AU2010317769B2

AU2010317769B2 - Security document including patterns with variable optical effect

Info

Publication number: AU2010317769B2
Application number: AU2010317769A
Authority: AU
Inventors: Xavier Borde; Julien Gillot; Sebastien Hamon
Original assignee: Oberthur Technologies SA
Current assignee: Idemia France SAS
Priority date: 2009-11-16
Filing date: 2010-11-16
Publication date: 2014-09-18
Anticipated expiration: 2030-11-16
Also published as: FR2952585A1; RU2012125057A; PL2501554T3; EP2501554B1; AU2010317769A1; ZA201203057B; CN102725149B; CA2778842A1; CN102725149A; RU2556492C2; BR112012011559A2; EP2501554A1; WO2011058288A1

Abstract

The invention relates to a document (10) which includes a substrate (12) and a security element (20) including first (22A) and second (22B) patterns supported by the substrate (12), the substrate (12) also including a translucent or transparent area (14), with the first and second patterns (22A, 22B) at least partially extending therein. The first and second patterns (22A, 22B) are suitable for producing, inside the transparent area (14), at least first and second colours respectively when observing the document (10) by reflection and for switching said first and second colours when observing the document (10) being sent.

Description

1 SECURITY DOCUMENT INCLUDING PATTERNS WITH VARIABLE OPTICAL EFFECT The present invention relates to the technical field of security elements for documents of value, such as 5 security documents or the like. The term "security document" is used in the meaning of the invention to cover any documents that are used for transmitting sums of money, such as bank notes, checks, bank cards. 10 The term "like document" is used to mean any document issued by a State authority to attest a person's identity, right to drive a vehicle, such as in particular identity cards, passports, driving licenses, etc. This term also covers any document used to authenticate an 15 article of value such as for example a label applied to a luxury garment. The term also covers any document used to authenticate payment of a tax, such as tax stickers. At present there is a strong demand for documents of value that include security elements that are easily 20 identified by the naked eye while also being particularly complex to reproduce. Such security elements are also referred to as "first level" security elements. The complexity of making such an element generally lies in various combinations of printing techniques that 25 are difficult to reproduce with consumer reprographic equipment (scanners, laser printers, color ink jet printers, etc.) and/or with standard printers' equipment. In general, security elements produce optical effects that consist in optical animations such as 30 varying contrast, changing colors, optical illusions, etc. Thus, in the state of the art, and in particular from document WO 2006/133512, a security document is already known that comprises a substrate and a security 35 element suitable for changing color as a function of angle of observation. The security element is formed in a transparent zone on the security document and it is 2 suitable for changing color as a function of angle of observation in reflection. Nevertheless, it is sometimes difficult for an untrained observer to verify unambiguously that the observed animation does indeed correspond to that specified for a document that is authentic. Such an animation is often observable under precise configurations that the operator might have difficulty in determining, and doubt may therefore remain as to the authenticity of the document. There therefore exists a need for novel identification and/or authentication means that are capable, where appropriate, of contributing to the appearance of a document and that can be easily verified unambiguously for compliance, while being difficult to reproduce, so as to guarantee that they are very difficult to counterfeit. OBJECT It is the object of the present invention to address the above-mentioned need. SUMMARY The present invention provides a security document, wherein the document comprises a substrate and a security element having first and second patterns carried by the substrate, wherein the substrate further includes a zone that is transparent or translucent, within which the first and second patterns extend at least in part, the first and second patterns are suitable for producing within the transparent zone respectively at least first and second colors when the document is observed in reflection and for interchanging the first and second colors when the document is observed in transmission, so that together they make up a final image producing an 9006953 1 3 optical effect of color inversion that varies as a function of the observation configuration in transmission or in reflection, and wherein the element includes a third pattern extending at least in part in the transparent zone and suitable for being colored with at least one color during observation in reflection and for substantially disappearing during observation in transmission in the transparent zone. By means of the security document of the invention, the user has no difficulty in understanding that the observed optical inversion effect is the expected effect. The final image produces an optical effect that is very intuitive since it consists in inverting colors in two optical observation configurations that are very different and easily identifiable. Thus, since the change in color occurs on passing from observation in reflection to observation in transmission, the user can quickly determine what variable optical effect should be observed. In addition, there is no danger of the user positioning the document wrongly. A user generally looks at a security document spontaneously both in transmission and in reflection, in particular because the presence of the translucent or transparent zone encourages this very strongly. The colors include all possible colors, including white, black, and gray. In a preferred embodiment, the element includes a third pattern that does not vary optically and that extends at least in part within the window. This makes it possible to emphasize the optical variation of the two patterns 3a compared with the third pattern that is optically invariable. Preferably, the first and second patterns extend inside the third pattern so as to emphasize more clearly the optical variation of the first and second patterns. In a preferred