Optical security element and security product

Abstract

The application provides an optical anti-counterfeiting element and an anti-counterfeiting product. The optical anti-counterfeiting element comprises a substrate, and a code pattern, wherein a part of a side surface of the substrate is provided with the code pattern, the code pattern reproduces preset information through decoding, the code pattern comprises a first part and a second part, the first part and the second part are arranged in mutual embedding, the first part is transparent, and at least a local characteristic size of the first part is not greater than 5 microns, the second part comprises an optical microstructure and a plating layer covering the optical microstructure on a side surface away from the substrate, when a light beam is incident on the first part and the second part, the second part provides a line optical anti-counterfeiting feature in a reflection light direction and near the reflection light direction visible to a human eye, the first part generates a transmission light field, and the transmission light field reproduces the preset information. The application solves the problem that the optical anti-counterfeiting element in the prior art is difficult to simultaneously consider concealment and security.

Description

Technical Field

[0001] This invention relates to the field of optical anti-counterfeiting technology, and more specifically, to an optical anti-counterfeiting element and an anti-counterfeiting product. Background Technology

[0002] To prevent counterfeiting, optical anti-counterfeiting technologies are widely used in banknotes, certificates, and other high-security and high-value-added printed materials, with very good results. For example, the new versions of the Euro and Canadian polymer banknotes use diffractive optically variable image wide bars, and the $100 US dollar note uses a technology called... The new 100 RMB banknote features a microlens security thread, and its optical variable security thread is used in many other applications. Visa, MasterCard, and my country's UnionPay credit cards use diffractive optical variable image hot stamping. Important Chinese documents such as ID cards, driver's licenses, and passports also employ diffractive optical variable image anti-counterfeiting technology. To date, most banknotes, credit cards, passports, and other security documents worldwide utilize optical anti-counterfeiting technology.

[0003] Existing optical anti-counterfeiting elements generally employ certain optical microstructures to generate special optical effects, presenting unique and difficult-to-counterfeit visual effects to achieve the purpose of first-line mass anti-counterfeiting. However, simply possessing the visual effect of mass anti-counterfeiting is insufficient to meet current market demands. Furthermore, while hidden images reproduced by point light sources or lasers can provide unique anti-counterfeiting features, these hidden image features cannot simultaneously possess the first-line mass anti-counterfeiting images or features that are directly observable to the human eye in or near the direction of reflected light. Moreover, all hidden patterns must be projected onto a designated screen, limiting observation conditions and hindering identification. Forcing direct observation with the human eye could also cause eye burns due to excessive energy, which is unacceptable to users.

[0004] In other words, existing optical anti-counterfeiting components have the problem of not being able to simultaneously achieve both concealment and security. Summary of the Invention

[0005] The main objective of this invention is to provide an optical anti-counterfeiting element and anti-counterfeiting product to solve the problem that existing optical anti-counterfeiting elements cannot simultaneously achieve both concealment and security.

[0006] To achieve the above objectives, according to one aspect of the present invention, an optical anti-counterfeiting element is provided, comprising: a substrate; an coded pattern, wherein at least a portion of one side surface of the substrate is provided with the coded pattern, the coded pattern reproduces pre-set information by decoding, the coded pattern includes a first part and a second part, the first part and the second part are interlocked, the first part is transparent and at least a local feature size of the first part is not greater than 5 μm, the second part includes an optical microstructure and a coating conformally covering the side surface of the optical microstructure away from the substrate, when a light beam is incident on the first part and the second part, the second part provides a line optical anti-counterfeiting feature visible to the human eye in and near the direction of reflected light, the first part generates a transmitted light field and the transmitted light field reproduces the pre-set information.

[0007] Furthermore, the projected area of ​​the second part on the substrate is larger than the projected area of ​​the first part on the substrate.

[0008] Furthermore, the first and second parts are spliced ​​together to form the entire coded pattern.

[0009] Furthermore, the encoding pattern is one of the transformation patterns of Fourier transform, Fresnel transform, Moiré encoding, barcode, QR code, Hilbert transform, Abel transform, and Merlin transform.

[0010] Furthermore, the optical microstructure is defined as follows: when a light beam enters the optical microstructure at a first incident angle, the light beam of a first wavelength or a first wavelength range in the light beam is constructively interfered in the direction of reflected light, and at least a portion of the optical microstructure has a predetermined depth so that at least a portion of the optical anti-counterfeiting element presents a first color in the direction of reflected light.

[0011] Furthermore, the pattern of at least a portion of the optical microstructure is at least one or a combination of at least two of the following: the units of the optical microstructure are randomly or pseudo-randomly distributed in both the first and second directions; the units of the optical microstructure are periodically distributed in the first direction and randomly or pseudo-randomly distributed in the second direction; or the units of the optical microstructure are randomly or pseudo-randomly distributed only in the second direction.

[0012] Furthermore, when the units of the optical microstructure are randomly or pseudo-randomly distributed in both the first and second directions, the feature size of at least a portion of the optical microstructure is greater than or equal to 0.3 μm and less than or equal to 6 μm, and the depth of at least a portion of the optical microstructure satisfies the following: when the light beam irradiates the optical microstructure at the first incident angle, at least a portion of the optical anti-counterfeiting element presents a second color in the direction of scattered light.

[0013] Furthermore, when the units of the optical microstructure are randomly or pseudo-randomly distributed in the second direction, at least a portion of the optical microstructure has a feature size greater than or equal to 0.3 μm and less than or equal to 6 μm in the second direction, and a feature size greater than 6 μm in the first direction. In addition, the depth of at least a portion of the optical microstructure also satisfies the following condition: when the light beam is incident on the optical microstructure at the first incident angle and the light beam is perpendicular to the plane where the substrate is located, and the second direction is on the plane, then at least a portion of the optical anti-counterfeiting element presents a second color in the direction of scattered light in the plane.

[0014] Furthermore, when the units of the optical microstructure are periodically distributed in the first direction and randomly or pseudo-randomly distributed in the second direction, at least a portion of the optical microstructure has a feature size greater than or equal to 0.3 μm and less than or equal to 6 μm in the first direction, and a feature size greater than or equal to 0.3 μm and less than or equal to 6 μm in the second direction. The depth of at least a portion of the optical microstructure also satisfies the following: when a light beam is incident on the optical microstructure at a first incident angle, and the beam is perpendicular to the plane containing the substrate, and the second direction is on the plane, at least a portion of the optical anti-counterfeiting element exhibits a second color in the direction of scattered light within the plane; and / or when a light beam is incident on the optical microstructure at a first incident angle, and the beam is perpendicular to the plane containing the substrate, and the first direction is on the plane, at least a portion of the optical anti-counterfeiting element exhibits a +1 or -1 order diffraction color that varies with the angle in the direction of diffraction light within the plane.

[0015] Furthermore, the optical microstructure is a subwavelength microstructure.

[0016] Furthermore, the subwavelength microstructure is a one-dimensional grating, and the groove shape of the one-dimensional grating includes one or more of sinusoidal, rectangular, and sawtooth shapes; or the subwavelength microstructure is a two-dimensional grating, and the groove shape of the two-dimensional grating includes one or more of sinusoidal, rectangular, and sawtooth shapes.

[0017] Furthermore, the groove depth of the subwavelength microstructure is greater than or equal to 10 nm and less than or equal to 500 nm; and / or the feature size of the subwavelength microstructure in its two-dimensional plane is greater than or equal to 50 nm and less than or equal to 500 nm.

[0018] Furthermore, the groove depth of the subwavelength microstructure is greater than or equal to 50 nm and less than or equal to 300 nm; and / or the feature size of the subwavelength microstructure in its two-dimensional plane is greater than or equal to 200 nm and less than or equal to 400 nm.

[0019] Furthermore, the optical microstructure includes one or more of non-diffractive microstructures and diffractive microstructures. When the optical microstructure includes a non-diffractive microstructure, the size of the non-diffractive microstructure is greater than 5 micrometers. When the optical microstructure includes a diffractive microstructure, the size of the diffractive microstructure is greater than or equal to 0.1 micrometers and less than or equal to 5 micrometers.

