FR3131741A1 - Solar control glazing - Google Patents

Abstract

The invention relates to a multiple glazing unit comprising at least two substrates separated by at least one spacer gas layer, the substrate constituting the outer wall of the glazing unit comprises on its face facing the interior a stack of layers comprising at least one functional metallic layer based on silver and at least two dielectric coatings, each dielectric coating comprising at least one dielectric layer, so that each functional metallic layer is placed between two dielectric coatings, characterized in that the stack comprises a coating based on titanium oxide comprising, as deposited, an oxidation gradient, located above and in contact with a silver-based functional metal layer, the part of the oxidation gradient coating in contact with the functional layer is less oxidized than the part of this coating further from the functional layer.

Description

Solar control glazing

The invention relates to solar protection glazing. Known high-performance solar protection glazing is multiple glazing comprising at least two substrates separated by at least one spacer gas blade. The substrate constituting the exterior wall of the glazing comprises on its inward facing side a stack of layers comprising at least one functional layer based on silver.

The functional silver-based metallic layers (or silver layers) have advantageous electrical conduction and reflection properties of infrared (IR) radiation, hence their use in these so-called “solar control” glazings aimed at reducing the amount of solar energy entering a building or vehicle.

These silver layers are deposited between coatings based on dielectric materials generally comprising several dielectric layers (hereinafter “dielectric coatings”) making it possible to adjust the optical properties of the stack. These dielectric layers also make it possible to protect the silver layer from chemical or mechanical attacks.

There is a strong demand for solar protection glazing combining the following properties:
- high light transmission, in particular at least 70%, 75% or even 78%,
- a low or moderate solar factor,
- low heat loss resulting in low Ug coefficients in particular 1.15 W/m ² .K, 1.10 W/m ² .K, or even 1.00 W/m ² .K.

The solar factor of the glazing “FS or g” corresponds to the ratio in % between the total energy entering the room through the glazing and the incident solar energy. The solar factor therefore measures the contribution of glazing to the heating of the “room”. The smaller the solar factor, the lower the solar gains.

The heat loss coefficient, also called “Ug value”, expresses the heat flow per square meter of glazing caused by a temperature difference existing between the exterior environment and the interior separated by the glazing. The lower this value, the lower the losses and the better the insulation.

It is very difficult to achieve sufficiently low absorption with multi-functional silver-based stacks. This is notably due to the presence of at least four “metal/dielectric” interfaces which each necessarily generate absorption. Preferably, the invention is limited to stacks comprising a single functional layer based on silver because they are likely to have lower visible light absorption values and therefore higher light transmissions.

Obtaining such a high light transmission, low solar factor and low heat loss in combination is difficult because very few modifications to the stacking are possible. To obtain such low heat loss at these levels of light transmission, in particular with stacks with a single functional layer based on silver, it is necessary to reduce the emissivity of the stack without increasing absorption or reflection. There is therefore no great flexibility of action.

Furthermore, these properties must be obtained even when the stack or the substrate carrying the stack has not undergone heat treatment at high temperature. This represents a significant additional constraint in the case of glazing with high light transmission. Generally, high temperature heat treatments such as annealing, bending and/or quenching cause changes within the silver layer leading to a decrease in emissivity. In the present case, we cannot count on an improvement attributable to heat treatment.

However, it is very difficult to reduce emissivity without reducing light transmission. Indeed, increasing the thickness of the silver layers makes it possible to lower the emissivity but at the expense of light transmission.

The emissivity depends directly on the quality of the silver layers such as their crystalline state, their homogeneity as well as their environment. By “environment” we mean the nature of the layers near the silver layer and the surface roughness of the interfaces with these layers. Another way to reduce emissivity therefore consists of improving the quality of the silver layer by choosing a favorable environment. Emissivity and resistivity (or resistance) per square vary proportionately. Therefore, it is often possible to evaluate the emissivity of a material by evaluating its resistance per square.

To improve the quality of the functional silver-based metal layers, it is known to use dielectric coatings under the silver layers comprising dielectric layers with a stabilizing function intended to promote wetting, nucleation and crystallization of the layer. silver. Dielectric layers based on crystallized zinc oxide are used in particular for this purpose. In fact, the zinc oxide deposited by the sputtering process crystallizes without requiring additional heat treatment. The zinc oxide-based layer can therefore serve as an epitaxial growth layer for the silver layer.

Another way to prevent the degradation of the silver layers lies in the choice of the layer located above and in contact with the silver layer. Among the known proposals are the use of so-called blocking layers or dielectric layers based on crystallized zinc oxide. The objective is to protect the functional layers from possible degradation during deposition of the upper dielectric coating and/or during heat treatment.

The blocking layers are generally based on a metal chosen from nickel, chromium, titanium, niobium, or an alloy of these different metals. The different metals or alloys mentioned can also be partially oxidized, in particular having a sub-stoichiometry in oxygen (for example TiOx or NiCrOx).

These blocking layers are very thin, normally less than 2 nm thick and are likely at these thicknesses to be partially oxidized during heat treatment or during the deposition of an overlying layer. Generally speaking, these blocking layers are sacrificial layers, capable of capturing oxygen coming from the atmosphere or the substrate, thus preventing the oxidation of the silver layer.

The use of these thin blocking layers does not make it possible to obtain sufficiently efficient glazing, in particular having a sufficiently low emissivity to obtain, in combination, high light transmission and sufficiently low heat losses.

Good results in terms of resistivity have been obtained until now with a material not comprising a blocking layer and in which each dielectric coating comprises at least one layer comprising silicon. The silver layer is located in contact with the two layers of crystallized zinc oxide located respectively above and below the silver layer. Materials of this type comprising the sequence ZnO/Ag/ZnO are qualified as reference material in the present application.

This solution consisting of using only layers based on crystallized zinc oxide below and above the silver does not give complete satisfaction either.

The applicant has surprisingly discovered that the use of a coating comprising an oxidation gradient based on titanium oxide located above and in contact with the functional layer based on silver, in a particular stack , makes it possible to overcome these disadvantages. The solution of the invention makes it possible to achieve the required properties, namely obtaining solar protection glazing having high light transmission, in particular of the order of 78.5% and low emissivity. The emissivity can in particular be low enough to make it possible to obtain the lowest possible heat transfer coefficients (Ug values).

The invention therefore relates to multiple glazing comprising at least two substrates separated by at least one interposed gas blade, the substrate constituting the exterior wall of the glazing comprises on its face turned towards the inside a stack of layers comprising a functional metal layer with silver base and at least two dielectric coatings, each dielectric coating comprising at least one dielectric layer, so that each functional metal layer is arranged between two dielectric coatings, characterized in that the stack comprises a silver-based coating titanium oxide comprising, as deposited, an oxidation gradient, located above and in contact with the functional silver-based metallic layer, the part of the coating with an oxidation gradient in contact with the functional layer is less oxidized than the part of this coating further from the functional layer.

The stack includes a coating comprising an oxidation gradient as deposited. This means that a coating with an oxidation gradient is directly deposited. The gradient is present from the deposition. The gradient is not obtained following a possible heat treatment, the deposition of an overlying layer or a possible long storage.

The applicant has surprisingly discovered that the solution of the invention makes it possible to obtain an improvement in resistivity with the obtaining of a gain in square resistance of at least 10%, or even 15%, even in the absence of thermal treatment. In some embodiments, the improvement in resistivity is achieved without increasing absorption. This gain in resistivity makes it possible to achieve emissivity values low enough to reach the required Ug values without increasing the thickness of the silver layer and therefore without reducing light transmission.

