Luminous glazing unit

Abstract

The present invention relates to a luminous glazing unit comprising: - a first substrate coated with a functional coating, the substrate comprising two faces and an edge; - a light source comprising an emitting surface optically coupled to the substrate such that the light enters the substrate through an entry face and the substrate forms a light guide; ‐ a light extractor element for extracting the light and forming a light pattern; the glazing unit being characterised in that it comprises at least one light polariser located between the emitting surface of the light source and the face through which the light enters the substrate.

Description

[0001] LUMINOUS GLAZING

[0002] TECHNICAL FIELD OF THE INVENTION

[0003] The technical field of the invention is that of luminous or illuminating 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 element 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. We therefore refer to the "guided mode".

[0004] The invention finds a particularly advantageous application in the production of glazing for vehicles or buildings.

[0005] INTRODUCTION

[0006] 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).

[0007] For luminous glazing, 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) polymer interlayer interface, the critical angle is approximately 80°. Any light rays injected into the substrate having an angle of incidence:

[0008] - above this critical angle are reflected and continue to propagate in the substrate,

[0009] - below this critical angle are partially refracted and gradually leave the substrate.

[0010] In the case of luminous glazing, the light sources used are preferably inorganic light-emitting diodes ("LEDs" in English as opposed to "OLEDs"). The light is extracted at the extraction layer, which makes it possible to form a light pattern.

[0011] TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0012] It is known to integrate inorganic light-emitting diodes, also called LEDs or LEDs for "Light-Emitting Diodes", at the edge of simple or laminated glazing, so that the light emitted by the diodes enters through the edge of a sheet of glass and is guided by the latter to a diffusing element, also called a light extracting layer. Reference may be made to patent application WO2010049638.

[0013] These luminous glazings essentially have an ambient lighting or light signaling function which is achieved with low-power diodes. The luminous efficiency of such edge-lit glazings is generally limited due to light losses due to the absorption of light by the glass serving as a waveguide and / or the materials near it.

[0014] It is also known, in particular from documents WO 2013 / 110885 and WO 2018 / 178591, to drill a hole in the glass sheet and to arrange the diodes therein. This hole is made close to the extraction means in particular so as to shorten the optical path traveled by the light between the diodes and the extraction means. It is thus possible to reduce losses linked to the absorption of light.

[0015] The light emitted by the diodes is injected into the glass sheet through an additional slice formed by the hole. The light then bounces between the two main faces of the glass sheet until it reaches the extractor element.

[0016] These luminous glazings do not have a functional coating (low emissivity, solar protection or absorption). There are many applications where the glazing has a functional coating. In the remainder of the description, the term "functional" describing a coating or a layer means "capable of acting on solar radiation and / or infrared radiation".

[0017] It can be a coating with low emissivity, absorption, or solar control functions.

[0018] The "low emissive" 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.

[0019] The "solar control" function or property corresponds to the ability of a glazing to reduce the heat input due to solar radiation, while maximizing the input of visible light. This ability is also provided by the addition of a functional coating to the glazing that reflects infrared radiation, on the same principle as the low-emissivity function.

[0020] Glazing with functional coating is used both for automotive applications, for example for car roofs, and for building applications.

[0021] There is a growing demand for luminous glazing. This can be single, double, or laminated glazing.

[0022] As a coating that can act on solar radiation, we can also mention functional coatings comprising a layer that absorbs visible radiation.

[0023] As IR-reflecting functional coatings, examples that may be mentioned are functional coatings comprising a conductive oxide layer disposed between two dielectric coatings, as described in patent application WO2018 / 206236. This application discloses, starting from the substrate, functional coatings comprising:

[0024] - a dielectric coating comprising dielectric layers such as layers of silicon nitride and / or silicon oxide,

[0025] - a functional layer based on a transparent conductive oxide (TCO) such as a layer based on indium tin oxide (ITO), - a dielectric coating comprising dielectric layers such as layers of silicon nitride and silicon oxide.

[0026] 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.

[0027] The situation is different for light in guided mode. As explained above, the "guided mode" is the mode of propagation of light in the substrate by total internal reflection.

[0028] When functional coatings are placed close to the substrate in which the light propagates in guided mode, the light propagating in the substrate is likely to interact with the functional layer. The interaction angles between the light of the guided mode and the substrate are defined directly in the substrate into which light is injected. The rays of the guided mode are therefore largely "grazing" (0 greater than 80°) relative to the normal to the substrate in which it propagates.

