Illuminating glazing element with coated reflective structure for light coupling - Patent Application 20070122997

Abstract

The present invention relates to an illumination glazing element comprising a transmissive layer having a first surface and a second surface; and a light source for generating light, the light source being arranged such that light is incident on the transmissive layer through the second surface; a reflective structure having a reflective surface formed in or fixed to the first surface, the reflective surface having a plurality of sections inclined with respect to the second surface; and the reflective surface being configured such that light incident on the transmissive layer is reflected by the reflective surface and at least partially coupled back into the transmissive layer at a coupling angle suitable for the coupled light to propagate within the transmissive layer by total internal reflection, in particular at the first and second surfaces; and the reflective surface is provided with a reflective coating comprising, in the following order, starting from the reflective surface: a primer layer and a reflective layer based on a metal or metal alloy.

Description

[Technical Field]

[0001] The present invention relates to an illumination glazing element and its use. [Background technology]

[0002] Illuminating glazing elements themselves are known. For illumination, light sources, typically light-emitting diodes, can be arranged on the side edge surfaces or in the recesses of the glass panes of the glazing element, so that light is coupled into the glass panes through the side edge surfaces or the edge surfaces of the recesses, where it propagates by total internal reflection. In many cases, the light is decoupled again from the glass panes by light-scattering structures, thereby achieving illumination. The shape of the light-scattering structures can be freely selected, so that an illumination surface of any shape can be generated, for example, as a pattern. Illuminating glazing elements of this type are known, for example, from WO 2014 / 060409 or WO 2014 / 167291.

[0003] Such lighting glazing elements are important in the vehicle sector, especially roof panes through which interior illumination is possible. Illuminating glass panes are typically the inner panes of laminated panes. However, such lighting glazing elements can also be used for windows in other vehicles, as well as in windows in the building and architectural sector or in furniture. Instead of interior illumination, the illuminated surfaces formed by the light-scattering structures can also be used to display information, such as directional arrows, status indicators, warnings, price signs, etc.

[0004] The later published WO 2023144282 proposed coupling light into the light guide layer through a main surface (e.g., a glass pane or light guide plate) of the light guide layer of the glazing element, rather than through the side edge surfaces of the glazing element. For this purpose, a reflective structure having a reflective surface is attached to or formed within the first surface of the light guide layer. The reflective surface has sections that are inclined relative to one another. The reflective structure is illuminated by a light source that passes through the light guide layer, and the light is reflected by the inclined sections of the reflective surface so that the light propagates within the light guide layer by total internal reflection at the reflective surface. The reflective surface is provided with a reflective coating made of silver or aluminum. The reflective structure can, for example, be formed as a microprism film attached to the first surface of the light guide layer.

[0005] It has been found that microprismatic films provided with a silver or aluminum reflective layer can exhibit signs of delamination. The microprismatic film can sometimes peel off from the microprismatic film during aging tests, which may include exposure to temperature cycles. This can be caused by differences in the thermal expansion coefficients of the reflective layer and the microprismatic film, or by outgassing from the microprismatic film. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2014 / 060409 [Patent Document 2] International Publication No. 2014 / 167291 [Patent Document 3] International Publication No. 2023144282 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention is based on the object of providing an improved lighting glazing unit, whereby light from a light source shines through a transmissive layer onto a reflective structure and is coupled into the transmissive layer by reflection on a reflective surface of the reflective structure. To this end, it is desirable for the reflective surface to be provided with a reflective coating that is stably adherent and does not peel off from the reflective surface, in particular under thermal stress. [Means for solving the problem]

[0008] The object of the invention is achieved by an illumination glazing element according to claim 1. Preferred embodiments are evident from the dependent claims.

[0009] Within the meaning of the present invention, a lighting glazing element is a pane-like or plate-like object that includes at least one glass pane and, in particular, is structurally formed from at least one glass pane. The glazing element may be a single glass pane and may consist solely of said glass pane. Alternatively, the glazing element may be a laminated pane or insulation glazing that includes said glass pane. In the case of a laminated pane, the glass pane is bonded to another pane through a thermoplastic interlayer. In the case of insulation glazing, the glass pane is bonded to another pane in the edge region via a spacer along the periphery, resulting in a space between the panes, which is typically filled with an inert gas or evacuated. The glazing element can be used as a window pane, for example, for vehicles, buildings, or interiors. However, the glazing element can also be used as a component of furniture or electrical appliances, for example, as a door pane for a cupboard or shelf, or as a pane for an oven door. The glazing element can also be used as a fixture, for example, as a display panel in a bar or nightclub.

[0010] The lighting glazing element according to the invention comprises or includes at least one transmissive layer and a light source intended and suitable for generating light. The transmissive layer has a first surface (main surface), a second surface (main surface) and side edge surfaces extending therebetween. The light source is arranged such that light is (at least partially) incident on the transmissive layer through the second surface. The light passes through the transmissive layer and strikes the first surface.

[0011] A reflective structure having a reflective surface is formed in or affixed to the first surface. The reflective surface has a plurality of sections inclined relative to the second surface, and the reflective surface is configured such that light incident on and passing through the transmissive layer is reflected from the reflective surface and at least partially coupled back into the transmissive layer. The light is reflected by the reflective surface into the transmissive layer and coupled into the transmissive layer at a coupling angle suitable for the coupled light to at least partially propagate within the transmissive layer (at least a portion of the coupled light) by total internal reflection, particularly at the first and second surfaces of the transmissive layer.