[0020] Furthermore, the optical anti-counterfeiting element also includes a first functional layer located between the substrate and the coded pattern, and / or a second functional layer located on the side of the coded pattern away from the substrate. The first functional layer includes one of a release layer, a reinforcing layer, a protective layer, a magnetic layer, a fluorescent layer, and an infrared layer; the second functional layer includes one of a release layer, a reinforcing layer, a protective layer, a magnetic layer, a fluorescent layer, and an infrared layer.

[0021] Furthermore, the coating can be one or more layers. When the coating is multi-layered, the multi-layered coating forms a Fabry-Poisson resonant cavity.

[0022] Furthermore, the proportion of transmitted light in the first part is more than 10% higher than that in the second part.

[0023] Furthermore, the proportion of transmitted light in the first part is more than 20% higher than that in the second part.

[0024] Furthermore, the substrate is a polyvinyl chloride (PVC) board, a polyethylene terephthalate (PET) board, a polycarbonate (PC) board, or a glass board.

[0025] According to another aspect of the present invention, an anti-counterfeiting product is provided, which includes the above-described optical anti-counterfeiting element.

[0026] According to the technical solution of the present invention, the optical anti-counterfeiting element includes a substrate and an encoding pattern. At least a portion of one side surface of the substrate is provided with the encoding pattern. The encoding pattern reproduces the pre-set information by decoding. The encoding pattern includes a first part and a second part, which are interlocked with each other. The first part is transparent and at least a local feature size of the first part is no greater than 5 μm. The second part includes an optical microstructure and a coating that conformally covers the side surface of the optical microstructure away from the substrate. When a light beam is incident on the first part and the second part, the second part provides a line optical anti-counterfeiting feature visible to the human eye in and near the direction of reflected light. The first part generates a transmitted light field and the transmitted light field reproduces the pre-set information.

[0027] This application achieves first-line optical anti-counterfeiting features through the optical microstructure of the second part and the coating that conformally covers the surface of the optical microstructure. These features include holographic diffraction characteristics, reflection characteristics, interference characteristics, and scattering characteristics in or near the direction of reflected light, providing features that can be observed by the human eye. On the other hand, by setting a transparent first part and constraining the feature size of the first part to no more than 5μm, the feature size of the first part is small enough that the transmitted light field generated by the first part can be received by the naked eye without causing burns, thus protecting the user's health. This allows for direct observation with the naked eye, eliminating the need to receive pre-set information through a screen. This achieves a second-line hidden anti-counterfeiting feature that is easier for the public to identify, increasing anti-counterfeiting capabilities and providing further protection for the first-line optical anti-counterfeiting features. In summary, this application, by interlocking the first part and the second part, when a light beam is incident on the first part and the second part, the second part provides a line-of-fact optical anti-counterfeiting feature visible to the human eye in and around the direction of the reflected light, while the first part generates a transmitted light field that reproduces pre-set information. This allows the first part to provide a two-line hidden anti-counterfeiting feature. Furthermore, by constraining the size of the first part, the hidden feature of the first part can be directly observed by the human eye without causing harm, thus increasing anti-counterfeiting while ensuring the safety of user observation. Attached Figure Description

[0028] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0029] Figure 1 A schematic diagram of an optical anti-counterfeiting element according to an optional embodiment of the present invention is shown;

[0030] Figure 2 It shows Figure 1 A magnified view of a portion of the coded pattern;

[0031] Figure 3 It shows Figure 1 A cross-sectional schematic diagram of the periodic optical microstructure of an optical anti-counterfeiting element in an optical system;

[0032] Figure 4 It shows Figure 1 A cross-sectional schematic diagram of another optical microstructure periodicity of the optical anti-counterfeiting element in the image;

[0033] Figure 5 A schematic diagram of an optical anti-counterfeiting element according to another optional embodiment of the present invention is shown;

[0034] Figure 6a A top view of an optical microstructure of the optical anti-counterfeiting element of the present invention is shown;

[0035] Figure 6b A cross-sectional view of another optical microstructure of the optical anti-counterfeiting element of the present invention is shown;

[0036] Figure 6c A cross-sectional view of another optical microstructure of the optical anti-counterfeiting element of the present invention is shown;

[0037] Figure 6d A cross-sectional view of another optical microstructure of the optical anti-counterfeiting element of the present invention is shown;

[0038] Figure 7a A top view of another optical microstructure of the optical anti-counterfeiting element of the present invention is shown;

[0039] Figure 7b A cross-sectional view of another optical microstructure of the optical anti-counterfeiting element of the present invention is shown;

[0040] Figure 8a A top view of another optical microstructure of the optical anti-counterfeiting element of the present invention is shown;

[0041] Figure 8b A cross-sectional view of another optical microstructure of the optical anti-counterfeiting element of the present invention in one direction is shown;

[0042] Figure 8c A cross-sectional view of another optical microstructure of the optical anti-counterfeiting element of the present invention in another direction is shown;

[0043] Figure 9 A cross-sectional view of another optical microstructure of the optical anti-counterfeiting element of the present invention is shown.

[0044] Figure 10 An image showing the effect of an optical anti-counterfeiting element according to an optional embodiment of the present invention is provided.

[0045] Figure 11 An image illustrating the effect of an optical anti-counterfeiting element according to another optional embodiment of the present invention is shown;

[0046] Figure 12 An image illustrating the effect of an optical anti-counterfeiting element according to another alternative embodiment of the present invention is shown.

[0047] The above figures include the following reference numerals:

[0048] 1. Optical anti-counterfeiting element; 101. Code pattern; 102. Additional area; 201. First part; 202. Second part; 302. Optical microstructure; 402. Coating; 5. Sun; 6. Substrate; 7. Adhesive layer; 8. Release layer. Detailed Implementation

[0049] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0050] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0051] In this invention, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally used in relation to the direction shown in the accompanying drawings, or in relation to the vertical, perpendicular, or gravitational direction of the component itself; similarly, for ease of understanding and description, "inner" and "outer" refer to the inner and outer contours of each component itself, but the above directional terms are not intended to limit this invention.

[0052] To address the problem that existing optical anti-counterfeiting elements cannot simultaneously achieve both concealment and security, this invention provides an optical anti-counterfeiting element 1 and an anti-counterfeiting product.

[0053] like Figures 1 to 12 As shown, the optical anti-counterfeiting element 1 includes a substrate 6 and an encoding pattern 101. At least a portion of one side surface of the substrate 6 is provided with the encoding pattern 101. The encoding pattern 101 reproduces pre-set information through decoding. The encoding pattern 101 includes a first part 201 and a second part 202. The first part 201 and the second part 202 are interlocked. The first part 201 is transparent and at least a local feature size of the first part 201 is no greater than 5 μm. The second part 202 includes an optical microstructure 302 and a coating 402 that conformally covers the side surface of the optical microstructure 302 away from the substrate 6. When a light beam is incident on the first part 201 and the second part 202, the second part 202 provides a line-of-sight optical anti-counterfeiting feature visible to the human eye in the direction of reflected light and in its vicinity. The first part 201 generates a transmitted light field and the transmitted light field reproduces the pre-set information.

[0054] This application achieves first-line optical anti-counterfeiting features for the coded pattern 101 through the optical microstructure 302 of the second part 202 and the coating 402 conformally covering the surface of the optical microstructure 302, such as holographic diffraction features, reflection features, interference features, and scattering features in or near the direction of reflected light, providing features that can be observed by the human eye. On the other hand, by setting a transparent first part 201 and constraining the feature size of the first part 201 to no more than 5μm, the feature size of the first part 201 is made small, thereby allowing the transmitted light field generated by the first part 201 to be received by the naked eye without causing burns, protecting the user's health. This enables direct observation with the naked eye, eliminating the need to receive pre-set information through a screen, and realizing a second-line hidden anti-counterfeiting feature that is easier for the public to identify, increasing anti-counterfeiting effectiveness and providing further protection for the first-line optical anti-counterfeiting feature. In summary, this application, by interlocking the first part 201 and the second part 202, allows the second part 202 to provide a line-of-sight optical anti-counterfeiting feature visible to the human eye in the direction of reflected light and its vicinity when a light beam is incident on the first part 201 and the second part 202. The first part 201 generates a transmitted light field that reproduces pre-set information, thereby enabling the first part 201 to provide a two-line hidden anti-counterfeiting feature. Furthermore, by constraining the size of the first part 201, the hidden feature of the first part 201 can be directly observed by the human eye without causing harm, thus increasing anti-counterfeiting while ensuring the safety of user observation.

