Composite glass pane with an electrically conductive coating and at least one layer comprising selectively absorbing nanoparticles

Abstract

Composite glass pane (10) with an electrically conductive coating (20), comprising at least an outer glass pane (1) with an outer side surface (I) and an inner side surface (II) and an inner glass pane (2) with an outer side surface (III) and an inner side surface (IV), wherein the inner side surface (II) of the outer glass pane (1) and the outer side surface (III) of the inner glass pane (2) are joined to one another by a thermoplastic intermediate layer (3), and wherein between the inner side surface (II) of the outer glass pane (1) and the outer side surface (III) of the inner glass pane (2) at least - the electrically conductive coating (20) and - at least one layer of selectively absorbing nanoparticles (30) with an absorption in the wavelength range of 580 nm to 750 nm are arranged.

Description

[0001] The present invention relates to a composite glass plate having a conductive coating and at least one layer comprising selectively absorbing nanoparticles.

[0002] Composite glass panels with conductive coatings are well-known in the vehicle industry, for example, as windshield panels with a heatable transparent coating. This coating typically comprises multiple silver layers applied alternately with dielectric layers, thereby ensuring both high conductivity and sufficient transmittance in the visible spectrum. More complex conductive coatings for windshield panels are also known, for example, as IR-reflective coatings to reduce temperature rise in the vehicle's interior and thus improve thermal comfort. However, the coating can also be used as a heatable coating, achieved by connecting it to a voltage source to allow current to flow through it. Suitable coatings contain conductive metallic layers, particularly silver-based. Because these layers are susceptible to corrosion, they are typically applied to the surface of the outer or inner glass panel facing the interlayer to prevent them from contacting the atmosphere. Silver-containing transparent coatings are known, for example, from WO03 / 024155, US2007 / 0082219A1, US2007 / 0020465A1, WO2013 / 104438 or WO2013 / 104439.

[0003] In addition, so-called low-emissivity coatings are also known, which, for example, contain a functional layer made of ITO, as described in WO2013 / 131667. Compared to silver-based coatings, such coatings are less sensitive to corrosion and can therefore be used on the outer surface of composite glass panels, particularly on the inner surface of the inner glass panel.

[0004] US 2015 / 0202846 A1 discloses a PVB film with a low plasticizer ratio and a conductive or reflective coating.

[0005] US 2010 / 0220388 A1 describes a laminate comprising a layer that absorbs radiation in the wavelength range of 200 nm to 500 nm.

[0006] Especially in the automotive sector, there is a strong demand for sun-protective coatings that are not only heatable but also have low Total Solar Transmittance (TTS), low lateral reflectivity, and neutral or blue or green reflective colors. In particular, yellow, red, and purple reflective colors are considered disruptive and should be avoided. Good sun protection for vehicle mounting glass also helps reduce the energy consumption of air conditioning systems, making it environmentally desirable. In electric vehicles, reducing the energy consumption of secondary systems such as air conditioning and heating systems translates to increased driving range. Low Total Solar Transmittance (TTS) is generally associated with high lateral reflectivity of the coating, but in practice, the lowest possible values ​​for both are desirable. Furthermore, windshield panels must comply with the legal requirements for testing the transmittance of motor vehicle glass panels according to ECE-R 43, Annex 3, Section 9.1, whereby the TTS must be at least 70%. This makes achieving low TTS even more challenging. These requirements for low TTS, heatability of the coating, and sufficient transmittance often result in non-compliance with standards for visually appealing reflective colors of the coating. In addition to the slightly reddish reflective color of the coating, which is almost unacceptable to end customers, the reflected color of images on the composite glass panel is also affected. For example, when the composite glass panel is used as a head-up display, a reddish phantom appears.

[0007] Therefore, there is a need for composite glass panels with a conductive coating having a neutral color, particularly a neutral outer reflective color. The object of this invention is to provide such an improved composite glass panel.

[0008] According to the present invention, the objective of the invention is achieved by the composite glass plate according to the invention. Preferred embodiments will be derived from further description.

[0009] The composite glass plate according to the invention comprises an outer glass plate having an outer surface (side I) and an inner surface (side II), an inner glass plate having an outer surface (side III) and an inner surface (side IV), and a thermoplastic interlayer bonding the inner surface of the outer glass plate to the outer surface of the inner glass plate, wherein the composite glass plate has at least one conductive coating and at least one selectively absorbing nanoparticle layer between the outer and inner glass plates. The conductive coating and the selectively absorbing nanoparticle layer are stacked face-to-face, wherein the layer order of the two elements can be varied, and they can be arranged directly or indirectly adjacent to each other. In this sense, face-to-face stacking means that the projection of the selectively absorbing nanoparticle layer onto the plane of the conductive coating is at least partially superimposed on the conductive coating. The selectively absorbing nanoparticle layer has absorption in the wavelength range of 580 nm to 750 nm. The selectively absorbing nanoparticle layer absorbs electromagnetic radiation of one or more wavelengths within this wavelength range, which corresponds to the yellow or red range of the visible spectrum. Light reflected by the conductive coating and then reflected through the selectively reflecting nanoparticle layer is filtered in terms of its color. The selectively absorbing nanoparticle layer exhibits selective absorption in the wavelength range of 580 nm to 750 nm, while absorption in the remaining wavelength range of visible light occurs only to a minor degree. After passing through the selectively absorbing nanoparticle layer, the intensity of light in the yellow or red range is significantly reduced. Due to absorption in the red range of the visible spectrum, the overall color of the composite glass plate shifts towards a bluish-green hue. This can thus compensate for the slight reddish reflection caused by the conductive coating, resulting in a more neutral color impression. End customers and vehicle manufacturers find a slightly bluish or greenish reflection pleasing and acceptable, in contrast to a reddish hue. Therefore, this invention enables the selective application of the conductive coating, particularly in terms of its electrical properties and total solar transmittance, where the coating's reflective color plays a minor or no role.

