Optical anti-counterfeiting elements and optical anti-counterfeiting products

Abstract

The present invention provides an optical anti-counterfeiting element and an optical anti-counterfeiting product. The optical anti-counterfeiting element comprises: a substrate; a micro-relief structure, the micro-relief structure being disposed on one surface of the substrate, the micro-relief structure having protrusions and grooves, the grooves having a high aspect ratio, and the width of the grooves being greater than or equal to 1 micron; and a coating structure, the coating structure being disposed on a side of the micro-relief structure away from the substrate, the coating structure having a thickness at the protrusions different from the thickness at the grooves, so that the optical characteristics at the protrusions and the optical characteristics at the grooves are different; wherein the high aspect ratio of the grooves means that the ratio of the groove depth to the groove width is greater than or equal to 0.5. The present invention solves the problems of high production cost and low manufacturing efficiency of optical anti-counterfeiting elements in the prior art.

Description

Technical Field

[0001] The present invention relates to the field of optical anti-counterfeiting technology, and in particular to an optical anti-counterfeiting element and an optical anti-counterfeiting product. Background Art

[0002] Today, optically variable ink technology is widely used in high-security products such as banknotes, credit cards, passports, securities, and other high-value-added products. Its dynamic optical characteristics and distinct color signatures effectively prevent printing and duplication, effectively preventing counterfeiting.

[0003] The optical color characteristics of microstructures can be divided into two types: the diffraction principle and the interference principle. As for the diffraction principle, it is well known that a holographic grating produces diffraction colors when illuminated by incident light. By appropriately selecting the grating period and the azimuth angle of the grating, different color changes can be achieved at different observation angles. However, the appearance of this grating image is strongly dependent on the lighting conditions. In order to observe the first-order diffraction color, the corresponding anti-counterfeiting element cannot be placed directly opposite the light source. Instead, the anti-counterfeiting element must be placed slightly off the direct connection line to observe the first-order diffraction spot with sufficient light intensity. Therefore, its dependence on the lighting source is too high, resulting in its own obvious application defects.

[0004] Another interference principle with color characteristics utilizes thin-film systems to produce a variety of colors through the interference of incident and transmitted light, with these colors varying with viewing angle. Compared to traditional holographic rainbow colors, this approach offers greater advantages in viewing environment and a significant improvement in optical effects. In this approach, different colors are typically achieved by varying layer thickness (e.g., the thickness of the dielectric interlayer in a three-layer structure: absorber layer / dielectric layer / absorber layer). However, adjusting layer thickness to achieve the desired color requires a very sophisticated, labor-intensive, and inefficient process.

[0005] Creating two or more color effects at specific viewing angles requires precise control of the coating thickness in two or more localized areas. However, in actual production, it is often difficult to precisely control the coating thickness of these optically variable interferometric anti-counterfeiting elements to achieve color matching, resulting in noticeable color differences at the designed matching angle, compromising the anti-counterfeiting effect. Furthermore, the two coatings cannot be achieved in a single vapor deposition process, necessitating additional processes such as precise positioning and printing of protective adhesive, demetallization, and secondary vapor deposition of the optically variable coating, which increases process complexity and cost.

[0006] In other words, the optical anti-counterfeiting elements in the prior art have the problems of high production cost and low manufacturing efficiency. Summary of the Invention

[0007] The main purpose of the present invention is to provide an optical anti-counterfeiting element and an optical anti-counterfeiting product to solve the problems of high production cost and low production efficiency of optical anti-counterfeiting elements in the prior art.

[0008] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, an optical anti-counterfeiting element is provided, comprising: a substrate, a micro-relief structure, the micro-relief structure being arranged on one side surface of the substrate, the micro-relief structure having protrusions and grooves, the grooves having a large aspect ratio, and the width of the grooves being greater than or equal to 1 micron; a coating structure, the coating structure being arranged on a side of the micro-relief structure away from the substrate, the thickness of the coating structure at the protrusions being different from the thickness of the coating structure at the grooves, so that the optical features at the protrusions are different from the optical features at the grooves; wherein the large aspect ratio of the grooves means that the ratio of the depth of the grooves to the width of the grooves is greater than or equal to 0.5.

