Panel with a radiance-reducing coating

Abstract

The invention relates to a panel (10) comprising a substrate (1) and a reduced emissivity coating (2) located on a first surface (IV) of the substrate (1), said coating comprising at least, in the specified order, starting from said substrate (1): • a functional layer (2.1) based on a transparent conductive oxide, • a first optical low-refractive layer (2.2) having a refractive index of less than or equal to 1.6, • a top layer (2.3) having a thickness of between 1 nm and 20 nm, wherein said top layer (2.3) is formed on the basis of silicon, and wherein said first optical low-refractive layer (2.2) is arranged directly adjacent to the functional layer (2.1).

Description

[0001] The present invention relates to a panel having a radiation-reducing coating, a heat-treated panel, a laminated panel, a method for producing said panel or heat-treated panel, and the use of said panel or heat-treated panel.

[0002] Glass panels with transparent conductive coatings are known. Therefore, glass panels can be functionalized without significantly obstructing the view through the panel. Such coatings are used, for example, as heat-reflective coatings or heat radiation-reflecting coatings (so-called low-e radiation coatings or low-E coatings) on window panels of vehicles or buildings.

[0003] In the high temperatures of summer and under intense direct sunlight, the interior of vehicles or buildings can heat up dramatically. On the other hand, if the outside temperature is lower than the inside temperature (especially in winter), the cold panels act as heat sinks, which can be uncomfortable. The interior must also be strongly heated to prevent cooling through the window panels.

[0004] The anti-radiation coating reflects a significant portion of solar radiation, particularly in the infrared range, resulting in reduced internal temperature rise during the summer. The coating also reduces long-wave heat radiation radiated inwards from heated panels. In winter, when external temperatures are low, the coating prevents internal heat from radiating to the external environment.

[0005] To achieve optimal functionality, the anti-radiation coating must be applied to the inner surface of the panel, i.e., between the interior and the panel body. There, the coating is exposed to the atmosphere, which precludes the use of easily corroded coatings, such as silver-based coatings. Coatings based on transparent conductive oxides (TCOs), such as indium tin oxide (ITO), have proven effective as conductive coatings on exposed surfaces due to their corrosion resistance and good conductivity. Such coatings are known, for example, from EP 2 141 135 A1, WO 2010 / 115558 A1, and WO 2011 / 105991 A1.

[0006] WO 2018 / 206236A1 discloses a laminated panel with a conductive layer that has thermal radiation reflective properties, wherein fingerprints are less visible on the conductive layer due to its special layer structure.

[0007] WO 2013 / 132176 A2 discloses an assembled glass unit for use in the building sector, having an ITO-based conductive layer, wherein the coating is specifically designed to reduce moisture condensation on the assembled glass unit.

[0008] WO 2015 / 055944 A1 relates to a method for producing a material comprising a glass or glass-ceramic film. The glass or ceramic film is at least partially coated on at least one surface with a film stack, the film stack being free of a silver film and containing at least one conductive transparent oxide film and a thin homogenizing film. The homogenizing film is composed of a metal, a metal carbide, or a metal nitride other than aluminum nitride.

[0009] FR 2 963 343 A1 discloses an assembly glass having a glass substrate on one side thereof having a layer composed of a thin film stack, the thin film stack comprising, starting from the substrate, a transparent conductive oxide layer, an intermediate layer with a refractive index in the range of 1.40 to 1.55, and a titanium oxide-based photocatalytic layer.

[0010] WO 2016 / 198901 A1 discloses an assembled glass for minimizing or preventing bird collisions with windows or other assembled glass, wherein the assembled glass comprises at least one substrate on which a UV-reflective coating is deposited in a patterned arrangement, and the UV-reflective coating comprises a plurality of stripes, each of which has a thickness varying by 10 nm or less per 1 mm width. The UV-reflective coating comprises titanium dioxide, and an anti-reflective coating may be disposed between the substrate and the UV-reflective coating. The anti-reflective coating may comprise a first layer (containing tin oxide), a second layer (containing silicon oxide), a third layer (containing fluorinated tin oxide), and a fourth layer (containing silicon oxide).

[0011] EP 1 518 838 A1 discloses a glass article comprising a transparent heat-resistant glass plate and a visible light shielding layer on its surface, wherein the glass article has an average visible light transmittance of 0.03-15% at wavelengths of 380-780 nm and an average infrared reflectance of at least 50% at wavelengths of 1000-2500 nm.

[0012] FR 2 973 023 A1 discloses a multilayer assembled glass with thermal insulation properties, which is obtained by combining a plurality of glass substrates separated by a gas layer, wherein the front side of the first substrate forms the outer wall of the assembled glass and the back side of the last substrate defines the inner wall of the assembled glass, wherein the multilayer assembled glass comprises: a first low-emissivity layer stack containing at least one metallic functional layer, a second low-emissivity layer stack containing at least one transparent conductive oxide functional layer and a layer substantially composed of silicon oxide disposed above the functional layer composed of transparent conductive oxide.

