EP3339049B1 - Data carrier with luminescent regions - Google Patents

Description

The invention relates to a data carrier, in particular a value or security document, with a translucent substrate with a front side and a rear side and with luminescent areas arranged both on the front side and on the rear side.

Data carriers, such as value or identity documents, but also other objects of value such as branded items, are often provided with security elements for protection that allow the authenticity of the data carrier to be checked and which also serve as protection against unauthorized reproduction.

In this context, it has been known for a long time to use luminescent substances to secure value or identity documents. The presence of the luminescent substances can then be checked with the aid of a UV lamp, for example. For example, fluorescent mottled fibers, which usually consist of short fibers provided with a fluorescent coating, can be introduced into a security paper. The mottled fibers are invisible under normal lighting, but under UV lighting they are clearly visible due to their bright fluorescence, for example in red, green or blue, despite their small size. The printing of true-color luminescence images is also known, particularly in the passport area. The implementation usually takes place in ink-jet printing with special colors that are not visible in normal lighting and, when stimulated by UV light, show a color impression comparable to a classic picture, for example a portrait of the passport holder.

Also known are security features which are not or not completely visible when viewed from above, but only become recognizable when looking through, as shown for example in FIG WO 2012/113546 A2 .

Ink-jet fluorescent inks, which enable a forger to produce forgeries, have now become more readily available due to online trading in particular. Printing ink manufacturers also offer sometimes fluorescent colors intended for technical gadgets or brand protection.

WO-2013/091860-A1 describes a chemical approach to detect counterfeits with fake fluorescent colors. In WO 2014/082754 A1 normal and luminescent printing inks are arranged next to one another in such a way that, depending on the excitation conditions, an additional effect that the viewer can recognize is created.

WO 2014/076245 A1 uses differently colored luminescent line or point grids on different sides of a substrate to create a color change. WO 2004/050376 A1 creates different colors in certain areas through parallel excitation with visible and UV light. AU 2010 247 266 B2 increases the transparency of a paper substrate by applying a transparentizing agent. DE 10 2005 022 518 A1 uses a luminescent print over a watermark in the paper. In WO 2007/085808 A1 Partial images from different sides of the substrate, which can optionally be fluorescent, complement each other. The document shows the preamble of claim 1.

On this basis, the invention is based on the object of specifying a data carrier of the type mentioned at the beginning with an attractive appearance and a high level of protection against forgery.

This object is achieved by the features of the independent claims. Developments of the invention are the subject of the dependent claims.

One aspect of the present solution is to distribute a luminescence image in register on both sides of a translucent substrate and also to coordinate the substrate and the luminescence with one another. Both the excitation and the luminescence must be at least partially due to the Take place through the substrate, which usually has a very different opacity for excitation and luminescence. In addition to the register accuracy, which is difficult for a forger to achieve, the coordination - in particular for a page-dependently different luminescence - cannot be easily readjusted.

A data carrier according to the invention is defined in claim 1.

In the context of this description, luminescence is understood to mean in particular fluorescence and phosphorescence, but also up-conversion or the emission of feature substances with anti-Stokes behavior.

The terms front and back merely refer to the relative orientation of the two main surfaces of a data carrier. In principle, each of the main surfaces can be selected as the front side, in particular independently of further properties of the data carrier.

For the sake of completeness, it is pointed out that viewing in transparency is present when the excitation and viewing take place from different sides, in particular an excitation from the front for the viewer of the rear or an excitation from the rear for the viewer of the front. On the other hand, there is a view from above if the suggestion and the view are from the same side.

The first and second areas of luminescent material form a luminescent see-through register. The present luminescent see-through register produces, depending on the side, a different luminescence for the viewer in see-through.

The at least one parameter is selected in such a way that the luminescence register image can be recognized by the viewer as an image that is supplemented by the image components. In particular, the parameter is selected as a function of the area in such a way that a difference in the brightness values of the adjoining image components of the luminescence register image is reduced (compared to a difference in the brightness values without adaptation).

For the viewer, the luminescence register image is generated when looking through the front side, and when looking through the back side, a recognizable different luminescence comparison image is generated.

For a better differentiation of the luminescence images, the image generated through front-side excitation can be referred to as a luminescence register image. The image generated when viewed from the rear can be referred to as a luminescence comparison image. Corresponding For example, an image generated for the viewer in plan view when the front or rear side is stimulated can be referred to as a luminescence front side image or luminescence rear side image, respectively.

In particular, the luminescence comparison image can be used by the viewer to verify the side-dependency of the luminescent see-through register. The at least one parameter is preferably selected in such a way that the recognizable different luminescence comparison image used to verify the side-dependency of the luminescent see-through register is produced.

The luminescence comparison image preferably contains only a portion of the image from one of the two luminescent areas. Alternatively, in the luminescence comparison image, a difference in the brightness values of the image components of the two luminescent areas can be increased noticeably for the viewer.

Alternatively or additionally, the luminescent front image can serve the viewer to verify the side-dependency of the luminescent see-through register. The at least one parameter is preferably selected in such a way that the recognizable different luminescence front side image used to verify the side dependency of the luminescent see-through register is produced. The luminescent front side image then preferably contains only an image portion from one of the two luminescent areas. Alternatively, in the luminescence front side image, a difference in the brightness values of the image components of the two luminescent areas can be increased noticeably for the viewer.

The translucent substrate is preferably a fiber-based substrate, for example a paper substrate.

In preferred variants, the translucent substrate comprises a sub-area of reduced substrate thickness and / or at least one transparent sub-area.