embodiment, the document may also include one or more of the following features: - the first and second patterns are carried respectively by first and second faces of the substrate in register with each other so that together they form the final image; 9006953 1 4 - the substrate includes another zone that is substantially opaque and in which one of the patterns extends at least in part; - the first and second patterns are printed using an 5 ink such as an iridescent ink having an interference optical effect; - the ink includes security tracers, for example fluorescent particles, luminescent particles, particles of the type that react at a predefined wavelength, and/or 10 thermochromic particles; - a third pattern is made by copperplate printing so as to form a latent image; - the element includes a third pattern extending at least in part in the transparent zone and suitable for 15 being colored with at least one color during observation in reflection and for substantially disappearing during observation in transmission in the transparent zone; - the third pattern is made by printing using an optically-variable ink; 20 the patterns are adjacent, or indeed contiguous; - the substrate is made of a material that essentially comprises paper based on natural and/or synthetic fibers, porous paper, and/or card; - the document is selected from a bank note and a 25 passport; and - at least the first and second patterns are carried by a first face and the third pattern is carried by a second face opposite from the first face, the third pattern being arranged at least in part to overlap each 30 of the first and second patterns in such a manner that the first and second patterns are hidden at least in part by the third pattern when observing the second face in reflection, and are revealed by the transparency of the third pattern when observing in transmission from the 35 second face. Other characteristics and advantages of the invention appear in the light of the following 5 description made with reference to the accompanying drawings, in which: - Figures 1 and 2 are views of the same face of a security document in a first embodiment of the invention 5 shown respectively when observed in reflection and in transmission; - Figure 3 is a section view of the Figure 1 document on line 3-3; - Figures 4 and 5 are views of the same face of a 10 security document in a second embodiment of the invention shown respectively when observed in reflection and in transmission; - Figures 6 and 7 are views of first and second faces respectively of a security document in a third 15 embodiment of the invention as observed respectively in transmission and in reflection; - Figure 8 is a section view of the Figure 6 document on line 8-8; - Figures 9 to 11 are views showing the same face of 20 a document in a fourth embodiment of the invention observed in reflection at different angles of inclination of the document; and - Figures 12 to 14 are views of the same face of a document in a sixth embodiment of the invention observed 25 from different points of view in reflection and in transmission. Figures 1 to 3 show a security document in a first embodiment of the invention. The security document is given overall reference 10. 30 In this first embodiment, the document 10 is a bank note. In a variant, the document 10 could be a passport, a driving license, or any other document that might need to be made secure. The document 10 comprises a substrate 12, e.g. made 35 of a material that essentially comprises plastic, paper, or a mixture of plastic and paper, however the invention is not limited to any particular material. Where 6 appropriate, the material of the substrate may also present a multilayer structure comprising a plurality of layers that are laminated together. The substrate 12 also includes a translucent zone 14 S that is preferably transparent and that is referred to in the description below as a "window". This zone 14 is preferably surrounded by an opaque zone 16. The presence of such a window 14 in a security document 10 makes it possible in particular to 10 incorporate a see-through type security element, i.e. comprising an image that is observable in transmitted light or even in reflected light in the window 14 from one or the other of the faces of the document 10. In a first embodiment, the substrate 12 is made in a 15 transparent plastics material. By way of example, the plastics material essentially comprises a polymer belonging to the family of bi-oriented polypropylenes (BOPP). In order to obtain the transparent window 14, the substrate 12 may, for example, be covered in a layer 20 of opaque white ink around the location of the window 14 while avoiding the window itself. In a variant, the substrate 12 may be made of a material that is substantially opaque and it may be provided with a hole at the location of the window. A 25 first strip of transparent material is then placed on one of the faces of the substrate in order to cover the hole and thus form the window. By way of example, the strip may be made of a material that essentially comprises polyester. One such embodiment is shown in Figures 9 to 30 11. These figures also show a strip 18 placed on the document 10. The document 10 also includes a security element 20 carried by the substrate 12. More precisely, the security element 20 has first and second patterns 22A and 35 22B extending at least in part in the window 14, and in this first embodiment shown in Figures 1 to 3 the 7 patterns 22A and 22B extend entirely within the window 14. These first and second patterns 22A and 22B are suitable for producing within the transparent zone 14 5 respectively at least first and second colors when the document is observed in reflection and for interchanging these first and second colors when the document is observed in transmission (Figures 1 and 2). The two patterns 22A and 22B thus together make up a 10 final image producing an optical effect of color inversion that varies as a function of whether observation is in transmission or reflection. In the first embodiment and as can be seen in Figure 3, the two patterns 22A and 22B are carried on the 15 same face F1 of the substrate 12. Nevertheless, because of the transparency properties of the zone 14, the image can be observed in transmission and in reflection from both of the faces F1 and F2 of the substrate 12. The first and second patterns 22A and 22B are 20 preferably printed using an iridescent ink