Laminated glass for heads-up displays

Abstract

Laminated glazing (10) for head-up display comprising an outer glass sheet (12), an inner glass sheet (14), an adhesive intermediate lamination layer (16) disposed between the outer glass sheet (12) and the inner glass sheet (14), an anti-reflective coating (18), the anti-reflective coating (18) being deposited on an inner face (26) of the inner glass sheet (14) and a functional stack (72) configured to reflect p-polarized light, the functional stack (72) being deposited on an inner face (22) of the outer glass sheet (12) or on an outer face (24) of the inner glass sheet (14), the anti-reflective coating (18) comprising a first anti-reflective module comprising, from the inner face (26) of the inner glass sheet (14), a first nitride-based dielectric layer,an oxide-based layer with a refractive index having a minimum between 800 and 1600 nm and an extinction coefficient increasing monotonically with the wavelength of light, a second dielectric nitride-based layer, and a low-refractive-index layer, the refractive index of the low-refractive-index layer being less than 1.9 at 550 nm. Figure for the abstract: Fig. 1,

Description

Title of the invention: LAMINATED GLAZING FOR HEAD-UP DISPLAYS technical field

[0001] The present description relates to laminated glass for head-up display. Previous technique

[0002] Modern vehicles are now equipped with display systems or devices called "head-up display", also known as HUD in accordance with the English acronym for Head-Up Display.

[0003] These systems or devices include a projector, generally located near the vehicle's dashboard, configured to project an image onto an area of ​​the vehicle's windshield. The projected image appears to the driver as a virtual image behind the windshield, allowing information such as vehicle speed, navigation instructions, or warnings to be displayed directly in their field of vision. The driver no longer needs to take their eyes off the road to consult this information and remains alert to events occurring outside the vehicle. HUD systems or devices thus contribute to improved road safety.

[0004] Most HUD devices rely on the emission of electromagnetic radiation polarized with an s-type polarization and an angle of incidence of approximately 65° to the normal to the windshield. This angle is close to the Brewster angle for a glass-air interface, which is approximately 56.5° for soda-lime glass. The projected image is then reflected by the two main external surfaces of the windshield. In addition to the main image, a secondary image also appears, more or less offset and partially overlapping the main image. This secondary image is called a "ghost image," "double image," or simply "ghost image."

[0005] To mitigate this unwanted ghosting phenomenon, it is common practice to arrange the main surfaces of the windshield at different angles by inserting a laminated interlayer of varying thickness so as to cause the ghost image and the main image to overlap. This type of glazing is generally known as "wedge glazing" or "wedge windshield".

[0006] By way of example, EP 0 420 228 describes a windshield comprising a laminated interlayer whose thickness gradually decreases between a first and a second side of the windshield so that the two sheets of glass in adhesive contact with said interlayer have two different angles of inclination with respect to the projector.

[0007] This type of glazing is however expensive to manufacture, limited to certain viewing angles of the projected image and does not prevent the formation of a ghost image when the glazing includes a functional coating.

[0008] It is common alternative practice to use HUD devices whose implementation is based on the emission of electromagnetic radiation polarized according to a p-type polarization and on a windshield comprising a functional coating adapted to the formation of a new reflective interface within said windshield for this type of radiation.

[0009] When p-polarized electromagnetic radiation is emitted towards the windshield at an angle of incidence close to Brewster's angle, it is weakly reflected by the glass-air interfaces. Reflection occurs only at the reflective interface formed by the functional coating. Different types of functional coatings can be used.

[0010] WO 2005 / 017600 describes a polarizing optical film comprising a plurality of individual layers having different optical refractive indices. The film is intended to be laminated into laminated glass to form a head-up display windshield comprising an area that predominantly reflects visible light polarized according to a p-polarization. The film can also reflect infrared radiation in order to reduce greenhouse effects in a vehicle.

[0011] DE 102014220189 describes a laminated glazing comprising a metallic functional layer based on silver or aluminium and with a thickness between 5 nm and 9 nm. The metallic functional layer allows the reflection of visible light polarized according to a p polarization.

[0012] WO 2016 / 058474, WO 2021 / 104800, WO 2019 / 046157, WO 2020 / 094422 describe laminated glazing for head-up displays with a functional coating comprising one or more metallic functional layers, in particular silver-based, allowing the reflection of visible light polarized according to a p polarization. The functional coating may also include dielectric layers which, optionally combined with the metallic functional layers, confer other properties such as solar control properties and / or color neutralization of the coating in transmission and / or reflection. Description of the invention

[0013] The present exposition aims to remedy at least some of these drawbacks.

[0014] To this end, the present description relates to laminated glass for head-up displays comprising: - an outer sheet of glass; - an internal sheet of glass; - an intermediate adhesive layer of lamination placed between the outer glass sheet and the inner glass sheet; - an anti-reflective coating, the anti-reflective coating being deposited on an inner face of the inner glass sheet, the inner face being opposite the adhesive intermediate layer of lamination; and - a functional stack configured to reflect p-polarized light, the functional stack being deposited on an inner face of the outer glass sheet, the inner face being adjacent to the adhesive intermediate layer of lamination, or on an outer face of the inner glass sheet, the outer face being adjacent to the adhesive intermediate layer of lamination; the anti-reflective coating comprising a first anti-reflective module comprising, from the inner face of the inner glass sheet, a first nitride-based dielectric layer, an oxide-based layer having a refractive index having a minimum between 800 and 1600 nm and an extinction coefficient increasing monotonically with the wavelength of the light, a second nitride-based dielectric layer and a low refractive index layer, the refractive index of the low refractive index layer being less than 1.9 at 550 nm.

