Solar-resistant glazing comprising a single functional layer of titanium nitride

Abstract

The present invention relates to a glass article comprising at least one glass substrate on which a stack of layers is deposited, said stack of layers comprising the succession of the following layers starting from the surface of said glass substrate: - a first layer comprising titanium nitride having a physical thickness of between 20 and 32 nm, said first layer being arranged directly in contact with said surface or above a dielectric sub-layer having a physical thickness of less than or equal to 15 nm, said sub-layer being arranged between said surface and said first layer and preferably directly in contact with them, - a second layer comprising silicon nitride, the cumulative physical thickness of the first layer and the second layer being between 70 and 80 nm, and said stack comprising a single layer comprising titanium nitride.The present invention also relates to building glazing, in particular solar-proof glazing, comprising a glass article as described above.

Description

Title of the invention: Solar-resistant glazing comprising a single functional layer of titanium nitride

[0001] The invention relates to glass articles for solar control glazing and said glazing, provided with stacks of thin layers of which at least one is "functional", that is to say that it acts on solar and / or thermal radiation essentially by reflection and / or absorption of near (solar) or far (thermal) infrared radiation. The present invention relates more particularly to glazing with layer(s), in particular those intended mainly for a solar protection function for buildings, often called anti-solar glazing.

[0002] The term "functional" or "active" layer, within the meaning of the present application, means the layer of the stack which gives the stack most of its thermal properties. Most often, the thin-film stacks equipping the glazing give it improved solar control properties essentially through the intrinsic properties of this active layer. For so-called anti-solar glazing, said layer acts on the flow of solar radiation passing through said glazing, as opposed to the other layers, generally made of dielectric material and essentially having the function of chemical or mechanical protection of said functional layer.

[0003] Such glazings provided with stacks of thin layers act on the incident solar radiation either essentially by the absorption of the incident radiation by the functional layer, or essentially by reflection by this same layer.

[0004] They are grouped under the name of solar control glazing. They are marketed and used mainly: - either to essentially ensure protection of the home from solar radiation and prevent overheating, such glazing being qualified in the anti-solar trade, - either essentially to ensure thermal insulation of the home and prevent heat loss, these glazings being qualified as insulating glazing.

[0005] 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 the passenger compartment; while maintaining a light transmission allowing vision at least from the inside to the outside of the building or the passenger compartment with which it is fitted.

[0006] Ideally, such glazings should also be aesthetically pleasing, i.e. they should have a colouring both in transmission and in reflection. as neutral as possible. Significantly more pronounced shades, for example blue or green, are also sometimes requested, but to satisfy very specific aesthetic criteria. These aesthetic criteria can, however, sometimes lead to situations that conflict with obtaining the best sunscreen properties sought.

[0007] Solar-proof glazings are known from the prior art, comprising one or more functional layers absorbing and / or reflecting solar radiation, each of these layers being surrounded by dielectric layers. However, these known glazings only partially meet the solar-proof properties sought according to the invention described below, but do not meet the desired aesthetic properties.

[0008] Thus, in document FR3068031, a glazing with solar-protection properties is described, comprising a functional layer based on titanium oxynitride surrounded by layers of dielectric materials. This stack makes it possible to give the glazing, in addition to the solar-protection properties, low-emissivity properties (i.e. far-infrared reflection properties). In this document, the dielectric layer placed below said functional layer has a high thickness, which results in an additional production cost for the stack linked to the deposition time of this layer. In addition, the glazing obtained has a rather low light transmission and exterior light reflection of the order of 27% and 21% respectively, and a significant mirror effect, characteristic of high interior light reflection.

[0009] Stacks comprising at least two functional layers based on titanium nitride (TiN) are also known. Document WO2018 / 129135 describes, for example, stacks based on two functional layers of titanium nitride. In this document, each of the titanium nitride layers is framed by dielectric layers, and in particular based on silicon nitride having a high thickness; thus creating a very thick stack of layers, which results in an additional production cost linked to the deposition time of each of the layers. Also, although some of the stacks described in this application provide a substantially neutral coloring in external reflection, the external reflection of said glazing is low, of the order of 10 to 18%.

