Method for replicating a hologram by means of an adhesive composite web

Abstract

The invention relates to a method for replicating a hologram into a light-sensitive composite web, comprising the following steps: Providing a master element comprising a substrate part and at least one master hologram; optionally providing an incoupling element; providing an adhesive composite web comprising a light-sensitive composite web and an optical adhesive film; applying the adhesive composite web to a surface of the master element or a surface of the optional incoupling element; exposing the master element in order to replicate the at least one master hologram into the light-sensitive composite web, the optical adhesive film establishing optical contact between the light-sensitive composite web and the master element, or between the light-sensitive composite web and an incoupling element, wherein an incoupling element is optionally used for the exposure; and detaching the adhesive composite web from the master element or the incoupling element.

Description

[0001] Method for replicating a hologram using an adhesive composite sheet

[0002] DESCRIPTION

[0003] The invention relates to a method for replicating a hologram in a light-sensitive composite web, comprising the following steps: providing a master element comprising a substrate body and at least one master hologram, providing an adhesive composite web comprising a light-sensitive composite web and an optical adhesive film, applying the adhesive composite web to a surface of the master element, exposing the master element to replicate the at least one master hologram in the light-sensitive composite web, wherein the optical adhesive film mediates optical contact between the light-sensitive composite web and the master element or between the light-sensitive composite web and a coupling element, and detaching the adhesive composite web from the master element.

[0004] In a further aspect, the invention relates to a method for replicating a hologram in a light-sensitive composite web using a coupling element, wherein the adhesive composite web is applied to a surface of the coupling element and wherein, during exposure, the optical adhesive film provides optical contact between the light-sensitive composite web and the coupling element or between the light-sensitive composite web and the master element.

[0005] Background and state of the art

[0006] The invention relates to the field of hologram replication.

[0007] HOEs (Holographic Optical Elements) typically refer to optical components in which holographic properties are used to achieve a specific light beam path, such as transmission, reflection, diffraction, scattering, imaging, redirection, and / or deflection, etc. This allows desired optical functionalities to be implemented compactly in any substrate. The holographic properties preferably exploit the wave nature of light, particularly coherence and interference effects. Both the intensity and phase of the light are taken into account.

[0008] Such holographic elements are used in many areas, such as transparent displays (e.g., in shop windows, refrigerated cabinets, vehicle windows), for lighting applications such as information or warning signals in glass surfaces, and light-sensitive detection systems, for example, for interior monitoring (eye tracking in vehicles or presence status tracking of people indoors). Holograms are generated by the interference of a reference beam with the light reflected or diffracted from the surface of an object (object rays). Traditionally, three-dimensional objects were used to create unique, customized holograms. Commercially available HOEs, on the other hand, are often mass-produced using duplication processes.

[0009] Reproduction processes typically use a master hologram containing the image to be copied. The master holograms used are often stored in a substrate body that carries the master hologram. The substrate body is preferably transparent and can have various shapes, such as a cuboid, a plate, or a cylinder. The combination of the master hologram and the substrate body forms a master element.

[0010] The master element is illuminated with a coherent light source to replicate the image from the master hologram into a photosensitive composite. For mass production, the photosensitive composite can be provided in the form of a flowing web comprising a photosensitive material and one or more carrier or protective films. For this purpose, the photosensitive web is preferably transported through various workstations to produce the HOEs.

[0011] During exposure, the composite sheet is placed on or brought into contact with a surface of the master element. To create a reflection hologram, the coherent light can traverse the composite sheet before reaching the master hologram and being reflected back into the composite sheet. Alternatively, to create a transmission hologram, the coherent light can first be directed onto the master hologram, by which it is diffracted before reaching the composite sheet. In both cases, the object and reference beams interfere with each other in the light-sensitive material, forming the replicated hologram. The replication process is sensitive to unwanted stray light, which can also interfere with the object and / or reference beams.If, for example, irregularities or gaps occur at the interface between the composite sheet and the surface of the master element, the reference and / or object beams can be internally reflected. This can lead to either light loss or unwanted interference, which impairs the quality of the replicated hologram. Ensuring sufficient optical contact between the master element and the composite sheet is therefore highly relevant for the quality of the replicated hologram.

[0012] This also applies to the possible use of coupling elements in the exposure process, which are used in certain configurations to replicate the holograms. Coupling elements can, for example, be used preferentially to adjust an exposure angle. The exposure angle, i.e., the angle at which the object and reference beams strike the light-sensitive material, is important for the subsequent reconstruction of the replicated hologram. Varying the exposure angle thus enables the production of different types of holograms, for example: edge-lit, backlit, at eye level, or only visible from below, etc.

[0013] By passing the coherent light used to expose the hologram through a coupling element, the exposure angle can be varied or adjusted. The coupling element is transparent to at least the wavelength of the exposure beam and can take on various shapes, such as a cuboid, a plate, a pyramid, a cylinder, etc. The coupling element can also be placed on the composite sheet so that the light is first refracted by the material of the coupling element to achieve a desired approach angle on the composite sheet. However, if small gaps exist at the interface or boundary between the coupling element and the composite sheet, the light can be internally reflected. This also leads to unwanted interference or losses.Therefore, in such constellations, a nearly perfect optical contact between the coupling element and the composite track is also desirable in order to produce high-quality replicated holograms.

[0014] To improve the optical contact between the composite web and adjacent components (such as master elements or coupling elements) in an exposure process, the use of index-matching liquids has been proposed. WO 9619754 A1 teaches a method for replicating a master hologram from a hollow, drum-shaped master element into a composite web. The composite web flows over a curved surface of the rotating master element. It was found that image artifacts caused by internal reflections at air / glass or air / substrate interfaces were caused when the optical contact between the optical components was insufficient. To improve the optical contact between the composite web and the master element, an index-matching liquid such as xylene is continuously applied to the surface of the master element. The liquid fills gaps between the master element and the composite web.Additionally, the composite web is immersed in an index match fluid before exposure. After exposure, the fluid must be removed from the composite web before it can be rolled up or further processed.

[0015] A disadvantage of the proposed process, however, is that xylene is a highly flammable irritant and suspected of being carcinogenic, so its use requires greater plant complexity to ensure explosion protection, environmental protection, and occupational safety. Furthermore, the necessary removal of the index match fluid increases the complexity and effort of the HOE production process. JP2000250386A also discloses the use of an index match fluid to improve the optical contact between a master element and a photosensitive composite web. The index match fluid must not be too volatile, as it must remain in a liquid state for the duration of the coating and exposure process. However, the index match fluid is dried from the exposed composite web before further processing. This, in turn, significantly increases plant complexity.In addition, a liquid index match must be very thin to prevent molecular movement in the liquid film from altering the phase position of the passing light, which would negatively impact the quality of the holograms. The index match liquid is also usually lost upon removal, meaning it cannot be reused. This further increases the cost of the entire process.

[0016] Low-volatility index match fluids that do not dry quickly may remain on the surfaces of the master hologram or other components for longer. This may require cleaning the master hologram to prevent the accumulation of fluids and contaminants. This cleaning step can be laborious, especially if the master hologram has a non-smooth surface (e.g., a relief pattern). Current technology offers only limited solutions for protecting the surfaces of master holograms when they come into contact with liquid or resinous materials.

[0017] The use of optically transparent layers is known to protect a master hologram from contamination during an exposure process. DE 10 2006 016 139 A1 discloses the use of a transparent release layer between a resinous (non-solid) photosensitive layer and a master hologram. The release layer is intended to facilitate removal of the resinous photosensitive layer from the master hologram. To minimize the optical influence of the release layer, the difference in refractive index between the photosensitive layer and the release layer is intended to be minimized or completely eliminated. The release layer should therefore have no optical effect.

[0018] In addition, the release layer can serve as a cover layer for the relief structure of the master hologram. Despite the release layer being depicted as very thin, the relief structure of the master hologram remains sharp and can be pressed into the photosensitive layer. DE 10 2006 016 139 A1 suggests that the release layer is a coating that is permanently applied to a surface of the master hologram. The resinous photosensitive layer is preferably temporarily applied to the release layer together with a carrier film and separated from the release layer after exposure. In the field of optical displays, it is also known to use optical clearance adhesives (OCAs) to connect a backlight and a screen.

[0019] KR20150001411A teaches an example of such an OCA for use in an LCD screen. The OCA comprises an adhesive and prevents the formation of an air layer between the backlight and the LCD screen. Similarly, US10611937B2 teaches an adhesive layer used to firmly bond a glass layer to a sensor film of a screen. The adhesive layer comprises an OCA to ensure good optical performance of the screen. Such an adhesive layer is intended to permanently bond the screen layers together to ensure a long product life. Removal of the adhesive layer is not intended.

[0020] In light of the state of the art, there is therefore a need to improve processes for replicating holograms in a light-sensitive material with regard to efficiency, cost-effectiveness, and the optical quality of the replicated holograms. In particular, there is a need to improve the optical contact between a light-sensitive composite web and other optical components such as the master element or a coupling element used in an exposure. The improved optical contact should support reliable exposure without interference, require no hazardous chemicals or excessive cleaning, and offer easy handling of the materials and devices used. Furthermore, it is desirable that the means for improving the optical contact remain as clean as possible, have higher transparency and low haze, and minimize the introduction of additional optical interfaces.

[0021] Object of the invention

[0022] The object of the invention is to provide a method for replicating a hologram from a master element into a light-sensitive composite web without the disadvantages of the prior art. In particular, the object of the invention was to provide a method suitable for the material-friendly replication of holograms on a light-sensitive composite web with high optical precision and quality.

[0023] Summary of the invention

[0024] The object is achieved by the features of the independent claims. Advantageous embodiments of the invention are described in the dependent claims.

[0025] In a first aspect, the invention relates to a method for replicating a hologram in a photosensitive composite web, comprising the following steps: a. Providing a master element comprising a substrate body and at least one master hologram, b. Providing an adhesive composite web comprising a photosensitive composite web and an optical adhesive film, c. Applying the adhesive composite web to a surface of the master element, d. Exposing the master element to replicate the at least one master hologram in the photosensitive composite web, wherein the optical adhesive film mediates optical contact between the photosensitive composite web and the master element or between the photosensitive composite web and a coupling element, and e. Detaching the adhesive composite web from the master element.

[0026] In a further aspect, the invention relates to a method for replicating a hologram in a light-sensitive composite web, comprising the following steps: a. providing a master element comprising a substrate body and at least one master hologram, b. providing a coupling element, c. providing an adhesive composite web comprising the light-sensitive composite web and an optical adhesive film, d. applying the adhesive composite web to a surface of the coupling element, e. aligning the coupling element to the master element so that the adhesive composite web comes into temporary contact with the master element, f.Exposing the master element using the coupling element to replicate the at least one master hologram in the photosensitive composite web, wherein the optical adhesive film provides optical contact between the photosensitive composite web and the coupling element or between the photosensitive composite web and the master element, and g. Detaching the adhesive composite web from the coupling element.

[0027] The method according to the invention has the advantage that the adhesive composite sheet can be applied to an optical component (i.e., a master or coupling element) with essentially no gaps. This ensures virtually flawless optical contact between a master element or a coupling element and the light-sensitive composite sheet without the need for additional steps for cleaning or evaporating an index-match liquid. Instead, a residue-free removable optical adhesive film can create a smooth, gap-free transition between the master element or the coupling element and the composite sheet, so that essentially no unwanted reflections or scattering occur at interfaces between the components. This reduces optical losses and minimizes the possible occurrence of optical interference that could leave undesired patterns in the replicated hologram.Another particularly advantageous feature is that the optical adhesive film can adhere sufficiently to both the master element or the coupling element and the light-sensitive composite web to prevent the occurrence of bubbles or air gaps.

[0028] The provision of an adhesive composite web comprising the photosensitive composite web and an optical adhesive film enables synchronous movement of the photosensitive composite web and the optical adhesive film through the stations of a replication process. Separate transport rollers are therefore not required to move the photosensitive composite web and the optical adhesive film. Precise synchronization of a large number of transport rollers to avoid excessive pulling of the optical adhesive film or the photosensitive composite web is also not required. A replication device can thus be manufactured and operated with fewer requirements. The risk of the optical adhesive film being stretched or torn is reduced.

[0029] Furthermore, the combination of optical adhesive film and photosensitive composite web significantly increases the tensile strength (or tear strength) of the adhesive composite web. The resulting adhesive composite web can therefore be subjected to higher forces than would be the case for an optical adhesive film alone or a photosensitive composite web alone. Consequently, the adhesive composite web can be fed through a replication device at a higher speed than would be the case for an optical adhesive film alone. Since the requirements for the tensile strength (or tear strength) of the optical adhesive film are therefore lower, it can advantageously be manufactured from a wider range of materials and layer thicknesses, including materials that would be too soft or have too low a tensile strength on their own.This allows the material and construction of the optical adhesive film to be more flexibly optimized for a suitable refractive index and low haze.

[0030] Since the optical adhesive film of the invention does not have to meet the mechanical requirements of a stand-alone film web, it can advantageously be particularly soft and / or elastic. This allows it to be advantageously provided with optimal weak adhesion, which is suitable for particularly seamless application to the surface of an optical component. A suitable elastic property is preferably designed to compensate for typical roughness or unevenness of the surface of optical components to which the optical adhesive film is applied. This allows a particularly continuous and cohesive optical contact to be achieved.

[0031] Furthermore, in preferred embodiments, the elastic property can be adjusted such that the optical adhesive film is essentially only adhesive when pressed against a solid surface with a minimum pressure. When the applied pressure is released and / or when the optical adhesive film is passed through a replication device, the adhesive property of the optical adhesive film can essentially not occur. This contributes to keeping the optical adhesive film clean and dust-free. The use of optical adhesive films with higher adhesion, in particular for pressure-free application to the surface of a master or coupling element, is also possible within the scope of the present invention.

[0032] Advantageously, the optical adhesive film, particularly in preferred forms, can be constructed from a single homogeneous material layer. Even if this results in reduced tensile or tear strength, a separate carrier layer can be omitted from the optical adhesive film's construction without significant restrictions regarding the web speed in the replication device.

[0033] Instead, the provision of an adhesive composite web, in which the light-sensitive composite web and the optical adhesive film are already bonded together, ensures sufficiently high mechanical stability to withstand deformation or damage even at high web speeds.

[0034] By choosing a single-layer structure for the optical adhesive film, which preferably consists of only a single homogeneous material layer, optical interfaces within the optical adhesive film can be advantageously reduced and any optical interference further minimized. In particular, the optical adhesive film can have a single constant refractive index, so that electromagnetic radiation is not refracted within its structure. Furthermore, the optical adhesive film itself can be particularly thin. All of these aspects can reduce the haze of the optical adhesive film to prevent a light-scattering effect. The precision and sharpness of an exposure are therefore essentially unaffected by the presence of the optical adhesive film. Holograms can be reproduced with high precision and quality.

[0035] A further advantage of the method according to the invention is that the materials used for the optical adhesive film can have identical or similar optical properties to those used for the substrate of the master element (or the coupling element) and / or the light-sensitive composite web. Preferably, the similar or identical properties include transparency, haze, stress birefringence properties, and / or the refractive index. The use of identical or similar materials enables a very close adaptation of the refractive index of the optical adhesive film to the refractive indices of an adjacent optical component, thus ensuring a transition between the adjacent refractive indices without refractive index jumps.Reflections at the interface between the master element (or the coupling element), the optical adhesive film and / or the light-sensitive composite web are thereby largely eliminated or significantly minimized.

[0036] By optically contacting by means of an adhesive composite web comprising an optical adhesive film, the exposure can also be easily integrated into a continuous manufacturing process, preferably into a roll-to-roll process. The adhesive composite web can be continuously moved through a replication device using known techniques, e.g. with the aid of rollers. This enables simple synchronization of the adhesive composite web with optical components of the replication device or other films, such as protective films. It is also possible and may be preferred for the adhesive composite web to be applied to the surface of the master element or the surface of the coupling element by a laminating roller. During exposure, the optical adhesive film of the adhesive composite web is in particular in mechanical contact with the light-sensitive composite web and the master element and optionally the coupling element.Thus, the optical adhesive film, as a component of the adhesive composite web, reliably provides improved optical contact between the light-sensitive composite web and the master element or coupling element. Interference caused by any unwanted refraction of an exposure beam as it passes through the light-sensitive composite web, the optical adhesive film, and the surface of the master element or coupling element is minimized.

