AU2016363653A1

AU2016363653A1 - Security document and element

Info

Publication number: AU2016363653A1
Application number: AU2016363653A
Authority: AU
Inventors: Xavier Borde; Guillaume CHAPEAU; Julien Gillot
Original assignee: Oberthur Fiduciaire SAS
Current assignee: Oberthur Fiduciaire SAS
Priority date: 2015-12-01
Filing date: 2016-11-29
Publication date: 2018-06-14
Also published as: KR20180097600A; CN108603344A; CA3006337A1; EP3384087A1; BR112018010462A8; WO2017093250A1; CA3006337C; FR3044256A1; RU2700012C1; EP3384087B1; BR112018010462A2; FR3044256B1; CN108603344B; ZA201803517B

Abstract

The present invention relates in particular to a multilayer security element (2), which comprises a transparent or translucent planar mounting (21), characterised in that one of the opposing faces of said mounting (21) is coated with the following consecutive layers: a) a layer with variable optical effect (22), i.e. which, under observation of the mounting (21), provides at least one change of appearance which is visible to the naked eye, in accordance with the observation conditions; b) a dark opaque layer (23) which has at least one slit (230); c) a semi-reflective layer (24), i.e. which is reflective when the mounting (21) is observed under reflected light, and which is transparent when the mounting is observed by transmission, said semi-reflective layer (24) being provided at least opposite one portion of said slit (230); d) a visible layer (25), i.e. which is visible under reflected light as well as by transmission, provided at least vertically in line with the one or more regions in which the semi-reflective layer (24) is provided.

Description

The present invention relates in particular to a multilayer security element (2), which comprises a transparent or translucent planar mounting (21), characterised in that one of the opposing faces of said mounting (21) is coated with the following consecutive layers: a) a layer with variable optical effect (22), i.e. which, under observation of the mounting (21), provides at least one change of appearance which is visible to the naked eye, in accordance with the observation conditions; b) a dark opaque layer (23) which has at least one slit (230); c) a semi-reflective layer (24), i.e. which is reflective when the mounting (21) is observed un der reflected light, and which is transparent when the mounting is observed by transmission, said semi-reflective layer (24) being provided at least opposite one portion of said slit (230); d) a visible layer (25), i.e. which is visible under reflected light as well as by transmission, provided at least vertically in line with the one or more regions in which the semi-reflective layer (24) is provided.

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La presente invention se rapporte notamment a un element de securite (2) multicouche, qui comporte un support plan et transparent ou translucide (21), caracterise par le fait que l'une des faces opposees de ce support (21) est revetue des couches successives suivantes : a)une couche a effet optique variable (22), c'est a dire qui, sous observation du support (21), menage au moins un changement d'aspect visuellement perceptible a l'oeil nu, en fonction des conditions d'observation; b)une couche opaque sombre (23) qui presente au moins un ajour (230); c)une couche semi-reflechissante (24), c'est a dire qui est reflechissante lors d'une ob servation du support (21) en lumiere reflechie, et qui est transparente lors d'une observation du support par transmission, cette couche semi-reflechissante (24) etant presente au moins en regard d'une partie dudit ajour (230); d)une couche visible (25), c'est a dire visible aussi bien en lumiere reflechie que par transmission, qui est presente au moins a l'aplomb de la (des) region(s) ou la couche semi-reflechissante (24) est presente.

SECURITY ELEMENT AND DOCUMENT

FIELD OF THE INVENTION

The present invention is directed towards a multilayer security element and to a security document such as a banknote containing the same.

TECHNOLOGICAL BACKGROUND OF THE INVENTION

Security documents and more particularly banknotes are protected by security features. Even if the number of detected counterfeits generally does not exceed a few units per million banknotes for most notes in circulation, the impact of counterfeiting on the image of the issuing country and even on the entire economy if counterfeiting becomes massive, may become a major problem.

To avoid the above, central banks endeavour to provide against counterfeiting and actively combat the problem, in particular by increasing the security level of their banknotes and keeping technologically ahead of fraudsters.

Counterfeit banknotes can be detected at different levels of their chain of use.

