Method and device for producing a hologram for a security element and method for producing a valuable or security document

Description

[0001] The invention relates to a method and a device for producing a hologram for a security element and to a method for producing a valuable or security document. background

[0002] Security elements are used to protect security or valuable documents against forgery or copying. Holograms are one type of security element. Security elements often also contain individualizing information, such as serial numbers, ID numbers, biometric data, images (passport photos), etc. These can be provided in plain text or image form, or be optically encoded or machine-readable.

[0003] The basic procedure for producing holograms is described, for example, in document EP 0 896 260 A2. The basic principles are briefly explained below. First, a holographic master with a master hologram is produced. The holographic master is then positioned behind a holographic recording material. Coherent light, such as laser light, is irradiated onto the side of the holographic recording material facing away from the holographic master, typically with a defined wavelength and angle of incidence, depending on the holographic pattern to be reconstructed from the holographic master.It penetrates the holographic recording material and is diffracted and / or reflected by the master, creating the hologram through interference with the incident light. The hologram is imaged in the holographic recording material and stored in the holographic recording material through photochemical or photophysical processes. The holographic master can be designed to be sensitive to multiple wavelengths and diffract them accordingly. Arrangements other than the one described can also be used to produce holograms. Document EP 0 375 185 A2 also describes the inscription of holograms into a holographic recording material.

[0004] For example, volume holograms are well known. This is a hologram in which the structures formed and imaged by interference extend from one surface of the hologram or holographic recording material into it. These structures can be considered as multiple Bragg planes within the material. A volume hologram therefore exhibits high wavelength selectivity, meaning it can only be reconstructed using the spectral color with which it was exposed.

[0005] To individualize holograms, the coherent light can be modulated using a so-called spatial light modulator. This imprints an individualized pattern on the hologram. Digital projectors that work with spatial light modulators in the form of liquid crystal displays (LCDs) are known in practice. Their functionality is similar to the projection of a slide, for example, with the spatial light modulator taking the place of the slide. Furthermore, digital projectors are known that incorporate a DMD (Digital Micro Mirror Device) as a spatial light modulator. The use of a spatial light modulator in the form of a Digital Micro Mirror Device (DMD) for marking objects is known from the literature reference DE 2005 054 396 A1.

[0006] Document WO 2007 / 014317 A2 discloses a method and apparatus for mass production of reflection holograms. This method involves copying a master, which, for example, includes a counter for individually numbering the holograms produced sequentially. If the master is colored, it can also be copied in color by irradiating it with multicolored laser light. The different color information is stored in the same memory area of ​​the hologram.

[0007] From JP-06-118863 A a method for producing a colored Lipmann hologram is known.

[0008] Document WO 2017 / 109 119 A1 discloses a method for integrating a hologram into a security document body comprising a lamination body, the method comprising the following steps: providing a hologram film with a carrier substrate layer and a photo layer and providing further substrate layers, carrying out a lamination to form the lamination body, the hologram film being collected together with the further substrate layers to form a substrate layer stack and being joined together with the further substrate layers in a lamination process to form the lamination body.

[0009] Document DE 10 2007 042 386 A1 discloses a method for producing colored, individualized holograms that can be used as security elements for security and / or valuable documents. The method involves generating light of several different colors, spatially modulating the light individually and separately by color, optically guiding the modulated light such that the light is at least partially diffracted and / or reflected on a holographic master, and superimposed on the modulated, non-diffracted and / or reflected light in a holographic recording material, and recording the multicolored, individualized hologram. The light is simultaneously modulated by color using several spatial light modulators.Each of the multiple colors is assigned its own spatial light modulator, and the multiple single-color modulated light beams (6"-8") of the multiple colors are collinearly combined to form a multicolor, color-separated, individually modulated exposure light beam before being diffracted and / or reflected on the holographic master and superimposed in the holographic recording material, so that exactly one of the multiple colors is assigned to each of the pixels of the individualized hologram.

[0010] The document DE 10 2012 216219 A1 describes a master for the production of a volume reflection hologram individualized in an individualizable area, comprising a carrier, at least one diffraction structure which is arranged on the carrier or is formed therein and covers an individualizable area, wherein the at least one diffraction structure reflects coherent light of a wavelength which impinges on the diffraction structure from a predetermined direction of incidence in a predetermined direction of emergence, wherein the master comprises a reflection element which specularly reflects directed light according to geometric optics.

