CN115230364A

CN115230364A - Optical anti-counterfeiting element and design method thereof, anti-counterfeiting product and data carrier

Info

Publication number: CN115230364A
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: 2022-10-25
Anticipated expiration: 2041-04-25
Also published as: WO2022227740A1; CN115230364B; EP4331858A1

Abstract

The embodiment of the invention provides an optical anti-counterfeiting element and a design method thereof, an anti-counterfeiting product and a data carrier, and belongs to the field of anti-counterfeiting. 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 a preset observation angle set omega v; the diffuse reflective area comprises a plurality of reflective surface elements including a wholly or partially modified reflective surface element and an unmodified reflective surface element, the modified reflective surface element and the unmodified reflective surface element having different reflective characteristics, wherein the modified reflective surface element corresponds to a pattern area; when the diffuse reflection area is illuminated by the incident light, the modified reflection surface elements collectively present a pattern of dynamic features, and the unmodified reflection surface elements collectively present a background of dynamic features. The optical anti-counterfeiting element is simple in manufacturing process and can flexibly realize dynamic characteristics such as color and/or light-dark contrast.

Description

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

Technical Field

The invention 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

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-value-added products such as bank notes, financial bills and the like, and a very good effect is achieved.

At present, an attractive technology is to combine a microstructure determined by plate making with an optically variable layer, as disclosed in chinese patents CN102712207a and CN107995894A, and modulate the brightness distribution of reflected light by a pre-designed micro-reflective surface, thereby realizing an animated effect, and can realize the combination of color change and animated effect by overlapping interference coatings. This can often produce a variety of motion effects in patterns such as lines, circles, curves or text, and can produce a three-dimensional perspective. However, in most cases, the color and the hue of the pattern and the background can only be the same, and the contrast relationship between the light and the shade is basically single, so that the dynamic characteristics of various colors or any light and shade relationship are difficult to realize.

Display figures with three-dimensional depth effects can also be produced by a moire magnification construction based on microlenses and micro patterns, as described for example in document WO 2005/052650 A2. Here, a periodic presentation composed of many small micropatterns is magnified with a grid composed of microlenses having similar but not identical periods. In this way, a stereoscopic impression can be produced that is clearly in front of or behind the actual surface, or so-called orthogonal parallax motion can be produced. However, such a moir e magnification configuration is disadvantageous in that it is complicated to manufacture, requires two embossing steps for the microlenses and the micropattern, and requires precise alignment between the two steps.

Finally, as described for example in WO2014/108303A1, magnetically aligned reflective pigments are aligned with correspondingly shaped magnets, thereby creating a bright (especially ring-shaped) dynamic effect that may include a certain 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 anti-counterfeiting element with simple manufacturing process and flexible dynamic characteristics of color and/or contrast.

Disclosure of Invention

The embodiment of the invention aims to provide an optical anti-counterfeiting element, a design method thereof, an anti-counterfeiting product and a data carrier, wherein the optical anti-counterfeiting element is simple in manufacturing process and can flexibly realize dynamic characteristics such as color and/or light and shade contrast.

In order to achieve the above object, an embodiment of the present invention provides an optical security element, where the optical security element is capable of presenting dynamic features, where the dynamic features are pre-designed to be a reproduction of a set of animation frames visible at a preset viewing angle set Ω v, and each animation frame includes a pattern area and a background area forming 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 reflective area comprises a plurality of reflective surface elements including a modified reflective surface element that is wholly or partially modified and an unmodified reflective surface element that has different reflective characteristics, wherein the modified reflective surface element corresponds to the pattern area; when the diffuse reflection area is illuminated by the incident light, the modified reflective surface elements collectively appear as a pattern of the dynamic features and the unmodified reflective surface elements collectively appear as a background of the dynamic features.

Optionally, angles of the reflection surface elements in the plurality of reflection surface elements are randomly selected within a preset angle set Ω s, wherein elements in the preset observation angle set Ω v, elements in the preset angle set Ω s, and angles of the incident light are associated through a set reflection law.

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

Optionally, the angles of the reflection surface elements in the plurality of reflection surface elements are obtained by randomly selecting the elements in the preset angle set Ω s according to an 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 set Ω s by using a pseudo random number generation procedure.

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

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

Optionally, at least a portion of the unmodified reflective surface elements are smooth or secondary structured; and or at least part of the diffuse reflection area is provided with a coating or a coating.

Optionally, the modified reflective surface elements are 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; arranging the modified reflective surface elements to have a protrusion or depression as compared to an unmodified reflective surface element; adjusting the angle of the modified reflection surface element to enable the incident light to be reflected to a range beyond the preset observation angle set omega v; or the thickness of the plating or coating of the modified reflective surface elements may be adjusted to be different than the unmodified reflective surface elements.

Optionally, where the modified reflective surface elements are modified in two or more of the plurality of ways, the two or more ways exist in a parallel combination and/or a serial combination.

Optionally, the secondary structure has a lateral feature size of 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 that the modified reflection surface element and the unmodified reflection surface element have one or a combination of different reflection colors, different reflection brightnesses, or different reflection textures when the incident light is irradiated.

Correspondingly, the embodiment of the invention also provides a design method for the chemical anti-counterfeiting element, which comprises the following steps: designing a dynamic characteristic which is the reproduction of a group of animation frames visible at a preset observation angle set omega v, wherein each animation frame comprises a pattern area and a background area forming optical contrast with the pattern area; designing a diffuse reflection area for the optical security element, the diffuse reflection area being capable of reflecting incident light to at least the range of the preset set of viewing angles Ω v, wherein the diffuse reflection area comprises a plurality of reflection surface elements; based on the viewing angle of each animation frame of the group of animation frames, modifying the reflective surface elements corresponding to the pattern regions of each animation frame to form modified reflective surface elements, so that the modified reflective surface elements and the non-modified reflective surface elements have different reflective characteristics, and when the diffuse reflective regions are illuminated by the incident light, the modified reflective surface elements collectively appear as the pattern of the kinetic features, and the non-modified reflective surface elements collectively appear as the background of the kinetic features.

