DE102018119706B4 - Information carrier and method for its production - Google Patents

Abstract

Information carrier (10), comprising a substrate (12), in which a first pattern (22, 22a) composed of a plurality of pixels of the first type and pixels of the second type is inscribed, which when illuminated with coherent light of a predetermined illumination wavelength by interference of light components interacting with its pixels acts as a first hologram encoding a first image, each first type pixel carrying a first type diffraction grating (20, 20a) and each second type pixel carrying either no diffraction grating or carrying a second type diffraction grating which differs from differs from the diffraction grating of the first type (20, 20a) by the arrangement of its grating lines, wherein at least one second pattern ( 22b) is inscribed, the diffraction gratings of the first type (20a, 20b) belonging to the different patterns (22a, 22b). separate pixels of the first type in the arrangement of their grid lines and the individual patterns (22a, 22b) are arranged interlaced to form a super pattern (22*) on a surface that can be illuminated simultaneously, characterized in that the pixels of the first type are subdivided into several subtypes of pixels of the first type are whose diffraction gratings of the first type (20a, 20b) differ from one another in their diffraction efficiency.

Description

field of invention

The invention relates to an information carrier, comprising a substrate in which a first pattern composed of a plurality of pixels of the first type and pixels of the second type is inscribed acts as a first hologram encoding a first image, each pixel of the first type carrying a first type diffraction grating and each second type pixel carrying either no diffraction grating or a second type diffraction grating which differs from the first type diffraction grating in the arrangement of its grating lines , wherein at least one second pattern constructed analogously to the first pattern and acting as a second image coding, second hologram is inscribed in the substrate, the first-type diffraction gratings of the first-type pixels associated with the different patterns being in the arrangement differ in their grid lines and the individual patterns are arranged interlaced to form a super pattern on a surface that can be illuminated simultaneously.

The invention further relates to a method for producing such an information carrier.

State of the art

Generic information carriers are known from the WO 94/28444 A1 .

In classical holography, as is known, to put it simply, that interference pattern which results from the superimposition of a coherent light scattered on the object and a reference light corresponding to the illumination light is recorded as a representation of an object. If this recorded interference pattern is later illuminated again with a reconstruction light corresponding to the illumination light, an image of the object is thereby reconstructed. The special feature of holography lies in the preservation of the phase information, so that the reconstruction of a spatial object leads to a spatial image impression. However, this special feature does not come into its own in the holographic imaging of purely two-dimensional objects. As an alternative to the recording of a real interference pattern outlined above, it is also possible to calculate the interference pattern representing an object as a pattern composed of ordered pixels. A pattern recorded or calculated in this way, which represents an object in the sense explained, is referred to in the context of the present description as a “pattern acting as a hologram” or—in short—as a “hologram”. Holograms generated by means of the aforementioned calculation are often referred to as computer-generated holograms, CGH for short.

the EP 0 762 238 A1 discloses the possibility of overlaying patterns, which in themselves already act as a hologram, with further diffraction structures, in particular with an asymmetrical diffraction grating, in so-called superposition. This results in the effect that the image resulting from the reconstruction is predominantly in the (absolute) first order, in the +1. and -1. Order, however, appears with different intensities. The same publication also mentions the possibility of arranging different holograms, ie holograms representing different objects and superimposed with different diffraction gratings, next to one another in a so-called juxtaposition. If these juxtaposed structures are simultaneously illuminated with the reconstruction light during the reconstruction, images of the objects are reconstructed simultaneously, but in principle independently. Depending on the relative alignment of the diffraction gratings, the reconstructed images can overlap to different degrees or not at all. The publication mentioned discloses such structures as possible security features for banknotes, identification documents, etc.

From the DE 10 2004 003 984 A1 a holographic security element for documents is also known, which is constructed as a lattice field from a plurality of juxtaposed, differently shaped individual holograms with different lattice structures. When viewed from different angles, the different information encoded in each hologram becomes visible.

