EP1778501A2

EP1778501A2 - Security element comprising a support

Info

Publication number: EP1778501A2
Application number: EP05770248A
Authority: EP
Inventors: Manfred Heim; Jürgen Ruck; Theodor Burchard
Original assignee: Giesecke and Devrient GmbH
Current assignee: Giesecke and Devrient Currency Technology GmbH
Priority date: 2004-08-12
Filing date: 2005-08-08
Publication date: 2007-05-02
Anticipated expiration: 2025-08-08
Also published as: BRPI0515003A; EP1778501B2; CA2577208A1; CA2577208C; WO2006018171A2; WO2006018171A3; AU2005274464A1; ES2428360T3; RU2007108437A; AU2005274464B2; AU2005274464C1; PL1778501T3; PL1778501T5; EP1778501B1; MX2007001545A; ES2428360T5; US20070246933A1; RU2381907C2

Abstract

THE invention relates to a security element (20) for securing antifalsification papers, valuable documents and the like, comprising a support (22). The security element is characterized in that the support (22) is provided with an authenticity feature (24, 26) which gives a first optical impression in transmitted light and which gives a second optical impression, significantly different from the first optical impression, in incident light and against a defined and easily accessible background.

Description

Security element with carrier

The invention relates to a security element for securing security papers, documents of value and the like with a transparent or translucent carrier. The invention further relates to a safety arrangement with such a security element as well as a correspondingly equipped security document.

Transparency windows in bank notes have long been known in the field of polymer notes. Providing a banknote with a see-through window on its own, however, does not yet provide additional counterfeit security for the note. Therefore, various security features have been proposed for see-through windows and partly also converted into banknotes.

For example, document WO 98/15418 A1 describes a self-verifying banknote made of a flexible sheet of a plastic substrate with identification marks. The self-verifying banknote has a transparent window area which contains a self-verification means for checking a security element arranged in a laterally spaced-apart area of the sheet. The self-verification takes place in that the window area is brought into register with the security element by bending or folding the sheet and the security element and the self-verification means cooperate there in a suitable manner in order to authenticate the banknote.

Frequently and to an even greater extent, the safety features for see-through windows are designed in such a way that more or less complicated aids are required for checking the authenticity of the security feature arranged in the window. Typically, for authenticity testing, external UV lamps, polarization filters, Moire filters or even Laser sources needed to shine through the see-through window to verify the security feature.

However, complicated tools are not always available and the authenticity check that is performed is often relatively time consuming. The user already feels that a test lasting several seconds is time-consuming and annoying. The authenticity check is then completely dispensed with in many cases, so that the protective effect of the security feature runs into the void.

Based on this, the object of the invention is to specify a generic security element which avoids the disadvantages of the prior art. In particular, the security element should be difficult to replicate and can be tested for authenticity with simple aids available almost everywhere.

This object is achieved by the security element having the features of the main claim. A security arrangement with such a security element and a corresponding security document are specified in the independent claims. Further developments of the invention are the subject of the dependent claims.

According to the invention, the transparent or translucent carrier of the security element is provided with a mark of authenticity which transmits a first optical impression in transmitted light and conveys a second optical impression in reflected light in front of a predetermined and easily accessible background first optical impression signi¬ fikantly different. This allows a simple and fast authenticity check, in which the security element is initially viewed in transmitted light and then held in front of a predetermined background. If the second optical impression differs gravely from the first optical impression, or even new structures or optical effects appear, the banknote can be evaluated by the user as genuine.

The authenticity mark appears in transmitted light with advantage structureless, transparent or translucent, and colorless. Compared with such an inconspicuous appearance, a different visual impression can be perceived particularly easily.

In the incident light in front of the predetermined background, the authenticity mark then preferably appears with a defined color impression. The authenticity mark can appear over the entire surface with a uniform color or with different colors, which can also form a pattern. Preferably, the defined color impression is in the form of patterns, characters or codes, such as in the form of the denomination of a banknote.

In other designs, the authenticity mark is not completely colorless in transmitted light, but appears structureless, transparent or translucent, and with a first defined color impression. In reflected light in front of the vorbe¬ certain background, the authenticity mark then appears advantageous with a second defined color impression, with hue and / or color intensity of the second color impression significantly different from the first color impression. The second defined color impression is preferably in the form of patterns, characters or codes.

