EP2598693B1 - Security structure including phosphorescent and fluorescent compositions - Google Patents

Description

The present invention relates to security structures intended to combat counterfeiting of identity or valuable documents.

The invention relates more particularly to security structures comprising luminescent substances. The term “luminescent substance” should be understood to mean a fluorescent or phosphorescent substance.

Various security structures incorporating luminescent substances are known.

So the demand FR 2 877 609 discloses a security thread comprising first and second fluorescent zones emitting lights of different colors.

Requirement FR 2 866 036 discloses a flat security element which may incorporate a fluorescent or phosphorescent substance.

Requirement EP 2 028 017 discloses a security structure comprising two openwork opaque layers, a first fluorescent layer being located between the first and second openwork opaque layers and a second fluorescent layer being located so as to be separated from the first fluorescent layer by one of the openwork opaque layers .

Requirement US 2002/0160188 describes a security fiber comprising juxtaposed luminescent components capable of emitting blue fluorescence and red fluorescence side by side.

Requirement US 2006/0014045 describes the possibility of applying a mixture of a fluorescent substance and a phosphorescent substance on a polymer layer of a security film.

Requirement EP 0 303 725 discloses a security thread having an at least partial superposition of phosphorescent and / or fluorescent substances.

There is a need to further improve security structures incorporating luminescent substances, in particular in order to create new effects with the aim of making them more attractive to the observer, while being difficult to counterfeit and offering observable security to the user. naked eye or under low magnification and appropriate lighting.

• 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 première face de la structure.

The subject of the invention is thus, according to one of its aspects, a security structure, as defined in claim 1 or 2, comprising:

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

The predefined illuminant is a UV or IR illuminant, preferably UV at 365 nm.

Thanks to the invention, when the first and second compositions are excited by said illuminant, the lights emitted by fluorescence and phosphorescence can combine or juxtapose according to the configurations of the security structure, and produce an optical effect which is different from that observable after extinction of the illuminant, where only the light emitted by phosphorescence is likely to be perceived by the observer.

The structure can be arranged so that the excitation of the compositions and the observation of the luminescence can only be done from one side of the structure.

As a variant, the structure can be arranged so that the excitation and the observation can be done from each of the faces of the structure.

The first and second compositions can be arranged on the structure so as to be at least partially offset when the structure is viewed from either side of the structure, and this that the illuminant is placed on the side of the structure. 'one or the other of the faces, that is to say during an observation in reflected or transmitted light. The first and second compositions can be superimposed at least partially, when the structure is observed from one or the other of the faces of the structure, and this that the illuminant is placed on the side of one or the other of the structure. faces, that is to say during an observation in reflected or transmitted light.

In an exemplary embodiment, one of the first and second compositions forms a solid area which is superimposed on the other of the first and second compositions, which forms at least one pattern.

The flat area can cover all or part of the structure. The solid is for example defined by the fluorescent composition while the second phosphorescent composition defines the pattern. In one variant, the solid is defined by the phosphorescent composition while the fluorescent composition defines the pattern.

In an exemplary embodiment, one of the first and second compositions forms at least one pattern which, when the lighting is switched off by the predefined illuminant, appears or disappears, or which changes appearance from a positive to negative pattern or from one color to another.

Thus, the contrast of the pattern with respect to its immediate environment can be modified between the state in which the first and second compositions are illuminated by the predefined illuminant and that in which they are no longer, the modification of the contrast resulting for example from a change in color of the pattern and / or of its immediate environment, or of the light intensity of the pattern and of its immediate environment.

The first and second compositions can be deposited by printing or by depositing a varnish, one for example completely covering the other or one being placed next to the other without covering it. One can still be arranged with partial superposition only on the other.

The first and second compositions can emit by luminescence the same color, with substantially the same intensity or with different intensities.

When the first and second compositions emit the same color with substantially the same intensity, it may be advantageous to form a solid with one of the compositions and to deposit the other composition in the form of at least one pattern. In the case of at least partial superposition of the first and second compositions with the pattern which is defined by the phosphorescent composition and the solid by the fluorescent composition, when the structure is illuminated under the predefined illuminant, the pattern does not can be observed in the areas of superposition of the compositions because the light emitted by the solid mask the pattern, while when the illumination ceases, the light emitted by the phosphorescent composition makes it possible to observe the pattern, either in positive writing if the phosphorescent composition is deposited in the form of an impression in positive writing, or in negative writing if the phosphorescent composition is deposited in the form of an impression in negative writing.

