Composite pane with hologram element

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 a UV protection layer (6) is arranged on the interior-side surface (II) of the outer pane (1). 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

[0002] The invention relates to a composite pane with a hologram element and a UV protective coating, a method for producing such a composite pane, and its use.

[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 chosen. 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] While in head-up displays, in which the projected image is projected toward the viewer via a hologram, reflection of the reference wave on the outer surface of the outer pane is attenuated due to diffraction at the recorded grating of the hologram, reflection of the reference wave on the interior surface of the inner pane can, in particular, 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.

[0014] Holographic materials for holographic HUD applications, for example, for vehicle windshields, can be photosensitive polymers (PP) or gels. Such photosensitive materials are commercially available. It is known that incident light, particularly in the ultraviolet spectrum, can significantly affect the physical properties of such photosensitive materials in holographic films over time. The typical lifespan and durability of windshields is approximately 7 to 12 years, and 2 to 4 years for trucks. The aging effects observed within such periods include changes in color (discoloration), mechanical and physical properties, size, and even the holographic properties of these films.

[0015] WO 2021 / 091818 A1 discloses a laminated glass pane that provides an intermediate layer with UV-absorbing particles to protect the holographic medium from UV light between the outer pane and the holographic medium. A second intermediate layer remains without UV-absorbing particles to enable UV curing of the photosensitive polymer. After curing and lamination to form the laminated glass pane are complete, a UV-absorbing coating is applied to the inner side of the inner pane (side IV). WO 2021 / 219285 A1 describes a vehicle pane comprising an electroluminescent device and an optical band-stop filter, wherein the electroluminescent device emits light, and the optical band-stop filter significantly reduces the radiation of the electroluminescent device in one emission direction. In this way, the emission of light in an undesired emission direction is prevented.The band-stop filter is designed as a thin-film coating comprising optically high-refractive layers with a refractive index greater than 1.8 and optically low-refractive layers with a refractive index of less than 1.8.

[0016] WO 2021 / 041635 A1 discloses a method for producing a glazing unit, wherein a first glass pane, a first intermediate layer, a photopolymer film, a second intermediate layer, and a second glass pane are laminated together, and the photopolymer film is subsequently exposed to light. Optionally, the glazing unit comprises an infrared-reflecting layer, which in turn can optionally also be at least partially reflective within other wavelength ranges, such as the ultraviolet range.

[0017] US 2022 / 0176682 A1 discloses an intermediate layer for laminated panes comprising a hologram element and a first thermoplastic intermediate layer, wherein the first thermoplastic intermediate layer contains a UV absorber.

[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 hologram element in particular can exhibit improved durability and service life. In particular, aging processes such as deterioration of properties, particularly of the holographic properties, or color changes in the visible spectrum should be prevented or at least significantly delayed. Furthermore, the composite pane with the holographic HUD 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 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.

[0022] According to the invention, a UV protection layer is applied to the interior-side surface of the outer pane (side II), at least in the area of ​​the hologram element. "In the area of ​​the hologram element" means that a projection of the hologram element into the plane of the UV protection layer overlaps with the latter. When viewed through the composite pane, the UV protection layer thus lies between the outer pane and the hologram element, so that the UV radiation striking the hologram element through the outer pane first passes through the UV protection layer. The UV protection layer is also referred to as a UV protection coating and is therefore applied in the form of a coating directly to the interior-side surface (side II) of the outer pane.The UV protection layer applied to side II of the outer pane can thus advantageously prevent, or at least largely avoid, aging processes and changes in the material properties of the hologram element caused by external UV radiation in sunlight, or delay them beyond the typical service life of the composite pane. In particular, changes in the photosensitive material caused by incoming sunlight, and in particular the UV light component, and the associated changes and deterioration of the holograms recorded in the holographic material, can be effectively prevented or at least largely avoided. This can advantageously significantly extend the service life of the composite pane while maintaining consistent quality of the holographic HUD function.

