CN109318618B

CN109318618B - Optical anti-counterfeiting element and anti-counterfeiting product

Info

Publication number: CN109318618B
Application number: CN201710639988.XA
Authority: CN
Inventors: 李欣毅; 朱军
Original assignee: China Banknote Printing and Minting Corp; Zhongchao Special Security Technology Co Ltd
Current assignee: Zhongchao Special Security Technology Co Ltd; China Banknote Printing and Minting Group Co Ltd
Priority date: 2017-07-31
Filing date: 2017-07-31
Publication date: 2020-11-24
Anticipated expiration: 2037-07-31
Also published as: CN109318618A

Abstract

The embodiment of the invention provides an optical anti-counterfeiting element and an optical anti-counterfeiting product using the same, belonging to the field of anti-counterfeiting. The optical security element comprises: a substrate comprising a first surface and a second surface opposite to each other; a sampling layer formed on at least a partial region of the first surface or the second surface; an image layer formed on at least a partial area of the first surface or the second surface, wherein the image layer comprises a plurality of micro-graphic and text units and a background area between the micro-graphic and text units, and the micro-graphic and text units and/or the background area between the micro-graphic and text units are at least partially composed of diffraction microstructures; the sampling layer has a certain correlation with the image layer, so that the sampling layer performs sampling synthesis on the image layer to form one or more macroscopic synthetic images. The optical anti-counterfeiting element has the characteristics of easy identification and difficult counterfeiting.

Description

Optical anti-counterfeiting element and anti-counterfeiting product

Technical Field

The invention relates to the field of optical anti-counterfeiting, in particular to an optical anti-counterfeiting element and an optical anti-counterfeiting product using the same.

Background

In order to prevent counterfeiting by means of scanning, copying and the like, optical anti-counterfeiting technology is widely adopted in various high-safety or high-value-added printed matters such as bank notes, identification cards, product packages and the like, and a very good effect is achieved.

CN 10156640, CN101443692, CN101120139, CN101346244, US5712731, US0034082, US4765656, US4892336, CN1271106, CN1552589 and other patent documents disclose the same type of anti-counterfeiting element with a microlens array and a micro image-text array on two surfaces of a substrate respectively, wherein the micro image-text array is located near a focal plane of the microlens array, and a pattern with a certain depth of field or dynamic effect is reproduced by the moire magnification effect of the microlens array on the micro image-text array.

In order to ensure that the moire magnified pattern is easily recognized under different ambient light conditions, the microimage-text array and the background thereof need to have sufficient contrast of color or brightness, i.e., the microimage-text array needs to be colored. The following coloring methods are currently available in the literature. One class of methods is disclosed in patent documents such as CN 1906547A: forming a recess with a certain depth in the micro-image-text area, filling the coloring material into the recess by using a blade coating process, and basically scraping the redundant material outside the micro-image-text area. In order to realize better coloring, the method has great limitation on the line width and the depression depth of the micrograph and the matching relationship of the line width and the depression depth. Another approach is to use micro-nano structure, for example, patent document US20030179364 discloses that black micro-image-text coloring is realized by using an optical absorption structure with a large aspect ratio, but a single micro-image-text coloring method cannot realize colorized coloring. CN201180040580 multichannel optically variable device discloses that micro-image-text coloring is realized by gravure printing and other modes, but based on the resolution limit of the printing process, only printing of 30 micrometer lines can be realized, and finally the realization effect is single.

Disclosure of Invention

The embodiment of the invention aims to provide a novel optical anti-counterfeiting element with the characteristics of easy identification and difficult counterfeiting and an optical anti-counterfeiting product using the optical anti-counterfeiting element.

In order to achieve the above object, an embodiment of the present invention provides an optical security element, including:

a substrate comprising a first surface and a second surface opposite to each other;

a sampling layer formed on at least a partial region of the first surface or the second surface, the sampling layer including a micro-sampling unit; and

an image layer formed on at least a portion of the first surface or the second surface, the image layer including micro-graphic and text elements and a background region between the micro-graphic and text elements, the micro-graphic and text elements and/or the background region between the micro-graphic and text elements being at least partially composed of diffractive microstructures;

the sampling layer and the image layer have certain relevance, so that the sampling layer performs sampling synthesis on the image layer to form a macroscopic synthetic image.