This solution therefore makes it possible to achieve high levels of light transmission, even in the case of stacks used as deposited, i.e. without being subjected to subsequent treatment at high temperature. For these stacks, the quality of the silver layers does not make it possible to obtain resistances per square as low as in the case of hardened or laser-treated stacks. Obtaining low Ug values requires the use of thicker silver layers which prevent sufficiently high levels of light transmission. The gain in resistance per square obtained thanks to the solution of the invention makes it possible to circumvent this difficulty.

Preferably, the dielectric coating located below the silver layer comprises a layer with a high refractive index. The joint presence of the coating based on titanium oxide which has a high refractive index above the functional layer based on silver and a high index layer below the functional layer contributes to obtaining 'high light transmission.

The applicant has also surprisingly discovered that the use of the coating comprising an oxidation gradient based on titanium oxide associated with a layer based on zinc and tin oxide in particular contributes to obtaining the properties advantageous of the invention. It seems that this layer makes it possible to reduce the residual absorption in the event of non-complete oxidation of the part furthest from the silver layer of the oxidation gradient coating based on titanium oxide. The invention combining a coating based on titanium oxide in contact with a layer of zinc and tin oxide makes it possible to obtain:
- an improvement in resistivity with obtaining a gain in square resistance of at least 5%, or even 10% or more, for certain structures of the invention, both before and after heat treatment,
- an improvement in the mechanical properties of brush resistance before and after heat treatment.

The present invention is particularly suitable in the case of stacks with a single functional layer based on silver. The solution of the invention is also suitable in the case of stacks with several functional layers based on silver, in particular stacks with two or three functional layers.

The material according to the invention may have the following characteristics alone or in combination:
- the oxidation gradient coating comprises at least two layers of titanium oxide each comprising different proportions of oxygen,
- the oxidation gradient coating comprises a first layer deposited from a ceramic target, in particular under stoichiometry, in an atmosphere whose percentage in volume flow rate of oxygen represents between 0 and 4%, preferably 0%,
- the first layer has a thickness of between 0.2 and 2 nm,
- the oxidation gradient coating comprises a second layer based on titanium oxide deposited from a ceramic target, in particular under stoichiometry, in an atmosphere comprising higher proportions of oxygen than that used for the first layer ,
- the second layer has a thickness of between 0.2 and 30 nm,
- the stack further comprises a layer based on zinc and tin oxide comprising at least 10% by mass of tin relative to the total mass of zinc and tin, located above and in contact of the layer based on titanium oxide,
- the layer based on zinc and tin oxide has a thickness:
- greater than 5 nm,
- less than 40 nm.
- the dielectric coating located above the functional layer comprises a layer comprising silicon chosen from silicon nitride layers,
- the dielectric coating located below the functional layer comprises a layer based on zinc oxide located in contact with the functional layer,
- the dielectric coating located below the functional layer further comprises a layer with a refractive index greater than 2.20,
- the layer with a refractive index greater than 2.20 is chosen from layers based on titanium oxide and layers based on silicon nitride and zirconium,
- the thickness of all layers with a refractive index greater than 2.20 in the dielectric coating located below the functional layer is greater than 10 nm, greater than 15 nm, greater than 20 nm,
- the dielectric coating located above the functional layer comprises a layer based on silicon nitride and zirconium,
- the dielectric coating located below the functional layer comprises a layer based on silicon nitride and zirconium,
- it has a light transmission greater than 70%, greater than 75%, greater than 76% or greater than 78%,
- it has a Ug value less than 1.15 W/m ² .K, less than 1.10 W/m ² .K or less than 1.00 W/m ² .K,
- the stack comprises a single functional metallic layer based on silver,
- the stack was subjected to rapid thermal annealing,
- the stack and the substrate have been subjected to heat treatment at a high temperature above 500°C such as quenching, annealing or bending.

The invention also relates to:
- glazing according to the invention mounted on a vehicle or on a building, and
- the use of glazing according to the invention as solar control glazing for buildings or vehicles,
- a building, a vehicle or a device comprising glazing according to the invention.

Throughout the description, the substrate according to the invention is considered laid horizontally. The stack of thin layers is deposited on top of the substrate. The meaning of the expressions “above” and “below” and “lower” and “superior” must be considered in relation to this orientation. In the absence of specific stipulation, the expressions “above” and “below” do not necessarily mean that two layers and/or coatings are placed in contact with each other. When it is specified that a layer is deposited “in contact” with another layer or a coating, this means that there cannot be one (or more) layer(s) interposed between these two layers (or layer and coating).

All the light characteristics described are obtained according to the principles and methods of European standards EN 410 relating to the determination of the light and solar characteristics of glazing used in glass for construction. The method for calculating the Ug coefficient of insulating glazing is described in standard NF EN 673. It is considered that solar light entering a building goes from the outside to the inside.

According to the invention, the luminous characteristics are measured according to the illuminant D65 at 2° perpendicular to the material mounted in double glazing:
- TL corresponds to the light transmission in the visible in %,
- Rext corresponds to the exterior light reflection in the visible in %, observer side exterior space,
- Rint corresponds to the interior light reflection in the visible in %, observer side interior space,
- a*T and b*T correspond to the transmission colors a* and b* in the L*a*b* system,
- a*Rext and b*Rext correspond to the reflected colors a* and b* in the L*a*b* system, observer on the exterior space side,
- a*Rint and b*Rint correspond to the colors in reflection a* and b* in the L*a*b* system, observer on the interior space side.

As explained previously, according to the invention the properties must be obtained even when the stack or the substrate carrying the stack has not undergone heat treatment at high temperature.

The stacks according to the invention can be used interchangeably:
- as deposited, that is to say without having been subjected to any heat treatment at high temperature, in this case neither the substrate coated with the stack, nor the stack alone, has undergone heat treatment at high temperature high,
- treated by laser radiation, in this case, only the stack undergoes heat treatment at high temperature,
- treated by annealing or quenching, in this case the substrate and the stack undergo heat treatment at high temperature.

The present invention therefore relates to the non-heat-treated coated substrate. The stack may not have undergone heat treatment at a temperature above 500°C, preferably 300°C.

The present invention also relates to the coated substrate of the heat-treated stack. The heat treatments are chosen from:
- annealing, for example rapid annealing,
- quenching and/or bending.

The material, that is to say the transparent substrate coated with the stack, may have undergone heat treatment at high temperature. The stack and the substrate may have been subjected to heat treatment at an elevated temperature such as quenching, annealing or bending.

It is also possible to heat treat only the stack. In this case, only the stack may have undergone heat treatment.

In these two cases, the stack may have undergone heat treatment at a temperature above 300°C, preferably 500°C. The heat treatment temperature (at the stack level) is greater than 300°C, preferably greater than 400°C, and better still greater than 500°C.

According to the invention, it is also possible to carry out rapid thermal annealing (“Rapid Thermal Process”) such as laser or flash lamp annealing. Rapid thermal annealing is for example described in applications WO2008/096089 and WO2015/185848. In these cases, only the stack is subjected to heat treatment. During this type of treatment, each point of the stack is brought to a temperature of at least 300 ^° C while maintaining a temperature less than or equal to 150 ^° C at any point on the face of the substrate opposite to that on which it is placed. locate the stack. This process has the advantage of only heating the stack, without significant heating of the entire substrate.

