WO2016079174A1

WO2016079174A1 - Method and device for detecting radiated light and method for producing same

Info

Publication number: WO2016079174A1
Application number: PCT/EP2015/076950
Authority: WO
Inventors: Lazar KULIKOVSKY; Manfred Paeschke; Olga Kulikovska; Markus Tietke
Original assignee: Bundesdruckerei Gmbh
Priority date: 2014-11-20
Filing date: 2015-11-18
Publication date: 2016-05-26
Also published as: DE102014223745A1; EP3221853B1; EP3221853A1

Abstract

The invention relates to a method and to a device for detecting radiated light (3) from a security document (3), wherein the device (1) comprises at least one optical waveguide body (4), the optical waveguide body (4) comprises or forms at least one optical waveguide channel (6), the optical waveguide channel (6) comprises an inlet (7) and at least one first outlet (7), the wall surfaces (9, 9a, 9b) that enclose the optical waveguide channel (6) are completely reflective, and the optical waveguide body (4) is designed without any lenses, and to a method for producing the same.

Description

Method and device for detecting emitted light and method of manufacture

The invention relates to a device and a method for detecting light which is emitted by a security document, and to a method for producing such a device.

It is known to detect light by means of an optical system which is emitted, transmitted, reflected or scattered from a surface of a security document. Depending on the properties of the light detected in this way, in particular an authenticity check can be carried out.

Optical systems which are used for detecting the radiated light regularly consist of a plurality of lenses which image the surface or a subregion of the surface of the security document into a detector plane of an optical sensor.

Since the light intensity, that is the amount of light per detector surface, is squared with the measuring distance, e.g. a distance between an entrance surface of the optical

Systems and surfaces to be imaged decreases, optical systems with a large aperture and a small measuring distance are used for low-luminance surfaces to capture as much light as possible. Here, the aperture designates a diameter of an inlet opening of the optical system, in particular the diameter of an entrance lens. The entrance surface may be equal to the detector surface, in particular when light from the surface directly, so without radiating through further optical element, strikes the detector.

The larger the lens and the smaller the measuring distance, the larger the solid angle from which light can be picked up. However, small measuring distances,

in particular, measuring distances which are smaller than a focal length of an entrance lens of the optical system, due to the beam divergence to light losses in the system, the light being e.g. can be absorbed by the housing.

Also, such systems lead to an increased dependence of the measurement result on both the measuring distance and a position of the security document relative to an optical axis of the optical system. Thus, the use of such an optical system may require a high positioning accuracy.

Furthermore, each lens of the optical system causes low reflections and thus light losses. Another disadvantage is the high construction costs and the high space requirement of these optical systems with lenses.

The technical problem is to provide a device and a method for detecting emitted light of a security document and a method for producing such a device, which allow detection of a desired amount of light, but at the same time a space requirement, weight, construction costs and light losses and positioning sensitivity reduce.

The solution of the technical problem results from the objects with the features of claims 1, 15 and 16. Further advantageous embodiments of the invention will become apparent from the dependent claims.

It is a basic idea of the invention to make a device for detecting light which is emitted by a security document lens-free. Furthermore, a light channel with a free body shape can be provided, wherein the free body shape is selected such that a surface of the security document to be imaged having a predetermined geometry is imaged by the light channel of the device onto an optical sensor, in particular on its active surface, with a predetermined geometry. Thus, the light emitted, reflected or scattered from the surface to be imaged can be directed completely or in large part through the light channel onto the active surface.

Proposed is a device for detecting emitted light of a security document. Here, the light from the security document,

especially from the surface of the security document. The emitted light may denote diffused light, reflected light, transmitted light or emitted light.

A security document can be any document that has a

physical entity that is against unauthorized production and / or falsification protected by security features or elements. 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. A security document may include multiple security features and / or security elements. As defined herein, a security document can always be a security element. Examples of security documents, which also include value documents representing a value, include, for example, passports, identity cards, driving licenses, identity cards, access control cards, health insurance cards, banknotes, postage stamps, bank cards, credit cards,

Smart cards, tickets and labels.

The security document can in this case in particular light-scattering,

contain or have photoluminescent / phosphorescent elements or electroluminescent elements, in particular pigments. These allow a verification of authenticity depending on emitted photo or

Electroluminescent radiation when such luminance-sensitive element, e.g. by light and / or an electric field is excited. In such a case, however, it is not absolutely necessary for the authenticity verification to make an optical image of a subarea of the surface, but only to detect the amount of emitted light.

In this case, the device may in particular be part of a device for checking the authenticity of the security document. Such a device enables a verification of the authenticity of the security document, in particular by an evaluation of

Properties of the radiated light.

The device comprises at least one light guide body. As explained in more detail below, the light-guiding body may be formed as a coated glass body or comprise such. Alternatively, the light guide body can be made as a solid profile with at least one, e.g. be formed with air or another transparent material filled, Lichtleitkanal.

