Composite pane with IR-reflective coating

Abstract

The invention relates to a composite pane comprising an outer pane (1) and an inner pane (2), which are connected together via a thermoplastic intermediate layer (3), and to an IR-reflective coating (20) on the outer pane (1) or inner pane (2) surface (II, III) facing the intermediate layer (3). The IR-reflective coating (20) comprises three silver layers (21.1, 21.2, 21.3), wherein each silver layer (21.1, 21.2, 21.3) is arranged between two dielectric layers or layer sequences (M1, M2, M3, M4). The aim of the invention is to design the IR-reflective coating (20) such that the coating can be provided with insulating lines (5) which are visually inconspicuous. According to a first approach, the IR-reflective coating (20) is configured so as to have a very low degree of reflection. According to a second approach, the IR-reflective coating (20) is configured so as to have a reflection color which is similar to that of the lowermost dielectric layer or layer sequence (M1).

Description

[0001] Composite pane with an IR-reflective coating

[0002] The invention relates to a composite pane with an IR-reflecting coating, a method for its production and its use.

[0003] It is known that laminated glass can be provided with transparent IR-reflective coatings. Such coatings are commonly used, for example, for vehicle windows. The coatings can reduce the heating of the vehicle interior and thereby improve thermal comfort in the vehicle. Such coatings typically contain metallic layers, particularly those based on silver. Reference is made to WO003 / 024155, US2007 / 0082219A1, US2007 / 0020465A1, WO2013 / 104438, or WO2013 / 104439, for example only. The corrosion-prone IR-reflective coatings are typically arranged inside the laminated glass, so that they have no contact with the surrounding atmosphere.

[0004] The metallic layers are not transparent to electromagnetic radiation, such as that used in mobile communications or GPS signals, particularly high-frequency radiation. To ensure the transmission of this radiation, uncoated areas can be provided as so-called data transmission or communication windows. However, these uncoated areas are visually conspicuous and reduce the thermal insulation effect of the composite pane. Alternatively, it is common to introduce thin insulation lines into the coating using laser radiation, along which the metallic layers are separated. The insulation lines can extend, for example, in the form of a grid over a region of the composite pane or even over the entire composite pane. For example, see EP2586610B1, WG2014033007A1, EP2774898A1, and WO2014135296A1.

[0005] However, even such thin insulation lines can be visually noticeable and thus detract from the appearance of the laminated pane. This is due in particular to the different reflective behavior of the coating on the one hand and the insulation lines on the other. The insulation lines are therefore clearly visible to an observer, at least under certain lighting conditions and viewing angles. The present invention is based on the object of providing an improved laminated pane with an IR-reflective coating. The coating should be suitable for being provided with insulation lines without them being visually noticeable.

[0006] The composite pane according to the invention comprises an outer pane and an inner pane, which are bonded together via a thermoplastic intermediate layer. It also comprises an IR-reflecting coating on the surface of the outer pane or the inner pane facing the intermediate layer. Starting from said surface, the IR-reflecting coating comprises, in the specified order: a first dielectric layer or layer sequence, a first silver layer, a second dielectric layer or layer sequence, a second silver layer, a third dielectric layer or layer sequence, a third silver layer, and a fourth dielectric layer or layer sequence.

[0007] It has been shown that the optical and thermal properties of the IR-reflecting coating are particularly advantageous when it is applied to the surface of the inner pane facing the intermediate layer, which is therefore preferred.

[0008] A first solution according to the invention (Solution A) is based on the approach of designing the IR-reflective coating in such a way that it exhibits only very low reflection in the visible spectral range. The coating is therefore also color-neutral, so that the insulation lines do not lead to visually noticeable color changes.

[0009] The object of the invention is achieved according to solution A by a composite pane with the features mentioned above, wherein each silver layer has a thickness which deviates by at most 5% from the mean value of the thicknesses of all silver layers, the optical thickness of the first dielectric layer or layer sequence is less than the optical thickness of the fourth dielectric layer or layer sequence, the optical thickness of the fourth dielectric layer or layer sequence is less than the optical thickness of the second dielectric layer or layer sequence, the optical thickness of the second dielectric layer or layer sequence is less than the optical thickness of the third dielectric layer or layer sequence.The inventors have recognized that the desired low reflection of the IR-reflecting coating can be achieved if the thickness of the silver layers is selected to be the same or only slightly different, and the optical thicknesses of the dielectric layers or layer sequences are selected in the order of priority according to the invention. The resulting coating exhibits only low reflection and consequently a neutral reflection color. If an insulation line is introduced into the coating, this does not lead to a noticeable change in the reflectance or reflection color. In addition, very high light transmission is achieved, so that the differences in light absorption between the insulation line and the complete coating are minimal. The insulation line remains visually unobtrusive and does not cause a distracting eye-catcher. This is the great advantage of the invention according to solution A.

[0010] In an advantageous embodiment of the invention according to solution A, the ratio of the optical thickness of the first dielectric layer or layer sequence to the optical thickness of the fourth dielectric layer or layer sequence is from 0.7 to 0.95, preferably 0.8 to 0.9, the ratio of the optical thickness of the fourth dielectric layer or layer sequence to the optical thickness of the second dielectric layer or layer sequence is from 0.5 to 0.8, preferably from 0.6 to 0.7, the ratio of the optical thickness of the second dielectric layer or layer sequence to the optical thickness of the third dielectric layer or layer sequence is from 0.7 to 0.95, preferably from 0.8 to 0.9.

[0011] This achieves particularly good results in terms of low reflection of the IR-reflective coating.

[0012] Particularly good results are achieved when the optical thickness of the first dielectric layer or layer sequence is from 50 nm to 100 nm, preferably from 60 nm to 90 nm, particularly preferably from 70 nm to 80 nm, very particularly preferably from 73 nm to 77 nm, the optical thickness of the second dielectric layer or layer sequence is from 115 nm to 165 nm, preferably from 125 nm to 155 nm, particularly preferably from 135 nm to 145 nm, very particularly preferably from 138 nm to 142 nm, the optical thickness of the third dielectric layer or layer sequence is from 140 nm to 190 nm, preferably from 150 nm to 180 nm, particularly preferably from 160 nm to 170 nm, very particularly preferably from 163 nm to 167 nm, and the optical thickness of the fourth dielectric layer or layer sequence is from 65 nm to 115 nm, preferably from 75 nm to 105 nm, particularly preferably from 85 nm to 95 nm, most preferably from 88 nm to 92 nm.

[0013] In solution A, each silver layer preferably has a thickness that deviates by no more than 3%, particularly preferably by no more than 2%, from the mean value of the thicknesses of all silver layers.

[0014] The sum of the thicknesses of the silver layers is preferably from 20 nm to 40 nm, particularly preferably from 25 nm to 35 nm and most preferably from 28 nm to 32 nm. This is advantageous with regard to a high transparency of the coating.

[0015] In an advantageous embodiment of the invention according to solution A, the thickness of all silver layers is from 10 nm to 11 nm, in particular from 10.0 nm to 11.0 nm. This achieves particularly good results with regard to low reflection of the IR-reflecting coating.

[0016] If the silver layers have different thicknesses, it is advantageous if the thickness of the second silver layer is greater than the thickness of the first silver layer and the thickness of the first silver layer is in turn greater than the thickness of the third silver layer.

[0017] The composite pane with the IR-reflective coating according to solution A preferably has a reflection of less than 10%. The reflection of the IR-reflective coating itself, i.e., without the reflections on the glass surfaces, is preferably less than 3%, particularly preferably less than 2%, and most particularly preferably less than 1%. This refers to the integrated reflectance in the spectral range from 380 nm to 780 nm, measured at an angle of 8° (to the surface normal) with illuminant type A at a "detection angle" of 2° (the 2° indicates the angle at which the light beam strikes the retina in the eye). To characterize the "detection angle," one usually speaks of a "2° detector."The integral reflectance is determined by recording a reflection spectrum at an angle of 8° (angle of incidence = angle of reflection = 8°), multiplying the reflection spectrum by the spectrum of the light source (illuminant A) and the eye sensitivity curve (for 2°, daytime vision) and then integrating it over the relevant spectral range (380 nm to 780 nm). The reflection spectrum is recorded with a measuring device without taking the light source used into account. For this purpose, a calibration is carried out, for example, whereby the measured value with the light source switched off corresponds to a value of 0 for all wavelengths and the measured value with the light source switched on corresponds to a value of 1 for all wavelengths. The reflection spectrum is then measured with the measuring device standardized or calibrated in this way, which then provides a standardized reflectance for each wavelength.The spectrum of illuminant A and the eye sensitivity curve, which are multiplied by the reflection spectrum, are standardized, with the maximum corresponding to a value of 1 in each case. The reflection of the IR-reflective coating itself can be determined by simulation or by measuring the reflection spectrum of the laminated pane with the IR-reflective coating and subtracting the reflection spectrum of a similar laminated pane without the IR-reflective coating. The reflection at any glass surface with a transition to air is approximately 4%.

