Composite glass pane with a solar protection coating

Abstract

Composite glass pane (100) comprising an outer glass pane (1) having an outer side surface (I) and an inner side surface (II), an inner glass pane (2) having an outer side surface (III) and an inner side surface (IV) and a thermoplastic intermediate layer (3) which joins the inner side surface (II) of the outer glass pane (1) with the outer side surface (III) of the inner glass pane (2), wherein the composite glass pane (100) has at least one solar protection coating (4) between the outer glass pane (1) and the inner glass pane (2), wherein the solar protection coating (4) comprises the following layer sequence in the direction from the inner glass pane (2) towards the outer glass pane (1): - a first dielectric module (M1), - a first silver layer (Ag1), - a second dielectric module (M2), - a second silver layer (Ag2), - a third dielectric module (M3), - a third silver layer (Ag3), - a fourth dielectric module (M4), wherein the silver layers (Ag1, Ag2, Ag3) have a relative geometric layer thickness between one another of Ag2 > Ag1 > Ag3, and the silver layers (Ag1, Ag2, Ag3) of the solar protection coating have a relative geometric layer thickness of 1.0 < Ag1 / Ag3 and 1.2 < Ag2 / Ag3 < 2.

Description

TECHNICAL FIELD

[0001] The present invention relates to a composite glass pane with an improved solar protection coating and the use thereof. BACKGROUND

[0002] Composite glass panes with an electrically conductive coating are well known in the field of vehicles, for example as windscreen panes with a heatable transparent coating. The coating usually comprises a plurality of silver layers applied alternately with dielectric layers, thereby ensuring on the one hand a high electrical conductivity and on the other hand a sufficient transmission in the visible spectral range. More complex electrically conductive coatings for windscreen panes are also known, which for example serve as IR-reflective coatings to reduce the warming of the interior space of the vehicle and thereby to improve the thermal comfort. However, the coatings can also serve as heatable coatings, which by connecting them with a voltage source, cause an electric current to flow through the coating. Suitable coatings comprise electrically conductive metal layers, which are based in particular on silver. Since these layers are susceptible to corrosion, they are usually applied on the surface of the outer or inner glass pane facing the interlayer, so that they are not in contact with the atmosphere. Silver-containing transparent coatings are known for example from WO 03 / 024155, US 2007 / 0082219 A1, US 2007 / 0020465 A1, WO 2013 / 104438 or WO 2013 / 104439.

[0003] It is pursued especially in the automotive field that the solar protection coating is not only heatable, but also has a low total solar energy transmittance (TTS), a low external reflectance and a neutral or blue reflection color. Especially yellow, red and violet reflection colors are considered disturbing and should be avoided. Good solar protection properties of the vehicle glass also contribute to a reduction of the energy consumption of the air conditioning device and are therefore pursued from an environmental point of view as well. In electric vehicles, a reduction of the energy consumption of secondary systems such as air conditioning and heating means an increase of the range. In electric vehicles, a direct current voltage converter, also called DC / DC converter, is usually used, which increases the vehicle voltage of 14 V to a supply voltage of 42 V, through which the heatable windscreen pane is operated. Heatable solar protection coatings developed for motor vehicles with internal combustion engines are usually designed to a supply voltage of 14 V and are not compatible with the operating range of 14 V / 42 V direct current voltage converters. In this respect, merely increasing the layer thickness of the known heatable solar protection coatings designed for use with a supply voltage of 14 V is not successful in order to reduce the total solar energy transmittance (TTS). A low total solar energy transmittance (TTS) is usually accompanied by a high external reflectance of the coating, but in fact as small an absolute value of both variables as possible is desirable. Furthermore, for windscreen panes the legal regulations according to the motor vehicle glass pane light transmission test method according to ECE-R 43, appendix 3, section 9.1 apply, according to which the total transmittance T LIt must be at least 70%. This makes achieving a low total solar transmittance even more challenging. High demands are placed on the optical and electrical properties of the sunscreen coating if it is to be used as a heat-resistant coating in the automotive field, have a visually appealing reflective color, and be compatible with the DC-DC voltage converters commonly used in electric vehicles.

[0004] WO2019 / 206493A1 discloses a composite glass plate for a head-up display, at least one conductive coating on one of the surfaces of the outer or inner glass plate of the composite glass plate facing a thermoplastic interlayer, and an anti-reflective coating on the surface of the inner glass plate facing away from the thermoplastic interlayer. The conductive coating comprises at least four conductive silver layers with a total thickness of at least 60 nm, wherein dielectric layers are disposed between the silver layers. Viewed from the inner glass plate toward the outer glass plate, the third silver layer following the inner glass plate is the thickest silver layer.

[0005] WO2020 / 094422A1 relates to a projection device for a head-up display (HUD), comprising at least a composite glass plate having a HUD area, a conductive coating on a surface of an outer or inner glass plate facing a thermoplastic interlayer, and a projector. The conductive coating comprises at least four conductive layers disposed between two dielectric layers, wherein the total thickness of all conductive layers is at most 30 nm, and wherein at least one of these conductive layers has a thickness of at most 5 nm.

[0006] WO 2020 / 094423A1 describes a projection device for a head-up display (HUD) comprising a composite glass plate having a conductive coating and a projector, wherein the conductive coating comprises at least three conductive layers, wherein the total thickness of all conductive layers is at most 30 nm, and wherein the conductive layers have a thickness of 5 nm to 10 nm. Summary of the Invention

[0007] The purpose of this invention is to provide a further improved composite glass plate with sun protection function, wherein the electrical, energy and optical properties of the composite glass plate should be further improved.

[0008] According to the invention, this objective is achieved by a composite glass plate according to independent claim 1. Advantageous embodiments of the invention are derived from the dependent claims.

[0009] The composite glass pane according to the invention comprises an outer glass pane having an outer surface (side I) and a surface on the inner space side (side II), an inner glass pane having an outer surface (side III) and a surface on the inner space side (side IV), and a thermoplastic interlayer joining the surface on the inner space side of the outer glass pane to the outer surface of the inner glass pane, wherein the composite glass pane has at least one solar protection coating between the outer glass pane and the inner glass pane, which coating substantially reflects or absorbs rays outside the visible spectrum of solar radiation, in particular infrared rays, and wherein the solar protection coating comprises the following layer sequence when viewed in the direction from the inner glass pane towards the outer glass pane

[0010] - A first dielectric module (M1),

[0011] - A first silver layer (Ag1),

[0012] - A second dielectric module (M2),

[0013] - A second silver layer (Ag2),

[0014] - A third dielectric module (M3),

[0015] - A third silver layer (Ag3),

[0016] - A fourth dielectric module (M4).

[0017] The silver layers (Ag1, Ag2, Ag3) of the solar protection coating according to the invention have a relative layer thickness of Ag2 > Ag1 > Ag3 with respect to one another. Thus, the second silver layer Ag2 is the silver layer with the greatest thickness, followed by the first silver layer Ag1, whose thickness lies between the thickness of the second silver layer and the thickness of the third silver layer, and the third silver layer Ag3 is the silver layer with the smallest layer thickness. The first silver layer Ag1 and the third silver layer Ag3 have a relative layer thickness of 1.0 < Ag1 / Ag3 with respect to one another, while the second silver layer Ag2 and the third silver layer have a relative layer thickness of 1.2 < Ag2 / Ag3 < 2 with respect to one another. This has proven to be particularly advantageous for further improving the optical and electrical properties of the composite glass pane, especially with regard to the visually appealing blue reflection color of the coating at different reflection angles.