From the DE 10 2008 024 147 A1 an information carrier is known in which a pattern of microscopically fine, transparent and opaque zones is inscribed, with a surface lattice structure being formed in the transparent zones, the aspect ratio of which differs from the aspect ratio of a surface lattice structure which can be formed in the opaque zones , differs. This pattern of transparent and opaque zones corresponds to the imaging of a first item of information-generating, diffractive relief structure onto the pattern, with the possibility being disclosed for said relief structure of generating it as a CGH.

A disadvantage of all forms of pattern juxtaposition is the large amount of space required on the information carrier or the need for a corre corresponding large-area illuminating beam of light to make the encoded overall information visible.

The publications mentioned disclose only a few details on the details of the production of said superposition from a hologram and a diffraction grating. However, two variants appear obvious to the person skilled in the art: The arrangement of the hologram and diffraction grating in different layers of a complex layered substrate is conceivable. The pixels of the hologram can be realized in relief as a boundary surface between different materials and/or as a clouding or coloring of otherwise transparent or reflective substrate material. The disadvantage of this variant is the complex layer structure of the substrate, which leads to a highly complicated and time-consuming manufacturing process. Alternatively, it would be conceivable to calculate a highly complex combination pattern of hologram and diffraction grating, for example in the manner of an addition relief, and to write it into the substrate. However, such a highly complex combination pattern has very small pattern details, so that narrow limits are placed on a usually desired miniaturization of the resulting security features due to the limited resolution of conventional structuring methods.

From the EP 2 547 486 B1 a method and a device are known for inscribing spatially periodic structures, in particular line gratings, into a substrate by means of laser ablation. A so-called two-grating interferometer is used here, which is able to split a laser beam of a processing wavelength suitable for the respective substrate and cause it to interfere with itself, so that the substrate is illuminated with the resulting interference pattern in a very small area. The fluence of the illumination is at least in regions above a processing threshold of the substrate. The result is a structuring of the substrate in the illuminated area that corresponds to the interference pattern. With pulsed illumination and synchronized shifting of the illumination area, it is possible to structure a large substrate area pixel by pixel. It is possible to switch one of the gratings between two pulses, resulting in different interference patterns per pixel. The substrate can be almost any material, for example quartz, glass, metal, ceramic or the like. The processing wavelength is to be matched to the optical properties of the substrate in such a way that there is sufficient absorption for the desired material modification, in particular an ablation of the substrate material. In addition to ablation, other types of material modification, for example locally limited polymerisation or the like, are also possible.

task

It is the object of the present invention to further develop a generic information carrier in such a way that it is possible to encode a larger number of images of different objects in a very small space in an easily realizable manner.

Presentation of the invention

This object is achieved in connection with the features of the preamble of claim 1 in that the pixels of the first type are subdivided into a plurality of subtypes of pixels of the first type, the diffraction gratings of the first type of which differ from one another in their diffraction efficiency.

1. a) Bereitstellen eines Substrates aus einem Licht einer vorgegebenen Beleuchtungswellenlänge transmittierenden oder reflektierenden und Licht einer Bearbeitungswellenlänge absorbierenden Substratmaterial,
2. b) Bereitstellen eines aus einer Mehrzahl von virtuellen Pixeln erster und zweiter Art zusammengesetzten, virtuellen Musters, welches ein ein Bild codierendes Hologramm repräsentiert,
3. c) pixelweise selektives, dem virtuellen Muster derart entsprechendes Bestrahlen des Substrates mit Lichtpulsen der Bearbeitungswellenlänge und einer wenigstens bereichsweise oberhalb einer Bearbeitungsschwelle des Substratmaterials liegenden Energiedichte, dass an jeder einem virtuellen Pixel erster Art entsprechenden Position des Substrates zur Schaffung eines Pixels erster Art ein Beugungsgitter erster Art eingeschrieben wird.

