Security structure including phosphorescent and fluorescent compositions

Abstract

The present invention relates to a security structure (10), comprising at least one first fluorescent composition (13) and at least one second phosphorescent composition (12), the first and second compositions being simultaneously excitable by a predefined illuminant from a single first surface (14) of the structure, the security structure (10) being provided in the form of a security thread, a security film, or a patch, wherein the first fluorescent composition is at least partially stacked on the second phosphorescent composition and/or the first and second compositions are used for the reference marking on the security structure.

Claims

1. A security structure comprising: at least one first fluorescent composition, at least one second phosphorescent composition, the first and second compositions being able to be excited simultaneously by a predefined illuminant from one and the same first face of the structure, the first fluorescent and second phosphorescent compositions being deposited on a support of the security structure, the support having first and second sides the security structure being in the form of a security thread, a security film or a patch, and the first fluorescent composition being superposed, at least partially, with the second phosphorescent composition and/or the first and second compositions being applied in register on the security structure, and the security structure comprising, on each of the first and second sides of the support, a barrier layer applied partially to the support of the security structure and/or to the first fluorescent composition and/or second phosphorescent composition, the first fluorescent and second phosphorescent composition being situated between the barrier layers in the thickness direction of the security structure, the barrier layers having a property of acting as a barrier to ultraviolet radiation if exposed thereto, the barrier layers being transparent to visible radiation, the barrier layers comprising an additive that absorbs UV radiation chosen from a phosphite, a triazine, a benzotriazole and an ether amine.

2. The security structure as claimed in claim 1, wherein lights emitted, under lighting by the predefined illuminant, by the fluorescent composition and by the phosphorescent composition can be observed from one and the same face of the structure.

3. The security structure as claimed in claim 2, the first and second compositions emitting by luminescence one and the same color.

4. The security structure as claimed in claim 3, the first and second compositions emitting by luminescence one and the same color with substantially the same intensity.

5. The security structure as claimed in claim 3, the first and second compositions emitting by luminescence one and the same color with different intensities.

6. The security structure as claimed in claim 5, the phosphorescent composition being on top of the fluorescent composition.

7. The security structure as claimed in claim 1, one of the first and second 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.

8. The security structure as claimed in claim 1, wherein one of the first and second compositions forms at least one pattern which, on extinguishing the lighting by the predefined illuminant, appears or disappears, or which changes appearance while passing from a positive pattern to a negative pattern or from one color to another.

9. The security structure as claimed in claim 1, the first and second compositions being deposited by printing or by deposition of a lacquer.

10. The security structure as claimed in claim 1, the first fluorescent composition emitting, under lighting by the predefined illuminant, a visible light of a first color, the second phosphorescent composition emitting, under lighting by the predefined illuminant, a visible light of a second color that is different than the first color, and at least one zone of superposition of the first and second fluorescent and phosphorescent compositions emitting, under lighting by the predefined illuminant, a visible light of a third color resulting from the additive synthesis of the first and second colors.

11. The security structure as claimed in claim 1, the first composition being juxtaposed with the second composition.

12. The security structure as claimed in claim 1, a support of the security structure incorporating at least one barrier element.

13. The security structure as claimed in claim 1, the barrier layer comprising a binder chosen from nitrocellulose, PVC and acrylate.

14. The security structure as claimed in claim 1, the first fluorescent and second phosphorescent compositions being deposited on one and the other side of the support, the barrier layers being applied respectively on the first fluorescent and second phosphorescent compositions.

15. A security structure comprising: at least one first fluorescent composition, at least one second phosphorescent composition, the first and second compositions being able to be excited simultaneously by a predefined illuminant from one and the same first face of the structure, the security structure being in the form of a security thread, a security film or a patch, the first fluorescent composition being superposed, at least partially, with the second phosphorescent composition and/or the first and second compositions being applied in register on the security structure, and the security structure further comprising an apertured opaque layer having a first side and a second side, and the first and second compositions being located respectively on the first side and second side of the apertured opaque layer.

