DE102024114735A1 - DOCUMENT BODY WITH A MARKING FORMED IN A LAMINATE AND METHOD AND DEVICE FOR ITS MANUFACTURING - Google Patents

Abstract

Method and apparatus for producing a document body comprising a multilayer laminate and generating a multicolored, data-representing marking within the laminate. The method comprises:
- Providing or creating an initial marking in or on an extensive substrate. The initial marking has several colored sub-areas, each forming only a part of the initial marking, such that the colors of at least two of the sub-areas differ from each other.
- Creating the laminate by laminating the base substrate as the first laminate layer with at least one further, planar-extended substrate as each subsequent laminate layer, such that the initial marking is at least partially located inside the produced laminate;
- Causing an energy input into the laminate such that it acts locally selectively in the initial marking, whereby the multicolored marking representing the data is achieved at least partially from the initial marking by means of the locally selective color change of the initial marking (1) caused by the energy input into the initial marking.

Description

The present invention relates to a document body, in particular for an individualized document, comprising a multilayer laminate with data inscribed therein, wherein a multicolored marking is formed inside the laminate, representing the inscribed data. The invention further relates to a method and a device for manufacturing such a document body.

A wide variety of individualized, and especially personalized, documents, such as those in card or book form, are known from the current state of the art. For example, book-like passport documents or individual pages thereof (e.g., the so-called "passport holder's page" or paper pages), identity cards, and many types of personalized chip cards, such as bank cards, credit cards, ID cards, membership cards, access cards, etc., or personal (mostly card-shaped) labels, all belong to the group of often individualized documents. In particular, such individualized, especially personalized, documents that are also security-relevant ("security documents"), such as passports or identity cards (e.g., national identity cards or access identification cards), must generally meet several criteria. They must, for example, regularly exhibit high resistance to potential environmental influences and a long service life, e.g., in the case of passport documents, typically up to 10 years.

Furthermore, the presence of one or often several security mechanisms to protect against forgery is frequently required. Such security mechanisms can be achieved, in particular, through the use of special materials and their targeted arrangement within the document and/or special manufacturing or processing methods (e.g., offset printing). Last but not least, the document must usually also be aesthetically pleasing, as government-issued identity documents are often seen as a calling card for the respective country and are intended to reflect not only the individual's identity but also that of the country itself.

A document of the aforementioned type (e.g., an identity card), or a document body thereof (such as a so-called data page of a passport, which may also include, for example, further pages and a cover), is in many cases composed of several layers, especially films (usually made of polycarbonate), between which, particularly in the case of a security document, individual security features (such as holograms or offset printing) may be located as protective mechanisms. During the production of the document, the individual layers are placed on top of each other and bond together under pressure and temperature during a lamination process to form a so-called document body, which is sometimes also referred to in technical terms as a "monoblock".

A security feature on the outside of a document is more easily accessible and therefore generally easier to tamper with than one located inside the document, which is more difficult to access. Internal security features are better protected against direct influences – such as liquid chemicals or extraction from the document – and thus contribute to greater document security.

This basic principle is also usually applied to the personalization or individualization of security documents, in particular to provide a security document with personal data, such as a passport photo or biometric information about the document holder to whom the security document is or will be issued.

The transmission of security-relevant data, especially personal data, is highly sensitive from both a security and data protection perspective. Therefore, the production of security documents is generally a multi-phase process. The first phase involves the production of the blank, consecutively numbered document body by a document supplier, followed by a subsequent phase in which the document is personalized in a protected environment, usually under the supervision of government authorities in the case of government security documents.

Such personalization is often carried out using a grayscale laser, e.g., with a wavelength of 1064 nm (the so-called standard wavelength) or a wavelength of 355 nm (UV laser), or another wavelength suitable for the material being processed and the desired resolution. For this process, one or more layers of the security document are laser-reactive and turn black under the influence of the laser radiation. Personal data such as name, date of birth, or image are then added. They thus become part of the monoblock and are therefore better protected against forgery attempts and environmental influences. However, a data representation generated in this way, e.g., an image or text, is binary (e.g., black and white or black and transparent) or only exhibits several shades of gray. It is not a color representation of the data, i.e., not a representation with multiple colors, including at least one color other than black, white, and shades of gray.

A well-known technique for creating color images in security documents involves printing a color image onto a film and inserting this film—as an insert—into the multi-layered security document or the document body before the lamination process. This means that customer-specific personalization is only possible before the document is produced. The process is therefore complex and feasible in only a few projects.

It is an object of the invention to provide an improved document body (monoblock) as well as a method and a device for its manufacture in such a way that a multicolored marking is formed or is formed inside the document body, which represents data inscribed therein.

To solve this problem, the respective devices or methods are proposed according to the teachings of the independent claims. Various embodiments and further developments of the solution are the subject of the dependent claims.

1. (a) Bereitstellen oder Herstellen einer Ausgangsmarkierung in oder auf einem flächenhaft ausgedehnten, insbesondere platten- oder folienartigen, Grundsubstrat, wobei die Ausgangsmarkierung mehrere farbige (insbesondere jeweils einfarbige) Teilbereiche, (d. h. Flächen- oder Raumbereiche, die jeweils nur einen Teil der Ausgangsmarkierung bilden) derart aufweist, dass sich die Farben von zumindest zwei der Teilbereiche voneinander unterscheiden.
2. (b) Erzeugen des Laminats durch Lamination des Grundsubstrats als erste Laminatschicht mit zumindest einem weiteren flächenhaft ausgedehnten, insbesondere platten- oder folienartigen, Substrat als jeweils weitere Laminatschicht derart, dass die Ausgangsmarkierung zumindest anteilig im Inneren des erzeugten Laminats, d. h. von der äußeren Oberfläche des Laminats allseitig umschlossen, zu liegen kommt;
3. (c) Bewirken eines Energieeintrags in das Laminat derart, dass er in der Ausgangsmarkierung örtlich-selektiv (d. h. selektiv nur in einem oder mehreren Flächen-. oder Volumenabschnitten der Ausgangsmarkierung, in zumindest einem anderen Flächen- oder Volumenabschnitten dagegen nicht) wirkt, wodurch die Daten repräsentierende mehrfarbige Markierung zumindest anteilig aus der Ausgangsmarkierung anhand einer durch den Energieeintrag in die Ausgangsmarkierung bewirkten, örtlich-selektiven farblichen Veränderung der Ausgangsmarkierung erreicht wird.

A first aspect of the solution presented here concerns a method for producing a document body with a multi-layered laminate, generating a multi-colored marking within the laminate that represents data (in particular, personalization, such as text or image). The method features:

1. (a) Providing or producing an initial marking in or on a planar, in particular plate- or film-like, base substrate, wherein the initial marking has several colored (in particular each monochromatic) sub-areas (i.e. area or spatial regions, each forming only a part of the initial marking) such that the colors of at least two of the sub-areas differ from each other.
2. (b) Producing the laminate by laminating the base substrate as the first laminate layer with at least one further planar extended substrate, in particular plate- or film-like, as each further laminate layer such that the initial marking is located at least partially inside the produced laminate, i.e. enclosed on all sides by the outer surface of the laminate;
3. (c) Causing an energy input into the laminate such that it acts locally selectively in the initial marking (i.e. selectively only in one or more surface or volume sections of the initial marking, but not in at least one other surface or volume section), whereby the multicolored marking representing the data is achieved at least partially from the initial marking by means of a locally selective color change of the initial marking caused by the energy input into the initial marking.

The term "color" and variations thereof (e.g., "colored"), as used herein, refers to any color other than black, white, and shades of gray obtained solely from mixing black and white. In particular, the color may be a color from a predefined color space, such as one of the well-known RGB (red/green/blue) or CMYK (cyan/yellow/magenta) color spaces.

The term "multicolored", as used herein, with regard to a multicolored object, in particular a mark in the document body, is to be understood as containing at least two colors or at least one color (each as defined above) and additionally, white, black or at least one shade of gray.

The term "energy input," as used herein, refers to any form of energy being introduced into the document body that produces the aforementioned effect in the initial marking. The energy input may, in particular, comprise various components that differ in their nature (e.g., radiation, pressure, temperature, charge), duration of action, depth of effect in the laminate, intensity, and/or, specifically in the case of radiation, in their wavelength or wavelength spectrum. Thus, it is also possible that only one component or a subset of the components causes the aforementioned color change in the initial marking, especially if applicable. A switching of the leuco dyes causes, while one or more other components of the energy input, depending on the embodiment of the process, additionally cause another change in the document body (e.g., blistering or carbonization, as described below).

Any terms used herein, such as "comprises," "includes," "includes," "features," "has," "with," or any other variant thereof, are intended to cover non-exclusive inclusion. For example, a method or apparatus that includes or features a list of elements is not necessarily limited to those elements but may include other elements not expressly listed or inherent in such method or apparatus.

Furthermore, unless explicitly stated otherwise, "or" refers to an inclusive "or" and not an exclusive "or". For example, a condition A or B is satisfied by one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).

The terms "ein" or "eine," as used here, are defined as "one or more." The terms "ein anderer" and "ein Weitere," as well as any other variant thereof, are to be understood as "at least one more."

The term "plural", as it may be used here, is to be understood in the sense of "two or more".

The terms “first”, “second”, “third”, and similar terms in the description and in the claims are used to distinguish between similar or otherwise identically named elements and not necessarily to describe a sequential, spatial, or chronological order. It is understood that the terms used in this way are interchangeable under suitable circumstances and that the embodiments of the solution described herein may also function in orders other than those described or illustrated here.

The terms "configured" or "set up" to perform a specific function (and their respective variations), as used here, mean that a device or component thereof already exists in a configuration or setting capable of performing the function, or at least is adjustable—i.e., configurable—so that it can perform the function after appropriate adjustment. Configuration can be achieved, for example, by adjusting process parameters or by using switches or similar devices to activate or deactivate functionalities or settings. In particular, the device may have several predefined configurations or operating modes, allowing configuration by selecting one of these.

The proposed method allows for the creation of a document body, particularly for security-relevant documents, in which a colored marking is embedded within it, thus protecting it from direct access. Furthermore, the creation of the initial marking and the generation of the colored marking through energy input can be separated entirely or partially in time, enabling the document to be personalized at a later time and location than the production of the laminate (monoblock) including the embedded initial marking. Moreover, the achievable security standard can be increased because the ability to generate a wide variety of colors (i.e., a large color gamut) with high resolution within the colored marking drastically expands the range of personalization options compared to previous black-and-white or grayscale images.

The following section describes various exemplary optional embodiments of the solution-based method, which, unless expressly excluded or technically impossible, can be combined with each other and with the other aspects of the present solution described below.

The energy input can be achieved, at least partially, by means of a locally selective application of electromagnetic radiation to the initial marking located within the laminate using a sub-surface laser processing method. In this process, laser radiation emitted through the surface of the document body selectively degrades the dye present in the initial marking. Material is processed or removed. For this purpose, the properties of the laser radiation can be specifically adapted. Such adaptation can relate in particular to the radiation intensity, the wavelength used, the irradiation duration, the beam diameter, and/or the irradiation angle. This method of material processing and/or material removal inside a body using external laser irradiation is often referred to in technical terminology as sub-surface laser processing (SSLE).

The use of laser radiation for creating colored markings allows for a particularly high spatial resolution of the colored marking (target marking), since the laser beam can be applied with a very small cross-section, thus generating very small pixels in the colored marking. Furthermore, it allows for high processing speeds, which is especially relevant for the mass personalization of documents.