[0010] Composite glass panels are used to separate interior space from the external environment in window openings, particularly in vehicle window openings. In the context of this invention, the inner glass panel refers to the glass panel of the composite glass panel facing the interior space (particularly the interior space of the vehicle). The outer glass panel refers to the glass panel facing the external environment. The composite glass panel is preferably a vehicle windshield (particularly a windshield of a motor vehicle, such as a passenger vehicle or a truck), or preferably a vehicle roof glass panel. The outer and inner glass panels each have an outer surface and an inner surface, and a surrounding side edge extending between them. In the context of this invention, the outer surface refers to the main surface provided for facing the external environment in the installation position. In the context of this invention, the inner surface refers to the main surface provided for facing the interior space in the installation position. The inner surface of the outer glass panel and the outer surface of the inner glass panel face each other and are bonded together by a thermoplastic interlayer.

[0011] The intermediate layer of the composite glass sheet is formed of at least one thermoplastic material sublayer. The intermediate layer may consist of this single thermoplastic material sublayer and is formed, for example, from a single polymer film or a cast resin layer. However, the intermediate layer may also include multiple thermoplastic material sublayers and is formed, for example, from multiple polymer films stacked on top of each other. Particularly preferably, the intermediate layer comprises one or more thermoplastic composite films. Multiple thermoplastic composite films are particularly useful if the thermoplastic intermediate layer includes a carrier film embedded between the thermoplastic composite films.

[0012] The composite glass panel also has at least one layer of selectively absorbing nanoparticles. This layer can be disposed on the outer side and / or the inner side of the conductive coating. Disposing it on the outer side is preferred because this advantageously affects the reflected color visible from the outside when viewed from around the vehicle. Disposing it on the outer side means the selectively absorbing nanoparticle layer is located between the outer surface of the outer glass panel and the conductive coating. In the case of being disposed on the inner side, the selectively absorbing nanoparticle layer is located between the inner surface of the inner glass panel and the conductive coating. When viewed through the composite glass panel, the at least one selectively absorbing nanoparticle layer preferably overlaps with the entire conductive coating.

[0013] The at least one selectively absorbing nanoparticle layer is preferably formed from a thermoplastic film of an intermediate layer, in which the selectively absorbing nanoparticles are embedded. Alternatively, the selectively absorbing nanoparticle layer can be applied to another layer of the layer stack. The thermoplastic intermediate layer is particularly preferably formed from at least one thermoplastic film, and the selectively absorbing nanoparticles are embedded in the at least one thermoplastic film to form the selectively absorbing nanoparticle layer from the thermoplastic film, wherein at least 0.1% by weight, preferably at least 1% by weight, of the selectively absorbing nanoparticles is embedded in the at least one thermoplastic film. For example, from 1% to 5% by weight of the selectively absorbing nanoparticles can be embedded in at least one thermoplastic film.

[0014] Therefore, different localizations of the at least one selectively absorbing nanoparticle layer are possible:

[0015] - On the surface of one of the glass plates, particularly on the inner surface of the outer glass plate and / or the outer surface of the inner glass plate,

[0016] - On a carrier film embedded in the intermediate layer. This carrier film can be, for example, formed of polyethylene terephthalate (PET) with a thickness of about 50 μm and disposed between two thermoplastic sublayers.

[0017] - Embedded in the thermoplastic composite film of the intermediate layer.

[0018] The conductive coating is preferably disposed on the inner surface of the outer glass plate or the outer surface of the inner glass plate. Alternatively, the conductive coating may be disposed on a carrier film embedded between the two thermoplastic composite films of the intermediate layer. The carrier film may, for example, be formed of polyethylene terephthalate (PET) with a thickness of about 50 μm.

[0019] In a preferred embodiment, the at least one selectively absorbing nanoparticle layer is disposed on the outer side of the conductive coating. Therefore, the distance between the at least one selectively absorbing nanoparticle layer and the outer glass plate is less than the distance between the conductive coating and the outer glass plate. Ambient light incident on the composite glass plate thus falls onto the outer glass plate of the composite glass plate, passes through the at least one selectively absorbing nanoparticle layer, and is partially reflected on the conductive coating. The reflected light portion then passes through the at least one selectively absorbing nanoparticle layer again, exits on the outer glass plate of the composite glass plate, and is perceived as reflected color there. When light passes through the selectively absorbing nanoparticle layer, portions of the light in the yellow or red range of the spectrum are removed due to absorption, resulting in a neutral to slightly greenish or slightly blue reflected color on the outer side.

[0020] In another preferred embodiment, at least one selectively absorbing nanoparticle layer is disposed inside the conductive coating. Here, the distance between the at least one selectively absorbing nanoparticle layer and the inner glass plate is less than the distance between the conductive coating and the inner glass plate. Light incident on the composite glass plate from the interior space of the vehicle thus falls onto the inner glass plate of the composite glass plate, passes through the at least one selectively absorbing nanoparticle layer, and is partially reflected on the conductive coating. The reflected light portion then passes through the at least one selectively absorbing nanoparticle layer again, exits on the inner glass plate of the composite glass plate, and is perceived as reflected color there. In this case, the inner reflected color is also shifted towards a neutral or slightly blue or slightly greenish color impression by the absorption of the yellow or red portion of light by the selectively absorbing nanoparticle layer.