[0023] The outer pane, also referred to as the first pane, represents a pane of the laminated pane which, when the laminated pane is installed, is adjacent to the outside environment. The outer pane has an outside surface, also referred to as side I, which points towards and adjoins the vehicle's surroundings. The surface of the outer pane opposite the outside 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 interior when the glazing is installed. The inner pane, also referred to as the second pane, represents the pane of the laminated pane which, when installed in a vehicle, faces the interior. The inner pane has an outside surface, also referred to as side III, which, when installed, faces the outer pane and the environment.The pane 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 interior when installed.

[0024] Preferably, the composite pane is a vehicle pane, i.e. it is suitable for installation in a vehicle, wherein the vehicle pane, in the installed state, separates the vehicle interior from the vehicle surroundings.

[0025] In one embodiment, the UV protective layer is formed from a UV light reflecting and / or UV light absorbing material.

[0026] In a preferred embodiment, the UV protection layer comprises at least one layer of an optically highly refractive material, preferably with a refractive index of greater than or equal to 1.8, particularly preferably greater than or equal to 1.9, in particular greater than or equal to 2.

[0027] In a preferred embodiment, the UV protection layer is preferably an optically highly refractive layer, in particular with a refractive index greater than 1.8, which is formed as a coating, particularly preferably based on silicon nitride, zinc tin oxide, silicon zirconium nitride or titanium oxide (TiOx).

[0028] According to the invention, the optically highly refractive layer can be formed, for example, on the basis of titanium dioxide, silicon nitride, tin-zinc oxide, silicon zirconium nitride, silicon titanium nitride, or silicon hafnium nitride.

[0029] If a layer is formed based on a material, the layer consists predominantly of this material, in particular essentially of this material alongside any impurities or dopants. For example, the UV protection layer can be formed of more than 95 wt.%, preferably more than 97 wt.%, for example 98 wt.% or more (of the UV protection layer) of the mentioned material.

[0030] These high-index layers can preferably be formed with a thickness of 10 nm to 100 nm, particularly preferably with a thickness of 20 nm to 50 nm. In another embodiment, the UV protection layer is multilayered and comprises at least one layer of a high-index material and at least one layer of a low-index material.

[0031] In a further preferred embodiment, it is provided that the multi-layer UV protection layer comprises at least two layers (layers) of a high-refractive material, which are preferably separated from one another by a layer of optically low-refractive material.

[0032] According to the invention, the UV protection coating can be formed from alternating layers with different refractive indices. The multi-layer UV protection coating preferably comprises at least two optically high-refractive-index layers, in particular with a refractive index greater than 1.8, and at least one optically low-refractive-index layer, in particular with a refractive index less than 1.8, for example less than 1.6. Starting from the interior-side surface of the outer pane, a first high-refractive-index layer is arranged, above this a first low-refractive-index layer, and above this a second high-refractive-index layer, preferably over the entire surface. Such an embodiment has proven particularly advantageous with regard to the UV protection effect of the coating.The high-index layers can be based on silicon nitride, zinc tin oxide, silicon zirconium nitride, or titanium oxide, for example, while the low-index layers can be based on silicon dioxide or magnesium fluoride. Both the materials of the optically high-index and the low-index layers (layers) of the UV protection layer can be doped, for example, with other transition metal oxides, such as ZnO, ZrO2, or HfOx.

[0033] 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. Dielectric layers with the refractive indices mentioned and methods for their deposition are known to those skilled in the art in the field of thin films. Preference is given to using methods of physical vapor deposition, in particular magnetron sputtering, or wet coating.The optically low-refractive-index layers, for example made of silicon dioxide or magnesium fluoride, can preferably be formed with a thickness of 10 nm to 100 nm, particularly preferably with a thickness of 20 nm to 50 nm.

[0034] In an exemplary embodiment, the UV protective coating is formed as a three-layer UV protective layer starting from the interior-side surface of the outer pane from a 35 nm thick titanium dioxide layer, a 35 nm thick silicon dioxide layer arranged thereon, and a 30 nm thick titanium dioxide layer arranged thereon.

