CN117460620A

CN117460620A - Composite glass pane with reflective element

Info

Publication number: CN117460620A
Application number: CN202380010460.XA
Authority: CN
Inventors: J·哈根; A·戈默
Original assignee: Saint Gobain Glass France SAS
Current assignee: Saint Gobain Glass France SAS
Priority date: 2022-05-25
Filing date: 2023-05-23
Publication date: 2024-01-26
Also published as: WO2023227595A1

Abstract

The invention relates to a composite glass pane (100) comprising at least an outer glass pane (1) having an outer side surface (I) and an inner side surface (II), a thermoplastic interlayer (3), an inner glass pane (2) having an outer side surface (III) and an inner side surface (IV), a masking layer (4), an adhesive layer (5), comprising an optically high refractive thin glass pane (7) having an outer side surface (V), an inner side surface (VI), a thickness of 20 μm to 500vm and a refractive index of 1.9 or more, and a reflective element (6) arranged on the inner side surface (VI) having an optically low refractive layer (8) having a refractive index of 1.6 or less, wherein the thermoplastic interlayer (3) is arranged between the outer glass pane (1) and the inner glass pane (2), the masking layer (4) is arranged between the outer glass pane (1) and the inner glass pane (2) or on the inner side surface (IV) of the inner glass pane (2) in one region of the composite glass pane (100), the adhesive layer (5) is arranged between the inner glass pane (2) and the reflective element (6) and the reflective element (8) on the inner side surface (V) of the inner glass pane (5), and the reflective element (6) is arranged in a region of the composite glass sheet (100) which, when viewed perpendicularly through the composite glass sheet (100), is located entirely in the region in which the masking layer (4) is arranged.

Description

Composite glass pane with reflective element

The invention relates to a composite glass pane with a zone-arranged reflective element, to a method for the production thereof and to the use thereof, and to a projection assembly.

What is commonly used to display navigation data in windshields is a projection assembly known under the term "head-up display (HUD)", which consists of an image display device and a windshield with a wedge-shaped thermoplastic interlayer and/or a wedge-shaped glass plate. The wedge angle is necessary here to avoid ghosting. The projected image appears in the form of a virtual image at a distance from the windscreen such that the driver of the mobile vehicle perceives the projected navigation data, for example in the form of the projected navigation data being located on a road in front of him. Because windshields have better reflection characteristics than p-polarization, the radiation from HUD image display devices is typically substantially s-polarized. However, if the viewer wears polarization-selective sunglasses that do not transmit s-polarized light, the HUD image is perceived as weaker. One solution to this problem is to use a projection assembly that utilizes p-polarized light.

DE 102014220189A1 discloses a head-up display projection assembly operating with p-polarized radiation, wherein the windscreen has a reflective structure reflecting the p-polarized radiation in the direction of the viewer. US20040135742 A1 also discloses a heads-up display projection assembly with reflective structure using p-polarized radiation. In WO 96/19347A3, a plurality of polymer layers is proposed as reflective structures.

WO 2021/122848A1 discloses a HUD system comprising a light source protecting p-polarized light towards a glazing, wherein the glazing comprises an outer glass sheet having a first surface and a second surface, and an inner glass sheet having a first surface and a second surface, wherein the second surface of the inner glass sheet comprises a reflective coating, the two glass sheets being joined by at least one interlayer material, the reflective coating comprising at least one high refractive layer having a thickness of 50 to 100nm and at least one low refractive layer having a thickness of 70 to 160nm, wherein at least one high refractive layer comprises oxides of Zr, nb, sn; ti, zr, nb, si, sb, sn, zn, in mixed oxides; nitrides of Si, zr; and at least one of mixed nitrides of Si and Zr.

WO 2021/145387A1 discloses a HUD system in which a composite glass sheet is regionally provided with reflective elements for p-polarized light. The reflective element may be a p-polarized light reflective film adhered to the inner side surface of the inner glass sheet by means of an adhesion promoter layer or a p-polarized light reflective coating layer arranged on the inner side surface of the inner glass sheet, wherein the reflective coating layer has at least one layer of a material having a high refractive index and at least one layer of a material having a low refractive index.

CN 114035322a discloses a head-up display glass comprising a laminated glass, wherein the laminated glass comprises a first surface and a second surface opposite to each other, the second surface comprising a display area and a non-display area, wherein the display area is provided with a first nanomembrane having at least one high refractive layer and at least one low refractive layer sequentially laminated outwards from the second surface, wherein the refractive index of the first high refractive layer is 1.9 to 2.7 and the refractive index of the first low refractive layer is 1.3 to 1.8.

US2020/0333593A1 discloses a composite glass sheet for a HUD system having a first nanostructured coating on an outer side surface of an outer glass sheet, a second nanostructured coating on an inner side surface of an inner glass sheet, and a reflective coating between the inner side surface of the inner glass sheet and the second nanostructured coating.

JP 2016097781a discloses a HUD system comprising a windshield, a low reflection layer formed on the inner side of the windshield, and a hardened layer formed on the outer side of the windshield, wherein a transparent hardened film having a refractive index of 2.0 or more and a glass having a high refractive index can be used as the hardened layer.

Reflective coatings applied to the inside of the composite glass sheet can have the disadvantage that they have low color neutrality of the image reflected by the reflective coating, and fingerprints or contaminants on the reflective coating can cause the reflected spectrum to shift significantly to higher wavelengths.

When designing displays based on heads-up display technology, further care must be taken to ensure that the image display device has a correspondingly high power so that the projected image has sufficient brightness, in particular in the case of incident sunlight, and is easily recognizable by a viewer. This requires a certain size of the image display device and is associated with a corresponding power consumption.

WO 2022/073894A1 discloses a carrier glass plate for a head-up display, having an outer face facing the external environment in the mounted state and an inner face facing the interior of the carrier, comprising at least one transparent glass plate, at least one masking strip in the edge region of the glass plate, and at least one reflective layer applied in a printing method for reflecting light relative to the masking strip towards the interior of the carrier, the reflective layer being arranged in the region of the masking strip.

WO 2022/073860A1 discloses a carrier glass plate for a head-up display having an outer face which in the mounted state faces the external environment and an inner face which faces the interior of the carrier, comprising at least one transparent glass plate, at least one masking strip in the edge region of the glass plate, and at least one light deflecting device for deflecting light into the interior of the carrier, or at least one image display device for displaying image information relative to the masking strip towards the interior of the carrier, the image display device being arranged in the region of the masking strip.

DE 1 02009020824a 1 discloses a virtual image system for a windscreen, which is capable of reflecting from an image source on the windscreen, so that the driver can see a virtual image without ghost images. Either a matte black material is applied to the windshield on any of the windshield surfaces of the outer glass sheet, or to the windshield surface of the inner glass sheet, or a black gloss layer is arranged on the windshield surface on the windshield frit, thereby delivering a virtual image for any image source with real image light incident on the windshield surface.

It is an object of the present invention to provide an improved composite glass sheet with a reflective element, a method for its production, its use, and an improved projection assembly comprising such a composite glass sheet.

According to the invention, the object of the invention is achieved by a composite glass sheet, a projection assembly, a method and a use according to the appended claims. Preferred embodiments are evident from the dependent claims.

The composite glass sheet according to the present invention includes an outer glass sheet, a thermoplastic interlayer, a masking layer, an inner glass sheet, an adhesive layer, and a reflective element. The thermoplastic interlayer is disposed between the outer and inner glass sheets, and the adhesive layer is disposed between the inner glass sheet and the reflective element. According to the invention, the masking layer is arranged in one region of the composite glass pane and the reflective element is arranged in one region of the composite glass pane, which region is located entirely in the region in which the masking layer is arranged when viewed perpendicularly through the composite glass pane.

The reflective element includes an optically high refractive thin glass plate and an optically low refractive layer. The optically high refractive thin glass sheet 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 optically high refractive thin glass sheet is greater than or equal to 1.9. The optical low refractive layer has a refractive index of at most 1.6, i.e. the refractive index of the optical low refractive layer is less than or equal to 1.6.

