DE202023002816U1 - Composite pane with reflective element - Google Patents

Abstract

Composite pane (100), comprising at least
- an outer pane (1) with an outside surface (I) and an inside surface (II),
- a thermoplastic intermediate layer (3),
- an inner pane (2) with an outside surface (III) and an inside surface (IV),
- a masking layer (4),
- an adhesive layer (5),
- a reflection element (6) comprising an optically highly refractive thin glass pane (7) with an outside surface (V), an inside surface (VI), a thickness of 20 µm to 500 µm and a refractive index greater than or equal to 1.9 and an optically low-refractive layer (8) arranged on the inside surface (VI) of the optically highly refractive thin glass pane (7) with a refractive index of less than or equal to 1.6,
wherein the thermoplastic intermediate layer (3) is arranged between the outer pane (1) and the inner pane (2),
the masking layer (4) is arranged between the outer pane (1) and the inner pane (2) or on the interior-side surface (IV) of the inner pane (2) in a region of the composite pane (100),
the adhesive layer (5) is arranged between the inner pane (2) and the reflection element (6),
the outside surface (V) of the optically highly refractive thin glass pane (7) is connected to the inside surface (IV) of the inner pane (2) via the adhesive layer (5),
and the reflection element (6) is arranged in a region of the composite pane (100) which, when viewed perpendicularly through the composite pane (100), lies entirely in the region in which the masking layer (4) is arranged.

Description

The invention relates to a composite pane with a reflection element arranged in certain regions and to a projection arrangement.

To display navigation information in windshields, projection arrangements known as head-up displays (HUDs) consisting of an image display device and a windshield with a wedge-shaped thermoplastic intermediate layer and/or wedge-shaped panes are often used. A wedge angle is necessary to avoid double images. The projected image appears in the form of a virtual image at a certain distance from the windshield, so that the driver of the motor vehicle perceives the projected navigation information as being on the road in front of him, for example. The radiation from HUD image display devices is typically essentially s-polarized, due to the better reflection characteristics of the windshield compared to p-polarization. However, if the viewer wears polarization-selective sunglasses that do not transmit s-polarized light, he will at best perceive the HUD image in a weakened form. One solution to this problem is the use of projection arrangements that use p-polarized light.

EN 10 2014 220 189 A1 discloses a head-up display projection arrangement operated with p-polarized radiation, wherein the windshield has a reflective structure that reflects p-polarized radiation towards the viewer. Also US20040135742 A1 discloses a head-up display projection arrangement using p-polarized radiation having a reflective structure. In WO96/19347A3 A multilayer polymer layer is proposed as a reflective structure.

WO 2021/122848 A1 discloses a HUD system comprising a light source that projects p-polarized light onto a glazing, the glazing comprising an outer glass pane having a first surface and a second surface and an inner glass pane having a first surface and a second surface, the second surface of the inner glass pane comprising a reflective coating, both panes being connected by at least one layer of interlayer material, the reflective coating comprising at least one high refractive index layer having a thickness of 50 to 100 nm and at least one low refractive index layer having a thickness of 70 to 160 nm, the at least one high refractive index layer comprising at least one of an oxide of Zr, Nb, Sn, a mixed oxide of Ti, Zr, Nb, Si, Sb, Sn, Zn, In, a nitride of Si, Zr and a mixed nitride of Si, Zr.

WO 2021/145387 A1 discloses a HUD system, wherein the composite pane is provided in regions with a reflection element for p-polarized light. The reflection element can be a reflection film for p-polarized light, which is attached to the interior surface of the inner pane by means of an adhesion promoter layer, or a reflection coating for p-polarized light arranged on the interior surface of the inner pane, wherein the reflection coating has at least one layer made of a material with a high refractive index and at least one layer made of a material with a low refractive index.

In CN114035322A discloses a head-up display glass comprising laminated glass, the laminated glass comprising a first surface and a second surface opposite to each other, the second surface comprising a display region and a non-display region, the display region being provided with a first nanofilm having at least a first high refractive index layer and at least a first low refractive index layer stacked sequentially outward from the second surface, the refractive index of the first high refractive index layer being 1.9 to 2.7 and the refractive index of the first low refractive index layer being 1.3 to 1.8.

US 2020/0333593 A1 discloses a composite pane for a HUD system having a first nanostructured coating on the outside surface of the outer pane, a second nanostructured coating on the inside surface of the inner pane, and a reflective coating between the inside surface of the inner pane and the second nanostructured coating.

JP 2016 097781 A discloses a HUD system comprising a windshield glass, a low reflection layer formed on the inside of the windshield glass, and a hardened layer formed on the outside of the windshield glass, wherein the hardened Layer a transparent tempered film with a refractive index of 2.0 or more and a glass with a high refractive index can be used.

Reflective coatings applied to the inside of the laminated pane may have the disadvantage that they have a low color neutrality of images reflected on the reflective coatings and fingerprints or contamination on the reflective coatings lead to a significant shift of the reflection spectrum to higher wavelengths.

When designing a display based on head-up display technology, it must also be ensured that the image display device has a sufficiently high output so that the projected image is sufficiently bright, especially when exposed to sunlight, and is easily visible to the viewer. This requires a certain size of the image display device and is associated with a corresponding power consumption.

WO 2022/073894 A1 discloses a vehicle window for a head-up display with an outer side facing an external environment in the installed state and an inner side facing a vehicle interior, comprising at least one transparent pane, at least one masking strip in an edge region of the pane and at least one reflective layer applied by printing for reflecting light, which is arranged in the region of the masking strip, on the vehicle interior side of the masking strip.

WO 2022/073860 A1 discloses a vehicle window for a head-up display with an outer side facing an external environment in the installed state and an inner side facing a vehicle interior, comprising at least one transparent window, at least one masking strip in an edge region of the window and at least one light-directing device for directing light into the vehicle interior or at least one image display device for displaying image information, which is arranged in the region of the masking strip, on the vehicle interior side of the masking strip.

EN 10 2009 020 824 A1 discloses a windshield virtual image system that enables an image source to be reflected on the windshield so that a virtual image free of ghosting is seen by the driver. Either a matte black material is applied to a windshield glass pane on any of the windshield surfaces of the outer glass pane, or on the windshield surface of the inner glass pane, or else a black glossy layer is applied to a windshield surface on the windshield frit, thereby providing the virtual image for any image source with real image rays incident on the windshield surface.

The present invention is based on the object of providing an improved composite pane with a reflection element and an improved projection arrangement comprising such a composite pane.

The object of the present invention is achieved by a composite pane and a projection arrangement according to the independent claims. Preferred embodiments emerge from the subclaims.

The composite pane according to the invention comprises an outer pane, a thermoplastic intermediate layer, a masking layer, an inner pane, an adhesive layer and a reflective element. The thermoplastic intermediate layer is arranged between the outer pane and the inner pane and the adhesive layer is arranged between the inner pane and the reflective element. According to the invention, the masking layer is arranged in a region of the composite pane and the reflective element is arranged in a region of the composite pane which, when viewed perpendicularly through the composite pane, lies entirely in the region in which the masking layer is arranged.

The reflection element comprises a thin glass pane with a high optical refractive index and a layer with a low optical refractive index. The thin glass pane with a high optical refractive index has a thickness of 20 µm (micrometers) to 500 µm and has a refractive index of at least 1.9, i.e. the refractive index of the thin glass pane with a high optical refractive index is greater than or equal to 1.9. The layer with a low optical refractive index has a refractive index of at most 1.6, i.e. the refractive index of the layer with a low optical refractive index is less than or equal to 1.6.

The composite pane is designed to separate the interior from the outside environment in a window opening of a vehicle. In the context of the invention, the inner pane refers to the pane of the composite pane facing the vehicle interior. The outer pane refers to the pane facing the outside environment.

The composite pane has in particular an upper edge and a lower edge, as well as two side edges running between them. The upper edge refers to the edge that is intended to point upwards in the installation position. The lower edge refers to the edge that is intended to point downwards in the installation position. In the case of a windshield, the upper edge is often referred to as the roof edge and the lower edge as the engine edge.

The outer pane, the inner pane and the optically highly refractive thin glass pane each have an outer surface and an inner surface and a circumferential side edge running between them. In the sense of the invention, the outer surface refers to the main surface which is intended to face the outside environment in the installed position. In the sense of the invention, the inner surface refers to the main surface which is intended to face the interior in the installed position. The inner surface of the outer pane and the outer surface of the inner pane face each other and are connected to one another by the thermoplastic intermediate layer. The inner surface of the inner pane and the outer surface of the optically highly refractive thin glass pane face each other and are connected to one another by the adhesive layer.