[0029] A ray of the guided mode therefore crosses the functional layer over a distance corresponding to: Thickness of the functional layer (ef) / cos (0). The more grazing the angle, the lower cos (0), 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.

[0030] 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 absorbent layers. This is why, depending on the injected light, we observe 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. This problem is particularly marked at long wavelengths in the visible range because the absorption by the conductive oxide layers and in particular ITO increases with the wavelength. In the case of luminous glazing, the optical properties in guided mode of the functional coating are therefore decisive.

[0031] This phenomenon is not limited to functional coatings comprising conductive oxide layers but can also occur for other functional coatings, such as absorbent or solar control coatings.

[0032] 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.

[0033] SUMMARY OF THE INVENTION

[0034] The present invention aims to remedy at least one of the drawbacks which have just been mentioned.

[0035] According to the invention, this aim is achieved by providing luminous glazing comprising:

[0036] - a first substrate coated with a functional coating (5), said substrate comprising two faces and a wafer (8);

[0037] - a light source (7) comprising an emitting surface, optically coupled with the substrate such that the light enters the substrate through an entry face and the substrate forms a light guide;

[0038] - a light extracting element (6) for extracting the light and forming a light pattern; the glazing being characterized in that it comprises at least one light polarizer located between the emitting surface of the light source (7) and the light entry face in the substrate.

[0039] This is therefore the guided mode in which the light injected into the substrate propagates in the substrate by total internal reflection, forming a guided light beam. A polarizer is an optical instrument well known to those skilled in the art. It filters, in an incident light wave, a preferential polarization direction. The polarizer is, for example, in the form of a semi-transparent plastic film or sheet. Polarizers are available on the market, for example from Techspec or 3M brands.

[0040] In the context of the invention, the term "transparent" means that the light transmission in the visible range is greater than 50%. However, in applications where visibility through the glazing is not a determining factor, the light transmission may be much lower, for example greater than 5%.

[0041] Throughout the description and in the claims, "substantially orthogonal" means an angle between 85° and 95°.

[0042] According to one embodiment of the invention, the light entry face into the substrate is the edge (8) of the substrate.

[0043] According to another embodiment of the invention, the substrate comprises a hole and the light entry face into the substrate is a wall delimiting the hole.

[0044] Preferably, the light source (7) is an inorganic light-emitting diode (LED).

[0045] In the illuminating glazing of the present invention, preferably, a large number of diodes, for example at least three, preferably at least five and more preferably at least ten diodes are placed opposite the light entry face (or faces) of the waveguide.

[0046] The entrance face can be:

[0047] - spaced from the polarizer, in particular by several centimeters, by at most 10 mm, by at most 5 mm or by at most 1 mm, or

[0048] - in optical contact with the polarizer by glue or

[0049] - in physical contact with the polarizer.

[0050] The polarizer can be:

[0051] - spaced from the light-emitting surface, in particular by several centimeters, by at most 10 mm, by at most 5 mm or by at most 1 mm, or

[0052] - in optical contact with the emitting surface, by a glue or

[0053] - in physical contact with the emitting surface.

[0054] According to preferred embodiments of the invention, the polarizer (9) is bonded to the emitting surface of the light source (7) or bonded to the light entry face in the substrate. According to a preferred embodiment of the invention, the substrate is coated with a low-emissivity functional coating (5), in particular comprising a transparent conductive oxide layer. Such conductive layers are known as TCO ("transparent conductive oxide"), they can be composed of mixed indium and tin oxide (ITO), fluorine-doped tin oxide or antimony-doped tin oxide.

[0055] According to one embodiment of the invention, the polarizer is of type S.

[0056] According to another embodiment of the invention, the polarizer is of type P.

[0057] The type of polarizer, S or P, must be chosen according to the coating present on the substrate.

[0058] According to a particular embodiment, the coating has low-emissive properties, for example a coating comprising a TCO layer and the polarizer is of type S.

[0059] According to one embodiment, the luminous glazing is single glazing.

[0060] According to a preferred embodiment of the invention, the luminous glazing is a laminated glazing. It further comprises a second substrate (10, 20) and a lamination interlayer (30), in particular made of PVB, arranged between the two substrates to form a laminated glazing, the different faces of the substrates being numbered from 1 to 4 from the outside towards the inside of the passenger compartment or building.