Optionally, angles of the reflection surface elements in the plurality of reflection surface elements are randomly selected within a preset set Ω s, wherein elements in the preset observation angle set Ω v, elements in the preset set Ω s, and angles of the incident light are associated through a set reflection law.

Optionally, the randomly selecting the angle of the reflection surface element in the plurality of reflection surface elements within a preset angle set Ω s includes: obtaining the angles of the reflecting surface elements in the plurality of reflecting surface elements by randomly selecting the elements in the preset angle set omega s at equal probability; and/or randomly selecting an angle of a reflective surface element of the plurality of reflective surface elements from within the preset angle set Ω s by using a pseudo random number generation program.

Optionally, the method further includes: designing at least a portion of the unmodified reflective surface elements to be smooth or with secondary structures; and or at least some of the diffusely reflective regions are designed with a coating or layer.

Optionally, modifying the reflective surface element corresponding to the pattern region of each animation frame to form a modified reflective 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, the first azimuth angle and the first pitch angle being determined according to an 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; for each animation frame of the set of animation frames, performing the steps of: searching a reflection surface element corresponding to a second azimuth angle and a second pitch angle which are matched with 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, of the diffuse reflection area, and accordingly determining the reflection surface element corresponding to the pattern area of the animation frame in the diffuse reflection area; and modifying the reflection surface element corresponding to the pattern area of the animation frame, which is determined in the diffuse reflection area.

Optionally, finding a reflection surface element corresponding to a second azimuth angle and a second pitch angle that are 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 the pattern area in the animation frame includes: and searching a reflection surface element corresponding to a second azimuth angle of the angle difference between the first azimuth angle and the second pitch angle of the half of the first pitch angle within a second preset angle difference range within a preset distance range of the position, corresponding to the pixel of the pattern area in the animation frame, of the diffuse reflection area.

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

Optionally, modifying the reflective surface element corresponding to the pattern region of each animation frame to form a modified reflective 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; arranging the modified reflective surface elements to have a protrusion or a depression compared to the non-modified reflective surface elements; adjusting the angle of the modified reflection surface element to enable the incident light to be reflected to a range beyond the preset observation angle set omega v; or the thickness of the plating or coating of the modified reflective surface element is adjusted to be different from the unmodified reflective surface element.

Optionally, the dynamic characteristics are one or a combination of translation, rotation, scaling, deformation, hiding and yin-yang conversion; and/or the optical contrast is one or a combination of different colors, different brightness, 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, and the data carrier 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 a simple manufacturing process, can flexibly realize dynamic characteristics such as color and/or light-dark contrast, and the like, can present various multicolor dynamic characteristics in a macroscopic view, and does not have directly recognizable arrangement rules in a microscopic view, so that the counterfeiting difficulty is enhanced in multiple dimensions such as microstructure design, a manufacturing process and the like.

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

Drawings

The accompanying drawings, which are included to provide a further understanding of the 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 the embodiments of the invention without limiting 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 view of diffuse reflection of incident light by a diffuse reflection area of an optical anti-counterfeiting element;

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

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

FIG. 4 is one embodiment of determining a reflective surface element to be modified based on an animation frame;

FIG. 5 is another embodiment for determining a reflective surface element to be modified based on an animation frame;

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

figure 7 is a schematic representation of the use of an optical security element on a banknote.

Detailed Description

The following describes in detail embodiments of the present invention with reference to the drawings. It should be understood that the detailed description and specific examples, while indicating embodiments of the invention, are given by way of illustration and explanation only, not limitation.

The embodiment of the invention provides an optical anti-counterfeiting element, which can present dynamic characteristics, wherein the dynamic characteristics are designed in advance as a group of reappearance of animation frames visible at a preset observation angle set omega v, and each animation frame comprises a pattern area and a background area forming 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 reflective area comprises a plurality of reflective surface elements including a wholly or partially modified reflective surface element and an unmodified reflective surface element, the modified reflective surface element and the unmodified reflective surface element having different reflective characteristics, wherein the modified reflective surface element corresponds to the pattern area; when the diffuse reflection area is illuminated by the incident light, the modified reflection surface elements collectively present a pattern of the dynamic characteristics, the unmodified reflection surface elements collectively present a background of the dynamic characteristics, that is, the modified reflection surface elements collectively reproduce the pattern of the dynamic characteristics, and the unmodified reflection surface elements collectively reproduce the background of the dynamic characteristics.

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

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

The group of animation frames visible at the preset observation angle set Ω v described 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 substantially refer to dynamic characteristics appearing when the observation angle is changed. In principle, the viewing angle may be the angle of one or more of the three elements, light source (i.e. incident light), element and viewer. For example, under the condition that the positions of the illumination light source and human eyes are not changed, the optical anti-counterfeiting element or the article with the optical anti-counterfeiting element is held in the hand, and the designed dynamic characteristic can be seen by shaking the element back and forth or left and right, namely changing the angle of the optical anti-counterfeiting element. For simplicity of description, the viewing direction, and hence the viewing angle, is defined by the line connecting the eye of the viewer and the point of view. It should be noted that this definition does not materially affect or limit any of the concerns of the embodiments of the present invention. The observation angle is a three-dimensional space parameter, so that the observation angle needs to be decomposed into at least two angles for accurate description. For example, pitch and azimuth angles can be used together, and the angles between the observation direction and three coordinate axes of x, y and z can also be used together. In the xyz coordinate defined in the embodiment of the present invention, the xy plane is a plane where the optical anti-counterfeiting element is located, the x axis may be a longitudinal direction of the optical anti-counterfeiting element, the y axis may be a transverse direction of the optical anti-counterfeiting element, and the z axis may be an axis perpendicular to the optical anti-counterfeiting element.