The light guide body has at least one light channel or forms such. The light channel has an inlet opening and at least one first outlet opening. The inlet opening and the first outlet opening are thus connected by the light channel. The inlet opening here denotes an opening through which the light emitted by the security document enters the light channel. The outlet opening accordingly designates an opening through which the light which has entered and is radiated through the light channel can exit or exit the light channel.

Next, the light channel enclosing wall surface or enclosing wall surfaces are formed completely reflective. This means that no light can escape from the light channel through the wall surface (s). For example, the wall surface (s) can be designed to be mirror-like.

According to the light guide body is formed lens-free. This means that the light guide body does not comprise a lens or an optically equivalent element.

In particular, the light guide body does not comprise a lens or optically equivalent element which serves for optical imaging and / or light bundling.

Thus, the feature that the light guide is formed lens-free, mean that the light channel is formed such that a direction of the through

Inlet opening in the light channel entering light is changed exclusively by reflection on the wall surfaces. Alternatively or cumulatively, the feature that the light guide body is formed lens-free, mean that a refraction,

Beam focusing and / or beam scattering of the light entering through the inlet opening in the light channel is carried out exclusively by reflection on the wall surfaces. It can therefore no optical element for changing the beam direction of the light, the

Refraction, be arranged for beam focusing and / or beam scattering in and / or along the light channel.

The property that the light guide body is formed lens-free, but does not necessarily exclude that one or more optical elements, e.g. Mirror or beam splitter to be covered by the light guide body. However, such optical elements do not serve for light bundling and / or optical imaging.

In particular, the inlet opening and / or the first outlet opening can / can be formed lens-free. This means that at the inlet and / or the

Outlet opening no change in the beam direction of the light, no refraction, no beam focusing and / or no beam scattering, in particular by an optical element takes place.

Thus, the light channel can be in direct optical communication with an environment via the inlet opening. This can mean that light is changed without change

Properties of the environment in the light channel can radiate. Furthermore, the light channel via the outlet opening can be in direct optical connection with an environment or with an optical sensor explained in more detail below. This may mean that light can radiate out of the light channel into the environment or onto the optical sensor without changing properties.

In other words, the light guide body can be formed without imaging elements, the light guide body not comprising an element for optical imaging. However, this does not rule out that a beam guide for detecting light is performed by the light guide body.

This results in an advantageous manner that of the surface of the

Security document emitted light and through the light channel, for. can be passed to an optical sensor. Subsequently, properties of the light detected by the optical sensor can be determined and evaluated. In order to determine these properties, no optical imaging of the surface or a subarea thereof is required. In particular, optical imaging is not required if only the amount or intensity of the light emitted from areas of the surface of the security document is to be detected.

The proposed device advantageously enables loss-free detection of the radiated light, wherein construction costs and a space requirement due to the unnecessary lenses are minimized.

In a further embodiment, the light channel is designed as a free-form body. In particular, a design of the free-form body, in particular the formation of the inlet and outlet opening, depending on a geometry and position of a radiating surface (surface to be imaged) and in dependence on a geometry of an active surface of an optical sensor can be selected. In particular, the inlet opening can be at any geometry and / or position of the radiating Surface and the exit opening are adapted to the geometry of the active surface of a sensor. In particular, a shape and / or an area of the

Be inlet opening different from the shape or area of the outlet opening.

For example, an inlet opening may be rectangular and an outlet opening may be circular or vice versa. Thus, e.g. Radiation from a radiating strip of the security document without large light losses, in particular by multiple reflection, be directed to a circular active surface.

The light channel, in particular the geometric shape of the free-form body and the geometry of the inlet and outlet opening, can be chosen such that a surface of the security document to be imaged with a predetermined geometry through the light channel of the device to an optical sensor, in particular on its active surface, is imaged with a predetermined geometry. For example, the area to be imaged can be rectangular, square, circular or oval.

Of course, other geometric shapes are conceivable. The active surface may in particular be rectangular or square. Again, other geometric shapes are conceivable.

If the device is placed on the security document to be detected or arranged at a predetermined distance above the surface thereof, the light channel thus formed can radiate the light emitted from the surface to be imaged, e.g. emitted, reflected or scattered light or a predetermined percentage, e.g. more than 90% or more than 95% of which are directed by the light channel to the active surface.

The shape of the light channel can thus be selected depending on the geometry of the surface to be imaged and the active surface of the desired optical sensor. As a result, a reliable optical detection of a surface to be imaged with a predetermined geometry and with a desired optical sensor can advantageously take place. If an optical sensor with a predetermined geometry is to be used, the shape of the light channel can advantageously provide good optical detection for various surfaces to be imaged. Thus, a flexible adaptation of the optical detection can take place. A freeform body may in particular have an asymmetrical shape or an irregular contour.

In a further embodiment, the device comprises at least one optical sensor, wherein the optical sensor is arranged in or at the first outlet opening. The optical sensor can in this case comprise or have an active surface, wherein the optical sensor can generate an output signal as a function of the light radiating or incident on this active surface.