[0037] The "optical adhesive film" is preferably a solid in which the Brownian motion is sufficiently small, preventing any "wobble" in the phase of the light and thus ensuring a more stable interference field in the hologram copy within the exposure time. The microstructures do not blur, thus maximizing the diffraction efficiency of the holograms. The sharpness and contrast of the generated hologram are also significantly improved. The optical adhesive film is preferably designed to adhere to a surface of the light-sensitive composite sheet and an adjacent surface of the master element and / or coupling element. The strength of the adhesion during exposure is preferably so high that a seamless connection can be achieved between the light-sensitive composite sheet and the adjacent optical component (master element and / or coupling element).It is particularly preferred that, to ensure adhesion, the light-sensitive composite web does not have to be pressed so strongly onto the surface of the master element or the coupling element that material deformation of the light-sensitive composite web occurs. At the same time, the strength of the optical adhesive film's adhesion to these components (master element and / or coupling element) should preferably be so low that the optical adhesive film can be removed without damage or residue. In this sense, the optical adhesive film of the invention preferably further differs from the adhesive layers of the prior art, such as KR20150001411A, US10611937B2, and DE 10 2019 112 254 A1, which are designed for the permanent bonding of optical components of a product.

[0038] Furthermore, it is preferred that the optical adhesive film be provided in the form of a film or foil. This means that the material of the optical adhesive film does not first form a film or foil while the film is being applied (e.g., by spraying) to the surface of the master element or coupling element. Instead, the optical adhesive film preferably already has a defined width and thickness in the provided adhesive composite sheet.

[0039] Optical adhesive films can be more precisely specified with regard to their layer thickness, layer thickness homogeneity, and waviness. For example, the optical adhesive film can advantageously be provided with a desired, constant thickness so that the intensity of the light used with the same exposure source to expose the photosensitive composite web remains uniform throughout. In contrast, when using index-match liquids, the dosage can vary over time, and there is no guarantee that the liquid will be evenly distributed over the desired surfaces. A similar problem can arise when applying hot-melt adhesives, as these are also dispensed in liquid form. The use of an optical adhesive film with a specifiable layer thickness, layer thickness homogeneity, and waviness also leads to high process stability in the copying process.In particular, the surfaces of the optical adhesive film can be designed to be essentially waviness-free. This avoids fluctuations in the thickness of the adhesive film, which could blur the interference field of the object and reference beams and lead to deviations in the optical function of the replicated hologram from the master hologram.

[0040] Compared to the prior art processes based on index match fluids, the use of an optical adhesive film can also be made safer for the user. This is due, among other things, to the fact that such an adhesive film generally does not contain highly toxic substances and is non-volatile, thus eliminating the need for special safety measures (such as gas extraction or insulation).

[0041] Furthermore, volatile index match liquids generally cannot be recovered after use. This means that they either evaporate or lack the required degree of purity, which allows reuse only after complex redistillation. This increases the material or equipment requirements and makes the process more expensive. In contrast, the optical adhesive film can be reused for a variety of applications in preferred embodiments. For example, the material of the optical adhesive film can advantageously be removed from the replicated hologram in the light-sensitive composite web and reused or recycled. The process according to the invention can therefore advantageously be designed to save resources in various ways.

[0042] The method according to the invention is also extremely gentle on materials, clean, and leaves no residues on the optical components, such as the master element or the coupling element. This is preferably due to the relatively weak adhesive force of the optical adhesive film, particularly with respect to optical components such as the master element or the coupling element, and to the fact that it can be removed continuously or intermittently from the surfaces of the optical components. In this way, fresh optical adhesive film can also be applied to the surfaces continuously or intermittently. The optical adhesive film is therefore preferably not a sticky, permanent component of a device that could accumulate dust or residues.Even in the case of preferential removal of the optical adhesive film from the photosensitive composite web, residues on the exposed photosensitive composite web are avoided, so that the produced hologram can be seamlessly integrated into a final product - preferably without a further cleaning step. This improves the efficiency of the process and eliminates additional (cleaning) steps. Alternatively, it may also be preferable to leave the optical adhesive film on the photosensitive composite web even after replication of the hologram, thus providing an exposed adhesive composite web for integration into a final product. For example, the optical adhesive film can also mediate optical contact between the replicated hologram in the photosensitive composite web and other surfaces of the final product for integration into a final product.The proposed method thus proves to be extremely flexible with regard to various requirements for later integration of the replicated holograms.

[0043] A further advantage of the process according to the invention is that the photosensitive composite web, or at least an outer layer thereof, can be configured either as a solid or as a non-solid material. The photosensitive material can, for example, be solid and / or enclosed between solid carrier films such as polycarbonate films. The solid carrier films can be brought into contact with the surface of a master or coupling element, which can also be completely smooth (without a relief pattern). As a rule, it is difficult to bring two smooth, solid surfaces into good optical contact with each other. The intermolecular forces acting between the smooth surfaces are often not strong enough to bring them into continuous contact, and the surfaces can even electrostatically repel each other.By applying the adhesive composite sheet to the surface of the master or coupling element with the optical adhesive film facing the surface of a master or coupling element, stronger attractive electrostatic forces can be generated between the adhesive composite sheet and the surface, ensuring stable contact. Relative movement between the adhesive composite sheet and the master or coupling element is avoided, improving the quality of the replication process.

[0044] As can be seen from the above-mentioned advantages, a method in which the adhesive composite sheet is applied to a master element so that the optical adhesive film mediates optical contact between the photosensitive composite sheet and the master element (or a coupling element) solves the same technical problem as a method in which the adhesive composite sheet is applied to the coupling element so that the optical adhesive film mediates optical contact between the photosensitive composite sheet and the coupling element (or a master element). The optical adhesive film primarily improves the optical contact between the photosensitive composite sheet and the surface of an optical component that guides or redirects the exposure radiation onto the photosensitive composite sheet. This reduces unwanted reflections, scattering, or losses and improves the quality of the reproduced hologram.Depending on the requirements of the replication process, the adhesive composite web can be applied to the master element or a coupling element. Depending on the orientation of the adhesive composite web, during exposure through the optical film, optical contact can be established between the light-sensitive composite web and the optical component (in particular the master or coupling element) to which the adhesive composite web was initially applied, or the optical component (in particular the master or coupling element) with which the adhesive composite web is preferably subsequently brought into contact for exposure. The processes are therefore interconnected in such a way that they implement a single general inventive concept.

[0045] The person skilled in the art will also recognize that preferred features or advantages of embodiments of the method in which the adhesive composite web is applied to the master element also apply to embodiments of the method in which the adhesive composite web is applied to the coupling element, and vice versa. Clearly, a combination of the methods may also be preferred. This means that when using a coupling element in the exposure process, it may be particularly preferred to use two optical adhesive films on both sides of the adhesive composite web, so that one optical adhesive film in each case provides the optical contact between the light-sensitive composite web and the coupling element or the master element. Within the meaning of the invention, "applying" the adhesive composite web to an optical component (e.g., a master element or a coupling element) means that the optical component is brought into contact with the adhesive composite web (e.g.,by means of pressing and / or lamination), wherein the contact is preferably large-area and / or not short-term. Large-area contact preferably extends over a section of the adhesive composite sheet with a length of more than 0.5 cm, preferably more than 1 cm, preferably more than 5 cm, preferably more than 10 cm, even more preferably more than 20 cm or more. More than just short-term contact is preferably maintained for at least 1 second, preferably at least 10 seconds, at least 1 minute or more. In preferred embodiments, the adhesive composite sheet is applied to an optical component for a period of 10 seconds to 20 minutes, preferably 30 seconds to 10 minutes.

[0046] Preferably, applying an adhesive composite sheet over the surface of another optical component means that at least a portion of the adhesive composite sheet assumes the shape of the surface to which it is applied. For example, if the adhesive composite sheet is applied to a cylindrical optical component, the adhesive composite sheet preferably contacts a surface of the optical component more than tangentially. For example, if the adhesive composite sheet is applied to a planar optical component, the adhesive composite sheet will preferably assume the shape of the planar surface.It is additionally preferred that the application of an adhesive composite sheet to the surface of an optical component creates a continuous contact between the optical adhesive film or the photosensitive composite sheet and the surface or a portion thereof, which may require partial deformation of the optical adhesive film or the photosensitive composite sheet. For this purpose, in preferred embodiments, pressure can be applied to the adhesive composite sheet.

[0047] For the purposes of the invention, "bringing into contact" preferably refers to indirect or direct contact between two process components, such that at least one point of a first process component is in direct or indirect contact with a point of the second process component, wherein the contact is at least fleeting. However, the contact can be larger and / or more permanent. Bringing an adhesive composite sheet into contact with an optical component preferably results in a contact area being created between the adhesive composite sheet and the optical component, which contact area does not necessarily have to be large, for example, 0.5 - 10 mm in length. The contact area preferably creates optical contact between the two optical components.The contact area can be provided, for example, by aligning the curved surface of one optical component with respect to the flat surface of another optical component such that the adhesive composite track is enclosed between the two optical components along a preferably relatively thin contact line (e.g. with a contact line width between 0.5 and 10 mm).

[0048] In this sense, for example, an alignment of a preferably cylindrical coupling element with a master element with a flat surface can also be achieved, so that the adhesive composite web comes into temporary contact with the master element. Such an alignment between two optical components (preferably between the master element and the coupling element) particularly means a relative movement between the two optical components, whereby, for example, both the coupling element and the master element can be moved relative to the coupling element and the master element can be moved relative to the coupling element.

[0049] For the purposes of the invention, "temporary contacting" preferably means that the contact between the process components is maintained substantially for a period of time necessary for the exposure of the hologram. Preferably, the period of time is significantly shorter than the duration of a complete replication cycle, for example, by a factor of 2, 3, 4, or more. The duration of a replication cycle preferably refers to the time required to replicate a single hologram in a semi-continuous or intermittent process, as further explained with respect to certain preferred embodiments. The duration of temporary contact may, for example, be less than 1 minute, preferably less than 10 seconds.In particularly preferred embodiments, the temporary contacting is a result of rolling a roller-shaped optical component over a flat surface of another optical component, so that the contact section produced moves with the rolling movement.

[0050] The term "optical component" preferably refers to one or more components or elements used to influence electromagnetic radiation for the purpose of exposure. The optical component is preferably a master or coupling element.

[0051] A "process component" within the meaning of the invention is preferably a stationary, movable, or consumable component or material used in the replication process. The process component is preferably configured to interact with the radiation in the exposure process, for example, by reflection, transmission, or diffraction, in order to adjust the exposure process. For example, optical components such as a master element or coupling element, as well as an adhesive composite web or (not necessarily optical) components of a replication device such as lamination rollers, deflection rollers, and laminating rollers, represent process components within the meaning of the invention. Within the meaning of the invention, the "surface" of an optical component (such as a master element or a coupling element) is the entire surface or a portion thereof that is brought into contact with the adhesive composite web.The "surface" of an optical component may preferably also refer to its outermost layer, particularly in the case of a layered optical component. For example, the surface of a master element may be its top cover, which serves to protect the master hologram.

[0052] For the purposes of the invention, "detachment" is a separation, preferably the separation of the process components such that they are no longer in contact with one another, preferably neither in direct nor indirect contact. Therefore, "detachment" preferably involves introducing an increasing gap between the process components, for example, during detachment of the adhesive composite web from a master element or coupling element. A detachment step preferably requires the application of a peel force to separate the components, wherein the peel force preferably exceeds a threshold value determined by the adhesion between the components.

[0053] An "optical contact" should preferably allow a light beam to pass between process components without experiencing significant reflections or even total internal reflection. Direct, integral contact between the process components is possible, but not necessary. For example, the optical adhesive film plays a key role in mediating optical contact between the master element (or a coupling element) and the light-sensitive composite web, as explained in more detail herein. Thus, the optical adhesive film can particularly advantageously create a smooth, gap-free transition between the master element (or a coupling element) and the light-sensitive composite web.In preferred embodiments, particularly when carrying out an exposure of the master element with the aid of a coupling element, it may be preferred that the adhesive composite web has an optical adhesive film on both sides in order to mediate the optical contact between the light-sensitive composite web and the master element as well as the coupling element.

[0054] However, in embodiments, it can also be provided that, in this case too, an optical adhesive film is provided only on one side, so that on a remote side, optical contact between the light-sensitive composite web and a master or coupling element is not mediated by the optical adhesive film. Thus, the carrier film of the light-sensitive composite web itself can be designed to mediate preferably gap-free contact with a master or coupling element, or in preferred forms, the light-sensitive material of the light-sensitive composite web contacts the master element or coupling element directly to provide preferably gap-free contact. Direct optical contact is preferably established between the optical adhesive film and an adjacent optical component.If a gap exists between the surfaces of the optical adhesive film and the adjacent optical component, it is preferably smaller than half a wavelength of the exposure radiation, so that no interference fields form at the interface between the surfaces. Preferably, neither reflection (especially total internal reflection) nor scattering occurs at the interface between the surfaces.

[0055] The optical contact between the light-sensitive composite web and an optical component (master element, coupling element) is preferably mediated by the optical adhesive film. This preferably means that when the adhesive composite web is applied to a surface of an optical component, the optical adhesive film is oriented towards the surface of the optical component. The optical adhesive film is thus in mechanical contact with the light-sensitive composite web and with the surface of the optical component. This preferably means that the optical adhesive film adheres physically, chemically, or electrostatically to the light-sensitive composite web and the surface of the optical component in order to bond the light-sensitive composite web to the surface, at least in sections, for exposure. This bond is preferably gap-free and substantially free of refractive index jumps.

[0056] For the purposes of the invention, "light sensitivity" preferably refers to a material's holographic suitability. A material is preferably considered holographically suitable if, upon exposure to sufficiently coherent electromagnetic radiation (or "light"), the interference fields of the radiation can be stored as microstructures in the material. Holographic suitability is preferably related to the size of the resulting microstructures. The resulting microstructures are preferably no larger than the light / dark structures of an interference field.

[0057] For the purposes of the invention, "exposure" preferably refers to the targeted directing of electromagnetic radiation, preferably in the wavelength range between 400 and 1600 nm, onto a correspondingly sensitive surface, preferably to form a hologram. Various methods for exposing a hologram are known, including transmissive or reflective techniques for producing volume holograms. Examples of these will be explained in more detail later in this text.

[0058] A "master element" is preferably a three-dimensional unit comprising at least one master hologram in a shape that ensures that a movement of the master element directly leads to a corresponding movement of the master hologram. A master element can also comprise a plurality of master holograms, for example 2, 3, 5, or more. Depending on the embodiment, the master element can preferably have any geometric shape, including shapes with flat or curved surfaces. The master element can, for example, be designed as a cylinder, cuboid, prism, pyramid, wedge, or any other suitable shape. The master element preferably has a length and width that approximately correspond to that of the master hologram. The master element is preferably at least twice, preferably five times, and particularly preferably at least twenty times as high as the master hologram.

[0059] The master element preferably comprises a substrate body that either encloses or supports the at least one master hologram. In embodiments, the master element may, for example, comprise a transparent top cover for protecting a master hologram located between the cover and the substrate body. Preferably, the top cover has a refractive index selected to allow light to pass through it, the master hologram, and the substrate body without significant diffraction. The top cover may, for example, be a transparent film or a glass layer.

[0060] The master element may preferably have the shape of a cuboid block, a plate, a pyramid, a prism, or a cylinder. The substrate body may be shaped accordingly.

[0061] Preferably, the substrate body of the master elements can be formed from a material which is an optical plastic, preferably selected from the group: polymethyl methacrylate (PMMA), polycarbonate (PC), cycloolefin polymers (COP) and cycloolefin copolymers (COC) and / or an optical glass, preferably selected from the group: borosilicate glass, quartz glass, B270, N-BK7, N-SF2, P-SF68, P-SK57Q1, P-SK58A and P-BK7.

[0062] Preferably, both the substrate body and any cover of the master element have a refractive index between 1.4 and 1.6.

[0063] The choice of material for the substrate body may depend on the desired exposure angle or refractive index. It may also be preferable for a substrate body to be colored, for example, to filter light wavelength-selectively to create a hologram with a specific wavelength. In this way, a broadband light source can be used to expose various master holograms.

[0064] It is preferred that the surface of the master element comprises glass, PC, TAC, or PMMA. The surface material can be in the form of a film or plate to protect the master hologram. However, the surface material can also be the material of the substrate body itself and, for example, have a cuboid or cylindrical shape. Whether an adhesive composite sheet is applied to or brought into contact with a substrate or a cover of a master element can depend on the direction from which the master hologram is to be exposed. The surface of the master element to which the adhesive composite sheet is applied is preferably smooth, which means in particular that it does not comprise a relief pattern. The master hologram preferably comprises a volume hologram.For volume hologram replication, the quality of the reproduction depends primarily on the optical rather than mechanical contact between the master hologram and the light-sensitive material used. A smooth surface of the master element also makes it easier to apply and remove the adhesive composite sheet without leaving residue, for example, in the recesses of a relief pattern.

[0065] Preferably, the "width" refers to a dimension in a horizontal plane transverse to a composite web movement direction. Preferably, the "length" refers to a dimension in a horizontal plane longitudinal to a composite web movement direction. Preferably, the "height" or "thickness" refers to a dimension in a vertical plane orthogonal to the plane formed by the width and length.