A composite glass pane is provided in a window of the carrier to separate the interior from the exterior environment. In the context of the present invention, an "inner glass sheet" refers to a glass sheet where the composite glass sheet faces the interior of the carrier. "outer glass sheet" refers to a glass sheet that faces the outside environment.

The composite glass sheet has in particular an upper edge and a lower edge and two side edges extending therebetween. "upper edge" refers to the edge that is intended to be directed upwards in the installed position. "lower edge" refers to an edge that is intended to be directed downward in the installed position. In the case of windshields, the upper edge is commonly referred to as the "top edge"; the lower edge is referred to as the "engine edge".

The outer glass pane, the inner glass pane and the optically high-refractive thin glass pane have in each case an outer and an inner surface and a circumferential side edge extending between them. In the context of the present invention, "outer side surface" refers to the main surface intended to face the external environment in the mounted position. In the context of the present invention, an "inside surface" refers to a main surface intended to face inwards in the mounted position. The inner side surface of the outer layer glass sheet and the outer side surface of the inner layer glass sheet face each other and are bonded to each other by the thermoplastic interlayer. The inner side surface of the inner layer glass plate and the outer side surface of the optical high refractive thin glass plate face each other and are bonded to each other by an adhesive layer.

According to the present invention, an optical low refractive layer is disposed on the inner side surface of an optical high refractive thin glass plate. The optical low refractive layer is thus implemented as a full surface coating of the inner side surface of the optical high refractive thin glass plate.

The outer surface of the outer glass sheet is referred to as face I. The inner side surface of the outer glass sheet is referred to as face II. The outer surface of the inner glass sheet is referred to as face III. The inner surface of the inner glass sheet is referred to as face IV. The outer surface of the optically high refractive thin glass plate is referred to as the face V. The inside surface of the optically high refractive thin glass sheet is referred to as face VI.

Needless to say, the inner glass plate is arranged between the outer glass plate and the optical high refractive thin glass plate.

The outer side surface of the optically high refractive thin glass plate is bonded to the inner side surface of the inner glass plate via an adhesive layer

The inner side surface of the inner glass sheet is the surface of the inner glass sheet closest to the reflective element.

The masking layer is disposed between the outer and inner glass sheets or on the inside surface of the inner glass sheet. Thus, in the mounted state of the composite glass sheet in the carrier, the reflective element is closer to the interior of the carrier than the opaque masking layer.

As described above, the outer side surface of the optically high refractive thin glass plate is bonded to the inner side surface of the inner glass plate via the adhesive layer. Needless to say, in embodiments in which the masking layer is disposed on the inner side surface of the inner layer glass plate, the outer side surface of the optically high refractive thin glass plate is not directly bonded to the inner side surface of the inner layer glass plate via the adhesive layer, but is indirectly bonded because in these embodiments, the masking layer disposed on the inner side surface of the inner layer glass plate is disposed between the adhesive layer and the inner side surface of the inner layer glass plate.

As described above, the optically high refractive thin glass plate has a thickness of 20 μm (micrometers) to 500 μm. The optically high refractive thin glass sheet is thus a glass sheet of ultra thin glass. The glass sheet of such ultra thin glass is flexible and can conform to the curvature of the glass sheet.

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

The refractive index of the optically high-refractive thin glass sheet 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 high refractive thin glass sheet is preferably at most 2.4.

In a preferred embodiment of the composite glass sheet according to the invention, the optical high refractive thin glass sheet has a refractive index of 1.9 to 2.4. In another preferred embodiment of the composite glass sheet according to the invention, the optical high refractive thin glass sheet has a refractive index of 2.0 to 2.4. In another preferred embodiment of the composite glass sheet according to the invention, the optical high refractive thin glass sheet has a refractive index of 2.1 to 2.4. In another preferred embodiment of the composite glass sheet according to the invention, the optical high refractive thin glass sheet has a refractive index of 2.3 to 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 optical low refractive layer is 1.2 to 1.5. The refractive index of the optical low refractive layer is, for example, 1.3 or 1.45. These values have proven to be particularly advantageous in terms of the reflective properties of the glass sheet.

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

In the context of the present invention, the refractive index is in principle indicated on the basis of a wavelength of 550 nm. Methods for determining the refractive index are known to those skilled in the art. The refractive index indicated in the context of the present invention may be determined, for example, by ellipsometry using a commercially available ellipsometer. Unless otherwise indicated, the layer thickness or indication of thickness is based on the geometric thickness of the layer.

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

The silicon oxide may be doped with, for example, aluminum, zirconium, titanium, boron, or hafnium. In particular, the optical, mechanical and chemical properties of the coating can be adjusted by means of dopants.

The optical low refractive layer is preferably applied to the inner side surface of the optical high refractive thin glass plate by magnetron enhanced cathode sputtering ("magnetron sputtering") or by wet coating onto the inner side surface of the optical high refractive thin glass plate. The optically low refractive layer may also be applied to the inner side surface of the optically high refractive thin glass plate, for example by sol-gel method.

In a preferred embodiment, the optically low refractive layer is based on nanoporous silica. The reflective properties of such layers 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 is in turn a function of the pore size and pore density. The nanoporous silica may be doped with, for example, aluminum, zirconium, titanium, boron, tin, or zinc. In particular, the optical, mechanical and chemical properties of the coating can be adjusted by means of dopants. The optical low refractive layer formed based on nanoporous silica preferably comprises only one homogeneous layer of nanoporous silica. However, the low refractive layer may be formed of, for example, a plurality of nanoporous silica layers different from each other in terms of porosity (size and/or density of pores). Thus, it appears that a gradual change in refractive index may be generated. The pores are in particular closed nanopores, but may also be open pores. The term "nanopore" refers to a pore having a size in the nanometer range, i.e. 1nm to less than 1000nm (1 μm). The aperture preferably has a substantially circular cross-section (spherical aperture), but may also have other cross-sections, such as elliptical, oval or elongated cross-sections (elliptical or oval aperture). Preferably, at least 80% of all apertures have substantially the same cross-sectional shape. Pore sizes of at least 20nm or even at least 40nm may be advantageous. The average size of the pores is preferably from 1nm to 500nm, particularly preferably from 1nm to 100nm, most particularly preferably from 20nm to 80nm, the term "pore size" referring to the diameter in the case of circular pores; in the case of another shaped aperture, the maximum length. Preferably, at least 80% of all pores have a size within the indicated range; it is particularly preferred that all of the pores have dimensions within the ranges shown. The proportion of pore volume in the total volume is preferably from 10% to 90%, particularly preferably less than 80%, most particularly preferably less than 60%.