[0018] The structure of the sunscreen coating according to the invention, viewed from the direction starting from the inner glass plate, means that the fourth dielectric module is the layer of the sunscreen coating on the surface (side II) closest to the inner space side of the outer glass plate, and the first dielectric module is the layer of the sunscreen coating on the outer surface (side III) closest to the inner glass plate. On the first dielectric module (M1) closest to the outer surface (side III) of the inner glass plate, the layers following in sequence from the inner glass plate toward the outer glass plate are the first silver layer (Ag1), the second dielectric module (M2), the second silver layer (Ag2), the third dielectric module (M3), the third silver layer (Ag3), and the fourth dielectric module (M4). Therefore, the fourth dielectric module is the layer of the sunscreen coating on the surface (side II) furthest from the outer surface (side III) of the inner glass plate and closest to the inner space side of the outer glass plate. Silver layers are arranged here between the dielectric modules, i.e., the dielectric layers or the layer sequence. The sun-protective coating is disposed between the inner surface of the outer glass panel (side II) and the outer surface of the inner glass panel (side III), and may be applied, for example, to one of the glass panel surfaces or integrated into the thermoplastic interlayer.

[0019] In other words, according to the present invention, the thickness of the second silver layer (Ag2) of the sunscreen coating is greater than the respective thicknesses of the two other silver layers, Ag1 and Ag3, located above and below it. The first silver layer Ag1 is arranged below the second silver layer Ag2 in the layer sequence of the sunscreen coating and is therefore arranged further away from the outer glass plate, while the third silver layer Ag3 is arranged above the second silver layer Ag2 in the layer sequence and is therefore arranged closer to the outer glass plate. Furthermore, the thickness of the first silver layer Ag1 is greater than the thickness of the third silver layer Ag3.

[0020] Surprisingly, it has been shown that, compared to composite glass panels with sun-protective coatings known to date, the composite glass panel according to the present invention exhibits significantly improved electrical, optical, and aesthetic properties, while simultaneously possessing good energy performance. In particular, undesirable hues in the reflection of the composite glass panel can be minimized or even completely avoided. Furthermore, it achieves at most very low angle-dependent color variation in reflection. Moreover, the composite glass panel according to the present invention is compatible with a 14V / 42V DC voltage converter and can be heated using a 42V power supply when needed.

[0021] A composite glass panel comprises an outer glass panel and an inner glass panel bonded together by a thermoplastic interlayer. The composite glass panel is used to separate an interior space from the external environment in window openings, particularly in vehicle window openings. In the context of this invention, the inner glass panel refers to the glass panel of the composite glass panel facing the interior space (especially the interior space of a vehicle). The outer glass panel refers to the glass panel facing the external environment.

[0022] The composite glass panel has a top edge and a bottom edge, as well as two side edges extending therebetween. The top edge refers to the edge set to point upwards in the mounting position. The bottom edge refers to the edge set to point downwards in the mounting position. In the case of a windshield panel, the top edge is often also referred to as the top edge and the bottom edge as the engine edge.

[0023] The outer glass panel and the inner glass panel each have an outer surface and an inner space side surface, and a surrounding side edge extending therebetween. In the context of this invention, the outer surface refers to the main surface configured to face the external environment in the installation position. Similarly, the inner space side surface refers to the main surface configured to face the inner space in the installation position. The inner space side surface of the outer glass panel and the outer surface of the inner glass panel face each other and are bonded together by a thermoplastic interlayer.

[0024] The sun-protective coating of the composite glass panel according to the invention is preferably applied to one of the surfaces of the two glass panels facing the interlayer, i.e., the surface of the inner space side of the outer glass panel or the outer surface of the inner glass panel. Alternatively, the sun-protective coating may also be disposed within the thermoplastic interlayer, for example, applied to a carrier film disposed between the two thermoplastic bonding films. The sun-protective coating is also suitable as an infrared-reflective coating. In particular, the coating is applied to the entire surface of the glass panel, except for the perimeter area and optional local areas (which, as communication, sensor, or camera windows, should ensure the transmission of electromagnetic radiation through the composite glass panel and are therefore uncoated). For example, the uncoated perimeter area has a width of up to 20 cm. It prevents the coating from direct contact with the surrounding atmosphere, thereby protecting the coating inside the composite glass panel from corrosion and damage.

[0025] In a preferred embodiment, the composite glass panel is a windshield panel and the sun-protective coating is manufactured as a transparent coating. A transparent coating should be understood as a coating having an average transmittance of at least 70%, preferably at least 72.5%, in the visible spectrum, which does not significantly restrict visibility through the glass panel. A transmittance of at least 72.5% in the visible light range is particularly advantageous if additional components of the glass panel limit transmittance. The coating is suitable for heating via a power supply voltage preferably 42V, but can also be used as a pure sun-protective coating without the need for a corresponding electrical connector for heating. Depending on customer requirements, other heating devices, such as additional heating wires, can also be incorporated into such a composite glass panel (whose sun-protective coating does not have an electrical connector for contact with a voltage source). These further limit the transmittance through the glass panel, requiring the coating to have at least 72.5% transmittance. Surprisingly, the composite glass panel according to the invention meets this standard despite various limitations imposed by optical, energy, and electrical requirements.

[0026] Preferably, at least 80% of the glass plate surface is equipped with a coating according to the invention.

[0027] If the first layer is arranged above the second layer, this means, in the sense of the invention, that the first layer is arranged further toward the outer glass panel than the second layer. If the first layer is arranged below the second layer, this means, in the sense of the invention, that the second layer is arranged further toward the inner glass panel than the first layer.

[0028] If based on a material forming layer, then the layer is mainly composed of that material, in particular, it is essentially composed of that material except for possible impurities or dopants.

[0029] The sunscreen coating is a stack of layers or a sequence of layers, particularly formed from thin layers comprising multiple silver layers, each silver layer being disposed between two dielectric layers or sequences of layers. These dielectric layers or sequences of layers are called dielectric modules. A dielectric module is therefore understood to be a dielectric layer that can be formed from a single layer, i.e., a single dielectric layer, or from multiple dielectric layers. Thus, the coating is a stack of thin layers having n silver layers and (n+1) dielectric layers or sequences of layers, where n is a natural number, and wherein silver layers and dielectric layers or sequences of layers are alternately attached to the lower dielectric layers or sequences of layers, respectively.

[0030] The sunscreen coating is a thin-layer stack, i.e., a sequence of thin monolayers, and preferably includes at least four dielectric modules (M1, M2, M3, and M4), i.e., at least four dielectric layers. Each functional silver layer is disposed between two dielectric layers or layer sequences. The functional layers or layer sequences and dielectric layers are arranged such that at least one dielectric layer is disposed between each pair of adjacent functional silver layers (with no other functional silver layer disposed between them), and at least one other dielectric layer is disposed above the uppermost functional layer and below the lowermost functional layer.

[0031] The sunscreen coating according to the invention has at least three silver layers. Therefore, the natural number n is at least 3. The coating comprises at least the following layers or layer sequences, arranged in the order shown, starting from the inner glass plate and proceeding to the outer glass plate:

[0032] - As the first dielectric layer or layer sequence of module M1

[0033] -First silver layer Ag1,

[0034] - As the second dielectric layer or layer sequence of module M2

[0035] -Second silver layer Ag2,

[0036] - As the third dielectric layer or layer sequence of module M3,

[0037] -Third silver layer Ag3 and

[0038] - As the fourth dielectric layer or layer sequence of module M4.

