Method for producing a thermally treated substrate with structured functional coating

Abstract

The invention relates to an improved method for producing a substrate (1), in particular a vehicle window, having a functional, in particularly electrically conductive, structured coating (2) on at least a partial region of a surface of the substrate (1), comprising the following steps: A) providing a substrate (1), B) creating the functional coating (2) in at least a partial region on a first surface of the substrate (1), C) structuring the functional coating (2) in at least one structuring region (3), D) applying a dielectric cover layer (5) at least to the structuring region (3) of the first surface of the substrate (1), E) thermally treating the coated substrate (1) from step D), in particular resulting in the shaping of the substrate (1), wherein the functional coating (2) in step C) is structured by mechanical removal. The invention also relates to a structured coated substrate (1) produced according to this method, and to the use of said substrate.

Description

[0001] Process for producing a thermally treated substrate with a structured functional coating

[0002] The invention relates to an improved method for producing a thermally treated substrate, in particular a vehicle window, with a structured functional coating, as well as a substrate produced thereafter with a structured functional coating and its use.

[0003] To meet both aerodynamic and stylistic requirements, many vehicle windows are curved. Vehicle windows also serve a variety of functions, such as window heating, antennas, sensors, etc.

[0004] For example, to provide an electric heater, thin electrically conductive layers are applied using known techniques such as screen printing or vapor deposition.

[0005] In the production of functional coatings, previous processes first apply the electrically conductive layer, for example, to a flat glass pane, and then structure it. It is known to strip electrically conductive coatings in certain areas using laser radiation. For example, the conductive coatings can be structured to direct a current flow, or they can be equipped with a so-called communication window that ensures the transmission of electromagnetic radiation. Examples of this are EP2591638B1, EP2335452B1, EP2586610B1, and WO2014033007A1.

[0006] DE 198 17 712 C1 describes a similar substrate with a communication window in a coating, which is created by applying a structuring in the form of fine lines or patterns in a limited area of ​​the coating and is visually very unobtrusive.

[0007] Document WO 00 / 72 635 A1 describes a transparent substrate with an IR-reflecting coating and a communication window created by removing or omitting the entire coating. In contrast to the communication windows discussed above, which are only applied in the form of fine lines, this variant creates a visually noticeable defect in the coating, among other things due to a color difference at the coating boundary. This defect is also problematic if the coating is also to be used for electrical heating of the substrate.

[0008] To bend a glass pane, it must be heated to relatively high temperatures, for example, 600°C. Since at these temperatures the electrically conductive layer would react with the surrounding atmosphere, the coating must be completely protected from bending by a removable protective layer, e.g., NaSCU. Such a protective layer is produced in a known manner by gassing the glass surface with sulfur dioxide (SO2). The SO2 reacts with the sodium (Na + ) and calcium (Ca 2+ ) on the glass surface to form sodium sulfate and calcium sulfate. However, this protection has been shown to be insufficient, so reactions still occur, especially in the edge area of ​​the structured functional coating.

[0009] Another problem is that, under the influence of heating, the pane and the functional coating are often heated to such an extent that flow processes occur, particularly in the edge area of ​​the structured functional coating. Furthermore, after bending, a protective layer must be completely removed, which is a laborious process.

[0010] Furthermore, the structured coatings, especially in their edge areas, can be exposed to corrosive processes, for example in laminated panes due to small amounts of water stored in the PVB interlayer.

[0011] The described influences can significantly impair the optical properties of the pane. For example, clearly perceptible optical disturbances and distortions can arise, particularly in the edge region of the functional coating. To solve these problems, EP 3515654 B1 proposes a device and a method for producing a structured functional coating, in which already thermally bent glass layers are coated and the coatings are structured using a laser. However, the equipment required for structuring a curved surface is very high, and the bonding of the individual panes to form a composite pane still takes place after the coating has been structured in a thermal process.

[0012] WO2022 / 248260A1 describes glazing with a metal-based coating and a protective layer on the edge.

[0013] US2023 / 280588A1 discloses a projection arrangement for a head-up display (HUD) with p-polarized radiation.

[0014] WO2022 / 223179A1 discloses a vehicle window with an IR-reflecting coating with a discontinuous metallic layer of metal nanocrystals.

[0015] EP2586610B1 discloses a disc with high frequency transmission.

[0016] WO2022 / 258402A1 discloses a pane with a patterned functional coating.

[0017] An object of the invention is therefore to provide an improved method that allows substrates subjected to a thermal treatment, in particular a thermal forming process, during the manufacturing process to be provided with a functional structured coating, in particular vehicle windows, with improved optical quality and appearance in a simple and cost-effective manner. This should be possible, in particular, without attacking the structured coating and / or without visually perceptible defects and distortions occurring in the resulting structured-coated substrate.

[0018] These and other objects are achieved by a method according to claim 1. Preferred embodiments are specified in the subclaims.