[0012] More precisely, - the light passes through the transparent layer and strikes the first surface, and is reflected by a reflective structure, if one is formed on the first surface; in this case, the reflective surface of the reflective structure is a partial area of ​​the first surface, and the light is reflected from this partial area; - the light passes through the transparent layer and exits the transparent layer again through the first surface and is reflected by the reflective surface of a reflective structure if one is fixed to the first surface; preferably, the light leaving the transparent layer passes through the reflective structure and is reflected by its surface facing away from the transparent layer, which forms the reflective surface.

[0013] The reflective surface is provided with a reflective coating. According to the present 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 a specified order starting from the reflective surface. Thus, the primer layer is 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.

[0014] The primer layer according to the present invention particularly improves the adhesion of the reflective coating to the reflective surface. As a result, delamination can be avoided, and the reflective coating can stably adhere to the reflective surface even after aging tests. The primer layer also functions as a barrier between the reflective structure and the metal-containing reflective layer. As a result, for example, the diffusion of chemical components or oxygen from the reflective structure into the reflective layer can be prevented, which effectively reduces the aging and corrosion of the reflective layer. These are significant advantages of the present invention.

[0015] Each layer of the reflective coating is preferably a thin layer, which in the sense of the present invention refers to a layer having a thickness of less than 1 μm, and which is in particular deposited by vapor deposition.

[0016] In the sense of the present invention, if a first layer is deposited above a second layer, this means that the first layer is further from the reflective surface than the second layer, and if a first layer is deposited below a second layer, the first layer is closer to the reflective surface than the second layer.

[0017] If a layer of the reflective coating is based on a material, this means in the sense of the present invention that the layer consists largely of this material, i.e. that it comprises at least 50% by weight, preferably at least 70% by weight, particularly preferably at least 90% by weight of the layer. The layer may also contain dopants and / or impurities, preferably in proportions of up to 10% by weight.

[0018] The reflective layer of the reflective coating is preferably based on silver or aluminum. This achieves particularly good reflective properties. The proportion of the reflective layer made of the metal is preferably at least 90%, particularly preferably at least 95%, and very particularly preferably at least 99%. The reflective layer may also contain dopants or impurities.

[0019] The reflective layer preferably has a thickness of 50 nm to 250 nm, which allows particularly good reflective properties to be achieved.

[0020] When the reflective layer is formed based on silver, its thickness is preferably 50 nm to 150 nm, particularly preferably 80 nm to 120 nm, for example, about 100 nm. When the reflective layer is formed based on aluminum, its thickness is preferably 150 nm to 250 nm, particularly preferably 180 nm to 220 nm, for example, about 200 nm. This is advantageous in terms of reflective properties without the need to use too much material. In the sense of the present invention, thickness always refers to the geometric layer thickness, not the optical layer thickness, which is the product of the geometric thickness and the refractive index.

[0021] The primer layer of the reflective coating is preferably nickel alloys, preferably based on nickel chromium (NiCr) or nickel vanadium (NiV), - Silicon oxide (SiO2), silicon nitride (Si3N4) or silicon oxynitride (SiO x N y ) as a base, - Based on chromium (Cr) or chromium alloys, - Based on tin (Sn) or tin alloys, - based on titanium alloys or oxides or nitrides of titanium alloys, based on zinc (Zn) or zinc alloys, particularly preferably based on zinc aluminum (ZnAl), or - Based on copper (Cu) or copper alloys By using these materials, good results are achieved in terms of the adhesion of the reflective coating and the barrier effect of the primer layer.

[0022] The primer layer preferably has a thickness of 0.5 nm to 10 nm. If the primer layer is based on a metal or metal alloy, in particular on one selected from the aforementioned metals and metal alloys, its thickness is particularly preferably 0.5 nm to 5 nm, and very particularly preferably 1 nm to 3 nm. If the primer layer is based on an oxide, nitride or oxynitride, in particular on one selected from the aforementioned oxides, nitrides and oxynitrides, its thickness is particularly preferably 5 nm to 10 nm.

[0023] It is particularly advantageous if the primer layer is based on a metal or metal alloy and has a relatively thin thickness of 0.5 nm to 5 nm, in particular 1 nm to 3 nm. In this case, the propagation direction of the light from the light source is not particularly affected. Particularly preferred metals and metal alloys are those mentioned above, namely: - nickel alloys, in particular nickel chromium (NiCr) or nickel vanadium (NiV), - Chromium (Cr) or chromium alloys, - tin (Sn) or tin alloys, - titanium alloys, - zinc (Zn) or zinc alloys, in particular zinc aluminium (ZnAl), or - Copper (Cu) or copper alloy is.

[0024] The primer layer is preferably in direct contact with the reflective surface of the reflective structure, and particularly preferably in direct contact with the reflective layer.

[0025] In one advantageous embodiment, the reflective coating includes an anticorrosion layer disposed above the reflective layer. Thus, the reflective layer is disposed between the primer layer and the anticorrosion layer. The anticorrosion layer protects the underlying layers, particularly the reflective layer, from corrosion. This is particularly advantageous when the reflective structure is not stored airtight in the glazing element immediately after application of the reflective coating, but is initially stored or exposed to air for a long period during the manufacture of the glazing element. In such cases, the metal-based reflective layer may corrode, particularly oxidize due to atmospheric oxygen. Such corrosion is prevented or at least significantly delayed by the anticorrosion layer.

[0026] The anticorrosion layer is preferably nickel alloys, preferably based on nickel chromium (NiCr) or nickel vanadium (NiV), - Silicon oxide (SiO2), silicon nitride (Si3N4) or silicon oxynitride (SiO x N y ) as a base, - Based on chromium (Cr) or chromium alloys, - Based on tin (Sn) or tin alloys, - based on titanium alloys or oxides or nitrides of titanium alloys, based on zinc (Zn) or zinc alloys, particularly preferably based on zinc aluminum (ZnAl), or - Based on copper (Cu) or copper alloys This gives good results.

