WO2012015330A1

WO2012015330A1 - Multilayered security element with variable optical effect and a counterfeit-proof document

Info

Publication number: WO2012015330A1
Application number: PCT/RU2010/000732
Authority: WO
Inventors: Аркадий Владимирович ТРАЧУК; Андрей Валерьевич ЧЕГЛАКОВ; Андрей Борисович КУРЯТНИКОВ; Александр Георгиевич ПИСАРЕВ; Михаил Анатольевич OCTPEPOB; Юрий Васильевич ПАВЛОВ; Елена Михайловна ФЕДОРОВА; Елена Самуиловна ТУРКИНА; Анатолий Павлович ГУБАРЕВ
Original assignee: Федеральное Государственное Унитарное Предприятие "Гознак" (Фгуп "Гознак")
Priority date: 2010-07-29
Filing date: 2010-12-06
Publication date: 2012-02-02
Also published as: CN103119638B; EP2600332A1; EP2600332A4; RU2430836C1; CN103119638A; EP2600332B1

Abstract

The invention relates to counterfeit-proof documents with multilayered security markings. The multilayered security element comprises a flexible base layer with optically variable structures containing two or more groups of recurring images which shift and/or change as the viewing angle changes. The optically variable structures are formed in such a way that when the viewing angle changes, different groups of images move relative to each other. The invention makes it possible to enhance the security of items by means of a novel optical effect which renders the secure object more readily identifiable and is based on the observation of the reciprocal movement of images when the viewing angle changes.

Description

MULTI-LAYER PROTECTIVE ELEMENT WITH VARIABLE OPTICAL EFFECT AND FORGET PROTECTED DOCUMENT

The invention relates to security documents with multilayer security markings. Protected documents can be valuable documents, such as checks, stocks, banknotes, excise stamps, special federal stamps and identification documents, such as passports, identification cards, etc. State of the art

In order to make tampering and counterfeiting more difficult, security documents are usually provided with security markings such as watermarks, holograms, diffraction-refractive nanograms, fluorescent signs, security threads, etc.

Many standard signs, however, have the disadvantage that they can be made or easily counterfeited and / or that they can hardly be certified without technical equipment by a layman. The present invention is directed to the creation of such protective markings that are able to provide unusual optical effects that occur without the use of special equipment.

Protective elements based on micro-lens raster structures are known. Optical images in such protective elements are formed as a result of superposition of two or more microraster structures, one or more of which is microlens gratings, the others are raster structures made with the same spatial periods as microlens gratings, in the nodes of which there are repeating micro images made using printing technologies or precision stamping technologies. In these cases, the so-called moire effects are used. There are several types of such effects. Moiré effects with orthogonal or collinear (parallel) parallax shift of the observed magnified optical images. This type of moire effects is characteristic of microraster structures with spherical or pseudo-spherical lenses in the nodes of the raster lattices.

A micro-optical system is described (US 2005/0180020 A1, 08/18/2005), in the form of a polymer film, which when viewed with the naked eye in reflected or transmitted light, projects one or more images that demonstrate various visual effects, such as: orthoparallactic movement; images appear to lie deeper in the spatial plane than the thickness of the polymer film; seem to lie in the spatial plane above the surface of the polymer film; vibrate between the spatial plane deeper than the thickness of the polymer film and the spatial plane above the surface of the film, as the film rotates azimuthally; are transformed from one type, shape, size, color (or a combination of these properties) into another type, shape, size or color; seem to have realistic three-dimensionality. The films in this security element are very resistant to tampering due to their complex multilayer structure and their elements with a high aspect ratio. Another use of microlenses allows the formation of the so-called vario-stereo effects. This is achieved by using linear (lenticular) celindric micro-raster lens structures. In this case, printed or embossed images are formed at a distance of the order of three focal lengths from the plane of the lenticular raster and are not a lattice of microimages, as in the above case, but are formed by specially combining several printed or embossed images (ordinary, non-micro raster lattice images) . Each image is divided into stripes with a width of the order of the period of the lenticular raster, and through the strip with the given law, the changes in the symmetry in the stripes are combined into one single image. When observing such a complex printed image through a lenticular lens raster, various images will be visible at different angles, which forms vario- or stero-effects, including the formation of motion effects observed images. In these systems, optical moire magnification will not be observed.

One of the main disadvantages of microlenses is the location of the lenses on the outer surface of the protective element (they cannot be covered with any protective layer, otherwise the necessary optical effects will be lost). This leads, firstly, to fast and uncontrolled wear (abrasion) of the raster, and, secondly, to the possible appearance of transparent layers of liquid, fat, etc. on the surface of the raster. The quality of the observed variable images deteriorates sharply, or the images completely disappear.