having an interference optical effect. It has thus been discovered that an iridescent ink of a particular formulation printed on a transparent zone of a substrate produces variations in hue when the 25 transmission or reflection conditions of observation vary. This ink, also known as a perlescent effect ink, may incorporate, for example, pigments that are provided with small semi-transparent flakes that reflect light. These 30 small flakes impart depth and gloss to the ink. The size of the pigments makes it possible to vary the smooth or scintillating effect of the ink. Thus, a smooth effect is obtained with fine pigments and a scintillating effect is obtained with coarse pigments. The pigments are 35 preferably based on mica and they are prepared by grinding chips of mica having a metallic layer deposited thereon, such as for example a layer of titanium oxide or 8 iron oxide. Under such circumstances, the color and the optical effect that are obtained depend in particular on the thickness of the layer. The pigments also give rise to color interference that is obtained by reflection of 5 the incident light either by the semi-transparent pigments or by a film deposited on the pigments. In any event, the invention is not limited to an iridescent ink obtained using this technique. In a variant, other inks capable of producing a 10 color change as a function of observation in reflection or transmission may be suitable. In this first embodiment, the first pattern 22A is printed using a first iridescent ink and the second pattern 22B is printed using a second iridescent ink. 15 For example, the first ink is the ink referenced 75U008P sold by the supplier SICPA, which ink produces a turquoise color in reflection and a red color in transmission, and the second ink is the ink referenced 73UO22P likewise sold by the supplier SICPA, which ink 20 produces a red color in reflection and a turquoise color in transmission. In addition, in order to reinforce the protection of the document 10 against fraudulent attempts at reproduction or copying, the ink may for example 25 incorporate security tracers, such as for example: fluorescent particles, luminescent particles, particles of the type that react at a predefined wavelength, and/or thermochromic particles. The first and second patterns are preferably 30 adjacent or even contiguous, as shown in the figures. This serves in particular to accentuate the variable optical effect. In a second embodiment shown in Figures 4 and 5, the security element 20 further includes a third pattern 22C 35 that is optically invariable. On a change in observation conditions, this third pattern does not vary. For example, the third pattern 22C is printed with a 9 conventional colored ink that presents no remarkable optical effect, such as, for example, an ink for offset, letterpress, photogravure, flexographic, silkscreen, copperplate, etc. printing. 5 In a third embodiment shown in Figures 6 to 8, the first and second patterns 22A and 22B are carried respectively by first and second faces F1 and F2 of the substrate 12 in register with each other so that together they form the final image. This serves to reinforce the 10 security of the document of value 10 by making any fraudulent attempt at reproducing the document particularly complex. Reproducing the document requires great accuracy in registration between the two faces F1 and F2 of the substrate 12. Thus, in the transparent 15 zone 14, the slightest inaccuracy of registration is particularly visible and can be detected by any knowledgeable observer. Furthermore, as shown in Figure 6, it can be seen that the first pattern 22A extends in part outside the 20 transparent window 14 into the opaque zone 16. Thus, the first pattern 22A comprises a first region R1 representing the digit "0" in the window 14, and a second region R2 representing the sign "E" in the opaque zone 16. 25 When observing the face F1 in transmission (Figure 6), the region R2 of the first pattern 22A in the opaque zone 16 appears to have the same color as the region R1 of the same pattern 22A that lies in the transparent window 14, but with less contrast (the 30 difference in contrast between the two regions R1 and R2 is represented in Figure 6 by a discontinuous outline for weak contrast and by a continuous outline for strong contrast). When observed in reflection from the second face F2 (Figure 7), the region R2 of the first pattern 35 22A occupying the opaque zone 16 cannot be seen. In a fourth embodiment shown in Figures 9 to 11, the security element includes a third pattern 22C producing 10 an optical effect that varies as a function of the angle of inclination of the document. In addition, the third pattern 22C becomes invisible in transmission (Figure 11). For example, the third pattern 22C may be 5 printed using an optically variable ink such as the ink referenced 75U009V OVI Green/Blue or the link referenced 73UO21V Sicpastar pink/green sold by SICPA. In a fifth embodiment that is not shown in the figures, the security element also includes a third 10 pattern that is printed in relief in order to form a latent image. For example, the third pattern may be obtained by deforming the substrate by means of a press that produces an embossed mark. In a variant, at least one of the first or second patterns may be made by 15 copperplate printing using an ink for forming a mark that can be felt, thereby providing an additional degree of security to the document. In a sixth embodiment shown in Figures 12 to 14, the element 20 includes a third pattern 22C extending at 20 least in part in the transparent zone 14. This third pattern 22C is suitable for appearing when observed in reflection (Figures 12 and 13) and for disappearing substantially when observed in transmission in the transparent zone 14 (Figure 14). 25 The third pattern 22C is preferably suitable for changing color as a function of the angle of observation in reflection and for substantially disappearing when observed in transmission in the transparent zone 14, as shown in Figures 12 and 13 which show the face F2 30 carrying the third pattern 22C as seen in two distinct configurations for observation in reflection. Thus, when the face F2 is viewed in reflection from a first viewpoint, as shown in Figure 12, the third pattern 22C takes a first color, and when the face F2 is viewed in 35 reflection from a second viewpoint, as shown in Figure 13, the third pattern 22C takes a second color.

