EP1610956B1 - Method for generating an item of information, supporting body, inside of which the item of information is generated, and use of a supporting body of this type - Google Patents

Abstract

A method for generating an item of information in a supporting body should, by using simple means, produce an item of information that is stable over a long period of time and, in particular, with regard to light and moisture. To this end, the reaction conditions for a number of reactants contained in the supporting body are set in a localized partial area of the supporting body by laser irradiation, whereby the reaction conditions set are those that cause the reactants to enter into a synthesis reaction.

Description

The invention relates to a method for generating information. It further relates to a carrier body, in which the information is generated, as well as a use of such a carrier body.

To achieve colored information, photochemical reactions are directly or indirectly part of everyday life. Traditional silver halide photography processes involve either wet chemical operations, such as developing and fixing in respective baths, or working with organic dye systems, such as e.g. Polaroid instant images, which are usually not lightfast.

In the course of semiconductor development but also in the computer-aided creation of prototypes (rapid prototyping, rapid tooling), a variety of so-called photoresist materials or photoprepolymer has established on the market (Ullmann's Encyclopedia of Industrial Chemistry, Sixth Edition, 2002 Electronic Release, keyword photoresists). In the broadest sense, these are so-called prepolymers which polymerize, crosslink or harden on the basis of photochemical reactions and only in a subsequent step by leaching with solvents, as in photolithography, or with changes in the z coordinate, as in rapid prototyping , as separate information from the background, written in the xy direction.

In order to achieve a comparatively high spatial resolution and thus also a higher data and information density in the abovementioned methods, lasers are generally used. Conventional laser marking methods find a large field of application in the production of badges, driver's licenses, bank cards, credit cards or the like made of plastic.

From DE 29 07 004 C2 is known to apply visually readable information on ID cards by means of laser radiation. In this case, the information becomes visible through charring and / or carbonization of the plastic material, the information becoming black or gray against a different colored background, e.g. opaque or transparent, takes off. Other colors can not be created with it. In this case, laser marking is safer than other labeling methods against counterfeiting or manipulation, because it can be retrofitted in internal layers.

Moreover, it is also known to engrave by means of laser radiation, in particular it is possible to remove individual layers of a multilayer card body locally. This circumstance is exploited according to DE 30 48 733 C2 to apply different colored information on ID cards. In this case, a multilayer card body is used whose layers are differently colored. By local ablation of individual layers by laser radiation, the underlying differently colored layer becomes visible. However, this method for labeling card-shaped data carriers may have the disadvantage that the surface of the data carrier is damaged by the removal.

From DE 44 17 343 A1. It is known to incorporate a monochrome component and / or gray and black component of an image component into an identification card by laser technology and to apply it congruently with respect to the image to a complementary color image component in particular in the thermal transfer process. In the latter, dot-shaped electrodes of a thermal printer line are heated electrically controlled so that the color layer of a color film or multicolour color film introduced between the thermal printer line and the cover layer melts and / or evaporates pointwise and is deposited on the cover layer. The different processing of the card with highly technical devices produces a high color depth, which makes forgery by means of common Farbkopier- and color printing techniques, but requires a complex apparatus method.

DE 100 53 264 A discloses a wavelength-selective bleaching or destruction of individual colorants, so that when a plurality of individual colorants destroyed in this way is created by subtractive color mixing, a new color is formed.

WO 02/068205 A provides an elimination reaction for producing a contrast and is limited to products and organic substances to be consumed.

WO 01/09230 A discloses a process for the photochemical monomolecular blackening of a thermoplastic elastomeric material by the incorporation of corresponding pigments into the elastomer.

The document WO 02/096662 A is a (CD) writing method in which the optical density of a color layer is changed.

DE 199 55 383 A1 describes a method for applying colored information to an object by means of laser radiation having at least two different wavelengths, wherein the color of the layer can be adjusted by wavelength-selective bleaching of individual organic pigments as a result of subtractive color mixing.

DE 100 11 486 A1 also describes a card-shaped data carrier and a method for producing the same, which enables the application of colored information by means of the laser processing without damaging the surface of the data carrier. In this case, a layer is completely bleached locally by the laser radiation, so that the layer alone is at least almost transparent in the laser writing spot. In this way, an original black, gray or dark brown spot red, blue or green can be adjusted, depending on which of the laser-sensitive layers in the sandwich construction are bleached.

The invention has for its object to provide a method for generating information in and / or on a support body, which has a particularly high relative to light and moisture particularly high long-term stability by simple means. Furthermore, a carrier body which is particularly suitable for this method should be provided, and a use of such a carrier body should be specified.

With regard to the method, this object is achieved according to the invention by setting for a number of in and / or on the carrier body starting materials in a localized portion of the carrier body by laser irradiation those reaction conditions that cause the starting materials to a synthesis reaction.

