Light-emitting plate

Abstract

The invention relates to a lighting panel (101) capable of emitting light in a directed manner, in particular a panel for a vehicle. The lighting panel (101) comprises a light guide plate (020) having a first main surface (01), a second main surface (02) and an edge (03), a light source (81) adhered to any one of said first main surface (01), second main surface (02) or edge (03) of the light guide plate (010), characterized in that the light guide plate (020) comprises a light blocking layer (71) on at least a portion of one of its main surfaces. The invention further relates to a composite panel comprising said lighting panel (101), to a method for providing said lighting and / or composite panel and to the use thereof.

Description

[0001] This invention relates to an illumination panel capable of emitting light in a directional manner, particularly for use in vehicles. The invention further relates to a composite panel including the illumination panel, a method for providing the illumination and / or the composite panel, and their uses.

[0002] Known practice involves incorporating light-emitting diode (LED) modules at the edge of a monolith or laminate in such a way that light emitted by the LED enters the material sheet, such as glass or polymer, and is thereby guided to a scattering element (also known as a light extraction device).

[0003] Lighting panels typically function as ambient lighting. The light extraction device scatters the light extracted from the light-emitting sheet in all directions without distinction. The scattering angle of the extracted light may be limited, for example, in the residential field when it is desirable to illuminate a specific decorative element to enhance it, or in the automotive field when it is desirable to illuminate areas of the passenger compartment close to the passengers without inconveniencing other passengers, especially the driver.

[0004] Composite plates including at least one light guide plate (and thus having an illumination function) are known in the art, wherein light-emitting diode (LED) modules are known to be incorporated at the edges of the composite plate such that light emitted by the LEDs enters through the edges of an inner plate that typically acts as a light guide layer.

[0005] WO 2020156737 relates to a vehicle window glass comprising an outer window glass component (16) and an inner window glass component (18), at least one light source (30), and a light scattering layer for light emitted by the light source (30). The light scattering layer is located between the inner window glass component (18) and the outer window glass component (16) and is formed of a polymer-dispersed liquid crystal (PDLC) layer (22).

[0006] WO 2021198262 relates to a vehicle window glass comprising a window glass body assembly having an outer surface facing the vehicle environment and an inner surface facing the vehicle interior, and having a light guide layer and a light source (24) from which light can be coupled into the light guide layer. A coupling element (28) is located on the inner surface of the window glass body assembly and couples light emitted by the light source (24) into the light guide layer.

[0007] However, there is still a need for improved illuminateable mounting glass with reduced light loss through the light guide plate (or light guide layer), so that the propagating light diffuses uniformly through the longest possible path.

[0008] Therefore, the objective is to provide an illumination panel and / or composite panel having improved light guiding, such that light intensity is maintained through the illumination panel, and the quality and uniformity of light color are maintained through propagation within the illumination panel.

[0009] This objective is achieved according to the lighting panel of the present invention, which comprises: - A light guide plate having a first main surface, a second main surface, and edges. - A light source that is adhered to any one of the first main surface, the second main surface, or the edge of the light guide plate. The light guide plate is characterized by including a light-blocking layer on at least a portion of one of its main surfaces.

[0010] Lighting panels are designed to separate interior spaces, such as the interior of a vehicle or building, from the external environment through windows.

[0011] In another embodiment of the invention, the lighting panel may be configured as a single sheet, but may be configured as a composite panel comprising at least two individual sheets adhered to each other in a known manner by a thermoplastic interlayer, wherein at least one of the sheets is the lighting panel of the invention.

[0012] Within the scope of this invention, the term "light guide plate" will always refer to a light-emitting plate illuminated by one or more light sources. In the installation location, the light guide plate or light-emitting sheet is preferably in contact with the interior of a vehicle or building.

[0013] The light guide plate includes a first main surface, a second main surface, and an edge. Within the scope of this invention, the first main surface will be the surface of the plate facing the interior space in the mounting position, while the second main surface will be the surface oriented towards the external environment in the mounting position.

[0014] Within the scope of this invention, a portion of the main surface is ranging from 1% to 99% of the surface area of ​​the entire surface.

[0015] The light guide plate can be a glass sheet or a plastic sheet, which contains or is composed of the following: polymethyl methacrylate (PMMA), polycarbonate, polyethylene terephthalate (PET), polyolefin, polyvinyl chloride (PVC), or mixtures thereof.

[0016] In most cases, the light guide plate is a glass substrate.

[0017] The glass can be any type, such as conventional float glass or flat glass, and can be any composition with any optical properties, such as any value greater than 10% for visible light transmittance, ultraviolet transmittance, infrared transmittance, and / or total solar transmittance.

[0018] Therefore, the glass can be sodium-calcium-silicon, aluminosilicate, or borosilicate type glass, etc.

[0019] The glass can be a regular transparent, colored, or ultra-transparent (i.e., low iron content and high transmittance) glass substrate. Other examples of glass substrates include transparent, green, bronze, or blue-green glass substrates.

[0020] Preferred glass substrates for light guides or light conductors can be selected from transparent or ultra-transparent soda-lime glass to achieve optimal light scattering and propagation. These typically have a light transmittance of at least 89% (for a glass sheet thickness of 4 mm). They can be considered colorless when viewed through their main surface.

[0021] The glass can be annealed glass, tempered glass, or heat-strengthened glass.

[0022] The light guide plate can have a thickness ranging from 0.5 mm to 15 mm, alternatively from 0.5 mm to 10 mm, alternatively from 0.5 mm to 8 mm, or alternatively from 0.5 mm to 6 mm. The optimal thickness of the lighting plate can be in the range of 0.5 to 4 mm, making it easy to apply in architectural or automotive applications.

[0023] The light source adhered to any of the first main surface, the second main surface, or the edge can be one or more light-emitting diodes mounted on a lateral support fixed to the edge of the illumination panel—the peripheral light source has an emitting surface facing the injection edge (with or without contact with the edge), or fixed to the first or second main surface of the light guide plate—the peripheral light source has an emitting surface facing the injection side of the first main surface, to propagate injected visible light within the thickness of the inner plate that serves as the light guide for injected light. Preferably, the light source is adhered to the first main surface or the edge of the light guide plate.

[0024] Examples of light sources include light-emitting diodes (LEDs) and optical fibers coupled to diodes.

[0025] Specifically, these can be LED light strips, which can be attached to a light guide plate by means of coupling elements. The coupling elements can be made of glass, PMMA (polymethyl methacrylate), PC (polycarbonate), PA (polyamide), COC (cyclic olefin copolymer), or COP (cyclic olefin polymer).

[0026] The coupling element can be arranged on the edge of the light guide plate or on the first main surface or the second main surface. Preferably, the coupling element can be directly attached to the first main surface of the light guide plate to facilitate bonding and reduce the complexity of mounting the final illumination panel within the frame, and further to allow light emitted by the light source to be coupled into the light guide layer over a large area.

[0027] Therefore, the coupling element guides the light emitted by the light source into the light guide plate at a defined angle, resulting in higher coupling efficiency.

