Lighting plate-type glass element with reduced light emission via sides

Abstract

The invention relates to an illuminating glass element comprising a glass sheet (2) having a first surface (III), a second surface (IV) and a side surface (e) extending therebetween, said glass sheet (2) being:-equipped with at least one light source (5) adapted to couple light into said glass sheet (2), the invention relates to a glass pane (2) having a first surface (III) and a second surface (IV) such that light propagates in the glass pane (2), in particular by total reflection at the first surface (III) and at the second surface (IV), and having at least one light scattering structure (6) suitable for coupling the light out of the glass pane (2) via the first surface (III) and / or via the second surface (IV), characterized in that the light scattering structure (6) is arranged in the glass pane (2). According to the invention, the glass pane (2) is equipped in the peripheral edge region at least in sections with light traps which are suitable for reducing the emission of light via the side surface (e), said light traps being formed by a light scattering or light diffractive layer (7) on the first surface (III) and an opaque element (8) on the second surface (IV).

Description

Technical Field

[0001] The invention relates to a lighting glazing element having at least one glass pane and to the use thereof. Background Art

[0002] Illuminated glass panes are known per se. For illumination, light sources, usually light-emitting diodes, can be arranged in the side faces or recesses of the glass pane so that light can be coupled into the glass pane via the side faces or the edge faces of the recess and propagate there due to total reflection. The light can be coupled out of the glass pane again via light-scattering structures, thus achieving illumination. The shape of the light-scattering structures can be freely selected so that any shape of illuminated areas can be generated, for example as a pattern. Illuminated glass panes of this type are known, for example, from WO 2014 / 060409 A1 or WO 2014 / 167291 A1.

[0003] In the field of vehicles, such illuminated glass panels are of particular interest as roof panels, with the aid of which the interior can be illuminated. Illuminated glass panels are usually the inner panels of a composite panel. However, such illuminated glass panels can also be used for other vehicle panels, or even panels in the field of buildings and construction or in fixtures. In addition to illuminating the interior, the illuminated area formed by the light-scattering structure can also be used to display information, for example for displaying direction arrows, status indicators, warnings, price lists, etc., or to generate aesthetic patterns.

[0004] With conventional illuminated glass panes of this type, there is the problem that part of the light propagates all the way to the peripheral side edges of the glass pane and is coupled out there. As a result, not only the light-scattering structure is illuminated, but also the side edges. On the one hand, this is disruptive, since the light emission via the side edges is undesirable and annoying for the observer and can even lead to the fact that the glass panes no longer meet legal requirements, especially in the field of vehicle panes, where glare for drivers or other road users must be excluded. On the other hand, the light outcoupling at the side edges can also lead to light losses, which are then no longer available for the actually intended outcoupling at the light-scattering structure. As a result, the lighting intensity or efficiency is reduced.

[0005] Unpublished international patent application PCT / EP2023 / 051960 proposes to provide a reflective layer to the side face, which reflects light back to the glass sheet and thereby prevents light from being emitted via the side face. The reflective layer is in turn covered with an opaque material, which is used both for shielding and for mechanically and chemically protecting the light-reflecting layer.

[0006] There is still a need for an illuminated glazing of the type mentioned in the introduction, in which undesired light emissions via the side edge faces are prevented or at least reduced. It is an object of the present invention to provide an illuminated glazing element having such an improved illuminated glazing. Summary of the invention

[0007] The object of the invention is achieved by a lighting glazing element according to claim 1. Preferred embodiments emerge evidently from the dependent claims.

[0008] In the context of the present invention, a lighting glass element is a plate-type or sheet-type object, which includes at least one glass plate and is particularly formed by at least one glass plate in structure. A glass element can be a single glass plate, and therefore is only composed of the glass plate in structure. Alternatively, a glass element can be a composite plate or an insulating glass, which contains the glass plate. In the case of a composite plate, a glass plate is connected to another plate via a thermoplastic interlayer. In the case of an insulating glass, a glass plate is connected to another plate via a surrounding spacer in an edge region, forming an inter-plate space that is usually filled with an inert gas or evacuated. Glass elements can be used as window panels, for example, as window panels for vehicles, buildings or interiors. However, glass elements can also be used as components of furniture or electrical appliances, for example, as door panels for storage cabinets or shelves or as oven door panels. Glass elements can also be used as fixtures, for example, as display panels for bars or discotheques.

[0009] The lighting glazing element according to the invention comprises at least one glass pane having a first surface (main surface) and a second surface (main surface) which are usually embodied substantially parallel to each other and side surfaces extending between the first surface and the second surface.

[0010] The glass element or glass pane can be flat or curved in one or more spatial directions. In the latter case, usually one of the surfaces is concavely curved and the other surface is convexly curved. The side faces can be flat. However, usually the side faces are ground to minimize the risk of injury caused thereby. The side faces are then bent or rounded, in particular convexly curved or rounded.

[0011] The glass pane is provided with at least one light source, which is suitable for coupling light emitted by the light source into the glass pane, so that the light propagates in the glass pane between a first surface and a second surface, in particular by total reflection at the first surface and the second surface. As is common in general lighting glass panes, the glass pane is provided with at least one light scattering structure, which is suitable for coupling the 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 surface or the second surface or in contact with one of these surfaces. When the light propagating in the glass pane impinges on the light scattering structure, the light is scattered, thereby preventing total reflection, so that the scattered light is coupled out of the glass pane and leaves the glass pane.

[0012] According to the invention, the glass sheet is provided at least section by section in the peripheral edge region with a light trap, which is suitable for at least reducing or even completely preventing light emission via the side face of the glass sheet. In other words, at least one section of the peripheral edge region of the sheet is provided with a light trap. The light trap is formed by a light scattering or light diffraction layer on a first surface of the glass sheet and an opaque element on a second surface of the glass sheet. The light scattering or light diffraction layer and the opaque element can be applied directly to the respective surface or in contact therewith.

[0013] In conventional illuminated glazings, part of the light propagating in the glazing strikes the side face and is then coupled out of the glazing via the side face. As a result, light is also emitted via the side face, which is undesirable. In the glazing element according to the invention, this is prevented or at least reduced by a light trap arranged in the edge region. When the light strikes a light-scattering or light-diffraction layer on the first surface of the glazing, the light-scattering or light-diffraction layer interrupts total reflection. The light scattered or diffracted at the layer strikes the opaque element and is absorbed by it. As a result, the light trap intercepts the light, so to speak, before it reaches the side face of the glazing. At least part of the light that would strike the side face and would be coupled out via the side face in the absence of the light trap is prevented from doing so by the light trap and is, so to speak, swallowed up. This prevents emission via the side face. With a suitable design of the glazing element, it is even possible to intercept all the light before it strikes the side face and to prevent emission completely. This is a great advantage of the invention.

[0014] If the glass element according to the invention is a window panel (e.g. of a vehicle, a building, an interior, a piece of furniture or a fixture), the glass element is intended to be inserted into a window opening and there to separate the interior from the external surroundings. The glass sheet then has an outer side surface and an inner side surface. In the context of the present invention, "outer side surface" refers to that main surface which is intended to face the external surroundings in the installed position. In the context of the present invention, "inner side surface" refers to that main surface which is intended to face the interior in the installed position. The first surface of the glass sheet (in the context of the present invention, the surface of the light scattering or light diffraction layer with the light trap) can be the outer side surface of the glass sheet, and the second surface (in the context of the present invention, the surface of the opaque element with the light trap) is then the inner side surface. However, alternatively, the first surface of the glass sheet can also be the inner side surface; while the second surface is the outer side surface.