[0035] In one embodiment, the single- or multi-layer UV protective layer is formed with a layer thickness of 10 nm to 200 nm, preferably from 20 nm to 100 nm, particularly preferably from 30 nm to 80 nm.

[0036] In another embodiment of the composite pane according to the invention, the single- or multi-layer UV protective coating is formed from a UV-absorbing material or comprises such a material. Known examples suitable for the invention are organic layers, for example based on benzotriazole (for example, commercially available under the brand name Tinuvin® from BASF), triazine or benzophenone, or combinations thereof.

[0037] According to the invention, such organic UV protective layers are preferably formed with a thickness between 1 pm and 100 pm, for example with a thickness between 10 pm and 80 pm, for example with 20 pm, 40 pm, 50 pm or 60 pm.

[0038] 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 running between them. For the purposes of the invention, the term "outside surface" refers to the main surface which is 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 which is intended to face the interior in the installed position. The interior-side surface of the outer pane and the outside surface of the inner pane face one another in the composite pane according to the invention.

[0039] The surfaces of the glass panes are typically referred to as follows:

[0040] 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.

[0041] If the composite pane is intended to separate an interior space from the exterior environment in a window opening of a vehicle or building, the inner pane, within the meaning of the invention, refers to the pane facing the interior (vehicle interior). The outer pane refers to the pane facing the exterior environment.

[0042] 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.

[0043] 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.

[0044] The hologram element preferably comprises a photopolymer, dichromate gelatin, or silver halide gelatin as the holographic material, particularly preferably a photopolymer. Silver halides or dichromates are generally used in a gelatin matrix, which is usually first dried at room temperature before a hologram can be recorded by exposure.

[0045] In one embodiment, the holographic material is formed as a coating of the interior surface of the outer pane or as a coating of the exterior surface of the inner pane.

[0046] The composite pane may additionally comprise a second intermediate layer. In this embodiment of the composite pane according to the invention, the hologram element is arranged between the first intermediate layer and the inner pane, and the additional second intermediate layer is arranged between the inner pane and the hologram element.

[0047] 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.

[0048] In a further embodiment, the hologram element comprises a first substrate layer and a holographic material.

[0049] 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.

[0050] The first intermediate layer is preferably a thermoplastic intermediate layer, an adhesive layer or an optically clear adhesive (OCA).

[0051] The second intermediate layer is preferably a thermoplastic intermediate layer, an adhesive layer or an optically clear adhesive (OCA).

[0052] 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.

[0053] 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%.

[0054] The adhesive layer is preferably formed as a homogeneous layer.

[0055] 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.

[0056] The first substrate layer contains, for example, polyamide (PA), cellulose triacetate (TAC), and / or polyethylene terephthalate (PET). The first substrate layer is, for example, 35 pm (micrometers) to 60 pm thick.

[0057] The second substrate layer contains, for example, polyamide (PA), cellulose triacetate (TAC), and / or polyethylene terephthalate (PET). The second substrate layer is, for example, 35 pm (micrometers) to 60 pm thick.

[0058] 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.

[0059] 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.The outer pane and / or the inner pane may have other suitable coatings known per se, for example non-stick coatings, anti-scratch coatings, heatable coatings, sun protection coatings or low-E coatings.

[0060] 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.

[0061] 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.

[0062] A first intermediate layer formed as a thermoplastic intermediate layer can be formed by a single film or by more than one film.

[0063] A second intermediate layer formed as a thermoplastic intermediate layer can also be formed by a single film or by more than one film.

