FR3028801A1 - SECURITY ELEMENT - Google Patents

Abstract

Security element (10), in particular security thread, for security document, the security element comprising first (18) and second (21) zones separated by an intermediate zone (24) comprising an intermediate structure (33), the first and second zones having respective first (27) and second (30) optically variable structures arranged so that for a first viewing direction (O1) the first and second structures have different aspects than the first one; other and for a second direction of observation (02) different from the first, the first and second structures have each on the one hand each changed aspect with respect to their appearance when observed according to the first direction of observation, and on the other hand have different aspects from each other, the intermediate structure comprising non-magnetic particles and / or a semi-transparent layer.

Description

The present invention relates to security elements, in particular security threads, and security or security documents incorporating such elements. Security features are very often used in banknotes to help make counterfeits more difficult and to authenticate them.

Numerous elements have been described which aim both to provide security difficult to reproduce and to produce a visually appealing appearance. WO 2013/034476 discloses a safety strip having two zones extending in a longitudinal direction of the strip and having different aspects visible by reflection.

It is also known, for example from US Pat. No. 7,047,883, US 2006/0198998 and US 2013/0087060, to orient magnetic pigments deposited on a substrate under the effect of a magnetic field so as to form a security element. having an optically variable structure in which the orientation of the pigments progressively changes, thereby providing a visual appearance of movement as the viewing direction of the security element varies. 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 , an underlying impression. 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. FR 2 976 954 A1 discloses a safety thread comprising two optically variable structures separated in a direction transverse to the longitudinal direction of the wire by a third security structure, comprising platelet pigments oriented differently in the two zones and allowing observation of underlying impressions in respective viewing directions substantially parallel to the orientations of the pigments. FR 2 992 255 A1 discloses a safety wire comprising two optically variable structures extending along the longitudinal direction of the wire, on which is superimposed a layer of variable opacity, the optically variable structures comprising differently oriented pigments in the two zones . When observed through the variable opacity layer, the optically variable structures appear reflective or transparent, depending on the direction of observation.

EP 0 310 707 A2, EP 1 618 006 A1 and WO 2011/026829 describe safety elements comprising regions having areas with various magnetic properties. The distribution of these areas within these security elements defines magnetic signatures that are unique to them and that can be detected magnetically.

The invention aims to further improve the security elements, especially so that these elements offer different levels of visually detectable security, and optionally magnetically, thanks to a security element, including security thread, for secure document, the element of security. a longitudinal zone having an intermediate structure, the first and second zones having first and second respective optically variable structures arranged in such a manner that for a first direction of observation, the first and second structures have different aspects from each other and for a second direction of observation different from the first one, the first and second structures have on the one hand each changed from one to the other. aspect in relation to their appearance when observed according to the first direction of observation, and secondly have different aspects of each other. According to one aspect of the invention, the intermediate structure comprises non-magnetic particles and / or a semi-transparent and preferably semi-reflective layer, which may be defined by non-magnetic particles or by a deposition of a metal. According to another aspect of the invention, the intermediate structure comprises magnetic particles oriented flat. According to another aspect of the invention, the intermediate zone consists of a metal flat surface, preferably semi-reflective. The first and second structures and the intermediate structure may in particular be obtained by embossing a support, in particular covered with metal, for example in the form of a solid, preferably semi-reflecting surface, as described for example in WO 2007 / 079851 and WO 2009/080264. When viewed in reflected light, a semi-transparent structure appears opaque and when observed in transmitted light, it is possible to see through it. The semi-transparency can be obtained by a metal deposit, such as aluminum, including the adjustment of the optical density, that is to say the adjustment of the thickness of the deposited metal layer, allows to modulate the transmittance. The optical density is advantageously chosen between 0.2 and 1.6, preferably between 0.4 and 1. The semi-transparency of a structure comprising particles, for example of platelet-shaped form, dispersed in a binder may be obtained by determining the optical properties of the binder and adjusting the thickness of the structure and the particle size so that in transmitted light, the structure does not appear opaque. A semi-reflecting structure may be such that, when observed in reflection, it exhibits, for at least one viewing direction, an aspect of specular gloss and appears non-opaque, in particular transparent, for a different viewing direction. For example, a structure comprising platelet particles in themselves opaque dispersed in a transparent binder and all oriented in the same direction of orientation may appear non-opaque when observed in a direction parallel to the direction of orientation of the particles and appear opaque, in an oblique direction of observation relative to the large faces of the platelet particles, the incident light beam being reflected by these large faces. A semi-reflective structure may be such that when observed in reflection, it exhibits for at least one viewing direction an aspect of specular gloss, and appears opaque and matte for another viewing direction. A structure can be both semi-transparent and semi-reflective. An interesting visual effect can be obtained by successively placing the first optically variable structure, the intermediate structure and the second optically variable structure in succession with each other. The same visual appearance may pass from the first zone to the second zone when the viewing direction changes, and may also pass through the intermediate zone. In particular, the aspect in question can be the same color, a gloss, for example metallic, a transparency, a shape, a drawing, for example a face or a landscape, or a succession of alphanumeric characters. The security element may extend in a longitudinal direction and the first and second zones may be separated in the longitudinal direction by the intermediate zone. According to a third direction of observation different from the first and second observation directions, the intermediate structure may have an appearance identical to the appearance of the first zone observed in the first direction of observation. It may also have an aspect identical to the appearance of the second zone observed in the second direction of observation.

The first and second optically variable structures preferably comprise the same pigment which is deposited differently on the first and second zones, in particular with a different orientation. This gives a "tilting" effect, for example with a luminous "extinction" of a part of the security element when it is observed in reflected light in a certain direction of observation, and an inversion of the extinction of another part of the security element when changing enough direction of observation. Preferably, this pigment is magnetic and platelet-shaped. It can thus be oriented using magnetic devices during the manufacture of the security element. The first and second optically variable structures and the intermediate structure may be arranged on the same side of a support of the security element, made of a thermoplastic material, preferably polyethylene terephthalate (PET). The first and second optically variable structures and the intermediate structure may be semi-transparent. They can also be scanned. The security element optionally includes a fourth structure superimposed on the first and second optically variable structures and the intermediate structure. The fourth structure can define a pattern, for example a sequence of 20 alphanumeric characters, a drawing, a face, a barcode. The fourth structure thus makes it possible to improve the security of the security element. For example, it is visible in reflected light in a fourth direction of observation and in transmitted light in a fifth direction of observation different from the fourth direction of observation. It may be a magnetic layer, in particular obtained by printing a magnetic ink. The fourth structure 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 structures are detectable only with a relatively simple apparatus, such as a lamp emitting in the ultraviolet (UV) or infrared (IR). These security structures 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 structures are called second level. Other types of security structures require for their detection a more sophisticated detection apparatus. These security structures 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 safety structures 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 structures are said to be third level. The fourth security structure may comprise, or even consist of: - printing, - demetallization, - a magnetic layer, creating a third level security, or - a colored element or effect goniochromatic, metallic, holographic, among others opportunities. The fourth and fifth observation directions may be parallel to the first and second observation directions, respectively. As a variant, they may be different, which advantageously makes it possible to improve the security of the element, by providing multiple aspects according to the directions of observation. The first and second optically variable structures and the intermediate structure may be disposed on one side of a support and the fourth structure may be disposed on an opposite face of the support.

