DE102023135327A1 - Device with holographic marking, master plate for producing such a device, and corresponding methods - Google Patents

Abstract

Devices comprising a holographic material and a holographic marking (13) provided in the holographic material are described. The holographic marking (13) is only sensitive to light of a predetermined wavelength and/or to light from a predetermined direction, and/or is configured to diffract light only in a further predetermined direction. The device can further comprise a main hologram (12). In addition, corresponding master plates for producing such devices, methods, and manufacturing devices are described.

Description

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

Different types of markings are used for different products, i.e., devices. These can be markings required during product manufacturing, such as alignment marks. These are used for alignment and positioning during device manufacturing. Other examples are markings for traceability, such as article numbers, batch/lot numbers, serial numbers, or UDI (unique device identifier) codes.

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

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.

Conventional markings are printed, embossed, punched, laser-etched, or applied to the devices using an adhesive label. Thermal processes are also possible.

Holographic markings are also used for some purposes. Examples can be found in the DE 10 2007 061 626 A1 , the DE 4 124 203 A1 , the DE 10 2014 117 511 A1 , the DE 10 2017 211 914 A1 , the EP 3 955 051 A1 , the US 2020 / 0 301 157 A1 , or the DE-OS 1 963 787 .

It is a task to create improved opportunities in this regard.

An apparatus according to claim 1, 2, 3 or 6, a master disk according to claim 10, a method according to claim 17 or a manufacturing apparatus according to claim 19 are provided. The subclaims define further embodiments.

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.

• - nur sensitiv auf Licht einer vorgegebenen Wellenlänge und/oder
• - nur sensitiv auf Licht aus einer vorgegebenen Richtung, und/oder
• - eingerichtet, Licht nur in eine weitere vorgegebene Richtung zu beugen.

The holographic marking is

• - only sensitive to light of a given wavelength and/or
• - only sensitive to light from a given direction, and/or
• - designed to bend light only in one further specified direction.

• - sensitiv auf Licht, das außerhalb der vorgegebenen Wellenlänge liegt (wobei es auch zusätzlich sensitiv auf Licht der vorgegebenen Wellenlänge sein kann), und/oder
• - sensitiv auf Licht, das aus einer anderen Richtung als die vorgegebene Richtung kommt (auch hier kann es zusätzlich sensitiv auf Licht sein, das aus der vorgegebenen Richtung kommt), und/oder
• - eingerichtet, Licht in eine andere als die weitere vorgegebene Richtung zu beugen (und es kann zusätzlich auch Licht in die vorgegebene Richtung beugen).

The main hologram, however, is:

• - sensitive to light outside the specified wavelength (it may also be additionally sensitive to light of the specified wavelength), and/or
• - sensitive to light coming from a direction other than the specified direction (here too, it can additionally be sensitive to light coming from the specified direction), and/or
• - designed to bend light in a direction other than the further specified direction (and it can also bend light in the specified direction).

"Sensitive" means that the respective hologram (holographic marking or main hologram) only diffracts the light according to the respective hologram's function when irradiated with light with the respective property (wavelength and/or direction), for example to create an image. Otherwise, the light is diffracted or not diffracted in a way that does not fulfill the function. 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 specified wavelength can be a wavelength range around a central wavelength, and the specified direction and/or the further specified direction can be a directional range, for example, a club-shaped one.

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.

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 diffracts light only in a further 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.

• - einer Justagemarkierung, d.h. eine Markierung, die zum Ausrichten verschiedener Komponenten oder Vorrichtungen zueinander dienen kann,
• - einer Nummerierung, beispielsweise eine fortlaufende Produktnummerierung,
• - einem QR-Code, in dem beliebige Informationen codiert sein können,
• - ein UDI-Code, d.h. ein eindeutiger alphanumerischer oder numerischer Code für ein Medizinprodukt,
• - einer Sicherheitsmarkierung, wie beispielsweise ein Warnhinweis,
• - einer Marke
• - einem Logo
• - einem Prüfkennzeichen, wie beispielsweise ein CE-Prüfkennzeichen,
• - einem Prozessparameter,d.h. Informationen über einen Parameter, der während der Herstellung eines Produkts verwendet wurde, und
• - einer Preiskennzeichnung, die einen Preis eines Produkts angibt.

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

• - an alignment mark, i.e. a mark that can be used to align different components or devices with each other,
• - a numbering, for example a consecutive product numbering,
• - a QR code in which any information can be encoded,
• - a UDI code, i.e. a unique alphanumeric or numeric code for a medical device,
• - a safety marking, such as a warning notice,
• - a brand
• - a logo
• - a test mark, such as a CE test mark,
• - a process parameter, i.e. information about a parameter used during the manufacture of a product, and
• - a price label that indicates a price of a product.

