Highly reflective solar-resistant glazing

Abstract

Transparent glass article for solar-protection glazing, comprising at least one glass substrate provided on at least one of its faces with a coating comprising the following succession of layers, starting from the surface of said substrate: - a layer comprising a nitride of at least one element chosen from Si, Al, said nitride optionally comprising Zr, with a physical thickness of between 1 and 25 nm, - an infrared-absorbing layer, consisting of a material comprising niobium or a material comprising nickel and chromium, with a physical thickness of between 1 and 20 nm, - a layer whose optical thickness is between 60 and 100 nm, comprising a nitride of at least one element chosen from Si, Al, said nitride further comprising Zr, in contact with the infrared-absorbing layer, with a refractive index at 550 nm greater than 2.2 or a set of layers whose total optical thickness is between 60 and 100 nm,said assembly comprising or being constituted by a) a layer comprising a nitride of at least one element chosen from Si, Al, said nitride optionally comprising Zr, in contact with the infrared-absorbing layer and b) by a layer of a dielectric material with a refractive index at 550 nm greater than 2.2, with a physical thickness greater than or equal to 15 nm.,

Description

Title of the invention: Solar-resistant glazing with high external reflection

[0001] The invention relates to insulating glazing known as solar control glazing, provided with stacks of thin layers, at least one of which is absorbent, i.e. it acts on solar and / or thermal radiation essentially by absorbing at least part of the near (solar) or far (thermal) infrared radiation. The present invention relates more particularly to glazing with layer(s), in particular those intended mainly for the thermal insulation of buildings.

[0002] Such glazings provided with stacks of thin layers act on the incident solar radiation by absorbing said radiation and / or by reflecting this radiation.

[0003] They are grouped under the name of solar control glazing. They are marketed and used mainly to ensure protection of the home from solar radiation and to prevent overheating.

[0004] By antisolar, we mean in the sense of the present invention the ability of the glazing to limit the energy flow, in particular the solar infrared radiation (1RS) passing through it from the outside to the inside of the dwelling or passenger compartment.

[0005] To fulfill the anti-solar function, such glazing advantageously comprises at least one absorbent layer, that is to say a layer absorbing part of the solar radiation and in particular solar infrared.

[0006] To measure the solar control properties of glazing, the solar factor noted FS or g is used in the field.

[0007] In a known manner, the solar factor g is equal to the ratio of the energy passing through the glazing (i.e. entering the room) and the incident solar energy. More particularly, it corresponds to the sum of the flux transmitted directly through the glazing and the flux absorbed by the glazing (including any stacks of layers present on one of its surfaces) and re-emitted towards the interior (the room). Currently, we are looking for glazings having a factor g as low as possible and at most equal to 50% (0.5).

[0008] Another important factor taken into account is the light transmission TL, which describes the percentage of visible light (between 380 and 780 nm) that passes through the glazing. TL values ​​can, however, vary greatly from one solar-resistant glazing to another depending on the level of sunshine in the country concerned, but also on the requirements of architects and other project managers. Typically, it can be estimated that the required light transmission can vary between 20 and 80%, depending on the requirements.

[0009] The most efficient stacks currently marketed to arrive to such performances incorporate at least one metallic layer of the silver type functioning essentially on the mode of reflection of a major part of the incident IR (infrared) radiation. These stacks can be used mainly as low-emissivity (or low-e in English) glazing or as solar-protection glazing. These layers are however very sensitive to humidity and oxidation. They are therefore exclusively used in double glazing, on face 2 or 3 of the latter, to be protected from humidity. For applications in the building or automobile fields, it is not possible to deposit such layers on single glazing. The stacks according to the present invention do not comprise such silver-based layers, or even gold or platinum-based layers, or only in very negligible quantities, in particular in the form of unavoidable impurities.

[0010] Stacks with low emissive or antisolar properties are also known but based on absorbent layers made of transparent conductive oxides (TCO) such as mixed oxides of tin and indium, such as for example the stacks described in publication US2009320824. However, to obtain glazings whose solar factor is less than 50%, it is necessary to deposit layer thicknesses of at least 100 nm. The deposition of such layers by magnetron-assisted sputtering techniques is therefore long and expensive. Advantageously, the stacks according to the present invention do not comprise such layers.

[0011] Other stacks with an anti-solar function have also been disclosed in the field, comprising absorbent layers of the metallic Nb or nitrided niobium NbN type, as described for example in application WO01 / 21540 or in application WO2009 / 112759. Within such niobium-based layers, and in particular nitrided niobium-based layers, the solar radiation is this time mainly absorbed non-selectively by the absorbent layer, that is to say that the IR radiation (that is to say whose wavelength is between approximately 780 nm and 2500 nm) and the visible radiation (whose wavelength is between approximately 380 and 780 nm) are absorbed without distinction by the active layer. As indicated in these publications, the use of niobium-based layers does not allow to achieve high external reflection (greater than 25%) for a light transmission greater than 35%.

