Illuminated glazing element with a coated reflective structure for coupling in light

Abstract

The invention relates to an illuminated glazing element, comprising a transparent layer (2, 7) with a first surface (III, i) and a second surface (IV, ii) and comprising a light source (5) for generating light, said light source being arranged such that the light is irradiated into the transparent layer (2, 7) via the second surface (IV, ii), wherein a reflective structure with a reflective surface (8, 11) is formed in the first surface (III, i) or is secured to the first surface (III, i), and the reflective surface (8, 11) has a plurality of sections which are inclined towards the second surface (IV, ii) and is configured such that the light irradiated into the transparent layer (2, 7) is reflected on the reflective surface (8, 11) and is at least partly coupled back into the transparent layer (2, 7) at a coupling-in angle which is suitable for diffusing the coupled light in the transparent layer (2, 7), in particular by means of a total reflection on the first surface (IIII, i) and the second surface (IV, ii). The reflective surface (8, 11) is provided with a reflective coating (20) which comprises, in the following order starting from the reflective surface (8, 11): - a primer layer (21) and - a reflective layer (22) based on a metal or a metal alloy.

Description

[0001] Illuminated glazing element with a coated reflective structure for light coupling

[0002] The invention relates to an illuminated glazing element and its use.

[0003] Illuminated glazing elements are known as such. For illumination, a light source, typically a light-emitting diode, can be arranged on the side edge surface or in a recess of a glass pane of the glazing element, so that light is coupled into the glass pane via the side edge surface or the edge surface of the recess and spreads there as a result of total internal reflection. The light is often coupled out of the glass pane again by light-scattering structures, thereby creating the illumination. The shape of the light-scattering structures can be freely selected, so that illuminated surfaces of any shape, for example, as a pattern, can be created. Illuminated glazing elements of this type are known, for example, from WG2014 / 060409A1 or WO2014 / 167291 A1.

[0004] In the automotive sector, such illuminated glazing elements are particularly interesting as roof panels, through which the interior can be illuminated. The illuminated glass pane typically represents the inner pane of a laminated pane. However, such illuminated glazing elements can also be used for other vehicle windows, as well as for windows in buildings and architecture, or in furnishings. Instead of illuminating an interior, the illuminated surfaces formed by the light-diffusing structures can also be used to display information, for example, directional arrows, status indicators, warnings, price lists, or similar.

[0005] In the subsequently published international application WO2023144282A1, it was proposed that light be coupled into the light-guiding layer (for example, a glass pane or light guide plate) of the glazing element not via the side edge surface, but rather via a main surface of the light-guiding layer. For this purpose, a reflective structure with a reflective surface is attached to or formed in the first surface of the light-guiding layer. The reflective surface has sections inclined relative to one another. The reflective structure is irradiated by a light source through the light-guiding layer, wherein the light is reflected at the inclined sections of the reflective surface in such a way that it propagates in the light-guiding layer as a result of total internal reflection. The reflective surface is provided with a reflective coating made of silver or aluminum for this purpose.The reflective structure can, for example, be formed as a microprism film which is attached to the first surface of the light-conducting layer.

[0006] It has been shown that microprism film coated with a reflective layer made of silver or aluminum can experience delamination. During aging tests, such as temperature cycling, the microprism film sometimes detaches from the microprism film. This could be due to a difference in the thermal expansion coefficient between the reflective layer and the microprism film, or to outgassing from the microprism film.

[0007] The present invention is based on the object of providing an improved illuminated glazing unit in which the light from a light source irradiates a reflective structure through a transparent layer and is coupled into the transparent layer by reflection from a reflective surface of the reflective structure. For this purpose, the reflective surface should be provided with a reflective coating that adheres securely and, in particular, does not detach from the reflective surface, even under thermal stress.

[0008] The object of the present invention is achieved by an illuminated glazing element according to claim 1. Preferred embodiments emerge from the subclaims.

[0009] The illuminated glazing element, within the meaning of the invention, is a pane- or plate-like object comprising at least one glass pane and, in particular, structurally formed from at least one glass pane. The glazing element can be a single glass pane and structurally consist only of said glass pane. The glazing element can alternatively be a laminated pane or insulating glazing containing said glass pane. In a laminated pane, the glass pane is connected to another pane via a thermoplastic intermediate layer. In an insulating glazing unit, the glass pane is connected to another pane via a circumferential spacer in the edge region, thereby forming a space between the panes that is typically filled with an inert gas or evacuated. The glazing element can be used as a window pane, for example as a window pane in vehicles, buildings, or interiors.The glazing element can also be used as a component of furniture or electrical appliances, for example, as a door panel for a cupboard or shelf, or as a panel for an oven door. The glazing element can also be used as a furnishing item, for example, as a display panel in bars or nightclubs.

[0010] The illuminated glazing element according to the invention comprises or contains at least one transparent layer and a light source designed and suitable for generating light. The transparent layer has a first surface (main surface), a second surface (main surface), and a side edge surface extending therebetween. The light source is arranged such that the light is radiated (at least partially) into the transparent layer via the second surface. The light passes through the transparent layer and strikes the first surface.

[0011] A reflective structure having a reflective surface is formed in the first surface or attached to the first surface. The reflective surface has a plurality of sections inclined relative to the second surface and is configured such that the light irradiated into the transparent layer and passed through the transparent layer is reflected by the reflective surface and at least partially recoupled into the transparent layer. The light is reflected by the reflective surface into the transparent layer and coupled into it at a coupling angle suitable for the coupled-in light to propagate at least partially (at least a portion of the coupled-in light) in the transparent layer, in particular by total internal reflection at the first surface and the second surface of the transparent layer.

[0012] More precisely

[0013] - the light passes through the transparent layer, strikes the first surface and is reflected there, if the reflective structure is formed in the first surface; the reflective surface of the reflective structure is then a partial area of ​​the first surface and the light is reflected by this partial area;

[0014] - the light passes through the transparent layer, exits the transparent layer again via the first surface, and is reflected on the reflective surface of the reflective structure if the reflective structure is attached to the first surface; preferably, the light exiting the transparent layer passes through the reflective structure and is reflected on its surface facing away from the transparent layer, which surface forms the reflective surface.

