Luminous laminated glass panel comprising a functional coating

Abstract

The invention relates to a material intended for luminous laminated glass panels, comprising a substrate coated with a functional coating comprising, starting from the substrate: - optionally a first dielectric coating located beneath the functional layer, comprising a layer having a higher refractive index and a layer having a lower refractive index, - a functional layer based on a transparent conductive oxide, - a second dielectric coating located above the functional layer, comprising a layer having a higher refractive index and a layer having a lower refractive index, the layer having a higher refractive index having a higher refractive index than that of the layer having lower refraction, and the variation in refractive index at 550 nm between these two layers being greater than 0.25, the sum of the optical thicknesses of the first and the second dielectric coating being greater than 200 nm.

Description

[0001] Title: Laminated luminous glazing including a functional coating

[0002] The invention relates to the field of luminous glazing. Luminous glazing is glazing that emits light. It comprises a light source and a substrate comprising on one of its main faces a light extracting layer such as a diffusing layer forming a pattern. The light source is optically coupled to the substrate, for example by the edge. The light injected at the edge of the substrate propagates in the substrate by total internal reflection. The substrate acts as a light guide.

[0003] According to the present invention, the mode of propagation of light in the substrate by total internal reflection is called "guided mode". The guided mode therefore corresponds to the use of light at grazing incidence inside a substrate. The critical parameter for the guided mode is the critical angle of total internal reflection. It corresponds to the angle relative to the normal to the substrate above which any light ray arriving on a separation surface or interface, from a medium with a higher optical index to a medium with a lower optical index, is fully reflected by said surface or interface. The critical angle (0c) is determined by applying the Snell-Descartes equation. It corresponds to the angle (in the substrate) for which the light ray is refracted at 90° (in the medium with a lower index than the substrate).

[0004] For luminous glazings, the surrounding medium can be air, another substrate, or a polymeric interlayer. For example, the critical angle of total internal reflection at the interface between a glass substrate with a refractive index of 1.51 and air is approximately 40°. In the case of a glass / polyvinyl butyral (PVB) polymeric interlayer interface, the critical angle is approximately 80°.

[0005] All light rays injected into the substrate having an angle of incidence:

[0006] - above this critical angle are reflected and continue to propagate in the substrate,

[0007] - below this critical angle are partially refracted and gradually leave the substrate.

[0008] In the case of luminous glazing, the light sources used are preferably light-emitting diodes (LEDs in English or DEL in French). The light is extracted at the level of the extractor layer which allows the pattern to be illuminated.

[0009] There is a growing demand for luminous glazing for automotive applications, particularly for car roofs. However, this option is not compatible with most glazing traditionally used for these applications. Indeed, automotive glazing must also have a low-emissivity function to reduce the amount of energy dissipated to the outside. The "low-emissivity" function or property corresponds to the ability of a glazing to prevent heat from escaping by reflecting infrared radiation. For this purpose, functional coatings with infrared (IR) radiation reflection properties are used. In the remainder of the description, the term "functional" describing a coating or layer means "capable of acting on solar radiation and / or infrared radiation".For example, functional coatings comprising a conductive oxide layer placed between two dielectric coatings can be cited. Patent application WO2018 / 206236 is known in particular. This application discloses, starting from the substrate, functional coatings comprising:

[0010] - a dielectric coating comprising dielectric layers such as layers of silicon nitride and / or silicon oxide,

[0011] - a functional layer based on a transparent conductive oxide (TCO) such as a layer based on indium tin oxide (ITO),

[0012] - a dielectric coating comprising dielectric layers such as silicon nitride and silicon oxide layers.

[0013] The absorption of visible light by the functional layers based on conductive oxide in these functional coatings is significant, particularly in the red region. However, the absorption of visible light at normal incidence remains low because the light passes perpendicularly through the functional layer based on conductive oxide. The interaction between the radiation and the functional layer occurs only over the thickness of the functional layer (ef).

[0014] The situation is different for guided mode light. When functional coatings are placed close to the substrate in which the guided mode light propagates, the light propagating in the substrate is likely to interact with the functional layer. The interaction angles between the guided mode light and the substrate are defined directly in the substrate into which the light is injected. The guided mode rays are therefore largely "grazing" (9 greater than 80°) relative to the normal to the substrate in which it propagates.

[0015] A ray of the guided mode therefore crosses the functional layer over a distance corresponding to: Thickness of the functional layer (ef) / cos (9). The more grazing the angle, the lower cos (9), the more the rays of the guided mode interact with the functional layer over a great distance and therefore the greater the proportions of absorbed rays.

[0016] In conclusion, when the substrate in which the light propagates comprises or is in contact with a functional coating, a significant portion of the light comes into contact with this functional coating at a grazing angle and is therefore likely to be absorbed when the functional coating comprises absorbing layers.

[0017] This is why we observe, depending on the injected light, an alteration, a chromatic change, a reduction or even an erasure of the pattern as we move away from the light injection point due to the high absorption in guided mode at grazing angles of the functional layer.

[0018] This problem is particularly pronounced at long wavelengths in the visible range because the absorption of conductive oxide layers, and in particular of ITO, increases with wavelength. In the case of luminous glazing, the optical properties in guided mode of the functional coating are therefore decisive.

