Transparent substrates provided with thin functional stacks

Abstract

The present invention relates to a transparent substrate provided on one of its main surfaces with a thin layer stack, said stack of layers consisting, starting from the substrate, of the following layers: - a first dielectric module of one or more thin layers; - a tungsten oxide absorbing layer; - a second dielectric module of one or more thin layers; in which the tungsten oxide comprises at least one doping element selected from the chemical elements of group 1 according to the IUPAC nomenclature.

Description

[Technical field]

[0001] The present invention relates to a transparent substrate that is provided with a stack of thin layers that impart "sun control" properties. [Background technology]

[0002] Thin functional stacks are commonly used to provide thermal insulation and / or solar protection to architectural glazing, in particular to reduce the effort required for air conditioning and / or to reduce extreme overheating (so-called "solar control" glazing) and / or to reduce the amount of energy dissipated to the outside (so-called "low emissivity" glazing).

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

[0004] When radio frequency transparent properties are desired, it is common to use "solar control" glazings provided with a stack of thin layers excluding the functional metallic layer. Instead of the functional metallic layer, functional layers that absorb infrared radiation are generally used. These can be based on oxides and / or nitrides.

[0005] JP 2010-180449 [Sumitomo Metal Mining Co., Ltd. (Japan)] 2010 / 08 / 19 describes a layer based on tungsten oxide deposited by sputtering using a tungsten oxide target containing chemical elements selected from hydrogen, alkali metals, alkaline earth metals and rare earth metals. This layer has a "solar control" function thanks to its high absorption of near infrared radiation.

[0006] EP 3686312 [Sumitomo Metal Mining Co., Ltd. (Japan)] 2020 / 07 / 29 describes a layer based on cesium oxide doped with cesium and a method for depositing such a layer by sputtering, which has transparency to radio waves and a "solar control" function, in particular due to its high absorption of infrared radiation. Summary of the Invention [Problem to be solved by the invention]

[0007] A functional stack is described as suitable for architectural applications if it meets the following dual requirements: high light transmittance and low solar factor value. A functional stack is therefore suitable if it has a selectivity value s, which is defined as the ratio of light transmittance to high solar factor.

[0008] Furthermore, it is preferred that the functional stack has a certain chemical and mechanical durability for certain applications, especially in single glazing, when it is directly exposed to the exterior or interior environment of a building.

[0009] There also remains a need to improve the energy performance of thin layer stacks that do not include any functional metal layers that reflect infrared radiation, particularly thin layer stacks that do not include silver-based functional metal layers.

[0010] Radio frequency transparency may further be desirable. [Means for solving the problem]

[0011] A first aspect of the invention relates to a transparent substrate as claimed in claim 1, the dependent claims being advantageous embodiments.

[0012] The transparent substrate according to the invention is provided on one of its main surfaces with a thin layer stack, said layer stack consisting, starting from the substrate, of the following layers: - a first dielectric module of one or more thin layers; - Absorbent tungsten oxide layer; - a second dielectric module of one or more thin layers; Here, the tungsten oxide comprises at least one doping element selected from the chemical elements of group 1 according to the IUPAC nomenclature.

[0013] Other advantageous embodiments are presented in the detailed description.

[0014] A second aspect of the invention relates to a glazing comprising a transparent substrate according to the first aspect of the invention.

[0015] A third aspect of the present invention relates to a method for producing a transparent substrate according to the first aspect of the present invention. Effect of the Invention

[0016] Notable advantages of glazing comprising a transparent substrate according to the invention are sufficient light transmission, greater than 65% in single glazing applications, and a light transmittance of 5 W / m 2 The aim is to increase the selectivity by up to 10% more while maintaining a heat transfer coefficient Ug of 0.5 -K or even less.

[0017] Another advantage of the present invention is that the functional stack has relatively good mechanical and chemical durability and maintains its optical and energetic performance even after thermal treatment, in particular due to the encapsulation of the tungsten oxide layer by a nitride-based layer, as detailed in some embodiments. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a schematic diagram of a first embodiment of the first aspect of the present invention.