[0027] The anticorrosion layer preferably has a thickness of 10 nm to 50 nm, particularly preferably 30 nm to 40 nm, which provides good corrosion protection without the need to use excessively large amounts of material.

[0028] In particular, if the anticorrosion layer is formed based on a metal or metal alloy, a passivating oxide layer may be formed on the (exposed) surface of the anticorrosion layer (facing away from the reflective layer).

[0029] In principle, the reflective layer can have other layers. However, in a preferred embodiment, the reflective layer is in direct contact with the primer layer (and the anticorrosion layer, if present). Further layers can be provided above the conductive layer (if no anticorrosion layer is present) or above the anticorrosion layer (if present), which can, for example, improve the bonding of the glazing element to adjacent components or act as a barrier thereto.

[0030] It is particularly preferred that the reflective layer consists of only the layers mentioned herein (primer layer, conductive layer, and optionally anticorrosion layer) and has no further layers. Thus, the reflective layer preferably consists of only the primer layer and the reflective layer, or only the primer layer, the reflective layer, and the anticorrosion layer.

[0031] The transparent layer of a glazing element can also be referred to as a transparent coating, a light-guiding layer, or a light-guiding coating. It is typically a transparent glass or polymer layer. The transparent layer is preferably a rigid layer. For example, it can be formed as a glass pane or plate, or as a plastic pane or plate. The glass or plastic pane can form the 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-guiding film can also be embedded in the glazing element and function as a transparent layer, for example, a PET foil with a thickness of 30 μm to 200 μm. The transparent layer distributes the light emitted by the light source across the surface of the glazing element, similar to a light guide.

[0032] The specified transparency of the transmission layer particularly relates to the wavelength or wavelength range of the light source. The transmission layer preferably has a light transmittance of at least 70%, particularly preferably at least 80%, and very particularly preferably at least 90% for light from the light source.

[0033] The first surface of the transparent layer faces away from the light source, and the second surface of the transparent layer faces the light source. The light source illuminates the transparent layer, with light entering the transparent layer through the second surface, passing through the transparent layer, and striking the first surface of the transparent layer.

[0034] The second surface is preferably smooth (flat or curved), and the first surface is preferably also smooth and parallel to the second surface, except in the area of ​​the reflective surface if a reflective structure is formed directly on the first surface.

[0035] The reflective structure serves to couple light into the transmissive layer and is arranged on a first surface of the transmissive layer opposite the light source, in particular fixed to or formed in the first surface of the transmissive layer, so that light passing through the transmissive layer strikes the reflective structure and is (at least partially) reflected back towards the transmissive layer by its reflective surface provided with a reflective coating.

[0036] Typically, the reflective structure is not provided over the entire first surface of the transmissive layer, but only in the partial area of ​​the first surface that is illuminated by the light source.

[0037] The reflective structure can include or be formed from a separate component of the glazing unit, in particular a microprism film. This component is attached, for example glued, to the first surface. The reflective surface of the reflective structure faces away from the transmissive layer. This component is transparent. Light from the light source exits the transmissive layer again through the first surface, passes through this component, hits the reflective surface, is reflected there, passes through the component again, and re-enters the transmissive layer through the first surface.

[0038] A microprism film is a flexible, particularly foil-like, polymer film having a smooth surface facing the transparent layer, particularly disposed thereon, and a structured surface facing away from the transparent layer. The structured surface is in the form of a planar array of prisms with dimensions in the micrometer range, which prism surfaces form inclined sections of the reflective surface. The microprisms (provided with a reflective coating) act in particular as reflecting prisms, reflecting light that strikes them in a direction that depends on the inclination angle of the prism surface and the angle of incidence of the light. Microprism films are commercially available and can be purchased or produced during the production of the glazing element according to the invention. The edge length of the individual microprisms is preferably between 10 μm and 250 μm, particularly preferably between 20 μm and 100 μm, e.g., about 30 μm.

[0039] The microprism film may be formed in multiple layers, for example, a microprism film having a substrate layer is commonly used, for example, based on polyethylene terephthalate (PET), on which the microprism film is formed from a UV-curable polyacrylate.

[0040] The microprism film is transparent and preferably has a light transmittance of at least 70°, particularly preferably at least 80°, and very particularly preferably at least 90° relative to the light from the light source. To minimize reflection losses at the interface between the transparent layer and the microprism film, it is advantageous if the difference between the refractive index of the transparent layer and the refractive index of the microprism film is as small as possible. Preferably, the difference in refractive index is at most 0.02 (for a wavelength of 550 nm), particularly preferably at most 0.01. If the refractive index of the transparent layer and the refractive index of the microprism film differ, the microprism film preferably has a higher refractive index than the transparent layer, which is advantageous for efficient light coupling.

[0041] Instead of a flexible microprism film, a rigid microprism plate, ie, a rigid plastic plate having a planar array of microprisms, can also be used.

[0042] However, the reflective structure can also be formed directly on the first surface of the transmissive layer. To this end, a partial area of ​​the first surface is formed as a reflective surface. This is relatively easy to achieve, especially when the transmissive layer is a polymer layer such as a plastic pane or plate. The light is reflected directly off the first surface and reflected back into the transmissive layer without leaving the layer. If the reflective surface with the reflective coating is formed to be only partially reflective, some of the light will naturally leave the transmissive layer through the first surface and will not be reflected.