[0013] If both oxide and nitride layers are used in the coating, special separation of the gases used to apply the oxide layer and the nitride layer is required during coating application. This results in increased production input and costs. Furthermore, the direct, continuous application of oxide and nitride layers carries the risk of forming an oxide-nitride mixed phase, which exhibits unpredictable optical properties.

[0014] Typically, after the anti-radiation coating is applied, the panel undergoes heat treatment and mechanical deformation. Panels used in motor vehicles, such as windshields, side panels, roof panels, or rear panels, are often curved and frequently prestressed or partially prestressed.

[0015] This invention aims to provide a panel with a radiation-reducing coating, characterized by its heat insulation effect. The panel should also be produced with minimal production input and low cost.

[0016] The object of the invention is achieved by the panel according to claim 1. Preferred embodiments arise from the dependent claims.

[0017] This invention relates to a panel comprising a substrate and a radiation-reducing coating located on a first surface of the substrate. The radiation-reducing coating comprises, starting from the substrate, at least in a specified order: • Functional layer based on transparent conductive oxide • A first optically low-refractive layer with a refractive index less than or equal to 1.6, and • Top layer with a thickness of 1nm to 20nm.

[0018] According to the present invention, the first optically low-refractive-index layer is disposed directly adjacent to the functional layer. This means that no additional layer is applied between the functional layer and the first optically low-refractive-index layer. According to the present invention, the top layer is formed based on silicon.

[0019] As described above, the panel according to the present invention comprises a substrate and a radiation-reducing coating located on a first surface of the substrate. Therefore, the panel according to the present invention is a coated panel.

[0020] An anti-radiation coating is a coating that reflects thermal radiation. Such coatings are often also called low-E coatings or anti-radiation coatings. Their function is to prevent heat (the IR component of solar radiation) from radiating into the interior, and also to prevent heat from radiating outwards. However, in principle, anti-radiation coatings can also perform other functions, such as acting as a heatable coating if they are heated by electrical contact due to the flow of current.

[0021] The panel according to the invention is preferably a window panel and is used, for example, to separate the interior and exterior environments in openings in a vehicle or building. The first surface of the substrate on which the anti-radiation coating is disposed is preferably the inner surface of the panel or the substrate. In the context of the invention, the inner surface is understood to mean the surface intended to face inwards when the panel is installed. This is particularly advantageous for interior thermal comfort. Under high external temperatures and solar radiation, the anti-radiation coating can particularly effectively, at least partially, reflect heat radiation radiated from the entire panel inwards. Under low external temperatures, the anti-radiation coating can effectively reflect heat radiation radiated from the interior, reducing the effect of the cold panel as a heat sink. Alternatively, the anti-radiation coating can also be disposed on the outer surface of the substrate. This can be particularly useful in the construction field, for example, as an anti-condensation coating on window panels.

[0022] Because the first low-refractive-index layer is arranged directly adjacent to the functional layer, the anti-radiation coating specifically eliminates the need for an additional nitride-based layer between the functional layer and the first low-refractive-index layer. Since no nitride material is used when applying the functional layer, the first low-refractive-index layer, and the top layer, gas separation is not required when applying the oxide layer and the nitride layer. Therefore, the panel according to the invention is characterized by being particularly easy, reliable, and cost-effective to manufacture compared to conventional panels with anti-radiation coatings.

[0023] The functional layer can contain, for example, indium tin oxide (ITO), aluminum zinc oxide (AZO), indium zinc oxide (IZO), gallium-doped tin oxide (GZO), fluorine-doped tin oxide (SnO2:F), antimony-doped tin oxide (SnO2:Sb), or niobium-doped titanium oxide (TiO2:Nb). In a particularly advantageous embodiment, the functional layer is formed based on indium tin oxide. This material achieves particularly good results, especially because of its low resistivity and low scattering in terms of thin-film resistance.

[0024] In a preferred embodiment, the thickness of the functional layer is from 30 nm to 200 nm, particularly preferably from 50 nm to 130 nm. This thickness range achieves exceptionally good thermal properties for the panel.

[0025] In a particularly advantageous embodiment, the first optically low-refractive-index layer is formed based on silicon oxide, which may be doped or undoped. Doped silicon oxide is particularly preferred, especially aluminum-doped, titanium-doped, zirconium-doped, or boron-doped silicon oxide. Particularly good results are achieved using these materials. These materials are inexpensive and easy to apply.

[0026] Preferably, the thickness of the first optical low-refractive-index layer is 30 nm to 200 nm, particularly preferably 50 nm to 200 nm. This thickness range is particularly suitable for achieving low absorption and high transmittance of visible light transmitted through the panel. Furthermore, by changing the thickness of the first optical low-refractive-index layer, the reflectivity of the panel to visible light can be adjusted particularly well. This allows, for example, the setting of particularly low visible light reflectivity on the panel, which is particularly desirable when the panel is used as the top plate of a motor vehicle.

[0027] As mentioned above, the top layer is formed based on silicon; in other words, it is based on silicon.

[0028] If a layer is formed "based on" a certain material, then it is mainly composed of that material, and in particular, essentially composed of that material, except for any impurities or doping.