If the translucent substrate is a paper substrate or if the translucent substrate comprises a paper layer, the partial area of reduced substrate thickness is advantageously formed by a watermark generated during the paper production of the paper substrate or the paper layer.

In another, likewise advantageous embodiment, the partial area of reduced substrate thickness is produced by physical removal of substrate material after the substrate has been produced. The removal can be done by means of a mechanical milling cutter or by means of a laser. It is particularly advantageous if the substrate material is subsequently removed from the sieve side of a substrate produced by means of a (dewatering) sieve. During production, the substrate lies with the sieve side on the sieve. The excitation opacity of the substrate is increased on the sieve side, i.e. it decreases (non-linearly) within the substrate from the sieve side to the opposite side. A removal of the substrate from the sieve side thus has a disproportionately strong effect as a reduction in the excitation opacity.

The partial area of reduced opacity can also be formed as a transparentized partial area of the substrate. In this case, the layer thickness in the reduced opacity sub-area is unchanged, but the transmission of the substrate material for visible light and / or UV radiation is locally increased. A transparentized partial area can be transparentized (luminescence-transparent) in the visible spectral range and / or in the spectral range of excitation, that is to say in particular in the IR or near UV range or UV range, be transparent (excitation-transparent). Such an increase in transmission can be generated, for example, by applying a transparent lacquer. The transparency agent can preferably be produced on the basis of a paint or a varnish. Alternatively, transparency by means of high-energy excitation radiation is also conceivable.

It is particularly advantageous that the partial area of reduced opacity is also arranged in register with the (first or second) luminescent area. A register-accurate generation of the front and back luminescent areas and the partial areas is only possible with high-quality printing machines or complex manual assembly of ink-jet prints and therefore makes re-adjustment considerably more difficult.

The first luminescent area preferably laterally adjoins the second luminescent area on two sides. The first luminescent area could completely surround the second luminescent area.

In a preferred embodiment, the transition (the boundary or the boundary line) between the two image components in the luminescence register image cannot be recognized by the viewer. The adjoining image components of the luminescence register image have the same brightness value and the same color tone for the viewer.

A boundary line between the two luminescent areas is advantageously followed by a non-luminescent area on one side or on both sides. The addition of the image components to the luminescence register image in perfect register is thus even better recognizable.

The boundary line between the two image parts (or areas) can preferably not be linear. A readjustment of the exact register arrangement is made even more difficult.

The (linear or non-linear) transition (the boundary or the boundary line) between the two image components in the luminescence register image can be recognizable for the viewer in a different embodiment. The adjoining image components of the luminescence register image then have the same brightness value and different color tones for the viewer.

The luminescence strength of the applied luminescent material can be adjusted by the layer thickness of the luminescent material and / or luminescent substance concentration in the luminescent material. If the luminescent material is applied in a rasterized manner, the rasterization, in particular the raster point size, can alternatively also be used. The luminescence strength of the luminescent areas of the front and back can be the same, but it is also possible for the luminescent areas of the front and back to have different luminescence strengths.

The substrate can be removed or made transparent from the side on which the luminescent material is subsequently applied. Alternatively, the substrate can be removed or made transparent from the opposite side (before or after the application of the luminescent material). In a further variant, the substrate is made transparent from both sides or substrate material is removed from both sides.

In further advantageous configurations, the luminescent areas of the front side and / or the luminescent areas of the rear side extend beyond the partial area of reduced opacity. In this way, the front side and the rear side can each show different luminescence images, for example, which contain an identical image part in the partial area of reduced opacity. The luminescent areas of the front side and the luminescent areas of the rear side are, however, also in this case advantageously matched to one another in the partial area of reduced opacity.

In an advantageous embodiment, the luminescent areas of the rear side and the front side contribute image components of different colors to the luminescent image.

The translucent substrate has a predetermined thickness in its basic state / area not changed in thickness / a third area. The opacity of the substrate depends (among other things) on the thickness of the substrate. The substrate is called translucent because it has a minimum opacity in the visible spectral range. A transmittance (T = I / I_0) of 0.1 to 0.9 can be regarded as translucent, the corresponding opacity value (O = 1 / T) is in the range from 1.11 to 10. The translucent substrate preferably exhibits luminescence -Opacity between 1.5 and 9, preferably between 2.1 and 5. The translucent substrate preferably has an excitation opacity between 1.25 and 10, preferably between 2.1 and 5. The excitation opacity is preferably greater than the luminescence opacity.

The translucent substrate can - before or after the application of the luminescent material - be provided with a transparent plastic film on one or both sides. To avoid misunderstandings, however, it is noted that a transparent substrate - even if it should be provided with non-transparent prints and / or coatings - is by no means a translucent substrate in the present sense.

The luminescent areas are advantageously not recognizable when viewed in visible light, so that the luminescent see-through register represents a hidden security feature that only appears when exposed to UV radiation.

A method for manufacturing a data carrier according to the invention is defined in claim 13.

In an advantageous embodiment, a paper substrate or a composite substrate with a paper layer is provided as the translucent substrate, and when the paper substrate or the paper layer is produced, a watermark is produced which forms the partial area of reduced opacity.

In another, likewise advantageous embodiment, the partial area of reduced opacity is produced by physical removal of substrate material after the substrate has been produced. This can be done in particular by laser ablation, for example with a CO ₂ laser or with the aid of a mechanical milling cutter.

Finally, according to a further advantageous embodiment, the partial area of reduced opacity can also be produced by applying a transparency agent, for example a transparent varnish.

