Composite panel for a luminescable glazing element

Abstract

The invention relates to a composite panel (100) for a luminous glazing element (101), comprising:-an outer panel (1),-an inner panel (2) having an outer side surface (III) facing the outer panel (1) and an inner side surface (IV) facing away from the outer panel (1),-an adhesive intermediate film (3.1) arranged between the inner panel (2) and the outer panel (1), the present invention relates to an outer panel (1), an inner panel (2), and an adhesive intermediate film (3.1) attached to one of the surfaces (i, ii) of the outer panel (1) and having an outer surface (i) facing the outer panel (1) and an inner surface (ii) facing the inner panel (2), and a low refractive index layer (4) attached to one of the surfaces (i, ii) of the adhesive intermediate film (3.1), the refractive index of the low refractive index layer (4) being lower than the refractive index of the inner panel (2) by a value of at least 0.1, the adhesive intermediate film (3.1) having a layer thickness of 5 m to 100 m.

Description

Technical Field

[0001] The present invention relates to a sandwich panel for a luminescent glass window element, and a luminescent glass window element having such a sandwich panel. Background Technology

[0002] Illuminating glass window elements are known in themselves. They are equipped with a light source, the light of which is coupled into a light guide (usually a glass panel) and propagates due to total internal reflection. The light is often coupled back out of the light guide through a light scattering element, thus achieving illumination. The shape of the light scattering element can be freely chosen, allowing the creation of luminescent surfaces of arbitrary shapes, such as patterns. Such luminescent glass window elements are known, for example, from WO2014 / 060409A1 or WO2014 / 167291A1.

[0003] In the automotive industry, these luminescent glass window elements are particularly appealing as roof panels and windshields or windows in trains or buses. The glass window elements are typically designed as laminated panels, with light coupled into their inner panels. However, these luminescent glass window elements can also be used as panels in other vehicles, or in the building and construction industry, or in furniture. The light-scattering structure generates a luminescent surface that can be used to display aesthetically pleasing shapes and patterns, or to display information such as directional arrows, status indicators, warning notices, price lists, etc.

[0004] Various options for coupling light from a light source into a light guide designed as a glass panel are known. The light source (typically a light-emitting diode) can be arranged on the side edges, allowing light to illuminate the glass panel through the side edges and thus couple in. However, this coupling in is often impossible, particularly because the side edges of the glass panel are typically polished to improve mechanical strength, resulting in hazy side edges. Furthermore, arrangement at the edges of the panel is difficult to achieve because a glass panel with a light source arranged in this way would lose stability.

[0005] Alternatively, the light source can be arranged in a recess in the glass panel (e.g., in a feedthrough), so that light shines into the glass panel through the side edge surface of the recess and is thus coupled in. However, drilling a recess would significantly complicate the production of such a glass window element and involve the risk of a higher scrap rate due to glass breakage.

[0006] US2020241189A1 proposes allowing light to couple in via the main surface of a glass panel. For this purpose, a reflective structure is attached to the surface of the glass panel facing away from the light source. The reflective structure has portions that are angled toward each other. When the light source illuminates the reflective structure through the glass panel, the light is reflected at the angled portions, causing it to propagate within the glass panel due to total internal reflection on the surface.

[0007] WO2008059170A2 discloses a light-emitting glass window element using a porous coating. The porous coating has a lower refractive index than the inner panel. The coating is primarily used to reduce light reflection in architectural glass windows or to improve the efficiency of solar cells. Simultaneously, it aims to improve the visual appearance of the glass window element. WO2020156737A1 relates to a panel with PDLC elements. The panel is designed as a sandwich panel, wherein the PDLC elements are arranged between an inner panel and an outer panel. The PDLC elements serve not only as optically switchable functional elements but also as light-scattering structures for light coupled into the panel. A barrier layer in the form of a film or coating on the panel helps ensure that light does not couple out through the outer panel into the interior but instead through the inner panel. WO2023209206A1, published after the priority date, discloses a sandwich panel capable of guiding light. To prevent harmful light coupling away, an optically low refractive index layer is applied to the surface of the optical waveguide facing the intermediate layer.

[0008] In all general solutions used for coupling light, most of the light emitted by the light source is lost because it is technically almost impossible to couple 100% of the light, or if the light has already been coupled into the light guide, some unwanted light may be coupled away. Summary of the Invention

[0009] The object of the present invention is to provide an improved sandwich panel for an illuminated window unit, wherein light from a light source intended to be coupled into the sandwich panel can be utilized more efficiently, and wherein the sandwich panel should be cost-effective for production and have high stability.

[0010] The object of the present invention is achieved by the sandwich panel according to claim 1. Preferred embodiments are derived from the dependent claims.

[0011] The sandwich panel for a light-emitting glass window element according to the present invention comprises at least an outer panel, an inner panel, an adhesive interlayer, and a low-refractive-index layer. The adhesive interlayer is disposed between the outer panel and the inner panel, and has an outer surface facing the outer panel and an inner surface facing the inner panel. The inner panel has an inner surface facing away from the adhesive interlayer and an outer surface facing the adhesive interlayer. The low-refractive-index layer is applied to one of the surfaces of the adhesive interlayer, meaning that the low-refractive-index layer can be applied to either the outer surface or the inner surface of the adhesive interlayer.

[0012] The inlay is designed to guide light, particularly visible light (400 nm to 800 nm). Therefore, the inlay can be used as a light guide. The low-refractive-index layer has a refractive index at least 0.1 lower than that of the inlay. When the low-refractive-index layer is applied to the outer surface of the adhesive interlayer, the adhesive interlayer preferably has a refractive index that differs from that of the inlay by less than 0.1, and particularly preferably less than 0.05. Specifically, in this case, the adhesive interlayer has a refractive index between that of the low-refractive-index layer and the inlay. This allows the adhesive interlayer to be used as a light guide layer.

[0013] A sandwich panel is provided to separate the interior from the exterior environment in window openings of a vehicle or building. In this context, within the meaning of this invention, "inner panel" refers to a panel facing inwards (the interior of the vehicle). "Outer panel" refers to a panel facing outwards. However, the invention is not limited thereto. The inner surface of the inner panel is also the inner surface of the sandwich panel. The outer panel has an outer surface facing away from the adhesive interlayer and an inner surface facing the adhesive interlayer. The outer surface of the outer panel is also the outer surface of the sandwich panel.

[0014] Within the meaning of this invention, "light guide" refers to a light-guiding medium, preferably a glass or plastic panel, designed to allow light to be coupled into the light guide via total internal reflection, and also suitable for guiding coupled light. The principle of guiding light using total internal reflection is generally known to those skilled in the art and is described in more detail, for example, in WO2008 / 047442A1, JP2011086547A, or JP2015043321A. Therefore, the light guide is designed to allow light from a light source to be coupled into the light guide (in this example, the panel) and to propagate therein.

[0015] The inner and outer surfaces of the insert form an interface with the adjacent medium. For example, the outer surface of the insert is the interface with a viscous interlayer or a low-refractive-index layer. The inner surface of the insert, for example, is the interface with the surrounding atmosphere. Typically, the medium adjacent to the inner surface (e.g., the internal atmosphere) has a different refractive index than the insert. When the adjacent medium has a different refractive index than the insert, this results in a critical angle for total internal reflection, which is determined as: in n 1 The refractive index of a medium with high optical density, and n 2 The refractive index is the refractive index of a medium with low optical density. In the case of the interface between the inlay and air, the refractive index of the inlay is specified as... n 1 And the refractive index of air is specified as n 2If light strikes an interface at an angle of incidence greater than the critical angle, the light will be completely internally reflected (total internal reflection). As is common in geometrical optics, the angle of incidence is the angle between the incident light beam and the normal surface of the surface at the point of incidence. The angle of reflection is similarly determined relative to the normal surface, as is the critical angle for total internal reflection.

[0016] Adhesive interlayers are used as components of thermoplastic interlayers or thermoplastic interlayers. The interlayer bonds the outer panel and the inner panel together, making them interconnected.

[0017] The inventors unexpectedly discovered that light can couple in particularly efficiently if at least one layer adjacent to the inlay or adhesive interlayer has a refractive index at least 0.1 lower than that of the inlay. The lower refractive index of the low-refractive-index layer results in a smaller critical angle, which increases the range of light coupling in under total internal reflection. Unless the low-refractive-index layer is positioned between the inlay and the adhesive interlayer, light coupled into the light guide will also be partially coupled into the adhesive interlayer. Therefore, the light guide medium constituting the inlay can also include an adjacent adhesive interlayer, allowing light to reflect back and forth between the low-refractive-index layer and the inner surface of the inlay (guided by total internal reflection).

[0018] In a preferred embodiment of the invention, at least one light scattering element is disposed between the inlay panel and the low refractive index layer. Preferably, at least two light scattering elements are disposed between the inlay panel and the low refractive index layer, particularly preferably at least three light scattering elements, and especially at least five light scattering elements. In addition to, or independently of, the light scattering elements mentioned above, one or more light scattering elements may be applied to or integrated on or within the inner surface of the inlay panel.

[0019] In a further preferred embodiment of the invention, at least one light scattering element is applied to the inner or outer surface of the inlay panel, preferably only to the outer surface.

[0020] Depending on the design of the sandwich panel, at least one light scattering element can be arranged at different points within the sandwich panel. Some possible embodiments of the sandwich panel are given below, where the layer order given also represents the order of the layer structure of the sandwich panel: 1. At least one light scattering element – ​​inner panel – low refractive index layer – adhesive interlayer – outer panel, 2. At least one light scattering element – ​​inner plate – adhesive interlayer – low refractive index layer – outer plate. 3. Inner panel - at least one light scattering element - low refractive index layer - adhesive interlayer - outer panel, 4. Inner panel - at least one light scattering element - adhesive interlayer - low refractive index layer - outer panel, or 5. Inner panel - adhesive interlayer - at least one light scattering element - low refractive index layer - outer panel.

[0021] In the context of this invention, a "light scattering element" refers to an element suitable for coupling light away from an inlay or light-guiding medium (e.g., an adhesive interlayer). Light coupled to the inlay and, if applicable, to the surrounding adhesive interlayer propagates until it encounters a side edge surface of the inlay / adhesive interlayer, or encounters a light scattering element and couples away there. Preferably, the light scattering element is arranged such that most of the coupled light couples away from the interlayer inlay at at least one light scattering element. If the coupled light encounters a light scattering element, total internal reflection is interrupted, and the light instead couples away from the light-guiding medium.

[0022] At least one light-scattering element can be designed, for example, as an imprint. The light-scattering element is preferably arranged on the inner surface or outer surface of the panel. The imprint on the panel is preferably in the form of light-scattering enamel. This enamel can be applied, for example, by screen printing. It preferably comprises a glass frit that is ablated into the surface of the panel, thereby creating a rough and therefore light-scattering surface.

[0023] In a further embodiment, at least one light-scattering element is an imprint applied to the adhesive interlayer and / or disposed on at least one further adhesive interlayer between the low-refractive-index layer and the inlay. The at least one further adhesive interlayer preferably has a refractive index that differs from the refractive index of the inlay by less than 0.1. Particularly preferably, the at least one further adhesive interlayer has the same refractive index as the adhesive interlayer. The imprint on the adhesive interlayer can be achieved by printing a light-scattering printing paste on one surface of the interlayer. The imprint (printing paste) is preferably pigment-free and therefore transparent. Alternatively, the transparent imprint may also contain pigments, such as TiO2 pigments. In a further embodiment of the invention, the printing paste is opaque, translucent, or colored due to dyes and / or colored pigments.