The pattern of the animation frame may be designed as letters, numbers, characters, symbols or geometric shapes (especially circles, ovals, triangles, rectangles, hexagons or stars, etc.). The above dynamic characteristics generally refer to any one of translation, rotation, scaling, deformation, hiding, yin-yang transformation, and the like of a design pattern presented by an element and directly visible to human eyes, and may also be any combination of these dynamic characteristics. The translation may be designed to translate the design in a particular direction, or may be designed to translate in multiple directions, the directions of translation being associated with the viewing direction. One commonly used combination feature is that the position of the design animation frame pattern changes, and simultaneously, the shape of the design animation frame pattern changes, such as a circle changes into a square. The dynamic characteristics can have orthogonal parallax motion behaviors of the patterns, namely the motion direction of the patterns is always vertical to the change of the observation direction, and the attention of an observer is further attracted through an anti-intuitive phenomenon. The motion of the animated frame pattern can create a stereoscopic impression floating above or below the plane of the element by the principle of binocular horizontal parallax. The pattern may also comprise a plurality of sub-patterns exhibiting the same or different motion behaviour and/or the same or different floating height or floating depth. In particular, the pattern may comprise at least a first curve and a second curve, which curves, when viewed from a first or second viewing direction, respectively, appear as a first or second target curve, respectively, located at a central position of the first or second area. The two curves preferably move in different (preferably opposite) directions when the security element is tilted, thereby creating a particularly dynamic appearance. It will be appreciated that in the same way the pattern of the security element may also comprise more than two curves, which curves may move in the same or different directions when the security element is tilted. For example, curves in the form of alphanumeric character strings may alternately exhibit different movement behaviors, for example alternately floating above or below the plane of the planar pattern area, and moving according to their floating height when tilted. Specific principles of various dynamic characteristics can be referred to in the prior patent texts CN102712207A, CN107995894A, WO 2005/052650 A2 and the like. The terms "pattern" and "pattern area" may be substituted for each other in the embodiments of the present invention.

The dynamic characteristics can be represented by a group of pictures generated by computer software, such as mathematical computation software, pattern processing software and the like during specific design. For example, using a bitmap in the format bmp, different colored design patterns and a common background of the patterns are represented by gray values of 0-255. Each picture corresponds to visual information presented to human eyes under a specific observation angle, and is called a frame of animation of designed dynamic characteristics.

The observation angle set Ω v means that all preset dynamic characteristics can be seen when the observation angle of human eyes changes in the set. The optical security element may reflect illumination beyond the collection, but such reflected light may not be associated with the designed animation feature, and may also provide darker or black visual information for the animated feature. The set of viewing angles Ω v may be described in terms of azimuth and elevation angles, for example, the azimuth angle may be designed to be 0-360 °, the elevation angle may be 0-35 ° or 10-50 °, etc., i.e. the dynamic features may be seen in the area where the human eye is in the cone shape. The setting of the angle parameter depends on the purpose of the designer, the owned lighting environment of the observer, the observation habit, and the like.

The reflective surface elements of the diffuse reflective area may be in particular flat planes, each reflective surface element being characterized by an inclination with respect to the plane in which the pattern area of said dynamic features is located and by a rotation angle with respect to the x-axis direction, so that the orientation of the reflective surface element (which may also be referred to as the angle of the reflective surface element) may be determined using the pitch angle and the azimuth angle. Of course, other parameters may be used to orient the bins, particularly parameters that are orthogonal to one another, such as two orthogonal components of the direction of the reflective bins. Optionally, the reflective surface element of the diffuse reflection area may be a curved surface. Mathematically, a curved surface can continue to be broken down into a number of bins that are closer to a plane and smaller in area, with no essential difference in the specific design of the curved surface from a flat plane. To produce sufficiently fine patterns and continuously varying dynamic features, the size of the reflective surface elements is preferably smaller than the human eye's ability to recognize, which is typically about 100 μm at photopic distances, which improves the resolution at closer distances. Therefore, the bin size is preferably not larger than 100 μm. On the other hand, too small a bin may produce significant diffraction of light, affecting the color stability of the dynamic characteristics. Reflective surface elements having lateral dimensions of 3 μm to 100 μm can produce sufficiently fine features without significant diffractive iridescence, and further preferably have lateral dimensions of 10 μm to 30 μm. The projection of the reflective surface elements onto the plane of the dynamic pattern is typically chosen to be rectangular, but may be any pattern that facilitates the tiling of the plane, such as triangular, hexagonal, irregular, etc.

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

The main function of the reflective surface elements forming the diffusely reflective regions is to produce a uniform reflected light at least over a predetermined set of viewing angles Ω v, similar to the diffuse reflective visual impression produced by ordinary office paper. For this purpose, the orientation of the reflection surface elements varies or is selected irregularly within a predetermined set of angles Ω s, in particular randomly or pseudo-randomly (i.e. can be selected randomly within a predetermined set Ω s). Pseudo-random numbers are strings of numbers that appear random but are computed by deterministic algorithms, and thus, in the strict sense, they are not truly random numbers. However, pseudo-random numbers are widely used because pseudo-randomly chosen statistical properties (e.g., equal probability of individual digits or statistical independence of successive digits) are generally sufficient for practical purposes, and unlike true random numbers, pseudo-random numbers are easy to generate by computers. Specifically, the random change of the orientation of the reflection surface element within the preset angle set Ω s can be realized 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 omega v, the elements in the preset set omega s and the angle omega i of the incident light are related through a set reflection law. The angle set Ω s is chosen to reflect the incident light uniformly at least into the viewing angle set Ω v, so that Ω s covers a minimum set determined by the incident light angles ω i and Ω v together. Equivalently, a reflective region made up of multiple reflective bins reflects incident light to a set of angles Ω r, which covers the set of viewing angles Ω v, i.e., Ω v is a subset or proper subset of Ω r. Preferably, Ω s is designed as the smallest set jointly determined by the incident light angles ω i and Ω v, i.e. Ω v is the same as Ω r. For example, when the 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 geometric reflection, the azimuth angle of the element of Ω s is the same as the azimuth angle of the element of Ω v, and the pitch angle of the element is half of the pitch angle of the element of Ω v.