[0015] The glass pane is equipped with a light source, which is suitable for coupling light into the glass pane. The light can be coupled in, in particular, via a side edge of the glass pane, via an edge of a groove in the glass pane or via one of the surfaces of the glass pane by means of a light coupling device. The light is radiated into the glass pane and impinges on one of the surfaces of the glass pane, which is an interface with an adjacent medium. The glass pane generally has a higher refractive index (e.g. soda-lime glass: 1.52 at a light wavelength of 589 nm) than the adjacent medium (e.g. the surrounding atmosphere, in particular air: 1.00 at a light wavelength of 589 nm). Since there is therefore a transition from a medium with a greater optical density to a medium with a lower optical density, the critical angle α for total reflection T can be determined as

[0016]

[0017] where n1 is the refractive index of the glass sheet and n2 is the refractive index of the surrounding environment. For example, at the transition from soda-lime glass to air and a wavelength of 589 nm, the critical angle for total reflection is α T =41°.

[0018] Light is usually radiated into the glass sheet by a light source over a specific angle range. The light can strike the surface of the glass sheet from the inside of the glass sheet. The light strikes the surface of the glass sheet at an angle of incidence that depends on the angle into which the light has been radiated. Two situations can be distinguished:

[0019] If the angle of incidence is less than the critical angle for total reflection, the light is refracted at the surface and a large part of said light enters the surroundings of the glass sheet. This situation occurs in particular in the vicinity of the coupling point. Only a small part is reflected at the surface at a reflection angle corresponding to the angle of incidence and then strikes the opposite surface, where a large part of the remaining light intensity is refracted again and leaves the glass sheet. This light is therefore lost for its intended use, i.e. illuminating the glass sheet by coupling out at the light-scattering structure. Undesired emissions in the vicinity of the coupling point can optionally be prevented by an opaque element, for example a shielding print or sticker.

[0020] If the angle of incidence is greater than the critical angle for total reflection, the light is completely reflected at the surface at a reflection angle corresponding to the angle of incidence. The light does not enter the surroundings and propagates in the glass sheet essentially without loss due to repeated total reflections, being reflected back and forth, as it were, between the two surfaces of the glass sheet. Those parts of the light that impinge on the light-scattering structures are coupled out, which is the basis for the intended illumination of the glass sheet. The parts of the light that are not coupled out at the light-scattering structures reach the edge region of the glass sheet, where they are coupled out via the side faces or intercepted by the light trap according to the invention.

[0021] As is common in ray optics, the "angle of incidence" refers to the angle of a ray of light incident on a surface relative to the surface normal to the surface at the point of incidence. The angle of reflection is similarly determined relative to the surface normal, as is the critical angle for total reflection.

[0022] The glass sheet can be conceptually divided into a surrounding edge region adjacent to the peripheral side face and a central region surrounded by the edge region. The light scattering structure is arranged in the central region; while the light trap according to the invention is arranged in the edge region. The edge region is arranged in a strip-like manner along the side face or contour of the glass sheet; the edge region can also be called an edge strip. That dimension of the edge strip extending along the side face (or parallel to the side face) can be called the length of the edge region, and the dimension extending perpendicular to the side can be called the width of the edge region. The width of the edge region corresponds to the extent to which the edge region emanating from the side face extends towards the central region. The edge region has, for example, a width of 10 cm or even only 7 cm or 5 cm.

[0023] The light trap according to the present invention is arranged in the edge region of the glass plate. However, the light trap does not have to completely cover the edge region. The components of the light trap (light scattering / light diffraction 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 at least over a longitudinal section of the edge region. Therefore, there is at least one longitudinal section of the edge region, along which the light scattering / light diffraction layer and the opaque element are present, wherein the light scattering / light diffraction layer and the opaque element extend independently of each other over a portion of the width of the edge region (transverse section) or over the entire width of the edge region. The light scattering / light diffraction layer and the opaque element can be directly adjacent to the side surface or spaced apart from it independently of each other.

[0024] The light scattering or light diffraction layer and the opaque element are arranged in the same longitudinal section of the edge region. However, the light scattering or light diffraction layer and the opaque element do not need to cover the same transverse section. In other words, when looking through the glass sheet, the light scattering or light diffraction layer and the opaque element do not need to be arranged overlapping each other, but can be offset from each other (relative to the width dimension of the glass sheet).

[0025] It is particularly advantageous if the light trap is implemented completely around the edge region and is interrupted only at any point for light coupling. The emission is then reduced over the entire side edge. However, it is also conceivable that only one section or several sections of the edge region are equipped with a light trap, while other sections remain free. This can be selected, for example, when the emission via only a portion of the side edge must be reduced.

[0026] The light scattering or light diffraction layer is particularly suitable for deflecting the light incident thereon in the direction of the opaque element. The light deflected at the light scattering or light diffraction layer is (at least partially) reflected into the glass sheet at a reflection angle less than the angle of incidence, and therefore does not shine on the side surface of the glass sheet, but shines on the opaque element and is absorbed by it. For this reason, the light scattering or light diffraction layer and the opaque element are appropriately positioned relative to each other. The width and relative arrangement of the light scattering / light diffraction layer and the opaque element depend on the design of the glass element in a specific application. They depend in particular on the thickness of the glass sheet, the wavelength of the light, the material and the surrounding environment of the glass sheet, and the design and refractive index of the light scattering or light diffraction layer.

[0027] The light scattering or light diffraction layer is formed in a strip-like manner and extends along (a section of) the side of the first surface, in particular parallel to the side. In other words, the light scattering or light diffraction layer extends in a strip-like manner along at least one section of the side surface of the glass plate. Similar to the edge area, the dimension along which the light scattering or light diffraction layer extends can be referred to as the length of the light scattering or light diffraction layer, and the dimension extending perpendicular to the side can be referred to as the width. The width of the light scattering or light diffraction layer is preferably constant. As such, the strip-shaped light scattering or light diffraction layer has two sides extending along the length dimension and defining the width dimension. One of these side surfaces faces the side of the first surface, while the other side edge faces away from the side of the first surface.

[0028] The width of the light scattering or light diffraction layer is preferably 10mm to 65mm, particularly preferably 30mm to 50mm. The side of the light scattering or light diffraction layer facing the first surface preferably has a distance of 0mm to 35mm, particularly preferably 5mm to 20mm or 10mm to 20mm from the side of the first surface. This distance can also be referred to as the distance between the light scattering or light diffraction layer and the side surface. At a distance of 0mm, the light scattering or light diffraction layer is directly adjacent to the side of the first surface. At a distance greater than 0mm, the light scattering or light diffraction layer is spaced apart from the side of the first surface, so that there is an area of ​​the first surface that is not occupied by the light scattering or light diffraction layer between the light scattering or light diffraction layer and the side of the glass plate. The side of the light scattering or light diffraction layer facing away from the side of the first surface preferably has a distance of 10mm to 100mm, particularly preferably 35mm to 70mm from the side of the first surface.

[0029] The light scattering or light diffraction layer is in direct contact with the first surface of the glass sheet in order to exert its effect. The light scattering or light diffraction layer can be applied directly to the first surface. If the glass element is a composite panel, in which the first surface of the glass sheet faces the interlayer, the light scattering or light diffraction layer can also be applied to the surface of the thermoplastic interlayer facing the first surface of the glass sheet and in contact with it. Alternatively, the light scattering or light diffraction layer can be inserted between the first surface of the glass sheet and the interlayer.