According to the invention, the optically low-refractive layer is arranged on the interior-side surface of the optically high-refractive thin glass pane. The optically low-refractive layer is thus designed as a full-surface coating of the interior-side surface of the optically high-refractive thin glass pane.

The outside surface of the outer pane is referred to as side I. The inside surface of the outer pane is referred to as side II. The outside surface of the inner pane is referred to as side III. The inside surface of the inner pane is referred to as side IV. The outside surface of the optically highly refractive thin glass pane is referred to as side V. The inside surface of the optically highly refractive thin glass pane is referred to as side VI.

It is understood that the inner pane is arranged between the outer pane and the optically highly refractive thin glass pane.

The outside surface of the optically highly refractive thin glass pane is connected to the inside surface of the inner pane via the adhesive layer.

The interior surface of the inner pane is the surface of the inner pane closest to the reflective element.

The masking layer is arranged between the outer pane and the inner pane or on the interior surface of the inner pane. Thus, when the composite pane is installed in a vehicle, the reflection element is closer to the vehicle interior than the masking layer.

As described above, the outside surface of the optically highly refractive thin glass pane is connected to the interior surface of the inner pane via the adhesive layer. It is understood that in embodiments in which the masking layer is arranged on the interior surface of the inner pane, the outside surface of the optically highly refractive thin glass pane is not directly connected to the interior surface of the inner pane via the adhesive layer, but indirectly, since in these embodiments the masking layer arranged on the interior surface of the inner pane is arranged between the adhesive layer and the interior surface of the inner pane.

As described above, the optically highly refractive thin glass pane has a thickness of 20 µm (micrometers) to 500 µm. The optically highly refractive thin glass pane is therefore a pane made of ultra-thin glass. Such a pane made of ultra-thin glass is flexible and can be adapted to the curvature of a pane.

In a preferred embodiment of the composite pane according to the invention, the optically highly refractive thin glass pane has a thickness of 50 µm to 300 µm, preferably from 50 µm to 200 µm, for example 100 µm.

The refractive index of the optically highly refractive thin glass pane is preferably at least 2.0, particularly preferably at least 2.1, most particularly preferably at least 2.3.

The refractive index of the optically highly refractive thin glass pane is preferably no more than 2.4.

In a preferred embodiment of the composite pane according to the invention, the refractive index of the optically highly refractive thin glass pane is between 1.9 and 2.4. In a further preferred embodiment of the composite pane according to the invention, the refractive index of the optically highly refractive thin glass pane is between 2.0 and 2.4. In a further preferred embodiment of the composite pane according to the invention, the refractive index of the optically highly refractive thin glass pane is between 2.1 and 2.4. In a further preferred embodiment of the composite pane according to the invention, the refractive index of the optically highly refractive thin glass pane is between 2.3 and 2.4.

The refractive index of the optically low-refractive layer is preferably at most 1.5, particularly preferably at most 1.4. In particular, the refractive index of the optically low-refractive layer is between 1.2 and 1.5. The refractive index of the optically low-refractive layer is, for example, 1.3 or 1.45. These values have proven to be particularly advantageous with regard to the reflection properties of the pane.

In a preferred embodiment of the composite pane according to the invention, the optically low-refractive layer has a thickness of 50 nm to 200 nm, preferably 100 nm to 150 nm, in particular 120 nm.

Refractive indices are generally given in relation to a wavelength of 550 nm within the scope of the present invention. Methods for determining refractive indices are known to those skilled in the art. The refractive indices given within the scope of the invention can be determined, for example, by means of ellipsometry, whereby commercially available ellipsometers can be used. The specification of layer thicknesses or thicknesses refers, unless otherwise stated, to the geometric thickness of a layer.

The optically low-refractive layer is preferably based on silicon dioxide, doped silicon oxide, magnesium fluoride or calcium fluoride.

The silicon oxide can be doped with aluminum, zirconium, titanium, boron or hafnium, for example. Doping can be used to adjust the optical, mechanical and chemical properties of the coating.

The optically low-refractive layer is preferably applied to the interior surface of the optically high-refractive thin glass pane by magnetic field-assisted cathode sputtering ("magnetron sputtering") or by wet coating. The optically low-refractive layer can also be applied to the interior surface of the optically high-refractive thin glass pane by means of a sol-gel process, for example.

In a preferred embodiment, the optically low-refractive layer is formed on the basis of nanoporous silicon oxide. The reflection properties of such a layer are determined on the one hand by the refractive index and on the other hand by the thickness of the optically low-refractive layer. The refractive index in turn depends on the pore size and the density of the pores. The nanoporous silicon oxide can be doped, for example with aluminum, zirconium, titanium, boron, tin or zinc. Doping can be used to adjust the optical, mechanical and chemical properties of the coating in particular. An optically low-refractive layer formed on the basis of nanoporous silicon oxide preferably comprises only one homogeneous layer of nanoporous silicon oxide. However, it is also possible to form the low-refractive layer from several layers of nanoporous silicon oxide that differ, for example, in terms of porosity (size and/or density of the pores). In this way, a progression of refractive indices can be created. The pores are in particular closed nanopores, but can also be open pores. Nanopores are pores that have sizes in the nanometer range, i.e. from 1 nm to less than 1000 nm (1 µm). The pores are sen preferably have a substantially circular cross-section (spherical pores), but can also have other cross-sections, for example an elliptical, oval or elongated cross-section (ellipsoidal or ovoid pores). Preferably, at least 80% of all pores have substantially the same cross-sectional shape. It can be advantageous if the pore size is at least 20 nm or even at least 40 nm. The average size of the pores is preferably from 1 nm to 500 nm, particularly preferably from 1 nm to 100 nm, very particularly preferably from 20 nm to 80 nm. The size of the pores is understood to mean the diameter in the case of circular pores, and the greatest longitudinal extent in the case of pores of a different shape. Preferably, at least 80% of all pores have sizes in the specified ranges, particularly preferably the sizes of all pores are in the specified ranges. The proportion of pore volume in the total volume is preferably between 10% and 90%, particularly preferably less than 80%, most preferably less than 60%.

An optically low-refractive layer based on nanoporous silicon oxide is preferably a sol-gel coating. It is deposited in a sol-gel process on the interior surface of the optically high-refractive thin glass pane. First, a sol containing the precursors of the coating is provided and matured. The maturation can involve hydrolysis of the precursors and/or a (partial) reaction between the precursors. In the sense of the invention, this sol is referred to as a precursor sol and contains silicon oxide precursors in a solvent. The precursors are preferably silanes, in particular tetraethoxysilanes or methyltriethoxysilane (MTEOS). Alternatively, silicates can also be used as precursors, in particular sodium, lithium or potassium silicates, for example tetramethyl orthosilicate, tetraethyl orthosilicate (TEOS), tetraisopropyl orthosilicate, or organosilanes of the general form R ² _n Si(OR ¹ ) _4-n . Preferably, R ¹ is an alkyl group, R ² is an alkyl, epoxy, acrylate, methacrylate, amine, phenyl or vinyl group, and n is an integer from 0 to 2. Silicon halides or alkoxides can also be used. The solvent is preferably water, alcohol (especially ethanol) or a water-alcohol mixture. The precursor sol is then mixed with a pore former that is dispersed in an aqueous phase. The task of the pore former is to create the pores in the silicon oxide matrix as a placeholder when producing the low-refractive layer. The shape, size and density of the pores are determined by the shape, size and concentration of the pore former. The pore former can be used to specifically control the pore size, pore distribution and pore density and ensure reproducible results. Polymer nanoparticles can be used as pore formers, for example, preferably PMMA nanoparticles (polymethyl methacrylate), but alternatively nanoparticles made of polycarbonates, polyesters or polystyrenes, or copolymers of methyl (meth)acrylates and (meth)acrylic acid. Instead of polymer nanoparticles, nanodrops of an oil in the form of a nanoemulsion can also be used. Of course, it is also conceivable to use various pore formers. The solution obtained in this way is applied to the interior surface of the thin glass pane with a high optical refractive index. This is best done using wet-chemical processes. The sol is then condensed. The silicon oxide matrix forms around the pore formers. The condensation can include a temperature treatment, for example at a temperature of up to 350 °C. If the precursors have UV-crosslinkable functional groups (for example methacrylate, vinyl or acrylate groups), the condensation can include a UV treatment. The condensation can alternatively comprise an IR treatment for suitable precursors (for example silicates). Optionally, solvent can be evaporated at a temperature of up to 120 °C. The pore former is then optionally removed again. For this purpose, the coated substrate is preferably subjected to a heat treatment at a temperature of at least 400 °C, preferably at least 500 °C, during which the pore formers decompose. Organic pore formers are in particular charred (carbonized). The heat treatment can take place as part of a bending process or thermal prestressing process. The heat treatment is preferably carried out over a period of at most 15 minutes, particularly preferably at most 5 minutes. In addition to removing the pore formers, the heat treatment can also serve to complete the condensation and thereby compact the coating, which improves its mechanical properties, in particular its stability. Instead of using the heat treatment, the pore former can also be dissolved out of the coating using solvents. In the case of polymer nanoparticles, the corresponding polymer must be soluble in the solvent; for example, in the case of PMMA nanoparticles, tetrahydrofuran (THF) can be used. Removing the pore former is preferred, which creates empty pores. In principle, however, it is also possible to leave the pore former in the pores. If it has a different refractive index than the silicon oxide, this will affect it. The pores are then filled with the pore former, for example with PMMA nanoparticles. Hollow particles can also be used as pore formers, for example hollow polymer nanoparticles such as PMMA nanoparticles or hollow silicon oxide nanoparticles. If such a pore former is left in the pores and not removed, the pores have a hollow core and an edge area filled with the pore former.