[0015] The reflective surface is provided with a reflective coating. According to the invention, the reflective coating comprises at least a primer layer and a reflective layer based on a metal or metal alloy, which are arranged in the specified order starting from the reflective surface. The primer layer is thus arranged below the reflective layer, and the reflective layer is arranged above the primer layer. In other words, the primer layer is arranged between the reflective layer and the reflective surface.

[0016] The primer layer according to the invention particularly improves the adhesion of the reflective coating to the reflective surface. This prevents delamination effects, and the reflective coating adheres stably to the reflective surface even after aging tests. The primer layer also acts as a barrier between the reflective structure and the metal-containing reflective layer. This prevents, for example, the diffusion of chemical components or oxygen from the reflective structure into the reflective layer, effectively reducing aging and corrosion of the reflective layer. These are major advantages of the present invention.

[0017] The different layers of the reflective coating are preferably thin films. For the purposes of the invention, this refers to layers with a thickness of less than 1 pm. The thin films are deposited, in particular, by means of vapor deposition.

[0018] If a first layer is deposited above a second layer, this means, within the meaning of the invention, that it has a greater distance from the reflective surface than the second layer. If a first layer is deposited below a second layer, it has a shorter distance from the reflective surface than the second layer.

[0019] If a layer of the reflective coating is formed based on a material, this means, within the meaning of the invention, that the layer consists predominantly of the material, i.e., in a proportion of at least 50 wt.%, preferably at least 70 wt.%, particularly preferably at least 90 wt.%. The layer may also contain, in particular, dopants and / or impurities, preferably in a proportion of up to 10 wt.%.

[0020] The reflective layer of the reflective coating is preferably based on silver or aluminum. This achieves particularly good reflective properties. The proportion of said metal in the reflective layer is preferably at least 90%, more preferably at least 95%, and most preferably at least 99%. In addition, the reflective layer may contain dopants or impurities.

[0021] The reflective layer preferably has a thickness of 50 nm to 250 nm. This achieves particularly good reflective properties.

[0022] If the reflective layer is based on silver, its thickness is preferably from 50 nm to 150 nm, particularly preferably from 80 nm to 120 nm, for example approximately 100 nm. If the reflective layer is based on aluminum, its thickness is preferably from 150 nm to 250 nm, particularly preferably from 180 nm to 220 nm, for example approximately 200 nm. This is advantageous with regard to the reflective properties without having to use too much material. For the purposes of the present invention, the thickness always means the geometric layer thickness, not the optical layer thickness, which results from the product of the geometric thickness and the refractive index.

[0023] The primer layer of the reflective coating is preferred

[0024] - based on a nickel alloy, particularly preferably nickel-chromium (NiCr) or nickel-vanadium (NiV),

[0025] - based on silicon oxide (SiCh), silicon nitride (SisN^ or silicon oxynitride (SiO x N y ),

[0026] - based on chromium (Cr) or a chromium alloy,

[0027] - based on tin (Sn) or a tin alloy,

[0028] - based on a titanium alloy or an oxide or nitride of a titanium alloy,

[0029] - based on zinc (Zn) or a zinc alloy, particularly preferably zinc-aluminium (ZnAl), or

[0030] - based on copper (Cu) or a copper alloy. With these materials, good results are achieved with regard to the adhesion of the reflective coating and the barrier effect of the primer layer. The primer layer preferably has a thickness of 0.5 nm to 10 nm. If the primer layer is based on a metal or a metal alloy, in particular selected from the aforementioned metals and metal alloys, its thickness is particularly preferably from 0.5 nm to 5 nm, very particularly preferably from 1 nm to 3 nm. If the primer layer is based on an oxide, nitride or oxynitride, in particular selected from the aforementioned oxides, nitrides and oxynitrides, its thickness is particularly preferably from 5 nm to 10 nm.

[0031] It is particularly advantageous if the primer layer is based on a metal or a metal alloy and is comparatively thin, with a thickness of 0.5 nm to 5 nm, in particular 1 nm to 3 nm. Then, the propagation direction of the light from the light source is influenced very little. Particularly preferred metals and metal alloys are those mentioned above, i.e.

[0032] - Nickel alloys, especially nickel-chromium (NiCr) or nickel-vanadium (NiV),

[0033] - Chromium (Cr) or a chromium alloy,

[0034] - Tin (Sn) or a tin alloy,

[0035] - titanium alloys,

[0036] - zinc (Zn) or a zinc alloy, in particular zinc-aluminium (ZnAl), or

[0037] - Copper (Cu) or a copper alloy.

[0038] The primer layer is preferably in direct contact with the reflective surface of the reflective structure, particularly preferably also with the reflective layer.

[0039] In an advantageous embodiment, the reflective coating comprises a corrosion protection layer arranged above the reflective layer. The reflective layer is thus arranged between the primer layer and the corrosion protection layer. The corrosion protection layer protects the underlying layers, in particular the reflective layer, from corrosion. This is particularly advantageous if the reflective structure is not embedded hermetically in the glazing element immediately after application of the reflective coating, but is first stored or exposed to air for an extended period during the manufacture of the glazing element. In such a case, the metal-based reflective layer could corrode, in particular oxidize due to atmospheric oxygen, which is prevented or at least significantly delayed by the corrosion protection layer.

[0040] The corrosion protection layer is preferred

[0041] - based on a nickel alloy, particularly preferably nickel-chromium (NiCr) or nickel-vanadium (NiV),

[0042] - based on silicon oxide (SiCh), silicon nitride (SisN^ or silicon oxynitride (SiO x N y ),

[0043] - based on chromium (Cr) or a chromium alloy,

[0044] - based on tin (Sn) or a tin alloy,

[0045] - based on a titanium alloy or an oxide or nitride of a titanium alloy,

[0046] - based on zinc (Zn) or a zinc alloy, particularly preferably zinc-aluminium (ZnAl), or

[0047] - Based on copper (Cu) or a copper alloy. This achieves good results.

