Device comprising holographic marking, master plate for producing such a device, and corresponding methods

Abstract

The invention relates to devices comprising a holographic material and a holographic marking (13) provided in the holographic material. The holographic marking (13) here is only sensitive to light at a predefined wavelength and / or to light from a predefined direction, and / or is configured to diffract light only in a further predefined direction. The device can further contain a main hologram (12). The invention additionally relates to corresponding master plates for producing such devices, methods and production devices.

Description

[0001] Description

[0002] Device with holographic marking, master plate for producing such a device, and corresponding methods

[0003] The present application relates to devices with a holographic marking, master plates for producing such devices and corresponding methods.

[0004] Different types of markings are used for different products, i.e., devices. These can be markings required during the product's manufacture, such as alignment marks. These are used for alignment and positioning during the device's production process. Other examples are markings for traceability, such as article numbers, batch / lot numbers, serial numbers, or UDI (unique device identifier) ​​codes.

[0005] Other examples include brand logos, quality seals, or other coded content such as process parameters or price / product information.

[0006] In some applications, such as brand logos or quality seals, it is desirable for the markings to be visible; in other cases, markings that are not readily visible (in particular, markings that are not normally visible to an end user) may be desirable.

[0007] Conventional markings are printed, embossed, punched, laser-etched, or applied using an adhesive label. Thermal processes are also possible.

[0008] Holographic markings are also used for some purposes. Examples can be found in DE 102007 061 626 A1, DE 4 124 203 A1, DE 102014 117 511 A1, DE 102017211 914 A1, EP 3 955 051 A1, US 2020 / 0 301 157 A1, or DE-OS 1 963 787.

[0009] It is an object to provide improved possibilities in this regard. A device according to claim 1, 2, 3, 14, or 20, a vehicle according to claim 21, a master plate according to claim 23, a method according to claim 29 or 32, or a manufacturing device according to claim 31 are provided. The subclaims define further embodiments.

[0010] Generally, according to various aspects, a device comprises a holographic material and at least one holographic marking provided in the holographic material. In a first aspect, the holographic material also has a main hologram. A main hologram is a hologram that fulfills a function of the device; this can be any function that can be fulfilled by holograms, for example, display functions in the form of a holographic ground glass screen, lighting functions, for example in motor vehicles, a function of a projection surface in the form of a holographic diffuser, and the like.

[0011] The holographic marking is

[0012] - only sensitive to light of a given wavelength and / or

[0013] - only sensitive to light from a given direction, and / or

[0014] - designed to bend light only in one further specified direction.

[0015] The main hologram, however, is:

[0016] - sensitive to light outside the specified wavelength (although it may also be additionally sensitive to light of the specified wavelength), and / or

[0017] - sensitive to light coming from a direction other than the specified direction (here too, it can also be sensitive to light coming from the specified direction), and / or

[0018] - designed to bend light in a direction other than the further specified direction (and it can also bend light in the specified direction).

[0019] "Sensitive" means that the respective hologram (holographic marking or main hologram) only diffracts the light when irradiated with light of the respective property (wavelength and / or direction) in accordance with the respective hologram's function, for example, to create an image. Otherwise, the light is diffracted or not diffracted in a way that renders the function ineffective. Thus, the marking is only visible under certain conditions (when illuminated with light of the specified wavelength, from the specified direction, and / or when viewed from the further specified direction), and invisible under other lighting, while the main hologram is also visible under other conditions. Thus, the marking can be invisible, for example, during normal use of the device.The predetermined wavelength can be a wavelength range around a central wavelength, and the predetermined direction and / or the further predetermined direction can be, for example, a club-shaped directional range.

[0020] If the holographic marking is only used during a manufacturing process of the device, the holographic material can be incorporated into the finished device in such a way that, for example, it cannot be illuminated from the specified direction or cannot be viewed from the further specified direction, so that the holographic marking is structurally prevented from being visible in the finished device. This can be achieved by appropriate shading of the holographic marking in the device. Such shading prevents light from reaching the hologram from the specified direction and / or prevents the hologram from being viewed from the specified direction by blocking the respective light path (illumination or viewing).For this purpose, the holographic material can be provided in a recess, and side walls of the recess can then provide appropriate shading.

[0021] Alternatively, the at least one holographic marking can also be arranged in the device in such a way that, during a given normal use of the device, it cannot be illuminated with light from the given direction and / or cannot be viewed from the further given direction. Such an arrangement can be used, for example, if the holographic marking is not required by a user of the device or of a system in which the device is installed, for example a vehicle, but is required, for example, for maintenance of the device or the system. In such a case, shading can be provided as described above. To read the marking, a separate mobile lighting device can then be arranged next to the holographic marking in order to illuminate the holographic marking from the appropriate direction.

