Projection apparatus with p-polarized radiation for head-up display (HUD)

Abstract

Projection device for a head-up display (HUD), comprising at least - a windshield (10) comprising an outer glass pane (1) and an inner glass pane (2) connected to each other by a thermoplastic intermediate layer (3), having a HUD area (B); and - a projector (4) aimed at the HUD area (B); wherein the radiation of the projector (4) is predominantly p-polarized; and - a reflective coating (20) adapted to reflect p-polarized radiation, wherein - the reflective coating (20) comprises exactly one electrically conductive layer (21) based on silver, - the reflective coating (20) comprises below the electrically conductive layer (21) a lower dielectric layer structure (22) having a refractive index of at least 1.9, - the reflective coating (20) comprises above the electrically conductive layer (21) an upper dielectric layer structure (23) having a refractive index of at least 1.9; and - a functional coating (40) adapted to reflect IR radiation, wherein the functional coating (40) and the reflective coating (20) are arranged between the inner glass pane (2) and the outer glass pane (1), wherein the reflective coating (20) is arranged between the inner glass pane (2) and the functional coating (40).

Description

[0001] This invention relates to a projection device for a head-up display and its application.

[0002] Modern cars are increasingly equipped with what are known as head-up displays (HUDs). Using a projector, typically in the dashboard area, images are projected onto the windshield, where they are reflected and perceived by the driver as a virtual image behind the windshield (as seen by the driver). Therefore, important information, such as current speed, navigation, or warning prompts, can be projected into the driver's field of vision, allowing the driver to perceive this information without taking their eyes off the road. Thus, head-up displays can make a significant contribution to improving traffic safety.

[0003] HUD projectors primarily operate using s-polarized radiation and illuminate the windshield at an incident angle of approximately 65%, which is close to the Brewster angle of the air-glass transition (56.5° for soda-lime glass). Here, a problem arises where the projected image is reflected from both outer surfaces of the windshield. This results in a slightly misaligned secondary image, a so-called ghost image ("phantom"), in addition to the desired primary image. This problem is typically mitigated by arranging the surfaces at an angle to each other, particularly by using a wedge-shaped interlayer for laminating the windshield into a composite glass panel, thereby superimposing the primary and ghost images. Composite glass with a wedge-shaped film for HUDs is known, for example, from WO2009 / 071135A1, EP1800855B1, or EP1880243A2.

[0004] Wedge films are expensive, making the manufacture of such HUD composite glass panels quite costly. Therefore, there is a need for HUD projection devices that do not require wedge films and can be applied to windshields. For example, a HUD projector can be operated using p-polarized radiation that is substantially unreflected on the glass surface. Instead, the windshield has a reflective coating as the reflective surface for p-polarized radiation. EP3187917A2 discloses such a HUD projection device operating with p-polarized radiation. As a reflective structure, a single metal layer embedded between two dielectric layers is particularly recommended, wherein the metal layer is arranged between two single glass panels of the windshield. Alternatively, the metal layer can also be combined with a polymer layer and arranged on the outer side of the windshield.

[0005] There is a need for windshields that function in addition to reflecting p-polarized radiation. Heated coatings or coatings that reflect infrared radiation are of particular significance here. The reflective coating itself can be used as a heated coating, as disclosed in CN 106526854. However, it is difficult to combine both functions into a single coating.

[0006] CN 106630688 discloses a composite glass panel having a reflective coating for p-polarized radiation on the side of the inner glass panel facing the interior space of the vehicle, and a low-e coating on the side of the outer glass panel facing the thermoplastic interlayer. A disadvantage of this arrangement is that the p-polarized radiation reflective coating is exposed and must be protected against mechanical damage by an additional coating.

[0007] There is a need for projection devices for HUDs with reflective coatings that ensure high transmittance in the visible spectrum and high reflectivity to p-polarized radiation while providing improved thermal comfort. The object of this invention is to provide such an improved projection device.

[0008] According to the present invention, the object of the invention is achieved by the projection device according to claim 1. Preferred embodiments are known from the dependent claims.

[0009] According to the present invention, p-polarized radiation is used to generate the HUD image, and the composite glass plate has a reflective coating that sufficiently reflects p-polarized radiation. Because the typical incident angle of approximately 65° for a HUD projection device is relatively close to the Brewster angle (56.5°, soda-lime glass) of the air-glass transition, p-polarized radiation is hardly reflected by the glass surface, but primarily by the conductive coating. Therefore, no ghosting image occurs or it is almost imperceptible, thus eliminating the need for expensive wedge-shaped films. Furthermore, the HUD image is also identifiable to wearers of polarization-selective sunglasses, which typically allow only p-polarized radiation to pass through and block s-polarized radiation. The reflective coating according to the invention produces high reflectivity to p-polarized radiation in the 450 nm to 650 nm spectral range, which is relevant to HUD displays (HUD projectors typically operate at wavelengths of 473 nm, 550 nm, and 630 nm (RGB)). This achieves a high-intensity HUD image. The single-layer silver layer does not excessively reduce light transmittance, so the glass plate can continue to be used as a windshield. The functional coating significantly improves the sun protection of the glass panel by reflecting infrared (IR) radiation from sunlight. Simultaneously, the functional coating is protected from mechanical damage because it is located inside the windshield. Since the reflective coating is also located inside the windshield, it achieves the same protective effect. Placing the reflective coating between the inner glass panel and the functional coating ensures that the projector's p-polarized radiation is primarily reflected by the reflective coating, resulting in a clear HUD image for the viewer. Therefore, no interfering reflections occur on the conductive layer of the functional coating.

[0010] The projection device for a head-up display (HUD) according to the invention comprises at least one windshield with a reflective coating and a projector. As is common in HUDs, the projector illuminates an area of ​​the windshield in which radiation is reflected in the direction of the viewer (driver), thereby producing a virtual image that the viewer perceives as appearing behind the windshield. The area of ​​the windshield illuminated by the projector is called the HUD area. The beam direction of the projector can typically be changed by a mirror, particularly vertically, to match the projection to the viewer's body size. The area in which the viewer's eyes must be located at a given mirror position is called the eye-tracking range window. This eye-tracking range window can be vertically moved by adjusting the mirror, and the entire area thus accessible (i.e., the superposition of all possible eye-tracking range windows) is called the eye-tracking range. A viewer within the eye-tracking range can perceive the virtual image. Therefore, it naturally implies that the viewer's eyes, rather than, for example, the entire body, must be within the eye-tracking range.

[0011] The technical terms used here in the field of HUD are those commonly known to those skilled in the art. For a detailed explanation, see Alexander Neumann’s paper “Simulationsbasierte Messtechnik zur Prüfung von Head-Up Displays” (Munich: University Library of Technical University of Munich, 2012), especially Chapter 2, “Das Head-Up Display”.

[0012] The windshield comprises an outer glass panel and an inner glass panel, which are connected to each other by a thermoplastic interlayer. The windshield serves to separate the interior space from the external environment within a window opening of a vehicle. In the context of this invention, the inner glass panel refers to the glass panel of the windshield facing the interior space of the vehicle. The outer glass panel refers to the glass panel facing the external environment. The windshield is preferably a windshield for a motor vehicle, particularly a passenger car or truck.

[0013] A windshield has a top edge and a bottom edge, as well as two side edges extending between them. The top edge is the one that points upwards in the mounted position. The bottom edge is the one that points downwards in the mounted position. The top edge is often also called the top edge, and the bottom edge is called the engine edge.

[0014] The outer and inner glass panels each have an outer surface (outer side) and an inner space side surface (inner side) and a surrounding side edge extending between them. In the context of this invention, the outer surface or outer side refers to a main surface that is provided for facing the external environment in the installation position. Similarly, the inner space side surface or inner side refers to a main surface that is provided for facing the internal space in the installation position. The inner space side surface or inner side of the outer glass panel faces each other and is connected to each other by a thermoplastic interlayer.

[0015] The projector is aimed at the HUD area of ​​the windshield. The projector's radiation is primarily p-polarized. The reflective coating is adapted to reflect p-polarized radiation. Thus, a virtual image is generated by the projector's radiation, which the driver of the vehicle can perceive as appearing behind the windshield.

[0016] The reflective coating according to the invention has exactly one silver-based conductive layer. A lower dielectric layer structure is disposed below the conductive layer. The lower dielectric layer structure may consist of a single dielectric layer or comprise a sequence of multiple layers. Similarly, an upper dielectric layer structure is disposed above the conductive layer. The upper dielectric layer structure may consist of a single dielectric layer or comprise a sequence of multiple layers. Both the upper and lower dielectric layer structures have a refractive index of at least 1.9.

[0017] Within the scope of this invention, the refractive index is, in principle, given based on a wavelength of 550 nm. For example, the refractive index can be determined using ellipsometrics. Ellipsometrists are commercially available, for example, from Sentech. The refractive index of the upper or lower dielectric layer is preferably determined by first depositing it as a monolayer on the substrate and then measuring the refractive index using ellipsometrics. To determine the refractive index of the upper or lower dielectric layer sequence, each layer of the layer sequence is deposited individually as a monolayer on the substrate, and then the refractive index is determined using ellipsometrics. According to the invention, a refractive index of at least 1.9 can be achieved for each of these monolayers. In the case of a layer sequence having a refractive index of at least 1.9, all individual layers therefore have a refractive index of at least 1.9. Dielectric layers with a refractive index of at least 1.9 and their deposition methods are known to those skilled in the art of thin layers. Physical vapor deposition methods are preferred, particularly magnetron sputtering. The optical thickness is the product of the geometric thickness and the refractive index (at 550 nm). The optical thickness of the layer sequence is calculated as the sum of the optical thicknesses of each individual layer.

[0018] If the first layer (or layer sequence, layer module, or layer structure) is arranged above the second layer, this means, in the sense of the invention, that the first layer is arranged further away from the substrate on which the coating is applied than the second layer. If the first layer is arranged below the second layer, this means, in the sense of the invention, that the second layer is arranged further away from the substrate than the first layer.

[0019] If a layer is formed based on a material, then the layer is mostly composed of that material, especially except for possible impurities or dopants.