[0019] The invention relates to a method for producing a substrate, in particular a vehicle window, with a functional, in particular electrically conductive, structured coating on at least a partial area of ​​a surface of the substrate, comprising the steps

[0020] A) Providing a substrate, B) Creating the functional coating in at least one partial area on a first surface of the substrate,

[0021] C) Structuring the functional coating in at least one structuring area, or forming at least one structuring area,

[0022] D) applying a dielectric cover layer at least to the structuring area of ​​the first surface of the substrate,

[0023] E) Heat treatment of the coated substrate from step D), in particular by shaping the substrate, wherein the functional coating in step C) is structured by mechanical removal.

[0024] A dielectric cover layer is understood herein to be a layer, in particular a transparent layer, made of dielectric material that is applied to at least the structured surface portion, i.e., the structuring region, of the functional coating on the substrate surface prior to heat treatment, in particular thermal forming, for example, thermal prestressing or a bending process step, and remains there. In contrast to the previously known use of a protective layer, which is only temporarily applied to the coated substrate surface and subsequently removed again, the invention thus forms a permanent covering of the structuring region of the coating on the substrate surface. In this surface region of the substrate, the dielectric cover layer initially forms a layer directed towards the atmosphere / environment.

[0025] Due to the inhomogeneity or discontinuity of the functional coating caused by the structuring, optical distortions and degradation of the coating occur during heat treatment, and in particular heat treatment in conjunction with a forming process, such as a bending process. These are primarily due to the different mechanical and thermal behavior of the coated and uncoated areas (e.g., the bare glass surface) of the substrate, for example, a structured-coated glass pane. According to the invention, it is possible to homogenize these structuring areas to a certain extent by at least locally applying the dielectric cover layer, thus preventing or at least significantly reducing the optical disturbances that previously occurred.

[0026] By applying such a dielectric cover layer according to the invention at least to the structuring region of the functional coating on the substrate surface, the optical quality and appearance of the structured-coated and subsequently thermally treated, in particular shaped, substrate can surprisingly be significantly improved. Firstly, flow processes during heating and any shaping in the heated state, which occur in particular at the edges of the structured coating, can be effectively contained or even completely prevented. Furthermore, corrosive reactions and processes of the structured coating, for example with the atmosphere, remaining residues of any protective layer, or embedded water molecules in surrounding hygroscopic layers, are also permanently avoided or at least reduced in the long term by the dielectric cover layer.Visually perceptible defects or distortions of the coated substrate, especially in the structuring area of ​​the functional coating, are avoided or at least significantly reduced. The optical appearance can thus be significantly improved.

[0027] According to one embodiment, the substrates are, in particular, single panes, such as single-pane safety glass, and / or panes for the production of composite panes for vehicles. Such vehicle panes consisting of one, two, or more glass or polymer panes are used in particular in motor vehicles, for example as windshields, roof windows, rear windows, and / or side windows.

[0028] Functional coatings are preferably metal-based, particularly electrically conductive, coatings. One or more of these functional coatings can be applied to individual sides, i.e., pane surfaces. Especially in the area of ​​vehicle windows, functional coatings with infrared-reflecting properties, anti-reflective properties, low-E properties, and / or those that can be electrically heated by applying a voltage, or even active coatings such as electrochromic or photovoltaic coatings, are known. The functional coating is preferably transparent.

[0029] The functional coating can extend over the entire surface of the substrate, for example, a (glass) pane, and be applied essentially over the entire surface. Alternatively, however, the functional coating can also extend only over a limited portion of the surface of a substrate, for example, on one surface side of a first pane. The functional coating can, for example, extend over at least 50%, particularly preferably over at least 70%, for example over at least 90%, of a surface of the first pane.

[0030] According to the invention, the functional coating is structured in step C) by mechanical removal. According to the invention, stripping by laser ablation is particularly preferred. This has the particular advantage of being cost-effective, fast, and precise. Due to its precision, laser ablation is also particularly suitable for narrow widths, for example, in the case of a planned linear stripping.

[0031] According to a preferred embodiment, in step C), the structuring takes place in the form of a pattern comprising at least one line. In one embodiment, the at least one line has a line width in a range from 0.05 mm to 0.5 mm. The pattern preferably comprises a plurality of lines. According to one embodiment, the lines of the plurality of lines are introduced into the functional coating such that they are arranged either parallel or perpendicular to one another.

[0032] According to the invention, structured coatings or structuring areas of functional coatings can have or form a wide variety of functions and fulfill tasks, such as antennas, communication windows that are permeable to high-frequency radiation, or serve to form capacitors, resistors, electrical insulation, touch switches (touch control) or control panels, etc.In a preferred embodiment of the method, in step D) the dielectric cover layer is applied by a chemical vapor deposition process, preferably by atomic layer deposition (ALD), flame-assisted chemical vapor deposition (FA-CVD) or by atmospheric pressure chemical vapor deposition (APCVD), particularly preferably by flame-assisted chemical vapor deposition (FA-CVD) or by atmospheric pressure chemical vapor deposition (APCVD).

