WO2011104331A1

WO2011104331A1 - Marking device and method for the colored marking of value or security documents

Info

Publication number: WO2011104331A1
Application number: PCT/EP2011/052802
Authority: WO
Inventors: Helmut Wurm; Steffen Baudach
Original assignee: Bundesdruckerei Gmbh
Priority date: 2010-02-26
Filing date: 2011-02-25
Publication date: 2011-09-01
Also published as: PL2539154T3; DE102010010072A1; EP2539154A1; EP2539154B1; EP2539154B9

Abstract

The invention relates to a marking device (1) for a value or security document (2) and to a method for the permanent, in particular distinct, multicolored marking of value and/or security documents (2). The method for the permanent colored marking of a value or security document (2) comprises the following steps: providing a document body (40) which comprises regions having different colors, wherein each of the individual regions is single-colored; providing a marking device which comprises at least one laser light source (5) for generating laser light (6) and a light guide device (8, 8') which is coupled to the at least one laser light source (5) such that a focus (19) of the laser light (6) of the laser light source (5) can be positioned in a controlled manner on or in the document body (40) of the value or security document (2); iteratively deliberately positioning the focus (19) on or in the document body (40) and irradiating the laser light (6') in order to deliberately change the color of one or more regions locally so that subsequently the document body (40) conveys a multicolored color effect to a human observer when irradiated with white light, wherein the laser light (6) is irradiated by means of short or ultrashort laser pulses which have a pulse duration of less than 100 ps or less than 10 ps. As a result, non-linear interactions between the material of the value or security document (2) and the laser light (6') can be utilized for marking. In this way, improved focusing of the laser light (6'), and consequently a higher density of the colored markings establishing the color, can be utilized or produced, so that higher color intensity can be implemented.

Description

Marking device and method for color marking value or

security documents

The invention relates to a method for multicolor marking value or security documents and a marking device, which are designed for a permanent colored marking a value or security document by means of laser light.

Security documents are those documents and objects that are protected by at least one security feature or security element against a

Corruption and / or unauthorized copying are protected.

Security documents that embody a value are also referred to as value documents. Security documents include, for example, identity documents, driver's licenses or motor vehicle papers and documents of value, with value documents, for example banknotes, postage stamps or checks.

At least in some of the security documents or value documents, it is advantageous to be able to mark these permanently, preferably individually. Different methods are known from the prior art, with which value and / or security documents can be marked individually. Historically, most value and security documents have been paper-based and, in particular, have been customized by means of printing techniques, modern security documents and value documents are often at least partially made from plastic materials. Modern identity cards and driving licenses are used, for example, as lamination bodies made of several layers of plastic and

optionally combined one or more layers of paper.

For the permanent individual marking of plastics so-called laser marking methods have been developed in the prior art. For this are individual

Plastic layers to be later marked with a laser, added special pigments. These do not affect transparency in the visible optical range or are not or barely perceptible to a user. If such a layer is irradiated with laser light of sufficient intensity, an increased absorption of the laser light occurs at the pigments. This makes it possible to use energy in the otherwise couple transparent plastic, which then on the amount of energy deposited here to a local coloring, for example via a

Heating and a partial carbonization of the plastic material leads. Depending on the amount of energy applied, a degree of blackening of the plastic can be set in a targeted manner. From individual local pixels, patterns, in particular

Grayscale images, logos and other characters, permanently in the value or

Mark security document.

For a long time, however, the goal has been pursued to highlight the value or security document in color, preferably multi-colored. Ideally, a full-color marking should be possible, which can represent colors from a gamut, which is spanned by preferably three primary colors, such as red, blue and green.

From DE 100 1 1 486 A1 discloses a card-shaped data carrier is known, consisting of at least one layer in which visually readable information in the form of a change in the optical properties due to an irreversibly caused by a laser beam material change are introduced, the absorption capacity of this layer for at least a wavelength due to the laser radiation is at least partially reduced. In this process, original colored or opaque layers are "bleached" in terms of absorption.

DE 30 48 733 A1 discloses an identification card and a method for producing such an identification card with information applied in the form of patterns,

For example, letters, numbers and / or pictures known. The ID card has differently colored, stacked on at least one surface

Layers areas that are at least partially visible through visually recognizable

Personalization data is interrupted. It is envisaged that the information by the action of a controlled laser beam on one or more on a

Plastic carrier one above the other applied color layers are displayed. As a result of the laser irradiation, the color can be changed locally.

From DE 696 05 788 T2 a method is known for producing an object with a colored mark by irradiating the surface of the object with laser light in the form of the mark, wherein the object consists of a plastic composition in at least the area where the mark is applied that at least contains three color-forming components that lose their color-forming ability under the influence of laser light selected and present in a concentration such that at each wavelength between 400 and 700 nm at least a portion of the amount of incident light is absorbed for the character one or more colors are selected, the wavelength of the laser light in the sequence is set to a value depending on the selected color, and then the surface of the object is irradiated with the laser light.