[0055] More specifically, the optical anti-counterfeiting element 1 of the present invention overcomes the problem that the first-line anti-counterfeiting features and the second-line hidden anti-counterfeiting features of the prior art cannot coexist, as well as the problem that the second-line hidden anti-counterfeiting features are not easy to observe and are easy to burn the eyes. The optical anti-counterfeiting element 1 of this application has a first-line common optical anti-counterfeiting feature in or near the direction of reflected light, and a second-line hidden anti-counterfeiting feature with controllable brightness.

[0056] It should be noted that the first part 201 is transparent, meaning that the coating 402 and optical microstructure 302 are not provided on the first part 201. The aforementioned light beam originates from a point light source, meaning that a point light source is used to provide the aforementioned light beam; more specifically, the aforementioned light beam originates from a monochromatic point light source.

[0057] It should also be noted that, such as Figure 2As shown, the projection shapes of the first part 201 and the second part 202 on the substrate 6 are both irregular random shapes. The first part 201 and the second part 202 are interlocked, which can also be understood as the first part 201 and the second part 202 interweaving and complementing each other, so that the first part 201 and the second part 202 are spliced ​​together to form the entire coding pattern 101. That is to say, the position and appearance of the optical microstructure 302 of the second part 202 are spliced ​​together with the position and appearance of the first part 201 without error. At the same time, the feature size in the at least local feature size of the first part 201 mentioned above refers to the size in any direction on the two-dimensional plane where the first part 201 is located.

[0058] like Figures 1 to 4 As shown, an alternative embodiment of the optical anti-counterfeiting element 1 of the present invention is described. The substrate 6 of the optical anti-counterfeiting element 1 has an encoding pattern 101 and an additional area 102 other than the encoding pattern 101 on one side surface. The encoding pattern 101 is a pattern obtained by encoding the original pattern, i.e., the pre-set information. In addition, the pre-set information is reproduced by decoding the encoding pattern 101, thereby providing hidden information for second-line anti-counterfeiting.

[0059] like Figure 2 As shown, Figure 2 A partially enlarged view of the coding pattern 101 is shown. It can be seen from the image that the first part 201 and the second part 202 of the coding pattern 101 have a complementary relationship. Figure 3 and Figure 4 The figure shows an enlarged cross-sectional view of the optical anti-counterfeiting element 1 along a direction perpendicular to the surface of the substrate 6. As can be seen from the figure, the first part 201 on the surface of the substrate 6 is transparent, that is, hollow; the second part 202 includes an optical microstructure 302 and a coating 402 that conformally covers the surface of the optical microstructure 302. Figure 3 The optical microstructure 302 is a one-dimensional holographic diffraction grating with a period of 1 micrometer and a depth of 500 nanometers. The parameters can also be changed, for example, to select a one-dimensional holographic diffraction grating with a period of 2 micrometers and a depth of 120 nanometers. Figure 4 The period and depth of the optical microstructure 302 are related to Figure 3 different. Figure 4 The optical microstructure 302 is a one-dimensional non-diffraction grating with a period of 6 micrometers and a depth of 3 micrometers. The parameters can be changed, and the optical microstructure 302 can even be selected as a flat surface.

[0060] Preferably, the optical microstructure 302 can be selected as a non-diffractive structure, a diffractive structure, or a combination thereof. The surface of the optical microstructure 302 away from the substrate 6 can also be a flat, smooth surface. The size of the non-diffractive microstructure is typically larger than 5 micrometers to ensure that no obvious rainbow colors are produced, while the size of the diffractive microstructure is typically between 0.1 micrometers and 5 micrometers. The coating 402 can be formed on the optical microstructure 302 by physical deposition or chemical deposition methods, such as, but not limited to, thermal evaporation, magnetron sputtering, MOCVD, molecular beam epitaxy, etc.

[0061] like Figure 3 and Figure 4 As shown, the first part 201 is transparent because it does not have any microstructure and coating 402. Furthermore, the first part 201 has higher transparency than the second part 202. When the sun 5 shines on the coded pattern 101, the proportion of transmitted light in the first part 201 is higher than that in the second part 202.

[0062] Specifically, the encoding pattern 101 is one of the following transformation patterns: Fourier transform pattern, Fresnel transform pattern, Moiré encoding pattern 101, barcode, QR code, Hilbert transform pattern, Abelian transform pattern, Merlin transform pattern, or various custom transformation patterns, thereby defining the specific association and distribution of the first part 201 and the second part 202 interlocking. This allows the transmitted light field of the encoding pattern 101 to further reproduce the pre-defined information.

[0063] The following examples illustrate several forms of the coded pattern 101:

[0064] The coded pattern 101 can be a Fourier transform pattern, that is, a Fourier pattern obtained by transforming the original pattern. The Fourier transform pattern can be obtained through computer calculation or through optical transformation.

[0065] The coded pattern 101 can be a Fresnel transform pattern, that is, a Fresnel transform pattern obtained after the original pattern has undergone a Fresnel transform. Fresnel transform patterns can be obtained through computer calculation or through optical transformation.

[0066] The coding pattern 101 can be a moiré coding pattern 101, that is, a pattern obtained by moiré coding from the design key plate and the original pattern;

[0067] The encoding pattern 101 can be a barcode, a QR code, a Hilbert transform pattern, an Abel transform pattern, a Merlin transform pattern, or various custom transform patterns.

[0068] Through decoding, the encoded pattern 101 reveals the hidden original image. The decoding process is actually the inverse operation of the encoding process. Different encoding methods have different specific decoding methods.

[0069] Fourier transform patterns and Fresnel transform patterns can be read into a computer, decoded by the computer, and the original image reproduced on the computer screen. Optical transform decoding can also be used, where a beam of light (usually a laser) illuminates the encoded pattern 101, reproducing the hidden original image at an appropriate distance.

[0070] The moiré-coded pattern 101 is decoded using a keypad; that is, the decoded keypad is overlaid on top of it, and its position and alignment are adjusted to reproduce the hidden original image. Alternatively, a virtual keypad can be stored in a computer, and the moiré-coded pattern 101 can be read into the computer and decoded using a program.

[0071] Barcodes, QR codes, Hilbert transform patterns, Abel transform patterns, Merlin transform patterns, etc., need to be decoded by a computer.

[0072] Specifically, the transmitted light ratio of the first part 201 is more than 10% higher than that of the second part 202. Preferably, the transmitted light ratio of the first part 201 is more than 20% higher than that of the second part 202.

[0073] In practical applications, the amount of transmitted light through the first part 201 can be adjusted by making the characteristic size of the first part 201 sufficiently small. The characteristic size of the first part 201 refers to the width of the stroke or line of the first part 201 in any direction on its two-dimensional plane. For example... Figure 2 In the diagram, at the point where the dashed line A~B is drawn, the distance between points A and B is the feature size of the first part 201 at that location. In practical applications, the feature size of the first part 201 can be controlled to be small enough to ensure that the noise and brightness of the coded pattern 101 are within an acceptable range. Preferably, the feature size of at least a local part of the first part 201 is no greater than 5μm.