[0011] Document US 2010 / 003606 A1 discloses a method for processing a hologram. According to the method, a holographic image is formed in a photopolymer layer supported on a substrate. A color-matching film is applied to the opposing photopolymer layer to form a laminate. The temperature of the laminate is raised, subsequently cooled, and then exposed to a source of electromagnetic radiation for curing.

[0012] From the document US 2012 / 302 659 A1 a photopolymer formulation containing matrix polymers, writing monomers and photoinitiators and their use for the production of holographic media is known.

[0013] Further methods and devices are known from DE 10 2012 216219 A1, US 5 528 390 A, EP 2,738,624 B1 and US 2007 / 091395 A1. Summary

[0014] The object of the invention is to provide a method and a device for producing a hologram for a security element and a method for producing a value or security document, with which a security element having a hologram can be reliably produced, in particular also in the context of mass production.

[0015] To solve this problem, a method and a device for producing a hologram for a security element are provided according to independent claims 1 and 12. Furthermore, a method for producing a valuable or security document is provided according to independent claim 11. Further embodiments are the subject of dependent subclaims.

[0016] According to one aspect, a method for producing a hologram for a security element is provided, which method comprises the following: providing a holographic recording material in a device having processing stations which are configured to carry out successive process steps of a process step chain when producing a hologram for a security element and to process the holographic recording material according to process parameters;Processing the holographic recording material in a process step which is configured to expose the holographic recording material, wherein the holographic recording material is processed in accordance with process parameters assigned to the process step, and the processing comprises inscribing a holographic arrangement with the hologram for the security element into the holographic recording material by exposing the holographic recording material, wherein the hologram is formed in the holographic recording material encompassing a useful hologram area, wherein the holographic arrangement is produced upon exposure of the holographic recording material with a test element;Determining an optical diffraction efficiency of the holographic arrangement by means of a measuring device in a further process step, which is arranged downstream of the process step in the process step chain in the device with the processing stations, wherein the optical diffraction efficiency for the test element is determined; Changing at least one process parameter if the measured optical diffraction efficiency differs from a predetermined optical diffraction efficiency, wherein the process parameter comprises a laser parameter for the operation of a laser for inscribing the holographic arrangement and / or a level of a tempering temperature and / or a duration of a tempering of the holographic recording material and the holographic arrangement inscribed therein;and applying the at least one changed process parameter during further processing of the holographic arrangement in another process step which is located downstream of the further process step in the process step chain in the device with the processing stations, and / or for producing a further hologram for a security element in the device with the processing stations, wherein the optical diffraction efficiency along the process step chain in the device with the processing stations is measured by means of a second measuring device comprised by the measuring device after the holographic recording material has been stabilized by means of further light application, at least in the region of the useful hologram area covered by the hologram for the security element;

[0017] According to a further aspect, a device for producing a hologram for a security element is provided, comprising: processing stations configured to execute successive process steps of a process step chain when producing a hologram for a security element and, in doing so, to process the holographic recording material according to process parameters; and a measuring device configured to determine an optical diffraction efficiency of a holographic structure. The device is configured for the following: providing a holographic recording material;to process the holographic recording material in a process step such that the holographic recording material is exposed, wherein the holographic recording material is processed according to the process parameters assigned to the process step and the processing comprises inscribing a holographic arrangement with the hologram for the security element into the holographic recording material by exposing the holographic recording material, wherein the hologram is formed in the holographic recording material covering a useful hologram area, wherein the device is designed to produce the holographic arrangement when exposing the holographic recording material (2) with a test element;to use the measuring device to determine the optical diffraction efficiency for the holographic arrangement in a further process step, which is downstream of the process step in the process step chain in the device with the processing stations, and to determine the optical diffraction efficiency for the test element; to change at least one process parameter if the measured optical diffraction efficiency differs from a predetermined optical diffraction efficiency, wherein the process parameter comprises a laser parameter for the operation of a laser for inscribing the holographic arrangement and / or a level of a tempering temperature and / or a duration of a tempering of the holographic recording material and the holographic arrangement inscribed therein;and to apply the at least one changed process parameter during further processing of the holographic arrangement in another process step which is located downstream of the further process step in the process step chain in the device with the processing stations, and / or during production of a further hologram for a security element by means of the processing stations, wherein the device is further configured to measure the optical diffraction efficiency along the process step chain in the device with the processing stations by means of a second measuring device (15b) comprised by the measuring device (15), after the holographic recording material (2) has been stabilized by means of further application of light, at least in the region of the useful hologram area captured by the hologram for the security element.