[0022] In the case of a vehicle (e.g., automobile, truck, bus, train, or aircraft), the holographic material may be disposed on or in a window of a vehicle. A corresponding vehicle is also provided. In such a case, the normal use of the device may be the use of the vehicle by a driver.

[0023] The device can then further comprise an illumination device for the main hologram arranged in a dashboard of the vehicle. The dashboard can also serve to shade the holographic marking so that the holographic marking is not visible to vehicle occupants. In some embodiments, the vehicle then generally does not have an illumination device for the holographic marking. However, in some embodiments, a separate mobile illumination device can be arranged, for example, by a service technician, so that the holographic marking becomes visible.

[0024] Accordingly, a method is also provided that includes arranging a mobile illumination device to illuminate and ultimately read the holographic marking. Positioning during the arrangement may be determined by a geometry of the vehicle (or other system in which the device is arranged) and the illumination device.

[0025] The window can be a windshield or a side window.

[0026] The holographic marking can mark a specified area of ​​the windscreen, for example as a stone chip marking.

[0027] The above application of a holographic marking in a vehicle window that is not readable or not readable during normal operation can also be implemented without the main hologram, so that no main hologram is imprinted in the holographic material. Optionally, in the above first aspect, but also in a second aspect, the holographic marking is provided as a volume hologram, wherein the holographic marking is only sensitive to a predetermined wavelength, and / or is only sensitive to light from a predetermined direction, and / or only diffracts light in another predetermined direction. With a volume hologram, such properties can be easily realized as intrinsic properties of the volume hologram.A volume hologram is a hologram in which a holographic layer is also used in the thickness direction perpendicular to a surface to store holographic information and not just a two-dimensional interference structure, for example, on a surface.

[0028] The holographic marking can be used for various purposes. The holographic marking can include one or more marking elements from a group consisting of:

[0029] - an alignment mark, i.e. a mark that can be used to align different components or devices with each other,

[0030] - a numbering, for example a consecutive product numbering,

[0031] - a QR code in which any information can be encoded,

[0032] - a UDI code, i.e. a unique alphanumeric or numeric code for a medical device,

[0033] - a safety marking, such as a warning notice,

[0034] - a brand

[0035] - a logo

[0036] - a test mark, such as a CE test mark,

[0037] - a process parameter, i.e. information about a parameter used during the manufacture of a product, and

[0038] - a price label that indicates a price of a product.

[0039] The holographic marking can take up less than 20% of the surface area of ​​the holographic material. This leaves space, for example, for the above-mentioned main hologram. The surface area of ​​the main hologram can be at least twice as large, for example at least 4x as large or at least 10x as large as the surface area of ​​the at least one marking. In addition, a master plate is provided for producing a device, in particular a device as described above. The master plate comprises a first region for writing a holographic marking into a holographic material. A master plate is a device used to produce holograms by exposing a hologram using the master plate, wherein the structure of the hologram is determined using the master plate. This process is also referred to as replication.For this, a light beam, typically a laser beam, is split into an object beam and a reference beam. The object beam is diffracted by the master plate and then interfered with the reference beam in a photosensitive material, thereby imprinting the hologram into the photosensitive material.

[0040] The first region can comprise a holographic diffuser. A holographic diffuser is an element which, when illuminated with a pattern corresponding to the marking, diffracts a corresponding pattern onto a holographic material, thus exposing the holographic material. Such a diffuser can have a scattering angle range between 5° and 10°, but is not limited to this. Such a scattering angle range enables the marking to be recognized from a certain directional range, while simultaneously keeping the blurring of the marking within acceptable limits if there is a distance of, for example, 1 mm between the diffuser and the holographic material during exposure. The diffuser can be a transmission diffuser, for example, with a diffraction efficiency of approximately 50%, or a reflection diffuser, for example, with a diffraction efficiency greater than 90%. Thus, variable markings can be used, for example,Serial numbers. Alternatively, the holographic diffuser itself has a shape corresponding to a mark to be written. This then creates a mark with a fixed shape, for example for alignment marks that should be the same for each device. The holographic diffuser can then have a shape of the mark in a first part of the first area. This first part can then be illuminated across the surface, and the corresponding mark is written. In a second part of the first area, the holographic diffuser can be flat. Here, the diffuser can then be illuminated with a variable pattern, for example with a projector as explained below, in order to write variable marks.The first part and the second part can each make up the entire diffuser, or they can be combined so that the first part writes a fixed mark and the second part can write another mark (such as a serial number and the like).

