US-20260124849-A1 - Optical Anti-Counterfeiting Element, Optical Anti-Counterfeiting Product and Manufacturing Method

US20260124849A1US 20260124849 A1US20260124849 A1US 20260124849A1US-20260124849-A1

Abstract

The disclosure provides an optical anti-counterfeiting element, an optical anti-counterfeiting product and a manufacturing method. The optical anti-counterfeiting element includes: a substrate; a micro-structure forming layer, wherein the micro-structure forming layer is arranged on a side surface of the substrate, the micro-structure forming layer has micro-structures, and a longitudinal section of each of the micro-structures has a preset shape; and a coating layer, wherein the coating layer is arranged on the micro-structure forming layer, the micro-structures are coated with the coating layer to form a coated micro-structure, and a height of each of the coated micro-structures continuously changes; wherein when shapes of the micro-structures have an abrupt-change, the coating layer has a demetallized region, and when a height of each of the micro-structures changes continuously, the coating layer has no demetallized region. The disclosure solves the problem in the related art that an optical effect actually generated by the optical anti-counterfeiting element has large deviation from an expected optical effect.

Inventors

Weiwei Zhang
Kai Sun
BAOLI ZHANG
Dong Yang

Assignees

ZHONGCHAO SPECIAL SECURITY TECHNOLOGY CO., LTD
CHINA BANKNOTE PRINTING AND MINTING CORP.

Dates

Publication Date: 20260507
Application Date: 20240105
Priority Date: 20230516

Claims (20)

1 . An optical anti-counterfeiting element, comprising: a substrate; a micro-structure forming layer, wherein the micro-structure forming layer is arranged on a side surface of the substrate, the micro-structure forming layer has micro-structures, and a longitudinal section of each of the micro-structures has a preset shape; and a coating layer, wherein the coating layer is arranged on the micro-structure forming layer, the micro-structures are coated with the coating layer to form coated micro-structures, and a height of each of the coated micro-structures continuously changes; wherein when shapes of the micro-structures have an abrupt-change, the coating layer has a demetallized region, and when a height of each of the micro-structures changes continuously, the coating layer has no demetallized region.
2 . The optical anti-counterfeiting element according to claim 1 , wherein the demetallized region is provided at a position where the abrupt change occurs in the micro-structures, such that the height of each of the coated micro-structures changes continuously, wherein the demetallized region is in a non-macro demetallized graphic-text form; the non-macro demetallized graphic-text refers to demetallized graphic-text which is not able to be observed directly by human eyes and is able to be observed only by using a microscope, and the non-macro demetallized graphic-text does not affect the anti-counterfeiting effect of the coating layer.
3 . The optical anti-counterfeiting element according to claim 2 , wherein the demetallized region has a feature width greater than or equal to 0.1 μm and less than or equal to 100 μm.
4 . The optical anti-counterfeiting element according to claim 2 , wherein a ratio of an area of the demetallized region to a total area of the optical anti-counterfeiting element is less than or equal to 0.5.
5 . The optical anti-counterfeiting element according to claim 2 , wherein when there are a plurality of demetallized regions, at least two demetallized regions among the plurality of demetallized regions are connected with each other.
6 . The optical anti-counterfeiting element according to claim 2 , wherein when there are a plurality of demetallized regions, at least two demetallized regions among the plurality of demetallized regions are not connected with each other.
7 . The optical anti-counterfeiting element according to claim 1 , wherein the preset shape comprises at least one of a sine shape, a wedge shape, symmetrical rectangular teeth, asymmetrical rectangular teeth, and a trapezoid shape.
8 . The optical anti-counterfeiting element according to claim 1 , wherein each of the micro-structures has a feature size of greater than or equal to 0.1 μm and less than or equal to 500 μm in a plane parallel to the substrate.
9 . The optical anti-counterfeiting element according to claim 8 , wherein each of the micro-structures has the feature size of greater than or equal to 0.2 μm and less than or equal to 100 μm in the plane parallel to the substrate.
10 . The optical anti-counterfeiting element according to claim 1 , wherein the coating layer provides a preset reflective feature or a preset transmissive feature.
11 . The optical anti-counterfeiting element according to claim 1 , wherein the coating layer is a single reflective layer or a single dielectric layer.
12 . The optical anti-counterfeiting element according to claim 1 , wherein the coating layer is a stack layer formed by stacking multiple layers of dielectric layers; or the coating layer is a stack layer formed by alternately stacking reflective layers and dielectric layers.
13 . The optical anti-counterfeiting element according to claim 1 , wherein the optical anti-counterfeiting element further comprises a protective layer, wherein the protective layer is arranged on the coating layer, and the protective layer is a transparent layer.
14 . The optical anti-counterfeiting element according to claim 13 , wherein a difference in refractive indexes between the protective layer and the micro-structure forming layer is less than 0.5.
15 . An optical anti-counterfeiting product, comprising the optical anti-counterfeit element according to claim 1 .
16 . A method for manufacturing an optical anti-counterfeiting element, wherein the method for manufacturing an optical anti-counterfeiting element is configured for manufacturing the optical anti-counterfeiting element according to claim 1 , wherein the method for manufacturing an optical anti-counterfeiting element comprises: forming a micro-structure forming layer having micro-structures on a substrate; forming a coating layer having a demetallized region on the micro-structure forming layer; and forming a protective layer on the coating layer.
17 . The optical anti-counterfeiting element according to claim 2 , wherein the preset shape comprises at least one of a sine shape, a wedge shape, symmetrical rectangular teeth, asymmetrical rectangular teeth, and a trapezoid shape.
18 . The optical anti-counterfeiting element according to claim 2 , wherein each of the micro-structures has a feature size of greater than or equal to 0.1 μm and less than or equal to 500 μm in a plane parallel to the substrate.
19 . The optical anti-counterfeiting element according to claim 2 , wherein the plating layer provides a preset reflective feature or a preset transmissive feature.
20 . The optical anti-counterfeiting element according to claim 2 , wherein the optical anti-counterfeiting element further comprises a protective layer, wherein the protective layer is arranged on the plating layer, and the protective layer is a transparent layer.