By “substantially of the same intensity”, it should be understood that the difference in luminosity is not detectable with the naked eye.

In a variant, the phosphorescent and fluorescent compositions emit by luminescence the same color but at different intensities. In this case, under the predefined illuminant, it is possible to make a pattern appear in positive and this pattern becomes negative after extinction of the illuminant, this is the case for example if the fluorescent composition forms a pattern and is of greater intensity than the composition phosphorescent which surrounds the pattern, or conversely the pattern appears in negative under the illuminant then in positive after extinction of the illuminant.

Preferably, the phosphorescent composition is located on the fluorescent composition.

It is understood that the change in appearance of a pattern from positive to negative, or vice versa, means that the pattern is still discernible but that its interior color or intensity is modified compared to the background, that is to say by relative to the color or intensity that surrounds the pattern.

The phosphorescent and luminescent compositions can still luminescently emit different colors. In this case, it may be advantageous for the compositions to overlap at least partially. Under lighting with the predefined illuminant, it is then possible to observe, in a zone of superposition of the first and second compositions, a visible light of a third color, which results from the additive synthesis of the lights emitted by luminescence respectively by the phosphorescent composition and by the fluorescent composition. It may also be advantageous for at least certain areas, the compositions not to overlap, so as to make it possible to observe their own colors.

The first and second compositions can be applied to the mark on the safety structure, in particular when they are juxtaposed. The first composition can form at least one positive unit and the second composition at least one negative unit, preferably complementary to the positive unit, placed at the mark. The arrangement at the reference point for the compositions can be done on the same face of a support of the structure or on either side of this support, which is then at least partially transparent.

As mentioned above, the first and second compositions can be juxtaposed and do not overlap, in particular in the case of mark printing.

The security structure may include an opaque perforated layer and the first and second compositions may be located respectively on either side of this layer. The perforated opaque layer can be defined for example by at least one layer of locally demetallized metal or by a selective metallization or by a opacifying printing which is not necessarily metallic, for example comprising a black pigment or TiO ₂ .

The presence of the perforated opaque layer can allow, in the aperture (s), the light emitted by the second composition to be added at least partially to the light emitted by the first, therefore to observe a light under the predefined illuminant. resultant function of the luminescence colors present. Furthermore, the openings of the perforated opaque layer can also form patterns, which further enhances the safety of the structure.

In an exemplary embodiment, the security structure comprises a perforated opaque layer, with on one side thereof the first and second respectively fluorescent and phosphorescent compositions, and on the other side of this perforated opaque layer at least another luminescent, phosphorescent or fluorescent composition, preferably third and fourth respectively fluorescent and phosphorescent compositions.

Numerous arrangements of the first, second, third and fourth compositions are possible, in particular in order to play on the nature of the compositions which are superimposed through the openings of the openwork opaque layer.

In particular, in an exemplary embodiment, the first and third compositions are shifted when the structure is observed from the first face. The second composition is also offset from the fourth. The first and third compositions can be superimposed at least partially with an openwork. The same can be done with the second and fourth compositions. The first and fourth compositions can be superimposed at the level of an openwork. The same can be true of the second and third compositions. The first and second compositions can be juxtaposed, without being superimposed; the same applies, for example, to the third and fourth compositions.

The first and third compositions can be the same or different, as can the second and fourth compositions. When the first and third compositions are different, as well as the second and fourth compositions, the first composition can emit by luminescence, in one example, the color of the fourth and the second composition that of the third.

In an exemplary embodiment, the structure comprises two openwork opaque layers, these opaque layers possibly being perforated differently. The first composition can be located between the two openwork opaque layers and one of the openwork opaque layers can be located between the two compositions. Furthermore, the openings of the perforated opaque layer can also form patterns, which further enhances the safety of the structure.

Alternatively or in combination with an opaque perforated layer, the security structure may include at least one element forming a barrier to ultraviolet (UV) radiation, in particular a layer forming a barrier to UV radiation. Such a barrier layer can for example be applied by printing and / or by coating. The barrier layer can be applied partially or totally to the support and / or to the fluorescent composition and / or to the phosphorescent composition.

By "barrier" is meant that the element or the layer prevents the passage of UV radiation for at least a certain range of wavelength values. The "barrier" function can make it possible to avoid the effects of subtractive combination of fluorescence and phosphorescence.