While the variants described hitherto convey an unobtrusive, structureless impression in transmitted light, according to a further design variant, it is provided that the authenticity mark in the transmitted light pattern, Shows signs or encodings. Preferably, the appearance or the information represented by the patterns, characters or codes in the reflected light change significantly before the predetermined background or they disappear completely.

In all configurations, a printing layer can additionally be provided which, in the reflected light or transmitted light, together with patterns, symbols or codings of the authenticity mark, gives overall information. When changing from transmitted to reflected light observation or from reflected light to transmitted light viewing, the overall information may appear or disappear, or it may be altered, in particular supplemented.

As an alternative or in addition to a change in hue and / or color intensity, the authenticity mark can exhibit an optically variable effect in incident light in front of the predetermined background. In this case, it may be, for example, a color-shift effect dependent on the viewing angle, which conveys to the viewer a color impression which changes with the viewing direction. Also diffraction effects, scattering effects, in particular deriving from a matting, and refractive effects, in particular caused by microlenses and / or micromirrors, come into question.

The predetermined and easily accessible background may in particular be a highly reflective, in particular a metallic surface, a colored or uncolored plastic or glass plate, a strongly absorbing, dark surface, or a self-luminous source of polarized light, in particular an LCD display device, be. All of these background types are abundant in the ordinary environment and are therefore practically table everywhere without further effort to authenticate the Sicherheits¬ elements available.

In a preferred embodiment of the security element according to the invention, the authenticity mark contains a linearly polarizing layer and a phase-shifting layer. The phase-shifting layer can be formed in particular by a birefringent or an optically active layer.

The linear polarizing layer is preferably effective in the entire visible spectral range, but it may also have polarizing properties only in a partial region of the visible spectrum. The linearly polarizing layer can be formed by a layer applied to the transparent or translucent carrier, by a film bonded to the transparent or translucent carrier, or by the transparent or translucent carrier itself.

In order to achieve a sufficient difference of the optical impression, it has proven to be advantageous if the phase-shifting layer generates an optical phase shift of one tenth of a visible wavelength or more, at least in a wavelength range from the visible spectral range.

In a variant of the invention, the phase-shifting layer is formed by the transparent or translucent carrier itself, a separate phase-shifting layer can then be dispensed with. However, a higher flexibility of the design is achieved if the phase-shifting layer is formed by a separate layer applied to the transparent or translucent carrier. As materials for the phase-shifting Layer, in particular oriented liquid crystal layers offer. The phase-shifting layer and / or the linearly polarizing layer are expediently in the form of patterns, characters or codes.

In another, likewise preferred embodiment, the authenticity mark contains one or more layers of liquid-crystalline material, in particular of cholesteric liquid-crystalline material. The liquid crystal layers are transparent in transmitted light and substantially colorless, but appear in front of a strongly absorbing dark background with intense colors. On top of this they generate a color shift effect when the security element is tilted sideways from the vertical, which can change from a long-wave to a shorter-wave color impression, or vice versa, from a short-wave to a longer-wave color impression, depending on the design. The liquid crystal layers are also advantageous in the form of patterns, characters or codes.

According to a further advantageous embodiment, the authenticity mark contains a transparent thin-film element with an absorber layer and a dielectric spacer layer arranged between absorber layer and transparent or translucent carrier. The absorber layer and / or the dielectric spacer layer may be in the form of patterns, characters or codes.

In all the embodiments described, the authenticity mark of the security element according to the invention can contain a transparent, flat diffraction structure. In this case, the diffraction structure advantageously has an embossed structure arranged on the support, which in an inventive variant is provided with a high-indexing coating. Instead of the high-refractive coating, it is also possible to use a transparent thin-film element be applied to the embossed structure of the type described above. When viewed in incident light in front of the predetermined background, the color impression and the color shift effect of the thin-film element then appear in addition to the diffraction pattern of the diffraction structure.

The invention also includes a security arrangement for securing security papers, documents of value and the like, which has, in addition to a security element of the type described above, a verification element which provides the predetermined background for viewing the security element in incident light. In one variant of the invention, the verification element has a highly reflective, in particular metallic area, which can be formed in particular by a further metallized security element, such as a security strip or a patch. In another variant of the invention, the verification element has a strongly absorbing, dark surface area. This absorbing area can also be provided with further security features, for example a magnetic coding.