16. The security structure as claimed in claim 15, the structure comprising a first apertured opaque layer and a second apertured opaque layer, the first apertured opaque layer being apertured differently than the second aperture opaque layer.

17. A security structure comprising: at least one first fluorescent composition, at least one second phosphorescent composition, the first and second compositions being able to be excited simultaneously by a predefined illuminant from one and the same first face of the structure, the security structure being in the form of a security thread, a security film or a patch, the first fluorescent composition being superposed, at least partially, with the second phosphorescent composition and/or the first and second compositions being applied in register on the security structure, and the security structure comprising two apertured opaque layers, the second composition being located between the two apertured opaque layers and one of the apertured opaque layers being located between the first composition and the second composition.

18. A security structure comprising: at least one first fluorescent composition, at least one second phosphorescent composition, the first and second compositions being able to be excited simultaneously by a predefined illuminant from one and the same first face of the structure, the security structure being in the form of a security thread, a security film or a patch, the first fluorescent composition being superposed, at least partially, with the second phosphorescent composition and/or the first and second compositions being applied in register on the security structure, and the security structure further comprising an apertured opaque layer having a first side and a second side, the first side of the apertured opaque layer comprising the first fluorescent composition and the second phosphorescent composition, the second side of the apertured opaque layer comprising a third fluorescent composition or fourth phosphorescent composition, at least one aperture of the aperture opaque layer comprising a superposition of one composition chosen from one of the first and second compositions and one composition chosen from one of the third and fourth compositions.

19. The security structure as claimed in claim 18, the first and third compositions being offset when the structure is observed from the first face (14).

20. A security document incorporating a security structure as claimed in claim 1.

21. A security document incorporating a security structure comprising: at least one first fluorescent composition, at least one second phosphorescent composition, the first and second compositions being able to be excited simultaneously by a predefined illuminant from one and the same first face of the structure, the security document comprising a paper substrate on which the first and second compositions are applied directly, and the first fluorescent composition being superposed, at least partially, with the second phosphorescent composition, and/or the first and second compositions being applied in register on the security structure, and the security structure comprising, on each side of the paper substrate, a barrier layer having a property of acting as a barrier to ultraviolet radiation if exposed thereto, the first fluorescent and second phosphorescent compositions being situated between the barrier layers in the thickness direction of the security structure, the barrier layers being transparent to visible radiation, the barrier layers being applied in the form of a pattern, the barrier layers comprising an additive that absorbs UV radiation chosen from a phosphite, a triazine, a benzotriazole and an ether amine.

22. A process for authenticating a security document as claimed in claim 21, one of the first and second compositions of the security structure of the document forming at least one pattern, the process comprising the following steps: lighting the document with the predefined illuminant, verifying the authenticity of the document by using the pattern which, on extinguishing the lighting by the predefined illuminant, appears or disappears, or which changes appearance while passing from a positive pattern to a negative pattern or from one color to another.

Description

(1) The invention will be better understood on reading the detailed description which follows, of non-limiting exemplary embodiments thereof, and examining the appended drawings, in which:

(2) FIG. 1 represents, in isolation, schematically and partially, as a front view, an example of a security structure according to the invention,

(3) FIG. 2 is a partial and schematic longitudinal section of the security structure,

(4) FIGS. 3a and 3b represent the structure from FIG. 1, respectively when observed under UV and when the UV illumination ceases,

(5) FIGS. 3c and 3d are views similar to FIGS. 3a and 3b, of an embodiment variant,

(6) FIGS. 4a and 4b are views similar to FIGS. 3a and 3b, of another embodiment variant,

(7) FIGS. 5 to 12 are views similar to FIG. 2, of embodiment variants,

(8) FIG. 13 represents an example of a security document incorporating a security structure according to the invention, and

(9) FIG. 14 is a view similar to FIG. 2, of an embodiment variant.

(10) Represented in FIG. 1 is an example of a security structure 10, produced in accordance with the invention.

