Composite glass pane

Abstract

The present invention relates to a composite glass plate (1) and a method for manufacturing the same. The composite glass plate (1) comprises a laminated stacked sequence consisting of an outer glass plate (2) having an outer surface (I) and an inner space side surface (II), an inner glass plate (3) having an outer surface (III) and an inner space side surface (IV), and at least one thermoplastic interlayer (4) connecting the inner space side surface (II) of the outer glass plate (2) and the outer surface (III) of the inner glass plate (3), wherein a heatable element (5) is applied directly to the inner space side surface (II) of the outer glass plate (2) or to the outer surface (III) of the inner glass plate (3), and a heat-reflecting coating (6) is applied directly to the inner space side surface (IV) of the inner glass plate (3) and / or the heat-reflecting coating (6) is applied directly to the outer surface (I) of the outer glass plate (2).

Description

[0001] This invention relates to an electrically heatable composite glass plate and its manufacturing method.

[0002] Glass panels with electrically heated layers are known and have been described multiple times in patent literature. Reference, by way of example only, is made to DE 102008018147 A1, DE 102008029986 A1, and WO 00 / 7263 A1. In motor vehicles, they are frequently used as windshields because, by law, no visual restriction is permitted in the central field of vision other than a heating wire. The heat generated by the heated layer can remove condensed moisture, ice, and snow in a short time. Such glass panels are mostly manufactured as composite glass panels, in which two monolithic glass panels are joined together by a thermoplastic adhesive layer. The heating layer can be applied to one of the inner surfaces of the monolithic glass panels, but structures located on a carrier arranged between the two monolithic glass panels are also known. Alternatively, the composite glass panel can also be heated by means of a heating wire. A composite glass panel with a heatable wire is disclosed in DE 103 52 464 A1.

[0003] In transportation vehicles, the existing heatable composite glass panel is a major energy consumer. In this type of panel, the heating element, i.e., the heating wire or heatable layer, is typically located on the outer side of the inner glass panel. When voltage is applied, the heating element heats up, and the heat is transferred through thermal conduction to the thermoplastic interlayer, outer glass panel, and inner glass panel of the composite glass panel. Since glass is generally a better conductor of heat than the thermoplastic interlayer, the heat from the heating element located on the outer side of the inner glass panel is primarily conducted to the inner glass panel and almost entirely bypassed to the outer glass panel. The emissivity of standard glass is approximately 80% to 90%. Therefore, for the existing heatable composite glass panel, the outer side of the outer glass panel is typically less hot than the inner side of the inner glass panel. Consequently, a significant amount of energy is consumed to remove ice and snow from the outer side of the outer glass panel.

[0004] EP 2 718 098 B1 discloses a composite glass plate having a heatable first coating and a second coating, wherein the second coating has a low emissivity. US 2009 / 0104385 A1 discloses a composite glass plate having an anti-reflective coating and a coating having other functions.

[0005] The object of the present invention is to provide a composite glass plate that is electrically heatable and wherein the heating function is improved.

[0006] According to the invention, the objective is achieved by the composite glass plate according to claim 1 and the method according to claim 15. Advantageous embodiments of the invention are derived from the dependent claims.

[0007] The present invention relates to a composite glass plate, which comprises at least an outer glass plate having an outer surface and an inner space side surface, an inner glass plate having an outer surface and an inner space side surface, and at least one thermoplastic interlayer connecting the inner space side surface of the outer glass plate and the outer surface of the inner glass plate, forming a laminated stack sequence.

[0008] According to the present invention, the heatable element is applied directly to the inner space side surface of the outer glass plate or to the outer surface of the inner glass plate.

[0009] Furthermore, according to the present invention, the coating that reflects heat radiation is applied directly to the inner space side surface of the inner glass plate and / or the coating that reflects heat radiation is applied directly to the outer surface of the outer glass plate.

[0010] Composite glass panels are provided for separating interior spaces, particularly those of vehicles or buildings, from the external environment within window openings. The composite glass panel is a laminate and comprises first and second vitreous glass panels, referred to in this invention as an outer glass panel and an inner glass panel, and connected to each other by a thermoplastic interlayer. In this invention, the inner glass panel refers to the glass panel facing the interior space in its installation position. The outer glass panel refers to the glass panel facing the external environment in its installation position. In this invention, the interior space side surface (inner surface or inner side) is understood to refer to the surface of the glass panel facing the interior space in its installation position. In this invention, the outer surface (or outer side or outside) is understood to refer to the surface of the glass panel facing the external environment in its installation position.

