AU2012293635A1

AU2012293635A1 - Luminescent security device for a document comprising a transparent window

Info

Publication number: AU2012293635A1
Application number: AU2012293635A
Authority: AU
Inventors: Frederic 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: ES2567583T3; WO2013020984A1; FR2978936B1; FR2978936A1; EP2741922B1; EP2741922A1; MX337301B; MX2014001477A; AU2012293635B2

Abstract

The invention relates to a security device for a document comprising a transparent window, which includes at least two basic luminescent patterns (12, 13, 14, 15) arranged so as to react to excitations applied to the window in a controlled manner via at least one filtering device (10, 11). According to the invention, a first basic pattern is formed on a first surface of the transparent window and a second pattern is formed entirely within the body of the transparent window.

Description

1 LUMINESCENT SECURITY DEVICE FOR A DOCUMENT COMPRISING A TRANSPARENT WINDOW. The present invention relates to a security device for a document. 5 BACKGROUND OF THE INVENTION 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 10 effective, must be difficult to reproduce while being easily identifiable. Within the framework of second-level security, a detection tool such as an ultraviolet lamp or an infrared sensor is used. 15 Various security devices using diffusion properties 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 20 object comprise any fluorescent sign whatsoever, even if the sign produced is substantially different from the sign used on the authentic security device. It is also known, especially from document FR 2 889 365, to produce a document with a transparent window 25 serving to support authentication data. The proposed techniques are however the same as those known for an opaque document. SUBJECT OF THE INVENTION An aim of the invention is to propose a security 30 device that can be easily memorised and analyzed during second-level control by exploiting the transparency of the window of the document.

2 BRIEF DESCRIPTION OF THE INVENTION With a view to achieving this aim there is proposed according to the invention a security device for a document comprising a transparent window which comprises at least 5 two luminescent elementary patterns which are designed to react to excitations applied in a controlled manner to the window by way of at least of a filtering member. According to the invention, a first elementary pattern is produced on a first of the faces of the transparent window and a second 10 pattern is produced entirely in the thickness of the transparent window. By altering the filtering properties of the filtering member, which can be disposed at the surface of the window or inside the window, it is thus possible to 15 multiply the security combinations while producing a simple final pattern that can therefore be easily stored in memory to perform a control check. Producing one of the patterns in the thickness of the window, that is to say inside the window, and the other 20 pattern outside the window, thus increases the difficulty of producing two elementary patterns suitably registered with respect to one another while allowing easy control of the relative position of the elementary patterns. According to another advantageous aspect of the 25 invention the elementary patterns are positioned precisely with respect to one another, preferably the elementary patterns are adjoining according to direct vision or vision through the window. The slightest offset between the elementary patterns is then visible either because of an 30 overlap of the elementary patterns which is manifested by a different color 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 BRIEF DESCRIPTION OF THE DRAWINGS 3 Other characteristics and advantages of the invention will become apparent on reading the description which follows of various embodiments of the security device according to the invention with reference to the appended 5 figures, among which: - Figure 1 is a sectional view of a first embodiment of the invention, - Figure 2 is a very schematic representation of a device for detecting the security device according to the 10 invention, during the detection of a second embodiment of the security device according to the invention, - Figure 3 is a very schematic representation of a device for detecting the security device according to the invention, during the detection of the first embodiment of 15 the security device according to the invention. DETAILED DESCRIPTION OF THE INVENTION With reference to Figure 1, in the first embodiment the transparent window is produced on the basis of a composite film here comprising two substantially 20 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. The layer 10 is filtering in respect 25 of this wavelength i.e. of a reduced part of the electromagnetic spectrum, centered on this wavelength. For example, the layer 10 comprises a sheet made of filtering material in respect of the wavelength A1. At the interface between the layer 10 and the layer 30 11 the security device comprises an elementary pattern 13 excited by a radiation at a wavelength A2 so as to emit a red colored light, and here an elementary pattern 14 excited by a radiation at the same wavelength so as to emit a green colored light. The layer 11 is filtering in respect 35 of the wavelength A2. For example, the layer 11 comprises a 4 sheet made of filtering material in respect of the wavelength A2. In an advantageous manner, the two elementary patterns 13 and 14 are disposed internally within the 5 thickness of the transparent window, that is to say inside the transparent window without contact with the faces of the transparent window. The two patterns are therefore protected by said transparent window from outside attack. The security device furthermore here comprises an 10 elementary pattern 15 printed on the lower face of the layer 11 and excited by a radiation at a wavelength A3. In an advantageous manner, producing two patterns in the thickness of the window, a pattern on the upper face of the window and a pattern on the lower face of the 15 window, thus increases the difficulty of producing the elementary patterns suitably registered with respect to one another while allowing easy control of the relative position of the elementary patterns. According to one aspect of the invention, the 20 various elementary patterns are complementary parts of a global pattern. A highly variable global pattern is thus obtained as a function of the excitation radiations applied. Figure 2 illustrates in a very schematic manner a 25 device allowing the detection of the security device according to the invention in conjunction with a second embodiment of the invention. In this second embodiment, the security device comprises elementary patterns 19 which are produced on one 30 of the faces of the window and which react to an excitation of wavelength Al so as to emit a green light and elementary patterns 20 which are produced in the thickness of the window. The elementary patterns 20 are therefore without contact with the faces of the transparent window and inside 35 the transparent window. The elementary patterns 20 react to 5 the same excitation of wavelength Al 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 face opposite from the 5 elementary patterns 19 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 from one another and facing one and the same face of the document. The 10 openings 23 can have varied shapes and/or can combine various shapes. The mask 21 is for example opaque or else the mask 21 is transparent and filtering for at least one wavelength. The mask 21 is thus for example a transparent varnish which filters ultraviolet but allows visible light 15 through. 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 the introduction of a part of the banknote 20 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. The excitation radiation sources 26 and 27 are 25 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 3 illustrates in a very schematic manner a device allowing the detection of the security device 30 according to the invention in conjunction with the first embodiment of the invention. Found here therefore are the security device produced on a transparent window 1 of a banknote comprising the first elementary pattern 12 produced on a first face of 35 the window, the second elementary pattern 13 and the third 6 elementary pattern 14 disposed inside the window and the fourth elementary pattern 15 produced on the opposite face from that of the first elementary pattern 12. The detection device comprises a casing 128 in 5 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. The detection device here comprises three 10 excitation radiation sources 126, 127, 133 each arranged overlooking different faces of the banknote and actuatable according to mutually differing modes of excitation. For this purpose, the excitation radiation sources 126, 127, 133 are linked to a control unit 132 which ensures rhythmic 15 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, 133 it is thus possible to activate the elementary patterns: 20 - in an alternating manner, by firstly actuating one of the excitation radiation sources 126, 127, 133 and then the other of the excitation radiation sources 126, 127, 133; - in a simultaneous manner, by actuating the three 25 excitation radiation sources 126, 127, 133 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 30 device. 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 35 defined by the claims.

