Composite panel for a head-up display

Description

[0001] The invention relates to a composite pane for a head-up display and a projection arrangement for a head-up display.

[0002] Vehicles, especially passenger cars, are increasingly being equipped with so-called head-up displays (HUDs). A head-up display (HUD) is a display system that projects additional information in the form of images into the driver's field of vision.

[0003] The head-up display consists of a projector (imaging unit) and several optical modules for redirecting or reflecting an image onto a projection or reflection surface. Typically, a composite pane of glass, particularly the vehicle's windshield, serves as the projection surface. Although the image is projected onto the windshield, the driver's human eye perceives it as hovering distantly above the vehicle's hood.

[0004] In this way, additional information can be projected into the driver's field of vision, such as the current driving speed and navigation or warning information, which the driver can perceive without having to change their direction of vision. Head-up displays can thus significantly contribute to improving road safety.

[0005] Typically, the image generated by the projector consists of polarized, particularly S-polarized, light radiation. The S-polarized light hits the laminated glass at a specific angle of incidence and is at least partially refracted into the laminated glass and reflected as S-polarized light into the driver's field of vision. However, the reflected images are not colorfast or display unwanted reflections, so-called double images.

[0006] The angle of incidence of the S-polarized radiation is typically about 65%, which roughly corresponds to the Brewster angle for an air-to-glass transition (57.2° for soda-lime glass). This creates the problem that the projector image is reflected at both outer transitions from air to glass and from glass to air. This results in a slightly offset secondary image, the so-called "ghost image," appearing alongside the desired main image. This problem is mitigated by arranging the windshield surfaces at an angle to each other. This is achieved by using a wedge-shaped interlayer during the lamination of the windshield, which is designed as a composite pane. This allows for an overlay of the main image and the ghost image.

[0007] Wedge films are expensive, making the production of such a composite panel for a HUD quite costly. Therefore, there is a need for HUD systems that operate on windshields without wedge films. For example, it is possible to operate the HUD projector with P-polarized radiation, which is not significantly reflected by the windshield surfaces due to the irradiation angle close to the Brewster angle. Instead, the windshield has a reflective coating as a reflection surface for the P-polarized radiation.

[0008] DE 10 2014 220189 A1 discloses a HUD projection system with P-polarized radiation and a metallic layer as a reflective structure. WO 2019 / 046157 A1 also discloses a HUD system with P-polarized radiation. A reflective coating with at least two metallic layers is used.

[0009] CN 106 646 874 A discloses a composite pane for a HUD. The composite pane has a nano-coating that reflects P-polarized light.

[0010] WO 2020 / 94422 A1 discloses a composite pane for a HUD system. The composite pane has an electrically conductive coating on a surface of the outer pane or the inner pane facing the intermediate layer, or within the intermediate layer, wherein the radiation of the HUD projector is P-polarized.

[0011] Glazing such as that used in windshields, panoramic roofs, and sunroofs is known to require specific sun protection. A measure of the total transmitted thermal radiation through the pane is described by the so-called TTS value. The TTS value can be measured, for example, according to ISO 13837. With high light transmission, too much thermal radiation is transmitted through the glazing. With very low light transmission, the glazing is too dark overall, making it impossible for the person behind the glazing to see through.

[0012] The object of the present invention is to provide a composite pane for a head-up display which has good reflectivity for P-polarized radiation in the visible spectral range and improves the TTS value.

[0013] The object of the present invention is achieved by a composite pane according to claim 1. Preferred embodiments are evident from the subclaims.

[0014] The composite pane for a head-up display (HUD) according to the invention comprises a first pane and a second pane, which are bonded together via a thermoplastic intermediate layer. The first pane has a first surface (I) and a second surface (II). The second pane also has a first surface (III) and a second surface (IV). Furthermore, the composite pane has a HUD region and a first coating suitable for reflecting P-polarized radiation. The first coating comprises precisely one electrically conductive silver-based layer.

[0015] The laminated pane is designed to separate the interior from the exterior environment in a window opening of a vehicle. The laminated pane is preferably the windshield of a motor vehicle, in particular a passenger car or truck.