[0066] A “substrate body” within the meaning of the invention is preferably a three-dimensional block of material which carries or encloses the master hologram. The substrate body is preferably transparent. In some embodiments, the substrate body has a plurality of surfaces, including a flat surface which may be horizontally oriented. In some embodiments, the substrate body is a general cylinder, i.e. it has a constant cross-section of any shape, e.g. square, polygonal, elliptical or circular. The ends of the substrate body which have the shape of the cross-section can be referred to as the “base surface”. The elongated surface of the substrate body which lies between the two ends can be referred to as the “lateral surface”. In some embodiments, the shape of an axially rotatable circular cylinder is preferred. Within the meaning of the invention, the shape of a rotatable cylindrical or prismatic substrate body orMaster element, preferably a vertical cylinder, also referred to as a “roller”.

[0067] For the purposes of the invention, the term "transparent" or "transparency" preferably refers to a property of a material whereby it is substantially permeable to electromagnetic radiation. A transparent material within the meaning of the invention is preferably transmissive for at least part of the electromagnetic spectrum, preferably with a wavelength between 300 nm and 25 pm, particularly preferably between 400 nm and 780 nm. A transparent material, for example a transparent substrate body, is particularly preferably permeable to light within a wavelength range with which the master holograms are exposed. A transparent material can also be colored to select light radiation of a specific wavelength.

[0068] A "master hologram" within the meaning of the invention is preferably a holographic-optical element suitable for functioning as an original, from which at least one replicated hologram can be produced. The master hologram is designed for an optical function for one or more wavelengths. For this purpose, for example, several holograms, each diffracting light of one wavelength, and / or multiplex holograms diffracting light of several wavelengths, can be arranged as hologram stacks. The optical function of a master hologram can preferably be an imaging function or a scattering function. The radiation incident on the master hologram is diffracted, in particular at the intended wavelength or angle of incidence. The diffraction allows the optical function inscribed in the master hologram (e.g., imaging, scattering, and / or deflection) to be reconstructed.

[0069] The master hologram can, for example, be a diffractive optical element (DOE). Diffractive optical elements (DOEs) utilize a surface relief profile with a microstructure for their optical function. Alternatively, the microstructure can also be present in the volume of the element, e.g., in the form of a local difference in the refractive index. The light transmitted by a DOE can be converted into almost any desired distribution through diffraction and subsequent propagation. This can be an image, a logo, text, a light refraction pattern, or similar. The master hologram preferably comprises a volume hologram.

[0070] It is particularly preferred that the master hologram is a reflection hologram. Furthermore, it is preferred that the master hologram is a volume hologram.

[0071] The process for producing the master hologram can preferably be referred to as "hologram origination" or "hologram mastering". The master hologram can be created using an analog or digital process. In an exemplary analog process, a first coherent beam, the object beam, is reflected from an object and onto a recording material, which is simultaneously exposed to a second coherent beam, the reference beam. The object beam and the reference beam interfere and create an interference pattern on or in the recording material (i.e., the photosensitive material). This interference pattern is recorded by the photosensitive material, so that after processing, the shape of a surface relief pattern on a surface of the material or a spatially varying refractive index is created in the material, which is usually only a few micrometers thick.To view an image of the original object, the master hologram can be illuminated with light diffracted by the recorded surface relief pattern or refractive index pattern. This diffracted beam contains the image of the original object. The master hologram can then be used as a new object when creating further copies with the same image.

[0072] The master hologram can preferably also be computer-generated. The microscopic gratings that produce the diffraction effects can be produced, for example, by laser interference lithography. In this technique, two or more coherent light beams are configured to interfere at the surface of a recording material. The positions of the light beams relative to the recording material can be controlled by a computer. Depending on the strength of the laser, the recording material can be made of almost any material. Other techniques such as electron beam lithography can also be used to digitally produce the master hologram. The master hologram can preferably comprise glass, silicon, quartz, PTR glass, UV varnish, a photopolymer composite, and / or a metal such as nickel.

[0073] For the purposes of the invention, a "coupling element" is preferably a three-dimensional block of transparent material with a refractive index and dimensions configured to direct the exposure rays toward and / or away from the master holograms. In some embodiments, the coupling element may have the shape of a cuboid block, a (flat) plate, a pyramid, a prism, or a cylinder. In some embodiments, the coupling element is a general cylinder, i.e., it has a constant cross-section of any shape, e.g., square, polygonal, elliptical, or circular. The ends of the coupling element, which have the shape of the cross-section, may be referred to as the "base surface." The elongated surface of the coupling element, which lies between the two ends, may be referred to as the "lateral surface."In some embodiments, the shape of an axially rotatable vertical cylinder, preferably a circular cylinder, is preferred. In the sense of the invention, the shape of a rotatable cylindrical or prismatic coupling element, preferably a vertical cylinder, preferably a circular cylinder, can also be referred to as a “roller”. The coupling element can preferably be formed from an optical plastic or optical glass, wherein in preferred forms, preferred materials mentioned above with regard to the substrate body of the master element can be used.

[0074] It is preferred that the surface of the coupling element comprises glass, PC, TAC, or PMMA. The surface material can be in the form of a foil or a plate in the case of a multilayer coupling element. However, the surface material can also be the material of a monolithic coupling element and, for example, have a cuboid or cylindrical shape. In a preferred embodiment of the invention, the surface of the coupling element has an anti-reflective coating. This allows reflection losses on the surface of the coupling element to be largely eliminated.

[0075] The coupling element can be arranged in various orientations with respect to the master element, with the adhesive composite track preferably being positioned between the coupling element and the master element during exposure. Assuming a roller-shaped coupling element and a cuboid-shaped master element with a flat upper surface, the coupling element can, for example, be arranged above the master element. In this case, it may be preferred for the adhesive composite track to be applied between an upper surface of the master element and an underside of the roller-shaped coupling element (or vice versa). A reference beam can be directed onto a base surface of the coupling element, which is present as a cylindrical roller above the master element. The reference beam is refracted by the coupling element, and the refracted reference beam travels through the composite track to the master hologram.The refraction caused by the coupling element can, for example, be used to achieve the acute angle of incidence required for an edge-lit hologram. A master hologram can reflect the refracted reference beam, allowing an object beam from the master hologram to pass through the adhesive composite sheet. The object beam and reference beam interfere in the light-sensitive material of the composite sheet to create a reflection hologram. The adhesive properties of the adhesive composite sheet can effectively prevent optical losses or unwanted reflections at the interfaces between the adhesive composite sheet and a surface of the master or coupling element.

[0076] Adhesion of the optical adhesive film to the photosensitive composite web and / or another process component preferably comprises the presence of attractive forces between the optical adhesive film and the respective component. Preferably, the adhesion of the photosensitive composite web to the optical adhesive film is stronger than the adhesion of the photosensitive composite web to the surface of a master element or coupling element. For example, the adhesion of the optical adhesive film to the photosensitive composite web can be twice, three times, four times, or more than the adhesion of the optical adhesive film to a surface of a master or coupling element. In this way, the adhesion between the optical adhesive film and the photosensitive composite web can be considered permanent, while the adhesion of the adhesive composite web to an optical component can be considered temporary.Thus, the mechanical contact between the photosensitive composite web and the surface of the master or coupling element is stabilized by the presence of the optical adhesive film therebetween. A "permanent bond" between the optical adhesive film and the photosensitive composite web preferably prevents displacement or separation of the optical adhesive film from the photosensitive composite web during a replication process, preferably during the substantially complete replication process, in particular during an application step (on a master element or coupling element), an exposure step, and a detachment step (of the adhesive composite web from a master element or coupling element).In this sense, permanent adhesion between the optical adhesive film and the light-sensitive composite web can preferably be provided by a lamination and / or characterized by high peel forces as explained in more detail elsewhere herein.

[0077] Preferably, the temporary adhesion of the adhesive composite sheet to an optical component, such as the master element or a coupling element, is sufficient to prevent movement between the adhesive composite sheet and the optical component for the duration of an exposure step. Removal after exposure should preferably still be possible without causing deformation of the exposed composite sheet.

[0078] It may be preferred that a minimum pressure must be exerted on the adhesive composite sheet or on the optical adhesive film to create a sufficient adhesion between the optical adhesive film and the surface of the master element or coupling element. The required pressure may, for example, be at least 0.2 MPa, 1 MPa, 2 MPa, 5 MPa, 10 MPa (overpressure), or more. It may also be preferred that the optical adhesive film adheres sufficiently to the surface of the optical component merely through contact, without the application of additional pressure.

[0079] A "composite" within the meaning of the invention is preferably a multilayer material consisting of two or more different components with different physical properties that are bonded together at an interface. Preferably, the bond between the individual components is such that it cannot be separated by the application of slight force and is therefore considered permanent. Preferably, the layers of the composite web cannot be separated by a force of less than 1 N / cm, preferably less than 3 N / cm, more preferably less than 5 N / cm, more preferably less than 10 N / cm, or more preferably less than 50 N / cm. The composite preferably comprises at least one carrier film that provides the composite with sufficient tensile strength for movement through a replication device. The at least one carrier film can separate the optical adhesive film from a light-sensitive layer of the adhesive composite web.The photosensitive composite web preferably comprises at least one carrier film and at least one photosensitive layer comprising a photosensitive material. A "composite web" within the meaning of the invention is preferably a composite material with a length that is at least twice, preferably at least five times, and even more preferably at least twenty times its width. The thickness of the composite web is preferably adjusted to have a certain flexibility so that it can, for example, be partially wound around a roller or laminated to a surface. The composite web preferably has a thickness of up to 1000 μm, preferably up to 500 μm, particularly preferably up to 150 μm.

[0080] An "adhesive composite web" within the meaning of the invention is preferably a composite web comprising an optical adhesive film bonded to a photosensitive composite web in a layered structure. Preferably, the bond between the optical adhesive film and the photosensitive composite web is characterized by permanent adhesion, as explained above. In particular, the optical adhesive film should not be separated from the photosensitive composite web by slight force; rather, displacement or separation of the optical adhesive film from the photosensitive composite web should be effectively prevented during a replication process, in particular during an application step (on an optical component), an exposure step, and a detachment step (from the optical component).

[0081] A "low force" in this context is preferably less than the force required to detach the entire adhesive composite web from the surface of an optical component. This preferably means that a force used for the step of detaching the adhesive composite web from the surface of the master or coupling element is insufficient to separate the optical adhesive film from the photosensitive composite web. Furthermore, the adhesion between the optical adhesive film and the photosensitive composite web is preferably insensitive to tensile forces that occur during the transport of the adhesive composite web through a replication device, in particular through transport and / or deflection rollers. In this way, unintentional separation of the optical adhesive film from the photosensitive composite web can be avoided.Adequate adhesion between the optical adhesive film and the photosensitive composite web is preferably achieved by bonding them to form an adhesive composite web. In some embodiments, a sufficiently high peel force (particularly after exposure and detachment of the exposed composite web from a master element or coupling element) can bring about a desired separation of the optical adhesive film from the photosensitive composite web, preferably in a residue-free manner.

[0082] In a preferred embodiment of the invention, the replication method is carried out in a replication device. The replication device is preferably a device configured for replicating a hologram in a light-sensitive composite web and comprises one or more workstations for this purpose. A replication device, in particular an exposure station of the replication device, preferably comprises a radiation source for electromagnetic radiation (preferably a coherent light source, e.g., a laser) and a master element or a means for receiving such a master element. The replication device can preferably also comprise all other process components required for the respective embodiment of the method, such as, for example,Deflection rollers, laminating rollers, one or more coupling elements, one or more pressing elements, one or more detachment elements and / or one or more rewinders for removing one or more protective films.

[0083] Preferably, the replication device, in particular its exposure station, is at least partially enclosed by a light-tight housing, in particular such that no ambient light falls on the light-sensitive composite web. In some preferred embodiments, the replication device further comprises a (pre-)fixing station, which preferably contains one or more UV lamps, heating elements, and / or other curing agents. A laminating station for providing an adhesive composite web can be part of a replication device, in particular in the case of in-situ production of the adhesive composite web, or can be located upstream of the replication device.

[0084] In a preferred embodiment of the invention, the optical adhesive film in the provided adhesive composite web is laminated to the light-sensitive composite web. Laminating the optical adhesive film to the light-sensitive composite web advantageously ensures particularly strong adhesion between the optical adhesive film and the light-sensitive composite web. This adhesion preferably extends over a sufficient length to form the adhesive composite web. When the optical adhesive film adheres to the surface of an optical component, the light-sensitive composite web is therefore also (indirectly) connected as a component of the adhesive composite web with respect to the same optical component. Likewise, by applying the adhesive composite web to an optical component, an (indirect) connection can be created between the optical component (e.g.Master or coupling element) and the photosensitive composite web, the bond being mediated by the optical adhesive film. The laminated bond advantageously ensures that relative movement between the optical adhesive film and the photosensitive composite web is essentially avoided throughout the entire replication process. The lamination advantageously prevents unwanted detachment of the photosensitive composite web from the optical adhesive film, as this requires overcoming a peel force. The peel force can be adjusted based on the material of the optical adhesive film, the materials of the photosensitive composite web, and the lamination conditions such as pressure and temperature.

[0085] The adhesive composite web preferably comprises the optical adhesive film, which is present on the photosensitive composite web in such a way that a permanent bond or adhesion exists between the optical adhesive film and the photosensitive composite web during the hologram replication process. This preferably means that the optical adhesive film is sufficiently cohesive and adheres sufficiently strongly to the photosensitive composite web that it cannot be separated from the latter without significant force and / or without tearing the optical adhesive film or the photosensitive composite web. This means that detachment of the permanently bonded optical adhesive film from the photosensitive composite web is preferably not intended.

[0086] Such an adhesive composite web can be safely subjected to considerable forces without causing undesired separation of its layers or mutual displacement. This allows the adhesive composite web to be pulled through the stations of a device, e.g., with take-up reels and transport rollers, at high speed. Furthermore, the optical contact achieved by the adhesive composite web when applied to the surface of the optical component in question can have a greater extension, allowing for higher tolerances in synchronizing the movement of the adhesive composite web and that of a radiation source and / or other process component. Furthermore, the application of a wider range of exposure techniques is enabled, as the exposure beam does not have to be confined to a small area or tangent, which benefits from the good optical contact.The replicated hologram in the light-sensitive composite web can additionally benefit from the adhesive properties imparted to it by the optical adhesive film, allowing it to be efficiently integrated into a final product.

[0087] In preferred embodiments of the invention, the provision of an adhesive composite web comprises laminating the light-sensitive composite web with the optical adhesive film, preferably with the aid of a laminating station. Process steps of a laminating process, preferably using a laminating station, which are disclosed below with regard to laminating the light-sensitive composite web with the optical adhesive film, therefore preferably also apply to the process according to the invention, in particular with regard to a process step for providing the adhesive composite web.

[0088] A "lamination" in the sense of the invention is preferably a method for joining at least two layers of the same or different materials with the aid of pressure, wherein the pressure is preferably exerted by laminating rollers. The laminating rollers are preferably part of a laminating station. In addition, the temperature can be used to deform a layer and / or increase the adhesion of one layer to another. Preferably, the layers to be laminated are guided between two laminating rollers, wherein the laminating rollers press the layers together, for example with a pressure of at least 0.001 bar, preferably at least 0.01 bar, more preferably 0.1 bar (overpressure) or more. The pressure is preferably not more than 1 bar. Optionally, one or more of the laminating rollers are heated to a temperature between 20 - 200 °C, in particular 40 - 100 °C.In contrast to the application of the adhesive composite sheet to an optical component, for example by means of lamination, the lamination of the adhesive composite sheet is intended to achieve a substantially permanent bond between the optical adhesive film and the light-sensitive composite sheet.

[0089] In preferred embodiments, the optical adhesive film is configured such that it adheres to the photosensitive composite web substantially without any application of pressure and / or upon application of a pressure between 0.001 bar and 1 bar. In this way, high pressures can be avoided when the optical adhesive film is attached to the photosensitive composite web. This is advantageous because photosensitive materials are often viscoelastic. This means that they relax after a load and return to their original shape and thickness after a certain time. The preferred pressure can be particularly effectively ensured that relaxation of the photosensitive material has occurred completely by the time of replication. Any change in thickness during replication in the event of relaxation on longer time scales can be effectively avoided. Thus, particularly high-quality interference patterns orReceive hologram copies.

[0090] In a further preferred embodiment of the invention, the provision of an adhesive composite web comprises producing the adhesive composite web in situ. While the production preferably comprises laminating the optical adhesive film to the photosensitive composite web, alternative methods are also possible. In situ production preferably means that the adhesive composite web used in the replication process is continuously connected as a web to a production station from which the adhesive composite web is fed. In other words, there is preferably no interruption of the adhesive composite web between its production and its use in the replication process. The / nS / ft / production can take place inside or outside a replication device. This has the advantage that the properties of the adhesive composite web can be quickly adapted by adjusting the production materials and / or parameters.In a preferred embodiment of the invention, the provision of an adhesive composite web comprises laminating the light-sensitive composite web with the optical adhesive film by means of a laminating station, wherein the operating speed of the laminating station is coordinated with the operating speed of an exposure station of the replication device. This prevents the unexposed adhesive composite web from jamming. Any mechanical deformations that could occur in the event of a jam are effectively avoided. Such coordination of the operating speeds is particularly advantageous for combining in-situ production of the adhesive composite web with the replication process in a single production line.

