Laminated glazing comprising silver-based functional coating

Abstract

The invention relates to a material comprising a transparent substrate coated with a functional coating comprising, in order from the substrate: alternating three functional metal layers based on silver, referred to as first, second and third functional layers from the substrate; and four dielectric coatings, referred to as Di1, Di2, Di3 and Di4 starting from the substrate, each having an optical thickness Eo1, Eo2, Eo3 and Eo4 and each comprising at least one dielectric layer, such that each functional metal layer is arranged between two dielectric coatings, characterized in that:-the ratio of the thickness of the second functional metal layer to the thickness of the first functional metal layer Ag2 / Ag1 is greater than or equal to 1.05,-the ratio of the thickness of the second functional metal layer to the thickness of the first functional metal layer Ag2 / Ag1 is greater than or equal to 1.05, and-the ratio of the thickness of the second functional metal layer to the thickness of the second functional metal layer Ag2 / Ag1 is greater than or equal to 1.06. The ratio of the thickness of the first functional metal layer to the thickness of the third functional metal layer, Ag1 / Ag3, is greater than 1.05, and the ratio of the optical thickness, Eo2 / Eo3, is greater than 1.00.

Description

[0001] The present invention relates to materials comprising a transparent substrate coated with a functional coating capable of influencing solar and / or infrared radiation. In the following description, the term "functional" means "capable of controlling solar and / or infrared radiation." The present invention also relates to glazing comprising these materials and the use of such materials for producing thermally insulating and / or solar-protective glazing.

[0002] These glazings can be fitted to vehicles or buildings, in particular to prevent excessive overheating due to the increasing importance of glazed surfaces in vehicle interiors and buildings, so-called "solar control" glazings.

[0003] The present invention particularly relates to functional coatings comprising multiple silver-based functional metal layers. Traditionally, these complex functional coatings are tailored to present a pleasing aesthetic appearance under dry conditions and at reasonable viewing angles. This means that the color should not change when the material or glazing is viewed from the front or slightly from the side.

[0004] In some applications, curved or bent (non-flat) glazing is used, such as in automotive applications like roofs or windshields. In these cases, the functional coating must also adjust to maintain consistency and not significantly change color (i.e., from blue to red) as the viewing angle gradually changes.

[0005] Functional coatings are known which exhibit a bluish or neutral appearance in external reflection within an angle of incidence range of 0° (normal incidence) to 60° relative to the substrate normal.

[0006] However, these functional coatings are optimized under dry conditions, i.e., without considering the presence of water droplets.

[0007] In many applications, at least one side of a glazing unit is exposed to the outside environment. In the event of rain, this side may become wet. However, when water droplets fall onto the outer surface of the material or glazing unit, they can severely degrade the aesthetics. Each drop of water refracts and scatters the incident light over a wide range of angles.

[0008] Figure 1 Schematically shown is the sequential interaction of incident light with laminated glazing in the absence and presence of water drops on the glazing surface. Laminated glazing comprises a material comprising a substrate coated with a functional coating, which is laminated to a second substrate via a lamination interlayer.

[0009] In the absence of water droplets, all incident light rays refracted in the substrate propagate in the substrate at an angle with respect to the normal of less than 41°, which corresponds to the critical angle for air / glass.

[0010] In the presence of water droplets, due to their shape, nearly all incident light is transmitted into the droplets, which have a refractive index of 1.33. The light beam is then refracted twice: once upon entering the droplet (slightly, due to its shape), and again upon exiting. The droplets act like prisms. In this case, depending on the configuration of the droplets, light can be caused to propagate through the substrate at angles of up to 62° relative to the normal, corresponding to the critical angle for water / glass. The presence of water droplets means that light is transmitted into the substrate at angles of 42° to 62° relative to the normal, while in the absence of water droplets, the maximum propagation angle achieved in the substrate would be 42°.

[0011] In the absence of a water droplet, the propagation angle in the material cannot exceed the critical angle between air and glass, which is approximately 42°. In the presence of a water droplet, the water / glass interface presents a much larger critical angle of approximately 62°. Furthermore, the shape of the water droplet causes glancing light rays to propagate within it. Light rays with greater-than-expected angles of incidence (i.e., more glancing within the material) may propagate into the outermost substrate.

[0012] The incident light striking the water droplets is thus refracted and scattered over a wide range of angles in a very small area, and these scattered rays then strike the substrate and then the functional coating at different angles. These rays may then be reflected at various glazing interfaces.

[0013] In the presence of water droplets, light propagates through the substrate at angles not normally observed. However, functional coatings are complex and produce difficult-to-predict interference effects. This significantly impacts aesthetics. Visually, water droplets on glass appear as colored droplets. This appearance is undesirable, especially when these droplets are red in color.

[0014] The object of the present invention is therefore to propose a new material comprising a substrate coated with a functional coating, which improves the aesthetics of glazing on rainy days by reducing or even eliminating this “color droplet” (CD) effect.

[0015] The effects obtained by reflection in the substrate at high angles of incidence describe the color observed at the water droplets due to the diffraction of light by these droplets. To identify functional coatings that might exhibit the appearance of moderately or even slightly colored droplets, the applicant simulated light rays propagating in water at a grazing angle (approximately 75°). These rays would be refracted into the glass at angles above the conventional critical angle (up to 62°). The colors of these reflections at the material's exit were then determined.

[0016] The simulation takes into account the juxtaposition of various reflection phenomena occurring at different interfaces: - water / substrate interface, - substrate / functional coating / laminated interlayer interface, - Laminated interlayer / second substrate interface, - Second substrate / air interface.

[0017] The reflection at the water / substrate interface is color neutral and therefore has little influence on the colored droplet effect.

[0018] The reflection at the interface between the lamination interlayer and the second substrate is very low, if not negligible.