The invention is based on the consideration that in previous systems, the long-term stability of the information is limited, inter alia, that color conversion reactions are continued uncontrolled even without targeted and intentional activation, eg by irradiated sunlight. This activation can be done by statistical suggestions of a commonly used dissociation reaction, as in a dissociation reaction in which only one starting material is required, the necessary reaction conditions for the decomposition of the molecule into simpler molecules, atoms, ions or radicals are relatively easily accessible. Thus, for example, a fading by photochemical decomposition, which can lead to the destruction of both the information and the carrier body occur. The concept for generating long-term information therefore represents a departure from such simple decolorization processes. Increasing the long-term stability of the information can be achieved precisely by consistently reducing the probability of subsequent, statistically triggered conversion processes. This can be achieved by a targeted increase in the complexity of the reaction reaction used with correspondingly higher, more difficult to fulfill reaction conditions. For a correspondingly increased complexity of the reaction processes, therefore, the use of reaction types is provided, which are based on the use of a plurality of starting materials or other complex reaction parameters. The generation of information resistant to light and moisture is achieved instead of destructive processes or dissociation by synthetic processes.

As such synthesis reactions are preferably additions, eliminations, substitutions and in particular redox and complex formation reactions into consideration. In addition, atoms or atomic groups are attached to a multiple bond. When eliminated as an inversion of addition, atoms or groups of atoms are separated from one molecule without others taking their place at the same time. The substitution is characterized by the replacement of an atom or an atomic group in a molecule by other atoms or groups of atoms, whereby a covalent bond is dissolved with one partner and then one is linked with another partner. The redox reaction is characterized by the electron donation of one partner (reducing agent) and the electron uptake of the other partner (oxidizing agent). In complex formation reactions, a central atom or ion is surrounded by a plurality of other atoms, ions or molecules, the so-called ligands, in a spatially regular arrangement.

With these synthetic processes, comparatively demanding or complex requirements are imposed on the reaction conditions and on the reactants and.

As reaction conditions in particular a sufficiently high reaction temperature, a release of reactive starting materials or activated molecular species in sufficient for the reaction number and / or a sufficiently high particle mobility of the reactants have a special significance. These reaction conditions can be accomplished by introducing a thermal energy in a spatially resolved manner by laser light, which provides the activation energy of the process. Due to the thermal energy, the mobility of the starting materials in or on the carrier body is improved and thus the reaction probability is increased so much that a sufficient reaction conversion is achieved. In addition, irradiation with laser light makes it possible to break up reaction-inhibiting environments and thus make the starting materials available as reactants in the first place.

Without energy supply, the starting materials stored in the carrier body should not be able to cause a property or substance change to produce a durable information. Their statistical probability of reaction should therefore be lowered, for example, with respect to the reactants of a bleaching process. For this, under normal environmental conditions, neither the activation energy necessary to produce reactive molecular species from the starting materials should be achieved, nor should the reactive molecular species be present in sufficient local concentration under normal conditions to initiate a reaction or even complete reaction conversion to reach. Another condition for suitable starting materials is an inertness relative to the carrier body itself, so that it is not permanently changed by the starting materials and thereby possibly damaged or rendered useless. As starting materials stored in the carrier, it is therefore possible in principle to consider mixtures or compounds of all elements of the Periodic Table which are suitable for such a "robust" use. In particular, these criteria are preferably fulfilled by selected inorganic substance mixtures, since these migrate comparatively little in the carrier body and reactions under material or property change usually only at high temperatures of several hundred degrees Celsius, such as inside a Bunsenbrennerflamme show.

The change in their absorption properties with respect to the wavelengths in the ultraviolet to infrared range is expediently suitable for the detection of the property or substance change of the starting materials caused by laser irradiation. For a particularly simple detection, the starting materials are advantageously chosen such that they are caused to undergo a synthesis reaction with color change. Thus, preferably a colored information is generated.

For one or more colored information or information selected as needed, the starting materials of the synthesis reactions of different color changes are preferably selected such that the product of the respective synthesis reaction is assigned to a respective primary color of a CMYK color scheme for cyan, magenta, yellow and contrast or black. This can be produced with a suitable combination mono or mixed colors.

In order to allow graphically particularly varied color patterns and variations in the carrier body, the starting materials of synthesis reactions of different color changes are preferably kept in separate volume segments in the carrier body.

For generating differently colored information and information in a carrier body with a comparatively high color depth, in particular also with regard to a particularly reliable laser marking compared to counterfeiting and manipulation, in addition to the outer color design of this carrier body also an inner color design is appropriate. Therefore, the different color reactions associated with starting materials are preferably kept in separate layers in the carrier body.

In order to prevent a premature reaction of the starting materials without excitation by laser irradiation, it is expedient to provide a protective device or measure which suppresses this reaction. For this reason, preferably at least one of the starting materials is kept encapsulated in the carrier body, wherein the encapsulation is advantageously chosen such that it is broken up by the laser irradiation and releases the relevant starting material as a reaction partner. For this, the encapsulation is preferably designed such that it absorbs the laser radiation itself. This ensures temporally and locally targeted generation of information.

