DE102017127923A1 - An encoding system for forming a security feature in or on a security or value document or a plurality of security or value documents - Google Patents

Abstract

The invention relates to a coding system for forming a security feature in or on a security or value documents, comprising different, stimulable in the non-visible spectral range and emitting in the visible spectral phosphors and / or can be created from them fluorescent combinations, wherein the phosphors and / or fluorescent combinations in a predetermined excitation in each case have different emission spectra in the visible spectral range, so that each of the phosphors and / or phosphor combinations is characterized by at least one individually distinguished emission line and / or emission band, resulting from the individually awarded emission lines and / or emission bands of the other phosphors and / or fluorescent combinations differs, wherein the coding system comprises at least three phosphors, wherein the at least three phosphors and / or created from these phosphors Leuchtstoffkombina tions in the form of at least three luminescent security elements for the security feature j are applied, and each of the luminescent security elements of the security feature is perceived at the predetermined excitation color identical or the same color.

Description

The invention relates to a coding system for forming a security feature in or on a security or value document or a plurality of security or value documents. Furthermore, the invention relates to a security feature, which is designed in the form of several security elements. Moreover, the invention further relates to a security or value document comprising a security feature according to the invention.

Background of the invention

Luminescent organic and / or inorganic materials have long been used in a variety of ways as security features in security and value documents, such as banknotes, passports, identity cards, driving licenses, etc., but also in product protection.

From the GB 1 143 362 A and the GB 1 186 251 A It is known to use combinations of inorganic and / or organic rare earth-activated phosphors emitting in particular in the visible or infrared spectral range in security or value documents in order to produce luminescence codes with their aid. For the sake of reliable recognition of the codes, phosphors were selected in the listed publications, which are characterized by comparatively large spectral distances between the individual emission lines.

Also from the DE 103 46 685 A1 It is known that the spectral distance between the individual emission lines of the phosphors used for the realization of a coding system should be at least 10 nm. As a major advantage over the hitherto known prior art, the use of exclusively emitting outside the visible spectral range phosphor pigments is considered in the last-mentioned document.

Object of the invention

Both in terms of security and value printing as well as in the field of product protection, there is an increasing interest in the application of "public security features" (Level 1 features, which are manageable by sight and feel without additional devices) and at the use of level 2 optical effects based on the increasing general availability of simple handsets for optical stimulation (for example in the form of easy-to-use UV or infrared LEDs) as safety features more and more by "ordinary citizens" and can be evaluated.

Some of the luminescent security elements belonging to this feature class are already found in countless security and value documents (passports, ID cards, theater cards), although such "quasi-level 1" features often lack the necessary security against counterfeiting.

It is therefore desirable to use in exclusive security and value documents exclusive luminescent security features that can be made visible with simple tools, but at the same time beyond the visual impression would include more extensive information.

In particular, it is desirable if these luminescent security features also have a level 3 security characteristic in addition to their level 2 functionality, which could be the provision of machine readable codes. Such codes could be used for verification of authenticity, nominal value coding or even for sorting, for example of different types of banknote denominations or value products.

The invention is based on the technical problem of providing a coding system for forming a security feature in or on a security or value document and a system for forming security features in the form of security elements in which a visualization of the security features is possible with the aid of simple excitation sources and simultaneously an increased and required counterfeit security is provided.

The technical object is achieved by a coding system according to claim 1, a security features according to claim 19 and a security or value document according to claim 20. Advantageous embodiments of the invention will become apparent from the dependent claims.

definitions

Luminescence is the electromagnetic radiation emitted by a physical system in the transition from an excited state to the ground state. Depending on the conditions of excitation and the spectral range of the emitted electromagnetic radiation, different types of luminescence are distinguished (for example, photoluminescence, cathodoluminescence, X-ray luminescence, electroluminescence, etc.).

Photoluminescence here refers to the type of luminescence in which the excitation takes place with the aid of UV radiation and the resulting luminescence radiation is emitted in the visible spectral range (VIS, approximately 380 to 780 nm).

Anti-Stokes luminescence (up-conversion) is a special case of luminescence, with multi-level IR-induced excitation also causing emission in the visible spectral range.

Phosphors are organic or inorganic chemical compounds that exhibit luminescence upon excitation with electromagnetic or particle radiation or upon excitation by electric fields. In order to make this possible, activator and optionally additionally coactivator ions acting as radiation centers are incorporated into the phosphor base gratings (phosphor matrices) formed by the chemical compounds. Frequently these phosphors are present as solids, in particular in the form of luminescent pigments.

An emission spectrum describes the spectral distribution of the electromagnetic radiation emitted by the phosphors or of the light emitted by them. Such an emission spectrum can consist of emission lines and / or emission bands.

A code is generally a mapping rule for the assignment of characters, symbols or measurable properties to a character set. In the case of luminescence codes, the measurement data to be assigned results from the spectral sequence of the emission lines and / or emission bands of the selected phosphors and / or phosphor combinations, which as a rule are determined by the wavelengths of the emission maxima (λ _max values), the intensity ratios between the selected emission lines and and / or bands and possibly also by the half-widths of these emissions can be characterized.

The CIE standard valence system (also known as the CIE standard color system) is a three-dimensional colorimetric system defined by the Commission Internationale de I'éclairage (CIE) in 1931, which allows the description of colors and self-illuminants through the X, Y and Z standard color values. These result from linear, additive evaluation of the respective emission spectrum with one of the three standard spectral value functions x (Λ) y (λ) and z (Λ).

The terms "CIE standard valence system" and "CIE standard color system" are used equivalently to each other in the present invention.

The CIE color coordinates x, y and z denote the ratios of the standard color values X, Y and Z to their sum. The representation of the color coordinates x and y gives the two-dimensional standard color chart, which then no longer contains the brightness information. Due to the physiology of the eye, different spectral distributions can lead to identical color coordinates.

The CIE normal valence system is based on the definition of an ideal normal observer whose spectral value functions are the standard spectral value functions x (Λ) y (λ) and z (λ) correspond. Colors and luminescent materials (such as phosphors) that have the same color coordinates are called color identical.

Color perception and color perception of an individual observer may differ from those of the defined normal observer.

Color discrimination is the measure of perception of color differences by individual viewers.

Thus, for example, the so-called MacAdam ellipses describe tolerance ranges in the standard value table, which are distinguished by the fact that the color differences of different colors based on different x, y coordinates are not perceived by defined observers and with a certain probability by individual observers. It can thus be given a tolerance for the color differences for the perceived color uniformity, which can be color value dependent.

Maximum permissible color differences in the sense of perceived color uniformity can be determined by surveys of test persons. Such studies are referred to as psychometric measurements that determine the likelihood of perceiving a color difference. Two color samples are considered the same color if they are rated as indistinguishable from a sufficiently large group of observers under the given excitation conditions with a defined probability. Measuring methods for this purpose are for example BACKHAUS, WGK KLIEGL, R. WERNER, JS: Color Vision. Perspectives from different Disciplines. Cape. 2.3. "Psychophysics of Color Vision" such as IRTEL, H .: "Methods of Psychophysics" , and in ERDFELDER, E .: Handbook quantitative methods (S. 479-489), physiology publishing Union Weinheim 1996 , described.

The acceptable color differences of the objectively measured color co-ordinates, which are still considered to be the same color by individual observers, can thus be predefined.

The term "color identical" or "color identity" in the present invention is thus understood to mean that two phosphors have identical color coordinates in the CIE standard valence system under predetermined excitation conditions.

The term "equal color" or "color uniformity" is understood in the present invention so that two phosphors under a predetermined excitation, which are within a tolerance color range of the CIE standard color system, such as a MacAdam ellipse, from a sufficiently large group of observers among the predetermined excitation conditions with a specified probability as indistinguishable.

