Apparatus for copying plurality of holograms according to principle of typesetting

Abstract

The invention relates to a device for replicating a plurality of holograms. The apparatus comprises: a first carrying device for arranging a series of master elements of a plurality of master elements based on a plurality of holograms to be replicated in such a way that upper surfaces of the master elements are aligned in a horizontal plane; and a lamination module for removably laminating the photosensitive composite web onto the aligned upper surface of the master element. Further, the apparatus comprises: an exposure module for exposing the master element so as to copy the master hologram into the web of photosensitive composite; and a separation module for separating the exposed composite web from the master mask element. The master elements are removably incorporated in the first carrier device such that the sequence and / or composition of the master elements for replicating the plurality of holograms is variable. Furthermore, the master elements are merged in the first carrier such that two or more faces of the master elements are optically accessible for exposure.

Description

[0001] describe

[0002] The present invention relates to a device for replicating a plurality of holograms. The device comprises: a first carrier device for arranging a series of master elements from a plurality of master elements based on a plurality of holograms to be replicated in such a manner that the upper faces of the master elements are aligned in a horizontal plane; and a laminating module for detachably laminating a photosensitive composite web onto the aligned upper faces of the master elements. Further, the device comprises: an exposure module for exposing the master element so as to replicate the master hologram into the photosensitive composite web; and a separation module for separating the exposed composite web from the master element. The master element is detachably incorporated in the first carrier device so that the sequence and / or composition of the master elements for replicating a plurality of holograms is variable. Furthermore, the master element is incorporated in the first carrier device so that two or more faces of the master element are optically accessible for exposure.

[0003] Background and Prior Art

[0004] The invention relates to the field of hologram replication.

[0005] A holographic optical element (HOE) typically refers to an optical component that uses holographic properties to achieve a specific beam path of light (e.g., transmission, reflection, diffraction, scattering and / or deflection, etc.). Thus, the desired optical function can be implemented in a compact manner on any desired substrate. The holographic properties preferably utilize the wave properties of light, in particular coherence effects and interference effects. Here, both the intensity and phase of the light are taken into account.

[0006] Such holographic elements have applications in many areas, for example in transparent displays (e.g. in display windows, refrigeration equipment, vehicle window panes), for lighting applications (such as information or warning signals in glass surfaces), photosensitive detection systems (e.g. for interior monitoring (eye tracking in vehicles or presence tracking of people inside)). Many HOEs are of larger size, for example covering the entire windshield. Furthermore, HOEs can also be of smaller size, for example for banknotes and tamper-proof seals.

[0007] Holograms are produced by the interference of a reference beam with light reflected by the surface of an object (the object beam). Traditionally, three-dimensional objects have been used to produce unique, customized holograms. Today, such holograms can be produced using a purely computer-generated method, where the holographic interference pattern is calculated digitally and then "printed" on a photosensitive material by a coherent light source controlled by a computer. This allows holograms to be produced based on computer-generated images and is seen as particularly suitable for producing one-off holograms, producing customer-specific holograms, or producing master holograms for subsequent replication. An exemplary method of this type is known as "laser scanning holographic lithography". The method requires the use of an extremely fine laser beam with a beam width in the micrometer range. For this reason, the method is time-consuming and expensive, and is therefore not economical to use, especially in the case of very large master holograms.

[0008] In contrast, commercially available HOEs are usually mass-produced by a replication method. This replication method usually uses a master hologram with the image to be copied. Usually, the size of the master hologram is similar to that of the HOE. The materials of the master hologram are usually more expensive than the replicated HOE because the master hologram is typically made of a more durable metal or embedded in a transparent substrate with high rigidity and high surface quality as a master element. Whether using traditional methods or computer-generated methods, the production cost of the master hologram is also high due to the user-defined method used.

[0009] The master hologram is usually stored in a substrate body that carries the master hologram. Preferably, the substrate body is transparent. The substrate body preferably has multiple faces, including an upper face or a lower face that can be aligned horizontally. The combination of the master hologram and the substrate body forms a master element. Usually, the size of the master element is a multiple of the size of the master hologram. The weight of the master element is relatively large due to the hard transparent material (such as glass) used for the substrate body.

[0010] The continuous replication of a single master hologram in order to produce multiple identical copies of such a HOE is known. Usually, for the production of reflection holograms, the process is implemented by a method of embossing on a photosensitive material. The replication can also be implemented by optical exposure in order to produce a volume hologram. In these cases, the photosensitive material is brought into optical contact with the master element and exposed using coherent light. In order to allow continuous processing and increase the speed of the method, the photosensitive material can be provided in the form of a roll and conveyed by rollers through different workstations to produce the HOE. Such rolls are usually only available in standard widths, which are adapted, for example, to the width of the rollers in the workstations.

[0011] Especially for small HOEs (width or length < 150 mm), the replication on such a web using a single master element is often not efficient from a process or material point of view. Especially in cases where the width of the web far exceeds the width of the HOE, a large part of the photosensitive web must be cut off and discarded in subsequent work steps. This leads to material waste and increased costs, and also limits the speed and efficiency of the copying process.

[0012] An alternative could be to use multiple master holograms in order to produce the HOEs adjacently across the web width. This improves material utilization but creates challenges in terms of placement of the master holograms. Specifically, unevenness between the master holograms can lead to poor optical contact between the web and the master hologram, thus generating unfavorable reflections at the interface. A possible solution to this problem is to integrate multiple different master holograms in a single large-area master element. A large-area master element can provide a completely flat and continuous surface to establish the necessary optical contact with the web.

[0013] However, it is expensive to produce large-area master elements with numerous master holograms, especially since it is not easy to produce large-area optically flawlessly polished substrates. In addition, due to their weight, it is more difficult to move such master elements, making it more difficult to introduce and remove such large-area master elements in the production line. In addition, it is not practical to store a large number of heavy and expensive master elements and ensure that they are always available from a logistical point of view.

[0014] Furthermore, the spatially efficient positioning of the master holograms may lead to undesirable optical interference in the generated HOE. For example, the reference beam used to expose one master hologram may propagate or be scattered and reach an adjacent hologram, causing the adjacent hologram to be accidentally exposed as well. To avoid this, large buffer spacing is required between the master holograms; this has an adverse effect on the efficient use of materials for both the master element and the photosensitive web.

[0015] The same master hologram may be present on the master element in order to more efficiently utilize the photosensitive web as explained above. In this case, the same scanning laser may expose all master holograms from the same angle.

[0016] However, it may also be preferred to have a master hologram that is intended to replicate different patterns simultaneously. Firstly, this may be preferred in order to make the replication device suitable for multiple applications simultaneously. Furthermore, providing a large area HOE may require replicating a large number of different types of HOEs, which are then spliced ​​together to form a large area HOE.

[0017] In this case, the various holograms to be reproduced may differ from one another not only in the patterns they contain, but also in their type. For example, transmission holograms and reflection holograms are known; these are further subdivided into categories such as edge-illuminated, back-illuminated, etc. Holograms for different purposes must be exposed in different ways and from different angles, for example in order to correspond to the position of the light source intended to be used to reconstruct the hologram. In order to reduce the investment, it would also be advantageous if different types of master holograms with different patterns and using different exposure methods could be exposed on a web in the same device.

[0018] In the case where the same master element includes a large number of master holograms of different types with different patterns, it is not appropriate to simply laser scan the entire master element. It is complicated to design an optical structure that can expose different master holograms in the same master element from different angles without accidentally exposing other areas. Moreover, in this case, in order to avoid unfavorable superposition of beams, particularly large spacings are required between the master holograms in the master element.

[0019] Another problem arises if one or more of the master holograms in a master element is found to be incorrect, damaged, or altered. Because the master holograms are firmly bonded to the substrate body, they cannot be replaced individually without replacing the entire master element.

[0020] This results in a lot of wasted material and increased production costs, especially if changes need to be made to only a portion of a larger master hologram. This approach becomes impractical if changes are frequent and only small batches are produced. The alternative is to use computer-controlled photolithography to produce each hologram. However, as mentioned above, this is not economical for most commercial applications.

[0021] Therefore, it is desirable to provide a device that allows a more efficient method for replicating holograms. Preferably, the device allows easy modification, in particular for more flexible, material-saving replication of holograms of small and large sizes. In addition, it is desirable to develop a simple option for changing the master hologram between short production runs, wherein the master hologram is easy to store and replace.

[0022] Known batch replication methods are not suitable for many applications, such as the production of personalized security features (e.g., holographic date of birth, holographic issue date, holographic serial number, etc.). This is because the hologram to be produced may be unique, or contain a unique combination of features such as numbers, symbols and images. In addition, it may be necessary for these holograms to be different types with different exposure requirements. For example, glasses of a specific hue or diopter may require a transmission hologram (see WO2016202595A1). It may also be necessary that the hologram is a reflection hologram, for example for use in a display. The hologram may need to have a specific color or need to be visible only from a specific angle.

[0023] US2007024939A1 has disclosed a method for increasing the flexibility of use of master holograms in production batches. The method comprises contacting a photosensitive web with a matrix of small individual master elements. The master element itself comprises variable features, such as a counter, and is arranged in a support so that only its top side is accessible for exposure. This arrangement thus allows exposure only from one side, so as to be used exclusively for the production of reflection holograms.

[0024] Furthermore, the arrangement known from US2007024939A1 does not allow for precise guidance of the exposure light to the master element or the photosensitive web. Since the light can only be incident on the upper side of the master element, the angle at which the light incident through the photosensitive web can reach the master element is limited. Therefore, all master elements must essentially be exposed by the same technique. Even though different master elements (or "objects") may be copied in one production run, they must be copied in the same way in order to form a reflection hologram exclusively. For this purpose, the master hologram is located in front of a reflective background.

[0025] Furthermore, no protection is provided for adjacent copies from light reflected from adjacent master holograms. Exposing the master hologram from above is disclosed as the only option for producing different holograms in a light-sensitive web and avoiding unfavorable superpositions between different images. Exposure as described in said document requires that the reference beam passes through various components with different refractive indices, which are thus refracted to different degrees. There are interfaces between layers with different refractive indices (e.g. between the master element, the light-sensitive web and the surrounding air) which carry a great risk of reflections. This can lead to unfavorable exposure patterns.

[0026] DE 10 2010 2014 3015A1 has disclosed a method for replicating a plurality of reflection holograms. The holograms to be copied are arranged adjacently on the surface of a drum having a polygonal cross section or a prismatic shape, wherein each lateral face of the drum comprises at least one master hologram. For exposure, a photosensitive material is guided on the surface of the drum. A roller is guided on the surface of the drum so as to eliminate the air gap between the photosensitive material and the drum, especially at the corners of the drum. As with the device according to US2007024939A1, this arrangement only allows for exposure of reflection holograms. No higher flexibility can be provided during the exposure of different types of holograms. In addition, winding the photosensitive material on the surface of a polygonal prismatic drum may impair the mechanical quality of the photosensitive material, leaving unfavorable grooves or wrinkles. Therefore, there is a need for an arrangement that allows gentle handling of the composite web in order to carry out a flexible replication process.

[0027] In view of the known prior art, there is therefore a need for a device which not only makes it possible to replicate different master elements with different master holograms in a single batch, but which also preferably allows a controlled exposure of each master element from a specific direction or using a specific wavelength, so that different exposure methods can also be performed within a single batch.

[0028] Purpose of the Invention

[0029] The problem solved by the present invention is to provide a device for duplicating a plurality of holograms which does not have the disadvantages of the prior art. In particular, the problem solved by the present invention is to provide a device which is suitable for duplicating holograms with high precision, high quality and material saving, wherein preferably also different holograms with different exposure requirements can be duplicated. Summary of the invention

[0030] This problem is solved by the features of the independent claim. Advantageous configurations of the invention are described in the dependent claims.

[0031] The present invention relates to a device for replicating a plurality of holograms, the device comprising:

[0032] a first carrier device for arranging a series of master elements of the plurality of master elements based on the plurality of holograms to be replicated in such a way that the upper faces of the master elements are aligned in a horizontal plane,

[0033] a laminating module for removably laminating a web of photosensitive composite material onto the aligned upper face of the master element, and

[0034] an exposure module for exposing the master element in order to replicate the master hologram into a web of photosensitive composite material, and

[0035] - a separation module for separating the exposed composite web from the master element,

[0036] wherein the master element is detachably incorporated in the first carrier device such that the sequence and / or composition of the master element for replicating a plurality of holograms is variable, and wherein the master element is further incorporated in the first carrier device such that two or more faces of the master element are optically accessible for exposure.

[0037] The device according to the invention is advantageous in that a plurality of master holograms can be exposed in a single batch, while providing great flexibility in the exposure method. By providing a plurality of master elements and a linear arrangement thereof, the size and weight of each master element can be reduced. Thus, a large hologram can be formed from a plurality of smaller patterns. These smaller patterns can be part of a larger image or appear as independent components. In addition or in an alternative, the master elements can represent independent holograms intended to be separated after copying.

[0038] By using a plurality of relatively small master elements to cover an area that is usually covered by a single large master element, the complexity of the system can be reduced. A minor change or defect in one master element does not require the replacement of all the master elements. This significantly reduces costs. For example, the transparent substrate for accommodating the master hologram can thus be prepared and polished more easily. The transport and storage of smaller and lighter master elements is also more economical, because these can be stacked in a space-saving manner, can be transported without special lifting equipment, and can be easily inserted into or removed from the device.

[0039] In addition, the device according to the invention allows for optimal utilization of the material of the light-sensitive composite web. Preferably, the carrier device can extend over the entire width of the composite web, so that the master hologram can be replicated in the region of the composite web over the entire width of the composite web. Furthermore, in this case, the provision of a first carrier device advantageously allows the individual master elements to be optically separated from one another, thereby avoiding the generation of stray light during the exposure process. This allows individual master elements to be placed in the device so that the replicated holograms can be positioned significantly more densely in the composite web, without affecting the accuracy or quality of the replication.

