FR2978936A1 - LUMINESCENT SECURITY DEVICE FOR A DOCUMENT COMPRISING A TRANSPARENT WINDOW. - Google Patents

Abstract

The invention relates to a security device for a document comprising a transparent window. According to the invention, the window comprises at least two luminescent elementary units (2, 3; 4; 5; 6; 7; 8; 9; 12; 13; 14; 15; 16; 17; 19; 20; 40; ) which are arranged to react to excitations applied in a controlled manner to the window via at least one filtering member.

Description

The present invention relates to a security device for a document. BACKGROUND OF THE INVENTION It is known that in order to avoid the fraudulent reproduction of objects, in particular documents such as banknotes, or bank cards, it is necessary that the object carries at least one security device which, to be effective, must be difficult to reproduce while being easily identifiable.

In the context of second-level security, a detection tool such as an ultraviolet lamp or an infrared sensor is used. Various security devices are known using light scattering properties. In particular, safety devices are known in the form of stamps or tapes with fluorescent signs. In practice, it is sufficient to deceive an average attention interlocutor that the fraudulently reproduced object comprises any fluorescent sign even if the sign produced is substantially different from the sign used on the authentic security device. It is also known, in particular from document FR 2 889 365, to produce a document with a transparent window serving to support authentication data. The proposed techniques are however the same as those known for an opaque document. OBJECT OF THE INVENTION An object of the invention and to propose a security device that can be easily memorized and analyzed during a second level control taking advantage of the transparency of the document window. BRIEF DESCRIPTION OF THE INVENTION With a view to achieving this object, a security device is proposed according to the invention for a document comprising a transparent window, in which the window comprises at least two luminescent elementary patterns which are arranged to react to problems. excitations applied in a controlled manner to the window via at least one filtering member.

By modifying the filtering properties of the filtering element, which can be arranged on the surface of the window or inside the window, it is thus possible to multiply the safety combinations while achieving a simple final pattern and therefore easily memorized to perform a check. According to an advantageous version of the invention the elementary patterns are made on different faces of the transparent window. This increases the difficulty of making two elementary patterns suitably wedged relative to each other while allowing easy control of the relative position of the elementary patterns. According to another advantageous aspect of the invention the elementary patterns are positioned precisely relative to each other, preferably the elementary patterns are joined together in a direct view or through the window. The slightest offset between the elementary patterns is then visible either because of an overlap of the elementary patterns which results in a different color line due to the addition of the luminescent colors, or because of a spacing between the elementary patterns which results in a black line under ultraviolet radiation. BRIEF DESCRIPTION OF THE DRAWINGS Other characteristics and advantages of the invention will appear on reading the following description of various embodiments of the security device according to the invention with reference to the attached figures among which: FIG. 1 is a perspective view of a first embodiment of the security device according to the invention made on a transparent window of a bill, - Figure 2 is a sectional view along the line II-II of the figure 1, - Figure 3 is a perspective view similar to that of Figure 1 of a second embodiment of the invention, - Figure 4 is a sectional view along the line IV-IV of Figure 3, FIG. 5 is a perspective view similar to that of FIG. 1 of a variant of the second embodiment of the invention; FIGS. 6A, 6B, and 6C are front views of a third embodiment of FIG. embodiment of the invention for different excitations FIG. 7 is a sectional view of a fourth embodiment of the invention; FIG. 8 is a perspective view partially in section of a fifth embodiment of the invention; FIGS. 9 and 10 are front views of the security device of FIG. 8 for different excitations; FIG. 11 is a very diagrammatic representation of a device for detecting the security device according to the invention, during detection. of a sixth embodiment of the security device according to the invention, - Figure 12 is a very schematic representation of a device for detecting the security device according to the invention, when detecting the first embodiment of the safety device according to the invention. DETAILED DESCRIPTION OF THE INVENTION With reference to FIG. 1, in the first embodiment, the security device is made on a transparent window 1 of a bank note and comprises a first B-shaped elementary pattern 2. printed on the upper face of the window 1 by means of a luminescent ink substantially transparent to natural light and emitting a red light when the first elementary pattern 2 is subjected to excitation at a wavelength λ 1, for example 254 nanometers . The security device further comprises a second F-shaped elementary pattern 3 printed on the underside of the window 1 by means of a luminescent ink substantially transparent to natural light and emitting a green light when the second elementary pattern 3 is subjected to excitation at the wavelength A1. The two elementary patterns B and F together form an overall pattern BF which is animated by alternately subjecting the upper face and the lower face of 1 to the excitation radiation and / or the two faces of the window to prevent them from being excited simultaneously excitation radiation, the window 1 comprises a filter member which filters the excitation radiation A1. This filtering member is for example a filter component incorporated in the material constituting the window 1, the material then acting itself as a filtering member. In order to facilitate the control of the relative position of the elementary patterns relative to one another, the positioning of the elementary patterns is carried out in order to allow identification with the naked eye, for example the vertical bar of the F extends in the axis of the loops of B.

