Anti-counterfeiting element and article having Anti-counterfeiting element

Abstract

Disclosed are an anti-counterfeiting element and an article having an anti-counterfeiting element. The anti-counterfeiting element comprises: a base material (4), wherein a feature region (5) is provided on a surface of the base material, and the feature region comprises a plurality of curved surface structures (6); and the curved surface structures have a first direction (1) and a second direction (2), which are parallel to the surface of the base material, the curved surface structures are arranged in a bent manner in the first direction, and the bending degree of each curved surface structure in the second direction is less than the bending degree of the curved surface structure in the first direction. By means of providing the plurality of curved surface structures in the feature region and arranging each curved surface structure in a bent manner in the first direction, under incident light in a predetermined direction, emergent light from the curved surface structures can be emitted within a fan-shaped direction range, and the angle distribution of the emergent light is uniform, thus achieving a dynamic effect with a higher resolution, and also achieving a finer and more stable appearance pattern and widening the range of viewing angles.

Description

Anti-counterfeiting elements and articles having such elements

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the China Patent Office on September 20, 2023, with application number 2023112203434 and invention name “Anti-counterfeiting element and article with anti-counterfeiting element”, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of anti-counterfeiting technology, and in particular to anti-counterfeiting elements and articles having anti-counterfeiting elements. Background Art

[0004] In order to prevent counterfeiting through scanning and copying, optical anti-counterfeiting technology is widely used in various high-security or high-value-added printed materials such as banknotes, cards and product packaging, and has achieved very good results.

[0005] Prior art discloses an anti-counterfeiting element comprising multiple reflective facets, each with a roughly random orientation. Under incident light from a predetermined direction, the orientation of the facets defines the direction of the emitted light, creating a dynamic effect where the appearance changes with viewing angle. However, this anti-counterfeiting element requires the use of multiple reflective facets to create a large area to achieve a uniform distribution of the emitted light angles. Furthermore, this combination of facets reduces the pattern resolution of the dynamic effect.

[0006] Summary of the Invention

[0007] In view of this, the present application provides an anti-counterfeiting element and an article having the anti-counterfeiting element to solve the problem in the prior art that a single reflective facet of the anti-counterfeiting element cannot achieve uniform distribution of the angle of the emitted light and the pattern resolution of the dynamic effect is low.

[0008] In a first aspect, the present application provides an anti-counterfeiting element, comprising:

[0009] A substrate, wherein a characteristic region is provided on a surface of the substrate, wherein the characteristic region includes a plurality of curved surface structures;

[0010] The curved surface structure has a first direction and a second direction parallel to the surface of the substrate. The curved surface structure is curved along the first direction, and the curvature of the curved surface structure along the second direction is smaller than the curvature of the curved surface structure along the first direction.

[0011] Beneficial effect: By arranging multiple curved surface structures in the characteristic area, and each curved surface structure is curved along the first direction, so that under the incident light in a predetermined direction, the outgoing light of the curved surface structure can be emitted within a fan-shaped direction range, and the angle distribution of the outgoing light is more uniform, that is, a single curved surface structure can obtain a combined effect equivalent to multiple reflective small faces in the prior art, which can not only achieve a higher resolution dynamic effect, but also achieve a more uniform angle distribution of the outgoing light, achieve a more refined and stable appearance pattern, and improve the viewing angle range.

[0012] In an optional embodiment, the degree of curvature of the curved surface structure along the first direction and the second direction is characterized by a slope.

[0013] In an optional embodiment, the slope distribution of the curved surface structure along the first direction and the second direction is continuous.

[0014] Beneficial effect: By setting the slope distribution of the curved surface structure along the first direction and the second direction to be continuous, there are no sharp corners on the curved surface structure, the angle of the emitted light is more uniform, the efficiency of the emitted light is higher, and the production quality is higher.

[0015] In an optional embodiment, the difference between the slopes of at least two locations of the curved surface structure along the first direction is greater than 0.05.