Such an information carrier can be produced using a method according to claim 7, namely using a method comprising the steps:

1. a) providing a substrate made of a substrate material that transmits or reflects light of a predetermined illumination wavelength and absorbs light of a processing wavelength,
2. b) providing a virtual pattern composed of a plurality of virtual pixels of the first and second type, which represents a hologram encoding an image,
3. c) pixel-by-pixel selective irradiation of the substrate corresponding to the virtual pattern with light pulses of the processing wavelength and an energy density at least in some areas above a processing threshold of the substrate material that at each position of the substrate corresponding to a virtual pixel of the first type to create a pixel of the first type a diffraction grating of the first kind is enrolled.

Preferred embodiments are subject of the dependent claims.

As is known in principle, it is also provided within the scope of the present invention to first differentiate in a hologram the “active” pixels, referred to here as pixels of the first type, from the “inactive” pixels, referred to here as pixels of the second type. In this context, "active" means that the hologram-typical interference is caused by the interaction of the (reflected or transmitted) light components emanating from these "active" pixels. From the "inactive" Pixels, on the other hand, do not emit any light components that contribute to the interference typical of holograms. Rather, the "inactive" pixels serve to ensure the necessary spacing between the "active" pixels for interference. In principle, such a distinction can be made in the case of any hologram constructed pixel by pixel. It is further provided within the scope of the invention that the “active” pixels are created by inscribing a diffraction grating of the first type at the corresponding position on the substrate. The “inactive” pixels, on the other hand, are created by not writing such a first-type diffraction grating at the substrate position corresponding to them. Particularly preferably, these positions can simply be left unprocessed. However, any other processing is also conceivable, with the exception of creating a diffraction grating of the first type, ie a diffraction grating with the same line spacing and the same angular orientation of its grating lines.

The diffraction grating of the first type diffracts the light components emitted by the pixels of the first type primarily not into the zero order, but into a higher diffraction order, in particular into the first diffraction order (relative to the diffraction grating). Here they come to the desired interfering interaction. Since the pixels of the second type have no or a different diffraction grating, light components emitted by them are emitted (transmitted or reflected) in other (spatial) directions and therefore cannot disturb the reconstruction of the image encoded in the hologram.

In other words, the information carrier does not consist of the superposition of a hologram and a diffraction grating; Rather, the hologram itself consists (only) of areas with a first diffraction grating (“active” pixels, pixels of the first type) and areas without a first type diffraction grating (“inactive” pixels, pixels of the second type).

Such a pattern acting as a hologram can ideally be produced with a two-grating interferometer which, as explained at the outset and known from the prior art, is able to provide a substrate with miniaturized diffraction gratings pixel by pixel.

The advantage of this approach lies in the possibility of inscribing the pattern acting as a hologram directly, pixel by pixel, into the substrate. As a result, a complicated layer structure of the substrate, as in the case of a spatial superimposition of a diffraction grating, is not required. In addition, the structures to be written into the individual pixels are of a comparatively simple nature, namely in particular simple line grids. The smallest characteristic variable that needs to be resolved is the line spacing. Even finer details, such as those that occur when a hologram and a line grating are superimposed in a common plane and can quickly overwhelm structuring processes, do not occur. The information carrier can therefore be produced quickly, inexpensively and with extreme miniaturization, which is of great importance in particular for hidden security features on any (commercial) products where a need for security marking is seen.

In order to solve the problem, namely to ensure that it is possible in an easily achievable manner to encode images of different objects in a very small space and to make them visible simultaneously in different spatial regions during the reconstruction, it is first provided that at least one second pattern which is constructed analogously to the first pattern and acts as a second hologram encoding a second image, the diffraction gratings of the first type of the pixels of the first type belonging to the various patterns differing in the arrangement of their grating lines. Like the first pattern, the second pattern consists of a collection of pixels of the first type, i. H. of pixels with a first-type diffraction grating, and second-type pixels, i. H. of pixels that do not carry a diffraction grating of the first kind (related to the first pattern). The patterns differ at least in the arrangement of the grating lines of their respective first-type diffraction grating. The difference can—preferably—consist in the angular orientation of the grating lines. Alternatively or additionally, the patterns can differ in terms of the line spacing of their diffraction gratings of the first type. Both measures ensure that the respective coded image is reconstructed in other spatial areas. It is of course possible and even preferably provided that the patterns also differ in the respectively encoded images. Of course, it is also possible to inscribe more than just two different patterns of the structure according to the invention in the substrate.