[0024] In a particularly advantageous embodiment, the light-scattering element is transparent, so that it does not substantially restrict the view through the mezzanine panel. However, it is also conceivable to use opaque or translucent light-scattering elements with pigments (e.g., white structures). The light-scattering element can also produce colored hues, i.e., at least not completely blocking the view through the mezzanine panel, but allowing it to present one or more hues.

[0025] A light-scattering element presents itself as a luminescent surface of a sandwich panel. For example, it can be used to illuminate interiors, and in particular, to display symbols or patterns intended to convey information or for purely aesthetic purposes. Any shape or pattern can be achieved using a light-scattering element.

[0026] In a preferred embodiment, at least one light-scattering element can be configured as a film. Any further light-scattering elements present can also be configured as films. The film is disposed, for example, between an inner panel and an adhesive interlayer. Alternatively or additionally, the film can also be disposed between an adhesive interlayer and a further adhesive interlayer. The low-refractive-index layer is always disposed closer to the outer panel than at least one light-scattering element. The light-scattering element in film form can also be disposed within the adhesive interlayer. The film can be disposed, for example, by pressing within a specific layer. In this case, the specific layer completely encloses the film. This arrangement of the film can produce particularly efficient coupling separation.

[0027] However, light-scattering elements in interior panels designed as glass or plastic panels can also be formed by roughening the relevant surfaces of the interior panel. This roughening can be achieved mechanically (e.g., by grinding techniques) or by laser processing. Laser processing has the advantage that, particularly in the case of sandwich panels, the light-scattering structure can be incorporated into the finished sandwich panel even if it is located inside the panel, because the laser beam can be focused onto a plane inside the panel. Laser beam processing also allows for the formation of light-scattering structures inside the glass panel rather than on its outer surface.

[0028] The adhesive interlayer is preferably disposed on the inner panel. If a low-refractive-index layer is applied to the outer surface of the adhesive interlayer, the adhesive interlayer is preferably applied to the inner panel, i.e., in direct spatial contact with the inner panel. This spatial contact can be interrupted in some areas by light-scattering elements disposed between the adhesive interlayer and the inner panel. The low-refractive-index layer can be disposed between the adhesive interlayer and the inner panel such that the low-refractive-index layer is in spatial contact, for example, with the inner surface of the adhesive interlayer and the outer surface of the inner panel. The spatial contact between the low-refractive-index layer and the inner panel can be interrupted in some areas by light-scattering elements disposed between the inner panel and the low-refractive-index layer.

[0029] In a further preferred embodiment of the invention, at least one further adhesive interlayer, preferably exactly one further adhesive interlayer, is disposed between the inlay and the adhesive interlayer. The further adhesive interlayer has a refractive index that preferably differs from that of the inlay by less than 0.1; preferably, the further adhesive interlayer has the same refractive index as the inlay. The further adhesive interlayer preferably does not contain plasticizers. Therefore, the further adhesive interlayer has higher dimensional stability and stiffness, allowing the light scattering element to hold better after lamination, and if designed for printing, it can be printed more effectively. The further adhesive interlayer preferably has a layer thickness of 5 μm to 200 μm, particularly preferably 10 μm to 100 μm, and especially 25 μm to 75 μm.

[0030] During lamination, an adhesive interlayer and at least one further adhesive interlayer are fused to form an interlayer that connects the inner panel to the outer panel. A further adhesive interlayer may also be disposed between the adhesive interlayer and the outer panel.

[0031] The following provides a further preferred embodiment of the sandwich panel, wherein the layer order given herein also indicates the order of the layer structure of the sandwich panel: 1. Inner panel – Further adhesive interlayer – Low refractive index layer – Adhesive interlayer – Outer panel, 2. Inner panel - further adhesive interlayer - adhesive interlayer - low refractive index layer - outer panel, 3. Inner panel - two further adhesive interlayers - low refractive index layer - adhesive interlayer - outer panel, or 4. Inner panel - two further adhesive interlayers - adhesive interlayer - low refractive index layer - outer panel.

[0032] Preferably, if the low-refractive-index layer is adjacent to the outer panel or the inner panel, the adhesive interlayer is disposed between the low-refractive-index layer and the outer panel or the inner panel to ensure sufficient adhesion.

[0033] The following provides a further preferred embodiment of a sandwich panel having at least one light scattering element and a further viscous interlayer, wherein the layer order given herein also indicates the order of the layer structure of the sandwich panel: 1. At least one light scattering element – ​​inner plate – further adhesive interlayer – low refractive index layer – adhesive interlayer – outer plate, 2. At least one light scattering element – ​​inner plate – further adhesive interlayer – adhesive interlayer – low refractive index layer – outer plate, 3. Inner panel - at least one light scattering element - further adhesive interlayer - low refractive index layer - adhesive interlayer - outer panel, 4. Inner panel - at least one light scattering element - further adhesive interlayer - adhesive interlayer - low refractive index layer - outer panel, or 5. Inner panel – Additional adhesive interlayer – Adhesive interlayer – At least one light scattering element – ​​Low refractive index layer – Outer panel.

[0034] Preferably, if the low-refractive-index layer is adjacent to the outer panel or the inner panel, the adhesive interlayer is disposed between the low-refractive-index layer and the outer panel or the inner panel to ensure sufficient adhesion.

[0035] The adhesive interlayer and any further adhesive interlayers present preferably comprise polyvinyl butyral (PVB), ethylene-vinyl acetate copolymer (EVA), thermoplastic polyurethane (TPU), polyacrylate compounds (e.g., polyacrylate or polymethacrylate), and / or silicone. The adhesive interlayer preferably does not contain polyethylene terephthalate (PET). The adhesive interlayer and any further adhesive interlayers present are preferably optically clear adhesives (OCA). Particularly preferably, the adhesive interlayer and any further adhesive interlayers present are based on PVB, EVA, TPU, polyacrylate compounds (e.g., polyacrylate or polymethacrylate), or silicone, and particularly they are composed of the aforementioned materials. If a further adhesive interlayer is formed in addition to the adhesive interlayer, the further adhesive interlayer may be different from or the same as the adhesive interlayer. These materials are well-suited for use as adhesive layers in sandwich panels for connecting panels. The adhesive interlayer formed based on PVB preferably has a refractive index of 1.48.

[0036] If something is formed "based" on a polymer material, then it is primarily composed of that material, i.e., at least 50%, preferably at least 60%, and particularly at least 70%. Therefore, it may also contain further materials, such as, for example, stabilizers or plasticizers.

[0037] The viscous interlayer and any further viscous interlayer present are preferably free of plasticizers. Typical plasticizers are aliphatic diesters of triethylene glycol or tetraethylene glycol, such as triethylene glycol bis(2-ethylhexanoate). Suitable plasticizer-free PVB films are, for example, Movital, available from Kuraray. ®The interlayer film. Particularly preferably, the viscous interlayer film has a plasticizer content of less than 5%, preferably less than 1%, and is particularly free of plasticizer; and if present, further viscous interlayer films preferably each have a plasticizer content of at least 15 wt%. Alternatively, the viscous interlayer film has a plasticizer content of at least 15 wt%, and if present, at least one further viscous interlayer film has a plasticizer content of less than 5%, preferably less than 1%, and is particularly free of plasticizer. Due to the absence of plasticizer, the interlayer film has better dimensional stability during lamination, which allows the patterning of light-scattering elements to be maintained with higher quality. Furthermore, the plasticizer-free viscous interlayer film has a smoother surface with lower roughness, which allows the low-refractive-index layer to be applied with a more uniform layer thickness. A further advantage is that little or no plasticizer can diffuse out, which can affect the quality of the sandwich panel, especially if the sandwich panel has one or more particularly unsealed functional elements.

[0038] According to the invention, the adhesive interlayer has a layer thickness of 1 μm to 100 μm, particularly preferably 10 μm to 75 μm, and especially 25 μm to 50 μm. The thinner layer thickness allows for the use of films with lower plasticizer contents. This makes the adhesive interlayer more suitable for depositing low-refractive-index layers thereon. If the adhesive interlayer is thicker, this may mean that the sandwich panel must be thicker, as other layers with potentially higher plasticizer contents must also be correspondingly thicker. This may affect the stability of the sandwich panel. The reduced thickness also saves material costs. If a further adhesive interlayer is present, each further adhesive interlayer has a layer thickness of 1 μm to 1000 μm, particularly preferably 1 μm to 100 μm, very particularly preferably 10 μm to 75 μm, and especially 25 μm to 50 μm. After the layers are laminated to form a sandwich panel, the thickness of the entire intermediate layer is preferably from 0.1 mm to 2 mm, particularly preferably from 0.25 mm to 1 mm, and typically 0.38 mm or 0.76 mm. In this context, the term "intermediate layer" refers to all layers and elements disposed between the inner and outer panels, including any functional elements, membranes, and other layers that may be present.

[0039] The viscous interlayer preferably has a refractive index that deviates from the refractive index of the inner panel by less than 0.1, particularly preferably less than 0.08, very particularly preferably less than 0.05, and especially less than 0.03. If the viscous interlayer is further arranged between the inner panel and the low-refractive-index layer, it preferably has a refractive index that deviates from the refractive index of the inner panel by less than 0.1, particularly preferably less than 0.08, very particularly preferably less than 0.05, and especially less than 0.03. The small difference in refractive index leads to improved light coupling into the inner panel and the surrounding interlayer. With a small difference in refractive index between adjacent layers, most of the coupled light does not undergo total internal reflection between adjacent layers, but propagates within the adjacent layers as if they constitute a continuous medium. In other words, most of the light coupled into the sandwich panel according to the invention propagates through all the viscous interlayers and the inner panel arranged between the inner surface of the inner panel and the low-refractive-index layer. Therefore, total internal reflection occurs primarily at the interfaces between the inlay and the inner surface, between the inlay and the low-refractive-index layer, or (further) at the interface between the viscous interlayer and the low-refractive-index layer.

[0040] According to the invention, a low-refractive-index layer is applied to either the inner or outer surface of the adhesive interlayer. If the low-refractive-index layer is applied to the outer surface of the adhesive interlayer, the adhesive interlayer is also intended to serve as a light-guiding medium to guide some of the light coupled into the inner panel of the sandwich panel. If the low-refractive-index layer is applied to the inner surface of the adhesive interlayer, the low-refractive-index layer can preferably be in direct spatial contact with the outer surface of the inner panel. Therefore, the low-refractive-index layer is disposed between the inner panel and the adhesive interlayer, and nothing is disposed between the inner panel and the low-refractive-index layer except for any possible light-scattering elements. This means that the light coupled into the inner panel is coupled into the inner panel primarily due to the significant difference in refractive index. In this case, the adhesive interlayer preferably does not need to be light-guiding; for example, it can be colored, which reduces material costs. Alternatively, and regardless of whether the low-refractive-index layer is disposed on the inner or outer surface of the adhesive interlayer, a further adhesive interlayer can be disposed between the adhesive interlayer and the inner panel.

[0041] In a preferred embodiment of the invention, a low-refractive-index layer is applied to the inner surface of the adhesive interlayer, and at least two further adhesive interlayers, preferably exactly two further adhesive interlayers, are arranged between the interlayer and the inner panel. Preferably, one of the two further adhesive interlayers is plasticizer-free; particularly preferably, the further adhesive interlayer closer to the inner panel is plasticizer-free. In particular, a light-scattering element is arranged between the two further adhesive interlayers. This has the advantage that the light-scattering element is arranged within the sandwich panel without contacting the low-refractive-index layer or the inner panel, which improves the stability and quality of the sandwich panel.

