Object with an identification feature arranged for its identification

Abstract

An object with an identification feature 01 arranged for its identification, wherein the identification feature 01 has at least two identification elements in a defined bounded area, wherein the first identification element is formed from a printing ink or an ink, wherein the second identification element is formed as a random structure formed from pigments 03 of a colorant or as a random structure formed from particles of at least one dye, wherein the random structure of the second identification element is formed as an integral part of the printing ink or the ink of the first identification element, wherein the printing ink or ink of the first identification element applied to a surface of the object to be identified is applied in a grid-like arrangement of pixels 02, characterized in thatthat the pigments 03 of the colorant forming the random structure of the second identification element or the particles of the at least one dye form a planar structure encompassing several adjacent pixels 02 of the grid-like arrangement by coagulation, wherein the grid-like arrangement has at least two types of pixels 02 between which there is a visually perceptible contrast, wherein the pigments 03 of the colorant forming the random structure of the second identification element or the particles of the at least one dye, which form a planar structure encompassing several adjacent pixels 02 of the grid-like arrangement by coagulation, are each formed in pixels 02 of the same brightness.

Description

[0001] The invention relates to an object with an identification feature arranged for its identification according to claim 1.

[0002] Electromagnetic radiation in a wavelength range of approximately 380 nm to 790 nm is generally referred to as the light spectrum and is perceptible to humans as light. However, since the sensitivity of the human eye decreases gradually rather than abruptly at the limits of perception, defining the light spectrum too precisely is not very useful. Furthermore, color perception for individual wavelengths varies slightly from person to person. Therefore, the Commission Internationale de l'Éclairage (CIE) has empirically determined spectral sensitivities for wavelengths and defined a standard colorimetric system to establish a relationship between human color perception (color) and the physical causes of a color stimulus (color valence). The CIE standard colorimetric system encompasses the entire range of colors perceptible to humans.The wavelength ranges adjacent to the light spectrum are ultraviolet radiation in the short-wave range and infrared radiation in the long-wave range.

[0003] In classical electrodynamics, light is considered a high-frequency electromagnetic wave. Ray optics, also called geometric optics, utilizes the approximation that the propagation of light can be visualized by straight rays. This approximation is particularly justified when the dimensions of the object or structure under investigation are large compared to the wavelength of the light. In such cases, all diffraction phenomena can be neglected. Diffraction is the deflection of waves by an obstacle. Through diffraction, a wave can propagate into regions of space that would be blocked by the obstacle if traveling in a straight line. However, diffraction is no longer negligible when geometric structures play a role whose size is comparable to the wavelength of the waves involved. In quantum physics, light is no longer considered a classical wave, but a quantum object.Accordingly, light is composed of individual discrete quanta of energy, called photons. A photon is an elementary particle that always travels at the speed of light.

[0004] When light encounters matter, it interacts with the matter, manifesting itself in one or more of the following phenomena: Absorption: The energy of incident light is absorbed by the matter of a body. This can cause an electron present in the matter to be raised to a higher energy level, and the body to heat up. If the radiation is absorbed by the matter regardless of its wavelength, the body appears black. If only part of the light spectrum is absorbed, the remaining parts of the light spectrum determine the color of the body through subtractive color mixing. When white light strikes a body, the incident light is partially reflected and partially absorbed. If short-wavelength components of the light spectrum above 380 nm are absorbed by the body, the reflected radiation contains predominantly long-wavelength components up to 790 nm and is perceived as red. With predominantly long-wavelength absorption up to 790 nm, the reflected light is perceived as violet. In the case of electronic excitation of matter, energy can also be released again in the form of radiation. This is called spontaneous emission, fluorescence, or – if the process is delayed and / or lasts significantly longer – phosphorescence. Reflection: Light is reflected from reflective surfaces, such as a polished metal surface, according to the law of reflection. The incident light ray, the reflected light ray, and the normal to the surface lie in the same plane. The angle of incidence and the angle of reflection are equal. The ratio of the reflected light intensity to the incident light intensity is called the reflectance and depends on the material and wavelength. Scattering: Light changes its propagation, but unlike reflection, it does not travel in a defined direction; instead, it scatters diffusely in all possible directions. Depending on the scattering body, a distinction is made between Compton scattering (by free electrons), Rayleigh scattering (by bound electrons without energy transfer), Raman scattering (by bound electrons with energy transfer), and Mie scattering (by particles whose size is on the order of the wavelength). Refraction: Light is refracted at an interface between two media of different optical density; that is, a light ray changes its direction at this interface. Some materials split a light ray into two rays of different polarization. This is called birefringence. Optical activity: Certain media rotate the plane of polarization of polarized light. Photoelectric effect: The photons of the incident radiation release electrons from the irradiated body.

[0005] A color stimulus arises from the absorption and remission (i.e., scattering or reflection) of specific frequency components of visible light. The color stimulus is the physical characteristic of the radiation of visible light, which, through direct stimulation of the retina of the eye, evokes a perception that can be experienced as color. The color stimulus can originate from a primary light source, i.e., a self-emitting source, or a secondary light source, i.e., an illuminated object. A color stimulus caused by a primary light source is referred to as light color, whereas a color stimulus caused by a secondary light source is called object color. Object colors alter the spectral composition of the incident light according to the transmission and reflection properties of the matter of the object in question.

[0006] For the color stimulus, a relative spectral radiation distribution S is required. λ Crucially, the "stimulating" radiation depends on its wavelength, not its absolute magnitude or intensity. The spectral distribution that determines color perception is called the color stimulus function φ(λ). In the case of a self-radiating object, this function is equal to its spectral distribution S(λ). In the case of a secondary light source, i.e., a body color, the color stimulus is determined by the product of the radiance factor β(λ) and the spectral distribution of the light source.

[0007] Radiometry is the science of measuring electromagnetic radiation and its applications. The quantitative measurement of radiation intensities is performed using various types of detectors. Detectors used for the physical measurement of radiation quantities are called radiometers. These detectors convert a portion of the radiation into heat or an electrical signal, from which, among other things, the nature of the radiating surface and its temperature can be deduced. Photometry refers to measurement techniques in the wavelength range of visible light and the ultraviolet spectral range using a photometer, where a photometer is an instrument for measuring at least one photometric quantity. Photometric quantities are derived from their corresponding radiometric quantities.The difference between a photometric quantity and its corresponding radiometric quantity lies in the fact that photometry incorporates the observer's sensitivity by multiplying the radiometric quantity by a CIE-standardized spectral luminous efficacy curve, also known as the V-lambda curve. A conventional subscript v (in non-italicized font) for "visual" indicates that the quantity is referenced to visible light, typically the spectral range from 380 nm to 790 nm. The following photometric quantities exist:

[0008] Luminous flux, measured in the SI unit lumen (Im), is the radiant power of a light source weighted by the luminous efficiency curve and corresponds to the radiometric quantity radiant power, i.e., the radiant flux or radiant energy per time, measured in the SI unit watt (W).

[0009] The amount of light, measured in the SI unit lumen-second (Ims), is the radiant energy of a light source weighted by the sensitivity curve and corresponds to the radiometric quantity radiant energy, i.e. the amount of radiation or the energy of a number of photons transported in an electromagnetic radiation assumed to be a stream of photons, measured in the SI unit joule (J).

[0010] Luminous intensity, measured in the SI unit candela (cd), is the luminous flux per unit solid angle, measured at a large distance from the light source, and corresponds to the radiometric quantity radiant intensity, i.e., the radiant power, radiant strength, or radiant flux per unit solid angle, measured in the SI unit watts per steradian (W / sr). Luminous intensity indicates how intensely a light source shines in a particular direction. For a spatially isotropically radiating light source, the luminous flux is equal to the luminous intensity multiplied by 4π, the full solid angle.

[0011] Illuminance, measured in the SI unit lux (Ix), is the luminous flux per illuminated area and corresponds to the radiometric quantity irradiance, i.e., the radiant flux density or radiant flux per effective receiver area, measured in the SI unit watts per square meter (W / m²). 2The illuminance indicates how intensely the area is illuminated.

[0012] The specific luminous radiance, measured in the SI unit lux (Ix), is the emitted luminous flux relative to the size of the light-emitting surface, and corresponds to the radiometric quantity specific radiance or radiant flux density, i.e., the radiant flux per effective emitting area, measured in the SI unit watts per square meter (W / m²). 2 ).

[0013] Luminance, measured in the SI unit candela per square meter (cd / m²). 2 ), is the luminous intensity of a light source, relative to its projected area (perpendicular to the viewing direction), and corresponds to the radiometric quantity radiance, i.e., the radiant flux per solid angle per effective emitter area, measured in the SI unit watt per square meter and steradian (W / (m²)). 2sr)). Luminance is perceived by an image-capturing optical system, e.g., a human or a camera, as the brightness of a light-emitting surface.

[0014] The photometric quantities or the corresponding radiometric quantities can be used to describe the properties of a radiation source, a receiver, and irradiated material.

[0015] An emission spectrum is the electromagnetic spectrum emitted by atoms, molecules, or materials without the input of electromagnetic radiation of the same frequency. The counterpart to an emission spectrum is the absorption spectrum. While discrete energy levels produce a line spectrum, energy bands produce a continuous spectrum. An atomic spectrum is the emission spectrum of a single isolated atom, that is, the intensity of the light it emits as a function of wavelength or frequency. The spectral lines correspond to the energy difference between two different states of the atom. This energy difference is supplied, for example, by an absorbed photon and then released, or emitted, in the form of another photon with that energy. This energy (or, in the spectrum, the line) is discrete and therefore cannot take on arbitrary values.This means that each atom—according to its electron configuration—can only emit particles of discrete wavelengths. The wavelengths of the emitted particles are therefore specific to a particular element. The fact that the "lines" in the spectrum (peaks) are, more precisely, curves with a specific width is due to quantum effects. The spectral lines become wider with increasing gas pressure. At very high pressure, the linewidth can increase so much that a continuous spectrum of light is observed, similar to that seen in a solid. This is caused by the increasingly frequent mutual perturbation of the atoms during collisions. If an electron is completely detached from the atom by the absorption of a photon, this is called ionization of the atom. A certain minimum energy is necessary for this, depending on the initial state of the electron. Since ionization is possible for a continuous energy range above this minimum energy, a continuum is possible. The reverse process, i.e.,The emission of a photon upon capturing an electron is called recombination of the electron with the positive ion. This process produces continuous radiation, the limiting continuum. While the emission spectrum of rarefied gases is a line spectrum, hot solids and liquids emit a continuous spectrum because the individual atoms also interact with each other, causing discrete quantum states to transition into one another. Such a continuous spectrum can be calculated by multiplying the spectrum of a blackbody (Planck's radiation law) at the same temperature by the absorption coefficient for electromagnetic radiation of the "object" at the respective wavelength.

[0016] Solids are defined as matter in the solid state, particularly at a temperature of 20°C. In technical terminology, solids have a certain minimum size, which is not precisely defined. They are therefore macroscopic bodies—in contrast to microscopic bodies such as atoms and molecules. A distinction is made between amorphous (i.e., shapeless on the smallest scale), polycrystalline, and crystalline solids. Polycrystalline solids consist of an accumulation of small single crystals that are randomly arranged to form a larger whole.

[0017] An absorption or absorption line spectrum is an electromagnetic spectrum that arises when broadband, especially white, light passes through matter and light quanta, i.e., photons of specific wavelengths or wavelength ranges, are absorbed (resonance absorption). The absorbed photons are absent from the transmitted light, resulting in the formation of so-called Fraunhofer lines in the spectrum. Therefore, the spectrum is dark or, in extreme cases, black at the relevant wavelengths.