[0028] Glass typically has a refractive index of 1.52, while polyvinyl butyral typically has a refractive index of 1.48, and polyurethane films have a refractive index of 1.49. Air and vacuum have a refractive index of 1.00. The values ​​of refractive index are considered at a wavelength of 550 nm.

[0029] To maintain total internal reflection (TIR) ​​in the light guide plate, the angle of incidence of light should be equal to or less than the critical angle θ defined by the following formula. C This depends on which materials are considered for the light guide plate and its surrounding medium: θ C = 90° - sin -1 (n2 / n1) Where n2 < n1

[0030] When considering a glass plate with a refractive index n1 of 1.52 and air with a refractive index n2 of 1.0 as the surrounding medium, the critical angle θ C = 49°. The critical angle θ is calculated when considering a glass plate with a refractive index n1 of 1.52 and an adjacent polyvinyl butyral interlayer with an index n2 of 1.48. C = 13°.

[0031] Light rays outside this range are not coupled in and therefore do not propagate within the light guide plate, as total internal reflection (TIR) ​​would not be maintained. Consequently, the coupling elements positioned on the first primary surface of the light guide plate guide light emitted from the light source into the light guide layer at a defined angle, achieving higher coupling efficiency. This improves the brightness and brightness uniformity of the light guide plate surface.

[0032] This allows the light guide layer to be optimally adapted to the requirements in terms of the size (large area) of its mounting glass or its base area.

[0033] Light sources and coupling elements suitable for lighting panels, as well as devices for adhering to light guide plates, are known in the art.

[0034] The lighting panel of the present invention is characterized in that it includes at least one light-blocking layer disposed on at least a portion of one of the main surfaces of the light guide plate.

[0035] The light-blocking layer disclosed herein indicates a material having a refractive index of less than 1.52, preferably less than 1.48, and more preferably less than 1.45 at 550 nm.

[0036] A light-blocking layer with a refractive index < 1.52, positioned on at least one surface of the light guide plate, is used to isolate light propagation within the light guide plate and its interaction with other potential components of the illumination plate. The positioning of the blocking layer ensures that injected light propagates primarily only through the light guide / inner plate and does not inappropriately exit from its defined path. The lower the refractive index, the more efficiently the blocking layer can be used for light propagation through the light guide plate, with greater uniformity in intensity and color definition.

[0037] At least one light-blocking layer may include a thin film coating of at least one of SiO2, CaF, and MgF2, and / or a layer of at least one polymer such as an epoxy polymer, an acrylic polymer, an alternating copolymer of fluoroethylene / vinyl ether; a fluoroacrylic acid copolymer, polyvinyl acetate and polyvinyl alcohol, or a silicone-based polymer.

[0038] When at least one barrier layer is a thin film coating, it can be provided by physical vapor deposition (sputtering) process (PVD), or chemical vapor deposition (CVD), or plasma-enhanced chemical vapor deposition (PECVD).

[0039] These methods can provide barrier layers with thin film coatings having a geometric thickness of 100 to 1500 nm, preferably 150 to 1200 nm.

[0040] When at least one barrier layer is a polymer layer, it can be provided by methods such as sol-gel process, dip coating, roll coating, curtain coating, etc.

[0041] These methods can provide barrier layers with polymer layers having geometric thicknesses of 50 nm to 5000 nm, alternatively 200 nm to 3500 nm, or alternatively 400 nm to 3000 nm.

[0042] Preferably, the barrier layer is a thin film coating of at least one of SiO2, MgF2, and CaF, because these can be readily provided for large-area surfaces in a reproducible manner, while polymer layers may be more complex to process uniformly on large surfaces.

[0043] Most preferably, the barrier layer is a silica layer with a refractive index of 1.30 to 1.50, or preferably up to 1.45 and even more preferably up to 1.40. An example of such a suitable silica barrier layer can be a porous (nanostructured) SiO2 silica layer. The main advantages of this material are its stability to weathering and its convenient, uniform deposition. Furthermore, it is compatible with a wide variety of other components that can be set or adhered to the lighting panel.

[0044] Such a porous (nanostructured) SiO2 silica layer can be obtained by PECVD, in which a layer containing silicon, oxygen, carbon, and hydrogen is deposited on a substrate and then the carbon and hydrogen content is reduced, so that the porous silica layer remains on the substrate, as detailed in patent application EP 1679291 A1. This method allows for the reduction of hydrogen and carbon content by causing vacancies to occur and remain at the atomic scale, distributed substantially uniformly across the layer.

[0045] At least one light-blocking layer may be positioned on the first main surface and / or the second main surface of the light guide plate, such that the light is contained within the light guide plate and does not diffuse out. This coupling maintained within the light guide plate allows for more efficient light propagation and rendering at the intended location.

[0046] In either case, at least one light-blocking layer is preferably present on and in contact with the portion of the main surface (i.e., the portion on which it is deposited).

[0047] Since other components of the lighting panel can be present on any of the main surfaces, certain precautions and constraints need to be considered in conjunction with embodiments of the present invention. Examples of elements, such as decoupling devices, low emissivity coatings, infrared reflective coatings, etc., will be described below.

[0048] When the light-blocking layer is present on a portion of the first main surface, the light source should be carefully positioned on an area of ​​the first main surface without the light-blocking layer to ensure contact between the light source and the light guide plate.

[0049] The light guide plate of the present invention may further include a decoupling device.

[0050] The decoupling device, preferably located on at least a portion of the second main surface of the light guide plate opposite to the first main surface, allows laterally coupled light to exit preferably via the first main surface of the light guide plate facing the interior environment.

[0051] The decoupling device can be a textured or embossed area on the second primary surface of the light guide plate. Such a textured surface can be obtained through texturing methods, such as laser processing or etching (e.g., by sandblasting), while an embossed surface can be obtained by applying paint or varnish to the second primary surface of the inner plate. Both textured and embossed areas exhibit refractive and / or scattering effects, allowing light to preferentially exit from the first primary surface of the light guide plate (the extraction surface) facing the internal environment. Depending on the desired final effect of light decoupling, the decoupling device can be designed to completely cover the surface or only cover a defined area, such as with a pattern or decorative contour.

[0052] When (and if) the light-blocking layer is combined with a decoupling device on a portion of the second main surface, the decoupling device is preferably positioned on and in contact with the second main surface, while the light-blocking layer (if present) is positioned above the decoupling device. In some cases, when the decoupling device is designed as a patterned area, the light-blocking layer may be positioned above both the area with and without the decoupling device, in direct contact with the second main surface of the light guide plate.

[0053] The present invention also relates to a composite board comprising: 1) The lighting panel described above includes: a. A light guide plate having a first main surface, a second main surface, and edges. b. A light source adhered to any one of the first main surface, the second main surface, or the edge of the light guide plate, characterized in that the light guide plate includes a light-blocking layer on at least a portion of one of its main surfaces. 2) Thermoplastic materials, 3) A second plate having a first main surface and a second main surface. The thermoplastic material is used to bond the two plates together by adhering the second main surface of the light guide plate to the first main surface of the second plate.