[0016] Beneficial effect: By setting the difference in the slope of the curved surface structure along the first direction to be larger, the viewing angle of the emitted light can be improved.

[0017] In an optional embodiment, the difference between the slopes of at least two locations of the curved surface structure along the first direction is greater than 0.1.

[0018] In an optional embodiment, the different curved surface structures have the same slope distribution range along the first direction.

[0019] Beneficial effect: By setting different curved surface structures to have the same slope distribution range along the first direction, the angles of emitted light from each curved surface structure are substantially the same, and the efficiency of emitted light is higher.

[0020] In an optional embodiment, cross sections of different curved surface structures along the first direction at least partially overlap.

[0021] In an optional embodiment, the cross-sectional shapes of the different curved surface structures along the first direction are the same.

[0022] Beneficial effect: By setting the cross-sectional shapes of different curved surface structures along the first direction to be the same, production efficiency can be improved.

[0023] In an optional embodiment, the cross-section of the curved surface structure along the first direction is convex and / or concave.

[0024] In an optional embodiment, a distance between a highest point and a lowest point of a cross section of the curved structure along the first direction is greater than 3 μm.

[0025] Beneficial effect: Since the cross-section of the curved surface structure along the first direction is set to be convex, concave or wavy, by limiting the distance between the highest point and the lowest point of the cross-section of the curved surface structure along the first direction to be greater than 3μm, the distance between the highest point and the lowest point will not be too small, thereby preventing the distance from being too small to produce unexpected diffraction effects.

[0026] In an optional embodiment, the average slope of the curved surface structure along the second direction is a predetermined value, and when the observation position is changed along the second direction, the appearance of the observed characteristic area changes with the change of the observation position.

[0027] Advantageous effect: By setting the average slope of the curved surface structure along the second direction to a predetermined value, information of the dynamic effect can be encoded according to the average slope of the curved surface structure along the second direction, so that the curved surface structure can achieve a pre-designed dynamic effect.

[0028] In an optional embodiment, the difference in slope of at least a portion of the curved surface structure along the second direction is less than 0.2.

[0029] Advantageous effect: By setting the difference in slope of at least a portion of the curved surface structure along the second direction to be smaller, the viewing angle can be increased and the resolution can be improved.

[0030] In an optional embodiment, the difference in slope of at least a portion of the curved surface structure along the second direction is less than 0.05.

[0031] In an optional embodiment, the curved structure is substantially straight along the second direction.

[0032] In an optional embodiment, at least some of the plurality of curved surface structures are curved along the second direction.

[0033] In an optional embodiment, the direction perpendicular to the surface of the substrate is the height direction, and the maximum height difference of the curved surface structure along the second direction is smaller than the maximum height difference of the curved surface structure along the first direction.

[0034] In an optional embodiment, the length of the curved surface structure along the second direction is less than 20 μm; and / or the length of the curved surface structure along the second direction is greater than 3 μm.

[0035] Beneficial effect: By limiting the length of the curved surface structure along the second direction, it is possible to prevent the curved surface structure from being too long along the second direction. If the curved surface structure is too long, the higher it is, and the more difficult the production process will be.

[0036] In an optional embodiment, the direction perpendicular to the surface of the substrate is the height direction, and the different curved surface structures have randomly set height differences.

[0037] Beneficial effect: By setting different curved surface structures to have randomly set height differences, the occurrence of unexpected diffraction phenomena can be suppressed.

[0038] In an optional embodiment, the curved structure is at least partially covered with a metal layer;

[0039] And / or, the curved surface structure is at least partially covered with a dielectric layer;

[0040] and / or, the curved surface structure is at least partially provided with a secondary microstructure;

[0041] And / or, the difference in refractive index between materials on both sides of the curved structure is greater than 0.1.

[0042] Beneficial effects: By providing a metal layer and a dielectric layer on the curved surface structure, the reflective effect of the curved surface structure can be enhanced, and the appearance of the curved surface structure changing color as the observation angle changes can be achieved; by limiting the difference in refractive index of the materials on both sides of the curved surface structure to be greater than 0.1, the refractive effect of the outgoing light can be improved.