[0039] The coating according to the invention may include additional silver layers and dielectric modules disposed above the fourth dielectric module M4 (n>3). However, in a particularly preferred embodiment, the natural number n is exactly 3. Therefore, the sunscreen coating preferably comprises exactly three silver layers, i.e., no less than three and no more than three silver layers. In principle, more complex layer structures are not required to achieve the desired coating specifications. Furthermore, the deposition of more complex layer structures is more expensive. In this respect, a major advantage of the invention is that the desired performance of the coating is achieved with only three silver layers. However, in addition to the silver layers, other metal-containing layers may be present, which do not significantly contribute to the sunscreen performance of the coating but serve other purposes. This is particularly suitable for metal barrier layers with a geometric thickness of less than 1 nm, which are preferably disposed between the silver layers and the dielectric modules.

[0040] The silver layer imparts the basic IR reflection effect to the sunscreen coating and the conductivity required for heating the glass plate. Here, the term "silver layer" is used to describe a layer based on a silver structure. The silver layer is based on a silver structure. Preferably, the silver layer contains at least 90% by weight of silver, particularly preferably at least 99% by weight of silver, and very particularly preferably at least 99.9% by weight of silver. The silver layer may have dopants, such as palladium, gold, copper, or aluminum.

[0041] The first dielectric module M1, the second dielectric module M2, the third dielectric module M3, and the fourth dielectric module M4 preferably have relative optical layer thicknesses of M2 / M1 ≥ 1.9, M2 / M3 > 0.8, and M2 / M4 ≥ 2. The composite glass plate with this sun-protective coating embodiment exhibits further improved optical and aesthetic properties, as well as higher transmittance T in the visible light range. L .

[0042] In one embodiment of the invention, all dielectric layers have a refractive index greater than 1.8, preferably greater than 1.9. In other words, all dielectric layers or layer sequences of the dielectric module are constructed solely of dielectric layers with a refractive index greater than 1.8. This achieves desirable results. The dielectric layers can be constructed, for example, based on silicon nitride (Si3N4), silicon-metal mixed nitrides (e.g., silicon zirconium nitride (SiZrN), silicon-aluminum mixed nitrides, silicon-hafnium mixed nitrides, or silicon-titanium mixed nitrides), aluminum nitride (AlN), tin oxide (SnO), manganese oxide (MnO), tungsten oxide (WO3), niobium oxide (Nb2O5), bismuth oxide (Bi2O5), titanium dioxide (TiO2), zinc oxide (ZnO), or tin-zinc mixed oxides (SnZnO).

[0043] In the context of this invention, the refractive index is typically given based on a wavelength of 550 nm. Optical thickness is the product of geometric thickness and refractive index (at 550 nm). The optical thickness of a layer sequence is calculated as the sum of the optical thicknesses of each individual layer. For example, the refractive index can be determined by ellipsometry. Ellipsometry meters are commercially available, for example from Sentech. The refractive index of the dielectric layer is preferably determined by first depositing it as a monolayer on a substrate and then measuring its refractive index by ellipsometry. To determine the refractive index of a dielectric layer sequence, each layer of the layer sequence is deposited individually as a monolayer on a substrate, and then its refractive index is determined by ellipsometry. In a preferred embodiment, a refractive index of at least 1.8 can be achieved for each of these monolayers. Dielectric layers having a refractive index of at least 1.8 and their deposition are known to those skilled in the art of thin layers. Physical vapor deposition methods, particularly magnetron sputtering, are preferred.

[0044] The materials mentioned in this specification can be deposited stoichiometrically, substoichiometrically, or superstoichiometrically. The materials may contain dopants, particularly aluminum, boron, zirconium, or titanium. Doping can impart a certain conductivity to the inherently dielectric material. However, those skilled in the art will functionally regard them as dielectric layers, as is common in the field of thin layers. The dielectric layer material preferably has a conductivity of less than 10. -4 The conductivity (reciprocal of specific resistance) is S / m. The material of the silver layer preferably has a conductivity greater than 10. 4 Conductivity in S / m.

[0045] The first, second, third, and / or fourth dielectric modules preferably include a dielectric layer serving as an anti-reflective layer. In an advantageous embodiment, each dielectric module includes a dielectric layer as an anti-reflective layer. This anti-reflective layer reduces the reflection of visible light, thus increasing the transparency of the coated glass plate. The anti-reflective layer is constructed, for example, based on silicon nitride (Si3N4), silicon-metal mixed nitrides such as zirconium silicon nitride (SiZrN), aluminum nitride (AlN), or tin oxide (SnO). The anti-reflective layer may also have dopants. The anti-reflective layer preferably has a geometric thickness of 5 nm to 100 nm, particularly preferably 6 nm to 60 nm. Silicon nitride is particularly preferred as an anti-reflective layer because it has a higher refractive index compared to oxides, thus requiring a relatively low silicon nitride layer thickness. Furthermore, good color performance of the coating is achieved.

[0046] In an advantageous embodiment, one or more dielectric modules, preferably at least each disposed beneath the silver layer, have a first adapter layer. The first adapter layer is preferably disposed above the anti-reflective layer. The first adapter layer is preferably disposed directly beneath the first silver layer such that it is in direct contact with its respective silver layer. This is particularly advantageous in terms of the crystallinity of the silver layer. In an advantageous embodiment, one or more dielectric modules, preferably each disposed above the silver layer, have a second adapter layer. The second adapter layer is preferably disposed beneath the anti-reflective layer.

[0047] The first and / or second adapter layer preferably comprises zinc oxide (ZnO). The first and / or second adapter layer also preferably comprises dopants. The first and / or second adapter layer may comprise, for example, aluminum-doped zinc oxide (ZnO:Al). The zinc oxide is preferably deposited in a substoichiometric manner with respect to oxygen to avoid excess oxygen reacting with the silver-containing layer. The geometric thickness of the first and second adapter layers is preferably 5 nm to 20 nm, particularly preferably 8 nm to 20 nm. Zinc oxide has proven to be a preferred material for adapter layers due to its excellent smoothing properties, in which advantageously high electrical conductivity can be achieved in adjacent silver layers.

[0048] In an advantageous embodiment, one or more dielectric modules, preferably each disposed between two silver layers, and particularly preferably the lowermost first dielectric module, have at least one dielectric layer as a smoothing layer. The at least one smoothing layer is disposed below the first adapter layer, preferably between the anti-reflective layer and the first adapter layer, if such a first adapter layer is present. The smoothing layer is particularly preferably in direct contact with the first adapter layer. The smoothing layer provides optimization, particularly for smoothing the surface of the silver layer subsequently applied above. The silver layer deposited on a smoother surface has higher transmittance while having lower sheet resistivity. The geometric thickness of the smoothing layer is preferably 5 nm to 20 nm, particularly preferably 7 nm to 12 nm. The smoothing layer preferably has a refractive index of less than 2.2.

[0049] The smoothing layer preferably comprises at least one amorphous oxide. This oxide can be amorphous or partially amorphous (and therefore partially crystalline), but not fully crystalline. The amorphous smoothing layer has low roughness and thus provides a favorable smooth surface for the layer applied over it. The amorphous smoothing layer also contributes to an improved surface structure for the layer deposited directly over it (preferably the first adapter layer). The smoothing layer may comprise 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 comprises an amorphous mixed oxide. The smoothing layer very particularly preferably comprises a tin-zinc mixed oxide (ZnSnO). The mixed oxide may have dopants. The smoothing layer may comprise, for example, an antimony-doped tin-zinc mixed oxide. The mixed oxide preferably has a substoichiometric oxygen content. The tin content is preferably 10 to 40% by weight, particularly preferably 12 to 35% by weight.

