DEVICE FOR PRODUCING HOLOGRAMS USING THE CONTACT COPY METHOD WITH HIGH DIFFRACTION EFFICIENCY

Description

[0001] The invention relates to a device for producing holograms using the contact copying process, in particular holograms with a high diffraction efficiency.

[0002] Valuable and / or security documents incorporate features intended to ensure the verifiability of the authenticity and authenticity of the respective valuable and / or security document. Such features are referred to as security features.

[0003] Holograms represent a group of security features used for this purpose. Holograms can basically be divided into two different categories. Firstly, there are so-called thin holograms, in which the holographic information is stored in a layer whose layer thickness is on the order of magnitude of the wavelength of the light or electromagnetic radiation with which the hologram can be reconstructed. The holographic information is often stored on the surface in the form of a surface relief. These holograms are then referred to as surface holograms. Another class of holograms, known as thick holograms, store the holographic information in the volume of a recording material, with the layer thickness of the storage area corresponding to a multiple of the wavelength of the light or electromagnetic radiation with which the hologram can be reconstructed.These holograms are also called volume holograms.

[0004] While surface holograms can be embossed into plastic layers, for example, volume holograms are stored in a photosensitive material by means of exposure. A manufacturing process for producing volume reflection holograms in particular uses a hologram master in front of which a holographic recording material is arranged. When the hologram is recorded or exposed into the holographic recording material, coherent light is irradiated through the holographic recording material onto the hologram master, which at least partially reflects the light, for example, reflects it or diffracts it in reflection. In the holographic recording material, this light reflected by the hologram master, e.g., diffracted or reflected in reflection, interferes with the coherent light that is irradiated through the recording material onto the hologram master.The interference pattern formed in the hologram recording material is stored in the hologram recording material, which is usually a photosensitive material, particularly preferably a photopolymer. The physical and / or chemical changes in the photosensitive material are subsequently fixed, rendering the photosensitive material insensitive to radiation and allowing the hologram to be reconstructed upon exposure to light.

[0005] US 2003 / 179242 A1 discloses an image exposure recorder for recording a holographic stereogram image or a hologram image on a hologram recording medium. The recorder has an inverse correction system for rotating the polarization plane of a reference light using a half-wave plate, directing the reference light onto a hologram recording medium, and measuring the intensity of a portion of the reference light transmitted through a polarizer from the reference light transmitted through a portion of the surface of the hologram recording medium using a photodetector. In the inverse correction system, the angle of rotation of the half-wave plate is determined such that the intensity of the reference light determined by the photodetector can be minimal or maximal.Therefore, the deterioration of the coherence between the object light and the reference light due to the transmission of the object and reference light through the hologram recording medium with birefringence is prevented, thus producing a holographic stereogram for reproducing a bright holographic stereogram image.

[0006] JP2007041360A discloses controlling the temperature of a hologram recording medium without increasing power consumption. The interior of a housing is heated by heat generated by a laser light source or a circuit board. When the temperature inside the housing rises above a predetermined temperature range, a control circuit operates an air-cooling fan to expel warm air inside the housing to the outside, thus maintaining the temperature inside the housing within the predetermined range, thereby maintaining a cartridge-type hologram recording medium within a predetermined temperature range. A hologram is then recorded and reproduced using the cartridge-type hologram recording medium. This means that by utilizing the waste heat from heat-generating components, the temperature of the hologram recording medium can be controlled without increasing power consumption.

[0007] DE 11 2006 002 839 B4 describes an arrangement of an electrical device of a hybrid vehicle and a cooling structure for the electrical device, wherein the cooling structure comprises: a plurality of coolant paths through which a coolant for the electrical device flows, an inlet into which the coolant to be supplied to the plurality of coolant paths flows, and a coolant distribution mechanism provided between the inlet and the plurality of coolant paths for promoting the distribution of the coolant to each of the coolant paths, wherein the coolant distribution mechanism has a wall extending in a direction intersecting an alignment direction of the inlet and the plurality of coolant paths, characterized in that the wall has a portion formed sothat a height thereof relative to a direction perpendicular to the alignment direction and perpendicular to the extension direction of the wall becomes lower with increasing distance from the inlet.,

[0008] Since the holographic recording material is preferably brought into contact with the hologram master during the exposure process in order to avoid relative movement of the recording material with respect to the hologram master, such an exposure process is also called a contact copying process.