[0018] A second solution according to the invention (solution B) is based on the inventors' finding that, during the typical introduction of insulation lines, the first dielectric layer or layer sequence remains completely or partially on the substrate surface. This is presumably due to the fact that the laser radiation is absorbed in particular by the silver layers, whereupon these silver layers and the layers above them are removed. Since the first dielectric layer or layer sequence has no silver layer underneath it, it remains (at least partially) unaffected by the laser processing. Consequently, for solution B, the inventors chose the approach of forming the IR-reflecting coating in such a way that it has the same or as similar a reflection color as possible to that of the first dielectric layer or layer sequence alone.The insulation lines then have (at least approximately) the same color as the rest of the coating, so that they are not visually noticeable.

[0019] The object of the invention is achieved according to solution B by a composite pane with the features mentioned at the outset, wherein the first silver layer and the third silver layer have a thickness which is at least 3 nm less than the thickness of the second silver layer, the optical thicknesses of the first dielectric layer or layer sequence and the fourth dielectric layer or layer sequence are less than the optical thicknesses of the second dielectric layer or layer sequence and the third dielectric layer or layer sequence, the optical thickness of the first dielectric layer or layer sequence is less than the optical thickness of the second dielectric layer or layer sequence. The reflection color of the first dielectric layer or layer sequence depends in particular on its optical thickness.According to the invention, the optical thickness of the first dielectric layer or layer sequence is from 35 nm to 85 nm in order to achieve adaptation of the reflection color to that of the coating.

[0020] The inventors have recognized that the desired matching of the reflection color of the first dielectric layer or layer sequence to the reflection color of the IR-reflecting coating can be achieved with a ranking of the optical thicknesses of the dielectric layers or layer sequences as specified above, if the thickness of the second silver layer is significantly greater than the thickness of the first and third silver layers and if the optical thickness of the first dielectric layer or layer sequence lies within the specified range. The introduction of insulation lines, with the first dielectric layer or layer sequence remaining completely or largely on the substrate, then does not lead to a significant change in the reflection color in the region of the insulation lines. The insulation line remains visually unobtrusive and does not attract the viewer's attention. This is the great advantage of the invention according to solution B.

[0021] A particularly good adaptation of its reflection color to the reflection color of the coating is achieved if the optical thickness of the first dielectric layer or layer sequence is from 45 nm to 75 nm, preferably from 55 nm to 65 nm, particularly preferably from 60 nm to 64 nm.

[0022] Particularly good results are achieved if, in addition, the optical thickness of the second dielectric layer or layer sequence is from 145 nm to 195 nm, preferably from 155 nm to 185 nm, particularly preferably from 165 nm to 175 nm, very particularly preferably from 165 nm to 170 nm, the optical thickness of the third dielectric layer or layer sequence is from 125 nm to 175 nm, preferably from 135 nm to 165 nm, particularly preferably from 145 nm to 155 nm, very particularly preferably from 149 nm to 153 nm, the optical thickness of the fourth dielectric layer or layer sequence (M4) is from 65 nm to 115 nm, preferably from 75 nm to 105 nm, particularly preferably from 85 nm to 95 nm, very particularly preferably from 88 nm to 92 nm.

[0023] The sum of the thicknesses of the silver layers is preferably from 20 nm to 40 nm, particularly preferably from 25 nm to 35 nm, most preferably from 28 nm to 32 nm. This achieves particularly good results with regard to the adaptation of the reflection color and a high transparency of the coating.

[0024] In an advantageous embodiment of the invention according to solution B, the thickness of the first silver layer is from 5 nm to 10 nm, preferably from 7 nm to 9 nm, particularly preferably from 8.0 nm to 8.5 nm, the thickness of the second silver layer is from 10 nm to 15 nm, preferably from 12 nm to 14 nm, particularly preferably from 12.5 nm to 13.0 nm, the thickness of the third silver layer is from 7 nm to 12 nm, preferably from 8 nm to 10 nm, particularly preferably from 9.0 nm to 9.5 nm.

[0025] In an advantageous embodiment of the invention according to solution B, the ratio of the optical thicknesses of the first dielectric layer or layer sequence to the optical thickness of the second and third dielectric layers or layer sequences is in each case from 0.2 to 0.6, preferably from 0.3 to 0.5, particularly preferably from 0.35 to 0.45, the ratio of the optical thickness of the fourth dielectric layer or layer sequence to the optical thickness of the second and third dielectric layers or layer sequences is in each case from 0.35 to 0.75, preferably from 0.45 to 0.65, particularly preferably from 0.5 to 0.6, the ratio of the optical thickness of the first dielectric layer or layer sequence to the optical thickness of the fourth dielectric layer or layer sequence is from 0.45 to 0.85, preferably from 0.55 to 0.75, particularly preferably from 0.6 to 0.7.

[0026] This achieves particularly good results with regard to adaptation of the reflection colors and coating and first dielectric layer(s).

[0027] The reflection colors a* and b* in the Lab color space of the IR-reflective coating preferably deviate from the reflection colors a* and b* of the first dielectric layer or layer sequence by less than 1, particularly preferably by less than 0.5. The reflection colors a* and b* are compared here, and the reflection colors b* are compared, whereby the values ​​for a* and b* can be and typically are quite different. The specified maximum deviation of the reflection colors preferably applies both to irradiation at an angle of 8° and to irradiation at an angle of 60°. The angle is measured to the surface normal. In this case, the inconspicuousness of any insulation lines is given regardless of the angle. The reflection colors are measured using the D65 light source and a "detection angle" of 10°.The "detection angle" indicates the angle at which the light beam hits the retina in the eye - the reflection colors are therefore determined taking into account the eye's sensitivity when the light hits the retina at an angle of less than 10° (ICT detector, 10° detector). The reflection colors of the first dielectric layer or layer sequence can be determined, in particular, through simulations or experiments.

[0028] The following explanations refer equally to both solution approaches (Solution A, Solution B).

[0029] Unless otherwise stated, the specification of layer thicknesses refers to the geometric thickness of a layer. If the optical thickness is meant instead, this is explicitly stated. The optical thickness, as defined by the invention, is the product of the geometric thickness and the refractive index at 550 nm.

[0030] A ratio of the (optical) thickness of a first layer to the (optical) thickness of a second layer is calculated as the quotient of the (optical) thickness of the first layer divided by the (optical) thickness of the second layer.

[0031] The composite pane according to the invention comprises an outer pane and an inner pane, which are bonded together via a thermoplastic intermediate layer. The composite pane is intended to separate the interior of a window opening, in particular the window opening of a vehicle, from the exterior environment. For the purposes of the invention, the "inner pane" refers to the pane of the composite pane facing the interior (in particular the vehicle interior). The "outer pane" refers to the pane facing the exterior environment.

[0032] The outer pane and the inner pane each have an outside surface and an inside surface and a circumferential side edge running between them. For the purposes of the invention, the term “outside surface” refers to the main surface which is intended to face the outside environment in the installed position. For the purposes of the invention, the term “inside surface” refers to the main surface which is intended to face the interior in the installed position. The inside surface of the outer pane and the outside surface of the inner pane face each other and the intermediate layer and are connected to one another by the thermoplastic intermediate layer. The outer pane and the inner pane are preferably made of glass, in particular soda-lime glass, which is common for window panes.In principle, the panes can also be made of other types of glass (e.g., borosilicate glass, quartz glass, aluminosilicate glass) or transparent plastics (e.g., polymethyl methacrylate or polycarbonate). The thickness of the outer pane and the inner pane can vary widely. Preferably, panes with a thickness in the range of 0.8 mm to 5 mm, preferably 1.2 mm to 3 mm, are used, for example, with the standard thicknesses of 1.6 mm or 2.1 mm.

