Transparent substrate provided with a functional stack of thin layers

Abstract

The invention relates to a transparent substrate provided, on one of the main surfaces thereof, with a stack of thin layers, said stack consisting of the following layers, starting from the substrate: - a first dielectric module of one or more thin layers; - a titanium nitride-based layer; - a second dielectric module of one or more thin layers; wherein the first dielectric module and / or the second dielectric module comprises, starting from the substrate: - a first nitride-based thin layer; - an absorbent tungsten oxide-based layer; - a second nitride-based thin layer; said tungsten oxide comprising at least one dopant element selected from chemical elements from group 1 according to IUPAC nomenclature.

Description

Transparent substrate with a functional stack of thin layers

[0001] The invention relates to a transparent substrate provided with a functional stack of thin layers. Technical background

[0002] Functional stacks of thin films are commonly used to provide thermal insulation and / or solar protection functions to glazing in buildings. Their primary benefit is that they reduce air conditioning efforts by preventing excessive overheating (so-called "solar control" glazing) and / or by reducing the amount of energy dissipated to the outside (so-called "low-emissivity" glazing).

[0003] Solar control features are required for glazing that is likely to be exposed to high levels of sunlight. The ability of a glazing to limit the amount of light energy transmitted is defined by the solar factor, g, which is the ratio of the total energy transmitted through the glazed surface or glazing to the interior to the incident solar energy. The lower the value of the solar factor, g, the better the protection against solar radiation.

[0004] EP 0 239 280 A2 [GORDON ROY GERALD] 30.09.1987 describes a transparent glass substrate provided with a stack of thin layers comprising, starting from the substrate, a first layer of fluorine-doped tin oxide, a layer of titanium nitride and a layer of tin oxide. The stack provides solar control properties with a reduction in light reflection and coloration.

[0005] WO 2018 / 129135 A1[GUARDIAN GLASS LLC [US]] 12.07.2018 describes a transparent glass substrate provided with a stack of thin films comprising three thin films of silicon nitride between which are intercalated two thin films based on infrared reflective titanium nitride. The stack provides solar control properties with a reduction of the red color in reflection, maintenance of chemical and mechanical durability and low emissivity.

[0006] WO 2020 / 128327 A1 [SAINT GOBAIN [FR]] 25.06.2020 also describes a transparent glass substrate provided with a stack of thin layers comprising three thin layers of silicon nitride between which are intercalated two thin layers based on titanium nitride reflecting infrared radiation. The stack provides solar control and exterior invisibility properties so that the occupants of a building are not or are barely visible from the outside. The stack also has, in the La*b* system, a reflection coefficient a* of between 10 and -10.

[0007] WO 2021 / 170959 A1 [SAINT GOBAIN [FR]] 02.09.2021 describes a transparent glass substrate provided with a stack comprising two dielectric modules of layers between which are inserted a thin layer based on titanium nitride reflecting infrared radiation and a metallic intermediate layer based on silicon, aluminum, titanium or their mixture. The stack provides solar control properties with a light transmission greater than 30%, an emissivity less than 50%. The stack also has a certain chemical and mechanical durability when directly exposed.

[0008] JP 2010180449 A [SUMITOMO METAL MINING CO [JP]] 19.08.2010 discloses a tungsten oxide-based layer deposited by sputtering using a tungsten oxide target comprising chemical elements selected from hydrogen, alkali, alkaline earth, and rare earth. The layer has a "solar control" function due to its strong absorption of near-infrared radiation.

[0009] EP 3686312 A1 [SUMITOMO METAL MINING CO [JP]] 29.07.2020 describes a layer based on cesium-doped tungsten oxide, and a method for depositing such a layer by cathode sputtering. The layer has a “solar control” function thanks, in particular, to its strong absorption of infrared radiation.

[0010] A functional stack is considered suitable for such applications when it meets a triple requirement: high light transmission, low solar factor value and low emissivity value. A functional stack is therefore suitable when it has a high selectivity value, s, defined as the ratio of light transmission to solar factor, and low emissivity.

[0011] State-of-the-art solutions consisting of using only infrared radiation-absorbing layers as functional layers in the functional stack are not suitable because they have a higher emissivity, which is incompatible, for example, with applications in the residential market.