[0009] Furthermore, the thickness of the plating structure at the protrusion is greater than the thickness of the plating structure at the groove.

[0010] Furthermore, the optical features of the protrusions and the optical features of the grooves have a contrast, and the contrast includes at least one of a color contrast and a brightness contrast.

[0011] Furthermore, the protrusions and grooves are arranged according to a preset rule to form a patterned optical effect.

[0012] Furthermore, the ratio of the groove depth to the groove width is greater than or equal to 0.5 and less than or equal to 3; and / or the size of the groove is greater than or equal to 2 micrometers; and / or the top surface of the protrusion includes at least one of a flat surface and a curved surface.

[0013] Furthermore, the thickness of the coating structure is greater than or equal to 300 nm; and / or the coating structure includes one of a multi-layer coating and a single-layer coating.

[0014] Furthermore, the coating structure includes one of the following: a single-layer metal coating; a multi-layer metal coating; a coating formed by an absorption layer, a low-refractive index medium layer and a reflective layer; a high-refractive index medium layer; a multi-dielectric layer coating formed by stacking a first high-refractive index medium layer, a low-refractive index medium layer and a second high-refractive index medium layer in sequence; a coating formed by stacking an absorption layer, a high-refractive index medium layer and a reflective layer in sequence.

[0015] Furthermore, the material of the reflective layer is a material with high reflectivity; and / or the material of the absorption layer is a material with a refractive index close to the absorption coefficient; and / or the material of the high refractive index medium layer is a medium material with a refractive index greater than 1.7; and / or the material of the low refractive index medium layer is a medium material with a refractive index less than or equal to 1.7.

[0016] Furthermore, the surface of the micro-relief structure is covered with a microstructure.

[0017] Furthermore, the microstructure includes at least one of a one-dimensional submicron structure, a two-dimensional submicron structure, and structural color.

[0018] Furthermore, the optical anti-counterfeiting element includes at least one of a reflective optical system and a transmissive optical system; and / or the depth of the groove is greater than or equal to 2 microns and less than or equal to 15 microns; and / or the width of the groove is greater than or equal to 1 micron and less than or equal to 20 microns.

[0019] Furthermore, the substrate is a colored or colorless film formed of a material selected from the group consisting of polyethylene terephthalate, polyvinyl chloride, polyethylene, polycarbonate, polypropylene, metal, glass, and paper.

[0020] According to another aspect of the present invention, an optical anti-counterfeiting product is provided, characterized in that it includes the above-mentioned optical anti-counterfeiting element.

[0021] Applying the technical solution of the present invention, the optical anti-counterfeiting element includes a substrate, a micro-relief structure and a coating structure. The micro-relief structure is arranged on one side surface of the substrate. The micro-relief structure has protrusions and grooves. The grooves have a large aspect ratio, and the width of the grooves is greater than or equal to 1 micron; the coating structure is arranged on the side of the micro-relief structure away from the substrate, and the thickness of the coating structure at the protrusions is different from the thickness of the coating structure at the grooves, so that the optical characteristics at the protrusions are different from the optical characteristics at the grooves; wherein the large aspect ratio of the groove means that the ratio of the depth of the groove to the width of the groove is greater than or equal to 0.5.

[0022] By setting a micro-relief structure on the substrate, the protrusions and grooves make the surface of the optical anti-counterfeiting element uneven. In the process of forming the coating structure, the evaporation material needs to be evaporated and then deposited on the micro-relief structure. During the deposition of the evaporation material, the speed of atomic deposition is affected by the arrangement of the micro-relief structure, resulting in different numbers of atoms of the evaporated material at the protrusions and grooves of the micro-relief structure. The mutual collision between adjacent atoms causes the deposition path of the atoms to change, thereby changing the deposition speed and forming different optical effects. The advantage of this application is that the optical anti-counterfeiting element can obtain two or more optical color effects through a single evaporation process, without the need for two evaporation coatings. The process flow is simple and greatly reduces the loss of optical effects during the process production process. If the width of the groove is too small, the optical characteristics between the groove and the protrusion are relatively similar, and no different optical effects will be produced. If the aspect ratio of the groove is too small, the optical characteristics formed are also relatively similar. By making the width of the groove of the optical anti-counterfeiting element greater than or equal to 1 micron and having a large aspect ratio, different optical characteristics can be ensured to be formed at the protrusion and groove to increase the anti-counterfeiting effect. By designing the micro-relief structure, the present application can simultaneously form plating structures with different thicknesses on the surface of the micro-relief structure. Specifically, plating structures with different thicknesses are formed at the protrusions and grooves. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0024] Figure 1 A schematic diagram showing the atomic distribution diagram when the optical anti-counterfeiting element according to the first embodiment of the present invention is formed;