[0019] [Diagram 2] FIG. 2 is a schematic diagram of a first embodiment of a double glazing according to a second aspect of the invention.

[0020] [Diagram 3]FIG. 3 is a schematic diagram of a second embodiment of the double glazing according to the second aspect of the invention.

[0021] [Figure 4] FIG. 4 is a schematic diagram of a laminated glazing according to a second embodiment of the invention.

[0022] [Diagram 5] FIG. 5 is a schematic diagram of light transmittance and solar factor for several examples of glazing according to the invention and three comparative examples.

[0023] [Figure 6] FIG. 6 is a schematic diagram of light reflection on the internal and external surfaces for some examples of glazing according to the invention and three comparative examples.

[0024] [Figure 7] FIG. 7 is a schematic diagram of the color parameters a* and b* in transmission, internal reflection and external reflection for some examples of glazing according to the invention and three comparative examples.

[0025] [Figure 8] FIG. 8 is a schematic diagram of light transmittance and solar factor for several examples of laminated glazing according to the invention and three comparative examples.

[0026] [Figure 9] FIG. 9 is a schematic diagram of light reflection on the internal and external surfaces for some examples of laminated glazing according to the invention and three comparative examples.

[0027] [Figure 10] FIG. 10 is a schematic diagram of the color parameters a* and b* in transmission, internal reflection and external reflection for some examples of laminated glazing according to the invention and three comparative examples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Detailed Description of the Embodiments

[0029] The following definitions and conventions are used:

[0030] The terms "above" and "below", respectively, describe the location of a layer or assembly of layers and are defined in relation to the location of another layer or another assembly, meaning that said layer or said assembly of layers is relatively closer to and relatively farther from the substrate, respectively.

[0031] These two terms, "above" and "below", do not imply any contact between the layer or assembly of layers they describe and the other layer or assembly for which they are defined. They do not exclude the presence of other intermediate layers between these two layers. The expression "in contact" is used explicitly to indicate that no other layers are disposed between them.

[0032] The term "thickness" used for a layer, without any relative completeness or qualifier, corresponds to the physical, actual or geometric thickness e of said layer, which is expressed in nanometers.

[0033] The expression "dielectric module" denotes one or more layers in contact with each other forming an assembly of layers that are dielectric as a whole, i.e. do not have the function of a functional metal layer. If the dielectric module has several layers, they 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 compose it.

[0034] In this specification, the expressions "layer of" or "layer based on" are used to describe a material or layer in terms of what it contains, and are used equivalently. They mean that it contains a mass fraction of at least 50%, in particular at least 70%, preferably at least 90% of the component. In particular, the presence of minor elements or doping elements is not excluded.

[0035] The term "transparent" as used to describe the substrate means that the substrate is preferably colorless, non-opaque, and non-translucent, thereby minimizing light absorption and thus retaining maximum light transmission in the visible electromagnetic spectrum.

[0036] "Light transmission" is understood to mean the light transmission as defined and measured in section 4.2 of standard EN 410 and denoted TL.

[0037] The light transmittance in the visible spectrum TL, the solar factor g and the selectivity s, the internal reflectance in the visible spectrum Rint and the external reflectance Rext are defined, measured and calculated in accordance with standards EN 410, ISO 9050 and ISO 10292.

[0038] In the case of laminated glazing, “heat transmission coefficient” Ug is understood to mean the heat transmission coefficient defined in accordance with standard EN 673.

[0039] According to the IUPAC nomenclature, group 1 of the chemical elements includes hydrogen and the alkali elements, namely lithium, sodium, potassium, rubidium, cesium, and francium.

[0040] The expressions "optical refractive index" and "optical extinction coefficient" are understood as the optical refractive index n and the optical extinction coefficient k as defined in the art, in particular according to Forouhi & Bloomer, Handbook of Optical Constants of Solids II, Palik, ED (ed.), Academic Press, 1991, Chapter 7.

