EP3033739B1 - Method and apparatus for testing a security element of a security document - Google Patents

Description

The invention relates to a method and a device for testing a security element of a security document.

Value or security documents may contain one or more security elements, depending on a verification of a security element, e.g. the authenticity of the value or security document is verifiable. For example, To identify counterfeits of such documents, it is desirable to provide methods and apparatus for reliably testing such security elements.

It is known that value or security documents may contain so-called effect pigments. These effect pigments can form a security element or be part of a security element. That's how it describes EP 1 748 903 B1 a machine-readable security element for security products. The document describes optically variable, platelet-shaped effect pigments which have at least two and at most four optically clearly distinguishable discrete colors under at least two different illumination or viewing angles. Furthermore, the security element may contain at least one particulate substance having electroluminescent properties.

• Messen ellipsometrischer Größen für mindestens eine definierte Stelle auf einer Oberfläche des Erzeugnisses,
• Vergleichen der gemessenen ellipsometrischen Größen mit mindestens einer zuvor archivierten Kodierung und
• Feststellen einer Übereinstimmung der gemessenen ellipsometrischen Größen mit der archivierten Kodierung oder einer der archivierten Kodierungen oder Feststellen einer Nicht-Übereinstimmung mit jeder archivierten Kodierung.

The DE 10 2007 063 415 A1 discloses a method and corresponding apparatus for recognizing a product or information relating to the product. The method identifies a hidden coding carried by the product, the coding being given by a set of ellipsometric parameters, the method comprising the steps of:

• Measuring ellipsometric quantities for at least one defined location on a surface of the product,
• Comparing the measured ellipsometric quantities with at least one previously archived coding and
• Determining a match of the measured ellipsometric quantities with the archived encoding or one of the archived encodings, or determining a mismatch with each archived encoding.

The US Pat. No. 6,473,165 B1 discloses an automated verification system for authenticating an object with an optical security feature. The verification system includes an optical system, a transport apparatus, and an analyzer. The optical system comprises one or more light sources for generating a narrowband or broadband light beam. The transport apparatus cooperates with the light sources and is designed such that the object is positioned such that one or more light beams strike a section in which the security feature is to be arranged. The analyzer receives the reflected or transmitted light rays from the object and is adapted so that optical properties of the light rays at different angles and / or wavelengths are analyzable to verify the authenticity of the object.

The WO 2004/013817 A2 discloses an apparatus and a method for processing value documents, comprising a checking device for checking a security element of the value document, in particular for checking the type and / or authenticity and / or fitness of security elements, which exhibit an optically variable effect, in which the security element differs Viewing angles produces different visual impressions.

The EP 1 867 977 A1 discloses a method and apparatus for detecting the presence of optically variable materials in or on a surface and, more particularly, detecting and identifying optically variable materials in or on printed or coated surfaces.

Verification can be done depending on the effects produced by the optically variable effect pigments. For example, For example, a color shift effect generated by the optically variable effect pigments is available for verification.

However, verification of an effect produced by optically variable effect pigments, especially the color shift effect, may be difficult or impossible in certain applications. It is also possible that the effect produced by optically variable effect pigments, for example the color-shift effect, can be imitated with the aid of other effect pigments. Thus, the optical verification methods that operate based on the generated effect can produce an optically variable effect pigment although there is actually another effect pigment present, thereby causing a mis-verification.

It is also known to use optically variable effect pigments as Feldverdrängerelemente together with electroluminescent pigments. Electroluminescent pigments enable verification as a function of emitted electroluminescent radiation when such an electroluminescent pigment is excited, for example by an electric field. In some application scenarios, such as ATMs, such suggestion and verification may also be difficult or even impossible. Therefore, it may be desirable to perform a verification independent of the electroluminescent radiation.

The technical problem therefore arises of providing a method and a device for the reliable testing of a security element of a security or security document, which permit reliable testing and extend a field of application of such a check.

The solution of the technical problem results from the objects with the features of claims 1 and 6. Further advantageous embodiments of the invention will become apparent from the dependent claims.

It is a basic idea of the invention to illuminate a security element with predetermined illumination parameters and to determine an intensity of a part of the light reflected by the security element at different reflection angles polarized with a certain polarization. Depending on the intensity, it can then be concluded that there is an effect pigment in the security element and optionally a specific type of effect pigment. A method is proposed for checking a security element of a security document. The security element may be located or contained in or on the security document.

The security element may contain at least one substance with optically variable properties. The substance may in particular be a particulate, preferably a powdery substance. A particulate substance may in particular also comprise platelet-shaped particles. Also, the substance may be present in the form of a pigment.

For example, the security element may contain so-called field displacement elements that form the substance with optically variable properties. Field displacement elements may be formed, for example, of dielectric material having a suitably high selected dielectric constant or constants. Due to the field displacement elements, an externally impressed electric field due to the suitably highly selected dielectric constant and due to the field displacement caused thereby in the region of gaps of the field displacement elements can be increased. This allows in Advantageously, the field strengths required for exciting the electroluminescence of electroluminescent pigments in said gaps, wherein the field displacement elements, in particular with regard to the size of the spaces left between them for the desired reinforcement effect can be suitably dimensioned. A particularly effective field compression in the gaps left by the field displacement elements can be achieved by forming the field displacement elements of electrically conductive material so that they form electrically isolated, so-called "floating" electrodes from their surroundings.

Field displacement elements can have a lateral size of up to about 500 μm, in particular a size between 2 μm and 100 μm.

For a specific influencing and focusing of the electric field that can be adapted to the electroluminescent pigments used, the field displacement elements are advantageously applied to a support body of the security document by printing technology, for example using a customary printing method such as gravure printing or screen printing technology.

Also, the field displacement elements or at least a part thereof in the form of having a dielectric constant of more than about 50, preferably as electrically conductive pigments, in addition to the electroluminescent pigments may be incorporated in a marking layer forming the security element.

However, the proposed method is also suitable for testing a security element with an optically variable substance, which is not designed as a field displacement element or comprises such field displacement elements. It is also not absolutely necessary that the security element contains an electroluminescent substance, for example electroluminescent pigments.

The substance with optically variable properties can also be referred to as a so-called effect pigment or comprise such effect pigments. The substance with optically variable properties can under different lighting and / or Viewing angles leave a different visually perceptible color and / or brightness impression. For different color impressions, this property can be called a color flop. In particular, substances which have or produce a color flop produce in the security elements produced therewith non-duplicable color and gloss impressions which are readily perceptible to the naked eye without any aids.

The optically variable substance may have at least two different illumination or viewing angles at least two and at most four, but preferably at two different illumination or viewing angles two or three different illumination or viewing angles, three optically clearly distinguishable discrete colors. Preferably, only the discrete shades and no intermediates are present, i. a clear change from one color to another color can be seen in tilting the security element containing the optically variable substance. On the one hand, this feature makes it easier for the observer to recognize the security element as such and, at the same time, makes it more difficult to copy the feature, since color flop effects can not be copied or reproduced in the commercially available color copiers.

In order to be able to develop their full optical effect, it is advantageous if the substance used according to the invention with the optically variable properties in the security element containing it is present in an oriented form, i. that they may be aligned nearly parallel to the security element surfaces of the security document.