[0010] Other embodiments are also known, in particular the Antelio clear® product marketed by the applicant company, anti-solar glazings highly reflective of visible light on the exterior side, obtained by hot spraying of a layer of metal oxides onto a clear glass substrate by the method known as CVD (chemical vapor deposition). However, such glazings have a strong reflection of visible light on the interior side (layer side) causing an undesirable mirror effect indoors, particularly at night.

[0011] Generally speaking, all the luminous characteristics presented in the present description, in particular the luminous transmission TL and the luminous reflection RL, are obtained according to the principles and methods described in the standard NF EN 410 (2011) relating to the determination of the luminous and solar characteristics of glazing used in glass for construction.

[0012] In the present invention, the applicant has sought to provide a glass article, in particular a glazing, provided with a stack of layers with anti-solar properties having a high light transmission, a high reflection on the side intended to be exposed towards the outside of the building (called external light reflection in the present description, that is to say on the face of the glazing not covered with the stack of thin layers acting on the solar radiation, on the glass substrate side); said stack must also give said glazing a favorable aesthetic appearance, and said glazing must be simple and inexpensive to manufacture, in particular with a minimum of layers and / or less thick layers.

[0013] By "favorable aesthetic appearance" is meant in the present invention that an attempt has been made to provide anti-solar glazing whose stack of layers gives said glazing: - a neutral color in transmission, - a color that is as neutral as possible in external reflection (glass side), in other words a color that can be slightly blue or slightly green / yellow, and - optionally a neutral color in internal reflection (layer side).

[0014] For the purposes of the present invention, the term “neutral” color means, in the international colorimetry system (L*, a*, b*), a* values ​​and b* values ​​close to zero, in particular values ​​between -5 and 5.

[0015] In addition to the anti-solar properties previously set out, in the field of construction in particular, in night vision, that is to say when the exterior brightness is lower than the interior brightness, the glazing may pose the disadvantage of presenting a mirror effect for an observer placed inside the building, if the interior reflection of the glazing is too significant and much greater than the exterior reflection. Such a mirror effect is undesirable because it prevents the observer placed inside the building from seeing the exterior of the building.

[0016] Thus, another objective of the present invention is to provide a glass article limiting the interior mirror effect, in particular thanks to a limited reflection on the interior side (face of the glazing on which the stack is deposited), and in particular a reflection on the interior side much lower than the exterior reflection.

[0017] The invention, in at least one of its embodiments, also aims to provide a glass article provided with a stack of layers having good durability from a chemical point of view (i.e. good resistance to corrosion, to abrasion, saline solutions etc.) and advantageously good mechanical durability, i.e. good resistance to heat treatments such as quenching or bending.

[0018] The problems described above could be solved according to the invention thanks to the development of glass articles having all or part of the following characteristics: - a light transmission “TL” greater than or equal to 35%, preferably greater than or equal to 40%, and more preferably between 40 and 55%, - an external light reflection “RLext” in the visible (glass substrate side, on the external face) greater than or equal to 26%, preferably greater than or equal to 28%, - a value of the colorimetric coordinate a*ext in external reflection between -5 and 0, preferably between -4 and -1 and a value of the colorimetric coordinate b*ext in external reflection between -5 and 5, preferably between -2 and 2, - values ​​of the colorimetric coordinates a*T and b*T in transmission between -5 and 3, preferably between -3 and 2, - preferably a value of the colorimetric coordinate a*int in internal reflection between -10 and 10, more preferably between -5 and 0, and a value of the colorimetric coordinate b*int in internal reflection less than 0, - preferably an internal light reflection “RLint” in the visible range (layer side, on the inner face) less than or equal to 8%, more preferably less than or equal to 4%, - preferably still an external light reflection “RLext” greater than the internal light reflection “RLint”, and more preferably a difference between the two light reflections RLext - RLint (also noted ARL in the rest of the description) greater than 20% or even greater than 25%.