[0015] The anti-reflective coating makes it possible to obtain a reflected image of the polarized light p by the functional stacking of satisfactory quality and superior to known head-up displays.

[0016] Indeed, since the coating is an anti-reflective coating, most of an incident light ray will be diffracted.

[0017] Since the inner surface of the internal glass sheet is equipped with the anti-reflective coating, the light ray diffracted at the interface between the anti-reflective coating and the internal glass sheet is of greater intensity compared to the intensity of the light ray diffracted in the absence of the anti-reflective coating. The formation of a so-called "ghost" image due to the reflection by the anti-reflective coating of the diffracted ray at the interface between the anti-reflective coating and the internal glass sheet is reduced. The light ray diffracted at the interface between the anti-reflective coating and the internal glass sheet is then reflected by the functional stack to form the image of the head-up display, a portion of the light ray diffracted at the interface between the anti-reflective coating and the internal glass sheet being diffracted by the functional stack.The light ray arriving at the interface between the outer glass sheet and the atmosphere, the portion of this light ray reflected at the interface between the outer glass sheet and the atmosphere being of even lower intensity. The formation of a so-called "ghost" image due to the reflection at the interface between the glass sheet. external glass and the atmosphere of the diffracted ray at the interface between the anti-reflective coating and the internal glass sheet is reduced.

[0018] Moreover, the refractive index of the oxide-based layer passes through a minimum and the extinction coefficient increases with the wavelength of the light.

[0019] By modifying the deposition conditions of the oxide-based layer, it is possible to modify the characteristics of the anti-reflective coating.

[0020] It is understood that the refractive index of the oxide-based layer passing through a minimum, the value of the refractive index increases with the wavelength of the light after passing through the minimum value.

[0021] The presence of the first nitride-based dielectric layer and the second nitride-based dielectric layer sandwiching the oxide-based layer makes it possible to limit, or even avoid, the oxidation of the oxide-based layer and thus to preserve the properties of the oxide-based layer by avoiding the oxidation of the oxide-based layer.

[0022] By “light transmission”, TL, means light transmission, denoted TL, as defined and measured and / or calculated in ISO 13837:2021.

[0023] By “solar factor”, TTS, it is understood that the solar factor is as defined according to ISO 13837:2021-. It is equal to the sum of the direct solar transmittance, TE, and the secondary heat flux, qi.

[0024] By “direct solar transmittance”, TE means direct solar transmittance as defined and calculated according to ISO 13837:2021.

[0025] By “solar selectivity”, SE, it is understood that the ratio between the light transmission, TL, and the direct solar transmittance, TE.

[0026] By "selectivity", s, it is understood that the ratio of light transmission, TL, to the solar factor TTS is the ratio of light transmission, TL, to solar factor TTS.

[0027] By “light reflection” R, light reflection is understood as defined and measured and / or calculated in ISO 13837:2021.

[0028] In some embodiments, the refractive index of the oxide-based layer has a difference between the minimum and a value at 400 nm greater than or equal to 0.8, in particular greater than or equal to 1.0.

[0029] In some embodiments, the extinction coefficient is less than 0.2, or even 0.1 at 500 nm and less than 2.0, or even less than 1.5 at 1200 nm.

[0030] In some embodiments, the extinction coefficient is greater than or equal to 0.5 at 1600 nm.

[0031] In some embodiments, the extinction coefficient has a difference between 400 nm and 1200 nm greater than or equal to 0.5.

[0032] Selectivity can thus be favorably increased.

[0033] In some embodiments, the anti-reflective coating comprises at least two anti-reflective modules.

[0034] In some embodiments, the oxide is a substoichiometric tungsten oxide, preferably of chemical formula WOS, x being between 2.55 and 2.98.

[0035] In some embodiments, a physical thickness of the substoichiometric tungsten oxide-based layer is greater than or equal to 5 nm and less than or equal to 40 nm, preferably greater than or equal to 5 nm and less than or equal to 20 nm.

[0036] In some embodiments, the oxide is a doped tungsten oxide of formula MyWi yO3, M representing at least one dopant element selected from the chemical elements of group 1 according to the IUP AC nomenclature and being between 0.01 and 0.4, preferably between 0.01 and 0.2, even more preferably between 0.01 and 0.1.

[0037] In some embodiments, the doped tungsten oxide has the formula CsyW i yO3, y being between 0.01 and 0.4, preferably between 0.01 and 0.2, even more preferably between 0.01 and 0.1.

[0038] In some embodiments, a physical thickness of the layer based on doped tungsten oxide is greater than or equal to 5 nm and less than or equal to 40 nm, preferably greater than or equal to 5 nm and less than or equal to 20 nm.

[0039] In some embodiments, the first and / or second nitride-based dielectric layer is a silicon nitride-based dielectric layer and has a physical thickness greater than or equal to 5 nm.

[0040] In some embodiments, the low refractive index layer is silica-based.

[0041] In some embodiments, the low refractive index layer is silica-based comprising alumina.

[0042] In some embodiments, the low refractive index layer has a physical thickness greater than or equal to 5 nm and less than or equal to 110 nm, preferably greater than or equal to 5 nm and less than or equal to 90 nm.

