WO2011090407A1

WO2011090407A1 - Optical security element, method for manufacturing same and verification and self-verification device

Info

Publication number: WO2011090407A1
Application number: PCT/RU2011/000019
Authority: WO
Inventors: Андрей Львович КАРАСЕВ; Анатолий Вениаминович ВАННИКОВ; Людмила Григорьевна КАРАСЕВА
Original assignee: Открытое Акционерное Общество "Научно-Производственное Объединение "Криптен"
Priority date: 2010-01-21
Filing date: 2011-01-19
Publication date: 2011-07-28
Also published as: EA201000285A1; EA014380B1

Abstract

The invention relates to the field of protection against counterfeit and verification of the authenticity of valuable documents. The problem addressed by the invention consists in increasing the efficiency of the verification and the degree of protection against counterfeit. When manufacturing an optical security element, a hidden image is printed on each of the sides of a thin-film polarizer using the direct printing method with the aid of a colorless liquid composition and said image is cured. Then, a portion for ensuring optical anisotropy is structured so as to give a hidden image which remains invisible to the naked eye and is observed with sharp contrast in polarized light, and a thin transparent protective layer is applied over the whole surface of the working side. When verifying the authenticity of a document with a security element, each of the sides of said document is arranged alternately on a reflecting element and is exposed to natural non-polarized light.

Description

OPTICAL PROTECTIVE ELEMENT, METHOD FOR ITS MANUFACTURE AND DEVICE FOR VERIFICATION AND SELF-VERIFICATION

Technical field

The invention relates to the field of protection against falsification and authentication of valuable documents, in particular, to the manufacture and production of optical security elements that carry a latent image that is practically invisible in natural light to the naked eye and visualized when observed using simple devices built into the protected object.

State of the art

The objective of the present invention is the creation of operational, i.e. non-instrumental method (verification can be carried out at any time in any place without involving any equipment), a protective optical device with a high degree of protection against counterfeiting, which is also evidence of the authenticity of the protected object. In this case, the security feature is invisible in natural light to the naked eye and is visualized with high contrast using only one visualization tool that allows machine verification, and which, among other things, can be included in the protected object. Moreover, each protective element, which is a thin layer of transparent material, can carry two or more protective features of the same or different physical nature, invisible under normal conditions and visualized independently of each other, which significantly increases the level of protection. The tool is intended to protect against counterfeiting and as a sign of authenticity of banknotes, passports and other valuable documents, plastic cards and other similar objects, hereinafter - valuable documents. The main method of using the inventive protective agent is in the form of a transparent window in a protected valuable document.

At present, for protection against counterfeiting and as authenticity signs, (in addition to various means of printing protection) protection means and authenticity signs are used, which are built into the protected product in the form of a transparent or translucent window that carries one or more security features, such as various visible images, a color-changing effect in transmitted and reflected light, diffraction, holographic and other optical effects. Among the protective elements with variable optical properties, the most difficult to reproduce, are elements containing latent images that are visible only in certain lighting conditions or when using special filters.

In the international publication WO / 2007/137334 it is proposed to use liquid crystal layers to form a polarization structure - a standard transparent design containing a polarized image, however, this method of verification and self-verification has not been proposed and, moreover, this protective agent has only one level of protection, those. carries only one security feature - one latent image.

Patent EA 01 1838 proposes a method for forming an invisible hidden polarized image by direct printing with a colorless liquid composition on a thin transparent layer, which, however, has only one level of hidden protection and a standard two-element imaging device.

The concept of using a polarized latent image in a transparent window (with both one and two independent latent images) of a valuable document was first proposed in patent US 6124970 publ. 09/26/2000, MriKG02B 27/28. However, the described tool consists of three polymer layers, has a significant thickness, and, moreover, effective methods of image visualization have not been proposed.