With regard to the spatial arrangement of the different patterns on the substrate, it is provided that the individual patterns are arranged together to form a super pattern on a surface that can be illuminated simultaneously. The super pattern is composed of super pixels, which in turn are composed of sub-pixels, each super pixel containing as sub-pixels those patterns of the pixels that are arranged in their own pattern at that position which corresponds to the position of the super pixel in the super pattern. The following simple example is given for explanation: Four different patterns, each made up of 32 x 32 pixels, are to be created in the frame men of the entanglement variant are positioned on the substrate. This is done by writing a super pattern, also of 32×32 super pixels. Each super pixel is made up of four sub-pixels, with each sub-pixel corresponding to a pixel of one of the four different patterns. In particular, the super-pixel arranged in the “upper left” super pattern is composed of the four pixels each arranged in its own “upper left” pattern as its sub-pixels. The same applies to each additional super pixel of the super pattern.

The relative arrangement of the pixels belonging to the individual patterns as subpixels within a superpixel is preferably identical for all superpixels of the superpattern. In the context of the example above, this could mean that within each super-pixel, the corresponding pixel of the first pattern occupies the position of the “upper right” sub-pixel, the pixel of the second pattern occupies the position of the “lower right” sub-pixel, and so on. In this way, there are no shifts in the distances between the pixels assigned to a pattern in each case.

In the example above, the superpattern is composed entirely of interleaved holograms. i.e. each sub-pixel corresponds to the pixel of a pattern that itself acts as a hologram. However, this is not mandatory in the context of the entanglement. As an alternative, it is also possible not to cover one or more subpixels in each superpixel with pixels of a pattern that itself acts as a hologram; instead, it can be provided that each superpixel contains as one of its subpixels a pixel of a third image extending over the surface of the superpattern. These particular sub-pixels are not part of a hologram, but direct pixels of a non-hologram encoded image. This image, referred to here as the third image, is directly visible with any lighting - depending on the nature of the substrate in reflection and/or in transmission, in particular no coherent lighting is necessary. In other words, when viewing the information carrier, the direct, third image will always be visible, while the images encoded as holograms only become visible under special illumination with coherent light of a suitable illumination wavelength. In the event that the sub-pixels representing the direct, third image are realized as essentially unprocessed substrate areas, the third image will become visible when observed essentially perpendicularly. It is known to generate directly observable images using diffraction gratings, so that the respective color impression changes under white light when the viewing angle changes. Such images can be easily combined with images according to the invention.

Those skilled in the art will recognize that the term illumination wavelength is not to be understood in the context of the present invention as a limiting reference to a possibly necessary (but actually not necessary) use of monochromatic light of a specific wavelength. The explained effect of the holograms will basically occur when illuminated with any light colour. The deflection of the light that occurs at the diffraction gratings is, of course, dependent on the wavelength. If the actual illumination wavelength deviates too much from the "optimal" illumination wavelength on which the calculation of the CGH is based, this may result in distances of the reconstructed images from the zeroth order that are too large or too small for actual observability in the context of a specific experimental setup. However, knowledge of the details of the CGH calculation and its production on the one hand and the experimental setup of the reconstruction apparatus on the other hand will enable the person skilled in the art to determine the spectrum of suitable illumination wavelengths without difficulty.

Such computer-generated holograms are "black/white" encoded. In other words, the pixels of the first type on the one hand and the pixels of the second type on the other hand are configured identically to one another. This limits the information content of the hologram. A hologram according to the invention is therefore in the form of a “grayscale” CGH. Thus, according to the invention, it is provided that the pixels of the first type are subdivided into a number of subtypes of pixels of the first type, the diffraction gratings of the first type of which differ from one another in terms of their diffraction efficiency. Structurally, different diffraction efficiencies can be realized by different groove depths of diffraction gratings that are otherwise the same, in particular with regard to line spacing and angular alignment. The different subtypes of the "active" pixels of the first type thus contribute to the reconstruction of the image to different extents. Light components emanating from the "inactive" pixels of the second type still do not contribute to the image reconstruction. Even if in the further description, for reasons of easier understanding, mostly only embodiments without efficiency staggering within the pixels of the first type are discussed, those skilled in the art should keep in mind that an embodiment with staggered diffraction-efficient pixels of the first type is always possible.