[0011] The surface of a glass plate is usually referred to as follows: The outer surface of the outer glass panel is called Side I. The inner surface of the outer glass panel is called Side II. The outer surface of the inner glass panel is called Side III. The inner surface of the inner glass panel is called Side IV.

[0012] The inner space side surface II of the outer glass plate and the outer side surface III of the inner glass plate face each other and are connected to each other by means of at least one thermoplastic interlayer.

[0013] According to the present invention, a coating that reflects thermal radiation is applied directly to the inner space side surface IV of the inner glass plate and / or directly to the outer side surface I of the outer glass plate. Such a coating is known, for example, from WO2013 / 131667A1. The coating that reflects thermal radiation may also be referred to as a low emissivity coating, an emissivity-reducing coating, a thermal radiation-reducing coating, a low-E coating, or a low-E layer. Its function is to reflect thermal radiation, specifically infrared radiation with wavelengths longer than the infrared component of solar radiation.

[0014] The coating that reflects heat radiation is preferably extended on the entire internal space side surface IV of the inner glass plate and / or on the entire outer side surface I of the outer glass plate.

[0015] Alternatively, the coating that reflects heat radiation may extend only on a portion of the inner glass panel's internal space side IV and / or only on a portion of the outer glass panel's outer surface I.

[0016] In one embodiment, a protective layer is applied over a coating that reflects heat radiation. This optional protective layer serves to prevent corrosion and / or damage.

[0017] In a particularly advantageous embodiment of the invention, the heatable element is applied directly to the outer surface III of the inner glass plate and the heat-reflecting coating is applied directly to the inner space side surface IV of the inner glass plate.

[0018] In another advantageous embodiment of the invention, the heatable element is applied directly to the inner space side surface II of the outer glass plate and the heat-reflecting coating is applied directly to the inner space side surface IV of the inner glass plate.

[0019] In another advantageous embodiment of the invention, the heatable element is applied directly to the inner space side surface II of the outer glass plate and the heat-reflecting coating is applied directly to the outer side surface I of the outer glass plate.

[0020] In another advantageous embodiment of the invention, the heatable element is applied directly to the outer surface III of the inner glass plate and the heat-reflecting coating is applied directly to the outer surface I of the outer glass plate.

[0021] In another advantageous embodiment of the invention, the heatable element is applied directly to the outer surface III of the inner glass plate, the heat-reflecting coating is applied directly to the outer surface IV of the inner glass plate, and the heat-reflecting coating is applied directly to the outer surface I of the outer glass plate.

[0022] In another advantageous embodiment of the invention, the heatable element is applied directly to the inner space side surface II of the outer glass plate, the heat-reflecting coating is applied directly to the outer surface IV of the inner glass plate, and the heat-reflecting coating is applied directly to the outer surface I of the outer glass plate.

[0023] The arrangement of the heat-reflecting coating on the inner space side surface IV of the inner glass panel prevents the inner glass panel, which is heated by the heatable element, from radiating heat inwards. This reduces heat radiation dissipated into the interior space and heats the composite glass panel more effectively.

[0024] The arrangement of the heat-reflecting coating on the outer surface I of the outer glass panel prevents the outer glass panel, which is heated by the heat-generating element, from radiating heat outwards. This reduces heat radiation dissipated into the external environment and heats the composite glass panel more effectively.

[0025] The arrangement of the heat-reflecting coating on the inner space side surface IV of the inner glass plate and the heat-reflecting coating on the outer surface I of the outer glass plate can prevent the inward heat radiation of the inner glass plate heated by the heatable element and the outward heat radiation of the outer glass plate heated by the heatable element, thereby heating the composite glass plate particularly effectively and reducing heat radiation dissipation into the external environment or the internal space.

[0026] As described above, in the composite glass panel according to the invention, the heat radiation dissipated into the internal space is reduced by the heat-reflecting coating on the inner space side surface IV of the inner glass panel and / or the heat radiation dissipated into the external environment is reduced by the heat-reflecting coating on the outer surface I of the outer glass panel, thereby heating the composite glass panel more effectively than the composite glass panel according to the prior art. For the same heating effect, the composite glass panel according to the invention consumes less electricity than the composite glass panel according to the prior art. Achieving the same heating effect earlier or requiring less power to obtain the same heating effect within a certain time is also possible.