[0061] 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.

[0062] In the case of laminated glazing, all the faces of the substrates are numbered from 1 to 4, but the faces of the lamination interlayers are not numbered. The first coated substrate (10) is located further inside the building or passenger compartment than the second substrate.

[0063] In the case of laminated glazing according to the invention, it comprises a face 1 located outside the building or vehicle that 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. The extractor element (6) is preferably arranged on face 3 or 4, even more preferably on face 3.

[0064] In the case of laminated glazing according to the invention, the light entry face into the substrate (10) is preferably the edge (8) of the substrate coated with the functional coating (5).

[0065] According to another embodiment of the invention, the glazing further comprises a second glass substrate, spaced from the first by a gas layer so as to form double glazing.

[0066] The invention also relates to:

[0067] - luminous glazing according to the invention mounted on a vehicle or on a building, and

[0068] - the use of luminous glazing according to the invention as low-emissivity glazing for buildings or vehicles,

[0069] - a building, a vehicle comprising luminous glazing according to the invention.

[0070] The luminous glazing according to the invention is preferably an automotive glazing such as an automotive roof glazing. The luminous glazing of the invention can be chosen from a side window, a rear window, a roof window or a windshield.

[0071] The light source can be linear such as a strip of diodes.

[0072] The light source can be coupled directly to the substrate material or via a guide, collimating optics.

[0073] The light source is preferably optically coupled to the substrate of the material according to the invention. The optical coupling can be done:

[0074] - by the edge of the substrate of the material of the invention,

[0075] - by a wall delimiting a hole, preferably through, the substrate of the material, or

[0076] - 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.

[0077] 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.

[0078] According to the invention, when a polarizer is used, the power of the light source located opposite said polarizer is reduced, in particular by almost a factor of 2. To compensate for this loss of power, several possibilities are possible. A first possibility consists of doubling the number of light-emitting diodes used.

[0079] White light-emitting diodes are generally obtained by combining three LEDs of primary colors: red + green + blue. According to the invention, it could be envisaged to manufacture "white" LED lamps comprising twice as many LEDs of the color that is absorbed in guided mode and to place polarizers only opposite these LEDs having the color that is absorbed in guided mode. For example, in the case of a functional coating based on conductive oxide absorbing in the red in guided mode, it would be possible to double the number of red diodes and couple each of them to a polarizer.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] Multiple light sources can be used, for example near opposite edges of the substrate.

[0084] The diode(s) can be top-emitting LED or side-emitting LED.

[0085] The diode(s) are preferably on a diode support such as an electronic circuit board, for example a printed circuit board (PCB). The diode support is preferably common to several diodes. The diode support may be opaque, for example by being covered with a layer of varnish or paint, and may even mask the diodes. It may comprise a substrate made of a plastic material.

[0086] When the light entry face into the substrate is the wall of a hole, the diode holder with side-emitting diodes may follow the general shape of the hole and have a main face attached to the bottom of the through-hole, directly or indirectly, for example via a mounting bracket. The diode holder common to several side-emitting diodes may be a disc (or be oblong) or a ring in the circular (or oblong) hole.

[0087] According to one embodiment, the diodes are supplied with electricity by means of a current supply integrated into the laminated glazing. For example, an electric wire can be incorporated into the lamination interlayer.

[0088] The substrates may be mineral glass or transparent polymer material substrates. The substrates are preferably mineral glass.

[0089] The mineral glass substrates that make up the glazing can be soda-lime, aluminosilicate or borosilicate glass.

[0090] The substrates may be made of transparent polymeric material which include poly(methyl methacrylate) (PMMA), polycarbonate (PC), polyurethane or polyurea (PU) or polyethylene terephthalate (PET) substrates.

[0091] Preferably, the first substrate is made of colorless soda-lime mineral glass such as clear or extra-clear glass such as Planiclear® marketed by the Applicant. In the case of single glazing, the first substrate is preferably made of glass and has a thickness preferably between 1 mm and 6 mm. In the case of laminated glazing, the thickness of the first substrate, preferably made of glass, is preferably between 0.6 mm and 3.2 mm, and more preferably between 1.4 mm and 2.2 mm. The second substrate can of course be as transparent and colorless as the first substrate. According to a particular embodiment, a laminated glazing according to the invention consists of two colorless Planiclear® substrates.

