WO2015086709A2

WO2015086709A2 - Security element and verification method having an excitation-dependent optical effect in the non-visible wavelength region

Info

Publication number: WO2015086709A2
Application number: PCT/EP2014/077286
Authority: WO
Inventors: Stefan TRÖLENBERG; Jörg Fischer
Original assignee: Bundesdruckerei Gmbh
Priority date: 2013-12-10
Filing date: 2014-12-10
Publication date: 2015-06-18
Also published as: EP3079918A2; DE102013225514A1; EP3079918B1; WO2015086709A3

Abstract

The invention relates to a security element (110), comprising a substrate layer and a security structure (115) formed on the substrate layer, which is constructed having a structural color (210) comprising microcapsules (10) containing colloidal particles (13), which by means of a structural excitation comprising the creation of an electrical and/or magnetic field can be arranged and/or re-arranged in a crystal-like structure to each other. The crystal-like structure (15) has reflection and/or transmission properties for light that can be influenced and/or adjusted by way of the structural excitation. In a non-excited state, the microcapsules (10) have an increased transmission capability and reduced reflection ability for at least one wavelength in the non-visible wavelength region. In the structural excited state, in which an electrical and/or magnetic field generated by way of structural excitation exists in the region of the microcapsules (10), the microcapsules (10) have a reduced transmission capability and an increased reflection ability compared to the non-structural excited state. The invention further relates to a verification method.

Description

Security element and verification method with an excitation-dependent optical effect in the invisible wavelength range

The invention relates generally to a security element with an excitation-dependent optical effect in the non-visible wavelength range, wherein the

Excitation is not irradiation of light, as well as a method for verifying such a security element.

A variety of security and value documents with security features and security elements are known from the prior art, which show an optical effect when interacting with light in the non-visible wavelength range. Thus, optical elements in the form of holograms are known which have a diffraction only with light in the non-visible wavelength range, for example the IR wavelength range. Other security elements show a wavelength dependent

Transmission or reflection.

From DE 10 2008 020 769 B3 an electrically stimulable security element is known. The proposed security element comprises a recording material in which at least one volume hologram is stored, and at least two separately formed electrodes, to which a voltage can be applied and / or which can be charged, wherein the at least two electrodes and the recording material are formed and mutually are arranged, that when applying the voltage and / or an application of charges at least one local mechanical change, in particular deformation of the

Recording material occurs, so that a reconstruction of the volume hologram is at least locally changed, wherein at least one elastic element between the recording material and one of the at least two electrodes is arranged. The document thus shows an electrically stimulable volume hologram. An electrical voltage can influence an optical effect. In a verification, for example, an occurrence of a disturbance of the reconstruction of the hologram is checked depending on the applied voltage.

Printing inks are known from EP 2 463 11 1, the color impression of which is brought about via microparticles contained in one color, which are aligned with one another and arranged in a crystal structure. There are printing inks described in a Pressure medium having a plurality of particles which are dispersed in the medium and have electrical or magnetic properties, so that they align with each other in a crystal structure when using an electric or magnetic field. This crystal structure ensures that light of a particular

Wavelength can propagate only along certain directions or not at all in the crystal structure and is reflected accordingly. This causes a color impression due to the wavelength-selectively reflected light. In contrast to a body color can be spoken of a structural color, since a geometric arrangement of the colloidal particles is responsible for the expression of the color. It is known to use such structural colors for the manufacture of objects whose color impression is easily changeable to a human observer.

It is a general endeavor to develop security documents in such a way that they contain security elements and features which are harder to imitate and / or manipulate for counterfeiters.

The invention is therefore based on the technical problem of a novel

To provide security element and a method with which the security element is easily verifiable.

The invention is achieved by a security element having the features of patent claim 1 and a verification method having the features of patent claim 4.

Further advantageous embodiments will become apparent from the dependent claims.

The invention is based on the idea of further developing the structural colors known from the prior art, which have an optical effect similar to that of a photonic crystal, and to provide security elements therewith, in particular for value or security documents. In particular, the properties of the colloidal particles are adjusted so that the optical interaction in the

structure-stimulated state of the structure color with light in the non-visible

Wavelength range occurs. In particular, a size of the colloidal nanoparticles is adjusted, so that when forming a suitable electrical or

magnetic field in the area of the printed structure color, a crystal lattice structure is produced, which interacts with light in the UV wavelength range or in the IR range. Wavelength range shows, however, its visible impression in the visible

Wavelength range not changed.

This gives a security element, which is detectable only with light in the non-visible wavelength range and is additionally dependent on an excitation with an electric or magnetic field. The effort, such

Making security element is significantly increased, so that a fake is difficult. The security element is machine-readable and not visually recognizable. Counterfeiters easily "overlook" such "hidden" security elements that are not immediately visible, so that counterfeiting is due to the absence of the corresponding security elements

Security elements and the absence of the associated effect in a verification, e.g. at a border crossing point, can be easily recognized.

Thus, a novel security element is created, which can be checked for its presence and its integrity by means of a novel verification procedure.

definition

Characteristics, which can be used for a verification and thus a

Hedge against unauthorized duplication or making, a

Falsifying or the like are called security features.

Entities having at least one security feature are called

Security element called. Thus, any physically trained object that includes at least one security feature is a security element.