The optically low refractive layer based on nanoporous silica is preferably a sol-gel coating. Which is deposited on the inside surface of an optically high refractive thin glass plate in a sol-gel process. First, a sol containing a coating precursor is provided and cured. Curing may include hydrolysis of the precursors and/or (partial) reactions between the precursors. In the context of the present invention, the sol is referred to as a precursor sol and contains a silica precursor in a solvent. The precursor is preferably a silane, in particular tetraethoxysilane or Methyltriethoxysilane (MTEOS). However, silicate esters may alternatively be used as precursors, in particular sodium silicate, lithium silicate or potassium silicate, for example tetramethyl orthosilicate, orthosilicateTetraethyl acid (TEOS), tetraisopropyl orthosilicate or a compound of the general formula R ² _n Si(OR ¹ ) _4-n Is an organosilane of (2). Here, R is preferably ¹ Is an alkyl group; r is R ² Is alkyl, epoxy, acrylate, methacrylate, amine, phenyl or vinyl; and n is an integer from 0 to 2. Silicon halides or alkoxides may also be used. The solvent is preferably water, an alcohol (in particular ethanol) or a water-alcohol mixture. The precursor sol is then mixed with a pore-forming agent dispersed in an aqueous phase. The purpose of the pore former is to create pores in the silica matrix, so to speak, as placeholders for creating 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 size, pore distribution, and pore density can be selectively controlled by the pore former and ensure reproducible results. The polymer nanoparticles can be used, for example, as pore formers, preferably PMMA nanoparticles (polymethyl methacrylate), but also nanoparticles of polycarbonate, polyester or polystyrene, or copolymers of (meth) acrylic acid and (meth) acrylic acid. Instead of polymer nanoparticles, it is also possible to use nanodroplets of oil in the form of nanoemulsions. Of course, the use of different pore formers is also contemplated. The solution thus obtained was applied to the inner side surface of an optically high refractive thin glass plate. This is reasonably done by wet chemistry. The sol is then concentrated. In this process, a silica matrix is formed around the pore former. Condensation may include temperature treatment, for example at temperatures up to 350 ℃. If the precursor has UV crosslinkable functional groups (e.g., methacrylate, vinyl, or acrylate groups), the condensation may include UV treatment. Alternatively, for suitable precursors (e.g., silicate esters), the condensation may include IR treatment. Optionally, the solvent may be evaporated at a temperature up to 120 ℃. The pore-forming agent is then optionally removed. For this purpose, the coated substrate is preferably subjected to a heat treatment at a temperature of at least 400 ℃, preferably at least 500 ℃, wherein the pore-forming agent decomposes. The organic pore formers are particularly "carbonized". The heat treatment may be performed as part of a bending process or a thermal tempering process. The heat treatment is preferably carried out for a period of up to 15 minutes, particularly preferably up to 5 minutes. In addition to removing pore-forming agent, heat treatment The process can also be used to complete the condensation and thus densify the coating, which improves its mechanical properties, in particular its stability. Instead of using a heat treatment, the pore-forming agent may also be dissolved from the coating by a solvent. In the case of polymer nanoparticles, the corresponding polymers must be soluble in solvents, for example, in the case of PMMA nanoparticles Tetrahydrofuran (THF) can be used. The spacing agent is preferably removed to create void spaces. In principle, however, it is also possible to leave the pore-forming agent in the pores. This is thereby affected if it has a refractive index different from that of silicon oxide. The pores are then filled with a pore former, for example PMMA nanoparticles. Hollow particles can also be used as pore formers, for example hollow polymer nanoparticles, such as PMMA nanoparticles or hollow silica nanoparticles. If such a pore former is left in the pores without removal, the pores have a hollow core and edge regions filled with the pore former.

The sol-gel process is capable of producing a regular, uniformly distributed optical low refractive layer with voids. The pore shape, size and density can be selectively adjusted, and the optical low refractive layer has a low tortuosity.

Due to the fact that the reflective element is arranged in a region of the composite glass pane which is located entirely in the region in which the masking layer is arranged when viewed perpendicularly through the composite glass pane, the reflective element is thereby free of parts which do not overlap with the masking layer, i.e. the reflective element is formed only in front of the masking layer when viewed from the inside through the composite glass pane. The reflective element is thus arranged spatially in front of the masking layer from the perspective of the vehicle occupant.

As described above, in the composite glass sheet according to the present invention, the masking layer is disposed in one region of the composite glass sheet. Preferably, the masking layer is disposed in an edge region of the composite glass sheet, which edge region is generally adjacent to a side edge of the glass sheet. The main advantage of this arrangement comes from the use of a composite glass pane as a windscreen in the vehicle, since the masking layer is located outside the main perspective area of the driver when arranged in the edge area.

Preferably, the masking layer is disposed at least along and adjacent to the lower edge. This produces a rectangular opaque strip disposed along the lower edge when the composite glass sheet is viewed from above.

In a particularly preferred embodiment of the composite glass sheet according to the invention, the masking layer is implemented circumferentially in a frame-like manner. In the portion in which the reflective element is arranged overlapping the masking layer, the frame-like masking layer is preferably provided with a widening, i.e. has a greater width (a dimension extending perpendicular thereto) than in the other portions. The masking layer can thus be adapted appropriately to the dimensions of the reflective element.

Thus, in one embodiment, the masking layer is implemented circumferentially in a frame-like manner and has a greater width, in particular in one portion overlapping the reflective element, than in a different portion thereof.

A masking layer formed circumferentially in a frame-like manner is preferably used for masking the gluing of a composite glass pane (for example as a windscreen in a vehicle body). The overall impression of harmony of the composite glass pane in the installed state is thereby achieved. Furthermore, such masking layers serve as UV protection for the adhesive material used.

An advantage of the present invention is that the reflective element is disposed on the inside surface of the inner glass sheet. Thereby, the surface on which the masking layer is to be placed can be freely selected according to the wishes of the consumer. In contrast, the reflective element provided on the outer side surface of the inner glass plate or the inner side surface of the outer glass plate may be masked by a masking print (masking print) located further inside in the direction inside the vehicle. This is avoided by means of the structure according to the invention. When the masking layer is arranged on the inner side surface of the inner glass pane, the adhesive layer is arranged on the surface of the masking layer facing away from the inner glass pane, and thus the reflective element is not adversely affected in its function by the masking layer.

The reflective element and thus the optical high-refractive thin glass sheet provided with an optical low-refractive layer on the inner side surface preferably have a substantially rectangular shape extending between the two side edges of the composite glass sheet in an area near the lower edge. Particularly preferably, the edges of the optically high refractive thin glass sheet of the reflective element do not touch the side edges and the lower edges of the composite glass sheet, but are spaced apart therefrom by a distance of, for example, 2cm to 5 cm.

As described above, the reflective element is arranged in the region of the composite glass sheet. The reflective element does not extend over the entire composite glass sheet. Thus, the reflective element is smaller in its outer dimensions (i.e., width and length) than the outer and inner glass sheets of the composite glass sheet. The reflective element preferably extends over a maximum of 50%, particularly preferably over a maximum of 30%, most particularly preferably over a maximum of 20% of the composite glass pane.

In the context of the present invention, a masking layer is a layer that prevents perspective through the composite glass sheet. The transmission of light of the visible spectrum through the masking layer takes place at most 5%, preferably at most 2%, particularly preferably at most 1%, in particular at most 0.1%. The masking layer is thus an opaque masking layer, preferably a black masking layer.

The masking layer is preferably a coating of one or more layers. Alternatively, the masking layer may be a colored region of the thermoplastic interlayer. According to a preferred embodiment of the composite glass sheet, the masking layer consists of a single layer. This has the advantage that the composite glass sheet is produced particularly simply and economically, since only one single layer needs to be formed for the masking layer.

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

In a preferred embodiment, the masking layer is implemented as an opaque masking print, in particular a dark (preferably black) enamel, arranged on the inner side surface of the outer glass pane.

In an alternative preferred embodiment, the masking layer is implemented as an opaque masking print, in particular a dark (preferably black) enamel, arranged on the outer side surface of the inner glass pane.

In an alternative preferred embodiment, the masking layer is implemented as an opaque masking print, in particular a dark (preferably black) enamel, arranged on the inner side surface of the inner glass pane.

In an alternative preferred embodiment, the masking layer is implemented as an opaque colored region of the thermoplastic intermediate layer. In one embodiment, the thermoplastic interlayer is formed as a single piece and is opaque colored in one region. By using a thermoplastic intermediate layer composed of an opaque thermoplastic film and a transparent thermoplastic film, a masking layer implemented as an opaque colored region of the thermoplastic intermediate layer can also be realized. The opaque thermoplastic film and the transparent thermoplastic film are preferably arranged offset from one another such that the two films do not overlap when viewed through the composite glass sheet. The transparent and opaque thermoplastic films are made of or preferably contain the same plastic. Materials based on which opaque thermoplastic films and transparent thermoplastic films can be formed are also those described for thermoplastic interlayers. The opaque thermoplastic film is preferably a colored film which may have various colors, particularly black.

