FR3018085A1 - TACTILE SAFETY ELEMENT - Google Patents

Abstract

Security element (1) intended to be applied to or incorporated at least partially in a fibrous substrate, comprising - a support film (3) made of plastic material - at least one layer of a binder (2) at least partially covering the film carrier (3), - detectably detectable particles (4), at least partially incorporated in the binder layer.

Description

The present invention relates to the security elements used to secure documents such as banknotes and the articles thus secured. The invention is more particularly concerned with security elements having a touch-sensitive tactile effect and secure documents that include such elements.

Security features may have first, second, or third level security features. The security elements may be detectable by the bare, in daylight or artificial light or touch, without the use of a particular device, and consist for example of colored fibers or boards, security son printed or metallized totally or partially. These security elements are called first level. Other types of security elements may be detectable only with a relatively simple apparatus, such as a lamp emitting in the ultraviolet (UV) or infrared (IR). These security elements comprise, for example, fibers, boards, strips, wires or particles. These security elements may be visible to the naked or not, being for example luminescent under a lighting of a Wood lamp emitting at a wavelength of 365 nm. These security elements are said to be second level. Other types of security elements require for their detection a more sophisticated detection device. These security elements are for example capable of generating a specific signal when they are subjected, simultaneously or not, to one or more external excitation sources. The automatic detection of the signal makes it possible to authenticate, if necessary, the document. These security elements comprise, for example, tracers in the form of 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.

Security threads are top-level security features specific to paper-based documents, whose window insertion is visually quickly detected by the user. On the other hand, to the touch, the detection is more difficult, because the difference in roughness between the wire and the paper is small and the wire has a relatively small thickness. The authentication of documents thus secured by the visually impaired is not easy. Most touch-sensitive tactile sensing means for visually impaired persons are provided via printing, generally in the form of relief printing, in particular soft-sizing, embossing or removal of a lacquer allowance.

The application FR 2873134 describes a security element comprising a tactile recognition element in the form of a knitted structure placed in the mass of the support. The application FR 2907808 describes a security zone with tactile recognition, comprising particles detectable to the touch. The security zone may relax in the form of a band or a pattern such as an alphanumeric character. The safety zone contains iridescent pigments. The application WO 2010/044846 discloses a security element comprising tactile marks in the form of relief structures. The security element may be in the form of a security thread extending from one edge to the other of a fibrous substrate in which it is integrated. The wire can be incorporated into windows; in this case, the tactile marks may or may not be superimposed on the windows. Thus, some windows are superimposed with tactile marks, such as braille points, while others are not superimposed on any mark. In a variant, the security thread is completely integrated with the substrate, and the tactile marks are discerned through a certain thickness of paper. The marks may be formed by hot embossing a layer of a thermoplastic elastomer present on the surface of the wire. Alternatively, the marks are made using a resin crosslinked under UV or electron beam. There is a need to further improve the secure documents incorporating a touch-sensitive security element, in particular to achieve easily recognizable security including for visually impaired persons, and which is furthermore relatively simple to manufacture and incorporate into the paper. for a specialized company in the field. The invention thus relates to a security element intended to be applied to or incorporated at least partially in a fibrous substrate, comprising: a plastic support film, at least one layer of a binder covering at least partially the support film, - detectable particles that are at least partially incorporated into the binder layer. The detectable particles, and the binder which incorporates them at least partially, constitute a "tactile layer". By "plastic film" is excluded a fibrous layer comprising plastic fibers.

Compared to a detectable security tactilely provided by printing on the document substrate, the invention is based on a detectable security to the touch forming part of the security element embedded in the substrate and makes counterfeiting more difficult. The invention also makes it possible to guarantee a more durable tactile effect, since the security element is less exposed to wear than a security made directly on the fibrous substrate. In particular, the relief of the security element may be at least partially compensated by a certain thickness of the substrate. Preferably, the detectably detectable particles and the binder are present on an entire face of the support film, without discontinuity. Alternatively, the detectably detectable particles may be present in the form of patterns, for example simple geometrical shapes, and / or more sophisticated such as alphanumeric characters, or codes, on all or part of the surface of the support film. The patterns may extend discontinuously on at least one side of the support film. The patterns can relax at a non-zero distance from all the edges of the support.

More preferably, and especially when the security element is a security thread integrated in windows in a substrate, the detectably detectable particles are present in the form of spaced zones, especially spaced lines, so as to limit the creation, or even do not create, extra thicknesses at the bridges relaxing between the windows of the substrate.