Closest to the claimed method is the method described in international publication WO 03/006261, which proposes a method of manufacturing a security element containing two independent hidden polarized images and a method for its visualization. The disadvantages of the method include the three-layer structure and the associated significant thickness of the protective agent that does not allow the use of the proposed tool as a protective window in a banknote or document page; a two-element visualization device, which is not applicable for machine verification, as well as self-verification, while a single-element visualization device allows machine verification, and in the case of a single-element visualization device built into the protected product, and self-verification. In addition, in the cases presented, latent polarized images are formed in a transparent polymer layer prepared in a special way and then attached to two sides of the polarizer, resulting in a thick, more than 100 μm, mechanically unstable element - this is the main disadvantage that does not allow practical use data of the invention.

The objective of the present invention is to provide a method for forming two independent latent polarized images in a single layer, mechanical properties compatible with the material of a valuable document, transparent material, invisible in natural light to the naked eye and independently visualized with high contrast using a single visualizing element - a mirror, which significantly increases the efficiency of verification and the level of protection against counterfeiting and copying.

SUMMARY OF THE INVENTION

According to a first aspect of the invention, a method for manufacturing an optical security element is disclosed, which comprises the following steps:

a) provide a transparent medium, which is a thin-film polarizer having two working sides, each of which is used to form independent latent images;

b) imprint the latent image on at least one area on the first working side of the medium by direct printing using a colorless liquid composition and solidify it;

C) carry out the structuring in a predetermined direction to a predetermined depth of at least one area, on the first working side of the carrier, carrying a latent image, to provide optical anisotropy in the specified area, as a result, receive a latent polarized image, which remains invisible when observed with the naked eye and is clearly contrasted in polarized light;

g) apply a thin transparent protective layer over the entire surface of the first working side of the protective polarizing element;

e) imprint the latent image on at least one area on the back of the carrier, which is the second working side, by direct printing using a colorless liquid composition and cure it; e) carry out structuring in a predetermined direction to a predetermined depth of at least one area, on the second working side of the carrier carrying a latent image, to provide optical anisotropy in the specified area, as a result, a latent polarized image is obtained, which remains invisible when observed to the naked eye and is observed in clear contrast in polarized light;

g) apply a thin transparent protective layer over the entire surface of the second working side of the protective polarizing element;

In this case, a thin-film linear polarizer or

thin film circular polarizer.

Moreover, the transparent colorless composition used to form latent images is either a 5-30% solution of the polymer or a photocurable liquid crystal composition in an inorganic or organic solvent, or an emulsion containing 10-30% of the polymer;

In addition, according to the method, provide for the formation of at least one luminescent latent image on top of at least one of the latent polarization images.

In this case, thin transparent protective layers are mechanically strong thin varnish coatings.

In addition, according to the first aspect, the thin transparent protective layers are mechanically strong thin polymer films, containing transparent holographic images or invisible luminescent images.

Thus, according to the method, the protective layer is a thin transparent varnish coating with a thickness of about 1 μm, which may contain a transparent multicolor visible or holographic image or latent images of a different physical nature. For example, using the properties of the polarizer that are barrier to UV light, two independent hidden invisible luminescent images can be imprinted separately on both of its working sides on top of latent polarized images.

At the same time, latent images that are applied to the medium by direct printing can be applied using one of the following methods: flexographic printing, intaglio printing, screen printing.

In addition, the optical security element is part of a banknote, passport page, other valuable documents or plastic cards.

In addition, according to the first aspect, structuring in a predetermined direction to a predetermined depth of from 0.3 to 0.5 μm of at least one portion on the first and second working side of the carrier is carried out. At the same time, the structuring of the obtained images is a mechanical treatment using felt-covered rolls, or a thermomechanical action - applying strokes in the machine direction, i.e. in the direction of movement of the tape using a plotter direct image output or thermal printer.

In this case, the protective element thus formed withstands a temperature of 180% C.