[0012] On the other hand, for applications in the residential market, particularly for use as single glazing, a functional stack must have a certain chemical and mechanical durability, particularly when in contact with the external environment.

[0013] There also remains a need to improve the energy performance of thin film stacks not comprising infrared-reflecting metal functional layers, in particular not comprising silver-based metal functional layers.

[0014] More specifically, there remains a need for a stack with at least one titanium nitride-based layer reflecting infrared radiation, which exhibits high selectivity and suitable overall energy performance, particularly regarding emissivity. Solution to the technical problem

[0015] A first aspect of the invention relates to a transparent substrate as described in claim 1, the dependent claims being advantageous embodiments. The transparent substrate is provided on one of its main surfaces with a stack of thin layers, said stack consisting of the following layers from the substrate: - a first dielectric module of one or more thin layers; - a layer based on titanium nitride; - a second dielectric module of one or more thin layers; in which the first dielectric module and / or the second dielectric module comprises from the substrate: - a first thin layer based on nitride; - an absorbing layer based on tungsten oxide; - a second thin layer based on nitride; said tungsten oxide comprises at least one doping element selected from the chemical elements of group 1 according to the IUPAC nomenclature.

[0016] Advantageous embodiments are described in the detailed description.

[0017] According to a second aspect of the invention, there is provided a single glazing and a laminated glazing comprising a transparent substrate according to the first aspect of the invention.

[0018] According to a third aspect of the invention, there is provided a method such as manufacturing a transparent substrate according to the first aspect of the invention. Advantages of the invention

[0019] A remarkable advantage of glazing comprising a transparent substrate according to the invention is a gain of up to more than 10% in selectivity while maintaining a sufficient level of light transmission, greater than 65% in single glazing application, and an emissivity of 5 W / m².K or even lower.

[0020] Another advantage of the invention is that the functional stack has better durability, in particular thanks to the encapsulation of the tungsten oxide layer by nitride-based layers, as detailed in certain embodiments.

[0021] a schematic representation of an embodiment of the first aspect of the invention.

[0022] a schematic representation of a second embodiment of the first aspect of the invention. Detailed description of embodiments

[0023] It uses the following definitions and conventions.

[0024] The term "above" or "below" respectively, qualifying the position of a layer or set of layers and defined relative to the position of another layer or set, means that said layer or set of layers is closer to, or further away from, the substrate. These two terms, "above" and "below", in no way mean that the layer or set of layers that they qualify and the other layer or set in relation to which they are defined are in contact. They do not exclude the presence of other intermediate layers between these two layers. The expression "in contact" is explicitly used to indicate that no other layer is arranged between them.

[0025] Without any precision or qualification, the term "thickness" used for a layer corresponds to the physical, real or geometric thickness, e, of said layer. It is expressed in nanometers.

[0026] The expression "dielectric module" designates one or more layers in contact with each other forming a set of globally dielectric layers, that is to say that it does not have the functions of a metallic functional layer. If the dielectric module comprises several layers, these may themselves be dielectric. The physical, real or geometric thickness of a dielectric module of layers corresponds to the sum of the physical, real or geometric thicknesses of each of the layers that constitute it.

[0027] In the present description, the expressions "a layer of" or "a layer based on", used to qualify a material or a layer as to what it contains, are used equivalently. They mean that the mass fraction of the constituent that it comprises is at least 50%, in particular at least 70%, preferably at least 90%. In particular, the presence of minority or doping elements is not excluded.

[0028] By the term "transparent", used to describe a substrate, means that the substrate is preferably colorless, non-opaque and non-translucent in order to minimize light absorption and thus maintain maximum light transmission in the visible electromagnetic spectrum.

[0029] In the case of building glazing, in particular single glazing, "light transmission" means light transmission, noted TL, as defined and measured in section 4.2 of standard EN 410.

[0030] In the case of building glazing, the light transmission, TL, in the visible spectrum, the solar factor, g, and the selectivity, s, the internal reflection, Rint, and the external reflection, Rext, in the visible spectrum, as well as their methods of measurement and / or calculation are defined in the standards EN 410, ISO 9050 and ISO 10292 in the case of glazing.

[0031] In the case of laminated glazing, "thermal transmission factor", Ug, is understood to mean the thermal transmission factor as defined according to the EN 673 standards.