[0029] The top layer is preferably composed of doped or undoped silicon. Particularly preferred is zirconium-doped silicon, titanium-doped silicon, hafnium-doped silicon, or aluminum-doped silicon. Very particularly preferred is aluminum-doped silicon. A top layer composed of the above materials is particularly suitable for achieving low absorption and high transmittance of visible light transmitted through the panel. Furthermore, this ensures adequate protection of the functional layer during heat treatment, thereby particularly preventing excessive oxidation of the transparent conductive oxides of the functional layer.

[0030] The top layer is preferably the uppermost layer of the anti-radiation coating; that is, it is the layer with the greatest distance from the substrate among the layers of the anti-radiation coating.

[0031] The top layer preferably has a thickness of 2 nm to 15 nm, and particularly preferably 3 nm to 14 nm. This thickness range is particularly suitable for achieving low absorption and high transmittance of visible light transmitted through the panel. These thicknesses of the top layer also ensure adequate protection of the functional layers during heat treatment, thereby particularly preventing excessive oxidation of the transparent conductive oxides of the functional layers.

[0032] In a particularly advantageous embodiment, the anti-radiation coating does not contain any additional layers. This embodiment has the advantage of simplifying the manufacturing process. Therefore, in a particularly advantageous embodiment of the panel according to the invention, the panel comprises a substrate and an anti-radiation coating on a first surface of the substrate, the anti-radiation coating consisting, starting from the substrate, in a specified order of a functional layer based on a transparent conductive oxide, a first optically low refractive index layer less than or equal to 1.6, and a top layer with a thickness of 1 nm to 20 nm, wherein the top layer is formed based on silicon.

[0033] Alternatively, the anti-radiation coating may include additional layers. In a particularly advantageous embodiment, the anti-radiation coating also includes an optically high-refractive-index layer with a refractive index greater than or equal to 1.9. The optically high-refractive-index layer is located at a smaller distance from the substrate compared to the functional layer.

[0034] In this embodiment, the optically high refractive layer acts as a dielectric barrier layer to prevent alkali diffusion. If the substrate is a glass substrate, the optically high refractive layer reduces or prevents alkali ions from diffusing from the glass substrate into the anti-radiation coating. Alkali ions can adversely affect the properties of the coating. Furthermore, the combination of the optically high refractive layer and the first optically low refractive layer advantageously helps to regulate the coloration and reflection of the entire layer structure. Particularly good results are obtained if the refractive index of the optically high refractive layer is between 1.9 and 2.5. The optically high refractive layer preferably contains oxides, nitrides, or carbides, preferably oxides, nitrides, or carbides of tungsten, chromium, niobium, tantalum, zirconium, hafnium, titanium, silicon, or aluminum, such as oxides like WO3, Nb2O5, Bi2O3, TiO2, Ta2O5, ZrO2, HfO2, SnO2, or ZnSnO. x Or nitrides such as AlN, TiN, TaN, ZrN, or NbN. The optically high refractive index layer particularly preferably contains silicon nitride (Si3N4), which achieves particularly good results. Silicon nitride may have dopants, and in preferred improvements, it is doped with aluminum (Si3N4:Al), titanium (Si3N4:Ti), zirconium (Si3N4:Zr), or boron (Si3N4:B). The optically high refractive index layer is preferably the underlayer of the radiation-reducing coating; that is, it is in direct contact with the substrate surface, where it can best perform its function. Simultaneously, the optically high refractive index layer also acts as an adhesion layer for other layers on the substrate. Preferably, the thickness of the optically high refractive index layer is 10 nm to 50 nm, particularly preferably 20 nm to 40 nm.

[0035] In another preferred embodiment, the anti-radiation coating further comprises a second optically low-refractive-index layer with a refractive index less than or equal to 1.6. The second optically low-refractive-index layer is located at a smaller distance from the substrate compared to the functional layer. Particularly preferably, the anti-radiation coating comprises both an optically high-refractive-index layer and a second optically low-refractive-index layer. In this case, the second optically low-refractive-index layer is located at a larger distance from the substrate compared to the optically high-refractive-index layer. In these embodiments, the second optically low-refractive-index layer acts as a dielectric anti-reflective layer. The second optically low-refractive-index layer reduces reflectivity, thereby increasing the transparency of the panel and preferably ensuring a neutral color effect. The second optically low-refractive-index layer preferably contains an oxide or fluoride, particularly preferably silicon oxide, magnesium fluoride, or calcium fluoride. Silicon oxide is very particularly preferred. The silicon oxide may have dopants, and is preferably doped with aluminum (SiO2:Al), boron (SiO2:B), titanium (SiO2:Ti), or zirconium (SiO2:Zr). The thickness of the second optically low-refractive-index layer is preferably from 5 nm to 40 nm, and more preferably from 10 nm to 35 nm.

[0036] Particularly preferably, the anti-radiation coating does not contain any additional layers other than the aforementioned high-refractive-index layer with a refractive index greater than or equal to 1.9 and the aforementioned second low-refractive-index layer with a refractive index less than or equal to 1.6. The anti-radiation coating particularly does not have any additional functional layers based on transparent conductive oxides.