[0043] In an optional embodiment, the slope difference of at least part of the curved surface structure along the first direction is between 1.4 times and 2.8 times the maximum average slope of the curved surface structure along the second direction; wherein the slope difference refers to a maximum value of the slope difference on a section drawn on a plane parallel to the first direction and the height direction of the curved surface structure, or a section drawn on a plane parallel to the second direction and the height direction of the curved surface structure.

[0044] In an optional embodiment, at least some of the boundaries of the adjacent curved structures are curved.

[0045] In an optional embodiment, a portion of the boundary of the curved surface structure is set according to the contour lines of the curved surface structure.

[0046] In a second aspect, the present application further provides an article having an anti-counterfeiting element, including: the above-mentioned anti-counterfeiting element.

[0047] Beneficial effects: Since the article with the anti-counterfeiting element includes the above-mentioned anti-counterfeiting element, it has the same effect as the anti-counterfeiting element, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0049] FIG1 is a schematic structural diagram of an anti-counterfeiting element according to an embodiment of the present application;

[0050] FIG2 is a schematic structural diagram of a cross section of the anti-counterfeiting element along a first direction and a height direction;

[0051] FIG3 is a schematic structural diagram of a cross section of the anti-counterfeiting element along the second direction and the height direction.

[0052] Explanation of reference numerals: 1 - first direction; 2 - second direction; 3 - height direction; 4 - substrate; 5 - feature area; 6 - curved surface structure. DETAILED DESCRIPTION

[0053] To make the purpose, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of this application.

[0054] The following describes an embodiment of the present application in conjunction with Figures 1 to 3.

[0055] According to an embodiment of the present application, in one aspect, a security element is provided, comprising: a substrate 4, having a feature region 5 disposed on a surface thereof, the feature region 5 including a plurality of curved structures 6; the curved structures 6 having a first direction 1 and a second direction 2 parallel to the surface of the substrate 4, where the first direction 1 and the second direction 2 are respectively the directions indicated by arrows 1 and 2 in FIG. 1 ; the curved structures 6 are curved along the first direction 1, and the degree of curvature of the curved structures 6 along the second direction 2 is less than the degree of curvature of the curved structures 6 along the first direction 1. By disposing the plurality of curved structures 6 in the feature region 5, each curved along the first direction 1, under incident light from a predetermined direction, light emitted from the curved structures 6 can be emitted within a fan-shaped directional range, resulting in a more uniform angular distribution of the emitted light. This allows a single curved structure 6 to achieve an effect equivalent to that achieved by combining multiple reflective facets in the prior art, achieving not only a higher-resolution dynamic effect but also a more uniform angular distribution of the emitted light, resulting in a more refined and stable appearance pattern and an improved viewing angle range.

[0056] As shown in Figure 1, the characteristic region 5 is shown as including nine curved surface structures 6 for exemplary purposes only. In practice, the size of each curved surface structure 6 is at least an order of magnitude smaller than that of the characteristic region 5. A characteristic region 5 may contain a considerable number of curved surface structures 6. While the diagram only uses a relatively small number of curved surface structures 6 for illustration, it does not represent the actual size, proportion, or number of such structures. Figures 2 and 3 are similar to Figure 1 and are merely screenshots showing several curved surface structures 6 for exemplary purposes only. They do not represent the actual size, proportion, or number of such structures.

[0057] In this embodiment, the curvature of the curved structure 6 along the first direction 1 and the second direction 2 is represented by a slope. As an alternative embodiment, the curvature of the curved structure 6 along the first direction 1 and the second direction 2 can also be represented by an inclination angle or other means.

[0058] The slope distribution of the curved surface structure 6 along the first direction 1 and the second direction 2 is continuous. By setting the slope distribution of the curved surface structure 6 along the first direction 1 and the second direction 2 to be continuous, there are no sharp corners on the curved surface structure 6, the angle of the emitted light is more uniform, the efficiency of the emitted light is higher, and the production quality is higher.