In particular, platelet-shaped effect pigments can be used as the optically variable substance. As platelet-like effect pigments, for example, the commercially available interference pigments, which are available under the names Iriodin®, Colorstream®, Xirallic®, Lustrepak®, Colorcrypt®, Colorcode® and Securalic® from Merck KGaA, Mearlin® from Mearl , Metallic effect pigments from Eckhard and goniochromatic (optically variable) effect pigments such as Variochrom® from BASF, Chromafflair® from Flex Products Inc., Helicone® from Wacker or holographic pigments from Spectratec and other similar commercially available pigments. These However, enumeration is to be considered as illustrative and not restrictive.

In particular, it may be known beforehand under which angle of incidence in the case of white light irradiation which hues are reflected by the optically variable substance.

A security document is any document that is a physical entity that is protected against unauthorized creation and / or corruption by security features. Security features are features that make it difficult to falsify and / or duplicate compared to a simple copy at least. Physical entities that include or form a security feature may be referred to as security features or include security features. A security document may include multiple security features and / or security elements. As defined herein, a security document is always a security element or includes such. Examples of security documents, which also include value documents representing a value, include, for example, passports, ID cards, driving licenses, identity cards, access cards, health insurance cards, banknotes, postage stamps, bank cards, credit cards, smart cards, tickets and labels.

The proposed method comprises the method steps described below.

In a first step, the security element or an area of the security document in which the security element is arranged is illuminated with at least one predetermined illumination parameter. This can e.g. done by a light source.

Illumination parameters include, for example, an illumination angle. The illumination angle here denotes an incident or incidence angle of the light. This angle of incidence may be defined in an incident plane of light as an angle between an incident light and a normal vector of a surface of the security element or security document. A ray of light from the incoming light in this case runs in the plane of incidence which is oriented orthogonally to the previously explained surface of the security element or of the security document.

Further, a lighting parameter may be a wavelength of the incident light. Further, a lighting parameter may be a polarization state of the incident light. A polarization state can be described, for example, as a function of a polarization azimuth and / or a polarization-related ellipticity. In particular, a lighting parameter can also be an intensity of the incident light.

Of course, it is conceivable that further illumination parameters of the incident light are selected as predetermined illumination parameters.

In particular, the at least one illumination parameter can be a user-adjustable illumination parameter.

In a second method step, the light reflected by the security element is filtered into a first component having a first polarization direction. Hereinafter, the first portion of the reflected light having a first polarization direction is also abbreviated to the first portion. In this case, the light is filtered, which is reflected at a predetermined angle of reflection by the security element or by the security document. Thus, therefore, a component or a component with a specific polarization is filtered out of the light reflected by the security element. For example, a polarization angle of the first portion may be determined in relation to a reflection or deflection plane, the reflection or deflection plane oriented perpendicular to the previously discussed surface of the security document, and a light beam of the reflected light in the reflection or deflection plane , For example, the first portion may have a polarization angle of 90 °. Of course, however, the polarization angle can also assume values other than 90 °. This will be further explained below.

The filtering can in this case by a means for polarization filtering, in particular a so-called polarization filter, take place.

In a third method step, an intensity of the first portion of reflected light is determined, which is reflected at a reflection angle. The reflection angle can be defined here as an angle in a reflection plane of the light as an angle between the reflected light and the normal vector of a surface of the security element or of the security document. A light beam of the reflected light in this case runs in the reflection plane which is oriented orthogonally to the previously explained surface of the security element or of the security document. The reflection plane can also be referred to as a failure plane. The determination of the intensity in this case takes place for at least two mutually different, reflection angles, one of which is the angle of directed reflection.

Furthermore, an angle between a polarization direction of the first component and a reflection plane is selected as a characteristic polarization angle, the characteristic polarization angle being at least dependent on the at least one illumination parameter and the type of substance to be verified with optically variable properties. In particular, the angle between the polarization direction of the first component and the reflection plane is selected such that an intensity of the first component is maximal in comparison to the intensities of the components with the remaining polarization directions. Thus, therefore, a filtering of the first component takes place in such a way that the first component has a maximum intensity relative to different polarization directions. The corresponding polarization angle is characteristic of the type of substance with optically variable properties and dependent on the at least one illumination parameter.

Thus, for example, in preliminary tests and / or simulations for different illumination parameters and different types of substances with optically variable properties, the angle between the polarization direction of the first component and the reflection plane can be determined, below which the first component has the maximum intensity. This can be stored, for example in the previously explained database, as a characteristic polarization angle. Also, the angle between the direction of polarization of the first component and the reflection plane can be one of the test parameters already explained above.

In a subsequent method of testing, then e.g. a means for polarization filtering are arranged such that the reflected light is filtered so that the polarization direction of the first portion and the reflection plane include the characteristic polarization angle.

Since the characteristic polarization angle is also substance-specific, this advantageously results in an increase in the reliability of the identification of a specific type of substance with optically variable properties.

In a fourth method step, a verification of the presence of a substance with optically variable properties is carried out as a function of the intensity of the first portion. In this case, the intensity of the first component can be determined by a means for determining the intensity, for example an optical sensor. In addition, it may be possible to identify a type or a type of the substance having optically variable characteristics depending on the intensity of the first portion. In the following, the type or the type of the substance is abbreviated as a kind. Thus, a verification of the security element can also be made depending on the identified type. One type characterizes a security element which consists of a predetermined material or a predetermined material composition. Also, the verification can be done depending on the angle of reflection, which can be quantified or determined for this purpose.

The proposed method advantageously utilizes two effects produced by the optically variable substance. First, a polarization state of the incident light is changed by the substance having optically variable characteristics. This means that the polarization properties of the light reflected by the security element differ from the polarization properties of the incident light. This effect is similar to the known effect that under a material-specific Brewster angle mainly one of several polarization components of the incident light is reflected.

A second effect is given by the interference of the reflected light rays caused by the substance with optically variable properties. The interference is dependent on a geometric size, in particular a layer thickness of the substance or constituents, in particular pigments, of the substance. Also, the interference depends on orientations of the constituents of the substance with respect to an (idealized flat) surface of the security element or security document. Thus, the interference depends on the inhomogeneity of the surface of the security element. Since incident light can at least partially penetrate the substance with optically variable properties, the interference is also dependent on layers underlying this substance, for example paper layers, with respect to the irradiation direction. The relevant inhomogeneities of a surface of paper may be e.g. be much larger than a thickness of interference layers and, for example, correspond to individual pigment particles or particle agglomerates.

The material composition of the security document and also the security element as well as a distribution and orientation of elements, in particular pigments, of the substance with optically variable properties in or on the security document thus produces a scattering of the incident light.

Both effects cause the effect that a polarized light scattering through the substance with optically variable properties, wherein the polarized light scattering has properties that allow the presence and, as explained in more detail below, optionally a kind of substance with optically variable Verify properties.
It is also possible that, in addition to the two effects described above, scattering effects, which are also produced, for example, by inhomogeneity of the surface of the security element and layers lying below the security element, contribute to polarized light scattering.

In particular, the aforementioned effects can cause the light reflected by the security element, which has certain polarization properties, to have a predetermined intensity at a specific reflection angle.

The above-explained change in the polarization properties may in particular be dependent on the nature of the substance with optically variable properties. Also, the change in the polarization properties may be dependent on the at least one illumination parameter.

The presence of a substance with optically variable properties as a function of the intensity of the first portion can be verified in an unclaimed embodiment if the intensity corresponds to a predetermined intensity or lies within a predetermined intensity interval. In a further unclaimed embodiment, the presence may be verified if the intensity of the first portion is greater than a predetermined intensity or less than a predetermined intensity or is within a predetermined intensity interval of a predetermined intensity.