[0027] The heat-reflecting coating on the inner space side surface IV of the inner glass panel and / or on the outer space side surface I of the outer glass panel reduces heat radiation emitted from the vehicle's interior space to the external environment at cold external temperatures, and reduces heat or cold radiation into the vehicle's interior space. This reduces the so-called... Cold wall effect .

[0028] Heating elements can be formed as a heatable coating.

[0029] The heatable coating preferably comprises a layer system having at least one metal layer, particularly at least one metallic silver layer, embedded between dielectric oxide layers or nitride layers.

[0030] Alternatively, the heating element can be formed as at least one heating wire, preferably a tungsten wire.

[0031] In a particularly preferred embodiment, the heating element is formed as at least one tungsten filament. That is, the heating element is particularly preferably formed as a tungsten filament or an arrangement of multiple tungsten filaments.

[0032] For example, the heating element can also be formed in the form of printed silver wire.

[0033] The heating element, formed as a heatable coating, preferably extends on the entire inner space side surface II of a circumferential, frame-like uncoated area of ​​the outer glass plate, minus a width of 1 mm to 50 cm, preferably 2 mm to 20 cm, and particularly preferably 1 cm to 20 cm, or on the entire outer surface III of a circumferential, frame-like uncoated area of ​​the inner glass plate, minus a width of 1 mm to 50 cm, preferably 2 mm to 20 cm, and particularly preferably 1 cm to 20 cm. The uncoated edge areas are tightly sealed by bonding with a thermoplastic interlayer. This advantageously protects the heatable coating from damage and corrosion, particularly originating from the edges of the composite glass plate.

[0034] Alternatively, the heatable coating may extend over the entire inner space side surface II of the outer glass panel or over the entire outer surface III of the inner glass panel.

[0035] Optionally, the purpose is to ensure that electromagnetic radiation transmission through the composite glass plate in local areas serving as communication-, sensor-, or camera windows does not have a heatable coating and / or a coating that reflects heat radiation.

[0036] Both the heatable coating and the heat-reflecting coating are transparent functional coatings that provide properties for altering the surface of the glass plate. A coating is considered transparent in the sense of the invention if its average transmittance in the visible spectrum is at least 70%, preferably at least 80%, and thus substantially does not restrict visibility through the glass plate of a vehicle. Both the heatable coating and the heat-reflecting coating are, in particular, thin-film coatings, i.e., formed as thin layers or stacks of thin layers.

[0037] A heatable coating is a conductive coating that allows current to flow through it when it comes into electrical contact. Conductivity is provided specifically by forming one or more monolayers of the coating as conductive layers, for example, based on a metal, particularly silver, or for example, gold, aluminum, or copper. In addition to at least one conductive layer, there is usually a dielectric layer, which serves, for example, as an antireflective layer to improve light transmittance, as an adapting layer to improve the crystallinity of the conductive layer, or as a smoothing layer to improve the surface structure of the layers placed thereon. Common materials for dielectric layers include silicon nitride, titanium oxide, aluminum nitride, tin oxide, zinc oxide, tin-zinc mixed oxides, and silicon oxide.

[0038] The thickness of the conductive layer in the heatable coating is preferably from 5 nm to 50 nm, and particularly preferably from 8 nm to 25 nm. Within this range of conductive layer thickness, high transmittance in the visible spectrum and particularly advantageous electrical conductivity are achieved.

[0039] Typically, at least one dielectric layer is disposed between two adjacent conductive layers of the heatable coating. Preferably, another dielectric layer is disposed below the first conductive layer and / or above the last conductive layer. The dielectric layer comprises at least one monolayer of dielectric material, such as a nitride like silicon nitride or an oxide like aluminum oxide. However, the dielectric layer may also comprise multiple monolayers, such as a monolayer of dielectric material, a smoothing layer, an adapter layer, a barrier layer, and / or an antireflective layer. The thickness of the dielectric layer is, for example, from 10 nm to 200 nm.

[0040] This layer structure is typically obtained through a series of deposition processes, which are carried out using vacuum methods such as magnetic field-assisted cathodic sputtering.

[0041] Heated coatings are known, for example, from WO2013 / 104438 A1, WO2013 / 104439 A1 or WO 2016 / 020113A1.

[0042] For example, the heatable coating may also be one of the conductive coatings described in WO 2019 / 179683 A1 or WO 2020 / 094422 A1.