A first aspect can then be observed when the observer is looking at a face of the support in one of the first, second and third viewing directions. When the observer looks at the opposite face in one of the fourth and fifth directions of observation, he can observe another aspect, not observed on the other side. The first optically variable structure and / or the second optically variable structure may overlap underlying impressions. The underlying impressions are preferably disposed between the support and the optically variable structures. Thus, in the case where an optically variable structure appears transparent for a defined viewing direction, the underlying impression can be revealed, and can disappear when, after changing the direction of observation, the optically variable structure appears opaque. The first and second optically variable structures may be semitransparent and shaped so that, when the security element is observed in transmitted light, the underlying printing is visible, and when the element is observed in at least one observation direction in reflected light, the underlying impression is not visible. The security element may comprise a layer defining a first level and / or second level security and superimposed at least partially on the first optically variable structure and / or the second optically variable structure and / or the intermediate structure. . In particular, this layer may be in the form of a pattern chosen from a series of alphanumeric characters, a demetallization, a bar code, a representation of a semitone halftone pattern, in perspective, in particular a portrait. , a landscape, a plant, an animal, or a monument. In particular, said layer may be invisible under an illuminant having at least one wavelength in the spectrum of visible light and be revealed to the eye by an infrared illuminant and / or an ultraviolet illuminant, because it contains a luminescent compound, in particular fluorescent. The intermediate structure is preferably contiguous with the first optically variable structure and / or the second optically variable structure. It is thus possible to obtain a visual effect passing from the first zone to the intermediate zone and then to the second zone, which appears continuous to the observer. The security element may be a wire whose width is between 2 and 10 mm or a foil whose width is between 2 and 45 mm.

Alternatively, the first and second optically variable structures and the intermediate structure are obtained by printing on a substrate of a secure document. Non-magnetic particles Non-magnetic particles are preferably platelet-shaped. They may have opposite major faces which are substantially flat and parallel, for example with a deflection angle of one relative to the other of less than 15 °.

They may have a number-average thickness of between 0.5 μm and 4 μm, preferably between 1 μm and 3 μm, and / or a number-average length of between 10 μm and 60 μm. preferably between 15 μm and 1.1 μm. They may be elongated along a longitudinal axis, and their average length 5 L may be greater than their average thickness e, measured between said main faces, the average form factor L / e being preferably greater than or equal to 2, preferably greater than at 5 or even greater than 10, the averages of the lengths, thicknesses and form factor being expressed in number. Preferably, L / e is between 15 and 25. Preferably, the non-magnetic particles inherently have an opaque character. The non-magnetic particles preferably comprise a metal core, which makes it possible to obtain a metallic reflective effect. The fact of having a metallic core also makes it possible to carry out transformations of the chemical or laser demagalization type or phase modification by means of a laser in order to personalize the intermediate structure. To allow a chemical demetallization, it is preferable not to use metals or anti-corrosion alloys to constitute the heart. The thickness of the metal core layer may be greater than or equal to 100 angstroms. The metals used to make the core may be selected from transition metals and poor metals, especially from aluminum, stainless steel, tin, copper, zinc, titanium, chromium, silver. , gold and their alloys. Examples of pigments that may be suitable as particles according to the invention are described in US 6,686,042 B 1. Preferably, the core of the non-magnetic particles is aluminum. Non-magnetic particles in their entirety may be aluminum, if any.

The non-magnetic particles may be dispersed within a binder so as to form a semi-transparent layer, i.e., when observed in reflected light, appears opaque and which, when observed in transmitted light, lets see through. The binder may comprise any transparent substance allowing a good dispersion and holding of non-magnetic particles, for example a solution of PVA, polyurethane (PU), polyacrylic, etc.

The semitransparency can be obtained by a metal deposit, such as aluminum, whose adjustment of the optical density, that is to say the adjustment of the amount of deposited metal, makes it possible to modulate transmittance. The optical density is advantageously chosen between 0.2 and 1.6, preferably between 0.4 and 1.

The non-magnetic particles are preferably oriented substantially parallel to a plane perpendicular to a direction of observation of the security element, and in this plane are preferably randomly oriented. The thickness of the intermediate structure may be between 2 and 50 microns, better still between 5 and 15 microns. Preferably, the thickness of the semi-transparent layer is less than or equal to 15 μm since this facilitates obtaining a monolayer of non-magnetic particles and therefore particularly satisfactory metal reflection and semi-transparency aspects. The non-magnetic particles can thus be present, within the binder, in the form of a monolayer. The concentration by dry weight of the non-magnetic particles in the layer 15 is preferably between 5 and 50%, relative to the total weight of the binder and said particles, more preferably between 15 and 45%. The volume occupied by the non-magnetic particles within the semi-transparent layer is preferably between 5 and 80%, better still between 20 and 50%, relative to the total volume of the layer. Intermediate Structure The intermediate structure can be customized by a modification showing a pattern in reflected light. This pattern is advantageously formed by laser, which modifies the structure of the non-magnetic particles, in particular the crystalline phase of the metal of the non-magnetic particles to make it amorphous, and therefore more transparent. This conversion can be done by means of an Nd YAG type laser which generates a punctually very high temperature generating the vitrification of the metal at the point of impact. As the laser moves, the metal returns to ambient temperature almost instantaneously, making it possible to freeze the metal in the amorphous or partially amorphous state. It is possible, particularly with regard to this technique, to refer to the publication "Metal surface amorphization regimes during continuous treatment by laser scanning", Metal Fizika i himiâ obrabotki materialov ISSN 0015 3214, 1984, no3, pp. 25-32 (12 ref.), KLEBANOV YU.D; In a variant, the personalization is carried out by selective chemical etching. In this case, the binder can be degraded punctually. Thus, the intermediate structure can be rendered differently in places, in particular more transparent or otherwise reflecting light, which makes it possible to record variable data, for example related to the holder of the secure document incorporating the security element according to the invention, for example his photograph or his name. Preferably, the modification of the intermediate structure takes place without completely losing its semi-transparent character, by not affecting all the non-magnetic particles of the zone whose appearance is to be modified, to the point of their 10 to lose all their reflective and / or opacifying power. The non-magnetic particles of the intermediate structure may, for at least some or all of them, exhibit goniochromatic properties. Thus, it is possible to observe, in addition to an aspect of metallic gloss, a color change of the intermediate zone, during a change in the direction of ob servation. A single non-magnetic particle structure can be used within the semi-transparent layer. The non-magnetic particles may in particular be goniochromatic. In particular, a mixture of particles of the same structure but with different goniochromatic properties can be used, and in this case, the total content of particles according to the invention is chosen so as to obtain the desired result. According to a third aspect, the invention relates to a security element, in particular a security thread, for a security document, comprising a magnetic layer superimposed on at least one optically variable structure comprising magnetic and oriented platelet pigments. The security element may extend in a longitudinal direction and the magnetic layer may extend in this longitudinal direction. A security element according to this third aspect of the invention thus provides visual security and third-level security.

The difference between the remanence measured on a zone of greater remanence, where the magnetic layer is superimposed on the optically variable structure, and the remanence measured on a zone of least remanence, where the optically variable structure is absent, is preferably between 10 nWb / m and 200 nWb / m, preferably between 30 nWb / m and 170 nWb / m. The variation of magnetic remanence along the security element thus makes it possible to define a third level security, for example a magnetic code. The magnetic layer may in particular define a pattern, for example a succession of letters. Preferably, the pattern may be defined by openings through the layer from one side to another in its thickness. The optically variable structure may be disposed on the face of a support of the security element and the magnetic layer be disposed on the opposite side of the support. In this way, the security element provides magnetic security and visually detectable security that is not degraded by the presence of magnetic security. The optically variable structure may cover an underlying impression, which is preferably disposed between the optically variable layer and the face of the support. As previously described, depending on the viewing angle, the printing may or may not be revealed, providing additional security.

The security element may comprise an additional structure comprising non-magnetic platelet particles, spaced from the optically variable structure in the longitudinal direction. Such an additional structure may have all the characteristics of the intermediate structure of the security element according to the first and second aspects of the invention.

