CN116100979A

CN116100979A - Optical anti-counterfeiting element, anti-counterfeiting product and manufacturing method of optical anti-counterfeiting element

Info

Publication number: CN116100979A
Application number: CN202111335319.6A
Authority: CN
Inventors: 胡春华; 李欣毅; 吴远启; 叶东
Original assignee: Zhongchao Special Security Technology Co Ltd; China Banknote Printing and Minting Group Co Ltd
Current assignee: Zhongchao Special Security Technology Co Ltd; China Banknote Printing and Minting Group Co Ltd
Priority date: 2021-11-11
Filing date: 2021-11-11
Publication date: 2023-05-12
Also published as: WO2023082732A1

Abstract

The invention provides an optical anti-counterfeiting element, an anti-counterfeiting product and a manufacturing method of the optical anti-counterfeiting element. An optical anti-counterfeiting element comprising a substrate layer and an optical layer, wherein the optical layer is arranged on one side of the substrate layer and is connected with the substrate layer, the optical layer comprises a microstructure layer, and the microstructure layer comprises: a first region having a plurality of first microstructures; the second area is provided with a plurality of second microstructures, the first area is provided with white features, the second area is provided with interference optical color changing features, and the specific volume of the second microstructures is larger than that of the first microstructures when the second area is observed from one side of the optical anti-counterfeiting element. The invention solves the problem of poor anti-counterfeiting performance of the optical anti-counterfeiting element in the prior art.

Description

Optical anti-counterfeiting element, anti-counterfeiting product and manufacturing method of optical anti-counterfeiting element

Technical Field

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

Background

In order to prevent forgery by means of scanning and copying, optical security elements including optical security technology are widely used in various high-security or high-added value printed matters such as banknotes, credit cards, passports, securities, product packages, etc., and although the optical security elements improve the security performance, the security performance of the optical security elements is still easy to imitate.

That is, the optical anti-counterfeiting element in the prior art has the problem of poor anti-counterfeiting performance.

Disclosure of Invention

The invention mainly aims to provide an optical anti-counterfeiting element, an anti-counterfeiting product and a manufacturing method of the optical anti-counterfeiting element, so as to solve the problem that the optical anti-counterfeiting element in the prior art has poor anti-counterfeiting performance.

In order to achieve the above object, according to one aspect of the present invention, there is provided an optical security element comprising a base layer and an optical layer disposed on one side of the base layer and connected to the base layer, the optical layer comprising a microstructured layer comprising: a first region having a plurality of first microstructures; the second area is provided with a plurality of second microstructures, the first area is provided with white features, the second area is provided with interference optical color changing features, and the specific volume of the second microstructures is larger than that of the first microstructures when the second area is observed from one side of the optical anti-counterfeiting element.

Further, the optical layer further includes: the metal layer is connected with one side of the first area far away from the basal layer; and the interference light variable layer is connected with at least one side of the second area away from the basal layer.

Further, the optical layer further comprises a protective layer, and the protective layer is connected with one side of the metal layer away from the substrate layer.

Further, the interference light variable layer is connected with one side of the protective layer away from the metal layer.

Further, the interference optically variable layer comprises an absorption layer, a dielectric layer and a reflecting layer which are sequentially arranged in a stacked manner, and the absorption layer is at least connected with one side, far away from the substrate layer, of the second area.

Further, the material of the absorption layer comprises at least one of nickel, chromium, aluminum, silver, copper, tin and titanium; and/or the material of the dielectric layer comprises at least one of magnesium fluoride, silicon dioxide, zinc sulfide, titanium nitride, titanium dioxide, titanium monoxide, titanium oxide, tantalum pentoxide, niobium pentoxide, cerium dioxide, bismuth trioxide, chromium trioxide, iron oxide, hafnium dioxide or zinc oxide; and/or the material of the reflective layer comprises at least one of aluminum, silver, tin, nickel, titanium.

Further, the metal layer comprises at least one of aluminum, silver, tin, nickel and titanium; and/or the thickness of the metal layer is greater than 10nm and less than or equal to 80nm.

Further, the specific volume of the first microstructure is more than or equal to 0 and less than or equal to 0.5um ³ /um ² The method comprises the steps of carrying out a first treatment on the surface of the And/or the specific volume of the second microstructure is in the range of greater than 0.4um ³ /um ² And is less than 2um ³ /um ² 。

Further, the first microstructures are all achromatic microstructures.

Further, at least two of the plurality of achromatic microstructures are different in size, at least two of the plurality of achromatic microstructures are different in height, and the achromatic microstructures are protrusions or grooves.

Further, the length of the achromatic microstructure is more than 1um and less than 10um; and/or the depth of the achromatic microstructure is greater than 0.1um and less than 5um.

Further, the achromatic microstructure is a micro-mirror, and the length of the micro-mirror is more than or equal to 5um and less than or equal to 10um; and/or the depth of the micro-mirror is greater than 1um and less than or equal to 4um.

Further, the first region includes: the first subarea is continuously arranged around the periphery of the second area, and the first microstructure in the first subarea is a achromatic microstructure; the second subarea is continuously arranged around the periphery of the first subarea, and the first microstructure in the second subarea is a non-achromatic white microstructure.

