WO2023148213A1

WO2023148213A1 - Copy carrier arrangement and method for producing a hologram

Info

Publication number: WO2023148213A1
Application number: PCT/EP2023/052433
Authority: WO
Inventors: Stefan Schwedat; Nadin Brünner; Alexander Jakubzick
Original assignee: Carl Zeiss Jena Gmbh
Priority date: 2022-02-02
Filing date: 2023-02-01
Publication date: 2023-08-10
Also published as: DE102022102469A1

Abstract

Disclosed is a copy carrier arrangement which has a copy carrier, which comprises a photosensitive material, and a black cover (20) arranged on at least one side of the copy carrier (13), which comprises light absorbing carbon black particles and carrier material. A difference in refractive index between the copy carrier (13) and the carrier material at an interface between the black cover (20) and the copy carrier (13) is less than 0.2.

Description

Copy carrier arrangement and method for producing a hologram

The present application relates to copy carrier arrangements for producing holograms and methods for producing holograms using such copy carriers.

Modern micro-optical processes allow complex tasks such as imaging or monitoring of a specific environment, e.g. B. by means of holographic-optical elements (HOE) to be integrated inconspicuously or almost invisibly in large-format glass surfaces. Examples of applications are all types of transparent displays (e.g. in shop windows, refrigeration units, side or front windows of motor vehicles), lighting applications such as information and warning signals in any glass surface (e.g. design glazing of buildings), or light-sensitive detection systems, for example for interior surveillance (eye tracking). in vehicles and presence status of people indoors). In order to manufacture the required holographic-optical elements, it is important to manufacture them in a way that enables series production.

One possibility for copying holograms is to attach a so-called master hologram to or on an optically transparent cylindrical roller or an optically transparent hologram carrier. For copying, it is also necessary to attach unexposed material suitable for holography to or on the hologram carrier. This unexposed material suitable for holography, possibly together with other components such as carriers, is referred to below as the copy carrier.

The hologram is copied by illuminating the master hologram with the light required for the reconstruction of the master hologram, the reference beam. The copy carrier and the master hologram must not have any relative speed to one another in the area to be exposed. At the same time, the reference beam illuminates the previously unexposed material of the copy carrier, into which the master hologram is to be copied. An interference field is thus created in the copy carrier, which is created by the reference beam and the reconstructed optical function of the master hologram, ie light which is diffracted by the master hologram according to its function and which interferes with the reference beam. This interference field is ideally identical to the Microstructure in the master hologram, so that the structure of the master hologram is exposed in the previously unexposed material of the copy carrier.

In reality, with this procedure, there are additional optical transitions and interfaces due to the unavoidable differences in refractive index between the individual layers of the copy structure. These can lead to reflections, which in turn generate additional interference fields in the copy carrier. The most critical transitions with the strongest reflections are the transitions between the optically transparent materials, e.g. the copy carrier or the master hologram and the air.

In this regard, it is known to provide interfaces, in particular with air, with blackening, i.e. light-absorbing material, in order to absorb light. Such blackenings are known from EP 3 772 671 A1 or EP 2 801 867 A1. However, for example, a boundary surface with such a blackening can also lead to reflections.

It is therefore an object of the present application to propose possible improvements here.

This object is achieved by a copy carrier arrangement according to claim 1 or 9 and a method for producing a hologram according to claim 22. The dependent claims define further embodiments and a device with such a copy carrier arrangement.

According to a first aspect, a copy carrier arrangement is provided, comprising: a copy carrier, which comprises a photosensitive material, and a black cover which is arranged on at least one side of the copy carrier and which comprises light-absorbing carbon black particles and carrier material, with a refractive index difference between the copy carrier and the carrier material at an interface between the black cover and the copy carrier is less than 0.2.

In the context of the present application, a black cover means an absorbent covering of a surface. A copy medium is an entity into which a hologram is to be copied by exposure. Such a small difference in refractive index means that reflections at the interface are at least largely suppressed. By using soot particles, high absorption can be achieved, especially over a wide range of wavelengths. The difference in refractive index is preferably less than 0.02, preferably less than 0.01, in order to further suppress reflections.

"At least one side" means that the black cover can also extend over two or more sides of the copy carrier arrangement. In addition, in a system described further below, it can also extend over one or more sides of a master hologram and possibly a carrier.

A degree of reflection of the black cover is preferably less than 0.05%.

The carrier material can comprise a matrix in which the carbon black particles are arranged, for example made of polymer material.

