EP3339049A1 - Data carrier with luminescent regions - Google Patents

Abstract

The invention relates to a data carrier (10), in particular value or security document, having a translucent substrate (12) with a front side (14) and a rear side (16) and with both on the front side (14) in a first area and on the rear side (16) arranged in a second region luminescent material. When viewed from the front (8), a luminescence image (30), which comprises an image portion (32) of the first area (1) and a laterally adjacent image portion (36) of the luminescent second area (2), is produced for the viewer. 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 intensity of the luminescent material are selected differently depending on the region.

Description

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

Data carriers, such as valuables or identity documents, but also other valuables, such as branded goods, are often provided with security elements for the purpose of security, which permit verification of the authenticity of the data carrier and at the same time serve as protection against unauthorized reproduction.

In this context, it has long been known to use luminescent substances for securing value or identity documents. The presence of the luminescent substances can then be tested, for example, with the aid of a UV lamp. For example, in a security paper fluorescent mottled fibers can be incorporated, which usually consist of short, provided with a fluorescent coating fibers. In normal lighting, the mica fibers are invisible, but under UV illumination, they appear clearly in their bright fluorescence, for example in red, green or blue, despite their small size. Especially in the pass range, the printing of true color luminescence images is known. The implementation is usually done in ink-jet printing with special colors, which are not visible in normal lighting and after excitation by UV light a comparable color impression as a classic picture, such as a portrait of the passport owner show.

Also known are security features that are not or not fully visible in supervision, but only be seen in review, such as shown in WO 2012/113546 A2 ,

Ink-jet fluorescent inks, in particular, have become more readily available, in particular through online retailing, enabling a counterfeiter to make counterfeits. Also, ink manufacturers offer fluorescent colors that are designed for technical gadgets or brand protection.

WO-2013/091860-A1 describes a chemical approach to detect counterfeits with fake fluorescence colors. In WO 2014/082754 A1 normal and luminescent inks are arranged side by side so that, depending on the conditions of excitation, a noticeable additional effect arises for the viewer.

Based on this, the present invention seeks to provide a data carrier of the type mentioned above with an attractive appearance and high security against counterfeiting.

This object is solved by the features of the independent claim. Further 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 to one another. Both the excitation and the luminescence must be at least partially due to the Substrate through which usually has a very different opacity for excitation and luminescence. In addition to the already difficult to achieve registerability for a counterfeiter, the vote - especially for a page-dependent different luminescence - not easily adjustable.

A volume, such as value or security document, comprises a translucent substrate having a front and a back. In a first region, luminescent material is applied on the front side of the substrate, and in a second region, which is arranged in register with the first region, luminescent material is applied on the backside of the substrate. When viewed from the front, a viewer is provided with a luminescence register image, which comprises an image component of the first region and an image component of the second region laterally adjacent to this image component. In the first region and the second region, at least one parameter, an opacity of the translucent substrate and / or a luminescence intensity of the luminescent material are selected differently depending on the region.

In the context of this description, luminescence is understood in particular to mean 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 major surfaces of a data carrier. In principle, each of the main surfaces, in particular independently of further properties of the data carrier, can be selected as the front side.

For the sake of completeness, it is pointed out that viewing is in review when excitation and viewing take place from different sides, ie in particular an excitation from the front for the viewer of the back or an excitation from the back for the observer of the front. On the other hand, an observation in supervision is given if the suggestion and consideration are from the same side.

The first and second regions of luminescent material form a luminescent see-through register. The present luminescent see-through register generates page-dependent different luminescence for the viewer in review.

The at least one parameter is chosen such that the luminescence register image can be recognized by the viewer as an image that is complementary to the image portions. In particular, the range-dependent parameter is selected such that a difference in the brightness values of the adjacent image components of the luminescence register image is reduced (as compared to a difference of the brightness values without adaptation). Particularly preferably, the adjacent image components of the luminescence register image have the same brightness value.

For the viewer, the luminescence register image is generated in the case of front-side excitation, and a clearly different luminescence comparison image is generated when viewed back on excitation.

For a better discrimination of the luminescence images, the image generated in the case of front excitation can be referred to as a luminescence register image. The image produced in the case of back excitation can be referred to as the luminescence comparison image. Corresponding For example, an image formed on the front and back of the viewer can be referred to as a luminescence front-side image and a back-side luminescence image, respectively.