[0020] The reflective coating is transparent, which in the sense of this invention means that it has an average transmittance of at least 70%, preferably at least 80%, in the visible spectrum range, and thus does not substantially restrict the visibility through it. In principle, it is sufficient if the HUD area of ​​the windshield has a reflective coating. However, other areas may also have a reflective coating, and the windshield may have a reflective coating on substantially the entire surface, which may be preferred for manufacturing reasons. In one embodiment of the invention, at least 80% of the glass panel surface has a reflective coating according to the invention. In particular, the reflective coating is applied to the entire surface of the glass panel, except for the surrounding edge areas and optionally localized areas that, as communication windows, sensor windows, or camera windows, should ensure that electromagnetic radiation is transmitted through the windshield and therefore do not have a reflective coating. The surrounding uncoated edge areas, for example, have a width of at most 20 cm. This prevents the reflective coating from direct contact with the surrounding atmosphere, thereby protecting the reflective coating inside the windshield from corrosion and damage.

[0021] The functional coating possesses IR reflective properties, thus it is used as a sun-protective coating, reducing heating of the vehicle's interior space by reflecting thermal radiation. The TTS value of the coated composite glass panel is preferably less than 60%, particularly preferably less than 55%. The TTS value represents the total amount of solar energy incident, measured according to ISO 13837—a measure of thermal comfort. The coating can also be used as a heating coating if it is brought into electrical contact, allowing current to flow through it and heating the coating. The film resistivity of the coating is preferably less than 4 Ω / □, particularly less than 3 Ω / □.

[0022] The reflective coating is preferably applied directly to the surface of the inner glass panel facing the thermoplastic interlayer, i.e., the outer surface (outer side) of the inner glass panel. The advantage of applying it directly to the outer side of the inner glass panel, rather than through a carrier film, is the absence of optical damage caused by the carrier film. This visually perfect arrangement is particularly significant for future use in HUD projection devices. The reflective coating is preferably applied via physical vapor deposition. This provides a particularly good coating and is easy to implement industrially.

[0023] The functional coating is preferably applied directly to the inner side of the outer glass plate facing the thermoplastic interlayer. This placement on the inner side of the outer glass plate prevents overheating. The functional coating is particularly preferably applied to the outer glass plate via physical vapor deposition. This provides a particularly good coating and is easy to implement industrially.

[0024] The functional coating is preferably applied directly to the inside of the outer glass pane and the reflective coating is applied directly to the outside of the inner glass pane. This is particularly easy to manufacture industrially because it eliminates the need for a separate carrier film. Furthermore, it avoids optical defects that may occur during the lamination of the windshield.

[0025] Furthermore, the functional coating or reflective coating is preferably disposed on a polymer carrier film. The carrier film is disposed between the outer glass plate and the inner glass plate. The carrier film is preferably embedded in a thermoplastic interlayer. In this way, optimal bonding between the inner and outer glass plates is achieved.

[0026] The reflective coating is preferably applied directly to the inner glass plate, and the functional coating is embedded in a thermoplastic interlayer on the carrier film. This avoids optical damage caused by the carrier film or thermoplastic interlayer when generating HUD images.

[0027] The functional coating and reflective coating are preferably applied to a carrier film, particularly a single polymer carrier film, which contains the functional coating on one side and the reflective coating on the other. This is advantageous in terms of process technology, as only a single film needs to be co-laminated. Furthermore, in this case, the distance between the reflective and functional coatings is determined solely by the thickness of the polymer carrier film. When p-polarized radiation is reflected from the functional coating, the resulting image overlaps with the reflection from the reflective coating, thus eliminating the perception of two separate HUD images. In this way, interfering ghosting images are effectively suppressed.

[0028] The carrier membrane is preferably composed of polyethylene terephthalate (PET).

[0029] The thickness of the carrier film is preferably 30 μm to 400 μm, more preferably 40 μm to 200 μm, and particularly preferably 50 μm to 150 μm, for example 100 μm. This is particularly advantageous in the case of a double-coated carrier film, because the ghosting generated by reflections on the functional coating overlaps with the HUD image to form a single image, thus eliminating the perception of interfering ghosting.

[0030] In a preferred embodiment, the functional coating includes at least one silver-based conductive layer. The geometric thickness of the conductive layer in the functional coating is smaller than the geometric thickness of the silver-based conductive layer in the reflective coating. Due to the smaller geometric thickness of the silver-based conductive layer in the functional coating compared to the thickness of the conductive layer in the reflective coating, high windshield transmittance is ensured, resulting in a clear HUD image.

[0031] This difference is preferably 1 nm to 10 nm, more preferably 2 nm to 6 nm, and particularly preferably 3 nm to 4 nm. In the case of multiple conductive layers in the functional coating, this difference in each case refers to the difference between a single layer of the functional coating and a layer in the reflective coating. Because the conductive layer in the functional coating is relatively thin, sufficient transmittance of the windshield can be ensured. Furthermore, the weak ghosting caused by the functional layer is only slightly noticeable.

[0032] The functional coating preferably comprises at least one silver-based conductive layer. A bottom dielectric layer module is disposed below the conductive layer. The bottom dielectric layer module may consist of a single dielectric layer or comprise a sequence of multiple dielectric layers. Similarly, a top dielectric layer module is disposed above the conductive layer. The top dielectric layer module may consist of a single dielectric layer or comprise a sequence of multiple dielectric layers. Both the top and bottom dielectric layer modules have a refractive index of at least 1.9. The terms top and bottom layer modules mean that, in the functional coating, no additional dielectric layer module is disposed above the top layer module or below the bottom dielectric layer module.

[0033] In a preferred embodiment, the functional coating includes at least one silver-based conductive layer. The geometric thickness of the conductive layer in the functional coating is smaller than the geometric thickness of the silver-based conductive layer in the reflective coating. Due to the smaller geometric thickness of the silver-based conductive layer in the functional coating compared to the conductive layer in the reflective coating, high transmittance of the windshield is ensured, resulting in a clear HUD image. The functional coating preferably includes at least one silver-based conductive layer. A bottom dielectric layer module is disposed below the conductive layer. The bottom dielectric layer module may consist of a single dielectric layer or comprise a sequence of multiple dielectric layers. Similarly, an uppermost dielectric layer module is disposed above the conductive layer. The uppermost dielectric layer module may consist of a single dielectric layer or comprise a sequence of multiple dielectric layers. Both the uppermost and lowermost dielectric layer modules have a refractive index of at least 1.9.

[0034] Due to one or more conductive silver layers, the functional coating preferably has IR reflective properties, thus serving as a sun-protective coating that reduces heating of the vehicle's interior space by reflecting thermal radiation. The functional coating is also preferably used as a heating coating, wherein it is brought into electrical contact so that current flows through it, heating the functional coating. Here, the functional coating is connected to a voltage source via an electrical busbar and can be heated by applying voltage.

[0035] The functional coating is transparent, which in the sense of this invention means that it has an average transmittance of at least 70%, preferably at least 80%, in the visible spectrum, and thus substantially does not restrict the visibility through it. The windshield preferably has a functional coating substantially over its entire surface. This provides full-surface sun protection and is preferred for manufacturing reasons. In one embodiment of the invention, at least 80% of the glass panel surface has a functional coating. Particularly preferably, the functional coating is applied to the entire surface of the glass panel, except for surrounding edge areas and optionally localized areas that, as communication windows, sensor windows, or camera windows, should ensure electromagnetic radiation transmission through the windshield and therefore do not have a functional coating. The surrounding uncoated edge areas, for example, have a width of at most 20 cm. This prevents the functional coating from direct contact with the surrounding atmosphere, thereby protecting the functional coating inside the windshield from corrosion and damage.

[0036] In a preferred embodiment, the ratio of the optical thickness of the upper dielectric layer structure to the optical thickness of the lower dielectric layer structure in the reflective coating is at least 1.6. Surprisingly, this asymmetry in optical thickness produces a significantly smoother reflection spectrum for p-polarized radiation, resulting in a relatively constant reflectance across the entire relevant spectral range (400 nm to 680 nm). This ensures a color-neutral display of the HUD projection. Particularly preferably, the ratio of the optical thickness of the upper dielectric layer structure to the optical thickness of the lower dielectric layer structure is at least 1.7, and more preferably at least 1.8. This yields particularly good results.

[0037] The ratio of optical thicknesses is calculated as the quotient of the optical thickness (dividend) of the upper dielectric layer structure divided by the optical thickness (divisor) of the lower dielectric layer structure.

[0038] In a preferred embodiment, the ratio of the optical thickness of the uppermost dielectric layer module to the optical thickness of the lowermost dielectric layer module in the functional coating is 0.8 to 2. Surprisingly, this ratio results in a particularly high windshield transmittance value. The ratio of the optical thickness of the uppermost dielectric layer module to the optical thickness of the lowermost dielectric layer module is preferably 0.8 to 1.5, particularly preferably 0.9 to 1.2, and especially approximately 1.0. This achieves particularly good transmission performance.

[0039] The ratio of optical thicknesses is calculated as the quotient of the optical thickness (dividend) of the uppermost dielectric layer module divided by the optical thickness (divisor) of the lowermost dielectric layer module.

[0040] In a preferred embodiment, the functional coating comprises two silver-based conductive layers and an intermediate dielectric layer module between them. This improves IR reflection performance, thereby achieving improved thermal protection. The intermediate dielectric layer module is disposed between the two silver-based conductive layers, so the functional coating sequentially comprises the following layers: bottom dielectric layer module – first silver-based conductive layer – intermediate dielectric layer module – second silver-based conductive layer – top dielectric layer module. Other layers may be included in the layer stack.

[0041] In the functional coating, the ratio of the optical thickness of the intermediate dielectric layer module to the optical thickness of the bottom dielectric layer module and to the optical thickness of the top dielectric layer module is preferably greater than 1.9, particularly preferably greater than 2.0 and particularly preferably greater than 2.1. The inventors have discovered that, despite the increase in the amount of silver layer, this ratio results in a surprisingly high transmittance value for the windshield. Preferably, this ratio is not greater than 3.0.