[0016] As is common with HUDs, a projector illuminates an area of ​​the windshield, where the radiation is reflected toward the viewer (driver), creating a virtual image that the viewer perceives from behind the windshield. The area of ​​the windshield illuminated by the projector is called the HUD area. The projector's beam direction can be varied using optical elements (e.g., mirrors), particularly vertically, to adapt the projection to the viewer's height.

[0017] P-polarized radiation is used to generate a HUD image. The composite pane has a first coating suitable for reflecting P-polarized radiation, comprising an electrically conductive silver-based layer.

[0018] Since the angle of incidence of approximately 65° typical for HUD projection systems is relatively close to the Brewster angle for an air-to-glass interface (57.2°, soda-lime glass), P-polarized radiation is barely reflected from window surfaces, while S-polarized radiation is reflected significantly more strongly. The reflection of P-polarized radiation occurs primarily at the first coating.

[0019] A second coating is provided to reduce the transmission of total thermal radiation. This minimizes the heating inside rooms or vehicles and reduces the energy required to create a comfortable ambient climate for the occupants.

[0020] In other words, the invention provides that the composite pane has a first coating for reflecting P-polarized radiation and a second coating for reducing the total transmitted thermal radiation through the composite pane. Surprisingly, it has been shown that such a composite pane according to the invention has significantly improved TTS values ​​(ISO 13837) compared to previously known composite panes. With a transmission in the visible range > 70%, the TTS value can be reduced by up to 5% in this way without negatively affecting the optical reflection properties of the composite pane.

[0021] According to the invention, the first reflective coating is arranged on a surface (III, IV) of the second pane, and the second coating is arranged on a surface (I, II) of the first pane. The first and second coatings are preferably applied to a surface of the two panes facing the intermediate layer, with the first coating being arranged on the first surface (III) of the second pane and the second coating being arranged on the second surface (II) of the first pane.

[0022] The second coating preferably has a plurality of purely dielectric layers, comprising at least a first dielectric layer or layer sequence whose refractive index is greater than 1.9 and a second purely dielectric layer or layer sequence whose refractive index is less than 1.6. Particularly preferably, a third purely dielectric layer or layer sequence can be provided whose refractive index is greater than 1.9, and the second purely dielectric layer or layer sequence is arranged between the first purely dielectric layer or layer sequence and the third purely dielectric layer or layer sequence. The layers or layer sequences can be constructed alternately on top of one another.The first and second purely dielectric layer or layer sequence preferably contains silicon nitride Si 3 N 4 , tin oxide SnO 2 , zinc oxide ZnO, titanium dioxide TiO 2 , zirconium dioxide ZrO 2 , hafnium oxide HfO 2 , vanadium oxide V 2 O 5 , niobium oxide Nb 2 O 5 , tantalum oxide Ta 2 O 5 , tungsten oxide WO 3 . The second purely dielectric layer or layer sequence preferably contains silicon dioxide SiO 2 , calcium fluoride CaF 2 , magnesium fluoride MgF 2 or a nanoporous layer.

[0023] The second purely dielectric layer or layer sequence exhibits high mechanical and chemical stability and is less sensitive to water or organic contaminants. Its production is associated with significantly lower costs. The anti-reflective effect is determined on the one hand by the refractive index and on the other hand by the thickness of the second purely dielectric layer or layer sequence. In the case of the nanoporous layer, the refractive index depends on the pore size and the density of the pores. In a preferred embodiment, the pores are sized and distributed such that the refractive index is from 1.2 to 1.4, particularly preferably from 1.25 to 1.35. The thickness of the second purely dielectric layer or layer sequence is preferably from 30 nm to 500 nm, particularly preferably from 50 nm to 150 nm.

[0024] The first coating is a thin-film stack. The thin-film stack consists of a sequence of thin individual layers. This thin-film stack contains precisely one electrically conductive silver-based layer. The electrically conductive silver-based layer imparts the basic reflective properties to the first coating, as well as an IR-reflecting effect and electrical conductivity. The electrically conductive silver-based layer can also be simply referred to as a silver layer.