Further features and advantages of the invention result from the following specific description and the drawings.

character list

• 1: eine schematische Darstellung des Verlaufs eines erfindungsgemäßen Verfahrens zur Herstellung eines erfindungsgemäßen Informationsträgers,
• 2: eine bereichsweise Schnittdarstellung eines resultierenden, erfindungsgemäßen Informationsträgers,
• 3: eine schematische Darstellung des Rekonstruktionsprozesses unter Verwendung des Informationsträgers der 1 und 2,
• 4: eine stark vereinfachte Darstellung eines erfindungsgemäßen Informationsträgers mit mehreren, zu einem Supermuster miteinander verschränkten Mustern.

Show it:

• 1 : a schematic representation of the course of a method according to the invention for the production of an information carrier according to the invention,
• 2 : a sectional view of a resulting information carrier according to the invention,
• 3 : a schematic representation of the reconstruction process using the information carrier 1 and 2 ,
• 4 : a greatly simplified representation of an information carrier according to the invention with a plurality of patterns interlaced to form a super pattern.

Description of Preferred Embodiments

The same reference numbers in the figures indicate the same or analogous elements.

1 shows a rough schematic of the sequence of a method according to the invention for the production of an in 2 The information carrier 10 according to the invention, shown in part, consists of a substrate 12. The substrate 12 can be a plate made of reflective or transparent material, for example glass, quartz, metal, plastic, a polymer precursor or the like. act. The optical properties mentioned are to be understood in relation to those wavelengths which are to be used for the viewing or the reconstruction of the image - referred to here generally as "the reconstruction wavelength" or "the viewing wavelength".

In the case shown, the information carrier 10 should contain the information of the links in 1 Motif shown 14, the logo of the applicant wear. For this purpose, a CGH 16 is calculated as a virtual pattern of “black” and “white” pixels—generally: virtual pixels of the first and second type—from the motif 14 using algorithms that are fundamentally known to those skilled in the art. The CGH 16 is then used as the basis for controlling a two-grating interferometer 18, which is known in principle to a person skilled in the art. In this case, a laser beam is split up and superimposed in an interfering manner, with the surface of the substrate 12 being positioned close to the focal plane of the superimposed partial laser beams. If the substrate material, laser wavelength and laser intensity are suitably coordinated, a diffraction grating can be written into the substrate at the instantaneous irradiation point. In particular, the wavelength of the laser—the processing wavelength—must be selected in a range in which the substrate 12 shows sufficiently high absorption such that a material modification threshold of the substrate material, in particular an ablation threshold, is exceeded at the given laser intensity. The laser is operated in pulsed mode. With each pulse, a substrate surface with a lateral extent of a few micrometers up to several tens of micrometers can be processed, ie provided with a diffraction grating. By pulse-synchronously shifting the laser beam relative to the substrate 12, a large substrate area can be scanned in this way, with a diffraction grating 20 actually being written into the substrate 12 at selected positions and other substrate positions left unprocessed (or written with a different type of diffraction pattern). Each such processing position corresponds to a pixel of the real pattern 22 written in the substrate 12.

According to the invention, the substrate processing process is controlled according to the pattern of the (virtual) CGH 16. For example, those positions on the substrate 12 that correspond to "white" pixels in the virtual pattern 16 can be covered with a first-type diffraction grating, while those positions on the Substrate 12 corresponding to "black" pixels in virtual pattern 16 remain unprocessed. The real hologram 22 is therefore composed of pixels of the first and second type, which differ from one another in that the pixels of the first type carry a diffraction grating of the first type, while the pixels of the second type do not.