[0033] The outer pane, the inner pane, and the thermoplastic interlayer can be clear and colorless, but also tinted or colored. The outer pane and the inner panes can independently be non-tempered, semi-tempered, or thermally or chemically toughened.

[0034] The thermoplastic intermediate layer contains at least one thermoplastic polymer, preferably polyvinyl butyral (PVB), ethylene-vinyl acetate (EVA), or polyurethane (PU), or mixtures or copolymers or derivatives thereof, particularly preferably PVB. The intermediate layer is typically formed from at least one thermoplastic film (bonding film), preferably based on one of the aforementioned polymers, in particular based on PVB. The thickness of the intermediate layer is preferably from 0.2 mm to 2 mm, particularly preferably from 0.5 mm to 1 mm.

[0035] If a polymeric film or layer is formed on the basis of a material, this means in the sense of the invention that the film or layer predominantly contains the said material (proportion of greater than 50 wt.%) and can optionally contain further components, for example plasticizers, stabilizers, UV or IR absorbers.

[0036] According to the invention, the composite pane is provided with an IR-reflective coating. The IR-reflective coating has reflective properties in the infrared spectral range (IR range), particularly in the near IR range. Such IR-reflective coatings are also referred to as solar control coatings. Their function is to reflect infrared components of solar radiation. The IR-reflective coating is, in particular, a transparent, electrically conductive coating. A transparent coating is understood to be a coating that has an average transmission in the visible spectral range of at least 70%, thus not significantly restricting visibility through the pane. Preferably, at least 80% of the base area of ​​the composite pane is provided with the solar control coating.In particular, the solar control coating is applied over the entire surface, with the exception of a surrounding edge area and optionally local areas that serve as communication, sensor, or camera windows to ensure the transmission of electromagnetic radiation through the laminated pane and are therefore not coated. The surrounding uncoated edge area, for example, has a width of up to 20 cm. It prevents direct contact of the IR-reflective coating with the surrounding atmosphere, thus protecting the coating inside the laminated pane from corrosion and damage.

[0037] The IR-reflective coating is a layer stack or layer sequence, in particular of thin layers, comprising a plurality of electrically conductive, in particular metal-containing, layers, wherein each electrically conductive layer is arranged between two dielectric layers or layer sequences. The coating is thus a thin-film stack with n electrically conductive layers and (n+1) dielectric layers or layer sequences, where n is a natural number, and wherein a lower dielectric layer or layer sequence is alternately followed by a conductive layer and a dielectric layer or layer sequence.

[0038] If a first layer is arranged above a second layer, this means, within the meaning of the invention, that the first layer is arranged further away from the substrate to which the coating is applied (outer pane or inner pane) than the second layer. If a first layer is arranged below a second layer, this means, within the meaning of the invention, that the second layer is arranged further away from the substrate than the first layer. If a first layer is arranged above or below a second layer, this does not necessarily mean, within the meaning of the invention, that the first and second layers are in direct contact with one another. One or more further layers can be arranged between the first and second layers, unless this is explicitly excluded.

[0039] The IR-reflective coating according to the invention has three electrically conductive layers. The said natural number n is therefore at least 3. The IR-reflective coating can have further electrically conductive layers and dielectric layers or layer sequences (n>3), in particular above the fourth dielectric layer or layer sequence. However, the IR-reflective coating preferably has exactly three electrically conductive layers and four dielectric layers or layer sequences (n=3). In a preferred embodiment, the IR-reflective coating consists of the layers or layer sequences mentioned above (silver layers and dielectric layers or layer sequences), whereby further metal-containing layers can optionally be present that do not contribute significantly to the electrical conductivity and IR-reflecting effect of the coating but serve a different purpose.This applies in particular to metallic blocker layers with geometric thicknesses of less than 1 nm, which are preferably arranged between the silver layers and the dielectric layer sequences located directly above and / or below them.

[0040] The silver layers impart the IR-reflective coating its IR-reflective properties and its electrical conductivity. Each silver layer is based on silver (Ag), meaning it consists essentially of silver apart from any doping or impurities. In an advantageous embodiment, each silver layer contains at least 90 wt.% silver, preferably at least 99 wt.% silver, particularly preferably at least 99.9 wt.% silver. The silver layers can contain doping agents, for example, palladium, gold, copper, or aluminum.

[0041] If a thin film is formed on the basis of a material, the layer consists predominantly of this material in addition to any impurities or dopants.

[0042] In addition to the silver layers, the dielectric layers or layer sequences influence the properties of the IR-reflecting coating, in particular its material or refractive index and its layer thickness. In a preferred embodiment, only dielectric layer sequences are present, so that between adjacent silver layers, as well as above the uppermost silver layer and below the lowermost silver layer, dielectric layer sequences consisting of a plurality of dielectric layers are present, rather than individual dielectric layers.

[0043] In a preferred embodiment of the invention, all dielectric layers present have a refractive index greater than 1.8, preferably greater than 1.9. In other words, all dielectric layers or layer sequences are formed exclusively from dielectric layers with a refractive index greater than 1.8. This achieves good results. The dielectric layers can, for example, be based on silicon nitride, silicon-metal mixed nitrides (such as silicon zirconium nitride (SiZrN), silicon-aluminum mixed nitride, silicon-hafnium mixed nitride or silicon-titanium mixed nitride), aluminum nitride (AlN), tin oxide (SnO), manganese oxide (MnO), tungsten oxide (WO3), niobium oxide (Nb205), bismuth oxide (Bi203), titanium oxide (TiCh), zinc oxide (ZnO) or tin-zinc mixed oxide (SnZnO).

[0044] The materials may contain dopants, particularly aluminum, boron, antimony, zirconium, or titanium. These dopants can provide dielectric materials with a certain degree of electrical conductivity. However, those skilled in the art will identify them as dielectric layers in terms of their function, as is common in the field of thin films. The material of the dielectric layers preferably has an electrical conductivity (the inverse of the resistivity) of less than 10' 4 S / m. The material of the electrically conductive layers preferably has an electrical conductivity of greater than 10 4 S / m on.

[0045] The oxides and nitrides mentioned in the present description can be deposited stoichiometrically, substoichiometrically or superstoichiometrically with regard to the oxygen or nitrogen content.

[0046] In the context of the present invention, the refractive index is given relative to a wavelength of 550 nm, unless explicitly stated otherwise. The refractive index is fundamentally independent of the measurement method. It can be determined, for example, using ellipsometry. Ellipsometers are commercially available, for example, from Sentech.

[0047] In an advantageous embodiment, each dielectric layer or layer sequence contains an anti-reflective coating. The anti-reflective coatings reduce the reflection of visible light and thus increase the transparency of the coated pane. The anti-reflective coatings are formed, for example, from silicon nitride (SiN), silicon-metal mixed nitrides such as silicon zirconium nitride (SiZrN), aluminum nitride (AlN), or tin oxide (SnO). The anti-reflective coatings can also contain doping. The anti-reflective coatings preferably have thicknesses of 10 nm to 100 nm, particularly preferably of 10 nm to 50 nm.

[0048] The anti-reflective coatings can in turn be divided into at least two sublayers, in particular into at least one dielectric layer with a refractive index of less than 2.1 and at least one optically highly refractive layer with a refractive index of greater than or equal to 2.1. Preferably, at least one anti-reflective coating arranged between two electrically conductive layers is divided in this way, particularly preferably all anti-reflective layers arranged between two electrically conductive layers, and most particularly preferably all anti-reflective layers. The subdivision of the anti-reflective coating leads to a lower sheet resistance of the IR-reflecting coating while simultaneously achieving high transmission and high color neutrality. The order of the sublayers can, in principle, be chosen arbitrarily.The thickness of the optically highly refractive layer is preferably from 10% to 99%, particularly preferably from 15% to 90% of the total thickness of the anti-reflective layer.

