EP2723945B1 - Security thread - Google Patents

Description

The present invention relates to security threads and valuable or security documents incorporating such threads.

Security threads are security features that are often used in banknotes to help make counterfeits more difficult and to authenticate them.

Numerous son have been described which aim both to provide security difficult to reproduce and produce a visually appealing appearance.

EP 1 819 525 B1 discloses a security element comprising platelet-shaped pigments which can be oriented under the effect of a magnetic field so as to make it possible to observe, for a direction of observation substantially parallel to the orientation of the pigments, a subtle impression. core. The security element has two zones whose pigments are oriented differently so that the appearance / disappearance of the underlying patterns can be observed when the direction of observation changes. The security element may be in the form of a wire.

The invention aims to further improve the security son, and it succeeds, according to a first aspect, with a security thread to be incorporated into a security document, comprising at least two areas respectively of share and another of a dividing line extending longitudinally along the wire, a first optically variable security element in the first zone and a second optically variable security element in the second zone, the first and second elements being distant one and the other of the separation line and arranged so that for a first direction of observation the two elements have different aspects from each other and for a second direction of observation, different from the first, the two elements have, on the one hand, each one changed in aspect with respect to their aspect when observed according to the first direction of observation, and on the other hand have different from each other.

An interesting visual effect has been obtained by putting the first and second elements on the wire close to one another, the same optical characteristic, for example the same color, passing from one zone to another when the direction of observation changes. Because of their spacing, the two elements are visually separated by a zone neutral, which can be used to achieve additional safety and / or further improve the appearance of the wire.

The invention reduces the risk of superposition of the first and second security elements, which would have the effect of impairing the obtaining of the desired visual effects in the overlap zone. The neutral zone between the two elements allows easier production, because it allows for example to overcome identification problems when the security elements are made by printing.

The aforementioned separation line may be median, and the first and second zones may be symmetrical to each other with respect to this line.

The presence of a gap between the first and second elements, in addition to facilitating the manufacture of the wire, further allows, if desired, to have a third security element on the wire.

This third element may extend longitudinally and be located at least partially visually between the first and second optically variable elements. The third element makes it possible to raise the security level of the security thread in addition to serving as tolerance zone for the realization of the two aforementioned elements.

The third element may have a first, second or third level security feature.

"First-level security" means security that is detectable by the eye, in daylight, or in artificial light, without the use of a particular device.

Other types of additional security elements are detectable only with a relatively simple apparatus, such as a lamp emitting in the ultraviolet (UV) or infrared (IR). These security elements may be visible to the naked eye or not, being for example luminescent under a lighting of a Wood lamp emitting in a wavelength of 365 nm. These security elements are said to be second level.

Other types of security elements require for their detection a more sophisticated detection device. These security elements are for example capable of generating a specific signal when they are subjected, simultaneously or not, to one or more external excitation sources. The automatic detection of the signal makes it possible to authenticate, if necessary, the element. These security elements comprise, for example, tracers in the form of active materials, particles or fibers, capable of generating a specific signal when these tracers are subjected to optronic, electrical, magnetic or electromagnetic excitation. These security elements are said to be third level.

• une démétallisation, notamment une démétallisation qui représente un même motif qu'un motif imprimé entre les première et deuxième zones optiquement variables ou au niveau de celles-ci, de sorte à constituer un élément de comparaison,
• une bande magnétique, créant une sécurité de troisième niveau, ou
• un élément coloré ou à effet goniochromatique, métallique, holographique, entre autres possibilités.

The third security element may comprise or be constituted by:

• a demetallization, especially a demetallization which represents the same pattern as a pattern printed between the first and second optically variable zones or at the level thereof, so as to constitute a comparison element,
• a magnetic tape, creating a third level security, or
• a colored or goniochromatic element, metallic, holographic, among other possibilities.

The security thread preferably has a width ranging from 2 to 10 mm, more preferably from 4 to 6 mm.

The neutral zone has a width of preferably 0.2 to 1.5 mm, more preferably 0.4 to 0.8 mm.

The third element may be superimposed on or at least partially cover one of the first and second optically variable elements, when the security thread is viewed from the front. The third security element may be wider than the interval between the first and second security elements.

The third element can be superimposed on or at least partially cover both the first and second security elements.

The third element may extend in a continuous or discontinuous strip.

The third member may be disposed on one side of a wire strand carrier and the first and second members may be disposed on the opposite side of the carrier.

The support may be made of a thermoplastic material, preferably a transparent thermoplastic material, more preferably polyester or PET.

The first and second security elements may comprise the same pigment, preferably reflecting, which is deposited differently on the first and second zones, in particular with a different orientation. The pigment can be magnetic and platelet-shaped, just as in the patent EP 1 819 525 B1 . The pigment particles may coat underlying prints or pattern elements made otherwise than by printing. As the pigment particles are oriented, there is a first angle of observation according to which the particles reflect, in this case the printed pattern or the color below is not visible, and a second angle of observation according to which the particles are not oriented so as to be able to reflect, and in this case the pattern or the color arranged below is visible.

The first and second optically variable elements may also each comprise a lenticular array. The lenses of the lenticular network make it possible to observe or not, depending on the angle of observation, at least one underlying pattern element.

In a particular example of implementation of the invention, the security thread comprises a variable opacity element superimposed at least partially on the first and second optically variable elements, defining first and second zones of lesser opacity superimposed on each other. partially respectively with the first and second optically variable elements. The variable opacity element may also be superimposed on the third security element and may define a third zone of lesser opacity superimposed at least partially on the third security element, through which the third security element may be visible. The variable opacity element may define a surrounding area of greater opacity, extending around the first, second, and third zones.

By "opacity", we consider the attenuation of the intensity of an illuminant that passes through a material. The opacity of a material can vary between zero opacity (or transparency) and total opacity, where the illuminant is not transmitted.

By "illuminant" is meant light visible to the human eye, for example daylighting illuminant D65, defined by CIE Lab 1976, infrared (IR) or ultraviolet (UV) radiation.

By "variable opacity" is considered an element that has in different areas different absorption properties of a predefined illuminant, including visible light.

In an exemplary implementation of the invention, for an observation in visible light, the security thread comprises a variable opacity element obtained by metallization / demetallization. This element has a surrounding area of greater opacity corresponding to a metal layer and areas of less opacity corresponding to openings resulting from the demetallization. In visible light, the metal layer appears totally opaque and the openings are transparent.

In another exemplary embodiment of the invention, for an observation under a UV or IR illuminant, the variable opacity element comprises an impression, on the zone of greater opacity, with an ink comprising a transparent pigment when 'observed in visible but opaque light when illuminated under UV or IR.

When observed in reflection in a first direction of observation through the first (respectively the second) zone of least opacity, the first (respectively second) optically variable element may appear transparent (respectively reflective). When observed in a second direction of observation different from the first through the first (respectively the second) zone of least opacity, it is the opposite that can occur, the first element (respectively the second) optically variable appearing reflective (respectively transparent).

The first and second optically variable elements may comprise a luminescent compound, for example a fluorescent compound, this compound being present in one or more units. Thus, the two steps of observation of the security thread at different angles show in reflection one or more colors produced by luminescence, preferably different colors, through the zones of less opacity.

The zones of the first and second optically variable elements observed respectively through the first and second zones of least opacity may take the form of a letter and / or a text and / or a drawing and / or a pattern.

Preferably, the variable opacity element extends longitudinally along a support of the security thread, and may be in the form of a band. The zone of greater opacity can define the opposite edges of this band, which can be continuous, the areas of less opacity extending behind these edges.

Preferably, the width of the variable opacity element is between 1 to 10 mm, more preferably from 4 to 8 mm.

The variable opacity element may be totally or partially superimposed on the first and second optically variable elements.