[0059] To improve the viewing angle of the emitted light, the difference in slope of at least two locations of the curved structure 6 along the first direction 1 is greater than 0.1. As an alternative embodiment, the difference in slope of at least two locations of the curved structure 6 along the first direction 1 may be between 0.05 and 0.1.

[0060] In one embodiment, different curved structures 6 have the same slope distribution range along the first direction 1. By arranging different curved structures 6 to have the same slope distribution range along the first direction 1, the angles of light emitted from each curved structure 6 are substantially the same, resulting in higher light emission efficiency. As an alternative embodiment, different curved structures 6 may have different slope distribution ranges along the first direction 1, or their slope distribution ranges may partially overlap.

[0061] As shown in Figure 2, the cross-sectional shapes of different curved surface structures 6 along the first direction 1 may be protruding, concave, or both protruding and concave, i.e., wavy. The cross-sectional shapes of different curved surface structures 6 along the first direction 1 may partially overlap, or not overlap at all. Some may have the same cross-sectional shape, or may have different cross-sectional shapes. The specific cross-sectional shape may be set according to actual needs, and no excessive restrictions will be imposed here.

[0062] Since the cross-section of the curved structure 6 along the first direction 1 is configured to be convex, concave, or wavy, the distance between the highest point and the lowest point of the cross-section of the curved structure 6 along the first direction 1 can be configured to be greater than 3 μm. This limitation ensures that the distance between the highest point and the lowest point of the cross-section of the curved structure 6 along the first direction 1 is not too small, preventing unintended diffraction effects caused by a too small distance. Of course, in specific settings, the distance between the highest point and the lowest point of the cross-section of the curved structure 6 along the first direction 1 can be configured to be 3.5 μm, 4 μm, 10 μm, 40 μm, etc., and no further limitations are imposed here.

[0063] The direction perpendicular to the surface of substrate 4 is defined as height direction 3, i.e., the direction indicated by arrow 3 in FIG2 . The height here refers to the depth of the curvature of curved structure 6. Different curved structures 6 have randomly set height differences, which can refer to the random height differences between different curved structures 6 as shown in FIG2 . The randomly set height differences here refer to specific values ​​randomly generated by a computer as the height differences. By setting the different curved structures 6 to have randomly set height differences, unintended diffraction phenomena can be suppressed.

[0064] To suppress unexpected diffraction effects, the curved structures 6 can be arranged in an irregular grid pattern, such as a random grid pattern. For example, different curved structures 6 can have different areas and / or different outer contours. To suppress unexpected diffraction effects, random height differences are provided between different curved structures 6.

[0065] In one embodiment, the average slope of the curved structure 6 along the second direction 2 is a predetermined value. When the observation position changes along the second direction 2, the appearance of the observed characteristic region 5 changes with the change in observation position. By setting the average slope of the curved structure 6 along the second direction 2 to a predetermined value, information about a dynamic effect can be encoded based on the average slope of the curved structure 6 along the second direction 2, so that the curved structure 6 achieves a pre-designed dynamic effect.

[0066] The difference in slope of at least a portion of the curved structure 6 along the second direction 2 is less than 0.05. Here, at least a portion of the curved structure 6 along the second direction 2 may comprise at least 70% of the area. By minimizing the difference in slope of at least a portion of the curved structure 6 along the second direction 2, the viewing angle and resolution can be increased. As an alternative embodiment, the difference in slope of at least a portion of the curved structure 6 along the second direction 2 may be between 0.05 and 0.2.

[0067] As shown specifically in Figure 3, the curved structure 6 is substantially straight along the second direction 2. In this case, when the observation position is changed along the first direction 1 of the curved structure 6, the degree to which the appearance of the observed characteristic region 5 changes with the change in observation position is smaller than when the observation position is changed along the second direction 2 of the curved structure 6. In this case, the resolution of the curved structure 6 is the highest, and the dynamic effect of the observed characteristic region 5 is the best.