In order to realize the change characteristic, the diffuse reflection area needs to be modified according to each pixel point of each animation frame, so that the uniform reflected light distribution in the observation angle set Ω v is changed. The size of the diffuse reflection area is larger than the area occupied by all the animation frames when 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 where the pattern region included in a certain animation frame is located and the observed angle ω v thereof, the position Ps and the angle ω s of the reflection surface element to be modified are found, for example, the position and the angle of the reflection surface element to be modified can be found for each pixel. In principle, pv and Ps should be at the same position, and ω v, ω s and the incident light angle ω i should satisfy the reflection law of geometric optics, that is, the incident light, the reflected light, the normal of the reflection surface element are in the same plane, and the incident angle is equal to the reflection angle. Here, ω s = f (ω v, ω i) indicates that there is a quantitative relationship between the three, and a specific calculation formula can be found in a general optical textbook, for example, born' optical principle: electromagnetic theory of propagation, interference and diffraction of light. In practical designs, since the angles of the reflection bins are randomly chosen within the angle set Ω s, when Pv = Ps, the angle ω s of the reflection bin at that location may not exactly satisfy the geometric reflection law with ω v and ω i. Thus, the reflection surface element to be modified can be found over 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 selection of the position deviation Δ P and the angle deviation Δ ω is specifically determined according to the size of the reflective surface element, the resolution of human eyes on angles and sizes, and the designed dynamic characteristics, and the principle is that at least one reflective surface element to be modified can be found without generating human eye distinguishable differences from the designed pattern. The positional deviation Δ P is generally less than 100 μm, preferably less than 50 μm. The angle deviation Δ ω is defined as an angle between the normal direction of the modified reflection surface element and the normal direction of the reflection surface element corresponding to the preset observation angle of the pattern, and the angle deviation Δ ω should be less than 3 °, and preferably less than 0.5 °.

In general, with two reflecting surface elementsElevation angles are respectively theta ₁ ，θ ₂ In azimuth angle of respectively

The angle between the normals of the two reflective surface elements can be calculated by the following equation:

each animation frame may be pixilated upon specific execution. Alternatively, only the pattern region of each animation frame may be pixilated. The essence of pixelation is to divide the animation frame into, for example, nxM small regions, each of which may have a very small footprint, for example. 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 correspondingly, the length of each small region may be 0.5 μm to 10 μm, preferably 2 μm to 4 μm. Finding the reflective surface elements to be modified is finding the reflective surface elements corresponding to the pixels of the pattern area.

Further, a first azimuth and a first pitch angle for each animation frame may be determined, each animation frame corresponding to a particular viewing angle, whereby the first azimuth 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 complement angle to the z-axis). And projecting the direction vector onto an xy plane to form a projection vector, wherein the included angle between the projection vector and the x axis is defined as an 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 s may consist of an azimuth angle and a pitch angle, and thus, the second azimuth angle and the second pitch angle of each reflection bin may be previously stored. The second azimuth angle and the second pitch angle of each reflecting element of the diffuse reflection area can be acquired from the database.

For each animation frame of the set of animation frames, the following steps may be performed: and searching for a reflection surface element corresponding to a second azimuth angle and a second pitch angle which are matched with 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, of the diffuse reflection area, so as to determine the reflection surface element corresponding to the pattern area of the animation frame in the diffuse reflection area. For example, the group of animation frames can be projected perpendicularly on the diffuse reflection area in proportion, so that the position of the diffuse reflection curved surface corresponding to each pixel in each animation frame can be determined. Finding a reflection bin corresponding to a second azimuth angle and a second pitch angle that match the first azimuth angle and the first pitch angle of the animation frame may comprise: and searching a reflection surface element corresponding to a second azimuth angle of the angular difference between the first azimuth angle and a second pitch angle of one half of the first pitch angle within a second preset angular difference range 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. 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 angular difference between the half of the first pitch angle is within the second predetermined angular difference range may be searched only within the predetermined distance range without considering the azimuth angle. Alternatively, when the pitch angle is below approximately 2 °, the difference in orientation due to the difference in azimuth angle may be considered insignificant, and the azimuth angle may not be considered. The preset distance range indicates that a distance between positions of the diffuse reflection area corresponding to pixels of the pattern area in the animation frame is less than 100 μm, preferably less than 50 μm. The first predetermined angular difference range is an angular difference of less than 3 °, preferably less than 0.5 °, from the first azimuth angle. Said second predetermined angular difference range is defined as an angular difference of less than 3 °, preferably less than 0.5 °, from half said first pitch angle. For a pixel of the pattern area, one or more eligible reflection surfaces may be found in the diffuse reflection area, and the one or more eligible reflection surfaces may be modified. After finding a reflective surface element in the diffuse reflective area that matches each pixel of the pattern area of the animation frame, these matching reflective surface elements form a reflective surface element that corresponds to the pattern area of the animation frame. And modifying the reflection surface element formed in the diffuse reflection area and corresponding to the pattern area of each animation frame to form a modified reflection surface element.

The modification of the reflective surface element can add a secondary structure to the modified reflective surface element, wherein the secondary structure has a characteristic dimension which is significantly smaller than that of the reflective surface element, and thus can be spread on the surface of the reflective surface element along the trend of the reflective surface element. The secondary structure has a lateral feature size of 0.2 μm to 5 μm and is diffractive or absorptive to visible light. The absorption can absorb the incident light of a specific frequency set through a grating structure with a sub-wavelength scale by the principle of surface plasmon resonance absorption, thereby changing the color of the reflected light and simultaneously keeping the original reflection direction. Generally, when the depth of the sub-wavelength structure is relatively deep, such as 300nm to 700nm, effective absorption can be generated in a wider frequency range, so that the brightness of the reflected light in the direction is significantly reduced, i.e., the sub-wavelength structure becomes an optical absorption or optical black structure.

The modified reflective surface elements may have the secondary structure as a whole before modification to provide a specific color or brightness characteristic while producing a uniform reflected light distribution within the set of viewing angles Ω v. Thus, the described modification of the reflective surface elements may smooth the reflective surface elements being modified, either locally or globally. For example, the secondary structure of the modified reflective surface element is removed, so that the secondary structure can generate mirror reflection with higher reflectivity for all visible bands. Optionally, at least a portion of the unmodified reflective surface elements may be provided smooth or with secondary structures.

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 in a particular one of the directions of reflection. At other viewing angles, the modified region provides no or only little reflected light, resulting in a darker or darker visual perception than other regions.