[0025] The electrically conductive layer preferably contains at least 90 wt.% silver, more preferably at least 99 wt.% silver, most preferably at least 99.9 wt.% silver. The silver layer can contain dopants, for example palladium, gold, copper or aluminum. The geometric layer thickness of the silver layer is preferably at most 15 nm [nanometers], more preferably at most 14 nm, most preferably 10 nm. This makes it possible to achieve advantageous reflectivity in the IR range without excessively reducing the transmission in the visible range. The geometric layer thickness of the silver layer is preferably at least 7 nm, more preferably at least 8 nm. The geometric layer thickness of the silver layer is particularly preferably 10 nm to 14 nm.

[0026] In an advantageous embodiment, the first coating does not comprise any dielectric layers with a refractive index of less than 1.9. All dielectric layers of the reflective coating thus have a refractive index of at least 1.9. A particular advantage of the present invention is that the desired reflective properties can be achieved solely with relatively high-index dielectric layers. Since silicon oxide layers, which have low deposition rates during magnetic-field-assisted cathode deposition, are particularly suitable for low-index layers with a refractive index of less than 1.9, the first coating can be produced quickly and cost-effectively.

[0027] The first coating contains, independently of one another, a dielectric layer or a dielectric layer sequence with a refractive index of at least 1.9 above and below the silver layer. The dielectric layers can be based, for example, 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. These oxides and nitrides can be deposited stoichiometrically, substoichiometrically, or superstoichiometrically. They can contain dopants, for example, aluminum, zirconium, titanium, or boron.

[0028] The optical thickness of the upper dielectric layer or layer sequence of the first coating is preferably from 50 nm to 200 nm, particularly preferably from 130 nm to 170 nm. The optical thickness of the lower dielectric layer or layer sequence is preferably from 30 nm to 100 nm, particularly preferably from 35 nm to 90 nm. This achieves good results.

[0029] In principle, it is sufficient if the HUD area of ​​the composite pane, especially a windshield, is coated with the first and second coatings. However, additional areas can also be coated with the first and second coatings. The composite pane can be coated with the first and second coatings essentially over its entire surface, which may be preferred for manufacturing reasons.

[0030] In one embodiment of the invention, at least 80% of the windshield surface is provided with the first and second coatings. In particular, the first and second coatings are applied over the entire surface of the windshield, with the exception of a peripheral edge region and optionally a local area that serves as communication, sensor, or camera windows to ensure the transmission of electromagnetic radiation through the windshield and is therefore not provided with the first coating. The peripheral uncoated edge region has a width of up to 20 cm, for example. It prevents direct contact of the first coating with the surrounding atmosphere, so that the first coating inside the windshield is protected from corrosion and damage.

[0031] The composite pane according to the invention provides high reflectivity to P-polarized radiation in the spectral range from 450 nm to 650 nm (nanometers), which is relevant for HUD displays. HUD projectors typically operate at wavelengths of 473 nm, 550 nm, and 630 nm (RGB). This results in a high-intensity HUD image.

[0032] The projector is arranged on the interior side of the composite pane and illuminates the composite pane via an interior-side surface of the second pane. For the purposes of the invention, the "outside surface" refers to the main surface intended to face the exterior environment in the installed position. For the purposes of the invention, the "inside surface" refers to the main surface intended to face the interior in the installed position.

[0033] The projector is directed at the HUD area and irradiates it to generate the HUD projection. According to the invention, the projector's radiation is predominantly P-polarized, i.e., it has a P-polarized radiation component of greater than 50%. The higher the proportion of P-polarized radiation in the total radiation of the projector, the more intense the desired projection image and the less intense the unwanted reflection on the surface (IV) of the interior-side second pane of the composite pane. The P-polarized radiation component of the projector is preferably at least 70%, more preferably at least 80%, and especially preferably at least 90%. In a particularly advantageous embodiment, the projector's radiation is essentially purely P-polarized—the P-polarized radiation component is therefore 100% or deviates only insignificantly therefrom.The polarization direction refers to the plane of incidence of the radiation on the laminated glass, especially the windshield. P-polarized radiation refers to radiation whose electric field oscillates in the plane of incidence. S-polarized radiation refers to radiation whose electric field oscillates perpendicular to the plane of incidence. The plane of incidence is defined by the incidence vector and the surface normal of the windshield at the geometric center of the irradiated area.