For targeted focusing of the laser irradiation directly on at least one starting material, in particular, if this alone is not or only insufficiently suitable for the absorption of the laser radiation, or for reducing the required laser energy, preferably the laser irradiation absorbing auxiliary substances or layers are embedded in the carrier body. As absorbent adjuvants, for example, a mica pigment, which is commercially available under the name "Iriodin" or "Mica", i.a. into consideration. As a result, the laser light irradiated on the excipient is transferred via interference or mirror effects to the selected starting material. This leads at this point to a local temperature increase, a so-called hot spot or a hot spot, and thus to an excitation of at least one starting material with usually at least one other starting material, so that they interact and enter into a synthesis reaction.

In order to reduce the activation energy of the reactants, preferably catalytically active particles are embedded in the carrier body. This makes it possible, depending on the selected starting materials, to use a comparatively low laser energy or even a comparatively low-power laser. The catalytic elements can originate in particular from the 8th subgroup, the so-called platinum metals. Finely divided platinum, rhodium, palladium or mixtures thereof can, in particular, catalyze redox reactions analogously to their use in catalytic converters. Also conceivable would be a decomposition of a platinum complex, such as a decomplexation of the orange-red (CH ₃ ) ₃ Ptl. On the one hand elemental platinum could be obtained as a catalyst by a decomposition of the (CH ₃ ) ₃ Ptl or at higher concentration even generate blackening due to finely divided platinum.

For a particularly simple generation of information in a carrier body with a low equipment and technical effort and for a high spatial resolution and thus to achieve a higher data and information density, are preferably all for labeling documents commercially available laser with emissions from UV to For example, with emissions of 190 nm for a photolithography or with emissions of 10 μm for a packaging inscription with a CO ₂ laser. In a particularly advantageous embodiment of the lettering, an Nd: YAG laser with an emission of 1064 nm is used.

In a particularly advantageous embodiment, the laser irradiation non-absorbing substances, such as paper, plastic films and / or a color, adhesive and / or lacquer layer are preferably provided in the method as the basic components of the carrier, advantageously for tamper-proof marking or machine verification and simultaneous devaluation documents, labeled or marked.

In a particularly advantageous embodiment of the method, the starting materials stored in and / or on the carrier body are preferably introduced into the paper pulp as an additional additive in film production processes, such as calendering, extruding or film casting, or during papermaking and / or advantageously by coating methods, such as brushing, Spraying, spraying, coating, dipping, and / or by printing processes, such as offset, steel engraving, gravure printing, flexographic printing, screen printing, indirect high pressure, thermal transfer printing, electrophotography and ink-jet process brought into and / or on the carrier body.

With regard to the carrier body, the stated object is achieved by holding in and / or on it a number of starting materials such that laser-induced the reaction conditions for a synthesis reaction of the starting materials are adjustable.

The basic components of the carrier body are preferably the laser irradiation non-absorbing substances, such as paper, films, in particular thermoplastics, and / or a color, adhesive and / or lacquer layer.

The change in their absorption properties with respect to the wavelengths from the ultraviolet range over the visible range to the infrared range is expediently suitable for detecting the property or substance change of the starting materials caused by laser irradiation. For a particularly simple detection, the starting materials are advantageously chosen such that they are caused to undergo a synthesis reaction by changing their color visible to the human eye. For synthesis reactions under color reaction, inorganic substance mixtures are advantageously used as starting materials. These can be used in particular redox or complex formation reactions produce intense color information that is particularly resistant to light and moisture u.a. are thus also suitable for the marking of value and / or security documents with a particularly high degree of protection against counterfeiting. In particular, word and image characters, such as, for example, inscriptions, logos or barcodes, can be generated as colored information.

For one or more mono- or multicolor information selected as needed, the starting materials in the carrier body are preferably chosen such that the product of the respective synthesis reaction is assigned to each of a base color of a CMYK color scheme for cyan, magenta, yellow and contrast or black.

In order to use the carrier body particularly versatile, the carrier body is expediently equipped for the generation of permanent intense colored information. For a product with the assignment to the color blue ("cyan") MnSO ₄ , KNO ₃ and KOH are preferably provided as starting materials. Alternatively or cumulatively, for a product associated with the color red ("magenta"), preferably Fe ₂ (SO ₄ ) ₃ and KSCN are retained as starting materials. Alternatively or cumulatively to the colors blue ("cyan") and / or red ("magenta"), preferably Cr ₂ O ₃ , KNO ₃ and KOH are provided as starting materials for a product assigned to yellow ("yellow") ,

For an increase in the variety of colored information, in carrier for a product assigned to the color blue as starting materials, preferably Cu ²⁺ and NH ₃ for the reaction to the tetraammine copper complex or the substances Co (NO ₃ ) ₂ and Al ₂ O ₃ and / or for a product with the assignment to the color green as starting materials preferably Co (NO ₃ ) ₂ and ZnO or the substances K ₂ CrO ₄ and C ₃ H ₇ OH held.