The detectably detectable particles and the binder may be present on both sides of the support film, without discontinuity, in the form of patterns and / or as spaced apart areas. Fibrous Substrate The fibrous substrate comprises the fibers and adjuvants conventionally used in the papermaking field, in particular cellulose fibers. The substrate may comprise a mixture of long and short cellulosic fibers. The fibrous substrate comprises, for example, cellulosic fibers, in particular of wood, linen and / or cotton. Preferably, the substrate comprises cotton fibers.

The fibrous substrate may also comprise, at least in part, synthetic fibers. The substrate may comprise one or more fibrous layers (also called jets) assembled after formation, especially in the wet phase.

The fibrous substrate may be covered on at least one of its faces with a plastic protective coating. The substrate may comprise one or more safety structures obtained during manufacture, and the substrate may in particular comprise a watermark.

The fibrous layer (s) of the substrate may be made on a flat-bed or round-shaped paper machine, and the watermark (s) may be made partly wet according to the conventional methods known to those skilled in the art. At least one fibrous layer of the substrate, better the entire substrate, may have a basis weight (according to ISO 536) of between 60 and 120 g / m 2, preferably between 70 and 90 g / m 2. At least one fibrous layer of the substrate, better the entire substrate, may have a thickness (according to ISO 534) of between 60 and 150 μm, preferably between 70 and 120 μm, for example about 100 μm. In an exemplary implementation of the invention, at least one fibrous layer of the substrate comprises a window, in the form of a recess, passing through or not, made for example on a paper machine or off paper machine, for example by reduction de-watering, punching, laser cutting or jet Beau. The substrate may include printing, laser marking and / or magnetic coding.

In an exemplary implementation of the invention, the substrate is a sheet material comprising at least two fibrous juxtaposed juxtaposed one on the other, the first jet comprising at least one elongated zone of zero thickness and the second jet comprising at least one recess located opposite the at least one elongate zone of zero thickness of the first jet, this recess forming a window.

Support film The support film is preferably made of synthetic hydrocarbon polymer, for example a polyester or selected from polyethylene terephthalate-based polymers. The support film is most often transparent. The support film may carry information. For example, the support may comprise relief structures, for example made by embossing. The support film may also include printing, metallization / demetallization (eg Cleartext °), laser marking, and / or magnetic coding. The support film is preferably between 5 and 50 μm thick.

The support film is preferably of constant width, especially between 1 and 30 mm. The security element may comprise, for example on one side of the support film opposite to the binder layer, an opaque or semi-transparent layer with at least one aperture.

The opaque or semi-transparent layer is for example metallic. For example, the apertures are obtained by metallization / demetallization or printing, in the form of positive or negative writing, in particular of alphanumeric character and / or text. The support film may carry any first, second or third level security element.

Binder The binder comprises for example a polyvinyl alcohol (PVA) or a polyurethane (PU) or an acrylic polymer. It is preferably cFun elastomer, especially polyurethane or acrylic polymer. Preferably, the binder comprises a heat-sealing adhesive. This has the advantage that it can then have a dual function, on the one hand to maintain the detectable particles on the support film, on the other hand to improve the strength of the incorporation of the element to the substrate. The heat-sealing adhesive may include vinyl acetate, polyethylene, acrylic, or polyurethane. In particular, the heat-sealing adhesive may comprise ethylene vinyl acetate (EVA).

The security element may comprise, in particular elsewhere than in the detectably detectable particles, for example in the binder, at least one luminescent or magnetic compound and more generally any security element of second or third level. Preferably, the binder is deposited in amounts of between 3 and 15 g / m 2 per side, by dry weight. It is notably deposited by gravure, flexography, screen printing, surfacing or coating. Particles detectable by touching Preferably, said particles are solid. Alternatively, they are hollow. Said particles may have a spherical, pyramidal, ovoid, polyhedral or similar shape. Preferably, the size of the particles is between 5 and 150 μm. A size greater than or equal to 50 .im is preferable to have a more easily detectable tactile effect.

Preferably, the size D50 of the particles is less than or equal to 90 μm, since above 90 μm, the transfer and coating of the pigment within the binder becomes complex. Preferably, the size of the particles is between 50 and 90 μm. Preferably, said particles are made of plastic, more preferably polyester, polyethylene, polyamide, polypropylene, polyurethane or a mixture thereof. Alternatively, said particles are metal, silica, glass or wax. In general, those skilled in the art will choose a material having sufficient hardness and / or elasticity so that the particles are perceptible after the treatments that will be subjected to the sheet comprising the securing means according to the invention, including printing in size during which a high pressure, generally greater than 2x107 Pa (200 bar), is applied to the sheet. Particles resistant to intaglio printing are polyurethane particles of between 35 and 55 microns in diameter marketed by Daikin Chemical Europe under the name "Daiplacoat ® RHC 230".

