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

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

The invention relates to multiple glazing, in particular double glazing or triple glazing for the building sector, said glazing comprising a functional layer of metallic type 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 reflection properties, often called in the field antisolar glazings, and having a low solar factor.

These glazings are therefore intended to equip buildings in particular, in particular with a view to limiting the solar energy input entering them.

In such multiple glazings, for example double glazing, two glass substrates are held at a distance by spacers, so as to delimit a cavity filled with an insulating gas which can be air, argon or Krypton. Double glazing is therefore made up of two sheets (substrates) of glass separated by a gas layer. The sequence 4/16/4 thus designates a double glazing composed of two sheets of glass 4 mm thick and a 16 mm air layer as shown in the attached.

Conventionally, the faces of a multiple glazing unit are designated from the outside of the building. For example, a double glazing unit has 4 faces, face 1 being on the outside of the building (and therefore constitutes the external wall of the glazing), face 4 on the inside of the building (and therefore constitutes the internal wall of the glazing), faces 2 and 3 being on the inside of the double glazing unit.

Similarly, a triple glazing unit has 6 faces, face 1 is on the outside of the building (outer wall of the glazing), face 6 is on the inside of the building (inner wall of the glazing) and faces 2 to 5 are on the inside of the triple glazing, as shown in the attached.

As is known, thermally insulating double glazing (often also called double glazing (DGU for Double Glazing Unit according to the English term) or triple glazing TGU (for Triple Glazing Unit)) comprises a stack of layers incorporating at least one functional metal layer, i.e. with a solar infrared reflection property, in particular at least one metallic functional layer based on silver or a metal alloy containing silver, and most often a plurality of such metallic layers, for example 2 or 3 silver layers separated by layers of dielectric materials. By infrared reflection property, it is meant that at least a portion of the solar infrared radiation, preferably the major portion, is reflected by the stack via its functional layer(s), without excluding another portion being absorbed by it.

This stack is traditionally placed on face 2 of the double glazing in such anti-solar glazing for maximum efficiency.

Examples of multiple glazings equipped with such silver layers are for example described 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 metal layer(s) is (are) preferably silver-based, other metal layers can also be envisaged without departing from the scope of the invention, in particular based on precious metals such as Au, Pt, or even based on Ni, Cr, NiCr, Nb, Ti, the latter being able to be nitrided.

Currently, such a stack of layers is previously deposited on one of the glass substrates of the multiple glazing in the same installation for depositing layers by magnetic field-assisted cathode sputtering from targets made of the material to be deposited or from a metal 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 oxide or silicon nitride. Such a process is called in the field of “magnetron” deposition process.

A parameter for measuring the quality of multiple glazing with an antisolar function is the solar factor FS or g factor. It is defined as the ratio between the energy entering the room through the glazing and the incident solar energy. It can be calculated by the sum of the energy flow transmitted directly through the glazing and the energy flow absorbed and then re-emitted to the interior by the glazing. The FS coefficient (g) can be measured according to standard EN 410 (2011-04).

In addition, in the construction industry, glazing is sought with a high level of light transmission (i.e. in the visible range) but which can be variable, in particular from 50 to 85%. In order to be able to compare the performance of different glazings, it is therefore common to also refer to the selectivity of the glazing in question, i.e. its TL/g ratio. Thus, better (greater) selectivity makes it possible to check the good illumination of the room, without excessive heating of the latter under the effect of incident solar radiation, in particular its infrared portion.

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 multiple anti-solar glazings comprising a stack of layers incorporating at least one functional metal layer with infrared reflection properties as described above and whose solar factor and consequently selectivity are improved.

For this purpose, the present invention relates more particularly to a multiple 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 multiple glazing incorporates a) a first coating with infrared reflection properties consisting of a stack of layers preferably comprising at least one silver-based metallic functional layer and b) a second coating with visible light anti-reflection 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 unique way, it was found that the combination of these two coatings, one with infrared reflection properties and the other with anti-reflective properties, made it possible to offer multiple glazings with improved solar factor and selectivity, for the same target light transmission.

It is known that the level of reflection of a transparent glass surface is mainly determined by the contrast of the refractive index existing between the surface and that of air (equal to 1). To obtain antireflective properties from a reflective surface, it is also known to deposit a transparent layer (herein called antireflective coating or with antireflective property) which provides a specific optical behavior, in which the reflected light waves are in phase opposition with the incident waves when the reflection occurs on the air/coating interface and on the coating/glass interface. This type of coating is called single-layer antireflective coating.

By anti-reflective coating, we mean any coating capable of reducing the reflection of visible light (i.e. of 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%).

The light transmission and reflection on 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 different possibilities for forming such coatings, in particular porous silica layers. These layers can be nanoporous, mesoporous or even 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 elimination of porogens such as PMMA beads present within the silica layer and then eliminated by heating or by acid/alkaline attack. 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 or 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.

There are currently several techniques for having porous layers, in particular through the use of porogens:

• Either by using a sacrificial organic porogen that burns on 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 anti-reflective layers other than the porous silica type, in particular acrylates which can be crosslinked under the action of radiation. Preferably, the porosity is not present on the surface for such coatings, the surface is therefore very smooth.