[0042] The low-refractive-index layer preferably has a refractive index of up to 1.50, particularly preferably up to 1.45, and especially up to 1.40. The lower the refractive index, the smaller the critical angle at which total internal reflection can occur. In other words, less light is lost through a layer with a low refractive index compared to through a layer with a high refractive index; conversely, total internal reflection occurs at the interface even at small incident angles.

[0043] In a preferred embodiment of the invention, not just one low-refractive-index layer is applied to the viscous interlayer, but at least two, preferably at least three, low-refractive-index layers are applied. Multiple low-refractive-index layers are applied in a stacked manner to the inner or outer surface of the viscous interlayer. This improves the uniformity of the low-refractive-index layers, which reduces light loss through the low-refractive-index layers.

[0044] The low-refractive-index layer can be an organic, cross-linked, or thermoplastic polymer, or alternatively, a mineral layer.

[0045] In a preferred embodiment of the invention, the low refractive index layer is formed as a paint layer, which can be obtained from a photocrosslinked resin (optionally mixed with a photoinitiator). Alternatively, the resin can also be thermally crosslinked. For example, it can be based on a two-component mixture. A layer of crosslinked resin is deposited on a viscous interlayer.

[0046] Specifically, the low-refractive-index layer comprises or is composed of a cross-linked polymer matrix having a refractive index of up to 1.42, preferably up to 1.40, and particularly up to 1.3, wherein the matrix is ​​preferably formed of a polyacrylate-based polymer, particularly preferably based on a fluorinated polyacrylate. The refractive index of the low-refractive-index layer can be reduced by fluorination. Using polyacrylate as the material for the low-refractive-index layer is advantageous because acrylate compounds can be efficiently cross-linked via photopolymerization, which simplifies the preparation of the low-refractive-index layer. Specifically, the polymer matrix is ​​based on urethane acrylates, fluorourethane acrylates, or fluorosilicate acrylates. Alternatively, the polymer matrix may also be based on silicone, polydimethylsiloxane, epoxy polymers, polyepoxides, polyurethanes, polyvinyl acetate, or polyesters. Preferably, the low-refractive-index layer does not contain any free silicone or silicon compounds (a source of surface contamination), so any silicone or silicon compounds present are part of the polymer matrix and are not removed from the low-refractive-index layer, for example, during degassing during lamination.

[0047] For the purposes of this invention, "polyacrylate" refers to a polymer containing repeating units of acrylic acid compounds, whose monomers therefore belong to the acrylate class. The repeating units may be substituted or unsubstituted within permissible valence states. Polyacrylates can be homopolymers or copolymers, meaning they can consist of only one monomer or multiple monomers of different types. Specifically, polyacrylate refers to polymers such as polymethyl methacrylate, polyvinyl acrylate, polypropyl methacrylate, polyvinyl methacrylate, polyethyl methacrylate, or polypropyl methacrylate. Polyacrylates may also refer to mixtures of these polymers.

[0048] For the purposes of this invention, "epoxy polymer" refers to a polymer containing an epoxy compound. The epoxy polymer preferably comprises one or more components selected from the group consisting of bisphenol A epoxy resin, halogenated phenolic epoxy resin, phenolic epoxy resin, alicyclic epoxy resin, and bisphenol S epoxy resin, particularly preferably in a proportion of at least 1% by weight, and especially at least 5% by weight.

[0049] The low refractive index layer can be, in particular, a coating applied to a viscous interlayer: • Flow coating, • Dipping, • Screen printing, • Digital printing, or • Inkjet printing.

[0050] The application of the low-refractive-index layer is specifically performed via spin coating, film stretching (film traction machine), curtain coating or slot coating, Mayer bar printing or gravure printing. The low-refractive-index layer is preferably applied as a UV-photocrosslinking substrate and subsequently polymerized using UV irradiation. Alternatively, it is also possible to apply two components that can react spontaneously (exothermic reaction) or react with each other under thermal influence (endothermic reaction). Thus, it is a two-component formulation that crosslinks to form a polymer via a chemical reaction. Crosslinking via UV irradiation is preferred because it is faster and the process is more cost-effective / compact compared to chemical reactions. Specifically, components polymerized under UVA irradiation (wavelength range of 315 nm to 380 nm) can be used.

[0051] In a preferred embodiment, the low-refractive-index layer comprises a polymer that can be prepared by photopolymerization, particularly preferably initiated by UV irradiation. The low-refractive-index layer is preferably based on a polyacrylate (e.g., a polyurethane acrylate resin) or a silicone compound.

[0052] The low refractive index layer preferably comprises (nano)pores and / or (nano) particles having a refractive index of less than or equal to 1.3. The pores and / or particles are preferably hollow and have a diameter of up to 300 nm, or particularly up to 100 nm. Particularly preferably, the low refractive index layer comprises hollow silica nanoparticles. Preferably, the optical isolation coating is free of free silicone and volatile silicon compounds (surface contaminants). The low refractive index layer preferably has up to 60% by volume, particularly preferably up to 50% by volume, very particularly preferably up to 40% by volume, and particularly up to 30% by volume, of (nano)pores and / or (nano) particles having a refractive index of less than or equal to 1.3.

[0053] In a particularly preferred embodiment of the invention, the low refractive index layer comprises a polyacrylate polymer matrix, wherein silica-based particles are embedded in the polymer matrix. Specifically, the low refractive index layer is composed of a polyacrylate polymer matrix, wherein silica-based particles are embedded in the polymer matrix. This allows for the efficient achievement of a refractive index less than 1.4.

[0054] In a further embodiment of the invention, the low refractive index layer is formed based on a mineral layer. Preferably, the low refractive index layer is composed of a mineral layer. In particular, the low refractive index layer is a sol-gel layer based on porous silica, or a layer based on an oxide (preferably silica) deposited on a viscous interlayer by physical vapor deposition (PVD) (such as magnetron sputtering). The low refractive index layer, particularly if it is primarily composed of silica, may contain dopants, such as aluminum dopants. If the low refractive index layer is formed based on porous silica, the pores of the silica preferably have an average pore size of 10 nm to 200 nm, particularly preferably 30 nm to 200 nm. In addition to the preferred pore size, or independently of the preferred pore size, the porous silica preferably has a porosity of 40% to 85%, very particularly preferably 50% to 74%. Porosity represents the proportion of pore volume to the total volume of the porous silica. A particularly suitable and uniformly distributed refractive index is obtained in these regions.

[0055] If the low refractive index layer is formed based on a mineral layer, then apart from any impurities or dopants, the layer is mainly composed of a mineral layer, and in particular, is primarily composed of this material.

[0056] The low-refractive-index layer comprises at least one single layer, but may also comprise multiple layers, such as two, three, or four single layers. Specifically, the low-refractive-index layer consists of exactly one layer. If the low-refractive-index layer comprises multiple individual layers, these individual layers may be formed differently. The layer thickness of the low-refractive-index layer is preferably at most 1 mm, particularly preferably less than 50 µm, and especially less than 400 nm. If the low-refractive-index layer comprises multiple layers, the specified layer thickness refers to the sum of the layer thicknesses of all the individual layers of the low-refractive-index layer.

[0057] If the low-refractive-index layer is a mineral layer (e.g., formed based on SiO2), it can be applied by physical vapor deposition or chemical vapor deposition (i.e., PVD or CVD coatings, PVD: Physical Vapor Deposition, CVD: Chemical Vapor Deposition), or, for example, by a sol-gel process. Such coatings can be produced with particularly high visual quality and particularly thin thickness. If more than one low-refractive-index layer is applied to the viscous interlayer, multiple individual layers (if present) are applied sequentially, i.e., one after another. Applying these layers by a sol-gel process is known to those skilled in the art and can be obtained, for example, from WO2021209201A1. The volumetric pore size of porous silica can be confined and controlled by fabricating it using a sol-gel process.

[0058] PVD coatings can be applied by cathode sputtering (sputtering), particularly by magnetic field-assisted cathode sputtering (magnetron sputtering). Preferably, the low-refractive-index layer (if it is a mineral layer, such as SiO2) is applied by magnetron sputtering. Magnetron sputtering allows for the efficient production of uniform coatings several nanometers thick.

[0059] If a low-refractive-index layer is applied by chemical vapor deposition, this is preferably performed by plasma-enhanced chemical vapor deposition (PECVD); specifically, this preparation is performed at atmospheric pressure (APCVD). Compared to other methods, plasma-enhanced chemical vapor deposition offers advantages in layer application speed and simultaneously high uniformity. In particular, this preparation allows for the uniform and efficient application of silicon oxide onto the substrate.

[0060] Preferably, the low-refractive-index layer extends over at least 80%, particularly preferably at least 90%, of the main surface of the sandwich panel. Specifically, the low-refractive-index layer extends over the entire main surface of the sandwich panel. In a very advantageous embodiment of the invention, the low-refractive-index layer extends over the entire main surface of the sandwich panel, except in the frame-like peripheral edge regions of the sandwich panel. In a top view of the sandwich panel, the low-refractive-index layer is surrounded by areas where no low-refractive-index layer is provided. The uncoated edge regions protect the low-refractive-index layer from moisture that may enter through the edge surfaces of the sandwich panel.

[0061] The adhesive interlayer preferably extends over the entire main surface of the sandwich panel. However, it is also possible that the adhesive interlayer extends only over at least 80%, preferably at least 90%, of the main surface of the sandwich panel. In particular, the adhesive interlayer extends over the entire main surface of the sandwich panel, except for the peripheral edge areas. If the adhesive interlayer does not extend over the entire main surface of the sandwich panel, it is preferable to cover the portion of the sandwich panel over which the adhesive interlayer does not extend with an auxiliary interlayer, such that, together, the adhesive interlayer and the auxiliary interlayer extend over the entire main surface of the sandwich panel. The auxiliary interlayer and the adhesive interlayer have an overlap area preferably less than 10 cm², particularly preferably less than 1 cm². In particular, the auxiliary interlayer and the adhesive interlayer do not overlap at all. This avoids local thickness differences in the sandwich panel. The auxiliary interlayer may be made of the same material as the adhesive interlayer, or may be made of a different material, preferably the same material. The auxiliary interlayer preferably has a thickness equal to or greater than that of the adhesive interlayer. The low-refractive-index layer is preferably not also applied to the auxiliary interlayer. Using an adhesive interlayer framed by the auxiliary interlayer simplifies the application of the low-refractive-index layer to the interlayer, as the low-refractive-index layer can be coated across the entire surface while still being adequately protected against moisture ingress into the interlayer panel via the edge surfaces. This allows for coating processes such as magnetic field-assisted cathode sputtering (magnetron sputtering).

[0062] In a particularly preferred embodiment of the invention, the adhesive interlayer extends over the entire main surface of the sandwich panel, except in the peripheral edge regions of the sandwich panel. Furthermore, a further adhesive interlayer is arranged substantially concurrently with the adhesive interlayer between the sandwich panel and the adhesive interlayer. An auxiliary interlayer is arranged around the adhesive interlayer and the further adhesive interlayer. The auxiliary interlayer is arranged around the adhesive interlayer and the further adhesive interlayer like a frame. The auxiliary and adhesive interlayers are arranged such that, when viewed together, they extend over the entire main surface of the sandwich panel. The auxiliary interlayer preferably has a thickness equal to or greater than the combined thickness of the frame-type adhesive interlayer and the frame-type further interlayer. A low-refractive-index layer is preferably applied to the outer surface of the adhesive interlayer. In this way, the low-refractive-index layer is optimally protected from harmful effects that may penetrate via the edge surfaces of the sandwich panel.