In the case of laser processing, the coated materials can be treated using a laser line formed from laser sources such as InGaAs laser diodes or Yb:YAG disk laser. These continuous sources emit at a wavelength between 900 and 1100 nm. The laser line has a length of around 3.3 m, equal to the width 1 of the substrate, and an average width at half-height FWHM between 45 and 100 µm.

The materials are arranged on a roller conveyor so as to move in a direction X, parallel to its length. The laser line is fixed and positioned above the coated surface of the substrate with its longitudinal direction Y extending perpendicular to the direction extending over this entire width.

The position of the focal plane of the laser line is adjusted to lie within the thickness of the functional coating when the substrate is positioned on the conveyor. The surface power of the laser line at the focal plane is less than 100kW/cm2. The substrate was moved under the laser line at a speed of approximately 8 m/min.

The stack may therefore have been subjected to rapid thermal annealing in which each point of the stack is brought to a temperature of at least 300 ^° C while maintaining a temperature less than or equal to 150 ^° C at any point on the face. of the substrate opposite to that on which the stack is located.

It is also possible to combine heat treatments. For example, it is possible to carry out rapid thermal annealing followed by quenching.

The stack and the substrate may have been subjected to heat treatment at a high temperature above 500°C such as quenching, annealing or bending.

The substrate coated with the stack can be curved or tempered glass.

The stack is deposited by cathode sputtering assisted by a magnetic field (magnetron process). According to this advantageous embodiment, all the layers of the stack are deposited by cathode sputtering assisted by a magnetic field.

In the absence of specific stipulation, the expressions “above” and “below” do not necessarily mean that two layers and/or coatings are placed in contact with each other. When it is specified that a layer is deposited “in contact” with another layer or a coating, this means that there cannot be one (or more) layer(s) interposed between these two layers (or layer and coating).

Unless otherwise stated, the thicknesses mentioned in this document are physical thicknesses and the layers are thin layers. By thin layer is meant a layer having a thickness of between 0.1 nm and 100 micrometers.

In the present description, unless otherwise indicated, the expression "based on", used to qualify a material or a layer as to what it contains, means that the mass fraction of the constituent which it comprises is at least 50%, in particular at least 70%, preferably at least 90%.

The stack may comprise a single functional silver-based metal layer.

The silver-based metallic functional layers comprise at least 95.0%, preferably at least 96.5% and better still at least 98.0% by mass of silver relative to the mass of the functional layer. Preferably, a silver-based functional metal layer comprises less than 1.0% by mass of metals other than silver relative to the mass of the silver-based functional metal layer.

The silver-based metallic functional layers have a thickness:
- greater than 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm or 16 nm, and/or
- less than 25nm, 22nm, 20nm, 18.nm.

Dielectric coatings include dielectric layers. By “dielectric layer” within the meaning of the present invention, it must be understood that from the point of view of its nature, the material is “non-metallic”, that is to say it is not a metal. In the context of the invention, this term designates a material having an n/k ratio over the entire visible wavelength range (from 380 nm to 780 nm) equal to or greater than 5. n designates the index of real refraction of the material at a given wavelength and k represents the imaginary part of the refractive index at a given wavelength; the ratio n/k being calculated at a given wavelength which is identical for n and for k.

The thickness of a dielectric coating corresponds to the sum of the thicknesses of the layers constituting it. Preferably, the dielectric coatings have a thickness greater than 10 nm, greater than 15 nm, between 15 and 200 nm, between 15 and 100 nm or between 15 and 70 nm.

The dielectric layers of the coatings have the following characteristics alone or in combination:
- they are deposited by magnetic field-assisted cathode sputtering,
- they have a thickness greater than 2 nm, preferably between 4 and 200 nm.

The dielectric layers, in addition to their optical function, can have various other functions. As an example, we can cite stabilizing layers, smoothing layers, and barrier layers.

The dielectric layers are conventionally chosen from layers based on oxide, based on nitride or based on oxynitride. The oxide layers of one or more elements comprise mainly oxygen and very little nitrogen. The oxide-based layers include in particular at least 90% in atomic percentage of oxygen relative to the oxygen and nitrogen in said layer. Nitride-based layers consist mainly of nitrogen and very little oxygen. The nitride-based layers comprise at least 90 atomic percent nitrogen relative to the oxygen and nitrogen in said layer. Oxynitride-based layers include a mixture of oxygen and nitrogen. The layers based on silicon oxynitride comprise 10 to 90% (limits excluded) in atomic percentage of nitrogen relative to the oxygen and nitrogen in said layer.

The quantities of oxygen and nitrogen in a layer are determined as atomic percentages relative to the total quantities of oxygen and nitrogen in the layer considered.

The dielectric layers are conventionally chosen from:
- the layers comprising silicon, aluminum and/or zirconium, optionally doped with at least one other element,
- layers based on zinc and tin oxide,
- layers based on titanium oxide,
- layers based on zinc oxide.

The stack comprises a coating comprising an oxidation gradient based on titanium oxide located above and in contact with a functional metallic layer based on silver, the part of the oxidation gradient coating in contact with the functional layer is less oxidized than the part of this coating further from the functional layer.

According to the invention, the titanium oxide coating is described as it is deposited, that is to say before a possible heat treatment or before a possible long storage. Indeed, heat treatment at high temperature or long storage can generate modifications within layers or coatings. These modifications may in particular correspond to a rearrangement of the oxygen atoms within the coating making it more difficult to observe the gradient.

The oxidation gradient coating has a thickness:
- greater than 3 nm, greater than 4 nm, greater than or equal to 5 nm, greater than or equal to 8 nm, greater than or equal to 10 nm, greater than or equal to 8 nm,
- less than or equal to 30 nm, less than or equal to 25 nm, less than or equal to 20 nm, less than or equal to 15 nm, less than or equal to 10 nm, less than or equal to 8 nm.

The oxidation gradient coating may include:
- a layer of titanium oxide comprising an oxygen gradient,
- at least two layers of titanium oxide comprising different proportions of oxygen.

The layers based on titanium oxide comprise at least 50%, at least 60%, at least 70%, at least 80%, at least 95.0%, at least 96.5% and better still at least 98.0 % by mass of titanium relative to the mass of all the elements constituting the layer based on titanium oxide other than oxygen.

The titanium oxide-based layers may include or consist of elements other than titanium and oxygen. These elements can be chosen from silicon, chromium and zirconium. Preferably, the elements are chosen from zirconium.

Preferably, the layer based on titanium oxide comprises at most 35%, at most 20% or at most 10% by mass of elements other than titanium relative to the mass of all the elements constituting the layer based on titanium oxide. titanium oxide other than oxygen.

The layers based on titanium oxide can have a thickness:
- greater than or equal to 2 nm, greater than or equal to 3 nm, greater than or equal to 4 nm, greater than or equal to 5 nm, and/or
- less than or equal to 30 nm, less than or equal to 25 nm, less than or equal to 20 nm, less than or equal to 15 nm, less than or equal to 10 nm, less than or equal to 8 nm, less than or equal to 4 nm.

Layers based on titanium oxide can be obtained:
- by cathode sputtering,
- from a metallic titanium target or a ceramic target based on titanium oxide, preferably under stoichiometry.

When the titanium oxide-based layer is obtained from a metallic target, the deposition atmosphere includes significant proportions of oxygen.