The arrangement of the optical sensor at or in the first exit opening may mean that the light directed through the light channel towards the first exit opening and / or the exit light from the first exit opening is completely or at least a predetermined proportion, e.g. at least 90%, on the active surface radiates or falls.

The active surface may in this case have a predetermined geometry and / or predetermined dimensions. In this case, a geometry of the outlet opening and / or dimensions of the outlet opening may correspond to the geometry or dimension of the active area.

Thus, the active surface may be arranged at the outlet opening also within the light channel. This can e.g. mean that the light channel encloses the active surface of the optical sensor at its outlet opening. Here can between the

Wall surface of the light channel and the active surface no or a predetermined

(small) distance may be present. If there is no distance, then the wall surface of the light channel can be arranged at the first outlet opening flush with edges of the active surface. Thus, the light channel can be in direct optical communication with the active surface of the optical sensor via the exit opening. In this case, it may be possible that no light exits the first outlet opening into an environment. However, the optical sensor, in particular its active surface, can also be arranged outside the first outlet opening.

Overall, however, results in an advantageous manner that reduce the light losses. In a further embodiment, the light channel has at least one branching into a first sub-channel with the first outlet opening and at least one further sub-channel with a further outlet opening. For example, the light channel may comprise a main channel section between the inlet opening and the branch. Furthermore, the light channel may comprise a first part-channel section between the branch and the first outlet opening. Accordingly, the light channel may comprise a further partial channel section between the branch and the further outlet opening. Of course, the light channel, in particular at least one of the sub-channels or the main channel section, have a further branch.

This results in an advantageous manner that light which is incident on the light channel can be spatially divided, in order, as explained in more detail below, to provide spatially separate detection of the light, e.g. by a plurality of spatially separated optical sensors to allow.

In a further embodiment, the device comprises a beam splitter which splits light, in particular from the main channel section, in a predetermined ratio onto the first sub-channel and the at least one further sub-channel, e.g. redirects or radiates into them. The beam splitter may be located at / in front of the branch. For example, the beam splitter can direct light from a main channel section of the light channel in a predetermined ratio into the first sub-channel and into the at least one further sub-channel.

The predetermined ratio may be a light amount ratio or

Be light intensity ratio. The ratio may vary depending on the light characteristics to be detected and / or the sensitivity of optical sensors to the

Outlet openings of the sub-channels are determined. Preferably, the predetermined ratio may be 1: 1. Of course, however, other conditions are conceivable.

In this case, the beam splitter denotes an optical element, by means of which a beam direction of at least part of the light radiated onto the beam splitter is changed.

In particular, a beam direction of a first portion of this light can not be changed by the beam splitter, wherein a beam direction of the remaining portion is changed by the beam splitter. Of course, however, too

Beam directions of both shares are changed.

This results in an advantageous manner as reliable as possible division of the light for transmission in different sub-channels.

In an alternative embodiment, the branching is designed such that the light at the branch, in particular the light from the main channel section, is split in a predetermined ratio onto the first and the at least one further sub-channel. For example, the branch may be formed such that the light from a main portion of the light channel radiates in a predetermined ratio in the first sub-channel and in the at least one further sub-channel. This results in an advantageous manner a beam splitter-free distribution of light. The predetermined ratio may in turn denote a light quantity or light intensity ratio. Preferably, the ratio is 1: 1. Of course, however, other conditions are conceivable. For example, the branching can be achieved by a suitable design and / or a suitable geometric course of the

Wall surface / s be provided.

This results in an advantageous manner, a simple provision of

Light branching.

In a further embodiment, the device comprises at least one further optical sensor, wherein the at least one further optical sensor is arranged in or at the first outlet opening or in or at the at least one further outlet opening.

Thus, in a first alternative, the first and the further optical sensor can be arranged in or at the first outlet opening. In this case, the two optical sensors can be used to detect and optionally determine mutually different properties of the light.

For example, the first and the further optical sensor may be arranged spatially adjacent to one another in or at the first outlet opening. The arrangement of the optical sensors on or in the first outlet opening may mean that the light conducted through the light channel towards the first outlet opening and / or the light emerging from the first outlet opening is completely or at least at a predetermined proportion, eg at least 90% the entirety of the active surfaces radiates or falls.

The active surfaces can be arranged inside or outside the light channel. Preferably, no or only a predetermined (small) distance between edges of the active surfaces of the two sensors may be present. The active surfaces may be arranged such that the light directed towards the first outlet opening radiates in a predetermined ratio, in particular in equal or unequal parts, to the active surfaces.

As already explained above, in this case, a geometry of the outlet opening and / or dimensions of the outlet opening of the geometry or

Dimension of the active areas, for example an envelope of the active areas. This can mean that the light channel encloses the active surfaces of the optical sensors at its first outlet opening. In this case, no or a predetermined (small) distance may be present between the wall surface of the light channel and the active surfaces. If there is no distance, then the wall surface of the light channel can be arranged flush with the active surfaces at the first outlet opening. Thus, the light channel may be in direct optical communication with the active surfaces of the optical sensors via the exit aperture.

