Illuminated pane-like glass element having reduced emittance via the lateral edge

Abstract

The present invention relates to an illuminated glass element, comprising a glass pane (2) that has a first surface (III), a second surface (IV) and a lateral edge surface (e) extending therebetween, which - is fitted with at least one light source (5), which is suitable for coupling-in light into the glass pane (2) such that the light propagates in the glass pane (2), in particular by total reflection on the first surface (III) and the second surface (IV), and - is provided with at least one light-scattering structure (6), which is suitable for coupling-out said light out of the glass pane (2) via the first surface (III) and / or the via the second surface (IV), characterised in that the glass pane (2) is provided, in a peripheral edge region, at least in part, with a light trap, which is suitable for reducing the emittance of the light via the lateral edge surface (e), wherein the light trap is made of a light-scattering or light-refracting layer (7) on the first surface (III) and an opaque element (8) on the second surface (IV).

Description

[0001] Illuminated disc-like glass element with reduced radiation over the side edge

[0002] The invention relates to an illuminated glass element with at least one glass pane and its use.

[0003] Illuminated glass panes 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 the glass pane, 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. Light-scattering structures can be used to couple the light back out of the glass pane, thus 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 glass panes of this type are known, for example, from WO2014 / 060409A1 or WO2014 / 167291 A1.

[0004] In the automotive sector, such illuminated glass panes are particularly interesting as roof windows, through which the interior can be illuminated. The illuminated glass pane typically represents the inner pane of a laminated glass pane. However, such illuminated glass panes can also be used for other vehicle windows or even 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, or to create aesthetic patterns.

[0005] The problem with conventional illuminated glass panes of this type is that part of the light spreads out to the circumferential side edge of the glass pane and is output there. This means that not only the light-diffusing structures are illuminated, but also the side edge. On the one hand, this is disruptive because the emission of light over the side edge is undesirable and irritating for the viewer. It can even result in the glass pane no longer meeting legal requirements, particularly in the area of ​​vehicle windows, where glare for the driver or other road users must be prevented. On the other hand, the light output at the side edge also leads to a loss of light, which is then no longer available for the intended output at the light-diffusing structures. The intensity of the illumination or the efficiency is therefore reduced.

[0006] The unpublished international patent application PCT / EP2023 / 051960 proposes providing the side edge surface with a reflective layer that reflects light back into the glass pane, thereby preventing radiation from passing over the side edge surface. The reflective layer is, in turn, covered with an opaque material that serves to mask and mechanically and chemically protect the light-reflecting layer.

[0007] There is a continuing need for illuminated glass panes of the type mentioned above, in which the unwanted radiation of light via the side edge surface is prevented or at least reduced. The present invention is based on the object of providing an illuminated glass element with such an improved illuminated glass pane.

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

[0009] The illuminated glass 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 glass element can be a single glass pane and structurally consist only of said glass pane. Alternatively, the glass element can 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 insulating glazing, 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 glass element can be used as a window pane, for example as a window pane in vehicles, buildings, or interiors.The glass 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 glass element can also be used as a furnishing item, for example, as a display panel in bars or nightclubs.

[0010] The illuminated glass element according to the invention comprises at least one glass pane. The glass pane has a first surface (main surface) and a second surface (main surface), which are typically substantially parallel to each other, as well as a side edge surface extending between the first and second surfaces.

[0011] The glass element or pane can be flat or curved in one or more directions. In the latter case, one of the surfaces is typically concave and the other convex. The side edge surface can be flat. However, it is common practice to grind the side edge surface to minimize the risk of injury. The side edge surface is then curved or rounded, in particular convexly curved or rounded.

[0012] The glass pane is equipped with at least one light source capable of coupling the light emitted by it into the glass pane such that the light propagates in the glass pane between the first surface and the second surface, in particular by total internal reflection at the first surface and the second surface. As is usual with illuminated glass panes of this type, the glass pane is provided with at least one light-scattering structure capable of coupling said light out of the glass pane 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.When the light propagating in the glass pane hits the light-scattering structure, it is scattered, which prevents total reflection, so that the scattered light is coupled out of the glass pane and leaves the glass pane.

[0013] According to the invention, the glass pane is provided, at least in sections, with a light trap in a peripheral edge region, which is suitable for at least reducing or even completely preventing the emission of light across the side edge surface of the glass pane. In other words, at least a section of the peripheral edge region of the pane is provided with the light trap. The light trap is formed from a light-scattering or light-diffracting layer on the first surface of the glass pane and an opaque element on the second surface of the glass pane. The light-scattering or light-diffracting layer and the opaque element can be applied directly to the respective surface or can be in contact with it.

[0014] In conventional illuminated glass panes, a portion of the light propagating through the glass pane strikes the side edge surface and is then coupled out of the glass pane via the side edge surface. The light is therefore also emitted via the side edge surface, which is undesirable. This is prevented or at least reduced in the glass element according to the invention by the light trap arranged in the edge region. The light-scattering or -diffracting layer on the first surface of the glass pane interrupts total internal reflection when light rays strike it. The light scattered or diffracted by said layer strikes the opaque element and is absorbed by it. The light trap thus intercepts the light before it reaches the side edge surface of the glass pane.At least a portion of the light that would hit the side edge surface and be coupled out via it without the light trap is blocked and, in a sense, absorbed by the light trap. This prevents radiation via the side edge surface. With a suitable design of the glass element, it is even possible to intercept all of the light before it hits the side edge surface, thus preventing radiation entirely. This is the great advantage of the present invention.

[0015] If the glass element according to the invention is a window pane (for example of a vehicle, a building, an interior space, a piece of furniture or a piece of furnishing), it is intended to be inserted into a window opening and there to separate an interior space from an external environment. The glass pane then has an external surface and an internal surface. For the purposes of the invention, the term "external surface" refers to the main surface which is intended to face the external environment in the installed position. For the purposes of the invention, the term "internal surface" refers to the main surface which is intended to face the interior space in the installed position.The first surface of the glass pane (in the sense of the invention, the surface with the light-scattering or diffracting layer of the light trap) can be the outside surface of the glass pane, in which case the second surface (in the sense of the invention, the surface with the opaque element of the light trap) is the inside surface. Alternatively, the first surface of the glass pane can be the inside surface and the second surface the outside surface.

[0016] The glass pane is provided with a light source suitable for coupling light into the glass pane. The light can be coupled in, in particular, via the side edge surface of the glass pane, via the edge surface of a recess in the glass pane, or with the aid of a light coupling means via one of the surfaces of the glass pane. The light is radiated into the glass pane and strikes one of the surfaces of the glass pane, which represent interfaces to an adjacent medium. The glass pane typically has a higher refractive index (e.g., soda-lime glass: 1.52 at a light wavelength of 589 nm) than the adjacent media (e.g., the surrounding atmosphere, in particular air: 1.00 at a light wavelength of 589 nm). Since there is a transition from an optically denser to an optically less dense medium, a critical angle OCT of total internal reflection can be determined as a T= arcsin(— ), where ni is the refractive index of the glass pane and n2 is the refractive index of the surroundings. For example, the critical angle of total internal reflection at a transition from soda-lime glass to air and a light wavelength of 589 nm is OCT = 41°.