[0041] The holographic diffuser can be a reflective diffuser or a transmissive diffuser. With a reflective diffuser, the holographic material is illuminated after being reflected off the diffuser; with a transmissive diffuser, the holographic material is illuminated in transmission through the diffuser. In other words, for exposure, with a reflective diffuser, the holographic material is placed between a light source and the master plate, while with a transmissive diffuser, the master plate is placed between the light source and the holographic material.

[0042] The master plate can further include a second hologram region for writing the aforementioned main hologram into the holographic material. The first hologram region and the second hologram region can be applied separately to the master plate, for example, on a glass pane. Alignment marks can be used for this purpose, which enable alignment of the first hologram region and the second hologram region with each other on the master plate.

[0043] Using such a master plate, a device as described above can be produced by arranging the holographic material adjacent to the master plate and then exposing the master plate to write the marking into the holographic material. With a planar holographic diffuser as described above for the wider range, exposure can occur through a mask element, wherein the mask element determines the shape and / or displayed content of the marking. The mask element can be any type of element that shapes exposure light accordingly, for example, an LCD display, a digital micromirror device (DMD), or even a fixed mask for a specific type of device.

[0044] A manufacturing device then comprises a holder for such a master plate and an exposure module for writing a holographic marking into a holographic material by means of the first hologram area of ​​the master plate.

[0045] Various embodiments are explained in more detail below with reference to the accompanying drawings. Fig. 1 shows a schematic representation of a device according to an embodiment,

[0046] Figures 2A, 2B, 3A, 3B, 4A, 4B, 5A, 5B, 6A, 6B, various properties of holographic markings of various embodiments,

[0047] Figures 7A and 7B illustrate shading in some embodiments, and Figures 7C to 7I show application examples of such shading.

[0048] Figures 8, 9 and 10 show master plates according to various embodiments,

[0049] Fig. 11 shows a manufacturing device according to an embodiment,

[0050] Fig. 12 shows an exposure process with a master plate in transmission,

[0051] Fig. 13 shows a device produced with the exposure of Fig. 12,

[0052] Fig. 14 shows an exposure process with a master plate in reflection,

[0053] Fig. 15 shows a device produced by the exposure process of Fig. 14,

[0054] Figures 16-21 are illustrations to explain the production of a master plate,

[0055] Fig. 22 shows a manufacturing device according to an embodiment,

[0056] Fig. 23 a layer stack in the manufacturing device of Fig. 22, and

[0057] Fig. 24 is a diagram for the production of the mode of operation of a holographic diffuser in various embodiments.

[0058] Various embodiments are explained in detail below. These are not to be interpreted as limiting. Variations and modifications described for one of the embodiments are also applicable to other embodiments and will not be explained repeatedly. The same reference numerals in the figures denote identical or corresponding elements, which are also not explained in detail.

[0059] The device of Fig. 1 comprises a carrier 11 with holographic material into which at least one holographic marking 13 has been exposed. Furthermore, a main hologram 12 has been exposed into the holographic material to fulfill a holographic function of the device, as already explained above. The carrier 11 can contain a photopolymer on a film made of a carrier polymer, with the main hologram 12 and the holographic marking 13 then exposed into the photopolymer. While a single holographic marking 13 is shown in Fig. 1, multiple holographic markings can be provided, even for different purposes (e.g., alignment marks, product codes, logos, trademarks, etc., as explained above).

[0060] The holographic marking 13 can be embossed into the holographic material as a volume hologram. The holographic marking 13 can be angle-sensitive and / or wavelength-sensitive, meaning it is only visible with light of a specific wavelength and / or a specific illumination direction, and / or can only be viewed at a specific angle because it scatters light only in a specific direction. Such angles and wavelengths are determined when the holographic marking 13 is embossed into the holographic material by using light of a specific wavelength for exposure, and by irradiating the object and reference waves at appropriate angles.It should be noted that “light” in this sense is not limited to the visible range and, for example, markings can also be illuminated using infrared light or ultraviolet light, which can then only be viewed with infrared light or ultraviolet light.

[0061] The main hologram 12, however, can also or alternatively be designed for other wavelengths and angles.

[0062] This will now be explained in more detail with reference to Figures 2-6, each comprising a sub-figure A and a sub-figure B. Figures 2-6 show, as an example, three holographic markings 13A-13C in the form of crosses, for example as alignment markings, together with a main hologram 12 on a carrier 11.