Advantageously, the detectably detectable particles are authenticatable and have additional security; they have, for example, diridescence, magnetism or luminescence properties, and more generally any first, second or third level security, as defined above. As a variant, additional secured particles having first, second or third level security characteristics, in particular diridescence, magnetism, or luminescence properties, are present in a mixture with the detectably detectable particles. These particles are for example iridescent particles of "mica-titanium" type. Their size and / or concentration may make them undetectable to 1 naked where appropriate.

Preferably, the detectably detectable particles are based on an elastomeric material, for example based on polyurethane such as Decosphaera particles 90F from Supercolori. These particles have a diameter D50 of between 55 and 75 μm. The choice of an elastomeric material is preferable for absorbing pressure stresses during the soft printing of the secured sheet.

In addition, the material used may be chosen depending on the desired tactile effect, such as a soft or rough touch. A "rough" touch, that is to say the user perceives the reliefs in a particularly pronounced manner, can be obtained by using glass beads, such as those of a diameter of 201 Am, marketed by the company Sovitec under the name Microperl 05020-215 or Prizmalite P2453BTA glass beads with an average particle size of 45 μm and a maximum particle size of 90 μm, sold by Prizmalite Industries. A "soft" feel can be obtained by using polyurethane microspheres, such as those sold by Dainishiseika under the name Daiplacoat RHC535 and ranging in size from 13 to 20 μm. A "soft" feel can also be achieved by using expandable thermoplastic microspheres, such as those sold by Expancel under the name Expancel 820 and ranging in size from 10 to 25 μm.

A "granular and soft" feel can be obtained by using polyurethane microbeads with a diameter of between 35 and 55 μm, such as those sold under the name Daiplacoat® RHC 230 by the company Dainishiseika. Security element Preferably, the security element according to the invention, detectably tactile, is a security thread. Such a yarn is conventionally introduced at least partially by mass into the fibrous substrate during manufacture thereof, and relaxes from one edge to the other of the secured document. It is preferably introduced in window (s). Wide wires, with a width greater than or equal to 2 mm, are particularly suitable for tactile detection. The width of the wire is for example between 1 and 30 mm and its thickness between 5 and 50 iam, preferably between 10 and 301.1.m. In a variant, the security element according to the invention, detectably tactile, is a safety foil. Such foil is conventionally applied to the surface of the substrate by hot pressing.

The security element may comprise a security feature, for example a metallization and / or demetallization, a luminescent or magnetic compound, an optically variable device, an RFID device, a microlens array, an iridescent or interferential pigment, a thermochromic compound or photochromic or liquid crystal. The security feature may be present in the support film or on at least one side of the support film; alternatively, it is applied to the touch layer. Preferably the touch layer is transparent so as to maintain the visual effect of the security feature, when the latter is superimposed at least partially on the touch layer.

The security element can be covered on at least one of its faces by a protective film. This film may be a polyester film, in particular of a thickness less than or equal to 1.1m, for example equal to 6 1.1m. According to a variant, said protective film is coated with an adhesive, in particular a heat-sealing varnish, for example at the rate of 5 g / m 2. According to a preferred variant, the binder of the tactile layer acts as an adhesive during the covering by the protective film. Secured sheet The subject of the invention is also a secured sheet comprising a fibrous substrate on which is applied or at least partially incorporating a security element according to the invention, the sheet having at least one window in which at least partially extends security element, with at least one face not completely covered by the fibrous substrate. The fibrous substrate may have the characteristics defined above. The sheet may have at least one window in which at least partially extends the security element, with at least one face not completely covered by the fibrous substrate. The sheet may have several windows in which the security element extends. At least two windows can have different shapes, including polygonal or ovoid contours, these windows being arranged with a regular spacing or not on the sheet. The secured sheet according to the invention may comprise at least two windows and at least one bridge between the windows, the windows having tactile zones in contrast with non-tactile zones constituted by the bridge or bridges. The difference in tactility between the touch zones defined by the windows where the security element according to the invention relaxes and the non-tactile zones defined by the bridge or bridges and the vellum out of the bridges may allow the recognition of an authentication signature. The window or windows may have simple shapes, for example in the form of a triangular, rectangular, square, round and / or oval pattern. The sheet may have a sequence of windows, for example in the form of a code, or else "fantasy" windows as described in the patent application EP 1 501 980. The shape and the frequency of appearance of the windows, therefore of the tactile zones, can be controlled to create an appropriate signature, allowing to tactilentify a secure document comprising the sheet according to the invention.