Preferably, the adhesive layer is a thermoplastic layer or a so-called Optically Clear Adhesive (OCA). Suitable Optically Clear Adhesives (OCAs) are known to those skilled in the art. The adhesive layer embodied 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 of a thermoplastic film (adhesive film). The thickness of the thermoplastic layer is preferably from 0.2mm to 2mm, particularly preferably from 0.3mm to 1mm, for example 760 μm. The thermoplastic layer may be formed from a single film or from more than one film.

The composite glass sheet is preferably bent in one or more spatial directions, as is commonly used for automotive glass sheets, with typical radii of curvature ranging from about 10cm to about 40m. However, the composite glass sheet may also be planar, for example when it is intended to be used as a glass sheet for a bus, train or tractor.

The thermoplastic interlayer thereby joining the outer glass sheet and the inner glass sheet comprises 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 formed from a thermoplastic film (adhesive film). The thickness of the thermoplastic intermediate layer is preferably from 0.2mm to 2mm, particularly preferably from 0.3mm to 1mm, for example 760 μm. The thermoplastic interlayer may be formed from a single film or from more than one film. The thermoplastic intermediate layer may also be a film having functional properties, such as a film having acoustic damping properties.

The outer and inner glass panes preferably comprise or consist of glass, particularly preferably flat glass, float glass, quartz glass, borosilicate glass, soda lime glass, aluminosilicate glass, or comprise or consist of transparent plastic, preferably rigid transparent plastic, in particular polyethylene, polypropylene, polycarbonate, polymethyl methacrylate, polystyrene, polyamide, polyester, polyvinyl chloride and/or mixtures thereof.

The outer and inner glass sheets may be transparent and colorless, but may also be tinted or colored. The outer and inner glass sheets may be non-prestressed, partially prestressed or prestressed independently of each other. If at least one of the glass sheets is to be pre-stressed, this may be thermally or chemically pre-stressed.

The composite glass pane according to the invention is preferably embodied as a windscreen. In a preferred embodiment, the total transmission through the windshield in the main see-through region is greater than 70% (light source a). The term "total transmittance" is based on the method specified in ECE-R43, appendix 3, ≡9.1 for testing the light transmission of a motorized vehicle window.

The outer and inner glass sheets may have suitable coatings known per se, such as anti-reflective, non-stick, scratch-resistant, photocatalytic or sun-shading coatings or low-emissivity coatings.

The thickness of the outer and inner glass sheets can vary widely and can thus be adapted to the needs of the individual situation. The outer and inner glass sheets preferably have a thickness of 0.5mm to 5mm, particularly preferably 1mm to 3mm, most particularly preferably 1.6mm to 2.1 mm. For example, the outer glass sheet has a thickness of 2.1 mm; and the inner glass sheet has a thickness of 1.6 mm. However, the outer glass pane or in particular the inner glass pane may also be a thin glass with a thickness of, for example, 0.55 mm.

The optically high refractive thin glass plate is preferably a so-called flint glass. Typically, optically high refractive glasses contain dopants with elements such as lead, barium or lanthanum. The optically high-refractive thin glass sheet may be composed of glass having a high refractive index as disclosed in, for example, DE 11 2011 104 339 B4, DE10 2020 120 A1 or WO 2019/131123 A1.

The composite glass sheet according to the invention may comprise one or more additional interlayers, in particular functional interlayers. The additional intermediate layer may in particular be an intermediate layer having acoustic damping properties, an intermediate layer reflecting infrared radiation, an intermediate layer absorbing UV radiation, an intermediate layer colored at least in certain parts and/or an intermediate layer colored at least in certain parts. If there are a plurality of additional intermediate layers, these may even have different functions. The additional intermediate layer is preferably arranged between the inner glass pane and the outer glass pane.

In one embodiment, the composite glass sheet includes a HUD reflective layer, also referred to hereinafter as a HUD layer, disposed between the inside surface of the outer glass sheet and the outside surface of the inner glass sheet.

The principles of head-up displays (HUDs) and technical terms from the field of HUDs as used herein are generally known to those skilled in the art. For a detailed description, refer to The paper "formulation-Based Measurement Technology for Testing Head-Up Display" (Munich: university Library of The Technical University of Munich, 2012) at Alexander Neumann at Institute of Computer Science of Technical University of Munich, in particular chapter 2 "The Head-Up Display". The HUD layer is disposed between the outer and inner glass sheets, where "between" may refer to within the thermoplastic interlayer or may refer to direct spatial contact on the inside surface of the outer glass sheet and on the outside surface of the inner glass sheet. The HUD layer is suitably designed to reflect p-polarized light. The HUD layer is a reflective coating that is incorporated into the composite glass sheet over a large area, and the area in which the HUD coating is located is also referred to as the HUD area. To use the composite glass sheet as a heads-up display, the projector is aimed at the HUD area of the composite glass sheet. The radiation of the projector is preferably mainly p-polarized. The HUD layer is adapted to reflect p-polarized radiation. Thus, radiation from the projector creates a virtual image that the vehicle driver can perceive from its perspective as being behind the composite glass sheet.

Since the reflective element is bonded to the inner side surface of the inner glass plate via the adhesive layer, the HUD layer may be arranged between the outer glass plate and the inner glass plate of the composite glass plate independently of the reflective element and 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 comprising a stack of thin layers, i.e. a sequence of thin individual layers. The thin layer stack contains one or more silver-based conductive layers. The silver-based conductive layer imparts basic reflective properties, IR reflecting effects and conductivity to the reflective coating. The conductive layer is based on silver. The conductive layer preferably contains at least 90 wt.% silver, particularly preferably at least 99 wt.% silver, most particularly preferably at least 99.9 wt.% silver. The silver layer may have a dopant such as palladium, gold, copper or aluminum. Silver-based materials are particularly suitable for reflecting p-polarized light. The use of silver has proven to be particularly advantageous in reflecting p-polarized light. The coating has a thickness of 5nm to 50nm and preferably 8nm to 25 nm. If the HUD layer is applied as a coating, it is preferably applied to the inner or outer glass pane by Physical Vapor Deposition (PVD), particularly preferably by cathode sputtering ("sputtering"), and most particularly preferably by magnetron enhanced cathode sputtering ("magnetron sputtering"). In principle, however, the coating can also be applied, for example, using Chemical Vapor Deposition (CVD), such as plasma-enhanced vapor deposition (PECVD), by vapor deposition, or by Atomic Layer Deposition (ALD). The coating is applied to the glass sheet prior to lamination.

The HUD layer may also be implemented as a reflective film that reflects p-polarized light. The HUD layer may be a carrier film or a reflective polymer film with a reflective coating. The reflective coating preferably comprises at least one metal-based layer and/or a sequence of dielectric layers having alternating refractive indices. The metal-based layer preferably contains or consists of silver and/or aluminum. The dielectric layer may be based, for example, on silicon nitride, zinc oxide, tin zinc oxide, mixed silicon-metal nitrides such as zirconium silicon nitride, zirconium oxide, niobium oxide, hafnium oxide, tantalum oxide, or silicon carbide. The oxides and nitrides mentioned may be deposited stoichiometrically, sub-stoichiometrically or super-stoichiometrically. They may have dopants, for example aluminium, zirconium, titanium or boron. The reflective polymer film preferably comprises or consists of a dielectric polymer layer. The dielectric polymer layer preferably comprises PET. If the HUD layer is implemented as a reflective film, it is preferably 30 μm to 300 μm thick, particularly preferably 50 μm to 200 μm thick, and in particular 100 μm to 150 μm thick. If it is a coated reflective film, it can also be produced using a CVD or PVD coating method. According to another preferred embodiment, the HUD layer is implemented as a reflective film and is arranged within the thermoplastic intermediate layer. An advantage of this arrangement is that it is not necessary to apply the HUD layer on the outer or inner glass pane by means of thin film techniques, such as CVD and PVD. This results in the use of HUD layers with other advantageous functions, such as more uniform reflection of p-polarized light on the HUD layer. Furthermore, the production of the composite glass sheet can be simplified, since the HUD layer does not have to be arranged on the outer glass sheet or the inner glass sheet via an additional process prior to lamination.