[0019] When using light sources emitting red light (red LEDs), the guided mode absorption of wavelengths corresponding to red results in a color (or brightness) that diminishes along the pattern (as one moves away from the light source). When using light sources emitting white light, the guided mode absorption of wavelengths corresponding to red results in a color that alters and a light intensity that diminishes along the pattern.

[0020] The applicant, aware of this phenomenon, was interested in controlling the distribution of electromagnetic energy in the stack by interference effect. The objective is to minimize the energy density at the functional layer level and thus minimize absorption, particularly in the red.

[0021] Indeed, the absorption of light energy in a coating attributable to the presence of a so-called absorbing layer depends both on the thickness and the material constituting it, but also on the position where this layer is located in the coating. In particular, the local amplitude of the electric field at the level of a layer of the coating depends on its position in the coating which functions as an interference filter. The absorption of light energy varies proportionally with respect to the square of the amplitude of this electric field. If the so-called absorbing layer is placed at a location in the coating where the amplitude of the electric field for a given wavelength is low, the absorption of this wavelength will be lower compared to a coating comprising the same absorbing layer placed at a location where the amplitude of the electric field is higher.

[0022] It is possible to selectively increase or reduce the absorption properties of a coating for certain wavelengths. To do this, it is possible to advantageously select the "position" of the absorbing layer by placing it at a location on the coating where the amplitude of the electric field for this wavelength is large or small. To select the most advantageous "position" from the absorption point of view, it is possible to vary the thickness and nature of the dielectric layers of the dielectric coatings surrounding the functional layer.

[0023] The applicant has therefore demonstrated that by selecting the nature and thicknesses of the dielectric layers constituting the dielectric coatings of the functional coatings, it is possible to selectively reduce absorption in the red in guided mode without harming the other properties and functions, in particular low emissivity and aesthetics. To achieve this goal, it was necessary to characterize the absorption by the functional coating of light in guided mode. It is not possible to experimentally determine colorimetric parameters since the guided mode exists only in the substrate. The inventors have determined a specific optical model making it possible to evaluate by simulation the values ​​of a* and b* in reflection in guided mode at the substrate / functional coating interface. This reflection corresponds to an angle of incidence of 80° in the glass substrate. These colorimetric parameters in guided mode are called Rgm, a*gm and b*gm.Rgm corresponds to the total amount of light reflected at each reflection on the layered interface. Lower absorption in the red in the guided mode results in high Rgm values ​​and less negative or even neutral a*gm and b*gm values. A high Rgm parameter denotes low absorption and therefore better preservation of the guided mode in terms of its total intensity.

[0024] Using this model, the applicant has thus succeeded in developing families of solutions meeting these criteria in the form of specific combinations of dielectric layers in dielectric coatings with specific thicknesses and optical indices.

[0025] The present invention therefore relates to a material comprising a substrate coated with a functional coating, intended to be implemented in luminous glazing, having low absorption in guided mode in the visible, particularly in the red when the glazing is illuminated and thus making it possible to avoid any colorimetric drift over the length of the pattern.

[0026] The improvement results from precise control of the optical interference effects between the different layers making up the coating. This control is achieved by choosing the nature, thickness and sequences of dielectric layers constituting the dielectric coatings. This makes functional coatings compatible with use in luminous glazing.

[0027] The invention relates to a material comprising a substrate coated with a functional coating comprising, starting from the substrate:

[0028] - possibly a first dielectric coating located below the functional layer comprising:

[0029] - a layer of higher refractive index with an optical thickness between 0 and 110 nm and

[0030] - a lower refractive index layer with an optical thickness of between 0 nm and 170 nm, the higher refractive index layer, if present, has a higher refractive index than the lower refractive layer, if present, and the variation in refractive index at 550 nm between these two layers is greater than 0.25, greater than 0.30, or greater than 0.40, - a functional layer based on a transparent conducting oxide (TCO),

[0031] - a second dielectric coating located above the functional layer comprising:

[0032] - a layer of higher refractive index with an optical thickness between 80 and 170 nm and

[0033] - a lower refractive index layer with an optical thickness of between 80 and 190 nm, the higher refractive index layer has a higher refractive index than the lower refractive layer and the variation in refractive index at 550 nm between these two layers is greater than 0.25, greater than 0.30, or greater than 0.40, the sum of the optical thicknesses of the first and second dielectric coatings is greater than 200 nm.

[0034] Surprisingly, the best results in terms of low absorption in the red in guided mode, low emissivity and / or neutral aesthetics in transmission are obtained with a functional coating having the following characteristic(s):

[0035] - the functional layer is chosen from fluorine-doped tin oxide, antimony-doped tin oxide and / or indium tin oxide,

[0036] - the functional layer has a geometric thickness between 70 and 200 nm, between 75 and 150 nm, between 80 and 130 or between 90 and 110 nm,

[0037] - the lower refractive index dielectric layers of the dielectric coatings have a refractive index less than 1.7, less than 1.6, or less than 1.5,

[0038] - the lower refractive index layers are silicon oxide-based layers,

[0039] - the higher refractive index dielectric layers of the dielectric coatings have a refractive index greater than 1.9, or greater than 2.0,

[0040] - the dielectric layers with a higher refractive index of each dielectric coating are chosen from:

[0041] - layers based on nitride of one or more elements chosen from silicon, aluminum or zirconium, preferably based on silicon nitride,

[0042] - layers based on zinc and tin oxide,

[0043] - zinc oxide-based layers or

[0044] - layers based on titanium oxide,

[0045] - the dielectric layers of lower refractive index of the dielectric coatings are identical or different and are chosen from silicon oxide-based layers,

[0046] - the dielectric layers of higher refractive index of the dielectric coatings are identical or different and are chosen from layers based on silicon nitride or zinc and tin oxide.