[0048] The corrosion protection layer preferably has a thickness of 10 nm to 50 nm, particularly preferably 30 nm to 40 nm. With these thicknesses, good corrosion protection is achieved without having to use too much material.

[0049] A passivating oxide layer can form on the surface of the corrosion protection layer (exposed away from the reflective layer), particularly if the corrosion protection layer is based on a metal or a metal alloy.

[0050] The reflective layer can, in principle, comprise additional layers. In a preferred embodiment, however, the reflective layer is in direct contact with the primer layer (and the corrosion protection layer, if present). A further layer can be provided above the electrically conductive layer (if no corrosion protection layer is present) or above the corrosion protection layer (if such a layer is present), which, for example, improves the connection to adjacent components of the glazing element or serves as a barrier.

[0051] It is particularly preferred that the reflective layer consists only of the layers mentioned here (primer layer, electrically conductive layer, optionally corrosion protection layer) and has no further layers. The reflective layer therefore particularly preferably consists exclusively of the primer layer and the reflective layer, or of the primer layer, the reflective layer, and the corrosion protection layer.

[0052] The transparent layer of the glazing element can also be referred to as a transparent layer, a light-conducting layer, or a light-conducting layer. It is, in particular, a transparent glass or polymer layer. The transparent layer is preferably a rigid layer. It can be designed, for example, as a glass pane or plate or as a plastic pane or plate. The glass pane or plastic pane can form an outer pane of the glazing element exposed to the environment, or it can be embedded in the glazing element as a light guide plate. A flexible light guide film can also be embedded in the glazing element and function as a transparent layer, for example a PET film with a thickness of 30 μm to 200 μm. The transparent layer has the task of distributing the light radiated by the light source across the surface of the glazing element in the manner of a light guide.

[0053] The transparency of the transparent layer, which gives it its name, refers in particular to the wavelength or wavelength range of the light source. The transparent layer preferably has a light transmission of at least 70%, particularly preferably at least 80%, and most preferably at least 90%, relative to the light from the light source.

[0054] The first surface of the transparent layer faces away from the light source, while the second surface of the transparent layer faces the light source. The light source irradiates the transparent layer, with the light entering the transparent layer via the second surface, passing through the transparent layer, and striking the first surface of the transparent layer.

[0055] The second surface is, in particular, smooth (flat or curved). The first surface is preferably also smooth and arranged parallel to the second surface—with the exception of the area of ​​the reflective surface if the reflective structure is formed directly in the first surface.

[0056] The reflective structure serves to couple light into the transparent layer. It is arranged opposite the light source on the first surface of the transparent layer, in particular, attached to the first surface of the transparent layer, or formed in the first surface, so that the light passing through the transparent layer strikes the reflective structure and is (at least partially) reflected back toward the transparent layer by its reflective surface, which is provided with the reflective coating.

[0057] Typically, not the entire first surface of the transparent layer is provided with the reflective structure, but only a partial area of ​​the first surface that is irradiated by the light source.

[0058] The reflective structure can comprise a separate component of the glazing unit or be formed from it, in particular a microprism film. The component is attached, for example, glued, to the first surface. The reflective surface of the reflective structure faces away from the transparent layer. The component is transparent. The light from the light source exits the transparent layer again via the first surface, passes through the component, and strikes its reflective surface, where it is reflected and passes through the component again, re-entering the transparent layer via the first surface.

[0059] A microprism film is a flexible, particularly foil-like, polymeric film that has a smooth surface facing the transparent layer and, in particular, is arranged on it, and a structured surface facing away from the transparent layer. The structured surface is in the form of a planar arrangement of a plurality of prisms with dimensions in the micrometer range, wherein the prism surfaces form the inclined sections of the reflective surface. The microprisms (provided with the reflective coating) act in particular as reflection prisms and reflect the light striking them in a direction that depends on the angle of inclination of the prism surfaces and the angle of incidence of the light. Microprism films are commercially available and can be purchased or specially produced during the manufacture of the glazing element according to the invention.The edge length of the individual microprisms is preferably from 10 pm to 250 pm, particularly preferably from 20 pm to 100 pm, for example about 30 pm.

[0060] The microprism film can be multilayered. Commonly used microprism films include a substrate layer, for example, based on polyethylene terephthalate (PET), on which the microprisms are formed from a UV-curing polyacrylate.

[0061] The microprism film is transparent and preferably has a light transmission of at least 70°, particularly preferably at least 80°, and most preferably at least 90°, relative to the light from the light source. It is advantageous if the difference between the refractive indices of the transparent layer and the microprism film is as small as possible in order to minimize reflection losses at the interface between the transparent layer and the microprism film. Preferably, said difference in the refractive indices is at most 0.02 (relative to a wavelength of 550 nm), particularly preferably at most 0.01. If the transparent layer and the microprism film differ in refractive index, the microprism film preferably has a higher refractive index than the transparent layer, which is advantageous for high-yield light coupling.

[0062] Instead of a flexible microprism film, a rigid microprism plate can also be used, i.e. a rigid plastic plate with a flat arrangement of microprisms.

[0063] The reflective structure can also be formed directly in the first surface of the transparent layer. For this purpose, a portion of the first surface is formed as a reflective surface. This is particularly easy to implement when the transparent layer is a polymer layer, for example, a plastic disc or plate. The light is reflected directly by the first surface and thrown back into the transparent layer without escaping from the transparent layer. If the reflective surface with the reflective coating is only partially reflective, then a portion of the light naturally escapes from the transparent layer via the first surface and is not reflected.