[0018] According to another aspect, a method for producing a valuable or security document is provided, wherein a document body of the valuable or security document is formed with a security element having a hologram, which is produced according to the method specified above.

[0019] During the production of the hologram for the security element, which can then be incorporated in particular into a valuable and / or security document, the formation or production of the hologram in the holographic recording material is to be monitored or controlled based on a determination of the optical diffraction efficiency for a produced holographic arrangement with the hologram. The diffraction efficiency thus determined serves as a measure of the diffraction efficiency of the hologram in order to monitor its conformity to the respective requirements.

[0020] If it is determined that the determined diffraction efficiency deviates from a predetermined optical diffraction efficiency, be it a value or a range for the diffraction efficiency, at least one of the process parameters applied in the successive process steps of the process step chain in the device with the processing stations for producing holographic arrangements with a hologram is changed depending on this. The at least one changed process parameter can then be applied in the further processing of the holographic recording material with the just produced holographic arrangement with the hologram. Alternatively or additionally, it can be provided to apply the changed process parameter in the device with the processing stations when producing a subsequent or further hologram for a security element, for example a hologram to be produced directly afterwards.

[0021] This allows process optimization based on the changed process parameters to be applied during further processing of the hologram produced in the holographic recording material, not only for this purpose but also alternatively or additionally during the production of a subsequent holographic arrangement with a further hologram, for example in conjunction with the production of a security element, wherein this production takes place after the production of a preceding security element with a hologram. Overall, the hologram for the security element can thus be produced in the holographic recording material with greater reliability in accordance with the respective specifications of the production process. While the holographic recording material with the holographic arrangement incorporated therein is being processed in the device with the processing stations, the diffraction efficiency is measured in order to then, if necessary, base further optimizations on this.to adjust one or more process parameters.

[0022] In particular, a process parameter comprises an adjustable value of a physical quantity on machines and systems for controlling a given process, in this case, for controlling the method for producing a hologram for a security element within the scope of the process steps. For example, the process parameters can be laser parameters for operating a laser for inscribing a holographic arrangement or structure. Alternatively or additionally, process parameters can relate to other devices in the process. For example, a process parameter can be a time period (e.g., exposure time), a light intensity, and / or a temperature.

[0023] The optical diffraction efficiency is a characteristic value of diffractive optical elements, particularly optical gratings. It is defined as the ratio of the light intensity diffracted by a diffractive optical element into a specific solid angle to the light intensity incident on the diffractive optical element. It can therefore be used as a measure of the quality or efficiency of holographic structures. The diffraction efficiency is measured as a percentage. It may be necessary to specify a limit value below which the value cannot be exceeded, for example, approximately 30%.

[0024] Determining the optical diffraction efficiency for the holographic arrangement comprising the hologram for the security element can be carried out immediately after inscribing the holographic arrangement in the holographic recording material or after performing one or more further process steps thereafter.

[0025] Using the device, holographic arrangements with a respective hologram can be created on the holographic recording material as part of a continuous manufacturing process. The holographic recording material can be provided as a continuous material from a roll and introduced into the manufacturing process.

[0026] The determination of the diffraction efficiency can be performed on the continuous material. Alternatively or additionally, the determination of the diffraction efficiency can be performed on a section separated from the continuous material with the inscribed or exposed holographic arrangement.

[0027] The optical diffraction efficiency can be determined in the region of the hologram's useful area covered by the hologram for the security element. In this embodiment, the diffraction efficiency is determined in the region of the hologram's useful area covered by the hologram in the holographic recording material itself, i.e., in the region of the hologram. The diffraction efficiency is determined for a partial area that lies within the hologram's useful area, over which the hologram extends in the holographic recording material.