[0025] Figure 2 A view showing an angle of the optical anti-counterfeiting element according to the first embodiment of the present invention;

[0026] Figure 3 A view showing an angle of the optical anti-counterfeiting element according to the second embodiment of the present invention;

[0027] Figure 4 A view showing an angle of the optical anti-counterfeiting element according to the third embodiment of the present invention;

[0028] Figure 5 A view showing an angle of an optical anti-counterfeiting element according to a fourth embodiment of the present invention;

[0029] Figure 6 A view at one angle is shown of an optical anti-counterfeiting element according to a fifth embodiment of the present invention.

[0030] The above drawings include the following reference numerals:

[0031] 10. Substrate; 20. Micro-relief structure; 21. Protrusion; 22. Groove; 23. Microstructure; 30. Coating structure. DETAILED DESCRIPTION

[0032] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0033] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by ordinary technicians in the technical field to which this application belongs.

[0034] In the present invention, unless otherwise specified, the directional words used, such as "up, down, top, bottom", usually refer to the directions shown in the drawings, or to the components themselves in the vertical, perpendicular or gravity direction; similarly, for ease of understanding and description, "inside and outside" refer to the inside and outside relative to the outline of each component itself, but the above directional words are not used to limit the present invention.

[0035] In order to solve the problems of high production cost and low manufacturing efficiency of optical anti-counterfeiting elements in the prior art, the present invention provides an optical anti-counterfeiting element and an optical anti-counterfeiting product.

[0036] like Figures 1 to 6 As shown, the optical anti-counterfeiting element includes a substrate 10, a micro-relief structure 20 and a coating structure 30. The micro-relief structure 20 is arranged on one side surface of the substrate 10. The micro-relief structure 20 has a protrusion 21 and a groove 22. The groove 22 has a large aspect ratio, and the width of the groove 22 is greater than or equal to 1 micron; the coating structure 30 is arranged on the side of the micro-relief structure 20 away from the substrate 10. The thickness of the coating structure 30 at the protrusion 21 is different from the thickness of the coating structure 30 at the groove 22, so that the optical characteristics at the protrusion 21 and the optical characteristics at the groove 22 are different; wherein, the large aspect ratio of the groove 22 means that the ratio of the depth of the groove 22 to the width of the groove 22 is greater than or equal to 0.5.

[0037] By setting a micro-relief structure 20 on the substrate 10, the protrusions 21 and the grooves 22 make the surface of the optical anti-counterfeiting element uneven. In the process of forming the coating structure 30, the evaporation material needs to be evaporated and then deposited on the micro-relief structure 20. During the deposition of the evaporation material, the speed of atomic deposition is affected by the arrangement of the micro-relief structure 20, resulting in different numbers of atoms of the evaporated material at the protrusions 21 and the grooves 22 of the micro-relief structure. The mutual collision between adjacent atoms causes the deposition path of the atoms to change, thereby changing the deposition speed and forming different optical effects. The advantage of this application is that the optical anti-counterfeiting element can obtain two or more optical color effects through a single evaporation process, without the need for two evaporation coatings. The process flow is simple, which greatly reduces the loss of optical effects during the process production process. If the width of the groove 22 is too small, the optical characteristics between the groove 22 and the protrusion 21 are relatively similar, and no different optical effects will be produced. If the aspect ratio of the groove 22 is too small, the optical characteristics formed are also relatively similar. By ensuring that the grooves of the optical anti-counterfeiting element have a width greater than or equal to 1 micron and a large aspect ratio, different optical features can be formed at the protrusions 21 and grooves 22, thereby enhancing the anti-counterfeiting effect. The present application, through the design of the micro-relief structure 20, can simultaneously form a coating structure 30 of varying thicknesses on the surface of the micro-relief structure 20. Specifically, a coating structure 30 of varying thicknesses can be formed at the protrusions 21 and grooves 22.