[0042] Therefore, this involves the following optical thickness ratios: Middle dielectric layer module / bottom dielectric layer module Middle dielectric layer module / Top dielectric layer module Preferably, in the functional coating, the ratio of the optical thickness of the uppermost dielectric layer module to the optical thickness of the lowermost dielectric layer module is 0.9 to 1.1, preferably about 1, and the ratio of the optical thickness of the intermediate dielectric layer module to the optical thickness of the lowermost dielectric layer module and to the optical thickness of the uppermost dielectric layer module is greater than 1.9, particularly preferably greater than 2.0, and particularly preferably greater than 2.1. This combination leads to particularly good results.

[0043] In another preferred embodiment, the functional coating comprises three silver-based conductive layers and two intermediate dielectric layer modules disposed between the three silver-based conductive layers. This further improves infrared reflectivity, thereby achieving enhanced thermal protection. The two intermediate dielectric layer modules are arranged such that one intermediate dielectric layer module is disposed between every two silver layers. Therefore, the functional coating sequentially comprises the following layers: bottom dielectric layer module – first silver-based conductive layer – intermediate dielectric layer module – second silver-based conductive layer – intermediate dielectric layer module – third silver-based conductive layer – top dielectric layer module. Additional layer stacks may also be included in the layer stack. More than three silver-based conductive layers may also be present, in which case additional intermediate dielectric layer modules are added, such that the silver layers are isolated from each other by the dielectric layer modules.

[0044] Preferably, in the functional coating, the ratio of the optical thickness of the two intermediate dielectric layer modules to the optical thickness of the bottom dielectric layer module and the optical thickness of the top dielectric layer module is greater than 1.9, more preferably greater than 2.0, and particularly preferably greater than 2.1. Therefore, this relates to the following optical thickness ratios: First intermediate dielectric layer module / bottommost dielectric layer module Second intermediate dielectric layer module / bottommost dielectric layer module First intermediate dielectric layer module / Topmost dielectric layer module Second intermediate dielectric layer module / Top dielectric layer module.

[0045] Preferably, in the functional coating, the ratio of the optical thickness of the uppermost dielectric layer module to the optical thickness of the lowermost dielectric layer module is 0.9 to 1.1, preferably about 1, and the ratio of the optical thickness of the intermediate dielectric layer module to the optical thickness of the lowermost dielectric layer module and to the optical thickness of the uppermost dielectric layer module is greater than 1.9, particularly preferably greater than 2.0, and particularly preferably greater than 2.1. This combination leads to particularly good results.

[0046] In another preferred embodiment, the functional coating comprises at least two, preferably exactly two, exactly three, or exactly four silver-based conductive layers, wherein each silver-based conductive layer in the functional coating has a thinner geometric thickness than the silver-based conductive layers in the reflective coating. This results in improved thermal protection for the windshield while maintaining high transmittance, thereby preventing intrusive ghosting images caused by reflections on the conductive layers of the functional coating.

[0047] The reflective coating is a thin-layer stack, i.e., a sequence of thin, single-layered structures. This thin-layer stack contains exactly one silver-based conductive layer. This silver-based conductive layer imparts basic reflective properties to the reflective coating, as well as IR reflection and conductivity. This silver-based conductive layer can also be simply referred to as a silver layer. The reflective coating contains exactly one silver layer, i.e., no more than one silver layer. A particular advantage of this invention is that the desired reflective properties can be obtained with a silver layer without a significant reduction in transmittance, as is the case when multiple conductive layers are used in the reflective coating. However, additional conductive layers may exist that do not significantly contribute to the conductivity of the reflective coating but serve other purposes. This is particularly suitable for metal barrier layers with a geometric thickness of less than 1 nm, preferably disposed between the silver layer and the dielectric layer structure.

[0048] The conductive layer in the functional coating and reflective coating is formed based on silver. The conductive layer preferably contains at least 90% by weight of silver, particularly preferably at least 99% by weight of silver, and very particularly preferably at least 99.9% by weight of silver. The silver layer may have dopants, such as palladium, gold, copper, or aluminum.

[0049] The geometric thickness of the silver layer in the reflective coating is preferably at most 15 nm, particularly preferably at most 14 nm, and very particularly preferably at most 13 nm. This results in favorable reflectivity in the IR range without drastically reducing transmittance. The geometric thickness of the silver layer is preferably at least 5 nm, particularly preferably at least 8 nm. A thinner silver layer can lead to dehumidification of the layer structure. The geometric thickness of the silver layer is particularly preferably from 10 nm to 14 nm or from 11 nm to 13 nm.

[0050] The geometric thickness of each silver layer in the functional coating is preferably at most 12 nm, particularly preferably at most 10 nm, and especially preferably about 8 nm. This results in high reflectivity in the IR range without excessively reducing transmittance.

[0051] In an advantageous embodiment, the reflective coating does not include a dielectric layer with a refractive index less than 1.9. Therefore, all dielectric layers of the reflective coating have a refractive index of at least 1.9. A particular advantage of the invention is that the desired reflective properties can be achieved using only relatively high-refractive-index dielectric layers. Since silicon oxide layers with low deposition rates in magnetic field-assisted cathodic deposition are particularly suitable for low-refractive-index layers less than 1.9, the reflective coating according to the invention can be fabricated quickly and cost-effectively.

[0052] In an advantageous embodiment, the functional coating does not include a dielectric layer with a refractive index less than 1.9. Therefore, all dielectric layers of the functional coating have a refractive index of at least 1.9. A particular advantage is that low-refractive-index layers (especially silicon oxide layers) with a refractive index less than 1.9 are not required because they have low deposition rates in magnetic field-assisted cathodic deposition. Therefore, windshields according to the invention can be manufactured quickly and cost-effectively.

[0053] Functional coatings and reflective coatings preferably do not include dielectric layers with a refractive index of less than 1.9.

[0054] The reflective coating comprises two independent dielectric layer structures, one above and one below the silver layer, each with a refractive index of at least 1.9. The dielectric layers contained within these structures can be formed, for example, based on silicon nitride, zinc oxide, tin-zinc oxide, silicon-metal-mixed nitrides such as silicon-zirconium nitride, zirconium oxide, niobium oxide, hafnium oxide, tantalum oxide, tungsten oxide, or silicon carbide. The aforementioned oxides and nitrides can be deposited stoichiometric, substoichiometric, or superstoichiometrically. They can be doped with, for example, aluminum, zirconium, titanium, or boron. Layers of these materials with a refractive index of at least 1.9 in monolayer form are known and can be obtained by those skilled in the art using known methods. Physical vapor deposition methods, particularly magnetron sputtering, are preferred for depositing these layers.

[0055] The optical thickness of the upper dielectric layer structure is preferably 80 nm to 200 nm, and particularly preferably 100 nm to 130 nm. The optical thickness of the lower dielectric layer structure is preferably 50 nm to 100 nm, and particularly preferably 60 nm to 90 nm. This yields good results.

[0056] In an advantageous embodiment, a dielectric layer, which may be referred to as an antireflective layer, is disposed above and below the silver layer in the reflective coating, and is preferably based on an oxide, such as tin oxide, and / or a nitride, such as silicon nitride, particularly preferably silicon nitride. Silicon nitride has proven advantageous due to its optical properties, its availability, and its high mechanical and chemical stability. Silicon is preferably doped with, for example, aluminum or boron. In the case of the dielectric layer sequence, the silicon nitride-based layer is preferably the uppermost layer of the upper layer sequence or the lowermost layer of the lower layer sequence. The geometric thickness of the upper antireflective layer is preferably 20 nm to 100 nm, particularly preferably 40 nm to 60 nm, and especially 30 nm to 50 nm. The geometric thickness of the lower antireflective layer is preferably 10 nm to 50 nm, particularly preferably 15 nm to 40 nm, and especially 20 nm to 35 nm.

[0057] In addition to eliminating the reflective layer, an additional dielectric layer with a refractive index of at least 1.9 may optionally be present in the dielectric layer structure. Therefore, the upper and lower dielectric layer structures can independently include adapter layers to improve the reflectivity of the silver layer. The adapter layer is preferably based on zinc oxide, and particularly preferably zinc oxide (ZnO). 1-δ Formed, of which 0 < δ < 0.01. The adapter layer further preferably contains dopants. The adapter layer may contain, for example, aluminum-doped zinc oxide (ZnO:Al). To avoid excessive oxygen reacting with the silver-containing layer, zinc oxide is preferably deposited in a substoichiometric manner relative to oxygen. The adapter layer is preferably disposed between the silver layer and the antireflective layer. The geometric thickness of the adapter layer is preferably 5 nm to 30 nm, particularly preferably 8 nm to 12 nm.

[0058] A refractive index-enhancing layer, having a higher refractive index than the antireflective layer, can also be present in the reflective coating, independently of the upper and lower dielectric layer structures. This allows for further improvement and fine-tuning of optical properties. The refractive index-enhancing layer preferably comprises a silicon-metal-mixed nitride, such as a silicon-zirconium-mixed nitride, a silicon-aluminum-mixed nitride, a silicon-titanium-mixed nitride, or a silicon-hafnium-mixed nitride, with a particularly preferred silicon-zirconium-mixed nitride. Here, the proportion of zirconium is preferably 15 to 45% by weight, particularly preferably 15 to 30% by weight. Alternative materials such as WO3, Nb2O5, Bi2O3, TiO2, and / or AlN can be considered. The refractive index-enhancing layer is preferably disposed between the antireflective layer and the silver layer, or between the adapter layer (if present) and the antireflective layer. The geometric thickness of the refractive index-enhancing layer is preferably 5 nm to 30 nm, particularly preferably 5 nm to 15 nm.