For example, this can be carried out at commercial banks collecting notes used by the public or by traders, but also at security centres sorting and returning notes back into circulation, and finally at central banks.

These banks are equipped with automated banknote sorting machines provided with sensors capable of detecting certain physical or electromagnetic properties (fluorescence and phosphorescence, presence of elements visible under infrared light, electrical conductivity, simple or coded magnetism), certain tracers with unique spectral signatures or other specific elements (response to stimuli or analysis of emissions after excitation). The physical integrity of a banknote and extent of soiling are also evaluated.

However, if this counterfeit money reaches these collecting centres, this means that it has been fraudulently used without being detected. It will therefore be understood that upstream detection of these counterfeits is preferable, and preferably by the first user of the banknote.

For this purpose, the most efficient means is to provide the document with protective features the functioning of which is intuitive, easily authenticated or at least not requiring additional equipment, so that via mere observation or else even touch, it is possible to determine whether or not it is a genuine document. In addition, these features, on which a user will focus to authenticate the document, must be sufficiently complex so that they cannot be easily reproduced by possible counterfeiters. The reliability of the security feature must therefore be guaranteed ab initio, but also over time.

There exist numerous security features known to the public at large and considered to be robust.

For example, mention can be made of a security thread. Since it is integrated at the time of manufacture of the paper, it is closely bound to the mass of fibres. Integration thereof may be of “embedded” type, in which case it is only visible in transparency.

However, current preference is given to so-called “window” integration whereby the thread may partly emerge onto the surface of the paper in the form of a set of windows. This type of thread construction also allows the pairing of properties of automatic machine-readability (ex. electric conductivity, magnetism) with features that can be authenticated by the naked eye in the windows. This allows observation via reflection of the emerging thread portions, and via transparency of the embedded portions. By reflection, it is meant the phenomenon whereby rays of incident light are reflected on the surface of the substrate.

Conventionally, the thread is produced from a transparent substrate and coated with a metal of aluminium type for example. This metal is vacuum deposited and forms an opaque layer. Some metal portions may optionally be removed from the substrate in the form of text, patterns or any other shape so that they become transparent thereby distinguishing themselves from their opaque environment when observed under transparency. This partial demetallisation technique is notably taught in document WO 92/ 11142 and is known under the trade name “ Cleartext”.

More recently, optically variable features have been associated with this type of structure. This is particularly described in document WO 03/061980 which proposes associating a liquid crystal layer having reflective colour-shifting effects with a partly cut-out opaque metal layer, thereby forming a visible “Cleartext” that can be recognised when viewed in transmission.

The use of vacuum deposited metal, and more particularly of aluminium, is widespread. When a metal is vacuum deposited, it is in zero oxidation state and maintains all the physical properties connected with this state such as resistivity or electrical conductivity. Particular use is made of vacuum deposit via evaporation, sputtering, chemical vapour deposit. The layer thus formed has the advantage of being very thin (in the order of a few nanometres), very shiny, reflective and opaque provided it is sufficiently thick. This thickness is measured by optical density. Usually this optical density must be higher than 2-2.5 for aluminium, to obtain the required opacity.

The disadvantage with these types of methods is that it is difficult at the metallisation step to modify the thickness of the layer. Therefore, if it is desired to form layers of different thicknesses to create adjacent opaque and semi-transparent regions, an additional step would be needed. This is described in particular in document WO 2004/ 014665.

To improve the level of security and to overcome the previously indicated constraints, the applicant proposes providing a multilayer security element that has an intermediate layer which, although it can be obtained with a technique other than vacuum metal deposit, is able to exhibit a reflective appearance when viewed in reflection, and transparent appearance when viewed in transmission.

SUMMARY OF THE INVENTION

The invention concerns a multilayer security element comprising a transparent or translucent planar substrate.

Therefore, according to the invention, one of the opposing surfaces of this substrate is coated with the following successive layers:

a) a layer with variable optic effect, i.e. which, when the substrate is viewed, affords at least one change in appearance visually perceived by the naked eye, depending on viewing conditions;

b) a dark opaque layer having at least one openwork;

c) a semi-reflective layer, i.e. that is reflective when the substrate is viewed in reflected light, and is transparent when the substrate is viewed in transmission, this semi-reflective layer being present at least partly facing part of said openwork;

d) a visible layer, i.e. visible both in reflected light and in transmission, being present at least in line with the region(s) containing the semi-reflective layer.

