CN115230364B

CN115230364B - Optical security element, method for designing an optical security element, security product and data carrier

Info

Publication number: CN115230364B
Application number: CN202110449753.0A
Authority: CN
Inventors: 孙凯; 朱军
Original assignee: Zhongchao Special Security Technology Co Ltd; China Banknote Printing and Minting Group Co Ltd
Current assignee: Zhongchao Special Security Technology Co Ltd; China Banknote Printing and Minting Group Co Ltd
Priority date: 2021-04-25
Filing date: 2021-04-25
Publication date: 2024-03-29
Anticipated expiration: 2041-04-25
Also published as: CN115230364A; EP4331858A1; WO2022227740A1

Abstract

The embodiment of the invention provides an optical anti-counterfeiting element, a design method thereof, an anti-counterfeiting product and a data carrier, and belongs to the field of anti-counterfeiting. The optical security element has a diffuse reflection region capable of reflecting incident light into at least a range of a preset set of viewing angles Ω; the diffuse reflection area comprises a plurality of reflection surface elements, the plurality of reflection surface elements comprise a modified reflection surface element and an unmodified reflection surface element which are modified wholly or partially, the modified reflection surface element and the unmodified reflection surface element have different reflection characteristics, and the modified reflection surface element corresponds to a pattern area; when the diffuse reflection area is irradiated by the incident light, the decorated reflection surface elements jointly present a pattern of dynamic characteristics, and the unmodified reflection surface elements jointly present a background of dynamic characteristics. The optical anti-counterfeiting element has simple manufacturing process and can flexibly realize dynamic characteristics such as color and/or brightness contrast and the like.

Description

Optical security element, method for designing an optical security element, security product and data carrier

Technical Field

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

Background

In order to prevent counterfeiting by means of scanning, copying and the like, optical anti-counterfeiting technology is widely adopted in various high-security or high-added-value products such as banknotes, financial notes and the like, and a very good effect is achieved.

At present, attractive technology is to combine a microstructure determined by plate making with a light-variable layer, as disclosed in chinese patents CN 102712207a and CN 107995894A, and modulate the brightness distribution of reflected light by a micro-reflecting surface designed in advance, so as to achieve a dynamic effect, and can superimpose an interference coating to achieve a combination of color change and dynamic effect. This generally produces a variety of motion effects of patterns, such as lines, circles, curves, or words, and may produce a three-dimensional perspective. However, in most cases, the color tone of the pattern and the background can be the same, the contrast relationship is also basically single, and it is difficult to realize dynamic characteristics of various colors or arbitrary contrast relationship.

An exhibition with three-dimensional depth effect can also be produced by a moire magnification construction based on micro lenses and micro patterns, as described for example in document WO 2005/052650 A2. Here, a periodic display diagram made up of many small micropatterns is magnified with a grid made up of microlenses having similar but not identical periods. In this way, a stereoscopic sensation can be generated that is significantly in front of or behind the actual surface, or so-called orthogonal parallax motion can be generated. However, such a moire magnification configuration is disadvantageous in that it is relatively complicated to manufacture, requires two imprinting steps for the microlens and micropattern, and requires precise alignment between the two steps.

Finally, as described for example in WO2014/108303A1, magnetically aligned reflective pigments are aligned with magnets having a corresponding shape, thereby creating a bright (especially annular) dynamic effect that may include a depth effect. This effect is very bright and easily visible, but the required magnetic ink is expensive and the kind and resolution of the effect is limited by the available magnets and is difficult to adjust at will.

Therefore, there is a need to develop an optical security element that is simple in manufacturing process and flexible in achieving dynamic characteristics of color and/or contrast.

Disclosure of Invention

An object of embodiments of the present invention is to provide an optical security element, a design method thereof, a security product, and a data carrier, wherein the optical security element has a simple manufacturing process and can flexibly realize dynamic characteristics such as color and/or brightness contrast.

To achieve the above object, an embodiment of the present invention provides an optical security element capable of exhibiting a dynamic characteristic, which is pre-designed as reproduction of a set of animated frames visible at a set of pre-set viewing angles Ω, the animated frames comprising a pattern area and a background area forming an optical contrast with the pattern area; the optical anti-counterfeiting element is provided with a diffuse reflection area, and the diffuse reflection area can reflect incident light to at least the range of the preset observation angle set omega v; the diffuse reflection area comprises a plurality of reflection surface elements, the plurality of reflection surface elements comprise a modified reflection surface element and an unmodified reflection surface element which are modified wholly or partially, the modified reflection surface element and the unmodified reflection surface element have different reflection characteristics, and the modified reflection surface element corresponds to the pattern area; when the diffuse reflection area is irradiated by the incident light, the modified reflecting surface elements are jointly presented as the pattern of the dynamic characteristics, and the unmodified reflecting surface elements are jointly presented as the background of the dynamic characteristics.

Optionally, the angles of the reflecting surface elements in the plurality of reflecting surface elements are randomly selected in a preset angle set Ω, where elements in the preset observation angle set Ω, elements in the preset angle set Ω, and angles of the incident light are related by a set reflection law.

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

Optionally, the angles of the reflecting surface elements in the plurality of reflecting surface elements are obtained by randomly selecting the element in the preset angle set Ω with equal probability; and/or the angles of the reflecting surface elements in the plurality of reflecting surface elements are randomly selected from the preset angle set omega s by using a pseudo-random number generating program.

Optionally, the lateral dimension of a reflective element of the plurality of reflective elements is 3 μm to 100 μm, preferably 10 μm to 30 μm.

Optionally, the reflective surface element of the plurality of reflective surface elements is planar or curved.

Optionally, at least a portion of the unmodified reflective surface element is smooth or has a secondary structure; and or at least part of the diffuse reflection area is provided with a plating or coating.

Optionally, the modified reflective surface element is modified in whole or in part by one or more of the following: adding a secondary structure to the modified reflective surface element; smoothing the modified reflective surface element; flattening the modified reflective surface element; providing the modified reflective surface element with a protrusion or depression compared to the unmodified reflective surface element; adjusting the angle of the modified reflecting surface element so that the incident light is reflected to a range beyond the preset observation angle set Ω; or the thickness of the plating 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 where the modified reflecting surface element is modified by two or more of the plurality of ways, the two or more ways exist in parallel combination and/or serial combination.

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

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

Optionally, the 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 irradiates.

Correspondingly, the embodiment of the invention also provides a design method for learning the anti-counterfeiting element, which comprises the following steps: designing an dynamic characteristic, wherein the dynamic characteristic is the reproduction of a group of animation frames visible at a preset observation angle set omega v, and the animation frames comprise pattern areas and background areas forming optical contrast with the pattern areas; a diffuse reflection area designed for the optical security element, the diffuse reflection area being capable of reflecting incident light into at least the range of the set of preset viewing angles Ω, wherein the diffuse reflection area comprises a plurality of reflective surface elements; modifying, based on an observation angle of each animation frame of the set of animation frames, a reflection surface element corresponding to the pattern region of each animation frame to form a modified reflection surface element, such that the modified reflection surface element and an unmodified reflection surface element have different reflection characteristics, wherein when the diffuse reflection region is irradiated by the incident light, the modified reflection surface element is jointly presented as a pattern of the dynamic feature, and the unmodified reflection surface element is jointly presented as a background of the dynamic feature.

