Optical anti-counterfeiting file and preparation method thereof

Abstract

The invention relates to the technical field of anti-counterfeiting, and discloses an optical anti-counterfeiting file and a preparation method thereof. The optical anti-counterfeiting file comprises a base material, a first microstructure layer and a second microstructure layer, wherein the base material is provided with a first surface and a second surface which are opposite to each other; the first microstructure layer is arranged on the first surface, a plurality of spaced first grooves are formed in the surface of the side, away from the base material, of the first microstructure layer, and the first grooves are provided with first filling layers to form grating structures; the second microstructure layer is arranged on the second surface, a second groove is formed in the surface of the side, away from the base material, of the second microstructure layer, and a second filling layer is arranged in the second groove to form a micro image-text structure; the grating structure and the micro image-text structure are correspondingly arranged relative to the base material so as to be matched to form a gradient pattern. The grating structure and the micro image-text structure are matched to form a clear and bright gradient pattern, a dynamic change effect is presented at different angles, strict control over the thickness of the base material is not needed, the manufacturing difficulty of the anti-counterfeiting file is reduced, and high-quality optical imaging and a visual effect are guaranteed.

Description

Technical Field

[0001] The present invention relates to the field of anti-counterfeiting technology, and in particular to an optical anti-counterfeiting document and a preparation method thereof. Background Art

[0002] Optical anti-counterfeiting elements are widely used in high-security products such as banknotes, credit cards, passports and securities, as well as other high-value-added products, due to their unique visual effects and easy recognition. In the field of optical anti-counterfeiting, optical anti-counterfeiting documents will show different visual pattern changes or color changes at different angles. When the observer changes the viewing angle, such as tilting the optical anti-counterfeiting element, or changing the illumination direction of the light source, or changing the observer's viewing direction, the visual pattern or color of the optical anti-counterfeiting element will change. This change is easy and fast to identify.

[0003] There are many ways for optical anti-counterfeiting documents to have the above-mentioned identification features. In the related lens products, the three-dimensional and dynamic effects are generally formed through the interaction of the lens array and the micro-image array through moiré magnification. For example, the microlens array is provided with periodically arranged hemispherical ball lenses or semi-cylindrical column lenses. The two surfaces of the optical anti-counterfeiting document substrate are respectively provided with a microlens array and a micro-image array. The moiré magnification effect of the microlens array on the micro-image array is used to reproduce a pattern with a certain depth of field or present a dynamic effect. However, for optical anti-counterfeiting elements of this structure, on the one hand, since the microlens element has a focal length, it is necessary to arrange the micro-image near the focus of the microlens, and it is necessary to strictly control the thickness of the substrate to obtain a clear moiré magnified image; on the other hand, the protruding microlenses are exposed to the outside and are easily contaminated and fail, and the magnified observation of the image is difficult to guarantee. Summary of the invention

[0004] In view of this, the present invention provides an optical anti-counterfeiting document and a preparation method thereof to solve the problem that the existing optical anti-counterfeiting document needs to strictly control the thickness of the substrate and the imaging quality is difficult to ensure.

[0005] In the first aspect, the present invention provides an optical anti-counterfeiting document, comprising: a substrate, a first microstructure layer and a second microstructure layer, the substrate having a first surface and a second surface relative to each other; the first microstructure layer is arranged on the first surface; a plurality of spaced first grooves are formed on the surface of the first microstructure layer on the side facing away from the substrate, a first filling layer is arranged in the first groove to form a grating structure, the first filling layer is a pigment or an enhanced reflection material; the second microstructure layer is arranged on the second surface; a second groove is formed on the surface of the second microstructure layer on the side facing away from the substrate, a second filling layer is arranged in the second groove to form a micro-image structure, the second filling layer is a pigment or an enhanced reflection material; the grating structure and the micro-image structure are arranged correspondingly relative to the substrate to cooperate to form a gradient pattern.

[0006] Beneficial effects: The optical anti-counterfeiting document forms a clear and bright gradient pattern of moiré magnification through the combination of grating structure and micro-graphic structure, presenting a dynamic changing effect at different angles to achieve an anti-counterfeiting effect; since there is no focusing lens structure, there is no concept of "focal length" and "focus", so there is no need to strictly control parameters such as lens morphology and substrate thickness, which reduces the difficulty of making anti-counterfeiting documents. The grooved grating structure also reduces the risk of contamination to a certain extent, ensuring high-quality optical imaging and visual effects.

[0007] In an optional embodiment, the material of the first filling layer is a pigment, the material of the second filling layer is an enhanced reflection material, and one side of the first filling layer is an observation side.

[0008] In the present invention, when an observer observes from the first microstructure layer from top to bottom, the high reflectivity of the second filling layer's enhanced reflective material to light enhances the brightness of the color image of the grating structure, achieving a strong pattern contrast effect, a clear and obvious color gradient pattern, and a gradient from orange to white. In addition, as the optical anti-counterfeiting document is tilted at different angles, the color gradient pattern of the micro-image area also presents a dynamic change effect, which reduces the difficulty of making anti-counterfeiting documents, ensures high-quality optical imaging and visual effects, and improves anti-counterfeiting performance.

[0009] In an optional embodiment, the material of the first filling layer is a reflection enhancing material, the material of the second filling layer is a pigment, and one side of the second filling layer is an observation side.

[0010] In the present invention, when an observer observes from the side where the pigment is located, the high reflectivity of the enhanced reflective material of the first filling layer to light enhances the brightness of the color image of the micro-graphic structure, achieving a strong pattern contrast effect, a clear and obvious color gradient pattern, and a gradient from orange to white. In addition, as the optical anti-counterfeiting document is tilted at different angles, the color gradient pattern of the micro-graphic area also presents a dynamic change effect, which reduces the difficulty of making the anti-counterfeiting document, ensures high-quality optical imaging and visual effects, and improves the anti-counterfeiting performance.

[0011] In an optional embodiment, the material of the first filling layer and the material of the second filling layer are both pigments, and the side where the first filling layer is located or the side where the second filling layer is located is the observation side.

[0012] In the present invention, taking the example of an observer observing from the top to the bottom on the side where the grating structure is located, the first filling layer and the second filling layer are both pigments, the color of the pattern received by the observer is obvious, and the color gradient pattern presents a gradient from orange to white. In addition, as the optical anti-counterfeiting document is tilted at different angles, the color gradient pattern of the micro-image area also presents a dynamic change effect, which reduces the difficulty of making the anti-counterfeiting document, ensures high-quality optical imaging and visual effects, and improves the anti-counterfeiting performance.

[0013] In an optional embodiment, the material of the first filling layer and the material of the second filling layer are both enhanced reflection materials, and the side where the first filling layer is located or the side where the second filling layer is located is the observation side.

[0014] In the present invention, an observer observes from one side of the optical anti-counterfeiting document with enhanced reflective material. Both the first filling layer and the second filling layer are enhanced reflective materials. The formed pattern has high brightness, and the color gradient pattern presents a gradient from silver-white to transparent. The subsequent color coating can achieve an effect of obvious pattern color and high brightness.

[0015] In an optional embodiment, a characteristic microstructure is further formed on the surface of the second microstructure layer facing away from the substrate, and a third filling layer is further arranged on the characteristic microstructure;

[0016] The characteristic microstructure includes one or more of a holographic grating, a Fresnel relief grating, a sub-wavelength microstructure unit, a reflective blazed grating, a flat surface, a printed pattern, an ink coating, a fluorescent material coating, a magnetic material coating, a phosphorus material coating or a selectively absorbent micro-nanostructure.

[0017] In an optional embodiment, the enhanced reflection material is one or more of a single dielectric layer, a multi-layer dielectric layer, a metal reflection structure, and a metal / dielectric stack.