For the execution of the subsurface laser processing method, an ultrashort pulse laser can be used, in particular, to effect the locally selective energy input into the initial marking. Such lasers typically have pulse durations in the picosecond or femtosecond range. The pulse width can also be very small, for example, only 0.3 µm. Depending on the intensity and pulse duration, the ultrashort light input can vaporize the material at specific points, leading to highly precise structures, or, in the case of the leuco dyes mentioned below, causing their local switching at an energy input below the vaporization threshold. Furthermore, in both cases, the temperature load in the immediate vicinity is minimized. This enables the processing of very thin (e.g., thicknesses in the range of one or a few micrometers) or heat-sensitive materials or material layers, and even transparent materials can often absorb such light pulses if the radiation intensity is sufficient.

Furthermore, within the framework of this process, the focal length of a laser used to perform the sub-surface laser processing can be adjusted depending on the location of the initial marking or, in the case of layered construction, on the location of a selected sub-layer of the initial marking, such that a focal point corresponding to the focal length lies on or within the initial marking or its selected sub-layer. This allows the initial marking to be processed with pinpoint accuracy to produce the colored marking, by maximizing the radiation energy density precisely at the point of desired effect, without significantly affecting other areas of the document (where correspondingly lower radiation energy densities occur).

• - einem farbigen und einem andersfarbigen Zustand oder
• - einem opaken und einem zumindest teiltransparenten Zustand oder
• - jeweils umgekehrt,

umschaltbar ist. Die farbliche Veränderung der Ausgangsmarkierung wird sodann zumindest anteilig anhand eines durch den Energieeintrag in die Ausgangsmarkierung bewirkten, örtlich-selektiven Umschaltens des Leuko-Farbstoffs erzeugt.The locally selective color change of the initial marking caused by the energy input can be produced, in particular, wholly or partially, by at least one of the colors being caused at least partially by colorants that are or become leuco-dyes, which are activated by the energy input at the point of its action on the leuco-dye.

• - a colored state and a differently colored state or
• - an opaque and at least partially transparent state or
• - each in reverse,

The color change of the initial marking is then generated, at least partially, by means of a locally selective switching of the leuco dye caused by the energy input into the initial marking.

• - Halochrome Leuko-Farbstoffe: Anregung durch eine elektrische Ladungsänderung;
• - Photochrome Leuko-Farbstoffe: Anregung durch elektromagnetische Bestrahlung, insbesondere Licht;
• - Piezochrome Leuko-Farbstoffe: Anregung durch Druckänderung;
• - Thermochrome Leuko-Farbstoffe: Anregung durch Temperaturänderung.

The term "leuco dye," as used herein, refers to a dye that, through the input of energy and a resulting change in its chemical structure, can be switched between (i) a colored and a differently colored state, or (ii) an opaque and at least partially transparent, particularly colorless, state, or (iii) vice versa. Leuco dyes are thus chemical compounds (such as nitrogen compounds) that possess the ability to change their color by altering their state. This occurs, however, only through external excitation, meaning that an input of energy into the compound is required to trigger the color change. Since the color change is achieved in different ways, leuco dyes can be classified according to the nature of their external excitation by energy input, in particular according to the following classification:

• - Halochrome leuco dyes: Excitation by a change in electrical charge;
• - Photochromic leuco dyes: Excitation by electromagnetic irradiation, especially light;
• - Piezochromic leuco dyes: Excitation by pressure change;
• - Thermochromic leuco dyes: Excitation by temperature change.

In the following, without this being understood as a limitation of the present solution, photochromic leuco dyes in particular are used as examples, since particularly fine and closely localized switching effects can be achieved in surfaces or volumes coated with leuco dyes by local irradiation, especially using laser light.

The process can further include performing a distortion correction with respect to a locally selective first energy input pattern, in particular an irradiation pattern, intended as the target pattern for energy input, before or during the application of the energy, according to a second energy input pattern resulting from the distortion correction. In this process, the second energy input pattern is derived from the first energy input pattern based on correction information determined by a detected deviation of the actual shape of the produced laminate from a target shape defined for the laminate. The correction information can, in particular, identify such a deviation. The aforementioned distortion correction can be used, in particular, to improve the reproduction quality of the target pattern in the colored marking to be produced and thus for quality assurance.

Furthermore, the initial marking can be provided or produced, at least in sections, as a raster graphic consisting of pixels or line segments, wherein the raster graphic has at least two different colors, in particular color channels of a specific multidimensional color space. The use of such a raster graphic for the initial marking enables, in particular, a spatially homogeneous color supply within the initial marking and simplified control of the energy input required to produce the colored marking. Moreover, this also allows the potentially colorless areas of the initial marking to be easily defined with a high degree of spatial homogeneity, which is advantageous with regard to uniform and thus reliable adhesion within the laminate. Various conceivable variants of raster graphics suitable for this purpose are explained in the figure description.

The initial marking can be provided or produced, in particular, as a raster graphic with at least three colors, using pixels as image points. Each pixel contains at least a subset of all colors present in the raster graphic from the set of colorants, and optionally, a subpixel not colored by any of the colorants. The latter can be advantageous in two respects: Firstly, it can serve as an additional color channel, for example, if this subpixel not colored by the colorants inherently possesses a color, such as white or black, that is not within the color space defined by the colorants of the raster graphic itself. Secondly, such a subpixel can also be advantageous with regard to the improved adhesion between the base substrate supporting the raster graphic and an adjacent substrate in the laminate, as mentioned previously. Accordingly, in the case of a raster graphic with several groups of line segments, in which the line segments of each group are adjacent and of different colors, at least one of the groups can each contain line segments of all colors occurring in the raster graphic from the set of colorants and optionally a line not colored by any of the colorants.

Within the framework of raster graphics (pixels and/or line segments), pixel or line variation can also be used to define the tonal value (i.e., brightness) for at least one of the colors of the raster graphic. This is achieved by using such a method that, when creating the multicolored marker, the color change of the initial marker is applied proportionally to the area of each pixel or line segment, depending on the tonal value to be represented. This can be done, for example, by selectively editing the initial marker, in particular by switching a leuco dye (if present) and/or by selectively removing color for that specific color. In this way, a very fine-grained brightness definition can be achieved for the colored marker, especially with a resolution even higher than that defined by the arrangement of the pixels. This also allows for the diverse range of applications possible using colored markers. to further increase the colors or shades that can be displayed to the viewer, and thus in particular also increase the achievable level of security of the document.

The initial marking can also be designed to contain at least one polymer material, in particular polycarbonate (e.g., opaque, transparent, or a partial combination of both), which is carbonizable by radiation. The locally selective energy input into the initial marking involves locally selective irradiation, in particular laser irradiation, of the initial marking, by means of which locally selective carbonization of the polymer material in the initial marking is effected. This can be used, in particular, to generate maximally dark, especially black, image components of the multicolored marking. For example, a color space defined for the colored marking can be extended by an additional color channel, in particular a CMY color space to a CMY(K) color space, where "K" stands for "key" (black component). Carbonization can be used, in particular, to generate character or text components in the colored marking.

The term “carbonization”, as used herein, refers in particular to at least partial local carbonization, i.e. an increase in the local content of elemental carbon in the material at the site of irradiation.

Irradiation can be carried out with variable irradiation intensity and/or duration, allowing the degree of carbonization at each point of impact within the polymer material to be varied with respect to the proportions of the colored marking formed by the irradiation, thus defining tonal values, particularly grayscale values. This makes it possible to set different tonal values even within the areas of the colored marking to be discolored by carbonization, thereby further increasing the range of possible marking variations and the achievable image quality.

To produce the initial marking, the colorants can be applied, at least partially, to the base substrate by printing on it and/or applying one or more additional substrates, each containing a corresponding colorant, in particular a film or plate containing or carrying the colorants, as a respective partial layer of the initial marking.

The base substrate can contain a polymer material as a component or be entirely composed of it. To produce the initial marking, at least one of the colorants can be a polymerizing colorant selected to form a polymer bond with the base substrate during lamination. This allows for particularly strong and durable adhesion of the colorants to the base substrate. Furthermore, good adhesion between the colorants and any additional substrate in contact with them can be optimized if the colorants are positioned between the base substrate and the additional substrate during lamination, thus forming a polymer bond on both sides. The polymer material can be opaque or transparent (e.g., polycarbonate, PC).

The initial marking can be defined in such a way that the area or space occupied by the colorants after the initial marking has been created constitutes at least 51%, in particular at least 71%, and especially at least 91% of the area or space enclosed by the surface of the initial marking. These value ranges allow for a particularly favorable design with excellent adhesion.

The initial marking can be produced, at least in part, as a prefabricated stack of layers consisting of several differently colored, each opaque or semi-transparent (especially in the visible range of the electromagnetic spectrum), one or more of which may contain one or more colored areas containing leuco dye. It is also possible for one of these layers to be uncolored (i.e., white, black, or gray). The layers of the stack can optionally be bonded together before lamination (e.g., by stapling, clamping, pre-lamination, or gluing) or simply stacked on top of each other. The multicolored marking can thus be achieved by selectively switching the leuco dye and/or selectively removing one or more layers to expose an underlying layer of a different color.

The prefabricated layer stack can be selected with regard to its format and positioned relative to the base substrate before joint lamination such that a projection of the layer stack onto a virtual plane orthogonal to its stacking direction lies completely within a projection of the base substrate onto the same virtual plane. It can therefore be smaller than the base substrate with respect to its lateral extent.

Specifically, the prefabricated layer stack can be at least partially integrated into a cavity formed in the base substrate. The cavity can be formed, in particular, in an opaque base substrate or a section thereof, so that together with the layer stack, an opaque layer with an embedded color marking area is created. This integration saves space. Especially if the cavity does not penetrate the base substrate but has a bottom within it, the layer stack embedded in the cavity can be covered and thus protected on only one side with another substrate, allowing the document body to be made thinner overall. The cavity can be created, for example, using specially shaped laminating tools, particularly laminating sheets with a raised structure or an outwardly convex or bulged shape in the cavity area, during the production or lamination of the base substrate layers. This step can be performed, in particular, in a process preceding the actual lamination of the layer stack with the base substrate. During the lamination of the layer stack located in the cavity of the base substrate with another substrate to form a common laminate, the cavity can be completely filled and enclosed, particularly with a substrate that is heated during the lamination process and thus partially melted or becomes flowable. This allows the embedding to be made even stronger or more secure.

It is also possible to apply a metal layer to a surface of the laminate—which, as the surface of a laminate layer, can be located partially or completely within the laminate structure—before generating the multicolored marking, and to create one or more selectively localized openings in the metal layer. Through at least one of these openings, selective energy can then be introduced into the laminate at the location of the initial marking. This process generates the multicolored marking representing the data from the initial marking by selectively processing or removing dye, and in particular, optionally, by switching a leuco dye. The metal layer selectively covers the underlying dye. By choosing the locations of the openings, the switching of the leuco dye can thus be precisely controlled at the points desired for image generation. If the colorants are distributed under the metal layer in such a way that, as in the raster graphic mentioned above, different color areas are found at different locations, then the desired color can be selectively achieved by choosing the locations of the openings. This is done by selectively exposing the desired colors at each location while concealing unwanted colors. Consider, in particular, pixels with different colored subpixels, so that at a given location of a pixel, for example, only one subpixel is selectively exposed (if only the color of the associated color channel is desired), or two or more subpixels are exposed, possibly only partially, to represent a mixed color depending on the respective exposed proportions. Instead of, or in a locally selective combination with, the aforementioned raster graphic, a line graphic can also be used as the initial marker, in which different colored lines are arranged next to each other, especially parallel to each other. Different colored pixels can then be represented by having a pixel extend section by section over several, in particular three, of the adjacent lines and locally-selectively at the location of this respective pixel, according to the desired color, one or more of the sections of the lines belonging to the pixel are exposed, while sections with unwanted colors remain covered or are only partially exposed to achieve a desired mixed color.