It should be noted that the security element made according to the method according to the first aspect of the invention combines two verification steps: operational - self-verification using separate visualization of latent polarized images and instrumental - separate visualization of two independent luminescent images, has a high level of protection and very high stability ^, such a protective tool against copying and imitation. According to a second aspect of the invention, there is provided a method for verifying the authenticity of a document with a protective optical element made in accordance with the method described above, using at least one optical reflective element for visualizing latent polarized images and comprising the steps of: a) placing the document with the protective optical element on the optical reflective element so that the first working side of the protective element lies on the specified reflective element,

b) illuminate the second working side of the specified protective optical element with a reflective element with natural unpolarized light, providing visualization of the latent image on the first working side, while the latent image on the second working side remains invisible;

c) place a document with a protective optical element on the optical reflective element so that the second working side of the protective element lies on the specified reflective element,

d) illuminate the first working side of the specified protective optical element with a reflective element with natural unpolarized light, providing visualization of the latent image on the second working side, while the latent image on the first working side remains invisible;

e) determine the authenticity of the document by visualized latent images on the first and second working sides of the security element.

According to a second aspect of the invention, at least one optical reflective element is used to visualize latent images, which provides the necessary twofold passage of polarized light through the visualized latent image.

In addition, visualization tools in the form of reflective elements can be built into the protected object, which allows self-verification of the authenticity of the protected object, and the reflective elements can be part of the design of a valuable document.

In this case, the protected document subject to verification may be a valuable document in the form of a banknote with a security element, which is used as a transparent window in at least a part of the banknote, this transparent window is a medium on each working side, which is imprinted with at least one latent image, and on each side of a valuable document in the form of a banknote two reflective elements are embedded in such a way that when the document is folded, the transparent window containing the latent images is combined with a reflective element either one or the other with its working side.

In addition, the document to be verified may be a valuable document, which is a structure of several pages in the form of a passport or a similar document containing a security element used as a transparent page of the specified document, while the security element is a transparent medium having two working sides and bearing latent images formed on each of these sides, as well as two reflective elements located on pages adjacent to a transparent page carrying a ytye image for visualizing the latent images on each side of the transparent work page.

According to a third aspect of the invention, an optical protective element is provided, consisting of a transparent carrier, which is a thin-film polarizer, on each working side of which are imprinted hidden, invisible in natural light images, which, in turn, are coated with a transparent protective layer, and made in accordance with paragraphs . 1-1 1.

According to a fourth aspect of the invention, there is provided a valuable document comprising a security element used in the form of a transparent window in at least a portion of a valuable document and made according to the method of claims. 1-1 1, as well as two reflective elements, the protective element being a transparent medium having two working sides, and latent images formed on each of these sides, and these two reflecting elements are located on a valuable document with the possibility of combining it with a transparent window to provide visualization of the latent image on one of the specified working sides of the transparent medium, provided that the image on the other back of the specified transparent medium remains invisible. Moreover, the valuable document according to the fourth aspect can be a transparent plastic card, banknote or plastic banknote.

According to a fifth aspect of the invention, there is provided a valuable document that is a multi-page structure in the form of a passport or similar document containing a security element used as a transparent window in at least a portion of at least one page of said document and made according to the method of the first aspect of the invention, the security element being a transparent carrier having two working sides and latent images formed on each of said sides, as well as at least two reflective elements located on pages adjacent to the page with a transparent window carrying hidden images, while these reflective elements are arranged in such a way that they provide separate visualization of hidden images located on both working sides of the protective element.

In addition, in the indicated valuable document, a transparent window carrying hidden images may occupy the entire page.

Description of the figures of the drawings

Signs, elements and advantages of the invention arise from the following description of embodiments of the invention with reference to the accompanying drawings, in which:

Figure 1 - view of the protective polarizing element in cross section. Figure 2 - method for visualizing independent latent images - the image on the first working side of the element.

Fig. 3 - method of visualization of independent latent images - the image on the second working side of the element.

Figure 4 - material design with a built-in security element and means of self-verification for the manufacture of banknotes.

5 is a method of self-verification of the authenticity of banknotes - the image on the first side of the transparent window of the banknote.

6 is a method of self-verification of the authenticity of banknotes - image on the second side of the transparent banknote window.