[0043] According to the invention, the reflective surface of the reflective structure has sections that are inclined toward the second surface of the transparent layer. This means that these sections are not parallel to the second surface, but are arranged at an angle greater than 0° to the second surface. The sections are arranged at an angle between 0° and 90°, preferably between 28° and 60°, or between 30° and 60°, very particularly preferably between 30° and 50°, in particular between 40° and 50°, for example about 45°, to the second surface. This is the absolute value of the specific angle. The sections can be inclined in different directions.

[0044] The sections are also preferably inclined towards each other, meaning that adjacent sections are inclined towards each other, i.e. they are not parallel to each other but are arranged at an angle between 0° and 180° to each other.

[0045] The section of the reflective surface is preferably substantially flat. The inclination of the section of the reflective surface relative to the second surface of the transmissive layer determines the angle at which the reflected light is reflected back into the transmissive layer.

[0046] The first and second surfaces of the transmissive layer are the interfaces with an adjacent medium, which can be either the ambient atmosphere or another layer or coating of the glazing element. Typically, the adjacent medium has a different refractive index than the transmissive layer. If the adjacent medium has a lower refractive index than the transmissive layer, this gives rise to a critical angle for total internal reflection, which is

number

[0047] In particular, a section of the reflective surface is tilted such that at least a portion of the light strikes the second surface at an angle (angle of incidence) greater than the critical angle for total internal reflection and is reflected back into the transparent layer. The light beam is totally reflected by the second surface at a reflection angle corresponding to the angle of incidence. The light strikes the first surface at this angle of incidence, where it is totally reflected again. The light does not spread, but instead propagates through the transparent layer with virtually no loss as a result of repeated total internal reflections, where it is reflected in a zigzag pattern between the two surfaces of the transparent layer. As is common in geometric optics, the angle of incidence is the angle that a light beam incident on a surface makes with respect to the surface normal at the point of impact. The angle of reflection, like the critical angle for total internal reflection, is also determined with respect to the surface normal.

[0048] In certain embodiments of the present invention, the medium adjacent to the first surface of the transmissive layer is different from the medium adjacent to the second surface. This is the case, for example, in a laminated pane consisting of two laminated glass panes, where one of the glass panes is used as the transmissive layer. In this case, one surface of the glass pane is adjacent to the ambient air, and the other surface is adjacent to the thermoplastic interlayer of the laminated pane. Therefore, different critical angles for total internal reflection occur at the two surfaces. In this case, the reflective surface is configured so that at least a portion of the light strikes the second surface at an angle (angle of incidence) greater than the relatively large critical angle for total internal reflection and is reflected back into the transmissive layer. These light components propagate through the transmissive layer as a result of repeated total internal reflections at both surfaces.

[0049] Light propagates through the transmissive layer until it strikes a side edge surface of the transmissive layer where it is decoupled, or until it strikes a light-scattering structure on one of the two surfaces of the transmissive layer, which scatters the light and breaks the total internal reflection, causing the light to be decoupled from the transmissive layer through that surface.

[0050] The glazing element comprises 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 that are set within, encompass or cover part of the visible spectral range. However, the light source can also have a broad emission band that covers the entire visible spectral range. The one or more emission bands, and thus the color of the emitted light, can be freely selected according to the requirements of a particular application.

[0051] The glazing element can have a single light source or multiple separate light sources whose light is coupled into the transmissive layer at different points.

[0052] The light source preferably comprises at least one light emitting diode (LED). The light source may be a single light emitting diode, but is preferably an array of several light emitting diodes. The array is preferably arranged in a common housing, for example as a linear array of light emitting diodes arranged in rows. The electroluminescent material of the light emitting diode may be, for example, an inorganic or organic semiconductor. In the latter case, this is also called an organic light emitting diode (OLED).

[0053] Light from the light source can be emitted directly into the glazing unit or through an optical element such as a lens. In an advantageous embodiment, the light from the light source is incident on the glazing element or the transmissive layer through a collimator. The collimator generates a light beam from the typically divergent light beam of the light source, preferably with a substantially parallel beam path, but at least with a less divergent, i.e., more focused, beam path. This has the advantage that the entire light beam is incident on the glazing element at the same angle of incidence, which, in particular, together with the inclination of the section of the reflective surface of the reflective structure, ensures that the maximum proportion of light is coupled into the transmissive layer, and this coupling occurs in such a way that total internal reflection occurs at the surface. As a result, the luminous efficiency is optimized.

[0054] In the simplest case, the collimator is a kind of converging lens with the light source at its focus. The collimator can be made, for example, from glass or transparent plastic, in particular polycarbonate (PC) or polymethyl methacrylate (PMMA). If the light source is made as an array of several light-emitting diodes, a separate collimator can be provided for each light-emitting diode. Preferably, however, one collimator is used for the entire LED array. In the case of a linear LED array, for example, a rod-shaped collimator can be used, the length of which corresponds at least to the length of the LED array.

[0055] If the glazing element is a laminated pane, the collimator is preferably attached, for example glued, to the exposed (inner) surface of the inner pane. The light source is attached, for example glued, screwed or fitted into the collimator, to the surface of the collimator facing away from the laminated glass. If the glazing element is a monolithic pane, in particular a single glass pane, the collimator is preferably attached, for example glued, to the second surface.