[0033] The aforementioned deposition processes, FA-CVD and APCVD, which are particularly preferred for applying the dielectric top layer, are proven, cost-effective, and robust methods for producing thin coatings. The requirements and equipment expenditure are also lower than, for example, with plasma-enhanced chemical vapor deposition (PECVD). Like PECVD, APCVD (atmospheric pressure chemical vapor deposition) is a form of chemical vapor deposition, but it takes place at atmospheric pressure rather than under vacuum. This is advantageously more energy- and time-efficient because it eliminates the need to evacuate the process chambers, and the reaction gases can be flowed directly onto the substrate, which is not possible in a vacuum.Furthermore, the APCVD method is an inline process, meaning that even continuous flow of substrates to be coated is possible, whereas PECVD systems or diffusion furnaces are usually used in batch processes. Atomic layer deposition (ALD) is particularly advantageous for depositing very thin layers over large areas.

[0034] In a preferred embodiment of the method, the dielectric cover layer is applied to the surface of the substrate as a transparent single layer, preferably with a layer thickness of up to 1 pm, preferably with a layer thickness of 10 nm to 900 nm, for example with a layer thickness between 30 nm and 700 nm. For example, the dielectric cover layer can be formed with a layer thickness of 10 nm, up to 150 nm, up to 200 nm, up to 300 nm, or up to 400 nm. The resulting layer thickness for the dielectric cover layer can advantageously be adjusted accordingly to the application and the required properties.

[0035] The dielectric cover layer can, for example, comprise at least one of silicon oxide (SiO2), silicon nitride (SiO2), zinc oxide, tin-zinc oxide, silicon-metal mixed nitrides, such as silicon zirconium nitride, zirconium oxide, niobium oxide, hafnium oxide, tantalum oxide, tungsten oxide, and silicon carbide. The oxides and nitrides mentioned can be deposited stoichiometrically, substoichiometrically, or superstoichiometrically. They can contain dopants, for example, aluminum, zirconium, titanium, or boron. The dielectric cover layer particularly preferably comprises silicon oxide (SiO2), since this is almost invisible, i.e., barely perceptible to an observer, particularly in combination with glass and PVB. The dielectric cover layer particularly preferably comprises at least 90 wt.% silicon oxide (SiO2), more preferably at least 95 wt.% silicon oxide (SiO2), in particular at least 99 wt.% silicon oxide (SiO2).

[0036] According to one embodiment, the dielectric cover layer represents the final layer of the substrate. A further layer on the dielectric cover layer is not necessary to protect the patterning region and would incur additional costs.

[0037] In a preferred embodiment, the refractive index of the applied cover layer at a wavelength of 550 nm is between 1.4 and 1.6, particularly preferably between 1.45 and 1.55, for example 1.51. In the context of the present invention, refractive indices are generally specified based on a wavelength of 550 nm. The refractive index is fundamentally independent of the measurement method. It can be determined, for example, by means of ellipsometry. Ellipsometers are commercially available. When determining the refractive indices, the same measurement method is used for the specified components, for example of a composite pane produced according to the invention.

[0038] In a composite pane produced according to the invention, i.e. a composite pane in which at least one pane (inner pane and / or outer pane, for example made of glass) corresponds to the substrate according to the invention, i.e. this at least one pane has a structured coating and is provided with a dielectric cover layer at least in the formed structuring region, the refractive index of the inner pane, outer pane and the thermoplastic intermediate layer (for example made of PVB), the functional coating and the dielectric cover layer is particularly preferably the same or almost the same. This then results in a particularly uniform appearance of the composite pane. The transitions between the different materials are therefore barely perceptible to the human eye. The refractive index can therefore be between 1.4 and 1.6, for example 1.51, for all components of the formed composite pane at a wavelength of 550 nm.

[0039] In preferred embodiments of the process according to the invention, the functional coating in step B) is applied by physical vapor deposition (PVD) or chemical vapor deposition (CVD), in particular by physical vapor deposition. Sputtering, in particular magnetic field-assisted sputtering (magnetron sputtering), has proven particularly suitable for producing thin films on glass substrates. However, other types of physical vapor deposition can also be used, for example, thermal evaporation (evaporation), electron beam evaporation, laser beam evaporation, arc evaporation, or molecular beam epitaxy. Preferred CVD processes are plasma-enhanced chemical vapor deposition (PECVD) and atomic layer deposition (ALD).

[0040] In addition to at least one structuring region, the functional coating can also have one or more uncoated or decoated planar zones. Such planar, coating-free zones can, for example, be permeable to electromagnetic radiation and can also be used, for example, as data transmission windows or communication windows. According to the invention, such zones can also be provided with a dielectric cover layer, which protects, in particular, the edge regions of the functional coating from degradation during heat treatment of the substrate, especially during a thermally assisted forming process step, such as a tempering and / or bending process, for example, in automotive glass production.Optical distortions or defects due to discontinuities in the coating caused by flow processes or degradation in the edge region of the coating can be effectively prevented or at least significantly reduced by the dielectric cover layer provided according to the invention. The optical quality and appearance of the structured-coated substrate can thus be significantly improved compared to the prior art.

