EP1233106B1 - Antifalsification paper and other antifalsification items - Google Patents

Abstract

An anti-falsification article (AFA) comprising at least one anti-falsification element (AFE) with at least one photoluminesent segment (PLS) exhibiting linearly polarized photoluminescence and/or linearly polarized absorption is new. An Independent claim is included for preparation of an anti-falsification article by providing an object with an AFE having at least one segment exhibiting linear polarized photoluminescence and/or linearly polarized absorption.

Description

FIELD OF THE INVENTION

The present invention relates to security paper and Security articles in general, ie articles whose counterfeiting prevents or complicates one or more security elements should be, the security elements with at least one photoluminescent segment linearly polarized photoluminescence. The present invention relates equally to one Method of making such security items as well Methods of using the same.

BACKGROUND OF THE INVENTION

It is commonly known for security papers and General security articles, for example for banknotes, Checks, shares, bonds, ID cards. Passports, driving licenses. Tickets, stamps and similar documents or for example for bank cards, credit cards and the like Security elements are used which have the purpose to prevent the falsification of these objects by unauthorized persons or to complicate (R. van Renesse "Optical Document Security" (1997). Artech House, Boston). Such are equally Security elements used to ensure authenticity or To mark the validity of objects or, more generally, to enable or facilitate the identification of objects.

For example, the use of security threads or - strips which, for example, consist of a metal-coated one Plastic can exist in security papers, in particular wide for use in banknotes and similar securities common. If these security threads or strips, for example be embedded in the security paper and this If necessary, these security elements can then be printed not easily recognized when the object is in Reflection is considered. But they appear as a dark shadow, when the object is illuminated and thus in transmission is observed. In particular, the security against counterfeiting Security articles, for example security papers guarantee many suggestions have been made recently been made to security elements with certain properties provided so that not only the presence of security elements in and of itself, but especially the existence special properties the authenticity of the secured object guarantee (US-A-4,897,300; US-A-5,118,349; US-A-5,314,739; US-A-5,388,862; US-A-5,465,301, DE-A 1,446,851; GB-A-1,095,286). From the For example, DE-A 1,446,851 a security thread is known which has a multi-colored micro-printing; the printing ink can also be fluorescent. With Different colors are printed on this thread so small or so close together that they are not visible to the naked eye can be distinguished and therefore the viewer as monochrome patterns appear. The micro-printing and their different colors can be contrasted with a magnifying glass or of a microscope. A similar Security element is described in GB-A-1,095,286, the in that prior art patent claimed micro-printing consists of signs and patterns. US-A-4,897,300 on the other hand, for example, describes a security paper in which several security threads are embedded with different, luminescent dyes are printed. The latter are colorless or paper colored in the unexcited state therefore not or only barely visible to the viewer. By Excitation, for example by irradiation with ultraviolet (UV) Light, luminesce the security threads, which have a size, which enables detection by the naked eye. additionally result from the overlapping of different colors Security threads characteristic mixed colors. For security of security papers, especially banknotes increase, a security thread or strip is therefore made Plastic so integrated into the paper so that "window" in the Paper surface gives a direct view of parts of the surface of the Release security elements, such as in GB-A-1,552,853, GB-A-1,604,463 or EP-A-0,059,056.

However, it is therefore considered a serious disadvantage of all of these known security elements considered that either the characteristic authenticity features for a layperson relative are difficult to detect or complex devices for detection are necessary or on the other hand simply recognizable authenticity features can be faked relatively easily. On the other hand, it's in the nature of things. that Security articles often after a comparatively short time against new products novel security elements are exchanged, in particular to To aggravate counterfeiting and other abuse. There is therefore a urgent need for new, safe and easily recognizable Security elements for security papers and for security articles as a whole generally.

An interesting solution in this regard is already in WO-A-98 01817 described. There are used as security elements for security objects Photoluminescence polarizers are used, in which the emitted Luminescent light is linearly polarized. This light is through a polarizer viewed through and rotated, the viewer has a light-dark effect due to the polarizer either depending on the rotary position transmitted or not transmitted luminescent light. US-A-5,284,364 uses polarizers for security purposes, but they are "ordinary" polarizers such as λ / 2 plates and no photoluminescent polarizers.