The non-magnetic particles are preferably oriented in a direction different from the direction of orientation of the magnetic platelet pigments. The magnetic layer may in particular be superimposed on first and second optically variable structures comprising magnetic and oriented platelet pigments, the first and second optically variable structures being spaced in the longitudinal direction. The orientation of the magnetic platelet pigments of the first optically variable structure is preferably different from the orientation of the magnetic platelet pigments of the second optically variable structure. The magnetic layer may define a pattern selected from a sequence of alphanumeric characters or a bar code in positive or negative for example. It can in particular be obtained by printing, in particular a magnetic ink.

The invention also relates to a method of manufacturing a security element according to the invention. In one aspect, the manufacturing method according to the invention comprises the steps of: a. depositing on a substrate magnetic pigments in the form of first and second strips and non-magnetic particles in the form of an intermediate strip located between the first and second strips so as to form a base film; b. cutting the base film in a direction transverse to the longitudinal direction of a strip deposited in step a), so as to form a security element according to the invention.

In another aspect, the manufacturing method according to the invention comprises the steps of: c. depositing on a substrate at least one material in the form of first and second strips and an intermediate strip located between the first and second strips, so as to form a base film; 15 d. embossing the first and second strips, and preferably the intermediate strip, so as to form a multifaceted structure on the surface of each of the strips, e. optionally, depositing a metal on each multifaceted structure, in particular so as to form a solid surface, f cutting the base film in a direction transverse to the longitudinal direction of a strip deposited in step c) so as to form an element safety device according to the invention. The method according to the invention may further comprise at least one of the following features. The first band and / or the second band and / or the intermediate band may be discontinuous or continuous. The first and second strips and the intermediate strip are preferably parallel, which simplifies the deposition and arrangement of the strips on the substrate. The first band, respectively the second band, and the intermediate band may each have a non-rectilinear longitudinal edge, notably having an aperiodic or periodic or even pseudoperiodic ripple. In particular, the ripple 3028801 12 may be sinusoidal. It can also be crenated or serrated, for example sawtooth. The corrugation may have an elementary pattern repeated periodically, in sinusoidal arch, or triangular, or rectangular or semicircular. The elementary pattern may have a length of between 1 and 10 mm. The corrugation of the longitudinal edge of the first and second strips is preferably imbricated in the corrugation of the longitudinal edge of the intermediate strip. The first band and / or the second band and / or the intermediate band may each have non-rectilinear longitudinal edges, in particular corrugated edges, the two longitudinal edges of a strip being non-rectilinear, each edge having an identical corrugation. Alternatively, a longitudinal edge of a strip may have a corrugation, the edge being for example serrated, and the opposite longitudinal edge may have an identical or different corrugation, the edge being for example crenellated. In step b), the transverse cutting direction is preferably perpendicular to the direction of a strip formed in step a).

In step a), an ink comprising the non-magnetic pigments is preferably deposited on the substrate to form the intermediate strip. It may further comprise a dispersing agent and / or a wetting agent and / or a wax-based additive, in particular a wax in a solvent phase, which makes it possible to improve the dispersion and the orientation of the non-magnetic particles.

The method according to one of the aspects of the invention may be such that step d) of embossing the first and second strips and optionally the intermediate band is implemented before step c) of depositing the strips on the substrate. In step a) a magnetic field is preferably applied to orient the magnetic pigments of the first and second strips. It can be applied between the deposition of the magnetic pigments of the first band on the one hand and the deposition of the magnetic pigments of the second band on the other hand. In particular, it can be applied so that the orientation of the magnetic particles of the first band is different from the orientation of the magnetic particles of the second band. The non-magnetic particles may be deposited in step a) between the deposition of the magnetic pigments of the first band on the one hand and the deposition of the magnetic pigments of the second band on the other hand.

The strips can be made by printing, by deposition of magnetic pigments or non-magnetic particles, by successive passes on the substrate. The substrate can be turned between the passes, which is a simple and effective way to orient the pigment particles differently, if necessary.

The first and second strips can be made such that in a first viewing direction of the base film, the first and second strips are optically variable and have different aspects, and in a second viewing direction different from the first, the first and second strips have each changed appearance and the first band has a different appearance from that of the second band. The first and second strips can be made in such a way that: in a first direction of observation of the base film, the first strip appears of a first aspect, in particular colored, reflecting, transparent, semitransparent or matte, and the second strip a second aspect, different from the first aspect, especially colored, reflective, opaque, transparent, semi-transparent or matte, and that - in a second direction of observation of the base film, different from the first direction, the first band appears with the second aspect and the second band with the first aspect. In particular, the following combinations can be obtained: first matt aspect and second reflective aspect or vice versa, first and second aspects of different colors, first transparent or semi-transparent appearance and second opaque appearance. The first and second strips preferably comprise magnetic and oriented pigments as described above. The magnetic and oriented pigments within the same band may have substantially all the same orientation. The pigments of the first and second strips on the base film may have different orientations, for example symmetrical orientations on either side of a median plane perpendicular to the substrate and the strips or to the cutting direction. The base film may comprise at least one pattern and / or one luminescent layer 30 which is superimposed at least partially on at least one of the strips, especially when these are produced using oriented pigments, and which becomes then visible when one observes in a direction substantially parallel to the direction of orientation of the pigments.

When viewed in a direction substantially perpendicular to the direction of orientation of the pigments, the pattern or the luminescent layer which is superimposed on the pigments is masked and not visible. Each band may also comprise a lenticular network, in particular a network 5 comprising convex lenses, in particular substantially hemispherical lenses. 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. An exemplary lenticular network that may be suitable is described in application WO2012085773. The width of the strips may be between 1 and 30 mm, better between 2 and 15 mm. The bands may or may not have the same width. Two adjacent bands may be separated by an interval. The substrate can then carry a security element at least partially visible in said interval. The spacing between two strips may still be substantially the same on the base film. The spacing between two strips is for example between 0.1 and 3 mm, more preferably between 0.4 and 1 mm. This spacing may be smaller than the width of the strips, better represent between 1/20 and 1/4 of their width. The presence of a spacing between two bands makes it possible, if desired, to have additional security between them. This security may be present on the substrate on the same side thereof as the strips, or alternatively on the opposite side, and be at least partially visible in reflected light, or in transmitted light where appropriate, because of the transparency. of the substrate. The base film may comprise, in particular between two strips and / or at least partially overlapping at least one of the strips, on the side of the same face of the substrate as the strips or the opposite side: - a demetallization, - a magnetic layer, extending in particular in band, creating a third level security, or - a colored element or goniochromatic effect, metallic or holographic, among other possibilities.

The substrate of the base film is preferably synthetic, of thermoplastic material, preferably polyethylene terephthalate. The substrate is preferably transparent, and more preferably colorless.

Each strip made on the base film may be continuous or discontinuous in the direction of its length, and be of uniform appearance or not along its entire length. The invention also relates to a security document comprising a security element according to the invention, according to any of its aspects.

In particular, the security element may be located on the surface or in the window of the security document. In particular, the security element can be arranged in a window of the secured document, the outline of the window having an aperiodic or periodic or even pseudoperiodic ripple. The outline of the window may be sinusoidal, serrated or serrated. The contour may in particular have a periodic repetition of an elementary pattern. The elementary pattern may have a length of between 0.5 mm and 45 mm. Preferably, the outline is crenellated or serrated, the serrations preferably having a triangular or semicircular pattern. Another subject of the invention is a method for authenticating or identifying a document comprising a security element according to any one of the first and second aspects of the invention, in which the change of appearance is observed. first and second optically variable structures, or even the intermediate structure, by changing the observation direction of the security element. The invention also relates to a method for authenticating a document 20 comprising a security element according to the third aspect of the invention and, where appropriate, according to any one of the first and second aspects of the invention, in which which is measured using a suitable device the variation of remanence between different areas of the security element. A "magnetic" material is magnetized under the effect of an externally applied magnetic field, for example by a permanent magnet. In other words, it is ferromagnetic. Iron is a magnetic metal, aluminum is not. By "security document" is meant a valuable document, for example a means of payment, such as a bank note, a check or a restaurant ticket, a lottery ticket, a ticket or a ticket giving access to a cultural or sports event 30 and / or a document for the identification of persons, such as an identity card, a visa, a passport or a driving license.