The layers based on titanium oxide are preferably obtained from a ceramic target of titanium oxide, preferably under oxygen stoichiometry, in an atmosphere comprising oxygen or without oxygen. The quantity of oxygen in the deposition atmosphere can be adapted according to the desired properties.

According to the preferred embodiment, a layer based on titanium oxide is deposited from a ceramic target, in particular under stoichiometry. The titanium oxide-based layer can be deposited from a sub-stoichiometric TiO _x ceramic target, where x is a number different from the stoichiometry of the titanium oxide TiO ₂ , i.e. different from 2 and preferably less than 2, in particular between 0.75 times and 0.99 times the normal stoichiometry of the oxide. TiOx can in particular be such that 1.5 < x < 1.98 or 1.5 < x < 1.7, or even 1.7 < x < 1.95.

The layers based on titanium oxide can be deposited in an atmosphere not containing oxygen or in a controlled atmosphere including oxygen.

According to the invention, the term “controlled atmosphere comprising oxygen” means an atmosphere comprising an optimized quantity of oxygen to obtain the desired properties.

The deposition atmosphere includes a mixture of noble gas (He, Ne, Xe, Ar, Kr) and oxygen. The noble gas is preferably argon.

The following parameters allow you to define the conditions for deposition by sputtering:
- the deposition pressure,
- the composition of the gases in volume flow (scm unit “standard cubic centimeter per minute”).

The controlled atmosphere making it possible to obtain the advantageous effects of the invention was obtained in particular with the following parameters:
- the pressure in the deposition enclosure is between 1 and 15 µbar, preferably 2 and 10 µbar or 2 and 8 µbar,
- the deposition atmosphere includes a mixture of argon and oxygen.

The controlled atmosphere making it possible to obtain the advantageous effects of the invention was obtained with an oxygen volume flow percentage of between 0 and 20%. The maximum oxygen threshold may vary to some extent depending on, for example:
- the nature of the TiOx target, in particular its oxygen substoichiometry or
- power,
- the configuration of the cathode sputtering deposition chamber (geometry, locations of gas inlets, etc.)

Indeed, if a low deposition power is used, the quantities of oxygen volume flow that can be used during deposition will be lower because the TiOx is deposited more slowly and is therefore more likely to oxidize.

Those skilled in the art are able to define a satisfactory controlled atmosphere by varying these parameters to a certain extent. Those skilled in the art are particularly able to determine the power to be applied to the target and the volume flow rates of oxygen and noble gases.

For this, for a given deposition pressure, those skilled in the art are able to make increasing additions of oxygen in order to determine the range of oxygen proportion which makes it possible to lower the resistivity after heat treatment without harming the 'absorption.

The oxidation gradient coating may comprise at least one layer based on titanium oxide deposited from a ceramic target, in particular under stoichiometry, in a controlled atmosphere comprising oxygen, preferably in a controlled atmosphere comprising oxygen. The titanium oxide-based layer can be deposited with a percentage of oxygen in volume flow between 0 and 20%.

The oxidation gradient coating may comprise at least two layers of titanium oxide each comprising different proportions of oxygen, i.e. different degrees of oxidation.

In this case, the coating is obtained by deposition of at least two consecutive layers based on titanium oxide. This deposition in several stages makes it possible to obtain in the majority of the coating a layer of titanium oxide with a large quantity of oxygen, while protecting the functional layer based on silver with a first layer of titanium oxide weakly oxidized. The absorption of the stack before heat treatment is then greatly reduced. The oxidation gradient coating can therefore comprise a first layer deposited from a ceramic target, in particular under stoichiometry, in an oxygen-free atmosphere.

The oxidation gradient coating may comprise a first layer based on titanium oxide deposited from a ceramic target, in particular under stoichiometry, in a non-oxidizing or oxidizing atmosphere whose percentage in volume flow rate of oxygen represents between 0 and 5%, between 0 and 4%, between 0 and 3%, between 0 and 2%. This first layer based on titanium oxide is in contact with the functional layer based on silver.

The quantity of oxygen in the first layer based on titanium oxide must be relatively low so as not to degrade the functional layer based on silver. For this, we can use a first layer deposited from a ceramic target, in particular under stoichiometry, in an atmosphere without oxygen or with very little oxygen. However, using a little oxygen contributes to better resistance to the brush test without inducing too much absorption penalty, particularly before heat treatment.

The thickness of the first layer based on titanium oxide can be as thin as that of a standard blocking layer (<1nm), as long as the functional layer based on silver does not prove to be degraded by the oxygen present during the deposition of the next layer based on titanium oxide, deposited with more oxygen than the first.

The first layer has a thickness between 0.2 and 4nm. The first layer may have a thickness of less than 3 nm, less than 2 nm or less than 1 nm or less than 0.5 nm.

The oxidation gradient coating comprises a second layer based on titanium oxide deposited from a ceramic target, in particular under stoichiometry, in an atmosphere comprising higher proportions of oxygen than that used for the first layer.

The second layer based on titanium oxide can be deposited from a metallic target or a ceramic target.

The second layer based on titanium oxide can be deposited from a ceramic target, in particular under stoichiometry, in an oxidizing atmosphere whose percentage of oxygen in volume flow represents between 1 and 15%.

The second layer based on titanium oxide has a thickness of between 0.2 and 30 nm, between 2 and 20 nm or between 5 and 15 nm.
The second layer based on titanium oxide can have a thickness:
- greater than 0.5 nm, greater than 1 nm, greater than 2 nm, greater than 3 nm, greater than 4 nm, greater than 5 nm,
- less than 30 nm, less than 20 nm, less than 15 nm or less than 10 nm.

The oxidation gradient coating may also include a single layer of titanium oxide comprising an oxygen gradient.

A coating based on titanium oxide comprising a single oxygen gradient layer can be obtained:
- by cathode sputtering,
- in an atmosphere comprising a mixture of neutral gas and oxygen, by gradually increasing the flow rates of oxygen present in the atmosphere,
- from a metallic titanium target or a ceramic target based on titanium oxide, preferably under stoichiometry.

In this case, the volume flow of oxygen in the deposition atmosphere is gradually increased as the layer based on titanium oxide is deposited. The part of the coating with an oxidation gradient in contact with the functional layer is less oxidized than the part of this coating further away from the functional layer.

Typically, when the target is a ceramic target under oxygen stoichiometry, the proportions of oxygen in the deposition atmosphere can vary from 0% to 15%.

According to the invention, the titanium oxide-based layers of the gradient coating form part of a dielectric coating. This means that when determining the thickness of a dielectric coating, we take into consideration the thickness of these layers.

The gradient coating is below and in contact with a dielectric layer. The dielectric layer may be based on oxide, nitride or oxynitride of one or more elements chosen from silicon, zirconium, titanium, aluminum, tin and/or zinc. Preferably, this dielectric layer has a thickness greater than 5 nm, 8 nm, 10 nm or 15 nm.

The stack may comprise at least one layer comprising silicon. Preferably, the dielectric coating located above the silver-based functional layer may comprise a layer comprising silicon. Each dielectric coating may also comprise at least one layer comprising silicon.

The layers comprising silicon are extremely stable to thermal treatments. For example, we do not observe migrations of the elements constituting them. Consequently, these elements are not likely to alter the silver layer. Layers comprising silicon therefore also contribute to the non-alteration of the silver layers and therefore to obtaining a low emissivity after heat treatment.