[0059] In a preferred embodiment of the invention, in the reflective coating, a lower dielectric layer with a refractive index of at least 1.9, preferably based on silicon nitride, is disposed below the conductive layer. This means that the lower dielectric layer structure consists of exactly one lower dielectric layer. Similarly, an upper dielectric layer with a refractive index of at least 1.9, preferably based on silicon nitride, is disposed above the conductive layer. This means that the upper dielectric layer structure consists of exactly one upper dielectric layer. This results in a layer sequence starting from the substrate: lower anti-reflective layer – silver layer – upper anti-reflective layer. The reflective coating preferably does not contain any additional dielectric layers. The geometric thickness of the upper anti-reflective layer is preferably 20 nm to 100 nm, particularly preferably 40 nm to 60 nm, and especially 30 nm to 50 nm. The geometric thickness of the lower anti-reflective layer is preferably 10 nm to 50 nm, particularly preferably 15 nm to 40 nm, and especially 20 nm to 35 nm.

[0060] In another preferred embodiment of the invention, in the reflective coating, a first lower dielectric layer (anti-reflection layer) and a second lower dielectric layer (adapter layer) are disposed below the conductive layer. This means that the lower layer structure includes the first lower dielectric layer and the second lower dielectric layer. Similarly, a first upper dielectric layer (anti-reflection layer) and a second upper dielectric layer (adapter layer) are disposed above the conductive layer. This means that the upper layer structure includes or is composed of the first upper dielectric layer and the second upper dielectric layer. The refractive index of the anti-reflection layer and the adapter layer is at least 1.9. The anti-reflection layer is preferably formed based on silicon nitride, and the adapter layer is based on zinc oxide. The adapter layer is preferably disposed between the respective anti-reflection layer and the silver layer, creating a layer sequence from the substrate as follows: lower anti-reflection layer – lower adapter layer – silver layer – upper adapter layer – upper anti-reflection layer. The reflective coating preferably does not contain any additional dielectric layer. The geometric thickness of the upper anti-reflective layer is preferably 20 nm to 100 nm, particularly preferably 40 nm to 60 nm, and especially preferably 30 nm to 50 nm. The geometric thickness of the lower anti-reflective layer is preferably 10 nm to 50 nm, particularly preferably 15 nm to 40 nm, and especially preferably 20 nm to 35 nm. The geometric thickness of the adapter layer is preferably 5 nm to 30 nm, and especially preferably 8 nm to 12 nm.

[0061] In another embodiment of the invention, in the reflective coating, a first lower dielectric layer (anti-reflection layer), a second lower dielectric layer (adapter layer), and a third lower dielectric layer (refractive index increasing layer) are disposed below the conductive layer. This means that the lower layer structure includes or is composed of the first lower dielectric layer, the second lower dielectric layer, and the third lower dielectric layer. Similarly, a first upper dielectric layer (anti-reflection layer), a second upper dielectric layer (adapter layer), and a third upper dielectric layer (refractive index increasing layer) are disposed above the conductive layer. This means that the upper layer structure includes or is composed of the first upper dielectric layer, the second upper dielectric layer, and the third upper dielectric layer. The refractive index of the anti-reflection layer, the adapter layer, and the refractive index increasing layer is at least 1.9. The refractive index increasing layer has a higher refractive index than the anti-reflection layer, preferably at least 2.1. The antireflective layer is preferably formed based on silicon nitride, the adapter layer is based on zinc oxide, and the refractive index increasing layer is based on a silicon-metal-mixed nitride, such as a silicon-zirconium-mixed nitride or a silicon-hafnium-mixed nitride. The adapter layer preferably has a minimal distance from the silver layer, while the refractive index increasing layer is disposed between the adapter layer and the antireflective layer. This results in a layer sequence starting from the substrate: lower antireflective layer – lower refractive index increasing layer – lower adapter layer – silver layer – upper adapter layer – upper refractive index increasing layer – upper antireflective layer. The reflective coating preferably does not contain an additional dielectric layer. The geometric thickness of the upper antireflective layer is preferably 20 nm to 100 nm, particularly preferably 40 nm to 60 nm, and especially 30 nm to 50 nm. The geometric thickness of the lower antireflective layer is preferably 10 nm to 50 nm, particularly preferably 15 nm to 40 nm, and especially 20 nm to 35 nm. The geometric thickness of the adaptor layer is preferably 5 nm to 30 nm, and particularly preferably 8 nm to 12 nm. The geometric thickness of the refractive index increasing layer is preferably 5 nm to 30 nm, and particularly preferably 5 nm to 15 nm.

[0062] Since the lower and upper layer structures can be formed independently of each other, combinations of the above embodiments are also feasible, wherein an upper dielectric layer structure is formed according to one embodiment and a lower dielectric layer structure is formed according to another embodiment. The following preferred layer sequence is produced (in each case starting from the substrate, i.e., from the surface on which the reflective coating is deposited): - Lower anti-reflective layer – Silver layer – Upper anti-reflective layer - Lower anti-reflective layer – Silver layer – Upper adapter layer – Upper anti-reflective layer - Lower anti-reflective layer – Silver layer – Upper adapter layer – Upper refractive index increasing layer – Upper anti-reflective layer - Lower anti-reflective layer – Lower adapter layer – Silver layer – Upper anti-reflective layer - Lower anti-reflective layer – Lower adapter layer – Silver layer – Upper adapter layer – Upper anti-reflective layer - Lower anti-reflective layer – Lower adapter layer – Silver layer – Upper adapter layer – Upper refractive index increasing layer – Upper anti-reflective layer - Lower anti-reflective layer – Lower refractive index increasing layer – Lower adapter layer – Silver layer – Upper anti-reflective layer - Lower anti-reflective layer – Lower refractive index increasing layer – Lower adapter layer – Silver layer – Upper adapter layer – Upper anti-reflective layer - Lower anti-reflective layer – Lower refractive index increasing layer – Lower adapter layer – Silver layer – Upper adapter layer – Upper refractive index increasing layer – Upper anti-reflective layer In an advantageous embodiment of the invention, the reflective coating includes at least one metallic barrier layer. This barrier layer may be disposed below and / or above the silver layer, and preferably in direct contact with the silver layer. The barrier layer is then positioned between the silver layer and the dielectric layer structure. The barrier layer serves to protect the silver layer from oxidation, particularly when the coated glass plate is subjected to temperature treatments, such as those typically occurring in bending processes. The geometric thickness of the barrier layer is preferably less than 1 nm, for example, 0.1 nm to 0.5 nm. The barrier layer is preferably formed based on titanium or a nickel-chromium alloy.

[0063] The barrier layer negligibly alters the optical properties of the reflective coating and is preferably present in all the embodiments described above. Particularly preferably, the barrier layer is disposed directly above the silver layer, i.e., between the silver layer and the upper dielectric layer structure, where it is particularly effective. This results in the following preferred layer sequence: - Lower anti-reflective layer – Silver layer – Barrier layer – Upper anti-reflective layer - Lower anti-reflective layer – Silver layer – Barrier layer – Upper adapter layer – Upper anti-reflective layer - Lower anti-reflective layer – Silver layer – Barrier layer – Upper adapter layer – Upper refractive index increasing layer – Upper anti-reflective layer - Lower anti-reflective layer – Lower adapter layer – Silver layer – Barrier layer – Upper anti-reflective layer - Lower anti-reflective layer – Lower adapter layer – Silver layer – Barrier layer – Upper adapter layer – Upper anti-reflective layer - Lower anti-reflective layer – Lower adapter layer – Silver layer – Barrier layer – Upper adapter layer – Upper refractive index increasing layer – Upper anti-reflective layer - Lower anti-reflective layer – Lower refractive index increasing layer – Lower adapter layer – Silver layer – Barrier layer – Upper anti-reflective layer - Lower anti-reflective layer – Lower refractive index increasing layer – Lower adapter layer – Silver layer – Barrier layer – Upper adapter layer – Upper anti-reflective layer - Lower anti-reflective layer – Lower refractive index increasing layer – Lower adapter layer – Silver layer – Barrier layer – Upper adapter layer – Upper refractive index increasing layer – Upper anti-reflective layer In each case, the additional barrier layer may optionally be disposed directly below the silver layer, i.e., between the silver layer and the underlying dielectric layer structure.

[0064] The functional coating comprises, independently above and below, a dielectric layer module with a refractive index of at least 1.9. In the case of a functional coating with multiple silver layers, all dielectric layer modules preferably have a refractive index of at least 1.9. The dielectric layers contained in the dielectric layer modules can be formed, for example, based on silicon nitride, zinc oxide, tin-zinc oxide, silicon-metal mixed nitrides such as silicon-zirconium nitride, zirconium oxide, niobium oxide, hafnium oxide, tantalum oxide, tungsten oxide, or silicon carbide. The aforementioned oxides and nitrides can be deposited stoichiometrically, substoichiometrically, or superstoichiometrically. They can be doped, for example with aluminum, zirconium, titanium, or boron.

[0065] The optical thickness of the uppermost dielectric layer module is preferably 70 nm to 200 nm, particularly preferably 80 nm to 100 nm. The optical thickness of the lowermost dielectric layer module is preferably 70 nm to 100 nm, particularly preferably 80 nm to 150 nm. This yields good results. The optical thickness of the middle dielectric layer module is preferably 100 nm to 400 nm, more preferably 150 nm to 300 nm, and particularly preferably 160 nm to 200 nm.

[0066] In an advantageous embodiment, in the functional coating, in the uppermost and lowermost layer modules, and, if present, in the intermediate layer modules, a dielectric layer, which may be referred to as an anti-reflection layer, is arranged, preferably based on an oxide such as tin oxide and / or a nitride such as silicon nitride, particularly preferably based on silicon nitride. Silicon nitride is proven to be beneficial due to its optical properties, its availability, and its high mechanical and chemical stability. Silicon is preferably doped with, for example, aluminum or boron.

[0067] In the case of the uppermost and lowermost layer modules, the silicon nitride-based layer is preferably the uppermost layer of the uppermost layer module or the lowermost layer of the uppermost layer module. The geometric thickness of the anti-reflection layer in the uppermost and lowermost layer modules is preferably 10 nm to 50 nm, particularly preferably 15 nm to 40 nm, and especially 20 nm to 35 nm. The geometric thickness of the anti-reflection layer in the intermediate layer modules is preferably 30 nm to 100 nm, particularly preferably 40 nm to 80 nm, and especially 50 nm to 70 nm.