[0063] Figures 2A and 2B illustrate that the holographic markings 13A-13C are only visible under specific illumination at a specific angle and wavelength. This illumination is symbolized by obliquely incident illumination light 20 in Fig. 2A. A camera 14 represents an observer. Reference numeral 15 denotes the image perceived by the camera. In Fig. 2A, both the markings 13A-13C and a pattern generated by the main hologram 12 are visible in image 15. In Fig. 2B, the specific illumination 20 is missing, and only illumination by ambient light, for example, is present. In this case, only the pattern generated by the main hologram 12 is visible in image 15.In this example, the main hologram 12 may be a daylight hologram, or a hologram illuminated with additional illumination (not shown) that is different from the illumination light 20.

[0064] Figures 3A and 3B illustrate wavelength selectivity. Figure 3A corresponds to Figure 2A, meaning that here the device, in particular the markings 13A-13C, is illuminated with the appropriate illumination light 20, and the markings 13A-13C are visible in image 15. In Figure 3B, the device, in particular the markings 13A-13C, is illuminated with illumination light 30 at the same angle as the illumination light 20, but with a different wavelength. In this case, the markings 13A-13C are not visible in image 15.

[0065] Figures 4A and 4B illustrate the angular selectivity during illumination. Figure 4A corresponds to Figures 2A and 3A, i.e., the illumination is performed with illumination light 20 at the correct angle and wavelength, and the markings 13A-13C are visible in image 15. In Figure 4B, the illumination is performed with illumination light 40 at the same wavelength as illumination light 20 (i.e., the correct wavelength), but at a different angle. Here, the markings are not visible in image 15.

[0066] Figures 5A and 5B illustrate the selectivity with respect to the observation direction, i.e., the direction in which light is diffracted by the markings 13A-13C, thus making the markings visible. Figure 5A corresponds to Figures 2A, 3A, and 4A, where illumination is provided by the illumination light 20 and the camera 14 is arranged as in the previous figures. In Figure 5B, the camera 14 is now arranged at a different angle to the device. Here, the markings in the image 15 are not visible, while the light pattern generated by the main hologram 12 is still visible. Tolerance with respect to the observation direction can be influenced by the properties of a diffuser used during exposure, as described below. Using a diffuser with a larger scattering range (angular range) results in lower selectivity with respect to the observation direction.For example, a permissible tolerance range can be reduced when positioning a camera that reads the marking.

[0067] Finally, Figures 6A and 6B illustrate the dependence on the type of light source. Figure 6A corresponds to Figures 2A, 3A, 4A, and 5A, meaning that the markings in image 15 are visible due to the appropriate illumination light 20. The illumination light 20 can, for example, be collimated light generated by a corresponding optics. In Figure 6B, the illumination is provided by a lamp 60 that generates non-collimated light. Here, the markings are not visible.

[0068] In the above examples, the light pattern generated by the main hologram 12 is always visible in the respective sub-figures "B." In other embodiments, special illumination must also be used for the main hologram, which differs from the illumination for the markings, in order for the corresponding light pattern to become visible.

[0069] Some markings are only required during the manufacturing process of the device, but not during later use. For example, alignment markings can be used to determine an installation location so that the main hologram 12 is in the correct position within a device. After the corresponding installation, the alignment markings are then no longer required. In such cases, installation can be carried out in such a way that the markings are no longer visible in the installed state because correct illumination and / or observation can no longer take place due to shadowing. This is illustrated in Figures 7A and 7B. Figure 7A shows a device with a carrier 11 and a holographic marking 13, which is to be illuminated by illuminating light 20 at the angle shown so that it can be seen by an observer 14, here symbolized by an eye.7B shows an installed state in which the carrier 11 is arranged in a recess surrounded by walls 70. The walls 70 provide shading so that the illumination light 20 can no longer strike the marking 13 at the required angle, thus preventing the observer 14 from perceiving the marking.

[0070] In some cases, the marking 13 may not be required during normal operation of the device and should not be visible, but should nevertheless be readable. This may be the case, for example, with markings in the vehicle sector that are not required by a driver or vehicle occupant during normal operation, but are required, for example, by a service technician. Such markings may indicate, for example, type designations, serial numbers, glass types, or the like. Examples of such applications in the vehicle sector are explained with reference to Figures 70 to 7I.

[0071] Fig. 7C shows a top view of a portion of a vehicle windshield 71, approximately from the driver's perspective. The holographic material with main hologram 12 and holographic marking 13 is arranged on or in the windshield 71, for example, laminated between two panes of glass. Fig. 7D shows a side view.

[0072] The main hologram 12 serves here as a holographic focusing screen and can be illuminated with an illumination light beam 73 by an illumination device 712, which can be arranged in a dashboard 74, with data to be reflected for viewing by a driver of the vehicle. On the other hand, the dashboard 74 shades the holographic marking 13 so that the marking is not illuminated by an illumination light beam 72, which would be necessary for the driver to see the holographic marking. Thus, during normal use of the vehicle, in particular while driving, the holographic marking is not visible. The vehicle also does not contain an illumination device for the holographic marking.