[0043] In some embodiments, the functional stack is a solar control functional stack.

[0044] In some embodiments, the functional stack comprises at least one metallic functional layer.

[0045] In some embodiments, the metallic functional layer is silver-based, preferably silver.

[0046] In certain embodiments, in which the metallic functional layer has a physical thickness less than or equal to 20 nm.

[0047] In some embodiments, the functional stack comprises two metallic functional layers.

[0048] In some embodiments, a physical thickness of a first metallic functional layer is strictly less than a physical thickness of a second metallic functional layer.

[0049] The first metallic functional layer is arranged between the inner face of the inner glass sheet and the second metallic functional layer.

[0050] In some embodiments, the functional stack comprises dielectric layers surrounding each metallic functional layer.

[0051] It is understood that each metallic functional layer is sandwiched between dielectric layers.

[0052] By way of non-limiting examples, the dielectric layer may include a dielectric layer in particular with a barrier function, a dielectric layer in particular with a stabilizing function, a dielectric layer in particular with a smoothing function and / or a dielectric layer in particular with a blocking function.

[0053] The external and / or internal glass sheet is preferably colorless, non-opaque and non-translucent in order to minimize the absorption of light and thus maintain maximum light transmission in the visible electromagnetic spectrum.

[0054] Laminated glazing has a light transmission greater than or equal to 71% and is neutral in color in reflection and transmission.

[0055] In some embodiments, the internal and / or external glass sheet is a mineral glass tinted in mass.

[0056] Colouring can generally be achieved by adding colouring oxides to the chemical composition of the glass. Examples of colouring oxides include iron(II) oxide, copper oxide, chromium oxide, nickel oxide, gold oxide, manganese oxide, cobalt oxide, uranium oxide, neodymium oxide, and erbium oxide. Mixtures of oxides such as copper and tin oxide, or ionic complexes such as iron-sulfur or cadmium-sulfur complexes, can also be used.

[0057] In some embodiments, the anti-reflective coating includes a protective coating for the anti-reflective coating disposed opposite the inner glass sheet, in particular the inner face of the inner glass sheet.

[0058] The protective coating may comprise several protective layers.

[0059] In some embodiments, the selectivity of the laminated glazing is greater than or equal to 1.25, in particular greater than or equal to 1.35.

[0060] In some embodiments, the ratio of the light reflection of the functional stack to the light reflection of an external face of the external glass sheet is greater than or equal to 15, or even greater than or equal to 20.

[0061] The higher the ratio, the better the quality of the head-up display, i.e. the "ghost" image will be of very low intensity compared to the image reflected by the functional stack.

[0062] In some embodiments, the ratio of light reflection of the functional stack to the light reflection of the anti-reflective coating is greater than or equal to 20, or even greater than or equal to 25.

[0063] The higher the ratio, the better the quality of the head-up display will be, i.e. the "ghost" image will be of very low intensity compared to the image reflected by the functional stack.

[0064] In some embodiments, the outer glass sheet and / or the inner glass sheet has a thickness of between 0.4 and 1.1 mm, in particular between 0.4 and 0.7 mm.

[0065] In some embodiments, the intermediate adhesive layer of lamination comprises one or more layers of thermoplastic material.

[0066] Examples of thermoplastic material are polyurethane, polycarbonate, polyvinyl butyral (PVB), polymethyl methacrylate (PMMA), ethylene vinyl acetate (EA) or an ionomer resin.

[0067] In some embodiments, the intermediate adhesive layer of lamination has acoustic properties.

[0068] In some embodiments, the intermediate adhesive layer of lamination is UV-resistant. Brief description of the drawings

[0069] Other features and advantages of the subject matter of this presentation will become apparent from the following description of embodiments, given by way of non-limiting examples, with reference to the attached figures.

[0070] [Fig.1] Fig.1 is a schematic view of laminated glazing according to one embodiment.

[0071] [Fig.2] The [Fig.2] is a schematic cross-sectional view of an internal glass sheet provided with an anti-reflective coating according to one embodiment.

[0072] [Fig.3] The [Fig.3] is a schematic cross-sectional view of an internal or external glass sheet provided with a functional stack according to an embodiment.

[0073] [Fig.4] The [Fig.4] is a schematic cross-sectional view of an internal or external glass sheet provided with a functional stack according to another embodiment.

[0074] [Fig. 5] Fig. 5 is a graph representing the refractive index (unitless) in function of the wavelength of the light (in nm).

[0075] [Fig.6] Fig.6 is a graph representing the extinction coefficient (unitless) depending on the wavelength of the light (in nm).

[0076] Throughout all the figures, the common elements are identified by identical numerical references. Detailed description

[0077] In what follows, the elements common to the different embodiments are identified by the same numerical references. aôQ

[0078] Fig. 1 is a schematic cross-sectional view of laminated glazing according to one embodiment.

[0079] In the embodiment of [Fig. 1], the laminated glass 10 is laminated glass for head-up displays. The laminated glass 10 comprises an outer glass sheet 12 and an inner glass sheet 14. The laminated glass 10 includes an adhesive intermediate layer of lamination 16 disposed between the outer glass sheet 12 and the inner glass sheet 14. The outer glass sheet 12 has an outer face 20 and an inner face 22, and the inner glass sheet 14 has an outer face 24 and an inner face 26.