Other nonlimiting and advantageous characteristics of the invention are:

- said optically variable layer is semi-transparent, i.e. reflective when viewed in reflection and transparent when viewed in transmission;

- said semi-reflective and visible layers are devoid of openwork and occupy at least the same surface area as the total surface area of said opaque layer;

- said semi-reflective layer is devoid of openwork and occupies at least the same surface area as the total surface area of said opaque layer, whilst said visible layer is only present facing said at least one openwork of said opaque layer and over a total surface area that is smaller than that of said at least one openwork;

- said semi-reflective layer is only present facing said at least one openwork of said opaque layer and over a total surface area that is smaller than that of said at least one openwork, whilst the visible layer is devoid of openwork and occupies at least the same surface area as the total surface area of said opaque layer;

- said opaque layer comprises at least two openworks, said semireflective layer and the visible layer are devoid of openwork and occupy at least the same surface area as the total surface area of said opaque layer, this visible layer being formed of at least two contiguous regions of a first and second colour respectively, each colour extending opposite at least one openwork;

- said semi-reflective and visible layers each comprise at least one window, these windows being superimposed and extending in line with each openwork whilst being fully included in this openwork, and said semi-reflective layer inside said window comprises at least one semi-reflective region;

- said layer with variable optic effect has at least one openwork;

- the materials of the different layers are selected from the following list:

A/ layer with variable optical effect: ink with interference pigments, notably iridescent, or optically variable inks; optically variable magnetic inks; liquid crystal inks; vacuumdeposited optically variable layers; layers having diffractive or reflective structures; layers having lenticular micro-optical or lens systems; layers with photonic crystals;

B/ other layers: inks incorporating materials having conductivity, magnetism, fluorescence, phosphorescence, infrared-visibility properties; and

- the element is in the form of a thread or strip or patch of any shape.

The invention additionally concerns a security document integrating an element according to the preceding characteristic which, if it is a thread, is incorporated therein whilst emerging onto the surface of at least one of its visible faces in the form of at least one window. If it is a strip or patch, it is affixed either directly onto the substrate or onto a transparent window.

BRIEF DESCRIPTION OF THE DRAWINGS

Other characteristics and advantages of the invention will become apparent on reading the following description of one preferred embodiment of the invention. This description is given with reference to the appended drawings in which:

-Figure 1 is a simplified overhead view of a banknote incorporating a security element of the invention which here assumes the form of a strip:

-Figure 2 is a cross-sectional view of a portion of a security element conforming to a first embodiment of the invention;

-Figure 3 is an overhead view of the element in the preceding Figure, such as it is perceived by an observer when viewed in reflected light;

-Figure 4 is a similar view to the preceding Figure but depicting the element such as it is perceived by an observer in transmitted light, i.e. in transparency;

-Figures 5 to 7 are similar views to Figures 2 to 4, depicting a second embodiment of the security element;

-Figures 8 to 10 are similar views to Figures 2 to 4 depicting a third embodiment of the security element;

-Figures 11 to 13 are similar views to Figures 2 to 4 depicting a fourth embodiment of the security element;

-Figures 14 to 16 are similar views to Figures 2 to 4 depicting a fifth embodiment of the security element;

-Figures 17 to 19 are similar views to Figure 2 to 4 depicting a sixth embodiment of the security element.

For better clarity in all the Figures and in particular in the crosssectional views, the dimensions of the illustrated elements (length, width and thickness) are not drawn to scale or in accurate proportions relative to each other, for facilitated comprehension.

DETAILED DESCRIPTION OF THE INVENTION

Throughout the present patent application, including the claims, the following expressions have the definitions given below:

-layer with variable optical effect: this is a layer which, when viewed, affords at least one change in appearance visually perceived by the naked eye, depending on viewing conditions. This therefore comprises colour shifting effects by tilting, rotating the substrate, etc. It also comprises, but not limited thereto, the optical effects obtained for example with lenticular microoptical or lens systems, reflective or diffractive microrelief structures, effects of change in contrast, shine (changeover from a shiny appearance to a matt appearance, etc.).

