Vehicle roof composite window with heat-reflective inner coating and large communication window

Abstract

Curved laminated glass pane (100) designed as a vehicle roof pane comprising a. at least one first disk (11) with an outer surface (I) and an inner surface (II), b. a second disk (12) with an outer surface (III) and an inner surface (IV) which is congruently connected to the first disk (11) via a thermoplastic intermediate layer (13), wherein c. a heat-radiation reflective coating (6) is applied to the interior surface (IV) of the second disk (12), wherein the heat-radiation reflective coating (6) comprises a transparent conductive oxide selected from the group consisting of indium tin oxide, antimony- or fluorine-doped tin oxide, aluminum-doped zinc oxide (ZnO:Al), gallium-doped zinc oxide (ZnO:Ga) or mixtures thereof, and preferably indium tin oxide, wherein d. a grid surface (8) consisting of intersecting, stripped grid lines (7) is introduced into the heat-radiation-reflecting coating (6), characterized in that the grid lines (7) of the grid surface (8) are introduced into the flat coated second disk (12) as stripped lines parallel to each other, and the disk (12) is subsequently bent in such a way that the grid lines (7) are no longer parallel at least in sections, according to the bending.

Description

[0001] The invention relates to a vehicle roof composite pane with an inner coating that reflects heat rays and a large-area communication window.

[0002] A large number of composite panes with a heat-reflecting interior coating and methods for producing such composite panes are already known, which usually have a metallic coating such as a silver coating as a functional layer, for example, from EP 877 006 B1, EP 1 047 644 B1 and EP 1 917 222 B1. However, such coatings are susceptible to corrosion and not sufficiently mechanically resistant. The coatings therefore cannot be applied to the surface of a pane facing the vehicle interior, where the coating is exposed to air and other environmental influences. WO2011 / 105991A1 discloses a pane with a heat-reflecting coating, which can be applied to its interior-side surface. The coating has a functional layer of indium tin oxide in addition to dielectric layers.US4507547A discloses another pane with a heat radiation reflecting coating with a functional layer of indium tin oxide.

[0003] However, panes with metal-containing or conductive coatings also have disadvantages. For example, radiofrequency radiation is absorbed by many metal-containing coatings. This significantly impairs the functionality of many sensors, navigation, telecommunications, or radio devices. To solve these problems, at least partial stripping of the metal-containing coating is usually necessary. In the case of electromagnetic radiation in the radio frequency range such as FM, AM, UHF, VHF, DAB, mobile telephony in the GSM 900, GSM 1800, and UMTS bands, satellite-based navigation (GPS), or microwave radiation, a net or grid-like stripping is necessary. The grid meshes must have a line spacing that is significantly smaller than the wavelength of the desired electromagnetic radiation.

[0004] Partial decoating can be achieved by masking the area not to be coated or by laser decoating, although this is time-consuming due to the comparatively large surface area to be decoated. Another problem with decoating relatively large areas is that the applied heat is absorbed unevenly during the subsequent manufacturing step of bending the vehicle window. The coated areas absorb heat better and release it more quickly than the decoated areas. This results in local defects and unevenness in the decoated area of ​​the window that cannot be subsequently compensated for. The optical and, in some cases, also the mechanical properties of the finished window deteriorate.

[0005] On the other hand, the metal-containing coatings are removed in lines, for example, using a suitable laser. Since only small portions of the metal-containing coating need to be removed, the infrared-reflecting effect is largely retained, but the radio-frequency communication signals are hardly attenuated and can be received and transmitted through the layer.

[0006] The object of the present invention is to provide an improved curved composite pane for a vehicle roof that offers good functionality with regard to the reflection of thermal radiation into the interior while simultaneously exhibiting very good transmission for communication signals. The composite pane is intended to result in a pane that is as optically and mechanically flawless as possible compared to the coated pane, while simultaneously requiring minimal manufacturing effort.

[0007] The object of the present invention is achieved by a composite pane according to independent claim 1. Preferred embodiments are evident from the subclaims.

[0008] The curved laminated glass pane according to the invention designed as a vehicle roof window comprises a. at least one pane with an outside surface I and an inside surface II, b. a second pane with an outside surface III and an inside surface IV, which is congruently connected to the first pane (1) via a thermoplastic intermediate layer, wherein c. a heat-ray reflecting coating is applied to the interior-side surface IV of the second pane, wherein the heat-ray reflecting coating comprises a transparent conductive oxide selected from the group consisting of indium tin oxide, antimony- or fluorine-doped tin oxide, aluminum-doped zinc oxide (ZnO:Al), gallium-doped zinc oxide (ZnO:Ga) or mixtures thereof, and preferably consists of indium tin oxide, wherein d. a grid surface consisting of intersecting, de-coated grid lines is incorporated into the heat-reflecting coating.

[0009] According to the invention, the grid lines of the grid surface are introduced into the flat coated second pane as mutually parallel stripped lines, and the pane is then bent in such a way that the grid lines no longer run parallel, at least in sections, in accordance with the bend.

[0010] The composite pane according to the invention comprises at least a first pane and a second pane laminated together via a thermoplastic intermediate layer. The composite pane is a vehicle roof composite pane with a three-dimensional curve. The first pane and the second pane each have an inner side and an outer side that run essentially parallel to each other. The thermoplastic intermediate layer connects the inner side of the first pane and the inner side of the second pane in a congruent manner.

[0011] The thermoplastic intermediate layer is formed by one or more thermoplastic polymer films. The thermoplastic films preferably contain polyvinyl butyral (PVB), ethylene-vinyl acetate (EVA), polyurethane (PU), and / or mixtures thereof and / or copolymers thereof, particularly preferably polyvinyl butyral. The films are preferably based on the aforementioned materials, but may contain additional components, for example, plasticizers, colorants, IR or UV absorbers, preferably in a proportion of less than 50%.