[0049] The optically high-index layer with a refractive index greater than or equal to 2.1 contains, for example, MnO, WO3, Nb2O5, Bi2O3, TiO2, ZrSiX, and / or AlN, preferably a silicon-metal mixed nitride, for example, silicon-hafnium mixed nitride (SiZrN) or silicon-titanium mixed nitride, particularly preferably silicon-zirconium mixed nitride (SiZrN). This is particularly advantageous with regard to the sheet resistance of the IR-reflecting coating. The silicon-zirconium mixed nitride preferably contains dopants, for example, aluminum. The proportion of zirconium (Zr) is preferably between 5 and 45 wt.%, particularly preferably between 10 and 30 wt.%. The refractive index of the optically high-index layer depends significantly on the Zr content.

[0050] The dielectric layer with a refractive index of less than 2.1 preferably has a refractive index between 1.6 and 2.1, particularly preferably between 1.9 and 2.1. The dielectric layer preferably contains at least one oxide, for example tin oxide, and / or a nitride, particularly preferably silicon nitride. The silicon nitride preferably has dopants, for example aluminum.

[0051] In an advantageous embodiment, one or more dielectric layer sequences comprise a first matching layer, preferably each dielectric layer sequence arranged beneath a silver layer. The first matching layer is preferably arranged above the anti-reflective layer. The first matching layer is preferably arranged directly beneath the silver layer, so that it has direct contact with the conductive layer. This is particularly advantageous with regard to the crystallinity of the electrically conductive layer. Optionally, however, a thin metallic blocking layer can be present between the silver layer and the first matching layer.

[0052] In an advantageous embodiment, one or more dielectric layer sequences have a smoothing layer, preferably each dielectric layer sequence arranged between two silver layers, particularly preferably additionally the bottommost dielectric layer sequence (first dielectric layer sequence). The smoothing layer is arranged below one of the first adaptation layers, preferably between the anti-reflective layer and the first adaptation layer, if such a first adaptation layer is present. The smoothing layer is particularly preferably in direct contact with the first adaptation layer. The smoothing layer optimizes, in particular smoothes, the surface for a silver layer subsequently applied above. A silver layer deposited on a smoother surface has a higher transmittance and, at the same time, a lower sheet resistance.The layer thickness of a smoothing layer is preferably from 5 nm to 15 nm, particularly preferably from 6 nm to 10 nm. The smoothing layer preferably has a refractive index of less than 2.2.

[0053] The smoothing layer preferably contains at least one non-crystalline oxide. The oxide can be amorphous or partially amorphous (and thus partially crystalline), but is not completely crystalline. The non-crystalline smoothing layer has low roughness and thus forms an advantageously smooth surface for the layers to be applied above the smoothing layer. The non-crystalline smoothing layer further effects an improved surface structure of the layer deposited directly above the smoothing layer, which is preferably the first adaptation layer. The smoothing layer can, for example, contain at least one oxide of one or more of the elements tin, silicon, titanium, zirconium, hafnium, zinc, gallium, and indium. The smoothing layer particularly preferably contains a non-crystalline mixed oxide. The smoothing layer very particularly preferably contains a tin-zinc mixed oxide (SnZnO). The mixed oxide preferably has dopants, for example antimony.The smoothing layer can, for example, contain an antimony-doped tin-zinc mixed oxide. The mixed oxide preferably has a substoichiometric oxygen content. The tin content is preferably between 10 and 40 wt.%, particularly preferably between 12 and 35 wt.%.

[0054] In an advantageous embodiment, one or more dielectric layer sequences comprise a second matching layer, preferably each dielectric layer sequence arranged above a silver layer. The second matching layer is preferably arranged below the anti-reflective layer.

[0055] The first and second matching layers improve the surface resistance of the coating. The first matching layer and / or the second matching layer preferably contains zinc oxide ZnOi-δ, where δ < δ < 0.01. The first matching layer and / or the second matching layer further preferably contains dopants, for example, aluminum. The zinc oxide is preferably deposited substoichiometrically with respect to oxygen in order to prevent a reaction of excess oxygen with the silver layer. The layer thicknesses of the first matching layer and the second matching layer are preferably from 5 nm to 15 nm, particularly preferably from 8 nm to 12 nm.

[0056] In an advantageous embodiment, the IR-reflecting coating comprises one or more blocker layers. Preferably, at least one blocker layer is assigned to at least one, particularly preferably each, silver layer. The blocker layer is in direct contact with the silver layer and is arranged directly above or directly below the silver layer. Therefore, no further layer is arranged between the silver layer and the blocker layer. A blocker layer can also be arranged directly above and directly below a silver layer. The blocker layer preferably contains niobium, titanium, nickel, chromium and / or alloys thereof, particularly preferably nickel-chromium alloys. The layer thickness of the blocker layer is preferably from 0.1 nm to 1 nm, particularly preferably from 0.1 nm to 0.5 nm.A blocking layer directly beneath the silver layer serves primarily to stabilize the silver layer during heat treatment and improves the optical quality of the IR-reflecting coating. A blocking layer directly above the silver layer prevents contact of the sensitive silver layer with the oxidizing reactive atmosphere during the deposition of the subsequent layer by reactive sputtering, for example, the second matching layer.

[0057] In a particularly advantageous embodiment of the invention according to solution A, the IR-reflecting coating comprises, in the specified order starting from the substrate surface (and preferably consists of): a first dielectric layer sequence with an optical thickness of 75 nm plus / minus (+ / -) 2 nm, in turn comprising (preferably consisting of): o an anti-reflection layer consisting of a single layer or several sub-layers based on SiN, SiZrN, SiHfN and / or SiTiN, o a smoothing layer based on SnZnO with a thickness of 8 nm + / - 2 nm, o a first adaptation layer based on ZnO with a thickness of 10 nm + / - 2 nm, a first silver layer with a thickness of 10 nm + / - 1 nm, preferably + / - 0.5 nm, a blocking layer based on NiCr or Ti with a thickness of 0.1 nm to 0.5 nm, a second dielectric layer sequence with an optical thickness of 140 nm plus / minus (+ / -) 2 nm,in turn comprising (preferably consisting of): o a second adaptation layer based on ZnO with a thickness of 10 nm + / - 2 nm, o an anti-reflection layer consisting of a single layer or several partial layers based on SiN, SiZrN, SiHfN and / or SiTiN, o a smoothing layer based on SnZnO with a thickness of 8 nm + / - 2 nm, o a first adaptation layer based on ZnO with a thickness of 10 nm + / - 2 nm, a second silver layer with a thickness of 10 nm + / - 1 nm, preferably + / - 0.5 nm, a blocking layer based on NiCr or Ti with a thickness of 0.1 nm to 0.5 nm, a third dielectric layer sequence with an optical thickness of 165 nm plus / minus (+ / -) 2 nm, in turn comprising (preferably consisting of): o a second adaptation layer based on ZnO with a thickness of 10 nm + / - 2 nm, o an anti-reflective coating consisting of a single layer or several sub-layers based on SiN, SiZrN, SiHfN and / or SiTiN,o a smoothing layer based on SnZnO with a thickness of 8 nm + / - 2 nm, o a first adaptation layer based on ZnO with a thickness of 10 nm + / - 2 nm, a third silver layer with a thickness of 10 nm + / - 1 nm, preferably + / - 0.5 nm, a blocking layer based on NiCr or Ti with a thickness of 0.1 nm to 0.5 nm, a fourth dielectric layer sequence with an optical thickness of 90 nm plus / minus (+ / -) 2 nm, in turn comprising (preferably consisting of): o a second adaptation layer based on ZnO with a thickness of 10 nm + / - 2 nm, o an anti-reflective layer consisting of a single layer or several sub-layers based on SiN, SiZrN, SiHfN and / or SiTiN.,