-dark opaque layer (or “revealing layer”): this is a layer of sufficiently dark shade to absorb a large portion of illuminating incident rays. Ideally it is black, but it can also be dark blue, dark brown, etc.

- semi-reflective layer: this is a layer that becomes reflective when the substrate is viewed in reflected light and transparent when the substrate is viewed in transmission. In other words, it is a layer having the feature of only reflecting part of the light it receives, allowing the other part to pass. This feature is used for example in the field of optics to form a two-way mirror for example or anti-reflective glass. It can be obtained for example using a vacuum deposit technique, with such precision that it allows the choice of transmitted or reflected colours.

-visible layer: this is a layer that it visible both in reflected light and in transmission. It is advantageously coloured.

Figure 1 very schematically illustrates a security document, here a banknote, comprising a security element 2 in the form of strip that is incorporated therein whilst emerging onto the surface of at least one of its major visible faces in the form of at least one window, here three windows illustrated simply as an example.

According to the invention, the multilayer security element 2 comprises a transparent or translucent 21 planar substrate that may be in polyethylene terephthalate (PET) for example and is characterized by the fact that one of the opposing surfaces of this substrate is coated with the following successive layers:

a) a layer with variable optical effect 22, i.e. which, when the substrate is viewed, affords at least one change in appearance that can be perceived by the naked eye, depending on viewing conditions;

b) a dark opaque layer 23 having at least one openwork;

c) a semi-reflective layer 24, i.e. that becomes reflective when the substrate is viewed in reflected light and is transparent when the substrate is viewed in transmission, this semi-reflective layer being present at least facing part of said openwork;

d) a visible layer 25, i.e. visible both in reflection and in transmission, being present at least in line with the region(s) in which the semireflective layer is contained.

The following description will focus on the layers 22 to 25 of the security element 2 having optical properties, and not on the usual functional layers. By the expression “functional layers” it is meant layers such as the heat sealing varnishes on the surface of the element 2 and intended for good adhesion thereof to the fibrous paper mass forming the security document 1 and in which it is incorporated. It is also meant the complexing glues employed to secure the substrate to layers solely having an eye-pleasing or optical effect function, the protective (“ cover-forming”) polyethylene terephthalate or the protective varnishes if this cover is omitted. Finally, the proposed constructions do not expose automatic machine-readable layers, i.e. those read by sorting machines using electrical conductivity and simple or coded magnetism.

The security element therefore comprises a transparent or translucent planar substrate composed for example of a polymeric material such as polyethylene terephthalate that is coated, preferably on the same side, with superimposed layers having a preferable total thickness of less than 45 pm (layers of the invention and functional layers). These different layers are successively placed in position preferably via printing. This technique is particularly well suited for implementing the invention and, as in any industrial process, the application of this technique comes up against manufacturing limits and tolerances.

It is therefore to be understood in the present application that at least two layers or two patterns applied by printing and even using other techniques, when they are mark-positioned (registered), when they are edge-toedge (or contiguous), when fully in line with each other, etc... are theoretical terms valid in Figures, drawings and layouts but which in fact suffer from minimum positioning differences on implementation.

It is usual for example to find printing tolerances between two consecutive groups in the order of +/-0.15 mm whereas tolerances must be envisaged of at least +/-0.25 mm if using two different processes or two passes that are not aligned.

The terms employed therefore amount at best to objectives that are attained and at worst to obj ectives towards which it is strived to tend.

As variable optical effect, preferable use is made of a layer of iridescent-type interference inks or an optically variable ink (known under the acronym (“OVI”). Simply as examples, mention can be made of the inks “65E013V” and “63E021V” by SICPA or the inks “ SUNNOTE 24926” or “24927” by Sun Chemical.

Liquid crystal inks can also be used, in particular those in the LUMOGEN range by BASF. Liquid crystals are in the form of rods which on average remain parallel to one another. A distinction is made between three major phases: nematic, smectic and cholesteric.