Alternatively, it is also possible to use an antireflection coating according to the invention consisting of a stack of layers of different refractive indices (generally an alternation of layers of high/low refractive indices) in order to obtain a phase shift of the reflected light waves. This type of product is called a multilayer or interference antireflection coating. These coatings are generally developed to obtain very high-performance antireflection properties over a wider range of wavelengths. An example of this is given by publication WO2012069767.

By “stacking” in the sense of the present invention, it is necessary to understand a set of at least two superimposed layers, 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 ε _n less than or equal to 0.2, preferably less than or equal to 0.1, more preferably less than or equal to 0.08, or even very advantageously less than or equal to 0.05, within the meaning of standard EN12898 (2001-07) will advantageously be chosen.

For the purposes of the invention, “in contact” means 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, if necessary:

• 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 coating with anti-reflective property is deposited on face 3 of the second substrate,
• said second coating with anti-reflective property is deposited on face 2 of the first substrate, between the glass surface and said first coating.
• according to a first mode, the glazing comprises only one coating with anti-reflective properties,
• according to another embodiment, the glazing comprises a coating with anti-reflective properties deposited on face 3 of the second substrate and a coating with anti-reflective properties deposited on face 2 of the first substrate, between the glass surface and said first coating.
• other coatings with anti-reflective properties, in particular consisting 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 faces 1 and 6 of the TGU).

The invention relates in particular to double glazing obtained by combining 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 particular and advantageous modes 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 triple glazing with thermal insulation properties, obtained by combining three glass substrates separated by gas blades, 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 and/or is 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 particular and advantageous modes 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.

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

The details and advantageous characteristics of the invention emerge from the following non-limiting examples, illustrated using the attached figures which schematize different embodiments of multiple glazing according to the present invention:

• There describes double glazing according to a first embodiment of the invention,
• There 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 represents a double glazing unit 100 (DGU) of conventional design consisting of two sheets of glass, each constituting a glass substrate 10, 30. The two substrates are separated, held together and facing each other by spacers 21 and frames 20, the assembly delimiting an enclosed space filled by an intermediate gas layer 15. According to the invention, the gas may be air, argon or Krypton (or a mixture of these gases).

The first glass sheet (substrate 30) faces outwards when considering the incident direction of the sunlight entering the building, illustrated by the arrow oriented in the figure from left to right. Its front face 29 (called “face 1”), which also constitutes the outer wall of the double glazing 100, may be bare or alternatively be coated with another coating of the self-cleaning type as described in publication EP 850204 or of the anti-condensation type, 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 blade 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 stack is of the type described above, and preferably comprises at least one layer of silver, preferably two or three layers of silver.

The other sheet of glass, oriented furthest towards the interior of the building when considering the incident direction of the sunlight entering it, constitutes the second substrate 10. According to the invention and as shown in the , this substrate 10 is coated on its front face 9 (face 3 of the DGU), facing the intermediate gas blade, with an antireflection 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 of the order of 1.33. On the , the anti-reflective coating 13 has been shown on the face 3 of the DGU but according to the invention it is also possible to arrange it on the 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 an anti-solar function in the manner previously described respectively on faces 2 and 3 of the DGU, as described in the examples which follow.

There This time represents a triple glazing 101 (TGU) of classic design consisting of three sheets of glass, each constituting a glass substrate 30, 10 and 40. Identical numbers are taken from the to illustrate the same building blocks.

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

According to an embodiment of the invention illustrated by the , the intermediate glass sheet 10 is coated on its front face 9 (face 3 of the DGU), facing the intermediate gas blade, with an antireflection coating 13 of the type previously described and in particular consisting of a layer of porous silicon oxide. Another antireflection 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 arrange it on face 2 of the TGU, in particular between surface 31 of the substrate 30 and the antisolar 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 non-limiting examples which follow.

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

For all the examples below, for double-glazed or triple-glazed assemblies, the thin-film stacks were positioned respectively on face 2 and/or 3, the numbering increasing from the glass substrate furthest to the outside of the building when considering the incident direction of the sunlight entering the building, face 1 therefore corresponding to the glass surface facing the outside of the glazing. The double and triple glazing described in the examples below are in accordance with figures 1 and 2 attached.

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 they are made up of two transparent 4 mm Planiclear® glass sheets separated by an intermediate gas layer comprising 90% argon and 10% air by volume, with a thickness of 16 mm, the whole being held together by a frame structure 20 and spacers 21.

The triple glazing (or TGU or DGU for Double Glazing Unit) assembled according to the examples has the configuration: 4-16-(Ar 90%)-4-16-(Ar 90%)-4.

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

Layer Target used Deposit pressure Gas If ₃ N ₄ Si:Al at 92:8 wt% 1.5.10 ^-3 mbar Ar /(Ar + N ₂ ) at 45% TiO ₂ TiO _x with x of the order of 1.9 1.5.10 ^-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% wt. 2.10 ^-3 mbar Ar /(Ar + O ₂ ) at 52% You Ti metal 2.10 ^-3 mbar Ar at 100% Ag Ag 4.10 ^-3 mbar Ar at 100% SiO ₂ Si:Al at 92:8 wt% 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 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 porous silica anti-reflective layer described previously (index 1.33) on face 2 or on face 3 or on both faces.

