Multi-channel liquid crystal anti-counterfeiting element and anti-counterfeiting product

Abstract

The invention provides a multi-channel liquid crystal anti-counterfeiting element and an anti-counterfeiting product. The anti-counterfeiting element comprises at least one liquid crystal layer and at least one anti-counterfeiting layer, wherein the liquid crystal layer comprises at least two liquid crystal domains; liquid crystal molecules in the liquid crystal domains are arranged in the same direction, and liquid crystal molecules in adjacent liquid crystal domains are arranged in different directions. According to the anti-counterfeiting element and the anti-counterfeiting product with the anti-counterfeiting element, different near-field images and far-field holographic images can be respectively observed under different light source conditions, so that the anti-counterfeiting effect can be improved.

Description

Technical Field

[0001] The present application relates to the field of optical anti-counterfeiting, and in particular, to a multi-channel liquid crystal anti-counterfeiting element and an anti-counterfeiting product. Background Art

[0002] The increasing popularity of color copiers and digital imaging systems has led to an increasing number of counterfeit items. In order to prevent counterfeiting and forgery, certificates, securities and commercial products are often equipped with anti-counterfeiting elements to verify their authenticity and prevent unauthorized copying.

[0003] Compared with traditional printed patterns, optical anti-counterfeiting elements based on diffraction gratings, multi-layer interference structures, micro-mirrors and micro-lens arrays are more visually impactful and attractive, and are more effective in preventing counterfeiting through copying and scanning, and occupy a major position in the field of public anti-counterfeiting.

[0004] With the market promotion of optical technology, optical anti-counterfeiting elements are increasingly threatened by counterfeit products. For example, the marketization of holographic technology has developed rapidly in recent years, and holographic optically variable products can be easily obtained; the production technology of optically variable pigments that change color with angles has gradually become popular, and its cost has become lower and lower. As the anti-counterfeiting effect of color-changing optically variable technology has been challenged. A single feature can no longer meet the needs of anti-counterfeiting. A significant trend in the development of optical anti-counterfeiting is the composite and integrated application of technology, and many new optical anti-counterfeiting elements have emerged. Summary of the invention

[0005] The present application aims to solve at least one of the technical problems existing in the related art.

[0006] To this end, a first aspect of the present application is to propose a multi-channel liquid crystal anti-counterfeiting element.

[0007] The second aspect of the present application is to provide an anti-counterfeiting product.

[0008] In view of this, according to the first aspect of the present application, a multi-channel liquid crystal anti-counterfeiting element is proposed, comprising at least one liquid crystal layer, the liquid crystal layer comprising at least two liquid crystal domains; the liquid crystal molecules in the liquid crystal domains are arranged in the same direction, and the liquid crystal molecules in adjacent liquid crystal domains are arranged in different directions.

[0009] In the above embodiment, by dividing the liquid crystal layer into multiple regions, the arrangement of liquid crystal molecules in multiple regions can be controlled separately, so that the arrangement direction of the liquid crystal molecules in each liquid crystal domain is the same, and the arrangement directions of the liquid crystal molecules in adjacent liquid crystal domains are different. This difference provides a basis for encoding anti-counterfeiting information, and the observer can verify the authenticity of the anti-counterfeiting information through specific detection means.

[0010] In some technical solutions, the liquid crystal molecules are optionally cross-linked with each other. This structure not only enhances the stability and durability of the liquid crystal layer, but also helps to more accurately control the arrangement direction and optical properties of the liquid crystal molecules.

[0011] In some technical solutions, optionally, the width of the liquid crystal domain in at least one direction is less than 20 um. As the width of the liquid crystal domain decreases, the precision requirements in the manufacturing process become higher and higher, and the processing difficulty becomes greater and greater, so that counterfeiting can be effectively prevented.

[0012] In some technical solutions, optionally, the shape of the liquid crystal domain is one or more of a triangle, a square, a rectangle, a circle, a polygon or an irregular shape.