[0068] In addition to the anti-reflective layer, an additional dielectric layer with a refractive index of at least 1.9 may optionally be present in the dielectric layer module. Therefore, the uppermost and lowermost dielectric layer modules can independently contain adapter layers to improve the reflectivity of the silver layer. The intermediate layer modules can independently contain one or two adapter layers. The adapter layers are preferably based on zinc oxide, and particularly preferably zinc oxide (ZnO). 1-δ Formed, of which 0 < δ < 0.01. The adapter layer further preferably contains dopants. The adapter layer may contain, for example, aluminum-doped zinc oxide (ZnO:Al). To avoid excessive oxygen reacting with the silver-containing layer, zinc oxide is preferably deposited in a substoichiometric manner relative to oxygen. In the uppermost and lowermost dielectric layer modules, the adapter layer is preferably disposed between the silver layer and the antireflection layer. In the intermediate dielectric layer modules, the adapter layer is preferably disposed between adjacent silver layers and the antireflection layer. The geometric thickness of the adapter layer is preferably from 5 nm to 30 nm, particularly preferably from 8 nm to 12 nm.

[0069] A refractive index-enhancing layer, having a higher refractive index than the antireflective layer, may also be present in the functional coating, independently of each other in the uppermost, lowermost, and optionally intermediate dielectric layer modules. This allows for further improvement and fine-tuning of optical properties. The refractive index-enhancing layer preferably comprises a silicon-metal-mixed nitride, such as a silicon-zirconium-mixed nitride, a silicon-aluminum-mixed nitride, a silicon-titanium-mixed nitride, or a silicon-hafnium-mixed nitride, with a particular preference for a silicon-zirconium-mixed nitride. Here, the proportion of zirconium is preferably 15 to 45% by weight, particularly preferably 15 to 30% by weight. Alternative materials may be considered, for example, WO3, Nb2O5, Bi2O3, TiO2, and / or AlN. The refractive index-enhancing layer is preferably disposed between the antireflective layer and the silver layer or between the adapter layer (if present) and the antireflective layer. The geometric thickness of the refractive index-enhancing layer is preferably 5 nm to 30 nm, particularly preferably 5 nm to 15 nm.

[0070] In a preferred embodiment of the invention, the bottommost layer module of the functional coating consists of exactly one lower dielectric layer with a refractive index of at least 1.9, preferably based on silicon nitride. Similarly, the topmost layer module consists of exactly one upper dielectric layer module with a refractive index of at least 1.9, preferably based on silicon nitride. The functional coating preferably does not contain any other dielectric layers. The geometric thickness of the antireflective layers in the topmost and bottommost layer modules is preferably 10 nm to 50 nm, particularly preferably 15 nm to 40 nm, especially 20 nm to 35 nm. The geometric thickness of the antireflective layers in the intermediate dielectric layer modules is preferably 50 nm to 100 nm, particularly preferably 55 nm to 80 nm, especially 60 nm to 70 nm.

[0071] In another preferred embodiment of the invention, the first dielectric layer (anti-reflection layer) and the second dielectric layer (adapter layer) are arranged independently of each other in the bottommost layer module, the topmost layer module, and the intermediate layer module. The refractive index of the anti-reflection layer and the adapter layer is at least 1.9. The anti-reflection layer is preferably formed based on silicon nitride, and the adapter layer is formed based on zinc oxide. The adapter layer is preferably arranged between the respective anti-reflection layer and the silver layer. The functional coating preferably does not contain any other dielectric layers.

[0072] The uppermost and lowermost layer modules particularly preferably comprise an anti-reflection layer and an adapter layer, and have no other dielectric layers. The middle layer modules preferably comprise a lower adapter layer, an anti-reflection layer, and an upper adapter layer in sequence, and have no other dielectric layers. The geometric thickness of the anti-reflection layer in the uppermost and lowermost layer modules is preferably 10 nm to 50 nm, particularly preferably 15 nm to 40 nm, and especially 20 nm to 35 nm. The anti-reflection layer in the middle layer modules is preferably 30 nm to 100 nm, particularly preferably 40 nm to 80 nm, and especially 50 nm to 70 nm. The geometric thickness of the adapter layer is preferably 5 nm to 30 nm, particularly preferably 8 nm to 12 nm.

[0073] In another preferred embodiment of the invention, in the functional coating, a first dielectric layer (anti-reflection layer), a second dielectric layer (adapter layer), and a third dielectric layer (refractive index increasing layer) are arranged independently in the bottommost and topmost layer modules. Preferably, no additional dielectric layers are arranged in the bottommost and topmost layer modules. The first dielectric layer (adapter layer), the second dielectric layer (anti-reflection layer), and the third dielectric layer (adapter layer) are preferably arranged in the intermediate layer modules. The anti-reflection layer, the adapter layer, and the refractive index increasing layer have a refractive index of at least 1.9. The refractive index increasing layer has a higher refractive index than the anti-reflection layer, preferably at least 2.1. The anti-reflection layer is preferably formed based on silicon nitride, the adapter layer is based on zinc oxide, and the refractive index increasing layer is based on a silicon-metal-mixed nitride, such as a silicon-zirconium mixed nitride or a silicon-hafnium mixed nitride. The adapter layer is preferably located at the smallest distance from the silver layer, while the refractive index increasing layer is arranged between the adapter layer and the anti-reflection layer. The top and bottom layer modules are produced with the following layer sequence starting from the substrate: (substrate) - antireflective layer - adapter layer - refractive index increasing layer - (silver). The middle layer modules are produced with the following layer sequence starting from the silver layer: (silver) - adapter layer - antireflective layer - adapter layer - (silver). The functional coating preferably does not contain other dielectric layers. The geometric thickness of the antireflective layer in the top and bottom layer modules is preferably 10 nm to 50 nm, particularly preferably 15 nm to 40 nm, especially 20 nm to 35 nm. The geometric thickness of the antireflective layer in the middle layer modules is preferably 30 nm to 100 nm, particularly preferably 40 nm to 80 nm, especially 50 nm to 70 nm. The geometric thickness of the adapter layer is preferably 5 nm to 30 nm, particularly preferably 8 nm to 12 nm. The geometric thickness of the refractive index increasing layer is preferably 5 nm to 30 nm, particularly preferably 5 nm to 15 nm.

[0074] Since the individual layer modules can be formed independently of each other, combinations of the above embodiments are also possible, wherein the uppermost dielectric layer module is formed according to one embodiment and the lowermost dielectric layer module is formed according to another embodiment, and in the case of multiple silver layers, the intermediate layer modules are formed according to yet another embodiment. This results in the following preferred layer sequences (each starting from the substrate, i.e., the surface on which the functional coating is deposited): For a silver layer: - Lower anti-reflective layer – Silver layer – Upper anti-reflective layer - Lower anti-reflective layer – Silver layer – Upper adapter layer – Upper anti-reflective layer - Lower anti-reflective layer – Silver layer – Upper adapter layer – Upper refractive index increasing layer – Upper anti-reflective layer - Lower anti-reflective layer – Lower adapter layer – Silver layer – Upper anti-reflective layer - Lower anti-reflective layer – Lower adapter layer – Silver layer – Upper adapter layer – Upper anti-reflective layer - Lower anti-reflective layer – Lower adapter layer – Silver layer – Upper adapter layer – Upper refractive index increasing layer – Upper anti-reflective layer - Lower anti-reflective layer – Lower refractive index increasing layer – Lower adapter layer – Silver layer – Upper anti-reflective layer - Lower anti-reflective layer – Lower refractive index increasing layer – Lower adapter layer – Silver layer – Upper adapter layer – Upper anti-reflective layer - Lower anti-reflective layer – Lower refractive index increasing layer – Lower adapter layer – Silver layer – Upper adapter layer – Upper refractive index increasing layer – Upper anti-reflective layer For two silver layers, some possibilities are listed as examples: - Bottom anti-reflective layer – Silver layer – Middle anti-reflective layer – Silver layer – Top anti-reflective layer - Bottom anti-reflection layer – Bottom adapter layer – Silver layer – Middle adapter layer – Middle anti-reflection layer – Middle adapter layer – Silver layer – Top adapter layer – Top anti-reflection layer - Lower anti-reflective layer – Lower adapter layer – Silver layer – Middle adapter layer – Middle anti-reflective layer – Middle adapter layer – Silver layer – Upper adapter layer – Upper refractive index increasing layer – Upper anti-reflective layer - Lower anti-reflection layer – Lower refractive index increasing layer – Lower adapter layer – Silver layer – Middle adapter layer – Middle anti-reflection layer – Middle adapter layer – Silver layer – Upper adapter layer – Upper refractive index increasing layer – Upper anti-reflection layer - Lower anti-reflective layer – Lower refractive index increasing layer – Silver layer – Middle adapter layer – Middle anti-reflective layer – Silver layer – Upper adapter layer – Upper anti-reflective layer A similar structure is applicable to three silver layers, with one silver layer and another dielectric layer module added respectively.

[0075] In an advantageous embodiment of the invention, the functional coating includes at least one metallic barrier layer. This barrier layer may be disposed below and / or above the silver layers, and preferably in direct contact with the silver layers. The barrier layer is preferably disposed below and / or above each silver layer. The barrier layer is then positioned between the silver layers and the dielectric layer module. The barrier layer serves to protect the silver layers from oxidation, particularly when the coated glass plate is subjected to temperature treatments, such as those typically occurring in bending processes. The geometric thickness of the barrier layer is preferably less than 1 nm, for example, 0.1 nm to 0.5 nm. The barrier layer is preferably formed based on titanium or a nickel-chromium alloy.

[0076] The barrier layer negligibly alters the optical properties of the functional coating and is preferably present in all the embodiments described above. Particularly preferred is that the barrier layer is disposed directly above one / each of the silver layers, i.e., between the silver layer and the adjacent upper dielectric layer module, where it is particularly effective.