The invention also relates to a projection assembly comprising at least a composite glass sheet glass according to the invention and an imaging unit of an alignment reflective element, which unit emits p-polarized light, wherein the inner side surface of the inner glass sheet glass is the surface of the inner glass sheet closest to the imaging unit.

The invention thus also includes a projection assembly comprising at least:

a composite glass sheet comprising at least an outer glass sheet having an outer side surface and an inner side surface, a thermoplastic interlayer, an inner glass sheet having an outer side surface and an inner side surface, a masking layer, an adhesive layer, and a reflective element comprising an optically high refractive thin glass sheet having an outer side surface, an inner side surface, a thickness of 20 μm to 500 μm, and a refractive index of 1.9 or more, and an optically low refractive layer having a refractive index of 1.6 or less coated on the inner side surface of the optically high refractive thin glass sheet,

wherein a thermoplastic interlayer is disposed between the outer glass sheet and the inner glass sheet,

an adhesive layer is disposed between the inner glass sheet and the reflective element,

the shielding layer is arranged between the outer glass sheet and the inner glass sheet or on the inner side surface of the inner glass sheet in one region of the composite glass sheet,

The outer side surface of the optically high refractive thin glass plate is bonded to the inner side surface of the inner glass plate via an adhesive layer,

and wherein the reflective element is arranged in a region of the composite glass sheet, said region being located entirely in the region in which the masking layer is arranged when viewed perpendicularly through the composite glass sheet,

and an imaging unit which is aligned with the reflective element and emits p-polarized light,

wherein the inner side surface of the inner glass sheet is the surface of the inner glass sheet closest to the imaging unit.

In particular, the combination of the reflective element with the masking layer behind it achieves good image visibility in the projection assembly according to the invention from the perspective of the vehicle occupant, even in the case of external gaze and using a low-light imaging unit. Even in these cases, the image produced by the imaging unit appears bright and can be well recognized. This enables to reduce the power of the imaging unit and thereby the power consumption.

From the perspective of the vehicle occupant, the reflective element is spatially arranged in front of the masking layer when viewed through the inner glass pane. Thus, the region of the composite glass sheet in which the reflective element is disposed appears opaque. The expression "when viewed through the composite glass sheet" means that the viewing through the composite glass sheet is from the inside, i.e. the inner side surface of the inner layer glass sheet is the surface of the inner layer glass sheet closest to the viewer. In the context of the present invention, "spatially forward" means that the reflective element is spatially disposed farther from the outer surface of the outer glass sheet than the masking layer. Preferably, the masking layer is widened at least in the region overlapping the reflective element. This means that in this region, which is viewed perpendicularly to the nearest part of the peripheral edge of the composite glass sheet, the masking layer has a greater width than in the other parts. In this way, the masking layer can be adapted to the size of the reflective element.

The imaging unit is used for emitting an image, i.e. it may also be referred to as projector, display device or image display device. For example, a display or even another device known to a person skilled in the art may be used as the imaging unit. Preferably, the imaging unit is a display, particularly preferably an LCD display, an LED display, an OLED display or an electroluminescent display, in particular an LCD display. The display has a low installation height and can thus be integrated easily and space-effectively into the dashboard of the vehicle. Furthermore, the operation of the display is significantly more energy efficient than the imaging unit. In the combination according to the invention of the reflective element with the masking layer located behind it, a relatively low brightness of the display is entirely sufficient. The imaging unit emits p-polarized light. The radiation of the imaging unit preferably impinges on the composite glass pane in the region of the reflective element at an angle of incidence of 55 ° to 80 °, preferably 62 ° to 77 °. The angle of incidence is the angle between the incident vector of the radiation from the imaging unit and the surface normal in the geometric center of the reflective element.

The p-polarized light emitted by the imaging unit irradiates the reflecting element and is reflected there. The light reflected by the reflective element is preferably visible light, i.e. light in the wavelength range of about 380nm to 780 nm. The reflective element preferably has a high and uniform reflectivity (at various angles of incidence) for p-polarized radiation so that a high intensity and color neutral image display is ensured.

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

The term "p-polarized light" refers to light of the visible spectrum consisting essentially of light having p-polarization. The p-polarized light preferably has a light proportion 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 about 100%.

The indication of the polarization direction is based on the plane of incidence of the radiation on the composite glass sheet. "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 generated by the incident vector and the surface normal of the composite glass sheet at the geometric center of the illuminated area. In other words, the polarization, i.e. in particular the ratio of p-polarized radiation and s-polarized radiation, is determined at one point of the area illuminated by the light source, preferably at the geometric center of the illuminated area. Since the composite glass sheets can be curved (for example when they are windshields), thereby influencing the plane of incidence of the radiation of the imaging unit, slightly deviating polarization ratios can occur in the remaining areas, which is unavoidable for physical reasons.

The inventors have found that a reflective element comprising an optically high refractive thin glass plate having a thickness of 20 μm to 500 μm and a refractive index of 1.9 or more and a low refractive layer having a refractive index of 1.6 or less has a particularly uniform reflection behavior and thus a better color neutrality and is furthermore more sensitive to fingerprints than a reflective layer comprising an optically high refractive layer and an optically low refractive layer. Furthermore, the combination of the reflective element according to the invention with the masking layer behind it from the perspective of the vehicle occupant achieves good image visibility even in the case of external gaze, the occupant wearing sunglasses, and the use of low-light imaging units. Even in these cases, the image produced by the imaging unit appears bright and can be well recognized. This enables the power of the imaging unit to be reduced and thereby the power consumption to be reduced.

The projection assembly according to the invention is particularly suitable for being combined with a HUD layer. In this case, as described above, in one embodiment of the composite glass sheet according to the present invention, the composite glass sheet has the HUD layer disposed between the outer layer glass sheet and the inner layer glass sheet. In this embodiment, the reflective element and the masking layer provided in this region are limited only locally to the edge region of the composite glass pane and therefore do not affect the HUD layer applied in the see-through region of the composite glass pane.

The composite glass sheet of the projection assembly is preferably a windshield. The optional HUD layer is located at least in the main see-through region of the windshield.

The preferred embodiments of the composite glass sheet according to the invention described above are also applicable, mutatis mutandis, to projection assemblies according to the invention comprising a composite glass sheet according to the invention and an imaging unit, and vice versa.

The invention also includes a method for producing a composite glass sheet according to the invention, comprising at least:

a) Providing a composite of an outer glass sheet having an outer side surface and an inner side surface, a thermoplastic interlayer, and an inner glass sheet having an outer side surface and an inner side surface, wherein the thermoplastic interlayer is disposed between the outer glass sheet and the inner glass sheet, and the masking layer is disposed in one region between the outer glass sheet and the inner glass sheet or on the inner side surface of the inner glass sheet;

b) Providing a reflective element comprising an optically high refractive thin glass plate having an outer side surface, an inner side surface, a thickness of 20 μm to 500 μm and a refractive index of 1.9 or more, and an optically low refractive layer having a refractive index of 1.6 or less applied on the inner side surface of the optically high refractive thin glass plate;

c) The outer side surface of the optically high refractive thin glass sheet is bonded to the inner side surface of the inner layer glass sheet of the composite material via the adhesive layer to form the composite glass sheet such that the reflective element is disposed in a region of the composite glass sheet that is entirely in the region in which the masking layer is disposed when viewed perpendicularly through the composite glass sheet.

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

As described above, the reflective element is disposed in a region of the composite glass sheet that is entirely within the region in which the masking layer is disposed when viewed perpendicularly through the composite glass sheet. The reflective element is thus smaller in its outer dimensions than the outer and inner glass sheets of the composite glass sheet. In step b), the reflective element may be provided by applying an optical low refractive layer having a refractive index of less than or equal to 1.6 on the entire inner side surface of the optical high refractive thin glass plate having a thickness of 20 μm to 500 μm, a refractive index of greater than or equal to 1.9, and having a desired size.