To graphically allow very varied color patterns and variations in the carrier body, the starting materials of synthesis reactions of different color changes are preferably held in separate volume segments in the carrier body.

For generating differently colored information in a carrier body with a comparatively high color depth, in particular also with regard to a particularly reliable laser marking compared to counterfeiting and manipulation, in addition to the outer color design in this respect carrier body and an inner color design is appropriate. Therefore, the starting materials assigned to different color reactions are preferably kept in separate layers in the carrier body.

In order to focus the laser irradiation directly on at least one starting material, in particular if it alone is not or only insufficiently suitable for the absorption of the laser radiation, without destroying the carrier body with too high a laser energy, preferably the laser irradiation absorbing auxiliary substances or layers are in the carrier body embedded.

In a particularly advantageous embodiment of the carrier body is in it for the assignment to contrast or black alternatively or cumulatively to the colors blue ("cyan"), red ("magenta") and / or yellow ("yellow") as an adjuvant, the irradiated Laser radiation via interference or mirror effects transferred to a selected starting material, preferably a mica pigment, such as "Iriodin", but also simply titanium dioxide. or carbon in the form of carbon black, or advantageously also a colored pigment such as phthalocyanine.

In order to be able to use the carrier body reliably and flexibly in terms of time and place, the starting materials provided in it for a synthesis reaction are preferably at least partially enveloped by an encapsulation which inhibits this reaction until excitation by laser irradiation. In a particularly advantageous manner, the encapsulation is chosen such that it is broken up by the laser irradiation and releases the relevant starting material only when it breaks open as a reaction partner. For this, the encapsulation is preferably designed such that it absorbs the laser radiation itself.

For a reduction of the activation energy, in particular for redox reactions held in the carrier body starting materials, and in favor of the use of a comparatively low-power laser preferably catalytically active particles are embedded in the carrier body.

Use of the carrier body equipped in this way can expediently be found in all areas in which value and / or security documents are involved, in logistics or ticketing and for presentations. Therefore, the carrier body is preferably used as a passport, driver's license, credit or health card, ticket or foil.

The advantages achieved by the invention are, in particular, that constant information is generated precisely by the synthesis reaction of a number of starting materials. In particular, it is possible to use typical and sensitive detection reactions for secondary group metals which are known from the literature for the generation of particularly intensive colored information resistant to environmental influences. Just by irradiation of at least one reactant with laser light a reliable process control is possible. In this case, the laser irradiation ensures that a reaction temperature which is sufficiently high for the desired synthesis reaction is provided and / or that the irradiated substances are adequate strongly moved and / or caused to release reactive molecular species.

Furthermore, the support body allows by its particularly suitable equipment with encapsulations of particularly reactive starting materials, with the laser radiation absorbing excipients or layers and / or with catalytically active particles a specifically controlled process control. Thus, in the carrier body, if the starting materials of a synthesis reaction are already reactive at room temperature or by trituration with one another, at least one of the starting materials is encapsulated in the carrier body, so that the synthesis reaction is made possible only by laser-induced rupture of the encapsulation. While a laser material which does not or only slightly absorbs the starting material is indirectly activated by the laser radiation via auxiliary substances or layers embedded in the carrier body, the laser radiation is focused on the selected starting material via interference or mirror effects of the auxiliary substances or layers and there the local temperature increase produces a hot spot at which the starting material is brought into interaction with at least one further starting material or the monomolecular reaction. Catalytically active particles embedded in the support body lower the activation energy of the starting materials.

Furthermore, by embedding the starting materials of synthesis reactions of different color changes in separate volume segments and / or layers, the carrier body allows a high degree of flexibility with desired graphic designs in the form of diverse color variations and color patterns. The method for the laser-induced in-situ generation of information in the carrier body thus makes possible a use for marking or inscribing papers, films and other plastic documents, in particular increases the forgery-proofness of such a document and can furthermore be used for machine verification and simultaneous validation of documents. such as tickets, are used. Thus, the method can be used in all areas of daily life, in which it is about the rapid and locally targeted creation and / or incorporation of lasting word and / or image characters, among others.

An embodiment of the invention will be explained in more detail below.

In the following, various starting materials, their incorporation into and / or onto a carrier body and their laser initialization, which enables a wavelength-specific effect over the UV-VIS-IR range, are described.