From WO 01/28778 A2 discloses a method for applying colored characters on a data carrier, preferably made of plastic, known by means of a laser system, wherein in at least one surface layer and / or near-surface layer of the data carrier introduced latent pigments in which by energetic excitation a Changing the absorption behavior is carried out at the designated areas of the data carrier by laser irradiation, which is in the IR and / or visible range, energetically excited in such a way that the same pigments

Color change takes place and that after the color change of the laser-irradiated latent pigments, which are not excited by laser irradiation latent pigments excited by irradiation with light waves in the UV wavelength range energetically such that in the thus irradiated pigments colorlessness is brought about.

From DE 100 53 264 A1 a method for writing data, in particular personalization data, on and / or in a data carrier by means of electromagnetic radiation is known, wherein the method any data carrier is provided on and / or in which at least one colorant at least is provided locally, and this colorant is irradiated by means of the electromagnetic radiation of at least one wavelength range, so that there is a change in color of the colorant by bleaching in the region of the irradiation, wherein the color change can be determined by machine and / or by a human eye. This results in an increased security against counterfeiting and manipulation for the data carrier.

From DE 199 55 383 A1 a method for applying colored information to an object is known, wherein the object at least in one

near-surface layer has at least two different coloring particles that change the color of this layer under the influence of laser radiation, the laser radiation is used with at least two different wavelengths to to change the color of this layer, the exposure of the object with

Laser radiation in the vector and / or raster method over a

Zweikoordinatenstrahlablenkeinrichtung and a focusing device for focusing the laser radiation on the layer of the object takes place. At least one beam guiding means is provided for guiding a first laser beam having the wavelength λι and at least one further laser beam having a wavelength λ ₂ , which is different from the wavelength of the first laser beam, via the two-coordinate beam deflecting means and the focusing means to the layer of the object. For the

Zweikoordinatenstrahlablenkeinrichtung is proposed an arrangement of two mutually perpendicular axes rotatably mounted deflecting mirror. A focusing is done by a fixed plan field optics. Since the light does not pass through the planar field optics on the optical axis, chromatic aberration effects occur in the focusing device. In particular, if differently colored laser light is used for marking, this requires a complex compensation.

From DE 10 2006 014 367 A1 a data carrier and a method for its production are known. The data carrier comprises a visually or machine recognizable marking in the form of a pattern of letters, numbers or pictures. In the method of manufacture, a data carrier with a data carrier substrate is provided and a marking layer is applied to the data carrier substrate. The marking is introduced into the marking layer by means of short laser pulses.

In a group of the prior art methods which allow a colored marking, different colorants are incorporated in the value or security document, which conjointly cause a color impression in a human observer via an additive or subtractive color mixture. In the unmarked state, a uniform color impression is produced over the entire surface. Through a local targeted

Altering individual colorants, the color mixture changes, so that locally creates a desired color impression. The practical problem of the prior art methods is to achieve high-contrast intense hues.

The invention is based on the object, an improved method and an improved device for permanent color marking of value or

To provide security documents that eliminate or reduce the disadvantages of the prior art. The object is achieved by a device with the features of claim 1 and a method with the features of claim 9. Advantageous embodiments of the invention will become apparent from the

Dependent claims.

Basic idea of the invention

The basic idea of the invention is the marking of the value and / or

Perform security document with laser light, which is generated with a short pulse laser source. This means that the individual used for marking

Laser light pulses have a pulse duration of less than 100 picoseconds, preferably less than 10 picoseconds. This makes it possible to make the interaction with the material of the document body or the colorants contained therein so that a change of the material and / or the colorant wholly or largely takes place without a thermal interaction. Since the coupling of the energy occurs in a short time window and the process caused by the interaction proceeds so quickly that no or only a very small dissipation of the energy takes place in the form of heat away from the interaction site, the change is well localized. Adjacent to the interaction site, there is no change in the material of the security or security document or the colorants contained therein. This possibility of targeted local marking for the purpose of local

Color change at closely spaced locations, i. with high area

Resolution, without affecting the colourfulness of neighboring locations, allows high contrast and / or intense color impressions to be created for a pattern marked in a document body.

definitions

A security element is a structural unit comprising at least one security feature. A security element can be an independent structural unit which can be connected, for example glued, to a security document, which can also be a value document. It can also be an integral part of a security document. An example of the former is a so-called holopatch (a hologram-containing patch for example, a hologram film section) or a visa stickable to a security document. An example of the latter is an identification document

embossed diffractive surface relief.

A security feature is a structure that is only producible or reproducible with (compared to simple copying) increased effort or not at all unauthorized, or makes forgery and / or falsification visually and / or mechanically recognizable.

As security documents are merely exemplified identity cards, passports, ID cards, access control cards, visa, control characters, tickets,

Driving licenses, motor vehicle papers and documents of value, which in particular include banknotes, checks, postage stamps and credit cards, and any

Smart cards and adhesive labels (for example for product protection). Security documents, which also embody a value, are also referred to as value documents. A sharp distinction between these two terms is often not possible. A

A credit card, for example, represents a security document protected by security features and security elements against counterfeiting and adulteration, which does not directly represent a value beyond the pure material value of the card, but makes it possible to dispose of large assets.