The layers comprising silicon comprise at least 50% by mass of silicon relative to the mass of all the elements constituting the layer comprising silicon other than nitrogen and oxygen.

The layers comprising silicon can be chosen from layers based on oxide, based on nitride or based on oxynitride such as layers based on silicon oxide, layers based on silicon nitride and layers based on silicon oxynitride.

The silicon oxide-based layers comprise at least 90 atomic percent oxygen relative to the oxygen and nitrogen in the silicon oxide-based layer. The silicon nitride-based layers include at least 90 atomic percent nitrogen relative to the oxygen and nitrogen in the silicon nitride-based layer. The layers based on silicon oxynitride comprise 10 to 90% (excluding limits) in atomic percentage of nitrogen relative to the oxygen and nitrogen in the layer based on silicon oxide. Preferably, the layers based on silicon oxide are characterized by a refractive index at 550 nm, less than or equal to 1.55. Preferably, the layers based on silicon nitride are characterized by a refractive index at 550 nm, greater than or equal to 1.95.

The layers comprising silicon may comprise or consist of elements other than silicon, oxygen and nitrogen. These elements can be chosen from aluminum, boron, titanium, and zirconium. The layers comprising silicon may comprise at least 2%, at least 5% or at least 8% by mass of aluminum relative to the mass of all the elements constituting the layer comprising silicon other than oxygen and nitrogen.

The layers comprising aluminum can be chosen from layers based on oxide, based on nitride or based on oxynitride such as layers based on aluminum oxide such as Al2O3, layers based on aluminum nitride such as AIN and layers based on aluminum oxynitride such as AlOxNy.

The layers based on silicon nitride and zirconium Si _x Zr _y N _z are part of the layers comprising silicon, in particular layers based on silicon nitride.

The refractive index of the layers based on silicon nitride and zirconium increases with the increase in the proportions of zirconium in said layer.

The silicon nitride-based layers may include aluminum and/or zirconium. Such layers may include, in atomic proportion relative to the atomic proportion of Si, Zr and Al:
- 50 to 98%, 60 to 90%, 60 to 70 atomic% of silicon,
- 0 to 10%, 2 to 10 atomic % of aluminum,
- 0 to 30%, 10 to 40% or 15 to 30 atomic% of zirconium.

Preferably, the dielectric coating located above the silver layer comprises a layer comprising silicon. These layers comprising silicon have, in order of increasing preference, a thickness:
- less than or equal to 40 nm and/or
- greater than or equal to 5 nm, greater than or equal to 10 nm or greater than or equal to 15 nm.

Preferably, at least one dielectric coating comprises a layer comprising silicon chosen from layers based on silicon nitride. Preferably, the dielectric coating located above the functional layer based on silver comprises a layer comprising silicon chosen from layers based on silicon nitride. Each dielectric coating may comprise a layer comprising silicon chosen from layers based on silicon nitride.

Preferably, the sum of the thicknesses of all layers comprising silicon in the dielectric coating located above the first functional silver-based metal layer may be greater than 35%, greater than 50%, of the total thickness. of the dielectric coating.

Preferably, the sum of the thicknesses of all layers comprising silicon based on silicon nitride in each dielectric coating located above the first functional metal layer based on silver can be greater than 35%, greater than 50% , of the total thickness of the dielectric coating.

The stack may comprise a layer based on zinc and tin oxide comprising at least 10% by mass of tin relative to the total mass of zinc and tin, located above and in contact with the layer based on titanium oxide.

The layer based on zinc and tin oxide comprises in mass of tin relative to the total mass of zinc and tin:
- at least 10%, at least 15%, at least 20%, at least 30%, at least 40%, at least 45%, at least 50% or at least 55%,
- not more than 90%, not more than 80%, not more than 70%, not more than 65% or not more than 60% by mass of zinc.
The layer based on zinc and tin oxide located in the dielectric coating above the functional layer based on silver has a thickness:
- greater than 5 nm, greater than 10 nm, greater than 15 nm, greater than 18 nm,
- less than 40 nm, less than 30 nm, less than 25 nm.

The dielectric coating located above the silver layer may include:
- the gradient coating,
- a layer comprising silicon, preferably a layer based on silicon nitride or a layer based on silicon nitride and zirconium or a combination of these two layers.

The dielectric coating located above the silver layer may include:
- the gradient coating,
- a layer based on zinc and tin oxide comprising at least 10% by mass of tin relative to the total mass of zinc and tin, located above and in contact with the layer based on tin titanium oxide,
- a layer comprising silicon, optionally located above and in contact with the layer based on zinc and tin oxide, preferably a layer based on silicon nitride or a layer based on silicon nitride and zirconium or a combination of these two layers.

The dielectric coating located below the silver layer may include a so-called stabilizing layer which reinforces the adhesion of the functional layer to the layers surrounding it. The stabilizing layers are preferably layers based on zinc oxide optionally doped, for example, with aluminum. The zinc oxide is crystallized. The layer based on zinc oxide comprises, in increasing order of preference, at least 90.0%, at least 92%, at least 95%, at least 98.0% by mass of zinc relative to the mass of elements other than oxygen in the zinc oxide-based layer.

According to this embodiment, the dielectric coating located below the functional layer may further comprise a layer based on zinc oxide located directly in contact with it. Indeed, it is advantageous to have a stabilizing layer, below and in contact with a functional layer, because it facilitates the adhesion and crystallization of the silver-based functional layer and increases its quality and stability. . The metallic functional layer is deposited above and in contact with a layer based on zinc oxide. The zinc oxide-based layer can be deposited from a ceramic target, with or without oxygen or from a metallic target. The zinc oxide layers have a thickness:
- at least 1.0 nm, at least 2.0 nm, at least 3.0 nm, at least 4.0 nm, at least 5.0 nm, at least 6.0nm and/or
- not more than 25 nm, not more than 10 nm, not more than 8.0 nm.

The dielectric coating located below the silver layer may also comprise a layer based on zinc and tin oxide comprising at least 20% by mass of tin relative to the total mass of zinc and tin. , located below and in contact with the zinc oxide-based layer.

The stack can therefore comprise one or more layers based on zinc and tin oxide comprising at least 10% by mass of tin relative to the total mass of zinc and tin, located above and at the bottom. contact of the layer based on titanium oxide. The layers based on zinc and tin oxide preferably comprise by mass of tin relative to the total mass of zinc and tin:
- at least 10%, at least 15%, at least 20%, at least 30%, at least 40%, at least 45%, at least 50% or at least 55%,
- not more than 90%, not more than 80%, not more than 70%, not more than 65% or not more than 60% by mass of zinc.
The layers based on zinc and tin oxide have a thickness:
- greater than 5 nm, and/or
- less than 40 nm, less than 30 nm, less than 25 nm.

Preferably, the dielectric coating located below the silver layer comprises a layer with a high refractive index. The presence of high index layers above and below the silver-based functional layer contributes to obtaining high light transmission.

Among the dielectric layers, we distinguish, depending on their refractive index at 550 nm, layers with a low refractive index, layers with an intermediate refractive index and layers with a high refractive index. Low to low refractive index layers have a refractive index less than 1.70. Intermediate refractive index layers have a refractive index between 1.70 and 2.2. High refractive index layers have a refractive index greater than 2.2.