It is also possible for the document body to be designed in such a way that it has, at one or more points, a partially transparent window area (clear window) enclosed by an opaque area, which is at least partially covered by the metal layer or at least partially contains the metal layer. By selectively creating openings in the metal layer, a pattern visible through the metal layer can thus be formed as an additional security feature.

In particular, it is also possible to position the initial marking, at least partially, within the window area so that it is covered by the metal layer. By selectively creating openings in the metal layer, this layer can be used, as previously explained, to selectively expose colorants within the initial marking to create the colored marking, thus making them visible in transmitted light and/or to arrange them through the openings within the initial marking. to selectively process or remove dyes, in particular to selectively switch any leuco dyes that may be present.

In another way of defining the colored marking, at least one of the additional substrates in the laminate contains a polymer material, particularly a transparent or semi-transparent one, such as polycarbonate, in which local bubble formation can be induced by a locally selective energy input. This energy input is effected, particularly in photonic form, such that it causes local bubble formation in the polymer material of the at least one additional substrate. This leads to a color change, particularly bleaching or a reduction in transparency, of the polymer material at the point of energy input, thereby forming an opaque or semi-transparent locally selective mask of the original marking, which contributes at least partially to defining the multicolored marking.

Furthermore, one of the additional substrates can be designed as an optically variable layer whose color and/or transparency (especially in the visible range of the electromagnetic spectrum) can be locally modified, particularly bleached, by spatially selective energy input at the point of impact. This locally selective energy input is achieved by causing a local change in the color and/or transparency of the optically variable layer at the respective point of impact, thereby forming a locally selective mask of the initial marking, particularly opaque or semi-transparent, which contributes at least partially to defining the multicolored marking. The energy input can again be achieved in photonic and/or thermal form, particularly by means of laser radiation.

In further process variations, (at least) one of the additional substrates, which can coincide with the optically variable layer, can be designed as a metal layer that at least partially covers the initial marking. Through locally selective energy input, the metal is then locally removed from the metal layer, thereby selectively exposing a visible area of the initial marking, which contributes at least partially to defining the multicolored marking. The metal layer can be, for example, a film or formed by deposition, e.g., using chemical vapor deposition (CVD). Another possible manufacturing method is based on hot stamping. The process is similar to that used for processing a hologram. A very thin layer of metal applied to a carrier material is transferred, using a preheated stamping tool and under high pressure, to the aforementioned additional substrate, which serves as a document layer and can consist, at least partially, of transparent polycarbonate.

Previously, a number of different methods for producing the colored marking from the initial marking were described. They all have in common that they are used to partially or completely define the colored marking and that, both individually and especially in the diverse combinations of two or more of these methods, they can create multicolored security features for the document body that are particularly difficult to forge.

A second aspect of the present solution concerns a document body, particularly for a security-relevant document. The document body comprises a multi-layered laminate with data inscribed therein. A multi-colored marking, representing the inscribed data, is formed within the laminate. The document body is obtainable by carrying out the method according to the first aspect, particularly according to one or more of its embodiments described herein.

A third aspect of the present solution concerns a device for producing a document body comprising a multi-layered laminate and generating a multi-colored, data-representing marking inside the laminate. The device comprises:

• (i) a marking device for providing or producing an initial marking on a planar, in particular plate- or film-like, substrate using colorants, such that the initial marking has several colored sub-areas in such a way that the colors of at least two of the sub-areas differ from each other;
• (ii) a laminating device for producing a laminate from the base substrate and at least one further planar substrate;
• (iii) an energy source for effecting a locally selective energy input into the laminate at the location of the initial marking during or after the manufacture of the laminate; and
• (iv) a control device configured to cause the device to perform the method according to the first aspect, in particular according to one or more of its embodiments described herein, for the production of the document body with data inscribed therein.

In some embodiments of the device, the marking device is configured to provide or produce the initial marking on the base substrate using the colorants, each of which is or is designed as a leuco-dye, wherein the respective leuco-dye can be switched between a colored and a differently colored or an opaque and an at least partially transparent state, or vice versa, by an energy input at the point of its action on the leuco-dye.

The features and advantages explained in relation to the first aspect of the solution also apply accordingly to the other aspects of the solution.

Further advantages, features and application possibilities of the present solution will become apparent from the following detailed description in the context of the figures.

• 1 schematisch verschiedene beispielhafte Ausführungsformen (Varianten) einer jeweils als Rastergrafik ausgeführten Ausgangsmarkierung auf einem Grundsubstrat;
• 2 gemäß beispielhafter Ausführungsformen, jeweils schematisch (a) ein aus mehreren, jeweils ein Subpixel bildenden, Rasterpunkten (Dots) der Rastergrafik aus 1(a), aufgebautes Pixel, (b) ein aus mehreren, jeweils ein Subpixel bildenden, Liniensegmenten aufgebautes Pixel, (c) eine aus Liniensegmenten mit den Farben CMY aufgebaute Rastergrafik, und (d) eine aus Liniensegmenten mit den Farben CMYW aufgebaute Rastergrafik;
• 3 und 4 gemäß beispielhafter Ausführungsformen zur Illustration verschiedener Farbsättigungen einen beispielhaften Vergleich zweier verschiedener Rastergrafiken, sowohl in makroskopischer Ansicht (3) als auch in mikroskopischer Ansicht (4) und jeweils unter Verwendung der Grundfarben C, M und Y, jedoch mit verschiedenen Anordnungen der Dots und einer Variation bzgl. des optionalen Weißanteils W;
• 5 gemäß beispielhafter Ausführungsformen eine 2D-Darstellung (a/b Koordinaten ohne Helligkeitsanteil L) eines nutzbaren Farbraums;
• 6 eine beispielhafte Ausführungsform für den Aufbau eines den Dokumentenkörper bildenden Laminats 8 mit einer in Rastergrafik auf einem Kernsubstrat ausgeführten Ausgangsmarkierung;
• 7 eine weitere beispielhafte Ausführungsform für den Aufbau eines den Dokumentenkörper bildenden Laminats 8 mit einer in Rastergrafik auf einem Overlay-Substrat ausgeführten Ausgangsmarkierung;
• 8 gemäß beispielhafter Ausführungsformen die chemischen Strukturformeln für zwei verschiedene Zustandsformen des photochromen Farbstoffs (Leuko-Farbstoffs) Oxazin;
• 9 gemäß beispielhafter Ausführungsformen einen laserinduzierten Farbwechsel („Umschalten“);
• 10 gemäß beispielhafter Ausführungsformen eine Desintegration von Farben der Ausgangsmarkierung;
• 11 gemäß beispielhafter Ausführungsformen ein Ausblenden von Anteilen der Ausgangsmarkierung;
• 12 gemäß beispielhafter Ausführungsformen eine Farbtondefinition von Farbflächen der Zielmarkierung;
• 13 Grauwertdefinition beim klassischen CMYK-Bild;
• 14 gemäß beispielhafter Ausführungsformen eine erste Variante zur Farbtongebung für die Zielmarkierung;
• 15 gemäß beispielhafter Ausführungsformen eine zweite Variante zur Farbtongebung für die Zielmarkierung;
• 16 gemäß beispielhafter Ausführungsformen überlappende Farbschichten der Ausgangsmarkierung;
• 17 gemäß beispielhafter Ausführungsformen die Definition verschiedener darstellbarer Farben ausgehend von der Ausgangsmarkierung aus 16
• 18 gemäß beispielhafter Ausführungsformen einen vorlaminierten Schichtenstapel (Folienpaket);
• 19 gemäß beispielhafter Ausführungsformen die Integration eines vollflächigen Schichtenstapels (Folienpaket) in das Laminat;
• 20 gemäß beispielhafter Ausführungsformen die Definition verschiedener darstellbarer Farben ausgehend von der Ausgangsmarkierung mit Schichtenstapel aus 19;
• 21 gemäß beispielhafter Ausführungsformen die Integration eines nicht vollflächigen Schichtenstapels (Folienpaket) in das Laminat;
• 22 gemäß beispielhafter Ausführungsformen die Integration einer Deckschicht in das Laminat;
• 23 gemäß beispielhafter Ausführungsformen die Integration eines nicht vollflächigen Schichtenstapels sowie einer darüberliegenden Deckschicht in das Laminat;
• 24 gemäß beispielhafter Ausführungsformen die Integration eines Clear Windows mit metallischer Deckschicht in das Laminat;
• 25 gemäß beispielhafter Ausführungsformen die Integration eines Clear Windows mit metallischer Deckschicht und darunter liegender Ausgangsmarkierung in das Laminat;
• 26 gemäß beispielhafter Ausführungsformen die Integration eines Clear Windows mit zwei metallischen Deckschichten und dazwischen liegender Ausgangsmarkierung in das Laminat;
• 27 gemäß beispielhafter Ausführungsformen einen schematischen Ausschnitt einer mit verschiedenen Bearbeitungsmethoden einschließlich der Herstellung eines Schwarzanteils aus der Ausgangsmarkierung gewonnenen Zielmarkierung zur Darstellung eines kompletten Farbbildes; und
• 28 schematisch gemäß beispielhafter Ausführungsformen eine Vorrichtung zur Ausführung des Verfahrens.

This shows:

• 1 schematically different exemplary embodiments (variants) of an initial marking, each executed as a raster graphic on a base substrate;
• 2 according to exemplary embodiments, each schematically (a) a raster graphic consisting of several raster points (dots), each forming a subpixel. 1(a) , constructed pixel, (b) a pixel constructed from several line segments, each forming a subpixel, (c) a raster graphic constructed from line segments with the colors CMY, and (d) a raster graphic constructed from line segments with the colors CMYW;
• 3 and 4 According to exemplary embodiments, to illustrate different color saturations, an exemplary comparison of two different raster graphics is shown, both in macroscopic view ( 3 ) as well as in microscopic view ( 4 ) and each using the primary colors C, M and Y, but with different arrangements of the dots and a variation regarding the optional white component W;
• 5 According to exemplary embodiments, a 2D representation (a/b coordinates without brightness component L) of a usable color space;
• 6 an exemplary embodiment for the construction of a laminate 8 forming the document body with an initial marking executed in raster graphics on a core substrate;
• 7 another exemplary embodiment for the construction of a laminate 8 forming the document body with an initial marking executed in raster graphics on an overlay substrate;
• 8 According to exemplary embodiments, the chemical structural formulas for two different states of the photochromic dye (leuco dye) oxazine;
• 9 according to exemplary embodiments, a laser-induced color change ("switching");
• 10 According to exemplary embodiments, a disintegration of colors of the initial marking;
• 11 According to exemplary embodiments, a hiding of portions of the initial marking;
• 12 According to exemplary embodiments, a color tone definition of color areas of the target marking;
• 13 Gray value definition in a classic CMYK image;
• 14 According to exemplary embodiments, a first variant for color shading for the target marking;
• 15 According to exemplary embodiments, a second variant for the color shading of the target marking;
• 16 According to exemplary embodiments, overlapping color layers of the initial marking;
• 17 According to exemplary embodiments, the definition of various representable colors starting from the initial marking. 16
• 18 according to exemplary embodiments, a pre-laminated stack of layers (film package);
• 19 According to exemplary embodiments, the integration of a full-surface layer stack (film package) into the laminate;
• 20 According to exemplary embodiments, the definition of various representable colors starting from the initial marking with layer stacks made of 19 ;
• 21 According to exemplary embodiments, the integration of a non-full-surface layer stack (foil package) into the laminate;
• 22 According to exemplary embodiments, the integration of a top layer into the laminate;
• 23 According to exemplary embodiments, the integration of a non-full-surface layer stack and an overlying top layer into the laminate;
• 24 According to exemplary embodiments, the integration of a clear window with a metallic top layer into the laminate;
• 25 According to exemplary embodiments, the integration of a clear window with a metallic top layer and underlying starting mark into the laminate;
• 26 According to exemplary embodiments, the integration of a clear window with two metallic cover layers and an intermediate starting mark into the laminate;
• 27 According to exemplary embodiments, a schematic section of a target marking obtained using various processing methods, including the production of a black component from the initial marking, to represent a complete color image; and
• 28 A device for carrying out the method is shown schematically according to exemplary embodiments.