[0038] It should be noted that, under the same conditions, the longer the evaporation time is, the more obvious the difference in optical effects between the protrusions 21 and the grooves 22 is.

[0039] The color change occurs at the groove 22 , and the groove 22 includes the bottom wall and the side wall of the groove 22 . During the deposition process, the number of atoms deposited at the side wall is still less than that of atoms deposited at the protrusion 21 .

[0040] Specifically, the thickness of the coating structure 30 at the protrusion 21 is greater than the thickness of the coating structure 30 at the groove 22. By making the thickness of the coating structure 30 at the protrusion 21 greater than the thickness of the coating structure 30 at the groove 22, it is possible to ensure that the optical effect formed at the protrusion 21 is different from the optical effect formed at the groove 22, thereby achieving the purpose of anti-counterfeiting.

[0041] Due to the arrangement of the micro-relief structure 20 , when depositing the evaporation material, more evaporation material is deposited on the protrusions 21 , while less evaporation material is deposited on the grooves 22 .

[0042] Specifically, the optical features at the protrusions 21 and the optical features at the grooves 22 have a contrast, and the contrast includes at least one of a color contrast and a brightness contrast. In other words, the optical features at the protrusions 21 and the optical features at the grooves 22 have different colors, or the optical features have the same colors but different brightness.

[0043] Specifically, the protrusions 21 are red, while the grooves 22 are yellow. Other colors are possible, depending on the vapor-deposited material and the micro-relief structure. Alternatively, both the protrusions 21 and the grooves 22 may be yellow, with the protrusions 21 being brighter and the grooves 22 being darker. The reverse is also possible, and the color characteristics can be designed based on actual needs.

[0044] Optionally, the protrusions 21 and grooves 22 are arranged according to a predetermined pattern to create a patterned optical effect. In other words, the arrangement of the protrusions 21 and grooves 22 can be designed to create a pattern, and combined with the coating structure 30, a contrast between the pattern and the background can be created, which can be a color contrast or a brightness contrast.

[0045] This contrast can specifically be one or more combinations of the following: The first is that the color changes with viewing angle. For example, the color coating on the optically variable film is a multi-layered coating that generates optical color by the interference of incident and reflected light. The color generated by interference changes with viewing angle. However, at a certain viewing angle, if the surface of the micro-relief structure is not very undulating, the color produced by the protrusions 21 and the grooves 22 is fixed. The second is that the colors of the protrusions 21 and grooves 22 are different and do not change with changes in viewing angle. The third is that the brightness of the light spots at the protrusions 21 and grooves 22 are different.

[0046] Preferably, the ratio of the depth of the groove 22 to the width of the groove 22 is greater than or equal to 0.5 and less than or equal to 3. If the ratio of the depth of the groove 22 to the width of the groove 22 is less than or equal to 0.5, the difference in optical characteristics between the protrusion 21 and the groove 22 is too small, and more vapor deposition material needs to be deposited to highlight the difference in optical characteristics between the protrusion 21 and the groove 22, which is not conducive to the thinness and lightness of the optical anti-counterfeiting element. If the ratio of the depth of the groove 22 to the width of the groove 22 is greater than 3, the height of the micro-relief structure is too high, which is also not conducive to the miniaturization and thinness of the optical anti-counterfeiting element.

[0047] Specifically, the size of the groove 22 is greater than or equal to 2 microns. Limiting the size of the groove 22 to a range of greater than or equal to 2 microns can increase the difference in optical characteristics between the groove 22 and the protrusion 21, and can control the coating structure 30 to be within a relatively thin range to clearly show the difference in optical characteristics between the groove 22 and the protrusion 21, which is conducive to the miniaturization and thinness of the optical anti-counterfeiting element.

