FR3151325A1 - MULTIPLE GLAZING INCLUDING A SOLAR-PROOF COATING AND AN ANTI-REFLECTIVE COATING - Google Patents

Abstract

Multiple glazing with thermal insulation properties incorporating a first coating (12) with antisolar properties and a second coating (13) with antireflective properties in which said first coating is present on face 2 of said first substrate, and in which said second coating (13) is deposited on face 3 of the second substrate (10) and/or is deposited on face 2 of the first substrate between the glass surface and said first coating.

Description

MULTI-GLAZING INCLUDING A SOLAR CONTROL COATING AND AN ANTI-REFLECTIVE COATING

The invention relates to multiple glazing, in particular double or triple glazing for the building sector, said glazing comprising a functional metallic-type layer capable of acting on solar radiation and in particular solar infrared radiation, in particular with a wavelength between 780 nm and 5000 nm.

The invention relates more particularly to multiple glazings with infrared reflective properties, often referred to in the field as anti-solar glazing, and exhibiting a low solar factor.

These windows are therefore intended to be fitted more specifically to buildings, in particular with a view to limiting the amount of solar energy entering them.

In such multiple glazing units, for example double glazing, two glass substrates are held apart by spacers, thus defining a cavity filled with an insulating gas, which can be air, argon, or krypton. Double glazing therefore consists of two panes (substrates) of glass separated by a layer of gas. The sequence 4/16/4 designates a double glazing unit composed of two 4 mm thick panes of glass and a 16 mm air gap, as shown in the diagram. FIG. 1 attached.

Conventionally, the faces of a multi-pane glazing unit are designated from the outside of the building. For example, a double-glazed unit thus has 4 faces, face 1 being on the outside of the building (and therefore constitutes the outer pane of the glazing), face 4 on the inside of the building (and therefore constitutes the inner pane of the glazing), faces 2 and 3 being on the inside of the double glazing unit.

Similarly, triple glazing has 6 panes: pane 1 is on the outside of the building (outer pane), pane 6 is on the inside of the building (inner pane), and panes 2 through 5 are on the inside of the triple glazing, as shown in the diagram. FIG. 2 attached.

As is well known, thermally insulating double glazing units (often also called double glazing (DGU for Double Glazing Unit) or triple glazing (TGU for Triple Glazing Unit)) comprise a stack of layers incorporating at least one functional metallic layer, that is, one with the property of reflecting solar infrared radiation. This includes at least one functional metallic layer based on silver or a silver-containing metallic alloy, and most often a plurality of such metallic layers, for example, two or three silver layers separated by layers of dielectric materials. By infrared reflectivity, it is understood that at least a portion of the solar infrared radiation, preferably the majority, is reflected by the stack via its functional layer(s), without excluding the possibility that another portion may be absorbed by it.

This stack is classically placed on face 2 of the double glazing in such solar control glazing for maximum efficiency.

Examples of multiple glazings equipped with such silver layers are described, for example, in publications WO 2007/101964, EP877005, EP718250, FR2856627, EP 847965, EP 183052, EP226993, EP2920126, EP2766318, EP1441996, EP2432745, EP2424823, EP2332891, EP1730088, EP1663887, EP1606225, EP3041676, US10556824, EP1458653 or EP3004012.

Although the functional metallic layer(s) is/are preferably silver-based, other metallic layers can also be considered without departing from the scope of the invention, in particular those based on precious metals such as Au, Pt, or even on Ni, Cr, NiCr, Nb, Ti, the latter being able to be nitrided.

Currently, such a layer stack is first deposited onto one of the glass substrates of the multi-pane glazing in a single magnetic field-assisted sputtering deposition system. This is achieved using targets made of the material to be deposited, or a metallic target, for example silver, or a constituent element of the layer such as silicon or titanium, in a reactive atmosphere of oxygen or nitrogen, to obtain a final layer of a dielectric material such as silicon dioxide or silicon nitride. In the field, this process is called a "magnetron" deposition process.