[0019] According to the invention, the term “external light reflection” in the visible range means light reflected towards the external environment and the term “internal light reflection” in the visible range means light reflected towards the interior of a building or a vehicle. Thus, in the present application, a reflection on the external side (or called “external reflection”) corresponds to the reflection on the face of the glass article that is not covered (glass substrate side) and a reflection on the internal side (or called “internal reflection”) corresponds to the reflection on the face of the glass article on which the stack of layers is deposited. The terms “external face” (or “external”) and “internal face” or (“internal”) therefore refer to the position of the glass article or the glazing when it is fitted to the building or the vehicle that it is fitted to, within the meaning of the present application. invention. And, by "stack side" or "layer side", we mean the face of the glass article on which the stack is deposited. By "glass substrate side" or "glass side", we mean the face of the glass article opposite that on which the stack is deposited, in principle not covered.

[0020] The object of the present invention is therefore to propose a solar-proof glass article, in particular solar-proof glazing, making it possible to solve the technical problems described above.

[0021] To this end, the present invention relates firstly to a glass article comprising at least one glass substrate on which a stack of layers is deposited, said stack of layers comprising the succession of the following layers starting from the surface of said glass substrate: - a first layer comprising titanium nitride having a physical thickness of between 20 and 32 nm, said first layer being arranged directly in contact with said surface or above a dielectric sub-layer having a physical thickness of less than or equal to 15 nm, said sub-layer being arranged between said surface and said first layer and preferably directly in contact with them, - a second layer comprising silicon nitride, preferably said second layer is directly in contact with said first layer comprising titanium nitride, the cumulative physical thickness of the first layer and the second layer being between 70 and 80 nm, and said stack comprising a single layer comprising titanium nitride.

[0022] It was surprisingly found by the inventors that the combination of the characteristics of the stack of layers (as defined in the present invention) advantageously provided an appreciable and appreciated aesthetic effect, due to the neutral coloring conferred on the glass article on the glass side (external face), while maintaining privacy from the outside to the inside of the space closed by the glass article due to obtaining a high light transmission and a high external light reflection.

[0023] On the other hand, from the inside to the outside, the stack according to the invention advantageously makes it possible to maintain visual comfort and good visibility due to the obtaining, according to the invention, of low interior light reflection.

[0024] The glass substrate according to the invention is in particular made of soda-lime-silica glass, but it can also be of borosilicate or aluminosilicate type. Clear soda-lime-silica glasses are preferred. The thickness of the glass substrate can vary between 0.1 mm and 20 mm, in particular between 2 and 8 mm.

[0025] According to the invention, the stack of layers of the glass article comprises, from the surface of the glass substrate, a first layer comprising titanium nitride which has a physical thickness of between 20 and 32 nm, preferably between 20 and 28 nm, and more preferably between 20 and 25 nm. This thickness plays a determining role in the light transmission and, to a lesser extent, in the level of external light reflection as well as in the desired external reflection colors.

[0026] Said first layer comprising titanium nitride is arranged either directly in contact with the surface of the glass substrate, or above a dielectric sub-layer having a physical thickness less than or equal to 15 nm. This first layer is the only layer of the stack which comprises titanium nitride and advantageously the titanium nitride layer is the only functional layer of the stack of layers. In other words, this layer is preferably the only layer of the stack which can absorb and / or reflect all or part of the solar infrared radiation. Said layer comprising titanium nitride preferably comprises more than 80% or even more than 90% by weight of titanium nitride. Preferably, this layer consists essentially of titanium nitride.

[0027] The titanium nitride according to the invention is not necessarily stoichiometric (Ti / N atomic ratio of 1) but may also be over- or under-stoichiometric. According to an advantageous embodiment, the N / Ti ratio is between 1 and 1.2. Also, the titanium nitride according to the invention may comprise a minor quantity of oxygen, for example between 1 and 10 mol% of oxygen, in particular between 1 and 5 mol% of oxygen.

[0028] According to a particularly preferred embodiment, the titanium nitride layer according to the invention corresponds to the general formula TiNxOy, in which 1.00 < x < 1.20 and in which 0.01 < y < 0.10.

[0029] According to one of the alternatives of the invention, a dielectric sub-layer is arranged below the layer comprising titanium nitride and has a thickness less than or equal to 15 nm, preferably this thickness is between 5 and 10 nm. This thickness makes it possible to obtain a high external light reflection and a tint or coloration that is as neutral as possible in reflection from the side of the glass substrate. This sub-layer is preferably directly in contact with the surface of the glass substrate and the first layer comprising titanium nitride.