[0013] In practical applications, the shapes of liquid crystal domains can be combined and arranged according to the needs of anti-counterfeiting information, which can increase the complexity and security of anti-counterfeiting and help improve the anti-counterfeiting effect.

[0014] In some technical solutions, optionally, the thickness of the liquid crystal layer satisfies a half-wave plate condition relative to the wavelength of the incident light, so that the incident light experiences a 180-degree phase delay, thereby enhancing the visibility or contrast of the anti-counterfeiting information.

[0015] In some technical solutions, optionally, an orientation layer is also included; the orientation layer is arranged on one side of the liquid crystal layer and covers at least a partial area of ​​the liquid crystal layer; the long axis direction of the orientation layer molecules in the orientation layer is parallel or perpendicular to the long axis direction of the liquid crystal molecules covered under the orientation layer.

[0016] In the above technical solution, an orientation layer is introduced to selectively orient in different directions, so that the liquid crystal molecules in multiple liquid crystal domains are oriented according to the orientation direction of the orientation layer to control the arrangement of the liquid crystal molecules, thereby ensuring that the liquid crystal layer can change its optical properties in a predetermined manner.

[0017] In some technical solutions, a reflective layer is optionally included; the reflective layer is disposed on one side of the liquid crystal layer and covers at least a partial area of ​​the liquid crystal layer. In practical applications, the reflective layer reflects the incident light passing through the liquid crystal layer; thus, when performing anti-counterfeiting inspection, it is only necessary to illuminate one side of the liquid crystal layer with linearly polarized light, and the incident light passes through the liquid crystal layer and is reflected back by the reflective layer, so that the observer can perform anti-counterfeiting inspection on the same side.

[0018] In some technical solutions, optionally, the thickness of the liquid crystal layer satisfies a quarter wave plate condition relative to the wavelength of the incident light. In this way, after the incident light is reflected by the reflective layer, it will be phase delayed by 90 degrees again, thereby completing a complete 180 degree phase delay.

[0019] In some technical solutions, the reflective layer is optionally any one or more of a metal reflective layer, a layered interference structure, and a cholesteric liquid crystal layer. The above reflective layer structures are used in combination to achieve more complex optical functions.

[0020] In the above technical solution, optionally, it also includes an orientation layer; the orientation layer is arranged on the other side of the liquid crystal layer away from the reflective layer, and at least covers a partial area of ​​the liquid crystal layer; the long axis direction of the orientation layer molecules in the orientation layer is parallel or perpendicular to the long axis direction of the liquid crystal molecules covered under the orientation layer.

[0021] According to the second aspect of the present application, the present application also proposes an anti-counterfeiting product, which has an article and an anti-counterfeiting element disclosed in any of the above technical solutions, wherein the anti-counterfeiting element is arranged on the article. Therefore, the anti-counterfeiting product has all the beneficial effects of the anti-counterfeiting element disclosed in any of the above technical solutions, which will not be repeated here.

[0022] For example, the article is made of paper or plastic. The anti-counterfeiting element can be used as a window security line, film, label, optical wide strip or transparent window, etc., and is set on various articles. For example, on high-security products and high-value-added products such as banknotes, certificates or credit cards.