The area of greater opacity of the variable opacity element may be continuous. Alternatively, it may be discontinuous. For example, it is separated into at least two distinct parts by a frame or is pixelated, so for example to form a pattern in three dimensions. In case the variable opacity structure is discontinuous, the area of greater opacity may be discontinuous at the microscopic scale, while appearing substantially continuous to the naked eye. When formed by metallization / demetallization, its opacity is then intermediate between that of a full demetallized zone and that of a fully metallized zone. In one example, the area of greater opacity is pixelated (including halftone), the areas of less opacity being devoid of pixels or frame. The area of greater opacity can form a three-dimensional image when observed in transmitted light.
The variable opacity element can totally or partially cover the first and second optically variable elements. The area covered by the first and second areas of least opacity may be less extensive than the area covered by the surrounding area of greater opacity. Preferably, the area covered by the first and second areas of least opacity is 1.5 times, preferably twice, more preferably 3 times, even 5 times, or even more than 10 times, less than the area covered by the surrounding area of greater opacity.

It is thus possible to define first and second areas of less opacity in the form of letters, a text, a pattern, a drawing of small dimensions compared to those of the security thread. In this way, it is particularly possible to focus on these first and second areas of least opacity the attention of the observer who authenticates a document comprising such a security thread.

Alternatively, the area covered by the first and second areas of least opacity may be larger than the area covered by the surrounding area of greater opacity.

For example, a particular optical characteristic, such as a bright reflection effect, may change from the first zone of least opacity to the second zone of least opacity with a change of the direction of observation, an optical characteristic of the zone of greater opacity (including its color) being for example conserved. A variation of the visual appearance of the first and second optically variable elements, through the first and second areas of least opacity, is obtained by selecting the suitably variable opacity element. Thus, it is possible to define first and second areas of least opacity in the form of a letter, a text, a pattern or a drawing so that they present alone in the security thread an aspect optically variable.

In a particular case of implementation of the invention, the superposition of the zone of greater opacity with the first and second optically variable elements respectively defines fourth and fifth optically variable zones, so that when observed in a first direction observation, respectively in a second direction different from the first, the fourth optically variable zone, respectively the fifth optically variable zone, has a different visual appearance of the fifth zone, respectively the fourth zone, and in particular appears clearer, respectively darker.

The variable opacity element may have an opacity depending on the type of illuminant used for the observation.

• une métallisation/démétallisation, notamment avec une démétallisation qui représente une ou plusieurs lettres, un dessin, un motif ; dans ce cas, les zones de moindre opacité correspondent aux zones démétallisées et les zones de plus grande opacité correspondent aux zones métallisées ; le ou les motifs formés par les zones démétallisées peuvent se retrouver ailleurs sur le document qui intègre le fil de sécurité ; il s'agit par exemple de la valeur de la coupure, de la devise ou du nom du pays ou de la banque émettrice ; le métal peut être choisi par exemple parmi l'argent, l'aluminium, le nickel, le cobalt, l'étain, l'or, le cuivre, et parmi les alliages de métaux, notamment le laiton ou le bronze ; le métal peut être remplacé par tout matériau diélectrique ; des éléments diélectriques à effet miroir ou interférentiel constitués d'une alternance de couches de haut et de bas indice, par exemple respectivement du dioxyde d'hafnium et de la silice, notamment obtenus par gravure ionique , peuvent être utilisés,
• un élément en un matériau coloré ou à effet goniochromatique, métallique, holographique, entre autres possibilités, afin de faire varier l'opacité de l'élément sur des zones prédéfinies,
• un élément en un matériau dont l'opacité peut varier par exemple par application sélective sur des zones définies d'un traitement thermique ou d'un traitement laser,
• un élément obtenu par embossage, notamment à chaud, d'un matériau aux propriétés initiales d'absorption de la lumière homogènes, de sorte que la variation d'opacité résulte de la variation d'épaisseur causée par l'embossage,
• une impression avec différentes encres, colorées ou non, visibles à l'oeil nu ou non, par exemple des encres visibles uniquement sous lumière ultraviolette ou infrarouge, opaques en lumière visible, fluorescentes, phosphorescentes, thermochromiques, photochromiques, translucides et/ou transparentes,
• un élément comportant une image pixellisée, incluant tramée, produisant un effet visuel de profondeur quand observée en lumière transmise, comme par exemple celle décrite dans EP-A-1674286 .

The variable opacity element can comprise, or even consist of:

• a metallization / demetallization, in particular with a demetallization which represents one or more letters, a drawing, a pattern; in this case, the zones of less opacity correspond to the demetallized zones and the zones of greater opacity correspond to the metallized zones; the pattern (s) formed by the demetallized zones can be found elsewhere on the document that integrates the security thread; for example, the value of the denomination, the currency or the name of the country or issuing bank; the metal may be chosen for example from silver, aluminum, nickel, cobalt, tin, gold, copper, and from metal alloys, especially brass or bronze; the metal can be replaced by any dielectric material; mirror or interference-effect dielectric elements consisting of an alternation of high and low index layers, for example hafnium dioxide and silica, for example obtained by ion etching, may be used,
• an element made of a colored or goniochromatic material, metallic, holographic, among other possibilities, in order to vary the opacity of the element on predefined zones,
• an element made of a material whose opacity can vary for example by selective application to defined zones of a heat treatment or a laser treatment,
• an element obtained by embossing, in particular when hot, a material with homogeneous initial properties of absorption of light, so that the variation in opacity results from the thickness variation caused by the embossing,
• a printing with different inks, colored or not, visible to the naked eye or not, for example inks visible only under ultraviolet or infrared light, opaque in visible light, fluorescent, phosphorescent, thermochromic, photochromic, translucent and / or transparent,
• an element comprising a rasterized image, including a raster, producing a visual effect of depth when observed in transmitted light, such as that described in EP-A-1674286 .

The image can represent a portrait, an animal, a landscape, a symbol, notably alphanumeric, a line, a guilloche. It may comprise a set of points appearing more or less distant, when observed in transmitted light. These points may be of various shapes and / or sizes, possibly with specific frequency modulation. For example, the dots may be square, round, diamond, or elongated, such as a line, and may form a frame. The points may line up in inclined lines at specific angles, with specific frequency modulation. Points can define positive and / or negative images. The rasterized image may include observable points under ultraviolet (UV) and / or infrared (IR) radiation. These points may contain pigments visible under UV or IR radiation and invisible in daylight. The rasterized image may contain dots that, at least partially, represent coded data, particularly in matrix form. For example, the code may be related to the spatial position of the points and / or to opacities and / or to sizes and / or shapes and / or thicknesses and / or colors of said points. The pixellated image is made of at least one material selected from metals, alloys, varnishes and metallic inks, varnishes and metallic-looking lacquers. The points are preferentially applied to the support of the security thread and / or to the optically variable elements by printing and / or by the techniques of metallization and / or partial demetallization. The rasterized image can be made in several layers, applied on the security wire support, and / or on the first and second optically variable elements, and preferably have different optical densities. Thus, these different layers at different optical densities produce a pattern, symbols, letters, lines that define a visual effect of depth when observed in transmitted light. Other layers with optical and / or magnetic and / or electrical properties described EP-A-1674286 may be present.

By "visual depth effect" is considered a visual effect by which different elements defining a plane image, including pixels of the image, appear more or less distant to the observer due to a perspective effect. For example, a mark or image consisting of a frame or dots appears as a mark or a three-dimensional image when viewed in transmitted light.

Preferably, the third zone mentioned above, of less opacity, corresponds to an aperture in the element of variable opacity. It can also be defined by a region of a transparent material of the variable opacity element through which an illuminant, including visible light, is transmitted.