Furthermore, it is basically also possible to create partial areas of different opacity through the use of UV blockers. For example, UV blockers can be arranged below the luminescent areas in a partial area on the front and back of the data carrier, so that a complete luminescence image is obtained only outside of these UV-blocked areas. According to a further embodiment, the UV blockers on the front and back can also be arranged laterally offset from one another. As a result, it can be achieved, for example, that the luminescence information in an overlap area of the opposing UV blockers is the same when checked from both sides and is different outside the overlap area. In principle, however, the use of UV blockers also has disadvantages, since the luminescence is further weakened by the UV blockers and they require an additional layer in the data carrier structure.

Further exemplary embodiments as well as advantages of the invention are explained below with reference to the figures, in the representation of which a representation true to scale and proportion was dispensed with in order to increase the clarity.

Fig. 1

schematisch eine Aufsicht auf eine erfindungsgemäße Banknote mit einem lumineszierenden Durchsichtsregister,

Fig. 2

einen Querschnitt durch die Banknote der Fig. 1 entlang der Linie S--S und das bei UV-Beaufschlagung von der Vorderseite her auf der Rückseite entstehende Lumineszenz-Registerbild,

Fig. 3a,b,c

das Lumineszenz-Registerbild und die entsprechend anregungs- und betrachtungs-seitenabhängig entstehenden abweichenden Lumineszenzbilder,

Fig. 4

ein anderes Ausführungsbeispiel der Erfindung im Querschnitt,

Fig. 5

ein weiteres Ausführungsbeispiel der Erfindung im Querschnitt, und

Fig. 6

ein Ausführungsbeispiel mit mehreren Lumineszenzschichten entsprechend der Erfindung im Querschnitt.

Show it:

Fig. 1

schematically a plan view of a bank note according to the invention with a luminescent see-through register,

Fig. 2

a cross section through the banknote of the Fig. 1 along the line S - S and the luminescence register image that occurs on the back when exposed to UV radiation from the front,

Fig. 3a, b, c

the luminescence register image and the deviating luminescence images that arise depending on the excitation and viewing side,

Fig. 4

another embodiment of the invention in cross section,

Fig. 5

a further embodiment of the invention in cross section, and

Fig. 6

an embodiment with several luminescent layers according to the invention in cross section.

The invention will now be explained using the example of securing security documents such as bank notes. Figure 1 shows a schematic plan view of a bank note 10 with a luminescent see-through register 20 according to an embodiment of the invention. The associated Fig. 2 FIG. 11 shows a cross section through the bank note 10 along the line SS of FIG Fig. 1 .

The bank note 10 contains a translucent substrate in the form of a bank note paper 12, which has a front side 14 and a rear side 16. The banknote paper 12 is translucent both in the visible spectral range and in the UV range, that is to say leads to a certain attenuation of the radiation passing through in both spectral ranges.

In a partial area 19, the substrate thickness of the bank note paper 12 is reduced. The substrate 12 has a thickness d1 in the basic state (in particular outside the areas 1 and 2 or here also in the first area 1). In the sub-area 19, the thickness d2 is smaller than the thickness d1. As a result of the reduction in thickness, the opacity of the substrate in sub-area 19 is also reduced. As will be shown in more detail later, the banknote paper can alternatively be given a higher light permeability locally by means of transparency, for example by applying a transparent varnish.

Furthermore, luminescent imprints 22, 24, 26 are arranged both on the front side 14 and on the rear side 16 of the banknote paper 12. The imprint 22, 24 is applied in a first area 1 on the front side 14. The luminescent print 26 is applied in a second area 2 on the back of the substrate. The luminescent prints 22, 24, 26 have the same luminescent color. The prints could also have the same luminescence strength. In the Figure 2 shown is, however, that the luminescent print 26 is present with a greater layer thickness and thus luminescence strength. The imprints 22, 24, 26 and thus the first area 1 and the second area 2 are arranged in register with one another. In particular, the areas do not overlap, but rather adjoin one another. In Figure 2 In addition, the imprint 26 on the rear side is congruent with the sub-area of reduced substrate thickness 19. The sub-area 19 can - notwithstanding the illustration in FIG Fig. 2 - Be formed on the front side 14 of the substrate.

The luminescent imprints 22, 24, 26 cannot be recognizable in particular when viewed in visible light, so that the luminescent see-through register 20 represents a hidden security feature that only appears when exposed to UV radiation.

In Fig. 1 the luminescent imprints are shown only schematically, the imprints arranged on the front being shown in a filled representation, the imprints arranged on the back being shown unfilled with a dashed border. With normal daylight or artificial light lighting, the luminescent see-through register 20 is the Fig. 1 not visible.

Will now - as in Figure 2 shown - the banknote 10 in the area 1, 2 of the luminescent imprints 22, 24, 26 acted upon from the front side 14 of the banknote with UV excitation radiation 8, the luminescent imprints 22,24,26 generate a luminescent register image 30 for the viewer the back 16 of the banknote (in transparency). The luminescent register image 30 contains an image portion 32 of the luminescent imprint 22 and an image portion 36 of the luminescent imprint 26 adjoining it laterally. The imprints 22, 26 form a luminescent see-through register. The luminescence register image 30 also contains the image portion 34 of the luminescent print 24, which laterally adjoins the other side of the image portion 36.

The arrows of the same length for the image components 32, 36, and 34 in Figure 2 indicate the same brightness values for the image components. In the region 2, the excitation radiation 8 is weakened by the substrate with a reduced thickness d2. As a result of the increased layer thickness of the luminescent print 26, the overall image portion 36 is created with a medium luminescence intensity (brightness). As an alternative or in addition to the increased layer thickness shown, a higher concentration of the fluorescent substance in the paint can also be used here and below to increase the luminescence strength. In the area 1, the excitation radiation 8 excites the luminescence unaffected by the prints 22, 24. However, the luminescence radiation is weakened by the substrate 12 with the thickness d1, so that the image portions 32, 34 likewise arise with a medium luminescence intensity for the viewer of the rear side 16.