[0054] The composite panel of the present invention is also intended to separate interior spaces, such as the interior of a vehicle or building, from the external environment within a window.

[0055] Therefore, the composite panel includes a lighting panel as the inner panel and a second panel as the outer panel, which are bonded to each other via a thermoplastic interlayer.

[0056] In the context of this invention, "inner plate" is a plate facing inward at the mounting position, and specifically, in this document, the inner plate will be the light guide plate of the lighting plate.

[0057] "Outer panel" refers to the second panel facing the external environment at its installation position. In the context of this invention, "first main surface" means the inward-facing surface of the panel at its installation position. In the context of this invention, "second main surface" means the inward-facing surface of the panel at its installation position.

[0058] The surfaces of the composite panel are typically referred to as follows: The second main surface of the outer panel is referred to as side 1. The first main surface of the outer panel is referred to as side 2. The second main surface of the inner panel is referred to as side 3. The first main surface of the inner panel is referred to as side 4. The first main surface of the outer panel and the second main surface of the inner panel face each other and are bonded together by a thermoplastic interlayer.

[0059] The second sheet can be a glass sheet or a plastic sheet, comprising or composed of the following: polymethyl methacrylate (PMMA), polycarbonate, polyethylene terephthalate (PET), polyolefin, polyvinyl chloride (PVC), or mixtures thereof.

[0060] In most cases, both the second plate and the light guide plate will be independently selected from the glass substrates of the glass types discussed above.

[0061] While the inner panel is preferably selected from clear or ultra-clear soda-lime glass to achieve optimal light scattering and propagation, there is no particular preference for the outer panel. That is, the outer panel can be any suitable glass sheet used for window glazing, whether clear or colored.

[0062] The second plate may have a thickness ranging from 0.5 mm to 15 mm, alternatively from 0.5 mm to 10 mm, alternatively from 0.5 mm to 8 mm, or alternatively from 0.5 mm to 6 mm.

[0063] Both the second plate and the light guide plate can have a thickness ranging from 0.5 to 4 mm.

[0064] The two plates can have the same thickness, such as 0.5 mm, 0.8 mm, 1.2 mm, 1.6 mm, 2.1 mm, or 3 mm. This symmetrical structure in terms of glass thickness allows for ease of process and conventional shaping in the lamination process.

[0065] The two plates can also have different thicknesses, thus providing asymmetric laminated glass, for example, plate 1 = 0.5 mm and plate 2 = 2.1 mm, or plate 1 = 0.8 mm and plate 2 = 2.1 mm, or plate 1 = 0.5 mm and plate 2 = 1.6 mm, or plate 1 = 0.8 mm and plate 2 = 1.6 mm, or plate 1 = 1.6 mm and plate 2 = 2.1 mm. Such asymmetric structures in glass thickness allow for flexibility in curvature and / or weight management and / or in light / sunlight modulation.

[0066] The thermoplastic sandwich layer of the composite sheet of the present invention (also referred to as "polymer sandwich sheet", "thermoplastic sandwich", "sandwich") can be specified as a single-layer sheet or a multi-layer sandwich layer. A "single-layer sheet," as the name suggests, is a single or integral thermoplastic layer that is extruded as a single layer and then used to laminate two sheets. On the other hand, a multi-layer sandwich layer can include multiple layers of thermoplastic material, including individually extruded layers, co-extruded layers, or any combination of individually and co-extruded layers. Therefore, a multi-layer sandwich layer can include, for example: two or more single-layer sheets combined together ("multi-layer sheet"); two or more layers co-extruded together ("co-extruded sheet"); two or more co-extruded sheets combined together; a combination of at least one single-layer sheet and at least one co-extruded sheet; a combination of at least one multi-layer sheet and at least one co-extruded sheet; or any other desired combination of sheets.

[0067] Typical materials used for thermoplastic sandwiches include, but are not limited to, polyvinyl acetal, polyvinyl butyral, polyurethane, poly(ethylene-co-vinyl acetate), polyvinyl chloride, poly(vinyl chloride-co-methacrylate), polyethylene, polyolefins, ethylene acrylate copolymers, poly(ethylene-co-butyl acrylate), silicone elastomers, epoxy resins, and acid copolymers.

[0068] The thermoplastic film preferably contains polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), polyurethane (PU), and / or mixtures thereof and / or copolymers thereof, with polyvinyl butyral being particularly preferred.

[0069] These films are preferably based on the materials mentioned, but may contain other components such as plasticizers, photophores, heat-insulating particles, infrared-absorbing particles, polymer-dispersed liquid crystals, suspended particles, pigments, colorants, or UV absorbers, preferably in amounts of less than 50%.

[0070] The individual thermoplastic film layer preferably has a thickness of about 0.2 mm to 1 mm, for example 0.38 mm or 0.76 mm.

[0071] The thermoplastic interlayer is indicated for bonding the second primary surface of the light guide plate to the first primary surface of the second plate, regardless of whether these primary surfaces are provided with optional additional elements such as coatings or light-blocking layers. It should typically be understood herein that the adhesion of the two plates is not hindered by the presence of the optional components on either of the surfaces to be bonded.

[0072] The composite plate of the present invention may further include a low emissivity coating on at least one region of the first main surface of the light guide plate.

[0073] When discussing coatings in this invention, it means a coating comprising one or more layers of metal, metal oxide, metal nitride, metal oxynitride, metal carbide, or mixtures thereof. Within the scope of this invention, such coatings are typically obtained by physical vapor deposition or chemical vapor deposition methods. Such coatings can have a thickness ranging from 5 to 1000 nm.

[0074] In the coatings discussed herein, it should typically be understood that these layers are numbered sequentially, starting from the substrate surface. That is, the first layer should be understood as the first layer applied to the substrate, and the second layer as the second layer applied to the substrate above the first layer. The sequential order of position is considered to be upward relative to the substrate, up to the topmost layer.

[0075] Within the scope of this invention, the terms "below," "under," and "below" indicate the relative position of a layer with respect to the next layer in a layer sequence starting from the substrate. Within the scope of this invention, the terms "above" and "upper" indicate the relative position of a layer with respect to the next layer in a layer sequence starting from the substrate.

[0076] Within the scope of this invention, the relative positions of the layers within a stack do not necessarily imply direct contact between the layers. That is, an interlayer may be provided between the first layer and the second layer. For example, the first layer being "deposited on the substrate" does not preclude the presence of one or more other coatings of the same or different composition located between the first layer and the substrate, provided that it does not impair the purpose of this invention.

[0077] In some cases, a layer can actually consist of several or more separate layers.

[0078] Unless otherwise stated, all layer thicknesses in this document are geometric layer thicknesses.