The barrier layer can for example be applied by a conventional printing process, for example flexography, screen printing, inkjet or digital printing, by curtain coating, by roller application, by spraying or painting, among others.

The element and / or the barrier layer can be applied in the form of a pattern, for example a symbol, an alphanumeric character, a logo, among others. The pattern can be reproduced identically on the security document comprising the security structure.

The support of the security structure can incorporate at least one UV radiation barrier element and / or at least one UV radiation barrier layer can be applied to at least one of the faces of the support and / or to at least one. fluorescent and phosphorescent compositions. In particular, a first barrier layer to UV radiation can be applied to the fluorescent composition and a second barrier layer to UV radiation can be applied to the phosphorescent composition, the first and second layers comprising in particular elements barrier to UV radiation which do not overlap. not.

The layer and / or the barrier element to UV radiation can make it possible to prevent the passage of UV radiation whose wavelength is less than or equal to 400 nm.

The layer and / or the barrier element can comprise a binder chosen as a function of the support, for example nitrocellulose, PVC, acrylate, among others. The layer and / or the barrier element can comprise an additive absorbing UV radiation, for example a phosphite, triazine, benzotriazole, an ether-amine, for example Tinuvin® marketed by CIBA or Chisorb® marketed by DOUBLE BOND, among others.

At least one of the compositions can be introduced into the security structure other than by printing. For example, at least one of the layers of the security structure is a film of extruded thermoplastic material or a coating, which incorporates a pigment or a fluorescent or phosphorescent dye, or even which consists of a fluorescent or phosphorescent compound.

The term “composition” should thus be understood broadly as encompassing both a solid film and a deposit which has solidified, such as an ink deposit for example or a varnish.

The fluorescent composition and / or the phosphorescent composition may comprise a mixture of iridescent substances exhibiting an interference effect.

Among the iridescent substances which can be used according to the invention, mention may in particular be made of mother-of-pearl extracts, lead salts and micas. In this respect, the preferred substances are micas, because mother-of-pearl extracts are very expensive, and lead salts, because of their toxicity, require compliance with very strict hygiene and safety rules. Among the iridescent substances which are suitable, micas coated with at least one metal oxide are recommended, and in particular the products marketed by the company Merck AG under the name IRIODINE®, these products being micas coated with T _i O ₂ with, where appropriate, at least one other metal oxide.

The security structure may be in the form of a security element intended to be integrated into any security document, in particular a paper document comprising natural and / or synthetic fibers, in particular cellulose fibers.

The security structure can advantageously be in the form of a security thread or of a patch or of a security film. Alternatively, the security structure may merge with the security document, when the latter comprises a substrate on which the first and second compositions are applied directly, for example by printing, on the substrate of the entire document or in a strip. In the case of a security structure in the form of a wire, the latter can be integrated into a paper mass during the formation of the sheet, for example in a machine with a round shape or with a flat table. In this case, the sheet can be formed so as to be equipped with windows, constituting openings allowing the security thread or the patch to appear at least partially.

Another subject of the invention is a security document incorporating a security structure as defined above.

The security structure may be observable from both sides of the document or from only one of the sides, depending on the variants. The security structure may possibly merge with the document, for example when the latter comprises a paper or other substrate which is printed with the first and second compositions.

The security document can be chosen from identity documents and valuable documents, for example banknotes, tickets for shows or sporting events, checks, identity cards, passports, tickets. transport, among others.

Preferably, each of the fluorescent and phosphorescent compositions spans less than the full extent of one side of the document.

The fluorescent composition preferably emits a red, green, blue or yellow color under UV illuminant at 365 nm. The same is true of the phosphorescent composition.

The security document, or the security structure that it includes, may include one or more additional security elements as defined below.

Among the additional security elements, some are detectable by eye, in daylight or in artificial light, without using a particular device. These security elements include, for example, colored fibers or planchettes, fully or partially printed or metallized threads. These security elements are said to be first level.

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

Other types of additional security elements require a more sophisticated detection device for their detection. 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 the document, if necessary. These security elements include, 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.

The additional security element (s) present within the security document, or the security structure that it comprises, may have first, second or third level security characteristics.

The phosphorescent composition may contain at least one phosphorescent compound chosen from zinc sulphide ZN S DOPE and a mixture of inorganic salts, for example produced by the company GLOWBUG.

The fluorescent composition may contain at least one fluorescent compound chosen from a copolymer of acrylic styrene from the company ARJOWIGGINS and a magnesium doped with zinc sulfide from the company GLOWBUG.