[0012] An essential aspect to be taken into account is the exterior aesthetics of the building, which must be highly reflective and neutral or blue in color. According to another aspect of the present invention, the aim is to minimize reflection this time on the interior side of the building, for the reasons of comfort described below.

[0013] Also, an essential factor lies in the visual comfort of the occupants of the building or the interior equipped with the glazing. In particular, the vision through the glazing must be as clear as possible and the perceived color must be pleasant.

[0014] A light transmission of the order of 50% is therefore preferable, in order to guarantee good illumination of the interior of the building without excessive heating thereof.

[0015] We also distinguish, in this respect: - the external light reflection RLext, i.e. the light reflection measured on the face of the glazing exposed to the outside of the building or passenger compartment, and - the interior light reflection RLint, i.e. the light reflection measured on the face of the glazing facing inwards.

[0016] Generally speaking, all the luminous characteristics presented in the present description, in particular, the luminous transmission TL and the luminous reflections Rl, as well as the factor g, are obtained according to the principles and methods described in the standard NF EN 410 (2011) relating to the determination of the luminous and energy characteristics of glazing used in glass for construction.

[0017] In a glazing according to the invention, the so-called solar control stack can be arranged on the face of the glazing facing the interior of the building or the passenger compartment that it equips and in particular on face 2 of a single glazing, the faces being conventionally numbered from the outside to the inside.

[0018] In other words, the interior light reflection RLintest is measured on the face provided with the stack of layers (also called the layer side) while the exterior light reflection RLextest is measured on the bare face of the glazing (also called the glass side).

[0019] For the good comfort of the occupants of the building or the passenger compartment, it is first of all necessary that the internal reflection RLint be minimized, in particular less than 20%, so as to avoid a “mirror” effect of the glazing, that is to say a reflected image of the interior of the building to the detriment of the external view, in particular in oblique vision (that is to say with a non-zero angle relative to the normal to the glazing).

[0020] For the purposes of the present invention, we are therefore looking for glazings whose difference ARl = RLext - RLint is close to or greater than 6%.

[0021] Ideally, a screening effect is sought this time from the inside of the building, by observers from the outside. Such a property this time requires a sufficiently high external reflection, for example of the order of 30%, while nevertheless remaining significantly lower than the light transmission, for example at least 10%.

[0022] However, with such a level of external reflection (exterior side), the colorimetric aspect becomes critical for the general aesthetics of the building. It is sought in particular that such glazing has a neutral or slightly bluish coloring.

[0023] To obtain such a property, it is necessary that the values ​​of a* and b*, and in particular of b*, in the L system, a*, b* (typically under a viewing angle of 2° and under illuminant D65), or precisely adjusted. Values ​​of a* and b* sought are notably less than 0, as indicated in the rest of the description.

[0024] Not only do glazings comprising a single niobium-based absorbent layer, as described in application WO01 / 21540, have suitable colorimetry (negative a* and b*) but external reflection levels are too low (less than 20%). In addition, most of them have strong internal reflection and weak external reflection.

[0025] The present invention aims to meet the objectives described above and relates to glass articles having the majority and most often all of the following criteria: - a light transmission greater than or equal to 35%, preferably greater than 40%, and for example less than 70%, advantageously between 40 and 65%, - A solar factor substantially equal to or less than the light transmission value, in percentage, - an internal light reflection RLint (i.e. on the face of the substrate on which the stack of layers is deposited) less than or equal to 25%, preferably less than 20%, - a light reflection RLext (i.e. on the face of the substrate opposite which the stack of layers is deposited) greater than RLint and in particular greater than or equal to 25%, preferably greater than or equal to 30%, - negative external reflection parameters a* and b* in the colorimetric system L, a*, b* and in particular a parameter a*ext between 0 (excluded) and -3.5 and a parameter b*ext less than 0 and preferably less than -5, - preferably a difference between external reflection and internal reflection (ARl = RLext - RLint) of at least 6%, or even at least 7% or even at least 10%.

[0026] According to the invention, the parameters L, a* and b* are measured according to the CIE LAB criteria, under the illuminant D65, 2°.

[0027] By stack side, as indicated above, is meant the face of the glazing on which the stack is deposited. By glass side is meant the face of the glazing opposite that on which the stack is deposited, in principle not covered. For the purposes of the present invention, the terms "external face" (or "external") and "internal face" or ("internal") refer to the position of the glazing when it is fitted to the building or vehicle for which it is intended.

[0028] Furthermore, the glass articles and glazings according to the invention have solar control properties in accordance with those required in the field, in particular a factor solar g close and preferably less than 50%, or even less than 45% or even less than 40% in certain configurations.