[0017] The light is typically radiated into the glass pane by the light source over a certain angular range. The light rays can strike a surface of the glass pane from the interior of the glass pane. A light ray strikes the said surface of the glass pane at an angle of incidence, which depends on the angle at which the light ray was radiated. Two situations must be distinguished:

[0018] If the angle of incidence is smaller than the critical angle of total internal reflection, the light beam is refracted at the surface and mostly enters the area surrounding the glass pane. This situation occurs particularly close to the point of input. Only a small portion is reflected at the surface at an angle of reflection corresponding to the angle of incidence and then strikes the opposite surface, where a large portion of the remaining light intensity is again refracted and leaves the glass pane. This light is therefore lost for its intended use, namely the illumination of the glass pane due to outcoupling at the light-scattering structures. The unwanted radiation near the point of input can optionally be prevented by an opaque element, such as a cover print or a sticker.If the angle of incidence is greater than the critical angle of total internal reflection, the light beam is totally reflected at the surface with an angle of reflection that corresponds to the angle of incidence. The light does not escape into the environment and, as a result of repeated total internal reflection, spreads essentially without loss within the glass pane, being reflected back and forth between the two surfaces of the glass pane. Those portions of the light that hit the light-scattering structure are extracted, upon which the intended illumination of the glass pane is based. Portions of the light that are not extracted by the light-scattering structure reach the edge region of the glass pane, where they are extracted via the side edge surface or intercepted by the light trap according to the invention.

[0019] 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.

[0020] The glass pane can be conceptually divided into a circumferential edge region, which borders on the circumferential side edge surface, and a central region surrounded by the edge region. The light-scattering structure is arranged in the central region and the light trap according to the invention in the edge region. The edge region is arranged in a strip-like manner along the side edge surface or the outline of the glass pane; it can also be referred to as an edge strip. The dimension of the edge strip that extends along the side edge surface (or parallel to the side edge surface) can be referred to as the length of the edge region and the dimension that extends perpendicular to the side edge can be referred to as the width of the edge region. The width of the edge region corresponds to the extent to which the edge region extends from the side edge surface towards the central region.For example, the edge area has a width of 10 cm or only 7 cm or 5 cm.

[0021] The light trap according to the invention is arranged in the edge region of the glass pane. However, it does not have to completely cover the edge region. The components of the light trap (light-scattering / diffractive layer and opaque element) do not have to extend over the entire length or the entire width of the edge region. The light trap extends in a strip-like manner over at least a longitudinal section of the edge region. Thus, there is at least one longitudinal section of the edge region along which the light-scattering / diffractive layer and the opaque element are present, with the light-scattering / diffractive layer and the opaque element extending independently of one another over part of the width (width section) of the edge region or over the entire width of the edge region. The light-scattering / diffractive layer and the opaque element can independently of one another directly border the side edge surface or be spaced apart from it.

[0022] The light-scattering or diffracting layer and the opaque element are arranged in the same length of the edge region. However, they do not have to cover the same width. In other words, they do not have to be aligned in the direction of view through the glass pane, but can be offset from each other (relative to the width dimension of the edge region).

[0023] It is particularly advantageous if the light trap is formed completely around the edge area, interrupted only at points where light is coupled in. This reduces the radiation across the entire side edge. However, it is also conceivable for only one or more sections of the edge area to be equipped with the light trap, while other sections remain free. This can be chosen, for example, if only the radiation across a portion of the side edge is to be reduced.

[0024] The light-scattering or diffracting layer is particularly suitable for deflecting the light striking it toward the opaque element. The light deflected by the light-scattering or diffracting layer is (at least partially) reflected back into the glass pane at an angle of reflection that is smaller than the angle of incidence. Consequently, it does not strike the side edge surface of the glass pane, but rather the opaque element, where it is absorbed. The light-scattering or diffracting layer and the opaque element are suitably positioned relative to one another for this purpose. The width and relative arrangement of the light-scattering / diffracting layer and the opaque element depend on the design of the glass element in the specific application. They depend, among other things, on the thickness of the glass pane, the wavelength of the light, the material of the glass pane and its surroundings, as well as the design and refractive index of the light-scattering or diffracting layer.The light-scattering or light-diffracting layer is strip-like and extends along (a portion of) the side edge of the first surface, in particular parallel to the side edge. In other words, the light-scattering or light-diffracting layer extends strip-like along at least a portion of the side edge surface of the glass pane. Analogous to the edge region, the dimension of the light-scattering or light-diffracting layer that extends along the side edge can be referred to as the length of the light-scattering or light-diffracting layer, and the dimension that extends perpendicular to the side edge can be referred to as the width. The width of the light-scattering or light-diffracting layer is preferably constant. The strip-like light-scattering or light-diffracting layer, in turn, has two side edges that extend along the length dimension and limit the width dimension.One of these side edges faces the side edge of the first surface and the other side edge faces away from the side edge of the first surface.

[0025] The width of the light-scattering or light-diffracting layer is preferably from 10 mm to 65 mm, particularly preferably from 30 mm to 50 mm. The side edge of the light-scattering or light-diffracting layer facing the side edge of the first surface is preferably at a distance of 0 mm to 35 mm from the side edge of the first surface, particularly preferably from 5 mm to 20 mm or from 10 mm to 20 mm. This distance can also be referred to as the distance of the light-scattering or light-diffracting layer from the side edge surface. At a distance of 0 mm, the light-scattering or light-diffracting layer directly borders the side edge of the first surface.At a distance greater than 0 mm, the light-scattering or light-diffracting layer is spaced from the side edge of the first surface, so that a region of the first surface exists between the light-scattering or light-diffracting layer and the side edge of the glass pane that is not covered by the light-scattering or light-diffracting layer. The side edge of the light-scattering or light-diffracting layer facing away from the side edge of the first surface is preferably spaced from the side edge of the first surface by 10 mm to 100 mm, particularly preferably by 35 mm to 70 mm.

[0026] The light-scattering or diffracting layer is in direct contact with the first surface of the glass pane to exert its effect. It can be applied directly to the first surface. If the glass element is a laminated pane in which the first surface of the glass pane faces the intermediate layer, it can also be applied to that surface of the thermoplastic intermediate layer that faces the first surface of the glass pane and is in contact with it. Alternatively, it can be inserted between the first surface of the glass pane and the intermediate layer.

[0027] In one embodiment of the invention, the light-scattering or light-diffracting layer is formed as an optical grating. Optical gratings are periodic structures for diffracting light (diffraction gratings). They have parallel, line-like structures through which a plurality of slits are formed. Gratings work by diffracting light: the light from the individual slits interferes and forms an interference pattern. The light is thus deflected, with the degree of deflection depending on the wavelength of the light and the grating constant. The grating constant is the period of the grating, i.e., the distance between adjacent line-like structures. The grating constant and the geometric arrangement of the optical grating and the opaque element are suitably coordinated, taking into account the wavelength of the light source, so that the largest possible proportion of the light diffracted by the grating strikes the opaque element.The optical grating is, in particular, a reflection grating. With reflection gratings, diffraction effects arise through reflection off a suitably prepared, reflective layer. The line-like structures can be introduced into a suitable (reflective) substrate, for example, by etching, scribing, or exposure. The optical grating is preferably provided as a finished component and attached to the first surface. Optical gratings are commercially available and can be purchased. The optical grating can, for example, be glued to the first surface. In the case of a laminated pane in which the first surface of the glass pane faces the intermediate layer, the optical grating can be inserted between the first surface of the glass pane and the thermoplastic layer.Alternatively, it is also possible to provide the first surface with a suitable (reflective) coating and form the optical grating within it. The coating can be, for example, a dielectric layer sequence or a layer sequence with metal-containing layers; the grating can be formed, for example, by laser structuring the coating.