[0037] In a preferred embodiment, the first low-refractive-index layer is arranged directly adjacent to the top layer.

[0038] Unless otherwise stated, the description of layer thickness or thickness refers to the geometric thickness of the layer.

[0039] The inner emissivity of the panel according to the invention is preferably less than or equal to 45%, particularly preferably less than or equal to 35%, and very particularly preferably less than or equal to 30%. Here, inner emissivity is a measure of how much thermal radiation the panel radiates into the interior (e.g., the interior of a building or vehicle) compared to an ideal thermal radiator (blackbody) at the installation location. Within the meaning of this invention, emissivity is understood to represent the normal emissivity at 283K according to standard EN 12898.

[0040] The sheet resistance of the anti-radiation coating according to the invention is preferably from 10 ohms / square to 100 ohms / square, particularly preferably from 20 ohms / square to 60 ohms / square. The sheet resistance and inner emissivity of the panel according to the invention are related, wherein a decrease in the sheet resistance of the anti-radiation coating leads to a decrease in the inner emissivity.

[0041] The substrate is made of an electrically insulating, particularly rigid, material, preferably ceramic or glass. In a preferred embodiment, the substrate contains soda-lime glass, but in principle, other types of glass, such as borosilicate glass or quartz glass, may also be used. The substrate can be substantially transparent, or it can be colored or stained. The substrate is preferably 0.1 mm to 20 mm thick, typically 1.5 mm to 5 mm. The substrate can be designed to be flat or curved.

[0042] The refractive index specified within the scope of this invention can be determined, for example, by elliptic polarization spectroscopy, wherein a commercially available elliptic polarimeter, such as that manufactured by Sentech, can be used.

[0043] The panel comprising a substrate and a radiation-reducing coating according to the present invention is characterized by good absorption and optical properties. However, these properties can be further improved by heat treatment. Therefore, the panel according to the present invention can also be considered as an intermediate product in the production of heat-treated panels.

[0044] Therefore, the present invention also relates to a heat-treated panel obtained by heat-treating the panel according to the invention at at least 400°C. The heat treatment is preferably carried out at a temperature of at least 500°C, particularly preferably at a temperature of at least 600°C. The heat treatment is preferably carried out for at least 1 minute, particularly preferably at least 2 minutes, and very particularly preferably at least 5 minutes, for example, a period of 10 minutes.

[0045] Heat treatment can, in particular, reduce the sheet resistance of the anti-radiation coating. The anti-radiation coating of the heat-treated panel according to the invention preferably has a sheet resistance of 10 ohms / square to 100 ohms / square, particularly preferably 20 ohms / square to 60 ohms / square. The inner emissivity of the heat-treated panel according to the invention is preferably less than or equal to 45%, particularly preferably less than or equal to 35%, and very particularly preferably less than or equal to 30%, wherein the inner emissivity of the heat-treated panel according to the invention is measured in the same manner as that of the panel according to the invention.

[0046] Furthermore, the optical properties of the heat-treated panel according to the present invention are significantly improved compared to those of the panel according to the present invention; in particular, the visible light transmittance is increased. The heat treatment can be performed in various ways, such as by heating the panel in a furnace or by a radiant heater. Alternatively, the heat treatment can also be performed by light irradiation, such as using a lamp or laser as a light source.

[0047] In an advantageous embodiment, heat treatment is performed as part of a thermal tempering process or as part of a bending process, particularly when the substrate is made of glass. As part of the thermal tempering process, the heated substrate is exposed to an airflow, causing it to cool rapidly. Compressive stress is formed on the panel surface, and tensile stress is formed in the panel core. This characteristic stress distribution increases the breaking strength of the glass sheet. A bending process may also be performed prior to tempering.

[0048] Heat treatment causes the surface layer to oxidize with oxygen in the ambient air. For example, if the top layer is based on silicon (Si) and is undoped, the silicon absorbs oxygen from the ambient air and is at least partially oxidized to form silicon dioxide (SiO2) due to heat treatment. In the case of a doped top layer, such as silicon doped with aluminum (Si:Al), oxidation also occurs during heat treatment, resulting in the top layer containing Si after heat treatment. x Al y O z .

[0049] The substrate can be transparent or translucent, for example, colored. Within the meaning of this invention, "transparent" means (according to ISO 9050:2003) a light transmittance of at least 50%, preferably at least 60%, and particularly preferably at least 70%. Within the meaning of this invention, "translucent" (according to ISO 9050:2003) means a light transmittance of at most 50%, preferably at most 30%, and particularly preferably at most 10%.

[0050] Besides being used as a single-layer panel, the panel according to the invention or the heat-treated panel according to the invention can also be part of a laminated panel. Therefore, the invention also relates to a laminated panel. The laminated panel comprises a panel according to the invention or a heat-treated panel according to the invention, a thermoplastic interlayer, and a second panel. The second panel is connected to the panel or the heat-treated panel via the thermoplastic interlayer. A radiation-reducing coating is disposed on a first surface of the substrate opposite to the second panel.