[0041] According to a first embodiment of the invention, with reference to FIG. 1, a transparent substrate 1000 is provided, having on one of its main surfaces a thin layer stack 1001, said layer stack 1001 consisting, starting from the substrate 1000, of the following layers: - a first dielectric module 1002 of one or more thin layers; - an absorbent layer of tungsten oxide 1003; - a second dielectric module 1004 of one or more thin layers;

[0042] The tungsten oxide contains at least one doping element selected from the chemical elements of group 1 according to the IUPAC nomenclature.

[0043] The absorbing tungsten oxide layer 1003 is a layer that absorbs infrared radiation, preferably infrared radiation having a wavelength greater than 780 nm.

[0044] Surprisingly, an absorbing layer 1003 of tungsten oxide containing a doping element selected from the elements of group 1 according to the IUPAC nomenclature, enclosed between two dielectric modules, makes it possible to increase the selectivity.

[0045] The stack 1001 of transparent substrates 1000 according to the first embodiment of the present invention does not include a functional metallic layer.

[0046] According to one particular embodiment, the absorbing tungsten oxide layer 1003 may comprise a doping element X or doping elements X1, X2, ... in such a proportion that the molar ratio of said element on tungsten, X / W, or the sum of the molar ratios of each element on tungsten, (X1+X2+...) / W, is between 0.01 and 1, preferably between 0.01 and 0.6, or even between 0.02 and 0.3.

[0047] It has been observed that these values ​​of molar ratios can make it possible to obtain optimal selectivity values ​​whilst making it possible to limit the amount of doping element used, thus making it possible to generate savings in the use of inorganic resources for the doping element and a reduction in production costs.

[0048] According to a particular embodiment, the absorbing layer 1003 of tungsten oxide may contain at least one doping element selected from hydrogen, lithium, sodium, potassium, and cesium.

[0049] Among the elements of the first group, these particular elements may make it possible to obtain advantageous selectivity values, ie relatively high values.

[0050] According to particularly preferred embodiments, the absorbing layer of tungsten oxide 1003 may contain cesium as a doping element, the molar ratio of cesium to tungsten being between 0.01 and 1, preferably between 0.05 and 0.4. These embodiments make it possible to obtain the best performance in terms of improved selectivity, color retention and reduced costs.

[0051] According to a particular embodiment, the thickness of the absorbing layer of tungsten oxide 1003 may be between 6 and 450 nm, preferably between 20 and 250 nm, or even between 40 and 200 nm.

[0052] The transparent substrate 1000 may preferably be planar. It may be of organic or inorganic nature, rigid or flexible. In particular, it may be an inorganic glass, such as soda-lime-silica glass.

[0053] Examples of organic substrates that may be advantageously used in the practice of the present invention include polymeric materials such as polyethylene, polyester, polyacrylate, polycarbonate, polyurethane, or polyamide, etc. These polymers may be fluoropolymers.

[0054] Examples of inorganic substrates that may be advantageously employed in the present invention include sheets of inorganic glass or glass ceramic. The glass may preferably be soda-lime-silica, borosilicate, aluminosilicate or other aluminoborosilicate type glass. According to a preferred embodiment of the present invention, the transparent substrate 1000 is a sheet of soda-lime-silica inorganic glass.

[0055] According to certain embodiments, the first dielectric module 1002 and / or the second dielectric module 1004 may have one or more layers based on nitrides and / or oxides, preferably based on zinc and tin oxides, zinc oxide, titanium oxide, zirconium oxide, aluminum nitride, nitrides of silicon and zirconium, or silicon nitride, optionally doped with aluminum, zirconium and / or boron.

[0056] According to an advantageous embodiment, the first dielectric module 1002 and / or the second dielectric module 1004 consists of one or more nitride-based layers. According to an example embodiment, the one or more nitride-based layers of the first dielectric module 1002 and / or the second dielectric module 1004 are selected from aluminum nitride, silicon nitride, titanium nitride, niobium nitride, silicon zirconium nitride, silicon nitride doped with aluminum, zirconium and / or boron.

[0057] When one or more layers of the first dielectric module 1002 and the second dielectric module 1004 are based on nitride, they make it possible to encapsulate an absorbing layer based on tungsten oxide.