The interface can be a surface of the matrix that faces the copy substrate. In this case, the refractive index difference mentioned above is therefore a refractive index difference between the material of the matrix and the copy support.

The substrate may include an adhesive film, wherein the interface is a surface of the adhesive film that faces the copy substrate. In this case, the refractive index difference mentioned above is thus a refractive index difference between the material of the adhesive film and the copy support. The black cover can be detachably connected to the copy carrier by the adhesive film.

A bond strength of the adhesive film is preferably less than 60 cN/cm. Due to such a low adhesive strength, the black cover can be removed comparatively easily after exposure.

The copy substrate may comprise a photopolymer placed on a substrate sheet.

The interface can be a surface of the photopolymer that faces the black cover. In this case, the refractive index difference mentioned above is thus a refractive index difference between the photopolymer and the black cover (e.g. the above matrix or the adhesive film). The copy substrate may have a cover sheet on the photopolymer, with the interface being a surface of the cover sheet that faces the black cover. In this case, the refractive index difference mentioned above is therefore a refractive index difference between the cover film and the black cover (e.g. the above matrix or the adhesive film).

The carbon black particles can be less than 500 nm in size, not structurally reduced and/or have a BET surface area according to ASTM D 6556 of greater than 200 m ² /g. With such soot particles, low reflection and high absorption of light can be achieved.

According to a second, alternative aspect, instead of or in addition to the soot particle(s) described above, graphene particles and/or nanotubes are used. Otherwise, the second aspect corresponds to the first aspect described above, i.e. apart from the use of graphene particles or nanotubes instead of the soot particles or in addition to the soot particles, the copy carrier arrangements of the second aspect are identical to those of the first aspect.

Graphene is a carbon modification consisting of one or more 2D layers of six-carbon rings. In the case of nanotubes, graphene layers are essentially formed into a tube, the diameter of which is typically less than 100 nm.

These types of particles (graphene or nanotubes) can be provided as a slurry in which the particles are in a solvent. This can be chosen to match the other materials of the copy carrier assembly, for this purpose an original solvent can also be replaced by a more suitable one. For this purpose, a solvent can be drawn off in a heating bath under vacuum and then another solvent can be added. This can also be done in several steps.

In addition, a device for producing holograms is provided, comprising: a master hologram, and a copy carrier arrangement arranged on the master hologram, as explained above.

The black cover can cover a side of the copy carrier arrangement that faces away from the master hologram and at least one side surface of the copy carrier arrangement and of the master hologram, optionally also other surfaces of the device. The The device can then have a light source, with a structure of the master hologram being exposed in the photosensitive material when illuminated by the light source.

According to another aspect, there is provided a method of making a hologram, comprising:

arranging a copy carrier on a master hologram,

placing a black cover on at least one surface of the copy substrate to form a copy substrate assembly as described above, and

Exposing the copy carrier to an interference pattern generated by means of the master hologram.

Such a method can be used to produce holograms while suppressing disruptive reflections.

The invention is explained in more detail below with reference to the accompanying drawings based on preferred exemplary embodiments. Show it:

FIG. 1 shows a schematic diagram of an apparatus for producing holograms according to an embodiment.

Figure 2 is a schematic diagram of a black cover copy carrier according to one embodiment.

Figures 3A to 3C are schematic diagrams of copy media with black covers according to various embodiments.

Figure 4 is a schematic diagram of a black cover according to some embodiments.

FIG. 5 shows a flowchart to illustrate a method according to an embodiment. Exemplary embodiments are explained in detail below. These embodiments are provided for illustration only and are not to be construed as limiting. Features of different exemplary embodiments can be combined with one another unless otherwise stated. Variations, modifications and details that are described for one of the exemplary embodiments can also be applied to other exemplary embodiments and are therefore not explained repeatedly.

FIG. 1 shows a schematic diagram of an apparatus 10 for producing holograms according to an exemplary embodiment. The device 10 serves to transfer a structure of a master hologram 12 into a copy carrier 13, which contains an initially unexposed material suitable for holography. The copy carrier 13 is arranged on the master hologram 12 for this purpose. For this purpose, the master hologram 12 is in turn arranged on an optically transparent carrier 11 . Instead of the illustrated optically transparent carrier 11, an optically transparent cylindrical roller can also be used, as explained above. Other carrier forms can also be used, for example optical free forms with a freely designed surface. The radii of curvature are preferably greater than 75 cm, preferably greater than 1 m. Such carriers can have a size of more than 1m ² , for example 2m×1m. In the case of such optical free forms, a polymer film material with a thickness of less than 250 μm and a modulus of elasticity of less than 3000 MPa is preferably used as the material for the copy carrier, which can be adapted to the corresponding free form.