High refractive index layers can be chosen from:
- layers based on titanium oxide (n550=2.4),
- layers based on mixed titanium oxide and another component chosen from the group consisting of Zn, Zr and Sn,
- the layers based on a layer of zirconium nitride (n 550 = 2.55),
- layers based on silicon nitride and zirconium (n550 nm = 2.20 - 2.40),
- the layers based on a layer of zirconium oxide,
- layers based on manganese oxide MnO (n550 = 2.16),
- the layers based on a layer of tungsten oxide (n550 = 2.15),
- the layers based on a layer of niobium oxide (n550 = 2.30),
- layers based on a layer of bismuth oxide (n 550 = 2.60).
Preferably, the high refractive index layer is chosen from the layers based on titanium oxide and the layer based on silicon nitride and zirconium.

Preferably, the stack does not include a metallic or titanium oxide-based blocking layer below and in contact with the functional silver-based metallic layer. In this case, the functional silver-based metal layer is located above and in contact with a dielectric layer of the dielectric coating. Preferably, this dielectric layer is a stabilizing layer.

The dielectric coating located below the silver layer may comprise a sequence of layers, defined starting from the substrate, chosen from:
- layer based on titanium oxide (high index layer) // layer based on zinc oxide,
- layer based on silicon nitride // layer based on zinc oxide,
- layer based on silicon nitride and zirconium (high index layer) // layer based on zinc oxide,
- layer based on silicon nitride // layer based on silicon nitride and zirconium (high index layer) // layer based on zinc oxide,
- layer based on silicon nitride // layer based on titanium oxide (high index layer) // layer based on zinc oxide,
- layer based on silicon nitride and zirconium (high index layer) // layer based on titanium oxide (high index layer) // layer based on zinc oxide,
- layer based on silicon nitride // layer based on silicon nitride and zirconium // layer based on titanium oxide (high index layer) // layer based on zinc oxide,
- layer based on titanium oxide (high index layer) // layer based on zinc and tin oxide // layer based on zinc oxide,
- layer based on silicon nitride // layer based on zinc and tin oxide // layer based on zinc oxide,
- layer based on silicon nitride and zirconium (high index layer) // layer based on zinc and tin oxide // layer based on zinc oxide,
- layer based on silicon nitride // layer based on silicon nitride and zirconium (high index layer) // layer based on zinc and tin oxide // layer based on zinc oxide,
- layer based on silicon nitride // layer based on titanium oxide (high index layer) // layer based on zinc and tin oxide // layer based on zinc oxide?
- layer based on silicon nitride and zirconium // layer based on titanium oxide (high index layer) // layer based on zinc and tin oxide // layer based on zinc oxide ,
- layer based on silicon nitride // layer based on silicon nitride and zirconium // layer based on titanium oxide (high index layer) // layer based on zinc and tin oxide / / layer based on zinc oxide.

When the stack includes a layer of silicon nitride and a layer of silicon nitride and zirconium, these layers are different, that is to say they are not composed of the same elements in the same proportions.

The dielectric coating located above the silver layer may comprise a sequence of layers, defined starting from the substrate, chosen from:
- the oxidation gradient coating // layer based on silicon nitride,
- the oxidation gradient coating // layer based on silicon nitride and zirconium,
- the oxidation gradient coating // layer based on silicon nitride and zirconium // layer based on silicon nitride,
- the oxidation gradient coating // layer based on zinc and tin oxide // layer based on silicon nitride,
- the oxidation gradient coating // layer based on zinc and tin oxide // layer based on silicon oxide,
- the oxidation gradient coating // layer based on zinc and tin oxide // layer based on silicon nitride and zirconium,
- the oxidation gradient coating // layer based on zinc and tin oxide // layer based on silicon nitride and zirconium // layer based on silicon nitride,
- the oxidation gradient coating // layer based on zinc and tin oxide // layer based on silicon nitride // layer based on zinc and tin oxide,
- the oxidation gradient coating // layer based on silicon nitride // layer based on silicon oxide,
- the oxidation gradient coating // layer based on zinc and tin oxide // layer based on silicon nitride // layer based on silicon oxide,
- the oxidation gradient coating // layer based on silicon nitride and zirconium // layer based on silicon nitride // layer based on silicon oxide.

The stack of thin layers may optionally include a protective layer. The protective layer is preferably the last layer of the stack, that is to say the layer furthest from the coated substrate of the stack (before heat treatment). These layers generally have a thickness of between 0.5 and 10 nm, between 1 and 5 nm, between 1 and 3 nm or between 1 and 2.5 nm. This protective layer can be chosen from a layer of titanium, zirconium, hafnium, silicon, zinc and/or tin, this or these metals being in metallic, oxidized or nitrided form. According to one embodiment, the protective layer is based on zirconium oxide and/or titanium oxide, preferably based on zirconium oxide, titanium oxide or titanium and zirconium oxide. When determining the thickness of a dielectric coating, we take into account the thickness of the protective layer.

The transparent substrates according to the invention are preferably made of a rigid mineral material, such as glass, or organic based on polymers (or polymer).

The organic transparent substrates according to the invention can also be made of polymer, rigid or flexible. Examples of polymers suitable according to the invention include, in particular:
- polyethylene,
- polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN);
- polyacrylates such as polymethyl methacrylate (PMMA);
- polycarbonates;
- polyurethanes;
- polyamides;
- polyimides;
- fluoropolymers such as fluoroesters such as ethylene tetrafluoroethylene (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), ethylene of chlorotrifluoroethylene (ECTFE), ethylene-propylene fluorinated copolymers (FEP);
- photocrosslinkable and/or photopolymerizable resins, such as thiolene, polyurethane, urethane-acrylate, polyester-acrylate and
- polythiourethanes.

The substrate is preferably a sheet of glass or glass ceramic.

The substrate is preferably transparent, colorless (it is then a clear or extra-clear glass) or colored, for example blue, gray or bronze. The glass is preferably of the soda-lime-silico type, but it can also be of borosilicate or alumino-borosilicate type glass. According to a preferred embodiment, the substrate is made of glass, in particular silico-soda-lime or of polymeric organic material.

The substrate advantageously has at least one dimension greater than or equal to 1 m, or even 2 m and even 3 m. The thickness of the substrate generally varies between 0.5 mm and 19 mm, preferably between 0.7 and 9 mm, in particular between 2 and 8 mm, or even between 4 and 6 mm. The substrate can be flat or curved, or even flexible.

The invention relates to glazing in the form of multiple glazing, in particular double glazing or triple glazing.
Double glazing has 4 faces, face 1 is outside the building and therefore constitutes the exterior wall of the glazing, face 4 is inside the building and therefore constitutes the interior wall of the glazing, faces 2 and 3 being inside the double glazing. The stack according to the invention is on face 2.
Triple glazing has 6 faces, face 1 is outside the building and therefore constitutes the exterior wall of the glazing, face 6 is inside the building and therefore constitutes the interior wall of the glazing, faces 2 and 3 and 4 and 5 being inside the double glazing. The stack according to the invention can be located on face 2 and/or on face 5.
These glazings can be mounted on a building or a vehicle.

The following examples illustrate the invention.