[0032] According to the IUPAC nomenclature, Group 1 of the chemical elements includes hydrogen and the alkali elements, i.e., lithium, sodium, potassium, rubidium, cesium, and francium.

[0033] The expressions "optical refractive index" and "optical extinction coefficient" mean the optical refractive index, n, and the optical extinction coefficient, k, as defined in the technical field, in particular according to the Forouhi & Bloomer model described in the work Forouhi & Bloomer, Handbook of Optical Constants of Solids II, Palik, ED (ed.), Academic Press, 1991, Chapter 7.

[0034] According to a first aspect of the invention, with reference to the, there is provided a transparent substrate 1000 provided on one of its main surfaces with a stack 1001 of thin layers, said stack 1001 is made up of the following layers from the substrate:- a first dielectric module 1002 of one or more thin layers;- a layer 1003 based on titanium nitride;- a second dielectric module 1004 of one or more thin layers;in which the first dielectric module 1002 and / or the second dielectric module 1004 comprises from the substrate 1001:- a first thin layer 1002a, 1004a based on nitride;- an absorbing layer 1002b, 1004b based on tungsten oxide;- a second thin layer 1002c, 1004c based on nitride;said oxide tungsten comprises at least one doping element selected from the chemical elements of group 1 according to the IUPAC nomenclature.

[0035] According to the first aspect of the invention, the first dielectric module 1002 and / or the second dielectric module 1004 comprise a layer 1002b, 1004b of tungsten oxide. Thus, according to a first embodiment variant, only the first dielectric module 1002 comprises a layer 1002b of tungsten oxide. According to a second embodiment variant, only the second dielectric module 1004 comprises a layer 1004b of tungsten oxide. According to a third embodiment variant, each of the dielectric modules 1002, 1004 comprises a layer 1002b, 1004b of tungsten oxide.

[0036] When the first dielectric module and the second dielectric module each comprise a tungsten oxide layer, the tungsten oxide of the two tungsten oxide layers may be of different composition.

[0037] The transparent substrate 1000 may preferably be planar. It may be of organic or inorganic nature, rigid or flexible. In particular, it may be a mineral glass, for example a soda-lime-silica glass.

[0038] Examples of organic substrates that can be advantageously used for implementing the invention may be polymeric materials such as polyethylenes, polyesters, polyacrylates, polycarbonates, polyurethanes, polyamides. These polymers may be fluorinated polymers.

[0039] Examples of mineral substrates that can be advantageously used in the invention may be mineral or glass-ceramic glass sheets. The glass may preferably be a soda-lime-silica, borosilicate, aluminosilicate or alumino-borosilicate type glass. According to a preferred embodiment of the invention, the transparent substrate 1000 is a soda-lime-silica mineral glass sheet.

[0040] According to the invention, the stack 1001 of thin layers does not comprise metallic functional layers reflecting infrared radiation, in particular not comprising silver-based metallic functional layers.

[0041] Preferably, the optical refractive index of the tungsten oxide layer 1002b, 1004b decreases monotonically with wavelength from a maximum value greater than 2.4 at 350 nm to a minimum value between 600 nm and 1400 nm such that the difference between the maximum value and the minimum value is greater than 0.8, preferably greater than 1.0, or even greater than 1.4.

[0042] In other words, the value of the optical refractive index decreases monotonically by at least 0.8, preferably by at least 1.0, or even at least 1.4 between a maximum value greater than 2.4 at 350 nm and a minimum value between 600 nm and 1400 nm. For example, the optical refractive index value may decrease monotonically by at least 0.8, preferably by at least 1.0, or even at least 1.4 between a maximum value greater than 2.4 at 350 nm and a minimum value less than 2.3 between 600 nm and 1400 nm, in particular between 800 nm and 1100 nm.

[0043] Although not particularly required to achieve the effects of the present invention, these optical refractive index values ​​may nevertheless be advantageous for improving color neutrality in transmission and reflection.

[0044] Preferably, the optical extinction coefficient of the tungsten oxide layer 1002b, 1004b may be less than 0.2 or even 0.1 at 500 nm and less than 2 or even less than 1.5 at 1200 nm. The selectivity can thus be favorably further increased.

[0045] The optical extinction coefficient and the optical diffraction index can vary depending on the nature and quantity of the doping element(s) selected from the group 1 elements according to the IUPAC nomenclature. However, it is currently difficult to establish a general behavior law for the optical extinction coefficient and the refractive index depending on the nature and / or quantity of the doping element(s).