The holographic marking can occupy 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 for producing a device, in particular a device as described above, is provided. 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 purpose, a light beam, typically a laser light beam, is split into an object beam and a reference beam. The object beam is diffracted by the master plate and then caused to interfere with the reference beam in a photosensitive material, whereby the hologram is exposed into the photosensitive material.

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 a fixed mark is written with the first part and another mark (such as a serial number or the like) can be written over the second part.

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.

The master plate can further include a second hologram region for writing the above-mentioned 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.

Using such a master plate, a device as described above can be manufactured by arranging the holographic material adjacent to the master plate and then exposing the master plate to write the marking into the holographic material. In the case of 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.

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

• 1 eine schematische Darstellung einer Vorrichtung gemäß einem Ausführungsbeispiel,
• 2A, 2B, 3A, 3B, 4A, 4B, 5A, 5B, 6A, 6B, verschiedene Eigenschaften von holografischen Markierungen verschiedener Ausführungsbeispiele,
• 7A und 7B veranschaulichen eine Abschattung bei manchen Ausführungsbeispielen,
• 8, 9 und 10 Masterplatten gemäß verschiedener Ausführungsbeispiele,
• 11 eine Herstellungsvorrichtung gemäß einem Ausführungsbeispiel,
• 12 eine Darstellung eines Belichtungsvorgangs mit einer Masterplatte in Transmission,
• 13 eine mit der Belichtung der 12 hergestellte Vorrichtung,
• 14 eine Darstellung eines Belichtungsvorgangs mit einer Masterplatte in Reflexion,
• 15 eine mittels des Belichtungsvorgangs der 14 hergestellte Vorrichtung,
• 16-21 Darstellungen zur Erläuterung der Herstellung einer Masterplatte,
• 22 eine Herstellungsvorrichtung gemäß einem Ausführungsbeispiel,
• 23 ein Schichtstapel in der Herstellungsvorrichtung der 22, und
• 24 ein Diagramm zur Herstellung der Wirkungsweise eines holografischen Diffusors in verschiedenen Ausführungsbeispielen.

Various embodiments are explained in more detail below with reference to the accompanying drawings. They show:

• 1 a schematic representation of a device according to an embodiment,
• 2A , 2B , 3A , 3B , 4A , 4B , 5A , 5B , 6A , 6B , different properties of holographic markings of different embodiments,
• 7A and 7B illustrate shading in some embodiments,
• 8 , 9 and 10 Master plates according to various embodiments,
• 11 a manufacturing device according to an embodiment,
• 12 a representation of an exposure process with a master plate in transmission,
• 13 one with the exposure of the 12 manufactured device,
• 14 a representation of an exposure process with a master plate in reflection,
• 15 one by means of the exposure process of the 14 manufactured device,
• 16-21 Illustrations to explain the production of a master plate,
• 22 a manufacturing device according to an embodiment,
• 23 a layer stack in the manufacturing device of the 22 , and
• 24 a diagram for the production of the mode of operation of a holographic diffuser in various embodiments.

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 symbols in the figures denote the same or corresponding elements, which are also not explained in more detail.

The device of 1 comprises a carrier 11 with holographic material, into which at least one holographic marking 13 has been etched. Furthermore, a main hologram 12 has been etched 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, wherein the main hologram 12 and the holographic marking 13 are etched into the photopolymer. While in the 1 While a single holographic marking 13 is shown, multiple holographic markings may be provided, even for different purposes (e.g., alignment marks, product codes, logos, trademarks, etc. as explained above).

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 corresponding direction. Such angles and wavelengths are determined when the holographic marking 13 is embossed into the holographic material by using light of a corresponding wavelength for exposure, and by irradiating the object and reference waves at corresponding angles. It should be noted that "light" in this sense is not limited to the visible range; for example, markings can also be embossed using infrared or ultraviolet light, which can then only be viewed with infrared or ultraviolet light.

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

This will now be done with reference to the 2-6 , each comprising a sub-figure A and a sub-figure B, are explained in more detail.

In the 2-6 As an example, three holographic markings 13A-13C in the form of crosses, for example as alignment markings, are shown together with a main hologram 12 on a carrier 11.

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

3A and 3B illustrate the wavelength selectivity. The 3A corresponds to the 2A , that is, 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 the image 15. In the 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.