The sol-gel process described enables the production of a low-refractive optical layer with a regular, homogeneous distribution of pores. The pore shape, size and density can be specifically adjusted and the low-refractive optical layer has a low tortuosity.

Because the reflective element is arranged in an area of the composite pane that, when viewed vertically through the composite pane, lies entirely in the area in which the masking layer is arranged, the reflective element has no section that does not overlap the masking layer, i.e. the reflective element is only formed where it is located in front of the masking layer when viewed through the composite pane from the inside. From the perspective of a vehicle occupant, the reflective element is thus spatially arranged in front of the masking layer.

As described above, in the composite pane according to the invention, a masking layer is arranged in one of the areas of the composite pane. The masking layer is preferably arranged in an edge area of the composite pane, which typically borders the edge of the pane. The great advantage of this arrangement arises when the composite pane is used in a vehicle as a windshield, since the masking layer is arranged in an edge area outside the driver's main field of vision.

The masking layer is preferably arranged at least along the lower edge and adjacent to the lower edge. This results in a rectangular opaque strip arranged along the lower edge in the plan view of the composite pane.

In a particularly preferred embodiment of the composite pane according to the invention, the masking layer is designed in a frame-shaped manner all the way around. In a section in which the reflection element is arranged to overlap the masking layer, the frame-shaped masking layer is preferably provided with a widening, i.e. has a greater width (dimension perpendicular to the extension) than in other sections. In this way, the masking layer can be adapted in a suitable manner to the dimensions of the reflection element.

In one embodiment, the masking layer is thus formed in a frame-shaped manner and has a greater width, in particular in a section which overlaps the reflection element, than in sections different therefrom.

A masking layer in the form of a frame is preferably used to mask the bonding of the composite pane, for example as a windshield in a vehicle body. This creates a harmonious overall impression of the composite pane when installed. Furthermore, such a masking layer serves as UV protection for the adhesive material used.

One advantage of the invention is that the reflective element is attached to the interior-side surface of the inner pane. The surface on which the masking layer is to be placed can therefore be freely selected according to customer requirements. In contrast, a reflective element attached to the outside surface of the inner pane or the interior-side surface of the outer pane could be covered by a masking print located further towards the vehicle interior. This is avoided by means of the structure according to the invention. If the masking layer is arranged on the interior-side surface of the inner pane, the adhesive layer is attached to the surface of the masking layer facing away from the inner pane and thus the function of the reflective element is not impaired by the masking layer.

The reflection element and thus the optically high-refractive thin glass pane with the optically low-refractive layer applied to the interior surface preferably has essentially the shape of a rectangle that extends in an area close to the lower edge between the two side edges of the composite pane. Particularly preferably, the edges of the optically high-refractive thin glass pane of the reflection element do not reach the side edges and the lower edge of the composite pane, but are spaced from them by 2 cm to 5 cm, for example.

The reflection element is arranged in an area of the composite pane as described above. The reflection element does not extend over the entire composite pane. Thus, the reflection element is smaller in terms of its external dimensions, i.e. the width and length, than the outer pane and the inner pane of the composite pane. The reflection element preferably extends over a maximum of 50%. particularly preferably over a maximum of 30%, most preferably over a maximum of 20% of the laminated pane.

The masking layer in the sense of the invention is a layer that prevents visibility through the composite pane. In this case, a transmission of at most 5%, preferably at most 2%, particularly preferably at most 1%, in particular at most 0.1%, of the light of the visible spectrum through the masking layer takes place. The masking layer is therefore an opaque masking layer, preferably a black masking layer.

The masking layer is preferably a coating made of one or more layers. Alternatively, the masking layer can also be a colored area of the thermoplastic intermediate layer. According to a preferred embodiment of the composite pane, the masking layer consists of a single layer. This has the advantage of a particularly simple and cost-effective production of the composite pane, since only a single layer has to be formed for the masking layer.

The masking layer is in particular an opaque cover print made of a dark, preferably black, enamel.

In a preferred embodiment, the masking layer is formed as an opaque cover print arranged on the interior surface of the outer pane, in particular made of a dark, preferably black, enamel.

In an alternative preferred embodiment, the masking layer is formed as an opaque cover print arranged on the outer surface of the inner pane, in particular made of a dark, preferably black, enamel.

In an alternative preferred embodiment, the masking layer is formed as an opaque cover print arranged on the interior-side surface of the inner pane, in particular made of a dark, preferably black, enamel.

In an alternative preferred embodiment, the masking layer is formed as an opaque colored region of the thermoplastic intermediate layer. In one embodiment, the thermoplastic intermediate layer is formed in one piece and is colored opaque in one region. A masking layer formed as an opaque colored region of the thermoplastic intermediate layer can also be realized by using a thermoplastic intermediate layer composed of an opaque thermoplastic film and a transparent thermoplastic film. The opaque thermoplastic film and transparent thermoplastic film are preferably arranged offset from one another so that both films do not overlap when viewed through the composite pane. The transparent and opaque thermoplastic films consist of the same plastic or preferably contain the same plastic. The materials on the basis of which the opaque thermoplastic film and the transparent thermoplastic film can be formed are those that are also described for the thermoplastic intermediate layer. The opaque thermoplastic film is preferably a colored film that can have different colors, in particular black.

The adhesive layer is preferably a thermoplastic layer or an optically clear adhesive (OCA). Suitable optically clear adhesives, so-called optical clear adhesives (OCA), are known to those skilled in the art. An adhesive layer formed as a thermoplastic 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 thermoplastic layer is typically formed from a thermoplastic film (connecting film). The thickness of the thermoplastic layer is preferably from 0.2 mm to 2 mm, particularly preferably from 0.3 mm to 1 mm, for example 760 µm. The thermoplastic layer can be formed by a single film or by more than one film.

The composite pane is preferably curved in one or more directions of space, as is usual for vehicle windows, with typical radii of curvature in the range of about 10 cm to about 40 m. The composite pane can also be flat, for example if it is intended as a pane for buses, trains or tractors.

The thermoplastic intermediate layer, via which the outer pane is connected to the inner pane, 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 thermoplastic intermediate layer is typically made from a thermoplastic film (connecting film). The thickness of the thermoplastic intermediate layer is preferably from 0.2 mm to 2 mm, particularly preferably from 0.3 mm to 1 mm, for example 760 µm. The thermoplastic intermediate layer can be made from a single film or from more than one film. The thermoplastic intermediate layer can also be a film with functional properties, for example a film with acoustically dampening properties.

The outer pane and inner pane preferably contain or consist of glass, particularly preferably flat glass, float glass, quartz glass, borosilicate glass, soda-lime glass, alumino-silicate glass, or clear plastics, preferably rigid clear plastics, in particular polyethylene, polypropylene, polycarbonate, polymethyl methacrylate, polystyrene, polyamide, polyester, polyvinyl chloride and/or mixtures thereof.

The outer pane and the inner pane can be clear and colorless, but also tinted or colored. The outer pane and the inner pane can be non-tempered, partially tempered or tempered independently of one another. If at least one of the panes is to be tempered, this can be thermal or chemical tempering.

The composite pane according to the invention is preferably designed as a windshield. In a preferred embodiment, the total transmission through the windshield in the main viewing area is greater than 70% (illuminant type A). The term total transmission refers to the method for testing the light transmission of motor vehicle windows specified in ECE-R 43, Annex 3, Section 9.1.