The nematic phase is the least ordered, the molecules being merely aligned in parallel. The cholesteric phase is a helical arrangement of chiral molecules. The term continuous stack of planes is used, in each of which nematic order prevails.

In the formulation of a liquid crystal ink, a nematic phase is used (in the order of 95°/) to which a chiral dopant is added (in the order of 5°/q). The helical structure induced by the chiral dopant causes a light interference effect causing the change in colour of reflected light.

The reflected wavelength is dependent on helical pitch. This pitch can therefore be varied by proportioning the amount of dopant to modify colour effects in reflection.

An additional effect produced by liquid crystals is the circular polarisation of reflected (and transmitted) light. By means of a polarising filter is it is therefore possible to shut out some colours perceived in reflection.

As indicated above, the dark opaque layer is ideally black. It is needed to reveal the colour shifting effect of the aforementioned devices which by nature are semi-transparent.

When light passes through a liquid crystal structure superimposed over a dark opaque layer, it is the rays reflected by said structure that are chiefly visible (the others being absorbed by the underlying opaque layer). Therefore, the expected colour shifting effect is efficient. If, on the contrary, the opaque layer is lighter-coloured or even shiny, other wavelengths would be reflected and would perturb legibility of the expected colour of the liquid crystals.

For example, use can be made of the “ 67E023” ink range by SICPA or SUN CHEMICAL as nonlimiting examples.

According to other manufacturing modes, this ink could incorporate properties of conductivity, magnetism, fluorescence, phosphorescence, infrared visibility for example or any other tracer able to authenticate this layer.

For the semi-reflective layer, use can be made for example of the “ 67E060” ink range by SICPA or else the “SunNote Mirror” range by SUN CHEMICAL, or “Platinstar” or “Ultrastar” produced by FLINT.

It is also possible to use a mixture of silver nanoparticles, for example the “ METASHEEN” range by BASF associated with a nitrocellulose matrix and solvent mixture.

A certain number of advantages regarding the use of a semireflective ink, as opposed to vacuum deposit, are listed below.

First, since a semi-reflective ink is employed following after the other layers in the print process, it can be placed precisely in register relative to ίο the other inks, provided that the press is equipped with a sufficient number of printing groups in line. This provides a freedom of shapes that is impossible to obtain when using a process having several steps of vacuum deposit and demetallisation type.

In addition, using a printing technique, it is possible to vary the ink deposit with great ease and hence the opacity of the layer. This is particularly possible with photogravure but impossible with a vacuum deposit method where the target of deposit is pre-set in advance and determined over the entire web of film.

It is also possible to obtain numerous metal hues by using colouring agents or pigments in the semi-reflective ink. For example, this allows the obtaining of the following metallic shade effects: silver, gold, bronze, copper but also more standard hues: blue, red, green, those of a Pantone colour chart or others.

In one preferred embodiment, a printing screen can be used with this ink to obtain nuances of the semi-reflective appearance and additional leverage for action. For example, screens of circular dots can be used, or of any shape, or random or fixed lines with coverage rates ranging from 0 to 100%and preferably higher than 50%

Finally, the semi-reflective nature of the ink can be used for masking purposes. Since the opaque layer is dark, it may leave a black mark when the strip in inserted in the paper, that is visible from the opposite side of the substrate. This unsightly appearance is avoided when using the masking properties of the semi-reflective layer.

According to one preferred embodiment, this ink may incorporate properties of conductivity, magnetism, fluorescence, phosphorescence, infrared visibility for example, or any other tracer able to authenticate this layer.

The visible layer is preferably composed of an ink containing colouring agents or pigments providing a visible hue.

Advantageous use can be made of fluorescent, phosphorescent, magnetic, infrared-visible agents, etc., able to impart an additional level of security to this layer.

Embodiments of the invention will now be successively described that are illustrated in Figures 2 ef seq.

With reference to Figure 2, a substrate 21 in transparent plastic of PET type is coated on its inner surface with a semi-transparent optically variable layer 22. In this variant, the layer 22 is continuous, i.e. without any openwork.

Underneath layer 22 there is a black opaque layer 23 here having two openworks or recesses 230 of circular shape. This shape and the number of openworks can evidently differ. A semi-reflective layer 24 (continuous and without any openwork) covers layer 23 including the openworks 230 thereof. Finally, a coloured layer 25 covers the entirety of the semi-reflective layer 24.