[0041] Functional, in particular electrically conductive, coatings according to the invention are known, for example, from DE 20 2008 017 611 U1, EP 0 847 965 B1 or WO 2012 / 052315 A1. They typically contain one or more, for example two, three or four, electrically conductive, functional layers. The functional layers preferably contain at least one metal, for example silver, gold, copper, nickel and / or chromium, or a metal alloy. The functional layers particularly preferably contain at least 90 wt. % of the metal, in particular at least 99.9 wt. % of the metal. The functional layers can consist of the metal or the metal alloy. The functional layers particularly preferably contain silver or a silver-containing alloy. In other words, in a particularly preferred embodiment of the method according to the invention, the functional coating produced in step B) is based on silver (Ag).Such functional layers exhibit particularly advantageous electrical conductivity combined with high transmission in the visible spectral range.

[0042] Further examples of suitable functional coatings preferably include indium tin oxide (ITO), fluorine-doped tin oxide (SnO2:F), or aluminum-doped zinc oxide (ZnO:Al). This list of possible suitable functional coatings is merely exemplary and not exhaustive.

[0043] In a preferred embodiment, the functional coating has a layer thickness of 50 nm to 1000 nm, particularly preferably of 100 nm to 450 nm.

[0044] Other known coatings can also be applied beneath the actual functional coating, such as adhesion promoter layers to improve the adhesion of the functional coating to the substrate, adjustment or smoothing layers to influence the morphology of the functional coating, or blocker layers, for example, to prevent alkali diffusion from a glass substrate into the functional coating. If decoating is used to structure the functional coating, such additional layers are also removed.

[0045] A preferred embodiment of the method further provides that it comprises the steps

[0046] F) Providing a second substrate, which optionally undergoes steps B) to E), and a thermoplastic composite film,

[0047] G) forming a stacking sequence of the first substrate, a thermoplastic composite film and the second substrate, and

[0048] H) joining the stacking sequence from step G) under the influence of heat, pressure and / or vacuum to form a composite pane.

[0049] The substrate provided in step A) is also referred to as the "first substrate." The first and second substrates are preferably glass panes, which are particularly preferably provided as components of a composite pane of a means of locomotion on land, water, or in the air, which is in particular a windshield, roof pane, side window, or rear window of a vehicle, preferably the windshield of a motor vehicle. The two glass panes of the composite pane are preferably bent simultaneously in pairs. Vehicle panes with flat areas can offer advantages in terms of flow resistance and are preferred for aerodynamic reasons. This applies particularly to windshields and roof panes.

[0050] The first and / or second substrates, preferably the first pane and / or the second pane, preferably contain glass, particularly preferably float glass, quartz glass, borosilicate glass, soda-lime glass, or clear plastics, preferably rigid clear plastics, in particular polyethylene, polypropylene, polycarbonate, polymethyl methacrylate, polystyrene, polyamide, polyester, polyvinyl chloride, and / or mixtures thereof. The first substrate and / or the second substrate are preferably transparent, particularly for the preferred use as a windshield, side window, or rear window of a vehicle or other uses where high light transmission is required or desired.

[0051] "Transparent" within the meaning of the invention refers to a part, in particular a substrate, preferably a pane, film, or coating or cover layer, that has a transmission in the visible spectral range of greater than 70%. However, for panes or pane areas that are not within the driver's traffic-relevant field of vision, such as roof windows, the transmission can also be much lower, for example, greater than 5%.

[0052] The thickness of the individual panes can vary widely and thus be perfectly adapted to the requirements of the individual case. Panes with standard thicknesses of 0.5 mm to 25 mm, preferably 1.4 mm to 2.5 mm, for example 1.6 mm or 2.1 mm, are preferred for automotive glass, which is preferably used in laminated safety glass (LSG).

[0053] Toughened safety glass (ESG) is also used for side and rear windows and roof glazing. The safety principle of toughened safety glass lies in its special fracture pattern. In the event of damage, it shatters into a multitude of small, blunt-edged pieces of glass. High-quality float glass in standard thicknesses of 3.4 mm or 5 mm (clear or tinted) is used for this type of toughened safety glass.

[0054] The panes used as substrates in the process can have any three-dimensional shape. The three-dimensional shape preferably has no shadow zones, so that it can be easily coated with the functional coating, for example, by cathode sputtering. The panes are therefore preferably initially planar and, after the formation of the structured coating and the application of the dielectric cover layer, are bent slightly or strongly in one or more directions of space in a thermal forming process, in particular a bending process, as is common for vehicle windows. Typical radii of curvature range from approximately 10 cm to approximately 40 m. The panes can be colorless or colored.

[0055] During process steps F), G) and H), the panes are bonded together to form a composite pane by at least one intermediate layer. The intermediate layer is formed by at least one thermoplastic composite film and preferably contains at least one thermoplastic, preferably polyvinyl butyral (PVB), ethylene vinyl acetate (EVA) and / or polyethylene terephthalate (PET). However, the thermoplastic composite film can also contain, for example, polyurethane (PU), polypropylene (PP), polyacrylate (PA), polyethylene (PE), polycarbonate (PC), polymethyl methacrylate, polyvinyl chloride, polyacetate resin, casting resin, acrylate, fluorinated ethylene propylene, polyvinyl fluoride and / or ethylene tetrafluoroethylene or copolymers or mixtures thereof. Typical layer thicknesses for commercially available PVB films are, for example, 0.76 mm or 1.14 mm, although this is not limiting for the invention.