(11) In the example from FIG. 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 security document, extending then from one edge of this document to the opposite edge, it being possible for the incorporation to be carried out as window(s) or at the surface.

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

(13) The invention is not limited to a security structure in thread form and what follows applies to any security structure that is in a form other than a thread, for example as a patch or foil, or even to a security structure constituted by the document itself.

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

(15) The structure 10 may comprise thermo-adhesive lacquers or other surface coatings intended to improve its attachment to the substrate, especially fibrous substrate, to which or on which it is fastened. The structure 10 may comprise additional security elements, such as magnetic or other elements, chosen from those of the aforementioned first, second or third levels.

(16) The support 11 bears on a face 14 a phosphorescent composition 12 covered by a fluorescent composition 13.

(17) The phosphorescent composition 12 is for example deposited by printing onto the support 11 and forms one or more patterns 15, for example in positive writing as can be seen in FIG. 3b.

(18) The fluorescent composition 13 is for example deposited in the form of a flat tint area which covers the whole of the 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.

(19) The phosphorescent composition 12 and fluorescent composition 13 may be chosen so as to emit by luminescence under UV excitation, at 365 nm, one and the same color substantially at the same intensity, so that, under UV lighting, the structure 10 appears from the side of the face 14 of the support to have a substantially uniform appearance, as illustrated in FIG. 3a, with no possibility for the observer to discern the patterns 15 formed with the phosphorescent composition 12.

(20) After extinguishing the UV illuminant, the layer of fluorescent composition 13 stops emitting and the patterns 15 defined by the phosphorescent composition 12 are seen to appear, as illustrated in FIG. 3b. The duration for which the patterns 15 formed with the composition 12 remain visible depends on the afterglow time of the phosphorescent composition. Preferably, this afterglow time is greater than or equal to 3 seconds.

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

(22) For example, during the use of a fluorescent composition 13 which emits, by fluorescence, blue light and of a phosphorescent composition 12 which emits, by phosphorescence, yellow light, under UV lighting the patterns 15 appear white, by additive synthesis where the compositions are superposed, whereas the background 16 appears blue. When the UV excitation is extinguished, the patterns 15 appear yellow for the afterglow time of the phosphorescent composition 12, as illustrated in FIG. 3d.

(23) In the example from FIGS. 3a and 3b, the printing produced with the phosphorescent composition 12 is printing in positive writing.

(24) It is possible, without departing from the scope of the present invention, to carry out this printing in negative writing, as illustrated in FIGS. 4a and 4b. The term writing should not be understood with a limiting meaning and encompasses images and drawings in addition to standard script characters. Under UV excitation, the security structure 10 appears as a uniform color in the case of the use of phosphorescent and fluorescent compositions that emit, by luminescence, substantially the same color with the same intensity. In FIG. 4b, it is seen that, after extinguishing the UV source, the negative writing defined by the phosphorescent composition 12 appears.

(25) 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 by assuming that the phosphorescent composition defines positive patterns, the pattern or patterns will appear with a different contrast relative to the background compared with the absence of UV, due to the addition of the light intensities of the phosphorescent composition and of the fluorescent composition. After extinguishing the UV source, only the patterns defined by the phosphorescent composition appear as positive patterns.

(26) In one variant, a pattern defined by the phosphorescent composition is superposed on a flat tint area of fluorescent composition, the phosphorescent composition emitting with a lesser intensity than the fluorescent composition.

(27) In the embodiment variant from FIG. 5, the fluorescent composition 13 is deposited in the form of a flat tint area on the face 14 of the support 11, while the phosphorescent composition 12 is deposited in the forms of patterns in positive or negative writing, depending on the variants. The expression flat tint area should be understood to mean a homogenous deposition of sufficient area to extend around the pattern at least.

(28) In the embodiment variant from FIG. 6, the fluorescent composition 13 is deposited on the face 14 of the support 11 in the form of patterns, in positive or negative writing, and the phosphorescent composition 12 is deposited in the form of a flat tint area which covers the fluorescent composition 13.