[0058] In a particularly advantageous embodiment of the invention according to solution B, the IR-reflecting coating comprises, in the specified order starting from the substrate surface (and preferably consists of): a first dielectric layer sequence with an optical thickness of 61 nm + / - 2 nm, in turn comprising (preferably consisting of): o an anti-reflection layer consisting of a single layer or several sub-layers based on SiN, SiZrN, SiHfN and / or SiTiN, o a smoothing layer based on SnZnO with a thickness of 8 nm + / - 2 nm, o a first adaptation layer based on ZnO with a thickness of 10 nm + / - 2 nm, a first silver layer with a thickness of 8 nm + / - 1 nm, preferably + / - 0.5 nm, a blocking layer based on NiCr or Ti with a thickness of 0.1 nm to 0.5 nm, a second dielectric layer sequence with an optical thickness of 167 nm plus / minus (+ / -) 2 nm,in turn comprising (preferably consisting of): o a second adaptation layer based on ZnO with a thickness of 10 nm + / - 2 nm, o an anti-reflective layer consisting of a single layer or several partial layers based on SiN, SiZrN, SiHfN and / or SiTiN, o a smoothing layer based on SnZnO with a thickness of 8 nm + / - 2 nm, o a first adaptation layer based on ZnO with a thickness of 10 nm + / - 2 nm, a second silver layer with a thickness of 13 nm + / - 1 nm, preferably + / - 0.5 nm, a blocking layer based on NiCr or Ti with a thickness of 0.1 nm to 0.5 nm, a third dielectric layer sequence with an optical thickness of 151 nm plus / minus (+ / -) 2 nm, in turn comprising (preferably consisting of): o a second adaptation layer based on ZnO with a thickness of 10 nm + / - 2 nm, o an anti-reflective coating consisting of a single layer or several sub-layers based on SiN, SiZrN, SiHfN and / or SiTiN,o a smoothing layer based on SnZnO with a thickness of 8 nm + / - 2 nm, o a first adaptation layer based on ZnO with a thickness of 10 nm + / - 2 nm, a third silver layer with a thickness of 9 nm + / - 1 nm, preferably + / - 0.5 nm, a blocking layer based on NiCr or Ti with a thickness of 0.1 nm to 0.5 nm, a fourth dielectric layer sequence with an optical thickness of 91 nm plus / minus (+ / -) 2 nm, in turn comprising (preferably consisting of): o a second adaptation layer based on ZnO with a thickness of 10 nm + / - 2 nm, o an anti-reflective layer consisting of a single layer or several sub-layers based on SiN, SiZrN, SiHfN and / or SiTiN. In both cases, all anti-reflective layers are preferably divided into at least two sub-layers, namely at least one dielectric layer based on SiN and at least one optically highly refractive layer based on SiZrN,SiHfN or SiTiN. The thickness of the anti-reflective coatings is selected so that – depending on the thickness of the smoothing and matching layers – the optical thickness of the respective dielectric layer sequence lies within the specified ranges.

[0059] The "plus / minus (+ / -)" values ​​indicate a thickness range or interval of possible thicknesses. A layer with a thickness of x + / - y nm has a thickness that lies in a range from (xy) nm to (x+y) nm.

[0060] The laminated pane is preferably curved in one or more directions of space, as is common for automotive windows, with typical radii of curvature ranging from approximately 10 cm to approximately 40 m. However, the laminated pane can also be flat, for example, if it is intended for building glazing or as a pane for buses, trains, or tractors.

[0061] The laminated pane has a transparent see-through area intended for viewing. The laminated pane can also have an opaque masking area. Such masking areas are common, for example, in vehicle windows (particularly windshields, rear windows, and roof windows). The masking area is arranged in a peripheral edge region and surrounds the central see-through area. The masking area is typically formed by an opaque masking print on a surface of the outer pane and / or the inner pane. The masking print is formed in particular from an enamel containing glass frits and a pigment, which is screen-printed and then fired into the pane surface. Alternatively, opaque films can also be used in the intermediate layer.The IR-reflective coating preferably completely covers the see-through area (except for any insulation lines) and extends into the masking area. Preferably, the side edge of the IR-reflective coating is positioned within the masking area so that it is not visible.

[0062] In an advantageous embodiment of the invention, the IR-reflecting coating has at least one insulation line. The insulation line is a linear region in which at least the silver layers have been removed (or chemically modified). The insulation line is intended, in particular, to enable the transmission of electromagnetic radiation, in particular high-frequency radiation, so that radio signals can pass through the laminated pane that would otherwise not be able to pass through the electrically conductive silver layers. The insulation line locally interrupts the electrical conductivity of the IR-reflecting coating. Typically, all dielectric layers or layer sequences arranged above at least one silver layer are also removed, i.e., the second, third, and fourth dielectric layers or layer sequences.The first dielectric layer or layer sequence can remain on the wafer. The insulation line is typically introduced into the IR-reflecting coating using laser radiation. The line width of the insulation line can, for example, be less than or equal to 500 pm. In a preferred embodiment of the invention, the line width is from 10 pm to 300 pm, particularly preferably from 50 pm to 200 pm.

[0063] In such a coating with an insulation line, the advantages of the invention are particularly evident, since it is designed so that the insulation line is visually particularly unobtrusive.

[0064] To transmit RF radiation, the IR-reflective coating is typically provided with a plurality of insulation lines, which are arranged parallel to one another, for example, or in a grid-like pattern covering part or all of the coating. The grid can, for example, extend across the entire view-through area of ​​the laminated pane.

[0065] The laminated glass (or its viewing area) preferably has a total transmittance (light transmittance) of greater than 70%. The term "total transmittance" refers to the procedure for testing the light transmittance of motor vehicle windows specified in ECE-R 43, Annex 3, Section 9.1.

[0066] The invention also includes a method for producing a composite pane according to the invention, wherein in the specified order

[0067] (a) the outer pane and the inner pane are provided,

[0068] (b) a surface of the outer pane or the inner pane is provided with the IR-reflecting coating,

[0069] (c) the outer pane and the inner pane are bonded to one another via the thermoplastic intermediate layer, with said surface facing the intermediate layer. The IR-reflecting coating is typically applied from the gas phase (gas phase deposition). The IR-reflecting coating is preferably applied to said surface by physical vapor deposition (PVD), particularly preferably by cathode sputtering, and most preferably by magnetic field-assisted cathode sputtering (magnetron sputtering). In principle, however, the coating can also be applied, for example, by chemical vapor deposition (CVD), for example plasma-enhanced vapor deposition (PECVD), by vapor deposition, or by atomic layer deposition (ALD).

[0070] If the composite pane is to be curved, the outer pane and the inner pane are subjected to a bending process, preferably before lamination in process step (c) and preferably after coating in process step (b). The outer pane and the inner pane are preferably bent congruently while lying on top of one another (i.e., simultaneously and using the same tool), as this ensures that the shape of the panes is optimally matched for subsequent lamination. Typical temperatures for glass bending processes are, for example, 500°C to 700°C. All standard bending methods can be used, for example, gravity bending, press bending, and / or suction bending.

[0071] The coating is preferably subjected to a heat treatment, particularly preferably at least 300°C. This heat treatment increases the transparency and reduces the sheet resistance of the IR-reflective coating. The heat treatment can be performed during a bending process, during which the coated pane is already subjected to considerable heat.

[0072] In an advantageous embodiment, at least one insulation line is introduced into the IR-reflecting coating by means of laser radiation. The laser radiation is moved along a line across the coating, removing (or chemically modifying) the silver layers, so that the electrically insulating insulation line is introduced into the coating. Preferably, those dielectric layers or layer sequences located above at least one silver layer are also removed. The bottom (first) dielectric layer or layer sequence can remain completely or partially on the surface of the pane, which is also preferred, at least when producing a composite pane according to solution B. The insulation line is preferably introduced before lamination of the composite pane in process step (c).

[0073] The inventors have discovered that the introduction of the insulation line is particularly efficient and the IR-reflecting coating is severed with particularly good insulation when the laser radiation is directed through the pane (outer or inner pane) provided with the IR-reflecting coating onto the IR-reflecting coating. The laser radiation thus first strikes the surface facing away from the coating, passes through the pane, and then strikes the IR-reflecting coating. In other words, the laser radiation is directed through said pane onto the IR-reflecting coating.