[0012] The individual polymer films, in particular the PVB films, preferably have a thickness of approximately 0.025 mm (25 µm) to 1 mm, in particular from 25 µm to 125 µm and from 0.3 mm to 1 mm, for example 50 µm, 100 µm, 0.38 mm, or 0.76 mm. Further properties of the laminated glass pane can be influenced by the thickness of the films. For example, thicker PVB films result in improved sound absorption, particularly if they contain an acoustically effective core, increased burglary resistance of the laminated glass pane, and also increased protection against ultraviolet radiation (UV protection). The thermoplastic interlayer can also comprise other, particularly functional, layers.An example of such a functional layer encompassed by the thermoplastic intermediate layer is a so-called PDLC (polymer dispersed liquid crystal) layer, with which the transparency can be changed by a simple electrical command and thus create privacy.

[0013] In an advantageous embodiment, the thermoplastic intermediate layer is formed from one or more polyvinyl butyral films.

[0014] Furthermore, the thermoplastic intermediate layer can be a functional intermediate layer, in particular an intermediate layer with acoustically damping properties, an intermediate layer that is tinted at least in sections and / or an intermediate layer that is colored at least in sections.

[0015] The thickness of the thermoplastic intermediate layer is preferably between 0.2 mm and 1.0 mm. For example, thermoplastic films with a standard thickness of 0.76 mm can be used.

[0016] The first pane, the second pane, and the thermoplastic interlayer can be clear and colorless, but also tinted or colored. In a preferred embodiment, the total transmittance through the laminated glass is greater than 70%. The term "total transmittance" refers to the method for testing the light transmittance of motor vehicle windows specified in ECE-R 43, Annex 3, Section 9.1.

[0017] The laminated glass is preferably curved in one or more directions of space, as is usual for motor vehicle windows, with typical radii of curvature being in the range of about 10 cm to about 40 m.

[0018] The first pane and / or the second pane can be thermally or chemically toughened, partially toughened or not toughened.

[0019] In an advantageous embodiment of the composite pane according to the invention as a roof pane of a motor vehicle, the first pane is a non-tempered pane. The first pane can be exposed to loads such as stone chips. If a stone, especially a small, sharp stone, strikes a glass pane, it can penetrate its surface. In the case of a tempered pane, the stone can thus penetrate the tensile stress zone inside the pane, causing the pane to shatter. A non-tempered first pane has a broad compressive stress zone and lower tensile stress inside and is therefore less susceptible to impact from a sharp object. A non-tempered first pane is therefore very advantageous overall with regard to the safety of vehicle occupants.

[0020] In a preferred embodiment of the invention, the first pane contains soda-lime glass or borosilicate glass, in particular soda-lime glass. Soda-lime glass is inexpensive and has proven itself for automotive applications.

[0021] The second pane can, in principle, have any chemical composition known to those skilled in the art. For example, the second pane can contain or consist of soda-lime glass or borosilicate glass.

[0022] In an advantageous embodiment of the invention, the second pane is a chemically tempered pane. This tempering can provide the second pane with exceptional fracture stability and scratch resistance. For very thin glass panes, chemical tempering is more suitable than thermal tempering. Since thermal tempering is based on a temperature difference between a surface zone and a core zone, thermal tempering requires a minimum thickness of the glass pane. Sufficient stresses can typically be achieved with commercially available thermal tempering devices for glass thicknesses of approximately 2.5 mm and above. For thinner glass thicknesses, the generally required tempering values ​​cannot usually be achieved (see, for example, ECE Regulation 43).In chemical tempering, the chemical composition of the glass is changed at the surface through ion exchange, with the ion exchange being limited to a surface zone by diffusion. Chemical tempering is therefore particularly suitable for thin panes. Chemical tempering is also commonly referred to as chemical annealing, chemical hardening, or chemical strengthening.

[0023] In the automotive sector, both the stability and fracture resistance of the laminated glass and the lowest possible weight of the glazing are of enormous importance. In this regard, it has been found that an asymmetry of the first and second panes in terms of their thickness has a beneficial effect on the stability of the laminated glass. The thickness of the first pane is generally significantly greater than the thickness of the second pane. Such a thickness asymmetry, with its associated advantages, can also be desirable for the inventive laminated glass with a heat-reflecting coating.

[0024] A composite pane according to the invention can additionally comprise a masking print, in particular made of a dark, preferably black, enamel. The masking print is in particular a peripheral, i.e., frame-like, masking print. The peripheral masking print primarily serves as UV protection for the assembly adhesive of the composite pane. The masking print can be opaque and full-surface. The masking print can also be semi-transparent, at least in sections, for example, as a dot matrix, striped matrix, or checkered matrix. Alternatively, the masking print can also have a gradient, for example, from an opaque covering to a semi-transparent covering.The cover print is usually applied to the interior-side surface of the first pane or to the interior-side surface of the second pane, wherein the cover print is preferably applied to a pane surface on which no heat-ray reflecting coating is arranged in the composite pane according to the invention.

[0025] The heat-reflecting coating can also be referred to as a low-emissivity coating, emissivity-reducing coating, heat-reducing coating, low-E coating, or low-E layer. Its purpose is to reflect thermal radiation, particularly IR radiation, which has a longer wavelength than the IR component of solar radiation.