[0063] In a further preferred embodiment, an intermediate panel is disposed between the adhesive interlayer and the outer panel, wherein a thermoplastic interlayer (e.g., the adhesive interlayer) is disposed between the outer panel and the intermediate panel. Thus, the sandwich panel has three panels, with the adhesive interlayer disposed between each panel, connecting the inner panel to the intermediate panel, and connecting the intermediate panel to the outer panel. Preferably, the inner panel and the adhesive interlayer disposed between the inner panel and the intermediate panel do not extend across the entire surface of the intermediate panel, such that the area of ​​the outer panel and the intermediate panel is, in each case, larger than the area of ​​the inner panel, the adhesive interlayer, and all other layers or elements disposed between the inner panel and the intermediate panel. This simplifies light coupling into the inner panel via its peripheral side edge surfaces. The intermediate panel may be made of the same material as the inner panel and / or the outer panel, or it may be made of a different material. The thickness of the intermediate panel can vary considerably. Preferably, the middle panel has a thickness ranging from 0.8 mm to 5 mm, preferably from 1.4 mm to 2.5 mm, for example, a standard thickness of 1.6 mm or 2.1 mm.

[0064] In the context of this invention, the refractive index is defined in all cases relative to a wavelength of 550 nm. Methods for determining the refractive index are known to those skilled in the art. The refractive index defined within the scope of this invention can be determined, for example, by an ellipsometer, where a commercially available ellipsometer can be used. If the refractive index relates to a coating having multiple layers in a layer stack, then the refractive index refers to the effective refractive index across all layers. The effective refractive index describes the average optical density of the medium in which light waves propagate / impact. The effective refractive index takes into account the different refractive indices of the individual layers of the layer stack. Unless otherwise stated, layer thickness or descriptions of thickness refer to the geometric thickness of the layer.

[0065] The meaning of the specified layer thickness and how it is measured will be clear to those skilled in the art. Regarding the viscous interlayer film according to the invention, the indicated layer thickness preferably indicates a substantially constant thickness over its entire range, where typical error tolerances must be taken into account. Therefore, depending on the location, the layer thickness may deviate from the average layer thickness by ±5%, preferably ±3%, and particularly preferably ±1%.

[0066] Methods for measuring the thickness of layers (including films or coatings) are known to those skilled in the art. Coatings can be determined using common methods for determining the thickness of thin layers, such as spectral reflectance, confocal microscopy, white light interferometry, or ellipsometric spectroscopy. These methods allow for non-destructive measurements, and the corresponding measuring equipment is commercially available. Ellipsomers are commercially available, for example, from Sentech. White light interferometry, profilometry (e.g., confocal profilometry), or ellipsometric spectroscopy is preferred. For thicker layers in the micrometer range, such as viscous interlayers, the layer thickness can be determined, for example, using an outside micrometer or optical microscopy.

[0067] The inner panel preferably has a light transmittance of at least 70%, particularly preferably at least 80%, and most particularly preferably at least 90% (according to ISO 9050:2003). If a low-refractive-index layer is applied to the outer surface, the adhesive interlayer preferably has a light transmittance of at least 70%, particularly preferably at least 80%, and most particularly preferably at least 90% (according to ISO 9050:2003). If further adhesive interlayers are disposed between the inner panel and the low-refractive-index layer, these further adhesive interlayers preferably have a light transmittance of at least 70%, particularly preferably at least 80%, and most particularly preferably at least 90% (according to ISO 9050:2003).

[0068] Within the meaning of this invention, "transparent" means a light transmittance of at least 70%, preferably at least 80%, and particularly preferably at least 90% (according to ISO 9050:2003). Within the meaning of this invention, "semi-transparent" means a light transmittance of at most 70%, preferably at most 50%, and particularly preferably at most 30% (according to ISO 9050:2003). Within the meaning of this invention, "opaque" means a light transmittance of less than 30%, preferably less than 20%, particularly preferably less than 5%, and particularly less than 0.1% (according to ISO 9050:2003).

[0069] The sandwich panel preferably has an opaque, shielded area, which is preferably not transparent. This shielded area is preferably arranged along the perimeter of the edge region of the sandwich panel and surrounds the central transparent area like a frame. This is particularly common for vehicle panels. The shielded area is particularly formed by opaque elements, such as by a milky white overprint or an opaque portion of the intermediate layer. The shielded area is particularly preferably formed by an opaque overprint located on the inner surface of the outer panel. This overprint is typically made of enamel, containing glass powder and black pigment, applied using a screen printing method, and subsequently burned into the surface.

[0070] The outer and inner panels are preferably made of clear glass, particularly soda-lime glass commonly used for window panels. However, in principle, glass panels can also be made of other types of glass (e.g., borosilicate glass, quartz glass, aluminosilicate glass) or clear plastics (e.g., polymethyl methacrylate or polycarbonate). The thickness of the outer and inner panels can vary considerably. Preferably, panels with a thickness ranging from 0.8 mm to 5 mm, preferably from 1.4 mm to 2.5 mm, such as those with standard thicknesses of 1.6 mm or 2.1 mm, are used. The outer and inner panels can be independently untempered, semi-tempered, or tempered. If at least one panel is to be tempered, it can be thermally or chemically tempered. According to an advantageous embodiment of the invention, the outer panel is tinted. This is particularly useful if the laminated panel is used as a vehicle canopy panel.

[0071] The outer panel, inner panel, and sandwich panel can have any three-dimensional shape. Preferably, the inner and outer panels have no shaded areas, allowing them to be efficiently coated by cathode sputtering. The inner panel, outer panel, and therefore the sandwich panel are preferably flat, or slightly or strongly curved in one or more spatial directions. Further panels are preferably curved in the projection area to the same shape as the inner panel.

[0072] In a further preferred embodiment of the invention, an optically controllable functional element is arranged between a low-refractive-index layer and an outer panel. The functional element is particularly preferably a PDLC (polymer-dispersed liquid crystal) functional element with an active layer, which is essentially responsible for the optical properties. The active layer of the PDLC functional element contains liquid crystal embedded in a polymer matrix. If no voltage is applied to the surface electrode, the liquid crystal will align in a disordered manner, resulting in strong scattering of light through the active layer. If a voltage is applied to the planar electrode, the liquid crystal in the second region of the active layer and in any further regions of the active layer will align in the same direction, increasing the transmittance through the active layer. Alternatively, it is also possible to use functional elements that are transparent when no voltage is applied (zero volts) but strongly scatter when a voltage is applied, particularly PDLC functional elements.

[0073] Alternatively, the optically controllable functional element may also be an electrochromic functional element or an SPD (suspended particle device) functional element. The aforementioned controllable functional elements and their operation methods are known to those skilled in the art, and therefore need not be described in detail here.

[0074] In a particularly preferred embodiment, the functional element is a PDLC functional element, and at least one adhesive interlayer (preferably, the adhesive interlayer) is a plasticizer-free film. Specifically, at least one of the plasticizer-free adhesive interlayers is in direct spatial contact with the PDLC functional element. This is particularly advantageous because the active layer is very sensitive to plasticizers, which can diffuse out of the interlayer and enter the active layer via the edge surface of the active layer. Therefore, it is advantageous to maintain a low plasticizer concentration or avoid the presence of plasticizers in the vicinity. The functional element can also be more securely arranged within the interlayer because the plasticizer-free film provides better stability when the layers are stacked.

[0075] In a further preferred embodiment of the invention, at least one further adhesive interlayer is disposed between the adhesive interlayer and the outer panel. Particularly preferably, two further adhesive interlayers are disposed between the adhesive interlayer and the outer panel, and the functional element (preferably a PDLC functional element) is disposed between these two adhesive interlayers. Specifically, a third further adhesive interlayer is disposed between the adhesive interlayer and the outer panel, and is arranged circumferentially around the functional element. In other words, the functional element, more precisely, its side surfaces, are surrounded circumferentially by the third further adhesive interlayer. The third further adhesive interlayer is frame-shaped, having recesses into which the functional element is inserted. The third further adhesive interlayer disposed between the adhesive interlayer and the outer panel can be formed from a thermoplastic film in which recesses have been cut. Alternatively, the third adhesive interlayer can also consist of multiple film portions surrounding the functional element.

[0076] The invention also extends to a luminescent glass window element comprising a sandwich panel according to the invention and a light source. The light source is arranged such that light from the light source can at least partially, and preferably substantially, couple into the sandwich panel.

[0077] In an advantageous embodiment, the light source is arranged in a shielded area of ​​the sandwich panel, and light is coupled into the shielded area. Therefore, the light source is invisible from the external environment, at least to the observer.

[0078] The insert can be designed such that light from a light source enters the insert via an edge surface. Alternatively, the light source may be positioned within a recess in the insert (e.g., in a feedthrough), such that light is incident on the insert via a side edge surface of the recess and thus coupled into it. Methods of coupling light into the insert via the edge surface of a light guide or via a recess are generally known to those skilled in the art and are disclosed, for example, in WO2010049638A1, US20120104789A1, and WO2018149568A1.

[0079] In a preferred embodiment, the inlay panel has an optical coupling device in the form of a reflective structure with a reflective surface, preferably a microprism structure. The reflective structure is preferably formed on or fastened to the outer surface of the inlay panel. The reflective surface has multiple portions inclined to the outer surface and is configured such that light incident on and passing through the inlay panel is reflected at the reflective surface and at least partially coupled back into the inlay panel, and optionally also coupled back into the adhesive interlayer and / or further interlayer. Light from the light source is reflected into the inlay panel through the reflective surface and coupled into the inlay panel at a coupling angle suitable to allow at least partially (at least some of the coupled light) to propagate in the inlay panel through total internal reflection at the inner surface and at the interface with the low-refractive-index layer, causing the light to reflect back and forth between the inner surface of the inlay panel and the low-refractive-index layer. Light from the light source preferably enters the inlay panel via the inner surface of the inlay panel and subsequently strikes the reflective structure, allowing it to couple into the inlay panel. More precisely, - The light from the light source passes through the light guide and strikes the outer surface. If a reflective structure is formed in the outer surface, the light is reflected at the outer surface. The reflective surface of the reflective structure is a part of the outer surface, and the light is reflected by this part of the surface. - Alternatively, the light from the light source passes through the inner panel, exits the inner panel again via the outer surface, and is reflected on the reflective surface of the reflective structure if the reflective structure is fastened to the outer surface; preferably, the light exiting the inner panel passes through the reflective structure and is reflected on its surface opposite to the inner panel, which forms a reflective surface.

[0080] In an alternative embodiment, the adhesive interlayer (in this example, having a low-refractive-index layer on its outer surface) or a further adhesive interlayer disposed between the inlay and the adhesive interlayer has an optical coupling device, which is in the form of a reflective structure with a reflective surface, preferably a microprism structure. The reflective structure is applied to the outer surface of the adhesive interlayer or the further adhesive interlayer. The reflective surface has multiple portions inclined to the outer surface and is configured such that light that has been incident on and passed through the adhesive interlayer and / or the further adhesive interlayer is reflected at the reflective surface and at least partially coupled into the adhesive interlayer and / or the further adhesive interlayer and the inlay. Light from the light source is reflected by the reflective surface into the adhesive interlayer or the further interlayer and coupled therein at a coupling angle suitable such that the coupled light at least partially (at least some of the coupled light) propagates in the inlay and the adhesive interlayer and / or the further interlayer through total internal reflection. The light from the light source preferably enters the sandwich panel through the inner surface of the inner panel, is transmitted through the inner panel, exits at the outer surface of the inner panel, enters the further adhesive interlayer through the inner surface of the further adhesive interlayer, or enters the further adhesive interlayer through the adhesive interlayer, and then strikes the reflective structure, allowing it to couple into the inner panel. Alternatively, the light preferably enters the sandwich panel through the inner surface of the inner panel, is transmitted through the inner panel, exits at the outer surface of the inner panel, enters the further adhesive interlayer through the inner surface of the further adhesive interlayer, is transmitted through the further adhesive interlayer, exits at the outer surface of the further adhesive interlayer, enters at the outer surface of the adhesive interlayer, and then strikes the reflective structure, allowing it to couple into the sandwich panel.