[0091] In a preferred embodiment of the invention, the provision of an adhesive composite web comprises laminating the photosensitive composite web with the optical adhesive film by means of a laminating station, wherein the operating speed of the laminating station differs from the operating speed of an exposure station of a replication device. For example, it may be preferable to carry out the laminating process at a higher speed than a replication process, which is limited in time, in particular by an exposure step. In such a case, it may be advantageous to use a single laminating station to supply several exposure stations with the adhesive composite web. The adhesive composite web can, for example, be supplied intermittently to each exposure station, e.g., at the beginning of each replication series.After the laminating station has produced enough adhesive composite web to complete a replication series, the adhesive composite web can be separated from the laminating station, while a new adhesive composite web produced by the laminating station can be delivered to another exposure station.

[0092] In a preferred embodiment of the invention, one or more intermediate stations can be provided between a laminating station and an exposure station of the replication device, which (intermediately) store and / or further process the adhesive composite web. For example, a storage device can be provided between the laminating station and an exposure station of the replication device to compensate for a discrepancy between an output speed of the laminating station and an input speed required for the exposure station, wherein both the output speed and the input speed preferably relate to a web speed of the adhesive composite web.

[0093] In a preferred embodiment of the invention, the storage device can define a meandering path through which the adhesive composite web is guided. For this purpose, the storage device can, for example, provide deflection rollers. The adhesive composite web can preferably be guided through a meandering path by means of such deflection rollers, wherein the meandering path defines, for example, a path length of at least 50 cm, at least 100 cm, at least 500 cm, at least 1000 cm, or more. The path length of the temporarily stored adhesive composite web in the storage device can preferably be referred to as a "buffer length." For intermediate storage of the adhesive composite web, the storage device preferably comprises at least two, more preferably at least three, four, five, six, seven, eight, nine, ten, or more deflection rollers.The diameter of the deflection rollers can be selected for gentle storage of the adhesive composite web and / or for a sufficient buffer length. The diameter of a deflection roller can, for example, be at least 50 mm, at least 100 mm, at least 200 mm, at least 300 mm, at least 400 mm, at least 500 mm, or more. Preferably, the storage device is designed to be light-tight and / or connected to an exposure station in a light-tight manner to prevent unwanted exposure and / or optical interference.

[0094] The shear force exerted on the adhesive composite web can be reduced by selecting the number and / or dimensions of the deflection rollers. In contrast to the optical components, the deflection rollers must meet lower optical standards (e.g., a degree of polish) and can therefore be provided cost-effectively in desired formats. Advantageously, the use of the storage device also prevents the adhesive composite web from winding up before exposure. This is particularly advantageous for preventing unwanted wrinkling in the adhesive composite web and for preventing deformation or damage when using rollers with small radii. The risk of shifting of the layers or films relative to one another is also further reduced.

[0095] In a further preferred embodiment of the invention, the storage device is configured for a variable buffer length. For this purpose, it may be preferable to make the length of the meandering path of the adhesive composite web variable within the storage device. For example, deflection rollers can preferably be adjustable in their position, with the change in position of the deflection rollers causing a change in the buffer length and preferably being controllable depending on the throughput of the laminating station.

[0096] In alternative embodiments of the invention, the adhesive composite sheet is manufactured separately or upstream of a replication process. The adhesive composite sheet can thus be delivered to the replication device as a prefabricated product.

[0097] Preferably, the adhesive composite web is provided in the form of a web with a length of at least 50 cm, at least 100 cm, at least 200 cm, at least 500 cm, or more. The adhesive composite web can be provided in situ, as explained above, or prior to a replication process. Provision in web form can preferably also include provision of a photosensitive composite web and an optical adhesive film in roll form, which are preferably bonded in situ. The photosensitive composite web and optical adhesive film provided are preferably provided with protective films on at least one side, more preferably on both sides.

[0098] In a further preferred embodiment, the provision of an adhesive composite web comprises laminating the light-sensitive composite web with the optical adhesive film, wherein a provided optical adhesive film is provided with a protective layer, preferably with two protective layers, prior to lamination. The provided optical adhesive film is thus fed to one or more laminating rollers as a multi-layer structure. This is not only particularly advantageous for preventing unwanted adhesion of the optical adhesive film to process components, but also for mechanically stabilizing the optical adhesive film. By ensuring contact between the optical adhesive film and a protective film, which contributes to mechanical stability, the optical adhesive film can advantageously also be exposed to high shear forces and fed to the laminating rollers at high speeds without there being a risk of deformation and / or damage.Therefore, particularly soft materials can also be used advantageously for the optical adhesive film, especially in a single-layer structure.

[0099] It is particularly preferred that the optical adhesive film be provided on both sides with a first and second protective film. The second protective film is preferably provided on the side of the optical adhesive film intended for contact with the light-sensitive composite web during lamination. Such an arrangement imparts particularly high mechanical stability to the optical adhesive film both before and after lamination. This expands the possibilities for the types and thicknesses of optical materials that can be used for the optical adhesive film, especially in a single-layer structure.

[0100] In a further preferred embodiment of the invention, the second protective film is removed from the optical adhesive film immediately before lamination. Preferably, however, the first protective film remains on the optical adhesive film during lamination, so that the protective film can support mechanical stabilization of the optical adhesive film from the feed to the laminating rollers as well as during and after lamination.

[0101] In this context, the term "immediate" preferably means that no intermediate steps occur between the removal of the second protective film and the lamination step. Alternatively or additionally, this may mean that the interval or time between the removal of the second protective film and the lamination is short, preferably less than 100 mm, more preferably less than 50 mm, and / or less than 60 seconds, more preferably less than 20 seconds, even more preferably less than 5 seconds.

[0102] Since the lamination preferably takes place immediately after the removal of the second protective film, and the first protective film preferably remains on the optical adhesive film during lamination, the optical adhesive film is preferably never exposed and / or does not need to be guided without mechanical support. Deformation, damage, or contamination of the optical adhesive film can thus be particularly effectively prevented.

[0103] This technique can preferably also be used in the case of an adhesive composite web comprising two optical adhesive films, each of the two optical adhesive films preferably being provided with protective films on both sides. The protective films on the side of each optical adhesive film intended for contact with the photosensitive composite web are preferably removed immediately before the optical adhesive film is laminated to the photosensitive composite web. If the optical adhesive films are laminated to the photosensitive composite web simultaneously, the aforementioned protective films can be removed simultaneously. A wedge or a delaminating roller, for example, can be used to remove the protective films.

[0104] This principle can preferably also be applied to a light-sensitive composite web prior to lamination. The light-sensitive composite web can therefore preferably also be provided with protective films on both sides prior to lamination. One side (or both sides in the case of two optical adhesive films) of the light-sensitive composite web intended for contact with an optical adhesive film is preferably exposed prior to lamination by removing the protective film. The removal of one (or both) protective films can preferably take place immediately before lamination. In the event that the adhesive composite web resulting from the lamination comprises only one optical adhesive film, it is preferred that at least one protective film remains on the light-sensitive composite web after lamination, in particular to protect the adhesive composite web produced and / or for additional mechanical stabilization.

[0105] In a further preferred embodiment of the invention, the adhesive composite web comprises two optical adhesive films, preferably such that the light-sensitive composite web is enclosed between the optical adhesive films. Such an adhesive composite web can advantageously establish optical contact between the light-sensitive composite web and each of the master and coupling elements, so that the quality of hologram replication can be further improved.In a further preferred embodiment, in the provided adhesive composite web, the optical adhesive film on the light-sensitive composite web exhibits a peel force relative to the light-sensitive composite web and a peel force relative to the surface of the master element or coupling element, wherein the peel force of the optical adhesive film on the light-sensitive composite web is more than 1.2 times, preferably more than 1.5 times, the peel force relative to the surface of the master element or coupling element. This facilitates the detachment of the adhesive composite web from the surface of the master or coupling element without damaging the adhesive composite web or separating its layers.

[0106] In a further preferred embodiment, the optical adhesive film in the provided adhesive composite sheet has a peel force relative to the photosensitive composite sheet of more than 3 N / cm, preferably 5 N / cm or more. Such a peel force is advantageously suitable for providing an adhesive composite sheet that can establish optical contact between a long section of a photosensitive composite sheet and the surface of an optical component. At the same time, such an adhesive composite sheet has high integrity and can, for example, be peeled off from the surface of a master or coupling element at high speed and force without undesired separation of the layers.The adhesive composite web can thus be provided as a particularly robust unit that can be moved through a replication device even at high web speeds, without the forces that may occur during the process leading to separation and / or displacement of the layers relative to one another. The throughput of such a device can be maximized without compromising quality. For example, the throughput or the average web speed of the adhesive composite web can be preferably at least 20 m / min, preferably at least 50 m / min, and even more preferably at least 100 m / min, essentially without compromising quality.

[0107] The peel force of the optical adhesive film or one of its layers can be measured, for example, using a 180-degree peel test. The preferred method is ASTM D903, in which six inches of adhesive tape is applied to a clean substrate surface. The substrate is clamped. One free end of the adhesive tape is folded back 180 degrees and pulled with a force gauge. The force in Newtons required to detach each centimeter of the adhesive tape from the substrate is the peel force.

[0108] The peel force of an adhesive material with respect to a substrate surface preferably depends not only on the material composition of the adhesive material and the substrate, but also on the process conditions under which the adhesive material (in particular an adhesive material of the optical adhesive film) was applied to its carrier (in particular a carrier film of the photosensitive composite web). In the case of pressure-sensitive adhesive materials, for example, a stronger bond to a carrier layer can be achieved if, when applying the carrier layer, high pressure, temperature and / or additional crosslinking (e.g. by a chemical or electromagnetic curing process) of the adhesive material to the carrier layer is applied. Preferably, an additional adhesion promoter layer can be introduced in order to specifically increase the adhesion of the optical adhesive film to the photosensitive composite web.This effect can be exploited to improve the integrity of an adhesive composite web. At the same time, the adhesion of the optical adhesive film to the light-sensitive composite web can be adjusted differently from the adhesion of the adhesive composite web to another process component. This can facilitate the detachment of the adhesive composite web from the surface of the master or coupling element.

[0109] In contrast to the OCAs used in state-of-the-art finished products to create a permanent bond between product components, the preferred peel force for removing the adhesive composite sheet from a master element and a coupling element is low. This is particularly the case when the optical adhesive film of the adhesive composite sheet comes into direct contact with a surface of the master or coupling element. This means that the optical adhesive film adheres sufficiently to ensure optical contact during exposure, but at the same time can be easily removed without (even partially) tearing or leaving residues on a surface of the adjacent optical component. Furthermore, the optical adhesive film (and thus indirectly also the adhesive composite sheet) can advantageously be provided extremely thin.Higher mechanical strength for the optical adhesive film is not necessary to prevent damage or tearing when the adhesive composite sheet is removed from the respective surface. Furthermore, a low adhesive or peel force of the optical adhesive film reduces the accumulation of dust on the adhesive composite sheet, especially during processing times when the optical adhesive film is not in contact with a master element or coupling element and is not yet or no longer protected by a protective film.

[0110] In a further preferred embodiment of the invention, the adhesive composite web provided comprises a first protective film which is present on the optical adhesive film, preferably such that the optical adhesive film is enclosed between the first protective film and the light-sensitive composite web. The presence of the first protective film on the adhesive composite web preferably makes it possible to supply this adhesive composite web to the replication process as a non-stick unit in order to make the optical adhesive film insensitive to contaminants which could disrupt the optical contact and / or to facilitate the handling of the adhesive composite web. In particular, the adhesive composite web can be transported using various transport rollers without the need for an anti-stick coating. Furthermore, the adhesive composite web can be subjected to considerable pressure, such as that encountered, for example,required to laminate to a surface without the risk of leaving sticky residue on a laminating roller.

[0111] The first protective film of the adhesive composite web may preferably be the first protective film which is provided on the optical adhesive film and is not removed during lamination in order to protect the laminating roller from direct contact with the optical adhesive film and / or to support the mechanical stability of the optical film even during lamination.

[0112] The first protective film is preferably removed immediately before applying the adhesive composite sheet to the surface of the master element or the coupling element, wherein the removal of the first protective film can preferably be carried out using a wedge. Removing the first protective film immediately before applying the adhesive composite sheet to the surface of the master element or the coupling element makes it possible to minimize the duration of contact between the optical adhesive film and the environment in order to avoid contamination. Preferably, the first protective film is removed immediately before applying the adhesive composite sheet to the surface of the master element or the coupling element, provided that the adhesive composite sheet is applied to the surface with the side of the optical adhesive film facing it.By immediately removing the protective film before the optical film comes into contact with the surface of a master element or coupling element, a sufficiently high adhesion can be achieved by avoiding dirt particles or other wear on the adhesive surface.

[0113] In a further preferred embodiment of the invention, the provided adhesive composite sheet comprises a second protective film which is present on the photosensitive composite sheet, preferably such that the photosensitive composite sheet is enclosed between the second protective film and the optical adhesive film. Such a second protective film preferably protects the surface of the photosensitive composite sheet from damage, for example in order to reduce undesirable light scattering properties. Furthermore, the second protective film can protect the photosensitive composite sheet from undesirable embossing or adhesion to other process components, in particular if the photosensitive material would otherwise be uncovered on one side. Preferably, the second protective film is also removed immediately before application of the adhesive composite sheet to the surface of an optical component.The advantages of removing the first release liner immediately before applying the adhesive composite sheet to a surface also apply when a second release liner is present during preparation of the adhesive composite sheet and is removed immediately prior to the application step. This is particularly advantageous when the photosensitive composite sheet, in particular a photosensitive layer rather than an optical adhesive film, is adhered to the surface to which the adhesive composite sheet is applied. Using a wedge to remove the first or second release liner is an efficient passive means of performing this step. This is additionally gentle on the adhesive composite sheet, particularly because the release liner can be folded over the pointed end of the wedge and rolled up or recycled, so that the wedge does not need to directly contact the adhesive composite sheet.

[0114] Removing a protective film immediately before a subsequent step preferably means that there are no intermediate steps between the removal of the protective film and the subsequent step that affect the adhesive composite web. Preferably, the adhesive composite web is not subjected to any intermediate steps in which the surface of the adhesive composite web from which the protective film has been removed comes into contact with another process component. Thus, the newly exposed surface is preferably not brought into contact with additional deflection rollers or other components of the replication device.

[0115] The removal of a protective film immediately before a further step may also refer to a short period of time, in particular of at most one minute, preferably at most 30 seconds, even more preferably at most 10 seconds, between the removal of the protective film and the further step. Additionally or alternatively, the distance between the position at which the protective film is removed and the position at which the further step is carried out along the length of the adhesive composite sheet is preferably no more than 3 meters, more preferably no more than 1 m, even more preferably no more than 50 cm.

[0116] In a further preferred embodiment of the invention, the first protective film is removed after the adhesive composite web has been applied to the surface of the master element or the coupling element, but prior to exposure. This is particularly advantageous if the optical adhesive film of the adhesive composite web is oriented away from the surface to which the adhesive composite web is applied. In this way, the adhesive composite web can be subjected to an intermediate step, in particular to pressure being exerted on the adhesive composite web on the surface, without the optical adhesive film being directly touched. The adhesive composite web can be pressed, for example, by means of a laminating roller or a pressing element against the surface to which it is applied, wherein the laminating roller or the pressing element contacts the first protective film and not the optical adhesive film.By keeping the first protective film on the adhesive composite web during this step, contamination of the optical adhesive film and the leaving of residues on the laminating roller or pressure element are avoided. This will be explained in more detail with regard to specific embodiments.

[0117] In a further preferred embodiment of the invention, the optical adhesive film has a single-layer structure comprising precisely one adhesive layer, wherein the precisely one adhesive layer preferably consists of a single homogeneous material. With the preferred structure of the optical adhesive film, a carrier layer for the optical adhesive film can thus advantageously be dispensed with. The precisely one adhesive layer is preferably adhesive on both sides in order to mediate optical contact between the light-sensitive composite web and a master or coupling element. In this way, the optical adhesive film can be kept particularly thin and possible optical interfaces within the optical adhesive film can be avoided. Furthermore, the optical adhesive film can be particularly transparent, homogeneous and with low haze, so that an exposure beam traverses the adhesive film essentially without refraction or scattering.

[0118] On the one hand, the optical adhesive film can be kept extremely thin and transparent. On the other hand, the adhesive composite sheet comprising the optical adhesive film should have sufficient strength for various processes such as transport, application, and / or lamination, and should be able to be removed without residue without risk of damage. The tensile strength of the adhesive composite sheet is preferably at least 1 MPa, more preferably at least 2 MPa, more preferably at least 5 MPa, and more preferably at least 10 MPa or more. Such a tensile strength enables the adhesive composite sheet to be moved through a replication device at sufficient speeds.