[0018] An absorption band is a wavelength interval in which electromagnetic radiation, such as solar radiation, is selectively absorbed by chemical substances, such as atmospheric gases like carbon dioxide, carbon monoxide, ozone, and methane, on its way to the receiver. The originally continuous spectrum of the radiation source arrives at the receiver with only dark gaps, which form the so-called absorption bands. Certain intervals of the entire wavelength range emitted by the radiation source are now no longer present. A representation of the spectrum obtained through selective absorption is called a band spectrum. An absorption band consists of a large number of individual, i.e., singular, closely spaced absorption lines.Absorption bands arise from the coupling of electrical vibrational and rotational excitation in molecules, so that not a single energy difference is absorbed, but rather, depending on the excitation of the molecules, a whole spectrum of energy values, i.e., the absorption spectrum. The different molecules each absorb only in a wavelength interval specific to them. When photons of electromagnetic radiation emitted by a radiation source are absorbed by exciting atoms, these are sharply defined energy levels and thus wavelengths, and the dark areas are correspondingly narrow lines. In molecules, however, many absorbable energy values ​​often lie close together and form broader dark areas in the spectrum, i.e., the absorption bands. In any case, the observed absorption spectrum is characteristic of the type of matter through which the radiation passes.Therefore, spectroscopy, usually performed in various wavelength ranges, is an important method for analyzing substances. When free atoms, e.g., in a gas or vapor, are spectroscopically analyzed, the photons are re-emitted after absorption, uniformly in all directions. If the light is shone from only one direction, the transmitted light exhibits the absorption spectrum typical for the type of atom present, i.e., for the chemical element in question, as a line spectrum. The light scattered in the other directions shows the corresponding emission spectrum.

[0019] In the spectroscopy of solids, relaxation can occur within the solid between absorption and potential emission. During this process, some of the photon energy is converted into heat, for example. In this case, the absorption and emission spectra are not complementary, as they are for free atoms.

[0020] Luminescence is the optical radiation emitted by a physical system during the transition from an excited state to its ground state. Depending on the type of excitation, different types of luminescence are distinguished. For example, electroluminescence is excited by electric current, such as in light-emitting diodes (LEDs). Photoluminescence is excited by photons, and depending on the time interval between excitation and emission of light, a distinction is made between phosphorescence and fluorescence. Radioluminescence is excited by irradiation with alpha or beta radiation, or by X-rays. Superluminescence arises from optical pumping, in which spontaneously emitted light is amplified by stimulated emission in an optically active medium. Chemiluminescence is excited by a chemical reaction.

[0021] A light-emitting diode (LED) is a light-emitting semiconductor device whose electrical properties correspond to those of a pn semiconductor diode. When an electric current flows through the diode in its forward direction, the LED emits electromagnetic radiation with a wavelength (λ) that depends on the semiconductor material and its doping. This radiation can be either visible light, infrared radiation, or ultraviolet radiation.

[0022] The ability of a solid to absorb light, including semiconductors, depends on the photon energy being absorbed by exciting electrons. Since electrons cannot be excited at an energy difference between a valence band and a conduction band of the solid—that is, within its so-called band gap—the energy of a photon must exceed the energy of the band gap. Otherwise, the photon cannot be absorbed. The energy of a photon is coupled to the frequency of electromagnetic radiation via Planck's constant. Therefore, if a solid possesses a band gap, it is—apart from special effects—transparent to radiation below a certain frequency or above a certain wavelength (λ). The energy of a photon emitted by the solid is equal to the energy of the band gap, i.e., the energy difference between the conduction and valence bands.The energy of the band gap decreases with increasing temperature due to the thermal expansion of the lattice, initially quadratically, then more or less linearly, starting from a maximum value at zero Kelvin. The temperature dependence of the band gap is material-dependent and can be described, for example, by the Varshni formula. The size of the band gap, i.e., the energy gap, determines the energy, i.e., the frequency, wavelength, or color of the radiation or emitted light. It can be controlled via the chemical composition of the semiconductor. For example, the exchange of atoms in the crystal lattice alters the crystalline and / or molecular structure of the material, including its lattice parameters or even its lattice structure. By selectively choosing the semiconductor materials and doping them, the properties of the generated radiation can be varied. In particular, the spectral range and efficiency can be influenced.For example, light-emitting diodes (LEDs) made from the commonly used semiconductor material indium gallium nitride (InGaN) or gallium nitride (GaN) emit light in the ultraviolet (230 nm < λ < 400 nm), violet (400 nm < λ < 450 nm), blue (450 nm < λ < 500 nm), or green (500 nm < λ < 570 nm) spectral range, depending on the doping. LEDs emit light in a limited spectral range Δλ, e.g., a maximum of Δλ = 30 nm; their radiation is therefore almost monochromatic. For example, an LED made of indium gallium nitride (InGaN, InGaN) emits light in the ultraviolet (230 nm < λ < 400 nm), violet (400 nm < λ < 450 nm), blue (450 nm < λ < 500 nm), or green (500 nm < λ < 570 nm) spectral range. x Ga 1-xN), which is a III-V semiconductor formed from the two base materials gallium nitride and indium nitride, produces a band gap at a ratio of 2% indium nitride and 98% gallium nitride that results in near-ultraviolet emission. At 20% indium nitride and 80% gallium nitride, on the other hand, blue-violet radiation with a wavelength of 420 nm is produced. At a ratio of 30% / 70%, radiation with a wavelength of 440 nm is produced, which corresponds to a blue color. Other materials used for light-emitting diodes include, for example, II-VI compounds or the chemical elements silicon (Si) and selenium (Se).

[0023] White light can be generated with light-emitting diodes, for example, using the following additive color mixing methods: a) Different types of LEDs can be used, for example, in one and the same component. Blue LEDs are combined with yellow ones or with red and green ones in such a way that their light mixes well and thus appears white. b) A blue-emitting LED or a UV LED is combined with a phosphor, e.g., in the form of a luminescent layer made of a photoluminescent material or a luminescent dye. This allows short-wavelength, higher-energy light, especially blue light or ultraviolet radiation, to be converted into longer-wavelength light. For example, a blue LED is combined with cerium-doped yttrium aluminum garnet powder. Since blue LEDs have the highest efficiency, while UV LEDs have less than half, this is the most economical method of generating white light using LEDs, but with the disadvantage of a bluish tint to the white light. The ultraviolet component emitted by blue LEDs at the short-wavelength end of their radiation spectrum is also largely converted into yellowish light by the luminescent layer. In one manufacturing process for white LEDs, for example, gallium nitride is epitaxially deposited onto a substrate, e.g.,The first layer of the GaN semiconductor crystal is formed from sapphire or silicon. The light-emitting layer typically consists of InGaN, whose blue light is partially converted into longer-wavelength light by the phosphor. The color of the LED's light is also at least partially dependent on the thickness of the phosphor layer.

[0024] The aforementioned methods for generating white light are described, for example, in WO 2007 / 017049 A1. WO 2007 / 017049 A1 also discloses photonic material with regularly arranged cavities, containing at least one colorant, wherein the wall material of the photonic material has dielectric properties and, as such, is essentially non-absorbing for the wavelength of an absorption band of the respective colorant and is essentially transparent for the wavelength of an emission of the colorant that can be excited by the absorption wavelength, and the cavities are designed such that radiation of the wavelength of the weak absorption band of the colorant is stored in the photonic material.In this process, radiation from the wavelength range of 250 nm to 500 nm is preferably selected and stored in the photonic material, wherein the radiation is preferably selected from the wavelength range of 380 nm to 480 nm and in particular preferably from an indium gallium nitride, especially of the formula In. j Ga j Al k N, where 0 < i, 0 < j, 0 < k, and i+j+k=1. The colorant is an emitter for radiation in the range of 550 nm to 700 nm, preferably a rare-earth compound doped with europium, samarium, terbium, or praseodymium, preferably with triply positively charged europium ions. The colorant is in nanoparticulate form, preferably with a mean particle size of less than 50 nm (hydraulic diameter determined by dynamic light scattering).

[0025] Solid substances that produce visible light when excited with short-wavelength light up to the ultraviolet range or bombarded with electrons are generally called phosphors. Phosphors are often inorganic, crystalline substances that achieve a technically usable luminous efficacy through the targeted introduction of impurities into their crystal structure. Purity levels of up to 99.9999% are required for the starting materials. Phosphors are usually based on oxides or sulfides such as zinc oxide, zinc sulfide, zinc cadmium sulfide, and zinc sulfide selenide, as well as silicates such as willemite and zinc beryllium silicate. Zinc sulfide is also used in self-illuminating radioactive paints. The dopant determines the luminous color (ZnS:Mn → orange-red; ZnS:Ag → blue; ZnS:Cu → green; ZnS:Ln → red to blue-green depending on the lanthanide).Parameters such as the light color of fluorescence and phosphorescence, afterglow duration and energy rendering efficiency depend not only on the materials used, but also on their processing, such as annealing, grinding, quenching, and atmospheric influences during these processes.

[0026] EP 2 062 960 A1 discloses a phosphor, in particular a phosphor used in lighting or light-emitting devices including LEDs, wherein the phosphor essentially comprises a silicate and an activating agent ion and has a main chemical composition which is expressed by the following formula: aAO bA'O cSiO2: xEu yLn zM δN, where A is selected from the group consisting of Sr, Ca, Ba and combinations thereof; A' is selected from the group consisting of Mg, Zn and combinations thereof; Ln is an ion / ions of at least one element selected from the group consisting of Nd, Dy, Ho, Tm, La, Ce, Er, Pr, Bi, Sm, Sn, Y, Lu, Ga, Sb, Tb, Mn and Pb; M is selected from the group consisting of Cl-, F-, B-, I- and combinations thereof; N is selected from the group consisting of Li+, Na+, K+, Ag+ and combinations thereof; a, b, c, x, y, z and δ are molar coefficients; 1.0 ≤ a ≤ 5.0; 0 ≤ b ≤ 2.0; 0.5 ≤ c ≤ 2.5; 0.001 ≤ x ≤ 0.2; 0 ≤ y ≤ 0.5; 0 < z < 0.5; 0 < δ < 0.2; and where 1 ≤ (a+b) / c ≤ 4;and that, when a light-emitting element is excited as an excitation light source with an emission spectrum in the range from UV light to blue light from 240 nm to 475 nm, the phosphor absorbs at least a portion of the light from the excitation light source, thus generating an emission spectrum with at least two maxima in the range from 370 nm to 760 nm, the emissions combining to produce white light. The phosphor is preferably excited by an excitation light source with an emission maximum in the range from UV light to blue-violet light from 240 nm to 455 nm, and this phosphor generates a light emission spectrum with two or three maxima in the range from 370 nm to 760 nm.

[0027] The term "colorant" is, according to DIN 55943:2001-10 "Colorants - Terms", a collective term for all coloring substances. DIN 55943 first divides colorants into organic and inorganic colorants. Each of these two groups is further subdivided into dyes and pigments. Pigments are coloring substances that, unlike dyes, are insoluble in the application medium. The application medium is defined as the substance into which the colorant is incorporated. The properties of pigments are determined not only by their chemical structure but also by their solid-state properties, such as crystal structure, crystal modification, particle size, and particle size distribution.To address the specific optical properties of a dye, we will refer to particles of the dye in question, even if these particles are molecules soluble in the application medium or more complex chemical compounds.

[0028] Dyes specifically absorb a limited portion of visible white light and remit the unabsorbed portion. The dye absorbs the complementary color of the light perceived by the observer. This color absorption is based on conjugated double bonds and the aromatic bases of the molecules. During absorption, conjugated electrons in the double bond system are raised to a higher energy state, and the dye molecule releases energy through radiation at a different wavelength, particularly visible wavelengths, or through heat emission. The absorption range of a dye can be influenced by modifying the functional groups on the aromatic ring. These groups can be nitro, sulfonic, dimethylamino, or hydroxyl groups. This modification can also affect the chemical reactivity and color properties of the dye.Thus, an NH₂ group with its lone pair of electrons has a color-deepening effect. Aromatics, i.e., aromatic compounds or chemical compounds with at least one aromatic core, are a class of substances in organic chemistry characterized by the fact that aromatic molecules possess at least one ring system which, according to Hückel's rule, contains a number of 4n+2 (n = 0, 1, 2, ...) delocalized electrons in conjugated double bonds, lone pairs, or unoccupied p-orbitals. This delocalization leads to a special bonding system in which single and double bonds cannot be distinguished within the ring. In simple, symmetrical ring systems, such as benzene, all bonds are therefore identical. Compared to non-aromatic double bond systems, aromatics are lower in energy and therefore less reactive. In particular, they do not tend to undergo addition reactions.Hückel's rule can be used to determine whether a chemical compound is an aromatic molecule. A cyclically conjugated molecule with [4n + 2] π electrons (an odd number of electron pairs; for example, n = 1, [4x1 + 2 = 6], i.e., three electron pairs) is particularly stable and is called aromatic.