It is an object of the present invention to overcome the drawbacks mentioned to fix known security elements and security papers and others To create security articles of the type mentioned above, which are characterized by safe and distinguish easily recognizable security elements. It is another Object of the present invention, security paper and other security articles to create whose identification is made possible by such security elements or is facilitated or their authenticity or validity by such security elements is marked. Other objects of the present invention are Development of a method of making these security items as well Using the same. The solution to these tasks is in the independent Labeled claims.

DEFINITIONS

The term security element refers to a Example, shaped object of various shapes may have, for example, but not only, fiber, thread, rod, Film, sheet, layer, tape, plate, disc, snippet and / or Combinations of these. The security element can be homogeneous and be continuous and can be structured or patterned and can contain multiple individual elements, zones or pixels.

The term security article refers to objects whose counterfeiting is to be prevented or made more difficult by one or more security elements or whose authenticity or validity is to be indicated by one or more security elements or which are to be identified by one or more security elements, for example, but not only. Banknotes, checks, shares, bonds, ID cards, passports, driver's licenses, entrance tickets, stamps, bank cards, credit cards. The term security paper refers to security items that consist essentially of paper.

Die polare Achse eines linearen Polarisators oder Analysators ist die Richtung des elektrischen Feldvektors des Lichts, welches durch den Polarisator oder Analysators transmittiert wird. Die Polarisationsachse eines Segments oder - wenn singemäss anwendbar - Sicherheitselements odes eines anderen Objekts ist die Richtung des elektrischen Feldvektors des Lichts, welches vom entsprechenden Segment, Sicherheitselement oder anderen Objekt emittiert oder absorbiert wird.

To describe the functioning and properties of segments, safety elements, safety articles and the conditions of experiments, the following, common definitions of different axes are used:

The polar axis of a linear polarizer or analyzer is the direction of the electric field vector of light that is transmitted through the polarizer or analyzer. The polarization axis of a segment or - if applicable as appropriate - security elements or another object is the direction of the electric field vector of light which is emitted or absorbed by the corresponding segment, security element or other object.

In this document, a segment is a part of an object, in particular a security element, on which the characteristic degree of polarization and the polarization axis for the emission and absorption are adequately determined can be.

In this document the degree of polarization for the emission is expressed by the dichroic ratio in emission . The dichroic ratio in emission is defined as the ratio of the integrated photoluminescence emission spectra measured, with unpolarized excitation, by a linear polarizer whose polar axis is arranged parallel and perpendicular to the polarization axis of the examined segment.

In this document the degree of polarization for absorption is expressed by the dichroic ratio in absorption . The dichroic ratio in absorption is defined as the ratio of the absorptions measured at the excitation wavelength by a linear polarizer (analyzer) whose polar axis is arranged parallel and perpendicular to the polarization axis of the examined segment.

In this document, the excitation wavelength is defined as the wavelength that is used for optical excitation for the photoluminescence of the security element or its photoluminescent segments. The terms absorption and emission refer to optical processes.

DESCRIPTION OF THE FIGURES Figure 1:

Dichroic properties of a film made of 2% by weight EHO-OPPE / UHMW-PE with a draw rate of 80 (in the referred to below as material A). Above: Polarized absorption spectra, recorded for incident Light which is parallel (solid line) and perpendicular (dashed line) is polarized to the polarization axis of the film. Below: Polarized emission spectra under isotropic excitation at 365 nm, measured by a polarizer (analyzer) with its polar axis parallel (solid line) and perpendicular (dashed line) polarized to the polarization axis of the film.

Figure 2:

Graphic representation of the dichroic ratio in absorption and the dichroic ratio in emission for a number of previously known, partly for use in Security elements according to the present invention suitable photoluminescent materials with linearly polarized Emission, as a function of Draw rate (shown in the graph), composition and chemical structure of the luminescent dye.

Figure 3:

Simplified graphic representation of security articles according to of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is based on our surprising Discovery that photoluminescent materials are what by linearly polarized photoluminescence with a dichroic Ratio in the emission of 5 or more are marked and in can bring a shape according to the invention, security elements can be manufactured, which for the production of Security papers and security articles in general can be used. In particular, we discovered that the security papers according to the invention and Security articles in general through great counterfeit security and distinguish easily recognizable authenticity features.