[0081] The reflective surface is preferably provided with a reflective coating. The reflective coating includes at least one reflective layer based on a metal or metal alloy. This improves the reflectivity of the reflective surface.

[0082] The reflective structure is preferably a microprism film. The microprism film is attached, for example, adhesively bonded to the outer surface of the inlay, the outer surface of an adhesive interlayer, or the outer surface of a further adhesive interlayer, preferably the outer surface of the inlay. The reflective surface of the reflective structure is preferably arranged facing away from the inlay. The microprism film is transparent. Light from the light source is transmitted through the microprism film and strikes its reflective surface, where it is reflected and then passes through the microprism film again, re-entering the inlay, adhesive interlayer, or further adhesive interlayer via the outer surface.

[0083] The microprism film is a flexible polymer film, particularly a foil-like polymer film, having a smooth surface facing and specifically arranged on the inlay panel, and a structured surface facing away from the inlay panel. The structured surface is in the form of a planar arrangement of multiple prisms having dimensions in the micrometer range, wherein the prism surfaces form inclined portions of the reflective surface. The microprisms specifically function as reflective prisms, reflecting light striking them in a direction that depends on the tilt angle of the prism surface and the angle of incidence of the light. The microprism film is commercially available and can be purchased, or can be specially produced during the production of the glass window element according to the invention or the sandwich panel according to the invention. The edge length of an individual microprism is preferably from 10 µm to 250 µm, particularly preferably from 20 µm to 100 µm, for example, about 30 µm.

[0084] Microprism films can be formed in multiple layers. For example, microprism films with a substrate layer are commonly used, such as a polyethylene terephthalate (PET) substrate layer on which the microprisms are formed by UV-cured polyacrylate.

[0085] The microprism film is transparent and preferably has a transmittance of at least 70%, particularly preferably at least 80%, and most particularly preferably at least 90% relative to the light source (according to ISO 9050:2003). To reduce reflection loss at the interface between the corresponding film or panel and the microprism film, it is advantageous to minimize the difference in refractive index between the panel, adhesive interlayer, or further adhesive interlayer and the microprism film. Preferably, the difference in refractive index is at most 0.02 (based on a 550 nm wavelength), particularly preferably at most 0.01. If the panel, adhesive interlayer, or further adhesive interlayer differs from the microprism film in its refractive index, the microprism film preferably has a higher refractive index than the film or panel to which it is applied, which is beneficial for high-yield optical coupling.

[0086] In principle, rigid microprism plates, i.e. rigid plastic plates with a planar arrangement of microprisms, can also be used as alternatives to flexible microprism films.

[0087] However, the reflective structure can also be formed directly on the outer surface of the insert, the outer surface of the adhesive interlayer, or the outer surface of a further adhesive interlayer, preferably on the outer surface of the insert. For this purpose, a portion of the outer surface is formed as a reflective surface. This is easier to achieve if the structure is formed within the insert, especially if the insert is a polymer layer, such as a plastic sheet or plate. Light from the light source is reflected directly at the outer surface and then reflected back. If the reflective surface with the reflective coating is designed to reflect only partially, some of the light will naturally exit the insert or the adhesive interlayer or further adhesive interlayer via the outer surface and will not be reflected.

[0088] According to the invention, the reflective surface of the reflective structure has portions inclined towards the inner surface of the inlay. This means that these portions are arranged not parallel to the inner surface, but at an angle greater than 0° to the inner surface. The portions have an angle between 0° and 90°, preferably 28° to 60° or 30° to 60°, most particularly preferably 30° to 50°, especially 40° to 50°, for example, about 45°. This refers to the absolute value of this particular angle. These portions can be inclined in different directions.

[0089] These parts are also preferably inclined toward each other. This means that adjacent parts are inclined toward each other, i.e., they are arranged not parallel to each other, but at an angle of 0° to 180° to each other.

[0090] The portions of the reflective surface are preferably substantially flat. The inclination of these portions of the reflective surface relative to the inner surface of the light guide determines the angle at which the reflected light is reflected back to the panel or film on which the structure is applied or integrated.

[0091] In a further preferred embodiment of the invention, an optical coupling device is disposed (preferably applied) on the inner surface of the inlay panel. The beam path of the light source is directed towards the optical coupling device, such that light from the light source can be at least partially coupled into the inlay panel and (optionally) the adjacent adhesive interlayer. The optical coupling device preferably couples light from the light source into the inlay panel and (optionally) the adjacent adhesive interlayer by scattering, reflection, refraction, or diffraction. The light source is preferably connected to the inlay panel via the optical coupling device. A collimator may be disposed between the light source and the optical coupling device, i.e., in the beam path of the light source.

[0092] The optical coupling device disposed on the inner surface of the inlay panel preferably has a transmittance of at least 20%, preferably at least 50%, particularly at least 70% (according to ISO 9050:2003).

[0093] In an advantageous embodiment, the optical coupling device is integrated into the inner surface of the panel, preferably by laser structuring, mechanical structuring (such as sandblasting), and / or etching (preferably chemical or physical etching). Flat, irregular surface structures are particularly suitable, as they result in diffuse light scattering upon illumination. Alternatively, linear or grid-like (e.g., cross-grid) structures can be introduced. Alternatively, the optical coupling agent can be printed onto the inner surface of the panel by inkjet printing or screen printing. Advantageously, the printing material contains particles suitable for scattering, refracting, diffracting, or reflecting light.

[0094] In another advantageous embodiment, the optical coupling device includes a transparent body, which is integrally attached to the inner surface of an inlay, for example, by an adhesive bonding agent. The transparent body preferably comprises or is constituted by a structured plastic film or sheet, for example, having light-scattering, light-refracting, light-diffusing, or light-reflecting particles. Alternatively, the transparent body preferably comprises or is constituted by a holographic film. The transparent body may also comprise or be constituted by a planar arrangement of microprisms, such as randomly or grid-like pyramids or linearly arranged steps (hereinafter also referred to as step prisms). The transparent body typically has a surface structure constituted by such microprisms. Such microprisms can advantageously be manufactured by machining (such as stamping or embossing), chemical etching, photolithography, or other transfer techniques.

[0095] Light propagates between the inner surface of the inlay and the low-refractive-index layer until it strikes the side edge surface of the inlay; or, if an adhesive interlayer is disposed between the low-refractive-index layer and the inlay, it strikes the side edge surface of the adhesive interlayer or, further, the side edge surface of the adhesive interlayer, and couples away there. Alternatively, light is incident on a light-scattering element that interrupts total internal reflection by light scattering, thereby coupling light away from the light guide via the element in question.

[0096] The glass window element is equipped with a light source suitable for coupling light into the sandwich panel. During operation, the light source emits visible light, i.e., electromagnetic radiation in the visible spectrum, particularly in the range of 380 nm to 780 nm. The light source may have one or more emission bands arranged in the visible spectrum and covering a portion of it. However, the light source may also have a wide emission band covering the entire visible spectrum. The emission bands, and therefore the color of the irradiated light, can be freely selected according to the requirements of the specific application.

[0097] The glass window element may have a single light source or multiple separate light sources whose light is coupled into the inlay, adhesive interlayer and / or further adhesive interlayer at different points.

[0098] The light sources having different emission wavelengths preferably include: a light source with a red emission color (particularly having an average emission wavelength of about 630 nm), a light source with a green emission color (particularly having an average emission wavelength of about 550 nm), and a light source with a blue emission color (particularly having an average emission wavelength of about 473 nm). The light from these light sources (RGB) is superimposed to form white light, such that the white light can be coupled into the light guide and selectively coupled into the viscous interlayer and / or further viscous interlayer.

[0099] The light source preferably includes at least one light-emitting diode (LED). The light source can be a single LED, but is preferably an arrangement of multiple LEDs. This arrangement is preferably mounted within the same housing, for example, as a linear arrangement where the LEDs are arranged in a straight line. The electroluminescent material of the LED 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).

[0100] Optionally, a collimator may be arranged between the light source and the reflective structure, wherein the collimator is located in the beam path of the light source. The collimator is preferably arranged between the inner surfaces of the light source and the light guide, and particularly preferably between the light source and the interlayer, such that light is incident on the interlayer or light guide via the collimator. The collimator generates a beam from the typically divergent beam of the light source, preferably with substantially parallel beam paths, but at least with less divergence (i.e., more concentrated beam paths). Therefore, the beam cone of the light source is narrowed by the collimator. This has the advantage that the entire beam is incident on the interlayer at the same angle of incidence, particularly at an angle that, combined with the reflective properties of the reflective structure, ensures that most of the light is coupled into the interlayer and optionally into the viscous interlayer and / or further viscous interlayer, resulting in total internal reflection. Therefore, the light output is optimized.

[0101] In its simplest case, the collimator is a converging lens, and the light source is preferably positioned at its focal point. The collimator can be formed, for example, from glass or a transparent plastic material, particularly polycarbonate (PC) or polymethyl methacrylate (PMMA). The collimator is preferably attached, for example, adhesively bonded to the inner surface of an insert. If the light source is formed as an arrangement of multiple light-emitting diodes (LEDs), a separate collimator can be provided for each LED. However, it is preferable to use the same collimator for the entire LED arrangement. In the case of a linear LED arrangement, a rod-shaped collimator, for example, with a length at least corresponding to the length of the LED arrangement, can be used.

[0102] The sandwich panel according to the present invention can be prepared by a method comprising the following steps: (A) Provides a layer stack comprising an outer panel, an inner panel, at least one adhesive interlayer disposed between the inner panel and the outer panel, and a low refractive index layer applied to the adhesive interlayer. (B) The layers are stacked and laminated to form a sandwich panel.

[0103] Sandwich panels can be produced using methods known per se for lamination, such as autoclave processes, vacuum bag processes, vacuum ring processes, calendering processes, vacuum laminators, or combinations thereof. Outer and inner panels are often joined under heating, vacuum, and / or pressure.

[0104] The sandwich panel according to the invention can be used as a window panel for vehicles. A particularly preferred application is as a roof panel for illuminating the interior of a vehicle. In principle, the vehicle can be any land vehicle, ship, or aircraft, and is preferably a passenger car, a heavy cargo vehicle, or a rail vehicle. The sandwich panel can also be used in buildings, for example as a window panel, glass curtain wall, or glass door in exterior or interior areas, particularly as a window panel for buildings or interiors. The sandwich panel can also be used as a component of furniture, appliances, furnishings, or as a furniture article. Attached Figure Description

[0105] The present invention will be described in more detail with reference to the accompanying drawings and embodiments. The drawings are schematic diagrams and are not to scale. The drawings do not limit the invention in any way. In the drawings: Figure 1 Through Figure 3 The cross-section of the sandwich panel, Figure 2 By according to Figure 3 The cross-section of the luminescent glass window element. Figure 3 This is a top view of an embodiment of a luminescent glass window element according to the present invention, the luminescent glass window element including an embodiment of a sandwich panel according to the present invention. Figure 4-20 A further embodiment of the sandwich panel according to the invention is shown in cross-sectional view, and Figure 21-27 A further embodiment of the luminescent glass window element according to the present invention is shown in cross-sectional view. Detailed Implementation

[0106] Figure 1 A first embodiment of the sandwich panel 100 according to the present invention is shown in cross-sectional view. Figure 2 A cross-sectional view of a first embodiment of a luminescent glass window element 101 according to the present invention is shown, the luminescent glass window element 101 comprising... Figure 1 The interlayer panel 100 in the middle. Figure 3 Showing Figure 1 A top view of the inner surface IV of the sandwich panel 100, or Figure 2 A top view of the luminous glass window element 101, wherein Figure 1 and Figure 2 The cross-section of the cross-sectional diagram in Figure 3 The cross-section line X-X' indicates the direction.