Description

TECHNICAL FIELD The disclosure claims priority to Patent Application No. 202310551025.X, filed to the China National Intellectual Property Administration on May 16, 2023 and entitled “Optical Anti-Counterfeiting Element, Optical Anti-Counterfeiting Product and Manufacturing Method”. The disclosure relates to the technical field of optical anti-counterfeiting devices, and in particular, to an optical anti-counterfeiting element, an optical anti-counterfeiting product and a manufacturing method. BACKGROUND An optical anti-counterfeiting product generally modulates incident light by using an optical micro-structure and a coating layer, to form a plurality of optical features, such as colors, dynamics, and stereo features, etc. These features are different from those of a generally fixed and planarized printing pattern. When an optical anti-counterfeiting element is tilted and rotated, a corresponding pattern may generate a color change, a dynamic feeling or a special feeling that the pattern is floating above/recessed into the plane where the pattern is located, thereby protecting the product. The optical micro-structure is typically a micro-nanostructure, and the structure may be a refractive element such as a micro-lens; may be a reflective element, such as a reflective surface; may also be a diffractive element, such as a holographic grating; or a surface plasmon structure of a smaller size capable of achieving interaction between light and electrons, such as a sub-wavelength grating. No matter which optical principle is based on, the features of the micro-structure are generally in the plane of the optical anti-counterfeiting element, and undulating surface morphologies of various shapes are obtained by means of micro-nano machining. For the other key element, i.e. the coating layer, generally, a layer of optical thin film is formed on the surface of the structure by means of vacuum physical vapor deposition or chemical vapor deposition. Generally, specific optical features may be obtained by using a single layer of metal material/dielectric material, or a stack of metal material and a stack of dielectric material, or a manner of metal materials/dielectric materials overlapping with each other. Under existing process conditions, the micro-structure is generally obtained by means of laser interference, laser direct writing or electron beam direct writing, and then mass production is performed by means of mold pressing, ultraviolet casting, etc., and the micro-structure is transferred to other substrates. However, there are two situations in which the optical features of an actual product deviate from original designs. When parameters of the micro-structure are changed, the height of each of the micro-structures abruptly changes, and the structure is deformed. For example, as for two reflective surfaces in close proximity to each other and having the same orientation, the position of the highest point of a first reflective surface in the plane of the optical element is theoretically the same as the position of the lowest point of a second reflective surface in the plane of the optical anti-counterfeiting element. However, in an actual manufacturing process, neither precision of a preparation manner (laser, electron beam) nor resolution of a material (photoresist) is able to form such a steep abrupt change, but a gradual change from the highest point to the lowest point is formed within a certain size range, for example, within a range of 0.5-1 μm. Such a gradient change forms another micro-structure which was not considered at the beginning of the design, which thus will generate interference to the design effect, thereby causing deviation of the optical features. In addition, the micro-structure replicates the resulting contraction and deformation. The original micro-structure may not be replicated 100% in the replication process, and deviations will be generated to some extent, especially at positions where the height of each of the micro-structures abruptly changes. Due to isomorphic coverage, the coating layer on these micro-structure change regions will also keep the described defect, and even amplifies deviations caused by the defect. Therefore, there is a need to weaken or avoid the occurrence of these problems in practical production, making actual optical features as consistent as possible with intended designs. SUMMARY Some embodiments of the disclosure provide an optical anti-counterfeiting element, an optical anti-counterfeiting product and a manufacturing method, so as to solve the problem in the related art that an optical effect actually generated by the optical anti-counterfeiting element has large deviation from an expected optical effect. In an embodiment of the disclosure, an optical anti-counterfeiting element is provided, including: a substrate; a micro-structure forming layer, wherein the micro-structure forming layer is arranged on a side surface of the substrate, the micro-structure f