[0048] It should be noted that the size of the groove is defined as the distance between adjacent protrusions 21 .

[0049] Optionally, the top surface of the protrusion 21 includes at least one of a plane and a curved surface. The top surface of the protrusion 21 can be a plane, a curved surface, or a surface formed by combining a plane and a curved surface.

[0050] It should be noted that the depth and width of the grooves 22 largely determine their impact on the thickness of the coating structure 30. If the surface topography of the micro-relief structure 20 is not significantly undulating, the deposited color will not be affected. Therefore, the adjustability of the surface topography of the micro-relief structure 20 can be utilized to achieve a variety of optical effects. The micro-relief structure 20 can be either periodic or aperiodic, allowing for the design of dynamic optical effects, stereoscopic optical effects, and even translating and scrolling effects with color and light-dark variations, depending on actual application requirements.

[0051] Preferably, the thickness of the coating structure 30 is greater than or equal to 300 nm. By limiting the thickness of the coating structure 30 to a range of more than 400 nm, the difference between the optical features generated at the protrusions 21 and the grooves 22 is more obvious, facilitating the identification of anti-counterfeiting features.

[0052] Preferably, the thickness of the coating structure 30 is greater than or equal to 300 nm and less than or equal to 800 nm.

[0053] More preferably, the thickness of the plating structure 30 is greater than or equal to 350 nm and less than or equal to 500 nm.

[0054] Optionally, the coating structure 30 includes a multi-layer coating or a single-layer coating. The coating structure 30 can be a single-layer coating or a multi-layer coating, depending on actual usage requirements. Specifically, the single-layer coating can be a single metal coating or a single dielectric layer. The multi-layer coating can be multiple metal coatings, multiple dielectric coatings, or a stack of metal and dielectric coatings.

[0055] More specifically, the coating structure 30 includes one of the following: a single-layer metal coating; a multi-layer metal coating; a coating formed by an absorption layer, a low-refractive index medium layer and a reflective layer; a high-refractive index medium layer; a multi-dielectric layer coating formed by stacking a first high-refractive index medium layer, a low-refractive index medium layer and a second high-refractive index medium layer in sequence; a coating formed by stacking an absorption layer, a high-refractive index medium layer and a reflective layer in sequence.

[0056] Specifically, the reflective layer is made of a material with a high reflectivity, such as gold, silver, copper, or aluminum. The absorption layer is made of a material with a refractive index close to the absorption coefficient. This can be a semi-metallic material, such as silicon or germanium, or a metal or its alloy, such as chromium, copper, nickel, or nickel-chromium alloy. The high-refractive-index dielectric layer is made of a material with a refractive index greater than 1.7, such as zinc sulfide or titanium dioxide. The low-refractive-index dielectric layer is made of a material with a refractive index less than or equal to 1.7, such as magnesium fluoride, silicon dioxide, or cryolite.

[0057] Among them, high reflectivity materials refer to materials with a refractive index greater than 1.7

[0058] In an optional embodiment, the surface of the micro-relief structure 20 is covered with a microstructure 23. The surface of the micro-relief structure 20 may also be covered with a microstructure to increase the difference between the optical features at the protrusions 21 and the optical features at the grooves 22.

[0059] Of course, the microstructure 23 can be provided only on the protrusion 21 or only on the groove 22 according to specific needs. It can also be provided on both the protrusion 21 and the groove 22, and the microstructure 23 on the protrusion 21 and the microstructure 23 on the groove 22 can be the same or different.

[0060] Specifically, the microstructure 23 includes at least one of a one-dimensional submicron structure, a two-dimensional submicron structure, and a structural color. It should be noted that the inclusion of structural color in a microstructure is independent of pigment coloration and is an optical effect caused by a submicroscopic structure. Here, the inclusion of structural color in a microstructure refers to a microstructure that can produce structural color.

[0061] Optionally, the optical anti-counterfeiting element includes at least one of a reflective optical system and a transmissive optical system. In the present application, the optical anti-counterfeiting element can be a reflective optical system or a transmissive optical system, and of course, it can also transmit part of the light and reflect part of the light.