[0018] In an optional embodiment, the substrate thickness is H1;

[0019] In the arrangement direction of the grating structure, the width of the area between two adjacent first grooves and the width of the first groove on either side thereof form a characteristic size L1 of the grating structure, and the characteristic size range of the grating structure is: 0.1 μm to H1;

[0020] In the micro-graphic structure, the width of the area between two adjacent second grooves and the width of the second groove on either side thereof form a characteristic width L2 of the micro-graphic structure, and the characteristic width range of the micro-graphic structure is: 0.1 μm to H1.

[0021] In the present invention, the characteristic size of the grating structure and the width size of the micro-graphic structure are limited to ensure that the grating structure and the micro-graphic structure can cooperate to produce high-quality dynamic features that are easy to observe.

[0022] In an optional embodiment, the thickness of the substrate is in the range of: H1≤50 μm.

[0023] In the present invention, the thickness range of the substrate is set to: H1≤50μm, which can present the preset dynamic characteristics and can be easily identified by the public. It is convenient for optical anti-counterfeiting documents to be applied to security threads. When the thickness of the security thread does not exceed 50μm, the security thread can ensure the flatness of the paper and the quality of the image of the subsequent printed product.

[0024] In an optional embodiment, the total area of ​​the first grooves accounts for 10% to 90% of the total area of ​​the grating structure;

[0025] The total area of ​​the second grooves accounts for 10% to 90% of the total area of ​​the micro-graphic structure.

[0026] In the present invention, the proportion of the total area of ​​the first grooves to the total area of ​​the grating structure and the proportion of the total area of ​​the second grooves to the total area of ​​the micro-graphic structure are limited to ensure the formation of two color gradients with similar color intensities.

[0027] In an optional embodiment, the surface of the groove where the enhanced reflection material is located, which is close to the substrate, is a diffuse reflection surface.

[0028] In the present invention, the diffuse reflection surface can more efficiently utilize incident light from different directions, and can also more efficiently illuminate other locations.

[0029] In an optional implementation, the grating structure is a periodic array and / or a non-periodic array and / or a random array and / or a partially periodic array composed of a plurality of grating units.

[0030] In an optional embodiment, it further includes: a protective layer, which is arranged on the surface of the first microstructure layer and / or the second microstructure layer facing away from the substrate, and the protective layer is a transparent coating or a semi-transparent coating.

[0031] In the present invention, the transparent protective layer avoids affecting the performance of the optical anti-counterfeiting feature, and at the same time can be bonded to paper, plastic, etc. to play a protective role, solving the problems of bonding firmness and circulation resistance.

[0032] In an optional embodiment, it further includes: an isolation reflection layer, which is arranged on a surface of the first microstructure layer or the second microstructure layer facing away from the substrate, and the side opposite to the isolation reflection layer is an observation side.

[0033] In the present invention, the isolation reflective layer effectively solves the light leakage problem, improves the color contrast of the optical anti-counterfeiting element, and achieves better recognition.

[0034] In an optional embodiment, it further includes: a magnetic encoding structure, which is arranged on a surface of the isolation reflective layer facing away from the substrate.

[0035] In the present invention, the optical anti-counterfeiting document integrates magnetic machine-readable features and dynamic features to improve the anti-counterfeiting capability.

[0036] In a second aspect, the present invention provides a method for preparing an optical anti-counterfeiting document, comprising:

[0037] Providing a substrate having a first surface and a second surface opposite to each other;

[0038] forming a first microstructure layer on a first surface of the substrate;

[0039] Forming a plurality of first grooves spaced apart from each other on a surface of the first microstructure layer facing away from the substrate;

[0040] A first filling layer is arranged in the first groove to form a grating structure, wherein the first filling layer is a pigment or a reflection enhancing material;

[0041] forming a second microstructure layer on the second surface of the substrate;

[0042] Forming a second groove on a surface of the second microstructure layer facing away from the substrate;

[0043] A second filling layer is arranged in the second groove to form a micro-image structure, and the second filling layer is a pigment or a reflection-enhancing material.

[0044] In an optional embodiment, after the second filling layer is arranged in the second groove to form the micro-graphic structure, the method further includes:

[0045] Forming an isolation reflection layer on the surface of the first microstructure layer or the second microstructure layer facing away from the substrate;

[0046] A magnetic encoding structure is arranged on the surface of the isolation reflective layer on the side facing away from the substrate;

[0047] A protective layer is formed on the surface of the second microstructure layer and / or the first microstructure layer facing away from the substrate. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0049] Figure 1 Schematic diagram of the cross-sectional structure of the optical anti-counterfeiting document of Example 1 of the present invention;

[0050] Figure 2 The image is observed when the optical anti-counterfeiting document is tilted 30° to the left in Example 1 of the present invention;

[0051] Figure 3 The image is observed when the optical anti-counterfeiting document is tilted 10° to the left in Example 1 of the present invention;

[0052] Figure 4 The image is observed when the optical anti-counterfeiting document is tilted 10° to the right in Example 1 of the present invention;

[0053] Figure 5 The image is observed when the optical anti-counterfeiting document is tilted 30° to the right in Example 1 of the present invention;

[0054] Figure 6 This is a schematic cross-sectional structure diagram of an optical anti-counterfeiting document having a protective layer, an isolation reflective layer and a magnetic encoding structure according to Embodiment 1 of the present invention;

[0055] Figure 7 Schematic diagram of the cross-sectional structure of an optical anti-counterfeiting document according to Embodiment 2 of the present invention;

[0056] Figure 8 The image is observed when the optical anti-counterfeiting document is tilted 30° to the left in Example 2 of the present invention;

[0057] Fig. 9 The image is observed when the optical anti-counterfeiting document is tilted 10° to the left in Example 2 of the present invention;

[0058] Fig.10 The image is observed when the optical anti-counterfeiting document is tilted 10° to the right in Example 2 of the present invention;

[0059] Fig.11 The image is observed when the optical anti-counterfeiting document is tilted 30° to the right in Example 2 of the present invention;

[0060] Fig.12 is another schematic cross-sectional structure diagram of the optical anti-counterfeiting document of Embodiment 2 of the present invention;

[0061] Fig.13 This is a schematic cross-sectional structure diagram of an optical anti-counterfeiting document having a protective layer, an isolation reflective layer and a magnetic encoding structure according to Embodiment 3 of the present invention;

[0062] Fig.14 The image is the image observed from the front when the optical anti-counterfeiting document is tilted 30° to the left in Example 3 of the present invention;

[0063] Fig.15 The image is the image observed from the front when the optical anti-counterfeiting document is tilted 10° to the left in Example 3 of the present invention;

[0064] Fig.16 The image is the image observed from the front when the optical anti-counterfeiting document is tilted 10° to the right in Example 3 of the present invention;

[0065] Fig.17 The image is the image observed from the front when the optical anti-counterfeiting document is tilted 30° to the right in Example 3 of the present invention;

[0066] Fig.18 The image is the image observed from the back of the optical anti-counterfeiting document tilted 30° to the left in Example 3 of the present invention;

[0067] Fig.19 The image is the image observed from the back of the optical anti-counterfeiting document tilted 10° to the left in Example 3 of the present invention;

[0068] Fig. 20 The image is the image observed from the back of the optical anti-counterfeiting document tilted 10° to the right in Example 3 of the present invention;

[0069] Fig.21 The image is the image observed from the back of the optical anti-counterfeiting document tilted 30° to the right in Example 3 of the present invention;

[0070] Fig. 22 This is a schematic cross-sectional structure diagram of an optical anti-counterfeiting document having a protective layer, an isolation reflective layer and a magnetic encoding structure according to Embodiment 3 of the present invention;

[0071] Fig.23 Schematic diagram of the cross-sectional structure of an optical anti-counterfeiting document according to Embodiment 4 of the present invention;

[0072] Fig.24 The image is observed when the optical anti-counterfeiting document is tilted 30° to the left in Example 4 of the present invention;

[0073] Fig.25 The image is observed when the optical anti-counterfeiting document is tilted 10° to the left in Example 4 of the present invention;

[0074] Fig.26 The image is observed when the optical anti-counterfeiting document is tilted 10° to the right in Example 4 of the present invention;