[0030] In one embodiment of the present invention, the light scattering or light diffraction layer is implemented as a grating. The grating is a periodic structure (diffraction grating) for diffracting light. The grating has a parallel linear structure, through which a plurality of slits are formed. The grating works by diffraction of light: the light of each slit interferes and forms an interference pattern. This causes the light to be deflected, wherein the magnitude of the deflection depends 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 linear structures. Taking into account the wavelength of the light source, the grating constant and the geometric arrangement of the grating and the opaque element are appropriately matched to each other so that the maximum possible proportion of the light diffracted at the grating is illuminated on the opaque element. The grating is particularly a reflection grating. In a reflection grating, the diffraction effect is generated by reflection from a properly prepared reflective layer. For example, the linear structure can be introduced into a suitable (reflective) substrate by etching, scribing or by exposure. The grating is preferably provided as a finished component and attached to the first surface. The grating is commercially available and can be purchased. The grating can be bonded to the first surface, for example. In the case of a composite pane, in which the first surface of the glass pane faces the intermediate layer, the grating can be inserted between the first surface of the glass pane and the thermoplastic layer. Alternatively, however, it is also possible to provide the first surface with a suitable (reflective) coating and to form the grating therein. The coating can, for example, be a dielectric layer sequence or a layer sequence with metal-containing layers; the grating can, for example, be formed by laser patterning of the coating.

[0031] In another embodiment of the invention, the light scattering or light diffraction layer is implemented as an imprint. The imprint can be printed directly onto the first surface of the glass sheet. In the case of a composite panel, in which the first surface of the glass sheet faces the intermediate layer, the imprint can alternatively be printed onto the surface of the thermoplastic layer facing the first surface of the glass sheet and in contact with it.

[0032] The imprint acts in particular as a light-scattering structure. This can be achieved in any manner, for example by means of a light-scattering additive in the printing paste. Suitable light-scattering additives are, for example, glass frits, which can optionally be baked into the first surface of the glass sheet. Glass beads or other particles in the micrometer range can also be used as light-scattering additives.

[0033] The color of the print is unimportant. Therefore, any pigment or dye may optionally be added to the printing paste.

[0034] In another embodiment of the present invention, the light scattering or light diffraction layer is implemented as a microprismatic film. The microprismatic film comprises a substrate (particularly a flexible substrate, for example in the form of a plastic film) having a flat arrangement of a plurality of prisms having a size in the micrometer range. The microprisms act in particular as reflective prisms and reflect light that shines on the reflective prisms at a reflection angle that deviates from the angle of incidence, in particular less than the angle of incidence, so that the light is deflected onto the opaque element. Due to the size in the micrometer range, diffraction and refraction also occur on the prisms, so that the microprismatic film can be regarded as a light scattering or light diffraction layer. The microprismatic film is preferably provided as a finished component and attached to the first surface. The microprismatic film is commercially available and can be purchased. The microprismatic film can be bonded to the first surface, for example, adhesively. In the case of a composite plate, in which the first surface of the glass plate faces the interlayer, the microprismatic film can be inserted between the first surface of the glass plate and the thermoplastic layer.

[0035] The side length of the individual microprisms is preferably 10 μm to 250 μm, particularly preferably 20 μm to 100 μm, for example about 30 μm, 50 μm or 70 μm. In a particularly advantageous embodiment, the microprismatic 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 microprismatic film facing away from the glass plate to enhance the reflection effect. Instead of a flexible microprismatic film, a rigid plastic sheet with a flat arrangement of microprisms can also be used.

[0036] In another embodiment of the present invention, the light scattering or light diffraction layer is implemented as a structured coating. The structured coating is preferably a microperforated dielectric film coating. A SiO2 coating is particularly preferred. The coating preferably has a layer thickness of less than 1 μm, particularly preferably 50 nm to 500 nm. "Microperforation" refers to a coating interruption (especially periodic) with a size in the nanometer or micrometer range, which is introduced into the coating, for example, by laser processing. The light scattering or light diffraction effect of such a coating is particularly based on local differences in refractive index. The coating can be applied directly on the first surface of the glass plate, for example, by chemical or physical vapor deposition. In the case of a composite plate, where the first surface of the glass plate faces the intermediate layer, the coating can alternatively be applied to the surface of the thermoplastic intermediate layer facing the glass plate and in contact with it. Alternatively, the coating can be provided on a carrier film, such as a PET film, in a prefabricated manner and inserted between the first surface of the glass plate and the intermediate layer.

[0037] The opaque element is particularly suitable for (at least partially) absorbing light deflected at the light scattering or light diffraction layer. The opaque element is strip-shaped and extends along the side (area) of the second surface, in particular parallel to the side. In other words, the opaque element extends along at least one section of the side surface of the glass sheet in a strip-shaped manner. Similar to the edge area and the light scattering or light diffraction layer, the dimension of the opaque element extending along the side can be referred to as the length of the opaque element, and the dimension extending perpendicular to the side can be referred to as the width. The width of the opaque element is preferably constant. For its part, the strip-shaped opaque element has two sides extending along the longitudinal dimension and defining the width dimension. One of these sides faces the side of the second surface, and the other side faces away from the side of the second surface.

[0038] The opaque element is preferably arranged at least in the same longitudinal section of the edge region as the light scattering or light diffraction layer. This means that the opaque element has at least the same length as the light scattering or light diffraction layer and is arranged so that the opaque element completely overlaps the light scattering or light diffraction layer. The opaque element can have the same length as the light scattering or light diffraction layer and can be arranged in the same longitudinal section of the edge region, wherein the opaque element and the light scattering or light diffraction layer extend completely along the longitudinal section. However, the opaque element can also extend beyond the light scattering or light diffraction layer on one or both sides with respect to the longitudinal dimension. In both cases, the light deflected at the light scattering or light diffraction layer can be effectively absorbed by the opaque element.

[0039] The side edge of the side facing the second surface of the opaque element is particularly preferably at a distance of 0 mm from the side of the second surface, i.e., preferably directly adjacent to the side or side face of the second surface. However, the opaque element may also be spaced apart from the side of the second surface, preferably at a distance of up to 20 mm, so that the side of the side facing the second surface of the opaque element is preferably at a distance of 0 mm to 20 mm from the side of the second surface. This distance may also be referred to as the distance between the opaque element and the side face. The required width of the opaque element depends in particular on the light deflection effect of the light scattering or light diffraction layer. Usually, the side of the side facing the second surface of the opaque element and the side of the second surface may have a distance less than the distance between the side of the side facing the first surface of the light scattering or light diffraction layer and the side of the first surface. In this case, compared with the light scattering or light diffraction layer, the opaque element does not extend too far toward the central area of ​​the glass plate, which is usually sufficient to deflect the light at the light scattering or light diffraction layer at a reflection angle toward the side face, and the reflection angle is less than the incident angle, but still greater than zero. However, the opaque element can extend towards the central area as far as the light scattering layer or even farther than the light scattering layer, so that the side of the opaque element facing away from the second surface has a distance from the side of the second surface that is equal to or even greater than the distance between the side of the light scattering or light diffraction layer facing away from the first surface and the side of the first surface.

[0040] In a typical application, the side edge of the opaque element facing away from the side edge of the second surface is 20 mm to 100 mm away from the side edge of the second surface. The width of the opaque element is, for example, 10 mm to 100 mm, preferably 20 mm to 70 mm.

[0041] The opaque element is preferably directly attached to the second surface of the glass sheet. In one embodiment of the invention, the opaque element is implemented as an imprint on the second surface of the glass sheet. In this case, 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 in a sufficient amount so that the opaque element is opaque in view of the light of the light source deflected at the light scattering or light diffraction layer, but instead absorbs the light. The color of the opaque element is unimportant. For aesthetic reasons, black may be preferred, but in principle, the opaque element may be of any color.

[0042] The printing paste can be dried after printing and adhere to the glass pane in a purely adhesive manner. However, it is also possible to use enamel-type prints, as is customary in so-called masking prints in vehicle panels. In this case, the printing paste contains glass frit, which is baked into the glass surface after printing, thereby providing a particularly stable bond to the glass surface.

[0043] In another embodiment of the invention, the opaque element is implemented as an opaque component made of rubber or plastic, which is attached, for example glued, to the second surface of the glass plate. The opaque component can be flexible, elastic or even rigid like a film.