[0040] Furthermore, a library of different components can be provided by providing a plurality of such master elements. Selecting a master element from such a plurality of master elements enables a diverse spectrum of component combinations to be reproduced on a single photosensitive material. This provides great flexibility in the combination of components in order to produce a wide variety of images, patterns or texts, wherein the costs are significantly reduced compared to the production of digitally controlled individual holograms.

[0041] By selecting a master element from a number of master elements according to a sequence, individual holograms can be produced exactly in the quantity and order desired by the consumer. This is particularly useful in industries that use sequential part delivery (SPD) or just-in-sequence (JIS) delivery methods, facilitating the integration of the device according to the present invention into such a factory. Taking the automotive industry as an example, which is increasingly inclined towards customization and integrating more HOEs in car construction, the replicated holograms can be supplied in a sequence that is consistent with the car production sequence. Therefore, intermediate logistics steps can be omitted, thereby improving efficiency. In addition, there is less waste because only the exact required quantity is produced. The device is also suitable for applications with high security requirements such as banknotes and identity documents.

[0042] In addition, the first carrier device advantageously allows the individual master elements to be placed in the device so that they are at a fixed, known distance from one another. This ensures a high degree of precision in the placement process, thereby allowing the replicated holograms to be separated accurately and linearly. The first carrier device also enables the master elements to be placed accurately so that their surfaces are flush with one another and with the carrier device. Thus, even with thin, flexible photosensitive materials, a large number of master elements can be used without damaging them. In this respect, this is contrary to previous views, according to which the use of a plurality of adjacently arranged master elements in a single iteration can cause wear or damage to the moving composite web made of photosensitive material due to edges or protrusions.

[0043] In contrast, due to the aligned horizontal surfaces produced by the combination of master element and carrier device, the photosensitive material can be laminated onto the master element with high precision and only low shear forces.

[0044] The lamination module preferably brings the photosensitive material into mechanical contact with the master element and ensures sufficient optical contact with the master hologram. Due to the lamination rather than simply placing the photosensitive material on the master element, a particularly uniform contact can be established between the master element and the photosensitive material, so that bubbles or wrinkles are effectively avoided. Due to the use of a composite web made of photosensitive material, this can be efficiently and repeatedly implemented on the arrangement of the master element, so that the composite web moves while the arrangement of the master element preferably remains stationary. The detachable lamination in particular allows the composite web to be removed without damage and residue and allows it to be run on another station in the production line. Preferably, the exposure module directs light to the composite web and / or the master element in order to copy the master hologram contained in the master element into the composite web.

[0045] The separation module preferably ensures that the composite web is separated from the master element without residue with sufficient force, while at the same time not damaging the web.

[0046] The integration of lamination, exposure and separation modules in the same system allows for a very compact system design; this is particularly suitable for small batches and customer-specific end products.

[0047] By configuring the support device so that at least two faces of each master element remain optically accessible, the same pass of the composite web through the device can include simultaneous exposure of a reflection hologram and a transmission hologram. For example, the upper horizontal face of the first master element can be exposed from above so that light passes through the light-sensitive composite web, reflects from the master hologram, and then passes through the light-sensitive composite web again. This will produce a reflection hologram. The second master element can be exposed from the side or from below so that light passes through the master hologram and then through the light-sensitive composite web, producing a transmission hologram.

[0048] The device thus allows for greater flexibility by producing a number of different holograms with different properties in the same pass.

[0049] Within the meaning of the present invention, a "module" preferably refers to a workstation in a continuous manufacturing method, preferably equipped with the technical means required for carrying out the method steps. Different modules can, but do not have to, be separated from one another by housings or partitions. Within the meaning of the present invention, it can be preferred that the laminating module, the exposure module and the separation module are located in the same housing.

[0050] Within the meaning of the present invention, a "sequence" preferably refers to a plurality of elements in a specific order. The elements in a sequence may be identical and repeated, or may vary. The order is preferably predetermined.

[0051] Within the meaning of the present invention, an "arrangement" is preferably a physical positioning of elements at predetermined positions, preferably according to a predetermined order.Preferably, the arrangement of the master elements is a linear arrangement.

[0052] Within the meaning of the present invention, a "linear arrangement" is preferably a physical positioning of elements such that the elements form a line along one of their edges, along their center and / or along another reference point. Preferably, a "linear arrangement" may comprise a plurality of lines, for example forming rows and columns.

[0053] Within the meaning of the present invention, a "carrying device" is preferably a device that holds a plurality of elements so that their positions relative to each other are fixed. Preferably, the carrying device comprises a frame, a framework and / or a plurality of fixtures, wherein the fixtures may be associated with a common mechanical reference, such as a guide rail. Preferably, the carrying device comprises gaps and / or recesses designed so that they precisely cooperate with a master element.

[0054] Within the meaning of the present invention, "lamination" or "laminating" is preferably a joining method between two components. Lamination is preferably designed so that the composite web covers the area in such a way that there are no gaps, bubbles or wrinkles in the entire area. Preferably, lamination is implemented by laminating rollers. In this case, lamination is preferably implemented at room temperature, for example at a temperature of 20° C. to 25° C. However, the laminating roller can also be optionally heated to 20° C. to 300° C., preferably 20° C. to 100° C. or 40° C. to 80° C. Preferably, the temperature of the laminating roller can be set so that the composite web softens but does not melt. Lamination is preferably designed so that no permanent bond is established between the composite web and the master element or the carrier. Lamination can also be implemented with the aid of an auxiliary agent such as an adhesive, wherein the adhesive is preferably weak so that the parts can be separated from each other with a force of less than 10N, preferably less than 5N. Preferably, the adhesive is easy to clean, for example soluble in water, and does not leave residues on the composite web. More preferably, the adhesive evaporates without residue at room temperature.

[0055] Within the meaning of the present invention, a "composite" is preferably a multilayer material consisting of two or more different components with different physical properties, which components are bonded to each other at an interface. Preferably, the bond between the individual components is constructed so that it cannot be separated by the influence of slight forces and is therefore considered permanent. The composite can consist of a light-sensitive liquid, solid or resin, for example, which is enclosed between two transparent carrier films. Alternatively or in addition, the composite web can include a stack of layers, each layer being light-sensitive to a different spectral range.

[0056] Within the meaning of the present invention, a "composite web" is preferably a composite material whose length is at least twice, preferably at least five times, even more preferably at least twenty times, greater than its width. For example, the thickness of the composite web is preferably set so that it has a certain flexibility so that it can be partially wound on a roll. Preferably, the composite web has a thickness of up to 300 μm. The composite web comprises a photosensitive material. Preferably, the composite web encloses the photosensitive material between two transparent carrier films, the refractive index of which is similar to that of the photosensitive material. Preferably, the refractive index of the carrier films and the photosensitive material is between 1.4 and 1.6. The photosensitive material can be, for example, a photosensitive photopolymer or dichromated gelatin. The photosensitive material can be photosensitive to the entire visible spectrum or wavelength selective.

[0057] Within the meaning of the present invention, "exposure" is preferably understood to mean the targeted steering of an electromagnetic beam onto a suitably sensitive surface, preferably for forming a hologram. Different methods of exposing holograms are known; these methods include transmission or reflection techniques for producing volume holograms. Examples thereof are explained in detail below within this document.

[0058] A "master element" is preferably a three-dimensional unit which comprises a master hologram in a form which is advantageous for its handling and movability. In particular, the master hologram is surrounded by the master element in a positionally fixed manner, so that a movement of the master element directly results in a corresponding movement of the master hologram. Preferably, the length and width of the master element correspond approximately to the length and width of the master hologram. Preferably, the height of the master element is at least twice, preferably five times, particularly preferably at least twenty times, the height of the master hologram. The master element preferably has a regular shape, so that a mosaic-like or linear arrangement can be achieved.

[0059] The master element comprises a substrate body, which encloses or carries the master hologram. In an embodiment, the master element may comprise, for example, a transparent upper cover for protecting the master hologram present between the cover and the substrate body. Preferably, the upper cover has a refractive index that has been selected so that light passes through the upper cover, the master hologram and the substrate body, and substantially no reflection occurs at the interface between the substrate body, the master hologram or the cover. For example, the upper cover may be a transparent film or a glass layer. Preferably, the materials of the substrate body, the master hologram and the cover are selected so that the difference in refractive index between the layers is small. This allows to avoid internal reflections.

[0060] Preferably, "width" relates to the dimension in a horizontal plane transverse to the direction of travel of the composite web. Preferably, "length" relates to the dimension in a horizontal plane along the direction of travel of the composite web. Preferably, "height" relates to the dimension in a vertical plane, which is orthogonal to the plane formed by the width and the length.

[0061] Within the meaning of the present invention, a "substrate body" is preferably a three-dimensional material block that carries or encloses a master hologram. Preferably, the substrate body is transparent. The substrate body preferably has a plurality of faces, including an upper face that can be aligned horizontally.

[0062] Within the meaning of the present invention, the term "transparent" or "transparency" preferably relates to the property of a material, whereby it is substantially transmissive to light. Preferably, within the meaning of the present invention, a transparent material is transmissive at least to a portion of the electromagnetic spectrum preferably having a wavelength between 100 nm and 1 mm, particularly preferably between 400 nm and 780 nm. Particularly preferably, the transparent material (e.g. a transparent substrate body) is transmissive to light in the wavelength range used when exposing the master hologram. The transparent material can also be colored in such a way that it selects for light radiation of a specific wavelength.

[0063] Within the meaning of the present invention, a "master hologram" is preferably a holographic optical element comprising at least one hologram to be replicated. The master hologram is designed for optical functions (e.g. diffraction, reflection, transmission and / or refraction) for one or more wavelengths. For this purpose, for example, multiple holograms each diffracting a wavelength of light and / or multiple holograms diffracting multiple wavelengths of light can be arranged as a hologram stack. For example, the master hologram can be a diffractive optical element (DOE). The diffractive optical element (DOE) uses a surface concave-convex profile with a microstructure to achieve its optical function. In an alternative, the microstructure can also exist in the volume of the element in the form of local differences in refractive index. The light transmitted by the DOE can be converted into almost any desired distribution by diffraction and subsequent propagation. This can involve images, logos, texts, light refraction patterns, etc. In addition, the master hologram can be a technical hologram, such as a Bragg reflector, a diffuser, or a hologram acting as a lens.

[0064] The process for producing a master hologram may preferably be referred to as "hologram origination" or "hologram mastering". A master hologram may be produced by analog or digital methods. In an exemplary analog method, a first coherent light beam (object beam) is reflected from an object onto a recording material, which is simultaneously subjected to a second coherent light beam (reference beam). On the recording material, the object beam and the reference beam interfere to produce an interference pattern. This interference pattern or fringe pattern is recorded by a photosensitive material and, after processing, takes the form of a surface relief pattern on the surface of the material or a spatially varying refractive index of only a few microns below the surface. In order to view the image of the original object, the master hologram may be illuminated with light diffracted by the recorded surface relief pattern or refractive index pattern. The diffracted light beam contains the image of the original object. Then, when additional copies with the same image are produced, the master hologram may be used as a new object.

[0065] The master hologram can also preferably be computer generated. Microscopic gratings that generate diffraction effects can be produced, for example, by laser interference lithography. In this technology, two or more coherent light beams are configured so that they interfere at the surface of the recording material. The position of the light beam relative to the recording material can be controlled by a computer. Depending on the intensity of the laser, the recording material can be composed of almost any material. Other techniques such as electron beam lithography can also be used for the digital production of master holograms. The master hologram can preferably include glass, silicon, quartz, UV paint, photopolymer composites and / or metals such as nickel.

[0066] Within the meaning of the present invention, an "optically accessible surface" is one in which at least 50%, preferably at least 60%, 70%, 80% or 90%, particularly preferably 100%, of the surface is not covered by optically absorbing material. In particular, there is no optically absorbing material between the relevant surface and the light source used for exposure. Depending on the shape of the master element, in some cases, an opaque frame of the carrier device may cover part of the optically accessible surface. Preferably, the frame covers no more than 50%, preferably no more than 40%, 30%, 20% or 10% of the optically accessible surface. Preferably, the optically accessible surface is also not very reflective. Preferably, the reflectivity of the optically accessible surface for visible light at normal incidence may be less than 50%, preferably less than 40%, less than 30%, less than 20% or less than 10%. In some preferred embodiments, the optically accessible surface comprises an anti-reflective coating (AR coating). This can improve the utilization of the incident light in the exposure of the composite web.

[0067] In a preferred embodiment of the invention, the apparatus comprises a transport module for transporting a web of photosensitive composite material over the series of master elements. Preferably, the transport module comprises one or more transport rollers, such as traction rollers, which move the web of composite material forward. This can produce a semi-continuous process with a web-like intermediate product that can be transported to a further workstation for cutting.

[0068] In a further preferred embodiment of the invention, the master elements are separated along a linear arrangement in the first carrier device, wherein the master elements are preferably separated by light absorbing spacers and / or wherein a light absorbing layer is applied on vertical faces of the master elements.

[0069] Preferably, the first carrier device is mounted so as to be tiltable and / or height-adjustable, wherein the apparatus for replicating a master hologram preferably comprises a device for setting the tilt angle of the first carrier device and / or adjusting the height of the first carrier device. Within the meaning of the present invention, such a device may also be referred to as an alignment unit of the first carrier device and is known to a person skilled in the art. An exemplary device for setting the height adjustment of the first carrier device comprises an adjustment table with an actuator for moving up and down. Thus, the first carrier device and the master element contained therein can be brought into contact with further process components, in particular a composite web, an optical adhesive film, a laminating roller and / or one or more input coupling elements.

[0070] The device for setting the tilt angle may preferably also comprise an adjustment stage, wherein the tilt angle of the first carrier (e.g. relative to the plane of the composite web) can be set by means of suitable actuators. Advantageously, this can ensure a particularly plane-parallel alignment of the master element located in the first carrier relative to the composite web or the input coupling element (described below). In this case, a rotation of the entire first carrier allows a consistent alignment of the master element.

[0071] In this case, the device for setting the inclination angle of the first carrier device and / or adjusting the height of the first carrier device preferably allows fine adjustment with a height adjustment accuracy of at least 10 μm, preferably at least 5 μm, and / or allows the inclination angle to be set with an accuracy of at least 0.1°, preferably at least 0.01°.