[0029] More specifically, the present invention relates to a transparent glass article for anti-solar glazing, comprising at least one glass substrate provided on at least one of its faces with a coating consisting of a stack of layers, said stack comprising the following succession of layers, starting from the surface of said substrate: - a first layer comprising a nitride of at least one element chosen from Si, Al, said nitride optionally comprising Zr, with a physical thickness of between 1 and 25 nm, preferably between 5 and 20 nm,

[0030] - a second infrared-absorbing layer, consisting of a material comprising niobium or by a material comprising nickel and chromium, with a physical thickness of between 1 and 20 nm, preferably between 5 and 15 nm,

[0031] - a third layer whose optical thickness is between 60 and 100 nm, preferably between 65 and 95 nm, comprising a nitride of at least one element chosen from Si, Al, said nitride further comprising Zr, in contact with the infrared-absorbing layer, with a refractive index at 550 nm greater than 2.2 or a set of third layers whose total optical thickness is between 60 and 100 nm, preferably between 65 and 95 nm, said set comprising or preferably consisting of a) a layer comprising a nitride of at least one element chosen from Si, Al, said nitride optionally comprising Zr, in contact with the infrared-absorbing layer and b) a layer of a dielectric material with a refractive index at 550 nm greater than 2.2, with a physical thickness greater than or equal to 15 nm, preferably with a physical thickness greater than or equal to 20 nm,

[0032] - preferably a layer of a dielectric material with a refractive index of 550 nm less than 1.6, with a physical thickness between 1 and 25 nm, preferably between 5 and 20 nm,

[0033] - optionally a protective layer of a titanium oxide, of an oxide of zirconium or a titanium and zirconium oxide, with a physical thickness of between 1 and 5 nm, preferably between 1 and 3 nm.

[0034] According to particular and preferred embodiments of the present invention, which may be combined with each other where appropriate: - The stack only includes one IR absorbing layer. - The succession of layers comprises said layer of a dielectric material with a refractive index at 550 nm of less than 1.6, - Said layer of nitride with a refractive index at 550 nm greater than 2.2 or said layer of a dielectric material with a refractive index at 550 nm greater than 2.2 has a physical thickness preferably at least 1.5 times greater than said layer of a dielectric material with a refractive index at 550 nm less than 1.6. Said layer of a dielectric material with a refractive index at 550 nm greater than 2.2, with a physical thickness greater than 15 nm and the layer of a dielectric material with a refractive index at 550 nm less than 1.6 of said set of layers have a total cumulative physical thickness of between 25 and 50 nm, preferably between 25 and 35 nm. The layers comprising a nitride of at least one element chosen from Si, Al, and optionally comprising Zr, are in contact with the absorbent layer. The first layer of the stack comprising a nitride of at least one element chosen from Si, Al and optionally comprising Zr is in contact with the surface of the substrate and preferably is in contact with the absorbent layer. The first layer of the stack comprising a nitride of at least one element chosen from Si, Al and optionally comprising Zr is a silicon nitride or a silicon and aluminum nitride. Preferably in the layers according to the invention comprising silicon nitride or silicon and aluminum nitride, the silicon nitride preferably represents at least 50% of the weight of said layers, based on a Si3N4 formulation, and preferably more than 80% or even more than 90% by weight of said layers, based on the Si3N4 formulation.More preferably, said layers are based on silicon nitride, but may also comprise another metal such as aluminum. For example, aluminum is used in a well-known manner, in proportions of up to 10 atomic% or more, in silicon targets used for the deposition by cathode sputtering assisted by a magnetic field (magnetron) of layers containing silicon, in particular layers based on silicon nitride. The dielectric material with a refractive index at 550 nm greater than 2.2 in said set of layers comprises, preferably for more than 80% of its weight, an oxide of at least one element chosen from titanium, niobium, zirconium or their mixture, in particular comprises titanium oxide, niobium oxide, zirconium oxide, or a silicon and zirconium nitride or a silicon, aluminum and zirconium nitride. The dielectric material with a refractive index at 550 nm of less than 1.6 comprises silicon oxide or a silicon oxynitride, preferably a silicon oxide. Preferably, said material comprises more than 80% by weight of said oxides, and preferably consists of said oxides. The material constituting the absorbent layer is chosen from a material comprising niobium or niobium nitride, preferably niobium nitride. Preferably said material comprises more than 80% by weight of niobium or niobium nitride, and preferably consists of niobium or niobium nitride. - The material constituting the absorbent layer is chosen from niobium or an alloy of niobium with at least one other metal such as Zr or Ti, niobium representing at least 50% of the metal atoms present in said material, preferably representing at least 80% of the metal atoms present in said material. - The material constituting the absorbent layer comprises a niobium nitride or a nitride of niobium and at least one other metal such as Zr or Ti, the niobium representing at least 50% of the metal atoms present in said material, preferably representing at least 80% of the metal atoms present in said material. - The material constituting the absorbent layer comprises a nickel and chromium alloy or a nitride of a nickel and chromium alloy, an alloy in which the Ni / Cr atomic ratio varies between 2 and 9, preferably between 3 and 5. - The third layer comprising a nitride of at least one element chosen from Si, Al, and comprising Zr, with a refractive index at 550 nm greater than 2.2 and a silicon nitride or a silicon and aluminum nitride in which the Si / Zr ratio is between 1.5 and 6.0, preferably is between 2.0 and 5.5, or even is between 3.5 and 5.0. - The stack is only made up of the layers described above. - The stack comprises or is made up of the succession of the following layers, each layer being in direct contact with the next, starting from the surface of said substrate:

[0035] SiN / CA / SiN / TiO / preferably SiO / optionally TiO, ZrO or TiZrO

[0036] in which SiN denotes layers comprising silicon nitride, CA denotes the absorbing layer, in particular a layer of niobium or niobium nitride, SiO denotes a layer comprising silicon oxide, TiO denotes a layer comprising a titanium oxide, ZrO denotes a layer comprising a zirconium oxide and TiZrO denotes a layer comprising a titanium and zirconium oxide. - The stack comprises or is made up of the succession of the following layers, each layer being in direct contact with the next, starting from the surface of said substrate:

[0037] SiN / CA / SiN / NbO / preferably SiO / optionally TiO, ZrO or TiZrO,

[0038] in which SiN denotes layers comprising silicon nitride, CA denotes the absorbing layer, in particular a layer of niobium or niobium nitride, SiO denotes a layer comprising silicon oxide, NbO denotes a layer comprising niobium oxide, TiO denotes a layer comprising a titanium oxide, ZrO denotes a layer comprising a zirconium oxide and TiZrO denotes a layer comprising a titanium and zirconium oxide. - The stack comprises or preferably consists of the succession of the following layers, each layer being in direct contact with the next and from the surface of said substrate:

[0039] SiN / CA / SiN / SiZrN / preferably SiO / optionally TiO, ZrO or TiZrO

[0040] in which SiN denotes layers comprising silicon nitride, CA denotes the absorbing layer, in particular a layer of niobium or niobium nitride, SiO denotes a layer comprising silicon oxide, SiZrN denotes a layer comprising silicon and zirconium nitride, TiO denotes a layer comprising titanium oxide, ZrO denotes a layer comprising zirconium oxide and TiZrO denotes a layer comprising titanium and zirconium oxide. - The stack comprises or preferably consists of the succession of the following layers, each layer being in direct contact with the next and from the surface of said substrate:

[0041] SiN / CA / SiZrN / preferably SiO / optionally TiO, ZrO or TiZrO

[0042] in which SiN denotes layers comprising silicon nitride, CA denotes the absorbing layer, in particular a layer of niobium or niobium nitride, SiO denotes a layer comprising silicon oxide, SiZrN denotes a layer comprising silicon and zirconium nitride, TiO denotes a layer comprising titanium oxide, ZrO denotes a layer comprising zirconium oxide and TiZrO denotes a layer comprising titanium and zirconium oxide. - The stack does not include layers based on Ag, Au, Pt, Cu, Ni or stainless steel. - The item is thermally hardened and / or curved. - The article has a light transmission greater than or equal to 35%, in particular greater than or equal to 40%. - The article has an internal light reflection RLint (i.e. on the face of the substrate on which the stack of layers is deposited) less than or equal to 20%. - The article exhibits a light reflection RLext (i.e. on the face of the substrate opposite to which the stack of layers is deposited) on greater than or equal to 25%, preferably greater than or equal to 30%. - The article presents a difference between external reflection and internal reflection (ARL = RLext - RLint) of at least 6%, or even at least 8% or even at least 10%. - The article has in internal reflection at least one parameter b*, and preferably parameters a* and b*, negative, in the colorimetric system L, a*, b* and under the illuminant D65 2°, in particular an a*ext parameter between 0 (0 excluded) and -3.5 and a b*ext parameter less than 0 and preferably less than -5. - The article is a solar-protective glazing comprising only a single glass substrate. - The article is a multiple glazing unit comprising several glass substrates. - The article is a laminated glazing comprising a set of at least two glass substrates bonded by a thermoplastic film, particularly polyvinyl butyral (PVB).

[0043] Throughout the description, unless otherwise indicated, thicknesses are physical (geometric) thicknesses.

[0044] The optical thickness of a layer is obtained conventionally by multiplying its physical thickness by the refractive index at 550 nm of the material which constitutes it. For example, the optical thickness of a layer of silicon oxide (with a refractive index at 550 nm equal to 1.45) whose physical thickness is 10 nm is equal to 10 x 1.45 = 14.5 nm.

[0045] By infrared absorbing layer is meant a layer consisting of a material that at least partially absorbs infrared, in particular infrared from solar radiation between 780 nm and 3000 nm. The term "IR absorbing" does not exclude, within the meaning of the present invention, the possibility that said layer may also reflect another portion thereof.

[0046] A dielectric material is, for example, a material whose massive form, free of impurities, has a high resistivity, in particular a resistivity greater than 1010 ohm.meters (Qm) at room temperature (25°C).

[0047] A layer comprising silicon nitride according to the invention may further comprise the elements aluminum and zirconium.