7 In particular, within the meaning of the invention two excitations are different from the point at which the two excitations differ by any one of their parameters, that is to say either the excitation wavelength or one of the 5 parameters related to the application of the excitation radiations, for example the composition of the layers through which the excitation radiations pass. Although the invention has been described in conjunction with elementary patterns produced using primary 10 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 colors for the production of varied designs. A transparent window within the meaning of the 15 invention is not necessarily totally transparent but may exhibit transparency just sufficient to allow an analysis of an elementary pattern through the window. The security device will be able to comprise filtering members other than those illustrated. For example 20 the filtering member may be a filtering component incorporated into 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 or covering one of the elementary patterns produced 25 on the faces of the security device etc. The filtering member can also be produced in a local manner, for example by varying the thickness of the material. The filtering member can also be a filter produced on the basis of layers of liquid crystals. 30 The direct observation illustrated by Figure 2 can be replaced with observation by means of a sensor such as a camera, as illustrated in Figure 3. In an advantageous manner, a camera can make it possible to view patterns not visible to the naked eye. According to a particular 35 embodiment, the elementary patterns are printed with an 8 ultraviolet ink and the camera is an ultraviolet camera. As a variant, the elementary patterns are printed with an ink absorbent in the infrared and the camera is an infrared camera. Thus, when the elementary patterns are excited, the 5 global pattern is not perceptible to the naked eye but is perceptible by way of the camera. The detection devices illustrated in Figures 2 and 3 will be able to be adapted for the implementation of the method of detection according to the invention of any 10 embodiment of the security device according to the invention. For this purpose it will suffice to employ at least one excitation radiation source in an appropriate manner so as to allow the excitation of the elementary patterns. For example, with reference to Figure 2, it is 15 possible to replace the fixed support associated with two excitation members by a pivoting support associated with a single excitation member. Although here the window is produced on the basis of a composite film comprising at least two layers, the 20 window will be able to be produced on the basis of a single film or of a composite film comprising a greater number of layers. At least one of the elementary patterns will be produced entirely in the thickness of the window, that is to say in the thickness of one of the films or d the 25 boundary between two films. The elementary pattern will thus be inside the window. The elementary patterns will be able to react to excitations of one and the same wavelength or to different wavelengths. 30

Claims

1. A security device for a document comprising a transparent window which comprises at least two luminescent 5 elementary patterns (12, 13, 14, 15) which are designed to react to excitations applied in a controlled manner to the window by way of at least a filtering member (10, 11), the device being characterized in that a first elementary pattern is produced on a first of the faces of the 10 transparent window and a second pattern is produced entirely in the thickness of the transparent window.

2. The device as claimed in claim 1, in which the elementary patterns (12, 13, 14, 15) react to excitations of mutually differing wavelengths (A1, A2). 15

3. The device as claimed in claim 1, in which the window comprises at least two substantially transparent layers (10, 11), the second pattern being produced between the two layers.

4. The device as claimed in claim 3, in which at 20 least one layer (10, 11) is filtering in respect of an excitation wavelength so as to form the filtering member.

5. The device as claimed in claim 4, in which the filtering layer (10,11) comprises a sheet of filtering material of the excitation wavelength. 25

6. The device as claimed in claim 4, in which the filtering layer (10, 11) comprises a filtering component incorporated into the material constituting said layer.

7. The device as claimed in claim 3, in which the window comprises two substantially transparent layers (10, 30 11), the window comprising a third elementary pattern which is produced on a second of the faces of the transparent window, the transparent layer interposed between the first pattern and the second pattern being filtering in respect of the wavelength at which the first pattern is excited and 35 the transparent layer interposed between the second pattern 10 and the third pattern being filtering in respect of the wavelength at which the third pattern is excited. 7. The security device as claimed in claim 1, in which the elementary patterns (12, 13, 14, 15) are 5 adjoining according to direct vision or for vision through the window.

8. The device as claimed in claim 1, in which the elementary patterns (12, 13, 14, 15) are complementary parts of a global pattern.