Application device, coating system, method for vapor deposition onto a film with metal vapor to form metal layers in a coating system, wound capacitor and use of a transfer roller

Abstract

An application device (18) for a coating system (10) for vapor deposition of metal vapor onto films to form a metal layer is specified, wherein the application device (18) has a vacuum chamber (34) and is configured to apply a masking fluid to the film to be subjected to vapor deposition in the vacuum chamber (34), wherein the application device (18) comprises a transfer roller (26) and a printing roller (28) which are arranged in the vacuum chamber (34), wherein a printing form (30) which is in contact with the transfer roller (26) is arranged on the printing roller (28). The application device (18) comprises an evaporator (32) for the masking fluid, which is configured to generate a masking fluid vapor. The application device (18) has a masking fluid vapor metering system (42) associated with the evaporator (32), which faces the transfer roller (26) and is configured to meter different amounts of masking fluid vapor transversely to the longitudinal axis of the transfer 15 roller (26) so that layers of masking fluid that have different local thicknesses are deposited on the transfer roller (26). Furthermore, the invention relates to a coating system (10), to a method for vapor deposition onto a film, to a wound capacitor and to the use of a transfer roller (26).

Description

APPLICATION DEVICE, COATING SYSTEM, METHOD FOR VAPOR DEPOSITION ONTO A FILM WITH METAL VAPOR TO FORM METAL LAYERS IN A COATING SYSTEM, WOUND CAPACITOR AND USE OF A TRANSFER ROLLER

[0001] The invention relates to an application device, in particular a web-fed rotary device, for a coating system for vapor deposition of metal vapor onto films to form a metal layer, as well as to a coating system comprising an application device and to a method for vapor deposition onto a film with metal vapor to form metal layers in a coating system. Furthermore, the invention relates to a wound capacitor which is formed by winding a coated film web. The invention also relates to the use of a transfer roller in a coating system.

[0002] Before a film is subjected to vapor deposition with metal vapor to form a metal layer, a masking fluid, such as oil, is applied to the film using the application device in the regions that are not intended to comprise a metal layer after the coating procedure. More specifically, no metal is to be deposited where the masking fluid is applied. Metal is deposited through condensation in the remaining regions. During the coating process, the masking fluid evaporates so that ideally no masking fluid remains on the film after the coating process is completed.

[0003] After the coating process, the films are further processed into electronic components, for example a wound capacitor, as mentioned at the outset.

[0004] The amount of masking fluid applied to the film must be metered with great precision. If the amount of masking fluid applied to a region is too small, metal deposits can form even in regions that are actually supposed to be free of metal. Such metal contamination can affect the quality of the electronic component made from the coated film. However, if too much masking fluid is applied, the masking fluid will not evaporate completely until the coating process is completed and the masking fluid residues that remain on the film can adversely affect downstream manufacturing processes. In particular, masking fluid can detach from the film inthe form of droplets and can distribute uncontrollably in the system or on the film. When these droplets strike a region of the film where a metal layer is to be formed, the droplets cause unwanted recesses in the metal layer, which in turn can affect the electronic component to be manufactured.

[0005] This is particularly challenging if the metal layer to be applied is intended to have regions of different thicknesses.

[0006] One object of the present invention is therefore to provide an application device for a coating system for vapor deposition of metal vapor onto films to form a metal layer, which application device is improved in terms of manufacturing quality, and a corresponding coating system. Furthermore, an object of the invention is to provide an improved method for vapor deposition onto a film with metal vapor to form metal layers in a coating system.

[0007] This object is achieved according to the invention by an application device, in particular a web-fed rotary printing device, for a coating system for vapor deposition of metal vapor onto films to form a metal layer. The application device has a vacuum chamber and is configured to apply a masking fluid, for example an oil, to the film to be subjected to vapor deposition in the vacuum chamber.

[0008] The application device comprises a transfer roller and a printing roller arranged in the vacuum chamber, wherein a printing form that is in contact with the transfer roller is arranged on the printing roller. Furthermore, the application device comprises an evaporator for the masking fluid, which is configured to generate a masking fluid vapor, wherein the application device has a masking fluid vapor metering system associated with the evaporator, which faces the transfer roller and is configured to meter different amounts of masking fluid vapor transversely to the longitudinal axis of the transfer roller so that layers of masking fluid that have different local thicknesses are deposited on the transfer roller.

[0009] The application device according to the invention has the advantage that the masking fluid applied to a film can be applied with different local thicknesses. In other words, the masking fluid print transferred from the printing roller to the film has regions with different layer thicknesses. This ensures that in the regions where increased metal condensation occurs and thicker metal layers are therefore formed, complete evaporation of the masking fluid does not occur before the end of the coating process, thus avoiding unwanted metal deposits. In the regions where less metal condensation occurs and the metal layer has a thinner layer thickness, no excessive masking fluid residue remains on the film. This prevents splashes of masking fluid from being removed from the film.