[0026] The thermal radiation-reflecting coating according to the invention comprises a transparent conductive oxide (TCO) selected from the group consisting of indium tin oxide, antimony- or fluorine-doped tin oxide, aluminum-doped zinc oxide (ZnO:Al), gallium-doped zinc oxide (ZnO:Ga), or mixtures thereof, and preferably consists of indium tin oxide (ITO). This achieves particularly good results with regard to the emissivity and flexibility of the coating according to the invention. It exhibits low absorption and low reflection in the visible spectral range and therefore high transmission. The functional layer exhibits reflective properties against thermal radiation, particularly infrared radiation, but is largely transparent in the visible spectral range.The coating can therefore also be used on panes where a significant reduction in transmission is undesirable or prohibited by law, for example in windshields or front side windows in motor vehicles. This is a major advantage of the invention. The coating according to the invention is also corrosion-resistant. The coating can therefore be applied to the surface of the substrate which is intended to face the interior of a vehicle when the pane is installed. On this surface, the coating according to the invention particularly effectively reduces the emission of thermal radiation from the pane into the interior in summer and the radiation of heat into the outside environment in winter. This achieves particularly good results with regard to the emissivity and flexibility of the coating according to the invention. The refractive index of the material of the functional layer is preferably 1.7 to 2.5.

[0027] The emissivity of the pane according to the invention can be influenced by the thickness of the functional layer. The thickness of the functional layer is preferably from 20 nm to 200 nm, more preferably from 40 nm to 150 nm, and most preferably from 50 nm to 130 nm, for example, approximately 120 nm. Within this range of functional layer thicknesses, particularly advantageous emissivity values ​​and a particularly advantageous ability of the functional layer to withstand mechanical transformation such as bending or tempering without damage are achieved.

[0028] The interior emissivity of the composite pane according to the invention is preferably less than or equal to 50%, particularly preferably from 10% to 50%, and most preferably from 10% to 35%. Interior emissivity refers to the measure indicating how much thermal radiation the pane emits into an interior, for example, a building or vehicle, in its installed position compared to an ideal heat radiator (a black body). For the purposes of the invention, emissivity is understood to mean the normal emissivity at 283 K according to the EN 12898 standard.

[0029] However, the functional layer can also contain other transparent, electrically conductive oxides, tin oxide doped with antimony or fluorine, zinc oxide doped with aluminum (ZnO:Al), zinc oxide doped with gallium (ZnO:Ga) or mixtures thereof.

[0030] The indium tin oxide (ITO) is preferably deposited by means of magnetic field-assisted cathode sputtering using an indium tin oxide target. The target preferably contains from 75 wt.% to 95 wt.% indium oxide and from 5 wt.% to 25 wt.% tin oxide, as well as manufacturing-related admixtures. The indium tin oxide is preferably deposited under a protective gas atmosphere, for example, argon. A small amount of oxygen can also be added to the protective gas, for example, to improve the homogeneity of the functional layer. Alternatively, the target can preferably contain at least from 75 wt.% to 95 wt.% indium and from 5 wt.% to 25 wt.% tin. The indium tin oxide is then preferably deposited with the addition of oxygen as a reaction gas during cathode sputtering.

[0031] According to the invention, the heat-reflecting coating is applied to the surface of the second pane which is intended to face the interior of a vehicle when the pane is in the installed position. The heat-reflecting coating preferably extends over the entire interior-side surface IV of the second pane. This is particularly advantageous with regard to thermal comfort in the interior. The surface which is intended to face the interior when the pane is in the installed position is referred to as the interior-side surface within the meaning of the invention. The coating according to the invention can, at high outside temperatures and in sunlight, at least partially reflect the heat radiation radiated by the entire pane towards the interior.At low outside temperatures, the coating according to the invention can effectively reflect the heat radiation emitted from the interior and thus reduce the effect of the cold window as a heat sink.

[0032] The coating according to the invention can be applied over the entire surface of the initially flat, i.e., not yet curved, second pane. However, the surface of the pane can also have coating-free areas. For example, the surface of the pane can have a coating-free edge area surrounding it, which serves as a fastening and connection area.

[0033] According to the invention, a grid surface consisting of intersecting, de-coated grid lines is introduced into the heat-ray reflecting coating.

[0034] The term "grid surface" in the sense of the invention includes an area within the coating that has a linear removal of the coating, for example, using a laser. The linear removal forms a tile structured with a mesh pattern and appears slightly brighter on the actual pane than the surrounding coating, particularly under grazing light incidence or in reflection. The grid surface preferably has a rectangular basic shape with the removed areas, as described above, in the form of grid lines arranged in a grid pattern. The spacing of the individual grid lines depends on the wavelength of the corresponding electromagnetic radiation for which increased transmission is desired.

[0035] It is known, in particular, to subsequently structure metallic layers or layer systems by mechanically or thermally removing linear lines from the initially continuously deposited layer, or to introduce structures by masking during the deposition process. In particular, extremely narrow lines can be created in the layer using laser beams. According to the present invention, however, an oxide heat-reflecting layer is processed by such linear removal by introducing a grid surface with intersecting grid lines.

[0036] Decoating, and thus the introduction of the grating surface, can also be performed alternatively or cumulatively using masking and unmasking processes. This process results in highly homogeneous layers, which, on the one hand, produces an even clearer optical quality of the pane and, on the other hand, allows for comparably fast processing speeds with the current process.

[0037] The present invention is also based on the finding that a curved pane according to the invention, even with stripped line structures that are not completely parallel, has sufficiently high permeability for high-frequency electromagnetic radiation. In other words, the strippings initially introduced as parallel grid lines in the finished curved pane have, at least in some sections, unequal – or, in other words, irregular – spacings from one another. This makes the pane according to the invention easy to distinguish from previously known panes. Furthermore, it is not necessary to strip the transparent, electrically conductive coating over a large area. Stripped structures with only a small line width, which do not significantly impair the optical transparency and the aesthetic appearance of the pane, are sufficient.The structures, which are at least partially non-parallel, can advantageously lead to fewer disruptive field-induced currents developing. Furthermore, high permeabilities for high-frequency electromagnetic radiation (communications radiation) can be achieved with very little structuring effort. At the same time, process time and costs can be kept low. This is primarily due to the fact that during structuring—that is, during the introduction of the stripped linear regions into the conductive coating of the initially flat wafer—a continuous laser movement can be performed without numerous settling points and the associated repositioning. In this way, a significantly faster structuring process time can be achieved.Likewise, masking can be used for decoating by means of suitable preparations known to the person skilled in the art, which, in terms of process time, is currently no less rapid in production than decoating by laser.

