Composite pane with hologram element and an optically high-refractive layer

Abstract

The invention relates to a composite pane (100), at least comprising an outer pane (1) with an outer-side surface (I) and an interior-side surface (II), an inner pane (2) with an outer-side surface (III) and an interior-side surface (IV), a first intermediate layer (3) and a hologram element (4) with at least one hologram, wherein the first intermediate layer (3) is arranged between the outer pane (1) and the inner pane (2), the hologram element (4) is arranged between the outer pane (1) and the first intermediate layer (3) or between the inner pane (2) and the first intermediate layer (3), and wherein an optically high-refractive layer (6) is arranged on the interior-side surface (IV) of the inner pane (2). The invention also relates to a projection arrangement comprising a composite pane of this type, to a method for producing such a composite pane and to its use.

Description

[0001] Composite pane with hologram element and an optically highly refractive layer

[0002] The invention relates to a composite pane with a hologram element and an optically highly refractive coating, a method for producing such a composite pane, and the use of such a composite pane.

[0003] Laminated glass is used in many places today, especially in vehicle construction. The term "vehicle" encompasses, among other things, road vehicles, aircraft, ships, agricultural machinery, and even work equipment.

[0004] Laminated glass is also used in other areas, such as building glazing or information displays, e.g., in museums or as advertising displays.

[0005] Laminated glass is also frequently used as a head-up display (HUD) for information. An imaging unit projects an image onto the laminated glass panes to display information in the viewer's field of vision. In the automotive sector, the imaging unit is positioned, for example, on the dashboard, so that the projected image is reflected toward the viewer on the nearest glass surface of the laminated glass pane, which is tilted toward the viewer (see, for example, European patent EP 0 420 228 B1 or German patent application DE 10 2012 211 729 A1).

[0006] Head-up displays, in which the projected image is reflected toward the viewer on the nearest glass surface of the laminated glass pane tilted toward the viewer, are subject to the law of reflection, according to which the angle of incidence and the angle of emission are equal. The angle of inclination of the laminated glass pane cannot therefore be freely selected. Hologram elements laminated between the panes of a laminated glass pane can also be used for head-up displays. The hologram element has at least one hologram, and the hologram can contain recorded information. The hologram can be activated by light emitted by a projector, thus displaying the information recorded in the hologram for the viewer.Head-up displays based on the principle of holography, so-called holographic head-up displays, are disclosed, for example, in the publications WO 2012 / 156124 A1, US 2019 / 0056596 A1, US 10,394,032 B2, US 10,061,069 B2 and US 2015 / 205138 A1.

[0007] DE 10 2020 112 447 A1 discloses a method for integrating a hologram in a rigid component of a predetermined target surface geometry using a hologram receiving layer made of a liquid photopolymer.

[0008] A hologram can be created in a holographic material, i.e. a photosensitive material, which is laminated between the panes of a composite pane. To record a hologram, two mutually coherent light beams, the so-called reference beam, which can also be called the reference wave, and the so-called object beam, which can also be called the object wave, are directed onto a holographic material. The resulting interference pattern of the superimposed wavefronts is written into the holographic material as an alternating refractive index modulation. If the reference wave and the object wave have parallel wavefronts, the interference pattern corresponds to a parallel grating whose lamellae are angled at the bisector of the reference wave and the object wave. After recording, the holographic material is cured, whereby it loses the ability to record further holograms.If the holographic material in which the hologram was recorded is illuminated again with the reference wave, the light is diffracted at the recorded grating of the hologram in such a way that the diffracted wave corresponds to the object wave. By illuminating the interference pattern written into the holographic material with the reference wave, the object wave can be reconstructed.

[0009] Head-up displays, in which the projected image is projected toward the viewer via a hologram, thus enable the production of laminated panels with laminated holograms where the angle of incidence onto the laminated panel is not as large as the angle of emission. Consequently, the angle of inclination of the laminated panel can be chosen more freely in holographic head-up displays.

[0010] When producing a laminated display with a hologram, it is advantageous to record the hologram in the holographic material of a hologram element precursor only after the lamination process, since the lamination process can have a negative impact on the optical properties of a recorded hologram. A method for producing a laminated holographic display in which the hologram is recorded only after lamination is disclosed, for example, in EP 3 461 636 B1.

[0011] However, recording a hologram into the holographic material of a hologram element precursor laminated between two glass panes is problematic, as any change in the refractive index causes reflections of the object beam and the reference beam during hologram recording. Unwanted reflections on the surfaces of the two glass panes facing away from the holographic material lead to unwanted interference patterns and thus to unwanted gratings recorded in the holographic material. These unwanted recorded gratings cause the hologram to display unwanted artifacts upon irradiation with the reference wave after the holographic material has hardened. Furthermore, external light sources can activate the unwanted gratings recorded in the hologram.This leads to unnecessary distractions and possibly glare for the viewer and should therefore be minimized for safety reasons.

[0012] In the context of the present application, the term "hologram element precursor" refers to the precursor of a hologram element. A hologram element precursor does not have a hologram. A hologram element is obtained by recording at least one hologram by exposing the holographic material of a hologram element precursor to an object beam and a reference beam. The resulting hologram element differs from the hologram element precursor in that at least one hologram is recorded in the hologram element. WO 2021 / 087286 A1 discloses a replication tool for use in producing a holographic film by replication and a method for producing a laminated glazing using the replication tool.During replication, an oil or gel with a matching refractive index can be placed in a cavity between the laminated glazing and the main holographic film assembly to reduce reflections during replication and improve the quality of the laminated glazing.