The modification of the reflective surface element may be adjusting the angle of the modified reflective surface element, so that the modified reflective surface element can reflect all light rays incident to the modified reflective surface element to a direction exceeding the preset viewing angle set Ω v. The pitch angle of the reflecting surface element is generally increased beyond a minimum set determined by the incident light directions ω i and Ω v, i.e., the incident light is reflected beyond the set determined by Ω v. The modified reflective surface elements provide no or only 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 reflective surface elements are modified or the surface opposite the surface on which the reflective surface elements are modified (e.g., the unmodified reflective surface elements) may have a coating or coating. This includes reflection enhancing coatings (especially metallized layers), reflection enhancing coatings, reflecting ink layers, absorbing ink layers, coatings of high refractive index materials. The reflection enhancing coating, plating or layer of reflective ink preferably has a color shifting effect, i.e. a change in hue of color at different viewing angles, for example using a fabry perot interference structure. Alternatively, the reflective regions and reflective surface elements may also be embossed in the reflective ink layer or the absorbing ink layer.

The modification of the reflecting surface element can be that a protrusion or a recess is formed on the periphery of the modified reflecting surface element compared with the unmodified area; or the reflective surface element may be modified by a coating or coating having a thickness that is different from the unmodified area. For example, reflective coatings, coatings or inks on the reflective surfaces that are modified, while reflective coatings, coatings or inks on the reflective surfaces that are not modified; or no reflective coating, coating or ink on the reflective surfaces that are modified and reflective coating, coating or ink on the reflective surfaces that are not modified.

The modification of the reflective surface element can be a combination of the above multiple modification modes in a serial mode. For example, forming a recess in the reflective surface element that is modified to be lower than the reflective surface element that is not modified, then adding a secondary structure to the recess, and finally removing the reflective coating in the secondary structure area (i.e., having a different thickness than the reflective coating of the reflective surface element that is not modified); alternatively, a depression lower than the unmodified reflective surface element is formed in the modified reflective surface element, and the depression is filled with a color ink, which is substantially thicker than the ink of the unmodified reflective surface element. The modification of the reflection surface element can be combined and used in a parallel mode of a plurality of modification modes. For example, a flat depression may be formed in one portion of the modified reflective surface element and a secondary structure may be added along the orientation of the reflective surface element in another portion of the modified reflective surface element. The modification of the reflection surface element can be a combination of the serial combination mode and the parallel combination mode of the modification modes.

The modified region may be present in part or in the entirety of the reflective surface element being modified. For an ideal planar reflective surface element, the modified area will be equal to the reflective surface element. Whereas for a curved reflective surface element, the modified region will be present locally to 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 reflecting surface element has one or a combination of different reflecting colors, different reflecting brightness and different reflecting textures compared with the non-modified reflecting surface element. Alternatively, the modified region may have one or a combination of different reflective colors, different reflective brightness, and different reflective texture compared to the unmodified region.

In the observation angle set omega v of the optical anti-counterfeiting element, the modified reflection surface elements are presented as patterns of animation frames together, and the unmodified reflection surface elements are presented as backgrounds of the animation frames together. The pattern area has a different optical contrast than the background area, and specifically may be one or a combination of different colors, different brightnesses, and different textures visible to human eyes.

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

The dynamic characteristics can be represented by a group of pictures generated by computer software, such as mathematical computation software, pattern processing software and the like during specific design. For example, using a bitmap in the format bmp, different colored design patterns and a common background of the patterns are represented by gray values of 0-255. Each picture corresponds to visual information presented to human eyes under a specific observation angle, and is called a frame of animation of designed dynamic characteristics. The specific working principle and benefits of the design method for an optical anti-counterfeiting element according to the embodiment of the present invention can refer to the description of the optical anti-counterfeiting element according to the embodiment of the present invention, and will not be described herein again.

Correspondingly, the embodiment of the invention also provides an anti-counterfeiting product using the optical anti-counterfeiting element in any embodiment of the invention. The security product may be in the form of, for example, a security thread, a security strip, a security label, or the like. Embodiments of the present invention also provide a data carrier having a security element according to any of the embodiments of the present invention or a security product according to any of the embodiments of the present invention, which can be arranged in an opaque area of the data carrier and in or above a transparent window area or through opening in the data carrier. The data carrier can be, in particular, a value document, for example a banknote (in particular a paper banknote, a polymer banknote or a film composite banknote), a stock certificate, a ticket, a check, a high-value admission ticket, but also an identification card, for example 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 attached drawings.

Fig. 1 is a schematic view of diffuse reflection action of a diffuse reflection area of an optical anti-counterfeiting element on incident light. The plane of the element 1 is defined as the xy-plane, and the diffuse reflection area 2 is formed by a plurality of reflection surface elements 3. In fig. 1, the optical security element has a substrate 6, and the diffuse reflection area 2 is located on one side of the substrate. The presence of the substrate 6 is however a requirement of the processing process, which may not be part of the optical security element itself. The substrate 6 may be part of a security product formed by the optical security element 1. Of course, the substrate can also be removed in a security product, for example a hot stamped product, the structured layer being transferred to another carrier, without the substrate 6 forming part of the security product. The substrate 6 does not form an essential component of the component 1. Incident light 4 is incident to one side of the substrate with a reflection area, and the incident light 4 forms a plurality of reflected light rays 5 in different directions through the reflection action of the diffuse reflection area 2. By controlling the size and angular distribution (defined, for example, by azimuth and elevation angles) of the reflective surface elements of the diffuse reflective area 2, a substantially uniform diffuse reflective visual effect covers a predetermined set of viewing angles Ω v of the animated feature. For simplicity of description without loss of generality, the direction of the incident light 4 is set to be the z direction, which is a direction perpendicular to the xy plane. Whereas the azimuth angle of the elements of the set Ω v is predetermined to be 0-360 ° and the pitch angle is predetermined to be 0-35 °. Accordingly, the lateral dimensions of the reflective surface elements can be controlled to be in the range of 10 μm to 15 μm, while the longitudinal height is set to be 0 to 5 μm, with the azimuthal angle randomly chosen between 0-360 °, so that the incident light 4 is reflected by the plurality of reflective surface elements to the set of angles Ω r, which can cover the set of viewing angles Ω v. Since discrete angle information is usually used in practical design, the coverage of the present invention specifically means that any element in the set Ω v can find a corresponding element close enough to it in Ω r, for example, the included angle between the two elements does not exceed 1 °. The diffuse reflection area 2 should contain enough reflective surface elements 3 to obtain a sufficiently uniform and dense reflected light, and the size of the diffuse reflection area in practical designs should be 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 reflecting surface element can be designed into an oblique wedge shape, and the projection on the xy plane can be designed into a rectangle so as to fully cover the reflecting area. Fig. 1 is merely a diagram showing that the reflective regions of the element can diffuse incident light, and does not refer to the specific dynamic characteristics and the modification of the reflective surface elements.