By "opacity", the attenuation of the intensity of an illuminant passing through a material is considered. 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 a structure which has in different areas of its plane absorption properties different from a predefined illuminant, including visible light.

The expression "having one" is synonymous with "comprising at least one". 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: FIG. FIG. 2 represents isolated and front view, the security element, - FIGS. 3 and 4 illustrate aspects that can be observed on one side of security elements according to the invention. various embodiments, observed in different viewing directions, - Figures 5, 6, 8, 11 and 13 show in longitudinal section different embodiments of a security element according to the invention, - Figure 7 illustrates an alternative embodiment of the intermediate structure, viewed from the front and isolated from the rest of the security element, - Figure 9 illustrates the appearance of a security element according to an embodiment, seen from the front in light transmitted, - FIG. 10 illustrates the variation of measured magnetic remanence in different zones of the security element, FIGS. 12 and 14 illustrate aspects provided by the security elements represented in FIGS. 11 and 13 respectively, observed in different directions of the security element. FIG. 15 represents steps of the method of manufacturing a security element according to the invention; FIG. 16 illustrates with photographs acquired with a scanning electron microscope, the orientations of the magnetic pigments; and FIG. non-magnetic particles within the optically variable structures and the intermediate structure of a security element according to one embodiment of the invention, said structures being seen in longitudinal section; FIGS. 17 and 18 illustrate variants of the security element according to the invention, - Figure 19 illustrates a security element selo The invention has a window of a security document, and FIG. 20 illustrates an alternative embodiment of the method. In the appended drawing, the actual proportions of 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 may not be represented in contact with each other while they may be in practice.

FIG. 1 shows a security document 5 according to the invention, for example a bill, which comprises a substrate 8 and a security element 10 according to the invention in the form of a wire. As illustrated, the security element may extend between two opposite edges 12a and 12b of the document. The security element may be incorporated at least partially in mass into the security document substrate, and only a part of the wire appears visible, for example through one or more windows formed in the substrate. An example of incorporation into a window is described in EP 59056. In FIG. 19, two security elements 10 are arranged in a window, the contour 16 of each window 15 being serrated or crenellated. Thus, the outline defines a shape that can help to attract the observer's gaze to the security element. A serration may in particular be a triangular pattern 18. Preferably, the substrate of the security document incorporating the security element is made of natural fibrous materials, for example cellulose and / or cotton, and / or synthetic fibers. The substrate can also be made from plastic materials, such as for example a Polyart ™ film sold by the company ARJOBEX Ltd. As illustrated in FIG. 2, the security element comprises first 18 and second 21 zones separated along the longitudinal direction X of the security element by an intermediate zone 24. The first and second zones comprise first 27 and second optically variable structures and the intermediate zone comprises an intermediate structure 33. The intermediate structure may be contiguous with the first optically variable structure and / or the optically variable structure. At least one of the first and second optically variable structures and the intermediate structure, or all these structures, can extend transversely from one edge to the other of the security element. The optically variable and intermediate structures may each define a continuous strip extending in the longitudinal direction of the security element. When the security element is viewed from the front, they can also occupy the entire observed face of the security element. They may be in the form of strips, for example having sinuosities, but preferably rectilinear. These strips preferably extend generally in the longitudinal direction of the security element. They may have the same shape, in particular a rectangular shape.

In the variant illustrated in FIGS. 17 and 18, at least a part of the contour of the intermediate structure and at least a part of the contour of the first and / or respectively of the second optically variable structure each have a corrugation 25, 26, 28, 31 aperiodic or periodic. Preferably, the corrugations each have an elementary pattern repeated periodically, preferably forming a crenellated or serrated edge, in particular with a triangular or rectangular elementary pattern. Each elemental pattern can be repeated at least twice. The undulation of the longitudinal edge of the intermediate structure is preferably imbricated in the corrugation of the longitudinal edge of the first and / or respectively of the second optically variable structure.

Figure 17 illustrates a basic slot pattern. In Figure 18, an elementary pattern of length 1 is repeated twice. FIG. 3 illustrates the aspects that can be observed according to different directions of observation of the security element. According to a first observation direction 01, the first 18 and second 21 30 optically variable areas have respective aspects A1 and C1, different from each other. The intermediate zone 24 then has an aspect B 1. According to a second observation direction 02, different from the first observation direction, the first and second optically variable zones have respective aspects A2 and C2, different from the Al aspects. and C1 respectively observed according to the first observation direction. The intermediate zone has an aspect B2 which may be different or identical to the aspect B 1. According to a third observation direction 03, different from the first and second observation directions, the first optically variable zone has the appearance A2 observed in the second observation direction, and the second optically variable zone has the appearance C1 observed in the first direction of observation. The intermediate zone has an aspect B3, which may be different or identical to the appearance B2 observed according to the second observation direction and / or the aspect B1 observed in the first observation direction.

Preferably, the aspects B1 and B2 observed along the first and second directions are identical, and preferably also different from the aspect B3 observed in the third direction. Preferably, the aspects B1 and B2 observed along the first and second directions are identical to one of the aspects of the first and second optically variable zones observed along one of the first and second viewing directions. Preferably, the aspect Al of the first optically variable zone observed in the first direction of observation and the aspect C2 of the second optically variable zone observed in the second direction of observation, are identical. Preferably, the aspect A2 of the second optically variable zone observed in the second direction of observation and the aspect C1 of the first optically variable zone observed in the first direction of observation, are identical. In addition, the respective aspects B1 and C1 of the intermediate zone and of the second optically variable zone observed in the first observation direction may be identical. The respective aspects B2 and A2 of the intermediate zone and the first optically variable zone observed in the second direction of observation may be identical. In addition, for a different direction of observation of the first, second and third viewing directions, the first and second optically variable zones and the intermediate zone may all have the same aspect, in particular already observed along one of these three directions. .

In other words, as illustrated in FIG. 4, according to the first observation direction 01, the first optically variable zone may have a first aspect A and the intermediate zone and the second optically variable zone may have a second aspect. B, different from the first aspect A. According to the second observation direction 02, the second optically variable zone may have the first aspect A and the first optically variable zone and the intermediate zone may have the second aspect B. According to the third direction of observation 03, the first and second optically variable zones may have the second aspect B, and the intermediate zone may have the first aspect A. Thus, when the security element is successively observed along the first, third and second directions of observation, a particularly interesting visual animation is obtained, giving the Observer the illusion that the first aspect A propagates along the longitudinal direction of the security element. There is shown in Figure 5 in longitudinal section a variant of the security element described above, which may be in the form of a wire. The security element comprises a support 35, preferably of a transparent thermoplastic material, for example polyester or PET.