[0077] For the exemplary layer sequences listed above, the following preferred layer sequences are generated: For a silver layer: - Lower anti-reflective layer – Silver layer – Barrier layer – Upper anti-reflective layer - Lower anti-reflective layer – Silver layer – Barrier layer – Upper adapter layer – Upper anti-reflective layer - Lower anti-reflective layer – Silver layer – Barrier layer – Upper adapter layer – Upper refractive index increasing layer – Upper anti-reflective layer - Lower anti-reflective layer – Lower adapter layer – Silver layer – Barrier layer – Upper anti-reflective layer - Lower anti-reflective layer – Lower adapter layer – Silver layer – Barrier layer – Upper adapter layer – Upper anti-reflective layer - Lower anti-reflective layer – Lower adapter layer – Silver layer – Barrier layer – Upper adapter layer – Upper refractive index increasing layer – Upper anti-reflective layer - Lower anti-reflective layer – Lower refractive index increasing layer – Lower adapter layer – Silver layer – Barrier layer – Upper anti-reflective layer - Lower anti-reflective layer – Lower refractive index increasing layer – Lower adapter layer – Silver layer – Barrier layer – Upper adapter layer – Upper anti-reflective layer - Lower anti-reflective layer – Lower refractive index increasing layer – Lower adapter layer – Silver layer – Barrier layer – Upper adapter layer – Upper refractive index increasing layer – Upper anti-reflective layer For two silver layers, some possibilities are listed as examples: - Bottom anti-reflective layer – Silver layer – Barrier layer – Middle anti-reflective layer – Silver layer – Barrier layer – Top anti-reflective layer - Bottom Anti-reflective Layer – Bottom Adapter Layer – Silver Layer – Blocking Layer – Middle Adapter Layer – Middle Anti-reflective Layer – Middle Adapter Layer – Silver Layer – Blocking Layer – Top Adapter Layer – Top Anti-reflective Layer - Lower anti-reflective layer – Lower adapter layer – Silver layer – Barrier layer – Middle adapter layer – Middle anti-reflective layer – Middle adapter layer – Silver layer – Barrier layer – Upper adapter layer – Upper refractive index increasing layer – Upper anti-reflective layer - Lower anti-reflective layer – Lower refractive index increasing layer – Lower adapter layer – Silver layer – Barrier layer – Middle adapter layer – Middle anti-reflective layer – Middle adapter layer – Silver layer – Barrier layer – Upper adapter layer – Upper refractive index increasing layer – Upper anti-reflective layer - Lower anti-reflective layer – Lower refractive index increasing layer – Silver layer – Barrier layer – Intermediate adapter layer – Intermediate anti-reflective layer – Silver layer – Barrier layer – Upper adapter layer – Upper anti-reflective layer A similar structure is applicable to three silver layers, with one silver layer and another dielectric layer module added respectively.

[0078] In each case, the additional barrier layer may optionally be disposed directly below one / each of the silver layers, i.e., between the silver layer and the underlying dielectric layer module.

[0079] In another preferred embodiment, the functional coating is designed in the form of a multilayer polymer film. This multilayer polymer film does not contain a conductive layer. The multilayer polymer film preferably contains only polymer layers. The multilayer polymer film preferably contains 1 to 1000, particularly preferably 10 to 500, and even more preferably 50 to 100 polymer layers. This multilayer polymer film reflects infrared radiation while allowing visible light to pass through. Therefore, the TTS value of the windshield is reduced, while the TL value hardly decreases. Another advantage is that the film does not block electronic signals from sources such as mobile phones. The multilayer polymer film may contain polymer layers of different materials. The successive polymer layers of the multilayer polymer film preferably differ in their refractive index, so that IR radiation is reflected due to optical interference. Such films are commercially available, for example from 3M under the name UCSF (Ultra-Clear Solar Film). The multilayer polymer film is preferably provided on a polymer carrier film. The multilayer polymer film is preferably embedded in a thermoplastic interlayer.

[0080] In another preferred embodiment, the functional coating is designed as a coating made of nanoparticles. Here, the nanoparticles are applied directly to the surface of the glass plate. The functional coating preferably comprises cesium tungstate nanoparticles and / or indium oxide nanoparticles. Due to the use of a discontinuous nanoparticle layer, the mounting glass exhibits high transmittance for high frequencies in mobile phones, for example. Optical requirements for windshields, particularly in terms of transparency and tinting, can also be met. The nanoparticles are preferably embedded in a polymer matrix. Suitable mixtures are commercially available, for example, under the name DryWired® Liquid NanoTint®. The polymer matrix with nanoparticles is produced by curing directly onto the outer glass plate. This provides excellent adhesion. Alternatively, the nanoparticles are preferably embedded or applied in a polymer film and then integrated into the glass plate during lamination.

[0081] A projector is positioned on the inner space side of the windshield and illuminates the windshield above the inner space side surface of the inner glass panel. It is aligned with and illuminates the HUD area to produce a HUD projection. According to the invention, the projector's radiation is primarily p-polarized, i.e., has a p-polarized radiation component greater than 50%. The higher the p-polarized radiation component in the total radiation of the projector, the stronger the desired projected image and the weaker the intensity of undesirable reflections on the windshield surface. The p-polarized radiation component of the projector is preferably at least 70%, particularly preferably at least 80%, and especially at least 90%. In a particularly advantageous embodiment, the projector's radiation is essentially purely p-polarized—i.e., the p-polarized radiation component is 100% or only slightly deviated. The explanation of polarization direction here refers to the radiation incident plane on the windshield. p-polarized radiation refers to radiation whose electric field vibrates in the incident plane. s-polarized radiation refers to radiation whose electric field vibrates perpendicular to the incident plane. The incident plane is a vector space spanned by the incident vector and the surface normal of the windshield at the geometric center of the irradiated area.

[0082] The projector's radiation is preferably incident on the windshield at an angle of incidence of 45° to 70°, particularly 60° to 70°. In an advantageous embodiment, the angle of incidence deviates from the Brewster's angle by a maximum of 10°. The p-polarized radiation is then reflected only negligibly on the surface of the windshield, thus preventing ghosting. The angle of incidence is the angle between the incident vector of the projector's radiation and the surface normal on the inner space side of the HUD area's geometric center (i.e., the surface normal on the outer surface of the inner space side of the windshield). In the case of soda-lime glass, the Brewster's angle for the air-glass transition is 56.5°, which is commonly seen for window glass. Ideally, the angle of incidence should be as close to this Brewster's angle as possible. However, for example, an angle of incidence of 65°, common for HUD projection devices, can also be used, which is readily achievable in vehicles and deviates only slightly from the Brewster's angle, thus increasing the reflection of p-polarized radiation only negligibly.

[0083] Since the reflection of projector radiation occurs primarily on the reflective coating, rather than on the outer glass surface, it is unnecessary to arrange the outer glass surfaces at an angle to each other to avoid ghosting. Therefore, the outer surfaces of the windshield are preferably arranged substantially parallel to each other. The thermoplastic interlayer is therefore preferably not wedge-shaped, but rather has a substantially constant thickness, particularly in the vertical direction between the upper and lower edges of the windshield, as with the inner and outer glass panels. Conversely, a wedge-shaped interlayer has a variable, particularly increasing, thickness in the vertical direction between the upper and lower edges of the windshield. The interlayer is typically formed from at least one thermoplastic film. Because standard films are significantly more cost-effective than wedge films, the manufacture of this windshield becomes cheaper.

[0084] The outer and inner glass panes are preferably made of glass, particularly soda-lime glass, which is common for window glass. However, in principle, the glass panes can also be made of other types of glass (e.g., borosilicate glass, quartz glass, aluminosilicate glass) or transparent plastics (e.g., polymethyl methacrylate or polycarbonate). The thickness of the outer and inner glass panes can vary widely. Glass panes with a thickness of 0.8 mm to 5 mm are preferred, more preferably 1.4 mm to 2.5 mm, such as those with standard thicknesses of 1.6 mm or 2.1 mm.

[0085] The outer glass pane, inner glass pane, and thermoplastic interlayer can be transparent and colorless, but can also be tinted or colored. In a preferred embodiment, the total transmittance through the windshield (including the reflective coating and functional coating) is greater than 70%. The term total transmittance refers to the light transmittance of a motor vehicle glass pane as specified by the test method in ECE-R 43, Annex 3, § 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 required to be prestressed, this can be thermal or chemical prestressing.

[0086] In an advantageous embodiment, the outer glass pane is tinted or colored. This reduces the reflectivity of the outer surface of the windshield, making the glass pane more pleasing to the viewer. However, to ensure a preferred light transmittance (total transmittance) of at least 70% for the windshield, the light transmittance of the outer glass pane should preferably be at least 80%, particularly preferably at least 85%. Here, light transmittance describes the proportion of radiation transmitted at a 0° angle of incidence in the visible spectrum, within the spectral range of 380 nm to 780 nm. Light transmittance can be determined using commercially available measuring instruments, such as spectrometers from Perkin Elmer, by means of methods known to those skilled in the art. The inner glass pane and the interlayer are preferably transparent, i.e., untinted or uncolored. For example, green or blue tinted glass can be used as the outer glass pane.

[0087] Windshields are preferably curved in one or more directions in space, as is common for motor vehicle glass panels, where the typical radius of curvature is from about 10 cm to about 40 m. However, windshields can also be flat, for example, when intended for use as glass panels for buses, trains, or tractors.

[0088] The thermoplastic interlayer comprises at least one thermoplastic polymer, preferably ethylene vinyl acetate (EVA), polyvinyl butyral (PVB), or polyurethane (PU), or mixtures, copolymers, or derivatives thereof, with PVB being particularly preferred. The interlayer is typically formed from a thermoplastic film. The thickness of the interlayer is preferably from 0.2 mm to 2 mm, particularly preferably from 0.3 mm to 1 mm. The thermoplastic interlayer can consist of a single film or multiple separate films.

[0089] The windshield can be manufactured by methods known per se. The outer and inner glass panels are laminated together by an interlayer, for example by autoclave methods, vacuum bag methods, vacuum ring methods, calendering methods, vacuum laminators, or combinations thereof. The bonding of the outer and inner glass panels is typically carried out under the influence of heat, vacuum, and / or pressure.