To further illustrate how the reflective surface elements produce diffuse reflection, FIG. 2 illustrates pitch and azimuth design data for a reflective surface element, using a computer program to randomly select a pitch angle between 0 and 20 degrees and an azimuth angle between 0 and 360 degrees. Pseudo-random numbers are strings of numbers that appear random but are computed by deterministic algorithms, and thus, in the strict sense, they are not truly random numbers. However, pseudo-random numbers are widely used because pseudo-randomly chosen statistical properties (e.g., equal probability of individual digits or statistical independence of successive digits) are generally sufficient for practical purposes, and unlike true random numbers, pseudo-random numbers are easy to generate by computers. In fig. 2, there are 10 x 10 data for each of pitch and azimuth, and a pair of data for corresponding positions determines the orientation of a reflective surface element. Fig. 2 also shows the data in the list of pitch and azimuth angles in polar coordinates, from which it can be visually seen that the reflection bin angles are distributed substantially uniformly and randomly over a certain area. It is readily envisioned that the reflective surface elements may reflect incident light to a particular area in a substantially diffuse manner. In particular, a more uniform and random diffuse reflectance visual effect will be obtained with a significant increase in the amount of angular data.

Fig. 3 illustrates another example of design data for pitch and azimuth angles for a reflective bin, where pitch angles are randomly chosen in the set {0,2,4,6,8, 10, 12, 14, 16, 18} and azimuth angles are randomly chosen in the set {0, 40, 80, 120, 160, 200, 240, 280, 320, 360}, i.e., the set of reflective bin angles Ω s is:

{(0，2，4，6，8，10，12，14，16，18)；

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

apparently, the two sets contain regular angle data, but random angle distributions (as shown in the pitch angle and azimuth angle data table in fig. 3) with different positions can still be formed by means of random selection, so that the reflection area has diffuse reflection property. In fig. 3, there are 10 x 10 data for each of pitch and azimuth, and a pair of data for corresponding positions determines the orientation of a reflective surface element. The data in the list of pitch and azimuth angles is also given in fig. 3 in polar coordinates, from which it can be visually seen that the reflection bin angles are distributed substantially uniformly and randomly over a certain area. When the elemental data in the set Ω s 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, substantially covering the designed set of viewing angles.

In particular, the set of viewing angles Ω v 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 ω i is along the z-axis direction, the set Ω v and the set Ω s are related to ω i by the geometric reflection law, and the set Ω v is the same as the angle set Ω r of the reflected light.

And modifying the specific reflecting surface element of the diffuse reflection area according to the animation frames forming the dynamic characteristics so as to generate the locally different reflection characteristics. Setting the incident ray angle ω i to be along the z-axis, fig. 4 and 5 provide two examples illustrating how the reflective surface element to be modified can be determined.

Fig. 4 is an embodiment of determining a reflective surface element to be modified from an animation frame. And 7, an animation frame describing the change characteristics, wherein the frame is defined as being observed in a direction with a pitch angle =0 ° and an 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 an arbitrary point Pv (which may be considered as an arbitrary pixel) on the pattern region 71 as an example, a corresponding point of Pv is determined in the reflection region 21. In the reflection area 21, a reflection surface element having a pitch angle =0 ° or a deviation therefrom smaller than Δ ω is sought within a range of Δ P with Pv as a center point. In the case of a small pitch angle, the difference in azimuth angle becomes less important, so that no consideration is given here to azimuth angle. By appropriate control of the magnitude of Δ P and Δ ω, the reflective surface element to be modified can always be found in the reflective region 21. For example, the reflection bin projection in the xy plane is a square with a side length of 15 μm, setting Δ P =30 μm, Δ ω =1 °, a point (0.4 °,75.2 °) can be found in the reflection area 21 to the lower right of the Pv point, and the embellishment of the corresponding reflection bin for that point can produce the expected visual contrast at the Pv point of the animation frame 7.

Fig. 5 is another embodiment for determining a reflective surface element 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 area 81 has an optical contrast visible to the human eye with the background area 82. The pattern region 81 has a positional change with respect to the pattern region 71, and the animation frame 8 is defined to be observed in a direction of a pitch angle =20 ° and an 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 an arbitrary point Pw (which may be considered as an arbitrary pixel) on the pattern region 81 as an example, a corresponding point Pw is determined in the reflective region 22. In the reflection area 2, a reflection surface element having the same angle as the reflection surface element determined by the angle (pitch angle =10 °, azimuth angle =90 °), or having an angular deviation smaller than Δ ω, is sought within a range of Δ P with Pw as a center point. By appropriately controlling the size of Δ P and Δ ω, the reflection bin to be modified can always be found in the reflection region 22, for example, the projection of the reflection bin in the xy plane is a square with a side length of 15 μm, Δ P =30 μm, Δ ω =1 °, a point (10.1 °,92.2 °) (9.8 °,89.7 °) can be found in the reflection region 2 in the vicinity of the Pv point, and the modification of the two respective reflection bins can produce the expected visual contrast at the Pw point of the animation frame 8.

The reflective surface elements can be modified in a number of ways. The reflection surface element 31 of the diffuse reflection area 2 of fig. 6 is modified in a local or overall manner in such a way that a reflection characteristic different from that of the reflection surface element 32 results. 9 is an example of a modification.