[0010] The masking fluid can be evaporated under vacuum and evaporates on the film due to its residual heat, wherein the evaporation process is supported by the vacuum in the vacuum chamber. In this respect, the masking fluid used has a boiling temperature that is adjusted to the conditions prevailing during the coating process with metal in order to ensure that the masking fluid evaporates on the film.

[0011] The masking fluid also has dielectric properties.

[0012] The viscosity of the masking fluid is selected such that the masking fluid does not run on the film, but can be easily transferred from the transfer roller to the printing roller and from there to the film.

[0013] For example, the masking fluid has a kinematic viscosity of 11 to 18 cSt at 40° and 2 to 4 cSt at 100°.

[0014] The printing form is, for example, replaceable, in particular configured as a sleeve that can be arranged on the main part of the printing roller. Thus, the application device can be used to represent different masking fluid prints on the film so that different transparent structures can be formed by the masking fluid, resulting in different metal structures.

[0015] According to one aspect, the metering process of the masking fluid vapor metering system is coordinated with the printing profile of the printing form. The printing profile corresponds to the desired masking fluid print on the film to be subjected to vapor deposition. Specifically, more masking fluid vapor is deposited in the regions that are transferred from the printing form to a region of the film where increased metal condensation is to take place.

[0016] For example, the printing profile has at least a first structure corresponding to a reinforced edge region of a film web and at least a second structure corresponding to an active region of a film web. The masking fluid vapor metering system is particularly adapted to the printing profile in such a way that more masking fluid vapor is metered in the region of the first structure than in the region of the second structure. In principle, the amount of masking fluid vapor that is absorbed can be adjusted via the structures of the printing profile.

[0017] The masking fluid vapor metering system may be a mask having at least one opening extending along the transfer roller, the width of which varies along the transfer roller, or the mask may have a plurality of openings, at least two of which openings have a different width. The width of the opening or the plurality of openings extends at least in a direction transverse to the longitudinal axis of the transfer roller or transverse to the longitudinal axis of the mask.

[0018] For example, the mask has a plurality of rectangular, circular, elliptical or other shaped openings. In the case of a circular or elliptical opening, the width corresponds to the diameter of the circle or, depending on the orientation of the ellipse, to the major or minor axis of the ellipse.

[0019] By varying the width of the continuous opening or the individual openings in the mask, the amount of masking fluid applied to the transfer roller is adjusted or controlled, i.e. , the amount of masking fluid metered can locally differ. The wider the opening, the more masking fluid can escape in thecorresponding region within a specific period of time and the thicker the layer of masking fluid that is deposited, in particular condenses, on the transfer roller. The metering process is therefore based on the opening geometry of the mask.

[0020] Overall, the amount of masking fluid to be metered can be controlled by the evaporation temperature of the masking fluid, i.e., the higher the temperature of the masking fluid, the more masking fluid escapes from the evaporator within a specific period of time. However, this does not allow the amount of masking fluid metered to locally differ. This is done as previously described by the masking fluid metering apparatus.

[0021] The mask may be a strip-shaped plate formed separately from the evaporator. Such a mask is particularly easy to produce, for example as a stamped part.

[0022] The mask is, for example, made of a metal, but other materials are also conceivable.

[0023] According to one aspect, the mask is detachably fastened, for example screwed, to an outlet opening in the evaporator. This makes it easy to replace the mask, for example when converting the coating system for a new production order. The masking fluid vapor metering system can thus be changed quickly and cost-effectively so that it is tailored to a different production order for the film to be subjected to vapor deposition, in particular to the associated printing form.

[0024] The masking fluid vapor is only intended to escape through the provided openings in the mask. To ensure this, a seal can be provided between the mask and the evaporator, for example in the form of a flat seal.

[0025] According to one embodiment, the opening in the mask has at least one cross-shaped cutout, from which connecting portions extend on both sides in the longitudinal direction of the opening, which connecting portions have a smallerwidth than the cross-shaped portion. For example, the width of the connecting portions is one quarter of the maximum width of the cross-shaped cutout. In this case, the opening is configured to run continuously along the mask.

[0026] Instead of a mask, it is conceivable for the masking fluid vapor metering system to comprise a plurality of nozzles arranged next to one another in the longitudinal direction of the transfer roller, each of which dispenses a different amount of masking fluid. In this way, the amount of masking fluid metered can also differ in the longitudinal direction of the transfer roller. The fluid flow flowing through each nozzle can be controlled, in particular individually for each of the nozzles, in order to meter different amounts of masking fluid vapor transversely to the longitudinal axis of the transfer roller, thus allowing the masking fluid vapor to be metered. For this purpose, the cross section of the fluid flow of the masking fluid vapor and / or a time average of the amount of masking fluid vapor can be controlled, for example with pulsed actuation of the nozzles.

[0027] A ceramic material may be provided on the outer surface of the transfer roller. In particular, a ceramic coating is applied to the circumferential surface of the transfer roller, for example to a core body, or a ceramic sleeve is arranged on a non-ceramic core body of the transfer roller. The ceramic outer surface allows for better adhesion and transfer of the masking fluid, which can reduce the temperature in the evaporator and thus the temperature of the masking fluid vapor. This has a positive effect on manufacturing quality. More specifically, the reduced temperature of the masking fluid reduces the thermal stress on the film, thereby preventing the film from wrinkling.