Meanwhile, when the image layer is observed independently, the diffraction light variable image characteristic different from the sampling composite image is obtained, so that the optical element has two different image effects.

Preferably, the sampling layer and the image layer are on the same or different surfaces of different areas of the substrate, respectively.

Preferably, the sampling layer and the image layer are on different surfaces of the same area of the substrate, respectively.

Preferably, the sampling layer is formed on the first surface, the image layer is formed on the second surface, and the sampling layer and the image layer are respectively arranged on the same area of the substrate, so that the synthetic image formed by sampling can be observed above the first surface, and simultaneously, the image layer is independently observed above the second surface, and the diffraction light variable image characteristics different from the synthetic image can be observed, so that the front side and the back side of the optical anti-counterfeiting element have different image effects.

Preferably, the sampling layer and the image layer are formed on different areas of the first surface, and when the optical security element is folded such that the image layer is located near the focal plane of the sampling layer, approximately twice the thickness of the substrate, the sampled composite image is viewable over the sampling layer, while diffractive optically variable image features distinguishable from the sampled composite image are viewable over the image layer such that the optical element has two different image effects.

Preferably, the sampling layer is formed on the first surface, the image layer is formed on the second surface, the sampling layer and the image layer are respectively on different areas of the substrate, and when the optical security element is folded such that the image layer is located near the focal plane of the sampling layer, approximately the thickness of the substrate, the sampling-formed composite image is observable on the sampling layer, while above the image layer, diffractive light-variable image features distinguishable from the sampling composite image are observable such that the optical element has two different image effects.

Preferably, the substrate has a transparent or translucent window so that the sampling layer can sample and synthesize the image layer through the substrate.

Preferably, the sampling layer is composed of two-dimensional microlens array focusing elements or one-dimensional microlens array focusing elements.

Preferably, the image layer is periodic or locally periodic in microscopic arrangement in at least one dimension.

Preferably, the image layers are non-periodic and/or non-axisymmetric in microscopic arrangement.

Preferably, the arrangement period of the micro sampling units is 20 to 500 micrometers.

Preferably, the arrangement period of the micro sampling units is 20 to 100 micrometers.

Preferably, the focal length of the micro-sampling units of the sampling layer is 10 micrometers to 2 millimeters.

Preferably, the focal length of the micro-sampling units of the sampling layer is 10 to 300 micrometers.

In another aspect, the invention provides an optical anti-counterfeiting product, which comprises the optical anti-counterfeiting element.

According to the technical scheme, when the image layer is sampled through the sampling layer, one or more synthesized image characteristics are formed; when the image layer is observed independently, the image characteristics different from the sampling synthesis can be observed, so that the optical anti-counterfeiting element has two completely different optical visual effects simultaneously, and has the characteristics of easy identification and difficult counterfeiting.

In particular, the image layer text elements and/or the background areas between the text elements are at least partially composed of diffractive microstructures. When the image layer is sampled through the sampling layer, one or more synthetic image features with diffraction holographic effect are formed; when the image layers are observed independently, visible diffraction light variable image characteristics different from sampling composition can be observed. The advantage is that a user can observe two-color or even multicolor diffraction dynamic optical characteristics through the sampling layer; different diffraction optical characteristics can be directly observed from the image layer, so that the optical visual effect is improved, and the imitation difficulty is also improved.