[0047] The applicant has in particular highlighted two particularly advantageous combinations having particular ranges of optical thickness for each dielectric layer of the dielectric coatings. This means that by choosing a functional coating satisfying one of these combinations of ranges, it is possible to obtain a certain number of the advantageous properties sought by the invention. However, any selection within these combinations does not make it possible to obtain all the preferred properties of the invention.

[0048] According to a first preferred combination, the invention relates to a material of which: the dielectric coating located below the functional layer comprises:

[0049] - a layer of higher refractive index with an optical thickness between 0 nm and 20 nm,

[0050] - a lower refractive index layer with an optical thickness of between 0 nm and 25 nm, preferably 10 and 20 nm, the dielectric coating located above the functional layer comprises:

[0051] - a layer with a higher refractive index and an optical thickness between 100 nm and 140 nm,

[0052] - a layer of lower refractive index with an optical thickness between 80 and 140 nm.

[0053] According to the invention, the lower bound in the ranges "between 0 nm" means that the layer may be absent. The bound is therefore included.

[0054] According to another preferred combination, the invention relates to a material of which: the dielectric coating located below the functional layer comprises:

[0055] - a layer of higher refractive index with an optical thickness between 40 nm and 110 nm or between 60 nm and 80 nm,

[0056] - a lower refractive index layer with an optical thickness of between 20 nm and 145 nm or between 75 nm and 105 nm, the dielectric coating located above the functional layer comprises:

[0057] - a layer with a higher refractive index and an optical thickness between 80 nm and 170 nm or between 90 nm and 130 nm,

[0058] - a layer of lower refractive index with an optical thickness between 125 and 190 nm or between 150 and 165 nm.

[0059] According to this advantageous combination, the sum of the optical thicknesses of the first and second dielectric coatings is greater than 300 nm, 350 nm, 380 nm or 400 nm.

[0060] The invention advantageously presents colors in reflection at 60° which are not very intense.

[0061] The invention also relates to laminated glazing comprising a material according to the invention and at least one second substrate, the material and the second substrate being bonded together by means of a lamination interlayer.

[0062] Conventionally, the faces of a glazing unit are designated from the outside by numbering the faces of the substrates from the outside to the inside of the passenger compartment or room it equips. This means that incident sunlight passes through the faces in ascending order of their number.

[0063] In the case of laminated glazing, all the faces of the substrates are numbered but the faces of the lamination interlayers are not numbered.

[0064] The laminated glazing according to the invention comprises a face 1 located outside the building or vehicle it equips, faces 2 and 3 in contact with the lamination interlayer and a face 4 inside the building or vehicle. The functional coating is preferably positioned on face 4.

[0065] The invention also relates to:

[0066] - laminated glazing according to the invention mounted on a vehicle or on a building, and

[0067] - the use of laminated glazing according to the invention as low-emissivity glazing for buildings or vehicles,

[0068] - a building, a vehicle comprising glazing according to the invention.

[0069] The laminated glazing according to the invention is preferably automotive glazing such as automotive roof glazing.

[0070] The laminated glazing according to the invention may comprise curved substrates.

[0071] Laminated glazing may have a light transmission of less than 50%, less than 30%, less than 20% or less than 10%.

[0072] Laminated glazing can also have a light transmission greater than 60%, greater than 70%, or greater than 80%.

[0073] The invention also relates to a luminous glazing comprising a laminated glazing according to the invention, a light source optically coupled to form a light guide and a light extractor element for extracting the guided light.

[0074] The light source is preferably peripheral.

[0075] The light source is preferably optically coupled to the substrate of the material according to the invention. The optical coupling can be done:

[0076] - by the edge of the substrate of the material of the invention,

[0077] - by a wall delimiting a hole, preferably through, the substrate of the material, or

[0078] - by redirecting the light for example, the source can be located on the F4 side (offset or opposite the F4 face) and a light redirecting element such as a prismatic reflective film is positioned on the F3 side.

[0079] The light extracting element preferably a diffusing element in particular a diffusing element in a layer forming a pattern.

[0080] The luminous glazing of the invention may be chosen from a side window, a rear window, a roof window or a windshield. The preferred characteristics which appear in the remainder of the description are applicable both to the material according to the invention and, where appropriate, to the glazing, the method, the use, the building or the vehicle according to the invention.

[0081] All the luminous characteristics described are obtained according to the principles and methods of the ISO 9050 standard relating to the determination of the luminous and solar characteristics of glazing used in glass for construction.

[0082] Conventionally, refractive indices are measured at a wavelength of 550 nm.