[0019] The reflection at the second substrate / air interface is not necessarily negligible. However, it is generally color neutral and very subdued, especially in the case of automotive roofs incorporating a pigmented substrate.

[0020] On the other hand, the reflection at the interface between substrate / functional coating / laminated interlayer has a very strong influence on the coloration. Due to the functional coating, any color combination is possible.

[0021] In summary, the simulations accounted for all their contributions. However, the presence of the functional coating had the greatest impact on color. To minimize the colored droplet effect, the applicant was interested in developing a functional coating with low chromaticity variation in reflection and a neutral or bluish color in reflection over a wide viewing angle range.

[0022] To identify functional coatings that may exhibit these properties, the applicant is interested in characterizing this "Color Droplet" (hereinafter referred to as CD) effect. To this end, a specific optical model has been developed to account for the CD effect. This model can be used to simulate the values ​​of a* and b* in external reflection, the characteristics of the CD effect, hereinafter referred to as a*cd60 and b*cd60. These colors correspond to the colors produced by light reflected in water at an incident angle of 75° from a material coated with water droplets. The CD effect physically corresponds to the measurement of the color in external reflection after reflection at an angle of 60° from the substrate.

[0023] In order to verify the optical model, experiments were performed using a prism. Figure 2 A diagram shows the setup used in the experiment. A prism with a refractive index of 1.5 was placed on a material comprising a substrate coated with a functional coating. This was illuminated with a white light beam. The applicants detected the reflected color at different observation angles, varying the camera angle from 0° to 60°. The color in the external reflection due to the presence of the prism corresponded to the color obtained in the external reflection due to the presence of the water droplets.

[0024] In order to compare the experimental results with those obtained through simulation, the applicants chose to: - in the case of a prism, positioning the camera at an angle of 60°, and - In the case of the simulation, a reflection angle of 60° in the material was selected.

[0025] A good correlation was obtained between the experimental and simulation results, which indicates that the optical model is satisfactory.

[0026] The applicant assumes that: - For values ​​of a*cd60>12.5 and / or b*cd60>0, there is a CD effect, - For a*cd60°<12.5 and / or b*cd60°<0, the CD effect is moderate, - For a*cd60°<10.0 and b*cd60°<-5, the CD effect is weak.

[0027] Thanks to this optical model, the applicant has identified a class of solutions that meet these criteria. In fact, only specific combinations of thickness characteristics of the functional layer and the dielectric coating enable a moderate or even low CD effect to be achieved.

[0028] The present invention relates to a material or glazing unit which exhibits a uniform and pleasing colour in reflection, preferably a bluish or neutral colour, whether the material is flat or curved and in both dry and wet conditions.

[0029] The present invention relates to a material comprising a transparent substrate coated with a functional coating, the functional coating comprising, starting from the substrate, three alternating silver-based functional metal layers, referred to as the first, second and third functional layers, starting from the substrate; and four dielectric coatings, referred to as Di1, Di2, Di3 and Di4, starting from the substrate, each having an optical thickness Eo1, Eo2, Eo3 and Eo4 and each comprising at least one dielectric layer, such that each functional metal layer is arranged between two dielectric coatings, characterized in that: - the ratio of the thickness of the second functional metal layer to the thickness of the first functional metal layer Ag2 / Ag1 is greater than or equal to 1.05, preferably 1.07 or 1.10, - the ratio of the thickness of the first functional metal layer to the thickness of the third functional metal layer Ag1 / Ag3 is greater than 1.05, preferably 1.07 or 1.10, The ratio of optical thickness Eo2 / Eo3 is greater than 1.00, preferably greater than 1.05, 1.10, 1.15 or 1.20.

[0030] According to the present invention, the second functional layer is thicker than the first and third functional layers, the first dielectric coating is thinner, and the second dielectric coating is thicker.

[0031] The material of the present invention exhibits a pleasing aesthetic appearance even when it contains water droplets or when illuminated at high angles of incidence. The contrast between the color observed on a portion of the material without water droplets and the color observed on a portion of the material with water droplets is less harsh.

[0032] The material maintains its aesthetic appeal in both dry and rainy environments.

[0033] The materials of the present invention advantageously exhibit color at low intensity reflection over a wide range of incident angles. The materials of the present invention advantageously exhibit in external reflection: - appear light blue or neutral in color from all viewing angles, and / or - color stability between 8° and 60°, even in the presence of water drops, and / or - Limited light reflectivity RLext, in particular less than or equal to 20%.

[0034] Color stability is characterized by measuring the color change between two observation angles: Δa*Rext = |a*Rext 60° - a*Rext 0°| and Δb*Rext = |a*Rext60° - a*Rext 0°|. According to the present invention, a color is considered stable if Δa*Rext ≤ 6 and Δb*Rext ≤ 6.

[0035] The functional coating of the invention is particularly suitable for use in laminated glazing to improve thermal comfort and aesthetic appearance when viewed from the outside.

[0036] The present invention therefore relates to a laminated glazing comprising the material according to the invention and at least one second substrate, said material and said second substrate being connected to one another via a first lamination interlayer.

[0037] Typically, the faces of the substrate are numbered from the outside of the passenger compartment or the area in which it is installed toward the inside, thus designating the faces of the glazing starting from the outside. This means that incident sunlight passes through the faces in ascending numerical order. In the case of laminated glazing, all faces of the substrate are numbered, but the faces of the laminated interlayer are not.

[0038] The laminated glazing according to the invention comprises a face 1 on the outside of the building or vehicle in which the laminated glazing is to be provided, faces 2 and 3 in contact with the lamination interlayer, and a face 4 on the inside of the building or vehicle. A silver-based functional coating is then applied to face 2, i.e., the inner face of the outermost substrate.