In order to write the structure of the master hologram 12 into the copy carrier 13, the master hologram 12 and the copy carrier 13 are illuminated with light 16 from a coherent light source 15. In terms of wavelength, this light corresponds to the corresponding reconstruction wavelength of the master hologram 12. Several structures for different wavelengths can also be written by corresponding multiple exposures with light 16 of different wavelengths. Part of the light 16 enters the copy carrier 13 directly and serves as reference light. Another part of the light 16 is diffracted by the structures of the master hologram 12 and interferes with the reference light in the copy carrier 13 . The interference pattern that is produced in this way corresponds to the structure of the master hologram 12 to be copied. This structure is then exposed into the copy carrier 13 and the master hologram 12 is duplicated. After the copying process, the copy substrate 13 is then removed and the next, still unexposed copy substrate can be processed. This copying process is known per se and is therefore not explained further. Undesirable reflections can occur at the boundary surfaces of the structure made up of carrier 11 , master hologram 12 and copy carrier 13 to the environment (for example air), which can result in additional interference that falsifies the interference pattern occurring in the copy carrier 13 . In order to at least significantly reduce this effect, the device 10 has black covers 14A, 14B and 14C which cover corresponding areas. In this case, the black cover 14A is particularly important, since the light 16 falls directly on the boundary surface of the copy carrier 13 to the environment and strong reflections can therefore occur here without the black cover 14A. The black covers 14B, 14C can avoid further reflections.

As will be explained in more detail below, the black covers 14A, 14B, 14C, referred to collectively as black covers 14, have at least one light-absorbing material in the form of soot particles and a carrier material for the light-absorbing material. The support material has approximately the same refractive index as the component it covers at the respective interface. For example, the base material of the black cover 14A has approximately the same refractive index as the copy base 13 at the interface. Approximately the same refractive index means that the refractive index difference is less than 0.2, preferably less than 0.02 and particularly preferably less than 0.01. Reflections can be largely avoided by such small differences in the refractive index.

According to the Fresnel equation for perpendicular incidence of light, the reflection R is:

where n1 and n2 are the refractive indices of the materials at the interface. For example, if the refractive index of the copy carrier at the interface is 1.48 (e.g. triacetate film) and the carrier material of the black cover at the interface is 1.51 (e.g. an acrylate), the result is a refractive index difference of 0.03 and a reflection R of approx. 0. 01% Depending on the design of the black cover, the total degree of reflection of the black cover can result from the absorption of the soot particles used or their remaining degree of reflection and the reflection at the interface. For example, with Orion Special Black 4 Powder as a soot particle with a blackness value of 244 (according to DIN 55979), the total reflection of the black cover can be reduced to 0.055%. Subtracting the Fresnel reflection of 0.01% as an example value, this results in a purely formal reflectivity for the black pigment used itself of approx. 0.045% in the carrier material. The soot particles preferably have small particle sizes of less than 500 nm, preferably less than 250 nm, particularly preferably less than 100 nm, in particular less than 20 nm. The size here refers to the longest diameter (e.g. in the longitudinal direction in the case of a rod-shaped structure). The particles preferably have rod-like structures, thread-like structures, thread-like coiled structures, thread-like coiled and branched structures or mixed structures thereof. Such particles with a comparatively complex structure generally have a lower reflection than compact particles with a simple spherical geometry, cylinder geometry, cube geometry or platelet geometry. The latter particles with a simple geometry are collectively referred to as structure-reduced. Particles that are not structurally reduced are preferably used. The particles preferably have a BET (NSA) surface area according to ASTM D 6556 of greater than 200 m ² /g. In general, structurally reduced particles have a higher reflection and particles with a pronounced fine structure (larger BET surfaces) have a lower reflection, even if the latter are sometimes more difficult to incorporate into a carrier material, which is why a compromise between the degree of reflection and processability has to be chosen in some exemplary embodiments .

Examples of suitable carbon blacks are carbon black—Orion Engineered Carbons, gas black, furnace black, acetylene black, thermal black or lamp black. The density of the soot particles is so high that in a wavelength range of at least the light 16 used, preferably in a wavelength range of 400-800 nm, there is a degree of reflection below 0.1%, so that less than 0.1% of the light impinging on the interface is reflected.