Depending on the application, the starting materials selected for a desired synthesis reaction can be localized exactly by matrix or layer in an inner and / or outer region of a data carrier acting as a carrier by means of various introduction or application methods. As the carrier body underlying basic components or composite materials, for example, paper or plastic films, as well as between and / or applied to this color, adhesive or paint layers are used. In a preferred embodiment, the starting materials are introduced in the film production as an additional additive. This applies in particular to the usual film production processes, such as calendering, extrusion and film casting. In papermaking, the starting materials selected for the synthesis reaction can likewise be incorporated into the paper pulp as an additional additive. The incorporation into films and papers has the advantage that in the production of documents, such as cards and ID cards, in the production process itself, no significant interventions are necessary. By various coating methods, such as brushing, spraying, spraying, coating, dipping, and / or by printing processes, such as offset, steel engraving, gravure printing, flexographic printing, screen printing, indirect high pressure, thermal transfer printing, electrophotography and ink-jet processes can be for a desired synthesis reaction put selected starting materials in and / or on the carrier body.

In a preferred embodiment, a screen printing varnish highly filled with the starting materials is printed on an opaque plastic film and laminated with several layers of plastic film. This approach is a particularly flexible embodiment, as it allows for easy internal printing in the production of composite materials such as cards, cards made of solid plastic or paper-plastic compounds.

Of course, besides the complex formation and redox reactions mentioned in the exemplary embodiment of the starting materials held in the carrier body, other synthesis reactions are also conceivable, such as e.g. Eliminations in which a part of the molecule is split off, which also changes its physical properties, or additions in which new covalent bonds are linked and thus generate a "new" substance, or substitution reactions involving e.g. Ligands of a complex can be exchanged.

Example 1: Blue Laser Labeling

A stoichiometric mixture of the inorganic starting materials of cobalt (II) nitrate with aluminum sulfate and a binder is printed eg by screen printing on a plastic card. Optionally, the mixture still contains "Iriodin"(<0.5% by weight). This plastic card can then be laminated with a NIR-permeable overlay film. Upon irradiation with an Nd: YAG laser, the hot spot or hot spot produced thereby undergoes reaction to cobalt spinel CoAl ₂ O ₃ , known in the literature as Thenard's blue. The "Iriodin" serves in the extended formulation as the laser radiation absorbing excipient to transfer the laser radiation to the starting materials and thus focus on the starting materials and / or to minimize the laser energy required for the reaction. Excessive laser irradiation usually leads to carbonization, which can minimize or mask the blue color impression.

The reaction to thenards blue can be described by the following equation:

Co (NO ₃ ) ₂ + Al ₂ O ₃ → CoAl ₂ O ₃ + 2 NO ₂ + ½ O ₂

FIG. 1 schematically shows a pigment 2 "iriodin" embedded in a matrix 1 which absorbs the irradiated laser light 6 in its mica core 4 and, as is symbolized by a flash 8 in FIG. 1, has interference effects to those at its Interface 10 located in the matrix 1 inorganic starting materials Co (NO ₃ ) ₂ and Al ₂ O ₃ transferredriert. This results in a hot spot 12 at the interface 10 of the pigment 2, so that the reaction described in Example 1 is initiated with color change.

Example 2: Green laser marking

A stoichiometric mixture of the inorganic starting materials of 2 cobalt (II) nitrate with 1 zinc oxide is added in the embodiment in the film production, for example in the calendering process as an additive. Optionally, the mixture still contains proportions of "Iriodin"(<0.5 percent by weight). In the exemplary embodiment, this film is subsequently joined together with other components to form a plastic card which is covered only with an NIR-permeable overlay film. Upon irradiation with an Nd: YAG laser, the reaction generates the zinc-cobalt spinel ZnCo ₂ O ₄ , known in the literature as Rinmanns green, at the hot spot or hot spot produced thereby. The "Iriodin" serves in the extended formulation again as the laser radiation absorbing excipient, in order to focus the laser radiation on the starting materials and / or to minimize the laser energy required for the reaction. Excessive laser irradiation usually leads to carbonization, which can minimize or mask the green color impression.

The reaction to Rinmanns green can be described by the following equation:

2Co (NO ₃ ) ₂ + ZnO → ZnCo ₂ O ₄ + 4 NO ₂ + ½ O ₂

Example 3: Blue ("Cyane") Laser Marking

A stoichiometric mixture of the inorganic starting materials of pink manganese (II) sulfate with 2 potassium nitrate and 2 potassium hydroxide is added in the exemplary embodiment in the hotmelt film production as an additive to an adhesive. Optionally, the mixture still contains proportions of "Iriodin"(<0.5 percent by weight). In the exemplary embodiment, this film is subsequently joined together with other components to form a plastic card which is covered only with an NIR-permeable overlay film. Upon irradiation with a Nd: YAG laser, the reaction, which is also known as the oxidation melt, to the green-blue ("cyanene") manganate occurs at the hot spot or hot spot produced thereby. The "Iriodin" serves in the extended formulation in turn as the laser radiation absorbing excipient to focus the laser radiation to the starting materials and / or to minimize the laser energy required for the reaction. Excessive laser irradiation usually leads to carbonization, which can minimize or mask the green-blue ("cyan") color impression.