[0013] US 2019 / 101865 A1 discloses a method for producing a laminated holographic display, wherein a display precursor is first provided. The display precursor comprises a first glass layer, a second glass layer, an unexposed photopolymer film layer disposed between the first glass layer and the second glass layer, and a polymer layer disposed between the second glass layer and the unexposed photopolymer film layer.

[0014] WO 2022 / 053404 A1 discloses a method for producing a composite pane with a hologram, wherein a photosensitive material is applied as a hologram element in a coating area on the surface of a first pane, a hologram is generated in the hologram element by selective laser irradiation, and the first pane with a hologram is laminated to a second pane to form the composite pane.

[0015] WO 2021 / 209201 A1 discloses a projection arrangement for a head-up display (HUD) comprising a composite pane with a HUD region and a HUD projector that emits p-polarized radiation. The composite pane comprises an outer pane and an inner pane, which are connected to one another via an intermediate layer. A high-index sol-gel coating with a refractive index of at least 1.7 is applied to the surface of the inner pane facing away from the intermediate layer.

[0016] EP 0536763 B1 discloses a composite pane integrated into a projection arrangement comprising a hologram. A light beam emitted by a light source passes through a liquid crystal panel, projects the information displayed on the liquid crystal panel onto a mirror, and the information is reflected by the mirror onto the composite pane with the hologram. The light beam incident on the hologram is diffracted and reflected by the pattern of the hologram element. The light beam resulting from the diffraction exits the hologram element, strikes a film of a windshield, is reflected by the film toward the driver, and is perceived as an image. The hologram is thus not incorporated into the windshield itself, but into an additional pane mounted in the vehicle interior.

[0017] While in head-up displays, in which the projected image is reproduced towards the viewer by means of a hologram, a reflection of the reference wave on the outside surface of the outer pane is attenuated as a result of diffraction at the recorded grating of the hologram, a reflection of the reference wave on the inside surface of the inner pane can appear as a weak but nevertheless disturbing ghost image. If the light emitted by a projector and incident on the composite pane at the Brewster angle (incident) is exclusively p-polarized, the reflected portion of the light at the Brewster angle is close to zero. The Brewster angle is determined by the difference in the refractive indices between two media. The refractive index of a typical composite pane with a holographic medium is approximately 1.5.If the external medium is air, as is usually the case, with a refractive index of 1, the Brewster angle is approximately 56°. If minimal reflection, i.e., light incidence as close as possible to the Brewster angle, is to be achieved, the degree of freedom in positioning a projector, for example, relative to the projection surface—for example, a windshield with a HUD function—is significantly limited.

[0018] The present invention is based on the object, particularly for a head-up display, of providing an improved composite pane with a hologram element, in which the tilt angle of the composite pane can be selected more freely, particularly shifted to larger tilt angles, while maintaining good image quality, while simultaneously minimizing the occurrence of unwanted ghost images and artifacts in the composite pane. Furthermore, the composite pane should be easy and cost-effective to manufacture, even in industrial series production.

[0019] The object of the present invention is achieved by a composite pane according to independent claim 1. Preferred embodiments are set out in the subclaims. A method for producing a composite pane according to the invention and its use are set out in further independent claims.

[0020] The invention relates to a composite pane comprising at least an outer pane with an outer surface and an inner surface, an inner pane with an outer surface and an inner surface, a first intermediate layer and a hologram element with at least one hologram.

[0021] The composite window is a vehicle window, which means that it is suitable for installation in a vehicle, whereby the vehicle window, when installed, separates the vehicle interior from the surroundings.

[0022] The outer pane, also referred to as the first pane, represents the pane of the laminated pane that is adjacent to the vehicle's surroundings when the laminated pane is installed. The outer pane has an outer surface, also referred to as side I, that points towards and adjoins the vehicle's surroundings. The surface of the outer pane opposite the outer surface of the outer pane is referred to as the interior surface, also referred to as side II, of the outer pane and faces the vehicle's interior when the glazing is installed. The inner pane, also referred to as the second pane, represents the pane of the laminated pane that faces the vehicle interior when installed in a vehicle. The inner pane has an outer surface, also referred to as side III, which faces the outer pane and the vehicle's surroundings when installed.The surface of the inner pane opposite the outer surface of the inner pane is referred to as the interior surface of the inner pane, also called side IV, and borders on the vehicle interior when installed.

[0023] The first intermediate layer is arranged between the outer pane and the inner pane, and the hologram element is arranged between the outer pane and the first intermediate layer or between the inner pane and the first intermediate layer. The first intermediate layer, as well as optionally present additional intermediate layers, connect the first pane and the second pane to each other.

[0024] According to the invention, precisely one optically highly refractive, preferably transparent, layer is arranged on the interior-side surface of the inner pane (side IV). Preferably transparent in the sense of the invention means that the optically highly refractive layer is preferably permeable to light in the visible range of the light spectrum from 380 nm to 780 nm. Particularly preferably, the optically highly refractive layer has a transmission of at least 70% in the visible range of the light spectrum. This optically highly refractive layer advantageously makes it possible to select the angle of inclination of the composite pane in a projection arrangement more freely, in particular to shift it towards larger Brewster angles. This makes it possible to largely avoid artifacts and ghost images caused by reflected components of the light, even with steeper installation positions of the composite pane, as is the case, for example, in trucks or tractors.