[0090] The reflective coating and functional coating are preferably applied to the glass surface by physical vapor deposition (PVD), particularly preferably by cathodic sputtering (“sputtering”), and very particularly preferably by magnetic field-assisted cathodic sputtering (“magnetron sputtering”). This coating is preferably applied prior to lamination. Alternatively, in principle, the reflective coating and / or functional coating can also be provided on a carrier film, preferably made of polyethylene terephthalate (PET), disposed within a thermoplastic interlayer.

[0091] If the windshield is to be curved, the outer and inner glass panes are preferably subjected to a bending process before lamination and preferably after any possible coating process. Preferably, the outer and inner glass panes are bent together (i.e., simultaneously and using the same tool) in a consistent manner, as this ensures that the shapes of the glass panes optimally match each other for the subsequent lamination. Typical temperatures for the glass bending process are, for example, 500°C to 700°C. This temperature treatment also increases transparency and reduces the film resistance of the reflective coating.

[0092] The present invention further includes the use of the projection device according to the invention as a HUD in motor vehicles, particularly passenger cars or trucks.

[0093] The invention will now be explained in more detail with reference to the accompanying drawings and embodiments. The drawings are schematic and not to scale. The drawings are not intended to limit the invention in any way.

[0094] in: Figure 1 A plan view of the composite glass plate of a universal projection device is shown. Figure 2 A cross-section through a universal projection device is shown. Figure 3 A cross-section of a composite glass plate projected by the projection device according to the invention is shown. Figure 4 A cross-section of one embodiment of a windshield for a projection device according to the invention is shown. Figure 5a Figures 1 and 2 show cross-sections of one embodiment of a windshield used in a projection device according to the invention.

[0095] Figure 6 Transmission spectra of Examples 1, 3 and 4.

[0096] Figure 1 and Figure 2A detail of a general-purpose HUD projection device is shown. This projection device includes a windshield 10, specifically the windshield of a passenger vehicle. It also includes a projector 4, which is aimed at an area of ​​the composite glass panel 10. In this area, commonly referred to as HUD area B, an image can be generated by the projector 4, which is perceived by the viewer 5 (the driver of the vehicle) as a virtual image on the side of the composite glass panel 10 furthest from him when the viewer's eyes are within the so-called eye-tracking range E.

[0097] The windshield 10 is constructed of an outer glass panel 1 and an inner glass panel 2, which are connected to each other by a thermoplastic interlayer 3. Its lower edge U is arranged downward toward the engine of the passenger vehicle, and its upper edge O is arranged upward toward the roof of the vehicle. 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.

[0098] Figure 3 An embodiment of a windshield 10 formed according to the present invention is shown. The outer glass panel 1 has an outer side I facing the external environment in the installed position and an inner side II facing the interior space in the installed position. Similarly, the inner glass panel 2 has an outer side III facing the external environment in the installed position and an inner side IV facing the interior space in the installed position. The outer glass panel 1 and the inner glass panel 2 are, for example, made of soda-lime glass. The thickness of the outer glass panel 1 is, for example, 2.1 mm, and the thickness of the inner glass panel 2 is, for example, 1.6 mm or 2.1 mm. The intermediate layer 3 is, for example, formed of a PVB film with a thickness of 0.76 mm. This PVB film has a substantially constant thickness and, apart from the possible surface roughness common in the art, it is not formed as a so-called wedge film.

[0099] The outer surface III of the inner glass plate 2 has a reflective coating 20, which is provided as a reflective surface for projector radiation (and may additionally serve as an IR reflective coating).

[0100] The radiation from projector 4 is p-polarized, and in particular, essentially purely p-polarized. Since projector 4 illuminates the windshield 10 at an incident angle of approximately 65°, close to Brewster's angle, the radiation from the projector is only negligibly reflected on the outer surfaces I and IV of the composite glass panel 10. In contrast, the reflective coating 20 according to the invention is optimized for reflecting p-polarized radiation. It serves as a reflective surface for the radiation from projector 4, used to generate the HUD projection.

[0101] The functional coating 40 according to the invention is disposed on the inner side II of the outer glass plate 1. The functional coating 40 is optimized for the reflection of infrared (IR) radiation and is used to improve the thermal protection function of the windshield. The arrangement on the inner side II of the outer glass plate 1 ensures that the main part of the p-polarized radiation of the projector 4 has been reflected by the reflective coating 20 on the inner glass plate and can be used to generate HUD projection. Therefore, the interfering ghosting caused by the functional coating 40 is largely avoided.

[0102] Figure 5a and 5b The image shows one cross-section through the windshield with a polymer carrier film. Figure 5a A windshield with a reflective coating 20 according to the invention on the outer side of the inner glass panel 2 is shown. The reflective coating 20 is applied directly to the inner glass panel 2 using a PVD process, in this case by magnetron sputtering. A functional coating 40 is disposed on a polymer carrier film 50 made of PET and embedded in a thermoplastic interlayer 3 consisting of two layers of PVB sheets. Since the reflective coating 20 is disposed directly on the inner glass panel 2, no carrier film or thermoplastic interlayer interferes with the generation of the HUD image.

[0103] exist Figure 5b In the illustrated embodiment, the functional coating 40 and the reflective coating 20 are arranged on a single carrier film 50. Therefore, only one additional carrier film needs to be inserted during the lamination process, which is advantageous in terms of process technology. The distance between the reflective coating 20 and the functional coating 40 is defined solely by the carrier film 50. This effectively avoids intrusive ghosting images caused by the functional coating 40, as any possible reflections on the functional coating overlap with the reflections on the reflective coating and become a single image. Therefore, any possible reflections on the functional coating will not be perceived as intrusive ghosting when generating the HUD image.

[0104] Figure 4 A layer sequence of one embodiment of a windshield 10 according to the present invention is shown. According to the invention, a reflective coating 20 is arranged in a thin-layer stack on the outer side of the inner glass panel 2. The reflective coating 20 includes a silver-based conductive layer 21. A metal barrier layer 24 is disposed directly above the conductive layer 21. An upper dielectric layer structure 23 is disposed above it. A lower dielectric layer structure 22 is disposed below the conductive layer 21.

[0105] According to the present invention, the functional coating 40 is arranged on the inner side of the outer glass plate 1 in the form of a thin-layer stack. The functional coating 40 includes a silver-based conductive layer 41. A metal barrier layer 44 is disposed directly above the conductive layer 41. An uppermost dielectric layer module 43 is disposed above it. A lowermost dielectric layer module 42 is disposed below the conductive layer 41.

[0106] The inner glass plate 2 and the outer glass plate 1 are connected by a thermoplastic interlayer 3.

[0107] The layer thicknesses shown are not drawn to scale. Therefore, for example, the thicknesses of glass plates 1 and 2 and the thermoplastic intermediate layer 3 appear too small compared to the thin layers. Furthermore, the structures shown are intended to be illustrative only. Therefore, barrier layers may or may not be present and may be arranged above and / or below the conductive layers. The dielectric layer structures and layer modules may each comprise a single dielectric layer or multiple layers, provided that at least one dielectric layer is present above and below the conductive layers 21 and 41. Exemplary materials and layer thicknesses can be learned from the following embodiments.

[0108] Tables 1 and 2 show the layer sequence of a windshield 10 having a reflective coating 20 on the outer side of the inner glass plate and a functional coating 40 on the inner side of the outer glass plate according to embodiments 1 to 6 of the present invention, as well as the material and geometric layer thickness of each layer. The dielectric layers can be doped independently of each other, for example with boron or aluminum.

[0109] Table 3 summarizes the optical thicknesses and ratios of the upper and lower layer structures. The ratio φ describes the ratio of the optical thickness of the upper dielectric layer structure 23 to the optical thickness of the lower dielectric layer structure 22.

[0110] The optical thicknesses were obtained by multiplying the geometric thicknesses and refractive indices (SiN: 2.0; SiZrN: 2.2, ZnO: 2.0) as shown in Tables 1 and 2, respectively.

[0111] Table 3 Optical thickness of the upper dielectric layer structure Optical thickness of the lower dielectric layer structure ratio Example 1 122 74 1.65 Example 2 102 60 1.70 Example 3 102 60 1.70 Example 4 102 60 1.70 Example 5 102 60 1.70 Example 6 102 60 1.70 Comparative Example 122 74 1.65

[0112] Table 4 summarizes the optical thicknesses and ratios of the top and bottom layer modules. The ratio γ describes the ratio of the optical thickness of the top dielectric layer module 43 to the optical thickness of the bottom dielectric layer module 42.

[0113] Table 4 Optical thickness of the top dielectric layer module Optical thickness of the bottom dielectric layer module ratio γ Example 1 92 82 1.12 Example 2 92 92 1.00 Example 3 82 92 0.89 Example 4 92 92 1.00 Example 5 122 102 0.84 Example 6 82 132 1.61 Comparative Example 0 0 0

[0114] Table 5 summarizes the optical thicknesses and ratios of the top, middle, and bottom layer modules. Ratio η1 describes the ratio of the optical thickness of the middle dielectric layer module to that of the top dielectric layer module. Ratio η2 describes the ratio of the optical thickness of the middle dielectric layer module to that of the bottom dielectric layer module 42.

[0115] Table 5 Optical thickness of the top dielectric layer module Optical thickness of the bottom dielectric layer module Optical thickness of intermediate dielectric layer module Ratio η1 ratio η2 Example 3 82 92 180 1.96 1.96 Example 4 Lower Module 92 92 180 2.20 1.96

[0116] Table 6 presents the transmittance values ​​according to light type A. Furthermore, the thermal comfort values ​​are given in the form of TTS values. This reflects the total amount of solar energy received and is measured according to ISO 13837.