Basic idea of the invention

One aspect of the invention relates to a coding system for forming a security feature in or on one or more security or value documents, comprising various, in the non-visible spectral range, in particular in the ultraviolet or infrared spectral region, excitable and emitting in the visible spectral region phosphors and / or from them producible phosphor combinations, wherein the phosphors and / or phosphor combinations each have different emission spectra in the visible spectral range, so that each of the phosphors and / or phosphor combinations is characterized by at least one individually distinguished emission line and / or emission band, which is distinguished from the individually distinguished Emission lines and / or emission bands of the other phosphors and / or phosphor combinations is different, wherein the coding system comprises at least three phosphors, wherein the mindes at least three phosphors and / or the phosphor combinations created from these phosphors in the form of at least three luminescent security elements for the security feature each at a location of the security or value document or attached, and wherein each of the at least three luminescent security elements is assigned a different Lumineszenzcode and each of the at least three luminescent security elements has identical color coordinates in a CIE standard color system or at least those color coordinates that lie within a tolerance color range of the CIE standard color system, for example a MacAdam ellipse, at the given excitation with the respective assigned luminescence code, such that the luminescent security elements of the security feature are color identical at the given excitation or perceived the same color.

Another aspect of the invention relates to a security feature comprising the same features as the coding system according to the invention.

According to the invention, the object described above is achieved by forming the respective codes in the ultraviolet spectral range (namely at wavelengths between 380 and 315 nm (UV-A), 315 and 280 nm (UV-B) and between 280 and 200 nm ( UV-C)) or in the infrared spectral range (IR, For example, at 950 or 980 nm) stimulable and emitting in the visible range phosphors in each case as security elements, such as corresponding markers, assembled and combined, that at a given optical excitation, for example, with a specific UV radiation source, caused color impressions of various security elements a security feature are perceived by the human eye as the same color. This means that the observer perceives the different, visibly luminescent security elements under the respectively defined excitation conditions, for example in the form of markings which are attached as security features respectively on, on or in a security document, and thus presumably for them spectrally identical, although they actually have different electromagnetic spectra and codes defined over these, which can only be verified by means of a special Lumineszenzmesstechnik.

The security elements of a security feature perceived as having the same color as regards their luminescence can be used in different security or value documents (for example banknotes, identity cards, passports, driver's licenses, etc.) or else in product protection. Color matching appearing but different codes having markers can be used, for example, for the purpose of Nomwertwertcodierung of different currency denominations. On the other hand, however, it is also possible to integrate the marks perceived as color same as security features several times in the same, similar or different designs of one and the same security or value document.

On the basis of model calculations and practical experiments, it was possible to prove that for the realization of color-identical or color-identical security elements it is possible to use phosphors emitting linear or band-shaped phosphors and / or combinations thereof in the visible spectral range. Theoretically, there are countless possibilities for realizing identical x-y coordinates within the CIE standard valence system. The specific choice and the number of phosphors and phosphor combinations used with exclusive narrowband and / or broadband emission depends on the desired color impression, but at the same time also on the respective security claim and on the approved effort for the detection of the emitted luminescence and the verification of the codes.

Furthermore, it has been found that color-identical or color-identical security elements can be produced both with close proximity to one another but also with emission lines and / or emission bands which are further apart. The spectral distance of the individual emission lines is not directly decisive for the desired equal color impression of the emitted luminescence of the individual markings, but very well for the expense which must be operated for reliable spectrometric verification.

Further criteria for the selection of the phosphors for the coding system are, for example, the highest possible luminescence yield, a sufficiently high stability and aging resistance to environmental influences, and a particle size distribution of the luminescent pigments adapted to the selected printing and application methods. These properties are also of great importance, for example, for the manner in which the security elements are used on or in the respective security and value documents, as well as for the secure verifiability over the entire life or service life of the security or value document.

The application of the security elements, for example in the form of markings, for example, by means of conventional printing technologies (gravure, flexographic, offset printing or screen printing method, etc.) or take advantage of other types of coating process, wherein the materials to be coated both paper, different Plastics or even other organic or inorganic substances. Furthermore, it can also be provided to use the security elements via admixtures of the phosphors in plastics, the plastics then being introduced into the security or value document.

To realize color-identical or color-identical security elements, for example in the form of markings, numerous phosphors are available both for excitation with UV radiation and for IR excitation. In particular, in the inventive case of using combinations of multiple phosphors, the resulting emission spectra are usually highly complex. Codes formed by these combinations have a level 3 security level and can be verified only with the help of a powerful and possibly very complex luminescence measurement and with the special or secret knowledge about which of the diverse and different emission lines or bands are used for the evaluation ,

As basic grid (matrix) for the UV-stimulable inorganic phosphors used for the production of the security elements according to invention can be used for example the materials executed in the following: borates (eg LaBO ₃ , SrB ₆ O ₁₀ , CaYBO ₄ , SrB ₄ O ₇ , YAl ₃ B ₄ O ₁₂ , SrB ₈ O _{13 '} Ca ₂ B ₅ O ₉ Br), nitrides (eg CaAlSiN ₃ , Sr ₂ Si ₅ N ₈ , MgSiN ₂ , GaN), oxynitrides (eg SrSi ₂ N ₂ O ₂ , α-SiAlON , β-SiAlON, oxides (eg Al ₂ O ₃ , CaO, Sc ₂ O ₃ , TiO ₂ , ZnO, Y ₂ O ₃ , ZrO ₂ , La ₂ O ₃ , Gd ₂ O ₃ , Lu ₂ O ₃ ), halides and oxyhalides (eg CaF ₂ , CaCl ₂ , K ₂ SiF ₆ , LaOBr), aluminates (eg LiAlO ₃ , SrAl ₂ O ₄ , Y ₃ Al ₅ O ₁₂ , BaMgAl ₁₁ O ₁₇ , CaAl ₂ O ₄ , Sr ₄ Al ₁₄ O ₂₅ ), silicates (eg Ba ₂ SiO ₄ , Sr ₃ SiO ₅ , Sr ₃ MgSi ₂ O ₈ , Sr ₂ MgSi ₂ O ₇ , CaSiO ₃ , Zn ₂ SiO ₄ , Ba ₂ SiO ₄ , Y ₂ SiO ₅ , CaMgSi ₂ O ₆ , Ba ₂ Li ₂ Si ₂ O ₇ , LiCeBa ₄ Si ₄ O ₁₄ , Ca ₃ Al ₂ Si ₃ O ₁₂ ), halosilicates (eg LaSiO ₃ Cl, Ba ₅ SiO ₄ Cl ₆ , Sr ₅ Si ₄ O ₁₀ Cl ₆ ), phosphates (eg YPO ₄ , Ca ₂ P ₂ O ₇ , MgBaP ₂ O ₇ , Ca ₃ (PO ₄ ) ₂ , MgBa ₂ (PO ₄ ) ₂ ), halophosphates (eg Ca ₅ (PO ₄ ) ₃ Cl, Sr ₅ (PO ₄ ) ₃ Cl), sulfides (eg ZnS, CaS, SrS, BaS, SrGa ₂ S ₄ , ZnGa ₂ S ₄ , ZnBa ₂ S ₃ ), oxysulfides (eg Y ₂ O ₂ S, La ₂ O ₂ S, Gd ₂ O ₂ S, Lu ₂ O ₂ S), sulfates (eg Mg ₂ Ca (SO ₄ ) ₃ ), gallates (eg Y ₃ Ga ₅ O ₁₂ , CaGa ₂ O ₄ , Gd ₃ Ga ₅ O ₁₂ ), vanadates (z. YVO ₄ ), molybdate and tungstates (eg CaMoO ₄ , Sr ₃ WO ₆ , La ₂ W ₃ O ₁₂ , Tb ₂ Mo ₃ O ₁₂ , Li ₃ Ba ₂ La ₃ (MoO ₄ ) ₈ ),
or else inorganic substance classes such as, for example, borides, carbides, scandates, titanates, germanates and yttrates. This list is not a restriction, it can also be included in the selection of suitable as luminescent phosphor matrix inorganic solid compounds, other classes of materials or individual compounds.

