WO2022227740A1

WO2022227740A1 - Optical anti-counterfeiting element and design method therefor, anti-counterfeiting product, and data carrier

Info

Publication number: WO2022227740A1
Application number: PCT/CN2022/073788
Authority: WO
Inventors: 孙凯; 朱军
Original assignee: 中钞特种防伪科技有限公司; 中国印钞造币总公司
Priority date: 2021-04-25
Filing date: 2022-01-25
Publication date: 2022-11-03
Also published as: CN115230364B; EP4331858A1; CN115230364A

Abstract

Provided are an optical anti-counterfeiting element and a design method therefor, an anti-counterfeiting product, and a data carrier. The optical anti-counterfeiting element (1) has a diffuse reflection region (2); the diffuse reflection region can reflect incident light into the range of at least a preset observation angle set Ωv; the diffuse reflection region comprises a plurality of reflection facets (3); the plurality of reflection facets comprise modified reflection facets that are globally or locally modified, and unmodified reflection facets; the modified reflection facets and the unmodified reflection facets have different reflection characteristics, wherein the modified reflection facets correspond to a pattern region (71, 81); and when the diffuse reflection region is irradiated by the incident light, the modified reflection facets are collectively presented as a pattern of a dynamic feature, and the unmodified reflection facets are collectively presented as a background (72, 82) of the dynamic feature. The optical anti-counterfeiting element is simple in manufacturing process, and can flexibly implement a dynamic feature such as color and/or light-dark contrast.

Description

Optical anti-counterfeiting element and design method thereof, anti-counterfeiting product, data carrier

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority of the Chinese patent application submitted to the China Patent Office on April 25, 2021, the application number is 202110449753.0, and the application name is "optical anti-counterfeiting element and its design method, anti-counterfeiting product, data carrier", and its entire content Incorporated herein by reference.

technical field

The present application relates to the technical field of anti-counterfeiting, in particular to an optical anti-counterfeiting element and a design method thereof, an anti-counterfeiting product, and a data carrier.

Background technique

In order to prevent counterfeiting by means of scanning and copying, optical anti-counterfeiting technology is widely used in various high-security or high-value-added products such as banknotes and financial instruments, and has achieved very good results.

At present, the eye-catching technology is the combination of the microstructure determined by the plate making and the optically variable layer, as disclosed in Chinese Patents CN 102712207 A and CN 107995894 A, by modulating the brightness distribution of the reflected light through the pre-designed micro-reflection surface, so as to realize Dynamic effect, and can superimpose interference coating to realize the combination of color change and dynamic effect. This often produces patterns, such as lines, rings, curves, or multiple motion effects of text, and can create a three-dimensional feel. However, in most cases, the color tone of the pattern and the background can only be the same, and the light-dark contrast relationship is basically single, so it is difficult to realize the dynamic characteristics of multiple colors or any light-dark relationship.

Demonstrations with three-dimensional depth effects can also be produced by Moiré magnification constructions based on microlenses and micropatterns, such as described in document WO 2005/052650 A2. Here, a periodic presentation composed of many small micropatterns is enlarged using a grid composed of microlenses with similar but not identical periods. In this way, it is possible to produce a stereoscopic effect that is clearly in front of or behind the actual surface, or to produce so-called orthogonal parallax motion. However, the disadvantage of this moiré magnification configuration is that it is complex to manufacture, requiring two imprinting steps for the microlenses and micropatterns, with precise alignment between the two steps.

Finally, as described for example in WO2014/108303A1, magnetically aligned reflective pigments are aligned with correspondingly shaped magnets, resulting in a bright (especially annular) dynamic effect that can include a certain depth effect. This effect is very bright and easy to see, but the magnetic ink required is expensive, and the variety and resolution of the effect is limited by the available magnets, making it difficult to adjust at will.

Therefore, there is a need to develop an optical anti-counterfeiting element with a simple manufacturing process and flexible realization of dynamic features of color and/or light-dark contrast.

Application content

The purpose of this application is to provide an optical anti-counterfeiting element and its design method, anti-counterfeiting product, and data carrier. The optical anti-counterfeiting element has a simple manufacturing process and can flexibly realize dynamic features such as color and/or light-dark contrast.

In order to achieve the above object, the present application provides an optical anti-counterfeiting element, which can exhibit dynamic features, and the dynamic features are pre-designed as a reproduction of a set of animation frames visible at a preset viewing angle set Ωv, and the animation frames include pattern areas and The background area that forms optical contrast with the pattern area; the optical anti-counterfeiting element has a diffuse reflection area, and the diffuse reflection area can reflect the incident light to at least the range of the preset viewing angle set Ωv; the diffuse reflection area includes a plurality of reflective surface elements, a plurality of The reflective surface element includes the modified reflective surface element and the unmodified reflective surface element that are modified in whole or in part. The modified reflective surface element and the unmodified reflective surface element have different reflection characteristics. The surface element corresponds to the pattern area; when the diffuse reflection area is illuminated by the incident light, the modified reflection surface elements together appear as a pattern with dynamic features, and the unmodified reflection surface elements together appear as a dynamic feature background.

Optionally, the angles of the reflection surface elements in the plurality of reflection surface elements are randomly selected in the preset angle set Ωs, wherein the elements in the preset observation angle set Ωv, the elements in the preset angle set Ωs, and the angle of the incident light pass through the set. associated with the law of reflection.

Optionally, the angle of the reflection surface element in the plurality of reflection surface elements is determined by the inclination angle and the azimuth angle of the reflection surface element, and the inclination angle is preferably 0° to 20° and/or the azimuth angle is preferably 0° to 360°.

Optionally, the angle of the reflection surface element in the multiple reflection surface elements is obtained by randomly selecting elements in the preset angle set Ωs with equal probability; and/or the angle of the reflection surface element in the multiple reflection surface elements is obtained by using pseudo-random The number generation program is randomly selected from the preset angle set Ωs.

Optionally, the lateral dimension of the reflection surface element in the plurality of reflection surface elements is 3 μm to 100 μm, preferably 10 μm to 30 μm.

Optionally, the reflection surface element among the plurality of reflection surface elements is a plane or a curved surface.

Optionally, at least a part of the unmodified reflective surface element is smooth or has a secondary structure; and/or at least a part of the diffuse reflection area is coated or coated.

Optionally, the modified reflective surface element is globally or partially modified in one or more of the following ways: adding secondary structures to the modified reflective surface element; smoothing the modified reflective surface element ; flatten the modified reflection surface; set the modified reflection surface to be convex or concave compared to the unmodified reflection surface; adjust the angle of the modified reflection surface so that the incident light be reflected to a range beyond the preset viewing angle set Ωv; or the thickness of the coating or coating of the modified reflective surface element is adjusted to be different from that of the unmodified reflective surface element.

Optionally, in the case that the modified reflective surface element is modified in two or more ways among multiple ways, the two or more ways are combined in parallel and/or in series. exist.

Optionally, the lateral feature size of the secondary structure is 0.2 μm to 5 μm.

Optionally, the width of the modified region of the modified reflective surface element is 0.5 μm to 30 μm, preferably 2 μm to 10 μm.

Optionally, the different reflection characteristics refer to one or a combination of different reflection colors, different reflection brightness, or different reflection textures when the modified reflection surface element and the unmodified reflection surface element are irradiated by incident light.

Correspondingly, the present application also provides a design method for an optical anti-counterfeiting element, the design method comprising: designing a dynamic feature, where the dynamic feature is the reproduction of a group of animation frames visible at a preset viewing angle set Ωv, and the animation frames include patterns. area and a background area that forms optical contrast with the pattern area; a diffuse reflection area designed for use in an optical anti-counterfeiting element, the diffuse reflection area is capable of reflecting incident light to at least a range of a preset viewing angle set Ωv, wherein the diffuse reflection area includes a plurality of Reflection surface element; based on the observation angle of each animation frame of a group of animation frames, the reflection surface element corresponding to the pattern area of each animation frame is modified to form a modified reflection surface element, so that the modified reflection surface element and Unmodified reflective surface elements have different reflection characteristics. When the diffuse reflection area is illuminated by incident light, the modified reflective surface elements collectively present a pattern with dynamic characteristics, and the unmodified reflective surface elements collectively present a dynamic characteristic pattern. background.