The third element can also be superimposed on or covered, especially entirely, by the zone of greater opacity. In a particular embodiment, it is invisible to the observer under visible light and is detected under another illuminant, for example ultraviolet (UV) or infrared (IR) radiation.

The third member may be disposed on one side of the holder and the first and second members may be disposed on the opposite side of the holder.

In an exemplary implementation of the invention where the security thread comprises a variable opacity element and is disposed in a security document, the color difference ΔE in the CIE Lab color space between the region of the document which extends around the security thread and the variable opacity element is less than 5, better than 2. Thus, the color of the variable opacity element is close to that of the document around the security thread. In this case, according to at least one observation angle, the security thread can not be visually distinguished from the region of the document adjacent to the security thread. Under another angle of observation, a pattern defined by the first and / or second zone of less opacity for example becomes reflective while the color of the zone of greater opacity and of the document around the variable opacity element is substantially unchanged.

The pattern (s) defined by the areas of least opacity of the security thread can be found elsewhere on the security document and thus establish a link between the security document and the security thread. Preferably, in the case where the security document is a bank note, the reason represents for example the currency, the name of the bank or the value of the cutoff. The first optically variable element can be made on a film in the form of spaced apart parallel strips and the second optically variable member to be in the form of spaced parallel strips interwoven with the strips formed by the first member, with a spacing between the strips of the first member and the strips of the first member. second element, the film being cut at half-width of the strips of the first element and strips of the second element to form a plurality of security son.

The strips can be made for example by printing, for example in successive passes on the film. The film can be returned between the passes, for example by rotating about an axis perpendicular to the surface of the film, which is a simple and effective way to orient the pigment particles differently, especially in the case where the first and second security elements are orientable reflective particles.

The subject of the invention is also a security document incorporating a security thread according to the invention, as defined above, the thread extending from one edge of the document to an opposite edge.

• un support,
• un premier élément optiquement variable porté par le support,
• un deuxième élément optiquement variable porté par le support, les premier et deuxième éléments ayant des première et deuxième régions, non superposées sur le support,
• un élément d'opacité variable recouvrant au moins partiellement les première et deuxième régions, définissant des première et deuxième zones de moindre opacité se superposant au moins partiellement respectivement avec les première et deuxième régions et une zone environnante de plus grande opacité, le fil de sécurité étant disposé sur le substrat de telle sorte que les première et deuxième régions soient visibles à travers l'élément d'opacité variable, les premier et deuxième éléments étant agencés de telle sorte que pour une première direction d'observation, les premier et deuxième éléments aient lorsqu'observés simultanément à travers respectivement les première et deuxième zones de moindre opacité des aspects différents l'un de l'autre et, pour une deuxième direction d'observation différente de la première, les premier et deuxième éléments aient lorsqu'observés simultanément à travers respectivement les première et deuxième zones de moindre opacité, d'une part changé d'aspect par rapport à leur aspect lorsqu'observés selon la première direction d'observation, et d'autre part aient des aspects différents l'un de l'autre.

The invention also relates to a security document, comprising a substrate and a security thread comprising:

• a support,
• a first optically variable element carried by the support,
• a second optically variable element carried by the support, the first and second elements having first and second regions, not superimposed on the support,
• a variable opacity element at least partially covering the first and second regions, defining first and second areas of least opacity superimposed at least partially respectively with the first and second regions and a surrounding area of greater opacity, the security thread being disposed on the substrate so that the first and second regions are visible through the variable opacity element, the first and second elements being arranged such that for a first viewing direction, the first and second elements when observed simultaneously through respectively the first and second areas of least opacity different aspects of each other and, for a second direction of observation different from the first, the first and second elements have when observed simultaneously through respectively the first and second areas of least opacity, on the one hand changed appearance with respect to their appearance when observed in the first direction of observation, and secondly have aspects different from each other.

By "security document", synonymous with "secure document" means a valuable document, for example a means of payment, such as a bank note, a check or a restaurant ticket, a lottery ticket, a title transportation or a ticket giving access to a cultural or sporting event and / or a document for the identification of persons, such as an identity card, a visa, a passport or a driving license.

There is also described a method for authenticating or identifying a document comprising a security thread according to the invention, in which the appearance change of the first and second optically variable elements is observed by modifying the observation direction some thread.

In particular, it can be ascertained whether, when the angle of observation changes, the appearance of one zone of the wire disappears and is found on another zone.

In an exemplary implementation of the method, a security feature of the third security element is detected, this being then present.

There is also described a method of manufacturing a security thread according to the invention, which may comprise a step of forming an element of variable opacity when it is present in the security thread.

More particularly, this process may comprise a step of preparing a variable opacity element, preferably by demetallization, in particular by etching, of a layer of metal covering the support and / or the first and second optically variable elements, and covered by the printing of a varnish, the latter protecting against the chemical attack. In a variant, a solvent-soluble primer is applied to the support and / or to the first and second optically variable elements according to the negative of the pattern to be produced before the metallization, and then the latter is carried out. The chemical attack solubilizes the primer and the metal leaves the support at the replacements where the soluble primer is present. The metal layer is preferably deposited by vacuum metallization.

The manufacturing method may also include a step of depositing a security thread according to the invention on the security document. When it has an element of variable opacity, the security thread is disposed on a substrate of the security document so that the first and second optically variable elements are visible through the variable opacity element.

• la figure 1 représente, de face, un exemple de document de valeur selon l'invention,
• la figure 2 représente isolément, en coupe transversale, le fil de sécurité,
• les figures 3 et 4 représentent des exemples de réalisation des zones optiquement variables,
• les figures 5 et 6 illustrent le changement d'aspect du fil lors d'une modification de la direction d'observation,
• la figure 7 est une vue analogue à la figure 2 d'une variante de réalisation du fil,
• les figures 8 et 9 illustrent une variante de réalisation des zones optiquement variables,
• les figures 10 et 11 illustrent le changement d'aspect des zones optiquement variables avec la modification de la direction d'observation,
• les figures 12 et 13 illustrent la réalisation des zones optiquement variables par impression,
• les figures 14, 15, 16 et 17 représentent de manière schématique et partielle, en coupe transversale, des fils de sécurité comportant chacun un élément d'opacité variable, suivant différents modes de réalisation,
• les figures 18 et 19 illustrent le changement d'aspect des zones optiquement variables auxquelles se superposent un élément d'opacité variable,
• les figures 20, 21 et 22 illustrent une variante de réalisation du fil de sécurité, dans lequel l'élément d'opacité variable comporte une image pixellisée,
• la figure 23 illustre une variante de réalisation du fil de sécurité comportant une trame,
• les figures 24 et 25 représentent, en coupe transversale, une variante de réalisation des zones optiquement variables,
• les figures 26 et 27 illustrent le changement d'aspect des zones optiquement variables des variantes des figures 24 et 25 avec la modification de la direction d'observation,
• la figure 28 représente en vue de face un document de sécurité dans un exemple de mise en oeuvre de l'invention,
• la figure 29 représente à échelle agrandie le détail I du document de sécurité de la figure 28,
• la figure 30 est une coupe transversale selon XXVIII-XXVIII de la figure 28, illustrant le positionnement en fenêtre du fil de sécurité dans le document de sécurité, et
• la figure 31 illustre une variante de positionnement en surface du fil de sécurité.