The fact that certain luminescent materials linearly polarized absorption and emission behavior as such known for a long time; these effects was initially in inorganic crystals (E. Lommel, Ann. d. Physik and Chemistry, Vol. 8. pp. 634-640 (1879))) and later in oriented Filming mixtures of ductile polymers and luminescent dyes observed (A. Jablonski, Acta Phys. Polon., Vol. A 14, pp. 421-434 (1934)). Since then there have been countless Materials that are characterized by linear Characterize polarized absorption and emission (J. Michl et al. "Spectroscopy with polarized light" (1986). VCH Publishers, New York) for example, oriented blends of ductile polymers and oligomeric, photoluminescent materials with significant uniaxial component (M. Hennecke et al., Macromolecules, Vol. 26, pp. 3411-3418 (1993)), oriented, photoluminescent Polymers (P. Dyreklev et al., Adv. Mat., Vol. 7, pp. 43-45 (1995)) or mixtures of photoluminescent and ductile polymers (US -A-5,204,038; T. W. Hagler et al., Polymer Comm., Vol. 32, pp. 339-342 (1991); Ch. Weder et al., Adv. Mat., Vol. 9, pp. 1035-1039 (1997)), liquid crystalline systems (N. S. Sariciftci et al., Adv. Mater., Vol. 8, p. 651 (1996); G. Lüssem et al., Adv. Mater., Vol. 7, p. 923 (1995)) or oriented, photoluminescent materials based on orienting substrates have grown (K. Pichler et al., Synth. Met. Vol. 55-57, p. 454 (1993); N. Tanigaki et al., Mol. Cryst. Liq. Cryst., Vol. 267, p. 335 (1995); G. Lüssem et al., Liq. Cryst., Vol. 21, p. 903 (1996); R. Gill et al., Adv. Mater. Vol. 9, pp. 331-334 (1997)). Only recently are photoluminescent materials which is a substantially unpolarized Absorption behavior, but a linearly polarized emission (C. Weder et al., Nature, Vol. 392, p. 261; EP 0933655A1). Likewise, too photoluminescent materials can be obtained which are linear polarized absorption and an essentially unpolarized Emission have EP-A-889350; EP-A-933,655th

According to the present invention, such materials brought into a suitable form and for the production of Security elements are used that make up Have security papers and security articles manufactured. The Security element can have various forms, for Example, but not only, fiber, thread, rod, film, sheet, layer, Ribbon, plate, disc, snippet and / or combinations thereof. Furthermore, security elements in more complex forms, for example, but not only, logos, letters, characters, numbers etc. be used. The surface can also be used, for example of the security element are structured, for example by Printing or embossing. Essential characteristic of Security article according to the present invention is the Fact that the security element is at least one has a photoluminescent segment which is linear polarized photoluminescence with linearly polarized if necessary Absorption is characterized, the segment being a dichroic relationship of 5 or more in the emission.

In the case of photoluminescent segments, it can be from Be an advantage if the suggestion is not or only slightly normal daylight takes place, but, according to a preferred one Embodiment variant of the present invention, an additional Light source, for example in the UV range, is necessary around the To make photoluminescence visible. The linearly polarized Photoluminescence of such segments causes the emitted Light from an external polarizer (analyzer) depending on Orientation of the polar axis of the polarizer (analyzer) and the. The polarization axis of the segment varies is absorbed, for example, when viewed through the naked eye (and of course through the polarizer) to a strong one light / dark contrast can result. Of course, this effect can also can be detected with suitable sensors. Likewise leads the linearly polarized absorption of such segments causes that to be linear polarized excitation light which, for example, by a external light source in connection with a linear polarizer can be generated by the segment depending on the orientation of the Polarization axis of the segment and the polarization direction of the Excitation light, is absorbed to different degrees, which is the case with the Viewing through the naked eye to a strong light / dark Contrast can result. In this document, a part becomes a segment an object, in particular a security element, at which the characteristic degree of polarization for the emission and the absorption can be adequately determined. It is obvious to a person skilled in the art that the shape and size of this Segments may differ from case to case and the Polarization measurements with various experimental Arrangements, for example conventional spectrometers, microscopic methods etc.) can be done. Is considered Security element, for example, a uniaxially oriented film from Dimensions 5 cm x 5 cm x 2 µm from material A (see example A) If necessary, the entire film can be used as a segment be considered when measuring the degree of polarization in the can be done essentially at any point and from it in Framework of measurement and production accuracy essentially but comparable results with regard to the degree of polarization Polarization axis can be obtained. On the contrary, Example, a fiber shaped into a circle with a Diameter of 0.5 mm and a length of 20 cm from the same Material can be considered as a combination of many segments, because the polarization axis in this determined from polarization measurements Case has a strong dependence on location. Of course shows this element also optical effects, analogous to the above described and in the sense of this invention, which by a Combination of individual segments can be described.