[0025] The optically high-refractive-index layer is also referred to below as an HI layer or HI coating, where HI stands for high index. According to the invention, exactly one HI layer is applied directly to the interior-facing surface (inside / side IV) of the inner pane. This is mandatory at least in the area of ​​the composite pane that is intended to serve as a projection surface in a projection system. Thus, the HI layer forms the outer surface of the composite pane according to the invention, facing the interior.

[0026] According to the invention, the optically high-refractive-index layer (HI layer) has a refractive index of greater than or equal to 2.

[0027] In the context of the present invention, refractive indices are generally specified relative to a wavelength of 550 nm. The refractive index can be determined, for example, by means of ellipsometry. Ellipsometers are commercially available, for example from Sentech. The refractive index of a dielectric layer is preferably determined by first depositing it as a single layer on a substrate and then measuring the refractive index by means of ellipsometry. To determine the refractive index of a dielectric layer sequence, the layers of the layer sequence are each deposited individually as individual layers on a substrate, and then the refractive index is determined by means of ellipsometry. According to the invention, a refractive index of at least 2 is to be achieved for each of these individual layers.Dielectric layers with a refractive index of at least 2 and methods for their deposition are known to those skilled in the art in the field of thin films. Physical vapor deposition methods, particularly magnetron sputtering, are preferred.

[0028] The composite pane is a vehicle window. Thus, the hologram element is directly integrated into the vehicle glazing, and no additional composite panes with a hologram are required in the beam path of the projector of a projection arrangement. Preferably, the composite pane is a windshield in which the hologram element is directly integrated. In a preferred embodiment, the HI coating on the interior-facing surface of the inner pane is based on silicon nitride, tin-zinc oxide, silicon zirconium nitride, silicon titanium nitride, silicon hafnium nitride, or titanium oxide, particularly preferably based on silicon zirconium nitride or titanium oxide (TiOx). These materials have proven particularly advantageous for increasing the Brewster angle.

[0029] The optically highly refractive layer with a refractive index greater than or equal to 2 is formed as a coating, preferably based on silicon nitride, zinc tin oxide, silicon zirconium nitride or titanium oxide (TiOx).

[0030] According to the invention, the phrase "based on..." means that the HI coating consists of the material mentioned or consists essentially of it, along with any customary impurities or dopants. According to the invention, the HI layer is formed of this material to the extent of more than 95 wt.%, preferably more than 97 wt.%, for example 98 wt.% of the HI layer. The materials mentioned for the HI layer can be undoped or doped, for example, with transition metal oxides such as ZnO, ZrO2, HfOx.

[0031] In one embodiment of the invention, the optically highly refractive layer is formed with a layer thickness of 10 nm to 100 nm, preferably of 20 nm to 80 nm, particularly preferably of 50 nm to 70 nm.

[0032] The outer pane and the inner pane each have an outside surface, i.e., an outer surface, and an inside surface, i.e., an inside surface, and a circumferential side edge extending therebetween. For the purposes of the invention, the term "outside surface" refers to the main surface intended to face the outside environment in the installed position. For the purposes of the invention, the term "inside surface" refers to the main surface intended to face the interior in the installed position. The inside surface of the outer pane and the outside surface of the inner pane face each other in the composite pane according to the invention. The surfaces of the glass panes are typically designated as follows:

[0033] The outside surface of the outer pane is called Side I. The inside surface of the outer pane is called Side II. The outside surface of the inner pane is called Side III. The inside surface of the inner pane is called Side IV.

[0034] The composite pane is designed to separate an interior space from the exterior environment in a window opening of a vehicle. Within the meaning of the invention, the "inner pane" refers to the pane facing the interior (vehicle interior). The "outer pane" refers to the pane facing the exterior environment.

[0035] The hologram element refers to the holographic medium containing the hologram. The hologram element comprises a photosensitive material, i.e., a holographic material. A hologram can be recorded in this material by exposure to a suitable light source. In the finished composite pane, the material of the hologram element is no longer light-sensitive, as the holographic material is altered during the process to such an extent that further recording of a hologram is no longer possible.

[0036] The hologram element comprises a holographic material and can optionally additionally comprise a first substrate layer and / or a second substrate layer. Suitable holographic materials are known to those skilled in the art. Suitable first and second substrate layers are also known to those skilled in the art.

[0037] The hologram element preferably comprises a photopolymer, dichromate gelatin or silver halide gelatin as holographic material, particularly preferably a photopolymer.

[0038] Silver halides or dichromates are typically used in a gelatin matrix, which is first dried at room temperature before a hologram can be recorded by exposure. In a first preferred embodiment, the holographic material is formed as a coating on the interior surface of the outer pane or as a coating on the exterior surface of the inner pane.

[0039] The composite pane may additionally comprise a second intermediate layer. In a second preferred embodiment of the composite pane according to the invention, the hologram element is arranged between the first intermediate layer and the inner pane, and an additional second intermediate layer is arranged between the inner pane and the hologram element.

[0040] In a preferred embodiment, the hologram element comprises a holographic material, a first substrate layer, and a second substrate layer, wherein the holographic material is arranged between the first intermediate layer and the inner pane, a second intermediate layer is arranged between the holographic material and the inner pane, the first substrate layer is arranged between the holographic material and the first intermediate layer, and the second substrate layer is arranged between the holographic material and the second intermediate layer. Consequently, in this embodiment, the holographic material is arranged between a first substrate layer and a second substrate layer.