Alternatively, in step b), it is also possible to apply an optically low refractive layer having a refractive index of less than or equal to 1.6 on the entire inner side surface of an optically high refractive sheet glass having a thickness of 20 μm to 500 μm and a refractive index of greater than or equal to 1.9, the outer dimensions (i.e. width and length) thereof being greater than desired, and subsequently cut out sheets having the desired dimensions from such coated sheet glass, for example by means of a laser cutting process, thereby providing the reflective element.

If the composite glass sheet is to be bent, a bent outer glass sheet and a bent inner glass sheet are used in providing the composite material in step a). Due to the low thickness of the optically high refractive thin glass plate, the reflective element is flexible and accommodates the curved inner glass plate of the composite material in step c). This is an advantage of the method according to the invention.

In step a), the composite material may be provided by lamination methods familiar to those skilled in the art.

In providing the reflective element in step b), the application of the optical low refractive layer may be performed by commonly known coating methods, such as magnetron sputtering or wet coating.

The preferred embodiments of the composite glass sheet according to the invention described above are also applicable, mutatis mutandis, to a method for producing a composite glass sheet according to the invention.

The invention also relates to the use of the composite glass pane according to the invention as a vehicle glass pane in a movement pattern for traveling on land, in air or on water, in particular in a motor vehicle, and in particular as a windscreen for a head-up display.

The invention will be explained in more detail below with reference to the drawings and to exemplary embodiments. The figures are schematic representations and are not drawn to scale. The drawings are in no way limiting of the invention.

They depict:

figure 1 is a plan view of one embodiment of a composite glass sheet according to the present invention,

figure 2 is a cross-sectional view through the embodiment depicted in figure 1,

figure 3 is a cross-sectional view through another embodiment of a composite glass sheet according to the invention,

figure 4 is a cross-sectional view through another embodiment of a composite glass sheet according to the invention,

figure 5 is a cross-sectional view through another embodiment of a composite glass sheet according to the invention,

figure 6 is a plan view of another embodiment of a composite glass sheet according to the invention,

figure 7 is a cross-sectional view through the embodiment depicted in figure 6,

figure 8 is a cross-sectional view through another embodiment of a composite glass sheet according to the invention,

FIG. 9 is a cross-sectional view through another embodiment of a composite glass sheet according to the invention

Figure 10 is a cross-sectional view through another embodiment of a composite glass sheet according to the invention,

figure 11 is a cross-sectional view through another embodiment of a composite glass sheet according to the invention,

figure 12 is a cross-sectional view through one embodiment of a projection assembly according to the present invention,

figure 13 is a cross-sectional view through another embodiment of a projection assembly according to the present invention,

figure 14 uses an exemplary embodiment of a method according to the present invention of a flow chart,

figure 15 is a reflection spectrum of p-polarized radiation at an angle of incidence of 60,

figure 16 is a reflection spectrum of p-polarized radiation at an angle of incidence of 65,

figure 17 is a reflection spectrum of p-polarized radiation at an angle of incidence of 70,

fig. 18 is a reflection spectrum of p-polarized radiation at an angle of incidence of 75 deg. for a composite glass sheet.

Fig. 1 depicts a plan view of one embodiment of a composite glass sheet 100 according to the present invention, and fig. 2 depicts a cross-section through the composite glass sheet 100 depicted in fig. 1 along section line X-X'. The composite glass sheet 100 depicted in fig. 1 and 2 has an upper edge O, a lower edge U and two side edges S, and comprises an outer glass sheet 1 having an outer side surface I and an inner side surface II, an inner glass sheet 2 having an outer side surface III and an inner side surface IV, a thermoplastic interlayer 3, a masking layer 4, an adhesive layer 5 and a reflective element 6, the reflective element 6 comprising an optically high refractive thin glass sheet 7 having an outer side surface V and an inner side surface VI and an optically low refractive layer 8. A thermoplastic interlayer 3 is arranged between the outer glass pane 1 and the inner glass pane 2; the inner glass pane 2 is arranged between the outer glass pane 1 and the reflective element 6; and an adhesive layer 5 is arranged between the inner glass plate 2 and the reflective element 6. The outer glass sheet 1, the thermoplastic interlayer 3 and the inner glass sheet 2 are arranged in this order over the entire surface. The masking layer 4 is arranged between the outer layer glass pane 1 and the inner layer glass pane 2 in one region of the composite glass pane 100. In the embodiment depicted in fig. 1 and 2, the masking layer 4 is implemented as an opaque masking print arranged on the inner side surface II of the outer layer glass pane 1 and is arranged only in the edge region of the composite glass pane 100 adjacent to the lower edge U. The reflective element 6 is arranged in a region of the composite glass sheet 100 which, when viewed perpendicularly through the composite glass sheet 100, is entirely located in the region in which the masking layer 4 is arranged. The reflective element 6 is thus smaller in its outer dimension than the inner glass pane 2. The outer side surface V of the optically high refractive thin glass plate 7 is bonded to the inner side surface IV of the inner glass plate 2 via the adhesive layer 5. An optical low refractive layer 8 is provided on the inner side surface VI of the optical high refractive thin glass plate 7.

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

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

Needless to say, composite glass sheet 100 can have any suitable geometry and/or curvature. Typically, the composite glass sheet 100 is a bent composite glass sheet.

Fig. 3 depicts a cross-section through another embodiment of a composite glass sheet 100 according to the present invention. The embodiment depicted in cross section in fig. 3 differs from the embodiment depicted in fig. 2 only in that the masking layer 4 is not implemented as an opaque masking print arranged on the inner side surface II of the outer glass pane 1, but as an opaque masking print arranged on the outer side surface III of the inner glass pane 2.

Fig. 4 depicts a cross-section through another embodiment of a composite glass sheet 100 according to the present invention. The embodiment depicted in cross section in fig. 4 differs from the embodiment depicted in fig. 2 only in that the masking layer 4 is not implemented as an opaque masking print arranged on the inner side surface II of the outer glass pane 1, but as an opaque colored region of the thermoplastic intermediate layer 3.

Fig. 5 depicts a cross-section through another embodiment of a composite glass sheet 100 according to the present invention. The embodiment depicted in cross section in fig. 5 differs from the embodiment depicted in fig. 2 only in that the masking layer 4 is not implemented as an opaque masking print arranged on the inner side surface II of the outer glass pane 1, but as an opaque masking print arranged on the inner side surface IV of the inner glass pane 2. Needless to say, in this embodiment, the adhesive layer 5 is not disposed directly adjacent to the inner side surface IV of the inner layer glass plate 2, but is disposed directly adjacent to the masking layer 4 disposed on the inner side surface IV of the inner layer glass plate 2.

Fig. 6 depicts a plan view of another embodiment of a composite glass sheet 100 according to the present invention, and fig. 7 depicts a cross-section through the composite glass sheet 100 depicted in fig. 6 along section line Y-Y'. The composite glass sheet 100 depicted in fig. 6 and 7 has an upper edge O, a lower edge U and two side edges S, and comprises an outer glass sheet 1 having an outer side surface I and an inner side surface II, an inner glass sheet 2 having an outer side surface III and an inner side surface IV, a thermoplastic interlayer 3, a masking layer 4, an adhesive layer 5 and a reflective element 6, the reflective element 6 comprising an optically high refractive thin glass sheet 7 having an outer side surface V and an inner side surface VI and an optically low refractive layer 8. A thermoplastic interlayer 3 is arranged between the outer glass pane 1 and the inner glass pane 2; the inner glass pane 2 is arranged between the outer glass pane 1 and the reflective element 6; and an adhesive layer 5 is arranged between the inner glass plate 2 and the reflective element 6. The outer glass sheet 1, the thermoplastic interlayer 3 and the inner glass sheet 2 are arranged in this order over the entire surface. The masking layer 4 is arranged between the outer layer glass pane 1 and the inner layer glass pane 2 in one region of the composite glass pane 100. The region in which the masking layer 4 is arranged is provided with reference a. In the embodiment depicted in fig. 6 and 7, the masking layer 4 is implemented as an opaque masking print arranged on the inner side surface II of the outer glass pane 1 and in a circumferential edge region having a greater width in the portion overlapping the reflective element 6 than in a different portion thereof. For simplicity of illustration, the masking layer depicted in fig. 6 is not shown in black, but is patterned. The reflective element 6 is arranged in a region of the composite glass sheet 100 which, when viewed perpendicularly through the composite glass sheet 100, is located entirely in the region in which the shielding layer 4 is arranged, and is provided with the reference sign B in fig. 6. The reflective element 6 is thus smaller in its outer dimension than the inner glass pane 2. The outer side surface V of the optically high refractive thin glass plate 7 is bonded to the inner side surface IV of the inner glass plate 2 via the adhesive layer 5. An optical low refractive layer 8 is arranged on the inner side surface VI of the optical high refractive thin glass plate 7.