[0064] According to the invention, the reflective surface of the reflective structure has sections that are inclined relative to the second surface of the transparent layer. This means that the sections are not arranged parallel to the second surface, but at an angle greater than 0° to the second surface. Said sections are arranged at an angle to the second surface of between 0° and 90°, preferably from 28° to 60° or from 30° to 60°, very particularly preferably from 30° to 50°, in particular from 40° to 50°, for example approximately 45°. This refers to the absolute value of the respective angle. The sections can be inclined in different directions.

[0065] The sections are preferably also inclined relative to each other. This means that adjacent sections are inclined relative to each other, i.e., they are not arranged parallel, but at an angle between 0° and 180° to each other.

[0066] Said sections of the reflective surface are preferably substantially flat. The inclination of the sections of the reflective surface relative to the second surface of the transparent layer determines the angle at which the reflected light is reflected back into the transparent layer.

[0067] The first and second surfaces of the transparent layer represent interfaces to the adjacent medium, either the surrounding atmosphere or another layer or position of the glazing element. Typically, the adjacent medium has a different refractive index than the transparent layer. If the adjacent medium has a lower refractive index than the transparent layer, this results in a critical angle of total internal reflection, which is determined as a T = arcsinf— ), where ni is the refractive index of the transparent layer and n2 is the refractive index of the adjacent medium.

[0068] The sections of the reflective surface are in particular inclined such that at least a portion of the light is reflected back into the transparent layer at an input angle such that it hits the second surface at an angle (angle of incidence) that is greater than the critical angle of total internal reflection. The light beam is totally reflected at the second surface at an angle of reflection that corresponds to the angle of incidence. The light hits the first surface at precisely this angle of incidence, where it is again totally reflected. The light does not escape into the environment and, as a result of repeated total internal reflection, propagates essentially losslessly in the transparent layer, being reflected back and forth between the two surfaces of the transparent layer.As is common in ray optics, the angle of incidence is the angle that the light ray impinging on the surface makes with respect to the surface normal at the point of impact. The angle of reflection is determined analogously to the surface normal, as is the critical angle of total internal reflection.

[0069] In certain embodiments of the invention, the medium adjacent to the first surface of the transparent layer differs from the medium adjacent to the second surface. This is the case, for example, with composite panes consisting of two laminated glass panes, one of the glass panes being used as the transparent layer. In this case, one of the surfaces of said glass pane borders the surrounding atmosphere and the other surface borders the thermoplastic intermediate layer of the composite pane. Therefore, different critical angles of total reflection occur at the two surfaces. In this case, the reflective surface is designed such that at least part of the light is reflected back into the transparent layer at such an input angle that it hits the second surface at an angle (angle of incidence) that is greater than the greater critical angle of total reflection.These light components spread through the transparent layer as a result of repeated total reflection on both surfaces.

[0070] The light propagates in the transparent layer until it either hits the side edge surface of the transparent layer and is coupled out there or hits a light-scattering structure on one of the two surfaces of the transparent layer, which interrupts the total reflection by light scattering, whereby the light is coupled out of the transparent layer via the surface in question.

[0071] The glazing element is provided with a light source suitable for coupling light into the glass pane. During operation, the light source emits visible light, i.e. electromagnetic radiation in the visible spectral range, in particular in the range from 380 nm to 780 nm. The light source can have one or more emission bands which are arranged in the visible spectral range and cover or cover part of it. However, the light source can also have a broad emission band which covers the entire visible spectral range. The emission band(s) - and thus the color of the emitted light - can be freely selected according to the requirements of the specific application. The glazing element can have a single light source or several separate light sources whose light is coupled into the transparent layer at different points.

[0072] The light source preferably comprises at least one light-emitting diode (LED). The light source can be a single light-emitting diode, but is preferably an array of multiple light-emitting diodes. Said array is preferably installed in a common housing, for example, as a linear array in which the light-emitting diodes are arranged along a line. The electroluminescent material of the light-emitting diode can be, for example, an inorganic semiconductor or an organic semiconductor. In the latter case, it is also referred to as an organic light-emitting diode (OLED).

[0073] The light from the light source can be radiated into the glazing unit directly or via an optical element, for example a lens. In an advantageous embodiment, the light from the light source is radiated into the glazing element or into the transparent layer via a collimator. The collimator generates from the typically divergent light beam from the light source a light beam with a preferably essentially parallel beam path, or at least a less divergent, i.e. more concentrated beam path. This has the advantage that the entire light beam is radiated into the glazing element at the same angle of incidence, in particular at an angle of incidence which, in conjunction with the inclination of the sections of the reflective surface of the reflective structure, ensures that as large a proportion of the light as possible is coupled into the transparent layer in such a way that total internal reflection occurs at the surfaces.This optimizes the light output.

[0074] In the simplest case, the collimator is a type of converging lens with the light source positioned at its focal point. The collimator can be made of glass or a transparent plastic, particularly polycarbonate (PC) or polymethyl methacrylate (PMMA). If the light source is an array of multiple light-emitting diodes, a separate collimator can be provided for each light-emitting diode. However, a common collimator is preferably used for the entire LED array. In the case of a linear LED array, a rod-like collimator can be used, for example, whose length is at least equal to the length of the LED array. If the glazing element is a composite pane, the collimator is preferably attached, for example by adhesive, to the exposed (interior-facing) surface of the inner pane.The light source is attached to the surface of the collimator facing away from the laminated pane, for example, glued, screwed, or snapped into the collimator. If the glazing element is a monolithic pane, in particular a single pane of glass, the collimator is preferably attached to the second surface, for example, glued.