Documents that have at least one security feature are called

Security documents called. Security documents include i.a. Badges, driving licenses, identity cards, but also banknotes, postage stamps, visas and fake labels and cigarettes, tickets or the like.

Value documents are security documents to which a value is assigned, e.g.

Banknotes, postage stamps etc. Pigments which show emission of light as a result of excitation, for example exposure to UV light, are referred to as luminescent pigments. The emission caused by the excitation is referred to as luminescence, the excitation as luminescence excitation.

A preparation that can be used to print information is also referred to as ink or ink.

A preparation whose color impression produced in the printed condition is caused by pigments absorbing certain wavelengths of light independently of environmental conditions and / or excitation and / or

remit / reflect are called body colors.

Printing preparations or inks or inks whose color impression in the printed state is caused by the fact that a plurality of particles in one

are arranged crystal-like regular structure, so that a light propagation of individual wavelengths through the crystal structure only in certain directions or not at all possible and this is a color impression is caused to be as

Structure colors designated.

A color of light is determined by a wavelength of light. Such a color is also called spectral color, as this is in the decomposition of a radiation which has light of a continuous wavelength spectrum in wavelength-selective

Components, this component one each for the selected wavelength

cause characteristic color impression. Although the visible wavelength range only covers the wavelength of about 380 nm to 780 nm, ie only wavelengths from this range cause a color impression in a human observer, it is assumed here that also light in the UV wavelength range with wavelengths less than 380 nm or in the IR Wavelength range with wavelengths greater than 780 nm has a color that corresponds to the respective wavelength.

The non-visible wavelength range includes UV light with wavelengths below 380 nm and IR light with wavelengths greater than 780 nm. The decisive factor is that light from these wavelengths is optically imperceptible to humans. Particularly preferred wavelength ranges of the invisible wavelength range include the wavelengths 190 nm to 380 nm and 780 nm to 1100 nm. The light of these preferred ranges can be easily detected with silicon-based semiconductor detectors. Thus, CMOS and CCD sensors can be used for the detection of non-visible light in the preferred wavelength ranges between 190 nm and 380 nm or 780 nm and 1100 nm.

As white light is here considered an electromagnetic broadband radiation with a continuous wavelength spectrum, which includes the infrared

Wavelength range and the UV wavelength range includes.

From the prior art, in particular EP 2 463 11 1 A2, printing preparations are known which are structural inks. There are described printing preparations comprising a plurality of nano- or microparticles having electrical or magnetic properties which are arranged in an electric or magnetic field relative to each other in a crystal-like regular structure. There it is described that the crystal-like structures can be photonic crystals. A photonic crystal is a regular periodic structure that promotes or suppresses light propagation for single or multiple wavelengths due to quantum mechanical effects. This creates a color impression of the corresponding photonic crystal.

Structural inks which have a changed color impression upon excitation are likewise described in EP 2 463 11 1 A2. These may be designed such that the printing preparation comprises microcapsules which are a substrate or medium

in which in turn a plurality of colloidal particles are arranged, which have an electrical or magnetic property and arrange in an electric or magnetic field relative to each other to a crystal or a crystal-like structure. There, it is described that the colloidal particles may be, for example, charged particles comprising, for example, aluminum, copper, silver, tin, titanium, tungsten, zirconium, zinc, silicon, iron, nickel, goblin or the like. The particles may further comprise a substance having a

Polymer material includes, for example, polystyrene (PS), polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polyethylene terephthalate (PET), etc. According to others Embodiments may charge uncharged particles with a charged material. For example, particles may be coated with metal inorganic oxides such as silicon oxide SiO _x , titanium oxide TiO _x , etc. But also with polymer materials

Coated particles coated with ion exchange resins and many more can be used. In EP 2 463 1 1 1 A2, a variety of exemplary

Versions described.

Field-free is a space in which neither an electric nor a

magnetic field are present. For the purposes of the objects described here, this is understood to mean the absence of an externally specifically set electric or magnetic field. A field caused by magnetic particles or electrically charged particles intrinsically present in an article is left unattended. Similarly, the magnetic field strength caused by the earth's magnetic field is considered to be insignificant, so that a space is field-free despite the existing geomagnetic field, if no additional magnetic field is present in the room. Upon application of voltage to electrodes to form a field in the article, this field is not considered intrinsic.

The orientation of the colloidal particles only by the electric field

brought about, the space is considered to be field-free when no electric field is present, even if, for example, a magnetic field is applied to affect a magnetorheological fluid in the room in terms of its viscosity.

The same applies to the case where a magnetic field is used to align the colloidal particles and an electric field is used to control the viscosity of an electrorheological fluid. The space is field-free if there is no "external" magnetic field with a field strength in the space that is greater than the field strength of the earth's magnetic field.

A field strength which causes a structure excitation is denoted by E _S A. An adjusted parenthetical expression (λ = A, _R ) or (λ = λυν) expresses that the

Structure excitation in the structure color causes an influence of light having the wavelength λ. For example, press

λυν) indicates that the structure excitation causes the structure color to influence light in the UV range. Ε _3Α (λ = A, _R ) indicates that the Structure excitation causes the structure color to influence light with a wavelength A, _R in the infrared wavelength range.