[0028] The optical diffraction efficiency can be determined outside the area of ​​the hologram's useful area covered by the hologram for the security element. In this embodiment, the optical diffraction efficiency is measured outside the hologram's useful area, over which the hologram extends, in an area in which, during the introduction of the holographic arrangement, a holographic structure was introduced as part thereof, which enables the measurement of the optical diffraction efficiency. Thus, the optical diffraction efficiency is determined outside the hologram for the security element itself, which, due to its simultaneous introduction with the hologram for the security element itself, indicates a measure of the diffraction efficiency of the hologram for the security element.

[0029] The holographic arrangement is created by exposing the holographic recording material to a test element, and the optical diffraction efficiency is determined for the test element. In addition to the hologram for the security element, a (holographic) test element is created during the holographic arrangement's incorporation, which can then be evaluated to determine the diffraction efficiency. The process control derived from the determination of the diffraction efficiency is then based on the measurement of the test element and provides a measure of the hologram's diffraction efficiency. The test element and the hologram are both created as part of the holographic arrangement when it is written into the holographic recording material.The test element can be arranged between successive hologram useful areas if the holographic arrangements are formed on a holographic recording material provided as a continuous material.

[0030] The test element can be produced at least partially in the area of ​​the hologram usable area covered by the hologram for the security element. The test element can be located entirely or partially in the area of ​​the hologram usable area over which the hologram for the security element extends in the holographic recording material. In this way, the test element can be integrated into a partial section of the hologram, expediently without impairing the holographic structure of the hologram. Here, the test element can be formed by an element or section of the hologram that remains unchanged for multiple holograms, for example, a hologram element that is not person-specific, in contrast to hologram elements that are person-specific.

[0031] The test element can be produced at least partially outside the area of ​​the hologram useful area covered by the hologram for the security element. In this embodiment, the test element is arranged partially or entirely outside the hologram useful area, over which the hologram extends flatly in the holographic recording material. This makes it possible to process the area of ​​the test element and the hologram useful area independently of one another during the subsequent process steps after the holographic arrangement has been written in, for example, by applying different processing steps or the same processing steps in different ways. For example, the area of ​​the test element, on the one hand, and the hologram useful area, on the other, can be exposed and / or tempered differently.

[0032] The optical diffraction efficiency can be measured along the process step chain in the device with the processing stations using a first measuring device included in the measuring device after the holographic arrangement has been written into the holographic recording material. The determination of the optical diffraction efficiency can be carried out immediately after the holographic arrangement has been written, in particular before subsequent process or processing steps, for example, a material-processing exposure and / or a tempering of the holographic recording material with the written holographic arrangement or structure.

[0033] According to the claimed invention, however, the optical diffraction efficiency along the process step chain in the device with the processing stations is measured at least by means of a second measuring device included in the measuring device, after the holographic recording material has been stabilized by means of further light application, at least in the region of the useful hologram area covered by the hologram for the security element. The optical diffraction efficiency can be determined immediately after the further light application or after one or more subsequent process steps. The further light application can comprise irradiation with UV light. By means of the further light application, chemical processes or reactions can be initiated in the holographic recording material that serve to stabilize the material without (fully) curing it.Such process steps are known as such in various embodiments.

[0034] The optical diffraction efficiency can be additionally measured along the process chain in the device with the processing stations using a third measuring device included in the measuring device, after the holographic recording material has been cured at least in the region of the hologram's useful area covered by the hologram for the security element. Curing can include the application of thermal energy (tempering). If a test element is provided outside the hologram's useful area, this area of ​​the holographic recording material can be processed in the same or different manner as the processing of the hologram's useful area.

[0035] The optical diffraction efficiency can be measured in a region of the holographic recording material outside the hologram's effective area, which region is covered by the test element, at the time of measuring the diffraction efficiency. The region covered by the test element is free from further processing by means of further light application for stabilization and / or curing. In this example, the hologram's effective area is further processed after the holographic arrangement or structure has been inscribed, in particular by means of further light application and / or tempering. The test element formed separately from the hologram's effective area is not subjected to these process steps, so that the result of the determination of the diffraction efficiency for the test element is not influenced by the effects of these process steps.The diffraction efficiency can thus be measured for the test element in a state after inscription, even though the hologram's useful area has already been further processed. It can be provided that the holographic recording material in the area of ​​the test element, which was created during inscription of the holographic arrangement or structure, remains essentially in the material state at the time of inscription.