The predetermined intensity can in this case be determined, for example, in preliminary tests. In preliminary tests and / or by simulation, one or more types of substances with optically variable properties can be illuminated. Various test parameters can be set here. For example, different lighting parameters can be set. Alternatively or cumulatively, different angles of reflection can be set. Further alternatively or cumulatively, an intensity of the first component can be determined for different polarization states of the first component. A polarization state can be described, for example, by a polarization angle. Further alternatively or cumulatively, of course, further adjustable parameters that influence the amount of the intensity of the first portion can be set.

The type of substance, the set test parameters as well as the intensity of the first component detected in dependence on the set test parameters can then be determined e.g. in a memory device, e.g. in the form of a database.

The intensity of the first component determined according to the invention can then be compared with stored intensities in an unclaimed exemplary embodiment, it being possible to verify at least one presence of one of several types of substance with optically variable properties as a function of the comparison. In addition to verifying the presence, the species may also be identified. For example, the Art are identified as the type assigned to a stored intensity, if the intensity of the first component determined according to the invention, when tested with certain test parameters, does not deviate or only by a predetermined amount from this stored intensity, which was determined under the same test parameters. The verification of the type can be successful, for example, if the type identified according to the invention corresponds to a type to be expected for the tested document. Accordingly, verification of the type may not be successful if the species identified according to the invention does not meet the type expected for the tested document.

The proposed method advantageously enables a reliable verification of at least one presence of a substance with optically variable properties. In particular, for the verification of the security element no excitation of electroluminescent pigments as well as no analysis of a color-tilting effect is necessary.

The method comprises the following steps: In a method step, an intensity of the first portion of the reflected light is determined, which is reflected at an angle of directed reflection. The angle of directed reflection corresponds in terms of magnitude to the previously explained angle of incidence, but has a different sign in relation to a common angular convention.

In a further step, an intensity of the first portion of the reflected light is determined, which is reflected under at least one further reflection angle, wherein the at least one further reflection angle is different from the angle directed reflection. The at least one further reflection angle is therefore selected differently from the angle of reflection. In particular, the at least one further reflection angle may be smaller or larger in magnitude than the angle of directed reflection. The at least one further reflection angle can in this case be the previously explained reflection angle.

The intensity of the first portion can, as previously explained, be determined by a means for determining the intensity, for example an optical sensor. It is possible that the first proportion at different angles by the same means for Polarization filtering filtered and whose intensity is determined by the same means for detecting an intensity.

Alternatively, it is possible that the first portion is filtered at reflection under the angle of directed reflection by a first means for polarization filtering and whose intensity is determined by a first means for detecting an intensity, wherein the first portion in reflection at the at least one further angle through filtered another means for polarization filtering and whose intensity is determined by a further means for detecting an intensity.

In a further step, the at least two determined intensities are compared. Verification of the presence of a substance having optically variable properties occurs if the intensity of the first portion at reflection below the at least one further reflection angle is greater than the intensity of the first portion at reflection at the angle of directed reflection.

Of course, the intensity of the first portion may be determined upon reflection among a plurality of further reflection angles, which are all different from the angle-directed reflection.

The presence of a substance having optically variable properties can not be verified if the intensity of the first portion in reflection at the angle of directed reflection is greater than the intensity / intensities of the first portion in reflection below the at least one further reflection angle (s) is.

The presence of a substance having optically variable properties may then be verified if the intensity of the first portion is greater than or less than the intensity of the first portion when reflected at the angle of reflection by at least one of those angle-reflection-different reflection angles or multiple such reflection angles is.

The proposed method advantageously enables a reliable verification of at least one presence of a substance with optically variable Properties by a simple comparison of at least two intensities. Here, the effect is used that the intensity of the reflected light in most materials or material compositions when reflected at the angle of directed reflection has an intensity maximum of the first portion. For example, it was possible to determine in experiments that materials which are used, for example, in a counterfeiting as a substance with optically variable properties, have an intensity maximum of the first component when reflected at the angle of directed reflection.

In a further embodiment, the at least one further reflection angle is selected as a characteristic scattering angle, the characteristic scattering angle being dependent on the at least one illumination parameter and the type of substance to be verified with optically variable properties.

This advantageously enables a reliable verification of the presence of a substance, in particular a predetermined type of substance, with optically variable properties. This in turn advantageously allows even more reliable testing of the security element.

In this embodiment, the effect is utilized that a specific substance having optically variable properties generates the above-explained polarized light scattering such that a maximum of the intensity of the first portion occurs under the substance-specific characteristic scattering angle.

If it is therefore to be checked whether a specific type of substance with optically variable properties is present in the security element, then the at least one further reflection angle can be chosen in accordance with the substance-specific characteristic scattering angle. If the specific substance is actually contained in the security element, then it is assured with great certainty that the detected intensity of the first fraction when reflecting below the characteristic scattering angle is greater than the detected intensity when reflecting at the angle of directed reflection. However, if the intensity of the first component detected under the characteristic scattering angle is smaller, then it can already be ruled out at this time that the specific substance is present in the security element.

In a preferred embodiment, a particular substance having optically variable properties is identified if the intensity of the first portion is at reflection below the characteristic scattering angle and / or corresponds to a predetermined intensity.

In a first alternative, the intensity of the first component can be determined by reflection at a plurality of reflection angles, for example for a plurality of reflection angles of a predetermined angular interval, and thus an intensity profile over a plurality of reflection angles. From this intensity profile, a reflection angle can be determined, below which the intensity of the first component is maximal. Depending on this reflection angle of maximum intensity, the type of substance with optically variable properties can then be identified.

By way of example, the type can be identified as the type associated with a stored characteristic scattering angle if the reflection angle determined according to the invention does not deviate or only deviates by a predetermined amount from this characteristic scattering angle, which was determined under the same test parameters, during testing with specific test parameters. This can be done for example by means of an appropriately designed evaluation.

For this purpose, as previously explained, e.g. in a database, the respective substance-specific characteristic scattering angle for different types of substances with optically variable properties and possibly for different test parameters. This information can be determined for example by preliminary tests.

Alternatively or cumulatively, the intensity of the first portion of the light reflected under the characteristic scattering angle may be compared to predetermined intensity values. For example, the previously explained database may alternatively or cumulatively contain for different types of substances and possibly different test parameters also intensities of the first portion, which are determined under the characteristic scattering angle. This allows advantageously a timely identification of a specific substance with optically variable properties.

For this purpose, the intensity of the first portion can be normalized to an intensity of the incident light. This advantageously makes it possible to reliably determine the intensity even with varying or fluctuating intensities of the incident light.

Thus, in a method for checking a security element of a security document, the security element can be illuminated with at least one predetermined illumination parameter and a light reflected by the security element can be filtered into a first component having a first polarization. Then, a determination of an intensity of the first component in the case of reflection can take place under at least the characteristic scattering angle explained above. A verification of a presence and optionally a verification of a specific type of a specific substance with optically variable properties can take place if the intensity of the first portion corresponds to a predetermined intensity. This advantageously allows a reliable intensity-based verification of a presence as well as an identification of a specific substance with optically variable properties.