A subject of the invention is also a method of manufacturing a security structure as defined above, in which first and second compositions, respectively fluorescent and phosphorescent, are deposited on a support, in particular under UV illuminant at 365 nm, the deposition taking place in such a way that the two compositions are simultaneously excitable from the same face of the structure. The deposition of the compositions can be carried out by printing, in particular a marked printing of one of the compositions with respect to the other. The compositions can be deposited on one side of the structure or as a variant on both sides of the structure. The phosphorescent and fluorescent compositions for example each have a thickness of between 1 and 6 μm.

A further subject of the invention is a method for manufacturing a security document in which a security structure according to the invention, as defined above, is incorporated into a paper substrate.

• on éclaire le document par l'illuminant défini,
• on vérifie l'authenticité du document au moyen du motif qui, à l'extinction de l'éclairage par l'illuminant prédéfini, apparait ou disparait ou qui change d'apparence en passant d'un motif positif ou négatif ou d'une couleur à une autre.

A further subject of the invention is a method for authenticating a document comprising a security structure as defined above, one of the first and second compositions of the document security structure forming at least one pattern, the process comprising the following steps:

• the document is illuminated by the defined illuminant,
• the authenticity of the document is verified by means of the pattern which, when the lighting is switched off by the predefined illuminant, appears or disappears or which changes appearance by changing from a positive or negative pattern or a color to another.

In an exemplary implementation, one face of the structure is observed under UV illuminant and after extinction of the UV illuminant, and information relating to the authenticity of the document is deduced from the comparison of the observations. This comparison can be carried out automatically within a device responsible for this comparison, if necessary. In particular, under UV illuminant, both the light emitted by the fluorescent composition and the light emitted by the phosphorescent composition and / or an additive combination of the latter are observed. After extinction of the UV illuminant, only the light emitted by the phosphorescent composition is observable. According to the combinations described above, it is thus possible to make the patterns formed by the first and / or second compositions appear / disappear which, by comparison between the presence of UV illuminant and after its extinction, makes it possible to authenticate the document.

• la figure 1 représente isolément, de façon schématique et partielle, en vue de face, un exemple d'une structure de sécurité.
• la figure 2 est une section longitudinale, partielle et schématique, de la structure de sécurité,
• les figures 3a et 3b représentent la structure de la figure 1, respectivement lorsqu'observée sous UV et lorsque cesse l'illumination UV,
• les figures 3c et 3d sont des vues analogues aux figures 3a et 3b, d'une variante de réalisation,
• les figures 4a et 4b sont des vues analogues aux figures 3a et 3b, d'une autre variante de réalisation,
• les figures 5 à 12 sont des vues analogues à la figure 2, de variantes de réalisation,
• la figure 13 représente un exemple d'un document de sécurité incorporant une structure de sécurité, et
• la figure 14 est une vue analogue à la figure 2 d'une variante de réalisation.

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

• the figure 1 shows separately, schematically and partially, in front view, an example of a safety structure.
• the figure 2 is a longitudinal section, partial and schematic, of the safety structure,
• the figures 3a and 3b represent the structure of the figure 1 , respectively when observed under UV and when UV illumination ceases,
• the figures 3c and 3d are views analogous to figures 3a and 3b , an alternative embodiment,
• the figures 4a and 4b are views analogous to figures 3a and 3b , of another variant embodiment,
• the figures 5 to 12 are views analogous to figure 2 , variant embodiments,
• the figure 13 represents an example of a security document incorporating a security structure, and
• the figure 14 is a view analogous to figure 2 an alternative embodiment.

We represented at the figure 1 an example of a security structure 10.

In the example of figure 1 , the security structure 10 is in the form of a security thread, the width l of which is for example between 0.5 mm and 25 mm, this thread being intended for example to be incorporated as a strip in a document of security, then extending from one edge of this document to the opposite edge, the incorporation being able to take place in window (s) or on the surface.

The thickness of the structure 10 is generally, for example between 12 and 45 μm.

The invention is not limited to a security structure in the form of a wire and what follows applies to any security structure in a form other than a wire, for example in patch or foil, or even in a security structure formed by the document itself.

The structure 10 comprises a support 11 which is for example with a single-layer or multilayer structure, the support 11 preferably comprising at least one layer of a thermoplastic material, preferably transparent, for example of PET.