Optionally, the angles of the reflecting surface elements in the plurality of reflecting surface elements are randomly selected in a preset angle set Ω, including: obtaining angles of reflecting surface elements in the plurality of reflecting surface elements by randomly selecting the element in the preset angle set omega s at equal probability; and/or randomly selecting the angles of the reflecting surface elements in the plurality of reflecting surface elements from the preset angle set omega s by utilizing a pseudo-random number generation program.

Optionally, the method further comprises: designing at least a portion of the unmodified reflective surface element to be smooth or with a secondary structure; and/or at least a part of the diffuse reflection area is designed to be provided with a plating or coating.

Optionally, modifying the reflection surface element corresponding to the pattern area of each animation frame to form a modified reflection surface element, including: pixelating each animation frame of the set of animation frames; determining a first azimuth angle and a first pitch angle of each animation frame, wherein the first azimuth angle and the first pitch angle are determined according to the observation angle of the animation frame; determining a second azimuth angle and a second pitch angle of each reflecting surface element in the diffuse reflection area; the following steps are performed for each animation frame of the set of animation frames: searching a reflection surface element corresponding to a second azimuth angle and a second pitch angle matched with 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 a pattern area in the animation frame, so as to determine the reflection surface element corresponding to the pattern area of the animation frame in the diffuse reflection area; and modifying the reflection surface elements which are determined in the diffuse reflection area and correspond to the pattern area of the animation frame.

Optionally, searching for a reflection surface element corresponding to a second azimuth angle and a second pitch angle matched with the first azimuth angle and the first pitch angle of the animation frame at a position of the diffuse reflection area corresponding to a pixel of a pattern area in the animation frame comprises: and searching a reflection surface element corresponding to a second azimuth angle of which the angle difference between the first azimuth angles is in a first preset angle difference range and a second pitch angle of which the angle difference between one half of the first pitch angle is in a second preset angle difference range in a preset distance range of the diffuse reflection region corresponding to the position of the pixel of the pattern region in the animation frame.

Optionally, the preset distance range indicates a distance from a position of a pixel of a pattern area in the animation frame of less than 100 μm, preferably less than 50 μm; and/or said first predetermined range of angular differences means that the angular difference from said first azimuth angle is less than 3 °, preferably less than 0.5 °; and/or said second predetermined range of angular differences means an angular difference with said first pitch angle of less than 3 °, preferably less than 0.5 °.

Optionally, modifying the reflection surface element corresponding to the pattern area of each animation frame to form a modified reflection surface element, including: adding a secondary structure to the modified reflective surface element; smoothing the modified reflective surface element; flattening the modified reflective surface element; providing the modified reflective surface element with a protrusion or depression compared to the unmodified reflective surface element; adjusting the angle of the modified reflecting surface element so that the incident light is reflected to a range beyond the preset observation angle set Ω; or the thickness of the plating or coating of the modified reflective surface element is adjusted to be different from that of the unmodified reflective surface element.

Optionally, the dynamic characteristic is one or a combination of translation, rotation, scaling, deformation, invisibility and yin-yang conversion; and/or the optical contrast is one or a combination of different colors, different brightness and different textures which are visible to human eyes.

Correspondingly, the embodiment of the invention also provides an anti-counterfeiting product using the optical anti-counterfeiting element.

Correspondingly, the embodiment of the invention also provides a data carrier, which is provided with the optical anti-counterfeiting element or the anti-counterfeiting product.

The optical anti-counterfeiting element provided by the embodiment of the invention has simple manufacturing process, can flexibly realize dynamic characteristics such as color and/or brightness contrast, and can display various multicolor dynamic characteristics macroscopically, and simultaneously has no directly identifiable arrangement rule microscopically, so that the difficulty of multi-dimensional enhancement counterfeiting such as microstructure design and manufacturing process is improved.

Additional features and advantages of embodiments of the invention will be set forth in the detailed description which follows.

Drawings

The accompanying drawings are included to provide a further understanding of embodiments of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain, without limitation, the embodiments of the invention. In the drawings, the illustrations are not drawn to scale for clarity. In the drawings:

FIG. 1 is a schematic illustration of the diffuse reflection of incident light by the diffuse reflection regions of an optical security element;

FIG. 2 is an example of a design method for pitch and azimuth of a reflective surface element;

FIG. 3 is an example of another design method for pitch and azimuth of a reflective surface element;

FIG. 4 is an embodiment of determining reflective surface elements to be modified from an animation frame;

FIG. 5 is another embodiment of determining reflective surface elements to be modified from an animation frame;

FIG. 6 is a schematic illustration of a partial or complete modification of a modified reflective surface element;

fig. 7 is a schematic view of the use of an optical security element on a banknote.

Detailed Description

The following describes the detailed implementation of the embodiments of the present invention with reference to the drawings. It should be understood that the detailed description and specific examples, while indicating and illustrating the invention, are not intended to limit the invention.

In one aspect, embodiments of the present invention provide an optical anti-counterfeiting element capable of exhibiting a dynamic characteristic that is pre-designed as a reproduction of a set of animated frames visible at a preset set of viewing angles Ω, the animated frames comprising a pattern area and a background area that forms an optical contrast with the pattern area; the optical anti-counterfeiting element is provided with a diffuse reflection area, and the diffuse reflection area can reflect incident light to at least the range of the preset observation angle set omega v; the diffuse reflection area comprises a plurality of reflection surface elements, the plurality of reflection surface elements comprise a modified reflection surface element and an unmodified reflection surface element which are modified wholly or partially, the modified reflection surface element and the unmodified reflection surface element have different reflection characteristics, and the modified reflection surface element corresponds to the pattern area; when the diffuse reflection area is irradiated by the incident light, the modified reflection surface elements are jointly presented as the pattern of the dynamic characteristics, the unmodified reflection surface elements are jointly presented as the background of the dynamic characteristics, namely the modified reflection surface elements jointly reproduce the pattern of the dynamic characteristics, and the unmodified reflection surface elements jointly reproduce the background of the dynamic characteristics.

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

When the diffuse reflection area is irradiated by incident light, the animation frame can be observed under the corresponding observation angle of each animation frame, wherein the pattern of the observed animation frame is represented by a decorated reflection surface element, and the background of the observed animation frame is represented by an unmodified reflection surface element.

The "a group of animation frames visible in the preset observation angle set Ω v" in the embodiment of the present invention means that the observation angles correspond to the animation frames one by one, and one observation angle corresponds to one animation frame.

The dynamic characteristics in the embodiment of the invention essentially refer to dynamic characteristics which appear when the observation angle is changed. In principle, the viewing angle may be the angle of one or more of the three elements of the light source (i.e. the incident light), the element and the observer. For example, the optical security element or the article with the optical security element is held in the hand with the illumination source and eye position unchanged, and the designed dynamic characteristics can be seen by shaking the element back and forth or left and right, i.e. changing the angle of the optical security element. The present invention is to simplify the description by defining the viewing direction and thus the viewing angle by the line connecting the eyes of the observer with the point of view. It should be noted that this definition does not materially affect or limit any of the relevant aspects of the embodiments of the invention. The observation angle is a three-dimensional space parameter, so that the observation angle needs to be accurately described by being decomposed into at least two angles. For example, the pitch angle and the azimuth angle can be described together, and the included angles between the observation direction and three coordinate axes of x, y and z can be also used for describing together. In the xyz coordinate defined in the embodiment of the present invention, the xy plane is the plane where the optical anti-counterfeiting element is located, the x axis may be the longitudinal direction of the optical anti-counterfeiting element, the y axis may be the transverse direction of the optical anti-counterfeiting element, and the z axis may be the axis perpendicular to the optical anti-counterfeiting element.