In particular, the comparative luminescent image can serve the observer to verify the page dependency of the luminescent see-through register. The at least one parameter is preferably selected such that the recognizable, different, luminescence comparison image serving to verify the side dependency of the luminescent transparent register is produced.

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

Alternatively, or additionally, the luminescent frontside image may serve the viewer to verify the page dependency of the luminescent see-through register. The at least one parameter is preferably selected such that the visibly different, luminescent front image serving for verifying the side dependency of the luminescent transparent register is produced. The luminescence front image then preferably contains only an image portion of one of the two luminescent regions. Alternatively, a difference in the brightness values of the image components of the two luminescent regions can be visibly increased for the viewer in the luminescence front image.

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

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

If the translucent substrate is a paper substrate or if the translucent substrate comprises a paper layer, then the subregion of reduced substrate thickness is advantageously formed by a watermark produced in paper production of the paper substrate or the paper layer.

In another, likewise advantageous refinement, the subregion of reduced substrate thickness is produced by a 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 screen side of a substrate produced by means of a (drainage) screen. The substrate rests on the screen during manufacture with the screen side. The excitation opacity of the substrate is increased on the screen side, ie it sinks (non-linearly) within the substrate from the screen side to the opposite side. Substrate removal from the sieve side thus has a disproportionate effect on reducing excitation opacity.

The subregion of reduced opacity may also be a transparent subregion of the substrate. In this case, the layer thickness in the opacity-reduced portion is unchanged, but the transmission of the substrate material for visible light and / or UV radiation is locally increased. A transparent subregion can be transparent (luminescence-transparent) in the visible spectral range and / or in the spectral region of the excitation, that is to say in particular in the IR or near UV region or UV range, be transparent (stimulated-transparent). Such an increase in the transmission can be generated for example by the application of a transparentizing paint. The transparentizing agent may preferably be produced based on a paint or a lacquer. Alternatively, a transparentization by means of high-energy excitation radiation is conceivable.

With particular advantage, the subregion of reduced opacity is likewise arranged in register with the (first or second) luminescent region. Register-accurate generation of the front and rear luminescent regions and the subregions is only possible with high-quality printing machines or complicated manual assembly of ink-jet printing and therefore makes it much more difficult to readjust.

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

For the viewer, the transition (the boundary or the boundary line) between the two image portions in the luminescence register image in a preferred embodiment is not recognizable. The contiguous image components of the luminescence register image have the same brightness value and the same hue for the viewer.

Advantageously, a non-luminescent region adjoins a borderline between the two luminescent regions on one or both sides. The register-compliant addition of the image components to the luminescence register image is thus even better recognizable.

The boundary line between the two image portions (or areas) may preferably be non-linear. An adjustment of the register accurate arrangement is further complicated.

For the viewer, the (linear or non-linear) transition (the boundary) between the two image portions in the luminescent register image may be recognizable in another embodiment. The adjoining image components of the luminescence register image then preferably have the same brightness value and different color tones or the same color tone and different brightness values for the viewer.

The luminescence intensity of the deposited luminescent material can be adjusted by the layer thickness of the luminescent material and / or luminescence concentration in the luminescent material. Should the luminescent material be applied in a screened manner, it is alternatively also possible to set by the screening, in particular the dot size. The luminescence intensity of the luminescent regions of the front and back can be the same, but it is also possible that the luminescent regions of the front and back have different luminescence intensity.

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

In further advantageous embodiments, the luminescent regions of the front side and / or the luminescent regions of the back side extend beyond the partial region of reduced opacity. In this way, the front side and the rear side can, for example, each show different luminescence images which contain an identical image part in the subregion of reduced opacity. However, the luminescent regions of the front side and the luminescent regions of the back side are also advantageously matched to one another in the sub-region of reduced opacity in this case as well.

In an advantageous embodiment, the luminescent regions of the rear side and the front side contribute image components of different color to the luminescence image.

The translucent substrate has a predetermined thickness in its ground state / non-thickness-changed region / a third region. The opacity of the substrate is (among other things) dependent 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 considered translucent, the corresponding opacity value (O = 1 / T) is in the range of 1.11 to 10. The translucent substrate preferably has a luminescence Opacity between 1.5 and 9, preferably between 2.1 and 5 on. 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 on one or both sides with a transparent plastic film. However, to avoid misunderstanding, it is noted that a transparent substrate, even if it should be provided with non-transparent imprints and / or coatings, is by no means a translucent substrate in the present sense.