[0028] The ceramic material arranged on the outer surface of the transfer roller is ground, in particular on its surface. As a result, the surface of the transfer roller has, for example, a roughness Rz of 1 .0 to 1 .5 pm.

[0029] The outer surface of the transfer roller is in particular free of deliberately made structures, in particular depressions.

[0030] Due to the ceramic, in particular ground, surface, the transfer roller is able to absorb the required amount of masking fluid and transfer it to the printing roller. In other words, the absorption and release of masking fluid onto and from the transfer roller is particularly efficient.

[0031] Specifically, the ceramic surface of the transfer roller significantly reduces the absorption capacity of the transfer roller compared to previously known transfer rollers with a laser-cut surface, in particular by at least one third. This means that the transfer roller with a ground surface absorbs less masking fluid than, for example, a transfer roller with a laser-cut surface. In this respect, the surface of the transfer roller is a non-laser-cut surface, as it is a ground surface. For example, the masking fluid requirement is less than 1 cm3 / m2based on the surface area of the film web. Accordingly, the consumption of masking fluid can be significantly reduced by the transfer roller having the ceramic surface, which can save costs.

[0032] The transfer of the masking fluid to the printing roller is also particularly efficient by means of a transfer roller with a ceramic surface compared to using a transfer roller with a laser-cut surface. Laser-cut transfer rollers usually have depressions, for example in the form of honeycombs, truncated pyramids, diamonds, hashes and / or counter hashes, which hold the masking fluid.

[0033] In a transfer roller with a ceramic surface as described above, no such depressions are present, which means that a significantly lower contact pressure is required between the transfer roller and the printing roller, which has a beneficial effect on the service life of the transfer roller as well as the printing roller or a printing form arranged on the printing roller.

[0034] The absorption capacity of the transfer roller is also influenced by the rotational speed of the transfer roller. The rotational speed of the transfer rolleris, for example, between 20 and 50 revolutions per minute. In this case, the feed speed of the film web in the coating system is between 8 m / s and 14 m / s.

[0035] According to one aspect, the transfer roller and the printing roller are in contact with one another and a pressure prevailing between the transfer roller and the printing roller can be variably adjusted by means of at least one servo motor. This contributes to improving print quality as it allows the transfer of the masking fluid from the transfer roller to the printing roller to be adjusted.

[0036] The object is further achieved according to the invention by a coating system for vapor deposition of metal vapor onto films to form a metal layer, comprising an application device as described above, a conveyor apparatus for conveying a film web through the vacuum chamber and a vapor deposition apparatus for vapor deposition of metal vapor onto the film to form metal layers, which is arranged in the vacuum chamber.

[0037] In addition to the advantages already described in connection with the application device, the arrangement of the vapor deposition apparatus in the vacuum chamber allows the metal vapors to impinge on the film without air resistance, leading to a more uniform layer thickness. In particular, the film can be coated with a high degree of precision. In addition, the vacuum chamber forms a closed space, which prevents contamination of the film during the coating process.

[0038] The transfer roller, the printing roller and the evaporator can be removed from the vacuum chamber, in particular moved out, in order to change the mask and the printing form. For this purpose, the transfer roller, the printing roller and the evaporator can be arranged on a common carrier which is removable in order to be able to remove the transfer roller, the printing roller and the evaporator at the same time. The carrier can be movable.

[0039] The object is further achieved according to the invention by a method for vapor deposition onto a film with metal vapor to form metal layers in a coating system, for example in a coating system as described above.

[0040] In a first method step, a masking fluid is heated in an evaporator, whereby a masking fluid vapor which is deposited on a transfer roller is generated within a vacuum chamber while the transfer roller rotates, wherein an amount of masking fluid vapor metered differs along the longitudinal axis of the transfer roller so that layers of masking fluid that have different local thicknesses are deposited on the transfer roller. The different amounts of masking fluid vapor are metered along the longitudinal axis of the transfer roller, for example, by an application device according to the invention.

[0041] In a subsequent method step, the layer of masking fluid is first transferred from the transfer roller to a rotating printing roller that is in contact with the transfer roller, and, in the vacuum chamber, from the printing roller to a film web running through the vacuum chamber of the coating system in accordance with a printing pattern defined by a printing form provided on the printing roller, wherein at least a first region and a second region are formed on the film web in accordance with how much masking fluid is metered, wherein the layer of masking fluid is thinner in the first region than in the second region.

[0042] In each of the first region and the second region, at least one metal layer is applied by vapor deposition in the vacuum chamber, wherein the metal layer is thinner in the first region than in the second region.

[0043] The layer of masking fluid in one region has completely or almost completely evaporated at the point when the metal layer has been completely applied to the corresponding region. This is achieved in particular by ensuring that the masking fluid has a defined layer thickness in the corresponding region.