The support is of flattened cross-section, in particular rectangular as illustrated. First 27 and second 30 optically variable structures are disposed on a first face 38 of the carrier in the form of strip-like layers along the wire. Preferably, they comprise platelet reflective pigments, and magnetic pigments. The pigments are oriented differently between the first and second structures, as illustrated in FIG. 5. Preferably, in each of these structures, more than 80% or even more than 90% by number of the pigments have an identical orientation. Thus, for a first observation direction 01 substantially parallel to the orientation direction of the platelets of the pigment, a first transparency effect of the first layer 27 is observed, the pigments of the second layer 30 appearing reflective. For a second observation direction 02 different and substantially parallel to the orientation of the pigments of the second layer, the pigments of the second layer appear transparent and a second effect is observed, the first layer appearing reflective. Thus, first 18 and second 21 optically variable zones are obtained and, for example, the appearance change of the first and second layers, shown in FIG. 4, is observed when the observer moves from the first to the second direction. ob servation. An intermediate structure 33, in the form of a layer, is disposed between the first and second optically variable layers on the same face 38 of the support. In the embodiment of FIG. 5, the intermediate structure is spaced apart from the first and second optically variable layers. Alternatively, as shown in Figure 6, it may be contiguous to said layers. In the embodiment illustrated in FIGS. 5 to 8, the intermediate structure comprises non-magnetic particles 45. As illustrated in FIG. 7, the particles are preferably distributed randomly flat and isotropically within the layer. In other words, the non-magnetic particles do not have a specific orientation in a longitudinal median plane of the layer. With this distribution of non-magnetic particles, an intermediate zone is obtained which, when observed in reflected light, has a substantially opaque metallic gloss appearance for a first set of different viewing directions, and appears dull, ie ie non-glossy for a second set of different directions. The security element, in particular that illustrated in FIGS. 5 to 8, can be made in such a way that the appearance changes of the first and second optically variable zones and of the intermediate zone take place when the observation direction revolves around 20 of a transverse axis, preferably perpendicular to the longitudinal direction of the security element, or alternatively about an axis parallel to said longitudinal direction. Preferably, the first and second optically variable zones on the one hand and the intermediate zone on the other hand appear reflective for different viewing directions, at different angles with respect to a direction of observation from the front of the camera. security element. Preferably, the first and second optically variable zones appear reflective in an observation direction making an angle of between 55 ° and 65 °, preferably between 58 ° and 62 ° relative to a normal to the zones, for incident illumination. parallel to normal.

The intermediate zone appears reflective in an observation direction parallel to a normal to the intermediate zone, for an illumination parallel to the normal to the zone.

In the first and second optically variable structures, the pigments can be oriented according to the axis around which the observation direction must turn in order to observe the desired change of appearance. In an alternative embodiment of the security element, the intermediate structure comprises, or even consists of, a semi-reflective layer formed by depositing a metal on the support. In another variant, the first and second optically variable structures may be made otherwise than with orientable magnetic pigments. For example, they can be performed using lenticular arrays as described in WO2012085773. The security element described in FIG. 8 differs from the element illustrated in FIG. 5 in that it comprises a fourth security structure 48 disposed on the face of the support, referred to as the back, opposite the one 38 on which the first and second optically variable structures and the intermediate structure are arranged, said recto.

The fourth security structure may consist of: - a magnetic tape, which may contain a magnetic code, - a text or other motifs formed by demetallization, - a holographic structure, - a goniochromatic pigment or any other structure with effect of change of color, or - a thermochromic pigment. The fourth security structure may extend continuously or discontinuously in the longitudinal direction of the security element, particularly in band. In particular, the fourth security structure may include openings 54 through it through its thickness. These openings can be superimposed on the intermediate structure. They can define a pattern, for example a sequence of alphanumeric characters, reproducing for example the name of the currency, the nominal value of the denomination, or the name of the issuing bank. These openings may be obtained for example by selective demetallization of a metallized layer.

The openings may be located, where appropriate, in a manner identified with respect to at least one pattern 57 formed by modification, in particular by laser, of the semitransparent layer. For example, when the structure is observed in transmitted light, in the direction V of FIG. 8, illuminating on the side of the intermediate layer 33 and observing through the security element on the side of the fourth structure 48, the back side pattern is not visible, the intermediate layer having an example gray uniform appearance. The back side pattern, formed in the fourth structure, appears. The observed result is substantially the same when the security element is observed in transmitted light, according to V of FIG. 4, illuminating on the back side and observing the front side through the security element. In observation in reflected light of the intermediate structure front side under the incidence VI, as in Figure 6, the front side pattern, for example the name of the holder of the security element, appears in negative writing within a colored flat area with a certain color. As the angle of incidence changes to incidence VII, the color of the solid area changes, with the front side pattern remaining visible. When the security element is observed in back-side reflection, the front-side pattern is not visible and only the back-side pattern is eventually visible. In a variant not shown, the fourth structure comprises platelet pigments, as described above, preferably oriented in a direction 20 different from that of the first and second optically variable structures. The security element, observed according to the back side of the support in a fourth direction of observation, may have a reflective appearance. When the back side of the support is observed in a fifth direction of observation parallel to the oriented pigments, the platelet pigments of the fourth structure may appear transparent.

Preferably, the fourth and fifth viewing directions of the reverse side are different from the first and second viewing directions of the front face. The fourth direction of observation is preferably different from the fifth direction of observation. This produces aspect variations that occur for different angle variations depending on whether the face or back side is observed, increasing the security of the security element. FIG. 9 illustrates the appearance of a security element which differs from that of FIG. 8 only in that the fourth security structure consists of a series of patterns printed on the back of the support, presenting the form of a succession of letters. Thus, when the security element is observed in transmitted light on the front side, this succession of patterns 60 appears to the observer, while it is invisible to the observer when he observes the security element in reflection on the same side. For example, in FIG. 9, there is shown a pattern comprising the letters "AWS" printed on the back side of the support, which appear darker to the observer in transmitted light than the rest of the first and second optically variable zones and the intermediate zone. As will be detailed later, these impressions can be made using a magnetic ink, locally increasing the magnetic remanence of the security element. The fourth structure may have, in addition to the impressions and openings described above, magnetic properties. The fourth structure may be a magnetic material, or be covered with a layer of a magnetic material superimposed on the support.

Figure 10) a) illustrates an embodiment of a security element 10 having such a magnetic layer 48 which extends in a continuous band. This magnetic layer is disposed on the face of the support opposite to that on which are deposited the first 27 and second 30 optically variable structures and the intermediate structure 33. The optically variable structures comprise magnetic particles and the intermediate structure comprises non-magnetic particles . The superposition of the fourth magnetic structure 48 with the first optically defined structure defines a first zone 60 of greater remanence. Similarly, the superposition of the fourth magnetic structure 48 with the second structure defines a second zone 63 of greater remanence.

In addition, the superposition of the fourth magnetic structure 48 with the intermediate structure defines a zone of least remanence 66, where the remanence is lower than in the area of greatest remanence. Figure 10) b) shows the variation AR of remanence R which can be measured along the security element.

The zone of least remanence 66 is particularly situated between the first 60 and second 63 areas of greatest remanence. The succession of the zones of greater and lesser remanence thus makes it possible, in addition to the visually detectable security by appearance change, to define a third-level additional and magnetic security, which can be detected by means of devices making it possible to detect measure the remanence. In particular, the remanence of each of the first and second optically variable structures may be 65 nWb / m and the remanence of the fourth structure may be 300 nWb / m. In this way, the remanence of the zones of greatest remanence 60, 63 can be 365 nWb / m and the remanence of the zone of least remanence can be 300 nWb / m. The transition from a zone of high remanence to a zone of less persistence then results in a variation of the remanence AR of 65 nWb / m. Moreover, to create a specific magnetic code, the lengths over which the structures comprising magnetic pigments on the one hand and comprising non-magnetic particles on the other hand, may be different. On the other hand, the oriented magnetic pigments of the first and second optically variable structures may be of materials having different magnetic properties, and chosen so as to have aspects, for example reflected light gloss, substantially identical. We thus obtain different remanence variations by passing from the first zone of greater remanence to the zone of least persistence on the other hand, and from the second zone of greatest remanence to the zone of least remanence on the other hand, all maintaining identical appearance changes. Figure 11 illustrates another alternative embodiment of the security element, which has optically variable areas. The first 18 and second 21 optically variable zones comprise first 70 and second 73 impressions, arranged between the first 27 and second 30 optically variable structures respectively on the one hand, and the support 35 on the other hand. The prints can be directly made on the support, as is the case in FIG. 11, or alternatively on an independent transparent layer, for example made of PET, laminated by means of an adhesive on the rest of the element. of security. Thus, the security element may comprise a multilayer support. The first and second impressions may have a colored background corresponding, where appropriate, to different colors of the goniochromatic particles of the intermediate structure. Furthermore, the first and second impressions may comprise a pattern corresponding, if necessary, to a pattern formed by modification, in particular laser, of the semi-transparent layer 33.