[0050] In an advantageous embodiment, the sunscreen coating includes one or more barrier layers. Preferably, at least one barrier layer is provided for each silver layer. The barrier layer is in direct contact with the silver layer and is disposed directly above or directly below the silver layer. Therefore, no other layer is disposed between the silver layer and the associated barrier layer. Alternatively, one barrier layer may be disposed directly above the silver layer and one directly below the silver layer. The barrier layer preferably comprises niobium, titanium, nickel, chromium, and / or alloys thereof, particularly nickel-chromium alloys. The geometric thickness of the barrier layer is preferably from 0.1 nm to 1.5 nm, particularly preferably from 0.1 nm to 1.0 nm. The barrier layer directly below the silver layer is particularly useful for stabilizing the silver layer during temperature processing and improving the optical quality of the sunscreen coating. The barrier layer directly above the silver layer prevents the sensitive silver layer from coming into contact with an oxidizing reactive atmosphere during the deposition of subsequent layers, such as a second adapter layer, by reactive cathode sputtering.

[0051] If based on a material forming layer, the layer is primarily composed of that material, except for possible impurities or dopants. If the first layer is disposed above the second layer, this in the sense of the invention means that the first layer is disposed further away from the substrate on which the coating is applied than the second layer. If the first layer is disposed below the second layer, this in the sense of the invention means that the second layer is disposed further away from the substrate than the first layer. If the first layer is disposed above or below the second layer, this does not necessarily mean that the first and second layers are in direct contact with each other in the sense of the invention. One or more other layers may be disposed between the first and second layers, unless this is explicitly excluded.

[0052] In an advantageous embodiment, dielectric modules are arranged between two adjacent silver layers, comprising the following dielectric layer sequence:

[0053] -Antireflective layers based on silicon nitride, silicon-metal-mixed nitrides such as silicon zirconium nitride, aluminum nitride, and / or tin oxide,

[0054] - A smoothing layer based on oxides of one or more of the elements tin, silicon, titanium, zirconium, hafnium, zinc, gallium, and indium.

[0055] - First and second adapter layers based on zinc oxide, and

[0056] - Optional barrier layers based on niobium, titanium, nickel, chromium, and / or their alloys. No particular layer order is required. An anti-reflective layer and an adapter layer based on the aforementioned preferred materials are preferably arranged below the bottom silver layer and above the top silver layer. In a preferred embodiment comprising three silver layers, the bottom silver layer corresponds to the first silver layer, and the top silver layer corresponds to the third silver layer.

[0057] The dielectric modules preferably have a geometric thickness of 10 nm to 100 nm, particularly preferably 20 nm to 90 nm, for example 70 nm to 85 nm. The optical thickness of the dielectric module is obtained by multiplying the geometric thickness of the dielectric module by the refractive index of each layer. The optical thickness of the dielectric module is 20 nm to 240 nm, preferably 40 nm to 200 nm.

[0058] The geometric thickness of each functional silver layer in the sunscreen coating is preferably between 5 nm and 25 nm. The total geometric thickness of all functional silver layers in the sunscreen coating is preferably between 20 nm and 75 nm, and particularly preferably between 25 nm and 60 nm. Within these ranges of functional layer thickness and total thickness of all functional silver layers, particularly good results are obtained in terms of sun protection function and transparency.

[0059] The first silver layer (Ag1) preferably has a geometric thickness of 7 nm to 14 nm, the second silver layer (Ag2) preferably has a geometric thickness of 7 nm to 16 nm, and the third silver layer (Ag3) has a geometric thickness of 6 nm to 13 nm. Layer thicknesses within these ranges have proven advantageous in achieving a film resistance of 1.0 Ω / square to 1.5 Ω / square for the sunscreen coating, which is particularly suitable for use with a power supply voltage of 42 V.

[0060] The sun-protective coating according to the invention has infrared reflective properties, and therefore, when used as a sun-protective coating, it reduces the temperature rise of the interior space of a vehicle by reflecting thermal radiation. The TTS value of the composite glass panel equipped with this coating is preferably less than 50%, particularly preferably less than 45%. The TTS value represents the total transmitted solar energy as measured according to ISO 13837—it is a measure of thermal comfort. The coating can also be used as a heating coating if it is electrically contacted, such that an electric current flows through it, heating the coating.

[0061] The outer and inner glass panes are preferably made of glass, particularly soda-lime glass, which is common for window panes. However, in principle, the glass 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 and inner glass panes can vary widely. Glass panes with a thickness of 0.8 mm to 5 mm are preferred, more preferably 1.4 mm to 2.9 mm, for example, glass panes with a standard thickness of 1.6 mm or 2.1 mm.

[0062] The outer glass pane, inner glass pane, and thermoplastic interlayer can be clear and colorless, but can also be colored or stained. The hue of the outer glass pane, inner glass pane, and thermoplastic interlayer is selected according to the desired application of the composite glass pane. If the composite glass pane is used as a windshield pane, high transmittance in the visible light range of the spectrum is desirable, and dark hues of the components are unnecessary. Based on light type A, in one embodiment as a windshield pane for a motor vehicle, the total transmittance through the composite glass pane is greater than 70%. The term total transmittance is based on the method for testing the light transmittance of motor vehicle glass panes specified in ECE-R 43, Annex 3, Section 9.1. The outer glass pane and inner glass pane can be unstressed, partially prestressed, or prestressed independently of each other. If at least one of the glass panes is prestressed, this can be thermal or chemical prestressing.

[0063] Suitable glass sheets include those known to Saint-Gobain under the trade names Planiclear and Planilux (each for clear glass), VG10, VG20, VG40, or TSANx, TSA3+, TSA4+, where the VG series glass is gray-stained and the TSA series glass is green-stained.

[0064] In a preferred embodiment, the composite glass panel is configured as the windshield of a motor vehicle, wherein at least the thermoplastic interlayer, the inner glass panel, and the outer glass panel are clear.

[0065] The composite glass panel is preferably curved in one or more directions in space, as is common for automotive glass panels, where the typical radius of curvature is from about 10 cm to about 40 m. The composite glass panel can also be flat, for example, if it is used as a glass panel for buses, trains, or tractors.

[0066] The inner surface of the outer glass panel and the outer surface of the inner glass panel face each other and are bonded together by a thermoplastic interlayer. The thermoplastic interlayer is constructed of one or more thermoplastic films, wherein in the resulting composite glass panel, the individual films in the resulting interlayer are optionally indistinguishable from each other. The thermoplastic films preferably contain polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), polyurethane (PU), and / or mixtures and / or copolymers thereof, with polyvinyl butyral being particularly preferred. The films are preferably constructed based on the aforementioned materials, but may contain other components, such as plasticizers, colorants, IR or UV absorbers.

[0067] The thermoplastic interlayer comprises at least one thermoplastic polymer, preferably ethylene vinyl acetate (EVA), polyvinyl butyral (PVB), or polyurethane (PU), or mixtures, copolymers, or derivatives thereof, with PVB being particularly preferred. The thickness of the interlayer is preferably from 0.2 mm to 2 mm, particularly preferably from 0.3 mm to 1 mm. The individual polymer films of the interlayer, especially the PVB films, preferably have a thickness of about 0.2 mm to 1 mm, for example, 0.38 mm, 0.76 mm, or 0.81 mm. Other properties of the composite glass can be influenced by the thickness of the films. For example, slightly thicker PVB films can achieve improved sound insulation (especially when they contain an acoustically active core), increased burglarproof properties of the composite glass, and increased protection against ultraviolet radiation (UV protection).