A pulsed laser is a laser that, in contrast to a continuous wave or CW laser that continuously emits laser light, emits laser light in temporally limited portions called pulses. As a short pulse laser is understood here a laser that generates light pulses whose pulse duration is less than 100 picoseconds. The literature also speaks in part of ultrashort laser pulses, with no uniform definition for this. Ultrashort pulses are pulses whose pulse duration is less than 10 picoseconds.

An optical fiber is a fiber of a transparent material to whose

Total internal reflection can be a conduit of light inside the fiber.

A fiber laser is a laser whose active medium in which light-induced emission of electromagnetic radiation occurs is an optical fiber. A pattern typically consists of a multiplicity of juxtaposed pattern units or pixel dots. The pattern units or pixels of a pattern are assigned to each other and arranged laterally in a defined manner,

typically in one or two dimensions of space, and result in the

Overall, a representation, such as an image, a symbol, a logo, a lettering (letters, numbers, alphanumeric characters) or a code (e.g., a bar code). An individualization pattern is a pattern that is used for individualization. In a colored pattern, a pixel may include a plurality of sub-pixels, each of which is monochrome and determine a coloration of the pixel as a whole via a color addition or color subtraction.

Individualizing is a pattern when it is unique to a person or a person

Is an object or a group of persons or objects from a large totality of persons or objects. For example, a code individualizing a group of persons within the total population of a country is the city of residence. An individualizing for a person code, for example, the number of the identity card or passport photo. One for a group of bills within the total amount of bills

individualizing code is the value. Individualizing for a banknote is the serial number. Non-individualizing is a pattern that is identical for all elements of an entity. For bills this is for example a coat of arms, which is printed on all banknotes.

A basic pattern is an arrangement of monochromatic areas or sub-areas thereof, which, with suitable modification of the color of the areas or

Subareas allow a mark of a multicolor pattern over it.

Colored is an entity that causes a color impression when viewed by a human. Multicolor is an entity that produces at least two distinguishable color impressions. Monochrome, on the other hand, is an entity when it produces a single color impression.

Colorants are all entities that are responsible for causing a

Color impression of an emission or absorption of light in the visible

Wavelength range are responsible. The light of a Planckian radiator, which produces a continuous spectrum in the visible wavelength range, is regarded here as white light. Natural sunlight is an example of white light.

Preferred embodiments

In particular, a method for multi-color marking of value or

Security documents created, comprising the steps:

Providing a document body comprising areas of different colors, each area being monochromatic;

Providing a marking device, which at least one laser light source for generating laser light and

a light guide device coupled to the laser light source so that a focus of the laser light of the laser light source is controllably positionable on or in the document body of the value or security document;

iterative targeted positioning of the focus on or in the document body and

Injecting the laser light to selectively locally change the color of one or more of the areas, so that the document body subsequently a multicolor

Produces a color impression when irradiated with white light for a human observer,

wherein the laser light used for marking is irradiated by means of short or ultrashort laser pulses having a plus duration of less than 100 ps or less than 10 ps.

A marking device for multi-colored marking of value or

Security documents thus includes:

at least one laser light source and

a light guide device coupled to the laser light source such that

Laser light of the laser light source can be positioned in a controlled manner on a value or security document,

wherein the laser light source is a short pulse laser source or ultrashort pulse laser source that generates laser pulses having a pulse duration of less than 100 ps or less than 10 ps. In addition to purely optical focusing, the achievable resolution in the method according to the prior art with respect to the marking produced is usually limited by the fact that the interaction between the laser light and the value or Security document based on thermal effects. This can be explained by the

Avoid using laser light from short-circuit lasers.

Iterative targeted positioning of the focus on or in the document body and

Irradiation of the laser light comprises both the repeated irradiation of light several times successively at the same focus position relative to the document body and a repeated irradiation of light, wherein in each case the position of the focus relative to the material to the surface of the document body and / or perpendicular to the surface of the document body varies becomes. A variation of the focus position perpendicular to the document surface alters a selection of a plane parallel to the surface of the document body in which the focus is positioned.

An advantage of using short pulse laser light is that with this

Laser light intensity densities are achievable that include nonlinear optical

Interactions can be triggered. This makes it possible, for example, to produce markings with a higher resolution, since thermal

Interaction processes, which are always associated with a dissipation of heat into surrounding areas and thereby cause a resolution limitation, can be avoided.

An embodiment of the invention thus provides that the local change in the color of a region is made via a non-linear interaction with the irradiated laser light.

In order to create a multicolored color impression, for example to mark a full-color colored passport image in a security document, in one embodiment at least three regions of different colors are provided together in a basic pattern of nested sub-regions or arranged in the basic pattern when provided. The at least three areas can thus be divided into many, usually regularly arranged sub-areas. As belonging to a region, the subregions having the same color are considered. The subregions may be two-dimensional area or three-dimensional volumes. For example, such a basic pattern can be printed by printing using different inks on a substrate layer. Likewise, it is also possible in a further embodiment, the sub-areas on different substrate layers so imprint that the sub-areas of the various substrate layers from which the document body by stacking the substrate layers and subsequent assembly, for example in a lamination process, each other, with respect to a viewing direction parallel to the lamination direction, not or substantially not overlap.