The security elements in security articles according to the present invention suitably contain one or more luminescent dyes which cause the polarization properties according to the present invention. Suitable luminescent dyes can be found, for example, in EP-A-0933655 and EP-A-0889350 and in the publications and patents cited in these patent applications. As can be seen from the experiments which follow, certain oligomers and polymers, for example poly (2,5-dialkoxy- p -phenylene ethynylene) derivatives, such as EHO-OPPE and O-PPE or poly ( p -phenylene vinylene) Derivatives such as (poly (2-methoxy-5- [2'-ethyl-hexyloxy) - p -phenylene vinylene] (MEH-PPV) are very useful for preferred embodiments of the present invention:

Suitable methods for the production of security elements for use according to the present invention are for Example in EP-A-0933655 and EP-A-0889350 and those cited in these patent applications Find publications and patents. As through the following Experiments, the security elements, or segments of such security elements, for use in security articles according to the present invention for example through the anisotropic deformation of ductile Mixtures are made.

It is readily apparent to the person skilled in the art that it is suitable for the Security papers and other security articles according to the present invention are innumerable exemplary embodiments. Yes the In principle, the idea of the present invention can, but not only, on all known security articles and security papers transmitted, which have at least one security element that apart from that of the present invention of course from the linearly polarized photoluminescence, absorption or both, is comparable. For example, according to a preferred embodiment of the present invention, Produce security papers involving one or more photoluminescent security threads or strips with Properties embedded according to the present invention become. If there are several such security threads or strips can be used, according to a preferred Embodiment variant of the present invention, too have different emission colors and in certain Patterns, for example in a special arrangement of the Polarization axes. In an analogous way you can the security elements also on a substrate, for example Paper or plastic, are applied, for example by Laminate. In another preferred embodiment variant according to the present invention, the Security elements in the form of fibers, introduced into the substrate or applied to the substrate. Also in this one Design variant can use security elements be advantageous with different emission colors and the fibers can have a wide variety of shapes, for example stretched or curved fibers can be used, which according to the present invention differ can lead to optical effects.

The invention is then illustrated by some examples explained.

Example A. (Outside the invention) Production of suitable luminescent dyes .

The above-mentioned polymers EHO-OPPE, O-OPPE and MEH-PPV were based on the instructions from Ch. Weder (Macromolecules, (1996) Vol. 29, p. 5157), D. Steiger (Macromol. Rapid Commun., (1997) Vol. 18, p. 643) and US-A-5,204,038. Two different EHO-OPPE samples with number average molecular weights, M _n , of 10,000 gmol ^-1 and 84,000 gmol ^-1 (HMW-EHO-OPPE) were used, O-OPPE had an M _n , of 10,000 gmol ^-1 and MEH -PPV had a weight average molecular weight, M _w , of approximately 450,000 gmol ^-1 .

Other materials used .

Ultra high molecular weight polyethylene (UHMW-PE, Hostalen Gur 412, weight average molecular weight ∼ 4 · 10 ⁶ gmol ^-1 , Hoechst AG) was used as the carrier polymer. Xylene (puriss. Pa, Fluka AG) was used as the solvent.

Characterization of security elements, segments and materials for security elements.

The anisotropic photophysical behavior of the Security elements, segments and materials for Security elements, as detailed in our EP-A-0 933 655, by polarized Determines photoluminescence and UV / Vis spectroscopy.

Production of suitable photoluminescent materials with linearly polarized emission and linearly polarized absorption.

Photoluminescent materials with 1 or 2% by weight EHO-OPPE with M _n of 10,000 gmol ^-1 as the luminescent dye and UHMW-PE as the carrier polymer were produced as described above (Ch. Weder et al., Adv. Mat., Vol 9, pp. 1035-1039 (1997)) by pouring a solution containing the luminescent dye (5 or 10 mg) and UHMW-PE (0.5 g) in xylene (50 g) into a petri dish 11 cm in diameter. The resulting gels were dried under ambient conditions for 24 hours and unoriented EHO-OPPE / UHMW-PE films with a thickness of approximately 70 µm resulted. These films were stretched at temperatures of 90-120 ° C. to various stretching rates (λ = length of the stretched film / original length of the film) between 10 and 80. The resulting films had a thickness between 1 and approximately 10 µm.

This experiment was repeated with EHO-OPPE with M _n of 84,000 gmol ^-1 , O-OPPE with M _n of 10,000 gmol ^-1 and MEH-PPV with M _w of 450,000 gmol ^-1 .