Printing inks or inks which, in the case of a luminescence excitation, in particular an irradiation of UV light, emit an emission of light, i. a

Luminescence, show, are referred to as luminescent.

As a time-resolved detection of a measured value or a quantity, the detection of this measured value or this variable becomes different successive ones

Time understood.

Preferred embodiments

The inventive security element with excitation-dependent alternating angle with light in the non-visible wavelength range comprises:

a substrate layer, and

a security structure formed on the substrate layer, which is formed with a structure color comprising microcapsules in which colloidal particles are arranged, which can be arranged in a crystal-like structure by means of a structure excitation, which comprises forming an electric and / or magnetic field, or / and umordenbar, wherein the crystal-like structure on the structure excitation influenceable and / or adjustable reflection and / or transmission properties has for light, the microcapsules in the non-structure excited state for at least one wavelength in the non-visible wavelength range increased transmittance and reduced reflectivity and the microcapsules in the structure-excited state, in which an electrical and / or a magnetic field generated via the structure excitation exist in the region of the microcapsules, in comparison to the non-structurally excited state a reduced one

Transmittance and have an increased reflectivity.

A method for verifying a security element, in particular a security element in a security document, wherein the security element comprises a security structure formed with a structure color, and wherein the

Structure color comprises microcapsules in which colloidal particles are contained, which by means of a structure excitation, which forming an electrical or / and magnetic field comprises, can be arranged to each other in a crystal-like structure and / or can be reorganized, wherein the crystal-like structure on the structure excitation influenceable and / or adjustable reflection and / or transmission properties for light, comprising the steps:

a) bringing about the structurally excited state of the security element by forming an electrical and / or magnetic field in the region of the security element,

b) irradiation of light with a wavelength that is in the non-visible

Wavelength range lies on the security element while the

Security element is in the structure-stimulated state, and

c) detecting an intensity of the light reflected at the security element of the one wavelength and / or an intensity of the transmitted by the security element light of the one wavelength, each during the

Security element is in the structure-stimulated state, and

d) comparing the detected reflected intensity in the structure-excited state with an expected reflection intensity and / or comparing the detected transmitted intensity in the structure-excited state with an expected transmission intensity of the one wavelength;

e) verifying the security element as true if the reflected intensity detected in the structure-excited state is greater than the expected reflection intensity and / or the transmitted intensity detected in the structure-excited state is smaller than the expected transmission intensity.

Thus created is a security element, which is especially for

Security documents and documents of value is appropriate, and a covert

Security feature in such a way that it is not recognizable without technical aids. As a rule, not even an existence of the security element is recognizable. Verification can be easily performed with a suitable light source emitting light in the non-visible wavelength region and a detection device which can detect light of the corresponding wavelength, and a detection device

Field generating device for the structure excitation done.

In the simplest embodiment, only the existence of an increased reflection of the invisible light radiation in reflection or a reduced transmission in the excited state of the security element is checked. An examination of the heightened Reflection or even occurring reflection of the non-visible light is preferred, since an increased absorption in the non-visible wavelength range can also occur for other reasons in a security element, so that for a lowered or low transmission of non-visible light and others

Causes may be present. As the expected reflection intensity, a small proportion of the irradiated light intensity can be selected, since reflection of light in the non-visible wavelength range on a physically formed security element or security document generally does not take place. For example, a value of 10% of the irradiated intensity can be assumed for the expected reflection. However, a value of 30%, 50% or even 80% can be set. This depends inter alia on the layer thickness of the security structure, i. the printed structure color amount per area and the concentration of the microcapsules in the structure color.

For the expected transmission intensity, a transmission value of 70% or 50% or even 30% can be set.

A much more reliable verification makes possible an embodiment in which additionally the non-structure-excited state of the security element is brought about, and while the security element is in the nonstructured state, light with the one wavelength is irradiated on the security element and while the security element in the not -structured state, the intensity of the light reflected at the security element of the one wavelength is detected and / or the intensity of the light transmitted through the security element of the one wavelength is detected,

and the reflected intensity detected in the non-pattern excited state is used as the expected reflection intensity and / or the transmitted intensity detected in the non-pattern excited state is used as the expected transmission intensity, and the security element is verified as genuine only when the reflected intensity detected in the structure-excited state is greater than the expected reflection intensity and / or the transmitted intensity detected in the structure-excited state is smaller than the expected transmission intensity. In such an embodiment, the effect of the pattern excitation on the interaction with the invisible light is clearly demonstrated. To bring about the non-excited state, a field clearance in one

Room area in which the security element is located. This can be done for example by interrupting a current flow through a coil or other inductance, which generates a magnetic field in the region of the security feature as a structure excitation. Otherwise, alternatively or additionally, a voltage may be set to zero to "remove" an electric field caused by one or two electrodes.

The induction of the structure-induced state, on the other hand, involves one

Embodiment generating a magnetic and / or electric field in the space area in which the security element is located. Electrodes may be disposed adjacent to the space such that upon application of a voltage, an electric field is generated in the security element and in the microcapsules. In some embodiments, the electrodes are already disposed and integrated in a security document adjacent to the security element. By applying a voltage to contacts connected to the electrodes, an electric field can then be generated reliably. A magnetic field can be generated via a coil structure. For example, spiral-shaped conductor structures can be formed in a security document surrounding the security element. A current can then be fed into the helical conductive structure via contacts guided on a surface of the security document, which generates a magnetic field.