[0075] Fig. 27 The image is observed when the optical anti-counterfeiting document is tilted 30° to the right in Example 4 of the present invention;

[0076] Fig.28 This is a schematic cross-sectional structure diagram of an optical anti-counterfeiting document having a protective layer, an isolation reflective layer and a magnetic encoding structure according to Embodiment 4 of the present invention;

[0077] Description of reference numerals:

[0078] A. Color gradient pattern; B. Embossed hemispherical pattern; C. Digital pattern;

[0079] 1. substrate; 11. first surface; 12. second surface;

[0080] 2. first microstructure layer; 2a. grating region; 21. first groove; 22. first filling layer; 23. grating structure;

[0081] 3. Second microstructure layer; 3a. Micro-graphic area; 3b. Integrated area; 31. Second groove; 32. Second filling layer; 33. Micro-graphic structure; 34. Characteristic microstructure; 341. Blazed grating; 342. Holographic grating; 35. Third filling layer;

[0082] 4. Protective layer;

[0083] 5. Isolate the reflective layer;

[0084] 6. Magnetic coding structure. DETAILED DESCRIPTION

[0085] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only some structures related to the present invention are shown in the accompanying drawings, rather than all structures. In the following description, the description of known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention. Various structural schematic diagrams according to embodiments of the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified for the purpose of clear expression, and some details may be omitted. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships between them are only exemplary, and may be deviated due to manufacturing tolerances or technical limitations in practice, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs. In the context of the present invention, when a layer / element is referred to as being "on" another layer / element, the layer / element may be directly on the other layer / element, or there may be an intermediate layer / element between them. In addition, if one layer / element is "on" another layer / element in one orientation, then when the orientation is reversed, the layer / element may be "below" the other layer / element.

[0086] Optical anti-counterfeiting elements are widely used in high-security products such as banknotes, credit cards, passports and securities, as well as other high-value-added products due to their unique visual effects and easy recognition. Optical anti-counterfeiting documents will show different visual pattern changes or color changes at different angles. Observers can easily and quickly obtain such changing pattern or color information to achieve anti-counterfeiting identification of documents.

[0087] In the related art, optical anti-counterfeiting documents usually set microlens arrays and micro-image arrays on the two surfaces of the substrate, respectively, to form three-dimensional, dynamic patterns or color effects through the coordinated moiré magnification effect. Among them, the microlens array is usually a periodically arranged hemispherical ball lens or a semi-cylindrical column lens, but this convex microlens structure, on the one hand, due to the characteristics of lens imaging, it is necessary to place the micro-image near the focus of the microlens to obtain a clear image, so it is necessary to strictly control the thickness of the substrate to obtain a clear moiré magnification image, and the process complexity is high; on the other hand, the convex microlens is exposed to the outside, which is easy to be contaminated with oil and other substances, resulting in blurred imaging and failure, and the quality of the moiré magnification image is difficult to guarantee. Furthermore, in the related field, there is also a protective glue covering the in-place lens to prevent the lens from being contaminated, but this protective glue requires a high refractive index material similar to the refractive index of the oil, and this high refractive index material is usually expensive, and the added protective glue also needs to be strictly controlled in thickness to ensure that it does not affect the convergent imaging of the microlens, which is obviously more difficult to prepare.

[0088] Or for some reflective structures, the microlens array and the micro-image array are overlapped and made on one side of the substrate of the optical anti-counterfeiting element, that is, the microlens array and the micro-image array are located on the same side of the substrate, and the other side of the substrate is coated with a reflective layer. The position of the virtual image formed by the micro-image array through the reflective layer is located near the focal plane of the microlens array, so that the microlens array images the adjacent micro-image array through the reflective layer on the other side of the substrate. However, due to the presence of the focusing lens, there is the above-mentioned problem of strict requirements on the thickness of the substrate. In addition, while this type of reflective focusing structure is forming a moiré image of the micro-image array, light from other directions will form another image on the reflective focusing structure, and this image will also interfere with observation to a certain extent.

[0089] Therefore, the present invention provides an optical anti-counterfeiting document and a preparation method thereof, the optical anti-counterfeiting document comprising a substrate 1, a first microstructure layer 2 and a second microstructure layer 3 respectively arranged on opposite side surfaces of the substrate 1; a plurality of spaced first grooves 21 are formed on a surface of the first microstructure layer 2 facing away from the substrate 1, a first filling layer 22 is arranged in the first groove 21 to form a partially light-transmitting grating structure 23; a second groove 31 is formed on a surface of the second microstructure layer 3 facing away from the substrate 1, a second filling layer 32 is arranged in the second groove 31 to form a partially light-transmitting micro-image structure 33 with a specific image, the grating structure 23 and the micro-image structure 33 are arranged correspondingly relative to the substrate 1, and a moiré magnified image formed by the two will appear as a gradient pattern when it finally reaches the observer due to the visual deviation of the observer's eyes, and when the optical anti-counterfeiting document is tilted, the generated gradient pattern will show dynamic changes in a preset manner. Such an optical anti-counterfeiting document forms a moiré magnification image through the cooperation of the grating structure 23 and the micro-image structure 33. No focusing lens structure is set, so there is no concept of "focal length" and "focus". There is no need to strictly control parameters such as lens morphology and substrate 1 thickness, which reduces the difficulty of making anti-counterfeiting documents. The grooved grating structure 23 also reduces the risk of contamination to a certain extent, ensuring high-quality optical imaging and visual effects.

[0090] Example 1

[0091] like Figures 1 to 6 As shown, this embodiment provides an optical anti-counterfeiting document, including a substrate 1, a first microstructure layer 2 and a second microstructure layer 3. The substrate 1 has a first surface 11 and a second surface 12 opposite to each other; the first microstructure layer 2 is arranged on the first surface 11, and a plurality of spaced first grooves 21 are formed on the surface of the first microstructure layer 2 on the side away from the substrate 1, and a first filling layer 22 is arranged in the first groove 21 to form a grating structure 23, and the material of the first filling layer 22 is a pigment; the second microstructure layer 3 is arranged on the second surface 12, and a second groove 31 is formed on the surface of the second microstructure layer 3 on the side away from the substrate 1, and a second filling layer 32 is arranged in the second groove 31 to form a micro-graphic structure 33, and the material of the second filling layer 32 is an enhanced reflection material; the grating structure 23 and the micro-graphic structure 33 are arranged correspondingly relative to the substrate 1 to cooperate to form a pattern with a color gradient. The side where the first filling layer 22 is located is the observation side, that is, the observer observes from the side of the first filling layer 22 from top to bottom.

[0092] In the above optical anti-counterfeiting document, the substrate 1, the first microstructure layer 2 and the second microstructure layer 3 are all transparent or semi-transparent. Figure 1As shown, relative to the substrate 1, the outer side surface of the first microstructure layer 2 is concavely formed with a plurality of first grooves 21, and the first grooves 21 are filled with pigments as the first filling layer 22 to form a partially light-transmitting grating structure 23, that is, the first microstructure layer 2 has a partially light-transmitting grating area 2a, and the first grooves 21 of the grating area 2a form a shielding area due to the presence of the pigments of the first filling layer 22, and the areas between adjacent first grooves 21 are light-transmitting areas; the pigments can be selected from a variety of colors, and in this embodiment, the example of orange pigment and aluminum as the enhanced reflective material is used for illustration. The outer side surface of the second microstructure layer 3 forms second grooves 31, and the shape and spacing of the second grooves 31 are not limited, and can be determined according to the requirements of the image of the micro-graphic structure 33. The micro-graphic structure 33 forms an image area due to the presence of the enhanced reflective material of the second filling layer 32 in the second grooves 31, and the area between adjacent second grooves 31 is a light leakage area.