[0021] In another preferred embodiment, the composite glass plate has at least two layers of selectively absorbing nanoparticles, wherein a conductive coating is disposed between these layers. In this way, both the reflected color visible on the outer side and the reflected color visible on the inner side of the composite glass plate can be shifted towards an attractive hue.

[0022] The conductive coating and the at least one selectively absorbing nanoparticle layer can be applied to the inner surface (II) of the outer glass plate, the outer surface (III) of the inner glass plate, and / or embedded in the carrier film of the thermoplastic interlayer. The selectively absorbing nanoparticle layer can also be directly disposed in the thermoplastic interlayer, which is achieved by giving the thermoplastic composite film of the thermoplastic interlayer selectively absorbing nanoparticles.

[0023] The at least one selectively absorbing nanoparticle layer is particularly preferably disposed outside the conductive coating, wherein the conductive coating is disposed on the outer surface (III) of the inner glass plate, and the at least one selectively absorbing nanoparticle layer is disposed within the interlayer. The selectively absorbing nanoparticle layer may here be disposed on a carrier film embedded in the interlayer. However, in particular, the nanoparticles are introduced directly into the material of the thermoplastic composite film of the interlayer. The conductive coating on the glass substrate can be implemented cost-effectively and with excellent quality using industrially available methods, such as magnetron sputtering. If the selectively reflective nanoparticle layer is directly integrated into the material of the thermoplastic interlayer, existing production processes can continue without alteration, wherein only another interlayer is provided. Furthermore, the attractive outer reflective color achieved in this embodiment is a decisive criterion for vehicle manufacturers and end customers.

[0024] In another particularly preferred embodiment, the at least one selectively absorbing nanoparticle layer is disposed inside the conductive coating, which is disposed on the inner surface (II) of the outer glass plate, and the at least one selectively absorbing nanoparticle layer is disposed within the intermediate layer. This selectively absorbing nanoparticle layer can be disposed on a carrier film embedded in the intermediate layer, but in particular, the nanoparticles are also introduced directly into the material of the thermoplastic composite film of the intermediate layer in this case. This embodiment is preferred if the color of the inner reflection visible within the vehicle's interior space should be improved, especially in reflective display applications such as head-up displays.

[0025] In another possible embodiment, the composite glass plate has a conductive coating between at least two selectively absorbing nanoparticle layers, wherein the conductive coating is applied to a carrier film embedded in a thermoplastic interlayer. The at least two selectively absorbing nanoparticle layers are respectively arranged on the inner surface (II) of the outer glass plate and the outer surface of the inner glass plate (III). Particularly preferably, one or both selectively absorbing nanoparticle layers are integrated directly through the thermoplastic composite film surrounding the carrier film, which is achieved by incorporating the nanoparticles into the material of the interlayer. Such an embodiment is advantageous if it is desired to adjust the reflective color on both sides. Alternatively, one or both selectively absorbing nanoparticle layers can also be introduced into the stacked body through the carrier film in the same way.

[0026] The thermoplastic interlayer is formed of at least one thermoplastic composite film. If a carrier film is integrated into the laminate of the composite glass sheet, the interlayer comprises at least two thermoplastic composite films with the carrier film embedded between them. The thermoplastic composite film can also be assembled from multiple individual composite films. The thermoplastic interlayer contains at least one thermoplastic polymer, preferably ethylene vinyl acetate (EVA), polyvinyl butyral (PVB), or polyurethane (PU), or mixtures, copolymers, or derivatives thereof, with PVB being particularly preferred. The thickness of the interlayer is preferably from 0.2 mm to 2 mm, particularly preferably from 0.3 mm to 1 mm. If a wedge-shaped interlayer is used, the thickness is measured at its thinnest point, typically at the lower edge of the composite glass sheet.

[0027] The selectively absorbing nanoparticle layer is preferably disposed directly within the thermoplastic interlayer itself. For this purpose, the selectively absorbing nanoparticles are embedded in at least one thermoplastic composite film to form the selectively absorbing nanoparticle layer from the thermoplastic film. This has the advantage that, on the one hand, no additional carrier film is required, and on the other hand, no additional step of applying the nanoparticles to the glass surface is needed. The thermoplastic composite film containing the selectively absorbing nanoparticle layer can be embedded in the laminate of the composite glass panel without altering the manufacturing process. The fabrication of the composite film containing the selectively absorbing nanoparticle layer is performed in advance and does not affect the manufacturing process of the composite glass panel.

[0028] The selective absorption nanoparticle layer preferably comprises nanoparticles based on semiconductor materials, particularly silicon (Si), zinc selenide (ZnSe), and / or cadmium telluride (CeTe), and / or perovskite-based nanoparticles. The inventors have found that these materials result in sufficient selective absorption. In particular, perovskites have proven especially suitable in this regard. Nanoparticles based on halogen-containing cesium lead perovskites, such as CsPbI3 or CsPb(I / Br)3, are particularly suitable. The term "perovskite" describes compounds with the general structure ABX3, where A and B are cations, A has a larger diameter than B, and X is an oxide anion (O... 2- ) or halide anion (F - ,Br - I - In addition, there are perovskites with a mixed cation structure of type (AA')(BB')O6, in which A and A' cations and B and B' cations are located at lattice positions A and B, respectively.