[0074] Specifically, the first-line optical anti-counterfeiting feature formed by the optical microstructure 302 and the coating 402 in the second part 202 requires a sufficiently high proportion of the actual area covered by the second part 202 to ensure that the optical anti-counterfeiting feature is clear and bright enough. Considering the requirement that the feature size of the first part 201 needs to be sufficiently small, the projected area of ​​the second part 202 on the substrate 6 is larger than the projected area of ​​the first part 201 on the substrate 6 to ensure that both the first-line optical anti-counterfeiting feature and the coding pattern 101 are relatively clear. Figure 2For example, the areas of the first part 201 and the second part 202 are almost the same. By reducing the feature size of the first part 201 to below 5μm and increasing the area of ​​the second part 202, a higher quality optical anti-counterfeiting feature can be obtained, thereby giving the optical anti-counterfeiting element 1 of the present invention a higher anti-counterfeiting capability. In summary, the projected area of ​​the second part 202 on the substrate 6 is larger than that of the first part 201 on the substrate 6. This setting is beneficial to reducing the area of ​​the first part 201, while ensuring that the second part 202 has a sufficiently large area so that it can clearly and stably provide a first-line optical anti-counterfeiting feature visible to the human eye. At the same time, the area occupied by the first part 201 is small, which allows the transmitted light field generated by the first part 201 to be received by the naked eye without causing burns, protecting the user's health. This enables direct observation with the naked eye, eliminating the need to receive pre-set information through a screen, and realizing a second-line hidden anti-counterfeiting feature that is easier for the public to identify, increasing anti-counterfeiting capability and providing further protection for the first-line optical anti-counterfeiting feature.

[0075] In addition, the Sun 5 provides a beam of light for illumination, which can be changed into other types of surface light sources, line light sources, parallel light sources, or point light sources, such as LED lights, incandescent lamps, mobile phone flashlights, etc. It can also be changed into a monochromatic light source, such as a gas laser, semiconductor laser, laser pointer, etc.

[0076] It should be noted that when using a monochromatic point light source, the clarity of the reproduced hidden anti-counterfeiting image, i.e., the pre-set information, as perceived by the human eye is optimal. However, when using a non-monochromatic point light source, due to the dispersion between different wavelengths of light, multiple images of different colors will appear corresponding to different wavelengths, resulting in multiple overlapping images. The inventors found in practical applications that this ghosting caused by different colored images is acceptable. Since obtaining a monochromatic light source is far more difficult than obtaining a non-monochromatic light source in practical applications, this discovery also makes the optical anti-counterfeiting element 1 of this invention more easily identifiable and more conducive to practical application, which is something that traditional methods of reproducing hidden encoded images do not possess. In addition, a non-point light source is equivalent to the superposition of multiple point light sources at different locations. Correspondingly, the human eye will receive images from multiple different locations, which will make it impossible to accurately identify the pre-set information. This characteristic can be used to effectively hide anti-counterfeiting images under normal ambient light, while point light sources should be selected whenever possible when it is necessary to identify hidden images.

[0077] In summary, the optical anti-counterfeiting element 1 can control the transmitted light flux of the first part 201 and the area ratio of the first part 201 and the second part 202 by controlling the feature size of the first part 201 and the area ratio of the second part 202. The coded pattern 101 reproduces the pre-set information through decoding, and the brightness of the coded pattern 101 can be arbitrarily adjusted by the transmitted light flux, so that the transmitted light can be received by the naked eye without causing burns, protecting the user's health. This allows for direct observation with the naked eye, eliminating the need to receive pre-set information through a screen, and realizing a more easily identifiable second-line hidden anti-counterfeiting feature, thus increasing the anti-counterfeiting effectiveness.

[0078] Specifically, the substrate 6 is a polyvinyl chloride (PVC) board, a polyethylene terephthalate (PET) board, a polycarbonate (PC) board, or a glass board. Alternatively, one or more functional coating materials can be applied to the surface of these base materials, depending on the specific requirements of the product. Optionally, the functional layers include, but are not limited to, a release layer 8, a reinforcing layer, a protective layer, a magnetic layer, a fluorescent layer, and an infrared layer. One or more of the aforementioned functional layers can also be further applied to the upper surface of the coating 402.

[0079] like Figure 5 The diagram illustrates another optional embodiment of the optical anti-counterfeiting element 1 of the present invention. In this embodiment, the optical anti-counterfeiting element 1 includes a substrate 6 made of PET (or other sheet material), with a release layer 8 coated on its surface. A coding pattern 101 is disposed on the surface of the release layer 8 away from the substrate 6. The coding pattern 101 is configured the same as in the previous embodiment. The optical anti-counterfeiting element 1 also includes an adhesive layer 7 disposed on the side of the coding pattern 101 away from the release layer 8, and the adhesive layer 7 fills the coding pattern 101. With this configuration, the optical anti-counterfeiting element 1 possesses a peel-and-transfer function, meaning that the coding pattern 101 can be hot-stamped and pasted onto a high-security product carrier such as banknotes, securities, credit cards, or passports using, for example, a hot stamping process and the adhesive function of the adhesive layer 7, and the substrate 6 can be peeled off, thereby ensuring a relatively thin overall structure on the target carrier. Preferably, at least a portion of the high-security product carrier is transparent, and the transparent area at least partially overlaps with the coding pattern 101.

[0080] Specifically, the optical microstructure 302 can be made into a master template by laser etching, electron beam etching, ion etching, etc., and then copied onto the substrate 6 by electroforming, molding, UV replication, etc. A more common process is to coat an imaging layer on the surface of the substrate 6 and copy the optical microstructure 302 onto the imaging layer, in order to improve the replication quality and efficiency of the optical microstructure 302.

[0081] Specifically, the optical microstructure 302 and coating 402 of the second part 202 provide a line-of-sight optical anti-counterfeiting feature in the direction of reflected light visible to the human eye and its vicinity. When the optical microstructure 302 is a diffractive microstructure, it provides diffraction holographic features; when the optical microstructure 302 is a non-diffractive microstructure, it provides reflection features.

[0082] Specifically, the pattern of at least a portion of the optical microstructure 302 is at least one of the following, or a combination or any combination of at least two of them:

[0083] The units of the optical microstructure 302 are randomly or pseudo-randomly distributed in both the first and second directions;

[0084] The units of the optical microstructure 302 are periodically distributed in the first direction and randomly or pseudo-randomly distributed in the second direction.

[0085] The units of the optical microstructure 302 are randomly or pseudo-randomly distributed only in the second direction.

[0086] At this time, when the units of the optical microstructure 302 are randomly or pseudo-randomly distributed in both the first and second directions, the feature size of at least a portion of the optical microstructure 302 is greater than or equal to 0.3 μm and less than or equal to 6 μm, and the depth of at least a portion of the optical microstructure 302 satisfies the following: when the light beam irradiates the optical microstructure 302 at the first incident angle, at least a portion of the optical anti-counterfeiting element 1 presents a second color in the direction of scattered light.

[0087] Specifically, when the units of the optical microstructure 302 are randomly or pseudo-randomly distributed in the second direction, at least a portion of the structure of the optical microstructure 302 has a feature size greater than or equal to 0.3 μm and less than or equal to 6 μm in the second direction, and a feature size greater than 6 μm in the first direction. Furthermore, the depth of at least a portion of the structure of the optical microstructure 302 also satisfies the following condition: when a light beam is incident on the optical microstructure 302 at a first incident angle, and the light beam is perpendicular to the plane where the substrate 6 is located, and the second direction is on the plane of the substrate 6, then at least a portion of the optical anti-counterfeiting element 1 presents a second color in the direction of scattered light within that plane.

[0088] Specifically, when the units of the optical microstructure 302 are periodically distributed in the first direction and randomly or pseudo-randomly distributed in the second direction, at least a portion of the structure of the optical microstructure 302 has a feature size greater than or equal to 0.3 μm and less than or equal to 6 μm in the first direction, and a feature size greater than or equal to 0.3 μm and less than or equal to 6 μm in the second direction. Furthermore, the depth of at least a portion of the structure of the optical microstructure 302 also satisfies the following: when a light beam is incident on the optical microstructure 302 at a first incident angle and the light beam is perpendicular to the plane where the substrate 6 is located, and the second direction is on the plane, then at least a portion of the optical anti-counterfeiting element 1 presents a second color in the direction of scattered light within the plane; and when a light beam is incident on the optical microstructure 302 at a first incident angle and the light beam is perpendicular to the plane where the substrate 6 is located, and the first direction is on the plane, then at least a portion of the optical anti-counterfeiting element 1 presents a +1 or -1 order diffraction color that varies with the angle in the direction of diffraction light within the plane.