[0034] The projector's radiation preferably hits the windshield at an angle of incidence of 45° to 75°, particularly 60° to 70°. In an advantageous embodiment, the angle of incidence deviates from the Brewster angle by no more than 10°. The P-polarized radiation is then reflected only insignificantly by the surfaces of the interior pane, so that no ghost image is created. The angle of incidence is the angle between the incidence vector of the projector radiation and the interior-side surface normal (i.e., the surface normal to the interior-side external surface of the windshield) in the geometric center of the HUD area. The Brewster angle for an air-glass transition in the case of soda-lime glass, which is commonly used for window panes, is 57.2°. Ideally, the angle of incidence should be as close to this Brewster angle as possible.However, angles of incidence of 65°, for example, can also be used, which are common for HUD projection arrangements, can be easily implemented in vehicles and deviate only slightly from the Brewster angle, so that the reflection of the P-polarized radiation increases only insignificantly.

[0035] Since the reflection of the projector radiation occurs essentially at the first coating and not at the external pane surfaces, it is not necessary to arrange the external pane surfaces at an angle to one another in order to avoid ghosting. The external surfaces of the composite pane are therefore preferably arranged essentially parallel to one another. For this purpose, the thermoplastic intermediate layer is preferably not wedge-shaped, but has an essentially constant thickness, in particular in the vertical section between the upper edge and the lower edge of the windshield, just like the inner pane and the outer pane. A wedge-shaped intermediate layer, on the other hand, would have a variable, in particular increasing, thickness in the vertical section between the lower edge and the upper edge of the windshield. The intermediate layer is typically formed from at least one thermoplastic film.Since standard films are significantly cheaper than wedge films, the production of the windshield is made more cost-effective.

[0036] The first pane and the second pane are preferably made of glass, in particular soda-lime glass, which is common for window panes. However, the 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 first pane as the outer pane and the second pane as the inner pane can vary widely. Preferably, panes with a thickness in the range of 0.8 mm to 5 mm, more preferably 1.1 mm to 2.5 mm, are used, for example, those with the standard thicknesses of 1.6 mm or 2.1 mm.

[0037] The second pane and the thermoplastic interlayer can be clear and colorless, but also tinted or colored. The total transmission through the windshield (including the reflective coating) is greater than 70% in a preferred embodiment. The term "total transmission" refers to the method for testing the light transmittance of motor vehicle windows specified in ECE-R 43, Annex 3, Section 9.1. The first pane and the second pane can independently be untempered, partially tempered, or toughened. If at least one of the panes is to be tempered, this can be thermally or chemically toughened.

[0038] According to the invention, the first pane is tinted or colored. This reduces the exterior reflectivity of the laminated pane, making the pane more pleasant to an outside observer. However, to ensure the prescribed light transmission of 70% for windshields (total transmission), the outer pane (here, the first pane) should preferably have a light transmission of at least 80%, particularly preferably at least 85%. The second pane and the intermediate layer are preferably clear, i.e., not tinted or colored. For example, green or blue-tinted glass can be used as the outer pane.

[0039] The composite pane is preferably curved in one or more directions, as is common for automotive windows, with typical radii of curvature ranging from approximately 10 cm to approximately 40 m. However, the composite pane can also be flat, for example, if it is intended for use as a pane for buses, trains, or tractors.

[0040] The thermoplastic intermediate layer contains at least one thermoplastic polymer, preferably ethylene-vinyl acetate (EVA), polyvinyl butyral (PVB), or polyurethane (PU), or mixtures or copolymers or derivatives thereof, particularly preferably PVB. The intermediate layer is typically formed from a thermoplastic film. The thickness of the intermediate layer is preferably from 0.2 mm to 2 mm, particularly preferably from 0.3 mm to 1 mm.

[0041] The composite pane can be manufactured using conventional methods. The first pane and the second pane are laminated together via the intermediate layer, for example, using autoclave processes, vacuum bag processes, vacuum ring processes, calender processes, vacuum laminators, or combinations thereof. The bonding of the outer pane and inner pane is typically achieved using heat, vacuum, and / or pressure.

[0042] The first coating is preferably applied to a wafer surface by physical vapor deposition (PVD), particularly preferably by cathode sputtering, and most preferably by magnetic field-assisted cathode sputtering. The second coating is preferably deposited by PVD or a wet chemical deposition process. The coatings are preferably applied prior to lamination.