[0048] The absorbent layer according to the invention is selected in order to obtain a relatively high light transmission value of the substrate, allowing vision from the inside to the outside without discomfort, while retaining a notable effect of controlling thermal input.

[0049] Preferably, the absorbent layer according to the invention comprises niobium and in particular niobium nitride.

[0050] In the layers according to the invention comprising niobium nitride, the nitride of niobium NbN preferably represents at least 50% by weight of said layers, and preferably more than 80% or even more than 90% of said layers. In a niobium nitride according to the invention, the N / Nb ratio can vary for example between 0 and 1.2, preferably is of the order of 1, that is to say corresponds substantially to a stoichiometric formulation NbiNp According to a possible embodiment of the present invention, the layers comprising niobium nitride or niobium may also comprise another element, for example chosen from zirconium, titanium, in a minor quantity compared to the niobium.

[0051] The formulation of the layers can be obtained conventionally by XPS photoelectron spectrometry, according to techniques well known in the field of materials. According to a preferred embodiment of the invention, said layers are preferably made essentially of niobium nitride, or even are made of niobium nitride, apart from unavoidable impurities.

[0052] The layer comprising niobium nitride or niobium may further comprise a small amount of oxygen, for example such that the O / Nb atomic ratio is less than 0.2, preferably less than 0.1. According to a preferred embodiment, however, the layers comprising niobium nitride or niobium do not comprise oxygen other than in the form of unavoidable impurities.

[0053] In the layers according to the invention comprising silicon oxide, the silicon oxide preferably represents at least 50% of the weight of said layers, based on a SiO2 formulation, and preferably more than 80% or even more than 90% of said layers, based on the SiO2 formulation. More preferably, said layers consist essentially of silicon oxide, but may also comprise aluminum. Aluminum is used in a well-known manner, in proportions of up to 10 atomic% or even more based on the sum of the elements Si and Al, in silicon targets used for the deposition by cathode sputtering assisted by a magnetic field (magnetron) of layers containing silicon, in particular layers based on silicon oxide.

[0054] In the layers according to the invention comprising niobium oxide, the niobium oxide preferably represents at least 50% of the weight of said layers, based on an Nb2O5 formulation, and preferably more than 80% or even more than 90% of said layers, based on the Nb2O5 formulation. More preferably, said layers consist essentially of niobium oxide.

[0055] In the layers according to the invention comprising titanium oxide, the titanium oxide preferably represents at least 50% of the weight of said layers, based on a TiO2 formulation, and preferably more than 80% or even more than 90% of said layers, based on the TiO2 formulation. More preferably, said layers consist essentially of titanium oxide.

[0056] In the layers according to the invention with a refractive index at 550 nm greater than 2.2 comprising silicon and zirconium nitride, the silicon and zirconium nitride preferably represents at least 70% of the weight of said layers, based on a SixZryN formulation, and preferably more than 80% or even more than 90% of the weight of said layers, based on said formulation.

[0057] In a layer comprising silicon and zirconium nitride according to the invention, the atomic ratio Si / Zr is between 1.5 and 6.0, and preferably is between 2.0 and 5.5, or even between 2.5 and 5.0. More preferably, said layers consist essentially of silicon and zirconium nitride, but may also comprise aluminum. Aluminum is used in a well-known manner, in proportions of up to 10 atomic%, based on the sum of the elements Si Zr and Al, or even more and preferably between 1 and 8 atomic%, based on the sum of the elements Si Zr and Al, in silicon targets used for the deposition of layers by cathode sputtering assisted by a magnetic field (magnetron).

[0058] The coatings according to the invention are conventionally deposited by deposition techniques of the type of vacuum sputtering assisted by a magnetic field of a cathode of the material or of a precursor of the material to be deposited, often called magnetron sputtering technique in the field. Such a technique is today conventionally used in particular when the coating to be deposited consists of a complex stack of successive layers with thicknesses of a few nanometers or a few tens of nanometers.

[0059] By the terms "underlayer" and "overlayer", reference is made in the present description to the respective position of said layers relative to the absorbent layer comprising niobium nitride in the stack, said stack being supported by the glass substrate taken as reference.

[0060] In particular, the underlayer is generally the layer in contact with the glass substrate and the overlayer is the outermost layer of the stack, facing away from the substrate.

[0061] The terms “above” or “below”, unless otherwise stated, are understood to refer to the surface of the substrate on which the stack is deposited.

[0062] If the application more particularly targeted by the invention is glazing for buildings, it is clear that other applications are conceivable, in particular in vehicle glazing (apart from the windshield where very high light transmission is required), such as side windows, car roofs, rear windows.

[0063] The invention and its advantages are described in more detail below by means of the non-limiting examples below, according to the invention and comparative examples. In all the examples and the description, the thicknesses given are physical.

[0064] All substrates are made of 6 mm thick clear glass of the Planiclear® type marketed by the company Saint-Gobain Glass France.

[0065] All layers are deposited in a known manner by magnetic field-assisted cathode sputtering (often called magnetron).