[0038] A further advantage of the composite pane according to the present invention is that a freely positionable grid surface is now provided as a communication window, so that the vehicle occupants experience a high degree of reliability in the transmission of communication signals. Unlike vehicle windshields with a communication window of the generic type, which are kept comparatively small and primarily arranged only in edge regions due to the strict specifications for the viewing areas of a windshield, the composite pane according to the invention for a vehicle roof provides for the grid surface serving as a communication window to be freely positionable, in particular arranged in a central region or near the edge of the pane. At the same time, the functionality of the heat-reflecting coating, which ensures good thermal comfort, is fully retained.

[0039] In one embodiment of the invention, the heat-ray reflecting coating is applied directly to the interior surface IV of the second pane.

[0040] In a further embodiment of the composite pane according to the invention, the heat-ray reflecting coating comprises an adhesion-promoting layer and / or a cover layer.

[0041] In one embodiment of the present invention, the grating lines have a width of 40 µm to 250 µm, preferably of 70 µm to 200 µm.

[0042] In one embodiment of the invention, the spacing between aligned (parallel) grid lines is from 0.3 mm to 10 mm, preferably from 0.5 mm to 5.0 mm. Such spacings are technically simple to produce, for example, by laser structuring. Furthermore, they hardly impair the optical transparency through the pane and enable sufficient transparency for high-frequency electromagnetic radiation, especially for radio and radar radiation.

[0043] In a further embodiment of the composite pane according to the invention, the maximum deviation in the spacing of the previously parallel grid lines caused by the subsequent bending of the pane is between 100 µm and 5.00 mm, preferably between 150 µm and 2.00 mm. This deviation can be easily measured by comparing the relevant spacing between two parallel lines of a grid tile before bending and the spacing between the same lines after bending.

[0044] The aforementioned maximum deviation in the spacing of the previously parallel grid lines, i.e., the linear stripping introduced into the flat pane as parallel grid lines before bending, which is caused by subsequent bending, enables very good transparency for communication signals. Compared to a completely stripped surface of the same size, a composite pane with the grid surface according to the invention exhibits only approximately 1 dB more signal attenuation.

[0045] In an advantageous embodiment of the composite pane according to the invention, the grid surface extends across the entire width of the second pane. Alternatively, however, the surface area of ​​the grid surface can also be greater than 95% of the width of the pane, i.e. the grid surface spans almost the entire width of the pane. With this surface area, particularly low transmission attenuation and favorable distribution of the received and transmitted power behind the pane can be achieved. At the same time, a favorable ratio of improved transmission to the process costs for decoating can be achieved, since any necessary masking of the areas not to be coated can be omitted. The term "width of the pane" in this case refers to the extent of the vehicle roof in the installed position transverse to the direction of travel.In contrast, the term “window length” refers to the extent of the vehicle roof along the direction of travel.

[0046] In a further advantageous embodiment of the invention, the grid surface is arranged on the second pane in such a way that it completely covers at least the area where additional antennas are provided in or on the vehicle roof window. This ensures that a very large area can be used as a communication window and that the communication signals can be reliably transmitted.

[0047] In contrast to the communication windows in windshields previously known in the automotive sector, the grid surface in this composite vehicle roof pane not only offers a comparatively large area, but also advantageously allows for flexible positioning within the pane, allowing it to be adapted, for example, to areas with one or more antennas. Optical or mechanical disturbances to the pane are avoided despite the integration of the grid surface into the flat pane and subsequent bending during production. Production is inexpensive and straightforward.

[0048] In a preferred embodiment of the present invention, the intersecting grid lines are introduced parallel and orthogonal or at an angle of approximately 45° to the longitudinal edge of the flat second disc before bending.

[0049] This creates either a visually linear pattern with essentially rectangular or square grid lines, or a pattern of grid lines at an angle to the longitudinal edge of the window and thus to the direction of travel, creating a diamond-like appearance. This particularly contributes to greater freedom in the design of the vehicle roof. All advantageous functions are retained. However, simple and rapid production is also ensured, so that few set-off points and changes in direction are required during stripping.

[0050] In a further embodiment of the invention, the composite pane has a black printing area in the area of ​​the grid surface.

[0051] This virtually conceals the visual difference in the area where the grid surface is applied. The black print area can be provided, in particular, in layers above the second pane, for example, on surface III of the second pane, as a coloring of the thermoplastic intermediate layer, or on one of the two surfaces of the first pane. It can be created, for example, by a black enamel print or by a functionally comparable black coloring.

[0052] Especially in combination with antennas provided in the same area, an invisible communication window is created, which preferably runs across the entire width of the vehicle roof window.