[0072] Alternatively or additionally, the further process components are mounted in a height-adjustable manner so that sufficient contact is established between the process components to perform the replication method. The further process components may include: transport rollers or transport components for positioning the composite web, possible input coupling elements, laminating rollers, dosing units for applying optical liquids, or rollers for applying optical adhesive films. These components are explained in more detail below. The height adjustability of the process components preferably allows fine adjustment of their position with a height adjustment accuracy of at least 10 μm, preferably at least 5 μm.

[0073] In a preferred embodiment, the first carrier device is cushioned. The cushioning can have an active or passive configuration and is preferably designed to allow an upward and downward movement of the first carrier device. The cushioning is preferably implemented mechanically, (electro)magnetically, hydraulically or pneumatically, with pneumatic cushioning being particularly preferred. Preferably, the cushioning is configured for a height adjustment of at least 20 μm, preferably at least 50 μm, particularly preferably at least 100 μm, and / or at most 1000 μm, preferably at most 500 μm, particularly preferably at most 200 μm.

[0074] Preferably, the buffering of the first carrier is pressure-regulated, in particular in order to establish and maintain a preferred pressure between the laminating roller and the respective master element. The buffering of the first carrier preferably allows the first carrier to be brought into contact with other process components while compensating for all tolerances in the surface flatness of the master element. Advantageously, the provision of a buffered first carrier also allows possible height differences between the individual master elements located in the first carrier to be compensated during the replication process. The tilted position of the first carrier can also be compensated. As explained in more detail below, it can be preferred, for example, to use a laminating roller to apply the composite web to the master element. For this purpose, the laminating roller preferably sweeps over the composite web and the master element below in sequence, wherein the optimal height or pressure conditions are set for each swept master element by the buffering of the first carrier. For example, due to the buffering, the first carrier can also be slightly moved up and down synchronously with the laminating roller to compensate for the height differences between the master elements. Thus, all master elements can be brought to the desired height precisely.

[0075] Production tolerances or damage to the surface of the master element can also be compensated. Air gaps or bubbles between the surface of the master element and the composite web and / or the incoupling element are eliminated, improving the optical contact between the master element and further process components.

[0076] In another preferred embodiment of the present invention, the master element can be positioned in a buffered manner in the first carrier. Therefore, the first carrier can preferably also include means for buffering the master elements separately, in particular independently of each other. For example, the base of the first carrier can be provided with an elastic material, such as foam.

[0077] This makes it possible to compensate for changes in the dimensions of the master element in the first carrier device, for example so that the composite web can be clamped without gaps between the planar input coupling element and the master element.

[0078] In a preferred embodiment of the invention, the apparatus comprises one or more optically transparent input coupling elements, wherein the input coupling elements can be applied to a composite web laminated on a master element such that, during exposure, partial sections of the composite web are captured between the one or more input coupling elements and the master element. The apparatus can be used to arrange one or more optically transparent input coupling elements on a laminated composite web such that, during exposure, partial sections of the composite web are captured between the one or more input coupling elements and the master element.

[0079] Within the meaning of the present invention, "input coupling elements" are preferably three-dimensional blocks made of transparent material, which have a refractive index and dimensions configured such that they direct the exposure beam to the master hologram and / or direct the exposure beam away from the master hologram. Preferably, the input coupling elements can have any desired three-dimensional shape, in particular a parallelepiped shape, a wedge shape, a cylindrical shape, a prismatic shape and / or a prismatic shape with a semicircular or semi-elliptical cross section. Preferably, the input coupling elements can have different optically accessible faces. Preferably, at least one side or base and an underside or lateral face of the input coupling element are optically accessible. Preferably, the optically accessible face of the input coupling element is also not very reflective. Preferably, the reflectivity of the optically accessible face for visible light at normal incidence may be less than 50%, preferably less than 40%, less than 30%, less than 20% or less than 10%. In some preferred embodiments, the optically accessible face comprises an anti-reflective coating (AR coating). This can improve the utilization of the incident light in the composite web exposure.

[0080] An input coupling element can be used to direct the exposure beam onto the side above the master hologram. The angle of the exposure beam can be selected so that the exposure beam otherwise passes under the input coupling element and reaches the master hologram and is then reflected back through the composite web. By means of the input coupling element, the reflected light is diverted in such a way that it is not incident on adjacent parts of the composite web and its scattering is minimized. Alternatively, the light can also be directed through the master hologram in order to expose a transmission hologram into the composite web.

[0081] The input coupling element can also be used to fix the composite web above the surface of the master element. Since the input coupling element does not need to be replaced between batches, a single plate can be used to cover all linearly arranged master elements in the carrier. Therefore, there is no risk that the edge of the input coupling element can leave marks on the composite web. Furthermore, the alignment of the input coupling element above the carrier is facilitated.

[0082] However, it may be preferred to use a plurality of input coupling elements. This reduces the size and weight of each input coupling element and facilitates storage and replacement. Furthermore, this provides advantages in terms of the quality of the input coupling elements, since polishing equipment for the materials used generally has a maximum size limit. By limiting the size of the input coupling elements in this way, a high polishing grade can be achieved.

[0083] It may be particularly advantageous if the length and width of the contact surface of the input coupling element with the composite web is the same as the length and width of the contact surface of the master element with the composite web and that these contact surfaces are arranged in close proximity to each other. This allows the two elements to be accurately assigned to each other and if the input coupling element leaves marks or traces on the composite web, these marks or traces will be located in the buffer area between the replicated holograms. In a preferred embodiment, the input coupling element and the master element may have the same substrate body in terms of size and shape. In this way, the substrate bodies can be produced and stored in larger quantities more cost-effectively.

[0084] In another preferred embodiment of the present invention, each motherboard element is assigned a corresponding input coupling element. Preferably, at least the bottom surface of the corresponding input coupling element is consistent with the top surface of the corresponding motherboard element.

[0085] In another preferred embodiment of the invention, the input coupling elements are arranged on a second carrier device that is height-adjustable. The second carrier device may be configured similarly to the first carrier device. In particular, the second carrier device (in a manner similar to the preferred embodiment of the first carrier device) is mounted in a tiltable and / or height-adjustable manner. Likewise, it may be preferred that the up and down movement of the second carrier device is buffered. It may be preferred that the second carrier device comprises light-absorbing spacers between the input coupling elements. This may prevent the light beam from reaching adjacent input coupling elements or from being reflected into adjacent parts of the composite web.

[0086] The second, height-adjustable carrier device can be used to bring the incoupling element into contact with the composite web, preferably after lamination of the composite web and before exposure thereof.

[0087] In this case, it may be preferred that lamination and exposure are performed on the same stretch of the composite web. During the lamination process, the second carrier device with the input coupling element may be kept at a distance (first height) from the composite web. The composite web may be laminated by means of a roller, which is lowered onto the composite web and rolled on the composite web so as to bring the composite web into close contact with the aligned horizontal surface of the master element. Preferably, the lamination roller and / or the master element may be cushioned so that contact between the two components is maintained despite changes in the surface position or surface quality of the components. The lamination roller may then be raised or withdrawn so that the input coupling element may then be lowered so as to establish contact with the composite web (second height). In the position of the input coupling element, the composite web is thus clamped between the input coupling element and the master element.

[0088] The exposure can be carried out both via the master element and via the input coupling element. Once the exposure has been completed, the input coupling element can be raised again to the first height position at a certain distance. Optionally, the fixing can be carried out in situ and the composite web can be separated from the surface of the master element, for example by raising one or more parts of the composite web that are located outside the first carrier of the master element from below by one or more further rollers. The first carrier remains accessible, so that the sequence of the master elements can be changed. This allows a plurality of process steps to be carried out in a single area. This increases the compactness of the method performed by the device according to the invention.

[0089] In a preferred embodiment of the invention, the same input coupling element is used for exposing various master elements. In this case, for the exposure, the contact surface of the input coupling element can cover the surface of all master elements in the first carrier device. For example, an input coupling element in the form of a parallelepiped input coupling plate can be used, the length of which extends over all master elements. Alternatively, the input coupling element can be moved over the surface of the master element, wherein the exposure is preferably carried out synchronously with the movement of the input coupling element. The movement of the input coupling element can preferably be a push or rolling movement.

[0090] Preferably, one or more input coupling elements are configured such that only a limited area is in contact with the composite web at any time during the exposure process. Preferably, this area is referred to as a "contact surface" within the meaning of the present invention. In particular in the case of input coupling elements designed to roll on the composite web, the contact surface of the input coupling element can be continuously displaced while maintaining the same size.

[0091] In a preferred embodiment of the invention, the contact surface of the input coupling element is curved or planar. If a curved contact surface is used, lensing effects should preferably be avoided. As explained below, depending on the application, it may be preferred to use a curved or planar surface.

[0092] In another preferred embodiment of the invention, the input coupling element has a cylindrical shape. Preferably, such an input coupling element can act as a roller and can be rolled or pushed on the composite web. Thus, the cylindrical input coupling element can establish optical contact with the composite web along one axis. Light from the lateral face and / or the base can be diverted to the composite web and the master element via the input coupling element. Preferably, the light source and / or the light deflection component moves synchronously with the input coupling element in order to expose the master element.

[0093] In another preferred embodiment of the present invention, the cylindrical input coupling element is mounted in a manner similar to a laminating roller, wherein the cylindrical input coupling element is preferably mounted in a height-variable, height-adjustable, cushioned and / or pressure-adjustable manner. Such a mounting can improve the optical contact between the input coupling element, the composite web and the master element. Preferably, one or more support rollers, preferably three support rollers, are also provided for mounting and / or moving the input coupling element.

[0094] In a preferred embodiment of the invention, the cylindrical input coupling element itself acts as a laminating roller and vice versa. The cylindrical input coupling element can thus also improve the mechanical contact between the composite web and the master element. In this arrangement, the lamination is preferably carried out synchronously with the exposure. In this case, no separate laminating roller is required. This saves space in particular and increases the output efficiency of the method. Another advantage of using a cylindrical input coupling element is that the contact surface between the input coupling element and the composite web is small. Such a small contact surface is particularly advantageous when an optical fluid is used between the input coupling element and the composite web. Firstly, the amount of optical fluid used can be kept to a minimum. Secondly, the force required to remove the input coupling element from the composite web is also reduced. Thus, the cylindrical input coupling element can be removed in a particularly gentle manner on the composite web. This will be explained in detail when it comes to the use of optical fluids.

[0095] In another preferred embodiment of the invention, the input coupling element has a prismatic shape with a semicircular cross section. The shape of such an input coupling element may preferably correspond to the lower half of the roller and may comprise two lateral faces: a curved lateral face and a flat lateral face. Preferably, the curved lateral face is brought into contact with the composite web on the surface of the master element and pushed on this surface. This allows the weight of the input coupling element to be kept to a minimum. In addition, the input coupling element has a narrow contact surface with the composite web; this is advantageous when using optical fluids. When using such an input coupling element for exposure, a lens function should preferably be avoided.

[0096] In another preferred embodiment of the invention, the input coupling element has a prismatic shape with at least one flat surface, which preferably serves as a contact surface for application to the composite web. Preferably, the cross section of the input coupling element tapers towards the flat contact surface, so that within the meaning of the invention the prismatic shape can also be referred to as a wedge shape. For example, the cross section of the input coupling element or at least one section of the input coupling element can have the shape of an isosceles trapezoid, wherein the shorter base of the trapezoid is in contact with the composite web as a flat surface. This embodiment allows an optimal setting of the contact surface between the input coupling element and the composite web; in particular, its contact surface can also be selected to be larger than the contact surface of a cylindrical input coupling element, in which the contact surface corresponds essentially to a line, depending on the size of the curvature. In particular when using optical fluids, the larger contact surface can remain frictionless and gap-free during the displacement of the input coupling element. The increased capillary forces between the contact element and the composite web also advantageously suppress the formation of gaps, so that there is a particularly good optical contact.

[0097] In a further preferred embodiment of the invention, the contact between the input coupling element and the composite web on the surface of the master element is effected under a predetermined pressure. For this purpose, a compression force sensor or a pressure sensor is preferably provided for measuring the compression force or pressure between the input coupling element and the master element. Preferably, the film coating can preferably be used as a sensor for the pressure exerted by one process component on another process component, wherein the pressure sensors are distributed over the entire film (so-called "pressure measuring film"). Such a pressure measuring film is preferably applied to areas of the process component that are not used for exposure (e.g. edge areas) and is particularly compact.

[0098] In another preferred embodiment of the invention, the lower side of the input coupling element is formed by a deformable transparent input coupling section. In some embodiments of the invention, the use of such a deformable input coupling section is particularly preferred if the input coupling element is only moved up and down relative to the master element. Preferably, the input coupling element with the deformable input coupling section neither rolls nor shifts on the surface of the composite web in contact with the master element.

[0099] Within the meaning of the present invention, an "input coupling segment" is preferably a portion of an input coupling element which consists of a transparent deformable material and is designed such that it ensures complete optical contact between the input coupling element and one or more master elements. Preferably, the refractive index of the input coupling segment is the same as or within the range of + / -20%, preferably + / -10%, more preferably + / -5% of the refractive index of the body of the input coupling element, the composite web, the upper cover of the master element, the master hologram and / or the substrate body of the master element.

[0100] The deformability of the input coupling section allows it to be pressed onto the composite web when it is located on the aligned surface of the master element in such a way that no gaps or air bubbles remain. This ensures a particularly uniform optical contact between the three elements of the sandwich. Unfavorable optical aberrations or patterns are avoided, whereby the final product has a higher quality.

[0101] In another preferred embodiment of the invention, the material of the input coupling section is selected such that its shear modulus is at least 10 kPa, preferably at least 100 kPa, more preferably at least 1 MPa. It may also be preferred that the Young's modulus of the material of the input coupling section is between 1 MPa and 50 MPa. It may also be preferred that the refractive index of the material is between 1.4 and 1.6. As far as materials are concerned, silicone has been found to be particularly suitable for obtaining a sufficient refractive index while being sufficiently elastic, easy to clean, and not leaving any residue on the composite web.