[0058] This encapsulation makes it possible to provide a double protection for the absorbing layer based on tungsten oxide 1003: on the one hand, it prevents any contamination by elements capable of diffusing from the substrate 1000 into the stack 1001, such as, in particular, alkali metal ions or, in the case of heavy inorganic glass substrates, oxygen, etc. On the other hand, it makes it possible to limit the diffusion of oxygen from the atmosphere and / or the substrate towards the absorbing layer based on tungsten oxide 1003 into the stack 1001, in particular during thermal treatment steps of the annealing type.

[0059] Thanks to the encapsulation, the chemical composition and degree of oxidation of the tungsten oxide absorbing layer 1003 changes little over time, or if it does change, this change is favorable for selectivity. Furthermore, the encapsulation ensures an adequate level of selectivity when the stack is subjected to an annealing heat treatment. In use, the substrate 1000 according to the first aspect of the invention is relatively durable, in particular its performance is maintained over time.

[0060] A second aspect of the invention relates to glazing, in particular single, double or triple glazing, and laminated glazing, comprising a transparent substrate according to the first aspect of the invention.

[0061] According to a second aspect of the invention, there is provided a single or double glazing comprising a substrate according to the first aspect of the invention.

[0062] Single glazing, i.e. monolithic glazing, has a single substrate, in particular an inorganic glass sheet. When the substrate according to the invention is used as a monolithic glazing, this functional stack of layers is preferably deposited on the side of the substrate facing the interior of the building room, on the wall of the building on which the glazing is installed. In such a configuration, it may be advantageous to protect the first layer and optionally the stack of thin layers from physical or chemical damage using suitable measures.

[0063] A multi-layer glazing has at least two substrates, in particular inorganic glass sheets, which are arranged in parallel and separated by a barrier gas-filled cavity. The majority of multi-layer glazings are double or triple glazings, i.e. they have two or three glazings, respectively. When the substrate according to the invention is used as an element of a multi-layer glazing, the functional stack of thin layers is preferably deposited on the side of the glass sheet that is in contact with the barrier gas and faces inwards. This arrangement has the advantage of protecting the stack from chemical or physical damage from the external environment.

[0064] According to a preferred embodiment, with reference to Figures 2 and 3, the glazing is a double glazing 2000, 3000, comprising a transparent substrate 1000 according to any one of the embodiments disclosed above, such that a functional stack of layers 1001 is arranged facing two and / or three of said glazings 9000, 10000. In the figures, (E) corresponds to the exterior of the premises where the glazing is installed and (I) corresponds to the interior of the premises.

[0065] According to a first embodiment, and referring to FIG. 2 , a glazing 2000 has a first transparent glass sheet 1000 having an inner surface 1000a and an outer surface 1000b, a second glass sheet 2001 having an inner surface and an outer surface, an insulating gas-filled cavity 2002, a spacer 2003, and a seal 2004.

[0066] The glass sheet 1000 has on its inner surface 1000b, which is in contact with the gas of the insulating gas-filled cavity 9002, and in contact with it, a functional stack 1001 according to the first aspect of the invention. The functional assembly 1001 is preferably deposited such that its outer surface, which is opposite the surface 1000b of the transparent glass sheet 1000, faces the interior (I) of the premises, for example a building, in which the glazing is to be used. In other words, the functional stack 1001 is placed on face 2 of the glazing starting from the exterior (E) side.

[0067] According to another embodiment, referring to FIG. 3, the glazing is a double glazing 3000 having a first glass sheet 1000 having an inner surface 1000a and an outer surface 1001b, a second transparent glass sheet 3001 having an inner surface and an outer surface, an insulating gas-filled cavity 3004, a spacer 3003, and a seal 3004.

[0068] The glass sheet 1000 has on its inner surface 1000a, which is in contact with the gas of the insulating gas-filled cavity 9004, a functional stack 1001 according to the first aspect of the invention. The functional assembly 1001 is preferably arranged so that its outer surface, which is opposite the surface 1000a of the transparent glass sheet 1000, faces towards the exterior (E) of the premises. In other words, the functional stack (1001) is arranged on face 3 of the glazing starting from the exterior (E) side.