[0119] In the case of a single-layer construction, the optical adhesive film preferably has a tensile strength (or "tear strength") of up to 5 MPa, more preferably up to 1 MPa, more preferably up to 0.5 MPa, even more preferably up to 0.1 MPa, with the tensile strength preferably being at least 0.1 kPa, more preferably at least 0.5 kPa. The optical adhesive film itself may thus meet much lower mechanical requirements compared to an optical adhesive film that is provided standalone and transported through a replication device.

[0120] For the purposes of the invention, the "tensile strength" is preferably the maximum mechanical tensile stress that the adhesive composite sheet (or a layer or film thereof) can withstand before its mechanical integrity is compromised, in particular before the adhesive composite sheet fails. The failure of a composite material preferably refers to the tearing of at least one, preferably all, layers, so that the composite sheet is separated. The tensile strength defines, in particular, the maximum force that causes the pre-laminated sheet, preferably first of one layer and subsequent layers, to tear. The tensile strength is preferably determined by a test method in accordance with ASTM D882 or DIN EN ISO 527.

[0121] In a further preferred embodiment of the invention, the optical adhesive film has a modulus of elasticity of less than 10 MPa, preferably less than 5 MPa, less than 1 MPa, less than 0.5 MPa, less than 0.1 MPa, or even less. The optical adhesive film can therefore be particularly elastic. This improves adhesion and provides a seamless contact, which can be achieved by pressing the optical adhesive film against a surface—despite any roughness. Such pressure advantageously causes the optical adhesive film to fill any gaps that may arise due to unevenness in the surface onto which the optical adhesive film is pressed. This achieves seamless optical contact, which significantly improves the quality of an exposure.At the same time, the low modulus of elasticity allows the optical adhesive film to return to its original shape and surface quality, especially its constant thickness, after the pressure is released.

[0122] Applying high pressure to materials with such low elastic moduli can be technically challenging, as the deformability of such materials makes them difficult to handle. However, combining the optical adhesive film with the photosensitive composite sheet to form an adhesive composite sheet surprisingly offers both the easy handling of a relatively inelastic photosensitive composite sheet and the high deformability of the optical adhesive film.

[0123] While a single-layer structure of the optical adhesive film as explained above is particularly preferred, in alternative embodiments, the optical adhesive film can also have at least one carrier layer. Such an optical adhesive film has a multilayer structure, with the carrier layer coated on at least one side with an adhesive layer. The carrier layer is preferably non-adhesive.

[0124] In a further preferred embodiment of the invention, the optical adhesive film comprises two adhesive layers, wherein preferably each adhesive layer is applied directly to the carrier layer.

[0125] In a further preferred embodiment of the invention, the optical adhesive film is bonded, preferably laminated, to the light-sensitive composite web along an entire longitudinal dimension of the provided adhesive composite web.

[0126] The longitudinal dimension of the provided adhesive composite web is preferably at least 10 mm, more preferably at least 50 mm, even more preferably at least 100 mm, even more preferably at least 500 mm, even more preferably at least 1000 mm or more. The longitudinal dimension of the provided adhesive composite web preferably corresponds to a direction of movement of the adhesive composite web through a replication device. The contact between the optical adhesive film and the light-sensitive composite web thus extends over a significant length and forms the adhesive composite web, which in particular preferably has a sufficient length to undergo a substantial part of the replication process as a composite. Such an adhesive composite web can preferably be applied over a significant portion of a surface in order to enable large-area, gap-free contact.The bonding of the optical adhesive film to the photosensitive composite web also advantageously eliminates the need for synchronizing different rollers that would otherwise transport these films separately. Furthermore, the continuous bonding of the optical adhesive film by lamination to the photosensitive composite web improves the load-bearing capacity of the adhesive composite web. This large-area bond allows the use of optical adhesive films with relatively low adhesive properties and / or relatively low tensile strength in the present invention. This may be due, among other things, to the fact that the large contact area between the optical adhesive film and the photosensitive composite web compensates for any low strength of the intermolecular forces between these layers per unit area.The greater contact thus supports a large overall attractive force between the layers, which, as explained, only allows their separation or displacement with considerable forces.

[0127] In a further preferred embodiment of the invention, the photosensitive composite web comprises one or more carrier films and a photosensitive layer, wherein at least one of the one or more carrier films is preferably arranged between the photosensitive layer and the optical adhesive film. By separating the optical adhesive film from the photosensitive layer by means of a carrier film, an adhesive composite web with particularly high tensile strength can be provided. At the same time, the materials of the optical adhesive film and the photosensitive layer can be particularly soft. This is advantageous if the photosensitive layer is to be deformed, e.g., to make it adhere to a surface and / or to impart a relief pattern to it.

[0128] Preferably, the carrier film - analogous to the optical adhesive film - has a transmission of at least 80%, wherein the transmission is preferably measured without Fresnel correction. The carrier film can be transparent to light - in particular in a wavelength range of 400 - 980 nm, preferably at least in the wavelength range 400 - 780 nm, and have minimal light scattering. Likewise, it can be preferred for the carrier film to have a haze of up to 1.5%, preferably up to 1%, more preferably up to 0.5%, more preferably up to 0.2%, and even more preferably up to 0.1%, in order to reduce light losses and desired reflections. Furthermore, it is preferred for the carrier film to have a brightness fluctuation between crossed polarizers of up to 30%, in particular up to 20%, across the width of the carrier film in order to reduce the optical losses caused by the carrier film.

[0129] The carrier film preferably comprises one or more of the following materials: polycarbonate (PC), polyethylene terephthalate (PET), polybutylene terephthalate, polyethylene, polypropylene, cellulose acetate, triacetate (TAC), cellulose hydrate, cellulose nitrate, cycloolefin polymers, polystyrene, polyepoxides, polysulfone, cellulose triacetate (CTA), polyamide, polymethyl methacrylate, polyvinyl chloride, polyvinyl butyral, polydicyclopentadiene, cycloaliphatic copolymers (COP), or mixtures thereof. The carrier layer particularly preferably comprises polycarbonate (PC), polyethylene terephthalate (PET), cellulose acetate, triacetate (TAC), polymethyl methacrylate, or mixtures thereof.

[0130] The carrier film preferably has a tensile strength of at least 0.5 MPa, more preferably at least 1 MPa, even more preferably at least 3 MPa, and even more preferably at least 5 MPa. This can contribute significantly to the high overall tensile strength of the adhesive composite sheet.

[0131] The thickness of the carrier film is preferably between 6 μm and 100 μm. It has been found that a thickness of at least 6 μm can provide the preferred tensile strength of at least 5 MPa for a wide variety of materials, while maintaining high transparency. The use of thinner carrier films also results in an overall thinner adhesive composite sheet. At greater thicknesses, however, the carrier film is even more tear-resistant. Up to a thickness of approximately 100 μm, particularly high transmission and low haze can still be ensured. The aforementioned parameter range has therefore proven particularly advantageous for a wide variety of applications.

[0132] Preferably, the photosensitive composite web encloses the photosensitive material between two transparent carrier films that have a similar refractive index to the photosensitive material. Preferably, the refractive index of the carrier films and the photosensitive material is between 1.4 and 1.6.

[0133] The preferred properties, in particular the materials and the optical and mechanical properties, of the carrier film of the light-sensitive composite web preferably apply analogously to a carrier layer of a multilayer optical adhesive film.

[0134] Since the carrier film of the photosensitive composite web preferably makes a significant contribution to the mechanical stability of the adhesive composite web, a separate carrier layer in the optical adhesive film can preferably be dispensed with. In this way, the adhesive composite web can comprise at least one carrier film, which is preferably part of the photosensitive composite web. In this way, the optical interfaces within the adhesive composite web can be minimized. The photosensitive material can be, for example, a photosensitive photopolymer or a dichroic gelatin with a preferred layer thickness between 1 and 500 pm. The photosensitive material can be photosensitive for the entire visible spectrum or wavelength-selective.

[0135] The layers or films of the photosensitive composite sheet can be permanently bonded to one another, particularly by lamination. The high peel strength and its preferred values ​​specified for the adhesive composite sheet therefore preferably apply analogously to the photosensitive composite sheet. This advantageously prevents unwanted separation of the layers or (carrier) films of the photosensitive composite sheet.

[0136] In a further preferred embodiment of the invention, the photosensitive composite web has only one carrier film, so that the photosensitive layer in the provided adhesive composite web can preferably be uncovered, at least temporarily (for example by removing a corresponding protective film), and can establish contact with an optical component (e.g., a master element or a coupling element). Preferably, in this embodiment, the photosensitive layer is in direct contact with a surface of the master element or the coupling element during exposure in order to establish optical contact by adhesion of the photosensitive layer to the surface. This arrangement eliminates the need for a further optical interface between the photosensitive layer and the surface of the master or coupling element.Additionally, a relief or structure can be transferred to the light-sensitive layer. The adhesive composite sheet can thus be provided with adhesive properties on both sides, using a minimal number of layers through which the electromagnetic radiation could be refracted for exposure.

[0137] In a further preferred embodiment of the invention, the light-sensitive layer faces the master element (ie, oriented toward the master element and preferably brought into direct or indirect contact with the master element), while the optical adhesive film faces a coupling element. In a further preferred embodiment of the invention, the light-sensitive layer faces a coupling element, while the optical adhesive film faces the master element.In other words, the adhesive composite web can preferably be oriented in any direction with respect to the master and coupling elements, wherein one of the orientations can be selected taking into account various factors, for example, depending on the shape of the master and coupling elements, the contact area between the adhesive composite web and each of the master and coupling elements, and / or whether one of the master and coupling elements has a surface relief that is preferably to be additionally transferred to the adhesive composite web. However, it is generally preferable for the photosensitive layer to be oriented towards the surface of the master element. This has proven to be more gentle on as yet unfixed interference patterns that arise in the photosensitive layer.

[0138] In a further preferred embodiment of the invention, a refractive index difference between the optical adhesive film and the surface of the master element and / or the coupling element is not more than 0.2, preferably not more than 0.1, and more preferably not more than 0.05. Alternatively, a refractive index difference between the optical adhesive film and a surface of the photosensitive composite web is not more than 0.2, preferably not more than 0.1, and more preferably not more than 0.05. This low refractive index difference offers a particularly smooth optical transition between the process components.

[0139] In a further preferred embodiment of the invention, the refractive index of the optical adhesive film lies between a refractive index of the surface of the master element and / or the coupling element and a refractive index of a surface of the photosensitive composite web. In this context, the term "between" preferably also includes the values ​​of the refractive indices of the adjacent process components themselves. This arrangement enables a smooth or interference-free transition of light rays between the various process components with minimal reflections and / or aberrations at interfaces.

[0140] As an illustrative example, the refractive indices, starting from a substrate body of a master element, can be chosen, for example, as follows.

[0141] Substrate body (from N-BK7): n e = 1 .519

[0142] Adhesive layer: n e = 1 .51

[0143] Master hologram (photopolymer layer): n e = 1,500

[0144] Master hologram (protective film): n e = 1 .485

[0145] Optical adhesive film (homogeneous adhesive layer): n e = 1 ,47 light-sensitive composite web (carrier film / photopolymer layer / carrier film) n e = 1.48 / 1.50 / 1.48

[0146] In the above example, the photosensitive composite sheet may, for example, comprise a carrier film made of triacetate (TAC), which has a refractive index of 1.48. Unless otherwise stated, the refractive indices mentioned in this text are measured according to ISO 489. If the photosensitive composite sheet comprises photopolymers and one or more TAC carrier films, the optical adhesive film preferably has a refractive index of 1.48 + / - 0.2, preferably + / - 0.1, more preferably + / - 0.05, so that the above values ​​allow a particularly smooth optical transition.

[0147] If the light-sensitive composite web comprises photopolymers and, for example, a PC carrier film, the optical adhesive film can preferably have a refractive index of 1.58 + / - 0.2, preferably + / - 0.1, more preferably + / - 0.05, so that a particularly smooth optical transition is also ensured.

[0148] In a further example, in which the light-sensitive composite web has a PC carrier film and is laminated with the optical adhesive film, wherein the optical adhesive film is in turn in contact with a TAC protective film of a master element during exposure, it may also be preferred that the refractive index of the optical adhesive film lies between that of PC and TAC, that is to say that the optical adhesive film preferably has a refractive index between 1.48 and 1.58.

[0149] The person skilled in the art knows materials which, based on the present teaching, enable the most continuous possible transition of the refractive index of the master element / coupling element and the adjacent surface of the light-sensitive composite web.

[0150] In a further preferred embodiment of the invention, the optical adhesive film, preferably as a single-layer structure in the form of an adhesive layer, has a transmittance of at least 80%, a haze of up to 2%, preferably up to 1%, more preferably up to 0.5%, more preferably up to 0.2% and even more preferably up to 0.1% and / or a brightness fluctuation between crossed polarizers of up to 30%, in particular up to 20%, across the width of the optical adhesive film. Minimizing the haze leads in particular to a reduction in the losses of the light used for exposure and to a reduction in unwanted reflections. By minimizing the brightness fluctuation between crossed polarizers, the optical losses caused by the adhesive layer are reduced and the quality of the replicated hologram is increased.These preferred values ​​preferably apply analogously to a multilayer optical adhesive film as well as to the entire adhesive composite web.

[0151] Transmittance is preferably measured without Fresnel correction. This preferably means that the measured transmittance is reduced by the magnitude of the two Fresnel reflections on the front and back of the material. Transmittance without Fresnel reflections is preferably approximately 8% higher than with an uncorrected method. Alternatively, the transmittance measurement can be performed at the Brewster angle using p-polarized light, since there is no interfacial reflection for p-polarized light at the Brewster angle. Transmittance preferably refers to the permeability of a medium to light waves without changing the wavelength. Percent transmittance is preferably the percentage of the intensity of the transmitted light compared to the light incident on the medium. Transmittance can be measured, for example, according to DIN EN ISO 13468.The optical adhesive film is therefore preferably transparent to light across the wavelength spectrum of 400–780 nm and exhibits minimal light scattering. The adhesive film is preferably colorless. However, a yellowish or grayish appearance is also acceptable. Such an adhesive film can be used for a wide variety of applications and is therefore preferable to a color-filtering adhesive layer that is red, blue, green, etc.

[0152] For the purposes of the invention, the term "haze" preferably refers to transmission haze, measured according to ASTM D1003. Haze preferably refers to the scattering of light upon passing through a transparent material, which can lead to the creation of additional disruptive interference fields and thus to additional but undesirable micro-optical structures in the replicated hologram. Haze can be inherent in the material, a result of the molding process, a consequence of the surface structure, or the result of environmental factors such as surface abrasion. Furthermore, haze can be caused by material inhomogeneities large enough to scatter visible light or electromagnetic radiation. In these cases, these are often differences in refractive index, microbubbles, vacuoles, and / or scattering particles or crystallites of the material itself in an amorphous environment.

[0153] The properties of the adhesive layer of the optical adhesive film can also be selected or adjusted as described below. The information regarding the preferred properties of the adhesive layer preferably applies regardless of whether the adhesive layer forms the optical adhesive film alone or is part of a multilayer optical adhesive film.

[0154] The adhesive layer preferably further comprises an adhesive material based on acrylates, epoxides, urethanes, EVOH (ethyl vinyl alcohol), rubber, silicone, or mixtures thereof. In particular, such materials can advantageously achieve a suitable peel strength, high transparency, sufficient elasticity, and mechanical strength. Furthermore, these materials can be easily formed into adhesive films of suitable thicknesses. Methods for producing adhesive materials based on the aforementioned materials are known to those skilled in the art. Such methods are described in the specialist literature, for example, in "Haftklebebänder, selbstklebende Folien und Etiketten" (H-adhesive Tapes, Self-Adhesive Films and Labels) by Georg Krüger, ISBN 3446422811.

[0155] The adhesive material preferably comprises at least one polymerizable resin, the polymerizable resin preferably being based on acrylic, EVOH, rubber, silicone, or mixtures thereof, and at least one polymerization agent. The polymerization agent is preferably selected to initiate the polymerization of the monomers present in the polymerizable resin. The polymerization agent preferably comprises a crosslinker and / or a crosslinking catalyst. Examples of monomers of a first type that are present in the polymerizable resin (e.g., acrylic resin) and can be polymerized by the polymerization agent are (meth)acrylic acid ester monomers. The polymerizable resin may also comprise monomers of a second type that have crosslinkable functional groups so that they can react with the monomers of the first type.Examples of such crosslinkable functional groups include hydroxyl groups, carboxyl groups, glycidyl groups, isocyanate groups, or a nitrogen-containing functional group, etc. Preferably, the crosslinker and / or crosslinking catalyst is selected taking into account the crosslinkable functional groups present in the polymerizable resin.

[0156] The adhesive strength or peel strength of the composition can be adjusted by adding a crosslinker of a suitable type and amount. Suitable components and methods for producing an adhesive material with the preferred optical and mechanical properties are known to those skilled in the art.