Further, the plurality of non-achromatic white microstructures are arranged periodically; or a plurality of non-achromatic white microstructures are arranged in a non-periodic manner.

Further, the cross-sectional structure of the non-achromatic microstructure along the extending direction is: at least one of a flat structure, a sine structure, a rectangular grating structure, a trapezoid grating structure, a blazed grating structure and an arc grating structure.

Further, the plurality of second microstructures are periodically arranged; or the plurality of second microstructures are arranged in a non-periodic manner.

Further, the cross-sectional structure of the second microstructure along the extension direction is: at least one of a flat structure, a sine structure, a rectangular grating structure, a trapezoid grating structure, a blazed grating structure and an arc grating structure.

According to another aspect of the present invention there is provided a security product comprising an optical security element as described above.

Further, the anti-counterfeiting product further comprises a supporting body, the optical anti-counterfeiting element is arranged on the supporting body, and at least part of the surface of the supporting body, which supports the optical anti-counterfeiting element, is white.

According to another aspect of the present invention, there is provided a method for manufacturing an optical security element, where the optical security element is manufactured by using the method for manufacturing an optical security element, the method for manufacturing an optical security element includes: step S10: forming a microstructure layer with a first area and a second area on the surface of the substrate layer, forming a first microstructure on the first area, and forming a second microstructure with a specific volume larger than that of the first microstructure on the second area; step S20: forming a metal layer on the surface of the microstructure layer far away from the basal layer; step S30: forming a protective layer for protecting the first area on the surface of the metal layer far away from the optical layer; step S40: removing the metal layer at the second region; step S50: an interference optically variable layer is formed on a surface of the substrate layer.

By applying the technical scheme of the invention, the optical anti-counterfeiting element comprises a substrate layer and an optical layer, wherein the optical layer is arranged on one side of the substrate layer and connected with the substrate layer, the optical layer comprises a microstructure layer, the microstructure layer comprises a first area and a second area, and the first area is provided with a plurality of first microstructures; the second region has a plurality of second microstructures, the first region has a white feature, and the second region has an interference optical color change feature, when viewed from a side of the optical security element, the second microstructures having a specific volume greater than the specific volume of the first microstructures.

The first area and the second area are arranged to enable the optical characteristics of the two areas to be different, the first area with white characteristics plays a role of setting off, and the second area with the interference optical color-changing characteristics can present different color effects at different observation angles. The second area with the interference optical color-changing characteristic is also in a preset shape, when the optical anti-counterfeiting element is obliquely observed, only a specific image has a color-changing effect, and other areas are white, so that the optical anti-counterfeiting element has extremely strong visual characteristics and anti-counterfeiting performance. The specific volume of the second microstructure is larger than that of the first microstructure, so that the second microstructure occupies larger space under the condition of adopting the same weight, and the sizes of the microstructures of the first region and the second region are different on the basis of not increasing the weight of the optical anti-counterfeiting element, so that the first region and the second region generate different optical characteristics.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention. In the drawings:

FIG. 1 is a schematic diagram showing the structure of an optical security element according to a first embodiment of the present invention;

FIG. 2 shows an angled cross-sectional view of the optical security element of FIG. 1;

FIG. 3 is a schematic diagram of an optical security element according to a second embodiment of the present invention;

fig. 4 shows an angled cross-sectional view of the optical security element of fig. 3.

Wherein the above figures include the following reference numerals:

10. a base layer; 20. an optical layer; 30. a microstructure layer; 31. a first region; 311. a first microstructure; 312. a first sub-region; 313. a second sub-region; 32. a second region; 321. a second microstructure; 40. a metal layer; 50. an interference light variable layer; 51. an absorption layer; 52. a dielectric layer; 53. a reflective layer; 60. a protective layer; 70. functional coating.

Detailed Description

It should be noted that, in the case of no conflict, the embodiments and features in the embodiments may be combined with each other. The invention will be described in detail below with reference to the drawings in connection with embodiments.

It is noted that all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs unless otherwise indicated.

In the present invention, unless otherwise indicated, terms of orientation such as "upper, lower, top, bottom" are used generally with respect to the orientation shown in the drawings or with respect to the component itself in the vertical, upright or gravitational direction; also, for ease of understanding and description, "inner and outer" refers to inner and outer relative to the profile of each component itself, but the above-mentioned orientation terms are not intended to limit the present invention.

In order to solve the problem of poor anti-counterfeiting performance of the optical anti-counterfeiting element in the prior art, the invention provides the optical anti-counterfeiting element, an anti-counterfeiting product and a manufacturing method of the optical anti-counterfeiting element.

In the existing optical anti-counterfeiting technology, optical effects formed by microstructures, such as diffraction, non-diffraction and the like, are widely applied due to high brightness and obvious dynamic effect. Microstructured optical security technologies in order to increase the brightness of an image, metallic reflective layers, such as aluminum, are typically used. Among them, the most widely used optical anti-counterfeiting technology, i.e. holographic technology, is the optical technology developed by utilizing diffraction effects formed by microstructures. The fifth set of 1999 edition 5-element, 10-element, 20-element, 50-element and 100-element anti-counterfeiting lines adopts holographic technology. In addition, multilayer interference optically variable techniques are becoming more and more attractive because of their different color effects at different viewing angles. The color change of the interference light change effect is definite and describable, for example, the front view is A color, the oblique view is B color, and thus the anti-counterfeiting performance is higher than that of the hologram. The multilayer interference light transformation technology generally adopts a vapor deposition method to realize the vapor deposition of a multilayer interference coating.