[0092] According to another embodiment, the second substrate is made of tinted glass, for example tinted glass having in particular a light absorption greater than 10% such as Vénus®, TSA3+ or TSA4+ also marketed by the Applicant. The second substrate has a thickness preferably between 1.4 mm and 2.1 mm. The luminous glazing according to the invention can be curved.

[0093] Preferably, the lamination interlayers comprise one or more sheets of organic polymers.The organic polymers are chosen 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 (for example poly(vinyl dichloride) (PVDC)), styrenic polymers (for example 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.

[0094] The lamination interlayer has a thickness preferably between 0.2 mm and 1.1 mm. Preferably, the lamination interlayer is transparent.

[0095] The lamination interlayer can be colorless or tinted.

[0096] The invention comprises a light extracting element, preferably a diffusing element in a layer forming a pattern. The diffusing element in a layer may be an enamel in contact with the substrate or formed on the face of a substrate of the luminous glazing by a surface treatment of the sandblasting type, by an acid attack, by deposition of a diffusing layer. The extracting element (6) may be a diffusing element, in a layer, in particular an enamel forming a pattern.

[0097] Examples of diffusing layered elements include acid-etched glass, SAINT-GOBAIN GLASS Satinovo® glass and SAINT-GOBAIN GLASS Smoothlite® diffusing glass.

[0098] In the case of laminated glazing, the layered diffusing element may be formed in the mass of a substrate or interlayer, for example by a laser engraving type treatment. The layered diffusing 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.

[0099] 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.

[0100] In laminated glazing, preferably, the functional coating will be on face 4 and the diffusing element on face 3. According to another embodiment, the functional coating may be on face 3 and the diffusing element on face 4. Finally, if for certain applications it is envisaged to illuminate the exterior, the coating and the diffusing element may then each be on face 1 or 2.

[0101] The layered diffusing element may be a self-supporting diffusing film, preferably bonded to a glazing substrate.

[0102] 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.

[0103] 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.

[0104] 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.

[0105] The layered diffusing element can be opaque or transparent.

[0106] The diffusing layer may comprise a matrix (organic or mineral) and diffusing particles, for example of metal oxide (TiO2 etc.).

[0107] As an example of a transparent mineral diffusing layer, we can cite the transparent enamel as described in application FR3084355

[0108] As an example of an organic transparent diffusing layer, mention may be made of the transparent layer as described in application WO2022023638. 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.

[0109] 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.

[0110] Conventionally, refractive indices are measured at a wavelength of 550 nm.

[0111] According to the invention:

[0112] - light reflection corresponds to the reflection of solar radiation in the visible part of the spectrum,

[0113] - light transmission corresponds to the transmission of solar radiation in the visible part of the spectrum,

[0114] - light absorption corresponds to the absorption of solar radiation in the visible part of the spectrum.

[0115] BRIEF DESCRIPTION OF THE FIGURES

[0116] The invention and its various applications will be better understood by reading the following description and examining the accompanying figure:

[0117] Fig. 1 very schematically represents a luminous laminated glazing according to one embodiment of the invention.

[0118] The glazing comprises two sheets of glass or substrate. The lower substrate 10 is directed towards the interior of the passenger compartment or building and the upper substrate 20 is arranged towards the exterior of the passenger compartment or building. The two substrates 10, 20 are separated by a PVB type lamination interlayer 30. The different faces of the substrates are conventionally numbered from the outside to the inside, 1, 2, 3, 4. In fig. 1, a functional coating 5 is arranged on face 4. A light extraction means 6 is arranged on face 3. This is a layer forming a pattern.

[0119] A light-emitting diode 7 is shown schematically. Its emitting surface faces the edge 8 of the lower substrate 10. A polarizer 9 is arranged between the emitting surface of the diode 7 and the edge 8 of the lower substrate 10. EXAMPLES OF EMBODIMENT

[0120] 1. Functional materials and coatings

[0121] In these examples, the glass substrates are aluminosilicate glass substrates.

[0122] The lamination interlayers are 0.76 mm Poly(vinyl butyral) (“PVB”) interlayers.

[0123] Functional coatings comprise a functional layer located between two dielectric coatings.

[0124] Functional layers (F) are layers of indium tin oxide.