Advantageously, the luminescent areas are not visible when viewed in visible light, so that the luminescent see-through register is a hidden security feature that occurs only when exposed to UV radiation in appearance.

In a method for producing a data carrier, in particular according to at least one of the aspects described so far, a translucent substrate is provided and arranged on the front side of the substrate in a first region and on the back side of the substrate in a second region registered to the first region is provided with luminescent material. In the first region (and / or the second region), a partial region of reduced opacity of the translucent substrate is generated and / or a luminescence intensity of the luminescent material is selected differently depending on the region in the two regions. The two areas form a luminescent read-through register, which generates a luminescence register image for the viewer when excited from the front, which comprises an image portion of the first area and an image portion of the luminescent second area laterally adjacent to the image portion of the first area.

In an advantageous embodiment, a paper substrate or a composite substrate with a paper layer is provided as the translucent substrate, and in the papermaking of the paper substrate or paper layer, a watermark is formed which forms the portion of reduced opacity.

In another, likewise advantageous refinement, the subregion of reduced opacity is produced by a 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 subregion of reduced opacity can also be produced by applying a translucent agent, for example a transparentizing lacquer.

Furthermore, it is basically also possible to produce partial areas of different opacity by the use of UV blockers. For example, in each case UV blockers can be arranged below the luminescent regions on the front and back side of the data carrier in a subarea, so that a complete luminescence image only results in a view beyond those UV-blocked regions. The UV blockers of the front and back can also be arranged laterally offset from one another according to a further embodiment. As a result, it can be achieved, for example, that the luminescence information in an overlapping region of the opposing UV blockers is identical on examination from both sides and differs outside the overlapping region. 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 and advantages of the invention are 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.

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

1 is a schematic plan view of a banknote according to the invention with a luminescent transparent register;

Fig. 2

a cross section through the banknote of Fig. 1 along the line S - S and the luminescence register image resulting from UV exposure from the front side on the rear side,

Fig. 3a, b, c

the luminescence register image and the corresponding excitation and viewing page-dependent deviating luminescence images,

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 banknotes. FIG. 1 schematically shows a plan view of a banknote 10 with a luminescent see-through register 20 according to an embodiment of the invention. The associated Fig. 2 shows a cross section through the banknote 10 along the line SS of Fig. 1 ,

The banknote 10 contains a translucent substrate in the form of a banknote paper 12, which has a front side 14 and a backside 16. The banknote paper 12 is translucent both in the visible spectral range and in the UV range, thus leading in both spectral ranges to a specific weakening of the radiation passing through.

In a partial area 19, the substrate thickness of the banknote paper 12 is reduced. The substrate 12 has a thickness d1 in the ground state (in particular outside the regions 1 and 2 or here also in the first region 1). In the partial region 19, the thickness d2 is smaller than the thickness d1. The thickness reduction also reduces the opacity of the substrate in the partial region 19. As will be shown in more detail later, the banknote paper may alternatively be given a higher translucency locally by means of transparency, for example by applying a transparentizing lacquer.

Next 12 luminescent imprints 22, 24, 26 are arranged on both the front side 14 and on the back 16 of the banknote paper. The imprint 22, 24 is applied in a first region 1 on the front side 14. The luminescent imprint 26 is applied in a second region 2 on the back side of the substrate. The luminescent imprints 22, 24, 26 have the same luminescent color. The imprints could also have the same luminescence intensity. In the FIG. 2 shown is, however, that the luminescent imprint 26 is present with a higher layer thickness and thus luminescence intensity. The imprints 22, 24, 26 and thus the first area 1 and the second area 2 are arranged in register with each other. In particular, the areas do not overlap but adjoin one another. In FIG. 2 In addition, the imprint 26 of the rear side is congruent with the subregion of reduced substrate thickness 19. The subregion 19 may differ from the illustration in FIG Fig. 2 - Be formed on the front side 14 of the substrate.

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

In Fig. 1 the luminescent imprints are shown only schematically, wherein the arranged on the front prints in filled representation, which are arranged on the back prints unfilled shown with dashed edge. In normal daylight or artificial lighting, the luminescent see-through register 20 is the Fig. 1 not visible.