[0044] The metal applied by vapor deposition adheres only in places where there is no masking fluid, in particular no oil. In other words, the masking fluid represents a negative print on the subsequently applied metal layer. Since the layer of masking fluid evaporates continuously, in particular due to the condensation energy of the metal vapor applied and the irradiation energy of the vapor deposition apparatus, in order to avoid deposits in the region on which masking fluid is printed, a thicker layer of masking fluid is necessary in the regions where a thicker metal layer is to be applied and the coating process consequently takes longer. The residual heat of the masking fluid and the vacuum can also contribute to the evaporation of the masking fluid.

[0045] According to one aspect, the thickness of the layer of masking fluid is precisely matched to the thickness of the metal layer to be applied.

[0046] The first region and the second region extend in parallel with one another in the transport direction of the film web, for example.

[0047] For the purposes of the application, “almost completely evaporated” means that only small residues of the masking fluid may be present that they cannot cause splashes and thus do not have a detrimental effect on the downstream manufacturing steps.

[0048] The masking fluid vapor generated can escape through a mask associated with the outlet opening in the evaporator, in particular wherein, in the regions where the opening in the mask extending along the transfer roller has a greater width, a thicker layer of masking fluid is deposited on the transfer roller than in the regions where the opening in the mask has a smaller width. By means of a mask, the masking fluid can be metered along the transfer roller in a particularly simple manner. In particular, variable metering is carried out in a passive manner, i.e., without the need for complex control. Only the temperature of the masking fluid vapor set in the evaporator has an additional influence on the metering process.

[0049] According to one embodiment, the masking fluid is an oil, in particular a PFPE oil. Such an oil is particularly suitable as a masking fluid due to its vapor pressure and viscosity.

[0050] The first metal layer and the second metal layer can merge into one another. This creates an electrically conductive connection between the two metal layers.

[0051] In the second region, the metal layer can represent a reinforced edge region on a film web. In this case, this is also referred to as a heavy-edge region. Such a reinforced edge region serves to improve electrical properties. In particular, the metal layer in the reinforced edge region has a low degree of electrical resistance compared to the other regions of the metal layer, which reduces power loss and the temperature in the corresponding region, thus correspondingly extending the service life of the electronic component. The reinforced edge region is suitable, for example, for forming connection contacts, i.e., for creating an electrical connection.

[0052] In the first region, the metal layer can have fields separated from one another, each of which is connected to one another by a connecting piece. For example, the connecting piece is 0.1 mm to 1 mm wide. The masking fluid is applied in this region in the form of adjacent, unfilled contours, with each boundary line of a contour containing a continuous recess which later forms the connecting piece. The connecting piece serves as a fuse element or as a fuse, particularly in the form of a safety fuse, to minimize breakdown energy. This prevents the entire component from failing in the event of a fault.

[0053] The object is further achieved according to the invention by a wound capacitor which is formed by winding a film web that is coated as per a method according to the invention, wherein the metal layer in the first region forms an active region of the capacitor and the metal layer in the second region formsan electrical connection. Such a wound capacitor produced by the method according to the invention is characterized by particularly precisely represented electrical structures, wherein regions outside the electrical structures are (largely) free of unwanted metal deposits.

[0054] The object is further achieved according to the invention by the use of a transfer roller in a coating system, wherein the transfer roller has a ceramic surface which is ground to give the transfer roller a roughness Rz of 1.0 to 1 .5 pm. As already described above, such a transfer roller has an optimized absorption capacity.

[0055] The coating system in which the transfer roller is used comprises at least one application device which has a vacuum chamber and is configured to apply a masking fluid, for example an oil, to the film to be subjected to vapor deposition in the vacuum chamber. The application device also comprises an evaporator for the masking fluid, which is configured to generate a masking fluid vapor that is deposited on the transfer roller. The application device comprises a printing roller arranged in the vacuum chamber, wherein a printing form that is in contact with the transfer roller is arranged on the printing roller. The coating system also comprises a conveyor apparatus for conveying a film web through a vacuum chamber of the application device and a vapor deposition apparatus for vapor deposition of metal vapor onto the film to form metal layers, which apparatus is arranged in the vacuum chamber. In particular, the transfer roller is used in a coating system of the aforementioned type or in the application device of the aforementioned type.

[0056] Further advantages and features of the invention can be found in the following description and the accompanying drawings, to which reference is made. In the drawings:- Fig. 1 schematically shows a coating system according to the invention comprising an application device according to the invention,- Fig. 2 shows an evaporator for evaporating masking fluid,- Fig. 3 is a detailed view of the evaporator,- Fig. 4 shows a masking fluid metering system in the form of a mask,- Fig. 5 is a detailed view of an opening in the mask from Fig. 4,- Fig. 6 schematically shows a cutout of an alternative mask,- Fig. 7 shows an alternative evaporator comprising an integrated masking fluid metering system,- Fig. 8 is a cross section through a transfer roller,- Fig. 9 schematically shows a cross section of a film comprising a masking fluid,- Fig. 10 schematically shows a cross section of a film comprising a metal layer,- Fig. 11 shows a film comprising a metal layer, and- Fig. 12 schematically shows a sub-region of the film from Fig. 11.