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

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

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

Fig. 8 depicts a cross-section through another embodiment of a composite glass sheet 100 according to the present invention. The embodiment depicted in cross section in fig. 8 differs from the embodiment depicted in fig. 7 only in that the masking layer 4 is not implemented as an opaque masking print arranged on the inner side surface II of the outer glass pane 1, but as an opaque masking print arranged on the outer side surface III of the inner glass pane 2.

Fig. 9 depicts a cross-section through another embodiment of a composite glass sheet 100 according to the present invention. The embodiment depicted in cross section in fig. 9 differs from the embodiment depicted in fig. 7 only in that the masking layer 4 is not implemented as an opaque masking print arranged on the inner side surface II of the outer glass pane 1, but as an opaque colored region of the thermoplastic intermediate layer 3.

Fig. 10 depicts a cross-section through another embodiment of a composite glass sheet 100 according to the present invention. The embodiment depicted in cross section in fig. 10 differs from the embodiment depicted in fig. 7 only in that the masking layer 4 is not implemented as an opaque masking print arranged on the inner side surface IJ of the outer layer glass pane 1, but as an opaque masking print arranged on the inner side surface IV of the inner layer glass pane 2. Needless to say, in this embodiment, the adhesive layer 5 is not disposed directly adjacent to the inner side surface IV of the inner layer glass plate 2, but is disposed directly adjacent to the masking layer 4 disposed on the inner side surface IV of the inner layer glass plate 2.

Fig. 11 depicts a cross-section through another embodiment of a composite glass sheet 100 according to the present invention. The embodiment depicted in cross section in fig. 11 differs from the embodiment depicted in fig. 2 only in that the composite glass sheet 100 additionally has a HUD reflective layer 9 arranged between the inner glass sheet 2 and the thermoplastic intermediate layer 3. The HUD reflective layer 9 also extends into the see-through region of the composite glass sheet 100, i.e., the region where the masking layer 4 is not present. The HUD reflective layer 9 is implemented as a p-polarized light reflective layer.

Fig. 12 depicts a cross-section through one embodiment of a projection assembly 101 according to the present invention. The projection assembly 101 depicted in fig. 12 includes a composite glass sheet 100 and an imaging unit 10. In the embodiment of the projection assembly according to the invention depicted in fig. 12, a composite glass plate 100 is implemented as shown in fig. 2, wherein the optically high refractive thin glass plate 7 of the reflective element 6 and the optically low refractive layer 8 are not shown separately. Needless to say, the composite carrier glass sheet may alternatively be implemented as in fig. 3, 4, 5, 7, 8, 9, 10 or 11. The projection assembly 101 has an imaging unit 10. The imaging unit 10 is used to generate p-polarized light (image information) which is directed to the reflective element 6 and reflected by the reflective element 6 into the interior of the vehicle as reflected light, where it can be perceived by an observer, for example a driver. The light preferably impinges the reflective element at an angle of incidence of 55 ° to 80 °, in particular 62 ° to 77 °. The imaging unit 10 is, for example, a display, in particular an LCD display.

Fig. 13 depicts a cross-section through another embodiment of a projection assembly 101 according to the present invention. The embodiment depicted in fig. 13 differs from the embodiment depicted in fig. 12 only in that the composite glass sheet 100 additionally has a HUD reflective layer 9 arranged between the inner glass sheet 2 and the thermoplastic interlayer 3. The HUD reflecting layer 9 is implemented as a p-polarized light reflecting layer. The HUD reflective layer 9 also extends into the see-through region of the composite glass sheet 100, i.e. the region where the masking layer 4 is not present. A projector (not shown) emitting p-polarized light may be directed to the region of the glass plate and the HUD reflecting layer 9 may serve as a projection surface for the virtual image. The image projected by the imaging unit 10 onto the reflective element 6 is easily recognizable with high contrast in front of the background of the masking layer 4 (markierungschicht 4). The HUD reflecting layer 9 may be used independently of the reflecting element 6, whereby the image reflected by the reflecting element 6 and the HUD image do not affect each other.

Fig. 14 depicts an exemplary embodiment of a method according to the present invention using a flow chart.

In a first step S1, a composite material of an outer glass pane 1 having an outer side surface I and an inner side surface II, a thermoplastic interlayer 3, and an inner glass pane 2 having an outer side surface III and an inner side surface IV is provided, wherein the thermoplastic interlayer 3 is arranged between the outer glass pane 1 and the inner glass pane 2, and the masking layer 4 is arranged in one region between the outer glass pane 1 and the inner glass pane 2 or on the inner side surface IV of the inner glass pane 2.

In a second step S2, a reflective element 6 is provided, the reflective element 6 comprising an optically high refractive thin glass plate 7 having an outer side surface V, an inner side surface VI, a thickness of 20 μm to 500 μm and a refractive index of 1.9 or more, and an optically low refractive layer 8 having a refractive index of 1.6 or less applied on the inner side surface VI of the optically high refractive thin glass plate 7.

In a third step S3, the outer side surface V of the optically high refractive thin glass sheet 7 of the reflective element 6 is bonded via the adhesive layer 5 to the inner side surface IV of the inner layer glass sheet 2 of composite material to form the composite glass sheet 100 such that the reflective element 6 is arranged in a region of the composite glass sheet 100 which, when viewed perpendicularly through the composite glass sheet 100, is entirely located in the region in which the masking layer 4 is arranged.

Steps S1 and S2 may also be performed in reverse order or simultaneously. Step S3 is preferably performed after steps S1 and S2, but may also be performed simultaneously with steps S1 and S2.

The present invention is explained hereinafter with examples and comparative examples. The reflective properties of the composite glass sheet according to the invention and the composite glass sheet not according to the invention for p-polarized light are compared hereinafter.

The layer sequences, layer thicknesses and refractive indices according to comparative examples C and D and examples E, F, G, H and J according to the invention are shown in tables 1 and 2.

To simulate masking layers, dark outer glass sheets 1 and dark PVB were used as thermoplastic interlayers 3 in comparative examples C and D and examples E, F, G, H and J according to the present invention.

TABLE 1

TABLE 2

In example G, siO is used ₂ Is nano porous SiO ₂ 。

The reflectivity of p-polarized light, which is critical to image quality, is called RL (a) p-pol. Reflectivity describes the proportion of total incident p-polarized radiation that is reflected. It shows no number of units (normalized to the incident radiation) of 0 to 1. Plotted as a function of wavelength, which forms a reflectance spectrum. The data of the reflectivity are based on reflectance measurements with the light source of the light emitting device a, which emits with a normalized radiation intensity of 1 in the spectral range of 380nm to 780 nm. The respective reflection spectra of the comparative examples and examples at the incident angles of 60 °, 65 °, 70 ° and 75 ° are shown in fig. 15 to 18.