[0068] As an alternative embodiment, at least some of the multiple curved structures 6 may be curved along the second direction 2. Since the contour lines of the curved structures 6 are curved, the boundaries of the curved structures 6 may be curved to imitate the shape of the contour lines, which helps to reduce the height difference at the boundaries.

[0069] The direction perpendicular to the surface of the substrate 4 is the height direction 3. The maximum height difference of the curved structure 6 along the second direction 2 is smaller than the maximum height difference of the curved structure 6 along the first direction 1, that is, the degree of curvature of the curved structure 6 along the second direction 2 is smaller than the degree of curvature of the curved structure 6 along the first direction 1.

[0070] Specifically, the length of the curved structure 6 along the second direction 2 is greater than 3 μm and less than 20 μm. By limiting the length of the curved structure 6 along the second direction 2, it is possible to prevent the curved structure 6 from being too long along the second direction 2. If the curved structure 6 is too long, the taller it becomes, and the more difficult the production process becomes. As an alternative embodiment, the length of the curved structure 6 along the second direction 2 may also be within other data ranges, and no further restrictions are imposed here.

[0071] In one embodiment, the curved structure 6 is covered with a metal layer and a dielectric layer, which can enhance the reflective effect of the curved structure 6. Specifically, the curved structure 6 can be at least partially covered with a metal-dielectric-metal three-layer structure. The metal-dielectric-metal three-layer structure can achieve an appearance that changes color with viewing angle, such as an aluminum-silicon dioxide-chromium three-layer structure. Alternatively, a dielectric-metal-dielectric three-layer structure or a multi-layer dielectric structure can also achieve similar appearance effects. As a variable embodiment, the curved structure 6 can be covered with only a metal layer or only a dielectric layer. As a variable embodiment, the curved structure 6 can be covered with only a metal layer, a dielectric layer, or both a metal layer and a dielectric layer.

[0072] In one embodiment, at least a portion of the curved structure 6 is provided with a secondary microstructure, such as a one-dimensional or two-dimensional grating with a period less than 450 nanometers. By providing the secondary microstructure, the color of the reflected light can be modulated, achieving an appearance of at least two colors at a fixed viewing angle.

[0073] In one embodiment, the difference in refractive index between the materials on both sides of the curved structure 6 is greater than 0.1. Since the difference in refractive index between the two sides of the curved structure 6 is required to achieve the refractive effect of light, the materials on both sides of the curved structure 6 can refer to the side of the curved structure 6 exposed to air. Generally, the interface between air and resin material has a large difference in refractive index, or the resin materials on both sides of the curved structure 6 have different refractive indices. By limiting the difference in refractive index between the materials on both sides of the curved structure 6 to greater than 0.1, the refractive effect of the emitted light can be improved.

[0074] In order to extend the life of the anti-counterfeiting element, a protective glue or a composite protective film may also be coated on the curved surface structure 6 .

[0075] In one embodiment, the slope difference of at least a portion of the curved surface structure 6 along the first direction 1 is between 1.4 and 2.8 times the maximum average slope of the curved surface structure 6 along the second direction 2. The slope difference refers to the maximum value of the slope difference between two points on the section line with the largest slope difference. The greater the slope difference, the greater the degree of curvature.

[0076] By setting the slope difference of the curved structures 6 along the first direction 1 to between 1.4 and 2.8 times the maximum average slope of the curved structures 6 along the second direction 2, consistency in observable angles can be achieved. Since the maximum slopes of the curved structures 6 in the first direction 1 and the second direction 2 should be approximately the same, and the slope distribution of a single curved structure 6 in the first direction 1 is approximately symmetrical, the maximum slope of a single curved structure 6 in the first direction 1 is half the slope difference of the single curved structure 6. Different curved structures 6 have different slopes in the second direction 2, and the maximum slope in the second direction 2 is the slope of the curved structure 6 with the largest average slope in the second direction 2. Therefore, in the most ideal case, the slope difference of the curved structures 6 in the first direction 1 is twice the maximum average slope of the curved surface in the second direction 2. As an alternative embodiment, the slope difference of the curved surface along the first direction 1 may be 1.4 times, 1.5 times, 2.5 times, or 2.8 times the maximum average slope of the curved surface 6 in the second direction 2.