[0069] Referring to Figure 4, there is also provided a laminated glazing 4000, comprising a first transparent substrate 1000 according to the first aspect of the invention, a lamination interlayer 4001, and a second transparent substrate 4002, whereby the first transparent substrate 1000 and the second transparent substrate 4002 are in adhesive contact with the lamination interlayer 4001, and the stack of thin layers 1001 of the first transparent substrate 1000 is in contact with the lamination interlayer 4001.

[0070] The laminate interlayer 4001 may consist of one or more layers of thermoplastic material, examples of which include polyurethane, polycarbonate, polyvinyl butyral (PVB), polymethyl methacrylate (PMMA), ethylene vinyl acetate (EA), or ionomer resins.

[0071] The laminate interlayer 4001 may be in the form of a multi-layer film, and it may also have specific functionality, such as acoustic properties or UV-resistant properties.

[0072] Typically, the laminate interlayer 4001 comprises at least one PVB layer. Its thickness is between 50 μm and 4 mm. Generally, it is less than 1 mm.

[0073] The deposition of thin layers on substrates, in particular on glass substrates, is a well-known process in industry. By way of example, the deposition of a stack of thin layers on a glass substrate is carried out by successive deposition of each thin layer of said stack by passing the glass substrate through a succession of deposition cells suitable for the deposition of a given thin layer.

[0074] The deposition cell may use deposition techniques such as magnetic field assisted sputtering, ion beam assisted deposition (IBAD), evaporation, chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PECVD), low pressure chemical vapor deposition (LPCVD), and the like.

[0075] A magnetic field assisted sputtering deposition method is particularly used. The deposition conditions of the layers are widely described in the literature, for example in WO 2012 / 093238 and WO 2017 / 00602.

[0076] According to a third aspect of the present invention, there is provided a method for producing a transparent substrate according to the first aspect of the present invention, wherein an absorbing layer of tungsten oxide is deposited by magnetron sputtering using a tungsten oxide target doped with a chemical element selected from group 1 of the chemical elements according to the IUPAC nomenclature.

[0077] The tungsten oxide target may in particular contain one or more doping elements in proportions as described for the doped tungsten oxide layer in some embodiments of the first aspect of the present invention.

[0078] An absorbing layer of tungsten oxide may be deposited by sputtering using the aforementioned targets in a deposition atmosphere consisting of 60-100% argon and 0-40% dioxygen, preferably 70-85% argon and 15-30% dioxygen.

[0079] The absorbing tungsten oxide layer may be deposited under a pressure of 1 to 15 mTorr (0.13332 to 1.9998 Pa), preferably 3 to 10 mTorr (0.39996 to 1.3332 Pa).

[0080] Preferably, the deposition may be carried out at low temperatures, ie below 100°C, in particular at temperatures between 20°C and 60°C, relative to the substrate.

[0081] The deposition can also be carried out at high temperatures, in particular at temperatures between 100°C and 400°C.

[0082] According to a particular embodiment, the substrate 1000 may be subjected to an annealing heat treatment after the deposition of the stack 1001. 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 minutes and 30 minutes, in particular between 5 minutes and 20 minutes, or even between 5 minutes and 10 minutes.

[0083] All the described embodiments, whether relating to the first or second aspect of the invention, can be combined with one another without modification or specific adaptation. If technical incompatibilities appear when implementing one of these combinations, it is within the scope of those skilled in the art to solve them according to their knowledge and without undue effort, in particular by carrying out a research program. EXAMPLES

[0084] The features and advantages of the present invention are illustrated by the non-limiting examples described below.

[0085] Twenty-three examples E1 to E23 according to the invention are listed in Tables 1, 2, 3 and 4, which give the composition of the various layers and their thicknesses in nanometers. The numbers in the first column correspond to the reference numbers of the figures.

[0086] The layer, designated CWO, is cesium-doped tungsten oxide, with the molar ratio of cesium to tungsten being about 0.05-0.06.

[0087] [Table 1]

[0088] [Table 2]

[0089] [Table 3]

[0090] [Table 4]

[0091] Three comparative examples, CE1 to CE3, are listed in Table 5, which shows the composition of the various layers and their thicknesses expressed in nanometers.