[0029] As mentioned earlier, the absorption of electromagnetic radiation raises the energy level of electrons in molecules or atoms. This means that, approximately, the distance between electrons and their respective atomic nuclei increases. The energy required for this is taken from the incident electromagnetic radiation, such as light. Because these processes occur under quantum conditions, the absorption of electromagnetic radiation is not continuous, but rather occurs in specific steps that correspond to the energy difference between the electrons before and after absorption. This energy difference is inversely proportional to the absorbed wavelength of the incident light and thus determines the color in which the pigment appears.

[0030] The property of a substance to act as a colorant is thus rooted in its chemical structure. Molecules with σ-bonds absorb electromagnetic energy in the X-ray and UV range. Molecules with electrons in π-bonds, i.e., in unsaturated bonds, are excited by electromagnetic waves (or photons) even at lower energies. Interactions of this kind in the long-wavelength UV and especially in the visible range of light trigger the color stimulus.

[0031] In a molecule with multiple conjugated unsaturated bonds, the π electrons can be "smeared out," i.e., delocalized. This reduces the energy gap between the excited state and the ground state, shifting the absorption or emission maximum towards longer wavelengths. The absorption region becomes longer-wavelength with a greater number of such conjugated unsaturated bonds.

[0032] There are organic and inorganic chromophores, i.e., color carriers. Organic chromophores consist of systems of conjugated double bonds, as in carotene, and / or large aromatic molecules, as in methyl red. Inorganic chromophores are frequently found among the transition metals. Examples include vanadium, chromium, manganese, iron, cobalt, nickel, and copper. Depending on their oxidation state and complex formation, these elements can exhibit very different colors. A chromophore, therefore, is the part of a colorant that is responsible for its fundamental color.

[0033] Chromophores are molecular structures whose vibrational properties can be significantly influenced by auxochromes (electron donors) and antiauxochromes (electron acceptors), which further shift and / or polarize the delocalized π-electrons of the chromophore. Auxochromes and antiauxochromes increase the resonance within the molecule by shifting electrons toward or away from a chromophore. Thus, the absorption spectrum of a chromophore alone does not necessarily lie in the visible region of the electromagnetic spectrum. However, if the chromophore is further modified by the resonance effect of a substituent, its absorption spectrum typically shifts as well.

[0034] Chromophores are therefore those basic structures that contain delocalizable electrons. The type of chromophore influences the hue of the dye via its absorption maximum, while the abundance of chromophores influences the color depth. The following molecular structures, in particular, act as chromophores: RC=CR; RN=NR; R-NO2; RC=O; RC=NH; RN=O

[0035] The following functional groups, in particular, act as auxochromes or antiauxochromes: a) Auxochromes: R-OH; RO-R'; R-NH2; R-NH-R'; R-NHCO-R' b) Antiauxochromes: R2-C=O; R-NO2; R-CHO, R-COOH; R-SO3H; RC=NR' The color properties of colorants are thus justified. a) in the molecular structure of the dye itself, b) in its molecular and atomic vibrations, c) in the concentration of the colorant as well as d) in its binding state on or in the respective application medium.

[0036] The way in which the colorant binds is partly determined by the application medium, which acts as a substrate or carrier, for example. The binding of the colorant to a solid or the distribution of a dye in a solution can change the hue, a phenomenon utilized in solvatochromism. Solvatochromism describes the influence of a solvent on the color of a dye. The observable color of the solution is based on interactions between the dye and the solvent molecules, as well as on the mutual interactions of the solvent molecules.

[0037] Functional colorants fulfill a specific, defined function in their application that is not solely based on aesthetic coloration. For example, an indicator dye is a functional colorant.

[0038] Based on knowledge of the color absorption of aromatic or polyunsaturated compounds according to Hückel's rule, special colorants can be produced which a) Absorb light at a specific wavelength and convert the absorbed light into heat, b) Re-emit light at a different wavelength, e.g. as phosphorescent markers or e.g. in the form of fluorescence or chemiluminescence, c) change the polarization direction of the light, e.g. in frequency doubling or as optical switches, d) cause electrical phenomena, e) enable photochemical processes.

[0039] One application medium of particular interest for colorants is printing inks used in printing technology. Printing inks are mixtures of substances containing colorants that are transferred to a substrate, primarily using a printing plate, where they form a layer that dries. Printing inks are suitable for coloring surfaces in technical and industrial processes so that images and text can be displayed. Printing inks consist of dispersed, i.e., typically extremely finely divided, pigments, binders, and organic solvents. Black printing ink contains pigments made from carbon black, especially carbon black. Colored pigments are obtained from minerals or produced chemically.

[0040] The printing ink is intended to reproduce a required color tone on a substrate, whereby the color tone can be specified as a color point within a color space. The optical properties of a printing ink depend on the printing process used for ink application, the substrate, the viewer's position, and the light source under which the printed product is viewed.

[0041] The mechanical properties of printing inks are also called rheological properties. Printing inks for printing processes where ink application is achieved by rollers, such as offset, letterpress, or gravure printing, require good ink transport across the ink rollers and low aerosol formation. Ink transport is determined by the ink's tack. Tack is the force required to separate an ink film. It is a complex relationship between viscosity, cohesion, and adhesion and is measured as tack in ink testing. Aerosol formation is the creation of ink mist and threads at high printing speeds. These aerosols are undesirable. Aerosol formation is strongly temperature-dependent, as it correlates directly with viscosity.

[0042] Printing inks consist of: a) Colouring agents, i.e., made from pigments or dyes, for colour, b) Binders, mainly consisting of resins (solid resins, alkyd resins), to fix the colorants to the substrate, c) Auxiliary substances for adjusting the rheological properties, e.g. to influence drying, gloss or surface hardness.

[0043] Since the layer thicknesses of the printing inks applied to the substrate are very thin (typically about 1 µm to 8 µm, preferably 0.7 µm to 2.5 µm in offset printing), particularly strong pigments are used. Most printing inks consist of a dispersion (actually: suspension) of pigments in a carrier fluid and are therefore a heterogeneous mixture consisting of a liquid and finely dispersed solid particles.

[0044] Pigments are organic, inorganic, or synthetic crystalline powders. Organic pigments are derived from petroleum and used to produce printing inks such as cyan, magenta, yellow, and spot colors. Organic pigments have low temperature stability. Inorganic pigments are mostly special carbon blacks for black inks and titanium(IV) oxide for opaque white. Carbon black is, by definition, inorganic. Most inorganic pigments are characterized by the fact that they do not chemically react with atmospheric oxygen, making them extremely resistant to aging and allowing them to retain their color for virtually any length of time. Finely ground metallic pigments are used for metallic effects. Silver effects are achieved using aluminum bronze. Gold effects are produced by using brass bronze or aluminum bronze with yellow / orange pigment. Fluorescent colors are created using UV-active pigments in the printing ink. Pigments are insoluble in printing ink and are generally harmless to health.Radioactive luminescent materials are not classified as pigments, even though they are insoluble in the application medium. They are self-luminescent, emitting light not through UV radiation or daylight, but through radioactive excitation.

[0045] Dyes produce purer colors than pigments because they emit light with a narrower spectrum. Dyes are soluble in water, alcohol, and fats at a molecular level. However, dyes tend to fade under the influence of UV radiation, meaning they are not as colorfast as pigments. Furthermore, most dyes are toxic and therefore unsuitable for coloring everyday objects.

[0046] The pigments in the printing ink are dispersed, i.e., finely divided, in the binder, i.e., in a dispersing agent. The binder ensures good wetting of the individual pigments and prevents them from clumping together to form agglomerates. During printing, the binder binds the printing ink to the substrate and determines its viscosity.

[0047] A typical offset printing ink contains pigments in a mass fraction between 12% and 18%.

[0048] Pigments typically originate as primary particles, particularly angular ones. These primary particles can clump together across their surfaces to form aggregates. Agglomerates are formed when primary particles and / or aggregates are connected via their respective corners and / or edges. During the dispersion process when the pigments are incorporated into the application medium, the pigment agglomerates are broken down. This results in smaller agglomerates, aggregates, and primary particles. These are then wetted, if present, by a dispersing medium or agent. Ideally, this process distributes them statistically throughout the application medium.

[0049] For applications in safety engineering, for example, color pigments belonging to the class of retinal proteins have been disclosed through WO 00 / 59731 A1 and WO 2012 / 083469 A1. An important representative of the retinal proteins is bacteriorhodopsin (BR). The BR protein consists of 248 amino acids arranged in seven approximately parallel alpha-helices that span a cell membrane and form a pore. A retinal molecule bound to the protein is located within this pore. Retinal is the chromophore of the molecule and is bound to the amine group of the amino acid Lys216 via an imine bond, usually referred to in this context as a Schiff base. Under physiological conditions, the chromophore exists only as the all-trans and 13-cis isomers. Isomerization occurs upon exposure to light. BR forms two-dimensional crystalline regions in the cell membrane of Halobacterium salinarum, assembled into trimers.These regions, up to five micrometers in size, in which BR trimers are arranged in a two-dimensional hexagonal pattern within the lipid bilayer, are called purple membranes (PM). The embedding of BR in the purple membrane results in remarkable stability of the protein against physicochemical influences. Thus, the color and photochemical activity of the PM are retained in the presence of oxygen as well as in the dry state.

[0050] BR can be viewed as a light-energy-driven molecular machine that pumps protons. Initiated by the light-induced isomerization of the chromophore and driven by changes in the proton affinities of amino acid groups, protons are moved from a cytoplasmic to an extracellular side through the protein pore in a multi-step process. The trigger for this directed proton transfer is the isomerization of the retinal chromophore due to light absorption. In the unilluminated state, the chromophore exists as a mixture of all-trans and 13-cis retinal; after illumination, it exists solely in the 13-cis configuration. This results in structural changes to the protein due to the chromophore's embedding, which directly affects the initially protonated state of the Schiff base.Following isomerization, this proton is in an energetically unfavorable environment and is released extracellularly to the immediate interaction partner of the Schiff base, Asp85. This triggers a sequence of four further unidirectional proton transfers before the protein's initial state is restored and a new cycle can begin. This light-driven proton pumping is linked to a cyclic sequence of spectroscopically distinguishable protein states. This sequence is called the photocycle. The completion of the photocycle upon illumination is associated with a reversible color change from purple (B state, absorption maximum 570 nm) to yellow (M state, absorption maximum 410 nm).

[0051] In the aforementioned WO 00 / 59731 A1, a method for ensuring the authenticity of objects has been described in which a photochromic preparation in the form of an ink containing bacteriorhodopsin as a photochromic component is applied to the object, whereby the irradiation of this photochromic preparation with light in the visible wavelength range leads to a change of state that is detectable for the purpose of authenticity testing.

[0052] Ink is an intensely colored liquid used, for example, in word processing or product labeling. Ink consists of a solution or dispersion of colorants in water or another solvent and contains little or no binder. Inks without binders are therefore not printing inks. There are various types of ink, such as inks with soluble or insoluble colorants, water-soluble inks, solvent-based inks, or pigmented inks. Pigments, unlike dyes, cannot chemically dissolve in the application medium. While pigments have a characteristic inherent color, the color of a dissolved dye can depend on the solvent used, meaning the ink may have a different color than the dried ink coating. The dye particles from the ink of the first identification element are, for example,contained in a mass fraction of between 1% and 15% in the ink in question.

[0053] WO 2012 / 083469 A1 discloses a method for verifying the authenticity of a security feature, in particular on a security document, wherein the security feature shows a change in the visible area when stimulated by a flash of light, wherein at least one first image of the unstimulated security feature is taken with a mobile phone, wherein the mobile phone has a camera with an integrated flash function, wherein at least one second image of the security feature stimulated by the flash function is taken with the same mobile phone, wherein the sequence of the two aforementioned images can also be reversed.The mobile phone then performs an authentication check using at least two images and a suitable data processing program, and the result of this check is output via a display or an acoustic interface on the mobile phone.