[0043] The coating that reflects thermal radiation preferably comprises a functional layer containing a transparent conductive oxide (TCO), preferably indium tin oxide (ITO), tin oxide doped with antimony or fluorine, and / or zinc oxide doped with gallium and / or aluminum (ZnO:Ga, or ZnO:Al), with indium tin oxide being the most preferred. However, the functional layer may also contain other conductive oxides, such as fluorine-doped tin oxide (SnO2:F), antimony-doped tin oxide (SnO2:Sb), indium-zinc mixed oxide (IZO), gallium-doped or aluminum-doped zinc oxide, niobium-doped titanium oxide, cadmium stannate, and / or zinc stannate. This results in particularly good emissivity and flexibility of the coating according to the invention. The refractive index of the functional layer material is preferably from 1.7 to 2.5.

[0044] Indium tin oxide (ITO) is preferably deposited together with an ITO target using magnetic field-assisted cathode sputtering. The target preferably comprises 75% to 95% by weight of indium oxide and 5% to 25% by weight of tin oxide, as well as a mixture resulting from the manufacturing process. The deposition of tin-doped ITO is preferably carried out under a protective gas atmosphere, such as argon. A small proportion of oxygen may also be added to the protective gas, for example, to improve the uniformity of the functional layer.

[0045] Alternatively, preferably, the target material may contain at least 75% to 95% by weight of indium and 5% to 25% by weight of tin. In this case, the deposition of indium tin oxide is preferably carried out with oxygen added as a reactive gas during cathode sputtering.

[0046] Coatings that reflect thermal radiation typically also include a dielectric layer, particularly formed of dielectric oxides or nitrides such as ZnO, SnZnO, AlN, TiO2, SiO2, or Si3N4. Layers of reflective conductive oxides provide anti-reflection by using additional dielectric layers above and below to ensure sufficiently low reflection on the inner side.

[0047] The emissivity of the glass plate according to the invention can be influenced by the thickness of the functional layer of the heat-reflecting coating. The thickness of this functional layer is preferably 40 nm to 200 nm, particularly preferably 60 nm to 150 nm, and very particularly preferably 65 nm to 85 nm, for example, about 75 nm. Within this thickness range, particularly advantageous emissivity values ​​and the ability of the heat-reflecting coating to withstand mechanical deformation (such as bending or prestressing) are achieved without damage.

[0048] The emissivity of the composite glass panel according to the invention on the interior space side is preferably less than or equal to 50%, particularly preferably 10% to 50%, and very particularly preferably 10% to 35%. Here, the emissivity on the interior space side refers to a measure of how much heat radiation the glass panel emits at its installation location into the interior space (e.g., a building or vehicle) compared to an ideal thermal radiator (blackbody). In the context of this invention, emissivity is understood to refer to the normal emissivity at 283 K according to standard EN 12898.

[0049] In one embodiment of the invention, the heatable element, as described above, can be formed as a heatable coating or as a heatable wire, connected to a voltage source to conduct current through the heatable element, thereby heating it. The voltage is particularly considered to be the on-board voltage common in the transportation sector, such as 12 V to 14 V, or, in the case of electric vehicles, typically up to 500 V. For connection to the voltage source, the heatable element preferably has a busbar that can be connected to the electrodes of the voltage source. For example, the busbar can be formed as a printed and burned-in conductor, typically in the form of a burned-in screen-printed paste with glass frit and silver particles. However, alternatively, strips of conductive film can be used as busbars, placed or bonded to the ends of the heatable coating or heatable wire, such as copper or aluminum foil. Typically, two busbars are located near two opposing edges of the composite glass plate, such as the upper and lower edges.

[0050] The thermoplastic interlayer is formed from one or more thermoplastic polymer films. 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 formed based on the materials mentioned above, but may contain other components, such as plasticizers, colorants, IR or UV absorbers, preferably in proportions of less than 50%.

[0051] Individual polymer films, particularly PVB films, preferably have a thickness of about 0.025 mm (25 μm) to 1 mm, especially 25 μm to 125 μm and 0.3 mm to 1 mm, such as 50 μm, 100 μm, 0.38 mm, or 0.76 mm. Other properties of the composite vitreous glass can be affected by the thickness of the film. For example, thicker PVB films improve sound insulation, especially when they contain an acoustically effective core; the burglarproof performance of the composite vitreous glass increases; and it also increases protection against ultraviolet radiation (UV protection).

[0052] In a favorable design, the thermoplastic interlayer is formed from one or more polyvinyl butyral films.

[0053] In addition, the thermoplastic interlayer can be a functional interlayer, particularly an interlayer with sound damping properties, an at least partially colored interlayer, and / or an at least partially colored interlayer.