The pattern of the animated frames may be designed as letters, numbers, characters, symbols or geometric shapes (especially circles, ovals, triangles, rectangles, hexagons or stars, etc.). The dynamic characteristics described above generally refer to any translational motion, rotation, scaling, deformation, invisibility, yin-yang conversion, etc. of the design pattern that is presented by the element and is directly visible to the human eye, and may also be any combination of these dynamic characteristics. The translation may be designed to translate the design pattern in a specific direction, or may be designed to translate in multiple directions, with the translation direction being associated with the viewing direction. One common combination feature is that the shape changes, such as a circle illusion, to a square as the position of the design animation frame pattern changes. The dynamic feature can have the orthographic parallax motion behavior of the pattern, namely the motion direction of the pattern is always perpendicular to the change of the observation direction, and the dynamic feature further attracts the attention of an observer through the anti-intuitiveness phenomenon. The motion of the animated frame pattern may create a stereoscopic impression floating above or below the plane of the element by the principle of binocular horizontal parallax. The pattern may also include a plurality of sub-patterns exhibiting the same or different athletic performance and/or the same or different float heights or float depths. In particular, the pattern may comprise at least a first curve and a second curve, which curves appear as a first or second target curve located at a central position of the first or second region, respectively, when viewed from the first or second viewing direction, respectively. When the security element is tilted, the two curves preferably move in different (preferably opposite) directions, thereby creating a particularly dynamic appearance. It will be appreciated that in the same way, the pattern of the security element may also include more than two curves which may move in the same or different directions when the security element is tilted. For example, the curves in the form of alphanumeric strings may alternately exhibit different movement behaviors, such as alternately floating above or below the plane of the planar pattern area, and moving according to their floating height when tilted. For specific principles of various dynamic characteristics, reference may be made to the prior patent texts CN 102712207A, CN 107995894A, WO 2005/052650 A2, etc. The terms "pattern" and "pattern area" may be used interchangeably in embodiments of the present invention.

The dynamic characteristics can be represented by a group of pictures generated by computer software such as digital calculation software, pattern processing software and the like in specific design. For example, using a bitmap in the format of bmp, design patterns of different colors and a common background of the patterns are represented by gray values of 0-255. Each picture corresponds to visual information presented to the human eye at a particular viewing angle, known as a frame of animation of the designed motion-sensing feature.

The observation angle set Ω v refers to that all preset dynamic characteristics can be seen when the observation angle of the human eye changes in the set. The optical security element may reflect illumination beyond the collection, but these reflected light rays may not be correlated with the designed animation feature, and may also provide darker or darker visual information to the animation feature. The set of viewing angles qv may be described in terms of azimuth and pitch angles, for example, azimuth angles may be designed to be 0-360 ° and pitch angles may be 0-35 ° or 10-50 ° etc., i.e. the dynamic characteristics may be seen in the region where the human eye is in the conical shape. The setting of the angle parameter depends on the purpose of the designer, the lighting environment owned by the observer, the viewing habit, etc.

The reflective surface elements of the diffuse reflective area may in particular be flat planar surfaces, each reflective surface element being characterized by a certain inclination angle with respect to the plane in which the pattern area of the dynamic feature is located and a certain rotation angle with respect to the x-axis direction, whereby the pitch angle and the azimuth angle may be used to determine the orientation of the reflective surface element (which may also be referred to as the angle of the reflective surface element). Of course, other parameters may be used to determine the orientation of the elements, in particular parameters that are orthogonal to each other, such as two orthogonal components of the orientation of the reflective elements. Alternatively, the reflective surface element of the diffuse reflection area may be a curved surface. Mathematically, a surface can continue to break down into more nearly planar and smaller area bins, with no substantial difference between the surface and the flat plane in a particular design. To produce sufficiently fine patterns and continuously varying dynamic characteristics, the reflective surface elements are preferably of a size less than the human eye's recognition capability, which is typically about 100 μm at apparent distances, with closer distances improving the resolution. Thus, the size of the bin is not preferably greater than 100 μm. On the other hand, too small a bin will produce significant diffraction of light, affecting the dynamic characteristic color stability. Reflective surface elements having a lateral dimension of 3 μm to 100 μm may produce sufficiently fine features without producing significant diffractive iridescence, and the lateral dimension may further preferably be 10 μm to 30 μm. The projection of the reflective surface element on the plane of the dynamic pattern is usually selected to be rectangular, and can be any pattern which is beneficial to spreading the plane, such as triangle, hexagon or irregular shape.

In embodiments of the invention, the unmodified reflective surface element may be smooth or have a secondary structure. It will be appreciated that unmodified portions may also be present in the modified reflective element, which may also be smooth or have a secondary structure. In some alternative embodiments, the diffusely reflective region may be provided with a plating or coating on at least a portion of the diffusely reflective region.

The main function of the reflective surface elements forming the diffuse reflection area is to generate a uniform reflected light at least at a set of predetermined viewing angles qv, similar to the visual impression of diffuse reflection generated by general office paper. To this end, the orientation of the reflective surface elements is irregularly varied or chosen within the predetermined set of angles Ω, in particular randomly or pseudo-randomly chosen (i.e. may be randomly chosen within said predetermined set of angles Ω). Pseudo-random numbers are strings of numbers that appear random but are calculated by deterministic algorithms, so they are not truly random numbers in a strict sense. However, pseudo-random numbers are widely used because the statistical properties of pseudo-random selection (e.g., equal probability of individual numbers or statistical independence of successive numbers) are generally sufficient to meet the requirements of practical use, and unlike true random numbers, pseudo-random numbers are easily computer-generated. Specifically, the random change of the orientation of the reflecting surface element in the preset angle set Ω can be achieved by the random change or selection of the pitch angle and the random change or selection of the azimuth angle. The elements in the preset observation angle set Ω, the elements of the preset angle set Ω, and the angle ωi of the incident light are related by the law of collective reflection. The predetermined set of angles Ω is selected to reflect incident light uniformly at least into the set of viewing angles Ω, so that Ω covers a minimum set determined by the angles ωi and Ω together. Equivalently, a reflective region made up of multiple reflective surface elements reflects incident light to a set of angles Ω r, which covers a set of viewing angles Ω v, i.e. Ω v is a subset or proper subset of Ω r. Preferably, Ω is designed as a minimum set determined jointly by the incident light angles ωi and Ω, i.e. Ω is identical to Ω r. For example, when incident light is normally incident on the surface of the optical security element, i.e. the optical security element is in the xy plane, the incident light is along the z direction, according to the law of geometrical reflection, the azimuth angle of the element of Ω is the same as the azimuth angle of the element of Ω, and the pitch angle of the element is half the pitch angle of the element of Ω.

To achieve the variation characteristic, the diffuse reflection area needs to be modified according to each pixel point of each animation frame, so as to change the reflection light distribution uniformly in the observation angle set Ω. The size of the diffuse reflection area should be larger than the area occupied when all the animation frames are presented together, so that each animation frame can correspond to the diffuse reflection area without scaling, and each pixel of the pattern area of the animation frame can find a corresponding position point in the diffuse reflection area, and the position point is to be decorated.