However, the electrical and / or magnetic field can also be generated via external structures not coupled to the security element. The magnetic field, for example, by means of an approximation of a permanent magnet to the

Security element can be increased. By removing the permanent magnet, field freedom can be generated in the security element. Particularly preferred are magnets in mobile phones, as they generate strong magnetic fields for the comparatively compact design and are available everywhere and available.

In one embodiment, a wavelength in the UV wavelength range is selected as the one wavelength and irradiated upon irradiation of light of one wavelength UV light. In one embodiment of the security element, the structure color in the non-structure-excited state, the increased transmissivity and reduced reflectivity for at least one wavelength in the UV wavelength range and exists in the structure-excited state, the reduced transmissivity and the increased reflectivity for this at least one wavelength in the UV wavelength range.

Alternatively, in another embodiment, the one wavelength is selected in the IR wavelength range and radiated when irradiating light of one wavelength IR light. A security element is correspondingly designed in such a way that the structure color increases in the non-structure-excited state

Transmittance and the reduced reflectivity for at least one wavelength in the IR wavelength range and in the structure-excited state, the reduced transmissivity and the increased reflectivity for this at least one wavelength in the IR wavelength range exists.

In order to ensure that the detected detected light corresponds to the irradiated wavelength, in one embodiment it is provided that a filtering of the reflected and / or transmitted light is carried out in order to select the one wavelength or a wavelength range which comprises the one wavelength. Such a filter is between the security element and the

Detection device arranged. Photoluminescence caused by UV or IR radiation can then be distinguished from the reflection of UV or IR radiation. The luminescent light is blocked by the filter and so can not falsify the transmission or reflection measurement. In particular, in the verification in which the reflection intensity is detected in the non-excited state, such a selection is advantageous in order to distinguish the carried out UV or IR reflection of a triggered luminescence.

In a development of the method, an electrical and / or magnetic field strength is changed in the spatial area in which the security element is located while the excited state is brought about, and the intensity of the light of the one wavelength reflected and / or detected at the security element is detected the intensity of the light transmitted through the security element of the one wavelength is repeatedly performed and a dependence of the detected intensities of the reflected light of a wavelength of the electric and / or magnetic field strength with an expected reflection intensity dependence and / or a dependence of the detected Intensities of the transmitted light of a wavelength of the electric and / or magnetic field strength in each case with an expected

Compare transmission intensity dependence and verify the security element only as true if the dependence of the detected reflected intensities with the expected reflection intensity dependence and / or the dependence of the detected transmitted intensities with the expected transmission intensity dependence match. This development also makes it possible to empirically find the "optimal" field strength of the electric and / or magnetic field at which a maximum interaction, i.e. a maximum reflection on the security element and / or a minimum transmission of the light of a non-visible wavelength occurs.

Multiple detection of the intensities during induction can also only be done to empirically mediate the correct structure excitation without evaluating the intensity dependence for verification.

As the angle of incidence, an angle in the range between 10 ° and 40 °, measured against a surface normal of the substrate of the security element, is preferably selected. In particular, in embodiments in which the colloidal particles are not arranged in the structure-excited state to a lattice structure which reflects the light of a visible wavelength at all angles of incidence, can also

Angular dependence of the observed reflected intensity or the transmitted intensity at the at least one wavelength can be observed in the structure-excited state.

If the security structure of the security element is structured laterally, for example in such a way that alphanumeric characters, pictograms or the like are printed on the substrate layer with the structure color and information is thus coded, the reflected intensity and / or transmitted intensity is dependent on spatially resolved detection from the structure excitation, the information stored by the structuring hidden information in the non-structure excited state and detectable in the structure-stimulated state.

The security element and also a security document for which one wavelength is transparent in the non-structure-excited state is preferred. Detection of non-visible transmitted or reflected light may be via a substrate layer which contains luminescent agents which are not excitable with light in the visible wavelength range, but exhibit a luminescence upon irradiation with the light of a wavelength in the non-visible wavelength range.

The invention will be explained in more detail with reference to a drawing. Hereby show:

1 a - 1 c are schematic representations of a microcapsule of a structural color for

Explain a texture color effect, depending on a texture stimulus;

Fig. 2a - 2c is a schematic representation of microcapsules for explaining a

Structure color effect in a second embodiment;

3a shows schematic plan views of a security document with a

Security element according to a first embodiment, in which a

Structure color is used which contains microcapsules;

FIG. 3b is a schematic sectional view of a security document according to FIG.

3a;

4a, 4b are schematic representations of a security document similar to that of Figures 3a and 3b during a luminescence excitation without a structure excitation (4a) and with a structure excitation (4b).

5abis 5e schematic representations similar to those of Figure 4a and 4b, which illustrate the optical behavior at different excitation levels.

Fig. 6a is a schematic diagram of the different

Excitation strengths in the FIGS. 5a to 5e detected reflected intensities;

Fig. 6b is a schematic diagram of the for the different

Excitation intensities detected in Figs. 5a to 5e transmitted

intensities; 7 shows a schematic exploded view of a security document with a security element; and

8 is a schematic flow diagram of a verification method.