[0089] It should be noted that the first and second directions mentioned above are any directions on the two-dimensional surface of the substrate 6 where the optical microstructure 302 is located.

[0090] Specifically, the optical microstructure 302 includes one or more of non-diffractive microstructures and diffractive microstructures. When the optical microstructure 302 includes a non-diffractive microstructure, the size of the non-diffractive microstructure is greater than 5 micrometers. When the optical microstructure 302 includes a diffractive microstructure, the size of the diffractive microstructure is greater than or equal to 0.1 micrometers and less than or equal to 5 micrometers.

[0091] Specifically, the optical anti-counterfeiting element 1 also includes a first functional layer located between the substrate 6 and the coding pattern 101, and a second functional layer located on the side of the coding pattern 101 away from the substrate 6. The first functional layer includes one of a release layer 8, a reinforcing layer, a protective layer, a magnetic layer, a fluorescent layer, and an infrared layer; the second functional layer includes one of a release layer 8, a reinforcing layer, a protective layer, a magnetic layer, a fluorescent layer, and an infrared layer.

[0092] like Figures 6a to 8c As shown, the optical microstructure 302 is defined such that when a light beam enters the optical microstructure 302 at a first incident angle, the light beam of a first wavelength or a first wavelength range in the light beam interferes constructively in the direction of the reflected light.

[0093] The “characteristic dimension” of the optical microstructure 302 mentioned below refers to the dimension in any direction of the contour that surrounds the protruding or concave part by dividing the surface of the optical microstructure 302 by taking the average of the lowest and highest points of its surface height.

[0094] "Unit of optical microstructure 302" refers to a single protrusion or depression formed by dividing the surface of optical microstructure 302 by taking the average of the lowest and highest points of its surface height, with its characteristic size on the order of micrometers.

[0095] The depth d of the optical microstructure 302 refers to the height difference between the highest and lowest points on the surface of the optical microstructure 302. A spatial coordinate system xyz is defined, where the xoy plane is parallel to the plane containing the optical anti-counterfeiting element 1, and the z-direction is perpendicular to this plane. For example... Figure 6a As shown, the optical microstructure 302 can be located in the xoy plane (or a plane parallel to the xoy plane), and its feature dimensions in the x-axis and y-axis directions can be greater than or equal to 0.3 μm and less than or equal to 6 μm, preferably greater than or equal to 0.6 μm and less than or equal to 3 μm. The units of the optical microstructure 302 can be randomly or pseudo-randomly distributed in the x-axis and y-axis directions. The protruding portions in the optical microstructure 302 can account for 20%-80% of the total area of ​​the optical microstructure 302, preferably 35%-65%. Figure 6b As shown, the cross-sectional shape of the unit cells of the optical microstructure 302 can be sinusoidal. For example... Figure 6c As shown, the cross-sectional shape of the unit cells of the optical microstructure 302 can be serrated. For example... Figure 6d As shown, the cross-sectional shape of the unit of the optical microstructure 302 can be rectangular. Those skilled in the art will understand that the cross-sectional shape of the unit of the optical microstructure 302 can also be other shapes. The depth d of the optical microstructure 302 can satisfy the following condition: when natural light (white light) illuminates the optical microstructure 302 at an incident angle α, after the light beam passes through the optical microstructure 302, the light with wavelength λ (or a wavelength range) undergoes constructive interference in the direction of reflected light, thereby causing the optical anti-counterfeiting element 1 to exhibit a first color when observed in the direction of reflected light, and a second color (e.g., when observed in the direction of scattered light) when observed in the direction of scattered light. Figure 6b As shown in the figure, the depth can be a preset depth.

[0096] Specifically, the depth d of the optical microstructure 302 is typically in the range of greater than or equal to 100 nm and less than or equal to 5 μm, preferably in the range of greater than or equal to 200 nm and less than or equal to 3 μm. The depth d of the optical microstructure 302 can be determined by the following method.

[0097] 1. Express the complex amplitude transmittance τ of the optical microstructure 302. g , τ g It is a function of depth d, design wavelength λ, groove shape of optical microstructure 302, material refractive index distribution n, and position (x, y);

[0098] 2. Transmittance τ of complex amplitude g Perform Fourier transform;

[0099] 3. Find the condition under which the reflected light (i.e., the zeroth-order diffraction light) with wavelength λ is maximized;

[0100] 4. Calculate the depth d based on the condition of maximum reflected light.

[0101] For example, if the design wavelength λ = 600 nm, the refractive index of the material of the optical microstructure 302 is n = 1.5, the cross-sectional shape of the optical microstructure 302 is sinusoidal, and the external medium is air, then when d = 1528.8 nm, it will appear red in the direction of reflected light and blue-green in the direction of scattered light. If d = 2668.8 nm, since the light with a wavelength of 410.8 nm also satisfies the constructive interference condition for reflected light, it will appear magenta in the direction of reflected light and green in the direction of scattered light.

[0102] like Figure 7a As shown, the optical microstructure 302 can be located in the xoy plane (or a plane parallel to the xoy plane), and the feature size of the optical microstructure 302 in the x-axis direction can be greater than 6 μm, preferably greater than 10 μm, thus the optical microstructure 302 has no diffraction effect in this direction. The feature size of the optical microstructure 302 in the y-axis direction can be in the range of greater than or equal to 0.3 μm and less than or equal to 6 μm, preferably in the range of greater than or equal to 0.6 μm and less than or equal to 3 μm, and the units of the optical microstructure 302 can be randomly or pseudo-randomly distributed. The protrusions in the optical microstructure 302 can account for 20%-80% of the total area of ​​the optical microstructure 302, preferably 35%-65%. Figure 7b As shown, the cross-sectional shape of the unit of the optical microstructure 302 in the yoz plane can be sinusoidal. However, those skilled in the art will understand that the cross-sectional shape of the unit of the optical microstructure 302 can be serrated, rectangular, or other shapes. The depth d of the optical microstructure 302 can satisfy the following condition: when natural light (white light) illuminates the optical microstructure 302 at an incident angle α, after the light beam passes through the optical microstructure 302, the light with wavelength λ (or a wavelength range) undergoes constructive interference in the direction of reflected light, thereby allowing a first color to be observed in the direction of reflected light. Furthermore, if the light beam is in the yoz plane (or a plane parallel to the yoz plane), a second color is observed in the direction of scattered light in the yoz plane (or a plane parallel to the yoz plane).

[0103] The depth d of the optical microstructure 302 is typically between 100 nm and 5 μm, preferably between 200 nm and 3 μm. The method for determining the depth d of the optical microstructure 302 is similar to... Figures 6a-6d The same implementation methods apply, so they will not be repeated here.

[0104] like Figure 8aAs shown, the optical microstructure 302 can be located in the xoy plane (or a plane parallel to the xoy plane). The feature size in the y-axis direction can be in the range of greater than or equal to 0.3 μm and less than or equal to 6 μm, preferably in the range of greater than or equal to 0.6 μm and less than or equal to 3 μm. The units of the optical microstructure 302 can be randomly or pseudo-randomly distributed. The feature size in the x-axis direction can be in the range of greater than or equal to 0.3 μm and less than or equal to 6 μm, preferably in the range of greater than or equal to 0.6 μm and less than or equal to 3 μm. The units of the optical microstructure 302 can be a periodic structure in the x-axis direction.

[0105] The protruding portion in the optical microstructure 302 can account for 20%-80% of the total area of ​​the optical microstructure 302, preferably 35%-65%. Figure 8b This is a schematic cross-sectional view of the optical microstructure 302 in the yoz plane (or a plane parallel to the yoz plane). Figure 8c This is a schematic cross-sectional view of the optical microstructure 302 in the xoz plane (or a plane parallel to the xoz plane). The cross-sectional shape of the unit of the optical microstructure 302 can be sinusoidal, sawtooth, rectangular, or other shapes. The depth d of the optical microstructure 302 can satisfy the following condition: when natural light (white light) illuminates the optical microstructure 302 at an incident angle α, after the light beam passes through the optical microstructure 302, the light with wavelength λ (or a wavelength range) undergoes constructive interference in the direction of the reflected light, thereby allowing the first color to be observed in the direction of the reflected light. Furthermore, if the light beam is in the yoz plane (or a plane parallel to the yoz plane), a second color is observed in the direction of the scattered light in the yoz plane (or a plane parallel to the yoz plane); if the light beam is in the xoz plane (or a plane parallel to the xoz plane), the color of the +1 or -1 order diffracted light of the grating is observed to change with the observation angle in the direction of the diffracted light.