[0046] According to certain particular embodiments, the layer 1002b, 1004b of tungsten oxide comprises the doping element X or the doping elements X1, X2,… in a proportion such that the molar ratio, X / W of said element on the tungsten, W, or the sum of the molar ratios of each element on the tungsten (X1+X2+…) / W is between 0.01 and 0.6, preferably between 0.02 and 0.3.

[0047] It has been found that these molar ratio values ​​can advantageously achieve the optical extinction coefficient and refractive index values ​​described in the preceding embodiments while limiting the amount of doping elements. In addition, a saving on the exploitation of mineral resources for doping elements may possibly result, as well as a reduction in costs.

[0048] According to certain embodiments, the tungsten oxide layer 1002b, 1004b comprises at least one doping element selected from hydrogen, lithium, sodium, potassium and cesium. Among the group 1 elements, these particular elements can make it possible to obtain the most optimal optical extinction coefficient and refractive index values ​​for the desired technical effects.

[0049] According to particularly preferred embodiments, the tungsten oxide layer 1002b, 1004b comprises cesium as a doping element, and the molar ratio of cesium to tungsten is between 0.01 and 0.4, preferably between 0.01 and 0.2. These embodiments make it possible to obtain the best performances with regard to the increase in selectivity, the preservation of neutral colors, and cost savings.

[0050] According to certain advantageous embodiments, the physical thickness of the layer(s) 1002b, 1004b of tungsten oxide may be between 6 nm and 350 nm, in particular between 20 nm and 250 nm, preferably between 40 nm and 200 nm. These thickness ranges are sufficient to obtain the remarkable advantages of the first aspect of the invention.

[0051] According to certain embodiments, the first 1002a, 1004a and the second 1002c, 1004c nitride-based thin layers of the first dielectric module 1002 and / or of the second dielectric module 1004 may be chosen from aluminum nitride, silicon and zirconium nitride, or silicon nitride optionally doped with aluminum, zirconium and / or boron.

[0052] According to preferred embodiments, the first 1002a, 1004a and second 1002c, 1004c nitride-based layers of the first 1002 and second 1004 dielectric modules are based on aluminum nitride or silicon nitride.

[0053] The first 1002a, 1004a and second 1002c, 1004c nitride-based layers of the first dielectric module 1002 and / or the second dielectric module 1004 are located on either side of the tungsten oxide-based layer 1002b, 1004b. The tungsten oxide-based layer 1002b, 1004b is then encapsulated.

[0054] This encapsulation provides double protection for the tungsten oxide-based absorbent layer 1002b, 1004b. On the one hand, it prevents possible contamination by elements likely to diffuse into the stack from the substrate, such as in particular alkali ions or oxygen in the case of a mineral glass substrate. On the other hand, it makes it possible to limit, in particular during an annealing heat treatment step, the diffusion of oxygen into the stack towards the tungsten oxide-based absorbent layer from the atmosphere and / or the substrate.

[0055] Thanks to the encapsulation, the chemical composition and the degree of oxidation of the tungsten oxide absorbing layer vary little over time, or if they vary, this variation is favorable for selectivity. On the other hand, when the stack is subjected to an annealing heat treatment, the encapsulation makes it possible to ensure a correct level of selectivity. In use, the substrate according to the first aspect of the invention is more durable, in particular its performance is preserved over the long term.

[0056] The first dielectric module 1002 and the second dielectric module 1004 may comprise additional thin layers. In particular, these additional layers may have chemical compositions making it possible to confer particular optical properties, for example in terms of colors or filtering of certain wavelengths of the electromagnetic spectrum, to the substrate. They may also confer certain mechanical and / or chemical properties, such as resistance to abrasion, delamination and / or chemical attack. These layers are generally based on oxides or oxynitrides of metals or metal alloys.

[0057] Depending on their composition and arrangement in the stack, these additional layers can be sources of contamination of the tungsten oxide-based absorbent layer. These sources of contamination can be a diffusion of certain metal ions or dopants or a diffusion of oxygen. They can occur during the deposition of the additional layers, during possible certain heat treatments of the stack, or during use.

[0058] Such contaminations can impair the tungsten oxide-based absorbent layer and are detrimental to the performance of the substrate according to the first aspect of the invention.