[0054] In photography, a flash is a lighting device that illuminates the subject with a flash of light at the moment of exposure. An electronic flash unit is a flash unit integrated into, for example, a data acquisition device or an image acquisition device, such as a camera or mobile phone, such as a smartphone. It operates using a flash lamp based on a gas discharge tube. Electronic flash units typically use xenon-filled flash tubes. When the flash is triggered, a capacitor, previously charged to several hundred volts (e.g., a cylindrical electrolytic capacitor or a flat, plate-shaped polymer capacitor), is discharged, creating a very short, bright gas discharge inside the flash tube. Depending on the power and control circuitry, the typical duration of this flash ranges from approximately 1 / 300 to 1 / 40,000 of a second.The emitted spectral range of a xenon-filled flash tube extends continuously from the ultraviolet range through the visible range to the infrared range, with a particularly high radiation intensity in the wavelength range e.g. between 300 nm and 500 nm or between 880 nm and 1,000 nm, depending on the design of the flash tube.

[0055] Alternatively, mobile phones and smartphones use LEDs, preferably power LEDs, as flash units, e.g., a flash LED from the Luxeon product line by Philips Lumileds Lighting Company, San Jose, California, USA, or from the Oslux or Ceramos product lines, both by OSRAM Opto Semiconductors GmbH, Regensburg, Germany. These flash LEDs typically have two spectral maxima, namely at approximately 440 nm (blue) and at approximately 570 nm (yellow), which results in at least approximately white light for an observer through additive color mixing.

[0056] WO 2013 / 054290 A1 discloses a security element or security document comprising a carrier and at least one first feature with a dynamic effect affixed to the carrier, wherein the dynamic effect occurs due to excitation by illumination with a selected wavelength or wavelength band and generates an optical spectral response, wherein the optical spectral response dynamically changes between several color appearances during excitation by illumination over an observable period of time, wherein the first feature with the dynamic effect is located in an area of ​​the carrier that is close to an adjacent feature affixed to the carrier, wherein the adjacent feature has a color impression that is selected such that this color impression reinforces and / or complements at least one color impression of the first feature with the dynamic effect.This dynamic effect is preferably caused by a pigment such as that described in WO 2007 / 005354 A2, which exhibits more than one color impression under uniform, continuous irradiation with electromagnetic radiation.According to WO 2007 / 005354 A2, such a pigment comprises a core with a carrier substance and either a fluorescent material or a phosphorescent material, wherein the core has a substantially spherical shape, and wherein a shell surrounding the core is provided, the shell containing photochromic material which exhibits a first optical property in the radiation of a first light source and a second optical property in the radiation of a second light source, wherein the second light source contains a set of wavelengths not sufficiently present in the first light source, and wherein the second optical property attenuates radiation emitted by the fluorescent or phosphorescent material. The first optical property is, for example, substantially transparent. The second light source includes, for example, ultraviolet wavelengths.

[0057] WO 2015 / 114 540 A2 discloses a method and a material for passively preventing scanner-based reproduction processes.

[0058] EP 2 637 145 A1 proposes a method for authenticating and / or identifying a document or article in which circularly polarizing liquid crystals are contained in a printing ink in a stochastic distribution, i.e., random distribution. The authenticity of the document or article is verified by means of circular polarization of incident light caused by the liquid crystals. Such liquid crystals have a cholesteric phase with a nematic order and a continuously rotating preferred orientation. This results in a helical superstructure with a periodicity typically of a few hundred nm. The continuously twisted optical medium thus acts as a one-dimensional photonic crystal with a photonic band gap for circularly polarized light with the same handedness as the helical order.Cholesteric liquid crystal films therefore exhibit selective reflection of circularly polarized light. In contrast to reflection from metallic or dielectric mirrors, the handedness of the circular polarization is preserved in cholesteric liquid crystal films.

[0059] German patent applications DE 103 04 805 A1 and WO 2004 / 070667 A2 each disclose a method for producing security markings in which the security marking contains a random pattern. The security marking is formed, for example, by the reflective surface of the object to be marked. Alternatively, the security marking is formed by particles, such as colored particles, pigments, effect pigments, sand, dust, crystals (e.g., salt crystals of different colors), ferromagnetic, magnetizable, permanent magnetic, fluorescent, phosphorescent, iridescent, opalescent, or radioactive particles. The random pattern, which is particularly machine-readable, is applied to a product or a label. A fingerprint in the form of a data record containing the individual characteristics of the pattern is extracted from a scanned random pattern.This fingerprint is stored individually for each security badge. During authentication, the fingerprint is extracted again and its match with the stored fingerprint is verified.

[0060] The subsequently published DE 10 2014 207 318 A1 discloses an identification feature with several identification elements arranged in a defined area for the identification of an object, wherein in a first operating state of the identification feature, a first identification element is visually recognizable by irradiation of the area having the identification elements with visible light and a second identification element is not visually recognizable, wherein the second identification element is designed as a random structure formed from pigments or a random structure formed from particles of at least one dye.wherein in a second operating state of the identification feature, at least the random structure of the second identification element is visually recognizable by irradiation of the surface having the identification elements with electromagnetic radiation different from that of the first operating state, wherein the first identification element is designed as an arrangement of characters and / or meaning carriers belonging to a code, wherein each of the characters or meaning carriers of this arrangement is designed as a raster graphic consisting of pixels, wherein the pigments or the particles of the at least one dye of the second identification element are contained in a printing ink or ink, wherein the pixels of the first identification element are formed from this printing ink or ink.

[0061] EP 2 887 268 A1 discloses methods for generating embedding codes for mobile phone information, information embedding methods and reading methods for this purpose.

[0062] Suitable particles for safety markings include organic and inorganic materials, particularly inorganic fluorescent particles such as those offered by Leuchtstoffwerk Breitungen GmbH (98597 Breitungen, www.leuchtstoffwerk.com). Crystals are also well-suited, for example, plate-shaped crystals, liquid crystals, reflective pigments consisting of at least two layers with different refractory indices, and effect pigments (interference pigments, pearlescent and metallic pigments). Effect pigments are offered, for example, under the trade names Iriodin® / Afflair® and Colourstream® by Merck KGaA, Darmstadt, and under the trade name Helicone® by Wacker Chemie, Burghausen.A particular advantage of reflective particles is that a) unlike fluorescent particles, they are subject to virtually no wear from light, and b) different random patterns emerge depending on the viewing and illumination angle. Such changes arise, for example, when viewing the effect pigments because each individual pigment acts like a microscopic mirror for light of a specific wavelength, reflecting this light in its random spatial orientation, thus creating three-dimensional random patterns. The particles used, for example, have a diameter between 0.1 µm and 1 µm, between 1 µm and 10 µm, between 10 µm and 80 µm, between 80 µm and 150 µm, or between 150 µm and 2000 µm, and a thickness of up to 50 µm, preferably up to 10 µm, and particularly preferably up to 3 µm. The particles are preferably embedded in a matrix (carrier).The resulting mixture is used to coat objects. Suitable matrices include paints and varnishes, preferably water-based, solvent-based, powder, and UV varnishes, epoxy resins, plastics (e.g., polyethylene), ethyl acetate and similar materials, paraffins, waxes, and wax-like coatings (e.g., flexanes). The particles can also be incorporated into printing inks. Preferably, these are printing inks for screen, gravure, flexographic, and offset printing, with an ink layer thickness of ≤20 µm, preferably ≤10 µm, particularly preferably ≤5 µm, and most preferably ≤3 µm. The concentration of the particles in the matrix, expressed as a weight percent, is between 0.01% and 30%, preferably between 0.01% and 1%, between 1% and 10%, and between 10% and 30%, particularly preferably between 0.01% and 1% and between 10% and 15%.

[0063] A stochastic distribution, i.e. a random distribution of optically active particles in a layer with readable information for authentication and / or identification of a security feature, is also described, for example, in WO 2006 / 078220 A1, wherein these particles preferably have a length in the range between 10 nm and 500 µm.

[0064] Similarly, US 2001 / 0010333 A1 describes random patterns with optically detectable colored fibers or threads to make an object unique and thus identifiable after illumination with a light source by detecting the optical pattern of the object, e.g. by means of a photosensor.

[0065] WO 2007 / 131043 A2 also discloses an object to be authenticated, comprising a substrate and a mark on the substrate. The mark contains a luminescent material distributed in a random pattern, exhibiting photoluminescence with a quantum yield of at least 10 percent. The mark includes particles of the luminescent material, distributed in the random pattern. The particles are in the nanometer range in size.

[0066] WO 2013 / 144645 A1 also concerns a method for generating a mark to distinguish between genuine and counterfeit goods, wherein at least one code is applied to a surface, the code being generated randomly so that it exhibits a unique pattern when subjected to a specific type of stimulus. Multiple codes can also be applied. The unique pattern results, for example, from the fact that the position of elements of the code is only visible under UV radiation, that the visible color of the elements of the code is only visible under UV radiation, or that the position and the visible color of the elements of the code are visible under IR radiation.

[0067] Furthermore, WO 2010 / 023243 A1 discloses an identification feature for identifying an object, comprising at least two identification elements, wherein at least one first identification element is defined by at least one defined surface with a defined diffractive surface structure that is detectable by light irradiation in the visible range, and wherein at least one second identification element is provided within an optical detection field that at least partially detects the defined surface of the first identification element, the first and second identification elements being integral parts of the object. Preferably, the at least one second identification element is defined by a random structure in a surface of the second identification element or of the object, wherein the random structure of the second identification element is, for example,The first identification element is integrated into the defined diffractive surface structure. The at least one second identification element is, for example, not visible. To identify the object, the position at which the at least one second identification element is located relative to the at least one first identification element is stored. Furthermore, identification information that is unique to the at least one second identification element is stored. For identification, an image of the first identification element is compared with the stored data.

[0068] German patent DE 28 29 778 A1 discloses a security token, such as a credit or identification card, with individual features. These features are present on or in the card in a random distribution and are physically scannable. To generate a reproducible scan size corresponding to the random distribution of the features, a track is provided on or in the card that can be scanned by optical means and contrasts with its surroundings. The optical properties of this track are modulated by the random distribution of the features that coincide with the track. The features are, for example, absorbing and / or scattering structures in one or more layers of the security token, where the structures are, for example, inclusions in the layers of the security token. The line, for example, has fluorescent particles present in a random distribution that vary in size and their mutual spacing.

[0069] DE 196 11 383 A1 discloses a data carrier with an optically variable security element arranged on its surface, wherein the security element conveys a different optical impression at at least two viewing angles, wherein the data carrier is provided with a substrate layer in at least a partial area, which has at least one authentication feature, and wherein the security element at least partially overlaps this substrate layer, the substrate layer being arranged such that it is not completely covered by the security element in at least one direction. The substrate layer contains, for example, at least one authentication feature from the group consisting of luminescent, metallic, magnetic, electrically conductive materials or optically variable pigments. The substrate layer contains, for example, visually and / or machine-readable information.