The invention will be better understood on reading the following detailed description, non-limiting examples of implementation thereof, and on examining the appended drawing, in which:

• the figure 1 represents, from the front, an example of a document of value according to the invention,
• the figure 2 represents in isolation, in cross-section, the safety wire,
• the Figures 3 and 4 represent exemplary embodiments of the optically variable zones,
• the Figures 5 and 6 illustrate the change of appearance of the wire during a modification of the direction of observation,
• the figure 7 is a view similar to the figure 2 an embodiment variant of the wire,
• the Figures 8 and 9 illustrate an alternative embodiment of the optically variable zones,
• the Figures 10 and 11 illustrate the change of appearance of the optically variable zones with the modification of the direction of observation,
• the Figures 12 and 13 illustrate the realization of the optically variable zones by printing,
• the Figures 14, 15, 16 and 17 show schematically and partially, in cross-section, security threads each having a variable opacity element, according to different embodiments,
• the Figures 18 and 19 illustrate the change in appearance of the optically variable zones to which a variable opacity element is superimposed,
• the Figures 20, 21 and 22 illustrate an alternative embodiment of the security thread, wherein the variable opacity element comprises a pixelated image,
• the figure 23 illustrates an alternative embodiment of the security thread comprising a frame,
• the Figures 24 and 25 represent, in cross-section, an alternative embodiment of the optically variable zones,
• the Figures 26 and 27 illustrate the change in appearance of the optically variable zones of the variants of Figures 24 and 25 with the modification of the direction of observation,
• the figure 28 represents a front view of a security document in an exemplary implementation of the invention,
• the figure 29 represents on a larger scale detail I of the security document of the figure 28 ,
• the figure 30 is a cross section according to XXVIII-XXVIII of the figure 28 , illustrating the window positioning of the security thread in the security document, and
• the figure 31 illustrates an alternative positioning on the surface of the security thread.

In the appended drawing, the actual proportions of the constituent elements of the security thread, and the constituent elements of the security document are not always respected for the sake of clarity of the drawing. On the other hand, some elements are not represented in contact with each other for the sake of clarity, whereas they are in practice.

We have shown figure 1 a security document 1 according to the invention, for example a banknote, which comprises a substrate 2 and a security thread 3 according to the invention. The latter extends between two opposite edges 4 and 5 of document 1.

The security thread 3 may be incorporated at least partially in mass in the substrate 2 of the security document, and only part of the thread 3 appears visible, for example through one or more windows 6 formed in the substrate. An example of incorporation into windows is described in the document EP 59056 .

Preferably, the substrate 2 of the security document incorporating the security thread 3 consists of natural fibrous materials, for example cellulose and / or cotton, and / or synthetic fibers. The substrate 2 can also be made from plastic materials, such as a Polyart ^™ film sold by the company ARJOBEX Ltd.

In isolation figure 2 the security thread 3. This comprises a support 10, preferably a transparent thermoplastic material, for example polyester or PET.

The support 10 is of flattened cross section, in particular rectangular as illustrated. The thickness of the support 10 is for example between 8 and 30 microns, preferably between 12 and 23 microns.

Impressions 11 are made on a face 12 of the support 10, in two zones 13 and 14 spaced apart from each other and between which there is an intermediate zone 15.

The impressions 11 are covered on the side of the opposite face 19 of the support 10 by respective layers 16 and 17 of platelet reflective and magnetic pigments, each deposited in the form of a strip extending along the wire.

The pigments of layers 16 and 17 are oriented differently, as shown in FIGS. Figures 3 and 4 . Thus, for an observation direction O parallel to the orientation direction of the platelets of the pigment, the underlying impression 11 is visible and for a different viewing direction D, the pigment is reflective and the print 11 under is not visible. Optically variable zones 31 and 32 separated by the intermediate zone 15 are thus obtained and, for example, the change of appearance illustrated in FIGS. Figures 5 and 6 when the direction of observation is changed.

On the figure 5 , for one direction of observation, one of the zones appears dark and the other clear. On the figure 6 , it's the opposite.

The prints 11 can be directly made on the support, as is the case on the figure 2 or alternatively on an independent transparent layer, for example PET, laminated by means of an adhesive on the rest of the security thread. Thus, the wire may comprise a multilayer support.

The width L of the wire 3 is preferably between 2 and 10 mm, and that the intermediate zone 15 between 0.5 and 1.5 mm.

A third security element 20 is deposited between the impressions 11, under the intermediate zone 15, on the face 12 of the support 10, as illustrated in FIG. figure 2 . This third security element 20 may be visible on the side of the face 19, thanks to the non-opaque nature of the support 10.

• une couleur invariable, différente des impressions 11 réalisées dans les zones 13 et 14, ou identique à celles-ci,
• une bande magnétique, qui peut contenir un code magnétique,
• un texte ou autres motifs formés par démétallisation,
• une structure holographique,
• un pigment goniochromatique ou tout autre structure à effet de changement de couleur, ou
• un pigment thermochromique.

The third security element 20 may consist of:

• an invariable color, different from the impressions 11 made in the zones 13 and 14, or identical thereto,
• a magnetic tape, which may contain a magnetic code,
• text or other motifs formed by demetallization,
• a holographic structure,
• a goniochromatic pigment or other color-changing structure, or
• a thermochromic pigment.

The wire 3 can be made in such a way that the change in appearance of the zones 31 and 32 takes place when the observation direction rotates about an axis parallel to or coincident with the median longitudinal line X of the wire 3, or alternatively around an axis perpendicular to said longitudinal line. The angular difference between the two directions of observation is for example at least 5 °, better 15 °. The angular difference is for example between 5 and 50 °, better between 15 and 20 °.

The pigments are oriented according to the axis around which the observation direction must turn to observe the desired change of appearance. For example, the pigments are oriented, the X axis being vertical, respectively to the left and to the right, to obtain a change of appearance when turning from left to right or vice versa.

On the figure 7 there is shown an alternative embodiment in which the layers 16 and 17 also cover the security element 20 but in which the impressions 11 are spaced apart from the third security element 20, defining intervals 21, for example in the form of characters or bands.

In the example of the figure 2 , the element 20 is wider than the width l of the intermediate zone 15 formed between the layers 16 and 17. In a variant, the situation is different, and the element 20 is for example less wide.

In a variant, the prints 11 are made on the face 19.

On the examples of Figures 14 and 15 , there is shown a security thread as described with reference to the figure 2 whose optically variable elements 16 and 17 are covered with a variable opacity element 60, for example metallization / demetallization or printing. The first 16 and second 17 elements have first A and second B regions, not superimposed on the support 10.

The variable opacity element 60 defines a first C and a second E areas of least opacity which are superimposed respectively on the first 16 and second 17 optically variable elements. The variable opacity element 60 defines a third zone of least opacity F which is superimposed on the third security element 20. A surrounding area of greater opacity G extends around the first, second and third zones.

On the example of the figure 14 , the third zone of least opacity F is obtained using an aperture 61, for example longitudinal, made within the variable opacity element 60. This aperture 61 can separate the variable opacity element 60 in two separate parts.

On the example of the figure 15 , the third security element 20 is visible through the third zone of less opacity F, a region 62 of the variable opacity element material 60 having a lower opacity than its vicinity. Preferably, the region 62 is transparent.

In the example of the figure 16 a second support 101, for example PET, preferably transparent, is used to facilitate the deposition of the variable opacity element and protect the optically variable elements 16 and 17. This support can facilitate the manufacture of the element d variable opacity by a metallization / demetallization process.

In a variant not shown, the third security element 20 is disposed in the gap 15 on the face of the support 10 which carries the two optically variable elements 16 and 17. "

On the figure 17 the variable opacity element 60 and the first 16 and second 17 optically variable elements are located on respective opposite faces of the support 10.

Impressions 11 may optionally be arranged on the face of the support 10 opposite to that where the optically variable elements 16 and 17 are arranged, and may be partially or completely visible when observed through the first and second areas of least opacity C and E, as illustrated on Figures 14 to 16 .

In a particular embodiment of the invention, the zone of greater opacity G is not totally opaque and transmits a portion of the visible light.

As illustrated on the figure 17 the superposition of the region of greater opacity G with the first 16 and second 17 optically variable elements respectively defines fourth M and fifth N optically variable zones.