[0062] Specifically, the depth of the groove 22 is greater than or equal to 2 microns and less than or equal to 15 microns. If the depth of the groove 22 is less than 2 microns, the depth of the groove 22 is too small, which is not conducive to generating a difference in optical characteristics between the protrusion 21 and the groove 22. If the depth of the groove 22 is greater than 15 microns, the depth of the groove 22 is too large, which is not conducive to the miniaturization of the optical anti-counterfeiting element. However, limiting the depth of the groove 22 to a range of 2 microns to 15 microns can ensure that the optical anti-counterfeiting element generates a difference in optical characteristics between the groove 22 and the protrusion 21, and can also ensure that the optical anti-counterfeiting element is lightweight and thin.

[0063] Preferably, the depth of the groove 22 is greater than or equal to 3 micrometers and less than or equal to 6 micrometers.

[0064] Preferably, the depth of the groove 22 may be 3 micrometers, 4 micrometers, 5 micrometers, 6 micrometers, 7 micrometers, 8 micrometers, 9 micrometers, 10 micrometers, 11 micrometers, 12 micrometers, 13 micrometers, or 14 micrometers.

[0065] Specifically, the width of the groove 22 is greater than or equal to 1 micron and less than or equal to 20 microns. If the width of the groove 22 is less than 1 micron, it is too small, which is not conducive to generating optical feature differences. If the width of the groove 22 is greater than 20 microns, it is not conducive to miniaturization of the optical anti-counterfeiting element. Limiting the width of the groove 22 to the range of 1 to 20 microns can ensure that the optical feature differences between the groove 22 and the protrusion 21 are generated, and can also ensure that the optical anti-counterfeiting element is lightweight and thin.

[0066] Preferably, the width of the groove 22 is greater than or equal to 2 micrometers and less than or equal to 4 micrometers.

[0067] Preferably, the width of the groove 22 can be 2 microns, 3 microns, 4 microns, 5 microns, 6 microns, 7 microns, 8 microns, 9 microns, 10 microns, 11 microns, 12 microns, 13 microns, 14 microns, 15 microns, 16 microns, 17 microns, 18 microns, or 19 microns.

[0068] Optionally, the substrate 10 is a colored or colorless film formed of a material selected from the group consisting of polyethylene terephthalate, polyvinyl chloride, polyethylene, polycarbonate, polypropylene, metal, glass, and paper.

[0069] Optical anti-counterfeiting products include the above-mentioned optical anti-counterfeiting elements, and specifically can be various high-security products and high-value-added products such as banknotes, credit cards, ID cards, passports and securities.

[0070] The micro-relief structure 20 in the present application is a large-sized grating structure, which is randomly arranged and has no specific periodicity. The structure is composed of irregular protrusions 21 and grooves 22. The micro-relief structure 20 can not only affect the color change, but also arrange its position and morphology according to a specific rule to form stripes with light and dark changes and patterned dynamic and three-dimensional images, effectively increasing the anti-counterfeiting ability of the optical anti-counterfeiting element.

[0071] The cross-sectional shape of the groove 22 can be any of the following: rectangular, sawtooth, triangular, or sinusoidal. Of course, the groove 22 can be filled with a microstructure, such as a one-dimensional submicron structure, a two-dimensional submicron structure, or a structural color, combined with metal plating or optically variable coating, to create a color contrast with the area outside the groove 22.

[0072] In an optional embodiment, the coating structure 30 can be an interference-type stacked structure and form a Fabry-Perot resonant cavity, which has a selective effect on the incident white light, and the outgoing light only contains certain bands to form a specific color; when the incident angle changes, the relative optical path changes, the interference band changes, and the color also changes, forming a light-changing effect, such as the traditional light-changing film structure, "reflection layer / low refractive index medium layer / absorption layer"; or it can be a color coating with a structure of "reflection layer / high refractive index medium layer / absorption layer"; or it can be a stack of medium layers with different refractive indices, such as a "high refractive index medium layer / low refractive index medium layer / high refractive index medium layer" structure. Among them, the reflective layer is a material with high reflectivity, such as gold, silver, copper, aluminum, etc.; the absorption layer material requires a material with a refractive index close to the absorption coefficient, which can be a semi-metallic material, such as silicon, germanium, etc., or a metal material or its alloy, such as chromium, copper, nickel, nickel-chromium alloy, etc.; the high refractive index dielectric layer is a dielectric material with a refractive index higher than 1.7, such as zinc sulfide, titanium dioxide, etc.; the low refractive index dielectric layer is a dielectric material with a refractive index less than or equal to 1.7, such as magnesium fluoride, silicon dioxide, cryolite, etc.