[0066] In a well-known manner, the different successive layers are deposited in the successive compartments of the cathode sputtering device, each compartment being provided with a specific metal target (for example in Si, or Nb) chosen for the deposition of a specific layer of the stack.

[0067] More precisely, the silicon nitride-based layers are deposited in a first compartment of the device from a metallic silicon target (doped with 8% by mass of aluminum), in a reactive atmosphere containing nitrogen (40% Ar and 60% N2). The silicon nitride layers, denoted Si3N4 for convenience, therefore also contain aluminum. These layers are subsequently designated according to the classic general formulation Si3N4, even if the deposited layer does not necessarily correspond to this assumed stoichiometry.

[0068] The silicon and zirconium nitride-based layers are deposited in a first compartment of the device from a silicon and zirconium target whose Si / Zr ratio is equal to 4.9 and further comprising 8% by mass of aluminum, in a reactive atmosphere containing nitrogen (40% Ar and 60% N2). The silicon and zirconium nitride layers, denoted SiZrN for convenience, therefore also contain aluminum.

[0069] The niobium nitride NbN layers are obtained by sputtering a metallic niobium target in an atmosphere comprising a mixture of nitrogen and argon, according to the conditions described in publication WO01 / 21540 or in publication WO2009 / 112759.

[0070] The silicon oxide layers are obtained by means of an aluminum-doped silicon target identical to that previously described according to a sputtering process in an atmosphere this time comprising oxygen and argon, according to techniques well known to those skilled in the art.

[0071] The titanium oxide layers are obtained by means of a titanium oxide target according to a sputtering process in an atmosphere this time comprising essentially argon and a little oxygen and, according to techniques well known to those skilled in the art. Examples 1 to 3:

[0072] In examples 1 to 3 according to the invention which follow, the glass substrate is successively covered, according to current magnetron-assisted sputtering deposition techniques, with a stack successively comprising a layer of niobium nitride surrounded by layers of silicon nitride with an index of refraction of 2.0, then layers of titanium oxide, with a refractive index of around 2.4 and silicon oxide, with a refractive index of around 1.45. Niobium nitride is substantially stoichiometric, based on an NbiNp formulation

[0073] A first stack according to example 1 is made up of the succession of the following layers:

[0074] Glass / Si3N4 (10 nm) / NbN (7 nm) / Si3N4 (11 nm) / TiO2 (21 nm) / SiO2 (8 nm)

[0075] The cumulative optical thickness of the two layers of Si3N4 and TiO2 is equal to 72 nm (11x2+21x2.4).

[0076] A second stack according to example 2 is made up of the succession of the following layers:

[0077] Glass / Si3N4 (10 nm) / NbN (7 nm) / Si3N4 (10 nm) / TiO2 (25 nm) / SiO2 (10 nm)

[0078] The cumulative optical thickness of the two layers of Si3N4 and TiO2 is equal to 80 nm.

[0079] A third stack according to example 3 is made up of the succession of the following layers:

[0080] Glass / Si3N4 (10 nm) / NbN (9 nm) / Si3N4 (9 nm) / TiO2 (21nm) / SiO2 (8 nm)

[0081] The cumulative optical thickness of the entire two layers of Si3N4 and TiO2 is equal to 68 nm. Example 4:

[0082] In this example, the glass substrate is successively covered, according to the current magnetron-assisted sputtering deposition techniques described above, with a stack successively comprising a layer of silicon nitride with a refractive index of 2.0, a layer of niobium nitride, a layer of silicon and zirconium nitride obtained from the SiZr metal target previously described and with a refractive index of the order of 2.3 and a layer of silicon oxide, with a refractive index of the order of 1.45. The niobium nitride is substantially stoichiometric, based on a formulation NbiNp

[0083] The fourth stack according to the invention is therefore made up of the succession of the following layers:

[0084] Glass / Si3N4 (10 nm) / NbN (7 nm) / SiZrN (30 nm) / SiO2(8 nm)

[0085] The optical thickness of the SiZrN layer is equal to 69 nm (30x2.3).

[0086] The values ​​of light transmission TL and external and internal light reflections Rext and Rint are measured in the range 380 nm to 780 nm according to the methods described in standard NF EN 410 (2011). The solar factor is measured according to this same standard, between 300 and 2500 nm.

[0087] The results obtained are grouped in Table 2 below, in percentages:

[0088] [Tables2] tl ^Lext Rbint RLext h* ü RLext FS (g) Ex.l 50 30 19 -2.2 -8.0 49 Ex.2 49 34 18 -2.8 -5.7 48 Ex. 3 44 31 18 -2.1 -7.9 42 Ex.4 50 30 21 -2.0 -9.3 51

[0089] The results reported in Table 2 above show that the glazings obtained from Examples 1 to 3 according to the invention have a solar factor less than or close to 50% (0.5), which guarantees good thermal insulation of the building or the passenger compartment.

[0090] It can be seen from Table 2 that the glazings according to the invention all have a blue color in external reflection.