[0044] In principle, it is also conceivable that the opaque element is an opaque coating which is applied to the second surface of the glass pane, for example by chemical or physical vapor deposition.

[0045] In the case of a composite pane, in which the second surface of the glass pane faces the interlayer, the opaque element can also be formed on that surface of the thermoplastic interlayer which faces the glass pane and is in contact therewith (e.g. as an opaque imprint) or can be inserted between the interlayer and the second surface of the glass pane (e.g. as an opaque component made of rubber or plastic).

[0046] In operation, the light source emits visible light, i.e. electromagnetic radiation within the visible spectrum, particularly within the range of 380nm to 780nm. The light source may have one or more emission bands, which are arranged within the visible spectrum and cover a portion thereof. However, the light source may also have a wide emission band, which covers the entire visible spectrum. (One or more) emission bands (and therefore the color of the emitted light) may be freely selected according to the requirements of the specific application.

[0047] The glass sheet may contain a single light source, or even a plurality of light sources, the light of which is coupled into the glass sheet at different points. The light of the light source may be coupled into the glass sheet directly, or via an optical element, such as a lens.

[0048] The light source is preferably a light emitting diode (LED). The electroluminescent material of the light emitting diode can be, for example, an inorganic semiconductor or an organic semiconductor. In the latter case, it is also called an organic light emitting diode (OLED).

[0049] The light from the light source can be coupled into the glass pane in various ways, of which three embodiments are particularly preferred.

[0050] In a first preferred embodiment, the light source is associated with a groove in the glass sheet. That is, the glass sheet has a groove. The groove is preferably a hole, i.e. a through hole, which extends between the first and second surfaces of the glass sheet. However, the groove can alternatively also be a blind hole-type depression (pocket-shaped depression) which extends from the first surface or the second surface into the glass sheet, but does not reach the opposite main surface, which will result in a through hole. The blind hole preferably extends from one surface into the glass sheet, forming an exposed surface of the glass element according to the present invention. The light source can then be inserted and easily replaced in the event of a defect. In the case of a composite plate, the surface of the glass sheet that faces away from the interlayer is the exposed surface. For example, the groove can be produced in the glass sheet by mechanical drilling or by laser processing. The groove is preferably circular, but in principle can have any shape, for example even a polygonal shape. This means that the base surface of the groove is located in the plane of at least one surface of the glass sheet, and the groove is introduced into the glass sheet via the plane. The groove generally has the shape of a cylinder, preferably a straight cylinder. The cylindrical body is preferably a circular cylinder (circular base), but can also have any other base, for example an elliptical base (elliptical cylinder) or a polygonal base (prism).

[0051] The groove, whether a through hole or a depression, is delimited by a surrounding edge surface extending between the main surfaces of the glass sheets. In the case of a through hole, this is the only boundary surface of the groove. In the case of a pocket-shaped depression, there is a further boundary surface, which faces the following main surface of the glass sheet, to which the depression does not extend and which, so to speak, forms the bottom of the blind hole. If the glass element comprises a plurality of light sources, a dedicated groove is provided for each light source. However, a plurality of light sources having, for example, different emission colors can be arranged in the same groove.

[0052] In this embodiment, the light source is associated with the edge face of the groove and is suitable for coupling light into the glass sheet via the edge face. For this purpose, the light source itself can be arranged in the groove so that the light source is located in the plane defined by the glass sheet and the emitted light directly hits the edge face. For this purpose, the light source can, for example, be clamped into the groove or glued to the edge face. It is also conceivable that the light source is located in a housing or a support and is fixed there, wherein the housing or the support is inserted into the groove, preferably with an exact fit. Alternatively, it is also possible that the light source does not directly illuminate the edge face, but instead first deflects the radiation for this purpose. Therefore, it is conceivable that the light source is located in a housing, wherein a part of the housing is inserted into the groove, and another part of the housing is located outside the groove. The light source is positioned in the housing part outside the groove, and the light is deflected by a reflective surface or a waveguide in the housing so that the light hits the edge face of the groove. The housing is preferably attached to the exposed surface of the glass sheet and extends from there into the groove.

[0053] In this embodiment, the light trap, i.e. the light scattering or light diffraction layer and the opaque element, is particularly preferably formed completely around the edge region. This means that the light scattering or light diffraction layer and the opaque element each extend along the entire length of the edge region and are each implemented in a frame-like manner without interruption. Therefore, there are no longitudinal sections that are not equipped with a light scattering or light diffraction layer and an opaque element. This reduces or prevents light emission via the entire side edge, which is particularly advantageous.

[0054] In a second preferred embodiment, a light source is associated with one of the two surfaces of the glass sheet. The light source is arranged on one of the surfaces and radiates light into the glass sheet via this surface. An optical coupling device is arranged on the other surface opposite to the light source, and the optical coupling device is suitable for coupling light that passes through the glass sheet and shines on the optical coupling device into the glass sheet via the other surface (i.e. the surface on which the optical coupling device is arranged). The optical coupling device can be implemented, for example, as a microprismatic film, a structured plastic film, or a flatly arranged plastic sheet with microprisms. The optical coupling device reflects the light back into the glass sheet, but reflects it back at a modified angle, which deviates from 0° relative to the surface normal. The light is refracted at the surface of the glass sheet, and at least a portion of the light obtained in the glass sheet shines on the opposite surface at an incident angle greater than the critical angle of total reflection, whereby the light is coupled into the glass sheet.

[0055] The light source is preferably arranged on an exposed surface of the glass pane or glass element so that it can be attached later and, in the event of a defect, can be easily replaced.

[0056] In this embodiment as well, the light trap, ie the light scattering or light diffraction layer and the opaque element are particularly preferably designed completely around the edge region. This reduces or prevents light emission via the entire side edge, which is particularly advantageous.

[0057] In a third preferred embodiment, the light source is associated with the side face of the glass sheet and is suitable for coupling light into the glass sheet via the side face. The light emitted by the light source can directly shine on the side face. The light source can be located at the side of the inner panel in the plane defined by the glass sheet. For this purpose, the light source can be directly attached to the side face, for example glued or clamped. Alternatively, the light source can also be located in a housing or a bracket and fixed there, wherein the housing or bracket is attached to the glass sheet, for example glued or clamped, so that the light source illuminates the side face. However, it is also possible that the light source does not directly illuminate the side face, but first deflects the radiation for this purpose. Therefore, it is conceivable that the light source is located in a housing containing a reflective surface or a waveguide, by which the optical path of the light is shaped. The housing is attached to the glass sheet so that the optical path guides the light to the side face of the glass sheet. The light source itself does not then have to be located at the side of the glass sheet in the plane defined by the glass sheet, but can be arranged, for example, in the perspective direction, in front of or behind the glass sheet. The housing is preferably attached to an exposed surface of the glass sheet and extends therefrom to the side edges of the glass sheet.

[0058] In this embodiment, the light trap, i.e. the light scattering or light diffraction layer and the opaque element are particularly preferably implemented circumferentially in the edge region and are interrupted only at one or more points where the light from the (one or more) light sources is coupled into the glass sheet. Thus, each light source is associated with a longitudinal section of the edge region of the glass sheet via which the light is coupled. The light scattering or light diffraction layer and the opaque element are not present in these longitudinal sections. All other longitudinal sections of the edge region are equipped with light scattering or light diffraction layers and opaque elements along their entire length. This reduces or prevents light emission via the entire side edge, since light radiating from the side edge is prevented either by the light trap or by the light source.

[0059] Combinations of the above-mentioned embodiments are also conceivable, in which a plurality of light sources are present, the light of which is coupled into the glass pane in different ways.