[0054] The outer and / or inner glass panels may be formed of glass and / or polymers, preferably soda-lime glass, alkali metal aluminosilicate glass, polycarbonate, and / or polymethyl methacrylate. In a particularly preferred design, both the outer and inner glass panels are made of glass.

[0055] Suitable glass sheets include those from Saint-Gobain known by the trade names Planiclear and Planilux (each a clear glass), VG10, VG20, VG40, or TSANx, TSA3+, TSA4+, where the VG series is gray tinted glass and the TSA series is green tinted glass.

[0056] The outer glass plate and / or inner glass plate preferably have a thickness of 0.5 mm to 4 mm, and particularly preferably a thickness of 1.6 mm to 2.1 mm. The outer glass plate and / or inner glass plate may have a constant thickness or may be slightly wedge-shaped.

[0057] The outer glass pane, inner glass pane, and at least one thermoplastic interlayer can be transparent and colorless, but can also be tinted or colored. In a preferred design, the total transmittance through the composite glass is greater than 70%. The term total transmittance refers to the method for testing the light transmittance of a motor vehicle glass pane as determined by ECE-R 43, Annex 3, Section 9.1. The outer and inner glass panes can be independently unstressed, partially prestressed, or prestressed. If at least one of the glass panes is prestressed, this can be thermal or chemical prestressing.

[0058] Composite glass panels are preferably curved in one or more directions in space, as is common for glass panels used in motor vehicles, with typical radii of curvature ranging from about 10 cm to about 40 m. However, composite glass panels can also be flat, for example, when they are provided as glass panels for buses, trains, or tractors.

[0059] The outer glass plate, the inner glass plate, and at least one thermoplastic intermediate layer may have suitable coatings known per se, such as anti-reflective coatings, non-stick coatings, scratch-resistant coatings, or photocatalytic coatings.

[0060] The heatable element can be connected to a voltage source as described above. According to the invention, the composite glass plate is therefore also as described above, wherein the heatable element is connected to a voltage source.

[0061] The composite glass panel according to the invention may further include an overprint, particularly made of dark, preferably black, enamel. The overprint is particularly peripheral, i.e., a frame-like overprint. The peripheral overprint primarily serves as UV protection for the assembly adhesive of the composite glass panel. The overprint can be opaque and fully formed. The overprint can also be at least partially translucent, for example, formed as a dot grid, strip grid, or square grid. Alternatively, the overprint can also have a gradient, for example, from opaque to translucent. The overprint is typically applied to the inner space side surface of the outer glass panel or the inner space side surface of the inner glass panel, wherein the overprint is preferably applied to the glass panel surface on which the heat-reflective coating and the heat-reflecting coating of the composite glass panel according to the invention are not disposed.

[0062] The present invention also relates to a method for manufacturing a composite glass plate, comprising at least the following steps: a) Provide an outer glass plate having an outer surface I and an inner space side surface II, an inner glass plate having an outer surface III and an inner space side surface IV, and at least one thermoplastic intermediate layer, wherein a heatable element is applied directly to the inner space side surface II of the outer glass plate or to the outer surface III of the inner glass plate, and a heat-reflecting coating is applied directly to the inner space side surface IV of the inner glass plate and / or a heat-reflecting coating is applied directly to the outer surface I of the outer glass plate; b) The outer glass plate, at least one thermoplastic interlayer and the inner glass plate are stacked in such a way that the inner space side surface II of the outer glass plate and the outer side surface III of the inner glass plate face each other and at least one thermoplastic interlayer is disposed between the outer glass plate and the inner glass plate. c) The outer glass plate and the inner glass plate are laminated together to form a composite glass plate by means of at least one thermoplastic interlayer.

[0063] Lamination is preferably carried out under the influence of heat, vacuum, and / or pressure. Methods known per se can be used for lamination, such as autoclave methods, vacuum bag methods, vacuum ring methods, calendering methods, vacuum laminators, or combinations thereof.

[0064] The coating that reflects thermal radiation is preferably applied by physical vapor deposition (PVD) to the inner space side surface IV of the inner glass plate and / or to the outer side surface I of the outer glass plate, particularly preferably by cathodic sputtering (“sputtering”), and very particularly preferably by magnetic field-assisted cathodic sputtering.