Classical multilayer interference coatings generally comprise a reflective layer, a dielectric layer and an absorptive layer. The reflective layer is generally made of a high brightness metal material, the dielectric layer is generally made of a transparent inorganic or organic material, and the absorptive layer is also called a semitransparent layer and is generally made of a thinner metal material with good absorptivity. The fifth set of 2015 edition 100 yuan, 2019 edition 10 yuan, 20 yuan and 50 yuan RMB safety line adopts a multilayer interference light variation technology, and is in a magenta shape when being observed in front view and in a green shape when being observed in an inclined way. In particular, the 50 Yuan RMB safety line adopts the technology of combining an optical microstructure and an interference light change layer 50, so that the combined anti-counterfeiting characteristic of combining a rolling bar effect and an interference light change effect which are displayed by the visible microstructure when obliquely observed.

The optical anti-counterfeiting element of the application combines an optical microstructure with the interference optically variable layer 50, the shape of the area with the interference optically variable color feature is a preset shape, for example, letters or numbers or other images with specific information, and then the application of the interference optically variable coating can achieve the effect of complement, namely, oblique observation, and the specific images have the color-changing effect. It is conceivable that if in an optical security element only a specific image exhibits a color change effect (i.e. the interference light-changing coating is strictly located) and the other areas are white, the optical security element is applied on a substrate with white characteristics (e.g. banknote paper) and has very strong visual characteristics and security properties.

As shown in fig. 1 to 4, the optical security element comprises a substrate layer 10 and an optical layer 20, the optical layer 20 is disposed on one side of the substrate layer 10 and connected to the substrate layer 10, the optical layer 20 comprises a microstructure layer 30, the microstructure layer 30 comprises a first region 31 and a second region 32, and the first region 31 has a plurality of first microstructures 311; the second region 32 has a plurality of second microstructures 321, the first region 31 has a white feature, and the second region 32 has an interferometric optical color change feature, when viewed from a side of the optical security element, the specific volume of the second microstructures 321 being greater than the specific volume of the first microstructures 311.

By arranging the first region 31 and the second region 32, the optical characteristics of the two regions are different, while the first region 31 with white characteristic plays a role of setting off, and the second region 32 with the interference optical color change characteristic can present different color effects at different observation angles. The second region 32 having the interference optical color change feature is also of a predetermined shape, and when the optical security element is obliquely viewed, only a specific image has a color change effect, while other regions are white, and have extremely strong visual features and security properties. The specific volume of the second microstructure 321 is larger than the specific volume of the first microstructure 311, so that the second microstructure 321 occupies a larger space with the same weight, and the sizes of the microstructures of the first region 31 and the second region 32 are different on the basis of not increasing the weight of the optical security element, so that the first region 31 and the second region 32 generate different optical characteristics.

Example 1

In the particular embodiment shown in fig. 1, the second region 32 has an interference optical color change feature and the second region 32 is a five-pointed star region having a relief and having a color change feature that varies with tilt angle, the color change region being severely coincident with the five-pointed star region having the relief feature. The lines of the tips of the five-pointed star areas may be very fine, e.g. less than 20um. If the optical anti-counterfeiting element is stuck on a white protected product, the five-pointed star is abnormal and striking, and the embossment sense and the color change effect are added, so that the product has excellent anti-counterfeiting performance.

As shown in fig. 2, the thickness of the second region 32 is greater than the thickness of the first region 31. This causes the second region 32 to protrude from the first region 31, making the interference optical color change feature at the second region 32 more pronounced.

As shown in fig. 2, optical layer 20 further includes a metal layer 40 and an interference light-altering layer 50, metal layer 40 being connected to a side of first region 31 remote from substrate layer 10; the interference light varying layer 50 is connected to at least the side of the second region 32 remote from the substrate layer 10. The provision of the metal layer 40 enables the first microstructures 311 on the first region 31 to exhibit a higher whiteness, enabling white features at the first region 31. The interference optically variable layer 50 is disposed at the second region 32, so that the second region 32 can realize the interference optically variable feature, and since the second region 32 has no metal layer 40, the interference optically variable feature at the second region 32 is not affected, so that the first region 31 and the second region 32 have obvious distinction, and the anti-counterfeiting performance of the optical anti-counterfeiting element is increased.

As shown in fig. 2, optical layer 20 further includes a protective layer 60, protective layer 60 being coupled to a side of metal layer 40 remote from substrate layer 10. The protective layer 60 does not provide an additional optical effect and protects the metal layer 40.

As shown in fig. 2, the interference light variation layer 50 is further disposed at the first region 31, and the interference light variation layer 50 is connected to a side of the protection layer 60 away from the metal layer 40. This arrangement facilitates the formation of an interference light modifying layer 50 on the optical security element, although the interference light modifying layer 50 is also present at the first region 31, due to the presence of the metal layer 40 at the first region 31, the interference light modifying layer 50 at the first region 31 under the influence of the metal layer 40 will not produce an interference light modifying feature, but will only produce a white feature at the first region 31.