[0060] If the light of the light source is coupled in via the side face of the glass sheet or via the side face of a groove in the glass sheet, in a particularly advantageous embodiment, a central aperture is arranged between the light source and the side face or the side face of the groove. The central aperture is an aperture that blocks the central area of ​​the light beam cone of the light source so that the central area of ​​the side face or the side face is not illuminated by light. The side face or the side face can then be divided into three areas, two of which (edge ​​areas) are respectively arranged adjacent to the surface of the glass sheet and the third area (the central area) is arranged between the two other sections. Light is coupled in via at least one of the edge areas, preferably via two.

[0061] The beam cone of a light source can be divided into three angular groups:

[0062] a first angular group, in which light is coupled into the glass sheet such that it strikes the surface of the glass sheet at an angle of incidence less than the critical angle for total reflection, so that it does not suffer total reflection and is lost via the surface;

[0063] a second angular group, in which light is coupled into the glass sheet so that it strikes the surface of the glass sheet at an angle of incidence greater than the critical angle for total reflection and thus propagates in the glass sheet by total reflection, wherein the angle of incidence is however sufficiently small that the light strikes the light-scattering or light-diffractive layer before it reaches the side facets of the glass sheet; the beam trap acts on this angular group and prevents or reduces emission via the side facets;

[0064] - A third angle group, in which light is coupled into the glass sheet so that the light

[0065] a) passes through the glass sheet and exits again at the opposite side edge without impinging on the surface of the glass sheet, or

[0066] b) The light hits the surface of the glass plate at an incident angle greater than the critical angle for total reflection, but the incident angle is so large that after several total reflections the light reaches the opposite side surface without hitting the light scattering or light diffraction layer (it can be said that the light scattering or light diffraction layer is skipped); the beam trap cannot act on this angle group.

[0067] The central aperture is preselectively dimensioned such that the light of the third angular group is partially or completely blocked. Thus, the light emission via the side edge faces of the glass pane can be further reduced.

[0068] The glass sheet is also equipped with a light scattering structure, which is suitable for coupling the light coupled in out of the glass sheet via the first surface and / or the second surface. For this purpose, the light scattering structure is in direct contact with one of the surfaces so that the light propagating in the glass sheet impinges on it. The light scattering properties of the light scattering structure prevent total reflection. The light scattering structure is, so to speak, a scattering center at which the light is scattered and therefore not completely reflected. Since the scattering is essentially non-directional, at least a portion of the scattered light leaves the glass sheet. Thus, illumination can be achieved or information can be displayed.

[0069] The area of ​​the glass sheet occupied by the light scattering structure appears to the observer as a luminous area. This can, for example, be used for lighting (e.g. the interior) or for realizing a display for presenting information or for creating an aesthetically pleasing luminous surface or pattern. The luminous structure can be present in a single continuous area of ​​the glass sheet or even in a plurality of areas separated from each other. Any shape or pattern can be created using the light scattering structure. In particular, the light scattering structure is arranged in a central area of ​​the glass sheet, which is surrounded by an edge area with a light trap.

[0070] The light scattering structure can be applied directly to the first surface or the second surface of the glass sheet or formed on the first surface or the second surface of the glass sheet. Alternatively, the light scattering structure can be provided, for example, on a carrier film, which is attached to the first surface or the second surface, for example by adhesive bonding. If the glass element according to the invention is a composite panel, the light scattering structure can be applied to the surface of the thermoplastic interlayer in contact with the glass sheet. Alternatively, the light scattering structure (for example applied to a carrier film) can be inserted between the glass sheet and the interlayer.

[0071] In an advantageous embodiment, the light scattering structure is implemented as a mark, in particular as a mark on one of the surfaces of the glass sheet or - in the case of a composite plate - on the surface of the intermediate layer facing the glass sheet. The mark on the glass sheet is preferably implemented as a light scattering enamel. The enamel can be screen printed, for example. It preferably contains glass frit, which is baked into the surface of the glass sheet, thereby creating a rough and therefore light-scattering surface. The mark on the intermediate layer can be achieved in the following way, that is, for example, by screen printing, printing on the surface of a thermoplastic film with a light scattering printing paste. During the manufacture of the composite plate, the film is inserted between the outer plate and the inner plate to form an intermediate layer, wherein the printing surface faces the glass sheet, in particular in direct contact with the glass sheet. In an advantageous embodiment, the light scattering structure is transparent, so that the perspective through the glass sheet is basically unrestricted. Therefore, the mark (enamel or printing paste) preferably does not contain pigments. However, opaque or translucent light scattering structures with pigments are also conceivable, such as white structures.

[0072] However, it is also possible to form light-scattering structures by roughening the relevant surface of the glass pane or of the intermediate layer. This roughening can be done mechanically (for example by grinding techniques) or also by laser processing. Laser processing has the following advantages, in particular in the case of composite panes: light-scattering structures can also be introduced into the finished laminated composite pane, even if they are to be located within the laminate, since the laser radiation can also be focused even on a plane in the interior of the composite pane, for example through a transparent glass pane. In addition, with laser processing it is possible to form light-scattering structures not on the surface but in the interior of the glass pane.

[0073] The glass pane is preferably made of soda-lime glass, which is common for window panes. In principle, 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. Preferably, a pane with a thickness in the range of 0.5 mm to 10 mm, preferably 1 mm to 5 mm, is used. The glass pane is preferably transparent so that light can advantageously propagate in the inner pane.

[0074] In a further development of the invention, the glass element according to the invention is a composite panel. In addition to the glass panel, the composite panel also includes another panel connected to the glass panel via a thermoplastic interlayer. The other panel also has a first surface, a second surface and a peripheral side surface extending between them. If the glass element is a window panel, one of the panels can be called an outer panel and the other panel can be called an inner panel. In the context of the present invention, an "inner panel" refers to the panel of the composite panel facing the interior in the installed position. An "outer panel" refers to a panel facing the external surroundings. The inner side surface of the outer panel and the outer side surface of the inner panel face each other and face the thermoplastic interlayer and are connected to each other via the thermoplastic interlayer.

[0075] In principle, the glass pane with the light source, the light scattering structure and the light trap can be the outer pane or the inner pane of the composite panel. Preferably, the glass pane is the inner pane; and the other pane is the outer pane. Thus, the interior can be illuminated advantageously. The first surface or the second surface of the glass pane can face the interlayer. Particularly preferably, the light scattering structure is applied to the outer surface of the glass pane (inner pane) or formed there, because the light scattering structure is then protected in the interior of the laminate. The same applies to the light scattering structure on the surface of the interlayer that contacts the inner pane.

[0076] The other plate, preferably the outer plate, is preferably made of glass, in particular soda-lime glass. However, the other plate can also be made of other types of glass, such as borosilicate glass, quartz glass, aluminosilicate glass, or transparent plastic, such as polymethyl methacrylate or polycarbonate. The thickness of the outer plate and the inner plate is preferably 0.8 mm to 5 mm, preferably 1.4 mm to 2.5 mm.

[0077] In an advantageous embodiment, the other pane (outer pane) and / or the intermediate layer are tinted. The inner pane (glass pane with light source, light scattering structure and light trap) is preferably transparent. Thus, light can advantageously propagate in the inner pane and the illuminated light scattering structure advantageously appears clearly against the tinted background. The outer pane and / or the intermediate layer are preferably tinted so that the transmittance of the composite pane in the visible spectral range is in the range of 0% to 80%, preferably 2% to 20%, most particularly preferably 4% to 12%. In the case of a transmittance of 0%, the composite pane is only used for lighting and perspective is not possible. In a particularly advantageous embodiment, in particular when the composite pane is a vehicle roof panel, the outer pane is tinted and has a transmittance of 0% to 95% or 2% to 80%, the intermediate layer is tinted and has a transmittance of 0% to 95% or 2% to 80%, and the inner pane is transparent and has a transmittance of more than 80%, in particular more than 90%.