The two parameters substrate thickness reduction (by the value d1-d2) and increased layer thickness of the imprint 26 (and / or fluorescent substance concentration in the imprint) are chosen together so that the same brightness value is achieved for the image portions 32, 36 and 36, 34. The parameters must be selected specifically for the excitation opacity and the luminescence opacity of the substrate 12. Optionally, a substrate thickness reduction or an increased luminescence strength alone is sufficient. The combination of both parameters, however, avoids layer thicknesses that are too thick (drying problem, special printing technology required ...) or excessive substrate reduction (instability, cracking ...), respectively.

As in Figure 3a shown, the image portions 32,36,34 of the luminescence register image 30 are indistinguishable for the viewer in this variant or at least the boundary (s) 33 (35) between the image portions 32,36 (and 36,34 ) not visible. The image components 32, 36 and 34 in particular have the same brightness value and the same hue.

Figure 3b shows the front-side luminescence image produced for the observer of the front side 14 when excited from the front side 14, that is to say in plan view. The imprints 22, 24 of the first area 1 on the front side 14 are excited independently of the substrate and luminesce for the observer on the front side, regardless of the substrate. The image components 32, 34 are very clearly visible to the viewer (high brightness value). In the second area 2, the substrate of reduced thickness first acts on the excitation radiation 8 and then on the luminescence radiation of the imprint 26. The central image portion 36, which is twice weakened in this respect, is only visible to the viewer with low brightness (or not visible).

Figure 3c shows the rear side luminescence image that is produced for the viewer of the rear side 16 when excited from the rear side 16, that is to say in plan view. The imprint 26 is excited independently of the substrate and its luminescence as an image portion 36 is likewise independent of the substrate, that is to say at a maximum. For the imprints 22, 24, the excitation radiation is weakened with the substrate thickness d1. In addition, the luminescence radiation is weakened again by the substrate 12 which is not reduced in thickness. As a result, the image portion 32, 24 is no longer recognizable to the viewer of the rear side in plan view in the first area (too low brightness).

Based on Figure 3c the presently more important, so-called luminescence comparison image can also be described. For the observer of the front When viewed through transparency (excitation from the rear), a luminescence comparison image is created which is a different image than the luminescence register image which the viewer can recognize. By comparing the two luminescence images, the viewer can check whether there is a difference and thus verify that the luminescence register image actually contains image components from both sides of the substrate. The print 26 on the back is excited directly, luminescent due to the increased layer thickness with high intensity. The luminescence is only weakened by the substrate of reduced thickness, so it appears to the observer on the front side as an image portion 36 with high brightness. The rear-side excitation radiation is greatly weakened by the substrate, unchanged in thickness, and can essentially not generate any luminescence radiation as image components 32, 24 that can be seen by the viewer.

In the present case, the parameters are not only selected in such a way that a luminescence register image is created for the substrate 12 with a given opacity. In addition, the parameters should be selected in such a way that the luminescence comparison image can be sufficiently distinguished from the luminescence register image for the viewer. Whether the luminescence register image is more like the representation in Figure 3a or that of the representation in Figure 3b is subordinate. The parameters can, for example, be selected accordingly so that the luminescence comparison image or the representation in FIG Figure 3b (as a contrast to Figure 3a) or Figure 3c (as a contrast to Figure 3b ) corresponds.

Actually it would be assumed that the opacity in the substrate is independent of location. However, a discrepancy was recognized for paper substrates made on a paper screen. The UV excitation opacity in the paper substrate is greatly increased on the sieve side. So it decreases significantly towards the opposite side. Therefore, the thickness of the substrate 12 is preferred reduced by removing substrate material from the substrate side. Even a slight reduction in the thickness of the screen side leads to a significant reduction in the UV excitation opacity. The substrate side can be used as a front or back.

For paper substrates, excitation in the near UV range, that is between 365 and 395 nm, preferably between 376 and 389 nm, can be advantageous, since the opacity of the paper substrates is lower in this range.

A paper substrate can in particular also contain titanium dioxide, preferably with a concentration of less than 5% or less than 3%, in particular with a concentration between 1% and 2.5%. It is particularly advantageous to use the anatase modification of titanium dioxide, since it does not absorb long-wave UV light as strongly as the rutile modification of titanium dioxide.

Figure 4 shows an embodiment in which the opacity of the substrate 12 is reduced in areas by transparency.

Analogous to Figure 2 the substrate 12 has luminescent imprints 42,46,44 on the front and back, which are applied in register with one another. The substrate 12 is provided with a transparency 18 for luminescence radiation under the imprint 42. In order to show this alternative, the transparency 18 for luminescence radiation is applied from the rear side 16 in the area of the imprint 44. There is also a transparency 17 for excitation radiation. As shown, each of the transparencies can be present in a certain partial thickness of the substrate or over the entire thickness of the substrate.

The excitation transparency 17 of the substrate 12 reduces the opacity of the substrate 12 in this area. Figure 4 again shows the resulting luminescence register image 50 for viewing in transparency from the rear. The excitation radiation 8 is less attenuated on the way through the substrate 12 in the area of the transparency 17. The luminescent material 46 is excited and luminesced with a correspondingly still high excitation intensity. The luminescence can be recognized by the viewer as an image portion 56 with medium brightness. The prints 42, 44 applied with an increased layer thickness are stimulated immediately and luminesce accordingly intensively. The luminescence is attenuated in the substrate 12 - including the transparent subareas 18 -. To the viewer, the image portions 52, 54 appear with the same brightness as the image portion 56.