[0041] In a further embodiment, the hologram element comprises a first substrate layer and a holographic material.

[0042] In this embodiment, the composite pane can also optionally comprise a second intermediate layer. If a second intermediate layer is present, it is arranged between the inner pane and the hologram element, and the first intermediate layer is arranged between the outer pane and the hologram element. The intermediate layers can independently be a thermoplastic intermediate layer, an adhesive layer, or an optically clear adhesive.

[0043] The first intermediate layer is preferably a thermoplastic intermediate layer, an adhesive layer or an optically clear adhesive (OCA).

[0044] The second intermediate layer is preferably a thermoplastic intermediate layer, an adhesive layer or an optically clear adhesive (OCA).

[0045] An optically clear adhesive (OCA) is characterized by high light transmission, low haze, no double refraction, high UV resistance, and good aging resistance. This prevents uncontrolled and therefore undesirable impairment of light transmission or unsightly distortions.

[0046] The adhesive layer preferably has an absorption in the visible spectral range of less than 5%, in particular less than 2% or even 1% and preferably a turbidity of less than 5%, in particular less than 2% or even less than 1%.

[0047] The adhesive layer is preferably formed as a homogeneous layer.

[0048] The adhesive layer preferably has a thickness of 20 μm to 200 μm, more preferably 50 μm to 150 μm, and most preferably 60 μm to 100 μm. This achieves good optical properties. Adhesive layers with these thicknesses are also commercially available as adhesive films. The adhesive of the adhesive layer can alternatively also be used as a liquid adhesive. The adhesive of the adhesive layer is preferably a chemically acting, in particular chemically curing, or UV-curing adhesive, particularly preferably an acrylate adhesive or a silicone-based adhesive.

[0049] The first substrate layer contains, for example, polyamide (PA), polycarbonate (PC), cellulose triacetate (TAC), and / or polyethylene terephthalate (PET). The first substrate layer is, for example, 35 pm (micrometers) to 60 pm thick.

[0050] The second substrate layer contains, for example, polyamide (PA), polycarbonate (PC), cellulose triacetate (TAC), and / or polyethylene terephthalate (PET). The second substrate layer is, for example, 35 pm (micrometers) to 60 pm thick.

[0051] The materials mentioned for the substrate layer are advantageously suitable for reducing or preventing the diffusion of plasticizers.

[0052] As described above, in a preferred embodiment, the holographic material comprises a photopolymer. The photopolymer is, for example, 10 pm to 100 pm thick, for example 16 pm. Suitable photopolymers are known to those skilled in the art. The photopolymer preferably comprises crosslinked polyurethane (PU). Alternatively, a liquid photopolymer can also be used.

[0053] In one embodiment, a UV protective layer is arranged between the outer pane and the holographic material in the composite pane according to the invention. Such a UV protective layer prevents aging processes of the holograms recorded in the holographic material caused by external UV radiation.

[0054] The outer pane and the inner pane are made of glass, particularly preferably soda-lime glass, as is common for window panes. The outer pane and the inner pane can also be made of other types of glass, such as quartz glass, borosilicate glass, or alumino-silicate glass, or of rigid, clear plastics, such as polycarbonate or polymethyl methacrylate. The outer pane and the inner pane can be clear, independently of one another, or tinted or colored. Composite panes designed as windshields must have sufficient light transmission in the central viewing area, preferably at least 70% in the main viewing area A according to ECE-R43. The outer pane and the inner pane are preferably curved, i.e. they have a bend.

[0055] The outer pane and / or the outer side (side III) of the inner pane may have suitable coatings known per se, for example non-stick coatings, anti-scratch coatings on the outside of the outer pane, heatable coatings, sun protection coatings or low-E coatings.

[0056] A first intermediate layer or second intermediate layer formed as a thermoplastic intermediate layer preferably contains or consists of at least polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), polyurethane (PU) or copolymers or derivatives thereof, particularly preferably polyvinyl butyral (PVB), very particularly preferably polyvinyl butyral (PVB) and additives known to the person skilled in the art, such as plasticizers.

[0057] Preferably, a first intermediate layer or second intermediate layer formed as a thermoplastic intermediate layer contains at least 60 wt.%, particularly preferably at least 70 wt.%, in particular at least 90 wt.% and for example at least 97 wt.% polyvinyl butyral.

[0058] A first intermediate layer formed as a thermoplastic intermediate layer can be formed by a single film or by more than one film.

[0059] A second intermediate layer formed as a thermoplastic intermediate layer can also be formed by a single film or by more than one film.

[0060] The first intermediate layer and, if present, the second intermediate layer can also independently of one another be a functional intermediate layer, in particular an intermediate layer with acoustically dampening properties, an infrared-reflecting intermediate layer, an infrared-absorbing intermediate layer, a UV-absorbing intermediate layer, an at least partially colored intermediate layer, and / or an at least partially tinted intermediate layer. Thus, the first intermediate layer and, if present, the second intermediate layer can independently of one another also be, for example, a bandpass filter film.

[0061] The thickness of a first intermediate layer or second intermediate layer formed as a thermoplastic intermediate layer is between 30 pm and 1500 pm, preferably between 50 pm and 780 pm, preferably 350 pm and 760 pm, for example 380 pm or 760 pm.