[0064] The first intermediate layer and, if present, the second intermediate layer can independently of one another also be a functional intermediate layer, in particular an intermediate layer with acoustically dampening properties, an infrared radiation-reflecting intermediate layer, an infrared radiation-absorbing intermediate layer, a UV radiation-absorbing intermediate layer, an at least partially colored intermediate layer and / or an at least partially tinted intermediate layer. For example, the first intermediate layer and, if present, the second intermediate layer can independently of one another also be a band filter film. The aforementioned embodiments of the intermediate layers are designed independently of other features of the composite pane. For example, an optional UV radiation-absorbing function of the intermediate layer is provided at most in addition to the UV protection layer of the outer pane, but does not replace it.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 between 350 pm and 800 pm, for example 380 pm or 760 pm.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] A composite pane according to the invention can additionally comprise a cover print, in particular made of a dark, preferably black, enamel. The cover print is in particular a peripheral, i.e. frame-like, cover print. The peripheral cover print primarily serves as UV protection for the assembly adhesive of the composite pane. The cover print can be opaque and cover the entire surface. The cover print can also be semi-transparent, at least in sections, for example as a dot matrix, striped matrix or checkered matrix. Alternatively, the cover print can also have a gradient, for example from an opaque covering to a semi-transparent covering. The hologram element preferably does not extend to the edge of the pane, whereas 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 further layers arranged there and is thus protected from external influences such as moisture and cleaning agents.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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 extend beyond it. The hologram element preferably extends over at least 30%, particularly preferably over at least 50%, and 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.

[0075] 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.

[0076] 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.

[0077] The laminated pane can be, for example, the windshield or roof window of a vehicle or other vehicle glazing, such as a partition in a vehicle, preferably in a rail vehicle or a bus. Alternatively, the laminated pane can be architectural glazing, such as in the exterior facade of a building or a partition inside a building.

[0078] 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 onto the hologram element. The composite pane according to the invention can be designed as described above in the various embodiments. The projector of the projection arrangement emits light at wavelengths to which the hologram, or if more than one hologram is present, the holograms of the hologram element, respond.

[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, wherein a UV protection layer is formed on the inner surface of the outer pane; a first intermediate layer, a hologram element having at least one hologram and an inner pane having an outer surface and an 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 may contain, for example, dichromate gelatin or silver halide gelatin or a photopolymer as holographic material as described above.

[0081] 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.

[0082] The UV protective layer can be applied, 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 outer pane.

[0083] Advantageously, the integration of such a coating in the industrial series production of composite panes can be carried out easily and cost-effectively. 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 with the unexposed hologram element precursor or with the final hologram element with recorded hologram element can also take place. It is understood that a method according to the invention, when the unexposed hologram element precursor is provided in step a), comprises the recording of at least one hologram in the hologram element precursor as an additional step after the lamination of the layer stack.

[0084] 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,

[0085] Calendering processes, vacuum laminators or combinations thereof.

[0086] 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.

[0087] Any opaque cover prints, i.e. in particular black prints around the edge of the pane, are preferably applied using the screen printing process.

[0088] 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. The invention further encompasses the use of a composite pane according to the invention with at least one hologram as interior glazing or exterior glazing in a vehicle or a building, in particular as a vehicle window in means of transport for land, air, or water traffic, in particular in motor vehicles, and in particular as a windshield serving as a projection surface for a head-up display.

[0089] 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:

[0090] Fig. 1 is a plan view of an embodiment of a composite pane 100 according to the invention,

[0091] Fig. 2 shows a cross section through the embodiment of a composite pane 100 according to the invention shown in Fig. 1,

[0092] Fig. 3 shows a cross section through a further embodiment of an inventive

[0093] Composite pane 100,

[0094] Fig. 4 shows a cross section through a further embodiment of an inventive

[0095] Composite pane 100,

[0096] Fig. 5 shows a cross section of an embodiment of a hologram element,

[0097] Fig. 6 shows a cross section of another embodiment of a hologram element,

[0098] Fig. 7 shows a cross section of another embodiment of a hologram element,

[0099] Fig. 8 shows a cross section of an embodiment of a multilayer UV protective layer according to the invention

[0100] Fig. 9 shows an embodiment of a method according to the invention using a flow chart.