[0053] The invention further comprises a method for producing a curved composite pane designed as a vehicle roof pane, comprising at least the steps: a) Providing a first pane with an outside surface I and an inside surface II, a second pane with an outside surface III and an inside surface IV, and at least one thermoplastic intermediate layer, wherein a heat-reflecting coating is applied to the inside surface IV of the second pane, wherein the heat-reflecting coating comprises a transparent conductive oxide selected from the group consisting of indium tin oxide, antimony- or fluorine-doped tin oxide, aluminum-doped zinc oxide (ZnO:Al), gallium-doped zinc oxide (ZnO:Ga) or mixtures thereof, and preferably consists of indium tin oxide, b) introducing a grid surface of intersecting, de-coated grid lines into the heat-reflecting coating of the second pane, wherein the grid lines of the grid surface are introduced into the flat coated second pane as mutually parallel de-coated lines, c) bending the first disc and bending the coated second disc with the grid surface removed, such that the grid lines are no longer parallel, at least in sections, according to the bending, d) forming a stacking sequence of the first pane, the at least one thermoplastic intermediate layer and the second pane such that the interior surface II of the first pane and the exterior surface III of the second pane face each other and the at least one thermoplastic intermediate layer is arranged between the first pane and the second pane; e) joining the first pane and the second pane via the at least one thermoplastic intermediate layer to form a composite pane in a lamination process.

[0054] In other words, the method according to the invention provides a simple and efficient method for producing a vehicle roof panel with a comparatively large grid area to improve the permeability of communication signals. In particular, no additional steps or complex adjustments are required for decoating, and the process speed is correspondingly high.

[0055] In step a), a heat-reflecting coating is applied to the interior-side surface IV of the second pane. The heat-reflecting coating comprises a transparent conductive oxide selected from the group consisting of indium tin oxide, antimony- or fluorine-doped tin oxide, aluminum-doped zinc oxide (ZnO:Al), gallium-doped zinc oxide (ZnO:Ga), or mixtures thereof, and preferably consists of indium tin oxide. The heat-reflecting coating is preferably applied by physical vapor deposition (PVD) to the interior-side surface IV of the inner pane and / or to the exterior-side surface I of the outer pane, particularly preferably by cathode sputtering, most particularly preferably by magnetic-field-assisted cathode sputtering.

[0056] In step b), a grid surface consisting of intersecting, stripped grid lines is introduced into the heat-reflecting coating of the second pane. The grid lines of the grid surface are introduced into the flat, coated second pane as mutually parallel stripped lines.

[0057] It is known to those skilled in the art to subsequently structure, in particular, metallic layers or layer systems by mechanically or thermally removing linear lines from the initially continuously deposited layer, or to introduce structures by masking during the deposition process. In particular, extremely narrow lines can be created in the layer using laser beams. According to the present invention, however, an oxide heat-reflecting layer is processed by such linear removal by introducing a grid surface with intersecting grid lines.

[0058] The laser is preferably guided at a speed of 100 mm / s to 60,000 mm / s. The laser preferably has a power of 1 W to 10 kW and / or preferably comprises a carbon dioxide, YAG, Nd-YAG, ytterbium-YAG, holmium-YAG, erbium-YAG, neodymium-glass, excimer, fiber, disk, slab, or diode laser. The laser is preferably guided via a plotter.

[0059] The coated surface of the second pane can face the laser. If the pane is (largely) transparent to the laser radiation (particularly in the case of a glass pane), the coated surface can alternatively face away from the laser, and the laser radiation can be directed through the pane onto the coating. In both cases, the laser radiation is preferably focused onto the surface of the pane with the coating. The extent of the laser spot on the coating (diameter) is preferably from 25 µm to 250 µm, particularly preferably from 40 µm to 180 µm.

[0060] Laser radiation in the UV, visible, or IR range of the electromagnetic spectrum is preferably used. The wavelength of the laser radiation is preferably from 200 nm to 2000 nm, particularly preferably from 250 nm to 1100 nm, for example from 355 nm to 1064 nm. This achieves particularly good results. Solid-state lasers (e.g., Nd:YAG lasers or Yb:YAG lasers) can be used, which can be frequency-doubled, frequency-tripled, or frequency-doubled if necessary. Such lasers are widely used industrially, relatively inexpensive, and efficient. Alternatively, diode lasers, excimer lasers, gas lasers, or dye lasers can also be used.

[0061] The laser is preferably operated in pulsed mode. The pulse length of the laser is preferably in the femtosecond or nanosecond range. The pulse length is preferably at most 500 ns, more preferably at most 300 ns. The pulse length is very particularly preferably from 500 fs to 200 ns, in particular from 10 ps to 100 ns. This achieves particularly good results. Such short pulses, in particular, minimize the thermal stress in the laser processing environment, so that the processing of thin films and even heat-sensitive materials is possible. The repetition frequency of the laser pulses is preferably from 10 kHz to 1000 kHz, more preferably from 50 kHz to 400 kHz. The pulse energy is preferably from 1 mJ to 50 µJ, more preferably from 800 µJ to 20 µJ, most preferably from 500 µJ to 50 µJ.

[0062] The output power of the laser is preferably from 10 W to 1000 W, preferably from 40 W to 500 W.

[0063] The laser radiation used can be adapted to the coating being processed in order to achieve effective ablation of at least the oxide coating, and possibly also other layers, in the communication area to be created. This is achieved in particular by selecting the wavelength, laser power, pulse energy, and pulse length. All of these parameters have an impact and can be selected accordingly. Furthermore, the effectiveness of the ablation can also be adjusted by appropriately selecting the speed and frequency of the laser beam.

[0064] Decoating, and thus the introduction of the grating surface, can also be performed alternatively or cumulatively using masking and unmasking processes. This process results in highly homogeneous layers, which, on the one hand, produce an even clearer optical quality of the disc, and, on the other hand, in the current process, results in process times comparable to those achieved with laser decoating.