[0039] The laminated glazing according to the invention may comprise a curved substrate.

[0040] The laminated glazing may further comprise a functional coating comprising a conductive oxide layer on face 4 .

[0041] The present invention also relates to: - a laminated glazing according to the invention mounted on a vehicle or a building, and - use of the laminated glazing according to the invention as glazing for buildings or vehicles, - A building or a vehicle comprising a glazing according to the invention.

[0042] The preferred features appearing in the remainder of the description also apply to the material according to the invention and, where appropriate, to the glazing, method, use, building or vehicle according to the invention.

[0043] All described light characteristics are obtained according to the principles and methods of ISO 9050, EN 410 and ISO 13837 standards relating to the determination of light and sunlight characteristics of glazing units in glass for use in the building industry.

[0044] According to the present invention: - light reflection corresponds to the reflection of solar radiation in the visible part of the spectrum, - light transmission corresponds to the transmission of solar radiation in the visible part of the spectrum, - Light absorption corresponds to the absorption of solar radiation in the visible part of the spectrum.

[0045] Luminous and energy properties are measured using illuminant A at 2°, perpendicular to the material when installed in laminated glazing with a functional coating on face 3 (unless otherwise specified): - TL corresponds to the light transmission in the visible range, expressed in %, - Rext corresponds to the external light reflectance in the visible range, in %, with the observer on the functional coating side, - TE corresponds to the energy transmittance and represents the percentage of solar energy flux that is directly transmitted through the glazed wall, - RE corresponds to the energy reflectance, that is, the percentage of energy from all solar radiation that is reflected by the glass, - TTS corresponds to the total energy transmittance, which is measured according to convention A at a wind speed of 4 m / s.

[0046] Colorimetric properties measured using illuminant D65, observed at 10°, perpendicular to the material when installed in laminated glazing with a functional coating on face 2 (unless otherwise stated): - a*Rext 8° and b* Rext 8° correspond to the colors a* and b* in reflection in the L*a*b* system, measured at an angle of 8° with the observer on the side of the external space, - a*Rext 60° and b*Rext 60° correspond to the colors a* and b* in reflection in the L*a*b* system, measured at an angle of 60° with the observer on the side of the external space, - a*cd60 and b*cd60 correspond to the external reflected colors a* and b* in the L*a*b* system after 60° reflection in the material.

[0047] The material has excellent energy and thermal properties. This translates into: - an energy reflectivity value RE greater than 44%, and / or - an energy transmittance value below 38%, and / or - Total energy transmittance values ​​below 44%, It was measured on a laminated glazing comprising a functional surface coating 2 deposited on a transparent glass substrate and laminated to a second transparent glass substrate via a transparent PVB polymer interlayer.

[0048] These properties are measured on ordinary clear glass. Ordinary clear glass with a thickness of 4 to 6 mm has the following optical properties: - 87 to 91.5% light transmittance, - 7 to 9.5% light reflectivity, - 0.3 to 5% light absorption.

[0049] The transparent PVB laminate interlayer has a light transmittance of over 80%.

[0050] Typically, the refractive index is measured at a wavelength of 550 nm.

[0051] Unless otherwise stated, in the absence of other information, the thicknesses mentioned herein are real or geometric physical thicknesses, denoted as Ep, and are expressed in nanometers (not optical thickness). The optical thickness, Eo, is defined as the physical thickness of the layer in question multiplied by its refractive index at a wavelength of 550 nm: Eo = n*Ep. Since the refractive index is a dimensionless value, the units of optical thickness can be considered to be the same as those chosen for the physical thickness.

[0052] According to the invention, a dielectric coating corresponds to a layer sequence comprising at least one dielectric layer, which is located between the substrate and the first functional layer ( Di1 ), between two functional layers ( Di2 or Di3 ) or above the final functional layer ( Di4 ).

[0053] If the dielectric coating consists of several dielectric layers, the optical thickness of said dielectric coating corresponds to the sum of the optical thicknesses of the different dielectric layers constituting the dielectric coating.

[0054] If the dielectric coating includes an absorbing layer—for which the refractive index at 550 nm includes a non-zero (or non-negligible) imaginary part of the dielectric function—such as a metal layer, the thickness of this layer is not considered when calculating the optical thickness of the dielectric coating.

[0055] The thickness of the barrier layer is not considered when calculating the optical thickness of the dielectric coating.

[0056] In the meaning of the present invention, the terms "first", "second", "third" and "fourth" for functional layers or dielectric coatings are defined starting from the substrate carrying the stack and with reference to layers or coatings having the same function. For example, the functional layer closest to the substrate is the first functional layer, the next functional layer further away from the substrate is the second functional layer, etc.

[0057] The functional coatings are deposited by magnetic field-assisted cathode sputtering (magnetron sputtering). According to this advantageous embodiment, all coatings are deposited by magnetic field-assisted cathode sputtering. Unless otherwise specified, the expressions "above" and "below" do not necessarily mean that two layers and / or coatings are positioned in contact with each other. When a layer is deposited "in contact with" another layer or coating, this means that no layer (or layers) can be interposed between the two layers (or between a layer and a coating).

[0058] In this specification, unless otherwise stated, the expression “based on” used to characterize a material or layer with respect to the substances it contains means that it comprises a component with a mass fraction of at least 50%, in particular at least 70%, preferably at least 90%.

[0059] The functional coating comprises at least three silver-based functional metal layers (F1, F2 and F3), each disposed between two dielectric coatings (Di1, Di2, Di3, Di4).

[0060] The silver-based functional metal layer contains at least 95.0% by weight, preferably at least 96.5% by weight, and better still at least 98.0% by weight of silver relative to the weight of the functional layer. Preferably, the silver-based functional metal layer contains less than 1.0% by weight of metal other than silver relative to the weight of the silver-based functional metal layer.