[0056] In a further preferred embodiment, the first substrate and the second substrate, for example an inner and an outer pane for a vehicle composite pane, are jointly subjected to a heat treatment and jointly formed in step E). The outer pane and the inner pane are therefore preferably subjected to a bending process before lamination. Preferably, the outer pane and the inner pane are congruently bent together, i.e. simultaneously and using the same tool, because this ensures that the shape of the panes is optimally coordinated for the lamination that takes place later in step H). Typical temperatures for glass bending processes, such as continuous, gravity, press bending, or vertical bending methods, are, for example, 500°C to 700°C.

[0057] Further preferred embodiments of the process according to the invention provide that both substrates are coated with an identical or different functional coating in step B).

[0058] In step C), a functional coating on the first substrate and second substrate can be structured identically or differently, as long as the functional coating of at least the first substrate is structured by mechanical ablation. On the one hand, this can mean that the same or a different method is used for structuring. For example, the structuring of the coating of both substrates can be carried out by laser ablation. Alternatively, for example, the structuring region of the first substrate can be created by laser ablation, while the coating of the second substrate is structured, for example, by milling. On the other hand, the structuring of the coatings of both substrates can be identical or different, for example in regular or irregular patterns, linear, as parallel and / or grid-like intersecting lines, or as a dot matrix.In step D), the patterned regions formed on the first substrate and the second substrate can be provided with an identical or different dielectric cover layer. Thus, the dielectric cover layers can each be formed, for example, from the same dielectric material and with the same layer thickness using the same method. It is also possible to select different dielectric materials or, with the same material, to form the dielectric cover layer with a different layer thickness.

[0059] The invention further comprises a substrate, in particular a vehicle window, with a functional coating, produced by a method as described above in various embodiments, wherein the functional coating is formed in at least one partial region on at least one surface of the substrate and has at least one structuring region, and a dielectric cover layer is applied at least to this structuring region. The dielectric cover layer thus covers at least the surface area in which the functional coating is structured and thus covers, in particular, the coating-free regions of the substrate surface resulting from the structuring.The functionality of the functional coating is advantageously not negatively affected by the application of the dielectric cover layer, whereas the edge areas to the coating-free areas of the structuring are very well protected against degradation. Furthermore, the dielectric cover layer ensures that, when the substrate and / or the structured coating soften during heat treatment and any molding process, flow processes are largely contained or prevented. This can significantly improve the optical quality of the substrate with the structured coating. Visually perceptible defects or distortions can be avoided or at least significantly reduced. As already described above for the process, the "structuring area" is understood to be the structured surface portion of the functional coating.

[0060] According to one embodiment, the functional coating in the structuring region has a pattern comprising at least one line. In one embodiment, the at least one line has a line width in a range from 0.05 mm to 0.5 mm. The pattern preferably comprises a plurality of lines. According to one embodiment, the lines of the plurality of lines are incorporated into the functional coating such that they are arranged either parallel or perpendicular to one another.

[0061] The dielectric cover layer is preferably a single layer made of a dielectric material, which comprises, for example, at least one of silicon oxide (SiO2), silicon nitride (SiO4), zinc oxide, tin-zinc oxide, silicon-metal mixed nitrides, such as silicon zirconium nitride, zirconium oxide, niobium oxide, hafnium oxide, tantalum oxide, tungsten oxide and silicon carbide. The dielectric cover layer preferably comprises SiO2 and / or SiO2. The aforementioned oxides and nitrides can be deposited stoichiometrically, substoichiometrically or superstoichiometrically. They can have dopants, for example aluminum, zirconium, titanium or boron. The dielectric cover layer is particularly preferably a single layer comprising SiO2, since such a dielectric cover layer is almost invisible, i.e. barely perceptible to an observer, particularly in combination with glass and PVB. The dielectric cover layer particularly preferably comprises at least 90 wt.% silicon oxide (SiO2), more preferably at least 95 wt. % silicon oxide (SiO2), in particular at least 99 wt. % silicon oxide (SiO2).

[0062] In a preferred embodiment, the dielectric cover layer has a layer thickness of up to 1 pm, preferably a layer thickness of 10 nm to 900 nm. For example, the layer thickness of the dielectric cover layer can be 10 nm, up to 150 nm, up to 200 nm, up to 300 nm, or up to 400 nm. The layer thickness formed for the dielectric cover layer can advantageously be adjusted accordingly to the application and the required properties. In particular, the dielectric cover layer is transparent.

[0063] In a preferred embodiment of the structured coated substrate, the functional coating has a layer thickness of 50 nm to 1000 nm, particularly preferably of 100 nm to 450 nm.