Known methods for creating floating images by forming on the surface or in the volume of the protective elements of the system of the so-called diffractive-refractive relief structures (RU 21 11550 C1, 05.20.1998). In a transparent layer on the surface or in the volume of the protective element, a relief structure is created in the form of systems of grooves (grooves) with the configuration and shape calculated according to a special program. Such systems form a complex combination of Fresnel flat lenses that forming "floating" above or below the surface of the protective element of the changing image. Such images can be observed both in transmitted and reflected light. The disadvantage of such structures is the low brightness and contrast of the observed images with small sizes of protective elements.

Protective elements are also known that use holographic methods for creating changing images of observables when changing the direction of observation and lighting of the protective element (RU 2345900 C2, 02/10/2009). In these elements, several holographic images are formed on the surface or in the volume of the security element using various reference optical frequencies (gratings). However, with the small size of security elements (which is typical for special printing products, such as securities, security threads in banknotes, excise and special stamps, etc.), the contrast and brightness of the observed images deteriorate, the movement of images becomes fuzzy and difficult to distinguish. Observation of images is complicated by their "rainbow" character, arising from high spatial frequencies gratings and diffraction of incident non-monochromatic light on them. It is necessary to apply special measures to increase the contrast, brightness, clarity of the observed images and provide conditions for more reliable fixation of their changes (movements).

SUMMARY OF THE INVENTION The problem solved by the invention and the technical result is to increase the security of products by creating a new optical effect that increases the recognition of the protected object, based on the observation of mutual movements of images when changing the viewing angle.

The technical result is achieved due to the group of inventions, namely due to the fact that a multilayer protective element containing a flexible carrier layer with optically variable structures containing two or more groups of repeating images that move and / or change with a change in the viewing angle is characterized by that optically variable structures are formed in such a way that when changing the viewing angle, different groups of images move relative to each other.

In addition, the multilayer security element is also characterized by the fact that the movement of images belonging to different groups occurs parallel to the plane of change in the viewing angle, so that the images approach or are removed relative to the observer, the movement of images related to different groups occurs perpendicular to the plane of change viewing angle, so that the images move to the right or left of the observer, the movement of images belonging to different groups occurs in different axial directions In relation to the plane of change in the viewing angle or the movement of images belonging to different groups, it is combined with a smooth change in the geometric parameters of the images, for example, the angles of inclination to the longitudinal axis of the protective element or their linear dimensions.

The multilayer security element may be in the form of a strip, or a local thin-film element, a security thread, or a thin-layer film coating structure. 00732

9

Optically, variability is achieved by introducing microlens raster structures, diffraction-refractive structures, or holographic structures into the protective elements.

The technical result is also achieved by the fact that a document protected from forgery, such as a check, a stock, a banknote, an excise stamp, a special federal stamp, a passport, an identification card and other similar products, includes at least one security element described above .

In a particular case, a document protected from forgery is characterized in that the security element is made in the form of a strip or a local thin-film element placed on the surface of the document to be protected or the security element is made in the form of a thin-layer structure covering the document or the security element is made in the form of a security thread inserted into protected document.

The essence of the invention lies in the fact that the protective element containing a flexible carrier layer with optically variable structures containing two or more groups of repeating images that move and / or change when the viewing angle changes, and according to the invention, optically variable structures are formed in such a way that when changing the viewing angle, different groups of images that are closely spaced to each other at a distance of the order of the size of the visible images move relative to each other.

In special cases, as already mentioned, the movement of images belonging to different groups occurs parallel to the plane of change of the viewing angle, so that the images approach or are removed relative to the observer, or the movement of images belonging to different groups occurs perpendicular to the plane of change of the viewing angle , so that the images move to the right or left of the observer, or the movement of images belonging to different groups occurs in different axial directions with respect to -plane variation of the angle of observation or images belonging to different groups, combined with a smooth change of geometric parameters of images, for example, angles of inclination to the longitudinal axis of the protective element or their linear dimensions.

Optically variable structures contain microlens raster structures, diffraction-refractive structures, or holographic structures.

A document protected from forgery, such as a check, a stock, a banknote, an excise stamp, a special federal stamp, a passport, an identification card and other similar products, contains the security element described above.

The security element may be in the form of a strip, or a local thin-film element placed on the surface of the document to be protected, or a thin-layer film structure covering the document to be protected, or a security thread inserted into the document to be protected.

Brief Description of the Drawings

In FIG. 1 presents options for changing images formed by holographic threads at different viewing angles, that is, The process of the change (movement) of the Si and S ₂ symbols described above is illustrated.

In FIG. Figure 2 shows photographs of holographic images observed at different angles formed on a real security element made in the form of a holographic thread. Here, as the symbols Sj and S ₂ , the digits "100" were selected located at a certain distance (1-2 mm) from each other along the thread and changing their visible location and orientation depending on the viewing angle.

BEST MODE FOR CARRYING OUT THE INVENTION Example 1.