Will now - as in FIG. 2 the banknote 10 in the region 1, 2 of the luminescent imprints 22, 24, 26 is exposed to UV excitation radiation 8 from the front side 14 of the banknote, the luminescent imprints 22, 24, 26 produce a luminescence register image 30 for the viewer the reverse 16 of the banknote (in review). The luminescence register image 30 contains an image portion 32 of the luminescent imprint 22 and a laterally adjacent image portion 36 of the luminescent imprint 26. The imprints 22, 26 form a luminescent see-through register. The luminescence register image 30 further contains the image portion 34 of the luminescent imprint 24 which laterally adjoins the other side of the image portion 36.

The same long arrows of the image parts 32,36, and 34 in FIG. 2 indicate the same brightness values for the image components. In region 2, the excitation radiation 8 is weakened by the substrate of reduced thickness d2. Due to the increased layer thickness of the luminescent imprint 26, the overall image portion 36 with an average luminescence intensity (brightness) is formed. As an alternative or in addition to the illustrated increased layer thickness, here and in the following, a higher concentration of the fluorescent substance in the ink can be used to increase the luminescence intensity. In the region 1, the excitation radiation 8 excites the luminescence uninfluenced by the imprints 22, 24. However, the luminescence radiation is weakened by the substrate 12 with the thickness d1, so that the image portions 32, 34 also result in medium luminescence intensity for the observer 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 fluorescence concentration in the imprint) are jointly selected such 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 intensity alone is sufficient. However, the combination of both parameters avoids too high layer thicknesses (drying problem, special printing technology needed ...) or excessive substrate reduction (instability, cracking ...) respectively.

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

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

Figure 3c shows the rear side luminescence image resulting for the viewer of the rear side 16 when excited by the rear side 16, that is, in plan view. The imprint 26 is excited independently of the substrate and its luminescence is also independent of the substrate as the image portion 36, that is to say 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 non-thickness-reduced substrate 12. As a result, the image viewer 32, 24 is no longer recognizable to the observer of the rear side in the first area (too low brightness).

Based on Figure 3c It is also possible to describe the presently more important so-called luminescence comparison image. For the viewer of the front When viewed in phantom (excitation from the back side), a luminescence comparison image is created, which is a different image to the viewer than the luminescence register image. The viewer can check by comparing the two luminescent images to see if there is a difference and thus verify that the luminescent register image actually contains image portions from both sides of the substrate. The print 26 on the backside is excited directly, luminesces due to the increased layer thickness with high intensity. The luminescence is weakened only by the substrate of reduced thickness, so it appears to the observer of the front as an image portion 36 with high brightness. The back excitation radiation is greatly weakened by the substrate unchanged thickness and can essentially produce no recognizable for the viewer luminescence radiation as image portions 32, 24.

In the present case, the parameters are not only selected such that a luminescence register image is produced for the substrate 12 with a given opacity. In addition, the parameters should be selected so that the luminescence comparison image for the viewer is sufficiently distinguishable from the luminescence register image. Whether the luminescence register image rather the representation in FIG. 3a or the representation in FIG. 3b is equivalent, is subordinate. The parameters may, for example, be selected accordingly such that the luminescence comparison image or the representation in FIG FIG. 3b (as a contrast to FIG. 3a) or FIG. 3c (as a contrast to FIG. 3b ) corresponds.

In fact, it might be assumed that the opacity in the substrate is location independent. However, a deviation was detected for paper substrates made on a papermaking screen. The UV excitation opacity in the paper substrate is greatly increased on the screen side. It therefore 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 thickness of the screen side leads to a significant reduction in UV excitation opacity. The substrate side can be used as front or back.

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

A paper substrate may 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%. In particular, it is advantageous to use the anatase modification of titanium dioxide, since it does not absorb the long-wave UV light so strongly in comparison with the rutile modification of titanium dioxide.

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

Analogous to FIG. 2 For example, the substrate 12 has front and back luminescent imprints 42, 46, 44 which are applied in registry with each other. The substrate 12 is provided under the imprint 42 with a luminescent radiation transparent 18. In order to show this alternative, in the area of the imprint 44, the transparency 18 for luminescence radiation is applied from the rear side 16. Furthermore, there is a transparency 17 for excitation radiation. As shown, each of the transparentizations can be present in a specific partial thickness of the substrate or can be present over the entire substrate thickness.