Preferably, the sheet comprises a sequence of several tactile zones alternating with non-tactile zones, each touch zone being continuous and the tactility being uniform in all the tactile zones. In other words, in this case, the security element can have the same total thickness in each of the windows and the detectable particles can be uniformly distributed over the support film in the direction of its length. As a variant, the different zones defined by the different windows may have different tactility, for example because the particles detectably detectable are not of the same size or not evenly distributed on the support film. In another variant, a touch zone may have a tactility that varies within the window, for example because the detectably detectable particles are absent in places. The tactile zones defined by the windows are preferably of sufficiently large size, they define in particular a minimum area of 5 mm 2, preferably 15 mm 2 to allow their perception tactilely. For example, in the case of a security thread, the largest width of a touch zone is preferably greater than 1/4, better at half the width of the wire. Preferably, the non-tactile areas, i.e. the bridge (s) and the vellum outside the bridges, are sufficiently wide to allow the contrast with the tactile areas to be perceived. For example, the length of a non-tactile zone in a direction parallel to the length of the security thread is between 1/4 and 4, better between 1/3 and 3, better between 1/2 and 2 times the length of the and adjacent touch zones. The fibrous substrate may be covered on at least one of its faces with a protective film, for example a polyester film, in particular with a thickness of 1.1.m. Secure document The invention also relates to a secure document comprising a secured sheet according to the invention. The secure document is for example a security document or value, such as a means of payment, for example a bank note, a check, a bank card or a restaurant ticket, an identity document, such as a identity card, a visa, a passport, including the personal data page of a passport, an "inlay" or a driving license, a lottery ticket, a ticket or a ticket to cultural events or sports. The invention also relates to a method of manufacturing a security element according to the invention, the detectably detectable particles being dispersed in the binder in the fluid state and applied to the plastic support film before cutting of the latter, especially son. The detectable particles that are tactilely dispersed in the binder in the fluid state are applied to the film by coating or printing. It is notably deposited by gravure, flexography, screen printing, surfacing or coating. The binder is preferably of PVA type or elastomer of PU or acrylic type, as indicated above. The invention also relates to a method of manufacturing a secured sheet according to the invention, comprising a step of inserting the security element into the fibrous substrate having at least one window, to form the secured sheet. The window is for example formed in a wet manner, in particular using a round shape or a flat table. According to one variant, the security element and in particular the tactile layer is modified locally, for example by means of a laser, an embossing or a chemical attack, so as to locally alter its tactility. These modifications can lead to the formation of geometric or alphanumeric patterns, perceptible visually and / or tactilely. Authentication method The invention also relates to a method for authenticating a secure document according to the invention, comprising a step of detecting the touch of the relief of the security element within at least one window of the document. The detection at the touch of the relief is for example a difference in roughness or thickness felt between the tactile and non-tactile areas of the secured sheet. The invention will be better understood on reading the following detailed description, non-limiting implementation examples thereof, and on examining the appended drawing, in which: FIG. 1 represents schematically and in part in section along the length, an example of security thread according to the invention, - Figures 2a and 2b show a front view of two variants of a security thread according to the invention - Figure 3 is a view similar to the figure 1 of a variant of security thread, - Figure 4 shows in bottom view along IV the thread of Figure 3, - Figure 5 shows a view similar to Figure 4 of a variant of security thread according to the invention, - FIG. 6 is a view similar to FIG. 1 of a variant of security thread; FIGS. 7a and 7b show two examples of secure sheets according to the invention in a top view; FIGS. 8a and 8b show diagrammatically and partial, in c according to VIII-V111 of FIG. 7a, two examples of secured sheets according to the invention, and - FIGS. 9a and 9b are partial views in SEM (scanning electron microscopy), respectively from the front and in section, cFun element of FIG. security according to the invention. In the figures, the relative real proportions of the different constituent elements have not always been respected for the sake of clarity.

FIG. 1 shows a security element 1 according to the invention, which comprises a plastic support film 3 on which is disposed a cFun binder layer 2 covering the film 3 and incorporating detectably detectable particles 4. The support film 3, the binder 2 and the particles 4 may be as defined above. The security element may be in the form of a security thread.