In Figure 4 the parameters transparency 17, transparency 18 and luminescence strength of the imprints 42, 44 (in the first area) and 46 (in the second area) are adapted to the opacity of the substrate in such a way that the luminescence register image 50 is created. The luminescence register image 50 can in particular be generated with different color tones of the image components 52, 54, 56 and the same brightness.

Again it can be seen that for an adaptation to the substrate it can be sufficient to choose only one of the parameters. The combination of two or more parameters, however, avoids individual parameter values that are too high.

As on the imprint 46 with the opposed transparency 17 and the imprint 44 and the opposed transparency 18 can be seen, it can be advantageous to provide the printing and the transparency in each of the areas on opposite sides. On the other hand, it will rarely be helpful to provide the transparency as a background for the print. The transparency can also be applied in register or non-register to one another on both sides.

In Figure 4 the transparency 18, which is arranged above the imprint 44, extends from the boundary line (not shown) between the first area 1 and the second area 2 to beyond the first area 1. With its protruding section, the transparency 18 has no effect on the see-through register. It is therefore sufficient if a partial area of reduced opacity 17, 18, 19 is arranged on one side, namely at the area boundary, with the corresponding imprint in the register.

The luminescence intensity of the prints can be indicated by a conversion factor K, which indicates the ratio of the luminescence intensity to the intensity of the excitation radiation: $${\mathrm{I.}}_{\mathrm{vis}}=\mathrm{K}*{\mathrm{I.}}_{\mathrm{UV}}.$$

In the embodiment of Figures 2 and 4th the luminescent prints 22, 24, 26 have partially different luminescence strengths, that is to say different values for the conversion factor K.

und $${\mathrm{I}}_{\mathrm{vis},\mathrm{out}}={\mathrm{T}}_{\mathrm{vis}}*{\mathrm{I}}_{\mathrm{vis},\mathrm{in}}$$

mit 0 < T_UV, T_vis < 1; insbesondere 0,1 <= Tuv, T_vis <=0,9.The relative proportion of light passing through the substrate 12, radiation may be indicated by transmittance Tuv or T _vis. The following relationships apply between the incident intensity I _in and the intensity I _{out emerging from the substrate:} $${\mathrm{I.}}_{\mathrm{UV},\mathrm{out}}={\mathrm{T}}_{\mathrm{UV}}*{\mathrm{I.}}_{\mathrm{UV},\mathrm{in}}$$

and $${\mathrm{I.}}_{\mathrm{vis},\mathrm{out}}={\mathrm{T}}_{\mathrm{vis}}*{\mathrm{I.}}_{\mathrm{vis},\mathrm{in}}$$

with 0 <T _UV , T _vis <1; in particular 0.1 <= Tuv, T _vis <= 0.9.

The translucent banknote paper is therefore neither transparent (Tuv, T _vis = 1) nor opaque (T _UV , T _vis = 0). In Fig. 2 a substrate with high excitation opacity (small Tuv, eg: 0.15) and lower luminescence opacity (greater T _vis , eg: 0.4) is assumed. Fig. 4 shows, however, an example with low excitation opacity and high luminescence opacity. In the exceptional case, not shown in the figures, of a substrate with the same opacity values, the parameters are to be selected in areas such that the luminescence register image differs from the luminescence comparison image in a recognizable manner for the viewer.

der UV-Anregungsstrahlung den lumineszierenden Aufdruck 26 der Rückseite. In diesen Bereichen wird somit eine sichtbare Lumineszenzstrahlung als Bildanteil 36 mit einer Intensität $${\mathrm{I}}_{\mathrm{vis},36}=\mathrm{K}*{\mathrm{I}}_{\mathrm{UV}}=\mathrm{K}*{\mathrm{T}}_{\mathrm{UV},2}*{\mathrm{I}}_{\mathrm{UV}0}$$

erzeugt.In the following, the intensities in the two areas 1, 2 are considered under the simplified assumption of the same luminescence strength. I _{UV, in} let the intensity of the UV excitation radiation 8 from that of the front side. In the partial area of reduced opacity 17, 19, the UV radiation must penetrate the bank note paper 12 in order to be able to excite the imprint 26. A portion of the incident radiation reaches $${\mathrm{I.}}_{\mathrm{UV},2}={\mathrm{T}}_{\mathrm{UV},2}*{\mathrm{I.}}_{\mathrm{UV},\mathrm{in}}$$

of the UV excitation radiation, the luminescent print 26 on the back. In these areas there is thus a visible luminescence radiation as an image component 36 with an intensity $${\mathrm{I.}}_{\mathrm{vis},36}=\mathrm{K}*{\mathrm{I.}}_{\mathrm{UV}}=\mathrm{K}*{\mathrm{T}}_{\mathrm{UV},2}*{\mathrm{I.}}_{\mathrm{UV}0}$$

generated.

wobei von dieser Strahlung nach Durchtritt durch das Substrat 12 noch ein auf den Faktor T_vis,1 reduzierter Anteil auf der Rückseite ankommt. Die Intensität der Lumineszenzstrahlung 32, 34 beträgt auf der Vorderseite somit $${\mathrm{I}}_{\mathrm{vis},32/34}={\mathrm{T}}_{\mathrm{vis},1}*{\mathrm{I}}_{\mathrm{vis},22}={\mathrm{T}}_{\mathrm{vis},1}*\mathrm{K}*{\mathrm{I}}_{\mathrm{UV},0}$$