The following detailed description of the present solution is given with reference to the figures and on the basis of various exemplary explanations, using numbered headings to structure the description, which, however, are in no way to be understood as a limitation of the solution.

In the figures, identical reference symbols denote identical, similar, or corresponding elements. Elements depicted in the figures are not necessarily shown to scale. Rather, the various elements depicted in the figures are represented in such a way that their function and general purpose are understandable to a person skilled in the art. Connections and couplings between functional units and elements shown in the figures can, unless expressly stated otherwise, also be implemented as indirect connections or couplings.

1. Starting marker

1 illustrates a process within an exemplary procedure for producing a document body having a multi-layered laminate, generating a multi-colored marking inside the laminate that represents data.

More precisely, it shows 1 Four different variants (a) - (d) of an initial marking 1 produced by the process in or on an extensive substrate, such as a film-like plastic substrate (e.g., made of polycarbonate, PC). In each variant, the initial marking 1 is implemented as a raster graphic 9 and has several colored sub-areas 3 – hereinafter also referred to simply as “dots” – C, M, Y, such that the colors of at least two of the sub-areas (dots) 3 differ from each other. In the present example, each of the raster graphics contains, according to the CMY color space, a cyan dot C, a magenta dot M, and a yellow dot. Y. In variants (a) to (c) from 1 In addition, there is always a non-colored sub-area 3, which is defined by the color of the base substrate, which in this example is white, resulting in a white dot W. With a transparent base substrate, this dot is also transparent instead of white (but is still labelled "W" here).

Within the raster graphic, the various dots C, M, Y and, if applicable, W are combined to form a periodically repeating pattern 2 consisting of three dots C, M, Y, or, if W is present, four dots C, M, Y, W. Depending on the raster definition, the pattern 2 can take on different shapes (envelopes) and can be rectangular (especially square, see variants (a) and (c)), diamond-shaped (see variant (b)) or triangular (see variant (d)).

To produce the initial marking, the colored dots, in this example dots C, M and Y, can be applied to the base substrate, in particular by means of a suitable printing process.

Instead of dots 3, the initial marker 1 can also be composed entirely or partially of other, i.e., non-circular, image elements. Examples of such other image elements include, in particular, polygonal, elliptical, or any other shaped dots or line segments.

2 (a) shows an example of a raster graphic consisting of several (circular) dots, each forming a subpixel. 1(a) , constructed pixel 4, which can correspond in particular to the associated pattern 2. Pixel 4 can be understood as a picture element of a raster graphic, where the individual dots C, M, Y, and W of pixel 4 each form a subpixel of the associated color. As will be explained in more detail below, by selectively using the dots, the color of pixel 4 can be represented from a multitude of different colors from the CMY(W) color space.

Specifically, according to the above-mentioned variants (a), (b) and (c), the respective raster graphic can be generated in particular by printing circular or square color areas (dots) 3 in the colors cyan (C), magenta (M) and yellow (Y), e.g. with a dot diameter d ≤ 150 micrometers (µm), onto a transparent or opaque, in particular white, substrate.

Variant (d) uses almost exclusively cyan, magenta, and yellow. Therefore, to avoid adhesion problems during the subsequent lamination of the base substrate with a further substrate covering the dots 3 on the base substrate, it is advantageous to use a separate polymerizing color that bonds with the further substrate, which can be made of polycarbonate, during lamination. In the other variants, this can be achieved effectively using the white area W alone, although polymerizing colors for the colored dots C, M, and Y can optionally be used as well. Taken together, the different colored dots 3, grouped into pixels 4, provide a variable basic arrangement of pixels 4, each of which can, for example, have a pixel diameter D ≤ 363 µm.

• Auflösung in der Breite: $\text{DotsB}=\frac{25400\frac{\mu m}{inch}}{30\frac{\mu m}{dot}}\approx 847\text{ dpi}$
• Auflösung in der Höhe: $\text{DotsH}=\frac{25400\mu m}{30\mu m\cdot \mathrm{0,87}}\approx 973\text{ dpi}$

The following is an example of how to resolve the color image according to the triangle arrangement from variant (d) of the 1 For a dot diameter d = 30 µm and a correction factor F _K = 0.87 for the triangular matrix arrangement versus the rectangular matrix according to variant (a), the following resolution in height is calculated:

• Resolution in width: $\text{DotsB}=\frac{25400\frac{\mu m}{inch}}{30\frac{\mu m}{dot}}\approx 847\text{ dpi}$
• Height resolution: $\text{DotsH}=\frac{25400\mu m}{30\mu m\cdot \mathrm{0,87}}\approx 973\text{ dpi}$

The arrangement of the different colored dots 3 in the raster graphic is variably selectable - e.g. CMY / YMC / MCY / etc. By including the variant-dependent white component W in the possible arrangement variety in the raster, a large number of raster graphics can be realized as the respective starting mark 1.

In 2 (b) As a further embodiment for designing the raster graphic, a different form of pixel 4 is shown, which instead of circular sub-areas 3 has adjacently arranged line segments. Otherwise, the above applies. 2A Said accordingly.

In 2(c) The entire raster graphic, shown here in the CMY color space, is constructed from parallel, differently colored parallel line segments, with pixel 4 of the raster graphic marked by its dashed perimeter for illustration purposes.

2(d) corresponds 2(c) by adding another color (white, W) to the color space, resulting in a CMYW color space in the given example.

The 3 and 4 This shows an example where two different raster graphics are placed side by side for comparison. This shows 3 a macroscopic view 5 of the raster graphics, as a viewer would perceive them with the naked eye, while 4 A microscopic view 5 of the raster graphics shows the individual dots 3 and their arrangement clearly visible.

The raster graphic from 3(a) or 4(a) shows according to a modification of variant (a) 1 Regarding the color sequence, a YM(W)C arrangement (color sequence clockwise starting with dot Y in the upper left) is used, thus including a white component W in addition to the primary colors CMY. The raster graphic from 3(b) or 4(b) In contrast, variant (d) shows 1 a CMY arrangement with alternating color sequence along the pixels of a row and therefore no white component W in addition to the basic colors CMY.

It is even in the black and white representation derived from the actual color representation in 3(a) It is clearly recognizable that the changed position of the dots 3 relative to each other and the variation regarding the white content in the initial marking 1 result in a visible distinction under standardized conditions (distance = 0.5 m; viewing angle = 45°; D50 standard illuminant). In particular, the initial marking 1 appears 3(b) due to the lack of white W and the higher dot density, darker than the initial marking 1. 3(a) .

Extending the analysis to include all variants (a) to (d) from 1 , it becomes apparent that the color saturation varies considerably. In variant (a) it is 59%, in variant (b) 71%, in variant (d) 75%, and in variant (d) even 91% (see below). 3(b) ). The very high color saturation in variant (d) or 3(b) This requires the use of special polymerizing inks, which bond to the base substrate (e.g., polycarbonate) during lamination. The use of these inks is helpful, or may even be necessary depending on the choice of base substrate and colors, to meet the relevant standards for peel strength in security documents, especially passports or other identification documents (e.g., identity cards).

The distances between the dots 3 are in the triangular arrangement made up of 3(b) or 4(b) constant (x) (similarly also in the parallelogram arrangement from variant (b) of the 1 ), whereas the distances in the square arrangement are made up of 3(a) or 4(a) (similarly also in the square arrangement from variant (c) of the 1 ) vary (y > x). Therefore, exchanging the colors in the square grids has a greater influence on the initial color tone. This is significant because, when the arrangements are changed, even the viewing angle of the initial marker 1 leads to a correspondingly different perception. The theoretically most homogeneous variant among those from 1 (and overall for circular dots of the same size) is variant (d) from 1 followed by variant (b) from 1 .

5 According to an exemplary embodiment, a 2D representation 7 (a/b coordinates without brightness component L) of a color space and of variant-specific usable color space sections thereof. With regard to the variants from 1 Variant (d) (followed by variant (c) and variant (b)) offers the largest usable color space section due to the increased color content and the associated color value boundaries a (green-red) and b (blue-yellow). These color boundaries a, b and the brightness component L (not in 5 The parameters shown (in the diagram) together define the usable color space segment. The size of this color space segment is also referred to as the "gamut." However, the higher the color coverage, the lower the peel strength typically is. Depending on the specific requirements, which are usually application-dependent, a workable, ideally optimized, compromise must generally be found between the selection of color components on the one hand and mechanical resistance on the other (compromise case), unless both requirements can be optimally met simultaneously in a particular case (consensus case). Variant (b) from 1 is an example of such a compromise or even consensus (depending on applicable requirements), since on the one hand a high area coverage can be achieved through the diamond arrangement with offset dot rows and on the other hand good peel strength can be achieved via the white content W (i.e. particularly good adhesion to the layer above).

2. Laminate or lamination

In the process for producing a document body comprising a multi-layered laminate (monoblock) and generating a multi-colored, data-representing marking within the laminate, the laminate is created by laminating the base substrate as the first laminate layer with at least one further, planar substrate as each subsequent laminate layer. This is done in such a way that the initial marking is located at least partially within the interior of the produced laminate.

The 6 and 7 Two different exemplary embodiments for the construction of a laminate forming the document body are shown here 8.

In 6 An embodiment is shown in which a raster graphic 9 (colored components, color matrix) is applied or incorporated directly onto or into a core substrate 10 of the document body to be formed to generate the initial marking 1. The core substrate 10 can be, in particular, completely or partially opaque, and may also include one or more transparent or semi-transparent windows (not shown). It can, in particular, be designed as a film. For example, it can be the core layer of a document body that is designed as the data page of an identity document. If a white component W is provided in the initial marking 1, this can thus be represented by the core substrate 10 itself, which is not covered by the colored components of the raster graphic 9 at the corresponding white component dots. The core substrate 10 may, in particular, have the same or greater thickness than the overlay substrates 11. The overlay substrates 11 are generally fully or partially transparent to allow the initial marking to be seen from outside the laminate, although the various possibilities for making the marking produced by the process visible inside the laminate 8, as explained below, may be used.

The core substrate 10, marked with raster graphic 9, is or is in 6 The laminate 8 is supplemented on both sides by two stacked overlay substrates 11. The lamination can be conveniently carried out by stacking the substrates 9, 10 and 11 on top of each other, as shown in 6 depicted and subsequent lamination under pressure and/or temperature influence.

In 7 A further embodiment is shown in which, for generating the initial marking 1, a raster graphic 9 (colored components, color matrix) is not, or at least not completely, applied directly to the core substrate 10 of the document body to be formed. Instead, the raster graphic 9 (colored components) is applied to or embedded in one of the overlay substrates 11. Otherwise, it corresponds to 7 to which already 6 explained the structure.