[0102] The laminating module preferably comprises a laminating roller. The laminating roller can be accommodated in the device in a height-adjustable manner and rolls along a predetermined trajectory so as to press the composite web onto the top side of the master element. It may be advantageous that the laminating roller is accommodated so that it can move along a predetermined path, wherein the laminating module preferably comprises an actuator for moving the laminating roller along the path. The actuator is preferably controlled by a control unit. Preferably, the path comprises a diagonal descent of the laminating roller from a first height not directly above the first carrier and a first lateral position in a direction above the first master element. The path also preferably comprises a horizontal rolling movement of the laminating roller along the top side of the master element at a second height below the first height until the roller reaches the last master element n in the sequence. The laminating roller is preferably configured so that during exposure for the sequence, it is maintained at a second lateral position at a second height and downstream of the last master element.

[0103] In a preferred embodiment of the invention, the laminating module comprises a device for adjusting the height of the laminating roller. Preferably, the device for adjusting the height of the laminating roller is configured to bring the laminating roller from a storage position to a laminating position on the top side of the master element. This height adjustment preferably comprises a translation of the laminating roller on an extension of at least 1 cm, preferably at least 5 cm, more preferably at least 10 cm. Suitable devices for this height adjustment are well known to those skilled in the art. Therefore, before or after lamination, the laminating roller can be brought outside the area between the master element and / or the input coupling element and / or the light source. This allows greater freedom in applying the input coupling element and / or exposing the master element.

[0104] In another preferred embodiment of the invention, the device for adjusting the height of the laminating module is also configured for adjusting the height of the laminating roller. Preferably, the device for adjusting the height of the laminating roller is configured to adjust the height of the laminating roller up to + / -50 μm, preferably + / -100 μm, particularly preferably + / -500 μm. The resolution of the height adjustment is preferably at least 50 μm, in particular at least 10 μm. The resolution of the height adjustment preferably relates to the minimum step length that the laminating roller can translate for height adjustment.

[0105] This height adjustment can advantageously compensate for very small changes in the surface position or surface quality of the master element. For example, the master element may position the first carrier device itself only within a tolerance range. Due to manufacturing tolerances, the actual height of the master element may also depend on the target height. These tolerances can therefore be compensated when positioning the laminating roller so that it is always applied to the surface of the master element with a predetermined pressure. If the first carrier device does not in any case have a tiltable design as explained above, a slightly tilted position of the first carrier device can also be compensated in this way. These measures improve the optical contact between the composite web and the master element while avoiding excessive lamination pressures.

[0106] In another preferred embodiment of the invention, the laminating roller is initially brought to a predetermined position on the surface of the master element and then the height is adjusted by a small displacement step. In this way, the laminating roller can be brought particularly accurately to the actual surface of the master element.

[0107] Preferably, the height adjustment of the laminating roller is pressure-regulated. For this purpose, one or more sensors, in particular compression force sensors, may be used. Preferably, a compression force sensor is used to determine that the pressure of the laminating roller when in contact with the surface of the master element is within a predetermined range. For example, the pressure sensor may be a membrane on the surface of the laminating roller.

[0108] In another preferred embodiment of the invention, the laminating roller is cushioned, the cushioning preferably being configured for a height tolerance of at least + / -50 μm, preferably + / -100 μm, particularly preferably + / -500 μm. Such a cushioning can compensate for tolerances in the surface quality of the master element and / or the relative positioning of the master element and the laminating roller. The cushioning can also eliminate air gaps and / or air bubbles between the master element and the laminating roller, thus improving the optical contact between the composite web and the master element.

[0109] The cushioning of the laminating roller is preferably carried out mechanically, (electro)magnetically, hydraulically or pneumatically, wherein pneumatic cushioning is particularly preferred. Preferably, the cushioning of the laminating roller is pressure-regulated, in particular in order to establish and maintain a preferred pressure between the laminating roller and the master element.

[0110] In another preferred embodiment of the invention, the first carrier and / or the second carrier comprises one or more sensors for determining contact with another process component. Preferably, a compression force sensor is used to determine that the first carrier is in contact with the laminating roller and / or with the second carrier with sufficient pressure.

[0111] It may be preferred that an optical fluid is applied to the horizontal surface of the master element and / or the composite web before exposure. Preferably, the apparatus comprises means for applying such an optical fluid. The refractive index of the optical fluid may be close to the refractive index of the substrate of the master element, the input coupling element and / or the composite web, in order to ensure an undisturbed transmission of light. Furthermore, the optical fluid may improve the optical contact between the elements, since possible wedge errors, surface tolerances or damages are compensated. Likewise, air gaps or gas bubbles between process components may be filled, in order to suppress unfavorable reflections at the interfaces between the components.

[0112] In another preferred embodiment of the invention, a dosing unit for dosing the optical fluid is provided. The dosing unit is preferably configured to apply a predetermined amount of the optical fluid to the process component. In particular, the dosing unit is preferably configured to apply to the composite web an amount of the optical fluid sufficient to completely fill the gap between the input coupling element and the composite web.

[0113] In another preferred embodiment of the invention, the dosing unit is mounted in a height-adjustable manner. Thus, the dosing unit can be brought close to the surface of a process component (e.g. a composite web) for precise application of the optical fluid and can then be removed to make room for further process components (e.g. an input coupling element or a light source).

[0114] In another preferred embodiment of the present invention, an optical fluid is introduced between the composite web and the input coupling element. The amount of optical fluid used is preferably configured to cover the contact surface between the input coupling element and the composite web. Preferably, the optical fluid adheres to the surfaces of the input coupling element and the composite web by means of capillary forces. The larger the contact surface between the input coupling element and the composite web, the greater the force generated. This helps maintain optical contact during the movement of the input coupling element over the composite web.

[0115] Preferably, the in-coupling element is removed from the composite web after exposure so that adhesion forces on the composite web are minimized.

[0116] In a preferred embodiment of the invention, the input coupling element is moved horizontally in the plane of the composite web (preferably transversely to the direction of travel of the composite web) before the input coupling element is removed from the composite web by vertical movement. This movement in the plane of the composite web may be a transverse, tilting or rotational movement. The movement is preferably configured to reduce the contact surface between the input coupling element and the composite web without implementing a vertical movement. This can effectively avoid the transmission of unfavorable forces to the composite web. When using an input coupling element with a curved contact surface (for example when using a cylindrical input coupling element), the input coupling element can be removed preferably without such a movement, because the narrower contact surface reduces the risk of deformation or distortion of the composite web.

[0117] In another preferred embodiment of the invention, an optical adhesive film is temporarily introduced between two process components of the apparatus or system before exposure. Preferably, the apparatus comprises means for applying such an optical adhesive film. For example, the optical adhesive film can be introduced between the master element and the composite web and / or between the composite web and the input coupling element.

[0118] Within the meaning of the present invention, an "optical adhesive film" is preferably a transparent film having a refractive index close to that of the master element, the composite web and / or the input coupling element. The optical adhesive film is preferably configured to improve the optical contact between the two exposed process parts, so that reflections at the interface between the process parts are reduced or eliminated.

[0119] Preferably, the material used for the optical adhesive film has the same or similar optical properties as the material used for the substrate of the master element (or the substrate of the input coupling element or its input coupling section) and / or the composite web. Preferably, similar or identical properties include transparency, haze, stress birefringence properties and / or refractive index. Using the same or similar materials allows the refractive index of the optical adhesive film to be very closely matched to the refractive index of the adjacent process components, thus ensuring that there is no refractive index jump in the transition between adjacent refractive indices. This largely eliminates or significantly reduces reflections at the interface between the master element (or input coupling element), the optical adhesive film and / or the photosensitive composite web.

[0120] In a preferred embodiment of the present invention, the difference in refractive index between the surface of the master element (or cover) and the optical adhesive film and / or between the optical adhesive film and the surface of the photosensitive composite web is not greater than 0.2, preferably not greater than 0.1, more preferably not greater than 0.05. Likewise, in the case where the optical adhesive film is introduced between the photosensitive composite web and the input coupling element, the difference between the refractive index of the optical adhesive film and the refractive index of the adjacent surface of the input coupling element is preferably not greater than 0.2, more preferably not greater than 0.1, more preferably not greater than 0.05.

[0121] In another preferred embodiment of the invention, the refractive index of the optical adhesive film is between the refractive index of the surface of the master element and the refractive index of the surface of the photosensitive composite web. If the optical adhesive film is arranged between the photosensitive composite web and the input coupling element, the refractive index of the optical adhesive film is preferably between the refractive index of the photosensitive composite web and the refractive index of the input coupling element. In this context, the term "between" preferably also encompasses the refractive index values ​​of the adjacent process components themselves. This arrangement allows a smooth or undisturbed transition of the light beam between different process components with minimal reflections and / or aberrations at the interface.

[0122] In addition, the "optical adhesive film" is preferably a solid in which the Brownian motion of the molecules is sufficiently small, thereby preventing "wobbling" of the light phase; therefore, this produces a more stable interference field in the hologram copy during the exposure time. In this way, the microstructures do not get dirty, whereby the diffraction efficiency of the hologram is maximized. The clarity and contrast of the resulting hologram are also substantially improved. The optical adhesive film improves the optical contact between the exposed transparent parts through which the exposure light is directed. This reduces unfavorable reflections, scattering or losses, and the quality of the reproduced hologram is improved.

[0123] The optical adhesive film can be formed in a similar manner to the composite web and can be moved through the process in a similar manner, for example by means of rollers. This enables simple synchronization of the optical adhesive film and the composite web. It is also possible and may be preferred that the optical adhesive film and / or the photosensitive composite web is applied to the surface of the master element or to the surface of the input coupling element by means of a laminating roller. In this case, the same roller can be used to laminate the composite web and the optical adhesive film.

[0124] In addition to having favorable optical properties, the optical adhesive film preferably has a lower adhesive force than OCAs (Optically Clear Adhesives) known from the field of optical displays. Thus, after use, the optical adhesive film can be easily removed from the surface without residue.

[0125] In a preferred embodiment of the present invention, the optical adhesive film comprises at least one adhesive layer. The at least one adhesive layer preferably has a peel force of less than 3 N / cm (Newtons per centimeter), preferably less than 1 N / cm, relative to the surface of the master element and / or the surface of the input coupling element and / or the surface of the photosensitive composite web. However, in a preferred embodiment, the peel force of the adhesive layer of the optical adhesive film relative to the surface of the master element and / or the surface of the input coupling element and / or the surface of the photosensitive composite web is at least 0.01 N / cm, preferably at least 0.1 N / cm. For example, the peel force of the optical adhesive film or one of its layers can be measured according to a 180 degree peel test. In a preferred embodiment, the measurement is implemented according to ASTM D903.

[0126] In a preferred embodiment of the present invention, the optical adhesive film has a single-layer structure, wherein the layer structure comprises exactly one adhesive layer. The exactly one adhesive layer is preferably adhesive on both sides in order to achieve optical contact.

[0127] In a preferred embodiment of the invention, the optical adhesive film comprises two adhesive layers, wherein each adhesive layer is preferably applied directly to a carrier layer, so that the optical adhesive film comprises three layers. Such an optical adhesive film can be adhered to two surfaces at the same time, whereby particularly good optical contact can be achieved and the risk of air gaps or unfavorable reflections is reduced.

[0128] In a preferred embodiment, the apparatus comprises an unwinding roller for unwinding the optical adhesive film and a take-up roller for winding up the optical adhesive film after use. Preferably, the method (preferably controlled by a control unit) comprises a step of removing the optical adhesive film from the relevant process parts after exposure. Preferably, the apparatus further comprises a laminating roller for temporarily laminating the optical adhesive film onto the surface of the master element, the composite web and / or the input coupling element. Preferably, the optical adhesive film may be provided with a protective layer on one or both sides. The apparatus may comprise a take-up roller for removing the protective layer before using the optical adhesive film.

[0129] In a preferred embodiment of the invention, the first carrier device is configured to arrange the master elements in two parallel rows. By using at least two rows, the size of the master elements can be further reduced while at the same time the entire width of the composite web can be utilized in an optimal manner. If changes are required for partial areas of a larger master hologram to be replicated, these changes can also be implemented in smaller portions. Furthermore, the efficiency of the method can be increased, since a greater number of identical or different master holograms can be replicated simultaneously.

[0130] With sufficient luminous intensity, two rows can be exposed from the optically accessible side of the master element. That is, a light beam directed into the side of a master element in the first row can reach a master element in the second row that is located behind said master element in the first row in the direction of the light beam. This further increases the efficiency of the process, since two master holograms can be replicated simultaneously by one light source.

[0131] Likewise, it may be preferred to expose each row separately, for example using separate light sources directed to two opposite sides of the arrangement of master elements. Preferably, the rows of master elements are separated by light absorbing spacers, wherein the spacers are preferably part of the first carrier means. The light absorbing spacers prevent undesirable light from one master element from penetrating into another master element, thus avoiding optical interferences such as crosstalk. It is particularly advantageous if master elements in different rows should be exposed from different angles or using different wavelengths.

[0132] In a preferred embodiment of the present invention, the exposure module comprises a light source.

[0133] In a preferred embodiment of the invention, the light source emits a coherent light beam. Coherence preferably refers to the property of a light wave whereby a fixed phase relationship exists between two wave trains. Due to the fixed phase relationship between the two wave trains, a spatially stable interference pattern can be generated. With regard to coherence, a distinction can be made between temporal coherence and spatial coherence. Spatial coherence preferably exhibits a measure of the fixed phase relationship between the wave trains perpendicular to the propagation direction and is given, for example, for parallel light beams. Temporal coherence preferably exhibits a fixed phase relationship between the wave trains along the propagation direction and is given in particular for narrow-band, preferably monochromatic light beams.

[0134] The coherence length preferably denotes the maximum path length difference or flight time difference that two light beams from a starting point have such that during their superposition a (spatially and temporally) stable interference pattern is generated. The coherence time preferably refers to the time required for light to travel the coherence length.