Referring to Figures 3 and 4 the second mode of the window simultaneously excitation. The elementary radiation of two patterns by a single embodiment of the invention also includes a B-shaped elementary pattern 4 and an F-shaped elementary pattern 5 which are both printed on the upper face of the window 1. To facilitate the identification of the two elementary patterns with respect to each other the rear edge of the vertical bar of the F coincides this time with the inner edge of the vertical bar B. To allow animation of the overall pattern thus produced the first elementary pattern 4 is produced by means of an ink excited by radiation at a first wavelength λ1 to emit a red light while the second elementary pattern 5 is excited by radiation at a second of length λ. A2 wave, for example at 365 nanometers, to emit a green light. The overall pattern is further coated with a clear varnish layer 22 which filters the second wavelength λ2. The lacquer layer 22 is not shown in FIG. 3. In the part common to the two elementary patterns, the printing is carried out according to points which are nested inside each other and which have been represented according to voluntarily exaggerated dimensions in the figure. 3 to facilitate understanding. To realize an animation of the overall pattern thus obtained, it suffices to expose each of the faces of the window 1 alternately to a radiation, to the first wavelength A1 for the face covered with the varnish 22 and to the second wavelength. A2 for the opposite side. Thanks to the retinal persistence, a user's eye perceives the two basic patterns simultaneously. It is also possible to simultaneously expose the upper face of the window to radiation at a wavelength λ1 and the lower face to radiation at a wavelength λ2. In either case, when the two elementary patterns are perfectly positioned, the red and green colors appear contiguous inside the loops of the first elementary pattern B. If the colors overlap, a yellow line appears in the overlapping zone because of the addition of colors. If, on the other hand, the elementary patterns are spaced apart in the zone considered, a black line appears along the back of the elementary pattern F in the zone of the loops of the elementary pattern B. With reference to FIG. 5, a variant of the second embodiment comprises also a B-shaped elementary pattern 40 and an F-shaped elementary pattern 50 which are both printed on the upper face of the window 1. To facilitate the identification of the two elementary patterns with respect to each other the rear edge of the vertical bar of the F coincides with the inner edge of the vertical bar B. To allow animation of the overall pattern thus produced, the first elementary pattern 40 is produced by means of an ink excited by a radiation at a first wavelength Al while the second elementary pattern 50 is excited by radiation at one second of wavelength λ 2. This time, for all of the two basic patterns, the printing is performed according to points which have been represented according to voluntarily exaggerated dimensions in Figure 5 for ease of understanding. In the common part to the two basic patterns, the printing is performed by a nesting of the points.

Thanks to the printing according to points on all of the two patterns, this variant is simpler to manufacture than the second embodiment described above. In addition, it is thus easy to use more than two inks to print the two basic patterns.