In Figure 3, the element 2 can be seen through the substrate 21 at an angle of 90° (i.e. the viewer is normal to the inspected security element). In line with the optically variable layer 22 a first colour can be seen, e.g. green. By tilting the substrate to an angle of about 30°, the colour changes to blue for example. In line with the openworks 230, the optically variable layer 22 is transparent and the semi-reflective ink of layer 24 can be seen.

Next, in Figure 4, the element 2 can be seen in transparency, with notably a point light source behind the security element. In line with the openworks, the semi-reflective layer 24 appears as transparent and reveals the coloured layer 25.

According to one preferred embodiment, the semi-reflective layer 24 is selected from among metallic inks of silver or aluminium type, meaning that it is of discrete shade merging well into the shade of the paper. This is notably appreciable since, for a viewer, they are comparable with the openworks of conventional “Cleartext”. It is only by viewing these openworks in transparency that the colour effect is revealed.

In the variant in Figures 5 to 7, the layers 22 and 24 are identical to those in the preceding embodiment. The opaque layer 23 still has openworks 230 but this time having an oval contour.

On the other hand, the coloured layer 25 is only contained in the form of patterns here in the shape of a Greek cross and are arranged directly in line with the openworks230.

In the viewing mode shown in Figure 6, the semi-reflective layer 24 appears slightly metallised.

When the security element is viewed in transparency, as can be seen in Figure 7, the semi-reflective layer 24 becomes transparent and the coloured layer 25 can be seen in the form of two crosses.

In the embodiment depicted in Figures 8 to 10, layer 22 remains unchanged, as does layer 23.

The semi-reflective layer 24 is present in the form of patterns representing two Greek crosses. As for the coloured layer 25, it occupies the entire surface of the element.

Under these conditions and when viewing in reflection (Figure 9), the crosses of layer 24 are visible through the openworks 23 but appear against a background formed by layer 25.

Figure 10 illustrates the element 2 viewed in transparency. The crosses of layer 24 can still be perceived but in the colour of layer 25.

Figure 11 illustrates another variant of the security element 2 wherein two different coloured layers, referenced 25a and 25b, form layer 25.

The layers 22 and 24 are solid and occupy the entire surface area of element 2.

Layer 23 has two openworks 230 of rectangular shape. However, inside these openworks, there are several printed regions which first form the value “ 5000” and secondly the acronym “ OF”.

When viewed in reflection (Figure 12), inside the openworks 230, the value “5000” and acronym “OF” can be seen. The contour of these patterns then appears to have a metallised appearance characteristic of the semireflective layer 24.

In transparency (Figure 13), the region is separated into two with different colours which are those of the regions referenced 25a and 25b. Evidently, it can be envisaged to have recourse to more than two colours.

In Figure 14, the opaque layer 23 has openworks 230 of rectangular shape. The semi-reflective layer 24 also comprises openworks 241 arranged facing the openworks 230 and are entirely contained therein. In addition, inside these openworks 241, there are ink patterns 242 which together form the acronym “ FCO” seen in reflection through the substrate 21.

The layer 25 comprises two different colours 25a and 25b, with openworks 250 which are exactly superimposed over those 241 of layer 24.

In transparency, the letters “ FO” can be seen represented in two colours.

In the embodiment shown in the last Figures 17 to 19, the layer 22 comprises two openworks 220 having an oval contour.

The opaque layer 23 also comprises two oval openworks 230. These extend directly in line with the openworks220 and are entirely contained therein.

The semi-reflective layer 24 is only present in the form of two 5 Greek crosses entirely contained within the aforementioned openworks.

Finally, layer 25 is continuous and occupies the total surface area of the element.

When viewed in reflection (Figure 18), the opaque layer 23 is only partly visible through the openworks of layer 22, in the form of pairs of “brackets”. Layer 24 is visible in the form of the aforementioned crosses, whilst layer 25 surrounds these crosses and is “ framed” by the “ brackets”.