[0009] In the state of the art, the holographic recording material is fed into and removed from the exposure process either in the form of sheets or as roll material.

[0010] The quality of the hologram produced in this way is reflected in the high diffraction efficiency of the hologram produced in the contact copying process. The higher the diffraction efficiency, the better the resulting copy. It is understood by those skilled in the art that the diffraction efficiency is partially limited by the quality of the hologram master. However, it has been shown that when producing a large number of holograms using the contact copying process, the quality of the resulting holograms varies. Such variation is undesirable for holograms intended for use as security features.

[0011] The invention is therefore based on the technical object of creating a device and a method for producing holograms using the contact copying process, which ensure the highest possible uniform diffraction efficiency of the holograms produced.

[0012] The object is achieved by a device having the features of patent claim 1 and a method having the features of patent claim 7. Advantageous embodiments of the invention emerge from the subclaims. Basic idea of ​​the invention

[0013] The invention is based on the fundamental idea that the reaction conditions in the holographic recording material must be kept as optimal as possible. While high thermal losses occur during the generation of coherent radiation, which is usually laser radiation, some of which are then introduced into a reaction chamber where the exposure of the recording material takes place, thermal changes occur in particular, which, according to the inventors' findings, are presumably responsible for the fluctuation and, in particular, a deterioration in diffraction efficiency during the production of a large number of holograms.Although it is known that a hologram master can also be subject to wear, the associated changes in diffraction efficiency are observed on a completely different, much larger time scale than the otherwise observed changes in diffraction efficiency of holograms produced using the contact copying process. Definitions

[0014] A volume hologram is a hologram in which the holographic information is stored in a volume region whose thickness is greater than several times the wavelength of the electromagnetic radiation with which the hologram can be reconstructed. Typically, the thickness of this layer corresponds to at least five to fifteen times the wavelength of the electromagnetic radiation used for recording.

[0015] Contact copying is a process for producing holograms in which a holographic recording material is placed adjacent to a hologram master.

[0016] In the production of volume reflection holograms, the electromagnetic radiation used for recording is radiated through the holographic recording material onto the hologram master, which reflects or reflectively diffracts a portion of this radiation back into the holographic recording material. The interference pattern created between the radiated electromagnetic radiation and the radiation reflected by the hologram master is stored in the holographic recording material in the form of local changes, particularly in the form of refractive index changes. This applies particularly to photopolymers. In other recording materials, storage can also take the form of blackening.

[0017] A hologram master is usually a volume reflection hologram itself and can be manufactured in any way. In other embodiments, however, the hologram master can also be a faceted surface, for example, a blazed grating or similar.

[0018] In yet other embodiments, the holograms produced can be transmission holograms produced using the contact copying process, in which the hologram master is transparent to the electromagnetic radiation used for exposure, and only a portion of the electromagnetic radiation is diffracted. In this case, the light is radiated through the hologram master into the holographic recording material arranged in contact with the hologram master on the side facing away from the irradiation side. Part of the electromagnetic radiation passing through the hologram master is not diffracted, while another part is diffracted. This again creates an interference pattern in the holographic recording material, forming a volume transmission hologram.

[0019] A reaction chamber is a room or chamber in which the exposure of the holographic recording material takes place. The reaction chamber is radiation-tight and sealed from the environment to prevent the ingress of ambient light or other radiation that could trigger changes in the holographic recording material. The radiation-tight shielding is also typically designed to prevent the ingress of dirt and dust particles into the reaction chamber, which could contaminate and / or damage the hologram master and / or the holographic recording material.

[0020] Light is considered to be electromagnetic dipole radiation whose wavelength lies in the visible wavelength range, the UV wavelength range or the IR wavelength range.

[0021] A heat pipe is a device for transporting heat, i.e. thermal energy. A working fluid is enclosed within the heat pipe, which is in a liquid state at one end. At this heated end, the working fluid absorbs thermal energy and thereby cools the area surrounding the heated end. The working fluid is thereby converted into a gaseous state and spreads through the heat pipe. At a cooled end, the working fluid releases thermal energy and undergoes a phase transition back to the liquid state. In a design known as a two-phase siphon, the working fluid then reaches the heated end driven by gravity. In a so-called heat pipe design, the working fluid is transported back via capillary forces.