[0056] The collimated light beam is preferably incident on the glazing element at a non-zero angle of incidence. The angle of incidence is defined as the angle relative to the surface normal of the exposed surface of the glazing element facing the light source, e.g., the angle relative to the surface normal of the inner surface of an inner pane of a laminated pane. The angle of incidence is selected so that the maximum percentage of light (preferably substantially all light) is coupled into the transmissive layer, where total internal reflection occurs on the surface of the transmissive layer, thereby propagating the light within the transmissive layer. The appropriate angle of incidence lies in an angular range that depends largely on the refractive index of the medium adjacent to the transmissive layer (as well as the numerical aperture of the light guide). The appropriate angle of incidence also depends on the orientation of the inclined section of the reflective surface relative to the light source and, in the case of a separate component with a reflective surface, particularly a microprism film, the refractive index of the material of said component. The orientation (inclination) of the section of the reflective surface of the reflective structure determines the direction of the reflected light (the angle of incidence corresponds to the angle of reflection). Those skilled in the art can select the appropriate angle of incidence for a particular application using simple optical calculations.

[0057] A non-zero angle of incidence is achieved, for example, by the surface of the collimator facing the transmissive layer being arranged not parallel to the surface facing the light source, on which the light source is fixed.

[0058] In a preferred embodiment, the transmissive layer comprises at least one light-scattering structure suitable for decoupling light from the transmissive layer through the first and / or second surface of the transmissive layer. The light-scattering structure is disposed on or in contact with one of the first or second surfaces. When light propagating within the transmissive layer strikes a light-scattering structure, the light is scattered, thereby preventing total internal reflection and causing the scattered light to decouple and leave the transmissive layer.

[0059] The light-scattering structures appear as the luminous surface of the glazing element. They can be used, for example, to illuminate the interior or to display symbols or patterns that may serve to convey information or may simply be provided for aesthetic reasons. The light-scattering structures can be present in a single continuous area of ​​the glass pane or in multiple distinct areas. Any shape or pattern can be realized by the light-scattering structures.

[0060] 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 on a support foil that is fixed to the first or second surface, for example, by adhesive bonding. If the glazing element according to the present invention is a laminated pane, the light-scattering structure can be applied to the surface of the thermoplastic intermediate layer that contacts the transparent layer. Alternatively, the light-scattering structure (e.g., applied to a support foil) can be inserted between the transparent layer and the intermediate layer.

[0061] In an advantageous embodiment, the light-scattering structure is formed as an imprint, in particular on one of the surfaces of the transparent layer or, in the case of a laminated pane, on the surface of an adjacent intermediate layer facing the transparent layer. If the transparent layer is made of glass (e.g., the inner pane of a laminated pane or a glass integrated light guide plate), the imprint thereon is preferably formed as a light-scattering enamel. This enamel can be applied, for example, using a screen printing method. The enamel preferably contains glass frit, which is baked onto the surface of the glass layer, resulting in a roughened and thus light-scattering surface. The imprint on the polymer layer (e.g., the intermediate layer or the polymeric light guide plate) can be realized by printing a light-scattering printing paste onto the surface of the polymer layer, for example, using a screen printing method. In an advantageous embodiment, the light-scattering structure is transparent, so that the see-through nature of the glazing element is not significantly limited. Therefore, the imprint (enamel or printing paste) preferably does not contain a pigment. However, opaque or translucent light-scattering structures containing pigments, such as white structures, are also conceivable.

[0062] However, the light-scattering structures can also be formed by roughening the surface of the transparent layer. This roughening can be performed mechanically (for example, by grinding) or by laser processing. Laser processing has the advantage, especially in the case of laminated panes, that if the light-scattering structures are to be arranged inside the laminated pane, they can also be introduced into the finished laminated pane, since the laser radiation can also be focused on the inner surface of the laminated pane. Laser processing also makes it possible to form the light-scattering structures inside the transparent layer rather than on the surface.

[0063] However, light-scattering structures are not necessary within the scope of the present invention: applications are also envisaged in which light decoupling is performed through the side edge surfaces of the transmissive layer, in which case no light-scattering structures are required on the first or second surface.

[0064] The glazing element may be a monolithic pane, in particular a single glass pane. Structurally, the glazing element is formed by only a single glass pane, which also functions as a transmission layer within the meaning of the present invention. The glass pane has a thickness of, for example, 1 mm to 10 mm and is preferably made of soda-lime glass. The glass pane is preferably made of clear glass without any tint or coloring. A single glass pane is typically used as a window pane for separating the interior from the exterior environment. It has an inner surface facing the interior in the installed position and an outer surface facing the exterior environment in the installed position. The inner surface is preferably the second surface within the meaning of the present invention, to which a light source is fixed. The outer surface is the first surface within the meaning of the present invention, to which a reflective structure is provided. Instead of a single glass pane, in principle, a single polymer pane made of clear, transparent plastic can also be used.

[0065] However, in an advantageous embodiment, the glazing element according to the invention is formed as a laminated pane. The laminated pane according to the invention comprises an outer pane and an inner pane, which are joined to each other through a thermoplastic interlayer. The outer pane and the inner pane each have an inner surface that faces the interior in the installed position and an outer surface that faces the external environment in the installed position. The outer and inner surfaces are typically designed to be see-through, with side edge surfaces extending between them. The inner surface of the outer pane and the outer surface of the inner pane face each other and are joined to each other by at least one interlayer. The outer pane and the inner pane are preferably made of glass, in particular soda-lime glass, and each have a thickness of 0.5 mm to 10 mm, preferably 1 mm to 5 mm. The interlayer (or each interlayer, if there are several) is preferably formed from a thermoplastic foil, for example based on polyvinyl butyral (PVB), ethylene vinyl acetate copolymer (EVA), or polyurethane (PU), and has a thickness of, for example, 0.3 mm to 1.0 mm. Instead of glass panes, in principle polymer panes made of clear transparent plastic can also be used as the outer and / or inner panes. The light source is preferably fixed to the inner surface of the inner pane.

