WO2013057277A1

WO2013057277A1 - Method for verifying polarization-dependent security features using a display device

Info

Publication number: WO2013057277A1
Application number: PCT/EP2012/070801
Authority: WO
Inventors: Olga Kulikovska; Olaf Dressel; Jörg Fischer
Original assignee: Bundesdruckerei Gmbh
Priority date: 2011-10-19
Filing date: 2012-10-19
Publication date: 2013-04-25
Also published as: DE102011084821A1

Abstract

The invention relates to a method for verifying a value document or security document (11), comprising the following steps: operating a display device (3) the display area (4) of which emits polarized light (5), arranging, in front of the display area (4), a security document (11) which comprises at least one security feature (2), the transmission properties of which depend on the polarization of the light (5') to be transmitted, detecting the light (5') emitted by the display device (3) and transmitted through the security feature (2) and evaluating the transmitted light (5') and deducing a verification decision therefrom.

Description

A method of verifying polarization-dependent security features using a display device

The invention relates to the field of security documents and in particular to methods for verifying security documents which have at least one security feature which is polarization-dependent.

Security features are understood to mean all features which make it impossible or at least significantly complicate the imitation, falsification, duplication or unauthorized production of an object. A document which has at least one security feature is called a security document.

Security documents include, for example, identity cards such as identity cards, passports, identification cards, access cards, bank / credit cards,

Health cards, but also driving licenses, visas or documents of value such as banknotes, securities, postage stamps, customs stamps and the like, just to name a few. Also seals and labels for authenticating the authenticity of products or protected by security features against counterfeiting or falsification

Tickets and the like are considered as security documents. Both a material texture, a combination of different materials, a special printing, an introduction of diffractive, refractive, reflective structures and the like can be used as security features. Other security features may be formed, for example, by means of an integrated microchip, a magnetic strip, or other materials having certain physical or chemical properties, such as a luminescent property or

Like.

An essential function of security features is to offer a possibility to determine a genuineness and / or authenticity of the security feature itself as well as of the security document in which the corresponding security feature is integrated. Such a procedure is called verification. Here, the authenticity and / or integrity of the security feature and / or the

Security document checked. In addition to a verification of authenticity and / or

In the integrity of a security document, individual security features, in particular those in which information is stored, can be used to use them to obtain a higher-level verification of the security document or a security document Control of a person associated with the security document. A simple example of this is, for example, one integrated into a passport

Serial number which can be used after a readout to determine, via an alignment with a database in which stolen passports are registered, whether or not the pass which is being verified belongs to the passports reported as stolen. It goes without saying for the expert that even more complex

Verification measures or more complex features for such

Verifications can be used.

Features that can be read out by a human person without the aid of further technical aids from the security document or can be checked directly for their authenticity and authenticity, are referred to as so-called Level-1 security features. Features requiring technical aids for review are referred to as Level 2 features.

Another way to verify security features is to classify them according to mechanisms, mechanisms of action, etc. that are used in the verification. A group of security features may interact with

electromagnetic radiation, in particular light, for example, be checked in the visible wavelength range. A special subgroup of

Security features are security features that interact with light that is dependent on a polarization property of the light. Such security features are hereinafter referred to as polarization-dependent

Security features called. In order to be able to read and check these, it is thus necessary to have available a light source which provides polarized light and / or to use a suitable polarizing filter for verification.

The object of the invention is a verification method for security features, a verification system comprising at least one security element, as well as a

To provide verification methods for its verification, which on the one hand provide a high level of security against adulteration and counterfeiting and on the other hand as simple as possible or verifiable or executable with items and tools that are widespread and easily accessible. According to the invention, such a verification system is provided, on the one hand, by a security document with a security feature, which can be verified by inspection, and which has a light transmission that is dependent on a security document

Polarization property of the incident light is dependent. On the other hand, the verification system comprises a method for verifying this security document, which comprises the steps of: operating a display device, from the display surface of which polarized light emerges, arranging, in particular laying on, a

Security document, which comprises at least one security feature whose transmission properties are dependent on a polarization of the light to be transmitted, in front of the display surface, detecting the light transmitted by the security feature and evaluating the transmitted light and deriving a verification decision.

While the security features in the see-through area of the security document, which exhibits an interaction dependent on the polarization property of the light used for verification, may be designed in a variety of ways, the verification process has in common for all of these differently-designed, see-through, polarization dependent security features separated and independent of the security document to be verified trained display device is used to provide the required for verification polarized light is used. The polarized light is used in normal operation

Display device emitted. The advantage of the verification system or the

Verification method is that commercially available display devices, in particular computer screens, but also screens of portable mobile phones, personal digital assistants, billboards screens, display devices in motor vehicles, video cameras, etc. can be used, the

Image formation by means of a liquid crystal screen (LCD screen) takes place.

Liquid crystal screens are characterized in that these individual pixels have associated liquid crystal cells, which are filled with a liquid crystal, and can be added by applying a voltage in at least two different states. The states differ in that in at least one of the two states, a polarization direction of linearly polarized light at

Passage through the liquid crystal cell is rotated. In the other switching state, a polarization direction of linearly polarized light does not become or at all

rotated different angle amount. The liquid crystal cells are each between Arranged polarizers, which are preferably rotated with respect to the polarization direction, under which they allow light transmission, against each other. In general, the two polarizers are rotated by 90 ° from each other. The light source facing a polarizer generates linearly polarized light, which is rotated in response to the switching state of the liquid crystal cell so that it is the second

Polarizer can pass after passing through the liquid crystal cell or in the other switching state is prevented from passing completely or partially. By way of this, individual pixels can be influenced via the liquid crystal cells assigned to the pixels, which can be controlled individually. In the case of color screens, the individual pixels are assigned a plurality of controllable liquid crystal cells for different base colors, so that any mixing colors can be represented in the color addition for the viewer. The different basic colors can be produced for example by means of color filters.

For the invention described herein, however, it is only critical that leaking light be polarized at each location of a display surface of the display device. For technical reasons, for all or a plurality of liquid crystal cells usually a uniform polarizing filter or at least the same orientation

Used polarizing filter. Therefore, in a preferred embodiment, light emerging from a liquid crystal panel is polarized linearly along a preferential direction regardless of the location of the light exit, hereinafter referred to as

Polarization direction of the exiting light is called. A display device in which the light, regardless of the location of the light exit along the same

Preferred direction is polarized, is referred to as homogeneous with respect to the polarization direction. The exiting light is referred to as homogeneously polarized.

The pole filter direction here is the direction which is parallel to the intersection of the pole filter plane and the plane of polarization of the light emerging from the pole filter. In other words, the polarization direction is the direction under which the light emerging from the polarizing filter is polarized. The polarization direction of the light, which can pass through the pole filter with maximum transmission, is thus oriented parallel to the pole filter direction. Polarized light polarized orthogonally to the polarizing direction can not pass the polarizing filter. In general, a polarizing filter can also be designed to be circular or elliptically polarizing. The Polfilterrichtung can specify a direction of rotation in this case. Parallel means then that the sense of rotation, which dictates the polarizing filter, with the of the circularly polarized light. The terms polarizer, polarizer and polarizer are considered as synonyms.

Preferably, the entire exiting light is polarized in the same way regardless of the place of passage through a polarizing filter or independently of the light exit location from the display device, d. H. one degree of polarization uniform. The degree of polarization is considered to be the proportion of the light polarized along the preferred direction in relation to the total amount of light passing through / exiting.