If a security document is equipped with such a security arrangement, the authenticity check can always be carried out with the verification element of the security arrangement. In a special embodiment, it is provided that damage-free testing of the authenticity symbol of a security arrangement can be carried out exclusively with a verification element of a security arrangement arranged on another security document. The user is then forced to carry out the authenticity check, a second similar Sicherheitsdo¬ document to hand. The invention further includes a security document, such as a security paper, value document or the like, with a security element or a security arrangement of the type described. In the latter case, the authenticity flag and the verification element are geometrically arranged on the security document in such a way that the authenticity flag is determined by Bie¬ gen or folding the security document on the verification element can be brought.

The security document advantageously has a paper or plastic substrate. The authenticity feature is preferably arranged in or over a window area or a continuous opening of the security document. If the security document has a plastic substrate, then the authenticity mark is advantageously applied over a transparent or translucent, in particular unprinted, area of the transparent or translucent plastic substrate.

In the case of a paper substrate, the mark of authenticity is preferably applied over a continuous opening of the paper substrate or introduced paper-like in such an opening. The continuous opening can be produced during papermaking without a sharp boundary edge of its edge region, so that a characteristic deckle edge is formed, which can not be formed by cutting or punching.

The security document represents, in particular, a security paper or a value document, such as a banknote, a check, an identity card, a document or the like. Further embodiments and advantages of the invention will be explained below with reference to the figures, in the representation of which a representation true to scale and proportion has been dispensed with in order to increase the clarity.

Show it:

Fig. 1 is a schematic representation of a banknote with a

See-through area over which a security element according to the invention is arranged,

2 shows the layer structure of a security element according to an exemplary embodiment of the invention in cross section,

Fig. 3 to 7 sectional views of security elements for further

Embodiments of the invention,

8 shows the authenticity check of a banknote provided with two security elements according to FIG. 4 against a metallic background, FIG.

9 shows a bank note having a security arrangement according to the invention with a security element according to FIG. 4 and a verification element formed by a security strip, FIG.

10 and 11 are sectional views of security elements according to further embodiments of the invention, 12 shows a bank note having a security arrangement according to the invention with a security element according to FIG. 10 or 11 and a verification element formed by a dark area area, FIG.

13 and 14 are sectional views of security elements according to further embodiments of the invention,

15 is a banknote with a security element according to yet another embodiment in plan view,

16 shows a cross section through the banknote and the security element of FIG. 15 along the line XVI-XVI, FIG.

17 shows a banknote with a security element according to a further exemplary embodiment in a plan view,

18 shows a cross section through the banknote and the security element of FIG. 17 along the line XVIII-XVIII, and FIG

FIGS. 19 and 20 show two banknotes with security elements according to the invention according to further exemplary embodiments of the invention in a top view.

The invention will be explained below using the example of a banknote. FIG. 1 shows a schematic representation of a banknote 10 with a through-view area 12 in a lateral subregion of the note. The transparent area 12 can be, for example, a continuous opening or a transparent partial area of the banknote 10. In or above this review Rich 12 is an inventive transparent security element 14 an¬ ordered.

When the banknote 10 is viewed in transmitted light, the security element 14 gives a first visual impression, in the exemplary embodiment the impression of a structureless and substantially colorless transparent area. In other embodiments, the security element can also be designed in such a way that it already has a slight coloration with a defined color impression in transmitted light throughout the entire surface.

If the banknote 10 with the security element 14 is held against a background of the predetermined type, then the security element 14 imparts a second optical impression, which differs significantly from the first optical impression. This clear change of appearance can be used for the authenticity of the bill. As will be explained in more detail below, the color impression, ie hue or color intensity of the security element 14, changes drastically during the transition from transmitted light to reflected light, or the patterns, characters or codes appear or disappear, or it appears an optically variable effect not recognizable in transmitted light, such as a color shift effect or a viewing angle-dependent diffraction pattern.

2 shows the layer structure of a security element 20 according to a first embodiment of the invention. The security element 20 of FIG. 2 has a carrier layer 22 of a transparent film, onto which a phase-shifting layer 24 and a linearly polarizing layer 26 are applied. The main axis of the phase-shifting layer 24 is rotated by at least 10 °, in the exemplary embodiment by 45 °, against the polarization direction of the linearly polarizing layer 26. The phase shift For example, layer 24 may be formed from a birefringent or optically active material, such as a liquid crystalline material, in the nematic or smectic phase, for example.