The outer pane and inner pane can have suitable coatings known per se, for example anti-reflective coatings, non-stick coatings, anti-scratch coatings, photocatalytic coatings or sun protection coatings or low-E coatings.

The thickness of the outer pane and the inner pane can vary widely and can thus be adapted to the requirements in individual cases. The outer pane and the inner pane preferably have thicknesses of 0.5 mm to 5 mm, particularly preferably 1 mm to 3 mm, and very particularly preferably 1.6 mm to 2.1 mm. For example, the outer pane has a thickness of 2.1 mm and the inner pane has a thickness of 1.6 mm. The outer pane or in particular the inner pane can also be thin glass with a thickness of, for example, 0.55 mm.

The optically highly refractive thin glass pane is preferably a so-called flint glass. Typically, optically highly refractive glasses contain doping with elements such as lead, barium or lanthanum. The optically highly refractive thin glass pane can, for example, be made like the one in EN 11 2011 104 339 B4 , DE10 2020 120 171 A1 or WO 2019/131123 A1 disclosed high refractive index glasses.

The composite pane according to the invention can comprise one or more additional intermediate layers, in particular functional intermediate layers. An additional intermediate layer can in particular be an intermediate layer with acoustically dampening properties, an intermediate layer that reflects infrared radiation, an intermediate layer that absorbs infrared radiation, an intermediate layer that absorbs UV radiation, an intermediate layer that is colored at least in sections and/or an intermediate layer that is tinted at least in sections. If several additional intermediate layers are present, these can also have different functions. The additional intermediate layers are preferably arranged between the inner pane and the outer pane.

In one embodiment, the composite pane comprises a HUD reflection layer, hereinafter also referred to as HUD layer, arranged between the interior surface of the outer pane and the outside surface of the inner pane.

The principle of a head-up display (HUD) and the technical terms used here from the field of HUDs are generally known to the expert. For a detailed description, please refer to the dissertation “Simulation-based measurement technology for testing head-up displays” by Alexander Neumann at the Institute of Computer Science at the Technical University of Munich (Munich: University Library of the TU Munich, 2012), in particular to Chapter 2 “The head-up display”. The HUD layer is between the The HUD layer is arranged between the outer pane and the inner pane, where “between” can mean both within the thermoplastic intermediate layer and in direct spatial contact on the interior surface of the outer pane and on the outside surface of the inner pane. The HUD layer is designed to reflect p-polarized light. The HUD layer is a reflective coating that is applied over a large area in the composite pane, whereby the area in which the HUD coating is located is also referred to as the HUD area. To use the composite pane as a head-up display, a projector is aimed at the HUD area of the composite pane. The radiation from the projector is preferably predominantly p-polarized. The HUD layer is suitable for reflecting p-polarized radiation. This creates a virtual image from the projector radiation, which the driver of a vehicle can see from behind the composite pane.

Because the reflective element is connected to the interior surface of the inner pane via the adhesive layer, the HUD layer can be arranged independently of the reflective element between the outer pane and the inner pane of the composite pane and is protected there from environmental influences.

The HUD layer preferably comprises at least one metal selected from the group consisting of aluminum, tin, titanium, copper, chromium, cobalt, iron, manganese, zirconium, cerium, yttrium, silver, gold, platinum and palladium, or mixtures thereof. In a preferred embodiment of the invention, the HUD layer is a coating containing a thin-film stack, i.e. a layer sequence of thin individual layers. This thin-film stack contains one or more electrically conductive layers based on silver. The electrically conductive layer based on silver gives the reflective coating the basic reflective properties and also an IR-reflecting effect and electrical conductivity. The electrically conductive layer is based on silver. The conductive layer preferably contains at least 90% by weight of silver, particularly preferably at least 99% by weight of silver, very particularly preferably at least 99.9% by weight of silver. The silver layer can have doping, for example palladium, gold, copper or aluminum. Materials based on silver are particularly suitable for reflecting p-polarized light. The use of silver has proven to be particularly advantageous in the reflection of p-polarized light. The coating has a thickness of 5 nm to 50 nm and preferably 8 nm to 25 nm. If the HUD layer is designed as a coating, it is preferably applied to the inner or outer pane by physical vapor deposition (PVD), particularly preferably by cathode sputtering (“sputtering”) and most particularly preferably by magnetic field-assisted cathode sputtering (“magnetron sputtering”). In principle, however, the coating can also be applied, for example, by chemical vapor deposition (CVD), for example plasma-enhanced vapor deposition (PECVD), by vapor deposition or by atomic layer deposition (ALD). The coating is applied to the panes before lamination.

The HUD layer can also be designed as a reflective film that reflects p-polarized light. The HUD layer can be a carrier film with a reflective coating or a reflective polymer film. The reflective coating preferably comprises at least one layer based on a metal and/or a dielectric layer sequence with alternating refractive indices. The layer based on a metal preferably contains silver and/or aluminum, or consists thereof. The dielectric layers 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 or silicon carbide. The oxides and nitrides mentioned can be deposited stoichiometrically, substoichiometrically or superstoichiometrically. They can have dopants, for example aluminum, zirconium, titanium or boron. The reflective polymer film preferably comprises dielectric polymer layers or consists thereof. The dielectric polymer layers preferably contain PET. If the HUD layer is designed as a reflective film, it is preferably from 30 µm to 300 µm, particularly preferably from 50 µm to 200 µm and in particular from 100 µm to 150 µm thick. If it is a coated, reflective film, the CVD or PVD coating processes can also be used for production. According to a further preferred embodiment, the HUD layer is designed as a reflective film and arranged within the thermoplastic intermediate layer. The advantage of this arrangement is that the HUD layer does not have to be applied to the outer or inner pane using thin-film technology (for example CVD and PVD). This results in uses of the HUD layer with further advantageous functions such as a more homogeneous reflection of the p-polarized light on the HUD layer. In addition, the production of the composite pane can be simplified because the HUD layer does not have to be arranged on the outer or inner pane using an additional process before lamination.

The invention also relates to a projection arrangement comprising at least one composite pane according to the invention and an imaging unit directed at the reflection element, which emits p-polarized light, wherein the interior-side surface of the inner pane is the surface of the inner pane closest to the imaging unit.

• - eine Verbundscheibe, mindestens umfassend eine Außenscheibe mit einer außenseitigen Oberfläche und einer innenraumseitigen Oberfläche, eine thermoplastische Zwischenschicht, eine Innenscheibe mit einer außenseitigen Oberfläche und einer innenraumseitigen Oberfläche, eine Maskierungsschicht, eine Klebeschicht und ein Reflexionselement umfassend eine optisch hochbrechende Dünnglasscheibe mit einer außenseitigen Oberfläche, einer innenraumseitigen Oberfläche, einer Dicke von 20 µm bis 500 µm und einem Brechungsindex von größer oder gleich 1,9 und eine auf der innenraumseitigen Oberfläche der optisch hochbrechenden Dünnglasscheibe aufgetragene optisch niedrig brechende Schicht mit einem Brechungsindex von kleiner oder gleich 1,6, wobei die thermoplastische Zwischenschicht zwischen der Außenscheibe und der Innenscheibe angeordnet ist, die Klebeschicht zwischen der Innenscheibe und dem Reflexionselement angeordnet ist, die Maskierungsschicht zwischen der Außenscheibe und der Innenscheibe oder auf der innenraumseitigen Oberfläche der Innenscheibe in einem Bereich der Verbundscheibe angeordnet ist, die außenseitige Oberfläche der optisch hochbrechenden Dünnglasscheibe über die Klebeschicht mit der innenraumseitigen Oberfläche der Innenscheibe verbunden ist, und wobei das Reflexionselement in einem Bereich der Verbundscheibe angeordnet ist, der bei senkrechter Durchsicht durch die Verbundscheibe vollständig in dem Bereich liegt, in dem die Maskierungsschicht angeordnet ist,
• - und eine auf das Reflexionselement gerichtete bildgebende Einheit, welche p-polarisiertes Licht emittiert,

wobei die innenraumseitige Oberfläche der Innenscheibe die der bildgebenden Einheit nächstliegende Oberfläche der Innenscheibe ist.According to the invention, a projection arrangement is thus also provided which at least comprises

• - a composite pane, at least comprising an outer pane with an outer surface and an interior surface, a thermoplastic intermediate layer, an inner pane with an outer surface and an interior surface, a masking layer, an adhesive layer and a reflection element comprising an optically highly refractive thin glass pane with an outer surface, an interior surface, a thickness of 20 µm to 500 µm and a refractive index of greater than or equal to 1.9 and an optically low refractive layer applied to the interior surface of the optically highly refractive thin glass pane with a refractive index of less than or equal to 1.6, wherein the thermoplastic intermediate layer is arranged between the outer pane and the inner pane, the adhesive layer is arranged between the inner pane and the reflection element, the masking layer is arranged between the outer pane and the inner pane or on the interior surface of the inner pane in a region of the composite pane, the outer surface of the optically highly refractive thin glass pane is connected to the interior surface via the adhesive layer. surface of the inner pane, and wherein the reflection element is arranged in a region of the composite pane which, when viewed perpendicularly through the composite pane, lies entirely in the region in which the masking layer is arranged,
• - and an imaging unit directed at the reflection element which emits p-polarized light,

wherein the interior-side surface of the inner pane is the surface of the inner pane closest to the imaging unit.