[0068] According to the invention, a sun-protective coating is disposed between the outer glass panel and the inner glass panel. In a preferred embodiment, the sun-protective coating is applied to the surface (side II) of the inner space side of the outer glass panel. The sun-protective coating is thus protected from weather conditions within the laminate of the composite glass panels. Positioning the sun-protective coating as far to the outside as possible, i.e., as close as possible to the outer edge of the outer glass panel, is advantageous for particularly good sun protection. This is further optimized by using a clear, uncoated outer glass panel.

[0069] In another possible embodiment, the sun-protective coating is embedded in the thermoplastic interlayer. The sun-protective coating can be applied to the thermoplastic film. In a preferred embodiment, the sun-protective coating is applied to a carrier film, which is arranged, for example, between two thermoplastic films used to construct the interlayer during the manufacture of the composite glass panel. Integrating the sun-protective coating onto the carrier film is advantageous for simple prefabrication and for providing the sun-protective coating to the carrier film. The film of the thermoplastic interlayer located between the sun-protective coating and the outer glass panel is preferably clear and uncolored. The thermoplastic interlayer of the composite glass panel comprises a carrier film on top, i.e., on the surface facing the outer glass panel, having the sun-protective coating. The carrier film preferably comprises or is composed of polyethylene terephthalate (PET) and has a thickness of 20 μm to 100 μm, for example, about 50 μm. However, the carrier film can also be made of other suitable plastics.

[0070] In another preferred embodiment, a sun-protective coating is applied to the outer surface III of the inner glass plate. In this case, the outer glass plate and the thermoplastic interlayer are preferably clear and uncolored. This embodiment is advantageous depending on the location of the opaque overprint in the edge area, and here greater flexibility is achieved in terms of the printing inks that can be used to cover the overprint.

[0071] If the sunscreen coating is configured as a heated coating, it is electrically connected to an external voltage source in a manner known per se, wherein the coating is heated by applying voltage. Electrical contact is achieved via a suitable connecting cable, such as a membrane conductor, which is preferably connected to the sunscreen coating via a so-called busbar, such as a strip of conductive material or conductive printing.

[0072] At least two buses are preferably disposed on and electrically connected to the sun-protective coating. The at least two buses are preferably disposed along opposite edges of the composite glass plate and can be electrically connected to the opposite pole of a voltage source to heat the glass plate. The coated area between the buses is electrically heated. In one possible embodiment of the invention, three buses are applied, with each bus extending parallel to a horizontal edge, and a third bus projecting from the top edge toward the center of the glass plate. The first bus is located near the top edge, while the second bus is adjacent to the engine edge, and two buses extend parallel to these horizontal side edges. In a particularly preferred embodiment, one or more buses are shaped to fit a possible uncoated area of ​​the sensor window for housing the sensor. The buses have a thickness of 5 μm to 20 μm, preferably 8 μm to 15 μm. The buses have a width of 0.5 mm to 30 mm, preferably 1 mm to 20 mm.

[0073] In another preferred embodiment, the sun-protective coating is not provided for connection to a voltage source. Optionally, other means for heating the glass plates, such as heating wires, are provided, positioned between the outer surface (side III) of the inner glass plate and the surface (side II) of the inner space side of the outer glass plate. The heating wire is preferably embedded in a thermoplastic interlayer. The heating wire may optionally be electrically insulated. This achieves contact between the wire and the coating while preventing short circuits. The composite film equipped with the thermoplastic interlayer containing the heating wire can therefore be positioned with the wire pointing towards the coating. If the wire is not insulated, the heating wire should be located on the side of the composite film facing away from the coating. Insulation of the wire is achieved, for example, by a polymer-containing coating, which particularly preferably comprises polyethylene, polyvinyl chloride, polytetrafluoroethylene, polyester, polycarbonate, rubber, silicone rubber, polyamide, polyurethane, and / or mixtures and / or copolymers thereof.

[0074] The minimum distance between adjacent heating wires is 2mm, while the maximum distance between adjacent heating wires is 35mm.

[0075] The heating wire contains tungsten, copper, nickel, manganese, aluminum, silver, chromium and / or iron and / or mixtures and / or alloys thereof, preferably tungsten or copper, with tungsten being particularly preferred.

[0076] The heating wire has a thickness of 5 μm to 160 μm, where the thickness depends particularly on the material used in the wire. Tungsten wire is preferably used with a thickness of 10 μm to 80 μm, while copper wire is preferably used with a thickness of 60 μm to 150 μm.

[0077] The heating wires have multiple electrical conductors at their ends, preferably two conductors in contact. Other contact methods may be chosen depending on the orientation of the heating wires, such as a meandering or zigzag shape. In the case of continuous meandering wires, for example, only point-like voltage needs to be applied to both ends of the wire.

[0078] The composite glass panel preferably has an external energy reflectivity (RE) greater than 30%. The energy value (RE) is calculated according to ISO 9050 standard.

[0079] In the edge regions of the glass plate, an opaque overlay, such as a screen print, is preferably applied to define the field of view of the glass plate or to form its outer edge. Buses and conductors that may be arranged in the edge regions of the glass plate, as well as optional uncoated edge regions, are preferably covered by the overlay and thus visually obscured. The opaque screen print can be applied to any plane of the composite glass plate.

[0080] The present invention also includes a method for manufacturing a composite glass plate with a sun-protective coating according to the present invention, comprising the following method steps.

[0081] a) Apply the sun-protective coating to the inner surface II of the outer glass panel or the outer surface III of the inner glass panel, or introduce the sun-protective coating into the thermoplastic interlayer.

[0082] b) A laminate manufactured in a sequence comprising at least an outer glass sheet, a thermoplastic intermediate layer, and an inner glass sheet, and

[0083] c) Joining at least an outer glass plate, a thermoplastic intermediate layer and an inner glass plate into a composite glass plate.

[0084] The bonding of the outer and inner glass panels into composite glass is preferably carried out after a sun-protective coating has been applied.

[0085] The sun-protective coating can withstand high heat loads, so it can also withstand temperature treatment or bending of the glass plate at temperatures typically exceeding 600°C without damage.

[0086] The individual layers of the sunscreen coating can be deposited by methods known per se, preferably by magnetic field-assisted cathodic sputtering, and constructed with suitable layer thicknesses and layer sequences. Cathodic sputtering can be performed, for example, in a protective gas atmosphere made of argon, or in a reactive gas atmosphere, for example, by adding oxygen or nitrogen. However, the individual layers can also be applied by other suitable methods known to those skilled in the art, such as vapor deposition or chemical vapor deposition.

[0087] The thermoplastic interlayer can be provided in the form of a thermoplastic film. However, the thermoplastic interlayer can also be in the form of multiple films, such as two or more thermoplastic films, optionally with an additional carrier film. Applying a sun-protective coating to the thermoplastic interlayer here only includes applying the sun-protective coating to one of the films, such as the carrier film. The carrier film having the sun-protective coating disposed thereon is preferably disposed between the two thermoplastic films when joining the glass plates into composite glass, wherein the side with the sun-protective coating faces outward toward the glass plate.

[0088] The conductive layer is applied before lamination of the composite glass plate via electrical contacts through a busbar or other suitable electrical conductor.

[0089] Any existing prints, such as opaque overlay prints or printed busbars for electrical contacts of the sunscreen coating, are preferably applied in a screen printing process.

[0090] The outer and inner glass panels are joined together to form a composite glass panel via a thermoplastic interlayer, preferably by lamination under heat, vacuum, and / or pressure. Methods known per se for manufacturing composite glass panels can be used. During lamination, a heated, flowable thermoplastic material flows around the sun-protective coating, thereby forming a stable composite that encapsulates the sun-protective coating within the interlayer and protects it from damage and environmental impacts.