In order to achieve a high level of adhesion between the colored areas of the initial marking 1 and the base substrate 10 and/or the immediately overlying overlay substrate 11, it is possible to select the base substrate 10 or the overlay substrate 11 such that it contains a polymer material as a component or is entirely composed of it, and that at least one of the colorants used in the production of the initial marking 1 is a polymerizing color that is selected in such a way that it forms a polymeric bond with the respective substrate 10 or 11 during lamination.

3. Multicolor marking and its production

Starting with the laminate 8 containing the initial marking 1, a desired multicolored marking 15 (hereinafter also referred to as the "target marking") can be generated by spatially selective energy input into the initial marking 1. The energy input can be achieved, in particular, by means of a laser through laser radiation acting on the initial marking 1. Various process variants for producing the target marking from the initial marking 1 are described below as examples. These variants can be carried out either individually or in any combination (provided they are possible without contradiction). For example, various Sections of the initial marking 1 can be selectively and simultaneously or sequentially processed by different method variants to generate the target marking. Some of these combinations are described in more detail in Section 3.7, although it should be understood that the possibility of combining method variants is not limited to these specific combinations.

In all laser processing applications described herein, an ultrashort pulse (USP) laser can be used, in particular, to effect the locally selective energy input into the initial marking 1. The aim is to ensure that the radiation emitted by the laser, or a radiation pattern generated by locally varying the laser radiation, corresponds to the structures of the initial marking, especially to the arrangement of dots within it, in such a way that targeted dot-by-dot irradiation can be achieved. USP lasers typically have pulse durations in the picosecond or femtosecond range. The pulse width can thus be, for example, only 0.3 µm.

During laminate production, slight deformation of the resulting laminate compared to a perfectly flat surface often occurs during lamination. Consequently, the initial marking may also be subject to deformation (distortion compared to the ideal flat state). Such distortion typically varies from laminate to laminate (i.e., it is usually document-specific), making laminate- or document-specific distortion compensation advisable. This individualized compensation can be achieved, in particular, by analyzing an image of the laminate or document and subsequently adapting a parameterized compensation model.

To perform distortion correction, a locally selective first energy input pattern, intended as the target pattern for energy input, is modified before or during the energy input process so that the irradiation is based on a second energy input pattern resulting from the distortion correction. The second energy input pattern is derived from the first energy input pattern based on correction information determined by a deviation of the actual shape of the produced laminate from a target shape defined for the laminate, which is detected automatically, particularly by sensors. A compensation method of this type, also applicable in the present context, is described in the DE 10 2022 209 198.1 described by the applicant here.

3.1 Switching of leuco dyes

One or more of the colors can be caused at least partially by colorants that are or become a leuco-dye, which, through the input of energy at the point of its action on the leuco-dye, can be switched between a colored and a differently colored state or an opaque and an at least partially transparent state, or vice versa.

The energy input into the laminate 8 can thus be effected, in particular, by acting in a locally selective manner at the location of the initial marking 1, whereby the multicolored marking representing the data (target marking) is generated, at least partially, from the initial marking 1 by means of the locally selective switching of the leuco dye caused by the energy input into the initial marking 1. It is particularly possible that the creation of the target marking occurs solely through such a switching of the leuco dye in the initial marking 1, or in combination with one or more of the possibilities described below (from paragraph 3.2 onwards).

To understand how leuco dyes work, a basic explanation of their chemical structure using a (non-restrictive) example is helpful.

8 (based on a representation from [1]) shows, by way of example, the respective chemical structural formulas 12 or 13 for two different states of the photochromic dye (leuco dye) oxazine, wherein the two forms 12 and 13 can be reversibly converted into each other by UV irradiation or heating.

The in 8 (a) The depicted spiro form 12 of an oxazine is a colorless leuco dye. The conjugated system of oxazine and another aromatic part of the molecule is separated by an ^sp³ -hybridized "spiro" carbon. Upon irradiation with UV light, the bond between the spiro carbon and the oxazine breaks, the ring opens, the spiro carbon achieves ^sp² hybridization and becomes planar, the aromatic group rotates, aligns its π-orbitals with the rest of the molecule, and the structure shown in Figure 12 is formed. 8 (b) depicted conjugate system with the ability to capture photons of the visible spectrum to absorb light and therefore appear colored (colored form 13 of oxazine). When the UV source is removed, the molecules gradually relax to their ground state, the carbon-oxygen bond reforms, the spiro carbon is re-hybridized to ^sp³ , and the molecule returns to its colorless state (see [1]).

This class of photochromes, in particular, is thermodynamically unstable in one form and reverts to its stable form in the dark unless cooled to low temperatures. Their lifetime can also be affected by exposure to UV light. Like most organic dyes, they are susceptible to degradation by oxygen and free radicals. Incorporating the dyes into a polymer matrix, adding a stabilizer, or providing a barrier to oxygen and chemicals by other means extends their lifetime (see [1]).

These are amine compounds (nitrogen compounds) that have the ability to change color by altering their state. However, this only occurs through external excitation, meaning that mechanical and/or thermal energy is required to trigger the color change.

Since the color change is achieved in different ways, leuco dyes can be subdivided according to the type of external excitation as follows: • Halochrom → change in electric charge ΔQ _e • Photochrom → Light exposure - illuminance E • Piezochrom → Energy input through pressure change Δp • Thermochrom → Temperature change ΔT

Photochromic leuco dyes are particularly well-suited for the present solution. They allow a color change to be achieved through photonic energy input – for example, as already mentioned, using a laser.

9 Figure 14 illustrates an example of such a laser-induced color change (“switching”) starting from an initial marking 1 designed as a raster graphic 9. In particular, a laser 16 can be used to process the color areas of the raster graphic 9 in order to switch individual colored dots 3 (e.g. C, M or Y), i.e. selectively a true subset of the dots 3 coated with leuco dye ( 9(a) ) (Of course, in a limiting case, switching all dots is conceivable, but in real-world applications this is usually not practical). The selective switching of dots 3 thus takes place, at least primarily, inside the laminate 8, where in ( 9(b) As an example, two different raster graphics 9 are shown side by side but at different depths within the laminate, each of which can be considered individually or cumulatively as the initial marker(s) 1. The same laser 16 can be used to process both raster graphics 9, but its focal length is advantageously adjusted to match the respective distance of the raster graphic 9 so that the focus of the laser beam is on the respective raster graphic 9.

Using the laser 16, the leuco dye is applied to the selectively selected dots 3 (for marking in 9 (shown with a thick border) photonically excited from the outside to induce a molecular change in the dye, as described above, and thus a modified raster graphic corresponding to the target label 15 ( 9(c) ) to bring about. This is based on the molecular structure. 8 (a) If the energy input is large enough, the oxazine bond breaks, whereupon the molecular structure changes as in 8 (b) The representation changes, and with it the absorption behavior also changes. In the leuco state 12 (colorless), the entire spectrum of spectral colors is absorbed.

After the energetic processing and the associated structural change, only the colors defined beforehand during development are absorbed. Those colors that do not fall within the absorption spectrum are reflected and thus visible to the human eye. Depending on the development specifications and the resulting color composition, theoretically all colors can be represented.

3.2 Color Disintegration

According to another possibility for producing the target marker 15 from the initial marker 1, as described in 10 illustrated, a laser 16 is used to process the colored areas of the raster graphic 9 of the starting mark 1 ( 10 (a) ), in order to disintegrate individual colored dots 3 (e.g., C, M, or Y), i.e., selectively a true subset of the dots (in the limiting case, the disintegration of all dots 3 is also conceivable). Such selective disintegration 18 of dots 3 thus takes place, at least mainly, in the interior of the laminate 8.

The terms “disintegration” and “disintegrate”, as used herein, refer to a radiation-induced color-relevant transformation or removal of the dyes from affected color areas, which may in particular involve color abrasion or destruction of the dyes.

Since the target marking 15 to be produced is intended to be visible to an observer of the laminate 8 or the finished document body formed from it, the disintegration takes place in a transparent area of the laminate 8 or in an area of the laminate 8 that has been made transparent by subsequent processing. The laminate 8 can, in particular, consist entirely or partially of transparent polycarbonate as a material to create the transparency. For the purpose of disintegration, the laser radiation 17 can selectively introduce energy to locally generate very high temperature peaks in the initial marking 1, thus causing a locally limited dissolution or conversion of the dyes in the irradiated dots 3 of the initial marking 1. Such laser irradiation into the interior of a substrate (here, laminate) is also referred to as a sub-surface laser processing process (SSLE).

The color in the dots 3 of the starting marker 1, more precisely the raster graphic 9 ( 10 (b) ), is completely or partially removed during disintegration by the laser radiation 17 ( 10 (c) The paint preferably has a defined layer thickness to simplify laser control and, in particular, to enable a constant irradiation time for each area to be treated (given a specific radiation energy). Disintegration, especially the complete or partial removal of the paint, can be achieved using a microshort pulse (USP) laser. The ultrashort, intense light pulse can be used to vaporize the targeted material at specific points, which can be used to create high-precision structures. Furthermore, the high locality and short duration of the energy input minimize the temperature load in the immediate vicinity. This makes it possible, in particular, to process micrometer-thin or heat-sensitive materials, and even transparent materials absorb the high-intensity light pulses.

By selectively "switching off" the color in this way, the substrate, i.e., the laminate layer, on or in which the color was applied to create the initial marking 1 (base substrate), becomes visible. In the example of the 6 Thus, at the laser-processed areas, the core substrate 10, which lies beneath the color layer of the raster graphic 9 and serves as the base substrate, becomes visible; this substrate may be opaque. This leads to visual changes at the respective location, so that the resulting target marking 15 is modified accordingly compared to the initial marking 1.

The selective removal of the colors allows, in particular, the appropriate coloring of the immediately underlying substrate (10 in 6 or 11 in 7 The laser also enables the representation of very bright hues, thus expanding the possible color spectrum. The colored areas (dots 3) of the initial marking 1 can be formed on/in a transparent or a white/opaque substrate and selectively ablated there by the laser radiation 17. By appropriately adjusting the focal length of the laser 16, the energy input can be focused on the colored layers in order to limit the disintegration of material essentially to the colored layers of the initial marking 1.

3.3 Complete or partial hiding of portions of the initial marking

In addition to the aforementioned color disintegration, it is also possible, either instead or cumulatively, to shape the coloration of the desired target marking 15 visible to the viewer by thermal and/or photonic excitation of a physical or chemical local change in the laminate in one or more overlying layers overlapping the initial marking 1.

This is in 11 The 19th part of the initial marking 1 is exemplified by the hiding of these parts. In particular, with some materials, such as polycarbonate, a chemical reaction can be triggered by the local energy input, which causes small bubbles or nodes 20 or similar features to form at the point of energy input, thereby changing the local refractive index of the material at that location (see Figure 1). 11 ). In this way, the initial marker 1 can be locally “hidden” for the viewer, i.e., its visibility can be selectively reduced or even eliminated.

For example, in polycarbonate, the section of the output marker 1 located below the point of energy input (e.g., one or more dots or entire pixels) can be masked by bubble formation in such a way that only a white, or more specifically, a milky-looking dot is visible to the observer in place of the output marker 1. In this case, the working or focal plane of the laser is expediently placed at a location above the output marker 1, i.e., at a location between the laminate surface and the output marker 1.

The terms “above”, “below”, “over”, “above”, “below”, “between”, etc., used herein in relation to the arrangement of the initial marking 1, laminate layers, focal planes or locations of energy input, etc., are always to be understood as referring to a horizontally lying laminate from the top of which the initial marking 1 and the derived target marking are or are intended to be wholly or partially visible to an observer in a top view.