Examples

I. Preparation of substrates: Stacks, deposition conditions
Stacks of thin layers defined below are deposited on clear soda-lime glass substrates with a thickness of 4 mm. In the examples of the invention:
- the functional layers are silver layers (Ag),
- the dielectric layers are based on silicon nitride doped with aluminum (Si₃NOT₄: Al), based on aluminum-doped silicon zirconium nitride (SiZrN: Al), based on zinc and tin oxide, based on zinc oxide (ZnO).
TiOx titanium oxide layers are deposited from a ceramic TiOx target with or without oxygen in the deposition atmosphere.
The conditions for deposition of the layers, which were deposited by sputtering (so-called “cathode magnetron sputtering”), are summarized in Table 1.

Materials Composition target Pressure Power Gas sccm Ar _O2 No. ₂ Ar/O ₂ (90/10) ZnO ZnO:Al 2%wt ceramic 2 µbar 1300W 40 2 - - TiOx_0% TiOx ceramic 2 µbar 2000W 30 0 - - TiOx_10% TiOx ceramic 2 µbar 2000W 30 03 - SnZnO Sn:Zn 60/40%wt metallic 2 µbar 1000W 7 44 Ag Ag metallic 8 µbar 210W 80 - - - Si3N4 Si:Al 8%wt metallic 2 µbar 2000W 18 - 24 - SiZrN Si:Zr 27% at metallic 2 µbar 1000W 15 - 15 -

%wt: % by weight; at%: atomic.

In all examples, the stacks according to the invention comprise coatings based on titanium oxide (oxygen gradient coating) comprising at least two layers of titanium oxide comprising different proportions of oxygen. The first layer is deposited in contact with the silver layer in an oxygen-free atmosphere with a thickness of 1 nanometer. This layer is therefore under-oxidized. The second layer based on titanium oxide is deposited in an atmosphere with 10% oxygen in volume flow and has a thickness of at least 5 nm. This layer is therefore more oxidized than the first.

I.1. Glazing with non-heat-treated stacking
The following stacks have been developed to be used as deposited, i.e. without having been subjected to any heat treatment at high temperature. Neither the coated substrate of the stack, nor the stack alone, has undergone heat treatment at high temperature.
For this first series of examples, we seek to obtain a light transmission of 78.5% and a resistance per square of 2.3 Ω/□.
The table below lists the materials and physical thicknesses in nanometers (unless otherwise indicated) of each layer or coating which constitutes the stacks according to their positions with respect to the substrate carrying the stack.

Materials Layers Ref.1 I.1a I.1b I.1c Rev. dielectric TiOx 1 1 1 1 If ₃ N ₄ 25 22 20 14 SiZrN - - 8 - SnZnO - - - 10 TiOx 10% O2 13 19 13 18 ZnO 5 - - - TiOx: 0% O2 1 1 1 1 Functional layer Ag 17.4 16.2 16.2 16.2 Rev. dielectric ZnO 5 5 5 5 TiOx 22 22 15 22 SiZrN - - 8 - Substrate (mm) glass 4 4 4 4

In all the tables showing the optical and performance characteristics, the characteristics have been measured on double glazing with a 4/16/4 structure: 4 mm glass / 16 mm interspace filled with 90% argon and 10% d air/glass of 4 mm, the stack being positioned on face 2 (face 1 of the glazing being the outermost face of the glazing, as usual).
The square resistance Rsq, corresponding to the resistance referred to the surface, is measured by induction with a Nagy SMR-12.
The selectivity “s” corresponds to the TL/g ratio.
Glazing units each comprising the stacks described above were tested.

Glazing g s TL a*T b*T RLext has* b* RLint has* b* Rsq U g VRef.1 49.6 1.53 76.1 -3.9 3.8 16.0 3.5 -6.8 14.8 5.4 -8.5 2.30 1.11 VI.1a 52.8 1.49 78.5 -3.0 3.5 14.0 1.5 -7.5 13.1 3.3 -8.4 2.30 1.11 VI.1b 53.0 1.48 78.5 -3.0 3.5 14.1 1.5 -7.6 13.2 3.2 -8.4 2.30 1.11 VI.1c 52.8 1.49 78.5 -3.1 3.5 14.0 1.9 -7.5 13.1 3.6 -8.3 2.30 1.11

In the case of the reference stack Ref. 1 does not include a gradient coating, a light transmission of 78.5% cannot be obtained when imposing the constraint on the resistivity of at least 2.3 Ω/□. To achieve this value of 2.3 Ω/□, a layer of 17 nm of silver is necessary. However, it is not possible to achieve light transmission values greater than 76% with such thicknesses.

In the case of the glazing of the invention VI.1a, VI.1b and VI.1c, comprising on face 2, a stack comprising a gradient coating based on titanium oxide, it is possible to jointly obtain a light transmission of 78.5% and resistance values per square of 2.3 Ω/□. The gain in resistivity provided by the use of the thick coating based on titanium oxide makes it possible to obtain the value of 2.3 Ω/□, with a thinner layer of silver. These thinner thicknesses of silver make it possible to obtain high light transmission values, notably around 78.5%.

In conclusion, in the case of stacking used "as deposited", the invention makes it possible to obtain high light transmissions while maintaining resistivity values low enough to achieve low emissivity and thus a lower Ug value. .

We also note the obtaining of more neutral colors in external reflection, that is to say less red (value of a* closer to 0).

We note that the substitution of part of the TiOx layer by silicon and zirconium nitride in each dielectric coating leads to similar results (comparison VI.1a and VI.1b).

Finally, the use of a layer of zinc and tin oxide in contact with the thick layer based on titanium oxide (VI.1c) also leads to similar results in terms of solar factor, light transmission and resistivity. This layer, however, aims to reduce the residual absorption that may result from the incomplete oxidation of the TiOx. In addition, the introduction of this layer based on zinc and tin oxide improves mechanical resistance. This results in particular in improved results compared to the following tests:
- Erichsen scratch test (EST),
- Erichsen Brush Test (EBT) before and after quenching at 1000 cycles.

The Erichsen Brush Test (EBT) consists of subjecting different coated substrates to a certain number of cycles (1000) during which the stack covered with water is rubbed using a brush. A substrate is considered to satisfy the test if no mark is visible to the naked eye. The EBT test before tempering gives a good indication of the ability of the glazing to be scratched during a washing operation with water using a brush.

The Erichsen scratch test (EST) consists of applying a force to the sample, in Newton, using a point (Van Laar point, steel ball). Depending on the scratch resistance of the stack, different types of scratches can be obtained: continuous, discontinuous, wide, narrow, etc.

I.2. Glazing with stack treated by laser radiation
The following stacks have been developed for use after being subjected to laser heat treatment. In this case, only the stack undergoes heat treatment at high temperature. The coated substrates were processed using a laser line formed from a disk laser. The following conditions were used:
- disk laser source: Yb:YAG,
- wavelength: 1030nm,
- width: 60µm,
- power density: 70kW/cm².

The table below lists the materials and physical thicknesses in nanometers (unless otherwise indicated) of each layer or coating which constitutes the stacks according to their positions with respect to the substrate carrying the stack.

Materials Layers Ref.2 I.2a I.2b I.2c Rev. dielectric TiOx 1 1 1 1 If ₃ N ₄ 18 22 19 13 SiZrN - - 13 - SnZnO - - - 11 TiOx 17 18 8 17 ZnO 5 - - - TiOx: 0% O2 1 1 1 1 Functional layer Ag 15.7 16.1 16.1 16.1 Rev. dielectric ZnO 5 5 5 5 TiOx 21 21 15 21 SiZrN - - 6 - Substrate (mm) glass 4 4 4 4

For this series of examples, we seek to obtain a light transmission of 78.5% and the lowest possible resistance per square.