Thus, as shown in FIG. 12) a), according to the first observation direction 01, the oriented plates of the first optically variable structure appear transparent and the first underlying impression 70 is revealed. As an illustration, in FIG. 12, the first underlying impression comprises the succession of 5 letters "AWS" on a colored background. The second optically variable zone and the intermediate zone appear reflective. According to the second observation direction 02, as illustrated in FIG. 12) d), the second underlying impression 73 is revealed, and the other zones appear reflective. The second underlying print may have a pattern, for example with the letters "AWS", on a colored background. In particular, the colors of the pattern and the background of the first and second impressions may be different. For the third observation direction 03, as illustrated in FIG. 12) b), the optically variable structures appear reflective. In addition, the intermediate zone appears opaque. The pattern 72 formed in the semitransparent layer for example comprises the same succession of letters "AWS" as the first underlying impression. In particular, the pattern and the background observed along the third direction 03 in the intermediate zone may have the same colors as the pattern and the background observed in the first optically variable zone in the first direction of observation. For another observation direction 03 ', as shown in FIG. 12) c), the optically variable structures appear reflective and the intermediate zone appears opaque. However, with respect to the aspect observed in the third direction, the color of said pattern has changed thanks to the goniochromatic properties of the non-magnetic particles. In particular, the pattern and the background observed in the other direction 03 'in the intermediate zone may have the same colors as the pattern and the background observed in the second optically variable zone in the second observation direction. Thus, a particularly interesting visual effect is obtained, where a color variation of a pattern and the background on which it rests is added to the animation provided by the appearance / disappearance of the pattern in the different observation areas. FIG. 13 shows an embodiment of a safety wire in which a variable opacity structure 80 is superposed on the first 27 and second 30 optically variable structures and on the intermediate structure 33.

The superposition of the variable opacity structure with the structures 27 and 30 defines first 83 and second 86 zones and an intermediate zone 89 all of less opacity. These zones of least opacity 83, 86, 89 overlap at least partially with the first 18 and second 21 optically variable zones and with the intermediate zone 24. In addition, this superposition defines a surrounding zone of greater opacity 92, extending around areas of less opacity. Thus, a particular visual appearance, in particular a bright reflection effect, can pass from the first zone of least opacity to the second zone of least opacity and / or to the intermediate zone of least opacity with a change in the direction of observation. an optical characteristic of the zone of greater opacity (in particular its color) being for example conserved. A variation in the appearance of the first and second optically variable structures as well as the intermediate structure, through the areas of less opacity, is obtained by choosing the suitably variable opacity structure. Thus, it is possible to define 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 element an optically variable. As shown in FIG. 13, the optically variable structure may consist of an opaque layer 80, defining an area of greater opacity, and having apertures 95, preferably passing through the opaque layer from side to side. These openings thus define an area of less opacity. The security element as illustrated in FIG. 13 further comprises first 70 and second 73 impressions, arranged as previously described with respect to the example of FIG. 11. The prints may consist of a bottom of uniform color and the variable opacity structure may have the same color as the background. Thus, when the first and second optically variable structures are observed in directions such that they do not appear to be reflective, for example according to the first 01 and second 02 observation directions, the first and second optically variable zones appear opaque with a uniform color.

The non-magnetic particles of the intermediate structure can be chosen so that, under the third direction of observation, they have the same effect, and in particular the same color, as the zone of greater opacity. In Figs. 14) a) to 14) c), various aspects observed according to the first to third viewing directions are shown respectively. According to the first observation direction 01 (FIG. 14a)), the platelet particles of the first structure are "transparent" and reveal the underlying impression, which corresponds to a background having the same color as the zone of greater opacity. By "transparent" it should be understood that the platelet particles of the first structure are oriented in substantially the same manner as the first observation direction 01. Thus, for this direction of observation, the appearance of the first optically variable zone is monochrome. The second optically variable structure and the intermediate structure are reflective for this first observation direction. Since the opaque structure defines a zone of less opacity in the form of a succession of letters, the observer only sees this succession of letters shining. The same is true for the first zone and the intermediate zone of least opacity for the second observation direction (Figure 14) (c)). For the third observation direction 03, the succession of letters appears bright in the first and second areas of least opacity, the platelet particles 20 being reflective. The non-magnetic particles of the intermediate zone appear in a color identical to that of the optically variable structure, which does not allow the observer to detect the intermediate zone of less opacity (FIG. 14) b)). Alternative embodiments of the security element illustrated in FIG. 14 may comprise a variable opacity structure which may have the characteristics described in FR 2 992 255 A1. For example, the optically variable structure may be superimposed at least partially , or even totally, to the first and second optically variable structures and to the intermediate structure. For visible light observation, the variable opacity structure can be obtained by metallization / demetallization. This structure comprises a surrounding area of greater opacity, corresponding to a metal layer, and areas of less opacity corresponding to openings resulting from demetallization. In visible light, the metal layer appears completely opaque, and the openings are transparent. In another example of implementation of the invention, for an observation under a UV or IR illuminant, the variable opacity structure comprises an impression, on the zone of greater opacity, with an ink comprising a transparent pigment when 'observed in visible light, but opaque when illuminated under UV or IR. The variable opacity structure may completely or partially cover the first and second optically variable structures and the intermediate structure. The area covered by the first and second zones and the intermediate zone of lesser opacity may be less extensive or, on the contrary, larger than the area covered by the surrounding area of greater opacity. The area covered by the first and second zones and the intermediate zone of less opacity may be 1.5 times, preferably twice, more preferably 3 times, even 5 times, or even even 10 times, less extensive than the covered area. by the surrounding area 15 of greater opacity. One can define first and second zones and an intermediate zone of less opacity taking the form of letters, a text, a pattern, a drawing. In this way, it is possible in particular to focus on these first and second zones and intermediate zone of less opacity the attention of the observer who authenticates a document comprising such an element.

Preferably, the variable opacity structure extends longitudinally along the support, and may be in the form of a strip. 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 structure is from 1 to 10 mm, more preferably from 4 to 8 mm. The variable opacity structure may have opacity depending on the type of illuminant used for the observation. The variable opacity structure may comprise or be constituted by: 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 3028801 can be found elsewhere on the document that integrates the security element; 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; dielectric structures having a mirror or interference effect consisting of alternating layers of high and low indices, for example hafnium dioxide and silica, for example obtained by ion etching, may be used; a structure made of a colored material or with a goniochromatic, metallic, holographic effect, among other possibilities, in order to vary the opacity of the structure over predefined zones; a structure made of a material whose opacity may vary, for example, by selective application to defined zones of a heat treatment or a laser treatment; - a structure obtained by embossing, especially hot, a material with initial homogeneous light absorption properties, so that the change 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, 20 opaque in visible light, fluorescent, phosphorescent, thermochromic, photochromic, translucent and / or transparent. To manufacture a security element as described in the previous examples, it is possible to implement the method illustrated in Figure 15 and described below. A first band which comprises magnetic pigments, as described above, is deposited on a substrate 100, for example PET. To perform this deposition, the metallic pigments can be dissolved in a solvent, for example an ink. The solution obtained has rheological properties, in particular a viscosity, adapted so that the solution can be easily spread on the substrate. The solution can be deposited, for example by printing, in particular by flexography, gravure printing and screen printing with a relative displacement of the print head relative to the substrate to form the first strip 103.