[0028] In a further embodiment of the invention, the light-scattering or light-diffracting layer is formed as an imprint. The imprint can be printed directly on the first surface of the glass pane. In the case of a laminated pane in which the first surface of the glass pane faces the intermediate layer, the imprint can alternatively be printed on the surface of the thermoplastic layer that faces the first surface of the glass pane and is in contact with it.

[0029] The print acts primarily as a light-scattering structure. This can be achieved in any way, for example, by adding light-scattering additives to the printing paste. Suitable light-scattering additives include glass frits, which can optionally be baked into the first surface of the glass pane. Glass beads or other micrometer-sized particles can also be used as light-scattering additives.

[0030] The color of the print is irrelevant. Therefore, any pigments or dyes can optionally be added to the printing paste.

[0031] In a further embodiment of the invention, the light-scattering or light-diffracting layer is formed as a microprism film. A microprism film comprises a substrate (in particular a flexible substrate, for example in the form of a plastic film) with a planar arrangement of a plurality of prisms with dimensions in the micrometer range. The microprisms act in particular as reflection prisms and reflect the light striking them at an angle of reflection that deviates from the angle of incidence, in particular is smaller than the angle of incidence, so that the light is directed onto the opaque element. Due to the dimensions in the micrometer range, diffraction and refraction also occur at the prisms, so that the microprism film can be regarded as a light-scattering or light-diffracting layer. The microprism film is preferably provided as a finished component and attached to the first surface. Microprism films are commercially available and can be purchased.The microprism film can, for example, be glued to the first surface. In the case of a laminated pane where the first surface of the glass pane faces the interlayer, the microprism film can be inserted between the first surface of the glass pane and the thermoplastic layer.

[0032] 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 approximately 30 pm, 50 pm, or 70 pm. In a particularly advantageous embodiment, the microprism film is provided with a light-reflecting coating, for example a silver coating or a dielectric layer sequence. The coating is applied to the surface of the microprism film facing away from the glass pane to increase the reflective effect. Instead of a flexible microprism film, a rigid plastic plate with a planar arrangement of microprisms can also be used.

[0033] In a further embodiment of the invention, the light-scattering or light-diffracting layer is formed as a structured coating. The structured coating is preferably a microperforated dielectric thin-film coating. A SiO2 coating is particularly preferred. The coating preferably has a layer thickness of less than 1 pm, particularly preferably from 50 nm to 500 nm. Microperforation is understood to mean (in particular periodic) interruptions in the coating with dimensions in the nanometer or micrometer range, which are introduced into the coating, for example, by laser processing. The light-scattering or light-diffracting effect of such a coating is based in particular on local differences in the refractive index. The coating can be applied directly to the first surface of the glass pane, for example by chemical or physical vapor deposition.In the case of a laminated pane where the first surface of the glass pane faces the interlayer, the coating can alternatively be applied to that surface of the thermoplastic interlayer that faces the glass pane and is in contact with it. Alternatively, the coating can be provided pre-formed on a carrier film, for example, a PET film, and inserted between the first surface of the glass pane and the interlayer.

[0034] The opaque element is particularly suitable for (at least partially) absorbing the light deflected by the light-scattering or diffracting layer. The opaque element is also strip-shaped and extends along (a region of) the side edge of the second surface, in particular parallel to the side edge. In other words, the opaque element extends strip-like along at least a portion of the side edge surface of the glass pane. Analogous to the edge region and the light-scattering or diffracting layer, the dimension of the opaque element that extends along the side edge can be referred to as the length of the opaque element, and the dimension that extends perpendicular to the side edge can be referred to as the width. The width of the opaque element is preferably constant. The strip-shaped opaque element, in turn, has two side edges that extend along the length dimension and delimit the width dimension.One of these side edges faces the side edge of the second surface, and the other side edge faces away from the side edge of the second surface. The opaque element is preferably arranged at least in the same length section of the edge region as the light-scattering or diffractive layer. This means that the opaque element has at least the same length as the light-scattering or diffractive layer and is arranged such that the opaque element completely overlaps the light-scattering or diffractive layer. The opaque element can have the same length as the light-scattering or diffractive layer and be arranged in the same length section of the edge region, wherein the opaque element and the light-scattering or diffractive layer extend completely along said length section.However, the opaque element can also extend beyond the light-scattering or diffracting layer on one or both sides. In both cases, the light deflected by the light-scattering or diffracting layer can be effectively absorbed by the opaque element.

[0035] The side edge of the opaque element that faces the side edge of the second surface is particularly preferably at a distance of 0 mm from the side edge of the second surface, and therefore preferably borders directly on the side edge of the second surface or on the side edge surface. However, the opaque element can also be spaced from the side edge of the second surface, preferably by a maximum of 20 mm, so that the distance between the side edge of the opaque element that faces the side edge of the second surface and the side edge of the second surface is preferably from 0 mm to 20 mm. This distance can also be referred to as the distance of the opaque element from the side edge surface. The required width of the opaque element depends in particular on the light-deflecting effect of the light-scattering or light-diffracting layer.Typically, the side edge of the opaque element facing away from the side edge of the second surface can be spaced from the side edge of the second surface by a distance less than the distance of the side edge of the light-scattering or diffracting layers facing away from the side edge of the first surface from the side edge of the first surface. The opaque element extends less far toward the central region of the glass pane than the light-scattering or diffracting layer, which is typically sufficient for the light to be deflected by the light-scattering or diffracting layer toward the side edge surface, with an angle of reflection that is smaller than the angle of incidence, but still greater than zero.However, the opaque element can also extend as far or even further in the direction of the central region than the light-scattering layer, so that the side edge of the opaque element, which faces away from the side edge of the second surface, has a distance from the side edge of the second surface that is equal to or even greater than the distance of the side edge of the light-scattering or diffracting layers, which faces away from the side edge of the first surface, from the side edge of the first surface.

[0036] In typical applications, the distance between the side edge of the opaque element facing away from the side edge of the second surface and the side edge of the second surface is from 20 mm to 100 mm. The width of the opaque element is, for example, from 10 mm to 100 mm, preferably from 20 mm to 70 mm.

[0037] The opaque element is preferably attached directly to the second surface of the glass pane. In one embodiment of the invention, the opaque element is formed as a print on the second surface of the glass pane. A printing paste containing a pigment or dye is applied to the second surface by any printing method, for example by screen printing or pad printing. The pigment or dye causes the opacity of the opaque element and is present in sufficient quantities so that the opaque element is not transparent to the light from the light source deflected by the light-scattering or diffractive layer, but rather absorbs said light. The color of the opaque element is irrelevant. A black color may be preferred for aesthetic reasons, but in principle the opaque element can have any color.

[0038] The printing paste can be dried after printing and adhere to the glass pane purely adhesively. Alternatively, an enamel-like print can be used, as is commonly used for masking on vehicle windows. The printing paste contains glass frits that are fired into the glass surface after printing, providing a particularly stable bond to the glass surface.

[0039] In a further embodiment of the invention, the opaque element is designed as an opaque component made of rubber or plastic, which is attached, for example, glued, to the second surface of the glass pane. The opaque component can be flexible, elastic, or even rigid, like a film.

[0040] In principle, opaque coatings are also conceivable as an opaque element, which are applied, for example, to the second surface of the glass pane by chemical or physical vapor deposition. In the case of a laminated pane where the second surface of the glass pane faces the intermediate layer, the opaque element can also be formed on the surface of the thermoplastic intermediate layer that faces the glass pane and is in contact with it (for example, as an opaque print) or can be inserted between the intermediate layer and the second surface of the glass pane (for example, as an opaque component made of rubber or plastic).