[0036] Before processing the holographic recording material for inscribing the holographic arrangement, the holographic recording material can be determined with regard to at least one material property using a further measuring device, and a process parameter can be adjusted during processing the holographic recording material for inscribing the holographic arrangement depending on the at least one material property. The process parameter can, for example, relate to exposure time and / or light intensity during inscribing the holographic arrangement. In addition to process control based on determining the diffraction efficiency, it is provided here to determine the holographic recording material before inscribing the holographic arrangement or structure in order to adjust one or more process parameters depending thereon, in particular during inscribing the holographic arrangement.In addition, further process parameters for subsequent process steps can be set or controlled depending on the specific material property(s) for the holographic recording material, for example, the duration of subsequent tempering and / or the level of a tempering temperature. Using the additional measuring device, for example, optical properties of the holographic recording material can be determined before the holographic arrangement is written, such as transmittance and / or reflectivity.

[0037] The successive process steps of the process chain can be carried out in the device with the processing stations in several process chambers. The process chambers can each comprise one or more substantially light-tight process chambers, for example, a light-tight process chamber for inscribing the holographic arrangement or structure into the holographic recording material.

[0038] When inscribing the holographic arrangement or structure, it may be intended to use a holographic master. In this case, when inscribing the holographic structure with the hologram, light passes through the holographic recording material and is then diffracted and / or reflected on the back side by the holographic master, thus incorporating the hologram into the holographic recording material.

[0039] Holographic recording materials are known in various forms. For example, they can be hologram films. The holographic recording material can be single-layer or multi-layer.

[0040] The changed process parameter, which is changed in response to determining the diffraction efficiency and detecting a deviation, may, for example, concern exposure time and / or light intensity when writing the holographic arrangement, in particular the exposure time may be minimized.

[0041] The embodiments explained above can be provided accordingly in connection with the device for producing a hologram for a security element.

[0042] A security element is a structural unit that comprises at least one security feature. A security element can be a stand-alone structural unit that can be connected, for example, glued, to a security document, which may also be a valuable document. However, it can also be an integral component of a security document. An example of the former is a visa that can be glued onto a security document. An example of the latter is a hologram integrated into a banknote or ID card, for example, a laminated hologram.

[0043] A security feature is a structure that can only be produced or reproduced without authorization with increased effort (compared to simple copying) or not at all.

[0044] Examples of security and / or valuable documents include: identity cards, passports, ID cards, access control badges, visas, tax stamps, tickets, driver's licenses, vehicle registration documents, banknotes, checks, postage stamps, credit cards, any chip cards, and adhesive labels (e.g., for product security). Such security and / or valuable documents typically comprise a substrate, a print layer, and optionally a transparent cover layer. A substrate is a carrier structure to which the print layer containing information, images, patterns, and the like is applied. All commonly used paper and / or plastic-based materials are suitable for a substrate.

[0045] A code or pattern is individualizing if it is unique for a person or object, or for a group of people or objects from a larger total of people or objects. A code that is individualizing for a group of people within the total population of a country is, for example, the city of residence. A code that is individualizing for a person is, for example, the number of an identity card or a passport photo. A code that is individualizing for a group of banknotes within the total volume of banknotes is the denomination. The serial number is individualizing for a banknote. Examples of non-individualizing codes or patterns are coats of arms, seals, national emblems, etc.

[0046] A holographic recording material is a layer of photosensitive material in which holograms can be recorded through irreversible, but also reversible, photochemical and / or photophysical processes by exposure. Photopolymers, which are often used in holography, are just a few examples. Description of implementation examples

[0047] Further embodiments are explained below with reference to the figures of a drawing. Herein: Fig. 1 is a schematic perspective view of an apparatus for producing a hologram for a security element in a holographic recording material, and Fig. 2 is a schematic view of a method for producing a hologram for a security element.

[0048] The invention provides for continuous control of the diffraction efficiency during ongoing production and automated control of the process or laser parameters in order to increase process stability and reduce scrap.

[0049] In Fig. 1 shows a schematic perspective view of a device for producing a hologram 1 for a security element in a holographic recording material 2, which in the example shown is provided as a continuous material from a roll 3.