(29) In the example from FIG. 7, the phosphorescent composition 12 is deposited in the form of a flat tint area 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.

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

(31) It is possible, without departing from the scope of the present invention, to place the phosphorescent composition 12 and fluorescent composition 13 respectively on the first and second side of the support 11, the fluorescent composition 13 being, for example, deposited on the face 14 and the phosphorescent composition 12 on the opposite face 17, as illustrated in FIG. 8, the support 11 being at least partially transparent where the compositions 12 and 13 are superposed and/or where it is superposed with the composition deposited on the face 17.

(32) In FIG. 9, an embodiment variant has been illustrated in which the phosphorescent composition 12 and fluorescent composition 13 are positioned in a juxtaposed and registered manner on one and the same side of the support 11. In this exemplary embodiment, there is no superposition of the compositions 12 and 13.

(33) In the embodiment variant from FIG. 10, the compositions 12 and 13 are deposited respectively on the first and second 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 may take place in register, as illustrated.

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

(35) The support 11 may be only partially transparent, possibly comprising opaque zones 18, for example metallizations, and apertures 19, as illustrated in FIG. 11.

(36) The compositions 12 and 13 may be printed in register on each of the faces of the support 11, so that on each of the faces of the structure it is possible to 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 superposed at least partially with one and the same opaque zone 18 of the support 11, which is the case for zones S0, S3, S6, S9 in FIG. 11, and zones where the phosphorescent compositions 13 respectively located on the first and second side of the support 11 are superposed with apertures 19, which is the case for zones S1, S7. Zones are also observed where the fluorescent compositions 13 respectively located on the first and second side of the support 11 are superposed with apertures 19, which is the case for zones S4 and S10. Zones are also observed where the fluorescent composition 12 and phosphorescent composition 13 respectively located on the first and second side of the support 11 are superposed, which is the case for zones S2, S5 and S8.

(37) Depending on the nature of the fluorescent and phosphorescent compositions, it is possible to observe various effects. Distinguished below are two sides A and B of illumination of the structure and of observation thereof, the side A being turned toward the face 14 of the support 11 and the side B being 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

(38) TABLE-US-00001 Visual appearance Observer UV lighting So S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 A A blue blue yellow yellow yellow blue blue blue yellow yellow yellow B B yellow blue blue blue yellow yellow yellow blue blue blue yellow A B zero blue violet zero yellow white zero blue violet zero yellow B A zero blue white zero yellow violet zero blue white zero yellow

(39) When the lighting is maintained on the side of face B, which is observed from face A, violet is seen level with zone S2, which corresponds to the emission of blue light under the fluorescent composition which emits in the yellow range.

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

EXAMPLE 2

After Extinguishing the UV Lighting with the Phosphorescent Composition 12 which Emits in the Yellow Range and the Fluorescent Composition 13 in the Blue Range

(41) TABLE-US-00002 After extinguishing Visual appearance Observer UV lighting So S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 A A zero zero yellow yellow yellow zero zero zero yellow yellow yellow B B yellow zero zero zero yellow yellow yellow zero zero zero yellow A B zero zero yellow zero intense yellow yellow zero zero yellow zero intense yellow B A zero zero yellow zero intense yellow yellow zero zero yellow zero intense yellow

EXAMPLE 3

After Extinguishing the UV Lighting with, from the Side of Face A, the Phosphorescent Composition Emits in the Yellow Range and the Fluorescent Composition Emits in the Blue Range and, from the Side of Face B, the Phosphorescent Composition Emits in the Blue Range and the Fluorescent Composition Emits in the Yellow Range

(42) TABLE-US-00003 After extinguishing Visual appearance Observer UV lighting So S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 A A zero zero yellow yellow yellow zero zero zero yellow yellow yellow B B zero blue blue blue zero zero zero blue blue blue zero A B zero blue violet zero yellow zero zero blue violet zero yellow B A zero blue white zero yellow zero zero blue white zero yellow

(43) FIG. 14 represents another embodiment variant of a security structure 10 according to the invention.