FIGS. 6A to 6C illustrate the third embodiment in which the security device comprises two elementary patterns 6, 7 printed on the upper face of the window 1. The elementary pattern 6 is formed of the euro symbol whose ends have been truncated and the elemental pattern 7 to an arrowhead shape. These two elementary patterns are made with the same ink substantially transparent to natural light and emitting a green light when excited by radiation at a wavelength λ 1. On the underside of the window 1 the security device comprises a series of segments 8 forming complementary elements of the elementary pattern 6 to produce a global pattern symbolizing the euro, and a series of geometric figures 9 forming complementary elements of the elementary pattern 7 to make a global star-shaped pattern as shown in Figure 6C. The different elementary patterns can be made either according to the first embodiment, that is to say using inks sensitive to the same wavelength Al on the faces of a window filtering this wavelength, or according to the second embodiment that is to say using materials excited by radiation at different wavelengths. It is also possible to combine elementary patterns excited at the wavelength λ1 on both sides of the window with an elementary pattern excited at the wavelength λ 2 on one of the faces of the window so as to obtain a particular effect depending on the activation sequences of the excitation radiation. FIG. 7 illustrates a fourth embodiment in which the transparent window is this time made from a composite film comprising two substantially transparent layers 10 and 11. The security pattern comprises a first elementary pattern 12 printed on the upper face of the layer 10 with a luminescent ink emitting a blue light when it is excited at a first wavelength A1. Layer 10 is a filter of this wavelength. At the interface between the layer 10 and the layer 11, the security device comprises an elementary pattern 13 excited by radiation at a wavelength λ2 to emit a red light, and an elementary pattern 14 excited by a radiation at the same wavelength to emit a green light. The layer 11 is filtering the wavelength λ 2. The security device further comprises an elementary pattern 15 printed on the lower face of the layer 11 and excited by radiation at a wavelength λ3. A highly variable overall pattern is thus obtained as a function of the excitation radiations applied. FIG. 8 illustrates a fifth embodiment in which the security device comprises a first elementary pattern 16 excited by radiation at a first wavelength λ1 to emit a green light. The elementary pattern 16 is partially covered by an elementary pattern 17 having a central opening 18. The elementary pattern 17 is excited to a second of wavelength λ 2 to emit a red light. In addition, the elementary pattern 17 is filtering the wavelength A1. When the safety device is subjected to radiation of wavelength λ2 on the top of the window, the safety device thus appears as a red ring. When the safety device is subjected on the top of the window to radiation of wavelength λ1 and radiation of wavelength λ2, the safety device appears as a red ring with a green central pellet as illustrated by FIG. figure 9.

When the security device is subjected on the top of the window to a radiation of wavelength λ2 and on the underside of the window to a radiation of wavelength λ1, the security device appears in the form of a disk red having in its center a green dot surrounded by a yellow zone which corresponds to the overlap zone of the elementary pattern 16 and the elementary pattern 17, as illustrated in FIG. 10. FIG. 11 very schematically illustrates a device allowing the detection of the safety device according to the invention in connection with a sixth embodiment of the invention. In this sixth embodiment, the safety device comprises elementary patterns 19 reacting to an excitation of wavelength λ1 to emit a green light and elementary patterns 20 arranged side by side and reacting to the same excitation to emit light. red. In order to be able to differentiate the excitation of the different elementary patterns, the safety device further comprises on its face opposite to the elementary patterns a mask 21 having openings 23 defining different paths 24 and 25 as a function of the position of the openings 23 relative to each other. to excitation radiation sources 26 and 27 spaced apart from each other with respect to one and the same face of the document. The openings 23 may have various shapes and / or combine different shapes. The detection device comprises a housing 28 in which is fixed a support 29 in the form of a frame disposed opposite an opening 30 in the housing 28 to allow the introduction of a portion of the bill containing the window. At its upper part the housing 28 comprises a ticket display member, here an eyelet 31 for observing the portion of the ticket comprising the security device.

The excitation radiation sources 26 and 27 are connected to a control unit 32 which provides a timing of the excitation radiation as a function of the desired effects in relation to a particular security device.