The excitation transparency 17 of the substrate 12 reduces the opacity of the substrate 12 in this area. FIG. 4 again shows the resulting luminescent register image 50 for viewing from the rear. The excitation radiation 8 is less attenuated on the way through the substrate 12, in the region of the transparency 17. The luminescent material 46 is excited and luminescent with correspondingly high excitation intensity. The luminescence is recognizable to the viewer as an image portion 56 with medium brightness. The applied with increased film thickness imprints 42, 44 are directly excited and luminesce accordingly intense. The luminescence is attenuated in the substrate 12, including the transparent subregions 18. For the viewer, the image portions 52, 54 appear with the same brightness as the image portion 56.

In FIG. 4 Thus, the parameters transparentization 17, transparentization 18 and luminescence intensity of the imprints 42, 44 (in the first region) and 46 (in the second region) are adapted to the opacity of the substrate such that the luminescence register image 50 is produced. The luminescence register image 50 can be generated in particular with different hues of the image portions 52, 54, 56 and the same brightness.

Again, it will be appreciated that for adaptation to the substrate, it may be sufficient to choose only one of the parameters. However, the combination of two or more parameters may avoid excessive individual parameter values.

As with the imprint 46 with the opposite transparency 17 and the imprint 44 and the opposite transparency 18, it may be advantageous to provide the imprint 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 to both sides of the page, either passaged or unpopulated.

In FIG. 4 extends the transparency 18, which is disposed over the imprint 44, from the boundary line, not shown, between the first region 1 and the second region 2 to beyond the first region 1 addition. With its overhanging portion, the transparency 18 does not affect the see-through register. It is therefore sufficient if a subregion of reduced opacity 17, 18, 19 is arranged on one side, namely at the region boundary, with the corresponding imprint in the register.

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

In the embodiment of Figures 2 and 4 the luminescent imprints 22, 24, 26 partially different luminescence, ie 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 < Tuv, T_vis < 1; insbesondere 0,1 <= Tuv, T_vis <=0,9.The relative proportion of the radiation passing through the substrate 12 can be indicated by the transmittance T _UV or T _vis . Between the incident intensity I _in and the intensity I _out emerging from the substrate, the relationships apply: $${\mathrm{I}}_{\mathrm{UV}.\mathrm{out}}={\mathrm{T}}_{\mathrm{UV}}*{\mathrm{I}}_{\mathrm{UV}.\mathrm{in}}$$

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

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

The translucent banknote paper is thus neither transparent (Tuv, T _vis = 1) nor opaque (Tuv, T _vis = 0). In Fig.2 is assumed to be a substrate with high excitation opacity (small Tuv, for example: 0.15) and lower luminescence opacity (larger T _vis , eg: 0.4). Fig. 4 shows an example with low excitation opacity and high luminescence opacity. In the exceptional case of a substrate having the same opacity values, which is not shown figuratively, the parameters are to be selected in regions such that the luminescence register image differs noticeably from the luminescence comparison image for the observer.

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

erzeugt.In the following, the intensities in the two regions 1, 2 are considered under the simplifying assumption of the same luminescence intensity. I _UV, is 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 banknote paper 12 in order to be able to excite the imprint 26. From the incident radiation reaches a share $${\mathrm{I}}_{\mathrm{UV}.\mathrm{2}}={\mathrm{T}}_{\mathrm{UV}.\mathrm{2}}*{\mathrm{I}}_{\mathrm{UV}.\mathrm{in}}$$

the UV excitation radiation the luminescent imprint 26 of the back. In these areas, therefore, a visible luminescence radiation as an image portion 36 with an intensity $${\mathrm{I}}_{\mathrm{vis}.\mathrm{36}}=\mathrm{K}*{\mathrm{I}}_{\mathrm{UV}}=\mathrm{K}{*}_{\mathrm{UV}.\mathrm{2}}*{\mathrm{I}}_{\mathrm{UV}\mathrm{0}}$$