In the first area, the front-side imprints 22, 24 are excited with the non-weakened UV radiation 8, the visible luminescence radiation generated but is weakened by the substrate material 12. The intensity of the generated luminescence radiation is still on the front $${\mathrm{I.}}_{\mathrm{vis},\mathrm{22nd}}=\mathrm{K}*{\mathrm{I.}}_{\mathrm{UV},\mathrm{in}}$$

of this radiation, after passing through the substrate 12, a _{portion reduced to the factor T vis, 1} arrives on the rear side. The intensity of the luminescence radiation 32, 34 is thus on the front side $${\mathrm{I.}}_{\mathrm{vis},32/34}={\mathrm{T}}_{\mathrm{vis},1}*{\mathrm{I.}}_{\mathrm{vis},\mathrm{22nd}}={\mathrm{T}}_{\mathrm{vis},1}*\mathrm{K}*{\mathrm{I.}}_{\mathrm{UV},0}$$

So if I ₃₂ = I ₃₆ , the sub-area of reduced opacity must be selected so that the following applies $${\mathrm{T}}_{\mathrm{UV},2}={\mathrm{T}}_{\mathrm{vis},1}.$$

For greater layer thicknesses in which non-linear effects occur, a standard value or standard value range for the excitation intensity (conventional UV test lamps) should be used.

The luminescent imprints 22, 24, 26 thus form a luminescent see-through register. It is possible that the complete image information is only visible when the bank note 10 is from one side of the substrate 12 (front side 14 in Fig. 2 ) is exposed to UV radiation 8, and the luminescent image 30 on the opposite side of the substrate (rear side 16 in Fig. 2 ) is looked at.

Another special feature of the see-through register 20 is the side-dependency of the brightness distribution of the displayed luminescence image. As with reference to Figure 3c already described, the luminescence comparison image is produced when the bank note 10 is turned over and viewed again in transparency.

$${\mathrm{I}}_{\mathrm{vis},\mathrm{R},2}=\mathrm{K}*{\mathrm{T}}_{\mathrm{vis},2}*{\mathrm{I}}_{\mathrm{UV}0}$$

The following applies to the intensities of the luminescence radiation in transparency when excited on the rear side: $${\mathrm{I.}}_{\mathrm{vis},\mathrm{R.},1}=\mathrm{K}*{\mathrm{T}}_{\mathrm{UV},1}*{\mathrm{I.}}_{\mathrm{UV}0}$$

$${\mathrm{I.}}_{\mathrm{vis},\mathrm{R.},2}=\mathrm{K}*{\mathrm{T}}_{\mathrm{vis},2}*{\mathrm{I.}}_{\mathrm{UV}0}$$

Since T _{UV, 1 is} significantly greater than T _{vis, 2} , I _{vis, R, 1 is also} significantly greater than I _{vis, R, 2} and the brightness values of the image components are therefore clearly different. This side dependency of the appearance of the generated luminescence images can be used as a further authenticity feature or for verification of the security feature 20.

$${\mathrm{I}}_{\mathrm{vis},\mathrm{V},2}={\mathrm{I}}_{36}={\mathrm{K}}_{26}*{\mathrm{T}}_{\mathrm{UV},2}*{\mathrm{I}}_{\mathrm{UV}0}$$

While it has just been assumed, for the sake of simplicity, that the conversion factor K of the luminescent imprints on the front and back is the same, the conversion factor can of course also be selected to be of different sizes, so that additional possibilities for variation arise. If, in general, K denotes the conversion factor of the luminescent imprints 22, 26 arranged on the front side and K _{R denotes} the conversion factor of the luminescent imprints 24 arranged on the rear side, then when the arrangement is exposed to UV radiation from the rear side, the intensities result on the front side: $${\mathrm{I.}}_{\mathrm{vis},\mathrm{V},1}={\mathrm{I.}}_{32}={\mathrm{K}}_{\mathrm{22nd}}*{\mathrm{T}}_{\mathrm{vis},1}*{\mathrm{T}}_{\mathrm{UV}0}$$

$${\mathrm{I.}}_{\mathrm{vis},\mathrm{V},2}={\mathrm{I.}}_{36}={\mathrm{K}}_{\mathrm{26th}}*{\mathrm{T}}_{\mathrm{UV},2}*{\mathrm{I.}}_{\mathrm{UV}0}$$

gilt. Beispielsweise kann die Lumineszenzstärke der rückseitigen Aufdrucke 24 doppelt so groß gewählt sein wie die der vorderseitigen Aufdrucke (also K₂₆ = 2*K₂₂) und zugleich T_{UV, 2} halb so groß gewählt sein wie T_{vis, 1}. Auch in diesem Fall ist das Erscheinungsbild der erzeugten Lumineszenzbilder in Durchsicht vorzugsweise seitenabhängig. Durch eine Abstimmung der Konversionsfaktoren und der reduzierten Opazitäten könnte allerdings auch ein seitenunabhängiges Erscheinungsbild erzeugt werden.The same brightness values in areas 1, 2 can therefore always be achieved if essentially $${\mathrm{K}}_{\mathrm{22nd}}*{\mathrm{T}}_{\mathrm{vis},1}={\mathrm{K}}_{\mathrm{26th}}*{\mathrm{T}}_{\mathrm{UV},2}$$

applies. For example, the luminescence strength of the back prints 24 can be selected to be twice as large as that of the front prints (i.e. K ₂₆ = 2 * K ₂₂ ) and at the same time T _{UV, 2 can be selected to be} half as large as T _{vis, 1} . In this case too, the appearance of the generated luminescence images when viewed through is preferably side-dependent. By coordinating the conversion factors and the reduced opacities, however, a page-independent appearance could also be created.