As shown in fig. 2, the interference light variable layer 50 includes an absorption layer 51, a dielectric layer 52, and a reflection layer 53, which are sequentially stacked, and the absorption layer 51 is connected to at least one side of the second region 32 away from the base layer 10. The reflective layer is typically made of a high brightness metallic material and the dielectric layer 52 is typically made of a transparent inorganic or organic material, and the absorber layer 51, also referred to as a translucent layer, is typically made of a thinner, well-absorbing metallic material to form an interference optical color change feature in the second region.

Specifically, the material of the absorbing layer 51 includes at least one of nickel, chromium, aluminum, silver, copper, tin, and titanium. The material of the absorbing layer 51 may be one of nickel, chromium, aluminum, silver, copper, tin, and titanium, or may be a mixture of nickel, chromium, aluminum, silver, copper, tin, and titanium.

Specifically, the material of the dielectric layer 52 includes at least one of magnesium fluoride, silicon dioxide, zinc sulfide, titanium nitride, titanium dioxide, titanium monoxide, titanium oxide, tantalum pentoxide, niobium pentoxide, cerium oxide, bismuth trioxide, chromium trioxide, iron oxide, hafnium oxide, or zinc oxide. The material of the dielectric layer 52 may be one of magnesium fluoride, silicon dioxide, zinc sulfide, titanium nitride, titanium dioxide, titanium monoxide, titanium oxide, tantalum pentoxide, niobium pentoxide, cerium oxide, bismuth trioxide, chromium trioxide, iron oxide, hafnium oxide, or zinc oxide, or may be a mixture of several of magnesium fluoride, silicon dioxide, zinc sulfide, titanium nitride, titanium dioxide, titanium oxide, tantalum pentoxide, niobium pentoxide, cerium oxide, bismuth trioxide, chromium trioxide, iron oxide, hafnium oxide, or zinc oxide.

Specifically, the material of the reflective layer 53 includes at least one of aluminum, silver, tin, nickel, and titanium. The material of the reflective layer 53 may be one of aluminum, silver, tin, nickel, and titanium, or may be a mixture of aluminum, silver, tin, nickel, and titanium.

Specifically, the metal layer 40 includes at least one of aluminum, silver, tin, nickel, and titanium. The material of the metal layer 40 may be one of aluminum, silver, tin, nickel and titanium, or may be a mixture of aluminum, silver, tin, nickel and titanium, which is only required to ensure that the metal layer 40 has high reflectivity.

Specifically, the thickness of the metal layer 40 is greater than 10nm and equal to or less than 80nm. If the thickness of the metal layer 40 is less than 10nm, the thickness of the metal layer 40 is too small to be uniformly coated, and the metal layer 40 is easily removed. If the thickness of the metal layer 40 is greater than 80nm, the thickness of the metal layer 40 is excessively large, fastness with the microstructure layer 30 is poor, and cost increases. The thickness of the metal layer 40 is limited to a range of 10nm to 80nm, so that the metal layer 40 is not easy to remove, and the firmness of the adhesion of the metal layer 40 and the microstructure layer 30 is ensured.

Specifically, the specific volume of the first microstructure 311 is greater than or equal to 0 and less than or equal to 0.5um ³ /um ² . If the specific volume of the first microstructure 311 is greater than 0.5um ³ /um ² The specific volume of the first microstructure 311 is too large and the first microstructure 311 is relatively large under the same mass, which is disadvantageous for generating white features.

Specifically, the specific volume of the second microstructure 321 is in the range of greater than 0.4um ³ /um ² And is less than 2um ³ /um ² . If the specific volume of the second microstructure 321 is less than 0.4um ³ /um ² The specific volume of the second microstructure 321 is too small, so that the second microstructure 321 has too small volume under the condition of the same mass, which is unfavorable for the relief feature generated by the second microstructure 321, if the specific volume of the second microstructure 321 is larger than 2um ³ /um ² . The second microstructure 321 is oversized for the same mass, which is detrimental to the interference optically variable layer 50 in producing the interference optically variable feature. While controlling the specific volume of the second microstructure 321 to be 0.4um ³ /um ² And is less than 2um ³ /um ² While ensuring good interferometric photochromic characteristics at the second region 32.

Specifically, the first microstructures 311 are all achromatic microstructures. By setting the first microstructure 311 to be a achromatic microstructure, light of a specific color can be eliminated so that the first region 31 exhibits a white feature.

Specifically, at least two of the plurality of achromatic microstructures are different in size, at least two of the plurality of achromatic microstructures are different in height, and the achromatic microstructures are protrusions or grooves. This allows a relatively large degree of freedom in the design of the first microstructure 311 at the first region 31, which is advantageous for the fabrication of the first microstructure 311.