On a security wire having a variable opacity element 60 as shown in FIGS. Figures 14 to 17 , by modifying the angle of observation, one thus observes for example the change of aspect illustrated with Figures 18 and 19 . In this example, seen from the front, a first set consisting of the fourth optically variable zone M and the first zone C of less opacity and a second set consisting of the fifth optically variable zone N and the second zone D of least opacity are located on either side of the third zone of least opacity F, through which the third security element 20 is visible.

Following a first observation direction O illustrated figure 18 the fourth optically variable zone M appears lighter than the fifth zone N, and the first optically variable element 16, observed through the zone of least opacity C, appears transparent. It may then be possible to observe underlying impressions as appropriate. The second optically variable element 17, observed through the second zone E of less opacity, appears reflective.

On the figure 19 , the opposite effect of that observed on the figure 18 is obtained by varying the angle of observation.

In an exemplary implementation of the invention, the surrounding area of greater opacity G is completely opaque, only the first C and second E areas of less opacity appear visually different in the direction of observation. The fourth M and fifth N optically variable areas have substantially the same appearance, regardless of the angle of observation. The surrounding area of greater opacity G has a visual characteristic, for example a color, uniform and not variable with the viewing angle. In the observation direction O or Q, a reflective aspect of the platelet particles is visible only through one of the first C and second E areas of less opacity.

The security thread 3 can be observed from the front in transmitted light. The security wire is then placed between a light source and the observer. The light emitted by the source passes through the safety wire. In this observation and authentication mode, when observed simultaneously, the patterns defined by the areas of least opacity C and E are partially opaque and have a substantially identical visual appearance. Preferably, for this purpose, the angles of observation of the platelet particles with respect to the normal are substantially the same, in absolute value. The third and fourth zones optically variable M and N may have a substantially identical appearance. They may appear darker than the patterns defined by the areas of least opacity C and E, because the illuminant must cross the G area of greater opacity.

The Figures 20, 21 and 22 show an embodiment where the variable opacity element 60 comprises pixelated images 70 and 71, for example disclosed in FIG. EP-A-1674286 , representing for example the face of a woman and superimposed respectively on the first 16 and second 17 optically variable elements. These images define the area of greater opacity G.

The element 60 of variable opacity comprises first C and second E zones of less opacity corresponding for example to openings 72 and 73, for example located at the level of the eyes of the images 70 and 71. Each of these images advantageously comprises a succession elements, for example points or lines, for example of different colors, arranged in such a way that a visual effect of depth is produced, when observed in transmitted light, the elements of the pixellated image appear more or less distant to the observer. This visual effect is for example related to the size (for example the diameter of the points or the thickness of the lines), the position or the density of the elements of the pixelated image.

When the security thread 3 is observed in reflection in the direction O, the first optically variable element 16 appears transparent through the zone of least opacity C, as illustrated. figure 20 . The superposition of the surrounding area of greater opacity G and the first optically variable element 16 not being completely opaque, the pixelated image 70 can appear visually in depth. In this direction O, the second optically variable element 17 is reflective when observed in reflection. The eyes of image 70 appear reflective. No light can be transmitted through the security wire in the area superimposed on the second element 17. In this area, the image 71 has the appearance of a flat image, and does not appear visually in depth. It also appears darker than the area of greater opacity G superimposed on the first optically variable element 17.

On the figure 21 it is the opposite effect that is produced, according to the observation direction Q, symmetrical with respect to the normal.

On the figure 22 , security thread 3 is observed from the front in transmitted light, in a direction perpendicular to the security thread. In this case, both zones optically variable M and N, as defined for example on the figure 17 , appear visually in depth to the observer.

On the figure 23 the possibility has been illustrated for the surrounding area G to be discontinuous on a microscopic scale, comprising a frame 77 which extends for example from one edge 78 to the other 79 of the variable opacity element and transversely separates the variable opacity element into distinct parts. This frame may appear to be continuous when observed in reflection, the less opaque lines 77a being for example more numerous, narrow and close than illustrated. This frame can be pixelated and appear visually in depth when observed in transmitted light, as in the example of Figures 20 to 22 .

In the above examples, the variable opacity element 60 may be a metallization / demetallization, for example obtained as described in the patent EP-A-279880 . This variable opacity element may also in a variant be made with an ink having a low opacity, or even transparent, comprising a photosensitive pigment, for example the radiation of a laser. By selectively treating the ink with the laser radiation, an area of greater opacity is obtained. The photosensitive pigment exposed to the laser radiation changes the optical properties of the treated area to make it more opaque. In another variant, the element 20 is partially deposited on the layers 16 and 17, in addition to covering the intermediate zone 15.

In the above examples, the impressions 11 may be replaced by metallizations, demetallizations or other observable elements.

The optically variable elements can be made otherwise than with orientable magnetic pigments.

For example, the optically variable elements are made using lenticular arrays, as illustrated on the Figures 8 to 11 .

The lenses 30 of the lenticular network are for example cylindrical or hemispherical concave, convex or Fresnel, and are for example arranged in a hexagonal, hexagonal compact or rectangular arrangement. Compact hexagonal means an arrangement according to which the lenses are included in a hexagonal shape with no space between them. Preferably, the lenticular network consists of coplanar hemispherical lenses arranged in staggered rows, hexagonal lenses arranged in "honeycomb" or juxtaposed cylindrical lenses.

The lenticular network may be made by embossing, in particular by thermo-embossing or by embossing followed by ultraviolet crosslinking, or by molding. The lenticular network may be printed and comprise lenses 30 juxtaposed or not, for example formed by UV printing, for example by screen printing, gravure printing, typography, or by inkjet printing.

A first pattern or color may be observable through the lenticular array at a first viewing angle in the first area 31, a second pattern or color observable through the lenticular array at a second angle of view, different from the first angle, in the second zone 32.

For example, for an observation direction, a black color is observed on zone 31 only, as shown in FIG. figure 10 , and for another angle of observation there is reversal of the aspects of the zones 31 and 32, as illustrated on the figure 11 .

The figure 10 corresponds to the aspect for an observation in the direction O of the figure 8 and the figure 9 at the aspect in the direction of observation D of the figure 9 .

The first and second pattern or color may be at least partially identical.

"Same pattern" means a single pattern or image that may have more than one occurrence whose appearance, ie, shape, aspect and / or color, is substantially the same or at least partially identical. For example the pattern is in the form of an alphanumeric symbol or is representative of a symbol, a logo, a character, a landscape, an object ...

According to an exemplary embodiment, disjointed pattern elements 11 are each arranged facing a corresponding lens 30. In the first zone 31, each pattern element 11 is disposed on a first side with respect to the center or axis of the corresponding lens 30, and each pattern element in the second zone 32 is disposed on a second side , opposite to the first side, relative to the center or the axis of the corresponding lens.

Thus, in the first zone 31 each pattern element 11 is arranged in the same manner with respect to the corresponding lens 30. In particular, the pattern elements 11 can be distributed in the same way as the corresponding lenses 30, that is to say with the same spacing pitch and without angular offset so as to avoid any Moiré effect.

Furthermore, a single pattern element 11 is arranged facing a corresponding lens 30. Each lens 30 is therefore associated with a single pattern element 11 to make the pattern element appear and disappear. In particular, it is possible to avoid have multiple pattern elements 11 facing a single lens 30. It is also possible to avoid having several partial images constituting an interlaced image facing a single lens to generate complex optical effects difficult to distinguish.

The pattern elements 11 can be obtained by perforations, deposits and / or voids of material. For example, the pattern elements 11 are obtained by metallization or demetallization of materials selected from: metals, metal compounds, alloys, varnishes or metallic inks, as described in the document EP 279880 . Alternatively, the pattern elements 11 can be obtained by selective printing, in positive or negative, of an ink containing pigments chosen from: carbon black pigments, magnetic pigments, colored pigments, pigments visible under a UV or IR radiation or a mixture thereof.