In transmitted light, the security element 20 appears transparent and structureless. On the other hand, when viewed in front of a highly reflective background such as a metal surface or the like, it shows distinct colors whose intensity and hue can be varied widely over the optical properties of the phase shifting layer 24 and the linear polarizing layer 26.

In the exemplary embodiment, the layer 26 has linearly polarizing properties over the entire visible wavelength range. The phase-shifting layer 24 used is a birefringent layer whose layer thickness and difference between the refractive indices of ordinary and extraordinary radiation in the exemplary embodiment is selected such that it is λ / 4 for red light with λ = 640 nm Layer represents. Red light is then linearly polarized by the layer 26, and the linearly polarized light undergoes an overall phase shift of 90 ° when passed twice through the layer 24 and intermittently reflected on the metallic background, so that the returning light from the linearly polarizing layer 26 is blocked. If white light is incident on the security element, the returning light, after passing through the security element twice, lacks a large portion of the red light, so that the security element appears in a characteristic blue hue. In an analogous manner, by selecting the birefringent properties of the layer 24 or by selecting the layer thickness thereof, different color effects can be produced. In the case of the security element 30 of the exemplary embodiment shown in FIG. 3, the linearly polarizing layer 26 is applied to a transparent carrier foil 32 with birefringent properties, so that a separate phase-shifting layer can be dispensed with.

FIG. 4 shows a security element 40 according to a further embodiment of the invention, which basically is constructed like the embodiment of FIG. 2. In contrast to the embodiment shown there, the phase-shifting layer 44 in FIG. 4 is present only in regions in the form of a coding, for example in the form of a lettering or a symbol. In transmitted light, the entire surface of the security element appears colorless and structureless. In front of a highly reflective background, the visual impression does not change in the recessed areas 46, while the areas in which the phase-shifting layer 44 is applied will light up in color and make the coding visible.

FIG. 5 shows a further variant of the security element of FIG. 2, in which a phase-shifting layer 44 of liquid-crystalline material is applied to a carrier foil 34 with linearly polarizing properties. As in the embodiment of FIG. 4, the phase-shifting layer 44 is applied only in regions in the form of a coding. In this variant, the separate linear polarizing layer is dispensable, since this function is already taken over by the carrier film 34. Suitable linearly polarizing films are commercially available. Production methods for wavelength-selective polarizing films are described, for example, in the document WO 2004/009373, the disclosure content of which is included in the present application in this respect. Another modification is shown in FIG. The security element shown there contains two interconnected foils. The linearly polarizing carrier foil 34 is connected to a second phase-shifting foil 36 of suitable layer thickness. The second film 36 may be made of PET or polypropylene, for example. In order to achieve the desired effect, care must merely be taken that the main axis of the double-refractive-index film 36 and the axis of the linearly polarizing film 34 are tilted relative to one another.

FIG. 7 shows a further variant of a security element according to the invention. In this case, a plurality of phase-shifting layers 44 A and 44 B having different optical properties are applied to a linearly polarizing carrier film 34. The layers 44A, 44B may be formed, for example, by liquid crystal layers having a different orientation direction. In this way, multicolor encodings can be realized during the verification. It goes without saying that it is also possible to use more than two different phase-shifting layers, and that the other configurations described can also be provided with multi-colored verification features in an analogous manner.

The authenticity check of a banknote provided with security elements 40 is illustrated in FIG. The banknote 50 has two similar security elements 40-1, 40-2 applied in transit areas of the banknote, in which the phase-shifting layer 44-1 or 44-2 is in each case in the form of the denomination of the banknote as a number sequence "10" In transmitted light, the security elements appear structureless and inconspicuous, the coded number sequence can not be recognized This is indicated in the right-hand security element 40-1 of the figure by the dashed representation of the number sequence 44-1 in Fig. 8, a part of the note in front of a 5, the regions of the security element 40-2 provided with the phase-shifting layer 44-2 appear as a clearly visible colored lettering "10" due to the effects described above.

The verification can also be carried out with a non-metallic good reflector. Smooth, colored plastic plates or smooth, colored glass plates are particularly well suited, but also simple, undyed glass or plastic plates can be used. The conspicuousness of the features can be further increased if behind the transparent glass or plastic plates a dark background is arranged.

A further possibility is the verification of the security elements by means of LCD display devices, such as are widely used as computer monitors, high-quality television sets and displays in a large number of portable devices from the field of consumer electronics. Such LCD display devices emit linearly polarized light, so that the security elements can also be verified by being held on or in front of an LCD display device or placed on the display.