In order to produce a desired color impression, an exact positioning of the laser light on or in the document body is necessary to selectively correct the individual subregions with regard to their color. As a result, a falsification or marking with not provided hardware is made much more difficult.

Particularly preferably, the document body comprises at least three areas

different colors, each having a base color of a color system, which spans a multi-color gamut. Thus, with a suitable choice of the primary colors in the document information can be encoded, which can use almost the entire human-perceivable color space.

In a preferred embodiment, the relative to a normal of a

Surface of the document body not or at least not completely overlapping sub-areas arranged so that they enter before marking

Bayerpattern represent. This makes it possible to mark a pattern composed of regularly arranged pixels which, with regard to the usable colors, can use almost the entire perceptible color space. With regard to their assignment to the at least three regions and the arrangement relative to one another, the subregions are optimally adapted to the sensitivity of the human eye, so that over a maximum of four markings of subregions, one image pixel each can be generated which produces any color impression from the gamut spanned by the primary colors causes.

In order to be able to store the color information in a plane of the value or security document via the markings, in one embodiment this is or

Bayerpattern printed on a substrate layer surface. This is or is preferably formed as an inner substrate layer surface, so that a manipulation is difficult. According to a further embodiment, the colored areas in the form of layers which overlap one another in a planar manner are introduced into the document body or are thus introduced during the provision.

In one embodiment, the markings are made by removing material. Here, cavities are introduced into the document body from the surface. A depth of the cavities in the document body determines which

Color impression on the document body at the location of the cavity is formed. By using short pulse laser light or ultrashort pulsed laser light, the cavities can be formed so close to each other that the remaining material does not cause color degradation of the entire marked pattern as in the prior art. Because the edge surfaces of the cavities can be formed smoothly and perpendicularly to the surface of the document body (with perpendicular irradiation of the laser light), web widths of the document body remaining between adjacent cavities can be minimized. As a result, intense color patterns can be generated which are not impaired by the color of the web areas.

In order to achieve a high localization of the individual markings, the

Focusing the laser light in an embodiment made such that a diameter of an interaction region of the non-linear interaction of a laser pulse in an image plane perceived by the human user in the

Order of magnitude of smaller ^" Ι ΟΟμηι, more preferably less than 20μηι, am

most preferred is in the order of 5 to 15 μηι.

The local change in the color of a region can be achieved by changing the colorant causing the color by means of the non-linear interaction

be made.

Particularly short laser pulses with pulse durations in the range of less than 10 can picoseconds, preferably in the range of 100 femtoseconds to 10

Picoseconds, with a fiber laser. Compared with other solid state lasers fiber lasers have the advantage that they can be constructed very compact and have a high electro-optical efficiency. In addition, fiber lasers are much more modest in terms of adjustment and handling than most known solid state lasers. An advantage of using short laser pulses with pulse durations of less than 100 picoseconds, preferably less than 10 picoseconds, is that very precise spatial confinement of the zone of interaction between the laser light and the material of the asset or security document is achievable when non-linear optical interaction effects can be used to form the label. A preferred embodiment of the method therefore provides that the marking via a non-linear optical effect in the value or

Security document is triggered.

In an embodiment, it is provided that the light-guiding device comprises a relative to the value and / or security document movably mounted optical fiber, which is coupled to at least one drive means so that the laser light via a movement of an exit surface of the optical fiber in a positioning plane relative to the value and / or security document laterally on the value or

Security document is positionable. The laser light of the laser light source is thus guided by means of an optical fiber and a positioning of the laser light on the value or security document to be marked is effected by moving the

Exit surface of the optical fiber relative to the value or security document.

Compared to the prior art, there is the advantage that the laser light used for marking with a suitable orientation of the positioning plane relative to a surface of the security document, preferably parallel thereto, each at the same angle, preferably perpendicular, to the value and / or

Security document incident and beyond a path length of the traveled light path is the same regardless of the illuminated lateral position on the security and / or security document. This makes it possible to focus the laser light used stronger and yet to use an identical focus extension at the marking at all lateral positions of the value or security document. Problems that are known due to a slightly different direction of irradiation in the guide devices of the prior art, can thus be avoided.

To achieve a high resolution in the marking, a good focus is advantageous. For this purpose, a focusing optics can be used. Preferably, a focusing optics, if used, with the respective exit surface of the Pairing optical fiber. This means that the focusing optics by means of

Drive device is moved together with the exit surface of the optical fiber. The advantage is that the light path through the focusing optics is the same in each case, regardless of the position on or in the value or security document that is being marked.

Different implementations are possible in order to specifically set a focus position in the value or security document.

In one embodiment, the focusing takes place by means of the Kerr effect. In this case, the focal length of the material of the focusing lens changes due to the non-linear interaction of the electromagnetic radiation with the material of the lens. The focal length of the lens is inversely proportional to the intensity of the lens

electromagnetic radiation in a gau ßförmigen radiation profile.