[0106] At this point, the depth d of the optical microstructure 302 is typically in the range of greater than or equal to 100 nm and less than or equal to 5 μm, preferably in the range of greater than or equal to 200 nm and less than or equal to 3 μm. The method for determining the depth d of the optical microstructure 302 is similar to... Figures 6a-6d The same implementation methods apply, so they will not be repeated here.

[0107] The following is combined with Figure 9 The description pertains to the case where optical microstructure 302 is a subwavelength microstructure. For example... Figure 9 As shown, the optical microstructure 302 is a subwavelength microstructure, and a coating 402 is provided on the subwavelength microstructure. The subwavelength microstructure and the coating 402 together form a first-line public optical anti-counterfeiting feature that can be directly seen by the human eye in the direction of reflected light and its vicinity.

[0108] In a preferred embodiment of the present invention, the subwavelength microstructure is a one-dimensional grating, and the groove shape of the one-dimensional grating can be a combination of one or more of sinusoidal, rectangular, and sawtooth shapes. Alternatively, the subwavelength microstructure can also be a two-dimensional grating, and the groove shape of the two-dimensional grating includes a combination of one or more of sinusoidal, rectangular, and sawtooth shapes. Furthermore, the grating distribution of the two-dimensional grating can be an orthogonal structure, a honeycomb structure, a two-dimensional Bravais lattice structure, a random structure, etc. It should be understood that the structure of the subwavelength microstructure is not limited to the structures described above, and combinations of these structures can be used in the actual optical anti-counterfeiting element 1. By designing the subwavelength microstructure, patterns such as text and markings required for anti-counterfeiting can be realized.

[0109] Specifically, the groove depth of the subwavelength microstructure is greater than or equal to 10 nm and less than or equal to 500 nm; preferably, the groove depth of the subwavelength microstructure is greater than or equal to 50 nm and less than or equal to 300 nm; furthermore, the feature size of the subwavelength microstructure in its two-dimensional plane is greater than or equal to 50 nm and less than or equal to 500 nm; preferably, the feature size of the subwavelength microstructure in its two-dimensional plane is greater than or equal to 200 nm and less than or equal to 400 nm. However, when the feature size in one direction meets the requirements, the feature size in the other direction is not limited.

[0110] Specifically, there is a certain matching relationship between the period and the groove depth of the subwavelength microstructure. This matching relationship can be represented by the aspect ratio (i.e., the ratio of the groove depth to the period), which is designed and calculated based on the specific reproduction effect through rigorous coupled wave theory. Preferably, the aspect ratio of the subwavelength microstructure is usually in the range of greater than or equal to 0.3 and less than or equal to 2, and more preferably in the range of greater than or equal to 0.4 and less than or equal to 1.

[0111] Specifically, the coating 402 can be one or more layers. When the coating 402 is a single layer, it can be one of a metal reflective layer, a semiconductor material layer, or a dielectric layer. When the coating 402 is multilayered, it is a multilayer film, i.e., composed of different dielectric layers with high and low refractive indices. This structure typically employs a λ / 4 film system design. Moreover, the materials used for each dielectric layer can be one or more of inorganic coating materials such as MgF2, SiO2, Al2O3, MgO, HfO2, TiO2, ZnS, and ZnO. Of course, polymers or combinations of inorganic coating materials and polymers can also be used.

[0112] The structure of the multilayer plating 402 can also be a multilayer structure of metal layers or dielectric layers, typically three or five layers. For example, the structure of the multilayer plating 402 may include at least one of the following:

[0113] a. A first reflective layer formed on the optical microstructure 302, a first dielectric layer formed on the first reflective layer, and a first absorption layer formed on the first dielectric layer, wherein the order of the above three layers can be reversed;

[0114] b. A second absorption layer formed on the optical microstructure 302, a second dielectric layer formed on the second absorption layer, and a third absorption layer formed on the second dielectric layer, the order of the above three layers can be reversed;

[0115] c. A fourth absorption layer formed on the optical microstructure 302, a third dielectric layer formed on the fourth absorption layer, a second reflective layer formed on the third dielectric layer, a fourth dielectric layer formed on the second reflective layer, and a fifth absorption layer formed on the fourth dielectric layer;

[0116] d. A sixth absorption layer formed on the optical microstructure 302, a fourth dielectric layer formed on the sixth absorption layer, a seventh absorption layer formed on the fourth dielectric layer, a fifth dielectric layer formed on the seventh absorption layer, and an eighth absorption layer formed on the fifth dielectric layer.

[0117] In short, the three-layer multilayer coating 402 consists of a reflective layer, a dielectric layer, and an absorption layer, or an absorption layer, a dielectric layer, and an absorption layer. The former allows the light-changing effect to be observed from only one side, while the latter allows the light-changing effect to be observed from both sides. The five-layer multilayer coating 402 consists of an absorption layer, a dielectric layer, a reflective layer, a dielectric layer, and an absorption layer, or an absorption layer, a dielectric layer, an absorption layer, a dielectric layer, and an absorption layer. The five-layer multilayer coating 402 allows the light-changing effect to be observed from both sides. The light-changing effects observed on both sides can be designed to be the same or different, depending on the parameters and materials of each reflective layer, dielectric layer, and absorption layer.

[0118] The aforementioned reflective layer is generally a relatively thick metal layer, typically greater than 20 nm. The material used can be one or more of gold, silver, copper, aluminum, iron, tin, zinc, nickel, and chromium. The aforementioned dielectric layer can be a single-layer dielectric layer, using materials selected from inorganic coating materials such as MgF2, SiO2, Al2O3, MgO, PMMA, HfO2, TiO2, ZnS, and ZnO, as well as polymers. Its thickness is determined by the desired optical effect and the refractive index of the material, generally ranging from 10 nm to 1000 nm, preferably from 50 nm to 800 nm. Alternatively, the aforementioned dielectric layer can be a multilayer dielectric layer, using materials selected from common inorganic coating materials such as MgF2, SiO2, Al2O3, MgO, PMMA, HfO2, TiO2, ZnS, and ZnO. Multilayer dielectric layers typically employ a high-refractive-index, low-refractive-index λ / 4 film system design. The material used in the absorption layer can be one or more of the following metals or metal compounds: gold, silver, copper, aluminum, iron, tin, zinc, nickel, chromium, etc. The thickness is usually no more than 20 nm, preferably in the range of greater than or equal to 5 nm and less than or equal to 10 nm. Its function is to partially reflect, partially transmit and partially absorb the illumination light.

[0119] It should be understood that the structure of the multilayer coating 402 according to the present invention is not limited to the structure described above. For example, a two-layer structure (i.e., a reflective layer and a dielectric layer) or a four-layer structure (i.e., an absorption layer, a dielectric layer, a reflective layer, and a dielectric layer) is also desirable.

[0120] Specifically, the multilayer coating 402 forms a Fabry-Poisson resonant cavity; it selectively absorbs and reflects incident white light, so that the outgoing light contains only certain wavelengths, thus forming a specific color; when the incident angle or the outgoing angle of the light changes, the corresponding optical path changes, the interference wavelength also changes, thus causing the color presented to the observer to change accordingly, thereby forming a specific color light variation effect.

[0121] The optical characteristics obtained by combining the subwavelength microstructure with the coating 402 are specifically defined in Chinese Patent CN102514443, including their parameter matching relationship, specific principles, and optical features. In summary, the combination of the subwavelength microstructure and the coating 402 creates a color-changing feature that changes with the viewing angle, distinct from the color characteristics provided by a coating 402 with a flat or smooth surface, thus forming a unique color-changing feature that varies with the viewing angle.