[0073] As can be seen in Fig. 7D, the holographic marking can be illuminated from outside the vehicle, for example by a service technician, with an illuminating light beam 79 so that it can be read. Figures 7E and 7F show further side views, wherein in Fig. 7F the windshield 71 has a steeper angle (as is the case, for example, with a bus or truck) than in Fig. 7E. Here, the holographic marking 13 can be read using a mobile illumination unit 75, which can be arranged outside the vehicle as shown in the case of the holographic marking, or inside the vehicle. The illumination unit 75 has a light source for generating the illuminating light beam 79 at a suitable angle. Furthermore, the illumination unit 75 can have an image sensor 77 for recording the holographic marking.Additionally or alternatively, viewing by the human eye, for example, of a service technician, can also be performed. An example of an arrangement of the lighting unit inside the vehicle is shown in Fig. 7E as lighting unit 75'. Such a lighting unit 75' can be shaped such that it can be fitted into a position in the vehicle suitable for illuminating the holographic marking. For example, the lighting unit 75' of Fig. 7E is shaped such that it can be fitted between the dashboard 74 and the windshield 71, which can simplify positioning of the lighting unit 75'.

[0074] Fig. 7G shows that such a holographic marking 13 can also be arranged in a side window 78, for example, in a vehicle door 79. This can also be done without an associated main hologram. Parts of the vehicle door 79 can serve as a shadow, so that the holographic marking 13 is not visible to vehicle occupants. This holographic marking can, for example, contain various information about the vehicle and / or the window, as is conventionally printed or stamped onto the window.

[0075] The marking can then be read by a lighting device 75, for example by a service technician, as shown in Fig. 7H.

[0076] Fig. 7I shows the use of a larger-area holographic marking 13 for marking stone chip areas, i.e. areas in which a stone chip is particularly critical, in the windshield 71. The large-area marking does not bother a driver of the vehicle because they cannot perceive it. This is another example of a holographic marking that can also be used without a main hologram. With this and other markings, wavelengths in the non-visible range, e.g. infrared, can be used for reading with a suitable sensor (e.g. sensor 77). Additionally or alternatively, the viewing angle can be such that it does not occur during normal operation of the vehicle, e.g. when driving, for example a viewing angle approximately vertically upwards or to the side.In particular, the viewing angle for reading and / or an illumination angle for illuminating the holographic marking may be different from normal viewing directions when driving the vehicle, e.g. in a range of 60° to 120°, 75° to 105° or approximately 90° to such normal viewing directions.

[0077] Devices as described above can be manufactured using master plates. To manufacture devices as described above, the master plate is then placed adjacent to a holographic material (e.g., a photopolymer coated on a carrier film), and the holographic material is exposed using the master plate. This will be explained in more detail later.

[0078] Figure 8 shows an embodiment of a master plate 80. The master plate 80 has a master hologram 81 and a holographic diffuser 82. The master hologram 81 serves to produce, i.e., expose, a respective main hologram, such as the main hologram 12 of the embodiments described above. This can be done using any conventional method for hologram production.

[0079] The holographic diffuser 82 is used to imprint holographic markings, such as the holographic markings 13 (13A-13C) shown in the preceding figures. For this purpose, a corresponding pattern (corresponding to the desired marking) is written into the holographic material using a modulated light beam 83. As explained further below, the light beam 83 can be modulated, for example, by a spatial light modulator such as a liquid crystal display (LCD) or a digital micromirror device (DMD), or a corresponding pattern can be scanned.

[0080] This is shown in more detail in Fig. 9, where a corresponding pattern written by the light beams 83 (here three crosses and an "F") is visibly displayed. In this way, markings can be generated dynamically, i.e., the generated marking can vary depending on the modulation of the light beam 83, while the main hologram, generated by the master hologram 81, exhibits a static function.

[0081] Fig. 10 shows a variant. Here, the diffuser 82 is present as a flat diffuser only in one area, in which variable markings can be generated using the light beam 83 by modulation as described above. Such variable markings can be, for example, serial numbers or other markings that vary from device to device during production. In another area 1000, the diffuser already has a fixed shape as shown, so that holographic markings with the fixed shape shown are imprinted into the holographic material. Such markings, which are then present in all devices, can be, for example, alignment marks that are generally required for production.