[0061] The three functional metal layers can meet the following characteristics: - a ratio Ag2 / Ag1 of the thickness of the second functional metal layer to the thickness of the first functional metal layer is comprised between 1.05 and 1.20, between 1.05 and 1.11, or between 1.10 and 1.15, and / or - a ratio Ag1 / Ag3 of the thickness of the first functional metal layer to the thickness of the third functional metal layer comprised between 1.05 and 1.20, or between 1.10 and 1.20, and / or - a ratio Ag2 / Ag3 of the thickness of the second functional metal layer to the thickness of the third functional metal layer comprised between 1.10 and 1.45, or between 1.20 and 1.35, and / or - the first silver-based functional metal layer Ag1 has a thickness of 11 to 14 nm, or 11 to 13.5 nm and / or 11.5 to 13 nm, and / or - the second silver-based functional metal layer Ag2 has a thickness of 12 to 17 nm, or 12.5 to 16 nm, or 13 to 16 nm, or 13 to 14 nm, and / or The third silver-based functional metal layer Ag3 has a thickness of 10 to 15 nm, or 10.5 to 13 nm, preferably 10.5 to 12 nm.

[0062] The stack may further comprise at least one barrier layer located in contact with the functional metal layer.

[0063] The barrier layer generally has the function of protecting the functional layer from possible damage during the deposition of the upper antireflection coating and during possible high-temperature heat treatments of the annealing, bending and / or tempering type.

[0064] The barrier layer is selected from: - metal layers, metal nitride layers and metal oxynitride layers based on metals or metal alloys of one or more elements selected from titanium, zinc, tin, nickel, chromium and niobium, - a metal oxide layer of one or more elements selected from titanium, nickel, chromium and niobium.

[0065] The barrier layers may in particular be layers of Ti, TiN, TiOx, Nb, NbN, Ni, NiN, Cr, CrN, NiCr, NiCrN, SnZnN. When these barrier layers are deposited in the form of metals, nitrides or oxynitrides, they may, depending on their thickness and the nature of the layers surrounding them, undergo partial or complete oxidation, for example during the deposition of subsequent layers or through oxidation in contact with underlying layers.

[0066] According to an advantageous embodiment of the invention, the barrier layer(s) satisfy one or more of the following conditions: - Each silver-based functional metal layer may be located below and / or above, and optionally in contact with, a contact barrier layer selected from a barrier primer and a barrier cap layer, and / or - the barrier layer may be based on at least one element selected from nickel, chromium, niobium, tantalum and titanium, and / or - Each functional metal layer is in contact with a barrier coating, and / or - The thickness of each barrier layer is at least 0.1 nm, preferably 0.2 to 2.0 nm or 0.2 to 0.5 nm.

[0067] According to the present invention, barrier layers are considered not to form part of the dielectric coating. This means that their thickness is not taken into account when calculating the optical or geometric thickness of the dielectric coating in contact with them.

[0068] Within the meaning of the present invention, a "dielectric layer" is understood to mean a material that is "non-metallic" in terms of its properties, i.e., not a metal. In the context of the present invention, this term refers to a material that exhibits an n / k ratio equal to or greater than 5 over the entire wavelength range of the visible region (380 nm to 780 nm).

[0069] The dielectric layers of the coating exhibit the following properties, alone or in combination: - they are deposited by magnetic field assisted cathode sputtering, and / or - they are chosen from oxides or nitrides of one or more elements chosen from titanium, silicon, aluminum, zirconium, tin and zinc, and / or - They are selected from: an oxide layer of one or more elements selected from titanium, silicon, aluminum, zirconium, iron, chromium, cobalt, manganese, tungsten, niobium, bismuth, tantalum, zinc and / or tin, a nitride layer of one or more elements selected from silicon, zirconium and aluminum, an oxynitride layer of one or more elements selected from silicon, zirconium and aluminum, Metal sulfide layer such as zinc sulfide, and / or - They have a thickness greater than 2 nm, preferably between 4 and 100 nm.

[0070] According to an advantageous embodiment of the invention, the dielectric coating of the functional coating satisfies one or more of the following conditions: - The dielectric layer may be based on one or more oxides or nitrides of elements selected from silicon, zirconium, titanium, aluminum, tin, zinc, and / or - at least one dielectric coating comprising at least one dielectric layer having a barrier function, and / or - each dielectric coating comprises at least one dielectric layer having a barrier function, and / or - The dielectric layer with barrier function is based on silicon and / or aluminum compounds selected from oxides such as SiO2 and Al2O3, nitrides Si3N4 and AlN, and oxynitrides SiO x N y and AlO x N y , based on zinc and tin oxides, or based on titanium oxide, - a dielectric layer with a barrier function based on a compound of silicon and / or aluminum, optionally containing at least one other element, such as aluminum, hafnium and zirconium, and / or - at least one dielectric coating comprises at least one dielectric layer having a stabilizing function, and / or - Each dielectric coating comprises at least one dielectric layer having a stabilizing function, and / or - the dielectric layer having a stabilizing function is preferably based on an oxide selected from zinc oxide, tin oxide, zirconium oxide or a mixture of at least two thereof, and / or - a dielectric layer having a stabilizing function, preferably based on a crystalline oxide, in particular on zinc oxide, optionally doped with at least one other element such as aluminum, and / or - Each functional layer is above a dielectric coating, the upper layer of which is a dielectric layer with stabilizing functions, preferably based on zinc oxide, and / or each functional layer is below a dielectric coating, the lower layer of which is a dielectric layer with stabilizing functions, preferably based on zinc oxide.

[0071] Preferably, each dielectric coating consists only of one or more dielectric layers. Preferably, no absorbing layers are present in the dielectric coatings, so as not to reduce light transmission.