Is the degree of polarization of the exiting light / light passing independent of the exit from a flat uniformly shaped polarizing filter or from a

Display area of a display device, the polarization is referred to as uniform here.

In a particularly simple embodiment of a security feature, this has only one polarization filter in the viewing area itself. Such a

Polarization filter can be produced, for example, based on a plastic material, such as polyamide, which is stretched along one direction. The polarizing filter, for example, before the production of the document or specifically during card production by lamination and z. B. targeted stretching or targeted train of the material to be or be. In the prior art, various materials are known which linearly polarized light of a

Absorb or greatly attenuate polarization direction and weaken polarized light along a different orientation little or not at all.

Since a degree of attenuation caused by the polarizing filter in the

Is caused by an orientation relative to the orientation along which the light emerging from the display device is polarized is provided in one embodiment of the verification method that an orientation of the security document relative to the display device varies and the transmitted light

Orientation-dependent is evaluated. Preferably, a security document, which has, for example, a sheet-shaped document body in whose main surface the see-through security feature is incorporated, is oriented with the main surface parallel to the display surface and perpendicular to the main surface of the display Security document stationary axis rotated. The main area considered here are the areas which have the largest areal extent of the security document.

If the light emerging from the display surface is 100% linearly polarized along one direction and the polarizing filter incorporated in the see-through security element is ideally formed, the intensity of the transmitted light varies between 100% and 0%. A verification decision can thus be made dependent, for example, on whether, in the case of a rotation of the security document in a plane parallel to the display surface, such is dependent on the relative rotation angle

Transmission variation is detected or not. Even with a tendency of

Document level with respect to the display surface is observable depending on the rotation angle transmission behavior. The rotation angle refers to rotation about an axis oriented perpendicular to the document plane. The

The document level does not necessarily have to be aligned completely parallel to the display area during verification. In a preferred embodiment, a side surface, which has a maximum areal extent, parallel to

Display area aligned. In the case of a security or security document in the form of a card or card, this side surface corresponds to the front or back of the security document.

In another embodiment, the verification decision can be made dependent on how strong the transmission differences are dependent on a

Rotation angle are. This can be used, for example, to check whether the quality of the polarizer in the security feature to be verified corresponds to a quality that is to be found in an authentic security feature. In particular, a difference between the maximum and the minimum transmission can be evaluated.

It is particularly desirable to store information in security documents and to associate this with a security feature in such a way that the information can be read out during a verification of the security element and the information is simultaneously secured by the security feature and its verification. In one embodiment of polarization-dependent see-through security features, this is designed such that this see-through security feature is spatially structured such that different interaction properties exist for different passage positions of a laterally extended see-through feature for light passing vertically through the laterally extended security feature. With unpolarized light, this property can not be perceived, so that a transmission is homogeneous over the laterally extended surface of the security feature. However, if light of one polarization direction is radiated in, this can be at some positions, for example, if the security feature is one or more

Polarizing filters include, but are not nearly attenuated or fully attenuated, but others are partially or completely absorbed, i.

attenuated or completely prevented from transmission. Optical detection thus enables the pattern of the localized arrangement to be different

to detect trained local Polfilterrichtungen and a coded thereto

To read information. A preferred embodiment of a verification method thus provides that the transmitted light is detected spatially resolved and evaluated. Even in such an embodiment, the perceptible information changes during a rotation, as this polarization is varied relative to the individual locally different Polfilterrichtungen. Thus, different positions or regions of the polarization-dependent see-through security feature have different

Light attenuation at different angular positions with respect to

Polarization direction of the light used for verification of the display device.

Such a locally structured polarization dependence can, for example, also be brought about by introducing a so-called phase delay layer in front of a polarization filter. This consists of an anisotropic material, which is different for different polarizations of the light

Propagation properties within the anisotropic material, which can be expressed for example by different refractive indices n for polarization components. The anisotropy can be locally adjusted, for example, in a photo-orientable material. In the production, a local orientation of molecules can be brought about by a light irradiation, which is then permanently fixed. Since light is a transverse wave, the electric field vector oscillates perpendicular to the propagation direction. The direction of oscillation indicates the polarization direction. Each direction of vibration can be considered as a superposition of two orthogonal Describe field vector base vibration states that may have the same frequency but different amplitudes and / or phase angles. Is the

Phase difference equal to zero, one obtains linearly polarized light whose orientation depends on the amplitude ratio. For other phase differences, elliptically or circularly polarized light is obtained. Depending on the size of the induced

Refractive index difference and a thickness of the retardation layer and a direction of incidence relative to an optical axis associated with the anisotropy occurs depending on the wavelength, a change in the polarization property for linearly polarized light. The general rule is as follows: Δφ = (2π / λ) · And, where Δφ causes the change in the relative phase between the two mutually orthogonally oscillating electric field vector base vibrations when passing perpendicular to the optical axis through a layer of thickness d for light of wavelength λ, in which the refractive index difference An = n _e - n ₀ between the ordinary (o) and extraordinary propagation directions (e) in the locally oriented material of the

Delay layer indicates. At a layer thickness of 14 μηι and a

Refractive index difference of An = 0.01, for example, at a wavelength of 560 nm, a phase shift of π / 2 occurs between the field vector base oscillations. Linearly polarized light becomes circularly polarized light. So is a locally structured delay layer in front of an unstructured polarizer in the

Transparent security feature formed so the information stored in the local structure of the delay layer information is not visible, if in the

Retard layer unpolarized light enters and then exits through the polarizing filter of the security feature. Even if the light is first polarized by the polarizing filter and then passes through the patterned retardation layer, it is not visible to a human observer because the polarization change occurring in the retardation layer does not cause any intensity attenuation. Occurs, however, by the retardation layer, for example, linearly polarized light, which from the

Display surface exits, and after passing through the retarder layer through the polarizing filter of the security feature, so in the structured

Delay layer stored information visible. Depending on the patterning of the retardation layer, the light emerging from the display device, which has the same direction of polarization at the exit independently of the exit position, is locally changed differently with respect to the polarization, so that, depending on this change, portions of the light at the retardation layer

Subordinated polarizing filter of the security feature are absorbed, so that As a result, noticeable intensity differences occur depending on the local structuring of the delay layer.

If a security document with a security feature designed in this way is arranged in front of the display device such that the polarized light emerging from the display device first passes through the polarization filter and only then through the delay layer, then the information stored therein is again not visible. Depending on the orientation of the polarizing filter relative to the polarization direction of the exiting light, i. the relative orientation of the document before the

Display surface in a plane parallel to the display surface, as described above over the entire surface of the security feature is an orientation-dependent

Observe intensity variation when performing a rotation.

If, alternatively or additionally, the polarization filter of the security feature is structured in a location-dependent manner, regardless of whether the polarization filter or the delay layer faces the display during the verification, in both cases perceptible local intensity variations of the light emerging from the display surface.

