FR2952585A1 - SECURITY DOCUMENT INCORPORATING PATTERNS WITH VARIABLE OPTICAL EFFECT - Google Patents

Abstract

The document (10) comprises a substrate (12) and a security element (20) comprising first (22A) and second (22B) patterns carried by the substrate (12). The substrate (12) further comprises a translucent (14) or even transparent zone, within which the first and second patterns (22A, 22B) extend at least partially. The first and second patterns (22A, 22B) are able to produce, within the transparent zone (14), respectively at least first and second colors during an observation of the document (10) in reflection and to switch these first and second colors during an observation of the document (10) in transmission.

Description

The present invention relates to the technical field of security elements for securities documents, such as fiduciary documents or similar. By "fiduciary document" is meant for the purposes of the invention all documents such as banknotes, checks, bank cards, used to transmit a sum of money. "Assimilated document" means any document issued by an administration of the State to prove the identity of a person, his rights to drive a vehicle, such as in particular the identity card, the passport, driving license, etc. By this expression is meant also any document used to authenticate an object of value such as for example a label affixed to a luxury garment. We also hear any document used to authenticate the payment of a tax such as tax stamps. To date, there is a strong demand for document-values comprising security elements that are easily identifiable to the naked eye while being particularly complex to reproduce. Such security features are also referred to as "first level security". The complexity of making such an element generally resides in a diverse combination of printing techniques that are difficult to reproduce with consumer copying equipment (scanner, laser or color inkjet printers, etc.) and / or standard printing equipment. Generally, security elements produce optical effects consisting of optical animations such as contrast sets, color changes, optical illusions, and so on. Thus, it is already known in the state of the art, in particular from document WO 2006/133512, a security document comprising a substrate and a security element capable of changing color as a function of an angle of observation. This security element is formed in a transparent area of the security document and is able to change color according to an observation angle in reflection. However, it is sometimes difficult for an uninformed observer to control unambiguously that the animation he observes corresponds to that prescribed for an authentic document. Indeed, such animation is often observable in specific configurations that the observer may have difficulty determining and there may ultimately remain a doubt as to the authenticity of the document.

There is therefore a need for new means of identification and / or authentication that can, if necessary, contribute to the aesthetics of the latter and whose conformity is easily and unambiguously verifiable, while being difficult to reproduce. to guarantee a great difficulty of counterfeiting.

For this purpose, the subject of the invention is in particular a security document comprising a substrate and a security element comprising first and second patterns carried by the substrate, in which the substrate further comprises a translucent, or even transparent zone, with inside which the first and second patterns extend at least partially, characterized in that the first and second patterns are capable of producing, within this area, respectively at least first and second colors in a observation of the document in reflection and permutation of these first and second colors during an observation of the document in transmission, so as to compose together a final image producing a variable color inversion optical effect according to a transmissive and reflective observation . With the security document according to the invention, the user has no difficulty in understanding that the inversion optical effect that he observes is that expected.

Indeed, the final image produces a very intuitive optical effect since it is a color inversion in two very different and easily identifiable optical observation configurations.

Thus, since the color variation occurs during the passage from a reflection observation to a transmission observation, the user quickly determines the variable optical effect to be observed. In addition, the user is not likely to misposition the document.

Indeed, the user is usually spontaneously led to look through transmission and reflection security document, especially because it is strongly encouraged by the presence of the translucent or transparent area. Colors include all possible colors including white, black, and gray.

In a preferred embodiment, the element comprises a third non-optically variable pattern extending at least partially within the window. This makes it possible to highlight the optical variation of the two patterns with respect to the third optically invariable pattern. Preferably, the first and second patterns extend within the third pattern to further emphasize the enhancement of the optical variation of the first and second patterns. A document according to the invention may further comprise one or more of the features according to which: the first and second patterns are carried respectively by first and second faces of the substrate in register with each other in order to complement each other in order to form the final image; the substrate comprises another substantially opaque zone and in which at least partially extends one of the patterns; the first and second patterns are printed with an ink, such as an iridescent ink with optical interference effect; the ink comprises security tracers, for example fluorescent particles, luminescent particles, reaction type particles at a predefined wavelength and / or thermochromic particles; the document comprises a third pattern made by intaglio printing to form a latent image;

the element comprises a third pattern, extending at least partially in the transparent zone, able to change color according to an observation angle in reflection and to disappear substantially during a transmission observation in the transparent zone ; the third pattern is achieved by printing with an optically variable ink; the patterns are adjacent, even contiguous; the substrate is made of a material essentially comprising paper based on natural and / or synthetic fibers, porous paper and / or paperboard. the document is selected from a bank note and a passport. Other characteristics and advantages of the invention will become apparent in the light of the description which follows, made with reference to the appended drawings in which: FIGS. 1 and 2 show views of the same face of the security document according to a first embodiment embodiments of the invention respectively in reflexive observation and in transmissive observation; Figure 3 shows a sectional view of the document of Figure 1 along the line 3-3; FIGS. 4 and 5 represent views of the same face of the security document according to a second embodiment of the invention respectively in reflexive observation and in transmissive observation; FIGS. 6 and 7 respectively represent views of a first face and a second face of the security document according to a third embodiment of the invention in transmissive and reflexive observation respectively; Figure 8 shows a sectional view of the document of Figure 6 along the line 8-8; Figures 9 to 11 show views of the same face of a document according to a fourth embodiment of the invention respectively at different angles of inclination of the document and in reflective observation.