[0022] A medium is transparent if, according to geometric optics, light can be imaged through the medium. In particular, the transparent medium does not significantly absorb light and does not diffusely scatter light. Light absorption in connection with exposure processes in a photosensitive material is not taken into account here. Preferred embodiments

[0023] The invention provides a device for producing holograms using the contact copying method, comprising a hologram master, a coherent light source for generating coherent light, a transport device for supplying and removing holographic recording material so that it is arranged adjacent to and in front of the hologram master for an exposure process, and a reaction chamber which surrounds the hologram master and protects the holographic recording material from ambient light and foreign material during the exposure process, wherein the coherent light of the coherent light source is radiated into the reaction chamber during the exposure process so that the coherent light radiates through the holographic recording material arranged adjacent to and in front of the hologram master and is at least partially reflected back at the master,so that, due to interference between the coherent light passing through the holographic recording material and the light at least partially reflected by the hologram master, changes are brought about inside the holographic recording material, forming a hologram, or so that the hologram master is irradiated, so that a portion of the coherent light passes through the hologram master unchanged and a further portion of the coherent light is deflected at the hologram master, so that, due to interference between the one unchanged portion of the coherent light and the further deflected portion of the coherent light, changes are brought about inside the holographic recording material arranged adjacent to and behind the hologram master, forming the hologram, wherein a cooling device is designed to dissipate heat from the reaction chamber,wherein at least one element of the cooling device is thermally conductively connected to the hologram master in order to cool the hologram master.

[0024] Furthermore, a method for producing holograms in a contact copying process is provided, which comprises: (a) Providing a hologram master in a reaction chamber that surrounds the hologram master and protects it from ambient light and foreign material, (b) Feeding holographic recording material into a reaction chamber that surrounds the hologram master so that the holographic recording material is arranged adjacent to the hologram master for an exposure process, (c) Carrying out an exposure process by generating coherent light and irradiating it into the reaction chamber so that the coherent light radiates through the holographic recording material arranged adjacent to the hologram master and is at least partially reflected back at the master, so that changes are brought about inside the holographic recording material due to interference between the coherent light radiating through the holographic recording material and the light at least partially reflected back by the hologram master, which changes form a hologram,or so that the hologram master is irradiated and a portion of the coherent light passes through the hologram master unchanged and a further portion of the coherent light is deflected at the hologram master, so that due to interference between the one altered portion of the coherent light and the further deflected portion of the coherent light, changes are brought about inside the holographic recording material arranged adjacent to the hologram master, which changes form the hologram, (d) removing the holographic recording material from the reaction chamber, characterized in that (e) heat is removed from the reaction chamber by means of a cooling device, wherein at least one element of the cooling device is connected to the hologram master in a heat-conducting manner in order to cool the hologram master.

[0025] By cooling the reaction chamber, the exposure process is ensured to run optimally at all times. Contrary to the assumption that exposure would be easier at higher temperatures and that the required light intensity to form the hologram in the holographic recording material would be lower, the inventors have discovered that excessively high temperatures and fluctuating temperatures in the reaction chamber lead to a decrease in the diffraction efficiency of the produced holograms and to fluctuations in the diffraction efficiency. By cooling the reaction chamber, holograms with consistently high diffraction efficiency can be produced using the contact printing process.

[0026] According to one embodiment, the cooling device flows a cooling fluid into the reaction chamber. Thus, the cooling fluid flowing into the reaction chamber is in gaseous form. Cooled, dry, dust-free air is preferably suitable for this purpose. However, other gases, such as CO2 or nitrogen, can also be used, particularly if the reaction chamber is designed to be gas-tight.

[0027] Preferably, the reaction chamber is designed such that the cooling fluid flows into the reaction chamber in a lower region.

[0028] Also preferably, the reaction chamber is designed such that heated cooling fluid flows out of the reaction chamber in an upper region thereof.

[0029] Particularly preferably, the cooling fluid is conducted in a closed circuit.

[0030] In a preferred embodiment, the cooled cooling fluid flows into the reaction chamber in a lower region and flows out of the reaction chamber in an upper region and is guided in a closed cooling circuit and cooled before flowing back into the reaction chamber in the lower region.