[0062] The hologram element preferably has a thickness of 5 pm to 500 pm, preferably of 10 pm to 200 pm and particularly preferably of 15 pm to 150 pm.

[0063] The thickness of the outer and inner panes can vary widely and thus be adapted to the requirements of each individual case. The outer and inner panes preferably have thicknesses of 0.5 mm to 5 mm, particularly preferably 1 mm to 3 mm.

[0064] 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 be, in particular, an intermediate layer with acoustic damping properties, an infrared-reflecting intermediate layer, an infrared-absorbing intermediate layer, an at least partially colored intermediate layer, and / or an at least partially tinted intermediate layer. If several additional intermediate layers are present, these can also have different functions.

[0065] A composite pane according to the invention can additionally comprise a masking print, in particular made of a dark, preferably black, enamel. The masking print is in particular a peripheral, i.e., frame-like, masking print. The peripheral masking print primarily serves as UV protection for the assembly adhesive of the composite pane. The masking print can be opaque and full-surface. The masking print can also be semi-transparent, at least in sections, for example, as a dot matrix, striped matrix, or checkered matrix. Alternatively, the masking print can also have a gradient, for example, from an opaque covering to a semi-transparent covering.

[0066] The hologram element preferably does not extend to the edge of the pane, while the first intermediate layer extends to the edge of the pane. In this embodiment, the hologram element in the composite pane is sealed at its peripheral edge by the first intermediate layer or additional layers arranged there, thus protecting it from external influences such as moisture and cleaning agents. Furthermore, the diffusion of plasticizers from the hologram element can be reduced or prevented.

[0067] If the hologram element is not arranged over the entire surface of the pane, a barrier film with a cutout is preferably arranged in a frame around the hologram element. The cutout corresponds to the area in which the hologram element is arranged. The hologram element is arranged within this cutout and fills it completely. The barrier film has the shape of a circumferential frame and is in direct contact with the circumferential edge of the hologram element. The hologram element and the barrier film thus lie in the same plane and touch along their edges, with their contact surface being essentially orthogonal to the pane surfaces of the composite pane. The barrier film in the form of a circumferential frame compensates for a local difference in thickness between the area with the hologram element and the surrounding area in the composite pane according to the invention.According to the invention, the barrier film is not applied overlapping the hologram element, but only in its immediate vicinity, adjacent to the surrounding edge of the hologram element, thus enabling this compensation of thickness differences. The laminated pane with the hologram element therefore not only exhibits improved aging resistance, but also improved durability by minimizing stress and glass breakage.

[0068] The barrier film is preferably a polymer layer and preferably contains polyvinyl butyral (PVB), polyethylene terephthalate (PET), polyamide (PA), polyethylene (PE), polymethyl methacrylate (PMMA), polycarbonate (PC), polyvinyl chloride (PVC), cellulose triacetate (TAC) or consists essentially thereof.

[0069] The laminated glass according to the invention is preferably curved in one or more directions of space, as is common for motor vehicle windows, with typical radii of curvature ranging from approximately 10 cm to approximately 40 m. However, the laminated glass can also be flat, for example, if it is intended as a window for buses, trains, or tractors.

[0070] A composite pane according to the invention has an upper edge and a lower edge, as well as two side edges running between the upper and lower edges. The upper edge refers to the edge intended to face upwards in the installed position. The lower edge refers to the edge intended to face downwards in the installed position. The upper edge is often referred to as the roof edge, and the lower edge is often referred to as the engine edge.

[0071] Laminated glass units used as windshields have a central field of vision whose optical quality is subject to high demands. This central field of vision must have high light transmission (typically greater than 70%). This central field of vision is, in particular, the field of vision referred to by experts as field of vision B, field of vision B, or zone B. Field of vision B and its technical requirements are specified in Regulation No. 43 of the Economic Commission for Europe of the United Nations (UN / ECE) (ECE-R43, "Uniform Provisions Concerning the Approval of Safety Glazing Materials and their Installation on Vehicles"). Field of vision B is defined in Annex 18.

[0072] The hologram element is advantageously arranged within the central field of view (field of view B) in a composite pane designed as a windshield. The hologram element can, but does not have to, cover the entire area and can also protrude beyond it. The hologram element preferably extends over at least 30%, particularly preferably over at least 50%, furthermore particularly preferably over at least 80% of the pane. This makes it possible to avoid visible transitions between the hologram element and a section without a hologram element in the visible area of ​​the pane. The hologram element is particularly preferably arranged such that the peripheral edge of the hologram element is located in the area of ​​an opaque cover print. This has the advantage that the opaque cover print conceals the transition from the hologram element to the surrounding layer.The masking print is usually located at the edge of the pane and obscures the view of attachments or adhesives. Windshields typically have a peripheral masking print made of opaque enamel, which serves primarily to protect the adhesive used to install the pane from UV radiation and to visually conceal it. This peripheral masking print is preferably used to also conceal the peripheral edge of the hologram element. Preferably, both the outer pane and the inner pane of the laminated pane have a masking print, so that visibility in the edge area is obstructed from both sides.

[0073] The hologram element may also have cutouts or holes, for example, in the area of ​​so-called sensor windows or camera windows. These areas are intended for the installation of sensors or cameras whose function could be impaired by a hologram element in the beam path.

