Glazing panel

GLAZING

The invention relates to the field of glazing comprising a glass substrate, provided on at least one of its faces with a stack of thin layers.

For environmental reasons and linked to the concern to save energy, homes are now equipped with multiple, double or even triple glazing, often with layers with low emissivity properties, intended to limit heat transfer to the outside. of the dwelling. These glazings with a very low thermal transmission coefficient are however subject to the appearance of water condensation on their outer surface, in the form of mist or frost. In the event of a clear sky during the night, the heat exchange by radiation with the sky causes a drop in temperature which is no longer sufficiently compensated by the heat input from inside the home. When the temperature of the exterior surface of the glazing drops below the dew point, the water condenses on said surface, hindering visibility through the glazing in the morning, sometimes for several hours.

In order to solve this problem, it is known to have on face 1 of the glazing (the outer face) a layer with a low emissivity property, for example a layer of a transparent electrically conductive oxide (TCO) in order to reduce the radiative exchanges. with the sky. Requirement

WO 2007/115796 recommends, for example, the use of a stack comprising a TCO layer, a blocker layer and finally a photocatalytic layer.

Such a solution, although it effectively makes it possible to largely resolve the problems of water condensation, is not, however, devoid of drawbacks. If the thickness of the layers is not optimized, this solution significantly reduces the solar factor of the glazing. The solar factor corresponds to the fraction of solar energy transmitted by the glazing towards the interior of the dwelling, by direct transmission through the glazing and by re-emission of the radiation absorbed by the glazing towards the interior. However, it is important, especially in winter or in countries with a cold climate, to be able to maximize the solar heat input through the glazing in order to reduce heating costs.

The object of the invention is to obviate these drawbacks by proposing a glazing which can limit or even eliminate the appearance of condensation (mist or frost) on the external face, while penalizing the solar factor as little as possible, and therefore transfers. of heat towards the interior of the dwelling.

To this end, the invention relates to a glazing comprising a glass substrate provided on one of its faces, intended to form the face 1 of said glazing in the position of use, with a stack of thin layers comprising, since said substrate, a layer of a transparent electrically conductive oxide, an intermediate layer with a refractive index in a range ranging from 1.40 to 1.55 and of optical thickness Y, and a photocatalytic layer whose thickness optical X is at most 50 nm, said optical thicknesses X and Y, expressed in nanometers, being such that:

<img file="FR2963343A1_D0001.tif" />

-0.025 V &lt;y &lt;135._e

-0.018V

By “face 1” of the glazing is meant, as is customary in the art, the external face of the glazing which is intended to be positioned so as to be in contact with the exterior of the dwelling. The faces of a glazing are numbered starting from the outside, so that face 2 is the face opposite to face 1, in other words the other face of the same sheet of glass. In multiple glazing, comprising two or more sheets of glass, face 3 is the face of the second glass sheet of the glazing facing face 2, face 4 is the face opposite to face 3, etc.

The refractive indices are measured, for example by ellipsometry, for a wavelength of 550 nm. The optical thickness of a layer is the product of the physical thickness (also called geometric) of the layer and its refractive index.

The glazing according to the invention is preferably a multiple glazing, in particular double or triple, or even more, for example quadruple. These glazings in fact have a low thermal transmission coefficient, and are the most affected by the phenomenon of condensation. Double glazing is generally made up of two sheets of glass facing each other and leaving a layer of gas, for example air, argon, xenon or even krypton. There is generally at the periphery of the glazing, between the glass sheets, a spacer frame, in the form of a metal profile, for example of aluminum, secured to the glass sheets by an adhesive, the periphery of the glazing being sealed to the 'Using a mastic, for example silicone, polysulphides or polyurethane, to prevent any entry of moisture into the gas layer. To limit humidity, a molecular sieve is frequently placed in the spacer frame. Triple glazing is made in the same way, except that the number of glass sheets is three.