[0074] Laser radiation in the ultraviolet (preferably from 200 nm to 400 nm), visible, or infrared (preferably from 800 nm to 1200 nm) spectral range can be used. For example, Nd:YAG lasers with an emission wavelength of 1064 nm are suitable. The laser is preferably operated in pulsed mode, particularly preferably with pulse lengths in the femtosecond range, for example, less than or equal to 800 fs. The laser is preferably focused on the IR-reflecting coating, for example using a lens or objective. The laser is then moved over the coating, for example using a laser scanner, to introduce the insulation line. The movement speed is preferably selected such that adjacent pulses impinging on the coating spatially overlap one another, with the overlap area preferably corresponding to at least 50% of the focus size, particularly preferably at least 80%.

[0075] The bonding of the outer pane and inner pane in process step (c) is carried out using conventional methods. The outer pane and the inner pane are laminated together via the intermediate layer, for example, using autoclave processes, vacuum bag processes, vacuum ring processes, calender processes, vacuum laminators, or combinations thereof. The bonding of the outer pane and inner pane is usually achieved under the influence of heat, vacuum, and / or pressure.

[0076] The invention further encompasses the use of a composite pane according to the invention in a vehicle on land, water, or in the air, preferably a motor vehicle, rail vehicle, aircraft, or ship, in particular a passenger car or truck. The composite pane is preferably used as a vehicle pane, particularly preferably as a window pane of a passenger car or truck. The composite pane is, for example, a windshield, rear window, side window, or roof pane, preferably a windshield or roof pane.

[0077] The invention is explained in more detail below with reference to a drawing and exemplary embodiments. The drawing is a schematic representation and not to scale. The drawing does not limit the invention in any way.

[0078] They show:

[0079] Fig. 1 is a plan view of a composite pane according to the invention,

[0080] Fig. 2 shows a cross section through the composite pane from Figure 1,

[0081] Fig. 3 shows a cross section through an IR-reflecting coating according to the invention on an inner pane.

[0082] Figures 1 and 2 each show a detail of a composite pane according to the invention, which is the windshield of a passenger car. The composite pane is constructed of an outer pane 1 and an inner pane 2, which are bonded together via a thermoplastic intermediate layer 3. In the installed position, the outer pane 1 faces the outside environment, while the inner pane 2 faces the vehicle interior.

[0083] The outer pane 1 has an outer surface I which, in the installed position, faces the outside environment, and an inner surface II which, in the installed position, faces the interior space. Likewise, the inner pane 2 has an outer surface III which, in the installed position, faces the outside environment, and an inner surface IV which, in the installed position, faces the interior space. The outer pane 1 and the inner pane 2 are made, for example, of soda-lime glass. The outer pane 1 has, for example, a thickness of 2.1 mm, the inner pane 2 a thickness of 1.6 mm. The intermediate layer 3 is made, for example, of a PVB film with a thickness of 0.76 mm.

[0084] The composite pane is provided with an IR-reflective coating 20, which is applied to the outer surface III of the inner pane 2. The IR-reflective coating 20 is intended to reflect infrared components of solar radiation and thereby improve thermal comfort in the vehicle interior. The IR-reflective coating 20 is a thin-film stack with three silver layers, each arranged between two dielectric layer sequences.

[0085] The silver-containing IR-reflective coating 20 has the disadvantage that it is impermeable to high-frequency electromagnetic radiation. As a result, GPS signals or mobile phone signals, for example, cannot penetrate the composite pane. To ensure RF transmission, the coating 20 is provided with insulation lines 5 arranged in a grid, as can be seen in the enlarged section of Figure 1.

[0086] The interior-facing surface II of the outer pane 1 is provided with a black masking print 4 along its peripheral edge, forming an opaque masking area. The masking area surrounds a central transparent see-through area of ​​the composite pane in a frame-like manner. The IR-reflective coating 20 does not extend to the side edge of the composite pane—its edge is located in said masking area. The IR-reflective coating 20 has no contact with the surrounding atmosphere, thus protecting the corrosion-prone silver layers.

[0087] Figure 3 shows the layer sequence of an embodiment according to the invention of the IR-reflecting coating 20 on the inner pane 2. The IR-reflecting coating 20 comprises four dielectric layer sequences M1, M2, M3, M4 and three silver layers 21.1,

[0088] 21.2, 21.3, which are arranged alternately. Between each silver layer 21.1, 21.2, 21.3 and the overlying dielectric layer sequence M1, M2, M3, M4, a thin blocking layer 26.1, 26.2, 26.3 is arranged.

[0089] The first dielectric layer sequence M1 is composed of an anti-reflection layer 22.1, a smoothing layer 23.1 and a first adaptation layer 24.1.

[0090] The second dielectric layer sequence M2 is composed of a second adaptation layer 25.2, an anti-reflection layer 22.2, a smoothing layer 23.2 and a first adaptation layer 24.2.

[0091] The third dielectric layer sequence M3 is composed of a second adaptation layer

[0092] 25.3, an anti-reflective layer 22.3, a smoothing layer 23.3 and a first adjustment layer 24.3.

[0093] The fourth dielectric layer sequence M4 is composed of a second adaptation layer

[0094] 25.4 and an anti-reflective coating 22.4. The anti-reflective coatings 22.1, 22.2, 22.3, and 22.4 are each divided into several individual layers. The first anti-reflective layer 22.1, the third anti-reflective layer 22.3, and the fourth anti-reflective layer 22.4 are each divided into two individual layers, namely a dielectric layer 22a.1, 22a.3, 22a.4 with a refractive index of less than 2.1 and an optically highly refractive layer 22b.1, 22b.3, 22b.4 with a refractive index of greater than 2.1. The second anti-reflection layer 22.2 is divided into an optically high-refractive layer 22b.2 with a refractive index greater than 2.1, an optically high-refractive layer 22c.2 with a refractive index greater than 2.3, a dielectric layer 22a.2 with a refractive index less than 2.1 and a further optically high-refractive layer 22d.2 with a refractive index greater than 2.1.

[0095] The layer sequence is shown schematically in the figure. The layer sequence of a composite pane with the IR-reflecting coating 20 on the outer surface III of the inner pane 2 is shown in Table 1, along with the materials and layer thicknesses of the individual layers, for two examples 1 and 2 according to the invention and a non-inventive comparative example.

[0096] The comparative example basically has the same layer sequence as examples 1 and 2, with the anti-reflection layers 22.1, 22.2, 22.3, 22.4 (and their sub-layers 22a.1, 22a.2, 22a.3; 22a.4, 22b.1, 22b.2, 22b.3, 22b.4; 22c.2; 22d.2), the smoothing layer 23.1, 23.2, 23.3, the first adjustment layer 24.1, 24.2, 24.3, the second adjustment layer 25.2, 25.3, 25.4, the blocking layers 26.1, 26.2, 26.3 and the silver layers 21.1, 21.2, 21.3. The same materials are used, whereby the comparative example differs from the inventive examples 1 and 2 only in the layer thicknesses.

[0097] Table 1 The silver layers 21.1, 21.2, 21.3 are based on silver (Ag), the blocking layers 26.1, 26.2, 26.3 are based on a nickel-chromium alloy (NiCr), the smoothing layer 23.1, 23.2, 23.3 are based on tin-zinc mixed oxide (SnZnO), the first matching layers 24.1, 24.2, 24.3 and the second matching layers 25.2, 25.3, 25.4 are based on zinc oxide (ZnO), the dielectric layers 22a.1, 22a.2, 22a.3, 22a.4 with a refractive index of less than 2.1 are based on silicon nitride (SiN), the optically high-refractive layers 22b.1, 22b.2, 22b.3, 22b.4, 22d.2 with a refractive index greater than 2.1 based on a silicon-zirconium mixed nitride deposited in a nitrogen atmosphere with argon addition with a silicon-zirconium target with a zirconium content of 17 wt.% (SiZr17N) and the optically highly refractive layer 22c.2 with a refractive index greater than 2.3 based on a silicon-zirconium mixed nitride, which was deposited in a nitrogen atmosphere with added argon using a silicon-zirconium target with a zirconium content of 27 wt.% (SiZr27N). The oxides and nitrides can be deposited stoichiometrically, substoichiometrically, or superstoichiometrically with regard to the oxygen or nitrogen content, which is why a stoichiometric molecular formula was omitted. In the examples and the comparative example, however, the same stoichiometric ratio was chosen for layers based on the same material. The layers can also contain dopants and impurities. The doping for layers based on the same material was also the same in the examples and the comparative example. For example, layers based on SnZnO can be doped with antimony, and layers based on ZnO, SiN, or SiZrN can be doped with aluminum.