[0031] In another embodiment, it is provided that alternatively and / or additionally heat is dissipated from the reaction chamber using at least one heat pipe. In a preferred embodiment, the cooling device comprises at least one heat pipe. In a first section of a heat pipe that projects into the reaction chamber, there is a working medium in a liquid state. The working medium is heated via the walls of the heat pipe and thus extracts heat energy from the reaction chamber. As a result, the working medium is partially converted into a gaseous state and moves into a second region of the heat pipe. In this region, heat energy is again released via the surface of the heat pipe to an energy sink, whereby the state of the working medium is converted from the gaseous back into the liquid state.In a design known as a two-phase thermosiphon, the liquid working medium moves back to the first area by gravity, where it is heated again in the reaction chamber. In a design known as a heat pipe, in which, for example, a copper wire mesh is located inside the heat pipe, the return transport is driven by capillary forces. This cyclical process takes place within the heat pipe without moving any mechanical components. Therefore, a heat pipe is very wear-resistant and requires little maintenance. Furthermore, a heat pipe operates without vibration or shock.

[0032] In yet another embodiment, in addition to the heat-conducting connection of the hologram master to the at least one element of the cooling device, an inflow of cooling fluid and / or the use of at least one heat pipe is provided for cooling the hologram master. The at least one element can be, for example, a cooling register or a heat-conducting plate, for example made of a heat-conducting metal, which is in contact with a heat exchanger. For example, the hologram master can be integrated into a holder, which in turn is traversed by pipes through which a cooling fluid flows. The cooling fluid can be liquid or gaseous. In some

[0033] In some embodiments, the hologram master and / or other components of the reaction chamber to be cooled are arranged in a heat-conducting manner in contact with the at least one heat pipe and / or another or different element of the cooling device.

[0034] The cooling device preferably transfers the heat it has removed from the reaction chamber to an energy sink. This completely dissipates the thermal energy from the device. This prevents the device from heating up overall during hologram production.

[0035] In a preferred embodiment, the energy sink is a secondary fluid flow. This is, for example, a cooling circuit in which water is used as the secondary cooling fluid. Alternatively, the secondary cooling fluid can also be a cold gas. Alternatively, the energy sink can also be a material that changes its state of aggregation when heated, for example, dry ice or water-based ice.

[0036] However, the energy sink may also additionally or alternatively include or be a refrigeration machine.

[0037] It will be understood by those skilled in the art that during production, process steps b) to d) are carried out iteratively while process step e) is being carried out. This means that multiple holograms are produced while the reaction chamber is continuously cooled.

[0038] It has been shown that cooling to the normal temperature range of about 21°C or approximately 294 Kelvin represents a good compromise between high diffraction efficiency and energy consumption for cooling and the required insulation of the reaction chamber from the environment.

[0039] The invention is explained in more detail below with reference to a drawing. Herein: Fig. 1 a schematic representation of an apparatus for producing holograms using the contact copying process.

[0040] In Fig. 1 1 schematically shows a device 1 for producing holograms using the contact copying process. The device 1 comprises a plurality of chambers 10. In a feed chamber 11, holographic recording material 20 is provided on a supply roll 25. The holographic recording material 20 usually comprises a photopolymer layer 21. In addition, the holographic recording material 20 usually comprises a carrier layer 22, to which the photopolymer layer 21 is applied. Optionally, a protective layer 23 can be provided on the side of the photopolymer layer 21 facing away from the carrier layer 22. Both the carrier layer 22 and the protective layer 23 are transparent, i.e., imaging according to geometric optics is possible through them. This also means that no appreciable absorption and / or diffuse scattering takes place in the layers.

[0041] The holographic recording material 20 is guided through a reaction chamber 12, a UV fixing chamber 13, and a thermal fixing chamber 14 into a storage chamber 15, where the holographic recording material 20, after holograms have been exposed therein, is rolled up and held on a storage roll 35. The transport of the holographic recording material is accomplished by a transport device 30, which, for example, drives the storage roll 35 and, if necessary, additional transport rolls 31. The transport device 30 for feeding and removing the holographic recording material into and from the reaction chamber 12 can also be designed in any desired manner.

[0042] The individual chambers 10, in particular the feed chamber 11, the reaction chamber 12 and the UV fixing chamber 13, protect the holographic recording material from irradiation of light from outside the device 1. In addition, they protect the holographic recording material 20 and the devices located therein from other environmental influences, such as in particular dust and dirt.

[0043] In the reaction chamber 12, the holographic recording material 20 is arranged adjacent to a hologram master 40. Preferably, the hologram master 40 is a master volume reflection hologram 41.