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 $${\mathrm{I}}_{\mathrm{vis},\mathrm{32}/\mathrm{34}}={\mathrm{T}}_{\mathrm{vis},\mathrm{1}}*{\mathrm{I}}_{\mathrm{vis},\mathrm{22}}={\mathrm{T}}_{\mathrm{vis},\mathrm{1}}*\mathrm{K}*{\mathrm{I}}_{\mathrm{UV},\mathrm{0}}$$

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

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

So if I ₃₂ = I ₃₆ , the sub-range of reduced opacity is to be chosen so that applies $${\mathrm{T}}_{\mathrm{UV}.\mathrm{2}}={\mathrm{T}}_{\mathrm{vis}.\mathrm{1}}\mathrm{,}$$

For larger layer thicknesses where non-linear effects occur, the tuning should be for a standard or default range of excitation intensity (common UV test lamps).

The luminescent imprints 22, 24, 26 thus form a luminescent transparent register. It is possible that the complete image information only becomes visible when the banknote 10 is moved from one side of the substrate 12 (front side 14 in FIG Fig. 2 ) is exposed to UV radiation 8, and the luminescence image 30 on the opposite side of the substrate (back 16 in Fig. 2 ) is looked at.

The further special feature of the transparent register 20 is the lateral dependence of the brightness distribution of the illustrated luminescence image. As with respect to Fig. 3c already described, the Luminesznez comparison image is formed when the banknote 10 is turned over and viewed again in a transparent view.

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

For the intensities of the luminescence radiation viewed through with excitation on the back: $${\mathrm{I}}_{\mathrm{vis}.\mathrm{R}.\mathrm{1}}=\mathrm{K}*{\mathrm{T}}_{\mathrm{UV}.\mathrm{1}}*{\mathrm{I}}_{\mathrm{UV}\mathrm{0}}$$

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

Since T _{UV, 1 is} significantly larger than T _{vis, 2} , I _{vis, R, 1 is also} significantly larger than I _{vis, R, 2,} and the brightness values of the image constituents are therefore markedly different. This page 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.

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

While it has just been assumed for the sake of simplicity that the conversion factor K of the luminescent imprints of the front and rear side is the same, the conversion factor can, of course, also be chosen to be different, so that additional possibilities of variation result. If the conversion factor of the luminescent imprints 22, 26 and K _R arranged on the front side generally denotes the conversion factor of the luminescent imprints 24 arranged on the rear side, the intensities result when the arrangement with UV radiation is applied from the rear side on the front side: $${\mathrm{I}}_{\mathrm{vis}.\mathrm{V}.\mathrm{1}}={\mathrm{I}}_{\mathrm{32}}={\mathrm{<figure-callout\; id="22"\; label="K"\; filenames="imgf0001.png"\; state="\{\{state\}\}">K</figure-callout>}}_{\mathrm{22}}*{\mathrm{T}}_{\mathrm{vis}.\mathrm{1}}*{\mathrm{I}}_{\mathrm{UV}\mathrm{0}}$$

$${\mathrm{I}}_{\mathrm{vis}.\mathrm{V}.\mathrm{2}}={\mathrm{I}}_{\mathrm{36}}={\mathrm{<figure-callout\; id="26"\; label="K"\; filenames="imgf0001.png"\; state="\{\{state\}\}">K</figure-callout>}}_{\mathrm{26}}*{\mathrm{T}}_{\mathrm{UV}.\mathrm{2}}*{\mathrm{I}}_{\mathrm{UV}\mathrm{0}}$$

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.Equal brightness values in the regions 1, 2 can therefore always be achieved, if essentially $${\mathrm{<figure-callout\; id="22"\; label="K"\; filenames="imgf0001.png"\; state="\{\{state\}\}">K</figure-callout>}}_{\mathrm{22}}*{\mathrm{T}}_{\mathrm{vis}.\mathrm{1}}={\mathrm{<figure-callout\; id="26"\; label="K"\; filenames="imgf0001.png"\; state="\{\{state\}\}">K</figure-callout>}}_{\mathrm{26}}*{\mathrm{T}}_{\mathrm{UV}.\mathrm{2}}$$

applies. For example, the luminescence intensity of the rear-side imprints 24 may be twice as large as that of the front-side imprints (ie K ₂₆ = 2 * K ₂₂ ) and at the same time T _{UV, 2 may be} half as large as T _{vis, 1} . Also in this case, the appearance of the generated luminescence images in view is preferably page-dependent. By matching the conversion factors and the reduced opacities, however, a page-independent appearance could also be generated.

