .

3. The manufacturing method of the optical anti-counterfeiting element according to claim 1, characterized in that, After the first ink layer (501) and the second ink layer (502) are formed, the surface away from the relief structure layer (2) has the same or similar relief shape as the surface of the relief structure layer (2) at the corresponding position.

4. The manufacturing method of the optical anti-counterfeiting element according to claim 3, characterized in that, The first region (A) and / or the second region (B) are presented in the form of a line or dot pattern, and the width of the line or the diameter of the dot is less than 0.25 mm.

5. The manufacturing method of the optical anti-counterfeiting element according to claim 1, characterized in that, The applied amounts of the first ink layer (501) and the second ink layer (502) are greater than 0.1 g / m 2 , and less than 1 g / m 2 .

6. The manufacturing method of the optical anti-counterfeiting element according to claim 1, characterized in that, The first ink layer (501) and the second ink layer (502) are formed by a wet coating process.

7. The manufacturing method of the optical anti-counterfeiting element according to claim 1, characterized in that, The first ink layer (501) and the second ink layer (502) are semi-transparent layers.

8. The manufacturing method of the optical anti-counterfeiting element according to claim 1, characterized in that, The distance between the first sub-region (B1) and the second sub-region (B2) is greater than 100 microns.

9. The method for manufacturing an optical anti-counterfeiting element according to claim 1, wherein The first reflective layer (3) is a multi-layer interference optical variable coating; When observed vertically, the multi-layer interference optical variable coating exhibits the same or similar color characteristics as the first ink layer (501), and when observed obliquely, it exhibits the same or similar color characteristics as the other second ink layer (502).

10. The method for manufacturing an optical anti-counterfeiting element according to claim 1, characterized in that, The thickness of the first reflective layer (3) is greater than 10 nm and less than 80 nm.

11. The method for manufacturing an optical anti-counterfeiting element according to claim 1, characterized in that, It also includes the following steps: After forming the second reflective layer (6), continue with the process of applying other inorganic or organic coatings or layers (7) to achieve other optical anti-counterfeiting functions or auxiliary functions.

12. An optical anti-counterfeiting element, characterized in that, Including: The undulating structure layer (2) has a first region (A) and a second region (B). The first region (A) has a first microstructure, and the second region (B) has a second microstructure. The specific volume of the first microstructure is smaller than that of the second microstructure. The second region (B) has at least two non-adjacent sub-regions, one of which is the first sub-region (B1) and the other is the second sub-region (B2). The first reflective layer (3) is only located on the undulating structure layer (2) in the first region (A). The protective layer (4) is located on the first reflective layer (3). The first ink layer (501) is located on at least the first sub-region (B1). The second ink layer (502) is located on at least the second sub-region (B2). The second reflective layer (6) is located on the first ink layer (501) and the second ink layer (502).

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