[0092] [Table 5]

[0093] The first dielectric module 1002 and the second dielectric module 1004 of the embodiments E1, E2, E13 and E19 only have silicon nitride based layers of different thicknesses.

[0094] The first dielectric module 1002 and / or the second dielectric module 1004 of the embodiments E3 to E6, E14 to E15, and E21 have layers of niobium nitride and / or mixed nickel-chromium nitride in addition to the silicon nitride based layers.

[0095] The first dielectric module 1002 and / or the second dielectric module 1004 of the embodiments E8-E12 have layers of niobium nitride and / or mixed nickel-chromium nitride in addition to the silicon nitride based layers. The mixed silicon nitride-zirconium nitride, SiZrN17, contains 17 atomic percent (17 mol%) zirconium, and the mixed silicon nitride-zirconium nitride, SiZrN27, contains 27 atomic percent (27 mol%) zirconium.

[0096] The first dielectric module 1002 and / or the second dielectric module 1004 of the embodiments E16 to E18 and E22 comprise, in addition to the silicon nitride based layer, a titanium nitride layer.

[0097] Comparative Example CE1 corresponds to Examples E1 to E12, Comparative Example CE2 corresponds to Examples E13 to E18, and Comparative Example CE3 corresponds to Examples E19 to E23.

[0098] The stacks of thin layers of Examples E1 to E23 and Comparative Examples CE1 to CE3 were deposited by magnetic field assisted cathode sputtering (magnetron method), the properties of which are widely described in the literature, for example in WO 2012 / 093238 and WO 2017 / 00602. The substrate 1000 is a soda-lime-silica inorganic glass with a thickness of 4 mm. After deposition, the substrate was subjected to a heat treatment at 650° C. for 10 minutes in air.

[0099] The properties of the targets used and the deposition conditions for Examples E1-E23 and Comparative Examples CE1-CE3 are summarized in Table 6.

[0100] [Table 6]

[0101] The solar factor g, selectivity s, light transmittance TL, light reflectance Rint on the inner surface, and light reflectance Rext on the outer surface, as well as color in transmission on the inner and outer surfaces, were measured for each of the substrates of Examples E1-E17 and Comparative Examples CE1-CE4 incorporated into a single glazing.

[0102] The term "color" used to describe the transparent substrate provided with the stack is L according to standard ISO 11664. * a * b * It is understood to mean a color defined in the CIE 1976 color space, which is measured in accordance with said standard.

[0103] The light transmittance in the visible spectrum TL, the solar factor g, the selectivity s, as well as the internal reflectance Rint and the external reflectance Rext in the visible spectrum are defined, measured and calculated in accordance with standards EN 410, ISO 9050 and / or ISO 10292.

[0104] The thermal transmittance Ug is defined, measured and calculated in accordance with the EN 673 standard.

[0105] The measured values ​​of solar factor, selectivity, light transmittance, internal and external reflectance, and emissivity are summarized in Table 7. 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 * The measured values ​​of Rint are summarized in Table 8.

[0106] [Table 7]

[0107] [Table 8]

[0108] Table 7 shows that the emissivity levels of the Examples are lower than, or otherwise comparable to, those of the Comparative Examples.

[0109] Values ​​of light transmission TL and solar factor g are shown for Examples E1-E12 (filled circles), E13-E18 (filled squares), and E19-E22 (filled triangles), and respective Comparative Examples CE1 (open circles), CE2 (open squares), and CE3 (open triangles) in Figure 5. The graph also shows selectivity thresholds s=0.8, s=1.0, and s=1.2 as a viewing angle guide.

[0110] 5 shows that for comparable light transmittance, the examples have higher selectivity values ​​than their respective comparative examples. The selectivity improvement can be as much as 0.3 or even 0.4 points.

[0111] External and internal reflectance values ​​are shown in FIG. 6 for Examples E1-E12 (filled circles), E13-E18 (filled squares), and E19-E22 (filled triangles), and for respective Comparative Examples CE1 (open circles), CE2 (open squares), and CE3 (open triangles).