Glazing g s TL a*T b*T RLext has* b* RLint has* b* Rsq U g VRef.2 53.2 1.48 78.5 -2.9 3.5 14.4 1.4 -7.3 13.4 3.0 -8.1 2.02 1.09 VI.2a 52.9 1.48 78.5 -2.9 3.5 14.4 1.4 -7.1 13.5 3.0 -7.9 1.76 1.08 VI.2b 53.0 1.48 78.5 -2.9 3.5 14.5 1.5 -7.2 13.5 3.0 -7.9 1.76 1.08 VI.2c 52.9 1.48 78.5 -2.9 3.5 14.5 1.4 -6.9 13.5 3.0 -7.7 1.77 1.08

For a given light transmission value, the glazing according to the invention has the lowest values of solar factor (-0.3%) and resistance per square (1.76 vs. 2.02 Ω/□). In all cases, the solution of the invention makes it possible to obtain the specifications of the glazing more easily.
Substitution of a part of the thickness of the TiOx layer with silicon and zirconium nitride in each dielectric coating leads to similar results (comparison VI.2a and VI.2b).
Finally, the use of a layer of zinc and tin oxide in contact with the thick layer based on titanium oxide (VI.2c) also leads to similar results in terms of solar factor, light transmission and resistivity.
This layer, however, aims to reduce the residual absorption that may result from the incomplete oxidation of the TiOx following laser treatment.

I. 3 . Glazing with stack treated by tempering type heat treatment
The following stacks have been developed for use after being subjected to a quenching type heat treatment. The heat treatments are carried out in the NABER oven at a temperature of 650°C for 10 minutes.

Materials Layers Ref.3 I.3a I.3b I.3c Rev. dielectric TiOx 1 1 1 1 If ₃ N ₄ 19 27 24 19 SiZrN 17 - 11 SnZnO - - - 10 TiOx 10% - 15 8 15 ZnO 5 - - - TiOx: 0% O2 - 1 1 1 NiCr 0.7 Functional layer Ag 15.1 15.7 15.7 15.7 Rev. dielectric ZnO
SiZrN 5
22 5
22 5
22 5
22 Substrate (mm) glass 4 4 4 4

For this series of examples, we seek to obtain a light transmission of 78.5% and the lowest possible resistance per square of 2.3 Ω/□.

g s TL a*T b*T RLext has* b* RLint has* b* Rsq U g V Ref.3 54.1 1.45 78.5 -2.9 3.5 14.1 1.6 -7.8 13.2 3.0 -7.9 2.13 1.09 VI.3 53.6 1.46 78.5 -2.8 3.5 14.5 1.6 -7.4 13.5 3.0 -7.8 1.82 1.10

The glazing of the invention VI.3a has a lower solar factor (-0.5%) and a lower resistance per square (1.82 vs. 2.13Ω/□) for the same level of light transmission.
Equivalent results were obtained with stacks 3b and 3c comprising respectively:
- a high index layer based on silicon nitride and zirconium in the upper dielectric coating (I.3b),
- a layer based on zinc and tin oxide in the upper dielectric coating (3c).
For these examples according to the invention undergoing a quenching type treatment, we also observe:
- a reduction in resistivity,
- improved scratch resistance with:
- less visible scratches,
- if present, an absence of hot corrosion of existing scratches.

The examples concerning the embodiment in which the TiOx layer is in contact with a layer of zinc and tin oxide show that the combination of the invention allows:
- not to increase absorption after heat treatment,
- to obtain a gain in square resistance,
- to obtain good resistance to corrosion and the absence of blur,
- to obtain good resistance to the brush test after heat treatment.

Thanks to the solution of the invention combining a thin under-oxidized layer and a thicker oxidized layer, we limit absorption and therefore contribute to obtaining high light transmission.

Claims (20)

Multiple glazing comprising at least two substrates separated by at least one interposed gas blade, the substrate constituting the outer wall of the glazing comprises on its face turned towards the inside a stack of layers comprising a functional metallic layer based on silver and at least two dielectric coatings, each dielectric coating comprising at least one dielectric layer, so that each functional metal layer is placed between two dielectric coatings, characterized in that the stack comprises a coating based on titanium oxide comprising, as deposited, an oxidation gradient, located above and in contact with the functional silver-based metal layer, the part of the oxidation gradient coating in contact with the functional layer is less oxidized than the part of this coating further away from the functional layer. Glazing according to the preceding claim characterized in that the oxidation gradient coating comprises at least two layers of titanium oxide each comprising different proportions of oxygen. Glazing according to any one of the preceding claims, characterized in that the oxidation gradient coating comprises a first layer deposited from a ceramic target, in particular under stoichiometry, in an atmosphere whose percentage in volume flow rate of oxygen represents between 0 and 4%, preferably 0%. Glazing according to one of the preceding claims, characterized in that the first layer has a thickness of between 0.2 and 2 nm. Glazing according to any one of claims 2 to 4 characterized in that the oxidation gradient coating comprises a second layer based on titanium oxide deposited from a ceramic target, in particular under stoichiometry, in an atmosphere comprising higher proportions of oxygen than that used for the first layer. Glazing according to claim 5 characterized in that the second layer has a thickness of between 0.2 and 30 nm. Glazing according to any one of the preceding claims, characterized in that the stack further comprises a layer based on zinc oxide and tin comprising at least 10% by mass of tin relative to the total mass of zinc. and tin, located above and in contact with the layer based on titanium oxide. Glazing according to the preceding claim characterized in that the layer based on zinc and tin oxide has a thickness:
- greater than 5 nm,
- less than 40 nm. Glazing according to any one of the preceding claims, characterized in that the dielectric coating located above the functional layer comprises a layer comprising silicon chosen from silicon nitride layers. Glazing according to any one of the preceding claims, characterized in that the dielectric coating located below the functional layer comprises a layer based on zinc oxide located in contact with the functional layer. Glazing according to any one of the preceding claims, characterized in that the dielectric coating located below the functional layer further comprises a layer with a refractive index at 550 nm greater than 2.20. Glazing according to the preceding claim, characterized in that the layer with a refractive index greater than 2.20 is chosen from layers based on titanium oxide and layers based on silicon nitride and zirconium. Glazing according to claim 11 or 12 characterized in that the thickness of all layers with a refractive index greater than 2.20 in the dielectric coating located below the functional layer is greater than 10 nm. Glazing according to any one of the preceding claims, characterized in that the dielectric coating located above the functional layer comprises a layer based on silicon nitride and zirconium. Glazing according to any one of the preceding claims, characterized in that the dielectric coating located below the functional layer comprises a layer based on silicon nitride and zirconium. Glazing according to any one of the preceding claims, characterized in that it has a light transmission greater than 70%, greater than 75%, greater than 76% or greater than 78%. Glazing according to any one of the preceding claims, characterized in that it has a Ug value less than 1.15 W/m ² .K, less than 1.10 W/m ² .K or less than 1.00 W/ m ² .K. Glazing according to any one of the preceding claims, characterized in that the stack comprises a single functional silver-based metal layer. 19. Glazing according to any one of claims 1 to 18 characterized in that the stack has been subjected to rapid thermal annealing. 0Glazing according to any one of claims 1 to 18 characterized in that the stack and the substrate have been subjected to a heat treatment at a high temperature above 500 °C such as quenching, annealing or bending.