[0098] The dielectric layers have the following refractive indices at 550 nm: ZnO (2.00), SiN (2.00), SnZnO (2.05), SiZr17N (2.22), SiZr27N (2.40).

[0099] The optical thicknesses of the individual dielectric layers correspond to the product of the geometric thickness specified in the tables and the refractive index. The optical thicknesses of the entire dielectric layer sequences M1, M2, M3, M4 correspond to the sum of the optical thicknesses of the individual layers. The optical thicknesses of the dielectric layer sequences M1, M2, M3, M4 for Examples 1 and 2 and the comparative example are summarized in Table 2. Table 2

[0100] Composite panes were produced, which were designed similarly according to Figures 1 and 2, with the IR-reflective coatings 20 of Examples 1 and 2 and the Comparative Example. The IR-reflective coatings 20 were each provided with insulation lines 5 using laser radiation and visually inspected. In the Comparative Example, the insulation lines 5 were visually very noticeable, whereas in Examples 1 and 2 they were significantly less clearly visible.

[0101] The conspicuousness of the insulation lines 5 in the comparative example is due to the fact that the insulation lines 5 exhibit a significantly different reflection behavior than the remaining coating 20, in particular a significantly different reflection color. Within the scope of the invention, two approaches were pursued to reduce the conspicuousness of the insulation lines 5.

[0102] A first solution according to the invention (solution A) is based on the approach of designing the IR-reflective coating in such a way that it has only very low reflection in the visible spectral range. The coating is therefore also color-neutral, so that the insulation lines do not lead to visually noticeable color changes. This solution was implemented in example 2. The integrated light reflection of the coating 20 alone, adjusted for the reflection contributions of the glass surfaces, is only 0.8% in example 2, while it is 3.5% in the comparative example. The integrated light reflection is determined using a standard light source A in the spectral range from 380 nm to 780 nm at an angle of 8° (angle of incidence and reflection of the radiation, relative to the surface normal) with a 2° detector (i.e., taking into account the eye sensitivity curve when the light hits the retina at an angle of 2°).

[0103] The low reflection of Example 2 is achieved in particular in that the silver layers 21.1, 21.2, 21.3 have the same thickness, that the optical thickness of the first dielectric layer sequence M1 is less than the optical thickness of the fourth dielectric layer sequence M4, that the optical thickness of the fourth dielectric layer sequence M4 is less than the optical thickness of the second dielectric layer sequence M2 and that the optical thickness of the second dielectric layer sequence M2 is less than the optical thickness of the third dielectric layer sequence M3.

[0104] The mean thickness of the silver layers 21.1, 21.2, and 21.3 in Example 2 was 10 nm, and the thicknesses of all silver layers 21.1, 21.2, and 21.3 deviate from this mean by 0%. The mean thickness of the silver layers 21.1, 21.2, and 21.3 in the comparative example was 11 nm, and the thicknesses of the silver layers 21.1, 21.2, and 21.3 deviate from this mean by 1.8%, 7.3%, and 9.1%, respectively.The ratios of the optical thicknesses of the above-mentioned dielectric layer sequences are summarized in Table 3, namely the ratio of the optical thickness of the first dielectric layer sequence M1 to the optical thickness of the fourth dielectric layer sequence M4 (“M1 / M4”), the ratio of the optical thickness of the fourth dielectric layer sequence M4 to the optical thickness of the second dielectric layer sequence M2 (“M4 / M2”), the ratio of the optical thickness of the second dielectric layer sequence M2 to the optical thickness of the third dielectric layer sequence M3 (“M2 / M3”).

[0105] Table 3

[0106] A second solution according to the invention (solution B) utilizes the inventors' finding that when the insulation lines 5 are produced by means of laser radiation, the first dielectric layer sequence M1 typically remains completely or at least largely on the glass surface. According to solution B, the reflection color of the first dielectric layer sequence M1 is adapted to the reflection color of the entire coating 20. This solution was implemented in example 1. The reflection colors in the Lab color space were a*=(-1,2) and b*=(-4,6) for the coating 20 and the first dielectric layer sequence M1 when irradiated at an angle of 8° and for a*=(-1,0) and b*=(-2,2) when irradiated at an angle of 60°. The color values ​​were determined using a standard D65 light source and a 10° detector.

[0107] The adaptation of the reflection colour of the insulation lines 5 to that of the coating 20 in Example 1 is achieved in particular by

[0108] - the second silver layer 21.2 has a significantly greater thickness than the first silver layer 21.1 and the third silver layer 21.3,

[0109] - the optical thicknesses of the first dielectric layer sequence M1 and the fourth dielectric layer sequence M4 are smaller than the optical thicknesses of the second dielectric layer sequence M2 and the third dielectric layer sequence M3,

[0110] - the optical thickness of the first dielectric layer sequence M1 is less than the optical thickness of the second dielectric layer or layer sequence M2,

[0111] - the optical thickness of the first dielectric layer sequence M1 is from 35 nm to 85 nm.

[0112] The ratios of the optical thicknesses of the above-mentioned dielectric layer sequences are summarized in Table 4, namely the ratio of the optical thickness of the first dielectric layer sequence M1 to the optical thickness of the second dielectric layer sequence M2 (“M1 / M2”), the ratio of the optical thickness of the first dielectric layer sequence M1 to the optical thickness of the third dielectric layer sequence M3 (“M1 / M3”), the ratio of the optical thickness of the fourth dielectric layer sequence M4 to the optical thickness of the second dielectric layer sequence M2 (“M4 / M2”), the ratio of the optical thickness of the fourth dielectric layer sequence M4 to the optical thickness of the third dielectric layer sequence M3 (“M4 / M3”), the ratio of the optical thickness of the first dielectric layer sequence M1 to the optical thickness of the fourth dielectric layer sequence M4 (“M1 / M4”).

[0113] Table 4 List of reference symbols:

[0114] (1) Outer pane

[0115] (2) Inner pane

[0116] (3) thermoplastic intermediate layer

[0117] (4) Cover printing

[0118] (5) Insulation line

[0119] (20) IR-reflective coating

[0120] (M1), (M2), (M3), (M4) 1st, 2nd, 3rd, 4th dielectric layer sequence

[0121] (21.1), (21.2), (21.3) 1st, 2nd, 3rd silver layer

[0122] (22.1), (22.2), (22.3), (22.4) 1st, 2nd, 3rd, 4th anti-reflective coating

[0123] (22a.1), (22a.2), (22a.3), (22a.4) 1st, 2nd, 3rd, 4th dielectric layer (refractive index < 2.1)

[0124] (22b.1), (22b.2), (22b.3), (22b.4) 1st, 2nd, 3rd, 4th optically highly refractive layer

[0125] (Refractive index > 2.1)

[0126] (22C.2) optically highly refractive layer (refractive index > 2.3)

[0127] (22d.2) additional optically highly refractive layer (refractive index > 2.1)

[0128] (23.1), (23.2), (23.3) 1st, 2nd, 3rd smoothing layer

[0129] (24.1), (24.2), (24.3) 1.. 2.. 3. first adaptation layer

[0130] (25.2), (25.3), (25.4) 1.. 2., 3. second adaptation layer

[0131] (26.1), (26.2), (26.3) 1.. 2.. 3. Blocker layer

[0132] (I) outside surface of the outer pane 1

[0133] (II) interior surface of the outer pane 1

[0134] (III) outer surface of the inner pane 2

[0135] (IV) interior surface of the inner pane 2

Claims

Patent claims 1. A composite pane with an IR-reflecting coating (20), comprising - an outer pane (1) and an inner pane (2) which are connected to one another via a thermoplastic intermediate layer (3), - an IR-reflecting coating (20) on the surface (II, III) of the outer pane (1) or the inner pane (2) facing the intermediate layer (3), wherein the IR-reflecting coating (20) comprises, starting from said surface (II, III), in the specified order: - a first dielectric layer or layer sequence (M1), - a first silver layer (21.1), - a second dielectric layer or layer sequence (M2), - a second silver layer (21.2), - a third dielectric layer or layer sequence (M3), - a third silver layer (21.3), - a fourth dielectric layer or layer sequence (M4), wherein - each silver layer (21.1, 21.2, 21.3) has a thickness which deviates by no more than 5% from the average thickness of all silver layers (21.1, 21.2, 21.3), - the optical thickness of the first dielectric layer or layer sequence (M1) is less than the optical thickness of the fourth dielectric layer or layer sequence (M4), - the optical thickness of the fourth dielectric layer or layer sequence (M4) is less than the optical thickness of the second dielectric layer or layer sequence (M2), - the optical thickness of the second dielectric layer or layer sequence (M2) is less than the optical thickness of the third dielectric layer or layer sequence (M3).