[0072] The dielectric layer may have a barrier function. A dielectric layer having a barrier function (hereinafter referred to as a barrier layer) is understood to mean a layer made of a material that forms a barrier to the diffusion of oxygen and water from the ambient atmosphere or from the transparent substrate into the functional layer at high temperatures. Such a dielectric layer is selected from the following layers: - Based on silicon and / or aluminum compounds, selected from oxides such as SiO2 and Al2O3, nitrides such as Si3N4 and AlN, and oxynitrides such as SiO x N y 、AlO x N y , optionally doped with at least one other element, - Based on zinc tin oxide, - Based on titanium oxide.

[0073] Preferably, each coating comprises at least one dielectric layer consisting of: - nitrides or oxynitrides of aluminium and / or silicon, or - mixed oxides of zinc and tin, or - Titanium oxide.

[0074] These dielectric layers have the following thicknesses: - less than or equal to 80 nm, less than or equal to 60 nm, or less than or equal to 25 nm, and / or - Greater than or equal to 5 nm, greater than or equal to 10 nm, or greater than or equal to 15 nm.

[0075] The functional coating of the present invention may include a dielectric layer with a stabilizing function. In the context of the present invention, "stabilizing" means that the properties of the layer are selected to stabilize the interface between the functional layer and the layer. This stabilization leads to an increase in the adhesion of the functional layer to the surrounding layers and actually counteracts the migration of its constituent materials.

[0076] The dielectric layer or layers having a stabilizing function may be in direct contact with the functional layer or separated by a barrier layer.

[0077] Preferably, the final dielectric layer of each dielectric coating layer located below the functional layer is a functionally stabilizing dielectric layer. This is because it is advantageous to have a functionally stabilizing layer (e.g., based on zinc oxide) below the functional layer, as it promotes adhesion and crystallization of the silver-based functional layer and improves its quality and stability at high temperatures.

[0078] It is also advantageous to have a layer with a stabilizing function (for example based on zinc oxide) above the functional layer in order to increase its adhesion and to optimally counteract diffusion of the multilayer on the side opposite the substrate.

[0079] One or more dielectric layers having a stabilizing function may thus be above and / or below at least one functional layer or each functional layer, in direct contact therewith or separated by a barrier layer.

[0080] Advantageously, each dielectric layer having a barrier function is separated from the functional layer by at least one dielectric layer having a stabilizing function.

[0081] The zinc oxide layer may optionally be doped with at least one other element, such as aluminum. Zinc oxide is crystalline. The zinc oxide-based layer preferably contains, in increasing order of preference, at least 90.0 mass%, at least 92 mass%, at least 95 mass%, and at least 98.0 mass% of zinc, relative to the mass of elements other than oxygen in the zinc oxide-based layer.

[0082] Preferably, the dielectric coating of the functional coating comprises a zinc oxide based dielectric layer underlying a silver based metal layer.

[0083] The zinc oxide layer has the following thicknesses in increasing order of preference: - at least 3.0 nm, at least 4.0 nm, at least 5.0 nm, and / or - Up to 25 nm, up to 10 nm, up to 8.0 nm.

[0084] According to an advantageous embodiment of the invention, the dielectric coating satisfies one or more of the following conditions: - the dielectric coating Di1 has an optical thickness Eo1 of 50 to 80 nm, - the dielectric coating Di2 has an optical thickness Eo2 of 160 to 180 nm, - the dielectric coating Di3 has an optical thickness Eo3 of 110 to 150 nm, - the dielectric coating Di4 has an optical thickness Eo4 of 70 to 90 nm, - the ratio of optical thickness Eo1 / Eo2 is less than 0.40, or less than 0.30, - The ratio of optical thickness Eo1 / Eo3 is less than 0.40, - the ratio of optical thickness Eo1 / Eo4 is less than 1.00, - The ratio of optical thickness Eo2 / Eo4 is less than 0.40, - each dielectric coating comprises a silicon-containing layer chosen from silicon nitride-based layers, - the sum of the physical thicknesses of all silicon-containing layers in each dielectric coating is greater than 25% of the total thickness of the dielectric coating, - each dielectric coating layer underlying the functional layer comprises a zinc oxide-based layer situated beneath said functional layer, in contact with said functional layer or separated from said functional layer by a barrier layer, - each dielectric coating located above a functional layer comprises a zinc oxide-based layer located above said functional layer, in contact with said functional layer or separated from said functional layer by a barrier layer, Each dielectric coating layer located below the functional layer comprises a layer based on zinc tin oxide, said layer being located below and in contact with the layer based on zinc oxide.

[0085] The functional coating may optionally include an upper protective layer. The upper protective layer is preferably the last layer of the stack, i.e., the layer furthest from the substrate coated with the stack. These upper protective layers are considered to be included in the final dielectric coating. These layers typically have a thickness of 2 to 10 nm, preferably 2 to 5 nm.

[0086] The protective layer can be chosen from layers of titanium, zirconium, hafnium, zinc and / or tin, this or these metals being in the form of metals, oxides or nitrides. Advantageously, the protective layer is a titanium oxide layer, a tin zinc oxide layer or a layer based on titanium zirconium oxide.

[0087] Another particularly advantageous embodiment relates to a substrate coated with a multilayer, defined starting from a transparent substrate, said multilayer comprising: - a first dielectric coating comprising at least one layer having a barrier function and one dielectric layer having a stabilizing function, - optional barrier layer, - first functional layer, - optional barrier layer, - a second dielectric coating comprising at least a lower dielectric layer having a stabilizing function, a layer having a barrier function and an upper dielectric layer having a stabilizing function, - optional barrier layer, - Second functional layer, - optional barrier layer, - a third dielectric coating comprising at least one lower dielectric layer with a stabilizing function, a layer with a barrier function, and an upper dielectric layer with a stabilizing function, - optional barrier layer, - The third functional layer, - optional barrier layer, - a fourth dielectric coating comprising at least one dielectric layer having a stabilizing function, one layer having a barrier function, - Optional protective layer.