In an embodiment in which the light guide is performed by means of an optical fiber, it is provided that in addition to the movement in the positioning plane, which is usually oriented parallel to a surface of a plane security document, a movement of the exit surface of the optical fiber is possible to vary a light path between the exit surface and a surface of the document. This can be used to vary a focus position within the value or security document. Such a change in direction can be achieved, for example, in one embodiment in that the exit surface, from which the laser light is rectilinearly guided on the document surface, in addition to the movement in the positioning plane, which is parallel to the surface of the value or security document, perpendicular to the Positioning level or the surface of the value or security document is movable.

In other embodiments, in which the exit surface is moved, for example together with an imaging and / or focusing optics in the positioning plane to the emerging laser light laterally on the surface of the value or

Positioning a security document can change the light path

For example, in some embodiments can be achieved in that the exit surface of the optical waveguide in addition to the elements of the imaging and / or focusing optics, such as a deflection mirror, in the positioning plane is relatively movable. Thus, on the one hand, a positioning laterally on the document via a movement of the exit surface together with the imaging and / or focusing optics is possible and additionally by a relative movement of the

Exit surface relative to the imaging and / or focusing optics in the positioning plane, a change in the focus position perpendicular to the surface of the value or

Security document possible.

In a further embodiment, the focusing optics consists of a

piezoelectric material. By applying tension, the material can be deformed and thus the focal length of the material can be adjusted.

In a preferred embodiment, the laser light source is integrated in the optical fiber. As a result, any coupling losses are reduced in the coupling into the fiber. Thus, a compact and simple construction is possible. Across from

Solid-state lasers, for example Ti: sapphire lasers, fiber laser systems require no expensive cooling and achieve a high electro-optical efficiency. Furthermore, laser light can be transmitted via a parametric tuning with the same hardware

different wavelengths are generated. This is effective with fiber lasers.

In order to enable a faster marking of the value or security document, it is provided in a further development of the invention that the light guiding device comprises at least one further movable, preferably even more, further movably mounted optical fibers. This makes it possible, at the same time at several points or at the same time with different wavelengths of light to attach a mark on the security or security document or in the value or

To introduce security document. If different wavelengths of light are used, then each optical fiber can be provided with a focusing optics adapted to the corresponding wavelength of light. It should be noted that with pulse durations of more than 10 ps it is still possible to speak of a defined wavelength. At pulse lengths shorter than 10 ps, the spread due to the Heisenberg uncertainty principle is significant. Thus, the blur at a pulse of 10 ps is about 0.41 meV, which corresponds to about 0.12 nm at a wavelength of 620 nm (2 eV). At pulse durations of 10 fs, the blur is about 0.41 eV, which means at a wavelength of 620 nm (2 eV) that the bandwidth is at least 125 nm. In a preferred embodiment of the invention, the exit surface of the at least one optical fiber is positionable relative to the at least one further optical fiber or optionally relative to the plurality of exit surfaces of the plurality of optical fibers in the positioning plane. Particularly preferred are the plurality

Optical fibers or their exit surfaces in the positioning plane individually driven and positioned relative to each other. It goes without saying for the person skilled in the art that there are mechanical residual actions since the optical fibers can not penetrate one another and thus can not be arranged at one and the same position at the same time.

If a plurality of optical fibers are present, then the focus position within the value or security document along a normal to the surface of the value or security document can be set individually for the latter in one embodiment. This can be targeted markings in different levels or layers, from which the value or security document is joined, are introduced. Preferably, this is controlled possible.

The features of the method according to the invention have the same advantages as the corresponding features of the marking device according to the invention.

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 marking device for value or

Security documents;

FIG. 2 shows a schematic representation of a document body for introducing a colored marking; FIG.

3 is a schematic representation of a marked document body;

4 is a schematic representation of a beam profile in focus;

Fig. 5 is a schematic representation of a basic pattern; and Fig. 6 shows another embodiment of a marking device.

FIG. 1 schematically shows a marking device 1 for the permanent marking of a value or security document 2. The value document 2 is on a

Bracket 3 is arranged. This can be supplied to the value or security document 2 by means of a transport device 4 and / or removed from it. In some embodiments, it is possible that the transport device 4 forms the holder 3. The person skilled in various devices for transporting value or security documents are known. In general, the marking of the value or security document 2 is carried out after this is completed except for the mark still to be attached. However, it is also possible to make the marking before the value or security document 2 is completely finished, for example, before it is separated from a sheet or a strip.