[0074] The hologram element is preferably arranged across the entire width and height of the composite pane, particularly preferably minus a peripheral edge region with a width of, for example, 5 mm to 50 mm. The hologram element is thus protected from contact with the ambient atmosphere and corrosion. The width of the peripheral edge region can be constant or vary.

[0075] The laminated pane can be, for example, the windshield or roof window of a vehicle or other vehicle glazing, for example in a motor vehicle, rail vehicle or bus.

[0076] The invention also encompasses a projection arrangement for displaying information to a viewer, comprising at least one composite pane according to the invention and a projector directed from the inside, i.e., from a vehicle interior, onto the hologram element on side IV. The composite pane according to the invention can be designed as described above in the various embodiments.

[0077] The projector of the projection arrangement emits light at wavelengths to which the hologram, or if there is more than one hologram, the holograms of the hologram element, respond.

[0078] In the projection arrangement according to the invention, unwanted reflection of the light emitted by the projector on the interior-facing surface of the inner pane of the composite pane is minimized by the HI coating. Advantageously, the Brewster angle, at which the reflected portion of the light is minimized, particularly for p-polarized light, is close to zero, can be shifted toward higher angles and selected more freely.

[0079] The invention also relates to a method for producing a composite pane, wherein at least: a) an outer pane having an outer surface and an inner surface, a first intermediate layer, a hologram element having at least one hologram and an inner pane having an outer surface and an inner surface and an HI coating applied to the inner surface are provided, b) a layer stack is formed in which the first intermediate layer is arranged between the outer pane and the inner pane and the hologram element is arranged between the outer pane and the first intermediate layer or between the inner pane and the first intermediate layer, c) the layer stack is connected by lamination.

[0080] The hologram element can contain, for example, dichromate gelatin or silver halide gelatin or a photopolymer as holographic material as described above. In the embodiment of the method according to the invention described above, the optically highly refractive layer is applied to the interior-side surface of the inner pane before lamination.

[0081] Alternatively, it is also possible to apply the optically highly refractive coating only after lamination on the interior surface of the inner pane (side IV), so that an uncoated inner pane is initially provided in step a).

[0082] The invention therefore also relates to a method for producing a composite pane, wherein at least: a) an outer pane having an outer surface and an interior surface, a first intermediate layer, a hologram element having at least one hologram and an inner pane having an outer surface and an interior surface are provided, b) a layer stack is formed in which the first intermediate layer is arranged between the outer pane and the inner pane and the hologram element is arranged between the outer pane and the first intermediate layer or between the inner pane and the first intermediate layer, c) the layer stack is connected by lamination, d) an optically highly refractive layer is applied to the interior surface of the inner pane.

[0083] The application of the optically highly refractive layer can be achieved, for example, by established processes such as wet coating, magnetron sputtering or chemical (CVD) or physical vapor deposition (PVD) processes on the interior surface of the inner pane.

[0084] Advantageously, the integration of such a coating into the industrial series production of composite panes can be carried out easily and cost-effectively.

[0085] It is understood that in step a), instead of a hologram element in which at least one hologram is recorded, an unexposed hologram element precursor made of light-sensitive material can alternatively be provided. Thus, in step b), the formation of the layer stack and, in step c), the lamination can also take place with the unexposed hologram element precursor or with the final hologram element with a recorded hologram element. It is understood that, when the unexposed hologram element precursor is provided in step a), a method according to the invention comprises, as an additional step after the lamination of the layer stack, the recording of at least one hologram in the hologram element precursor.

[0086] The lamination of the layer stack is preferably carried out under the influence of heat, vacuum and / or pressure. Known lamination methods can be used, for example, autoclave processes, vacuum bag processes, vacuum ring processes,

[0087] Calendering processes, vacuum laminators or combinations thereof.

[0088] If the laminated pane is to be curved, the outer and inner panes are preferably subjected to a bending process prior to lamination. Preferably, the outer and inner panes are bent congruently together (i.e., simultaneously and using the same tool), as this ensures the shape of the panes is optimally matched for subsequent lamination. Typical temperatures for glass bending processes are, for example, 500°C to 700°C.

[0089] Any opaque cover prints, i.e. in particular black prints around the edge of the pane, are preferably applied using the screen printing process.

[0090] In one embodiment, a masking print can also be provided in the edge region of the composite pane on the inside of the inner pane. This masking print can advantageously also conceal the view from an interior of add-on components, cables or adhesive bonds, thus contributing to a more visually appealing appearance of the composite pane and also improving adhesive bonds or protecting them from UV light. The masking print can be applied directly to the inside of the inner pane. In this case, no HI coating is applied to side IV in this edge region. Alternatively, the masking print can also be formed on the HI coating in the edge region, so that the HI layer essentially covers the entire inside surface of the inner pane. The embodiments described above in connection with the composite pane according to the invention also apply equally to the method according to the invention, and vice versa.

[0091] The invention further comprises the use of a composite pane according to the invention with at least one hologram 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 which serves as a projection surface for a head-up display.

[0092] The invention is explained in more detail 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. They show:

[0093] Fig. 1 is a plan view of an embodiment of a composite pane 100 according to the invention,

[0094] Fig. 2 shows a cross section through the embodiment of a composite pane 100 according to the invention shown in Fig. 1,

[0095] Fig. 3 shows a cross section through a further embodiment of an inventive

[0096] Composite pane 100,

[0097] Fig. 4 shows a cross section through a further embodiment of an inventive

[0098] Composite pane 100,

[0099] Fig. 5 shows a cross section of an embodiment of a hologram element,

[0100] Fig. 6 shows a cross section of another embodiment of a hologram element,

[0101] Fig. 7 shows a cross section of another embodiment of a hologram element, and

[0102] Fig. 8 shows an embodiment of a method according to the invention using a flow chart.