Description of a preferred embodiment of the invention

According to a method for manufacturing an optical security element, a thin-film linear or circular polarizer is selected as the transparent carrier 1. The first latent image 2 is imprinted on at least one portion of one of its sides, the second latent image 3 is imprinted on the other working side of the medium in the same way. Both latent images 2 and 3 are imprinted by direct printing using a liquid transparent colorless composition, which is either 5 A 30% solution of the polymer or photocurable liquid crystal composition in an inorganic or organic solvent, or an emulsion containing 10-30% of the polymer. The above ranges of polymer content in liquid compositions are generally accepted in industry and laboratory practice to produce thin transparent polymer films. A fairly complete description of the methods is given in the monograph: N.V. Suikovskaya, “Chemical methods for the production of thin transparent films”, Ed. “Chemistry”, Leningrad, 1971

After appropriate surface treatment - mechanical processing using felt-covered rolls, or thermomechanical processing using the thermal printer's writing heads or direct image output plotter - the elements of both latent images (letters, numbers, logos, ornaments, etc.) are anisotropic transparent polymer layers with a thickness of 1-3 microns. Processing is carried out in the direction of movement of the tape to a depth of 0.3-0.5 microns.

Imprinting a latent image can be done using any printing method: flexographic, offset, deep, screen, etc.

The transparent carrier 1 of the images is a thin-film transparent polarizer. It can be either a thin-film symmetric linear polarizer - in this case, the direction of the axis of polarization should be an angle of about ± 45 ° with the direction of the anisotropy of the image; or a symmetric circular polarizer - in this case, the visibility of latent images during visualization does not depend on the relative orientation of the polarizer and latent images; either unbalanced circular / linear polarizer.

As a result, the security element (FIG. 1) is a transparent film that carries two images invisible to the naked eye, located on different working sides of the carrier.

To implement a method for verifying the authenticity of a document with a security element and for performing separate and independent visualization of latent images located on two sides of the transparent medium 1, at least one reflective element 4 is required. Under conditions of natural unpolarized light, when the reflective element 4 is attached to the first working element side of the element (Figure 2), the first latent image 2 is visualized, the observer sees it in the direction of arrow 5, the second image 3 remains invisible. When a reflector is attached to the second working side of the element (Fig. 3), the second latent image 3 is visualized, the observer sees it in the direction of arrow 5, while the first image 2 remains invisible.

The inventive security element may be part of the material for the manufacture of banknotes 6. As a rule, transparent elements bearing security features are embedded in paper or other material for banknotes in the form of a window 7 (Figure 4). Reflective elements 8 and 9, deposited on opposite sides of the material 6, serve for separate and independent visualization of both latent images when the banknote is bent in one direction or another, Figures 5 and 6 show the process of verification (self-verification) of the banknote. Visualizing reflective elements can be part of the design of a valuable document.

The use of the inventive polarization element to protect against forgery of a passport or other similar document will be described below. The security structure of a valuable document in the form of a passport consists of at least one page, and a transparent window is embedded in at least one part of one of the pages of the specified document and is a transparent carrier of protective hidden images, while the specified carrier has two working sides, each from the sides of which latent images are formed, and on adjacent to the page of the document with a transparent window located or applied by any other known method, at least two visualizing reflective elements. When the page with the window lies on the page with the first reflective element, the first hidden image is visualized, the second remains invisible. When the page with the window lies on the page with the second reflective element, the second latent image is visualized, the first remains invisible, thus, this provides separate visualization of latent images located on both working sides of the security element.

The presence of both a security element and a visualization tool as part of a valuable document allows you to quickly establish the authenticity of a valuable document at any time at any time without involving any equipment - this is a process of self-verification, a process of initial screening of fake copies.

Industrial applicability

The claimed invention can be used to protect against falsification of valuable documents: passports, vouchers, banknotes, stocks, checkbooks, as well as plastic cards and to identify the authenticity of these documents.