In particular, the combination of the reflection element with the masking layer behind it from the perspective of a vehicle occupant results in good visibility of the image in a projection arrangement according to the invention, even in the presence of external sunlight and when using low-light imaging units. Even under these circumstances, the image generated by the imaging unit appears bright and is clearly recognizable. This enables a reduction in the performance of the imaging unit and thus a reduced energy consumption.

From the perspective of a vehicle occupant, the reflective element is arranged spatially in front of the masking layer when viewed through the inner pane. The area of the composite pane in which the reflective element is arranged therefore appears opaque. The expression “when viewed through the composite pane” means that the composite pane is viewed from the inside, i.e. the interior surface of the inner pane is the surface of the inner pane closest to the viewer. In the sense of the present invention, “spatially in front” means that the reflective element is arranged spatially further away from the outside surface of the outer pane than the masking layer. The masking layer is preferably widened at least in the area that overlaps with the reflective element. This means that the masking layer in this area, viewed perpendicular to the closest section of the peripheral edge of the composite pane, has a greater width than in other sections. The masking layer can be adapted in this way to the dimensions of the reflective element.

The imaging unit is used to emit an image, and can therefore also be referred to as a projector, display device or image display device. A display or another device known to the person skilled in the art can also be used as an imaging unit. The imaging unit is preferably a display, particularly preferably an LCD display, LED display, OLED display or electroluminescent display, in particular an LCD display. Displays have a low installation height and can therefore be easily and space-savingly integrated into the dashboard of a vehicle. In addition, displays are much more energy-efficient to operate than other imaging units. The comparatively lower brightness of displays is completely sufficient in the inventive combination of the reflection element with the masking layer behind it. The imaging unit emits p-polarized light. The radiation from the imaging unit preferably hits a Angle of incidence of 55° to 80°, preferably 62° to 77°, on the composite pane in the area of the reflection element. The angle of incidence is the angle between the incidence vector of the radiation of the imaging unit and the surface normal in the geometric center of the reflection element.

The p-polarized light emitted by the imaging unit hits the reflection element and is reflected there. The light reflected by the reflection element is preferably visible light, i.e. light in a wavelength range of approximately 380 nm to 780 nm. The reflection element preferably has a high and uniform degree of reflection (over different angles of incidence) with respect to p-polarized radiation, so that a high-intensity and color-neutral image representation is guaranteed.

Preferably, the reflection element reflects at least 3%, particularly preferably at least 4%, very particularly preferably at least 6%, in particular at least 10% of the p-polarized light incident on the reflection element in a wavelength range from 400 nm to 700 nm and angles of incidence from 62° to 77°.

The term p-polarized light refers to light from the visible spectral range that consists predominantly of light that has a p-polarization. The p-polarized light preferably has a light component with p-polarization of greater than or equal to 50%, preferably greater than or equal to 70%, particularly preferably greater than or equal to 90% and in particular of approximately 100%.

The indication of the direction of polarization refers to the plane of incidence of the radiation on the composite pane. 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 spanned by the incidence vector and the surface normal of the composite pane in the geometric center of the irradiated area. In other words, the polarization, i.e. in particular the proportion of p- and s-polarized radiation, is determined at a point in the area irradiated by the imaging unit, preferably in the geometric center of the irradiated area. Since composite panes can be curved (for example, when they are designed as a windshield), which affects the plane of incidence of the radiation of the imaging unit, slightly different polarization proportions can occur in the other areas, which is unavoidable for physical reasons.

The inventors have found that a reflection element comprising a thin glass pane with a high optical refractive index and a thickness of 20 µm to 500 µm and a refractive index greater than or equal to 1.9 and a low-refractive layer with a refractive index of less than or equal to 1.6 has particularly uniform reflection behavior and thus better color neutrality and is also less sensitive to fingerprints than a reflection layer comprising an optically high-refractive layer and an optically low-refractive layer. In addition, the combination of the reflection element according to the invention with the masking layer behind it from the perspective of a vehicle occupant results in good visibility of the image, even in external sunlight, for occupants wearing sunglasses and when using low-light imaging units. Even under these circumstances, the image generated by the imaging unit appears bright and is clearly recognizable. This enables a reduction in the performance of the imaging unit and thus reduced energy consumption.

The projection arrangement according to the invention is particularly suitable for combination with a HUD layer. In this case, the composite pane has a HUD layer as described above in an embodiment of the composite pane according to the invention, which is arranged between the outer pane and the inner pane. In this embodiment, the reflection element and the masking layer applied in this area are only locally limited to the edge area of the composite pane and thus do not influence the HUD layer applied in the see-through area of the composite pane.

The composite pane of the projection arrangement is preferably a windshield. The optional HUD layer is located at least in the main viewing area of the windshield.

The preferred embodiments of the composite pane according to the invention described above also apply accordingly to the projection arrangement according to the invention comprising a composite pane according to the invention and an imaging unit and vice versa.

1. a) Bereitstellung eines Verbunds aus einer Außenscheibe mit einer außenseitigen Oberfläche und einer innenraumseitigen Oberfläche, einer thermoplastischen Zwischenschicht und einer Innenscheibe mit einer außenseitigen Oberfläche und einer innenraumseitigen Oberfläche, wobei die thermoplastische Zwischenschicht zwischen der Außenscheibe und der Innenscheibe angeordnet ist und zwischen der Außenscheibe und der Innenscheibe oder auf der innenraumseitigen Oberfläche der Innenscheibe in einem Bereich eine Maskierungsschicht angeordnet ist
2. b) Bereitstellung eines Reflexionselements umfassend eine optisch hochbrechende Dünnglasscheibe mit einer außenseitigen Oberfläche, einer innenraumseitigen Oberfläche, einer Dicke von 20 µm bis 500 µm und einem Brechungsindex von größer oder gleich 1,9 und einer auf der innenraumseitigen Oberfläche der optisch hochbrechenden Dünnglasscheibe aufgetragenen optisch niedrigbrechenden Schicht mit einem Brechungsindex von kleiner oder gleich 1,6;
3. c) Verbinden der außenseitigen Oberfläche der optisch hochbrechenden Dünnglasscheibe mit der innenraumseitigen Oberfläche der Innenscheibe des Verbunds über eine Klebeschicht zu einer Verbundscheibe, derart, dass das Reflexionselement in einem Bereich der Verbundscheibe angeordnet ist, der bei senkrechter Durchsicht durch die Verbundscheibe vollständig in dem Bereich liegt, in dem die Maskierungsschicht angeordnet ist.

A composite pane according to the invention can be produced by a process comprising at least:

1. a) Providing a composite comprising an outer pane with an outer surface and an interior surface, a thermoplastic intermediate layer and an inner pane with an outer surface and an interior surface, wherein the thermoplastic intermediate layer is arranged between the outer pane and the inner pane and a masking layer is arranged between the outer pane and the inner pane or on the interior surface of the inner pane in an area
2. b) providing a reflection element comprising an optically highly refractive thin glass pane with an outside surface, an inside surface, a thickness of 20 µm to 500 µm and a refractive index of greater than or equal to 1.9 and an optically low-refractive layer with a refractive index of less than or equal to 1.6 applied to the inside surface of the optically highly refractive thin glass pane;
3. c) connecting the outside surface of the optically highly refractive thin glass pane to the inside surface of the inner pane of the composite via an adhesive layer to form a composite pane, such that the reflection element is arranged in a region of the composite pane which, when viewed perpendicularly through the composite pane, lies entirely in the region in which the masking layer is arranged.

Steps a) and b) can be carried out in the order given, simultaneously or in reverse order. Step c) is preferably carried out after steps a) and b), but can also be carried out simultaneously with steps a) and b).