[0091] For example, the so-called autoclave method can be carried out for about 2 hours at a high pressure of about 10 to 15 bar and a temperature of 130°C to 145°C. Vacuum bag or vacuum ring methods, known per se, operate, for example, at about 200 mbar and 80°C to 110°C. The outer glass sheet, thermoplastic intermediate layer, and inner glass sheet can also be pressed into glass sheets in a calender between at least one pair of rollers. This type of equipment is known for manufacturing glass sheets and typically has at least one heating passage before the press. The temperature during the pressing process is, for example, 40°C to 150°C. The combination of calendering and autoclave methods has proven particularly useful. Alternatively, vacuum laminators can be used. These consist of one or more heated and vacuum-ejectable chambers in which the glass sheets are laminated for, for example, about 60 minutes at a reduced pressure of 0.01 mbar to 800 mbar and a temperature of 80°C to 170°C.

[0092] The present invention further includes the use of composite glass panels with sun-protective coatings according to the invention in land, sea and air transportation vehicles, particularly in motor vehicles, for example as windshield panels, rear glass panels, side glass panels and / or roof glass panels, as functional components, and in buildings.

[0093] All standards mentioned are based on the version valid as of the application date.

[0094] Various embodiments of the present invention can be implemented individually or in any combination. In particular, without departing from the scope of the invention, the features mentioned above and explained below can be used not only in the combinations shown, but also in other combinations or individually. Unless the embodiments and / or their features are explicitly mentioned, they are only alternatives or mutually exclusive.

[0095] The invention will now be described in more detail with reference to the accompanying drawings. It should be noted that different aspects are described, each of which can be used individually or in combination. That is, each aspect can be used with different embodiments of the invention unless explicitly stated as a purely alternative. Attached Figure Description

[0096] The accompanying drawings are simplified schematic diagrams and are not drawn to scale. The drawings do not limit the invention in any way.

[0097] in:

[0098] Figure 1 A cross-section of a first embodiment of a composite glass plate with a sun-protective coating according to the present invention is shown.

[0099] Figure 2 A cross-section of another embodiment of the composite glass plate with a sun-protective coating according to the present invention is shown.

[0100] Figure 3 A cross-section of another embodiment of the composite glass plate with a sun-protective coating according to the present invention is shown.

[0101] Figure 4 A schematic diagram of the structure of the sun-protective coating according to the invention applied to the inner glass plate of a composite glass plate is shown, and Figure 5 A flowchart illustrating an embodiment of the method according to the present invention is shown. Detailed Implementation

[0102] Figure 1Shows a cross-section of an embodiment of a composite glass pane 100 with a sun protection coating 4 according to the invention. The composite glass pane 100 comprises an outer glass pane 1 and an inner glass pane 2, which are joined to one another by a thermoplastic interlayer 3. The composite glass pane 100 can for example be provided as a windshield glass pane of a motor vehicle carrying people, wherein the outer glass pane 1 faces the external environment and the inner glass pane 2 faces the interior space of the vehicle. The outer glass pane 1 has an outer surface (I) and an inner surface (II). The inner glass pane 2 has an outer surface (III) and an inner surface (IV). The outer surfaces (I) and (III) face the external environment, and the inner surfaces (II) and (IV) face the interior space of the vehicle. The inner surface (II) of the outer glass pane 1 and the outer surface (III) of the inner glass pane 2 face one another. In this embodiment, the sun protection coating 4 according to the invention is arranged on the inner surface (II) of the outer glass pane 1. The sun protection coating 4 extends over the entire inner surface (II), preferably minus a circumferential frame-shaped uncoated area, for example with a width of 8 mm. This uncoated area can then be hermetically sealed by gluing with the thermoplastic interlayer 3. Thereby, the sun protection coating 4 is advantageously protected from damage and corrosion. According to the invention, the sun protection coating 4 comprises at least three functional silver layers, each having a geometric layer thickness of 5 nm to 20 nm, wherein each functional silver layer is arranged between dielectric modules, for example layers made of silicon nitride. The silver layers (Ag1, Ag2, Ag3) of the sun protection coating according to the invention have relative layer thicknesses of 1.0 < Ag1 / Ag3 and 1.2 < Ag2 / Ag3 < 2 with respect to one another, where Ag2 > Ag1 > Ag3 applies. The dielectric modules (M1, M2, M3, M4) have relative optical layer thicknesses of M2 / M1 ≥ 1.9, M2 / M3 ≥ 0.8 and M2 / M4 ≥ 2 with respect to one another. The following describes the structure of the sun protection coating 4 according to the invention in more detail with reference to Figure 4 and the examples and comparative examples explained there. Due to the reflection of infrared radiation, the sun protection coating 4 causes a reduction in the heating of the interior space of the vehicle and the inner glass pane 2. An energy reflectance of RE > 30%, a total solar transmittance of TTS < 45% and a light transmittance of TL > 72.5% can be achieved. In addition, with the sun protection coating 4 according to the invention, in addition to improved good thermal comfort, good optical and aesthetic properties of the composite glass pane 100 are also achieved simultaneously. The film resistance of the sun protection coating 4 is 1.0 Ω / square to 1.5 Ω / square, thereby enabling good compatibility of the coating with 14V / 42V DC voltage converters.

[0103] Figure 2 Shows a cross-section of another embodiment of a composite glass pane 100 with a sun protection coating 4 according to the invention. Compared with Figure 1Differently, the sun protection coating 4 is not arranged on the inner surface (II) of the outer glass plate 1, but on the carrier film 5 in the interlayer 3. The carrier film 5 comprises or preferably consists of polyethylene terephthalate (PET) and has a thickness of, for example, 50 μm. The sun protection layer 4 according to the invention comprises a layer structure which is explained in more detail with respect to Figure 4 The carrier film 5 with the sun protection coating 4 is arranged between the first thermoplastic film 3a and the second thermoplastic film 3b. The thermoplastic films 3a and 3b and the carrier layer 5 form a thermoplastic interlayer 3 in the resulting composite glass plate. The thermoplastic films 3a and 3b comprise PVB or preferably consist of PVB and have a layer thickness of, for example, 0.38 mm. The carrier film 5 has dimensions which are slightly smaller than those of the outer glass plate 1, the inner glass plate 2 and the thermoplastic films 3a and 3b. The carrier film 5 is arranged in the composite in such a way that the carrier film 5 does not extend to the side edges of the composite glass. The carrier film 5 is thus surrounded by the thermoplastic films 3a and 3b in the edge region of the composite glass plate, for example having a width of about 8 mm. The sun protection coating 4 on the carrier film 5 is thus advantageously protected against damage, in particular against corrosion.

[0104] Figure 3 Fig. shows a cross section of another embodiment of a composite glass plate 100 according to the invention with a sun protection coating 4. Different from Figure 1 The sun protection coating 4 is not arranged on the inner surface (II) of the outer glass plate 1, but on the outer surface (III) of the inner glass plate 2, wherein the circumferential edge region of the outer surface (III) is not provided with the sun protection coating 4. In this embodiment, the sun protection coating 4 is also advantageously protected against damage and corrosion. In addition, this embodiment corresponds to Figure 1 The embodiment shown.