[0093] The observer observes from top to bottom from one side of the first microstructure layer 2, that is, observes from the side filled with pigment, and the light first reaches the first microstructure layer 2, wherein part of the light reaching the blocked part of the grating structure 23 is directly reflected to reach the observer, and the light reaching the light-transmitting part of the grating structure 23 passes through the substrate 1 to reach the second microstructure layer 3. Part of the light reaching the second microstructure layer 3 passes through the light leakage part of the micro-graphic structure 33, and the other part is reflected back to the grating area 2a of the first microstructure layer 2 at the second filling layer 32, so that the observer can receive the image of the micro-graphic structure 33, and the reflected light of the first microstructure layer 2 and the reflected light of the second microstructure layer 3 together form a color gradient pattern A. At the same time, on the other hand, the high reflectivity of the reflective material to light is enhanced, which has the effect of enhancing the brightness of the color image of the grating structure 23, achieving a strong pattern contrast effect, and the color gradient pattern A is clear and obvious. In this embodiment, the color gradient pattern A presents a gradient from orange to white. In addition, as the optical anti-counterfeiting document is tilted at different angles, the relative position / angle of the reflected light of the first microstructure layer 2 and the reflected light of the second microstructure layer 3 changes, which is equivalent to forming a dynamic change effect, so that the color gradient pattern A of the micro-image area 3a also presents a dynamic change effect.

[0094] The optical anti-counterfeiting document forms a clear and bright color gradient pattern A with moiré magnification through the cooperation of the grating structure 23 and the micro-graphic structure 33, which presents a dynamic changing effect at different angles to achieve an anti-counterfeiting effect; since there is no focusing lens structure, there is no concept of "focal length" and "focus", so there is no need to strictly control parameters such as lens morphology and thickness of substrate 1, which reduces the difficulty of making anti-counterfeiting documents. The grooved grating structure 23 also reduces the risk of contamination to a certain extent, ensuring high-quality optical imaging and visual effects.

[0095] On the basis of the above scheme, the optical anti-counterfeiting document further includes: a characteristic microstructure 34, formed on the surface of the second microstructure layer 3 facing away from the substrate 1, and a third filling layer 35 is also arranged on the characteristic microstructure 34. The material of the third filling layer 35 can be the same as that of the first filling layer 22, or the same as that of the second filling layer 32. In this embodiment, the material of the third filling layer 35 is the same as that of the second filling layer 32, and aluminum is selected as the enhanced reflection material. The characteristic microstructure 34 and the micro-graphic structure 33 are arranged in different areas of the second microstructure layer 3, that is, the second microstructure layer 3 includes a micro-graphic area 3a and an integrated area 3b.

[0096] It is worth noting that the characteristic microstructure 34 of the integrated area 3b presents its own inherent properties and does not interact with the grating structure 23 of the first microstructure layer 2. However, the optical characteristics presented by the characteristic microstructure 34 of the integrated area 3b can be non-moiré-acted by the pigment in the first groove 21 of the grating structure 23 in the corresponding grating area 2a above, presenting the overall effect of the integration of the above-mentioned first filling layer 22 pigment and the properties of the integrated area 3b, thereby presenting a characteristic pattern different from the color gradient pattern A of the micro-graphic area 3a.

[0097] The characteristic microstructure 34 of the integrated area 3b can be set in a variety of ways, such as a holographic grating, a Fresnel relief grating, a sub-wavelength microstructure unit, a reflective blazed grating, a flat surface, a printed pattern, an ink coating, a fluorescent material coating, a magnetic material coating, a phosphorus material coating or a selective absorption micro-nano structure. Figure 1 and Figure 6 As shown, the integrated region 3b is provided with two characteristic microstructures 34: a blazed grating 341 and a holographic grating 342, which form a Figures 2 to 4 The embossed hemispherical pattern B and digital pattern C shown in the figure are characterized by a hemispherical shape protruding from the plane where the optical anti-counterfeiting element is located, with a metallic luster, and only showing grayscale changes of light and dark. The color of the pigment of the superimposed first filling layer 22 shows an overall orange grayscale change. The digital pattern C "0" presents a holographic rainbow color gradient pattern, which is superimposed with the pigment of the first filling layer 22, and comprehensively forms a rainbow gradient color based on the pigment of the first filling layer 22, that is, the gradient color is orange as a whole. In the process of the optical anti-counterfeiting element changing from 30° to the left to 30° to the right, in addition to the stripes of the color gradient pattern A changing with the change of the tilt angle, moving to the right in turn, showing the dynamic characteristics of changing with the change of the tilt angle, the embossed hemispherical pattern B also changes during the tilting process, and the bright spot in the hemisphere also moves from left to right, and the rainbow color of the digital pattern C also changes accordingly.

[0098] Specifically, a metal aluminum layer is provided on the blazed grating 341 as an enhanced reflection material. The blazed grating 341 has different inclination angles, and can form an embossed hemisphere with a metallic texture. In this embodiment, the blazed grating 341 has a width of 5 μm and a depth of 0.5 μm. The holographic grating 342 forms a digital pattern C, and the period of the holographic grating 342 is 2 μm and the depth is 0.3 μm. Figure 1 In the x-direction (not directly shown in the figure, with the y-direction and the z-direction as reference), the above-mentioned micro-image structure 33, grating structure 23, blazed grating 341 and holographic grating 342 all maintain the same parameters, that is, have the same extension length in the x-direction.

[0099] The enhanced reflection material can be one or more of a single dielectric layer, a multi-layer dielectric layer, a metal reflection structure, and a metal / dielectric stack. For example, the common metal aluminum selected in this embodiment can be used as an enhanced reflection material by quickly obtaining an aluminum coating with a high reflectivity through thermal evaporation. For example, titanium dioxide is also a commonly used high refractive index dielectric material with a high reflectivity; high refractive index / low refractive index material stacks can also produce high reflectivity, such as "titanium dioxide / magnesium fluoride" stacks; "Fabry-Perot" resonant cavity is a more efficient stack structure that can obtain high reflectivity while forming a specific color. Its general structure is "metal reflective layer / dielectric layer / metal absorption layer" or its mirror structure, such as "metal silver reflective layer / cryolite dielectric layer / metal nickel absorption layer", where the metal can be aluminum, gold, silver, chromium, iron and other materials, and of course alloys can also be used; the medium can be magnesium fluoride (MgF2), lithium fluoride (LiF), silicon oxide (SiO2), aluminum oxide (Al2O3), titanium oxide (TiO2), zinc sulfide (ZnS), silicon nitride (Si3N4) and other materials. Of course, metal and dielectric materials are not limited to the above materials, and other metals and dielectrics can also be selected.

[0100] It should be known that the larger the thickness of the optical anti-counterfeiting document and the smaller the size of the imaged grating structure 23 and the micro-graphic structure 33, the faster the speed of the dynamic feature and the easier it is to identify. However, since the optical anti-counterfeiting element, such as the security thread, needs to maintain a small thickness, the size of the grating structure 23 and the micro-graphic structure 33 must be reduced to ensure that the dynamic feature is easy for the public to identify. This also increases the difficulty of making anti-counterfeiting documents to a certain extent, and the difficulty of counterfeiting becomes greater, that is, the anti-counterfeiting effect is better.

[0101] In one embodiment, the thickness of the substrate 1 is set to H1; Figure 1As shown in the arrangement direction of the grating structure 23, from the cross-section, the width of the area between two adjacent first grooves 21 and the width of the first groove 21 on either side form the characteristic size L1 of the grating structure 23, and the characteristic size range of the grating structure 23 is: 0.1μm~H1; in the micro-graphic structure 33, the width of the area between two adjacent second grooves 31 and the width of the second groove 31 on either side form the characteristic width L2 of the micro-graphic structure 33, and the characteristic width range of the micro-graphic structure 33 is: 0.1μm~H1. Under this size limit, the grating structure 23 and the micro-graphic structure 33 can produce high-quality dynamic features, which are easy to be observed.