In a further embodiment, the light reflected by the security element is divided into the first portion and a further portion having a polarization orthogonal to the first polarization, wherein the verification of the presence of a substance with optically variable properties and / or an identification of a particular type of substance with Optically variable properties in addition depending on an intensity of the further share takes place.

For this purpose, the intensity of the further portion can also be determined. In particular, this can be done for the light reflected at the angle of reflection and for the light reflected at this angle directed reflection different reflection angle light.

In this case, it is possible to verify the presence of a substance having optically variable properties as a function of a difference between the intensity of the first fraction and the intensity of the further fraction. The difference can be evaluated, for example, in the form of a difference or a ratio. For example, if the ratio is greater than a predetermined threshold value, a presence of a substance having optically variable characteristics can be verified.

This advantageously takes advantage of the effect that the reflected light is polarized in a predetermined manner, in particular polarized such that a distribution of intensity over different polarization states has a maximum and a minimum, with 90 ° polarization angle between maximum and minimum.

Alternatively or cumulatively, an identification of a specific type of substance with optically variable properties can additionally take place as a function of an intensity of the further fraction.

For example, the intensity of the further portion may be characteristic of a particular type of substance with optically variable properties.

Also, the difference, in particular the ratio, of the intensity of the first portion to the intensity of the further portion may be characteristic of a particular type of substance.

Thus, advantageously, a particular type of substance having optically variable properties can be more reliably identified. The characteristic intensity of the further portion can, according to the previous explanations, also be stored in a corresponding database.

Thus, in a method for checking a security element of a security document, the security element can be illuminated with at least one predetermined illumination parameter. Then filtering the light reflected by the security element into a first portion having a first polarization and into another portion having a polarization orthogonal to the first polarization respectively. Then, a determination of an intensity of the first portion and a determination of an intensity of the further portion can take place. This can be done in particular for light, which is reflected under the previously explained characteristic scattering angle.

For example, verification of the presence of a substance having optically variable properties may be made if the intensity of the first portion and the intensity of the further portion differ by more than a predetermined amount. For example, the presence can be verified if a ratio of the intensity of the first component to the intensity of the further component is greater than a predetermined threshold value.

Alternatively or cumulatively, a particular type of substance having optically variable properties can be identified as a function of the intensity of the first and further portions. For example, both the intensity of the first portion and the intensity of the further portion may be characteristic of a particular type of substance. Also, the difference, in particular a ratio, of the intensity of the first portion to the intensity of the further portion may be characteristic of the particular type of substance. This may be the case in particular for given test parameters, in particular for the characteristic scattering angle explained above.

For example, in preliminary tests and / or simulations it can be determined which intensities and / or intensity ratio the first and the further components have when a specific type of substance is tested with predetermined test parameters. Depending on these results, a verification can then be carried out, as already explained above.

In a further embodiment, the security element is illuminated with linearly polarized light. This results in an advantageous manner compared to elliptically polarized light, inexpensive measuring device.

As previously explained, the security element may contain the substance with optically variable properties as well as an electroluminescent substance, in particular electroluminescent pigments. In particular, the substance with optically variable properties can contain or form field displacement elements. In this case, before the implementation of the proposed procedure, the Security element with an alternating electric field for exciting the electroluminescent pigments are acted upon. After that, an emitted luminescent light or an emitted luminescent radiation can be detected. In this case, the method according to the invention can only be carried out if emitted luminescence radiation is detected and / or if properties of the luminescence radiation correspond to predetermined properties. Thus, the inventive method can be carried out only if the electroluminescent substance has been successfully verified. Thus, the test according to the invention is carried out only if a presence (of a certain type) of an electroluminescent substance is detected. If the verification of the electroluminescent substance is unsuccessful, the process can be terminated, with the method according to the invention not being carried out for testing.

Alternatively, the method proposed according to the invention may first be carried out for testing, whereby a further verification of the electroluminescent substance takes place only after successful verification of the substance with the optically variable properties. For this purpose, the security element can be acted upon by the alternating electric field for exciting the electroluminescent pigments. After that, the emitted luminescent light or the emitted luminescent radiation can be detected. Verification of the electroluminescent substance may be e.g. take place if emitted luminescence radiation is detected and / or if properties of the luminescent radiation correspond to predetermined properties. If no successful verification of the substance with the optically variable properties, so no verification of the electroluminescent substance is performed.

Also proposed is a device for testing a security element of a security document according to claim 6, wherein the security element can contain at least one substance with optically variable properties.

The device comprises at least one light source for illuminating the security element. The light source can be adjustable here. In particular, illumination parameters of the light source can be adjustable. For example, a wavelength, an intensity, an angle of incidence and / or a polarization state of the light generated by the light source can be adjusted.

Of course, it is conceivable that the device comprises, in addition to the light source, further optical elements, for example optical filters, modulators and means for beam guidance, wherein illumination parameters of the light generated by the light source can be adjusted by means of these optical elements. For example, a polarization state of the incident light can be adjusted by a polarization filter.

Furthermore, the device comprises at least one means for the polarization filtering of the light reflected by the security element. By means of the means for polarization filtering, a first portion of the reflected light can be filtered with a first polarization.

For this purpose, the means for polarization filtering is designed and / or arranged, in particular aligned, such that a polarization direction of the first portion corresponds to the characteristic polarization angle explained above.

Furthermore, the device comprises at least a first means for detecting an intensity of the first portion.

Furthermore, the device comprises at least one evaluation device, e.g. a trained as a microprocessor evaluation. This data and / or signal technology can be connected to the means for detecting an intensity.

By means of the first means for detecting an intensity, an intensity of the first portion of reflected light, which is reflected at a reflection angle, can be determined for at least one reflection angle. By means of the evaluation device, a presence of a substance with optically variable properties as a function of the intensity of the first portion can be verified.

In this case, the device advantageously makes it possible to carry out one of the previously explained methods.

In particular, by means of the first means for detecting an intensity, an intensity of the first portion of reflected light can be determined, which is at an angle reflected reflection. By means of the first means or of a further means for detecting an intensity, an intensity of the first portion of reflected light can be determined which is reflected under at least one further reflection angle, this further reflection angle being different from the angle of directed reflection.

By means of the evaluation device, a presence of a substance with optically variable properties can then be verified if the intensity of the first component is greater than the intensity of the first component in the case of reflection under the angle of reflection when the reflection is below the at least one further reflection angle.

Here, the means for polarization filtering as well as the first means for detecting an intensity can be designed and / or arranged such that only under the angle directed reflection of the first portion is filtered and its intensity is detected.

By means of the first means for detecting an intensity, it is also possible to determine an intensity of the first component in the case of reflection under at least one further reflection angle, which differs from the angle of reflection. For this purpose, an arrangement, in particular a position and / or orientation, of the first means for detecting an intensity and optionally also the means for polarization filtering can be changed such that only light which is reflected under the at least one further reflection angle is filtered and detected. For this purpose, the device may comprise a suitable adjusting device for adjusting the arrangement, in particular the position and / or orientation, of the first means for detecting an intensity and / or the means for polarization filtering.

Alternatively, by means of a further means for detecting an intensity, the intensity of the first component can be determined upon reflection under the at least one further reflection angle. In this case, the device may also comprise a further means for polarization filtering. The further means for detecting an intensity and / or the further means for polarization filtering can in this case be designed and / or arranged such that the first component is filtered exclusively from light which is reflected under the at least one further reflection angle and its intensity is determined.