[0065] If the heatable element is formed as a heatable coating, it is preferably applied to the inner space side surface II of the outer glass plate or to the outer surface III of the inner glass plate by physical vapor deposition (PVD), particularly preferably by cathodic sputtering (“sputtering”), and very particularly preferably by magnetic field-assisted cathodic sputtering.

[0066] Needless to say, the busbars (buses) required to connect the heatable elements to the voltage source are applied before the lamination step.

[0067] If the composite glass sheet is to be curved, the outer and inner glass sheets are preferably subjected to a bending process before lamination and preferably after any possible coating process. Preferably, the outer and inner glass sheets are bent together (i.e., simultaneously and using the same tool) in a consistent manner, as this ensures that the shapes of the glass sheets are optimally matched to each other for the subsequent lamination. Typical temperatures for the glass bending process are, for example, 500°C to 700°C.

[0068] In one embodiment of the method according to the invention, the coating that reflects thermal radiation is applied to the inner space side surface (IV) of the inner glass plate after the lamination process and / or the coating that reflects thermal radiation is applied to the outer side surface (I) of the outer glass plate after the lamination process.

[0069] The composite glass panel according to the invention can be used in water, land, or air vehicles, preferably as windshields, and particularly preferably as windshields of motor vehicles, especially passenger cars. Alternatively, the composite glass panel according to the invention can also be used in building glazing or some other building glazing.

[0070] Various design schemes of the present invention can be implemented individually or in any combination. In particular, without departing from the scope of the present invention, the features mentioned above and explained below can be used not only in the given combinations, but also in other combinations or individually.

[0071] The invention will now be explained in more detail with reference to embodiments, wherein reference is made to the accompanying drawings. These drawings are not intended to limit the invention in any way. They are shown in simplified, non-scaled illustrations: Figure 1 A plan view of a design scheme for a composite glass plate according to the present invention. Figure 2 Passing through the composite glass plate according to the invention Figure 1 The cross-section of the design scheme shown. Figure 3 Through a cross-section of another design of the composite glass plate according to the invention, Figure 4 Through a cross-section of another design of the composite glass plate according to the invention, Figure 5 Through a cross-section of another design of the composite glass plate according to the invention, Figure 6 Through a cross-section of another design of the composite glass plate according to the invention, Figure 7 A cross-section through another design of the composite glass plate according to the invention, and Figure 8 A cross-section through another design of the composite glass plate according to the invention.

[0072] Figure 1 A plan view of a design scheme for the composite glass plate 1 according to the present invention is shown. Figure 2 It shows the passage along the section line XX' Figure 1 The cross-section of the composite glass plate shown is illustrated. Figure 1 and 2As can be seen, the composite glass panel 1 has an upper edge O, a lower edge U, and two side edges S. The composite glass panel 1 includes an outer glass panel 2 and an inner glass panel 3, which are laminated together and permanently bonded by a thermoplastic interlayer 4. The composite glass panel 1 is provided, for example, as a windshield for a passenger vehicle, wherein an outer glass panel 2 is provided for facing the external environment and an inner glass panel 3 is provided for facing the interior space of the vehicle. The outer glass panel 2 has an outer surface I and an inner space side surface II. The inner glass panel 3 has an outer surface III and an inner space side surface IV. Outer surfaces I and III face the external environment in the installation position, and inner space side surfaces II and IV face the interior space of the vehicle in the installation position. The inner space side surface II of the outer glass panel 2 and the outer surface III of the inner glass panel 3 face each other. The outer glass panel 2 comprises, for example, soda-lime glass and has a thickness of, for example, 2.1 mm. The inner glass panel 3 comprises, for example, soda-lime glass and has a thickness of, for example, 1.6 mm. The thermoplastic interlayer 4 comprises or is composed of polyvinyl butyral (PVB) and has a thickness of, for example, 0.76 mm. It goes without saying that the composite glass plate 1 according to the invention may also have other dimensions to match their respective individual cases, particularly other layer thicknesses of the outer glass plate 2, the inner glass plate 3, and the thermoplastic interlayer 4.

[0073] A heatable element 5 in the form of a heatable coating is disposed on the outer surface III of the inner glass plate 3. The heatable coating is constructed, for example as described in WO 2020 / 094422 A1, and comprises at least four conductive silver layers, each disposed between two dielectric layers or layer sequences, wherein the total thickness of all conductive silver layers is at most 30 nm, and wherein at least one of the conductive silver layers has a thickness of at most 5 nm.