In particular, combinations of copy carrier 13 and black cover 14 are provided in exemplary embodiments. Such a combination is also referred to as a copy carrier arrangement in the context of this application. Corresponding embodiment examples will now be explained.

Figure 2 shows a general diagram of a copy substrate assembly according to one embodiment. The copy carrier arrangement of FIG. 2 has the copy carrier 13 already discussed and a black cover 20 arranged on the copy carrier 13 . While the black cover 20 is only arranged on one side of the copy carrier 13 in FIG. Various configurations of the copy substrate 13 as well as the black cover 20 will now be explained with reference to Figures 3A to 3C and four.

In the exemplary embodiment in FIG. 3A, the copy carrier 13 is formed by a photopolymer 31 arranged on a carrier film 30 . The photopolymer 31 forms the initially unexposed, light-sensitive layer mentioned above, into which the structure of the master hologram is written. The carrier film 30 serves as a carrier for the photopolymer 31. Conventional materials used in the production of holograms can be used as materials for the carrier film 30 and the photopolymer 31.

In this case, the black cover 20 is arranged on the photopolymer 31 . The black cover 20 has the soot particles described embedded in a matrix. An example is shown in FIG.

Figure 4 shows it schematically soot particles 42 in a matrix 41, d. H. surrounding material, to form a black cover 40. The black cover 40 is an example of the black cover 20 of Figure 3A. The density of the particles 41 is shown only very schematically in FIG. 4 and is significantly higher in actual exemplary embodiments in order to achieve the desired absorption properties. Common thermoplastic materials, in particular those processed as a film, can be used as the material for the matrix 41 . Examples for this are . Polyethylene, polypropylene, Kapton, polycarbonate, polyvinyl chloride, polyethylene terephthalate, ethylene vinyl acetate copolymers, cycloolefin copolymers, polystyrene, polyvinyl alcohols, polyvinyl acetate, polytetrafluoroethylene, polyamide, cellulose esters, polyurethanes and combinations thereof as coextrudates. Refractive indices of the above materials are typically in the range of 1.46-1.6. By choosing an appropriate combination, the refractive index can be chosen in this range. In the case of FIG. 3A, the refractive index of the matrix of the black cover 20 (e.g. matrix 41 of FIG. H. is less than 0.2, preferably less than 0.02, in particular less than 0.01.

In a preferred exemplary embodiment, in order to incorporate the soot particles 42 into the matrix 41, the soot particles can first be dispersed in low-viscosity additives or solvents which wet the soot particles well. This dispersion, also referred to as slurry, is then worked into the material of the matrix after degassing in a vacuum. In this way, a risk of air pockets that can lead to additional reflections, be reduced and an agglomeration of soot particles to larger particles are at least reduced.

FIG. 3B shows a modification of FIG. 3A, in which the copy carrier has a cover film 33 on the photopolymer 31 in addition to the carrier film 30 and the photopolymer 31 . The cover film 33 can also be formed from the above-mentioned thermoplastic materials that can be processed as a film. In this case, the matrix of the black cover 20 has a refractive index which is adapted to the refractive index of the cover film 33, which in this case represents the layer of the copy carrier adjacent to the black cover 20. In this case, too, there is only a small jump in the refractive index at the boundary surface 32, corresponding to a low level of reflection.

In the exemplary embodiments of FIGS. 3A and 3B, the black cover 20 is firmly connected directly to the copy carrier. In some exemplary embodiments, the cover film 33 (together with the black cover 20) can be detachable from the photopolymer. In other embodiments, the black cover may be attached to the copy substrate by means of an adhesive film (tacky film). This can be designed as a detachable connection in order to be able to remove the black cover in a simple manner from the then exposed copy carrier after exposure. Such a detachment is necessary if ultimately a transparent hologram is to be produced by exposing the photopolymer 31 .