2 Figure 1 shows a resulting information carrier 10 in a sectional view spanning an area of slightly more than three pixels. The two outer pixels shown in full are first type pixels, ie they carry a first type grating 20. The central pixel shown is a second type pixel, ie it does not carry a first type grating 20. In the illustrated embodiment, the second type pixels exist in particular from unprocessed substrate.

With illumination of the information carrier 10 - in 2 Illumination or reconstruction light 24 incident on a reflective information carrier 10 in the normal direction is shown - light components incident on a pixel of the first type are primarily diffracted into the first diffraction order (+1st and -1st order), while those incident on a pixel of the second type Light components are essentially reflected back (zero order). Under the viewing angle associated with the first diffraction order, the light components originating from the pixels of the first type are superimposed, while the pixels of the second type act as "dark" spacers at this viewing angle. Under this viewing angle, ie in the first diffraction order, the image encoded in the pattern is reconstructed in the same way as would be the case in the zeroth order with a normal hologram made up of true black and white pixels.

3 shows the reconstruction process in a more global representation. The information carrier 10 is illuminated with the coherent reconstruction light 24 . During the reconstruction, a real double image 26 of the motif 14 holographically encoded in the pattern 22 is created in each diffraction order (relative to the diffraction grating of the pixels of the first type). It should be noted that the two individual images of said double image are point-symmetrical to one another. The deflection experienced by the double image relative to the zeroth order of diffraction, ie to directly reflected reconstruction light 24, depends on the angular orientation and on the line spacing of the diffraction grating 20 of the first-type pixels for a given illumination angle.

Even with this simplest embodiment of the invention, there is the advantage that the reconstructed image 26 is not superimposed with the directly reflected light of the zeroth order and can therefore be clearly recognized in a predictable angle range.

The particular strength of the present invention, however, lies in the possibility of storing several images that can be reconstructed simultaneously on a limited area. Two variants are in the 4a and 4b shown, which are intended to illustrate the principle in an extremely simplified representation.

According to 4a two motifs 14a, 14b are to be deposited on the information carrier 10 in holographically encoded form. For this purpose, the corresponding (virtual) CGH are calculated and corresponding patterns 22a, 22b are written into the substrate 12. FIG. Through a reproductive process according to 3 the images 26a, 26b can be generated with separate illumination of the patterns 22a, 22b. Shown are the double images of the +1. and -1. Order grouping around the zeroth order shown as the central point, as indicated by corresponding ordinal numbers in the figures. The positions of the double images in the reconstructed image 26a relative to the associated zeroth order differ from the corresponding positions in the reconstructed image 26b, since the diffraction gratings of the first type 20a in the pattern 22a differ from the diffraction gratings of the first type 20b in the pattern 22b with regard to the angular position of their grating lines.

4b 12 shows how the patterns 22a, 22b are written into the substrate 12 interlaced with one another to form a superpattern 22*. Each super pixel of the super pattern 22* is denoted by row and column with Roman numerals (rows) and capital Latin letters (columns). In the embodiment shown, each super pixel consists of four sub-pixels. The sub-pixel arranged at the top left of each super-pixel corresponds to the corresponding pixel of the pattern 22a; the sub-pixel located at the bottom right of each super-pixel corresponds to the corresponding pixel of pattern 22b. Thus, the super-pixel A/IV contains as its upper-left sub-pixel the pixel a/4 of the pattern 22a and as its lower-right sub-pixel the pixel a/4 of the pattern 22b. In the embodiment shown, only two of its sub-pixels, namely the sub-pixel arranged at the top left and the sub-pixel at the bottom right, are assigned to one of the patterns 22a, 22b acting as holograms in each superpixel. In contrast, the two remaining subpixels, namely the top right subpixel and the bottom left subpixel, are not assigned to a pattern acting as a hologram. It is easily possible to also assign these subpixels accordingly. Alternatively, it is conceivable to use these subpixels to realize a real, ie not holographically encoded, image extending over the surface of the super pattern 22*, in particular an image with coloring dependent on the viewing angle.