Since the change of polarization state in the retardation layer

Depending on the orientation of the pole filter direction of the polarization filter of the security feature relative to the polarization direction of the light exiting from the display surface, security features can also be realized which are wavelength-dependent. With a suitable choice of the refractive index difference and the layer thickness of the retardation layer is a difference in the

Delay layer caused polarization direction rotation for the ordinary beam over the extraordinary beam for one wavelength π and for another wavelength 2π. In such a situation, if the optical axis is oriented parallel to the surface of the retardation layer and perpendicular to the irradiation direction, the polarization direction for light whose polarization direction is at 45 ° to the optical axis for which one wavelength is rotated by 90 ° the other by 180 °. Depending on whether the pole filter direction of the polarizing filter is oriented parallel or at 90 ° with respect to the polarization direction of the light emerging from the display surface, light of one or the other wavelength can pass through the polarization filter of the security feature. A turn of the Security feature relative to the polarization direction of the light emerging from the display surface thus leads to a clearly perceptible effect. With a suitable choice of the layer thickness and the refractive index difference, color changes from ocher yellow to blue, turquoise to red, violet to green, red to green, etc. can be realized.

If the display device emits light of different wavelengths which have a spectral distance which is considerable for the physiological perception in the visible spectrum, for example light in the blue and red wavelength range at the same time, it is possible that with a suitable choice of one

Refractive index difference for the propagation of the ordinary and the

extraordinary beam in an anisotropic medium and a corresponding choice of a layer thickness of the polarization vector of a color component, for. B. the blue light, is changed more than that of the other color component, z-B. of the red light. If this angle difference is 90 °, then the one color component can exit, for example, unhindered through the polarization filter of the security feature. The other, however, is completely prevented from transmitting. Will now be the security document with the security feature in the plane of

Polarization filter rotated by 90 °, so the corresponding other color component can pass through the polarization filter unhindered. Now the first color component at a passage is completely prevented.

About a suitable time-varying control of the display area, the one

Color change causes a local change of the perceived color image can be achieved analogous to a known from the prior art tilting image without the security feature is moved or rotated.

By means of a suitable spatially varied actuation of the display surface, which at the same time causes different color areas on the display surface, a local change in the perceived color image can be achieved when the security feature is moved parallel to the display surface over the different color ranges. (This is also an effect analogous to the effect known from the prior art in tilted images.)

This effect can also be achieved without local structuring of the retardation layer. A suitable control of the display surface can be achieved that this light in the blue and red wavelength range and no or almost no light in intervening green wavelength range emits. In color displays that usually operate according to the red-green-blue (RGB) principle, which produce the physiologically perceptible color through a color addition, such becomes

Light emission achieved, for example, by a purple or magenta surface is displayed on the display surface. For a verification of such

Security element is thus with suitable flat color representation on the

Display surface changes the perceived for the human viewer color by the see-through security feature in front of the display surface is arranged. Moreover, a change in color perception is dependent on the rotation angle of the rotation in the plane of the polarizing filter of the

Security feature.

If the color representation on the display device is changed, this also influences the perceptible effect of the wavelength-dependent polarization rotation in the retardation layer. If, for example, a color is displayed on the display surface that is represented by a monochromatic or almost monochromatic color

Light emission is caused, so found in the arrangement of the

Security document in front of the display area and a comparison of the perceived colors without and with interposed security feature no color change taking place. During the rotation of the polarizing filter in its laterally extended plane, although an intensity fluctuation of the transmitted light is perceptible as explained above several times, but no or no significant color change

imperceptible.

Another possible security and verification system is one

Security feature realized in which both a delay layer and a polarizing filter locally modified or each formed in the form of a grid. If the grids are slightly different, the result is a verification moire pattern. Without polarized radiation, such an effect is unobservable and not even with an arrangement of the security feature in front of the display device, in which the polarizing filter faces the display surface. Moire patterns show one

Viewing angle dependence and also a rotation dependence, if the security feature in the plane of the polarizer or the structured polarizing filter is rotated. In yet another embodiment of a security and verification system, a security feature is used, which is a switchable, the

Polarization property of the passing light influencing element comprises. For example, one or more liquid crystal cells may be integrated into a see-through feature. On one side of the cells a polarizing filter is placed. Depending on the switching state is thus a change in the polarization direction by the

Liquid crystal cells causes. Depending on the orientation of the pole filter relative to the polarization direction of the radiation emerging from the display surface, a maximum transmission in one switching state and a minimum transmission in another switching state can be achieved. About a turn of the

Security feature in the plane of the polarizer of the security feature, the transmission property for the two switching states can also be changed. If a plurality of switchable polarization features, for example a plurality of liquid crystal cells, are integrated into the security feature, then these can be designed differently, so that, for example, a cell in the de-energized state does not change the security

Polarization direction of the incoming polarized light causes and another causes a rotation of the polarization vector by 90 °. In such a case, in the case of an arrangement of the security feature in front of the display surface, information can be recognized that the light passing through one of the two cells and the polarizing filter has a maximum transmission and the light passing through the other cell and the downstream polarizing filter has a minimal transmission having. If both cells are energized at the same time, the transmission behavior assigned to the cells changes in each case. If, in addition, a structuring of the pole filter is carried out as a function of the location in the plane of the pole filter, then a local change in the transmission behavior can also result in a uniform change in current flow

Liquid crystal cell can be achieved. Likewise, combinations are conceivable in which the cells have different and the associated polarizing filters have locally different polarization directions oriented relative to each other. If the cells can be switched over transparent electrodes assigned to the individual cells, individual patterns can also be realized by switching analogously to an LCD display. These are only observable when polarized light enters the cells and the polarizing filter is located on the viewing side of the cells.

Yet another verification behavior show polarization-dependent

Security features incorporating a polarization-dependent hologram. Is in For example, if the security feature integrates a polarization transmission hologram, the diffraction behavior of the light or of a spectral component (one or more wavelengths) of the light is polarization-dependent. Depending on the rotation of the hologram relative to the polarization direction of the

Display surface of escaping light is the diffraction behavior of

Polarization hologram changed. With a rotation of 180 ° thus changes the perceptible information.

On the other hand, when a polarization reflection hologram is used, there is absorption / reflection for a wavelength and a polarization of the incident polarization light in the hologram. If light of this wavelength is emitted by the display device in a predetermined polarization direction, there is a minimum transmission of this wavelength and polarization for an alignment of the hologram. Light of a corresponding color is thus due to the hologram due to

"Reflection / Diffraction" prevented a passage, so at a

Reviewing a color change due to the "blocking" of this wavelength is observable. The condition is that the display device exactly this

Wavelength also emitted.

In one embodiment of the value or security document, this includes

Security element a polarization-dependent hologram.

In one embodiment, the polarization-dependent hologram is one

Transmission hologram.

Other embodiments provide that the card body additionally or alternatively comprises a retardation layer which changes, in particular rotates, a polarization direction of the light passing through in at least one wavelength range.

In one embodiment, the delay layer is spatially structured so that the polarization change is locally different.

The retardation layer may be formed of a photo-orientable material. Yet another embodiment provides that the card body additionally or alternatively comprises a switchable, a transmission exhibiting optical element having at least two switching states, wherein a polarization of the transmitted radiation is influenced differently in the two switching states.

An embodiment provides that the optical element at least one

Liquid crystal cell comprises, which by applying a voltage their

Polarization property changes.

A further development provides that the document body comprises a switchable energy source, for example a photovoltaic element with a switch or a piezoelectric crystal, for providing the voltage to the at least one liquid crystal cell.

This provides a high degree of independence from external sources

Tension reached. Other conceivable energy sources are contactless energy sources, e.g. obtained by an inductive or capacitive coupling with a reader energy. On the document an array of antennas, e.g. a dipole and / or a coil and / or capacitive surfaces may be used. The energy can be injected through a POS system, RFI D ISO 14443 reader or NFC (Near Field Communication) cell phone (NFC).