The structure 10 may include thermo-adhesive varnishes or other surface coatings intended to improve its adhesion to the substrate, in particular fibrous, in which or to which it is fixed. The structure 10 may include elements of additional security such as magnetic or other elements, chosen from those of the first, second or third levels mentioned above.

The support 11 carries on one face 14 a phosphorescent composition 12 covered with a fluorescent composition 13.

The phosphorescent composition 12 is for example deposited by printing on the support 11 and forms one or more patterns 15, for example in positive writing as visible on the figure 3b .

The fluorescent composition 13 is for example deposited in the form of a solid which covers the entire face 14 of the support 11 and the patterns 15 defined by the phosphorescent composition 12. The fluorescent composition 13 is for example deposited by printing.

The phosphorescent 12 and fluorescent 13 compositions can be chosen so as to emit by luminescence under UV excitation, at 365 mm, the same color substantially at the same intensity, such that under UV lighting, the structure 10 appears on the side of the face. 14 of the support of substantially uniform appearance, as shown in figure 3a , without the possibility for the observer to distinguish the patterns 15 formed with the phosphorescent composition 12.

After extinction of the UV illuminant, the layer of fluorescent composition 13 ceases to emit and the patterns 15 defined by the phosphorescent composition 12 appear, as illustrated in figure 3b . The time during which the units 15 formed with the composition 12 remain visible depends on the duration of the remanence of the phosphorescent composition. Preferably, this duration of remanence is greater than or equal to 3 seconds.

It is also possible to use phosphorescent 12 and fluorescent 13 compositions which emit different colors by luminescence. In this case, under UV lighting at 365 mm, the two compositions 12 and 13 emit different lights which, by additive synthesis where the compositions are superimposed, give patterns 15 which appear of a first color, on a colored background 16 which appears of another color, which is that of fluorescence of the fluorescent composition 13 in the example illustrated in figure 3c .

For example, when using a fluorescent composition 13 which fluoresces blue light and a phosphorescent composition 12 which emits by fluorescence. phosphorescence of yellow light, under UV lighting the patterns 15 appear in white, by additive synthesis where the compositions are superimposed, while the background 16 appears in blue. When the UV excitation is turned off, the patterns 15 appear in yellow for the duration of the persistence of the phosphorescent composition 12, as illustrated in 3d figure .

In the example of figures 3a and 3b , the impression made with the phosphorescent composition 12 is a positive writing impression.

It is possible, without departing from the scope of the present invention, to produce this printing in negative writing, as illustrated in figures 4a and 4b . The term "writing" should not be understood in a limiting sense and encompasses images and designs in addition to the usual writing characters. Under UV excitation, the security structure 10 appears uniform in color when using phosphorescent and fluorescent compositions which luminescent substantially the same color with the same intensity. On the figure 4b , it is seen that after extinction of the UV source, the negative writing defined by the phosphorescent composition 12 appears.

It is also possible to use phosphorescent and fluorescent compositions which emit the same color, but at different intensities. In this case, under UV and assuming that the phosphorescent composition defines positive patterns, the pattern (s) will appear with a different contrast from the background compared to the absence of UV, due to the addition of the intensities luminous of the phosphorescent composition and of the fluorescent composition. After extinction of the UV source, only the units defined by the phosphorescent composition appear positive.

In one variant, a pattern defined by the phosphorescent composition is superimposed on a solid area of fluorescent composition, the phosphorescent composition emitting with a lower intensity than the fluorescent composition.

In the alternative embodiment of the figure 5 , the fluorescent composition 13 is deposited in the form of a solid on the face 14 of the support 11, while the phosphorescent composition 12 is deposited in the form of patterns in positive or negative writing, depending on the variants. The term “flat” should be understood to mean a homogeneous deposit of sufficient extent to extend around the pattern at least.

In the alternative embodiment of the figure 6 , the fluorescent composition 13 is deposited on the face 14 of the support 11 in the form of patterns, in positive writing or negative, and the phosphorescent composition 12 is deposited in the form of a solid which covers the fluorescent composition 13.

In the example of figure 7 , the phosphorescent composition 12 is deposited in the form of a solid on the face 14 of the support 11, while the fluorescent composition 13 is deposited so as to define patterns in positive or negative writing, on the phosphorescent composition 12.

In the examples described above with reference to figures 2 and 5 to 7 , the phosphorescent 12 and fluorescent 13 compositions are located on the same side of the support 11.