[0117] Table 6 Transmittance TL A / % TTS / % Example 1 71 54.0 Example 2 71 52.3 Example 3 72 51.5 Example 4 71 49.1 Example 5 70 53.0 Example 6 69 52.8 Comparative Example 76 61.3

[0118] The comparative examples listed in Table 2 differ from the embodiments in that the windshields lack a functional coating. Due to the reflective coating on the inner glass panel, the windshields exhibit good reflective properties for HUD imaging. However, as indicated by the high TTS value, the glass panels of the comparative examples have poor thermal insulation properties. Compared to the comparative examples, Examples 1 and 3 show significantly reduced TTS values ​​and therefore improved thermal protection. Due to the reflective coating according to the invention for reflecting p-polarized radiation, the windshields according to the invention are excellently suited for HUD projection devices.

[0119] Examples 1 to 6 are all suitable as projection surfaces for HUD imaging with p-polarized radiation. Because of the design scheme according to the present invention, which has a thinner silver layer in the functional coating than in the reflective coating, there is no interfering ghosting caused by reflection on the conductive layer of the functional coating.

[0120] All embodiments 1 to 6 have a ratio φ of at least 1.6. This ensures a color-neutral display of the HUD projection.

[0121] The main difference between Examples 5 and 6 and Examples 1 and 2 lies in the ratio γ of the optical thickness of the uppermost dielectric layer module to the optical thickness of the lowermost dielectric layer module. The values ​​for Examples 1 and 2 are between 0.9 and 1.1, while the values ​​for Examples 5 and 6 are below or above this range. For Examples 1 and 2, this surprisingly results in an improved transmittance value of 71.

[0122] Figure 6 Three transmission spectra of Examples 1, 3, and 4 are shown, and their structures are listed in Table 1. These spectra were recorded under the same conditions and can therefore be directly compared. It can be seen that all Examples 1, 3, and 4 have very similar transmittance in the visible (VIS) spectral range (400 nm to 800 nm). As listed in Table 6, all Examples 1, 3, and 4 have a TL value of at least 70% according to light type A. Therefore, they are well-suited as windshields or front side windows in the automotive field.

[0123] The assembled glass according to Example 4 exhibits the best thermal protection performance, as evidenced by low TTS values ​​(Table 6) and low transmittance in the infrared (IR) range (800nm-2500nm).

[0124] For comparison Figure 6The spectrum indicates that the TL value decreases with increasing number of silver layers in the functional coating. Nevertheless, due to the structure according to the invention, high transmittance in the visible spectrum can still be achieved, making it suitable for use as a windshield. Table 5 shows the values ​​of ratios η2 and η2, which give the ratio of the optical thickness of the intermediate dielectric layer module to the optical thickness of the uppermost and lowermost dielectric layer modules. Here, the optical thickness of the intermediate dielectric layer module is significantly larger than that of the lowermost or uppermost layer module. Surprisingly, it has been shown that this ratio results in a relatively high TL value despite the layer stack of the functional coating comprising multiple silver layers.

[0125] List of reference numerals in the attached diagram: 1. Outer glass panel 2. Inner glass plate 3. Thermoplastic interlayer 4. Projector 5. Viewers / Vehicle Drivers 10 Windshield 20 Reflective coating 21. Silver-based conductive layer in reflective coating 22. Structure of the lower dielectric layer in the reflective coating 23. Upper dielectric layer structure in reflective coating 24 Barrier Layers 40 Functional Coating 41. Silver-based conductive layer in functional coatings 42 Bottom dielectric layer module 43 Top Dielectric Layer Module 44 Metal Barrier Layer 50 Polymer carrier membrane O Windshield 10 upper edge U-shaped lower edge of the windshield 10 B. HUD area on windshield 10 E Eye movement range I. The outer surface of the outer glass plate 1 away from the intermediate layer 3, the outer side of the outer glass plate 1 II. The inner surface of the outer glass panel 1 facing the inner space of the intermediate layer 3, and the inner side of the outer glass panel 1. III. The outer surface of the inner glass plate 2 facing the intermediate layer 3, the outer side of the inner glass plate 2 IV. The inner surface of the inner glass plate 2 away from the intermediate layer 3, the inner side of the inner glass plate 2.

Claims

1. A projection device for a head-up display (HUD), comprising at least: - A windshield (10) comprising an outer glass panel (1) and an inner glass panel (2) connected to each other by a thermoplastic interlayer (3), having a HUD area (B); and - Projector (4), which is aligned with the HUD area (B); wherein the radiation from the projector (4) is primarily p-polarized; and - A reflective coating (20) suitable for reflecting p-polarized radiation, wherein - The reflective coating (20) contains exactly one silver-based conductive layer (21). - The reflective coating (20) includes a lower dielectric layer structure (22) below the conductive layer (21), which has a refractive index of at least 1.

9. - The reflective coating (20) includes an upper dielectric layer structure (23) above the conductive layer (21), having a refractive index of at least 1.9; and - Functional coating (40) suitable for reflecting IR radiation, wherein - A functional coating (40) and a reflective coating (20) are disposed between the inner glass plate (2) and the outer glass plate (1), wherein the reflective coating (20) is disposed between the inner glass plate (2) and the functional coating (40). The functional coating (40) comprises at least one silver-based conductive layer (41). The functional coating includes a lowermost dielectric layer module (42) below the silver-based conductive layer (41), having a refractive index of at least 1.

9. The functional coating (40) includes an uppermost dielectric layer module (43) above the silver-based conductive layer (41), having a refractive index of at least 1.9, and In the functional coating (40), the ratio of the optical thickness of the uppermost dielectric layer module (43) to the optical thickness of the lowermost dielectric layer module (42) is 0.9 to 1.

2. i) wherein the reflective coating (20) is disposed on the outer side (III) of the inner glass plate (2) facing the thermoplastic intermediate layer (3), and wherein the functional coating (40) is disposed on the inner side (II) of the outer glass plate (1) facing the thermoplastic intermediate layer (3), or ii) Wherein a functional coating (40) or a reflective coating (20) is disposed on a polymer carrier film (50), the polymer carrier film (50) being embedded in a thermoplastic interlayer (3), or iii) Wherein the functional coating (40) and the reflective coating (20) are arranged on a single polymer carrier film (50), wherein the polymer carrier film (50) is embedded in a thermoplastic intermediate layer (3).

2. The projection device according to claim 1, wherein in the reflective coating (20), the ratio of the optical thickness of the upper dielectric layer structure (23) to the optical thickness of the lower dielectric layer structure (22) is at least 1.

6.

3. The projection device according to claim 1 or 2, wherein the geometric thickness of at least one silver-based conductive layer (41) included in the functional coating (40) is less than the geometric thickness of the silver-based conductive layer (21) in the reflective coating.

4. The projection device according to claim 1 or 2, wherein in the functional coating (40), the ratio of the optical thickness of the uppermost dielectric layer module (43) to the optical thickness of the lowermost dielectric layer module (42) is 1.

0.

5. The projection device according to claim 1 or 2, wherein the functional coating (40) comprises two silver-based conductive layers (41) and an intermediate dielectric layer module therebetween, wherein the geometric thickness of all the silver-based conductive layers (41) in the functional coating (40) is less than the geometric thickness of the silver-based conductive layers (21) in the reflective coating (20).

6. The projection device according to claim 5, wherein in the functional coating (40), the ratio of the optical thickness of the intermediate dielectric layer module to the optical thickness of the bottom dielectric layer module (42) and the optical thickness of the top dielectric layer module is greater than 1.

9.

7. The projection device according to claim 1 or 2, wherein the reflective coating (20) is applied on the outer side (III) of the inner glass plate (2) facing the thermoplastic intermediate layer (3) by physical vapor deposition.

8. The projection device according to claim 1 or 2, wherein the functional coating (40) is applied on the inner side (II) of the outer glass plate (1) facing the thermoplastic intermediate layer (3) by physical vapor deposition.

9. The projection device according to claim 1 or 2, wherein in the reflective coating (20) - The lower dielectric layer structure (22) includes a first lower dielectric layer and a second lower dielectric layer with a refractive index of at least 1.9, and / or - The upper dielectric layer structure (23) includes a first upper dielectric layer and a second upper dielectric layer with a refractive index of at least 1.

9.

10. The projection device according to claim 1 or 2, wherein the reflective coating (20) and the functional coating (40) each comprise at least one metal barrier layer (24) disposed above and / or below at least one conductive layer (21, 41) and have a geometric thickness of less than 1 nm.

11. The projection device according to claim 1 or 2, wherein all dielectric layers of the reflective coating (20) have a refractive index of at least 1.

9.

12. The projection device according to claim 1 or 2, wherein in the reflective coating (20), the conductive layer (21) has a geometric thickness of 10 nm to 14 nm.

13. The projection device according to claim 1 or 2, wherein the functional coating (40) is connected to a voltage source via a busbar and can be heated by applying a voltage.

14. The projection device according to claim 1 or 2, wherein the functional coating (40) is designed as a multilayer polymer film without a conductive layer.

15. The projection device according to claim 1 or 2, wherein the radiation from the projector (4) is purely p-polarized and is incident on the windshield (10) at an angle of incidence of 60° to 70°.

16. The projection device according to claim 1 or 2, wherein in the reflective coating (20), the ratio of the optical thickness of the upper dielectric layer structure (23) to the optical thickness of the lower dielectric layer structure (22) is at least 1.

7.

17. The projection device according to claim 1 or 2, wherein in the reflective coating (20), the ratio of the optical thickness of the upper dielectric layer structure (23) to the optical thickness of the lower dielectric layer structure (22) is at least 1.

8.

18. The projection device according to claim 5, wherein in the functional coating (40), the ratio of the optical thickness of the intermediate dielectric layer module to the optical thickness of the bottom dielectric layer module (42) and the optical thickness of the top dielectric layer module is greater than 2.

0.

19. The projection device according to claim 5, wherein in the functional coating (40), the ratio of the optical thickness of the intermediate dielectric layer module to the optical thickness of the bottom dielectric layer module (42) and the optical thickness of the top dielectric layer module is greater than 2.

1.

20. The projection device according to claim 9, wherein in the reflective coating (20) - The lower dielectric layer structure (22) includes a first lower dielectric layer based on silicon nitride and a second lower dielectric layer based on zinc oxide, and / or - The upper dielectric layer structure (23) includes a first upper dielectric layer based on silicon nitride and a second upper dielectric layer based on zinc oxide.

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