The marking device 1 comprises a laser light source 5. The laser light source 5 is designed to generate laser light 6. The laser light source 5 is a pulsed light source. For example, it may be a solid state laser, e.g. a Ti: sapphire laser, act. In order to mark the value or security document 2, the laser light 6 must be aimed at the value or security document 2, i. on the surface 7 or inside the value or security document 2, are positioned. For this purpose, a light guide device 8 is provided. In the embodiment described here, the light-guiding device 8 comprises an optical fiber 9, into which the laser light 6 is coupled. An exit surface 10 of the optical fiber 9 is moved in a positioning plane 1 1. The positioning plane 1 1 is formed parallel to the surface 7 of the value or security document 2 in a preferred embodiment. In order to move or position the exit surface 10 in the positioning plane 1 1, the optical fiber 9 is coupled to a drive device 12. The drive device 12 comprises in the illustrated embodiment an X-axis actuator 13, a Y-axis actuator 14 and a Z-axis actuator 15. These are connected and aligned so that the X-axis actuator movement of the exit surface 10 of the optical fiber 9 parallel to a X-axis 16, the Y-axis actuator 14 parallel to a Y-axis 17 and the Z-axis actuator 15 parallel to a Z-axis 18 causes. It should be noted that a movement parallel to the Z-axis causes a change in the positioning plane 1 1. About the

Drive device 12, it is thus possible, a position of a focal point 19 of the exit from the exit surface 10 laser light 6 'along a normal to the surface. 7 of the value or security document 2. A movement of

On the other hand, the exit surface 10 in the positioning plane 1 1 effects a lateral alignment and positioning of the laser light 6 'emerging from the exit surface 10 or the focal point 19 formed thereof. It should be noted that other embodiments may have and use differently configured light guiding devices.

In some embodiments, it is provided that an imaging and / or focusing optics 20 is coupled to the exit surface 10 of the optical fiber 9. This is moved with the exit surface 10 of the optical fiber. In some embodiments, the exit surface 10 of the optical fiber is configured so that the exiting laser light 6 'is focused and no or supplemental focusing optics are necessary.

About the introduced at the respective position in the value or security document amount of energy, which can be varied for example via a pulse intensity or a number of introduced at the same position light pulses, the color of the mark or its color impression caused regulated. Via the drive device 12 it is possible to make a marking vectorially (but broken down into individual pixels (marking points)) or in a grid.

A distance 27 of the positioning plane 1 1 from the surface 7 or the value or security document 2 need not be varied in some applications in the marking. Then, a positioning device 8 which comprises only one X-axis actuator 13 and one Y-axis actuator 14 is sufficient. It is understood by those skilled in the art that for the positioning of the exit surface 10 of the optical fiber 9 in the

Positioning level 1 1 also a set of actuators can be used, which no

Moving parallel to the coordinate axes cause, but in cooperation are able to position the exit surface 10 in the positioning plane 1 1 laterally at different locations.

It is understood by those skilled in the art that the light exit surface 10 in the

Positioning level 1 1 must not be able to be positioned in all embodiments so that all points on the surface of the document with the exiting laser light 6 'can be illuminated. The laser light need only be positionable to those positions on the asset or security document at which markings

should be made. Is only a limited range of value or Security document provided for a mark, as well as an adapted to this area positioning range 26, in which the exit surface 10 of the optical fiber 9 is positioned.

FIG. 2 shows an exemplary embodiment of a document body 40 of a value or security document 2 which is suitable for introducing a colored marking. The document body 40 is formed as a lamination body. In the manufacture, a carrier foil 41, a black foil 42, a blue foil 43, a green foil 44, a red foil 45 and a clear, i.e. transparent cover sheet 46 stacked one above the other. These are then subsequently in one

Lamination process using heat and pressure together to the monolithic document body 40 assembled. Preferably, the films 41-46 are all made of the same thermoplastic material, such as polycarbonate or polyvinylchloride. Additional security elements may be inserted between the foils 41 to 46. In addition, individual or all foils may be printed.

The black film 42, the blue film 43, the green film 44, and the red film 45 each represent monochrome areas each having a different color from the others. Blue, red, green represent the basic colors of an RGB color system. The gamut of the RGB color system makes it possible to display full-color objects. In order to be able to represent black in a simple manner, a black foil is additionally provided.

For example, using a cyan yellow magenta (black) color system (CYM (K) color system) one would use a cyan film instead of the blue film 43, a yellow film instead of the green film 44 and a yellow film instead of the red film 45

use magenta foil.

The order of the slides can also be chosen differently. Preferably, the films 41-45 are opaque. As a result, a color space comparable to the normal printing systems is clamped, since only the uppermost color layer is always visible. As a result, standard systems can be used to optimize the color space. In a transparent embodiment of the films 41 -45 is a corresponding

Adjustment of the colors necessary, since in this case all remaining color layers characterize the color impression. As a result, the generation but also the falsification or adjustment is much more difficult.

The introduction of a colored marking will now be explained by way of example with reference to FIG. Schematically, a document body 40 is shown similar to that of FIG. The same technical features are identified by the same reference numerals throughout the application. The document body 40 contains a barrier film 47 instead of the cover film 46 over the red film 45. This is, for example, opaque and white. Over the barrier film 47, a protective film 48 is arranged, which after the colored

Marking, for example, is laminated.

Before introducing a mark, the document body 40 appears white when viewed under natural daylight (white light). By means of short or ultrashort laser light pulses, cavities 51 - 54 are introduced into the different films 47, 45,

44, 43 introduced. A depth of the cavities 51 - 54 defines which color impression a surface 7 has locally at the location / position of the respective cavity 51 - 54. The cavities 51 and 54 in each case extend completely through the white barrier film and into the red film 45. Thus, a red color impression is imparted locally. In the cavity 52 and the red film 45 is completely penetrated. The cavity 52 ends in the green foil, so that locally a green color impression is mediated. The cavity 53 terminates in the blue film 43. All overlying films are completely pierced. It is generated locally a blue color impression.