According to the position Pv of the pattern area contained in a certain animation frame and the observed angle ωv, the position Ps and the angle ωs of the reflecting surface element to be modified are found, for example, the position and the angle of the reflecting surface element to be modified can be found per pixel. In principle, pv and Ps should be the same position, and the reflection law of geometric optics needs to be satisfied between ωv, ωs and the angle ωi of the incident light, that is, the incident light, the normal of the reflecting surface element are in the same plane, and the incident angle is equal to the reflection angle. Here, ωs=f (ωv, ωi) indicates that there is a quantitative relationship among the three, and specific calculation formulas can be found in general optical textbooks, for example, born's optical principle: electromagnetic theory of light propagation, interference and diffraction. In practical design, since the angles of the reflective surface elements are randomly selected within the preset angle set Ω, when pv=ps, the angle ωs of the reflective surface element at the position may not exactly satisfy the geometric reflection law with ωv and ωi. Thus, the reflective surface element to be modified can be found within a certain range of positions and a certain range of angles, namely:

Ps∈(Pv-ΔP,Pv+ΔP)

ωs∈(f(ωv,ωi)-Δω,f(ωv,ωi)+Δω)

The position deviation deltap and the angle deviation deltaω are specifically determined according to the size of the reflective surface element, the resolution of the human eye to the angle and the size, and the designed dynamic characteristics, and the principle is that at least one reflective surface element to be modified can be found, and meanwhile, no difference between the reflective surface element and the design pattern is generated. The positional deviation ΔP is generally less than 100 μm, preferably less than 50. Mu.m. The angle 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, and should be less than 3 °, preferably less than 0.5 °.

In general, the pitch angles of the two reflective surface elements are respectively defined as θ ₁ ，θ ₂ Azimuth angles are respectivelyThe angle between the normal lines of the two reflecting surface elements can be determined byThe formula of the face is calculated:

each animation frame may be pixelated, when specifically performed. In the alternative, only the pattern area of each animation frame may be pixelated. The essence of pixelation is that an animation frame is divided into, for example, nxM small areas, each of which may, for example, be very small in area. For example, the width of each small region according to the embodiment of the present invention may be 0.5 μm to 10 μm, preferably 2 μm to 4 μm, and the length of each small region may be 0.5 μm to 10 μm, preferably 2 μm to 4 μm. Finding the reflective surface element to be modified is finding the reflective surface element corresponding to the pixel of the pattern area.

Further, a first azimuth angle and a first pitch angle may be determined for each animation frame, each animation frame corresponding to a particular viewing angle one-to-one, such that the first azimuth angle and the first pitch angle may be determined based on the viewing angle of the animation frame. In the embodiment of the invention, 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 (also called the residual angle from 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.

A second azimuth angle and a second pitch angle of each reflective element of the diffuse reflective area may further be determined. Each element within the preset angle set Ω may be composed of an azimuth angle and a pitch angle, and thus, the second azimuth angle and the second pitch angle of each reflection element may be stored in advance. The second azimuth and the second pitch of each reflective element of the diffuse reflective area can thus be obtained from a database.

The following steps may be performed for each animation frame of the set of animation frames: and searching reflection surface elements corresponding to a second azimuth angle and a second pitch angle matched with the first azimuth angle and the first pitch angle of the animation frame at positions of the diffuse reflection area corresponding to pixels of the pattern area in the animation frame, so that the reflection surface elements corresponding to the pattern area of the animation frame are determined in the diffuse reflection area. For example, the set of animation frames may be vertically projected onto the diffuse reflection area in a uniform proportion, such that a location on the diffuse reflection surface corresponding to each pixel in each animation frame may be determined. Finding a reflective bin corresponding to a second azimuth and a second pitch that match a first azimuth and a first pitch of an animation frame may include: and searching a reflection surface element corresponding to a second azimuth angle of which the angle difference between the first azimuth angles is in a first preset angle difference range and a second pitch angle of which the angle difference between one half of the first pitch angle is in a second preset angle difference range in a preset distance range of the diffuse reflection region corresponding to the position of the pixel of the pattern region in the animation frame. Alternatively, in the case of a small pitch angle, the difference in azimuth angle becomes less important. Therefore, in the case where the pitch angle is relatively small, the reflection surface element corresponding to the second pitch angle in which the angle difference between the first pitch angles is one half of the second pitch angle is within the second preset angle difference range may be found only within the preset distance range without considering the azimuth angle. Alternatively, when the pitch angle is about 2 ° or less, the difference in orientation due to the difference in azimuth angle may be considered insignificant, and the azimuth angle may be disregarded. The preset distance range indicates that a distance between positions of the diffuse reflection area corresponding to pixels of a pattern area in the animation frame is less than 100 μm, preferably less than 50 μm. The first predetermined angular difference range means that the angular difference from the first azimuth angle is less than 3 °, preferably less than 0.5 °. The second predetermined range of angular differences means that the angular difference from one half of the first pitch angle is less than 3 °, preferably less than 0.5 °. For a pixel of the pattern area, one or more eligible reflective elements may be found in the diffuse reflective area, which may each be decorated. After finding the reflection bins in the diffuse reflection area that match each pixel of the pattern area of the animated frame, these matching reflection bins form reflection bins corresponding to the pattern area of the animated frame. And modifying the reflection surface element formed in the diffuse reflection area and corresponding to the pattern area of each animation frame, so that the modified reflection surface element can be formed.

The modification of the reflecting surface element can add a secondary structure to the modified reflecting surface element, wherein the characteristic dimension of the secondary structure is obviously smaller than that of the reflecting surface element, so that the secondary structure can be spread on the surface of the reflecting surface element along the trend of the reflecting surface element. The secondary structure has a lateral characteristic dimension of 0.2 μm to 5 μm and can diffract or absorb visible light. The absorption effect can absorb incident light of a specific frequency set through a grating structure with a sub-wavelength scale by the principle of surface plasmon resonance absorption, so that the color of reflected light is changed, and the original reflection direction is maintained. Typically, when the depth of the sub-wavelength structure is relatively deep, such as 300nm to 700nm, efficient absorption can occur over a broader set of frequencies, thereby significantly reducing the brightness of the reflected light in that direction, i.e., the sub-wavelength structure becomes an optically absorptive or optically black structure.

The modified reflective surface element may be integrally provided with said secondary structure prior to modification, while producing a uniform reflected light distribution within the collection of viewing angles qv and providing specific color or brightness characteristics. Thus, the modification of the reflective surface element may 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 the modified reflective surface element generates specular reflection with higher reflectivity for the whole visible light wave band. Alternatively, at least a portion of the unmodified reflective surface element may be provided to be smooth or with a secondary structure.

The modification of the reflective surface element may be to flatten the modified reflective surface element so that the modified reflective surface element reflects incident light only to a specific one of the opposite directions. At other viewing angles, none or only little reflected light is provided by the modified region, resulting in a darker or darker visual perception than the other regions.

The modification to the reflection surface element may be to adjust the angle of the modified reflection surface element, so that the modified reflection surface element can reflect all the light rays incident to the modified reflection surface element to a direction exceeding the preset observation angle set Ω. The pitch angle of the reflecting surface element is generally increased beyond a minimum set defined by the directions ωi and ωv of the incident light, i.e. the incident light is reflected beyond the set defined by ωv. The modified reflective surface element provides no or little reflected light, thereby producing a darker or darker visual perception than other areas.