[0107] The sandwich panel 100 is, for example, a roof panel for a vehicle (particularly a passenger car). For simplicity, it is shown as flat, but such vehicle roof panels are typically curved. The sandwich panel 100 is structurally formed by an outer panel 1, an inner panel 2, and an intermediate layer 3, with the outer panel 1 and inner panel 2 connected to each other via the intermediate layer 3. The outer panel 1 and inner panel 2 are, for example, made of soda-lime glass. The outer panel 1 has a thickness of, for example, 2.1 mm. The inner panel 2 has a thickness of, for example, 2.05 mm. The intermediate layer 3 includes an adhesive interlayer 3.1, which is formed, for example, based on PVB with a thickness of, for example, 0.09 mm. The entire intermediate layer 3, having all the interlayers (individual films not shown here), has a thickness of, for example, 0.76 mm. The inner panel 2 is transparent, while the outer panel 1 and the adhesive interlayer 3.1 are colored to reduce the light transmittance of the sandwich panel 100 (e.g., below 15%), as is common for vehicle roof panels. Alternatively, the adhesive interlayer 3.1 may also be uncolored, i.e., transparent.

[0108] The outer panel 1 has an inner surface II facing the intermediate layer 3 and an outer surface I facing away from the intermediate layer 3. The inner panel 2 has an outer surface III facing the intermediate layer 3 and an inner surface IV facing away from the intermediate layer 3. The adhesive interlayer 3.1 has an inner surface ii facing the inner panel 2 and an outer surface i facing the outer panel 1. When installed in a vehicle, the inner surfaces II, IV, and ii face the interior of the vehicle, while when installed in a vehicle, the outer surfaces I, III, and i face the external environment.

[0109] A low-refractive-index layer 4 is applied to the inner surface ii of the adhesive interlayer 3.1. The low-refractive-index layer 4 extends over the entire inner surface ii of the adhesive interlayer 3.1. However, it is also possible that it extends only over a portion of the inner surface ii of the adhesive interlayer 3.1, such as the area of ​​the sandwich panel 100 intended for visibility (not shown here). Thus, the low-refractive-index layer 4 is arranged directly adjacent to the inner panel 2. For example, the low-refractive-index layer 4 has a refractive index of less than 1.4, while the inner panel 2 has a refractive index of 1.52. The low-refractive-index layer 4 is, for example, composed of a polymer matrix based on an acrylic compound, in which silica-based hollow particles are embedded.

[0110] Along its peripheral side edges, the interlayer panel 100 has a peripherally opaque edge region (masking region) where a black overlay 6 is applied to the inner surface II of the outer panel 1, preventing visibility through the interlayer panel 100. The interlayer panel 100 has four side edges that together form its peripheral side edges. The interlayer panel 100 has two optical coupling devices 7, each positioned near one of two opposite side edges of the interlayer panel 100. Each optical coupling device 7 may be, for example, a microprism film applied to the outer surface III of the inner panel 2 by, for example, a transparent adhesive. Each optical coupling device 7 is positioned entirely in front of the black overlay 6, such that it is not visible from the external environment when viewed through the interlayer panel 100. Preferably, a silver-based reflective layer is additionally applied to the microprism film of the optical coupling device 7.

[0111] The glass window element 101 also has two light sources 9, such as light-emitting diodes (LEDs). Figure 2 and Figure 3 Light source 9, for example, emits light 10, which has green emission and an average emission wavelength of 550 nm. Light source 9 is arranged on a portion of the inner surface IV of the inner panel 2. Collimators (not shown here) may optionally be arranged between each light source 9 and the inner panel 2. The collimator is a transparent optical component, for example made of polycarbonate, which acts as a converging lens and reduces the beam cone of the light source 9, ideally reducing it to a parallel beam path. The collimator is, for example, adhesively bonded to the inner surface IV of the inner panel 2, particularly via a layer of optically transparent adhesive (not shown). The collimator is only optional; in particular, it improves light output. As an alternative or supplement to the collimator, the light source 9 may, for example, be arranged in a housing (not shown) fastened to the inner surface IV of the inner panel 2.

[0112] In the top view of the inner surface IV of the interlayer panel 2, each light source 9 is arranged in front of the optical coupler 7. It should be understood that the two light sources 9 are not arranged in front of the same optical coupler 7. The two light sources 9 are therefore arranged near the opposite side edges of the interlayer panel 100.

[0113] Light 10 from the light source 9, emanating from the inner surface IV, passes through the inner panel 2 and strikes the outer surface III of the inner panel 2. An optical coupler 7 is positioned there and is illuminated by the light 10. The light 10 striking the optical coupler 7 is reflected at a certain angle (coupling angle α). Due to the tilted surface of the silver-coated microprism film, most of the light 10 emitted by the light source 9 is reflected at the coupling angle α. The remaining portion of the light 10 is not reflected at the coupling angle α.

[0114] The coupling angle α describes the change in the direction of light propagation (represented by a dashed arrow). The coupling angle α is the angle between the light vector incident on the microprism film (optical coupler 7) and the light vector emitted from the microprism film. The coupling angle α is between 90° and 180°, and for example, about 102°.

[0115] Surfaces III and IV of the inner panel 2 are each interfaces with the adjacent low-refractive-index layer 4 or the interior of the vehicle. At a wavelength of 550 nm from the light source 9, the refractive index of the inner panel 2 is 1.52 (soda-lime glass), the refractive index of the low-refractive-index layer 4 is, for example, 1.40, and the refractive index of air is approximately 1.00. For both surfaces III and IV, the critical angle for total internal reflection can be calculated: this angle is approximately 67° on the outer surface III (interface with the low-refractive-index layer 4) and approximately 41° on the inner surface IV (interface with air). The critical angle for total internal reflection is measured relative to the normal surface.

[0116] Light 10 from light source 9 enters the inner panel 2 via the inner surface IV, and then, after passing through the inner panel 2 and exiting via the outer surface III, strikes the optical coupler 7. There, light 10 is reflected. Light 10 then passes through the inner panel 2 and strikes the inner surface IV of the inner panel 2 primarily at an incident angle >67° (also measured relative to the normal surface). Since the incident angle is greater than the critical angle for total internal reflection (41°), light 10 is totally internally reflected, passes through the inner panel 2 again, and strikes the outer surface III at the same incident angle >67°. Here, the incident angle is also greater than the critical angle for total internal reflection, causing light 10 to be totally internally reflected again. Thus, light 10 is reflected back and forth, that is, between surfaces III and IV, causing it to propagate within the inner panel 2 until it strikes the light scattering element 5 or the side edge surface of the inner panel 2 and couples away from there. The low refractive index layer 4 lowers the critical angle, thereby allowing more light 10 to couple into the inner panel 2.

[0117] exist Figure 3 In the embodiment shown, light 10 from light source 9 strikes the inner surface IV at an incident angle of 0° (measured relative to the normal surface) before coupling. However, it is also possible that light 10 is not irradiated perpendicularly, but at an incident angle other than 0°. Alternatively, light source 9 may be arranged in a recess of the inner panel 2, or on a portion of the outer peripheral edge surface of the inner panel 2 (not shown here). In these cases, light 10 from light source 9 is directly coupled into the inner panel 2 via the edge surface (the outer peripheral edge surface of the inner panel 2 or the edge surface of its recess). In these cases, no additional optical coupling device 7 is required.

[0118] For reference Figures 4 to 26 These figures all show the sandwich panel 100 according to the present invention. Figures 4 to 20) or the glass window element 101 according to the present invention ( Figures 21 to 26 Different embodiments of the above are described. All embodiments share the common feature that the sandwich panel 100 is, for example, a vehicle roof panel, and the electronic functional element 8 is arranged between the outer panel 1 and the inner panel 2. The functional element 8 is, for example, a PDLC functional element; however, it can also be an SPD functional element or an electrochromic functional element. An adhesive interlayer 3.4 is arranged between the outer panel 1 and the functional element 8, and is hereinafter referred to as the fourth adhesive interlayer 3.4, in order to better distinguish it from the other adhesive interlayers 3.1, 3.2, 3.3, and 3.5 (particularly the adhesive interlayer 3.1 according to the invention). The fourth adhesive interlayer 3.4 adhesively bonds the functional element 8 to the inner surface II of the outer panel 1. Figures 1 to 3 As described, Figures 4 to 26 The sandwich panel 100 of the embodiment also has an opaque peripheral edge region (masking region) along the peripheral side edge, in which black overlay ink 6 is applied to the inner surface II of the outer panel 1, which prevents visibility through the sandwich panel 100.

[0119] exist Figures 4 to 26 In all embodiments, the functional element 8 does not extend over the entire surface of the interlayer panel 100, and in particular, it does not extend over the peripheral edge region of the interlayer panel 100. However, the edge region of the functional element 8 overlaps with the surrounding black overlay 6, and therefore the edge region of the functional element 8 is not visible from the external environment. An adhesive interlayer film 3.3 extends around the edge surface of the functional element 8 in a frame-like manner, and is hereinafter referred to as the third adhesive interlayer film 3.3, in order to better distinguish it from the other adhesive interlayer films 3.1, 3.2, 3.4, 3.5 (especially the adhesive interlayer film 3.1 according to the invention).

[0120] Functional element 8 has a thickness of, for example, 0.4 mm. The fourth adhesive interlayer 3.4 and the third adhesive interlayer 3.3 each or together have a thickness of, for example, 0.38 mm to 0.4 mm, and are formed, for example, based on PVB. The fourth adhesive interlayer 3.4 is, for example, colored to reduce the light transmittance of the sandwich panel 100 (e.g., below 15%), as is common for vehicle canopy windows; however, it may also be uncolored, i.e., transparent. Alternatively, the third adhesive interlayer 3.3 may, for example, have the same thickness as functional element 8 to avoid localized thickness differences in the sandwich panel 100. The outer panel 1 has a thickness of, for example, 2.1 mm. The inner panel 2 has a thickness of, for example, 2.05 mm. The outer panel 1 and the inner panel 2 are, for example, made of soda-lime glass. The low-refractive-index layer 4 in all embodiments has a refractive index of, for example, less than 1.4, while the inner panel 2 has a refractive index of 1.52. The low-refractive-index layer 4 is, for example, composed of a polymer matrix based on an acrylic compound, wherein hollow silica-based particles are embedded in the polymer matrix. Alternatively, the low-refractive-index layer 4 may also be made of porous silica. Figures 4 to 20 All embodiments also share the following common feature: the optical coupling device 7 or multiple optical coupling devices 7 are microprism films, which may optionally be provided with a reflective layer preferably based on silver. Each of the optical coupling devices 7 is completely arranged in front of the black overlay printing 6, such that the optical coupling device 7 is not visible from the external environment when viewed through the interlayer panel 100. The optical coupling device 7 is designed to be illuminated by visible light 10 from the light source 9, such that the light 10 can be coupled into the interlayer panel 100 through reflection at the optical coupling device 7. The operation mode of the (multiple) optical coupling devices 7 is similar to that of the optical coupling devices 7. Figures 1 to 3 Similar to what is described.