As explained above, the reflection element is arranged in an area of the composite pane which, when viewed perpendicularly through the composite pane, lies entirely in the area in which the masking layer is arranged. Thus, the reflection element is smaller in terms of its external dimensions than the outer pane and the inner pane of the composite pane. The provision of the reflection element in step b) can be carried out by applying an optically low-refractive layer with a refractive index of less than or equal to 1.6 to the entire interior surface of an optically high-refractive thin glass pane with a thickness of 20 µm to 500 µm, a refractive index of greater than or equal to 1.9 and with the desired dimensions.

Alternatively, the provision of the reflection element in step b) can also be carried out by applying an optically low-refractive layer with a refractive index of less than or equal to 1.6 to the entire interior surface of an optically high-refractive thin glass pane with a thickness of 20 µm to 500 µm and a refractive index of greater than or equal to 1.9, which is larger than desired in terms of external dimensions, i.e. width and length, and then cutting out a section from such a coated thin glass pane, for example by means of a laser cutting process, which has the desired dimensions.

If the composite pane is to be curved, a curved outer pane and a curved inner pane are used when preparing the composite in step a). The reflection element is flexible due to the low thickness of the optically highly refractive thin glass pane and adapts to the curved inner pane of the composite in step c). This is an advantage of the process.

The provision of the composite in step a) can be carried out by means of lamination processes familiar to the person skilled in the art.

When providing the reflection element in step b), the application of the optically low-refractive layer can be carried out by means of generally known coating methods, such as magnetron sputtering or wet coating.

The preferred embodiments of the composite pane according to the invention described above also apply accordingly to methods for producing a composite pane according to the invention.

A composite pane according to the invention can be used as a vehicle pane in means of transport for traffic on land, in the air or on water, in particular in motor vehicles and in particular as a windshield for a head-up display.

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

• 1 eine Draufsicht auf eine Ausführungsform einer erfindungsgemäßen Verbundscheibe,
• 2 einen Querschnitt durch die in der 1 gezeigte Ausführungsform,
• 3 einen Querschnitt durch eine weitere Ausführungsform einer erfindungsgemäßen Verbundscheibe,
• 4 einen Querschnitt durch eine weitere Ausführungsform einer erfindungsgemäßen Verbundscheibe,
• 5 einen Querschnitt durch eine weitere Ausführungsform einer erfindungsgemäßen Verbundscheibe,
• 6 eine Draufsicht auf eine weitere Ausführungsform einer erfindungsgemäßen Verbundscheibe,
• 7 einen Querschnitt durch die in der 6 gezeigte Ausführungsform,
• 8 einen Querschnitt durch eine weitere Ausführungsform einer erfindungsgemäßen Verbundscheibe,
• 9 einen Querschnitt durch eine weitere Ausführungsform einer erfindungsgemäßen Verbundscheibe,
• 10 einen Querschnitt durch eine weitere Ausführungsform einer erfindungsgemäßen Verbundscheibe,
• 11 einen Querschnitt durch eine weitere Ausführungsform einer erfindungsgemäßen Verbundscheibe,
• 12 einen Querschnitt durch eine Ausführungsform einer erfindungsgemäßen Projektionsanordnung,
• 13 einen Querschnitt durch eine weitere Ausführungsform einer erfindungsgemäßen Projektionsanordnung,
• 14 ein Ausführungsbeispiel eines Verfahrens anhand eines Flussdiagramms,
• 15 Reflexionsspektren von Verbundscheiben gegenüber p-polarisierter Strahlung unter einem Einstrahlwinkel von 60°,
• 16 Reflexionsspektren von Verbundscheiben gegenüber p-polarisierter Strahlung unter einem Einstrahlwinkel von 65°,
• 17 Reflexionsspektren von Verbundscheiben gegenüber p-polarisierter Strahlung unter einem Einstrahlwinkel von 70°,
• 18 Reflexionsspektren von Verbundscheiben gegenüber p-polarisierter Strahlung unter einem Einstrahlwinkel von 75°.

They show:

• 1 a plan view of an embodiment of a composite pane according to the invention,
• 2 a cross-section of the 1 shown embodiment,
• 3 a cross section through another embodiment of a composite pane according to the invention,
• 4 a cross section through another embodiment of a composite pane according to the invention,
• 5 a cross section through another embodiment of a composite pane according to the invention,
• 6 a plan view of another embodiment of a composite pane according to the invention,
• 7 a cross-section of the 6 shown embodiment,
• 8 a cross section through another embodiment of a composite pane according to the invention,
• 9 a cross section through another embodiment of a composite pane according to the invention,
• 10 a cross section through another embodiment of a composite pane according to the invention,
• 11 a cross section through another embodiment of a composite pane according to the invention,
• 12 a cross section through an embodiment of a projection arrangement according to the invention,
• 13 a cross section through a further embodiment of a projection arrangement according to the invention,
• 14 an embodiment of a method using a flow chart,
• 15 Reflection spectra of composite panes against p-polarized radiation at an incident angle of 60°,
• 16 Reflection spectra of composite panes against p-polarized radiation at an incident angle of 65°,
• 17 Reflection spectra of composite panes against p-polarized radiation at an incident angle of 70°,
• 18 Reflection spectra of composite panes against p-polarized radiation at an incident angle of 75°.

1 shows a plan view of an embodiment of a composite pane 100 according to the invention and in 2 is the cross section through the 1 The composite pane 100 shown in the drawing is shown along the section line XX`. 1 and 2 The composite pane 100 shown has an upper edge O, a lower edge U and two side edges S and comprises an outer pane 1 with an outside surface I and an inside surface II, an inner pane 2 with an outside surface III and an inside surface IV, a thermoplastic intermediate layer 3, a masking layer 4, an adhesive layer 5 and a reflection element 6 comprising an optically high-refractive thin glass pane 7 with an outside surface V and an inside surface VI and an optically low-refractive layer 8. The thermoplastic intermediate layer 3 is arranged between the outer pane 1 and the inner pane 2, the inner pane 2 is arranged between the outer pane 1 and the reflection element 6 and the adhesive layer 5 is arranged between the inner pane 2 and the reflection element 6. The outer pane 1, the thermoplastic intermediate layer 3 and the inner pane 2 are arranged one above the other over their entire surface. The masking layer 4 is arranged between the outer pane 1 and the inner pane 2 in a region of the composite pane 100. In the 1 and 2 In the embodiment shown, the masking layer 4 is applied as a layer on the interior surface II of the outer pane 1. arranged opaque cover print and arranged only in an edge region of the composite pane 100 bordering the lower edge U. The reflection element 6 is arranged in an area of the composite pane 100 which, when viewed vertically through the composite pane 100, lies entirely in the area in which the masking layer 4 is arranged. The reflection element 6 is thus smaller in terms of its external dimensions than the inner pane 2. The outside surface V of the optically highly refractive thin glass pane 7 is connected to the interior surface IV of the inner pane 2 via the adhesive layer 5. The optically low refractive layer 8 is arranged on the interior surface VI of the optically highly refractive thin glass pane 7.

The optically high-refractive thin glass pane 7 has, for example, a refractive index of 2.3 and a thickness of 100 µm. The thermoplastic intermediate layer 3 contains, for example, PVB and has a thickness of 0.76 mm. The outer pane 1 consists, for example, of soda-lime glass and is 2.1 mm thick. The inner pane 2 consists, for example, of soda-lime glass and is 1.6 mm thick. The adhesive layer 5 is, for example, an optically clear adhesive. The optically low-refractive layer 8 is, for example, an SiO ₂ layer with a thickness of 120 nm and a refractive index of 1.45.

In the in the 1 and 2 In the embodiment shown, the masking layer 4 extends between the two side edges S of the composite pane 100 and, starting from the lower edge U of the composite pane 100, has a width of, for example, 30 cm.

It is understood that the composite disc 100 may have any suitable geometric shape and/or curvature. Typically, the composite disc 100 is a curved composite disc.

3 shows a cross section through another embodiment of a composite pane 100 according to the invention. The 3 The embodiment shown in cross section differs from that shown in the 2 shown only in that the masking layer 4 is not designed as an opaque cover print arranged on the interior-side surface II of the outer pane 1, but as an opaque cover print arranged on the exterior-side surface III of the inner pane 2.

4 shows a cross section through another embodiment of a composite pane 100 according to the invention. The 4 The embodiment shown in cross section differs from that shown in the 2 shown only in that the masking layer 4 is not designed as an opaque cover print arranged on the interior-side surface II of the outer pane 1, but is designed as an opaque-colored region of the thermoplastic intermediate layer 3.

