AU2012293634A1

AU2012293634A1 - Moving luminescent security device for a document, and corresponding detection method and detection device

Info

Publication number: AU2012293634A1
Application number: AU2012293634A
Authority: AU
Inventors: Ferederic Beauchet
Original assignee: Banque de France
Current assignee: Banque de France
Priority date: 2011-08-08
Filing date: 2012-08-07
Publication date: 2014-02-27
Anticipated expiration: 2032-08-07
Also published as: EP2741923B1; AU2012293634B2; MX357822B; WO2013020983A1; FR2978937B1; MX2014001476A; FR2978937A1; EP2741923A1

Abstract

The invention relates to a security device, comprising basic luminescent patterns (2, 3) formed on a document so as to react to different excitations, the basic patterns being arranged relative to one another such that a moving overall pattern is formed when the security device is alternately and/or simultaneously subjected to the different excitations.

Description

1 MOVING LUMINESCENT SECURITY DEVICE FOR A DOCUMENT, AND CORRESPONDING DETECTION METHOD AND DETECTION DEVICE 5 The present invention relates to a security device for a document, a method of detection of this security device, and a detection device for the implementation of the method. BACKGROUND OF THE INVENTION 10 It is known that in order to avoid the fraudulent reproduction of objects, especially of documents such as banknotes, or bank cards, it is necessary that the object bear at least one security device which, in order to be effective, must be difficult to reproduce while being 15 easily identifiable. Within the framework of second-level security, a detection tool such as an ultraviolet lamp or an infrared sensor is used. Various security devices using diffusion properties 20 of light are known. In particular, security devices in the form of stamps or ribbons comprising fluorescent signs are known. In practice, to deceive someone of average attention, it suffices that the fraudulently reproduced object comprise any fluorescent sign whatsoever, even if 25 the sign produced is substantially different from the sign used on the authentic security device. From document FR 2 866 460 is also known a method for securing documents by means of a security device emitting a first radiation according to a wide spectrum and 30 a second radiation according to one or more spectral lines in response to excitations. The detection of these two radiations can only be performed by means of a complex device. SUBJECT OF THE INVENTION 2 An aim of the invention is to propose a security device that can be easily stored in memory and analyzed during second-level control. BRIEF DESCRIPTION OF THE INVENTION 5 With a view to achieving this aim, there is proposed a security device comprising at least two luminescent elementary patterns produced on a document so as to react to mutually differing excitations, the elementary patterns being arranged with respect to one 10 another so as to produce an animated global pattern when the security device is subjected in an alternating and/or simultaneous manner to the different excitations. According to the invention, the elementary patterns are produced on one and the same face of the document. 15 Luminescent colors being easily identifiable and the relative position of the elementary patterns being likewise easy to store in memory, the production of two elementary patterns according to a precise arrangement involves employing high-performance hardware which is 20 generally not at the disposal of fraudsters or whose setup can easily be controlled. According to another advantageous aspect of the invention the elementary patterns are positioned precisely with respect to one another. Preferably, the elementary 25 patterns are positioned according to relative positions allowing them to be discerned with the naked eye. Preferably the elementary patterns are adjoining according to direct vision or vision through the window. The slightest offset between the elementary patterns is then 30 visible either because of an overlap of the elementary patterns which is manifested by a different colored line because of the addition of the luminescent colors, or because of a spacing between the elementary patterns which is manifested by a black line under ultraviolet radiation. 35 According to yet another aspect of the invention 3 the latter relates to a method of detection of a security device comprising at least two elementary patterns produced on a document so as to react to mutually differing excitations and arranged with respect to one another so as 5 to produce a global pattern, this method comprising the step of activating the elementary patterns in an alternating and/or simultaneous manner and the step of producing the elementary patterns on one and the same face of the document. The invention also relates to a device for 10 the implementation of this method. BRIEF DESCRIPTION OF THE DRAWINGS Other characteristics and advantages of the invention will become apparent on reading the description which follows of various embodiments of the security device 15 according to the invention with reference to the appended figures, among which: - Figure 1 is a perspective view of a first embodiment of the security device according to the invention, produced on a transparent window of a banknote, 20 - Figure 2 is a sectional view along the line IV-IV of Figure 1, - Figure 3 is a perspective view analogous to that of Figure 1 of a variant of the first embodiment of the invention, 25 - Figure 4 is a partially sectioned perspective view of a second embodiment of the invention, - Figures 5 and 6 are end-on views of the security device of Figure 4 for different excitations, - Figure 7 is a very schematic representation of a 30 device for detecting the security device according to the invention, during the detection of a third embodiment of the security device according to the invention, - Figure 8 is a very schematic representation of a device for