The activation of the selected basic lattice takes place by the targeted incorporation of one or more foreign ions into the respective luminescent matrix, in which case rare-earth ions and / or ions of transition metals are used for doping or codoping in the case of the luminescent substances excitable in the ultraviolet spectral range and emitting in the visible , These activator and optionally additionally introduced coactivator ions form the radiation centers in the respective base gratings and, in interaction with these, determine the luminescence properties of the inorganic phosphors. Thus, in the case of the exemplary use of trivalent rare earth ions such as Pr ³⁺ , Sm ³⁺ , Eu ³⁺ , Tb ³⁺ , Er ³⁺ , Dy ³⁺ , Tm ³⁺ or of 3d ³ -ions such as Cr ³⁺ , Mn ⁴⁺ after UV excitation usually linear emissions, while in the doping of the exemplified basic lattice with ions such as Mn ²⁺ , Cu ⁺ , Ag ⁺ , Sn ²⁺ , Sb ³⁺ , Pb ²⁺ , Bi ³⁺ , Ce ³⁺ and Eu ²⁺ with high probability emission bands can be obtained.

The conversion of infrared excitation radiation into visible light, effected with the aid of phosphors, is called anti-Stokes luminescence or up-conversion. It only succeeds by providing such phosphor materials which are capable of transforming the exciting IR radiation into the visible spectral range by multi-stage excitation processes. As fundamental lattice of such, according to the invention can be used inorganic phosphors are mainly oxidic compounds (for example, Y ₂ O _3, ZrO _2, La ₂ MoO _6, Lanbo _4, LiYSiO _4), oxyhalides (eg YOCI, LaOCI, LaOBr, YOF, LaOF), Oxysulfides (eg Y ₂ O ₂ S, La ₂ O ₂ S, Gd ₂ O ₂ S, Lu ₂ O ₂ S) and fluorides (eg YF ₃ , LaF ₃ , LiYF ₄ , NaYF ₄ , NaLaF ₄ , BaYF ₅ ) available. To secure a sufficiently high luminescence yield the Seltenerdionenkombinationen Yb ³⁺ -He ^3+, Yb ³⁺ -Tm ³⁺ and Yb ^{3+ 3+} -Ho be used as radiation centers in the anti-Stokes phosphors mostly. However, other phosphors are also known, such as the materials SrF ₂ : Er ³⁺ , YF ₃ : Yb ³⁺ , Tb ³⁺ or CaF ₂ : Eu ²⁺ , which can also be used as IR-VIS radiation converters.

In addition to the inorganic luminescent pigments, it is of course also possible to use in the UV or IR spectral region excitable and visibly emitting organic phosphors, such as different, rare earth-activated organic complex compounds for producing color-identical security elements. These may optionally be combined with selected inorganic luminescent pigments.

Moreover, depending on the particular application, the intended design of the security feature, and the intended technology for fabricating the security elements, photoluminescent inorganic or organic nanoscale phosphors or appropriately configured quantum dots are also suitable as components for providing the requisite phosphor components.

In a particularly preferred embodiment, the phosphors selected for the particular application of the coding system are obtained by deliberately changing the chemical composition of the respective host (basic) lattice, i. by deliberately made substitutions in the cation and / or anion sublattice, modified so that the emission spectra of these exclusive phosphors differ significantly from those of the luminophores used in conventional industrial applications or even those which have been described in detail in the specialist literature. The preferred use of such phosphors with exclusive emission spectra can further increase the anti-counterfeiting security of the value or security documents provided with the coding system.

The coding system according to the invention offers a variety of embodiments for different levels of security and applications. It can be provided color identical or same color markers, the authenticity of which can be tested with simple hand sensors, but also those in which the safe verification of codes high-resolution spectrometers are required. The range of verification options ranges from forensic testing in specialized laboratories to high-speed detection of machine-readable codes.

Special embodiments

An advantageous embodiment of the invention relates to a coding system, wherein the luminescent codes assigned to the luminescent security elements are formed from the different spectral sequence of the individually distinguished emission lines and / or emission bands of the phosphors and / or fluorescent combinations.

A further embodiment of the invention relates to a coding system, wherein the luminescent codes assigned to the luminescent security elements are formed from the intensity ratios of the individually distinguished emission lines and / or emission bands of the phosphors and / or phosphor combinations.

Yet another exemplary embodiment of the invention relates to a coding system, wherein at least one further phosphor and thus further phosphor combinations for the formation of further luminescent security elements with other Lumineszenzcodes is provided.

A particularly advantageous embodiment of the invention relates to a coding system wherein the color coordinates of the luminescent security elements are adjusted via mixing ratios of the phosphors used for phosphor combinations, resulting in defined relative intensity ratios of the individually distinguished emission lines and / or emission bands for the phosphor combination.

Another embodiment of the invention relates to a coding system, wherein at least one of the phosphors comprises an organic phosphor, in particular a rare earth-activated organic complex compound.

An advantageous embodiment of the invention relates to a coding system, wherein at least one of the phosphors comprises an inorganic phosphor.

Another embodiment of the invention relates to a coding system wherein both inorganic and organic phosphors of different particle size, and for example also nanoscale phosphors or quantum dots, and corresponding phosphor combinations are used.

An advantageous embodiment of the invention relates to a coding system, wherein the phosphors are modified by targeted substitutions in the phosphor lattice, so that they have an exclusive emission spectrum.

Yet another embodiment of the invention relates to a coding system, wherein the phosphors and / or phosphor combinations in one or more ultraviolet wavelength ranges, namely at wavelengths between 380 nm and 315 nm (UV-A) and / or at wavelengths between 315 nm and 280 nm ( UV-B) and / or at wavelengths between 280 nm and 200 nm (UV-C) are excitable.

A particular embodiment of the invention relates to a coding system, wherein the luminescent security elements of the security feature at at least two adjustable in the ultraviolet spectral excitation conditions, ie in the UV-A and / or in the UV-B and / or in the UV-C spectral region, are color identical or the same color.

Another embodiment of the invention relates to a coding system, wherein the luminescent security elements of the security feature at each of the predetermined excitations in the UV-A, UV-B or UV-C spectral region are color identical or perceived in the same color.

An advantageous embodiment of the invention relates to a coding system wherein the luminescent security elements of the security feature at different predetermined suggestions have different color coordinates in the CIE standard color system or at least those color coordinates that lie within a different tolerance color range of the CIE standard color system, so that the luminescent security elements are perceived identical in color or the same color at a given predetermined suggestions, but at a different predetermined suggestions a different color identity or Have the same color.

An exemplary embodiment of the invention relates to a coding system, wherein the phosphors and / or phosphor combinations in the infrared wavelength range, namely at wavelengths between 950 nm and 980 nm are excitable.

A further embodiment of the invention relates to a coding system, wherein the maxima of the individually distinguished emission lines and / or emission bands of the phosphors and / or phosphor combinations are only a few nanometers apart, in particular a distance of less than 10 nm, particularly preferably a distance of less than 5 nm, most preferably have a distance of less than 3 nm.

Another embodiment of the invention relates to a coding system, wherein a further information about the manner of the arrangement of the security elements of the security feature, for example about the location or a shape of the security element, for example in the form of a symbol, digit or icon, the security elements assigned.

An advantageous embodiment of the invention relates to a coding system, wherein all color coordinates of the phosphors covered by the coding system lie essentially on a straight line in the CIE standard color system.

Another embodiment of the invention relates to a coding system, wherein the phosphors and / or phosphor combinations have a substantially the same or similar aging resistance.

The foregoing particular embodiments of the invention will be further described in detail below.

The inventive coding system for forming a security feature in or on a security or value document or a plurality of security or value documents is particularly characterized in that it depends on the use of different in the non-visible spectral range, in particular in the ultraviolet (UV) or infrared (IR) spectral range excitable and emitting in the visible spectral range phosphors and / or fluorescent combinations, the phosphors and / or phosphor combinations under predetermined excitation conditions each have different emission spectra in the visible spectral range, so that each of the phosphors and / or phosphor combinations by at least one individually distinguished Emission line or emission band is characterized, which differs from the individually awarded emission lines or emission bands of the other phosphors and / or phosphor combinations differs.

The coding system is further characterized in that it comprises at least three, preferably exclusive, phosphors and / or the fluorescent combinations prepared from these phosphors, which are assembled in the form of security elements to security features and each security element is assigned a code, which from the spectral Sequence of the individually awarded emission lines or emission bands of at least three phosphors and / or phosphor combinations and / or the intensity ratios of these emission lines and / or emission bands is formed.