5 shows a cross section through another embodiment of a composite pane 100 according to the invention. The 5 The embodiment shown in cross section differs from that shown in the 2 shown only in that the masking layer 4 is not designed as an opaque cover print arranged on the interior-side surface II of the outer pane 1, but rather as an opaque cover print arranged on the interior-side surface IV of the inner pane 2. It is understood that in this embodiment the adhesive layer 5 is not arranged directly adjacent to the interior-side surface IV of the inner pane 2, but is arranged directly adjacent to the masking layer 4 arranged on the interior-side surface IV of the inner pane 2.

6 shows a plan view of another embodiment of a composite pane 100 according to the invention and in 7 is the cross section through the 6 The composite pane 100 shown in the drawing is shown along the section line YY`. 6 and 7 The composite pane 100 shown has an upper edge O, a lower edge U and two side edges S and comprises an outer pane 1 with an outside surface I and an inside surface II, an inner pane 2 with an outside surface III and an inside surface IV, a thermoplastic intermediate layer 3, a masking layer 4, an adhesive layer 5 and a reflection element 6 comprising an optically high-refractive thin glass pane 7 with an outside surface V and an inside surface VI and an optically low-refractive layer 8. The thermoplastic intermediate layer 3 is arranged between the outer pane 1 and the inner pane 2, the inner pane 2 is arranged between the outer pane 1 and the reflection element 6 and the adhesive layer 5 is arranged between the inner pane 2 and the reflection element 6. The outer pane 1, the thermoplastic intermediate layer 3 and the inner pane 2 are arranged one above the other over their entire surface. The masking layer 4 is arranged between the outer pane 1 and the inner pane 2 in a region of the composite pane 100. The region in which the masking layer 4 is arranged is provided with the reference symbol A. In the 6 and 7 In the embodiment shown, the masking layer 4 is provided as a layer on the interior surface II of the outer pane 1 and arranged in a peripheral edge region which has a greater width in a section which overlaps the reflection element 6 than in sections which are different from it. For simplified illustration, the masking layer in the 6 not black, but patterned. The reflection element 6 is arranged in an area of the composite pane 100 which, when viewed vertically through the composite pane 100, lies entirely in the area in which the masking layer 4 is arranged and in which 6 is provided with the reference symbol B. The reflection element 6 is thus smaller in terms of its external dimensions than the inner pane 2. The outer surface V of the optically highly refractive thin glass pane 7 is connected to the interior surface IV of the inner pane 2 via the adhesive layer 5. An optically low-refractive layer 8 is arranged on the interior surface VI of the optically highly refractive thin glass pane 7.

The optically highly refractive thin glass pane 7 has, for example, a refractive index of 2.3 and a thickness of 100 µm. The thermoplastic intermediate layer 3 contains, for example, PVB and has a thickness of 0.76 mm. The outer pane 1 consists, for example, of soda-lime glass and is 2.1 mm thick. The inner pane 2 consists, for example, of soda-lime glass and is 1.6 mm thick.

The adhesive layer 5, for example, is an optically clear adhesive.

The optically low-refractive layer 8 is, for example, a nanoporous SiO ₂ layer with a thickness of 150 nm and a refractive index of 1.3.

It is understood that the composite disc 100 may have any suitable geometric shape and/or curvature. Typically, the composite disc 100 is a curved composite disc.

8 shows a cross section through another embodiment of a composite pane 100 according to the invention. The 8 The embodiment shown in cross section differs from that shown in the 7 shown only in that the masking layer 4 is not designed as an opaque cover print arranged on the interior-side surface II of the outer pane 1, but as an opaque cover print arranged on the exterior-side surface III of the inner pane 2.

9 shows a cross section through another embodiment of a composite pane 100 according to the invention. The 9 The embodiment shown in cross section differs from that shown in the 7 shown only in that the masking layer 4 is not designed as an opaque cover print arranged on the interior-side surface II of the outer pane 1, but is designed as an opaque-colored region of the thermoplastic intermediate layer 3.

10 shows a cross section through another embodiment of a composite pane 100 according to the invention. The 10 The embodiment shown in cross section differs from that shown in the 7 shown only in that the masking layer 4 is not designed as an opaque cover print arranged on the interior-side surface II of the outer pane 1, but rather as an opaque cover print arranged on the interior-side surface IV of the inner pane 2. It is understood that in this embodiment the adhesive layer 5 is not arranged directly adjacent to the interior-side surface IV of the inner pane 2, but is arranged directly adjacent to the masking layer 4 arranged on the interior-side surface IV of the inner pane 2.

11 shows a cross section through another embodiment of a composite pane 100 according to the invention. The 11 The embodiment shown in cross section differs from that shown in the 2 shown only in that the composite pane 100 additionally has a HUD reflection layer 9 arranged between the inner pane 2 and the thermoplastic intermediate layer 3. The HUD reflection layer 9 also extends into the see-through area of the composite pane 100, i.e. the area in which no masking layer 4 is present. The HUD reflection layer 9 is designed as a layer that reflects p-polarized light.

12 shows a cross section through an embodiment of a projection arrangement 101 according to the invention. The 12 The projection arrangement 101 shown comprises a composite pane 100 and an imaging unit 10. In the 12 In the embodiment of a projection arrangement according to the invention shown, the composite pane 100 is as shown in the 2 shown, whereby the optically high-refractive thin glass pane 7 and the optically low-refractive layer 8 of the reflection element 6 are not shown separately. It is understood that the composite pane can alternatively also be designed as in the 3 , 4 , 5 , 7 , 8 , 9 , 10 or 11 can be designed. The projection arrangement 101 has an imaging unit 10. The imaging unit 10 serves to generate p-polarized light (image information) which is directed onto the reflection element 6 and is reflected by the reflection element 6 as reflected light into the vehicle interior, where it can be perceived by an observer, e.g. the driver. The light preferably strikes the reflection element at an angle of incidence of 55° to 80°, in particular of 62° to 77°. The imaging unit 10 is, for example, a display, in particular an LCD display.

13 shows a cross section through another embodiment of a projection arrangement 101 according to the invention. The 13 The embodiment shown differs from that in the 12 shown only in that the composite pane 100 additionally has a HUD reflection layer 9 arranged between the inner pane 2 and the thermoplastic intermediate layer 3. The HUD reflection layer 9 is designed as a layer that reflects p-polarized light. The HUD reflection layer 9 also extends into the see-through area of the composite pane 100, i.e. the area in which there is no masking layer 4. A projector (not shown) that emits p-polarized light can be aimed at this area of the pane and the HUD reflection layer 9 can be used as a projection surface for a virtual image. The image projected by the imaging unit 10 onto the reflection element 6 is clearly visible against the background of the marking layer 4 with high contrast. The HUD reflection layer 9 can be used independently of the reflection element 6, whereby the image reflected by the reflection element 6 and the HUD image do not influence each other.

In 14 an embodiment of a method for producing a composite pane according to the invention is shown using a flow chart.

In a first step S1, a composite is provided comprising an outer pane 1 with an outer surface I and an interior surface II, a thermoplastic intermediate layer 3 and an inner pane 2 with an outer surface III and an interior surface IV, wherein the thermoplastic intermediate layer 3 is arranged between the outer pane 1 and the inner pane 2 and a masking layer 4 is arranged between the outer pane 1 and the inner pane 2 or on the interior surface IV of the inner pane 2 in an area.

In a second step S2, a reflection element 6 comprising an optically highly refractive thin glass pane 7 with an outside surface V, an inside surface VI, a thickness of 20 µm to 500 µm and a refractive index of greater than or equal to 1.9 and an optically low-refractive layer 8 with a refractive index of less than or equal to 1.6 applied to the inside surface VI of the optically highly refractive thin glass pane 7 is provided.

In a third step S3, the outside surface V of the optically highly refractive thin glass pane 7 of the reflection element 6 is connected to the inside surface IV of the inner pane 2 of the composite via an adhesive layer 5 to form a composite pane 100, such that the reflection element 6 is arranged in a region of the composite pane 100 which, when viewed perpendicularly through the composite pane 100, lies entirely in the region in which the masking layer 4 is arranged.

Steps S1 and S2 can also be carried out in reverse order or simultaneously. Step S3 preferably takes place after steps S1 and S2, but can also take place simultaneously with steps S1 and S2.

The invention is explained below using examples and comparative examples. The reflection properties for p-polarized light of composite panes according to the invention and composite panes not according to the invention are compared below.

The layer sequence, the layer thicknesses and the refractive indices according to Comparative Examples C and D and inventive Examples E, F, G, H and J are given in Tables 1 and 2.