[0082] Figure 11 illustrates a device manufacturing apparatus as described above with reference to Figures 1 to 7, using the master plate 80 and the holographic diffuser 82 of Figures 8 to 10. A light source 1100, for example a laser light source of the desired wavelength, generates illumination light, which is expanded and collimated via an optics 1101 and directed onto a corresponding mask 1102, shown here as an LCD display. The desired marking can then be displayed on the LCD display, which is thus exposed via the holographic diffuser 82 into a holographic material (not shown in Figure 11).

[0083] As already mentioned, the holographic diffuser 82 can be configured as a transmission diffuser or a reflection diffuser, and accordingly, the master hologram 81 can be configured as a reflection hologram or a transmission hologram. Depending on the configuration, the arrangement for exposing the holographic material differs. This will now be explained with reference to Figures 12-15.

[0084] Fig. 12 shows an arrangement with a holographic reflection diffuser 82. Here, a holographic material 1200, for example a photopolymer on a carrier, is arranged between the illumination, represented here by the mask 1102 of Fig. 11, and the master plate 80. The illumination light passes through the holographic material 1200 to the holographic diffuser 82 and is then diffracted for exposure onto the holographic material 1200. For simplicity, this is also referred to here as reflection, wherein it is a diffraction at the structures of the holographic diffuser 82. Glass 1201 can be arranged below the holographic diffuser 82, which serves to protect the holographic material 1200 and the carrier from environmental influences.

[0085] Fig. 13 shows a resulting device in which a main hologram 1302 was exposed through the master hologram 81 and markings 1300 were exposed by means of the diffuser 82. Here, the "visualization" of the markings 1300 also occurs in reflection, i.e., illumination light 1301 is irradiated from the same side from which the markings are viewed.

[0086] Figure 14 shows a transmission arrangement. Here, the master plate 80 is arranged between the holographic material 1200 and the illumination arrangement, again represented by the mask 1102, and the holographic material 1200 is illuminated through the master plate 80. A portion of the illumination light that passes undiffracted through the master plate (0th order) serves as the reference beam, and a portion of the illumination light diffracted by the master plate 80 (1st order) serves as the object beam. A glass 1401 can be provided above the master plate 80, as shown, which serves the same purpose as the glass 1201 of Figure 12.

[0087] Figure 15 shows a resulting device. A main hologram 1502 was created by exposure through the master hologram 81, and markings 1500 were created by exposures via the holographic diffuser 82. To view the markings 1500, they are illuminated from the same side as during exposure with illumination light 1501. Viewing occurs from the opposite side, i.e., in transmission. As shown in Figures 12 and 14, the exposure of the main hologram and the holographic markings can be performed in one step, i.e., the main hologram is also exposed via the respective master hologram 81 in the same arrangement.

[0088] In the above figures, the holographic diffuser 82 is shown only on one side of the master hologram 81. However, multiple areas of holographic diffusers may also be provided, for example, to provide holographic markings on different sides of the main hologram. A possible manufacturing process for the master plate will now be explained with reference to Figures 16 and 21.

[0089] First, as shown in Fig. 16, holographic diffusers 82 and the master hologram 81 are exposed onto separate photopolymer films. Position markings are printed on each of them, for example, using an inkjet technique. The position markings for the master hologram are designated by reference numeral 1600, and those for the diffusers 82 (e.g., transmission diffuser or reflection diffuser) are designated by reference numeral 1601. This results in a layer stack as shown in Fig. 17 with a carrier polymer 1700 and a photopolymer 1701, into which the diffusers 82 and the master hologram 81, respectively, are exposed (each in separate units).

[0090] In a next step, shown in Fig. 18, the diffusers 82 are laminated together with the master hologram 81 onto a glass plate 1800. Spacers 1801 are also laminated onto the glass plates. The position markings 1600, 1601 serve to precisely align the diffusers 82 and the master hologram 81 with each other. In other embodiments, the placement is performed mechanically, but without correction based on the position markings 1600, 1601, and the position of the position markings 1601 relative to the position markings 1600 is measured after lamination, so that the spatial relationship of the diffusers 82 to the master hologram 81 is known and can be used, for example, for later exposure and / or readout.

[0091] Fig. 19 shows a corresponding layer stack after lamination of Fig. 18, where the carrier polymer 1700 with the photopolymer 1701 (in separate sections for diffuser 82 and master hologram 81) are arranged on the glass plate 1800. The glass plate 1800 can, for example, have a thickness in the range of 1 mm, for example between 0.8 mm and 1.3 mm, for example approximately 1.1 mm. The glass plate 1800 serves as a carrier for the photopolymer 1701 and can later face an exposure beam during exposure.