detecting the security device according to the 4 invention, during the detection of the first embodiment of the security device according to the invention. DETAILED DESCRIPTION OF THE INVENTION With reference to Figures 1 and 2, the first 5 embodiment of the invention likewise comprises a B-shaped elementary pattern 4 and an F-shaped elementary pattern 5 which this time are both printed on the upper face of the window 1. To facilitate the control of the relative position 10 of the elementary patterns with respect to one another, the positioning of the elementary patterns is carried out so as to allow them to be discerned with the naked eye. For this purpose, the rear edge of the vertical bar of the F coincides here with the inner edge of the vertical bar of 15 the B. As a variant, the vertical bar of the F extends along the axis of the loops of the B. To allow animation of the global pattern thus produced the first elementary pattern 4 is produced by means of an ink excited by a radiation at a first 20 wavelength Al so as to emit a red colored light while the second elementary pattern 5 is excited by a radiation at a second wavelength A2, for example at 365 nanometers, so as to emit a green colored light. The global pattern is furthermore covered with a layer of transparent varnish 22 25 which filters the second wavelength A2. The varnish layer 22 is not represented in Figure 1. In the part common to the two elementary patterns the printing is carried out according to mutually nested points, which have been represented according to 30 intentionally exaggerated dimensions in Figure 1 to facilitate understanding. To produce an animation of the global pattern thus obtained it suffices to alternatively expose each of the faces of the window 1 to a radiation, at the first 35 wavelength Al for the face covered with the varnish 22 and 5 at the second wavelength 22 for the opposite face. By virtue of retinal persistence, the eye of a user perceives the two elementary patterns simultaneously. It is also possible to simultaneously expose the upper face of the 5 window to a radiation at a wavelength Al and the lower face to a radiation at a wavelength 22. In either case when the two elementary patterns are perfectly positioned, the red and green colors appear adjoining inside the loops of the first elementary pattern B. If the colors overlap, a yellow 10 line appears in the overlap zone because of the addition of the colors. If on the contrary 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. 15 By producing the two patterns on one and the same face of the document, the difficulty in suitably registering the two elementary patterns with respect to one another is limited, thereby facilitating the fabrication of the security document while ensuring said security document 20 a high level of security. With reference to Figure 3, a variant of the first embodiment also comprises 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 25 the pinpointing of the two elementary patterns with respect to one another the rear edge of the vertical bar of the F coincides with the inner edge of the vertical bar of the B. To allow animation of the global pattern thus produced, the first elementary pattern 40 is produced by 30 means of an ink excited by a radiation at a first wavelength Al while the second elementary pattern 50 is excited by a radiation at a second wavelength A2. This time, for the two elementary patterns as a whole, the printing is carried out according to points 35 which have been represented according to intentionally 6 exaggerated dimensions in Figure 3 to facilitate understanding. In the part common to the two elementary patterns the printing is therefore carried out by a nesting of the points. 5 By virtue of the printing according to points on the two patterns as a whole, this variant is simpler to fabricate than the first embodiment described previously. Furthermore, it is thus easy to resort to more than two inks to print the two elementary patterns. 10 Figure 4 illustrates a second embodiment in which the security device comprises a first elementary pattern 16 excited by a radiation at a first wavelength Al so as to emit a green colored light. The elementary pattern 16 is partially covered by an elementary pattern 17 comprising a 15 central opening 18. The elementary pattern 17 is excited at a second wavelength A2 so as to emit a red colored light. Furthermore the elementary pattern 17 is filtering in respect of the wavelength A1. When the security device is subjected to a 20 radiation of wavelength A2 on the topside of the window, the security device therefore appears as a red annulus. When the security device is subjected on the topside of the window to a radiation of wavelength Al and a radiation of wavelength A2, the security device appears as a red annulus 25 with a green central patch, as illustrated by Figure 5. When the security device is subjected on the topside of the window to a radiation of wavelength A2 and on the underside of the window to a radiation of wavelength Al, the security device appears in the form of a red disk comprising in its 30 center a green patch surrounded by a yellow zone which corresponds to the zone of overlap of the elementary pattern 16 and of the elementary pattern 17, as illustrated by Figure 6. Figure 7 illustrates in a very schematic manner a 35 device allowing the detection of the security device 7 according to the invention in conjunction with a third embodiment of the invention. In this third embodiment, the security device comprises elementary patterns 19 reacting to an excitation 5 of wavelength Al so as to emit a green light and elementary patterns 20 arranged side by side and reacting to the same excitation so as to emit a red light. In order to be able to differentiate the excitation of the various elementary patterns, the security device furthermore comprises on its 10 face opposite from the elementary patterns a mask 21 comprising openings 23 defining different paths 24 and 25 as a function of the position of the openings 23 with respect to excitation radiation sources 26 and 27 spaced apart and overlooking one and the same face of the 15 document. The openings 23 can have varied shapes and/or can combine various shapes. The detection device comprises a casing 28 in which is fixed a support 29 in the form of a framework arranged overlooking an opening 30 in the casing 28 so as to allow 20 the introduction of a part of the banknote comprising the window. In its upper part the casing 28 comprises a member for viewing the banknote, here a peephole 31 making it possible to observe the part of the banknote comprising the security device. 