[0135] In a preferred embodiment, the light source comprises a laser. Particularly preferably, the light source is a narrow-band, preferably monochromatic laser, with a preferred wavelength in the visible range (preferably 400nm to 780nm). Non-limiting examples include solid-state lasers (preferably semiconductor lasers or laser diodes), gas lasers, or dye lasers.

[0136] Other light sources, preferably coherent light sources, may also be used.Preferred are narrow-band light sources, preferably monochromatic light sources, for example comprising light emitting diodes (LEDs), optionally in combination with a monochromator.

[0137] For replication at different wavelengths, it may be preferred, for example, to provide illuminating radiation in different wavelength ranges, for example the red wavelength range (preferably 630 nm to 700 nm), the green wavelength range (preferably 500 nm to 560 nm) and / or the blue wavelength range (preferably 450 nm to 475 nm).

[0138] For example, a laser system with three monochromatic lasers or a multicolor laser with laser emission in the red, green or blue (RGB) range can be provided for this purpose. It can also be preferred that the light source comprises a white light laser and a tunable wavelength filter configured such that the wavelength used for exposing the composite web can be set.

[0139] The exposure module may also include one or more motors configured so that they set the angle of the light source and / or move the light source along a trajectory. For example, the light source may be configured as a scanning light source. The light source may also be provided with an axis along which the light source can slide. The exposure module may also include one or more reflectors, the positions of which may also be adjustable so as to divert the path of the light beam to the master element and / or the composite coil. The exposure module may also include one or more lenses, such as divergent lenses, so as to widen the light beam on the master element. It may also be advantageous that the exposure module is equipped with a device for setting the light intensity incident from the light source to the master element and / or the composite coil.

[0140] The exposure to replicate the master hologram by means of the device according to the invention can be carried out based on different techniques.Hologram replication methods can be divided into relief holograms and volume holograms.

[0141] The relief hologram is formed by physical contact between the deformable sensitive layer and the master hologram so that the diffraction pattern of the master hologram is imprinted in the sensitive layer.

[0142] The volume hologram is preferably written into the sensitive layer by interference of two light beams, a so-called reference beam and an object beam. Preferably, the volume hologram is written into a composite web. Preferably, this can be implemented by transmission or reflection techniques. Due to the interference of the object beam and the reference beam within the hologram volume, a series of Bragg planes are preferably generated. Therefore, the volume hologram preferably has a non-negligible range in the propagation direction of the light beams, wherein the Bragg conditions apply in the case of reconstruction at the volume hologram. It is for this reason that the volume hologram has wavelength selectivity and / or angle selectivity. The ability of a volume hologram to store multiple images simultaneously allows in particular the generation of color holograms. Light sources emitting the three primary colors of blue, green and red can be used to record the hologram. Preferably, the three light beams illuminate a portion of the composite web at the same angle simultaneously. After exposure, the three holograms are stored simultaneously in the volume hologram. The reproduction of the color hologram can make use of the fact that each partial hologram can only be reconstructed by the color used to record it. Therefore, if the color components are correctly weighted, the three reconstructed color areas can be superimposed to form a realistic color image.

[0143] A reflection hologram is a reflection hologram that reflects light incident from a light source and thus works like a mirror. The directions of incidence of the reference beam (preferably the beam incident from the light source) and the object (in this case the master hologram) are preferably arranged on opposite sides of the composite web. The reference beam passes through the composite web and is then reflected by the master hologram back into the photosensitive layer of the composite web. Thus, the reference beam and the object beam are superimposed in the photosensitive layer of the composite web in different beam directions in order to produce a replicated hologram. Preferably, the master hologram can be applied to the surface of the master element or be present in a manner integrated in the substrate body.

[0144] The light source for reflecting the hologram can be arranged so that the reference beam is incident on the composite web in a desired direction, preferably in a direction desired in a subsequent reconstruction process. In a preferred embodiment, the light source is oriented relative to the master element in such a way that the composite web is located between the light source and the master element. For example, the light source can be aligned above the master element in such a way that the reference beam is incident on the composite web downwardly in a predetermined direction. Preferably, at least a portion of the reference beam is reflected by the master element back into the composite web as an object beam. Thus, the reference beam and the object beam enter the photopolymer composite from opposite sides and interfere in the photosensitive layer of the photopolymer composite in order to replicate the hologram.

[0145] A transmission hologram is a transmissive hologram in which light from a light source passes through the transmission hologram and is diffracted by it. The incident directions of the reference beam (preferably the incident beam from the light source) and the object (in this case the master hologram) can preferably be present in such a way that they are arranged on the same side of the composite web. The incident beam passes through the master hologram and is split into a (undiffracted) reference beam and an object beam. The reference beam and the object beam are thus superimposed in the photosensitive layer of the composite web with the same beam direction in order to produce a replicated hologram.

[0146] In a transmission hologram, it may be preferred to arrange the light source in such a way that the composite web can be exposed from the same side by the reference beam and the object beam. Preferably, the light source is oriented relative to the master element in such a way that the light beam first passes through the master element and the master hologram and then reaches the composite web. Preferably, the light source may be arranged in such a way that the light passes through the transparent master element from the side. Preferably, the light source may also be arranged in such a way that the light is incident on the composite web through the upper and / or lower surface of the master element. Preferably, the incident light beam is refracted by the master element in such a way that a reference beam and an object beam are generated, wherein the object beam preferably corresponds to the component of the light diffracted by the master hologram. Preferably, the object beam interferes with the undiffracted reference beam in the composite web in order to replicate the hologram.

[0147] In a preferred embodiment of the invention, one or more master elements may be used to expose a composite web so that a transmission hologram is replicated therein. Preferably, the replicated transmission hologram may be designed to be edge-illuminated, so that the holographic image representation can be reconstructed by light from a substantially lateral direction. The replicated transmission hologram may also be configured so that it is illuminated from behind, so that the holographic image representation can be reconstructed by light incident in a substantially back-to-front manner. It may also be preferred to use one or more master elements to expose a composite web and replicate a reflection hologram therein. It may also be desirable that the replicated reflection hologram is edge-illuminated. For example, such a hologram may be used in a glass sheet, with the light source being arranged in a hidden manner at the edge of the glass sheet. The replicated reflection hologram may also be configured so that it is illuminated from the front. Advantageously, such a hologram may produce a holographic image representation when illuminated by ambient light and viewed relatively orthogonally at eye height. A plurality of such holograms may also be used in a glass sheet, for example in a manner as disclosed in WO2020157312A1, to produce a holographic image representation when viewed orthogonally by reflection of light from a hidden light source along a predetermined path. It may also be advantageous to use one or more master elements to expose the composite web in order to produce a hologram comprising both a reflection hologram and a transmission hologram.

[0148] In a preferred embodiment of the invention, the reference beam may be directed to the side of the master element for the purpose of exposing the hologram. In other preferred embodiments of the invention, it may be preferred that, in addition or in the alternative, the reference beam is directed to the upper and / or lower horizontal plane of the master element.

[0149] Different techniques for exposing composite webs and master elements using different reference beam angles and for producing different types of holograms are explained in the detailed description based on the drawings. It should be noted that these techniques can optionally be combined with each other and with various structural arrangements of the apparatus. An important advantage of the invention is that, preferably, multiple types of exposure can be performed in the same apparatus and during the same iterative process.

[0150] In a preferred embodiment of the invention, the separation module comprises a separation roller, which is positioned below the height position of the composite web. Preferably, the separation module comprises an actuator for moving the separation roller along a path after exposure. Preferably, the path comprises an elevation of the separation module, so that the composite web located above it is also elevated.

[0151] In another preferred embodiment of the present invention, the first carrying device is configured to carry at least two, preferably at least three, more preferably at least four master elements.

[0152] In a preferred embodiment of the invention, the apparatus further comprises a fixing module. This ensures that the apparatus is more compact and improves the quality of the final product, since fixing can be performed immediately before optical or mechanical interferences damage the just exposed composite web.

[0153] In another preferred embodiment of the invention, the device comprises a control unit. Preferably, the control unit comprises a processor and a memory. The processor is preferably configured to control the selection and optional arrangement of a sequence of master elements, wherein the processor reads the sequence data from the memory and sends a signal to the actuator and / or the user about the sequence in which the master elements should be arranged.

[0154] Thus, the control unit may preferably ensure that the master holograms are arranged in the first carrier device according to a predetermined sequence, for example an sequence to be followed when processing relatively large components with integrated replicated holograms on a parallel production line.

[0155] Preferably, the term "control unit" relates to any desired computer unit with a processor, processor chip, microprocessor or microcontroller, which allows automatic control of components of the device, such as the rotation speed of unwinding rollers, winding rollers, laminating rollers, conveyor rollers, a pick-and-place robot for master elements, an alignment unit for master elements or the movement of a carrier, lamination temperature, lamination pressure, orientation and / or scanning speed of the light source, wavelength of the light source, fixing intensity, etc. The components of the control unit may be conventionally configured or may be individually configured for the respective embodiment. Preferably, the control unit comprises a processor, a memory and a computer code (software / firmware) for controlling the components of the device.

[0156] The control unit may also include a programmable printed circuit board, a microcontroller or any other device for receiving and processing data signals from components of the device (e.g., from sensors related to the identity or type of the motherboard element), and other related sensor-based information. The control unit preferably further includes a computer-usable or computer-readable medium, such as a hard disk, random access memory (RAM), read-only memory (ROM), flash memory, etc., on which computer software or code is installed. The computer code or software for controlling the components of the device can be written in any desired programming language or model-based development environment, such as C / C++, C#, Objective-C, Java, Basic / VisualBasic, MATLAB, Python, Simulink, StateFlow, Lab View or assembler, but is not limited thereto.

[0157] The phrase "the control unit is configured to" perform specific method steps, for example, exposing the master element at a specific angle by varying the speed of one or more drive motors, may include customer-specific software or standard software installed on the control unit and initiating and controlling these operating steps.

[0158] In another preferred embodiment of the present invention, the exposure instructions of the sequence are stored in a memory. Preferably, the processor sends a signal to the user and / or the actuator according to the exposure instructions to set the position, path and / or wavelength of the light source. Preferably, the control unit includes an interface for sending a signal about the exposure instruction to the user.

[0159] In a preferred embodiment of the invention, the control unit is connected to a sensor, which preferably reads an ID feature of the individual master elements or of their storage locations and transmits this ID to the control unit for controlling and / or monitoring the sequential arrangement.

[0160] Within the meaning of the present invention, an "ID feature" preferably relates to the entire master hologram itself or a part thereof, or alternatively to a QR code, a barcode, a number, a symbol or the like, which can be permanently or removably fixed to a master element for identifying the master element. In addition or in an alternative, the ID feature may not be located on the master element, but rather on its storage location. Preferably, the ID feature is fixed to an area of ​​the master element that does not intersect the path of the light beam used for exposure. Preferably, this area is located on a surface of the master element that is different from the at least two optically accessible surfaces.

[0161] By controlling or monitoring the identification of the master elements placed in the first carrier device and exposed, the control unit is able to prevent and / or identify errors in the sequence. Preferably, the control unit is also able to draw the attention of a user to such errors so that corrective interventions can be made during the production process. Another advantage is that a register of the exposed holograms can be created and stored in a memory. This register can be used for quality control and statistical purposes. The control unit can also use this information to determine which master elements require maintenance or replacement. Thus, for example, depending on the number of uses (optionally weighted by the exposure intensity), the corresponding master element can be replaced before its degradation leads to a loss of quality.

[0162] In another aspect, the invention relates to a system for replicating a plurality of holograms, the system comprising the above-described apparatus and a plurality of master elements, the master elements comprising a substrate body and at least one master hologram, wherein a series of master elements can be selected from the plurality of master elements based on the plurality of holograms to be replicated.

[0163] In another preferred embodiment of the invention, the first carrier is designed so that master elements of different shapes and / or sizes can be arranged therein. Thus, for example, one or more frame elements and / or spacers of the carrier can be arranged in a displaceable and / or clampable manner. The first carrier can also be designed so that it can accommodate master elements of different thicknesses. A filling substrate block can be fixed below one or more master elements so that the top sides of the master elements are at the same height.

[0164] In another preferred embodiment of the invention, the base bodies of the master elements have the same size. Preferably, these base bodies have a parallelepiped shape. It has been found that the use of identical square-shaped master elements allows a particularly simple alignment of the master elements in the first carrier device. However, the use of different shapes is also possible, in particular shapes or dimensions that vary along the film web. Different shapes of the base of the master elements are also possible perpendicular to the film web; however, this is less preferred in view of the less material used.

[0165] In another preferred embodiment of the present invention, preferably, the height of the substrate is between 1 cm and 10 cm, the length is between 3 cm and 20 cm, and the width is between 3 cm and 20 cm.

[0166] Although the system can include a master element of any desired size in principle, it is found that a height of at least 1 cm is preferred so that there is enough exposure area on the side of the master element. In addition, the preferred height is also convenient for exposure from different angles to meet the different requirements of hologram replication. In addition, the preferred size ensures sufficient robustness under a compact size to allow simple replacement. In addition, the length and / or width specified as at least 3 cm preferably allow the full economic utilization of the composite coil, especially when there is a buffer interval between the master element. In addition, these dimensions are suitable for capturing images or patterns to be copied for applications such as printing banknotes. Even if the length and / or width of the substrate body are equally unrestricted, a substrate body of up to 20 cm in length and / or width allows for reduced production costs and allows for particularly easy handling.

[0167] In another preferred embodiment of the invention, at least two optically accessible faces of the master element are polished, wherein the polishing level is preferably at least P3. In another preferred embodiment of the invention, the optically accessible faces of the input coupling element are also polished, wherein the polishing level is preferably also at least P3. Preferably, the optically accessible faces are provided with an anti-reflection coating.

[0168] Advantageously, if the surface of the input coupling element bears against the surface of the master element via the composite web, both surfaces are polished. Furthermore, it is also preferred that the wedge errors of the master element and / or the input coupling element itself and of each other are substantially reduced. In the case of an unfavorable wedge, planar optical contact may be impaired due to a parallel displacement of the input coupling element relative to the master element.