Wherein:

the modification of the reflective surface element is indicated at 91 by recessing the modified region (which is a portion or the entirety of the reflective surface element) from the perimeter (which may be, for example, the reflective surface element), the depth of the recess being selected to be within 0.5 μm to 3 μm and being related to the width of the modified region. Also, the trim of the reflective surface elements may be to flatten the modified regions so that the modified regions reflect incident light only in a particular one of the reverse directions, and at other viewing angles, the trim regions provide no or little reflected light, resulting in 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 to the modified area (the modified area being a portion or the entirety of the reflective surface element) that has a characteristic dimension that is significantly smaller than the size of the reflective surface element and thus may be spread across the reflective surface element surface along the orientation of the reflective surface element. The secondary structure has a lateral feature size of 0.2 μm to 5 μm and is diffractive or absorptive to visible light. The absorption can absorb the incident light of a specific frequency set through a grating structure with a sub-wavelength scale by the principle of surface plasmon resonance absorption, thereby changing the color of the reflected light and simultaneously keeping the original reflection direction. Generally, when the depth of the sub-wavelength 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 reflected light in that direction, i.e., the sub-wavelength structure becomes an optically absorbing or optically black structure.

93, the modified reflective surface element may be provided with the secondary structure as a whole prior to modification to provide a specific color or brightness characteristic while producing a uniform reflected light distribution within the set of viewing angles Ω v. Thus, the modification of the reflection surface element can smooth the modified area (the modified area is a part or the whole of the reflection surface element), that is, remove the secondary structure of the area to be modified, so that the secondary structure can generate a mirror reflection with a higher reflectivity for the whole visible light band.

94 are shown as patterns that produce sufficient contrast, the surface on which the reflective regions are located or the surface opposite the surface on which the reflective regions are located may have a plating or coating. This includes reflection enhancing coatings (especially metallized layers), reflection enhancing coatings, reflecting ink layers, absorbing ink layers, coatings of high refractive index materials. The reflection-enhancing coating, layer or layer of the reflective ink preferably has a color-shifting effect, i.e. a change in hue of the color at different viewing angles, for example by means of a Fabry-Perot interference structure, e.g. Cr (5 nm)/MgF ₂ (500 nm)/Al (50 nm) structure. Alternatively, the reflective areas and reflective surface elements may also be embossed in the reflective ink layer or the absorbing ink layer.

The reflective surface element may be modified such that the modified regions (which are part or all of the reflective surface element) have a different coating or thickness than the unmodified regions. For example, having a reflective coating, coating or ink on the modified areas, while not having a reflective coating, 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.

95 indicates that the modifying of the reflective surface element may be adjusting the angle of the modified region (the modified region is a portion or the whole of the reflective surface element) so as to reflect the incident light rays to a direction beyond Ω v. The pitch angle of the reflecting surface element is generally increased beyond a minimum set determined by the incident light directions ω i and Ω v, i.e., the incident light is reflected beyond the set determined by Ω v. The modified region provides no or little reflected light, resulting in a darker or darker visual perception than other regions.

96 indicates that the reflective surface elements can be modified in a serial combination of multiple modifications. For example, a recess lower than the peripheral region is formed in the modified region (the modified region is a part or the whole of the reflective surface element), then a secondary structure is added in the recess, and finally the reflective coating of the secondary structure region is removed (i.e. has a different thickness from the unmodified region); the recesses are formed lower in the modified area than in the peripheral area and filled with a color ink, the thickness of which is significantly greater than that of the ink in the unmodified area.

97 indicates that the modification of the reflection surface element can be combined in a parallel manner of a plurality of modification manners. For example, a flat depression may be formed in one portion of the modified region (which may be a portion or the entirety of a reflective surface element) and a secondary structure may be added along the orientation of the reflective surface element in another portion of the modified region. The modification of the reflection surface element can be a combination of the serial combination mode and the parallel combination mode of the modification modes.

The modified region may be present in part or in the entirety of the reflective surface element being modified. For an ideal planar reflective surface element, the modified area would be equal to the reflective surface element, while for a curved reflective surface element, the modified area would be present locally to the reflective surface element. 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 compared with the unmodified area.

In fig. 6, incident light 4 is reflected by reflective surface element 31 and reflective surface element 32 in

directions

51 and 52, respectively. The reflection light of the modified reflection surface element 31 generates a pattern of an animation frame, that is, the modified reflection surface elements are presented as the pattern of the animation frame together; the reflected light rays of the unmodified reflective surface elements 32 create the background of the animation frame, i.e., the unmodified reflective surface elements collectively appear as the background of the animation frame. The pattern area has a different optical contrast than the background area, and specifically may be one or a combination of different colors, different brightnesses, and different textures visible to human eyes.

Fig. 7 shows a schematic representation of a banknote 10, which banknote 10 has an optical security element according to the invention, which is embedded in 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 base material of the bank note, so that the optical anti-counterfeiting element is convenient to see in a light-transmitting mode. 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 care 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 also be used.

An embodiment of the present invention provides a storage medium, on which a program is stored, where the program, when executed by a processor, implements the method for designing an optical anti-counterfeit element according to any embodiment of the present invention.

The embodiment of the invention provides a processor, wherein the processor is used for running a program, and the program is used for executing the design method for the chemical anti-counterfeiting element in any embodiment of the invention when running.

The embodiment of the invention provides equipment, which comprises a processor, a memory and a program which is stored on the memory and can run on the processor, wherein the processor executes the program to realize the design method for the anti-counterfeiting element according to any embodiment of the invention.

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

As will be appreciated by one skilled in the art, 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 so forth) 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 flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams 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 a typical configuration, a computing device includes one or more processors (CPUs), input/output interfaces, network interfaces, and memory.

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

Computer-readable media, including both permanent and non-permanent, removable and non-removable media, may implement the 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 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 Disks (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. As defined herein, a computer readable medium does not include a transitory computer readable medium such as a modulated data signal and a carrier wave.

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 a … …" does not exclude the presence of another identical element in a process, method, article, or apparatus that comprises the element.

The above are merely examples of the present application and are not intended to limit the present application. Various modifications and changes may occur to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. An optical security element capable of presenting a dynamic feature, said dynamic feature being pre-designed as a reproduction of a set of animated frames visible at a set of preset viewing angles Ω v, said animated frames comprising a pattern region and a background region forming an optical contrast with said pattern region;

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 reflective area comprises a plurality of reflective surface elements including a wholly or partially modified reflective surface element and an unmodified reflective surface element, the modified reflective surface element and the unmodified reflective surface element having different reflective characteristics, wherein the modified reflective surface element corresponds to the pattern area;

when the diffuse reflection area is illuminated by the incident light, 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.