[0023] Additional aspects and advantages of the present application will become apparent in the following description or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which: Figure 1 One of the structural schematic diagrams of the anti-counterfeiting element in the embodiment of the present application is shown; Figure 2 The second structural schematic diagram of the anti-counterfeiting element in the embodiment of the present application is shown; Figure 3 The third structural schematic diagram of the anti-counterfeiting element in the embodiment of the present application is shown; Figure 4 A fourth structural schematic diagram of the anti-counterfeiting element in an embodiment of the present application is shown; Figure 5 The fifth structural diagram of the anti-counterfeiting element in the embodiment of the present application is shown; Figure 6 The sixth structural diagram of the anti-counterfeiting element in the embodiment of the present application is shown; Figure 7 The seventh structural diagram of the anti-counterfeiting element in the embodiment of the present application is shown; Figure 8 A schematic diagram showing the principle of the anti-counterfeiting element in the embodiment of the present application performing anti-counterfeiting inspection when the light source is a mobile phone screen; Fig. 9 A schematic diagram showing the principle of anti-counterfeiting inspection of the anti-counterfeiting element in the embodiment of the present application when the light source is ordinary light; Fig.10 A schematic diagram showing the principle of anti-counterfeiting inspection performed by the anti-counterfeiting element in the embodiment of the present application when the light source is laser; Fig.11 A schematic diagram showing the principle of anti-counterfeiting inspection of the anti-counterfeiting element in the embodiment of the present application when the light source is a flashlight of an ordinary mobile phone; Fig.12 A schematic diagram showing the principle of anti-counterfeiting inspection using linearly polarized light when the anti-counterfeiting element in the embodiment of the present application has a reflective layer; Fig.13 Schematic diagram of the principle of using laser for anti-counterfeiting inspection when the anti-counterfeiting element in an embodiment of the present application has a reflective layer.

[0025] in, Figures 1 to 13 The corresponding relationship between the reference numerals and the component names is as follows: 10-anti-counterfeiting element; 100-liquid crystal layer; 110-liquid crystal domain; 111-liquid crystal molecule; 200-orientation layer; 300-reflection layer; 400-substrate; 500-first near-field image "A"; 600-second near-field image "B"; 700-far-field holographic image "C"; 20-linear polarizer; 30-mobile phone screen; 40-observer; 50-screen. DETAILED DESCRIPTION

[0026] In order to more clearly understand the above-mentioned purposes, features and advantages of the present application, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0027] In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present application is not limited to the specific embodiments disclosed below.

[0028] Combine the following Figures 1 to 13 , the multi-channel liquid crystal anti-counterfeiting element and anti-counterfeiting product provided in the embodiments of the present application are described in detail through specific embodiments and their application scenarios.

[0029] Reference Figures 1 to 7 In some embodiments of the present application, a multi-channel liquid crystal anti-counterfeiting element 10 is provided, comprising a liquid crystal layer 100 .

[0030] Specifically, refer to Figure 1 and Figure 2The liquid crystal layer 100 is divided into a plurality of continuous regions, and each region is defined as a liquid crystal domain 110; wherein the arrangement directions of the liquid crystal molecules 111 in the liquid crystal domain 110 are the same, and the arrangement directions of the liquid crystal molecules 111 in adjacent liquid crystal domains 110 are different.

[0031] In the above embodiment, by dividing the liquid crystal layer 100 into multiple regions, the arrangement of the liquid crystal molecules 111 in the multiple regions can be controlled separately, so that the arrangement direction of the liquid crystal molecules 111 in each liquid crystal domain 110 is the same, and the arrangement directions of the liquid crystal molecules 111 in adjacent liquid crystal domains 110 are different. This difference provides a basis for encoding anti-counterfeiting information, and the observer 40 can verify the authenticity of the anti-counterfeiting information through specific detection means.

[0032] In practical applications, for the purpose of this application, anti-counterfeiting information is information that can be visually discerned, such as one or more patterns, letters, numbers, characters, etc.

[0033] Reference Figure 8 and Fig. 9 When the incident light is linearly polarized light, the observer 40 can observe on the other side with the help of the linear polarizer 20 whose transmission direction is orthogonal to the polarization direction of the incident light. The observer 40 can see the first near-field image "A" 500 imaged on the surface of the anti-counterfeiting element 10; and rotating the anti-counterfeiting element 10 and / or the linear polarizer 20 at a certain angle will transform the first near-field image "A" 500 into the second near-field image "B" 600, thereby presenting different anti-counterfeiting information.

[0034] Reference Fig.10 and Fig.11 When the incident light is laser, a far-field holographic image "C" 700 can be projected on a screen 50 (which can be any surface, such as a wall, a desktop, a paper surface, etc.) at a certain distance. When the incident light source is a point light source (a mobile phone LED (Light Emitting Diode) flash), the observer can also directly observe the far-field holographic image "C" 700 at a certain distance.