[0078] The thermoplastic intermediate layer comprises at least one layer of thermoplastic bonding material, which preferably contains ethylene vinyl acetate (EVA), polyvinyl butyral (PVB) or polyurethane (PU) or a mixture or copolymer or derivative thereof, particularly preferably PVB. The intermediate layer is usually formed by at least one thermoplastic film. The thickness of the film is preferably 0.3 mm to 2 mm, wherein standard thicknesses of 0.36 and 0.76 are particularly common. The intermediate layer can also comprise multiple layers of thermoplastic material, for example formed by a plurality of polymer films arranged flatly one above the other.

[0079] The composite pane preferably has an opaque shielding area through which perspective is not possible. The shielding area is preferably arranged circumferentially in the edge area of ​​the composite pane and surrounds the central transparent perspective area in a frame-like manner. This is common in particular for vehicle panels. The edge area does not need to coincide with the edge area used to describe the light trap. The shielding area is preferably formed by an opaque shielding print, which is particularly preferably applied at least to the inside surface of the outer pane.

[0080] The invention further comprises a method for producing a lighting glass element according to the invention. A glass sheet is provided and

[0081] - equipped with at least one light scattering structure,

[0082] - light scattering or refractive layers equipped with light traps,

[0083] - an opaque element equipped with a light trap, and

[0084] -Equipped with a light source.

[0085] The individual steps may be performed in any order. Typically, the light source is attached in a last step, especially if this is accessible through an exposed surface of an otherwise finished glass element.

[0086] If the glass element is a composite pane, the glass pane is connected to the other pane via a thermoplastic interlayer. It is then also possible that the light-scattering structure and the light-scattering or light-diffracting layer or the opaque element are not applied to the glass pane, but instead to the interlayer, or are inserted between the interlayer and the glass pane, as already described above. The light source is preferably not applied until after lamination of the composite pane.

[0087] For lamination, methods known per se can be used, such as the autoclave method, the vacuum bag method, the vacuum ring method, the calendaring method, a vacuum laminator or a combination thereof. The joining of the outer and inner panels is usually carried out under the action of heat, vacuum and / or pressure.

[0088] The present invention further includes the use of the glass element according to the invention as a window panel of a vehicle. A particularly preferred use is a vehicle roof panel that is used to illuminate the interior of a vehicle. In principle, the vehicle can be any land vehicle, a ship or an aircraft, and preferably a passenger car, a truck or a rail vehicle. The glass element can also be used in buildings, for example as a window panel, a glass curtain wall or a glass door in an exterior or interior area, in particular as a window panel of a building or interior. The glass element can also be used as a component of furniture, electrical appliances, as a component of a fixture or as a fixture. BRIEF DESCRIPTION OF THE DRAWINGS

[0089] The invention is explained in detail below with reference to the accompanying drawings and exemplary embodiments. The accompanying drawings are schematic diagrams and are not drawn to scale. The accompanying drawings do not limit the invention in any way.

[0090] Figure 1 depicts a plan view of a first embodiment of a glass element according to the invention,

[0091] Figure 2 Describe the path along A–A′ through Figure 1 The cross section of the glass element,

[0092] Figure 3 depicts a plan view of a second embodiment of a glass element according to the invention,

[0093] Figure 4 Describe the path along B–B′ through Figure 3 The cross section of the glass element,

[0094] Figure 5 depicts a plan view of a third embodiment of a glass element according to the invention,

[0095] Figure 6 Describe the path along C–C′ through Figure 5 The cross section of the glass element,

[0096] Figure 7 Schematic diagram depicting the light path within a glass pane of a glass element according to the invention,

[0097] Figure 8 A schematic diagram depicting the light paths in the light trap region of a glass element according to the invention,

[0098] Fig. 9 depicts a cross section through a further embodiment of a glass element according to the invention,

[0099] Fig.10 A cross section through a further embodiment of a glass element according to the invention is depicted. DETAILED DESCRIPTION

[0100] Figure 1 and Figure 2 The details of a first embodiment of a glass element according to the invention are depicted separately. The glass element is implemented as a single glass plate and is structurally formed by a single glass plate 2. The glass plate 2 is made of soda-lime glass and has a thickness of 2.1 mm, for example. The glass plate 2 is shown as being planar, but can be curved cylindrically or spherically, depending on the intended use. The glass plate has two parallel main surfaces, a first surface III and a second surface IV, and a side face e extending therebetween. For simplicity, the side face e is shown as being planar, but in practice is often convexly rounded due to edge grinding.

[0101] The glass plate 2 is equipped with four grooves 4, which extend completely through the glass plate 2 as through holes, that is, from its first surface III to its second surface IV. These grooves 4 have, for example, a circular base and are bounded by surrounding edge faces i. The grooves 4 generally have the shape of a cylinder, wherein the edge faces i form the side faces, and the base of the cylinder is provided by the inlet and outlet of the groove in the first surface III or the second surface IV. For example, a light source 5 glued to the edge faces i is inserted into the grooves 4 respectively. The light source 5 is implemented as a light emitting diode (LED), for example. In operation, the light source emits visible light, which is coupled into the glass plate 2 through the edge faces i and propagates there due to total reflection on its surfaces III and IV. A light scattering structure 6 made of transparent enamel is also printed on the second surface IV of the inner plate 2. When the light of the light source 5 shines on these light scattering structures 6, the light is scattered and thus coupled out of the glass plate 2. The light scattering structure 6 appears to the observer as a luminous surface that can be used for lighting, for example.

[0102] In addition to the radiation components which impinge on the light-scattering structure 6, in conventional panes of this type, those radiation components which impinge on the side faces are also coupled out. The side faces e therefore also emit unwanted and possibly interfering radiation.

[0103] In order to reduce the undesired emission through the side face e, a completely surrounding light trap is formed in the edge region of the glass plate 2. The light trap is formed by a light scattering or light diffraction layer 7 on the first surface III and an opaque element 8 on the second surface IV. When the light in the glass plate 2 reaches the edge region, the light is scattered or diffracted at the light scattering or light diffraction layer 7, whereby the total reflection is interrupted. The light is at least partially deflected toward the opaque element 8, through which the light is absorbed. As a result, the light does not reach the side face e or reaches the side face to a lesser extent, whereby emission through the side face e is prevented or at least reduced.

[0104] The light scattering or light diffraction layer 7 and the opaque element 8 are respectively completely circumferentially extending along the contour of the glass plate 2, particularly parallel to the periphery, in a strip-shaped manner. The strips are respectively defined by two side edges, wherein one side edge faces the side face e of the glass plate 2, and the other side edge faces away from the side face e. The light scattering or light diffraction layer 7 has, for example, a width of 30 mm (strip width, the distance between the sides). The side edge facing the side face e has, for example, a distance of 10 mm from the side face e. Correspondingly, the side edge facing away from the side face e has, for example, a distance of 40 mm from the side face e. Therefore, the light scattering or light diffraction layer 7 is spaced apart from the side face e as a whole. The opaque element 8 has, for example, a width of 30 mm (strip width, the distance between the sides). The opaque element is directly adjacent to the side face e. Therefore, the side edge facing the side face e has a distance of 0 mm from the side face e. Correspondingly, the side facing away from the side edge surface e has a distance of, for example, 30 mm from the side edge surface e.

[0105] The light scattering or light diffraction structure 7 can be implemented, for example, as a grating or microprismatic film and can be glued to the first surface III. Alternatively, the light scattering or light diffraction structure 7 can be implemented as a scattering imprint on the first surface III, similar to the light scattering structure 6 for coupling out light. The opaque element 8 can be, for example, an opaque imprint on the second surface IV or a glued-on opaque component made of rubber or plastic.

[0106] Figure 1 Depicted is a plan view of a first surface III of a glass pane 2 . The light-scattering structure 6 and the edge region of the opaque element 8 are visible in a perspective through the transparent glass pane 2 .