[0112] 6 shows that the examples according to the invention have, for comparable light transmission values, reflection levels on the inner and outer faces that are smaller than or otherwise comparable to those of the comparative examples. In other words, the invention also makes it possible to reduce the reflection of light, especially on the inner faces, while maintaining the same level of light transmission.

[0113] Color parameter a * , b * The values ​​of the color parameter a in transmission are shown in FIG. 7 for Examples E1 to E22 (shown in black) and Comparative Examples CE1 to CE3 (shown in white). * T,b * T is represented by a circle, and the parameter a in the reflection on the external surface * Rext,b * Rext is expressed as a triangle, and the parameter a in the reflection on the internal surface * Rint,b * Rint is represented as a square.

[0114] In transmission, the examples according to the invention have a lower color parameter b * has.

[0115] In the external surface reflection, the examples according to the present invention have a lower color parameter b than the comparative example. * Has Rext.

[0116] In the internal surface reflection, the examples according to the present invention have a lower color parameter a than the comparative example. * Rint and b * Has Rint.

[0117] The stacks 1001 of Examples E1, E2, E3, E9, and E11, and Comparative Example CE1, are also used to form laminated glazings, designated VFE1, VFE2, VFE3, VFE9, VFE11, and VFCE1, respectively.

[0118] A functional coating 1001 was deposited under the same conditions as above on a sheet 1000 of 4 mm thick soda-lime-silica mineral glass. Immediately after deposition, the functional coating was subjected to a heat treatment at 650° C. for 10 minutes.

[0119] Once deposition and heat treatment are complete, each of the glass sheets 1000 having the functional coating 1001 is laminated with a laminating interlayer 2001 of 0.38 mm thick PVB, and a second glass sheet 2002 of 4 mm thick soda-lime-silica mineral glass to form the laminated glazing as shown in FIG.

[0120] The solar factor g, selectivity s, light transmittance Tl, light reflectance Rint on the inner surface and Rext on the outer surface, and color in transmission on the inner and outer surfaces were measured for each substrate of Examples VFE1, VFE2, VFE3, VFE9, VFE11, and Comparative Example VFCE1 incorporated into a laminated glazing.

[0121] The expression "colour", used to describe the laminated glazing provided with the stack, refers in particular to the colour of the glazing according to standard ISO 11664 with D65 illuminance and a viewing angle of 2° or 10° for the reference observer. * a * b * It is understood to mean a color defined in the CIE 1976 color space, which is measured in accordance with said standard.

[0122] The light transmittance in the visible spectrum TL, the solar factor g, the selectivity s, and the internal reflectance Rint and the external reflectance Rext in the visible spectrum are defined, measured and calculated in accordance with EN 410, ISO 9050, and / or ISO 10292.

[0123] The thermal conductivity Ug is defined, measured and calculated in accordance with standard EN 673.

[0124] The measured values ​​of solar factor, selectivity, light transmittance, internal reflectance, external reflectance, and emissivity are summarized in Table 9. 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 * The measured values ​​of Rint are summarized in Table 10.

[0125] [Table 9]

[0126] [Table 10]

[0127] Table 9 shows that the emissivity levels of the Examples are lower than, and otherwise comparable to, those of the Comparative Examples.

[0128] Values ​​of light transmission TL and solar factor g are shown for Examples VFE1, VFE2, VFE3, VFE9, VFE11 (filled circles) and Comparative Example VFCE1 (open circles) in Figure 8. The graph also shows selectivity thresholds s=1.0 and s=1.2 as a viewing angle guide.

[0129] 8 shows that for comparable light transmittance, the examples have higher selectivity values ​​than their respective comparative examples. The selectivity improvement can be as much as 0.2 percentage points.

[0130] External and internal reflectance values ​​are shown in FIG. 9 for VFE1, VFE2, VFE3, VFE9, VFE11 (filled circles) and the comparative example VFCE1 (open circles).

[0131] 9 shows that the examples according to the invention have, for comparable light transmission values, reflection levels on the inner and outer surfaces that are less than or otherwise comparable to those of the comparative examples. In other words, the invention also makes it possible to reduce light reflection, especially on the inner surfaces, while maintaining the same level of light transmission.