The invention is based on preferred embodiments below

Reference to a drawing explained in more detail. Hereby show:

Fig. 1 is a schematic representation of a verification system with a in

Review verifiable security feature;

Fig. 2a is a schematic view of a security document with a

See-through safety feature in a first orientation relative to the display area of a display device;

2b shows a schematic representation of the security document according to FIG. 2a in a changed orientation of the document relative to the display surface of the display device; Fig. 3 is a schematic sectional view of an embodiment of a

Security document; a further schematic representation of a sectional view of a

Security document;

Fig. 5 is yet another view of another embodiment of a

Security document; a perspective schematic representation of a

Security document;

Fig. 7a - 7c views of the security document of FIG. 6 under different

Orientations relative to the display area of a display device; a schematic representation of a security document, which has a delay layer and a polarizing filter, for explaining a polarization-dependent color effect;

9a, 9b schematic representation of a polarization hologram having

See-through safety feature in a first position (9a) and in a second position (9b) relative to the polarization direction of the light of a display device;

10a-10e are schematic illustrations for illustrating the

Intensity dependence on the rotation of a security feature, with a structured delay layer; a matrix by means of which an influence of anisotropic

Retarder layer to light of different wavelengths (colors) in cooperation with a polarization filter fixedly coupled to the retardation layer depending on an orientation relative to the polarization of the incident light; Fig. 12 is a schematic diagram for explaining a security feature with a dichroic polarizer;

Fig. 13 is a schematic representation for explaining a security feature similar to that of Fig. 1 1, wherein the polarizer is not

wavelength selective acts; and

14 shows a schematic illustration of a security element in which a linear polarizer is arranged between two anisotropic, structured delay layers.

FIG. 1 shows a schematic representation of a verification system 1 for a security feature 2 that can be verified by inspection. The verification system includes a

Display device 3 with a display surface 4, from which during operation of the

Display device light 5 exits, which at least locally defined

Having polarization property. Preferably, the light emerging from the display surface 4 has the same polarization property over the entire lateral extent of the display surface 4, at least for light of the same wavelength. Particularly preferred are display devices in which the light has the same uniform polarization property regardless of the wavelength of the emitted light. Preferably, the exiting light is homogeneous and uniformly polarized over at least one wavelength over the entire display area.

Display devices 3 which in operation emit light of a predetermined polarization property are, for example, liquid crystal displays which, for example, comprise a viewing side facing uniformly shaped polarizer defining linearly polarized light of a polarization direction 6 of the exiting light 5. A color or wavelength of the emergent light is determined by an information displayed. At different positions, light of different intensity and wavelength can thus escape. The information representation can be controlled via a personal computer (PC) 18, for example.

The security feature 2 has a transmission property for light, which is dependent on a polarization property of the light. This means that at least locally over the lateral extent of the security feature 2 in a surface 10, from which exits the transmitted light 5 ', the transmission depending on a

Polarization property of incident on the security document light 5 is. The security feature 2 is preferably integrated in a security document 11. Due to the transmission characteristic of the security feature 2, this forms in the

Security Document 1 1 a so-called see-through window 13. This see-through window 13 may extend over a laterally limited area of a surface 12 of the

A delineation of the see-through window 13, which is formed by the security feature 2, is perceivable only in the cases visually independent of the verification of the security feature 2, when the security document 1 1 along a peripheral edge 14 of the see-through window 13 is designed opaque for the light used for verification or this is marked graphically.

It is also possible to design the see-through window so that it is located on one of the surface 12 of the surface for verification

Security document or security feature 2 overprinted with translucent colors or other, a certain transparency having color filters is hidden. It is essential that the security feature 2 in the see-through window 13, which is formed by the security feature 2, shows a dependent on the polarization of the light property. Embodiments are preferred which show a transmission which depends on the polarization direction of the light which occurs. This means that there must be at least two different polarization properties or states of a polarization property that result in a different transmission of light of the corresponding polarization properties or states of the polarization property.

In the verification of a polarization-dependent transmission having a security feature thus the transmitted light 5 'by a

Detection device 20, which may be, for example, an eye 21 of a human person detected. The detection device can also be a digital camera, the detected image of which is formed by an evaluation device, which is preferably formed by hardware and / or software, for example in a mobile telephone with a processor unit. In a very simple embodiment, the security feature 2 is designed such that it only changes the polarization state (the polarization property) of the transmitted transmitted light 5 'with respect to the polarization state (the polarization property) of the incident light and a polarization measuring device is used for the subsequent verification of the polarization property on the transmitted light.

If, for example, the security feature has an optically anisotropic material, which is formed, for example, in the form of a λ / 4 plate, then linearly polarized light, which impinges on the security feature and is transmitted through it, is converted into circularly polarized light. The emitted transmitted light can then be detected by means of a suitable polarizer and an optical filter

Detection device to be checked to see whether the emerging light has a corresponding circular polarization or not. Such a polarizing filter is designed such that it transmits only correspondingly circularly polarized light.

Depending on the observed transmission through the polarizing filter, it can thus be determined whether the see-through safety feature has the expected polarization characteristic and is verified on the basis of the examination result.

However, as already mentioned, embodiments in which a polarizing filter is integrated into the security feature 2 are particularly preferred. In a particularly simple embodiment of the security feature 2, this is designed as a linear polarizing filter 31. As a linear polarizing filter, here is referred to a polarizing filter which allows light with a linear polarization to pass along a polarization direction 6 when a polarizing filter orientation is oriented parallel to the polarization direction of the light. If the polarization direction of the light and the polarization filter direction of the polarizer are oriented orthogonal to one another, transmission is completely suppressed in the case of an ideal polarizing filter.

In Fig. 2a is in front of a display device 3 with a display surface 4 a

Security document 1 1 arranged with a see-through window 13, which forms a security feature 2. The security feature 2 is designed such that it has a polarizing filter, for example a linear polarizing filter 31, with a polarizing filter 32. The display device emits polarized light. The polarization direction 6 of the light emerging from the display surface 4 is indicated by a hatching direction of Display surface 4 shown. The pole filter direction 32, which is coupled to the orientation of the security feature 2, is indicated by a hatching of the see-through window 13 or pole filter 31, which forms the security feature 2. In the orientation of the security feature 2, in which the polarizing filter 31 and the

Security document 1 1 are oriented with respect to their lateral area parallel to the display surface 4, occurs when viewed in review by the

See-through window 13 emitted from the display surface 4 in operation polarized light 5 through the security feature 2 therethrough, provided that the Polfilterrichtung 32 and the polarization direction 6 of the light 5 are oriented in parallel. If the security document 11 is now rotated about an axis 33 which is oriented perpendicular to the surface 12 of the security document or of the security feature 2, a situation is obtained as shown in FIG. 2b.

The Polfilterrichtung 32 and the polarization direction 6 of the light are oriented perpendicular to each other, so that no light passes through the polarizing filter 31, which forms the security feature 2. For verification, therefore, the transmission

orientation-dependent evaluated by a rotational orientation of the security feature 2. If a polarizing filter is formed in the security feature 2, then the transmission behavior shown in FIGS. 2a and 2b can be observed as a function of the angle of rotation. In angular positions between the angular position, which is shown in Fig. 2a, and the angular position, which is shown in Fig. 2b, is a

attenuated transmission depending on the angle of rotation about the axis 33 to observe or detect.