The reaction to green-blue ("cyanene") manganate can be described by the following equation:

MnSO ₄ + 2 KNO ₃ + 2 KOH → K ₂ MnO ₄ + 2 KNO ₂ + H ₂ SO ₄

Example 4 a) Yellow ("Yellow") Laser Labeling and b) Green Laser Labeling

• a) Eine stöchiometrische Mischung der anorganischen Ausgangsstoffe aus grünem Chrom(III)-oxid mit 3 Kaliumnitrat und 2 Kaliumhydroxid wird analog zu einem der Beispiele 1 bis 3 in eine Matrix eingebracht. Auf den Einsatz von "Iriodin" kann in diesem Ausführungsbeispiel verzichtet werden, da Cr³⁺ sehr gut im roten Spektralbereich absorbiert. Bei der Bestrahlung mit einem leistungsstarken Farbstoff- oder Halbleiter-Laser mit roter Emission (630 - 690 nm) tritt an dem dadurch erzeugten hot-spot oder der heißen Stelle die auch als Chrom-Oxidationsschmelze bekannte Reaktion zum gelb-orangen ("yellow") Dichromat (Cr ⁶⁺) ein.
  Die Redoxreaktion zum gelb-orangen ("yellow") Dichromat kann mit folgender Gleichung beschrieben werden:
  
          Cr₂O₃ + 3 KNO₃ + 2 KOH→ K₂Cr₂O₇ + 3 KNO₂ + H₂O
  
  
  b) Als Farbreaktion von gelb nach grün eignet sich die auch als "klassischer Alkoholtest" im Prüfröhrchen bekannte Reaktion vom gelben Kaliumchromat (Cr⁶⁺) mit Propanol, das in vielen Druckadditiven zumindest in Spuren vorhanden ist, zum grünen Chrom(III)-oxid nach der Gleichung:
  
          2 K₂CrO₄ + 3 C₃H₇OH → Cr₂O₃+ 3 C₃H₆O + 4 KOH + H₂O
  
  

Bei einer Implementierung in einem Trägerkörper ist die Mobilität des Systems beispielsweise durch Einlaminierung zu minimieren, um gesundheitliche Gefahren, die von den giftigen Chromaten ausgehen können, auszuschließen.

• a) A stoichiometric mixture of the inorganic starting materials of green chromium (III) oxide with 3 potassium nitrate and 2 potassium hydroxide is introduced analogously to one of Examples 1 to 3 in a matrix. The use of "iriodin" can be omitted in this embodiment, since Cr ³⁺ absorbs very well in the red spectral range. When irradiated with a powerful dye or semiconductor laser with red emission (630-690 nm) occurs at the resulting hot spot or the hot spot known as the chrome oxide melt reaction to yellow-orange ("yellow") Dichromate (Cr ⁶⁺ ).
  The redox reaction to the yellow-orange ("yellow") dichromate can be described by the following equation:
  
  Cr ₂ O ₃ + 3 KNO ₃ + 2 KOH → K ₂ Cr ₂ O ₇ + 3 KNO ₂ + H ₂ O
  
  
  b) As a color reaction from yellow to green, the well-known as "classic alcohol test" in the test tube reaction of yellow potassium chromate (Cr ⁶⁺ ) with propanol, which is present in many pressure additives at least in traces, to green chromium (III) oxide according to the equation:
  
  2 K ₂ CrO ₄ + 3 C ₃ H ₇ OH → Cr ₂ O ₃ + 3 C ₃ H ₆ O + 4 KOH + H ₂ O
  
  

In one implementation in a carrier body, the mobility of the system is to be minimized by, for example, lamination to eliminate health hazards that may emanate from the toxic chromates.

FIG. 2 schematically shows a pigment 2, yellow chromate (Cr ⁶⁺ ) embedded in a matrix 1, the matrix 1 containing as reducing agent 14 traces of an alcohol (R-OH). The flash 8 symbolizes a hot spot 12 induced by the irradiated laser light 6 or a hot spot at the boundary surface 10 of the pigment 2 (Cr ⁶⁺ ). to the matrix 1. There, the alcohol is oxidized to an aldehyde (R-HO) and the Cr ⁶⁺ reduced to the green Cr ³⁺ according to the equation described in Example 4b).