When the glazing according to the invention is a triple glazing, at least one other face, chosen from faces 2 to 5, is preferably coated with a stack with low emissivity properties. They may in particular be stacks of thin layers comprising at least one silver layer, the or each silver layer being placed between dielectric layers. By low emissivity is meant an emissivity generally of at most 0.1, in particular 0.05. Preferably, two other faces, in particular faces 2 and 5, are coated with such a stack. Other configurations are also possible, but less preferred: sides 2 and 3, 2 and 4, 3 and 4, 4 and 5, sides 2, 3 and 4, sides 2, 3 and 5, sides 2, 4 and 5, faces 2, 3, 4 and 5. Other types of stacks can be placed on the faces of the glazing, for example anti-reflective stacks, on face 2, 3, 4, 5 or 6.

When the glazing according to the invention is a double glazing, the face 2 is advantageously coated with a stack with low emissivity properties, in particular of the type of that which has just been described. Alternatively, the face 2 can be coated with a solar control stack, which is however not preferred because such a stack leads to a reduction in the solar factor.

The glazing according to the invention can be used like any type of glazing. It can be integrated into a facade, a roof, a veranda. It can be arranged vertically or tilted.

The glass substrate is preferably transparent and colorless (it is then a clear or extraclear glass). It can be colored, for example in blue, green, gray or bronze, but this embodiment, penalizing for the solar factor, is not preferred. The glass is preferably of the co-soda-lime type, but it can also be of borosilicate or aluminoborosilicate type glass. The thickness of the substrate is generally within a range ranging from 0.5 mm to 19 mm, preferably from 0.7 to 9 mm, in particular from 2 to 8 mm, or even from 4 to 6 mm. The same applies, where appropriate, to the other glass sheets of the multiple glazing.

The glass substrate is preferably of the float type, that is to say capable of having been obtained by a process consisting in pouring the molten glass onto a bath of molten tin (“float” bath). In this case, the stack can equally well be deposited on the “tin” side as on the “atmosphere” side of the substrate. The expression “atmosphere” and “tin” faces is understood to mean the faces of the substrate having been respectively in contact with the atmosphere prevailing in the float bath and in contact with the molten tin. The tin side contains a small surface quantity of tin which has diffused into the structure of the glass.

At least one glass sheet, including that provided with the stack which constitutes the heart of the invention, can be tempered or hardened, in order to impart improved mechanical strength properties to it. As described below, thermal quenching can also be used to improve the emissivity or photocatalytic properties of the layers. To improve the acoustic or burglar resistance properties of the glazing according to the invention, at least one sheet of glass of the glazing may be laminated to another sheet by means of an interlayer made of a polymer such as polyvinlybutyral (PVB ) or polyurethane (PU).

The layer of an electrically conductive transparent oxide is preferably a layer of fluorine-doped tin oxide (SnCh: F) or a layer of mixed indium tin oxide (ITO). Other layers are possible, including thin layers based on mixed oxides of indium and zinc (called "IZO"), based on zinc oxide doped with gallium or aluminum, based on titanium oxide doped with niobium, based on cadmium or zinc stannate, based on tin oxide doped with antimony. In the case of zinc oxide doped with aluminum, the doping rate (that is to say the weight of aluminum oxide relative to the total weight) is preferably less than 3%. In the case of gallium, the doping rate can be higher, typically within a range ranging from 5 to 6%. In the case of ITO, the atomic percentage of Sn is preferably within a range ranging from 5 to 70%, in particular from 10 to 60%. For the layers based on tin oxide doped with fluorine, the atomic percentage of fluorine is preferably at most 5%, generally from 1 to 2%.

These layers have good climatic durability, necessary when the stack is placed on face 1 of the glazing, which is not the case with other low-emitted layers, such as silver layers. The latter must imperatively be located on an internal face of the multiple glazing.

ITO is particularly preferred, especially with respect to SnO2: F. With higher electrical conductivity, its thickness can be smaller to obtain the same level of emissivity, which makes it possible to minimize the loss of solar factor. Easily deposited by a cathodic sputtering process, in particular assisted by a magnetic field, called “magnetron process”, these layers are distinguished by a lower roughness, and therefore a lower fouling. During the manufacture, handling and maintenance of glazing, the rougher layers indeed tend to trap various residues, which are particularly difficult to remove.