[0051] The second panel preferably comprises or is substantially composed of a second substrate. Like the substrate, the second substrate is made of an electrically insulating, particularly rigid, material, preferably glass or plastic. In a preferred embodiment, the second substrate contains soda-lime glass, but in principle, other types of glass, such as borosilicate glass or quartz glass, may also be included. In another preferred embodiment, the second substrate contains polycarbonate (PC) or polymethyl methacrylate (PMMA). In a preferred embodiment, the second substrate is made of the same material as the first substrate. The second substrate can be substantially transparent, or it can be colored or dyed. The second substrate preferably has a thickness of 0.1 mm to 20 mm, typically 1.5 mm to 5 mm. The second substrate can be designed to be planar or curved.

[0052] In the automotive field, the laminated panel according to the invention can be particularly used as a roof panel. In this case, preferably, the panel or heat-treated panel forms the inner panel of the laminated panel, i.e., it faces the interior of the vehicle. In this case, the second panel forms the outer panel of the laminated panel and thus faces the external environment. A radiation-reducing coating is then applied to the inner-facing first surface of the substrate.

[0053] Alternatively, the panel, or a heat-treated panel, may form the outer panel of the laminated panel, i.e., facing the external environment. In this case, the second panel forms the inner panel of the laminated panel and therefore faces inward. The anti-radiation coating is then applied to the first surface of the substrate facing the external environment.

[0054] The thermoplastic interlayer is preferably formed as at least one thermoplastic laminate and is based on ethylene-vinyl acetate (EVA), polyvinyl butyral (PVB), or polyurethane (PU), or mixtures or copolymers thereof, or derivatives thereof, particularly preferably based on polyvinyl butyral (PVB), and additional additives known to those skilled in the art, such as plasticizers. The thermoplastic laminate preferably contains at least one plasticizer. The thermoplastic interlayer preferably has a thickness of 0.3 mm to 2 mm, with a standard thickness of 0.76 mm being particularly common. The thermoplastic interlayer may also comprise multiple layers of thermoplastic material and may be formed, for example, from multiple polymer films arranged flat on top of each other.

[0055] The above-described embodiments and preferred embodiments concerning the panel, heat-treated panel, and laminated panel are equally applicable to the method. The following embodiments and preferred embodiments of the method according to the invention are equally applicable to the panel, heat-treated panel, and laminated panel.

[0056] The present invention also relates to a method for producing a panel according to the invention or a heat-treated panel according to the invention, wherein at least: a) Provide base materials, b) In the specified order • Functional layer based on transparent conductive oxide • A first optically low-refractive layer with a refractive index less than or equal to 1.6, and • Silicon-based top layers with a thickness of 1nm to 20nm It is applied to the first surface of the substrate.

[0057] According to the present invention, the first optically low-refractive-index layer is applied directly onto the functional layer; no other layer is applied to the functional layer prior to the first optically low-refractive-index layer. The method for producing a panel according to the present invention has the advantage that no additional gas separation is required during the application of the functional layer and the first optically low-refractive-index layer. Therefore, the panel according to the present invention can be produced with minimal production input and low cost.

[0058] In a preferred embodiment, prior to step b), an optically high refractive index layer with a refractive index greater than or equal to 1.9 and / or a second optically low refractive index layer with a refractive index less than or equal to 1.6 are applied to the substrate in a specified order.

[0059] The layers of the radiation-reducing coating can be applied by methods known per se, preferably by vapor deposition, particularly preferably by physical vapor deposition, and very particularly preferably by magnetic field-assisted cathode sputtering (magnetron sputtering). This is particularly advantageous for simple, rapid, inexpensive, and uniform coating of the substrate. Cathode sputtering is performed in an inert gas atmosphere (e.g., argon) or in a reactive gas atmosphere (e.g., by adding oxygen or nitrogen). However, the layers can also be applied by other methods known to those skilled in the art, such as by evaporation deposition or chemical vapor deposition (CVD), by atomic layer deposition (ALD), by plasma-enhanced chemical vapor deposition (PECVD), or by wet chemical methods.

[0060] In a particularly preferred embodiment, the panel according to the invention is subsequently heat-treated to obtain the heat-treated panel according to the invention. For this purpose, the panel is heated to a temperature of at least 400°C. In a particularly advantageous embodiment, the panel is heated to at least 500°C, and particularly at least 600°C. Preferably, the heat treatment is performed as part of a heat tempering process or a bending process.

[0061] A panel according to the invention, a heat-treated panel according to the invention, or a laminated panel according to the invention can be a component of a light-emitting assembled glass element. The light-emitting assembled glass element comprises a panel according to the invention, a heat-treated panel according to the invention, or a laminated panel according to the invention, and further comprises at least one light source adapted to couple light into a substrate such that the light propagates within the substrate, particularly through total internal reflection at a first surface of the substrate, and at least one light-scattering structure adapted to couple light out of the substrate through a first surface and a second surface. A panel according to the invention, a heat-treated panel according to the invention, or a laminated panel according to the invention is particularly suitable as a component of a light-emitting assembled glass element because the anti-radiation coating does not cause a significant loss in the intensity of the coupled light.