[0065] In a further step, the coated and (partially) structured second pane is bent in the range of the softening temperature of the respective glass. In this case, the composite pane designed as a vehicle roof pane is to be bent, so the first pane and the second pane are preferably subjected to a bending process before lamination and in any case after the coating and decoating processes to introduce the grid surface into the coating of the second pane. The first pane and the second pane are preferably bent congruently together (i.e. simultaneously and using the same tool) because this ensures that the shape of the panes is optimally coordinated for the subsequent lamination. Typical temperatures for glass bending processes are, for example, 500°C to 700°C.

[0066] Lamination is preferably carried out under the influence of heat, vacuum, and / or pressure. Known lamination processes can be used, for example, autoclave processes, vacuum bag processes, vacuum ring processes, calender processes, vacuum laminators, or combinations thereof.

[0067] Advantageously, the method according to the invention produces a vehicle roof pane as a composite pane that has very good functionality in terms of heat-reflecting properties and, at the same time, has a large window area for the passage of communication signals. The manufacturing method can be carried out without additional steps and, in particular, without high adjustment effort when introducing the grid surface, compared to known methods. It was surprisingly found that, during the decoating step, the flat second pane can be decoated using geometrically simple and straight lines, which keeps the effort low both in the case of laser decoating and in the case of the masking and unmasking process. The subsequent bending of the pane structured in this way, preferably together with the first pane, produces deviations from the parallelism of the grid lines, at least in some sections.However, it was found that these deviations did not attenuate the transmission of the communication signals, or only very slightly. A comparative measurement of a pane manufactured according to the invention and a pane with a completely decoated coating revealed an increase in the communication signal attenuation of only approximately 0.1 dB.

[0068] In a further embodiment of the method according to the invention, the heat-reflecting coating is stripped in such a way that the grid surface formed thereby extends over the entire width of the second pane.

[0069] In a preferred embodiment of the method, the grid surface is arranged on the second pane such that it completely covers at least the area in which additional antennas are provided in or on the vehicle roof window. The attachment of the antenna(s) can be integrated into the process as desired. For example, the antenna(s) can be subsequently attached, e.g., glued, to the interior-side surface IV of the second pane, either in the area of ​​the coating (structured or non-structured area) or in an area that is free of coating.

[0070] In a further embodiment of the process, a black print is additionally applied to the grid area. Here, too, the step of applying the black print can be integrated into the process at any time. For example, the black print can be applied as an enamel print on the outside of the first pane.

[0071] 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, without departing from the scope of the present invention.

[0072] The invention will now be explained in more detail using exemplary embodiments, with reference to the accompanying figures. The figures do not limit the invention in any way. They show, in a simplified representation, not to scale: Fig. 1 a highly schematic perspective view of a composite pane designed as a vehicle roof according to an embodiment of the invention, Fig. 2 a highly schematic representation of the individual steps for producing a vehicle roof window according to the invention and Fig. 3 a highly schematic, simplified cross-sectional view of a vehicle roof window according to the invention.

[0073] In Fig. 1 shows a curved laminated glass pane 100 designed as a vehicle roof window in a highly schematic perspective view. The laminated glass pane 100 is curved at least in sections both in the longitudinal direction L and in the transverse direction B. According to the invention, it comprises a first pane 11 with an outside surface I and an interior surface II, a second pane 12 with an outside surface III and an interior surface IV, which is congruently bonded to the first pane 1 via a thermoplastic intermediate layer 13, and a heat-ray-reflecting coating 6, which is applied to the interior surface IV of the second pane 12.The heat-reflecting coating 6 comprises a transparent conductive oxide selected from the group consisting of indium tin oxide, antimony- or fluorine-doped tin oxide, aluminum-doped zinc oxide (ZnO:Al), gallium-doped zinc oxide (ZnO:Ga), or mixtures thereof, and preferably consists of indium tin oxide. A grid surface 8 composed of intersecting, stripped grid lines 7 is incorporated into the heat-reflecting coating 6. The grid lines 7 of the grid surface 8 are incorporated into the flat, coated second pane 12 as mutually parallel stripped lines, and the pane 12 is subsequently bent such that the grid lines 7 are no longer parallel, at least in sections, due to the bend. In the embodiment of the invention shown, the grid surface 8 is arranged in the front edge region of the vehicle roof pane and extends almost across the entire width of the pane 100.Additionally, one or preferably several antennas 15 are positioned in the same area, as indicated here. The enlarged detail also shows purely schematically that the strippings previously introduced as parallel stripped grid lines no longer run parallel, at least in some sections, in the subsequently bent pane. Depending on the introduced bend, both the grid lines running in the longitudinal direction and the lines running in the transverse direction may exhibit deviations from the original parallelism.

[0074] The present invention is also based on the finding that a curved pane 100 according to the invention, even with stripped line structures 7 that are not completely parallel, has a sufficiently high permeability for high-frequency electromagnetic radiation. In other words, the strippings initially introduced as parallel grid lines in the finished curved pane 100 have, at least in sections, unequal—or, in other words, irregular—distances from one another. This makes the pane according to the invention easy to distinguish from previously known panes. Furthermore, it is not necessary to strip the transparent, electrically conductive coating over a large area. Stripped structures with only a small line width, which do not significantly impair the optical transparency and the aesthetic appearance of the pane, are sufficient.The structures, which are at least partially non-parallel, can advantageously lead to fewer disruptive field-induced currents being able to develop. Furthermore, high permeabilities for high-frequency electromagnetic radiation (communication radiation) can be achieved with very little structuring effort. At the same time, the process time and process costs can be kept low. This is primarily due to the fact that during structuring, i.e., during the introduction of the stripped linear regions 7 into the conductive coating 6 of the initially flat disk 12, a continuous movement of the laser can be carried out without numerous settling points and the associated repositioning. In this way, a significantly faster process time for structuring can be achieved.Likewise, masking can be used for decoating by means of suitable preparations known to the person skilled in the art, which, in terms of process time, is currently no less rapid in production than decoating by laser.