FIGS. 1 to 3 show a security document according to a first embodiment of the invention. The security document is designated by the general reference 10. In this first embodiment, the document 10 is a banknote. Alternatively, the document 10 may be a passport, a driver's license or any other document that may require security. This document 10 comprises a substrate 12 made for example of a material comprising essentially plastic, paper or a mixture of both but the invention is not limited to a particular material. The substrate material may also have a multilayer structure, where appropriate, with several layers laminated together. The substrate 12 further comprises a translucent zone 14, preferably transparent, designated in the following description by "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 incorporate a security element of the type of transvision (in English "see-through" ) that is to say comprising an image observable transmitted light or even reflected light in the window 14 from one or other of the faces of the document 10. In this first embodiment, the substrate 12 is realized in a transparent plastic material. The plastics material comprises for example essentially a polymer belonging to the family of bi-oriented polypropylenes (BOPP). To obtain the transparent window 14, the substrate 12 is for example covered with a layer of opaque white ink around the location of the window 14 while sparing the latter.

Alternatively, the substrate 12 may be made of a substantially opaque material and may be provided with a hole at the location of the window. A strip of transparent material is then deposited on one of the faces of the substrate to cover the hole and thus form the window. The strip is for example made of a material essentially comprising polyester. Such an exemplary embodiment is illustrated, for example, in FIGS. 9 to 11. In these figures, a strip 18 is shown deposited on the document 10.

The document 10 further comprises a security element 20 carried by the substrate 12. More specifically, the security element 20 comprises first 22A and second 22B patterns extending at least partially in the window 14 and in this first embodiment. embodiment illustrated in Figures 1 to 3, the patterns 22A, 22B extend entirely inside the window 14.

These first and second patterns 22A, 22B are able to produce, within the transparent zone 14, respectively at least first and second colors during an observation of the document in reflection and to swap these first and second colors during an observation of the document in transmission (Figures 1 and 2).

The two patterns 22A and 22B together compose a final image producing a variable color inversion optical effect according to a transmissive and reflective observation. In this first embodiment and as illustrated by FIG. 3, the two patterns 22A and 22B are carried by the same face F1 of the substrate 12. However, because of the transparency properties of the zone 14, the image is observable in transmission and in reflection from one or other of the faces F1 and F2 of the substrate 12. Preferably, the first 22A and second 22B patterns are printed with an iridescent ink with optical interference effect.

It has thus been discovered that an iridescent ink of particular formulation printed in a transparent area of a substrate produces hue variations when the viewing conditions in transmission and reflection vary. This ink, also known as pearl effect ink, incorporates, for example, pigments with small semi-transparent plates that reflect light. These small plates give depth and shine in ink. The size of the pigments makes it possible to vary the satin or scintillating effect of the ink. Thus, a satin effect is obtained with fine pigments and a flicker effect with coarse pigments. Preferably, the pigments are based on mica and are prepared by grinding mica chips on which is deposited a metal layer such as for example titanium oxide or iron oxide. In this case, the color and the optical effect obtained depend in particular on the thickness of this layer. The pigments are also at the origin of color interference obtained by reflection of the incident light either by the semi-transparent pigments or by a film deposited on these pigments. However, the invention is not limited to an iridescent ink obtained from this technique. Alternatively, other inks capable of producing a color change depending on a reflective or transmissive observation may be suitable. In this first embodiment, the first pattern 22A is printed with a first iridescent ink and the second pattern 22B is printed with a second iridescent ink. For example, the first ink is the ink referenced 750008P marketed by the company SICPA which produces a turquoise color in reflection and red in transmission and the second ink is the ink referenced 73UO22P also marketed by the SICPA company which produces a red color in reflection and turquoise in transmission. In addition, in order to enhance the protection of the document against attempts at fraudulent copying or copying, the ink incorporates, for example, security tracers, such as, for example, fluorescent particles, luminescent particles, reaction-type particles. at a predefined wavelength and / or thermochromic particles. Preferably, the first and second patterns are adjacent or even contiguous as shown in the figures. This makes it possible to accentuate the variable optical effect.

In a second embodiment illustrated by FIGS. 4 and 5, the security element 20 further comprises a third optically invariable pattern 22C. When changing the observation conditions, this third pattern does not vary. For example, this third pattern 22C is printed with a traditional colored ink but having no remarkable optical effect, such as for example an ink for offset printing, letterpress, gravure, flexography, screen printing, intaglio, etc.

In a third embodiment illustrated by FIGS. 6 to 8, the first and second patterns 22A, 22B are carried respectively by first F1 and second F2 faces of the substrate 12 in register with each other in order to complement each other. to form the final image. This makes it possible to enhance the security of the document-value 10 by making particularly complex any attempt at fraudulent reproduction of the document. Indeed, the reproduction of the document requires a high precision of identification between the two faces F1 and F2 of the substrate 12. Thus, in the transparent zone 14, the slightest identification inaccuracy is particularly visible and detectable by any informed observer.