[0050] The roll 3 with the light-sensitive holographic recording material 2 is arranged in a light-tight chamber 4. The holographic recording material 2 is fed to a processing chamber 7 via a deflection roller 5 and a transport system 6. In the processing chamber 7, the holographic recording material 2, which can be a film material, is positioned above a master 8. To inscribe a holographic arrangement or structure with a hologram for a security element, the holographic recording material 2 is exposed to a laser beam 9, which passes through the holographic recording material 2 and is diffracted and / or reflected by the master 8.

[0051] The laser beam 9 is adjusted and guided within an optical chamber 10. In a subsequent chamber 11, the holographic structures of the holographic recording material 2 introduced by the exposure are stabilized by UV irradiation with the aid of an exposure device 12.

[0052] Subsequently, the holographic recording material 2 is cured by supplying heat with the aid of a tempering device 13, wherein the continuous material is guided over further deflection rollers 14.

[0053] A process control method provides for determining the diffraction efficiency using a measuring device 15 after exposure of the holographic recording material 2 to form the holographic arrangement or structure, in order to test the quality and accuracy of the inscribed hologram. In the example shown, the measuring device 15 has a first, a second, and a third measuring device 15a, 15b, 15c. Suitable sensors in the measuring devices 15a, 15b, 15c include, for example, spectrometers that measure the diffraction efficiency of the exposed holographic structure at a suitable angle and under suitable, optionally monochromatic, illumination.

[0054] A measurement by means of the third measuring device 15c is carried out on the UV-stabilized and cured holographic recording material 2, whereby there is no impairment of the holographic recording material 2.

[0055] A measurement of the diffraction efficiency using the second measuring device 15b is performed on the UV-stabilized but uncured holographic recording material 2. Impairment of the introduced holographic structure can be avoided by appropriately selecting the sensor illumination (illumination wavelength and / or intensity). The second measuring device 15b operates, for example, with a separately exposed test or inspection field of the holographic arrangement, which lies outside the exposed hologram area of ​​the hologram, since the structures of the holographic recording material 2 are not yet thermally cured here, and thus, impairment of the structures of the test field is likely.

[0056] The optical diffraction efficiency can be measured along the process step chain in the device 1 with the processing stations by means of the first measuring device 15a comprised by the measuring device 15 after the holographic arrangement has been written into the holographic recording material 2. The optical diffraction efficiency is determined immediately after the holographic arrangement has been written, in particular before subsequent process or processing steps, for example, the material-processing exposure and the tempering of the holographic recording material 2 with the written holographic arrangement or structure.

[0057] The first measuring device 15a can be used with the optionally separately exposed test or inspection field of the holographic arrangement, which lies outside the exposed hologram usable area of ​​the hologram, since here the structures of the holographic recording material 2 are neither UV-stabilized nor cured and thus an impairment of the structures of the test field is likely.

[0058] The determination of the diffraction efficiency is carried out on the holographic recording material 2 in the region of the hologram's effective area, i.e., the area covered by the hologram in the holographic recording material 2, and / or on the test or inspection field outside the hologram's effective area, using one or more of the measuring devices 15a, 15b, 15c for this purpose. The test or inspection field is a holographic element optionally introduced in addition to the hologram itself, on which the diffraction efficiency can be measured as a measure of the hologram's quality and accuracy. It can be exposed together with the hologram, in particular simultaneously.

[0059] The test element can be produced at least partially in the area of ​​the hologram's useful area covered by the hologram for the security element, for example, it can be formed by a section or element of the hologram itself. The test element can be located entirely or partially in the area of ​​the hologram's useful area, over which the hologram for the security element extends in the holographic recording material 2. In this way, the test element can be integrated into a partial section of the hologram, expediently without impairing the holographic structure of the hologram. In this case, the test element can be formed by an element or section of the hologram that remains unchanged for multiple holograms, for example, a hologram element that is not person-specific, in contrast to hologram elements that are designed specifically for a person (personalized security element).

[0060] A further measuring device 16 enables the properties of the holographic recording material 2 to be measured before exposure. Measuring the properties of the holographic recording material 2 at this point advantageously enables the adjustment of the process or laser parameters before exposure and optimizes the process quality and / or further minimizes the process time. At this position, the holographic recording material 2 is neither UV-stabilized nor cured. Thus, the properties of the holographic recording material 2 should be measured outside the then exposed hologram area and / or preferably in the NIR wavelength range.