[0075] The collimated light beam is preferably irradiated into the glazing element at an angle of incidence other than 0°. The angle of incidence is determined as the angle to the surface normal on the exposed surface of the glazing element facing the light source, for example, the interior-side surface of the inner pane of a laminated pane. The angle of incidence is selected such that the largest possible proportion of the light (preferably essentially all of the light) is coupled into the transparent layer in such a way that total reflection occurs at the surfaces of the transparent layer and the light thus propagates within the transparent layer. The suitable angle of incidence lies within an angular range that depends significantly on the refractive indices of the media adjacent to the transparent layer (similar to the numerical aperture of a light guide).The appropriate angle of incidence also depends on the orientation of the inclined sections of the reflective surface relative to the light source and (in the case of a separate component with the reflective surface, especially a microprism film) also on the refractive index of the material of said component. The orientation (inclination) of the sections of the reflective surface of the reflective structure determines the direction of the reflected light (angle of incidence corresponds to angle of reflection). The appropriate angle of incidence can be selected by a person skilled in the art for the specific application using simple optical calculations.

[0076] An angle of incidence other than 0° is achieved, for example, by the surface of the collimator facing the transparent layer not being parallel to the surface facing the light source to which the light source is attached.

[0077] In a preferred embodiment, the transparent layer according to the invention is provided with at least one light-scattering structure suitable for coupling the light out of the transparent layer via its first surface and / or via its second surface. The light-scattering structure is arranged on the first or second surface or is in contact with one of these surfaces. If the light propagating in the transparent layer strikes the light-scattering structure, it is scattered, preventing total internal reflection and causing the scattered light to be coupled out and leave the transparent layer.

[0078] The light-diffusing structure appears as a luminous surface of the glazing element. This can be used, for example, to illuminate an interior or to display symbols or patterns that serve to convey information or may be intended for purely aesthetic reasons. The light-diffusing structure can be present in a single, contiguous area of ​​the glass pane or in several separate areas. The light-diffusing structure allows for the creation of any shape or pattern.

[0079] The light-scattering structure can be applied directly to or formed on the first or second surface of the transparent layer. Alternatively, the light-scattering structure can be provided, for example, on a carrier film that is attached to the first or second surface, for example by gluing. If the glazing element according to the invention is a laminated pane, the light-scattering structure can be applied to the surface of a thermoplastic intermediate layer that is in contact with the transparent layer. Alternatively, the light-scattering structure (for example, applied to a carrier film) can be inserted between the transparent layer and the intermediate layer.

[0080] In an advantageous embodiment, the light-scattering structure is formed as a print, in particular as a print on one of the surfaces of the transparent layer or - in the case of a laminated pane - on the surface of the adjacent intermediate layer facing the transparent layer. If the transparent layer is made of glass (for example, the inner pane of a laminated pane or an embedded light guide plate made of glass), a print on it is preferably formed as a light-scattering enamel. This enamel can be applied, for example, using a screen printing process. It preferably contains glass frits, which are fired into the surface of the glass layer, creating a roughened and therefore light-scattering surface.An imprint on a polymer layer (for example, an intermediate layer or a polymer light guide plate) can be realized by printing a surface of the polymer layer with a light-scattering printing paste, for example, using a screen printing process. In an advantageous embodiment, the light-scattering structure is transparent, so that it does not significantly restrict visibility through the glazing element. The imprint (the enamel or printing paste) therefore preferably contains no pigment. However, opaque or semi-transparent light-scattering structures with pigments are also conceivable, for example, white structures.

[0081] Light-scattering structures can also be created by roughening the relevant surface of the transparent layer. This roughening can be achieved mechanically (e.g., by grinding techniques) or by laser processing. Laser processing, particularly in the case of a laminated pane, has the advantage that the light-scattering structure can also be incorporated into the finished laminated pane, even if it is intended to be located inside the laminated pane, since the laser radiation can also be focused onto a plane inside the laminated pane. Laser processing also makes it possible to create the light-scattering structure not on a surface, but inside the transparent layer.

[0082] However, the light-scattering structure is not absolutely necessary within the scope of the present invention. Applications are also conceivable in which the light is to be coupled out via the side edge surface of the transparent layer, whereby no light-scattering structures are required on the first or second surface.

[0083] The glazing element can be a monolithic pane, in particular a single pane of glass. Structurally, the glazing element is formed exclusively by a single pane of glass, which also functions as a transparent layer within the meaning of the invention. The pane of glass has, for example, a thickness of 1 mm to 10 mm and is preferably made of soda-lime glass. The pane is preferably made of clear glass without tints or colors. The single pane of glass is typically intended as a window pane for separating an interior space from an external environment. It has an interior-side surface which, in the installed position, faces the interior space and an exterior surface which, in the installed position, faces the external environment. The interior-side surface is preferably the second surface within the meaning of the invention, and the light source is attached to it.The outer surface is the first surface within the meaning of the invention and is provided with the reflective structure. Instead of a single glass pane, a single polymer pane made of a clear, transparent plastic can in principle also be used. In an advantageous embodiment, however, the glazing element according to the invention is designed as a composite pane. The composite pane comprises an outer pane and an inner pane, which are connected to one another via at least one thermoplastic intermediate layer. The outer pane and the inner pane each have an interior-side surface which, in the installed position, faces the interior, and an outer surface which, in the installed position, faces the outside environment. The outer and interior surfaces are typically intended for viewing, with a side edge surface extending between them.The interior-side surface of the outer pane and the exterior-side surface of the inner pane face one another and are connected to one another by the at least one intermediate layer. The outer pane and the inner pane are preferably made of glass, in particular soda-lime glass, and each have a thickness of, for example, 0.5 mm to 10 mm, preferably 1 mm to 5 mm. The intermediate layer (or each intermediate layer, if several are present) is preferably made of a thermoplastic film, for example based on polyvinyl butyral (PVB), ethylene-vinyl acetate (EVA) or polyurethane (PU), and has a thickness of, for example, 0.3 mm to 1.0 mm. Instead of glass panes, polymer panes made of a clear, transparent plastic can in principle also be used as the outer pane and / or inner pane. The light source is preferably attached to the interior-side surface of the inner pane.

[0084] If a polymeric film or layer is based on a material, this means, within the meaning of the invention, that the film or layer consists predominantly of the material, i.e., the proportion of the material is more than 50% by weight, preferably more than 60% by weight. Furthermore, the film or layer can contain other components, for example, plasticizers, stabilizers, UV or IR blockers.