Optionally, the angles of the reflection surface elements in the multiple reflection surface elements are randomly selected in the preset angle set Ωs, including: obtaining the reflections in the multiple reflection surface elements by randomly selecting elements in the preset angle set Ωs with equal probability. the angle of the surfel; and/or by using a pseudo-random number generation program to randomly select the angle of the reflection surfel among the plurality of reflective surfels from the preset angle set Ωs.

Optionally, the design method further includes: designing at least a part of the unmodified reflective surface element to be smooth or with a secondary structure; and/or designing at least a part of the diffuse reflection area to be coated or coated .

Optionally, modifying the reflection surface element corresponding to the pattern area of each animation frame to form a modified reflection surface element includes: pixelizing each animation frame in a group of animation frames; determining each animation frame The first azimuth angle and the first pitch angle of the frame, the first azimuth angle and the first pitch angle are determined according to the observation angle of the animation frame; the second azimuth angle and the second pitch angle of each reflection surface element in the diffuse reflection area are determined; For each animation frame in a set of animation frames, the following steps are performed: at the positions of the diffuse reflection area corresponding to the pixels of the pattern area in the animation frame, look for a match with the first azimuth angle and the first pitch angle of the animation frame The reflection surface elements corresponding to the second azimuth angle and the second elevation angle of The reflection surface element corresponding to the area is modified.

Optionally, look for a second azimuth angle and a second pitch angle corresponding to the first azimuth angle and the first pitch angle of the animation frame at the position corresponding to the pixel of the pattern area in the animation frame. The reflection surface element includes: within the preset distance range of the position corresponding to the pixel of the pattern area in the animation frame, in the diffuse reflection area, searching for the angle difference between the first azimuth angle and the first preset angle difference range within the range of the first preset angle difference The second azimuth angle within the second azimuth angle and the reflective surface element corresponding to the second pitch angle whose angle difference between half of the first pitch angle is within the second preset angle difference range.

Optionally, the preset distance range refers to that the distance from the pixel position of the pattern area in the animation frame is less than 100 μm, preferably less than 50 μm; and/or the first preset angle difference range refers to the distance from the first azimuth angle. The angle difference between them is less than 3°, preferably less than 0.5°; and/or the second preset angle difference range means that the angle difference from the first pitch angle is less than 3°, preferably less than 0.5°.

Optionally, modifying the reflective surface element corresponding to the pattern area of each animation frame to form a modified reflective surface element includes: adding a secondary structure to the modified reflective surface element; adding a secondary structure to the modified reflective surface element; Smooth; flatten the modified reflective surface; set the modified reflective surface to be convex or concave compared to the unmodified reflective surface; adjust the angle of the modified reflective surface, The incident light is reflected to a range beyond the preset observation angle set Ωv; or the thickness of the coating or coating of the modified reflective surface element is adjusted to be different from that of the unmodified reflective surface element.

Optionally, the dynamic feature is one or a combination of translation, rotation, scaling, deformation, looming, and yin-yang conversion; and/or the optical contrast is one of different colors, different brightness, and different textures visible to the human eye or its combination.

Correspondingly, the present application also provides an anti-counterfeiting product using the above-mentioned optical anti-counterfeiting element.

Correspondingly, the present application also provides a data carrier having the above-mentioned optical anti-counterfeiting element or the above-mentioned anti-counterfeiting product.

The optical anti-counterfeiting element provided by the embodiment of the present application has a simple manufacturing process and can flexibly realize dynamic features such as color and/or light-dark contrast. In addition, various multi-color dynamic features can be displayed macroscopically, and there is no directly identifiable microscopic feature. Arrangement rules to enhance the difficulty of counterfeiting in multiple dimensions such as microstructure design and manufacturing process.

Other features and advantages of the embodiments of the present application will be described in detail in the detailed description section that follows.

Description of drawings

The accompanying drawings are used to provide further understanding of the embodiments of the present application, and constitute a part of the specification, and are used to explain the embodiments of the present application together with the following specific embodiments, but do not constitute limitations to the embodiments of the present application. In the drawings, for the sake of clarity, the illustrations are not drawn to scale. In the attached image:

1 is a schematic diagram of the diffuse reflection effect of the diffuse reflection area of the optical anti-counterfeiting element on incident light;

Fig. 2 is an example diagram of a design method of the pitch angle and the azimuth angle of a reflection surface element;

Fig. 3 is another example diagram of the design method of the pitch angle and the azimuth angle of the reflection plane;

Fig. 4 is an embodiment of determining the reflection surface element to be modified according to the animation frame;

FIG. 5 is another embodiment of determining the reflection surface element to be modified according to the animation frame;

6 is a schematic diagram of a partial or overall modification method of a modified reflection surface element;

Figure 7 is a schematic diagram of the use of the optical anti-counterfeiting element on a banknote.

Detailed ways

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

On the one hand, the embodiments of the present application provide an optical anti-counterfeiting element. The optical anti-counterfeiting element can present dynamic features. The dynamic features are pre-designed as the reproduction of a set of animation frames visible at a preset viewing angle set Ωv, and the animation frames include a pattern area and a pattern area. The background area that forms the optical contrast; the optical anti-counterfeiting element has a diffuse reflection area, and the diffuse reflection area can reflect the incident light to at least the range of the preset observation angle set Ωv; the diffuse reflection area includes a plurality of reflection surface elements, and a plurality of reflection surface elements It includes the modified reflection surface element and the unmodified reflection surface element that are modified in whole or in part. The modified reflection surface element and the unmodified reflection surface element have different reflection characteristics. The pattern area corresponds; when the diffuse reflection area is illuminated by incident light, the modified reflective surface elements together appear as a dynamic feature pattern, and the unmodified reflective surface elements together appear as a dynamic feature background, that is, the modified reflection surface. The surface elements together reproduce the dynamic characteristic pattern, and the unmodified reflective surface elements jointly reproduce the dynamic characteristic background.

Different reflection characteristics refer to one or a combination of the modified reflection surface element and the unmodified reflection surface element having different reflection colors, different reflection brightness, or different reflection textures when the incident light is irradiated.

When the diffuse reflection area is irradiated by incident light, the animation frame can be observed at the observation angle corresponding to each animation frame, wherein the pattern of the observed animation frame is presented by the modified reflection surface element, and it is observed that The background of the animation frame is rendered by the undecorated reflective surfel.

In the embodiment of the present application, "a group of animation frames visible in the preset observation angle set Ωv" refers to a one-to-one correspondence between observation angles and animation frames, and one observation angle corresponds to one animation frame.

The dynamic features in the embodiments of the present application essentially refer to dynamic features that appear when the observation angle is changed. In principle, the viewing angle can be the angle of one or more of the three elements, the light source (ie the incident light), the optical security element and the observer. For example, under the condition that the illumination light source and the position of the human eye remain unchanged, hold the optical anti-counterfeiting element or the article with the optical anti-counterfeiting element in the hand, and shake the optical anti-counterfeiting element back and forth or left and right, that is, change the angle of the optical anti-counterfeiting element, You can see the dynamic characteristics of the design. In order to simplify the description in the present application, the observation direction is defined by the connecting line between the observer's eyes and the observed point, thereby defining the observation angle. It should be noted that this definition does not substantially affect or limit any related content of the embodiments of the present application. The observation angle is a three-dimensional space parameter, so it needs to be decomposed into at least two angles for accurate description. For example, the pitch angle and the azimuth angle can be used to describe together, or the angle between the three coordinate axes of the observation direction x, y, and z can be used to describe together. In the xyz coordinates defined in the embodiments of the present application, the xy plane is the plane where the optical anti-counterfeiting element is located, the x-axis can be the longitudinal direction of the optical anti-counterfeiting element, the y-axis can be the lateral direction of the optical anti-counterfeiting element, and the z-axis can be the same as the optical anti-counterfeiting element. The vertical axis of the element.