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

Drawings

The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the embodiments of the invention without limiting the embodiments of the invention. In the drawings:

FIG. 1 is a cross-sectional view of an optical security element according to one embodiment of the present invention;

FIGS. 2a-b are cross-sectional views and fold-checking cross-sectional views of an optical security element according to another embodiment of the present invention;

FIGS. 3a-b are cross-sectional views and fold-checking cross-sectional views of an optical security element according to still another embodiment of the present invention;

FIGS. 4a-b are top views of a sampling layer and an image layer, respectively, of an optical security element according to an embodiment of the present invention;

FIGS. 5a-e are several views of the partial area of the image layer of FIG. 4b consisting of diffractive structures, respectively;

6a-b are top views of a sampling layer and an image layer, respectively, of an optical security element according to another embodiment of the present invention;

FIGS. 7a-c illustrate several ways of forming diffractive structures in partial areas of the image layer corresponding to FIG. 6b, respectively;

FIG. 8 is a top view of an image layer of an optical security element according to yet another embodiment of the present invention;

FIGS. 9a-d illustrate several ways of forming diffractive structures corresponding to portions of the image layer of FIG. 8;

FIG. 10 is a top view of an image layer of an optical security element according to yet another embodiment of the present invention;

FIGS. 11a-c are several views, respectively, of some regions in the image layer corresponding to FIG. 10, consisting of diffractive structures; and

fig. 12 is a top view of an image layer of an optical security element according to yet another embodiment of the present invention.

Description of the reference numerals

1 optical anti-counterfeiting element 2 base material

21 sampling layer 22 image layer

31 first surface 32 second surface

Detailed Description

The optical security element and the product using the same according to the present invention will be described in detail below with reference to the accompanying drawings in order to better understand the idea of the present invention. It should be understood that the drawings and detailed description are only illustrative of preferred embodiments of the invention and are not intended to limit the scope of the invention in any way.

As shown in fig. 1, an optical security element 1 according to an embodiment of the present invention includes: the substrate 2 comprises a first surface 31 and a second surface 32 which are opposite to each other, and a sampling layer 21 formed on the first surface 31 and an image layer 22 formed on the second surface, wherein the image layers 22 are associated with the sampling layer 21 and are respectively arranged on different surfaces of the same area of the substrate. The sampling layer is composed of a micro lens array, the focal length of the micro lens array is matched with the thickness of the base material, and the image layer is composed of diffraction microstructures at least in partial areas. When the image layer is sampled through the sampling layer, one or more synthesized image features are formed; when the image layer is observed independently, the image characteristics different from the sampling synthesis can be observed, so that the optical anti-counterfeiting element has two completely different optical visual effects simultaneously, and has the characteristics of easy identification and difficult counterfeiting.

Referring to fig. 2, which is a cross-sectional view 2a and a cross-sectional view 2b of a fold-check of an optical security element according to another embodiment of the present invention, the image layer 22 is associated with the sampling layer 21 and is respectively located at different areas of the same surface of the substrate, and when the optical element is folded such that the image layer 22 is located near the focal plane of the sampling layer 21, a composite image formed by sampling can be observed above the sampling layer.

As shown in fig. 3, the image layer 22 and the sampling layer 21 are on different areas of different surfaces of the substrate, respectively, and when the optical element is folded such that the image layer 22 is located near the focal plane of the sampling layer 21, a composite image formed by sampling is observed over the sampling layer.

Preferably, the substrate 2 is transparent or translucent (e.g., polyester-based plastic film) so that the sampling layer 21 can sample and synthesize the image layer 22 through the substrate.

Preferably, the substrate 2 has one or more transparent or translucent windows so that the sampling layer 21 can sample the image layer 22 through the substrate.

Preferably, the sampling layer 21 is composed of two-dimensional microlens array focusing elements. The micro-lens array focusing elements are arranged in at least one of a two-dimensional square arrangement mode, a rectangular arrangement mode and a hexagonal arrangement mode. For example, the sampling layer 21 is composed of a spherical microlens array, and an original plate can be obtained by optical or electron beam gray scale exposure, mask exposure, photoresist hot melting, and the like, and mass replication can be performed by processing methods such as ultraviolet casting, mold pressing, and the like.

Preferably, the sampling layer 21 is composed of a one-dimensional microlens array focusing element. The focusing elements of the micro lens array are arranged in a one-dimensional column shape. For example, the sampling layer 21 is composed of a cylindrical microlens array, and an original plate can be obtained by optical or electron beam gray scale exposure, mask exposure, photoresist hot melting, and the like, and mass replication can be performed by processing methods such as ultraviolet casting, mold pressing, and the like.