[0041] During operation, the light source emits visible light, i.e., electromagnetic radiation in the visible spectral range, specifically in the range from 380 nm to 780 nm. The light source can have one or more emission bands located in the visible spectral range and covering part of it. However, the light source can also have a broad emission band that 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.

[0042] The glass pane can contain a single light source or multiple light sources whose light is coupled into the glass pane at different locations. The light from the light source can be coupled into the glass pane directly or via an optical element, such as a lens.

[0043] The light source is preferably a light-emitting diode (LED). The electroluminescent material of the LED 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).

[0044] The coupling of the light from the light source into the glass pane can be carried out in different ways, with three embodiments being particularly preferred.

[0045] In a first preferred embodiment, the light source is assigned to a recess in the glass pane. The glass pane therefore has a recess. This recess is preferably a hole, i.e. a passage, which extends between the first and the second surface of the glass pane. Alternatively, however, the recess can also be a depression in the manner of a blind bore (bag-like depression), which extends from the first surface or the second surface into the glass pane, but without reaching the opposite main surface, which would result in a passage. The blind bore preferably extends from a surface into the glass pane which forms an exposed surface of the glass element according to the invention. The light source can then be inserted subsequently and easily replaced in the event of a defect.In the case of a laminated pane, the exposed surface is that surface of the glass pane facing away from the intermediate layer. The recess can be created in the glass pane, for example, by mechanical drilling or laser processing. The recess is preferably round, but can in principle have any desired shape, for example a polygonal shape. This refers to the base area of ​​the recess in the plane of the at least one surface of the glass pane over which the recess is introduced into the glass pane. The recess has the overall shape of a cylinder, preferably a vertical cylinder. The cylinder is preferably a circular cylinder (circular base area), but can also have any other base areas, for example an elliptical base area (elliptical cylinder) or a polygonal base area (prism).

[0046] The recess, whether as a feedthrough or a depression, is defined by a circumferential edge surface extending between the main surfaces of the glass pane. In the case of a feedthrough, this is the only boundary surface of the recess. In the case of a pocket-like depression, a further boundary surface is present, which faces the main surface of the glass pane to which the depression does not extend and which, as it were, forms the bottom of the blind bore. If the glass element comprises several light sources, a separate recess is preferably provided for each light source. However, several light sources, for example with different emission colors, can also be arranged in the same recess.

[0047] In this embodiment, the light source is assigned to the said edge surface of the recess and is suitable for coupling light into the glass pane via this edge surface. The light source itself can be arranged in the recess so that it is in the plane defined by the glass pane and the emitted light hits the edge surface directly. The light source can, for example, be clamped into the recess or glued to the edge surface. It is also conceivable for the light source to be located in a housing or holder and fixed there, with the housing or holder being inserted into the recess, preferably with a precise fit. Alternatively, however, it is also possible for the light source not to irradiate the edge surface directly, but rather for the radiation to be first deflected.It is conceivable that the light source is located in a housing, with one part of the housing being inserted into the recess, while another part of the housing is located outside the recess. The light source is positioned in the part of the housing outside the recess, and the light is redirected by reflective surfaces or waveguides in the housing such that it illuminates the edge surface of the recess. Said housing is preferably attached to an exposed surface of the glass pane and extends from there into the recess.

[0048] In this embodiment, the light trap, i.e., the light-scattering or diffractive layer and the opaque element, is particularly preferably formed completely circumferentially in the edge region. This means that the light-scattering or diffractive layer and the opaque element each extend along the entire length of the edge region and are each formed in a frame-like manner without interruption. Thus, there is no longitudinal section of the edge region that is not provided with the light-scattering or diffractive layer and the opaque element. This reduces or prevents the emission of light across the entire side edge, which is particularly advantageous.

[0049] In a second preferred embodiment, the light source is assigned to one of the two surfaces of the glass pane. The light source is arranged on one of the surfaces and radiates light via this surface into the glass pane. On the other surface, opposite the light source, a light coupling means is arranged, which is suitable for coupling the light striking the light coupling means through the glass pane onto the light coupling means via the said other surface (i.e., the surface on which the light coupling means is arranged) into the glass pane. The light coupling means can be designed, for example, as a microprism film, as a structured plastic film, or as a plastic plate with a planar arrangement of microprisms. The light coupling means reflects the light back into the glass pane, but at a changed angle that deviates from 0° to the surface normal.The light is refracted at the surface of the glass pane, and at least a portion of the resulting light in the glass pane strikes the opposite surface at an angle of incidence greater than the critical angle of total internal reflection, thereby coupling the light into the glass pane. The light source is preferably located on an exposed surface of the glass pane or glass element so that it can be retrofitted and easily replaced in the event of a defect.

[0050] In this embodiment, too, the light trap, i.e., the light-scattering or light-diffracting layer and the opaque element, is particularly preferably formed completely circumferentially in the edge region. This reduces or prevents the emission of light across the entire side edge, which is particularly advantageous.

[0051] In a third preferred embodiment, the light source is assigned to the side edge surface of the glass pane and is suitable for coupling light into the glass pane via the side edge surface. The light emitted by the light source can hit the side edge surface directly. The light source can be located to the side of the inner pane in the plane defined by the glass pane. For this purpose, the light source can be attached directly to the side edge surface, for example, glued or clamped. Alternatively, the light source can also be located in a housing or holder and fixed there, wherein the housing or holder is attached to the glass pane, for example, glued or clamped, in such a way that the light source irradiates the side edge surface. However, it is also possible for the light source not to irradiate the side edge surface directly, but rather for the radiation to be first deflected.It is conceivable for the light source to be located in a housing containing reflective surfaces or waveguides through which the light beam path is shaped. This housing is attached to the glass pane in such a way that the beam path guides the light to the side edge surface of the glass pane. The light source itself then does not have to be located to the side of the glass pane in the plane defined by the glass pane, but can, for example, be arranged in front of or behind the glass pane in the viewing direction. The said housing is preferably attached to an exposed surface of the glass pane and extends from there to the side edge surface of the glass pane.

[0052] In this embodiment, the light trap, i.e. the light-scattering or light-diffracting layer and the opaque element, is particularly preferably formed circumferentially in the edge region and is only interrupted at the point or points at which the light from the light source(s) is coupled into the glass pane. Each light source is therefore assigned a length of the edge region of the glass pane through which the light is coupled. In these lengths, the light-scattering or light-diffracting layer and the opaque element are not present. All other lengths of the edge region are provided with the light-scattering or light-diffracting layer and the opaque element along their entire length. This reduces or prevents the emission of light across the entire side edge because it is prevented from emitting across the side edge either by the light trap or the light source.

[0053] A combination of the embodiments described above is also conceivable, wherein several light sources are present whose light is coupled into the glass pane in different ways.

[0054] If the light from the light source is coupled in via the side edge surface of the glass pane or via the edge surface of a recess in the glass pane, then in a particularly advantageous embodiment a central diaphragm is arranged between the light source and the side edge surface or the edge surface of the recess. A central diaphragm is a diaphragm which blocks a central region of the beam cone of the light source so that a central region of the side edge surface or edge surface is not irradiated with light. The side edge surface or edge surface can then be divided into three regions, with two regions (edge ​​regions) each bordering a surface of the glass pane and the third region (the said middle region) being arranged between the other two sections. The light is coupled in via at least one of the edge regions, preferably via both.