[0070] WO 2013 / 034471 A1 discloses a device for recognizing a document, wherein the document has a security feature with wavelength conversion properties, comprising: a) a light-generating device configured to illuminate the security feature with excitation light to cause it to emit light; b) an image-capturing device configured to capture light emitted by the security feature in response to the excitation light in order to obtain an emission image, wherein the image-capturing device is further configured to capture light emitted by the security feature in response to a reference light in order to obtain a reference image; and c) a processor configured to recognize the document based on the emission image and the reference image. The reference light is, for example, aWhite light, in particular daylight, or the light-generating device is configured to generate the reference light, in particular as continuous light during the reference exposure, or the light-generating device is configured to generate reference light pulses as the reference light during the reference exposure. The processor is, for example,The device is configured to compare the emission image with the reference image to obtain a comparison result and to recognize the document based on the comparison result, wherein the reference light in particular has a predetermined wavelength, and wherein the processor is configured to determine a wavelength difference between the predetermined wavelength and at least one wavelength of the emission light, or a temporal wavelength profile of the emission light with respect to the predetermined wavelength, in particular a temporal profile of a wavelength amplitude or wavelength differences, in order to obtain the comparison result. The device is preferably a mobile communication device, in particular a smartphone, wherein the light-generating device is an LED flash unit of the mobile communication device, and wherein the image-capturing device is a digital camera of the mobile communication device.Alternatively or additionally, the device comprises a transceiver unit configured to transmit the emission image, the reference image, or a comparison result of a comparison of the emission image with the reference image via a communication network to a remote server for document recognition purposes and, in response, to receive a document recognition result. The device includes a control unit for controlling the light-generating device to produce excitation light and / or reference light. The control unit may be programmed and, for example, configured to execute a computer program, which may be application software (APP).The security feature, which exhibits wavelength conversion properties, can, for example, comprise silicate pigments, particularly silicate phosphor pigments, silicate, sulfide, nitride, YAG, TAG, and thiogallate phosphor pigments, which are added to a printing ink. Such a security feature, when stimulated with blue light of approximately 400 nm wavelength, emits a color-shifted light spectrum that may include, for example, green, yellow, orange, and / or red light. An LED whose light emission spectrum includes blue light in a wavelength range between 390 nm and 470 nm can therefore be used to stimulate such a security feature. Document recognition can thus be performed using a standard smartphone equipped with an LED flash unit.The excitation light can therefore be blue light in a wavelength range of 390 nm to 470 nm, preferably in a wavelength range between 430 nm and 460 nm. The light-generating device can include an LED for generating continuous, flashing, or pulsed light. Upon being excited by the excitation light, the security feature is stimulated to emit light. Due to the wavelength conversion properties of the security feature, which can be achieved, for example, by using a silicate compound such as silicate phosphor, the security feature emits light with a wavelength different from that of the excitation light. The emission recording thus contains information about the wavelength spectrum emitted by the security feature in response to the excitation light.By analogy, the reference recording includes information about a reference wavelength spectrum that can be emitted in response to the reference light by means of the safety feature.

[0071] EP 2 698 404 A1 discloses a group of information used for identification purposes to verify authenticity and identity, wherein the information used for identification is identifiable by an enlargement or enhancement, wherein the group includes a first information element and a second information element, wherein the second information element cannot be identified by any enlargement or enhancement with which the first information element is identified.

[0072] WO 2013 / 060831 A2 discloses a method for marking an article for information coding purposes and as a security feature, comprising a shape memory polymer (FMP) with a visually and / or machine-readable graphic element on the surface of the article, comprising the following steps: a) Pretreating the surface of the article; b) Coloring the surface of the article with a dye solution containing an organic dye and an organic solvent; c) Cleaning and drying the surface of the item; d) Engraving by at least partially removing the surface of the article.

[0073] Shape memory polymers (SMAs) are generally defined as plastics that, after being reshaped, appear to "remember" their previous external shape and thus possess a shape memory. To recall its previous shape, the SMA must be exposed to a stimulus. This stimulus can consist, for example, of an application of heat, either directly or indirectly. Direct heating of the SMA can be achieved externally through hot air, infrared radiation (e.g., exposure to sunlight or the airflow of a hot air blower), or through direct contact with a heat storage medium, such as a previously heated fluid. For example, heat can be applied by immersion in warm water.

[0074] An abstract of the document "Security printing of covert quick response codes using upconverting nanoparticle inks" by Jeevan M. Meruga et al., published by the Institute of Physics (IOP) at the University of the State of South Dakota and the South Dakota School of Mines and Technology on September 11, 2012 in IOP Publishing's Journal Nanotechnology, Volume 23, No. 395201, doi:10.1088 / 0957-4484 / 23 / 39 / 395201, accessed on April 16, 2014 at http: / / iopscience.iop.org / 0957-4484 / 23 / 39 / 395201 / cites, describes a quick response (QR) code printed on a substrate. This QR code is not visible under normal daylight conditions but becomes visible when irradiated with near-infrared radiation. The QR code becomes readable and can then be scanned using a smartphone camera. This QR code is used, for example, to verify the authenticity of banknotes, (valuable) documents, or objects.The QR code can contain a microscopic message that is only readable with a microscope. The QR code is generated using a CAD system. The QR code is made, for example, from a mixture of β-NaYF4 nanoparticles with lanthanides, such as Yb. 3+ / He 3+ and / or Yb 3+ / Tm 3+ ...and green and blue fluorescent inks. The term lanthanides refers to the chemical element lanthanum and the 14 elements that follow lanthanum in the periodic table: cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium. All lanthanides are silvery-lustrous, relatively soft, and reactive metals and belong to the rare-earth metal group.

[0075] The QR code described in the aforementioned abstract is printed onto the substrate using a direct printing process with an aerosol jet printer. Details of an aerosol jet printer are described, for example, in WO 2006 / 065978 A2. An aerosol jet printer first atomizes a printing ink with a viscosity between 1 cP and 1,000 cP into fine droplets with a size of 1 µm to 5 µm, preferably 1 µm to 2 µm, and introduces these droplets into a first gas stream, which transports the aerosolized printing ink to a printhead. A second gas stream, arranged annularly around the first gas stream, is provided at the printhead. This second gas stream collimates the first gas stream, which transports the aerosolized printing ink, to a diameter of, for example, less than 10 µm.Both gas streams exit a printhead nozzle at high speed, directing the print onto the substrate. They transfer fine droplets of ink onto the substrate, which is positioned at a distance of, for example, 1 mm to 5 mm from the printhead nozzle. Such an aerosol jet printer achieves a resolution of less than 10 µm, i.e., more than 2,500 dpi. An aerosol jet printer therefore differs from an inkjet printer in its operation and construction. Differences include, for example, that the size of an ink droplet ejected by an inkjet printer is approximately 30 µm, and the volume of an ink droplet ejected by an inkjet printer is thus about two hundred times greater than that of an aerosol jet printer.An inkjet printer also typically uses printing ink with a viscosity between 8 cP and 12 cP, which is a significantly more limited range compared to an aerosol jet printer.

[0076] A code is an agreement on a set of symbols or meaning carriers for the purpose of exchanging information. The symbols or meaning carriers of a code can be visually readable or haptically perceptible, or they can be not directly usable by humans but readable by a technical device, i.e., machine-readable. A code is, for example, also a visually readable or haptically perceptible script, since a script represents a system of symbols for preserving and transmitting coded information. The symbols of a script can be, for example, alphanumeric characters or other types of characters. The meaning carriers agreed upon for a particular code might be, for example, a pictogram depicting something material or an ideogram representing an abstract concept.

[0077] In inventory management and logistics, various machine-readable codes, particularly optoelectronically readable codes (e.g., those detectable with a CCD or CMOS camera or scanner), such as barcodes, are used for product identification. These codes represent information about a product in a sequence of different characters, such as black and white stripes of varying widths. Two-dimensional codes, also known as 2D codes or 2D barcodes, consist of lines or dots of varying widths with spaces between them, maintaining the highest possible contrast. Unlike one-dimensional barcodes, 2D codes encode data not only in one direction (one-dimensionally) but in a matrix-like arrangement across two dimensions.Examples of 2D codes include the DataMatrix code defined in the international standard ISO / IEC 16022, the QR code according to ISO / IEC 18004, the MaxiCode developed by UPS for the rapid identification, tracking and sorting of packages, and the Aztec code specified in the standard ISO / IEC 24778.

[0078] The two-dimensional QR code consists of a rectangular, usually square, pixel pattern, where the individual pixels or symbol elements are made up of contrasting squares, preferably white and black, and thus represent information content encoded, for example, by a mathematical algorithm, in binary form. A QR code contains at least 21×21 and at most 177×177 symbol elements. A QR code can be read using a smartphone with a camera, in particular a semiconductor camera, and a program designed as a "QR code reader," i.e., a so-called app, whereby the reading is generally omnidirectional. The reading is, in particular, an image interpretation based on the captured contrast values. A QR code arranged on a substrate contains markers at defined locations for detecting its position and orientation.Information regarding the resolution and version of the pixel pattern, as well as the data format of the data stored within it and its error correction capabilities, is also stored at other defined locations within the pixel pattern. An error correction level, selected from a set of permissible levels, is determined during the generation of the respective QR code. Four error correction levels—L, M, Q, and H—determine error tolerance, allowing for the recovery of 7% (level L), 15%, 25%, or 30% (level H) of data that is unreadable, for example, due to damage or faulty manufacturing. Each QR code can encode up to 7,089 numbers or 4,296 characters.

[0079] With reference to an arrangement of characters or meaning carriers belonging to a code, pixels are image elements or picture points to which a color value is assigned in a graphic, especially in a raster graphic, where a raster graphic represents an image in the form of computer-readable data. A raster graphic thus consists of a grid-like arrangement of pixels, i.e., an arrangement in several adjacent columns and rows intersecting these columns.

[0080] Contrast refers to the difference between light and dark areas or colors in an image. Contrast is a distinguishing characteristic of a brightness gradient in an image, or at least between two pixels. Contrast range, or dynamic range, describes the difference in intensity between the brightest and darkest points in an image. Contrast is defined by the maximum and minimum luminance present in the image or between the pixels. According to the Weber-Fechner law, the human eye perceives different luminance intensities not linearly, but logarithmically. For a visual or optical system, such as an eye or a camera, to perceive an object, that object must be sufficiently large and have a sufficiently high contrast. This refers to the limit of visibility, which is reached when objects being viewed, for example,Objects projected onto the retina in the human eye or onto an image sensor in a camera do not distinguish their contours and contrast from the surrounding luminance. This means that the detectability of objects depends essentially on the ability of the visual or optical system to perceive differences in brightness. Therefore, a certain minimum contrast is required to perceive an object, and this contrast is higher in dim ambient light than in brighter light.

[0081] In principle, an object can only be perceived visually if, with regard to the visual or optical system capturing this object, the object simultaneously meets the following four minimum requirements at the time of image capture or recording: a) Minimum luminance b) Minimum contrast c) Minimum size d) Minimum performance duration

[0082] The invention is based on the objective of creating an object with an identification feature arranged for its identification, the identity and / or authenticity of which can be reliably and cost-effectively determined.

[0083] The problem is solved according to the invention by the features of claim 1. Advantageous embodiments and / or further developments result from the dependent claims.

[0084] The advantages achievable with the invention lie particularly in the fact that the claimed identification feature can be mass-produced easily and cost-effectively using a printing process that can be carried out with a printing press. The identification feature contains several identification elements for identifying an object within a defined, limited area, one of which is not visible and thus usually remains hidden from a human observer. A first identification element is preferably designed as an arrangement of characters and / or meaning carriers belonging to a code. In an advantageous embodiment, the first identification element is designed as an arrangement of characters or meaning carriers of a multidimensional code, e.g., in the form of a QR code having a pixel pattern.Such a first identification element can be generated and machine-readable without requiring extensive technical equipment. A standard smartphone equipped with a camera and a QR code reading app (i.e., application software) is sufficient for reading it.

[0085] The second identification element is a random structure formed from pigments or a dye. This random structure only becomes visible and thus photographically recognizable when irradiated with electromagnetic energy of a specific wavelength. The random structure makes the identification feature unique, allowing for easy verification of the authenticity and / or identity of the object bearing the identification feature, for example, by comparison with a previously created sample image. The pigments or at least one dye of the second identification element are contained in a printing ink or dye, so that, for example,Pixels of the first identification element formed from this printing ink or ink can be arranged on the object by means of a printing form-bound printing process or by means of a printing form-less printing process.

[0086] Based on and taking into account the previously given general explanations of scientific and / or technical matters, an embodiment of the invention is shown in the drawings and is described in more detail below.

[0087] They show, for example: Fig. 1. An identification feature with a QR code; Fig. 2. A representation of a random structure within the QR code; Fig. 3. A planar formation of the random structure within the QR code.