One parameter used to measure the quality of multi-pane solar glazing is the solar factor (SF), also known as the g-factor. It is defined as the ratio of the energy entering the room through the glazing to the incident solar energy. It can be calculated by summing the energy flux transmitted directly through the glazing and the energy flux absorbed and then re-emitted inwards by the glazing. The SF(g) coefficient can be measured according to standard EN 410 (2011-04).

Furthermore, in the building industry, glazing with a high level of light transmission (i.e., in the visible spectrum) is sought, but this can vary, particularly from 50 to 85%. To compare the performance of different glazing options, it is therefore common to also consider the glazing's selectivity, that is, its TL/g ratio. A higher selectivity ensures adequate room illumination without excessive heating from incident solar radiation, especially its infrared component.

In countries with high levels of sunshine, it is always necessary to improve the performance of the multiple insulating glazing described above, and in particular their selectivity, for the same level of light transmission.

The object of the present invention is to provide multi-layered solar glazing comprising a stack of layers incorporating at least one functional metallic layer with infrared reflective properties as described above and whose solar factor and consequently selectivity are improved.

To this end, the present invention relates more particularly to a multi-pane glazing with thermal insulation properties, obtained by combining at least two glass substrates separated by a gas layer, the front face of the first substrate defining the outer wall of the glazing, the successive faces of said two substrates being numbered from 1 to 4 from the outside to the inside of said glazing. The multi-pane glazing incorporates a) a first coating with infrared-reflective properties consisting of a stack of layers preferably including at least one silver-based metallic functional layer, and b) a second coating with visible light-reflecting properties consisting of a layer of a material with a refractive index at 550 nm lower than that of the glass, or consisting of a stack of layers, including at least one layer of a material with a refractive index at 550 nm lower than that of the glass, preferably less than 1.4, or even less than 1.35.

In the multiple glazing according to the invention, said first coating is present on face 2 of said first substrate and said second coating is deposited on face 3 of the second substrate and/or is deposited on face 2 of the first substrate between the glass surface and said first coating.

In a novel way, it was found that the combination of these two coatings, one with infrared reflective properties and the other with anti-reflective properties, made it possible to offer multiple glazing options with improved solar factor and selectivity, for the same target light transmission.

It is known that the reflectivity of a transparent glass surface is primarily determined by the difference in refractive index between the surface and that of air (which is equal to 1). To achieve antireflective properties on a reflective surface, a transparent layer (here called an antireflective coating) is deposited. This layer provides specific optical behavior, in which reflected light waves are out of phase with incident light waves when reflection occurs at the air/coating interface and at the coating/glass interface. This type of coating is called a single-layer antireflective coating.

By anti-reflective coating, we describe here any coating capable of reducing the reflection of visible light (i.e., wavelength between 380 and 780 nm) on a glass surface, in particular by at least 1%, or even 2%, or even 3% (i.e., reducing an initial reflection of visible light from 4% to 3, 2 or even 1%).

Light transmission and reflection at the surface of a glass substrate on which such a coating is deposited can be measured according to standard EN 410 (2011-04).

There are various ways to form such coatings, particularly porous silica layers. These layers can be nanoporous, mesoporous, or macroporous.

These coatings are characterized by the presence of a certain amount of air trapped in the porosity. The porosity is created by the imperfect compactness of the nanoparticles, by the removal of porogens such as PMMA beads present within the silica layer and then removed by heating or by acid/alkaline etching. Such coatings are described, for example, in the following publications: Chen et al., Journal of Sol-Gel Science and Technology 19, 77–82, 2000; Kocs et al., Ceramics International 48 (2022) 4165–4171; Zheng et al., Ceramics International 46 (2020) 18623–18631; and Yoo et al., Vol. 9, No. 11 / 1 November 2019 / Optical Materials Express or patent publications WO2013024226 or EP1679291.

• Soit en utilisant un porogène organique sacrificiel qui brule à la trempe, comme indiqué précédemment,
• Soit en utilisant un porogène « durable », du type bille nanométrique creuse et dans un tel cas un traitement thermique n’est pas nécessaire.

Currently, several techniques exist for creating porous layers, particularly through the use of porogens:

• Either by using a sacrificial organic porogen that burns upon quenching, as previously indicated,
• Either by using a "durable" porogen, such as a hollow nanometric bead, in which case heat treatment is not necessary.