[0157] In preferred embodiments, the adhesive layer has a thickness of 20 μm to 250 μm, particularly 50 to 200 μm. The thickness can be adjusted depending on the desired properties of the optical adhesive film. For example, a lower thickness can increase the transparency of the optical adhesive film, while higher thicknesses can provide better compensation for any irregularities in the surfaces to be bonded and ensure increased mechanical strength. The aforementioned parameter range has proven particularly advantageous for a wide variety of applications.

[0158] In preferred embodiments, the adhesive material comprises a crosslinker. A crosslinker can advantageously reduce the peel force required to detach the optical adhesive film from the relevant surface of the master or coupling element. The crosslinker preferably also prevents adhesive residues from remaining on the surfaces. A small amount of a crosslinker in an adhesive composition can increase the adhesive strength of the adhesive up to a certain concentration. Above such a threshold concentration, for example, 0.2%, an increase in the crosslinker can reduce the adhesive strength. The proportion of crosslinker used can therefore advantageously adjust the adhesive properties of the adhesive material.

[0159] A "crosslink" is preferably a bond or a short sequence of bonds that connects one polymer chain to another. These bonds can be covalent or ionic, and the polymers can be either synthetic polymers or natural polymers (such as proteins). A "crosslinker" is preferably an additive that promotes the formation of such crosslinks between the polymers present in the adhesive material.

[0160] Examples of crosslinkers include isocyanate crosslinkers, epoxy crosslinkers, aziridine crosslinkers, metal chelate crosslinkers, or modified silanes such as aminobissilane. For example, a silane compound can be used as a crosslinker for acrylic resins.

[0161] Preferably, a crosslinker is present in the adhesive material at a concentration of at least 0.1 wt.%, preferably at least 0.2 wt.%, particularly preferably 0.2-0.9 wt.%. For the aforementioned concentrations, preferred peel forces of the optical adhesive film on various surfaces could be achieved in a preferred range of 0.3-1.6 N / cm. These preferred crosslinker concentrations are particularly advantageous for an acrylate-based crosslinker. However, the preferred concentration of a crosslinker can depend on its crosslinking activity, the base material, or the surface, as will be explained in more detail later in this text.

[0162] In a further preferred embodiment of the invention, the optical adhesive film has a peel force relative to the master element and / or the coupling element of less than 3 N / cm, preferably less than 1 N / cm. In preferred embodiments, however, the peel force of the adhesive layer of the optical adhesive film relative to the surface of the master element and / or the coupling element and / or a surface of the light-sensitive composite web is at least 0.01 N / cm, preferably at least 0.1 N / cm. It has been found that the aforementioned parameters for the peel force represent an optimum between easy, residue-free removal of the optical adhesive film from the respective component and the simultaneous elimination of an optical interface between the components. Furthermore, it has been found that these peel forces sufficiently suppress relative movements such as vibrations between the components.While prior art transparent adhesives can help improve the quality of hologram reconstruction, the optical adhesive film of the present invention improves the quality of replication. It is sufficiently adhesive to reduce optical losses at the interface between components, yet can also be removed, allowing the adhesive composite sheet to be moved from a master element or coupling element to another workstation.

[0163] In a further preferred embodiment of the invention, the adhesive composite web is provided with at least one protective film, preferably with two protective films, after exposure, wherein preferably a first protective film is applied to the optical adhesive film and a second protective film is applied to the photosensitive composite web. The at least one protective film preferably facilitates the separation of the exposed adhesive composite web from one or more transport rollers and / or from adjacent layers of the adhesive composite web if it is wound up or stacked as sheets. This improves the handling of the exposed adhesive composite web, in particular if it still comprises essential adhesive properties. The application of a protective film to each of the optical adhesive film and the photosensitive composite web results in the optical adhesive film remaining adhered to the photosensitive composite web after exposure.This is particularly gentle on the adhesive composite sheet, which does not need to be subjected to significant forces to separate its layers. Furthermore, the optical adhesive film can be protected from damage and contamination. This aids in the integration of the replicated hologram into a product through adhesion. Preferably, the optical adhesive film can also be used to contact a surface in a final product. Such integration can be achieved in an optically seamless manner, particularly due to the similarity or identity of the refractive indices of the optical adhesive film and the light-sensitive composite sheet.

[0164] In a further preferred embodiment of the invention, the optical adhesive film is removed from the adhesive composite web after exposure, wherein the optical adhesive film is preferably removed before one or more protective films are applied. The replicated hologram can thus be supplied as a thin layer that can be treated or further processed as required. This can be advantageous, for example, if a different, e.g. more strongly adhesive, adhesive layer is to be applied to the finished hologram in order to later integrate it into a product. Further processing steps can be facilitated by the presence of at least one non-sticky layer in the exposed photosensitive composite web, in particular a protective film and / or carrier film.

[0165] Some preferred embodiments of the invention can be grouped according to the geometric shapes of the optical components used. In a first group of some preferred embodiments, the adhesive composite sheet is applied to the outer surface of an optical component designed as a roller. In a second group of some preferred embodiments, the adhesive composite sheet is applied to a flat surface of an optical component.

[0166] In a preferred embodiment of the invention, the coupling element and / or the master element are mounted for axial rotation. In this embodiment, the coupling element and / or the master element preferably has the shape of a roller. The shape of the roller, in particular in combination with the axial rotatability, is particularly advantageous for creating a curved or gently angled contact surface with the adhesive composite web. Contact between the adhesive composite web and the outer surface of the roller can preferably be established continuously or stepwise by bringing the adhesive composite web into contact with the roller in the circumferential direction, which promotes the elimination of air gaps. In this way, particularly good optical contact can advantageously be established with little or no pressure.Furthermore, the axial rotatability of the master or coupling element enables synchronous rotation with the movement of an adhesive composite web attached to it. The master or coupling element can thus function mechanically similar to a deflection roller. This arrangement is therefore particularly suitable for a continuous process in which the adhesive composite web is guided over a rotating roller and is continuously exposed. Such co-movement of the adhesive composite web with the axially rotatable optical component is preferably achieved by sufficient friction between the adhesive composite web and the optical component, so that a movement of the optical component leads to a force transfer to the adhesive composite web, or vice versa. Reliable synchronization of the adhesive composite web with the rotating optical component is achieved without complex control techniques.In this way, high throughput can be achieved.

[0167] For the purposes of the invention, a "roller" is preferably a cylindrical geometric shape with a circular or elliptical cross-section. Particularly preferred is a so-called vertical (or straight) circular cylinder with a circular cross-sectional area. In other embodiments, however, it can also be an oblique circular cylinder or a vertical cylinder with an elliptical cross-sectional area. However, it can also be preferred for the roller to have a polygonal cross-section, in particular with an obtuse angle between various flat sides. For a roller with a polygonal cross-section, a polygon with at least 4, at least 5, at least 6, at least 7, at least 8, or more sides is preferably selected. The various flat surfaces of a polygonal roller can preferably have a narrow width between 2 mm and 20 cm, particularly preferably between 5 mm and 5 cm.Such a roller can function analogously to a cylindrical roller with a circular or elliptical cross-section.

[0168] The ends of the roller, which have the shape of the cross-section (preferably circular or elliptical), can be referred to as the "base surface." The elongated surface of the roller, located between the two ends, can be referred to as the "surface surface." The adhesive composite sheet preferably temporarily contacts the surface.

[0169] In a preferred embodiment of the invention, the adhesive composite web is guided over a lateral surface of the roller during exposure, wherein preferably a section of the adhesive composite web adheres to or at least comes into contact with a section of the lateral surface of the roller, wherein the section of the lateral surface corresponds to an opening angle a of at least 10°, preferably at least 20°, preferably at least 45°, preferably at least 60°, more preferably at least 90°, even more preferably at least 120°, even more preferably at least 180°.

[0170] "Moving" the adhesive composite web along the outer surface preferably means that the movement of the adhesive composite web and the outer surface is synchronous. Synchronization is preferably achieved by force transfer from an actively rotating roller to an adhesive composite web, or vice versa (through passive movement of the roller in response to the force transfer from an actively transported adhesive composite web). Force transfer preferably occurs via friction or adhesion between the process components. This is an efficient way to maintain both contact and synchronization between the process components. Alternatively or additionally, these can also be controlled separately.

[0171] Preferably, the adhesive composite web partially assumes the shape of the lateral surface of the roller during movement. Preferably, the adhesive composite web temporarily assumes the shape of the lateral surface over an extended area, for example, arcuately over a circular segment of a cylindrical master element with an opening angle of more than 20° or more, as preferably implemented above. This preferably means that the adhesive composite web not only contacts the lateral surface over a thin line width of less than 10 mm, preferably less than 1 mm, but also over a larger area. The preferred opening angles of more than 10°, preferably 20° or more, can lead to sufficient mechanical interaction between the adhesive composite web and the roller to more firmly fix the relative positions of these process components during exposure.In addition, a larger mechanical contact area of ​​the adhesive composite web on the roller can be used to directly fix the hologram before the adhesive composite web is detached from the roller. This can particularly effectively prevent the detachment or further transport of the adhesive composite web from introducing errors into the replicated holographic image.

[0172] The area of ​​optical contact between the adhesive composite web and the roller can preferably also be characterized by a contact length of the adhesive composite web with which the adhesive composite web has contact with the outer surface of the roller at a specific point in time. For example, contact lengths of more than 10 mm, more than 20 mm, more than 50 mm, more than 100 mm or more may be preferred. The radius and / or the shape of the roller, as well as the movement path of the adhesive composite web over the outer surface can be adapted in order to achieve desired lengths for optical contact between the adhesive composite web and the roller. In a further preferred embodiment of the invention, the section of the outer surface to which the adhesive composite web is applied corresponds to an opening angle α of up to 330°, preferably up to 270°, more preferably up to 180°, even more preferably up to 120°.Such a limitation of the opening angle a allows for easy detachment of the adhesive composite sheet from the roller, as a lower overall force is required. Limiting the opening angle can also be gentler on the interference patterns formed in the photosensitive material, as the photosensitive composite sheet can be subjected to lower shear forces.

[0173] In a further preferred embodiment of the invention, the adhesive composite web is pressed onto a lateral surface, wherein the adhesive composite web is pressed onto the lateral surface preferably before exposure, in order to bring a section of the adhesive composite web into optical contact with the lateral surface, in particular with the aid of one or more pressing elements, for example rollers and / or wedges. The applied pressure is preferably between 0.001 kPa and 5 MPa, in particular between 0.1 MPa and 5 MPa.

[0174] The one or more pressure elements can also be arranged around the lateral surface to define an opening angle a. The opening angle a can also be adjusted by the presence of a means for detaching the adhesive composite sheet from the lateral surface.

[0175] The use of pressure to apply the adhesive composite sheet to the outer surface is advantageous for increasing the adhesion between the optical adhesive film and the outer surface and particularly effectively preventing the undesirable occurrence of air gaps. The optical adhesive film can also advantageously compensate for any surface roughness of the roller's outer surface by being pressed against it. Furthermore, the application of pressure can reduce the adhesion requirements of the optical adhesive film, so that it exhibits little or no adhesive properties when no pressure is applied. This further prevents the accumulation of dust on the optical adhesive film.

[0176] The adhesive composite sheet can preferably also be applied to the surface of the roller without the additional application of pressure. In particular, the material and structure of the adhesive composite sheet can be configured such that it essentially immediately forms a gapless contact with the surface when brought into contact with it. This can be done analogously to the application of a self-adhesive transparent protective film to the screen of a mobile phone, whereby a large-area, gapless contact is established by pulling the film on without additional pressure.In a further preferred embodiment of the invention, the adhesive composite web is brought into contact with a flat surface of an optical component, in particular a cuboid, during exposure, wherein the roller acts as a coupling element and the flat surface is a surface of the master element or the roller acts as a master element and the flat surface is a surface of a coupling element.

[0177] In other words, the adhesive composite web, after it has preferably been applied to a roller (e.g., a coupling element) over an area as explained above, can be contacted with another optical component having a flat surface (preferably a master element) for the purpose of exposure. The shapes of the optical components used can preferably be selected independently of their function as a master or coupling element. This means that, in principle, both a combination of a roller-shaped coupling element with a flat-surface master element and a combination of a roller-shaped master element with a flat-surface coupling element are possible.

[0178] However, the combination of a roller-shaped coupling element with a master element having a flat surface is particularly preferred (see also Fig. 1). Such an arrangement is particularly gentle on the interference patterns formed in the light-sensitive composite web.

[0179] While the adhesive composite web can preferably be applied to a large area of ​​the roller's lateral surface, the lateral surface preferably contacts the flat surface via a smaller contact area, preferably essentially tangentially. Therefore, the contact between the adhesive composite web and the flat surface of an optical component (e.g., a cuboid master element) preferably occurs over a length of 0.5 - 10 mm.

[0180] In a further preferred embodiment of the invention, the adhesive composite web is (pre-)fixed before or during its detachment from the outer surface of a roller. This preferably means that radiation or heat from a fixing device is directed onto an exposed section of the adhesive composite web in order to render the exposed interference patterns insensitive to further optical and / or mechanical influences. This improves the quality of the exposed hologram and reduces the susceptibility to errors, especially because the adhesive composite web is exposed to virtually no optical or mechanical manipulation between exposure and fixing.

[0181] In a further preferred embodiment of the invention, the adhesive composite web is fixed after its detachment from the outer surface. This preferably takes place within the housing of a replication device, in particular an exposure station. Fixing after detachment preferably allows for the use of stronger fixatives, such as higher temperatures. Furthermore, space on the outer surface of the roller is saved.

[0182] In a further preferred embodiment of the invention, the replication process is carried out intermittently or semi-continuously. This preferably means that not all steps of the process take place simultaneously on different sections of the adhesive composite web, but that some steps take place in a repetitive manner on successive sections of the adhesive composite web. The start of a replication cycle is preferably signaled by the alignment of the roller at a first end of the planar surface, while an end of the replication cycle is preferably characterized by the roller reaching the second end of the planar surface and being lifted from the planar surface with a still-adhered, exposed section of the adhesive composite web. The alignment of the roller and its movement with respect to the planar surface can be achieved by a relative movement between the roller and the planar surface.After completion of a replication cycle, the roller with a fresh section of the adhesive composite web is preferably moved back to the first end of the flat surface to repeat the replication cycle. For this purpose, a cuboid-shaped optical component can be supported stationary while the cylindrical optical component is rolled over its surface from one end to the other. To repeat the rolling of the roller over the flat surface, the roller is preferably lifted together with the adhesive composite web and any pressing elements, returned to a first end of the flat surface of the cuboid-shaped optical component, and lowered back onto the flat surface. Alternatively, the cylindrical optical component can be rotated about its axis in a fixed position, while the cuboid-shaped optical component is translated relative thereto from one end to the other.To repeat the end-to-end movement of the cuboid optical component, it is preferably lowered from the roller and repositioned onto it. These alternatives can also be combined. Regardless of how the relative movement is realized, it is particularly preferred that no slippage occurs between the roller and cuboid optical components.

[0183] The application of fresh adhesive composite sheet to the surface can still be carried out simultaneously with the movement of the roller or the flat surface.

[0184] In a further preferred embodiment of the invention, the detachment of the adhesive composite web from the outer surface of a roller occurs essentially continuously, preferably by applying a tensile force to the adhesive composite web in order to move it away from the outer surface. This is preferably achieved by winding up the exposed (and preferably fixed) adhesive composite web or a component thereof. For example, a winder for the finished adhesive composite web can provide the necessary tensile force. Alternatively, this can also be achieved by a winder for the exposed photosensitive composite web.

[0185] In a further preferred embodiment of the invention, the adhesive composite web is moved continuously or intermittently through a replication device, in particular through an exposure station. Preferably, the average web speed of the adhesive composite web moving through the replication system is at least 0.5 m / min, more preferably at least 1 m / min, more preferably at least 5 m / min, even more preferably at least 20 m / min, at least 50 m / min, at least 100 m / min, or more.

[0186] In a further preferred embodiment of the invention, the master element and / or the coupling element has a flat surface, wherein the adhesive composite web is applied, preferably laminated, to the flat surface before exposure, preferably in order to establish an optical contact between the adhesive composite web and the flat surface.

[0187] In this embodiment, it is therefore preferred that a large-area contact of the composite web occurs on a flat surface. Such an embodiment is particularly suitable for replication processes that run semi-continuously and in which a change in the shape of the adhesive composite web, such as when the adhesive composite web is temporarily moved over the outer surface of a roller, is to be avoided. A semi-continuous replication process is preferably a process in which the adhesive composite web is not moved strictly continuously, but intermittently with a predetermined cycle time through a replication device, in particular through an exposure station. With this embodiment, contact of any size can be made, so that it is also suitable for large master holograms. Various exposure techniques, such as large-area exposure, can also be used.