One of the advantages of fluorine-doped tin oxide, on the other hand, is its ease of deposition by chemical vapor deposition (CVD), which, unlike the sputtering process, does not require subsequent heat treatment, and can be used. implemented on the float flat glass production line.

The thickness of the TCO layer is adjusted, depending on the nature of the layer, so as to obtain the desired emissivity, which depends on the desired anticondensation performance. The emissivity of the TCO layer is preferably less than or equal to 0.4, especially 0.3. For ITO layers, the geometric thickness will generally be at least 40 nm, or even 50 nm and even 70 nm, and often at most 150 nm or 200 nm. For fluorine-doped tin oxide layers, the geometric thickness will generally be at least 120 nm, or even 200 nm, and often at most 500 nm.

When the glazing is intended to be placed in a vertical position, the emissivity is preferably at most 0.4, or even 0.3. In the case of tin oxide doped with fluorine, this generally requires geometric thicknesses of at least 120 nm, or even 200 nm. In the case of ITO, the geometric thickness will generally be at least 40 nm, or even 50 nm, often at most 150 nm.

When the glazing is intended to be placed in an inclined position, for example in roofing applications, the emissivity is preferably at most 0.3, or even 0.2 and even 0.18. The geometric thicknesses of fluorine-doped tin oxide will preferably be at least 300 nm, and those of ITO at least 60 nm, or even 70 or 100 nm and often at most 200 nm.

The term “emissivity” is understood to mean the normal emissivity at 283 K within the meaning of standard EN 12898.

The refractive index of the transparent electrically conductive oxide layer is preferably in a range from 1.7 to 2.5.

In order to optimize the effect of the invention, the refractive index of the intermediate layer is preferably at most 1.50, or even 1.48.

The intermediate layer is advantageously based on silica, or even consisting of silica. It is understood that the silica can be doped, or not be stoichiometric. By way of examples, silica can be doped with aluminum or boron atoms, with the aim of facilitating its deposition by cathode sputtering processes. In the case of chemical vapor deposition (CVD), the silica can be doped with boron or phosphorus atoms, which accelerate the deposition. The silica can also be doped with carbon or nitrogen atoms, in sufficiently low contents for the refractive index of the layer to remain within the above-mentioned ranges. Such an intermediate layer also has the advantage of protecting the TCO layer, providing it with better climatic durability as well as better resistance to quenching. In the case of TCO based on tin oxide doped with fluorine, the intermediate layer also has the advantage of smoothing the surface, reducing the abrasiveness of the layer.

The photocatalytic layer is preferably based on titanium oxide, in particular a layer of titanium oxide, in particular whose refractive index is in a range ranging from 2.0 to 2.5. The titanium oxide is preferably at least partially crystallized in the anatase form, which is the most active phase from the point of view of photocatalysis. Mixtures of anatase and rutile phase have also been shown to be very active. Titanium dioxide can optionally be doped with a metal ion, for example an ion of a transition metal, or with nitrogen, carbon, fluorine atoms, etc. Titanium dioxide can also be sub- stoichiometric or over-stoichiometric. If titanium oxide is clearly preferred, other photocatalytic oxides can also be employed, among which SrTiCb, ZnO, Sic, GaP, CdS, CdSe, M0S3, SnO₂, ZnO, WO3, Fe₂O3, Bi₂O3, Nb₂O5, KTaCg, BiVCy, Bi₂WO6 In the glazing according to the invention, the entire surface of the photocatalytic layer, in particular based on titanium oxide, is preferably in contact with the outside, so as to be able to fully implement its self-cleaning function. It may however be advantageous to coat the photocatalytic layer, in particular made of titanium dioxide, with a thin hydrophilic layer, in particular based on silica in order to improve the persistence of hydrophilicity over time.