The highly stretched samples from this example have one highly polarized absorption and polarized emission on, as Figure 1 for a film of 2 wt .-% EHO-OPPE with a Draw rate of 80 shows. This special material (in the referred to below as material A) (measured at an excitation wavelength of 485 nm) Dichroic ratio in absorption of 57, a dichroic Ratio in emission of 27 and a yellow-green emission color on. An analog film of 1% by weight MEH-PPV with one Draw rate of 80 (material in the examples below B), however, points (measured at a Excitation wavelength of 510 nm) a dichroic ratio in Absorption of 21, a dichroic ratio in emission of 27 and an orange-red emission color on The Influence of Draw rate, structure of the luminescent dye, Composition of the material and excitation wavelength on the dichroic absorption and emission properties are in figure 2 summarized. This example shows how suitable photoluminescent materials with linearly polarized Emission and linearly polarized absorption can be made from which security elements or segments of such Security elements, for use in security articles according to of the present invention.

Example 1.

A security paper was produced by embedding a strip of 1 mm width and a thickness of approximately 2 μm made of material A ( 2 ) in a paper ( 1 ) with the dimensions 17 cm x 7 cm, so that the polarization axis of the strip is parallel to the short sides of the paper was oriented (Figure 3a). The paper ( 1 ) was printed ( 3 ) and the stripe ( 2 ) was neither clearly visible in normal daylight nor in normal room lighting, neither in reflection nor in transmission by the naked eye. On the other hand, the green-yellow photoluminescence of the strip ( 2 ) could be recognized immediately by the naked eye when the security paper was irradiated with a UV lamp (Bioblock, VL-4LC, 4 Watt). If the security paper was viewed under this radiation by an external linear polarizer (Polaroid HN32) and this was rotated so that its polar axis was either parallel or perpendicular to the short side of the paper ( 1 ), the naked eye saw a strong light / dark Contrast can be seen in the photoluminescence of the strip ( 2 ). An analogous effect could be obtained if the light from the UV lamp was polarized with a polarizer (Polaroid HNP-B) and this was rotated so that its polar axis was either parallel or perpendicular to the short side of the paper (1).

Example 2.

Example 1 was repeated, but in addition a second strip of 1 mm wide and about 2 μm thick made of material B ( 4 ) was embedded in the paper ( 1 ), so that the polarization axis of this strip ( 4 ) parallel to the long sides of the Paper ( 1 ) was oriented (Figure 3b). The paper ( 1 ) was printed ( 3 ) and the stripes ( 2 and 4 ) were neither easily recognizable in normal daylight nor in normal room lighting, neither in reflection nor in transmission by the naked eye. On the other hand, the green-yellow and orange-red photoluminescence of the two strips ( 2 and 4 ) could be immediately recognized by the naked eye when the security paper was irradiated with a UV lamp (Bioblock, VL-4LC, 4 watts). If the security paper was viewed under this radiation using an external linear polarizer (Polaroid HN32) and rotated so that its polar axis was either parallel or perpendicular to the short side of the paper ( 1 ), the naked eye saw a strong bright / dark contrast in the photoluminescence of the two stripes ( 2 and 4 ) and essentially either the yellow-green ( 2 ) or the orange-red ( 4 ) stripes visible. An analogous effect could be obtained if the light from the UV lamp was polarized with a polarizer (Polaroid HNP-B) and this was rotated so that its polar axis was either parallel or perpendicular to the short side of the paper ( 1 ).

Example 3.

Example 1 was repeated, but instead of the strip, fibers with a diameter between approximately 30 and 400 μm and a length between approximately 1 and 10 mm made of material A ( 5 ) were embedded in the paper ( 1 ) (FIG. 3c). The paper ( 1 ) was printed ( 3 ) and the fibers ( 5 ) could not be seen either in normal daylight or in normal room lighting, neither in reflection nor in transmission by the naked eye. On the other hand, the green-yellow photoluminescence of the fibers could be recognized immediately by the naked eye when the security paper was irradiated with a UV lamp (Bioblock, VL-4LC, 4 watts). If the security paper was viewed under this radiation by an external linear polarizer (Polaroid HN32), and this was rotated, a strong light / dark contrast in the photoluminescence could be seen for each individual fiber ( 5 ). An analogous effect was obtained when the light from the UV lamp was polarized with a polarizer (Polaroid HNP-B) and this was rotated.