[0029] The selectively absorbing nanoparticle layer preferably has absorption in the wavelength range of 580 nm to 700 nm, and particularly preferably in the wavelength range of 590 nm to 690 nm. This can particularly effectively avoid the reddish hue of the reflected color.

[0030] The selective absorption nanoparticle layer preferably has at least 20%, more preferably at least 30%, and particularly preferably at least 40% absorption in the selective absorption wavelength range.

[0031] The conductive coating is preferably applied to either the inner or outer glass plate, i.e., the outer surface of the inner glass plate facing the interlayer or the inner surface of the outer glass plate facing the interlayer. Alternatively, the coating can be disposed within the interlayer. For this purpose, the coating is typically applied to a carrier film, for example, made of polyethylene terephthalate (PET) with a thickness of about 50 μm, disposed between two thermoplastic sublayers, such as between two polymer films. Preferably, at least 80% of the glass plate surface is equipped with the coating according to the invention. In particular, the composite glass plate is coated over its entire surface, except for optional local areas surrounding the edges and areas that, as communication, sensor, or camera windows, should ensure the transmission of electromagnetic radiation through the composite glass plate and are therefore uncoated. For example, the width of the uncoated surrounding edge area is at most 20 cm. This prevents direct contact between the coating and the surrounding atmosphere, thereby protecting the coating inside the composite glass plate from corrosion and damage.

[0032] Conductive coatings, particularly transparent conductive coatings, are used. Conductive coatings can be, for example, configured as IR-reflective sun-protective coatings, or as heat-resistant coatings that are electrically contacted and heated when an electric current flows through them. In a particularly preferred embodiment, the composite glass panel is a windshield panel of a motor vehicle, wherein the conductive coating is transparent. A transparent coating is understood to mean a coating having an average transmittance of at least 70%, preferably at least 75%, in the visible spectrum, i.e., it does not significantly restrict visibility through the glass panel. If the composite glass panel is used, for example, as a roof mount glass of a motor vehicle, the transmittance of the coating can be correspondingly lower.

[0033] The conductive coating includes at least one conductive layer. The conductive layer may contain metal, particularly silver, as is common for IR-reflective sunscreen coatings and heat-resistant coatings.

[0034] The conductive coating is preferably a stack of layers or a sequence of layers, comprising one or more conductive, particularly metallic, layers, wherein each conductive layer is disposed between two dielectric layers or a sequence of layers. For example, the coating is having n A conductive layer and ( n+1 A thin stack of dielectric layers or layer sequences, wherein nIt is a natural number and wherein conductive layers and dielectric layers or layer sequences alternately exist on the underlying dielectric layer or layer sequence, respectively. Such coatings are known as sun-protective coatings and heat-resistant coatings, wherein the conductive layers are typically formed based on silver. The conductive coating preferably comprises at least two conductive layers, particularly preferably at least three conductive layers, and very particularly preferably at least four conductive layers. The more conductive layers there are, the better the coating can be optimized in terms of desired transmittance, color, or sheet resistivity.

[0035] The conductivity of the coating is achieved through the functional conductive layer. By distributing the entire conductive material across multiple layers that are separated from each other, they can be made thinner, thereby increasing the transparency of the coating. Each conductive layer preferably contains at least one metal or metal alloy, such as silver, aluminum, copper, or gold, and is particularly preferably formed based on a metal or metal alloy, i.e., consisting essentially of a metal or metal alloy except for possible dopants or impurities. Silver or silver-containing alloys are preferably used. In an advantageous embodiment, the conductive layer contains at least 90% by weight of silver, preferably at least 99% by weight of silver, and particularly preferably at least 99.9% by weight of silver.

[0036] In a particularly preferred embodiment, the conductive coating comprises at least three conductive layers, which are particularly based on silver. This coating typically produces a red reflective color, and thus the invention particularly benefits from it.

[0037] According to the present invention, dielectric layers or layer sequences are arranged between conductive layers and below the bottom conductive layer and above the top conductive layer. Each dielectric layer or layer sequence has at least one anti-reflective layer. The anti-reflective layer reduces the reflection of visible light, thereby increasing the transparency of the coated glass plate. The anti-reflective layer comprises, for example, silicon nitride (SiN), silicon-metal mixed nitrides such as zirconium silicon nitride (SiZrN), aluminum nitride (AlN), or tin oxide (SnO2). The anti-reflective layer may also have dopants.

[0038] The antireflective layer can be further divided into at least two sub-layers, specifically a dielectric layer with a refractive index less than 2.1 and an optically high refractive index layer with a refractive index greater than or equal to 2.1. Preferably, at least one antireflective layer is disposed between two conductive layers in this manner, and particularly preferably, each antireflective layer is disposed between two conductive layers. This division of the antireflective layer results in a low sheet resistivity of the conductive coating while simultaneously exhibiting high transmittance and high color neutrality. The order of the two sub-layers can be chosen arbitrarily in principle, but the optically high refractive index layer is preferably disposed above the dielectric layer, which is particularly advantageous in terms of sheet resistivity. The thickness of the optically high refractive index layer is preferably 10% to 99% of the total thickness of the antireflective layer, particularly preferably 25% to 75%.