[0064] According to one embodiment, the dielectric cover layer represents the final layer of the substrate. A further layer on the dielectric cover layer is not necessary to protect the structuring region of the functional coating and would incur additional costs. The invention further encompasses the use of a substrate, as described above in various embodiments, for producing a pane of a means of transport on land, water, or in the air, preferably a vehicle pane, in particular a windshield, roof pane, side window, or rear window, or a pane for a building, preferably a window pane, facade pane, or door pane.

[0065] The various embodiments of the invention can be implemented individually or in any combination. In particular, the features mentioned above and explained below can be used not only in the specified combinations, but also in other combinations or on their own, unless they are explicitly described and described as alternatives to one another without departing from the scope of the present invention. This also applies to features mentioned only for the substrate or only for the method.

[0066] The invention is explained in more detail below using exemplary embodiments, with reference to the accompanying figures. They show, in a highly simplified, schematic representation, not to scale:

[0067] Figures 1a to 1e schematically show steps A) to E) according to an embodiment of the method according to the invention, wherein in each case a cross-sectional view is shown in the enlarged section V (see Figure 2a);

[0068] Figure 2a shows a plan view of a substrate coated with a structure according to the invention;

[0069] Figures 2b and 2c show simplified, schematic transverse views of the bent substrate;

[0070] Figure 3 shows schematically a composite pane in enlarged section V, which was manufactured by steps A) to H) according to an embodiment of the method according to the invention.

[0071] Figure 4 shows a plan view of a substrate coated according to the invention in the form of a trapezoidal, curved windshield. Figures 5 and 5a show a cross-sectional view of an example according to the prior art without a dielectric cover layer.

[0072] Figures 1a to 1e schematically show steps A) to E) in an embodiment of the method according to the invention, wherein a cross-sectional view is shown in the enlarged section V (see Figure 2a). The method for producing a substrate 1, in particular a vehicle window, with a functional, in particular electrically conductive, structured coating 2 on at least a partial area of ​​a surface of the substrate 1, comprises the steps

[0073] A) Providing a substrate 1 ,

[0074] B) producing the functional coating 2 in at least one partial area on a first surface of the substrate 1,

[0075] C) Structuring the functional coating 2 in at least one structuring area 3 or forming at least one structuring area 3,

[0076] D) applying a dielectric cover layer 5 at least to the structuring region 3 of the first surface of the substrate 1,

[0077] E) Heat treatment of the coated substrate 1 from step D), in particular by shaping the substrate 1, wherein the functional coating 2 is structured in step C) by mechanical removal.

[0078] The substrate 1 provided in step A) is particularly preferably a glass pane, which is particularly preferably intended as a vehicle window or a component of a laminated pane. Thus, the substrate 1 can be, for example, a single-pane safety glass (ESG) or a laminated safety glass (VSG).

[0079] The functional coating produced in step B) is preferably a metal-based, particularly electrically conductive, coating and can fulfill a wide variety of functions. Especially in the automotive sector, functional coatings with infrared-reflecting properties, anti-reflective properties, low-E properties, and / or those that can be electrically heated by applying a voltage are already being used, as are active coatings such as electrochromic or photovoltaic coatings. The functional coating is preferably transparent. The production of such a functional coating is preferably carried out using known and established methods, such as physical or chemical vapor deposition processes.

[0080] The functional coating 2 is structured in step C) by mechanical removal. Laser ablation is preferred for mechanical removal. This has the particular advantage of being cost-effective, fast, and precise. Due to its precision, laser ablation is also particularly suitable for narrow widths, for example, in the case of linear decoating.

[0081] According to the invention, structured coatings or structuring regions 3 of functional coatings 2 can have or form a wide variety of functions and fulfill tasks, such as antennas, communication windows that are permeable to high-frequency radiation, or serve to form capacitors, resistors, electrical insulation, touch switches (touch control) or control panels, etc.

[0082] The dielectric cover layer 5 can be applied in step D) by a chemical vapor deposition process, preferably by atomic layer deposition (ALD), flame-assisted chemical vapor deposition (FA-CVD), or atmospheric pressure chemical vapor deposition (APCVD), particularly preferably by flame-assisted chemical vapor deposition (FA-CVD) or atmospheric pressure chemical vapor deposition (APCVD). The FA-CVD and APCVD deposition processes are proven, inexpensive, and robust methods for producing thin coatings. The requirements and equipment expenditure are also lower than, for example, with PECVD.APCVD (atmospheric pressure chemical vapor deposition), like PECVD, is a form of chemical vapor deposition, but it takes place at atmospheric pressure rather than under vacuum. This is advantageously more energy and time efficient, as evacuation of the process chambers is not necessary and the reaction gases can be flowed directly onto the substrate, which is not possible in a vacuum. Atomic layer deposition (ALD) is particularly advantageous for depositing very thin layers over large areas.

[0083] In step E), the substrate 1, for example a pane for producing toughened safety glass, is heated to approximately 600°C in a tempering bending process and bent into the appropriate shape. This can typically be done using a continuous, gravity, press bending, or vertical bending process. The glass pane is then suddenly cooled by blowing high-pressure air onto the glass surface via individual nozzles. This places the surfaces of the pane under compressive stress, and the center of the glass under tensile stress. Compared to normal glass, the toughened safety glass therefore has greater resistance to mechanical and thermal stress. Advantageously, the optical appearance of such a substrate 1 with an applied structured coating 2 can be significantly improved by the dielectric cover layer 5 provided according to the invention, at least on the structuring region 3.