[0092] In the next step, a thicker glass plate 2000, for example with a thickness between 3 mm and 10 mm, is applied to the device on the side opposite the glass plate 1800, together with an optical adhesive (e.g. OCA, optically clear adhesive) or a liquid optical adhesive (kit), as shown in Fig. 20, wherein the spacers 1801 protect the master hologram 81 and the diffusers 82 in this step. The glass plate 2000 serves to provide stability to the entire master plate and therefore has a corresponding thickness to ensure this stability. The corresponding layer stack can be seen in Fig. 21, wherein, compared to Fig. 19, the glass plate 2000 is also applied to the remaining layer stack by means of the optical adhesive 2100.

[0093] Fig. 22 then shows the production of a corresponding device with a corresponding production device as explained above with reference to Figs. 1-7. The production device has a holder for a master plate 2201, wherein the master plate 2201 corresponds to the master plate shown in Fig. 20. Furthermore, the production device has an illumination device 2200. For production, a photopolymer 2203, optionally with a carrier film, is first laminated to an underside of the master plate 2201. Markings 2204 are then exposed via the exposure module 2200 using laser light 2202, for example, red laser light. In this way, for example, position markings, identification numbers, or other markings can be exposed as explained above.At the same time, the master hologram can be exposed by a separate exposure module, or the exposure module 2200 contains additional light sources for exposing the main hologram over the master hologram, or the exposure module 2200 is moved accordingly to also expose the main hologram.

[0094] During the exposure process, a corresponding layer stack as shown in Fig. 23 contains, in addition to the layer stack of Fig. 21, the holographic material, in the case of Fig. 23 a photopolymer 2301 on a carrier film 2302.

[0095] The exposure module 2022 can be constructed similarly to that shown in Fig. 11, i.e., with a light source 1100, an optical system 1101, and a mask 1102. In the case of a micromirror array, an LC display, or another controllable device as a mask, the exposure module can additionally contain a controller that receives, for example, data via an interface describing a marking to be exposed and then controls the mask accordingly to generate spatially modulated illumination light. In the above device, the diffuser of the master plate is illuminated in transmission. The function of the diffuser is explained in Fig. 24. Here, a diffuser 2400, which can be, for example, the diffuser 82 of the figures above, is illuminated at an angle of 6° to the vertical, which is then diffracted onto the holographic material at a scattering angle of, for example, 0.5°.The relatively steep angle of incidence of 6° or less can lead to a low parallax error in the exposed holographic markings and also to a small installation space requirement. Exposure can be performed, for example, with a wavelength of 635 nm (red laser light). By using a transmission diffuser, the wavelength range that can be used to make the markings visible is relatively large (i.e.

[0096] Wavelengths of the illumination light 20 from Figs. 2-6), and, for example, infrared light with a wavelength of 850 nm can be used for readout. However, other angles for illuminating the diffuser, e.g., greater than 6°, can also be used. In general, the wavelength and angle selectivity of a transmission hologram are lower than those of a reflection hologram, although the latter, in particular, is still retained. For example, a transmission hologram illuminated with red light, e.g., laser light, can be read out with daylight.

Claims

Patent claims 1. A device comprising: a holographic material (2301), at least one holographic mark (13) provided in the holographic material (2301), a main hologram (12) provided in the holographic material (2301), wherein the holographic mark (13) is only sensitive to light of a predetermined wavelength, wherein the main hologram (12) is sensitive to light that lies outside the predetermined wavelength.

2. Device comprising: a holographic material (2301), at least one holographic Marking (13), a main hologram (12) provided in the holographic material (2301), wherein the holographic marking (13) is only sensitive to light from a predetermined direction, wherein the main hologram (12) is sensitive to light coming from a direction other than the predetermined direction.

3. Device comprising: a holographic material (2301), at least one holographic Marking (13), a main hologram (12) provided in the holographic material (2301), wherein the holographic marking (13) is arranged to diffract light only in a further predetermined direction, wherein the main hologram (12) is arranged to diffract light in a direction other than the further predetermined direction.

4. Device according to one of the preceding claims, wherein the at least one holographic marking (13) is arranged in the device in such a way that it does not can be illuminated with light from the given direction and / or cannot be viewed from the further given direction.

5. Device according to one of claims 1 to 3, wherein the at least one holographic marking (13) is arranged in the device such that, in a predetermined normal use of the device, it cannot be illuminated with light from the predetermined direction and / or cannot be viewed from the further predetermined direction.

6. Device according to claim 5, wherein the holographic marking is viewable by means of a separate mobile lighting unit (75).

7. Device according to one of claims 4 to 6, wherein the holographic material is arranged on or in a window (71, 78) of a vehicle.

8. The device according to claim 7, further comprising an illumination device for the main hologram (12) arranged in a dashboard (74) of the vehicle.