Example 4.

A security card was produced by laminating a 0.5 mm wide and about 2 µm thick strip of material A ( 7 ) onto an opaque card ( 6 ) made of yellow colored PVC with the dimensions 8 cm x 5 cm, such that the polarization axis of the strip ( 7 ) was oriented parallel to the short sides of the card ( 6 ) (Figure 3d). The strip ( 7 ) was not easily visible to the naked eye in normal daylight or in normal room lighting. In contrast, the green-yellow photoluminescence of the strip ( 7 ) could be recognized immediately by the naked eye when the card was irradiated with a UV lamp (Bioblock, VL-4LC, 4 watts). If the card ( 6 ) was observed under this radiation by an external linear polarizer and this was rotated so that its polar axis was either parallel or perpendicular to the short side of the card ( 6 ), there was a strong light / dark contrast by the naked eye can be seen in the photoluminescence of the strip ( 7 ).

Example 5.

Example 4 was repeated, but instead of opaque card ( 6 ) made of yellow colored PVC, a transparent card made of polycarbonate ( 8 ) was used and in addition a second 0.5 mm wide and about 2 μm thick strip of material B ( 9 ) was laminated on, so that the Polarization axis of this second strip ( 9 ) was oriented parallel to the long sides of the card ( 8 ) (Figure 3e). The green-yellow and orange-red photoluminescence of the two strips ( 7 and 9 ) can be recognized immediately by the naked eye when the card ( 8 ) has been irradiated with a UV lamp (Bioblock, VL-4LC, 4 watts). If the card ( 8 ) was observed under this radiation by an external linear polarizer (Polaroid HN32), and this was rotated so that its polar axis was either parallel or perpendicular to the short side of the card ( 8 ), the naked eye felt that strong light / dark contrast can be seen in the photoluminescence of the two strips ( 7 and 9 ) and essentially either the photoluminescence yellow-green ( 7 ) or the orange-red ( 9 ) strip is visible. An analogous effect could be obtained if the light from the UV lamp was polarized with a polarizer (Polaroid HNP-B) and this was rotated so that its polar axis was either parallel or perpendicular to the short side of the card ( 8 ).

Claims (16)

1. A security item comprising at least one security element having at least one photoluminescent segment with a linearly polarized photoluminescence, characterised in that the segment has a dichroic ratio of 5 or more in emission.
2. The security item according to Claim 1, characterized in that this segment has a dichroic ratio of 10 or more in emission.
3. The security item according to one of the preceding Claims, characterized in that the segment shows linearly polarized absorption.
4. The security item according to one of the Claims 1 to 3, characterized in that the security element is in a form selected from the group consisting of fibers, threads, strips, films, sheets, layers, tapes, plates, disks, chips and/or combinations thereof.
5. The security item according to one of the Claims 1 to 4, characterized in that, apart from the security element, it consists substantially of paper.
6. The security item according to one of the Claims 1 to 4, characterized in that apart from the security element, it contains one or more synthetic polymers.
7. The security item according to one of the Claims 1 to 6, characterized in that the security element can be excited to luminescence by irradiation with electromagnetic radiation at a wavelength between 200 and 400 nm.
8. The security item according to one of the Claims 1 to 7, characterized in that the security element includes at least one carrier polymer and one luminescent dye.
9. The security item according to one of the Claims 1 to 8, characterized in that the luminescent dye is an at least partially conjugated polymer.
10. The security item according to one of the Claims 1 to 9, characterized in that the luminescent dye is a poly-(p-phenylene-ethynylene) derivative.
11. The use of the security item according to one of the Claims 1 to 10 for objects whose counterfeiting is to be made difficult or impossible.
12. The use of the security item according to one of the Claims 1 to 10 for objects whose authenticity and/or validity is to be identified.
13. The use of the security item according to one of the Claims 1 to 10 for objects whose identification is to be permitted and/or simplified.
14. The use of the security item according to one of the Claims 1 to 10 for an object from the group consisting of bank notes, checks, stocks and bonds, identification cards, passports, driver's licenses, admission tickets, stamps, bank cards, and credit cards.
15. A method of producing security items according to one of the Claims 1 to 10, which comprises an object being provided with a security element which contains at least one photoluminescent segment with linearly polarised photoluminescence, characterised in that the segment has a dichroic ratio of 5 or more in emission.
16. A method of producing security items according to Claim 15, characterized in that the segment shows linearly polarized absorption.

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