[0080] The outer face 20 of the outer glass sheet 12 is opposite the intermediate adhesive layer of lamination 16, that is to say that the inner face 22 of the outer glass sheet 12 is closer to the intermediate layer of lamination 16 than the outer face 20 of the outer glass sheet 12.

[0081] The inner face 26 of the inner glass sheet 14 is opposite the adhesive intermediate layer of lamination 16, i.e. the outer face 24 of the inner glass sheet 14 is closer to the intermediate layer of lamination 16 than the inner face 26 of the inner glass sheet 14.

[0082] In this description, the terms "internal" and "external" are used in relation to laminated glazing when the latter is installed on a motor vehicle, for example. The term "external" refers to an element closer to the exterior of the vehicle and the term "internal" to an element closer to the interior of the vehicle.

[0083] In the embodiment of [Fig. 1], the inner face 26 of the inner glass sheet 14 is provided with an anti-reflective coating 18 and the inner face 22 of the outer glass sheet is provided with a functional stack 72. The functional stack 72 could alternatively be deposited on the outer face 24 of the inner glass sheet 14, the inner face 26 of the inner glass sheet 14 being provided with the anti-reflective coating 18 and the outer face 24 of the inner glass sheet 14 being equipped with the functional stack 72. The functional stack 72 is configured to reflect p-polarized light.

[0084] As illustrated in [Fig. 1], an incident light ray 28 of p-polarized light is mainly diffracted by the anti-reflective coating 18 forming a diffracted light ray 56. Although the angle of the incident light ray 28 is oriented at approximately 65°, that is close to the Brewster angle, with respect to the bisector 34 of the angle formed between the incident light ray 28 and the secondary light ray 32B, that is to say the perpendicular to the inner face 26 of the inner glass sheet 14, the anti-reflective coating 18 reflects a very small part of the incident light ray 28 to form a secondary light ray 32B.

[0085] In the embodiment of [Fig. 1], the outer glass sheet 12, the inner glass sheet 14, and the intermediate adhesive lamination layer 16 have similar or even equal refractive indices. Therefore, the diffracted light ray 56 is only slightly deviated when passing through the interfaces between the inner glass sheet 14, the intermediate adhesive lamination layer 16, the functional stack 72, and the outer glass sheet 12.

[0086] When the diffracted light ray 56 reaches the interface between the adhesive laminate intermediate layer 16 and the functional stack 72, the diffracted light ray 56 is reflected by the functional stack 72 towards the inner glass sheet 14 (reflected light ray 58B). The reflected light ray 58B by the functional stack 72 is only slightly modified when passing through the interfaces between the functional stack 72, the adhesive laminate intermediate layer 16, and the inner glass sheet 14. At the interface between the anti-reflective coating 18 and the internal atmosphere, the reflected light ray 58B is diffracted and forms a reflected light ray 30, which forms the main image of the head-up display.

[0087] The intensity of the secondary light ray 32B creates for an observer located on the side of the inner face 26 of the inner glass sheet 14, i.e. in the vehicle, a low intensity secondary image also called a ghost image or "ghost" which is superimposed on the image created by the light ray reflected 30 by the functional stack 72. The "ghost" images potentially created at the interfaces with the intermediate adhesive layer of lamination 16 are negligible compared to the light ray reflected 30 by the functional stack 72 and the secondary light ray 32B.

[0088] When the diffracted light ray 56 reaches the interface between the outer glass sheet 12 and the external atmosphere, the diffracted light ray 56 is reflected by the outer face 20 of the outer glass sheet 12 towards the inner glass sheet 14 (reflected light ray 58A). The reflected light ray 58A from the outer face 20 of the outer glass sheet 12 is only slightly modified during its passage through the interfaces between the outer glass sheet 12, the functional stack 72, the intermediate adhesive lamination layer 16, and the inner glass sheet 14. At the interface between the anti-reflective coating 18 and the interior atmosphere, the reflected light ray 58A is diffracted and forms a secondary light ray 32A. The intensity of the secondary light ray 32A creates, for an observer located on the inner face 26 of the inner glass sheet 14, i.e., inside the vehicle, a low-intensity secondary image, also called a ghost image, which is superimposed on the image created by the light ray reflected 30 by the functional stack 72. The potential ghost images created at the interfaces with the intermediate adhesive lamination layer 16 are negligible compared to the light ray reflected 30 by the functional stack 72 and the secondary light ray 32A.

[0089] Figure 2 is a schematic cross-sectional view of an internal glass sheet 14 equipped of the anti-reflective coating 18 according to an embodiment.

[0090] In the embodiment of [Fig.2], the anti-reflective coating 18 comprises two anti-reflective modules, a first anti-reflective module 36 and a second anti-reflective module 38. Each anti-reflective module 36, 38 comprises, from the inner face 26 of the inner glass sheet 14, a first nitride-based dielectric layer 42A, 42B, an oxide-based layer 44A, 44B, having a refractive index having a minimum between 800 and 1600 nm and an extinction coefficient increasing with the wavelength of the light, a second nitride-based dielectric layer 46A, 46B, and a low refractive index layer 48A, 48B, the refractive index of the low refractive index layer being less than 1.9 at 550 nm.

[0091] The anti-reflective coating 18 may include an anti-reflective module 36.

[0092] The [Fig.3] is a schematic cross-sectional view of an internal 14 or external 12 glass sheet equipped with the functional stacking 72 according to one embodiment.

[0093] In the embodiment of [Fig.3], the functional stack 72 comprises a metallic functional layer 80A.