Figure 5 shows as a further embodiment of the invention a data carrier 20 with a translucent substrate 12, in which luminescent imprints 62, 64 are applied in a first area on the front side 14 of the substrate and in a second area on the back 16 of the substrate a luminescent imprint 66 in a partial area 19 of reduced substrate thickness lies. In the example, a substrate 12 with high excitation opacity is assumed, so that the three available parameters are used for adaptation in the second area. In addition to the substrate thickness reduction, an excitation transparency 17 and an increased luminescence strength of the imprint 66, for example through an increased luminescence substance concentration, are provided.

The luminescence register image 70 comprises image portions 71, 72, 74, 75 of the front-side imprint 62, 64 in the first area 1 and the image portion 76 of the rear-side imprint 66 in the second area. Since the imprint 62, 64 of the first area 1 extends beyond the partial area 19 of the substrate thickness reduction, the image portions 71, 75 have a lower brightness for the viewer than the image portions 72, 74. Because of the excitation opacity, the luminescent imprints 67, 68 applied in a third area on the rear side of the substrate do not contribute to the luminescence register image 70 or do not luminesce when excited from the front.

The difference in the brightness of the laterally adjoining image components 72, 76 and 76, 74 can be selected in the luminescence register image 70 such that it cannot be seen by the viewer. In addition, if the image portions 72, 76 and 76, 74 have the same color tone, the boundary cannot be seen by the viewer. Not according to the invention, if the image components 72, 76 or 76, 74 differ in color and / or if the brightness value (possibly the same color shade) is different, the boundary is recognizable to the viewer.

The see-through register 20 - already without the further imprints 67, 68 - is designed in such a way that the luminescence register image 70 when stimulated on the front side produces a luminescence comparison image that is distinguishable for the viewer when stimulated on the back side. In the second area 2, the excitation on the back excites the imprint 66 directly to luminescence, which is only slightly weakened by the substrate of reduced thickness. The front-side imprints 62, 64, on the other hand, are only slightly excited in the area of the substrate reduction and not at all outside. If the imprints 62, 64 contain luminescent substances of a first color, here red, and the imprint 66 luminescent substances of a second color, here green, a luminescence register image with differently colored image components (red and green) is created when the front side is excited. In contrast, the uniformly colored (green) luminescence comparison image generated upon excitation from the rear is particularly easy to recognize as different for the viewer. The optional further imprints 67, 68 can further intensify the difference between the luminescence register image and the luminescence comparison image, since, for example, they are only (or primarily) visible to the viewer in transparency in the luminescence comparison image. In particular, the further imprints can have an independent motif in particular have independently (of the second area) selectable outer contour.

The luminescent see-through register 20 can, as just exemplified Figure 5 described but generally applicable, be incorporated into a luminescent overall design on the front and / or a luminescent overall design on the back. Likewise, the luminescence register image can be adapted to the visual design of the front and / or the back or integrated into the visual design, which is formed by non-luminescent, in particular multicolored, imprints and / or other optical security features (not shown). If one of the luminescent imprints were to be replaced by a colored imprint in one of the two areas, one arrives at a simple luminescent image which is in register with a colored imprint.

Luminescence images can also represent true color images by additive color mixing, which are generated, for example, by the luminescence basic dyes luminescence green, luminescence red and luminescence blue. Figure 6 shows an embodiment with a luminescent luminescent register image 90 that is luminescent in true colors.

Luminescent green, luminescent red and luminescent blue, which are printed in corresponding color layers 87, 88, 89, are used as the basic colors. In the first area 1, a luminescent imprint 82, 84, each with three layers of color (or color components), is applied to the front. In the second area 2, only the two colored layers 88, 89, for example luminescent red and luminescent blue, are applied on the front side. The color layer missing on the front side is applied as an imprint 86 on the rear side in register. A true color image portion is located within each of the two areas of the luminescent register image 90. The intensity of the colors thus varies locally, for example according to the resolution available for printing from pixel to pixel. The luminescence register image 90 is formed in the first area 1 by an image component which arises from the true-color (RGB) luminescence of the imprints 82, 84, which is weakened by the substrate 12 with its luminescence opacity. In the second area, the substrate, here reduced in thickness, reduces the intensity of the red and blue luminescence radiation of the imprint 83 in accordance with its visual opacity, and the intensity of the excitation radiation is reduced in accordance with the UV opacity. The green luminescence of the print 86 on the back complements the red-blue luminescence of the front to form a true color image. The reduction in thickness of the substrate in the sub-area 19 and / or the basic luminescence strength of the imprint 86 are selected such that a uniform, true-color luminescence register image 90 results for the viewer. The base luminescence intensity is seen as a luminescence intensity from which the local variation occurs within the area 2. In a simple embodiment, the basic luminescence intensity is the mean value of the luminescence intensity in the imprint 86.

A luminescence register image 90 in real colors is created for the viewer. In preferred refinements, the viewer does not recognize the boundary between the areas (seamless luminescence register image 90). In other configurations, the boundary between the first and the second area is emphasized for the viewer.

As an alternative to the superimposed arrangement of the basic colors shown here, the basic colors can also be arranged next to one another in the grid or only partially one above the other.

In Figure 6 an optional luminescent imprint 85 and a luminescence comparison image 91 are also shown.

When the rear side is excited, the luminescence comparison image 91 is created for the observer on the front side. The luminescence comparison image 91 contains an image portion in the second area 2 that is generated by the (green) print 86 on the back side. The rear imprint 85 is not excited from the front. It can, for example, contain luminescent white as a luminescent dye and / or comprise a partial image held in gray levels. For the viewer, the back imprint 85 generates an image portion of the luminescence comparison image 91 when the back is excited in the third area 3. The luminescence comparison image 91 thus comprises a colored (green) and a non-colored (white) partial image. The partial image of the second area is thus contained both in the luminescence comparison image 91 (monochrome) and in the luminescence register image 90 (colored). The side dependency can thus be verified particularly easily for the viewer.