[0062] The present invention also relates to the use of panels according to the invention, heat-treated panels according to the invention, or laminated panels according to the invention in buildings or land, air, or water vehicles, particularly in trains, ships, and motor vehicles, for example as windshields, rear panels, roof panels, and / or side panels, especially preferably as roof panels.

[0063] The invention will now be explained in more detail with the aid of the accompanying drawings and specific embodiments. The drawings are schematic and not drawn to scale. The drawings do not limit the invention in any way.

[0064] In the attached diagram: Figure 1 A cross-section of a panel according to an embodiment of the invention is shown. Figure 2A cross-section of a panel according to another embodiment of the invention is shown. Figure 3 A cross-section of one embodiment of the laminated panel according to the present invention is shown. Figure 4 A flowchart illustrating a method for producing a panel according to the invention is shown.

[0065] Figure 5 A flowchart illustrating a method for producing a heat-treated panel according to the present invention is shown.

[0066] Figure 1 An embodiment of a panel 10 according to the present invention is shown. The panel 10 comprises a substrate 1 and a radiation-reducing coating 2. The substrate 1 is made of, for example, soda-lime glass and has a thickness of 2.1 mm. The panel 10 is provided, for example, as the top plate of a motor vehicle. The substrate 1 has a first surface IV and a second surface III, wherein the radiation-reducing coating 2 is disposed on the first surface IV. Starting from the substrate 1, the radiation-reducing coating 2 comprises a functional layer 2.1, a first optically low refractive index layer 2.2, and a top layer 2.3. The functional layer 2.1 is formed based on a transparent conductive oxide, such as indium tin oxide (ITO), and has a thickness of, for example, 72 nm. The first optically low refractive index layer 2.2 is formed based, for example, aluminum-doped silicon oxide (SiO2:Al), and has a thickness of 50 nm. The top layer 2.3 is composed, for example, aluminum-doped silicon (Si:Al), and has a thickness of 5 nm.

[0067] Figure 2 Another embodiment of panel 10 according to the present invention is shown. Figure 2 The implementation scheme shown is the same as Figure 1 The illustrated embodiment differs only in that an optically high refractive index layer 2.4 and a second optically low refractive index layer 2.5 are disposed between the substrate 1 and the functional layer 2.1. The optically high refractive index layer 2.4 is disposed directly adjacent to the first surface IV of the substrate 1 and has a refractive index greater than or equal to 1.9. The optically high refractive index layer 2.4 is formed, for example, based on aluminum-doped silicon nitride (Si3N4:Al) and has a thickness of 30 nm.

[0068] The second optical low-refractive-index layer 2.5 has a refractive index less than or equal to 1.6 and is disposed between the optical high-refractive-index layer 2.4 and the functional layer 2.1. The second optical low-refractive-index layer 2.5 is formed, for example, based on aluminum-doped silicon oxide (SiO2:Al) and has a thickness of 20 nm.

[0069] Figure 3 An embodiment of a laminated panel according to the present invention is shown. The laminated panel comprises components from... Figure 1The laminated panel comprises a panel 10, a thermoplastic interlayer 11, and a second panel 12, the second panel 12 having a first surface I and a second surface II. The interlayer 11 is made of, for example, polyvinyl butyral (PVB) and has a thickness of 0.76 mm. The second panel 12 is designed as a second substrate made of glass, for example, soda-lime glass, and has a thickness of 2.1 mm. The laminated panel is, for example, the roof panel in a motor vehicle. The thermoplastic interlayer 11 is connected to the second surface III of the substrate 1 and the second surface II of the second panel 12. Typically, in this case, panel 10 is the inner panel facing the interior of the vehicle, and the second panel 12 is the outer panel of the laminated panel facing the external environment. In this case, the first surface IV of the substrate 1, on which an anti-radiation coating 2 is applied, faces the interior of the vehicle.

[0070] Figure 4 A flowchart illustrating a method for producing a panel 10 according to the present invention is shown. The first step, S1, is to provide a substrate 1.

[0071] As a second step S2, a radiation-reducing coating 2 is then applied to the first surface IV of the substrate 1. First, a functional layer 2.1 based on a transparent conductive oxide is applied. Subsequently, a first optically low-refractive-index layer 2.2 with a refractive index less than or equal to 1.6 is directly applied to the functional layer 2.1. Then, a top layer 2.3 with a thickness of 1 nm to 20 nm, which is based on silicon, is applied.

[0072] Figure 5 A flowchart illustrating a method for producing a heat-treated panel according to the present invention is shown. Figure 5 The method shown is the same as Figure 4 The only difference in the method shown is that, after the second step S2, as a third step S3, panel 10 is also heat-treated at at least 400°C.

[0073] The structure of the anti-radiation coating is explained below with reference to embodiments and comparative examples according to the present invention. The layer structures shown should be understood as examples only. Exemplary materials and layer thicknesses can be found in the following embodiments.

[0074] Table 1 .