Specifically, the length of the achromatic microstructure is more than 1um and less than 10um. If the length of the achromatic microstructure is less than 1um, the length of the achromatic microstructure is too small, which is unfavorable for manufacturing the achromatic microstructure. If the length of the achromatic microstructure is more than 10um, the length of the achromatic microstructure becomes too large, and the achromatic effect is poor. The length of the decoloring microstructure is limited to be 1um to 10um, so that the decoloring effect of the decoloring microstructure is ensured and the manufacturing of the decoloring microstructure is facilitated.

Specifically, the depth of the achromatic microstructure is greater than 0.1um and less than 5um. If the depth of the achromatic microstructure is less than 0.1um, the height of the achromatic microstructure is too small, which is not favorable for manufacturing the achromatic microstructure. If the depth of the achromatic microstructure is larger than 5um, the height of the achromatic microstructure is too large, which is unfavorable for miniaturization, light weight and thinning of the optical anti-counterfeiting element. The depth of the achromatic microstructure is limited to be in the range of 0.1um to 5um, so that the manufacturing of the achromatic microstructure is facilitated, and meanwhile, the light and thin optical anti-counterfeiting element is ensured.

Specifically, the achromatic microstructure is a micro-mirror, and the length of the micro-mirror is 5um or more and 10um or less. The achromatic white microstructure is arranged as a micro-mirror, so that the reflection characteristic of light can be achieved, the self-characteristics of the micro-mirror can eliminate light with specific colors, and finally the micro-mirror presents the characteristic of white.

Specifically, the depth of the micro-mirror is greater than 1um and less than or equal to 4um.

Alternatively, the plurality of second microstructures 321 are arranged periodically, that is, the plurality of second microstructures 321 may be arranged periodically in a predetermined period, for example, in a matrix.

Of course, the plurality of second microstructures 321 may also be arranged non-periodically, and the plurality of second microstructures 321 are arranged non-periodically. That is, the plurality of second microstructures 321 may be randomly arranged, and not regularly circulated.

Specifically, the cross-sectional structure of the second microstructure 321 along the extension direction is at least one of a flat structure, a sinusoidal structure, a rectangular grating structure, a trapezoidal grating structure, a blazed grating structure, and an arc-shaped grating structure. The second microstructure 321 may be a single structure form of a flat structure, a sinusoidal structure, a rectangular grating structure, a trapezoidal grating structure, a blazed grating structure, or an arc-shaped grating structure, or may be a combination of several structures.

The security product comprises the optical security element. The anti-counterfeiting product with the optical anti-counterfeiting element has the advantages of high anti-counterfeiting performance and difficult imitation.

Specifically, the anti-counterfeiting product further comprises a supporting body, the optical anti-counterfeiting element is arranged on the supporting body, and at least part of the surface of the supporting body, which supports the optical anti-counterfeiting element, is white. The optical anti-counterfeiting element is applied on a supporting body with a white surface, so that the anti-counterfeiting product has extremely strong visual characteristics and anti-counterfeiting performance.

According to another aspect of the present invention, there is provided a method for manufacturing an optical security element, where the optical security element is manufactured by using the method for manufacturing an optical security element, the method for manufacturing an optical security element includes: step S10: forming a microstructure layer 30 having a first region 31 and a second region 32 on the surface of the base layer 10, forming a first microstructure 311 on the first region 31, and forming a second microstructure 321 having a specific volume larger than that of the first microstructure 311 on the second region 32; step S20: forming a metal layer 40 on a surface of microstructured layer 30 remote from substrate layer 10; step S30: forming a protective layer 60 on the surface of the metal layer 40 away from the microstructure layer 30 to protect the first region 31; step S40: removing the metal layer 40 at the second region 32; step S50: an interference optically variable layer 50 is formed on the surface of the side remote from the substrate layer 10 to form an optical security element.

Step S10: forming an optical layer 20 having a first region 31 and a second region 32 on a surface of the base layer 10; and the specific volume of the second microstructure 321 is larger than that of the first microstructure 311, and the first microstructure 311 is a achromatic microstructure,

the substrate layer 10 may be at least partially transparent, may be a colored dielectric layer, may be a transparent dielectric film with a functional coating on the surface, or may be a multilayer film formed by compounding. The base layer 10 is generally formed of a film material having excellent physical and chemical resistance and high mechanical strength, and for example, a plastic film such as a polyethylene terephthalate PET film, a polyethylene naphthalate PEN film, or a polypropylene PP film may be used to form the base layer 10, and the base layer 10 is preferably formed of a PET material. The substrate layer 10 may include an adhesion enhancing layer thereon to enhance the adhesion of the substrate layer 10 to the optical layer 20. A release layer may also be included on the substrate layer 10 to effect separation of the final product substrate layer 10 from the optical layer 20.

The microstructure layer 30 may be formed by batch replication by ultraviolet casting, molding, nanoimprinting, or the like. For example, the microstructure layer 30 may be formed of a thermoplastic resin through a molding process, i.e., a thermoplastic resin pre-coated on the base layer 10 is softened and deformed by heat while passing through a high-temperature metal stencil, thereby forming a specific optical microstructure, and then is cooled and molded. The microstructure layer 30 may be formed by a radiation curing casting process in which a radiation curing resin is applied to the base layer 10, and the master is pressed against the base layer, and irradiated with radiation such as ultraviolet rays or electron beams to cure the material, and then removed to form the microstructure layer 30.