[0084] The functionality of the functional coating 2 is advantageously not negatively affected by the application of the dielectric cover layer 5, whereas the edge regions 6 to the coating-free regions 4 of the structuring are very well protected against degradation. Furthermore, the dielectric cover layer 5 ensures that, when the substrate 1 and / or the structured functional coating 2 softens during the heat treatment and the molding process, flow processes are largely contained or prevented. The optical quality of the substrate 1 with the structured functional coating 2 can thereby be significantly improved. Visually perceptible disturbances or distortions can be avoided or at least significantly reduced.

[0085] Figure 2a shows a schematic plan view of a substrate 1 coated according to the invention according to an embodiment as a substantially rectangular pane, for example a vehicle pane, for example a vehicle roof pane with a functional coating 2 applied, for example, over the entire surface. The structuring region 3 forms a flat partial region in the functional coating 2, in which the functional coating 2 is structured (here linear). The structuring by forming coating-free regions 4 is shown purely by way of example as stripping in parallel lines. Such structuring is particularly preferably produced by laser ablation. However, other known structuring methods can also be used, as long as the functional coating is structured by mechanical removal in step C) of the process.The dielectric cover layer 5, which is formed according to the invention at least over the entire structuring region 3 and comprises, for example, SiO2, seals in particular the coating-free regions 4 of the substrate surface as well as the edge regions 6 of the functional coating and effectively protects them during a heat treatment and / or a heat-assisted molding process against flow processes, for example, due to the softening of the substrate material, such as glass, or against degradation of the functional coating 2, as well as against corrosive influences in the longer term. The dielectric cover layer 5 can, as shown in Figure 2a, cover and seal a somewhat larger surface area than the structuring region 3.According to the invention, the at least local application of the dielectric cover layer 5 at least over the entire structuring region 3 makes it possible to prevent or at least significantly reduce the previously occurring optical interference and distortions 8 (see Fig. 5a) that occur during heat treatment, and in particular heat treatment in conjunction with a forming process, such as a tempering or bending process. Advantageously, the functionality of the functional coating 2 is not negatively affected by the dielectric cover layer 5.

[0086] Figures 2b and 2c show simplified schematic transverse views of the curved substrate 1 from Figure 2a, wherein the functional coating 2, the structuring region 3, and the dielectric cover layer 5 are not shown separately. The substrate 1, for example a glass pane, is bounded by four side edges: two opposing long side edges (shown at the top and bottom in Figure 2a) and two opposing short side edges. The drawn direct connecting line between the geometric centers of the two long side edges is referred to as the transverse connecting line Q within the meaning of the invention, and the drawn direct connecting line between the geometric centers of the two short side edges is referred to as the longitudinal connecting line L.

[0087] The extent of the bending of the substrate 1 can be described by the maximum deviation occurring from the transverse connecting line Q and the longitudinal connecting line L. In a cross-section through the substrate 1 along the transverse connecting line Q (Fig. 2b), a point on the substrate 1 can be determined whose perpendicular distance to the transverse connecting line Q is never greater than that of all other points. The perpendicular distance of said point to the transverse connecting line Q is referred to in the invention as the transverse bending depth TQ. Likewise, in a cross-section through the substrate 1 along the longitudinal connecting line L (Fig. 2c), a point on the substrate 1 can be determined whose perpendicular distance to the longitudinal connecting line L is greater than that of all other points. The perpendicular distance of said point to the longitudinal connecting line L is referred to in the invention as the longitudinal bending depth TL.

[0088] Figure 3 schematically shows a composite pane 100 in the enlarged section V, which was manufactured by steps A) to H) according to an embodiment of the method according to the invention, starting from a first substrate 1 from Figure 1 e, coated in a structured manner according to the invention, by lamination with a similarly curved pane as the second substrate 10 and a thermoplastic composite film 7.

[0089] Figure 4 shows a plan view of a substrate 1 structured and coated according to the invention. In particular, Figure 4 shows a plan view of an embodiment of a curved pane 1 produced using the method according to the invention to illustrate the dimensions of the pane as referred to in the context of the present invention. The pane is provided, for example, as a component of a composite pane 100, in particular a windshield for a motor vehicle, in particular for a passenger car, and has the typical trapezoidal basic shape with rounded upper and lower edges. The smallest possible quadrilateral suitable for enclosing or receiving the pane 100 is referred to as a 2D box D and is indicated by dashed lines. The largest dimension of this 2D box D is referred to as the length L' and the second largest dimension as the width B'.The length L' and the width B' are determined in a plan view of the wafer 1 or its main surfaces. In the embodiment shown, the wafer 1 also has a trapezoidal structuring region 3, which is covered by a dielectric cover layer 5 and sealed from the environment.