When illuminated with unpolarized light, when viewed in phantom, there is no angular dependence of rotation about axis 33 which is perpendicular to the axis

Surface 12 of the security document 1 1 is oriented to observe. In the illustrated embodiment of FIGS. 2a and 2b, in which the security feature 2 is formed only as a polarizing filter 31, it is also irrelevant whether the in Fig. 2a the

Viewer facing surface 12 or a rear surface 15 of the

Display device 3 faces.

In further embodiments (not shown), it is possible to make the see-through window so that either the polarizer is locally structured, for example, by the layer forming the polarizing filter is locally perforated and thus has breakthroughs on where no Polfilterwirkung occurs, or the see-through window is configured, a plurality of different polarization directions relative to each other

To include polarizer elements, which are arranged laterally side by side in the see-through area. Individual local areas along the lateral extent of the

Security feature then have different transmissions depending on the angle of rotation about an axis perpendicular to the surface of the security feature. At the points where the uniform polarizing filter is perforated, there is no

To observe angular dependence and in each position a transmission too

observe. At those positions where the polarizing filter is not modified, a behavior analogous to that according to FIGS. 2a and 2b can be observed. In the embodiment in which a plurality of different pole filter directions having laterally juxtaposed Polfilterelemente are formed, these each have a behavior analogous to that described in connection with FIGS. 2a and 2b polarizer. However, since the individual Polfilterrichtungen the Polfilterelemente have different directions, are for a variety of angular positions, possibly for all

Angular positions, the security feature at different positions laterally distributed over the security feature to observe or capture different transmission values.

In one embodiment, there are two sets of poling filter elements. The

Polar filter elements of a group each have all the same pole filter direction. The polarization direction of the polarization filters of one group is orthogonal to the polarization direction of the polarization filters of the other group. In a security feature designed in this way, there is a uniform light transmission in all polarizing filter elements when the

Polarization direction of the light in each case at 45 ° to the Polfilterrichtungen the

Polfilterelemente stands. For all other orientations, the polarizing filter elements of one polarizing filter direction (group) have a first transmittance, the orthogonally oriented polarizing filter elements (of the other group) a second one of the first

Transmission deviating transmission.

FIG. 3 shows a schematic layer structure of a security document 11 with a polarization-dependent security feature 2 designed differently. In the schematic representation, the security feature 2 extends over the entire lateral extent 60 of the security document 11. The security document 1 1 or the security feature 2 is formed from different layers 51 -55. The Security feature 2 has a viewing side 56 provided for the verification and a radiation side 57 arranged on the opposite side. From the irradiation side 57 to the viewing side 56, the layers 51 to 55 are formed as follows in terms of their function and nature. The layers 51, 53 and 55, ie a viewing side facing layer 55, a middle layer 53 and the Einstrahlseite 57 facing layer 51, are formed as transparent, preferably a wavelength-independent transmission having layers.

For example, these may be non-colored polycarbonate layers. Between the irradiation side 57 facing the transparent layer 51 and the middle transparent layer 53, an optically anisotropic, birefringent layer 52 is arranged. In this birefringent layer 52, the light polarized along different axes propagates at a different propagation velocity. This leads u.a. In addition, such a layer has a state of polarization passing through it

can change light passing through. For example, linearly polarized light can be converted to circular or elliptically polarized light. If appropriate

Design can also be caused by a rotation of the polarization axis of the transmitted light. With a suitable choice of the layer thickness d of the birefringent layer 52, which is also referred to as retardation layer 58, it can be achieved, with a suitable choice of anisotropy, that the retardation layer 58 acts as λ / 2 plate for a given wavelength λ _0, for example. An optical axis 59 of the birefringent layer 52 is in this case oriented so that it is oriented parallel to the lateral extent of the birefringent layer. For the verification used light 5 then occurs preferably perpendicular to the optical axis 59 through the entrance side 57 in the security feature 2 a. Depending on an angle α a

Polarization direction relative to the optical axis finds a rotation of

Polarization direction by a rotation angle ß = 2a instead, which is twice the angle α between the polarization direction 6 of the incident light and the optical axis 59 corresponds. Light 5 polarized at a = 45 ° relative to the optical axis 59 is thus rotated in the anisotropic birefringent layer 52 by β = 90 ° or β = π / 2.

Via the polarizing filter 31, which is formed in the layer 54, the polarization of the passage through the anisotropic, birefringent layer 52 with respect to the

Polarization direction 6 'rotated light 5 are checked. Depending on one

Rotation of the security element 2 about an axis 33 perpendicular to the Extension directions of the birefringent layer 52 and the pole filter 31, thus an angle-dependent variation of the transmission can be observed.

FIG. 4 shows a further embodiment in which only one see-through window 13 is formed in the security document 1 1, which is shown in FIG

Embodiment consists only of a birefringent layer 52 and a trained as a polarizing filter layer 54.

FIG. 5 diagrammatically shows a further embodiment of a security document with a transmission-dependent security feature 2, in which the anisotropic delay layer 58 is locally structured. Along the lateral extension of the security feature 2 different areas are formed differently in terms of their anisotropy. Light passing through the individual regions 61 i62 _n is thus influenced differently with regard to its polarization properties. On the downstream polarizer 31 thus different intensities can be observed, which of the respective locally varied configuration of

Depend on delay layer 58. The individual areas can be in others

Embodiments be designed differently. For example, these may differ in all or in groups with respect to their anisotropy. It should be noted at this point that both the strength of the anisotropy and the orientation relative to a coordinate system associated with the security document can be selected individually for the individual areas.

A locally different optical anisotropy both in terms of the strength of the anisotropy, as well as an establishment of the optical axis can in photoorientierbaren materials, as known from the prior art, by a

Laser irradiation be set in a wide range. This makes it possible in the manufacturing process of the security feature information, in particular

individualizing or personalizing information to be stored in the delay layer which can be read out upon verification of the security document when placed in front of a display device which emits polarized light.

It is understood that it is also possible, as indicated above, to also laterally structure the polarizer with respect to different orientation directions. Also By way of this information, in particular individualizing or personalizing information can be stored in the security feature. As individualizing and / or personalizing information, such information is considered to be a security feature in relation to other security features individually

distinguishable. As personalizing such information is considered, which can be assigned to a person who is assigned to the security feature or the document which is provided with the security feature.

In Fig. 6 is a schematic security document with a

Transparency security feature 2 shown schematically isometric. In one of the inlet side 57 facing region of the security feature 2 is a

Retarder layer 58 is formed, the two areas 61, 62 which cause a different change in the polarization of incoming light. At the viewing side 56 facing portion of the security feature 2, a linear polarizing filter 31 is formed.

The verification of that shown in FIG. 6 is to be explained with reference to FIGS. 7a to 7c

Security feature exemplified. In the position shown in FIG. 7 a, the pole filter direction 32 of the security feature 2 is orthogonal to the polarization direction

Polarization direction 6 of emerging from the display surface 4 light 5 oriented. In the region 61, no rotation of the polarization direction is effected in the retardation layer, so that the light of the region 61 exiting the retardation layer is polarized perpendicular to the polarization filter direction and this region 61 is perceived as transparent in the dark. By contrast, the region 62 causes a rotation of the polarization direction by 90 ° so that the light passing through the retardation layer in the region 62 is now oriented parallel to the polarizing filter 31 of the security feature 2, so that the region 62 is perceived as bright.