3.4 Tint levels

The previously presented possibilities for processing the initial marking 1 can be implemented in such a way that the processing (especially irradiation) of individual dots 3 is only partial, i.e., area-proportional per dot 3, at least for a subset of the dots 3. The initial marking 1, especially raster graphic 9 (e.g., CMYW base matrix), can be designed unchanged as described above (see especially Section 1 above).

The locally selective energy input is implemented, for example, at least with regard to one or more dots 3, and in particular section by section for one or more sections of the initial marking 1, each containing a plurality of dots 3 or pixels 4, such that only partial areas of a single dot 3 are irradiated by the laser radiation 17 and thereby, in particular, “switched”, “ablated”, or “blocked out” (see sections 3.1 to 3.3 above). This is in 12 This is illustrated by way of example for a single yellow dot 3 (Y), whose colored area in the white-depicted point-like sub-areas 22 has been selectively processed, in particular by being irradiated with laser radiation 17 or by irradiating a spatial area in the laminate 8 above it in accordance with section 3.2, and thus differs in color from the unprocessed area 23 of the dot 3. In particular, the processed sub-areas 22 can assume a white color (W).

Considering the example of 12 If you examine dot 3 under magnification, you can see a distinction between white (W) and yellow (Y). However, the human eye perceives dot 3 as a lighter shade. This method makes it possible, in particular, to represent different tint levels (hues) 23. Therefore, for example, in the CMY(W) color space, the color channels C, M, and Y can each be viewed as a tint level image (in the conventional black-and-white color space, this would be a grayscale image), such as an 8-bit grayscale image (e.g., from white to yellow).

Likewise, by combining several individual color channels (each tint level 23 (e.g. defined by a tone value from the value interval [0,...,255] spanned by 8 bits) it is possible to generate detailed and color-accurate images.

According to one approach, a method can be used that is particularly suitable for CMY(K) images (with or without a K component). First, let's consider the structure of a classic CMYK image, as shown in 13 An example illustration shows that such an image consists of a dot matrix where the tint levels or tonal values are determined by the spot size of the colored dots (upper part of the image in...). 13 , microscopic view). However, the unarmed human eye does not perceive the spots themselves at these typically small spot sizes, but only a homogeneous color tone overall (lower part of the image in 13 , macroscopic view) true.

The first variant for color grading, which builds upon this, is in 14 illustrated. The initial marking 1 contains one for each primary color (in the example CMYK color space, that is, one for each color C, M, Y, and K). own primary-colored dot grid. These dot grids are additively combined to form the initial marking 1, whereby, however, in order to achieve a largely homogeneous color thickness, the individual dots (unlike in 14 An alternative is shown where points may partially overlap, and in particular, where points may be arranged in groups of pixels 4 that do not overlap. Points C and MY can be understood as dots 3 of the initial marking 1, which in this example also contains points of color K.

As described above, the desired color tones for C, M and Y can now be obtained from the initial marking 1 by a locally selective energy input using the laser radiation 17, whereby one or usually several of the dots 3 are in particular “switched”, “ablated” or “blinded” (see sections 3.1 to 3.3 above).

Specifically, the points of color K can be generated by locally selective carbonization of a material within the laminate 8 using laser radiation 17, particularly a polymer material. The carbonization can occur, in particular, on or within the layer of the laminate that carries the initial marking 1. The irradiation can be carried out with variable irradiation intensity and/or duration such that the degree of carbonization at the respective point of irradiation within the polymer material is variable with respect to the proportions of the initial marking 1 (and the derived target marking 15) formed by the irradiation, thus defining the tonal value for color K.

According to a 15 In the illustrated second variant for color shading, a method can be used that is particularly suitable for RGB images. The image, or target marking 15, is constructed from individual tint level images 25 for each primary color (red (R), green (G), and blue (B)). For each primary color, starting from a classically assigned grayscale image 24, the color tone "black (S)" is replaced by the respective primary color (R, G, or B). By overlapping the tint level images 25 obtained in this way for each primary color, a color space (RGB) is created that encompasses a multitude of different representable hues, which can be used to represent the target marking 15. The different tint levels 23 can be defined by the variable area proportion of the sub-areas 22 to the total area of the respective dot 3, determined by the selectable irradiation.

The upper part of the 15 The first part of the figure illustrates the principle of the second variant using a simple example 8 × 8 dot matrix, while the lower part of the figure shows a concrete example (with much higher resolution).

3.5 Selective exposure of superimposed paint layers

In the image design options described above in paragraphs 3.1 to 3.4, a side-by-side arrangement of the color areas (e.g. Dots 3) of the different colors is useful, so that an overlap of the color areas is not necessary or can even be deliberately avoided, for example to ensure a largely homogeneous color layer thickness.

In the following, further image design option for target marker 15, an overlap of colors is deliberately used. This option is available in the 16 and 17 This is illustrated. Here, the colored areas, each representing one of the primary colors of a desired color space, e.g., CMY, are arranged flatly on top of each other. The two variants "print" and "layer stack," explained below, are particularly suitable for this purpose.

3.5.1 Printing

In this process, the three primary colors C, M, and Y of the CMY color space are printed in the image area, particularly across the entire surface, in one of several possible configurations onto a core substrate 10. Here, it can again be advantageous to use special printing inks that exhibit high cohesive or adhesive forces to the adjacent layers (core substrate 10, overlay substrate 11, or adjacent color layers), so that they meet the relevant application-specific requirements, especially standards, for peel strength. Such special printing inks can be formulated to contain an adhesive as an additive, in addition to one or more dyes and, optionally, other components (e.g., a binder).

The colors are, at least largely, opaque and therefore overlap each other in their overlapping areas. If the top/last color layer is magenta (M), for example, a magenta area, e.g., a rectangle, will be visible (see figure). 16 ). Due to a predefined, small thickness z of the color layers, it is possible to integrate the colored image area into the document body (laminate 8) without embedding/cavity in one or more adjacent laminate layers.

To generate the desired color image of the target marking 15, a laser 16 can again be used for locally selective disintegration of the colors. For this purpose, the processing depth of the color disintegration is adjusted via the irradiation intensity, the irradiation wavelength(s) and/or the irradiation duration so that the desired color (i.e., the corresponding color layer) is exposed at the respective processed area. This is in 17 This is illustrated in more detail below. For example, to create a cyan pixel at a specific location within the image area, local irradiation is applied to achieve a processing depth y1, thus exposing the cyan layer point by point. The same applies to yellow pixels at a processing depth y2. At a processing depth y3, all three color layers are disintegrated, revealing the color of the underlying substrate (e.g., core substrate 10), which in the illustrated case is white (W). Where irradiation does not occur, the color of the uppermost color layer, in this example M, is retained. Overall, a CMYW color space is available for generating a colored target marker 15 (viewed from above).

3.5.2 Layer stack

In addition to printing technology, it is also possible to form or use the color layers as correspondingly colored substrates, especially films, to provide the superimposed color layers as a starting mark 1 or part thereof, and to incorporate these differently colored substrates (e.g., again in colors M, C, and Y) as layer stacks 26 stacked on top of each other into the laminate 8, especially as a pre-laminated film package, as in 18 The pre-lamination process (e.g., more generally, a stapling process) is illustrated here by showing the compression forces F acting during pre-lamination. The layer stack 26 can, in particular, extend over the entire surface of the laminate, as shown in the 19 and 20 illustrated. For example, each color layer (e.g., color film) of the layer stack 26 can have a thickness of ≤ 100 µm.

Here too, a locally selective energy input, for example again by means of laser radiation 17, serves to disintegrate color at the respective location of the initial marking 1 in order to penetrate down to the desired color layer of the layer stack and expose this color layer. This is in 20 illustrated.

Additionally, a white opaque layer may be provided, particularly as the bottom or top layer, which is part of the layer stack 26 itself or in addition to it, to extend by the white component.

Optionally, another color layer 27 can be applied above (as in the 19 and 20 (shown) or provided below the layer stack 26. It can, for example, serve as a fourth colored layer, e.g., of the color white (W), thus extending the available color space (e.g., CMY) accordingly (towards CMYW). Similarly, a black layer could be provided instead or additionally to supplement the available color space accordingly (towards CMY(W)K).

The additional color layer 27 can, however, be or may be formed as an optically variable layer, the color and/or degree of transparency of which can be locally changed by the spatially selective energy input at the point of impact of the energy input on the color layer 27. In this way, a locally selective masking of the (other) initial marking 1 can be formed, which can contribute proportionally to the definition of the target marking 15. The masking can, in particular, have opaque, semi-transparent and/or transparent sections.

In all the aforementioned cases, the layer stack 26 can extend only partially across the image area instead of covering the entire surface, as exemplified in 21 This is illustrated. For this purpose, the at least partially opaque core substrate 10 is provided with a cavity into which the layer stack 26, in particular as a pre-laminated film package, is inserted and welded. The result is a core substrate that is partially colored in the image area. The core substrate 10 itself can be, for example, white (W).

It is also conceivable, as in 21 As shown, a second core substrate 28 is additionally provided below the (first) core substrate 10. This is particularly advantageous if the cavity in the core substrate 10 extends through its entire thickness. To represent an additional color component (especially W), the layer stack 26 can be locally disintegrated through its entire thickness during the production of the target marking 15 to create an opening through which the viewer can see either the first core substrate (if the layer stack 26 does not extend through the entire thickness of the core substrate 10) or the second core substrate 28 (if the layer stack 26 does extend through the entire thickness of the core substrate 10), and thus the color of the respective core substrate 10 or 28 (here, for example, W), thereby contributing to the expansion of the color space (here by the color W).

The color removal (disintegration) process is analogous to the full-surface option. The order of the colors in this example differs with respect to color W compared to the previous option. 20 Changed (position at the bottom instead of at the top). Embedding the layer stack 26 in the image area is regularly more space-saving than the full-surface variant, since, with the same color space, one layer (layer 27) can be saved and the laminate 8 can therefore be made thinner.

However, it is also possible to use layer 27, similar to what was described above, to cover, in particular mask, the underlying layer stack 26, as in 22 Illustrated. To create the effect of removing individual color dots from the initial marking 1, it is possible, in addition to the direct laser treatment of the initial marking 1, to use layer 27 as a top layer (e.g., printing ink or film) on the image area and to apply this in a point-by-point and congruent manner (printing ink) over individual dots 3 or pixels 4, or to extend it over a large area (printing ink or film) over the entire surface of the initial marking 1.

Energy can now be supplied to the top layer 27 in a locally selective manner, particularly by means of laser radiation 17, in order to trigger a chemical reaction locally within the layer 27, which manifests itself as a color change, e.g., from transparent to white ("bleaching"). In this case, the layer 27 can be conveniently interpreted as a "bleach layer." The colors located beneath the treated areas are thus locally covered (masked) as a result of the energy input, becoming opaque or at least partially transparent.

• (a) Reaktive transparente Deckschicht - insbesondere Druckfarbe oder Folie Die Schicht 27 wechselt unter Laserbestrahlung 17 ihre transparente Struktur hin zu einem opaken Weiß (W). Die Ausgangsmarkierung 1 wird dadurch partiell abgedeckt (maskiert), wobei ein weißer Flächenbereich (Dot 3) des Bilds entsteht.
• (b) Reaktive opake Deckschicht - insbesondere Druckfarbe oder Folie Die Schicht 27 ändert aufgrund des lokalen Energieeintrags, z. B. unter Lasereinstrahlung 17, ihre opake Struktur in eine transparente. Die darunterliegende Ausgangsmarkierung 1 wird dadurch am Ort des Energieeintrags partiell sichtbar. Auch lässt sich so eine variable, insbesondere stufenlos wählbare Transparenz erzeugen. Anders ausgedrückt, es können mittels des „Bleachings“ zusätzlich Schattierungen oder verschiedene Farbtöne der darunterliegenden Farben erzeugt werden.