[0083] According to the invention, two elements such as layers or substrates have substantially equal refractive indices, when the absolute value of the difference between the refractive indices of the two materials constituting said layers or substrates at 550 nm is less than or equal to 0.15.

[0084] The layers of higher refractive index and the layers of lower refractive index have different refractive indices. According to the invention, two elements such as layers or substrates have different refractive indices, when the absolute value of the difference between the refractive indices of the two materials constituting said layers or substrates at 550 nm is greater than or equal to 0.25, greater than 0.30, greater than 0.40, greater than 0.50, greater than 0.60, greater than 0.70 or greater than 0.80.

[0085] The refractive indices are defined at the wavelength of 550 nm.

[0086] Unless otherwise stated, the thicknesses mentioned in this document without further details are physical, real or geometric thicknesses called Ep and are expressed in nanometers (and not optical thicknesses). The optical thickness Eo is defined as the physical thickness of the layer considered multiplied by its refractive index at the wavelength of 550 nm: Eo = n*Ep. Since the refractive index is a dimensionless value, the unit of optical thickness can be considered to be that chosen for the physical thickness.

[0087] According to the invention, a dielectric coating corresponds to a sequence of dielectric layers, located between the substrate and the functional layer, or above the functional layer.

[0088] If a dielectric coating is composed of several dielectric layers, the optical thickness of the dielectric coating corresponds to the sum of the optical thicknesses of the different dielectric layers constituting the dielectric coating.

[0089] The functional coating is deposited by magnetic field-assisted sputtering (magnetron process). According to this advantageous embodiment, all layers of the coatings are deposited by magnetic field-assisted sputtering. Unless otherwise specifically stated, the expressions "above" and "below" do not necessarily mean that two layers and / or coatings are arranged in contact with each other. When it is specified that a layer is deposited "in contact" with another layer or coating, this means that there cannot be one (or more) layer(s) intercalated between these two layers (or layer and coating).

[0090] In this description, unless otherwise indicated, the expression "based on", used to qualify a material or a layer as to what it contains, means that the mass fraction of the constituent that it comprises is at least 50%, in particular at least 70%, preferably at least 90%.

[0091] According to the invention:

[0092] - light reflection corresponds to the reflection of solar radiation in the visible part of the spectrum,

[0093] - light transmission corresponds to the transmission of solar radiation in the visible part of the spectrum,

[0094] - light absorption corresponds to the absorption of solar radiation in the visible part of the spectrum.

[0095] The luminous characteristics are measured according to illuminant D65 at 2° perpendicular to the material mounted in single glazing (unless otherwise indicated):

[0096] - TL corresponds to the light transmission in the visible in %,

[0097] - Rc corresponds to the external light reflection in the visible in %, observer on the functional coating side, ,

[0098] - Rs corresponds to the interior light reflection in the visible in %, observer side opposite to that including the functional coating, ,

[0099] - a*T and b*T correspond to the transmission colors a* and b* in the L*a*b* system,

[0100] - a*Rc and b*c correspond to the colors in reflection a* and b* in the L*a*b* system, observer on the functional coating side, ,

[0101] - a*Rs and b*Rs correspond to the reflection colors a* and b* in the L*a*b* system, observer side opposite to that including the functional coating.

[0102] The parameters a*60° and b*60° correspond to the colours a* and b* in the L*a*b* system at an angle of 60° relative to the normal to the plane of the glazing measured according to illuminant D65 at 2° perpendicular to the material mounted in single glazing with the functional coating positioned on face 1, observer on the functional coating side.

[0103] The materials according to the invention make it possible to obtain on a clear glass substrate (single glazing): ,

[0104] - an emissivity of less than 30%, or even less than 20%, and / or,

[0105] - a low Rs reflection, notably less than 7%, and,

[0106] - neutral colors in reflection and, ,

[0107] - low colors in angular reflection resulting in a reflection at 60° of less than 17% and neutral colors. Preferably, the material gives the glazing incorporating it colors in transmission and in external reflection or in internal reflection (single glazing) as defined below:,

[0108] - values ​​of a*Rc between -8 and 4, between -2 and 2, between -2 and 1.5, and / or,

[0109] - b*Rc values ​​between -5 and +5, between -2 and 2, and / or,

[0110] - values ​​of a*Rc 60° between -8 and 6, between -2 and 1.5, and / or

[0111] - b*Rc 60° values ​​between -8 and 8, between -2 and 2.

[0112] These properties are measured on ordinary clear glass. Ordinary clear glass 4 to 6 mm thick has the following luminous characteristics:

[0113] - a light transmission between 87 and 91.5%,

[0114] - a light reflection of between 7 and 9.5%,

[0115] - a light absorption of between 0.3 and 5%.

[0116] The parameters Rgm, a*gm and b*gm correspond to the reflection and the a* and b* colors in guided mode reflection at the substrate / functional coating interface at an angle of 80° in the glass substrate.

[0117] In laminated glazing configurations, the colorimetric properties are calculated with:

[0118] - materials comprising a substrate coated with a functional coating mounted in laminated glazing,

[0119] - the laminated glazing comprises a material comprising a 2mm ordinary soda-lime glass substrate and another 2mm soda-lime glass substrate, the two substrates are separated by a 0.76mm Polyvinyl Butyral (PVB) lamination interlayer,

[0120] - the functional covering is preferably positioned on face 4.