[0094] In the embodiment of [Fig.3], the metallic functional layer 80A is contained between dielectric layers.

[0095] In the embodiment of [Fig. 3], starting from the outer face 24 of the inner glass sheet 14 or the inner face 22 of the outer glass sheet 12, the functional stack 72 comprises two dielectric layers 76AA, 78AA, the metallic functional layer 80A and four dielectric layers 82A, 78AB, 76AB, 74. (To be corrected)

[0096] Figure 4 is a schematic cross-sectional view of an internal glass sheet 14 or external 12 equipped with the functional stacking 72 according to another embodiment.

[0097] In the embodiment of [Fig. 4], the functional stack 72 comprises at least one metallic functional layer 80A, 80B. The functional stack 72 may comprise one metallic functional layer 80A or two metallic functional layers 80A, 80B.

[0098] In the embodiment of [Fig. 4], each metallic functional layer 80A, 80B is contained between dielectric layers. The dielectric layers separate the metallic functional layers from each other.

[0099] Arbitrarily, the functional stack 72 of [Fig.4] is decomposed into two functional modules 84, 86, a dielectric layer 74A, 74B, 74C, being disposed on either side of each module 84, 86.

[0100] In the embodiment of [Fig.4], starting from the outer face 24 of the inner glass sheet 14 or from the inner face 22 of the outer glass sheet 12, the functional stack 72 comprises a first dielectric layer 74A, a first functional module 84, a second dielectric layer 74B, a second functional module 86 and a third dielectric layer 74C.

[0101] In the embodiment of [Fig.4], starting from the outer face 24 of the inner glass sheet 14 or from the inner face 22 of the outer glass sheet 12, the first functional module 84 comprises two dielectric layers 76A, 78AA, a metallic functional layer 80A and two dielectric layers 82A, 78AB.

[0102] In the embodiment of [Fig.4], starting from the outer face 24 of the inner glass sheet 14 or from the inner face 22 of the outer glass sheet 12, the second functional module 86 comprises two dielectric layers 76B, 78BA, a metallic functional layer 80B and two dielectric layers 82B, 78BB.

[0103] By way of example, the deposition of an anti-reflective coating and / or a functional stack comprising thin films on a glass substrate is carried out by successive deposits of each thin film by passing the glass substrate through a succession of deposition cells adapted to deposit a given thin film.

[0104] Deposition cells can use deposition methods such as magnetic field assisted sputtering (also called magnetron sputtering), ion beam assisted deposition (IBAD), evaporation, chemical vapor deposition (CVD), plasma-assisted chemical vapor deposition (PECVD), low-pressure chemical vapor deposition (LPCVD), etc.

[0105] The magnetic field assisted spray deposition process is particularly used.

[0106] The tungsten oxide target may in particular contain one or more dopant elements in the proportions as described for the doped tungsten oxide layer.

[0107] The tungsten oxide-based layer can be deposited by sputtering using the aforementioned target under a deposition atmosphere composed of 20 to 100% argon and 0 to 80% dioxygen, preferably 30 to 90% argon and 10 to 70% dioxygen.

[0108] The tungsten oxide-based layer can be deposited under a pressure of between 1 and 20 mTorr, preferably from 3 to 15 mTorr.

[0109] Preferably, the deposition can be carried out cold, i.e. at a temperature below 100°C, in particular between 20°C and 60°C, for the substrate.

[0110] The deposition can also be carried out hot, in particular at a temperature between 100°C and 400°C.

[0111] The inner glass sheet 14, equipped with the reflective coating 18, can undergo annealing heat treatment. The annealing temperature can be between 450°C and 800°C, in particular between 550°C and 750°C, or even between 600°C and 700°C. The annealing time can be between 5 and 30 minutes, in particular between 5 and 20 minutes, or even between 5 and 10 minutes. The same applies when the inner glass sheet 14 is equipped on its inner face 26 with the reflective coating 18 and on its outer face 24 with the functional stack 72.

[0112] The outer glass sheet 12 equipped with the functional stack 72 can undergo annealing heat treatment. The annealing temperature can be between 450°C and 800°C, in particular between 550°C and 750°C, or even between 600°C and 700°C. The annealing time can be between 5 min and 30 min, in particular between 5 min and 20 min, or even between 5 min and 10 min.

[0113] In the examples below, the thin films are deposited by magnetic field assisted sputtering.

[0114] For Example 1 (Exl), Example 2 (Ex2), Example 3 (Ex3), Comparative Example 1 (ExC 1), and Comparative Example 2 (ExC 2), the outer glass sheet 12 is a soda-lime-silica glass 1.6 mm thick, the adhesive laminate intermediate layer 16 is a PVB 0.76 mm thick, and the inner glass sheet 14 is a soda-lime-silica glass 2.1 mm thick. The inner face 26 of the inner glass sheet 14 is provided with the reflective coating 18, and the inner face 22 of the outer glass sheet 12 is provided with the functional stack 72.

[0115] Example 1

[0116] Anti-reflective coating 18

[0117] The anti-reflective coating 18 of Example 1 is according to the embodiment of [Fig.2] and includes an anti-reflective module 36.

[0118] The first 42A nitride-based dielectric layer and the second 46A nitride-based dielectric layer are made of aluminum-doped silicon nitride. The target used is a Si:Al target comprising 92% by weight of silicon and 8% by weight of aluminum nitride. of aluminium. The layer is deposited at a pressure between 3.2.10 3 and 6.103 mbar in an atmosphere of argon and nitrogen with an Ar / (Ar+N2) ratio of 55 (in flight%).