To create a pattern of sufficient contrast, the surface on which the modified reflective surface element is located or the surface opposite the surface on which the modified reflective surface element is located (e.g., the unmodified reflective surface element) may be provided with a plating or coating. This includes reflection enhancing coatings (especially metallization layers), reflection enhancing coatings, reflective ink layers, absorbing ink layers, high refractive index material coatings, and high refractive index material coatings. The reflection enhancing coating, coating or reflective ink layer preferably has a color shifting effect, i.e. a change in hue of the color at different viewing angles, for example using a fabry perot interference structure. Alternatively, the reflective regions and reflective surface elements may also be imprinted in the reflective ink layer or the absorbing ink layer.

The modification of the reflecting surface element can be to form a bulge or a recess on the modified reflecting surface element than the area with the periphery not modified; alternatively, the modification of the reflective surface element may be such that the coating or thickness of the coating of the modified reflective surface element is different from that of the unmodified region. For example, a reflective coating, coating or ink is present on the modified reflective surface element, while a reflective coating, coating or ink is absent on the unmodified reflective surface element; or no reflective coating, coating or ink on the modified reflective surface element, while the non-modified reflective surface element has a reflective coating, coating or ink.

The modification of the reflecting surface element can be a serial combination of the above-mentioned modification modes. For example, forming a depression lower in the modified reflective surface element than the unmodified reflective surface element, then adding a secondary structure in the depression, and finally removing the reflective coating in the secondary structure region (i.e., having a different thickness than the reflective coating of the unmodified reflective surface element); alternatively, depressions lower than the unmodified reflective surface element are formed in the modified reflective surface element, and the depressions are filled with color ink, the thickness of which is significantly greater than the thickness of the ink in the unmodified reflective surface element. The modification of the reflecting surface element can be combined with a plurality of modification modes in parallel. For example, a flat depression is formed in a portion of the modified reflective surface element, and a secondary structure is added to another portion of the modified reflective surface element along the orientation of the reflective surface element. The modification of the reflecting surface element can be the re-combination of the serial combination mode and the parallel combination mode of the modification mode.

The modified region may be present in part or in whole of the modified reflective surface element. For an ideal planar reflective surface element, the modified region would be equal to the reflective surface element. Whereas for a curved reflective surface element, a modified region will be present in a part of the reflective surface element. In the embodiment of the present invention, the width of the modified region is 0.5 μm to 20 μm, preferably 2 μm to 10 μm, depending on the visibility of the generated pattern. The modified reflective surface element has one or a combination of different reflective colors, different reflective brightness and different reflective textures than the unmodified reflective surface element. Alternatively, the modified regions may have one or a combination of different reflective colors, different reflective brightnesses, different reflective textures than the unmodified regions.

The optical anti-counterfeiting element is characterized in that in the observation angle set omega v, decorated reflecting surface elements are jointly presented as patterns of animation frames, and unmodified reflecting surface elements are jointly presented as backgrounds of the animation frames. The pattern area has different optical contrast than the background area, and can be one or a combination of different colors, different brightness and different textures which are visible to human eyes.

The embodiment of the invention also provides a design method for learning the anti-counterfeiting element, which comprises the following steps: designing an dynamic characteristic, wherein the dynamic characteristic is the reproduction of a group of animation frames visible at a preset observation angle set omega v, and the animation frames comprise pattern areas and background areas forming optical contrast with the pattern areas; a diffuse reflection area designed for the optical security element, the diffuse reflection area being capable of reflecting incident light into at least the range of the set of preset viewing angles Ω, wherein the diffuse reflection area comprises a plurality of reflective surface elements; modifying, based on an observation angle of each animation frame of the set of animation frames, a reflection surface element corresponding to the pattern region of each animation frame to form a modified reflection surface element, such that the modified reflection surface element and an unmodified reflection surface element have different reflection characteristics, wherein when the diffuse reflection region is irradiated by the incident light, the modified reflection surface element is jointly presented as a pattern of the dynamic feature, and the unmodified reflection surface element is jointly presented as a background of the dynamic feature.

The dynamic characteristics can be represented by a group of pictures generated by computer software such as digital calculation software, pattern processing software and the like in specific design. For example, using a bitmap in the format of bmp, design patterns of different colors and a common background of the patterns are represented by gray values of 0-255. Each picture corresponds to visual information presented to the human eye at a particular viewing angle, known as a frame of animation of the designed motion-sensing feature. The specific working principle and benefits of the design method for an optical security element according to the embodiments of the present invention may refer to the description of the optical security element according to the embodiments of the present invention, and will not be repeated here.

Correspondingly, the embodiment of the invention also provides an anti-counterfeiting product using the optical anti-counterfeiting element according to any embodiment of the invention. The anti-counterfeiting product can be in the forms of anti-counterfeiting lines, anti-counterfeiting strips, anti-counterfeiting marks and the like. Embodiments of the invention also provide a data carrier having a security element according to any of the embodiments of the invention or a security product according to any of the embodiments of the invention, which security element or security product may be arranged in an opaque region of the data carrier and in or over a transparent window region or through opening in the data carrier. The data carrier may in particular be a value document, such as a banknote (in particular a paper banknote, a polymer material banknote or a film composite banknote), a stock certificate, a ticket, a check, a high-value ticket, but also an identification card, such as a credit card, a bank card, a cash card, an authorization card, a personal identification card, or a personal information page of a passport, etc.

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

FIG. 1 is a schematic illustration of the diffuse reflection of incident light by the diffuse reflection region of an optical security element. The plane in which the element 1 lies is defined as the xy-plane, and the diffuse reflection area 2 is constituted by a plurality of reflection facets 3. In fig. 1, the optical security element has a substrate 6, on one side of which the diffusely reflective region 2 is located. However, the presence of the substrate 6 is a requirement of the processing process, which may not be part of the optical security element itself. Substrate 6 may be part of the security product formed by optical security element 1. Of course, the substrate may also be removed from the security product, for example, in a thermoprinted product, the structural layer being transferred to another carrier, without the substrate 6 being part of the security product. The substrate 6 does not form an essential part of the component 1. The incident light 4 is incident on the side of the substrate with the reflection area, and the incident light 4 forms a plurality of reflected light rays 5 in different directions through the reflection effect of the diffuse reflection area 2. By controlling the size and angular (e.g. defined by azimuth and pitch) distribution of the reflective elements of the diffuse reflective area 2, a substantially uniform diffuse reflective visual effect covers a predetermined set of viewing angles qv of the dynamic feature. For simplicity of description, the direction of the incident light 4 is set to the z direction, which is a direction perpendicular to the xy plane, without losing generality. Whereas the azimuth angle of the elements of the set qv is predetermined to be 0-360 deg., and the pitch angle is predetermined to be 0-35 deg.. Accordingly, the lateral dimensions of the reflective surface elements can be controlled in the range of 10 μm to 15 μm and the longitudinal height can be set to 0 to 5 μm with the azimuth angle randomly selected from 0-360 °, so that the incident light 4 is reflected by the plurality of reflective surface elements to the angle set Ω, which can cover the observation angle set Ω. Because discrete angle information is generally adopted in practical design, the coverage of the invention specifically means that any element in the set Ω can find a corresponding element close enough to it in Ω, for example, the included angle between the two elements is not more than 1 °. The diffuse reflection area 2 should contain enough reflective surface elements 3 to obtain a sufficiently uniform and dense reflected light, and in practical design, the diffuse reflection area should have a size that is more than 50 times, preferably more than 100 times, the size of the reflective surface elements, so as to contain at least 10000 reflective surface elements. The reflective surface element may be designed as a wedge and the projection in the xy plane may be designed as a rectangle to fill the reflective area. Fig. 1 is only a view showing that the reflective area of the element can generate diffuse reflection on incident light, and does not relate to the specific dynamic characteristics and the modification of the reflective surface element.