[0057] Fig. 1 schematically shows a coating system 10 for vapor deposition of metal vapor onto films to form a metal layer.

[0058] The coating system 10 comprises a conveyor apparatus 12 for conveying a film web 14 through the coating system 10, a vapor deposition apparatus 16 for vapor deposition of metal vapor onto the films to form metal layers, and an application device 18, which in the embodiment is a web-fed rotary device, for example a flexographic printing press.

[0059] The conveyor apparatus 12 comprises an unwinding roller 20 and a winding roller 22 and conveyor and deflection rollers 24 arranged between the unwinding roller 20 and the winding roller 22 as well as a main cylinder 25 in the movement direction of the film web 14.

[0060] The application device 18 is configured to transfer a masking fluid onto the film web 14 and comprises a transfer roller 26 and a printing roller 28 on which a printing form 30 is arranged, said printing form being in contact with the transfer roller 26.

[0061] The pressure prevailing between the transfer roller 26 and the printing roller 28 can be variably adjusted by means of at least one servo motor 29. For example, two servo motors are provided for adjusting the pressure between the transfer roller 26 and the printing roller 28.

[0062] The pressure between the printing roller 28 and the main cylinder 25 can also be adjusted by means of one or more servo motors, which, however, are not shown for reasons of clarity.

[0063] In addition, the application device 18 comprises an evaporator 32 for the masking fluid, which is configured to generate a masking fluid vapor. For this purpose, the evaporator 32 comprises a heating apparatus (not shown in the drawings for the sake of simplicity).

[0064] The application device 18 also comprises a vacuum chamber 34.

[0065] The transfer roller 26, the printing roller 28 and the evaporator 32 are arranged in the vacuum chamber 34, in particular when the corresponding components are in an operating position. To convert the coating system 10, the transfer roller 26, the printing roller 28 and the evaporator 32 can be removed from the vacuum chamber 34, for example moved out.

[0066] The vapor deposition apparatus 16 of the coating system 10 is also arranged in the vacuum chamber 34 so as to be operated in a vacuum.

[0067] Furthermore, in the embodiment shown, the conveyor apparatus 12 is also arranged in the vacuum chamber 34, since the conveyor apparatus 12 conveys the film web 14 through the vacuum chamber 34. However, it is also conceivable that parts of the conveyor apparatus 12 are arranged outside the vacuum chamber 34.

[0068] In the embodiment in accordance with Fig. 1 , the vacuum chamber 34 is divided into two regions 36, 38 which are fluidically separated from one another, wherein the application device 18 and the vapor deposition apparatus 16 is arranged in the second region 38. By dividing the vacuum chamber 34 into two regions, the distribution of a metal vapor generated by the vapor deposition apparatus 16 is limited.

[0069] The conveyor apparatus 12 is largely arranged in the first region 36, wherein the main cylinder 25 of the conveyor apparatus 12 projects into the second region 38 in order to allow the metal vapor generated by the vapor deposition apparatus 16 to condense on the film web 14.

[0070] The regions 36, 38 are separated from one another, for example by a partition 40.

[0071] A masking fluid vapor metering system 42 is associated with the evaporator 32.

[0072] The masking fluid vapor metering system 42 faces the transfer roller 26 and is configured to meter different amounts of masking fluid vapor escaping from the evaporator 32 transversely to the longitudinal axis of the transfer roller 26 so that layers of masking fluid that have different local thicknesses are deposited on the transfer roller 26.

[0073] As a result, the masking fluid layer transferred from the printing roller 28 to the film web 14 has a varying thickness, which will be described in more detail below.

[0074] The metering process of the masking fluid vapor metering system 42 is coordinated with the printing profile of the printing form 30. This means that in the regions where the printing form 30 has a structure that requires a thickermasking fluid layer than other regions, more masking fluid vapor is metered by the masking fluid vapor metering system 42.

[0075] Fig. 2 shows an evaporator 32 by way of example, which is tubular in the embodiment.

[0076] The lateral pipe ends are sealed by end caps (not shown for simplicity).

[0077] A (continuous) outlet opening 44 extends along the longitudinal axis of the evaporator 32, via which the masking fluid vapor can escape.

[0078] The outlet opening 44 is surrounded by a circumferential contact surface 46 for the masking fluid vapor metering system 42, as can be seen in Fig. 3, which shows a sub-region of the contact surface 46.

[0079] The contact surface 46 is a flat surface, wherein a plurality of screw holes are provided within the contact surface 46 for fastening the masking fluid vapor metering system 42.

[0080] Fig. 4 and 5 illustrate a masking fluid vapor metering system 42 according to a first embodiment.

[0081] The masking fluid vapor metering system 42 illustrated in Fig. 4 is a mask 48 that can be detachably fastened to the evaporator 32, more specifically to the contact surface 46.

[0082] Specifically, in the embodiment according to Fig. 4 and 5, the mask 48 is a strip-shaped plate formed separately from the evaporator 32.

[0083] In the embodiment, the mask 48 can be screwed to the contact surface 46, but other ways of fastening it are also conceivable.