[0079] Such a low-emissivity coating reflects thermal radiation, specifically IR radiation with wavelengths longer than the IR component of solar radiation. At low external temperatures, the low-emissivity coating reflects heat back inwards and reduces internal cooling. In the high external temperatures of summer, the low-emissivity coating on the inner side of the inner panel reduces the emission of thermal radiation from the panel into the interior, while in winter it reduces the emission of heat into the external environment. The low-emissivity coating positioned facing the vehicle compartment allows for a light reflectance Rin < 12% as observed from the interior, in addition to good durability, depending on the type of low-emissivity coating chosen.

[0080] However, the presence of such a low-emissivity coating on at least one area of ​​the first main surface of the light guide plate can interfere with the propagation of light through the light guide plate, thereby causing color shift in some cases. Therefore, a trade-off is required when combining various functions of lighting and thermal comfort in the same mounting plate. In addition to improving propagation through the longest possible path, the light-blocking layer of the present invention, in the presence of the low-emissivity coating, further allows color rendering to be maintained through the path within the light guide plate.

[0081] When a low-emissivity coating is present in the composite plate, at least one light-blocking layer exists beneath and in contact with the low-emissivity coating in at least one region on the first main surface of the light guide plate. The term "region" as used herein is intended to refer to 1% to 99% of the surface of the first main surface of the light guide plate to which the low-emissivity coating is disposed. If both are present, the "region" associated with the low-emissivity coating may be the same as "a portion of the first surface" relative to the light-blocking layer.

[0082] That is, when a low-emissivity coating is present on at least one area of ​​the first main surface of the light guide plate, a light-blocking layer is present beneath the low-emissivity coating and contacts the first main surface of the light guide plate in the same area. Specifically, the area of ​​the first main surface of the inner plate / light guide plate is sequentially provided with a first light-blocking layer from the plate surface outwards, followed by the low-emissivity coating as discussed above. In these cases, the light-blocking layer ensures effective light propagation through the inner plate / light guide plate and mitigates interference from the low-emissivity coating.

[0083] In such cases, a second light-blocking layer may exist on a portion of the thermoplastic interlayer facing the second main surface of the inner panel, but this is not necessarily required. The second main surface may also be provided with decoupling devices, as discussed above.

[0084] The low emissivity coating comprises: at least one functional layer containing a transparent conductive oxide (TCO), the transparent conductive oxide being selected from indium tin oxide, antimony-doped or fluorine-doped tin oxide, gallium-doped and / or aluminum-doped zinc oxide, mixed indium zinc oxide, vanadium oxide, tungsten-doped and / or magnesium-doped vanadium oxide, niobium-doped titanium oxide and / or cadmium stannate; or at least one nitride-based functional layer having low emissivity characteristics, the functional layer being selected from titanium nitride, chromium nitride, niobium nitride, molybdenum nitride, hafnium nitride, or mixtures thereof.

[0085] Preferred transparent conductive oxides (TCOs) may be selected from indium tin oxide, antimony-doped or fluorine-doped tin oxide and / or aluminum-doped zinc oxide (ZnO:Al) and / or gallium-doped zinc oxide (ZnO:Ga), wherein indium tin oxide or fluorine-doped tin oxide is the most preferred.

[0086] Preferred nitride-based functional layers may be selected from titanium nitride or chromium nitride, or mixtures thereof.

[0087] The refractive index of the material for the TCO functional layer is preferably between 1.7 and 2.5.

[0088] The emissivity of the plate according to the invention may be affected by the thickness of the functional layer of the low-emissivity coating. The thickness of at least one functional layer can range from 75 nm to 210 nm, preferably from 90 nm to 175 nm, and most preferably from 105 nm to 170 nm. This range allows for an optimal trade-off between the low emissivity of the plate and its heat treatment resistance. Within the scope of the invention, the low-emissivity coating may be characterized by an emissivity < 0.2 (according to standard EN 12898).

[0089] A first suitable low emissivity coating comprises, in sequence, a coating consisting of a first low refractive index layer (e.g., silicon oxide) and a transparent conductive oxide layer.

[0090] In a second suitable low-emissivity coating, at least one TCO functional layer may be surrounded by dielectric layers, which may have alternating low and high refractive indices. Specifically, the first dielectric layer (i.e., the layer below the TCO functional layer) may include a first sublayer of a high-refractive-index material, and subsequently a second sublayer of a low-refractive-index material. The second dielectric layer (i.e., the layer above the TCO functional layer) may include a third sublayer of a high-refractive-index material, and subsequently a fourth sublayer of a low-refractive-index material.

[0091] Examples of high refractive index dielectric layers (i.e., having a refractive index > 1.7, or alternatively > 1.8) include zirconium-doped titanium dioxide, silicon-doped titanium dioxide, mixed oxides of zinc and tin, and mixed oxides of titanium and silicon.

[0092] Examples of low refractive index dielectric layers (i.e., having a refractive index ≤ 1.6, or alternatively ≤ 1.55) include silicon oxide, zirconium-doped silicon oxide, mixed oxides of silicon and aluminum, and magnesium fluoride.

[0093] The optimal low emissivity coating comprises, in sequence, the following layers: a first high refractive index layer, a first low refractive index layer, a transparent conductive oxide layer, an optional barrier layer, a second low refractive index layer, and an optional top coating having a low refractive index.

[0094] The first high refractive index layer may have a thickness ranging from 7 to 23 nm, or alternatively from 8 to 20 nm, or alternatively from 9 to 19 nm.

[0095] The first low-refractive-index layer may have a thickness ranging from 18 to 55 nm, or alternatively from 20 to 50 nm, or alternatively from 25 to 45 nm.

[0096] The transparent conductive oxide layer may have a thickness ranging from 75 to 210 nm, or alternatively from 90 to 175 nm, or alternatively from 105 to 170 nm.

[0097] The optional barrier layer may have a thickness ranging from 0 to 15 nm, or alternatively from 1 to 15 nm, or alternatively from 1 to 12 nm.

[0098] The second low-refractive-index layer may have a thickness ranging from 40 to 110 nm, or alternatively from 45 to 105 nm, or alternatively from 50 to 95 nm.

[0099] The optional top coating may have a thickness ranging from 2 to 40 nm, or alternatively from 5 to 35 nm, or alternatively from 6 to 30 nm.

[0100] An optional topcoat can be a silicon oxide layer containing 5 to 40 mol% zirconium. Such a top layer allows for adjustment of the neutral color rendering of the low-emissivity coating along with excellent durability, such as resistance to scratches. In practice, the low-emissivity coating positioned towards the passenger compartment may be subject to abrasion and scratches from cleaning or passenger occupancy. Such passenger occupancy can affect the integrity of the coating, such as from friction by objects (umbrellas, balls, clothing, etc.). This top layer also provides compatibility and adhesion to fastening elements that will subsequently be used to secure the composite panel within the frame.

[0101] Therefore, the optimal low emissivity coating may comprise a coating comprising, in sequence, the following layers: a first high refractive index layer having a thickness ranging from 7 to 23 nm, a first low refractive index layer having a thickness ranging from 18 to 55 nm, a transparent conductive oxide layer having a thickness ranging from 75 to 210 nm, an optional barrier layer having a thickness ranging from 0 to 15 nm, a second low refractive index layer having a thickness ranging from 40 to 110 nm, and an optional top coating having a low refractive index having a thickness ranging from 2 to 40 nm.