[0101] Fig. 1 shows a plan view of an embodiment of a composite pane 100 according to the invention, and Fig. 2 shows a 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. 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 a UV protection layer 6, which is applied, preferably over the entire surface as a coating, to the inside surface II of the outer pane 1. The UV protection layer can thus filter out harmful UV light from the incident sunlight.block and protect the hologram element. Aging processes induced by the UV light component in incident sunlight, and thus changes in the properties and appearance of the composite pane 100 and in particular of the hologram element 4, can be avoided or at least delayed. The durability and service life of the composite pane with the hologram element can thus be significantly increased while maintaining the consistently good quality of the holographic HUD function.

[0102] 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 UV protection coating 6 is applied over the entire surface as a coating on the interior-side surface II of the outer pane 1.

[0103] For example, the outer pane 1 is made of soda-lime glass and is 2.1 mm thick. The inner pane 2 is made of soda-lime glass and is 1.6 mm thick.

[0104] In the embodiment shown in Figs. 1 and 2, the first intermediate layer 3 is, for example, a thermoplastic intermediate layer and consists, for example, of polyvinyl butyral (PVB) and is 0.76 mm thick.

[0105] 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.

[0106] 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.

[0107] 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. 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.

[0111] 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.

[0112] Fig. 8 shows a cross-section of an embodiment of a multilayer UV protection layer 6. In the embodiment shown in Fig. 8, the three-layer UV protection layer comprises a first and a second optically high-refractive-index layer 6a, and an optically low-refractive-index layer 6b arranged between them. The two optically high-refractive-index layers 6a can be formed independently of one another, for example, from silicon nitride, zinc tin oxide, silicon zirconium nitride or titanium oxide, titanium dioxide, while the low-refractive-index layer 6b can be formed, for example, from silicon dioxide or magnesium fluoride. Both the materials of the optically high-refractive-index and the low-refractive-index layers 6a, 6b (layers) of the UV protection layer 6 can be doped, for example, with other transition metal oxides, such as ZnO, ZrO2, HfOx.In an exemplary embodiment, the UV protective coating 6 is formed as a three-layer UV protective layer 6 starting from the interior-side surface of the outer pane II from a 35 nm thick titanium dioxide layer, a 35 nm thick silicon dioxide layer arranged thereon, and a 30 nm thick titanium dioxide layer arranged thereon.

[0113] The layers 6a and 6b of the UV protection layer 6 can preferably be formed with a thickness of 10 nm to 100 nm, particularly preferably with a thickness of 20 nm to 50 nm.

[0114] Fig. 9 shows an embodiment of the method according to the invention for producing a composite pane 100 according to the invention using a flow diagram comprising the steps: 51 Providing an outer pane 1 with an outer surface I and an interior surface II, wherein a single-layer or multi-layer UV protection layer is applied to the interior 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 interior surface IV and an optically highly refractive layer 6 applied to the interior 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] Example

[0118] An outer pane according to the invention is produced with a three-layer UV protection coating on the interior-side surface II of the outer pane, wherein the UV protection coating has the following structure starting from side II: a TiO2 layer with a thickness of 35 nm, a SiO2 layer with a thickness of 35 nm and a TiO2 layer with a thickness of 30 nm.

[0119] An exactly identical outer pane for a laminated pane without the UV protection layer according to the invention is provided in order to carry out comparative measurements of light transmission (TL (A)) and UV light reflection (UV A and UV B blockade).

[0120] These outer panes are measured in a stack with an identical inner pane for a composite pane.

[0121] The results of these measurements are shown in Table 1.

[0122] Table 1

[0123] The measured values ​​obtained and their comparison show that when measuring an outer pane according to the invention, the transmission of visible light is advantageously only very slightly reduced compared to the pane stack without the UV protection layer according to the invention, while both the light components in the UV A and UV B spectrum can be significantly reflected (blocked) by the coating according to the invention on side II of the outer pane. The efficient filtering of the harmful UV light components from the incident sunlight according to the invention can advantageously prevent or significantly delay aging processes, in particular changes in the properties of the hologram element. The durability and service life of a composite pane according to the invention with consistent quality of the holographic HUD function can thus be increased and extended.