[0088] Another particularly advantageous embodiment comprises a stack which, starting from a substrate, comprises: - a first dielectric coating comprising at least one layer based on sodium nitride and one layer based on zinc oxide, - optional barrier layer, - first functional layer, - optional barrier layer, - a second dielectric coating comprising at least three consecutive layers, a layer based on zinc oxide, a layer based on silicon nitride and a layer based on zinc oxide, - optional barrier layer, - Second functional layer, - optional barrier layer, - a third dielectric coating comprising at least three consecutive layers, a layer based on zinc oxide, a layer based on silicon nitride and a layer based on zinc oxide, - optional barrier layer, - The third functional layer, - optional barrier layer, - a fourth dielectric coating comprising at least one layer based on zinc oxide, a layer based on silicon nitride, and - Optional protective layer.

[0089] In laminated glazing configurations, the following calculated colorimetric properties are used: - materials comprising substrates coated with functional coatings for installation in laminated glazing, - Laminated glazing comprising a material comprising a substrate comprising 2 mm of ordinary soda-lime glass and another 2 mm glass substrate of soda-lime glass, the two substrates being separated by a 0.76 mm polyvinyl butyral (PVB) lamination interlayer, - Silver-based functional coating on surface 2, If present, a functional coating based on a conductive oxide is preferably located on face 4 .

[0090] The substrate can be made of mineral glass or a transparent polymer material. The substrate is preferably made of mineral glass.

[0091] The mineral glass substrate constituting the glazing may be soda-lime glass, aluminosilicate glass or borosilicate glass.

[0092] The substrate can be made of a transparent polymer material including poly(methyl methacrylate) (PMMA), polycarbonate (PC), polyurethane, or polyurea (PU) substrates.

[0093] The substrate is preferably transparent, colorless (it is thus clear or extra-clear glass) or colored, for example blue, gray or bronze.

[0094] The substrate may be ultra-thin glass, for example having a thickness of less than 0.7 mm.

[0095] The substrate may be (heat) strengthened glass.

[0096] Silver-based functional coatings can advantageously be deposited on transparent glass substrates in order to maximize the reflection of infrared radiation and thereby achieve a low total energy transmission.

[0097] Silver-based functional coatings can be deposited on pigmented substrates to neutralize the exterior reflective appearance. However, in this case, a compromise must be found between color neutralization and energy performance.

[0098] Preferably, the laminate interlayer comprises one or more sheets of an organic polymer. The organic polymer is selected from polyvinyl butyral (PVB), polyurethane (PU), polyurea, ethylene vinyl acetate (EVA), polyolefins (including polyethylene (PE), polypropylene (PP), or polyisobutylene (P-IB)), polyvinyl chloride and its derivatives (such as polyvinyl dichloride (PVDC)), styrene polymers (such as polystyrene (PS), acrylonitrile butadiene styrene (ABS), and 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), polyamide (PA), fluoropolymers such as polychlorotrifluoroethylene (PCTFE), polycarbonate (PC), aromatic polysulfones including polysulfone (PSU), polyphenylene ether (PPE), and epoxy resins (EP), alone or in blends and / or copolymers of several of these. The laminate interlayer may be pigmented.

[0099] The interlayer is typically 0.20 to 3.00 mm thick. The interlayer may consist of one or more polymer sheets. The thickness ranges given are for the total thickness of the interlayer.

[0100] The material, that is, the substrate coated with the functional coating, can undergo high-temperature heat treatment, such as annealing (e.g., by flash annealing, such as laser or flame annealing), tempering, and / or bending. The heat treatment temperature is greater than 400°C, preferably greater than 450°C, and more preferably greater than 500°C. The functionally coated substrate can thus be bent and / or tempered.

[0101] The material of the invention is particularly suitable for laminated automotive glazing, in particular curved glazing such as roof glazing or windshield glazing. The laminated glazing according to the invention is therefore preferably an automotive glazing, such as an automotive roof glazing or windshield glazing.

[0102] The laminated glazing may also have a light transmittance of more than 60%, more than 70% or more than 80%. The laminated glazing according to the invention, when used in particular as windshield or side glazing, preferably has a TL light transmittance of at least 70% and even at least 75% or even at least 80%.

[0103] The laminated glazing may have a light transmittance of less than 50%, less than 30%, less than 20% or less than 10%.The laminated glazing according to the invention, in particular when used as a skylight, preferably has a light transmittance TL of at most 10% and even 1 to 6%.

[0104] For motor vehicle roofs, at least one or all of the following criteria are preferred: - an energy transmittance TE of up to 10% and even 4 to 6%, - Energy reflectivity RE of up to 10%, preferably 4 to 5% (preferably on the F1 side), - and a total solar transmittance TTS of <30% and even <26%, even 20 to 23%.

[0105] Laminated glazing can be used as windshields to provide combined solar control and heating functions, with advantageous optical reflective properties.

[0106] Finally, the glazing according to the invention is suitable for architectural applications, in particular when the glazing is used as a partition element from the outside. The glazing can be single-glazed, multi-glazed or laminated. Multi-glazing comprises the material according to the invention and a second substrate, separated by a gas layer.

[0107] In an advantageous embodiment, the functional coating can be used in combination with another functional coating, such as a low-e coating, in the laminated glazing. In this advantageous embodiment, the laminated glazing also features an additional functional coating. This additional functional coating is preferably located on face 4. This functional coating can include a conductive oxide layer (TCO).