[0073] Example 1

[0074] exist Figure 1 and Figure 2 In the illustrated embodiment, the coating structure 30 is a color-variable thin film composed of Cr / SiO2 / Al. The Al layer is closely attached to the surface of the micro-relief structure 20, and the thicknesses of the layers are 5nm / 430nm / 60nm, respectively. The color characteristics of the protrusions 21 of the micro-relief structure 20 shift from magenta to green as the viewing angle changes, while the color characteristics of the grooves 22 shift from golden yellow to blue as the viewing angle changes. In this embodiment, the grooves 22 are 2μm wide and 4μm high.

[0075] Example 2

[0076] The difference from the first embodiment is that the thickness of the coating at the groove 22 is different, so that the color can be observed on the back side of the substrate 10 .

[0077] exist Figure 3 In the illustrated embodiment, the groove 22 has a height of 10 μm and a width of 4 μm. During the evaporation process, the coating structure 30 formed on the protrusion 21 and the groove 22 has different thicknesses, resulting in different coating colors. The coating structure 30 on the protrusion 21 is thicker than the coating structure 30 on the groove 22. When the coating structure 30 at the groove 22 is sufficiently thin, the color can be observed from the back side of the substrate 10. After the groove 22 is filled with a subwavelength structure, the transmittance is increased, making the color more easily observed in the direction of transmitted light.

[0078] In this embodiment, the coating structure 30 is a color-variable thin film composed of Cr / SiO2 / Al, with thicknesses of 5nm / 430nm / 60nm, respectively. The color reflection at the groove 22 changes from golden yellow to blue as the angle changes. When observed in the transmission direction, the color characteristic is blue. Since the color is weaker when observed in the transmission direction, the color change is not observed.

[0079] It should be noted that the thickness of each layer of the plating structure 30 is the thickness at the protrusion 21 .

[0080] Example 3

[0081] The difference from the first embodiment is that at least a portion of the surface of the protrusion 21 is a curved surface.

[0082] exist Figure 4 In the specific embodiment shown, at least part of the surface of the protrusion 21 is a curved surface. Of course, the coating structure 30 covering the micro-relief structure 20 also has an adaptive curved surface, which is conducive to the design of more optical effects, such as dynamic light-changing effects.

[0083] Example 4

[0084] The difference from the first embodiment is that the surface of the protrusion 21 has a microstructure 23 .

[0085] exist Figure 5 In the specific embodiment shown, a microstructure 23 is provided at the protrusion 21 of the micro-relief structure 20. The microstructure 23 is a subwavelength structure. The subwavelength structure can be a one-dimensional submicron structure, a two-dimensional submicron structure, or a structural color. It can also be combined with a metal coating or a photovariable coating to be colored to form a color contrast with the area not covered by the subwavelength structure.

[0086] Example 5

[0087] The difference from the first embodiment is that the surface of the groove 22 has a microstructure 23 .

[0088] exist Figure 5 In the specific embodiment shown, a subwavelength structure is provided at the groove 22, and the subwavelength structure can be one of a one-dimensional submicron structure, a two-dimensional submicron structure, and a structural color. It can also be combined with a metal coating or a photovariable coating to be colored to form a color contrast with the area not covered by the subwavelength structure.

[0089] Obviously, the embodiments described above are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0090] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, tasks, devices, components and / or combinations thereof.

[0091] It should be noted that the terms "first," "second," and the like in the specification and claims of this application and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein.