[0075] Fig. 2 shows purely schematically essential steps for producing a vehicle roof window 100 according to the invention.

[0076] In step a), a heat-reflecting coating 6 is applied to the interior-side surface IV of the second pane. The heat-reflecting coating 6 comprises a transparent conductive oxide selected from the group consisting of indium tin oxide, antimony- or fluorine-doped tin oxide, aluminum-doped zinc oxide (ZnO:Al), gallium-doped zinc oxide (ZnO:Ga), or mixtures thereof, and preferably consists of indium tin oxide. The heat-reflecting coating 6 is preferably applied by physical vapor deposition (PVD) to the interior-side surface IV of the inner pane and / or to the exterior surface I of the outer pane, particularly preferably by cathode sputtering, most particularly preferably by magnetic-field-assisted cathode sputtering.

[0077] In step b), a grid surface 8 consisting of intersecting, stripped grid lines 7 is introduced into the heat-reflecting coating 6 of the second pane 12. The grid lines 7 of the grid surface 8 are introduced into the flat, coated second pane 12 as mutually parallel stripped lines.

[0078] It is known to those skilled in the art to subsequently structure, in particular, metallic layers or layer systems by mechanically or thermally removing linear lines from the initially continuously deposited layer, or to introduce structures by masking during the deposition process. In particular, extremely narrow lines can be created in the layer using laser beams. According to the present invention, however, an oxide heat-reflecting layer 6 is processed by such linear removal by introducing a grid surface 8 with intersecting grid lines 7.

[0079] The laser is preferably guided at a speed of 100 mm / s to 60,000 mm / s. The laser preferably has a power of 1 W to 10 kW and / or preferably comprises a carbon dioxide, YAG, Nd-YAG, ytterbium-YAG, holmium-YAG, erbium-YAG, neodymium-glass, excimer, fiber, disk, slab, or diode laser. The laser is preferably guided via a plotter.

[0080] The coated surface of the second pane 12 can face the laser. If the pane is (largely) transparent to the laser radiation (particularly in the case of a glass pane), the coated surface can alternatively face away from the laser, and the laser radiation can be directed through the pane onto the coating. In both cases, the laser radiation is preferably focused onto the surface of the pane with the coating. The extent of the laser spot on the coating (diameter) is preferably from 25 µm to 250 µm, particularly preferably from 40 µm to 180 µm.

[0081] Laser radiation in the UV, visible, or IR range of the electromagnetic spectrum is preferably used. The wavelength of the laser radiation is preferably from 200 nm to 2000 nm, particularly preferably from 250 nm to 1100 nm, for example from 355 nm to 1064 nm. This achieves particularly good results. Solid-state lasers (e.g., Nd:YAG lasers or Yb:YAG lasers) can be used, which can be frequency-doubled, frequency-tripled, or frequency-doubled if necessary. Such lasers are widely used industrially, relatively inexpensive, and efficient. Alternatively, diode lasers, excimer lasers, gas lasers, or dye lasers can also be used.

[0082] The laser is preferably operated in pulsed mode. The pulse length of the laser is preferably in the femtosecond or nanosecond range. The pulse length is preferably at most 500 ns, more preferably at most 300 ns. The pulse length is very particularly preferably from 500 fs to 200 ns, in particular from 10 ps to 100 ns. This achieves particularly good results. Such short pulses, in particular, minimize the thermal stress in the laser processing environment, so that the processing of thin films and even heat-sensitive materials is possible. The repetition frequency of the laser pulses is preferably from 10 kHz to 1000 kHz, more preferably from 50 kHz to 400 kHz. The pulse energy is preferably from 1 mJ to 50 µJ, more preferably from 800 µJ to 20 µJ, most preferably from 500 µJ to 50 µJ.

[0083] The output power of the laser is preferably from 10 W to 1000 W, preferably from 40 W to 500 W.

[0084] The laser radiation used can be adapted to the coating being processed in order to achieve effective ablation of at least the oxide coating, and possibly also other layers, in the communication area to be created. This is achieved in particular by selecting the wavelength, laser power, pulse energy, and pulse length. All of these parameters have an impact and can be selected accordingly. Furthermore, the effectiveness of the ablation can also be adjusted by appropriately selecting the speed and frequency of the laser beam.

[0085] The decoating and thus the introduction of the grating surface 8 can also be carried out alternatively or cumulatively using masking and demasking processes. This process results in highly homogeneous layers, which, on the one hand, produces an even clearer optical quality of the pane, and, on the other hand, results in comparably short processing times compared to laser decoating in the current process.

[0086] In a further step c), the coated and (partially) structured second pane 12 is bent in the range of the softening temperature of the respective glass. In the present case, the composite pane 100 designed as a vehicle roof pane is to be bent, therefore the first pane 11 and the second pane 12 are preferably subjected to a bending process before lamination and in any case after the coating processes and decoating to introduce the grid surface 8 into the coating 6 of the second pane 12. Preferably, the first pane 11 and the second pane 12 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 subsequent lamination. Typical temperatures for glass bending processes are, for example, 500°C to 700°C.

[0087] Advantageously, the method according to the invention produces a vehicle roof pane 100 as a composite pane, which exhibits very good functionality with regard to heat-reflecting properties and, at the same time, has a large window 8 for the passage of communication signals. The manufacturing method can be carried out without additional steps and, in particular, without significant adjustment effort when introducing the grid surface 8, compared to known methods. It was surprisingly found that, during the decoating step, the flat second pane 12 can be decoated with geometrically simple and straight lines, which minimizes the effort required both in the case of laser decoating and in the case of the masking and unmasking process. The subsequent bending of the thus structured pane 12, preferably together with the first pane 11, produces deviations from the parallelism of the grid lines 7, at least in some sections.However, it was found that these deviations did not attenuate the transmission of the communication signals, or only very slightly. A comparative measurement of a pane manufactured according to the invention and a pane with a completely decoated coating revealed an increase in the communication signal attenuation of only approximately 0.1 dB.