[0030] By dielectric layer is meant that said layer is made of a dielectric material. By "dielectric" or "dielectric material" is meant in particular any material known as such and in particular whose massive form and free of impurities has a resistivity initially greater than 1010 ohm-meters (Qm) at a temperature of 20°C. Such materials, once deposited in thin layers, may however comprise additional elements increasing significantly their electrical conductivity, useful in particular for improving the sputtering efficiency of the precursor material constituting the magnetron target.

[0031] The dielectric sub-layer thus comprises at least one dielectric material chosen from silicon nitride optionally doped with Al, Zr, B, aluminum nitride, tin oxide, a mixed oxide of zinc or tin SnyZnzOx, a silicon oxide, such as silicon dioxide, titanium oxide and silicon oxynitrides SiOxNy. Preferably, the dielectric sub-layer comprises silicon nitride, optionally doped with Al, Zr, B, preferably with Al, or silicon dioxide and more preferably the dielectric sub-layer comprises silicon dioxide, optionally doped with Al, Zr, B, preferably with Al.

[0032] This undercoat has the particular advantage of making the glass article resistant to heat treatments; the heat treatment being intended to mechanically reinforce the glass substrate by creating strong compressive stresses on its surface. Advantageously, the undercoat is deposited directly on the glass substrate and is in contact with it.

[0033] The second layer of the stack of the glass article according to the invention comprises silicon nitride, and the cumulative physical thickness of the first layer comprising titanium nitride and of said second layer is between 70 and 80 nm. The layer comprising silicon nitride thus has a physical thickness preferably between 35 and 50 nm, and more preferably between 45 and 50 nm.

[0034] Indeed, the inventors have found that the nature of the first layer and the second layer of the stack as well as a cumulative thickness of the first layer comprising titanium nitride and the second layer comprising silicon nitride specifically between 70 and 80 nm made it possible to obtain a glass article having a good compromise between external reflection and internal reflection; in other words a very high external reflection and a very low internal reflection, and a coloring (or tint) as neutral as possible in reflection on the side of the glass substrate.And in the particular case, where the stack includes a sub-layer also made of silicon nitride, the inventors noticed that it was the difference in thickness between the second layer comprising silicon nitride (thickness between 35 and 50 nm) and said sub-layer (thickness less than 15 nm) which made it possible to obtain a glass article presenting a good compromise between external reflection and internal reflection; in other words a very high external reflection and a very low internal reflection, and a coloring (or tint) as neutral as possible in reflection on the side of the glass substrate.

[0035] The second layer comprising silicon nitride and the optional sub-layer comprising silicon nitride, comprise mainly silicon and nitrogen as main constituents. In particular, silicon and nitrogen together represent more than 50%, more than 60% or even more than 70% or even more than 80% of the atoms present in a layer, or even more than 90% of the atoms present in a layer. Preferably, said layers comprising silicon nitride are essentially made up of silicon and nitrogen and optionally of at least one element chosen from aluminum, boron or zirconium, preferably aluminum, apart from unavoidable impurities. Said layers comprising silicon nitride are in principle free of oxygen apart from unavoidable impurities, for example they comprise less than 5 mol% of elemental oxygen, in particular less than 1 mol% of elemental oxygen.

[0036] Preferably, the second layer and the sub-layer described above have an N / Si ratio greater than 1.25 and are layers based on stoichiometric or substantially stoichiometric silicon nitride, preferably substantially stoichiometric. By "stoichiometric" is meant that the N / Si ratio is equal to 1.33 for these silicon-based nitride layers, corresponding to the Si3N4 compound. By "substantially stoichiometric" is meant, for example, that the value measured for this Si3N4 compound differs by less than 5% from this theoretical value.

[0037] Indeed, it should be noted that the layers comprising silicon nitride according to the invention are obtained by a magnetron-assisted cathode sputtering process from a metallic silicon target which may comprise a minor quantity of another element such as aluminium, most often around 8 atomic%, in a reactive atmosphere containing nitrogen. In such a case, the N / Si ratio may vary substantially from the theoretical value 1.33 (= 4 / 3) (corresponding to the defined compound Si3N4) taking into account the stoichiometries of the defined compounds AIN and Si3N4.For example, for a layer of silicon nitride comprising a little aluminum, obtained with the target described previously (8% aluminum), the N / Si ratio of the stoichiometric layer theoretically corresponds to a formulation: 92% (SiNt33) / 8% (AIN) or an N / Si ratio of 1.41 (based on a theoretical formula 0.92 SiN1>33 0.08 AIN, or a ratio: N / Si = [(0.92x1.33+0.08x1 ) / (0.92)] = 1.41).