The magnetic pigments 40 of the first band, at the end of their deposition on the substrate, are generally oriented substantially randomly (FIG. 15) a)). In Fig. 15 (a), only a first band is illustrated. Of course, a succession of first bands can be deposited. These first strips can extend parallel to each other. Preferably, the difference between two successive first bands is greater than 2 times, or even 3 times, the width of a first band. The first bands may or may not have the same width. They can in particular be deposited in a single pass. An intermediate band 106, comprising non-magnetic particles 45 as previously described, is deposited next to the first band so as to extend parallel to the first band. In the embodiment shown in Fig. 15) b), the first band and the second band are spaced apart. However, they can be contiguous to each other along their length. The intermediate band is preferably disposed on the same side of the substrate 15 as the first band. Preferably, the intermediate strip is deposited by printing an ink comprising the non-magnetic particles. Preferably, the non-magnetic particles have an average thickness of between 0.5 μm and 4 μm, preferably between 1 μm and 3 μm, and / or an average length of between 10 μm and 60 μm, preferably between 15 μm and 30 μm. Thus, they disperse easily in the ink, and once deposited on the substrate, they are oriented flat, that is to say substantially parallel to the longitudinal median plane of the substrate. Preferably, once their deposition has been carried out, the particles of the intermediate band are oriented flat and in a substantially random manner, when observed in a direction of observation perpendicular to the substrate. To improve the dispersion of the particles in the intermediate band, the ink may comprise a dispersing agent chosen from the group formed by the Byk® brand Disperbyk® produced by ALTANA and their mixtures and / or an additive based on wax, for example chosen from the group of Cerafax® brand Byk® and mixtures thereof.

Such additives make it possible to limit the sedimentation of non-magnetic particles within the ink.

As described above for the first bands, it is conceivable to deposit a succession of intermediate bands, each intermediate band being deposited between two successive first bands. Preferably, each intermediate band is deposited so that a second band comprising magnetic particles can be deposited between the intermediate band and one of the first two successive bands. The intermediate bands may or may not have the same width. They can be filed in one pass. After the deposition of the first band and the intermediate band, a magnetic field is applied to the first band, by means of a magnetizer 107, so as to orient the magnetic pigments of the first band according to a desired direction. The oriented magnetic pigments preferably have an orientation in a direction which is oblique with respect to the longitudinal median plane of the substrate. FIG. 16) a) illustrates a substrate 100 covered with an ink 108 comprising magnetic pigments 40 and oriented substantially in an orientation direction D1.

The particles 45 of the intermediate strip being non-magnetic, their orientation is not affected by the application of the magnetic field. They thus retain the orientation resulting from their deposition, as observed in Figure 16) b). A second strip 109 having magnetic pigments 40 is then deposited along the intermediate strip so that the intermediate strip is disposed between the first and second strips. The second band is preferably disposed on the same face of the substrate as the first face and / or the intermediate band. Preferably, the first and second strips and the intermediate strip are located on the same face of the substrate.

The second strip may be deposited using an ink comprising the magnetic pigments. Preferably, the magnetic pigments of the first and second strips are identical. Preferably, the ink deposited to form the first band is identical to that deposited to form the second band. In particular, once the ink is deposited, the particles of the second band are dispersed and oriented in a random manner, as the particles of the first band before the application of a magnetic field (FIG. 14) (d)). .

The second strips may be deposited as a succession of second strips, particularly in a single pass. In particular, they may be deposited so that the assembly constituted by the succession of a first band, an intermediate band and a second band forms a pattern which repeats itself regularly on the substrate. Preferably, the deposition of the magnetic pigments to form the first and second strips and the deposition of the non-magnetic particles is performed with the same deposition machine, so the same application method, for example the same printing machine.

The first band and / or the second band and / or the intermediate band may extend entirely from one edge to an opposite edge of the substrate, or as illustrated in Figure 15, they may be shorter in length than the distance edge to edge of the substrate, measured in the direction in which the strips extend. On the other hand, in the base film illustrated in FIG. 20, the first band and the intermediate band 106 each have a non-rectilinear and castellated longitudinal edge 104, 107, the crenellations of the longitudinal edge of the first band being nested in the crenellations of the edge. longitudinal of the intermediate band. The second band and the intermediate band 106 each have a longitudinal edge 110, 105 non-rectilinear and crenellated, the crenellations of the longitudinal edge of the second band being interleaved in the crenellations 20 of the longitudinal edge of the intermediate band. For example, in FIG. 20, the corrugations of the longitudinal edges of the first strip and the interleaved intermediate strip each have a triangular elementary pattern of length 1 repeated periodically. Once the second strip has been deposited, a magnetic field 110 is applied so as to orient the magnetic pigments of the second strip in a desired direction (FIG. 14) e)). This magnetization device 110 gives the pigments of the second band a specific orientation. As an illustration, in FIG. 16) c) the substrate 100 is covered with an ink 108 comprising magnetic pigments 40 oriented substantially in a direction of orientation D2, different from D1.

The magnetic field can be applied to the whole of the substrate 100. It is then preferable, before applying said magnetic field, to ensure that the magnetic pigments of the first strip are fixed within the binder which forms them. contains, so that their specific orientation is not modified by the application of the magnetic field. Alternatively, the magnetic field can be applied locally, so that the effects it generates are felt only in the second band.

Preferably, the magnetic fields applied to orient the magnetic pigments of the first and second strips are chosen so that the pigments of the first strip have an orientation symmetrical with those of the second strip, with respect to a plane extending parallel to said strips and normal to one side of the substrate. A base film 112 is thus obtained, comprising the substrate 100, the first 103 and second 109 strips comprising oriented pigments and an intermediate band. In another variant not shown, magnetic pigments and non-magnetic particles are deposited to form respectively first and second bands on the one hand and an intermediate band on the other, then magnetic fields are applied to the first and second bands to orient the magnetic pigments. The deposition of the pigments and particles can be carried out simultaneously in a single pass. The application of the magnetic fields to the first and second bands can be performed jointly, in a single operation. The base film 112 is then cut, so as to form a security element 20 according to the invention. Preferably, the cut is made in a direction perpendicular to at least one of the directions in which the first and second strips and the intermediate strip extend, preferably perpendicular to all these directions. Thus, a security element is obtained in which the portions of the first web, intermediate web and second web resulting from the cutting define first respective optically variable structures, intermediate structure and second optically variable structure. In a particularly preferred embodiment, not illustrated, the method further comprises a step of depositing, preferably on the face of the substrate opposite to that where the first and second strips and the intermediate strip are deposited, a magnetic material, for example diluted in a solvent to form an ink.

This deposition step of a magnetic material may be performed before or after step a) of depositing the first and second strips and the intermediate strip. It is preferably performed before the step of cutting the substrate covered by said strips. The magnetic material may be layered, in particular in the form of a strip, extending for example in a direction perpendicular to that in which the first and / or second strip and / or the intermediate strip extend. . The layer of magnetic material is superimposed at least partially, or totally, on said strips. It can also partially or completely cover the corresponding face of the substrate. It can also be formed in successive steps of metallization / metallization, leaving open patterns, for example one or more letters or an image. The deposition of the magnetic layer can be performed by printing, for example ink jet. By cutting a film comprising such a magnetic material, it is thus possible to obtain a security element according to the invention comprising a fourth structure as described above.