Using the dot matrikx digital technology or analog holography methods, a rainbow holographic relief is created on the surface of the holographic foil, which, when viewed visually, forms, at a certain viewing angle ao, an image of two Si and S ₂ symbols located at some IQ distance from each other . When changing the observation angle ao by some angle Δα the observed image is changed so that the distance between the characters increases by ΔΙ. If the viewing angle is increased by another Δα, the distance between the symbols will increase to Ιο + 2ΔΙ. With a further increase in the observation angle by ηΔα, a corresponding increase in the distance between the observed symbols by ηΔΙ occurs. Starting from a certain value n = M, the sign ΔΙ can be changed, and the distance between the characters will begin to decrease. With sufficiently small values of Δα and ΔΙ and a smooth change in the viewing angle, the movement of the symbols Si and S ₂ will be observed, first in the direction from each other, and then towards each other. Moreover, due to physiological characteristics of vision, recognition of the movement of characters is facilitated. During the movement of characters, they can additionally change their shape, size and orientation (as illustrated in the second and third lines of symbolic images in figure 1), which further increases the recognition of the movement of characters. Example 2

Similarly to the considered implementation of the optical variable structure based on the rainbow holographic element in Example 1, it is possible to form floating images with the multidirectional movement of their fragments in diffraction-refractive structures in the form of a combination of Fresnel lenses combined with each other or in the form of a thin-film nano-prismatic system of diffractive optical elements. In the first case, the formation of floating images is carried out by structures obtained by embossing with master matrices made by precision engraving of concentric annular grooves (grooves) of a given profile, forming a system of Fresnel lenses intersecting with each other. The engraving resolution (characteristic dimensions of the groove profile) is of the order of 1-10 microns. In the second case, the structure forming floating images is created using electronic, ion, or laser nanolithographs with a resolution of the order of 10-100 nm. The structure is nano-sized tubercles and pits distributed according to a given law. Example 3

Floating images with multidirectional movement of groups of individual fragments can also be organized in optical elements based on structures with micro-lens rasters and systems of micro-image gratings. In this case, the nature of the observed motion of enlarged moire images is determined by the parameters and orientation of the microimage lattices and micro lenses. In the simplest case, certain local portions of the microimage raster with sizes of the order of 10-100 spatial periods (as a rule, the characteristic size of the spatial period of the lattices is 10-100 microns) are left free of microimages. Upon observation, these areas will appear to be floating above a plane with moving enlarged images of microimages, i.e. the apparent multidirectional movement of such local areas with respect to moving remote background images will be formed. Industrial applicability

This invention allows to simplify the process of identifying falsified and fake documents, as it allows to increase the security of products by creating a new optical effect that increases the recognition of the protected object, based on the observation of mutual movements of images when changing the viewing angle.

Claims

Claim

1. A multilayer security element containing a flexible carrier layer with optically variable structures containing two or more groups of repeating images that move and / or change when the viewing angle changes, characterized in that the optically variable structures are formed in such a way that when changing the viewing angle different groups of images move relative to each other.

2. The multilayer security element according to claim 1, characterized in that the movement of images belonging to different groups occurs parallel to the plane of change of the viewing angle, so that the images are approached or deleted relative to the observer.

3. The multilayer security element according to claim 1, characterized in that the movement of images belonging to different groups occurs perpendicular to the plane of change of the viewing angle, so that the images move to the right or left of the observer.

4. The multilayer security element according to claim 1, characterized in that the movement of images belonging to different groups occurs in different axial directions with respect to the plane of change of the viewing angle.

5. The multilayer security element according to claim 1, characterized in that the movement of images belonging to different groups is combined with a smooth change in the geometric parameters of the images, for example, angles of inclination to the longitudinal axis of the security element or their linear dimensions.

6. The multilayer security element according to any one of paragraphs 1-5, characterized in that it is made in the form of a strip, or a local thin-film element, or a security thread, or a thin-layer film coating structure.

7. The multilayer security element according to any one of paragraphs 1-5, characterized in that the optically variable structures contain microlens raster structures.

8. The multilayer security element according to any one of paragraphs 1-5, characterized in that optically variable structures contain diffraction-refractive structures.

9. The multilayer security element according to any one of paragraphs 1-5, characterized in that the optically variable structures contain holographic structures.

10. A document protected from forgery, such as a check, a stock, a banknote, an excise stamp, a special federal stamp, a passport, an identification card and other similar products, including at least one security element described in any of clauses 1-9.

1 1. A document protected from forgery according to claim 10, characterized in that the security element is made in the form of a strip or a local thin-film element placed on the surface of the document to be protected.

12. A document protected from forgery according to claim 10, characterized in that the security element is made in the form of a thin-layer structure covering the document to be protected.

13. A document protected from forgery according to claim 10, characterized in that the security element is made in the form of a security thread inserted into the document to be protected.