The pattern of the animation frame can be designed as letters, numbers, characters, symbols or geometric shapes (especially circles, ovals, triangles, rectangles, hexagons or stars, etc.). The above dynamic features generally refer to any one of any translation, rotation, scaling, deformation, looming, yin-yang conversion, etc. of the design pattern directly visible to the human eye presented by the optical anti-counterfeiting element, and can also be any combination of these dynamic features. . The translation can be designed to design the pattern to translate in a specific direction, or it can be designed to translate in multiple directions, and the translation direction is associated with the observation direction. A common combination feature is that when the position of the design animation frame pattern changes, its shape also changes, for example, a circle turns into a square. The dynamic feature can have the orthogonal parallax motion behavior of the pattern, that is, the motion direction of the pattern is always perpendicular to the change of the observation direction, which further attracts the observer's attention through the counter-intuitive phenomenon. The motion of the animation frame pattern can create a three-dimensional effect that floats above or below the plane of the element through the principle of binocular horizontal parallax. The pattern may also include multiple sub-patterns exhibiting the same or different motion behaviors and/or the same or different fly heights or depths. In particular, the pattern may comprise at least a first curve and a second curve which appear as a first or a second curve located at the center of the first or second area respectively when viewed from the first or second viewing direction, respectively. target curve. When the optical security element is tilted, the two curves preferably move in different (preferably opposite) directions, resulting in a particularly dynamic appearance. It will be appreciated that, in the same way, the pattern of the optical security element may also comprise more than two curves which may move in the same or different directions when the optical security element is tilted. For example, a curve in the form of an alphanumeric string may alternately exhibit different motion behaviors, such as alternately floating above or below the plane of the flat pattern area, and moving according to its floating height when tilted. For the specific principles of various dynamic features, please refer to the existing patent texts CN 102712207 A, CN 107995894 A, WO 2005/052650 A2, etc. In the embodiments of the present application, the terms "pattern" and "pattern area" can be replaced with each other.

Dynamic features can be represented by a set of pictures generated by computer software, such as mathematical calculation software, pattern processing software, etc., during specific design. For example, using a bitmap in the format of bmp, the design patterns of different colors and the common background of the patterns are reflected through the gray value of 0-255. Each picture corresponds to the visual information presented to the human eye under a specific viewing angle, which is called a frame animation of the designed dynamic feature.

The preset observation angle set Ωv refers to all the preset dynamic features that can be seen when the observation angle of the human eye changes within the set. Optical anti-counterfeiting elements may reflect illuminating light out of the collection, but these reflections may be unrelated to the designed animated feature, or may provide a darker or darker visual information for the dynamic feature. The preset observation angle set Ωv can be described by the azimuth angle and the elevation angle. For example, the azimuth angle can be designed to be 0°-360°, and the elevation angle can be 0°-35° or 10°-50°, etc. Dynamic features can be seen in the area where the eye is located in the cone. The setting of the angle parameter depends on the purpose of the designer, the lighting environment possessed by the observer, the viewing habits, and so on.

The reflection surface element of the diffuse reflection area can be a flat plane, and each reflection surface element is characterized in that it forms a certain inclination angle with respect to the plane where the pattern area of the dynamic feature is located, and has a certain rotation angle with respect to the x-axis direction. Elevation and azimuth angles can be used to determine the orientation of the reflection bin (which may also be referred to as the angle of the reflection bin). Of course, other parameters can also be used to determine the orientation of the surface element, especially parameters that are orthogonal to each other, such as two orthogonal components of the direction of the reflection surface element. Optionally, the reflection surface element of the diffuse reflection area may specifically be a curved surface. Mathematically, a surface can continue to be decomposed into a number of surface elements that are closer to a plane and have a smaller area, and the surface has no essential difference from a flat plane in specific design. In order to generate sufficiently fine patterns and continuously changing dynamic features, the size of the reflective surface element is preferably smaller than the recognition ability of the human eye. The recognition ability is usually about 100 μm at the photopic distance, and the resolution ability is improved at a shorter distance. Therefore, the size of the surface element should not be larger than 100 μm. On the other hand, if the surface element is too small, the light will be diffracted significantly, which will affect the color stability of dynamic features. The reflective surface element with a lateral size of 3 μm to 100 μm can generate sufficiently fine features without producing obvious diffraction iridescence, and the lateral size can be further preferably 10 μm to 30 μm. The projection of the reflection surface element on the plane of the dynamic pattern is usually selected as a rectangle, and it can also be any figure that is conducive to covering the plane, such as a triangle, a hexagon, or an irregular shape.

In the embodiment of the present application, the unmodified reflective surface element may be smooth or with a secondary structure. It can be understood that there may also be unmodified parts in the modified reflective surface element, and the unmodified parts may also be smooth or have secondary structures. In some optional embodiments, the diffusely reflective region may be provided with a coating or coating in at least a portion of the region.

The main function of the reflection surface elements constituting the diffuse reflection area is to generate uniform reflected light at least at the preset observation angle set Ωv, which is similar to the visual impression of diffuse reflection produced by general office paper. To achieve this purpose, the orientation of the reflection surface element is randomly changed or selected within the preset angle set Ωs, especially by random selection or pseudo-random selection (ie, it can be randomly selected within the preset angle set Ωs). Pseudo-random numbers are strings of numbers that appear random but are calculated by a deterministic algorithm, so they are not truly random numbers in the strict sense. However, pseudorandom numbers are widely used because the statistical properties of pseudorandom selection (such as equal probability of individual numbers or statistical independence of consecutive numbers) are usually sufficient for practical purposes, and unlike true random numbers, pseudorandom numbers are Random numbers are easily generated by computers.

Specifically, the random change of the orientation of the reflection surface element within the preset angle set Ωs can be achieved jointly by random change or selection of the elevation angle and random change or selection of the azimuth angle. The elements in the preset observation angle set Ωv, the elements in the preset angle set Ωs, and the angle ωi of the incident light are related by the law of collective reflection. The selection of the preset angle set Ωs must uniformly reflect the incident light to at least the preset observation angle set Ωv, so Ωs must cover a minimum set jointly determined by the incident light angles ωi and Ωv. Equivalently, the reflection area composed of multiple reflection surface elements reflects the incident light to the angle set Ωr, and Ωr covers the preset observation angle set Ωv, that is, Ωv is a subset or proper subset of Ωr. Preferably, Ωs is designed to be the smallest set jointly determined by the incident light angles ωi and Ωv, that is, Ωv is the same as Ωr. For example, when the incident light is normal incident on the surface of the optical anti-counterfeiting element, that is, the optical anti-counterfeiting element is in the xy plane, and the incident light is along the z direction, according to the law of geometric reflection, the azimuth angle of the element of Ωs is the same as the azimuth angle of the element of Ωv, while its The pitch angle of the element is half the pitch angle of the element of Ωv.

In order to realize the changing characteristics, it is necessary to modify the diffuse reflection area according to each pixel point of each animation frame, thereby changing the uniform reflected light distribution in the preset observation angle set Ωv. The size of the diffuse reflection area should be larger than the size of the area occupied by all animation frames, so that each animation frame can correspond to the diffuse reflection area without scaling, so that each pixel in the pattern area of the animation frame can Find the corresponding position point in the diffuse reflection area, the position point will be decorated.