[0084] When the mask 48 is fastened to the evaporator 32, the mask is arranged at the outlet opening 44 in the evaporator 32 and partially covers it.

[0085] The mask 48 has an opening 50 which, when the evaporator 32, together with the mask 48, is mounted in the application device 18, extends along the transfer roller 26.

[0086] For example, a flat seal is provided between the mask 48 and the contact surface 46, which ensures that the masking fluid vapor leaves the evaporator 32 only in a specific manner, specifically via the opening 50.

[0087] The width of the opening 50 varies along the transfer roller 26, as can be seen particularly clearly in Fig. 5, which shows a recurring sub-portion of the opening 50.

[0088] The opening 50 illustrated in Fig. 5 has a plurality of cross-shaped portions 52. Connecting portions 53 extend on both sides starting from the cross-shaped portions 52. Thus, the width of the opening 50 varies between three different discrete values.

[0089] In an alternative embodiment (not shown for the sake of simplicity), rectangular portions may be present instead of cross-shaped portions. The width of the opening 50 would then vary between two discrete values.

[0090] Fig. 6 schematically illustrates a cutout of an alternative mask 48.

[0091] The mask 48 according to Fig. 6 differs from the mask 48 illustrated in Fig. 4 and 5 in that it does not comprise one continuous opening 50, but rather the mask 48 comprises a plurality of openings 54, 56 separated from one another, some of which differ in terms of their shape. In other words, discrete openings 54, 56 are provided, wherein at least two different sizes are provided.

[0092] Specifically, first rectangular openings 54 and second rectangular openings 56 are provided, which differ in terms of their width. Optionally, additional openings having a third width can be provided.

[0093] Instead of rectangular openings, circular, elliptical, hexagonal or other shaped openings may also be present.

[0094] Fig. 2 to 6 each illustrate an embodiment of the evaporator 32 or the mask 48 in which the mask 48 is formed separately from the evaporator 32 and is detachably fastened thereto.

[0095] Fig. 7 illustrates an alternative embodiment of the evaporator 32 in which the masking fluid vapor metering system 42, more specifically the mask 48, is integrally formed in the evaporator 32.

[0096] However, the embodiments according to Fig. 2 to 6 comprising a mask formed separately from the evaporator 32 have the advantage over the embodiment illustrated in Fig. 7 that when replacing the mask 48, the evaporator 32 itself does not have to be replaced, only the mask 48.

[0097] This may be necessary in particular if a different printing profile is desired on the film, which involves replacing the printing form 30. Typically, the printing form 30 and the masking fluid vapor metering system 42, in particular the mask 48, are coordinated with one another such that they are both changed to ensure that the masking fluid vapor is applied to the transfer roller 26 in the desired manner, with this therefore matching the printing profile of the printing form 30.

[0098] Fig. 8 shows a cross section through a transfer roller 26.

[0099] On the outer surface of the transfer roller 26 there is a ceramic material 58 which is applied, for example, to a core body 60 in the form of a ceramic coating or is pushed onto the core body 60 in the form of a sleeve.

[0100] The outer surface of the transfer roller 26 is free of laser engraving.

[0101] Instead, the ceramic outer surface of the transfer roller 26 is ground and has, for example, a roughness Rz of 1 .0 to 1 .5 pm.

[0102] The core body 60 is made from a non-ceramic material, for example steel.

[0103] With reference to Fig. 1 to 10, the following describes a method for vapor deposition onto a film with metal vapor to form metal layers in a coating system 10.

[0104] First, the masking fluid is heated in the evaporator 32, whereby a masking fluid vapor that escapes via the outlet opening 44 in the evaporator 32 and is deposited on the transfer roller 26 is generated within the vacuum chamber 34 while the transfer roller 26 rotates. As a result, the transfer roller 26 is circumferentially uniformly covered with masking fluid.

[0105] The amount of masking fluid vapor metered differs along the longitudinal axis of the transfer roller 26 so that layers of masking fluid that have different local thicknesses are deposited on the transfer roller 26. This process also takes place in the vacuum chamber 34, i.e. , under vacuum conditions.

[0106] In the embodiment, the mask 48 meters different amounts of masking fluid vapor, which mask is associated with the outlet opening 44 in the evaporator 32 and via which said vapor escapes.

[0107] More precisely, different amounts are metered due to the varying width of the opening 50. Where the opening 50 has a greater width, a greater amount of masking fluid vapor can escape from the evaporator 32 and condense on the transfer roller 26 during the same period of time, resulting in a greater masking fluid layer thickness on the transfer roller 26.

[0108] The same principle also applies to the mask 48 shown in Fig. 6, comprising a plurality of individual openings.

[0109] The masking fluid is, for example, a PFPE oil.

[0110] The layer of masking fluid is also first transferred from the transfer roller 26 to the rotating printing roller 28 in the vacuum chamber 34, which printing roller is in contact with the transfer roller 26, and from the printing roller 28, according to a printing pattern defined by the printing form 30 provided on the printing roller 28, to the film web 14 running through the vacuum chamber 34 of the coating system 10.