The optical thickness X of the photocatalytic layer, in particular based on titanium oxide, is preferably at most 40 nm, in particular 30 nm. Its geometric thickness is advantageously at most 20 nm, or even 15 nm, or even 10 nm, and preferably greater than or equal to 5 nm. Very thin layers, although less photocatalytically active, nevertheless have good self-cleaning, anti-fouling and anti-fog properties. Even for very thin layers, photocatalytic titanium oxide indeed has the particularity, when it is irradiated by sunlight, of becoming extremely hydrophilic, with contact angles with water of less than 5 ° and even 1 °, which allows the water to run off more easily, by eliminating the dirt deposited on the surface of the layer. In addition, thicker layers have a higher light reflection, which has the effect of lowering the solar factor.

According to one possible embodiment, no layer is placed between the transparent electroconductive layer and the intermediate layer, and / or between the intermediate layer and the photocatalytic layer. Alternatively, a protective layer can be placed between the TCO layer, in particular when it is made of ITO, and the intermediate layer. This layer, the thickness of which is advantageously at most 10 nm, in particular 5 nm, or even 2 nm, makes it possible to protect the TCO, in particular the ITO, during the deposition of the intermediate layer, in particular when the deposition is carried out by cathodic sputtering, and during any subsequent heat treatments. The refractive index of the protective layer is preferably greater than or equal to that of the TCO layer. Particularly preferred is silicon nitride.

It is also possible to have, between the substrate and the layer of an electrically conductive transparent oxide, a neutralization layer, or a stack of layers. In the case of a single layer, its refractive index is preferably between the refractive index of the substrate and the refractive index of said layer of a transparent electrically conductive oxide. Such layers or stacks of layers make it possible to influence the appearance in reflection of the glazing, in particular on its color in reflection. Bluish colors, characterized by negative b * color coordinates, are preferred. By way of nonlimiting examples, it is possible to use a mixed oxide layer of silicon and tin (SiSnO_x), silicon oxycarbide or oxynitride, aluminum oxide, mixed oxide of titanium and silicon. A stack of layers comprising two high and low index layers, for example a TiCt / SiCu, Si3N stack₄/ SiO2 or TCO / SiO2 can also be used (in the latter case, the TCO can be the same as that already used in the stack, or another TCO). The geometric thickness of this or these layer or layers is preferably in a range from 15 to 70 nm. When the layer of an electrically conductive transparent oxide is of fluorine-doped tin oxide, the neutralization sublayer is preferably of silicon oxycarbon or of mixed oxide of silicon and tin. When the layer of an electroconductive transparent oxide is made of ITO, a neutralization layer of a silicon oxynitride or an Si3N stack is preferably placed under this layer.₄/ SiO2.

In particular when the layer of an electrically conductive transparent oxide is made of ITO, it is preferable to place an adhesion layer between the substrate and the neutralization layer or stack. This layer, which advantageously has a refractive index close to that of the glass substrate, makes it possible to improve the resistance to toughening by promoting the attachment of the neutralization layer. The adhesion layer is preferably made of silica. Its geometric thickness is preferably within a range ranging from 20 to 200 nm, in particular from 30 to 150 nm.

The various preferred embodiments described above can of course be combined with one another. All the possible combinations are of course not explicitly described in the present text. Some particularly preferred examples of stacks are given below.

<td>Glass</td><td> /</td><td>SiOC /</td><td>SnO₂ : F</td><td> /</td><td>SiO₂</td><td> /</td><td>TiO₂</td>

<td>Glass</td><td> /</td><td>SiSnO_x</td><td>/ SnO₂:</td><td>F /</td><td>SiO₂</td><td> /</td><td>TiO₂</td>

<td>Glass</td><td> /</td><td>(SiO₂)</td><td>/ SiO_xNOT</td><td colspan="2">y / ITO</td><td> /</td><td>Yes₃NOT₄ / SiO₂ / TiO₂</td>

<td>Glass</td><td> /</td><td>(SiO₂)</td><td>/ Yes₃NOT₄</td><td> /</td><td>SiO₂</td><td> /</td><td>ITO / Si₃NOT₄ / SiO₂</td>

TiO₂

In these stacks, the geometric thickness of the TiO layer₂ is advantageously at most 15 nm, or even 10 nm. The thickness of the TCO layer is to be chosen independently, as a function of the desired emissivity, as explained further on in the present description.