[0119] The 44A oxide-based layer is made of substoichiometric tungsten oxide WOX. The target used is a tungsten target. The layer is deposited at a pressure of 12 mTorr in an atmosphere containing 60% by volume of dioxygen.

[0120] The low refractive index 48A layer is made of silica comprising alumina. The target used is a Si:Al target comprising 92% by weight of silicon and 8% by weight of aluminum. The layer is deposited at a pressure of 4.103 mbar in an atmosphere of argon and dioxygen with an Ar / (Ar+O2) ratio of 36 (by volume%).

[0121] After deposition of the anti-reflective module 36, the inner glass sheet 14 with the reflective coating 18 is annealed at 650°C for 10 min. The sub-stoichiometric tungsten oxide WOX has an x ​​value of approximately 2.9.

[0122] Functional stacking 72

[0123] The functional stack 72 of Example 1 is according to the embodiment of [Fig.4] and includes a metallic functional layer 80A.

[0124] The dielectric layers 76AA, 76AB, are made of aluminum-doped SiZrN. The target used is a Si:Zr:Al target comprising 78 at% Si, 17 at% Zr and 5 at% Al. The layer is deposited at a pressure of 2.103 mbar in an argon-nitrogen atmosphere with an Ar / (Ar+N2) ratio of 45 (in flight%).

[0125] The dielectric layers 78AA, 78AB, are made of ZnO comprising alumina. The target used is a Zn:Al target comprising 98% by weight zirconium and 2% by weight aluminum. The layer is deposited at a pressure of 1.8 x 10³ mbar in an argon and oxygen atmosphere with an Ar / (Ar+O₂) ratio of 63 (by volume%).

[0126] The metallic functional layer 80A is made of silver. The target used is a silver target. The layer is deposited at a pressure of 8.103 mbar in an argon atmosphere.

[0127] The dielectric layer 82A is made of NiCrOx. The target used is a Ni:Cr target comprising 80 at% nickel and 20 at% chromium in an argon atmosphere. The dielectric layer 82A is oxidized during the deposition of the next layer, in this example the second dielectric layer 7 8AB, and during the heat treatment of the functional stack 72.

[0128] The dielectric layer 74 is made of aluminum-doped silicon nitride. The target used is a Si:Al target comprising 92% by weight of silicon and 8% by weight of aluminum. The layer is deposited at a pressure between 3.2 x 10³ and 6 x 10³ mbar in an argon-nitrogen atmosphere with an Ar / (Ar+N₂) ratio of 55 (by volume%).

[0129] After deposition of the functional stack 72, the outer glass sheet 14 equipped with the functional stack 72 is annealed at 650°C for 10 min.

[0130] Example 2

[0131] Anti-reflective coating 18

[0132] The anti-reflective coating 18 of Example 1 is according to the embodiment of [Fig.2] and includes an anti-reflective module 36.

[0133] The first 42A nitride-based dielectric layer and the second 46A nitride-based dielectric layer are made of aluminum-doped silicon nitride. The target used is a Si:Al target comprising 92% by weight of silicon and 8% by weight of aluminum. The layer is deposited at a pressure between 3.2 x 10³ and 6 x 10³ mbar in an argon-nitrogen atmosphere with an Ar / (Ar+N₂) ratio of 55 (by volume%).

[0134] The 44A oxide-based layer is made of cesium-doped tungsten oxide. The target used is a Cs / W / O ceramic target with a Cs / W ratio between 0.3 and 0.4. The layer is deposited at a pressure of 4 mTorr in an atmosphere containing 20% ​​by volume of dioxygen.

[0135] The low refractive index 48A layer is made of silica comprising alumina. The target used is a Si:Al target comprising 92% by weight of silicon and 8% by weight of aluminum. The layer is deposited at a pressure of 4.103 mbar in an atmosphere of argon and dioxygen with an Ar / (Ar+O2) ratio of 36 (by volume%).

[0136] After deposition of the anti-reflective module 36, the inner glass sheet 14 with the anti-reflective coating 18 is annealed at 650°C for 10 min. Cesium-doped tungsten oxide CsyWi yO3 has a y value of approximately 0.05-0.06.

[0137] Functional stacking 72

[0138] The functional stack-up 72 of Example 2 is similar to the functional stack-up of Example 1.

[0139] After deposition of the functional stack 72, the outer glass sheet 12 equipped with the functional stack 72 is annealed at 650°C for 10 min.

[0140] Example 3

[0141] Anti-reflective coating 18

[0142] The anti-reflective coating 18 of Example 3 is according to the embodiment of [Fig.2] and comprises two anti-reflective modules, the first anti-reflective module 36 and the second anti-reflective module 38.

[0143] The first 42A, 42B nitride-based dielectric layer and the second 46A, 46B nitride-based dielectric layer are made of aluminum-doped silicon nitride. The target used is a Si:Al target comprising 92 wt% silicon and 8 wt% aluminum. The layer is deposited at a pressure between 3.2 x 10³ and 6.103 mbar in an atmosphere of argon and nitrogen with an Ar / (Ar+N2) ratio of 55 (in flight%).