25 The excitation radiation sources 26 and 27 are linked to a control unit 32 which ensures rhythmic timing of the excitation radiations as a function of the effects sought in conjunction with a particular security device. Figure 8 illustrates in a very schematic manner a 30 device allowing the detection of the security device according to the invention in conjunction with the first embodiment of the invention on a transparent window 1 of a banknote comprising the first B-shaped elementary pattern 4 and the second F-shaped elementary pattern 5. 35 The detection device comprises a casing 128 in 8 which is fixed a support 129 in the form of a framework arranged overlooking an opening 130 in the casing 128 so as to allow the introduction of a part of the banknote comprising the window. 5 The detection device here comprises two excitation radiation sources 126, 127 each arranged overlooking a different face of the banknote and actuatable according to mutually differing modes of excitation. For this purpose, the excitation radiation sources 126 and 127 are linked to 10 a control unit 132 which ensures rhythmic timing of the excitation radiations as a function of the effects sought in conjunction with the banknote. By virtue of the arrangement of the excitation radiation sources 126, 127, it is thus possible to activate 15 the elementary patterns: - in an alternating manner, by firstly actuating one of the excitation radiation sources 126, 127 and then the other of the excitation radiation sources 126, 127; - in a simultaneous manner, by actuating the two 20 excitation radiation sources 126, 127 at the same time. The casing 128 furthermore comprises a member for viewing the banknote, here a camera 130 making it possible to observe the part of the banknote comprising the security device. 25 Of course the invention is not limited to the embodiments described and is amenable to modifications which will be apparent to the person skilled in the art without departing from the scope of the invention, such as defined by the claims. 30 In particular, although the embodiments have all been illustrated in conjunction with a banknote comprising a transparent window, the security device according to the invention can be produced on an opaque support, the luminescent materials and the excitation wavelengths being 35 chosen accordingly so as to take account of the fact that 9 the excitation radiations can be applied only to one face of the document. Within the meaning of the invention two excitations are different from the point at which the two excitations 5 differ by any one of their parameters, that is to say either the excitation wavelength or one of the parameters related to the application of the excitation radiations, for example the composition of the layers through which the excitation radiations pass. 10 Although the invention has been described in conjunction with elementary patterns produced using primary colors, thereby exhibiting the advantage of better luminous efficiency, the invention can also be produced using mixtures of colors making it possible to obtain shades of 15 colors for the production of varied designs. A transparent window within the meaning of the invention is not necessarily totally transparent but may exhibit transparency just sufficient to allow an analysis of an elementary pattern through the window. 20 The direct observation illustrated by Figure 7 can be replaced with observation by means of a sensor such as a camera, as illustrated in Figure 8. In an advantageous manner, a camera can make it possible to view patterns not visible to the naked eye. According to a particular 25 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 global pattern is not perceptible to the naked eye but is perceptible by way of the camera. 30 The detection devices illustrated in Figures 7 and 8 will be able to be adapted for the implementation of the method of detection according to the invention of any embodiment of the security device according to the invention. For this purpose it will suffice to employ at 35 least one excitation radiation source in an appropriate 10 manner to allow the excitation of the elementary patterns. For example, with reference to Figure 7, it is possible to replace the fixed support associated with two excitation members by a pivoting support associated with a single 5 excitation member. Although here the window is produced on the basis of a single film, the window will be able to be produced on the basis of a composite film comprising at least two layers. 10 Although here the elements can be covered with a filtering varnish layer, the elements will be able to be associated with filtering elements other than such a varnish. A filtering element is for example a filtering component incorporated into the substance constituting the 15 window or a filtering varnish applied to one of the faces of the window before the printing of the corresponding elementary pattern, or a sheet made of filtering substance when the window is produced on the basis of a composite film. The filter can also be produced in a local manner, 20 for example by a varying the thickness of the substance. The filter can also be produced on the basis of layers of liquid crystals.