[0111] A schematic cross section of a cutout of a film web 14 to which a layer 62 of masking fluid is applied can be seen schematically in Fig. 9.

[0112] Depending on how much masking fluid is metered, at least a first region 64 and a second region 66 are formed on the film web 14, wherein the layer 62 of masking fluid is thinner in the first region 64 than in the second region 66.

[0113] The layer 62 does not necessarily have to be continuous, but can also have portions separated from one another and recesses, thus covering discrete regions. Specifically, the layer 62 represents a negative print of a subsequently applied metal layer, which will become clear from the following description.

[0114] The film portion of the film web 14 provided with the masking fluid is conveyed by the conveyor apparatus 12 from the application device 18, in particular from the printing roller 28, to the vapor deposition apparatus 16.

[0115] The vapor deposition apparatus 16 generates a metal vapor which is deposited on the film web 14 only in the regions where there is no masking fluid in order to form a metal layer there.

[0116] The metal vapor is, for example, a vapor made up of aluminum, zinc and silver, with aluminum and zinc being the main components of the vapor.

[0117] During the coating process, the masking fluid evaporates from the film web 14, in particular due to the condensation energy of the metal vapor applied and the irradiation energy of the vapor deposition apparatus. Since the layer 62 of masking fluid in the second region 66 takes longer to evaporate than in the first region 64 due to its greater layer thickness, vapor deposition of metal can take place in the second region 66 for a longer period of time and a thicker metal layer is consequently formed in the second region 66 than in the first region 64.

[0118] The amount of masking fluid metered and the corresponding layer thickness of the layer 62 on the film web 14 are selected such that the layer 62 of masking fluid in one region 64, 66 is completely or almost completely evaporated at the point when the metal layer in the corresponding region 64, 66 is completely applied.

[0119] Thus, after completion of the coating process, only a metal layer is present on the film web 14, but no masking fluid.

[0120] The amount of masking fluid deposited on the transfer roller 26 can be regulated, for example, by the evaporation temperature of the evaporator 32 and the rotational speed of the transfer roller 26. The higher the temperature in the evaporator 32, the greater the amount of masking fluid evaporated within a specific period of time. The slower the transfer roller 26 rotates, the more masking fluid can be deposited on the transfer roller.

[0121] Fig. 10 schematically illustrates a film web 14 after completion of the process of coating it with a metal layer, in particular a first metal layer 68 in the first region 64 and a second metal layer 70 in the second region 66.

[0122] The first metal layer 68 and the second metal layer 70 merge into one another in the embodiment.

[0123] In the second region 66, the metal layer 70 forms a reinforced edge region.

[0124] Fig. 11 shows a film web 14 provided with a metal layer 68, 70.

[0125] The coated film web 14 is usually centrally separated in exposed regions and centrally in the region of the second metal layer 70, i.e. , centrally in the so-called heavy-edge region.

[0126] Fig. 12 schematically shows an enlarged region of the metal layer 68 in the first region 64.

[0127] In the first region 64, the metal layer 68 has separate fields 72 which are separated from one another. In the embodiment, these are rectangular, in particular square. However, other structures are also conceivable, for example in the form of a parallelogram.

[0128] The fields 72 are each connected to one another by a connecting piece 74.

[0129] The connecting pieces 74 are, for example, 0.1 mm to 1 mm wide and form a fuse element or fuse to reduce breakdown energy.

[0130] The masking fluid is applied in this region in the form of adjacent, unfilled rectangles, wherein each boundary line contains a continuous recess which later forms the connecting piece 74. That is, as already explained above, the masking fluid forms a negative of the metal layer 68, 70.

[0131] A wound capacitor can be formed from the film web 14 shown in Fig. 11 by winding it up. The metal layer 68 in the first region 64 forms an active regionof the capacitor and the metal layer 70 in the second region 66 forms an electrical connection.

Claims

Claims1. An application device (18), in particular a web-fed rotary device, for a coating system (10) for vapor deposition of metal vapor onto films to form a metal layer (68, 70), wherein the application device (18) has a vacuum chamber (34) and is configured to apply a masking fluid, for example an oil, to the film to be subjected to vapor deposition in the vacuum chamber (34), wherein the application device (18) comprises a transfer roller (26) and a printing roller (28) which are arranged in the vacuum chamber (34), wherein a printing form (30) that is in contact with the transfer roller (26) is arranged on the printing roller (28), wherein the application device (18) comprises an evaporator (32) for the masking fluid, which is configured to generate a masking fluid vapor, and wherein the application device (18) has a masking fluid vapor metering system (42) associated with the evaporator (32), which faces the transfer roller (26) and is configured to meter different amounts of masking fluid vapor transversely to the longitudinal axis of the transfer roller (26) so that layers of masking fluid that have different local thicknesses are deposited on the transfer roller (26).

2. The application device (18) according to claim 1 , characterized in that the metering process of the masking fluid vapor metering system (42) is coordinated with the printing profile of the printing form (30).

3. The application device (18) according to either claim 1 or claim 2, characterized in that the masking fluid vapor metering system (42) is a mask (48) having at least one opening (50) extending along the transfer roller (26), the width of which varies along the transfer roller (26), or a plurality of openings (54, 56), at least two of which openings (54, 56) have a different width.