To further illustrate how the reflective surface elements produce diffuse reflection, FIG. 2 illustrates design data for pitch and azimuth angles of the reflective surface elements, with a computer program randomly selecting pitch angles within 0-20 and randomly selecting azimuth angles within 0-360. Pseudo-random numbers are strings of numbers that appear random but are calculated by deterministic algorithms, so they are not truly random numbers in a strict sense. However, pseudo-random numbers are widely used because the statistical properties of pseudo-random selection (e.g., equal probability of individual numbers or statistical independence of successive numbers) are generally sufficient to meet the requirements of practical use, and unlike true random numbers, pseudo-random numbers are easily computer-generated. In fig. 2, pitch and azimuth have 10×10 data each, and a pair of data corresponding to the position determine the orientation of a reflection surface element. The data in the list of pitch and azimuth angles are also shown in fig. 2 in polar coordinates, from which it can be seen visually that the angles of the reflective surface elements are substantially uniformly and randomly distributed over a certain area. It is easily foreseen that the reflective surface element may reflect incident light to a specific area in a substantially diffuse reflection. In particular, a significant increase in the amount of angular data will result in a more uniform and random diffuse reflection visual effect.

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

{(0，2，4，6，8，10，12，14，16，18)；

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

the two sets contain regular angle data, but can still form random angle distribution of different positions (shown in a pitch angle and azimuth angle data table in fig. 3) by a random selection mode, so that the reflection area has diffuse reflection property. In fig. 3, pitch and azimuth have 10×10 data each, and a pair of data corresponding to the position determine the orientation of a reflection surface element. The data in the list of pitch and azimuth angles are also shown in fig. 3 in polar coordinates, from which it can be seen visually that the angles of the reflective surface elements are substantially uniformly and randomly distributed over a certain area. When the elemental data in the set Ω is greatly increased, it is easily foreseen that in the polar distribution diagram in fig. 3, the data points will become dense in the axial and tangential directions, essentially covering the designed set of viewing angles.

In particular, the observation angle set Ω 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 angle omega i of the incident light is along the z-axis direction, the elements of the set omega v and the set omega s are related with omega i through the law of geometric reflection, and the set omega v is the same as the angle set omega r of the reflected light.

And modifying the specific reflection surface element of the diffuse reflection area according to the animation frame forming the dynamic characteristic, thereby generating the reflection characteristic of local difference. Setting the incident ray angle ωi to be along the z-axis direction, fig. 4 and 5 provide two examples illustrating how the reflective surface element to be modified is determined.

FIG. 4 is an embodiment of determining reflective surface elements to be modified based on an animation frame. 7 is an animated frame describing the change characteristics, which frame is defined as being observed in the pitch = 0 °, azimuth = 0 °.71 is the pattern area of the animated frame and 72 is the background area of the animated frame. The pattern region 71 has an optical contrast that is visible to the human eye with the background region 72. 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 an arbitrary point Pv (also referred to as an arbitrary pixel point) on the pattern area 71 as an example, a corresponding point of Pv is determined in the reflection area 21. In the reflection region 21, a reflection surface element having a pitch angle=0° or a deviation from it of less than Δω is found in the range of Δp with Pv as a center point. In the case of small pitch angles, the difference in azimuth angle becomes less important, and therefore consideration of azimuth angle is not given here. By appropriate control of the magnitudes of Δp and Δω, the reflective surface element to be modified can always be found in the reflective region 21. For example, the projection of the reflective surface element on the xy plane is square, the side length thereof is 15 μm, Δp=30μm, Δω=1°, a point (0.4 °,75.2 °) can be found in the reflective region 21 at the lower right side of the Pv point, and the modification of the reflective surface element corresponding to 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 from an animation frame. In the animation frame 8, 81 is a pattern region of the animation frame, and 82 is a background region of the animation frame. The pattern region 81 and the background region 82 have an optical contrast that is visible to the human eye. The pattern region 81 has a change in position with respect to the above-described pattern region 71, 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 21 corresponding to the animation frame 8 on the diffuse reflection area is at least not smaller than the area size of the animation frame 8, so that the visual information of the animation frame 8 can be completely presented. Taking an arbitrary point Pw (also referred to as an arbitrary pixel point) on the pattern area 81 as an example, a corresponding point Pw is determined in the reflection area 21. In the reflection region 21, a reflection surface element having the same angle as that specified by the angle (pitch angle=10°, azimuth angle=90°) or a deviation from the angle of Δω is found within the range of Δp with Pw as the center point. By properly controlling the magnitudes of Δp and Δω, it is always possible to find the reflective surface element to be modified in the reflective area 21, for example, the projection of the reflective surface element on the xy plane is square, the side length thereof is 15 μm, Δp=30μm, Δω=1°, the point (10.1 °,92.2 °), (9.8 °,89.7 °) can be found in the vicinity of the Pv point in the reflective area 21, and modification of the reflective surface element corresponding to each of the two points can produce the expected visual contrast at the Pw point of the animation frame 8.

The modification of the reflective surface elements can take a variety of forms. The reflective surface elements 31 of the diffusely reflective region 2 in fig. 6 are modified in a specific manner, either locally or globally, so as to produce a different reflection characteristic than the reflective surface elements 32. 9 is an example of modification.

Wherein:

91 denotes modification of the reflective surface element by recessing the modified region (the modified region being a part or an entirety of the reflective surface element) around the periphery (the periphery may be, for example, the reflective surface element), the depth of the recessing being selected within the range of 0.5 μm to 3 μm and being related to the width of the modified region. At the same time, the modification of the reflective surface element may be to flatten the modified region so that the modified region reflects incident light only to a specific one of the opposite directions, and at other viewing angles, the modified region provides no or little reflected light, thereby producing a darker or darker visual perception than the other regions.

92 indicates that the modification of the reflective surface element may add a secondary structure in the modified region (the modified region being a part or whole of the reflective surface element) which has a characteristic dimension which is significantly smaller than the size of the reflective surface element and which may thus be spread over the surface of the reflective surface element in the direction of the reflective surface element. The secondary structure has a lateral characteristic dimension of 0.2 μm to 5 μm and can diffract or absorb visible light. The absorption effect can absorb incident light of a specific frequency set through a grating structure with a sub-wavelength scale by the principle of surface plasmon resonance absorption, so that the color of reflected light is changed, and the original reflection direction is maintained. Typically, when the depth of the sub-wavelength structure is relatively deep, such as 300nm to 700nm, efficient absorption can occur over a broader set of frequencies, thereby significantly reducing the brightness of the reflected light in that direction, i.e., the sub-wavelength structure becomes an optically absorptive or optically black structure.

93 indicates that the modified reflective surface element may be integrally provided with said secondary structure prior to modification, while producing a uniform reflected light distribution within the set of viewing angles qv and providing specific color or brightness characteristics. Therefore, the modification of the reflection surface element can smooth the modified area (the modified area is a part or a whole of the reflection surface element), namely, the secondary structure of the area to be modified is removed, so that the mirror reflection with higher reflectivity is generated on the whole visible light wave band.