[0121] The functional coating preferably comprises a single functional layer.

[0122] Preferably, the functional coating is deposited on a flat glass and the whole is curved and tempered. This improves the emissivity of a TCO such as ITO in particular. The functional coating can also be heated during deposition.

[0123] The dielectric layers are conventionally chosen from oxide-based, nitride-based or oxynitride-based layers. The oxide-based layers of one or more elements comprise essentially oxygen and very little nitrogen. The oxide-based layers comprise in particular at least 90% by atomic percentage of oxygen relative to the oxygen and nitrogen in said layer. The nitride-based layers comprise essentially nitrogen and very little oxygen. The nitride-based layers comprise at least 90% by atomic percentage of nitrogen relative to the oxygen and nitrogen in said layer. The oxynitride-based layers comprise a mixture of oxygen and nitrogen. The oxynitride-based layers comprise 10 to 90% (limits excluded) by atomic percentage of nitrogen relative to the oxygen and nitrogen in said layer.

[0124] The amounts of oxygen and nitrogen in a layer are determined as atomic percentages relative to the total amounts of oxygen and nitrogen in the layer under consideration.

[0125] The dielectric layers are classically chosen from:

[0126] - layers comprising silicon, aluminum and / or zirconium, optionally doped with at least one other element,

[0127] - layers based on zinc and tin oxide,

[0128] - layers based on titanium oxide,

[0129] - zinc oxide-based layers.

[0130] The silicon-comprising layers comprise at least 50% by mass of silicon relative to the mass of all elements constituting the silicon-comprising layer other than nitrogen and oxygen.

[0131] The layers comprising silicon may be selected from oxide-based, nitride-based or oxynitride-based layers such as silicon oxide-based layers, silicon nitride-based layers and silicon oxynitride-based layers.

[0132] The silicon oxide-based layers comprise at least 90 atomic percent oxygen relative to the oxygen and nitrogen in the silicon oxide-based layer. The silicon nitride-based layers comprise at least 90 atomic percent nitrogen relative to the oxygen and nitrogen in the silicon nitride-based layer. The silicon oxynitride-based layers comprise 10 to 90 atomic percent nitrogen relative to the oxygen and nitrogen in the silicon oxide-based layer. Preferably, the silicon oxide-based layers are characterized by a refractive index at 550 nm of less than or equal to 1.55. Preferably, the silicon nitride-based layers are characterized by a refractive index at 550 nm of greater than or equal to 1.95.

[0133] The layers comprising silicon may comprise or consist of elements other than silicon, oxygen and nitrogen. These elements may be selected from aluminum, boron, titanium, and zirconium. The layers comprising silicon may comprise at least 2%, at least 5% or at least 8% by mass of aluminum relative to the mass of all elements constituting the layer comprising silicon other than oxygen and nitrogen.

[0134] The layers comprising aluminum may be chosen from oxide-based, nitride-based or oxynitride-based layers such as aluminum oxide-based layers such as AI2O3, aluminum nitride-based layers such as AIN and aluminum oxynitride-based layers such as AlOxNy. Among the dielectric layers, a distinction is made, depending on their refractive index at 550 nm, between low refractive index layers, intermediate refractive index layers and high refractive index layers. The low refractive index layers have a refractive index of less than 1.70. The intermediate refractive index layers have a refractive index of between 1.70 and 2.2. The high refractive index layers have a refractive index greater than 2.2.

[0135] The low index layers may have a refractive index less than 1.70, less than 1.6 or less than 1.5. The low index layers are preferably silicon oxide-based layers.

[0136] The intermediate refractive index layers can be chosen from:

[0137] - zinc oxide-based layers (n550 = 2.0),

[0138] - layers based on tin oxide (n550 = 2.0),

[0139] - layers based on zinc and tin oxide (n550 = 2.0),

[0140] - layers based on silicon and / or aluminum nitride (n550 = 2.1),

[0141] - layers based on silicon and / or aluminum oxynitride.

[0142] High refractive index layers can have a refractive index:

[0143] - greater than 2.30, greater than 2.35 or greater than 2.40.

[0144] - less than 2.60, less than 2.50, less than 2.40.

[0145] High refractive index layers can be chosen from:

[0146] - layers based on titanium oxide (n550=2.4),

[0147] - layers based on mixed titanium oxide and another component chosen from the group consisting of Zn, Zr and Sn,

[0148] - layers based on a layer of zirconium nitride,

[0149] - layers based on silicon and zirconium nitride (n550 nm = 2.20 - 2.40),

[0150] - layers based on a layer of zirconium oxide,

[0151] - layers based on manganese oxide MnO (n550 = 2.16),

[0152] - layers based on a layer of tungsten oxide (n550 = 2.15),

[0153] - layers based on a layer of niobium oxide (n550 = 2.30),

[0154] - layers based on a layer of bismuth oxide (n 550 = 2.60).

[0155] The lower refractive index layer can be chosen from the low refractive index layers. In this case, the higher refractive index layers are chosen from the layers having a refractive index greater than 1.7. They are therefore chosen from the intermediate refractive layers and the high refractive index layers.