[0169] In another preferred embodiment of the present invention, the substrate body of the master element is formed of a material that is an optical plastic. Preferably, the material of the substrate body is selected from the following group: polymethyl methacrylate (PMMA), polycarbonate (PC), cycloolefin polymer (COP), cycloolefin copolymer (COC), and / or optical glass, preferably selected from the following group: borosilicate glass, quartz glass, B270, N-BK7, N-SF2, P-SF68, P-SK57Q1, P-SK58A and / or P-BK7.

[0170] Preferably, the refractive index of the base body and of any cover element of the master element is between 1.4 and 1.6.

[0171] The choice of material for the substrate body may depend on the desired exposure angle, possible height restrictions and the desired refractive index resulting therefrom. It may also be preferred that the substrate body is colored in order to filter the light, for example based on wavelength selection, so as to produce a hologram with a specific wavelength. In this way, a broadband light source may be used to expose different master holograms.

[0172] In a preferred embodiment of the invention, the master elements are separated along a linear arrangement in the first carrier. Therefore, the carrier can preferably form a buffer interval between adjacent master elements. The buffer interval advantageously prevents unfavorable propagation or scattering of light from one master element to an adjacent master element, thereby avoiding damage to the copied hologram. At the same time, the interval can be beneficial for handling the copied hologram. Firstly, the corresponding hologram can be separated more easily. Secondly, even after cutting and separation, a small edge will remain around the hologram, which allows the hologram to be transported without contact with the image content. The risk of damage to the fully copied hologram is reduced and the quality is improved.

[0173] Preferably, the master elements are separated by light-absorbing spacers. This protects the master hologram and the portion of the composite web on which it is located from stray light or light used to expose adjacent master holograms. If unfavorable light reaches the wrong area of ​​the composite web, the composite web may be exposed to unfavorable patterns, which may be superimposed on the reproduced image, reducing the image quality. Assuming that the light is directed to the side of the first master element in the absence of a light-absorbing barrier to expose the first master element, the light may, for example, reach a second master element arranged in a row adjacent to the first master element. In this way, the second master element may be exposed from an inappropriate angle, thereby producing an unintended ghost image on the relevant portion of the composite web. This phenomenon is called "crosstalk" and is particularly effectively prevented by using light-absorbing spacers.

[0174] Furthermore, the integration of light-absorbing spacers in the carrier allows the outwardly directed sides and the top side of the master element to remain optically accessible. In addition, the base body of the master element can advantageously remain completely transparent on all sides. This is particularly advantageous for configurations that allow exposure from different orientations (e.g., transmission or reflection), optionally with edge lighting or back lighting.

[0175] Alternatively or additionally, it may be preferred to apply a light absorbing layer to the vertical faces of the master element. The light absorbing layer may be much thinner than the spacers of the carrier device. Thus, multiple master elements can be exposed adjacent to each other without optical interference, while maintaining a minimal buffer spacing or a nearly continuous effect in the replicated holograms composed of multiple components from the various master holograms.

[0176] Advantageously, this enables almost seamless replication of large-sized (overall) holograms with high image quality without the need to use master elements of the same size. In addition, small changes can be made to a portion of the hologram without having to replace all master elements. For example, the area of ​​the (overall) hologram to be replicated that should be modified between iterations may relate to the (local) language of the text elements used in the head-up display in the car. In another example, the required arrangement or alignment of the master elements may also vary depending on whether the head-up display is for a left-hand drive vehicle or a right-hand drive vehicle of the same model. By utilizing the principle of typesetting, in which independent master elements can be replaced accordingly in a simple manner, the method and device enable such adaptation to be implemented quickly and cost-effectively.

[0177] Preferably, the thickness of the light-absorbing layer is at most 5 mm, preferably at most 3 mm, more preferably at most 1 mm, and / or preferably at least 10 μm, preferably at least 100 μm, particularly preferably at least 500 μm.

[0178] Preferably, the device and / or system according to the present invention is configured to perform a method for replicating a plurality of holograms. The method preferably comprises the following steps:

[0179] a. Providing a plurality of master elements, each master element comprising a substrate body and at least one master hologram,

[0180] b. selecting a series of master elements from a plurality of master elements based on a plurality of holograms to be replicated, and arranging the series of master elements on a first carrier so that the upper surfaces of the master elements are aligned in a horizontal plane,

[0181] c. removably laminating the photosensitive composite web to the aligned face of the master element,

[0182] d. exposing the master element to replicate the master hologram into a web of photosensitive composite material, and

[0183] e. Separating the exposed composite web from the master element,

[0184] wherein the master element is detachably incorporated in the first carrier device such that the sequence and / or composition of the master element for replicating a plurality of holograms is variable, and wherein the master element is incorporated in the first carrier device such that two or more faces of the master element are optically accessible for exposure.

[0185] A person skilled in the art realizes that the technical features, definitions and advantages of the preferred embodiments of the apparatus of the present invention also apply to the method, and vice versa.

[0186] The method steps can be programmed in the control unit.

[0187] In a preferred embodiment of the method, the selection and optionally the arrangement of the sequence of master elements is controlled by a control unit.

[0188] Preferably, the control unit comprises a processor and a memory. Preferably, the processor reads the sequence data from the memory and sends a signal to the actuator and / or the user regarding the sequence in which the master elements should be arranged. Thus, the control unit can preferably ensure that the master holograms are arranged in the first carrier according to a predetermined sequence, such as the sequence followed when processing relatively large components with integrated replicated holograms on a parallel production line.

[0189] It may be advantageous that the control unit instructs the actuator to move the next master element or the next n master elements in the sequence closer to or into the first carrier, wherein n is preferably the number of master elements that the first carrier can accommodate. Preferably, the actuator may be a logistics trolley, any other conveyor belt, a rotary table or a pick-and-place robot, to name a few. In this way, placing the master elements in the correct sequence may be partially or fully automated, thereby reducing the risk of human error.

[0190] It may also be preferred that the control unit is configured to signal the user about the next master element or the next n master elements. This may be implemented in different ways, for example visually or acoustically. As an example of a visual signal, the control unit may be configured to activate a light at the storage location of the next master element (e.g. at a corresponding shelf, box, trolley, etc.).

[0191] Preferably, the control unit comprises an interface for sending a signal about the sequence to the user. Thus, the processor may be configured to read the sequence data from the memory and instruct the interface (e.g., monitor) to display all of the sequence data or a relevant portion thereof. Preferably, the sequence data may include information about:

[0192] - the identification or type of master elements to be exposed and their sequence,

[0193] - a matrix arrangement of the master elements in the first carrier device, for example row or column numbering,

[0194] - one or more wavelengths intended for exposing the master element,

[0195] - the luminous intensity intended to be used to expose the master element,

[0196] - the angle at which the master element is intended to be exposed, and / or the angular position and path of the light source,

[0197] - The type of hologram to be produced, e.g. reflection hologram or transmission hologram.

[0198] This list is neither exhaustive nor exclusive but merely exemplary. DETAILED DESCRIPTION

[0199] In the following, the invention will be explained in more detail with the aid of examples and drawings, but without being restricted thereto. BRIEF DESCRIPTION OF THE DRAWINGS

[0200] Figure 1 is a schematic diagram of a preferred embodiment of the apparatus according to the invention.

[0201] Figure 2 is a schematic diagram of another preferred embodiment of the device according to the invention, in which an input coupling element is used.

[0202] Figure 3 is a schematic diagram of a preferred embodiment of a device according to the invention, wherein a light absorbing spacer separates the master element and the input coupling element.

[0203] Figure 4 is a schematic plan view showing the replacement of the master element in the first carrier device.

[0204] Figure 5 is a schematic plan view of master elements arranged in two rows in a first carrier device.

[0205] 6 is a schematic side view of a preferred embodiment of an apparatus according to the present invention at different stages: A) before lamination, B) during lamination, C) during exposure, D) after exposure, E) during separation, and F) after separation.

[0206] Figure 7 is a schematic front view of the edge-illuminated reflection hologram reconstruction.

[0207] Figure 8 is a schematic front view of the edge-illuminated transmission hologram reconstruction.

[0208] Fig. 9 is a schematic elevational view of an exposure process for replicating an edge-illuminated reflection hologram by means of an in-coupling element.

[0209] Fig.10 is a schematic elevational view of an exposure process for replicating an edge-illuminated transmission hologram by means of an incoupling element.

[0210] Fig.11 is a schematic elevational view of an exposure process for exposing from above to replicate a reflection hologram.

[0211] Fig.12 is a schematic elevation view of an exposure process for replicating a multiple hologram including a reflection hologram and an edge-illuminated transmission hologram.

[0212] Fig.13 is a schematic front view of the exposure process for exposing a transmission hologram from below.

[0213] Fig.14 is a schematic elevation view of an exposure process for replicating multiple holograms including a transmission hologram and an edge-illuminated reflection hologram.

[0214] Fig.15 is a schematic elevation view of an exposure process for simultaneously exposing edge-illuminated transmission holograms from both sides of a first carrier having two rows of master elements.

[0215] FIG. 16A to FIG. 16F The use of a wedge-shaped input coupling element with an optical fluid is shown by way of example.

[0216] FIG. 17A to FIG. 17F The use of a cylindrical input coupling element with an optical fluid is shown by way of example.

[0217] Detailed description of the drawings

[0218] Figure 1 A schematic diagram of a preferred embodiment of an apparatus 1 according to the invention is shown. For the sake of simplicity, the exposure module and the separation module are not shown. The figure schematically shows a first carrier 10, which holds a linear arrangement of five master elements 2, so that the horizontal top sides of these elements are flush with each other and with the first carrier 10. A simple embodiment of the first carrier 10 is shown; it comprises only two end blocks, the position of which is preferably fixed, for example by being firmly clamped relative to each other or firmly clamped on a fixed surface. However, any desired embodiment of the first carrier 10 can be used, such as a frame connected along the underside of the master elements or an arrangement of cavities separated by rods, which are used to accommodate the master elements 2 so that at least two of their surfaces are optically accessible.

[0219] Preferably, the first carrier device 10 may, for example, comprise a frame element along the lower outer edge of the master element 2, said frame element covering no more than 50%, preferably up to 40%, 30%, 20%, 10% or less of the side surface of the master element 2. Within the meaning of the present invention, such a side surface is preferably regarded as an optically accessible surface. Figure 1In the embodiment of the present invention, the master element 2 has at least three optically accessible faces. F1 and F2 are optically accessible sides. F3 is the upper side and is only covered by the composite web 3. However, the composite web 3 is not a light absorbing material, so the upper side F3 can be regarded as optically accessible. The master hologram 6 in the master element 2 can be exposed by directing light to one or more of these optically accessible faces. The unwritten lower side of the master element 2 can also be optically accessible, especially when a first carrier device 10 with an appropriate frame structure is selected. Therefore, the bandwidth of angles at which exposure can be implemented is very large and suitable for very different exposure arrangements.

[0220] The composite web 3 is stretched over the top side of the master element 2 and the top side of the first carrier device 10. This arrangement is achieved by laminating the composite web 3 onto a flush surface with the aid of a laminating module. In this case, the laminating module comprises a laminating roller 7. For example, the laminating roller can be lowered onto the composite web 3 from the right-hand side in the figure, can be pressed onto the flush surface, and can be rolled onto the surface in a relatively movable manner. Figure 1 The position shown on the left in (see also 6A to 6F ). In order to avoid optical interference during the exposure process, the first carrier device 10 or the laminating roller 7 preferably comprises a light absorbing material or is preferably coated with an absorbing layer 5.

[0221] Figure 2 A schematic diagram of another embodiment of the device 1 according to the present invention is shown. The structure of this embodiment is similar to Figure 1 The embodiment shown is similar, with the main difference being the presence of input coupling elements 8 in a linear arrangement above the motherboard element 2 .

[0222] Even though the input coupling elements 8 can be placed manually on the master element 2, preferably the input coupling elements are carried by a second carrying device (not shown here), such as a frame. This allows for a precise and repeatable placement of the input coupling elements 8. In the embodiment shown, all input coupling elements 8 have the same size and the same shape, as do all master elements 2. The size and shape of the input coupling elements 8 are also identical to the size and shape of the master elements 2. Each input coupling element 8 corresponds to a single master element 2 and is placed directly above it, so that the sides of the input coupling element 8 are flush with the sides of the corresponding master element 2.

[0223] It is also preferred that at least two surfaces of each input coupling element 8 are optically accessible. In this embodiment, the input coupling element 8 is optically accessible from at least its side faces F4 and F5 and the top face (without reference numerals). The input coupling element 8 comprises a transparent block, which is preferably made of the same material as the base body 14 of the master element 2.

[0224] Figure 3 Another preferred embodiment of the device 1 according to the present invention is shown. The structure of the device 1 is similar to Figure 2 The structure of the device is similar to that of the first carrier device 10. The main difference is the use of light-absorbing spacers 4 between the master elements 2. In the figure, these light-absorbing spacers are shown in black. Even though their top side is not visible, the top side is flush with the top side of the first carrier device 10 and the top side of the master element 2. Figure 3 A row of light absorbing spacers 4 is also shown separating the input coupling elements 8 from each other, such that the underside of the spacers 4 is flush with the underside of the input coupling elements 8. Preferably, the spacers 4 are arranged between and in contact with the inner side faces of the master element 2 and the inner side faces of the input coupling elements 8. This preferably means that the spacers 4 are arranged along a face separating one master element 2 from an adjacent master element 2.

[0225] Figure 4 is a schematic plan view of a single row of first carrier means 10 comprising four master elements A to D. The figure shows a simple way in which the master elements 2 can be replaced based on the typesetting principle according to the invention. In this case, for example, master element C can be removed by, for example, horizontal displacement. Master element E can be inserted into the gap in the same way, for example by being pushed into a corresponding recess. The figure also shows the dimensions of the master elements 2 in an exemplary manner. The width of the master element 2 can be, for example, about 80 mm, while the length can be, for example, about 100 mm.