[0043] The invention also includes a projection arrangement for a head-up display, wherein the projection arrangement comprises the composite pane according to the invention and a projector, wherein the projector is directed onto the HUD area of ​​the composite pane and the radiation of the projector is predominantly P-polarized.

[0044] The invention is explained in more detail below with reference to figures and exemplary embodiments. The figures are schematic representations and not to scale. The figures do not limit the invention in any way.

[0045] They show: Figure 1 is a plan view of a composite pane of a generic projection arrangement, Figure 2 is a cross-section through the composite pane, Figure 3 is a cross-section through a first embodiment of a composite pane according to the invention, Figure 3 is a cross-section through an alternative design variant which does not correspond to the present invention, Figure 4 is a cross-section through an embodiment of a first coating and a second coating, and Figure 5 is a reflection spectrum of a composite pane according to the invention with P-polarized radiation.

[0046] Numerical values ​​are generally not to be understood as exact values, but also include a tolerance of + / - 1% to + / - 10%.

[0047] Figure 1 shows schematically a composite pane 10. Figure 2shows a schematic of a generic projection arrangement for a HUD. The projection arrangement comprises a composite pane 10 designed as the windshield of a passenger car. Furthermore, the projection arrangement has a projector 4 directed onto an area of ​​the composite pane 10. This area is usually referred to as the HUD area B. Images generated by the projector 4 can be projected into this area. These images are perceived by a viewer 5 (e.g., a vehicle driver) as virtual images on the side of the composite pane 10 facing away from them if their eyes are located within the so-called eyebox E.

[0048] The composite pane 10 is constructed from a first pane 1 as the outer pane and a second pane 2 as the inner pane of the passenger car, which are connected to each other via a thermoplastic intermediate layer 3. Its lower edge U is positioned downwards toward the engine of the passenger car, while its upper edge O is positioned upwards toward the roof. In the installed position, the first pane 1 faces the outside environment, while the second pane 2 faces the vehicle interior.

[0049] Figure 3A shows schematically a first embodiment of the composite pane 10 in cross section.

[0050] The first pane 1 has an outer surface I, which, in the installed position, faces the outside environment, and an inner surface II, which, in the installed position, faces the interior. Furthermore, the composite pane 1 comprises the second pane 2, which has an outer surface III and an inner surface IV. Surface III faces the outside environment in the installed position. In contrast, surface IV faces the outside environment in the installed position.

[0051] The first pane 1 has a thickness of 2.1 mm, for example, and the second pane 2 has a thickness of 1.6 mm or 2.1 mm. The intermediate layer 3 is formed, for example, from a PVB film with a thickness of 0.76 mm. The PVB film has a substantially constant thickness, except for any surface roughness typical of the industry.

[0052] The inner surface II of the first pane 1 is provided with a second coating 30 according to the invention, which is intended to reduce the TTS value. The outer surface III of the second pane 2 is provided with a first coating 20 according to the invention, which is intended as a reflection surface for the projector radiation (and possibly additionally as an IR-reflecting coating).

[0053] The radiation from projector 4 is essentially P-polarized. Since projector 4 irradiates the composite pane 10 at an angle of incidence of approximately 65°, which is close to the so-called Brewster angle, the projector's radiation is only insignificantly reflected by the external surfaces I, IV of the composite pane 10. The first coating 20, on the other hand, is optimized for the reflection of P-polarized radiation. It serves as a reflection surface for the radiation from projector 4 to generate the HUD projection.

[0054] Figure 3Bshows schematically an alternative embodiment of the composite pane 10, which, however, is not part of the present invention.

[0055] Figure 3B differs from Figure 3A in the arrangement of the first coating 20 and the second coating 30. In this example, the first coating 20 is arranged on the inside surface II of the first pane 1. In contrast, the second coating 30 is applied to the outside surface III of the second pane 2.

[0056] Figure 4 shows the layer sequence of an embodiment of the first coating 20 and second coating 30 according to the invention. The first coating 20 and the second coating 30 are each a stack of thin layers.

[0057] The first coating 20 comprises an electrically conductive layer 21 based on silver.