[0108] This functional coating based on a conductive oxide layer advantageously has the following features: - the functional layer is selected from fluorine-doped tin oxide, antimony-doped tin oxide and / or indium tin oxide, - the functional layer has a geometric thickness of 70 to 200 nm, 75 to 150 nm, 80 to 130 nm or 90 to 110 nm, - the conductive oxide layer is preferably arranged between two dielectric coatings comprising at least one dielectric layer, The dielectric coating comprises a dielectric layer selected from the group consisting of a silicon oxide-based layer, a nitride-based layer of one or more elements selected from silicon, aluminum or zirconium, preferably a silicon nitride-based layer, a tin-zinc oxide-based layer, a zinc oxide-based layer or a titanium oxide-based layer.

[0109] Preferably, the conductive oxide coating is deposited on tinted glass.

[0110] This configuration comprising at least two functional coatings improves energy performance and, in particular, reduces the total solar transmittance (TTS) to below 14% with an exterior light reflectance of less than 20% and an exterior reflection color that is blue or neutral for any viewing angle.

[0111] The present invention also relates to a method for obtaining a material that exhibits no color change when covered by water droplets. The material comprises a transparent substrate having a functional coating. Preferably, the functional coating comprises, starting from the substrate, alternating between three silver-based functional metal layers (referred to as the first, second, and third functional layers, starting from the substrate); and four dielectric coating layers (referred to as Di1, Di2, Di3, and Di4, starting from the substrate, each having an optical thickness of Eo1, Eo2, Eo3, and Eo4), each dielectric coating layer comprising at least one dielectric layer, such that each functional metal layer is located between two dielectric coating layers.

[0112] Methods include: a) Steps for selecting functional coatings during this period, b) a step during which the parameters a*cd60 and b*cd60 of the external reflection characteristics of the colored droplet effect are determined, said parameters corresponding to the color in external reflection after reflection in the substrate at an angle of 60°, c1) If the parameters a*cd60 and b*cd60 do not satisfy a*cd60<10 and b*cd60<0, modify the functional coating. c2) If the parameters a*cd60 and b*cd60 satisfy a*cd60<10 and b*cd60<0, the functional coating is deposited on the substrate.

[0113] Details and advantageous features of the invention emerge from the following non-limiting examples. Example

[0114] I. Properties of Layers and Coatings The functional coating defined below was deposited on a substrate made of transparent soda-lime glass with a thickness of 2.1 mm.

[0115] The functional metal layer (FL) is a silver (Ag) layer. The barrier layer is a metal layer made of nickel-chromium alloy (NiCr). The dielectric coating of the functional coating comprises a barrier layer and a stabilization layer. The barrier layer is based on silicon nitride doped with aluminum (Si3N4:Al), silicon and aluminum-doped zirconium nitride (SiZr 17 N x ) or based on mixed zinc tin oxide (SnZnO x ). The stabilization layer is made of zinc oxide (ZnO).

[0116] The deposition conditions for the layers deposited by sputtering (“magnetron cathode” sputtering) are summarized in Table 1.

[0117] [Table 1] At. = Atom Table 2 lists the materials and the physical thickness in nanometers (unless otherwise stated) of each layer or coating forming the coating as a function of their position relative to the substrate carrying the stack (last row at the bottom of the table).

[0118] [Table 2] Di: dielectric coating; BL: barrier layer; FL: functional layer The optical thicknesses and thickness ratios of the functional layers and dielectric coatings are shown in Table 3. In this table, RFX corresponds to the thickness range explored by the simulations.

[0119] [Table 3] The substrate is subjected to a high temperature heat treatment, ie a treatment at a temperature exceeding 550° C. for several minutes.

[0120] II. Laminated Glazing Configuration Materials comprising a transparent substrate, one side of which is coated with a functional coating, have been assembled in the form of laminated glazings.

[0121] The laminated glazing, hereinafter referred to as "Lam.", had a structure of first substrate 2.1 mm / laminated interlayer / second substrate 2.1 mm.

[0122] The silver-based functional coating is located on side 2.

[0123] A low-E coating with a normal emissivity of 33% is located on face 4. An example of a low-E functional coating may include the following layer sequence: glass / / Si3N4 30 nm / SiO2 17 nm / InO2:Sn 72 nm / Si3N49 nm / SiO2 50 nm.

[0124] The interlayer is colored PVB or transparent PVB.

[0125] The second substrate is selected from clear glass or tinted glass, such as parsol ultragray venus (VG10) from Saint Gobain with a TL of 10%.

[0126] Table 4 shows the different laminate structures tested.

[0127] [Table 4] .

[0128] III. Exploratory Research Extensive studies were conducted using optical simulations to identify functional coatings that could potentially provide the desired optical and thermal properties.

[0129] In these simulations, the thicknesses of all layers were varied, with the exception of the zinc oxide layer and the zinc tin oxide layer.

[0130] The thickness range of each layer is defined as RFX in Table 2.

[0131] The results were obtained using an optical model developed for determining the “colored droplet” effect.

[0132] The results of these Brownian studies are shown in Figure 3 、 4 and 5 in.

[0133] Figure 3 、 4 and 5 show the distribution of functional coatings with the following properties: - "asterisks" correspond to functional coatings with TL > 68% and TTS < 38% and unacceptable CD effects, - "Circles" correspond to functional coatings with medium CD effect (<12.5;0), - “Cross” corresponds to functional coatings with weak CD effect (<10;-5).

[0134] Figure 3 The distribution of functional coatings having the combination of these properties is shown: TL>68%, TTS<38%, values ​​of a*Rext and b*Rext<0, and values ​​of a*60Rext and b*60Rext<0, as a function of the thickness of the following elements of the functional coating: - Thickness of functional layers Ag1, Ag2 and Ag3, - the thickness of all nitride layers present in the dielectric coatings Di1 , Di2, Di3, Di4, said nitride layers being respectively referred to as NDi1 , NDi2, NDi3, NDi4.