It is possible, without departing from the scope of the present invention, to place the phosphorescent 12 and fluorescent 13 compositions respectively on either side of the support 11, the fluorescent composition 13 being for example deposited on the face 14 and the phosphorescent composition 12 on the surface. opposite face 17, as shown in figure 8 , the support 11 being at least partially transparent where the compositions 12 and 13 are superimposed and / or where it is superimposed with the composition deposited on the face 17.

On the figure 9 , an alternative embodiment has been illustrated in which the phosphorescent 12 and fluorescent 13 compositions are placed juxtaposed and marked on the same side of the support 11. In this exemplary embodiment, there is no superposition of the compositions 12. and 13.

In the alternative embodiment of the figure 10 , the compositions 12 and 13 are deposited respectively on either side of the support 11, the face 14 of the support 11 being for example printed with the fluorescent composition 13 and the opposite face 17 with the phosphorescent composition 12. This printing can be done. perform at the mark as shown.

In the variants of figures 8 and 10 , the support 11 is at least partially transparent, so as to make it possible to excite the luminescence from an illumination of the structure 10 on the same side of the latter, and to observe the emitted light from this same side by luminescence both by the fluorescent composition 13 and by the phosphorescent composition 12.

The support 11 can be only partially transparent, which can include opaque zones 18, for example metallizations, and openings 19, as illustrated in figure 11 .

The compositions 12 and 13 can be printed with the mark on each of the faces of the support 11, so that on each of the faces of the structure one can observe a juxtaposition of zones formed respectively by the phosphorescent composition 12 and by the fluorescent composition 13. Zones are thus observed where the compositions 12 or 13 located on either side of the support 11 are both superimposed at least partially with the same opaque zone 18 of the support 11, which is the case with zones S0, S3, S6. , S9 on the figure 11 , and zones or phosphorescent compositions 13 respectively located on either side of support 11 are superimposed with openings 19, which is the case with zones S1, S7. There are also areas where the fluorescent compositions 13 respectively located on either side of the support 11 are superimposed with openings 19, which is the case for areas S4 and S10. There are also areas where the fluorescent 12 and phosphorescent 13 compositions respectively located on either side of the support 11 are superimposed, which is the case with areas S2, S5 and S8.

Depending on the nature of the fluorescent and phosphorescent compositions, different effects can be observed. Hereinafter, two sides A and B for illuminating the structure and observing it are distinguished, side A being turned towards face 14 of support 11 and side B on the opposite side.

Example 1: Lighting under UV maintained with the phosphorescent composition 12 which emits a blue light and the fluorescent composition 13 a yellow light

Observer UV lighting Visual rendering So S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 AT AT blue blue yellow yellow yellow blue blue blue yellow yellow yellow B B yellow blue blue blue yellow yellow yellow blue blue blue yellow AT B zero blue purple zero yellow White zero blue purple zero yellow B AT zero blue White zero yellow purple zero blue White zero yellow

When the lighting is maintained on the side of face B, which is observed from face A, we see violet at the level of zone S2, which corresponds to the emission of blue light under the fluorescent composition which emits in yellow.

When the lighting is maintained on the side of face A, which is observed from face B, white is seen at the level of zone S8, which corresponds to the emission of yellow light under the layer of phosphorescent composition which emits in blue.

Example 2: After extinction of the UV lighting with the phosphorescent composition 12 which emits in yellow and the fluorescent composition 13 in blue

Observer After extinguishing UV lighting Visual rendering So S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 AT AT zero zero yellow yellow yellow zero zero zero yellow yellow yellow B B yellow zero zero zero yellow yellow yellow zero zero zero yellow AT B zero zero yellow zero intense yellow yellow zero zero yellow zero intense yellow B AT zero zero yellow zero intense yellow yellow zero zero yellow zero intense yellow

Example 3: After extinction of the UV lighting with the side of face A, the phosphorescent composition emits in yellow and the fluorescent composition emits in blue and on the side of the face B the phosphorescent composition emits in blue and the fluorescent composition emits in yellow

Observer After switching off UV lighting Visual rendering So S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 AT AT zero zero yellow yellow yellow zero zero zero yellow yellow yellow B B zero blue blue blue zero zero zero blue blue blue zero AT B zero blue purple zero yellow zero zero blue purple zero yellow B AT zero blue White zero yellow zero zero blue White zero yellow

The figure 14 represents an alternative embodiment of a security structure 10 according to the invention.