[0156] The lower refractive index layer may be selected from the intermediate refractive index layers. In this case, the higher refractive index layers are selected from the high refractive index layers. The sum of the physical thicknesses of all the layers comprising silicon of each dielectric coating is greater than 50%, 60% or 70% of the total thickness of the dielectric coating considered.

[0157] The substrates may be mineral glass or transparent polymer material substrates. The substrates are preferably mineral glass.

[0158] The mineral glass substrates that make up the glazing can be soda-lime, aluminosilicate or borosilicate glass.

[0159] The substrates can be made of transparent polymeric material which include poly(methyl methacrylate) (PMMA), polycarbonate (PC), polyurethane or polyurea (PU) substrates.

[0160] Preferably, the lamination interlayers comprise one or more sheets of organic polymers.The organic polymers are selected from polyvinyl butyral (PVB), polyurethanes (PU), polyureas, ethylene vinyl acetate (EVA), polyolefins (including polyethylene (PE), polypropylene (PP) or polyisobutylene (P-IB)), polyvinyl chloride and its derivatives (e.g. poly(vinyl dichloride) (PVDC)), styrenic polymers (e.g. polystyrene (PS), acrylostyrene butadiene (ABS), styrene acrylonitrile (SAN)), polyacrylics (including polyacrylonitrile (PAN) and poly(methyl methacrylate) (PMMA)), polyesters (including poly(ethylene terephthalate) (PET) and poly(butylene terephthalate) (PBT)), polyoxymethylene (POM), polyamides (PA), fluorinated polymers such as polychlorotrifluoroethylene (PCTFE), polycarbonates (PC), aromatic polysulfones including polysulfone (PSU), polyphenylene ether (PPE), epoxy (EP) alone or as a mixture and / or copolymer of several of them. The lamination interlayer can be tinted.

[0161] Preferably the substrate material is clear and better extra clear to limit absorption.

[0162] The substrate can be an ultra-thin glass, for example with a thickness of less than 0.7 mm.

[0163] The substrate can be thermally tempered glass.

[0164] The invention also relates to a luminous glazing comprising a laminated glazing according to the invention, a light extracting element, preferably a layered diffusing element and light sources.

[0165] The layered diffusing element may be in contact or formed on the face of a substrate of the laminated glazing by a surface treatment such as sandblasting, by acid etching, or by depositing a diffusing layer.

[0166] Examples of diffusing layered elements include acid-etched glass, Satinovo® glass from SAINT-GOBAIN GLASS, and glass with the Smoothlite® diffusing layer from SAINT-GOBAIN GLASS. The diffusing layered element may be formed in the mass of a substrate or interlayer, for example, by a laser engraving type treatment. The diffusing layered element in the form of a substrate or interlayer is then attached to the surface of the substrate of the material according to the invention, for example by lamination.

[0167] The layered diffusing element can be placed on the substrate of the material according to the invention, in particular on the face opposite that of the functional coating.

[0168] The layered diffusing element may be a self-supporting diffusing film, preferably bonded to a glazing substrate.

[0169] The layered diffusing element may be a layer deposited on a substrate. The layer may be based on a diffusing enamel. It may be deposited discontinuously on one side of a substrate so as to form a pattern. The layer may be a diffusing ink printed on a substrate or an interlayer.

[0170] The diffusing layer may comprise an organic or mineral matrix and diffusing particles, for example of a metal oxide such as titanium dioxide. As an example of a transparent mineral diffusing layer, mention may be made of transparent enamel as described in application FR3084355. As an example of an organic transparent diffusing layer, mention may be made of the transparent layer as described in application WO2022023638.

[0171] The diffusing elements are placed at the desired light extraction points. This makes it possible to design the path of light on the surface of the glazing by diffusing it through diffusing surfaces with well-defined areas and contours, for example according to geometric patterns or even text.

[0172] The layered diffusing element can be opaque or transparent.

[0173] The diffusing layer may comprise a matrix (organic or mineral) and diffusing particles, for example of metal oxide (TiO2 etc.).

[0174] As an example of a transparent mineral diffusing layer, we can cite the transparent enamel as described in application FR3084355

[0175] As an example of an organic transparent diffusing layer, mention may be made of the transparent layer as described in application WO2022023638

[0176] The laminated glazing may include a masking layer of opaque material (particularly black) preferably on the main internal face (interlayer side) of the second substrate (face 2). This peripheral layer forms a frame and defines a clear view. Preferably, the light source is masked from the outside in particular by the masking layer. This layer may be an enamel located on the second glass substrate or an ink located on the interlayer.

[0177] The light source capable of emitting light is preferably an electroluminescent element such as light-emitting diodes (LEDs in English or DEL in French). The light source can be polychromatic (white light) or monochromatic, particularly red.

[0178] The light source can be linear such as a strip of diodes.

[0179] The light source can be coupled directly to the substrate material or via a guide, collimating optics

[0180] The light source is preferably optically coupled to the substrate of the material according to the invention. The optical coupling can be done:

[0181] - by the edge of the substrate of the material of the invention,

[0182] - by a wall delimiting a hole, preferably through, the substrate of the material, or

[0183] - by redirecting the light for example, the source can be located on the F4 side (offset or opposite the F4 face) and a light redirecting element such as a prismatic reflective film is positioned on the F3 side.