[0088] In Fig.3 shows a highly simplified cross-sectional view of a layer arrangement of a vehicle roof window 100 according to the present invention. The curved window 100 with its first window 11 and its second window 12 is shown straight, i.e. not curved, for the sake of clarity. According to the invention, it comprises a first window 11 with an outside surface I and an inside surface II, a second window 12 with an outside surface III and an inside surface IV, which is congruently connected to the first window 1 via a thermoplastic intermediate layer 13, and a heat-ray reflecting coating 6, which is applied to the inside surface IV of the second window 12.The heat-reflecting coating 6 comprises a transparent conductive oxide selected from the group consisting of indium tin oxide, antimony- or fluorine-doped tin oxide, aluminum-doped zinc oxide (ZnO:Al), gallium-doped zinc oxide (ZnO:Ga), or mixtures thereof, and preferably consists of indium tin oxide. A grid surface composed of intersecting, stripped grid lines 7 is incorporated into the heat-reflecting coating 6. The grid lines 7 of the grid surface 8 are incorporated into the flat, coated second pane 12 as mutually parallel stripped lines, and the pane 12 is subsequently bent such that the grid lines 7 are no longer parallel, at least in sections, due to the bend. In addition, two antennas 15 are positioned in the region of the grid surface 8.The illustrated region of the pane 100 provided with grid lines 7 further comprises a black print 14, which in the present embodiment is applied to surface I of the first pane 11. However, it can equally be provided on an inner surface (II, III) of the composite pane. This virtually conceals the optical difference of the region in which the grid surface 8 is incorporated. The black print region can be provided in particular in layers above the second pane 12, for example on surface III of the second pane 12, as a coloring of the thermoplastic intermediate layer 13, or on one of the two surfaces of the first pane. It can be produced, for example, by a black enamel print or by a functionally comparable black coloring.

[0089] In particular, in combination with antennas 15 provided in the same area, an invisible communication window is created which preferably runs across the entire width of the vehicle roof window 100. List of reference symbols 100 vehicle roof laminated glass panes 2 vehicles 6 Heat-reflecting coating 7 grid lines 8 Grid area 11 first disc 12 second disc 13 thermoplastic intermediate layer 14 Black printing 15 Antenna I first surface of the first disc II second surface of the first disc III first surface of the second disc IV second surface of the second disc L Longitudinal direction of the vehicle window including bend B Transverse direction of the vehicle window including bending QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] EP 877 006 B1

[0002] EP 1 047 644 B1

[0002] EP 1 917 222 B1

[0002] WO 2011 / 105991A1

[0002] US 4507547A

[0002]

Claims

[1] Curved laminated glass pane (100) designed as a vehicle roof pane comprising a. at least one first pane (11) having an outside surface (I) and an inside surface (II), b. a second pane (12) having an outer surface (III) and an inner surface (IV), which is congruently connected to the first pane (11) via a thermoplastic intermediate layer (13), wherein c. a heat-ray reflecting coating (6) is applied to the interior-side surface (IV) of the second pane (12), wherein the heat-ray reflecting coating (6) comprises a transparent conductive oxide selected from the group consisting of indium tin oxide, antimony- or fluorine-doped tin oxide, aluminum-doped zinc oxide (ZnO:Al), gallium-doped zinc oxide (ZnO:Ga) or mixtures thereof, and preferably consists of indium tin oxide, wherein d. a grid surface (8) made up of intersecting, de-coated grid lines (7) is incorporated into the heat-ray reflecting coating (6) characterized by that the grid lines (7) of the grid surface (8) are introduced into the flat coated second disc (12) as mutually parallel stripped lines, the disc (12) is then bent in such a way that the grid lines (7) no longer run parallel, at least in sections, in accordance with the bend. [2] Laminated glass pane according to claim 1, characterized by that the heat-ray reflecting coating (6) is applied directly to the interior-side surface (IV) of the second pane (12). [3] Laminated glass pane according to claim 1 or 2, characterized by that the heat-ray reflecting coating (6) comprises an adhesion-promoting layer and / or a cover layer. [4] Laminated glass pane according to one of claims 1 to 3, characterized bythat the grid lines (7) have a width of 40 µm to 250 µm, preferably of 70 µm to 200 µm. [5] Laminated glass pane according to one of claims 1 to 4, characterized by that the distance between parallel grid lines (7) is from 0.3 mm to 10 mm, preferably from 0.5 mm to 5 mm. [6] Laminated glass pane according to one of claims 1 to 5, characterized by that the maximum deviation in the distance between the previously parallel grid lines (7) caused by the subsequent bending of the disc (12) is between 100 µm and 5.00 mm, preferably between 150 µm and 2.00 mm. [7] Laminated glass pane (100) according to one of claims 1 to 6, characterized by that the grid surface (8) extends over the entire width of the second disc (12). [8] Laminated glass pane (100) according to one of claims 1 to 7, characterized bythat the grid surface (8) is arranged on the second pane (12) in such a way that it completely covers at least the area in which antennas (15) are provided in or on the vehicle roof window (100). [9] Laminated glass pane (100) according to one of claims 1 to 8, characterized by that the intersecting grid lines (7) are parallel and orthogonal or at an angle of approximately 45° to the longitudinal edge of the flat second disc (12) before bending. [10] Laminated glass pane (100) according to one of claims 1 to 9, characterized by that the composite pane (100) has a black printing area (14) in the area of the grid surface (8).

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