In the second alternative, the further optical sensor is arranged spatially separated from the first optical sensor. This advantageously reduces mutual interference of the optical sensors by the disadvantageous

Output signal of the sensors can be falsified.

In accordance with the statements regarding the arrangement of the first optical sensor at or in the first outlet opening, the further optical sensor can be arranged on or in the further outlet opening such that the light guided through the light channel to the further outlet opening and / or that from the further outlet opening

Exiting light completely or at least to a predetermined proportion, for example at least 90%, radiates or falls on the active surface of the other optical sensor. The further optical sensor can in this case within or au ßerhalb the other

Subchannel be arranged. Furthermore, a geometry and / or dimension of the further outlet opening can be adapted to the geometry and / or dimension of the active surface of the further optical sensor. Reference is made to the corresponding previous statements.

In a further embodiment, the first optical sensor is a spectral sensor and the at least one further sensor is a light quantity sensor. This results in an advantageous manner that mutually different properties of the light are detected by mutually different sensors. This results in an advantageous way a more accurate detection and determination of these properties.

In a further embodiment, a cross section of the light channel decreases from the inlet opening towards the at least one outlet opening. The cross section may in this case designate a cross-sectional area or a, in particular maximum, diameter of the light channel. Alternatively, the cross section of the light channel increases from the inlet opening towards the at least one outlet opening. However, it is not excluded that the light channel has sections with a constant cross section. A size of the cross section may, for example, be detected along a central axis of the light channel. Along the light channel, the cross-section may be e.g. non-permanent, especially sudden, continuous or differentiable change. In particular, a cross section of the inlet opening may be larger or smaller than a cross section of the at least one outlet opening. This advantageously results in a desired concentration or a desired distribution of the light irradiated into the light channel.

In a preferred embodiment, at least a portion of the light channel, in particular the entire light channel, frusto-conical or truncated pyramid shaped. Alternatively or cumulatively, at least one subsection of the at least one subchannel, in particular the entire subchannel, may be frusto-conical or truncated pyramidal. This does not exclude that at least one further subsection of the light channel and / or the at least one subchannel is cylindrical or cuboidal. This results in an advantageous manner as simple as possible mechanical production of the light guide body. In a further preferred embodiment, the light channel is designed such that a back reflection-free propagation of the light from the inlet opening to the at least one outlet opening takes place.

This may mean that a direction of the light introduced through the inlet opening in the light channel is only changed in such a way that the beam direction in each section of the light channel comprises a portion which is oriented parallel to a center line or central axis of the light channel and in the direction of the outlet opening, is oriented in particular from the inlet opening to the outlet opening. This is not

excluded that the beam direction has a further portion transverse to this center line or central axis. However, it is essential that the beam direction has no or an only negligible proportion in a direction which is oriented parallel to the center line or central axis and in the direction of the inlet opening.

Alternatively, the light channel is formed such that an intensity of the in the

Propagation of the light from the inlet to the at least one outlet opening back-reflected radiation is less than a predetermined threshold. In particular, the intensity of the back-reflected radiation may be less than or equal to 10% of the intensity of the light irradiated through the inlet opening.

This results in an advantageous manner a reliable detection.

In a further embodiment, a wall surface inclination and / or a length of the light channel and / or at least one subchannel is / are selected such that the back reflection-free propagation is ensured as a function of a dimension of the inlet opening and a dimension of the outlet opening. The inlet and

In this case, the outlet opening designates the inlet opening of the respective channel section, that is to say, for example, of the previously explained main channel section or

Subchannel section.

Here, the dimension of the inlet opening in dependence on a dimension of the surface to be detected of the security document and / or a desired or necessary distance of the inlet opening of this surface and a desired angle of incidence of the radiated from the surface to be detected light on the Entry opening to be determined. The angle of incidence may in this case be an angle relative to a line which is oriented perpendicular to the inlet opening, in particular an angle relative to an optical axis of the inlet opening.

The dimension of the outlet opening may be dependent on the dimension of the active surface of the optical sensor. In particular, the dimension of the

Outlet opening correspond to the dimension of the active area or to a

predetermined (small) dimension greater than the dimension of the active surface.

The wall surface slope may be given relative to a central axis or centerline of the light channel. If the (sub) channel has a curvature or a kink, the wall surface inclination can be given relative to a tangent to the central axis or center line. However, it is also possible that in this case the

Wall surface inclination is given relative to the optical axis of the inlet opening of the light channel or an inlet opening of a sub-channel. The center line of the inlet opening in this case denotes a perpendicular to an inlet surface oriented line, which

Inlet surface intersects in the geometric center.