List of reference symbols

1, 2, 3

Areas

8th

UV excitation radiation

10

Banknote

12th

Banknote paper

14th

front

16

back

17th

Partial areas of reduced excitation opacity

18th

Partial areas of reduced luminescence opacity

19th

Sub-areas of reduced substrate thickness

20th

See-through register

22, 24

luminescent prints on the front

26th

luminescent prints on the back

30th

Luminescence register image

32, 34, 36

Luminescence image components

33, 35

Boundary line

42, 44

luminescent prints on the front

46

luminescent prints on the back

50

Luminescence register image

62, 64

luminescent prints on the front

66

luminescent prints on the back

70

Luminescence register image

71, 72, 74, 75.76

Luminescence image components

82.83.84

luminescent prints on the front

85.86

luminescent prints on the back

87.88.89

R / G / B layers

90

Luminescence register image

91

Luminescence comparison image

Claims (15)

1. Data carrier, in particular value documents or security document, with a translucent substrate (12) with a front side and a back side;
   wherein in a first region (1) luminescent material (22) is applied to the front side of the substrate (12);
   wherein in a second region (2) luminescent material (26) is applied to the back side of the substrate (12);
   wherein the first region (1) and the second region (2) are arranged in register with one another; and
   wherein for the viewer, upon excitation (8) from the front side, a luminescence image (30) is produced in transmission, which comprises an image portion (32) of the first region (1) and comprises an image portion (36) of the luminescent second region (2) that laterally adjoins the image portion (32) of the first region (1); characterized in that
   in the first region (1) and the second region (2) at least one parameter, an opacity of the translucent substrate (12) and/or a luminescence strength of the luminescent material, is chosen differently depending on the region, and
   the mutually adjoining image portions (32, 36) of the luminescence image (30) have the same brightness value.
2. The data carrier according to claim 1, characterized in that the luminescence image (30) is produced for the viewer when the front side is excited (8) in transmission, and when the back side is excited in transmission, a recognizably different back-side luminescence image is produced.
3. The data carrier according to claim 2, characterized in that in the back-side luminescence image either only one image portion of one of the two luminescent regions (1, 2) is contained or a difference of the brightness values of the image portions of the two luminescent regions (1, 2) is recognizably increased.
4. The data carrier according to any of the preceding claims, characterized in that the translucent substrate (12) comprises a partial region (19) of reduced substrate thickness and/or at least one transparentized partial region (17, 18).
5. The data carrier according to claim 4, characterized in that the partial region (19) of reduced substrate thickness is formed by physical removal of substrate material after the substrate has been manufactured.
6. The data carrier according to claim 5, characterized in that the translucent substrate is a fiber-based substrate which is manufactured by means of a screen, wherein the substrate material is physically removed on the screen side of the substrate.
7. The data carrier according to claim 4, characterized in that the translucent substrate is a fiber-based substrate and the partial region of reduced substrate thickness is formed by a watermark produced during fiber-based manufacture of the substrate, wherein the partial region of reduced substrate thickness preferably is additionally transparentized.
8. The data carrier according to any of claims 4 to 7, characterized in that the transparentized partial region (18) is luminescence-transparentized and/or the transparentized partial region (17) is excitation-transparentized.
9. The data carrier according to any of the preceding claims, characterized in that the luminescent region (1) of the front side and/or the luminescent region (2) of the back side extend beyond the partial region of reduced opacity.
10. The data carrier according to any of the preceding claims, characterized in that the luminescent material (22, 24) is applied with different layer thicknesses and/or luminescent substance concentrations.
11. The data carrier according to at least one of claims 1 to 10, characterized in that the transition between the two image portions (22, 26) in the luminescence image (30) cannot be recognized by the viewer
    and/or the composite motif of the luminescence register image (30) is produced for the viewer only in the case of front-side excitation in transmission.
12. The data carrier according to at least one of claims 1 to 11, characterized in that the translucent substrate is a fiber-based substrate, in particular a paper substrate or the paper ply of a composite substrate.
13. A method for manufacturing a data carrier, in which

    - a translucent substrate is supplied;

    - luminescent material is applied to the front side of the substrate in a first region and to the back side of the substrate in a second region which is arranged in a manner registered with the first region;
    wherein a partial region of reduced opacity of the translucent substrate (12) is produced in the first region (1) and/or the second region (2) and/or a luminescence intensity of the luminescent material is chosen to be region-dependently different in the two regions, wherein the two regions form a luminescent transmission register which, when excited (8) from the front side, produces for the viewer a luminescence image (30) in transmission, which has an image portion (32) of the first region (1) and an image portion (36) of the luminescent second region (2) that laterally adjoins the image portion (32) of the first region (1), and
    wherein the mutually adjoining image portions (32, 36) of the luminescence image (30) have the same brightness value.
14. The method according to claim 13, characterized in that a paper substrate or a composite substrate with a paper ply is supplied as the translucent substrate and that during the papermaking of the paper substrate or of the paper ply a watermark is produced which forms a partial region of reduced opacity.
15. The method according to claim 13, characterized in that
    a partial region of reduced opacity is produced by physical removal of substrate material after the substrate has been manufactured, in particular by laser ablation or with the aid of a mechanical milling machine, or
    a partial region of reduced opacity is produced by applying a transparentizing agent.

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