2. An optical security element according to claim 1, wherein the angles of the reflective surface elements of the plurality of reflective surface elements are randomly selected within a predetermined set of angles Ω s, wherein the elements within the predetermined set of viewing angles Ω v, the elements of the predetermined set of angles Ω s, and the angles of the incident light are related by a collective law of reflection.

3. An optical security element according to claim 2, wherein the angle of a reflective surface element of the plurality of reflective surface elements is determined by the inclination angle and the azimuth angle of the reflective surface element, the inclination angle preferably being 0 to 20 ° and/or the azimuth angle preferably being 0 to 360 °.

4. An optical security element according to claim 2,

the angles of the reflecting surface elements in the reflecting surface elements are obtained by randomly selecting the elements 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 set Ω s by using a pseudo random number generator.

5. An optical security element according to claim 1, wherein the lateral dimensions of the reflective surface elements of the plurality of reflective surface elements are from 3 μm to 100 μm, preferably from 10 μm to 30 μm.

6. An optical security element according to claim 1 wherein the reflective surface elements of the plurality of reflective surface elements are planar or curved.

7. An optical security element according to claim 1,

at least a portion of the unmodified reflective surface elements are smooth or have a secondary structure; andor or

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

8. An optical security 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:

adding a secondary structure to the modified reflective surface element;

smoothing the modified reflective surface element;

flattening the modified reflective surface element;

arranging the modified reflective surface elements to have a protrusion or a depression compared to the non-modified reflective surface elements;

adjusting the angle of the modified reflection surface element to enable the incident light to be reflected to a range beyond the preset observation angle set omega v; or

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

9. An optical security element according to claim 8 wherein where the modified reflective surface elements are modified by two or more of the plurality of means, the two or more means are present in a parallel combination and/or a serial combination.

10. An optical security element according to any one of claims 7 to 9, wherein the secondary structures have a lateral feature size of from 0.2 μm to 5 μm.

11. An optical security element according to claim 1, wherein the width of the modified region of the modified reflective surface element is from 0.5 μm to 30 μm, preferably from 2 μm to 10 μm.

12. An optical security element according to claim 1, wherein the different reflective characteristics refer to one or a combination of different reflective colors, different reflective brightnesses, or different reflective textures of the modified reflective surface elements and the unmodified reflective surface elements when the incident light is irradiated.

13. A method of designing a chemical security element, the method comprising:

designing a dynamic feature, wherein the dynamic feature is a reproduction of a group of animation frames visible at a preset observation angle set omega v, and each animation frame comprises a pattern area and a background area forming optical contrast with the pattern area;

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

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

when the diffuse reflection area is illuminated by the incident light, the modified reflective surface elements collectively appear as a pattern of the dynamic features and the unmodified reflective surface elements collectively appear as a background of the dynamic features.

14. The method of claim 13, wherein angles of reflective bins of the plurality of reflective bins are randomly selected within a predetermined set Ω s, wherein elements within the predetermined set of viewing angles Ω v, elements of the predetermined set Ω s, and angles of the incident light are related by a collective law of reflection.

15. The method according to claim 14, wherein an angle of a reflective bin of said plurality of reflective bins is determined by a tilt angle and an azimuth angle of said reflective bin, said tilt angle preferably being 0 to 20 ° and/or said azimuth angle preferably being 0 to 360 °.

16. The method of claim 14, wherein randomly selecting the angle of a reflection bin of the plurality of reflection bins within a preset set of angles Ω s comprises:

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

Randomly selecting an angle of a reflective surface element of the plurality of reflective surface elements from within the preset angle set Ω s by using a pseudo random number generation program.

17. The method of claim 13, wherein a lateral dimension of a reflective surface element of the plurality of reflective surface elements is from 3 μ ι η to 100 μ ι η, preferably from 10 μ ι η to 30 μ ι η.

18. The method of claim 13, wherein a reflective surface element of the plurality of reflective surface elements is planar or curved.

19. The method of claim 13, further comprising:

designing at least a portion of the unmodified reflective surface elements to be smooth or with secondary structures; andor or

At least some of the diffusely reflective regions are designed with a coating or layer.

20. The method of claim 13, wherein modifying a reflective surface element corresponding to the pattern area of the animation frames to form a modified reflective surface element comprises:

pixelating each animation frame of the set of animation frames;

determining a first azimuth angle and a first pitch angle of each animation frame, the first azimuth angle and the first pitch angle being determined according to an 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;

for each animation frame of the set of animation frames, performing the steps of:

searching for a reflection surface element corresponding to a second azimuth angle and a second pitch angle which are matched with 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, of the diffuse reflection area, 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 element corresponding to the pattern area of the animation frame, which is determined in the diffuse reflection area.

21. The method of claim 20, wherein finding a reflection bin corresponding to a second azimuth angle and a second elevation angle that match a first azimuth angle and a first elevation angle of the animation frame at a location 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 the angular difference between the first azimuth angle and a second pitch angle of one half of the first pitch angle within a second preset angular difference range 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.

22. The method of claim 21,

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

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

Said second predetermined angular difference range means an angular difference of less than 3 °, preferably less than 0.5 °, from said first pitch angle.

23. The method of claim 13, wherein modifying a reflective surface element corresponding to the pattern area of the animation frames to form a modified 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;

arranging the modified reflective surface elements to have a protrusion or depression as compared to an unmodified reflective surface element;

24. The method of claim 13,

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

The optical contrast is one or the combination of different colors, different brightness and different textures which can be seen by human eyes.

25. A method according to claim 13, wherein the width of the modified region of the modified reflective surface element is from 0.5 μm to 30 μm, preferably from 2 μm to 10 μm.

26. A security product using the optical security element according to any one of claims 1 to 12.

27. A data carrier, characterized in that it has an optical security element according to any one of claims 1 to 12 or a security product according to claim 26.