Example 5: Red (Magenta) Laser Labeling

• a) Iron in the oxidation state +3, eg iron (III) sulphate, forms a deep red ("magenta") complex with thiocyanates in the non-aqueous medium according to the equation:
  
  Fe ₂ (SO ₄ ) ₃ + 6 KSCN (+ 6H ₂ O) → 2 [Fe (SCN) ₃ (H ₂ O) ₃ ] + 3K ₂ SO ₄
  
  The complex formation takes place already during trituration of the starting materials with each other, so that the iron (III) sulfate encapsulated is introduced into the matrix and only the laser radiation breaks the encapsulation to stimulate the reaction with color change.
• b) Iron (II) sulphate requires no encapsulation. It is oxidized with potassium nitrate and potassium thiocyanate and water by the laser action to iron with the oxidation state +3, which immediately reacts to the deep red ("magenta"), characteristic complex according to the equation:
  
  2 FeSO ₄ + KNO ₃ + 6 KSCN + 4 H ₂ O → 2 [Fe (SCN) ₃ (H ₂ O) ₃ ] + KNO ₂ + 2 K ₂ SO ₄ + 2 KOH
  
  

Example 6: Red fluorescent laser lettering

Europium with the oxidation state +2 exhibits a local red fluorescence upon oxidation with saltpetre to the oxidation state +3 after laser irradiation in a blue fluorescent environment.
The redox reaction can be described by the following equation:

2 Eu ²⁺ + KNO ₃ + H ₂ O → 2 Eu ³⁺ + KNO ₂ + 2 OH ^-

Example 7: Multicolor Laser Labeling

Furthermore, the starting materials presented in Examples 3, 4 and 5 for their laser-induced characteristic color reactions can each be combined with one another in various mutually delimited layers 16a-d, which each represent a carrier body with a correspondingly reactive matrix, as shown in FIG , In the exemplary embodiment, a composite film structure with four different doped layers 16a-d are provided, wherein the bottom layer 16a with MnSO _4, KNO ₃ and KOH (Example 3), the second lowermost layer 16b with Fe ₂ (SO _{4) 3} and KSCN (Example 5), the third layer 16c from below with Cr ₂ O ₃ , KNO ₃ and KOH (Example 4) and the uppermost layer 16d is doped with "Iriodin". The respective synthesis reaction is initiated by irradiation with an Nd: YAG laser. The laser is focused, for example by a confocal optics, on selected volume segments 18a-d within the respective layer 16a-d (z coordinate) at specific positions (xy coordinates). Resolutions of about 10 μm in the xy direction and of about 30 μm in the z direction are achieved. Due to the comparatively low focusing sharpness in the z-direction, each layer 16a-d is individually scanned in order to carry out the synthesis reaction on the selected volume segments 18a-d. In this case, in the embodiment in the bottom layer 16a by the reaction of MnSO ₄ with KNO ₃ and KOH a color change to blue ("cyan") is achieved (Example 3). In the second step, the laser is then adjusted to the second lowest layer 16b and focused within it to the desired xy positions. Here, as a result of the irradiation by reaction of Fe ₂ (SO ₄ ) ₃ with KSCN, a color change to red ("magenta") is produced (Example 5). Analogously, the reaction of Cr ₂ O ₃ , KNO ₃ and KOH in the selected volume segments 18 c is induced in the third layer 16 c from below and thus the color change to yellow ("yellow") is achieved (Example 4). Finally, in the exemplary embodiment, the spatially resolved irradiation is carried out in the top layer 16d doped with "iriodin". In this case, a gray to black color change is produced in the selected volume segments 18d by the local overheating, which represents the contrast. If the film composite structure after the laser-induced inscription process is viewed perpendicular to the layers 16a-d, the overlaying of the individual colored volume segments 18a-d results in a full-color CMYK image by subtractive color mixing. The above spatial resolutions enable images with a resolution of more than 600 dpi, which is the standard resolution of modern color printers.

LIST OF REFERENCE NUMBERS

1

matrix

2

pigment

4

mica core

6

irradiated laser light

8th

lightning

10

interface

12

hot-spot

14

reducing agent

16a-d

layer

18a-d

volume segments

Claims (29)