[0132] Color parameter a * , b * The values ​​of the color parameter a in transmission are shown in FIG. 10 for the examples VFE1, VFE2, VFE3, VFE9, and VFE11 (black circles) and the comparative example VFCE1 (white circles). * T, b * T is represented by a circle, and the parameter a in the reflection on the external surface * Rext, b * Rext is expressed as a triangle, and the parameter a for reflection on the internal surface is * Rint, b * Rint is represented as a square.

[0133] In transmission, the examples according to the invention have a lower color parameter b * has.

[0134] In the external surface reflection, the examples according to the present invention have a lower color parameter b than the comparative example. * Has Rext.

[0135] In the internal surface reflection, the examples according to the present invention have a lower color parameter a than the comparative example. * Rint and b * Has Rint.

Claims

1. A transparent substrate (1000) having on one of its main surfaces a thin layer stack (1001), said layer stack (1001) comprising, starting from said substrate (1000), the following layers: a first dielectric module (1002) of one or more thin layers; - an absorbent layer of tungsten oxide (1003); a second dielectric module (1004) of one or more thin layers; wherein said tungsten oxide comprises at least one doping element selected from the chemical elements of Group 1 according to the IUPAC nomenclature.

2. 2. The substrate (1000) of claim 1, wherein the absorbing layer (1003) of tungsten oxide comprises the doping element or elements in a proportion such that the molar ratio of the element to tungsten or the sum of the molar ratios of each element to tungsten is between 0.01 and 1, preferably between 0.01 and 0.6, or even between 0.02 and 0.

3.

3. 3. The substrate (1000) of claim 1 or 2, wherein the absorbing layer (1003) of tungsten oxide comprises at least one doping element selected from hydrogen, lithium, sodium, potassium, and cesium.

4. 4. The substrate (1000) of claim 3, wherein said absorbing layer (1003) of tungsten oxide comprises cesium as doping element, the molar ratio of cesium to tungsten being between 0.01 and 1, preferably between 0.05 and 0.

4.

5. Substrate (1000) according to claim 1 or 2, wherein the thickness of said absorbing layer (1003) of tungsten oxide is between 6 and 450 nm, in particular between 20 and 250 nm, preferably between 40 and 200 nm.

6. The substrate (1000) according to claim 1 or 2, wherein the first dielectric module (1002) and / or the second dielectric module (1004) consist of one or more layers based on nitride.

7. 7. The substrate (1000) of claim 6, wherein the nitride-based layer or layers of the first dielectric module (1002) and / or the second dielectric module (1004) are selected from aluminum nitride, silicon nitride, titanium nitride, niobium nitride, silicon zirconium nitride, silicon nitride doped with aluminum, zirconium, and / or boron.

8. Single or double glazing comprising a transparent substrate according to claim 1 or 2.

9. 1. A laminated glass (4000) comprising a first transparent substrate (1000) according to claim 1 or 2, a lamination interlayer (4001), and a second transparent substrate (4002), wherein the first transparent substrate (1000) and the second transparent substrate (4002) are in adhesive contact with the lamination interlayer (4001), and the thin layer stack (1001) of the first transparent substrate (1000) is in contact with the lamination interlayer (4001).

10. 3. A method for manufacturing a transparent substrate (1000) according to claim 1 or 2, wherein the absorbing layer (1003) of tungsten oxide is deposited by magnetron sputtering using a tungsten oxide target doped with a chemical element selected from the chemical elements of group 1 according to the IUPAC nomenclature.

11. A method according to claim 10, wherein the absorbing layer (1003) of tungsten oxide is deposited at a substrate temperature below 100°C, preferably between 20 and 60°C.

12. 11. A method according to claim 10, wherein said absorbing layer (1003) based on tungsten oxide is deposited in a deposition atmosphere composed of 60-100% argon and 0-40% dioxygen, preferably 70-85% argon and 15-30% dioxygen.

13. A method according to claim 10, wherein the absorbing layer (1003) of tungsten oxide is deposited at a pressure of 1 to 15 mTorr, preferably 3 to 10 mTorr.

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