[0107] Figure 3 and Figure 4 The details of a second embodiment of a glass element according to the invention are respectively depicted. The glass element substantially corresponds to Figure 1 and 2 The glass element has a single glass plate 2, a light scattering structure 6 and a light trap consisting of a light scattering or light diffraction layer 7 and an opaque element 8, which are implemented 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.

[0108] Three light sources 3 are attached, for example glued, to the side face e of the glass plate 2, and light is coupled in through the side face e, which then propagates in the glass plate 2 due to total reflection on the surfaces III, IV. The light source 5 is also implemented here, for example, as a light emitting diode (LED). The section of the edge area of ​​the glass plate 2 adjacent to the section of the side face e with the light source 5 is not equipped with a light trap. The light scattering or light diffraction layer 7 and the opaque element 8 are completely arranged around the edge area, but are interrupted at the point where the light coupling occurs. Therefore, the light coupling is not disturbed by the light trap, which would prevent total reflection. When the light reaches the side face e after passing through the glass plate 2, the undesired emission via the side face e is prevented or at least reduced by the light trap.

[0109] Figure 3 The first surface III of the glass pane 2 is depicted in plan view again. The edge regions of the light-scattering structure 6 and the opaque element 8 are visible in perspective through the transparent glass pane 2. The section line BB′ passes through the interruption of the light trap, so that the light-scattering or light-diffractive layer 7 and the opaque element 8 are visible in the perspective through the transparent glass pane 2. Figure 4 It is visible behind the section plane and is therefore not shown in a hatched manner.

[0110] Figure 5 and Figure 6 The details of a third embodiment of a glass element according to the invention are respectively depicted. The glass element substantially corresponds to Figure 1 and 2 The glass element has a separate glass plate 2, a light scattering structure 6 and a light trap consisting of a light scattering or light diffraction layer 7 and an opaque element 8, which is implemented in the same way as in the first embodiment. The second embodiment differs from the first embodiment in the type of light coupling.

[0111] Four light sources 5 are attached, for example glued, to the second surface IV of the glass plate 2. Opposite to each light source 5, a light coupling device 11, for example implemented as a microprismatic film, is attached to the first surface III. The light coupling device 11 is illuminated by the light source 5 through the glass plate 2. The light then reenters the glass plate 2 via the first surface III at a modified beam angle and propagates therein by total reflection. Thus, the light is coupled into the glass plate 2 via the first surface III by means of the light coupling device 11. The light radiation is indicated by arrows in the figure.

[0112] In order to reduce the unwanted emission via the side edge face e, a completely surrounding light trap is implemented in the edge region of the glass sheet 2. The light trap is formed completely surroundingly in the edge region of the glass sheet 2 in order to reduce the light emission via the side edge face e. The light scattering or light diffraction layer 7 and the opaque element 8 are not interrupted in any longitudinal section of the edge region.

[0113] Figure 5Once again a plan view of the first surface III of the glass pane 2 is depicted. The light-scattering structure 6 and the edge region of the opaque element 8 are visible in a perspective through the transparent glass pane 2 .

[0114] Figure 7 The propagation of light from the light source 5 in the glass plate 2 is shown. The light strikes the glass plate 2 from the inside on its surfaces III and IV, which are interfaces from a medium with a greater optical density to a medium with a lesser optical density. Therefore, there is a critical angle α for total reflection T The critical angle is determined by the refractive index n1 of the glass plate 2 and the refractive index n2 of the surrounding air. At a wavelength of 589 nm, for the transition from soda-lime glass (n1 = 1.52) to air (n1 = 1.0), the critical angle α T For example, 41°.

[0115] The portion of light coupled into the glass plate 2 with a beam greater than the critical angle α T The incident angle α is irradiated onto the surfaces III and IV of the glass plate. These light rays are completely reflected at a reflection angle α′ which is equal in magnitude to the incident angle α. The reflection at the first surface III is shown. The incident light and the reflected light are indicated by arrows. The reflected light passes through the glass plate 2 again all the way to the second surface IV, where it is again irradiated onto the second surface at an incident angle α, so that it is completely reflected again. The propagation of light in the glass plate 2 will continue in this manner until the light hits the light scattering structure 6 and is coupled out via the surfaces III and IV (which is desired) or reaches the side surface e and is emitted via the side surface e (which is undesirable).

[0116] The angle of incidence α and the angle of reflection α′ are referenced to the surface normal of the reflecting surface, as is conventionally done.

[0117] Figure 8 The effect of the light beam trap according to the invention for reducing the unwanted emission through the side edge face e is shown. In the edge region of the glass sheet 2, the light impinges on the light scattering or light diffraction layer 7. This prevents total reflection. At least part of the light is reflected back into the glass sheet 2 by the light scattering or light diffraction layer 7 at a reflection angle β which is significantly smaller than the angle of incidence α. As a result, the light is deflected toward the opaque element 8, which absorbs the light. As a result, the light trap at least partially intercepts the light before it reaches the side edge face e. As a result, at least the emission via the side edge e is reduced.

[0118] The width and relative arrangement of the light-scattering or light-diffractive layer 7 and the opaque element 8 can be selected in the specific application so that the greatest possible proportion of the light that would reach the side edge e without the light trap is intercepted. They depend in particular on the thickness of the glass sheet 2, the wavelength of the light and the material of the glass sheet 2 and the surroundings (the wavelength and the material determine the refractive index and thus the critical angle α). T ), the design of the light scattering or light diffraction layer 7 (which affects the reflection angle β).

[0119] Fig. 9 A further development of the glass element according to the invention is shown. A cross section through a section of a glass pane 2 is shown, on the side face e of which a light source 5 is mounted. A central aperture 10 is arranged between the light source 5 and the side face e. The central aperture 10 prevents light from entering the central section of the side face e, so that the coupling of light occurs only via the section of the side face e that is directly adjacent to the surfaces III, IV and between which the central section is arranged.

[0120] The light source 5 illuminates the side face e over a specific angle range according to its beam cone. With regard to the coupling, a distinction can be made between three angle groups.

[0121] In the first angle group, light strikes surfaces III and IV near the side surface e at a small incident angle α (indicated by thin solid arrows in the figure). The incident angle α is less than the critical angle α of total reflection. T . These radiation components are not completely reflected, but are mostly refracted at the corresponding surface and mostly leave the glass sheet via the corresponding surface. The radiation reflected to a small extent strikes the opposite surface, where it is mostly refracted again. Therefore, for the intended light coupling, the light of the first angle group is lost. Emission via the surfaces III, IV in the vicinity of the light source 5 can optionally be prevented, for example by an opaque imprint which absorbs the radiation of the first angle group.

[0122] In the second angle group, the light (at a greater distance from the side face e than the light in the first angle group) strikes the surfaces III, IV at a greater angle of incidence α (indicated by the thick solid arrows in the figure). The angle of incidence α is greater than the critical angle α for total reflection. T The light propagates in the glass plate 2 as described above (see Figure 7 ) and is used for the intended illumination of the light scattering structure 6.

[0123] In the third angle group, it can be said that the light will be coupled into the glass plate 2 more evenly than in the second angle group. The light in the third angle group will be

[0124] - passes through the glass plate 2 between the surfaces III, IV and strikes the side face e opposite the light source 5, without striking one of the surfaces III, IV and being completely reflected therefrom (indicated by a dotted arrow in the figure),

[0125] - Alternatively, the light is incident on surfaces III, IV of the glass plate 2 at such a large angle of incidence that the light is completely reflected only a few times, with the reflection points being so far apart that no reflection points exist in the area of ​​the light-scattering or light-diffraction layer 7; the light-scattering or light-diffraction layer 7 is therefore skipped, so to speak.

[0126] In both cases, the light trap according to the invention cannot act on the radiation of the third angular group and cannot prevent emission via the side face e.