The depth of the cavity can be selected via a choice of the energy deposited via one or more short or ultrashort laser pulses, a choice of the depth of focus, an adaptation of the wavelength of the laser pulse (s) to the color of the respective film to be removed.

45, 47 can be selectively varied.

A cross-sectional shape of the cavities can be controlled by a choice of beam profile as well as a sidewall shape of the cavities. Factors influencing this are the depth of focus and the defocusing of the laser beam and optionally an im

Document material existing Kerr effect, which is an additional

Focusing or defocusing of the beam may result. Due to the short pulse duration and the achievable high light intensities nonlinear interactions can be exploited, so that in the

Document body 40 no thermal effects occur, which lead to a dissipation of energy in the document body and in this case to less precisely defined Kavitätsquerschnittsformen. In particular, the possibility cavities with almost perpendicular to the surface 7 of the value or security document 2 and des

Make document body 40 oriented side walls 55, allows wells specifically introduced at short intervals 56,57 in the document body 40.

Remaining webs 58 between the cavities 52-54 are thus viewed from the surface 7 of area small, so that a high density of points and thus resolution of the information shown on the marks is possible. In addition, the remaining lands affect a color intensity less than in the prior art. It is understood that for a macroscopic flat color impression of a viewer, the color addition or color subtraction of the individual cavities 51-54

caused local color impressions are responsible.

The subsequently applied protective film 48 protects the cavities 51 -54 during use of the document body 40 as a value or security document 2. Also, introducing further cavities to falsify the value or security document 2 is at least made more difficult because it also damages the protective film 48 would effect.

If non-linear interactions are exploited, the shape of the beam profile can be used to achieve a focus which is smaller than the focusing of the laser light. This will be explained below with reference to FIG. 4.

The individual components of the marking device are controlled by a controller 22, so that the marking is carried out automatically. The controller 22 is only supplied with data containing the pattern for the mark, so that the corresponding areas of the value or security document 2 are irradiated with a corresponding laser light intensity to effect the corresponding marking in the value or security document 2.

The embodiment of FIG. 1 is characterized in that the laser light 6 as a pulsed laser light with short pulse durations of less than 100 ps, preferably of less than 10 ps is generated. This is an exploitation of non-linear optical effects for introducing the markings on or in the value or

Security document possible.

By using the optical fiber 9 for guiding the laser light 6 'onto or into the value or security document 2, a path length 27 between the

Light guide device 8 and the value or security document 2 are kept low. This can be selected in the range from contact to a few cm, preferably 0.2 to 10 mm. This makes it possible to form the beam guide strongly divergent and to focus sharply. Both across the beam direction

(Propagation direction) and along the beam direction can thus be achieved a very narrow focus.

With suitably chosen intensity and suitably chosen beam profile, a nonlinear interaction is achieved only in a "core region" of the beam of the laser light in the focus, whereby an even closer light focusing is achieved compared to the geometric light focusing

Direction of irradiation of the laser light 6 'as well as longitudinally, that is in

Propagation direction of the laser light 6 'improved resolution can be achieved when marking. For example, micro-writing can be realized with a character size in the range of a few micrometers.

In Fig. 4, a so-called beam profile 61 in focus is shown schematically. A light intensity I is plotted against the position r transversely to the propagation direction (z-direction in FIG. 1), (r is chosen, for example, parallel to the x-axis according to FIG. 1). It is assumed here that a beam profile 61 of the laser light 6 1 (according to FIG. 1) in the focus 19 (according to FIG. 1) has a Gaussian profile. Since nonlinear interactions are dependent on the square I ² 62 of the intensity I of the laser light, that is to say a so-called I ² dependency, the non-linear one is found at a suitably chosen pulse intensity

Interaction takes place only in the core region 63 of the steel profile, in which the square I ² 62 the intensity I of the beam profile 61 exceeds a threshold 64. As a result, the focal extent of the marking is determined by an extension 65 of the core region 63 and not by the extent 66 of the focus 19 of the laser light 6 ', which corresponds to the extent of the beam profile 61. In another embodiment, the regions having different colors are introduced into the document body in the form of subregions. The sub-areas are arranged so that these sub-areas at a

View a surface of the document body form a predetermined pattern. For example, a Bayer pattern 81 can be used as the given pattern, which is shown by way of example in section in FIG. 5. For each colored pixel 82 of the information to be marked, four subregions 83 are provided in each case. A sub-area 83-r is red and a sub-area 83-b is blue, two sub-areas 83-g1, 83-g2 are green.

The individual subregions 83 are preferably arranged in a plane of the document body parallel to a surface of the document body. For example, the subregions 83 may be printed on a surface. Likewise, it is possible for the subregions 83 to be printed on different surfaces of foils that are gathered and assembled such that the individual ones

Subareas are arranged in the register and give the given pattern.