Without departing from the scope of the invention, it is also possible to use other anti-reflective coatings than of the porous silica type, in particular acrylates crosslinkable under the action of radiation. Preferably, porosity is not present on the surface for such coatings, the surface is therefore very smooth.

According to another alternative, the invention also uses an antireflective coating consisting of a stack of layers with different refractive indices (generally alternating layers with high and low refractive indices) to achieve a phase shift of the reflected light waves. This type of product is called a multilayer or interference antireflective coating. These coatings are generally developed to achieve high-performance antireflective properties over a wider range of wavelengths. An example is given in publication WO2012069767.

For the purposes of this invention, "stacking" means a set of at least two superimposed layers, starting from the surface of a glass substrate.

In particular, for the first infrared-reflecting stack comprising at least one metallic functional layer, stacks leading to a normal emissivity _εn less than or equal to 0.2, preferably less than or equal to 0.1, preferably even less than or equal to 0.08, or even very advantageously less than or equal to 0.05, in the sense of standard EN12898 (2001-07).

By "in contact" we mean, in the context of the invention, that no other intermediate layer is interposed between the two layers mentioned.

• ledit deuxième revêtement est constitué par une unique couche comprenant de l’oxyde de silicium d’indice de réfraction inférieur à 1,40 à 550 nm, de préférence d’indice de réfraction inférieur à 1,35 à 550 nm,
• ladite couche comprend de l’oxyde de silicium poreux, en particulier nanoporeux, mésoporeux ou macroporeux,
• l’épaisseur physique de ladite couche unique présente sur la face 3 est comprise entre 90 nm et 150 nm,
• l’épaisseur de ladite couche unique présente sur la face 2 est comprise entre 90 nm et 400 nm,
• la transmission lumineuse du vitrage est comprise entre 45 et 85%, de préférence entre 60 et 80%,
• ledit deuxième revêtement à propriété anti-reflet est déposé sur la face 3 du deuxième substrat,
• ledit deuxième revêtement à propriété anti-reflet est déposé sur la face 2 du premier substrat, entre la surface de verre et ledit premier revêtement.
• selon un premier mode, le vitrage ne comprend qu’un seul revêtement à propriété anti-reflet,
• selon un autre mode, le vitrage comprend un revêtement à propriété anti-reflet déposé sur la face 3 du deuxième substrat et un revêtement à propriété anti-reflet déposé sur la face 2 du premier substrat, entre la surface de verre et ledit premier revêtement
• d’autres revêtements à propriétés antireflet, en particulier constituées d’empilements dits interférentiels, peuvent être incorporés sur les faces externes du vitrage (c'est-à-dire en face 1 et/ou 4 d’un DGU et en face 1 et 6 du TGU).

According to preferred embodiments of such multiple glazings, which can of course be combined with each other, where appropriate:

• said second coating consists of a single layer comprising silicon oxide with a refractive index of less than 1.40 at 550 nm, preferably with a refractive index of less than 1.35 at 550 nm,
• said layer comprises porous silicon oxide, in particular nanoporous, mesoporous or macroporous,
• The physical thickness of said single layer present on face 3 is between 90 nm and 150 nm.
• The thickness of said single layer present on face 2 is between 90 nm and 400 nm.
• The light transmission of the glazing is between 45 and 85%, preferably between 60 and 80%.
• said second anti-reflective coating is deposited on face 3 of the second substrate,
• said second coating with anti-reflective properties is deposited on face 2 of the first substrate, between the glass surface and said first coating.
• According to the first method, the glazing comprises only a single coating with anti-reflective properties.
• In another method, the glazing comprises an anti-reflective coating deposited on face 3 of the second substrate and an anti-reflective coating deposited on face 2 of the first substrate, between the glass surface and said first coating
• other coatings with anti-reflective properties, in particular made up of so-called interference stacks, can be incorporated on the external faces of the glazing (i.e. on face 1 and/or 4 of a DGU and on face 1 and 6 of the TGU).

The invention relates in particular to a double glazing obtained by the association of two glass substrates separated by a gas layer, in which said first coating is present on face 2 of said first substrate, and in which said second coating is deposited on face 3 of the second substrate and/or is deposited on face 2 of the first substrate between the glass surface and said first coating.