[0038] The contents of the various elements present in the layers described above, and in particular the N / Ti and N / Si ratios, can be measured using any known technique. For example, energy-dispersive X-ray spectroscopy (EDS or EDXS) or the X-ray photoelectron spectrometry technique (XPS).

[0039] According to a preferred embodiment of the invention, the stack of layers further comprises a dielectric overlayer placed above the second layer comprising silicon nitride. Said dielectric overlayer has a physical thickness less than or equal to 15 nm and a refractive index measured at 550 nm less than or equal to 1.6. Preferably, the dielectric overlayer has a physical thickness of between 8 and 10 nm. And advantageously, the dielectric overlayer comprises silicon dioxide.

[0040] This dielectric overcoat has the advantage of making the glass article resistant to chemical attacks, in particular corrosion, abrasion, saline solutions, etc.

[0041] By the terms "underlayer" and "overlayer", reference is made in the present description to the respective position of said layers relative to the functional layer comprising titanium nitride, said stack being supported by the glass substrate taken as reference.

[0042] In particular, the underlayer is generally the layer closest to or directly in contact with the glass substrate and the overlayer is the outermost layer of the stack, facing away from the glass substrate.

[0043] The stack according to the invention may further incorporate between the first layer comprising titanium nitride and the second layer comprising silicon nitride, a metal layer, said metal layer comprising chromium, nickel, niobium or a mixture of at least two of these elements, said metal layer being optionally nitrided and / or optionally having a thickness less than or equal to 5 nm, in particular less than 4 nm. The particularly preferred metal layer comprises niobium, and is optionally and preferably nitrided. This additional metal layer makes it possible to increase the external reflection and / or to neutralize the colors on the external side.

[0044] Preferably, the stack of layers according to the invention does not comprise layers based on Ag, Au, Pt, Cu, or stainless steel.

[0045] Advantageously, each of the layers of the stack is in direct contact with the previous one.

[0046] In a first preferred embodiment of the invention, the stack comprises or is constituted by the succession of the following layers, starting from the surface of the glass substrate: - a first layer comprising titanium nitride having a physical thickness of between 20 and 25 nm, - a second layer comprising silicon nitride having a physical thickness of between 45 and 50 nm, and optionally - a dielectric overlayer comprising silicon dioxide and having a physical thickness of between 8 and 10 nm.

[0047] In a second preferred embodiment of the invention, the stack comprises or is constituted by the succession of the following layers, starting from the surface of the glass substrate: - a dielectric sub-layer comprising silicon dioxide and having a physical thickness of between 8 and 10 nm, - a first layer comprising titanium nitride having a physical thickness of between 20 and 25 nm, - a second layer comprising silicon nitride having a physical thickness of between 45 and 50 nm, and optionally - a dielectric overlayer comprising silicon dioxide and having a physical thickness of between 8 and 10 nm.

[0048] The layers or coatings according to the invention are deposited by deposition techniques of the magnetic field-assisted vacuum sputtering type of a cathode of the material or a precursor of the material to be deposited, often called magnetron sputtering technique in the field. Such a technique is conventionally used today, in particular when the coating to be deposited consists of a stack of successive layers with thicknesses of a few nanometers or a few tens of nanometers. This layer deposition technique makes it possible to avoid the problems existing with other deposition techniques, such as CVD deposition.

[0049] In particular, the glass articles according to the invention are durable over time, in the sense that their initial properties, in particular their neutral coloring and their optical properties, vary only very slightly under chemical attacks, such as corrosion, or under mechanical attacks to which they are subjected during their intended use.

[0050] They can thus be advantageously used as single or monolithic glazing (a single glass substrate), or as multiple glazing, for example double glazing or even as laminated or laminated glazing.

[0051] According to a first alternative, the glass article is a glazing comprising only a single glass substrate (called single or monolithic glazing) and the stack of layers is arranged on the internal face of the glass substrate, face directed towards the interior of the building or vehicle (commonly called “face 2”).