1 a to 1 c and 2 a to 2 c, the mode of operation of different structural colors is to be explained schematically by way of example, which in each case

Microcapsules 10 included. The same technical features are provided in the figures with the same reference numerals. A structural ink contains a large number of such microcapsules, which are responsible for the color impression or the color of the structure color. Each of the microcapsules 10 has a shell 11 containing a transparent substance 12 containing colloidal particles, e.g. Nanoparticles 13, includes. The sheath 1 1 is formed of a transparent material. The substance 12 is also transparent and represents a fluid in which the nanoparticles 13 in the

Embodiments of Fig. 1 a to 1 c, 2a to 2c can move. The nanoparticles are, for example, clusters of iron oxide with a charged layer or else

Plastic nanospheres with a charged coating. In other

Embodiments may also be paramagnetic particles. With regard to specific embodiments of both the sheaths, the substances contained therein and the nanoparticles, reference is made in particular to EP 2 463 11 1 A2. In addition, structural inks containing such microcapsules and resulting in visible wavelength range dyeing are also available from Nanobrick, Gyeonggi-do, Korea.

In the embodiment of Fig. 1 a to 1 c, the colloidal nanoparticles in the field-free space, which is shown in Fig. 1 a, arranged irregularly. The microcapsules 10 of the colloidal nanoparticles have no special optical property, so that they do not significantly influence the color impression of the structure color in which they are contained. This can thus be regarded, for example, as almost transparent in the printed state. If an electric field with a field strength E1 is applied, the charged nanoparticles align themselves to form a lattice-like crystal structure 15. This is shown in FIGS. 1 b and 1 c. Since the nanoparticles themselves carry a charge, this leads to a repulsion between them. A ratio of the electric field strength E1 or E2 to the own repulsion due to the charge determines a lattice spacing of the nanoparticles. Another factor is the Particle size. If an interaction with light of a wavelength in the UV wavelength range is to be brought about, the particle size must be selected to be correspondingly small.

The crystal structure thus formed has characteristics of a photonic crystal. In this, for some wavelengths, propagation is only along certain

Spatial directions possible. For other wavelengths, propagation may not be possible in any direction. This means that all the light of this wavelength and from all the sinks is reflected. As a result, the color of the microcapsule is conditional. 1 b, an infrared wavelength component is reflected at the field strength E 1, for example when illuminated with "white" light from a black body radiator. because the ratio between the force due to the external electric field and the repulsive force between the similarly charged nanoparticles is given a different ratio, thereby changing the crystal structure so that, for example, the "white" light of a black body radiator reflects a UV component, so that the microcapsule show a UV wavelength range for a reflection and have a "UV color." This is shown in Fig. 1 c.

In FIGS. 2a to 2c, another embodiment of microcapsules 10 is shown schematically. These differ in that the colloidal particles already in the field-free space in the microcapsule 10 have a crystal structure 15, so that from the white light of a black body beam, for example, a color component of the far infrared (FIR) is reflected. As the field strength increases, the distance between the particles in the crystal lattice decreases, so that a near infrared (NIR) color component is now reflected. If the field strength is further increased (FIG. 2c), the grid spacing becomes even smaller, so that again a color component of the near infrared (NIR) is reflected again.

Analogously, this is also transferable to the visible and UV wavelength range.

In Fig. 3a, the plan view of a security document 100 is shown schematically, on which a security element 1 10 is applied as a security structure in the form of a printing with a here designated as IR structure color printing preparation. When IR structure color is a printing preparation, in which the structure-excited state is reflected by the microcapsules of the structure color IR light. In the illustrated embodiment, the security element is formed with the security structure as rectangular printing on a substrate. It is understood that any shape and graphics could be printed with the luminescent structure color.

In Fig. 3b is a sectional view of the security document 100 is shown. Evident is a document body, which is formed from one or more substrate layers 160. A surface 165 of one of the substrate layers 160 is printed with a structure color 210. This forms the security feature 1 10. There is one more about this

Covering layer 180 arranged, which for both light in the non-visible

Wavelength range is transparent. The substrate layers 160 may be transparent or opaque or, for example, only in the region in which the surface 165 is printed with the structure color 210, a transparent window for the light from the non-visible wavelength range.

FIG. 4a shows on the left a schematic sectional drawing of a security document 100 with a security feature 110. The security element 110 includes a security structure 15, which is printed with a structure color 210 on a surface 165 of a substrate layer 160. In a plane perpendicular to the plane of the drawing, the security structure 15 has a shape of a letter "A." This is intended to indicate that information is stored via a lateral patterning.The substrate layer 160 is joined to a document body 150 by a cover layer 180. This can for example via a lamination process.

Preferably, the security document 100 is at least in the area of

Security elements 1 10 transparent for the light with a wavelength in the non-visible wavelength range. If, for example, the security element in the structurally excited state is to reflect light with a wavelength in the UV wavelength range, for example at 254 nm, then it is advantageous if at least the materials of the security document 100 except for the structure color 210 for light of the non-visible Wavelength, for example, for 254 nm, are transparent. In the non-structure excited state, the structure color 210 and thus the entire security element 1 10 is transparent to UV light with the wavelength 254 nm. In the illustrated embodiment, the entire Security document for the non-visible wavelength, here for example 254 nm, transparent.