9. Device according to one of claims 5 or 6 and according to one of claims 7 or 8, wherein the normal use of the device is the use of the vehicle by a driver.

10. Device according to one of claims 7 to 9, wherein the pane (71, 78) is a windshield (71) or a side window (78).

11. Device according to one of claims 7 to 10, wherein the holographic marking (14) marks a predetermined area of ​​the disc (71, 78).

12. Device according to one of claims 1-11, wherein the at least one holographic marking (13) comprises a volume hologram.

13. Device according to one of claims 1-12, wherein an area of ​​the main hologram (12) is at least twice as large as an area of ​​the at least one holographic marking (13).

14. Device comprising: a holographic material (2301), at least one holographic marking (13) provided in the holographic material (2301) as a volume hologram, wherein: -the holographic marking (13) is only sensitive to light of a given wavelength, and / or -the holographic marking (13) is only sensitive to light from a given direction, and / or -the holographic marking (13) is arranged to diffract light only in a further predetermined direction.

15. The apparatus of claim 14, further comprising a main hologram (12) provided in the holographic material, wherein: - the main hologram (12) is sensitive to light outside the specified wavelength, and / or - the main hologram (12) is sensitive to light coming from a direction other than the predetermined direction, and / or, - the main hologram (12) is designed to diffract light in a direction other than the further predetermined direction.

16. Device according to claim 14 or 15, wherein the at least one holographic marking (13) is arranged in the device such that it cannot be illuminated with light from the predetermined direction and / or cannot be viewed from the further predetermined direction.

17. Device according to claim 14 or 15, wherein the at least one holographic marking (13) is arranged in the device such that, in a predetermined normal use of the device, it cannot be illuminated with light from the predetermined direction and / or cannot be viewed from the further predetermined direction.

18. Device according to one of the preceding claims, wherein the marking (13) comprises one or more marking elements from a group consisting of: -an adjustment mark, -a numbering, -a QR code, -a UGI code, -a safety marking, -a brand, -a logo, -a test mark, -a process parameter, -a price label 19. Device according to one of the preceding claims, wherein the holographic marking (13) occupies less than 20% of the area of ​​the holographic material (2301).

20. Device comprising: a holographic material (2301) arranged on or in a window (71, 78) of a vehicle, at least one holographic marking (13) provided in the holographic material (2301), wherein the holographic marking (13) is only sensitive to light from a predetermined direction and / or is only viewable from a further predetermined direction, wherein the at least one holographic marking (13) is arranged in the device such that it cannot be illuminated with light from the predetermined direction and / or cannot be viewed from the further predetermined direction during a predetermined normal use of the device.

21. A vehicle comprising the device according to any one of claims 1 to 20.

22. The vehicle of claim 21, wherein the vehicle does not have an illumination device for illuminating the holographic marking (14).

23. Master plate (2201) for producing a device, in particular for producing the device according to one of claims 1-19, comprising a first hologram region for writing a holographic marking (13) in a holographic material (2301).

24. The master disk (2201) of claim 23, wherein the first hologram region comprises a holographic diffuser (82).

25. Master plate (2201) according to claim 23 or 24, wherein the holographic diffuser (82) has a shape of the marking (13) at least in one area (1000).

26. Master plate (2201) according to one of claims 23-25, wherein the holographic diffuser (82) is formed flat in at least one region.

27. Master plate (2201) according to any one of claims 23-26, further comprising a second hologram region (81) for writing a main hologram (12) into the holographic material.

28. Master plate (2201) according to claim 27, wherein the first hologram region and the second hologram region (81) are mounted separately on a carrier plate (1800) of the master plate (2201).

29. A method for producing the device according to any one of claims 1-19 using the master plate (2201) according to any one of claims 23-28, comprising - arranging the master plate (2201) adjacent to a holographic material (2301), and - Exposing the master plate to write the mark (13) into the holographic material (2301).

30. The method of claim 29, wherein the exposing comprises exposing through a mask element (1102), the mask element determining a shape of the mark (13).

31. Manufacturing apparatus for manufacturing the device according to any one of claims 1-19, comprising a holder for the master plate (2201) according to any one of claims 23-28 and an exposure module (2200) for writing the mark (13) in a holographic material (2301) by means of the first hologram area of ​​the master plate.

32. A method for reading the holographic marking (14) of the device according to any one of claims 1 to 20, comprising: Arranging a mobile illumination device (75, 75') near the holographic marking (14), and illuminating the holographic marking (14) in order to read the holographic marking (14).

33. The method according to claim 32, wherein a positioning of the mobile lighting device (75, 75') during placement is determined by a geometry of a system in which the device is provided and a geometry of the lighting device (75, 75').

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