Stacks 1 and 2 use a TCO layer of fluorine-doped tin oxide. These stacks are preferably obtained by chemical vapor deposition, generally directly on the float line of the glass.

Stacks 3 and 4, which use ITO, are preferably obtained by magnetron sputtering. They contain on the glass an adhesion layer of silica (optional), then a neutralization layer of silicon oxynitride or a neutralization stack consisting of a layer of silicon nitride surmounted by a layer of silica, the TCO layer. , a protective layer of silicon nitride, an intermediate layer of silica and finally the photocatalytic layer of titanium dioxide. The formulas given do not prejudge the real stoichiometry of the layers, and any doping.

The glazing according to the invention is preferably obtained by a process in several stages. The layers of the stack are deposited on the glass substrate, which then generally takes the form of a large glass sheet of 3.2 * 6m², or directly on the glass ribbon during or just after the floating process, then the substrate is cut to the final dimensions of the glazing. After shaping the edges, the multiple glazing is then manufactured by combining the substrate with other sheets of glass, themselves optionally provided beforehand with functional coatings, for example of the low-emissivity type.

The different layers of the stack can be deposited on the glass substrate by any type of thin film deposition process. They may for example be sol-gel, pyrolysis (liquid or solid) type processes, chemical vapor deposition (CVD), in particular assisted by plasma (APCVD), optionally at atmospheric pressure (APPECVD), evaporation.

According to a preferred embodiment, the layers of the stack are obtained by chemical vapor deposition, directly on the production line of the glass sheet by float. The deposition is carried out by spraying precursors through nozzles on the hot glass ribbon. The different layers can be deposited at different places on the line: in the float chamber, between the float chamber and the lehr, or in the lehr. The precursors are generally organometallic molecules or of the halide type. By way of examples, mention may be made, for tin oxide doped with fluorine, of tin tetrachloride, mono-beta tin tri chloride (MTBCL), trifluoroacetic acid, hydrofluoric acid. The silicon oxide can be obtained using silane, tetraethoxysilane (TEOS), or even hexamethyldisiloxane (HDMSO), optionally using an accelerator such as triethylphosphate. Titanium oxide can be obtained from titanium tetrachloride or titanium isopropoxide. The CVD process, which implements a deposition on hot glass, has the advantage of directly obtaining a TCO layer and a well crystallized photocatalytic layer.

According to another preferred embodiment, the layers of the stack are obtained by cathodic sputtering, in particular assisted by a magnetic field (magnetron process). In this process, a plasma is created under a high vacuum in the vicinity of a target comprising the chemical elements to be deposited. The active species of the plasma, by bombarding the target, tear off said elements, which are deposited on the substrate, forming the desired thin layer. This process is said to be “reactive” when the layer consists of a material resulting from a chemical reaction between the elements torn from the target and the gas contained in the plasma. The major advantage of this method lies in the possibility of depositing on the same line a very complex stack of layers by successively scrolling the substrate under different targets, generally in one and the same device.

However, the magnetron process has a drawback when the substrate is not heated during deposition: the TCO and titanium oxide layers obtained are weakly crystallized so that their respective properties of emissivity and photocatalytic activity are not optimized. Heat treatment is then necessary.

This heat treatment, intended to improve the crystallization of the TCO and photocatalytic layers, is preferably chosen from quenching, annealing and rapid annealing treatments. The improvement in crystallization can be quantified by an increase in the rate of crystallization (the mass or volume proportion of crystallized material) and / or the size of the crystal grains (or the size of coherent diffraction domains measured by diffraction methods. X-ray or Raman spectroscopy). This improvement in crystallization can also be verified indirectly, by improving the properties of the layer. In the case of a TCO type layer, the emissivity decreases, preferably by at least 5% in relative terms, or even by at least 10% or 15%, as does its light and energy absorption. In the case of titanium dioxide layers, improved crystallization results in an increase in photocatalytic activity. Activity is generally assessed by following the degradation of model pollutants, such as stearic acid or methylene blue.