2. Composite pane according to claim 1, wherein - the ratio of the optical thickness of the first dielectric layer or layer sequence (M1) to the optical thickness of the fourth dielectric layer or layer sequence (M4) is from 0.7 to 0.95, preferably from 0.8 to 0.9, - the ratio of the optical thickness of the fourth dielectric layer or layer sequence (M4) to the optical thickness of the second dielectric layer or layer sequence (M2) is from 0.5 to 0.8, preferably from 0.6 to 0.7, the ratio of the optical thickness of the second dielectric layer or layer sequence (M2) to the optical thickness of the third dielectric layer or layer sequence (M3) is from 0.7 to 0.95, preferably from 0.8 to 0.

9.

3. Composite pane according to claim 1 or 2, wherein - the optical thickness of the first dielectric layer or layer sequence (M1) is from 50 nm to 100 nm, preferably from 60 nm to 90 nm, particularly preferably from 70 nm to 80 nm, very particularly preferably from 73 nm to 77 nm, - the optical thickness of the second dielectric layer or layer sequence (M2) is from 115 nm to 165 nm, preferably from 125 nm to 155 nm, particularly preferably from 135 nm to 145 nm, very particularly preferably from 138 nm to 142 nm, - the optical thickness of the third dielectric layer or layer sequence (M3) is from 140 nm to 190 nm, preferably from 150 nm to 180 nm, particularly preferably from 160 nm to 170 nm, very particularly preferably from 163 nm to 167 nm, - the optical thickness of the fourth dielectric layer or layer sequence (M4) is from 65 nm to 115 nm, preferably from 75 nm to 105 nm, particularly preferably from 85 nm to 95 nm, very particularly preferably from 88 nm to 92 nm.

4. Composite pane according to one of claims 1 to 3, wherein the thickness of all silver layers (21.1, 21.2, 21.3) is each from 10 nm to 11 nm.

5. Composite pane according to one of claims 1 to 4, wherein the IR-reflecting coating (20) has a reflection of less than 3%, preferably less than 2%, determined as integrated reflectance in the spectral range from 380 nm to 780 nm, measured at an angle of 8° with illuminant A and a 2° detector.

6. Composite pane with an IR-reflecting coating (20), comprising - an outer pane (1) and an inner pane (2) which are connected to one another via a thermoplastic intermediate layer (3), - an IR-reflecting coating (20) on the surface (II, III) of the outer pane (1) or the inner pane (2) facing the intermediate layer (3), wherein the IR-reflecting coating (20) comprises, starting from said surface (II, III), in the specified order: - a first dielectric layer or layer sequence (M1), - a first silver layer (21.1), - a second dielectric layer or layer sequence (M2), - a second silver layer (21.2), - a third dielectric layer or layer sequence (M3), - a third silver layer (21.3), - a fourth dielectric layer or layer sequence (M4), wherein - the first silver layer (21.1) and the third silver layer (21.3) have a thickness which is at least 3 nm less than the thickness of the second silver layer (21.2), - the optical thicknesses of the first dielectric layer or layer sequence (M1) and the fourth dielectric layer or layer sequence (M4) are less than the optical thicknesses of the second dielectric layer or layer sequence (M2) and the third dielectric layer or layer sequence (M3), - the optical thickness of the first dielectric layer or layer sequence (M1) is less than the optical thickness of the second dielectric layer or layer sequence (M2), - the optical thickness of the first dielectric layer or layer sequence (M1) is from 35 nm to 85 nm.

7. Composite pane according to claim 6, wherein - the ratio of the optical thicknesses of the first dielectric layer or layer sequence (M1) to the optical thickness of the second dielectric layer or layer sequence (M2) and the third dielectric layer or layer sequence (M3) is in each case from 0.3 to 0.5, preferably from 0.35 to 0.45, - the ratio of the optical thickness of the fourth dielectric layer or layer sequence (M4) to the optical thickness of the second dielectric layer or layer sequence (M2) and the third dielectric layer or layer sequence (M3) is in each case from 0.45 to 0.65, preferably from 0.5 to 0.6, - the ratio of the optical thickness of the first dielectric layer or layer sequence (M1) to the optical thickness of the fourth dielectric layer or layer sequence (M4) is from 0.55 to 0.75, preferably from 0.6 to 0.

7.

8. Composite pane according to claim 6 or 7, wherein - the optical thickness of the first dielectric layer or layer sequence (M1) is from 35 nm to 85 nm, preferably from 45 nm to 75 nm, particularly preferably from 55 nm to 65 nm, very particularly preferably from 60 nm to 64 nm, - the optical thickness of the second dielectric layer or layer sequence (M2) is from 145 nm to 195 nm, preferably from 155 nm to 185 nm, particularly preferably from 165 nm to 175 nm, very particularly preferably from 165 nm to 170 nm, - the optical thickness of the third dielectric layer or layer sequence (M3) is from 125 nm to 175 nm, preferably from 135 nm to 165 nm, particularly preferably from 145 nm to 155 nm, very particularly preferably from 149 nm to 153 nm, - the optical thickness of the fourth dielectric layer or layer sequence (M4) is from 65 nm to 115 nm, preferably from 75 nm to 105 nm, particularly preferably from 85 nm to 95 nm, very particularly preferably from 88 nm to 92 nm.

9. Composite pane according to one of claims 6 to 8, wherein the sum of the thicknesses of the silver layers (21.1, 21.2, 21.3) is from 20 nm to 40 nm, preferably from 25 nm to 35 nm, particularly preferably from 28 nm to 32 nm, and wherein very particularly preferably - the thickness of the first silver layer is from 7 nm to 9 nm, most preferably from 8.0 nm to 8.5 nm, - the thickness of the second silver layer is from 12 nm to 14 nm, most preferably from 12.5 nm to 13.0 nm, - the thickness of the third silver layer is from 8 nm to 10 nm, most preferably from 9.0 nm to 9.5 nm.

10. Composite pane according to one of claims 6 to 9, wherein the reflection colors a* and b* in the Lab color space of the IR-reflecting coating (20) and the first dielectric layer or layer sequence (M1) differ from one another by less than 1, preferably by less than 0.5, both when irradiated at an angle of 8° and when irradiated at an angle of 60° relative to the surface normal, measured with the light source D65 and a 10° detector.

11. Composite pane according to one of claims 1 to 10, wherein the IR-reflecting coating (20) has at least one insulation line (5).

12. Composite pane according to one of claims 11, which has a transparent see-through area and an opaque masking area, wherein the IR-reflecting coating (20) is provided with a grid of insulation lines (5) which extends over the entire see-through area.

13. A method for producing a composite pane according to any one of claims 1 to 12, wherein (d) the outer pane (1) and the inner pane (2) are provided, (e) a surface (II, III) of the outer pane (1) or the inner pane (2) is provided with the IR-reflecting coating (20), (f) the outer pane (1) and the inner pane (2) are joined together via the thermoplastic intermediate layer (3), wherein said surface (II, III) faces the intermediate layer (3).

14. The method according to claim 13, wherein at least one insulation line (5) is introduced into the IR-reflecting coating (20) by means of laser radiation directed through the outer pane (1) or inner pane (2) provided with the IR-reflecting coating (20) onto the IR-reflecting coating (20).

15. Use of a composite pane according to one of claims 1 to 12 as a vehicle pane, in particular as a windscreen or roof pane.

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