[0105] Figure 4 Fig. shows a schematic structure of the sun protection layer 4 according to the invention. In the embodiment shown, the sun protection coating 4 is applied to the inner side III of the inner glass plate 2 serving as a substrate. The sun protection coating 4 shown comprises three transparent functional silver layers Ag1, Ag2 and Ag3, which are in particular infrared radiation reflecting layers. These functional silver layers have specific relative thicknesses with respect to one another; in particular, it is set that Ag2 > Ag1 > Ag3, 1.0 < Ag1 / Ag3 and 1.2 < Ag2 / Ag3 < 2 apply to the relative geometric layer thicknesses. In other words, the layer thickness of the third silver layer Ag3 arranged closest to the outer glass plate 1 is thinner than the layer thickness of the first silver layer Ag1 arranged closest to the inner glass plate 2, while the second silver layer Ag2 located between the first silver layer Ag1 and the third silver layer Ag3 in the layer sequence is the silver layer with the largest layer thickness. For example, the silver layers can be deposited by cathodic sputtering in an argon atmosphere.

[0106] Dielectric modules M1, M2, M3, and M4, including dielectric layers, are arranged above, below, and between silver layers Ag1, Ag2, and Ag3, respectively. These dielectric modules (M1, M2, M3, M4) preferably have relative optical layer thicknesses of M2 / M1 ≥ 1.9, M2 / M3 ≥ 0.8, and M2 / M4 ≥ 2. Dielectric module M1 is therefore directly arranged on the inner side III of the inner glass plate 2 and below the first silver layer Ag1, while the second dielectric module M2 is arranged above the first silver layer Ag1. The first dielectric module M1 can, for example, be constructed from the inner glass plate 2 as a layer sequence of silicon nitride, ZnSnOx, and ZnO layers. The silicon nitride layer can be deposited in a nitrogen-containing atmosphere, and the zinc oxide layer can be deposited in an oxygen-containing atmosphere.

[0107] The sun-protective coating 4 comprises at least one barrier layer, and particularly preferably, each functional silver layer Ag1, Ag2, Ag3 is in direct contact with at least one barrier layer B1, B2, and B3 as shown. According to the invention, the barrier layer preferably comprises at least nickel, chromium, or alloys thereof, and / or titanium-chromium, or is composed of these. The barrier layers B (B1, B2, B3) are preferably disposed between at least one functional silver layer and at least one dielectric layer. Through the barrier layers B, protection of the functional layers is achieved during heating, particularly during the manufacture of the composite glass plate according to the invention.

[0108] The present invention is illustrated by the following embodiments according to the invention and comparative examples not according to the invention.

[0109] Example

[0110] All optical, aesthetic, and energy properties of the composite glass plates according to the embodiments and comparative examples were measured in a laminated state. In the embodiments and comparative examples, sunscreen coating 4 was applied to the composite glass plates according to the embodiments and comparative examples. Figure 4 On the outer III of the clear inner glass plate 2 (e.g., Planiclear) and according to Figure 3 The structure is laminated with a thermoplastic interlayer 3 and an outer glass plate 1. An uncolored PVB film is used in the interlayer. The embodiments and comparative examples have the same basic structure, but use different sun-protective coatings.

[0111] According to Embodiments 1 to 5 of the present invention and Comparative Examples 1 to 3 of the non-present invention, composite glass panels (vehicle windshields) having the shown sun-protective coating are manufactured.

[0112] For each embodiment and comparative example, the stacked structure (layers and layer thicknesses) of the sun-protective coating and the optical properties of the coating in the finished composite glass plate are shown.

[0113] The layer sequence and layer thickness of the sunscreen coatings according to Embodiments 1 to 5 of the present invention, and comparative Examples 1 to 3 shown therein, are presented in Table 1. The relative layer thicknesses of the silver layer and the dielectric module, as well as the values ​​of optical, electrical, and energy properties, are shown in Table 2 for Embodiments 1 to 5 of the present invention and for comparative Examples 1 to 3 not according to the present invention. All layer thicknesses of the silver layer and the module are given as geometric layer thicknesses. The relative layer thicknesses of the silver layer shown as thickness ratios Ag2 / Ag1, Ag2 / Ag3, and Ag1 / Ag3 refer to geometric layer thicknesses. For the relative layer thicknesses of the dielectric module shown as thickness ratios M2 / M1, M2 / M3, and M2 / M4, optical thicknesses are used.

[0114] meaning:

[0115] RE Energy Reflectivity [%)

[0116] TL Visible light transmittance [%)

[0117] Total transmitted thermal radiation (TTS) [%)

[0118] Total Transmitted Energy (TE) [%)

[0119] Visible reflectance at an 8° viewing angle (RL) [%)

[0120] RL 60° Visible reflectance at a 60° viewing angle [%)

[0121] The color coordinates in the a* and b* CIE (International Commission on Illumination) color spaces, measured at reflections at 60° and 8° respectively.

[0122] The difference between the color coordinates of Δa* and Δb* measured at 60° and 8° reflection.

[0123] Color R* refers to the color impression perceived by an observer of the composite glass panel when reflected at 60° and 8°, respectively, by the externally reflected color.

[0124] Rsq is the film resistor with a sun-protective coating [Ω / square].

[0125] The values ​​of transmittance (TL) and reflectance (RL) are based on light type A, which is defined according to the relative radiation distribution of a Planck radiator with 2856 Kelvin.

[0126] Table 1: Layer structure of sunscreen coatings according to Examples 1 to 5 and Comparative Examples 1 to 3

[0127]

[0128] Table 2: Thickness ratios and optical properties of laminates according to Examples 1 to 5 and Comparative Examples 1 to 3

[0129] According to the present invention, there is provided a composite glass pane having a sunscreen coating constructed according to the present invention, which can be improved in terms of energy and electrical properties, thermal and visual comfort, and at the same time in terms of aesthetic appearance and further optimized compared to known composite glass panes having a sunscreen coating. A total transmitted thermal radiation (TTS) below 45% can be achieved, so that the corresponding customer requirements often put forward can be followed. In addition, a light transmittance of TL≥72.5% can be achieved, so that the composite glass pane can be used as a windshield glass pane and even meets the legal requirement of TL≥70% when combined with a conventional wire heating device. In addition, an optimal aesthetic appearance is achieved without unwanted hues in the reflection of the composite glass pane. In particular, unwanted red, yellow, purple, and green reflections or turbidity of the composite glass pane can be avoided. A substantially constant and desired color reflection of the composite glass pane can be achieved, independent of the viewing angle. In addition, the sunscreen coating according to the present invention has a film resistance of 1.0 Ω / square to 1.5 Ω / square and is therefore very suitable for heating with a power supply voltage of 42V.

[0130] To further clarify the advantages of the silver layer thickness combinations according to the present invention, the optical and energy properties of silver coatings with the respectively given silver layer thickness ratios are exemplarily given in Table 3. The thickness of the dielectric module and the layer sequence in the layer stack are the same in each case here.

[0131] Table 3: Overview of the optical properties TL, TTS, RL 60°, and external reflection color at 60° for various possible thickness ratios of the silver layers Ag1, Ag2, and Ag3

[0132] Arrangement Ag TL TTS RL 60° a*R 60° b*R 60° Ag1>Ag2>Ag3 73.1 43.4 17.9 -8.0 -1.5 Ag1>Ag3>Ag2 69.3 43.3 21.3 -13.6 5.7 Ag2>Ag1>Ag3 74.6 42.9 17.1 -1.0 -3.5 Ag2>Ag3>Ag1 72.7 42.4 19.6 -0.2 3.6 Ag3>Ag1>Ag2 67.6 42.7 23.9 -11.8 11.8 Ag3>Ag2>Ag1 69.5 42.3 23.0 -5.5 11.8 Ag1=Ag2=Ag3 (10.7 nm) 72.0 43.2 19.6 -7.7 4.4 。

[0133] As can be seen in Table 3, good optical and energy properties and an attractive coloring can only be achieved with the silver layer thickness ratios according to the present invention, where for the silver layer thicknesses Ag2>Ag1>Ag3 applies. Layers with the following properties are classified as acceptable: TL≥72.5%, TTS≤45%, RL 60°≤17.5%. In addition, the color coordinates should have the smallest possible absolute values and particularly preferably have a negative sign. As can be seen from Table 2, only for the thickness combination according to the present invention of Ag2>Ag1>Ag3, 1.0>Ag1 / Ag3 and 1.2<Ag2 / Ag3<2, the desired blue reflection color is achieved both at an 8° viewing angle and at a 60° viewing angle. A blue hue is obtained within this color range, which has a particularly high acceptance on the customer side. Here, it is particularly advantageous that the value of a*R 60° is from -5.0 to 0, and the value of b*R60° is likewise from -8.0 to 0.