(44) In this example, the support 11 is completely transparent and comprises, on each of its opposite faces, elements 20 that act as a barrier to ultraviolet (UV) radiation, applied for example in the form of layers respectively on the fluorescent composition 13 and on the phosphorescent composition 12. In particular, the barrier elements 20 may be placed on either side of the support 11 without being superposed on one another.

(45) Preferably, the elements 20 that act as a barrier to ultraviolet radiation are transparent to visible radiation so that the pattern that they form is visible only under a predefined excitation and invisible under visible radiation, which further adds to the security of the structure.

(46) The barrier elements 20 may correspond to printings and/or coatings produced on the support 11.

(47) The barrier elements 20 may form a pattern, which may appear under a predefined excitation in order to enable the authentication of the security structure 10.

(48) The formation of the barrier elements 20 on the support 11, especially by printing and/or coating, may be carried out after the manufacture of the support 11 coated with the fluorescent composition 13 and phosphorescent composition 12, thus making it possible to personalize the security structure 10, for example in the form of a security thread, with the aid of the barrier elements 20 positioned in the form of patterns.

(49) The barrier elements 20 may be printed in register on each of the faces of the support 11, which are respectively coated with the fluorescent composition 13 and with the phosphorescent composition 12. Zones are thus observed where the compositions 12 and 13 located on either side of the support 11 are superposed on one another, which is the case for zones S1 and S3, and zones where the compositions 12 and 13 located on either side of the support 11 are both at least partially superposed with one and the same barrier element 20, which is the case for zones S0, S2 and S4.

(50) Depending on the nature of the fluorescent and phosphorescent compositions, it is possible to observe various effects. Distinguished below are two sides A and B of illumination of the structure and of observation thereof, the side A being turned toward the face 14 of the support 11 and the side B being 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

(51) TABLE-US-00004 Visual appearance Observer UV lighting S0 S1 S2 S3 S4 A A zero yellow yellow yellow zero B B blue white zero white blue A B zero white zero white zero B A zero blue zero blue zero

(52) When the lighting is maintained on the side of face A which is observed from face B, or when the lighting is maintained on the side of face B which is observed from face A, white is seen level with zones S1 and S3, which corresponds to an emission of yellow (or blue) light under the layer of phosphorescent (or fluorescent) composition which emits in the blue (or yellow) range.

(53) The embodiments described previously may be combined with one another. In particular, the support 11 from FIG. 14 may comprise opaque zones, as described previously, for example in the form of metallizations, and/or barrier elements to UV radiation placed for example between apertures 19 as described previously.

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

(55) As a variant, provision is made according to the invention for the security structure to comprise only one first fluorescent composition and one second phosphorescent composition in the form of a flat tint area which are positioned respectively on the first and second side of the apertured support.

(56) Represented in FIG. 12 is an embodiment variant in which the structure 10 comprises two transparent layers 11a and 11b.

(57) Deposited on each transparent layer 11a and 11b is a partially opaque layer 18a, 19a and 18b and 19b. An adhesive 25 ensures the cohesion of the layers 11a, 11b and of the apertured opaque layers.

(58) When the structure 10 is observed under UV illuminant from the face 14 of the layer 11a, by lighting the structure from this face, the lights emitted, by luminescence, by the compositions 12 and 13 add together where the apertures 19b enable 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 apertures 19a can only be observed with the light produced by the fluorescent composition 13.

(59) Represented in FIG. 13 is an example of a security document 30 incorporating a security structure 10 in accordance with the invention. The latter is in the form of a security thread incorporated in windows, and extending from one edge to the other of the document.

(60) Of course, the invention is not limited to the exemplary embodiments which have just been described. It is possible, in particular, to combine together the distinctive embodiment features of the examples which have just been described within variants that are not illustrated.

(61) The expression comprising a should be understood as being synonymous with comprising at least one, unless otherwise specified.