[0102] Furthermore, when the optical anti-counterfeiting document is applied to the security line, that is, when it is manufactured in the banknote in the form of a windowed security line during the papermaking process, the thickness of the security line is a very important parameter, and its thickness determines the flatness of the paper and the continuity of subsequent printing. Therefore, the thickness range of the substrate 1 is set to: H1≤50μm, which can present the preset dynamic characteristics and can be easily identified by the public. When the thickness of the security line exceeds 50μm, the security line will have an adverse effect on the flatness of the paper, and the paper will have obvious undulations and wrinkles near the windowed security line. Such wrinkles and undulations will have an adverse effect on subsequent printing, causing problems in the transfer of paper, the image quality of the printed product, and ink adhesion. Compared with the conventional microlens structure, the grating structure 23 set in this embodiment is more suitable for security line documents, has low thickness requirements, and can ensure a good moiré magnification effect.

[0103] In one embodiment, the total area of ​​the first grooves 21 accounts for 10% to 90% of the total area of ​​the grating structure 23; the total area of ​​the second grooves 31 accounts for 10% to 90% of the total area of ​​the micro-graphic structure 33. Preferably, the total area of ​​the first grooves 21 accounts for 40% to 60% of the total area of ​​the grating structure 23; the total area of ​​the second grooves 31 accounts for 40% to 60% of the total area of ​​the micro-graphic structure 33. This is because the observer finally observes the grating structure 23 of the first microstructure layer 2 and the micro-graphic structure 33 of the second microstructure layer 3, so the area ratio of the two should be close to 50% to ensure the formation of two color gradients with similar color intensities.

[0104] In one embodiment, the bottom of the second groove 31 of the micro-graphic structure 33 of the optical anti-counterfeiting element is flat, and the second groove 31 with such a flat bottom surface will not converge the incident light. In order to more efficiently utilize incident light from different directions and illuminate other positions more efficiently, a preferred solution is to set the bottom of the second groove 31 of the micro-graphic structure 33 to be flat, that is, the surface of the second groove 31 close to the substrate 1 has certain random undulations to form a diffuse reflection surface. Such random undulations only play a role in diffuse scattering of light, and do not change the overall flatness of the second groove 31 of the micro-graphic structure 33.

[0105] Since the grooves of the grating structure 23 are filled with pigments, they usually have a diffuse reflection effect. Therefore, the morphology of the first groove 21 of the grating structure 23 does not need to be strictly limited. Even if the first groove 21 has a special morphology, such as a holographic grating 342, etc., since general pigments contain liquid, for example, red ink is red pigment + solvent, the refractive index of the solvent is generally very close to the refractive index of the microstructure forming layer, so the solvent will optically "smooth" the microstructure.

[0106] The above-mentioned grating structure 23 can be set to different types, such as a periodic array and / or a non-periodic array and / or a random array and / or a local periodic array composed of multiple grating units. In this embodiment, the grating structure 23 is preferably periodic, and the sampling and magnification effect is good. In contrast, the micro-graphic structure 33 reflects the pattern and dynamic features that are ultimately desired to be produced after moiré sampling and magnification. The main information is generally carried by the micro-graphic structure 33. Therefore, the micro-graphic is generally in various forms, which can be non-periodic, periodic, or short-range periodic and long-range non-periodic.

[0107] The characteristic size of the grating reflects the size of the grating structure 23. When the grating structure 23 changes periodically, the characteristic size is defined as the length of the repeated change of the grating structure 23; when the grating structure 23 is non-periodic, the characteristic size is the length from one edge of the grating structure 23 to the corresponding edge of the next grating structure 23.

[0108] The characteristic size of the grating structure 23 generally remains unchanged, and the characteristic size of the micro-graphic structure 33 changes to a certain extent according to a preset effect.

[0109] Therefore, if Figures 2 to 4 As shown, the periodic grating structure 23 and the non-completely periodic micro-graphic structure 33 are coordinated. When the above-mentioned optical anti-counterfeiting element changes from tilting 30° to the left to tilting 30° to the right, the color gradient stripes of the pattern also change with the change of the tilt angle, and move to the right in turn, presenting a dynamic feature that changes with the change of the tilt angle.

[0110] Furthermore, the optical anti-counterfeiting document further includes a protective layer 4, which is disposed on the surface of the first microstructure layer 2 and / or the second microstructure layer 3 on the side away from the substrate 1, and the protective layer 4 is a transparent coating or a translucent coating. In this embodiment, the grating area 2a is covered with hot melt adhesive as the protective layer 4, and its main material is an acrylic resin material, which can melt at a certain temperature and bond with paper, plastic, etc., to play a protective role, while solving the problems of bonding firmness and circulation resistance. The hot melt adhesive is a transparent material to avoid affecting the performance of the optical anti-counterfeiting feature.

[0111] In one embodiment, an isolation reflective layer 5 is disposed on the surface of the first microstructure layer 2 or the second microstructure layer 3 on the side facing away from the substrate 1, and the side opposite to the isolation reflective layer 5 is the observation side. In this embodiment, the isolation reflective layer 5 is covered on the outside of the micro-graphic structure 33. In this embodiment, the isolation reflective layer 5 can be black ink to achieve efficient reflection of light, solve the light leakage problem of the second microstructure layer 3, improve the color contrast of the optical anti-counterfeiting element, and achieve better recognition.

[0112] In one embodiment, a magnetic coding structure 6 is disposed on the surface of the isolation reflective layer 5 facing away from the substrate 1. That is, the magnetic coding structure 6 is printed outside the isolation reflective layer 5. Due to the existence of the isolation reflective layer 5, the observer is separated from the magnetic coding structure 6, and the observer will not see the magnetic coding structure 6 from the side of the grating structure 23, that is, the magnetic coding structure 6 will not affect the appearance of the optical anti-counterfeiting element, and the combination of magnetic machine-readable features and dynamic features is achieved.

[0113] In addition, a protective layer 4 may also be provided on the surface of the side where the magnetic coding structure 6 is located to achieve a protective effect.

[0114] This embodiment also provides a method for preparing an optical anti-counterfeiting document, comprising the following steps:

[0115] S1, providing a substrate 1, wherein the substrate 1 has a first surface 11 and a second surface 12 opposite to each other.

[0116] The substrate 1 is a transparent structure, and the thickness is determined according to the requirements of the anti-counterfeiting document.

[0117] S2 , forming a first microstructure layer 2 on the first surface 11 of the substrate 1 .

[0118] The first microstructure layer 2 is made of a transparent material, and covers the upper surface of the substrate 1 .

[0119] S3 , forming a plurality of spaced first grooves 21 on a surface of the first microstructure layer 2 facing away from the substrate 1 .

[0120] The first groove 21 is formed by micro-nano processing methods such as photolithography, electron beam etching or laser etching, and the depth of the first groove 21 is 1 μm-2 μm.

[0121] S4 , disposing a first filling layer 22 in the first groove 21 to form a grating structure 23 .

[0122] The material of the first filling layer 22 of this embodiment is orange pigment, and other pigments can also be selected. The method of filling the pigment is to scrape the liquid pigment into the first groove 21. The liquid has leveling properties. When the amount of water is sufficient, the first groove 21 is filled.

[0123] S5 , forming a second microstructure layer 3 on the second surface 12 of the substrate 1 .

[0124] Similarly, the second microstructure layer 3 is also made of a transparent material, and the second microstructure layer 3 covers the lower surface of the substrate 1 .

[0125] S6 , forming a second groove 31 on the surface of the second microstructure layer 3 facing away from the substrate 1 .

[0126] Similarly, the second groove 31 is formed by micro-nano processing methods such as photolithography, electron beam etching or laser etching, and the depth of the second groove 31 is 1 μm-2 μm.

[0127] S7 , disposing a second filling layer 32 in the second groove 31 to form a micro-image structure 33 .

[0128] In this embodiment, the material of the second filling layer 32 is an enhanced reflection material, such as metal aluminum. The enhanced reflection material can be filled by vapor deposition, scraping or micro-printing, and the thickness is set to 20nm-50nm.