The security thread may be intended to be introduced in window (s) 6. The windows 6 define touch zones and alternate with bridges 7 defining non-tactile areas, as detailed below. The tactile particles 4 can be distributed uniformly and without discontinuity on an entire face of the support film, as shown in FIG. 2a.

As a variant, the tactile particles 4 are present in the form of spaced zones, in particular of spaced lines, so as to limit the creation of extra thicknesses at the level of the bridges 7 of the wire, as illustrated in FIG. 2b. The detectably detectable particles may be more or less embedded in the binder layer. A thin layer of binder can cover the particles.

A protective film may cover the touch layer to improve the retention of the particles on the support film. The gap g between two particles is for example greater than or equal to D / 2, where D is the size of the particles, for example their diameter when they are spherical. In a variant not shown, the particles 4 do not uniformly cover the support film 3. In the example shown in FIG. 3, the plastic support film 3 comprises, on a face 5 opposite to that covered by the binder 2, a layer 8 opaque or semi-transparent. This layer 8, made for example by partial metallization, may comprise openings 9 obtained by demetallization. The openings 9 may form patterns, for example alphanumeric characters as illustrated in Figure 4, in the form of Cleartext®. The support film 3 may also carry, in particular on this face 5, other security elements, for example a magnetic strip 10 consisting of a sequence of magnetic "bits" 10 'as illustrated in FIG. 5 or an interference structure 14, as illustrated. In FIG. 6, as illustrated in FIG. 6, the security element 1 can incorporate in the binder 2, other security elements 24, the detectably detectable particles 4, for example a charge of a luminescent or magnetic compound.

The support film 3 may itself also comprise additional security elements 34, of first, second or third level. Preferably, the security element according to the invention is a security thread which is introduced in window (s) in a fibrous substrate 11, for example paper. By way of example, FIGS. 7a and 7b show two secured sheets each having windows 6 in which the security thread 1 according to the invention extends. The windows 6 extend for example on a face 16 and define touch zones that alternate with bridges 7 defining non-tactile areas. The windows 6 may have different shapes. The sheet 15 has for example a succession of triangular and rectangular shaped windows as shown in Figure 7a or a succession of rectangular and square shaped windows of different sizes, as shown in Figure 7b. In a variant not shown, the windows all have the same shape. The tactile effect related to the presence of the security element 1 can be detectable only in the tactile zones defined by the windows 6, and not at the level of the bridges 7.

In the examples illustrated, the security element 1 extends from one edge 17 to the other 18 of the sheet 15. The length d1,2 and d2,3 of a non-tactile zone following longitudinal fax X of the wire 1, is included between 1/4 and 4, better between 1/3 and 3, better between 1/2 and 2 times the length //, / 2, / 3 adjacent touch zones. For example, 0.25 // <d, 2 <4 // and 0.2512 <d1.2 <412. The largest width b of a touch zone is preferably greater than half the width a of the thread. 1. The windows 6 are preferably aligned along a line parallel to the longitudinal fax X of the wire 1, but other arrangements are possible.

Preferably, two adjacent windows 6, in particular having different shapes, are not in contact, so as not to compromise the strength of the sheet and allow a better perception of the tactile areas. The windows 6 may have tactile zones offering the same feeling to the touch, for example because of the use of the same particles 4. In a variant, the tactile zones defined for example by windows of a first shape, in particular triangular, have a tactility different from that of the zones defined by windows of a second form, in particular rectangular. This difference in tactility can for example come from the presence of different tactile particles 4.

The substrate 11 may be monoj and, as illustrated in FIG. 8a. In a variant, the substrate 11 is multij and in particular bij and, as illustrated in FIG. 8b. In the latter case, the security element 1 is for example introduced between the two jets 12, 13 before assembly wet phase thereof. There is shown on the photocopies corresponding to FIGS. 9a and 9b a security element consisting of a support film 3 made of PET, 12 μm thick, and a tactile layer deposited in amounts of 10.2 g / m 2 on the surface of the support 3. Example 1: A polyester film having a thickness of 19 μm is printed full width on one of its faces with a composition of the following formulation: Function Chemical family Quantity (in dry weight) Binder Polyurethane 60% Particle "touch »Balls of 20% polyurethane Crosslinker Carbodiimide 2% Plasticizer Glycerine 15% Additives (wetting, antifoam, pH corrector, viscosity corrector) 3% The dry extract of the composition is adjusted to a value of 50% by addition of water . The viscosity of the composition is adjusted by those skilled in the art according to the deposition method chosen. The composition is printed on the support at a rate of 10 g / m2.