The security document 100 and the security element 1 10 are in the situation shown in Fig. 4a in the non-structural state excited. The

Security element is in a field-free space.

With a UV lamp 300, light 120 of a non-visible wavelength, for example with a wavelength of 254 nm, is irradiated onto the security element 110. At the security element 1 10 reflected light 121 of a wavelength of the non-visible wavelength range is optionally passed through a filter 31 1 and then to a detection device 321st In the simplest case, the detection device 321 may be a photodiode which has a measurement sensitivity at the one wavelength of the incident light 120. The detection device 321 may have an imaging or collection optics, not shown, to direct a plurality of photons on the photodiode. Other embodiments may provide that a CCD camera or the like is used, which also has a measuring capability for the one in the one wavelength of the incident light 120, i. which has a wavelength of the invisible wavelength range. With a CCD camera, a spatially resolved detection of the intensity is possible.

The detection means may further alternatively or additionally comprise a conversion layer which converts incident light 121 of one non-visible wavelength into light 331 of another wavelength, preferably in the visible wavelength range. By way of example, the conversion layer may comprise a luminescent color with luminescent pigments. If, as in the example described, UV light of wavelength 254 nm is to be detected, then the reflected UV light 121 can be converted into light 331 in the visible wavelength range. This can be detected and evaluated by the human eye or a camera, for example a CCD-based camera.

A reflected image 201 does not show reflected light 121. The intensity of the light in the non-visible wavelength range (or an intensity of the visible light 331 generated therefrom) is indicated in each case by a snap-in density. In the non-structural excited state of the security element 1 10 finds no reflection of the irradiated light 120 in the non-visible wavelength range instead. A contour 1 1 1 of the printed security structure 1 15 in the form of an "A" is only to indicate the position of the security structure 1 15 and the structure color 210, which forms the security structure 1 15 drawn.

Even in transmission, the security element 1 15 in Figure 202 is not recognizable. Also, the transmitted light 122 is preferably passed through a filter 312 to a detection device 322. The above with regard to the detection of the reflected light 121 is analogous to the detection of the transmitted light 122. The filter 312 and the detection means 322 may be correspondingly identical to the filter 31 1 and the detection means 321, if the measurement is time-delayed in reflection and in transmission be executed. In some embodiments, only either a measurement is performed in reflection or in transmission. Also in this case, only one filter and one detection device are needed at a time.

A detected image 202 of the transmitted light of the non-visible wavelength is homogeneously bright. The existence of the security element can not be noticed.

FIG. 4b shows the security document and the detection situation according to FIG. 4a in the case where the security element is in the structurally excited state. This is indicated by E-field arrows 350. In reflection, a luminous "A" is indicated in the figure 201. In the area of the safety structure, the incident UV light 121 is reflected: an intensity of the reflected light detected during the structure excitation is greater than the intensity of the reflected light which is responsible for the non-reflected light. structure-inspired state of the structure color 210 of the security structure 1 15 is detected.

Analogously, in transmission the shape "A" of the security structure 15 can be recognized as negative, ie, the lateral shape of the structure color 210 printed on the surface 165 of the substrate layer 160 can be recognized as a dark area against a light background of the transmitted UV light 122 The structure color 210 prevents in

Structured state a transmission of the incident light with the

Wavelength 254 nm. Similarly, the security element can be designed to interact with IR light. The structure color and its colloidal particles as well as the structure excitation need only be adapted accordingly.

FIGS. 5a to 5e show the situation of FIGS. 4a and 4b for a sequence in which the intensity of the structure excitation is increased, for example the electric field strength. Measurements in reflection and in transmission are carried out for different excitation intensities. The respective detected intensities of the reflected non-visible light and the transmitted non-visible light are respectively shown in a spatially resolved representation. A strength of the excitation is schematically indicated in each case over a length of the field arrows causing E-field. The

Excitation field strength increases monotonically from the situation of FIG. 5a to the situation of FIG. 5e. In the case of very low or nonexistent structure excitation in FIG. 5a, the same behavior is shown as in FIG. 4a. Even with a very high structure excitation, which is shown in Fig. 5e, the security element is not visible, that is, there is no reflection of the light with the non-visible wavelength and thus no attenuation in transmission.

From an excitation intensity, which is shown in FIG. 5b, for example, 30% of the incident light is reflected with the non-visible wavelength. The transmission decreases to 70%. If the excitation intensity is further increased, as shown in FIG. 5 c, the reflection increases to approximately 90% and the transmission decreases to approximately 10%. FIG. 5d illustrates the situation in which the maximum reflection of the incident light with the non-visible wavelength takes place, for example ideally a reflection of 100%. The transmission then drops to 0%.

The reflection intensity and the transmission intensity are for a place of

Safety structure of the security element respectively shown schematically in Fig. 6a and 6b graphically. Such a dependence of the reflection intensity of the

Structure excitation intensity and a dependence of the transmission intensity on the structure excitation intensity can likewise be used to verify the security element. Only if the structure color is identical in its properties to a structure color with which authentic security elements are manufactured, the same dependence of the reflection or transmission results for the light of a selected wavelength length in the non-visible wavelength range, as expected becomes. The procedure described with reference to FIGS. 5a to 5e can also be chosen in order to find the optimal structure excitation.