A corresponding exemplary embodiment is shown in FIG. 3C. This is based on the exemplary embodiment in FIG. 3B and has the same copy carrier made of carrier film, photopolymer and cover film as the exemplary embodiment in FIG. 3B. The exemplary embodiment in FIG. 3C has a combination of an adhesive film 34 and a black carrier film 35 as a black cover. The black carrier film 35 can be formed as explained with reference to FIG. If a detachable connection is desired, the adhesive film 34w preferably has an adhesive strength of less than 60 cN/cm (centinewtons per centimeter), preferably less than 20 cN/cm, particularly preferably less than 10 cN/cm. With such a small adhesive force, the black cover can be easily peeled off. In such a structure, the materials are selected in such a way that even a refractive index difference at the interface between the adhesive film 34 and the black carrier film 35 (e.g. between a material of the adhesive film 34 and a matrix material of the black carrier film 35) is close to zero, ie less than 0.2. is preferably less than 0.02 and particularly preferably less than 0.01 in order to suppress reflections at this interface. The adhesive film 34 is formed of an optically transparent material. It has low absorption, ie it is crystal clear, so that the adhesive film 34 does not cause any additional scattering. In this case the adhesive film 34 is located at the interface 33 and is index matched to the corresponding adjacent layer of the copy substrate, in this case the covering foil 33. A corresponding black cover as a combination of adhesive film 34 and black carrier film 35 can also be used for the copy carrier of FIG. 3A. In this case, the refractive index of the adhesive film 34 is then matched to the refractive index of the photopolymer 32 .

Possible materials for the adhesive film 34 include silicones, urethanes, acrylates, or epoxies. In particular, the following materials can be used:

Pure acrylates, e.g. 2-ethylhexyl acrylate, isooctyl acrylate, butyl acrylate, methyl acrylate, vinyl acetate (solvent-based for black covers firmly bonded to the copy carrier)

Modified acrylates (aqueous dispersions for residue-free removable black covers) Elastomers such as styrene isoprene thermoplastic elastomers - SIS; Styrene Ethylene Butylene Styrene - SEBS (hot melt adhesives for firmly bonded black covers)

Natural rubber (radiation-crosslinking or hot-melt adhesive, depending on the modification for firmly bonded or residue-free removable black covers) Polyurethane (radiation-crosslinked, depending on for permanently bonded or residue-free removable black covers)

Silicones (2-component systems or radiation-curing, depending on the modification for residue-free removable or permanently bonded black covers) Epoxy systems (2-component systems or radiation-curing, depending on the modification for residue-free removable or permanently bonded black covers)

The described black covers, in addition to covering an interface such as copy substrate interface 32, can also be used to cover other areas, as shown for the apparatus of Figure 1 for black covers 14A, 14B and 14C. To measure the degree of reflection achieved by the black cover, proceed as follows. A high-resolution UV-VIS-NIR spectrometer with an additional module suitable for reflection measurements is used as the measuring device. An example is the JASCO device V-770 +ARMN-920. For the measurement, the measuring device first measures a highly reflective reference sample (back reflection almost 100%). This measurement provides the 100% baseline.

Then the measuring device measures a light trap (0.0000% back reflection) as a further reference sample. This measurement provides the 0% baseline (also called dark measurement).

Next, the measuring device measures an unblackened sample of the material whose interface is to be blackened, e.g. the copy medium without a black cover. This measurement provides the reference basis for assessing the blackening to be achieved. The measurement includes a back reflection, which (in the case of transparent media such as must be used with copy carriers) consists of equal parts of the Fresnel reflection of the first (front) and the Fresnel reflection of the second (rear) interface of the copy carrier.

The measuring device receives the blackened sample, whereby the light falls on the first interface and a Fresnel reflection occurs (e.g. at approx. 4%). If the actually observed value of the reflection is then greater than a threshold value, e.g. 4.1%, the blackening is insufficient (0.1% additional reflection through the area covered with the black cover with 4% reflection at the front boundary surface). In exemplary embodiments, a degree of reflection of less than 0.05%, preferably less than 0.01%, is achieved.

Such copy carriers with black covers can then be used to produce holograms using the device 10 of FIG. FIG. 5 shows a flow chart of a corresponding method for producing a hologram according to an exemplary embodiment. The method of Figure 5 will be performed with reference to the above description of the apparatus 10 of Figure 1 and the description of copy substrate assemblies made with reference to Figures 2-4.

In step 50 of FIG. 5, a copy carrier is placed on a master hologram, as is shown for the copy carrier 13 and the master hologram 12 in FIG.

In step 51, a black cover having the properties discussed above is then provided on at least one interface of the copy substrate. The black cover may also be provided on other interfaces as shown for black covers 14A, 14B and 14C of FIG. Steps 51 and 50 do not have to be performed in the order presented. For example, the black cover can be placed first on an interface of the copy substrate are applied and then the copy carrier with the black cover are arranged on the master hologram.