[0124] List of reference symbols:

[0125] 100 composite panes

[0126] 1 outer pane

[0127] 2 inner pane

[0128] 3 first intermediate layer

[0129] 4 hologram element

[0130] 5 holographic material

[0131] 6 UV protection layer

[0132] 6a optically highly refractive UV protective layer

[0133] 6b optically low-refractive UV protective layer

[0134] 7 second intermediate layer

[0135] 8 first substrate layer

[0136] 9 second substrate layer

[0137] I outside surface of the outer pane 1

[0138] II Interior surface of the outer pane 1

[0139] III outer surface of the inner pane 2

[0140] IV Interior surface of the inner pane 2

[0141] O top edge

[0142] U bottom edge

[0143] S side edge

[0144] XX' cutting line

Claims

Patent claims 1. Composite 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), and wherein a single- or multi-layer UV protective layer (6) in the form of a coating is applied to the inner surface (II) of the outer pane (2) at least in the area of ​​the hologram element (4).

2. Composite disc (100) according to claim 1, wherein the UV protection layer (6) is formed from a UV light reflecting and / or absorbing material.

3. Composite disc (100) according to claim 1 or 2, wherein the UV protection layer (6) comprises at least one layer of an optically high refractive index material with a refractive index greater than or equal to 1.

8.

4. Composite pane according to one of claims 1 to 3 wherein the UV protective layer (6) comprises at least one optically high refractive index layer (6a) with a refractive index greater than or equal to 1.8, based on titanium dioxide, silicon nitride, tin zinc oxide, silicon zirconium nitride, silicon titanium nitride, or silicon hafnium nitride.

5. Composite disc (100) according to one of claims 1 to 4, wherein the UV protective layer (6) comprises at least one optically low refractive index layer (6b) with a refractive index of less than 1.8, preferably based on silicon dioxide or magnesium fluoride.

6. Composite pane according to one of claims 1 to 5 wherein the UV protective layer (6) comprises at least one layer of an optically high refractive index material (6a) with a refractive index greater than or equal to 1.8 and at least one layer of an optically low refractive index material (6b) with a refractive index less than 1.8, preferably at least two layers of a high refractive index material (6a), wherein the optically high refractive index and optically low refractive index layers (6a, 6b) are preferably arranged alternately over one another.

7. Composite pane according to one of claims 1 to 6 wherein the single- or multi-layered UV- The protective layer (6) is formed with a layer thickness of 10 nm to 200 nm, preferably of 20 nm to 100 nm, particularly preferably of 30 nm to 80 nm.

8. Composite disc (100) according to one of claims 1 to 7, 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).

9. Composite disc (100) according to any one of claims 1 to 8, wherein the first intermediate layer (3) and / or, if present, the second intermediate layer (7) is independently a thermoplastic intermediate layer (3), an adhesive layer or an optically clear adhesive.

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

11. Composite disc (100) according to one of claims 1 to 10, wherein the hologram element (4) preferably comprises a photopolymer, dichromate gelatin or silver halide gelatin, as holographic material (5).

12. Projection arrangement comprising a composite disk (100) according to any one of claims 1 to 11 and a projector directed from an interior space onto the hologram element (4), wherein the interior surface (IV) of the inner disk (2) is the surface of the composite disk (100) closest to the projector. Method for producing a composite disc (100) according to one of claims 1 to 11, wherein at least a) an outer disc (1) with an outer surface (I) and an inner surface (II), wherein a UV protective layer (6) is applied to the 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) 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.Method for manufacturing a laminated glass pane (100) according to claim 13, wherein the one or more layers of UV protection (6) are applied to the inner surface (II) of the outer glass pane (1) by wet coating, magnetron sputtering, or chemical (CVD) or physical vapor deposition (PVD) processes. Use of a laminated glass pane (100) according to any one of claims 1 to 11 as. Interior or exterior glazing in a vehicle or building, in particular as a vehicle window 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.

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