[0061] It has been found that a stable and high diffraction efficiency of the hologram depends on various factors. These factors include the process temperature during exposure and the material properties of the recording material to be exposed, which can vary considerably from batch to batch. In order to ensure improved process stability with lower waste, the following can be provided: When exposing the holographic recording material 2 with the laser, a test field is also exposed if no suitable field is available in the layout of the hologram's usable area. During the further processing, the diffraction efficiency is measured continuously at at least one point during production, i.e. on each workpiece (manufactured part). Based on the measured values ​​obtained, one or more process parameters are automatically optimized and adjusted during ongoing production.This allows for better adjustment of production parameters and significantly reduces waste. Such adjustment of process parameters occurs when the measured diffraction efficiency deviates from a specified value / range. For example, the exposure time and / or intensity for exposing the holographic recording material 2 during inscription of the holographic array can then be changed.

[0062] Fig. 2 shows a schematic representation of a method for producing a hologram for a security element in the holographic recording material 2 using the device from Fig. 1In step 50, the holographic recording material 2 is provided, for example as continuous material from a roll, in order to then be exposed in step 52 to inscribe the holographic arrangement or structure. The master 8 is used here. After the holographic structure has been inscribed into the holographic recording material 2, the material is subjected to further process steps in the device 1. In this case, the optical diffraction efficiency for the inscribed holographic arrangement is determined (step 53) by means of one or more of the measuring devices 15a, 15b, 15c, but according to the claimed invention at least by means of the measuring device 15b, in order to then check in step 54 whether the measured optical diffraction efficiency corresponds to or deviates from a predetermined optical diffraction efficiency.The test can be carried out by means of data processing in a suitable evaluation device, which is connected at least to the measuring device 15. Depending on the test result, control signals for generating and applying the laser beam 9 can be generated.

[0063] If the measured optical diffraction efficiency deviates, at least one process parameter according to which the holographic recording material 2 is processed in the device 1 is adjusted in step 55. The process parameter adjustment can then be applied to the further processing of the holographic arrangement for which the diffraction efficiency was determined.

[0064] In addition, the process parameters are adjusted for producing subsequent holograms in the holographic recording material 2 based on the measured properties of the holographic recording material 2 before exposure, which is made possible by the measuring device 16. List of reference symbols

[0065] 1Device 2Holographic recording material 3Roll 4Light-tight chamber 5Deflection roller 6Transport system 7Process chamber 8Master 9Laser beam 10Optical chamber 11Subsequent chamber 12Exposure device 13Temperature control device 14Further deflection rollers 15Measuring device 15aFirst measuring device 15bSecond measuring device 15cThird measuring device 16Further measuring device 50, ..., 55Process steps

Claims

1. A method for producing a hologram for a security element, comprising: - providing a holographic recording material (2) in an apparatus (1) having processing stations that are configured to carry out successive process steps of a process step chain during the production of a hologram for a security element and thereby process the holographic recording material (2) according to process parameters; - processing the holographic recording material (2) in a process step that is configured to expose the holographic recording material (2), wherein - the holographic recording material (2) is thereby processed in accordance with process parameters assigned to the process step and - the processing comprises writing a holographic arrangement including the hologram for the security element into the holographic recording material (2) by means of exposing the holographic recording material (2), wherein the hologram is formed in the holographic recording material (2) to cover a hologram functional area, wherein the holographic arrangement is produced with a test element during exposure of the recording material (2); - determining an optical diffraction efficiency of the holographic arrangement by means of a measuring apparatus (15) in a further process step, which in the process step chain in the apparatus (1) with the processing stations lies after the process step, wherein the optical diffraction efficiency is determined for the test element; - modifying at least one process parameter if the measured optical diffraction efficiency deviates from a predetermined optical diffraction efficiency, wherein the process parameter comprises a laser parameter for operating a laser for writing the holographic arrangement and / or a tempering temperature level and / or duration of a tempering process for the holographic recording material (2) and the holographic arrangement written therein; and - applying the at least one modified process parameter during further processing of the holographic arrangement in another process step, which in the process step chain in the apparatus (1) with the processing stations lies after the further process step, and / or during production of a further hologram for a security element in the apparatus (1) with the processing stations, characterized in that the optical diffraction efficiency is measured along the process step chain in the apparatus with the processing stations by means of a second measuring device (15b) included in the measuring apparatus (15), after the holographic recording material (2) has been stabilized by means of further light application at least in the region of the hologram functional area covered by the hologram for the security element.