According to specific and advantageous methods of such double glazing:

- said first coating is present on face 2 of said first substrate, and a single second coating is deposited on face 3 of the second substrate,

- said first coating is present on face 2 of said first substrate and a single second coating is deposited on face 2 of the second substrate, between the glass surface and said first coating,

- said first coating is present on face 2 of said first substrate, a first second coating is deposited on face 3 of the second substrate and a second second coating is deposited on face 2 of the first substrate between the glass surface and said first coating.

The invention also relates to a triple glazing with thermal insulation properties, obtained by the association of three glass substrates separated by gas layers, the first substrate delimiting faces 1 and 2 of the glazing, the second substrate delimiting faces 3 and 4 of the glazing, said third substrate delimiting faces 5 and 6 of the glazing, in which said first coating is present on face 2 of said first substrate, and in which said second coating is and/or deposited on face 3 of the second substrate, on face 4 of the second substrate and/or is deposited on face 2 of the first substrate between the glass surface and said first coating.

According to specific and advantageous methods of such triple glazing:

- a single second coating is deposited on face 3 of the second substrate and/or is deposited on face 2 of the first substrate between the glass surface and said first coating,

- a first second coating is deposited on face 3 of the second substrate and a second second coating is deposited on face 2 of the first substrate between the glass surface and said first coating,

- a first second coating is deposited on face 3 of the second substrate and a second second coating is deposited on face 4 of said second substrate.

• LaFIG. 1décrit un double vitrage selon une première réalisation de l’invention,
• LaFIG. 2décrit un triple vitrage selon une seconde réalisation de l’invention.

The advantageous details and features of the invention become apparent from the following non-limiting examples, illustrated with the aid of the attached figures which schematically depict different embodiments of multiple glazing according to the present invention:

• There FIG. 1 describes a double glazing system according to a first embodiment of the invention.
• There FIG. 2 describes triple glazing according to a second embodiment of the invention.

In these figures, the actual dimensions and proportions of the various constituent elements of the glazing are obviously not respected in order to facilitate their reading.

There FIG. 1 represents a double glazing 100 (DGU) of classic design consisting of two sheets of glass, each constituting a glass substrate 10, 30. The two substrates are separated, held together and opposite each other by spacers 21 and frames 20, the whole delimiting an enclosed space filled by an intermediate gas layer 15. According to the invention, the gas can be air, argon or Krypton (or a mixture of these gases).

The first pane of glass (substrate 30) faces outwards when considering the direction of sunlight entering the building, illustrated by the arrow pointing from left to right in the figure. Its front face 29 (referred to as "face 1"), which also forms the outer wall of the double glazing 100, can be bare or alternatively coated with a self-cleaning coating as described in publication EP 850204 or an anti-condensation coating as described in publications WO2007/115796 or WO2009/106864.

The substrate 30 is coated on its rear face 31 (face 2 of the DGU), facing the intermediate gas layer 15, with a coating 12 called antisolar because it reflects a major part of the infrared portion of the incident radiation, in particular from 780 nanometers to 5000 nanometers. This stacking is of the type described previously, and preferably comprises at least one silver layer, preferably two or three silver layers.

The other sheet of glass, oriented furthest inside the building when considering the direction of the sunlight entering it, constitutes the second substrate 10. According to the invention and as shown in the FIG. 1 , this substrate 10 is coated on its front face 9 (face 3 of the DGU), facing the intermediate gas blade, with an anti-reflective coating 13 of the type previously described and in particular consisting of a layer of porous silicon oxide, with a refractive index at 550 nm lower than that of glass, in particular on the order of 1.33. On the FIG. 1 , we have represented the anti-reflective coating 13 on face 3 of the DGU but according to the invention it is also possible to place this on face 2 of the DGU, in particular between the surface 31 of the substrate 30 and the anti-solar stack 12.

According to another embodiment of the present invention, it is advantageous to arrange two coatings with anti-solar function in the way previously described respectively on faces 2 and 3 of the DGU, as described in the examples that follow.