[0035] It can be seen that when the light source is ordinary light, since the naked eye can only perceive the difference in light intensity and color, but cannot perceive the difference in the polarization state of light, when ordinary light passes through the anti-counterfeiting element 10 of the present application, the naked eye cannot perceive the anti-counterfeiting information hidden in the anti-counterfeiting element 10, that is, the anti-counterfeiting information is hidden; only when the anti-counterfeiting element 10 is placed between orthogonal linear polarizers 20, when ordinary light passes through the linear polarizer 20 and becomes linearly polarized light, and then passes through the liquid crystal layer 100, when the light passes through the area of ​​the adjacent liquid crystal domain 110, the polarization state changes, and thus, the observer can observe the anti-counterfeiting information with the help of the linear polarizer 20. Therefore, under ordinary light sources, the anti-counterfeiting information of the anti-counterfeiting product can only be observed with the help of the linear polarizer 20, which helps to improve the anti-counterfeiting effect. The anti-counterfeiting element 10 of the present application has a multi-level anti-counterfeiting effect under different light source conditions, which helps to improve the anti-counterfeiting performance.

[0036] In this embodiment, the linear polarized light can be polarized light generated after ordinary light passes through the linear polarizer 20, or it can be linear polarized light emitted by the mobile phone screen 30 (or linear polarized light such as computer screen light, mirror reflection light, etc.), and this embodiment is not limited to this.

[0037] The first near-field image "A" 500 and the second near-field image "B" 600 are different, that is, the second near-field image "B" 600 is deformed compared to the first near-field image "A" 500. Exemplarily, the deformation means that part or all of the area of ​​the first near-field image "A" is enlarged, reduced or distorted, or part or all of the area of ​​the first near-field image "A" 500 is displaced, rotated or flipped, or part or all of the area of ​​the first near-field image "A" 500 disappears, etc.

[0038] In the above embodiment, the liquid crystal molecules 111 are cross-linked to form a thin film, which not only enhances the stability and durability of the liquid crystal layer 100, but also helps to more accurately control the arrangement direction and optical properties of the liquid crystal molecules 111.

[0039] In some embodiments, the width of the liquid crystal domain 110 in at least one direction is less than 20 um. Preferably, less than 5 um. As the width of the liquid crystal domain 110 decreases, the precision requirements in the manufacturing process become higher and higher, and the processing difficulty becomes greater and greater, so that counterfeiting can be effectively prevented.

[0040] In some embodiments, the shape of the liquid crystal domain 110 is one or more of a triangle, a square, a rectangle, a circle, a polygon or an irregular shape. In practical applications, the shape of the liquid crystal domain 110 can be combined and arranged according to the needs of the anti-counterfeiting information. For example, liquid crystal domains 110 of different shapes can be used to construct complex patterns, letters, numbers or two-dimensional codes and other anti-counterfeiting marks. In this way, the complexity and security of anti-counterfeiting can be improved, thereby helping to improve the anti-counterfeiting effect.

[0041] In some embodiments, the thickness of the liquid crystal layer 100 satisfies a half-wave plate condition relative to the wavelength of the incident light, so that the incident light experiences a 180-degree phase delay, thereby enhancing the visibility or contrast of the anti-counterfeiting information.

[0042] Reference Figure 3 In some embodiments, the anti-counterfeiting element 10 further includes an orientation layer 200, which is disposed on one side of the liquid crystal layer 100 and covers at least a partial area of ​​the liquid crystal layer 100; the long axis direction of the orientation layer molecules in the orientation layer 200 is parallel or perpendicular to the long axis direction of the liquid crystal molecules 111 covered under the orientation layer 200.

[0043] In the above embodiment, an orientation layer 200 is introduced for selectively orienting in different directions, so that the liquid crystal molecules 111 in the plurality of liquid crystal domains 110 are oriented according to the orientation direction of the orientation layer 200 to control the arrangement of the liquid crystal molecules 111, thereby ensuring that the liquid crystal layer 100 can change its optical properties in a predetermined manner.