[0102] Typically, a sheet of transparent float glass (soda-lime glass) with such an optimal low emissivity coating can have a light transmittance of 85% to 94%.

[0103] The optimal low emissivity coating of the present invention is characterized by an emissivity of < 0.15 (according to standard EN 12898).

[0104] Another example of a suitable low-emissivity coating may be a low-emissivity coating comprising at least two transparent conductive oxide layers separated by at least one dielectric material layer, each having a thickness ranging from 20 to 80 nm. Thus, such a low-emissivity coating may comprise n' TCO layers and n'+1 dielectric layers, where n' ≥ 1, such that each TCO layer is surrounded by two dielectric layers. Examples of dielectric layers for such a suitable low-emissivity coating include silicon oxide, silicon nitride, zinc oxide, tin oxide, or alloys or mixtures thereof.

[0105] Another suitable low emissivity coating can be sequentially included, starting from the substrate surface: • The first dielectric layer has a thickness of 1.5 to 200 nm. • First crystallinity improvement layer, with a thickness of 3 to 30 nm, • A first metal nitride functional layer, having a thickness of 3 to 60 nm, and • A second dielectric layer, having a thickness of 1.5 to 200 nm, •Optionally, a second crystallinity improvement layer, a second metal nitride functional layer, and a third dielectric layer are then applied. The crystallinity improvement layer comprises ZrNx, wherein x is greater than 1.2 and at most 2.0, and the metal nitride functional layer is selected from the group consisting of titanium nitride, chromium nitride, niobium nitride, molybdenum nitride and hafnium nitride, and may have a thickness ranging from 3 to 60 nm, and the first dielectric layer, the second dielectric layer and / or the third dielectric layer may have a thickness ranging from 1.5 to 2000 nm and advantageously comprise aluminum-doped silicon nitride.

[0106] The low emissivity coating, which includes a metal nitride functional layer, may further include a top layer comprising silicon dioxide, titanium nitride, and / or carbon.

[0107] In some embodiments of the invention compatible with the foregoing, the composite plate of the invention may further include an IR reflective coating present between the second plate and the light guide plate.

[0108] The primary function of such an IR reflective coating is to reflect the infrared portion of solar radiation, thereby reducing heat transfer toward the vehicle's interior.

[0109] The IR reflective coating may be embedded in (i.e., within) the thermoplastic interlayer, or at least one IR reflective coating may be applied directly to the first main surface of the outer panel or the second main surface of the inner panel.

[0110] When the IR reflective coating is embedded in the thermoplastic interlayer, the IR reflective coating is applied to a carrier film disposed between the two thermoplastic films. The carrier film preferably contains polyethylene terephthalate (PET) and has a thickness of 0.012 to 0.2 mm.

[0111] When an IR reflective coating is applied to the surface of a plate facing the thermoplastic interlayer, it is typically provided by a physical vapor deposition method.

[0112] An IR reflective coating may include n infrared reflective (IR) layers and n + 1 dielectric layers, where n ≥ 1, such that each IR layer is surrounded by two dielectric layers.

[0113] The IR reflective coating preferably comprises n infrared reflective (IR) layers and n + 1 dielectric layers, where n ≥ 1, such that each IR layer is surrounded by two dielectric layers. Such an IR reflective coating offers an optimal trade-off between sun protection efficiency and cost.

[0114] The IR reflective layer can be made of silver, gold, palladium, platinum or their alloys.

[0115] The IR reflective layer or functional layer can have a thickness of 2 to 30 nm, alternatively 5 to 20 nm, or alternatively 7 to 18 nm. These thickness ranges enable the achievement of desired sunlight control functions and / or electrical conductivity (when needed).

[0116] The dielectric layer may typically include oxides, nitrides, oxynitrides, or carbon oxides of Zn, Sn, Ti, Zr, Si, In, Al, Bi, Ta, Hf, Mg, Nb, Y, Ga, Sb, Mg, Cu, Ni, Cr, Fe, V, B, or mixtures thereof.

[0117] In some embodiments of the present invention, the dielectric layer may include oxides, nitrides, oxynitrides, or carbon oxides of Zn, Sn, Ti, Zr, Si, In, Al, Nb, Sb, Ni, Cr, V, Mb, Mg, or mixtures thereof. Alternatively, the dielectric layer may include oxides, nitrides, oxynitrides, or mixtures thereof of Zn, Sn, Ti, Zr, Si, In, Al, Nb, Sb, Ni, Cr.

[0118] These materials may optionally be doped, with examples of dopants including aluminum, zirconium, or mixtures thereof. Dopants or mixtures of dopants may be present in amounts up to 15 wt%.

[0119] Typical examples of dielectric materials include, but are not limited to, silicon-based oxides, silicon-based nitrides, zinc oxides, aluminum-doped zinc oxides, zinc-based oxides, tin oxides, mixed zinc-tin oxides, silicon nitrides, silicon nitrides, titanium oxides, aluminum oxides, zirconium oxides, niobium oxides, aluminum nitrides, bismuth oxides, mixed silicon-zirconium nitrides, and mixtures of at least two of these, such as titanium-zirconium oxides, titanium-niobium oxides, zinc-titanium oxides, zinc-gallium oxides, zinc-indium-gallium oxides (IGZO), zinc-titanium-aluminum oxides (ZTAO), zinc-tin-titanium oxides, zinc-aluminum-vanadium oxides, zinc-aluminum-molybdenum oxides, zinc-aluminum-magnesium oxides, zinc-aluminum-chromium oxides, zinc-aluminum-copper oxides, and zinc-titanium-zirconium oxides.

[0120] The dielectric layer may consist of multiple separate layers containing or substantially composed of the above materials.

[0121] Each dielectric layer may have a thickness ranging from 0.1 to 200 nm, alternatively from 0.1 to 150 nm, alternatively from 1 to 120 nm, or alternatively from 1 to 80 nm. Different dielectric layers may have different thicknesses. That is, the first dielectric layer may have the same or different, larger or smaller thickness than the thickness of the second or third or any other dielectric layer.

[0122] Typically, panels of transparent float glass (soda-lime glass) with such an IR reflective coating can have a light transmittance of 25% to 80%, provided that sunlight control is ensured for thermal comfort within the interior environment.

[0123] IR reflective coatings can be conductive coatings, such as conductive heating window coatings or single-film or multi-film coatings that can act as antennas.

[0124] Such IR reflective coatings are well known to those skilled in the art and do not require further elaboration in this article.

[0125] In some cases, alone or in conjunction with the foregoing, the composite plate of the present invention may further include a functional film selected from electrochromic films, suspended particulate devices (SPDs), polymer-dispersed liquid crystal (PDLC) films or guest-host liquid crystal (GHLCs), thermochromic films or photovoltaic modules.