The quenching or annealing treatment is generally carried out in a furnace, respectively quenching or annealing. The entire substrate is brought to a high temperature, of at least 300 ° C. in the case of annealing, and of at least 500 ° C., or even 600 ° C., in the case of quenching.

The rapid annealing is preferably carried out using a flame, a plasma torch or laser radiation. In this type of process, a relative movement is created between the substrate and the device (flame, laser, plasma torch). Generally, the device is mobile, and the coated substrate scrolls past the device so as to treat its surface. These processes make it possible to bring a high energy density to the coating to be treated in a very short time, thus limiting the diffusion of heat towards the substrate, and therefore the heating of said substrate. The temperature of the substrate is generally at most 100 ° C., or even 50 ° and even 30 ° C. during the treatment. Each point of the thin film is subjected to the rapid annealing treatment for a period generally less than or equal to 1 second, or even 0.5 second.

The rapid annealing heat treatment is preferably carried out using infrared laser radiation. The wavelength of the radiation is preferably in a range ranging from 530 to 1200 nm, or from 600 to 1000 nm, in particular from 700 to 1000 nm, or even from 800 to 1000 nm. Laser diodes are preferably used, for example emitting at a wavelength of the order of 808 nm, 880 nm, 915 or even 940 nm or 980 nm. In the form of diode systems, very high powers can be obtained, making it possible to reach surface powers at the level of the coating to be treated greater than 20kW / cm², even at 30kW / cm².

The laser radiation preferably comes from at least one laser beam forming a line (called “laser line” in the remainder of the text) which simultaneously irradiates all or part of the width of the substrate. This mode is preferred because it avoids the use of expensive displacement systems, generally bulky, and delicate maintenance. The in-line laser beam can in particular be obtained using high power laser diode systems associated with focusing optics. The thickness of the line is preferably between 0.01 and 1 mm. The length of the line is typically between 5 mm and 1 m. The profile of the line can in particular be a Gaussian curve or a square wave. The laser line simultaneously irradiating all or part of the width of the substrate can be made up of a single line (then irradiating the entire width of the substrate), or of several lines, possibly separate. When several lines are used, it is preferable that they are arranged so that the entire surface of the stack is treated. The or each line is preferably disposed perpendicular to the direction of travel of the substrate, or disposed obliquely. The different lines can process the substrate simultaneously, or in a time-shifted manner. The important thing is that the entire surface to be treated is. The substrate can thus be set in motion, in particular in translational movement facing the fixed laser line, generally below, but possibly above, the laser line. This embodiment is particularly valuable for continuous processing. Alternatively, the substrate can be fixed and the laser can be mobile. Preferably, the difference between the respective speeds of the substrate and of the laser is greater than or equal to 1 meter per minute, or even 4 and even 6, 8, 10 or 15 meters per minute, in order to ensure a high processing speed. When the substrate is in motion, in particular in translation, it can be set in motion using any mechanical conveying means, for example using strips, rollers or trays in translation. The conveyor system makes it possible to control and regulate the speed of movement. The laser can also be set in motion to adjust its distance from the substrate, which can be useful especially when the substrate is curved, but not only. Indeed, it is preferable that the laser beam is focused on the coating to be treated so that the latter is located at a distance less than or equal to 1 mm from the focal plane. If the substrate or laser movement system is not sufficiently precise as to the distance between the substrate and the focal plane, it is preferable to be able to adjust the distance between the laser and the substrate. This adjustment can be automatic, in particular regulated by means of a measurement of the distance upstream of the treatment.

The laser radiation device can be integrated into a layer deposition line, for example a cathodic sputtering deposition line assisted by magnetic field (magnetron process), or a chemical vapor deposition (CVD) line, in particular assisted by plasma (PECVD), vacuum or atmospheric pressure (APPECVD).