[0052] According to a second alternative, said article is a laminated glazing unit consisting of a set of at least two glass substrates bonded together by a thermoplastic sheet, in particular polyvinyl butyral (PVB), said stack preferably being arranged on at least one face of one of the glass substrates facing the inside of said laminated glazing unit.

[0053] According to a third alternative, said article is a double glazing which is made up of two glass panels separated by a gas blade, said stack being arranged in preferably on at least one side of one of the glass panels facing the inside of said double glazing, in other words on “side 2” or “side 3” of the double glazing.

[0054] According to a fourth alternative, said article is a set of composite glazing consisting of laminated glazing, as described previously, included in a structure of the double glazing type, as described previously.

[0055] Furthermore, the glass article according to the invention comprises a stack of layers capable of undergoing a heat treatment such as tempering, bending or more generally a heat treatment at temperatures between 600°C and 750°C, preferably between 680°C and 715°C, without loss of its optical and thermal properties. The glass article according to the invention can thus be thermally tempered and / or bent.

[0056] The invention also relates to building glazing, in particular anti-solar glazing, comprising a glass article as defined above. However, 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, the car roof or the rear window.

[0057] 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. EXAMPLES

[0058] For comparison purposes, all the stacks of examples 1 to 8 which follow are synthesized on glass substrates mounted in single glazing.

[0059] All the layers of the stacks were deposited using conventional magnetron sputtering vacuum deposition techniques.

[0060] Example 1 (according to the invention)

[0061] In this example, the glass substrate has been covered with a stack of layers comprising the succession of the following layers starting from the surface of said glass substrate: - a first layer comprising titanium nitride, noted TiN, having a thickness of 25 nm, and - a second layer comprising silicon nitride, denoted Si3N4, having a thickness of 50 nm;

[0062] the cumulative thickness of the TiN and Si3N4 layers is therefore equal to 75 nm. Example 2 (according to the invention)

[0063] In this example, a sub-layer comprising silicon dioxide, denoted SiO2, and having a thickness of 10 nm, is added to the stack of example 1 and is placed below the TiN layer.

[0064] Example 3 (according to the invention)

[0065] In this example, the SiO2 sub-layer of the stack according to example 2 is replaced by a layer comprising silicon nitride, denoted Si3N4 and having a thickness of 10 nm. Example 4 (comparative)

[0066] In this example, the thickness of the Si3N4 sub-layer of the stack according to example 3 is equal to 20 nm. Example 5 (according to the invention)

[0067] In this example, an overlayer comprising silicon dioxide denoted SiO2, and having a thickness of 10 nm, is added to the stack of example 1 and is placed above the Si3N4 layer.

[0068] Example 6 (according to the invention)

[0069] In this example, a SiO2 overlayer having a thickness of 10 nm is added to the stack of Example 2 and is placed above the Si3N4 layer. Example 7 (comparative)

[0070] In this example, the glass substrate has been covered with a stack of layers comprising the succession of the following layers starting from the surface of said glass substrate: - a first layer comprising titanium nitride, noted TiN, having a thickness of 25 nm, and - a second layer comprising silicon nitride, denoted Si3N4, having a thickness of 35 nm; the cumulative thickness of the TiN and Si3N4 layers being therefore equal to 60 nm. Example 8 (comparative)

[0071] In this example, the glass substrate has been covered with a stack of layers comprising the succession of the following layers starting from the surface of said glass substrate: - a first layer comprising titanium nitride, noted TiN, having a thickness of 25 nm, and - a second layer comprising silicon nitride, denoted Si3N4, having a thickness of 70 nm; the cumulative thickness of the TiN and Si3N4 layers being therefore equal to 95 nm.

[0072] All the layers according to examples 1 to 8 above are deposited in a known manner by magnetic field-assisted cathode sputtering (often called magnetron).

[0073] ©The layer comprising titanium nitride is deposited from the sputtering of a metallic titanium target in a reactive atmosphere of argon and nitrogen containing 75% Ar and 25% N2 by volume.