There FIG. 2 This time represents a triple glazing unit 101 (TGU) of classic design consisting of three panes of glass, each constituting a glass substrate 30, 10 and 40. Identical numbers are taken from the FIG. 1 to illustrate the same constituent elements.

As before, the substrate 30 is coated on its rear face 31 (face 2 of the DGU), facing the intermediate gas blade 15, by a coating 12 called antisolar.

According to an embodiment of the invention illustrated by the FIG. 2 The intermediate glass sheet 10 is coated on its front face 9 (face 3 of the DGU), facing the intermediate gas layer, with an anti-reflective coating 13 of the type described above, in particular consisting of a layer of porous silicon oxide. Another anti-reflective coating 13' can also be deposited on the other face 11 of the intermediate substrate 10 (i.e., on face 4) of the TGU. According to the invention, it is also possible to place this coating on face 2 of the TGU, in particular between the surface 31 of the substrate 30 and the anti-solar stack 12, or even on faces 2 and 4 of the DGU or 3 and 4 of the TGU.

The invention and its advantages will be better understood by reading the following non-limiting examples.

In all the examples below, the stacks of low-emissivity thin films are deposited on clear soda-lime glass substrates, marketed under the reference PLANICLEAR® by the filing company .

For all the examples below, for double-glazed or triple-glazed units, the thin-film layers have been positioned on faces 2 and/or 3 respectively, with the numbering increasing from the outermost glass substrate when considering the direction of sunlight entering the building. Face 1 therefore corresponds to the glass surface facing outwards. The double and triple glazing units described in the examples below conform to Figures 1 and 2.

The double glazing units (or DGU for Double Glazing Unit) assembled according to the examples have the configuration: 4-16-(Ar 90%)-4, that is to say that they consist of two sheets of transparent Planiclear® glass of 4 mm separated by an intermediate gas layer comprising 90% argon and 10% air by volume, with a thickness of 16 mm, all held together by a frame structure 20 and spacers 21.

Triple glazing units (or TGU or DGU for Double Glazing Unit) assembled according to the examples have the following configuration: 4-16-(Ar 90%)-4-16-(Ar 90%)-4.

Table 1 below summarizes the general magnetron sputtering deposition conditions for obtaining the different layers used in the antisolar stacks of the examples:

Layer Target employee Deposition pressure Gas If ₃ N ₄ Si:Al at 92.8% by weight 1.5 x ^10⁻³ mbar Ar /(Ar + _N2 ) at 45% _TiO2 TiO _x with x on the order of 1.9 1.5 x ^10⁻³ mbar Ar/(Ar + _O2 ) at 95% SnZnO SnZn:Sb at 34:65:1 weight 2.10 ^-3 mbar Ar/(Ar + _O2 ) at 58% ZnO Zn:Al at 98:2% by weight 2.10 ^-3 mbar Ar/(Ar + _O2 ) at 52% Ti Metallic titanium 2.10 ^-3 mbar 100% Ar Ag Ag 4.10 ^-3 mbar 100% Ar _SiO2 Si:Al at 92.8% by weight 2.10 ^-3 mbar Ar/(Ar + _O2 ) at 70%

The anti-reflective coating consists of a single layer based on porous silicon oxide whose porosity is adjusted to obtain a layer of material with a refractive index of 1.33 at 550 nm.

Example 1:

In this first series of examples, we compare DGU double glazing units with a target light transmission of 68.5%.

The double glazing has a 4/16/4 configuration as described previously.

This first example illustrates the case of a combination of an anti-solar coating deposited on face 2 by magnetron sputtering and the anti-reflective layer of porous silica described previously (index 1.33) on face 2 or on face 3 or on both faces.

More specifically, the glazing according to example 1a is a reference glazing with a light transmission of 68.5% and comprising on its face 2 an antisolar stack comprising two functional silver layers and whose complete structure is described in Table 3 below.

In example 1b, a single anti-reflective layer of porous silica is positioned on face 2 of the DGU, between the glass surface and the anti-solar stack, with a thickness of 115 nm and a refractive index of 1.33 at 550 nm.

The antisolar stacking is then adjusted to obtain a light transmission of 68.5% (in particular by modifying the thicknesses of the silver layers), as described in Table 3 below.