[0077] In one embodiment, at least some of the boundaries of adjacent curved structures 6 are curved. This helps reduce height fluctuations at these boundaries, reduces the overall height of the curved structures 6, and thus reduces production difficulties. Specifically, some of the boundaries of the curved structures 6 are arranged along the contour lines of the curved structures 6. Because the boundaries of the curved structures 6 are curved, the curved structures 6 are arranged along the contour lines of the curved structures 6 at the boundaries, so that the edges of the curved structures 6 at the boundaries are of the same height. This arrangement can prevent height fluctuations at some of the edges of the curved structures 6.

[0078] The anti-counterfeiting element disclosed in this embodiment has the advantages of high resolution and uniform angular distribution of the emitted light. This embodiment improves the viewing angle range by customizing the morphology of the curved surface structure 6. A single curved surface structure 6 can achieve the combined effect of multiple randomly oriented optical facets in the prior art, achieving not only a higher-resolution dynamic effect but also a more uniform angular distribution of the emitted light, resulting in a more refined and stable appearance pattern.

[0079] The anti-counterfeiting element disclosed in this embodiment is more difficult to forge. The curved surface structure 6 with customized morphology has a higher degree of freedom and requires more parameters to describe a single curved surface structure 6. These parameters are difficult to measure and even more difficult to be copied and forged by counterfeiters.

[0080] According to an embodiment of the present application, on the other hand, an article with an anti-counterfeiting element is provided, including: the above-mentioned anti-counterfeiting element.

[0081] The article with anti-counterfeiting element in the present embodiment is a banknote. As a convertible embodiment, it is also possible that the article with anti-counterfeiting element is a security paper, or an identity card or other valuable documents, such as a chip card, a check, a receipt, a contract, a credit card or the like.

[0082] Part of the anti-counterfeiting element can be embedded in the banknote, and part of the structure can be exposed. As a convertible embodiment, the anti-counterfeiting element can be hot-stamped on the surface of the banknote by pre-coating hot melt adhesive, or the anti-counterfeiting element can be pasted on the surface of the banknote.

[0083] The anti-counterfeiting element can specifically be a security thread, a sealing tape, a security tape, a security strip, a patch, a label, etc., so as to be applied to items such as security paper and valuable documents.

[0084] Although the embodiments of the present application have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present application, and such modifications and variations shall fall within the scope defined by the appended claims.

Claims

1. An anti-counterfeiting element, characterized in that: include: A substrate (4), wherein a characteristic region (5) is provided on the surface of the substrate (4), and the characteristic region (5) includes a plurality of curved surface structures (6); The curved surface structure (6) has a first direction (1) and a second direction (2) parallel to the surface of the substrate (4); the curved surface structure (6) is arranged in a curved manner along the first direction (1); and the degree of curvature of the curved surface structure (6) along the second direction (2) is smaller than the degree of curvature of the curved surface structure (6) along the first direction (1).

2. The anti-counterfeiting element according to claim 1, characterized in that: The degree of curvature of the curved surface structure (6) along the first direction (1) and the second direction (2) is characterized by a slope.

3. The anti-counterfeiting element according to claim 2, characterized in that: The slope distribution of the curved surface structure (6) along the first direction (1) and the second direction (2) is continuous.

4. The anti-counterfeiting element according to claim 2, characterized in that: The difference between the slopes of at least two locations of the curved surface structure (6) along the first direction (1) is greater than 0.

05.