At the same time, the inventive solution is characterized in that all luminescent security elements assembled to a security feature have identical color coordinates in a CIE standard color system or at least those color coordinates that lie within a tolerance color range of the CIE standard color system, for example a MacAdam ellipse. In this way it can be ensured that all security elements of a security feature according to the invention equipped with luminescence codes are perceived by the viewer as having the same color under defined excitation conditions.

When using exactly three phosphors to form a security feature of the coding system, the color coordinates of the emission spectra of the individual phosphors in the CIE standard color system must as far as possible lie on a straight line in order to combine several of these phosphors be able to provide different Lumineszenzcodes with identical color coordinates. As model calculations and practical experiments have shown, at least three distinguishable codes with exactly identical color coordinates and different spectral sequence of the individually awarded emission lines can be generated in this case, by the combination of in each case two of the selected three phosphors (fluorescent pairs) and by an appropriate tripartite combination ( Phosphorus triplet) can be formed. If, in addition to the spectral characteristic, the intensity ratios between the selected emissions are used for the code setting, further possibilities arise for the formation of distinguishable triple combinations. The exact adjustment of the color coordinates of the individual combinations is bound to specific mixing ratios between the individual phosphors. By contrast, given a triangular arrangement of the color coordinates of three different phosphors resulting from the emission spectra around a predetermined target color coordinate, there is only one possibility for setting the exact target color location. This means that only a single luminescence code could be generated in this way.

However, security elements equipped with luminescence codes can also be perceived by the viewer as having the same color if the respective color coordinates are not exactly identical but are positioned within a tolerance color range of the CIE standard color value system (for example a MacAdam ellipse). Corresponding studies have shown that even with the use of only three phosphors under these conditions, it is possible to provide, for example, up to seven different luminescence codes which are assessed by subjects as the same color. In addition to the spectral sequence of the individual emission lines and / or bands, the differently set intensity ratios between these lines and / or bands must then also be included as characteristic properties in the code formation in this case.

By adding further, preferably exclusively modified phosphors, the possibilities for providing distinguishable luminescence codes can be further increased. It must be taken into account that the number of generated codes also depends, for example, on the specific positioning of the target color location as well as on the permitted spectral distances between the maxima of the individually awarded emission lines and / or bands. In addition, it should be noted that the luminophores which are used in practice, for example modified rare earth-activated phosphors, already have, as individual components, in most cases multiple emission lines and frequently complex line spectra. This also increases the number of possible code assignments at the level 3 security level.

In a further essential aspect of the invention, a method for producing a security feature of a coding system for use in security or value documents as well as in product protection is provided.

In a first step, decisions must be made about the excitation conditions for the inventive luminescence feature, about the desired target color location or a correspondingly defined tolerance color range for realizing the desired color identity of the individual security elements required for the security feature, as well as the number of codes required for authenticity protection become. These decisions depend on the type and use of the value and security documents or products to be protected, on the approved cost of verifying the luminescence codes, and on the design specifications for the feature.

Another step concerns the selection of the phosphors required for the production of the required security elements. The selection may be made on the basis of the measured emission spectra of the phosphors to be evaluated, preferably with exclusive emission characteristics. The CIE color coordinates of the individual luminescent substances, which can be calculated from the emission spectra, provide information as to whether and how many combinations of these luminescent substances are available for realizing the predetermined target color location or a corresponding tolerance color range. In addition, on the basis of these measurement results, the mixing ratios of the components which are important for the production of the phosphor combinations can be calculated in advance.

The subsequent step of the method is directed to the optionally required experimental verification and the setting of the mixing ratios of the creation of the color-identical security elements of the security feature. As a rule, only a few practical tests are required in order to determine, on the basis of the colorimetric calculations carried out, the mixing ratios, valid under application conditions, for the combination of the selected phosphors to color-identical security elements. The experimental verification is required, however, to interactions between the phosphors used and other factors influencing the independent and different optical properties (self-emission, absorption and reflection behavior) of the other organic and inorganic constituents (binders, additives) of the color compositions used for the application of the security feature and the optical effects of the support materials used to be able to take into account.

In a further method step, the applied or incorporation of the selected phosphors and / or phosphor combinations takes place on or in the carrier materials of the respective security or value documents. This process step can be carried out, for example, with the aid of the customary printing processes (gravure printing, flexographic printing, offset printing or screen printing processes, etc.) or else using other coating technologies.

A final step of the method for producing a security feature according to the invention is reserved for the final code assignment. On the basis of the emission spectra of the individual security elements provided with color identical or color identical phosphors and / or phosphor combinations, the appropriate maximum coding emission maxima (λ _max values) of the individually awarded, preferably exclusive emission lines and / or emission bands and such emission lines and / or bands, in which the ratio of the respective luminescence intensities can be regarded as code representing property, selected and assigned to a character set, for example a number or letter sequence.

Furthermore, the essence of the invention is determined by the provision of a method for reading out the luminescence codes and for verifying the authenticity of the security elements of a security feature of the coding system according to the invention, which are designed, for example, as markers. This method comprises: exciting the phosphors and / or phosphor combinations present in the security elements with a predetermined invisible excitation radiation, which is generated in particular by suitable UV or IR radiation sources, detecting the electromagnetic spectra of these phosphors and / or fluorescent combinations in a predetermined visible Spectral range with the help of suitable optical spectrometers, as well as the evaluation of the measurement results and the final authentication, whereby the presence of the deposited code relevant emission characteristics is checked and compared with the deposited code information.

The technical complexity required for the secure verification of the color-identical or color-identical luminescence codes introduced into the individual security features forming the respective security feature of the coding system depends on various factors. These include the breadth of the spectral range to be detected in the visible region and the extent of the complexity of the individual, preferably exclusive emission spectra of the phosphors and / or phosphor combinations used, wherein, in particular, small spectral distances between the maxima of the characteristic emission lines and / or bands relevant for code formation Use of powerful optical spectrometers with a high spectral resolution require.

In addition, another important factor relates to the requirements for the detection speed resulting from the practical application of the security features according to the invention in value and security documents or in product protection. Extensive research has shown that on the basis of the invention, machine-readable level-3 security features can be put together, the luminescence codes of which can be reliably verified both in the ATMs (ATM, Cash Management System) and in the sorting machines of the central banks ,

On the other hand, it is of course quite advantageous in terms of security against counterfeiting, for example, if at least two of the individually awarded emission lines of color-identical security elements are so close together that they can not be distinguished from each other without major technical effort.

The advantage of the invention lies in the great scope for the specific embodiment of belonging to an inventive security feature security elements, which is opened by the many possible combinations of different phosphors. Thus, it can be decided exactly how small the spectral distance of, for example, at least two individually awarded emission lines with regard to the highest degree of security against forgery for each trainee security feature and how small it can be in view of the verification circumstances, for example under conditions of high-speed detection. In an advantageous embodiment of the invention, it is therefore provided that the maxima of at least two of the individually awarded, preferably exclusive emission lines of the security elements belonging to a security feature are only a few nanometers apart in the electromagnetic spectrum, this preferably being at a distance of less than 10 nm, more preferably have a distance of less than 5 nm and, most preferably, a distance of less than 3 nm.

A particularly advantageous embodiment of the invention further consists in the fact that the security elements assembled to security features are perceived by the human eye as the same color not only in a given optical excitation, but at least in another, basically distinguishable from the first optical excitation. As is generally known and already described, the ultraviolet spectral range in the literature and in the technical avertion in the ranges UV-A (380-315 nm), UV-B (315-280 nm) and in the UV-C Radiation range (280-100 nm) divided, with different radiation sources are available for the individual types of radiation defined. In this context, it has surprisingly been found that for the production of a security feature of the coding system according to the invention also those phosphors and phosphor combinations can be selected whose preferably exclusive emission spectra, for example, both in the excitation with UV-A and UV-B radiation sources in the CIE Normal color system identical color coordinates or have those that are within designated tolerance color ranges, so that all equipped with different luminescence codes security elements of the corresponding security feature under both conditions of excitation are perceived by the viewer as the same color.