In this example, the support 11 is completely transparent and comprises on each of its opposite faces elements 20 forming a barrier to ultraviolet (UV) radiation, applied for example in the form of layers respectively on the surface. fluorescent composition 13 and on phosphorescent composition 12. In particular, the barrier elements 20 can be placed on either side of the support 11 without being superimposed on each other.

Preferably, the elements 20 forming a barrier to ultraviolet radiation are transparent to visible radiation so that the pattern they form is visible only under a predefined excitation and invisible under visible radiation, which further adds to the safety of the light. structure.

The barrier elements 20 can correspond to prints and / or coatings made on the support 11.

The barrier elements 20 can form a pattern, which can appear under a predefined excitation to allow authentication of the security structure 10.

The formation of the barrier elements 20 on the support 11, in particular by printing and / or coating, can be carried out after the manufacture of the support 11 coated with fluorescent 13 and phosphorescent 12 compositions, thus making it possible to personalize the security structure 10, for example under in the form of a security thread, with the aid of the barrier elements 20 arranged in the form of patterns.

The barrier elements 20 can be printed at the mark on each of the faces of the support 11, coated respectively with the fluorescent composition 13 and the phosphorescent composition 12. Areas are thus observed where the compositions 12 and 13 located on either side of the support 11 are superimposed on one another, which is the case with zones S1 and S3, and zones where compositions 12 and 13 located on either side of support 11 are both at least partially superimposed with a same barrier element 20 , which is the case with areas S0, S2 and S4.

Depending on the nature of the fluorescent and phosphorescent compositions, different effects can be observed. Hereinafter, two sides A and B for illuminating the structure and observing it are distinguished, side A being turned towards face 14 of support 11 and side B on the opposite side.

Example 4: Lighting under UV maintained with the phosphorescent composition 12 which emits a blue light and the fluorescent composition 13 a yellow light

Observer UV lighting Visual rendering S0 S1 S2 S3 S4 AT AT zero yellow yellow yellow zero B B blue White zero White blue AT B zero White zero White zero B AT zero blue zero blue zero

When the lighting is maintained on the side of face A that we observe from face B, or when the lighting is maintained on the side of face B that we observe from face A, we see white in the level of areas S1 and S3, which corresponds to an emission of yellow (or blue) light under the layer of phosphorescent (or fluorescent) composition which emits blue (or yellow).

The embodiments described above can be combined with one another. In particular, the support 11 of the figure 14 may include opaque areas, as described above, for example in the form of metallizations, and / or UV radiation barrier elements arranged for example between openings 19 as described above.

In particular, a support 11 comprising barrier elements 20 can be produced using two films, in particular made of polyester, the first film serving as a support for the printing and / or coating of barrier elements 20, which constitute a second film on which the fluorescent and / or phosphorescent compositions are deposited.

As a variant, it is provided according to the invention that the security structure comprises only a first fluorescent composition and a second phosphorescent composition in the form of a solid, respectively arranged on either side of the perforated support.

One represented on the figure 12 an alternative embodiment in which the structure 10 comprises two transparent layers 11a and 11b.

On each transparent layer 11a and 11b, a partially opaque layer 18a, 19a and 18b and 19b has been deposited. An adhesive 25 ensures the cohesion of the layers 11a, 11b and the perforated opaque layers.

When the structure 10 is observed under UV illuminant from the face 14 of the layer 11a, by illuminating the structure from this face, the lights emitted by luminescence by the compositions 12 and 13 are added where the openings 19b allow the light emitted by the fluorescent composition 13 to reach the face 14, while where this light is blocked by the opaque zones 18b, the patterns formed by the openings 19a are only observable with the light produced by the fluorescent composition 13.

We represented at the figure 13 an example of a security document 30 incorporating a security structure 10 in accordance with the invention. This is in the form of a security thread incorporated into windows, and extending from one edge of the document to the other.

Of course, the invention is not limited to the embodiments which have just been described. The particular embodiments of the examples which have just been described can in particular be combined with one another within variants not illustrated.

The expression “comprising a” should be understood as being synonymous with “comprising at least one”, unless specified to the contrary.