244. The application device (18) according to claim 3, characterized in that the mask (48) is a strip-shaped plate formed separately from the evaporator (32).

5. The application device (18) according to either claim 3 or claim 4, characterized in that the mask (48) is detachably fastened, for example screwed, to an outlet opening (44) in the evaporator (32).

6. The application device (18) according to any of the preceding claims, characterized in that a ceramic material (58) is provided on the outer surface of the transfer roller (26), wherein, in particular, a ceramic coating is applied to the circumferential surface of the transfer roller (26), for example to a core body (60), or a ceramic sleeve is arranged on a non-ceramic core body (60) of the transfer roller (26).

7. The application device (18) according to any one of the preceding claims, characterized in that the transfer roller (26) and the printing roller (28) are in contact with one another and a pressure prevailing between the transfer roller (26) and the printing roller (28) can be variably adjusted by means of at least one servo motor (29).

8. A coating system (10) for vapor deposition of metal vapor onto films to form a metal layer (68, 70), comprising an application device (18) according to any one of the preceding claims, a conveyor apparatus (12) for conveying a film web (14) through the vacuum chamber (34) and a vapor deposition apparatus (16) for vapor deposition of metal vapor onto the film to form metal layers (68, 70), which is arranged in the vacuum chamber (34).

9. A method for vapor deposition onto a film with metal vapor to form metal layers (68, 70) in a coating system (10), comprising the following steps:- heating a masking fluid in an evaporator (32), whereby a masking fluid vapor is generated which is deposited on a transfer roller (26) within a vacuum chamber (34) while the transfer roller (26) rotates, wherein an amount ofmasking fluid vapor metered differs along the longitudinal axis of the transfer roller (26) so that layers of masking fluid that have different local thicknesses are deposited on the transfer roller (26),- the layer of masking fluid is first transferred from the transfer roller (26) to a rotating printing roller (28) that is in contact with the transfer roller (26), and, in the vacuum chamber (34), from the printing roller (28) to a film web (14) running through the vacuum chamber (34) of the coating system in accordance with a printing pattern defined by a printing form (30) provided on the printing roller (28), wherein at least a first region (64) and a second region (66) are formed on the film web (14) in accordance with how much masking fluid is metered, wherein the layer of masking fluid is thinner in the first region (64) than in the second region (66),- at least one metal layer (68, 70) is applied by vapor deposition in the vacuum chamber (34) to the first region (64) and the second region (66), wherein the metal layer (68, 70) is thinner in the first region (64) than in the second region (66), and- wherein the layer of masking fluid in one region (64, 66) is completely or almost completely evaporated at the point when the metal layer (68, 70) is completely applied to the corresponding region.

10. The method according to claim 9, characterized in that the masking fluid vapor generated escapes through a mask (48) which is associated with an outlet opening (44) in the evaporator (32), in particular wherein, in the regions in which an opening (50) in the mask (48) extending along the transfer roller (26) has a greater width, a thicker layer of masking fluid deposited on the transfer roller (26) than in the regions in which the opening (50) in the mask (48) has a smaller width.

11. The method according to either claim 9 or claim 10, characterized in that the masking fluid is an oil, in particular a PFPE oil.

12. The method according to any of claims 9 to 11 , characterized in that the first metal layer (68, 70) and the second metal layer (68, 70) merge into one another.

13. The method according to any of claims 9 to 12, characterized in that, in the second region, the metal layer (70) represents a reinforced edge region on a film web (14).

14. The method according to any of claims 9 to 13, characterized in that the metal layer (68) in the first region has fields (72) which are separated from one another, each of which is connected to one another by a connecting piece (74).

15. A wound capacitor formed by winding a film web (14) coated according to claims 9 to 14, wherein the metal layer (68) in the first region (64) forms an active region of the capacitor and the metal layer (70) in the second region (66) forms an electrical connection.

16. A use of a transfer roller (26) in a coating system (10) for vapor deposition of metal vapor onto films to form a metal layer (68, 70), wherein the coating system (10) has an application device (18) which has a vacuum chamber (34) and is configured to apply a masking fluid, for example an oil, to the film to be subjected to vapor deposition in the vacuum chamber (34), wherein the application device (18) comprises an evaporator (32) for the masking fluid, which is configured to generate a masking fluid vapor that is deposited on the transfer roller (26), wherein the application device (18) comprises a printing roller (28) which is arranged in the vacuum chamber (34), wherein a printing form (30) that is in contact with the transfer roller (26) is arranged on the printing roller (28), and wherein the coating system (10) has a conveyor apparatus (12) for conveying a film web (14) through a vacuum chamber (34) of the application device (18) and a vapor deposition apparatus (16) which is provided for vapor deposition of metal vapor onto the film to form metal layers (68, 70) and is arranged in the vacuum27chamber (34), wherein the transfer roller (26) has a ceramic surface which is ground to give the transfer roller a roughness Rz of 1 .0 to 1 .5 pm.

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