[0066] If a polymer foil or layer is based on a material, this means, within the meaning of the present invention, that the foil or layer consists largely of said material, i.e., the proportion of said material is more than 50% by weight, preferably more than 60% by weight. The foil or layer may also contain other ingredients such as plasticizers, stabilizers, UV or IR blockers, etc.

[0067] The inner pane is preferably made of clear glass to ensure efficient transmission of light, while the outer pane and any intermediate layers between the transparent and outer panes can be tinted or colored.

[0068] In a first preferred variant of the laminated pane, the outer or inner pane is a transparent layer within the meaning of the present invention, and the inner pane is particularly preferred. The inner surface of the inner pane (or outer pane) is particularly the second surface within the meaning of the present invention, and the outer surface is the first surface with a reflective structure. The reflective structure preferably comprises or is formed from a separate component, in particular a microprism film. This component is preferably fixed to the outer surface of the inner pane (or outer pane). This component may be glued to the surface or (in the case of the inner pane) fixed there by contact pressure of at least one intermediate layer.

[0069] In a second preferred variant, the laminated 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 an outer pane and an inner pane. The light guide plate is a transmissive layer within the meaning of the present invention, and the first surface within the meaning of the present 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 relatively thin glass pane having 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 may 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 range specified above for glass light guide plates.

[0070] The laminated pane may also have a flexible light guide film (light guide foil) as a transmissive layer instead of a light guide plate.

[0071] The reflecting structure may include or be formed from a separate component, particularly a microprism film, that is secured to a first surface, particularly the outer surface, of the light guide plate. The component may be glued to the light guide plate or secured thereto by contact pressure with an adjacent interlayer.

[0072] Alternatively, the reflective structure can be formed directly on the first surface of the light guide plate (which serves as the transmissive layer). This is particularly easy to achieve when the light guide plate is made of plastic. A reflective surface with an inclined surface can be produced, for example, by removing material in areas of the first surface, for example by milling or grinding, by laser processing, or by chemical treatment such as etching. Alternatively, the reflective surface can be formed by additionally applying a polymer material, for example made of UV-curable polyacrylate, to the first surface.

[0073] The laminated pane preferably has an opaque masking area through which it is impossible to see through. This masking area is preferably arranged along the periphery of the edge area of ​​the laminated pane and frames the central transparent see-through area like a frame. This is particularly common in vehicle windows. The masking area is formed in particular by an opaque element arranged on the outer side of the reflective structure, preferably between the reflective structure and the outer pane. The masking area can be formed by an opaque cover imprint, which is particularly preferably applied to the inner surface of the outer pane. Alternatively, a tinted intermediate layer (or a tinted section of the intermediate layer) can form the opaque element.

[0074] The glazing element may be flat or curved in one or more spatial directions.

[0075] The reflective coating is preferably deposited on the reflective surface by vapor deposition, such as chemical vapor deposition (CVD), plasma-enhanced chemical vapor deposition (PECVD) or atomic layer deposition (ALD). Physical vapor deposition (PVD), such as evaporative deposition, is particularly preferred, and cathode sputtering ("sputtering"), in particular magnetic field-assisted cathode sputtering ("magnetron sputtering"), is very particularly preferred.

[0076] If the glazing element is formed as a laminated pane, its manufacture can use known lamination methods, such as autoclave, vacuum bag, vacuum ring, calendering, vacuum laminator, or combinations thereof, and the outer and inner panes are typically bonded under the influence of heat, vacuum, and / or pressure.

[0077] The present invention also includes the use of the glazing element according to the present invention as a windowpane for a vehicle. A particularly preferred application is a vehicle roofpane used for lighting the interior of the vehicle. In principle, the vehicle may be any land vehicle, ship, or aircraft, preferably a passenger car, truck, or rail vehicle. The glazing element can also be used in buildings, for example as a windowpane, glass facade, or glass door in outdoor or indoor areas, in particular as a windowpane for buildings or indoors. The glazing element can also be used as a component of furniture, electrical appliances, as a component of equipment, or as equipment.

[0078] The present invention will now be described in more detail with reference to the drawings and exemplary embodiments, which are schematic and not to scale, and which are not intended to limit the invention in any way. [Brief explanation of the drawings]

[0079] [Figure 1] 1 is a cross-sectional view of one embodiment of a pane according to the present invention. [Figure 2] FIG. 2 is an enlarged view of section Z shown in FIG. [Figure 3] FIG. 3 is a further enlarged view of section Y shown in FIG. 2. [Figure 4] 3 is a cross-sectional view of a further embodiment of a glazing element according to the invention; [Figure 5] FIG. 5 is an enlarged view of X shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0080] Figures 1, 2 and 3 each show details of a first embodiment of a glazing element according to the invention. Figure 1 shows a cross section of the glazing element. Section Z is shown in Figure 1, which is enlarged in Figure 2. Section Y is shown in Figure 2, which is enlarged in Figure 3.

[0081] The glazing element is formed as a laminated pane. The laminated pane is designed, for example, as a vehicle roof pane, particularly a passenger car roof pane. Such vehicle roof panes are typically curved, but are shown flat for simplicity. The laminated pane consists of an outer pane 1 and an inner pane 2, which are joined to each other via a thermoplastic interlayer 3. The outer pane 1 and the inner pane 2 are made of soda-lime glass, e.g., each having a thickness of 2.1 mm. The interlayer 3 is formed, for example, from a PVB foil having a thickness of 0.76 mm. The inner pane 2 is clear, and the outer pane 1 and the interlayer 3 are tinted to reduce the light transmittance of the laminated pane (e.g., to less than 15%), as is customary for vehicle roof panes.