94 are patterns that produce sufficient contrast, the surface of the reflective region or the surface opposite the surface of the reflective region may be plated or coated. This includes reflection enhancing coatings (especially metallization layers), reflection enhancing coatings, reflective ink layers, absorbing ink layers, high refractive index material coatings, and high refractive index material coatings. The reflection-enhancing coating, coating or reflective ink layer preferably has a color shift effect, i.e. a change in hue of the color at different viewing angles, e.g. using Fabry-Perot interference structures, e.g. Cr (5 nm)/MgF ₂ (500 nm)/Al (50 nm) structure. Alternatively, the reflective regions and reflective surface elements may also be imprinted in the reflective ink layer or the absorbing ink layer.

The modification to the reflective surface element may be a plating or coating thickness of the modified region (the modified region being part or whole of the reflective surface element) that is different from the unmodified region. For example, there is a reflective plating, coating, or ink on the modified areas, while there is no reflective plating, coating, or ink on the unmodified areas; there is no reflective coating, coating or ink in the modified areas, while there is a reflective coating, coating or ink in the unmodified areas.

The modification of the reflective surface element indicated at 95 may be to adjust the angle of the modified region (the modified region being part or all of the reflective surface element) so as to reflect incident light in a direction beyond the qv. The pitch angle of the reflecting surface element is generally increased beyond a minimum set defined by the directions ωi and ωv of the incident light, i.e. the incident light is reflected beyond the set defined by ωv. The modified region provides no or little reflected light, thereby producing a darker or darker visual perception than other regions.

96 indicates that the modification of the reflective surface element may be used in a serial combination of a plurality of modification modes. For example, forming a depression lower in the modified region (the modified region being a part or whole of the reflective surface element) than in the peripheral region, then adding a secondary structure in the depression, and finally removing the reflective coating of the secondary structure region (i.e. having a different thickness than the unmodified region); and forming a concave which is lower than the peripheral area in the modified area, and filling color ink in the concave, wherein the thickness of the concave is obviously larger than that of the ink in the unmodified area.

97 indicates that the modification of the reflective surface element can be combined in a parallel manner of a plurality of modification manners. For example, a flat depression is formed in a part of the modified region (the modified region is a part or whole of the reflective surface element), and a secondary structure is added in another part of the modified region along the orientation of the reflective surface element. The modification of the reflecting surface element can be the re-combination of the serial combination mode and the parallel combination mode of the modification mode.

The modified region may be present in part or in whole of the modified reflective surface element. For an ideal planar reflective surface element, the modified region would be equal to the reflective surface element, while for a curved reflective surface element, the modified region would be present locally to the reflective surface element. The width of the modified region is 0.5 μm to 30. Mu.m, preferably 2 μm to 10. Mu.m. The modified region has one or a combination of different reflection colors, different reflection brightness and different reflection texture than the unmodified region.

Reflective surface element 31 and reflective surface element 32 in fig. 6 reflect incident light 4 in directions 51 and 52, respectively. Wherein the reflected light of the modified reflective surface element 31 generates a pattern of animation frames, i.e. the modified reflective surface elements are presented together as a pattern of animation frames; the reflected light of the unmodified reflective bins 32 create the background of the animation frame, i.e., the unmodified reflective bins collectively appear as the background of the animation frame. The pattern area has different optical contrast than the background area, and can be one or a combination of different colors, different brightness and different textures which are visible to human eyes.

Fig. 7 shows a schematic representation of a banknote 10, the banknote 10 having an optical security element according to the invention, which is embedded within the banknote 10 in the form of a window security thread 101. In addition, the optical anti-counterfeiting element can be used in a labeling mode 102, and an opening area 103 can be formed on the banknote base material, so that light transmission observation is facilitated. It will be appreciated that the invention is not limited to security threads and banknotes but may be used in a variety of security products, for example in labels on goods and packaging, or in security documents, identity cards, passports, credit cards, health cards and the like. In banknotes and similar documents, in addition to security threads and labels, for example, wider security strips or transfer elements can be used.

The embodiment of the invention provides a storage medium, and a program is stored on the storage medium, and when the program is executed by a processor, the design method for learning the anti-counterfeiting element according to any embodiment of the invention is realized.

The embodiment of the invention provides a processor, which is used for running a program, wherein the program runs to execute the design method for learning the anti-counterfeiting element according to any embodiment of the invention.

The embodiment of the invention provides equipment, which comprises a processor, a memory and a program stored in the memory and capable of running on the processor, wherein the design method for the anti-counterfeiting element according to any embodiment of the invention is realized when the processor executes the program.

The present application also provides a computer program product adapted to perform a program initialized with the steps of the design method for a security element according to any of the embodiments of the present invention when executed on a data processing device.

It will be appreciated by those skilled in the art that embodiments of the present application may be provided as a method, system, or 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, and the like) 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 application. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows 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 a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

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

The memory may include volatile memory in a computer-readable medium, random Access Memory (RAM) and/or nonvolatile memory, etc., such as Read Only Memory (ROM) or flash RAM. Memory is an example of a computer-readable medium.

Computer readable media, including both non-transitory and non-transitory, removable and non-removable media, may implement information storage by any method or technology. The information may be computer readable instructions, data structures, modules of a program, or other data. Examples of storage media for a computer 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 Discs (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices, or any other non-transmission medium, which can be used to store information that can be accessed by a computing device. Computer-readable media, as defined herein, does not include transitory computer-readable media (transmission media), such as modulated data signals and carrier waves.

It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article or apparatus that comprises an element.

The foregoing is merely exemplary of the present application and is not intended to limit the present application. Various modifications and changes may be made to the present application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc. which are within the spirit and principles of the present application are intended to be included within the scope of the claims of the present application.

Claims

1. An optical security element, characterized in that it is capable of presenting a dynamic characteristic pre-designed to be a reproduction of a set of animated frames visible at a set of preset viewing angles Ω, said animated frames comprising a pattern area and a background area forming an optical contrast with said pattern area;

the optical anti-counterfeiting element is provided with a diffuse reflection area, and the diffuse reflection area can reflect incident light to at least the range of the preset observation angle set omega v;

the diffuse reflection area comprises a plurality of reflection surface elements, the plurality of reflection surface elements comprise a modified reflection surface element and an unmodified reflection surface element which are modified wholly or partially, the modified reflection surface element and the unmodified reflection surface element have different reflection characteristics, and the modified reflection surface element corresponds to the pattern area;

The modified reflective surface elements collectively present a pattern of the dynamic feature and the unmodified reflective surface elements collectively present a background of the dynamic feature when the diffusely reflective region is illuminated by the incident light, wherein,

the modified reflection surface element is formed by modifying a reflection surface element corresponding to the pattern region of each animation frame based on an observation angle of each animation frame of the group of animation frames visible at a preset observation angle set Ω, and includes:

pixelating each animation frame of the set of animation frames;

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

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

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

searching a reflection surface element corresponding to a second azimuth angle and a second pitch angle matched with 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 a pattern area in the animation frame, so as to determine the reflection surface element corresponding to the pattern area of the animation frame in the diffuse reflection area; and

And modifying the reflection surface elements which are determined in the diffuse reflection area and correspond to the pattern area of the animation frame.

2. The optical security element of claim 1 wherein the angles of the reflective elements in the plurality of reflective elements are randomly selected within a predetermined set of angles Ω, wherein the elements within the predetermined set of viewing angles Ω, the elements of the predetermined set of angles Ω, the angle of the incident light are related by a law of collective reflection.

3. An optical security element as claimed in claim 2 wherein the angle of a reflective element of the plurality of reflective elements is determined by the tilt angle and azimuth angle of the reflective element, the tilt angle being from 0 to 20 ° and/or the azimuth angle being from 0 to 360 °.