By means of the evaluation device, the presence of a substance with optically variable properties can be verifiable, if the intensity of the first component is greater than the intensity of the first component in the case of reflection under the angle of directed reflection under the at least one further reflection angle.

The first means for detecting an intensity and / or the at least one further means for detecting an intensity can in this case be spatially fixedly installed. This means that a position and / or orientation of the corresponding means for detecting an intensity is immutable.

The proposed device allows this advantageously to carry out one of the previously explained methods.

In a further embodiment, at least one reception angle of the first means for detecting an intensity can be set. This means that a relative position and / or relative orientation of the first means for detecting the security element can be changed. Thus, for example, a position and / or orientation of the first means for detecting an intensity and / or a position and / or orientation of the security element can be changed. In particular, the reception angle can be selected such that a desired reflection angle is set.

Alternatively or cumulatively, the device comprises at least one further means for detecting an intensity of the first portion, wherein a receiving angle of the at least one further means for detecting an intensity is adjustable. This also means that a relative position and / or relative orientation of the further means for detecting an intensity can be changed to the security element.

Of course, also a position and / or orientation of the means for polarization filtering and / or the further means for polarization filtering can be changed. Thus, therefore, a receiving angle of these means for polarization filtering can be adjusted.

This advantageously makes it possible to detect intensities of the first component for a plurality of reception angles and thus reflection angles. Thus, by means of the proposed device also different types of substances with optically variable properties can be identified, these different types having different characteristic scattering angles.

In a further embodiment, by means of the at least one means for polarization filtering from the light reflected from the security element additionally a further portion with a polarization orthogonal to the first polarization can be filtered. In this case, the device may comprise a means for detecting an intensity of the further portion.

Furthermore, the first and / or the at least one further means for polarization filtering can be embodied as a polarization beam splitter or as a polarization filter, in particular as a polarization film.

Fig. 1

eine schematische Darstellung der Funktionsweise einer erfindungsgemäßen Vorrichtung in einer ersten Ausführungsform,

Fig. 2

beispielhafte Verläufe von Intensitäten eines ersten Anteils und zweiten Anteils von verschiedenen Arten von Substanzen mit optisch-variablen Eigenschaften,

Fig. 3

eine schematische Darstellung einer erfindungsgemäßen Vorrichtung in einer zweiten Ausführungsform,

Fig. 4

eine schematische Darstellung einer erfindungsgemäßen Vorrichtung in einer dritten Ausführungsform,

Fig. 5

eine schematische Darstellung einer erfindungsgemäßen Vorrichtung in einer vierten Ausführungsform,

Fig. 6

eine schematische Darstellung einer erfindungsgemäßen Vorrichtung in einer fünften Ausführungsform,

Fig. 7

eine perspektivische Ansicht einer erfindungsgemäßen Vorrichtung und

Fig. 8

einen Längsschnitt durch die in Fig. 7 dargestellte Vorrichtung und

Fig. 9

einen Längsschnitt durch eine weitere erfindungsgemäße Vorrichtung.

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

Fig. 1

a schematic representation of the operation of a device according to the invention in a first embodiment,

Fig. 2

exemplary courses of intensities of a first portion and second portion of different types of substances with optically variable properties,

Fig. 3

a schematic representation of a device according to the invention in a second embodiment,

Fig. 4

a schematic representation of a device according to the invention in a third embodiment,

Fig. 5

a schematic representation of a device according to the invention in a fourth embodiment,

Fig. 6

a schematic representation of a device according to the invention in a fifth embodiment,

Fig. 7

a perspective view of a device according to the invention and

Fig. 8

a longitudinal section through the in Fig. 7 shown device and

Fig. 9

a longitudinal section through a further device according to the invention.

Hereinafter, like reference numerals designate elements having the same or similar technical features.

In Fig. 1 is a device 1 according to the invention schematically represents in a first embodiment. The device 1 comprises a light source 2. The light source 2 emits light, which is exemplified by a light beam 3, with an angle of incidence φ ₀ on a security element 4, which may be part of a security document, not shown. The security element 4 contains a substance 5 with optically variable properties, which is designed in particular as an effect pigment. In interstices between particles or elements of the substance 5 electroluminescent pigments 6 are arranged. Here, the substance 5 serves as a field displacement element for field concentration in order to stimulate the electroluminescence of the electroluminescent pigments 6.

In Fig. 1 is shown that the angle of incidence φ _{0 is defined} as an angle between a normal direction 7, which is oriented perpendicular to a surface 8 of the security element 4 and the security document, not shown, and the light beam 3. The in Fig. 1 illustrated light beam 3 extends in an incidence plane, not shown, which is also oriented perpendicular to the surface 8 and in the straight line which are parallel to the normal direction 7, are arranged. It is shown that the light beam 3 comprises a first portion ELp which has a plane of polarization which extends in the plane of incidence. In addition, the light beam 3 has a further portion ELs whose polarization plane is oriented perpendicular to the plane of incidence. But ELp and ELs can also denote arbitrary orthogonal polarization states.

The light beam 3 in this case has a predetermined wavelength and a predetermined polarization state.

The device 1 further comprises a polarization beam splitter 10, a first light sensor 11 and a second light sensor 12. The polarization beam splitter 10 and the light sensors 11, 12 are arranged such that light which is reflected at a predetermined reflection angle φ _R and exemplified by a reflected Light beam 9 is shown, filtered and received.

The reflection angle φ _R is defined as an angle between the normal direction 7, which is oriented perpendicular to the surface 8 of the security element 4 and the security document, not shown, and the reflected light beam 9, wherein the reflected light beam 9 extends in a reflection plane, which is also perpendicular is oriented to the surface 8 of the security element 4 and the security document, not shown, and in the straight line, which extend parallel to the normal direction 7, are arranged.

The reflected light includes a first portion RLp having a polarization direction that extends in the reflection plane. The reflected light also contains a further component RLs with a polarization direction perpendicular to the polarization direction of the first component RLp. By the polarization beam splitter 10, the first portion RLp and the further portion RLs from the reflected light beam 9 is filtered, wherein an intensity I (see Fig. 2 ) of the first portion RLp by the first light sensor 11 and an intensity I of the further portion RLs by the second light sensor 12 is determined.

It is also possible to determine intensities I for a plurality of reflection angles φ _R. For this purpose, a position and orientation of the polarization beam splitter 10 and the light sensors 11, 12 can be changed such that a predetermined number of different reflection angles φ _{R is} set. For each of these reflection angles φ _R , the intensities I of the first component RLp and the further component RLs can then be determined.

For example, intensities for a predetermined number of, e.g. B. equidistant, reflection angles φ _R are detected in an angular interval of 0 ° to 90 °.

It may also be possible to determine a maximum intensity I of the first component RLp and the corresponding reflection angle φ _R. This corresponding reflection angle φ _R can also be described as a characteristic scattering angle φ ₂ (see Fig. 3 ), which is substance-specific. In addition, the characteristic scattering angle φ _{2 may be} dependent on a wavelength of the incident light. The characteristic scattering angle φ ₂ can also be dependent on properties of the security element 4, in particular on a surface orientation and / or roughness of the security element 4. Thus, it may be possible to determine the presence and the nature of the substance 5 or of the security element 4 as a function of the characteristic scattering angle φ ₂ .