Claims

1. A security device comprising at least two luminescent elementary patterns (4, 5; 16, 17; 19, 20) 5 produced on a document so as to react to mutually differing excitations, the elementary patterns being arranged with respect to one another so as to produce an animated global pattern when the security device is subjected in an alternating and/or simultaneous manner to the different 10 excitations, the security device being characterized in that the elementary patterns are produced on one and the same face of the document.

2. The device as claimed in claim 1, in which the elementary patterns (4, 5; 16, 17) react to excitations of 15 mutually different wavelengths (A1, A2).

3. The device as claimed in claim 2, in which the document comprises a transparent window, the elementary patterns (4, 5) being arranged on one and the same face of the transparent window, at least one of the elementary 20 patterns being covered with a filtering varnish (22) in respect of the wavelength of excitation of the elementary pattern covered with said varnish.

4. The device as claimed in claim 2, in which the document comprises a transparent window, the elementary 25 patterns (4, 5) being arranged on one and the same face of the transparent window, the elementary patterns being covered with a filtering varnish (22) in respect of the wavelength of excitation of one of the elementary patterns.

5. The device as claimed in claim 2, in which one 30 of the elementary patterns (17) partially covers the other of the elementary patterns (16) and is filtering in respect of the wavelength of excitation of the partially covered elementary pattern.

6. The security device as claimed in claim 1, in 35 which the document comprises a transparent window, the 12 elementary patterns (19, 20) being arranged side by side on one and the same face of the transparent window, the transparent window comprising a mask (21) defining different paths for radiations originating from an opposite 5 side of the transparent window from the elementary patterns with respect to the mask.

7. The security device as claimed in claim 1, in which the elementary patterns (4, 5) are positioned according to relative positions allowing pinpointing with 10 the naked eye.

8. The security device as claimed in claim 1, in which the elementary patterns react to excitations of one and the same wavelength.

9. A method of detection of a security device 15 comprising at least two elementary patterns (19, 20; 4, 5) produced on a document so as to react to mutually differing excitations and arranged with respect to one another so as to produce a global pattern, the method comprising the step of activating the elementary patterns in an alternating 20 and/or simultaneous manner, the method being characterized in that it comprises the step of producing the elementary patterns on one and the same face of the document.

10. A detection device for the implementation of the method as claimed in claim 9, comprising at least one 25 excitation radiation source actuatable according to mutually different modes of excitation.

11. The detection device as claimed in claim 10, comprising at least two excitation radiation sources (26, 27) spaced apart overlooking one and the same face of the 30 document.

12. The detection device as claimed in claim 10, comprising at least two excitation radiation sources (126, 127) each arranged facing a different face of the document.

13. The detection device as claimed in claim 10, 35 comprising at least one member for viewing the document.