In step 52, exposure then takes place as shown in FIG. 1 for the light 16, as a result of which the structure of the master hologram is transferred to the copy carrier.

Then the process of Figure 5 can be repeated with a new copy substrate.

As previously mentioned, the above embodiments are provided for illustrative purposes only and are not to be construed as limiting.

Claims

patent claims

A copy carrier arrangement, comprising: a copy carrier (13) which comprises a photosensitive material (31), and a black cover (14A-C; 20) which is arranged on at least one side of the copy carrier (13) and which contains light-absorbing carbon black particles (42) and carrier material ( 34; 41), wherein a refractive index difference between the copy substrate (13) and the substrate (34; 41) at an interface (32) between the black cover (14A-C; 20) and the copy substrate (13) is less than 0, 2.

2. Copy carrier arrangement according to claim 1, wherein the soot particles have a size smaller than 500 nm.

3. Copy carrier arrangement according to claim 1 or 2, wherein the carbon black particles have a BET surface area according to ASTM D 6556 of greater than 200 m ² / g.

4. Copy carrier arrangement according to one of claims 1 to 3, wherein the carrier material (34; 41) comprises a matrix (41) in which the carbon black particles (42) are arranged.

The copy substrate assembly of claim 4, wherein the interface (32) is a surface of the matrix (41) that faces the copy substrate (13).

The copy substrate assembly of any one of claims 1 to 4, wherein the substrate (34; 41) comprises an adhesive film (34), the interface (32) being a surface of the adhesive film (34) facing the copy substrate (13). .

7. Copy carrier arrangement according to claim 6, wherein an adhesive strength of the adhesive film (34) is less than 60 cN/cm.

8. A copy carrier assembly according to claim 4 and according to any one of claims 6 or 7, wherein a refractive index difference between the matrix (41) and the adhesive film (34) is less than 0.2.

9. Copy carrier assembly, comprising: a copy carrier (13) which comprises a photosensitive material (31), and a black cover (14A-C; 20) which is arranged on at least one side of the copy carrier (13) and which comprises light-absorbing graphene particles and/or nanotubes and carrier material (34; 41). wherein a refractive index difference between the copy substrate (13) and the substrate (34; 41) at an interface (32) between the black cover (14A-C; 20) and the copy substrate (13) is less than 0.2.

10. Copy carrier arrangement according to claim 9, wherein the carrier material (34; 41) comprises a matrix (41) in which the graphene particles and/or nanotubes are arranged.

The copy substrate assembly of claim 10, wherein the interface (32) is a surface of the matrix (41) that faces the copy substrate (13).

12. The copy carrier arrangement according to any one of claims 8 to 11, wherein the carrier material (34; 41) comprises an adhesive film (34), the interface (32) being a surface of the adhesive film (34) which faces the copy carrier (13). .

13. Copy carrier assembly according to claim 12, wherein an adhesive strength of the adhesive film (34) is less than 60 cN/cm.

14. A copy carrier assembly according to claim 10 and according to any one of claims 12 or 13, wherein a refractive index difference between the matrix (41) and the adhesive film (34) is less than 0.2.

15. A copy carrier assembly according to any one of claims 1 to 14, wherein the refractive index difference is less than 0.02.

16. The copy carrier assembly according to any one of claims 1 to 15, wherein a reflectance of the black cover (14A-C; 20) is less than 0.05%.

17. Copy carrier arrangement according to one of Claims 1 to 16, in which the copy carrier (13) comprises a photopolymer (31) arranged on a carrier film (30).

The copy carrier assembly of claim 17, wherein the interface (32) is a surface of the photopolymer (31) facing the black cover (14A-C; 20).

19. Copy carrier arrangement according to claim 17, wherein the copy carrier has a cover film (33) on the photopolymer (31), the interface (32) being a surface of the cover film (33) which faces the black cover (14A-C; 20), is.

20. Device (10) for the production of holograms, comprising: a master hologram (12), and a copy carrier arrangement arranged on the master hologram according to one of claims 1 to 19.

The device (10) of claim 20, wherein the black cover (14A-C; 20) covers a side of the copy carrier assembly remote from the master hologram (12) and at least one side surface of the copy carrier assembly and the master hologram (12).

22. A method for producing a hologram, comprising: arranging a copy carrier (13) on a master hologram (12),

placing a black cover (14A-C; 20) on at least one surface of the copy substrate (13) to form a copy substrate assembly according to any one of claims 1 to 19 and exposing the copy substrate to an interference pattern generated by the master hologram (12).