[0092] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. An optical anti-counterfeiting element, characterized in that: include: substrate (10), A micro-relief structure (20), the micro-relief structure (20) being arranged on a side surface of the substrate (10), the micro-relief structure (20) having a protrusion (21) and a groove (22), the groove (22) having a large aspect ratio, and the width of the groove (22) being greater than or equal to 1 micron; a coating structure (30), the coating structure (30) being arranged on a side of the micro-relief structure (20) away from the substrate (10), the thickness of the coating structure (30) at the protrusion (21) being different from the thickness of the coating structure (30) at the groove (22), so that the optical characteristics at the protrusion (21) and the optical characteristics at the groove (22) are different; The large aspect ratio of the groove (22) means that the ratio of the depth of the groove (22) to the width of the groove (22) is greater than or equal to 0.5; The thickness of the plating structure (30) at the protrusion (21) is greater than the thickness of the plating structure (30) at the groove (22); The thickness at the protrusion (21) refers to the thickness of the top surface of the protrusion (21), and the coating structure (30) is formed by an evaporation process.

2. The optical anti-counterfeiting element according to claim 1, characterized in that: The optical features at the protrusion (21) and the optical features at the groove (22) have a contrast, and the contrast includes at least one of a color contrast and a brightness contrast.

3. The optical anti-counterfeiting element according to claim 1, characterized in that: The protrusions (21) and the grooves (22) are arranged according to a preset rule to form a patterned optical effect.

4. The optical anti-counterfeiting element according to claim 1, characterized in that: The ratio of the depth of the groove (22) to the width of the groove (22) is greater than or equal to 0.5 and less than or equal to 3; and / or The size of the groove (22) is greater than or equal to 2 micrometers, wherein the size of the groove (22) is the distance between adjacent protrusions (21); and / or The top surface of the protrusion (21) includes at least one of a flat surface and a curved surface.

5. The optical anti-counterfeiting element according to any one of claims 1 to 4, characterized in that: The thickness of the coating structure (30) is greater than or equal to 300 nm; and / or The coating structure (30) includes one of a multi-layer coating and a single-layer coating.

6. The optical anti-counterfeiting element according to any one of claims 1 to 4, characterized in that: The coating structure (30) comprises one of the following: a single-layer metal coating; a multi-layer metal coating; a coating formed by an absorption layer, a low-refractive-index medium layer, and a reflective layer; a high-refractive-index medium layer; A multi-dielectric layer coating is formed by stacking a first high-refractive index dielectric layer, a low-refractive index dielectric layer and a second high-refractive index dielectric layer in sequence; a coating is formed by stacking an absorption layer, a high-refractive index dielectric layer and a reflective layer in sequence.

7. The optical anti-counterfeiting element according to claim 6, characterized in that: The reflective layer is made of a material with high reflectivity; and / or The material of the absorption layer is a material with a refractive index close to the absorption coefficient; and / or The material of the high refractive index medium layer is a medium material with a refractive index greater than 1.7; and / or The material of the low-refractive-index medium layer is a medium material with a refractive index less than or equal to 1.

7.

8. The optical anti-counterfeiting element according to any one of claims 1 to 4, characterized in that: The surface of the micro-relief structure (20) is covered with a microstructure (23).

9. The optical anti-counterfeiting element according to claim 8, characterized in that: The microstructure (23) includes at least one of a one-dimensional submicron structure, a two-dimensional submicron structure, and a structural color.

10. The optical anti-counterfeiting element according to any one of claims 1 to 4, characterized in that: The optical anti-counterfeiting element includes at least one of a reflective optical system and a transmissive optical system; and / or The depth of the groove (22) is greater than or equal to 2 micrometers and less than or equal to 15 micrometers; and / or The width of the groove (22) is greater than or equal to 1 micron and less than or equal to 20 microns.

11. The optical anti-counterfeiting element according to any one of claims 1 to 4, characterized in that: The substrate (10) is a colored or colorless film formed from a material selected from the group consisting of polyethylene terephthalate, polyvinyl chloride, polyethylene, polycarbonate, polypropylene, metal, glass, and paper.

12. An optical anti-counterfeiting product, characterized in that: The optical anti-counterfeiting element comprises the optical anti-counterfeiting element according to any one of claims 1 to 11.

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