The security elements described above use as a verification element in each case a separate, for example, metallic background, as it is found everywhere in the environment. The examination of the security element can therefore be carried out by anyone quickly and without any special effort. However, a metallic verification element may also be arranged on the banknote itself, as shown in the embodiment of FIG. 9. The banknote 60 of FIG. 9 includes a security element 40 of the type described with reference to FIG. 4 and a metallized security strip 62. The security strip 62 is typically provided with further security features, not shown in the figure, such as negative writing, optically variable diffraction structures. a magnetic coding or the like equipped. The security element 40 and the security strip 62 are arranged mirror-symmetrically to the center line 64 of the banknote 60, so that the security element 40 comes to lie on the security strip by folding the banknote around this center line. The banknote 60 can therefore be checked for authenticity by simple folding, without the need for external verifying means. It goes without saying that the check of the banknote 60 can also take place with a security strip applied to another banknote.

The difference between the two optical impressions of the security element in transmitted and reflected light observation can also be ensured in other ways. 10 shows the basic layer structure of a safety element 70, which has one or more layers of liquid-crystalline material. The security element 70 contains a transparent carrier 72, for example a smooth PET film of good surface quality, on which one or more layers 74 of a cholesteric liquid crystal material are applied. Between the liquid crystal layers 74, it is possible to provide alignment layers and / or adhesive layers 76 which serve to align the liquid crystals in the liquid crystal layers or the compound of the individual liquid-crystalline layers and compensate for unevenness.

Seen in transmitted light, the security element 70 appears colorless and structureless. If, on the other hand, it is exposed to a strongly absorbing dark background, Viewed background, the liquid crystal layers produce an intense colored impression. In addition, when viewed in front of a dark background and changing the viewing angle, a color shift effect becomes visible, which typically changes from a long-wave to a shorter-wave color impression, for example from green to blue, but also from a short-wave to a longer one when a plurality of liquid crystal layers are combined wavy color impression can change, such as from blue or purple to red.

The liquid crystal layers 74 may also be present only in regions in the form of a lettering or a symbol or they may have corresponding information-containing recesses. The coded information then emerges analogously to the situation described above only when the security element 70 is viewed in front of the predetermined absorbing background.

11 shows a security element 80 according to a further embodiment of the invention. The security element 80 has a transparent carrier 82 which is provided with a mark of authenticity in the form of a transparent thin-film element 84. The thin-film element 84 consists of an ultrathin dielectric spacer layer 86, for example a SiCh layer 200 nm to 500 nm thick, and an absorber layer 88 passing through a 4 nm to 20 nm thick metal layer of chromium, iron , Gold, aluminum or titanium can exist.

Seen in transmitted light, the security element 80 appears transparent and colorless. In contrast, due to interference effects in the sub-layers of the thin-film element 84, before a strongly absorbing background occurs a strong color effect. In addition, upon tilting of the security element 80, a clearly perceptible color shift effect results.

As shown in FIG. 11, the dielectric spacer layer 86 or, preferably, the absorber layer 88 can also be present only in regions and form a lettering or another coding. The strong color effect and the Farbkippeff ect then occur only in the areas in which the absorber layer 88 is present.

The designs described with reference to FIGS. 10 and 11 each require as a verification element a strongly absorbing, dark background, which is readily available in the usual environment. In this variant too, however, a verification element can be arranged on the banknote itself, as shown with reference to FIG. 12.

For this purpose, the banknote 90 has a security element 92 which is arranged in a see-through region and which may be formed, for example, like the liquid-crystal-layer security element 70 of FIG. 10 or the thin-film security element 80 of FIG. On the backside of the banknote 90, a dark, absorbent area 94 is arranged. The area region 94 does not have to be structureless; it can contain, for example, a darkly held portrait or another graphic motif in dark hues. Like the security strip 62 of FIG. 9, the area region 94 can also be equipped with further security features.

In transmitted light, the see-through area of the banknote 90 shows a colorless and structureless appearance. If the banknote 90 is folded along its middle line 96 and the dark area 94 is folded under the security element 92, the color effect of the security element clearly appears out. In the exemplary embodiment, the numerical sequence "10" appears in clear, luminous colors In addition, when the folded banknote 90 tilts sideways, a color-shift effect occurs, the expression of which depends on the exact design of the security element 92.