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

The luminescence register image 70 comprises image components 71, 72, 74, 75 of the front-side imprint 62, 64 in the first region 1 and the image component 76 of the rear-side imprint 66 in the second region. Since the imprint 62, 64 of the first region 1 extends beyond the subregion 19 of the substrate thickness reduction, the image components 71, 75 have a lower brightness for the viewer than the image components 72, 74. Owing to 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 in front excitation.

The difference in the brightness of the laterally adjoining image components 72, 76 and 76, 74 may be selected in the luminescence register image 70 such that it is not recognizable to the viewer. In addition, the same hue of the image components 72,76 and 76, 74, the limit for the viewer is not visible. With different hue of the image components 72,76 or 76, 74 and / or with different brightness value (possibly same hue), the limit for the viewer is recognizable.

The see-through register 20 is - already without the other imprints 67, 68 - designed so that the luminescence register image 70 when viewed from the front excitation and a discernible for the viewer distinguishable luminescence comparison image with back excitation in view. In the second region 2, the backside excitation directly excites the imprint 66 for luminescence, which is only slightly weakened by the substrate of reduced thickness. The front-side imprints 62, 64, on the other hand, are stimulated only slightly and not at all in the region of substrate reduction. If the imprints 62, 64 contain luminescent substances of a first color, in this case red, and the imprint 66 luminescent substances of a second color, green here, a luminescence register image with differently colored image portions (red and green) is produced on front excitation. On the other hand, the uniformly colored (green) luminescence comparison image produced with back excitation is particularly well recognizable to the observer as differently recognizable. The optional further imprints 67, 68 may further enhance the difference between the luminescent register image and the luminescent comparative image since they are only visible to the viewer (or primarily) in the comparative luminescence image. In particular, the other imprints an independent motif, with in particular independently (from the second area) have selectable outer contour.

The luminescent see-through register 20 may, as just for example FIG. 5 however, generally applicable, may be incorporated into a total luminescent design on the front side and / or a luminescent overall design on the back side. 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 multi-colored, imprints and / or other optical security features not shown. If you replace one of the luminescent imprints in one of the two area by a colored imprint, one arrives at a simple luminescence image, which is in the register with a colored imprint.

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

The basic colors used are luminescence green, luminescent red and luminescent blue, which are printed in corresponding color layers 87, 88, 89. In the first area 1, a luminescent imprint 82, 84 with three color layers (or color portions) is applied on the front side. In the second region 2, only the two color layers 88, 89, for example luminescent red and luminescent blue, are applied on the front side. The front missing color layer is applied as a print 86 back in the register. Within each of the two areas is a true color image portion of the luminescence register image 90. The intensity of the colors thus varies locally, for example according to the pixel-to-pixel resolution available on the print. The luminescence register image 90 is formed in the first region 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 region, the intensity of the red and blue luminescence radiation of the imprint 83 is reduced by the substrate, which is reduced in thickness here, 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 backprint 86 complements the red-blue luminescence of the front to the true color image. The reduction in thickness of the substrate in the partial area 19 and / or the basic luminescence intensity of the imprint 86 are selected so as to give the viewer a uniform, true-color luminescence register image 90. As a base luminescence strength, a luminescence intensity is seen, from which the local variation takes place within the region 2. In a simple embodiment, the basic luminescence intensity is the mean value of the luminescence intensity in the print 86.

A luminescence register image 90 in true colors is created for the viewer. In preferred embodiments, the viewer does not recognize the boundary between the regions (seamless luminescence register image 90). In other embodiments, the boundary between the first and second areas is highlighted to the viewer.

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

In FIG. 6 In addition, an optional luminescent imprint 85 and a luminescence comparison image 91 are shown.

In the case of back excitation, the luminescence comparison image 91 is produced for the viewer of the front side. The luminescence comparison image 91 contains an image portion in the second region 2, which is produced by the back (green) imprint 86. The backprint 85 is not excited from the front. It may, for example, contain luminescent white as luminescent dye and / or comprise a partial image held in gray scale. For the viewer, the rear-side print 85 generates an image portion of the comparative luminescence image 91 in the third region 3 when excited on the back side. The luminescence comparison image 91 thus comprises a colored (green) and a non-colored (white) partial image. The partial image of the second region is thus contained both in the luminescence comparison image 91 (monochrome) and in the luminescence register image 90 (multicolored). For the viewer, the page dependency is thus particularly easy verifiable.