[0044] To ensure good contact between the holographic recording material 20 and the hologram master 40, the holographic recording material 20 is brought into contact, for example, by means of a movable squeegee 50 with a bottom side 27 of the holographic recording material 20 and a top side 46 of the hologram master 40. For this purpose, the squeegee 50 is connected to a squeegee drive and guide device 51, which is only schematically indicated here.

[0045] In a laser chamber 16, coherent light 81 is generated in a coherent light source 60. Typically, the coherent light source 60 is a laser 61. The coherent light 81 enters an optics chamber 17 from the laser chamber 16. By means of beam-shaping and guiding optics 70, the coherent light 81 is expanded, shaped, and redirected and guided through the holographic recording material 20 onto the hologram master 40. The beam-shaping and guiding optics 70 are located in an optics chamber 17, which is formed above the reaction chamber 12 and the laser chamber 16. The coherent light 81 from the coherent light source 60, used for exposure, thus enters the reaction chamber 12 from the optics chamber 17. After the coherent light 81 has passed through the holographic recording material 20, it strikes the hologram master 40 and is at least partially reflected there.If the hologram master 40 is designed as a volume reflection hologram, the coherent light 81 is reflected as diffracted light 82. The coherent light can also be reflected on other hologram masters, for example if the hologram master is faceted, for example as a blaze grating or similar. The reflected, usually diffracted light 82 interferes in the holographic recording material 20 with the coherent light 81 irradiated for exposure. This causes local changes in the holographic recording material 20. If the holographic recording material 20 is designed as a photopolymer, chemical reactions are triggered that lead to changes in the refractive index in the photopolymer layer 21, i.e., the holographic recording material 20. The interference structure stored in this way is referred to as a hologram.The exposure of the hologram into the holographic recording material 20 can be carried out simultaneously in a planar or scanning manner, in that the coherent light 81 sweeps over the holographic recording material 20 and the hologram master 40 located thereunder, for example in a linear manner.

[0046] The beam-shaping and guiding optics 70 can optionally include a spatial light modulator 71 to spatially modulate the intensity of the coherent light 81 used for exposure. This ensures that, for example, in a master hologram representing a homogeneous luminous surface, such as a diffuser, this luminous surface is illuminated locally with varying "brightness" in the hologram. This allows for individualization of the hologram.

[0047] The hologram master can be configured to produce a single hologram or a plurality of holograms in a multiple-use process during an exposure process. In the illustrated embodiment, the holographic recording material 20 is not moved continuously, but rather stepwise through the various chambers 10 by means of the transport device 30. After a hologram has been exposed into the holographic recording material 20 in the reaction chamber 12, the holographic recording material 20 is first moved into the UV fixing chamber 13 and then into the thermal fixing chamber 14. In the UV fixing chamber 13, the holographic recording material is irradiated with ultraviolet radiation. In the thermal fixing chamber 14, the holographic recording material is heated, for example, via infrared radiation.In the two fixing chambers 13, 14, the holographic recording material loses its photosensitivity, while at the same time the hologram is permanently stored in the holographic recording material 20 in the form of refractive index changes. For other holographic recording materials, other post-processing steps for developing and / or fixing the hologram may be necessary and provided.

[0048] It has been found that the achievable diffraction efficiency in the holograms copied in this way can be increased if the reaction chamber 12 is cooled. A cooling device 100 is provided for this purpose. Fig. 1 A cooling device 100 is schematically illustrated, which combines different cooling devices and / or cooling variants. It will be understood by those skilled in the art that other embodiments may comprise only one and, if appropriate, alternatively designed cooling variant.

[0049] One cooling variant consists in flowing a cooling fluid 300 into the reaction chamber. Preferably, the cooling fluid 300 is a cooled gas or gas mixture. It is particularly preferably anhydrous. The fluid 300 is preferably flowed into the reaction chamber 12 by means of a fluid inflow device 110. The fluid inflow device 110 comprises, for example, one or more supply fans 111, which convey the cooling fluid 300 to an inflow opening 112. After the cooling fluid 300 has been heated in the reaction chamber 12, it preferably flows out of one or more outflow openings 113 in an upper region of the reaction chamber. The cooling fluid 300 can be taken from the environment of the device 1 or from a storage reservoir 310, for example, a compressed gas cylinder. In particular, if the cooling fluid 300 is taken from the environment, the cooling device can comprise a cleaning and filtering unit 116.Preferably, a drying unit 117 can additionally be provided, by means of which water contained in the fluid taken from the environment is removed and / or condensed. The cooling fluid 300 is preferably passed past a heat exchanger unit 115 and cooled relative to the environment. The cooling fluid 300 is preferably flowed into the reaction chamber 12 at the level of the hologram master 40 and / or the holographic recording material 20, so that the holographic recording material 20 and the hologram master 40 are cooled.