[0126] Electrodynamic functional films can be used to alter the light transmittance of mounted glass, adjust hue, privacy, diffuse reflection, or provide thermal protection. In particular, these electrodynamic functional films are films that can switch between a dark state and a translucent or even transparent state, thus changing the light transmittance.

[0127] The electro-functional membrane can be disposed between the outer panel and the thermoplastic interlayer, more specifically, embedded within the interlayer or on and in contact with the first main surface of the outer panel. When embedded within the interlayer, the functional membrane can be disposed on a carrier film (such as a polyethylene terephthalate (PET) substrate) having a refractive index of 1.57-1.58.

[0128] Electrochromic films function by altering the transmittance of colored ions in the film composition. Suspended particulate devices (SPDs) comprise a layer of particles in a suspension, which are ordered or disordered depending on the applied voltage. Polymer-dispersed liquid crystal (PDLC) films consist of polymers containing liquid crystals that are sensitive to the applied voltage.

[0129] Thermochromic films work by changing the light transmittance of the mounting glass when switching between different temperatures, without requiring any voltage.

[0130] When such a functional membrane is present, the thermoplastic interlayer can therefore include several individual sheets of thermoplastic material, such that the individual sheets between the second main surface of the inner panel and the functional membrane have a light transmittance equal to or greater than 50%, allowing light emitted from the functional membrane layer to reach the internal environment.

[0131] There are no specific requirements for the light transmittance or color of the individual sheets of thermoplastic material between the functional film and the first main surface of the outer panel. However, for aesthetic purposes, preferably, their light transmittance is less than 50%, more preferably less than 25%, so that light emitted from the functional film is not visible from the outside, although other means may be used for similar aesthetic purposes.

[0132] Such a functional film can be disposed on a plastic substrate, or on another glass sheet inserted into the composite plate away from the light guide plate and facing the external environment, so that the function of the composite plate of the present invention for the propagation of light inward is not impaired.

[0133] Such additional glass sheets can have a thickness of 0.3 to 1.8 mm, preferably 0.3 to 1.2 mm. The thinner the sheet, the lighter the final weight of the composite panel.

[0134] The arrangement of the lighting panel with the light-blocking layer of the present invention has the following advantages: any component (such as a coating, switchable foil, or solar cell) can be added to the lighting panel without affecting the light traveling within the light guide plate. Furthermore, the light propagating through the light guide plate is unaffected by any switching of the switchable foil.

[0135] The present invention also relates to a method for obtaining a composite board, the method comprising the following steps: 1) Provide an illumination panel, the illumination panel including a light guide plate having a first main surface, a second main surface, and a light-blocking layer on at least a portion of one of its main surfaces. 2) Provide a second plate having a second main surface and a first main surface, 3) Provide thermoplastic sandwich panels, 4) Assemble the first main surface of the second plate and the second main surface of the light guide plate through the thermoplastic interlayer to provide laminated glass.

[0136] At least one light-blocking layer on at least a portion of one of the first or second main surfaces of the light guide plate may be provided as a thin film coating by the methods discussed above regarding the blocking layer (i.e., physical vapor deposition (sputtering) process (PVD), or chemical vapor deposition (CVD), or plasma-enhanced chemical vapor deposition (PECVD)).

[0137] The method of the present invention may further include the step of providing a low emissivity coating on the first main surface of the light guide plate.

[0138] The method of the present invention may further include the step of providing an infrared reflective coating on any of the second main surfaces of the inner panel, or on the first main surface of the outer panel, or within the thermoplastic interlayer.

[0139] The steps for providing low emissivity coatings and / or IR reflective coatings include a deposition step using a method selected from CVD, PECVD, PVD, magnetron sputtering, etc.

[0140] Different layers of the corresponding coating can be deposited using different techniques.

[0141] Glass plates with appropriate coatings can then be subjected to heat treatment to strengthen the glass plates and optimize the performance of the coatings.

[0142] Depending on the type of heat treatment and the thickness of the mounting glass, the heat treatment involves heating the mounting glass in air to at least 560°C, for example, between 560°C and 700°C, particularly to a temperature of approximately 630°C to 670°C, for a period of approximately 3, 4, 6, 8, 10, 12, or even 15 minutes. This treatment may include a rapid cooling step following the heating step to introduce a stress difference between the glass surface and the core, such that, in the event of impact, the so-called tempered glass will safely shatter into smaller pieces. If the cooling step is not too vigorous, the glass will then simply undergo heat strengthening and, in any case, provide better mechanical resistance.

[0143] The step of assembling two plates with at least one interlayer can be a lamination step of flat plates, or a bending step of bent laminates, which includes first bending the plates and then laminating the bent plates.

[0144] The composite panel can then be subjected to enamel deposition or prepared to be included within a frame.

[0145] The present invention also relates to the use of the lighting panel according to the invention as a window glass panel of a vehicle.

[0146] The present invention also relates to the use of the composite panel according to the invention as a window glass panel for vehicles.

[0147] The lighting panels and / or composite panels of the present invention can be particularly used as vehicle roofs. The window glass panels are preferably roof panels of vehicles, especially passenger cars, because they can optimally provide uniform light transmission from the visible surfaces of the passenger compartment.

[0148] Vehicles include those that can be used for road, air, water and water transport, especially automobiles, buses, trams, trains, ships, airplanes, spacecraft, space stations and other motor vehicles.

[0149] Window glass panels include rear windows, side windows, skylights, panoramic skylights, side windows, quarter lites (QLF) or any other type of glass that may be used for automobiles or any other type of transport device, wherein light transmittance >70% is not a mandatory feature.

[0150] The lighting panels and / or composite panels of this invention can also be useful in architectural applications. Architectural applications include displays, windows, doors, partitions, shower panels, etc.

[0151] In some cases, composite panels can be used as heated vehicle mounting glass.

[0152] The present invention also relates to the use of a light-blocking layer as a limiting device for light propagating within a light guide plate, wherein the light guide plate having a first main surface, a second main surface, and an edge is part of an illumination plate, the illumination plate further comprising a light source adhered to the first main surface or edge of the light guide plate, and wherein the light-blocking layer is present on the light guide plate, and on at least a portion of one of its main surfaces, the main surface being further provided with a low emissivity coating above and in contact with the light-blocking layer.

[0153] In practice, it was found that combining various functions of lighting and thermal comfort in the same mounting plate caused a contradictory effect of light interaction with the low-emissivity coating. This drawback was unexpectedly mitigated by inserting a light-blocking layer between the light guide plate and the low-emissivity coating responsible for thermal comfort, wherein the light-blocking layer is used to limit the optimal propagation of light emitted by the light source within the light guide plate of the lighting panel.

[0154] The invention is explained in detail below with reference to the accompanying drawings and exemplary embodiments. The drawings are schematic and not to scale. These drawings are in no way limiting of the invention.