Preferably, the image layer 22 is periodic or locally periodic in microscopic arrangement in at least one dimension. The optical sampling device has the advantages that the optical design and the manufacturing are easier, and the optical characteristics of dynamic sense, translation, rotation and the like can be realized through sampling by the sampling layer 21.

Preferably, the image layer 22 is non-periodic and/or non-axisymmetric in microscopic arrangement. The method has the advantages that through a complex optical design and manufacturing mode, complex and more difficult-to-imitate optical characteristics such as double/multiple channels, deformation, rotation, specific action and the like are realized.

The arrangement period of the micro sampling units of the sampling layer 21 is 20 to 500 micrometers, and preferably 20 to 100 micrometers. The arrangement period of the micro sampling units 21 determines the size of the micro sampling units to some extent, and further determines the focal length thereof. For example, if the micro-sampling unit is a spherical microlens array (see fig. 4a) with a period of 100 microns and a spacing of 5 microns, the spherical microlens size is 95 microns and the focal length is 90 microns, which would require a matching substrate thickness of about 90 microns in the optical element embodiment shown in fig. 1.

The focal length of the micro-sampling units of the sampling layer 21 is 10 micrometers to 2 millimeters, preferably 10 micrometers to 300 micrometers. The focal length of the micro-sampling unit is matched with the optical element substrate, such as the optical element shown in fig. 1 and 3, and the focal length is basically the same as the thickness of the substrate, so that the image layer can be clearly sampled; the optical element of fig. 2 should have a focal length that is substantially the same as twice the thickness of the substrate so that when the optical element is folded, the two substrates abut each other and the image layer 22 is located just near the focal plane of the sampling layer so as to be clearly sampled.

The image layer 22 includes diffractive microstructures that form diffractive optically variable features for directly forming a macroscopic viewing image without passing through the sampling layer, and for forming a macroscopic viewing image with diffractive optical variations through the sampling layer. The advantage is that a user can observe two-color or even multicolor diffraction dynamic optical characteristics through the sampling layer; different diffraction optical characteristics can be directly observed from the image layer, so that the optical visual effect is improved, and the imitation difficulty is also improved. The image layer 22 may be obtained as an original by optical or electron beam exposure, mask exposure, etc., and may be mass-replicated by processing such as uv casting and embossing. Several implementations are described below in detail with reference to the figures.

In practical applications, the image layer 22 of the optical security element may be selected from the schemes including, but not limited to, those listed below. For example, fig. 4, 6, and 8 each list top views of the sampling layer and the image layer of three optical anti-counterfeiting elements, fig. 5 lists addition of different diffractive microstructures to the image layer corresponding to a two-dimensional microlens array, fig. 7 lists addition of different diffractive microstructures to the image layer corresponding to a one-dimensional lenticular lens array, fig. 9 and 11 lists addition of different diffractive microstructures to the image layer containing two microimage regions, and fig. 12 lists addition of diffractive microstructures to a macroscopic pattern (a five-pointed star region) in addition to the above cases.

Wherein the different periodic diffractive microstructures form different color pattern effects. The different azimuthal angle diffractive microstructures form a pattern effect for different viewing angles. For example, the microimage of fig. 5e and the background are added with diffraction microstructures which are 90 degrees each other, and when the microimage is shiny, the background is dark, and when the optical element is rotated by 90 degrees, the background is shiny, and the microimage is dark, observed through the sampling layer; direct viewing of the microimage region also enables a macroscopic diffractive optical feature to be observed. For another example, as shown in fig. 9B, when diffractive microstructures with different periods are added to the microimages a and B, sampling is performed through the micro-sampling layer, and a shows red, while B shows green; direct viewing of the microimage region enables a red and green fitted diffractive optical feature to be observed. As another example 11B, which shows the image layer corresponding to the cylindrical lens micro-sampling unit, the two examples are integrated, and by sampling observation, a and B with different colors and a dark background can be observed at the same time, and when the optical element is rotated by 90 degrees, a and B become dark, the background becomes bright; when the micro-image area is directly observed, diffraction optical characteristics with different colors can be observed in two macro areas A and B, when the optical element is rotated by 90 degrees, the A and B become dark, and meanwhile, the background becomes a bright single diffraction optical characteristic. For another example, as shown in fig. 12, in addition to the diffractive microstructures added to the micro images a and B, the diffractive microstructures are added to the macroscopic five-pointed star region, and the macroscopic five-pointed star image can be observed by directly observing the micro image region without affecting the sampling observation of the micro image. The optical anti-counterfeiting element can be used for high-safety products and high-value-added products such as plastic banknotes, paper banknote safety lines, wide strips, labels and marks, and various packaging papers, packaging boxes and the like.