[0055] The beam cone of the light source can be divided into three angle groups: a first angle group in which the light is coupled into the glass pane in such a way that it hits the surfaces of the glass pane at an angle of incidence smaller than the critical angle of total internal reflection, so that it is not subject to total internal reflection and is lost via the surfaces; a second angle group in which the light is coupled into the glass pane in such a way that it hits the surface of the glass pane at an angle of incidence greater than the critical angle of total internal reflection and consequently spreads through the glass pane by total internal reflection, but the angle of incidence is sufficiently small for the light to hit the light-scattering or light-diffracting layer before it reaches the side edge surface of the glass pane; the beam trap acts on this angle group and prevents or reduces radiation via the side edge surface.a third angle group in which the light is coupled into the glass pane in such a way that it a) passes through the glass pane and exits again at the opposite side edge surface without hitting a surface of the glass pane, or b) hits the surface of the glass pane at an angle of incidence greater than the critical angle of total internal reflection, but which is so large that the light reaches the opposite side edge surface after a few total internal reflections without hitting the light-scattering or diffracting layer (the light-scattering or diffracting layer is effectively skipped); the beam trap cannot act on this angle group.

[0056] The central baffle is preferably sized to partially or completely block the light from the third angle group. This can further reduce light emission from the side edges of the glass pane.

[0057] The glass pane is also provided with a light-scattering structure designed to couple the coupled light out of the glass pane via the first and / or second surface. The light-scattering structure has direct contact with one of the surfaces, so that the light propagating through the glass pane strikes it. The light-scattering properties of the light-scattering structure prevent total internal reflection. The light-scattering structure represents a scattering center at which the light is scattered and therefore not totally reflected. Since scattering is fundamentally non-directional, at least some of the scattered light leaves the glass pane. This can be used to illuminate or display information.

[0058] The area of ​​the glass pane covered by the light-diffusing structure appears to the observer as a luminous surface. This can be used, for example, for illumination (e.g. of an interior space) or for creating a display to show information or to create aesthetically pleasing luminous surfaces or patterns. The luminous structure can be present in a single, contiguous area of ​​the glass pane or in several separate areas. The light-diffusing structure can enable any shape or pattern to be realized. The light-diffusing structure is arranged in particular in the central area of ​​the glass pane, which is surrounded by the edge area with the light trap. The light-diffusing structure can be applied directly to the first or second surface of the glass pane or formed there.Alternatively, the light-diffusing 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 glass element according to the invention is a laminated pane, the light-diffusing structure can be applied to the surface of the thermoplastic intermediate layer that is in contact with the glass pane. Alternatively, the light-diffusing structure (for example, applied to a carrier film) can be inserted between the glass pane and the intermediate layer.

[0059] 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 glass pane or - in the case of a composite pane - on the surface of the intermediate layer facing the glass pane. A print on the glass pane is preferably in the form of a light-scattering enamel. This enamel can be printed, for example, using a screen printing process. It preferably contains glass frits, which are fired into the surface of the glass pane, creating a roughened and therefore light-scattering surface. A print on the intermediate layer can be realized by printing a surface of a thermoplastic film with a light-scattering printing paste, for example using a screen printing process.During the production of the laminated pane, the film is inserted between the outer and inner panes to form the intermediate layer, with the printed surface facing the glass pane, particularly in direct contact with the glass pane. In an advantageous embodiment, the light-scattering structure is transparent, so that it does not significantly restrict visibility through the glass pane. The print (the enamel or printing paste) therefore preferably contains no pigment. However, opaque or semi-transparent light-scattering structures containing pigments are also conceivable, for example, white structures.

[0060] Light-diffusing structures can also be created by roughening the relevant surface of the glass pane or the interlayer. 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-diffusing 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, for example, through the transparent glass pane. Laser processing also makes it possible to create the light-diffusing structure inside the glass pane rather than on a surface.

[0061] The glass pane is preferably made of soda-lime glass, which is common for window panes. However, the glass pane can also be made of other types of glass (e.g., borosilicate glass, quartz glass, aluminosilicate glass). The thickness of the glass pane can vary widely. Preference is given to panes with a thickness in the range of 0.5 mm to 10 mm, more preferably 1 mm to 5 mm. The glass pane is preferably clear to allow the light to spread effectively within the inner pane.

[0062] In one development of the invention, the glass element according to the invention is a laminated pane. In addition to the glass pane, the laminated pane comprises a further pane which is connected to the glass pane via a thermoplastic intermediate layer. The further pane likewise has a first surface, a second surface and a circumferential side edge surface running between them. If the glass element is a window pane, one of the panes can be referred to as the outer pane and the other pane as the inner pane. For the purposes of the invention, the inner pane refers to the pane of the laminated pane which, in the installed position, faces the interior. The outer pane refers to the pane facing the outside environment. The interior-side surface of the outer pane and the outside surface of the inner pane face each other and the thermoplastic intermediate layer and are connected to one another by the thermoplastic intermediate layer.

[0063] In principle, the glass pane with the light source, the light-diffusing structure, and the light trap can be the outer pane or the inner pane of the laminated pane. Preferably, the glass pane is the inner pane, and the further pane is the outer pane. This advantageously illuminates the interior. The first surface or the second surface of the glass pane can face the intermediate layer. Particularly preferably, the light-diffusing structure is applied to or formed on the outer surface of the glass pane (inner pane), because it is then protected within the laminate. The same applies to a light-diffusing structure on the surface of the intermediate layer in contact with the inner pane.

[0064] The additional pane (preferably the outer pane) is preferably made of glass, in particular soda-lime glass. However, the additional pane can also be made of other types of glass (e.g., borosilicate glass, quartz glass, aluminosilicate glass) or transparent plastics (e.g., polymethyl methacrylate or polycarbonate). The thickness of the outer pane and the inner pane is preferably between 0.8 mm and 5 mm, preferably between 1.4 mm and 2.5 mm.

[0065] In an advantageous embodiment, the further pane (outer pane) and / or the intermediate layer are tinted. The inner pane (glass pane with light source, light-diffusing structure, and light trap) is preferably clear. The light can then advantageously propagate within the inner pane, and the illuminated light-diffusing structure advantageously appears clearly against the tinted background. The outer pane and / or the intermediate layer are preferably tinted such that the light transmission of the composite pane in the visible spectral range is in the range from 0% to 80%, preferably from 2% to 20%, most preferably from 4% to 12%. With a light transmission of 0%, the composite pane serves only for illumination, while visibility through it is not possible.In a particularly advantageous embodiment, in particular when the composite pane is a vehicle roof pane, the outer pane is tinted and has a light transmission of 0% to 95% or of 2% to 80%, the intermediate layer is tinted and has a light transmission of 0% to 95% or of 2% to 80% and the inner pane is clear and has a light transmission of more than 80%, in particular more than 90%.

[0066] The thermoplastic intermediate layer comprises at least one layer of a thermoplastic bonding material, which preferably contains ethylene-vinyl acetate (EVA), polyvinyl butyral (PVB), or polyurethane (PU), or mixtures or copolymers or derivatives thereof, particularly preferably PVB. The intermediate layer is typically formed from at least one thermoplastic film. The thickness of the film is preferably from 0.3 mm to 2 mm, with standard thicknesses of 0.36 mm and 0.76 mm being particularly common. The intermediate layer can also comprise multiple layers of thermoplastic material and, for example, be formed from multiple polymer films arranged flatly one above the other.