[0129] The specific vapor deposition method is: by vapor deposition, the enhanced reflective material is deposited on the surface of the entire second microstructure layer 3 facing away from the substrate 1, and then the enhanced reflective material outside the second groove 31 is removed by a specific hollowing method, and only the enhanced reflective material inside the second groove 31 is retained. The vapor deposition method includes physical vapor deposition and chemical vapor deposition, such as thermal evaporation, magnetron sputtering, electron beam evaporation, ion beam evaporation, reactive chemical vapor deposition, etc. When the vapor deposition method is adopted, the enhanced reflective material can be one or more of a single-layer dielectric layer, a multi-layer dielectric layer, a metal reflective structure, and a metal / dielectric laminate. For example, the common metal aluminum selected in this embodiment can be quickly obtained by thermal evaporation. The aluminum coating with a higher reflectivity is used as the enhanced reflective material. Alternatively, titanium dioxide is also a commonly used high refractive index dielectric material with a high reflectivity; high refractive index / low refractive index material stacks can also produce high reflectivity, such as "titanium dioxide / magnesium fluoride" stacks; the "Fabry-Perot" resonant cavity is a more efficient stacked structure that can achieve high reflectivity while forming a specific color. Its general structure is "metal reflection layer / dielectric layer / metal absorption layer" or its mirror structure, such as "metal silver reflection layer / cryolite dielectric layer / metal nickel absorption layer", where the metal can be aluminum, gold, silver, chromium, iron and other materials, and of course alloys can also be used; the medium can be magnesium fluoride (MgF2), lithium fluoride (LiF), silicon oxide (SiO2), aluminum oxide (Al2O3), titanium oxide (TiO2), zinc sulfide (ZnS), silicon nitride (Si3N4) and other materials.

[0130] The specific scraping method is: by scraping, the fluid containing the enhanced reflection material is coated on the surface of the second microstructure layer 3 on the side away from the substrate 1, and the fluid outside the second groove 31 is "driven" into the second groove 31 by external force, such as a scraper, extrusion, etc. during coating. If necessary, the outside of the second groove 31 can be cleaned again to remove the residual fluid outside the second groove 31, so as to achieve the purpose of having only the enhanced reflection material inside the second groove 31. The material used for reflection enhancement by scraping is a high-reflectivity pigment, ink, etc. formed by crushing the above-mentioned coating structure. The pigment obtained after crushing the above-mentioned vapor deposition or the further prepared ink not only has fluidity, but also has a high reflectivity effect equivalent to the reflectivity of the coating. The most commonly used ones are metal aluminum ink, pearlescent ink, liquid crystal and optically variable ink, etc.

[0131] The micro-printing method is specifically as follows: a raised enhanced reflective material is obtained by micro-printing, similar to the gravure printing process, another preset gravure is filled with the enhanced reflective material, and the material at other positions of the gravure plane is scraped clean, and then the gravure filled with the enhanced reflective material is pressed against the substrate 1, and the material in the gravure is transferred to the substrate 1, thereby obtaining the desired structure. It should be known that this method forms a raised second filling layer 32.

[0132] It can be known that steps S2-S4 and steps S5-S7 can be swapped.

[0133] In one embodiment, the method for preparing an optical anti-counterfeiting document further comprises the following steps:

[0134] S8, forming an isolation reflection layer 5 on the surface of the second microstructure layer 3 facing away from the substrate 1.

[0135] Since the groove area of ​​the grating structure 23 and the micro-graphic structure 33 occupies 10%-90% of the entire structure area, and is not completely filled, part of the light will always be observed by the observer from the second microstructure layer 3, interfering with the overall optical effect. Therefore, an isolation reflective layer 5 with high reflection or color absorption is coated on the outside of the second microstructure layer 3 to achieve better color contrast, improve observability, and play a role in color absorption and covering.

[0136] S9, a magnetic encoding structure 6 is provided on the surface of the isolation reflective layer 5 which is away from the substrate 1.

[0137] Due to the existence of the isolation reflective layer 5, the observer is separated from the magnetic coding structure 6, and the observer will not be able to see the magnetic coding structure 6 from the side of the grating structure 23. The magnetic machine-readable coding structure is integrated into the optical anti-counterfeiting element to improve the anti-counterfeiting performance.

[0138] S10 , forming a protective layer 4 on the surface of the second microstructure layer 3 and the first microstructure layer 2 facing away from the substrate 1 .

[0139] Due to the needs of process and subsequent circulation resistance, it is necessary to apply one or more layers of coating on the upper and lower surfaces of optical anti-counterfeiting documents such as security lines. These coatings can play a bonding role with paper, plastic and other carriers, forming a protective layer 4 on the surface of the optical anti-counterfeiting document to ensure that it will not be damaged by external physical, chemical and other factors during the subsequent circulation process, and avoid the disappearance of the moiré magnification effect during the circulation process, resulting in the disappearance of the preset pattern and dynamic effect, affecting the public anti-counterfeiting effect of the security line. In the optical anti-counterfeiting element of this embodiment, since the observer observes from the side of the first microstructure layer 2, the grating structure 23 of the first microstructure layer 2 is covered with a protective layer 4, which plays a protective or bonding role, and the protective layer 4 is transparent or translucent; the covering method can be a variety of methods such as coating, printing, and spraying.

[0140] In addition, similar to the first microstructure layer 2, the outermost side of the second microstructure is also covered with a protective layer 4 to play a protective or bonding role.

[0141] Example 2

[0142] like Figures 7 to 12 As shown, this embodiment provides an optical anti-counterfeiting document, including a substrate 1, a first microstructure layer 2 and a second microstructure layer 3. The substrate 1 has a first surface 11 and a second surface 12 opposite to each other. Figure 7 In this embodiment, the first surface 11 is the lower surface, and the second surface 12 is the upper surface; the first microstructure layer 2 is arranged on the first surface 11, and a plurality of first grooves 21 are formed on the surface of the first microstructure layer 2 on the side away from the substrate 1, and a first filling layer 22 is arranged in the first groove 21 to form a grating structure 23, and the material of the first filling layer 22 is an enhanced reflection material; the second microstructure layer 3 is arranged on the second surface 12, and a second groove 31 is formed on the surface of the second microstructure layer 3 on the side away from the substrate 1, and a second filling layer 32 is arranged in the second groove 31 to form a micro-graphic structure 33, and the material of the second filling layer 32 is a pigment; the grating structure 23 and the micro-graphic structure 33 are arranged correspondingly relative to the substrate 1 to cooperate to form a pattern with color gradient. One side of the second filling layer 32 is the observation side, that is, the observer observes from the second filling layer 32 side from top to bottom.

[0143] like Figure 7 and Fig.12 As shown, the difference between this embodiment and embodiment 1 is that the first groove 21 of the grating structure 23 is filled with an enhanced reflection material, the second groove 31 of the micro-graphic structure 33 is filled with a pigment with a certain color, and the characteristic microstructure 34 of the second microstructure layer 3 is also filled with a pigment, wherein the blazed grating 341 covers aluminum pigment, presenting a metallic luster, and the holographic grating 342 covers a pigment with a certain color. The surface of the first groove 21 close to the substrate 1 has certain random undulations, forming a diffuse reflection surface. The isolation reflection layer 5 and the magnetic encoding structure 6 are arranged on the outside of the first microstructure layer 2.

[0144] The observer still observes from the side where the pigment is located. The observer observes from top to bottom from the side of the second microstructure layer 3. The light first reaches the second microstructure layer 3, among which part of the light reaching the image part of the micro-graphic structure 33 is directly reflected to reach the observer, and the light reaching the light leakage part of the micro-graphic structure 33 passes through the substrate 1 to reach the first microstructure layer 2. Part of the light reaching the first microstructure layer 2 passes through the light-transmitting part of the grating structure 23, and the other part is reflected at the first filling layer 22 and returned to the micro-graphic area 3a of the second microstructure layer 3. On the one hand, the observer receives the image of the micro-graphic structure 33, and the reflected light of the second microstructure layer 3 and the reflected light of the first microstructure layer 2 together form a color gradient pattern A. At the same time, on the other hand, the high reflectivity of the reflective material to light is enhanced, which has an effect of enhancing the brightness of the color image of the micro-graphic structure 33, achieving a strong pattern contrast effect, and the color gradient pattern A is clear and obvious. In this embodiment, similarly, the color gradient pattern A presents a gradient from orange to white. In addition, as the optical anti-counterfeiting document is tilted at different angles, the relative position / angle of the reflected light of the second microstructure layer 3 and the reflected light of the first microstructure layer 2 changes, which is equivalent to forming a dynamic change effect, and the color gradient pattern A of the micro-image area 3a also presents a dynamic change effect.