[0059] According to preferred embodiments, the first 1002a, 1004a and second 1002c, 1004c nitride-based layers of the first 1002 and second 1004 dielectric modules are in contact with the tungsten oxide layer 1002b, 1004b.

[0060] According to certain particular embodiments, the first dielectric module 1002 and / or the second dielectric module 1004 are made from the substrate 1000: - the first thin layer 1002a, 1004a based on nitride; - the absorbent layer 1002b, 1004b based on tungsten oxide; - the second thin layer 1002c, 1004c based on nitride.

[0061] When the first dielectric module 1002 and / or the second dielectric module 1004 are thus constituted, that is to say they comprise only the aforementioned nitride-based layers, the risk of alteration of the tungsten oxide-based absorbent layer by possible diffusion of oxygen is then limited, or even eliminated. The durability of the substrate according to the first aspect of the invention can then be maximized with regard to the desired “solar control” performances.

[0062] According to embodiments, the thickness of the titanium nitride layer 1003 is between 5 nm and 25 nm, preferably between 10 nm and 20 nm, the thickness of the tungsten oxide-based absorbing layer(s) is between 5 and 100 nm, preferably between 10 and 50 nm, and the thicknesses of the nitride-based layers 1002a, 1004a, 1002c, 1004c of the first 1002 and second 1004 dielectric modules are between 5 nm and 100 nm, preferably between 5 nm and 50 nm.

[0063] According to a second aspect of the invention, there is provided a single glazing unit comprising a substrate according to the first aspect of the invention. With reference to the, there is also provided a laminated glazing unit 2000 comprising a first transparent substrate 1000 according to the first aspect of the invention, a lamination interlayer 2001 and a second transparent substrate 2002, such that the first transparent substrate 1000 and the second transparent substrate 2002 are in adhesive contact with the lamination interlayer 2001 and the stack 1001 of thin layers of the first transparent substrate 1000 is in contact with the lamination interlayer 2001.

[0064] The lamination interlayer 2001 may be made of one or more layers of thermoplastic material. Examples of thermoplastic material are polyurethane, polycarbonate, polyvinyl butyral (PVB), polymethyl methacrylate (PMMA), ethylene vinyl acetate (EA), or an ionomer resin.

[0065] The lamination interlayer 2001 may be in the form of a multi-layer film. It may also have special features such as, for example, acoustic or anti-UV properties.

[0066] Typically, the lamination interlayer 2001 comprises at least one layer of PVB. Its thickness is between 50 µm and 4 mm. In general, it is less than 1 mm.

[0067] According to certain preferred embodiments, the laminated glazing 2000, when used as glazing for a motor vehicle, for example as a windshield, is such that the substrate 1000 according to the first aspect of the invention is located inside the vehicle. In other words, the stack is placed on face 2 of the glazing from the substrate 1000 oriented towards the inside of the vehicle, face 1 being the face oriented towards the inside; or on face 3 of the glazing from the substrate 1000 oriented towards the outside of the vehicle, face 1 being the face oriented towards the outside.

[0068] According to certain embodiments, the second substrate 2002 may be a mass-tinted mineral glass. The mass-tinting or coloring of a mineral glass is known and extensively detailed in the technical literature. Coloring can generally be achieved by adding coloring oxides to the glass chemical composition. Examples of coloring oxides may be 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 complex, may also be used.

[0069] Laminated glazing manufacturing processes are well known in the glass industry. For example, a laminated glazing manufacturing process may be a process of laminating a lamination interlayer between two glass sheets. The glass sheets may be pre-shaped, for example, in a curved manner using a bending process. They may also be coated with one or more thin-film coatings using any suitable type of thin-film deposition process.

[0070] The processes for depositing thin layers on substrates, in particular glass sheets, are well-known processes in the industry. For example, the deposition of a stack of thin layers on a glass substrate is carried out by successively depositing each thin layer of said stack by passing the glass substrate through a succession of deposition cells adapted to deposit a given thin layer.

[0071] 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-enhanced chemical vapor deposition (PECVD), low-pressure chemical vapor deposition (LPCVD), etc.

[0072] The magnetic field-assisted sputtering deposition process is particularly used. The conditions for deposition of layers are widely documented in the literature, for example in patent applications WO2012 / 093238 A1 and WO2017 / 00602 A1.