For example, the presence of a substance 5 can be verified by adjusting a position and orientation of the polarization beam splitter 10 and the light sensors 11, 12 such that the reflected light is at an angle φ ₁ (see FIG Fig. 3 ) Reflected reflection and its intensity I is detected. The angle of directed reflection φ ₁ corresponds in terms of magnitude to the angle of incidence φ ₀ , but is oriented in the relation to the normal direction 7 opposite to the angle of incidence φ ₀ .

Further, the position and orientation of the polarization beam splitter 10 and the light sensors 11, 12 can be adjusted so that the reflected light is reflected at a further reflection angle φ _R , which is different from the angle φ ₁ directed reflection. In this case too, intensities I of the different polarized components RLp, RLs of the reflected light can be detected. The presence of the substance 5 can be verified in this case, if the intensity I of the first portion RLp of the reflected light, which is reflected at the angle φ ₁ reflection, is less than the intensity of the first portion RLp of the reflected light, the the further reflection angle φ _{R is} reflected.

It is also possible, a presence and optionally a kind of substance 5 depending on a difference, for. B. depending on a difference or a ratio, the intensity I of the first portion RLp and the intensity I of the further portion RLs at one or more reflection angles φ _R to determine. So z. B. the difference between the intensities I of the shares RLp, RLs at a predetermined Reflection angle φ _R , in particular the previously described characteristic scattering angle φ ₂ , or the course of the difference over several different reflection angle φ _R characteristic of the type of substance 5, that is substance-specific, his. So z. Example, a certain type of substance 5 are identified, if the difference between the intensities I of the shares RLp, RLs one, z. B. determined by preliminary tests, difference corresponds or a course of the difference over several reflection angle φ _R corresponds to a predetermined course or deviates from it only by a predetermined small amount thereof.

Of course, a position and orientation of the polarization beam splitter 10 and the light sensors 11, 12, in particular multiple, be changed until the difference, for example, the difference or the ratio between the intensity I of the first portion RLp and the further portion RLs is maximum. The corresponding reflection angle φ _R and / or the corresponding polarization angle of the first component, which can be adjusted by changing the orientation of the polarization beam splitter 10, can be substance-specific, ie characteristic of a specific type of substance 5. Depending on the corresponding scattering angle φ _R and / or the corresponding polarization angle of the first component RLp, the presence and a type of a specific substance 5 can thus be determined.

For all previously explained methods for testing, it may be necessary for each type of substance 5 and for different test parameters, eg illumination parameters, reflection angle φ _R and / or polarization angle, the intensities I and / or differences between the intensities I, for example in FIG To determine preliminary tests. These relationships can then be stored, for example, in a memory device, e.g. In the form of a database. This then allows the proposed verification depending on the stored type, test parameters and values.

In Fig. 2 is an example of an intensity profile of an intensity I of the first portion RLp and the other portion RLs (see Fig. 1 ) for three different types of substances 5a, 5b, 5c for different reflection angles φ _R. It can be seen that the intensity profiles of the intensity I of the first component RLp each have a global maximum in an angular range of 10 ° to 90 °. For a first substance 5a occurs Maximum at a reflection angle φ _R of 60 °. For a second substance 5b, the maximum occurs at a reflection angle φ _R 50 °. In a third substance 5c, the maximum occurs at a reflection angle φ _R of 65 °. The aforementioned angles of maximum intensity I correspond to characteristic scattering angles φ ₂ (see Fig. 3 ) of the various substances 5a, 5b, 5c and are thus substance-specific.

Dotted lines show intensity profiles of the further portion RLs (see Fig. 1 ) of the various substances 5a, 5b, 5c are represented by different reflection angles φ _R. These are approximately constant for different reflection angles φ _R and have no or only a difficult-to-identify global maximum. However, it can be seen hereby that a difference between intensities I of the first components R Lp and the intensities I of the further components R Ls of the substances 5 a, 5 b, 5 c is also maximal for the corresponding characteristic scattering angle φ ₂ .

In Fig. 3 a further embodiment of a proposed device 1 is shown schematically. This corresponds, unless otherwise stated, the in Fig. 1 illustrated device. 1

In addition to the in Fig. 1 illustrated device 1 comprises the in Fig. 3 illustrated device 1 a polarizing filter 13, through which a desired polarization state of the incident light beam 3 is set. Furthermore, the device comprises a wave plate 14, which may be formed as λ / 4-plate, for example. Furthermore, the device 1 comprises a beam splitter 15, which filters out a predetermined portion 17 of the incident light beam 3 from the incident light beam 3. The predetermined proportion 17 may be, for example, 5%. The predetermined portion 17 is detected by a light sensor 16, which may be formed for example as a photodiode, and determines its intensity. This allows a normalization of intensities I (see Fig. 2 ) of the various components RLp, RLs of reflected light beams 9a, 9b to an intensity of the incident light beam 3. Thus, a verification independent of different intensities, in particular also be performed independently of intensity fluctuations of the incident light beam.

The incident light beam 3 in this case has a predetermined wavelength, a predetermined polarization state and a predetermined angle of incidence φ ₀ .

Furthermore, the device 1 comprises a first polarization beam splitter 10a and a further polarization beam splitter 10b. Likewise, the device comprises a first light sensor 11a, a second light sensor 12a, a third light sensor 11b and a fourth light sensor 12b.

The first polarization beam splitter 10a and the first and the second light sensors 11a, 12a are arranged and configured in the device 1 in such a way that a first reflected light beam 9a, which is reflected by the security element 4 at an angle φ ₁ , is filtered and the intensities of a first portion RLp and another portion RLs of this first reflected light beam 9a are detected. The first polarization beam splitter 10a is in this case according to the in Fig. 1 formed polarization beam splitter 10 is formed. In particular, the first light sensor 11a detects the intensity of the first portion RLp of the first reflected light beam 9a, and the second light sensor 12a detects the intensity I of the further portion RLs of the first reflected light beam 9a.

The further polarization beam splitter 10b, the third light sensor 11b and the fourth light sensor 12b are in this case arranged and formed in the device 1 such that a further reflected light beam 9b, which is at a characteristic scattering angle φ _{2 of} a substance 5 to be verified (see Fig. 1 ) is reflected, filtered and the intensities I of the first portion RLp and the further portion RLs are detected. Here, the intensity of the first portion RLp of the further reflected light beam 9b from the third light sensor 11b and the intensity I of the further portion RLs of the further reflected light beam 9b are detected by the fourth light sensor 12b.

In the Fig. 3 illustrated device 1 is used in particular the verification of a particular type of substance 5 (see Fig. 1 ). Accordingly, the reflection angle φ _R (see Fig. 1 ) of the further reflected light beam 9b, the characteristic scattering angle φ ₂ , which is specific to the type of substance 5 to be verified.