If none of these options are used, as in 4b shown, the simultaneous illumination of the entire super pattern 22* for the simultaneous reconstruction of the images 26a, 26b, these being shown in different spatial regions due to the different alignment of their respective diffraction gratings of the first type 20a, 20b.

Of course, the embodiments discussed in the specific description and shown in the figures only represent illustrative exemplary embodiments of the present invention. In particular, it should be pointed out that the lines shown in the figures for the optical separation of the superpixels, pixels or subpixels normally have no correspondence in reality.

Reference List

10

information carrier

12

substrate

14, 14a, 14b

motive

16

virtual pattern, CGH

18

Two-grating interferometer

20, 20a, 20b

Diffraction grating of the first kind

22, 22a, 22b

Pattern

22*

super pattern

24

reconstruction light, illumination light

26, 26a, 26b

reconstructed image

Claims (9)

Information carrier (10), comprising a substrate (12), in which a first pattern (22, 22a) composed of a plurality of pixels of the first type and pixels of the second type is inscribed, which when illuminated with coherent light of a predetermined illumination wavelength by interference of light components interacting with its pixels acts as a first hologram encoding a first image, each first type pixel carrying a first type diffraction grating (20, 20a) and each second type pixel carrying either no diffraction grating or carrying a second type diffraction grating which differs from differs from the diffraction grating of the first type (20, 20a) by the arrangement of its grating lines, wherein at least one second pattern ( 22b) is inscribed, the diffraction gratings of the first type (20a, 20b) of the various patterns (22a, 22b) being drawn corresponding pixels of the first type differ in the arrangement of their grid lines and the individual patterns (22a, 22b) are arranged interlaced with one another to form a super pattern (22*) on a surface that can be illuminated simultaneously, characterized in that the pixels of the first type are divided into several subtypes of pixels of the first type are subdivided, the diffraction gratings of the first type (20a, 20b) differ from one another in their diffraction efficiency. Information carrier (10) after claim 1 , characterized in that the diffraction gratings of the first type (20a, 20b) of the pixels of the first type belonging to the different patterns (22a, 22b) differ in the angular orientation of their grating lines. Information carrier (10) according to one of the preceding claims, characterized in that the diffraction gratings of the first type (20a, 20b) of the pixels of the first type associated with the different patterns (22a, 22b) differ in the line spacing of their grating lines. Information carrier (10) according to one of the preceding claims, characterized in that the super pattern (22*) is composed of super pixels, which in turn are composed of sub-pixels, each super pixel containing as sub-pixels those pixels of the pattern (22a, 22b) which in are arranged in their respective pattern (22a, 22b) at that position which corresponds to the position of the super pixel in the super pattern (22*). Information carrier (10) after claim 4 , characterized in that the relative arrangement of the pixels belonging to the individual patterns (22a, 22b) as sub-pixels within a super-pixel is identical for all super-pixels of the super-pattern (22*). Information carrier (10) according to one of the preceding claims, characterized in that each superpixel contains as one of its subpixels a pixel of a third image extending over the surface of the superpattern (22*). Method for producing an information carrier (10) according to one of the preceding claims, comprising the steps: a) providing a substrate (12) made of a substrate material that transmits or reflects light of a predetermined illumination wavelength and absorbs light of a processing wavelength, b) providing a virtual pattern (16) composed of a plurality of virtual pixels of the first and second type, which represents a hologram encoding an image, c) pixel-by-pixel selective irradiation of the substrate (12), corresponding to the virtual pattern (16), with light pulses of the processing wavelength and an energy density at least in some areas above a processing threshold of the substrate material, such that at each position of the substrate (12) corresponding to a virtual pixel of the first type writing a first type diffraction grating (20) to create a first type pixel. procedure after claim 7 , characterized in that the pixels of the second type remain unprocessed. Procedure according to one of Claims 7 until 8th , characterized in that the substrate (12) is irradiated with a pulsed laser beam brought to interfering superimposition with itself by means of a two-grating interferometer (18), so that the substrate positions intended for the creation of pixels of the first type are successively line grating-like intensity-modulated irradiation pattern are irradiated.

Images