In addition, it has been demonstrated that, based on the invention, luminescent security elements can also be provided for the change between UV-A and UV-C excitation or for the change between UV-B and UV-C excitation the perceived after the excitation color impressions are retained even when changing the excitation conditions. In a very particularly advantageous embodiment of the invention, the security elements selected for the formation of a security feature of the coding system are color matched by the observer for all excitation conditions that can be set in the ultraviolet spectral range, ie both with excitation with UV-A, UV-B or UV-C radiation sources identified.

The variety of possible variations for the embodiment of the invention is also expressed in that even with a change caused by the change of UV excitation sources change the perceptible color impressions of the security elements, the emission spectra of the selected phosphors and phosphor combinations can be set in an advantageous manner so that the luminescent elements under the respectively defined excitation conditions are evaluated as mutually the same color. This means that the observer perceives all security elements in one type of excitation, for example, as the same color as red and in the other type of excitation, for example, as the same color as green.

In a further preferred embodiment of the invention, the security elements used for the formation of an inventive security feature, which have the same color impressions preferably in the UV spectral region under different conditions of excitation, can also be equipped such that the individually distinguished, required for the formation of the level 3 security codes, and in particular exclusive emission lines and / or emission bands are emitted only in one of the different types of excitation and are therefore available only under these excitation conditions for the authenticity verification.

In order to further increase the security of the security elements, it may be expedient to include further information in the verification. Therefore, it is further provided in a further advantageous embodiment that the coding system forms a further information about an arrangement and / or a contour of the security elements on or in the security or value document. Such an arrangement may for example be a specific position on the security or value document. However, the security element itself can also have a specific contour, for example the shape of a character, a symbol, a number or a pictogram. During verification, the position on the security or value document and / or the arrangement and / or the presence of the corresponding contour of the security element are then additionally checked.

• 1a - e: die Emissionsspektren von drei Modellleuchtstoffen sowie die dazugehörigen Farbkoordinaten, dargestellt in einem CIE- Normfarbsystem bzw. der Normfarbtafel des CIE-Normfarbsystems,
• 2a - f: die Emissionsspektren von Leuchtstoffkombinationen, die aus den in den 1a bis 1e gezeigten drei Modellleuchtstoffen gebildet sind, und deren Farbkoordinaten mit dem vorgegebenen Zielfarbort übereinstimmen,
• 3a - e: weitere Emissionsspektren von drei anderen Modellleuchtstoffen sowie die dazugehörigen - in einem CIE- Normfarbsystem bzw. der Normfarbtafel - dargestellte Farbkoordinaten dieser Modellleuchtstoffe,
• 4a - e: die Emissionsspektren von Leuchtstoffkombinationen, die aus den in den 3a bis 3e gezeigten drei anderen Modellleuchtstoffen gebildet sind, und deren Farbkoordinaten mit dem in der 4a gekennzeichneten Zielfarborts übereinstimmen,
• 5a - e: Beispiele für weitere farbidentische Emissionsspektren von weiteren Leuchtstoffkombinationen aus vier Modellleuchtstoffen, wobei die Farbkoordinaten der vier einzelnen Modellleuchtstoffe gemäß 5a in Form eines Vierecks um einen möglichen Zielfarbort positioniert sind,
• 6a - c: beispielhaft drei reale Emissionsspektren von drei ausgewählten realen Leuchtstoffen,
• 7a - e: beispielhaft Emissionsspektren von Leuchtstoffkombinationen, insbesondere Leuchtstoffpaaren und Dreierkombinationen, die aus den in den 6a bis 6c gezeigten drei ausgewählten realen Leuchtstoffen gebildet sind,
• 8 die Farbkoordinaten in der CIE-Normfarbtafel der in den 7a - e gezeigten Emissionsspektren der Leuchtstoffpaare und Dreierkombinationen der drei ausgewählten realen Leuchtstoffen, und
• 9 a & 9 b die Farbkoordinaten in der CIE-Normfarbtafel der in den 6a - c sowie ind den 7a - e gezeigten Emissionsspektren der ausgewählten realen Leuchtstoffe und Leuchtstoffkombinationen sowie einen ermittelten Toleranzfarbbereiche für die beschriebenen realen Leuchtstoffe und Leuchtstoffkombinationen bei unterschiedlichen Anregungsbedingungen, nämlich einmal bei einer 313 nm-Anregung (9a:) und ein anders Mal bei einer 365 nm-Anregung (9a).

The invention will be explained in more detail with reference to preferred embodiments with reference to the figures. Hereby show:

• 1a - e : the emission spectra of three model phosphors and the associated color coordinates represented in a CIE standard color system or the standard color chart of the CIE standard color system,
• 2a - f : the emission spectra of phosphor combinations, which consist of those in the 1a to 1e three model phosphors are formed, and whose color coordinates coincide with the predetermined target color location,
• 3a - e : further emission spectra of three other model phosphors as well as the associated color coordinates of these model phosphors, shown in a CIE standard color system or the standard color chart,
• 4a - e : the emission spectra of phosphor combinations, which consist of those in the 3a to 3e shown three other model phosphors are formed, and their color coordinates with those in the 4a match the designated target color locations,
• 5a - e : Examples of further color identical emission spectra of further phosphor combinations from four model phosphors, whereby the color coordinates of the four individual model phosphors according to 5a are positioned around a possible target color location in the form of a quadrilateral,
• 6a - c by way of example three real emission spectra of three selected real phosphors,
• 7a - e : Exemplary emission spectra of fluorescent combinations, in particular fluorescent pairs and triple combinations, from the in the 6a to 6c shown three selected real phosphors are formed,
• 8th the color coordinates in the CIE standard color chart in the 7a - e shown emission spectra of the phosphor pairs and triple combinations of the three selected real phosphors, and
• 9 a & 9 b the color coordinates in the CIE standard color chart in the 6a - c as well as in the 7a - e shown emission spectra of the selected real phosphors and phosphor combinations and a determined tolerance color ranges for the described real phosphors and phosphor combinations at different excitation conditions, namely once at a 313 nm excitation ( 9a :) and another time with a 365 nm excitation ( 9a) ,

Tab. 1

Lumineszenz-spezifische Daten von drei ausgewählten Modellleuchtstoffen wie sie insbesondere in den 1c bis 1e beschrieben sind,

Tab. 2

Mischungsverhältnisse für die Ausbildung von Leuchtstoffkombinationen, deren Farbkoordinaten mit dem vorgegebenen Zielfarbort übereinstimmen, wie sie in den 2a bis 2j beschrieben sind,

Tab. 3

Lumineszenz-spezifische Daten von weiteren drei ausgewählten Modellleuchtstoffen wie sie insbesondere in den 3c bis 3e beschrieben sind,

Tab. 4

Mischungsverhältnisse für die Ausbildung von Kombinationen der weiteren drei Modellleuchtstoffe, deren Farbkoordinaten mit dem vorgegebenen Zielfarbort übereinstimmen, wie sie in den 4a bis 4e beschrieben sind,

Tab. 5

Lumineszenz-spezifische Daten von vier ausgewählten Modellleuchtstoffen wie sie insbesondere in den 5a bis 5e beschrieben sind,

Tab. 6

Mischungsverhältnisse für die Ausbildung von farbidentischen Kombinationen der vier Modellleuchtstoffe, und

Tab. 7

Farbkoordinaten der ausgewählten drei realen Leuchtstoffe sowie der nach den angegebenen Mischungsverhältnissen aus diesen Leuchtstoffen gebildeten Kombinationen.

In addition, preferred embodiments of the invention will be further described with reference to the following tables, which describe the following, namely:

Tab. 1

Luminescence-specific data from three selected model phosphors as shown in particular in the 1c to 1e are described

Tab. 2

Mixing ratios for the formation of phosphor combinations whose color coordinates match the given target color location, as in the 2a to 2y are described

Tab. 3

Luminescence-specific data of a further three selected model phosphors as shown in particular in the 3c to 3e are described

Tab. 4

Mixing ratios for the formation of combinations of the other three model phosphors whose color coordinates match the given target color location, as in the 4a to 4e are described

Tab. 5

Luminescence-specific data from four selected model phosphors such as those in particular 5a to 5e are described

Tab. 6

Mixing ratios for the formation of color identical combinations of the four model phosphors, and

Tab. 7

Color coordinates of the selected three real phosphors as well as the combinations formed from these phosphors according to the specified mixing ratios.