According to an exemplary embodiment, the distance between the lenticular array and each pattern element 11 is less than or equal to the focal length of the lenses 30 of the lenticular array. The distance between the apex of each lens 30 and the pattern element 11 is preferably greater than the radius of curvature at the center of the lens.

In the case of the example of a truncated hemispherical lens, also called "plano-convex lens", that is to say resulting from the combination of a plane diopter and a spherical diopter, the radius of curvature in the center of a lens, the height and the radius of the lens are linked by the following known formula: H (2Rc - H) = r ² , ie H = Rc - √ (Rc ² - r ² ), in which "Rc" is the radius of curvature at the center of the lens, "H" is the height of the lens, and "r" is the radius of the lens at the plane diopter.

The height of a lens can thus be determined from the radius of curvature and the diameter of the lens. One can therefore advantageously define a compromise between the thickness of the security element and the resolution of the pattern.

A satisfactory compromise between thickness and resolution is preferably obtained for a lenticular array whose lenses 30 have a diameter of between 15 and 50 microns for a radius of curvature of between 10 and 40 microns. By For example, for a lenticular array whose lenses have a diameter of 20 microns, for a radius of curvature of 15 microns the pattern elements 11 are preferably located at a distance of between 20 and 30 microns from the top of the lenses. For example, for a lenticular array whose lenses have a diameter of 50 microns for a radius of curvature of 30 microns, the pattern elements are preferably located at a distance of between 25 and 45 microns.

Preferably, each pattern element 11 is located on one side of the support 10 facing a corresponding lens 30, so as to have a width at most equal to the radius of the corresponding lens. This arrangement makes it possible to make the pattern element 11 appear and disappear in an adequate manner, that is to say that the time of appearance is substantially equivalent to the disappearing time when the observer varies the angle of observation. security thread evenly over time.

With the arrangement defined above, the security thread has a reduced thickness while maintaining a particularly effective appearance and disappearance effect for integration into security documents, even for relatively fine documents such as bank notes. Since banknotes generally have a thickness of about 100 microns, the security threads they carry should therefore not exceed this thickness approximately.

For example, a security thread according to the invention may have a lenticular array comprising a set of identical truncated hemispherical lenses with a diameter of about 50 microns for a radius of curvature of 30 microns and a height of about 14 microns. . In this case, as explained above, the distance d between the vertex of the lenses 30 of the lenticular array and the corresponding pattern elements 11 may be between 25 and 45 micron, for example equal to the radius of curvature at the center of the lenses of the lens. lenticular network. Therefore, the thickness of the security thread thus obtained is about 30 microns, which is particularly suitable for integration into a thin security document such as a banknote. In addition, the lens diameter of 30 microns induces a totally satisfactory pattern resolution for authentication and identification. Finally, the inscription of a pattern element covering a surface corresponding to about half of the surface of a lens implies a pattern element width of about 15 microns, which makes it possible to overcome complicated and expensive registration such as those made by means of a laser for very high resolutions, for example for printing a complete pattern behind each lens as in the case of a magnifying moiré effect.

Each pattern element 11 may be formed on the security wire by metallization and / or demetallization, for example aluminum. The metallization / demetallization processes have a fineness and a definition such that they are difficult to reproduce by printing. The pattern elements 11 may be further inscribed by a printing process such as offset, intaglio, laser, inkjet, micro-lithography, gravure or screen printing, which can be registered in positive or negative.

The pattern elements 11 may be formed by dots having optical diffraction properties of the light which are arranged on a mirror reflecting surface so as to have a high contrast with respect to the surface. The points constituting the pattern elements may be achromatic, i.e. they do not break down white light, and be arranged on a non-achromatic surface.

Alternatively, the pattern elements 11 can be printed with colored or non-colored inks, visible to the naked eye or not, for example inks only visible under ultraviolet or infrared light, opaque, fluorescent, phosphorescent, thermochromic, photochromic, translucent and / or transparent ... In the case of visible printing, the light source used to illuminate the security thread is for example ambient light from the sun or artificial light. In the case of an ink revealed under excitation by a given wavelength, the appropriate lighting device will be used.

In the example of Figures 8 to 11 , the lenticular network consists of a set of hemispherical lenses which are arranged coplanar on the face 19 of the support 10 and arranged in rows or staggered columns. For example, the lenticular array is formed of a plurality of lenses 30 disposed adjacent each other to form a contiguous lens column. This lens column 30 is itself adjacent to another lens column, the lens columns themselves being arranged offset with respect to each other, for example with a shift of about one hemispherical lens radius according to the longitudinal direction of the lens column. This staggered arrangement of lenses allows optimal compaction of the lenses on the face 19 of the support 10, which has the effect of increasing the overall reason resolution for more efficient authentication of the security element. The pattern elements 11 are printed or otherwise made on the face 12 of the support 10.

A third security element 20 extends on the face 12, between the zones 31 and 32 provided with the lenses 30, when the wire is observed from the front.

On the Figures 24 and 25 the lenses are covered by the variable opacity element 60, for example deposited by printing. In particular, the ink is deposited where the area of greater opacity G must be formed.

A first pattern or color may be observable through the lenticular array at a first viewing angle in the first C area, a second pattern or color observable through the lenticular array at a second viewing angle, different from the first angle, in the second zone E.

For example, for an observation direction, a black color is observed on zone C only, as shown in FIG. figure 26 , and for another angle of observation there is an inversion of the aspects of the zones C and E, as illustrated on the figure 27 .

In these examples of Figures 24 to 27 the third security element 20 is visible between the two optically variable elements.

A security document 1 according to the invention comprises at least one security thread 3 as described above, which constitutes a so-called "first level" security element.

The Figures 28 and 29 represent a security document 1, for example a banknote, in which a security thread 3 is inserted in the window, as illustrated, for example, in FIG. figure 17 . The figure 30 represents a section according to XXVIII-XXVIII defined on the figure 28 . At least a portion of the security thread 3 is visible through a window 75, at which it is flush with the surface of the document as shown in FIG. figure 30 . The security thread is positioned so that a face 73 of the substrate 2 supports the face opposite to the variable opacity element 60. In this way, the first and second optically variable elements are only visible in reflected light, from the face 74 of the document on which the variable opacity element 60 is visible.

In the case of incorporation into windows, as in the example of the figure 28 , the surrounding area of greater opacity G preferably has a uniform color substantially identical to the color of the adjacent portion of the face 74 of the document on which the security thread appears. The borderline between security thread 3 and the Security document 1 is thus not clearly visible to an observer, and only areas of less opacity change in appearance when the direction of observation changes.

As illustrated on the figure 31 the security thread 3 can also be disposed on the surface of the security document 1. The security thread 3 is positioned so that the variable opacity element 60 is turned towards the observer.

For an observation direction O, for which one of the optically variable elements appears transparent, the color of the substrate 2 or a pattern printed on the face 74 and located under the zone of least opacity C or E is visible through the variable opacity element 60. For an observation direction Q, the reflecting aspect of the platelet particles in the zones C or E is observed in reflection.

The wire or the document may, however, comprise other "first level" security elements and / or at least one "second level" and / or "third level" security element.