[0082] In the installed position, the outer pane 1 faces the exterior environment of the vehicle. This outer pane 1 has an outer surface I facing the exterior environment and an inner surface II facing the interior of the vehicle. In the installed position, the inner pane 2 faces the interior of the vehicle. This inner pane 2 has an outer surface III facing the exterior environment and an inner surface IV facing the interior of the vehicle.

[0083] The laminated pane has an opaque edge region along its periphery, within which a black cover imprint 9 is applied to the inner surface II, preventing visibility through the laminated pane. Within this edge region, a light source 5 is fixed to the inner surface IV of the inner pane 2 through a collimator 4. The light source 5 is, for example, a linear array of LEDs. The collimator 4 generates a more focused, highly directional light beam from the divergent radiation of the LEDs. The light strikes the inner pane 2 with a full width at half maximum of + / - 4° at an angle of incidence of, for example, 22° (measured relative to the surface normal of the inner surface IV).

[0084] The inner pane 2 serves as a transmissive layer within the meaning of the present invention. This transmissive layer is provided as a planar light guide. For this purpose, light emitted from 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 that is illuminated by the light from the light source 5. This reflective structure is a microprism film 10 applied to a partial area of ​​the outer surface III. The surface of the microprism film 10 facing away from the inner pane 2 serves as the reflective surface 11 of the microprism film 10. It is formed in the form of a planar array of microprisms and therefore has several sections inclined in different directions relative to the inner pane 2 (and its surfaces III and IV), for example at an angle of about 45° (the "roof angle" between adjacent sections inclined relative to each other is 90°).

[0085] The microprism film 10 is made up of two layers, for example a PET support layer facing the inner pane 2 and a UV curable polyacrylate layer from which the microprisms are formed on the support layer.

[0086] Light passing through the inner pane 2 passes through the microprism film 10 and strikes the reflective surface 11, where it is reflected back toward the inner pane 2. Depending on the inclination of the section of the reflective surface 11, the light is deflected upon reflection and is incident on the inner pane 2 such that (after passing through the inner pane 2) it strikes the inner surface IV at an angle of incidence (measured relative to the surface normal) greater than the critical angle for maximum occurrence of total internal reflection on the inner pane 2. This maximum critical angle occurs on the outer surface III because there is the smallest difference between the refractive index of the inner pane and that of the adjacent medium (PVB interlayer 3). For example, at a wavelength of 520 nm, the refractive index of the inner pane 2 is 1.53, and the refractive index of the interlayer 3 is 1.48. This results in a critical angle for total internal reflection of 75.31°.

[0087] The light then propagates in the inner pane 2 like a light guide and is reflected in a zigzag pattern between surfaces III and IV (total internal reflection, respectively).

[0088] To decouple light from the inner pane 2 and achieve illumination, light-scattering structures 6 made of transparent enamel are printed on the inner surface IV. When light strikes these light-scattering structures 6, the light is scattered and thus decoupled from the inner pane 2. In this way, the light-scattering structures 6 appear to the observer as a luminous surface, which can be used, for example, for illumination or to display symbols or patterns.

[0089] Because the refractive index difference between the microprism film 10 and the intermediate layer 3 is not significant enough to efficiently reflect incident light, the reflective surface 11 is provided with a reflective coating 20. The reflective coating 20 is composed of (starting from the microprism film 10) a primer layer 21, a reflective layer 22, and an anticorrosion layer 23.

[0090] The primer layer 21 is, for example, a nickel vanadium (NiV) layer having a thickness of 1 nm. The reflective layer 22 is, for example, a silver (Ag) layer having a thickness of 100 nm. 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. The primer layer 21 prevents delamination (peeling) of the reflective layer 22 even when subjected to thermal stress. The primer layer 21 also functions as a barrier between the microprism film 10 and the reflective layer 21, thereby, among other things, preventing the diffusion of chemical components of the microprism film 10 into the reflective layer 21.

[0091] Within the scope of the present invention, the anti-corrosion layer 23 is optional. It may be, for example, a 25 nm thick layer of copper (Cu) with a passivation layer of copper oxide on its surface. The role of the anti-corrosion layer 23 is to protect the reflective layer 22 from corrosion if the microprism film 10 is exposed to air for a long period of time before the laminate pane is manufactured.

[0092] Figures 4 and 5 each show a detail of a laminated pane according to the invention. Figure 4 shows a cross section of a glazing element. Section Z is shown in Figure 4 and is enlarged in Figure 5.

[0093] The glazing element is again formed as a laminated pane: the outer pane 1 with the cover imprint 9 and the inner pane 2 with the light source 5 and collimator 4 are formed exactly the same as in the embodiment according to FIG.

[0094] 1, however, it is not the inner pane 2 that serves as a transmissive layer within the meaning of the invention, but rather the light guide plate 7 arranged between two thermoplastic interlayers 3. The interlayers 2 are each formed from a PVB foil having a thickness of, for example, 0.38 mm or 0.76 mm. The interlayer 3 adjacent to the inner pane 2 is clear, whereas the interlayer 3 adjacent to the outer pane 1 is tinted.

[0095] The light guide plate 7 is a plastic pane, for example made of polycarbonate, with a thickness of 0.7 mm. It has a first outer surface i facing the external environment and the outer pane 1, and a second inner surface ii facing the interior of the vehicle and the inner pane 2.