The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, numerous simple modifications can be made to the technical solution of the invention, including combinations of the individual specific technical features in any suitable way. The invention is not described in detail in order to avoid unnecessary repetition. Such simple modifications and combinations should be considered within the scope of the present disclosure as well.

Claims

1. An optical security element, comprising:

wherein the sampling layer has a certain correlation with the image layer, so that the sampling layer performs sampling synthesis on the image layer to form a macroscopic synthetic image,

wherein the diffractive microstructure forms diffractive optically variable features for directly forming a macroscopic viewing image without passing through the sampling layer, and for forming a macroscopic viewing image with diffractive optical variations through the sampling layer.

2. An optical security element according to claim 1, wherein the sampling layer and the image layer are on the same or different surfaces of different regions of the substrate.

3. An optical security element according to claim 1, wherein the sampling layer and the image layer are on different surfaces of the same area of the substrate.

4. An optical security element according to claim 1, wherein the sampling layer is formed on the first surface and the image layer is formed on the second surface, the sampling layer and the image layer being in the same region of the substrate such that the macroscopic composite image is viewable above the first surface, and the image layer is independently viewable above the second surface to enable viewing of the diffractive optically variable image features distinct from the macroscopic composite image such that the optical security element has different image effects when viewed from the front and back sides.

5. The optical security element according to claim 1, wherein the sampling layer and the image layer are formed on different areas of the first surface, and when the optical security element is folded such that the image layer is located near a focal plane of the sampling layer, the image layer is spaced from the focal plane by twice the thickness of the substrate, the macroscopic composite image is viewable above the sampling layer, and the diffractive light-variable image feature distinct from the macroscopic composite image is viewable above the image layer such that the optical security element has two different image effects.

6. The optical security element according to claim 1, wherein the sampling layer is formed on the first surface and the image layer is formed on the second surface, the sampling layer and the image layer are respectively on different regions of the substrate, and when the optical security element is folded such that the image layer is located near a focal plane of the sampling layer, the image layer is spaced from the focal plane by a thickness of the substrate, the macroscopic composite image is observable on the sampling layer, and the diffractive optically variable image feature distinct from the macroscopic composite image is observable above the image layer, such that the optical security element has two different image effects.

7. An optical security element according to claim 1, wherein the substrate has a transparent or translucent window such that the sampling layer is able to sample the image layer through the substrate.

8. An optical security element according to claim 1, wherein the sampling layer is composed of two-dimensional microlens array focusing elements or one-dimensional microlens array focusing elements.

9. An optical security element according to claim 1, wherein the image layer is periodic or locally periodic in microscopic arrangement in at least one dimension.

10. An optical security element according to claim 1, wherein the image layer is non-periodic and/or non-axisymmetric in microscopic arrangement.

11. An optical security element according to claim 1, wherein the micro-sampling units are arranged with a period of 20 to 500 microns.

12. An optical security element according to claim 1, wherein the micro-sampling units are arranged with a period of 20 to 100 microns.

13. An optical security element according to claim 1, wherein the focal length of the micro-sampling cells of the sampling layer is from 10 μm to 2 mm.

14. An optical security element according to claim 1, wherein the focal length of the micro-sampling cells of the sampling layer is from 10 to 300 microns.

15. A security product comprising an optical security element according to any one of claims 1 to 14.