According to the position Pv of the pattern area contained in a certain animation frame and its observed angle ωv, find the position Ps and angle ωs of the reflection surface to be modified. For example, you can find the reflection surface to be modified per pixel. position and angle. In principle, Pv and Ps should be in the same position, and ωv, ωs and the incident light angle ωi should satisfy the reflection law of geometric optics, that is, the normals of the incident light, the reflected light, and the reflecting surface are in the same plane, and The angle of incidence is equal to the angle of reflection. Here, ωs=f(ωv, ωi) is used to indicate that there is a quantitative relationship between the three, and the specific calculation formulas can be found in general optics textbooks, such as Born's "Principles of Optics: Electromagnetic Theory of Light Propagation, Interference and Diffraction" . In the actual design, since the angle of the reflection surface element is randomly selected in the preset angle set Ωs, when Pv=Ps, the angle ωs of the reflection surface element at this position may not exactly satisfy the geometric reflection law with ωv and ωi. Therefore, the reflection surface element to be modified can be found in a certain position range and a certain angle range, namely:

Ps∈(Pv-ΔP,Pv+ΔP)

ωs∈(f(ωv,ωi)-Δω,f(ωv,ωi)+Δω)

Among them, the position deviation ΔP and the angle deviation Δω are selected according to the size of the reflection surface element, the resolution of the angle and size of the human eye, and the designed dynamic characteristics. The principle is that at least one reflection surface element to be modified can be found, and at the same time There is no human eye distinguishable difference from the design pattern. Generally, the positional deviation ΔP is less than 100 μm, preferably less than 50 μm. The angular deviation Δω is defined as the angle between the normal direction of the modified reflective surface element and the normal direction of the reflective surface element corresponding to the preset viewing angle of the pattern. The angular deviation Δω should be less than 3°, preferably less than 0.5°.

Generally, let the elevation angles of the two reflection planes be θ ₁ and θ ₂ respectively, and the azimuth angles are respectively

The angle between the normals of the two reflecting surface elements can be calculated by the following formula:

When executed, each animation frame can be pixelated. Optionally, only the pattern area of each animation frame can be pixelated. The essence of pixelation is to divide the animation frame into, for example, N×M small areas, and the area occupied by each small area can be very small, for example. For example, the width of each small area in the embodiments of the present application may be 0.5 μm to 10 μm, preferably 2 μm to 4 μm, and correspondingly, the length of each small area may be 0.5 μm to 10 μm, preferably 2 μm to 4 μm. Finding the reflective surface to be modified is to find the reflective surface corresponding to the pixels of the pattern area.

Further, the first azimuth angle and the first pitch angle of each animation frame can be determined, and each animation frame corresponds to a specific observation angle, so the first azimuth angle and the first pitch angle can be determined according to the observation angle of the animation frame. . In the embodiment of the present application, the observation angle is a direction vector in a rectangular coordinate system. The angle between the direction vector and the xy plane is defined as the pitch angle (which can also be said to be the complementary angle to the z-axis). The direction vector is projected onto the xy plane to form a projection vector, and the angle between the projection vector and the x-axis is defined as the azimuth angle.

Further, the second azimuth angle and the second elevation angle of each reflection surface element of the diffuse reflection area may be determined. Each element in the preset angle set Ωs may be composed of an azimuth angle and an elevation angle, and therefore, the second azimuth angle and the second elevation angle of each reflection surface element may be stored in advance. Therefore, the second azimuth angle and the second elevation angle of each reflection surface element of the diffuse reflection area can be obtained from the database.

For each animation frame in a set of animation frames, the following steps may be performed: finding a first azimuth angle and a first pitch angle of the animation frame at a position of the diffuse reflection area corresponding to a pixel of the pattern area in the animation frame The reflection surface elements corresponding to the matching second azimuth angle and the second pitch angle are determined, so that the reflection surface element corresponding to the pattern region of the animation frame is determined in the diffuse reflection area. For example, a group of animation frames can be vertically projected on the diffuse reflection area in the same proportion, so that the position on the diffuse reflection surface corresponding to each pixel in each animation frame can be determined. Finding the reflection surface element corresponding to the second azimuth angle and the second elevation angle that match the first azimuth angle and the first elevation angle of the animation frame may include: in the diffuse reflection area corresponding to the pixels of the pattern area in the animation frame Within the preset distance range of the position, find the second azimuth angle whose angle difference from the first azimuth angle is within the range of the first preset angle difference, and the angle difference between the first pitch angle and half of the first pitch angle is The reflection surface element corresponding to the second pitch angle within the second preset angle difference range. Alternatively, in the case of small pitch angles, the difference in azimuth angle becomes unimportant. Therefore, in the case where the pitch angle is relatively small, the azimuth angle may not be considered, and only within the preset distance range, the angular difference between the first pitch angle and one-half of the first pitch angle can be found to be within the second preset angle difference range. The reflection surface element corresponding to the second pitch angle of . Optionally, when the pitch angle is below about 2°, it can be considered that the difference in orientation caused by the difference in azimuth angle is not obvious, and the azimuth angle can be ignored. The preset distance range means that the distance between the positions of the diffuse reflection area corresponding to the pixels of the pattern area in the animation frame is less than 100 μm, preferably less than 50 μm. The first preset angle difference range means that the angle difference from the first azimuth angle is less than 3°, preferably less than 0.5°. The second preset angle difference range means that the angle difference from half of the first pitch angle is less than 3°, preferably less than 0.5°. For a pixel in the pattern area, one or more qualified reflection surface elements may be found in the diffuse reflection area, and the one or more qualified reflection surface elements can be modified. After finding reflective surfels matching each pixel of the pattern area of the animation frame in the diffuse reflection area, these matched reflective surfels form reflective surfels corresponding to the pattern area of the animation frame. The modified reflection surface element can be formed by modifying the reflection surface element corresponding to the pattern region of each animation frame formed in the diffuse reflection region.

The modification of the reflection surface element can add a secondary structure to the modified reflection surface element. The feature size of the secondary structure is significantly smaller than that of the reflection surface element, so it can be spread on the surface of the reflection surface element along the direction of the reflection surface element. . The lateral feature size of the secondary structure is 0.2 μm to 5 μm, which can produce diffraction or absorption of visible light. The absorption can be based on the principle of surface plasmon resonance absorption, and the sub-wavelength scale grating structure absorbs the incident light of a specific frequency set, thereby changing the color of the reflected light while maintaining the original reflection direction. Usually, when the depth of the subwavelength structure is relatively deep, such as 300nm to 700nm, effective absorption can be generated in a wider frequency set, thereby significantly reducing the brightness of the reflected light in this direction, that is, the subwavelength structure becomes optical absorption or optical absorption. black structure.

The modified reflective surface element can have a secondary structure as a whole before modification, which can generate a uniform reflected light distribution within the preset observation angle set Ωv, and provide specific color or brightness characteristics at the same time. Therefore, the modification of the reflective surface element can smooth the part or the whole of the modified reflective surface element. For example, the secondary structure of the modified reflective surface element is removed, so that it can produce specular reflection with higher reflectivity for the entire visible light band. Optionally, at least a portion of the unmodified reflective facet may be provided to be smooth or with secondary structures.

The modification of the reflective surface element can be to flatten the modified reflective surface element, so that the modified reflective surface element can only reflect the incident light to a specific direction. At other viewing angles, the modified area provides little or no reflected light, resulting in a darker or darker visual perception than other areas.

The modification to the reflective surface element may be to adjust the angle of the modified reflective surface element, so that the modified reflective surface element can reflect all the light rays incident on the modified reflective surface element to a direction exceeding the preset observation angle set Ωv. Generally, the pitch angle of the reflection surface element is increased and exceeds a minimum set jointly determined by the incident light directions ωi and Ωv, and the incident light can be reflected to exceed the set determined by Ωv. The modified reflective facet provides little or no reflected light, resulting in a darker or darker visual perception than other areas.

To produce a pattern of sufficient contrast, the surface on which the modified reflective facet is located or the surface opposite the surface on which the modified reflective facet is located (eg, an unmodified reflective facet) may have a coating or coating. This includes reflection enhancing coatings (especially metallization layers), reflection enhancing coatings, reflective ink layers, absorbing ink layers, high refractive index material coatings, high refractive index material coatings. The reflection-enhancing coating, coating or reflective ink layer preferably has a color-shifting effect, ie a hue change of the color at different viewing angles, for example using a Fabry-Perot interference structure. Alternatively, the reflective areas and reflective facets can also be imprinted in the reflective ink layer or the absorbing ink layer.

The modification of the reflective surface element can be to form a convex or concave on the modified reflective surface element compared with the surrounding unmodified area; or the modification of the reflective surface element can be the coating or coating thickness of the modified reflective surface element. different from undecorated regions. For example, a reflective coating, coating, or ink on the modified reflective surface and no reflective coating, coating, or ink on the unmodified reflective surface; or no reflective coating on the modified reflective surface , coating or ink, while having a reflective coating, coating or ink on the unmodified reflective surface element.