In the case of the security element 100 of the embodiment shown in FIG. 13, in addition to a thin-film element with a color-shift effect, a planar diffraction structure, such as a hologram or a hologram-like diffraction structure, is additionally provided. For this purpose, a likewise transparent embossing lacquer layer 104 is applied to a transparent carrier foil 102 and a desired diffraction structure 106 is embossed.

A thin-layer element 108, whose layer structure, as in FIG. 11, comprises an ultrathin dielectric spacer layer 110 and an absorber layer 112, is further applied to the embossing lacquer layer 104. The relief of the diffraction structure 106 continues in this case in the thin-film element 108 vertically upward. The absorber layer 112 is only partially present in this exemplary embodiment in order to provide the security element 100 with a lettering or another coding.

In transmitted light, the security element 100 is perceived as a transparent, structureless area, neither the color-shift effect of the thin-film element 108 nor the diffraction pattern of the diffraction structure 106 noticeably appear. On the other hand, if the security element 100 is viewed in reflected light against a dark, strongly absorbing background, then the diffraction structures 106 clearly emerge in addition to the already described color effect and the color shift effect of the thin-film element 108 and allow the authenticity check of the security element 100 to be ver¬ seen document. Since the security element 100 is transparent in transmitted light rent, it can not be readjusted with the aid of commercially available dye-tilting films or by printing layers with oil-tipping pigments.

Instead of the diffraction structure, the security element can also be provided with a matt structure or a refractive structure of micromirrors or microlenses.

Fig. 14 shows another embodiment of the invention. In this case, the security element 120 has a transparent carrier foil 122 with a transparent embossing lacquer layer 124 and a high-indexing coating 126. Embossed in the embossing lacquer layer 124 is a desired diffraction structure 128, for example a hologram or a hologram-like relief structure. The security element 120 essentially appears as a colorless and structureless see-through window when viewed through. In reflected light against a dark background, the diffraction structure 128 clearly emerges and thus enables the authentication of the document provided with the security element 120.

The security elements described so far usually show a rather inconspicuous visual impression in transmitted light and reveal new features when viewed against a predetermined background. According to the invention, features which are visible in transmitted light can also disappear on application to a suitable background, or information which is visible in the transmitted light can be supplemented or altered in another way when viewed in front of a suitable background. Exemplary embodiments will be explained below with reference to FIGS. 15 to 20. FIGS. 15 and 16 show a banknote 130 with a security element 132 according to the invention, FIG. 15 showing the banknote in top view and FIG. 16 a section through the banknote and the security element along the line XVI-XVI. The security element 132 includes a transparent foil strip 134 which is provided with a black imprint 136, here in the form of the number "10", and a liquid crystal layer 138 applied above it The black imprint 136 may be on the top, as in FIG A see-through area of the banknote, here a continuous opening 140, is completely covered by the film strip 134.

When viewing the banknote against a light background, the black imprint 136 within the see-through area 140 is clearly visible, while disappearing for the viewer when placing the banknote on a dark, especially black background due to the then lack of contrast. After laying, the entire opening 140 appears on the whole surface with a uniform characteristic shimmering, which results from the liquid crystal layer 138.

A further variant is shown in FIGS. 17 and 18, wherein FIG. 17 shows a plan view of a banknote 150 with a security element according to the invention and FIG. 18 shows a section through the banknote and the security element along the line XVIII-XVIII. The banknote 150 was provided in the papermaking with through holes 152 and 156 with a characteristic deckle edge which is not replicable by cutting or punching.

Further, the bill is provided in a surrounding area of the first opening 152 with a black imprint 154, while the second opening 156 two spaced, formed by black imprints areas 158 connects. The openings 152 and 156 and the associated imprints 154 and 158 are covered by a transparent film strip 160 provided with a liquid crystal layer 162. It is understood that the black imprints 154 and 158 may be applied to the top or bottom of the film 160 instead of the banknote paper.

As an alternative to the black imprints, it is also possible to use a patch, e.g. applied by hot embossing, placed. Of course, this also applies to all other embodiments.

Against a light background, the openings 152 and 156 clearly stand out from the black imprints 154 and 158, respectively. When viewing against a dark, in particular black background, the viewing impression changes: the opening 152 and the print 154 then appear as a full-surface square, the opening 156 together with the print 158 forms a continuous dark area. In addition, all of the dark surface areas each show the characteristic shimmering of the liquid crystal layer 162.