[0044] In the above embodiment, when anti-counterfeiting inspection is performed, orthogonal linear polarizers 20 need to be arranged on both sides of the anti-counterfeiting element 10 so that the observer 40 can perceive the anti-counterfeiting information. This requirement cannot be achieved or cannot be achieved at all in many application environments, so that the anti-counterfeiting element 10 provided in the above embodiment can only be used to a limited extent. Figure 4 , Figure 5 and Figure 7 In some embodiments, the anti-counterfeiting element 10 proposed in the present application further includes a reflective layer 300 , which is disposed on one side of the liquid crystal layer 100 and covers at least a local area of ​​the liquid crystal layer 100 .

[0045] Reference Fig.12 and Fig.13 In practical applications, the reflective layer 300 reflects the incident light passing through the liquid crystal layer 100; thus, when performing anti-counterfeiting inspection, it is only necessary to allow ordinary light to pass through a polarizing film, or no polarizing film is needed and only the light from the mobile phone screen is used for irradiation. The incident light passes through the liquid crystal layer 100 and is reflected back by the reflective layer 300, so that the observer 40 can perform anti-counterfeiting inspection on the same side.

[0046] At the same time, the reflective layer 300 also has a selective effect on the incident light, so that the outgoing light only contains certain bands, so that specific colors can be formed in areas with different effects. When the incident angle of the incident light changes, the color presented to the observer 40 also changes, thereby forming a light-changing effect.

[0047] In some embodiments, the reflective layer 300 is any one or more of a metal reflective layer, a layered interference structure, and a cholesteric liquid crystal layer.

[0048] Specifically, the metal reflective layer is usually made of metal materials with high reflectivity, such as aluminum (Al), silver (Ag), etc. These materials have extremely high reflectivity for light in the visible light band and can effectively reflect light back to the liquid crystal layer or other optical elements. The metal reflective layer has the advantages of simple preparation and low cost. The layered interference structure is usually composed of multiple layers of thin films with different refractive indices and thicknesses. By controlling the parameters of each layer of thin films, a specific reflection and transmission spectrum can be achieved. This structure can produce a very narrow reflection band or transmission band, which is very useful for applications that require precise control of spectral characteristics and can achieve higher optical performance and stability. The cholesteric liquid crystal layer refers to a liquid crystal structure that usually exhibits cholesteric phase liquid crystal behavior (the long axis of the liquid crystal molecules is arranged in a spiral shape). This structure has a selective reflection effect on light, that is, it only reflects light of a specific wavelength and allows light of other wavelengths to pass through. The reflection wavelength of the cholesteric liquid crystal layer can be adjusted by changing the pitch, refractive index and other parameters of the liquid crystal layer itself, so it has very flexible optical properties. Combining the above-mentioned reflective layer structures can achieve more complex optical functions.

[0049] In the above embodiment, the thickness of the liquid crystal layer 100 satisfies the quarter wave plate condition relative to the wavelength of the incident light. Thus, after the incident light is reflected by the reflective layer 300, it will be phase delayed by 90 degrees again, thus completing a complete phase delay of 180 degrees.

[0050] Reference Figure 5 In the above embodiment, the reflective layer 300 is disposed on a side of the liquid crystal layer 100 away from the alignment layer 200 , that is, the reflective layer 300 and the alignment layer 200 are disposed on opposite sides of the liquid crystal layer 100 .

[0051] Reference Figure 6 and Figure 7 In some embodiments, a substrate 400 is further included, and the substrate 400 serves as an installation base, wherein the alignment layer 200 is disposed between the substrate 400 and the liquid crystal layer 100 .

[0052] Some embodiments of the present application also disclose an anti-counterfeiting product, which has an article and the anti-counterfeiting element 10 disclosed in any of the above embodiments, wherein the anti-counterfeiting element 10 is arranged on the article. Therefore, the anti-counterfeiting product has all the beneficial effects disclosed in any of the above embodiments, which will not be repeated here.