[0085] The inner pane is preferably made of clear glass to ensure efficient light penetration. The outer pane and the intermediate layers between the transparent layer and the outer pane can be tinted or colored.

[0086] In a first preferred variant of the composite pane, the outer pane or the inner pane is the transparent layer within the meaning of the invention, particularly preferably the inner pane. The interior-side surface of the inner pane (or outer pane) is in particular the second surface within the meaning of the invention, and the exterior surface is the first surface provided with the reflective structure. The reflective structure preferably comprises a separate component or is formed therefrom, in particular a microprism film. The component is preferably attached to the exterior surface of the inner pane (or outer pane). The component can be adhesively bonded to the surface or (in the case of the inner pane) fixed there by the contact pressure of the at least one intermediate layer.

[0087] In a second preferred variant, the composite pane has a light guide plate arranged between two intermediate layers. The at least two intermediate layers and the light guide plate are arranged between the outer pane and the inner pane. The light guide plate is the transparent layer within the meaning of the invention, wherein the first surface within the meaning of the invention is preferably the outer surface of the light guide plate and the second surface is the inner surface. In one embodiment, the light guide plate is a glass pane, in particular a comparatively thin glass pane with a thickness of 0.2 mm to 3 mm, preferably 0.5 mm to 2.1 mm, for example 0.5 mm to 1 mm.In a further embodiment, the light guide plate can be a polymer light guide plate, preferably made of a clear, rigid plastic such as polycarbonate (PC) or polymethyl methacrylate (PMMA), for example with a thickness in the ranges specified above for the glass light guide plate.

[0088] Instead of the light guide plate, the composite pane can also have a flexible light guide film (light guide foil) as a transparent layer.

[0089] The reflective structure can comprise or be formed from a separate component, in particular a microprism film. The component is attached to the first surface of the light guide plate, in particular the outer surface. The component can be glued to the light guide plate or fixed there by the contact pressure of the adjacent intermediate layer.

[0090] The reflective structure can alternatively be formed directly in the first surface of the light guide plate (in its function as a transparent layer). This is comparatively easy to implement, especially when the light guide plate is made of plastic. The reflective surface with the inclined surfaces can be created, for example, by removing material from a region of the first surface, for example, by milling or grinding, by laser processing, or by chemical processing such as etching. The reflective surface can alternatively be formed by additionally applying polymeric material to the first surface, for example, made of UV-curing polyacrylate.

[0091] The composite pane preferably has an opaque masking region through which no vision is possible. This masking region is preferably arranged circumferentially in an edge region of the composite pane and surrounds a central transparent see-through region in a frame-like manner. This is particularly common for vehicle windows. The masking region is formed in particular by an opaque element which is arranged outside the reflective structure, preferably between the reflective structure and the outer pane. The masking region can be formed by an opaque cover print, which is particularly preferably applied to the interior-side surface of the outer pane. Alternatively, a tinted intermediate layer (or a tinted section of an intermediate layer) can form said opaque element.

[0092] The glazing element can be flat or curved in one or more directions of the room.

[0093] The reflective coating is preferably deposited on the reflective surface by vapor deposition, for example, by chemical vapor deposition (CVD), plasma-enhanced chemical vapor deposition (PECVD), or atomic layer deposition (ALD). Physical vapor deposition (PVD), for example, vapor deposition, is particularly preferred, and cathodic sputtering and, in particular, magnetic field-assisted cathodic sputtering are particularly preferred.

[0094] If the glazing element is designed as a composite pane, known lamination processes can be used for its production, for example autoclave processes, vacuum bag processes, vacuum ring processes, calender processes, vacuum laminators or combinations thereof. The connection of the outer pane and inner pane usually takes place under the influence of heat, vacuum and / or pressure. The invention also encompasses the use of a glazing element according to the invention as a window pane of a vehicle. A particularly preferred use is a vehicle roof pane, which is used to illuminate the vehicle interior. The vehicle can in principle be any land vehicle, watercraft or aircraft, and is preferably a passenger car, truck or rail vehicle.The glazing element can also be used in buildings, for example as a window pane, glass facade, or glass door, either indoors or outdoors, in particular as a window pane of a building or an interior. The glazing element can also be used as a component of furniture, electrical appliances, as a component of furnishings, or as a furnishing item.

[0095] The invention is explained in more detail below with reference to a drawing and exemplary embodiments. The drawing is a schematic representation and not to scale. The drawing does not limit the invention in any way.

[0096] They show:

[0097] Fig. 1 shows a cross section through an embodiment of the inventive

[0098] glazing element,

[0099] Fig. 2 shows an enlarged section Z from Figure 1,

[0100] Fig. 3 shows a further enlarged section Y from Figure 2,

[0101] Fig. 4 shows a cross section through a further embodiment of the inventive

[0102] glazing element,

[0103] Fig. 5 shows an enlarged section X from Figure 4.

[0104] Figures 1, 2, and 3 each show a detail of a first embodiment of the glazing element according to the invention. Figure 1 shows a cross-section of the glazing element. A section Z is marked there, which is shown enlarged in Figure 2. A section Y is marked there, which is shown enlarged in Figure 3.

[0105] The glazing element is designed as a laminated pane. The laminated pane is intended, for example, as a roof pane of a vehicle, in particular a passenger car. For the sake of simplicity, it is shown flat, although such vehicle roof panes are typically curved. The laminated pane is structurally formed from an outer pane 1 and an inner pane 2, which are bonded together by means of a thermoplastic intermediate layer 3. The outer pane 1 and the inner pane 2 are made of soda-lime glass and each have a thickness of, for example, 2.1 mm. The intermediate layer 3 is made of a PVB film with a thickness of, for example, 0.76 mm. The inner pane 2 is clear, while the outer pane 1 and the intermediate layer 3 are tinted in order to reduce the light transmission of the laminated pane (for example to less than 15%), as is common with vehicle roof panes.