[0075] Table 1 shows comparative examples V1, V2, and V3 of panels not according to the invention, and embodiments B1, B2, B3, B4, and B5 of panels according to the invention. In all comparative examples and all embodiments according to the invention, the corresponding panels comprise a substrate 1 made of soda-lime glass with a thickness of 2.1 mm. A radiation-reducing coating is applied to the substrate 1, the design of which differs between the embodiments and comparative examples according to the invention. In embodiments B1, B2, B3, B4, and B5 according to the invention, the radiation-reducing coating 2 comprises, starting from the substrate 1, an optically high refractive index layer 2.4, a second optically low refractive index layer 2.5, a functional layer 2.1, a first optically low refractive index layer 2.2, and a top layer 2.3. Embodiments B1, B2, and B3 according to the invention differ only in the thickness of the top layer 2.3, which is 2 nm thick in B1, 5 nm thick in B2, and 10 nm thick in B3. Embodiments B4 and B5 according to the invention have the same layer order as embodiments B1, B2, and B3, but their layer thicknesses differ. The difference between Comparative Example V1 and Embodiments B1, B2, and B3 according to the present invention is only that the top layer 2.3 is absent in Comparative Example V1; instead, an additional layer is disposed between the functional layer 2.1 and the first optical low-refractive-index layer 2.2, which is formed based on aluminum-doped silicon nitride (Si3N4:Al) and has a thickness of 9 nm. The difference between Comparative Example V2 and Embodiments B1, B2, and B3 according to the present invention is only that the top layer 2.3 is absent. The difference between Comparative Example V3 and Embodiments B4 and B5 according to the present invention is only that the top layer 2.3 is absent; instead, an additional layer is disposed between the functional layer 2.1 and the first optical low-refractive-index layer 2.2, which is formed based on aluminum-doped silicon nitride (Si3N4:Al) and has a thickness of 9 nm.

[0076] Table 2 .

[0077] Table 2 shows the visible light reflectance RL (%), visible light transmittance TL (%), and visible light absorptivity (%) of comparative examples V1, V2, V3, V1*, V2*, and V3*, and embodiments B1, B2, B3, B4, B5, B1*, B2*, B3*, B4*, and B5* according to the present invention. V1*, V2*, and V3* represent the state of the panels from comparative examples V1, V2, and V3 after heat treatment at 640°C for 10 minutes; similarly, B1*, B2*, B3*, B4*, and B5* represent the heat-treated panels according to the present invention, which are obtained by heat treatment at 640°C for 10 minutes on the panels according to embodiments B1, B2, B3, B4, and B5. Reflectivity RL represents the proportion of light incident on the panel that is reflected at an angle of 8° relative to the surface normal from the direction toward the first surface IV with the anti-radiation coating, while transmittance TL represents the proportion of visible light transmitted through the panel at an angle of 0° relative to the surface normal, and absorptivity describes the proportion of visible light absorbed by the anti-radiation coating. A type A light standard illuminator with a 10° detector was used. Reflectivity RL and transmittance TL were each measured using a TEC5 spectrometer. The specified values ​​for reflectivity RL, transmittance TL, and absorptivity were determined by averaging the visible light spectrum in the wavelength range of 380 nm to 780 nm.

[0078] As described above, the heat treatment at least partially causes the top layer to oxidize with oxygen in the ambient air, resulting in the heat-treated top layer containing Si in Examples B1*, B2*, B3*, B4*, and B5*. x Al y O z Table 2 shows that the optical properties of the heat-treated panel according to the present invention are improved compared with the optical properties of the panel according to the present invention in its state before heat treatment, which can be seen in particular from the lower sheet resistance, increased transmittance and lower absorptivity.

[0079] Embodiments B1, B2, B3, B4, and B5 according to the invention exhibit values ​​similar to those of comparative examples V1, V2, and V3 in terms of transmission, reflection, and absorption properties; similarly, embodiments B1*, B2*, B3*, B4*, and B5* of the heat-treated panel according to the invention exhibit values ​​similar to those in terms of transmission, reflection, and absorption properties.

[0080] The panels of embodiments B1, B2, B3, B4 and B5 according to the present invention, and the heat-treated panels of embodiments B1*, B2*, B3*, B4* and B5* according to the present invention, all have a transmittance greater than or equal to 77%, wherein the heat-treated panels of embodiments B1* to B5* according to the present invention even have a transmittance greater than or equal to 84%.

[0081] Embodiments B1* and B2* of the heat-treated panels according to the invention exhibit particularly low absorbance values ​​of 1.4% and 1.2%, respectively.

[0082] Embodiments B1, B2, B3, B4, and B5 of the panels according to the invention have a sheet resistance of less than 80 Ω / sq; embodiments B1*, B2*, and B3* of the heat-treated panels according to the invention have a sheet resistance of 30 Ω / sq to 40 Ω / sq. The reduced sheet resistance in the heat-treated state particularly demonstrates the improvement in radiation reduction performance caused by heat treatment, since the reduction in sheet resistance indicates a reduction in internal emissivity.

[0083] For the comparative examples and embodiments V1*, V3*, B1*, B2*, B3*, B4*, and B5* of the heat-treated panels, the inner emissivity is also specified. In all embodiments B1*, B2*, B3*, B4*, and B5* of the heat-treated panels according to the invention, the emissivity is less than 45%, and in embodiments B3* and B4*, it is even less than 30%.