In example 1c, two anti-reflective layers with the same index as before are positioned on faces 2 and 3 of the DGU, with thicknesses of 103.5 nm and 100 nm respectively. The anti-solar stacking (in particular the thicknesses of the silver layers) is then adjusted to obtain a final light transmission of 68.5% respectively.

The results are shown in Table 2 below:

Ex.1a Ex.1b Ex.1c Solar factor (g) 36.4 34.5 33.8 Selectivity 1.88 1.98 2.01 T _L 68.5 68.5 68.5 a* _T -4.8 -4.8 -4.5 b* _T 0.6 0.9 2.1 T _E 34.8 33.0 33.0 RL _ext 16.0 16.0 16.0 RL _int 15.0 15.0 14.7

In the previous table, T _L is the light transmission, a* _T and b* _T are the colorimetric coordinates in the international Lab system, T _E is the energy transmission and RL _ext and RL _int are the light reflections respectively on the outside and inside side of the double glazing.

The thicknesses in nanometers of the different layers constituting the antisolar stacks for examples 1a to 1c are given in Table 3 below (the one furthest from the surface of the glass substrate being referenced first):

Ex.1a Ex.1b Ex.1c SnZnO 1.0 1.0 1.0 If ₃ N ₄ 32.8 31.1 30.9 SnZnO 5.0 5.0 5.0 ZnO 5.0 5.0 5.0 Ti 0.4 0.4 0.4 Ag 15.5 16.8 17.0 ZnO 5.0 5.0 5.0 If ₃ N ₄ 82.2 84.1 85.4 ZnO 5.0 5.0 5.0 Ti 0.6 0.6 0.4 Ag 15.5 17.3 18.2 ZnO 5.0 5.0 5.0 _TiO2 19.2 20.9 21.5

We can see from the comparison of the examples above that the selectivity obtained in the case of an anti-solar stack deposited on face 2 is significantly improved by the addition of an anti-reflective layer on face 2 and/or face 3 of the double glazing.

In particular, the application of the antireflective coating to face 2 and/or 3, and the corresponding adjustment of the antisolar stacking structure, results in a significant decrease in the solar factor g and consequently a significant improvement in selectivity. For example, for the same T _{_L} of 68.5%, the addition of the antireflective coating to face 2 and the adjustment of the antisolar stacking leads to a 5.2% decrease in the g factor (comparison of examples 1a and 1b). The gain can be even more significant (a 7.1% decrease in g) if two antireflective stacks, on faces 2 and 3, are combined with the antisolar stacking within the DGU (comparison of examples 2a and 2c).

Example 2:

In this second series of examples, we compare DGU double glazing units with a target light transmission of 77%.

Like the previous one, this example illustrates the case of a combination of an anti-solar coating deposited on face 2 by magnetron sputtering and the anti-reflective layer described previously (index 1.33) on face 2 or on face 3 or both faces.

More specifically, the glazing according to example 2a is a reference glazing with a higher light transmission of 77% and comprising on its face 2 an antisolar stack comprising two functional silver layers and whose complete structure is described in Table 5 below.

In example 2b, a porous silica anti-reflective monolayer is positioned directly on face 3 of the DGU, with a thickness of 106 nm and a refractive index of 1.33 at 550 nm.

In example 2c, two anti-reflective layers with the same index as before are positioned on faces 2 and 3 of the DGU, with thicknesses of 103.5 nm and 100 nm respectively. The anti-solar stacking (in particular the thicknesses of the silver layers) is then adjusted to obtain a final transmission of 77.0% respectively.