As can be seen from fig. 15 to 18, since the fingerprint acts as an additional interference layer, the reflection spectrum of comparative example D is significantly shifted to a higher wavelength than that of comparative example C. Thus, the image quality of the composite glass sheet according to comparative example D was significantly reduced as compared to the image quality of the composite glass sheet according to comparative example C. In contrast, the reflectance spectrum of embodiment F is shifted to a higher wavelength by a smaller extent than that of comparative examples C and D, as compared with that of embodiment E. Also, the reflectance spectrum of example J is shifted to a higher wavelength by a smaller extent than that of comparative examples C and D, as compared with the reflectance spectrum of example H. Thus, the fingerprint on the reflective element of the composite glass sheet according to the present invention causes less variation in the reflection spectrum than the fingerprint on the reflective layer of the composite glass sheet according to comparative example C, which comprises an optical high refractive coating and an optical low refractive coating. Thus, the fingerprint on the composite glass sheet according to the invention is less visible. This is an advantage of the composite glass sheet according to the invention. As can be seen from fig. 15 to 18, although the absolute reflection intensity is lower in the embodiments E, F, G, H and J, the reflection spectrum is smoother as compared with the comparative examples C and D. In embodiments E, F, G, H and J, the wavelength dependence of the reflectance is less pronounced, facilitating color neutrality of the reflected image. The composite glass sheets according to embodiments E, F, G, H and J thus have a particularly uniform reflectance spectrum. This is another advantage of the composite glass sheet according to the invention.

List of reference numerals

100. Composite glass plate

101. Projection assembly

1. Outer layer glass plate

2. Inner glass plate

3. Thermoplastic interlayers

4. Masking layer

5. Adhesive layer

6. Reflection element

7. Optical high refraction thin glass plate

8. Optical low refractive layer

9 HUD reflective layer

10. Image forming unit

Upper edge of O-composite glass sheet 100

Lower edge of U-shaped composite glass sheet 100

Side edges of S-composite glass sheet 100

I outer glass pane 1 outer surface

II inner side surface of outer glass sheet 1

III the outside surface of the inner glass pane 2

Inner side surface of IV inner glass sheet 2

Outside surface of V-optical high refractive thin glass plate 7

Inner side surface of VI optical high refractive thin glass plate 7

The region in which the a masking layer 4 is arranged

B regions in which the reflective elements 6 are arranged

X' -X section line

Y-Y' section line

Claims

1. A composite glass sheet (100) comprising at least:

an outer glass pane (1) having an outer side surface (I) and an inner side surface (II),

a thermoplastic intermediate layer (3),

an inner glass pane (2) having an outer side surface (III) and an inner side surface (IV),

-a masking layer (4),

an adhesive layer (5),

a reflective element (6) comprising an optically high refractive thin glass plate (7) having an outer side surface (V), an inner side surface (VI), a thickness of 20 μm to 500 μm and a refractive index of 1.9 or more, and an optically low refractive layer (8) having a refractive index of 1.6 or less arranged on the inner side surface (V1) of the optically high refractive thin glass plate (7),

Wherein the thermoplastic interlayer (3) is arranged between the outer glass pane (1) and the inner glass pane (2),

the masking layer (4) is arranged between the outer glass pane (1) and the inner glass pane (2) or on the inner surface (IV) of the inner glass pane (2) in one region of the composite glass pane (100),

the adhesive layer (5) is arranged between the inner glass pane (2) and the reflective element (6),

the outer side surface (V) of the optically high refractive thin glass plate (7) is bonded to the inner side surface (IV) of the inner glass plate (2) via an adhesive layer (5),

and the reflective element (6) is arranged in a region of the composite glass sheet (100) which, when viewed perpendicularly through the composite glass sheet (100), is located entirely in the region in which the masking layer (4) is arranged.

2. The composite glass sheet (100) according to claim 1, wherein the optically high refractive thin glass sheet (7) has a thickness of 50 μm to 300 μm, preferably 50 μm to 200 μm.

3. The composite glass pane (100) according to claim 1 or 2, wherein the refractive index of the optically high refractive thin glass pane (7) is at least 2.0, preferably at least 2.1, particularly preferably at least 2.3.

4. A composite glass sheet (100) according to one of claims 1 to 3, wherein the optically high refractive thin glass sheet (7) contains a dopant with lead, barium or lanthanum.

5. The composite glass pane (100) according to one of claims 1 to 4, wherein the refractive index of the optically low refractive layer (8) is at most 1.5, preferably at most 1.4.

6. The composite glass pane (100) according to one of claims 1 to 5, wherein the optical low-refractive layer (8) is formed on the basis of silicon dioxide, doped silicon oxide, magnesium fluoride or calcium fluoride.

7. The composite glass pane (100) according to one of claims 1 to 6, wherein the optical low-refractive layer (8) has a thickness of 50nm to 200nm, preferably 100nm to 150nm, in particular 120 nm.

8. The composite glass pane (100) according to one of claims 1 to 7, wherein the masking layer (4) is embodied circumferentially in a frame-like manner and has a greater width, in particular in the portion overlapping the reflective element (6), than in the portion differing therefrom.

9. The composite glass pane (100) according to one of claims 1 to 8, wherein the masking layer (4) is implemented as an opaque masking print arranged on the inner side surface (II) of the outer glass pane (1), the outer side surface (III) of the inner glass pane (2), or the inner side surface (IV) of the inner glass pane (2), or as an opaque colored region of the thermoplastic interlayer (3).

10. The composite glass pane (100) according to one of claims 1 to 9, wherein the HUD reflecting layer (9) is arranged between the outer glass pane (1) and the inner glass pane (2).

11. Projection assembly (101), comprising at least:

composite glass pane (100) according to one of claims 1 to 10,

an imaging unit (10) which is aligned with the reflective element (6) and emits p-polarized light,

wherein the inner side surface (IV) of the inner glass sheet (2) is the surface of the inner glass sheet (2) closest to the imaging unit (10).

12. Projection assembly (101) according to claim 11, wherein the reflective element (6) reflects at least 3%, preferably at least 4%, particularly preferably at least 6%, most particularly preferably at least 10% of p-polarized light incident on the reflective element (6) within a wavelength range of 400nm to 700nm and an angle of incidence of 62 ° to 77 °.

13. Projection assembly (101) according to claim 11 or 12, wherein the imaging unit (10) is a display, preferably an LCD display, an LED display, an OLED display or an electroluminescent display, particularly preferably an LCD display, and p-polarized light (7) preferably impinges the composite glass sheet (10) at an angle of incidence of 55 ° to 80 °, particularly preferably 62 ° to 77 °.

14. Method of manufacturing a composite glass sheet (100) according to one of claims 1 to 10, comprising at least:

a) Providing a composite of an outer glass pane (1) having an outer side surface (I) and an inner side surface (II), a thermoplastic interlayer (3) and an inner glass pane (2) having an outer side surface (III) and an inner side surface (IV), wherein the thermoplastic interlayer (3) is arranged between the outer glass pane (1) and the inner glass pane (2) and the masking layer (4) is arranged in one region between the outer glass pane (1) and the inner glass pane (2) or on the inner side surface (IV) of the inner glass pane (2);

b) Providing a reflective element (6), the reflective element (6) comprising an optically high refractive thin glass plate (7) having an outer side surface (V), an inner side surface (VI), a thickness of 20 μm to 500 μm and a refractive index of 1.9 or more, and an optically low refractive layer (8) having a refractive index of 1.6 or less applied on the inner side surface (VI) of the optically high refractive thin glass plate (7);

c) -joining an outer side surface (V) of the optically high refractive thin glass sheet (7) to an inner side surface (IV) of an inner layer glass sheet (2) of the composite material via an adhesive layer (5) to form a composite glass sheet (100) such that the reflective element (6) is arranged in a region of the composite glass sheet (100) which is entirely located in a region in which a masking layer (4) is arranged when viewed perpendicularly through the composite glass sheet (100).

15. Use of a composite glass pane (100) according to one of claims 1 to 10 as a vehicle glass pane in a movement pattern for traveling on land, in the air or on water, in particular in a motor vehicle, and in particular as a windscreen for a head-up display.