[0188] In preferred embodiments, the application, preferably the lamination, of the adhesive composite web onto the flat surface is carried out in such a way that the adhesive composite web continuously covers a rigid flat surface, preferably of a master element and / or coupling element, so that in particular no gaps, bubbles or folds are present between the adhesive composite web and the flat surface. The application, preferably the lamination, thus provides a preferably gap-free, optical contact, wherein the connection does not have to be permanent, but should preferably also be detachable, for example after exposure, in order to detach the adhesive composite web from the master or coupling element. A "lamination" in the sense of the invention is preferably a method for connecting two process components. For embodiments of the lamination, one of the two components (e.g.a master element or a coupling element) preferably comprise a rigid, flat surface and are preferably fixed, while another of the two components (preferably the adhesive composite web) is preferably flexible and can be moved or applied over the rigid, flat surface for the purpose of lamination.

[0189] Optionally, the adhesive composite web is laminated to a flat surface using a laminating roller, which can preferably exert pressure. Lamination can take place at room temperature (20°C). Optionally, the laminating roller can also be heated to a lamination temperature above room temperature, for example, selected from a range of 20°C to 200°C, preferably 20°C to 100°C. The lamination (for example, a lamination pressure or lamination temperature) is preferably designed to create a gap-free, but preferably releasable, bond between the light-sensitive composite web and / or the optical adhesive film and a relevant surface (for example, a master element and / or coupling element).

[0190] In a further preferred embodiment of the invention, the provided adhesive composite web comprises a first protective film on the optical adhesive film, wherein the first protective film is removed only after the adhesive composite web has been applied, preferably laminated, to the flat surface of the master element or the coupling element. In this embodiment, the applied adhesive composite web is preferably oriented such that the optical adhesive film is not in contact with the flat surface. Instead, the optical adhesive film is preferably oriented away from the master element, optionally in the direction of a laminating roller and / or a coupling element.

[0191] By applying a first protective film to the adhesive composite web during lamination, lamination can advantageously be performed without direct contact between the laminating roller and the optical adhesive film. Undesired adhesion between the laminating roller and the optical adhesive film can be avoided, while the adhesion of the optical adhesive film is not compromised. Furthermore, the laminating roller can be kept free of residues. Furthermore, due to negligible adhesion between the first protective film and the laminating roller, the laminating roller can be operated at higher speeds and / or higher pressure without risking deformation.In a further preferred embodiment of the invention, the adhesive composite web is brought into contact with a lateral surface of a roller during exposure, wherein the flat surface is a surface of the master element and the roller functions as a coupling element or the flat surface is a surface of a coupling element and the roller functions as a master element.

[0192] In other words, after the adhesive composite sheet has been applied, preferably laminated, to a flat surface of an optical component (e.g., a master element), it can be brought into contact with another optical component in the form of a roller (preferably a roller-shaped coupling element) for the purpose of exposure. The shapes of the optical components used can preferably be selected independently of their function as a master or coupling element. This means that, in principle, both a combination of a flat master element with a roller-shaped coupling element and a combination of a roller-shaped master element with a flat coupling element are possible.

[0193] However, it is particularly preferred that the adhesive composite web is first applied to a flat surface of a master element. Subsequently, it is preferred that the adhesive composite web is contacted with a coupling element in the form of a roller for the purpose of exposure. In such an arrangement, it is also particularly preferred that the optical adhesive film is arranged between the photosensitive composite web and the roller. This allows the reflection beam used to expose the photosensitive composite web to pass through a minimal number of optical interfaces before interfering with the reference beam in the photosensitive material. Furthermore, the optical adhesive film can protect the photosensitive composite web from any mechanical influence of the roller moving over the adhesive composite web.

[0194] In a particularly preferred embodiment of the invention, the roller thus functions as a coupling element, while the flat surface is a surface of the master element. During exposure, the adhesive composite web is present between the flat surface of the master element and a lateral surface of the roller as a coupling element, so that the optical adhesive film preferably faces the roller. The roller is preferably rolled over the flat surface of the master element in order to direct electromagnetic radiation onto the master hologram during exposure. In this embodiment, optical contact is preferably established between the master element, the adhesive composite web, and the coupling element along a small-area contact, preferably a tangential section of the lateral surface.The optical contact between the roller-shaped coupling element and the adhesive composite web can, for example, have a length (along the length of the composite web) or line width between 0.5 - 50 mm, in particular 0.5 - 10 mm. The optical contact preferably moves along the adhesive composite web, while the coupling element is rolled over it. For this purpose, both the roller-shaped coupling element and the planar master element can be moved to achieve a corresponding relative movement, with the second case being preferred, as it simply enables continuous film transport through the replication system, which is significantly easier to manage in terms of system and control technology. The electromagnetic radiation is preferably directed at the moving area of ​​the optical contact.This can allow for great flexibility in the angle of incidence of the electromagnetic radiation, despite mechanical limitations in the positioning of the radiation source. Furthermore, the rolling motion of the coupling element, particularly in combination with a relatively small contact area along a thin line width of preferably less than 50 mm, allows the coupling element to be easily removed from the optical adhesive film, e.g., lifted, without any risk of deformation or damage to the adhesive composite sheet. This method therefore results in particularly high-quality holograms and is also particularly gentle on the material.

[0195] Regardless of the shape of the surfaces to which the adhesive composite web is applied, it is preferred that the adhesion of the composite web is adjusted such that detachment of the adhesive composite web from the surface is possible without damaging its mechanical integrity or any deformation of the exposed composite web. Detachment can be achieved by continuously winding the adhesive composite web after exposure, whereby it is continuously lifted from the surface of a roller. Detachment can also be achieved by separating optical components, such as the coupling element from the master element. Furthermore, detachment can be achieved by peeling and / or lifting the adhesive composite web from a surface, e.g., by means of a wedge and / or a roller.

[0196] In some preferred embodiments of the invention, pre-fixing or fixation of the replicated hologram in the light-sensitive composite sheet occurs before detaching the adhesive composite sheet from the optical component to which it is applied. In particular, the adhesive composite sheet is not moved after exposure and before (pre-)fixation. Alternatively, the adhesive composite sheet can also be fixed at any time after the exposure step, even after detachment of the adhesive composite sheet from the optical component.

[0197] In the following preferred embodiments, "fixing" preferably refers to a complete fixation, a pre-fixation, or a final step of the fixation of a photosensitive material that has already been pre-fixed. The fixation preferably cures the photosensitive material into which the hologram has been replicated, e.g., such that regions of the polymerized material can no longer move within a matrix. The fixation is preferably carried out using light in the wavelength range 340 to 800 nm, UV radiation, heat, and / or additional electromagnetic radiation.

[0198] For the purposes of the invention, "pre-fixing" is preferably a treatment of a light-sensitive material to reduce its sensitivity to further exposure by further coherent electromagnetic irradiation, particularly in the visible range, and / or mechanical influences. Pre-fixing can further be configured to adapt the material properties of the light-sensitive material, in particular by reducing its viscosity and / or by converting the material into a semi-solid or solid form. It can be preferred that pre-fixing is used on an already exposed light-sensitive layer of a replication composite in order to stabilize the light-sensitive material and prevent further exposure of gratings. The same means as for full fixation can be used for pre-fixing, in particular UV irradiation and heat treatment.It may be preferred that the process parameters used for pre-fixing, such as the intensity of UV radiation or the temperature of a heater, are adjusted to achieve the desired mechanical properties and / or the desired lower light sensitivity.

[0199] In a further preferred embodiment of the invention, the detachment of the adhesive composite web from the flat surface occurs intermittently. Preferably, the detachment occurs at the end of each replication cycle. Preferably, the start of a replication cycle is signaled by lowering a fresh section of the adhesive composite web onto the flat surface so that the adhesive composite web is brought onto the flat surface. The end of the replication cycle is preferably signaled by the roller reaching a second end of the flat surface after being moved from a first end to the second end. Once the replication cycle is complete, the roller can be lifted from the flat surface so that an air gap is created between the roller and the flat surface or adhesive composite web.The exposed (and optionally fixed) adhesive composite web can then be lifted from the flat surface by applying a tensile force with a vertical force component. This can be done, for example, with the aid of deflection rollers. In addition, a winder or take-up device for winding up the adhesive composite web or a component thereof can provide the necessary tensile force. This can preferably be adjusted so that the preferred average speeds of the adhesive composite web are achieved as described above. In a preferred embodiment of the invention, the adhesion of the optical adhesive film of the adhesive composite web to a surface of the master element or coupling element to which the adhesive composite web is applied is weaker than the adhesion of the optical adhesive film to the light-sensitive composite web.This preferably means that the adhesive composite web can be detached from the surface of the master or coupling element with such low force that tensions between the optical adhesive film and the light-sensitive composite web, or even separation of the optical adhesive film from the light-sensitive composite web, are avoided. Remaining of the optical adhesive film on the surface is also avoided. Instead, the adhesive composite web can be transported as a dimensionally stable unit to other processing stations for further processing.

[0200] In a further preferred embodiment of the invention, the photosensitive composite web is brought into contact with a surface of a master element or coupling element, wherein the adhesion of the photosensitive composite web to the surface of the master element or coupling element is weaker than the adhesion of the optical adhesive film to the photosensitive composite web. This preferably means that the detachment of the adhesive composite web from the surface of the master element or coupling element can be carried out with such low force that separation of the photosensitive composite web from the optical adhesive film is avoided. The leaving of parts of the photosensitive composite web, e.g., residues of the photosensitive material, on the surface is also avoided.

[0201] In a further preferred embodiment of the invention, the coupling element is in the form of a roller. The master element comprises a flat surface. The adhesion of the light-sensitive composite web to the flat surface of the master element is stronger than the adhesion of the optical adhesive film to a peripheral surface of the coupling element. Thus, rolling the coupling element over the flat surface of the master element advantageously does not result in the adhesive composite web adhering over a large area to the peripheral surface of the rolling coupling element, which also does not result in the adhesive composite web being unintentionally removed from the flat surface during exposure.

[0202] In a further preferred embodiment of the invention, the master element is in the form of a roller. The coupling element comprises a flat surface, and the adhesion of the light-sensitive composite web to a flat surface of the coupling element is stronger than the adhesion of the optical adhesive film to the outer surface of the master element. This provides corresponding advantages, in particular the prevention of unwanted detachment of the adhesive composite web from the uneven surface. The person skilled in the art can therefore select the required adhesion and thus the required materials of the optical adhesive film and / or light-sensitive composite web, the master element, or the coupling element based on these preferred boundary conditions. For example, the adhesion of the optical adhesive film to various process components can be adjusted by the choice of material.The material of the optical adhesive film is preferably selected so that it adheres more closely to the material of the adjacent carrier film of the photosensitive composite web than to the surface of an optical component. Furthermore, the manufacturing conditions of the adhesive composite web can be adjusted for optimal relative adhesion. This is preferably achieved by adjusting the pressure and / or temperature during lamination of the optical adhesive film to the photosensitive composite web. Furthermore, the process parameters during application of the adhesive composite web to a surface of an optical component, e.g., a lamination print, can be adjusted so as not to exceed the preferred boundary conditions.

[0203] Terms such as substantially, approximately, about, approximately, nearly, etc. preferably describe a tolerance range of less than ± 20%, preferably less than ± 10%, more preferably less than ± 5% and especially less than ± 1% and include the exact value.

[0204] Detailed description

[0205] In the following, the invention will be explained in more detail using examples and illustrations, without being limited to these.

[0206] Short description of the figures

[0207] Fig. 1 is a schematic representation of a replication method according to a first embodiment of the invention, wherein the adhesive composite web is applied to the outer surface of a coupling element.

[0208] Fig. 2 is a schematic representation of a replication process according to a second embodiment of the invention, wherein the adhesive composite sheet is applied to the flat surface of a master element.

[0209] Fig. 3 is a schematic representation of a preferred embodiment of a storage device which can be used between a laminating station and an exposure station.

[0210] Detailed Description of the Figures Figure 1 schematically shows a replication process according to a first preferred embodiment of the invention. The figure shows a pair of laminating rollers 16, which produce or provide the adhesive composite web 2 for the replication process.

[0211] For the production of the adhesive composite sheet 2, an optical adhesive film 6 is provided. This is provided with protective films on both sides. A protective film 8 is provided on a first side of the optical adhesive film 6. This serves to protect the optical adhesive film 6 before and during lamination. The protective film 8 also serves to protect the adhesive composite sheet 2 and is therefore referred to as the "first protective film of the provided adhesive composite sheet" 2. The optical adhesive film 6 is also provided with a protective film 28, which protects the optical adhesive film 6 from unwanted adhesion and contamination before lamination.

[0212] A photosensitive composite web 4 is also provided. This is also provided with protective films on both sides. A protective film 30 is present on a first side of the photosensitive composite web 4. Another protective film 10 is present on the second side of the photosensitive composite web 4. This protective film 10 serves to protect the second side of the photosensitive composite web 4 before and during lamination, as well as during the transport of the adhesive composite web 2 through a replication device. The protective film 10 is therefore also referred to as the "second protective film of the provided adhesive composite web."

[0213] Before laminating the optical adhesive film 6 with the light-sensitive composite web 4, the protective films 28 and 30 are removed using wedges 18. As an alternative to the wedges 18, delaminating rollers (not shown) can also be used. The outer protective films 8 and 10 remain on the adhesive composite web 2 to be provided. This prevents unwanted adhesion of the optical adhesive film 6 and the light-sensitive composite web 4 to the laminating rollers 16 and protects the provided adhesive composite web 2. At the same time, the laminating rollers 16 can create a strong bond between the optical adhesive film 6 and the light-sensitive composite web 4. The result of the lamination is an adhesive composite web 2 that is now provided on both sides with protective films 8 and 10. At the same time, the laminating rollers 16 can convey the adhesive composite web 2 towards the optical components 12, 14 used for exposure.

[0214] Next, the first protective film 8 of the adhesive composite web 2 is removed with the aid of a wedge 18. The adhesive composite web 2 is then guided over the surface of a roller-shaped coupling element 12 so that the optical adhesive film 6 comes into contact with its outer surface. To improve the adhesion and optical contact between the optical adhesive film 6 and the coupling element 12, a pressing element 26 in the form of a roller is provided. The pressing element 26 presses the adhesive composite web 2 against the outer surface of the coupling element 12. Shortly thereafter, or immediately before exposure, the second protective film 10 is also removed from the adhesive composite web 2. The adhesive composite web 2 is preferably applied to the coupling element 12 over a relatively large section of the outer surface of the coupling element 12, which corresponds to an opening angle α, wherein the angle α is an obtuse angle between 90° and 180°.

[0215] After applying the adhesive composite web 2 to the roller-shaped coupling element 12, the adhesive composite web 2 is further brought into contact with a flat surface of a master element 14. This can be achieved by a relative movement between the coupling element 12 and the master element 14, in particular by lowering the coupling element 12 onto the flat surface or by lifting the master element toward the coupling element 12. In the embodiment shown, the light-sensitive composite web 4 is aligned with the master element 14, while the optical adhesive film 6 is aligned with the coupling element 12.

[0216] By applying the adhesive composite web to the roller as the coupling element 12, there is extensive contact between the optical adhesive film 6 and a surface of the optical component, here the coupling element 12, while for the purpose of exposure, the light-sensitive composite web 4 only comes into direct contact with the planar master element 14 over a narrow length (0.5 - 50 mm, preferably 0.5 - 10 mm). This creates continuous optical contact between the master element 14, the light-sensitive composite web 4, the optical adhesive film 6, and the coupling element 12. Electromagnetic beams, in particular coherent light beams, are directed onto the coupling element 12, so that it directs the electromagnetic beams at a desired angle through the area of ​​continuous optical contact onto the master element 14.By using a reflection master hologram, the electromagnetic rays are diffracted across the region of continuous optical contact to the photosensitive composite web 4, where they interfere in a photosensitive material to replicate the hologram in regions.

[0217] In order to expose the entire master hologram and replicate it into the light-sensitive composite web 4, a relative movement between the coupling element 12 and the master element 14 is preferably provided. This can be achieved by moving the coupling element 12 and / or the master element 14.

[0218] According to a first embodiment, the coupling element 12, to which the adhesive composite web 2 is applied, rolls across the flat surface of the master element 14 from one end to the other. As soon as the optical contact area has moved from one end of the master element 14 to the other, a single hologram or a set of holograms of the master element 14 has been replicated, and the coupling element 12 is lifted from the flat surface of the master element 14 and moved back to the first end of the master element 14. A new replication cycle can be started.

[0219] According to a second embodiment, the coupling element 12 rotates about its axis without any longitudinal movement thereof in the replication device. Instead, during each replication cycle, the master element 14 is brought onto the outer surface of the coupling element, so that optical contact is established between the coupling element 12 and a first end of the master element 14, in particular a first end of the master hologram. Then, with synchronous rotation of the coupling element 12, the master element 14 is displaced in the longitudinal direction until optical contact is established between the coupling element 12 and a second end of the master element 14, in particular a second end of the master hologram. Thereafter, the master element 14 is released from the outer surface of the coupling element 12, and the replication cycle is repeated.