[0074] >The layer(s) comprising silicon nitride, called “substantially stoichiometric” (N / Si ratio ~ 1.33 > to 1.25) are deposited in compartments of the device from metallic silicon targets (doped with 8 mol% of aluminum), in a reactive atmosphere of argon and nitrogen containing 60% Ar and 40% N2 by volume. These silicon nitride layers therefore contain a little aluminum, and are denoted Si3N4 for convenience, knowing that the actual stoichiometry can be significantly different in particular due to this doping (see the explanations previously provided in the description of the present application).

[0075] ©The silicon dioxide layer(s) are obtained by the sputtering technique from a metallic silicon target in an atmosphere containing 30 cm3 / min of Ar and 20 cm3 / min of O2.

[0076] The conditions for magnetron deposition of such layers are technically well known and mastered in the field.

[0077] Table 1 below groups together the information concerning the constitution of the anti-solar stacks 1 to 3 and 5, 6, according to the invention and the constitution of the stacks 3, 7 and 8 outside the invention:

[0078] [Tableauxl] Example Underlayer First layer Second layer Overlayer 1 (inv.) - TiN 25 nm Si3N4 50 nm - 2 (inv.) SiO2 10 nm TiN 25 nm Si3N4 50 nm - 3 (inv.) Si3N4 10 nm TiN 25 nm Si3N4 50 nm - 4 (comp.) Si3N4 20 nm TiN 25 nm Si3N4 50 nm - 5 (inv.) - TiN 25 nm Si3N4 50 nm SiO2 10 nm 6 (inv.) SiO2 10 nm TiN 25 nm Si3N4 50 nm SiO2 10 nm 7 (comp.) - TiN 25 nm Si3N4 35 nm - 8 (comp.) - TiN 25 nm Si3N4 70 nm -

[0079] All the substrates according to examples 1 to 8 are made of 4 mm thick clear glass of the Planiclear™ type marketed by the company Saint-Gobain Glass France. And the anti-solar glazings obtained according to examples 1 to 8 above are used as single glazings.

[0080] A-Measurement of the characteristics of the glazing The optical characteristics of the single anti-solar glazings obtained according to the examples described above were measured in accordance with the European standard NF EN 410 (2011). More precisely, the light transmissions TL, the external light reflections RLext on the side of the face of the glazing with the glass substrate not covered with layers and the internal light reflections RLint on the side of the face of the glazing supporting the stack of layers, are measured in the visible spectrum range: wavelengths between 380 nm and 780 nm, according to illuminant D65.

[0081] The colorimetry parameters a*T and b*T in transmission, the colorimetry parameters a*ext and b*ext in external reflection as well as the colorimetry parameters a*int and b*int in internal reflection are measured according to the international colorimetry model (L, a*, b*).

[0082] B-Results The results obtained for monolithic (single) glazing according to the examples described previously are grouped in Table 2 below:

[0083] [Tables2] Examples tl a*T b*T RLext Q ext b*ext RLint a*int U int 1 (inv.) 45.0 -2.3 2.4 30.9 -4.0 -1.0 2.6 -4.6 -14.1 2 (inv.) 44.6 -2.3 2.5 31.0 -4.2 -0.5 2.6 -4.6 -14.2 3 (inv.) 46.5 -2.5 1.1 28.5 -5.0 1.1 2.3 -2.4 -9.9 4 (comp.) 49.2 -2.9 0.1 24.3 -5.1 7.5 2.1 3.2 -9.1 5 (inv.) 44.3 -2.1 2.8 31.9 -4.4 0.6 3.3 -5.9 -15.4 6 (inv.) 47.0 -2.4 1.8 31.5 -4.8 -4.0 3.2 -5.9 -12.0 7 (comp.) 46.0 -3.1 0.9 23.2 -1.9 -11.1 4.9 5.2 0.1 8 (comp.) 42.0 -1.6 4.6 32.5 -2.4 18.0 11.9 -4.1 -13.4

[0084] The results reported in this table show that the single glazings according to the invention, corresponding to examples 1, 2, 3, 5 and 6, have good anti-solar properties, with high light transmission (TL > 40%) and high external reflection (RLext > 28%), and a neutral tint whether in transmission or in external reflection (with colorimetric coordinate values: a*T, b*T and a*ext and b*ext between -5 and -5) thus meeting the desired aesthetic criteria, while retaining very low internal reflection (RLint < 4%), therefore without mirror effect.