[0067] The composite pane preferably has an opaque masking area through which no vision is possible. This masking area is preferably arranged circumferentially in an edge region of the composite pane and surrounds a central transparent see-through area in a frame-like manner. This is particularly common for vehicle windows. However, this edge region does not have to coincide with the edge region used to describe the light trap. The masking area is preferably formed by an opaque masking print, which is particularly preferably applied at least to the interior-side surface of the outer pane.

[0068] The invention further encompasses a method for producing an illuminated glass element according to the invention. The glass pane is provided and provided with the at least one light-scattering structure, the light-scattering or diffractive layer of the light trap, the opaque element of the light trap, and the light source.

[0069] The individual steps can be performed in any order. The light source is often attached as a final step, especially if it is accessible via an exposed surface of the otherwise finished glass element.

[0070] If the glass element is a laminated pane, the glass pane is bonded to another pane via a thermoplastic interlayer. In this case, it is also possible for the light-diffusing structure and either the light-diffusing or diffractive layer or the opaque element to be applied not to the glass pane, but to the interlayer or to be inserted between the interlayer and the glass pane, as described above. The light source is preferably applied after the laminated pane.

[0071] Known lamination processes can be used, such as autoclave processes, vacuum bag processes, vacuum ring processes, calender processes, vacuum laminators, or combinations thereof. The bonding of the outer and inner panes is typically achieved using heat, vacuum, and / or pressure.

[0072] The invention further encompasses the use of a glass 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 glass 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 glass element can also be used as a component of furniture, electrical devices, as a component of furnishings, or as a furnishing.

[0073] 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.

[0074] They show:

[0075] Fig. 1 is a plan view of a first embodiment of the glass element according to the invention, Fig. 2 is a cross section along AA 1 through the glass element of Figure 1 ,

[0076] Fig. 3 is a plan view of a second embodiment of the glass element according to the invention,

[0077] Fig. 4 a cross section along BB 1 through the glass element from Figure 3,

[0078] Fig. 5 is a plan view of a third embodiment of the glass element according to the invention, Fig. 6 is a cross section along CC 1 through the glass element from Figure 5,

[0079] Fig. 7 is a schematic representation of the beam path within the glass pane of a glass element according to the invention,

[0080] Fig. 8 is a schematic representation of the beam path in the area of ​​the light trap of a glass element according to the invention,

[0081] Fig. 9 shows a cross section through a further embodiment of the inventive

[0082] glass element,

[0083] Fig. 10 shows a cross section through a further embodiment of the glass element according to the invention.

[0084] Figures 1 and 2 each show a detail of a first embodiment of the glass element according to the invention. The glass element is designed as a single glass pane and structurally consists of a single glass pane 2. The glass pane 2 is made of soda-lime glass and has a thickness of 2.1 mm, for example. The glass pane 2 is shown flat, but can be curved cylindrically or spherically depending on the intended use. The glass pane has two parallel main surfaces, namely a first surface III and a second surface IV, and a side edge surface e running between them. The side edge surface e is shown flat for the sake of simplicity, but in reality is often convexly rounded as a result of edge grinding.

[0085] The glass pane 2 is provided with four recesses 4, which extend as a feedthrough completely through the glass pane 2, i.e. from its first surface III to its second surface IV. These recesses 4 have, for example, a circular base area and are delimited by a circumferential edge surface i. The recesses 4 each have the overall shape of a circular cylinder, with the edge surface i forming the lateral surface and the base areas of the cylinder being defined by the inlet and outlet of the recess in the first surface III and second surface IV respectively. A light source 5 is inserted into each of the recesses 4 and is, for example, glued to the edge surface i. The light sources 5 are designed, for example, as light-emitting diodes (LEDs).During operation, they emit visible light, which is coupled into the glass pane 2 via the edge surface i and spreads there as a result of total internal reflection on its surfaces III, IV. Light-scattering structures 6 made of transparent enamel are also printed on the second surface IV of the inner pane 2. When the light from the light source 5 strikes these light-scattering structures 6, it is scattered and thus coupled out of the glass pane 2. The light-scattering structures 6 therefore appear to the observer as luminous surfaces, which can be used, for example, for illumination.

[0086] In addition to the radiation components that strike the light-scattering structures 6, conventional panes of this type also couple out those radiation components that strike the side edge surface e. Thus, the side edge surface e also emits unwanted radiation, which is undesirable and can be disruptive.

[0087] In order to reduce unwanted radiation via the side edge surface e, a completely circumferential light trap is formed in an edge region of the glass pane 2. The light trap is formed from a light-scattering or light-diffracting layer 7 on the first surface III and an opaque element 8 on the second surface IV. When the light reaches said edge region in the glass pane 2, it is scattered or diffracted by the light-scattering or light-diffracting layer 7, thereby interrupting total internal reflection. The light is at least partially deflected towards the opaque element 8, by which it is absorbed. The light therefore does not reach the side edge surface e or reaches it to a lesser extent, thereby preventing or at least reducing radiation via the side edge surface e.

[0088] The light-scattering or diffracting layer 7 and the opaque element 8 each extend in stripes and completely circumferentially along the outline of the glass pane 2, in particular parallel to the circumferential line. The strips are each delimited by two side edges, with one side edge facing the side edge surface e of the glass pane 2 and the other side edge facing away from the side edge surface e. The light-scattering or diffracting layer 7 has, for example, a width (strip width, distance between the said side edges) of 30 mm. The side edge facing the side edge surface e has a distance of, for example, 10 mm from the side edge surface e. Accordingly, the side edge facing away from the side edge surface e has a distance of, for example, 40 mm from the side edge surface e. The light-scattering or diffracting layer 7 is therefore spaced apart from the side edge surface e overall.The opaque element 8 has, for example, a width (strip width, distance between the said side edges) of 30 mm. The opaque element directly borders the side edge surface e. The side edge facing the side edge surface e is therefore at a distance of 0 mm from the side edge surface e. Accordingly, the side edge facing away from the side edge surface e is at a distance of, for example, 30 mm from the side edge surface e.

[0089] The light-scattering or diffracting structure 7 can be formed, for example, as an optical grating or a microprism film and can be adhered to the first surface III. Alternatively, the light-scattering or diffracting structure 7 can be formed as a scattering print on the first surface III, similar to the light-scattering structures 6 for light extraction. The opaque element 8 can, for example, be an opaque print on the second surface IV or an adhered opaque component made of rubber or plastic.

[0090] Figure 1 shows a plan view of the first surface III of the glass pane 2. The light-scattering structures 6 and the edge region of the opaque element 8 can be seen when viewed through the transparent glass pane 2.

[0091] Figures 3 and 4 each show a detail of a second embodiment of the glass element according to the invention. The glass element essentially corresponds to that of Figures 1 and 2, with the single glass pane 2, the light-scattering structures 6, and the light trap consisting of the light-scattering or diffractive layer 7 and the opaque element 8, which are configured in the same way as in the first embodiment. The second embodiment differs from the first embodiment in the type of light coupling and the geometric arrangement of the light trap.