[0145] The optical anti-counterfeiting document forms a clear and bright color gradient pattern A with moiré magnification through the cooperation of the grating structure 23 and the micro-graphic structure 33, which presents a dynamic changing effect at different angles to achieve an anti-counterfeiting effect; since there is no focusing lens structure, there is no concept of "focal length" and "focus", so there is no need to strictly control parameters such as lens morphology and thickness of substrate 1, which reduces the difficulty of making anti-counterfeiting documents. The grooved grating structure 23 also reduces the risk of contamination to a certain extent, ensuring high-quality optical imaging and visual effects.

[0146] The parts of this embodiment that are the same as those of Embodiment 1 are not described in detail here.

[0147] Example 3

[0148] like Figures 13 to 22 As shown, this embodiment provides an optical anti-counterfeiting document, including a substrate 1, a first microstructure layer 2 and a second microstructure layer 3. The substrate 1 has a first surface 11 and a second surface 12 opposite to each other. Fig.13In this embodiment, the first surface 11 is the upper surface, and the second surface 12 is the lower surface; the first microstructure layer 2 is arranged on the first surface 11, and a plurality of spaced first grooves 21 are formed on the surface of the first microstructure layer 2 on the side away from the substrate 1, and a first filling layer 22 is arranged in the first groove 21 to form a grating structure 23, and the material of the first filling layer 22 is a pigment; the second microstructure layer 3 is arranged on the second surface 12, and a second groove 31 is formed on the surface of the second microstructure layer 3 on the side away from the substrate 1, and a second filling layer 32 is arranged in the second groove 31 to form a micro-graphic structure 33, and the material of the second filling layer 32 is a pigment; the grating structure 23 and the micro-graphic structure 33 are arranged correspondingly relative to the substrate 1 to cooperate to form a pattern with color gradient. One side of the first filling layer 22 or one side of the second filling layer 32 can be used as the observation side, that is, the observer can observe from the first filling layer 22 side from top to bottom, or from the second filling layer 32 side from bottom to top.

[0149] Taking the example of an observer observing from top to bottom from the side where the grating structure 23 is located, the light first reaches the first microstructure layer 2, wherein part of the light reaching the shielded part of the grating structure 23 is directly reflected to reach the observer, and the light reaching the light-transmitting part of the grating structure 23 passes through the substrate 1 to reach the second microstructure layer 3. Part of the light reaching the second microstructure layer 3 passes through the light leakage part of the micro-graphic structure 33, and the other part is reflected back to the grating area 2a of the first microstructure layer 2 under the shielding of the second filling layer 32, so that the observer receives the image of the micro-graphic structure 33, and the reflected light of the first microstructure layer 2 and the reflected light of the second microstructure layer 3 together form a color gradient pattern A. In this embodiment, the color gradient pattern A presents a gradient from orange to white. In addition, as the optical anti-counterfeiting document is tilted at different angles, the relative position / angle of the reflected light of the first microstructure layer 2 and the reflected light of the second microstructure layer 3 changes, which is equivalent to forming a dynamic change effect, and the color gradient pattern A of the micro-graphic area 3a also presents a dynamic change effect.

[0150] The optical anti-counterfeiting document forms a clear and bright moiré color gradient pattern A through the cooperation of the grating structure 23 and the micro-graphic structure 33, which presents a dynamic changing effect at different angles to achieve an anti-counterfeiting effect; since there is no focusing lens structure, there is no concept of "focal length" and "focus", so there is no need to strictly control parameters such as lens morphology and thickness of substrate 1, which reduces the difficulty of making anti-counterfeiting documents. The grooved grating structure 23 also reduces the risk of contamination to a certain extent, ensuring high-quality optical imaging and visual effects.

[0151] like Figures 13 to 22As shown, the difference between this embodiment and embodiment 1 is that the second groove 31 on the second microstructure layer 3 under the substrate 1 is filled with a pigment with a certain color, and the characteristic microstructure 34 of the second microstructure layer 3 is also filled with the pigment, wherein the characteristic microstructure 34 is a groove structure, and the formed digital pattern C is 2.

[0152] like Figures 14 to 17 As shown, when the optical anti-counterfeiting element changes from tilting 30° to the left to tilting 30° to the right, the stripes of the color gradient pattern A change with the change of the tilt angle, and move to the right in sequence, showing a dynamic feature that changes with the change of the tilt angle. The orange number "2" presented in the numerical pattern is the front side, and the position remains unchanged.

[0153] like Figures 18 to 21 As shown, when observing from the side of the second microstructure layer 3, when the optical anti-counterfeiting element changes from tilting 30° to the left to tilting 30° to the right, the stripes of the color gradient pattern A change with the change of the tilt angle, and move to the left in sequence, showing a dynamic feature that changes with the change of the tilt angle. The orange number "2" presented in the numerical pattern is the reverse side, and the position remains unchanged. It can be seen that when the observation direction is opposite, the dynamic direction is opposite.

[0154] In addition, the material of the isolation reflection layer 5 is preferably a material with low absorption rate for the visible light spectrum and high reflection for the entire visible light spectrum, more preferably a white pigment, such as white paint composed of TiO2 particles.

[0155] The parts of this embodiment that are the same as those of Embodiment 1 are not described in detail here.

[0156] Example 4

[0157] like Figure 23 to Figure 28 As shown, this embodiment provides an optical anti-counterfeiting document, including a substrate 1, a first microstructure layer 2 and a second microstructure layer 3. The substrate 1 has a first surface 11 and a second surface 12 opposite to each other. Fig.23In this embodiment, the first surface 11 is the lower surface, and the second surface 12 is the upper surface; the first microstructure layer 2 is arranged on the first surface 11, and a plurality of spaced first grooves 21 are formed on the surface of the first microstructure layer 2 on the side away from the substrate 1, and a first filling layer 22 is arranged in the first groove 21 to form a grating structure 23, and the material of the first filling layer 22 is an enhanced reflection material; the second microstructure layer 3 is arranged on the second surface 12, and a second groove 31 is formed on the surface of the second microstructure layer 3 on the side away from the substrate 1, and a second filling layer 32 is arranged in the second groove 31 to form a micro-graphic structure 33, and the material of the second filling layer 32 is an enhanced reflection material; the grating structure 23 and the micro-graphic structure 33 are arranged correspondingly relative to the substrate 1 to cooperate to form a pattern with a gradient. One side of the first filling layer 22 or one side of the second filling layer 32 can be used as the observation side, that is, the observer can observe from the first filling layer 22 side from top to bottom, or from the second filling layer 32 side from bottom to top.

[0158] like Fig.23 and Fig.28 As shown, the difference between this embodiment and embodiment 1 is that the first groove 21 of the grating structure 23 is filled with an enhanced reflection material. The isolation reflection layer 5 and the magnetic encoding structure 6 are arranged outside the first microstructure layer 2.