[0184] The light source may be located opposite or near the edges of the substrate to be coupled through the edge of the substrate. Reference may be made to patent application WO2010049638.

[0185] The light source can also be placed in a hole made in the glazing (circular or oblong). Reference can be made to patent applications WO2013110885 and WO2018178591.

[0186] The light source may be located nearby, for example on face 4 (offset or opposite face 4) and a light redirecting element such as a reflective prismatic film is positioned to redirect the light (for example on face 3). Reference may be made to patent application WO2022096365.

[0187] Multiple light sources can be used, for example near opposite edges of the substrate.

[0188] Diodes can be front- or side-emitting. Diodes are preferably surface-mounted components on a substrate with electrically conductive tracks, such as a printed circuit card, for example a rectangular substrate.

[0189] When the glazing is used as a rear window, the light source preferably emits in the red range. When the glazing is used as a rear window or windshield, the pattern may be a pictogram such as an emergency triangle. Example

[0190] I. Materials and coatings

[0191] In these examples, the glass substrates are aluminosilicate glass substrates. The lamination interlayers are 0.76 mm Poly(vinyl butyral) (“PVB”) interlayers.

[0192] Functional layers (F) are layers of indium tin oxide.

[0193] Dielectric coatings include:

[0194] - layers based on silicon nitride (Si3N4, n550 = 2.0),

[0195] - layers based on silicon oxide (SiO2, n550 = 1.5).

[0196] The deposition conditions of the layers, which were deposited by sputtering (so-called “magnetron cathode sputtering”), are summarized in Table 1.

[0197] [Table 1]

[0198] Table 2 lists the materials and physical thicknesses in nanometers (unless otherwise indicated) of each layer or coating that constitutes the coatings according to their position relative to the substrate carrying the stack (last line at the bottom of the table).

[0199] [Table 2] D: Dielectric coating; CF: Functional layer; Eg: Geometric thickness; Eo: Optical thickness; Ep: Thickness. II. Illustration of the attenuation phenomenon

[0200] Figures 1 and 2 each represent photographs of luminous glazings illuminated respectively from above by blue (figure 1) and red (figure 2) light-emitting diodes. In each photograph, the glazing located on the left comprises a functional coating of the prior art Cp-2 and the glazing located on the right does not comprise a functional coating.

[0201] When blue LEDs are used, the pattern is visible on both panes of glass. However, the pattern remains less bright when the glass also has a functional coating.

[0202] When red diodes are used, the pattern quickly becomes invisible on the left window.

[0203] Figure 3 shows a photograph of a luminous glazing unit comprising a functional coating of the prior art Cp-2 illuminated from above and in the center by white light-emitting diodes (element S). It comprises a diffusing layer in the form of points. The light is injected from above and extracted along the propagation path by the diffusion points. In this photograph, it can be seen that only the twelve framed points (element A) appear white. All the others appear cyan, a color that oscillates between blue and green, with an increasing blue-green intensity as a function of the distance from the injection point.

[0204] III. Characterization of the absorption effect in guided mode

[0205] The Rgm, a*gm and b*gm values ​​in guided mode reflection at the substrate / functional coating interface were determined. This reflection corresponds to an incidence angle of 80° in the glass substrate.

[0206] By definition of the guided mode, whose propagation angle is greater than the value of the critical angle of the system, light cannot be transmitted through the coating. What is not reflected is therefore absorbed.

[0207] According to the invention, it is very useful to have the highest possible Rgm because this parameter denotes low absorption. Indeed, the conservation of the energy of a guided mode imposes Rgm + Agm = 1, with Agm the absorption of the guided mode. Low absorption results in high values ​​of Rgm. A high value of Rgm translates both lower absorption, particularly in the red in guided mode, and better preservation of the guided mode in terms of its total intensity.

[0208] The parameters a*gm and b*gm indicate the change in colorimetric parameters of the light upon reflection, for white incident light, such as H'illuminant D65. A positive a*gm means that the reflection becomes redder than the incident ray.

[0209] A negative a*gm means that the reflection becomes greener than the incident ray.

[0210] A positive b*gm means that the reflection becomes more yellow than the incident ray.

[0211] A negative b*gm means that the reflection becomes bluer than the incident ray.

[0212] A reflection of a certain color indicates light absorption of the complementary color. So, for example, a negative a*gm is synonymous with green reflection and absorption in red.

[0213] The higher the absolute value of the a* and b* parameters, the more pronounced the color of the reflections / absorptions will be.

[0214] According to the invention, less negative, or even neutral, values ​​of a*gm and b*gm are sought. A functional coating is particularly suitable for use in luminous glazing if:

[0215] - the values ​​of a*gm are between -4 and 2, and

[0216] - b*gm values ​​are greater than -2.

[0217] However, this should be balanced with the Rgm values. As explained above, a high Rgm denotes low absorption. This is why it may be interesting to have structures with high Rgm values ​​even if the associated a*gm and b*gm are higher in absolute value because these colors will be less intense.

[0218] Table 4 summarizes the optical properties.