[0134] Figure 5 An embodiment of the method according to the present invention is illustrated with the aid of a flowchart including the following steps.

[0135] I. Provide an outer glass plate 1, an inner glass plate 2, and at least one thermoplastic film for forming a thermoplastic interlayer 3; II. Apply a sun-protective coating 4 according to the invention to the inner surface II of the outer glass plate 1 or the outer surface III of the inner glass plate 2, for example by cathode sputtering;

[0136] III Optional: Apply the busbar to the sun protection coating 4;

[0137] IV. The inner surface II of the outer glass plate 1 and the outer surface III of the inner glass plate 2 are joined together by a thermoplastic interlayer 3 to form a composite glass plate 100.

[0138] In one embodiment, glass plates are used as an outer glass plate 1 and an inner glass plate 2. In a preferred embodiment of the method, a sun-protective coating 4 having at least three functional silver layers Ag1, Ag2, and Ag3 and at least four dielectric modules M1, M2, M3, and M4 is applied to the outer surface III of the inner glass plate 2, preferably by magnetic field-assisted cathode sputtering. If the glass plate is to be heated through the sun-protective coating 4, a busbar is placed on the sun-protective coating 4 and an electrical connection cable is installed to achieve electrical contact of the coating before laminating the glass. The outer glass plate 1 and the inner glass plate 2 are joined together to form a composite glass via an intermediate layer 3, preferably after the application of the sun-protective coating 4.

[0139] List of reference numerals

[0140] 1. Outer glass panel

[0141] 2. Inner glass plate

[0142] 3. Thermoplastic interlayer

[0143] 3a First thermoplastic film

[0144] 3b Second thermoplastic film

[0145] 4. Sunscreen coating

[0146] 5. Carrier membrane

[0147] I 1 outer surface

[0148] Inner surface of II 1

[0149] III 2 outer surface

[0150] Inner surface of IV 2

[0151] Ag1 First Silver Layer

[0152] Ag2 Second Silver Layer

[0153] Ag3 Third Silver Layer

[0154] M1 First Dielectric Module

[0155] M2 Second Dielectric Module

[0156] M3 Third Dielectric Module

[0157] M4 Fourth Dielectric Module

[0158] B Barrier Layer

[0159] B1 First Barrier Layer

[0160] B2 Second Barrier Layer

[0161] B3 Third barrier layer.

Claims

1. Laminated glass pane (100), comprising an outer glass pane (1) having an outer surface and an inner surface, an inner glass pane (2) having an outer surface and an inner surface, and a thermoplastic interlayer (3) that joins the inner surface of the outer glass pane (1) to the outer surface of the inner glass pane (2), wherein the laminated glass pane (100) has at least one solar protection coating (4) between the outer glass pane (1) and the inner glass pane (2), and wherein the solar protection coating (4) comprises the following layer sequence in the direction from the inner glass pane (2) towards the outer glass pane (1). - A first dielectric module M1, - A first silver layer Ag1, - A second dielectric module M2, - A second silver layer Ag2, - A third dielectric module M3, - A third silver layer Ag3, - A fourth dielectric module M4, wherein the silver layers comprised in the solar protection coating (4) are exactly three, Ag1, Ag2, Ag3, and wherein the silver layers Ag1, Ag2, Ag3 have a relative geometric layer thickness of Ag2 > Ag1 > Ag3 with respect to each other, and the silver layers Ag1, Ag2, Ag3 of the solar protection coating have a relative geometric layer thickness of 1.0 < Ag1 / Ag3 and 1.2 < Ag2 / Ag3 < 2.

2. Laminated glass pane (100) according to claim 1, wherein the dielectric modules M1, M2, M3, M4 have a relative optical layer thickness of M2 / M1 ≥ 1.9, M2 / M3 ≥ 0.8 and M2 / M4 ≥ 2.

3. Laminated glass pane (100) according to claim 1 or 2, wherein the first dielectric module M1, the second dielectric module M2, the third dielectric module M3 or the fourth dielectric module M4 has at least one dielectric layer based on silicon nitride.

4. Laminated glass pane (100) according to any one of claims 1 to 2, wherein the first dielectric module M1, the second dielectric module M2, the third dielectric module M3 or the fourth dielectric module M4 comprises at least one first dielectric layer based on silicon nitride and at least one second dielectric layer based on zinc oxide.

5. Laminated glass pane according to any one of claims 1 to 2, wherein the first dielectric module M1, the second dielectric module M2, the third dielectric module M3 or the fourth dielectric module M4 comprises at least one first dielectric layer based on silicon nitride, at least one second dielectric layer based on zinc oxide and at least one third dielectric layer based on a tin-zinc mixed oxide.

6. Laminated glass pane according to any one of claims 1 to 2, wherein the solar protection coating (4) comprises at least one metal barrier layer B1, B2, B3 above and / or below the silver layers Ag1, Ag2, Ag3, and the metal barrier layer has a geometric thickness of less than 1 nm. ​ 8. The composite glass plate according to claim 7, wherein the first silver layer Ag1 has a geometric thickness of 7 nm to 14 nm, the second silver layer Ag2 has a geometric thickness of 7 nm to 16 nm, and the third silver layer Ag3 has a geometric thickness of 6 nm to 13 nm.

9. The composite glass plate according to any one of claims 1 to 2, wherein the first dielectric module M1, the second dielectric module M2, the third dielectric module M3 and the fourth dielectric module M4 each have a geometric thickness of 10 nm to 100 nm.

10. The composite glass plate according to claim 9, wherein the first dielectric module M1, the second dielectric module M2, the third dielectric module M3 and the fourth dielectric module M4 each have a geometric thickness of 70 nm to 85 nm.

11. The composite glass panel according to any one of claims 1 to 2, wherein the sun-protective coating (4) is applied to the outer surface of the inner glass panel (2).

12. The composite glass plate according to any one of claims 1 to 2, wherein the sun protection coating (4) has at least two busbars, and the sun protection coating (4) can be connected to a voltage source through the busbars.

13. The composite glass plate according to any one of claims 1 to 2, wherein the heating wire is present between the outer surface of the inner glass plate (2) and the inner surface of the outer glass plate (1).

14. A method for manufacturing a composite glass plate (100) according to any one of claims 1 to 13, comprising at least the following method steps: a) Apply the sun-protective coating (4) to the inner surface of the outer glass plate (1) or the outer surface of the inner glass plate (2), or introduce the sun-protective coating (4) into the thermoplastic interlayer (3). b) A laminated body comprising, in the order of manufacture, at least an outer glass plate (1), a thermoplastic intermediate layer (3), and an inner glass plate (2), and c) Joining at least the outer glass plate (1), the thermoplastic intermediate layer (3) and the inner glass plate (2) into a composite glass plate (100).

15. Use of the composite glass panel (100) according to any one of claims 1 to 13 in a motor vehicle as a windshield panel, rear window panel, side window panel and / or roof window panel.

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