Claims (15)

1. Security structure (10) comprising:

   - at least one first fluorescent composition (13),

   - at least one second phosphorescent composition (12), the first and second compositions being able to be excited simultaneously by a predefined illuminant from one and the same first face (14) of the structure,

   the security structure (10) being in the form of a security thread, a security film or a patch, and
   the first fluorescent composition being superposed, at least partially, on the second phosphorescent composition,
   and/or
   the first and second compositions being applied in register on the security structure,
   a support of the security structure incorporating at least one barrier element to UV radiation and/or at least one barrier layer to UV radiation being applied on at least one of the fluorescent and phosphorescent compositions.
2. Security structure (10) comprising:

   - at least one first fluorescent composition (13),

   - at least one second phosphorescent composition (12), the first and second compositions being able to be excited simultaneously by a predefined illuminant from one and the same first face (14) of the structure,

   the security structure (10) being in the form of a security thread, a security film or a patch, and
   the first fluorescent composition being superposed, at least partially, on the second phosphorescent composition,
   and/or
   the first and second compositions being applied in register on the security structure,
   the security structure comprising an apertured opaque layer (18, 19), the first (13) and second (12) compositions being located respectively on either side of this layer or the first and second compositions being located on one side of this layer and at least one other phosphorescent or fluorescent composition being located on the other side of this layer.
3. Security structure according to either of the preceding claims, in which the lights emitted, under illumination by the predefined illuminant, by the fluorescent composition (13) and by the phosphorescent composition (12) can be observed from one and the same face of the structure (10).
4. Security structure according to any one of the preceding claims, one of the first (13) and second (12) compositions forming a flat tint area which is superposed on the other of the first and second compositions, the other of the first and second compositions forming at least one pattern (15).
5. Security structure according to any one of the preceding claims, in which one of the first (13) and second (12) compositions forms at least one pattern which, on extinguishing the illumination by the predefined illuminant, appears or disappears, or which changes appearance by passing from a positive pattern to a negative pattern or from one colour to another.
6. Security structure according to any one of the preceding claims, the first (13) and second (12) compositions being deposited by printing or by deposition of a varnish.
7. Security structure according to any one of the preceding claims, the first (13) and second (12) compositions emitting by luminescence one and the same colour with preferably the same intensity.
8. Security structure according to Claim 7, the first (13) and second (12) compositions emitting by luminescence one and the same colour with different intensities, the phosphorescent composition (12) being preferably in this case on top of the fluorescent composition (13).
9. Security structure according to one of Claims 1 to 6, the first fluorescent composition (13) emitting, under illumination by the predefined illuminant, a visible light of a first colour, the second phosphorescent composition (12) emitting, under illumination by the predefined illuminant, a visible light of a second colour different from the first colour, and at least one zone of superposition of the first and second fluorescent and phosphorescent compositions emitting, under illumination by the predefined illuminant, a visible light of a third colour resulting from the additive synthesis of the first and second colours.
10. Security structure according to Claim 2, the security structure comprising two apertured opaque layers (18, 19), the opaque layers being preferably apertured differently, one of the first (13) and second (12) compositions being located between the two apertured opaque layers and one (18b, 19b) of the apertured opaque layers being located between the two compositions (12, 13) .
11. Security structure according to one of Claims 1 to 9, the security structure comprising an apertured opaque layer (18, 19) with, on one side of this layer, the respectively fluorescent and phosphorescent first (13) and second (12) compositions, and, on the other side of this apertured opaque layer, respectively fluorescent or phosphorescent third and fourth compositions, preferably with a superposition of at least one aperture with, on the one hand, one of the first and second compositions and, on the other hand, one of the third and fourth compositions,
    the first and third compositions preferably being offset when the structure is observed from the first face (14).
12. Security structure according to any one of the preceding claims, the barrier elements to UV radiation comprising an additive that absorbs UV radiation chosen from a phosphite, triazine, benzotriazole and an ether amine.
13. Security structure according to the preceding claim, comprising a transparent support (11), the support (11) comprising on each of its opposite faces barrier elements (20) to UV radiation applied respectively to the fluorescent composition (13) and to the phosphorescent composition (12), the barrier elements preferably being applied after the manufacture of the support (11) coated with the fluorescent (13) and phosphorescent (12) compositions.
14. Security document incorporating a security structure according to any one of Claims 1 to 12.
15. Process for authenticating a security document (30) according to the preceding claim, one of the first (13) and second (12) compositions of the security structure (10) of the document forming at least one pattern, the process comprising the following steps:

    - illuminating the document with the predefined illuminant,

    - verifying the authenticity of the document by means of the pattern which, on extinguishing the illumination by the predefined illuminant, appears or disappears, or which changes appearance by passing from a positive pattern to a negative pattern or from one colour to another.

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