[0074] A heat-reflecting coating 6 is disposed on the inner space side surface IV of the inner glass plate 3. The heat-reflecting coating 6 includes, for example, a functional ITO layer with a thickness of 60 nm to 150 nm and additional dielectric layers above and below the functional layer, particularly made of Al-doped SiO2 and Si3N4.

[0075] The heat-reflecting coating 6 reduces the amount of heat radiation emitted by the heatable element 5, which is formed as a heatable coating, from penetrating the composite glass panel into the vehicle's interior space. Furthermore, in low external temperatures, the heat-reflecting coating 6 also reduces the amount of heat radiation emitted from the vehicle's interior space.

[0076] The heating element 5 can be connected to a voltage source via a busbar (bus). Figure 1 and 2 (Not shown in the image).

[0077] Figure 3A cross-section of another embodiment of the composite glass plate 1 according to the present invention is shown. Figure 3 Composite glass plate 1 shown in cross-section and Figure 2 The only difference in the composite glass plate 1 shown in cross-section is that the heatable element 5, which is formed as a heatable coating, is not applied to the outer surface III of the inner glass plate 3, but to the inner space side surface II of the outer glass plate 2.

[0078] Figure 4 A cross-section of another embodiment of the composite glass plate 1 according to the present invention is shown. Figure 4 The composite glass panel 1, shown in cross-section, includes an outer glass panel 2 and an inner glass panel 3, which are laminated together and permanently bonded together by a thermoplastic interlayer 4. The composite glass panel 1 is provided, for example, as a windshield for a passenger vehicle, wherein an outer glass panel 2 is provided for facing the external environment and an inner glass panel 3 is provided for facing the interior space of the vehicle. The outer glass panel 2 has an outer surface I and an inner space side surface II. The inner glass panel 3 has an outer surface III and an inner space side surface IV. Outer surfaces I and III face the external environment in the installation position, and inner space side surfaces II and IV face the interior space of the vehicle in the installation position. The inner space side surface II of the outer glass panel 2 and the outer surface III of the inner glass panel 3 face each other. The outer glass panel 2 comprises, for example, soda-lime glass and has a thickness of, for example, 2.1 mm. The inner glass panel 3 comprises, for example, soda-lime glass and has a thickness of, for example, 1.6 mm. The thermoplastic interlayer 4 comprises or is composed of polyvinyl butyral (PVB) and has a thickness of, for example, 0.76 mm. It goes without saying that the composite glass plate 1 according to the present invention may also have other dimensions to match their respective individual cases, especially other layer thicknesses of the outer glass plate 2, the inner glass plate 3 and the thermoplastic intermediate layer 4.

[0079] A heatable element 5 in the form of a heatable coating is arranged on the inner surface II of the outer glass plate 2.

[0080] The heatable coating is constructed as described in WO 2020 / 094422 A1 and comprises at least four conductive silver layers, each disposed between two dielectric layers or layer sequences, wherein the total thickness of all conductive silver layers is at most 30 nm, and wherein at least one of the conductive silver layers has a thickness of at most 5 nm.

[0081] A heat-reflecting coating 6 is disposed on the outer surface I of the outer glass plate 2. The heat-reflecting coating 6 includes, for example, a functional ITO layer with a thickness of 60 nm to 150 nm and additional dielectric layers above and below the functional layer, particularly made of Al-doped SiO2 and Si3N4.

[0082] The heat-reflecting coating 6 reduces the heat radiation emitted by the heatable element 5, which is formed as a heatable coating, from radiating outward through the composite glass plate. On the other hand, when the external temperature is low, the heat-reflecting coating 6 also reduces the heat radiation emitted from the interior space of the vehicle.

[0083] Figure 5 A cross-section of another embodiment of the composite glass plate 1 according to the present invention is shown. Figure 5 Composite glass plate 1 shown in cross-section and Figure 4 The only difference between the composite glass plates shown in the cross section is that the heating element 5, which is formed as a heatable coating, is not arranged on the inner space side surface II of the outer glass plate 2, but on the outer surface III of the inner glass plate 3.

[0084] Figure 6 A cross-section of another embodiment of the composite glass plate 1 according to the present invention is shown. Figure 6 Composite glass plate 1 shown in cross-section and Figure 2 The only difference in the composite glass plate shown in the cross section is that an additional coating 6 for reflecting heat radiation is applied to the outer surface I of the outer glass plate 2.

[0085] Figure 7 A cross-section of another embodiment of the composite glass plate 1 according to the present invention is shown. Figure 7 Composite glass plate 1 shown in cross-section and Figure 3 The only difference in the composite glass panel shown in cross-section is that an additional coating 6 for reflecting heat radiation is applied to the outer surface I of the outer glass panel 2.