[0092] Three light sources 3 are attached, for example glued, to the side edge surface e of the glass pane 2 and couple light via the side edge surface e, which then propagates in the glass pane 2 as a result of total internal reflection at the surfaces III, IV. The light sources 5 are also designed here, for example, as light-emitting diodes (LEDs). Those sections of the edge region of the glass pane 2 that border the sections of the side edge surface e with the light sources 5 are not provided with the light trap. The light-scattering or diffracting layer 7 and the opaque element 8 are arranged completely circumferentially in the edge region, but are interrupted at the points where the light is coupled in. The light coupling is therefore not disrupted by the light trap, which would prevent total internal reflection.If the light reaches the side edge surface e after passing through the glass pane 2, the undesired radiation via the side edge surface e is prevented or at least reduced by the light trap.

[0093] Figure 3 again shows a plan view of the first surface III of the glass pane 2. The light-scattering structures 6 and the edge area of ​​the opaque element 8 can be seen through the transparent glass pane 2. The section line BB 1 runs through an interruption of the light trap, so that the light-scattering or diffracting layer 7 and the opaque element 8 can be seen behind the cutting plane in Figure 4 and are therefore not shown hatched.

[0094] Figures 5 and 6 each show a detail of a third embodiment of the glass element according to the invention. The glass element essentially corresponds to that of Figures 1 and 2, with the single glass pane 2, the light-scattering structures 6, and the light trap consisting of the light-scattering or diffracting layer 7 and the opaque element 8, which are designed in the same way as in the first embodiment. The second embodiment differs from the first embodiment in the type of light coupling.

[0095] Four light sources 5 are attached, for example, glued, to the second surface IV of the glass pane 2. Opposite each light source 5, a light coupling means 11, which is designed, for example, as a microprism film, is attached to the first surface III. The light coupling means 11 are irradiated through the glass pane 2 by the light sources 5. The light then re-enters the glass pane 2 via the first surface III at a changed beam angle and spreads out through it by total internal reflection. The light is thus coupled into the glass pane 2 via the first surface III by means of the light coupling means 11. The light radiation is indicated by arrows in the figure.

[0096] To reduce unwanted radiation across the side edge surface e, a completely circumferential light trap is formed in an edge region of the glass pane 2. The light trap is formed completely circumferentially in the edge region of the glass pane 2 to reduce the radiation of light across the side edge surface e. The light-scattering or diffractive layer 7 and the opaque element 8 are not interrupted along any length of the edge region.

[0097] Figure 5 again shows a plan view of the first surface III of the glass pane 2. The light-scattering structures 6 and the edge region of the opaque element 8 can be seen when viewed through the transparent glass pane 2.

[0098] Figure 7 illustrates the propagation of light from light source 5 in glass pane 2. The light strikes surfaces III, IV from the interior of glass pane 2, which represent interfaces between an optically denser and an optically less dense medium. Therefore, a critical angle OCT of total reflection exists, which is determined from the refractive index ni of glass pane 2 and the refractive index n2 of the surrounding air, as a T = arcsin(— ). The critical angle OCT at a wavelength of 589 nm ni is, for example, 41° for a transition from soda-lime glass (ni = 1.52) to air (ni = 1.0).

[0099] Portions of the light coupled into the glass pane 2 strike the surfaces III, IV of the glass pane 2 at an angle of incidence a, which is greater than the critical angle OCT. These light rays are totally reflected at an angle of reflection a 1, which is equal in magnitude to the angle of incidence α. The reflection at the first surface III is shown. The incident and the emerging light beam are indicated by arrows. The emerging light beam passes through the glass pane 2 again to the second surface IV, which it strikes again at the angle of incidence α, so that it is again totally reflected. In this way, the propagation of the light in the glass pane 2 would continue until the light either strikes the light-scattering structures 6 and is coupled out via the surfaces III, IV (which is desired) or reaches the side edge surface e and is emitted via the side edge surface e (which is not desired).

[0100] The angle of incidence a and the angle of reflection a 1 are related to the surface normal of the reflecting surface, as is generally the case.

[0101] Figure 8 illustrates the effect of the beam trap according to the invention to reduce unwanted radiation via the side edge surface e. In the edge region of the glass pane 2, the light strikes the light-scattering or diffractive layer 7. This prevents total internal reflection. At least parts of the light are reflected back into the glass pane 2 by the light-scattering or diffractive layer 7 at an angle of reflection ß that is significantly smaller than the angle of incidence α. The light beam is thereby deflected towards the opaque element 8, by which it is absorbed. The light trap thus at least partially intercepts the light before it reaches the side edge surface e. The radiation via the side edge e is consequently at least reduced.

[0102] The width and relative arrangement of the light-scattering or diffracting layer 7 and the opaque element 8 can be selected for the specific application such that the largest possible proportion of the light is intercepted, which would reach the side edge e without the light trap. They depend, among other things, on the thickness of the glass pane 2, the wavelength of the light, and the material of the glass pane 2 and its surroundings (the wavelength and material determine the refractive indices and thus the critical angle OCT), and the design of the light-scattering or diffracting layer 7 (which affects the angle of reflection ß).

[0103] Figure 9 illustrates a further development of the glass element according to the invention. It shows a cross-section through a section of a glass pane 2, on whose side edge surface e a light source 5 is mounted. A central aperture 10 is arranged between the light source 5 and the side edge surface e. The central aperture 10 prevents the light from irradiating a central section of the side edge surface e, so that the light is coupled in only via sections of the side edge surface e that directly border surfaces III, IV and between which the central section is arranged.

[0104] Light source 5 illuminates the side edge surface e according to its beam cone over a certain angular range. Regarding the coupling, a distinction can be made between three angle groups.

[0105] In a first angle group, the light strikes surfaces III, IV near the side edge surface e at a small angle of incidence α (indicated in the figure by the thin solid arrows). The angle of incidence α is smaller than the critical angle OCT of total internal reflection. These radiation components are not totally reflected, but are largely refracted at the respective surface and leave the glass pane 2 mostly via the respective surface. Radiation that is reflected to a small extent strikes the opposite surface, where it is again largely refracted. The light from the first angle group is therefore lost for the intended light coupling. Radiation via surfaces III, IV near the light source 5 can optionally be prevented, for example, by opaque prints that absorb the radiation from the first angle group.

[0106] In a second angle group, the light (at a greater distance from the side edge surface e than the light in the first angle group) strikes surfaces III, IV at a larger angle of incidence α (indicated in the figure by the thick solid arrows). The angle of incidence α is greater than the critical angle OCT of total internal reflection. The light propagates within the glass pane 2 as described above (see Figure 7) and serves to illuminate the light-scattering structures 6 as intended.

[0107] In a third angle group, the light would be coupled into the glass pane 2 even more flatly than in the second angle group. The light of the third angle group would

[0108] - either pass between the surfaces III, IV through the glass pane 2 and strike the side edge surface e opposite the light source 5, without striking one of the surfaces III, IV and being totally reflected thereon (indicated in the figure by the dashed arrow),

[0109] - or strike the surfaces III, IV of the glass pane 2 with such a large angle of incidence that it is only totally reflected a few times, the reflection points being so far apart from each other that there is no reflection point in the area of ​​the light-scattering or -diffracting layer 7, so that the light-scattering or -diffracting layer 7 is, as it were, skipped.

[0110] In both cases, the light trap according to the invention cannot act on the radiation of the third angle group and cannot prevent the radiation via the side edge surface e.

[0111] The central aperture 10 blocks the light from the third angle group and prevents it from being coupled into the glass pane 2. This allows the radiation via the side edge e to be further reduced. The dimensions of the central aperture 10 are ideally selected depending on the specific application in such a way that, on the one hand, the light from the third angle group is blocked as completely as possible, and, on the other hand, the light from the second angle group is not blocked or is only blocked to a minimal extent. The principle of the central aperture 10 has been explained here using the example of a design in which the light is coupled into the glass pane 2 via the side edge surface e (as in Figures 3 and 4). However, the central aperture 10 can also be used if the light is coupled via the edge surface i of a recess 4 (as in Figures 1 and 2).