The designs illustrated in FIGS. 15 to 18 can be used to display or disappear, change or supplement information encoded in a security element during the background change.

19 shows a banknote 170 with a security element 172 of the type explained with reference to FIG. 17. The banknote 170 has four through openings 174 and five black printing areas 176, which in the embodiment show the desired information. The area of the openings 174 and the black printing areas 176 is covered with a transparent, liquid-crystal-coated film 178.

When viewed against a light background, the openings 174 appear bright, the black areas 176 dark, however, so that the Zif¬ succession is not recognizable as such. On the other hand, when viewed against a dark background, the regions 174 and 176 appear equally dark, so that the digit string "20" then clearly emerges as a whole.

Another effect is utilized in the embodiment of FIG. 20. The banknote 180 shown there has a see-through area 182 which is covered with a transparent film 184. The film 184 is provided in a partial area with a liquid crystal layer 186 in the left half of the numeral "8." Adjacent to the inspection area 182, a black imprint 188 in the right half of the numeral "8" is applied to the banknote paper. The region of the banknote containing the imprint 188 is additionally overprinted with a liquid crystal layer 190.

Against a light background, only the black imprint 188 can be seen on the banknote, which represents only a part of the overall information. The liquid crystal region 186, on the other hand, is hardly or not at all visible. Only when placed on a black background, the entire figure "8" appears due to the characteristic shimmering of the liquid crystals.

The liquid-crystalline material of the exemplary embodiments 15 to 20 may be, for example, in the form of pigments embedded in a binder matrix available. The liquid-crystal layers can also be completely or partially structured and formed, for example, in the form of hatching.

Claims

Patent claims

1. Security element for securing security papers, Wert¬ documents and the like with a transparent or translucent carrier, characterized in that the transparent or translucent carrier is provided with a mark of authenticity, which conveys a first optical impression in transmitted light and in reflected light before a vorbestimm¬ A second optical impression, which differs significantly from the first optical impression, is conveyed to the background and easily accessible background.

2. Security element according to claim 1, characterized in that the authenticity mark in the transmitted light appears structureless, transparent or translucent, and colorless.

3. Security element according to claim 1 or 2, characterized in that the authenticity mark appears in incident light in front of the predetermined Hinter¬ reason with a defined color impression.

4. Security element according to claim 3, characterized in that the defined color impression in the form of patterns, characters or Codierun¬ gene is present.

5. Security element according to claim 1, characterized in that the authenticity mark in the transmitted light appears structureless, transparent or translucent with a first defined color impression.

6. Security element according to claim 5, characterized in that the authenticity flag in reflected light against the predetermined background and appears with a second defined color impression, wherein color tone and / or color intensity of the second color impression differ significantly from the first color impression.

7. Security element according to claim 6, characterized in that the second defined color impression is present in the form of patterns, symbols or codes.

8. Security element according to claim 1, characterized in that the authenticity flag in transmitted light shows patterns, characters or codes.

9. Security element according to claim 8, characterized in that the appearance or the information content of the patterns, characters or codes of the authenticity mark significantly changed in reflected light before the vorbe¬ certain background or that the patterns, characters or codes completely disappear.

10. The security element according to claim 1, characterized in that a printing layer is provided which, in the light or transmitted light, together with patterns, symbols or codes of the authenticity mark, gives overall information.

11. A security element according to claim 10, characterized in that the total information when changing from transmitted to Auflichtbetrach¬ direction or from reflected to transmitted light viewing appears, disappears or changed, in particular supplements, is.

12. The security element according to at least one of claims 1 to 11, characterized in that the authenticity flag in the onset before the predetermined background shows an optically variable effect.

13. A security element according to claim 12, characterized in that as optically variable effect of one or more effects from the group Beu¬ tion effects, viewing angle-dependent color shift effects, scattering Ef¬ effects, especially from a matting resulting, and refractive effects, in particular of microlenses and / or Micromirrors caused, is used.

14. A security element according to at least one of claims 1 to 13, characterized in that the predetermined background is a highly reflective, in particular a metallic surface, or a colored or uncolored plastic or glass plate.

15. A security element according to at least one of claims 1 to 13, characterized in that the predetermined background is a selbst¬ luminous source of polarized light, in particular an LCD display device.

16. A security element according to at least one of claims 1 to 13, characterized in that the predetermined background is a strongly absorbing, dark surface.