The modification to the reflection surface element can be used in a serial manner of the above-mentioned multiple modification methods. For example, a lower recess is formed in the modified reflective surface element than the unmodified reflective surface element, and then a secondary structure is added in the recess, and finally the reflective coating in the secondary structure area is removed (that is, the same as the unmodified reflective surface). The reflective coating of the reflective surface element has different thickness); or, the modified reflective surface element is formed with a lower depression than the unmodified reflective surface element, and the color ink is filled in the depression, and its thickness is significantly larger than that of the unmodified reflective surface element. The thickness of the ink for the reflective bin. The modification to the reflection surface element can be used in parallel with multiple modification methods. For example, a flat concave is formed in a part of the modified reflection surface element, and a secondary structure is added along the direction of the reflection surface element in another part of the modified reflection surface element. The modification to the reflection surface element can be used in combination of the serial combination method and the parallel combination method of the above decoration methods.

The modified region can exist locally or in the entirety of the reflective surface being modified. For an ideal planar reflective bin, the trim area would be equal to the reflective bin. For curved reflective surface elements, the modified area will exist locally on the reflective surface element. In the embodiments of the present application, according to the visibility of the generated pattern, the width of the modified region is 0.5 μm to 20 μm, preferably 2 μm to 10 μm. The modified reflection surface element has one or a combination of different reflection color, different reflection brightness, and different reflection texture than the unmodified reflection surface element. Alternatively, the modified region may have one or a combination of different reflective colors, different reflective brightness, and different reflective textures than the unmodified regions.

Within the preset observation angle set Ωv of the optical anti-counterfeiting element, the modified reflective surface elements are collectively presented as a pattern of an animation frame, and the unmodified reflective surface elements are collectively presented as a background of the animation frame. The pattern area has a different optical contrast than the background area, which can be one or a combination of different colors, different brightness, and different textures visible to the human eye.

The embodiment of the present application also provides a design method for an optical anti-counterfeiting element, the design method includes: designing a dynamic feature, where the dynamic feature is the reproduction of a group of animation frames visible at a preset viewing angle set Ωv, and the animation frames include a pattern area and a background area that forms an optical contrast with the pattern area; a diffusely reflective area designed for use in an optical anti-counterfeiting element, the diffusely reflective area is capable of reflecting incident light to at least a range of a preset set of viewing angles Ωv, wherein the diffusely reflective area includes a plurality of reflections Surface element; based on the observation angle of each animation frame of a group of animation frames, the reflection surface element corresponding to the pattern area of each animation frame is modified to form a modified reflection surface element, so that the modified reflection surface element is different from the unmodified reflection surface element. The modified reflective surface elements have different reflection characteristics. When the diffuse reflection area is illuminated by incident light, the modified reflective surface elements collectively present a dynamic feature pattern, and the unmodified reflective surface elements collectively present a dynamic feature background. .

Dynamic features can be represented by a set of pictures generated by computer software, such as mathematical calculation software, pattern processing software, etc., during specific design. For example, using a bitmap in the format of bmp, the design patterns of different colors and the common background of the patterns are reflected through the gray value of 0-255. Each picture corresponds to the visual information presented to the human eye under a specific viewing angle, which is called a frame animation of the designed dynamic feature. For the specific working principle and benefits of the design method for the optical anti-counterfeiting element according to the embodiment of the present application, reference may be made to the description of the optical anti-counterfeiting element in the embodiment of the present application, which will not be repeated here.

Correspondingly, the embodiment of the present application further provides an anti-counterfeiting product using the optical anti-counterfeiting element of any embodiment of the present application. For example, the anti-counterfeiting product can be in the form of anti-counterfeiting thread, anti-counterfeiting strip, and anti-counterfeiting label. The embodiments of the present application further provide a data carrier having the anti-counterfeiting element according to any embodiment of the present application or the anti-counterfeiting product according to any embodiment of the present application, and the anti-counterfeiting element or the anti-counterfeiting product can be arranged in the opaque area of the data carrier and in the data carrier. in or above the transparent window area or through opening. The data carrier can in particular be a document of value, such as bank notes (especially paper bank notes, polymer bank notes or film composite bank notes), stocks, warrants, certificates, tickets, checks, high-value tickets, but also Is an identification card, such as a credit card, bank card, cash card, authorization card, personal identification card, or the personal information page of a passport, etc.

The optical anti-counterfeiting element provided in real time by the present application and the manufacturing method thereof will be further described below with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of the diffuse reflection effect of the diffuse reflection area 2 of the optical anti-counterfeiting element on the incident light 4 . The plane where the optical anti-counterfeiting element 1 is located is defined as the xy plane, and the diffuse reflection area 2 is composed of a plurality of reflection surface elements 3 . In FIG. 1 , the optical anti-counterfeiting element 1 has a base material 6 , and the diffuse reflection area 2 is located on one side of the base material 6 . However, the presence of the substrate 6 is a requirement of the manufacturing process, which may not be part of the optical security element 1 itself. The substrate 6 can be used as a part of the anti-counterfeiting product formed by the optical anti-counterfeiting element 1 . Of course, the base material 6 can also be removed in the anti-counterfeiting product, for example, in a hot stamping product, the structural layer is transferred to another carrier, and the base material 6 does not become a part of the anti-counterfeiting product. The substrate 6 does not become an essential component of the optical anti-counterfeiting element 1 . The incident light 4 is incident on the side of the substrate 6 with the diffuse reflection area 2 , and the incident light 4 is reflected by the diffuse reflection area 2 to form a plurality of reflected light rays 5 in different directions. By controlling the size and angle (angle defined by azimuth angle and pitch angle) distribution of the reflection surface element 3 of the diffuse reflection area 2, the substantially uniform diffuse reflection visual effect covers the preset observation angle set Ωv of predetermined dynamic features. In order to simplify the description without loss of generality, the direction of the incident ray 4 is set as the z direction, which is the direction perpendicular to the xy plane. The azimuth angle of the elements of the preset observation angle set Ωv is predetermined to be 0°-360°, and the pitch angle is predetermined to be 0°-35°. Accordingly, the lateral size of the reflective surface element 3 can be controlled within the range of 10 μm to 15 μm, while the vertical height can be set to 0 μm to 5 μm, and its azimuth angle is randomly selected from 0° to 360°, so that a plurality of reflective surface elements 3 The incident light 4 is reflected to the set of angles Ωr, which can cover the set of preset viewing angles Ωv. Since discrete angle information is usually used in actual design, the coverage of this application specifically means that any element in the preset observation angle set Ωv can find a sufficiently close corresponding element in Ωr, such as the angle between the two. not more than 1°. The diffuse reflection area 2 should contain enough reflection surface elements 3 to obtain sufficiently uniform and dense reflected light. In the actual design, the size of the diffuse reflection area should be more than 50 times the size of the reflection surface element 3, preferably more than 100 times. , thus containing at least 10,000 reflective surfaces 3 . The reflection surface element 3 can be designed as a wedge shape, and the projection on the xy plane can be designed as a rectangle to cover the diffuse reflection area 2 . FIG. 1 only shows that the diffuse reflection area 2 of the optical anti-counterfeiting element 1 can produce a diffuse reflection effect on the incident light 4 , and does not involve the specific dynamic characteristics and the modification method of the reflection surface element 3 .

In order to further illustrate how the reflection surface element 3 produces the diffuse reflection effect, Fig. 2 illustrates the design data of the pitch angle and azimuth angle of the reflection surface element 3. A computer program is used to randomly select the pitch angle within 0°-20°, and at 0° °-360° randomly selects the azimuth. Pseudo-random numbers are strings of numbers that appear random but are calculated by a deterministic algorithm, so they are not truly random numbers in the strict sense. However, pseudorandom numbers are widely used because the statistical properties of pseudorandom selection (such as equal probability of individual numbers or statistical independence of consecutive numbers) are usually sufficient for practical purposes, and unlike true random numbers, pseudorandom numbers are Random numbers are easily generated by computers. In FIG. 2 , there are 10×10 data for the pitch angle and the azimuth angle respectively, and a pair of data at the corresponding position determines the orientation of a reflection surface element 3 . Figure 2 also shows the data in the list of pitch angles and azimuth angles in polar coordinates. Through the polar coordinates, it can be visually seen that the angles of the reflection surface elements 3 are basically uniform and randomly distributed in a certain area. It is easy to foresee that the reflective surface element 3 can substantially reflect the incident light 4 to a specific area in a diffuse reflection manner. In particular, significantly increasing the amount of angle data will result in a more uniform and random diffuse visual effect.