11 Preferably, at least the first and second patterns 22A and 22B are carried by a first face F1, while the third pattern 22C is carried by the second face F2 that is opposite from the first face Fl. Under such 5 circumstances, the third pattern 22C is arranged at least in part to overlap each of the first and second patterns 22A and 22B such that the first and second patterns 22A and 22B are at least partially hidden by the third pattern 22C when the second face F2 is observed in 10 reflection, and revealed by the transparency of the third pattern 22C when observing in transmission from the second face F2. In the first and second observation configurations, the first and second patterns 22A and 22B are partially 15 hidden by the third pattern 22C. In the third observation configuration in transmission as shown in Figure 14, the two patterns 22A and 22B are revealed by the third pattern 22C being transparent. In a variant, the third pattern 22C may hide the 20 first and second patterns 22A and 22B completely (Figures 12 and 13). The main aspects of the invention in the first embodiment are described below. Firstly, the observer places the substrate 12 25 relative to a source of light S in order to observe the substrate 12 in reflection. Two distinct colors can be seen, each produced by the first and second patterns 22A and 22B, e.g. turquoise for the first pattern 22A and red for the second pattern 22B. 30 Thereafter, the observer orients the substrate 12 relative to the light source so as to observe the substrate 12 in transmission. In the transparent zone 14, the image takes on a different aspect by changing color very distinctly. Thus, more particularly, the 35 colors of the patterns 22A and 22B are interchanged. The first pattern 22A becomes red while the second pattern 12 22B becomes turquoise. This change is clearly identifiable for the observer. This optical effect varies in a manner that is very intuitive, thereby lifting any ambiguity concerning the 5 authenticity of the document. In addition, it is possible to obtain images that are particularly pleasing and optical animations that are easily identifiable without requiring prior knowledge of the particular optical effect. The mere fact of having two clearly 10 distinct and readily identifiable orientations for observing a color change also makes it possible to avoid any poor positioning of the document relative to the light source. It will naturally be understood that the embodiments 15 described above do not present any limiting character and that they may receive any desirable modification without thereby going beyond the ambit of the invention.