The wall surface slope may vary along the light channel, especially within a predetermined pitch interval. This may mean that the

Wall surface inclination along the light channel and / or the at least one sub-channel is greater than or equal to a predetermined minimum inclination and / or less than or equal to a maximum inclination. In this case, the wall surface inclination may change non-steadily along the light channel, in particular in a sudden, continuous or preferably differentiable manner. In particular, the inclination may be given by an angle between the central axis and a line of intersection through the wall surface, the section line lying in a sectional plane spanned from the central axis and a vector perpendicular to the central axis or center line with the vector oriented from the central axis or midline towards the wall surface. In particular, in this case the angle may be defined by the angle between the central axis and a tangent to the cutting line in the

Intersection of the section line to be given to the vector.

Depending on the geometric design of the light channel, the beam direction of the light irradiated into the light channel, in particular in a multiple reflection, so change that along the light channel of the oriented parallel to the center line or central axis of the light channel and in the direction of the outlet opening portion decreases. Thus, the wall surface inclination and the length of the light channel can in particular be selected such that this proportion is greater than zero along the light channel in each section.

In a further embodiment, the wall surface inclination changes along the light channel and / or along at least one subchannel. This advantageously results in a further minimization of light losses.

In a further embodiment, the light channel is formed by a translucent material. The propagation of the light in the light channel takes place here within the body. In particular, the light channel can be formed by a glass or plastic body. In this case, the glass or plastic body may be coated, wherein by the coating completely reflecting wall surfaces of the glass or

Plastic body are provided. Alternatively, there is air in the light channel.

This advantageously allows a simple production of the light channel with the desired properties.

Further proposed is a method for producing a device for detecting emitted light of a security document. In this case, at least one light guide body is provided, wherein at least one light channel is provided in the light guide body. The light channel has an inlet opening and at least one

Outlet opening, wherein the light channel encompassing / n wall surface / n is formed completely reflecting / are.

According to the light guide body is formed lens-free.

The method advantageously makes it possible to produce a device for detecting emitted light according to one of the previously explained

Embodiments. In particular, the method can thus comprise all the method steps which are necessary for producing a device according to one of the previously explained embodiments. Further proposed is a method for detecting emitted light, in particular an amount of intensity, of a security document, wherein a device according to one of the above-explained embodiments is arranged relative to a surface of the security document such that light emitted from at least a portion of the surface passes through the Inlet opening enters the light channel.

This results in an advantageous manner detection of emitted light, which does not require a cost-intensive and space-consuming device.

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

1 shows a schematic cross section through a device according to the invention,

2 shows a schematic longitudinal section through a light channel,

Fig. 3 is a schematic longitudinal section through a light channel in another

embodiment,

4 shows a schematic cross section through a device according to the invention in a further embodiment,

Fig. 5 is a perspective view of a device according to the invention in a further embodiment and

6 shows a schematic cross section through a device according to the invention in a further embodiment.

In Fig. 1 is a schematic cross section through a device 1 for detecting radiated light 2, which is exemplified by arrows, one

Security document 3 shown. The device 1 comprises a light guide 4 and an optical sensor 5, which may be formed, for example, as a photodetector, in particular as a CCD sensor or CMOS sensor. The light guide 4 has a light channel 6. The light channel 6 has an inlet opening 7 and an outlet opening 8 on. Here, it is shown that the radiated light 2 enters through the inlet opening 7 into the light channel 6 and is reflected along the light channel 6 by wall surfaces 9 of the light channel 6 and is therefore blasted to the outlet opening 8. That by the

Outlet opening 8 emerging light 2 radiates on an active surface 10 of the optical sensor 5. The optical sensor 5 is in this case arranged at the outlet opening 8.

The wall surfaces 9 of the light channel 6 are formed completely reflecting. Thus, light 2 emerges from the light channel 6 exclusively via the outlet opening 8 from the

Light channel 6 off.

It is further shown that the light guide 4, in particular the light channel 6, is formed lens-free. In particular, no lens is provided for beam focusing, refraction or beam steering in or at the inlet opening 7, in or on the light channel 6 or in or at the outlet opening 8.

In Fig. 1 it is shown that the light channel 6 is frusto-conical. In this case, a diameter of the light channel 6 decreases from the inlet opening 7 towards the outlet opening 8.

Furthermore, it is shown by way of example that a back reflection-free propagation of the light 2 from the inlet opening 7 to the outlet opening 8 takes place. By a dashed line, a central axis z of the light channel 6 is shown, which is oriented orthogonal to a surface of the inlet opening 7 and is oriented from the inlet opening 7 to the outlet opening 8. In Fig. 1 it is shown that light beams 2 before and after reflection on the wall surface 10 of the light channel 6 in each section of the light channel 6 have a proportion which is oriented parallel to the central axis z and towards the outlet opening 8. In particular, the direction before or after a reflection of the light rays 2 contains no portion which is oriented parallel to the optical axis z towards the inlet opening 7.