[0122] For example, if the subwavelength microstructure is selected to have a sinusoidal shape, a period of 300 nm, a depth of 100 nm, and an orthogonal two-dimensional grid distribution, and the coating 402 is selected to sequentially contain Al (40 nm), SiO2 (370 nm), or Cr (5 nm) (on a flat surface, this multilayer coating 402 with these parameters has the characteristic of being golden yellow when viewed from the front and green when viewed from the side), then the subwavelength microstructure and the coating 402 will together form a red-to-yellow color characteristic.

[0123] Preferably, the subwavelength microstructure and coating 402, when used together, can also achieve polarization characteristics in or near the direction of reflected light, or transmissive observable color characteristics in the direction of transmitted light.

[0124] Through the technical solutions in the above embodiments, the optical anti-counterfeiting element 1 can achieve first-line public optical anti-counterfeiting features such as holographic diffraction characteristics, reflection characteristics, interference characteristics, scattering characteristics, and light variation characteristics in or near the direction of reflected light by controlling the type and parameters of the optical microstructure 302 of the second part 202 in combination with the coating 402 on its surface. Furthermore, by controlling the feature size of the first part 201, the transmitted light flux of the first part 201 can be controlled. The encoded pattern 101 reproduces the pre-set information through decoding, and the brightness of the encoded pattern 101 can be arbitrarily adjusted by the transmitted light flux, allowing the transmitted light to be received by the naked eye without causing burns, protecting the user's health. This enables direct observation with the naked eye, eliminating the need to receive pre-set information through a screen, thus achieving a more easily identifiable second-line hidden anti-counterfeiting feature and increasing anti-counterfeiting effectiveness.

[0125] like Figure 10 As shown, an exemplary method for manufacturing the optical anti-counterfeiting element 1 of the present invention is provided.

[0126] (1) A coding pattern 101 is formed on the surface of the substrate 6 using thermoplastic material and molding process. The coding pattern 101 is a Fourier transform pattern obtained by computer calculation, and its pre-set two-line anti-counterfeiting hidden pattern information is a graphic "hexagonal star".

[0127] The first part 201 of the coding pattern 101 has an average linewidth of 1 micrometer, meaning its feature size is 1 micrometer. The second part 202 has an average linewidth greater than 1 micrometer, ensuring that the second part 202 occupies a larger area of ​​the coding pattern 101 than the first part 201. The first part 201 of the coding pattern 101 contains a one-dimensional sinusoidal submicron grating structure with a depth of 500 nm and a width of 250 nm. The second part 202 contains a sawtooth blazed grating with a slope of 0–1 and an azimuth angle of 0–360°. The blazed gratings are arranged in a pre-designed manner throughout the second part 202. The microstructure of the coding pattern 101 is obtained through electron beam etching, and a metal master is formed through electroforming. The molding material and process are then used to complete the batch molding replication of the coding pattern 101 on the surface of the substrate 6.

[0128] (2) A coating 402 is set on the surface of the coding pattern 101. Specifically, an Al layer with a thickness of 50 nm is deposited on the surface of the coding pattern 101. Then, the entire structure is immersed in an acid pickling environment, typically using a phosphoric acid solution to etch the Al layer. Since the microstructure depth-to-width ratio of the first part 201 is higher than that of the second part 202, the thickness of the Al layer on the first part 201 is smaller than that on the second part 202. During the acid pickling process, the Al layer of the first part 201 is completely etched and dissolved, while the Al layer of the second part 202 still retains a thickness of 30 nm.

[0129] (3) An adhesive layer 7 is applied to the upper surface of the coding pattern 101. The adhesive layer 7 is a transparent UV coating with a refractive index that is less than 0.2 different from the refractive index of the molding material, thereby ensuring that the first part 201 is transparent.

[0130] At this point, under the illumination of the phone's point light source, Figure 10 The optical anti-counterfeiting element 1 in the middle can provide a clear, moderately bright "hexagonal star" two-line hidden reproduction image, and provide a clear first-line mass-market optical anti-counterfeiting feature with a non-diffraction pattern contributed by the second part 202 in the absence of a point light source.

[0131] In the above manufacturing process, the first part 201 and the second part 202 are never introduced and there is no alignment error. That is, the position and appearance of the optical microstructure 302 of the second part 202 are connected or spliced ​​together with the position and appearance of the first part 201 at the micron-level microscale without error. This is something that existing printed perforated coating 402 technology and products cannot achieve. Existing printed perforated coating 402 technology and products have two defects: first, they cannot form a printing stroke width of less than 10μm, which makes it impossible to form the feature size of the first part 201 of no more than 5μm, affecting the quality of the second-line reproduction hidden feature; second, they cannot form a printing registration accuracy of 10μm, which makes it impossible to guarantee that the optical microstructure 302 of the second part 202 cannot be arbitrarily designed or have defects, affecting the quality of the first-line public optical anti-counterfeiting feature. The optical anti-counterfeiting element 1 of the present invention can provide the reproduction hidden feature of the first part 201 while providing almost 100% of the part other than the first part 201 to the first-line public optical anti-counterfeiting feature without wasting space.

[0132] In practical applications, through optimized design, as the feature size of the first part 201 decreases (not exceeding 5μm), its proportion in the coded pattern 101 decreases until its presence is imperceptible to the naked eye. At this point, the first-line anti-counterfeiting feature provided by the second part 202 is no less effective than the existing first-line anti-counterfeiting feature provided only by the optical microstructure 302 and the coating 402. Furthermore, due to the second-line concealment feature provided by the first part 201, existing counterfeiting methods that merely imitate the first-line anti-counterfeiting feature of the second part 202 without simultaneously providing the second-line concealment feature are effectively curbed.

[0133] More specifically, the information pre-set in the coded pattern 101 and the first-line optical anti-counterfeiting feature information provided in the second part 202 are associated and interact with each other, and are precisely aligned, thereby forming a new integrated optical anti-counterfeiting feature. This is also a more unique structural form of the optical anti-counterfeiting element 1 disclosed in this invention.

[0134] like Figure 11As shown, (a) shows a top view of the encoded pattern 101, where the cross-sectional view of the optical anti-counterfeiting element 1 and the specific distribution of the first part 201 and the second part 202 in the encoded pattern 101 are omitted here; the preset two-line hidden optical pattern is provided by the first part 201, and the one-line public optical anti-counterfeiting feature is provided by the second part 202; as shown in (b), under the illumination of reflected light, the second part 202 adopts a snowflake pattern with a three-dimensional relief texture provided by a Fresnel diffraction structure and a multi-layer interference coating 402; as shown in (c), on the back of the encoded pattern 101, under the illumination of transmitted light perpendicular to the direction of the "snowflake pattern with a three-dimensional relief texture", the first part 201 will provide the preset reproduced hidden information "*"; as shown in (d), in an environment with both transmitted light and reflected light, the user can simultaneously see the "snowflake pattern with a three-dimensional relief texture" and the reproduced hidden information "*", and the two are strictly at the same central position and overlap with each other.

[0135] As Figure 12 shown, (a) shows a top view of the encoded pattern 101, where the cross-sectional view of the optical anti-counterfeiting element 1 and the specific encoding distribution of the first part 201 and the second part 202 in the encoded pattern 101 are omitted here; the preset two-line hidden optical pattern is provided by the first part 201, and the one-line public optical anti-counterfeiting feature is provided by the second part 202; as shown in (b), under the illumination of reflected light, the second part 202 adopts a "Fu" character pattern with rainbow features provided by a periodic rainbow holographic grating structure and an aluminum coating 402; as shown in (c), on the back of the encoded pattern 101, under the illumination of transmitted light perpendicular to the direction of the "Fu" pattern, the first part 201 will provide the preset reproduced hidden information "lantern"; as shown in (d), in an environment with both transmitted light and reflected light, the user can simultaneously see the "Fu" pattern and the reproduced hidden information "lantern", and the two are strictly at the same central position and overlap with each other.

[0136] In Figure 11 、 Figure 12 the specific embodiments given, when the light source conditions change, the position of the hidden pattern information of the corresponding encoded pattern 101 may change, but it does not affect the precise alignment relationship between the hidden pattern information and the one-line public optical anti-counterfeiting image.