The results are shown in Table 4 below:

Ex. 2a Ex. 2b Ex.2c Solar factor (g) 45.9 42.5 40.7 Selectivity 1.68 1.81 1.89 T _L 77.0 77.0 77.0 a* _T -3.3 -3.1 -4.0 b* _T 0.7 0.8 0.5 T _E 43.9 40.7 39.0 RL _ext 10.8 10.3 9.9 RL _int 11.3 10.4 9.9

The thicknesses in nanometers of the different layers constituting the antisolar stacks for examples 2a to 2c are given in Table 5 below (the one furthest from the surface of the glass substrate being referenced first):

Ex. 2a Ex. 2b Ex.2c SnZnO 1.0 1.0 1.0 If ₃ N ₄ 33.0 29.4 32.3 SnZnO 5.0 5.0 5.0 ZnO 5.0 5.0 5.0 Ti 0.4 0.4 0.4 Ag 15.1 17.3 15.5 ZnO 5.0 5.0 5.0 If ₃ N ₄ 84.2 83.2 81.3 ZnO 5.0 5.0 5.0 Ti 0.6 0.2 0.2 Ag 9.4 11.3 14.7 ZnO 5.0 5.0 5.0 _TiO2 25.1 23.9 21.5

We can see from the comparison of the examples above that the selectivity obtained in the case of an anti-solar stack deposited on face 2 is significantly improved by the addition of an anti-reflective layer on face 2 and/or face 3 of the double glazing.

In particular, the application of the antireflective coating to face 2 and/or 3, and the corresponding adjustment of the antisolar stacking structure, results in a significant decrease in the solar factor g and consequently a significant improvement in selectivity. For example, for the same T _{_L} of 77%, the addition of the antireflective coating to face 3 and the adjustment of the antisolar stacking leads to a 7.4% decrease in the g factor (comparison of examples 2a and 2b). The gain can be even more significant (11.3% decrease in g) if two antireflective stacks, on faces 2 and 3, are combined with the antisolar stacking within the DGU (comparison of examples 2a and 2c).

Example 3:

In this third set of examples, we describe TGU triple glazing units with a target light transmission of 68.5%. These triple glazing units have a 4/16/4/16/4 configuration, as described previously.

More specifically, the glazing according to example 3a is a reference TGU comprising on its face 2 an antisolar stack comprising two functional silver layers and whose complete structure is described in table 7 below.

In example 3b, an additional 95 nm thick anti-reflective layer of porous silica with a refractive index of 1.33 is positioned on face 3 of the TGU. The stacking (in particular the thicknesses of the silver layers) is then adjusted to obtain the target light transmission of 68.5%.

In example 3c, the two anti-reflective porous silica layers with a refractive index of 1.33 are positioned on faces 2 and 3 of the TGU respectively, with thicknesses of 332 nm and 99 nm respectively.

The anti-solar stacking (in particular the thicknesses of the silver layers) is adjusted to achieve a final target light transmission of 68.5.

The results are shown in Table 6 below:

Ex.3a Ex.3b Ex.3c Solar factor (g) 39.5 37.9 35.7 Selectivity 1.73 1.81 1.92 T _L 68.5 68.5 68.5 a* _T -3.6 -5.0 -5.0 b* _T -0.5 0.7 -4.8 T _E 37.0 35.6 1.5 RL _ext 16.0 16.0 16.0 RL _int 18.3 17.1 17.5

The thicknesses in nanometers of the different layers constituting the antisolar stacks for examples 3a to 3c are given in Table 7 below (the one furthest from the surface of the glass substrate being referenced first):

Ex.3a Ex.3b Ex.3c SnZnO 1.0 1.0 1.0 If ₃ N ₄ 30.8 33.5 29.1 SnZnO 5.0 5.0 5.0 ZnO 5.0 5.0 5.0 Ti 0.5 0.4 0.4 Ag 15.3 14.8 16.9 ZnO 5.0 5.0 5.0 If ₃ N ₄ 80.1 82.2 82.3 ZnO 5.0 5.0 5.0 Ti 0.2 0.4 0.2 Ag 11.7 14.1 15.3 ZnO 5.0 5.0 5.0 _TiO2 20.3 20.7 21.5

4*/16 /4

It is also observed that, for the same TL of 68.5%, adding the antireflective layer on face 3 and adjusting the antisolar stacking results in a 5% reduction in the g factor (comparison of examples 2a and 2b). The gain can be even more significant (a 9.5% reduction in g) if two antireflective stacks, on faces 2 and 3 respectively, are combined with the antisolar stacking within the TGU (comparison of examples 3a and 3c).