To achieve the need for subsequent removal, 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 The specific volume of the second microstructure is greater than 0.4um ³ /um ² And is less than 2um ³ /um ² 。

The morphology of the achromatic microstructures is generally random arrangement of protrusions and/or recesses of different depths and sizes, the lateral feature size is generally greater than 1um, less than 10um, and the depth feature size is generally greater than 0.1um, less than 5um. For example, the micro-mirrors with the lateral dimensions of 5-10um and the depths of 1-4um are randomly distributed.

The specific morphology of the second microstructure is set as desired. For example, five-pointed star with relief features as shown in fig. 1, and the cross-section may be a blazed grating structure having a width of 5-10um and a depth of 1-2 um.

Step S20: forming a metal layer 40 on a surface of microstructured layer 30 remote from substrate layer 10;

the effect of the metal layer 40 is such that the achromatic microstructure exhibits a higher whiteness. The material of the metal layer 40 is required to have high reflectivity characteristics and may be one or more of aluminum, silver, tin, and titanium. Aluminum is preferred because of its low cost and ease of reaction with acids or bases to be partially removed. In this embodiment, the metal layer 40 is selected to be aluminum. The thickness of the metal layer 40 is generally greater than 10nm and less than 80nm, preferably greater than 20nm and less than 50nm. Too thin a metal layer, insufficient brightness; too thick a metal layer 40 may have poor fastness with the optical microstructured layer and may increase cost.

The metal layer 40 may generally be formed on the optical microstructure layer by physical and/or chemical vapor deposition methods, including, for example, but not limited to, thermal evaporation, magnetron sputtering, MOCVD, and the like. Preferably, the metal layer 40 is formed on the optical microstructured layer in a uniform surface density and in a conformal coverage.

Step S30: forming a protective layer 60 on the surface of the metal layer 40 away from the microstructure layer 30 to protect the first region 31;

the amount of protective layer 60 is such that the minimum thickness on the first microstructure 311 is significantly greater than the minimum thickness on the second microstructure 321. The minimum thickness of the protective layer 60 at the first microstructure 311 is generally located at the very top of the second microstructure 321. Thus, the protection layer 60 protects the metal layer 40 of the first region 31 significantly more than the metal layer 40 of the second region 32. It is generally desirable that the coating amount of the protective layer 60 per unit area is greater than 0.1g/m ² And less than 0.6g/m ² . The lower the viscosity of the protective layer 60 before application, the better the leveling, and therefore the viscosity of the protective paste is generally less than 100cP, preferably less than 50cP. The composition of the protective layer 60 may be a varnish or ink containing polyester, polyurethane, acrylic resin, or a combination thereof as a main resin.

Step S40: removing the metal layer 40 at the second region 32;

the protection layer 60 protects the metal layer 40 of the first region 31 significantly more than the metal layer 40 of the second region 32. Thus, over time, the corrosive atmosphere will reach and corrode the metal layer 40 at the second region 32 through the weak points of the protective layer 60 of the second region 32; during this time, the protective layer 60 effectively protects the metal layer 40 of the first region 31. In this way a metal layer 40 is obtained which is precisely located in the first region 31. Since the metal layer 40 is aluminum in this embodiment, the corrosive atmosphere may be an acid or alkali solution. Typically, after the metal layer 40 on the second region 32 is etched, the protective layer 60 on the plating also floats. Sometimes, after the metal layer 40 on the second region 32 is etched, the protection layer 60 may partially or even entirely remain on the microstructure layer 30, which does not affect the implementation of the subsequent process.

Step S50: an interference optically variable layer 50 is formed on the surface of the side remote from the substrate layer 10 to form an optical security element.

In the present embodiment, the interference light variable layer 50 is generally composed of an absorption layer 51, a dielectric layer 52, and a reflection layer 53. Since the interference light variable layer 50 exhibits different color characteristics when viewed from the absorption layer 51 side, the interference light variable layer 50 is formed in the order of the absorption layer 51, the dielectric layer 52, and the reflection layer 53. The reflective layer 53 is generally a thicker metallic material with good reflectivity and exhibits opaque or substantially opaque characteristics when viewed in perspective; dielectric layer 52 is typically a completely transparent or substantially completely transparent compound material; the absorber layer 51 is typically a relatively thin metallic material that transmits light and exhibits a translucent characteristic. The reflective layer 53 may be composed of aluminum, silver, copper, tin, chromium, nickel, titanium, or an alloy thereof, and is preferably aluminum because aluminum is low in cost and is easily removed by an acid or alkali solution; dielectric layer 52 may be made of MgF ₂ 、SiO ₂ 、ZnS、TiN、TiO ₂ 、TiO、Ti ₂ O ₃ 、Ti ₃ O ₅ 、Ta ₂ O ₅ 、Nb ₂ O ₅ 、CeO ₂ 、Bi ₂ O ₃ 、Cr ₂ O ₃ 、Fe ₂ O ₃ 、HfO ₂ Or ZnO; the absorbing layer 51 may be made of nickel, chromium, aluminum, silver, copper, tin, titanium or an alloy thereof, preferably nickel, chromium. The thickness of the reflective layer 53 is generally selected to be 10nm to 80nm, preferably 20nm to 50nm. The thickness of the absorption layer 51 is typically 3-10nm. The thickness of the dielectric layer 52 is determined by the desired optically variable color characteristics, typically 200-600nm。

Thus, a semi-finished optical security element is obtained in which the first microstructure areas exhibit the optical characteristics of the metal layer 40 and the second areas 32 exhibit the optical characteristics of the second coating.