The film thus obtained is cut into strips of width 6 mm and then introduced into windows during the manufacture of a paper substrate. Said windows are arranged to create a code authenticatable to the touch, as shown in Figure 7b. EXAMPLE 2 A polyester film having a thickness of 12 μm is printed full width in gravure on one of its faces with a composition of the following formulation: Function Chemical family Quantity (in dry weight) Binders Polyurethane 35% Vinyl acetate 15% Particle "touch" Glass beads 15% Pigment with interferential effect Mica-Titanium 30% Crosslinking Carbodiimide 2% Additives (wetting, anti-foam.) 3% The dry extract of the composition is adjusted by adding Beau to 50%. The viscosity of the composition is adjusted by those skilled in the art according to the deposition method chosen. The composition is printed on the support at a rate of 12 g / m2. The film thus obtained is covered by lamination of a PET film thickness 6 i.tm coated with a heat-sealing varnish, cut into strips of width 8mm, and then introduced into windows during the manufacture of a paper substrate. Said windows are arranged to create a code authenticatable to the touch, as shown in Figure 7a. The invention is not limited to the illustrated examples. For example, windows 6 may be through. The windows 6 relaxing on the opposite faces of the secured sheet 15 may define tactile zones of different shape and / or arrangement on each of the faces.

The particular features of the various examples can be combined with each other in the sense of non-illustrated variants. The expression "comprising one" is synonymous with "comprising at least one", unless the opposite is specified.

Claims (18)

REVENDICATIONS1. Security element (1) intended to be applied to or incorporated at least partially in a fibrous substrate (11), comprising - a support film (3) made of plastic material - at least one cFun binder layer (2) covering at least partially the support film (3), - detectably detectable particles (4), at least partially incorporated in the binder layer. 2. Element according to claim 1, the binder (2) comprising a heat-sealing adhesive. 3. Element according to claim 1 or 2, the detectably detectable particles (4) having a size greater than or equal to 50 μm. 4. Security element according to any one of claims 1 to 3, the detectably detectable particles (4) and the binder (2) being present on an entire face of the support film (3), without discontinuity. 5. Security element according to any one of claims 1 to 3, the detectably detectable particles (4) being present in the form of spaced apart areas, including spaced lines. 6. Security element according to any one of the preceding claims, the size D50 of the detectably detectable particles (4) being less than or equal to 90 .mu.m. 7. Security element according to any one of the preceding claims, the detectably detectable particles (4) being based on an elastomeric material. 8. Security element according to any one of the preceding claims, being in the form of security thread, in particular of width (a) greater than or equal to 2 mm. 9. Element according to any one of the preceding claims, the detectably detectable particles (4) being authenticatable and having additional securing, including cFiridescence properties, magnetism, or luminescence. 10. Element according to any one of the preceding claims, comprising additional secured particles present in admixture with the detectably detectable particles (4), these additional secure particles having in particular properties cFiridescence, magnetism, or luminescence. 11. Element according to any one of the preceding claims, the binder (2) being deposited in amounts of between 3 and 15 g / m 2 per side, by dry weight. A secured sheet (15) comprising a fibrous substrate (11) to which at least a security element (1) according to any of the preceding claims is applied or at least partially incorporated, the sheet (15) having at least one window ( 6) in which at least partially extends the security element (1), with at least one face not completely covered by the fibrous substrate (11). 13. Secure sheet (15) according to claim 12, comprising several windows in which the security element extends, at least two windows (6) having different shapes, including polygonal or ovoid contours, these windows (6). being arranged with a regular spacing or not on the sheet (15). 14. Secure document comprising a secured sheet (15) as defined in claim 12 or 13. 15. secure document according to claim 14, constituting a means of payment, including a bank note, a check, a credit card or a restaurant ticket, or an identity document, including an identity card, a visa, a personal data page of a passport, an inlay or a driving license, a lottery ticket, a ticket or entry ticket for cultural or sporting events. 16. A method of manufacturing a security element (1) according to any one of claims 1 to 11, the detectably detectable particles (4) being dispersed in the binder (2) in the fluid state and applied to the film support (3) of plastic before cutting the latter, especially son. 17. A method of manufacturing a secured sheet according to claim 12 or 13, comprising a step cInsertion of the security element in the fibrous substrate having at least one window, to form the secured sheet. 18. cFun cFun secure authentication method according to claim 14 or 15, comprising a step of detecting the touch of the relief of the security element within at least one window of the document.