[0085] The single glazings according to the invention consist of a small number of layers (two layers according to example 1, three layers according to examples 2, 3, 5 and four layers according to example 4), each of said layers being of small thickness (between 10 nm and 50 nm).

[0086] From Table 2 above, it can be seen that the glazing according to Example 3, according to the invention, whose Si3N4 dielectric sub-layer, arranged between the surface of the glass substrate and the first TiN layer, has a physical thickness equal to 15 nm, has a higher external light reflection (RLext = 28.5) and a rather neutral external reflection coloration (a*ext = -5.0 and b*ext = -1.1) compared to the RLext of the glazing of Comparative Example 4 and its green coloration (RLext = 24.3 / a*ext = -5.1 and b*ext = 7.5), whose dielectric sub-layer thickness is equal to 20 nm.

[0087] It can also be noted that the single glazing prepared in accordance with the invention (example 1, whose cumulative TiN + Si3N4 thickness is equal to 75 nm) presents a good compromise between external reflection and internal reflection; since a high external reflection is obtained (RLext = 30.9) and a reflection very low interior light reflection is obtained (RLint = 2.6), and a neutral coloration in reflection on the glass substrate side is obtained (a*ext = -4.0 and b*ext = -1.0) in comparison with: - the glazing of comparative example 7, whose cumulative thickness of TiN and Si3N4 is less than 70 nm, since an exterior light reflection of only 23.2 is obtained and a blue coloration of the glazing on the glass side is obtained (a*ext = -1.9 and b*ext = -11.1), - the glazing of comparative example 8, whose cumulative thickness of TiN and Si3N4 is greater than 80 nm, since a higher interior light reflection of 11.9 is obtained and a green coloration of the glazing on the glass side (a*ext = -2.4 and b*ext = -18.0) is obtained.

Claims

Claims

1. Glass article comprising at least one glass substrate on which a stack of layers is deposited, said stack of layers comprising the succession of the following layers starting from the surface of said glass substrate: - a first layer comprising titanium nitride having a physical thickness of between 20 and 32 nm, said first layer being arranged above a dielectric sub-layer having a physical thickness of between 5 nm and 10 nm, said sub-layer being arranged between said surface and said first layer and preferably directly in contact with them, - a second layer comprising silicon nitride, the cumulative physical thickness of the first layer and the second layer being between 70 and 80 nm, and said stack comprising a single layer comprising titanium nitride and said titanium nitride layer being the only functional layer of the stack of layers.

2. A glass article according to claim 1, wherein the dielectric underlayer comprises silicon nitride or silicon dioxide or silicon oxynitride, preferably silicon dioxide.

3. A glass article according to any preceding claim, wherein the undercoat is deposited directly onto and in contact with the glass substrate.

4. Glass article according to any one of the preceding claims, in which the stack further comprises a dielectric overlayer placed above the second layer comprising silicon nitride, said dielectric overlayer having a physical thickness less than or equal to 15 nm and a refractive index measured at 550 nm less than or equal to 1.

6.

5. A glass article according to claim 4, wherein the overcoat comprises silicon dioxide.

6. Glass article according to claim 4 or 5, in which the dielectric overlayer is in direct contact with said second layer.

7. A glass article according to any preceding claim, wherein the stack further incorporates between the first layer comprising titanium nitride and the second layer comprising silicon nitride, a metallic layer, said metallic layer comprising chromium, nickel, niobium or a mixture of at least two of these elements, said metallic layer being optionally nitrided and / or optionally having a thickness less than or equal to 5 nm.

8. Glass article according to any one of the preceding claims, in which each of said layers of the stack is in direct contact with the previous one.

9. A glass article according to any preceding claim, wherein the stack does not comprise layers based on Ag, Au, Pt, Cu or stainless steel.

10. Glass article according to any one of the preceding claims, characterized in that it has, in the wavelength range of the visible spectrum, a light transmission greater than or equal to 35%, an external light reflection greater than or equal to 26% and an internal light reflection less than or equal to 8%.

11. Glass article according to any one of the preceding claims, characterized in that it is thermally toughened and / or curved.

12. Building glazing, in particular anti-solar glazing, comprising a glass article according to any one of the preceding claims.