[0121] exist Figure 4In this sandwich panel 100, a low-refractive-index layer 4 is disposed between the inner panel 2 and the adhesive interlayer 3.1. The low-refractive-index layer 4 is applied to the inner surface ii of the adhesive interlayer 3.1, for example by liquid printing (inkjet printing) or, in the case of a mineral layer, by cathode sputtering. The sandwich panel 100 has two optical coupling devices 7, each disposed near one of the side edges of the sandwich panel 100, with the side edges facing each other. In a top view of the inner surface IV of the sandwich panel 100, the optical coupling devices 7 are completely disposed in front of the covering ink 6 and are therefore not visible from the external environment. The optical coupling devices 7 are attached to the outer surface III of the inner panel 2, for example, by a transparent adhesive. A second adhesive interlayer 3.2 is disposed between the adhesive interlayer 3.1 and the functional element 8. The adhesive interlayer 3.1 is, for example, a PVB-based film, preferably a PVB-based plasticizer-free film, having a layer thickness of, for example, 0.1 mm. The second adhesive interlayer 3.2 is formed, for example, based on a 0.38 mm thick PVB layer. The second adhesive interlayer 3.2 is colored, for example. Since the adhesive interlayer 3.1 does not contain plasticizers, the low refractive index layer 4 can be applied more uniformly to the interlayer 3.1. The interlayer 3 of the sandwich panel 100 is formed by all the adhesive interlayers 3.1, 3.2, 3.3, 3.4, the low refractive index layer 4, and the functional element 8.

[0122] The light scattering element 5 is integrated on the outer surface III of the inner panel 2, for example, as a roughening portion of the glass surface. Alternatively, the light scattering element 5 may be applied as an imprint on the outer surface III of the inner panel 2. It is also possible that the light scattering element 5 is applied as an imprint on the surface of the low-refractive-index layer 4 facing the inner panel 2. If the low-refractive-index layer 4 is not applied to the inner surface ii of the adhesive interlayer 3.1, the light scattering element 5 may also be applied to the inner surface ii of the adhesive interlayer 3.1. The low-refractive-index layer 4 extends over the entire surface of the sandwich panel 100, but may alternatively extend over a portion of the surface of the sandwich panel 100 (not shown here).

[0123] Figure 5 and Figure 6 The variants shown in the figure are basically corresponding to Figure 4 This is a variant of [the original text], so only the differences will be discussed here, and for other aspects please refer to [the original text]. Figure 4 Related descriptions. In Figure 5 In the middle, the low refractive index layer 4 is not applied to the inner surface ii of the viscous intermediate film 3.1, but to the outer surface i of the viscous intermediate film 3.1.

[0124] exist Figure 6In this embodiment, the adhesive interlayer 3.1 is arranged adjacent to the functional element 8, and the second adhesive interlayer 3.2 is arranged between the inner panel 2 and the adhesive interlayer 3.1. In this embodiment, the adhesive interlayer 3.1 is preferably colored, while the second adhesive interlayer 3.2 is preferably a transparent film, i.e., uncolored. If light is coupled into the inner panel 2 via the optical coupling device 7, most of the light propagates not only within the inner panel 2 but also within the second adhesive interlayer 3.2. Due to the small difference in refractive index between PVB and soda-lime glass, most of the light coupled into the inner panel 2 is not reflected at the interface between the inner panel 2 and the second adhesive interlayer 3.2. Instead, the light is transmitted through the second adhesive interlayer 3.2 and is totally internally reflected at the interface between the second adhesive interlayer 3.2 and the low-refractive-index layer 4. Therefore, the second adhesive interlayer 3.2 and the inner panel 2 essentially form a coherent light-guiding medium, wherein light is reflected back and forth between the interface with the low-refractive-index layer 4 and the interface with the interior of the vehicle until it couples away. The second viscous interlayer 3.2 may also alternatively be a plasticizer-free film based on PVB, preferably having a layer thickness of 0.05 mm.

[0125] Figure 7 The variants shown in the figure are basically corresponding to Figure 6 Variants in [the original text], therefore only the differences will be discussed here, and for other aspects please refer to [the original text]. Figure 6 Related descriptions or related Figure 4 Related descriptions. In Figure 7 In this process, the light scattering element 5 is applied to the surface of the second adhesive intermediate film 3.2 facing the functional element 8, for example, as an imprint. Alternatively, the light scattering element 5 may also be applied to the surface of the low refractive index layer 4 facing the inner panel 2.

[0126] Figure 8 The variants shown in the figure are basically corresponding to Figure 4 This is a variant of [the original text], so only the differences will be discussed here, and for other aspects please refer to [the original text]. Figure 4 Related descriptions. In Figure 8 In this process, light scattering element 5 is applied to the outer surface i of the viscous interlayer 3.1. A low-refractive-index layer 4 is also applied to the outer surface i of the viscous interlayer 3.1, but the light scattering element 5 is positioned between the viscous interlayer 3.1 and the low-refractive-index layer 4. Therefore, the low-refractive-index layer 4 is applied to the light scattering element 5 in some regions, but primarily to the viscous interlayer 3.1.

[0127] Figure 9 The variants shown in the figure are basically corresponding to Figure 6 This is a variant of [the original text], so only the differences will be discussed here, and for other aspects please refer to [the original text]. Figure 6 Related descriptions or related Figure 4 Related descriptions. In Figure 9In this embodiment, the low-refractive-index layer 4 is applied not to the inner surface ii of the adhesive interlayer 3.1, but to the outer surface i. Furthermore, a fifth adhesive interlayer 3.5, for example based on PVB, is disposed between the adhesive interlayer 3.1 and the functional element 8. The fifth adhesive interlayer 3.5 is, for example, colored. Light coupled into the insert 2 propagates not only within the insert 2 but also, to a large extent, via the adhesive interlayer 3.1 and the second adhesive interlayer 3.2. In this embodiment, the adhesive interlayer 3.1 is transparent, i.e., uncolored. For example, the second adhesive interlayer 3.2 is a plasticizer-free film based on PVB.

[0128] Figures 10 to 12 The variants shown in the figure are similar to Figure 9 The variants in [the original text] are basically the same, so only the differences will be discussed here, and for other aspects please refer to [the original text]. Figure 9 Related descriptions or Figure 4 and Figure 6 Related descriptions. In Figure 10 and Figure 11 In the middle, a low refractive index layer 4 is applied to the inner surface ii of the viscous intermediate film 3.1. Figure 10 and Figure 12 In this process, the light scattering element 5 is applied, for example, as an imprint to the surface (outer surface) of the second viscous intermediate film 3.2 facing the functional element 8. Figure 12 In the case of a variant, the light scattering element 5 may also alternatively be applied to the inner surface ii of the viscous intermediate film 3.1. Figure 11 In this process, the light scattering element 5 is applied, for example, as an imprint on the surface (inner surface) of the second adhesive intermediate film 3.2 facing the inner panel 2. Alternatively, the light scattering element 5 may also be applied to the outer surface III of the inner panel 2, or to the low refractive index layer 4 (here applied to the surface of the low refractive index layer 4 facing the inner panel 2).

[0129] Figure 13 The variants shown in the figure are basically corresponding to Figure 6 This is a variant of [the original text], so only the differences will be discussed here, and for other aspects please refer to [the original text]. Figure 6 Related descriptions or related Figure 4 Related descriptions. Figure 13The sandwich panel 100 further comprises a fifth adhesive interlayer 3.5, which is arranged adjacent to the inner panel 2 and between the second adhesive interlayer 3.2 and the inner panel 2. The second adhesive interlayer 3.2 is arranged between the fifth adhesive interlayer 3.5 and the first adhesive interlayer 3.1. A low refractive index layer 4 is arranged on the inner surface ii of the adhesive interlayer 3.1. Light scattering elements 5 are applied, for example as an imprint, to the surface of the second adhesive interlayer 3.2 facing the inner panel 2 (i.e., the inner surface). Alternatively, they may also be applied to the surface of the fifth adhesive interlayer 3.5 facing the functional element 8 (the outer surface). The adhesive interlayer 3.1 is formed, for example, based on PVB and has a layer thickness of 0.38 mm, and is colored. The second adhesive interlayer 3.2 and the fifth adhesive interlayer 3.5 are, for example, transparent (i.e., uncolored) and formed based on PVB. The fifth adhesive interlayer 3.5 is, for example, an interlayer without plasticizers.

[0130] Figures 14 to 16 The variants shown in the figure are basically corresponding to Figure 5 This is a variant of [the original text], so only the differences will be discussed here, and for other aspects please refer to [the original text]. Figure 5 Related descriptions or related Figure 4 Related descriptions. In Figures 14 to 16 In this variant, the adhesive interlayer 3.1 does not extend across the entire surface of the sandwich panel 100. A fifth adhesive interlayer 3.5 is disposed in the frame-like peripheral region of the sandwich panel 100 and extends around the adhesive interlayer 3.1 in a frame-like manner. Figure 16 In this variant, the fifth viscous interlayer 3.5 also extends around the second viscous interlayer 3.2. In this variant ( Figure 16 In the top view of the sandwich panel 100, the second adhesive interlayer 3.2 is arranged aligned with the adhesive interlayer 3.1. In this case, the fifth adhesive interlayer 3.5 has a layer thickness substantially corresponding to the total layer thickness of the adhesive interlayer 3.1, the second adhesive interlayer 3.2, and the low-refractive-index layer 4. For Figure 14 and Figure 15 The variant, the fifth viscous interlayer 3.5, has a layer thickness that substantially corresponds to the thickness of the viscous interlayer 3.1. exist Figure 14 and Figure 16 In the middle, a low-refractive-index layer 4 is applied to the outer surface i of the viscous intermediate film 3.1. Figure 15 In this case, a low-refractive-index layer 4 is applied to the inner surface ii of the adhesive interlayer 3.1. In all three variations, the low-refractive-index layer 4 therefore does not extend across the entire surface of the sandwich panel 100. Furthermore, Figures 14 to 16The variant has only one optical coupling device 7 in the edge region of the sandwich panel 100, wherein optionally more than one optical coupling device 7 (not shown here) may be arranged in the sandwich panel 100. For this variant, the low-refractive-index layer 4 can be easily coated onto the adhesive interlayer 3.1 without having to shield certain areas during the coating process (e.g., magnetron sputtering). Since the edge region does not have the low-refractive-index layer 4, it is better protected from external influences.

[0131] Figure 17 and Figure 20 The variants shown in the figure are basically corresponding to Figure 5 Variations of [the original text], therefore only the differences will be discussed here, and for other aspects please refer to [the original text]. Figure 5 Related descriptions or related Figure 4 Related descriptions. In Figure 17 and Figure 20 In this configuration, the low-refractive-index layer 4 extends only on a portion of the surface of the sandwich panel 100. The peripheral edge regions of the sandwich panel 100 do not have the low-refractive-index layer 4. Furthermore, Figure 17 and Figure 20 The variant has only one optical coupling device 7 in the edge region of the mezzanine panel 100, wherein optionally, more than one optical coupling device 7 (not shown here) may be arranged in the mezzanine panel 100. Figure 20 In this process, the photocoupler 7 is applied to the outer surface i of the adhesive interlayer 3.1. The adhesive interlayer 3.1 is preferably a plasticizer-free PVB-based film with a layer thickness of, for example, 0.05 mm, but alternatively it may be a plasticizer-based PVB film with a layer thickness of, for example, 0.38 mm.