A subject of the invention is also the use of the glazing according to the invention for reducing the appearance of water condensation (in particular mist or frost) on the surface of said glazing.

Figure 1 illustrates schematically a section of part of the glazing according to the invention. Only the stack placed on face 1 of the glazing and a part of the glass substrate are shown.

Are shown, deposited on the substrate 1, the layer 2 of a transparent electrically conductive oxide, the intermediate layer 3 and the photocatalytic layer 4. The optional layers are the protective layer 5, the neutralization layer or stack 6. and the adhesion layer 7.

The examples which follow illustrate the invention without, however, limiting it.

EXAMPLE 1

This example illustrates an embodiment in which the layers are deposited by CVD (chemical vapor deposition), the TCO being tin oxide doped with fluorine (SnO₂ : F).

Stacks consisting, starting from the substrate, of a silicon oxycarbide neutralization layer (of generic formula SiOC), of refractive index 1.65, of a layer of silicon, are deposited in a known manner on a glass substrate. TCO in tin oxide doped with fluorine, refractive index 1.8, an intermediate layer of silica, index 1.48, and finally a photocatalytic layer of TiO₂, index 2.0. As in all the text, the refractive indices are given for a wavelength of 550 nm.

The substrate used in

<td>leaf</td><td>of</td><td>glass</td><td>clear</td>

<td>marketed</td><td>under</td><td>the</td><td>Mark</td>

<td>plaintiff.</td><td></td><td></td><td></td>

frame of the example is 4 mm thick, SGG Planilux® by the

The sample table, according to the invention below or indicates, for each the layers of geometric thicknesses the stack, (in nm) of each of the energy transmission of the substrate coated with the stack (or direct transmission factor of l solar energy), denoted TE, within the meaning of standard EN 410: 1998, aside the colorimetric coordinates a *, stacking, calculated by taking the illuminant D65 and the reference observer CIE-1931.

b *, in reflection as a reference

<td></td><td>Cl</td><td>C2</td><td> 1</td><td> 2</td>

<td>TiO2 (nm)</td><td> 15</td><td> 15</td><td> 15</td><td> 15</td>

<td>SiO2 (nm)</td><td> 20</td><td> 80</td><td> 50</td><td> 50</td>

<td>SnO2: F (nm)</td><td> 300</td><td> 300</td><td> 300</td><td> 300</td>

<td>SiOC (nm)</td><td> 45</td><td> 45</td><td> 45</td><td> 0</td>

<td></td><td></td><td></td><td></td><td></td>

<td>TE (%)</td><td> 71,5</td><td> 71, 9</td><td> 72,8</td><td> 72,5</td>

<td>at*</td><td></td><td></td><td>LO O 1</td><td> -11,2</td>

<td>b *</td><td></td><td></td><td>1 o kO</td><td> 4,4</td>

Table 1

Comparative Examples C1 and C2 have an intermediate layer whose thickness is not optimized, unlike Examples 1 and 2 according to the invention.

This results, for the examples according to the invention, by a gain in energy transmission of more than 0.5%, or even 1%.

The comparison between Examples 1 and 2 illustrates the effect of the SiOC neutralization layer: the stack of Example 2, which is devoid of it, has a less neutral appearance in reflection, tending to yellow-green.

Triple glazing is produced from substrates C1, C2 and 1. The photocatalytic stack is placed on face 1 of the glazing, while two basemissive stacks based on silver are respectively placed on face 2 and 5.

Table 2 below indicates in each case:

the energy transmission of the glazing (or direct transmission factor of solar energy), denoted TE, the solar factor of the glazing, denoted g.

These two quantities are calculated within the meaning of standard EN 410: 1998.

<td></td><td>Cl</td><td>C2</td><td> 1</td>

<td>TE (%)</td><td> 44, 9</td><td> 45,3</td><td> 45, 8</td>

<td>g (%)</td><td> 52,1</td><td> 52,5</td><td> 53, 1</td>

Table 2

The choice of the thickness of the intermediate layer therefore makes it possible to obtain a very significant gain in solar factor.