In Fig. 2, a light channel 6 is shown in a first embodiment in a longitudinal section. In the embodiment shown in Fig. 2, the light channel 6 may be formed, for example, a truncated pyramid. It is shown that a first wall surface 9a or a first wall surface section is oriented parallel to the central axis z of the light channel 6. In the exemplary embodiment illustrated in FIG. 2, the central axis z of the light channel 6 again corresponds to a center line of the inlet opening 7, which is oriented perpendicular to the surface of the inlet opening 7 and cuts it in a geometric center. The central axis z does not run along the light channel 6 in the middle in the light channel 6.

The first wall surface 9a is thus not inclined. Further illustrated is a second

Wall surface 9b and a second wall surface portion which is inclined relative to the central axis z, in particular with a tilt angle ß.

In FIG. 2, E denotes a diameter or a width of the inlet opening 7. D also denotes a diameter or a width of the outlet opening 8. LOB designates a desired or necessary distance of the inlet opening 7 from the surface of the security document 3 to be detected along the central one Axis z. Further illustrated is a length L _{M of} the light channel 6 along the central axis z.

The reference character α denotes by way of example a minimum angle of incidence of the light 2 on the first wall surface 9a. The angle γ denotes a detection angle.

Also shown is an exemplary course of a light beam 2, which impinges on the first wall surface 9a at the inlet opening 7 with the minimum angle of incidence α. This light beam 2 is reflected at the first wall surface 9a with the angle of incidence, that is, the angle a, and radiated toward the second wall surface 9b. The beam path of the light beam 2 is shown here for several reflections, wherein it is apparent that the angle of incidence and reflection decreases in a reflection on the wall surfaces 9a, 9b along the light channel 6.

For the embodiment illustrated in FIG. 2, the following relationships apply: tan β = (E - D) / L _M formula 1 and tan a = (2 × LQB) / E formula 2 and α> (Ν + 1) χ? Formula 3.

Where N is the number of reflections.

The length L _M and / or the size of the inlet opening E and / or the inclination angle β can be adjustable parameters during the production of the light guide body 4. By formula 1, the relationship between inclination angle ß, the length of the light channel L _M and the size of the inlet and outlet openings E, D is given. These parameters can, for example, be determined in such a way that the light rays entering through the inlet opening 7 are radiated through the light channel 6 without back reflection in the direction of the inlet opening 7. For example, depending on this relationship, a maximum number of reflections can be determined, which can pass through the light rays entering through inlet opening 7 without being returned in the direction of

Inlet opening 7 to be reflected. Thus, they determine the minimum angle of incidence for a beam that can reach the outlet opening 8 after multiple reflection. In Fig. 2 it is shown that for a beam with angle of incidence a after a third reflection from the second wall surface 9b, a back reflection in the direction of

Entry opening 7 takes place.

FIG. 3 shows an exemplary longitudinal section through a light channel 6 in a further embodiment. In contrast to that shown in Fig. 2

Embodiment is in this case, the first wall surface 9a and the first

Wall surface portion with respect to the central axis z inclined with the inclination angle ß. In this embodiment, the following relationships apply: tan β = (E - D) / 2 × L _M formula 4 and tan γ = (E - D) / (2 × L _OB ) formula 5 and α = 90 - γ - β Formula 6.

FIG. 4 shows a schematic cross section through a device 1 according to the invention in a further embodiment. In contrast to the embodiment illustrated in FIG. 1, the light channel 6 has a branching of the light channel 6 into a first sub-channel 11a and into a second sub-channel 11b. The first sub-channel 1 1 a here has the first outlet opening 8, wherein the second sub-channel 1 1 b has a further outlet opening 12. The device 1 further comprises a further optical sensor 13 with an active surface 14 of the further optical sensor 13. Also shown is a beam splitter 15, the light from a main channel section 16 of the

Light channel 6 in a predetermined ratio in the first sub-channel 1 1 a (first sub-channel section) and in the second sub-channel 1 1 b (second sub-channel section) irradiates.

The further optical sensor 13 is arranged at the further outlet opening 12, wherein light emerging from the further outlet opening 12 2 falls on the active surface 14 of the further optical sensor 13.

The optical sensors 5, 13 can serve to detect various properties of the light 2. Also, the optical sensors 5, 13 with each other

different optical elements, for example different optical filters, e.g. with different color filters. In particular, in this case, the optical sensors 5, 13 serve to detect different properties of the light 2.

For example, For example, the optical sensor 5 can be designed as a photodetector or as a photodetector combined with a spectral filter. The further optical sensor 13 may be formed, for example, as a color sensor or spectral sensor. Also, the further optical sensor 13 may be formed as a CCD sensor.