Figure 3 illustrates the design data of the elevation and azimuth angles of another reflection surface. The elevation angles are randomly selected from the set {0, 2, 4, 6, 8, 10, 12, 14, 16, 18}, The azimuth angle is randomly selected from the set {0, 40, 80, 120, 160, 200, 240, 280, 320, 360}, that is, the preset angle set Ωs of the reflection surface element is:

{(0, 2, 4, 6, 8, 10, 12, 14, 16, 18);

(0, 40, 80, 120, 160, 200, 240, 280, 320, 360)}.

On the surface, the two sets contain regular angle data, but random angular distribution at different positions can still be formed by random selection (as shown in the data table of pitch and azimuth in Figure 3), which makes diffuse reflection The area has diffuse properties. In Figure 3, the pitch angle and the azimuth angle each have 10×10 data, and a pair of data at the corresponding position determines the orientation of a reflection surface element. Figure 3 also shows the data in the list of pitch and azimuth angles in polar coordinates. Through the polar coordinates, it can be visually seen that the angles of the reflection surface elements are basically uniform and randomly distributed in a certain area. When the element data in the preset angle set Ωs is greatly increased, it is easy to predict that in the polar coordinate distribution diagram in Figure 3, the data points will become dense in the axial and tangential directions, thus basically covering the designed observation angle set.

In particular, the preset observation angle set Ωv is designed as:

{(0, 4, 8, 12, 16, 20, 24, 28, 32, 36);

(0, 40, 80, 120, 160, 200, 240, 280, 320, 360)}.

When the incident light angle ωi is along the z-axis direction, the elements of the preset observation angle set Ωv and the preset angle set Ωs are related to ωi through the geometric reflection law, and the preset observation angle set Ωv and the angle of the reflected light The set Ωr is the same.

According to the animation frames that constitute the dynamic features, the specific reflection surface elements in the diffuse reflection area are modified to generate locally different reflection characteristics. Setting the incident ray angle ωi to be along the z-axis, Figures 4 and 5 provide two examples to illustrate how to determine the reflective surface to be modified.

FIG. 4 is an embodiment of determining reflective surface elements to be modified based on animation frames. 7 is an animation frame describing the change characteristics, the animation frame is defined as being observed in the direction of pitch angle=0°, azimuth angle=0°. 71 is the pattern area of the animation frame, and 72 is the background area of the animation frame. The pattern area 71 and the background area 72 have an optical contrast visible to the human eye. The size of the reflection area 21 corresponding to the animation frame 7 on the diffuse reflection area is at least not smaller than the size of the area where the animation frame 7 is located, so that the visual information of the animation frame 7 can be completely presented. Taking any point Pv on the pattern area 71 (which can also be considered as any pixel point) as an example, the corresponding point of Pv is determined in the reflection area 21 . In the reflection area 21, with Pv as the center point, within the range of ΔP, look for a reflection surface element whose pitch angle=0° or whose deviation is smaller than Δω. In the case of a small pitch angle, the difference in azimuth angle becomes less important, so the azimuth angle is not considered here. By appropriately controlling the sizes of ΔP and Δω, the reflective surface element to be modified can always be found in the reflective area 21 . For example, the projection of the reflection surface element on the xy plane is a square, its side length is 15μm, and ΔP=30μm, Δω=1°, the point (0.4°, 75.2°) can be found at the lower right of the Pv point in the reflection area 21 , the modification of the corresponding reflective surface element at this point can produce the expected visual contrast at the Pv point of the animation frame 7.

FIG. 5 is another embodiment of determining reflective surface elements to be modified according to animation frames. In

animation frame

8, 81 is the pattern area of the animation frame, and 82 is the background area of the animation frame. The pattern area 81 and the background area 82 have an optical contrast visible to the human eye. The pattern area 81 has a position change with respect to the pattern area 71 in FIG. 4 described above, and the animation frame 8 is defined as being observed in the direction of pitch angle=20°, azimuth angle=90°. The size of the reflection area 22 corresponding to the animation frame 8 on the diffuse reflection area is at least not smaller than the size of the area where the animation frame 8 is located, so that the visual information of the animation frame 8 can be completely presented. Taking any point Pw on the pattern area 81 (which can also be considered as any pixel point) as an example, the corresponding point of Pw is determined in the reflection area 22 . In the reflection area 22, taking Pw as the center point, within the range of ΔP, look for the reflection surface element that is the same as the reflection surface element determined by the angle (pitch angle=10°, azimuth angle=90°) or whose angle deviation is smaller than Δω. Appropriately control the size of ΔP and Δω, and the reflection surface element that should be modified can always be found in the reflection area 22. For example, the projection of the reflection surface element on the xy plane is a square, and its side length is 15 μm, set ΔP=30 μm, Δω =1°, the points (10.1°, 92.2°), (9.8°, 89.7°) can be found near the Pv point in the reflection area 22, and the modification of the corresponding reflection surface elements of the two points can be done in the animation frame 8 The Pw point produces the expected visual contrast.

There are many ways to modify the reflection surface element. A part or the whole of the reflection surface element 31 of the diffuse reflection area 2 in FIG. 6 is modified in a specific way, so as to generate a reflection characteristic different from that of the reflection surface element 32 . 9 is an example of the modification method. in:

91 indicates that the modification of the reflective surface element is to form a depression between the modified area (the modified area is a part or the whole of the reflective surface element) compared with the periphery (the periphery can be, for example, a reflective surface element), and the depth of the depression is selected within 0.5 μm to 3 μm, and is related to the width of the modified area. At the same time, the modification of the reflective surface element can be to flatten the modified area, so that the modified area can only reflect the incident light 4 to a specific direction, and at other viewing angles, the modified area does not provide or only provides Very little reflected light, resulting in a darker or darker visual perception than other areas.

92 means that the modification of the reflection surface element can add a secondary structure in the modified area (the modified area is the part or the whole of the reflection surface element), and the characteristic scale of the secondary structure is obviously smaller than the size of the reflection surface element, so it can be The orientation of the reflective surface is spread over the surface of the reflective surface. The lateral feature size of the secondary structure is 0.2 μm to 5 μm, which can produce diffraction or absorption of visible light. The absorption effect can be based on the principle of surface plasmon resonance absorption, and the sub-wavelength scale grating structure absorbs the incident light of a specific frequency set, thereby changing the color of the reflected light while maintaining the original reflection direction. Usually, when the depth of the subwavelength structure is relatively deep, such as 300nm to 700nm, effective absorption can be generated in a wider frequency set, thereby significantly reducing the brightness of the reflected light in this direction, that is, the subwavelength structure becomes optical absorption or optical absorption. black structure.

93 indicates that the modified reflective surface element can have a secondary structure as a whole before the modification, while observing the preset angle set Ωv to generate a uniform reflected light distribution, and to provide specific color or brightness characteristics. Therefore, the modification of the reflective surface element can make the modified area (the modified area is the part or the whole of the reflective surface element) smooth, that is, remove the secondary structure of the area to be modified, so that it can produce higher reflection to the full wavelength of visible light rate of specular reflection.

94 represents a pattern that produces sufficient contrast, and the surface on which the reflective area is located or the surface opposite the surface on which the reflective area is located may have a coating or coating. This includes reflection enhancing coatings (especially metallization layers), reflection enhancing coatings, reflective ink layers, absorbing ink layers, high refractive index material coatings, high refractive index material coatings. Reflection-enhancing coatings, coatings or reflective ink layers preferably have a color-shifting effect, i.e. a hue change of color at different viewing angles, e.g. with a Fabry-Perot interference structure, e.g. Cr(5nm)/MgF2 ₍ 500nm) /Al (50nm) structure. Alternatively, the reflective areas and reflective facets can also be imprinted in the reflective ink layer or the absorbing ink layer.