[0144] The oxide-based layer 44A, 44B is made of substoichiometric tungsten oxide WOX. The target used is a tungsten target. The layer is deposited at a pressure of 12 mTorr in an atmosphere containing 60% by volume of dioxygen.

[0145] The low refractive index layer 48A, 48B is made of silica comprising alumina. The target used is a Si:Al target comprising 92% by weight of silicon and 8% by weight of aluminum. The layer is deposited at a pressure of 4.103 mbar in an atmosphere of argon and dioxygen with an Ar / (Ar+O2) ratio of 36 (by volume%).

[0146] After deposition of the first anti-reflective module 36 and the second anti-reflective module 38, the inner glass sheet 14 with the anti-reflective coating 18 is annealed at 650°C for 10 min. The substoichiometric tungsten oxide WOX has an x ​​value of approximately 2.9.

[0147] Functional stacking 72

[0148] The functional stack 72 of example 3 is according to the embodiment of 4 and comprises two metallic functional layers 80A, 80B.

[0149] The dielectric layers 74A, 74B, 74C are made of aluminum-doped silicon nitride. The target used is a Si:Al target comprising 92% by weight of silicon and 8% by weight of aluminum. The layer is deposited at a pressure between 3.2 x 10³ and 6 x 10³ mbar in an argon-nitrogen atmosphere with an Ar / (Ar + N₂) ratio of 55 (by volume%).

[0150] The dielectric layers 76A, 76B, are made of SnZnO. The target used is a Zn:Sn target comprising 64 at% of Zn and 36 at% of Sn. The layer is deposited at a pressure of 2.103 mbar in an atmosphere of argon and oxygen with an Ar / (Ar+O2) ratio of 50 (in flight%).

[0151] The dielectric layers 78AA, 78AB, 78BA, 78BB, are made of ZnO comprising alumina. The target used is a Zn:Al target comprising 98% by weight zirconium and 2% by weight aluminum. The layer is deposited at a pressure of 1.8 x 10³ mbar in an argon and oxygen atmosphere with an Ar / (Ar+O₂) ratio of 63 (by volume%).

[0152] The metallic functional layers 80A, 80B, are made of silver. The target used is a silver target. The layer is deposited at a pressure of 8.103 mbar in an argon atmosphere.

[0153] The dielectric layers 82A, 82B, are made of NiCrOx. The target used is a Ni:Cr target comprising 80 at% nickel and 20 at% chromium in an argon atmosphere. The dielectric layers 82A, 82B, 82C are oxidized during the layer deposition next, in this example the second dielectric layers 78AB, 78BB, 78CB, and during the heat treatment of the functional stack 72.

[0154] After deposition of the functional stack 72, the outer glass sheet 12 equipped with the functional stack 72 is annealed at 650°C for 10 min.

[0155] Comparative example 1

[0156] Comparative example 1 is a laminated glazing comprising a functional stack 72 on the inner face 22 of the outer glass sheet 12 and is devoid of anti-reflective coating 18. The functional stack 72 of comparative example 1 is similar to the functional stack of example 1.

[0157] Comparative example 2

[0158] Comparative example 2 is a laminated glazing comprising a functional stack 72 on the inner face 22 of the outer glass sheet 12 and is devoid of anti-reflective coating 18. The functional stack 72 of comparative example 2 is similar to the functional stack of example 3.

[0159] Table 1 gives the physical thicknesses of each layer, the thicknesses being expressed in nm, for example 1, example 2, example 3 and comparative example 1 and comparative example 2 as well as the values ​​of the selectivity, the ratio R30 / R32b 65° and the ratio R30 / R32a 65°.

[0160] R30 / R32a 65° represents the ratio between the light reflection of the light ray reflected 30 by the functional stack 72 and the secondary light ray 32A measured with an angle of the incident light ray 28 of 65° with respect to the normal, i.e. the bisector 34, to the laminated glazing 10.

[0161] R30 / R32b 65° represents the ratio between the light reflection of the light ray reflected 30 by the functional stack 72 and the secondary light ray 32B measured with an angle of the incident light ray 28 of 65° with respect to the normal, i.e. the bisector 34, to the laminated glazing 10.

[0162] [Tables 1 Ex 1 Ex 2 Ex 3 ExC 1 ExC 2 74A 14 16 76A 9 9 76AA 42 41 44 78AA 5 5 12 5 12 80A 15 14.8 7 15 7 82A 0.5 0.5 1 0.5 1 78AB 5 5 15 5 15 76AB 30 20 20 74 4 17 12 74B 40 38 76B 12 12 78BA 15 15 80B 14 14.2 82B 1 1 78BB 14 14 74C 21 21 42A 5 5 5 44A 5 5 10 46A 5 5 5 48A 64 66 73 42B 5 44B 7 46B 5 48B 5 Selectivity 1.39 1.39 1.62 1.39 1.59 R30 / R32B 65° 42.4 25 29 15.8 10.7 R30 / R32A 65° 25 24.3 31.5 29.5 19

[0163] Figure 5 is a graph representing the refractive index (unitless) as a function of the wavelength of light (in nm). Curve 60 represents the evolution of the refractive index of substoichiometric tungsten oxide as a function of the wavelength of light, curve 62 the evolution of the refractive index of cesium-doped tungsten oxide as a function of the wavelength of light, and curve 64 represents the evolution of the refractive index of stoichiometric tungsten oxide as a function of the wavelength of light. Curve 64 for stoichiometric tungsten oxide is given for illustrative and comparative purposes. We observe that unlike curve 60 of substoichiometric tungsten oxide and curve 62 of cesium-doped tungsten oxide, curve 64 of stoichiometric tungsten oxide does not pass through a minimum and varies little as a function of the wavelength of light.