[0088] Fig. Figure 1 shows an example of an identification feature 01, preferably formed by a printing device of a printing press, particularly in an inkjet printing process, with several identification elements for identifying and / or authenticating an object bearing this identification feature 01, wherein the identification feature 01 is, for example, arranged on a surface of this object. The identification elements of the identification feature 01 are located within a defined area on or around the object. All identification elements belonging to the identification feature 01 are arranged within the area occupied by the identification feature 01 on the surface of the object.Thus, at least one first identification element and one second identification element are present in this same area, the second identification element functioning as a security feature. The first identification element is preferably configured as an arrangement of characters and / or meaning carriers belonging to a code, each character or meaning carrier of this arrangement being configured as a graphic consisting of pixels, these pixels being formed by applying printing ink or a similar ink to the surface of the object in question. In another embodiment, the first identification element is not used as an information carrier, particularly a machine-readable one, but merely forms the environment for the second identification element.The pigments or particles of the at least one dye of the second identification element are contained in the printing ink or ink. The second identification element, which contains the pigments or particles of the at least one dye, is therefore applied to the surface of the object in question together with the first identification element formed from the printing ink or ink in the same or only a single step. Thus, at the time the identification feature 01 is applied to the surface of the object in question, the second identification element is always a component of the first identification element and cannot be readily separated from it.

[0089] In an advantageous embodiment, the first identification element is designed as a multidimensional code, e.g., as a two-dimensional code having a pixel pattern, in particular as a QR code. In the case of the design as a pixel pattern, the pixel pattern contains at least two contrasting, i.e., relative to each other, optically contrasting forms of pixels 02; that is, at least two different types of pixels 02 are present. For the purpose of optical perception, these pixels 02 in the first identification element are designed in at least two different colors, e.g., in a color pairing such as black / white, blue / yellow, or red / green.Of course, other color pairings or the use of more than two hues are also possible, as long as the hues used exhibit sufficient contrast for optical perception by an optical or visual system. The contrast can be considered sufficient if the different types of pixels 02 are reliably optically perceptible as such by the optical or visual system, e.g., by a data acquisition or image capture device, in particular a scanner or a (semiconductor) camera, e.g., with a CCD or CMOS image sensor, and the different configurations of the pixels 02 are clearly distinguishable from one another. This minimum contrast depends on the design of the optical or visual system used and also on the lighting conditions surrounding the relevant identification feature 01 at the time of data acquisition or image capture.The pixels 02 of the pixel pattern are preferably each designed as a rectangle, in particular as a square. An arrangement of the respective pixels 02 chosen to form the pixel pattern represents information content that is encoded, for example, by a computing unit using mathematical algorithms, and is in particular machine-readable. In the exemplary case shown... Fig. Each of the QR codes 1 to 3 contains a link to the website www.kba.com.

[0090] In a further advantageous embodiment, the first identification element is designed as a visually readable or haptically perceptible character. In particular, the character includes at least one alphanumeric character. In yet another advantageous embodiment, at least one element belonging to the code in the arrangement is designed as a pictogram or an ideogram.

[0091] In the first operating state of identification feature 01, the first identification element is visually detectable by irradiating the surface containing the identification elements with visible light, while the second identification element is not visually detectable. In the second operating state of identification feature 01, the random structure of the second identification element, formed from pigments or particles of at least one dye, which is arranged on the object within the same defined area as the first identification element, is visually detectable by irradiating the surface containing the identification elements with electromagnetic radiation different from that in the first operating state.The random structure of the second identification element, formed either from pigments or particles of the at least one dye, preferably represents a second machine-readable piece of information. If the random structure of the second identification element, formed either from pigments of a colorant or from particles of the at least one dye, represents a second machine-readable piece of information, this information is preferably determined by a processing unit, e.g., by grayscale determination or other threshold evaluation, with respect to the number and / or intensity of the pigments or particles in question, or with respect to the area they fill or occupy in the first identification element. The respective information content of the first and / or second identification element is preferably omnidirectionally readable.

[0092] As the Fig. As shown in Figure 2, the second identification element is designed as a random structure formed from pigments 03 or the at least one dye. This random structure of the second identification element, formed from pigments 03 or the at least one dye, is only perceptible to an observer in the visual range and photographically recognizable due to an optical change triggered by irradiation with electromagnetic energy of a wavelength, for example, from the UV range. The optical perception of the second identification element therefore requires excitation, which occurs in the form of an energy input. This energy is electromagnetic in nature and preferably originates from radiation whose respective wavelength lies, for example, in the UV range.In principle, the emission spectrum of the radiation emitted into the surface containing the identification elements in the second operating state of the identification feature 01 includes the wavelength of at least one absorption line of the pigments or the particles of the at least one dye of the second identification element, wherein the radiation energy absorbed by the respective pigment or dye particles causes the respective pigment or dye particles to emit electromagnetic radiation in the visible light spectrum. In a preferred embodiment, the radiation energy of the electromagnetic radiation emitted into the surface containing the identification elements in the second operating state of the identification feature 01 is at least 1.59 eV.

[0093] The pigments 03 or the particles of the at least one dye of the second identification element are preferably contained in a printing ink or ink used for the printing production of the first identification element, i.e., for printing, for example, the QR code, wherein at least a subset of the pixels 02 of the pixel pattern forming the first identification element are formed from this printing ink or ink. The first identification element and the second identification element are each arranged on or applied to the object, i.e., to its surface, e.g., in a printing-plate-bound printing process, preferably in an offset printing process, a gravure printing process, or a letterpress printing process, or in a printing-plate-free, i.e., direct, printing process, e.g., in an inkjet printing process or an aerosol jet printing process.The object on whose surface the identification feature 01 is formed is, for example, a substrate on which several identification features 01 are formed in a printing process, e.g., in a single unit, using a printing press. The substrate is, for example, a web of material or a printed sheet, and may consist of, for example, paper, plastic film, metal foil, or textile. In another embodiment, the identification feature 01 is formed directly and immediately on the surface of the object using a printing process, and the object may be, for example, packaging, in particular a hollow body, e.g., a (glass) bottle, a (tin) can, or a plastic container, or a product suitable for sale as such, e.g., made of plastic, ceramic, metal, or wood.In the case of multiple identification features 01 applied to the substrate, these are separated after printing. The respective individual identification features 01, each designed as a label, are then available to be applied to another object or product whose identity and / or authenticity is to be verified at a later time using the relevant identification feature. The second identification element, designed as a random structure formed from pigments 03 or at least one dye, can be the same or different, i.e., individually designed, for each of the multiple identification features 01 printed on the substrate in the same production process, just like the respective first identification element belonging to the same identification feature 01.

[0094] In a preferred embodiment, the pigments 03 contained in the printing ink or ink, used to form the random structure, have a core with a carrier substance and with either a fluorescent material or a phosphorescent material, the core preferably having a substantially spherical shape. A shell surrounding the core is provided, the shell containing photochromic material with which radiation emitted by the fluorescent or phosphorescent material is attenuated or at least attenuated. The pigments 03 used to form the random structure then correspond, for example, to the embodiment described in WO 2007 / 005354 A2.

[0095] Building on the above description, a method is proposed in which an identification feature with several identification elements arranged within a defined area on or within the object is used to identify the object and / or to verify its authenticity, wherein in a first operating state of the identification feature, by irradiating the area containing the identification elements with visible light, a first identification element becomes visually recognizable and a second identification element does not become visually recognizable, wherein the second identification element is formed as an integral part of the first identification element as a random structure formed from pigments or from particles of at least one dye.In a second operating state of the identification feature, the pigments or particles of the at least one dye forming the random structure of the second identification element are excited to spontaneous emission and fluorescence or phosphorescence by irradiating the surface containing the identification elements with electromagnetic radiation different from that in the first operating state, thus becoming visually detectable. At a first location, e.g., at the production site of the identification feature in question, a single first image or a sequence of first images of the identification feature is captured by a first data acquisition device in a first illumination situation in which the random structure of the second identification element is visually detectable.wherein the respective captured first image in the form of digitized image data or a first piece of information decoded from the respective captured first image is stored in a first memory, wherein at a second location, different from the first, a single second image or a sequence of second images preferably identical or at least comparable with regard to the lighting conditions is captured from the same identification feature using a second data acquisition device in a lighting situation in which the random structure of the second identification element is visually recognizable, wherein the respective captured second image in the form of digitized image data or a second piece of information decoded from the respective captured second image is stored in a second memory,The first and second storage devices are connected via a communication link after a data exchange request originating at the second location. Following data transmission, the image data and / or decoded information of the first image of the identification feature affixed to or on the object, stored in the first storage device, and the image data and / or decoded information of the second image of the same identification feature affixed to or on the object are compared using a processing unit. The identity and / or authenticity of the object is verified based on this comparison. The respective sequences consist, for example, of three or more images, which are captured under various lighting conditions.wherein a first image is acquired, e.g., under normal daylight conditions with light in the wavelength range of 380 nm to 790 nm, a second image is acquired during irradiation of the identification feature with radiation from the IR or UV range, and a third image is acquired after the irradiation of the identification feature with the IR or UV range has ended. The respective sequences for the first image and for the second image preferably each contain the same number of images.

[0096] The first, preferably contactless, digital data acquisition device and the second, preferably contactless, digital data acquisition device are, for example, each configured as a scanner or as a camera, in particular as a digital camera. The acquisition of the first image and / or the acquisition of the second image is carried out, for example, using a code reader configured as an application program, such as a QR code reader or a program for automated text recognition or optical character recognition. The first storage device and / or the second storage device are, for example, each configured as a database in which the respective image is stored in the form of digitized image data and / or information decoded from the acquired image is stored digitally.

[0097] The respective imaging and / or decoding takes place before the item is delivered to a user, for example, by a supplier (who may also be the manufacturer of the item in question). This occurs, for example, during the manufacturing of the item or during the application of the identification feature 01 to or on the item or product. At a later time, the user captures the second image of the identification feature 01 by irradiating the second identification element with electromagnetic energy of a wavelength, for example, from the UV range. The image data of the second image and / or its decoded information are stored, at least temporarily.To identify the object bearing the identification mark 01 and / or to verify the authenticity of this object, the image data of the respective stored first image of the identification mark 01 affixed to the object and the image data of the respective captured second image of the identification mark 01 affixed to this object are then preferably compared in a processing unit, e.g., using image processing or pattern recognition methods, and checked for consistency. Alternatively or additionally, the first piece of information decoded from the respective captured first image and the second piece of information decoded from the respective captured second image are preferably compared in the processing unit and checked for consistency.

[0098] If there is a given, insufficient, and / or no match between the stored first image of the identification feature 01 affixed to or on the object and the captured second image of the identification feature 01 affixed to or on this object, the processing unit performing the comparison generates a message regarding the comparison result to the user and / or the supplier or manufacturer of this object and / or outputs it, e.g., visually on a display device or audibly. The comparison of the stored first image of the identification feature 01 affixed to the object with the captured second image of the identification feature 01 affixed to this object, i.e.,The previously described comparison of their respective digitally available image data or decoded information is carried out in a preferably mobile communication device, e.g., a smartphone, which nowadays usually has a sufficiently powerful computing unit.

[0099] In another embodiment, the second image of the identification feature 01, which is located on or attached to the object in question, is transmitted by the second data acquisition device via a preferably wireless communication connection, e.g., via the internet or a mobile network connection, to a stationary computer, e.g., a network server, operated by or for the supplier or manufacturer of the object. The transmission of the image data or the decoded information, in particular of the second image of the identification feature 01, located on or attached to this object, e.g., to the stationary computer, and / or the transmission of the message relating to the comparison result, e.g., from the stationary computer, in particular to the user and / or to the supplier or manufacturer of the object in question, and / or the transmission of the message relating to the comparison result, e.g.,The communication from the user, in particular to the stationary computer and / or to the supplier or manufacturer of the item in question, is preferably encrypted.