Claims

1. A security document, wherein the document comprises a substrate and a security element having first and second patterns carried by the substrate, wherein the substrate further includes a zone that is transparent or translucent, within which the first and second patterns extend at least in part, the first and second patterns are suitable for producing within the transparent zone respectively at least first and second colors when the document is observed in reflection and for interchanging the first and second colors when the document is observed in transmission, so that together they make up a final image producing an optical effect of color inversion that varies as a function of the observation configuration in transmission or in reflection, and wherein the element includes a third pattern extending at least in part in the transparent zone and suitable for being colored with at least one color during observation in reflection and for substantially disappearing during observation in transmission in the transparent zone.

2. A document according to claim 1, wherein the third pattern is suitable for changing color as a function of angle of observation in reflection.

3. A document according to any one of the preceding claims, wherein at least the first and second patterns are carried by a first face and the third pattern is carried by a second face opposite from the first face, the third pattern being arranged at least in part to overlap each of the first and second patterns in such a manner that the first and second patterns are hidden at least in part by the third pattern when observing the second face in reflection, and are revealed by the transparency of the third pattern when observing in transmission from the second face. 14

4. A document according to any one of the preceding claims, wherein the first and second patterns are carried respectively by first and second faces of the substrate in register with each other so that together they form the final image.

5. A document according to any one of the preceding claims, wherein the substrate includes another zone that is substantially opaque and in which one of the patterns extends at least in part.

6. A document according to any one of the preceding claims, wherein the first and second patterns are printed using an ink such as an iridescent ink having an interference optical effect.

7. A document according to the preceding claims, wherein the ink includes security tracers.

8. A document according to claim 7, wherein the security tracers comprise at least one of fluorescent particles, luminescent particles, particles of the type that react at a predefined wavelength, and thermochromic particles.

9. A document according to any one of the preceding claims, wherein the third pattern is made by copperplate printing so as to form a latent image.

10. A document according to any one of the preceding claims, wherein the third pattern is made by printing using an optically-variable ink.

11. A document according to any one of the preceding claims, wherein the patterns are adjacent or contiguous. 9006953 1 15

12. A document according to any one of the preceding claims, wherein the substrate is made of a material that essentially comprises paper based on natural and/or synthetic fibers, porous paper, and/or card.

13. A document according to any one of the preceding claims, the document being selected from a bank note and a passport.

14. A document substantially as hereinbefore described with reference to any one of the embodiments as that embodiment is shown in Figures 4 to 14 of the accompanying drawings. Oberthur Technologies Patent Attorneys for the Applicant/Nominated Person SPRUSON & FERGUSON