[0053] However, it is worth noting that the object can be made of paper or plastic. The anti-counterfeiting element 10 can be used as a window security line, film, label, optical wide strip or transparent window, etc., and can be set on various objects, such as banknotes, certificates or credit cards, etc., which are high-security products and high-value-added products.

[0054] It should be clarified that in the claims, specification and drawings of the present application, the term "multiple" refers to two or more than two. Unless otherwise clearly defined, the orientation or position relationship indicated by the terms "upper" and "lower" is based on the orientation or position relationship shown in the drawings, which is only for the purpose of more conveniently describing the present application and making the description process easier, rather than indicating or implying that the device or element referred to must have the specific orientation described, be constructed and operated in a specific orientation, so these descriptions cannot be understood as limitations on the present application; the terms "connect", "install", "fix" and the like should be understood in a broad sense. For example, "connection" can be a fixed connection between multiple objects, or a detachable connection between multiple objects, or an integral connection; it can be a direct connection between multiple objects, or an indirect connection between multiple objects through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood based on the specific circumstances of the above data.

[0055] In the claims, specification and drawings of the present application, the description of the terms "one embodiment", "some embodiments", "specific embodiments" and the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In the claims, specification and drawings of the present application, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0056] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations, and any modifications, equivalent substitutions, improvements, etc. made should be included in the scope of protection of the present application.

Claims

1. A multi-channel liquid crystal anti-counterfeiting element, characterized in that: include: at least one liquid crystal layer, the liquid crystal layer comprising at least two liquid crystal domains; The liquid crystal molecules in the liquid crystal domains are arranged in the same direction, and the liquid crystal molecules in adjacent liquid crystal domains are arranged in different directions.

2. The multi-channel liquid crystal anti-counterfeiting element according to claim 1, characterized in that: The width of the liquid crystal domain in at least one direction is less than 20 um.

3. The multi-channel liquid crystal anti-counterfeiting element according to claim 1, characterized in that: The liquid crystal molecules are cross-linked with each other.

4. The multi-channel liquid crystal anti-counterfeiting element according to claim 1, characterized in that: The shape of the liquid crystal domain is one or more of a triangle, a square, a rectangle, a circle, a polygon or an irregular shape.

5. The multi-channel liquid crystal anti-counterfeiting element according to claim 1, characterized in that: The thickness of the liquid crystal layer satisfies a half-wave plate condition relative to the wavelength of incident light.

6. The multi-channel liquid crystal anti-counterfeiting element according to any one of claims 1 to 4, characterized in that: It also includes an alignment layer; the alignment layer is arranged on one side of the liquid crystal layer and covers at least a partial area of ​​the liquid crystal layer; the long axis direction of the alignment layer molecules in the alignment layer is parallel or perpendicular to the long axis direction of the liquid crystal molecules covered under the alignment layer.

7. The multi-channel liquid crystal anti-counterfeiting element according to any one of claims 1 to 4, characterized in that: It also includes a reflective layer; the reflective layer is arranged on one side of the liquid crystal layer and covers at least a partial area of ​​the liquid crystal layer.

8. The multi-channel liquid crystal anti-counterfeiting element according to claim 7, characterized in that: The thickness of the liquid crystal layer satisfies a quarter wave plate condition relative to the wavelength of incident light.

9. The multi-channel liquid crystal anti-counterfeiting element according to claim 8, characterized in that: The reflective layer is any one or more of a metal reflective layer, a layered interference structure, and a cholesteric liquid crystal layer.

10. The multi-channel liquid crystal anti-counterfeiting element according to claim 8 or 9, characterized in that: It also includes an orientation layer; the orientation layer is arranged on the other side of the liquid crystal layer away from the reflective layer and covers at least a partial area of ​​the liquid crystal layer; the long axis direction of the orientation layer molecules in the orientation layer is parallel or perpendicular to the long axis direction of the liquid crystal molecules covered under the orientation layer.

11. An anti-counterfeiting product, comprising an article, characterized in that: The article is provided with a multi-channel liquid crystal anti-counterfeiting element as claimed in any one of claims 1 to 10.

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