[0226] Figure 5 1 is a schematic plan view of two rows of first carriers 10 including eight master elements A to H. Figure 4 By using the same size of master elements 2 in two rows, the process can be accelerated, since more holograms can be produced per iteration. The size of the first carrier device 10 is adapted to accommodate a greater number of master elements 2 in two rows.

[0227] Fig. 6 is a schematic side view of a further embodiment of a device according to the invention for performing different method steps in a hologram replication process.

[0228] Fig. 6A The position of the various elements of the apparatus is shown immediately before the lamination step. Before the lamination starts, the master elements A, B, C, etc. are placed in a linear arrangement in a first carrier 10. In this case, the carrier 10 comprises only a single row. The number of master elements 2 arranged in a single row and their length determine the repeat length or "repeat pitch" 20.

[0229] Fig. 6AThe arrow on the laminating roller 7 indicates the vertical (upward / downward) movement of the laminating roller 7. In order to enable the composite web 3 to advance between iterations, the laminating roller 7 is advantageously located in a first position above the first carrier 10 and above the composite web 3, so that the movement of the composite web is not hindered by the friction between the laminating roller 7 and the composite web 3. It is also preferred that the laminating roller 7 is positioned to the side during the advancement of the composite web 3 in such a way that it is located outside the space between the input coupling element 8 and the master element 2. This enables the input coupling element 8 to move freely vertically in the space between it and the master element.

[0230] At the start of the lamination process, the lamination roller 7 is lowered to a second height so that it reaches the plane of the aligned horizontal surface of the master element 2 .

[0231] Also like Fig. 6A As shown, the input coupling element 8 of this embodiment comprises a lower input coupling section 9. In contrast to the rigid body of the input coupling element 8, the input coupling section 9 is composed of an elastic transparent material, such as silicone.

[0232] Figure 6B The positions of the various elements of the apparatus 1 during the lamination process are shown. The laminating roller 7, which captures the composite web 3 between it and the first carrier 10 and / or the master element 2, rolls horizontally in the upstream direction (to the left in the figure). This allows the upstream roll of the composite web 3 to be passively unwound. Lamination brings the composite web 3 into optical contact with the top side of the master element 2. The input coupling element 8, which is accommodated on the second carrier (not shown), can be lowered during the horizontal movement of the laminating roller 7. Preferably, the lowering speed of the input coupling element 8 and / or the rolling speed of the laminating roller 7 are matched to each other in order to ensure a rapid application of the input coupling element 8 without the risk of mutual obstruction.

[0233] Figure 6C The positions of the various elements of the device during the exposure process are shown. The input coupling element 8 is lowered to such an extent that the input coupling section 9 is in contact with the composite web 3 and is elastically pressed against the top side of the master element 2. In this way, the input coupling section 9 ensures a particularly uniform and gap-free optical contact between the master element 2, the composite web 3 and the input coupling element 8. The exposure module is not depicted in this figure, but the exposure module can be designed in different ways, including one or more light sources, reflectors, lenses, color filters, axes and / or motors.

[0234] Fig.6D The positions of the various elements of a preferred apparatus after an exposure procedure are shown. The input coupling element 8 starts to rise back to its first height. At the same time, the laminating roller 7 starts to roll horizontally downstream. Fig.10 An intermediate position of the input coupling element 8 and the laminating roller 7 during movement after exposure is shown.

[0235] Fig. 6E The device 1 is shown during a separation step in which the composite web 3 is separated from the top side of the master element 2. For this purpose, the laminating roller 7 is moved horizontally to the right. Preferably, a separation roller located in front of the master element 2 (not depicted here) can be raised upwards. The composite web 3 is arranged above the separation roller, so that the composite web is also raised as the separation roller is raised.

[0236] Fig. 6F The device 1 is shown after the separation step. The input coupling element 8 is fully raised to its first height and the composite web 3 has been separated from the master element 2. A sufficient distance remains between the raised composite web 3 and the master element 2 so that the master element can be removed, replaced or rearranged without contact with the composite web 3. In addition, at this stage, the laminating roller 7 can be raised back to its first height. Therefore, the composite web 3 is no longer clamped between the laminating roller 7 and the first carrier device 10. At this stage, the composite web 3 can be advanced to a subsequent workstation used in the method, for example to a fixing module. The advancement of the composite web 3 is preferably achieved by conveyor rollers (not depicted here).

[0237] The following figures illustrate different exemplary exposure techniques and types of holograms that can be produced using the method and apparatus 1 according to the present invention.

[0238] Figure 7 It is edge-lit reflective holographic Fig.13 Schematic front view of edge-illuminated reflection holography Fig.13 Located on the substrate 14 and captured under the cover 21. Reflection hologram Fig.13 , the substrate 14 and the cover 21 form the master element 2. The arrows indicate the Fig.13 During the reconstruction process, the reconstruction beam 19 is directed obliquely upwards to the side of the master element in such a way that the beam is reflected at a suitable angle to the reflection hologram. Fig.13 The light beam 19 is refracted by the transparent substrate 14 of the master element 2. The refracted light beam passes through the reflective hologram located in the master element 2. Fig.13 And reflected from the upper interface of the cover 21 back to the reflection hologram Fig.13 Reference numeral 15 schematically indicates the total internal reflection caused by the interface. These light beams that undergo total internal reflection are incident on the reflection hologram. Fig.13 The angle on the reflection hologram is decisive for the reconstruction of the reflection hologram. As shown by the dotted arrow, the light beam that undergoes total internal reflection is reflected by the reflection hologram. Fig.13 The holographic image thus produced is essentially the same as the holographic Fig.13The surface of the substrate 14 is perpendicular to the surface of the substrate, which is beneficial for readability if the hologram is placed on a vertical surface, for example. This type of illumination is called edge illumination, because the reconstruction beam is incident on the hologram or substrate body 14 essentially from the side.

[0239] Such holograms can be advantageously used in glass panels illuminated from the side edges, making the light source both compact and hidden. The holographic image is essentially only visible when the light source, such as an LED, is activated from the right angle, for example to display a warning symbol on the windshield.

[0240] Edge-lit Reflective Hologram Fig.13 Can be used as a master hologram. During the replication process, the master hologram and the photosensitive composite web must be exposed from the appropriate angle so that the replicated hologram can also produce a holographic image visible from the desired angle. As explained below, this can be implemented with the aid of embodiments of the device and method according to the present invention.

[0241] Figure 8 is a schematic front view of the reconstruction of an edge-illuminated transmission hologram 16. The edge-illuminated transmission hologram 16 is also located on the substrate body 14 and is captured under the cover 21. The transmission hologram 16, the substrate body 14 and the cover 21 form the master element 2. During the reconstruction process, the reconstruction light beam 19 is directed obliquely upward to the side of the master element 2 in such a way that the light beam is incident on the transmission hologram 16 at a suitable angle. The light beam 19 is refracted by the transparent substrate body 14 of the master element 2 and is incident on the transmission hologram 16 at this angle. When passing through the transmission hologram 16, the reconstruction light beam 19 is at least partially diffracted by the edge-illuminated transmission hologram 16 so as to produce a holographic image.

[0242] In this example, the light beam 12 used to form the holographic image is also substantially normal to the surface of the hologram. This can facilitate viewing depending on the position of the hologram relative to the user's eye height. This edge-illuminated transmission hologram 16 can also be used as a master hologram 6 in order to replicate the edge-illuminated transmission hologram 16 in the photosensitive composite web 3. To ensure the desired reconstruction angle, the master hologram 6 and the composite web 3 must be aligned at the same angle. Figure 8 The exposure is performed at exactly the same angle at which the reconstruction beam 19 is incident on the edge-illuminated transmission hologram 16.

[0243] Especially in Figure 7 and Figure 8In the case of an edge-illuminated hologram as shown in the example, the angle at which the reconstructed light must be incident on the replicated hologram in order to be correctly reflected and / or diffracted may be an acute angle. Direct exposure at such an acute angle may lead to mechanical challenges. The use of a substrate 14 increases the flexibility with which the light source can be positioned and moved for exposure. This is because the angle of incidence of the light on the master hologram 6 depends not only on the position of the light source, but also on the refraction caused by the substrate 14.

[0244] Fig. 9 is used to replicate edge-illuminated reflection holograms by means of the input coupling element 8 Fig.13 Schematic front view of the exposure process of FIG. 1. The reference beam 11 is directed obliquely downward to the side of the input coupling element 8 depicted as a block located above the master element 2. The reference beam 11 is refracted by the input coupling element 8, and the refracted reference beam 11 passes through the composite web 3 to the master hologram 6. The refraction caused by the input coupling element 8 helps to achieve the sharp angle of incidence required for edge-illuminated holograms. The master hologram 6 reflects the reference beam 11, causing the object beam 22 to pass from the master hologram 6 through the composite web 3 (with the master hologram 6). Figure 7 The object beam 22 and the reference beam 11 interfere with each other in the photosensitive material of the composite web 3 to produce a reflection hologram. The two beams are incident on the photosensitive material from different sides, so that the replicated hologram is a reflection hologram. Reference numeral 17 schematically indicates the two interfering beams.

[0245] The reconstructed beam 19 can be used to display a reflection hologram. Figure 7 As explained in detail in , the reconstruction beam 19 is reflected from the microstructure of the exposed photosensitive material in the direction of the dashed line with reference numeral 12 .

[0246] Fig.10 is a schematic front view of an exposure process for replicating an edge-illuminated transmission hologram 16 by means of an input coupling element 8. A reference beam 11 is incident upwards on the side of a master element in an oblique direction. The reference beam 11 is refracted by the substrate 14 of the master element 2 and the refracted beam is transmitted through the master hologram 6 and through the composite web 3. Part of the reference beam 11 is transmitted through the master hologram 6 undiffracted and part of the reference beam is diffracted to produce an object beam 22 which also passes through the composite web 3. Due to the optical contact between the input coupling element 8, the composite web 3 and the master element 2, there are essentially no interfaces between these elements with substantial changes in refractive index. Thus, undesirable reflections at the interfaces which could interfere with the exposure are avoided. This optical contact is also achieved by laminating the composite web 3 to the master element 2, by the optional use of an optical fluid and by a suitable choice of materials with similar refractive indices.

[0247] The diffracted object beam 22 interferes with the undiffracted transmitted reference beam 11 in the photosensitive material of the composite web 3 in order to write a transmission hologram. The two interfering beams are marked by reference numeral 17. Thus, in order to replicate a transmission hologram in the composite web 3, the two beams are incident on the photosensitive material from the same side or along the same beam direction. A reconstruction beam incident on the composite web from the same angle as the refracted reference beam 11 can be used to reconstruct the hologram. The reconstructed beam is schematically marked by a dashed arrow 12.

[0248] Fig.11 is a schematic front view of an exposure process for replicating a reflection hologram. In this embodiment, no input coupling element 8 is used. The top side of the master element 2 is optically accessible during the exposure process. The reference beam 11 is incident on the composite web 3 in an oblique downward manner and is refracted by the composite web 3 and / or the cover 21 so that the reference beam is transmitted to the master hologram 6 at a suitable angle. The master hologram 6 reflects the reference beam 11 to form an object beam 22, which passes through the composite web upward in the direction of the dashed arrow. Since the object beam 22 and the reference beam 11 are incident on the photosensitive material of the composite web 3 from different sides or in different beam directions, the replicated hologram is a reflection hologram.

[0249] Fig.12 is a schematic elevational view of an exposure process for replicating a multiple hologram comprising both a reflection hologram and an edge-illuminated transmission hologram as a master hologram 6. The transmission hologram is produced in the same manner as described above for Fig.10 To generate a reflection hologram, another reference beam 11 is directed at an angle onto the upper side of the input coupling element 8. The beam is refracted by the input coupling element 8 and transmitted through the composite web 3 onto the master hologram 6. The master hologram 6 reflects the reference beam 11 so as to generate an object beam 22, which is transmitted upward through the composite web 3.

[0250] The dot-dash arrow 22 shows the reflected object beam of the reflection hologram, which interferes with the reference beam 11 to produce a reflection hologram in the photosensitive material of the composite web 3. In contrast, the upward dashed arrow 22 shows the diffracted object beam of the transmission hologram, which interferes with the non-diffracted component of the reference beam 11 incident from obliquely below to produce an edge-illuminated transmission hologram 16 in the composite web 3.

[0251] In this arrangement, it may be advantageous to expose the transmission hologram and the reflection hologram separately. The input coupling element 8 may be in contact with the composite web 3 during exposure of the transmission hologram 16, while being removed during exposure of the reflection hologram. In this case, the reference beam 11 used to write the reflection hologram is not diffracted by the input coupling element 8, as indicated by the dashed arrow 11. This may be taken into account when setting the angle of the light source so that the desired reconstruction signal of the hologram can be generated.

[0252] Fig.13 1 is a schematic elevational view of an exposure process for exposing a transmission hologram 16 from below. In this example, one of the at least two optically accessible faces of the master element is the bottom face. The height of the master element 2 or substrate body 14 can advantageously be used to refract the light of the reference beam 11 and ensure the desired angle of incidence of the light. Thus, input coupling through the polished underside can be implemented.

[0253] Fig.14 It is used for replicating transmission holograms 18 and edge-illuminated reflection holograms. Fig.13 Schematic front view of the exposure process of multiple holograms. The transmission hologram 16 is replicated in the same manner as described above for Fig.13 The light source is aligned below the master element 2 in such a way that the reference beam 11 is directed obliquely upwards. Fig. 9 As explained, the reflection hologram is reproduced by the edge-illumination method with the aid of the incoupling element 8. Fig.13 In this embodiment, the angles of the reference beam 11 used to generate the transmission hologram and the reflection hologram are selected in such a way that the optical signals generated by reconstructing both holograms extend in the same direction, as indicated by the two types of dashed arrows.