In the position shown in FIG. 7 b, the different regions 61, 62 of the retardation layer cause the light passing through to be linearly polarized at 45 ° with respect to the polarization filter direction of the polarizer 31. Both areas 61, 62 are thus as bright and opposite to a maximum

Transmission darkened perceived. In the third position, which is shown in FIG. 7c, the light passing through the region 61 is now parallel to the pole filter direction 32 of the polarizer 31 of FIG

Security feature 2 oriented so that this area 61 is perceived bright. The light passing through the region 62 of the retardation layer is rotated with respect to its polarization direction so that it is now perpendicular to the polarization direction

Polfilterrichtung 32 of the pole filter 31 is oriented and this can not happen. As a result, the area 62 is perceived as darkened.

With a suitable embodiment of the anisotropy can be achieved beyond that light of different wavelengths significantly different in terms of

Polarization direction is changed. It can be achieved for light of one color (wavelength) one polarization direction rotation by 90 ° and for light of another color (wavelength) to cause a circular or elliptical polarization or to achieve that no or a negligible rotation of the polarization occurs. When viewing the see-through security feature, which again has a linear polarizing filter on the side facing the observer, a is shown

Color change when the document is rotated about an axis perpendicular to the surface of the security document. By means of a local structuring of the retardation layer and / or of the polarizing filter as well as by means of translucent overprinting, it is thus possible to produce a variety of patterns which, when rotated in front of the screen

reveal different information. For this purpose, a differently colored image is displayed on the display surface of the display device, more color effects can be observed depending on an orientation or depending on the color shown. Thus, different verification methods can be used, which include a spatially resolved, orientation-resolved and frequency-resolved or wavelength-resolved and / or a color perception taking into account evaluation of the transmitted radiation. Over a comparison with specifications can such a

Verification decision are derived.

In Fig. 8, a security document 1 1 is shown schematically, which is a

Security feature 2 in the form of a see-through window 13 which extends over the entire lateral extent 60 of the security document. The

Security feature 2 includes an anisotropic retardation layer 58 which is not laterally structured. In addition, the security feature 2 comprises a polarizing filter 31. The Dimensions and dimensions of the individual layers and elements are not realistic and are chosen here for illustrative purposes only.

From a display surface 4 of a display device 3 emerges light 5, which is linearly polarized. The polarization direction 6 is perpendicular to the plane of the drawing. The display surface 4 is shown to the right rotated by 90 ° schematically. The

Polarization direction 6 of the light can be clearly seen, which emerges in this representation in the direction of the viewer to the drawing plane. The light 5, as shown in the left half, enters the retardation layer 58 of the security feature 2. The optical axis 59 of the retardation layer 58 is oriented parallel to the entrance side 57. The entrance side 57 into the retardation layer 58 is schematically shown rotated right again by 90 °. It can be seen that the polarization direction 6 has an angle of 45 ° with respect to the polarization axis 59. When passing through the retardation layer, the light 5 is wavelength-dependent with respect to its

Polarization direction rotated. Here, in the exemplary embodiment illustrated, it is assumed that the light 5 comprises portions having a wavelength which produces a yellow color impression, and comprises portions whose wavelength causes a blue color impression in the observer. Both parts are polarized on entering the retardation layer along the same spatial direction, which is indicated by the adjustment of the words yellow, blue behind the reference numerals of the polarization direction 6.

With a suitable choice of the layer thickness d and the Anisotropiestärke and the

Anisotropierichtung of the material, the polarization direction of the blue portion of the light, for example, by 1 80 °, the polarization direction of the yellow portion of the light 5 but only rotated by 90 ° when passing through the retardation layer 58. This is schematically shown again right where the different

Polarization directions 6 _ge ib, 6biau and the optical axis 59 are shown schematically at the exit from the retardation layer 58. The polarization direction of the blue light component 6 _'b iau is indicated by a dot-and-double-headed arrow, whereas the polarization direction 6' _ge ib of the yellow portion double arrow is shown by a dash-dot-dot. Furthermore, the Polfilterrichtung 32 of the subsequent polarization filter 31 is shown by a double arrow. The Polfilterrichtung is parallel to the polarization direction 6 _b i _au , _ge ib, with the light 5 originally exits the display surface 4. It follows that only the blue portion of the from Retardation layer 58 of the exiting light can pass through the polarizing filter, while the proportion of the yellow light is absorbed by the polarizer 31.

From the see-through window 13, which represents the security feature 2, thus exits only blue light. If, however, the security document is rotated by 90 ° about the axis 33 oriented perpendicular to the display surface and the surface 12 of the security document, the color of the emerging light changes. On the right, the corresponding levels for this state are shown in dashed lines, the individual areas are also slightly offset from each other for reasons of clarity. Again, the incoming light is oriented 45 ° to the polarization direction. After exiting the retardation layer 58 are again

Polarization directions 6 ' _ge ib of the yellow light by 90 ° and 6' _b iau of the blue light by 180 ° with respect to their original polarization direction 6 _b iau, _g eib rotated. However, since the Polfilterrichtung 32 of the polarizing filter 31 rotates with the rotation of the document, now the polarization direction 6 'yellow _{ge of} the yellow light is oriented parallel to Polfilterrichtung 32 of the polarizing filter 31, so that the yellow light exits the document and the blue light is absorbed. This exemplary

Embodiment shows that rotation-dependent color effects can be used in the verification. It is understood that a lateral structuring of the

Delay layer and / or the polarizing filter can be made. To explain the principle of the security feature and not to complicate this explanation, is here for reasons of clarity on a lateral

Structuring the delay layer and the polarization filter omitted. In some embodiments, the retardation layer is lateral to storage

Structured information. In other embodiments, the polarization filter is laterally structured. In yet other embodiments, the retardation layer and the polarizer are laterally patterned. In addition, printed translucent or opaque color layers in the security document can also be formed in the area of the security feature 2 in order to realize different color effects or color patterns, depending on the orientation of the security feature relative to the polarization direction of the incoming light. Since the viewer perceived color of the

Screen is determined by a color addition of the light components, the perceived color changes in addition to the color, which perceives the user in a direct viewing of the display area. In FIGS. 9a and 9b, the mode of operation of a polarization-dependent hologram is shown by way of example. From the display surface 4 of the display device 3 occurs linearly polarized light 5 and meets a trained as a see-through window 13

Security feature 2 of a security document 1 1. In the security feature 2, a polarization-dependent reflection hologram 72 is formed, which reflects light of a wavelength and a specific polarization direction in an elliptically formed region 71. If the wavelength or the polarization do not match the given wavelength and polarization, the hologram transmits this light 5 '. This situation is shown in Fig. 9a.

If the security document 1 1 and hereby the security feature 2 located in the see-through window 13 are rotated about an axis 33 which is oriented perpendicular to the surface 12 of the security document 11, the polarization direction 6 of the light 5 changes relative to the hologram 72 9b illustrates the situation in which the polarization direction 6 of the light 5 emerging from the display surface 4 coincides with the polarization direction at which the reflection hologram 72 in the elliptical region 71 reflects the incident light 5 " If, on the other hand, unpolarized light strikes the security feature 2, then, when viewed in transmitted light, even with a rotation about the axis 33 which is perpendicular to the surface 12 of the security document, no intensity fluctuations due to the integrated hologram are perceptible. The hologram can auc h be laterally structured so that the polarization dependence of the hologram is different at different locations (positions).