[0100] In a particularly preferred embodiment of the invention, in a set of identification features 01 printed, for example, in the same production process, the respective first identification elements of all identification features 01 belonging to this set are identical, i.e., they are all encoded with the same information, whereas the respective second identification element belonging to a specific identification feature 01 is different from the other second identification elements belonging to this set. This means that in a specific, e.g.,In a single production process, particularly with a printing press, a quantity of identification features 01 are produced. These identification features 01 differ from one another only by their random structure, each formed from pigments or at least one dye, which constitutes the second identification element in each identification feature 01. However, precisely because of this difference, they are also uniquely identifiable. The random structure in question is produced, for example, by adding fluorescent pigments or other luminescent, or at least reflective or polarizing particles to the printing ink or ink and by a stochastic distribution of these pigments or particles in the printing ink or ink, wherein the pigments or particles in question are small in relation to the area of ​​the respective pixels, e.g., of the pixel pattern of the first identification element.In an alternative implementation variant, in a set of identification features 01 printed, for example, in the same production process, not only the respective second identification elements, but also at least a subset of the respective first identification elements can be individually designed, in that in the relevant subset the relevant first identification elements or all first identification elements of this set of identification features 01 are each encoded with information that differs from other identification features 01 of this set.

[0101] It may be provided that, for example, at the end of a production line for the production of a specific quantity of identification features 01, at least one first image of each completed identification feature 01 is continuously captured in the production machine in question, e.g., a printing press, in accordance with the production progress for the production of this quantity of identification features 01, using a non-contact digital data acquisition device, e.g., a scanner or a camera, and stored, e.g., in the form of digital image data, in a first storage medium, in particular a database, wherein this at least one first image of the identification feature 01 in question depicts either only its first identification element or its first identification element together with its second identification element.To create the image of the relevant identification feature 01 in the production machine or processing machine in question, e.g., a printing press, a lighting device with at least one light source made of a semiconductor material, e.g., an LED or laser lighting device, and / or a scanner or a semiconductor camera with a CCD image sensor or a CMOS image sensor is used. Alternatively, a lighting device with at least one gas discharge tube can be used, e.g., a xenon-filled flash tube. The production machine or processing machine can also be configured as a packaging machine, a filling machine, or a finishing machine. The first image is preferably captured without the use of a polarizing filter, a color filter, or any other additional device that manipulates the light emitted by the relevant identification feature 01.

[0102] In the first illumination situation at the first location and in the second illumination situation at the second location, electromagnetic radiation is used which is at least partially absorbed by the pigments or particles of the at least one dye of the random structure. The electromagnetic radiation-absorbing pigments or particles of the at least one dye of the random structure are excited by the at least partial absorption of the electromagnetic radiation to at least a visually detectable luminescence, preferably also to fluorescence or phosphorescence, wherein the first image and the second image are each captured by the respective data acquisition device during the luminescence of the pigments or particles of the at least one dye of the random structure.

[0103] It is advantageous to form identification features 01 of the type described above using a printing process with a printing press, for example, a sheet-fed printing press or a web-fed printing press. This printing press preferably has at least one printing unit operating in an inkjet printing process, wherein this printing unit forms the identification feature 01 by applying printing ink or ink containing either the pigments 03 or the particles of at least one dye of the second identification element to the surface of the object in question. This printing press has a control unit that controls the printing process carried out by the printing press and preferably several drives and / or actuating elements, wherein the drives and / or actuating elements are controlled by the control unit, for example, depending on factors particularly relevant to this printing press.The control unit and, for example, the drives and / or actuators it controls are preferably interconnected, at least data-wise, in a network, particularly a digital one, such as a bus system. The drives and / or actuators are controlled by the control unit through data communication via the network, particularly depending on parameters detected by sensors in this printing press or specified by a program. It is advantageous to also connect the printing unit generating the relevant identification feature 01 to this network and to communicate data relating to the respective identification feature 01 via this network, for example, controlled by the control unit. Preferably, a network-connected component, such as a bus system, is installed in the printing press.A data acquisition device designed as a camera is arranged, wherein this data acquisition device captures at least one image of the identification feature 01, and wherein the at least one captured image, in the form of digitized image data or information decoded from the at least one captured image, is stored in a memory preferably connected to the network. The image data stored in the memory or the decoded information stored therein is preferably communicated via the network only after a request triggered outside the printing press.

[0104] In an advantageous embodiment, the data acquisition device arranged in the printing press captures a sequence of several images of the respective identification feature 01 within a defined period, wherein at least some of these images are captured under different lighting conditions, and the images belonging to the same sequence and captured under different lighting conditions are each stored in the memory. It is particularly advantageous to capture at least three images of each identification feature 01, which is preferably printed by the printing device using an inkjet printing process, with the data acquisition device arranged in the printing press. A first image depicts only the first identification element, which is, for example, designed as a QR code, because in the first lighting condition the second identification element, which has a random structure, is, for example, not visible.Under normal daylight conditions, i.e., with incident light in the wavelength range between 380 nm and 790 nm, it is not visually perceptible or recognizable. In the second illumination situation, a second image of the same identification feature 01 or the same identification features 01 is captured by the data acquisition device arranged in the printing press. In this second illumination situation, the respective identification features 01 are each irradiated with electromagnetic energy of a specific wavelength, so that the second identification element exhibiting the random structure is recognizable in the visual range together with the first identification element and can be captured by the data acquisition device, in particular imaged by a camera. The required electromagnetic energy is provided, for example, by a flash unit.In the third illumination situation, the irradiation of the respective identification features 01 with electromagnetic energy of a specific wavelength to make the second identification element exhibiting the random structure visible is terminated, and a third image is captured by the data acquisition device arranged in the printing press from the same identification feature 01 or from the same identification features 01, whereby the second identification element exhibiting the random structure is now recognizable due to spontaneous emission, fluorescence or - if the process is delayed in time and / or lasts significantly longer - phosphorescence, particularly in the visual range, and can be captured by the data acquisition device.This sequence of at least three images, each captured by the same identification feature 01 or features 01 with the data acquisition device arranged in the printing press, can be evaluated by the control unit, for example, to determine whether the respective identification feature 01 or features 01 were correctly created, i.e., printed, with the function of a security feature. This allows for testing, production control, or quality control of the respective identification features 01 to be performed within the printing press. The result of this testing, production control, or quality control, or the respective sequence of images of the same identification feature 01, is stored, for example, in the memory, preferably connected to the network.

[0105] As described above, a method for production control of identification features printed on a substrate or object using a printing press is feasible, wherein the identification features 01 comprise a first identification element that is visually detectable under daylight conditions and a second identification element that is not visually detectable under daylight conditions, wherein the second identification element only becomes visually detectable by irradiating the identification feature 01 with electromagnetic energy of a specific wavelength, such that this irradiated energy is at least partially absorbed by pigments of a colorant or particles of a dye in the second identification element, and these pigments or these particles of the dye are excited to a visually detectable spontaneous emission and fluorescence or phosphorescence, wherein the printing press is equipped with a device arranged within itThe data acquisition device captures a sequence of at least three images from each of the identification features 01 printed by a printing device of this printing press, wherein the first image of the identification feature 01 belonging to the respective sequence depicts only the first identification element that is visually detectable under daylight conditions, wherein the second image of the identification feature 01 belonging to the respective sequence depicts the first identification element together with the second identification element that spontaneously emits light upon irradiation with electromagnetic energy of a specific wavelength, wherein the third image of the identification feature 01 belonging to the respective sequence depicts the first identification element together with the second identification element that fluorescently or phosphorescently emits light after irradiation with electromagnetic energy of a specific wavelength has ceased, wherein theThe sequence of at least three images is evaluated by a control unit to determine whether the relevant identification feature 01 possesses the second identification element, which is not visually detectable under daylight conditions, emits spontaneously upon irradiation with electromagnetic energy of a specific wavelength, and fluorescently or phosphorescently after this irradiation ceases. Preferably, the printing unit of the printing press prints the respective identification features 01, each of which is, for example, designed as a QR code, using an inkjet printing process. The second identification element is, in particular, designed as a random structure contained within the first identification element. The pigments of the colorant or particles of the dye used for the second identification element are advantageously mixed by a stirrer and / or in an ultrasonic water bath and / or by means of an ultrasonic atomizer.The pigments of the colorant or particles of the dye used for the second identification element are incorporated into the printing ink or ink used for printing the first identification element. The pigments of the colorant or particles of the dye used for the second identification element are generally incorporated in a mass fraction of less than 5%, in particular up to a maximum of 2%, into the printing ink or ink used for printing the first identification element. For the second identification element, pigments of the colorant or particles of the dye are used, in particular, which each have a core with a fluorescent material or with a phosphorescent material and each have a shell surrounding the core made of a photochromic and / or a fluorescent or a phosphorescent material. The pigments correspond, for example, to the embodiment described in WO 2007 / 005354 A2. The shell, i.e., the surface of the pigments, consists, for example, of a chitosan algnate or of aCellulose, or ethylcellulose, or gelatin, or gum arabic, or melamine-aldehyde resin, or melamine-formaldehyde resin, or melamine-urea-formaldehyde resin, or nylon, or phenol-formaldehyde, or polyacrylonitrile, or polyamide, or a polyelectrolyte complex, or polyethylene, or polyethylene glycol, or poly-L-lysine, or polylactide, or polylysine, or alginate, or polynucleotide, or polypeptide, or polyphosphazene, or polypropylene, or polysaccharide, or polystyrene, or urea-formaldehyde resin. The electromagnetic energy of a specific wavelength required for the spontaneous emission of the second identification element is preferably emitted by a flash unit, e.g., controlled by the control unit.

[0106] The pigments of the colorant or particles of the dye used for the second identification element preferably have a linear extent in the range between 0.5 µm and 10 µm. The pigments of the colorant or particles of the dye used for the printing ink or the ink of the first identification element are each dispersed in a first dispersing agent, i.e.,The pigments of the colorant or the particles of the dye, in combination with the first dispersing agent, each form a first heterogeneous mixture, and the pigments of the colorant or particles of the dye used for the second identification element are each dispersed in a second dispersing agent to form a second heterogeneous mixture, wherein the first dispersing agent and the second dispersing agent preferably differ from each other, so that different dispersing agents are used for the first identification element and for the second identification element, wherein there is preferably repulsion, i.e., a repulsion, between these two dispersing agents.The use of different dispersing agents for the first identification element and for the second identification element promotes coagulation of the pigments of the colorant or particles of the dye used for the second identification element, i.e., an agglomeration of these pigments of the colorant or particles of the dye and thus a disruption of their finely dispersed state in the printed image produced by the printing device.

[0107] To improve the printability of the printing ink or ink used in an inkjet printing process, this printing ink or ink has a conductivity at 23°C preferably in the range of 900 µS / cm to 2,200 µS / cm, particularly between 1,000 µS / cm and 1,900 µS / cm. The conductivity of the printing ink or ink used is increased, for example, by the addition of additives, preferably salts and / or polymers, e.g., polymer salts. The additives can be added to the printing ink or ink used in the form of, for example, a solid and / or a solution and / or a dispersion. Alternatively or additionally, the printing ink or ink contains at least one conducting salt, e.g., from the group of alkali metal salts or ammonium salts, wherein the conducting salt is, for example,The ink is formed as ammonium sulfate, ammonium chloride, ammonium bromide, magnesium sulfate, sodium and potassium sulfate, sodium and potassium chloride, tetra-n-butylammonium bromide, tetra-n-butylammonium tetrafluoroborate, tetra-n-butylammonium hexafluorophosphate, or lithium hexafluorophosphate. The viscosity of this printing ink at 25°C is, for example, 2.5 mPa s to 6 mPa s for a CIJ printing process (CIJ = continuous ink jet) or, for example, 3 cPa s to 8 cPa s for a piezoelectric printing process. The density of the pigments or dye particles used in the printing ink is in the range of 0.6 kg / m³. 3 and 1.3 kg / m² 3 , preferably between 0.8 kg / m² 3 and 1.0 kg / m² 3 When using water-based printing ink or paint, the upper values ​​of the specified ranges are preferred.