The modification to the reflective surface element may be that the thickness of the coating or coating of the modified region (the modified region is a part or the whole of the reflective surface element) is different from that of the unmodified region. For example, a reflective coating, coating or ink in the modified area and no reflective coating, coating or ink in the unmodified area; no reflective coating, coating or ink in the modified area and no reflective coating, coating or ink in the unmodified area With reflective coatings, coatings or inks.

The modification to the reflection surface element represented by 95 may be to adjust the angle of the modified area (the modified area is a part or the whole of the reflection surface element), so as to reflect the incident light to a direction exceeding Ωv. Generally, the pitch angle of the reflection surface element is increased and exceeds a minimum set jointly determined by the incident ray directions ωi and Ωv, and the incident light can be reflected to exceed the set determined by Ωv. The modified area provides little or no reflected light, resulting in a darker or darker visual perception than other areas.

The modification to the reflection surface element represented by 96 can be used in a serial manner of multiple modification methods. For example, a depression lower than the surrounding area is formed in the modified area (the modified area is a part or the whole of the reflective surface element), then a secondary structure is added in the depression, and finally the reflective coating in the secondary structure area is removed (ie. It has a different thickness from the unmodified area); a depression lower than the surrounding area is formed in the modified area, and the color ink is filled in the depression, the thickness of which is significantly larger than the thickness of the ink in the unmodified area.

The modification to the reflection surface element represented by 97 can be used in parallel with multiple modification methods. For example, a flat depression is formed in a part of the modified area (the modified area is a part or the whole of the reflective surface element), and a secondary structure is added along the direction of the reflective surface element in another part of the modified area. The modification of the reflection surface element can be used in combination of the serial combination method and the parallel combination method of the above modification methods.

The modified area can exist in part or the whole of the modified reflective surface. For an ideal planar reflective surface, the modified area will be equal to the reflective surface, while for a curved reflective surface, the modified area will be local to the reflective surface. The width of the modified region is 0.5 μm to 30 μm, preferably 2 μm to 10 μm. The modified area has one or a combination of different reflection colors, different reflection brightness, and different reflection textures than the unmodified area.

In FIG. 6 , the reflection surface element 31 and the reflection surface element 32 reflect the incident light 4 to

directions

51 and 52 , respectively. Among them, the reflected light of the modified reflection surface element 31 generates the pattern of the animation frame, that is, the modified reflection surface elements are collectively presented as the pattern of the animation frame; the reflected light of the unmodified reflection surface element 32 generates the background of the animation frame, that is The undecorated reflective surfels are collectively rendered as the background of the animation frame. The pattern area has a different optical contrast than the background area, which can be one or a combination of different colors, different brightness, and different textures visible to the human eye.

Figure 7 shows a schematic view of a banknote 10 having the optical security element of the present application, which is embedded within the banknote 10 in the form of a window security thread 101 . In addition, the optical anti-counterfeiting element can also be used in the form of labeling 102 , and an opening area 103 can be formed on the banknote base material to facilitate light-transmitting observation. It should be understood that the present application is not limited to anti-counterfeiting threads and banknotes, but can be used in various anti-counterfeiting products, such as in labels on goods and packaging, or in anti-counterfeiting documents, ID cards, passports, credit cards, health cards, etc. middle. In bank notes and similar documents, in addition to security threads and labels, wider security strips or transfer elements can be used, for example.

An embodiment of the present application provides a storage medium on which a program is stored, and when the program is executed by a processor, the design method for an optical anti-counterfeiting element according to any embodiment of the present application is implemented.

An embodiment of the present application provides a processor, where the processor is used to run a program, wherein the design method for an optical anti-counterfeiting element according to any embodiment of the present application is executed when the program runs.

An embodiment of the present application provides a device, the device includes a processor, a memory, and a program stored in the memory and executable on the processor. When the processor executes the program, the design for an optical anti-counterfeiting element according to any embodiment of the present application is implemented method.

The present application also provides a computer program product, which, when executed on a data processing device, is adapted to execute a program initialized with the steps of the design method for an optical anti-counterfeiting element of any embodiment of the present application.

As will be appreciated by those skilled in the art, the embodiments of the present application may be provided as a method, a system, or a computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present application. It will be understood that each process and/or block in the flowchart illustrations and/or block diagrams, and combinations of processes and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to the processor of a general purpose computer, special purpose computer, embedded processor or other programmable data processing device to produce a machine such that the instructions executed by the processor of the computer or other programmable data processing device produce Means for implementing the functions specified in a flow or flow of a flowchart and/or a block or blocks of a block diagram.

These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory result in an article of manufacture comprising instruction means, the instructions The apparatus implements the functions specified in the flow or flow of the flowcharts and/or the block or blocks of the block diagrams.

These computer program instructions can also be loaded on a computer or other programmable data processing device to cause a series of operational steps to be performed on the computer or other programmable device to produce a computer-implemented process such that The instructions provide steps for implementing the functions specified in the flow or blocks of the flowcharts and/or the block or blocks of the block diagrams.

In a typical configuration, a computing device includes one or more processors (CPUs), input/output interfaces, network interfaces, and memory.

Memory may include non-persistent memory in computer readable media, random access memory (RAM) and/or non-volatile memory in the form of, for example, read only memory (ROM) or flash memory (flash RAM). Memory is an example of a computer-readable medium.

Computer-readable media includes both persistent and non-permanent, removable and non-removable media, and storage of information may be implemented by any method or technology. Information may be computer readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read only memory (ROM), Electrically Erasable Programmable Read Only Memory (EEPROM), Flash Memory or other memory technology, Compact Disc Read Only Memory (CD-ROM), Digital Versatile Disc (DVD) or other optical storage, Magnetic tape cartridges, magnetic tape disk storage or other magnetic storage devices or any other non-transmission medium that can be used to store information that can be accessed by a computing device. As defined herein, computer-readable media does not include transitory computer-readable media, such as modulated data signals and carrier waves.

It should also be noted that the terms "comprising", "comprising" or any other variation thereof are intended to encompass a non-exclusive inclusion such that a process, method, article or device comprising a series of elements includes not only those elements, but also Other elements not expressly listed, or which are inherent to such a process, method, article of manufacture, or apparatus are also included. Without further limitation, an element qualified by the phrase "comprising a..." does not preclude the presence of additional identical elements in the process, method, article of manufacture or apparatus that includes the element.

The above are only examples of the present application, and are not intended to limit the present application. Various modifications and variations of this application are possible for those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the scope of the claims of the present application.

Claims

An optical anti-counterfeiting element, characterized in that the optical anti-counterfeiting element is capable of exhibiting dynamic features, and the dynamic features are pre-designed as a reproduction of a set of animation frames visible at a set of preset viewing angles Ωv, the animation frames including patterns an area and a background area forming optical contrast with the pattern area;

The optical anti-counterfeiting element has a diffuse reflection area, and the diffuse reflection area can reflect the incident light to at least the range of the preset observation angle set Ωv;

The diffuse reflection area includes a plurality of reflection surface elements, and the plurality of reflection surface elements include a modified reflection surface element and an unmodified reflection surface element that are modified in whole or in part, and the modified reflection surface element is the same as the The unmodified reflective surface elements have different reflection characteristics, wherein the modified reflective surface elements correspond to the pattern regions;

When the diffuse reflection area is illuminated by the incident light, the modified reflective surface elements together appear as the pattern of the dynamic feature, and the unmodified reflective surface elements together appear as the background of the dynamic feature .
The optical anti-counterfeiting element according to claim 1, wherein the angles of the reflection surface elements in the plurality of reflection surface elements are randomly selected from a preset angle set Ωs, wherein the elements in the preset observation angle set Ωv , the elements of the preset angle set Ωs, and the angle of the incident light are related by the law of collective reflection.
The optical anti-counterfeiting element according to claim 2, wherein the angle of the reflection surface element in the plurality of reflection surface elements is determined by the inclination angle and the azimuth angle of the reflection surface element, and the inclination angle is preferably 0° to 20° and/or the azimuth angle is preferably from 0° to 360°.
The optical anti-counterfeiting element according to claim 2, characterized in that:

The angle of the reflection surface element in the plurality of reflection surface elements is obtained by randomly selecting the elements in the preset angle set Ωs with equal probability; and/or

The angles of the reflection surface elements in the plurality of reflection surface elements are randomly selected from the preset angle set Ωs by using a pseudo-random number generation program.
The optical anti-counterfeiting element according to claim 1, wherein a lateral dimension of the reflection surface element in the plurality of reflection surface elements is 3 μm to 100 μm, preferably 10 μm to 30 μm.
The optical anti-counterfeiting element according to claim 1, wherein the reflection surface element in the plurality of reflection surface elements is a plane or a curved surface.
The optical anti-counterfeiting element according to claim 1, wherein,

at least a portion of the unmodified reflective facet is smooth or has secondary structures; and/or

At least part of the diffuse reflection area is provided with plating or coating.
The optical anti-counterfeiting element according to claim 1, wherein the modified reflective surface element is modified in whole or in part by one or more of the following multiple ways:

adding a secondary structure to the modified reflective surface;

smoothing the modified reflective surface element;

flattening the modified reflective surface element;

Setting the modified reflective surface element to have a convexity or a concave compared with the unmodified reflective surface element;

Adjusting the angle of the modified reflective surface element so that the incident light is reflected beyond the range of the preset viewing angle set Ωv; or

The thickness of the coating or coating of the modified reflective surface element is adjusted to be different from that of the unmodified reflective surface element.
The optical anti-counterfeiting element according to claim 8, wherein when the modified reflective surface element is modified by two or more of the multiple ways, the two Or two or more ways exist in parallel combination and/or serial combination.
The optical anti-counterfeiting element according to any one of claims 7 to 9, wherein the lateral feature size of the secondary structure is 0.2 μm to 5 μm.
The optical anti-counterfeiting element according to claim 1, wherein the width of the modified region of the modified reflective surface element is 0.5 μm to 30 μm, preferably 2 μm to 10 μm.
The optical anti-counterfeiting element according to claim 1, wherein the different reflection characteristics refer to the difference between the modified reflection surface element and the unmodified reflection surface element when the incident light is irradiated One or a combination of reflection colors, different reflection brightness, or different reflection textures.
A design method for an optical anti-counterfeiting element, characterized in that the design method comprises:

Designing a dynamic feature, the dynamic feature is a reproduction of a set of animation frames visible at a set of preset viewing angles Ωv, the animation frames including a pattern area and a background area that forms optical contrast with the pattern area;

Designing a diffuse reflection area for the optical anti-counterfeiting element, the diffuse reflection area can reflect incident light to at least the range of the preset viewing angle set Ωv, wherein the diffuse reflection area includes a plurality of reflection surface elements;

Based on the observation angle of each animation frame of the set of animation frames, modifying the reflection surface element corresponding to the pattern area of each animation frame to form a modified reflection surface element, so that the modified reflection surface element is Reflecting surface elements and unmodified reflection surface elements have different reflection characteristics,

When the diffuse reflection area is illuminated by the incident light, the modified reflective surface elements together appear as the pattern of the dynamic feature, and the unmodified reflective surface elements together appear as the background of the dynamic feature .
The design method according to claim 13, wherein the angles of the reflection surface elements in the plurality of reflection surface elements are randomly selected in a preset angle set Ωs, wherein the elements in the preset observation angle set Ωv, The elements of the preset angle set Ωs and the angle of the incident light are related by the law of collective reflection.
The design method according to claim 14, wherein the angle of the reflection surface element in the plurality of reflection surface elements is determined by the inclination angle and the azimuth angle of the reflection surface element, and the inclination angle is preferably 0° to 20° and/or the azimuth angle is preferably 0° to 360°.
The design method according to claim 14, wherein the angles of the reflection surface elements in the plurality of reflection surface elements are randomly selected from a preset angle set Ωs, comprising:

Obtain the angle of the reflection surface element in the plurality of reflection surface elements by randomly selecting elements in the preset angle set Ωs with equal probability; and/or

The angle of the reflection surface element in the plurality of reflection surface elements is randomly selected from the preset angle set Ωs by using a pseudo-random number generation program.
The design method according to claim 13, wherein a lateral dimension of the reflection surface element in the plurality of reflection surface elements is 3 μm to 100 μm, preferably 10 μm to 30 μm.
The design method according to claim 13, wherein the reflection surface element in the plurality of reflection surface elements is a plane or a curved surface.
The design method according to claim 13, wherein the design method further comprises:

Designing at least a portion of the unmodified reflective facet to be smooth or with secondary structures; and/or

At least part of the diffuse reflection area is designed to be coated or coated.
The design method according to claim 13, wherein, modifying the reflection surface elements corresponding to the pattern regions of the animation frames to form the modified reflection surface elements, comprising:

pixelating each animation frame in the set of animation frames;

determining the first azimuth angle and the first pitch angle of each animation frame, the first azimuth angle and the first pitch angle are determined according to the observation angle of the animation frame;

determining the second azimuth angle and the second pitch angle of each reflection surface element in the diffuse reflection area;

The following steps are performed for each animation frame in the set of animation frames:

Find a second azimuth angle and a second pitch angle that match the first azimuth angle and first pitch angle of the animation frame at the positions of the diffuse reflection area corresponding to the pixels of the pattern area in the animation frame the reflection surface element corresponding to the angle, so as to determine the reflection surface element corresponding to the pattern area of the animation frame in the diffuse reflection area;

Modifying the reflection surface element determined in the diffuse reflection area and corresponding to the pattern area of the animation frame.
The design method according to claim 20, characterized in that, at the position corresponding to the pixels of the diffuse reflection area and the pattern area in the animation frame, find the first azimuth angle and the first azimuth angle of the animation frame. A second azimuth angle that matches the pitch angle and a reflection surface element corresponding to the second pitch angle, including:

Within a preset distance range of the position of the diffuse reflection area corresponding to the pixel of the pattern area in the animation frame, find that the angle difference between the diffuse reflection area and the first azimuth angle is within a first preset angle difference range The second azimuth angle of , and the reflection surface element corresponding to the second pitch angle whose angle difference between half of the first pitch angle is within the range of the second preset angle difference.
The design method according to claim 21, wherein,

The preset distance range means that the distance from the position of the pixel in the pattern area in the animation frame is less than 100 μm, preferably less than 50 μm; and/or

The first preset angle difference range means that the angle difference from the first azimuth angle is less than 3°, preferably less than 0.5°; and/or

The second preset angle difference range means that the angle difference from the first pitch angle is less than 3°, preferably less than 0.5°.
The design method according to claim 13, wherein, modifying the reflection surface elements corresponding to the pattern regions of the animation frames to form the modified reflection surface elements, comprising:

adding a secondary structure to the modified reflective surface;

smoothing the modified reflective surface element;

flattening the modified reflective surface element;

Setting the modified reflective surface element to have a convexity or a concave compared with the unmodified reflective surface element;

Adjusting the angle of the modified reflective surface element so that the incident light is reflected beyond the range of the preset viewing angle set Ωv; or

The thickness of the coating or coating of the modified reflective surface element is adjusted to be different from that of the unmodified reflective surface element.
The design method according to claim 13, wherein,

The dynamic feature is one or a combination of translation, rotation, scaling, deformation, looming, and yin-yang transformation; and/or

The optical contrast is one or a combination of different colors, different brightness, and different textures visible to the human eye.
The design method according to claim 13, wherein the width of the modified region of the modified reflective surface element is 0.5 μm to 30 μm, preferably 2 μm to 10 μm.
An anti-counterfeiting product using the optical anti-counterfeiting element according to any one of claims 1 to 12.
A data carrier, characterized in that the data carrier has the optical anti-counterfeiting element according to any one of claims 1 to 12, or has the anti-counterfeiting product according to claim 26.