Furthermore, as illustrated in FIG. 6, it can be seen that the first pattern 22A extends partially outside the transparent window 14, inside the opaque zone 16. Thus, the first pattern 22A comprises a first region R1, representing the number '100' in the window 14 and a second region R2, representing the symbol '{' in the opaque zone 16.

During a transmission observation of the F1 face (FIG. 6), the region R2 of the first pattern 22A extending in the opaque zone 16 appears in the same color as the region R1 of the same pattern 22A extending into the transparent window 14 but less contrast (the contrast difference between the two regions RI, R2 is shown schematically in Figure 6 by a dashed line outline for a low contrast and a continuous line contour for a strong contrast). In reflexive observation of the second face F2 (Figure 7), the region R2 of the first pattern 22A extending in the opaque zone 16 is not observable. In a fourth embodiment illustrated in FIGS. 9 to 11, the security element comprises a third pattern 22C producing an optically variable effect as a function of the inclination of the document. In addition, the third pattern 22C becomes invisible in transmission (FIG. 11). For example,

the third pattern 22C is printed with an optically variable ink such as the ink referenced 750009V OVI Green / Blue or the ink referenced 73UO21V Sicpastar pink / green marketed by SICPA. In a fifth embodiment not shown in the figures, the security element further comprises a third pattern printed in relief to form a latent image. For example, the third pattern is obtained by deformation of the substrate by means of a press generating a dry stamp. Optionally, alternatively, at least one of the patterns, the first or second pattern, can be achieved by intaglio printing inked to form a tactile mark and provide an additional degree of security to the document. The main aspects of the invention according to the first embodiment will now be described. First, the observer places the substrate 12 with respect to a light source S to observe the substrate 12 in reflection. It observes two distinct colors each produced by the first and second patterns 22A, 22B, for example turquoise for the first pattern 22A and red for the second pattern 22B. Then, the observer then directs the substrate 12 with respect to the light source to observe in transmission the substrate 12. In the transparent zone 14, the image takes on a different appearance by changing the color very clearly. Thus, more particularly, the colors of the patterns 22A, 22B permute. The first pattern 22A turns red while the second pattern 22B becomes turquoise. This change is clearly identifiable to the observer. This optical effect varies in a very intuitive way which removes any ambiguity concerning the authenticity of the document. In addition, it is possible to obtain particularly aesthetic images and easily identifiable optical animations without requiring prior knowledge of the optical effect prescribed. Having two distinct and clearly identifiable orientations for observing a color change also makes it possible to avoid any mispositioning of the document with respect to a light source.

It is understood that the embodiments that have just been described are not limiting in nature and that they can receive any desirable modification without departing from the scope of the invention.

Claims (12)

REVENDICATIONS1. A security document (10) comprising a substrate (12) and a security element (20) comprising first (22A) and second (22B) patterns carried by the substrate (12), wherein the substrate (12) further comprises a translucent zone (14), even transparent, inside which the first and second patterns (22A, 22B) extend at least partially, characterized in that the first and second patterns (22A, 22B) are adapted to producing, within the transparent zone (14), respectively at least first and second colors during an observation of the document (10) in reflection and to swap these first and second colors during an observation of the document ( 10) in transmission, so as to compose together a final image producing a variable color inversion optical effect according to transmissive and reflective observation configurations. 2. Document (10) according to the preceding claim, wherein the first and second patterns (22A, 22B) are carried respectively by first (FI) and second (F2) faces of the substrate (12) locating one of the other in order to complete each other to form the final image. The document (10) according to any one of the preceding claims, wherein the substrate (12) comprises another substantially opaque zone (16) and wherein at least partially extends one of the patterns (22A, 22B). The document (10) according to any one of the preceding claims, wherein the first (22A) and second (22B) patterns are printed with an ink, such as an iridescent ink with optical interference effect. 5. Document (10) according to the preceding claim, wherein the ink comprises security tracers, for example fluorescent particles, luminescent particles, reaction type particles at a predefined wavelength and / or particles. thermochromic. The document (10) according to any one of the preceding claims, comprising a third pattern (22C) made by intaglio printing to form a latent image. The document (10) according to any one of the preceding claims, wherein the element (20) comprises a third pattern (22C) extending at least partially in the transparent zone (14), able to change color. according to an observation angle in reflection and to disappear substantially during a transmission observation in the transparent zone (14). 8. Document (10) according to the preceding claim, wherein the third pattern (22C) is achieved by printing with an optically variable ink. The document (10) according to any one of claims 1 to 5, wherein the element (20) comprises a third non-optically variable pattern (22C) extending at least partially in the transparent region (14). The document (10) according to any one of the preceding claims, wherein the patterns (22A, 22B, 22C) are adjacent, or even contiguous. 11. Document (10) according to any one of the preceding claims, wherein the substrate (12) is made of a material essentially comprising paper based on natural and / or synthetic fibers, porous paper and / or paperboard. . 12. Document according to any one of the preceding claims, being chosen from a bank note and a passport.