[0159] Taking the case where an observer observes from top to bottom from the side where the second filling layer 32 is located as an example, the observer observes from top to bottom from the side of the second microstructure layer 3, and the light first reaches the second microstructure layer 3, among which part of the light reaching the image part of the micro-graphic structure 33 is directly reflected to reach the observer, and the light reaching the light leakage part of the micro-graphic structure 33 passes through the substrate 1 to reach the first microstructure layer 2. Part of the light reaching the first microstructure layer 2 passes through the light-transmitting part of the grating structure 23, and the other part is reflected back to the micro-graphic area 3a of the second microstructure layer 3 under the shielding of the first filling layer 22, so that the observer can receive the image of the micro-graphic structure 33, and the reflected light of the second microstructure layer 3 and the reflected light of the first microstructure layer 2 together form a color gradient pattern A. At the same time, on the other hand, the high reflectivity of the reflective material to light is enhanced, which has the effect of enhancing the brightness of the image of the micro-graphic structure 33, achieving a strong pattern contrast effect, and the color gradient pattern A is clear and obvious. In this embodiment, the color gradient pattern A presents a gradient from silvery white to transparent, such as Figure 24 to Figure 27 As shown, the pattern brightness is high but the contrast is not high. In addition, as the optical anti-counterfeiting document is tilted at different angles, the relative position / angle of the reflected light of the first microstructure layer 2 and the reflected light of the second microstructure layer 3 changes, which is equivalent to forming a dynamic change effect. The color gradient pattern A of the micro-graphic area 3a also presents a dynamic change effect. The embossed hemispherical pattern B still has a metallic luster, and the digital pattern C still has a rainbow holographic feature.

[0160] The optical anti-counterfeiting document forms a clear and bright color gradient pattern A with moiré magnification through the cooperation of the grating structure 23 and the micro-graphic structure 33, which presents a dynamic changing effect at different angles to achieve an anti-counterfeiting effect; since there is no focusing lens structure, there is no concept of "focal length" and "focus", so there is no need to strictly control parameters such as lens morphology and thickness of substrate 1, which reduces the difficulty of making anti-counterfeiting documents. The grooved grating structure 23 also reduces the risk of contamination to a certain extent, ensuring high-quality optical imaging and visual effects.

[0161] In addition, the isolation reflective layer 5 is configured as a pigment coating having a certain color, which can achieve a color gradient effect that is easier to identify, such as in Fig.23 Based on the structure shown, Fig.28 As shown, an orange isolation reflective layer 5 is covered on the outer side of the first microstructure layer 2, and the color gradient pattern A of the obtained optical anti-counterfeiting document can present a gradient effect from orange to white.

[0162] The parts of this embodiment that are the same as those of Embodiment 1 are not described in detail here.

[0163] In the above description, the technical details of the patterning and etching of each layer are not described in detail. However, those skilled in the art should understand that various technical means can be used to form layers, regions, etc. of desired shapes. In addition, in order to form the same structure, those skilled in the art can also design methods that are not completely the same as the methods described above. In addition, although the various embodiments are described above separately, this does not mean that the measures in the various embodiments cannot be used in combination to advantage.

[0164] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. An optical anti-counterfeiting document, characterized in that: include: a substrate having opposing first and second surfaces; A first microstructure layer is disposed on the first surface; A plurality of spaced first grooves are formed on the surface of the first microstructure layer on the side facing away from the substrate, and a first filling layer is arranged in the first groove to form a grating structure; the first filling layer is a pigment or a reflection enhancing material; A second microstructure layer is disposed on the second surface; a second groove is formed on a surface of the second microstructure layer on a side away from the substrate, and a second filling layer is disposed in the second groove to form a micro-graphic structure; The second filling layer is a pigment or a reflective enhancement material; The grating structure and the micro-image structure are arranged correspondingly to the substrate to cooperate to form a gradient pattern.

2. The optical anti-counterfeiting document according to claim 1, characterized in that: The material of the first filling layer is a pigment, the material of the second filling layer is an enhanced reflection material, and one side of the first filling layer is an observation side.

3. The optical anti-counterfeiting document according to claim 1, characterized in that: The material of the first filling layer is a reflection enhancing material, the material of the second filling layer is a pigment, and one side of the second filling layer is an observation side.

4. The optical anti-counterfeiting document according to claim 1, characterized in that: The material of the first filling layer and the material of the second filling layer are both pigments, and the side where the first filling layer is located or the side where the second filling layer is located is the observation side.

5. The optical anti-counterfeiting document according to claim 1, characterized in that: The material of the first filling layer and the material of the second filling layer are both enhanced reflection materials, and the side where the first filling layer is located or the side where the second filling layer is located is the observation side.

6. The optical anti-counterfeiting document according to any one of claims 1 to 5, characterized in that: A characteristic microstructure is also formed on the surface of the second microstructure layer on the side facing away from the substrate, and a third filling layer is also arranged on the characteristic microstructure, and the material of the third filling layer is at least partially the same as the material of the first filling layer or the material of the second filling layer; The characteristic microstructure includes one or more of a holographic grating, a Fresnel relief grating, a subwavelength microstructure unit, a reflective blazed grating, a flat surface, a printed pattern, an ink coating, a fluorescent material coating, a magnetic material coating, a phosphorus material coating or a selective absorption micro-nanostructure.

7. The optical anti-counterfeiting document according to claim 2, 3 or 5, characterized in that: The enhanced reflection material is one or more of a single dielectric layer, a multi-layer dielectric layer, a metal reflection structure, and a metal / dielectric stack.

8. The optical anti-counterfeiting document according to claim 1, characterized in that: The thickness of the substrate is H1; In the arrangement direction of the grating structure, the width of the area between two adjacent first grooves and the width of the first groove on either side thereof form a characteristic size L1 of the grating structure, and the characteristic size range of the grating structure is: 0.1 μm to H1; In the micro-graphic structure, the width of the area between two adjacent second grooves and the width of the second groove on either side thereof form a characteristic width L2 of the micro-graphic structure, and the characteristic width range of the micro-graphic structure is: 0.1 μm to H1.

9. The optical anti-counterfeiting document according to claim 8, characterized in that: The thickness range of the substrate is: H1≤50 μm.

10. The optical anti-counterfeiting document according to claim 9, characterized in that: The total area of ​​the first grooves accounts for 10% to 90% of the total area of ​​the grating structure; The total area of ​​the second grooves accounts for 10% to 90% of the total area of ​​the micro-graphic structure.

11. The optical anti-counterfeiting document according to claim 2, 3 or 5, characterized in that: The groove where the enhanced reflection material is located has a surface on one side close to the substrate that is a diffuse reflection surface.

12. The optical anti-counterfeiting document according to claim 1, characterized in that: The grating structure is a periodic array and / or a non-periodic array and / or a random array and / or a partially periodic array composed of a plurality of grating units.

13. The optical anti-counterfeiting document according to claim 1, characterized in that: Also includes: The protective layer is arranged on a surface of the first microstructure layer and / or the second microstructure layer which is away from the substrate, and the protective layer is a transparent coating or a semi-transparent coating.

14. The optical anti-counterfeiting document according to claim 1, characterized in that: Also includes: The isolation reflection layer is arranged on a surface of the first microstructure layer or the second microstructure layer which is away from the substrate, and the side opposite to the isolation reflection layer is an observation side.

15. The optical anti-counterfeiting document according to claim 14, characterized in that: Also includes: The magnetic encoding structure is arranged on a surface of the isolation reflective layer which is away from the substrate.

16. A method for preparing an optical anti-counterfeiting document, characterized in that: include: providing a substrate having a first surface and a second surface opposite to each other; forming a first microstructure layer on a first surface of the substrate; Forming a plurality of first grooves spaced apart from each other on a surface of the first microstructure layer facing away from the substrate; A first filling layer is arranged in the first groove to form a grating structure, wherein the first filling layer is a pigment or a reflection enhancing material; forming a second microstructure layer on the second surface of the substrate; Forming a second groove on a surface of the second microstructure layer facing away from the substrate; A second filling layer is arranged in the second groove to form a micro-image structure, and the second filling layer is a pigment or a reflection-enhancing material.

17. The method for preparing an optical anti-counterfeiting document according to claim 16, characterized in that: After the second filling layer is arranged in the second groove to form a micro-graphic structure, the method further includes: forming an isolation reflection layer on a surface of the first microstructure layer or the second microstructure layer facing away from the substrate; A magnetic encoding structure is provided on a surface of the isolation reflective layer on a side away from the substrate; A protective layer is formed on a surface of the second microstructure layer and / or the first microstructure layer facing away from the substrate.

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