[0132] Figure 18 and 19 The variants shown in the figure are basically corresponding to Figure 6 Variations of [the original text], therefore only the differences will be discussed here, and for other aspects please refer to [the original text]. Figure 6 Related descriptions or related Figure 4 Related descriptions. In Figure 18 and Figure 19 In this configuration, the low-refractive-index layer 4 extends only on a portion of the surface of the sandwich panel 100. The peripheral edge regions of the sandwich panel 100 do not have the low-refractive-index layer 4. Furthermore, Figure 18 and Figure 19 The variant has only one optical coupling device 7 in the edge region of the mezzanine panel 100, wherein optionally, more than one optical coupling device 7 (not shown here) may be arranged in the mezzanine panel 100. Figure 18 In this process, the optical coupling device 7 is applied to the surface (outer surface) of the second adhesive intermediate film 3.2 facing the functional element 8. Figure 19In this process, the optical coupling device 7 is applied to the inner surface ii of the adhesive interlayer 3.1. The second adhesive interlayer 3.2 is particularly preferably a plasticizer-free film based on PVB, with a layer thickness of, for example, 0.05 mm, but alternatively it may be a plasticizer-containing film based on PVB, with a layer thickness of, for example, 0.38 mm.

[0133] Figures 21 to 27 Different variations of the glass window element 101 according to the present invention are shown. Figures 21 to 27 Various embodiments of the glass window element 101, in addition to embodiments of the sandwich panel 100 according to the invention, also include a light source 9 that couples light 10 into the sandwich panel 100, or is arranged to couple light 10 into the sandwich panel 100. In all variations, the light source 9 includes, for example, a light-emitting diode (LED) that emits light 10 having, for example, a wavelength of 550 nm.

[0134] Figure 21 and Figure 22 The variant of the mezzanine panel 100 shown in the figure is basically corresponding to Figure 4 This is a variant of [the original text], so only the differences will be discussed here, and for other aspects please refer to [the original text]. Figure 4 Related descriptions. (and) Figure 4 Unlike the interlayer panel 100 in this embodiment, the interlayer panel 100 here does not have the optical coupling device 7. In these variant glass window elements 101, the light source 9 is arranged in a recess in the inner panel 2. The recess is, for example, a hole in the inner panel 2. When viewed from inside the vehicle through the interlayer panel 100, the recess is arranged in front of the black overlay 6. The light source 9 is arranged such that the light 10 emitted by the light source 9 strikes the edge surface of the inner panel 2 located in the recess and is subsequently coupled into the inner panel 2 using total internal reflection. Figure 21 In this variant, the low-refractive-index layer 4 does not extend across the entire surface of the sandwich panel 100. Specifically, the low-refractive-index layer 4 is absent from the peripheral edge regions of the sandwich panel 100. Figure 20 In the variant, the low refractive index layer 4 is disposed on the outer surface i of the viscous intermediate film 3.1, rather than on the inner surface ii of the viscous intermediate film 3.1.

[0135] Figure 23 The variant of the mezzanine panel 100 shown in the figure is basically corresponding to Figure 22 This is a variant of [the original text], so only the differences will be discussed here, and for other aspects please refer to [the original text]. Figure 22 Related descriptions or related Figure 4 Related description. In this embodiment, the insert 2 has no recess. Instead, the light source 9 is arranged in the peripheral edge region of the insert 2. The light source 9 is arranged such that the light emitted by the light source 9 strikes the edge surface region of the insert 2 and is subsequently coupled into the insert 2 using the total internal reflection effect.

[0136] Figure 24 The variant of the mezzanine panel 100 shown in the figure is basically corresponding to Figure 21 This is a variant of [the original text], so only the differences will be discussed here, and for other aspects please refer to [the original text]. Figure 21 Related descriptions or related Figure 4 Related description. In this embodiment, the insert 2 has no recess. Instead, the light source 9 is arranged in the peripheral edge region of the insert 2. The light source 9 is arranged such that the light 10 emitted by the light source 9 strikes the edge surface region of the insert 2 and is coupled into the insert 2 by utilizing the total internal reflection effect.

[0137] Figure 25 and Figure 26 The variant of the mezzanine panel 100 shown in the figure is basically corresponding to Figure 21 This is a variant of [the original text], so only the differences will be discussed here, and for other aspects please refer to [the original text]. Figure 21 Related descriptions or related Figure 4 Related description. In these embodiments, the inset panel 2 has no recess. Instead, a light source 9 is arranged in the edge region of the inset panel 2 on its inner surface IV. The light source 9 illuminates an optical coupling device 7, which is also arranged on the inner surface IV of the inset panel 2. The optical coupling device 7 is, for example, designed as a housing coated with a microprism film. The beam path of the light source 9 is, for example, parallel to the extending direction of the inset panel 2. The light 10 from the light source 9 strikes the optical coupling device 7 and is reflected by the microprism film, causing it to couple into the inset panel 2. Figure 26 In the process, the low refractive index layer 4 is applied to the outer surface i of the viscous interlayer film 3.1 and extends over the entire surface of the sandwich panel 100, but may optionally extend only over a portion of the surface of the sandwich panel 100.

[0138] The optical coupler 7 may also be optionally directly attached to the light source 9. Alternatively, the optical coupler 7 may be arranged between the insert 2 and the light source 9, wherein the illumination direction of the light source 9 is preferably substantially perpendicularly aligned with the inner surface IV (not shown) of the insert 2. In this case, the light 10 is deflected by the optical coupler 7 (e.g., through light refraction), causing it to couple into the insert 2.

[0139] Figure 27A further embodiment of the glass window element 101 according to the invention is shown. The sandwich panel 100 is designed, for example, as a vehicle canopy panel. The sandwich panel 100 includes an outer panel 1 and an inner panel 2, wherein an intermediate panel 11 is disposed between the outer panel 1 and the inner panel 2. An adhesive interlayer 3.1 and a second adhesive interlayer 3.2 are disposed between the inner panel 2 and the intermediate panel 11. The adhesive interlayer 3.1 is disposed adjacent to the inner panel 2 and has a low refractive index layer 4 on its outer surface i (i.e., the surface facing away from the inner panel 2). Alternatively, the low refractive index layer 4 may also be applied to the inner surface ii of the adhesive interlayer 3.1. A black overlay 6 is disposed on the peripheral edge region of the outer panel 1 and on the inner surface II of the outer panel 1 and prevents transparency. For example, all adhesive interlayers 3.1, 3.2, and 3.3 are formed based on plasticizer-free PVB. Alternatively, the intermediate films 3.1, 3.2, and 3.3 may also be formed based on EVA, TPU, or polyacrylate compounds, preferably without plasticizers.

[0140] Multiple light scattering elements 5 are arranged or formed on the outer surface III of the inner panel 2, for example, as imprints or roughening. A third adhesive interlayer 3.3 is arranged between the outer panel 1 and the intermediate panel 11, adhesively bonding the outer panel 1 and the intermediate panel 11 to each other. The inner panel 2, the adhesive interlayer 3.1, and the second adhesive interlayer 3.2 extend only on a portion of the surface of the outer panel 1, for example, only on the transparent area of ​​the interlayer panel 100. A light source 9 is arranged in a portion of the peripheral edge surface of the inner panel 2, and is arranged such that the light 10 emitted by it is coupled into the inner panel 2.

[0141] Optionally, Figure 2 , 3 The light source 9 of all glass window elements 101 from 21 to 27 can also be equipped with a collimator.

[0142] Reference number 1. Outer panel 2. Interior panel 3 intermediate layers 3.1 Adhesive Interlayer 3.2 Second viscous intermediate film 3.3 Third viscous intermediate film 3.4 Fourth viscous intermediate film 3.5 Fifth viscous intermediate film 4 Low Refractive Index Layer 5 light scattering elements 6 Black Overlay Printing Material 7 Optical Couplers 8 functional components 9 light sources 10 light sources 9 light 11. Middle panel 100 Mezzanine Panels 101 Illuminated Glass Window Components Outer surface of I outer panel 1 II. Inner surface of outer panel 1 III. Outer surface of the inner panel 2 Inner surface of IV inner panel 2 outer surface of i-viscous interlayer 3.1 ii. The outer surface of the viscous intermediate film 3.1.

Claims

1. A sandwich panel (100) for a luminous glass window element (101), comprising: -Outer panel (1), -Inner panel (2), having an outer surface (III) facing the outer panel (1) and an inner surface (IV) facing away from the outer panel (1), - An adhesive interlayer (3.1) disposed between the inner panel (2) and the outer panel (1), and having an outer surface (i) facing the outer panel (1) and an inner surface (ii) facing the inner panel (2), and - A low refractive index layer (4) is applied to one of the surfaces (i, ii) of the viscous intermediate film (3.1). The refractive index of the low-refractive-index layer (4) is at least 0.1 lower than that of the inner plate (2). The viscous intermediate film (3.1) has a layer thickness of 5µm to 100µm.

2. The sandwich panel (100) according to claim 1, wherein, At least one light scattering element (5) is disposed between the inner plate (2) and the low refractive index layer (4).

3. The sandwich panel (100) according to claim 1 or 2, wherein, At least one light scattering element (5) is applied to the inner surface (IV) and / or the outer surface (III) of the inlay plate (2), preferably only the outer surface (III).

4. The sandwich panel (100) according to any one of claims 1 to 3, wherein, At least one further adhesive intermediate film (3.2) is disposed between the adhesive intermediate film (3.1) and the inner panel (2).

5. The sandwich panel (100) according to any one of claims 1 to 4, wherein the adhesive interlayer (3.1) has a plasticizer content of less than 5%, preferably less than 1%, and is particularly free of plasticizer.

6. The sandwich panel (100) according to any one of claims 1 to 5, wherein, The viscous intermediate film (3.1) has a layer thickness of 10µm to 75µm, preferably 25µm to 50µm.

7. The sandwich panel (100) according to any one of claims 1 to 6, wherein, The viscous interlayer (3.1) is formed based on polyvinyl butyral, ethylene-vinyl acetate copolymer, polyacrylate compound or thermoplastic polyurethane.

8. The sandwich panel (100) according to any one of claims 1 to 7, wherein, The low refractive index layer (4) is applied to the inner surface (ii) of the viscous intermediate film (3.1).

9. The sandwich panel (100) according to claim 8, wherein, Two further adhesive intermediate films (3.2, 3.3) are arranged between the adhesive intermediate film (3.1) and the inner plate (2).

10. The sandwich panel (100) according to any one of claims 1 to 7, wherein, The low refractive index layer (4) is disposed on the outer surface (i) of the viscous intermediate film (3.1).

11. The sandwich panel (100) according to any one of claims 1 to 10, wherein, The low refractive index layer (4) has a refractive index of up to 1.50, preferably up to 1.45, and particularly preferably up to 1.

40.

12. The sandwich panel (100) according to any one of claims 1 to 11, wherein, The low refractive index layer (4) comprises a polymer matrix of polyacrylate, and silica-based particles are embedded in the polymer matrix.

13. The sandwich panel (100) according to any one of claims 1 to 12, wherein, The low-refractive-index layer (4) extends over the entire surface of the sandwich panel (100), except for the frame-like peripheral edge region.

14. A luminescent glass window element (101), comprising: - The sandwich panel (100) according to any one of claims 1 to 13, and -Light source (9), The light source (9) is arranged such that its light (10) can be at least partially coupled into the inner panel (2).

15. The glass window element (101) according to claim 14, wherein, The inner panel (2) has an optical coupling device (7) which is in the form of a reflective structure on or in the outer surface (III), and the light source (9) is arranged such that the light (10) can be reflected at the optical coupling device (7) and thus coupled into the inner panel (2).

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