[0155] Figure 1A cross-section of a lighting panel according to a first embodiment of the invention is depicted. The lighting panel 101 has a size of approximately 1 m² and is designed to separate an internal environment from an external environment. The lighting panel includes a light guide plate 010 having a first main surface 01 facing inwards, a second main surface 02 facing outwards, and an edge 03. Peripheral light sources and coupling elements 81 are positioned on the first main surface 01 of the light guide plate 010. Preferably, a plurality of peripheral light sources and coupling elements are arranged along the lateral edges of the lighting panel.

[0156] According to the present invention, Figure 1 The lighting panel includes a light-blocking layer 71 positioned on surface 01, facing the interior environment.

[0157] The decoupling element 72 is present on the main surface 02 of the light guide plate 010, and is in contact with the main surface 02 in the form of patterning or surface etching.

[0158] Light 09 is generated by a peripheral light source and coupling element 81 at a 13° angle. The light is emitted at an angle (06) toward the light guide plate 010 and propagates along the length of the light guide plate toward the other side.

[0159] The light-blocking layer of this invention allows light to be reflected with optimal uniform color and intensity throughout the entire path length.

[0160] Based on Figure 1 In some other embodiments, a low emissivity coating (not shown) may be present above and in contact with the light-blocking layer, facing the internal environment.

[0161] Figure 2 A cross-section is depicted through an embodiment of a composite panel 201 according to the invention. The composite panel includes an outer panel 10 and a light guide plate 20 joined together by a thermoplastic interlayer 30. The composite panel is intended to be used as a roof panel of a passenger vehicle, wherein the outer panel 10 is intended to face the external environment and the light guide plate 20 is intended to face the vehicle interior. The outer panel 10 has a second main surface 11 and a first main surface 12. The light guide plate 20 has a second main surface 21 and a first main surface 22. The second main surfaces 11 and 21 face the external environment in an installed state; the first main surfaces 12 and 22 face the vehicle interior in an installed position. The first main surface 12 of the outer panel 10 and the second main surface 21 of the light guide plate 20 face each other and are joined together by the thermoplastic interlayer 30. The outer panel 10 and the light guide plate 20 contain transparent soda-lime glass. In some instances, the light guide plate may be an ultra-transparent glass sheet. They may each have a thickness of 2.1 mm, or one sheet may have a thickness of 1.6 mm and the other sheet may have a thickness of 2.1 mm.

[0162] Thermoplastic interlayer 30 can typically have a thickness of 0.76 mm.

[0163] Figure 2 The composite panel includes a light-blocking layer 71 on surface 22, facing the interior environment in the mounting position. According to an embodiment of the invention, a low-emissivity coating 51 is further disposed above and in contact with the light-blocking layer 71.

[0164] The decoupling element 72 is present on the main surface 21 of the light guide plate 20, in the form of patterning or surface etching, and is in contact with the main surface 21, under and in contact with the thermoplastic interlayer 30.

[0165] Figure 2 It includes a peripheral light source and a coupling element 81 positioned on the inner surface (P4) of the light guide plate 20. Preferably, the peripheral light source and the coupling element 81 are in direct contact with the light guide plate.

[0166] Light 09 is generated by a peripheral light source and coupling element 81 at a 13° angle. The light is emitted at an angle (06) toward the light guide plate 010 and propagates along the length of the light guide plate toward the other side.

[0167] The light-blocking layer of this invention allows light to be reflected with optimal uniform color and intensity throughout the entire path length.

[0168] Enameled coatings or black imprints 61 and 62 can be provided as masking strips typically present on vehicle-mounted glass (intended for mounting on a chassis). Typical fastening methods can be used to secure the composite panel to the vehicle.

[0169] Figure 2 Various alternatives to the composite panel may further include an additional glass panel facing outwards, or a switchable membrane within the thermoplastic interlayer.

[0170] It is also possible to think that, in Figure 2 Within the variant of the composite panel, the IR reflective coating may be present on either surface 12 or 21, or within the interlayer 30.

[0171] In the above embodiments of the lighting panel, in a single panel or composite panel, the selected light-blocking layer allows for optimal light propagation through the light guide, such that its intensity and color definition remain stable over the entire length of the light path through the light guide.

[0172] A light-blocking layer is particularly useful when a low-emissivity coating is present on a light guide plate facing inwards. The low-emissivity coating can indeed negatively impact the overall light intensity of the plate, potentially causing color shifts. The presence of a light-blocking layer between the light guide plate and the low-emissivity coating ensures light isolation and optimal propagation within the plate. Example

[0173] Various composite plates were prepared, including a light guide plate (with a light-blocking layer) as an inner plate and a second / outer plate containing the following elements.

[0174] The second plate and the light guide plate are made of 2.1 mm transparent float glass, although the thickness is not critical for analyzing the behavior of light within the light guide with the light-blocking layer.

[0175] Low emissivity coatings (low e) are outlined in Table 1, where TiZrOx = a mixed oxide of titanium and zirconium, InSnOx = indium-doped tin oxide and SiZrOx = zirconium-doped silicon oxide. Table 1 result

[0176] To quantify the benefits of different embodiments, a key metric will be the level of internal light reflection within the light guide at two incident angles (i.e., 6° and 13° with respect to the glass surface).

[0177] For incident light wavelengths of 625 nm, 528 nm, and 465 nm, representing red, green, and blue (RGB wavelengths) respectively, the internal light reflectivities are shown and referred to as R_625, R_528, and R_465.

[0178] For different coating stacks and incident angles, the light reflectivity within the glass at the interface with the coating stack was calculated through simulation. The refractive index of the glass used in these simulations was 1.52, representing a typical glass composition used in industry.

[0179] Comparative Example 1 is a transparent float glass sheet. Standard light propagation within this transparent float glass sheet indicates that the three primary colors are reflected at 100%.

[0180] Comparative Example 2 is a transparent float glass sheet as in Comparative Example 1, with a first low emissivity coating as shown in Table 1 further disposed on the surface of the light guide plate facing the internal environment. In the absence of the light-blocking layer, some light loss was observed at different levels for RGB wavelengths at two viewing angles of 6° and 13°.

[0181] Comparative Example 3 is a transparent float glass sheet as in Comparative Example 2, with a low emissivity coating as shown in Table 1 applied to the surface of a light guide plate facing the internal environment. An unsuitable light-blocking layer, consisting of a 732 nm thick silica layer with a refractive index of 1.54 (>1.52), is further applied between the glass sheet and the low emissivity coating. No improvement in light loss was observed.

[0182] Comparative Example 4 is a transparent float glass sheet as in Comparative Example 1, with a second (and alternative) low-emissivity coating further disposed on the surface of a light guide plate facing the internal environment. In the absence of a light-blocking layer, due to the strong and harmful interaction of light with the layer of the low-emissivity coating, significant light loss was observed at different levels for red and blue wavelengths at two viewing angles of 6° and 13°, and some loss was observed for green wavelengths.