[0254] Fig.15 is a schematic front view of an exposure process for simultaneously exposing two edge-illuminated transmission holograms 16 from both sides of a first carrier device 10 having two rows. In this example, the first carrier device 10 is configured such that it includes two rows of master elements 2. The two rows of master elements are separated by light-absorbing spacers 4. In addition, the input coupling elements 8 in the second carrier device are separated by similar light-absorbing spacers 4. The spacers 4 protect the buffer zone in the composite web 3 from the exposure. In addition, as shown in the figure, the composite web 3 can be exposed from two directions simultaneously. This increases the speed of the method. In this exemplary embodiment, the exposure method replicates the transmission holograms 16 on the two shown master elements 2 in the composite web 3. However, each master hologram 6 can be exposed from different angles and / or produce different types of holograms. Due to the light-absorbing spacers 4, the exposure of one master hologram 6 can be performed at different angles and / or produce different types of holograms. Due to the light-absorbing spacers 4, the exposure of one master hologram 6 can be performed at different angles and / or produce different types of holograms. Figure 2The reference beam 11 does not penetrate into adjacent holograms. This prevents interference such as "crosstalk" and improves the quality of the produced holograms.

[0255] FIG. 16A to FIG. 16F An embodiment of the invention is schematically shown, in which an input coupling element 8 is pushed over the surface of a composite web 3 by means of an optical fluid 29. In this embodiment, the input coupling element 8 is prismatic, and its cross section is a trapezoid, the shortest side of the trapezoid corresponding to the contact surface 30 designed for contact with the master element 2. Therefore, the shape of the input coupling element 8 can also be called a wedge shape.

[0256] Fig.16A The first stage of the method is shown. The master element 2 is arranged in a first carrier device 10 so that its surface is substantially flush. A composite web 3 is provided for replicating the master element. The composite web 3 is laminated onto the flush surface of the master element 2 by means of a laminating roller 7. To this end, the laminating roller 7 is brought from a storage position to the surface of the master element 2 so that the composite web 3 is located between the laminating roller 7 and the master element 2.

[0257] When the laminating roller 7 is positioned on the master element 2 before lamination, the laminating roller 7 can be moved, more specifically rolled, along a plane including the surface of the master element 2. Optionally, the laminating roller 7 also descends downward to the plane of the surface of the master element 2. Preferably, a device for adjusting the height of the laminating roller 7 is used for this purpose. In order to compensate for changes between the height of the master element 2 and / or changes in the positioning of the first carrier device 10, it is preferred that the height of the laminating roller 7 can also be adjusted. To this end, the laminating roller 7 can be lowered in steps of, for example, 50 μm until the desired pressure is reached between the laminating roller 7 and the master element 2. The reaching of the desired pressure can be recognized by a suitable sensor. After the pressure is reached or after the laminating roller 7 is positioned and adjusted, the laminating roller is rolled on the surface of the master element 2 so that the composite web 3 is brought into mechanical and optical contact with the master element 2 without gaps and bubbles. The rolling of the laminating roller 7 is indicated by a horizontal arrow to the left.

[0258] Fig. 16B A further stage of the method is shown after laminating the composite web 3 onto the surface of the master element 2. A dosing unit 28 for dosing an optical fluid 29 is applied to the surface of the master element 2 at one end of the first carrier device 10. To this end, the dosing unit 28 is lowered downwards from a storage position. The dosing unit 28 applies a quantity of optical fluid 29 onto the master element 2, wherein the quantity of optical fluid 29 is arranged to cover the contact surface between the input coupling element and the composite web. The dosing unit 28 is then returned to its storage position, as shown in FIG. Fig. 16C shown.

[0259] Fig.16D A height adjustment of the input coupling element 8 is schematically illustrated using a downwardly pointing arrow, which is used to bring the input coupling element 8 from a storage position into the vicinity of the master element 2 . Fig.16E The input coupling element 8 is shown after it has been positioned on the surface of the master element 2. In this case, the input coupling element 8 is in contact with the composite web 3, which in turn is laminated onto the surface of the master element 2. The contact surface 30 of the input coupling element 8 is applied to the composite web 3 so that the optical fluid 29 is located between the input coupling element 8 and the composite web 3. The optical fluid 29 is cross-linked with both the contact surface 30 and the composite web 3 due to capillary forces. As a result, the optical fluid 29 completely fills the gap between the contact surface 30 and the composite web 3. Since the refractive index of the optical fluid 29 is substantially the same as the refractive index of the input coupling element 8 and / or the upper carrier film of the composite web 3, the optical fluid prevents unfavorable reflections at the interface between the contact surface 30 and the composite web 3. In addition, the optical fluid 29 can act as a lubricant, thereby supporting the sliding of the input coupling element 8 on the surface of the master element 2. Capillary forces cause the optical fluid 29 to move along with the contact surface 30 when it moves along the surface of the master element 2. This is particularly important in view of the fact that the optical fluid 29 is not necessarily moved by the contact surface 30. Fig.16F Schematically depicted in .

[0260] The exposure is carried out synchronously with the movement of the input coupling element 8 over the surface of the master element 2. For this purpose, the scanning reference beam 11 is directed onto the input coupling element 8 in such a way that it is diffracted by the wedge shape to the desired exposure angle. The scanning reference beam 11 follows the movement of the input coupling element 8, for example by the laser itself moving along a track together with the scanning unit. This is done in Fig.16E and Fig.16F Schematically shown in FIG. After exposure, the input coupling element 8 is removed from the master element 2 (not shown). In order to overcome capillary forces and avoid deformation or distortion of the composite web, the input coupling element 8 is preferably moved laterally / longitudinally and upwardly in a continuous movement. Possible suction effects are advantageously avoided or reduced.

[0261] FIG. 17A to FIG. 17E An exemplary embodiment of the invention is shown, in which the input coupling element 8 has a cylindrical shape. FIG. 16A to FIG. 16E By way of example, an optical fluid 29 is introduced for improving the optical contact between the input coupling element 8 and the composite web 3 .

[0262] Fig.17A A lamination step is shown in which a lamination roller 7 is brought onto the surface of the composite web 3 so that the composite web 3 is captured between the lamination roller 7 and a first carrier 10 or master element 2. The lamination roller 7 rolls on the surface of the master element 2 so as to bring the composite web 3 into mechanical and optical contact with the master element. Fig. 17B and Fig. 17C A quantity of optical fluid 29 is shown being applied to the composite web 3. This is done by means of a height-adjustable dosing unit 28 in a manner similar to FIG. 16A to FIG. 16E During these steps, in this embodiment, the cylindrical input coupling element 8 remains in a storage position above the plane of the laminated composite web 3 .

[0263] The cylindrical input coupling element 8 is then positioned from the storage position to the accessible surface of the composite web 3 such that the composite web 3 is located between the input coupling element 8 and the first carrier device 10 or the master element 2. In this case, this positioning of the input coupling element 8 includes a downward movement, which is made possible by the height-adjustable storage of the input coupling element 8. The downward movement is Fig.17D Schematically depicted by a downward pointing arrow.

[0264] Fig.17E 2 shows the input coupling element 8 after it has been positioned on the master element 2. The figure also shows the introduction of the rolling movement of the input coupling element 8 on the master element 2. The contact surface 30 of the input coupling element 8 is applied to the composite web 3 so that the optical fluid 29 is located between the input coupling element 8 and the composite web 3. The optical fluid 29 is cross-linked with both the contact surface 30 and the composite web 3 due to capillary forces. Therefore, the optical fluid 29 completely fills the gap between the contact surface 30 and the composite web 3. Since the refractive index of the optical fluid 29 is substantially the same as the refractive index of the input coupling element 8 and / or the upper carrier film of the composite web 3, the optical fluid prevents unfavorable reflections at the interface between the contact surface 30 and the composite web 3.

[0265] Since the cylindrical input coupling element 8 is in contact with the composite web 3 only along a thin line or axis, the contact surface 30 between the cylindrical input coupling element 8 and the composite web 3 is smaller than the contact surface 30 between the wedge-shaped input coupling element 8 and the composite web 3. Therefore, a smaller amount of optical fluid 29 is sufficient to bridge the interface between the cylindrical input coupling element 8 and the composite web 3. Due to capillary forces, the optical fluid 29 is retained between the composite web 3 and the cylindrical input coupling element during its movement on the surface of the master element 2. This is Fig.17F Schematically shown in .

[0266] At the same time, the scanning reference beam 11 is directed to the input coupling element 8 synchronously as it moves. The scanning reference beam 11 follows the movement of the rolling input coupling element 8, for example by the laser itself moving along a track together with the scanning unit. Fig.17E and Fig.17F It is schematically shown in FIG.

[0267] Reference numerals list

[0268] F1 First side of the motherboard component

[0269] F2 Second side of the motherboard component

[0270] F3 Top of the motherboard component

[0271] F4 Second side of input coupling element

[0272] F5 First side of input coupling element

[0273] 1 Equipment

[0274] 2 Master Components

[0275] 3 Composite coils

[0276] 4 Spacers

[0277] 5 Absorption layer

[0278] 6 Master Hologram

[0279] 7 Lamination rollers

[0280] 8 Input coupling element

[0281] 9 Input coupling section

[0282] 10 First load-bearing device

[0283] 11 Reference beam

[0284] 12 Reconstructed signal / object wave

[0285] 13 Edge Lighting Reflection HOE

[0286] 14 Basal body

[0287] 15 A beam undergoing total internal reflection

[0288] 16 Edge-Illuminated Transmitted HOE

[0289] 17 Interference between the reference beam and the object beam

[0290] 18 Transmission HOE

[0291] 19 Reconstructing the beam

[0292] 20 repeat pitch

[0293] 21 Cover

[0294] 22 object beam

[0295] 28 Dosing unit for optical fluids

[0296] 29 Optical Fluid

[0297] 30 Contact surface of input coupling element

Claims

1. A device (1) for replicating a plurality of holograms, the device comprising: a first carrier device (10) for arranging a series of master elements (2) from a plurality of master elements (2) based on a plurality of holograms to be replicated in such a way that the upper faces of these master elements (2) are aligned in a horizontal plane, a laminating module for removably laminating a web of photosensitive composite (3) onto the aligned upper faces of the master elements (2), and an exposure module for exposing the master elements (2) in order to replicate the master holograms (2) into the photosensitive composite web (3), and a separation module for separating the exposed composite web (3) from the master elements (2), It is characterized in that The master elements (2) are detachably incorporated in the first carrier device (10) such that the sequence and / or composition of the master elements (2) for replicating the plurality of holograms is variable, and wherein the master elements (2) are further incorporated in the first carrier device (10) such that two or more faces of the master elements (2) are optically accessible for exposure.

2. The device (1) according to the preceding claim, characterized in that The apparatus (1) comprises a conveying module for conveying a web (3) of photosensitive composite material on the series of master elements (2).

3. The device (1) according to one or more of the preceding claims, characterized in that The master elements are separated along a linear arrangement in the first carrier device (10), wherein the master elements (2) are preferably separated by light-absorbing spacers (4) and / or wherein light-absorbing layers (5) are applied to vertical surfaces of the master elements (2).

4. Device (1) according to one or more of the preceding claims, characterized in that The device comprises one or more optically transparent input coupling elements (8), wherein the input coupling elements (8) can be applied to a composite web (3) laminated on the master elements so that during exposure, partial sections of the composite web (3) are captured between the one or more input coupling elements (8) and the master elements (2).

5. Device (1) according to one or more of the preceding claims, characterized in that The coupling elements (8) are arranged on a second, height-adjustable carrier device, wherein the lower side of the coupling elements (8) is preferably formed by a deformable, transparent coupling section (9).

6. Device (1) according to one or more of claims 4 to 5, characterized in that Each motherboard element (2) is assigned a corresponding input coupling element (8), wherein preferably at least the lower surface of the corresponding input coupling element (8) is consistent with the upper surface (F3) of the corresponding motherboard element (2).

7. Device (1) according to one or more of the preceding claims, characterized in that The first carrier device (10) is configured to arrange the master elements (2) in two parallel rows, wherein the rows of the master elements (2) are preferably separated by light absorbing spacers (4), wherein the spacers (4) are preferably part of the first carrier device (10).

8. The device (1) according to any one of the preceding claims, characterized in that The device (1) comprises a control unit, wherein the control unit comprises a processor and a memory and is configured to control the selection and optional arrangement of the sequence of the master elements (2), Therein, the processor reads the sequence data from the memory and sends a signal to the actuator and / or the user regarding the sequence in which the master elements (2) should be arranged.

9. Device (1) according to the preceding claim, characterized in that The sequence of exposure instructions is stored in the memory, wherein the processor sends a signal to a user and / or an actuator to set the position, path and / or wavelength of the light source according to the exposure instructions.

10. The device (1) according to any one of claims 8 and 9, characterized in that The control unit is connected to a sensor, wherein the sensor reads an ID feature of the individual master elements (2) or of the storage locations of these master elements and transmits the ID to the control unit for controlling and / or monitoring the sequence arrangement.

11. A system for replicating a plurality of holograms, the system comprising a device (1) according to any one of the preceding claims and a plurality of master elements (2), each of which comprises a substrate body (14) and at least one master hologram (6), wherein: A series of master elements (2) can be selected from the plurality of master elements (2) based on the plurality of holograms to be replicated.

12. The system according to claim 11, characterized in that The base bodies ( 14 ) of the master elements ( 2 ) have identical dimensions and preferably have a parallelepiped shape, wherein the base bodies ( 14 ) preferably comprise a height between 1 cm and 10 cm, a length between 3 cm and 20 cm and a width between 3 cm and 20 cm.

13. The system according to any one of claims 11 to 12, characterized in that At least two optically accessible faces of the master elements ( 2 ) are polished, wherein the polishing grade is preferably at least P3, wherein the optically accessible faces preferably have an anti-reflection coating.

14. The system according to any one of claims 11 to 13, characterized in that The substrate body (14) of these master elements (2) is formed of a material which is an optical plastic and / or an optical glass, wherein the optical plastic is preferably selected from the group consisting of polymethyl methacrylate (PMMA), polycarbonate (PC), cycloolefin polymer (COP), cycloolefin copolymer (COC), and the optical glass is preferably selected from the group consisting of borosilicate glass, quartz glass, B270, N-BK7, N-SF2, P-SF68, P-SK57Q1, P-SK58A and / or P-BK7.

Images