Claims (47)

REVENDICATIONS1. Security element (10), in particular security thread, for security document (5), the security element comprising first (18) and second (21) zones separated by an intermediate zone (24) comprising an intermediate structure ( 33), the first and second zones having respective first (27) and second (30) optically variable structures, arranged such that for a first viewing direction (01) the first and second structures have different aspects than the first and second one of the other and for a second direction of observation (02) different from the first, the first and second structures have on the one hand each one changed aspect with respect to their appearance when observed in the first direction of observation, and on the other hand have different aspects from each other, the intermediate structure comprising non-magnetic particles (45) and / or a semi-transparent layer. 2. Security element according to the preceding claim, wherein the semi-transparent layer is semi-reflective. 3. Security element according to any one of the preceding claims, wherein when the element is observed in a third direction of observation different from the first and second directions of observation, the intermediate zone has a similar appearance to that of the first zone observed according to the first direction of observation and / or that of the second zone observed along the second direction of observation. 4. Security element according to any one of the preceding claims, wherein the first and second optically variable structures each comprise a faceted structure, preferably obtained by embossing, optionally covered with a metal, in particular in the form of a flat metal . 5. Security element according to any one of the preceding claims, wherein the first and second optically variable structures comprise the same pigment which is deposited differently on the first and second zones, in particular with a different orientation. 6. Security element according to the preceding claim, wherein the pigment 30 is magnetic and platelet-shaped. 3028801 37 7. Security element according to any one of the preceding claims, wherein the first and second optically variable structures and the intermediate structure are arranged on the same side (38) of a support (35). 8. Security element according to the preceding claim, wherein the support 5 is made of a thermoplastic material, preferably PET. 9. Security element according to any one of the preceding claims, comprising a fourth structure (48) superimposed on the first and second optically variable structures and the intermediate structure. 10. Security element according to the preceding claim, wherein the fourth structure defines a pattern. 11. Security element according to one of claims 9 and 10, wherein the fourth structure is visible in reflected light in a fourth direction of observation and in transmitted light in a fifth direction of observation different from the fourth direction of observation. 15 12. Security element according to any one of claims 9 to 11, wherein the fourth structure is a magnetic layer, in particular obtained by printing a magnetic ink. 13. A security element according to any one of claims 9 to 12, wherein the fourth structure is disposed on the face (51) of the support opposite to that on which the first and second structures and the intermediate structure are disposed. A security element as claimed in any one of the preceding claims, wherein the first optically variable structure and / or the second optically variable structure and / or the intermediate structure cover underlying impressions (70; 73). 25 15. Security element according to the preceding claim, wherein the underlying impressions are arranged between the support on the one hand and the first and second optically variable structures and the intermediate structure on the other. 16. A security element according to one of the two immediately preceding claims, wherein the first and second optically variable structures are semitransparent and shaped so that when the security element is observed in transmitted light, the underlying printing is visible, and that when the security element is observed in at least one observation direction in reflected light, the underlying printing is not visible. 5 17. The security element of any of the preceding claims, wherein the non-magnetic particles are platelet. 18. Security element according to the preceding claim, in which the non-magnetic particles have an average thickness of between 0.5 μm and 4 μm, preferably between 1 μm and 3 μm, and / or an average length of between 10 μm and 10 μm. Fun and 60 pm, preferably between 1.1, M and 30 gni. 19. Security element according to any one of the preceding claims, wherein the non-magnetic particles are at least partially or completely of aluminum. 20. The security element of any of the preceding claims, wherein the non-magnetic particles are semi-reflective and / or goniochromatic. 21. Security element according to any one of the preceding claims, wherein the non-magnetic particles are dispersed within a binder so as to form a semi-transparent layer, preferably semi-reflective. 22. A security element as claimed in any one of the preceding claims, wherein the non-magnetic particles are randomly oriented and substantially parallel to a plane, preferably perpendicular to a front viewing direction of the security element. 23. Security element according to any one of the preceding claims comprising a layer defining a first level security and / or second level 25 and superimposed at least partially on the first optically variable structure and / or the second optically variable structure. and / or the intermediate structure. 24. Security element according to the preceding claim, wherein the layer defines a pattern selected from a series of alphanumeric characters, a demetallization, a bar code, a semitone halftone image representing a subject in perspective, including a portrait. , a landscape, an animal, a plant or a monument. 3028801 39 25. Security element according to one of the two immediately preceding claims, the layer being invisible under an illuminant having at least one wavelength in the spectrum of visible light and being revealed to the eye by an infrared illuminant and / or or an ultraviolet illuminant. 5 26. A security element according to any one of the preceding claims, wherein at least a portion of the contour of the intermediate structure and at least a portion of the contour of the first, and / or respectively of the second optically variable structure, each have a corrugation (25; 26; 28; 31). 27. Security element according to the preceding claim, in which the corrugations each have an elementary pattern (104; 105; 107; 110) defining a crenellated or serrated contour, in particular with a triangular or rectangular elementary pattern. 28. Security element according to the preceding claim, the elementary pattern being repeated periodically and preferably at least twice. 29. A security element according to any one of the three preceding claims, the undulation of the longitudinal edge of the intermediate structure (25; 26) being embedded in the corrugation of the longitudinal edge of the first (28), and / or respectively the second optically variable structure (31). 30. A manufacturing method comprising the steps of: a, depositing on a substrate (100) magnetic pigments in the form of first (103) and second (109) strips and non-magnetic particles in the form of an intermediate strip ( 106) between the first and second strips to form a base film (112); b. cutting the base film in a direction transverse to the longitudinal direction of a strip deposited in step a) so as to form a security element (10) according to any one of the preceding claims. 31. A manufacturing method comprising the steps of: c. depositing on a substrate (100) at least one material in the form of first (103) and second (109) strips and an intermediate strip (106) located between the first and second strips so as to form a base film (112) ); 3028801 40 d. embossing the first and second strips, and preferably the intermediate strip, so as to form a multifaceted structure on the surface of each of the strips, e. optionally, depositing a metal on each multifaceted structure, preferably so as to form a solid, 5 f. cutting the base film in a direction transverse to the longitudinal direction of a strip deposited in step c) so as to form a security element (10) according to any one of claims 1 to 26. 32. The method according to the preceding claim, wherein step d) is carried out before step c). 10 33. Method according to one of the three immediately preceding claims, wherein the first band and / or the second band and / or the intermediate band is (are) discontinuous. 34. Method according to the preceding claim, wherein the first band and / or the second band and / or the intermediate band is (are) continuous. 15 35. Method according to the preceding claim, wherein the first and second strips and the intermediate strip are parallel. 36. The method of any one of claims 30 to 35, wherein the first strip, the second strip, and the intermediate strip each have a non-rectilinear longitudinal edge, in particular having a corrugation. 20 37. Method according to the preceding claim, wherein the corrugation has a periodic pattern (104; 105; 107; 110) repeated periodically, and defining a crenellated or serrated contour, in particular triangular or rectangular elementary pattern. 38. A method according to any one of the two preceding claims, the corrugation of the longitudinal edge of the first strip (104), respectively of the second strip (110) being embedded in the corrugation of the longitudinal edge of the intermediate strip. (105; 107). 39. A method according to any one of claims 30 to 38, wherein in step b), the transverse cutting direction is perpendicular to the direction of a strip formed in step a). 3028801 41 40. The method of any one of claims 30 and 33 to 39, wherein a. step a), an ink comprising the non-magnetic pigments is deposited on the substrate to form the intermediate band. 41. Method according to the preceding claim, wherein the ink further comprises a dispersing agent and / or a wetting agent and / or a wax-based additive, in particular a wax in a solvent phase. 42. A method according to any one of claims 30 and 33 to 41, wherein in step a) a magnetic field is applied to orient the magnetic pigments of the first and second strips. 10 43. Method according to the preceding claim, wherein the magnetic field (107) is applied between the deposition of the magnetic pigments of the first band on the one hand and the deposition of the magnetic pigments of the second band on the other hand. 44. A method according to any one of claims 42 and 43, wherein the magnetic field is applied so that the orientation of the magnetic particles of the first strip is different from the orientation of the magnetic particles of the second strip. . 45. Process according to any one of claims 30 and 33 to 44, in which the non-magnetic particles are deposited in step a) between the deposition of the magnetic pigments of the first band on the one hand and the deposition of the magnetic pigments. of the second band on the other hand. 46. Secure document incorporating a security element according to any one of claims I to 29. 47. Secure document according to the preceding claim, wherein the security element is arranged in window, the contour (16) of the window having a corrugation.