[0108] This results, for example, in an identification feature with at least two identification elements arranged in a defined, limited area for the identification of an object, wherein, by irradiation of the area containing the identification elements of the identification feature with visible light, its first identification element is visually recognizable and its second identification element is not visually recognizable, wherein the first identification element is formed from a printing ink or from an ink, wherein the second identification element is formed as a random structure formed from pigments of a colorant or as a random structure formed from particles of at least one dye, wherein the random structure of the second identification element is formed as an integral part of the printing ink or the ink of the first identification element.The printing ink or ink has a conductivity of 900 µS / cm to 2,200 µS / cm at 23°C and / or contains at least one polymer as an additive and / or at least one alkali metal salt or an ammonium salt as a conducting salt. A conducting salt is a salt that transports electrical charges during electrolysis and / or reduces the ohmic resistance of a solution. The pigments or particles of the at least one dye that form the random structure of the second identification element have a density, for example, in the range of 0.6 kg / m³. 3 and 1.3 kg / m² 3The viscosity of the printing ink or the ink at 25°C is, for example, in the range between 2.5 mPa s and 6 mPa s or in the range between 3 cPa s and 8 cPa s. In a preferred embodiment, the pigments or particles of the at least one dye forming the random structure of the second identification element have a spherical surface, and those pigments of a colorant or those particles of at least one dye that are contained as a coloring agent in the printing ink or ink forming the first identification element are angular or spherical.Furthermore, the pigments of the colorant or the particles of the dye in the printing ink or the printing ink of the first identification element are each dispersed in a first dispersing agent, and the pigments of the colorant or the particles of the dye in the second identification element are each dispersed in a second dispersing agent, wherein the first dispersing agent and the second dispersing agent preferably differ from each other in composition. The pigments of the colorant or the particles of the at least one dye forming the random structure of the second identification element preferably have a surface that diffusely reflects incident light. The pigments of the colorant or the particles of the at least one dye forming the random structure of the second identification element, for example, have a linear extent in the range between 0.5 µm and 10 µm.The printing ink or the ink of the first identification element is preferably applied to a surface of the object to be identified in a layer thickness in the range of 0.3 µm to 10 µm. The pigments of the colorant or the particles of the dye, in each case of the printing ink or the ink of the first identification element, are formed from an organic, inorganic, or synthetic crystalline powder, or in particular from carbon black, titanium(IV) oxide, aluminum bronze, or brass bronze. The pigments of the colorant or the particles of the dye, in each case of the printing ink or the ink of the first identification element, are present in a mass fraction, e.g.,between 12% and 18% in the printing ink or ink in question and / or the pigments of the colorant forming the random structure of the second identification element or the particles of the dye are each contained in a mass fraction, in particular of less than 5%, preferably of less than 2%, in the printing ink or ink in question of the first identification element.

[0109] An identification feature is also obtained with at least two identification elements arranged in a defined, limited area for the identification of an object, wherein, by irradiation of the area containing the identification elements of the identification feature with visible light, its first identification element is visually recognizable and its second identification element is not visually recognizable, wherein the first identification element is formed from a printing ink or from an ink, wherein the second identification element is formed as a random structure formed from pigments of a colorant or as a random structure formed from particles of at least one dye, wherein the random structure of the second identification element is formed as an integral part of the printing ink or the ink of the first identification element.wherein the printing ink or ink of the first identification element, applied to a surface of the object to be identified in a grid-like arrangement of pixels, has a layer thickness in the range of 0.3 µm to 10 µm, wherein the pigments of the colorant or the particles of the at least one dye forming the random structure of the second identification element form a planar structure encompassing several adjacent pixels of the graphic, in particular raster graphics, by coagulation, i.e. by clumping together ( Fig. 3) The raster graphic consists of a grid-like arrangement of pixels, this arrangement forming an image in the form of computer-readable data. This arrangement has at least two groups of pixels between which there is a visually perceptible contrast. The pigments of the colorant or the particles of the at least one dye, which form the random structure of the second identification element, form a planar structure encompassing several adjacent pixels of the raster graphic through coagulation ( Fig. 3) are each formed in pixels of the same brightness, e.g., in the pixels formed with a printing ink or ink that is darker compared to other pixels of the same raster graphic. The pigments of the colorant or the particles of the at least one dye forming the random structure of the second identification element have a length in the range between 0.5 µm and 10 µm. Advantageously, the pigments of the colorant or the particles of the at least one dye forming the random structure of the second identification element exhibit spontaneous emission of visually perceptible light and / or fluorescence and / or phosphorescence upon incident electromagnetic radiation of the type described above. Furthermore, the identification feature can be formed with any of the previously described physical and / or material characteristics.

[0110] Accordingly, an object can be formed with an identification feature arranged for its identification, wherein the identification feature has at least two identification elements in a defined, limited area, wherein the first identification element is formed from a printing ink or an ink, wherein the second identification element is formed as a random structure formed from pigments of a colorant or as a random structure formed from particles of at least one dye, wherein the random structure of the second identification element is formed as an integral part of the printing ink or the ink of the first identification element, wherein the printing ink or the ink of the first identification element is applied to a surface of the object to be identified in a layer thickness in the range of 0.3 µm to 10 µm, wherein the random structure of the second identification elementThe pigments forming the colorant or the particles of the at least one dye must have a surface that diffusely reflects incident electromagnetic radiation. This object is, for example, designed as a printing material made of paper, plastic film, metal foil, or textile, or as a hollow body, bottle, can, or product made of plastic, ceramic, metal, or wood. The pigments of the colorant or the particles of the dye, each from the printing ink or the ink of the first identification element, must be made of an organic, inorganic, or synthetic crystalline powder, or of carbon black, or of titanium(IV) oxide, or of aluminum bronze, or of brass bronze, and / or the pigments of the colorant forming the random structure of the second identification element, or the particles of the at least oneThe dyes have a surface made of a chitosan algnate, cellulose, ethylcellulose, gelatin, gum arabic, melamine aldehyde resin, melamine formaldehyde resin, melamine urea formaldehyde resin, nylon, phenol formaldehyde, polyacrylonitrile, polyamide, a polyelectrolyte complex, polyethylene, polyethylene glycol, poly-L-lysine, polylactide, polylysine, alginate, polynucleotide, polypeptide, polyphosphazene, polypropylene, polysaccharide, polystyrene, or urea formaldehyde resin. It may be provided that by irradiating the surface containing the identification elements of the identification feature with visible light in a wavelength range of 380 nm to 790 nm, itsThe first identification element is visually recognizable, and the second identification element is not visually recognizable.

[0111] Alternatively, an object with an identification feature arranged for its identification is also obtained, wherein the identification feature has at least two identification elements in a defined bounded area, wherein the first identification element is formed from a printing ink or an ink, wherein the second identification element is formed as a random structure formed from pigments of a colorant or as a random structure formed from particles of at least one dye, wherein the random structure of the second identification element is formed as an integral part of the printing ink or the ink of the first identification element, wherein the printing ink or ink of the first identification element applied to a surface of the object to be identified is preferably applied in a raster graphic consisting of a grid-like arrangement of pixels.wherein the pigments of the colorant forming the random structure of the second identification element or the particles of the at least one dye form a planar structure encompassing several adjacent pixels of the raster graphic by coagulation (, Fig.3) The pigments of the colorant or the particles of the at least one dye forming the random structure of the second identification element exhibit, for example, spontaneous emission of visually perceptible light and / or fluorescence and / or phosphorescence when exposed to incident electromagnetic radiation of a specific wavelength, wherein the pigments of the colorant or the particles of the at least one dye forming the random structure of the second identification element exhibit their spontaneous emission of visually perceptible light and / or fluorescence and / or phosphorescence when exposed to incident electromagnetic radiation with a wavelength particularly from the IR or UV range. Furthermore, the identification feature of the object may be formed by one or more of the previously described physical and / or material characteristics.

[0112] A method for verifying the identity and / or authenticity of an object is also derived, in which an identification feature with a random structure formed from pigments of a colorant or from particles of at least one dye is used, wherein the random structure is formed as an integral part of a printing ink or ink applied to a surface of the object, wherein the pigments of the colorant or the particles of the at least one dye forming the random structure are excited to spontaneous emission and fluorescence or phosphorescence by irradiation of the identification feature with electromagnetic radiation from the IR or UV range and are visually detectable, wherein, for the purpose of verifying the identity and / or authenticity of the object, a data acquisition device is used to record the identification feature during irradiation of the identification feature with the electromagnetic radiation.a single first image or a sequence of first images is captured from the IR or UV range, and a single second image or a sequence of second images is captured from the identification feature in question using the same data acquisition device after the identification feature has been irradiated with electromagnetic radiation from the IR or UV range. A comparison of the respective first and second images is performed by a processing unit to determine whether the pigments of the colorant forming the random structure or the particles of the at least one dye fluoresce or phosphoresce. If the processing unit detects fluorescence or phosphorescence of the pigments of the colorant forming the random structure or of the particles of the at least one dye, the identity and / or authenticity of the object is considered confirmed. The random structure is, for example,The identification feature is not visually detectable by irradiation with light in a wavelength range of 380 nm to 790 nm. The identification feature is applied to or onto the object using a printing process that is either fixed to a printing plate or a printing plate-free process. The object can be, for example, a substrate in the form of a web or sheet, packaging, a hollow body, a bottle, a can, or a plastic container. The identification feature is preferably applied to or onto the object in a printing press, a packaging machine, a filling machine, or a converting machine. The respective images of the identification feature are captured, in particular, by a data acquisition device of a mobile communication device, preferably a camera of a mobile phone or a smartphone.The pigments of the colorant forming the random structure, or the particles of the at least one dye, form a planar structure through coagulation, the planar structure being larger than the optical resolution of the data acquisition device used for the images. The information content of the random structure is determined, in particular by a processing unit, through grayscale determination or threshold evaluation with regard to the number and / or intensity of the pigments or particles in question, or with regard to the area they occupy. The identifying feature of the object can, in turn, be formed by one or more of the previously described physical and / or material characteristics. Reference symbol list 01 Identification feature 02 pixels 03 Pigment

Claims

[1] An object having an identification feature 01 arranged for its identification, wherein the identification feature 01 has at least two identification elements in a defined, limited area, wherein the first identification element is formed from a printing ink or an ink, wherein the second identification element is formed as a random structure formed from pigments 03 of a colorant or as a random structure formed from particles of at least one dye, wherein the random structure of the second identification element is formed as an integral component of the printing ink or the ink of the first identification element, wherein the printing ink or ink of the first identification element applied to a surface of the object to be identified is applied in a grid-like arrangement of pixels 02, characterized bythat the pigments 03 of the colorant forming the random structure of the second identification element or the particles of the at least one dye form a planar structure comprising a plurality of adjacent pixels 02 of the grid-shaped arrangement by coagulation, wherein the grid-shaped arrangement has at least two types of pixels 02 between which there is a visually perceptible contrast, wherein the pigments 03 of the colorant forming the random structure of the second identification element or the particles of the at least one dye, which form a planar structure comprising a plurality of adjacent pixels 02 of the grid-shaped arrangement by coagulation, are each formed in pixels 02 of the same brightness. [2] Article according to claim 1, characterized bythat this object is designed as a printing material made of paper or of a plastic film or of a metal foil or of a textile or as a hollow body or as a bottle or as a can or as a product made of a plastic or of a ceramic or of a metal or of wood. [3] Article according to claim 1 or 2, characterized by that the pigments 03 of the colorant forming the random structure of the second identification element or the particles of the at least one dye have a surface that diffusely reflects incident electromagnetic radiation. [4] Article according to claim 1 or 2 or 3, characterized bythat the pigments 03 of the colorant forming the random structure of the second identification element or the particles of the at least one dye exhibit a spontaneous emission of visually recognizable light and / or fluorescence and / or phosphorescence due to incident electromagnetic radiation. [5] Article according to claim 4, characterized by that the pigments 03 of the colorant forming the random structure of the second identification element or the particles of the at least one dye exhibit their spontaneous emission of visually recognizable light and / or fluorescence and / or phosphorescence by incident electromagnetic radiation with a wavelength from the IR range or from the UV range. [6] Article according to claim 1 or 2 or 3 or 4 or 5, characterized bythat by irradiating the area having the identification elements of the identification feature 01 with light in a wavelength range from 380 nm to 790 nm, its first identification element is visually recognizable and its second identification element is not visually recognizable. [7] Article according to claim 1 or 2 or 3 or 4 or 5 or 6, characterized by that the grid-like arrangement of pixels 02 forms an image in the form of computer-readable data. [8] Article according to claim 1 or 2 or 3 or 4 or 5 or 6 or 7, characterized by that the grid-like arrangement of the pixels 02 is designed as a QR code.

Images