[0039] Optically high refractive index layers with a refractive index greater than or equal to 2.1 may include, for example, silicon-metal mixed nitrides, such as silicon-zirconium mixed nitrides (SiZrN). This is particularly advantageous in terms of the sheet resistance of the conductive coating. The silicon-zirconium mixed nitrides preferably have dopants. The optically high refractive index material layer may, for example, include aluminum-doped silicon-zirconium mixed nitrides.

[0040] The dielectric layer with a refractive index less than 2.1 preferably has a refractive index n of 1.6 to 2.1, and particularly preferably 1.9 to 2.1. The dielectric layer preferably contains at least one oxide and / or nitride, and particularly preferably silicon nitride.

[0041] In one advantageous embodiment, one or more dielectric layer sequences, preferably each dielectric layer sequence disposed below the conductive layer, have a first adapter layer. The first adapter layer is preferably disposed above the antireflective layer.

[0042] In an advantageous embodiment, one or more dielectric layer sequences, preferably each dielectric layer sequence disposed between two conductive layers, have a smoothing layer. The smoothing layer is disposed below one of the first adapter layers, preferably between the antireflective layer and the first adapter layer. The smoothing layer is particularly preferably in direct contact with the first adapter layer. The smoothing layer provides surface optimization, particularly smoothness, for the conductive layer subsequently applied above. Conductive layers deposited on smoother surfaces have higher transmittance and lower sheet resistance. The smoothing layer preferably has a refractive index of less than 2.2.

[0043] The smoothing layer preferably comprises at least one amorphous oxide. The oxide can be amorphous or partially amorphous (and therefore partially crystalline), but not fully crystalline. The amorphous smoothing layer has low roughness and thus forms a favorable smooth surface for the layer applied over it. The amorphous smoothing layer also provides an improved surface structure for the layer deposited directly over it, which is preferably the first adapting layer. For example, the smoothing layer can comprise at least one oxide of one or more of the elements tin, silicon, titanium, zirconium, hafnium, zinc, gallium, and indium. The smoothing layer particularly preferably comprises an amorphous mixed oxide. The smoothing layer very particularly preferably comprises a tin-zinc mixed oxide (ZnSnO). The mixed oxide can have dopants. The smoothing layer can comprise, for example, an antimony-doped tin-zinc mixed oxide. The mixed oxide preferably has a substoichiometric oxygen content.

[0044] In an advantageous embodiment, one or more dielectric layer sequences, preferably each dielectric layer sequence disposed above the conductive layer, have a second adapter layer. The second adapter layer is preferably disposed below the antireflective layer.

[0045] The first and second adapter layers improve the sheet resistivity of the coating. The first and / or second adapter layers preferably contain zinc oxide (ZnO) with a resistivity of 0 ≤ δ ≤ 0.01. 1-δThe first adapter layer and / or the second adapter layer also preferably contain dopants. For example, the first adapter layer and / or the second adapter layer may contain, for instance, aluminum-doped zinc oxide (ZnO:Al). The zinc oxide is preferably deposited in a substoichiometric manner with respect to oxygen to avoid excess oxygen reacting with the silver-containing layer.

[0046] In an advantageous embodiment, the conductive coating includes one or more barrier layers. Preferably, there is at least one, and particularly preferably, at least one barrier layer is provided for each conductive layer. The barrier layer is in direct contact with the conductive layer and is disposed directly above or directly below the conductive layer. Therefore, no other layer is disposed between the conductive layer and the barrier layer. The barrier layers may also be disposed directly above and directly below the conductive layer, respectively. The barrier layer preferably comprises niobium, titanium, nickel, chromium, and / or alloys thereof, particularly nickel-chromium alloys. The barrier layer located directly below the conductive layer is particularly useful for stabilizing the conductive layer during temperature processing and improving the optical quality of the conductive coating. The barrier layer located directly above the conductive layer prevents the sensitive conductive layer from coming into contact with an oxidizing reactive atmosphere during the deposition of subsequent layers, such as a second adapter layer, by reactive sputtering.

[0047] If the first layer is disposed above the second layer, this means, in the sense of the invention, that the first layer is disposed further away from the coated substrate than the second layer. If the first layer is disposed below the second layer, this means, in the sense of the invention, that the second layer is disposed further away from the substrate than the first layer. If the first layer is disposed above or below the second layer, this does not necessarily mean, in the sense of the invention, that the first and second layers are in direct contact with each other. Unless explicitly excluded, one or more other layers may be disposed between the first and second layers. The refractive index values ​​shown were measured at a wavelength of 550 nm. If a layer is based on a material forming layer, then the layer is primarily composed of that material, except for possible impurities or dopants.

[0048] If the conductive coating is configured as a heating coating, it is electrically connected to an external voltage source in a manner known per se, wherein the coating is heated by applying voltage. Electrical contact is achieved via suitable connecting cables, such as film conductors, which are preferably connected to the conductive coating via so-called busbars, such as strips of conductive material or conductive printing.

[0049] Preferably, at least two buses are attached to and electrically connected to the conductive coating. The at least two buses are preferably attached along opposite edges of the composite glass panel and can be electrically connected to the opposite pole of a voltage source for heating the glass panel. The coating area between the buses is electrically heated. In one possible embodiment of the invention, three buses are applied, each extending parallel to a horizontal edge of the glass panel in the state where the composite glass panel is mounted as a motor vehicle windshield, and a third bus projecting from the top edge toward the center of the glass panel. The first bus is located near the top edge, while the second bus is located near the engine edge, and these two buses extend parallel to these horizontal side edges. In a particularly preferred embodiment, one or more buses are adapted in shape to a possible uncoated area of ​​a sensor window for attaching a sensor. The thickness of the buses is 5 μm to 20 μm, preferably 8 μm to 15 μm. The width of the buses is 0.5 mm to 30 mm, preferably 1 mm to 20 mm.