[0183] Example 1 is a transparent float glass sheet as in Comparative Example 1, with a first low-emissivity coating as shown in Table 1 further disposed on the surface of a light guide plate facing the internal environment, and a light-blocking layer of 512 nm thick silica layer with a refractive index of 1.50 further disposed. The blocking layer is located between the glass sheet and the low-emissivity coating, in contact with both. Compared to Comparative Example 1, light loss is reduced by at least 1% of the light reflectance value in all three color wavelengths at two angles of 6° and 13°. The appropriate light-blocking layer mitigates the interaction between light and the low-emissivity coating, thus actively maintaining propagation.

[0184] Example 2 is a repeat of Example 1, with a light-blocking layer consisting of a 512 nm thick silicon dioxide layer with a refractive index of 1.47. Light loss is reduced at both angles of 6° and 13°, achieving up to 100% reflectivity in blue and green wavelengths at the 6° angle.

[0185] Example 3 is a repeat of Example 1, with a light-blocking layer consisting of a 320 nm thick silicon dioxide layer with a refractive index of 1.40. Light loss is reduced at both angles of 6° and 13°, achieving up to 100% reflectivity in blue and green wavelengths at the 6° angle.

[0186] Examples 4 to 6 are based on a transparent float glass sheet as in Comparative Example 1, with a first low-emissivity coating as shown in Table 1 further disposed on the surface of a light guide plate facing the internal environment, and a light-blocking layer of silicon dioxide with a refractive index of 1.37 further disposed. The light-blocking layer is located between the glass sheet and the low-emissivity coating, and is in contact with both.

[0187] The barrier layer is porous (nanostructured) silica, obtained by plasma-enhanced CVD, as in EP 1679291 A1, in a mixed reactive gas atmosphere of argon, oxygen, and TMDSO, the latter having a total gas flow of The concentration was 5 atomic percent. In the CVD method, the plasma was excited by pulsed microwave radiation, with the pulse duration varying from 0.1 to 10 ms and the ratio of pulse pause to pulse duration set to 1:1 to 1:500. The content of silicon, oxygen, carbon, and hydrogen in the barrier layer was adjusted by regulating the gas mixture content and pulse parameters to achieve a refractive index n of 1.37 after annealing in a free atmosphere. The annealing conditions were typical for firing cycles applied to bent automotive glass, with the highest glass temperature in the cycle typically reaching 630°C to 650°C for 3 to 10 minutes.

[0188] The barrier layer has a thickness of 105 nm in Example 4; 284 nm in Example 5 and 400 nm in Example 6.

[0189] In Example 4, light loss was reduced at both angles of 6° and 13°, with a specific increase of at least 1% in light reflectance value across all three color wavelengths at the 13° angle.

[0190] In Example 5, light loss was reduced at both angles of 6° and 13°, with reflectivity reaching up to 100% in both blue and green wavelengths at the 6° angle.

[0191] In Example 6, light loss was significantly reduced at both angles of 6° and 13°, with almost no light loss.

[0192] As can be seen from Table 2, the presence of a light-blocking layer in contact with the first main surface of the light guide plate having a low-emissivity coating significantly improved the propagation of different colors / wavelengths of light according to Examples 1 to 6 compared to Comparative Example 2. Therefore, the presence of a light-blocking layer is particularly useful in recently developed mounting plates that include a low-emissivity coating for improving light propagation and reducing light loss. Table 2 .

Claims

1. A lighting panel comprising: a. A light guide plate having a first main surface, a second main surface, and edges. b. A light source adhered to any one of the first main surface, the second main surface, or the edge of the light guide plate. The light guide plate is characterized in that it includes a light-blocking layer on at least a portion of one of its main surfaces.

2. The lighting panel as claimed in claim 1, wherein, The at least one light-blocking layer is characterized in that its refractive index at 550 nm is less than 1.52, preferably less than 1.48, and more preferably less than 1.

45.

3. The lighting panel as claimed in any of the preceding claims, wherein, The at least one light-blocking layer comprises a thin film coating of at least one of SiO2, CaF, and MgF2, and / or a layer of at least one polymer such as an epoxy polymer, an acrylic polymer, an alternating copolymer of fluoroethylene / vinyl ether; a fluoroacrylic acid copolymer, polyvinyl acetate and polyvinyl alcohol, or a silicone-based polymer.

4. The lighting panel as claimed in any of the preceding claims, wherein, The at least one light-blocking layer comprises a thin film coating of at least one of SiO2, MgF2, and CaF.

5. The lighting panel as claimed in claim 5, wherein, The at least one light-blocking layer is present on and in contact with the portion of the main surface.

6. The lighting panel as claimed in any of the preceding claims, further comprising a decoupling device.

7. A composite panel comprising: 1) The lighting panel as described in any of the preceding claims, comprising: a. A light guide plate having a first main surface, a second main surface, and edges. b. A light source adhered to any one of the first main surface, the second main surface, or an edge of the light guide plate, characterized in that the light guide plate includes a light-blocking layer on at least a portion of one of its main surfaces. 2) Thermoplastic materials, 3) A second plate having a first main surface and a second main surface. The thermoplastic material is used to bond the two plates together by adhering the second main surface of the light guide plate to the first main surface of the second plate.

8. The composite plate of claim 7, further comprising a low emissivity coating on at least one region of the first main surface of the light guide plate.

9. The composite board as described in claim 8, wherein, At least one light-blocking layer exists under and in contact with the low-emissivity coating.

10. The composite plate according to any one of claims 7 to 9, further comprising an infrared reflective coating present between the second plate and the light guide plate.

11. The composite panel according to any one of claims 7 to 9, further comprising a functional membrane.

12. A method for obtaining a composite panel as described in any one of claims 7 to 11, comprising the following steps: 1) Provide an illumination panel, the illumination panel including a light guide plate having a first main surface, a second main surface, and a light-blocking layer on at least a portion of one of its main surfaces. 2) Provide a second plate having a second main surface and a first main surface, 3) Provide thermoplastic sandwich, 4) Assemble the first main surface of the second plate and the second main surface of the light guide plate through the thermoplastic interlayer to provide laminated glass.

13. The method of claim 12, wherein, The at least one light-blocking layer is provided as a thin film coating by physical vapor deposition (sputtering) process (PVD), chemical vapor deposition (CVD), or plasma-enhanced chemical vapor deposition (PECVD).

14. The method of any one of claims 11 or 12, further comprising the steps of providing a low emissivity coating on the inner surface of the inner panel and / or on any of the outer surfaces of the inner panel, or on the inner surface of the outer panel or within the thermoplastic interlayer.

15. Use of the lighting panel as a window glass panel of a vehicle as claimed in any one of claims 1 to 6.

16. Use of the composite panel as a window glass panel of a vehicle, as described in any one of claims 7 to 11.

17. The light-blocking layer serves as a device for limiting the propagation of light within a light guide plate. a. The light guide plate having a first main surface, a second main surface, and an edge is part of an illumination plate, and the illumination plate further includes a light source adhered to any one of the first main surface, the second main surface, or the edge of the light guide plate, and b. wherein the light-blocking layer is present on the light guide plate, on at least a portion of one of its main surfaces, the main surface being further provided with a low emissivity coating above and in contact with the light-blocking layer.

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