Claims

CLAIM

1. A method of manufacturing an optical security element, which contains the following steps:

c) structuring in a predetermined direction to a predetermined depth of at least one region, on the first working side of the carrier carrying the latent image, to provide optical anisotropy in the specified region, as a result, a latent polarized image is obtained, which remains invisible when observing it to the naked eye and is observed in clear contrast in polarized light,

e) imprint the latent image on at least one area on the back of the carrier, which is the second working side, by direct printing using a colorless liquid composition and cure it; e) carry out structuring in a predetermined direction to a predetermined depth of at least one area, on the second working side of the carrier carrying a latent image, to provide optical anisotropy in the specified area, as a result, a latent polarized image is obtained, which remains invisible when observed to the naked eye and is observed in clear contrast in polarized light,

2. The method according to p. 1, in which a thin-film linear polarizer is used as a carrier.

3. The method of claim 1, wherein the carrier is used thin film circular polarizer.

4. The method according to claim 1, in which the liquid transparent colorless composition is either a 5-30% solution of the polymer or a photocurable liquid crystal composition in an inorganic or organic solvent, or an emulsion containing 10-30% of the polymer.

5. The method according to claim 1, in which at least one luminescent latent image is formed on top of at least one of the latent polarization images.

6. The method according to claim 1, in which the thin transparent protective layers are mechanically strong thin varnish coatings.

7. The method according to claim 1, in which the thin transparent protective layers are mechanically strong thin polymer films containing transparent holographic images.

8. The method of claim 1, wherein the thin transparent protective layers are mechanically strong thin polymer films containing invisible luminescent images.

9. The method according to p. 1, in which latent images are applied to a medium by direct printing from a number of: flexographic printing, intaglio printing, screen printing.

10. The method according to claim 1, in which the optical security element is part of a banknote, passport page, other valuable documents, a plastic card.

1 1. The method according to claim 1, in which structuring is carried out in a predetermined direction to a predetermined depth of from 0.3 to 0.5 μm of at least one portion on the first and second working side of the carrier.

12. A method of verifying the authenticity of a document with a protective optical element, made according to the method according to paragraphs. 1-11, and using for visualization of latent polarized images at least one optical reflective element and comprising stages, according to which: a) place a document with a protective optical element on the optical reflective element so that the first working side of the protective element lies on the specified reflective element b) illuminate the second working side of the specified protective optical element with a reflective element with natural unpolarized light, providing visualization of the latent image on the first working side, while the latent image on the second working side remains invisible;

13. The verification method according to claim 12, wherein the document to be verified is a valuable document in the form of a banknote with a security element, which is used as a transparent window in at least a part of the banknote, said transparent window being a carrier on each the working side of which is imprinted with at least one latent image, and on each side of a valuable document in the form of a banknote two reflective elements are embedded in such a way that when the document is bent, a transparent window containing Tide image is aligned with the reflective element of either one or the other of its working side.

14. The verification method according to claim 12, in which the document to be verified is a valuable document, which is a structure of several pages in the form of a passport or similar document containing a security element used as a transparent page of the specified document, while the security element represents a transparent carrier having two working sides and carrying latent images formed on each of these sides, as well as two reflective elements located on pages adjacent to the transparency a page containing latent images to provide visualization of latent images on each working side of a transparent page.

15. An optical protective element consisting of a transparent carrier, which is a thin-film polarizer, on each working side of which are imprinted hidden, invisible in natural light images, which, in turn, are covered with a transparent protective layer, and made in accordance with 1-1 1.

16. A valuable document containing a security element used in the form of a transparent window in at least part of a valuable document and made according to the method according to claims 1-1, as well as two reflective elements, wherein the security element is a transparent medium having two working sides and latent images formed on each of these sides, and these two reflective elements are located on a valuable document with the possibility of combining with a transparent window to provide visualization of the latent image on one second sides of said transparent working medium under the condition that the image on the reverse side of the other of said transparent carrier remains invisible.

17 Valuable document according to clause 16, which is a transparent plastic card, banknote or plastic banknote.

18. Valuable document, which is a structure of several pages in the form of a passport or similar document containing a security element used in the form of a transparent window in at least part of at least one page of the specified document and made according to the method according to claims 1- 1 1, wherein the security element is a transparent medium having two working sides, and latent images formed on each of these sides, as well as at least two reflective elements located on the pages, adjacent to the page, with a transparent window carrying hidden images, while these reflective elements are arranged in such a way as to provide separate visualization of hidden images located on both working sides of the protective element.

19. A valuable document according to claim 18, in which a transparent window carrying hidden images can occupy the entire page.