[0103] Fig. 1 shows a plan view of an embodiment of a composite pane 100 according to the invention, and Fig. 2 shows the cross-section through the embodiment of a composite pane 100 according to the invention shown in Fig. 1 along the section line XX'. In the embodiment shown in Fig. 1, the composite pane 100 has an upper edge O, a lower edge U, and two side edges S.

[0104] As shown in Fig. 2, the composite pane 100 comprises an outer pane 1 with an outside surface I and an inside surface II, a first intermediate layer 3, a hologram element 4, an inner pane 2 with an outside surface III and an inside surface IV and an HI coating 6. In the embodiment shown in Figs. 1 and 2, the hologram element 4 is arranged over the entire surface between the outer pane 1 and the inner pane 2, the first intermediate layer 3 is arranged over the entire surface between the outer pane 1 and the hologram element 4 and the HI coating 6 is arranged over the entire surface on the inside surface IV of the inner pane 2.According to the invention, the HI coating 6 is preferably based on silicon nitride, tin-zinc oxide, silicon zirconium nitride, silicon titanium nitride, silicon hafnium nitride, or titanium oxide, particularly preferably based on silicon zirconium nitride or titanium oxide (TiOx). The HI layer 6 is formed, for example, with a layer thickness of 20 nm to 80 nm, particularly preferably of 50 nm to 70 nm.

[0105] The outer pane 1 is made of soda-lime glass, for example, and is 2.1 mm thick. The inner pane 2 is made of soda-lime glass, for example, and is 1.6 mm thick. In the embodiment shown in Figs. 1 and 2, the first intermediate layer 3 is, for example, a thermoplastic intermediate layer, consisting, for example, of polyvinyl butyral (PVB) and is 0.76 mm thick.

[0106] In the embodiment shown in Figs. 1 and 2, the hologram element 4 is designed, for example, as shown in Fig. 5 or 7. If the hologram element 4 is designed as shown in Fig. 7, the hologram element 4 is preferably arranged such that the first substrate layer 8 is arranged directly adjacent to the first intermediate layer 3.

[0107] Fig. 3 shows a cross-section of a further embodiment of a composite pane 100 according to the invention. The composite pane 100 shown in cross-section in Fig. 3 differs from that shown in Fig. 2 only in that the first intermediate layer 3 is arranged between the inner pane 2 and the hologram element 4. In the embodiment shown in Fig. 3, the hologram element 4 is designed, for example, as shown in Fig. 5 or 7. If the hologram element 4 is designed as shown in Fig. 7, the hologram element 4 is preferably arranged such that the first substrate layer 8 is arranged directly adjacent to the first intermediate layer 3.

[0108] Fig. 4 shows a cross-section of a further embodiment of a composite pane 100 according to the invention. The composite pane 100 shown in cross-section in Fig. 4 differs from the one shown in Fig. 2 in that a second intermediate layer 7 is arranged between the hologram element 4 and the inner pane 2. The second intermediate layer 7 is, for example, a thermoplastic intermediate layer and consists, for example, of polyvinyl butyral (PVB) and is 0.76 mm thick.

[0109] In the embodiment shown in Fig. 4, the hologram element 4 is designed, for example, as shown in Fig. 5, 6 or 7.

[0110] Fig. 5 shows a cross section of an embodiment of a hologram element 4. In the embodiment shown in Fig. 5, the hologram element 4 consists of a holographic material 5. The holographic material 5 is, for example, a photopolymer, dichromate gelatin or silver halide gelatin.

[0111] Fig. 6 shows a cross section of another embodiment of a hologram element 4. In the embodiment shown in Fig. 6, the hologram element 4 comprises a first substrate layer 8, a second substrate layer 9 and a holographic material 5 arranged therebetween. The holographic material 5 is, for example, a photopolymer, dichromate gelatin or silver halide gelatin.

[0112] Fig. 7 shows a cross section of a further embodiment of a hologram element 4. In the embodiment shown in Fig. 7, the hologram element 4 comprises a first substrate layer 8 and a holographic material 5. The holographic material 5 is, for example, a photopolymer, dichromate gelatin or silver halide gelatin.

[0113] Fig. 8 shows an embodiment of the method according to the invention for producing a composite pane 100 according to the invention using a flow chart comprising the steps:

[0114] 51 Provision of an outer pane 1 with an outer surface I and an inner surface II, a first intermediate layer 3, a hologram element 4 with at least one hologram and an inner pane 2 with an outer surface III and an inner surface IV and an optically highly refractive layer 6 applied to the inner surface IV.

[0115] 52 Formation of a layer stack in which the first intermediate layer 3 is arranged between the outer pane 1 and the inner pane 2 and the hologram element 4 is arranged between the outer pane 1 and the first intermediate layer 3 or between the inner pane 2 and the first intermediate layer 3.

[0116] 53 Joining the layer stack by lamination.