[0050] An opaque overlay, such as a screen-printed material, is preferably applied to the edge regions of the composite glass panel, such that the screen-printed material surrounds the view of the glass panel or forms its outer edge. Busbars and electrical conductors that may be arranged in the edge regions of the composite glass panel, as well as optionally uncoated edge regions, are preferably covered by the overlay and thus visually hidden. The opaque screen-printed material is applied, for example, to the outer surface (III side) of the inner glass panel and / or the inner surface (II side) of the outer glass panel. Preferably, along the circumferential edge of the composite glass panel, along the circumferential strip, there is preferably no conductive coating. This uncoated area is hidden by the opaque overlay. Thus, the composite glass panel has a visually appealing appearance.

[0051] In one possible implementation, a composite glass panel serves as a windshield that includes a projection surface for a head-up display (HUD). Here, a HUD projector is positioned within the vehicle's interior space, projecting an image onto the composite glass panel from the inner surface of the inner glass panel. The HUD projector primarily operates using s-polarized radiation and illuminates the windshield at an angle of incidence of approximately 65%, close to the Brewster angle of the air-glass transition. The problem here is that the projected image is reflected on both outer surfaces of the windshield. Another reflection occurs at the conductive coating. Consequently, a slightly offset secondary image, known as a phantom, appears in addition to the desired primary image. This problem is typically mitigated by aligning the glass panel surfaces at an angle to each other, particularly by using a wedge-shaped interlayer to laminate the windshield designed as a composite glass panel, thereby allowing the primary image and the phantom to overlap. Composite glass with a wedge-shaped film for use in HUDs is known, for example, from WO2009 / 071135A1, EP1800855B1 or EP1880243A2. In a preferred embodiment of the composite glass panel, the intermediate layer comprises at least one wedge-shaped thermoplastic composite film.

[0052] The outer and inner glass panes are preferably made of glass, especially soda-lime glass, which is common for window panes. However, in principle, the glass panes can also be made of other types of glass (e.g., borosilicate glass, quartz glass, aluminosilicate glass) or transparent plastics (e.g., polymethyl methacrylate or polycarbonate). The thickness of the outer and inner glass panes can vary widely. Glass panes with a thickness of 0.7 mm to 5 mm are preferred, more preferably 1.4 mm to 2.5 mm, for example, glass panes with a standard thickness of 1.6 mm or 2.1 mm.

[0053] The outer glass pane, inner glass pane, and thermoplastic interlayer can be clear and colorless, but can also be colored or tinted. In a preferred embodiment, the total transmittance through the composite glass is greater than 70%. The term total transmittance is based on the method for testing the light transmittance of automotive glass panes as specified in 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 to be prestressed, this can be thermally prestressed or chemically prestressed.

[0054] Composite glass panels are preferably curved in one or more spatial directions, as is common for automotive glass panels, where the typical radius of curvature is from about 10 cm to about 40 m. However, composite glass panels can also be flat, for example when they are installed as glass panels for buses, trains, or tractors.

[0055] Composite glass sheets can be manufactured using methods known per se. The outer and inner glass sheets are laminated together via an interlayer, for example by autoclave method, vacuum bag method, vacuum ring method, calendering method, vacuum laminator, or a combination thereof. Here, the outer and inner glass sheets are typically joined under the influence of heat, vacuum, and / or pressure.

[0056] The selectively absorbing nanoparticle layer can be applied, for example, in the form of a solution containing the selectively absorbing nanoparticles to a glass plate surface, a carrier film, or a thermoplastic composite film to form the selectively absorbing nanoparticle layer. Preferably, the selectively absorbing nanoparticles are directly introduced into the thermoplastic starting material during the extrusion process of the thermoplastic composite film, thereby directly configuring the selectively absorbing nanoparticle layer in the thermoplastic composite film.

[0057] The conductive coating is preferably applied to the substrate by physical vapor deposition (PVD), particularly preferably by cathodic sputtering (“sputtering”), and very particularly preferably by magnetic field-assisted cathodic sputtering. The coating is preferably applied to the glass plate prior to lamination. Alternatively, in principle, the conductive coating can also be provided on a carrier film disposed in an intermediate layer, instead of being applied to the surface of the glass plate.

[0058] 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 tools) in a consistent manner, as this allows the shapes of the glass sheets to be optimally matched to each other for subsequent lamination. For example, the typical temperature for the glass bending process is 500°C to 700°C.

[0059] The present invention also includes the use of composite glass panels as windshield panels, rear glass panels, side glass panels and / or roof glass panels, particularly preferably as windshield panels for motor vehicles.

[0060] The invention will now be explained in more detail with reference to the accompanying drawings and embodiments. These drawings are schematic and not to scale. The drawings do not limit the invention in any way.

[0061] in:

[0062] Figure 1 An embodiment of the composite glass plate according to the present invention is shown, comprising a conductive coating on the outer surface of the inner glass plate and a layer of selectively absorbing nanoparticles in a thermoplastic composite film.