[0086] Figure 8 The figure shows a cross-section of another embodiment of the composite glass plate 1 according to the present invention. Figure 8 The embodiment of the composite glass plate 1 according to the present invention, shown in cross-section, is shown in the figure. Figure 2 The only difference in the embodiment shown is that the heatable element 5 is formed as an arrangement of heatable wires. The heatable wires are, for example, tungsten wires with a diameter of 10 μm to 33 μm. For example, it can be multiple wires arranged in parallel to each other or a single wire extending in a serpentine pattern on the outer surface III of the inner glass plate 3.

[0087] List of reference numerals 1. Composite glass panel 2. Outer glass panel 3. Inner glass plate 4. Thermoplastic interlayer 5. Heating element 6. Coatings that reflect heat radiation XX' section line O upper edge U-shaped lower edge S side edge

Claims

1. A composite glass plate (1), comprising at least a stacked sequence of laminates consisting of: - An outer glass panel (2) having an outer surface (I) and an inner space side surface (II), - An inner glass plate (3) having an outer surface (III) and an inner space side surface (IV), and - At least one thermoplastic interlayer (4) connecting the inner space side surface (II) of the outer glass plate (2) to the outer side surface (III) of the inner glass plate (3), in - The heating element (5) is applied directly to the inner space side surface (II) of the outer glass plate (2) or to the outer surface (III) of the inner glass plate (3), and - Apply the heat-reflecting coating (6) directly to the inner space side surface (IV) of the inner glass plate (3) and apply the heat-reflecting coating (6) directly to the outer surface (I) of the outer glass plate (2).

2. The composite glass plate (1) according to claim 1, wherein the heatable element (5) is formed as a heatable coating.

3. The composite glass plate (1) according to claim 2, wherein the heatable coating comprises a layer system having at least one metal layer embedded between dielectric oxide layers or nitride layers.

4. The composite glass plate (1) according to claim 3, wherein the heatable coating comprises a layer system having at least one metallic silver layer.

5. The composite glass plate (1) according to claim 1, wherein the heatable element (5) is formed as at least one heatable filament.

6. The composite glass plate (1) according to claim 5, wherein the heatable element (5) is formed as at least one heatable tungsten filament.

7. The composite glass plate (1) according to any one of claims 1 to 6, wherein the coating (6) for reflecting thermal radiation comprises a transparent conductive oxide.

8. The composite glass plate (1) according to claim 7, wherein the coating (6) for reflecting thermal radiation comprises indium tin oxide, tin oxide doped with antimony or fluorine and / or zinc oxide doped with aluminum and / or zinc oxide doped with gallium.

9. The composite glass plate (1) according to claim 7, wherein the coating (6) for reflecting heat radiation is composed of indium tin oxide.

10. The composite glass plate (1) according to any one of claims 1 to 6, wherein the thickness of the outer glass plate (2) and / or the inner glass plate (3) is 0.5 mm to 4 mm.

11. The composite glass plate (1) according to claim 10, wherein the thickness of the outer glass plate (2) and / or the inner glass plate (3) is 1.6 mm to 2.1 mm.

12. The composite glass plate (1) according to any one of claims 1 to 6, wherein the heatable element (5) is connected to a voltage source.

13. A method for manufacturing a composite glass plate (1) according to any one of claims 1 to 12, wherein at least a) Provide an outer glass plate (2) having an outer surface (I) and an inner space side surface (II), an inner glass plate (3) having an outer surface (III) and an inner space side surface (IV), and at least one thermoplastic intermediate layer (4), wherein a heatable element (5) is applied directly to the inner space side surface (II) of the outer glass plate (2) or to the outer surface (III) of the inner glass plate (3), and a heat-reflecting coating (6) is applied directly to the inner space side surface (IV) of the inner glass plate (3) and to the outer surface (I) of the outer glass plate (2); b) The outer glass plate (2), at least one thermoplastic intermediate layer (4) and the inner glass plate (3) are stacked in such a way that the inner space side surface (II) of the outer glass plate (2) and the outer surface (III) of the inner glass plate (3) face each other and the at least one thermoplastic intermediate layer (4) is disposed between the outer glass plate (2) and the inner glass plate (3). c) The outer glass plate (2) and the inner glass plate (3) are laminated together to form a composite glass plate (1) by means of at least one thermoplastic interlayer (4).

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