[0117] According to the invention, precisely one optically highly refractive, preferably transparent, layer is arranged on the interior-side surface of the inner pane (side IV). This optically highly refractive layer, provided according to the invention, advantageously makes it possible to more freely select the angle of inclination of the composite pane in a holographic head-up display projection arrangement, in particular to shift it toward larger Brewster angles. This allows the HUD function to be implemented even with steeper installation positions of the composite pane, as is the case, for example, in trucks or tractors, while simultaneously largely avoiding artifacts and ghost images caused by reflected light. Reference symbols:

[0118] 100 composite panes

[0119] 1 outer pane

[0120] 2 inner pane

[0121] 3 first intermediate layer

[0122] 4 hologram element

[0123] 5 holographic material

[0124] 6 Hl coating (optically highly refractive layer)

[0125] 7 second intermediate layer

[0126] 8 first substrate layer

[0127] 9 second substrate layer

[0128] I outside surface of the outer pane 1

[0129] II Interior surface of the outer pane 1

[0130] III outer surface of the inner pane 2

[0131] IV Interior surface of the inner pane 2

[0132] O top edge

[0133] U bottom edge

[0134] S side edge

[0135] XX' cutting line

Claims

Claims: A laminated glass pane (100), comprising at least an outer pane (1) with an outer surface (I) and an inner surface (II), an inner pane (2) with an outer surface (III) and an inner surface (IV), a first intermediate layer (3), and a hologram element (4) with at least one hologram, wherein the first intermediate layer (3) is arranged between the outer pane (1) and the inner pane (2), the hologram element (4) is arranged between the outer pane (1) and the first intermediate layer (3) or between the inner pane (2) and the first intermediate layer (3), wherein the laminated glass pane (100) is a vehicle window, and wherein an optically high-refractive-index layer (6) with a refractive index greater than or equal to 2 is arranged on the inner surface (IV) of the inner pane (2). A laminated glass pane (100) according to claim 1, wherein the laminated glass pane (100) is a windshield.A composite disc (100) according to claim 1 or 2, wherein the optically high-refractive-index layer (6) is based on silicon nitride, tin-zinc oxide, silicon zirconium nitride, silicon titanium nitride, silicon hafnium nitride, or titanium oxide, preferably based on silicon zirconium nitride or titanium oxide. A composite disc (100) according to any one of claims 1 to 3, wherein the optically high-refractive-index layer (6) has a layer thickness of 10 nm to 100 nm, preferably 20 nm to 80 nm, and particularly preferably 50 nm to 70 nm. A composite disc (100) according to any one of claims 1 to 4, wherein the hologram element (4) comprises a holographic material (5), and the holographic material (5) is configured as a... Coating of the interior surface (II) of the outer pane (1) or as a The outer surface (III) of the inner pane (2) is formed by a coating.

6. Composite disc (100) according to one of claims 1 to 4, wherein the hologram element (4) is arranged between the first intermediate layer (3) and the inner disc (2) and the composite disc (100) additionally comprises a second intermediate layer (7) which is arranged between the inner disc (2) and the hologram element (4).

7. Composite disc (100) according to one of claims 1 to 6, wherein the first intermediate layer (3) and / or, if a second intermediate layer (7) is arranged between the inner disc (2) and the hologram element (4), the second intermediate layer (7) is independently a thermoplastic intermediate layer, an adhesive layer or an optically clear adhesive.

8. Composite disc (100) according to one of claims 1 to 7, wherein the hologram element (4) comprises a holographic material (5) and a first substrate layer (8) and / or a second substrate layer (9).

9. Composite disc (100) according to one of claims 1 to 8, wherein the hologram element (4) comprises a photopolymer, dichromate gelatin or silver halide gelatin, as holographic material (5).

10. Composite disc (100) according to claim 8 or 9, wherein the hologram element (4) comprises a holographic material (5), a first substrate layer (8) and a second substrate layer (9), wherein the first substrate layer (8) is arranged between the holographic material (5) and the first intermediate layer (3) and the second substrate layer (9) is arranged between the holographic material (5) and the second intermediate layer (7).

11. Composite disc (100) according to one of claims 8 to 10, wherein the first substrate layer (8) and / or the second substrate layer (9) comprises polyamide, cellulose triacetate and / or polyethylene terephthalate.

12. Projection arrangement comprising a composite disk (100) according to one of claims 1 to 11 and a projector directed from the side of the inner disk (2) towards the hologram element (4).

13. Method for producing a composite disc (100) according to any one of claims 1 to 11, wherein at least a) an outer disc (1) with an outer surface (I) and an inner surface (II), a first intermediate layer (3), a hologram element (4) with at least one hologram and an inner disc (2) with an outer surface (III) and an inner surface (IV) and a transparent optically high-refractive-index layer (6) applied to the inner surface (IV) are provided, b) a stack of layers is formed in which the first intermediate layer (3) is arranged between the outer disc (1) and the inner disc (2) and the hologram element (4) is arranged between the outer disc (1) and the first intermediate layer (3) or between the inner disc (2) and the first intermediate layer (3), c) the stack of layers is joined by lamination.

14. Method for producing a composite disc (100) according to claim 13, wherein the optically high refractive index layer (6) is applied to the interior surface (III) of the inner disc (2) by wet coating, magnetron sputtering or chemical or physical gas separation processes.

15. Use of a composite screen (100) according to any one of claims 1 to 11 as a vehicle screen in means of transport for traffic on land, in the air or on water, in particular in motor vehicles and in particular as a windscreen which serves as a projection surface for a head-up display.

Images