The 4A and 4B illustrate the angular selectivity of the illumination. The 4A corresponds to the 2A and 3A , that is, the illumination is carried out with the illumination light 20 with the correct angle and wavelength, and the markings 13A-13C are visible in the image 15. In the 4B The illumination is performed with illumination light 40 having the same wavelength as illumination light 20 (i.e., the correct wavelength), but at a different angle. Here, the markings in image 15 are not visible.

The 5A and 5B illustrate the selectivity with respect to the direction of observation, i.e. the direction in which light is diffracted by the markings 13A-13C and thus the markings are visible. 5A corresponds to the 2A , 3A and 4A , in which the illumination is provided by the illumination light 20 and the camera 14 is arranged as in the previous figures. In the 5B The camera 14 is now positioned 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. The tolerance regarding the direction of observation 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 regarding the direction of observation. For example, the permissible tolerance range can be reduced when positioning a camera that reads the marking.

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

In the above examples, the light pattern generated by the main hologram 12 is always visible in the respective subfigures "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.

Some markings are only required during the manufacturing process of the device, but not during subsequent 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 no longer required. In such cases, the 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 be achieved due to shadowing. This is described in the 7A and 7B illustrated.

The 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. The 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 and thus the observer 14 can no longer perceive the marking.

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 disposed on a carrier film), and the holographic material is exposed using the master plate. This will be explained in more detail later.

The 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.

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.

This will be explained in more detail in 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.

The 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 by means of light beam 83 through modulation as described above. Such variable markings can be, for example, serial numbers or other markings that change from device to device during manufacture. In another area 1000, the diffuser already has a fixed shape as shown, so that holographic markings with the fixed shape shown are etched into the holographic material. Such markings, which are then present in all devices, can be For example, adjustment marks that are generally required for production.

The 11 illustrates a manufacturing device for devices as above with reference to the 1 to 7 described by means of the master plate 80 and the holographic diffuser 82 of the 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 LC display. The desired marking can then be displayed on the LC display, which is thus projected via the holographic diffuser 82 into a (in 11 holographic material (not shown) is exposed.

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

The 12 shows an arrangement with a holographic reflection diffuser 82. Here, a holographic material 1200, for example a photopolymer on a carrier, is placed between the illumination, here represented by the mask 1102 of the 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.

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 takes place in reflection, i.e., illumination light 1301 is irradiated from the same side from which the markings are viewed.

The 14 shows an arrangement in transmission. 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 exposed through the master plate 80. A portion of the illumination light that passes undiffracted through the master plate (0th order) serves as a reference beam, and a portion of the illumination light diffracted by the master plate 80 (1st order) serves as an 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 the 12 .

The 15 shows a resulting device. A main hologram 1502 was generated by exposure through the master hologram 81, and markings 1500 by exposures via the holographic diffuser 82. To view the markings 1500, illumination is applied from the same side as during exposure with illumination light 1501. Viewing is performed from the opposite side, ie, in transmission. As shown in the 12 and 14 As shown, the exposure of the main hologram and the holographic markings can be carried out in one step, i.e. the main hologram is also exposed over the respective master hologram 81 in the same arrangement.

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 described with reference to the 16 and 21 explained.

First, as in 16 As shown, holographic diffusers 82 and the master hologram 81 are exposed onto separate photopolymer films. Position markings are printed, 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 (for example, transmission diffuser or reflection diffuser) are designated by reference numeral 1601. This results in a layer stack as shown in 17 with a carrier polymer 1700 and a photopolymer 1701, into which the diffusers 82 and the master hologram 81 are exposed (each in separate units).

In a next step, which will be 18 As shown, the diffusers 82 are laminated together with the master hologram 81 onto a glass plate 1800. In addition, spacers 1801 are 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.

The 19 shows a corresponding layer stack after lamination of the 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.

In the next step, a thicker glass plate 2000, for example with a thickness between 3mm and 10mm, 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 20 is shown, 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 is shown in 21 to see, where compared to the 19 the glass plate 2000 is still applied to the remaining layer stack by means of the optical adhesive 2100.

The 22 then shows the manufacture of a corresponding device with a device as described above with reference to the 1-7 explained by means of a corresponding manufacturing device. The manufacturing device has a holder for a master plate 2201, wherein the master plate 2201 of the 20 shown master plate. 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. Then, the exposure of markings 2204 takes place 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.

During the exposure process, a corresponding layer stack as shown in 23 shown, in addition to the layer stack of the 21 nor the holographic material, in the case of the 23 a photopolymer 2301 on a carrier film 2302.