[0058] A metallic blocking layer 24 is arranged directly above the electrically conductive layer. Above this layer is an upper dielectric layer sequence, which consists, from bottom to top, of an upper matching layer 23b, an upper refractive index-increasing layer 23c, and an upper anti-reflective layer 23a.

[0059] Below the electrically conductive layer 21, a lower dielectric layer sequence is arranged, which consists from top to bottom of a lower adaptation layer 22b, a lower refractive index-increasing layer 22c and a lower anti-reflection layer 22a.

[0060] The second coating 30 comprises, directly above the intermediate layer 3, a third purely dielectric layer 33 of titanium dioxide, a second purely dielectric layer 32 comprising a silicon dioxide layer, and a first purely dielectric layer 31 of titanium dioxide.

[0061] Materials and layer thicknesses can be found in the following examples.

[0062] The layer sequences of a composite pane 10 with the first coating 20 on the outer surface III of the second pane 2 and the second coating 30 on the inner surface II of the first pane 1 according to Example 1 of the invention are shown in Table 1, together with the materials and geometric layer thicknesses of the individual layers. The dielectric layers of the first coating 20 can be doped independently of one another, for example with boron or aluminum. Table 1: material Reference symbol Layer thickness TiO 31 30 90 nm SiO 32 150 nm TiO 33 121 nm PVB 3 0.76 mm SiN 23a 20 62 nm SiZrN 23c 10 nm ZnO 23b 10 nm NiCr 24 0.3 nm Ag 21 10.5 nm ZnO 22b 10 nm SiZrN 22c 10 nm SiN 22a 25 nm

[0063] Due to the additional reflection / absorption of thermal radiation by the second coating, the TTS value of laminated pane 10 is improved, or reduced, by up to 5%. This result was unexpected and surprising for the expert. In addition, outer pane 1 is tinted or colored.

[0064] In Figure 5A reflection spectrum of the composite pane 10 with a layer structure according to Table 1 is shown. The reflection spectrum was recorded with a light source that emits P-polarized radiation of uniform intensity in the observed spectral range, viewed across the second pane 2 (the so-called interior-side reflection above the inner pane) at an incidence angle of 65° to the interior-side surface normal. From the graphic representation of the spectrum, it is clear that the coatings according to the invention on the composite pane 10 were able to improve the reflectivity of the composite pane 10, particularly in the IR range (>700 nm), despite an improved TTS value.

[0065] The optical parameters obtained are shown in Table 2 below. Table 2: Inventive example Comparison example TLA 71.4 TL A 71.4 at -5.1 at -1.4 b*t 6.6 b*t 3.7 RL(A) 24.2 RL(A) 24.0 a*c 8° 7.1 a*c 8° -0.8 b*c 8° -9.6 b*c 8° -4,0 RL(A) 60° 32.4 RL(A) 60° 28.4 a*c 60° 4.4 a*c 60° -0.1 b*c 60° -1.9 b*c 60° -2.6 RL(A) p-pol 20.0 RL(A) p-pol 20.5 a*p-pol 3.5 a*p-pol 0.4 b*p-pol -2.2 b*p-pol -2.1 TTS 53.7 TTS 59.8 The following colorimetric coordinates and parameters are listed: Light transmission according to illuminant A: TL A, color values ​​a*t and b*t according to illuminant D65, 10°, light reflection according to illuminant A: RL A, color values ​​a*c and b*c according to light incidence angle 8° illuminant D65,10°, light reflection according to light incidence angle 60°: RL A 60° (light source D60, illuminant A), color values ​​a*c and b*c according to 60° illuminant D65,10°, light reflection according to P-polarized radiation: RL (A) p-pol, illuminant A, color values ​​a*c and b*c according to P-polarized radiation, illuminant D65,10° TTS value

[0066] It can be seen that the example according to the invention exhibited improved optical parameters. A significant advantage of the composite pane 10 according to the invention is that the TTS value is reduced while simultaneously improving reflectivity. List of reference symbols:

[0067] 1First pane 2Second pane 3Thermoplastic interlayer 4Projector 5Viewer / driver 10Laminated pane 20First coating 21Electrically conductive layer 22aFirst lower dielectric layer / anti-reflective layer 22bSecond lower dielectric layer / matching layer 22cThird lower dielectric layer / refractive index-increasing layer 23aFirst upper dielectric layer / anti-reflective layer 23bSecond upper dielectric layer / matching layer 23cThird upper dielectric layer / refractive index-increasing layer 24Metallic blocking layer 30Second coating 31First purely dielectric layer 32Second purely dielectric layer 33Third purely dielectric layer Upper edge of the laminated protective pane 10 Lower edge of the laminated protective pane 10 BHUD area of ​​the laminated protective pane 10 Eyebox IOutside surface of the first pane 1 facing away from the intermediate layer 3 IIInside surface of the first pane 1 facing towards the intermediate layer 3 IIIOutside surface of the second pane 2 facing towards the intermediate layer 3 IVInside surface of the second pane 2 facing away from the intermediate layer 3

Claims

1. Laminated pane for a head-up display, at least comprising • a first pane (1) having a first surface (I) and a second surface (II), a second pane (2) having a first surface (III) and a second surface (IV), and a thermoplastic intermediate layer (3) which is arranged between the second surface (II) of the first pane (1) and the first surface (III) of the second pane (2), • an HUD region (B), and • a first coating (20) for reflecting P-polarized radiation and having exactly one electrically conductive layer (21) based on silver, wherein a second coating (30) is provided for reducing the total transmitted thermal radiation, wherein the first coating (20) is arranged on a surface (III, IV) of the second pane (2) and the second coating (30) is arranged on a surface (I, II) of the first pane (1), and wherein the first pane (1) is tinted or colored.

2. Laminated pane according to claim 1, wherein the first coating (20) is arranged on the first surface (III) of the second pane (2).

3. Laminated pane according to claim 1 or 2, wherein the second coating (30) is arranged on the second surface (II) of the first pane (1).

4. Laminated pane according to any of claims 1 to 3, wherein the second coating (30) comprises a plurality of purely dielectric layers (31, 32, 33).

5. Laminated pane according to any of claims 1 to 4, wherein the second coating (30) comprises, in an alternating manner, at least a first dielectric layer (31) or layer sequence having a refractive index greater than 1.9 and a second dielectric layer (32) or layer sequence having a refractive index less than 1.6.

6. Laminated pane according to claim 5, wherein the first purely dielectric layer (31) or layer sequence comprises silicon nitride, tin oxide, zinc oxide, titanium dioxide, zirconium dioxide, hafnium oxide, vanadium oxide, niobium oxide, tantalum oxide or tungsten oxide.

7. Laminated pane according to claim 5, wherein the second purely dielectric layer (32) or layer sequence comprises SiO2, MgF2 or a nanoporous layer.

8. Laminated pane according to any of claims 1 to 7, wherein the electrically conductive layer has a geometric thickness of 8 nm to 14 nm, in particular 10 nm.

9. Laminated pane according to any of claims 1 to 8, wherein the first coating (20) was deposited by magnetron sputtering and / or the second coating (30) was deposited by magnetron sputtering or by a wet chemical deposition process.

10. Laminated pane according to any of claims 3 to 9, wherein the second coating (30) comprises, directly above the intermediate layer (3), a third purely dielectric layer (33) of titanium dioxide, a second purely dielectric layer (32) having a silicon dioxide layer, and a first purely dielectric layer (31) of titanium dioxide.

11. Laminated pane according to claim 10, wherein a metal blocking layer (24) is arranged directly above the electrically conductive layer (21), and an upper dielectric layer sequence is arranged thereover, which consists, from bottom to top, of an upper adaptation layer (23b), an upper refractive index-increasing layer (23c) and an upper anti-reflection layer (23a).

12. Laminated pane according to claim 11, wherein a lower dielectric layer sequence is arranged below the electrically conductive layer (21), which lower dielectric layer sequence consists, from top to bottom, of a lower adaptation layer (22b), a lower refractive index-increasing layer (22c) and a lower anti-reflection layer (22a).

13. Projection arrangement for a head-up display, at least comprising • a laminated pane (10) according to any of claims 1 to 12, and • a projector (4) directed onto the HUD region (B) of the laminated pane (10), wherein the radiation of the projector (4) is predominantly P-polarized.