In Fig. 4 a device 1 according to the invention is shown in a further embodiment. Unlike the in Fig. 3 illustrated device 1 comprises the in FIG. 4 1 shows a first segmented light sensor 18 and a further segmented light sensor 19. The first segmented light sensor 18 in this case has a first detection segment 18a and another detection segment 18b. Accordingly, the further segmented light sensor 19 has a first detection segment 19a and a further detection segment 19b. Various polarization filters 20a, 20b, 21a, 21b are arranged in front of the detection segments 18a,..., 19b in the beam direction of reflected light beams 9a, 9b such that the first segment 18a of the first segmented light sensor 18 has an intensity I of a first portion RLp of a first reflected light beam 9a, wherein the first reflected light beam 9a is reflected at the angle φ ₁ directed reflection. In this case, the first polarization filter 20a filters out the first component RLp from the first reflected light beam 9a. Accordingly, the further polarization filter 20b filters out a further portion RLs from the first reflected light beam 9a, wherein its intensity I is detected by the further detection segment 18b of the first segmented light sensor 18. A first portion RLp of a further reflected light beam 9b is filtered by a further polarization filter 21a, wherein the intensity I of this first portion RLp is detected by the first detection segment 19a of the further segmented light sensor 19. Accordingly, the intensity I of a further portion RLs of the further reflected light beam 9b is detected by the further detection segment 19b of the further segmented light sensor 19, wherein the further portion RLs is filtered out of the further reflected light beam 9b by the further polarization filter 21b. The further reflected light beam 9b is in this case under one for a particular type of substance 5 (see Fig. 1 ) of the security element 4 characteristic scattering angle φ ₂ reflected.

In Fig. 5 a device 1 according to the invention is shown in a further embodiment. Unlike the in FIG. 3 and FIG. 4 In the illustrated embodiments, instead of light sensors 11a, 11b, 12a, 12b, 18, 19, the device 1 comprises a planar light sensor arrangement 22, which is designed as a CCD sensor and comprises a plurality of light sensors. Not shown are polarization filters, which are arranged in the beam direction of reflected light beams 9a, 9b in front of the light sensor array 22 that individual light sensors of the light sensor array 22 intensities I different parts RLp, RLs of the reflected light beams 9a, 9b detect.

In this embodiment, a reflection angle φ _{R of} the reflected light beam 9 a, 9 b whose respective intensity I is determined may be determined depending on a position of the corresponding light sensors in the light sensor array 22.

In Fig. 5 It is shown that light sensors, not shown, of the light sensor arrangement 22 detect intensities I of components R Lp, R Ls of a first reflected light beam 9 a, which is reflected by the security element 4 at the angle φ ₁ directed reflection. Accordingly, further light sensors detect intensities I of fractions RLp, RLs of a further reflected light beam 9b which is reflected by the security element 4 at a characteristic scattering angle φ ₂ , the characteristic scattering angle φ _{2 being} substance-specific for a specific type of substance 5 (see FIG Fig. 1 ).

In Fig. 6 a further embodiment of a device 1 according to the invention is shown. Unlike the in Fig. 4 illustrated embodiment of the device 1 according to the invention comprises in Fig. 6 illustrated device 1 a third segmented light sensor 23. This segmented light sensor 23 has a first detection segment 23a and another detection segment 23b. Polarizing filters 24a, 24b are arranged in the beam direction of a third reflected light beam 9c in front of the detection segments 23a, 23b such that an intensity I of a first component RLp is reflected by the first detection segment 23a and an intensity I of a further component RLs of the third by the further detection segment 23b Beam 9c is detectable.

The third segmented light sensor 23 can serve to detect intensities I of portions R Lp, R Ls of a light beam 9 c reflected at a further angle φ ₃ , whereby a reliability of the verification can be increased.

In Fig. 6 It is also shown that the light source 2 irradiates a first light beam 3a having a first wavelength and a second light beam 3b having a wavelength different from the first wavelength on the security element 4. Since a characteristic scattering angle φ ₂ can be wavelength-dependent, z. B. the in Fig. 6 represented reflection angle φ _{2 represent} the substance-specific characteristic scattering angle in the case of irradiation of light having the first wavelength, wherein the Further reflection angle φ _{3 represents} a substance-specific characteristic scattering angle in the case of an irradiation of light with the further wavelength.

In the Fig. 6 Thus, the device 1 shown enables the illumination of the security element with two mutually different wavelengths, whereby the detection of intensities I of parts RLp, RLs of reflected light beams 9b, 9c are made possible, which in each case represent characteristic scattering angles when illuminated with the corresponding wavelength. This advantageously allows a further increase in the reliability of a test of the security element 4.

Alternatively, the light source 2 may irradiate a first light beam 3a having a first polarization and a second light beam 3b having a polarization different from the first polarization on the security element 4. This advantageously allows a further increase in the reliability of a test of the security element 4. Alternatively, the polarization states of the incident light beam 3 can be modulated or changed with a time offset. In this case, the measurement data evaluation, ie the evaluation of the intensities I of the portions of the reflected light beam / light beams 9a, 9b, 9c, can be synchronized with a change in the polarization state of the incident light beam 3.

In Fig. 7 is a perspective view of a device 1 according to the invention shown. The device 1 comprises a housing 25. Passage openings 26a, 26b, 26c are arranged in the housing 25. The housing 25 is arranged above the security element 4 and has an internal volume 27 (see FIG Fig. 8 ), which is open towards the security element 4. The passage openings 26a, 26b, 26c connect the inner volume 27 with an outer volume 28.

In a first passage opening 26 a, a light source 2 is arranged, the z. In Fig. 1 emitted light beam 3 emitted.

In the direction of light in front of the light source 2 is the example in Fig. 4 shown polarizing filter 13 and a wave plate 14 is arranged.

In a second passage opening 26b, a first segmented light sensor 18 is arranged. This includes, as in the notes to Fig. 4 already described, a first detection segment 18a and a further detection segment 18b, which are formed by signal technology independently of each other. In the beam direction of a first reflected light beam 9a (see Fig. 4 ) in front of the detection segments 18a, 18b polarizing filters 20a, 20b are arranged, which the Fig. 4 enable detection of intensities I of different components RLp, RLs.

In a third passage opening 26 c, a further segmented light sensor 19 is arranged, which corresponds to the Fig. 4 Explanations is formed.

The through holes 26a, 26b, 26c, in particular central symmetry axes of the through holes 26a, 26b, 26c, are in this case arranged to be received by the first segmented light sensor 18, a first reflected light beam 9a φ at an angle in such a way in the housing 1 ₁ specular reflection is reflected by the security element 4. Accordingly, by the further segmented light sensor 19 arranged in the third passage opening 26c, a further reflected light beam 9b is received, which is reflected by the security element 4 under the characteristic scattering angle φ ₂ .

The first through hole 26a is here arranged and oriented so that light having a predetermined incident angle φ is ₀ irradiated to the security element. 4

In Fig. 8 is a longitudinal section through the in Fig. 7 illustrated device 1 shown. Here, in particular, the inner volume 27 is shown, which is penetrated by both the incident light 3, and the reflected light 9a, 9b.

In Fig. 9 a longitudinal section through a further device 1 according to the invention is shown. Here, in particular, the inner volume 27 is shown, which is penetrated by both the incident light 3, and the reflected light 9a, 9b. Unlike the in Fig. 8 1, a light source 2 is connected via a polarization-maintaining optical waveguide 29 to a light decoupling device 30 arranged in or on the first through-opening 26a, the light being transmitted to the light source 2 Generation of the light beam 3 is passed via the light guide 29 to the light outcoupling device 30 and is coupled out there from the light guide 29 as a light beam 3.

The light beams 9a, 9b reflected by the passage openings 26b, 26c are coupled into further polarization-maintaining light guides 33, 34 by light coupling devices 31, 32, which are respectively arranged in or on these passage openings 26b, 26c. The reflected light is passed through the further light guides 33, 34 to a light sensor arrangement 22 and coupled out via further light extraction means 35, 36 from the further light guides 33, 34. It is shown that different components RLp, RLs of the reflected light beams 9a, 9b are coupled out by the light extraction devices 35, 36 and are radiated onto light sensors (not shown) of the light sensor arrangement 22. These then detect intensities I of components RLp, RLs of the reflected light beams 9a, 9b.