LIST OF REFERENCE NUMBERS

1, 2, 3

areas

8th

UV excitation radiation

10

bill

12

Banknote paper

14

front

16

back

17

Subregions of reduced excitation opacity

18

Subareas of reduced luminescence opacity

19

Subareas of reduced substrate thickness

20

Through register

22, 24

luminescent imprints on the front

26

luminescent imprints on back

30

Luminescence Register image

32, 34, 36

Luminescence image components

33, 35

boundary line

42, 44

luminescent imprints on the front

46

luminescent imprints on back

50

Luminescence Register image

62, 64

luminescent imprints on the front

66

luminescent imprints on back

70

Luminescence Register image

71, 72, 74, 75, 76

Luminescence image components

82,83,84

luminescent imprints on the front

85.86

luminescent imprints on back

87,88,89

R / G / B layers

90

Luminescence Register image

91

Luminescence comparison image

Claims (15)

Data carrier, in particular value or security document, with a translucent substrate (12) having a front side and a rear side; wherein in a first region (1) luminescent material (22) is applied on the front side of the substrate (12);
wherein in a second region (2) luminescent material (26) on the back of the substrate (12) is applied;
wherein the first region (1) and the second region (2) are arranged in register with each other; and
wherein for the viewer when excitation (8) from the front a luminescence image (30) is generated in phantom, which comprises an image portion (32) of the first region (1) and a laterally to the image portion (32) of the first region (1). comprising adjacent image portion (36) of the luminescent second region (2);
wherein 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 intensity of the luminescent material is selected differently depending on the region. A data carrier according to claim 1, characterized in that the luminescence image (30) is produced for the viewer in the case of front excitation (8) and a recognizable other backside luminescence image is generated in the back excitation, in which 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 components of the two luminescent regions (1, 2) is increased recognizably. A data carrier according to claim 1 or 2, characterized in that the adjoining image portions (32, 34) of the luminescence image (30) have the same brightness value. Data carrier according to one 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 transparent subregion (17, 18). A data carrier according to claim 4, characterized in that the partial region (19) of reduced substrate thickness is formed by a physical removal of substrate material after substrate preparation. A data carrier according to claim 5, characterized in that the translucent substrate is a fiber-based substrate which is produced by means of a sieve, wherein the substrate material is physically removed on the sieve side of the substrate. A 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 generated in the fiber-based production of the substrate watermark, wherein the portion of reduced substrate thickness is preferably additionally transparent. The data carrier according to one of claims 4 to 7, characterized in that the transparent part (18) is luminescence-transparent and / or the transparent part (17) is excitation-transparent. Data carrier according to one 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. Data carrier according to one of the preceding claims, characterized in that the luminescent material (22, 24) is applied with different layer thickness and / or luminescent substance concentration. A data carrier according to at least one of claims 1 to 10, characterized in that the viewer can not see the transition between the two image portions (22, 26) in the luminescence image (30) and / or the composite motif of the luminescence register image (30). only in the case of front excitation in the viewer's view. A 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 layer of a composite substrate. Method for producing a data carrier, in particular according to one of Claims 1 to 12, in which - Providing a translucent substrate; - On the front side of the substrate in a first region and on the back of the substrate in a second region which is registered to the first region, luminescent material is applied; 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 selected differently depending on the region in the two regions,
wherein the two areas form a luminescent read-through register, which generates a luminescent image (30) for the viewer when excited (8) from the front, which image part (32) of the first area (1) and laterally to the image portion (32 ) of the first region (1) comprises adjacent image portion (36) of the luminescent second region (2). A method according to claim 13, characterized in that as a translucent substrate, a paper substrate or a composite substrate is provided with a paper layer and that in the papermaking of the paper substrate or the paper layer, a watermark is formed which forms a portion of reduced opacity. A method according to claim 13, characterized in that a portion of reduced opacity is generated by a physical removal of substrate material after the substrate preparation, in particular by laser ablation or by means of a mechanical cutter, or a portion of reduced opacity is generated by applying a transparentizing agent.

Images