• des colorants et/ou des pigments luminescents et/ou des pigments interférentiels et/ou des pigments à cristaux liquides, notamment sous forme imprimée ou mélangée à au moins une couche constitutive du document,
• des composants, colorants et/ou des pigments photochromes ou thermochromes, notamment sous forme imprimée ou mélangée à au moins une couche constitutive du document,
• un absorbeur ultraviolet (UV), notamment sous forme enduite ou mélangée à au moins une couche constitutive du document,
• un matériau spécifique collecteur de lumière, par exemple du type « guide d'ondes », par exemple un matériau collecteur de lumière luminescent comme les films polymères à base de polycarbonate commercialisés par la société BAYER sous la dénomination LISA^®,
• un film multicouche interférentiel,
• une structure à effets optiques variables à base de pigments interférentiels ou de cristaux liquides,
• une couche biréfringente ou polarisante,
• une structure de diffraction,
• une image embossée,
• des moyens produisant un "effet de moiré", un tel effet pouvant par exemple faire apparaître un motif produit par la superposition de deux éléments de sécurité sur le document, par exemple par le rapprochement de lignes de deux éléments de sécurité,
• un élément réfractif partiellement réfléchissant,
• un filtre coloré.
• un autre foil métallisé, goniochromatique ou holographique,
• une couche à effet optique variable à base de pigments interférentiels ou de cristaux liquides,
• un élément de sécurité plat et de format relativement petit tel qu'une planchette, visible ou non visible, notamment luminescent, avec ou sans dispositif électronique,
• des particules ou agglomérats de particules de pigments ou colorants de type HI-LITE, visibles ou non visibles, notamment luminescents,
• des fibres de sécurité, notamment métalliques, magnétiques (à magnétisme doux et/ou dur), ou absorbantes, ou excitables aux ultraviolets, le visible ou l'infrarouge, et en particulier le proche infrarouge (NIR),
• une sécurité lisible automatiquement ayant des caractéristiques spécifiques et mesurables de luminescence (par exemple fluorescence, phosphorescence), d'absorption de la lumière (par exemple ultraviolet, visible ou infrarouge), d'activité Raman, de magnétisme, d'interaction micro-ondes, d'interaction aux rayons X ou de conductivité électrique.

The document 1 may in particular comprise the following security elements, alone or in combination:

• dyes and / or luminescent pigments and / or interferential pigments and / or liquid crystal pigments, in particular in printed form or mixed with at least one constituent layer of the document,
• components, dyes and / or photochromic or thermochromic pigments, in particular in printed form or mixed with at least one constituent layer of the document,
• an ultraviolet (UV) absorber, especially in the form coated or mixed with at least one constituent layer of the document,
• a light collector specific material, for example of the "waveguide" such a luminescent light collector material such as polycarbonate polymer films marketed by Bayer under the name LISA ^®,
• a multilayer interference film,
• a structure with variable optical effects based on interferential pigments or liquid crystals,
• a birefringent or polarizing layer,
• a diffraction structure,
• an embossed image,
• means producing a "moiré effect", such an effect being able for example to reveal a pattern produced by the superimposition of two security elements on the document, for example by bringing lines of two security elements together,
• a partially reflective refractive element,
• a colored filter.
• another foil metallized, goniochromatic or holographic,
• a layer with a variable optical effect based on interferential pigments or on liquid crystals,
• a flat and relatively small security element such as a board, visible or non-visible, in particular luminescent, with or without an electronic device,
• particles or agglomerates of pigment particles or dyes of the HI-LITE type, visible or non-visible, in particular luminescent,
• security fibers, in particular metallic, magnetic (with soft magnetism and / or hard), or absorbing, or excitable with ultraviolet, the visible or the infrared, and in particular the near infrared (NIR),
• an automatically readable security having specific and measurable luminescence characteristics (eg fluorescence, phosphorescence), light absorption (eg ultraviolet, visible or infrared), Raman activity, magnetism, microwave interaction , X-ray interaction or electrical conductivity.

One or more security elements as defined above may be present in the document and / or in one or more constituent layers of the document or in one or more security elements incorporated in the document and / or in one or more layers constituting the document. , such as a wire, a fiber or a board.

At least one of the constituent layers of the document may also include a first level security element such as a watermark or a pseudo-watermark superimposed at least partially on a translucent region of the document.

To produce a security thread 3 according to the invention, it is possible to start from a film 40. The first optically variable element is produced on the film in the form of spaced parallel strips 51 and the second optically variable element is produced in the form of spaced parallel strips 52, interwoven with the strips 51 formed by the first member, with a spacing between the strips of the first member and the strips of the second member. The film is cut at half the width of the strips of the first member and the strips of the second member to form a plurality of security threads 3.

The strips 51 and 52 are for example between 3 and 5 mm wide.

Two strips 51 and 52 are for example spaced apart by a distance of 0.5 mm.

The deposition of the pigment layers 16, 17 or the formation of the lenses 30 can be done by passing the film to a printing station 48, as illustrated in FIG. figure 13 .

The film 40 is for example unwound a first time before going to the printing station 48, to form the strips 51 corresponding to the pigment layers 16. Then, the film 40 is returned, for example by rotating around a perpendicular to the surface of the film, and reintroduced into the machine to form the strips 52 corresponding to the pigment layers 17. Due to the overturning, the pigments of the layers 16 and 17 are oriented differently on the wire. The film is then cut to form the wires that are wound on multiple coils.

The invention is not limited to the illustrated examples.

The security document including the safety wire may still be a document such as a passport, an identity card, a driving license, an interactive playing or collectible card, a means of payment other than a bank note including a credit card, voucher, voucher, transport card, loyalty card, service card or membership card.

Embodiments of the examples described can be combined within non-illustrated variants.

The thread can be made by implementing the teachings of the patent FR 2 877 609 B1 or request WO 2004/106078 A1 .

• au moins une première zone fluorescente capable d'émettre par fluorescence, dans une condition d'éclairage prédéfinie, une lumière visible d'une première couche,
• au moins une deuxième zone fluorescente capable d'émettre par fluorescence, dans la condition d'éclairage prédéfinie, une lumière visible d'une deuxième couleur, différente de la première, les première et deuxième zones fluorescentes étant respectivement observables depuis des faces opposées du fil.

For example, the thread may include:

• at least a first fluorescent zone capable of fluorescing, under a predefined lighting condition, a visible light of a first layer,
• at least one second fluorescent zone capable of fluorescently emitting, under the predefined lighting condition, a visible light of a second color, different from the first, the first and second fluorescent zones being respectively observable from opposite sides of the wire .

The third security element may constitute one of the fluorescent zones and the other fluorescent zone may be formed in the intermediate zone.

Advantageously, the first and second fluorescent zones are at least partially superimposed so as to constitute the third security element and so that, in the predefined lighting condition, the superposition of the two fluorescent zones appears in transmitted light of a third color, different from the first and second colors.

Authentication and / or identification of an article or document incorporating such a thread may comprise two observation steps, in the predefined lighting condition, in reflection, first and second colors, at least one step of observation in transmitted light to observe the third color.

For example, under UV illumination, in reflection, the first fluorescent zone appears yellow and the second fluorescent zone blue, and, observed in transmitted light, the wire has a violet color when it is observed from a first face and appears substantially white when observed from a second side, opposite to the first.

In addition, the impressions respectively disposed on each side of the intermediate zone under each of the optically variable zones, made for example by means of lenticular arrays or reflective particles, may also be fluorescent and represent patterns. Thus, the two additional steps of observation of the security thread at different angles make fluorescent colors appear, in reflection, preferably different, on each side of the intermediate zone. These colors can also be different from the visible color in reflection in the intermediate zone.

The third security element may comprise a security pattern consisting of a first pattern formed from substances having an interferential effect and a second pattern formed from substances that react to certain stimulations, such as light radiation or heat stimulation, magnetic, electromagnetic, electric or microwave type, giving a visible light response by a human eye or a specific detectable signal using a suitable device.

A simple and particularly attractive technical solution is to apply on a paper or plastic substrate a layer consisting of a proportionate mixture of the two substances: the two patterns will be, in this way, completely identical and will represent the same final security pattern. Advantageously, the first pattern appears in white light and the second pattern appears under stimulation, the two patterns being identical, the observer has the impression of visualizing the transformation of a pattern which is particularly effective in terms of authentication.