[0220] At the same time, the adhesive composite web 2 is continuously detached from both the master element 14 and the coupling element 12 during the replication cycle. Due to the sufficient tensile strength of the adhesive composite web, the detachment of the adhesive composite web 2 can be carried out with considerable force and at considerable web speed without the optical adhesive film 6 being separated from the light-sensitive composite web 4 and without the adhesive composite web 2 being damaged.

[0221] The adhesive composite web 2, which comprises the exposed, optionally also fixed, holograms, is then moved to a further station where a laminating roller 16 applies a protective film 22 to the photosensitive composite web 4. Furthermore, the optical adhesive film 6 is separated from the photosensitive composite web 4, thereby decoupling the components of the adhesive composite web 2 from one another. The separated optical adhesive film 6 is subsequently wound up and / or transported for further processing or reuse. Optionally, a further protective film 20 (not shown) is applied to the photosensitive composite web 4. The result of the process is a photosensitive composite web 4 comprising any number of copies of a replicated hologram and provided with protective films on one or two sides to facilitate its handling.

[0222] Preferably, the process shown in Fig. 1 is carried out intermittently, with the moving parts, including the laminating rollers 16, the coupling element 12 and / or the master element 14, and any winders and / or unwinders (not shown) for parts of the adhesive composite web 2 or the protective films 8, 10, 28, 30, 20, 22, moving in accordance with the replication cycle time, preferably in coordination with one another. The coordination of the movement of the various process components can be achieved with the aid of a control device.

[0223] Figure 2 schematically shows a replication method according to a second preferred embodiment of the invention. An optical adhesive film 6 is provided. The optical adhesive film 6 is coated on both sides with a protective film 8, 28. A light-sensitive composite web 4 is also provided, but in this embodiment, the light-sensitive composite web 4 is provided with the protective film 10 on only one side. Before the optical adhesive film 6 is laminated to the light-sensitive composite web 4, the protective film 28 is removed from the optical adhesive film 6.

[0224] The optical adhesive film 6 and the light-sensitive composite web 4 are then bonded together using the adhesive properties of the optical adhesive film 6 and the laminating rollers 16. This creates an adhesive composite web 2 that can be guided toward the master element 14 and the coupling element 12.

[0225] Between the lamination and a step in which the adhesive composite sheet 2 is applied to a flat surface of the master element 14, the second protective film of the provided adhesive composite sheet 10 is removed, while the first protective film of the provided adhesive composite sheet 8 is retained. The adhesive composite sheet 2 is applied to the flat surface of the master element 14 such that the photosensitive composite sheet is in direct contact with the flat surface.

[0226] To establish a material-to-material contact between the adhesive composite web 2 and the flat surface of the master element 14, a laminating roller 24 is preferably used. The presence of the first protective film 8 on the adhesive composite web 2 during the lamination step protects the laminating roller 24 from undesired adhesion to the optical adhesive film 6. No adhesive residue remains on the laminating roller 24, nor can the laminating roller 24 cause undesired pulling or lifting of the adhesive composite web. Instead, the laminating roller 24 is rolled over the flat surface of the master element 14 to temporarily apply the photosensitive composite web 4 to the surface of the master element 14 and eliminate any air gaps between the photosensitive composite web 4 and the master element 14.

[0227] After lamination, the first protective film 8 is removed from the adhesive composite web 2, exposing the optical adhesive film 6. The adhesive composite web 2 is then contacted with a roller-shaped coupling element 12, which is rolled over the master element 14, in particular from one end of the master element 14 to the other during a replication cycle. The adhesive composite web 2 preferably adheres sufficiently to the outer surface of the coupling element 12 to create optical contact between the light-sensitive composite web 4 and the coupling element 12. However, the adhesion between the adhesive composite web 2 and the coupling element 12 is preferably sufficiently weak that the coupling element 12 does not pull, shift, or detach the adhesive composite web 2 from the master element 14 when the coupling element 12 is rolled over the master element 14 or lifted off it.

[0228] Due to the lamination, the adhesive composite web 2 is preferably in contact with the flat surface of the master element 14 over a larger area. The contact between the adhesive composite web 2 and the outer surface of the coupling element 12, however, is limited to a smaller section of the outer surface (preferably approximately 0.5 - 50 mm of a length of the adhesive composite web 2). In this way, an optical contact is established between the master element 14, the light-sensitive composite web 4, the optical adhesive film 6, and the coupling element 12 along the contact surface between the coupling element 12 and the adhesive composite web 2. An electromagnetic beam, in particular a coherent light beam (e.g., from a laser), is then directed onto the coupling element 12 such that it is refracted onto the master hologram at a desired angle.By using a master hologram in the form of a reflection hologram in the master element 14, the electromagnetic beam is then diffracted toward the light-sensitive composite path 4, where it interferes with the reference beam in a light-sensitive material, creating an interference pattern. The electromagnetic beam preferably follows the coupling element 12 as it moves across the master element 14, so that the entire master hologram is copied in the light-sensitive composite path 4.

[0229] After an exposure cycle, the photosensitive composite web 2 may also be subjected to a pre-fixing or fixing step (not shown), which may be performed before the adhesive composite web 2 is detached from the master element 14, for example, to prevent the introduction of image defects. A UV lamp and / or a heat source may be used for this purpose.

[0230] The adhesive composite web 2 is then removed from the flat surface of the master element 14. For this purpose, the coupling element 12 is preferably lifted from the surface of the master element 14 and a tensile force is exerted on the adhesive composite web 2 in order to lift it from the master element 14 and transport it further. The tensile force can be generated, for example, by a winder or take-up device with which the adhesive composite web 2 or parts thereof (e.g., only the photosensitive composite web 4) are wound up. After the adhesive composite web 2 has been removed from the surface of the master element 14, it is provided with a protective film 22 on the exposed side of the photosensitive composite web 4. The optical adhesive film 6 is then separated from the photosensitive composite web 4. This results in a photosensitive composite web 2 comprising replicated holograms and at least one protective film 22.

[0231] Figure 3 schematically shows a preferred embodiment of a storage device 32 provided with a light-tight housing. The storage device 32 can be arranged between a laminating station, in particular the laminating rollers 16, and an exposure station comprising the master and coupling element. The illustrated storage device 32 comprises a plurality of deflection rollers 34, which define a meandering path through which the adhesive composite web 2 is guided. This allows the adhesive composite web 2 to be temporarily stored before the exposure steps in order to compensate for any discrepancy between the output speed of the laminating station and the input speed required by an exposure station. Optionally, the deflection rollers 34 can be moved closer or further apart in order to adjust the length of the adhesive composite web 2 that is temporarily stored.

[0232] REFERENCE SYMBOL

[0233] 2 adhesive composite membranes

[0234] 4 light-sensitive composite sheet

[0235] 6 optical adhesive film

[0236] 8 first protective film of the provided adhesive composite sheet

[0237] 10 second protective film of the provided adhesive composite sheet

[0238] 12 coupling element

[0239] 14 Master element

[0240] 16 Laminating roller

[0241] 18 wedge

[0242] 20 first protective film of the exposed adhesive composite sheet

[0243] 22 second protective film of the exposed adhesive composite sheet

[0244] 24 Laminating roller

[0245] 26 Pressure element

[0246] 28 second protective film of the optical adhesive film

[0247] 30 first protective film of the light-sensitive composite sheet

[0248] 32 Storage device

[0249] 34 Deflection roller a Opening angle of the outer surface of a roller on which the adhesive composite web is applied.

Claims

PATENT CLAIMS 1 . A method for replicating a hologram in a photosensitive composite web (4) comprising the following steps: a. providing a master element (14) comprising a substrate body and at least one master hologram, b. providing an adhesive composite web (2) comprising a photosensitive composite web (4) and an optical adhesive film (6), c. applying the adhesive composite web (2) to a surface of the master element (14), d. exposing the master element (14) to replicate the at least one master hologram in the photosensitive composite web (4), wherein the optical adhesive film (6) mediates optical contact between the photosensitive composite web (4) and the master element (14) or between the photosensitive composite web (4) and a coupling element (12), and e. detaching the adhesive composite web (2) from the master element (14).

2. A method for replicating a hologram in a light-sensitive composite web (4), comprising the following steps: a. providing a master element (14) comprising a substrate body and at least one master hologram, b. providing a coupling element (12), c. providing an adhesive composite web (2) comprising the light-sensitive composite web (4) and an optical adhesive film (6), d. applying the adhesive composite web (2) to a surface of the coupling element (12), e. aligning the coupling element (12) to the master element (14) so ​​that the adhesive composite web (2) comes into temporary contact with the master element (14), f.Exposing the master element (14) using the coupling element (12) to replicate the at least one master hologram in the light-sensitive composite web (4), wherein the optical adhesive film (6) mediates optical contact between the light-sensitive composite web (4) and the coupling element (12) or between the light-sensitive composite web (4) and the master element (14), and g. Detaching the adhesive composite web (2) from the coupling element (12).

3. Method according to one of the preceding claims, characterized in that the optical adhesive film (6) of the adhesive composite web (2) is laminated on the light-sensitive composite web (4), preferably in such a way that a permanent connection is present between the optical adhesive film (6) and the light-sensitive composite web (4) during the implementation of the method for replicating the hologram.

4. Method according to one of the preceding claims, characterized in that in the provided adhesive composite web (2) the optical adhesive film (6) on the light-sensitive composite web has a peel force with respect to the light-sensitive composite web (4) and a peel force with respect to the surface of the master element (14) or coupling element (12), wherein the peel force of the optical adhesive film (6) on the light-sensitive composite web is more than 1.2 times, preferably more than 1.5 times the peel force with respect to that of the surface of the master element (14) or coupling element (12).

5. Method according to one of the preceding claims, characterized in that the provided adhesive composite sheet (2) comprises a first protective film (8) which is present on the optical adhesive film (6), wherein the first protective film (8) is preferably removed immediately before application of the adhesive composite sheet (2) on the surface of the master element (14) or the coupling element (12).

6. Method according to one of the preceding claims, characterized in that the coupling element (12) and / or the master element (14) is mounted so as to be axially rotatable and has the shape of a roller.

7. Method according to the preceding claim, characterized in that the adhesive composite web (2) is guided over a circumferential surface of the roller during the exposure, wherein preferably a section of the adhesive composite web (2) adheres to a section of the circumferential surface of the roller, wherein the section of the circumferential surface has an opening angle (a) of at least 20°, preferably at least 45°, preferably at least 60°, more preferably at least 90°, even more preferably at least 120°, even more preferably at least 180°.

8. Method according to the preceding claim, characterized in that the section of the lateral surface corresponds to an opening angle (a) of up to 330°, preferably up to 270°, more preferably up to 180°, even more preferably up to 120°.

9. Method according to one of the preceding claims 6 - 8, characterized in that the adhesive composite web (2) is pressed onto a lateral surface, wherein pressing of the adhesive composite web (2) onto the lateral surface preferably takes place before exposure in order to bring a section of the adhesive composite web (2) into optical contact with the lateral surface, in particular with the aid of one or more pressing elements (26), for example rollers and / or wedges.

10. Method according to one of the preceding claims 6 - 9, characterized in that the adhesive composite web (2) is brought into contact with a flat surface of an optical component, in particular a cuboid, during the exposure, wherein (i) the roller acts as a coupling element (12) and the flat surface is a surface of the master element (14) or (ii) the roller acts as a master element (14) and the flat surface is a surface of a coupling element (12).

11. Method according to one of the preceding claims 1 to 5, characterized in that the master element (14) and / or the coupling element (12) has a flat surface, wherein the adhesive composite web (2) is applied, preferably laminated, to the flat surface before exposure, preferably in order to establish an optical contact between the adhesive composite web (2) and the flat surface.

12. Method according to the preceding claim, characterized in that the provided adhesive composite sheet (2) comprises a first protective film (8) on the optical adhesive film (6), wherein the first protective film (8) is only applied after the Applying, preferably laminating, the adhesive composite sheet (2) to the flat surface of the master element (14) or the coupling element (12).

13. Method according to one of the preceding claims 11 or 12, characterized in that the adhesive composite web (2) is brought into contact with a lateral surface of a roller during the exposure, wherein (i) the flat surface is a surface of the master element (14) and the roller acts as a coupling element (12) and or (ii) the flat surface is a surface of a coupling element (12) and the roller acts as a master element (14).

14. Method according to one of the preceding claims 11 - 13, characterized in that the flat surface is a surface of the master element (14) and the roller functions as a coupling element (12), wherein the adhesive composite web (2) is present between the flat surface of the master element (14) and the roller during exposure, so that the optical adhesive film (6) faces the roller, wherein the roller is preferably rolled over the flat surface of the master element (14) in order to direct electromagnetic radiation onto the master hologram.

15. Method according to one of the preceding claims, characterized in that the optical adhesive film (6) is laminated along an entire longitudinal dimension of the provided adhesive composite web (2) on the light-sensitive composite web (4), wherein the longitudinal dimension is preferably at least 10 mm, more preferably at least 50 mm, even more preferably at least 100 mm, even more preferably at least 500 mm, even more preferably at least 1000 mm or more, wherein the longitudinal dimension of the provided adhesive composite web (2) preferably corresponds to a direction of movement of the adhesive composite web (2) through a replication device.

16. Method according to one of the preceding claims, characterized in that the photosensitive composite web (4) comprises one or more carrier films and a photosensitive layer, wherein at least one of the one or more carrier films is preferably arranged between the photosensitive layer and the optical adhesive film (6).

17. Method according to the preceding claim, characterized in that the photosensitive composite web (4) has only one carrier film, wherein the photosensitive layer is preferably in direct contact with a surface of the master element (14) or the coupling element (12) during exposure in order to establish an optical contact by adhesion of the photosensitive layer to the surface.

18. Method according to the preceding claim, characterized in that the light-sensitive layer faces the master element (14), while the optical adhesive film (6) faces a coupling element (12).

19. Method according to one of the preceding claims, characterized in that the adhesive composite web (2) is provided after exposure with at least one protective film (20), preferably with two protective films (20, 22), wherein preferably a first protective film (20) is applied to the optical adhesive film (6) and a second protective film (22) is applied to the light-sensitive composite web (4).

20. Method according to one of the preceding claims 1 - 18, characterized in that the optical adhesive film (6) is removed from the adhesive composite web (2) after exposure, wherein preferably the removal of the optical adhesive film (6) takes place before application of one or more protective films (20, 22).

21. Method according to one of the preceding claims, characterized in that the optical adhesive film (6) has a single-layer structure comprising exactly one adhesive layer and preferably consists of a single homogeneous material.

22. Method according to one of the preceding claims, characterized in that a refractive index difference between the optical adhesive film (6) and the surface of the master element (14) and / or the coupling element (12) is not more than 0.2, preferably not more than 0.1 and more preferably not more than 0.05 and / or a refractive index difference between the optical adhesive film (6) and a surface of the light-sensitive composite web (4) is not more than 0.2, preferably not more than 0.1 and more preferably not more than 0.

05.

23. Method according to one of the preceding claims, characterized in that a refractive index of the optical adhesive film (6) lies between a refractive index of the surface of the master element (14) and / or the coupling element (12) and a refractive index of a surface of the light-sensitive composite web (4).

24. Method according to one of the preceding claims, characterized in that the optical adhesive film (6) has a peel force relative to the master element (14) and / or the coupling element (12) of less than 3 N / cm, preferably less than 1 N / cm.

25. Method according to one of the preceding claims, characterized in that the optical adhesive film (6) has a transmission of at least 80%, a haze of up to 2% and / or a brightness variation between crossed polarizers of up to 30% across a width of the optical adhesive film (6).

26. Method according to one of the preceding claims, characterized in that the optical adhesive film (6) comprises an adhesive material based on acrylates, epoxides, urethanes, EVOH (ethyl vinyl alcohol), rubber or silicone, wherein the optical adhesive film (6) preferably has a thickness of 50 pm to 250 pm.

27. Method according to one of the preceding claims, characterized in that an adhesion of the optical adhesive film (6) of the adhesive composite web (2) to a surface of the master element (14) or coupling element (12) to which the adhesive composite web (2) is applied is weaker than an adhesion of the optical adhesive film (6) to the light-sensitive composite web (4).

28. Method according to one of the preceding claims, characterized in that the light-sensitive composite web (4) is applied to a surface of a master element (14) or a coupling element (12), wherein an adhesion of the light-sensitive composite web (4) to the surface of the master element (14) or of the coupling element (12) is weaker than an adhesion of the optical adhesive film (6) to the light-sensitive composite web (4).

29. Method according to one of the preceding claims, characterized in that the optical adhesive film (6) has a tear strength of up to 5 MPa, more preferably up to 1 MPa, more preferably up to 0.5 MPa, even more preferably up to 0.1 MPa, wherein the tear strength is preferably at least 0.1 KPa, more preferably at least 0.5 KPa.

30. Method according to one of the preceding claims, characterized in that the optical adhesive film (6) has a modulus of elasticity of less than 10 MPa, preferably less than 5 MPa, less than 1 MPa, less than 0.5 MPa, less than 0.1 MPa or even less.

Images