In order to simulate a masking layer, a dark outer pane 1 and dark PVB as a thermoplastic intermediate layer 3 were used in comparative examples C and D and inventive examples E, F, G, H and J. Table 1 material Comparison example C Comparison example D0 fingerprint - 20.0nm n = 1.4 _SiO2 130.0nm 130.0nm n = 1.45 n = 1.45 _TiO2 60.0nm 60.0nm n = 2.45 n = 2.45 Soda-lime glass 2.1mm 2.1mm PVB (tinted) 0.76mm 0.76mm Soda-lime glass (tinted) 2.1mm 2.1mm Table 2 material Example E Example F Example G Example H Example J fingerprint - 20.0nm 20.0nm n = 1.4 n = 1.4 _SiO2 120.0nm 120.0nm 130.0nm 110.0nm 110.0nm n = 1.45 n = 1.45 n = 1.3 n = 1.45 n = 1.45 Thin glass pane 100 µm 100 µm 100 µm 100 µm 100 µm n = 2.3 n = 2.3 n = 2.3 n = 2.1 n = 2.1 Soda-lime glass 2.1mm 2.1mm 2.1mm 2.1mm 2.1mm PVB (tinted) 0.76mm 0.76mm 0.76mm 0.76mm 0.76mm Soda-lime glass (tinted) 2.1mm 2.1mm 2.1mm 2.1mm 2.1mm

In example G, the SiO ₂ used is nanoporous SiO ₂ .

The reflection factor for p-polarized light, which is essential for image quality, is referred to as RL(A) p-pol. The reflection factor describes the proportion of the total p-polarized radiation that is reflected. It is given as a unitless number from 0 to 1 (normalized to the radiation that is radiated). Plotted as a function of the wavelength, it forms the reflection spectrum. The information on the reflection factor refers to a reflection measurement with a light source of light type A, which radiates in the spectral range from 380 nm to 780 nm with a normalized radiation intensity of 1. The corresponding reflection spectra of the comparison examples and examples at angles of incidence of 60°, 65°, 70° and 75° are shown in 15 to 18 shown.

As can be seen from the 15 to 18 As can be seen, the reflection spectrum of comparative example D is clearly shifted towards higher wavelengths compared to the reflection spectrum of comparative example C due to the fingerprint acting as an additional interference layer. The image quality of a composite pane according to comparative example D is therefore significantly reduced compared to the image quality of a composite pane according to comparative example C. The reflection spectrum of example F, on the other hand, is less shifted towards higher wavelengths compared to the reflection spectrum of example E than is the case with comparative examples C and D. Likewise, the reflection spectrum of example J is less shifted towards higher wavelengths compared to the reflection spectrum of example H than is the case with comparative examples C and D. Thus, a fingerprint on the reflection element of a composite pane according to the invention causes a smaller change in the reflection spectrum than a fingerprint on the reflection layer of a composite pane according to comparative example C comprising an optically high-refractive coating and an optically low-refractive coating. Fingerprints are therefore less visible on the composite panes according to the invention. This is an advantage of the inventive appropriate composite panes. From the 15 to 18 It is also clear that in examples E, F, G, H and J the absolute reflection intensity is lower, but the reflection spectrum is smoother than in comparative examples C and D. The wavelength dependence of the degree of reflection is less pronounced in examples E, F, G, H and J, which is advantageous for the color neutrality of a reflected image. The composite panes according to examples E, F, G, H and J therefore show a particularly homogeneous reflection spectrum. This is a further advantage of the composite panes according to the invention.

List of reference symbols:

100

Composite pane

101

Projection arrangement

1

Outer pane

2

Inner pane

3

thermoplastic intermediate layer

4

Masking layer

5

Adhesive layer

6

Reflection element

7

optically highly refractive thin glass pane

8

optically low refractive layer

9

HUD reflective layer

10

imaging unit

O

Upper edge of the composite pane 100

U

Lower edge of the composite pane 100

S

Side edge of the composite pane 100

I

outside surface of the outer pane 1

II

interior surface of the outer pane 1

III

outside surface of the inner pane 2

IV

interior surface of the inner pane 2

V

outside surface of the optically highly refractive thin glass pane 7

VI

interior surface of the optically highly refractive thin glass pane 7

A

Area in which the masking layer 4 is arranged

B

Area in which the reflection element 6 is arranged

X`-X

Cutting line

Y-Y'

Cutting line

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions.

Cited patent literature

• DE 102014220189 A1 [0003]
• US 20040135742 A1 [0003]
• WO 9619347 A3 [0003]
• WO 2021122848 A1 [0004]
• WO 2021145387 A1 [0005]
• CN114035322A [0006]
• US 20200333593 A1 [0007]
• JP 2016097781 A [0008]
• WO 2022073894 A1 [0011]
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• DE 102009020824 A1 [0013]
• DE 112011104339 B4 [0066]
• DE 102020120171 A1 [0066]
• WO 2019131123 A1 [0066]

Claims (13)

Composite pane (100), comprising at least - an outer pane (1) with an outer surface (I) and an interior surface (II), - a thermoplastic intermediate layer (3), - an inner pane (2) with an outer surface (III) and an interior surface (IV), - a masking layer (4), - an adhesive layer (5), - a reflection element (6) comprising an optically high-refractive thin glass pane (7) with an outer surface (V), an interior surface (VI), a thickness of 20 µm to 500 µm and a refractive index greater than or equal to 1.9 and an optically low-refractive layer (8) arranged on the interior surface (VI) of the optically high-refractive thin glass pane (7) with a refractive index of less than or equal to 1.6, wherein the thermoplastic intermediate layer (3) is arranged between the outer pane (1) and the inner pane (2), the masking layer (4) is arranged between the outer pane (1) and the inner pane (2) or on the interior-side surface (IV) of the inner pane (2) in an area of the composite pane (100), the adhesive layer (5) is arranged between the inner pane (2) and the reflection element (6), the outer surface (V) of the optically highly refractive thin glass pane (7) is connected to the interior-side surface (IV) of the inner pane (2) via the adhesive layer (5), and the reflection element (6) is arranged in an area of the composite pane (100) which, when viewed perpendicularly through the composite pane (100), lies entirely in the area in which the masking layer (4) is arranged. Composite pane (100) after Claim 1 , wherein the optically highly refractive thin glass pane (7) has a thickness of 50 µm to 300 µm, preferably 50 µm to 200 µm. Composite pane (100) after Claim 1 or 2 , wherein the refractive index of the optically highly refractive thin glass pane (7) is at least 2.0, preferably at least 2.1, particularly preferably at least 2.3. Composite pane (100) according to one of the Claims 1 until 3 , wherein the optically highly refractive thin glass disc (7) contains doping with lead, barium or lanthanum. Composite pane (100) according to one of the Claims 1 until 4 , wherein the refractive index of the optically low-refractive layer (8) is at most 1.5, preferably at most 1.4. Composite pane (100) according to one of the Claims 1 until 5 , wherein the optically low-refractive layer (8) is based on silicon dioxide, doped silicon oxide, magnesium fluoride or calcium fluoride. Composite pane (100) according to one of the Claims 1 until 6 , wherein the optically low-refractive layer (8) has a thickness of 50 nm to 200 nm, preferably 100 nm to 150 nm, in particular 120 nm. Composite pane (100) according to one of the Claims 1 until 7 in which the masking layer (4) is formed in a frame-like manner and has a greater width in particular in a section which overlaps the reflection element (6) than in sections different therefrom. Composite pane (100) according to one of the Claims 1 until 8 , wherein the masking layer (4) is formed as an opaque cover print arranged on the interior-side surface (II) of the outer pane (1), the exterior-side surface (III) of the inner pane (2) or the interior-side surface (IV) of the inner pane (2) or as an opaquely colored region of the thermoplastic intermediate layer (3). Composite pane (100) according to one of the Claims 1 until 9 , wherein a HUD reflection layer (9) is arranged between the outer pane (1) and the inner pane (2). Projection arrangement (101) comprising at least - a composite pane (100) according to one of the Claims 1 until 10 , - an imaging unit (10) directed at the reflection element (6) which emits p-polarized light, wherein the interior-side surface (IV) of the inner pane (2) is the surface of the inner pane (2) closest to the imaging unit (10). Projection arrangement (101) according to Claim 11 , wherein the reflection element (6) reflects at least 3%, preferably at least 4%, particularly preferably at least 6%, very particularly preferably at least 10% of the p-polarized light incident on the reflection element (6) in a wavelength range from 400 nm to 700 nm and angles of incidence from 62° to 77°. Projection arrangement (101) according to Claim 11 or 12 , wherein the imaging unit (10) is a display, preferably an LCD display, LED display, OLED display or electroluminescent display, particularly preferably an LCD display, and the p-polarized light (7) preferably strikes the composite pane (10) at an angle of incidence of 55° to 80°, particularly preferably of 62° to 77°.

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