[0125] Dielectric coatings include:

[0126] - layers based on silicon nitride (Si3N4, n550 = 2.0),

[0127] - layers based on silicon oxide (SiO2, n550 = 1.5).

[0128] The deposition conditions of the layers, which were deposited by sputtering (so-called “magnetron cathode sputtering”), are summarized in Table 1.

[0129] [Table 1]

[0130] Rev. 1: This functional coating comprises the following sequence of layers: Glass

[0131] / / SisN4 30 nm / SiÛ2 17 nm / ITO ni nm / Si3N49 nm / SiÛ2 50 nm

[0132] ITO means: Indium Tin Oxide (lnÛ2:Sn)

[0133] Rev.2: Glass / / Si3N488 nm / SiÛ2 150 nm / ITO 75 nm / Si3N468 nm / SiÛ2 200 nm

[0134] The thicknesses of the layers of this coating were chosen to optimize the optical properties when using an S-type polarizer.

[0135] Rev.3: Glass / / Si3N468 nm / SiO2128 nm / ITO 75 nm / Si3N45 nm

[0136] The thicknesses of the layers of this coating were chosen to optimize the optical properties when using a P-type polarizer. 2. Description of the luminous laminated glazings tested

[0137] The laminated glazing tested includes:

[0138] - a first substrate of ordinary soda-lime glass type of 2mm and

[0139] - a second 2 mm soda-lime glass substrate, the two substrates are separated by a 0.76 mm Polyvinyl Butyral (PVB) lamination interlayer,

[0140] - the functional coating is located on the first substrate and positioned on face 4.

[0141] The first substrate according to the invention is the substrate located furthest inside the passenger compartment or building.

[0142] The first substrate further comprises on face 3 a diffusing element in a layer forming a pattern (6).

[0143] A commercial Spechtech 9 polarizer film was used. This is a linear polarizing laminated film. It belongs to the category of polymer absorbing polarizers.

[0144] It has the following characteristics:

[0145] - a thickness of approximately 0.43 mm,

[0146] - an extinction coefficient of approximately 44:1,

[0147] - a transmission factor of unpolarized light in the wavelength range from 400 to 700 nm of 38%.

[0148] It can be fixed to it by any means, in particular by gluing or by the use of mechanical means.

[0149] The light source 8 is a white LED lamp capable of injecting light into the first substrate via the edge. The light therefore first passes through the polarizer before entering the first substrate. The input face is therefore the edge of the substrate.

[0150] III. Characterization of the absorption effect in guided mode

[0151] Simulations were carried out on laminated luminous glazing coated on face 4 with the functional coatings with low-emissive properties defined above.

[0152] The simulation calculates the change in the light beam, in polarized or unpolarized light, after reflection on the surface of the functional coating. In particular, it calculates the level of reflection and absorption of light, at all wavelengths. Estimating these levels makes it possible to predict the brightness and color of the light extracted by the extractor elements, at any point on the glazing. The parameters Rgm, a*gm and b*gm correspond to the reflections and colors a* and b* in guided mode reflection at the substrate / functional coating interface at an angle of 80° in the glass substrate.

[0153] The light absorption characteristics are obtained by simulation considering the illuminant D65 at 80° perpendicular to the mounted material, and after reflection on the functional coating of the interior of the glass in single or laminated glazing (unless otherwise indicated):

[0154] - AL corresponds to the light absorption in the visible in %,

[0155] - a*abs and b*abs correspond to the absorption colors a* and b* by the coating - L*a*b*observer inside the glass.

[0156] They are summarized in the table below.

[0157] Ex 1 Ex 2 Ex 3

[0158] The Rgm, a*gm and b*gm values ​​in reflection in guided mode at the substrate / functional coating interface were determined. This reflection corresponds to an angle of incidence of 80° in the glass substrate. By definition of the guided mode, whose propagation angle is greater than the value of the critical angle of the system, the light cannot be transmitted through the coating. What is not reflected is therefore absorbed. 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 reflects both lower absorption, particularly in the red, in guided mode and better preservation of the guided mode in terms of its total intensity.

[0159] The parameters a*gm and b*gm indicate the change in the colorimetric parameters of the light upon reflection, for white incident light, of the illuminant type D65.

[0160] A positive a*gm means that the reflection becomes redder than the incident ray.

[0161] A negative a*gm means that the reflection becomes greener than the incident ray.

[0162] A positive b*gm means that the reflection becomes more yellow than the incident ray.