An intensity dependency of a security feature 2 consisting of four regions 61 - 64 for different orientations relative to the polarization direction of the display surface of a display device will be described on the basis of FIGS. 10 a to 10 e

Exiting light will be explained. In Fig. 10a, the individual areas, which for reasons of illustration have different geometric shapes, are shown schematically. A cross 81 shows the anisotropy and its orientation relative to a coordinate system 91. When traversing the elliptical region 61 perpendicular to the plane of the drawing, in the case of light of a wavelength λ, a phase shift of half a wavelength (λ / 2) between the two orthogonal to each other polarized light beam proportions causes. The anisotropy axis coincides with an X direction 92 of the coordinate system 91.

The triangular-shaped area also causes a phase shift by half the wavelength in the passage of mutually orthogonally polarized beams. In this area, the anisotropy axis is 22 ° to the X direction 92 of the

Coordinate system 91 twisted.

The square region 63 also causes a phase shift of half the wavelength. The anisotropy axis is in this case rotated by 45 ° with respect to the X direction 92 of the coordinate system 91.

The cross-shaped region 64 has weaker anisotropy, with only a phase shift of λ / 4, i. 1/4 of the wavelength in the passage of radiation traveling along the Z-direction of the coordinate system, i. perpendicular to

Drawing plane, propagates, occurs between light which is polarized orthogonal to each other. The anisotropy direction is rotated by 0 ° with respect to the X direction 92 of the coordinate system 91.

For all regions 61-64, the data relate to the same wavelength λ, which has been adapted to the material.

FIGS. 10b to 10e show a security feature 2 which is composed of the four regions 61 - 64 according to FIG. 10a. The areas 61-64 each have the anisotropy strength and anisotropy direction as the corresponding areas in FIG. 10a with respect to the coordinate system 91 associated with the security document. The hatch density of the areas 61-64 in Figs. 10b-10e respectively indicates the observed intensity for the wavelength λ of light propagating along the Z-direction 104 of a coordinate system 101 stationary with respect to the display area. In general, for FIGS. 10 to 14, the lower the coating density, the higher the intensity. The polarization of the light emerging from the display surface is linearly polarized parallel to the X-axis 102. The linearly polarized light thus hits the

Security feature 2 and traverses the different areas 61-64, which have the indicated isotropy. Subsequently, this occurs in terms of

Polarization state optionally modified light by a in the Security feature integrated polarizing filter 31. The polarization direction of the polarization filter 31 is oriented parallel to the Y axis 93 of the coordinate system 91, which is stationary with respect to the security feature 2. Thus, in FIG. 10b, the coordinate systems 91 and 101 are aligned with each other such that the X-axes 92 and 102, the Y-axes 93 and 103, and the Z-axes 94 and 104 are parallel to each other. FIGS. 10c to 10e show the viewing situations in which the security feature in each case extends in a plane parallel to the display area by one

indicated angle α with respect to the Z-axis 104 of the coordinate associated with the display surface coordinate system 101 is rotated. This means that the X-axis 92 and the Y-axis 93 with respect to the X-axis 102 and the Y-axis 103 are each rotated by the indicated angle α with respect to the still parallel Z-axes 94 and 104 against each other are. It should be noted that with the areas 61-64 of the security feature 2, the polarization filter 31 of the security feature 2 coupled to the areas also rotates, and thus the pole filter direction 32 relative to the polarization direction 6 of the light emerging from the display area Angle α is twisted or twisted. It can be clearly seen that a security element which is structurally structured with respect to the anisotropy and has a surface uniformly formed polarizing filter has different intensities relative to the polarization direction of the light emitted by the display surface as a function of the relative orientation of the polarizer of the security document. The geometrical shapes chosen here are chosen here for illustrative purposes only. Of course, the regions having different isotropy may all or in groups have a similar or identical geometry.

In Fig. 1 1 is shown schematically in a matrix, as an anisotropic material for different wavelengths and at different orientations of

Security feature relative to the polarization direction of the incident radiation of the display area changed. In different columns of the matrix, the rotation of the security feature with respect to the polarization direction of the incident light emitted by the display surface is shown. The four columns show the rotations 0 °, 22 °, 45 ° and 90 °. In the different lines of the matrix is the

Change in polarization state depending on the rotation for

indicated different wavelengths or colors of the light. The individual lines show the effect on red light (top line), green light and blue light among each other and in the last line the sum color resulting from color addition. The anisotropy direction is of course the same for all wavelengths. When the security feature is rotated by 0 ° with respect to the polarization direction of the incident light, the anisotropy direction has an angle of 45 ° with respect to the direction of polarization of the incident light. For red light, a passage through the retardation layer causes a phase shift of one fourth of the

Wavelength (λ 1/4). The passage of green light causes a phase shift of half the wavelength (λ 1/2). Finally, for blue light, the retardation layer causes a phase shift corresponding to the wavelength of the blue light. To illustrate, the anisotropy and the anisotropy direction are schematically indicated in each matrix entry via a cross 81. In addition, in the

Anisotripiekreuz 81 of the polarization state 6 of the light emitted by the display (solid arrow), the after passing through the retardation layer resulting polarization state 6 '(dashed arrow) and the polarization direction 32 of the polarizer (dotted arrow) indicated. In addition, each matrix entry also contains a field which indicates the rotation with respect to the direction of polarization of the incident light via its orientation and additionally indicates an intensity for the corresponding color or wavelength via a barrier density.

While in the case of red light, the linearly polarized light at a rotation of 0 ° in circularly polarized 6 'light with a first direction of rotation 7 with respect to

Polarization state is changed, the polarization state 6 'of this light at a rotation of 22 ° elliptical. If the security feature is rotated by 45 °, the anisotropy direction coincides with the direction of the linear polarization 6, so that no change of the polarization state 6 'is caused by the retardation layer. When rotated by 90 °, the linearly polarized incident red light is also circularly polarized, but with a second direction of rotation 8, which is opposite to the first direction of rotation 7. The corresponding resulting intensities are indicated by the hatching.

For green light, the situation is different. When rotated by 0 °, the polarization direction of the incident light is rotated by 90 °. Will that be

Security feature twisted by 22 °, so enters a greater rotation. The exiting light, however, remains linearly polarized. As with the red light, the direction of polarization changes in the orientation of 45 ° when passing through the

Delay layer not. However, since the polarization filter with the As the security feature rotates, the intensity portion of the green light that can pass the polarizing filter decreases. At a rotation of 90 °, the

Polarization direction of the light rotated by 90 °. However, since the polarizing filter has also been rotated by 90 ° with respect to the starting position, the direction of polarization of the light is perpendicular to that of the polarizing filter, so that no light passes through the polarizing filter

Polarization filter can occur.

For blue light, the retardation layer does not change the polarization state at 0 ° orientation of the feature relative to the polarization direction of the incident light so that the polarization filter of the security feature oriented perpendicular to the incident light prevents the blue light component from passing. Since the retardation layer causes a phase shift corresponding to the wavelength, the polarization direction of the light is not changed regardless of the relative orientation of the anisotropy layer to the original polarization direction. However, a change of the blue light component passing through the polarizing filter occurs because the polarizing filter direction changes as the security feature rotates relative to the polarization direction 6 'of the incident light and thus the direction of polarization of the light emerging from the retardation layer. The intensity increases with increasing twist angle from 0 ° to 90 °.