[0137] The present invention also provides an anti-counterfeiting product, and the anti-counterfeiting product includes the above-mentioned optical anti-counterfeiting element 1. The optical anti-counterfeiting element 1 of the present invention can be transferred or pasted onto a carrier in the form of marking, hot stamping a wide strip, pasting a strip, etc. These carriers can be high-security products such as banknotes, securities, credit cards, passports, or high-value-added commodities.

[0138] Obviously, the embodiments described above are merely some, not all, embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0139] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0140] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0141] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An optical anti-counterfeiting element, characterized in that, include: Substrate (6); The coded pattern (101) is provided on at least a portion of one side surface of the substrate (6). The coded pattern (101) reproduces pre-set information through decoding. The coded pattern (101) includes a first part (201) and a second part (202). The first part (201) and the second part (202) are interlocked. The first part (201) is transparent and at least a local feature size of the first part (201) is no greater than 5 μm. The second part (202) includes an optical microstructure (302) and a coating (402) that conformally covers the side surface of the optical microstructure (302) away from the substrate (6). When a light beam is incident on the first part (201) and the second part (202), the second part (202) provides a line optical anti-counterfeiting feature visible to the human eye in and around the direction of the reflected light. The first part (201) generates a transmitted light field and the transmitted light field reproduces the pre-set information.

2. The optical anti-counterfeiting element according to claim 1, characterized in that, The projected area of ​​the second part (202) on the substrate (6) is greater than the projected area of ​​the first part (201) on the substrate (6).

3. The optical anti-counterfeiting element according to claim 1, characterized in that, The first part (201) and the second part (202) are spliced ​​together to form the entire coded pattern (101).

4. The optical anti-counterfeiting element according to claim 1, characterized in that, The encoding pattern (101) is one of the transformation patterns of Fourier transform pattern, Fresnel transform pattern, Moiré encoding pattern (101), barcode, QR code, Hilbert transform pattern, Abel transform pattern, and Merlin transform pattern.

5. The optical anti-counterfeiting element according to claim 1, characterized in that, The optical microstructure (302) is defined such that when a light beam enters the optical microstructure (302) at a first incident angle, the light beam of a first wavelength or a first wavelength range in the light beam is constructively interfered in the direction of reflected light, and at least a portion of the structure of the optical microstructure (302) has a preset depth so that at least a portion of the optical anti-counterfeiting element presents a first color in the direction of reflected light.

6. The optical anti-counterfeiting element according to claim 5, characterized in that, The pattern of at least a portion of the optical microstructure (302) is at least one of the following or a combination of at least two of the following: The units of the optical microstructure (302) are randomly or pseudo-randomly distributed in both the first and second directions; The units of the optical microstructure (302) are periodically distributed in the first direction and randomly or pseudo-randomly distributed in the second direction. The units of the optical microstructure (302) are randomly or pseudo-randomly distributed only in the second direction.

7. The optical anti-counterfeiting element according to claim 1, characterized in that, When the units of the optical microstructure (302) are randomly or pseudo-randomly distributed in both the first and second directions, the feature size of at least a portion of the optical microstructure (302) is greater than or equal to 0.3 μm and less than or equal to 6 μm, and the depth of at least a portion of the optical microstructure (302) satisfies: When the light beam illuminates the optical microstructure (302) at a first incident angle, at least a portion of the optical anti-counterfeiting element exhibits a second color in the direction of the scattered light.

8. The optical anti-counterfeiting element according to claim 1, characterized in that, When the units of the optical microstructure (302) are randomly or pseudo-randomly distributed in the second direction, at least a portion of the optical microstructure (302) has a feature size greater than or equal to 0.3 μm and less than or equal to 6 μm in the second direction, a feature size greater than 6 μm in the first direction, and the depth of at least a portion of the optical microstructure (302) also satisfies: When the light beam is incident on the optical microstructure (302) at a first incident angle and the light beam is perpendicular to the plane where the substrate (6) is located, and the second direction is on the plane, at least a portion of the optical anti-counterfeiting element presents a second color in the direction of scattered light in the plane.

9. The optical anti-counterfeiting element according to claim 1, characterized in that, When the units of the optical microstructure (302) are periodically distributed in a first direction and randomly or pseudo-randomly distributed in a second direction, at least a portion of the optical microstructure (302) has a feature size greater than or equal to 0.3 μm and less than or equal to 6 μm in the first direction, and a feature size greater than or equal to 0.3 μm and less than or equal to 6 μm in the second direction, and the depth of at least a portion of the optical microstructure (302) also satisfies: When the light beam is incident on the optical microstructure (302) at a first incident angle, and the light beam is perpendicular to the plane containing the substrate (6), and the second direction is on the plane, at least a portion of the optical anti-counterfeiting element exhibits a second color in the direction of scattered light within the plane; and / or When the light beam is incident on the optical microstructure (302) at a first incident angle and the light beam is perpendicular to the plane where the substrate (6) is located, and the first direction is on the plane, at least a portion of the optical anti-counterfeiting element exhibits a diffraction color that varies with the angle by +1 or -1 order in the diffraction direction within the plane.

10. The optical anti-counterfeiting element according to claim 1, characterized in that, The optical microstructure (302) is a subwavelength microstructure.

11. The optical anti-counterfeiting element according to claim 10, characterized in that, The subwavelength microstructure is a one-dimensional grating, and the groove shape of the one-dimensional grating includes one or more of sinusoidal, rectangular, and sawtooth shapes; or The subwavelength microstructure is a two-dimensional grating, and the groove shape of the two-dimensional grating includes one or more of sinusoidal, rectangular, and sawtooth shapes.

12. The optical anti-counterfeiting element according to claim 10, characterized in that, The groove depth of the subwavelength microstructure is greater than or equal to 10 nm and less than or equal to 500 nm; and / or The subwavelength microstructure has a feature size greater than or equal to 50 nm and less than or equal to 500 nm in its two-dimensional plane.

13. The optical anti-counterfeiting element according to claim 10, characterized in that, The groove depth of the subwavelength microstructure is greater than or equal to 50 nm and less than or equal to 300 nm; and / or The subwavelength microstructure has a feature size greater than or equal to 200 nm and less than or equal to 400 nm in its two-dimensional plane.

14. The optical anti-counterfeiting element according to claim 1, characterized in that, The optical microstructure (302) includes one or more of non-diffractive and diffractive microstructures. When the optical microstructure (302) includes the non-diffraction microstructure, the size of the non-diffraction microstructure is greater than 5 micrometers; When the optical microstructure (302) includes the diffraction microstructure, the size of the diffraction microstructure is greater than or equal to 0.1 micrometers and less than or equal to 5 micrometers.

15. The optical anti-counterfeiting element according to claim 1, characterized in that, The optical anti-counterfeiting element further includes a first functional layer located between the substrate (6) and the coding pattern (101), and / or a second functional layer located on the side of the coding pattern (101) away from the substrate (6). The first functional layer includes one of the following: a release layer (8), a reinforcement layer, a protective layer, a magnetic layer, a fluorescent layer, and an infrared layer; The second functional layer includes one of the following: a release layer (8), a reinforcement layer, a protective layer, a magnetic layer, a fluorescent layer, and an infrared layer.

16. The optical anti-counterfeiting element according to claim 1, characterized in that, The coating (402) is one or more layers. When the coating (402) is multiple layers, the multiple coating layers (402) form a Fabry-Poisson resonant cavity.

17. The optical anti-counterfeiting element according to claim 1, characterized in that, The proportion of transmitted light in the first part (201) is more than 10% higher than that in the second part (202).

18. The optical anti-counterfeiting element according to claim 1, characterized in that, The proportion of transmitted light in the first part (201) is more than 20% higher than that in the second part (202).

19. The optical anti-counterfeiting element according to claim 1, characterized in that, The substrate (6) is a polyvinyl chloride (PVC) board, a polyethylene terephthalate (PET) board, a polycarbonate (PC) board, or a glass board.

20. An anti-counterfeiting product, characterized in that, The anti-counterfeiting product includes the optical anti-counterfeiting element (1) as described in any one of claims 1 to 19.

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