After step S50, other functional coatings 70, such as anti-aging glue, are applied to protect the optical plating and/or hot melt glue to adhere to other substrate layers 10.

Example two

The difference from the first embodiment is that the specific structure of the first region 31 is different.

As shown in fig. 3, the first region 31 includes a first sub-region 312 and a second sub-region 313, the first sub-region 312 is continuously provided around the outer periphery of the second region 32, and the first microstructure 311 in the first sub-region 312 is a achromatic microstructure; the second sub-region 313 is continuously provided around the outer periphery of the first sub-region 312, and the first microstructure 311 in the second sub-region 313 is a non-achromatic white microstructure.

The second sub-region 313 has rainbow holographic features and the second region 32 is a five-star region having relief features and having color changing features that vary with tilt angle. The color-changing regions are strictly coincident with the five-pointed star regions having relief features. The first sub-area 312 is disposed around the edges of the five-pointed star, and the line widths of the first sub-area 312 are exactly equal at each position. The lines of the first sub-region 312 may be very fine, e.g. less than 20um. If the optical anti-counterfeiting element is stuck on a white protected product, the five-pointed star is abnormal and striking, and the embossment sense and the color change effect are added, so that the product has excellent anti-counterfeiting performance. In addition, the rainbow holographic effect of the second sub-region 313 further increases the visual effect and the anti-counterfeit performance.

Of course, the second region 32 may be other shapes.

Optionally, the plurality of non-achromatic white microstructures are periodically arranged; the non-achromatic white microstructures may be arranged in a certain period, for example, in a matrix.

Of course, the plurality of non-achromatic white microstructures may be arranged in a non-periodic manner, that is, the plurality of non-achromatic white microstructures may be arranged randomly.

Optionally, the cross-sectional structure of the non-achromatic white microstructure along the extension direction is at least one of a flat structure, a sinusoidal structure, a rectangular grating structure, a trapezoidal grating structure, a blazed grating structure, and an arc-shaped grating structure.

Fig. 4 is a possible cross-sectional view of the exemplary optical security element of fig. 3 along X-X, the optical security element comprising a substrate layer 10, a microstructured layer 30, a metallic layer 40, a protective layer 60, an interference light altering layer 50, and other functional coatings 70. The base layer 10 and the microstructured layer 30 are typically composed of transparent materials. The microstructure layer 30 comprises a first region 31 and a second region 32, the specific volume of the second microstructure 321 being greater than the specific volume of the first microstructure 311. In this embodiment, the first region 31 comprises a first sub-region 312 comprising achromatic microstructures and a second sub-region 313 comprising rainbow holographic microstructures. The first region 31 is provided with a metal layer 40 and the second region 32 is provided with an interference light variable layer 50. The first sub-region 312 of the first region 31 exhibits a white color characteristic to the outside and the second sub-region 313 exhibits a rainbow hologram characteristic to the outside, as viewed from the viewing side of the optical security element toward the base layer 10, i.e., from below. The second region 32 externally presents the image formed by the second microstructure 321 and the color change feature as a function of tilt angle. The interference light variable layer 50 may be provided in a full-width arrangement but does not exhibit visual characteristics due to being obscured by the metal layer 40 in the first region 31. The metal layer 40 is adjacent to the protective layer 60. The protective layer 60 is a natural product of the manufacturing process and generally does not provide additional optical effects. Other functional coatings 70 may be provided as desired, such as, for example, as an adhesive layer to adhere to the host product being protected.

It will be apparent that the embodiments described above are merely some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, shall fall within the scope of the present invention.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments in accordance with the present application. As used herein, the singular is also intended to include the plural unless the context clearly indicates otherwise, and furthermore, it is to be understood that the terms "comprises" and/or "comprising" when used in this specification are taken to specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof.

It should be noted that the terms "first," "second," and the like in the description and claims of the present application and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that embodiments of the present application described herein may be implemented in sequences other than those illustrated or described herein.

The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An optical security element, comprising a substrate layer (10) and an optical layer (20), the optical layer (20) being arranged on one side of the substrate layer (10) and being connected to the substrate layer (10), the optical layer (20) comprising a microstructured layer (30), the microstructured layer (30) comprising:

-a first region (31), the first region (31) having a plurality of first microstructures (311);

-a second region (32), said second region (32) having a plurality of second microstructures (321), said first region (31) having a white color feature, as seen from a side of said optical security element, said second region (32) having an interference optical color change feature, a specific volume of said second microstructures (321) being larger than a specific volume of said first microstructures (311).

2. The optical security element of claim 1, wherein the optical layer (20) further comprises:

-a metal layer (40), said metal layer (40) being connected to a side of said first region (31) remote from said substrate layer (10);

an interference light variable layer (50), the interference light variable layer (50) being connected to at least a side of the second region (32) remote from the substrate layer (10).