[0084] List of reference numerals in the attached diagram: (10) Panel (1) Substrate (2) Anti-radiation coating (2.1) Functional Layer (2.2) First optical low-refractive layer (2.3) Top layer (2.4) Optical high-refractive layer (2.5) Second optical low-refractive layer (11) Intermediate layer (12) Second panel (I) First surface of the second panel 12 (II) Second surface of second panel 12 (III) Second surface of substrate 1 (IV) First surface of substrate 1

Claims

1. A panel (10) comprising a substrate (1) and a radiation-reducing coating (2) on a first surface (IV) of the substrate (1), the coating comprising at least the following components in a specified order starting from the substrate (1): • Based on the functional layer of transparent conductive oxide (2.1), • A first low-refractive-index layer (2.2) with a refractive index less than or equal to 1.

6. • A top layer with a thickness of 1nm to 20nm (2.3), The top layer (2.3) is formed based on silicon, and The first optical low-refractive layer (2.2) is arranged directly adjacent to the functional layer (2.1).

2. The panel (10) according to claim 1, wherein the functional layer (2.1) is formed based on indium tin oxide.

3. The panel (10) according to claim 1 or 2, wherein the thickness of the functional layer (2.1) is 30 nm to 200 nm, preferably 50 nm to 130 nm.

4. The panel (10) according to any one of claims 1 to 3, wherein the first optical low refractive layer (2.2) has a thickness of 30 nm to 200 nm and / or is formed based on doped or undoped silicon oxide.

5. The panel (10) according to any one of claims 1 to 4, wherein the thickness of the top layer (2.3) is 2 nm to 15 nm, preferably 3 nm to 14 nm.

6. The panel (10) according to any one of claims 1 to 5, wherein the top layer (2.3) is composed of doped or undoped silicon, preferably of zirconium-doped silicon, titanium-doped silicon, hafnium-doped silicon or aluminum-doped silicon, and very particularly preferably of aluminum-doped silicon.

7. The panel (10) according to any one of claims 1 to 6, wherein the first optical low refractive layer (2.2) is arranged directly adjacent to the top layer (2.3).

8. The panel (10) according to any one of claims 1 to 7, wherein the anti-radiation coating (2) further comprises, starting from the substrate (1), in a specified order: • Optical high-refractive-index layer (2.4) with a refractive index greater than or equal to 1.9 and / or • A second low-refractive-index layer (2.5) with a refractive index less than or equal to 1.

6. The optical high refractive layer (2.4) and the second optical low refractive layer (2.5) are located at a smaller distance from the substrate (1) than the functional layer (2.1).

9. The panel (10) according to claim 8, wherein the optical high-refractive-index layer (2.4) is formed based on silicon nitride, aluminum-doped silicon nitride, titanium-doped silicon nitride, zirconium-doped silicon nitride, or boron-doped silicon nitride. And / or the second optical low-refractive layer (2.5) is formed based on silicon oxide, aluminum-doped silicon oxide, titanium-doped silicon oxide, zirconium-doped silicon oxide or boron-doped silicon oxide.

10. A heat-treated panel obtained by heat-treating a panel (10) according to any one of claims 1 to 9 at at least 400°C.

11. A laminated panel comprising a panel (10) according to any one of claims 1 to 9 or a heat-treated panel according to claim 10, a thermoplastic interlayer (11), and a second panel (12), The second panel (12) is connected to the panel (10) or the heat-treated panel via a thermoplastic interlayer (11), and the anti-radiation coating (2) is disposed on a first surface (IV) of the substrate (1) opposite to the second panel (12).

12. A method for producing a coated panel (10) according to any one of claims 1 to 9 or a heat-treated panel according to claim 10, wherein at least: a) Provide substrate (1), b) In the specified order • Based on the functional layer of transparent conductive oxide (2.1), • A first low-refractive-index layer (2.2) with a refractive index less than or equal to 1.

6. • Silicon-based top layers with a thickness of 1nm to 20nm (2.3) The first optical low refractive layer (2.2) is applied to the first surface (IV) of the substrate (1), wherein the first optical low refractive layer (2.2) is applied directly to the functional layer (2.1).

13. The method according to claim 12, wherein prior to step b), an optical high-refractive-index layer (2.4) with a refractive index greater than or equal to 1.9 and / or a second optical low-refractive-index layer (2.5) with a refractive index less than or equal to 1.6 are applied to the first surface (IV) of the substrate (1) in a specified order.

14. The method for producing a heat-treated panel according to claim 10 according to claim 12 or 13, wherein after step b), the panel (10) is heated to at least 400°C, preferably at least 500°C, particularly preferably at least 600°C.

15. Use of the panel (10) according to any one of claims 1 to 9, the heat-treated panel according to claim 10, or the laminated panel according to claim 11 in buildings or land, air, or water vehicles, particularly in trains, ships, and motor vehicles, for example as windshields, rear panels, side panels, and / or roof panels.

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