In particular, the following two possibilities arise for using this effect:

• (a) Reactive transparent top layer – in particular printing ink or film. Under laser irradiation 17, layer 27 changes its transparent structure to an opaque white (W). The initial marking 1 is thereby partially covered (masked), creating a white area (dot 3) of the image.
• (b) Reactive opaque top layer – in particular printing ink or film. Due to the local energy input, e.g., under laser irradiation 17, layer 27 changes its opaque structure to a transparent one. The underlying initial marking 1 thereby becomes partially visible at the point of energy input. Variable, in particular continuously selectable, transparency can also be created in this way. In other words, additional shades or different hues of the underlying colors can be created by means of "bleaching".

• Zum einen ist es möglich, beide Techniken kumulativ so zu verwenden, dass eine der beiden Techniken nur für einen oder mehrere erste Teilbereiche der Ausgangsmarkierung 1 oder der daraus erzeugten Zielmarkierung 15 und die andere Technik für einen oder mehrere von den ersten Teilbereichen verschiedene zweite Teilbereiche genutzt wird, also räumlich selektiv nebeneinander. Insbesondere können mit Leuko-Farbstoff versehene Teilbereiche Dots 3 einer Rastergrafik (vgl. 1) bilden, wobei zweckmäßigerweise in der Rastergrafik die Farbe der Grundfarbschicht, auf der die Rastergrafik ausgebildet ist, nicht als Dotfarbe vorkommt, da sie durch Umschalten der Leuko-Farbstoffe auf „transparent“ bereits sichtbar gemacht werden kann. Beispielhaft ergäbe sich somit bei einer gelben Grundfarbschicht eine C-M-(W)-Anordnung. Auf diese Weise lassen sich insbesondere Vorteile hinsichtlich eines einfacheren Aufbaus der Ausgangsmarkierung 1 oder ein geringerer Aufwand bezüglich der Entwicklung und Herstellung solcher Ausgangsmarkierungen erreichen.

The selective exposure of superimposed color layers can be used in various ways, especially in connection with leuco dyes (see section 3.1):

• Firstly, it is possible to use both techniques cumulatively in such a way that one of the two techniques is used only for one or more initial sub-areas of the initial marker 1 or the target marker 15 generated from it, and the other technique is used for one or more second sub-areas different from the initial sub-areas, i.e., spatially selectively side by side. In particular, sub-areas marked with leuco-dye can be dots 3 of a raster graphic (cf. 1 ) are formed, whereby, advantageously, the color of the base color layer on which the raster graphic is formed does not appear as a dot color in the raster graphic, since it can already be made visible by switching the leuco dyes to "transparent". For example, a yellow base color layer would thus result in a CM-(W) arrangement. In this way, advantages can be achieved in particular with regard to a simpler design of the initial marker 1 or reduced effort in the development and production of such initial markers.

On the other hand, it is also possible to incorporate the leuco dyes into one or more of the superimposed color layers of the layer stack 26, so that irradiation not only exposes a corresponding color layer at each irradiation location (e.g., dot 3), but also switches its leuco color. Here, the initial marking 1 is thus at least partially produced as a layer stack 26 consisting of several differently colored, each opaque or semi-transparent, layers, of which one or more layers may contain one or more leuco dyes.

Layer 27 can also contain leuco dye, in particular, to enable it to switch between opaque and transparent (or vice versa). For example, with reference to the 16 and 17 The bottom (yellow) color layer Y in layer stack 26 can be made with conventional printing ink or colored foil, while the two color layers above it (C and M) contain switchable leuco inks. Of course, other combinations of layer structures with both conventional and leuco ink layers are also possible.

3.6 Selective color change of a top layer, masking

The use of a top layer (layer 27), in particular a bleach layer, has already been explained above with reference to embodiments with a layer stack 26. However, it is not limited to this, but can also be used, in particular, if the initial marking is formed according to one or a combination of several of the other embodiments described herein, for example, in the case of an initial marking produced by printing.

Layer 27 can be designed as a metallized layer, in particular a layer made entirely of metal, instead of being a bleached layer (see above). It can be made of a white or silver-colored aluminum material, so that in this case the initial marking 1 appears as a white, colorless surface before its post-processing. Another metal, such as tin, can also be used instead of aluminum.

A hot stamping process can be used, in particular, to apply the metal layer to the underlying initial marking 1. The procedure is the same as for processing a hologram. The metal, applied in an extremely thin layer to the substrate, is transferred to a layer for the laminate 8 – preferably a layer of transparent polycarbonate – using a preheated stamping tool and under high pressure.

The metallized document layer produced in this way can then be used in different forms within the laminate to create a security document.

All the variants with a metallic top layer described below have in common that the layer of the laminate 8 lying beneath the metallic top layer 27 is partially exposed. This condition is achieved by partially or completely removing the top layer 27 at desired locations using photonic radiation (in particular laser radiation 17).

The positioning of the cover layer 27 can take place directly on the initial marking. However, it is also possible to print the metallic cover layer 27 separately onto a separate substrate (e.g., film) in order to apply this substrate, coated with the cover layer 27, to the initial marking in a further step.

3.6.1 Metal layer combined with single-layer colored base marking

In this process, a pattern 2 (especially as a raster graphic 9) is first applied to a document layer (corresponding to a layer of the laminate) to produce the initial marking 1 from printing ink, in order to then be covered by the metallic layer 27 applied above it (cf. 22 ).

Once this arrangement is complete, a security feature can be created by selectively removing the metal through locally selective energy input and thereby exposing the underlying initial marking 1 - for example, a detailed pictorial representation of the document holder.

To increase the resolution, but also to bring out details better, one or more leuco dyes can be used, at least partially, to form the initial marking 1, which are then at least partially “switched”, as explained in more detail in section 3.1 above.

3.6.2 Metal layer combined with multilayer arrangement of leuco dyes

Instead of a single-layer color matrix – as described in section 3.6.1 – leuco colors, as in 23 illustrated, also in several layers below the metallic layer 27 into the document structure, in particular each covering the entire surface (see 19 This allows for a particularly high degree of variability in image display. Switching between the superimposed leuco colors may require electromagnetic radiation, especially laser radiation 17, of different wavelengths.

3.6.3 Metal layer in a window area

In a design known in technical language, among other things, as a "Clear Window", which in 24 As illustrated, transparent and opaque substrates (e.g., films) are combined in a layered structure. During manufacturing, a predefined geometric shape is cut into the opaque substrates as an opening 36, thereby exposing the transparent layers. In other words, this transparent area in the opaque substrates optically exposes all transparent layers of the multilayer structure that would otherwise be covered by at least one opaque layer. The opening 36 can preferably be created using a punch. The material removed in this process can optionally be completely or partially replaced (compensated) by a transparent polymer, in particular polycarbonate. However, if the volume of the removed material does not exceed a certain threshold, such compensation is generally not required. After the lamination process to produce the laminate 8, a transparent window (clear window) is formed in the area of the opening 36 or, optionally, in the overlap area of several such openings 36.

If the metallic layer 27 is used in conjunction with a clear window, it is possible to view the post-processed metal layer in transmitted light (illumination from the back). This can create an optical switching effect, which can be considered an additional security feature.

3.6.4 Metal layer(s) and colored initial marking in the Clear Window

Will now, as in 25 As illustrated, combining the three individual elements – clear window, metal layer, and colored starting mark 1 (color layer(s)) – results in several usable advantages. Firstly, by using at least one metal layer as a top layer 27 or 37 with an added upstream/downstream color layer, the basis for a color image in transmitted light can be created, which is not visible in reflected light, or only visible as a negative. "Reflected light" here refers to exposure from the viewing side, while "transmitted light" refers to exposure from the back.

Through the in 26 By using at least one second metal layer 37 (in addition to layer 27) on the opposite side, it is possible to use the transmitted light on the front and back of the laminate 8 (document body) in such a way that either the same pictorial representation appears on both sides or an optical representation independent of the opposite side can be implemented by means of laser engraving.

3.7 Generation of the black component using a grayscale laser

The various embodiments described so far have been explained with regard to the production of a multicolored, pictorial target marking 15 from a starting marking 1. If a black component is also desired in the image, this can be generated using a pulsed laser. Here, a high-energy light beam (laser beam) strikes a laser-reactive substrate (e.g., film) and leads to a local blackening of the substrate at the point of irradiation. Individual particles incorporated into the substrate carbonize during irradiation, thus resulting in a blackening of the material.

This type of processing for producing a black component can be implemented in multiple stages due to the variable radiation intensity/duration, making it particularly possible to create a detailed grayscale image. The black tone is expediently generated in a higher layer of laminate 8. If the initial marking is or will be printed on a transparent substrate, the blackening can also be applied in a lower layer of laminate 8.

Referring to those of the previously described embodiments of the initial marking 1, which are based on a raster graphic 9, this means that the colorless areas in the raster are or have been post-processed, i.e., the white spaces within the raster graphic or dots 3, which were partially or completely “whitened” beforehand.

27 This is shown as an example in the form of a schematic section of a target marker 15 to represent a complete color image. The raster graphic from served as the starting marker 1. 1 (a) , which has been modified in various ways according to some of the possibilities presented herein. For the purpose of a more detailed explanation, the dots 3 and spaces marked with arrows in 27 explained in more detail, although other parts of the target marker 15 were also changed compared to the initial marker during post-processing.

• - einen durch erhöhten Schwarzanteil leicht abgedunkelten Zwischenraum 29;
• - einen geweißten M-Dot 30, nachträglich durch Schwärzung vollständig abgedunkelt wurde;
• - einen durch erhöhten Schwarzanteil leicht abgedunkelter W-Dot 31;
• - einen durch Farbtönung (vgl. 12) aufgehellten M-Dot 32;
• - einen aufgehellten Y-Dot 33, der nachträglich durch Schwärzung abgedunkelt wurde
• - einen aufgehellten C-Dot, der nachträglich durch Schwärzung abgedunkelt wurde
• - einen geweißten Y-Dot 35.

In this example, the target marker specifically indicates:

• - a slightly darkened space 29 due to an increased proportion of black;
• - a whitened M-Dot 30, subsequently completely darkened by blackening;
• - a slightly darkened W-Dot 31 due to increased black content;
• - one through color tinting (cf. 12 ) lightened M-dot 32;
• - a lightened Y-Dot 33, which was subsequently darkened by blackening.
• - a lightened C-dot that was subsequently darkened by blackening.
• - a whitened Y-Dot 35.

28 schematically shows an exemplary embodiment of a device 38 according to the third aspect of the present solution, which is configured to carry out the method according to the first aspect,

The device 38 comprises a marking device 39, a laminating device 40, and a power source 41, which may in particular contain or be provided by the laser 16, connected in series along a process flow. Additionally, the device 38 comprises a control device 42, which is configured to cause the device 38 to execute the method according to the first aspect in order to produce the document body with data inscribed therein.

The marking device 39 is configured to produce an initial marking 1 on a planar base substrate, such as the core substrate 10, supplied to the device 38, using colorants. The marking device thus provides, as an intermediate process result, the base substrate with an initial marking 1 formed thereon. The colorants can, in particular, contain one or more leuco dyes 12 or 13.