[0106] In the installed position, the outer pane 1 faces the exterior environment of the vehicle. It has an exterior surface I facing the exterior environment and an interior surface II facing the vehicle interior. The inner pane 2 faces the vehicle interior in the installed position. It has an exterior surface III facing the exterior environment and an interior surface IV facing the vehicle interior.

[0107] The laminated pane has a surrounding, opaque edge region in which a black masking print 9 is applied to the interior-side surface II, which prevents visibility through the laminated pane. In this edge region, a light source 5 is attached to the interior-side surface IV of the inner pane 2 via a collimator 4. The light source 5 is, for example, a linear arrangement of several LEDs. The collimator 4 generates a directed, more concentrated light beam from the divergent radiation of the LEDs. The light strikes the inner pane 2 with an incidence angle of, for example, 22° (measured to the surface normal of the interior-side surface IV) and with a full width at half maximum of + / - 4°.

[0108] The inner pane 2 functions as a transparent layer within the meaning of the invention. It is designed as a flat light guide. For this purpose, the light radiated by the light source 5 through the inner pane 3 is coupled into the inner pane 2. For this purpose, the outer surface III of the inner pane 3 is provided with a reflective structure, which is irradiated by the light from the light source 5. The reflective structure is a microprism film 10, which is applied to a partial area of ​​the outer surface III. The surface of the microprism film 10 facing away from the inner pane 2 functions as the reflective surface 11 of the microprism film 10.It is designed in the form of a planar arrangement of microprisms and therefore has a plurality of sections which are inclined in different directions relative to the inner pane 2 (and its surfaces III, IV), for example at an angle of approximately 45° (the “roof angle” between adjacent sections inclined towards one another is 90°).

[0109] The microprism film 10 is constructed, for example, from two layers: a carrier layer made of PET facing the inner pane 2 and a layer made of a UV-curing polyacrylate from which the microprisms on the carrier layer are formed.

[0110] The light passing through the inner pane 2 passes through the microprism film 10 and strikes the reflective surface 11. There it is reflected back towards the inner pane 2. Depending on the inclination of the sections of the reflective surface 11, the light is deflected during reflection and radiated into the inner pane 2 in such a way that (after transmission through the inner pane 2) it strikes the interior surface IV at an angle of incidence (measured to the surface normal) that is greater than the largest critical angle of total internal reflection of the inner pane 2. This largest critical angle occurs at the exterior surface III because this is where the difference between the refractive index of the inner pane and the refractive index of the adjacent medium (PVB intermediate layer 3) is smallest. At a wavelength of 520 nm, for example, the refractive index of the inner pane 2 is 1.53 and the refractive index of the intermediate layer 3 is 1.48.This results in a critical angle of total reflection of 75.31°.

[0111] The light then spreads in the inner pane 2 like a light guide, being reflected back and forth between the surfaces III, IV (total internal reflection in each case).

[0112] To decouple the light back from the inner pane 2 and thereby create illumination, light-diffusing structures 6 made of transparent enamel are printed on the interior surface IV. When the light strikes these light-diffusing structures 6, it is scattered and thus decoupled from the inner pane 2. The light-diffusing structures 6 thus appear to the observer as luminous surfaces, which can be used, for example, for illumination or to display symbols or patterns.

[0113] Since the refractive index difference between the microprism film 10 and the intermediate layer 3 is not sufficiently pronounced for efficient reflection of the incident light, the reflective surface 11 is provided with a reflective coating 20. The reflective coating 20 is composed of (in this order, starting from the microprism film 10) a primer layer 21, a reflective layer 22, and an anti-corrosion layer 23.

[0114] The primer layer 21 is, for example, a 1 nm thick layer of nickel-vanadium (NiV). The reflective layer 22 is, for example, a 100 nm thick layer of silver (Ag). The reflective layer 22 provides the reflective properties of the reflective coating 20. The primer layer 21 primarily improves the adhesion of the reflective layer 22 to the microprism film 10. Thanks to the primer layer 21, delamination (detachment) of the reflective layer 22 does not occur, even under thermal stress. The primer layer 21 also acts as a barrier between the microprism film 10 and the reflective layer 21, thus preventing, in particular, the diffusion of chemical components of the microprism film 10 into the reflective layer 21.

[0115] The corrosion protection layer 23 is optional within the scope of the present invention. It is, for example, a 25 nm thick layer of copper (Cu), with a passivating layer of copper oxide possibly formed on the surface. The purpose of the corrosion protection layer 23 is to protect the reflective layer 22 from corrosion when the microprism film 10 is exposed to air for an extended period prior to the production of the laminated pane.

[0116] Figures 4 and 5 each show a detail of a second embodiment of the glazing element according to the invention. Figure 4 shows a cross-section of the glazing element. A section Z is marked there, which is shown enlarged in Figure 5.

[0117] The glazing element is again designed as a composite pane. The outer pane 1 with the cover print 9 and the inner pane 2 with the light source 5 and the collimator 4 are designed exactly as in the embodiment shown in Figure 1.

[0118] In contrast to the embodiment shown in Figure 1, however, it is not the inner pane 2 that serves as the transparent layer within the meaning of the invention, but rather a light guide plate 7 arranged between two thermoplastic intermediate layers 3. The intermediate layers 2 are each formed from a PVB film with a thickness of, for example, 0.38 mm or 0.76 mm. The intermediate layer 3 adjacent to the inner pane 2 is clear, while the intermediate layer 3 adjacent to the outer pane 1 is tinted.

[0119] The light guide plate 7 is, for example, a plastic sheet made of polycarbonate with a thickness of 0.7 mm. It has a first, outer surface i, which faces the external environment and the outer pane 1, and a second, interior surface ii, which faces the vehicle interior and the inner pane 2.