In Fig. 7 is an exploded view of a security document is shown schematically. The security document 30 comprises a total of five substrate layers 31 - 35 in the illustrated embodiment. Only the uppermost two substrate layers 31, 32 must be made transparent to light of a non-visible wavelength, in order to be able to execute reflection on the structure-enhanced security structure of the security element, which is printed on the middle substrate 33. On the substrate layers 32 and 34 adjoining the middle substrate layer 33, an electrically conductive planar or else grid-like structure is applied as the electrode 41, 42. For example, such an electrode 41, 42 can be formed transparently by means of zinc sulfite. However, it is also possible that the electrode 42 arranged on the substrate layer 34 below the safety structure 15 is designed as a metal layer or metal grid. If the grid lines are chosen fine enough, the

Electrode 41 can also be formed on the substrate layer 32 by means of metallic wires or opaque conductive printing structures in the form of a grid, which has a high light transmission in the range of above 50% to preferably 90% in the visible wavelength range. However, it is particularly preferable to use a transparent electrode. The electrodes 41, 42 are different

Substrate layers with contacts 51, 52 on the uppermost substrate layer 31 in

assembled state contacted. Corresponding electrodes 53, 54 are correspondingly provided with a conductive structure in the form of a coil on the middle

Substrate layer 33 contacted. This encloses the safety structure 15. When a current is passed through the conductor loop 55, a magnetic field is created in the region of the safety structure 15. Thus, particles which are paramagnetic can be aligned to a crystal structure similar to charged particles via an electric field.

The uppermost and lowermost substrate layers 31, 35 serve essentially as

Protective layers. All substrate layers 31, 35 are preferably over

High temperature lamination method joined together. It is understood that additional additional security features may be incorporated into the security document 30 in any combination, such as security prints, holograms, other diffractive structures, electronic circuits, etc. FIG. 8 schematically shows a flow chart of a verification method 500. First, a security element is provided, for example, integrated in a security document 510. Subsequently, field freedom in the area of the security element is brought about 520. Subsequently, an irradiation of light with a wavelength in the non-visible wavelength range 530 takes place. During irradiation of the light with a wavelength in the non-visible wavelength range, detection of the light with the wavelength possibly reflected by the security structure and / or transmitted through the security structure takes place in the non-visible

Wavelength range 540 instead. During the irradiation, for example, a spatially resolved detection of the reflected light of the one wavelength in the non-visible wavelength range 541 and / or a detection of the transmitted light of the one wavelength in the non-visible wavelength range 542 or both. Subsequently, a structure excitation is carried out 620, for example by generating an electric field in the region of the security element or else a

magnetic field, so that a structural excitation of the structure of the color

Security structure of the security element takes place. Once again there is an irradiation of the light with a wavelength in the non-visible wavelength range 630 and a detection of light of the one wavelength in the non-visible wavelength range 640. This can be a spatially resolved detection of the reflected light 641 and / or a spatially resolved detection of the transmitted light of the one wavelength in the non-visible wavelength range 642. The intensities detected in method steps 540 and 640 are compared with one another 710. In this case, the intensity of the reflected light of the wavelength in the non-visible wavelength range determined in the non-structure-excited state serves as the expected reflection intensity, which depends on the intensity of the reflected light in the structure-excited state of FIG

Security element must be exceeded. The same applies to the transmission, wherein the transmitted intensity detected in the structure-excited state must fall below a transmission intensity derived from the detected intensity of the non-structure-excited state in order to be able to verify the security element as genuine. Based on the comparison results or a verification decision is thus made 720, indicating whether the security element is real or not. Finally, the verification decision is issued 730. It turns out that in simple

Embodiments only the transmission or the reflection can be evaluated. It can also be applied to measurements in the non-structural state at all simple embodiments are dispensed with and a value can be specified as reflection intensity, which must be exceeded in the structure-stimulated state. The same applies to the transmission intensity to be undercut.

It is understood that only exemplary embodiments are described here. The features described in the different embodiments may be combined in any combination for realizing the invention.

LIST OF REFERENCE NUMBERS

10 microcapsule

1 1 case

12 substance

13 colloidal particles

15 grid structure

30 security document

31 - 35 substrate layers

41, 42 electrodes

51 - 54 contacts

55 conductor loop

100 security document

1 10 security element

1 1 1 Contour of the safety structure

1 15 security structure

120 luminescence excitation

121 reflected light

122 transmitted light

150 document bodies

160 substrate layers

165 surface

180 cover layer

201 figure (in reflection)

202 figure (in transmission)

210 structure color (without luminescent pigments)

300 UV lamp

31 1 filter

312 filters

321 detection device

322 detection device

331 converted light

332 converted light

350 electric field arrow

500-730 process steps R observation in reflection / incident light

T viewing in transmission / transmitted light

Ε _3Α (λ = A | _R | λ _υν ) (electric) field strength of the structure _excitation , which leads to a

Crystal structure that affects light of wavelength A, _R or λ _υν affects A | _R Wavelength of the infrared light