Figure 12 very schematically illustrates a device for detecting the security device according to the invention in connection with the first embodiment of the invention. Here we find the security device made on a transparent window 1 of a bank note comprising the first elementary pattern 2 in the form of B and the second elementary pattern 3 in the form of F. The detection device comprises a housing 128 in which is fixed a support 129 in the form of a frame disposed opposite an opening 130 in the housing 128 to allow the introduction of a portion of the bill containing the window. The detection device here comprises two excitation radiation sources 126, 127 each disposed facing a different face of the note and operable in different modes of excitation from each other. For this purpose, the excitation radiation sources 126 and 127 are connected to a control unit 132 which provides a timing of the excitation radiation as a function of the desired effects in relation to the note. Thanks to the arrangement of the excitation radiation sources 126, 127, it is thus possible to activate the elementary patterns. alternately, by first actuating one of the excitation radiation sources 126, 127 and then the other of the excitation radiation sources 126, 127; - Simultaneously, by actuating the two sources of excitation radiation 126, 127 at the same time. The housing 128 further comprises a ticket display member, here a camera 130 for observing the portion of the ticket comprising the security device. Naturally, the invention is not limited to the embodiments described and is subject to modifications which will be apparent to those skilled in the art without departing from the scope of the invention as defined by the claims. In particular, in the sense of the invention, two excitations are different from the moment when the two excitations differ by any of their parameters, that is to say either the excitation wavelength or the one of the parameters related to the application of the excitation radiations, for example the composition of the layers traversed by the excitation radiations. Although the invention has been described in connection with elementary patterns made using primary colors, which has the advantage of a better light output, the invention can also be achieved using color blends allowing obtain nuances of colors for the realization of various drawings. A transparent window within the meaning of the invention is not necessarily completely transparent but may have a transparency just sufficient to allow analysis of an elementary pattern through the window. Although in the second embodiment the filter varnish layer 22 covers the entire pattern, similar operation could be achieved by covering only the elemental pattern 5 with filter varnish. The security device may include other filtering members than those illustrated. For example, the filtering member may be a filtering component incorporated in the material constituting the window, a filtering varnish applied to one of the faces of the window 1 before the printing of the corresponding elementary pattern, a sheet of filtering material when the window 1 is made from a composite film ... The filter element can also be made locally, for example by a variation in thickness of the material. The filter member may also be a filter made from layers of liquid crystals. The direct observation illustrated in FIG. 11 can be replaced by an observation by means of a sensor such as a camera as illustrated in FIG. 12. Advantageously, a camera can make it possible to visualize patterns that are not visible to the naked eye. . According to a particular embodiment, the elementary patterns are printed with an ultraviolet ink and the camera is an ultraviolet camera. Thus, when the elementary patterns are excited, the overall pattern is not noticeable to the naked eye but is perceptible through the camera.

The detection devices illustrated in FIGS. 11 and 12 may be adapted for carrying out the detection method according to the invention of any embodiment of the safety device according to the invention. It will suffice for this purpose to deposit at least one excitation radiation source adequately to allow excitation of the elementary patterns. For example, with reference to FIG. 11, it is possible to replace the fixed support associated with two excitation members by a pivoting support associated with a single excitation member.

Claims (10)

REVENDICATIONS1. Security device for a document having a transparent window, characterized in that the window comprises at least two luminous elementary patterns (2, 3, 4, 5; 6, 7, 8, 9; 12, 13, 14, 15; , 17; 19, 20; 40, 50) which are arranged to react to excitations applied in a controlled manner to the window via at least one filtering member (10, 11, 17, 22). 2. Safety device according to claim 1 wherein the elementary patterns (1, 2) are made on different faces of the transparent window. 3. Safety device according to claim 2 wherein the elementary patterns (1, 2) react to excitations of the same wavelength (A1) and wherein a filter of this wavelength is arranged between patterns. elementals extending on different faces. 4. Device according to claim 2 wherein the elementary patterns (4, 5; 40, 50) react to excitations of different wavelengths (A1, A2) from each other. 5. Device according to claim 4 wherein the elementary patterns (4, 5) are made on the same face of the window and in that at least one of them is covered with a filter varnish of the length corresponding excitation wave. 6. Safety device according to claim 1 wherein the elementary patterns (4, 5; 40, 50; 6, 7, 8, 9) are contiguous in direct vision or in vision through the window. 7. Device according to claim 1 wherein the elementary patterns (6, 7, 8, 9) are complementary parts of a global pattern. 8. Device according to claim 1 wherein the window comprises several substantially transparent layers (10, 11) of which at least one is filtering an excitation wavelength, and in that at least one elementary pattern (13 , 14) is made between two layers. 9. Device according to claim 1 wherein one of the elementary patterns (17) partially overlaps another elementary pattern (16) and is filtering an excitation wavelength of the partially covered elementary pattern (16). The security device according to claim 1, wherein the unitary patterns (19, 20) are arranged side by side, and in that the transparent window comprises a mask (21) defining the different paths for radiation coming from one side. of the transparent window opposite the elementary patterns relative to the mask.