Thus, e.g. a temporal course of the light intensity is detected by the first optical sensor 5, wherein a spectral. By the further optical sensor 13

Composition, for example, a color of the light 2 is determined. Further, a central axis ζ of the first sub-channel 1 1 a is shown in Fig. 4, which corresponds to the central axis z of the main channel portion 16 of the light channel 6, wherein the central axis of the main channel portion 1 6 corresponds to a center line of the inlet opening 7. Also shown is an inlet opening 18 of the first sub-channel 1 1 a, wherein the central axis ζ corresponds to a center line of the inlet opening 18 of the first sub-channel 1 1 a. Wall surfaces of the first sub-channel 1 1 a are in this case inclined relative to the central axis ζ of the first sub-channel 1 1 a.

Next, a central axis z _{2 of} the second sub-channel 1 1 b is shown. The further central axis z ₂ is in this case orthogonal to an inlet opening 1 7 of the second sub-channel 1 1 b oriented and intersects the surface of the further inlet opening 17 in her

geometric center. Wall surfaces of the second sub-channel 1 1 b are in this case inclined relative to the central axis z _{2 of} the further sub-channel 1 1 b. Here, the central axis z _{2 of} the second sub-channel 1 1 b is inclined relative to the central axis Zi of the first sub-channel section 1 1 a.

In Fig. 5 is a perspective view of a device 1 in another

Embodiment shown. Here it is shown that the light channel 6

is formed truncated pyramid. It is further shown that in the outlet opening 8 of the light channel 6, both the first optical sensor 5 and the further optical sensor 13 are arranged side by side. One dimension of the outlet opening 8 is in this case adapted to a dimension and geometry of the overall arrangement of the first optical sensor 5 and the further optical sensor 1 3. In particular, the outlet opening 8 surrounds the rectangular envelope of the active surfaces 10, 14 (see FIG. 4) of the two sensors 5, 13.

As already explained above with reference to FIG. 4, the optical sensors 5, 13 can be designed to detect mutually different properties of the light 2 or to be combined with different optical elements, in particular filter elements.

In the arrangement of the first and the further optical sensor 5, 13 shown in FIG. 5, active surfaces 10, 14 (see FIG. 4) of the optical sensors 5, 13 are arranged in a plane next to one another. As a result, the light front of the incident on the active surfaces of the light 2 can be divided into channels. However, there is no division here the light amplitude. Upon detection, determination and evaluation of properties of the light detected in this way, however, homogeneity of the light distribution in the plane of the active surfaces can be taken into account.

In general, a geometry of the light channel 6 and thus a design and / or arrangement of the wall surface (s) 9, 9a, 9b can be chosen freely. Ideally, however, the shape and arrangement is adapted to a geometry and / or dimension of the active surface 10, 14 of an optical sensor 5, 13. Also, the training and / or arrangement can be chosen such that no back reflection takes place in the light channel 6.

FIG. 6 shows a schematic cross section through a device 1 in a further embodiment. Here it is shown that the light channel 6 branches at a branch into a first sub-channel 1 1 a and a second sub-channel 1 1 b. The branching is achieved here by the formation of the light channel 6, in particular by a corresponding wall surface course. The branching is in this case designed such that light 2 from a main channel section 16 of the light channel 6 in a predetermined ratio in the first sub-channel 1 1 a and the second sub-channel 1 1 b irradiates. Shown is an inlet opening 17 of the second sub-channel 1 1 b and an inlet opening 18 of the first sub-channel 1 1 a. Also shown are central axes z _1; z _{2 of} the first sub-channel 1 1 a and the second sub-channel 1 1 b. Here it is shown that the central axes z _1; z _{2 of} the sub-channels 1 1 a, 1 1 b relative to the central axis z of the main portion 16 are each inclined.

It is further shown that a wall surface inclination of a wall surface of the first sub-channel 1 1 a and a wall surface of the second sub-channel 1 1 b along the first and second sub-channel 1 1 a, 1 1 b changes. The wall surfaces of the first and the second sub-channel 1 1 a, 1 1 b are each formed curved. As already explained with reference to FIG. 4, the first optical sensor 5 is arranged at the first outlet opening 8, wherein the second optical sensor 13 is arranged at the further outlet opening 12.

The proposed device 1 offers several advantages. On the one hand, light losses are reduced since no lenses are used in the device 1. Is the

Outlet opening 8, 12 adapted to the respective optical sensor 5, 13, so also light losses can be minimized thereby, in particular if the active surface 10, 14 of the respective sensor 5, 13, the corresponding outlet opening 8, 12 completely fills or covers.

Furthermore, the proposed device 1 is less sensitive to a lateral positional deviation compared to the lens-based embodiment

measuring radiation source (e.g., the emitting, reflecting, and / or scattering surface of the security document 3), the lateral

Position deviation denotes a deviation perpendicular to the center line of the inlet opening 7. Also, the proposed device 1 is less sensitive to inclination of the surface of the security document 3 relative to this center line. This means that the amount of light directed towards the at least one outlet opening 8, 12 is not or only to a small extent dependent on the lateral positional deviation and / or inclination. Furthermore, the inlet opening 7, in particular its geometry and / or dimension, can be adapted to a geometry and / or dimension of a security feature of the security document 3. Furthermore, the cost and weight of the device 1 can be reduced. Due to the high light efficiency can continue to use cheaper optical sensors 5, 13, which are also flexible in their shape selectable. Also results in a simple adjustment and maintenance.