[0091] Finally, it can also be seen that all the glazings according to the invention, unlike the comparative examples, have not only a reduced internal reflection but also a significantly increased AR difference between the external reflection and the internal reflection. Such a property ensures, as indicated previously, the visual comfort of the occupants of the building or the passenger compartment equipped with the glazing, in daytime vision as well as in night vision. Examples 5 and 6:

[0092] In example 5, according to another embodiment of the invention, the following stack is described:

[0093] Glass / Si3N4 (10 nm) / Nb (4nm) / Si3N4 (12 nm) / TiO2 (30nm) / SiO2 (8 nm)

[0094] The cumulative optical thickness of the entire two layers of Si3N4 and TiO2 is equal to 96 nm.

[0095] In example 6, according to another embodiment of the invention, the following stack is described:

[0096] Glass / Si3N4 (20 nm) / NiCr (5 nm) / Si3N4 (8 nm) / TiO2 (27nm) / SiO2 (8 nm)

[0097] The cumulative optical thickness of the entire two layers of Si3N4 and TiO2 is equal to 81 nm.

[0098] The results obtained are grouped in table 3 below, in percentages:

[0099] [Tables 3] tl ^Lext Rbint d RLext h* ü RLext FS (g) Ex. 5 48 37 16 -3.3 -3.6 48 Ex. 6 50 29 14 -2.9 -7.0 50

[0100] The results reported in Table 3 above show that the glazings obtained from examples 5 and 6 according to the invention have a solar factor less than or close to 50% (0.5), which guarantees good thermal insulation of the building or the passenger compartment.

[0101] It can be seen from Table 3 that the glazings according to the invention all have a blue color in external reflection.

[0102] Finally, it can also be seen that the glazings according to examples 5 and 6 according to the invention, unlike the comparative examples, exhibit not only reduced internal reflection but also a significantly increased AR difference between the external reflection and the internal reflection. Examples according to the prior art:

[0103] The properties of the stacks of the application WO 01 / 21540 cited above can be compared.

[0104] Example 4 of application WO01 / 21540 describes a succession of layers in the stack:

[0105] Glass / Si3N4 (lOnm) / Nb (12 nm) / Si3N4 (17 nm)

[0106] In the table on page 18 of this publication, for a light transmission of 32.3%, it is indicated that the light reflection RLext is 14.4% and the light reflection RLint is 25.3%.

[0107] The value of the internal reflection appears too high and higher than that of the external reflection, contrary to the objectives sought by the present invention, as described previously.

[0108] Similarly, example 6 of application WO01 / 21540 describes a succession of layers in the stack:

[0109] Glass / Si3N4 (lOnm) / NbN (10 nm) / Si3N4 (15 nm)

[0110] In the table on page 18 of this publication, the reported values ​​of RLext and RLint are respectively equal to 17.9% and 27.8%. As for the previous stack, it can be seen that the internal reflection is also much higher for this configuration and the external reflection much too low for the objective sought according to the present invention.

Claims

Claims

1. Transparent glass article for solar-protection glazing, comprising at least one glass substrate provided on at least one of its faces with a coating consisting of a stack of layers, said stack comprising the following succession of layers, starting from the surface of said substrate: - a layer comprising a nitride of at least one element chosen from Si, Al, said nitride optionally comprising Zr, with a physical thickness of between 1 and 25 nm, preferably between 5 and 20 nm, - an infrared-absorbing layer, consisting of a material comprising niobium or a material comprising nickel and chromium, with a physical thickness of between 1 and 20 nm, preferably between 5 and 15 nm, - a layer whose optical thickness is between 60 and 100 nm, preferably between 65 and 95 nm, comprising a nitride of at least one element chosen from Si, Al, said nitride further comprising Zr, in contact with the infrared-absorbing layer infrared,of refractive index at 550 nm greater than 2.2 or a set of layers whose total optical thickness is between 60 and 100 nm, preferably between 65 and 95 nm, said set comprising or consisting of a layer comprising a nitride of at least one element chosen from Si, Al, said nitride optionally comprising Zr, in contact with the infrared absorbing layer and by a layer of a dielectric material of refractive index at 550 nm greater than 2.2, of physical thickness greater than 15 nm, preferably of physical thickness greater than or equal to 20 nm, - preferably a layer of a dielectric material of refractive index at 550 nm less than 1.6, of physical thickness between 1 and 25 nm, preferably between 5 and 20 nm, - optionally a protective layer of a titanium oxide, a zirconium oxide or an oxide of titanium and zirconium, with a physical thickness between 1 and 5 nm, preferably between 1 and 3 nm,

2. llili. Glass article according to claim 1, in which the stack comprises only one IR-absorbing layer.

3. Glass article according to one of the preceding claims, in which the succession of layers comprises said layer of a dielectric material with a refractive index at 550 nm of less than 1.6, and in which said layer of a dielectric material with a refractive index at 550 nm greater than 2.2 has a physical thickness preferably at least 1.5 times greater than said layer of a dielectric material with a refractive index at 550 nm less than 1.