[0112] In all embodiments, the prevention of the emission of light from the first angle group can be achieved by an opaque cover print, an opaque sticker, or similar opaque elements near the locations where the light is coupled in, regardless of whether the light is emitted via the side edge surface e, the edge surface i of a recess, or by a light coupling means 11 on one of the surfaces III, IV. The opaque element is arranged in the area of ​​the surface(s) of the glass pane that is irradiated by the light from the first angle group.

[0113] Figure 10 shows a cross-section through a further embodiment of the glass element according to the invention. The glass element is designed as a composite pane. It comprises the glass pane 2, which is basically designed as in Figures 1 and 2, with the light source 5 in the recess 4, the light-scattering structures 6 on the second surface IV, and the light trap, which is formed from the light-scattering or diffractive layer 7 and the opaque element 8 circumferentially in the edge region.

[0114] The glass pane 2 is connected to another pane 1 via a thermoplastic intermediate layer 3. The other pane 1 is also a pane of soda-lime glass with a thickness of, for example, 2.1 mm.

[0115] The composite pane is intended as a vehicle roof pane. For the sake of simplicity, it is shown flat, although vehicle roof panes are typically curved. The glass pane 2 is the inner pane of the composite pane, which in the installed position faces the vehicle interior. Its first surface III is its outer surface, which in the installed position faces the further pane 1 and the outside environment. Its second surface IV is its inside-side surface, which in the installed position faces the vehicle interior. The further pane 1 is the outer pane of the composite pane, which in the installed position faces the outside environment. It also has a first or outside surface I, which in the installed position faces the outside environment, and a second or inside-side surface II, which in the installed position faces the glass pane 2 and the vehicle interior.The interior-side surface II of the additional pane 1 (outer pane) and the exterior-side surface III of the glass pane 2 (inner pane) face each other and are connected to each other via the thermoplastic intermediate layer 3. The intermediate layer 3 is formed from a single PVB-based film with a thickness of, for example, 0.76 mm. The additional pane 1 and the intermediate layer 3 are, for example, tinted, while the glass pane 2 is made of clear glass. As a result of this tinting, the total transmittance through the composite pane is, for example, less than 15%. The interior-side surface II of the additional pane 1 is provided with a masking print 9 in a circumferential edge region, which forms an opaque masking region of the composite pane, as is common with vehicle windows. The recess 4 with the light source 5 is arranged in this masking region, which advantageously makes them unobtrusive.The same applies to the light trap consisting of light-scattering or diffracting layer 7 and opaque element 8.

[0116] List of reference symbols:

[0117] (1) additional disc

[0118] (2) Glass pane

[0119] (3) thermoplastic intermediate layer

[0120] (4) Recess of the glass pane 2

[0121] (5) Light source

[0122] (6) light-scattering structure

[0123] (7) light-scattering or diffractive layer

[0124] (8) opaque element

[0125] (9) Cover printing

[0126] (10) Central panel

[0127] (11) Light coupling means

[0128] (I) first / outer surface of the further pane 1

[0129] (II) second / interior surface of the further pane 1

[0130] (III) first surface of the glass pane 2

[0131] (IV) second surface of the glass pane 2

[0132] (e) Side edge surface of the glass pane 2

[0133] (i) Edge surface of the recess 4

[0134] OCT Critical angle of total reflection a Angle of incidence of light a 1 Angle of reflection of light during total reflection (a = a 1 ) ß Angle of reflection of the light emanating from the light-scattering diffraction layer 7

[0135] A - A 1 Cutting line

[0136] B-B 1 Cutting line

[0137] C-C 1 Cutting line

Claims

Patent claims Illuminated glass element comprising a glass pane (2) with a first surface (III), a second surface (IV) and an intermediate one side edge surface (e) which - is equipped with at least one light source (5) suitable for coupling light into the glass pane (2) in such a way that the light propagates in the glass pane (2), in particular by total internal reflection at the first surface (III) and the second surface (IV), and - is provided with at least one light-scattering structure (6) suitable for coupling said light out of the glass pane (2) via the first surface (III) and / or via the second surface (IV), characterized in that the glass pane (2) is provided at least section by section in a circumferential edge region with a light trap suitable for reducing the emission of light via the side edge surface (e), wherein the light trap is formed from a light-scattering or -diffracting layer (7) on the first surface (III) and an opaque element (8) on the second surface (IV). Illuminated glass element according to claim 1, wherein the light-scattering or diffracting layer (7) is suitable for deflecting the incident light in the direction of the opaque element (8). Illuminated glass element according to claim 1 or 2, wherein the light-scattering or diffracting layer (7) is configured as an optical grating, a printed layer, a microprism film, or a structured coating. Illuminated glass element according to any one of claims 1 to 3, wherein the light-scattering or diffracting layer (7) extends in the form of a strip along at least one section of the side edge surface (e) with a width of 10 mm to 65 mm, preferably 30 mm to 50 mm. Illuminated glass element according to claim 4, wherein the light-scattering or diffracting layer (7) has a distance from the side edge surface (e) of 0 mm to 35 mm, preferably 5 mm to 20 mm. An illuminated glass element according to any one of claims 1 to 5, wherein the opaque element (8) is designed as a printed element or as an opaque component made of rubber or plastic. An illuminated glass element according to any one of claims 1 to 6, wherein the opaque element (8) extends in the form of a strip along at least one section of the side edge surface (e) with a width of 10 mm to 100 mm, preferably 20 mm to 70 mm. An illuminated glass element according to claim 7, wherein the light-scattering or light-diffusing layer (7) is directly adjacent to the side edge surface (e). Illuminated glass element according to one of claims 1 to 8, wherein the glass pane (2) has a recess (4) which is bounded by a circumferential edge surface (i), and wherein the light source (5) is arranged in or on the recess (4) such that it is suitable to couple light into the glass pane (2) via the edge surface (i), and wherein the light trap is formed completely circumferentially in the edge region.An illuminated glass element according to any one of claims 1 to 8, wherein the light source (5) is arranged on one of the surfaces (III, IV) and a light coupling means (11) is arranged opposite it on the other surface (III, IV), which is suitable for coupling the light incident on the light coupling means (11) through the glass pane (2) into the glass pane (2), and wherein the light trap is formed completely around the edge region (R). An illuminated glass element according to any one of claims 1 to 8, wherein the at least one light source (5) is arranged on the side edge surface (e) such that it is suitable for coupling light into the glass pane (2) via the side edge surface (e), and wherein the light trap is formed completely around the edge region (R) and is interrupted only at the point(s) where the light is coupled into the glass pane (2).Illuminated glass element according to claim 9 or 11, wherein a central aperture is arranged between the light source (5) and the edge surface (i) or the side edge surface (e).

13. Illuminated glass element according to any one of claims 1 to 12, wherein the light source (5) is a light-emitting diode.

14. Illuminated glass element according to any one of claims 1 to 13, comprising a further Disc (1) which is connected to the glass disc (2) via a thermoplastic intermediate layer (3).

15. Use of an illuminated glass element according to any one of claims 1 to 14 as a window pane of a vehicle, a building or an interior, as a component of furniture, electrical appliances, as a component of furnishings or as a furnishing, preferably as a vehicle roof pane.

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