[0050] The heat exchanger unit 115 is preferably flowed through by a secondary cooling fluid 400 and absorbs the heat released by the cooling fluid 300 and transfers it to an energy sink 500. This can be a refrigeration machine or a cooling water circuit.

[0051] The illustrated embodiment of the cooling device 100 has, as a further cooling variant, a cooling register 120, which is thermally connected to the hologram master 40 directly or via a heat-conducting plate. The cooling register 120 is preferably flowed through by the secondary cooling fluid 400, which transfers the thermal energy absorbed by the hologram master to the energy sink 500.

[0052] In the illustrated embodiment, the cooling device 100 additionally comprises a heat pipe 130 as a cooling variant. Inside the heat pipe is a working medium which collects as a liquid in a lower region 137 of the heat pipe. Heat is absorbed via the outer wall of the heat pipe, which projects into the reaction chamber 12, and thus the interior of the reaction chamber 12 is cooled. The heat causes a phase transition in the working medium, so that it becomes gaseous and reaches the upper region 136 in the heat pipe. There, heat energy is released via the outer wall of the heat pipe, so that another phase transition takes place in the working medium, and in the liquid state it again reaches the lower region 137 of the heat pipe 130, driven by gravity or due to capillary forces.The heat in the upper region 136 of the heat pipe 130 can be dissipated to the ambient air, for example, by means of a cooling fan 140 of the cooling device 100. Alternatively or additionally, the heat pipe 130 can be cooled in the upper region by a cooling line 150 through which the secondary cooling fluid 400 flows.

[0053] It will be understood by those skilled in the art that the various variants with which the illustrated cooling device 100 is designed can be used in any combination to cool the reaction chamber 12. In particular, multiple inflow devices 110 and / or multiple heat pipes 130 and / or multiple cooling registers 120 can be provided. Furthermore, multiple cooling circuits for secondary cooling fluid can be provided. Furthermore, the cooling device can have multiple refrigeration machines as energy sinks and / or additionally or alternatively cooling water circuits.

[0054] Deviating from the illustrated embodiment, in which the secondary cooling fluid 400 flows directly through the cooling register 120, the cooling register 120 can comprise a closed primary cooling fluid circuit (shown in dashed lines) that transfers its heat to the secondary cooling fluid 400 via a further heat exchanger unit 125, which is coupled to an energy sink 500 in the form of a refrigeration machine and / or a cooling water line or the like. The secondary cooling fluid 400 can be directly connected to a cooling water line, so that the cooling water is the secondary cooling fluid 400. Typically, however, the secondary cooling fluid 400 circulates in a closed cooling circuit and is cooled in the refrigeration machine or by cooling water via a heat exchanger, in which the secondary cooling fluid 400 transfers its energy.

[0055] Deviating from the embodiment shown, instead of the heat pipe 130, one or more cooling registers through which the secondary cooling fluid 400 flows directly can be provided in the upper region of the reaction chamber. List of reference symbols

[0056] 1 Device for producing holograms 10 Chambers 11 Feed chamber 12 Reaction chamber 13 UV fixing chamber 14 Thermal fixing chamber 15 Storage chamber 16 Laser chamber 17 Optical chamber 20 Holographic recording material 21 Photopolymer 25 Supply roll 26 Top side 27 Bottom side 30 Transport device 35 Storage roll 40 Hologram master 41 Master volume reflection hologram 46 Top side 50 Squeegee 51 Squeegee drive and guide device 60 Coherent light source 61 Laser 70 Beam shaping and guiding optics 71 Spatial light modulator 81 Coherent light 82 Diffracted / reflected light 90 UV emitter 91 UV radiation 95 Infrared emitter 100 Cooling device 110Fluid inflow device 111Feed fan 112Inlet opening 113Outlet opening 115Heat exchanger unit 116Cleaning and filter unit 117Drying unit 120Cooling register 121Heat conducting plate 125Additional heat exchanger unit 130Heat pipe 136Upper section 137Lower section 140Cooling fan 150Cooling line 151Feed line152Discharge line 300Cooling fluid 310Storage tank 400Secondary cooling fluid 500Energy sink