6.

4. Article according to one of the preceding claims, in which the layer of a dielectric material with a refractive index at 550 nm greater than 2.2, of thickness greater than 15 nm and the layer of a dielectric material with a refractive index at 550 nm less than 1.6 have a total cumulative physical thickness of between 25 and 50 nm, preferably between 25 and 35 nm.

5. Article according to one of the preceding claims in which the layers comprising a nitride of at least one element chosen from Si, Al, and optionally comprising Zr, are in contact with the absorbent layer.

6. Article according to one of the preceding claims wherein the dielectric material with a refractive index at 550 nm greater than 2.2 in said set of layers comprises an oxide of at least one element chosen from titanium, niobium, zirconium or a mixture thereof, in particular comprises titanium oxide, niobium oxide, zirconium oxide, or a silicon and zirconium nitride or a silicon, aluminum and zirconium nitride.

7. Article according to one of the preceding claims in which the dielectric material with a refractive index at 550 nm of less than 1.6 comprises silicon oxide or a silicon oxynitride, preferably a silicon oxide.

8. Article according to one of the preceding claims in which the material constituting the absorbent layer is chosen from a material comprising, and preferably consisting essentially of, niobium or niobium nitride, preferably niobium nitride.

9. Article according to one of the preceding claims in which the material constituting the absorbent layer is chosen from niobium or an alloy of niobium with at least one other metal, niobium representing at least 50% of the metal atoms present in said material, preferably representing at least 80% of the metal atoms present in said material.

10. Article according to one of claims 1 to 8 in which the material constituting the absorbent layer comprises a niobium nitride or a nitride of niobium and at least one other metal, the niobium representing at least 50% of the metal atoms present in said material, preferably representing at least 80% of the metal atoms present in said material.

11. Article according to one of claims 1 to 7 in which the material constituting the absorbent layer comprises an alloy of nickel and chromium or a nitride of an alloy of nickel and chromium, in which the atomic ratio Ni / Cr varies between 2 and 9, preferably between 3 and

12. J. Article according to one of the preceding claims in which the stack is constituted solely by the layers described in said claims.

13. Article according to one of the preceding claims, in which the stack comprises or is constituted by the succession of the following layers, each layer being in direct contact with the next, starting from the surface of said substrate: SiN / CA / SiN / TiO / preferably SiO / optionally TiO, ZrO or TiZrO in which SiN denotes layers comprising silicon nitride, CA denotes the absorbent layer, in particular a layer of niobium or niobium nitride, SiO denotes a layer comprising silicon oxide, TiO denotes a layer comprising a titanium oxide, ZrO denotes a layer comprising a zirconium oxide and TiZrO denotes a layer comprising a titanium and zirconium oxide.

14. Article according to one of claims 1 to 12, in which the stack comprises or is constituted by the succession of the following layers, each layer being in direct contact with the next, starting from the surface of said substrate: SiN / CA / SiN / NbO / preferably SiO / optionally TiO, ZrO or TiZrO, in which SiN denotes layers comprising silicon nitride, CA denotes the absorbing layer, in particular a layer of niobium or niobium nitride, SiO denotes a layer comprising silicon oxide, NbO denotes a layer comprising niobium oxide, TiO denotes a layer comprising a titanium oxide, ZrO denotes a layer comprising a zirconium oxide and TiZrO denotes a layer comprising a titanium and zirconium oxide.

15. An article according to any one of claims 1 to 12, wherein the stack comprises or preferably consists of the succession of the following layers, each layer being in direct contact with the next and from the surface of said substrate: SiN / Ca / SiN / SiZrN / preferably SiO / optionally TiO, ZrO or TiZrO in which SiN denotes layers comprising silicon nitride, CA denotes the absorbing layer, in particular a layer of niobium or niobium nitride, SiO denotes a layer comprising silicon oxide, SiZrN denotes a layer comprising silicon and zirconium nitride, TiO denotes a layer comprising titanium oxide, ZrO denotes a layer comprising zirconium oxide and TiZrO denotes a layer comprising titanium and zirconium oxide.

16. Article according to one of claims 1 to 12, in which the stack comprises or preferably consists of the succession of the following layers, each layer being in direct contact with the next and from the surface of said substrate: SiN / CA / SiZrN / preferably SiO / optionally TiO, ZrO or TiZrO in which SiN denotes layers comprising silicon nitride, CA denotes the absorbing layer, in particular a layer of niobium or niobium nitride, SiO denotes a layer comprising silicon oxide, SiZrN denotes a layer comprising silicon and zirconium nitride, TiO denotes a layer comprising titanium oxide, ZrO denotes a layer comprising zirconium oxide and TiZrO denotes a layer comprising titanium and zirconium oxide.

17. Article according to one of the preceding claims, characterized in that the stack does not comprise layers based on Ag, Au, Pt, Cu, Ni or stainless steel.