3. The optical security element of claim 2, wherein the optical layer (20) further comprises a protective layer (60), the protective layer (60) being connected to a side of the metal layer (40) remote from the substrate layer (10).

4. An optical security element as claimed in claim 3, characterized in that the interference optically variable layer (50) is connected to the side of the protective layer (60) remote from the metal layer (40).

5. An optical security element according to claim 2, characterized in that the interference optically variable layer (50) comprises an absorbing layer (51), a dielectric layer (52) and a reflecting layer (53) arranged in sequence, the absorbing layer (51) being connected to at least the side of the second region (32) remote from the substrate layer (10).

6. The optical security element of claim 5 wherein,

the material of the absorption layer (51) comprises at least one of nickel, chromium, aluminum, silver, copper, tin and titanium; and/or

The material of the dielectric layer (52) comprises at least one of magnesium fluoride, silicon dioxide, zinc sulfide, titanium nitride, titanium dioxide, titanium monoxide, titanium oxide, tantalum pentoxide, niobium pentoxide, cerium oxide, bismuth trioxide, chromium trioxide, iron oxide, hafnium dioxide or zinc oxide; and/or

The material of the reflecting layer (53) comprises at least one of aluminum, silver, tin, nickel and titanium.

7. The optical security element of claim 2 wherein,

the metal layer (40) comprises at least one of aluminum, silver, tin, nickel, titanium; and/or

The thickness of the metal layer (40) is greater than 10nm and less than or equal to 80nm.

8. The optical security element of claim 1 wherein,

the specific volume of the first microstructure (311) is more than or equal to 0 and less than or equal to 0.5um ³ /um ² The method comprises the steps of carrying out a first treatment on the surface of the And/or

The specific volume of the second microstructure (321) is in the range of more than 0.4um ³ /um ² And is less than 2um ³ /um ² 。

9. An optical security element as claimed in any one of claims 1 to 8, wherein the first microstructures (311) are all achromatic microstructures.

10. The optical security element of claim 9 wherein at least two of the plurality of achromatic microstructures are different in size, at least two of the plurality of achromatic microstructures are different in height, and the achromatic microstructures are protrusions or grooves.

11. The optical security element of claim 9 wherein,

the length of the achromatic white microstructure is more than 1um and less than 10um; and/or

The depth of the achromatic white microstructure is more than 0.1um and less than 5um.

12. An optical security element as claimed in claim 9 wherein the achromatic microstructure is a micro-mirror,

the length of the micro-reflecting mirror is more than or equal to 5um and less than or equal to 10um; and/or

The depth of the micro-mirror is more than 1um and less than or equal to 4um.

13. The optical security element according to any one of claims 1 to 8, wherein the first region (31) comprises:

a first sub-region (312), the first sub-region (312) being arranged continuously around the outer periphery of the second region (32), the first microstructure (311) in the first sub-region (312) being a achromatic microstructure;

-a second sub-region (313), said second sub-region (313) being arranged consecutively around the periphery of said first sub-region (312), said first microstructure (311) within said second sub-region (313) being a non-achromatic white microstructure.

14. The optical security element of claim 13 wherein,

the plurality of non-achromatic white microstructures are arranged periodically; or alternatively

The plurality of non-achromatic white microstructures are arranged in a non-periodic manner.

15. An optical security element as defined in claim 13 wherein the cross-sectional structure of the non-achromatic white microstructure along the direction of elongation is: at least one of a flat structure, a sine structure, a rectangular grating structure, a trapezoid grating structure, a blazed grating structure and an arc grating structure.

16. The optical security element of any one of claims 1 to 8 wherein,

a plurality of the second microstructures (321) are arranged periodically; or alternatively

The second microstructures (321) are arranged in a non-periodic manner.

17. An optical security element according to any one of claims 1 to 8, characterized in that the second microstructure (321) has a cross-sectional structure in the direction of extension of: at least one of a flat structure, a sine structure, a rectangular grating structure, a trapezoid grating structure, a blazed grating structure and an arc grating structure.

18. A security product comprising an optical security element as claimed in any one of claims 1 to 17.

19. The security product of claim 18 further comprising a carrier, the optical security element being disposed on the carrier, at least a portion of a surface of the carrier carrying the optical security element being white.

20. A method of making an optical security element, wherein the optical security element of any one of claims 1 to 17 is made by the method of making an optical security element, the method of making an optical security element comprising:

step S10: forming a microstructure layer (30) having a first region (31) and a second region (32) on the surface of the base layer (10), forming a first microstructure (311) on the first region (31), and forming a second microstructure (321) having a specific volume larger than that of the first microstructure (311) on the second region (32); step S20: forming a metal layer (40) on a surface of the microstructure layer (30) remote from the base layer (10);

step S30: -forming a protective layer (60) protecting the first region (31) on a surface of the metal layer (40) remote from the microstructure layer (30);

step S40: -removing the metal layer (40) at the second region (32);

step S50: the optical anti-counterfeiting element is formed by forming an interference optically variable layer (50) on the surface of the side far away from the substrate layer (10).