When the security element is viewed in transparency, as illustrated in Figure 19, the semi-reflective layer 24 becomes transparent and the coloured layer 25 can be perceived within which the aforementioned crosses are materialised.

Claims

1/6

FIG. 1

FIG. 2

1. Multilayer security element (2) comprising a transparent or translucent planar substrate (21), characterized by the fact that one of the opposing surfaces of this substrate (21) is coated with the following successive layers:

a) a layer with variable optic effect (22), i.e. which, when the substrate (21) is viewed, affords at least one change in appearance visually perceived by the naked eye, depending on viewing conditions;

b) a dark opaque layer (23) having at least one openwork (230);

c) a semi-reflective layer (24), i.e. that is reflective when the substrate (21) is viewed in reflected light, and is transparent when the substrate is viewed in transmission, this semireflective layer (24) being present at least facing part of said openwork (230);

d) a visible layer (25), i.e. visible both in reflected light and in transmission, being present at least in line with the region(s) containing the semi-reflective layer (24).

2/6

FIG. 7

230a

2. Security element (2) according to claim 1, characterized by the fact that said optically variable layer (22) is semi-transparent, i.e. reflective when viewed in reflection and transparent when viewed in transmission.

3/6

FIG. 10

3. The security element (2) according to one of claims 1 or 2, characterized by the fact that said semi-reflective (24) and visible layers (25) are devoid of openwork and occupy at least the same surface area as the total surface area of said opaque layer (23).

4/6

FIG. 12

4. The security element (2) according to one of claims 1 or 2, characterized by the fact that said semi-reflective layer (24) is devoid of openwork and occupies at least the same surface area as the total surface area of said opaque layer (23), whilst said visible layer (25) is only present facing said at least one openwork (230) of said opaque layer (23) and over a total surface area that is smaller than that of said at least one openwork (230).

5. The security element (2) according to one of claims 1 or 2, characterized by the fact that said semi-reflective layer (24) is only present facing said at least one openwork (230) of said opaque layer (23) and over a total surface area that is smaller than that of said at least one openwork (230), whilst the visible layer (25) is devoid of openwork and occupies at least the same surface area as the total surface area of said opaque layer (23).

6. The security element (2) according to one of claims 1 or 2, wherein said opaque layer (23) comprises at least two openworks (230), characterized by the fact that said semi-reflective layer (24) and the visible layer (25) are devoid of openwork and occupy at least the same surface area as the total surface area of said opaque layer (23), this visible layer (25) being formed of at least two contiguous regions of a first and a second colour (25a; 25b) respectively, each colour extending opposite at least one openwork (230).

7. The security element (2) according to one of claims 1 or 2, characterized in by the fact that said semi-reflective (24) and visible (25) layers each comprise at least one window (241, 250), in that these windows are superimposed and extend in line with each openwork (230) whilst being fully included in this openwork ( 230), and in that said semi-reflective layer (24) inside said window (241) comprises at least one semi-reflective region (242).

8. The security element (2) according to one of the preceding claims, characterized by the fact that said layer with variable optic effect (22) has at least one openwork.

9. The security element (2) according to one of the preceding claims, characterized by the fact that the materials of the different layers are selected from the following list:

A/ layer with variable optic effect (22): ink with interference pigments, notably iridescent, or optically variable inks; optically variable magnetic inks; liquid crystal inks; vacuum-deposited optically variable layers; layers having diffractive or reflective structures; layers having lenticular micro-optical or lens systems; layers with photonic crystals;

B/ other layers: inks incorporating materials having conductivity, magnetism, fluorescence, phosphorescence, infrared-visibility properties.

10. The security element (2) according to one of the preceding claims, characterized by the fact that it is in the form of a thread or strip or patch of any shape.

11. Security document (1) such as a banknote, characterized by the fact that it integrates an element (2) according to the preceding claim which, when it consists in a thread, is incorporated therein whilst emerging onto the surface of at least one of its visible faces, in the form of at least one window (20) in

10 a strip or patch.

12. Security document (1) such as a banknote, characterized by the fact that it integrates an element (2) according to the preceding claim which, when it consists in a strip or patch, is applied thereto or onto a transparent window

15 contained therein.

6/6

FIG. 17