LIST OF REFERENCE NUMBERS

contraption

2 light beam

3 security document

4 light guide

5 first optical sensor

6 light channel

7 entrance opening

8 outlet opening

9 wall surface

9a first wall surface

9b further wall surface

10 active area

1 1 a first subchannel

1 1 b second subchannel

12 more outlet

13 additional optical sensor

14 active area

15 beam splitter

16 main channel section

17 inlet opening of the second sub-channel

18 inlet opening of the first sub-channel

z central axis of the light channel / main section

Zi central axis of the first subchannel

z ₂ central axis of the further subchannel

E diameter / width of the inlet opening

D diameter / width of the outlet opening

ß inclination angle

α minimum angle of incidence

Y detection angle

LOB distance between the inlet opening and the surface to be measured

LM length of the light channel

Claims

claims

1 . Device for detecting emitted light (3) of a security document (3), wherein the device (1) comprises at least one light guide body (4), wherein the light guide body (4) has or forms at least one light channel (6), wherein the light channel (6 ) an inlet opening (7) and at least one first

Having outlet opening (8), wherein the light channel (6) enclosing

Wall surface / s (9, 9a, 9b) is / are completely reflective,

characterized in that

the light guide (4) is formed lens-free.

2. Apparatus according to claim 1, characterized in that the light channel (6) is designed as a free-form body.

3. Apparatus according to claim 1 or 2, characterized in that the device (1) comprises at least one optical sensor (5), wherein the optical sensor (5) is arranged in or at the first outlet opening (8).

4. Device according to one of claims 1 to 3, characterized in that the light channel (6) at least one branch into a first sub-channel (1 1 a) with the first outlet opening (8) and in at least one further sub-channel (1 1 b) having a further outlet opening (12).

5. The device according to claim 4, characterized in that the device (1) comprises a beam splitter (15), the light (2) in a predetermined ratio to the first sub-channel (1 1 a) and the at least one further sub-channel (1 1 b) divides.

6. The device according to claim 4, characterized in that the branching is formed such that the light (2) in a predetermined ratio to the first sub-channel (1 1 a) and the at least one further sub-channel (1 1 b) is divided.

7. Device according to one of claims 3 to 6, characterized in that the device comprises at least one further optical sensor (13), wherein the at least one further optical sensor (13) is arranged in or on the first outlet opening (8) or in or on the at least one further outlet opening (12).

8. The device according to claim 7, characterized in that the first optical sensor (5) is a spectral sensor and the at least one further sensor (13) is a light quantity sensor.

9. Device according to one of claims 1 to 8, characterized in that a cross section of the light channel (6) from the inlet opening (7) towards the at least one outlet opening (8) is reduced or the cross section of the light channel (6) of the Inlet opening (7) towards the at least one

Increased outlet opening (8).

10. Device according to one of claims 1 to 9, characterized in that

at least one subsection of the light channel (6) and / or at least one subsection of the at least one subchannel (11a, 11b) is frusto-conical or

is formed truncated pyramid.

1 1. Device according to one of claims 1 to 10, characterized in that the light channel (6) is formed such that a non-return propagation of the light (2) from the inlet opening (7) to the at least one outlet opening (8) or that the light channel (6) is designed such that an intensity of the radiation reflected back during the propagation of the light (2) from the inlet opening (7) to the at least one outlet opening (8) is smaller than a predetermined threshold value.

12. The device according to claim 1 1, characterized in that a

Wall surface inclination and / or a length (L _M ) of the light channel (6) and / or at least one sub-channel (1 1 a, 1 1 b) depending on a dimension of the inlet opening (7, 17, 18) and a dimension of the outlet opening (8 , 12) is / are selected such that the return-reflection-free propagation is ensured.

13. The apparatus according to claim 12, characterized in that a

Wall surface inclination along the light channel (6) and / or at least one Subchannel (1 1 a, 1 1 b) changes.

14. Device according to one of claims 1 to 13, characterized in that the light channel (6) is formed by a translucent material or in the light channel (6) is air.

15. A method for producing a device (1) for detecting emitted light (2) of a security document (3), wherein at least one light guide body (4) is provided, wherein at least one light channel (6) is provided in the light guide body (4), wherein the light channel (6) has an inlet opening (7) and at least one first outlet opening (8), wherein the wall (s) (9, 9a, 9b) enclosing the light channel (6) is / are formed to be completely reflecting, characterized that

the light guide (4) is formed lens-free.

16. A method for detecting emitted light (2) of a security document (3), wherein a device (1) according to one of claims 1 to 14 is arranged relative to a surface of the security document (3) such that at least a portion of the surface radiated light (2) through the inlet opening (7) enters the light channel (6).