The exposure module 2022 can be used similarly to the 11 shown, that is to say with a light source 1100, an optics 1101 and a mask 1102. In the case of a micromirror arrangement, an LC display or another controllable device as a mask, the exposure module can additionally contain a controller which, for example, receives data via an interface which describes a marking to be exposed and then controls the mask accordingly in order to generate correspondingly spatially modulated illumination light.

In the above setup, the diffuser of the master plate is illuminated in transmission. The function of the diffuser is 24 explained. 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 small parallax error in the exposed holographic markings and also to a small installation space requirement. The exposure can, for example, be carried out 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., wavelengths of the illumination light 20 from the 2-6 ), and infrared light with a wavelength of 850 nm, for example, 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 that of a reflection hologram, although the latter, in particular, is still retained. For example, a transmission hologram exposed to red light, e.g., laser light, can be read out using daylight.

QUOTES CONTAINED IN THE DESCRIPTION

This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10 2007 061 626 A1 [0006]
• DE 4 124 203 A1 [0006]
• DE 10 2014 117 511 A1 [0006]
• DE 10 2017 211 914 A1 [0006]
• EP 3 955 051 A1 [0006]
• US 2020 / 0 301 157 A1 [0006]
• DE-OS 1 963 787 [0006]

Claims (19)

Device comprising: a holographic material (2301), at least one holographic marking (13) provided in the holographic material (2301), a main hologram (12) provided in the holographic material (2301), wherein the holographic marking (13) is only sensitive to light of a predetermined wavelength, wherein the main hologram (12) is sensitive to light outside the predetermined wavelength A device comprising: a holographic material (2301), at least one holographic marking (13) provided in the holographic material (2301), 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. A device comprising: a holographic material (2301), at least one holographic marking (13) provided in the holographic material (2301), a main hologram (12) provided in the holographic material (2301), wherein the holographic marking (13) is configured to diffract light only in a further predetermined direction, wherein the main hologram (12) is configured to diffract light in a direction other than the further predetermined direction. Device according to one of the Claims 1 - 3 , wherein the at least one holographic marking (13) comprises a volume hologram. Device according to one of the Claims 1 - 4 , 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). A device comprising: a holographic material (2301), at least one holographic marking (13) provided as a volume hologram in the holographic material (2301), wherein: - the holographic marking (13) is only sensitive to light of a predetermined wavelength, and/or - the holographic marking (13) is only sensitive to light from a predetermined direction, and/or - the holographic marking (13) is configured to diffract light only in another predetermined direction. Device according to Claim 6 , further comprising a main hologram (12) provided in the holographic material, wherein: - the main hologram (12) is sensitive to light that lies outside the predetermined wavelength, and/or - the main hologram (12) is sensitive to light that comes from a direction other than the predetermined direction, and/or, - the main hologram (12) is arranged to diffract light in a direction other than the further predetermined direction. Device according to one of the preceding claims, wherein the marking (13) comprises one or more marking elements from a group consisting of: - an alignment mark, - a numbering, - a QR code, - a UGI code, - a security mark, - a brand, - a logo, - a test mark, - a process parameter, - a price marking 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). Device according to one of the preceding claims, 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. Master plate (2201) for producing a device, in particular for producing the device according to one of the Claims 1 - 10 comprising a first hologram region for writing a holographic mark (13) in a holographic material (2301). Master plate (2201) after Claim 11 , wherein the first hologram region has a holographic diffuser (82). Master plate (2201) after Claim 11 or 12 , wherein the holographic diffuser (82) comprises at least in an area (1000) has a shape of the marking (13). Master plate (2201) after one of the Claims 11 - 13 , wherein the holographic diffuser (82) is flat in at least one region. Master plate (2201) after one of the Claims 11 - 14 , further comprising a second hologram region (81) for writing a main hologram (12) into the holographic material. Master plate (2201) after Claim 15 , wherein the first hologram region and the second hologram region (81) are mounted separately on a carrier plate (1800) of the master plate (2201). Method for producing the device according to one of the Claims 1 - 11 by means of the master plate (2201) according to one of the Claims 11 - 16 , 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). Procedure according to Claim 17 , wherein the exposing comprises exposing through a mask element (1102), the mask element determining a shape of the mark (13). Manufacturing device for manufacturing the device according to one of the Claims 1 - 10 , comprising a holder for the master plate (2201) according to one of the Claims 11 - 16 and an exposure module (2200) for writing the mark (13) in a holographic material (2301) using the first hologram area of the master plate.

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