[0127] The central aperture 10 causes the light of the third angular group to be blocked and not coupled into the glass pane 2. As a result, the emission via the side edge e can be further reduced. The size of the central aperture 10 is ideally selected according to the specific application so that, on the one hand, the light of the third angular group is blocked as completely as possible and, on the other hand, the light of the second angular group is not blocked as much as possible or is blocked only to a small extent.

[0128] The principle of the central aperture 10 has been explained here using the example of an embodiment in which light is coupled into the glass plate 2 via the side face e (e.g. Figure 3 and 4 If the light is coupled in via the edge faces i of the groove 4, the central aperture 10 can be used in exactly the same way (as in Figure 1 and 2 middle).

[0129] In all embodiments, light emission from the first angle group can be prevented by opaque shielding printing, opaque stickers or similar opaque elements near those locations where light is coupled in, regardless of whether the light occurs via the side edge face e, the edge face i of the groove or through the light coupling device 11 on one of the surfaces III, IV. The opaque element is arranged in the area of ​​the (one or more) surfaces of the glass sheet that is illuminated by the light of the first angle group.

[0130] Fig.10 A cross section through another embodiment of a glass element according to the invention is depicted. The glass element is embodied as a composite pane. The composite pane comprises a glass pane 2 which is substantially as in Figure 1 and 2 , with a light source 5 in the recess 4, a light scattering structure 6 on the second surface IV and a light trap which is formed circumferentially in the edge region by a light scattering or light diffraction layer 7 and an opaque element 8.

[0131] The glass pane 2 is connected to the further pane 1 via a thermoplastic intermediate layer 3. The further pane 1 is likewise a pane made of soda-lime glass with a thickness of, for example, 2.1 mm.

[0132] The composite panel is intended to be used as a vehicle roof panel. For simplicity, the composite panel is shown as flat, where the vehicle roof panel is usually curved. The glass panel 2 is the inner panel of the composite panel, which faces the interior of the vehicle in the installed position. Its first surface III is its outer surface, which faces the other panel 1 and the external surrounding environment in the installed position. Its second surface IV is its inner surface, which faces the interior of the vehicle in the installed position. The other panel 1 is the outer panel of the composite glass panel, which faces the external surrounding environment in the installed position. The other panel 1 also has a first surface or outer surface I, which faces the external surrounding environment in the installed position, and a second surface or inner surface II, which faces the glass panel 2 and the interior of the vehicle in the installed position. The inner surface II of the other panel 1 (outer panel) and the outer surface III of the glass panel 2 (inner panel) face each other and are connected to each other via a thermoplastic interlayer 3. The interlayer 3 is formed by a single film based on PVB, with a thickness of, for example, 0.76 mm. The other pane 1 and the interlayer 3 are, for example, tinted, while the glass pane 2 is made of transparent glass. Due to this tinting, the total transmission through the composite pane is, for example, less than 5%.

[0133] The inner surface II of the other panel 1 is provided with a shielding print 9 in the peripheral edge region, which forms an opaque shielding region of the composite panel, as is customary in the case of vehicle panels. Recesses 4 with light sources 5 are arranged in this shielding region, whereby they are advantageously inconspicuous. The same applies to the light trap comprising a light-scattering or light-diffraction layer 7 and an opaque element 8.

[0134] List of reference numerals:

[0135] (1) Another board

[0136] (2) Glass plate

[0137] (3) Thermoplastic intermediate layer

[0138] (4) Groove of glass plate 2

[0139] (5) Light source

[0140] (6) Light scattering structure

[0141] (7) Light scattering or light diffraction layer

[0142] (8) Opaque components

[0143] (9) Masking printing

[0144] (10) Center aperture

[0145] (11) Optical coupling device

[0146] (I) First / outer surface of the other plate 1

[0147] (II) Second / inner surface of the other plate 1

[0148] (III) First Surface of Glass Plate 2

[0149] (IV) Second Surface of Glass Plate 2

[0150] (e) Side surface of glass plate 2

[0151] (i) The side surface of the groove 4

[0152] α Τ Critical angle of total reflection

[0153] α The incident angle of the light

[0154] α′ Reflection angle of light during total reflection (α=α′)

[0155] β Reflection angle of light emitted from the light scattering / light diffraction layer 7

[0156] AA′ hatch line

[0157] BB′ hatch

[0158] CC′ section line.

Claims

1. A lighting glass element, comprising a glass plate (2), wherein the glass plate (2) has a first surface (III), a second surface (IV) and a side surface (e) extending therebetween, wherein the glass plate (2) - equipped with at least one light source (5) suitable for coupling light into the glass sheet (2) so that the light propagates in the glass sheet (2), in particular by total reflection at 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 the light out of the glass sheet (2) via the first surface (III) and / or via the second surface (IV), It is characterized in that The glass pane (2) is equipped at least in sections in the peripheral edge region with a light trap, which is suitable for reducing light emission via the side face (e), The light trap is formed by a light scattering or light diffraction layer (7) on the first surface (III) and an opaque element (8) on the second surface (IV).

2. A lighting glass element according to claim 1, wherein the light-scattering or light-diffracting layer (7) is suitable for deflecting light incident thereon towards the opaque element (8).

3. The lighting glass element according to claim 1 or 2, wherein the light-scattering or light-diffracting layer (7) is embodied as a grating, an imprint, a microprismatic film or a structured coating.

4. A lighting glass element according to any one of claims 1 to 3, wherein the light scattering or light diffraction 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.

5. The lighting glass element according to claim 4, wherein the light scattering or light diffraction layer (7) has a distance from the side edge face (e) of 0 mm to 35 mm, preferably 5 mm to 20 mm.

6. The lighting glazing element according to any one of claims 1 to 5, wherein the opaque element (8) is embodied as an imprint or as an opaque component made of rubber or plastic.

7. The lighting 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 surface (e) with a width of 10 mm to 100 mm, preferably 20 mm to 70 mm.

8. The lighting glass element according to claim 7, wherein the light-scattering or light-diffracting layer (7) is directly adjacent to the side edge face (e).

9. The lighting glass element according to claim 1 , wherein the glass plate ( 2 ) has a groove ( 4 ) which is delimited by a circumferential edge surface (i), and wherein the light source ( 5 ) is arranged in or on the groove ( 4 ) such that the light source is suitable for coupling light into the glass plate ( 2 ) via the edge surface (i), and wherein the light trap is formed completely circumferentially in the edge region.

10. The lighting glass element according to claim 1 , wherein the light source ( 5 ) is arranged on one of the surfaces (III, IV) and, opposite thereto, a light coupling device ( 11 ) is arranged on the other surface (III, IV), the light coupling device being suitable for coupling light that passes through the glass sheet (2) and impinges on the light coupling device ( 11 ) into the glass sheet (2), and wherein the light trap is formed completely around the edge region (R).

11. The lighting glazing element according to claim 1 , wherein at least one light source ( 5 ) is arranged on a side face (e) such that the light source is suitable for coupling light into the glass pane ( 2 ) via the side face (e), And wherein the light trap is formed circumferentially in the edge region (R) and is interrupted only at one or more points where light is coupled into the glass sheet (2).

12. The lighting glazing element according to claim 9 or 11, wherein a central aperture is arranged between the light source (5) and the edge face (i) or the side edge face (e).

13. The lighting glazing element according to any one of claims 1 to 12, wherein the light source (5) is a light emitting diode.

14. The lighting glass element according to any one of claims 1 to 13, comprising a further pane (1) which is joined to the glass pane (2) via a thermoplastic intermediate layer (3).

15. Use of a lighting glazing element according to any one of claims 1 to 14 as a window panel for vehicles, buildings or interiors, as a component of furniture, electrical appliances, as a component of a fixture or as a fixture, preferably as a vehicle roof panel.

Images