In the last line of the table, the orientation of the security feature relative to the polarization direction of the light emitted by the display surface is indicated by the geometric shape and its orientation. In addition, a color impression is given in words, which is caused by the color addition of the red, the green and the blue light portion of the originally a white impression, from the

Display area emerges light. The orientation 0 ° results in a light green color impression. If the security feature is rotated by 22 °, the color impression changes to a medium to dark green color impression. Below 45 ° results in a violet-colored and below 90 ° a magenta color impression.

In Fig. 12, another possible embodiment is shown schematically. The anisotropic direction is oriented in this case at the orientation 0 ° of the feature parallel to the polarization direction of the incident light. The one with the

Security feature associated polarization filter has a polarization direction, which is oriented perpendicular thereto. Furthermore, the polarizing filter is called dichroic Polarization filter is formed, the only polarized in the illustrated example, light in the red wavelength range or influenced with respect to the polarization state. Green and blue light can, regardless of the state of polarization

Pass polarizing filter. In this embodiment shown schematically, it is assumed that for the different rotations 0 °, 22 °, 45 °, 90 °, the color impression resulting from the color addition is shown in a circle. An intensity of the individual color components is indicated by a hatching of the ellipses assigned to the individual colors, which would be superimposed congruently in a real executed object and here are pulled apart only for the sake of illustration and each indicate the rotation of the feature relative to the original orientation. While a green-blue to turquoise color impression results for the twists at 0 °, 22 °, 45 °, which slowly brightens, results in a white color impression at 90 °.

In Fig. 13, the same situation as shown in Fig. 12, but with a

Polarization filter is used, the light of all wavelengths in terms of

Polarization state influenced. The resulting brightnesses are indicated by the respective hatch density. In the overlay the color impression changes from black to bright expectant grayscale to white with a rotation of the security feature 2 0 ⁰ 22 °, 45 ° ⁰ to 90.

FIG. 14 shows a further embodiment of a security document in which the polarization filter 31 is formed in a middle layer of the security document. Between the polarizing filter 31 and the surface 12 and the rear surface 15 of the security document 1 1 is in each case a structured retardation layer 58, 58 'is arranged, each having different areas 61-64, which vary individually with respect to the anisotropic and / or anisotropy. By way of this it is possible to store an image or an information in the two delay layers 58, 58 '. In verifying, depending on the orientation of the document, the first or second image (the first information or the second information) is perceptible to a viewer 105. If, for example, the security document 1 1 is viewed in transmitted light in front of a display surface 3 emitting poloarised light, in such a way that the rear surface 15 of the display surface and the surface 12 of the security document 1 1 faces the viewer, then the viewer takes in the Delay layer 58 stored Information or the stored first image true. If, however, the security document 11 is viewed in transmitted light in front of the display surface 3 in such a way that the surface 12 faces the display surface and the rear surface 15 faces the viewer, the second image stored in the delay layer 58 'or the image stored therein Information perceivable to the viewer. The rotation dependence for a rotation about an axis 33, which is perpendicular to the surfaces 12, 15, is retained for both images. If the security document 1 1 is viewed in transmitted light unpolarized light, none of the images is perceptible.

It is understood by those skilled in the art that only exemplary embodiments are shown here. The individual features described may be in any

Combinations for the realization of security features, verification systems and verification procedures are used.

LIST OF REFERENCE NUMBERS

1 verification system

2 security feature

3 display device

4 display area

5 lights

5 'transmitted light

5 "reflected light

6, 6 'polarization direction of the light

7 first sense of rotation

8 second direction of rotation

10 area (considered area of the security feature)

1 1 security document

12 Surface of the security document

13 see-through window

14 circumferential edge (area) of the see-through window

15 rear surface

18 personal computers (PC)

20 detection device

21 length

31 polarizing filter

32 pole filter direction (polarizer)

33 axis

51 -55 layers

56 Viewing page

57 Einstrahlseite

58, 58 'retardation layer

d thickness

59 optical axis

60 lateral extent

61, 62 areas

71 elliptical area

72 polarization-dependent hologram

81 anisotropy direction 91 Coordinate system (stationary with regard to the security feature and the associated polarization filter)

92 X-axis

93 Y axis

94 Z axis

101 coordinate system (stationary with display device)

102 X-axis

103 Y axis

104 Z-axis

105 viewer

Claims

claims

1 . Method for verifying a value or security document (1 1)

comprising the steps:

Operating a display device (3) which is formed separately and independently of the value or security document to be verified and from whose display surface (4) emerges polarized light (5) at each exit location,

Arranging the value or security document (1 1), which comprises at least one security feature (2) whose transmission properties are dependent on the polarization of the light (5) to be transmitted, before the

Display area,

Detecting the light emitted by the display device (4) and by the security feature (2) transmitted light (5 ') and

Evaluating the transmitted light (5 ') and deriving a

Verification decision.

2. The method according to claim 1, characterized in that an orientation of the entire value or security document (1 1) relative to the

Display device (3) is varied and the transmitted light (5 ')

Orientation-dependent is evaluated.

3. The method according to claim 2, characterized in that an orientation of the entire value or security document (1 1) is varied by a rotation about a normal of the display surface (4) of the display device (3) is performed.

4. The method according to any one of the preceding claims, characterized in that the transmitted light (5 ') recorded spatially resolved and evaluated.

5. The method according to any one of the preceding claims, characterized in that the transmitted light (5 ') is detected wavelength resolved.

6. The method according to any one of the preceding claims, characterized in that a colored representation on the display surface is changed and the transmitted light is correlated with the color representation is evaluated.

7. The method according to any one of the preceding claims, characterized in that moire effects are evaluated.

8. The method according to any one of the preceding claims, characterized in that the display device (3) is operated so that emerges from the display surface homogeneously and uniformly polarized light.

9. The method according to any one of the preceding claims, characterized in that the value or security document in front of the display surface of the

Display device is arranged, that a side surface of the value or security document, which has a maximum areal extent, is aligned parallel to the display surface.

10. value or security document (1 1) comprising a document body,

which comprises at least one security feature with a see-through region (13) which has a transmission for light (5 '),

characterized in that

the security feature (2) has a transmission for at least one wavelength of light (5), which transmission is dependent on a polarization state of the incident light (5).

1 1. Security or security document according to claim 10, characterized in that the security feature (2) comprises a plurality of transmitting areas (61-64) which are at least partially different

Have anisotropy properties.

12. A security or security document according to claim 1 1, characterized in that the plurality of transmissive regions (61-64) comprises a group of first regions whose anisotropic properties with respect to

Anisotropy strength and / or anisotropy direction of the

Distinguish anisotropy properties of the remaining areas, wherein the one group of areas arranged in a spatial pattern in the document body, which encodes a first information.

13. value or security document according to claim 10 to 12, characterized

characterized in that the security feature (2) comprises at least one polarizing filter (31).

14. value or security document according to claim 10 or 13, characterized

characterized in that the security feature (2) comprises a plurality of

Polar filter elements comprises, which have at least partially different polarization properties.

15. Value or security document according to claim 14, characterized in that the plurality of Polfilterelemente a group of first

Comprises polarizer elements all having a same polarization characteristic different from the polarization characteristics of the remaining ones of the polarizing filters, polarization elements of the one group being arranged in a second spatial pattern in the document body and the second pattern encoding second information.