1. Process for generating coloured information in a carrier body of a value and/or security document, in which a plurality of inorganic starting materials are provided with the carrier body, in which paper, plastic films and/or a coloured, adhesive and/or lacquer layer are provided as basic components, characterised in that the starting materials are provided in the form of a stoichiometric mixture of the starting materials in a localised part region of the carrier body and that thermal energy, which provides an activation energy of a synthetic colour reaction and which lead to activation of at least one starting material with at least one further starting material, is introduced by laser irradiation in the part region under local temperature increase, and these starting materials are caused to give the synthetic colour reaction with one another in the form of a redox reaction or a complex-forming reaction in the part region with formation of a colour-changed product, as a result of which coloured information is produced.
2. Process according to claim 1, characterised in that coloured information with respect to wavelengths in the ultraviolet to infrared range is produced by the colour reaction with formation of the product.
3. Process according to claim 1 or 2, characterised in that coloured information is produced while changing a colour of the starting materials, which is visible to the human eye, by forming the product.
4. Process according to one of claims 1 to 3, in which the mixture is a matrix which can be reacted to give the colour reaction.
5. Process according to one of claims 1 to 4, in which a material change of the starting materials without activation energy is avoided.
6. Process according to one of claims 1 to 5, in which the starting materials are inert with respect to the carrier body.
7. Process according to one of the preceding claims, in which the starting materials are selected such that the product of the particular colour reaction is assigned in each case to a primary colour of a CMYK colour scheme.
8. Process according to one of the preceding claims, in which starting materials to give colour reactions of different colour changes are provided in the carrier body in volume segments (18a-d) which are delimited from one another.
9. Process according to one of the preceding claims, in which starting materials to give colour reactions of different colour changes are provided in the carrier body in layers (16a-d) which are delimited from one another.
10. Process according to one of the preceding claims, in which at least one of the starting materials is provided encapsulated, wherein the encapsulation is selected such that it is broken up by the laser irradiation.
11. Process according to one of the preceding claims, in which the laser irradiation-absorbing auxiliaries or layers are embedded in the carrier body.
12. Process according to one of the preceding claims, in which particles acting catalytically for the colour reaction are embedded in the carrier body.
13. Process according to one of the preceding claims, in which a laser having emissions from the UV to IR range is used for laser irradiation.
14. Process according to one of the preceding claims, in which an Nd:YAG laser having an emission wavelength of 1,064 nm is used for laser irradiation.
15. Process according to one of the preceding claims, in which materials which do not absorb laser irradiation are provided as basic components of the carrier body and are written on or marked for forgery-safe identification or for machine verification and simultaneous devaluation of documents.
16. Process according to one of the preceding claims, in which the starting materials provided in and/or on the carrier body are introduced into the carrier body as an additional additive during film or paper production and/or applied to the carrier body by coating processes, such as brushing, spraying, sprinkling, coating, immersion, and/or by printing processes, such as offset, steel-engraving printing, half-tone intaglio printing, flexographic printing, screen printing, indirect relief printing, thermo-transfer printing, electrophotography and ink-jet processes.
17. Value and/or security document with a carrier body, in which a plurality of inorganic starting materials are provided with the carrier body, in which paper, plastic films and/or a coloured, adhesive and/or lacquer layer are provided as basic components, characterised in that the starting materials are provided in the form of a stoichiometric mixture of the starting materials in a localised part region of the carrier body such that, that thermal energy, which provides an activation energy of a synthetic colour reaction and which leads to activation of at least one starting material with at least one further starting material, can be introduced by laser irradiation in the part region under local temperature increase, and these starting materials give rise to a colour reaction in the form of a redox reaction or a complex-forming reaction in the part region with formation of a colour-changed product, as a result of which coloured information is produced in the carrier body.
18. Value and/or security document according to claim 17, in which the starting materials are selected such that the product of the particular colour reaction is assigned in each case to a primary colour of a CMYK colour scheme.
19. Value and/or security document according to claim 17 or 18, in which for a product with assignment to the colour blue ("cyan"), MnSO₄, KNO₃ and KOH are provided as starting materials.
20. Value and/or security document according to one of claims 17 to 19, in which for a product with assignment to the colour red ("magenta"), Fe₂(SO₄)₃ and KSCN are provided as starting materials.
21. Value and/or security document according to one of claims 17 to 20, in which for a product with assignment to the colour yellow ("yellow"), Cr₂O₃, KNO₃ and KOH are provided as starting materials.
22. Value and/or security document according to one of claims 17 to 21, in which for a product with assignment to the colour blue, Cu²⁺ and NH₃ or the substances Co(NO₃)₂ and Al₂O₃ are provided as starting materials and/or for a product with assignment to the colour green, Co(NO₃)₂ and ZnO or the substances K₂CrO₄ and C₃H₇OH are provided as starting materials.
23. Value and/or security document according to one of claims 17 to 22, in which starting materials to give colour reactions of different colour changes are provided in the carrier body in volume segments (18a-d) which are delimited from one another.
24. Value and/or security document according to one of claims 17 to 23, in which starting materials to give colour reactions of different colour changes are provided in the carrier body in layers (16a-d) which are delimited from one another.
25. Value and/or security document according to one of claims 17 to 24, in which the laser irradiation-absorbing auxiliaries or layers are embedded.
26. Value and/or security document according to one of claims 17 to 25, in which for assignment to contrast or black, a mica or coloured pigment is provided as an auxiliary which absorbs the laser irradiation.
27. Value and/or security document according to one of claims 17 to 26, in which at least one of the starting materials of a colour reaction is provided encapsulated, wherein the encapsulation is selected such that it is broken open by the laser irradiation.
28. Value and/or security document according to one of claims 17 to 27, in which particles acting catalytically for the colour reaction are embedded.
29. Use of a value and/or security document according to one of claims 17 to 28 as an identity card, driving licence, credit card or medical card, or as a ticket or film.

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