[0163] A negative b*gm means that the reflection becomes bluer than the incident ray.

[0164] 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.

[0165] The higher the absolute value of the a* and b* parameters, the more pronounced the color of the reflections / absorptions will be.

[0166] According to the invention, we are looking for less negative, or even neutral, values ​​of a*gm and b*gm.

[0167] 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.

[0168] It can be seen that for examples 1 and 2, the optical properties and colors are improved with the use of an S-type polarizer, compared to the optical properties and colors obtained without a polarizer. Light reflection is increased and light absorption is decreased. The colors are more neutral (closer to zero).

[0169] For example 3, the optical properties and colors are improved with the use of a P-type polarizer. Depending on the coating used, it is appropriate to choose a type of polarizer and thus improve the intensity and colors of the light pattern.

[0170] The invention also applies to other glazing structures, for example single or double glazing. In the case of single glazing, the critical angle of total internal reflection is no longer 80° but approximately 40°.

[0171] Other coatings could be used, whether they have low emissivity properties or not.

[0172] Other positions can be considered for the cladding and the extractor elements. For example, it is possible to place the cladding on face 3 and the extractor elements on face 4.

[0173] When using RGB LEDs, it could be considered to place the polarizer in front of the red light emission only. This arrangement would have the advantage of further reducing color variation and increasing the power of the light.

Claims

Claims 1. Luminous glazing comprising: - a first substrate coated with a functional coating (5), said substrate comprising two faces and a slice (8), - a light source (7) comprising an emitting surface, optically coupled with the substrate such that the light enters the substrate through an entry face and the substrate forms a light guide, - a light extracting element (6) for extracting the light and forming a light pattern, the glazing being characterized in that it comprises at least one light polarizer (9) located between the emitting surface of the light source (7) and the light entry face in the substrate.

2. Luminous glazing according to the preceding claim, characterized in that the face of entry of the light into the substrate is the edge (8) of the substrate.

3. Luminous glazing according to claim 1, characterized in that the substrate comprises a hole and the face for entry of the light into the substrate is a wall delimiting the hole.

4. Luminous glazing according to any one of the preceding claims, characterized in that the light source (7) is an inorganic light-emitting diode (LED).

5. Luminous glazing according to any one of the preceding claims, characterized in that the substrate is coated with a low-emissivity functional coating (5).

6. Luminous glazing according to the preceding claim, characterized in that the low-emissivity coating (5) comprises a layer of transparent conductive oxide (TCO), in particular ITO.

7. Luminous glazing according to any one of the preceding claims, characterized in that the polarizer is of type S.

8. Luminous glazing according to any one of claims 1 to 6, characterized in that the polarizer is of type P.

9. Glazing according to any one of the preceding claims, characterized in that the polarizer (9) is bonded to the emitting surface of the light source (7).

10. Glazing according to any one of claims 1 to 8, characterized in that the polarizer (9) is bonded to the light entry face in the substrate.

11. Glazing according to any one of claims 1 to 8, characterized in that the emitting surface is spaced from the light entry face in the substrate.

12. Glazing according to any one of the preceding claims, characterized in that the extractor element (6) is a diffusing element, in a layer, in particular an enamel forming a pattern.

13. Glazing according to any one of the preceding claims, characterized in that it is curved.

14. Glazing according to any one of claims 1 to 12, characterized in that it is single glazing.

15. Glazing according to any one of claims 1 to 12, characterized in that it further comprises a second glass substrate, spaced from the first by a gas layer so as to form double glazing.

16. Glazing according to any one of claims 1 to 13, characterized in that it further comprises a second substrate (10, 20) and a lamination interlayer (30), in particular made of PVB, arranged between the two substrates to form a laminated glazing.

17. Glazing according to the preceding claim, characterized in that it is mounted on a passenger compartment or a building, the different faces of the substrates are numbered from 1 to 4 from the outside to the inside of the passenger compartment or the building.

18. Glazing according to the preceding claim, characterized in that the first coated substrate (10) is located further inside the building or passenger compartment than the second substrate.

19. Glazing according to any one of claims 17 or 18, characterized in that the extractor element (6) is arranged on face 3 or 4, preferably 3.

20. Glazing according to any one of claims 17 to 19, characterized in that the face for light to enter the substrate is the edge (8) of the substrate (10) coated with the functional coating (5).

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