5. The anti-counterfeiting element according to claim 4, characterized in that: The difference between the slopes of at least two locations of the curved surface structure (6) along the first direction (1) is greater than 0.

1.

6. The anti-counterfeiting element according to claim 2, characterized in that: The different curved surface structures (6) have the same slope distribution range along the first direction (1).

7. The anti-counterfeiting element according to claim 1, characterized in that: The cross sections of the different curved surface structures (6) along the first direction (1) at least partially overlap.

8. The anti-counterfeiting element according to claim 7, characterized in that: The cross-sectional shapes of the different curved surface structures (6) along the first direction (1) are the same.

9. The anti-counterfeiting element according to claim 8, characterized in that: The cross-section of the curved surface structure (6) along the first direction (1) is convex and / or concave.

10. The anti-counterfeiting element according to claim 8, characterized in that: The distance between the highest point and the lowest point of the cross section of the curved surface structure (6) along the first direction (1) is greater than 3 μm.

11. The anti-counterfeiting element according to any one of claims 1 to 10, characterized in that: The average slope of the curved surface structure (6) along the second direction (2) is a predetermined value, and when the observation position is changed along the second direction (2), the appearance of the observed characteristic area (5) changes with the change of the observation position.

12. The anti-counterfeiting element according to claim 11, characterized in that: The difference in slope of at least a portion of the curved surface structure (6) along the second direction (2) is less than 0.

2.

13. The anti-counterfeiting element according to claim 12, characterized in that: The difference in slope of at least a portion of the curved surface structure (6) along the second direction (2) is less than 0.

05.

14. The anti-counterfeiting element according to claim 13, characterized in that: The curved structure (6) is substantially straight along the second direction (2).

15. The anti-counterfeiting element according to any one of claims 1 to 10, characterized in that: At least some of the curved surface structures (6) among the plurality of curved surface structures (6) are arranged in a curved manner along the second direction (2).

16. The anti-counterfeiting element according to claim 15, characterized in that: The direction perpendicular to the surface of the substrate (4) is the height direction (3), and the maximum height difference of the curved surface structure (6) along the second direction (2) is smaller than the maximum height difference of the curved surface structure (6) along the first direction (1).

17. The anti-counterfeiting element according to any one of claims 1 to 10, characterized in that: The length of the curved surface structure (6) along the second direction (2) is less than 20 μm; and / or the length of the curved surface structure (6) along the second direction (2) is greater than 3 μm.

18. The anti-counterfeiting element according to any one of claims 1 to 10, characterized in that: The direction perpendicular to the surface of the substrate (4) is the height direction (3), and the different curved surface structures (6) have randomly set height differences.

19. The anti-counterfeiting element according to any one of claims 1 to 10, characterized in that: The curved surface structure (6) is at least partially covered with a metal layer; And / or, the curved surface structure (6) is at least partially covered with a dielectric layer; And / or, the curved surface structure (6) is at least partially provided with a secondary microstructure; And / or, the difference in refractive index between materials on both sides of the curved structure (6) is greater than 0.

1.

20. The anti-counterfeiting element according to any one of claims 1 to 10, characterized in that: The slope difference of at least part of the curved surface structure (6) along the first direction (1) is between 1.4 and 2.8 times the maximum average slope of the curved surface structure (6) along the second direction (2); wherein the slope difference refers to the maximum value of the difference in slopes on a section drawn on a plane parallel to the first direction (1) and the height direction (3) of the curved surface structure (6), or on a section drawn on a plane parallel to the second direction (2) and the height direction (3) of the curved surface structure (6).

21. The anti-counterfeiting element according to any one of claims 1 to 10, characterized in that: At least some of the boundaries of the adjacent curved surface structures (6) are arranged in a curved manner.

22. The anti-counterfeiting element according to claim 21, characterized in that: Part of the boundary of the curved surface structure (6) is arranged according to the contour lines of the curved surface structure (6).

23. An article having an anti-counterfeiting element, characterized in that: include: The security element according to any one of claims 1 to 22.

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