This layer may, advantageously, be applied by printing, in particular by gravure printing or by screen printing, and will consist of a proportionate mixture of the substances reacting to certain stimulations, such as light radiation or heat, magnetic, electromagnetic or electrical stimulation, in particular. giving a luminous response visible by a human eye or detectable by a suitable device.

Another technical solution is to apply successively to the security document a layer comprising substances having an interference effect, thereby forming a first security pattern, and a layer comprising substances that react to certain stimulations, such as light radiation or stimulation. heat, magnetic, electromagnetic or electrical, giving a light response visible by a human eye or detectable by a suitable device.

These two motifs may, therefore, be identical, thus finding the result obtained by application of a single layer, either partially superimposed or contiguous, or, still, completely disjoint, resulting in a compound final pattern.

From this point of view, it may be advantageous to provide a final alphanumeric type pattern, in which a part of the signs or letters is formed by the first pattern and the other part of these same signs or letters is formed by the second pattern. .

Under normal observation, that is to say under a white light, the final pattern is unreadable, the letters or signs being half-truncated, for example. On the other hand, under the action of an external stimulation, such as a rise in temperature for example, the final pattern appears in its entirety.

It is also conceivable to provide a final pattern of alphanumeric type, in which some signs or letters are formed by the first pattern and some other signs or letters are formed by the second pattern.

Under normal observation, ie under a white light, the final pattern presents, in this way, a uniform interference effect according to the first pattern, the second pattern then being invisible. On the other hand, under the action of an external stimulation, such as a light emitting ultraviolet radiation for example, the second alpha-numeric type pattern is revealed the time of the stimulation.

• au moins une première composition fluorescente,
• au moins une deuxième composition phosphorescente, les première et deuxième compositions étant excitables simultanément par un illuminant prédéfini depuis une même face de la structure.

The security thread can still include:

• at least a first fluorescent composition,
• at least a second phosphorescent composition, the first and second compositions being simultaneously excitable by a predefined illuminant from the same face of the structure.

Both compositions can be the third security element.

The first fluorescent composition may be superimposed, at least partially, on the second phosphorescent composition.

One of the first and second compositions may form a solid surface which is superimposed on the other of the first and second compositions, which forms at least one pattern.

One of the first and second compositions may form at least one pattern which, upon extinction of the illumination by the predefined illuminant, appears or disappears, or which changes appearance by passing from a positive or negative pattern or from one color to another.

The first fluorescent composition can emit, under the illumination by the predefined illuminant, a visible light of a first color, the second phosphorescent composition emitting, under illumination by the predefined illuminant, a visible light of a second color, different the first, and at least one superposition area of the first and second fluorescent and phosphorescent compositions emitting, under predefined illuminant illumination, visible light of a third color, resulting from the additive synthesis of the first and second colors.

The expressions "comprising one" or "comprising one" are synonymous with "having at least one" or "comprising at least one".

Claims (19)

1. Security thread (3) to be incorporated into a security document (1), comprising at least two zones (31, 32) located respectively on either side of a separation line (X) extending longitudinally along the thread (3), a first optically variable security element (16; 30) in the first zone (31) and a second optically variable security element (17; 30) in the second zone (32), the first and second elements both being at a distance from the separation line (X) and arranged so that the two elements have different appearances from a first direction of observation and have on the one hand changed appearance compared to their appearance from the first direction of observation from a second direction of observation, and on the other hand different appearances.
2. Thread according to claim 1, the separation line (X) being a median line.
3. Thread according to either one of the preceding claims, comprising a third security element (20) extending longitudinally.
4. Thread according to claim 3, the third security element (20) being located at least partially between the first and second optically variable elements when the thread is observed from in front.
5. Thread according to any one of claims 3 to 4, the third element (20) being superposed on or at least partially covering one of the first and the second optically variable elements when the security thread is observed from in front.
6. Thread according to any one of claims 3 to 5, the third security element (20) extending along a continuous or discontinuous strip.
7. Thread according to any one of the preceding claims, the first and second security elements comprising a same pigment (16, 17), which is deposited differently on the first zone (31) and the second zone (32), in particular with a different orientation.
8. Thread according to claim 7, the pigment being reflecting, preferably magnetic and flaky.
9. Thread according to claim 7 or 8, the pigment (16, 17) covering underlying printings (11), in particular identical printings (11), the pigment and the printings (11) preferably being on opposite faces of a support (10).
10. Thread according to either one of claims 3 or 7, the third element extending visually at least partially between the first and second elements and being at least partially superposed on the reflecting particles.
11. Thread according to any one of the preceding claims, the first and second optically variable elements each comprising a lens array, notably an array comprising hemispherical lenses (30).
12. Thread according to any one of the preceding claims, further comprising a variable-opacity element (60) at least partially superposed on the first optically variable element (16) and the second optically variable element (17), defining a first lower-opacity zone (C) and a second lower-opacity zone (E) superposed at least partially with the first optically variable element (16) and the second optically variable element (17), respectively.
13. Thread according to the immediately preceding claim, the area covered by the first and second lower-opacity zones being less extensive than the area covered by the surrounding higher-opacity zone.
14. Thread according to any one of the preceding claims, wherein when observed along the first direction of observation (O) through the first lower-opacity zone (C) and the second lower-opacity zone (E), the first optically variable element (16) and the second optically variable security element (17) appear to be transparent and reflecting, respectively, and when observed along the second direction of observation (D) different from the first, the first optically variable element (16) and the second optically variable element (17) appear to be reflecting and transparent, respectively.
15. Method for fabricating a security thread (13) according to any one of claims 1 to 14 wherein the first optically variable element is produced on a film in the form of spaced parallel strips (51) and the second optically variable element is produced in the form of spaced parallel strips (52) interlaced with the strips (51) formed by the first element, with a spacing between the strips of the first element and the strips of the second element, the film being cut at mid-width of the strips of the first element and the strips of the second element to form a plurality of security threads.
16. Method according to claim 15, the strips (51) being produced during a first passage in front of a print head, the film then being turned over and the strips (52) being produced during a new passage in front of the print head, the change in appearance of the strips (51, 52) during the change in the direction of observation being associated with the overturning of the film during fabrication.
17. A security document (1) including a security thread (3) according to any one of claims 1 to 14, the thread extending from one edge of the document to an opposite edge.
18. A security document (1) including a substrate (2) and a security thread (3), notably according to any one of claims 1 to 14, comprising:

    - a support (10),

    - a first optically variable element (16) disposed on the support (10),

    - a second optically variable element (17) disposed on the support (10), the first element (16) and the second element (17) having a first region (A) and a second region (B), not superposed on the support (10),

    - a variable-opacity element (60) at least partially covering the first region (A) and the second region (B), defining a first lower-opacity zone (C) and a second lower-opacity zone (E) that are at least partially superposed with the first region (A) and the second region (B), respectively, and a surrounding higher-opacity zone (G), the security thread (3) being placed on the substrate (2) so that the first region (A) and the second region (B) are visible through the variable-opacity element (60), the first element (16) and the second element (17) being arranged so that for a first direction (O) of observation the first element (16) and the second element (17) have when simultaneously observed via the first lower-opacity zone (C) and the second lower-opacity zone (E), respectively, different appearances and, for a second direction (D) of observation different from the first (O), the first element (16) and the second element (17) have when simultaneously observed via the first lower-opacity zone (C) and the second lower-opacity zone (E), respectively, on the one hand changed appearances compared to their appearance when observed in the first direction (O) of observation and on the other hand different appearances.
19. Document according to claim 17 or 18, the security thread (3) being placed in a window or windows or being disposed on the surface.

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