[0120] The light is emitted by the light source 5 through the inner pane 2, the adjacent intermediate layer 3, and the light guide plate 7, and coupled back into the light guide plate 7 via the outer surface i. For this purpose, a microprism film 10 can be arranged on the outer surface i. In the embodiment shown, however, the reflective structure with the reflective surface 8 is formed directly in the outer surface i of the light guide plate. The inclined sections of the reflective surface 8 are, for example, embossed into the outer surface i. The reflective surface 8 is provided with the reflective coating 20, which is designed in the same way as in the embodiment of Figure 3.

[0121] The light passing through the light guide plate 7 is reflected at the outer surface i, specifically by the reflective surface 8, which forms a portion of the outer surface i. Due to the inclined sections of the reflective surface 8, this light coupling occurs at such an angle that the light is totally reflected at the surfaces i, ii and thus propagates in the light guide plate 7.

[0122] To couple out the light, the light-guiding structures 6 are arranged on the interior-side surface ii of the light guide plate 7.

[0123] List of reference symbols:

[0124] (1) Outer pane

[0125] (2) Inner pane

[0126] (3) thermoplastic intermediate layer

[0127] (4) Collimator

[0128] (5) Light source

[0129] (6) light-scattering structure

[0130] (7) Light guide plate

[0131] (8) structured, reflective surface of the light guide plate 7

[0132] (9) Cover printing

[0133] (10) Microprism film

[0134] (11) reflective surface of the microprism film 10

[0135] (20) Reflective coating

[0136] (21) Primer layer of the reflective coating 20

[0137] (22) reflective layer of the reflective coating 20

[0138] (23) Corrosion protection layer of the reflective coating 20

[0139] (I) first / outer surface of the outer pane 1

[0140] (II) second / interior-side surface of the outer pane 1

[0141] (III) first / outer surface of the inner pane 2

[0142] (IV) second / interior-side surface of the inner pane 2

[0143] (i) first / outer surface of the light guide plate 7

[0144] (ii) second / interior surface of the light guide plate 7

[0145] Z enlarged section

[0146] Y enlarged section

[0147] X enlarged section

Claims

Illuminated glazing element, comprising a transparent layer (2, 7) with a first surface (III, i) and a second surface (IV, ii) and a light source (5) for generating light, which is arranged such that the light is radiated into the transparent layer (2, 7) via the second surface (IV, ii), wherein a reflective structure with a reflective surface (8, 11) is formed in the first surface (III, i) or is attached to the first surface (III, i), wherein the reflective surface (8, 11) has a plurality of sections inclined to the second surface (IV, ii) and is configured such that the light radiated into the transparent layer (2, 7) is reflected at the reflective surface (8, 11) and is at least partially coupled back into the transparent layer (2, 7) with a coupling angle that is suitablethat the coupled-in light propagates in the transparent layer (2, 7), in particular by total reflection at the first surface (III, i) and the second surface (IV, ii), and wherein the reflective surface (8, 11) is provided with a reflective coating (20) which, starting from the reflective surface (8, 11), comprises in the following order: - a primer layer (21) and - a reflective layer (22) based on a metal or a metal alloy. Illuminated glazing element according to claim 1, wherein the reflective layer (22) is based on silver or aluminum. Illuminated glazing element according to claim 1 or 2, wherein the reflective layer (22) has a thickness of 50 nm to 250 nm. Illuminated glazing element according to one of claims 1 to 3, wherein the primer layer (21) is based on a nickel alloy, preferably nickel-chromium (NiCr) or nickel-vanadium (NiV), on the basis of silicon oxide (SiO2), silicon nitride (SiSn2) or silicon oxynitride (SiO x N y), based on chromium (Cr) or a chromium alloy, based on tin (Sn) or a tin alloy, based on a titanium alloy or an oxide or nitride of a titanium alloy, based on zinc (Zn) or a zinc alloy, preferably zinc-aluminum (ZnAl), or based on copper (Cu) or a copper alloy.

5. Illuminated glazing element according to one of claims 1 to 4, wherein the primer layer (21) has a thickness of 0.5 nm to 10 nm.

6. Illuminated glazing element according to one of claims 1 to 5, wherein a corrosion protection layer (23) is arranged above the reflective layer (22).

7. Illuminated glazing element according to claim 6, wherein the corrosion protection layer (23) is based on a nickel alloy, preferably nickel-chromium (NiCr) or nickel-vanadium (NiV), based on silicon oxide (SiCh), silicon nitride (SiSn^ or silicon oxynitride (SiO x N y), based on chromium (Cr) or a chromium alloy, based on tin (Sn) or a tin alloy, based on a titanium alloy or an oxide or nitride of a titanium alloy, based on zinc (Zn) or a zinc alloy, preferably zinc-aluminum (ZnAl), or based on copper (Cu) or a copper alloy.

8. Illuminated glazing element according to claim 6 or 7, wherein the corrosion protection layer (23) has a thickness of 10 nm to 50 nm, preferably 30 nm to 40 nm.

9. Illuminated glazing element according to one of claims 1 to 8, which is designed as a composite pane and comprises an outer pane (1) and an inner pane (2) which are connected to one another via at least one thermoplastic intermediate layer (3).

10. Illuminated glazing element according to claim 9, wherein the inner pane (2) is the transparent layer.

11. Illuminated glazing element according to claim 9, wherein the transparent layer is a light guide plate (7) arranged between two intermediate layers (3).

12. Illuminated glazing element according to claim 10 or 11, wherein the reflective structure is formed as a microprism film (10) which is attached to the first surface (III, i). Illuminated glazing element according to claim 11, wherein the reflective structure is formed in the first surface (i) of the light guide plate (7). Illuminated glazing element according to one of claims 1 to 13, wherein the light is radiated into the transparent layer (2, 7) via a collimator (4). Use of an illuminated glazing element according to one of claims 1 to 14 as a window pane of a vehicle, a building, or an interior space, as a component of furniture, electrical devices, as a component of furnishings, or as a furnishing, preferably as a vehicle roof pane.

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