EXAMPLE 2

This example illustrates an embodiment in which the layers are deposited by cathodic sputtering (magnetron process), the TCO being ITO (mixed oxide of tin and indium).

Stacks consisting, starting from the substrate, of a neutralization stack consisting of a layer of silicon nitride (S13N4) with a refractive index equal to 2.0 and then of a layer of silicon nitride (S13N4) are deposited on a glass substrate. a layer of silica with a refractive index equal to 1.48, a layer of TCO made of mixed tin and indium oxide (ITO) with a refractive index of 1.8, an intermediate layer of silica (STO2) with a refractive index of 1.48 and finally a photocatalytic layer of TiO2 with a refractive index of 2.5. The substrate coated with its stack undergoes an annealing step after the deposition of the layers. The substrate is the same as that used in the previous examples.

Table 3 below indicates, for each sample, according to the invention or for comparison:

the geometric thicknesses (in nm) of each of the layers of the stack, the energy transmission (or direct transmission factor of solar energy), denoted TE, within the meaning of standard EN 410: 1998, of the substrate coated with 1 'stacking, the colorimetric coordinates a *, b *, in reflection on the stacking side, calculated by taking as reference the illuminant D65 and the reference observer CIE-1931.

<td></td><td>C3</td><td>C4</td><td> 3</td><td> 4</td>

<td>TiCt (nm)</td><td> 12</td><td> 12</td><td> 12</td><td> 12</td>

<td>SiCt (nm)</td><td> 10</td><td> 70</td><td> 40</td><td> 40</td>

<td>ITO (nm)</td><td> 100</td><td> 100</td><td> 100</td><td> 100</td>

<td>SiO2 (nm)</td><td> 11</td><td> 11</td><td> 11</td><td> 0</td>

<td>Si3N₄ (nm)</td><td> 16, 5</td><td> 16, 5</td><td> 16, 5</td><td> 0</td>

<td></td><td></td><td></td><td></td><td></td>

<td>TE (%)</td><td> 76, 3</td><td> 76, 2</td><td> 77, 9</td><td> 77,4</td>

<td>at*</td><td></td><td></td><td> -4,4</td><td> 10, 6</td>

<td>b *</td><td></td><td></td><td> -9, 6</td><td> -20, 6</td>

Table 3

Comparative Examples C3 and C4 have an intermediate layer whose thickness is not optimized, unlike Examples 3 and 4 according to the invention.

This results, for the examples according to the invention, by an energy transmission gain of at least 1%.

The comparison between Examples 3 and 4 illustrates the effect of the ST3N4 / STO2 neutralization stack: the stack of Example 4, which does not have any, has a less neutral appearance in reflection, drawing purple.

Triple glazing is produced from the substrates C3, C4 and 3. The photocatalytic stack is placed on face 1 of the glazing, while two basemissive stacks based on silver are respectively placed on face 2 and 5.

Table 4 below indicates in each case:

the energy transmission of the glazing (or direct transmission factor of solar energy), denoted TE, the solar factor of the glazing, denoted g.

These two quantities are calculated within the meaning of standard EN 410: 1998.

<td></td><td>C3</td><td>C4</td><td> 3</td>

<td>TE (%)</td><td> 47,3</td><td> 47,2</td><td> 48,2</td>

<td>g (%)</td><td> 56, 0</td><td> 55, 8</td><td> 57,0</td>

Table 4

The choice of the thickness of the intermediate layer made according to the invention therefore makes it possible to obtain a very significant gain in solar factor, of at least 1% in absolute value. The use of ITO also makes it possible to increase the solar factor compared to tin oxide doped with fluorine, for a comparable level of emissivity (and therefore anti-condensation).

A very thin protective layer of silicon nitride can be placed between the TCO layer and the intermediate layer, without significant effects on the optical and energy properties of the glazing.

The various glazings exemplified make it possible to greatly reduce the appearance of water condensation, such as mist or frost.