The laminating device 40 is designed to produce a laminate 8 from the base substrate 10 and at least one further planar substrate 11, in this example four overlay substrates. During lamination using the laminating device 40, the laminate 8 is formed from the substrates 10, 11 by applying pressure and/or heat, thus bonding the substrates 10, 11.

The energy source 41 for causing a locally selective energy input into the laminate 8 at the location of the initial marking 1 during or in the example of the 28 After the production of the laminate 8, the energy source can be, in particular, the laser 16. The type of laser processing for producing the target marking 15 from the initial marking 1 has already been explained in detail in various variants.

REFERENCE MARK LIST

1

Starting marker

2

Patterns within the initial marking

3

sub-area, dot, or subpixel

4

pixel or picture element

5

Macroscopic view of a comparison of two raster graphics

6

Microscopic view of a comparison of two raster graphics

7

2D representation of a color space with variant-dependent color space sections

8

laminate

9

Raster graphic of the initial marker, color component only

10

(First) core substrate, especially core film

11

Overlay substrate

12

colorless form of oxazine in spiro form

13

colored form of oxazine in spiro form

14

Switching from leuco dye

15

multicolored marking (target marking)

16

Laser

17

Laser radiation

18

Selective disintegration of dots

19

Hiding portions of the initial marker

20

blisters or knots

21

Laminate surface

22

Partially edited area of a dot

23

Color tones (correspond to grayscale levels in a grayscale image)

24

Microscopic view of CMYK color step image

25

macroscopic view CMYK color step image

26

Stacks of layers, especially foil packages

27

further layer (top layer)

28

second core substrate, especially core film

29

slightly darkened space due to increased black content

30

Whitened M-dot, subsequently completely darkened by blackening.

31

W-dot slightly darkened due to increased black content

32

by color tinting (cf. 12 ) lightened M-dot

33

Lightened Y-dot, subsequently darkened by blackening

34

Lightened C-dot, subsequently darkened by blackening

35

whitened Y-dot

36

Opening, window

37

(second) metal layer

38

Device for producing a document body comprising a multi-layer laminate with multi-colored marking inside the laminate

39

Marking device

40

Laminating device

41

Energy source, especially laser 16

42

Control device

C

cyan-colored area (dot)

M

magenta area (dot)

Y

yellow area (dot)

W

undefined, especially white or transparent, sub-area

D

Pixel diameter

d

Dot diameter

F

Compression forces during pre-lamination

x, y

Arrangement-dependent distances between neighboring dots of a pixel

y1, y2, y3

Machining depths for laser processing

REFERENCES

• [1] Baillet, Gilles et al. “Comparative photodegradation study between spiro[indolineoxazine] and spiro[indoline-pyran] derivatives in solution.” Journal of Photochemistry and Photobiology A-chemistry 70 (1993): 157-161 .

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions.

Cited patent literature

• DE 10 2022 209 198.1 [0087]

Cited non-patent literature

• Baillet, Gilles et al. “Comparative photodegradation study between spiro[indolineoxazine] and spiro[indoline-pyran] derivatives in solution.” Journal of Photochemistry and Photobiology A-chemistry 70 (1993): 157-161 [0162]

Claims (24)

A method for producing a document body comprising a multilayer laminate (8) and generating a multicolored, data-representing marker within the laminate (8), the method comprising: Providing or producing an initial marker (1) in or on an areal substrate, wherein the initial marker (1) has several colored sub-areas (3) such that the colors of at least two of the sub-areas (3) differ from one another; Producing the laminate (8) by laminating the substrate (10; 11) as the first laminate layer with at least one further areal substrate as each subsequent laminate layer such that the initial marker (1) is located at least partially within the produced laminate (8); inducing an energy input into the laminate (8) such that it acts locally selectively at the location of the initial marking (1), whereby the multicolored marking (15) representing the data is generated at least partially from the initial marking (1) by means of a locally selective color change of the initial marking (1) caused by the energy input into the initial marking (1). Procedure according to Claim 1 , wherein the energy input is at least partially achieved by means of a locally selective input of electromagnetic radiation using a sub-surface laser processing method, SSLE, into the initial marking (1) located inside the laminate (8). Procedure according to Claim 2 , wherein an ultrashort pulse laser (16) is used to effect the locally selective energy input into the initial marking (1) for the execution of the sub-surface laser processing method. Procedure according to Claim 2 or 3 , wherein a focal length of a laser (16) used to carry out the sub-surface laser processing method is adjusted depending on the location of the initial marking (1) or, in the case of its layer-by-layer construction, on the location of a selected sub-layer of the initial marking (1) such that a focal point corresponding to the focal length is located at or in the initial marking (1) or its selected sub-layer. A method according to any of the preceding claims, wherein: at least one of the colors is at least partially produced by colorants that are or are designed as a leuco-dye (12; 13) which, by the input of energy at the point of its action on the leuco-dye (12; 13), is switchable between - a colored and a differently colored state or - an opaque and an at least partially transparent state or - vice versa; and the locally selective color change of the initial marking caused by the input of energy into the initial marking (1) comprises at least a partial, locally selective switching of the leuco-dye (12:13). A method according to any of the preceding claims, further comprising: Performing a distortion correction with respect to a locally selective first energy input pattern provided as a target pattern for energy input before or during the application of the energy input according to a second energy input pattern resulting from the distortion correction; wherein, within the framework of the distortion correction, the second energy input pattern is obtained from the first energy input pattern depending on correction information that is or has been determined depending on a detected deviation of the actual shape of the produced laminate (8) from a target shape defined for the laminate (8). Method according to one of the preceding claims, wherein the initial marking (1) is provided or produced at least sectionally as a raster graphic (9) made up of pixels or line segments, wherein the raster graphic (9) has at least two different colors. Procedure according to Claim 7 , wherein the initial marking (1) is provided or produced as a raster graphic (9) of at least three colors with: pixels (4) as picture elements, wherein the pixels (4) are at least a subset of the pixels (4) each subpixel of all colors occurring in the raster graphic (9) from the set of colorants and optionally include a subpixel not colored by any of the colorants; and/or several groups of line segments, wherein the line segments of each group are adjacent and of different colors, and at least one of the groups includes line segments of all the colors occurring in the raster graphic (9) from the set of colorants and optionally a line not colored by any of the colorants. Procedure according to Claim 7 or 8 , wherein, within the framework of the raster graphic (9), a pixel variation or line variation is used to determine the tonal value for at least one of the colors of the raster graphic (9) in such a way that, when producing the multicolored marking for at least a subset of the pixels or line segments, the color change of the initial marking is carried out proportionally to the area by locally selective processing of the initial marking for this respective color depending on the tonal value to be represented. A method according to any of the preceding claims, wherein: the initial marking (1) is or is configured such that it contains at least one polymer material as a component which is carbonizable by radiation exposure; and the effecting of the locally selective energy input into the initial marking (1) comprises locally selective irradiation of the initial marking (1), by means of which locally selective carbonization of the polymer material in the initial marking (1) is effected. Procedure according to Claim 10 , wherein the irradiation is carried out with variable irradiation intensity and/or irradiation duration, so that the degree of carbonization at the respective point of impact of the irradiation in the polymer material is made variable with respect to the proportions of the colored marking formed by the irradiation in the sense of a tonal value determination. Method according to one of the preceding claims, wherein, for the production of the initial marking (1), the colorants were or are applied at least partially by printing on the base substrate (10; 11) and/or by applying one or more further substrates, each containing an associated colorant, as a respective partial layer of the initial marking (1) to the base substrate (10; 11). Method according to one of the preceding claims, wherein the base substrate (10; 11) contains a polymer material as a component or is entirely composed of it, and for the production of the initial marking (1) a polymerizing color is used as at least one of the colorants, which is selected such that it bonds to the base substrate (10; 11) by polymerization during lamination. Procedure according to Claim 13 , wherein the initial marking (1) is or is defined such that the area or space occupied by the colorants after the initial marking (1) has been produced constitutes at least 51%, in particular at least 71%, and in particular at least 91% of the area or space enclosed by the enveloping of the initial marking (1). Method according to one of the preceding claims, wherein the initial marking (1) is or is produced at least partially as a prefabricated stack of layers (26) consisting of several differently colored, each opaque or semi-transparent layers, of which at least one layer has one or more colored sub-areas (3) with leuco dye (12; 13). Procedure according to Claim 15 , wherein the prefabricated layer stack (26) is selected or is positioned relative to the base substrate (10; 11) before the joint lamination such that a projection of the layer stack (26) onto a virtual plane orthogonal to its stacking direction lies completely within a projection of the base substrate (10; 11) onto the same virtual plane. Procedure according to Claim 16 , wherein the prefabricated layer stack (26) is or becomes at least partially integrated into a cavity formed in the base substrate (10; 11). Method according to one of the preceding claims, wherein: a metal layer is applied to a surface of the laminate (8) before the multi-colored marking is produced; one or more openings are created in the metal layer in a locally selective manner; and through at least one of the created openings, the selective energy input into the laminate (8) at the location of the initial marking (1) is carried out, generating the multicolored marking representing the data from the initial marking (1) by means of the locally selective processing or removal of dye caused by the energy input. A method according to one of the preceding claims, wherein: at least one of the further substrates in the laminate (8) contains a polymer material in which local bubble formation can be caused by the locally selective energy input; and this energy input is caused in such a way that local bubble formation occurs in the polymer material of the at least one further substrate, which leads to a color change of the polymer material at a location of the energy input and thereby forms an opaque or semi-transparent locally selective masking of the initial marking (1), which contributes at least partially to the definition of the multicolored marking. A method according to one of the preceding claims, wherein one of the further substrates is formed as an optically variable layer (27) whose color and/or degree of transparency can be locally changed by the spatially selective energy input at the location of the action of the energy input on the optically variable layer (27); and the locally selective energy input is effected in such a way that at the respective location of the action of the energy input on the optically variable layer (27) such a local change of its color and/or degree of transparency is effected and thereby a locally selective masking of the initial marking (1) is formed, which contributes at least partially to the definition of the multicolored marking (15). Method according to one of the preceding claims, wherein: one of the further substrates is formed as a metal layer covering at least part of the initial marking (1); and by locally selective energy input, a local removal of the metal from the metal layer occurs, resulting in a locally selective exposure of a viewing area of the initial marking (1), which contributes at least part to the definition of the multicolored marking (15). Document body comprising a multilayer laminate (8) with data inscribed therein, wherein a multicolored marking (15) is formed inside the laminate (8) which represents the inscribed data, wherein the document body is obtainable by carrying out the method according to one of the preceding claims. Device (38) for producing a document body comprising a multilayer laminate (8) by generating a multicolored marking (15) representing data within the laminate (8), the device (38) comprising: a marking device (39) for providing or producing an initial marking (1) on an areal substrate (10; 11) using colorants, such that the initial marking (1) has several colored sub-areas (3) such that the colors of at least two of the sub-areas (3) differ from each other; a laminating device (40) for producing a laminate (8) from the substrate (10; 11) and at least one further areal substrate (11); an energy source (41) for effecting a locally selective energy input into the laminate (8) at the location of the initial marking (1) during or after the production of the laminate (8); and a control device (42) configured to cause the device (38) to use the method according to one of the following for the production of the document body with data inscribed therein. Claims 1 until 21 to execute. Device (38) according Claim 23 , wherein the marking device (39) is configured to provide or produce the initial marking (1) on the base substrate (10; 11) using the colorants, each of which is or is designed as a leuco-dye (12; 13), wherein the respective leuco-dye (12; 13) is switchable (14) between a colored and a differently colored or an opaque and an at least partially transparent state, or vice versa, by an energy input at the location of its action on the leuco-dye (12; 13).