In the 1a is a schematic representation of the CIE standard color chart 5 of the CIE standard-valency system. The CIE standard valence system has been defined to establish a relationship between human color perception and the physical causes of the color stimulus and typically captures the totality of all perceptible colors, with reference to a defined normal observer.

In addition, show 1a and in particular the enlarged portion in the 1b the x and y color coordinates 10 . 20 . 30 the emission lines of three simulated, possible single luminescent substances in the CIE chromaticity diagram. The enlargement according to 1b that these color coordinates 10 . 20 . 30 in the CIE standard color chart are essentially on a straight line. For clarity, the color coordinates 10 . 20 . 30 with different symbols, namely color coordinate 10 as triangle △, color coordinate 20 as square □ and color coordinate 30 shown as a circle o, where the 1c to 1e then the associated emission spectra (emission lines) 1 . 2 . 3 branch.

Despite the small spectral distances of the emission lines and the small distances of the calculated color coordinates, it is not possible to provide color-identical security elements to form one of the security features using the selected modeled individual luminescent substances. Investigations have shown that an area of the color area spanned by the color coordinates of the emission lines used for simulation purposes is approximately 7 times the closest MacAdam ellipse.

In the 1c to 1e are the emission spectrum used for model calculations 1 . 2 . 3 of the three selected, modeled and narrow-band emitting (notional) phosphors. In other words, they show 1c to 1e the emission spectra corresponding to the x and y color coordinates of the 1b shown color coordinates 10 . 20 . 30 or the symbols △, □ and o. The wavelengths of the emission maxima of the emission lines are for the emission spectrum 1 (△ symbol) at 619.8 nm, for the emission spectrum 2 (□ symbol) at 624.2 nm and for the emission spectrum 3 (◯ symbol) at 626.4 nm very close together. The half-widths of the individually awarded emission lines were set to 1 nm. The characteristic data of the selected model phosphors are summarized again in the following Table 1. Tab. 1 Emission wavelength color coordinates FWHM λ _max / nm x y nm Model Fluorescent 1 619.8 0.691 0.309 1 (Triangle Δ) Model fluorescent 2 624.2 0.699 0.301 1 (Square □) Model Fluorescent 3 626.4 0.703 0.297 1 (Circle ◯)

The 2a and 2 B show again (as well 1a) a representation of the x and y color coordinates 10 . 20 . 30 the emission spectra / emission lines 1 . 2 . 3 of the three simulated, possible single luminescent substances in the CIE standard color chart as already described in the 1 were presented. In addition, there is also a possible defined target color coordinate / destination color location 50 specified and marked with the symbol *.

The in the 2 summarized representations, and the data listed in Tab. 2 show that the possible, predetermined target coordinate or the specified target color location 50 (Comp. 2 B) can be realized by different combinations of the three selected model fluorescent. In this case, several color identical emission spectra 12 . 13 . 123-1 or 123-2 obtained, which can be used to form color-same Lumineszenzcodes. Tab. 2 Target color location (* symbol) x = 0.696, y = 0.304 Mixing ratio / mole fraction /% Phosphor 1 Fluorescent 2 Phosphor 3 Mixture 12 32 68 Mixture 13 50 50 Mixture 123-1 44 27 29 Mix 123-2 46 17 37

The number of color-identical security elements that can be generated in this way depends on whether the code assignment uses exclusively the different spectral sequence of the selected linear emissions or whether the intensity ratios between the individual individually distinguished emission lines are included as a code-forming property. In the first case considered, exactly three distinguishable emission spectra with identical color coordinates can therefore be created on the basis of the selected phosphors. These relate to the pairwise combination of two of the three phosphors ( 2c and 2d) a corresponding triple combination. Examples of the emission spectrum of this one triple combination are in the 2e and 2f shown.
Show here 2c the emission spectrum 12 , which is a combination of a first and a second phosphor. 2d shows the emission spectrum 13 which is a combination of the first and third phosphors and the 2e shows the emission spectrum 123-1 , which stands for a possible triple combination of the first, second and third model phosphor. 2f shows the emission spectrum 123-2 , an alternative three-way combination of the first, second and third model fluorescent material, which is characterized by a different mixing ratio.

Become the different intensity ratios (such as at 2e and 2f) used between the individual characteristic emission lines for code generation, there are other ways to provide color-like emission spectra of different triple combinations by varying the mixing ratios. 2f shows a possible example of a further combination of the emission spectra of the three fictive phosphors, in which the set intensity ratios of the code-forming lines are significantly different from those of the 2e differ.

The 3a to 3e and 4a to 4e and accompanying Tables 3 and 4 (see below) illustrate another possible example of creating a coding system based on three other model phosphors that also have singular emissions and color coordinates that are in turn on a straight line in the CIE color chart. In the 3c to 3e are the emission spectra used for model calculations 1' . 2 ' . 3 ' of the three selected modeled (notional) phosphors. From them, the x and y color coordinates can be obtained 10 ' . 20 ' . 30 ' those in the 3a and 3b the symbols △, □ and o are assigned.

Compared to the ones in the previous ones 1 and 2 described model phosphors have the fictitious phosphors selected for this example significantly larger distances between the different emission maxima. In addition, the half-widths of the model phosphors were adjusted so that both linear (see eg. 3e) as well as banded emissions (cf. 3d) result. From the 3a and 3b As a result of the comparatively large spectral distances, the color coordinates of the example phosphors are also far apart in the CIE standard color chart. The corresponding color impressions show a clear color shift and thus a clear color difference and vary from Gün to red. Tab. 3 Emission wavelength color coordinates FWHM λ _max / nm x y nm Model Fluorescent 1 545 0.268 0.721 13 (Triangle △) Model fluorescent 2 574 0.473 0.526 25 (Square □) Model Fluorescent 3 600 0627 0373 4 (Circle ◯) Tab. 4 Target color location (* symbol) x = 0.433, y = 0.554 Mixing ratio / mole fraction /% Model Fluorescent 1 Model fluorescent 2 Model Fluorescent 3 Mixture 12 ' 31 69 Mixture 13 ' 63 37 Mixture 123-1 ' 22 73 5 Mixture 123-2 ' 47 36 17

In this case too, distinguishable emission spectra can be achieved by selective combination of the phosphors 12 ' . 13 ' . 123-1 ' . 123-2 ' with identical color coordinates (the target color location was again marked with the symbol *, cf. 4a) , and on this basis color identical or at least the same color security elements are created. The 4b and 4c show the emission spectra 12 ' . 13 ' the appropriately configured phosphor pairs, the 4d and 4e the emission spectra 123-1 ' . 123-2 ' of two exemplarily selected triple combinations characterized by different intensity ratios of the individually awarded emission lines and emission bands.