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

In example 1b, an antireflective monolayer of porous silica is positioned on face 2 of the DGU, between the glass surface and the antisolar stack, with a thickness of 115 nm and a refractive index of 1.33 at 550 nm.

The antisolar stack 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 of the same index as previously are positioned on faces 2 and 3 of the DGU, with thicknesses of 103.5 nm and 100 nm respectively. The anti-solar stack (in particular the thicknesses of the silver layers) is then adjusted to obtain a final light transmission of 68.5% respectively.

The results are reported 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 exterior and interior sides 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 You 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 You 0.6 0.6 0.4 Ag 15.5 17.3 18.2 ZnO 5.0 5.0 5.0 TiO ₂ 19.2 20.9 21.5

It can be seen by comparing the above examples 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 deposition of the antireflection layer on face 2 and/or 3 and the adjustment accordingly of the structure of the antisolar stack results in a significant reduction in the solar factor g and consequently in a significant improvement in the selectivity. For example, it can be observed that, for the same T _L of 68.5%, the addition of the antireflection layer on face 2 and the adjustment of the antisolar stack results in a 5.2% reduction in the g factor (comparison of examples 1a and 1b). The gain can be even more significant (7.1% reduction in g) if two antireflection stacks, on faces 2 and 3, are combined with the antisolar stack within the DGU (comparison of examples 2a and 2c).

Example 2:

In this second series of examples, we compare DGU double glazing 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 on both faces.

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

In example 2b, an antireflective monolayer of porous silica 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 antireflective layers of the same index as previously are positioned on faces 2 and 3 of the DGU, with thicknesses of 103.5 nm and 100 nm respectively. The anti-solar stack (in particular the thicknesses of the silver layers) is then adjusted to obtain a final transmission of 77.0% respectively.

The results are reported 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 You 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 You 0.6 0.2 0.2 Ag 9.4 11.3 14.7 ZnO 5.0 5.0 5.0 TiO ₂ 25.1 23.9 21.5

It can be seen by comparing the above examples 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 deposition of the antireflection layer on face 2 and/or 3 and the adjustment accordingly of the structure of the antisolar stack results in a significant reduction in the solar factor g and consequently in a significant improvement in the selectivity. For example, it can be observed that, for the same T _L of 77%, the addition of the antireflection layer on face 3 and the adjustment of the antisolar stack results in a reduction of 7.4% in the factor g (comparison of examples 2a and 2b). The gain can be even more significant (reduction of g by 11.3%) if two antireflection stacks, on faces 2 and 3, are combined with the antisolar stack within the DGU (comparison of examples 2a and 2c).

Example 3:

In this third series of examples, TGU triple glazing units with a target light transmission of 68.5% are described. The triple glazing units have a 4/16/4/16/4 configuration as previously described.

More precisely, 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, a 95 nm thick antireflection layer of porous silica with a refractive index of 1.33 is additionally positioned on face 3 of the TGU. The stack (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 layers of porous silica with a refractive index of 1.33 are positioned on faces 2 and 3 of the TGU, respectively, with respective thicknesses of 332 nm and 99 nm.

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

The results are reported 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 You 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 You 0.2 0.4 0.2 Ag 11.7 14.1 15.3 ZnO 5.0 5.0 5.0 TiO ₂ 20.3 20.7 21.5

4*/16 /4

It is also observed that, for the same TL of 68.5%, the addition of the antireflection layer on face 3 and the adjustment of the antisolar stack results in a 5% decrease in the g factor (comparison of examples 2a and 2b). The gain can be even more significant (9.5% decrease in g) if two antireflection stacks, respectively on face 2 and 3, are combined with the antisolar stack 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 multiple glazing incorporating:

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

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. Multiple glazing according to claim 1, in which 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. Multiple glazing according to the preceding claim, in which said layer comprises porous silicon oxide, in particular nanoporous, mesoporous or macroporous. Multiple glazing according to 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 one of the preceding claims in which the thickness of said single layer present on face 2 is between 90 nm and 400 nm. Multiple glazing according to one of the preceding claims, in which the light transmission is between 45 and 85%, preferably between 60 and 80%. Multiple glazing according to one of the preceding claims, in which said second coating with anti-reflective properties is deposited on face 3 of the second substrate. Multiple glazing according to one of the preceding claims, in which said second coating with anti-reflective property 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 one of claims 1 to 8, in which a coating with anti-reflective properties is deposited on face 3 of the second substrate and a coating with anti-reflective properties is deposited on face 2 of the first substrate, between the glass surface and said first coating. Double glazing according to one of the preceding claims, obtained by the association of two glass substrates (10, 30) separated by a gas blade (15), 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. Double glazing according to the preceding claim, in which said first coating is present on face 2 of said first substrate (30), and in which 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 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 one of the preceding claims, in which 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, 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 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).