Colored marking is accomplished by modifying the subregions 83 for their color by means of short or ultrashort laser pulses of less than 100 ps or less than 10 ps, preferably 100 fs-10 ps. The sizes and the distances of the individual subregions 83 can be selected such that they are smaller than the focus size of the laser light pulses. A targeted modification of the colourfulness, for example by removing the ink causing the colouration or by "destroying" the colourant-causing pigments in the corresponding subregion, can be achieved by utilizing non-linear interactions the optical focusing of the laser light to obtain and exploit enhanced focusing of the interaction region.

Thus, for example, information in the form of micro-writing can be color-coded into a value or security document for individualizing it.

It will be understood by those skilled in the art that alternative patterns to a Bayer pattern may also be used, allowing for color addition or color subtraction appropriate modification of the subregions can achieve a variety of different color impressions.

In Fig. 6, another embodiment of a marking device 1 is shown schematically. Technically equivalent features are provided with identical reference numerals. The illustrated embodiment differs from that of FIG. 1 in that the light guide device 8 in this embodiment two

Optical fibers 9, 9 'comprises. These are respectively coupled to a drive device 8 or 8 ', which are formed analogously to the drive device 8 according to FIG. This embodiment offers the advantage that the value or security document 2 can be marked simultaneously or quasi simultaneously at several locations.

The laser light source 5 is shown schematically in this embodiment as a fiber laser 23 with a seed laser 24 and an amplifier ring 25. It will be understood by those skilled in the art that another source of laser light may be used with it

Embodiment can be used. Likewise, a fiber laser 23 as

Laser light source 5 are used in the embodiment of FIG. 1.

LIST OF REFERENCE NUMBERS

1 marking device

2 value or security document

3 bracket

4 transport device

5 laser light source

6, 6 'laser light

7 surface

8, 8 'light guide device

9, 9 'optical fiber

10, 10 'exit surface

1 1 positioning plane

12, 12 'drive device

13, 13 'X-axis actuator

14, 14 'Y-axis actuator

15, 15 'Z-axis actuator

16 X axis

17 Y-axis

18 Z axis

19 focus point

20 Imaging and / or focusing optics

22 control

23 fiber lasers

24 seed lasers

25 amplifier ring

26 positioning range

27 distance

40 document bodies

41 carrier film

42 black foil

43 blue foil

44 green foil

45 red foil

46 cover sheet barrier film

protector

-54 cavities

Side wall

, 57 distances

Stege

beam profile

Square of intensity (I ² )

core area

threshold

Extension of the core area

Extent of focus

Bayer pattern

Pixel (of information)

subfield

-r subrange (red)

-b subrange (blue)

-g1, 83-g2 subrange (green)

Claims

claims

1 . Method for multi-colored marking of value or security documents

(2) comprising the steps:

Providing a document body (40) comprising regions of different colors, wherein the individual areas are each monochrome;

Providing a marking device, which at least one

Laser light source (5) for generating laser light (6) and

a light guide device (8, 8 '), which is coupled to the at least one laser light source (5), so that a focus (19) of the laser light (6) of the laser light source (5) on or in the document body (40) of the value or security document (2) is positionally controlled;

iterative targeted positioning of the focus (19) on or in the

Document body (409 and irradiation of the laser light (6 ') to selectively locally change the color of one or more of the areas, so that the

Document body (40) then causes a multicolor color impression upon irradiation with white light for a human observer, characterized in that

the laser light (6) is irradiated by means of short or ultrashort laser pulses having a plus duration of less than 100 ps or less than 10 ps.

2. The method according to claim 1, characterized in that the colored

Areas in the form of layers that overlap one another in the surface

Document body (40) are introduced or introduced when providing.

3. The method according to claim 1 or 2, characterized in that the

Document body (40) comprises at least three areas of different colors, each having a base color of a color system comprising a multi-color gamut.

4. The method according to claim 3, characterized in that the at least three

Areas of different colors in a pattern

nested subareas are provided or arranged upon deployment.

5. The method according to claim 4, characterized in that the pattern is designed as Bayerpattern (81) or is.

6. The method according to any one of claims 1 to 5, characterized in that the local change in the color of a region via a non-linear interaction with the irradiated laser light (6 ') is made.

7. The method according to any one of claims 1 to 6, characterized in that the local change in the color of a region is made by changing the color causing colorant by means of the non-linear interaction.

8. The method according to any one of claims 1 to 7, characterized in that the

Focusing of the laser light is made so that a diameter of an interaction region of the non-linear interaction of a laser pulse in an image plane perceived by the human user in the order of magnitude of smaller ^" Ι ΟΟμηι, more preferably less than 20μηι.

9. marking device (1) for color marking of value or

Security documents (29 comprising

at least one laser light source (5) and

a light guide device (8) which is coupled to the laser light source, so that laser light (6 ') of the laser light source (5) can be positioned in a controlled manner on or in the document body of the value or security document (2),

characterized in that

the laser light source (5) is a short pulse laser source which generates laser pulses with a pulse duration of less than 100 ps.