[0073] According to a third aspect of the invention, a method of manufacturing a substrate 1000 according to the first aspect of the invention is provided, such that the layer(s) 1002b, 1004c of tungsten oxide are deposited by a magnetron sputtering method using a tungsten oxide target doped with a chemical element chosen from the chemical elements of group 1 according to the IUPAC nomenclature.

[0074] The tungsten oxide target may in particular contain one or more doping elements in a proportion as described for the doped tungsten oxide layer in certain embodiments of the first aspect of the invention.

[0075] The tungsten oxide layer 1002b, 1004b can be deposited by sputtering using the above-mentioned target under a deposition atmosphere composed of 60-100% argon and 0-40% dioxygen, preferably 70-85% argon and 15-30% dioxygen.

[0076] The tungsten oxide layer 1002b, 1004b may be deposited under a pressure of between 1 and 15 mTorr, preferably 3 to 10 mTorr.

[0077] Preferably, the deposition can be carried out cold, that is to say at a temperature below 100°C, in particular between 20°C and 60°C, for the substrate.

[0078] The deposition can also be carried out hot, in particular at a temperature between 100°C and 400°C.

[0079] According to particular embodiments, the substrate 1000, after deposition of the stack 1001, may undergo an annealing heat treatment. The annealing temperature may 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 may be between 5 min and 30 min, in particular between 5 min and 20 min, or even between 5 min and 10 min.

[0080] All the embodiments described, whether they relate to the first or second aspect of the invention, can be combined with each other without any particular modification or adaptation. In the event that technical incompatibilities appear during the implementation of one of these combinations, it is within the reach of those skilled in the art to be able to resolve them using their knowledge without this requiring undue effort, in particular by implementing a research program. Examples

[0081] The features and advantages of the present invention are illustrated by the non-limiting examples described below.

[0082] Two examples, E1-E2, in accordance with the invention, and two counter-examples, CE1 and CE2, not in accordance with the invention, are described in Table 1 which indicates the composition and the thickness expressed in nanometers of the different layers. The numbers in the first two columns correspond to the references in the figures.

[0083] The layer, denoted CWO, is made of cesium-doped tungsten oxide. The molar ratio of cesium to tungsten in the layer is approximately 0.05-0.06.

[0084] Tab. 1 E1 E2 CE1 1004SiN291141CWO2029SiN551003TiN9,812,89,81002SiN55CWO910SiN3333331000 glass 6mm 6mm 6mm

[0085] Counterexample CE1 differs from the examples by the absence of a tungsten oxide layer.

[0086] The thin layers of the functional coatings 1004 of examples E1 to E3 and of counter-examples CE1 and CE2 were deposited by cathodic sputtering assisted by a magnetic field (magnetron process) whose characteristics are widely documented in the literature, for example in patent applications WO2012 / 093238 and WO2017 / 00602.

[0087] The nature of the targets used and the deposition conditions of examples E1 to E2 and counter-example CE1 are described in Table 2.

[0088] The functional coatings 1001 are deposited directly onto the glass sheet 1000. This glass sheet 1000 is a 6 mm thick soda-lime-silica mineral glass sheet. Immediately after deposition, the functional coatings were subjected to a heat treatment at 650°C for 10 min.

[0089] Tab. 2 Target Pressure (µbar) Ar (sccm) O2 (sccm) N2 (sccm) Power (W) TiNTi2320152500SiN Si:Al570142000CWOCWO: Cs / W 0.3-0.44-1030-402-1001300

[0090] The solar factor, g, the selectivity, s, the light transmission, Tl, the light reflection on the inner face, Rint, and on the outer face, Rext, as well as the color in transmission, on the inner face and on the outer face, and the emissivity were measured for each example E1 to E2 and the counter-examples CE1.

[0091] The luminous transmission in the visible spectrum, TL, the solar factor, g, the selectivity, s, and the internal reflection, Rint, and the external reflection, Rext, in the visible spectrum are defined, measured and calculated in accordance with the standards EN 410, ISO 9050 and / or ISO 10292.

[0092] Emissivity, Ug, is defined, measured and calculated in accordance with EN 410 and EN 12898 standards.