2. The method according to claim 1, characterized in that the optical diffraction efficiency is determined in the region of the hologram functional area covered by the hologram for the security element.

3. The method according to claim 1 or 2, characterized in that the optical diffraction efficiency is determined outside the region of the hologram functional area covered by the hologram for the security element.

4. The method according to any one of the preceding claims, characterized in that the test element is produced at least partially in the region of the hologram functional area covered by the hologram for the security element.

5. The method according to any one of the preceding claims, characterized in that the test element is produced at least partially outside the region of the hologram functional area covered by the hologram for the security element.

6. The method according to any one of the preceding claims, characterized in that the optical diffraction efficiency is additionally measured along the process step chain in the apparatus (1) with the processing stations by means of a first measuring device (15a) included in the measuring apparatus (15), after the holographic arrangement has been written into the holographic recording material (2).

7. The method according to any one of the preceding claims, characterized in that the optical diffraction efficiency is additionally measured along the process step chain in the apparatus with the processing stations by means of a third measuring device (15c) included in the measuring apparatus (15), after the holographic recording material (2) has been cured at least in the region of the hologram functional area covered by the hologram for the security element.

8. The method according to any one of the preceding claims, insofar as it refers back to claim 5, characterized in that the optical diffraction efficiency is measured in a region of the holographic recording material (2) covered by the test element outside the hologram functional area, wherein the region covered by the test element is free from processing by means of the further light application for stabilizing and / or curing.

9. The method according to any one of the preceding claims, characterized in that before processing the holographic recording material (2) to write the holographic arrangement, the holographic recording material (2) is evaluated by means of a further measuring device (16) with respect to at least one material property and a process parameter during processing the holographic recording material (2) to write the holographic arrangement is set depending on the at least one material property.

10. The method according to any one of the preceding claims, characterized in that the successive process steps of the process step chain in the apparatus (1) with the processing stations are performed in multiple process chambers.

11. Method for producing a value or security document, wherein a document body is formed with a security element comprising a hologram, said security element being produced using a method according to at least one of the preceding claims.

12. Apparatus (1) for producing a hologram for a security element, comprising: - processing stations that are configured to carry out successive process steps of a process step chain during the production of a hologram for a security element and thereby process the holographic recording material (2) according to process parameters; and - a measuring apparatus (15) that is configured to determine an optical diffraction efficiency of a holographic structure; wherein the apparatus is configured - to provide a holographic recording material (2); - to process the holographic recording material (2) in a process step, in such a manner that the holographic recording material (2) is exposed, wherein - the holographic recording material (2) is thereby processed according to process parameters assigned to the process step and - the processing comprises writing a holographic arrangement including the hologram for the security element into the holographic recording material (2) by means of exposing the holographic recording material (2), wherein the hologram is formed in the holographic recording material (2) to cover a hologram functional area, wherein the apparatus is configured to produce the holographic arrangement with a test element during exposure of the holographic recording material (2); - to determine the optical diffraction efficiency of the holographic arrangement by means of the measuring apparatus (15) in a further process step, which in the process step chain in the apparatus with the process stations lies after the process step, and to determine the optical diffraction efficiency for the test element; - to modify at least one process parameter if the measured optical diffraction efficiency deviates from a predefined optical diffraction efficiency, wherein the process parameter comprises a laser parameter for operating a laser for writing the holographic arrangement and / or a tempering temperature level and / or duration of a tempering process for the holographic recording material (2) and the holographic arrangement written therein; and - to apply the at least one modified process parameter during further processing of the holographic arrangement in another process step, which in the process step chain in the apparatus (1) with the processing stations lies after the further process step, and / or during production of a further hologram for a security element by means of the processing stations, characterized in that the apparatus is further configured to measure the optical diffraction efficiency along the process step chain in the apparatus with the processing stations by means of a second measuring device (15b) included in the measuring apparatus (15), after the holographic recording material (2) has been stabilized by means of further light application at least in the region of the hologram functional area covered by the hologram for the security element.