It is thus possible that light for illuminating the security element 4 is guided at least partially via a light guide 29 from a light source 2 to the security element 4. Alternatively or cumulatively, light reflected by the security element can be conducted at least partially via a further optical waveguide 33, 34 from the security element 4 to a light sensor.

The illustrated device 1 advantageously allows a free positioning of the light source 2 and the light sensors relative to a housing 25 or relative to the security element 4. As a result, a usability of the device 1 is improved.

It is possible that a polarization beam splitting and / or a polarization filtering by the light guides 29, 33, 34 and / or the Lichteinkopplungseinrichtungen 32, 33 and / or the light extraction devices 30, 35, 36 takes place.

The light guides 29, 33, 34 may be designed, for example, as optical fibers or glass fibers.

LIST OF REFERENCE NUMBERS

1

contraption

2

light source

3

irradiated light beam

4

security element

5

substance

5a

first substance

5b

second substance

5c

third substance

6

electroluminescent pigment

7

normal direction

8th

surface

9

reflected light beam

9a

first reflected light beam

9b

second reflected light beam

9c

third reflected light beam

10

Polarization beam splitter

10a

first polarization splitter

10b

further polarization splitter

11

first light sensor

12

second light sensor

11a

first light sensor

12a

second light sensor

11b

third light sensor

12b

fourth light sensor

13

polarizing filter

14

wave plate

15

beamsplitter

16

light sensor

17

Proportion of incident light

18

first segmented light sensor

18a

first detection segment

18b

further detection segment

19

second segmented light sensor

19a

first detection segment

19b

further detection segment

20a

polarizing filter

20b

polarizing filter

21a

polarizing filter

21b

polarizing filter

22

Light sensor arrangement

23

third segmented light sensor

23a

first detection segment

23b

further detection segment

24a

polarizing filter

24b

polarizing filter

25

casing

26a

first passage opening

26b

second passage opening

26c

third passage opening

27

internal volume

28

external volume

29

optical fiber

30

Light out-coupling device

31

light coupling

32

light coupling

33

another light guide

34

another light guide

35

further light extraction device

36

further light extraction device

I

intensity

φ _R

angle of reflection

φ ₀

angle of incidence

φ ₁

Angle of directed reflection

φ ₂

characteristic scattering angle

φ ₃

characteristic scattering angle

ELP

first portion of the incident light

ELs

further proportion of the incident light

RLP

first portion of the reflected light

RLs

further proportion of the reflected light

Claims (8)

1. Method for checking a security element (4) of a security document, wherein the security element (4) can contain at least one substance (5) with optically variable properties, comprising the following method steps:

   - Illuminating the security element (4) with at least one predetermined illumination parameter,

   - filtering the light reflected from the security element into a first component (RLp) with a first polarisation direction,

   - determining an intensity (I) of the first component (RLp) of reflected light which is reflected at a reflection angle (ϕ_R), for at least two reflection angles (ϕ_R), wherein an intensity (I) of the first component (RLp) of reflected light, which is reflected at a directed reflection angle (ϕ₁), is determined, wherein an intensity (I) of the first component (RLp) of reflected light, which is reflected at least at one further reflection angle (ϕ_R), is determined, wherein the at least one further refection angle (ϕ_R) is different from the directed reflection angle (ϕ₁), wherein an angle between the polarisation direction of the first component (RLp) and a reflection plane is selected as a characteristic polarisation angle, wherein the characteristic polarisation angle is at least dependent on the at least one illumination parameter and the type of a substance (5) to be verified with optically variable properties,

   - verification of a presence of a substance (5) with optically variable properties as a function of the intensity (I) of the first component (RLp), wherein the presence of the substance (5) with optically variable properties is verified in the event of the intensity (I) of the first component (RLp) at reflection under the at least one further reflection angle (ϕ_R) being greater than the intensity (I) of the first component (RLp) at reflection under the directed reflection angle (ϕ₁).
2. Method according to claim 1, characterized in that the at least one further reflection angle (ϕ_R) is selected as a characteristic scatter angle (ϕ₂, ϕ₃) dependent on the at least one illumination parameter and the type of a substance (5) with optically variable properties which is to be verified.
3. Method according to claim 2, characterized in that a specific type of the substance (5) with optically variable properties is identified in the event of the intensity (I) of the first component (RLp), on reflection under the characteristic scatter angle (ϕ₂, ϕ₃) is a maximum and/or corresponds to a predetermined intensity (I).
4. Method according to any one of claims 1 to 3, characterized in that the light reflected from the security element (4) is divided into the first component (RLp) and a further component (RLs) with a polarisation perpendicular to the first polarisation, wherein the verification of the presence of a substance (5) with optically variable properties and/or an identification of a specific type of a substance (5) with optically variable properties takes place additionally as a function of an intensity (I) of the further component (RLs).
5. Method according to any one of claims 1 to 4, characterized in that the security element (4) is illuminated with linear polarised light.
6. Device for checking a security element (4) of a security document, wherein the security element (4) can contain at least one substance (5) with optically variable properties, wherein the device (1) comprises at least one light source (2) for illuminating the security element (4), wherein
   the device (1) comprises at least one means for the polarisation filtering of the light reflected from the security element (4), wherein the means for the polarisation filtering are configured such as to filter a first component (RLp) of the reflected light with a first polarisation direction,
   wherein
   the device (1) comprises at least one first means for detecting an intensity (I) of the first component (RLp), wherein the device (1) comprises at least one evaluation device, wherein the first means for detecting an intensity (I) is configured such as to determine an intensity (I) of the first component (RLp) of reflected light, which is reflected under a reflection angle (ϕ_R), for at least one reflection angle (ϕ_R), wherein the first means for detecting an intensity (I) is configured such as to determine an intensity of the first component (RLp) of reflected light which is reflected under a directed reflection angle (ϕ₁), wherein the first means or a further means for detecting an intensity (I) is configured such as to determine an intensity (I) of the first component (RLp) of reflected light, which is reflected under a further reflection angle (ϕ_R), wherein the further reflection angle (ϕ_R) is different from the directed reflection angle (ϕ₁),
   wherein an angle between the polarisation direction of the first component (RLp) and a reflection plane is selected as characteristic polarisation angle, wherein the characteristic polarisation angle is at least dependent on the at least one illumination parameter and on the type of a substance (5) to be verified with optically variable properties, wherein the evaluation device is configured such as to verify a presence of a substance (5) with optically variable properties as a function of the intensity (I) of the first component (RLp), wherein the evaluation device is configured such as to verify the presence of the substance (5) with optically variable properties, in the event of the intensity (I) of the first component (RLp), on reflection under the at least one further reflection angle (ϕ_R) is greater than the intensity (I) of the first component (RLp) on reflection under the directed reflection angle (ϕ₁).
7. Device according to claim 6, characterized in that a reception angle of the first means for detecting an intensity (I) is adjustable, and/or the device (1) comprises at least one further means for detecting an intensity (I) of the first component (RLp), wherein a reception angle of the at least one further means for detecting an intensity (I) is adjustable.
8. Device according to claim 6 or 7, characterized in that, by means of the at least one means for the polarisation filtering, a further component (RLs) with a polarisation perpendicular to the first polarisation can additionally be filtered out of the light reflected from the security element (4).

Images