[0093] The term "color," used to describe a transparent substrate with a stack, means the color as defined in the CIE 1976 L*a*b* color space according to ISO 11664, in particular with a D65 illuminant and a visual field of 2° or 10° for the reference observer. It is measured in accordance with said standard.

[0094] The measurements of emissivity, solar factor, selectivity, light transmission, internal reflection, external reflection, color parameters a* and b*, in transmission (a*T, b*T), in external reflection (a*Rext, b*Rext) and in internal reflection (a*Rint, b*Rint) are grouped in Table 3.

[0095] Tab. 3E1E2CE1g57,256.061,5s1,151,181,07TL66.066.066.0a*T-3,8-3,6-1,3b*T-3,9-2,7-2,4Rext12,115,815 ,0a*Rext-3,7-5,1-2,1b*Rext-0,10,0-2,1Rint7,99,612,1a*Rint2,02,0-4,0b*Rint6,04,16,1Ug5,04,85,0

[0096] Compared to the counterexample CE1, examples E1 and E2 have a lower solar factor for the same light transmission. Their selectivity is therefore higher. The thermal transmittance of examples E1 and E2 is similar to that of the counterexample, or even slightly lower for example E1. The parameters a* and b* are close to zero in both transmission and reflection, indicating that examples E1 and E2 have a relatively neutral color in transmission and / or reflection.

[0097] Examples E1 and E2 also exhibit lower, if not comparable, levels of internal and external reflection to those of counterexample CE1.

[0098] The stacks 1001 of examples E1 to E2 and of counter-example CE1 were also used to form laminated glazing, noted respectively VFE1, VFE2 and VFCE1.

[0099] The 1001 functional coatings were deposited under the same conditions as before on 4 mm thick 1000 sheets of soda-lime-silica mineral glass. Immediately after deposition, the functional coatings were subjected to a heat treatment at 650°C for 10 min.

[0100] Once the deposition and heat treatment are complete, each of the glass sheets 1000 provided with a functional coating 1001 is laminated with a lamination interlayer 2001 made of PVB with a thickness of 0.38 mm and a second glass sheet 2002 made of soda-lime-silica mineral glass with a thickness of 4 mm in order to form a laminated glazing according to the diagram of the.

[0101] The solar factor, g, the selectivity, s, the light transmission, Tl, the light reflection on the inner side, Rint, and on the outer side, Rext, as well as the color in transmission, on the inner side and on the outer side, and the emissivity were measured for each example VFE1 to VFE2 and the counter-examples VFCE1.

[0102] Luminous transmission in the visible spectrum, TL, solar factor, TTS, selectivity, s, and internal reflection, Rint, and external reflection, Rext, in the visible spectrum are defined, measured and calculated in accordance with ISO 13837:2021 – convention A.

[0103] The thermal transmittance, Ug, is defined, measured and calculated in accordance with standard EN 673.

[0104] The term "color," used to describe a transparent substrate with a stack, means the color as defined in the CIE 1976 L*a*b* color space according to ISO 11664, in particular with a D65 illuminant and a visual field of 2° or 10° for the reference observer. It is measured in accordance with said standard.

[0105] The measurements of emissivity, solar factor, selectivity, light transmission, internal reflection, external reflection, color parameters a* and b*, in transmission (a*T, b*T), in external reflection (a*Rext, b*Rext) and in internal reflection (a*Rint, b*Rint) are grouped in Table 4.

[0106] Tab. 4VFE1VFE2VFCE1g58,856,157,9s1,161,191,14TL68,366,566a*T-4,0-4,0-3,4b*T0,00,00,0Rext8,112,78 ,0a*Rext0,9-3,60,5b*Rext-2,3-0,10,0Rint7,27,28,1a*Rint1,41,90,3b*Rint-5,0-6,40,5Ug5,65,65,6

[0107] Compared to the counterexample VFCE1, examples VFE1 and VFE2 exhibit higher selectivity. The emissivity of examples E1 and E2 is similar to that of the counterexample. The parameters a* and b* are close to zero in both transmission and reflection, indicating that examples E1 and E2 exhibit relatively neutral color in transmission and / or reflection.

[0108] These examples very clearly illustrate the advantages of the substrates and glazings according to the invention, namely that they have higher selectivity and have a neutral color.