In the pictures of the 5 shows a further example to illustrate the invention, wherein the associated data in Tab. 5 and 6 can be seen. In this case, the emission lines of four fictitious phosphors were compared with those in the 5a represented color coordinates 10 " . 20 " . 30 " . 40 " (again represented with the symbols: triangle △, square □, circle ◯ and circle with cross ⊗) in the shape of a quadrangle around a target color location 50 " (* Symbol) grouped around. At the same time, the positioning of the target color location became 50 " made so that it lies between each two of the assumed color coordinates of the model phosphors, ie on the diagonals of each opposing color coordinates. This results in addition to numerous variants for four-combinations (for example, the 5b . 5d and 5f stand, others are possible) also two emission spectra 13 " . 24 " with a pairwise arrangement of the selected individual emission lines (cf. 5c and 5e) , In the case of different specifications for the target color location, it would also be possible to set a color-identical triple combination at the expense of one of the two-person combination. Tab. 5 Emission wavelength color coordinates FWHM λ _max / nm x y nm Model Fluorescent 1 450 0.156 0.019 15 (Triangle △) Model fluorescent 2 500 0,018 0.529 15 (Square □) Model Fluorescent 3 550 0,305 0.688 15 (Circle ◯) Model Fluorescent 4 630 0.705 0,295 15 (Circle with cross ⊗) Tab. 6 Target color location (* symbol) x = 0.250, y = 0.450 Mixing ratio / mole fraction /% Phosphor 1 Fluorescent 2 Phosphor 3 Phosphor 4 Mix 13 " 27 73 Mix 24 " 74 26 Mix 1234-1 " 19 22 52 7 Mix 1234-2 " 12 41 33 14 Mix 1234-3 " 6 58 16 20

However, the significantly increased number of possible code assignments due to the addition of a further phosphor is mainly caused by the large variety of color-identical quadruplicate combinations with different intensity ratios. It should, however, be borne in mind that, in cases where the spectral order is the same, only the intensity ratios between the combined emission lines or emission bands are taken as the code - forming criterion (see also the 2e and 2f as well as the 4d and 4e) It must be checked whether these intensity relations can be reliably verified under the conditions of practical application. This concerns both the performance of the available detection technology and the question of whether the ratios of the emission intensities of the different individual luminescent substances, which are generally luminescent substances of different chemical composition, also over the entire life cycle of the equipped with the security elements Security and value documents are kept within acceptable tolerance limits. On the one hand, the different aging resistance of the selected phosphors can lead to the color uniformity of the created security elements being lost over the useful life and, on the other hand, to the fact that a code assignment based on defined intensity ratios can no longer be reliably detected in extreme cases.

The 6 to 9 and Tab. 7 describe an example of configuring an inventive security feature based on the use of real phosphors having correspondingly characteristic emission spectra 1"' . 2 '' . 3 '' based. Three inorganic, europium-activated rare earth pigments were selected to produce the required color-matched security elements, and applied in the form of standardized markings (print strips) on a paper base. The emission spectra of these three phosphors measured at a given excitation in the UV-B region (313 nm excitation source) are in the 6 a to 6c shown. The emission spectra 1"' . 2 '' . 3 '' The three real (single) phosphors have an ensemble of several characteristic emission lines. This results in further possibilities for a code assignment, which can affect not only the respective main emission lines of these phosphors, but also different secondary lines.

On the other hand, it turns out 6 however, it is clear that some of the emission spectra 1"' . 2 '' . 3 '' The emission lines encountered by different phosphors are very close to each other or even overlap. In these cases, it must be weighed whether the inclusion of such lines in the code formation makes sense, taking into account the requirement of a secure verification and the costs justifiable for the planned technical application.

In the 7a to 7e are the measured emission spectra (at a 313 nm excitation) 12 "' . 13 "' . 23 '' . 123-1 '' . 123-2 "' and 123-3 "' the proofs of different phosphor combinations (three phosphor pairs and two triple combinations with different intensity ratios) produced under standard conditions at specified mixing ratios (see Table 7). Tab. 7 color coordinates Mixing ratio / mole fraction /% Excitation 313 nm Excitation 365 nm First Fluorescent 1 "' Second fluorescent 2 "' Third fluorescent 3 "' x y x y Fluorescent 1 '" .6690 .3283 .6665 .3240 Fluorescent 2 "' .6737 .3226 .6723 .3215 Fluorescent 3 "' .6740 0.3219 .6724 .3216 Mix 12 "' .6720 .3250 .6728 .3221 20 80 Mixture 13 "' .6710 .3253 .6695 .3216 20 80 Mixture 23 "' .6742 .3224 .6729 .3217 Mixture 123-1 '" .6710 0.3251 .6702 .3216 17 41 42 Mixture 123-2 "' .6723 0.3243 .6172 .3216 11 44 45

Despite the comparatively high complexity, the exemplary emission spectra contain 12 '' . 13 "' . 23 '' . 123-1 "' . 123-2 "' and 123-3 "' numerous sufficiently separate lines and stable intensity constellations to which a luminescence code can be assigned. This concerns both the main emission lines of the individual luminescent substances included in the combinations as well as further lines and characteristic line groupings. Although the sometimes small spectral distances between the coder-relevant emissions are a challenge in terms of spectral resolution and the performance of the detection devices used, it has been found that on the basis of the phosphors and phosphor combinations described in this embodiment, security elements can be provided whose code-forming Emission characteristics can be safely verified even at relatively high readout speeds (for example, in ATMs or in sorting machines from central banks).

Remains the question of the color uniformity of the emission spectra shown 12 "' . 13 "' . 23 '' . 123-1 '' . 123-2 '' and 123-3 "' the exemplary phosphors and phosphor combinations. In the 8th are the ones from the respective emission spectra 12 "' . 13 '' . 23 '' . 123-1 '' . 123-2 "' and 123-3 "' calculated color coordinates 10 "' . 20 "' . 30 '' 130 "' . 230 '' . 1230-1 "' . 1230-2 "' and 1230-3 "' shown in a section of the CIE standard color chart. It becomes clear that these coordinates, as expected, at least tend to lie on a straight line, although they have a clearly perceptible scattering. On the one hand, the high magnification of the selected area of the CIE standard color chart, on the other hand, the fact that the mixing ratios for the provision of the different phosphor combinations were initially chosen comparatively arbitrary, to take into account.

To determine the extent of perceived color differences or perceived color uniformity, further investigations on the basis of the survey of test persons were carried out in the following. The subjects were able, under defined conditions of excitation and viewing, to ascertain the color uniformity or perceived color differences with the exemplary ones Decide on fluorescent and phosphor combinations equipped and available in the form of pressure strips security elements.

The results are in the 9a shown. The 9a shows that the color coordinates of almost all submitted luminescent security features (including those of the individual components 20 '' and 30 '' ) in a tolerance ellipse determined on the basis of the psychometric measurements 51 lie, which means that they were perceived by the subjects with a very high probability as the same color. The only exception is the color coordinate calculated for the single luminescent substance 10 "' which is outside the tolerance ellipse / tolerance color range 51 lies.

A comparable picture is also obtained if the exemplary security elements are not excited at 313 nm (UV-B), but at 365 nm, ie in the UV-A range. Also in this case (cf. 9b) seven of the eight color coordinates of the tested print strips lie within a tolerance ellipse based on scientific research. The shape of the tolerance color range differs somewhat from the range determined for excitation with a 313 nm irradiation source. Nevertheless, the probability that the corresponding security elements are perceived as color identical not only under the selected excitation conditions, but also during a change between the UV-A and the UV-B excitation, can be estimated as very high.

LIST OF REFERENCE NUMBERS

1,1 ', 1 "

Emission spectrum of a first (single) phosphor

2,2 ', 2 "

Emission spectrum of a second (single) phosphor

3,3 ', 3 "

Emission spectrum of a third (single) phosphor

4,4 ', 4 "

Emission spectrum of a further (single) phosphor

5

CIE Standard Color Chart of the CIE Standard Valence System

12,12 ', 12 "

Emission spectrum of a combination of the first and second phosphors

13,13 ', 13 "

Emission spectrum of a combination of the first and third phosphors

23,23 ', 23 "

Emission spectrum of a combination of the second and third phosphors

24,24 ', 24 "

Emission spectrum of a combination of the second and the further phosphor

10,10 ', 10 "

Color coordinates in the CIE standard color system of the first (single) phosphor

20,20 ', 20 "

Color coordinate in the CIE standard color system of the second (single) phosphor

30,30 ', 30 "

Color coordinate in the CIE standard color system of the third (single) phosphor

40,40 ', 40 "

Color coordinate in the CIE standard color system of the further (single) phosphor

50,50 ', 50 "

Target Coordinate / Target Color Location in the CIE Standard Color System

123-1

Emission spectrum of a first triplet combination of the first, second and third phosphors,

123-2

Emission spectrum of another triplet combination of the first, second and third phosphors,

1234-1

Emission spectrum of a first four-combination of the first, second, third and further phosphors,

1234-2

Emission spectrum of another four-combination of the first, second, third and the further phosphor,

1234-3

Emission spectrum of another four-combination of the first, second, third and the further phosphor,

1'"

Emission spectrum of a first real (single) phosphor

2 ''