[0063] Figure 2a The reflection spectrum of the composite glass plate not according to the invention is shown in comparison. Figure 1 The reflectance spectrum of the composite glass plate according to the present invention was measured at 8°.

[0064] Figure 2bThe reflection spectrum of the composite glass plate not according to the invention is shown in comparison. Figure 1 The reflectance spectrum of the composite glass plate according to the present invention was measured at 60°.

[0065] Figure 3 Another embodiment of the composite glass plate according to the invention is shown, which includes a conductive coating on the inner surface of the outer glass plate and a selectively absorbing nanoparticle layer in a thermoplastic composite film.

[0066] Figure 1 A cross-section of a composite glass panel 10 according to an embodiment of the present invention is shown, which is configured as a windshield of a passenger-carrying vehicle. The composite glass panel 10 is composed of an outer glass panel 1 and an inner glass panel 2 bonded together by a thermoplastic interlayer 3. In the installation position, the outer glass panel 1 faces the external environment, and the inner glass panel 2 faces the interior space of the vehicle. The outer glass panel 1 has an outer surface I facing the external environment in the installation position and an inner surface II facing the interior space in the installation position. Similarly, the inner glass panel 2 has an outer surface III facing the external environment in the installation position and an inner surface IV facing the interior space in the installation position.

[0067] The outer glass plate 1 and the inner glass plate 2 are, for example, composed of soda-lime glass. For example, the outer glass plate 1 has a thickness of 2.1 mm, and the inner glass plate 2 has a thickness of 1.6 mm. The thermoplastic interlayer 3 is formed of a single thermoplastic composite film, such as a PVB film with a thickness of 0.76 mm.

[0068] The composite glass plate 10 also includes a conductive coating 20, which is applied to the outer surface III of the inner glass plate 2 and is configured as a heatable coating. The conductive coating 20 has a bus and a feed line (not shown) for making the coating 20 electrically contact a voltage source.

[0069] The thermoplastic interlayer 3 includes a selectively absorbing nanoparticle layer 30, wherein the nanoparticles are directly incorporated into the material of the thermoplastic composite film. CsPBI3-based nanoparticles are used as the selectively absorbing nanoparticles, exhibiting selective absorption of light in the wavelength range of 610 nm to 700 nm. The selectively absorbing nanoparticle layer 30 therefore absorbs light in the red range of the visible spectrum. This compensates for the reddish hue caused by the conductive coating 20. The outer reflected color is shifted towards blue, resulting in a more pleasing color impression.

[0070] Table 1 shows an exemplary structure of the conductive coating 20 with the materials and layer thicknesses shown. The coating 20 is applied to the inner glass plate 2, wherein the layer sequence corresponds to that shown in Table 1. The conductive coating comprises three conductive layers 21.1, 21.2, and 21.3. Each conductive layer 21 is disposed between two of a total of four antireflective layers 22.1, 22.2, 22.3, and 22.4. The antireflective layers 22.3 and 22.4 are divided into dielectric layers 22a.3 and 22a.4 and optical high-refractive-index layers 22b.3 and 22b.4, respectively. The coating 20 also comprises three smoothing layers 23.1, 23.2, and 23.3, three first adapter layers 24.1, 24.2, and 24.3, three second adapter layers 25.2, 25.3, and 25.4, and three barrier layers 26.1, 26.2, and 26.3.

[0071] Table 1

[0072] . Example

[0073] Manufacturing basis Figure 1 The composite glass plate 10 according to the invention is provided, wherein a conductive coating 20 according to Table 1 is formed. A non-invention composite glass plate is also formed as a comparative example, differing in that the selectively absorbing nanoparticle layer 30 is omitted in the comparative example. The observation results of the reflected colors (measured at angles of 8° and 60°) are summarized in Table 2. Color values ​​a* and b* in the L*a*b* color space (light source D65) are given, followed by the observation angles.

[0074] Table 2

[0075] TL / % a*(8°) b*(8°) a*(60°) b*(60°) Comparative Example 72.2 +0.5 -5.1 -1.0 +5.5 Example 71.2 -0.7 -5.4 -3.9 +4.8

[0076] As can be seen, by using the selective absorption nanoparticle layer, the a* value decreases, and the b* value also decreases slightly. Particularly at an 8° viewing angle, a change in the sign of the a* value can be observed, with the reflected color shifting from an undesirable reddish-blue hue to a greenish-blue. Therefore, the resulting color is more neutral and more pleasing to the observer. The total transmittance (light source A) exceeds 70% in both cases, thus the glass plate is suitable for use as a windshield.

[0077] Figure 2a and 2b The coating 20 shown in Table 1 is compared to the comparative composite glass plate (without the selectively absorbing nanoparticle layer). Figure 1 The reflection spectrum of the composite glass plate 10 (Example). Figure 2a The reflectance spectra measured at an observation angle of 8° are shown. Figure 2bThe spectrum has a viewing angle of 60°. The reflectance spectra of the composite glass plates according to the embodiment and the comparative example show strong deviations from each other in the wavelength range of 640 nm to 690 nm, wherein the composite glass plate according to the embodiment has an advantageously reduced reflectance in this red region of the spectrum. Therefore, the composite glass plate according to the embodiment of the invention exhibits significantly improved reflectance color at both viewing angles of 8° and 60° compared to the comparative example, wherein the color change occurs towards the green-blue direction.