Claims

1. Device (1) for producing holograms by the contact copying method, comprising a hologram master (40) a hologram master (40), a coherent light source (60) for generating coherent light (81), a transport device (30) for supplying and removing holographic recording material (20) so that it is arranged adjacent to the hologram master (40) for an exposure process, and a reaction chamber (12) which surrounds the hologram master (40) and protects the holographic recording material (20) from ambient light and foreign material during the exposure process, wherein the coherent light (81) of the coherent light source (60) is irradiated into the reaction chamber (12) during the exposure process, so that the coherent light (81) passes through the holographic recording material arranged adjacent to and in front of the hologram master (40) and is at least partially reflected back at the hologram master (40), so that changes are brought about inside the holographic recording material (20) due to interference between the coherent light (81) passing through the holographic recording material (20) and the light (82) at least partially reflected back from the hologram master (40). to form a hologram, or so that the hologram master (40) is transmitted so that a portion of the coherent light (81) passes through the hologram master (40) unchanged and a further portion of the coherent light (81) passes through the hologram master (40) unchanged of the coherent light is deflected at the holgram master (40), so that, due to interference between the one unchanged portion (81) of the coherent light and the further deflected portion of the coherent light (82), changes are brought about inside the holographic recording material (20) arranged adjacent to and behind the holgram master (40), which changes form the hologram forming the hologram, wherein a cooling device (100) for removing heat from the reaction chamber (12) is formed, characterized in that at least one element of the cooling device (100) is connected in a thermally conductive manner to the hologram master (40) in order to cool the hologram master (40).

2. Device (1) according to claim 1, characterized in that the cooling device (100) flows a cooling fluid into the reaction chamber (12).

3. Device (1) according to claim 1 or 2, characterized in that the cooling device (100) comprises at least one heat pipe (130).

4. Device (1) according to one of the preceding claims, characterized in that at least one component of the reaction chamber is arranged in contact in a thermally conductive manner with the at least one heat pipe and / or a further element of the cooling device in order to cool the reaction chamber.

5. Device (1) according to one of the preceding claims, characterized in that the cooling device (100) emits heat to an energy sink (500).

6. Device (1) according to claim 5, characterized in that the energy sink (500) comprises a secondary fluid flow and / or a refrigeration machine.

7. A method of producing holograms in the contact copying process comprising (a) providing a hologram master (40) in a reaction chamber (12) which surrounds and protects the hologram master (40) from ambient light and foreign material, (b) feeding holographic recording material (20) into a reaction chamber (12) surrounding the hologram master (40) so that the holographic recording material (20) is positioned adjacent to the hologram master (40) for an exposure process, (c) carrying out an exposure process by generating coherent light and irradiating it into the reaction chamber (12) so that the coherent light passes through the holographic recording material (20) arranged adjacent to and in front of the hologram master (40) and is at least partially reflected back at the master, so that changes which form a hologram are brought about inside the holographic recording material (20) due to interference between the coherent light passing through the holographic recording material and the light at least partially reflected by the hologram master (40), or so that the hologram master (40) is irradiated and a portion of the coherent light (81) passes the hologram master (40) unchanged light (81) passes the hologram master (40) unchanged and a further portion of the coherent light (82) is deflected at the hologram master (40), so that, due to interference between the one changed portion of the coherent light (81) and the further deflected portion of the coherent light (82), changes are brought about inside the holographic recording material (20) arranged adjacent to and behind the hologram master (40), which changes form the hologram, (d) discharging the holographic recording material (20) from the reaction chamber (12), wherein (e) heat is removed from the reaction chamber (12) by means of a cooling device (100), characterized in that at least one element of the cooling device (100) is connected in a thermally conductive manner to the hologram master (40) in order to cool the hologram master (40).

8. Method according to claim 7, characterized in that the method steps (b) to (d) are carried out iteratively while process step (e) is carried out.

9. Process according to claim 7 or 8, characterized in that the heat is dissipated from the reaction chamber (12) by means of the cooling device (100), which in turn dissipates heat to an energy sink (500).

10. Method according to one of claims 7 to 9, characterized in that the heat is dissipated from the reaction chamber (12) by means of a heat pipe (130) of the cooling device (100).