[0219] [Table 4]

[0220] The prior art coatings of type Cp.1 and Cp.2 cannot be used in luminous glazing because they do not have a sufficiently stable color in the substrate in guided mode. The Rgm values ​​are lower than the Rgm values ​​of the examples according to the invention. In addition, they have too negative a*gm and b*gm values.

[0221] This explains why when the light source is a red light, we quickly observe an extinction of this red light the further we move away from the light injection points (Figure 2, left photograph).

[0222] The functional coatings of the invention have: - Ex.1, Ex.2 and Ex.4: very high Rgm values ​​and a*gm and b*gm values ​​less negative than those of Cp.1 and Cp.2,

[0223] - Ex.3 and Ex.5: high Rgm values ​​and neutral a*gm and b*gm values.

[0224] IV. Configurations

[0225] Figure 4 illustrates a luminous laminated glazing according to the invention. It comprises:

[0226] - a material according to the invention (1) comprising a functional coating (2) located on the face 4 of the laminated glazing,

[0227] - a lamination interlayer preferably in PVB (3),

[0228] - a second glass substrate (4),

[0229] - a diffusing element in a layer forming a pattern (5),

[0230] - a light source capable of injecting light into the substrate.

Claims

Demands 1. Material comprising a substrate coated with a functional coating comprising, starting from the substrate: - possibly a first dielectric coating located below the functional layer comprising: - a layer with a higher refractive index and an optical thickness between 0 and 110 nm and - a layer with a lower refractive index and an optical thickness between 0 nm and 170 nm, the layer with a higher refractive index, if present, has a higher refractive index than the lower refractive index layer, if present, and the variation in refractive index at 550 nm between these two layers is greater than 0.25, - a functional layer based on a transparent conductive oxide, - a second dielectric coating located above the functional layer comprising: - a layer with a higher refractive index and an optical thickness between 80 and 170 nm and - a lower refractive index layer with an optical thickness between 80 and 190 nm, the higher refractive index layer has a higher refractive index than the lower refractive index layer and the variation in refractive index at 550 nm between these two layers is greater than 0.25, the sum of the optical thicknesses of the first and second dielectric coating is greater than 200 nm.

2. Material according to claim 1 characterized in that the functional layer is selected from fluorine-doped tin oxide, antimony-doped tin oxide and / or indium tin oxide.

3. Material according to any one of the preceding claims characterized such that the lower refractive index dielectric layers of the dielectric coatings have a refractive index less than 1.

7.

4. Material according to the preceding claim characterized in that the lower refractive index layers are silicon oxide based layers.

5. Material according to any one of the preceding claims characterized such that the higher refractive index dielectric layers of the dielectric coatings have a refractive index greater than 1.

9.

6. Material according to any one of the preceding claims characterized in that the dielectric layers of higher refractive index of each coating dielectrics are chosen from: - Nitride-based layers of one or more elements selected from silicon, aluminum or zirconium, preferably silicon nitride-based, - zinc and tin oxide-based coatings, - zinc oxide-based or - titanium oxide-based coatings.

7. Material according to any one of the preceding claims characterized in that: the dielectric coating located below the functional layer comprises: - a layer with a higher refractive index and an optical thickness between 0 nm and 20 nm, - a layer with a lower refractive index and an optical thickness between 0 nm and 25 nm; the dielectric coating located above the functional layer comprises: - a layer with a higher refractive index and an optical thickness between 100 nm and 140 nm, - a layer with a lower refractive index and an optical thickness between 80 and 140 nm.

8. Material according to any one of claims 1 to 6 characterized in that the dielectric coating located below the functional layer comprises: - a layer with a higher refractive index and an optical thickness between 40 nm and 110 nm, - a layer with a lower refractive index and an optical thickness between 20 nm and 145 nm; the dielectric coating located above the functional layer comprises: - a layer with a higher refractive index and an optical thickness between 80 nm and 170 nm, - a layer with a lower refractive index and an optical thickness between 125 and 190 nm.

9. Material according to the preceding claim characterized such that the sum of the optical thicknesses of the first and second dielectric coating is greater than 300 nm.

10. Material according to claim 8 or 9 characterized in that: the dielectric coating located below the functional layer comprises: - a layer with a higher refractive index and an optical thickness between 60 nm and 80 nm, - a layer with a lower refractive index and an optical thickness between 75 nm and 105 nm; the dielectric coating located above the functional layer comprises: - a layer with a higher refractive index and an optical thickness between 90 nm and 130 nm, - a layer with a lower refractive index and an optical thickness between 150 and 165 nm.

11. Laminated glazing comprising a material according to any one of claims 1 to 10 and at least a second substrate, the material and the second substrate are bonded together via a lamination interlayer.

12. Laminated glazing according to the preceding claim characterized in that it comprises a face 1 located outside the building or vehicle which it equips, faces 2 and 3 in contact with the lamination interlayer and a face 4 inside the building or vehicle, the functional coating is positioned on face 4.

13. Luminous glazing comprising laminated glazing according to any one of claims 11 to 12, a light source optically coupled to form a light guide and a light extractor element to extract the guided light.

14. Luminous glazing according to the preceding claim characterized in that the extracting element is a diffusing layer forming a pattern.

15. Illuminated glazing according to the preceding claim selected from a side window, a rear window, a roof window or a windscreen.

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