λ _{υν wave} length of the UV light

Claims

Claims. Claims

1 . Comprising security element (1 10) with excitation-dependent alternating angle with light in the non-visible wavelength range

a substrate layer, and

a safety structure (1 15) formed on the substrate layer and formed with a structural ink (210) comprising microcapsules (10) in which colloidal particles (13) are contained, which by means of a structure excitation, which form an electrical or / and magnetic field, can be arranged in relation to each other in a crystal-like structure and / or can be remodeled, wherein the crystal-like structure (15) via the structure excitation influenceable and / or adjustable reflection and / or transmission properties for light, characterized in that

the microcapsules (10) in the non-structure excited state for at least one wavelength in the non-visible wavelength range an increased

Transmissionsvermögen and a reduced reflectance and the microcapsules (10) in the structure-excited state, in the field of

Microcapsules (10) an electrical and / or a magnetic field generated via the structure excitation exist, a reduced transmittance and an increased compared to the non-structure excited state

Have reflectivity.

2. Security element (1 10) according to claim 1, characterized in that the

Structure color (210) in the non-structure excited state increased

Transmittance and the reduced reflectivity for at least one wavelength in the UV wavelength range and in the structure-excited state, the reduced transmissivity and increased

Reflectance for this at least one wavelength in the UV wavelength range exists.

3. Security element (1 10) according to claim 1, characterized in that the

Structure color (210) in the non-structure excited state increased

Transmittance and the reduced reflectivity for at least one wavelength in the IR wavelength range and in the structure excited Condition the reduced transmissivity and the increased

Reflectance for this at least one wavelength in the IR wavelength range exists.

A method of verifying a security element (110) comprising a security structure (15) formed with a structural color (210), the structural color (210) comprising microcapsules (10) in which colloidal particles (13) are contained by means of a structure excitation, which comprises forming an electrical and / or magnetic field, in relation to one another

crystal-like structure can be arranged and / or reorganized, wherein the crystal-like structure (15) via the structure excitation influenceable and / or adjustable reflection and / or transmission properties for light, comprising the steps:

a) bringing about the structurally excited state of the security element (1 10) by forming an electrical and / or magnetic field in the region of the security element (1 10),

b) irradiation of light having a wavelength which lies in the invisible wavelength range on the security element (1 10), while the security element (1 10) is in the structure-excited state, and c) detecting an intensity of the at the security element (10 ) reflected light of a wavelength and / or an intensity of the through the

Security element (1 10) transmitted light of the one wavelength, each while the security element (1 10) is in the structure excited state, and

d) comparing the detected reflected intensity in the structure-excited state with an expected reflection intensity and / or comparing the detected transmitted intensity in the structure-excited state with an expected transmission intensity;

e) verifying the security element (1 10) as genuine if the im

structure-excited state detected reflected intensity is greater than the expected reflection intensity and / or the detected in the structure-excited state transmitted intensity is smaller than the expected transmission intensity.

A method according to claim 4, characterized in that in addition, the non-structure-stimulated state of the security element (1 10) is brought about, and

while the security element (1 10) is in the non-structural energized state, light having the one wavelength is irradiated to the security element (1 10) and

while the security element (110) is in the non-structure excited state, the intensity of the light of the one wavelength reflected on the security element (110) is detected and / or the intensity of the light of the one wavelength transmitted by the security element (110) is detected,

and the reflected intensity detected in the non-pattern excited state is used as the expected reflection intensity and / or the transmitted intensity detected in the non-pattern excited state is used as the expected transmission intensity, the security element (1-10) being verified as genuine only when the in-structure excited Condition detected reflected intensity is greater than the expected reflection intensity and / or detected in the structure-excited state transmitted intensity is less than the expected transmission intensity.

6. The method according to any one of claims 4 or 5, characterized in that a filtering of the reflected and / or transmitted light is carried out to select the one wavelength or a wavelength range comprising the one wavelength.

7. The method according to any one of claims 4 to 6, characterized in that to bring about the non-excited state, a field freedom in a

Space is made in which the security element (1 10) is located.

8. The method according to any one of claims 4 to 7, characterized in that the induction of the structure-induced state comprises generating a magnetic and / or electric field in the space region in which the

Security element (1 10) is located.

9. The method according to any one of claims 4 to 8, characterized in that the one wavelength is selected in the UV wavelength range and when irradiated is irradiated by light of a wavelength UV light or alternatively, the one wavelength in the IR wavelength range is selected and irradiated upon irradiation of light of the one wavelength IR light.

10. The method according to any one of claims 4 to 9, characterized in that

during the induction of the excited state, an electric and / or magnetic field strength is changed in the space area in which the security element (110) is located, and detecting the intensity of the at

Security element (1 10) of reflected light of a wavelength and / or the intensity of the security element (1 10) transmitted light of a wavelength is repeatedly performed and a dependence of the detected intensities of the reflected light of a wavelength of the electrical and / or magnetic Field strength with an expected

Reflection intensity dependence and / or a dependence of the detected intensities of the transmitted light of a wavelength of the electric and / or magnetic field strength in each case with an expected

Transmission intensity dependency will be compared and that

Security element (1 10) is verified as true only if the dependence of the detected reflected intensities with the expected

Reflection intensity dependence and / or the dependence of the detected transmitted intensities with the expected transmission intensity dependence match.