17. The security element according to at least one of claims 1 to 16, characterized in that the authenticity mark contains a linearly polarizing layer and a phase-shifting, in particular birefringent layer.

18. A security element according to claim 17, characterized in that the linearly polarizing layer is effective in the entire visible spectral range.

19. A security element according to claim 17, characterized in that the linearly polarizing layer is effective only in a partial region of the visible spectrum.

20. A security element according to at least one of claims 17 to 19, characterized in that the linearly polarizing layer is formed by the transparent or translucent support itself.

21. The security element according to claim 17, characterized in that the phase-shifting layer generates an optical phase shift of one tenth of a visible wavelength or more, at least in a wavelength range from the visible spectral range.

22. Security element according to at least one of claims 17 to 21, characterized in that the phase-shifting layer is formed by the transparent or translucent carrier itself.

23. The security element according to claim 17, characterized in that the phase-shifting layer is formed by a layer applied to the transparent or translucent carrier, in particular an applied liquid-crystal layer.

24. Security element according to at least one of claims 17 to 23, characterized in that the phase-shifting layer and / or the linearly polarizing layer in the form of patterns, characters or Codierun¬ gene present.

25. A security element according to at least one of claims 1 to 16, characterized in that the authenticity mark contains one or more layers of liquid-crystalline material, in particular of cholesteric liquid-crystalline material.

26. The security element according to claim 25, characterized in that the one or more liquid crystal layers are in the form of patterns, characters or codes.

27. The security element according to claim 1, wherein the authenticity mark comprises a transparent or translucent thin-film element with a dielectric spacer layer and an absorber layer arranged between spacer layer and transparent or translucent carrier.

28. The security element according to claim 27, characterized in that the absorber layer and / or the dielectric spacer layer are in the form of patterns, characters or codes.

29. A security element according to at least one of claims 1 to 28, characterized in that the authenticity mark contains a flat diffraction structure.

30. The security element according to claim 29, characterized in that the planar diffraction structure has an embossing structure arranged on the support.

31. Security element according to claim 30, characterized in that the embossed structure is provided with a high refractive index coating.

32. The security element according to claim 27 and according to claim 30 or 31, characterized in that the transparent or translucent thin-layer element is applied to the embossed structure.

33. Security element according to at least one of claims 1 to 28, characterized in that the authenticity mark includes a matting, an array of microlenses or an array of micromirrors.

34. Security arrangement for securing security papers, documents of value and the like, with a security element according to one of claims 1 to 33 and a verification element which provides the vorbe¬ certain background for viewing the security element in Auf¬ light.

35. Safety arrangement according to claim 34, characterized in that the verification element has a highly reflective, in particular metallic surface area.

36. A security arrangement according to claim 35, characterized in that the verification element represents another metallized security element, such as a security strip or a patch.

37. The safety arrangement according to claim 34, characterized in that the verification element has a strongly absorbing, dark surface area.

38. Security arrangement according to claim 34, characterized in that a damage-free check of the authenticity mark of a security arrangement can be carried out exclusively with a verification element of a security arrangement arranged on another security document.

39. Security document, such as security paper, document of value or the like, having a security element according to at least one of claims 1 to 33.

40. Security document, such as security paper, document of value or the like, having a security arrangement according to at least one of claims 34 to 38.

41. Security document according to claim 40, characterized in that the authenticity mark and the verification element are arranged geometrically on the security document such that the authenticity mark can be brought about by the bending or folding of the security document via the verification element.

42. The security document according to claim 39, wherein the security document comprises a paper or plastic substrate.

43. Security document according to at least one of claims 39 to 42, characterized in that the authenticity feature is arranged in or over a window area or a through opening of the security document.

44. Security document according to claim 43, characterized in that the security document has a plastic substrate and the authenticity mark is applied over a transparent or translucent, in particular unprinted area of the plastic substrate.

45. Security document according to claim 43, characterized in that the security document has a paper substrate and the authenticity mark is applied over a continuous opening of the paper substrate.

46. A security document according to claim 43, characterized in that the security document has a paper substrate and the authenticity mark is introduced paper-mechanically into a continuous opening of the paper substrate.

47. Security document according to claim 45 or 46, characterized gekenn¬ characterized in that the through-opening is produced during papermaking without sharp boundary edge of its edge region.

48. Security document according to at least one of claims 39 to 47, characterized in that the security document is a security paper or a value document.