[0164] Figure 6 is a graph representing the extinction coefficient (unitless) as a function of the wavelength of light (in nm). Curve 66 represents the evolution of the extinction coefficient of sub-stoichiometric tungsten oxide as a function of the wavelength of light, curve 68 the evolution of the extinction coefficient of cesium-doped tungsten oxide as a function of the wavelength of light, and curve 70 represents the evolution of the extinction coefficient of stoichiometric tungsten oxide as a function of the wavelength of light. Curve 70 for stoichiometric tungsten oxide is given for illustrative and comparative purposes. We observe that, unlike the curve 66 of sub-stoichiometric tungsten oxide and the curve 68 of cesium-doped tungsten oxide, the curve 70 of stoichiometric tungsten oxide is not increasing but constant at O.

[0165] Laminated glass 10 is particularly suitable for automotive glazing applications. It can also be adapted for certain building glazing applications, notably as laminated glass.

[0166] Although the present description has been made with reference to a specific embodiment, it is evident that various modifications and changes can be made to these examples without departing from the general scope of the invention as defined by the claims. Furthermore, individual features of the various embodiments mentioned can be combined in additional embodiments. Therefore, the description and drawings should be considered in an illustrative rather than restrictive sense.

Claims

Demands

1. Laminated glazing (10) for head-up display comprising: - an outer glass sheet (12); - an inner glass sheet (14); - an adhesive intermediate lamination layer (16) disposed between the outer glass sheet (12) and the inner glass sheet (14); - an anti-reflective coating (18), the anti-reflective coating (18) being deposited on an inner face (26) of the inner glass sheet (14), the inner face (26) being opposite the adhesive intermediate lamination layer (16); and - a functional stack (72) configured to reflect p-polarized light, the functional stack (72) being deposited on an inner face (22) of the outer glass sheet (12), the inner face (22) being adjacent to the intermediate adhesive lamination layer (16), or on an outer face (24) of the inner glass sheet (14), the outer face (24) being adjacent to the intermediate adhesive lamination layer (16);the anti-reflective coating (18) comprising a first anti-reflective module (36) comprising, from the inner face (26) of the inner glass sheet (14), a first nitride-based dielectric layer (42A), an oxide-based layer (44A) having a refractive index having a minimum between 800 and 1600 nm and an extinction coefficient increasing monotonically with the wavelength of the light, a second nitride-based dielectric layer (46A) and a low refractive index layer (48A), the refractive index of the low refractive index layer (48A) being less than 1.9 at 550 nm.;

2. Laminated glazing (10) according to claim 1, the anti-reflective coating (18) comprises at least two anti-reflective modules (36, 38).

3. Laminated glazing (10) according to claim 1 or 2, wherein the oxide is a substoichiometric tungsten oxide, preferably of chemical formula WOS, x being between 2.55 and 2.

98.

4. Laminated glazing (10) according to claim 3, wherein a physical thickness of the tungsten oxide-based layer under stoichiometric is greater than or equal to 5 nm and less than or equal to 40 nm, preferably greater than or equal to 5 nm and less than or equal to 20 nm.

5. Laminated glazing (10) according to claim 1 or 2, wherein the oxide is a doped tungsten oxide of formula MyWi_ yO3, M representing at least one dopant element selected from the chemical elements of group 1 according to the IUPAC nomenclature and being between 0.01 and 0.4, preferably between 0.01 and 0.2, even more preferably between 0.01 and 0.

1.

6. Laminated glazing (10) according to claim 5, wherein the doped tungsten oxide is of formula CsyWi yO3, y being between 0.01 and 0.4, preferably between 0.01 and 0.2, even more preferably between 0.01 and 0.

1.

7. Laminated glazing (10) according to claim 5 or 6, wherein a physical thickness of the doped tungsten oxide-based layer is greater than or equal to 5 nm and less than or equal to 40 nm, preferably greater than or equal to 5 nm and less than or equal to 20 nm.

8. Laminated glazing (10) according to any one of claims 1 to 7, wherein the first and / or second nitride-based dielectric layer (42A, 42B, 46A, 46B) is a silicon nitride-based dielectric layer and has a physical thickness greater than or equal to 5 nm.

9. Laminated glazing (10) according to any one of claims 1 to 8, wherein the low refractive index layer (48A, 48B) is silica-based.

10. Laminated glazing (10) according to claim 9, wherein the low refractive index layer (48A, 48B) is silica-based comprising alumina.

11. Laminated glazing (10) according to claim 10, wherein the low refractive index layer (48A, 48B) has a physical thickness greater than or equal to 5 nm and less than or equal to 110 nm, preferably greater than or equal to 5 nm and less than or equal to 90 nm.

12. Laminated glazing (10) according to any one of claims 1 to 11, wherein the functional stack (72) comprises at least one metallic functional layer (80A, 80B).

13. Laminated glazing (10) according to claim 12, wherein the metallic functional layer (80A, 80B) has a physical thickness less than or equal to 20 nm.

14. Laminated glazing (10) according to claim 12 or 13, wherein a physical thickness of a first metallic functional layer (80A) is strictly less than a physical thickness of a second metallic functional layer (80B).

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