Emission spectrum of a second real (single) phosphor

3 ''

Emission spectrum of a third real (single) phosphor

4 ' "

Emission spectrum of another real (single) phosphor

12 "'

Emission spectrum of a combination of the first and second real phosphors

13 " '

Emission spectrum of a combination of the first and third real phosphors

24 ''

Emission spectrum of a combination of the second and third real phosphors

123-1 " '

Emission spectrum of a three combination of the first, second and third real phosphors

123-2 " '

Emission spectrum of another three combination of the first, second and third real phosphor

10 " '

Color coordinate for the emission spectrum 1"' of the first real (single) phosphor

20 " '

Color coordinate for the emission spectrum 2 '' of the second real (single) phosphor

30 ''

Color coordinate for the emission spectrum 3 '' of the third real (single) phosphor

120 " '

Color coordinate for the emission spectrum 12 "' a pairwise combination of the first and second real phosphors

130 ' "

Color coordinate for the emission spectrum 13 "' a pairwise combination of the first and third real phosphors

230 ' "

Color coordinate for the emission spectrum 23 '' a pairwise combination of the second and third real phosphors

240 ' "

Color coordinate for the emission spectrum 24 '' a pairwise combination of the second and further real phosphors

1230-1 " '

Color coordinate for the emission spectrum 123-1 "'

1230-2 " '

Color coordinate for the emission spectrum 7123-1 "'

12340-1 ''

Color coordinate for the emission spectrum of a first four-combination

12340-2 ''

Color coordinate for the emission spectrum of a second four-combination

12340-3 ''

Color coordinate for the emission spectrum of a third four-combination

51

Toll tolerance range determined by subject survey in the CIE standard color chart

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• GB 1143362 A [0003]
• GB 1186251 A [0003]
• DE 10346685 A1 [0004]

Cited non-patent literature

• BACKHAUS, W.G.K. KLIEGL, R. WERNER, J.S .: Color Vision. Perspectives from different Disciplines. Cape. 2.3. "Psychophysics of Color Vision" [0024]
• IRTEL, H .: "Methods of Psychophysics" [0024]
• ERDFELDER, E .: Manual Quantitative Methods (p. 479-489), Physiology Publishing Union Weinheim 1996 [0024]

Claims (20)

Coding system for forming a security feature in or on one or more security or value documents, comprising various, in the non-visible spectral range, in particular in the ultraviolet or infrared spectral region, excitable and emitting in the visible spectral emitting phosphors and / or can be created from them phosphor combinations, wherein the phosphors and / or phosphor combinations at a given excitation in each case have different emission spectra in the visible spectral range, so that each of the phosphors and / or phosphor combinations is characterized by at least one individually distinguished emission line and / or emission band, which differs from the individually awarded emission lines and / or emission bands differs from other phosphors and / or fluorescent combinations, characterized in that - the coding system comprises at least three phosphors, wherein the at least three Le in the form of at least three luminescent security elements for the security feature, in each case at a location of the security or value document, and wherein - each of the at least three luminescent security elements is assigned a different luminescence code, and each of the at least three luminescent security elements has identical color coordinates in a CIE standard color system or at least those color coordinates that lie within a tolerance color range of the CIE standard color system, for example a MacAdam ellipse, for the given excitation with the respective assigned luminescence code, such that the luminescent security elements of the security feature at the given excitation are color identical or perceived as the same color. Coding system after Claim 1 , characterized in that the luminescent codes assigned to the luminescent security elements are formed from the different spectral sequence of the individually distinguished emission lines and / or emission bands of the phosphors and / or phosphor combinations. Coding system after Claim 1 and / or 2, characterized in that the luminescent codes assigned to the luminescent security elements are formed from the intensity ratios of the individually distinguished emission lines and / or emission bands of the phosphors and / or phosphor combinations. Coding system according to at least one of the preceding claims, characterized in that at least one further phosphor and thus further phosphor combinations is provided for the formation of further luminescent security elements with other luminescence codes. Coding system according to at least one of the preceding claims, characterized in that the color coordinates of the luminescent security elements on mixing ratios of the phosphors used for phosphor combinations are set, resulting in defined relative intensity ratios of the individually excellent emission lines and / or emission bands for the phosphor combination. Coding system according to at least one of the preceding claims, characterized in that at least one of the phosphors comprises an organic phosphor, in particular a rare earth-activated organic complex compound. Coding system according to at least one of the preceding claims, characterized in that at least one of the phosphors comprises an inorganic phosphor. Coding system according to at least one of the preceding claims, characterized in that both inorganic and organic phosphors of different particle size, and for example nanoscale phosphors or quantum dots, and corresponding phosphor combinations are used. Coding system according to at least one of the preceding claims, characterized in that the phosphors are modified by targeted substitutions in the phosphor lattice, so that they have an exclusive emission spectrum. Coding system according to at least one of the preceding claims, characterized in that the phosphors and / or phosphor combinations in one or more ultraviolet wavelength ranges, namely at wavelengths between 380 nm and 315 nm (UV-A) and / or at wavelengths between 315 nm and 280 nm (UV-B) and / or at wavelengths between 280 nm and 200 nm (UV-C) are excitable. Coding system after Claim 10 , characterized in that the luminescent security elements of the security feature in at least two adjustable in the ultraviolet spectral excitation conditions, ie in the UV-A and / or in the UV-B and / or in the UV-C spectral range, are color identical or perceived the same color. Coding system after Claim 10 , characterized in that the luminescent security elements of the security feature at each of the predetermined excitations in the UV-A, UV-B or UV-C spectral region are color identical or perceived the same color. Coding system after Claim 10 , characterized in that the luminescent security elements of the security feature at different predetermined suggestions different color coordinates in the CIE standard color system or at least those color coordinates, which are within a different tolerance color range of the CIE standard color system, so that the luminescent security elements at a certain predetermined suggestions color identical or be perceived in the same color, but have a different color identity or color balance in another given suggestions. Coding system according to at least one of the preceding claims, characterized in that the phosphors and / or phosphor combinations in the infrared wavelength range, namely at wavelengths between 950 nm and 980 nm are excitable. Coding system according to at least one of the preceding claims, characterized in that the maxima of the individually awarded emission lines and / or emission bands of the phosphors and / or phosphor combinations are only a few nanometers apart, in particular a distance of less than 10 nm, particularly preferably a distance of less as 5 nm, most preferably have a distance of less than 3 nm. Coding system according to at least one of the preceding claims, characterized in that a further information about the manner of the arrangement of the security elements of the security feature, for example, about the location or a form of the security element, for example in the form of a symbol, digit or icon associated with the security elements is. Coding system according to at least one of the preceding claims, characterized in that all the color coordinates of the phosphors covered by the coding system lie essentially in a straight line in the CIE standard color system. Coding system according to at least one of the preceding claims, characterized in that the phosphors and / or phosphor combinations have a substantially the same or similar aging resistance. Security feature in or on one or more security or value documents, comprising various in the non-visible spectral range, in particular in the ultraviolet or infrared spectral, excitable and emitting in the visible spectral emitting phosphors and / or can be created from them phosphor combinations, wherein the phosphors and / or phosphor combinations in a given excitation in each case have different emission spectra in the visible spectral range, so that each of the phosphors and / or phosphor combinations is characterized by at least one individually distinguished emission line and / or emission band, which differs from the individually awarded emission lines and / or emission bands of the other phosphors and / or Fluorescent combinations differs, characterized in that - the security feature comprises at least three phosphors, wherein the at least three phosphors and / or from these Le established fluorescent substances in the form of at least three luminescent security elements for the security feature in each case at a location of the security or value document or attached, and wherein each of the at least three luminescent security elements is assigned a different luminescence code, and - each of the at least three luminescent security elements has identical color coordinates in a given CIE standard color system or at least those color coordinates within a tolerance color range of the CIE at the given excitation with the respective assigned luminescence code Standard color system, such as a MacAdam ellipse lie, so that the luminescent security elements of the security feature at the given excitation are color identical or perceived the same color. A security or value document comprising a document body, wherein the document body, at least one security feature after Claim 19 includes.

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