[0078] Figure 3 Another embodiment of the composite glass plate 10 according to the present invention is shown, which is substantially corresponding to Figure 1 This embodiment differs from the previous one in that the conductive coating 20 is applied to the inner surface (II) of the outer glass plate 1. This embodiment is particularly preferred to achieve an attractive reflected color of the HUD image projected onto the composite glass plate 10 from the inner surface (IV). Figure 3 If the composite glass plate 10 is used as the HUD glass plate, the thermoplastic intermediate layer 3, which includes a selectively absorbing nanoparticle layer 30, is preferably manufactured as a wedge-shaped film.

[0079] List of reference numerals in the attached diagram:

[0080] (10) Composite glass plate

[0081] (1) Outer glass panel

[0082] (2) Inner glass plate

[0083] (3) Thermoplastic interlayer

[0084] (4) Opaque overprinted material

[0085] (20) Conductive coating

[0086] (21.1), (21.2), (21.3), (21.4) Conductive layers

[0087] (22.1), (22.2), (22.3), (22.4) Anti-reflective layers

[0088] (22a.3), (22a.4) Dielectric layers

[0089] (22b.3), (22b.4) Optical high-refractive-index layers

[0090] (23.1), (23.2), (23.3) Smoothing Layers

[0091] (24.1), (24.2), (24.3) First Adaptation Layer

[0092] (25.2), (25.3), (25.4) Second Adaptor Layer

[0093] (26.1), (26.2), (26.3) Barrier Layers

[0094] (30) Selective absorption nanoparticle layer

[0095] (I) The outer surface of the outer glass plate 1 facing away from the intermediate layer 3

[0096] (II) The inner surface of the outer glass plate 1 facing the intermediate layer 3

[0097] (III) The outer surface of the inner glass plate 2 facing the intermediate layer 3

[0098] (IV) The inner surface of the inner glass plate 2 facing away from the inner surface of the intermediate layer 3.

Claims

1. A composite glass plate (10) having a conductive coating (20), comprising at least an outer glass plate (1) having an outer surface (I) and an inner surface (II) and an inner glass plate (2) having an outer surface (III) and an inner surface (IV), wherein the inner surface (II) of the outer glass plate (1) and the outer surface (III) of the inner glass plate (2) are bonded to each other by a thermoplastic interlayer (3), and wherein at least the following components are stacked face-to-face between the inner surface (II) of the outer glass plate (1) and the outer surface (III) of the inner glass plate (2): - Conductive coating (20) and - At least one layer of selectively absorbing nanoparticles (30) having absorption in the wavelength range of 580 nm to 750 nm.

2. The composite glass plate (10) according to claim 1, wherein at least one selectively absorbing nanoparticle layer (30) is disposed on the outside of the conductive coating (20).

3. The composite glass plate (10) according to claim 1 or 2, wherein at least one selectively absorbing nanoparticle layer (30) is disposed inside the conductive coating (20).

4. The composite glass plate (10) according to claim 2, wherein the conductive coating (20) is disposed on the outer surface (III) of the inner glass plate (2), and the at least one selectively absorbing nanoparticle layer (30) is disposed within the intermediate layer (3).

5. The composite glass plate (10) according to claim 3, wherein the conductive coating (20) is disposed on the inner surface (II) of the outer glass plate (1), and the at least one selectively absorbing nanoparticle layer (30) is disposed within the intermediate layer (3).

6. The composite glass plate (10) according to any one of claims 1 to 2, wherein the thermoplastic intermediate layer (3) is formed of at least one thermoplastic film, and selectively absorbing nanoparticles are embedded in the at least one thermoplastic film to form a selectively absorbing nanoparticle layer (30) from the thermoplastic film, and at least 0.1% by weight of selectively absorbing nanoparticles are embedded in the at least one thermoplastic film.

7. The composite glass plate (10) according to any one of claims 1 to 2, wherein the selectively absorbing nanoparticle layer (30) comprises nanoparticles based on semiconductor materials and / or perovskite.

8. The composite glass plate (10) according to claim 7, wherein the selectively absorbing nanoparticle layer (30) comprises nanoparticles based on silicon (Si), zinc selenide (ZnSe) and / or cadmium telluride (CeTe), and / or based on halogen-containing cesium lead perovskite.

9. The composite glass plate (10) according to claim 8, wherein the selectively absorbing nanoparticle layer (30) comprises nanoparticles based on CsPbI3 or CsPb(I / Br)3.

10. The composite glass plate (10) according to any one of claims 1 to 2, wherein the selectively absorbing nanoparticle layer (30) has absorption in the wavelength range of 580 nm to 700 nm.

11. The composite glass plate (10) according to any one of claims 1 to 2, wherein the selectively absorbing nanoparticle layer (30) has an absorption of at least 20% in the absorption wavelength range.

12. The composite glass plate (10) according to any one of claims 1 to 2, wherein the conductive coating (20) comprises at least one conductive layer disposed between two dielectric layers or a sequence of layers.

13. The composite glass plate (10) according to claim 12, wherein the at least one conductive layer comprises silver.

14. The composite glass plate (10) according to any one of claims 1 to 2, wherein the conductive coating (20) has at least two buses, and the conductive coating (20) is connected to a voltage source through the buses.

15. Use of the composite glass plate (10) according to any one of claims 1 to 14 in a motor vehicle.

16. The use according to claim 15, wherein the composite glass panel (10) is used as a windshield panel, rear glass panel, side glass panel and / or top glass panel.

17. The use according to claim 15, wherein the composite glass panel (10) is used as a windshield panel for a motor vehicle.

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