[0090] Figures 5 and 5a show a cross-sectional view of an example according to the prior art without a dielectric cover layer. As shown in Figure 5a, after subjecting the substrate 1 with a structured functional coating 2 without a dielectric cover layer according to the invention to step E), i.e., the heat treatment and optionally the thermal forming process, significant distortions 8 and optical defects are evident, particularly in the coating-free regions 4 and in the edge regions 6 of the structured functional coating 2.

[0091] Reference symbols

[0092] 1 substrate

[0093] 2 functional coating

[0094] 3 Structuring area

[0095] 4 coating-free area (stripped, uncoated)

[0096] 5 dielectric cover layer

[0097] 6 Edge area (of the structured coating)

[0098] 7 thermoplastic composite film / intermediate layer

[0099] 8 optical distortions / deformation

[0100] 10 second substrate

[0101] 100 composite panes

[0102] V Magnifying section

[0103] Q Cross connection line of the substrate (e.g. windshield)

[0104] L Longitudinal connection line of the substrate

[0105] TQ transverse bending depth

[0106] TL Longitudinal bending depth

[0107] L' Length of the substrate (e.g. windshield)

[0108] B' Width of the substrate

[0109] D 2D-Box of Substrates

Claims

Patent claims 1. A method for producing a substrate (1), in particular a vehicle window, with a functional, in particular electrically conductive, structured coating (2) on at least a partial area of ​​a surface of the substrate (1), comprising the steps A) Providing a substrate (1), B) producing the functional coating (2) in at least one partial area on a first surface of the substrate (1), C) Structuring the functional coating (2) in at least one structuring area (3), D) applying a dielectric cover layer (5) at least to the structuring region (3) of the first surface of the substrate (1), E) Heat treatment of the coated substrate (1) from step D), in particular by shaping the substrate (1), wherein the functional coating (2) is structured in step C) by mechanical removal.

2. The method according to claim 1, characterized in that in step D) the dielectric cover layer (5) is applied by flame-assisted chemical vapor deposition (FA-CVD) or by atmospheric pressure chemical vapor deposition (APCVD).

3. Method according to claim 1 or 2, characterized in that the dielectric cover layer (5) is formed in a layer thickness of up to 1 pm, preferably in a layer thickness of 10 nm to 900 nm.

4. The method according to any one of claims 1 to 3, characterized in that the dielectric cover layer (5) produced in step D) comprises at least one of silicon oxide (SiO2), silicon nitride (SiO2), zinc oxide, tin-zinc oxide, silicon-metal mixed nitrides, such as silicon zirconium nitride, zirconium oxide, niobium oxide, hafnium oxide, tantalum oxide, tungsten oxide and silicon carbide, preferably SiO2.

5. Method according to one of claims 1 to 4, characterized in that in step C) the structuring takes place in the form of a pattern comprising at least one line.

6. The method of claim 5, wherein the at least one line has a line width in a range of 0.05 mm to 0.5 mm.

7. Method according to one of claims 1 to 6, characterized in that the mechanical removal in step C) is laser ablation.

8. Method according to one of claims 1 to 7, characterized in that it further comprises the steps F) providing a second substrate (10), which optionally undergoes steps B) to E), and a thermoplastic composite film (7), G) forming a stacking sequence of the first substrate (1) provided in step A), the thermoplastic composite film (7) and the second substrate (10), H) Combining the stacking sequence from step G) under the influence of heat, pressure and / or vacuum to form a composite disc (100).

9. The method according to claim 8, characterized in that the first and the second substrate (1, 10) are formed together in step E), preferably subjected to a bending process together.

10. Substrate (1, 10), in particular vehicle window, with functional, in particular electrically conductive, coating (2) in at least one partial area on at least one surface, produced by a method according to one of claims 1 to 9, characterized in that the functional coating (2) has a structuring area (3) and a dielectric cover layer (5) is applied at least on this structuring area (3).

11. Substrate (1, 10) according to claim 10, characterized in that the dielectric cover layer (5) is a single layer of a dielectric material which comprises at least one of silicon oxide (SiO2), silicon nitride (SiO2N2), zinc oxide, tin-zinc oxide, silicon-metal mixed nitrides, such as silicon zirconium nitride, Zirconium oxide, niobium oxide, hafnium oxide, tantalum oxide, tungsten oxide and silicon carbide, preferably SiC>2.

12. Substrate (1, 10) according to claim 10 or 11, characterized in that the dielectric cover layer (5) has a layer thickness of up to 1 pm, preferably a layer thickness of 10 nm to 900 nm.

13. Substrate (1, 10) according to one of claims 10 to 12, characterized in that the functional coating (2) in the structuring region (3) has a pattern comprising at least one line.

14. Substrate (1, 10) according to claim 13, characterized in that the at least one line has a line width in a range from 0.05 mm to 0.5 mm.

15. Use of a structured coated substrate (1, 10) according to one of claims 10 to 14 for producing a pane of a means of transport on land, on water or in the air, preferably a vehicle pane, in particular a windscreen, roof pane, side window or rear window, or a pane for a building, preferably a window pane, facade pane or door pane.

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