4. The optical security element of claim 2 wherein,

the angles of the reflecting surface elements in the plurality of reflecting surface elements are obtained by randomly selecting the element in the preset angle set omega s with equal probability; and/or

The angles of the reflecting surface elements in the plurality of reflecting surface elements are randomly selected from the preset angle set omega by using a pseudo-random number generating program.

5. An optical security element as claimed in claim 1 wherein the reflective surface elements of the plurality of reflective surface elements have a lateral dimension of from 3 μm to 100 μm.

6. An optical security element as claimed in claim 5 wherein the reflective surface elements of the plurality of reflective surface elements have a lateral dimension of from 10 μm to 30 μm.

7. The optical security element of claim 1, wherein the locating of the reflective surface element corresponding to the second azimuth and the second pitch matched to the first azimuth and the first pitch of the animated frame at the location of the diffuse reflective area corresponding to the pixel of the pattern area in the animated frame comprises:

and searching a reflection surface element corresponding to a second azimuth angle of which the angle difference between the first azimuth angles is in a first preset angle difference range and a second pitch angle of which the angle difference between one half of the first pitch angle is in a second preset angle difference range in a preset distance range of the diffuse reflection region corresponding to the position of the pixel of the pattern region in the animation frame.

8. The optical security element of claim 7 wherein,

the preset distance range indicates that the distance between the preset distance range and the position of the pixel of the pattern area in the animation frame is less than 100 mu m; and/or

The first preset angle difference range means that the angle difference between the first preset angle difference range and the first azimuth angle is smaller than 3 degrees; and/or

The second preset angle difference range means that the angle difference between the second preset angle difference range and the first pitch angle is smaller than 3 degrees.

9. The optical security element of claim 8 wherein,

the preset distance range indicates that the distance between the preset distance range and the position of the pixel of the pattern area in the animation frame is less than 50 mu m; and/or

The first preset angle difference range means that the angle difference between the first preset angle difference range and the first azimuth angle is smaller than 0.5 degrees; and/or

The second preset angle difference range means that the angle difference between the second preset angle difference range and the first pitch angle is smaller than 0.5 degrees.

10. An optical security element as claimed in claim 1 wherein the reflective surface elements of the plurality of reflective surface elements are planar or curved.

11. The optical security element of claim 1 wherein,

at least a portion of the unmodified reflective surface element is smooth or has a secondary structure; and/or

At least part of the diffuse reflection area is provided with a plating or coating.

12. The optical security element of claim 1 wherein the modified reflective surface element is modified in whole or in part by one or more of the following:

Adding a secondary structure to the modified reflective surface element;

smoothing the modified reflective surface element;

flattening the modified reflective surface element;

providing the modified reflective surface element with a protrusion or depression compared to the unmodified reflective surface element;

adjusting the angle of the modified reflecting surface element so that the incident light is reflected to a range beyond the preset observation angle set Ω; or alternatively

The thickness of the plating or coating of the modified reflective surface element is adjusted to be different from the unmodified reflective surface element.

13. An optical security element as claimed in claim 12 wherein, in the event that the modified reflective surface element is modified by two or more of the plurality of means, the two or more means are present in parallel and/or in series combination.

14. An optical security element as claimed in any one of claims 11 to 13 wherein the secondary structure has a lateral feature size of 0.2 μm to 5 μm.

15. An optical security element as claimed in claim 1 wherein the width of the modified region of the modified reflective surface element is from 0.5 μm to 30 μm.

16. An optical security element as claimed in claim 15 wherein the width of the modified region of the modified reflective surface element is from 2 μm to 10 μm.

17. The optical security element of claim 1 wherein the different reflective characteristics are one or a combination of different reflective colors, different reflective brightnesses, or different reflective textures of the modified reflective surface element and the unmodified reflective surface element upon illumination by the incident light.

18. A method of designing an optical security element, the method comprising:

designing an dynamic characteristic, wherein the dynamic characteristic is the reproduction of a group of animation frames visible at a preset observation angle set omega v, and the animation frames comprise pattern areas and background areas forming optical contrast with the pattern areas;

a diffuse reflection area designed for the optical security element, the diffuse reflection area being capable of reflecting incident light into at least the range of the set of preset viewing angles Ω, wherein the diffuse reflection area comprises a plurality of reflective surface elements;

modifying a reflective surface element corresponding to the pattern region of each animation frame based on an observation angle of each animation frame of the set of animation frames to form a modified reflective surface element such that the modified reflective surface element has different reflective characteristics than an unmodified reflective surface element,

the retouching of the reflective surface element corresponding to the pattern region of each animation frame to form a retouched reflective surface element comprises:

pixelating each animation frame of the set of animation frames;

19. The method of claim 18, wherein the angles of the reflective surface elements of the plurality of reflective surface elements are randomly selected from a set of predetermined angles Ω, wherein the elements of the set of predetermined angles Ω, and the angle of the incident light are related by a set law of reflection.

20. The method of claim 19, wherein the angle of a reflective surface element of the plurality of reflective surface elements is determined by the tilt angle and the azimuth angle of the reflective surface element, the tilt angle being 0 to 20 ° and/or the azimuth angle being 0 to 360 °.

21. The method of claim 19, wherein the angles of the reflective surface elements in the plurality of reflective surface elements are randomly selected within a predetermined set of angles Ω, comprising:

obtaining angles of reflecting surface elements in the plurality of reflecting surface elements by randomly selecting the element in the preset angle set omega s at equal probability; and/or

The angles of the reflective surface elements of the plurality of reflective surface elements are randomly selected from within the preset angle set Ω by using a pseudo-random number generation program.

22. The method of claim 18, wherein a lateral dimension of a reflective element of the plurality of reflective elements is 3 μιη to 100 μιη.

23. The method of claim 22, wherein a lateral dimension of a reflective element in the plurality of reflective elements is 10 μιη to 30 μιη.

24. The method of claim 18, wherein a reflective surface element of the plurality of reflective surface elements is planar or curved.

25. The method of claim 18, wherein the method further comprises:

designing at least a portion of the unmodified reflective surface element to be smooth or with a secondary structure; and/or

At least part of the diffuse reflection area is designed to be provided with a plating or coating.

26. The method of claim 18, wherein finding a reflection bin corresponding to a second azimuth and a second pitch that match a first azimuth and a first pitch of the animation frame at a location of the diffuse reflection region corresponding to a pixel of a pattern region in the animation frame comprises:

27. The method of claim 26, wherein the step of determining the position of the probe is performed,

28. The method of claim 27, wherein the step of determining the position of the probe is performed,

29. The method of claim 18, wherein retouching the reflective surface element corresponding to the pattern region of each animation frame to form a retouched reflective surface element comprises:

adding a secondary structure to the modified reflective surface element;

smoothing the modified reflective surface element;

Flattening the modified reflective surface element;

30. The method of claim 18, wherein the step of providing the first information comprises,

the dynamic characteristics are one or the combination of translation, rotation, scaling, deformation, invisibility and yin-yang conversion; and/or

The optical contrast is one or a combination of different colors, different brightness and different textures which are visible to human eyes.

31. The method of claim 18, wherein the width of the modified region of the modified reflective surface element is from 0.5 μm to 30 μm.

32. The method of claim 31, wherein the width of the modified region of the modified reflective surface element is from 2 μm to 10 μm.

33. A security product using the optical security element of any one of claims 1 to 17.

34. A data carrier, characterized in that it has an optical security element according to any one of claims 1 to 17 or has a security product according to claim 33.