Claims

A transparent substrate (1000) provided on one of its principal surfaces with a stack (1001) of thin films, said stack (1001) being composed of the following layers from the substrate: - a first dielectric module (1002) of one or more thin films; - a layer (1003) based on titanium nitride; - a second dielectric module (1004) of one or more thin films; wherein the first dielectric module (1002) and / or the second dielectric module (1004) comprises from the substrate (1001): - a first thin film (1002a, 1004a) based on nitride; - an absorbing layer (1002b, 1004b) based on tungsten oxide; - a second thin film (1002c, 1004c) based on nitride; said tungsten oxide comprises at least one element doping selected from the chemical elements of group 1 according to the IUPAC nomenclature. Substrate according to claim 1, such that layer (1002b, 1004b) of tungsten oxide comprises the dopant element X or the dopant elements X1,X2,… in proportions such that the molar ratio, X / W of said element to tungsten, W, or the sum of the molar ratios of each element to tungsten (X1+X2+…) / W is between 0.01 and 0.6, preferably between 0.02 and 0.

3. Substrate according to any one of claims 1 to 2, wherein the tungsten oxide layer (1002b, 1004b) comprises at least one dopant element selected from hydrogen, lithium, sodium, potassium and cesium. Substrate according to claim 3, wherein the tungsten oxide layer (1002b, 1004b) comprises cesium as a dopant element, and the molar ratio of cesium to tungsten is between 0.01 and 0.4, preferably between 0.01 and 0.

2. Substrate according to any one of claims 1 to 4, such that the physical thickness of the tungsten oxide layer(s) (1002b, 1004b) can be between 6 nm and 350 nm, in particular between 20 nm and 250 nm, preferably between 40 nm and 200 nm. Substrate according to any one of claims 1 to 5, wherein the first (1002a, 1004a) and second (1002c, 1004c) nitride-based layers of the first (1002) and second (1004) dielectric modules are based on aluminium nitride or silicon nitride. Substrate according to any one of claims 1 to 6, such that the first (1002a, 1004a) and second (1002c, 1004c) nitride-based layers of the first (1002) and second (1004) dielectric modules are in contact with the tungsten oxide layer (1002b, 1004b). Substrate according to any one of claims 1 to 7, wherein the first dielectric module (1002) and / or the second dielectric module (1004) are constituted from the substrate (1000) of: - the first thin layer (1002a, 1004a) based on nitride; - the absorbing layer (1002b, 1004b) based on tungsten oxide; - the second thin layer (1002c, 1004c) based on nitride. Transparent substrate according to any one of claims 1 to 8, wherein the thickness of the titanium nitride layer (1003) is between 5 nm and 100 nm, preferably between 10 nm and 50 nm, the thickness of the tungsten oxide-based absorbing layer(s) is between 5 and 100 nm, preferably between 10 and 50 nm, and the thicknesses of the nitride-based layers (1002a, 1004a, 1002c, 1004c) of the first (1002) and second (1004) dielectric modules are between 5 nm and 100 nm, preferably between 5 nm and 50 nm. Single glazing comprising a substrate according to any one of claims 1 to 9. Laminated glazing (2000) comprising a first transparent substrate (1000) according to any one of claims 1 to 9, a lamination interlayer (2001) and a second transparent substrate (2002), wherein the first transparent substrate (1000) and the second transparent substrate (2002) are in adhesive contact with the lamination interlayer (2001) and the stack (1001) of thin layers of the first transparent substrate (1000) is in contact with the lamination interlayer (2001). Method of manufacturing a transparent substrate according to any one of claims 1 to 9, wherein the layer(s) (1002b, 1004c) of tungsten oxide are deposited by a magnetron sputtering method using a tungsten oxide target doped with a chemical element selected from the chemical elements of group 1 according to the IUPAC nomenclature. Manufacturing process according to claim 12, wherein the tungsten oxide absorbent layer(s) is deposited at a substrate temperature below 100°C, preferably between 20 and 60°C. A manufacturing process according to any one of claims 12 to 13, wherein the tungsten oxide-based layer is deposited in a deposition atmosphere composed of 60 to 100% argon and 0 to 40% dioxygen, preferably 70 to 85% argon and 15 to 30% dioxygen. A manufacturing process according to any one of claims 12 to 14, wherein the tungsten oxide layer is deposited at a pressure between 1 and 15 mTorr, preferably between 3 and 10 mTorr.

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