Claims (18)

Multiple glazing with thermal insulation properties, obtained by combining at least two glass substrates (10, 30) separated by a gas layer (15), the front face (29) of the first substrate (30) defining the outer wall of the glazing, the successive faces of said two substrates being numbered from 1 to 4 from the outside to the inside of said glazing,
said multi-glazing incorporating:

• a first coating (12) with infrared reflecting properties consisting of a stack of layers, said stack preferably comprising at least one silver-based metallic layer,
• a second coating (13) with anti-reflective properties consisting of a layer of a material with a refractive index at 550 nm lower than that of glass or consisting of a stack of layers, including at least one layer of a material with a refractive index at 550 nm lower than that of glass,

in which said first coating is present on face 2 of said first substrate, and
in which said second coating (13) is deposited on face 3 of the second substrate (10) and/or is deposited on face 2 of the first substrate, between the glass surface and said first coating. Multiple glazing according to claim 1, wherein said second coating consists of a single layer comprising silicon oxide having a refractive index of less than 1.40 at 550 nm, preferably with a refractive index of less than 1.35 at 550 nm. Multiple glazing according to the preceding claim, wherein said layer comprises porous silicon oxide, in particular nanoporous, mesoporous or macroporous. Multiple glazing according to any one of the preceding claims in which the physical thickness of said single layer present on face 3 is between 90 nm and 150 nm. Multiple glazing according to any one of the preceding claims wherein the thickness of said single layer present on face 2 is between 90 nm and 400 nm. Multiple glazing according to any one of the preceding claims, wherein the light transmission is between 45 and 85%, preferably between 60 and 80%. Multiple glazing according to any one of the preceding claims, wherein said second coating with anti-reflective properties is deposited on face 3 of the second substrate. Multiple glazing according to any one of the preceding claims, wherein said second coating with anti-reflective properties is deposited on face 2 of the first substrate, between the glass surface and said first coating. Multiple glazing according to one of the preceding claims, comprising only one coating with anti-reflective properties. Multiple glazing according to any one of claims 1 to 8, wherein an anti-reflective coating is deposited on face 3 of the second substrate and an anti-reflective coating is deposited on face 2 of the first substrate, between the glass surface and said first coating Double glazing according to any one of the preceding claims, obtained by combining two glass substrates (10, 30) separated by a gas layer (15), wherein said first coating is present on face 2 of said first substrate, and wherein said second coating (13) is deposited on face 3 of the second substrate (10) and/or is deposited on face 2 of the first substrate between the glass surface and said first coating. Double glazing according to the preceding claim, wherein said first coating is present on face 2 of said first substrate (30), and wherein a single second coating (13) is deposited on face 3 of the second substrate (10). Double glazing according to claim 11, wherein said first coating is present on face 2 of said first substrate (30) and wherein a single second coating (13) is deposited on face 2 of the second substrate (10), between the glass surface and said first coating. Double glazing according to claim 11, wherein said first coating is present on face 2 of said first substrate, and wherein a first second coating (13) is deposited on face 3 of the second substrate (10) and wherein a second second coating (13) is deposited on face 2 of the first substrate between the glass surface and said first coating. Triple glazing with thermal insulation properties according to any one of claims 1 to 10, obtained by combining three glass substrates separated by gas layers, the first substrate delimiting faces 1 and 2 of the glazing, the second substrate delimiting faces 3 and 4 of the glazing, said third substrate delimiting faces 5 and 6 of the glazing, in which said first coating is present on face 2 of said first substrate, and in which said second coating (13) and/or is deposited on face 3 of the second substrate (10), on face 4 of the second substrate and/or is deposited on face 2 of the first substrate between the glass surface and said first coating. Triple glazing according to any one of the preceding claims, wherein a single second coating (13) is deposited on face 3 of the second substrate (10) and/or is deposited on face 2 of the first substrate between the glass surface and said first coating. Triple glazing according to claim 15, wherein a first second coating (13) is deposited on face 3 of the second substrate (10) and wherein a second second coating (13’) is deposited on face 2 of the first substrate between the glass surface and said first coating. Triple glazing according to claim 15, in which a first second coating (13) is deposited on face 3 of the second substrate (10) and in which a second second coating (13’) is deposited on face 4 of said second substrate (10).