[0096] Light is emitted from the light source 5, passes through the inner pane 2, the adjacent intermediate layer 3 and the light guide plate 7, and is coupled back into the light guide plate 7 through the outer surface i. For this purpose, a microprism film 10 can be disposed on the outer surface i. However, in the illustrated embodiment, a reflective structure having a reflective surface 8 is formed directly on the outer surface i of the light guide plate. The sloping section of the reflective surface 8 is, for example, embossed into the outer surface i. The reflective surface 8 is provided with a reflective coating 20 formed similarly to the embodiment of FIG. 3.

[0097] Light passing through the light guide plate 7 is reflected at the outer surface i by a reflective surface 8 forming a partial area of ​​the outer surface i. Due to the inclined section of the reflective surface 8, this light coupling is performed at an angle such that the light propagates within the light guide plate 7 by total internal reflection at surfaces i and ii.

[0098] A light guiding structure 6 is arranged on the inner surface ii of the light guide plate 7 for decoupling the light. [Explanation of symbols]

[0099] (1) Outer pane (2) Inner pane (3) Thermoplastic intermediate layer (4) Collimator (5) Light source (6) Light scattering structure (7) Light guide plate (8) Structured reflective surface of light guide plate 7 (9) Cover imprint (10) Microprism film (11) Reflective surface of microprism film 10 (20) Reflective coating (21) Primer layer of reflective coating 20 (22) Reflective layer of reflective coating 20 (23) Anti-corrosion layer of reflective coating 20 (I) First / outer surface of outer pane 1 (II) Second / inner surface of outer pane 1 (III) First / outer surface of inner pane 2 (IV) Second / inner surface of inner pane 2 (i) the first / outer surface of the light guide plate 7 (ii) the second / inner surface of the light guide plate 7 Z Zoomed Section Y Enlarged section X Enlarged section

Claims

1. 1. An illumination glazing element, comprising a transmissive layer (2,7) having a first surface (III,i) and a second surface (IV,ii), and a light source (5) for generating light, the light source (5) being arranged such that the light is incident on the transmissive layer (2,7) through the second surface (IV,ii), a reflecting structure having a reflecting surface (8, 11) formed in or fixed to the first surface (III, i), the reflecting surface (8, 11) having a plurality of sections inclined with respect to the second surface (IV, ii), and the reflecting surface (8, 11) being configured such that the light incident on the transmissive layer (2, 7) is reflected by the reflecting surface (8, 11) and is at least partially coupled back into the transmissive layer (2, 7) at a coupling angle suitable for the coupled light to propagate within the transmissive layer (2, 7) by total internal reflection, in particular at the first surface (III, i) and the second surface (IV, ii); The reflective surfaces (8, 11) are provided with a reflective coating (20), which is applied in the following order starting from the reflective surfaces (8, 11): a primer layer (21) and a reflective layer (22) based on a metal or metal alloy; 1. A lighting glazing element, including:

2. 2. The lighting glazing element according to claim 1, wherein the reflective layer (22) is formed on a silver or aluminum basis.

3. 3. Illumination glazing element according to claim 1 or 2, wherein the reflective layer (22) has a thickness of 50 nm to 250 nm.

4. The primer layer (21) is based on a nickel alloy, preferably nickel chromium (NiCr) or nickel vanadium (NiV), and is preferably formed of silicon oxide (SiO ２ ), silicon nitride (Si ３ N ４ ) or silicon oxynitride (SiO ｘ N ｙ 4. The lighting glazing element according to claim 1, wherein the lighting glazing element is made on a basis of chromium (Cr) or a chromium alloy, on a basis of tin (Sn) or a tin alloy, on a basis of titanium alloys or oxides or nitrides of titanium alloys, on a basis of zinc (Zn) or a zinc alloy, preferably on a basis of zinc aluminum (ZnAl), or on a basis of copper (Cu) or a copper alloy.

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

6. 6. The lighting glazing element according to claim 1, wherein an anticorrosion layer (23) is arranged above the reflective layer (22).

7. The anticorrosion layer (23) is based on a nickel alloy, preferably nickel chromium (NiCr) or nickel vanadium (NiV), and is preferably formed of silicon oxide (SiO ２ ), silicon nitride (Si ３ N ４ ) or silicon oxynitride (SiO ｘ N ｙ 7. The lighting glazing element according to claim 6, wherein the lighting glazing element is made on a basis of chromium (Cr) or a chromium alloy, on a basis of tin (Sn) or a tin alloy, on a basis of titanium alloys or oxides or nitrides of titanium alloys, on a basis of zinc (Zn) or a zinc alloy, preferably on a basis of zinc aluminum (ZnAl), or on a basis of copper (Cu) or a copper alloy.

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

9. 9. The lighting glazing element according to any one of claims 1 to 8, wherein the lighting glazing element is formed as a laminated pane and comprises an outer pane (1) and an inner pane (2), the outer pane (1) and the inner pane (2) being bonded to each other through at least one thermoplastic intermediate layer (3).

10. 10. The lighting glazing element according to claim 9, wherein the inner pane (2) is the transmissive layer.

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

12. 12. Illumination glazing element according to claim 10 or 11, wherein the reflective structure is formed as a microprism film (10) fixed to the first surface (III, i).

13. 12. Illumination glazing element according to claim 11, wherein the reflective structure is formed in the first surface (i) of the light guide plate (7).

14. 14. Illumination glazing element according to any one of the preceding claims, wherein the light is incident on the transmissive layer (2, 7) through a collimator (4).

15. 15. Use of an illumination glazing element according to any one of claims 1 to 14 as a window pane in a vehicle, building or interior, as a component of furniture, an electrical appliance, as a component of equipment or as a piece of fittings, preferably as a roof pane for a vehicle.

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