[0135] For example, NDi2 contains the sum of the thicknesses of the Si3N4 and SiZrN layers in the Di2 dielectric coating.

[0136] In this figure, given the density of the results, the set of "asterisks" corresponds to the light gray surface, the set of "circles" corresponds to the dark gray surface, and the set of "crosses" corresponds to the black surface.

[0137] Figure 3 It is clearly shown that for each element considered, a moderate or weak CD effect can be achieved only for a restricted thickness range. The most favourable combination of properties is obtained with Ag3 < Ag1 , Ag3 < Ag2, Ag2 > Ag1 and Eo2 > Eo3.

[0138] Figure 4 and 5 The distribution of functional coatings with unacceptable, moderate, and weak BP effects is shown, respectively: - varies with the thickness of Ag1 and Ag2, - Varies with the thickness of Ag1 and Ag3.

[0139] Figure 4 It is clearly shown that a moderate or non-existent colored droplet effect is obtained in the following cases: - the second functional layer is thicker than the first functional layer, and / or - a thickness variation of at least 0.5 nm, at least 1.0 nm, preferably at least 1.5 nm, and / or - the first functional layer has a thickness of 11 nm to 13.5 nm, and / or - The second functional layer has a thickness of 12.5 nm to 14.5 nm.

[0140] Figure 5 It is clearly shown that a moderate or non-existent colored droplet effect is obtained in the following cases: - the first functional layer is thicker than the third functional layer, and / or - a thickness variation of at least 0.5 nm, at least 1.0 nm, preferably at least 1.5 nm, and / or - the first functional layer has a thickness of 11 nm to 13.5 nm, and / or - The third functional layer has a thickness of 9.5 nm to 11.5 nm.

[0141] III. "Sunlight Control" and Chromaticity Performance Performance and colorimetric properties were determined by simulation.

[0142] [Table 5] .

Claims

1. A material comprising a transparent substrate coated with a functional coating, the functional coating comprising, starting from the substrate: Three alternating silver-based functional metal layers, referred to as the first, second, and third functional layers starting from the substrate; and four dielectric coatings, referred to as Di1, Di2, Di3 and Di4 starting from the substrate, each having an optical thickness Eo1, Eo2, Eo3 and Eo4, each dielectric coating comprising at least one dielectric layer, such that each functional metal layer is located between two dielectric coatings, characterized in that: - the ratio of the thickness of the second functional metal layer to the thickness of the first functional metal layer Ag2 / Ag1 is greater than or equal to 1.05, - the ratio of the thickness of the first functional metal layer to the thickness of the third functional metal layer Ag1 / Ag3 is greater than 1.05, - The ratio of optical thickness Eo2 / Eo3 is greater than 1.

00.

2. The material according to claim 1, characterized in that At least a ratio Ag2 / Ag1 of the thickness of the second functional metal layer to the thickness of the first functional metal layer or a ratio Ag1 / Ag3 of the thickness of the first functional metal layer to the thickness of the third functional metal layer is greater than 1.

10.

3. The material according to claim 1 or 2, characterized in that At least a ratio Ag2 / Ag3 of the thickness of the second functional metal layer to the thickness of the third functional metal layer is greater than 1.

15.

4. Material according to any one of the preceding claims, characterized in that: - the first silver-based functional metal layer has a thickness of 11 to 14 nm, and / or - the second silver-based functional metal layer has a thickness of 13 to 16 nm, and / or - The third silver-based functional metal layer has a thickness of 10.5 to 13 nm.

5. Material according to any one of the preceding claims, characterized in that: - the dielectric coating Di1 has an optical thickness Eo1 of 50 to 80 nm, - the dielectric coating Di2 has an optical thickness Eo2 of 160 to 180 nm, - the dielectric coating Di3 has an optical thickness Eo3 of 110 to 150 nm, - The dielectric coating Di4 has an optical thickness Eo4 of 70 to 90 nm.

6. Material according to the preceding claim, characterized in that: - The ratio of optical thickness Eo1 / Eo2 is less than 0.40, - The ratio of optical thickness Eo1 / Eo3 is less than 0.40, - The ratio of optical thickness Eo1 / Eo4 is less than 1.

00.

7. Material according to any one of the preceding claims, characterised in that Each dielectric coating comprises a silicon-containing layer selected from silicon nitride-based layers.

8. Material according to the preceding claim, characterised in that The sum of the physical thicknesses of all silicon-containing layers in each dielectric coating is greater than 25% of the total thickness of the dielectric coating.

9. Material according to any one of the preceding claims, characterised in that Each dielectric coating layer underlying the functional layer includes a zinc oxide-based layer underlying the functional layer, in contact with the functional layer, or separated from the functional layer by a barrier layer.

10. Material according to any one of the preceding claims, characterised in that Each dielectric coating layer overlying the functional layer includes a zinc oxide-based layer overlying the functional layer, in contact with the functional layer, or separated from the functional layer by a barrier layer.

11. Material according to any one of the preceding claims, characterised in that Each dielectric coating layer overlying the functional layer includes a zinc tin oxide-based layer underlying and in contact with the zinc oxide-based layer.

12. Laminated glazing comprising a material according to any one of the preceding claims and at least one second substrate, the material and the second substrate being connected to each other via a lamination interlayer.

13. Laminated glazing according to the preceding claim, characterized in that It comprises a face 1 on the outside of a building or vehicle equipped with the laminated glazing, faces 2 and 3 in contact with the laminate interlayer, and a face 4 on the inside of the building or vehicle, the functional coating being located on face 2.

14. Laminated glazing according to the preceding claim, characterized in that It additionally comprises a functional coating comprising a conductive oxide layer on face 4 .

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